I l ips, Douglas R., comp. 

1987. Proceedings of the fourth biennial southern silvicultural rese 

rence; 1986 November 4-6; Atlanta, GA: Gene Tech. Rep. SE-42. Ashe 

* U.S. Department of Agriculture, Forest Service, Southeastern Fore 

riment Station. 598 pp. 

racts and 93 papers are presented in 13 categories: Pine Reg 

Fi re, Hardwood Regeneration, Pi ne-Hardwood Regeneration, Se 

presentations are summarized, and five papers from the general se 

Id Forestry Trends Affecting Southern Si lvicul ture are included. 

The use of trade or company names of products or services 

in the proceedings is for the benefit of the reader. Such 

use does not constitute an endorsement or approval of any 

service or product by the conference sponsors to the exclusion of others that may be suitable. 

Remarks about pesticides appear in some technical papers 

contained in these proceedings. Publication of these statements does not constitute endorsement or recommendation of 

them by the conference sponsors, nor does it imply that uses 

discussed have been registered. Use of most pesticides is 

regulated by State or Federal law. Appl icable regulations 

must be obtained from appropriate regul atory agencies. 

CAUTION: Pesticides can be injurious to humans, domestic 

animals, desirable plants, and fish or other wild1 ife--if 

they are not handled or applied properly. Use all pesticides 

selectively and carefully. Follow recommended practices 

given on the label for use and disposal of pesticides and 

pesticide containers, 
Proceedings of the 

Fourth Biennia Southern 

Silvicultural Research Conference 

Compiled by 

Douglas R. Phillips 

Atlanta, Georgia 

November 4-6, 1986 

Sponsored by 

Southern Forest Experiment Station 

Southeastern Forest Experiment Station 

Southern Region of the 

National Association of Professional 

Forestry Schools and Colleges 

Southern Industrial Forestry 

Research Council 

Silvicultural Working GroupSociety of American Foresters 

Published by 

Southeastern Forest Experiment Station 

Asheville, North Carolina 

1987 
PREFACE 

The Fourth Biennial Southern Silvicultural Research Conference was held in At1 anta, Georgia, on 

November 4-6, 1986, This vol ume contains 104 presentations from the 21/2-day conference, The weti ng 

opened with a general session on World Forestry Trends, followed by four concurrent sess'ions covering 23 

areas of research and a poster session. The general session was conducted for only the second time, and 

the pdster session was presented for the first time; both were well received, In addition, a new session 

on pine-hardwood mixtures was added to the agenda, Also for the first time, abstracts of the papers were 

printed and distributed at the meting, At this fourth conference, the Society of herican Foresters was 

added as a new sponsor. 

Initiated in 1980 and held in November on succeeding even-numbered years, the Southern Silviculturat 

Research Conference provides a forum for scientists actively engaged in silvicultural research do report 

study results, to present new concepts and techniques, to discuss topics of mutual interest, to coordinate 

cooperative efforts, and to remain current on developments in the field, Nonresearchers find the canferences and the proceedings to be valuable sources of information on current and developing trends in 

southern silviculture, 

The Fourth Biennial Conference was sponsored by the Southeastern and Southern Forest Experiment 

Stations of the USDA Forest Service, the Southern Region of the National Association of Professional 

Forestry Schools and Colleges, the Southern Industrial Forestry Research Council, and the Silvicultural 

Working Group sf the Society of American Foresters. 

The Steering Committee, made up of individuals from universities, industry, and the Forest Service, 

are gratefully acknowledged for the time and effort they gave to assure the success of the meeting, 

Following are the members of the 1986 committee: 

Jim Be1 1 and John W. Henley, Conference Co-chai rpersons, Southern Forest Experiment Station, 

New Orleans, LA 

Gordon D. Lewis , Conference Co-chai rperson, Southeastern Forest Experiment Stat ion, 

Asheville, NC 

Doug1 as R. Phi 11 ips , Program Chai rperson, Southeastern Forest Experiment Station, 

Clemson, SC 

M, Boyd Edwards, Southeastern Forest Experiment Station, 

Dry Branch, GA 

Constance A, Harri ngton, Southern Forest Experiment Stat ion, 

Monticello, AR 

David L. Graney and Edwin R. Lawson, Southern Forest Experiment Station, 

Fayetteville, AR 

David H, Van Lear, Clemson University, 

Clemson, SC 

Eric Jokela, University of Florida, 

Gai nesvi 11 e, FL 

D. M. Crutchf ield, Westvaco Corporation, 

Summervif le, SC 

Howard Hanna and Tim McIlwain, Container Corporation of America, 

Fernandina Beach, FL 

Special thanks are extended to the contributors who prepared and presented research papers and to 

the 16 moderators who presided over topic sessions and maintained a very strict time schedule, Thanks 

also to others who submitted abstracts for consideration by the Program Committee and to those who 

attended the conference and participated in the discussions, 

Papers published in this proceedings are as they were submitted by the authors--in camera-ready 

form, Authors are responsible for the content and accuracy of their papers, Printing and production were 

supervised by the editorial staff of the Southeastern Forest Experiment Station, USDA Forest Service, 

Asheville, North Carolina. 

DOUGLAS I?, PHILLIPS 

Program Cha i rman 
MllRtD FORESTRY TRENDS AFFECTSVG S;SIJTi-rERY S%LVIICij"LT~JQE 

Techno1 ogy Devel oprnent for Increased Use of Hardwoods ................. 3 

Peter J. ince 

International Trade and Ssuthern Forests ........................ 8 

dames E, Granskoy 

The Latin herican Forestry Experience ......................... 13 

J, Zweede 

Current and Future Wood Supply Trends in Australia, New Zealand and Chile ....... 16 

W.R,Se Sutton 

The Pulp and Paper Industry in the Nordic Countries in an Era of Increasing 

International Competition ............................... 24 

~ari Pesonen 

PINE REGENERATION 

Slash Pine Plantation Spacing Study--Age 30 ...................... 45 

EarJe P, Jones, Js, 

Converting "The Barrens" From Low-Qua1 ity Hardwoods to High-Yieldi ng Lob1 01 1 y 

PinePlantations ................................... 50 

Edward Buckner, Richard Evans, John Mullins, and Eyvind 7220s 

Relationships Between Height Growth and Root System Orientation in Planted 

and Seeded Lob1 ol l y and Short l eaf Pines ........................ 53 

Constance A, Warrington, Gllian 6, Carlson, and John C, Brissette 

Nursery Cultural Practices, Seed1 ing Morphology, and Field Performance of 

Longleaf Pine. .................................... 61 

Glyndon E, Hatchell 

Effect of Time and Depth of Planting on Survival and Growth of Loblolly Pine 

(Pinus taeda L.) Seedlings in Texas .......................... 67 

M, Victor Bilan 

Annual and Geographic Variations in Cone Production by Longleaf Pine .......... 73 

William D, Boyer 

Eva1 uation of Seed Vigor in Longleaf, Shortleaf, Vi rginia, and Eastern 

White Pines ...................................... 77 

F . T. Bonner 

The Effect of Seed Treatment and Sawing &tRod on Germination of Ocala Sand Pine .... 81 

Kenneth W, Outcdlt 

A Comparison of Natural Regeneration Alternatives for a Loblofly Pine Forest in 

the Lower Piedmont sf Georgia ............................. 84 

M, Boyd Edwards 

PRESCRIBED FIRE 

Regeneration of Hardwood Coppice Fol lowing Clearcuttiny With and Mi thout 

Prescribed Fi re .................................... 89 

Me K. Augspurger, D, He Van Lear, S, K. Cox, and B, Re Phillips 

Prescribed Burning in btuse Pine-Hardwood Stands--Effects on Hardwoods and 

Small Mammals ..................................... 93 

De L. Sanders, D, W, Van Leas, and D, C, Guynn 

Prescribed Fire for Precommercial Thinning in a Four-Year-Old Lob101 ly Pine Stand ... 37 

~homas A, Waldrop and F, Thomas Woyd 
An Insight Into Thinning Young Slash Pine Stands With Fire ............... R. W, Johansen and D, D. Wade 

Relating Wildland Fire to Defoliation and Mortality in Pine .............. Dale D, Wade and R, W. Jahansen 

HARDWOOD REGENERATION 

Regeneration of Appalachian Upland Hardwood Stands Seven Years After Clearcutting ... Thomas E. Blount, James E. Cook, mvid Wm. Smith, and Terry L. Sharik 

Regrowth After Complete Harvest of a Young Bottomland Hardwood Stand .......... John K. Francis 

Regeneration of Bottomland Hardwood Sites by Pre-Harvest Planting ........... Je L. Chanbers, W. 6. Stuhlinger, and R.G.P. Clifton 

Cherrybark Oak Enrichment Plantings Appear Successful After Seven Years in 

South Carolina Bottomlands .............................. L. 6. Nix and S. K. Cox 

Studies on the Biology of Cherrybark Oak: Recommendations for Regeneration ...... John D. Xodges and Greg Janzen 

Sycamore Coppice Response to Harvest Season: 7-Year Trends .............. Kenneth R. Roeder 

Short-Rotation Seedl ing and Coppice Biomass Yields and Nutrient Content of Seven 

Tree Specjes in North Carolina ............................ S, J, Torreano and D. J. Frederick 

PINE-HARDWOOD REGENERATION 

Silvicultural Implications of Mixed Pine-Hardwood Stands in the Piedmont ........ Herbert A. Knight and Douglas R. Phillips 

Growth and Devel opment of Short 1 eaf Pi ne-Hardwood Mi xed Stands Four Years 

After Regeneration .................................. Douglas R. Phi2 lips and James A. Abercro;nbie, Jr. 

Coppice Regeneration in the Oak-Pine Type Relative to Initial Species Composition, 

Stand Structure, and Season of Fell ing ........................ James bd, McMinn 

Even-Aged Regeneration A1 ternatives for Low Qua1 i ty Mi xed Hardwood Forests in the 

Virginia Piedmont................................... 

Keith P. Newcomer, Shepard M. Zedaker, David Wm. Smith, and Richard E. Kreh 

Evaluation of Sampl ing Methods to Estimate the bevel of Competing Hardwood 

Vegetation in Young Lob101 ly Pine Plantations ..................... D* R, Weise and G, R. Glover 

Simulating the Effect of Hardwood Encroachment on Loblolly Pine Plantations ...... W, D. Smith and We L. Hafley 

SEEDLING PRODUCTION 

The Influence of Seedbed Density on Loblol ly and Slash Pine Seed1 ing Grade 

Distributions ...................................... James N, Boyer and David B. South 

Effects of Nursery Bed Density and Ferti 1 i zation on the Morphology, Nutrient Status, 

and Root Growth Potential of Shortleaf Pine Seedlings ................. John C. Brissette and William 6, Carlson 

Relationships of krphological Root and Shoot Characteristics to the Performance of 

Outplanted Bareroot and Containerized Seedlings of Loblolly Pine ........... Jean A. Wlilder-dyers and John R. Toliver 
Page 

SOIL 

Effection of Carbon Dioxide Enrichment on Growth and Field Survival of ContainerGrown Pinus taeda L, Seedlings ............................ 212 

WiJiia~ A, Retzlaff, Ansel E. Miller, and Joe E, Toler 

Containerized White Pine Seedling Development Five Years After Outplanting ....... 217 

R I L, Hay and J, C, Rennie 

Long1 eaf Pine Seedl i ng Storabi 1 i ty and Resistance to Brown-Spot Disease Improved 

by Adding Benomy1 to the Packing Medium ........................ 222 

James P, Barnett and Albert G. Kais 

Lateral Root Devel opment Nay Define Nursery Seedl i ng Qua1 i ty .............. 225 

P P, Kornanik and J. L, Ruehle 

A 15 Day Hydroposrjc System for Fktastsring Root Growth Potential : Measurement and 

Sample Size for bsblol ly Pine ............................. 230 

Robert C. Freyaan and Peter P, Feret 

Root Growth Potent i a7 and htpl anti ng Performance of Lob1 01 1 y Pine Seedl i ngs Rai sed 

at 2 Nurseries .................................... 237 

Char-Zes Je Barden, Peter P. Feret, and Richard E. Kreh 

Root Growth Potential as a Predictor of First year Field Performance for Non-Irrigated 

and Irrigated Eastern White Pine Seedlings ...................... 245 

K. H. Johnsen, P, P. Feret, and J. Re Seiler 

SITE-STAND RELATIONSHIPS 

Integrated Site Classi fieation in the Southern Appalachians: Geologic Variables 

Related to Yellow-Poplar P~~ductivity. ........................ 253 

66, Henry WNab 

bthods for Refining Growth-Si te Index and Envi romental Factors Relationships for 

Loblol ly Pine on Certain Soil Series of the Lower Coastal Plain [Abstract ] ...... 259 

ldaril yn A. Buford and William He WKee, Jr. 

Response of Cherrybark Oak Families to Different Soil-Site Conditions ......... 260 

Stephen Ge Dicke and John R. Toliver 

SILVICULTURE-ECONOMXC RELATIONSHIPS 

Production and Fi nanei al Csmpari sons of Uneven-Aged and Even-Aged Management of 

toblol ly Pine ..................................... 267 

James B, Baker 

Economic Assessment of Chemical Versus Mfichanical Site Preparation ........... 274 

Clifford A, Eickman, Walter C. Anderson, and Richard hi. Guldin 

Growth and Economic Gompari sons of Selected Natural ly and Arti f icial ly Regenerated 

Stands ........................................ 283 

Michael T, iYenyak, Dilvid H. Van Mar, Stephen K. Nodine, and David C. Guynn, Jr, 

Financial Analysis of Artificial Pine Regeneration and Natural Regeneration Using 

lmprovementCuts ................................... 290 

Stephen K. Nociine and Arthur T. Shearin 

Ten Years After Midrotation Ferti l ization in Slash Pine Plantations: When Does 

ItPay? ........................................ 294 

Duane R, Dippon and McrAamad Hassan 

Twenty-Year Slash Pine Spacing Study: What to Optimize? ................ 300 

Doug Bowling 

Federal Income Tax Treatment cP Silvicultural and Related Costs Associated With 

Intermediate Stand bnagement ............................. 305 

William C, Slegel 

Compaction Alters Soi 1 Physical Properties and Root Growth of Inoculated and 

Noninocul ated Ye1 low-Pop1 ar and Sweetgum Seed1 ings .................. 6. L. Simons and P. E, Pope 

Pine Growth Improvement on Logging Sites With Site Preparation and Fertilization .... W. H, McKee and G. E. Hatchell 

MANAGEMENT OF ESTABLISHED STANDS 

Precommercial Thinning of Pine Regeneration in Uneven-Aged Stands ........... Michael D. Cain, James B. Baker, and Paul A. Murphy 

Slash Pine Shows Mixed Response to Potassium Fertilizer ................ Eugene Shoulders and Allan E. Tiarks 

Effect of Legumes on Pine Growth in Thinned Loblolly Pine Plantations ......... Terry R. Clason 

Early Results of Silvicul tural and Ecological Impacts of Harvesting Systems in Thinning 

Loblolly Pine Plantations ............................... Timothy R. Bottenfield, Michael S. Golden, Ralph S. Meldahl , Jon P. Caulf ield, 

Bobby L. Lanford, and Donna N. Terry 

Development of Intermediate and Suppressed Loblol ly Pines Following Release ...... B . F. McLemore 

Ten-Year Growth of Red and White Oak Crop Trees Following Thinning and Fertilization 

in the Boston Mountains of Arkansas .......................... D. L. Graney 

Management Options for Southern Appalachian Hardwoods: The Two-Aged Stand ....... Donald E. Beck 

Development of Advanced Oak Regeneration as Influenced by Removal of Midstory and 

Understory Vegetation ................................. G. C. Janzen and J. D. Wodges 

Response of a Second-Growth Natural Stand of Baldcypress to Various Intensities 

of Thinning ...................................... J. R. Toliver, S. G. Dicke, and R. S. Prenger 

A Comparison of Biomass and Nutrient Content in Piedmont and Coastal Plain Bottomland 

Hardwood Stands .................................... M. A. Megalos, D. J. Frederick, A. Clark 111, and D. R. Phillips 

Swamp White Oak Response to Various Levels of Nitrogen and Phosphorus--Surface 

Appl ied [Abstract ] ....................... .. ......... John R. Seif ert and Phil E . Pope 

The Effect of Thinning and Pruning on the Growth of Planted Loblolly Pine Stands .... Daniel J. Leduc and Boris Zeide 

GROWTH AND YIELD 

Estimating the Amount of Wood Per Acre in Loblolly and Slash Pine Plantations in 

East Texas ...................................... J. David Lenhart 

Update of Long Term Loblolly Pine Plantation Growth and Yield Study on the Clemson 

Experimental Forest.................................. 

L. E. Nix, A. T. Shearin, and S. K. Cox 

An Ecological Derivation of Stand Structure in Balanced Uneven-Aged Lob1 01 fy-Short1 eaf 

Pine Stands of the West Gulf Region .......................... James M. Gul din 
Page 

Growth and Yield of Sweetgum-Cherrybark Oak Mixtures LAbstract ] ............ Thomas G. Matney, Joi?.n I). Hodges, and Alfred D. Sullivan 

A Mew and Simple Method for Modeling Stand and Stock Tables .............. Bruce E. Borders and Ray A. Souter 

In Search of an Improved Sawtimber Stand Volume Function ................ Robert M. Farrar, Jr., and Paul A. Murphy 

Recovering Diameter Distributions From Schumacher and Coi 1 e's Model for Natural 

Even-Aged Lobl 01 ly Pine Stands ............................. Quang V. Cao 

The Prediction of Data Into Multiple Categories Using a Form of Logistic Regression . . R. K. Bolton, R. S. Meldahl, and M. Eriksson 

Preserving and Maintaining Permanent Growth & Yield Research Plots ........... J. David Lenhart 

Incorporating Precipitation Into a Basal Area Growth Model ............... Paul A. Murphy and Robert M. Farrar, Jr. 

PEST MANAGEMENT 

Impact of Pine Tip Moth Attack on Loblol ly Pine Seed1 ings ............... Roy L. Hedden and D. A. Haugen 

A Crown Rating Method for Assessing Tree Vigor of Loblolly and Shortleaf Pines ..... R. L. dnderson and R. P. Belanger 

Selection of Southern Pine Beetle Hazard Rating Systems for Mississippi ........ C. R. Honea, T. E. Nebeker, and J. D. DeAngelis 

Effect of Fusiform Rust on Survival of Loblolly Pine in Unthinned Plantations ..... Warren L. Nance and Eugene Shoulders 

Quantifying the Effects of Fusiform Rust on Tree Basal Area Growth in Slash Pine 

Plantations ...................................... W. Michael Harrison and L. V. Pienaar 

Management and Pest Management Considerations on Droughty Soils: Four Year Results . . David L. Kulhavy, Kenneth G. Watterston, James C. Kroll, and James R. Meeker 

VEGETATIVE MANAGEMENT 

Re1 ationships Among Fi rst-Year Lobl 01 ly Pine Seed1 ing Performance, Vegetation Regrowth, 

Environmental Conditions and Plantation Management Practices .............. Sarah M. Nusser and Thomas R. Wentworth 

Impact of Intensive Competition Management on Dominant Stand Height .......... G. Lbniel Ayers, Terry R. Clason, and William D. Smith 

A Region-Wide Study of Loblolly Pine Seedling Growth Relative to Four Competition 

Levels After Two Growing Seasons ........................... James H. Miller, Bruce Zrrtter, Shepard M. Zedaker, Michael Cain, M. Boyd Edwards, 

G. Kenneth Xydias, A. R. Applegate, R. Lee Atkins, Sam Campbell, Edward Daly, 

Charles Hollis, Steven A. Knowe, and Jeff Paschke 

Piedmont Bottomland Hardwood Regeneration Responds to Preharvest Japanese Honeysuckle 

Control........................................ 

E. J. Schmeckpeper, R. Lea, D. Phillips, and L. Jervis 

viii 
World Forestry Trends Affecting Southern Silviculture 

Moderator: 

Robert C. Kellison 

North Carolina State University 

Technology Development for Increased Use of ~ardwoods' 

Peter J. 1nce2 

Abstract.--New developments in technology are altering the historical 

dominance of softwood over hardwood as a preferred raw material for many 

kinds of products. Developments span the whole range of forest products, 

from traditional products such as lumber, wood panels, and paper, to 

energy uses and biotechnology. In the lumber-area, new drying technology 

overcomes the problem of excessive warp in low density hardwoods and 

permits their use for framing lurnber, In addition, new technologies are 

being developed to make lumber substitutes from wood strands or wafers, 

that enable use of higher density hardwoods in applications where softwood lumber is used exclusively today. In the structural panel area, 

waferboard and oriented strandboard panels are replacing conventional 

softwood plywood in a substantial share of the market. These new panel 

products can be made entirely from hardwoods. In pulp and paper, 

a general trend toward greater use of hardwood fiber is evident as the 

proportion of industry capacity dedicated to production of printing and 

writing grades increases. Also, improvements in pressing, drying, and 

refining technologies are allowing high quality linerboard to be made 

with much higher proportions of hardwood. A growing use of wood for 

energy, in residential heating and industrial uses, favors hardwoods 

because of their higher density. Finally, through biotechnology, hardwoods will probably play a more significant role than softwoods. 

Consequently, silvicultural knowledge about lower valued timber species, 

such as hardwoods, needs to bt3, developed for the future, 

Keywords: Technology, hardwoods, silviculture. 

INTRODUCTION OBBCTIVES OF SILVICULTUaAL RESEARCH? 

This paper addresses ongoing technology 

developments for increased use of hardwoods. 

A wide range of technological and economic 

developments are described that are reducing the 

advantage of softwood over hardwood as a preferred wood raw material, 

These developments reflect a principle of 

human behavior which I call the "leveling 

principle." The principle says that when less 

expensive resources are available, people develop 

new technologies to use less expensive resources. 

Thus, people seek to level the advantages of 

more expensive resources in order to improve 

economic efficiency. This kind of very rational 

human behavior presents complexity for silvicultural researchers, because it means that as 

you focus your objectives on timber species that 

you think will have the highest value in the 

future, others will be trying consciously and 

vigorously to develop new technologies to utilize 

the less expensive timber species. 

lThis paper was presented in the General 

Session of the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, GA, 

Nov. 4-6, 1986. 

2Ret;earch Forester, Forest Products 

Laboratory, U.S. Department of Agriculture, 

Forest Service, Madison, WI 53705-2398. 

Let me begin by asking a very general question: 

What are the objectives of silvicultural research 

in the South? No doubt you've wrestled with this 

question before. If we had time to ask everyone 

about silvicubtural research objectives, we would 

probably find a variety of ideas. However, among 

the most practical objectives we would find a 

common goal something like the following: to 

expand knowledge needed to improve abundance and 

quality of timber resources which society will 

demand in the future. 

The problem is that we can't say for certain 

what kind of timber resources society will demand 

30 or 40 years from now, so it's difficult to 

say what kind of silviculturah knowledge needs 

to be developed. It would be easy to set silvicultural research objectives if we could believe, 

for exaqle, that growth in the southern pine 

plpood industry, observed in the past 20 years, 

will coatiaue into the next century, But, 

believe Be, that would ignore some important 

developments taking place in structural panel 

technology. 

Evidence suggests that future forest product 

technology is not necessarily going to be anything like the past. Industry is developing 

technologies to level the advantages of higher 

value timber resources and to enable the use of 

lower value timber resources, For example, 

technology is being applied that allows the use 
of low density hardwoods or softwood pulpwood 

in place of softwood veneer logs in manufacturing 

structural panels. Developments are occurring 

also in lmber, structural panels, pulp and 

paper, energy, and biotechology. We will look 

at specific examples in each of these areas. I 

hope that as f discuss these examples, you will 

recognize their significance in terms of silvicultural research objectives in the South. Let's 

look first at the framing lumber area. 

roduce Hardwood 

Softwood dominates the market for framing 

lwber in the United States. Last year, we 

conswed nine times as much softwood lumber as 

hardwood, and in structural framing we depend 

entirely on softwood. 

Historically, industry has avoided the use of 

low density hardwoods for framing lumber largely 

because of the problem of excessive warp, Years 

ago, grading rules were established which limited 

allowable warp to small fractions of an inch in 

all but the lowest grade of framing lumber. 

Because of the way that framing lumber is used 

in modern construction, each piece needs to be 

dimensionally precise and stable. Unfortunately, 

hardwood lumber would typically come out of a 

conventional sawmill and drying process with 

excessive warp. Because of this dimensional 

stability problem, production of hardwood framing 

lmber was not economical. 

However, in our Eastern forests, net growth 

and volunne of hardwood exceed that of softwood. 

Forests in the South contain increasingly 

abundant quantities of inexpensive low density 

hardwoods such as yellow-poplar, sweetgum, 

blackgm, and soft maple. These hardwood species 

have strength values between southern pines and 

spruce-pine-fir, and can be nailed easily or 

joined with truss plates. 

Researchers have now developed a sawmilling 

innovation that eliminates the problem of excessive warp in hardwood framing lumber. The innovation is called Saw-Dry-Rip, or SDR. With SDR 

technology, the mill saws a log into full width 

flitches. The flitches are dried, and then sawn 

(or 'kQpedfi) into warp free framing lumber. 

The key innovation is that framing lumber is cut 

from the wood after drying, instead of before, 

as in conventional sawmilling. This simple 

innovation eliminates the problem of warp 

(Maeglin and Boone 1383). 

Recently, a recornended grading stamp was 

developed For yellow-poplar framing lwnber, and 

building codes will now accept yellow-poplar 

lrannber (Allison and Deal 1983). The new hardwood 

lunaber is less splintery than softwood, is 

lighter and easier to handle than southern pine, 

and tests show that yellow-poplar lumber bas 

bigher truss plate holding capacity than southern 

pine, la demonstration projects, the hardwood 

lwnber appears to be a very attractive structural 

material. 

With SDR technology, you can envision a sawill 

able to use either low density hardwoods or 

softwoods. In the future, there will be less 

differentiation between softwoods and Isw density 

hardwoods for framing lumber. 

The point T am making is not a forecast but 

simply a recognition cf present capability. The 

technology is now available which levels the 

advantage of softwoods over low density hardwoods 

in framing Lwber, So long as softwoods remain 

economical and abundant, as they are now, you can 

expect that softwoods will continue to dominate 

the framing luntber market. But, if softwood 

becomes too expensive relative to low density 

hardwoods, you can expect to see a switch to 

hardwoods. If you are a silvicultural researcher 

developing knowledge based on an assuption that 

softwood sawtimber will have a tremendous market 

advantage over hardwood in the decades ahead, I 

would suggest that you might go back over your 

assumptions. You might also consider silvicultural research objeceives that will foster 

improved management of the low density hardwood 

resource in the South. 

Structural Panels 

The structural panel market is also an area in 

which softwood traditionally dominated, but where 

things are now changing. 

Until recently, softwood plpood thoroughly 

dominated the structural panel market.. Softwood 

plywood itself was a major technological developmeat of the early part of this century, and the 

softwood pl-wood industry grew tremendously in 

the South in the 1960's and 1970%. Today, more 

than half of U.S. softwood plywood is produced 

in the South. There is no doubt that the 

tremendous growth of the southern pine plywood 

industry contributed enormously to an enthusiasm 

for pine silviculture in the South. 

However, if you look closely at construction 

sites around the country these days, you will 

see that a growing share of the structura1,panels 

are a new class of products, known in the market 

as waferboard and OSB (oriented strandboard). 

In the 1970's at the Forest Products Laboratory 

we developed computer models of manufacturing 

processes for these kinds of products. We were 

quite enthusiastic about how economical the 

process was relative to conventional plwood 

technology. Part sf the reason for our enthusiasm was the fact that waferboard and OSB technology offered the ability to use lower quality 

timber, such as pulpwood instead of veneer logs, 

and hardwood instead of softwood. As many of 

you know, this kind af technology exists now, 

not just in the form of a computer model, but in 

the form of a growing and rapidly expanding 

iadust ry . 

The new waferboard and OSB structural panel 

products provide excellent structural performance 

and are accepted by building codes as a subslitute for softwood pipood in most types of construction. Although performance is cowarable 
to softwood plpood, the new waferboard and OSB 

products are cheaper to produce. As a result, 

we have seen the industry installing new waferboard and OSB mills in significant nwnbers in 

recent years, while we see almost no capacity 

expansion in softwood plpood, 

Growth of the U.S. waferboard and OSB industry 

has been exponential. From only one plant with 

a capacity of 100 million square feet as late as 

1979, the industry has grown to a capacity of 

nearly 4 billion square feet, by late 1986, and 

the growth is continuing (Anderson and Hutton 

1986). Today, waferboard and OSB capacity equals 

nearly 20 percent of U.S, softwood plywood production, and 12 percent of total structural panel 

capacity. Industry is locating many of its new 

waferboard and OSB mills throughout the South. 

Many new waferboard and OSB mills in the South 

will be using southern pine pulpwood because of 

the economic abundance of the resource and good 

board quality that is obtained with southern 

pine. Bowever, there is a demonstrated ability 

to use many species of hardwoods in the waferboard and OSB products. Host mills in the North 

use hardwood species exclusively, and some mills 

in the South are using hardwood species as well. 

Besides being economical to produce, waferboard 

and OSB products offer much more latitude for 

product innovation. Structural comonents can 

be made in an infinite variery sf molded forms 

and shapes which are not attainable with conventional lumber or plywood technology. Most significantly, unlike structural wood products of 

the past that were made entirely out of softwoods, the structural products of the future can 

be made out of small diameter hardwoods, using 

techohogy similar to waferboard and OSB technology. Even the hardwoods such as oak may be 

useful, as in thick roof decking samples that 

have been made in the laboratory from southern 

red oak. Simple innovations, such as using 

longer strands or detaining better strand alignment, will also enable the industry to take full 

advantage of the inherent strength in dense 

hardwood species. The market is already seeing 

the introduction of high strength parallel strand 

lumber, made by gluing together long strands of 

wood. In the future, lumber substitutes and 

complete structural components may be made from 

hardwood wafers and strands, using technplogy 

similar to waferboard and OSB. 

Once again, I am not really making a forecast, 

but simply pointing out the current status of 

technological development. If your silvicultural 

research objectives are based on an asswtion 

that there will be growing demands for softwood 

veneer logs, I would suggest that you go back 

over your assumptions. Structural panel products 

can be made economically from small diameter, low 

quality, hardwood species, as well as from small 

diameter softwoods. 

Technology to Utilize Hardwood 

The U-S. pulp and paper industry is another 

important market area where softwoods have 

dominated, but where new technology is leveling 

advantages of softwoods over hardwoods. Pulpwood consumption increased over the last 28 years 

by about 75 percent, to a present level of 

90 million cords per year. Over 65 percent of 

that pulpwood comes from Soutbern forests, As 

most of you know, the largest share of that 

pulpwood is southern pine, and pine pulpwood 

generally has a higher value than hardwood 

pulpwood, 

The technical advantages of pine versus bardwood can be explained in terms of morphoiogical 

differences between softwood and hardwood fibrous 

material. Softwood fibers are comparatively long 

and flexible. Softwood fibers naturally provide 

good strength characteristics in products like 

kraft linerboard. By coqarison, hardwood 

fibers are generally smaller, shorter, and less 

flexible, Consequently, hardwood does not provide good strength perfomance with conventional 

technology, although hardwood can provide 

a smoother sheet with better opacity, which is 

useful in printing and writing grades (bidon 

1981>. 

One major technological trend is toward 

increased production of those grades sf pulp and 

paper products which utilize more hardwood fiber. 

Production of hardwood-based pulps, which include 

bleached and semibleached hardwood kraft and 

semichemical pulps, has increased more rapidly 

than production of all other grades of pulp* 

Consequently, in the South, we have seen hardwood 

pulpwood go from around 15 percent to nearly 

30 percent of pulpwood consumption in the past 

30 years (Ince 1986). This trend is continuing, 

particularly with recent conversions of a amber 

of mills from packaging grades to printing and 

writing grades. Even in packaging grades, %he 

need for good surface printability has led a 

number of mills to increase their demand for 

hardwood furnish. These gradual changes, 

favoring increased use of hardwood pulpwood, are 

expected to continue in the future. However, a 

much more dramatic kind of technological development is uademay, and that involves development 

of new technology that will produce high strength 

paper and paperboard products from hardwood 

fiber, 

Nanufacturing pulp and paper involves a series 

of process steps. Wood chips are converted into 

pulp in digesters and refiners. The gulp goes 

in a slurry to the paper machine, where pulp is 

formed into a fibrous mat, pressed, and subsequently dried. Conventional gapemaking is 

largely a felting process, in which sheet 

strength depends on random interlocking and conformability of fibers. Therefore, long flexible 

softwood fibers have always provided better 

strength than short stiff hardwood fibers. 

However, in recent years, new pressing equipment, including high pressure and wide nip 
presses, have been installed in many linerboard 

mills. With the new equipment, much better 

quality is obtained with higher proportions of 

hardwood and recycled fiber (Wicks 1953). 

Furthemore, researchers have developed an even 

more actb-anced technology, known as press drying, 

Unlike conventional papermaking, press drying 

involves simultaneous application of heat and 

pressure in the press section of the paper 

machine, resulting in good conformability and 

bonding among hardwood fibers. With press 

drying, a very good kraft linerboard can be made 

from 100 percent hardwood, such as southern red 

oak (Horn and Setterholm 1983). The press drying 

technology is not yet available comercially, 

but it appears economical, and it illustrates 

a potential technological capability to utilize 

much higher proportions of hardwood fiber in 

pulp and paper products. In addition to improved 

pressing technology, improvements are being made 

in techn~logy for refining pulp fibers, for 

putting strength enhancing chemical additives in 

paper and paperboard, and for producing higher 

quality hardwood pulp with mechanical pulping 

processes. 

As a result of these technological developments, there has been a significant leveling of 

the former advantage of softwood fiber in pulp 

and paper technology. The industry has only 

begun to adopt these tecknological improvements, 

and change will be gradual, but we can no longer 

point to a future in which softwood fiber will 

absolutely dominate because of its fiber characteristics. In fact, it is possible to conceive 

of a future in which hardwood fibers may be 

preferred over softwood fibers in pulp and paper 

technology. 

The Increasing Importance 

of Wood for Energy 

Another development favoring the future use of 

hardwood is the increased importance of wood for 

energy in our economy. As a result of energy 

price shocks in the 1970's, we have seen a substantial shift toward increased use of wood for 

residential heating, particularly in rural 

America. Even though the South has a warmer 

climate than northern regions, fuelwood use is 

significant because of a large rural population. 

Across the United States, we are consuming about 

49 million cords of fuelwood for residential 

heating per year (Energy Information 

Administration 1984). Of the 49 million cord 

total, about 16 million cords are conswed in 

the South, In addition, several million cords 

of fuelwood are being used directly for industrial energy. Provided that petrole- and gas 

prices stabilize in the years ahead, 1 expect to 

see a leveling off of the increase in fuelwood 

demand. Still, I would expect that fuelwood 

will continue to be an important use for wood in 

the future. 

The important thing about the increased use of 

wood for energy is that hardwood species are 

preferred by households, the major roundwood 

users. A nice seasoned piece of red oak burns 

better and longer than softwood in fireplaces 

and waodstcves. In all regions of the country, 

fuelwood producers have appeared. These commercial operations derive their income in the 

fuelwood market, Other woad product companies 

that have traditionally deraved income in different markets have also branched out into the 

fuebwood market. They advertise and sell their 

fuelwood in both rural and urban areas, amd are 

utilizing primarily hardwood, 

I'm net suggesting that silvicultural 

researchers should give total attention to the 

growth of hardwoods for fuelwood. There is 

certainly a tremendous abundance of low quality 

hardwoods in the South that will adequately 

serve needs for fuelwood in the future. However, 

in your process of establishing silvicultural 

,research objectives, you should consider not 

only such things as precomercial thinnings and 

pulpwood harvests in softwood stands, but also 

such things as fuelwood thinnings or fuelwood 

harvests in hardwood stands. Perhaps if fuelwood 

demand is put into the equation, you will find 

that hardwood silviculture Looks a little more 

attractive. 

Hardwood Use Associated 

A final area of technological development that 

I'd like to talk about is biotechnology. Most 

of you are aware of the importance that biotechnolegy has assunned In many areas of research. 

Biotechnobogy is no less important in the area 

of wood util.izaliox research. At the Forest 

Products Laboratory, we recently organized 

biotecbnology research into an institute, which 

we call the Institute for Microbial and Biochemical Technology. The scope of research in 

this area is expanding. The focus continues to 

be on basic research, with possible applications 

in biopulping, and promising applications in 

bleaching, modifying pulp properties, removing 

chemicals, and treating effluent (Kirk et. al. 

1983). 

Most of the wood biotecbnology research is 

directed at utilization of the abundant and 

inexpensive hardwood resource. For one thing, 

the molecular structure of hardwood and softwood 

fignias are different. Hardwood lignin is'more 

readily and rapidly biodegraded than softwood 

lignin, Another reason why biotechnology is 

focusing on hardwoods is a matter of economics. 

Hardwoods are relatively cheap and abundant, 

whereas softwoods are already in high demand. 

In addition, hardwood biotechnalogy is receiving 

greater attention because the chemistry of hardwoods is approximately the same as that of agricultural crop residues, which are also receiving 

much research at"cntion. Xylans, from which 

xylose sugar is derived, are abundant in hardwood hemicellulose and agricultural residues, 

but not in softwoods. Utilization of glucose 

sugars from ordinary ceflulose is already 

feasible, but utilization of xylose is one aim of 

current research. 

It is hard to say where this research will lead 

30 or 40 years from now, but it is apparent that 

the biotechaology of the future may just as 
likely utilize hardwoods as softwoods. In fact, 

due to differences in lignin chemistry and comparative economics, bio-utilization of hardwoods 

may be mcrc sear at hand than bio-utilization of 

softwoods* 

Change in techaology is a gradual process, so 

we wan" see a wholesale switch to hardwoods from 

softwoods overnight, or even in a matter of 5 or 

10 years. Change in forest management techniques 

is also a slow process, Wowever, to be effective 

in the future, changes in the philosophy of 

silvicultural research should be made today. 

Technological change is relentless and it can 

have profound inrpasts on resource utilization. 

Look at how iqrsvemeets in basic energy technology over the past 15 years have drawtically 

altered the world market for oil. There used to 

be an oil shortage, now there's an oil glut. Of 

course the leveling principle in human behavior 

is limi~ed by Laws sf thermodynamics and laws of 

nature. But, when we look at the forests of the 

Eastern United States, when we look at the differences between hardwoods and softwoods, and 

when we look at current human endeavors aimed at 

reducing the advantage of expensive softwoods 

over cheap and abundant hardwoods, we do see that 

this leveling principle is at work. In summary, 

there is a message here for silvicultural 

researchers: We should be critical of time-worn 

guidelines regarding such things as optimal 

species, stand conversion, site preparation, and 

other factors related to species distribution. 

When we do research that enables foresters of 

the future to grow timber resources that we think 

will have the highest value 30 or 40 years from 

now, others in society will be attempting consciously and vigorously to change technology in 

order to utilize other lower valued timber 

species, If we find that our research, particularly our basic research, is focusing narrowly 

an only a few species that are currently in high 

demand, we should consider how we can expand our 

research to focus on other species as well. It 

may be feasible for example to inexpensively 

replicate our exgeriments across a wider array 

of species, so that we develop more silvicultural 

knowledge about species that may be in greater 

demand in the future, We should recognize that, 

where feasible, silvicultural knowledge about 

lower valued timber species, such as hardwoods, 

needs to be developed for the future. 

Allison, Robert C.; Deal, Earl L. Yellow-poplar 

framing Imber. Morth Carolina Agricultural 

Extension Semite, Report AG-325. 

Raleigh, Morth Carolina; 1983. 6 p. 

Anderson, Robert G.; Hutton, Jay J. Regional 

production and distribution patterns of the 

structural panel industry, American Plywood 

Association. Report E41. Tacoma, Washington; 

1986. 31 p. 

Energy Information Abinistration. Residential 

energy conswption survey: Housing 

characteristics. Report DOEfEIA-0314(84). 

U.S. Department of Energy, Washington DC; 

1986- 238 p. 

Norn, Richard A.; Setterholm, Vance. Continuous 

on-line press drying of high-yield oak fiber 

for linerboard, Tappi Journal 66(6): 59-62; 

1983. 

Ince, Peter J. Changing technology will increase 

southern hardwood use in future. Pulp and Paper 

60(2): 59-63; 1986. 

Kirk, T. Kent; Jeffries, Tom W.; Leatham, Gary E. 

Biotechnology: applications and implications 

for the pulp and paper industry. Tappi Journal 

66(5): 45-51; 1983. 

Maeglin, Robert R.; Boone, R. Sidney. 

Manufacture of yellow-poplar studs using the 

saw-dry-rip (SDR) concept. Forest Products 

Journal 33(3): 10-18; 1983. 

Wicks, Laurie. Continued development and 

experience with the extended nip press. Tappi 

Journal 66(4): 61-64; 1983. 

bidon, Thomas E, Effect of the wood properties 

of hardwoods on kraft pager properties. Tappi 

Journal 64(3): 123-126; 1981. 
I/ INmRNATIONU TRADE ANI) SOUTBEm POBEST* 

2f James E. Granskoe 

Abstract.--The value of southern 

wood exports has dropped by more than a 

third since 1980, after rising sharply 

during the 1970's. Major factors in the 

recent decline were a worldwide recession 

and a strong U.S. dollar, which made 

southern wood products more expensive 

overseas. However, trends for individual 

products have varied; exports of softwood 

plywood and hardwood lumber have grown 

while other product shipments have fallen. 

Currently, a weakening U.S. dollar appears 

to be turning the overall trend for southern wood exports upward again. 

International trade is becoming increasingly 

important to our nation's economy. In 1985, 

imports and exports accounted for 21 percent of our country's gross national product--almost 

double the percentage from 20 years earlier. Perhaps more enlightening is that 70 percent of all 

products manufactured in this country now face 

international competition, In other words, mar- kets for most U.S. products no longer are determined solely by domestic forces. 

Timber markets also have been vulnerable to foreign influences. A strong rise in the value of 

the U.S. dollar in the first half of the 1980's-- 

which made U.S. products more expensive and foreign goods cheaper--has increased the flow of 

forest products from abroad, Domestic markets 

for lumber, pulp, and paper products have been 

impacted by rising imports of softwood lumber 

from Canada, and new inflows of eucalyptus pulp 

from Brazil and coated paper from Scandinavia. 

While recent events have focused attention on 

the import side of international trade, there has 

been nonetheless a growing interest in exporting 

forest products as well. This interest has been 

stimulated by a combination of factors, including: 

- unstable domestic markets for wood products over the past decade, 

- expanding foreign competition in certain product lines, 

- forecasts of slow growth in domestic wood 

markets and faster growth overseas, and 

- a national concern over a widening trade 

deficit and the need to increase the sale of 

products abroad. 

Lipaper presented at the Fourth Biennial Southern Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

-1'~rinci~al Economist, Southern Pores t Experiment Station, USDA Forest Service, New Orleans, LA 

70113. 

As a result, potential markets overseas are being 

viewed as a vital ingredient for future growth. 

To support the growing interest in exporting 

forest products, the Southern Forest Experiment 

Station has been conducting research aimed toward 

investigating the potential for southern wood 

products in overseas markets. In this paper, 

recent trends for the principal wood products 

exported from the South are examined, and the outlook for southern wood products in foreign markets 

is discussed. 

Although exports represent only a small fraction 

of total production for most southern forest products, they are important from a value standpoint. 

For the most part, export demand for wood products 

is for high-quality material. Exports can enhance 

timber values, thereby encouraging more complete 

utilization while providing incentives for more intensive silvicultural practices. 

SOUTHERN WOOD EXPORTS 

Southern exports of wood products have been 

declining since 1980, following a dramatic rise 

during the 1970's (table 1). The total value of 

southern exports rose from near the $50 million 

level in the early 1970's to almost $500 million 

in 1980, but it has dropped by more than a third 

since then. 

Several factors have influenced this rise and 

fall, but currency fluctuations have been a key 

item. The strong upturn during the 1970's was 

stimulated by a weakening U.S. dollar. In effect, 

prices for southern wood products--in terms of 

foreign currencies--were reduced. Other contributing factors to the upturn were: a rising 

demand overseas, other global sources becoming 

constrained by resource depletion or government 

restriction, and a growing recognition among 

domestic producers of the importance of diversifying markets. Trial shipments of wood chips to 

Scandinavia, in particular, seemed to trigger a 

greater awareness of the market potential abroad. 
Since 1980, hoever, changing economic and monetary conditions have turned the direction for 

southern mod exports domward. First, a worldwide economaic slowdown lowered total degtand. Then 

the continuing rise in the value of the dollar 

through early 1985 made southern mod products sore expensive and less competitive in foreign 

markets. But a rerent weakening of the U.S. dollar since Nsrch 1985 has stopped the decline and 

appears to be turning the trend upward again. 

Table 1.-Value of southern wood exports by product group. 

Product 1970 1975 1980 1985 

Million S 

Roundwood 15.3 26.9 93.4 52.2 

Lumber 26.6 37.0 206.0 160.0 

Panels 3.3 18.2 59.6 61.6 

Other 13.1 16.4 140.0 52 . 1 

Total 58 . 3 98.5 499.0 325.9 

EUROPE-EEC 

OTHER [3 

SO. FIRER1 

QFKICR 

EUROPE-OTHER 

Figure 1.--Export markets for southern wood 

produc ts . 

Products 

Trends since 1980 for individual products have 

varied according to the markets served and the 

specific items demanded in those markets (table 

2) 

Among the major commodity groups, lumber is the 

largest export, on the average accounting for 

about 45 percent of the total value of shipments. 

However, only panel products have increased since 

1980. The size of the miscellaneous group-primarily aillwork and prefabricated wood buildings-- 

was inflated in 1980 by a huge, one-time shipment 

of prefabricated housing to Syria. Roundwood 

shipments include logs, poles, and chips. 

Table 2.--Southern wood product exports, 1980 and 

1985. 

Product 1980 1985 

Roundwood : 

Softwood logs (mill. bd. ft .) 7 5 

Hardwood logs (mill. bd. ft.) 44 37 

Poles (thousand) 142 87 

Chips : ( thousand tons, dry) 424 6 7 

Europe, the Caribbean, and the Far East are the 

largest regional narkets for southern wood products (fig. 1). Most important within Europe are 

the nations in the European Economic Community 

(EEC). The Caribbean aarket includes the West 

Indies and Central America. Japan, Taiwan, and 

South Korea are the primary destinations in the 

Far East. The remaining markets are made up 

mostly of the oil-exporting countries in the 

Middle East, Africa, and South herica. 

The inaterial shipped to each of these markets 

ia different. In general, EEC nations have been 

major buyers of the principal hardwood exports 

(logs, lumber, and veneer) as well as selected 

southern pine products (plywood and rough-cut 

clear luaber). Wood chips for Scandfnavia and 

rough southern pine lmber have been the primary 

products shipped to European countries outside the 

EEC. The Caribbean is largely a market for softwood products, while the Par East is a southern 

hardwood market. Oil-producing countries in the 

Near East region import poles and prefabricated 

wood buildings. 

Lumber: (mill. bd, ft.) 

Softwood 274 1971 

Hardwood 67 86 

Panels: (mill. sq. ft.) 

Veneer, softwood 46 9 

Veneer, hardwood 336 206 

Plywood, softwood 6 2 179 

Plywood, hardwood 12 14 

Particleboard 11 2 

Miscellaneous: (mill. dollars) 

Cooperage 9 3 

Prefabricated buildings 101 2 4 

Other 30 25 

Roundwood 1 

I 

Southern log exports are atostly hardwood. Softmod log shipments have been relatively small, 

fluctuating between 5 to 10 millian board feet 

annually. Southern pine logs going to the 
Ssf twood %umber 3s sc2~tk"s r~0s& gmp~r~~nt 

soaid wood expcrt S.r?fcwc>:~~:~ -1.t.c:~pr ~xce.~," 

mainly southern pine, ~~~>~:~h a[?-:;:: 30 mi i 1 ion 

board feet of naneou:b~xn spec: e.; art: experced 

annually out of sout":~~c-r., y~~t;, stosc --f efje no>-- 

southerri f3~F~rac i -ra ,I.,*. rrr"::i)r:Gr ?, . . li +- ?ei "L .. <,< i i.,i -"r.-v 2 . .. ^- it-s:%~ cou~! pf~~ 

largely Clue td; Ei1-i pr~:;.~~; & J ":,.- c~~"~;~ rs 

southerv: sorts san;l 2% f ' : --- . >,-' = L:z;te-f- .je2;;ls2rf; 

at tkioae J"s@atfo3~ f-c"! 3 s1~2 3';. :>;:ff&rp s:: vgrz~~s 

species for specific afies* 

Wood- baaed panels 

Before soPt;wood ~~v~<~~;~ ekpuv-&s ~~ek ~ff 

- ~311 09 - -9wlwJ--->.+1~ id-A widdad ..-.- .~::.~eer wag gB.1~: prf~arv panel 

export, Impaar~ed fit-86 by the ~eeess.l:o:~ fn 

Europe, whfch aec~ounted fer 80 percent sf 1980 

sales, and then the sbrcng dollar, shj-pments slid b ,d ,- the 200 mj-3 lion-eausre-fo<>t j-evpl by 1992 

Ss'&s :.lave gp.:naj.rpf+R F3at sJRCe rkep, as rfs$nq 

s;aje% re "y-- ,>.* Sezsr ..-,-* ?:sva;i offset- 8 F--rrllp_;*- , ur tfYl 

~~~9 =L. - J .s,d,. -a ffi ex$-sr:c; rr; k:uyore , 
In addition to the griaary products, the South 

exports a varLety sf manufactured items or product8 0% secondary aanufacturing, Since there Is 

no cornon measure of solme, only the value sf 

shipeats is shorn in table 2a Of the nmetous 

products covered in this category of exports, 

cooperage sad prefabricated mod bufldkngs are of 

particular interest. 

Cooperage is one mod export that has steadily 

declined over a long period* In the late 1960's, 

cooperage aceounked for 20 percent of the total 

value of southern mod exports, ranking second 

oaly $0 southern pfne Imber. By 1985, it 

mounted to less than 1 percent of the total, 

men LafLtatBoa is factored in, the decline in 

real terns has been about 95 percent, 

Prefabricated mod bui%dLngs have replaced 

cooperage as kbe largeat miscellaneous product 

export. Shipents of daedular construction camps 

to the oil exporting countries became a noticeable itera following the first surge in oil prices 

in 1973. 33 1980, as menbt~ned earlder, there 

was also a huge shimen$ for goverment sponsored 

housing in Syria. 

More recently, however, the construction camp 

market has dried up rand a new market for rustic, 

recreation-oriented type structures has developed. 

For the South, shiments have been primar%ly for 

resort developewts in the Caribbean islands, but 

nationwgde there have also been shipents to Japan 

and other Pacific destinations, Iw any ease, the 

deatand is for panelized structures, gre-cut kits, 

and log homes, all of which can be skipped in containers. This substantially reduces handling and 

transportation costs, wZIIC~ can be excessive for 

modular units and mobile homes. 

OUTLOOK 

As noted at the outset, the dollares steady rise 

during the early 1980"s made southera wood products more expensive and less eoapetltive in 

foreign markets. Elowever, the more recent dollar 

decline Ps producfng signs of a turnaround, 

Mthough exports sf southern pine lurnber and plywood were down slightly overall in 1985 compared 

to 1984, ahipnaents in the third and fourth quarters were above the previous year, And for the 

first half of 1986, southern pine amber exports 

were up 14 percent and southern pine pl~od 

juaaped 59 percent* 

Wcbange rate developents will continue to 

affect the prospects for southern mod exports, 

but long-tern impacts are uncertain, It"s largely 

throqh exehange ratee that the relative competitive positfon sf different countries is established, Indeed, the head of &:Am-the General 

breement on Tariffs and Trade--recently stated 

that tariffs, on the average, are no longer iatportant obstacles to world trade, %at counts more, 

in his opinioe, are exchange rates for national 

currencies, mat lie8 ahead is difficult to say, 

but -re aad arose there are proposals calling for 

Lirn$te or ranges to be established to improve the 

current floating exchange system and prevent the 

wide fluctuations that have occurred over the last 

decade, 

matever the outcone, an tmportant point concerning exchange rates is how changes affect the 

markets that are signlfieant for southern wood 

products- POP example, based on recent currency 

shifts and considering exchange rare effects 

alone, the South should see increasing exports to 

Europe, stagnation or decline in the Catfbbean 

because of currency devaluatfons, and some additional growth in the Far East due to &he rising 

Japanese pea. These effects mag be enhanced or 

moderated by other factors, however, 

Exchange rates aside, the outlook far southern 

wood exports appears f avorable--prov%ded world 

economic conditions contfnue to improve, free 

trade policies prevail over protectionist forces, 

and the farest products industry mafntairas a 

comitment to expand expart markets, 

In western Europe, we should see opportunities 

to increase exprts sf clear southern pine Imber, 

southern pfne pl~wood, high-quality hardwood 

Lmber, and hardwood veneer, Two pf0d~et8 that 

have been important prevLous8p--hardwood logs and 

wood chips--may not recover due to reetrdctions 

relating to oak wilt disease and the pinewood 

nematode. Also, a European quota for softwood 

plywood 2% an obstacle, since a 10-percent tariff 

is levged an amounts that exceed the quota. But 

southern pinees share of the toral U.SB plywood 

exports continues to rfse; it reached 53 percent 

in 3.985 after averaging only 5 percent during the 

1970"s + 

In the Caribbean, future shipments sf southern 

softwood products ~$13. depend largely on the rate 

of econom2e progress Sn the area, the actions of 

competf ng softwood suppliers, and whether 

exporting programs are designed to meet the 

unBque charaeterBstBcs of the market. Mtholygh 

per ciapita incomes are relatively low in most 

countrfes, rap%dlg expanding populations are 

generating housing needs that support continuing 

imports due to the lack of domestic softwood 

resources- Polirtcal InstabflSty in Central 

Atnetica has disrupted the flow of lmber from 

that area, but Nonduras--our largest competitor 

in the region--fs expanding samilling capacity. 

Ghile also has been a recent supplier of Radiata 

pine lmber in the region, Thus maingaining or 

expanding southern shipments will require aggressive and inaovat8ve marketing efforts. 

The developing market for hardwoods in the Far 

%st has become important, and may become even 

mre so, mfs is somehat of a mixed bleeglng, 

however, since U.Se manufacturers must compete 

Kith furniture imprts that are coming back into 

our country, 

An encouraging development for future southern 

mod exports has been the involvement of industry 

trade asesciations and government agencies in the 

promotion of wood products in foreign markets. 

bsoeiat8ons suck as the Southern Forest Produces 
Association (SFPA), and the Arnerican Plywood 

Association (@A), in cooperation with the 

National Forest BPoducts Association and the Foreign &sicuftural Service, have developed progracns 

that will support increased sales to countries 

that offer opportuntties for export expansion. 

For example, both the SFPA and APA have conducted 

educational seminars in Caribbean countries where 

the use of softwood products could be expanded. 

In addition, SFPA placed a European representative in London in 1985, and more recently added 

a &ribbean representative in the Mminican 

Republ ice 

Success in developing foreign markets, however, 

may be detemined in large part by the extent of 

the comftment sf southern producers to exporting. 

In the past, interest in exporting has declined as 

doaestie markets improved, leaving U.S. producers 

with a reputation as unreliable suppliers. But 

progress is being made in changing this perception, Several recent articles in foreign trade 

journals have noted a grodng comttaent by 'uBsa 

producers to expottiprg, as well as a favorable 

view concerning our reliability coasgared to other 

world sources of wood prodaaets. 

ing up our recent export perfomance and 

the outlook: the South has not done as baddy as 

the initial averall value trends aap have suggested, since several product exports have 

remained strong; however, it may not do as well 

in the future as the popular reports about the 

decline in the dollar might lead us to believe, 

as most exchange indexes do not reflect a%$ of 

the currencies in markets important for southern 

wood products. Heverthelese, these are o?psatunities that should be pursued--both to more 

fully utilize the highest value potential from our forest and to help reduce the nat8on"s trade 

deficit. One thing is certain: the inrernaeional 

marketplace can no longer be ignored if southern 

forests and forest industries intend to aurvtve 

and grow in Codayes integrated world ecaaomy, 
Abstract .--Antong Latin American countries, Brazi 1 has the greatest 

potential for becoming a major force in world wood and forest products 

markets. The Amazon Basin contains 570 million ha, of forest land. 

Only 5% of this area's forest has been permanently cleared. Relatively 

little progress has been made in managing of existing forests in the 

hazon Basin, but in central and south Brazil much land has been planted 

with Eucalyptus and pine, Yields in successful Eucalyptus plantations 

have been very high, and plantations are supplying about half of the 

nation's wood needs for forest industries, steel manufacturing, and 

fuelwood, Between 1970 and 1980, the value of wood products exports 

from Brazil grew by 660%, and continued growth is anticipated, With 

major investments in forestry, Brazil could become a leading world 

supplier of wood and wood products, 

In traveling to the meeting in Atlanta, I flew 

from the city of Belem, at the mouth of the hazon 

Basin, to the city of Manaus, halfway up the 

Amazon. This flight took 2-1/2 hours by jet over 

nothing but forest broken only by the occasional 

cleared patch of land caused by shifting agriculb 

ture. One could continue and fly another 3 hours 

on to the city of Quitos, Peru, over the same conti nuous forest, 

While flying I was reading an article by World 

Watch stating that 40% of the forest would be 

cleared by the year 2000, That would mean clearing on the order of 16 million ha,/year and 

destroying 3 bill ion tons of wood. On the other 

hand, in the first 391 years of the hazon's 

settlement only 5% was permanently cl eared (NASA 

1986). Why so little clearing? I believe the 

answer is that it is difficult and expensive to 

clear this land, 

This forest, instead of being the legendary lung 

of the world, produces its own acid rain and 

gases, aiding the greenhouse effect (TNPAiNASA 

1986). The article about this largest and most 

controversial forest accepts no middle-of-the-road 

thinking on utilization and sustained productivity. 

One has to choose between destroying this forest 

and leaving it forever wild, 

Returning to the topic of the paper--it's rather 

difficult to cover South American forestry in this 

short time, Certainly many others are more 

qualified to cover the various topics, However, a 

unique opportunity and experience was afforded to 

me in that within a 12-year period, the project I 

was assoc i ated with: 

1, cleared land 

2. establ ished plantations 

3. harvested the tree crops 

4. produced high grade pulp 

5. replanted and coppiced a second generation 

6, and, not least of all, learned from lots 

of mistakes. 

In other words, short-rotation, high-yiel d 

plantation forestry is practiced in South America 

and is a resource potential we will have not only 

to accept but also understand as professionals. 

AS we discuss South America in more detail, 

keep in mind the prerequisites for development of 

the forest resources : 

1, land 

2, right amount and distribution of people 

3, infrastructure 

4, capital goods industry 

5, capital for investnent and operating, 

We tend to take these items for granted. However, they are limiting factors for many developing 

countries. 

FORESTRY IN SOUTH AMERICA WITH EMPHASIS ON BRAZIL 

In order to discuss forestry, we should first 

situate ourselves. 

I. Latin herica 

Latin herica is composed of 21 countries on 2 

billion ha. of land as compared to the remainder 

of North Ikneri,c,a with 2 countries and also roughly 

2 billion ha. of land. Latin America as a whole 

is a net importer of forest products (1980 net 

imports = $924 million). 

Honduras is the only net exporter in Central 

America (1980 - $4 million). The restraining 

factors in Central America are high population, 

limited land availability, other land use priorities (frui ticul ture and horticulture on better 

soils) , and shifting agriculture. However, some 

very good forestry work b3s been accomplished such 

as the work by CATIE and seed work on Caribbean 

pine and other tropical pines, A high priority 

has been placed on productSon of fuelwood for 

individual consumption, 

'Paper presented at Fourth Biennial Southern 

Si 1 vicul tural Research Conference, Atlanta, 

Georgia, November 4-6, 1986, 

2~onsu4~ant, Seneca, South Carol ina, 
II. South her13 

South herica is composed of 13 countries on 1.7 

hi1 1 ion ha, of land, Forest occupies 561 or 957 

million ha. of this land, The Arnazon Basin alone 

has 570 mil 1 ion ha, of forest la~d, In order to 

relate this--the forested land of the world today 

is estimated at 4 billion ha, 

South herica is a net exporter of forest products (net exports 1980 = $340 million), However, 

this figure is misleading because the only two net 

exporters are Chi 1 e and Brazi 1 (Net exports = $1.21 

billion). The three other large forest product 

producers, Argentina, Col umbia , and Venezuel a, are 

a11 net importers ($400, $100, and $222 mill ion, 

respect i vel y) , 

A1 1 have very active plantation forestry projects, including innovative ones like the Savannah 

Pine plantations in Venezuela and Columbia, The 

strongest growth has been in Chile (oldest forest 

products industry and plantation forestry) and 

Brazi 1 . Some countries 1 i ice Surinam accumul ated a 

great wealth of RKD in forest resources during 

colonial times but no appl ication, In general , population pressure, forest distribution, and other 

1 and uses have kept the other countries from developing thei r forest resources. 

111. Brazil . Past, Present. and Future 

General 

Brazil has more than 50% of the total land, 

forest land, and Forest products production of 

South Anterica and is now considered a world class 

exporter, In order to relate, let's look at some 

comparative statistics, 

- Brazi 1 - -- ----- United States850 mil, ha, Total Zand 937 mil, ha, 

570 mil. ha, Total forest 292 mil, ha, 

300 mi 1 . ha, Rrazi l i an Amazon 

135 mil. Prspul at ion 236 mi 1 . 200 mi 1, (ost, yr, 2000) 

142 mi 1 ./PI3 1970 roilndwood prod. 334 mi 1. /Q3 

245 mi 1 . /V3 1980 rorindwood prod. 390 mi l . /!15 

$5 bil. 1380 trade deficit 

$5 bil. 1983 trade surplus 

$100 bil, Foreign debt 

In some respects, I compare Brazil in its state 

of development to the United States in the early 

1950's dduri ng its resource expansion period, 

FOREST AND FOREST PRODUCTS INDUSTRY 

Development and growth in the forest products 

sector of Brazil can be shown by changes in the 

following statistics: 

-- 1970-1380 --- Units-- Change 

Sawn wood !I3 85% 

Panel products ~4 210% 

Wood pulp T 312% 

Paper T 116% 

Wood product imports $ 388% 

Wood product expo tt s iE 660% 

Net trade % 910% 

Of Rrazi 1 's total forest land, 570 mi 11 ion 

ha., 300 million ha, are unexploited reserves containing 45 hi1 1 ion N~ of wood in heterogeneous 

tropical forest, 

Although Rrazil stif 1 imports $250 nil lion of 

forest products, of which 50% is from the U.S., it 

has changed its status during the past decade from 

net importer to net exporter, The value of forest 

products produced annually is $1.2 billion, of 

which exports account for $916 mi 11 ion. 

The pulp and paper industry, for example, grew 

at a rate of lO%/year for the last 15 years. The 

value of exports in this sector was $180 mil 1 ion 

in 1979 and $514 mi 11 ion in 1983. Today, the 160 

small to medium pulpmills produce 3,600,000 T,/yr. 

of wood pulp, 

The energy forest often spoken of today is very 

real in Rrazil. In 1980, 20 million TOE (tons of 

oil eqcrivaleilt 1 in wood were consumed for energy, 

or 24% of the country's energy need. Rrazil has 

no coal to speak of, especially coking coal for 

the steel industry, Charcoal has always been used 

for this purpose, Most people don't realize that 

over 50% of a1 1 wood produced hy Rrazil ends yp as 

charcoal for the steel iqdustry, 30 million N /yr., 

and another 30 mi 11 ion F?"/yr, as di rect ftlel . 

The natural forest still plays a big role (50% 

of wood produced) in the forest product industry, 

a~d most of this i s i n the Amazon Basin area. 

Selective logging provides wood for more than 1200 

srnaf 1 to medium sized forest products industries. 

Not commonly known is the fact that oncecleared 1 and reverting to secondary forest is supplying much of the wood for the export industry, 

The more homogeneous pioneer species supply a 

better resource than the climax forest. 

FORESTRY DEVELOPMENT 

Plantation forestry was stimulated in 1916 

when the Rail road Company of the State of Sao Paulo 

sent a botanist to Australia to collect Eucalyptus 

seed. Many Eucalyptus species were tested and 

planted along the railways to provide fuel. As 

mentioned previously, the steel industry followed 

qoickly, establishing plantations for charcoal production. 

In the steel producing areas, the natural 

forest has been cut. Thus plantation forestry for 

charcoal and di rect energy consumption devel oped 

rapidly in central Brazil. 

In 1966 two events occurred, The Brazilian 

forest Service (IRDF) was established and the "tax 

incentive investment law for reforestation" was 

instituted. Very quickly, a few mill ion hectares 
were pf anted in Eucalyptus species and the first 

1 arge-scal e pine pl antat i ons (mostly 1 oblol ly and 

slash) were establ ished, 

Due to entrepreneurial manipulation of funds, 

lack of forestry knowledge, and the short time 

frame, a lot of these plantations were unsuccessful and a lot of money was wasted, However, some 

U.S. companies with pl antat i~n forestry experience 

and some very responsible Brazilian companies 

established a very good resource base. Most of the 

development occurred in the central South region. 

The pulp and paper industry had its strongest growth 

due to the effect of thfs investment incentive, 

Other laws were passed to stimulate and protect 

forest resources, Exampl e are: 

1. plant 4 trees for every M~ used by any 

i ndust ry 

2. 50% of any land ownership has to stay in 

natural forest, 

These two laws have had very little impact in 

reality. We won't discuss their failure. 

The Amazon region was and is the last to 

develop any sort of plantation forestry or rational management of the natural forest. Some futile 

attempts have been made with the natural forest. 

There are two significant exampl es of plantation 

forestry. The Pace1 project of planting tropical 

pines on savannah land has done quite we? 1 and 

today has developed 50,000 ha. The Jari project 

(controversial as it may be) has in a short time 

(18 years) proven and disproven many theories of 

plantation establishment in the tropics. 

Although economical ly the Jari project is 

debatable, biol ogicaf ly and forest resource-wise, 

it made a great impact on forest development in 

the tropics. It demonstrates the potential for 

forestry appl ications in other tropical envi ronments. 

FORESTRY PRESENT AND FUTURE 

Much development has taken place in the last 

15 years. Many exotics were planted, More + Eucaly tus species have been planted in Brazil 

t an in any other country. Both U.S. southern 

pines and tropical pines are being planted, Of 

all southern and related pines planted in the 

world, 101 are beinq planted in Brazil. Other 

exotic species, such as Gmel ina arborea and Acacia 

spp. have been commercia tecf , 

To date, 6,6 million ha, are in plantation 

management, of which 70% is Eucalyptus, 25% pine, 

and 5% other, In 1985, the plantation establishment schedule was f mill ion ha., with 55% 

Eucalyptus, 35% pine, and 10% other. Of the p1 antations established, 65% were with tax incentive 

money of the total sum of $180 mi 11 ion, 

The actual harvest in 1986, not counting the 

natural forest, is 80 million M' and 800,000 ha, 

Rotation ages vary from 3-7 year for Eucalyptus to 

8-16 years for pine Averase MAI per year can produce 15 to 30 M over the rotation, To state that 

25 ~~/ha,/~r, can be a fact would be no overstatement. 

With genetic 

~ucalyptus plan 

with a tendency 

improvement and crossing, some 

tations are producing 75 ~~/ha./~r. 

to reach 100 ~~/ha,/~r, Aswith 

most plantations in Brazi 1, these are ferti 1 ized, 

However, with these yields many si 1 vicul tural 

activities wi 11 be sound inve3tments. 

Brazi 1 ' s targeted roundwood harvest from pl antations in the year 2000 is 267 million bI3 yr. The 

year 2000 target a1 so includes a total of 14 million ha. in tree plantations, replanting 2 million 

ha. per year, and an employment of 1,1 mil 1 ion 

people in this sector, IF only 50% of this nearimpossible program is achieved, it will provide a 

resource base that will affect world trade, even 

though at last 50% will be consumed by the steel 

i ndust ry and by energy requi rement s , 

Brazil, in fact, has the necessary land, cl imate, and technological expertise to become a 

leading world supplier of wood and wood products. 

However, an annual investment of over $1 bill ion 

for forestry a1 one woul d be required. 

CONCLUSION 

There is no doubt that several countries in 

South America, due to their land base, climate and 

1 abor, could develop a strong forest industry, So 

far, only Brazil and Chile have developed this 

resource as an export potential. However, if the 

desire to develop this resource is matched with 

capability, some areas in South America could 

become a strong factor in world wood fiber markets. 

The two most limiting factors are capital 

availability and the existing socio-economic phi1 osophy. The phi l osophy of many devel oping 

countries is that forestry and forest industries 

are too primitive and have no place in a developed 

country except as a predatory aetivi ty. 

Certainly, pl antation resource development is 

a great achievement, However, the vast majority 

of forested hectares in Latin herica are still 

in climax forest and the greatest problem i s s t i l l 

how to manage and develop these forests rationally. 

In the Amazon Basin, this need is especially 

urgent, Qf the 570 mil 1 ion ha,, only 5% has been 

cleared so far, but pressure does exist for land 

utilization, The race to clear the forest for conversion to cattle pasture of the 1970% has luckily 

slowed down, Ths conversion and land use was an 

ecological disaster. Tree crops may be the answer, 

but how and what are the great questions that need 

an urgent answer, 
CURRENT AND FUTURE WOOD SUPPLY TRENDS IN AUSTRALIA, 

NEW ZEALAMD AND CHILE" 

Dr, W, R, J. sutton2 

Abstract,--Austral ia, New Zeal and and Chile are not significant wood producers. Their current combined harvest is only 12,3 million cunits - 

i .e. only 1/17th the combined annual harvest of the IlSA and Canada. A 

comprehensive review of their forest potential (mostly pl antations) shows 

that none of the three countries will increase production to the levels 

which have recently been pub1 ished. In all three countries, scope for 

production increases is limited before the mid 199flts. Australia will 

remain a net importer we11 into the next century. New Zealand and Chile 

between them could be producing an additional 7 to 10 mi 11 ion cunits per 

year by the year 2000, Given the low levels of these increases, and 

given the perceived market opportrlnities in Asia, the "threat" to North 

America from the forests of the South Pacific Rim is much less than many 

now believe. 

DISCLAIMER 

Mhere possible, factual material used in this 

paper is either referenced or the source identified, Decisions on which data source to use must 

introduce a degree of subjectivity. Interpretation of the data also involves elements of suhjectivity. All such decisions and interpretations 

are my own. They are not necessarily those of the 

company for whom I work, 

INTRODUCTION 

This paper summarises for Australia, New 

Zealand and Chile: 

(a) The present supply situation; 

(b) The structure of the plantation 

resource; and 

(c) Projections of future yield. 

The paper is an updated, but shorter version 

of a paper given in July 1985 in Vancouver to the 

Pacific Rim Markets for Forest Products (1985-2000) 

(Sutton 1985). 

Australia is the largest of the three 

countries. Its area is only fractionally less 

than the USA (excluding Alaska). Chile is much 

smaller - l/lOth the area of the USA. New Zealand 

is smaller st i 11. Its total area only equals the 

State of Colorado or about 1130th that of the 48 

contiguous States. 

PRESENT SUPPLY SITUATION 

The most recent wood harvest statistics are 

summarised in Table 1. The total harvest statistics for the USA and Canada are also given for 

comparison. By North American standards, the 

three South Pacific countries are not significant 

producers. USA production is around 30 times that 

of Australia, just over 48 times that of Chile, 

and nearly 50 times that of New Zealand. On present levels, the combined harvest of Canada and 

the USA is 17 times that of the combined harvest 

of Australia, New Zealand and Chile, 

Ninety-three percent of New Zeal and's wood 

supply comes from p1 antati ons of introduced trees 

(mostly radiata pine). In Chile 90% of the harvest 

is radiata pine. Australia's plantation production 

(again, mostly radiata pine) is as yet unimportant, 

supplying only 30% of Austral ia's total requirements - the balance comes from indigenous forests 

(mostly eucalyptus). New Zeal and and Chi 1 e are 

net exporters of wood. 

New Zealand exports just on 1.4 mill ion cunits 

(logs, sawn timber, chips, pulp and newsprint. 

Ch1 le exports about the same wood volume in much 

the same products. Australia is a net importer. 

Current industrial and trade levels are given in 

Table 2. Although these production and export 

levels are significant to the relatively small 

economies of New Zealand and Chile, neither 

country 'can be regarded as a significant producer 

or exporter at world level. Combined production 

totals for the USA and Canada for the major forest 

products is 50 times, or more, the levels achieved 

by either New Zealand or Chile. Australian 

imports, except in mechanical pulp, are in excess, 

and sometimes we1 1 in excess, of New Zealand's 

exports. 

FUTURE WOOD SUPPLIES 

There is widespread belief, almost fear, 

that the plantations of the three countries will 

soon mature and that significant, ever increasing 

volumes of wood wi 11 be placed on the world 

market, Many see these volumes as a real threat 

to the traditional forest products producers and 

exporters, especially in North America, 

' Paper presented at Southern Si l v i c u l t u r a l 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

ze as man Forestry Limited, Private Rag, Rotorua, 

New Zeal and 
Tab1 e 1.--Current annual wood harvest 

Wood Harvest (million cunitsfyearf 

PI antat i on 

1.0 0.7 1.7 5.3 

1.8 1.3 3.1 3.3 

1.8 1.5 3.3 3.7 

154.7 

56.8 

Notes and Sources: 

1 Saw1 ogs include peeler 1 ogs and logs for export 

2Valentine (1986) Table 16 

3From Table 33 of INFOR (1986) Plantation values are those for radiata pine 

Only. All other assumed to be indigenous. 

Table 2.--Current Production and trade of forest products 

Sawntimber (mi 11 ion bd ft) 

Wood chips for export 

(thousand BDU' s) 

Mechanical Pul p (thousand 

Chemical Pu1 p (thousand 

Newsprint (thousand long 

Source: Australia 1984 BAE, 1985 (*Green tonnes value converted to b.d.u,'s by multiplying by 0,444) 

New Zealand 1985 Valentine 1986 

Chile 1985 INFOR 1986 

(*Separate export figures for mechanical and chemical pulp are not available but almost all 

exports wi 11 be of chemical pul p,) 
The pl antat i on resources, age class 

structures, and projections of future supply for 

each of the three countries are reviewed below, 

CURRENT AREA OF PLAMTATIONS 

The most recent estimate of plantation areas 

is given in Table 3, 

Australia has just on 2 million acres of plantation forest. Si xty-seven percent is radiata 

and other pine species, mostly in Queensland, make 

up the bal ance. 

New Zeal and has just under 2.6 mi11 ion acres 

of plantation, 86% of which is radiata - 2.4 million 

acres, 

Chile is now reported to have the greatest 

area of plantations of the three countries - approximately 3 mi1 1 ion acres, Chile a1 so has the 

greatest area of radiata pine - 2-6 mil 1 ion acres 

- 87% of the country" total plantation area. 

Future wood avail akil ity from plantations 

depends partly on the rate of earlier planting 

(and restocking of felled p1 antations) and partly 

on other factors such as growth rates, commercial 

thinning and age at final Felling. 

RATES OF PLANTATION ESTABLISHMENT 

Figure 1 gives the annual planting rates for 

the three countries, For New Zealand, estimates 

begin from 1921, for Australia 1945, and Chile 

1952. 

New Zealand's plantings during the late 1920's 

and early 1930's aimed to provide increasing volumes 

of wood for the domestic market from the 1960's 

onwards. It was expected that by then supplies 

from the slow growing and largely non-renewable 

indigenous forests would be nearly exhausted. New 

Zealand's initial planting effort was not matched 

by the two other countries, However, during the 

1950's and 1960's Austral ia created new plantations faster than the other two countries 

(between 12,500 and 25,000 acres per year more). 

New Zealand's rate of new planting was usually the 

lowest of the three, hut there was 1 ittle difference between New Zealand 3.4 Chile, 

Through the 1950's the rate of new planting 

increased in all three countries. By the early 

1970's all were planting about 75,000 acres per 

year. Since the mid 19701s, there have been major 

differences, Over the last 10 years (1974-1983) 

Australia's average rate of planting was 91,000 

acres per year. Mew Zealand's was 113,000 acres 

per year and Chile's an impressive 205,000 acres 

per year, 

New planting is not the only contributing factor. New pl anti ngs are suppl enented by regenerated 

clearfell ing, This is particularly important in 

New Zealand because clearfell ing of the 1925-35 

plantings began in the 1950's and has continued 

ever since, 

A more realistic measure of the plantation 

resources, and their potential, is the age class 

distribution of the plantations. 

AGE CLASS DISTRIBUTION OF THE 

PLANTATION RESOURCE 

The published age class distributions of plantations as of the end of 1983 are given in Figure 2. 

A1 1 plantations are included for Australia. For 

New Zealand, figures for all plantations, and for 

radiata only are included. For Chile, only the 

radiata plantations are available, 

New Zealand has a significant area of trees older 

than 36 years. More than half of that is in species other than radiata pine (mostly Douglas fir), 

Nearly all the old radiata pine crop will be 

felled before 1990 to sustain supplies until 

significant areas of new pl anting become avai 1 able 

for harvest. 

Table 3,--Total Area of Plantations - 1984/5 

(million acres) 

1, BAE (1985a) Table 3, 

2, Valentine (1986) Table 9. 

3. INFOR (1986) Table 14. 
figure d ANNUAL EW KANVfNGS 

YEAR 

Figure 2 PLANTATION AGE-CLASS DISTRIBUTION 

36s 31-35 26-30 21-25 16-20 11-15 6-30 3-45 

AGE CUSS 
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The most questionable aspect of the projections is the predicted supply for the indigenous 

eucalypt forest, A1 1 projections, including the 

prel iminary 1985 estimates by FAFIPC suggest that 

the indigenous supplies will continue, with only a 

slight drop, well into the next century. 

However, at the recent 12th A1 1 Austral ia 

Timber Congress Conference (August 1986) several 

authorities clained that these levels could not be 

sustained. Between 1970 and 1984 environmental 

pressures have resulted in the withdrawal of 1.8 

mi 1 l ion acres of hardwood forest from production. 

The consequence of this, and other restrictions, 

will be to reduce saw and peeler log availability 

by the year 2000 by over one million cunits (i.e. 

to about the present supply level ) (Duncan 1996). 

I expect there would be the same proportional 

reduction in the pulpwood harvest (i.e. giving a 

total hardwood harvest of 1,8 mil 1 ion cunits by 

the year 2000), I a1 so expect that the hardwood 

harvest will decline even further after the year 

2006, 

It seems certain that Australia will remain a 

net importer until well after the year 2000. 

NEM ZEALAND 

Until a short time ago, the most authoritative, and comprehensive prediction of plantation 

supply was that sf Elliott and Levack 1981. They 

predicted that New Zealand has limited scope for 

i ncreasi ng production before 1990, The harvest 

could increase to around 8,5 million cunits after 

the year 2600, These figures have now been 

revised and new estimates (see Table 5) predict 

that the increases will be lower than formerly 

expected, The harvest just after the year 2000 is 

now expected do be 7,7 million cunits per year. 

Some authorities (e.9, Allison 1984) present evidence that suggests even the revised predictions 

are too optimistic, 

Very few pruned logs are currently available, 

Suppl ies will slowly increase and volumes are 

expected to exceed 1 million eunits soon after the 

year 2000. 

Major uncertainties make predictions di ff icul d: 

1. Mil 1 present level s of new pl anting he 

maintained, especially given recent Qvernment tax 

changes which positively discriminate against new 

forest planting and restocking? 

2. What rotations will be adopted, especially 

now that economics now favour longer, ratner 

than shorter, rotations? 

My view is that new planting rates wif l fall 

and that rotations wi 11 lengthen, Projected 

yields are therefore probably on the high, rather 

than the low, side, 

On one supply aspect there is total agreement, 

Suppl ies from indigenous forests wi 11 diminish to 

negligible amounts in the near future, 

New Zealand wi 11 be an increasing exporter of 

wood, but for the next 10 years any increase will 

be re1 ati vel y small . The big increase wi 1 1 not 

come until after the turn of the century and that 

depends on new planting rates being maintained. 

CHILE 

A1 though Chile has more radiata pine than New 

Zealand, the advantage is limited to stands less 

than 10 years old. Chilean forestry practice is 

going through a revolution. The emphasis is 

changing from pulpwood to sawn timber, Pruning 

was the exception 5 years ago, but it is now standard practice. To capitalise on this quality 

improvement, rotations wi 11 have to be lengthened 

from around 24 years to 30 years or more, 

In 1984 the Chileans pub1 ished conprehensi ve 

projections of future yield (see Table 6 for the 

predictions assuming rotation lengths of 24 and 28 

years). Our company has been looking at this (as 

have some Chi lean organisations) and our analysi s 

Table 5,--Projections of future wood supply 

New Zealand - Plantations Only 

Average Annual Yield Forecast for Periods 

(in million cunits) 

Product 1986-90 91-95 96-00 01-05 06- 10 

Pruned logs 0.1 0.4 0.7 1.2 1.4 

Total saw1 ogs 2.3 2.5 3.9 5,l 6.1 

Pul ppwood 0.6 0.8 1.0 1,4 1,5 

Total 3.0 3.7 5.6 7,7 9,O 

Source: tevack (1986) (pers. com) 
Table 6,--Projectic?s ID? Fi~tur-e wood Supply 

Chile - Radiata Pine Plantations Only 

- - - -- - 

-- %an A~8irral vrelds (mil 1 ion ccan-its) for periods 

83-85 86-88 89-91 92-94 95-97 98-00 01-03 04-05 

P4a1.r SSL* t 39s 2,9 2,9 3,8 3,7 a, 5 9,3 8-8 

Scenario Pul p 1-3 I, 6 2.7 3.5 3, i 5-3 4.2 

(24 yr r~tdti~n) 

Toea l 4, Z 4.5 6,s 7.2 7-6 14,6 13.0 13.8 

loeals for 

28 yr rotation 

scenario Total 3-5 3,8 4-1 5-0 6,s 3,3 ii,9 f9,7 

Source : 

GOKFO- Valdes For the 24 year rotations from the table accompanying Graph No, 2 (page 451, 

INFOR 1984 Values for 28 year rotation from the table accompanying Figure No, P (page 561, also 

total value for 2004-06 on a 24 year rotation, 

leaves us in no doubt that the published Chilean 

projections are very optimistic, Our own projections are not yet complete but they suggest that 

the Chilean yield far the rest af this century 

will be very similar to that dhich Levack (1986) 

now forecasts for Y"u"e~ Zeal and, Chile wi;i 1 have to 

wait until the next ceQtt~ry before she can capital i se on her expanded p5 anting programme, 

The data presented above is based on projections. There are doubts about many aspects and 

about what will actual ly happen, Some important 

aspects are: 

Data Accuracy 

There are doubts about ðer a17 the plantations claimed to exist do in fact exist, Yield 

forecasts, despite recent advances, are not a1 ways 

reliable, Silviculture alone can affect the 

volume produced in New Zealand by 25% or more. 

The trend to lower stockings will improve financial returns but lower overall yields, 

Tree Oualftv 

Rarefy is tree qua1 iey taken into account in 

projec"to~s. Siltb;iltiltl~re, site and genetics can 

affect tree sine a04 q11al";ty and therefore, end 

use, Apart Prom a d4vision betdeen sawlogs a~d 

puf pwood this aspect is cje~e~al ly ignored in a9 1 

projections, Qua1 i ty land eccnom.ic) cons4 dera"cons 

have major imp1 icaeions on rotation le~gth, The 

trend is towards longer rotations, 

appear to have Seen given the consideration it 

warrants, 

Locational and Industrial Considerations 

Some plantations are remote and may not be 

harvested when pf anned, Phis could affect Future 

projections, Some industries (say, a new 

pul pmi 11 ) need continuous large suppl ies of raw 

material before they ca? begin production, 

Capital , energy, infrastructure, and markets have 

to be organisen before new ventures can begin, 

These factors will tend to delay harvest, These 

projections usual ly ignore forest ownership, 

another factor wki ch could delay devel opnent . CONCLUSIONS 

The evidence does nct support a be1 ief that 

the three South Pacific Rim countries are soon to 

produce vast additional volumes of wood which will 

flood the world market, All three countries 

appear to have limited potential increases in 

production before 1990, Even by the year 2000 the 

increased vof ume production potential may not be 

great, 

Australia will be a net importer sf wood well 

beyond the end of this century, 

Even when the p~terrtial prodirc"r,ion for Yew 

Zealand and Chile are cnrnhi?ed, the additional 

volume available in the year 20C0 will probably 

only be in the range of 7 to 10,s million cunits, 

X repeat that I believe the real threat to 

northern hemisphere producers from southern 

Envi ronmental - Pressure hemisphere pf antati~ns is much more from the technology of plantation management, than from 

This wi 19 certainly infl uexe wood avail abil ity increased volumes of )OW cost wood, 

from indigenalis forests in Adscral fa arid, to a 

lesser extent, hew Zeala~d, It may influence That plantation technology offers muck more of 

plantation supplies as well, This aspect does not an opportunity than it does a threat, 

THE PULP AND PAPER INDUSTRY IN THE NORDIC COUNTRIES 

IN AM ERA OF IMCREASING INTERNATIONAL COMPETITION" 

Kari pesonen2 

INTRODUCTION 

I am very pleased to have this opportunity to 

discuss the pulp and paper industry in the Nordic 

countries, During the last ten to fifteen years, 

the global pulp and paper industry has experienced 

considerable changes due to fluctuating exchange 

rates, increasing oil prices, new producers and 

consumers, etc, 

The Nordic countries, where the importance of 

the pulp and paper industry sector is among the 

highest in the world, have been strongly challenged 

to meet these changing conditions in such a manner 

that this key industry could survive and even 

prosper. 

I will divide my presentation into five 

parts : 

1 Nordic countries and the role of forest 

industries to their economies. 

2 Role of the Nordic countries in global 

pulp and paper markets. 

3 Changing international market conditions 

for pulp and paper products. 

4 Changes in pulp and paper industry structure in the Nordic countries. 

5 Competitiveness of the Nordic pulp and 

paper industry. 

I will concentrate on Fin1 and, Sweden and 

Norway. Denmark is a part of the European 

Economic Community (EEC) and has completely different resources and problems, I will also leave 

Iceland out as its raw material base does not support the production of pulp or paper products, 

Additional ly, I will concentrate on pulp and paper 

industry only as the importance of this sector 

within the forest industries in the Nordic countries today is clearly most important, 

COUNTRY PROFILES FOR THE NORDIC COUNTRIES 

Land and People 

The expression, Mrdic countries , usual ly 

refers to Finland, Sweden, Nsrway, knmark and 

Ice1 and. The often used expression, Scandinavia, 

actually does not include Finland which only 

be1 ongs to the expanded expression Fenno-Skandia. 

Fi nl and, Sweden and Norway, where the production 

of pulp and paper in the Nordic countries is concentrated, are located between 55 and 70 degrees 

Northern latitude, As can be seen from Figure 1 

this geographical location suggests a c1 imate 

hardly suitable for the production of forest products. The influence of the warm Gulf-stream, 

however, has resulted in a climate far warmer than 

geographi cs a1 one suggest. 

To give a general idea of the Nordic countries, 

some basic indicators of the people and the country have been summarized into Table 1. In this 

table, the population in millions, GDP in USD billions and forest area in millions of hectares are 

presented. To make comparisons somewhat easier 

also, some per capita figures are presented. 

o The total population of the Nordic countries 

is only some 17 million, but the land area is considerably large (Sweden is the fourth largest, 

Finland the fifth, and Norway the sixth largest 

country in Europe). As a result, the number of 

inhabitants per square kilometre is low (only some 

20 compared to 163 in the EEC countries). For 

reference, the USA has slightly higher number than 

the Nordic countries with 25 (31 excluding Alaska) 

but Canada has one of the lowest figures in the 

world with only 3 inhabitants per square kilomet re. 

o The Nordic countries have a very high standard of living measured as GDP per capita. It was 

12 000 IJSD in 1984 compared to 7000 USD as the EEC 

average. For reference, the income per capita in 

the USA was about 16 000 USA and in Canada some 

13 000 USD. The magnitude of the total GDP cornpares roughly with Canada. 

o The forest area in the Nordic countries is 

considerable compared to population and the average 

forest area per capita is 3 hectares compared to 

less than 0.2 in the EEC countries. For reference, 

the forest area per capita in the USA is about 1 

hectare per capita but in Canada a substantial 12. 

The total forest area in the Nordic countries (52 

million hectares) exceeds that of the EEC-10 (34 

million) but is small compared to the USA (298 

mill ion) or Canada (314 mil 1 ion), 

The above facts about the Nordic countries can 

be summarized as follows: 

o a small population with a large land area 

o high standard of living 

o a lot of forests. 

1 Payer presented at Southern Silvicultural 

Research Conference, Atlanta , Geory i a, November 

4-6, 1986. 

'~aakko Poyry Oy, P.O. Box 16, Kautintie 3, 

00441 He1 si nki , Fi nl and 
SOVIET UNION 

Figure 1 

PROFILES OF THE NORDIC COUNTRIES COMPARED TO 

WESTERN EUROPE AND NORTH AMERICA 

TOTAL 

POPULATION TOTAL GDP FOREST AREA 

(MILLIONS) (BILLION USD) (MILLION HA) 

NORDIC COUNTRIES 17 21 2 52 

USA 239 3841 298 

CANADA 25 342 31 4 

INHABITANTS/ INCOME FOREST AREA 

SQUARE KI LOMETRE USDfCAPITA HAlCAPlTA + 

NORDIC COUNTRlES 16 12 000 3.0 

USA 26 16 000 1.2 

CANADA 3 13 000 12.4 

Table 1 
Role of Forest Industries to the Economy 

Due to their small population, the manufacturing industries in the Nordic countries soon found 

their domestic markets 1 imi t i ng and were forced to 

seek export markets, This trend has continued and 

is clearly seen in Figure 2 where the share of 

exports as percent of the GDP for the herdic countries is presented in 1970 and 1384, 

o The share of exports as percent of the GDP 

in the Nordic countries is very high and has grown 

clearly since 1970. 

o The share of exports is highest in Norway 

where they accounted for almost ha1 f of the GDP in 

1984, For Norway, however, crude oil has had a 

decisive role in this development. 

o In Finland and Sweden export revenues 

accounted for more than 30 X of the GDP in 1984 

compared to some 25 % in 1970. 

o For reference, in the USA the share of 

exports is less than 10 %, but in Canada exports 

accounted for almost as much as in the Nordic 

countries. 

Looking closer at the exports (Figure 3) in 

1970 and in 1984 it can be concluded that: 

o The share of forest products as percent of 

total exports has declined in the Nordic iountries. 

This does not mean, however, that forest industries 

had not grown but rather that other industries such 

as the metal and chemical industries in Finland and 

Sweden and the oil industry in Norway have simply 

grown faster. 

o The importance of the forest industry is 

highest for Finland where it accounts for almost 

40 % of export revenues. En Sweden, the share of 

forest products is today already less than 20 % and 

in Norway only some 5 Z of total exports. 

o For reference, the share of forest industry 

of total exports in the USA is only 3 % but in 

Canada it accounts for almost 15 % of all exports. 

The role of the forest industry in the Nordic 

countries can be summarized as follows: 

o The importance of forest products to the 

economy is clearly biggest for Finland, For 

Sweden, it is today the number two industry and 

for Norway its importance is relatively small. 

o Export of paper in the Nordic countries has 

grown faster than that of other forest products 

making it the most important export product of 

the Nordic forest industry today, 

ROLE OF THE NORDIC COUNTRIES IN 

WORLD PULP AND PAPER TRADE 

Share of Markets and Main Products of the Industry 

The share of the Nordic countries of world 

production of pulp and paper is iilustrated in 

Figure 4: 

o The share of the Nordic countries is about 

14 % in pulp production and 8 % in paper production. 

o North herica has clearly the highest 

capacity of both pulp and paper. 

o The share of the Nordic countries of pulp 

exports is about 24 % and 31 % of paper exports, 

o North herica dominates exports of market 

PU~ P*

o Mestern Europe is an important exporter of 

paper with a 24 % share of world exports. 

The importance of the Nordic countries is considerably bigger in world exports than in world 

production, Together with North America, the 

Nordic countries still dominate exports of market 

pulp and together with North America and Western 

Europe the exports of paper, 

The production of main pulp and paper grades 

in the Nordic countries is presented in Figure 5: 

o Sweden is the biggest producer of pulp 

within the Nordic countries with a production of 

some 9 million tons in 1984 followed by Finland 

with close to 8 million tons, 

o Norway is clearly least significant with a 

production less than 2 million tons in 1984, 

o Bleached kraft pulp is the most important 

chemical pulp for Finland and Sweden. Sweden produces mostly softwood kraft whereas Finland also 

has a sizeable hardwood kraft production. 

o The share of other chemical pulps including 

unbleached kraft and sul phi te pul ps is considerable in Sweden due to higher share of industrial 

paper grades of total paper production but small 

in the other Nordic countries, 

The paper production in the Nordic countries 

can be summarized as fof lows: 

o Finland is the biggest producer of paper 

with a production of 7.5 million tons in 1384 

followed by Sweden with 7 million tons, 

o The production of paper in Norway was less 

than 2 million tons in 1984. 

o The share of newsprint of total paper production in Finland and Sweden was about 20 X and 

equivalent to over 1.5 mill ion tons for each in 

1984, In Norway the production of ne~sprint was 

only some 0.8 mil 1 ion tons but accounted for 60 Z 

of total paper production. 

o Printing and writing papers accounted for 

close to 50 % of paper production in Finland with 

3,5 mill ion tons whereas in Sweden their share was 

only about 20 % with st ightly over 1 mi 11 ion tons, 

o The share of industrial papers including 

sack paper, linerboard bleached board, etc, 

accounted for over 50% of paper production in 

Sweden with close to 4 mi1 1 ion tons of production 
SHARE OF EXPORTS OF TOTAL GDP 

iN THE NORDIC COUNTRIES 

Figure 2 

SHARE OF FOREST INDUSTRIES OF TOTAL EXPORT 

EARNINGS IN THE NORDIC COUNTRIES 

SOUD VVBOD 

PRODUGTS PULP PWER AND BOARD 

FINUND SWEDEN NORWAY (USA) [CANADA) 

Figure 3 
OTHERS 

NORTH 

MERICA 

JAPAN 

EASTERN 

EUROPE 

WESTERN 

EUROPE 

SHARE OF NORDIC COUNTRIES 

IN WORLD PUW AND PAPER MARKETS 

- X OF TOTAL - ?OD 

NORDIC COUNTRIES 

Figure 4 

PRODUCTION OF PULP IN THE NORDIC COUNTRIES 

IN 1985 M CWANISL MD S~MI-CHEMIW SO&%~#~& H*RBPHE& dt%F& EzzJ 

PRODUCION OF PAPER IN THE NORDIC COUNTRIES 

IN 1985 

NRYSWllM PRlMlNG AND INDUSTRW. WRITING GRADES 

ezz 

Figure 5 
in 1984. In Finland their production total led 

about 2.5 mil 1 ion t~ns but was only about 30 % of 

production, 

Finland and Sweden are clearly the most important producers of pulp and paper among the Nordic 

countries, The product mix between the Nordic 

countries for both pulp and gaper differs considerably as Finland produces printing and writing 

paper, Sweden mostly industrial grades and Norway 

newsprint. Because the demand for pulp in the 

Nordic countries is mostly created by the 

countries own paper mills it is logical that the 

differences in produced pul p grades result mainly 

from differences in paper mix, 

MAIN MARKETS FOR WLJ A$.ID PAPER PRODUb3nON 

OF THE MORDIC COUflRIES 

PULP BjIRN EWIM 

Main Markets 

The main markets of pulp and paper for the 

Nordic countries are presented in Figure 6: 

o The majority of the pulp production in the 

Nordic countries is used in integrated paper 

mills. 

o The volume of exports is about 4-83 mil 1 ion 

tons representing about 25 % of total pulp 

production. 

o Western Europe represents the main market 

for pulp exports with a volume close to 4 mil 1 ion 

tons or about 88 % of exports, 

o Other markets for pulp are marginal with a 

total volume of about 1 mil I ion tons. Oceania and 

Asia are most important among them. 

The paper markets can be summarized as follows: 

o Domestic markets account for only 21 % of 

total production of paper, 

o Also for paper, Mestern Europe is the most 

significant export market with an export volume 

close to 9 million tons or 72 % of exports. 

o Australia and Asia are the second most 

important export markets for paper from the Nordic 

countries with a volume sf 1.5 million tons. 

o North herica and especially the USA has 

increased in importance considerably during the 

last years and this market today takes 6 % of the 

paper exports with a volume close to 1 million 

tons, 

The markets of the Nordic pulp and paper 

industry can be summarized as folf ows: 

o The majority of the pulp production is consumed domestical ly and the remainder is exported 

to Western Europe. 

o Domestic markets only absorb 20 % of the 

paper production and the majority of paper is 

exported to Western Europe, Markets outside 

Western Europe have, however, increased in import ance. 

WESTERN 

D0Mf4s?li 

TOTAL PR0DUC;TION l8-7 MIL TO% 

PAPER 4 

TOTAL PROWCTlON 16.4 MIL TONS 

Figure 6 

Main Competitors 

. The competitors of the Nordic countries are 

discussed mainly on the Western European markets 

as this market clearly dominates in importance for 

both pulp and paper exports. 

The market shares of main competitors for 

selected pul p and paper grades are presented in 

Figure 7 and Figure 8, The Following can be 

concl uded : 
OTHER 

MARKET SHARE OF BEACHED SOFNVOOD 

IN THE EEG 

Figure 7 

MWEI SMRE OF NEWSPRINT 

IN THE EEC 

MKn SMRE OF BtEACHED HARDWOOD WWT PULP 

IN THE EEC 

nN 

o The Nordic countries together with the USA 

and Canada are the most important suppliers of 

softwood chemical pulp to Western Europe, The 

Nordic countries and especial ly Fi nl and and Sweden 

are main competitors to each other, 

o For bleached hardwood kraft pulp the domestic supply from Spain and Portugal is the most 

important. The Nordic countries compe.te also 

against each other and Canada, USA and Rrazi 1. 

o All Nordic countries are important producers of newsprint and supply about 50 % of the 

Western European demand. The competition stems 

1 argely from domestic producers but also Canada 

is an important competitor in Western Europe. 

MARKFT SWAAE OF PRlNnNG AND WRITING PAPERS 

IN THE EEC 

Figure 8 

o For printing and writing papers, Finland 

and Sweden compete against each other for some 

grades but are re1 atively small compared to the 

main competition from local producers. 

CHANGING INTERNATIONAL CONDITIONS 

The markets For pulp and paper like the whole 

world trade have experienced considerable changes 

during the last fifteen years, bong the most 

important changes affecting the pulp and paper 

i ndust ry have been : 

o fl uctuat i ng exchange rates, 

o increasing energy prices. 

o new producers, 
Exchanae Rates 

The exchange rates of world currencies 

remained fixed until 1971 when the Bretton Woods 

agreement was signed (Figure 9). lJntil then the 

US dollar was fixed to the price of gold, and the 

exchange rates of foref ;n carrencies were adjusted 

periodically only if there was a need for it, 

Since, the exchange rates started to fluctuate in 

1971: 

o The US dollar depreciated against the 

European currencies up until 1980. This had a 

negative influence for the pulp and paper industry 

in the Nordic countries as most of their products 

were traditionally invoiced in US dollars. 

o Since 1980, the development was reversed 

and a dramatic appreciation of the US do1 lar was 

experienced in the world. This was very beneficial for the pricing of the Nordic pulp and paper 

producers and improved the cost competitiveness to 

such extent that exports to the US markets became 

economical ly feasi bl e. 

o Since 1985, the US dollar has, however, 

again reversed its development and has depreciated 

against most industrial i zed currencies and has 

again applied cost pressures for the pulp and paper 

producers in the Nordic countries. 

Energy Prices 

The prices of energy have experienced dramatic 

changes during the last fifteen years influencing 

the whole world economy. We have all in a very 

concrete fashion experienced the effects of rising 

oil prices in the 1970's. The rising oil prices 

have a1 so influenced the price development of other 

fossil fuels such as natural gas. 

Of the Nordic countries, Finland and Sweden 

have no oil , gas or coal deposits of signi ficance 

within their boundaries while Norway has developed 

big reserves of oil in the North Sea. The rising 

oil prices have consequently had an opposite 

effect for Norway than- for Fin1 and and Sweden. 

The pul p and paper industry which is an energy 

intensive industry was strongly challenged by the 

rising oil prices both in Finland and in Sweden. 

The dramatic price development of crude oil since 

1973 is il lustrated in Figure 10 in US do1 lars: 

o The oil price in US do1 lars increased a 

substantial 42 % p.a. during 1974-1980 to 35 

USD/barrel , 

o The appreciation of the Nordic currencies 

against the US do1 lar partly reduced the effect up 

to 1980. 

o Since 1980, the price of oi 1 decreased 

sl ightly to USD 28/barrel , but the appreciation of 

the US dollar created still strong increases in 

1 ocal currencies, 

o Since 1985, the dramatic drop in oil prices 

together with a depreciating US dollar have compl etely reversed the situation. 

EXCHANGE RATE DWELOPMENT OF NORDIC 

CURRENCIES AGAINST THE US DOLIAR 

RM SEK NOK 040 

--- -------- ..*.......-. 

Figure 9 
CRUDE OIL PRICES 1973-1986 

ARABlAN UGHT AP134,SPOT ROTTERDAM 

- YEAR - 

Figure 10 

Rew Producers 

The supply of both pulp and paper has experienced considerable changes during the last fi fteen 

years. New producers have appeared on both domestic and export markets of several grades changing 

the overall market picture. 

This development has been especially dramatic 

for bleached hardwood kraft market pulp. In Figure 

11, the development of the market shares for main 

producers of this grade are illustrated during 

1965-1985. 

The fol 1 owing concl usions about the devel opment can be drawn: 

o Producers in Latin Ilnerica, mostly Brazil 

and in the Southern Europe, in Spain and Portugal, 

have initiated a massive production of bleached 

hardwood kraft from eucalyptus p1 antat i ons since 

the 1970's. This wood which produces a low cost, 

high quality pulp has had a tremendous impact on 

the global pulp markets. 

o The share of the ~aL'in American and Southern 

European producers today is close to 40 % of the 

market for bleached hardwood pulp compared to 

slightly over 10 X in 1965. 

o The North American producers have kept 

their market share whereas producers in the Nordic 

countries have integrated into paper production 

and have seen their 35 % market share in 1965 

decl ine to about 15% in 1985, 

The production of chemical market pulp where 

the cost of wood raw material is decisive for profitablilty has begun its shift to southern regions 

where huge pl antations guarantee avail abil ity and 

the favourable cl imate results in astonishingly 

WORLD PRODUCTION OF BLEACHED SULPHATE 

HARDWOOD MARKET PULP 

Figure I1 
fast groltPGh and consequently low cost of wood. 

This trend will continue in the years to come as 

production is expanded and new appl ications for 

eucalyptus pulps are developed. This will place a 

strong challenge for the market pulp producers 

in the qorthern parts of the world. 

CHANGES IN THE NORDIC PULP AND PAPER INDUSTRY 

Markets 

and woodfree fine paper is presented. As previously discussed, the Nordic pulp and paper industry 

has faced increasing competition for products where 

the share of fiber cost is high such as chemical 

pulp, This has forced the industry to integrate 

into papermaking, to develope new products such as 

SC (supercalendered) papar and to invest in products where the cost competitiveness is better. In 

Figure 14, the share of market pulp of total pulp 

production is demonstrated for Finland and Sweden: 

As previously discussed, the Nordic pulp and 

paper industry has its main market in Mestern 

Europe for most pulp and paper grades. Due to 

changing international conditions, however, also 

other markets have become attractive. Good example of this has been the rapidly growing demand 

for pulp and paper products in the Asia. Another 

example is the US market which became attractive 

due to the appreciation of the US dollar since 

1980. In Figure 12, the exports of the Nordic 

countries to the USA are illustrated during 1970- 

1985, The annual growth rate in the 1980's has 

exceeded 20 %, The fol 1 owing can be concl uded 

about the development : 

o The increase in exports has been very rapid 

and the l eve1 today is close to 0.8 mi 1 1 ion tons. 

o Newsprint exports have reached a level of 

200 000 tons in 1985, Norway and Sweden are the 

major forces behind increased exports of 

newsprf nt . o Exports of printing and writing papers to 

the USA were close to 0.5 mill ion tons in 1985, 

Finland is the major force for these grades constituting close to 80 X of the Nordic exports. 

o The exports of industrial grades from the 

Nordic countries have remained at marginal levels, 

most of them coming from Sweden. 

It must be, however, remembered that although 

the Nordic producers constitute a considerable 

portion sf the off-shore imports, they are still 

small compared to the total paper imports of close 

to 9 mill ion tons or total paper consumption of 65 

mil 1 ion tons in the USA, For certain higher 

quality paper grades where the market volume is 

1 imited the importance of the Nordic producers 

has been of significance, 

It remains to be seen how the recent depreciation of the US dollar against the Nordic currencies 

will influence export incentive to the USA. Several Nordic pulp and paper companies have expressed 

their determination to stay on the US markets and 

the export continues at about the same rate, 

although certain grades such as SC and LWC paper 

have seen a slackening of demand, 

Production 

Product Mix 

In the production of pulp and paper, the share 

of fiber cost of total costs varies considerably 

between di fferent grades as i 11 ustrated in Figure 

13 where cost structure of bleached softwood kraft 

o The share of market pulp of total pulp production has decreased significantly during the 

last twenty years. 

o Finl and has decreased its dependence on 

softwood market pul p from 64 & in 1965 to 28 X in 

1985 and Sweden from 85 X in 1965 to 65 X in 1985. 

Sweden is thus still more dependent on softwood 

market pulp. 

o In hardwood pulp, Finland has decreased 

dependence from 85 X in 1965 to 48 X in 1985, For 

Sweden, the development is even more dramatic as 

the dependence on hardwood market pulp in 1965 was 

97 % compared to 57 % in 1985. A1 so in hardwood 

pulp, Sweden is more dependent on market pulp than 

Fi nl and. 

In addition to higher degree of integration, 

the Nordic countries have invested in paper products where the share of expensive fiber is lower. 

In Figure 15, the product mix of paper production 

in Finl and and Sweden is demonstrated: 

o The share of cultural papers including 

newsprint and printing and writing papers has 

increased in both countries. 

o The share of cultural papers has increased 

considerably in Finland, from 53 % in 1965 to 

67 % in 1985. Sweden which has traditionally had 

a lower share of cultural papers has also 

experienced the same devel opment . The increase 

has, however, not been as dramatic as in Finland, 

from 37 % in 1965 to 42 % in 1985. 

The pulp and paper industry in Finl and and 

Sweden have si gni f i can1 ty decreased thei r dependence on market pulp by integrating into papermaking. Both countries, and especially Finland, 

have changed their product mix in the increasing 

competitive markets and have invested heavily in 

the production of cultural papers, and consequently they account for the majority' of paper produced 

in Finland today and approach the 50 X market al so 

in Sweden. 

Production Inputs 

The production costs of pulp and paper differ 

considerably by product, but usually the most 

important cost elements are fiber, energy and 

1 abor, 

Fiber 

Due to the Northern geographical location, the 

growth of wood in the Nordic countries is clearly 

slower than in most competing regions. This is 
PAPER EXPORTS FROM THE NORDIC COUNTRIES 

Figure 12 

COST OF MAJOR PRODUCTION INPUTS 

TOTALGBSTDEUVERED TO CENTRALEUROPE 

Figure 13 
SHARE OF MARKET PULP IN NORDIC COUNTRIES 

- PERGENXE OF TOTAL PRODUCTION (BLEACHED SUPHATE) - RNNISX RNNISH SWD1SH WEMSH 

WARDWOOD SOmW XARDWOOD SCtWWD 

Figure 14 

SHARE OF CULTURAL PAPERS IN PAPER PRODUCTlON 

IN NORDIC COUNTRIES 

FINMND SWEDEN 

............ 

1975 1980 1905 

Figure 15 

SHARE OF OIL OF TOTAL HEAT GENERATION 

IN SWEDEN 

RME PAPER SACK KRAFT 

e-BL-BIIB- .......... f. 

PURCHASED POWER PRICE 

REGIONAL AVERAGE 

Figure 18 
AVERAGE CAPACIW OF NEilVLY INSTALLED 

PAPER MACHINES 

NORDIC 

COUNTRIES 

OTHER WESTERN 

EUROPE USA CANADA 

---.-_ern_ '...*....I.. 

. . . * 

Figure 19 

NUMBER AND AVERAGE OUTPUT OF PULP AND PAPER 

COMPANIES IN THE NORDrC COUNTRIES 

NUMBER OF AVEME OWPUT 

COMPANIES PER COMPANY 

Figure 20 
COMPETITIVENESS OF THE NORDIC PULP 

AND PAPER INDUSTRY 

The cmpetitiveness of any industry can be 

measured in several ways, but in industries where 

the products do not substantial fy differ from one 

another the comparison of manufacturing costs is 

one of the most interesting ones, 

Size of Paper Machines 

As previously discussed, the pulp and paper 

industry in the Nordic countries has invested in 

bigger paper machines than the competing regions, 

This is cleariy illustrated in Figure 21 where the 

average size of existing paper machines for selected countries is presented: 

o Finland has the biggest existing paper 

machines with an average capacity of over 70 000 

tons per year followd by Sweden with over 60 000 

tons. This is very high compared to EEC where the 

average size still is less than 20 000 tons per 

year. 

o Norway has clearly smaller machines than 

Finland and Sweden. 

o Canada and the USA also have big machines 

in international comparison with average capacities of over 50 000 tons. 

In these figures each graph represents a region 

and the y-axis shows costs of producers placed in 

ascending order whi l e the x-axis shows cumulative 

tonnage of each region, 

For bleached hardwood kraft fol lowing can be 

concl uded : 

o Portugal and Brazil have about 30 % lower 

costs than Finland. 

o &st mills in the US South have also lower 

costs than the Finnish producers, 

For uncoated rroodfree paper the conclusions 

are fof lowing: 

o The integrated mills in Finland and Sweden 

are competitive in Western Europe. 

o The integrated mil 1 s in Sweden appear to 

have the lowest costs. 

o The unintegrated mil Ts in the Nordic 

countries have higher costs than most other 

producers. 

The cost competitiveness of the Nordic producers clearly illustrates that even the big, 

modern production units cannot compensate the 

substantially lower wood costs of the Southern 

producers for hardwood pulp and the cost competitiveness against them is weak, 

The cost competitiveness i.e. manufacturing 

costs and delivery costs to Western Europe of the For uncoated woodfree paper the situation is 

Nordic producers for two di fferent products, reversed and the integrated producers in Finland 

namely bleached hardwood kraft pulp and uncoated and Sweden have a clear cost advantage against the 

woodfree paper are presented in Figures 22 and 23. unintegrated producers of the EEC. 

AVERAGE CAPACIN OF EXISTING PAPER MACHINES 

Figure 21 
BLEACHED MARKET PULP,HARDWOOD SULPHATE 

MANUFACT. AND DlSTR COSTS TO WESTERN EUROPE.COST LEVEL 1986/11 

WOODFREE UNCOATED PAPER 

MANUFACT. AND DlSTR COSTS TO WESTERN EUROPE.COST LEVEL 1986h1 

WESTERN EUROPE 

NON-IrnWJED 

---- 

WESTERN EUROPE 

INTEGRAJED 

--- 

HNLAND AND SWEDEN %MI 

NON-MEGRATED - 

SWEDEN IMFGRATU) 

--. 

FINMD 

~MEGRArn - 

--threw-KXK)tlatlgm48W462 

Figure 23 
COMCLUDING REMARKS 

The Nordic countries where the importance of 

the pulp and paper industry to the national economy is among the highest in the world have been 

strongly challenged to meet the changing international conditions during 'the 1 ast fifteen years, 

The industry has gone through several changes 

concerning industry structure, energy efficiency , product mix, markets etc, bong the most important changes are the fol lowing: 

o The pulp production in the Nordic countries 

has been increasingly integrated into paper production. This has been especially true for hardwood kraft pulp where new producers with substantially lower production costs have emerged on the 

markets. 

o The share of cultural papers where the 

share of fiber cost is less important have grown 

at the expense of industrial papers. 

o The Nordic producers have looked at new 

markets such as the Far East to take a share of 

the rapid growth of pulp and paper consumption. 

Increasing marketing efforts have a1 so been aimed 

at the USA which has been attractive due to the 

strong US do1 lar, 

o Fiber costs have been decreased as a result 

of new mechanical pulps developed in the Nordic 

countries such as the MP and PGW, 

o Consi.derab1 e investments in energy conservation have made the Nordic pulp and paper industry 

the most energy efficient in the world, 

o The new paper machines in the Nordic countries have been bigger than in competing regions 

resulting in lower manhours per ton of end product. 

o The Nordic pul p and paper industry has also 

experienced considerable restructuring which is 

still in progress. The result of this development 

is the bigger size of companies which enabf es more 

efficient units and greater rational ization of 

production. 

The pulp and paper industry in the Nordic 

countries today can be considered as a leader in 

the world with modern and cost efficfent production units. Its importance to the national economies will remain important for many years to come, 

but in order to keep its leading position on the 

key markets in Western Europe integration into 

papermaki ng shall be further increased and new 

paper products are developed where full advantage 

of the competitive advantages such as the low 

power rates and big production units can be taken, 

Pine Regeneration 

Moderator: 

Benton H. Box 

Clemson University 

SLASH PINE PLAEFPATION SPACING STUDY--AGE 30'' 

Earle P. Jones, Jr, 2 / 

Abstract.--In 

var. elliottii) 

5x10, 8x8, 6x12 

1952, slash pines (Pinus elliottii Eweln. 

were planted at spacings of 6x6, 6x8, 

, 10x10, 7.5~15, and 15x15 feet on an old 

field (site index 65 feet at age 25) in the middle Coastal 

Plain of Georgia, Except for a few trees rmoved to 

salvage ice damage, plots were not thinned, 1'4erchmtable 

volumes at ages 25 and 30 did not diff'er significantly 

among original spacings. Recomaendations are: (1) For 

pulpwoat production, plant 600-800 trees per acre and 

harvest at age 25. (2) For sawtimber, plant 600-700 trees 

per acre and thin at age 15 to 20, or plant 400 to 600 and 

delay thinniw until after age 20. 

INTRODUCTION 

Most studies of pine plantat ion spacings have 

incorporated some cultural treatment, such as 

fertilization or thinning, when the trees 

attained merchantable size. Although thinniass 

are certainly warranted in most pine plantations, 

it is interesting to see how slash pine (Pinus 

-- elllottii Engelm, var. elliottii) responds to 

eight spacings, unaltered by thinning or any 

other cultural activity. Early results of this 

study were reported after 8 years (Bennett 1960) 

and 12 years (Harms and Collins 196Q. Interim 

growth information derived from the study has 

been included in other reports (ennett 1963 and 

1975). Results through age 30 are reported here. 

METHODS 

The study site was an old field, which had 

been cultivated the previous year, on the Nolt 

Walton Experimental Forest in Dooly County, 

&orgia, in the middle Coastal Plain. The soil 

is loany sand, mostly of the Lakeland and Gilead 

series, In January 1952, nursery-run 1-0 slash 

pines from the Georgia Forestry Commission 

nursery at Albany, Georgia, were planted. The 

study was laid out in plots of approximately 

0.8-acre with a 12-foot wide firebreak around 

each plot. Two blocks were established, with 

each of the eight spacings represented in each 

block, Spacings were precisely measured in NS 

and El4 directions, and planting spots were narked 

with a peg prior to arrival of the seedling. 

Seedliws were dibble-planted under careful 

-- - 

- 1 / 

Paper presented at Fourth Biennial Southern? 

$$lvicultural Research Conference 

Atlanta, Georgia, liovember 4-6, 1986. 

- 2/ 

Research Forester, USDA Forest Service, 

Southeastern Forest Experiment Station, 

Macon, Georgia. 

supervision over a 24ay period when soil 

xoisture was plentiful. The Pew dead seedlinqs 

found in inspections were replacd in March and 

May of 1952, and resulting overall survival at 

the end of four growing seasons was 97 percent. 

Eight spacings were installed: 15x15, 7.5~15, 

18x10, 6x12, 8x8, 5x10, 6x8 and 6x6 feet 

(table 1 ). These spacings represent densities 

From 994 Lo 1210 trees per acre (TPA). Hardwoods 

and shrubs were never a probeen on this recently 

cultivated study site, and the few invading stems 

that did appear, including volunteer pines, were 

rernoved. 

Since age 12, zeasurenents have been taken on 

prmment hterior mea~ureaent plots of 

approximtely 0.37 acre. Measurements were made 

annually until age 22, then at ages 25, 28, and 

30. At these tires, d.b,h. was memured and 

crown class and mortality were noted of all trees 

on the sanple plot, Total. heights and live crown 

ratios were neasured on no less than 20 randomly 

selected trees proportionally representiq the 

1-inch diamter classes encountered. 

Dimeter distributions, height data, and plot 

dimension information were cssrtbined to generate 

stock and stand tables by I-inch diameter classes 

for total and rqerckantable cubic-%oat volu~ie, 

basal area, mean total heights of all trees and 

the dominant stand, and other stand paramters. 

For each treatment p!>t, by year, a 

keight4iamter relationship was fitted to the 

f orn : 

where: Log = comwn logarithm, base 10, 

W = total height (feet), 

D = diameter breat height 

(0,1 inch), and 

a and b = calculatd coefficients. 
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RESULTS 

Survival 

Initial planting densities ranged from 194 to 

1210 TPA (15x15 to 6x61, As would be expected, 

the number of surviving TPA remained directly 

related to initial density, through age 30, with 

but a few exceptions, Survival ranged from 91 to 

96 percent at age 10 (table 1). A severe ice 

storm on New Year" Dayy, 1964, at age 12, caused 

some top breakage and branch strippiw throughout 

the study. The 6x6 had significantly less damage 

than all other spacings. Those trees that 

appeared unlikely to survive were removed to 

reduce the risk of attack by bark beetles (Ips 

spp. and Dendroctonus spp. ), but reuovals as a 

percent of the number of surviving trees on the 

plots were not significantly different among 

spacings. By age 15, survival still was not 

significantly related to initial density and 

varied from 92 to 84 percent, Significant 

differences were apparent at age 20, in a range 

from 87 to 75 percent, Ry age 30, survival 

varied from 16 percent on the 15x15 spacing to 45 

percent for the 6x8 spacing, 

Most early mortality can be attributed to a 

combination of competition and fusiform rust 

caused by the fungus Cronartium quercuum (Berk.) 

Niyabe ex Shirai f, sp, fusiforne. Survival, at 

least through age 20, was above nornal for 

operational planting and represents very nearly 

the effect of full stocking at the initial 

spacing. 

Basal Area 

Total basal area has remained directly 

correlated with original spacing, with few 

exceptions, through age 25. By age 70 the three 

closest spacings (5x10 and closer) already had 

over 100 square feet of basal area per acre, and 

there was a 73-square-foot range between spacing 

extremes (table 1). By age 20, the four closest 

spacings (8x8 and closer) had converged at about 

150 square feet, and Prom age 20 to age 25, they 

showed little or no increase in basal area, 

Basal area stocking on all but the two widest 

spacings culminated at or before age 25, A 

maximum basal area of 165 square feet was reached 

on one of the 6x6 plots at age 25. Only the 

15x15 and 1,5x15 had not %horn a doamturn by age 

30 * 

Quadratic mean dianeters of all trees were 

calculated; they are perhaps 0.1 inch higher than 

the arithmetic mean. A siqnificmt difference in 

nean dimeter first eccurr& at age 5 at a 

density of 500 to 550 TPA (Bennett 4960), and 

mans have become increasiwly more divergent 

across the range of densities to age 30. Average 

diameter of all trees at the widest spacing was 

53 percent larger than that at the closest 

spacing at age 48, and 81 percent larger at age 

30 (table 1). The strong ef fect of planting 

density an d.b,h. can be seen in the fact that 

over the 1000-tree range of initial densities in 

this study, there are five or six significant 

differences in man dianreter. Two of these 

differences consistently occur at the two spacing 

extrmes--the 6x6 and 15x35 have simificantly 

smalier and larger diawters, respectively, than 

all other spaciws, At age 20, only the 15x15 

spacing had more than half its surviving trees in 

ner~h~table sizes, but by age 30 all surviviw 

trees were nerchantable at all spacings. 

Crown Ratio 

Crown ratio is important in maintaining 

diamter growth, and it Fs significantly related 

to stand density. Assuning a 35-pewent crown 

ratio is desirable in pulpkmad size slash pine, 

the 6x6 spacing was in Jeopardy at age 15, with 

32 percent of total height in green crown (table 

1 ). At age 20, all spacings 6x12 and closer 

(over 600 TPA) had less than 35 percent green 

erorm, and by age 25, only the 115x15 spacing 

still had 35 percent crown. 

Total Height 

Mean total height is usually not related to 

stand density among the densities normally 

encountered in managed stands of southern pines, 

This spacing study has been an exception since 

age 10 (Harm and Collins 1965, Lloyd and Jones 

1983). Plots planted closer than 8x8 (681 TPA) 

generally had significantly shorter trees through 

age 30 (table 1 ). Onby the very wide and very 

close spacims were clearly different in height, 

i,e,, fewer than 400 vs, more than 800 TPA. 

These height differences also have an effect 

on the estimation of site index when widely 

different densities are found on otherwise 

similar sides. The average height of the 

dominant stand at age 25 in this study is a 

direct measure of 25-year site index (table 11, 

and a 10-foot difference in site index can be 

recognized due to spacing, while the difference 

between blocks was not significant, With two 

overlapping significance ranges by Duncants test, 

the difference point can be generalized at 600 

TPA surviving at age 10, 

Perhaps we should rahd ourselves as we are 

looking for numbers to put into computer models, 

that site index was not originally intended as an 

absolute neasure of site potential, In fact, 

site index is usually estimatd to the nearest 

10-foot elass, In that light, variations of less 

than 10 feet are not serious defects, However, 

if these eight spacing treataents are assigned to 

10-foot site index classes, the three widest 

spacings will be site 10, and all others site 60. 

Merchantable Cubic-Foot Vollme 

From ages 10 through 30, there were very few 

significant differences in mrchant able volume 

production among the eight spcings, but 

variation among treatmnts was high (table 1). 

At age 10, the widest and closest spacings had 

significantly less vobuae than the intermediate 

spacings. At ages 15 and 20, only the 15x15 was 

significantly belgw other spacings in cubic 
volume. There was considerable variation in Averwe d.b*h. at spacings below 6x12 (less 

cubic volume among treatmnts at ages 20, 25, and than 600 TPA) were significantly larger than at 

30 (fig. l), but the differences at ages 25 and closer spacings, Aver%e dimetern of 10 inches 

30 were nqt statistically significant. were obtained by age 20 at the widest spacing 

( 200 TPAI , which is desirable for early sawtimber 

product ion. 

B 2 4 6 8 18 12 14 

TREES PER ACRE <X ID@> 

Figure 1 .--Merchantable volume over initial trees 

per acre and spacings, by age, for slash pine 

spacing study. 

These results should be viewed with caution. 

They represent only the effect of initial TPA 

(spacing) on volume, and not surviving TPA, which 

is the product of initial density and current 

survival percent. Yield studies consistently 

show a highly significant effect of surviving TPA 

on cubic volume yields (Bennett 1963). 

DISCUSSIOM AND COMCLUSZOMS 

Herchantable cubic-foot volunes at ages 25 and 

30 were not significantly different across the 

eight initial spacings in this study (15x15 to 

6x6, 194 to 1210 TPA), but yields for the two 

extreme spacings were consistently lower than for 

the others (table 1). However, spacing alone 

does not account for chmges in TPA over tine, as 

a result of mortality. Further investigations 

with these data will examine effects of TPA on 

growth and yield. 14ercbantable volune growth 

declined sharply after age 25 (fig. I), 

especially for spacings of 8x8 and closer (over 

680 TPA) . For example, the 6x8 spacing (900 TPA) 

had the highest volune of all spacings at ages 

15, 20, and 25, but fell to fifth highest at ase 

30, when the 7.5~15 spacing had the highest 

volune. Lacking significant differences in 

merchantable volume, the choice of initial 

spacing may therefore be based on other factors. 

Althowh this study was not designed to 

compare square vs. non-sqmre spacings, evidence 

indicates no significant difference in 

merchantable cubic voluae production through age 

30 due to spacing confi~ration. Ten feet or 

more between rows permits access into the stand, 

but apparently does not sacrifice merchantable 

volune production. 

Mutual competition was evident in the early 

decline of live crown ratio at the closer 

spacings. Crown ratio was approaching 30 percent 

by age 20 at spacings of 6x12 and closer (over 

600 TPA). If sawtimber is the objective, 

thinnings should be applied by age 20 for stands 

planted with over 600 TPA. Thinnings in stands 

starting from fewer than 600 TPA can be deferred 

until after age 20. Perhaps stands originating 

with 400 or fewer TPA could go unthinned to age 

30. Without thinning, basal area will peak at 

150-160 square feet per acre, and then declined 

due to mutual competition among planted trees. 

Several conclusions can be drawn from this 

study and applied to similar unthinned old-field 

slash pine plantations on sites 60 to 70: 

1. A 6x6 spacing is not efficient for 

merchantable volume production. 

2. Select a spacing pattern to allow 10 to 12 

feet be tween rows. 

3. For pulpwood production only, plant 600 to 

800 TPA and harvest at age 25. 

4. For sawtimber production, plant 600 to 700 

TPA and thin at age 15 to 20, or plant 400 to 600 

trees and delay thinning until after age 20. 

5. On similar sites, unthinned slash pine 

stands starting from 200 TPA will have dominant 

stand heights appsoximately 10 feet taller than 

plantings originatins with 1200 TPA. 

LITERATURE CITED 

Bennett, Frank A. Spacing and early growth of 

planted slash pine. Journal of Forestry 

58( 12) : 966-967; 1960, 

Bennett, Frank A. Growth and yield of slash pine 

plantations. Res. Pap. SE-1 Asheville, MC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Stat ion; 1963. 

23 P* 

Bennett, Frank A. Slash pine: some intriguiw 

~rowth and yield relationships. Res. Pap. 

SE-133. Asheville, tTC: U.S. Department of 

Agriculture, Forest Service, Southeast em 

Forest Experiment Station; 1975, 12 p. 
Bennett, F.A.; McGee, 6. £3.; Clutter, J.L. Yield 

of old-field slash pine plantations. Station 

Pap, No. 107. Asheville, NC: U,S, Department 

of Agriculture, Forest.Service, Southeastern 

Forest Experiment Station; 1959. 19 p. 

Hams, William R.; Collins, Arthur B., 111. 

Spacing and twelve-year growth of slash 

pine, Journal of Forestry 63(12) : 909-91 2; 

1965. 

Lloyd, F. Thomas, Jones, Earle P,, Jr. Density 

effects on height growth and its inrplications 

for site index prediction and growth 

projections. In: Jones, Earle P., Jr., ed. 

Proceedings of the Second Biennial Southern 

Silvicultural Research Conference; 7983 

November 4-5, 1982; Atlanta, GA. 

Gen, Tech. Rep. SE-24. Asheville, NC: U.S. 

Department of Agriculture, Forest Experimnt 

Station, 1983: 329-333. 
GOSVERTLKG "THE BABRENS" FROM LOW-QGALITY WDgOODS TO HIGH-YIELDING 

LOBLOLLY PIHE PL>NT~TT ION sL' 

2 :" 

Edward Buckaer, Richard Evans, John liullins and Eyvirad ThorAbstract,--A split-plot design was used to test no 

treatment, fire plowing and double disking as main treatments 

for controlling residual hardwoods following a comercial 

timber harvest and planting 1-0 seedlings vs direct seeding 

as sub-plot treatments for converting a low-quality hardwood 

stand to a loblolly pine plantation. This evaluation was 

made at plantation age 23. Double disking was nore effective than the other site preparation treatments and planting 

was more effective than direct seeding, annual 

growth where this combination was used was 2.4 cords per acre 

per year. Although less productive, the following treatment 

combinations resulted in stands of acceptable stocking: 

plow/plant, no site preparationlplant and disklseed. High 

yields from the diskedlplar'ted plots makes this treatment 

attractive for intensive management. Planting without site 

preparation appears to be a viable option on small ownerships 

where intensive site preparation is not feasible, 

1NTRCIS)UCTLON The "native" forests also suggest that these 

soils would be unproductive for forest crops, 

The long-term and high risk nature of forestry The dominant trees are ~rimarilv oaks - scarlet 

investment is such that production-oriented (Quercus coccinea L. ) , chestnut (Quercus prinus L. 1, 

foresters generally prefer to "practice their post (Quercus stellxta b?angenh,), blackjack 

trade" on suitable laxd that is free from conflict (Quercus -- marilandica Fuenchh.), and southern red 

with other possible land-use options (e.g,, 

wilderness, agriculeure, urban development, 

natural areas, etc,). Finding Land free from 

these constraints that is suitable for the practice 

of intensive forestry is becoming increasingly 

difficult as pressures for land increase. "The 

Barrens," an extensive region on the Eastern 

Eighland Rim in south-central Tennessee, may be oce 

such area. 

This flat to gently rolling region is covere6 

with a loess mantel in which soils develop that 

commonly have a fragipan at lC-2h inches. The 

characteristic soil for this region is Dickson 

silt loam (undulating phase), It is not in demand 

for agricultural crops although there is increasirg 

use for pasture. It is not suitable for subdivision 

development or other urban construction due to 

impermeability. Septic systems do not work 

efficiently, especially in the winter when a 

pearched water table commonly waterlogs the soils. 

i'Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, Xovember 

4-6, 1986, 

Zi~rof essor. Superintendent of Forestry 

Stations, Research Associate and Professor 

Emeritus, respectively, Departnent of Forestry, 

Wildlife 6 Fisheries, VnLversitp of 'Tennessee, 

Knoxville, TN 37901-1871. 

(Quercus falcata 2lichx.j with a few hickories, 

elms and an occasional ash. Understory trees are 

largely dogwood, soLtrwood and redbud. In the 

spring rapid evapotranspiration quickly dries the 

shallow rooting zone making drought a common 

occurrence during n'ucii of the growirig season, 

The pines native to Tennessee are not generally 

found in this region. 

A history of frequent fires, grazing and 

high-grading have combined to mask the potential 

productivity of these sites for forest crops. 

The general lack of interest in forest management 

by landowners likely results from the low inherent 

value of the native species, their degraded 

condition (fire scars, iimbiness, etc.) and a 

general lack of markets for unprocessed forest 

products. Converting these sites to pine has not 

been widely practiced as the region is outside 

the procurement zones for all but 2 or 3 pulp 

companies. 

In 1966 approximately 860 acres in 'The 

Barrens" was acquired 35 surplus povernment 

property by the University of Tennessee, essentially 

all of which supported a Low-quality hardwood 

forest that was typical for this region. 11: was 

composed of two distinct age classes - a poorly 

stocked overstory dozinated by oaks that were 

generally over 10-12 inches dbh and an understory 

of mixed hardwoods generally Less than 10 years 

old. In the mid-1350's an effective forest fire 

control program was impiexented in Tennessee which 

allotred tfie ;'our,ger zSe c_lass to become establis5cd. 
THE STUDY 

This study was established in the winter of 

1961-62. It was prompted by the apparent low 

productivity of the "nativefr forest cover. ,An 

early indica~ion of the greater productivity of 

loblolly pine on these soils was evident from 

plantations established on Arnold Engineering 

properties (a federal ownership) in the 1540's 

and 50's. 

Study objectives were to evaluate: 

I) mechanical site preparation aethods for 

controlling the residual hardwood understory sufficient to establish a loblolly 

pine plantation, 

2) planting vs seeding for establishing a 

loblolly pine plantation, and 

3) the potential for loblolly pine on these 

seemingly unproductive sites. 

METHODS 

All merchantable timber 12 inches dbh and 

larger on the 115 acre study area was removed in a 

commercial timber sale. The remaining o v e r s t o r y 

trees (3 inches dbh and larger) were injected 

using a mixture of 2,4-D and 2,4,5-T. There 

remained a hardwood understory that would compete 

with planted pines. 

The experimental design was a split plot 

arrangement of 3 site preparation treatments in 

which 2 planting methods were tested (Table I) . There were 3 replications; however, one was Largely 

destroyed by a wildfire in 1970. 

Table 1.--&ln and subplot treatments or the split 

plot experimental $@sip. 

Hain treatments were (plot size = 1,000' x 500') 

I. Control = no treatment of understory 

hardwoods (a few were dmagedfkilled by the 

logging operation). 

2. Fire plow = opening fire plow lanes on 8 

foot intervals. 

3. Double disking - uniform coverage of entxre 

area using bog-type disk. 

Sub-plot treatments were (~lat size 500' x 500'): 

1. Direct seeding of stratified loblolly pine 

seed. In the disked plats seeding was done 

with a cyclone seeder at the rate of one 

pound per acre. In the fire plow plots 

seeding was continuous along the bottom of 

the trench while in the eontrol plots 

seeded spots were spaced as were the 

planted trees and at the rate of 1/2 

pound per acre using a Panama seeder. 

2. Planting 1-0 loblolly pine seedlings on a 

spacing that would give 1,000 trees per 

acre (approximately 8' x 5.5'). 

These main and sub-plot treatment cornbinaclo~s 

give the following treatments in the 5.75 acre 

sub-plots: 

I. no site preparation + direct seedrng 

(in spots using Panma seeder) 

2. no site preparation + planting seedlings 

3. fire plow + direct seeding (conthuous 

along fire plow trench) 

4. fire plow + planting seedlings 

5. double disking + direct seeding 

(broadcast using Cyclone seeder) 

6. double disking + planting seedlings 

Site preparation and planting were done in 

the sprin~ of 2.962. Twenty five permanent sample 

plots were established in each treztment plot. 

The stand paraxeters used in this report were 

obtzined in the fall and winrer of 1984-85, 

follow in^ the 23rd growlrlg season. 

Nain treatment (site pseparationj effects 

indicate that double disking resulted in significantly greater stocking and basal areas than the 

other two treatments (Table 2). Plots receiving 

this treatment also had s2gnificantty greater 

tree heights than the control and greater cordwood 

volumes than the plowed plots. Plowing did not 

result in significant improvement ovel the controls 

for any of the measured parameters. These plots 

had the lowest stocking, which was likely due to 

competition from residual hardwoods and frost 

heaving (as planting was in the bottom of the 

furrow where water often stood during the winter 

months) . 

Table 2.--Stand density and growth parameters for 

the various treatment combinations. 

Trees DBH Height Basal Cords 

Treatment per Acre (in.) (feet) Area jsq.ft.) per Acre 

AVERAGES FOR. INDIVf DUAL TREATMENTS 

SITE PREPARATION 

None 351a 7.49 5sa 113.5~ 33. 5ab 

Plowed 304~ 8.00 57ab 106.6~ 32. 4a 

Disked 430b 7.76 5ab 146.6~ 45.1b 

PLANTING METHOD 

Seeded ~94~ 7.67 55a 97.1a ~8.6~ 

Planted 43~~ 7.80 5gb 149.6~ 46.0~ 

AVERAGED FOR COMBIhTD TEAT~NTS~' 

afValues in columns followed by the same letter are not 

significantly different at the .05 probability level 

according to Duncan's Plultiple Range Test. 

Il-lStatistical analysis of the combined treatments was not 

appropriate due to a fire that destroyed portions of 

two replications. 

All of the tree/stand parameters measured 

were higher in the planted plots than in those 

established by direct seeding (Table 2). The 

one-year growth advzntage of planted seedlings 

Likely xade them bct ter competitors against 

hardwoods and acc3unts for their Larger size. 

Higher stocking in a71 plsnted plots was not the 

case at age 5 when the C'oubLe disked/direct seeded 

plots had 2,471 trees per acre, the heavest 

stocking in the study at that Lime (Thor arid 

Huf fman, 1969). Ifiile high mortality is expected 

with stand developrrient in such overstccked stands, 

a contributing factor may have been the slow 

early growth of seeded pines relative to sprouting 

hardwoods. 

Although not analyzed statistically, all of 

the t ree/stand parameters measured nxcept average 
diameter were the highest in the diskedlplanted 

plots (Table 2). This indicates rhar the rapid 

development of fully stocked pine s~ands is 

strongly dependent on effectrve control cf hardwoods and the growth advantage providcc by ;-0 

pine seedlings. \Chile the kiigk stand de~sities 

likely reduced diameter growth, only the plow/'seeded 

plots had higher average diazettrs. These large 

diameters were likely due to the low stocking 

conb ined wit some hardwood control. However, 

stocking in th~se plots was unsat isf actor?. 

All stand parameters were the lowest where 

direct seeding was done with no site preparation 

(Table 2). Nct only were these plots understockeb, 

but individual tree parameEers (height/aiameter) 

were the lowesc. This likely reflects the growth 

advantage of the relatively undisturbed hardwoed 

understory over the direct seeded pines resulting 

in slow pine growth and high mortality, 

Stands with satisfactory stocking were obtained in all of the planted plots and in the 

direct seeded plot that was double disked. In 

planted plots tree height and diameter appeared 

to improve with increasing intensity of site 

preparation but did not appear to be related to 

pine stand density. This suggests that the growth 

of individual pines, although in "free-to-grow" 

positions, were strongly influenced by the residual 

hardwoods. Low stocking in the plowlplant plots 

resulted because frost heaving was especially 

damaging to pines planted in the plow furrow, 

Idhile this resulted in the Lowest basal areas 

and volumes in the planted plats, these stands are 

now fully stocked able 2) . 

For both planting methods average diameter 

and height were the lowest whtre there was no 

site preparation. Since these parameters did not 

appear to be influenced by pine stocking the 

slower growth is likely due to hardwood coinpetition, 

which was especially appare~t in the seeded plots. 

Since height differences ar~ong treatments 

were small and even the smaller pine s were of 

pulpwood size, there was a strong correlation 

between basal area and cubic volume (cards) per 

acre (Table 2). Considering direct seeding with 

no site preparation to he the nlnimum si;viculture 

that might be applied in establishing pines on 

these sites after removal of the hardwood ovcrstory, cubic volume gains achieved in th%s study 

from applying more intensive treatrents sere: 

no site prep (plowed < disk& ' plowed < no site prep, disked 

seeded seeded seeded planted planted planted ----___-_----__--_---------------------------------------------- 

established on a "regular" spacing, as is best 

accomplished by planting genetically improved 

stock suited to the planting site, greatly increasts 

the likelihood of obtaining vigorous, fully-stocked 

plantations in which competing hardwoods do not 

seriously erode productivity. 

A major finding in this study was the productivity of the loblolly pine plantations established 

on these seemingly unproductive sites (Figure 1) . 

MEAN ANNUAL GROWTH OF LOBLOLLY PINE 

N GORDS PER ACE PER YEAR 

r--7 

SEEDED 

Figure I. Average annual growth in cords per acre 

per year for 23 year old loblolly pine according 

to site preparation and planting methods. 

Average annual growth of 2.4 cords/acre/year on a 

23 year rotation represents high productivity even 

for the better pine sites in the South (Smalley 

and Bailey, 1974). That this occurred on "The 

Barrens" where pines do not normally grow and 

native hardwoods are largely inferior species of 

low quality, suggests that a significant improvement in forest productivity can be achieved by 

applying intensive forest practices that are now 

"standard" throughout much of the South. Although 

planting following commercial logging an6 inj ection of ovzrstory trees without further site 

preparation established an acceptable plantation 

in this study, it is questionable whether this 

would be successful under present conditions. A 

long period of effective fire protection has 

resulted in larger, more vigorous hardwood stands. 

A similar treatment today would not likely be as 

effective as was the case in this study. 

Additional research needed to further define 

the potential for pine on these sites includes 

studies on: 1) forest fertilization, 2) ripping 

(to fracture the fragipan), and 3) carrying the 

pine through a sawtimber rotation. A study to 

test thinning and prescribed burning as suitable 

treatments for maintaining stand vigor through a 

sawtimber rotation is being implemented on this 

study site. 

LITEk4TURE CITED 

The significant gains tchie-ced in this study 

through intensive site preparatian and planting 

seedlings are consistent with experience in pine 

plan tat ion management throughout the Sot~rt. 

Controlling the aggressive hardwoods tbtt compete 

with and constantly threaten to r~place ylne: on 

essentially all sites in the South is essential if 

vigorous, fully-s tockeb pine plantations are to 'he 

maintained. The rapid early growth of pines 

Thor, E. and P. J. Nuffman. 1949. Direct seeding 

and planting of loblolly pine on the Highland 

Rim in Tennessee. Tree Planters Kotes Vo. 20(2). 

p. 19-22. 

Smalley, G. W. and R. L. Bailey. 1974. Yield 

tables and stand structure for loblolly pine 

plan tat ions in Tennessee, Alabama and Georgia 

Highlands. UCDii-For. Ser. Res. Pap. SO-96. Slp. 
RELATIONSHIPS BETWEEN HEIGHT GROWTH AND ROOT SYSTEM ORIENTATION 

I /

IN PLANTED AND SEEDED LOBLOLLY AND SHORTLEAF PINES 

4/ Constance A. Harrington2', William C. Carlson2/, and John C. BrissetteAbstract.--Trees in 34 young (3 to 8 year-old) loblolly (pinus 

- taeda L.) and shortleaf pine (pinus echinata $fill.) stands in 

Arkansas, Oklahoma, and Texas were sampled to characterize the 

general root system orientation of planted and seeded trees. 

Seventeen stands had been planted, and 17 had been regenerated via 

artificial or natural seeding, In each stand, 12 trees werg 

excavated and total height and height growth increments for the 

previous 3 years were recorded. Stand origin, either planted or 

seeded, influenced the percentage of trees in each of four general 

root system orientation classes. For both species, seeded trees 

were much more likely to have a single taproot type of root system 

than planted trees. For seeded and planted trees of both species, 

trees with root systems oriented downward (either with a main 

taproot or with several lateral roots) had better height growth than 

trees with surface-oriented root systems. The least favorable root 

orientation class differed by species; surface-oriented lateral 

root systems were least favorable for shortleaf pine, and taproots 

not oriented downward were least favorable for loblolly pine. 

Overall, 3-year height growth did not differ between seeded and 

planted trees; however, planting did increase the percentage of 

trees in the root orientation classes which were less favorable for 

height growth. 

INTRODUCTION 

Loblolly (pinus taeda L.) and shortleaf (P, 

echinata Elill.) pine are the major commercial 

tree species in Arkansas, southeastern Oklahoma 

and northeastern Texas. The natural range of 

shortleaf pine extends farther west and north 

than that of loblolly pine o ow ells 1965); 

however, in central Arkansas and southeastern 

Oklahoma large-scale plantings of loblolly pine 

outside of its natural range have been very 

successful (~ambeth and others 1984). In many 

- 1 / 

Paper presented at Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

- */ Research forester, Southern Forest 

Experiment Station, USDA Forest Service, 

Monticello, AR 71655, in cooperation with the 

Department of Forest Resources and Arkansas 

Agricultural Experiment Station, University of 

Arkansas at Monticello. 

- 3/ 

Tree physiologist, Weyerhaeuser Company, 

Southern Forestry Research Center, Hot Springs, 

AR 71902. 

- 41 Research forester, Southern Forest 

Experiment Station, USDA Forest Service, 

Pineville, LA 71360. 

areas, when natural stands of shortleaf pine are 

harvested, the site is regenerated by planting 

loblolly pine because of the greater growth 

rates that can be achieved over short rotations 

by loblolly on some sites. 

In addition to inherent differences in 

growth rates between loblolly and shortleaf 

pines, other reasons for differential performance 

in plantations include differences in the quality 

of planting stock produced by nurseries and 

differences in the way the root systems of each 

species develop after planting. This study was 

designed to investigate if: (1) there were species 

differences in root system orientation between 

planted and seeded trees, and (2) differences in 

root system orientation were associated with 

differences in height growth, The information 

presented here is part of a larger study 

comparing root systems of planted and seeded 

loblolly and shortleaf pines. 

METHODS 

Seventeen paired plots (34 plots in total) 

were set up in 3- to 8-year-old, well-established 

stands of either loblolly er shortleaf pine in 

Arkansas, Oklahoma, and Texas (fig. 1). One plot 

of each pair had been regenerated by artificial 

or natural seeding; the other had been planted 

using a local seed source. Both plots of each 
Figure 1. Location of sites used in root 

system orientation study: X= loblolly pine 

site, 0= shortleaf pine site. 

plot pair were of the same tree species, on 

similar soil with comparable site conditions and 

located within I0 km of each other; mean ages 

differed by a maximum of 2 years. Plots were 

established in both the Interior Highland and 

Upper Coastal Plain physiographic provinces. As 

would be expected given the overall range in site 

conditions and tree age, mean tree size varied 

substantially (table 1). 

Randomly generated X-Y coordinates were used 

to locate 12 sampling points in each plot; the 

tallest of the five trees closest to the sampling 

point was chosen as a sample tree if it appeared 

healthy, free from major damage, and had one main 

terminal leader. If the tallest tree did not 

meet the criteria, another tree was substituted, 

Trees with minimal top damage were selected; 

however, on some sites almost all trees exhibited 

repeated replacement of the main terminal. The 

observed damage was probably caused by Nantucket 

pine tip moth (~hyaeionia frustrana). 

Each sample tree was tagged on the north 

side and marked to indicate location of the 

groundline. Trees were then excavated using 

shovels and mattocks to a depth of approximately 

40 cm. Lateral roots were severed about 20 cm 

out from the base of the tree. Total height and 

height increment for the three growing seasons 

prior to excavation were measured for each tree, 

Height increments were determined by counting the 

number of height growth flushes and using 

characteristics such as relative needle length, 

relative flush length, needle retention, and 

changes in bark and branching characteristics. 

Questionable flushes were assigned to the correct 

year by cutting above and below the bud scale 

scars and counting the number of annual rings, 

After the height measurements were taken the tops 

of the trees were severed from the roots 15 to 25 

cm above the groundline mark, 

Root systems were transported to the 

laboratory, washed, and then either measured 

immediately or stored indoors until measured, 

Prior to measurement, stored root systems were 

rehydrated by soaking in water for 24 to 48 

hours. Roots were suspended in a cylindrical 

frame for measuring; the groundline mark was 

placed at the top of the frame. The frame was 36 

cm deep and divided into three 12-cm deep layers. 

Each layer was subdivided into 4 compass 

quadrants; thus, the frame had 12 measurement 

sections plus a top and a bottom. Tree diameter 

was measured at the groundline mark. 

Root systems were classified as to their 

general orientation (fig. 2). Orientation 1 was a 

root system with one majar root oriented 

downward. No attempt was made to distinguish 

between undisturbed taproots and a major root 

that may have originated after the original root 

was cut or damaged. Orientation 1 also included 

taproots with major turns if the overall 

orientation of the root system was primarily 

downward; thus this category would have included 

both trees with sLraight (vertical) taproots and 

trees with a taproot originally in a "L" or llJ" 

configuration that recovered or corrected itself 

and grew downward. Orientation 2 was for root 

systems having one major root, but the root 

system was not oriented downward; this included 

root systems having an "L1' or "JW configuration 

that were not included in orientation 1. 

Orientation 3 was applied to root systems that 

had a downward orientation but more than one 

major root was involved. This included root 

systems with two to four large "sinker" roots as 

well as more fibrous root systems with a strong 

downward orientation. Orientation 4 was for root 

systems without a major root where the 

orientation of the lateral roots was primarily 

outward rather than downward. 

The number of major turns made by the 

taproot between groundline and where the taproot 

ended or where it exited the measuring frame was 

recorded for all roots. After the root systems 

were measured the stump was severed from the root 

system at the groundline mark and aged by 

counting the number of annual rings. 

Planted and seeded trees were compared by 

root orientation class using a chi-square test 

for each species-physiographic province 
Table I .--Mean tree characteristics by species, physiographic province and stand origin. 

Total height 

Shortleaf pine Interior Highlands Seeded 5 4*4 I/ 1.5 3.5 

(0.4)- (0.3) (0*6) 

Planted 5 4.1 3 -4 3.5 

Coastal Plain Seeded 4 6.5 4.2 8.3 

(1 .o) (1 *o) (1 

Planted 4 5 -7 3.8 8 * 3 

Loblolly pine Interior Highlands Seeded 4 4.8 2*1 5.8 

(0 4 ) (0.1 

Planted 4 5.3 2.2 6.2 

Coastal Plain Seeded 4 7-1 5.3 10.0 

(1.1) (1 *I ) (1 *7) 

Planted 4 6. I 4 - 3 10.3 

't / 

- Yalue in parentheses is the mean absolute difference between seeded and planted paired plots. 
group, Differences between planted and seeded 

trees in annual and 3-year total height growth 

were tested on a paired-plot basis and by 

combining trees in each species-physiographic 

province group, The effects of root orientation 

class on height growth were examined by: (1) 

comparing weighted averages for height growth by 

root class for each species-province combination, 

and (2) ranking root orientation classes in each 

plot by height growth in the year preceding 

excavation. A split-plot analysis of variance was 

precluded by the number of empty cells. Loblolly 

and shortleaf pine plots had not been paired in 

site selection. Thus statistical tests of the 

differences between species were not appropriate 

and direct comparisons between species could not 

be made. 

RESULTS AND DISCUSSION 

Root orientations 

The majority of seeded loblolly and shortleaf 

pines had a taproot type of root system (root 

orientation class 1; table 2). There were small 

but consistent differences between provinces and 

between species in the percentage of seeded trees 

having taproots; these differences could be the 

result of variability in plant populations or 

could be related to the generally higher rock and 

gravel content in the Interior Highlands compared 

to the Coastal Plain. In addition, shortleaf pine 

plots in the Interior Highlands had higher rock 

contents than the loblolly pine plots. For both 

species in both provinces, the distribution of 

root systems by root orientation class differed 

between planted and seeded trees. The percentage 

of trees in orientation I was Lower in planted 

than in seeded stands, and, in general, the 

percentage of trees in the other three root 

classes was higher in planted stands. 

Planted trees of both species were more 

likely to have one major root (orientation 

classes 1 and 2) in the Coastal Plain than in the 

Interior Highlands. The reasons for this 

difference between physiographic provinces are 

not known. Growing conditions on the Coastal 

Plain sites were generally more favorable and 

this may have encouraged the retention of a 

taproot type of root structure. Root systems 

with two or more major laterals heading downward 

(classified as orientation class 3) could have 

"grown into" orienta"con class 1 if one of the 

downward-oriented laterals increased in relative 

size and appeared dominant or if two or more 

roots twisted together, were overgrown, and 

appeared as one root. This type of scenario is 

more likely to have occurred in the Coastal Plain 

than in the Interior Highlands because the root 

systems in the Coastal Plain were more developed 

due to their somewhat greater age and better 

growing conditions, 

Height growth 

As would be expected in these young stands, 

annual height growth is still increasing over time 

(table 3). Differences in 3-year and annual 

height growth between planted and seeded trees 

were generally small and inconsistent. None of 

the paired-plot analyses of the total 3-year 

height growth resulted in statistically 

significant (p=0.10) differences between planted 

and seeded trees for either loblolly or shortleaf 

pine. Analysis of height growth by the three 

individual years also resulted in nonsignificant 

differences between planted and seeded plots for 

shortleaf pine in both provinces. 

The seeded loblolly pine plots in the Coastal 

Plain had significantly greater annual height 

growth the 3rd year prior to excavation (n-3) than 

planted trees; however, this difference in growth 

between stand origins was not maintained over 

time. 

The loblolly pine plots in the Interior 

Highlands exhibited a different pattern of height 

growth for seeded and planted stand origin types. 

For these plots, seeded stands had significantly 

less annual growth than planted stands the 3rd 

year prior to excavation (n-3), the same growth 

the 2nd year prior to excavation (n-2), and 

greater annual growth the year prior to excavation 

(I) This group of loblolly P"ine plots was more 

similar in stand history than the other speciesprovince groups, and this greater similarity may 

have allowed small differences in height growth 

patterns to be visible. All the loblolly pine 

plots in the Interior Highlands had been either 

planted or seeded after the regeneration failure 

associated with a severe drought in 1980, Thus, 

although the stands had been established the same 

year, the seeded stands were a year younger (age 

from seed) than the planted stands, and initially 

had poorer growth. Once the seeded trees became 

well established, however, they were able to 

catch-up to the planted trees, The fact that the 

seeded trees were able to catch-up with the 

planted trees indicates that there may have been 

detrimental effects associated with the plantings. 

Helght growth by root orientation class 

The patterns of height growth by root 

orientation class differed between species but 

were generally similar for planted and seeded 

trees and across provinces (table 4). For both 

planted and seeded shortleaf pine in the Interior 

Highlands, orientation class 4 had the poorest 

mean height growth; there was very little 

difference in mean growth between the other three 

root classes. Planted shortleaf pine in the 

Coastal Plain followed the same pattern--with the 

poorest mean height growth associated with 

orientation class 4. Seeded shortleaf pine in 

the Coastal Plain exhibited a different pattern, 

with the best growth in orientation root class 4 

and the worst in orientation class 2. This 

anomaly was based on a few trees, however, and is 

probably the result of sampling variability. 
Table 2.0- tribution of root systems by root orientation class, stand origin, physiographic province and 4Y species, - 

Number(and percent) of root systems 

by root orientation class 

Physiographic Stand x P 

Species province origin 1 2 7 4 level 

Shortleaf pine Interior Highlands Seeded 38 ( 63 ) 2( 3) 13 ( 22 7 ( 12 ) 

9.81 0.025 

Planted 21(35) 5(8) 22(37) 12(20) 

Coastal Plain Seeded 35(73) 2(4) 7(15) 4 (8) . 6.15 0.150 

Planted 25(52) 8(17) 8(17) 7(15) 

All Plots Seeded 73(68) 4(4) 20(18) lj(10) 

15.02 0.005 

Planted 46(43) 13(12) 30(28) 19(18) 

bblolly pine Interior Highlands Seeded 37 (TI ) 3( 6) 5(10) 3 (6) 

24.22 0.005 

Planted 14(29) 3(6) 23(48) 8(17) 

Coastal Plain Seeded 39(81) l(2) 6(12) 2(4) 

14.02 0.005 

Planted 22(46) 7(15) 12(25) 7(15) 

All Plots Seeded 76(79) 4(4) Il(12) 5 (5) 

34.38 0.005 

Planted 36(38) 10(10) 35(36) 15(16) 

The hypothesis that planted and seeded trees did not differ in their distribution across root orientation 

classes was tested using chi-square ( x2), 

Table 3---Mean height growth by year prior to excavation, stand origin, physiographic province and 

species. 

Species Physiographic Stand 

1 / Mean height growth by yearprovince origin n-3 n-2 n-I 3-yr total ---------cm----------- - 

Shortleaf pine Interior Highlands Seeded 3 1 42 52 125 

Planted 28 42 62 132 

Coastal Plain Seeded 76 76 100 252 

Planted 71 83 106 260 

Loblolly pine Interior Highlands Seeded 40** " 58 88** I86 

Planted 48 56 76 181 

Coastal Plain Seeded 92w 92 115 299 

Planted 80 98 121 299 

- I/ n-3 = 3 years prior to excavation, n-2 = 2 years ... Significance of differences in growth between planted and seeded trees in a species-physiographic 

province group is indicated by the symbol next to value for seeded trees, *p<0.01. 
Table 4,--Eean height growth the year prior to excavation by root orientation class, stand origin, 

physiographic province, and species. 

Species Physiographic Stand 

1 l Height growth by root orientation class- ----------cm---------- - province origin 1 2 3 4 All classes 

Shortleaf pine Interior Highlands Seeded 53 52 53 43 52 

Planted 66 68 64 47 62 

Coastal Plain Seeded 95 90 119 122 100 

Planted 109 98 118 91 105 

Loblolly pine Interior Highlands Seeded 90 66 88 86 88 

Planted 70 58 83 76 76 

Coastal Plain Seeded 174 89 136 I00 115 

Planted 127 103 124 114 121 

Refer to Table 2 for the number of roots in each class. 

Table 4 combines information from trees in 

each species-province combination; differences 

between values on each line of the table could be 

due to plot effects as well as the effects of 

root orientation class. The plot effects were 

eliminated by examining the effects of root 

system orientation on height growth on a plot-byplot basis. For each plot the root orientation 

class having the best height growth was 

determined (table 5). For shortleaf pine, 

downward-oriented classes (orientation 1 and 3) 

had the greatest number of plots with the best 

height growth. Orientation class 4 did not have 

the best height growth in any of the shortleaf 

pine plots sampled. Loblolly pine exhibited a 

similar pattern with the downward-oriented 

classes (1 and 3) most frequently having the best 

height growth per plot. Orientation class 2 was 

apparently the least favorable class for loblolly 

pine, as no plots were tallied in this class. 

GENERAL DISCUSSION AND CONCLUSIONS 

Root system structure or general orientation 

can affect tree performance in several 

categories: initial survival, initial and later 

growth, stability (e.g., resistance to windthrow 

or snow and ice damage), and response to 

silvicultural treatments (e.g., soil-active 

herbicides). Our study was based on healthy 

trees in well-established stands. Thus nothing 

can be concluded about the effects of root 

orientation on survival or stability. 

Loblolly pine, on the other hand, had the 

poorest height growth in orientation class 2; 

this pattern was consistent for planted and 

seeded trees in both provinces (table 4). In 

general, loblolly pines in orientation class 1 

had mean height growth approximately equal to or 

better than the average for all orientation 

classes. Planted loblolly in the Interior 

Highlands were an exception. Examination of the 

data on the number of major turns made by the 

tap or main root revealed a possible reason for 

this discrepancy. If loblolly pine seedlings 

are sensitive to root deformation as may be 

indicated by the poorer growth associated with 

orientation class 2, then poorer growth should 

also be associated with trees in orientation 

class 1 that had major turns. Planted loblolly 

pines in orientation class 1 in the Interior 

Highlands had an average of 2.7 major turns per 

tree, while seeded trees averaged less then 0.5 

turns per tree, No major turns were recorded 

for either planted or seeded loblolly pine in 

orientation class 1 in the Coastal Plain. 

Coastal Plain trees may have had fewer turns 

recorded because the sampled soils had fewer 

restrictions to rooting (and would have been 

easier to plant in). In addition, the root 

systems of young trees are very plastic and can 

quickly grow over bends or twists that do not 

result in large displacements from the center of 

the main root. Thus the generally older and 

larger trees on the Coastal Plain have put on a 

thicker sheath of wood than those in the 

Interior Highlands and may have tfhiddentt or 

grown over any major turns that were associated 

with stand establishment. 
Table 5.--Distribution of the maximum mean height growth per plot sh ax W) the year 

prior to excavation by root orientation class, 

- 

Physiographic Stand 1 / Max W by root classSpecies province or~gin 1 2 3 4 

- - - number of plots - - - - 

Shortleaf pine 

Total all plots 

Loblolly pine 

Total all plots 

Interior Highlands Seeded 

Planted 

Coastal Plain Seeded 

Planted 

Interior Highlands Seeded 

Planted 

Seeded 

Planted 

Coastal Plain 

'I Root orientation classes with only one value per plot were excluded from consideration 

All root systems in this plot classified as root orientation class 1. 

Differences were observed between seeded and 

planted populations in the percentage of trees in 

the four root system orientation classes, In 

particular, planted trees were much less likely 

to have one main downward oriented taproot than 

seeded trees. When all trees were combined, 

there were no significant differences in 3-year 

height growth between planted and seeded trees. 

However, there were some differences in height 

growth between root orientation classes, and 

planting increased the percentage of the 

population in the less desirable root orientation 

classes. Height growth was best in the root 

classes with downward-oriented root systems. The 

effect of root deformation or root orientation in 

relation to height growth differed somewhat by 

species. In particular, loblolly pines performed 

poorest in root orientation class 2, and shortleaf 

pines performed poorest in root orientation class 

4 

The results of previously published studies 

on the effects of root orientation or deformation 

on future growth have not been consistent. Hay 

and Woods (1974) reported that larger loblolly 

pines had more root deformation than smaller 

seedlings and speculated that root deformation 

may stimulate growth, They also commmented that 

the larger seedlings (with more root deformation) 

had more surface roots, which may initially be 

beneficial in taking advantage of summer showers. 

Hay and Woods (1974) mentioned the possibility 

that the largest seedlings at the time of 

planting may have been more likely to have 

been J-rooted than smaller seedlings. This 

alternative hypothesis was confirmed by field 

studies reported by Mexal (and others) 1978. 

Therefore it seems quite possible that the largest 

seedlings initially grew the best, in spite of 

root deformation. 

In another study, loblolly pine seedlings 

were planted with purposely deformed roots 

(~abrera and Woods 1975). They reported no 

statistical differences in height between 

treatments at age 3. It is noteworthy, however, 

that photographs of root system structure showed 

less variation than encountered in the present 

study, and that the ranking of growth by 

treatment showed better growth in the treatments 

with the least deformation, Another reason for 

the differences in results between the Cabrera 

and Woods study in 1975 and this study is the 

definition of the root orientation (or 

deformation classes), We compared height growth 

based on root system orientation at the end of 

the height-growth period, while they used root 

system characteristics at the time of planting. 
For example, our root orientation class 2 

included only root systems with uncorrected J or 

L configurations, while their roots with J or L 

configurations could include both root systems 

that remained as J or L and root systems that 

corrected themselves. 

Root system deformation and general root 

system orientation are factors in the long-term 

performance of both loblolly and shortleaf pine 

plantations, Foresters should maintain tight 

controls over the quality of the planting to 

ensure that expected growth rates are achieved. 

Careful writing of planting contracts with 

penalties for nonperformance and on-the-job 

inspections should result in more uniform and 

better growing plantations. In addition, 

utilization of site preparation treatments such 

as ripping, which make it easier to correctly 

plant trees, should also result in less root 

system deformation and better seedling 

performance. 

ACKNOWLEDGEMENTS 

We thank personnel from the Ouachita and 

Sabine National Forests and John Troth, 

Weyerhaeuser Co. for locating potential study 

sites. 

LITERATURE CITED 

Cabrera, Komero; Woods, Frank W. Effects of root 

deformation upon early growth of lsblolly 

pine (pinus taeda L.). Tennessee Farm and Home 

Science Progress Report 93. Knoxville, TN: 

University of Tennessee; 1975: 28-30. 

Fowells, H. A. compiler. 1965. Silvics of forest 

trees of the United States, Agric. Handb. 

271. U.S. Department of Agriculture, 

Washington, DC, 761 p. 

Hay, Ronald L.; Woods, Frank W. Root deformation 

correlated with sapling size for loblolly pine. 

Journal of Forestry. 72(3) : 143-1 45; 1974. 

Lambeth, LC.; Dougherty, P.M.; Gladstone, W.T.; 

McCullough, ROB.; Wells, 0.0. Large-scale 

planting of North Carolina loblolly pine in 

Arkansas and Oklahoma: A case of gain versus 

risk. Journal of Forestry. 82(12): 736-741; 

1984. 

Mexal, John; Burton, Sally. Root development of 

planted loblolly pine seedlings. In: Van 

Eerden, Evert; Kinghorn, James M., eds. 

Proceedings of the Root Form of Planted Trees 

Symposium. British Columbia Ministry of 

Forests/Canadian Forestry Service Report No. 8. 

Victoria, BC: Province of British Columbia, 

Ministry of Forests; 1978: 85-89. 
NURSERY CULTURAL PRACTICFS, SEEDLISG MORPHOLOGY, XSD 

FIELD PERFORMAKCE OF LONGLEAF PIKE" 

Glyndon E. EIatchellZ 

Abstract.--Preliminary results of a nursery and 

outplanting study of longleaf pine indicate that nursery cultural practices and certain morphological 

attributes of 1-0 bare-root seedlings strongly affected 

early field performance on a sandhills site. Seedbed 

density and lateral-root pruning altered morphological 

attributes of stock. Lateral-root pruaing, which was 

associated with increased abundance of fibrous routs 

and ectomycorrhizae, significantly improved survival 

during droughty conditions in the spring and summer of' 

the first growing season. Seedling vigor and survival 

were strongly correlated with abundance of fibrous 

roots and ectomycorrhizae, the number of large firstorder Lateral roots, and the interaction of these 

attributes. 

INTRODUCTION 

Morphological and physiological characteristics of planting stock and genetic factors 

influence the quality of southern pine seedlings 

(Brissette 1984). The ultimate measure of seedling quality is generally considered to he field 

performance. 

Results of nursery and outplanting studies of 

longleaf pine (Pinus 2aZustric Mill.) indicate 

that inoculation of fumigated nursery soil with 

PisoZithus tinctorius (Ptj during spring sowing 

and certain nursery cultural practices greatly 

increase survival and early growth of seedlings 

planted on deep sandy soils (Hatchell 1985). In 

addition to inoculation, nursery cultural practices 

that increase development of fibrous roots, such 

as optimum seedbed density, Lateral-root pruning, 

maintenance of optimum nutrient availability, and 

adequate growing space between individual seedlings, 

also tend to increase seedling quality. This research showed that seedlings with abundant fibrous 

roots and abundant ectomycorrhizae survived and 

grew better than seedlings with smaller and fewer 

fibrous roots supporting few ectomycorrhizae. 

This paper summarizes preliminary results of 

a longleaf pine study testing seedling responses 

in the nursery and in the field. The objectives 

of this study were (1) to fest the effects of 

nursery cultural practices on morphological 

attributes of bare-root seedlings and on field 

performance after outplanting on a sandhills site, 

and (2) to associate key morphological attributes 

of the seedlings with field performance for a 

'paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2~esearch Forester , Southeas tern Forest 

Experiment Station, U.S. Department of Agriculture, 

Forest Service, Athens, GA 30602. 

better understanding of seedling quality and for 

possible use as a guide for culling poor quality 

seedlings. 

NURSERY EXPERIMENT 

Seedling produeti%.--Seedlings were produced 

in 1985 at the Whitehall Experimental Nursery, 

Athens, Georgia. Aboveground nursery beds containing a uniform mixture of Forest topsoil, sand, 

and milled pine bark (2:1:1, volume ratio) were 

fumigated with methyl bromide under clear plastic. 

Soil samples collected after fumigation were 

analyzed and, in ppm, the average nutrient contents of the soil were: total N = 460, available 

P = 38, and extractable K, Ca, and Mg = 74, 220, 

and 19, respectively; pH was 4.7 and organic matter 

content was 1.2% (Analyses by A&L Laboratories, 

Inc., Memphis, Tennessee). These relatively high 

nutrient contents were from residual fertilizer 

concentrations applied in production of longleaf 

pine in previous years. Fertilizer (10-10-10) was 

broadcast at 500 lb/acre. Vegetative Inoculurn of 

Pt, with a moisture content of 72 percent and pH 

5.11 was mixed with the upper 4 inches of soil 

before sowing at the rate of 75 ml jft2 of soil 

surface. Longleaf pine seed (Dodge County, 

Georgia, seed source) were sown on March 20, 1965, 

at two times the desired seedbed density, and 

nursery beds were thinned Play 20, 1965, to the 

seedling density that was assigned to each plot. 

The nursery phase of this study was a 2x2~2 

factorial experiment replicated in four randomized 

complete blocks. The factors and Levels consisted 

of two seedbed densities (5 or 12 seedlings/ft2), 

two spacings of seed drills (6 or 12 inches), and 

two lateral-root pruning treatments (pruned or un-, 

pruned). Offset "double" drills were sown at the 

12-inch spacing to provide additional growing space 

between seedlings. Lateral roots were pruned on 

June 25, August 16, and September 30, 1985, by 

vertically cutting roots midway between seed 

drills to a depth of 6 inches. 
seedlings were side dressed on June 24, July 

15, g gust 13, and September 3, 1985, with ammonium 

nitrate at the rate of 50 lb/acre X and with muriate 

of at the rate of 10 lb/acre K. Captan was 

applied as a drench to the soil in all beds at 4.2 

lb/acre on Xarch 26, 1985. Benlate was applied as 

a drench at the recommended rate from .July to 

October to controi P~~zs(::G~:-+cI needle blight. 

~ifcing and evaluating stock.--Seedlings were 

lifted and seven morphological attributes of each 

seedling were assessed on December 9 to 12, 1985. 

A11 seedlings from the border rows of all plots 

were excluded from this assessment. Fifty healthy 

and undamaged seedlings with >3/16 inch root-collar 

diameter (RCD) and having other specifications of 

plantable stock suggested by Wakeley (1954) were 

randomly selected from each of the 32 plots in the 

nursery experiment for outplanting. 

Seedlings that did not meet specifications of 

I.j'akeleyfs (1954) grade 1 or 2, had mechanical 

damage or had fusiform rust (Cronizr t i>*ri yueuacu;lm 

(Berk. ) Miyabe ex Shirai f . sp. I~~~i*~m) galls, 

were rated as culls. Cull rate by treatment is 

shown in Table I. The mean cull percentage was 

10.1 and 13.2 for seedbed densities of 6 and 12 

seedlings / f t \ respectively. The higher cull 

percentage in the highest bed density was caused 

by a greater proportion of seedlings with less 

than 3/16 inch RCD. However, fusiform rust cankers 

caused more culls at either seedbed density than 

did the failure of seedlings to meet morphological 

standards. 

The seven morpllological attributes included 

(1) RCD, (2) total fresh weight, (3) length of 

needles, (4) number of large first-order lateral 

roots (diameter >I mm), (5) arbitrary rating of 

the abundance of fibrous roots as low, medium, 

or high, (6) percent of short roots ectomycorrhizal 

with Pt, and (7) percent of short roots ectomycorrhizal with all fungi. Taproots were cut to a 

uniform length of 10 inches on all seedlings. 

Numbers of first-order lateral roots larger than 1 

mm were included as parameters fo1lowing the 

recommendat ion of Kormanik (1 986). 

Data analysis.--The main effects and interactions of the three nursery cultural treatments 

on the morphological attributes of seedlings were 

examined by analysis of variance (ANOVA), Linear 

correlations among the morphological attributes 

were computed. 

RESULTS AND DLSCUSSIOK 

Effects of nursery cultural practices.--Seedbed density had a highly significant effect on six 

of the seven morphological attributes that were 

assessed. Seedle length, which averaged 18 inches 

for all treatments, was the only measured attribute 

not affected by the nursery cultural treatments. 

Seedlings produced at the 6/ft2 seedbed density 

had 25 percent larger RCD, 56 percent greater fresh 

weight, and nearly twice as many large first-ordzr 

lateral roots as seedlings produced at the 12/ftL 

density. However, a greater abundance of fibrous 

roots and a higher percentage of short roots ectomycorrhizai with Pt or all fungi occurred on seedlings produced at the higher seedbed density 

(table 2). Lateral-root pruning caused an 

increase in the abundance of fibrous roots, 

Relationships arcong rr,orphologicci=ii attributes. - --Linear correlation coefficients among six marphological attributes (excluding needle length) ofthe 1,600 seedlings that were assessed are shown 

in Table 3. Total fresh weight was strongly correlated with RCD (r = +0.82). The number of large 

first-order lateral roots was positively correlated with total fresh weight and RCD, with values 

of +0.79 and 10.77, respectively. The abundance 

of fibrous roots was positively correlated with 

the percent of short roots ecromycorrhizal with 

either Pt or all fungi (r = +0.59 and f0.61, 

respectively). The percent of short roots ectomycorrhizal with Pt was positively correlated with 

the percent of short roots ectomycorrhizal with 

all fungi (r = +0.99). The abundance of fibrous 

roots was negatively related to the number of 

large first-order lateral roots, but the r value 

was only -0.16. 

Table 4 shows the frequency distribution by 

number of lateral roots for the 1,600 seedlings 

in the test, with percentage of seedlings having 

various combinations of fibrous-root abundance. 

For example, seedlings with low abundance of 

fibrous roots coupled with 0-2, 3-5, and 6-8 

larger first-order laterals were 2.69, 6.12, and 

7.69 percent, respectively, or a total of 16.5 

percent of all the seedlings in the test. Only 

9 percent of the seedlings in all fibrous root 

classes had 15 or more large lateral roots. The 

distribution of seedlings by classes of fibrous 

roots was 29 percent with low, 56 percent with 

medium, and 15 percent with high abundance. 

FIELD EXPERIMENT 

Methods 

Study ar-. --The outplanting site was on the 

Savannah River Forest Station, Aiken, South 

Carolina. The soil is Lakeland sand. The srudy 

area was within a larger unit designated for site 

preparation using the "brown and burn" method, 

because it was occupied principally by scrub oaks 

and other unmerchantable hardwoods and shrubs. 

The herbicide Pronone 10-G was applied at 13 lb/ 

acre during May 1985, and the site was burned in 

September 1985. The cost of site preparation, 

$48/acre for herbicides and $10 to $20/acre for 

burning, was much less than an alternate method, 

V-blading and raotraking, with expected costs of 

$170/acre. 

Plantable seedlings were assigned numbers 

indicating their nursery treatment, tagged, packed 

in wet peat moss, sealed in shipping bags, and 

placed in cold storage for 10 days or less until 

removal for planting. Seedlings were machineplanted on December 17, 1985, at approximately 

6x10 foot spacing. 

-- 

Experimental design.--Seedlings were planted 

completely at random in 18 rows without regard to 
nursery cultural treatment. Treated stakes with 

tags were placed beside the lst, 20th, 40th, etc., 

and last seedling on each row. A record was made 

of the seedling number (1-1,600) corresponding to 

each planting position and row number. 

Seedling inventory.--Survival and vigor were 

recorded during September of the first growing 

season. Vigor of surviving seedlings was judged 

on a scale of 1 to 5 as follows: 1 = very poor, 

perhaps dying; 2 = poor; 3 = average; 4 = good; 

5 = excellent, with total height 2 4 inches. 

Data analysis.--ANOVA1s were made of the main 

effects and interactions of nursery cultural 

treatments on survival and vigor in September of 

first year. Linear correlation coefficients 

between survival and vigor as dependent variables 

and morphological attributes as independent variables were computed, and the strongest relationships 

were tested by multiple regression analysis. 

RESULTS AND DISCUSSION 

Spring and early summer of 1986 during the 

first growing season were extremely dry, with a 

rainfall deficit of approximately 10 inches by 

the end of July. Also, the average daily temperature during July was the highest recorded in 

this locality during the past 100 years. Thus, 

it is remarkable that an overall mean survival of 

61.4 percent was recorded in September 1986 near 

the end of the first growing season. 

Effects of nurserv cultural ~ractices on 

field responses.--Both lateral-root pruning and 

seedbed density significantly affected vigor of 

seedlings, but lateral-root pruning was the only 

nursery cultural treatment that significantly 

affected survival. Mean survival was 71.6 and 

51.2 percent for pruned and unpruned seedlings, 

respectively (table 5). Mean vigor ratings were 

also higher for pruned seedlings than unpruned 

seedlings, and seedlings produced at the 6/ft2 

seedbed density had higher vigor than seedlings 

produced at the 12/ft2 density. 

Relation of field responses to morphological 

attributes.--Linear correlations between field 

responses and certain morphological attributes of 

bare-root stock are shown in Table 6. Significant 

positive correlations were found between survival 

and the following attributes: rating of the abundance of fibrous roots; percent of short roots 

ectomycorrhizal with Pt; percent of short roots 

ectomycorrhizal with a11 fungi; and the interaction 

term (rating of the abundance of fibrous roots) x 

(number of large first-order Lateral roots). 

Significant positive correlations were found 

between seedling vigor and the following attributes: RCD; total fresh weight; number of large 

first-order lateral roots; the interaction term 

(RCD) x (number of large first-order lateral 

roots); and the interaction tern (rating of the 

abundance of fibrous roots) x (number of large 

first-order lateral roots). 

Multiple linear regressions with three independent variables, rating of the abundance of 

fibrous roots, number of large first-order lateral 

roots, and (rating of the abundance of fibrous 

roots) x (number of large first-order lateral 

roots) had an R~ value of 0.401 with survival as 

dependent variable and an value of 0.583 with 

vigor as dependent variable. Both of these 

regressions were highly significant. 

Survival and vigor were computed by class of 

fibrous-root abundance and number of large firstorder lateral roots (table 7). Survival was 82 

percent or more for planting stock having a high 

abundance of fibrous roots coupled with six or 

more large first-order lateral roots, and the vigor 

rating for this group of seedlings was above 

average. In contrast, survival was 38 percent or 

less for stock having a low abundance of fibrous 

roots coupled with eight or less large first-order 

lateral roots and the vigor rating for seedlings 

with these attributes was below average. 

Gulling seedlings with certain attributes to 

improve field performance.--Only seedlings that 

did not meet the specifications for Wakeley's 

grades 1 and 2 were culled. If higher standards 

for selecting planting stock had been used, field 

performance might have been improved. If seedlings 

with low abundance of fibrous roots and <9 large 

first-order lateral roots had been culled, the 

resulting cull percentages would have been 10.5 

for seedlings receiving lateral-root pruning and 

22.5 for unpruned seedlings. After such culling, 

the expected survival would have been 75.0 percent 

for pruned seedlings and 57.6 percent for unpruned 

seedlings. After subtracting mean survival for 

the respective treatments (71.6 percent for pruned 

and 51.2 percent for unpruned, table 5) one obtains 

the following increase in survival due to such 

culling: 3.4 percentage points for the lateral-root 

pruning treatment and 6.4 percentage points for the 

unpruned treatment, based on the actual performance 

of seedlings. 

COXCLUSIONS 

Although these results and findings are preliminary, they indicate that nursery cultural 

practices for longleaf pine, especially lateralroot pruning and seedbed density, strongly 

influence field performance. Responses to treatments in the field reflected changes in key 

morphological attributes. These include the 

relative abundance of fibrous roots, the number 

of large first-order lateral roots, and their 

interaction. First-year survival and vigor were 

more closely correlated with these attributes than 

with other seedling characteristics. When highquality seedlings are produced under sound nursery 

managment practices, including fumigating soil, 

inoculating with Pt, ccntrolLing seedbed density 

with a range of 6 to 12 seedlings/ft2, pruning 

lateral roots two or three times during the growing 

season, fertilizing at near optimum levels 

throughout the growing season, and controlling 

pests, then one can expect only a modest increase 

in survival by culling seedlings with undesirable 

morphological attributes. However, important gains 

in field performance are directly attributable to 

improvement in seedling quality by certain nursery 
cultural practices and the resulting alterations 

in key morphological attributes. 

LITERATURE CITED 

Brissette, John 6. Summary of discussions about 

seedling quality. In: Proceedings Southern 

Nursery Conferences, Western Session, 1984 June 

11-14, Alexandria, LA; Eastern Session, 1984 

July 24-27, Asheville, NC. 1985:127-128. 

Kormanik, Paul P. Lateral root morphology as an 

expression of sweetgum seedling quality. Forest 

Science 32 : 595-604; 1986. 

Wakeley, Philip C. Planting the southern pines. 

Agric Honogr. 18. Washington, DC: U.S. 

Department of Agriculture, 1975. 233 pp. 

Hatchell, Glyndon E. Seedling quality and field 

performance of longleaf pine seedlings affected 

by ectomycorrhizae and nursery cultural practices. 

In: proceedings 3rd Biennial Southern Silvicultural Research Conference, 1984 November 7-8, 

Atlanta, GA. 1985:395-402. 

Table 1.--Cull percentage for 1-0 longleaf pine seedlings based on Wakeley's 

(1954) minimum specifications for longleaf pine grade 2 stock, by nursery 

cultural treatment 

Seedbed density, spacing 

between seed drills, and 

lateral root pruning 

Primary reason for culling 

Root-collar Damaged 

Fusiform diameter root Total 

treatment canker <3/16 inch system -- culls 

Cull percentage 

6 seedlings/ft2 

6-inch drills-pruned 

6-inch drills-unpruned 

12-inch drills-pruned 

12-inch drills-unpruned 

Mean 6.3 1.3 2.5 10.1 

6-inch drills-pruned 

6-inch drills-unpruned 

12-inch drills-pruned 

12-inch drills-unpruned 

Mean 6.8 5.9 0.5 13.2 

Table 2.--Means of morphological attributes of longleaf pine bare-root stock 

by nursery cultural treatment 

Root- Total No, 1st- Fibrous % of Short roots 

Treatment collar fresh order root ectomycorrhizal with: 

and level diameter weight 1 azrals rating Pt All fungi 

Inch Gram Number Scale: 1 to 3 - - Percent - - Lateral-root 

pruning: 

Pruned 0.45 87 7.1 2.0 6 0 6 7 

Unpruned 0.45 9 0 7.3 1.7 5 6 6 3 

Seedbed density: 

6/f t2 0.50 108 9.3 1.7 5 4 6 1 

12/fti 0.40 6 9 5.1 2.0 6 2 6 9 

Drill spacing: 

6 inches 0.44 8 6 7 .O 1.9 5 8 6 4 

12 inches 0.45 90 7.4 1.9 59 6 6 
Table 3.--Linear correlation coefficients among morphological attributes of 1-0 

longleaf pine seedlings 

Root- Total No. 1st- Rating X Short % Short 

collar fresh order fibrous roots w/ roots w/ 

diameter weight laterals roots ~t ector all ecto2 

r value and significance level' 

Root-collar 

diameter --- +0.819** +0.770** -0.150** +0.017 4-0.025 

Total fresh 

weight +0.819** --- +0.793** -0.191** -0.076** -0.066** 

No. first-order 

laterals +0,770** +0.793** --- -0.158** +0.006 +0.013 

Rating of fibrous 

root abundance -0.150** +0.191** -0.158** --- +0.593** +0.608** 

% Short roots 

with Pt ecto. +0.017 -0.076** +0.006 +0.593*& --- +O. 992** 

% Short roots 

with all ecto. +0.025 -0.066** f0.013 +O. 608** +O .992*>k --- 

'pt ecto. = PisoZithus tinctorius ectomycorrhizae. 

2~11 ecto. = total ectomycorrhizae formed by all fungal species. 

3** significant at the 1% level; N = 1,600. 

Table 4.--Frequency distribution of the 1,600 longleaf pine seedlings analyzed 

for morphological attributes, by number of large first-order lateral roots and 

the rating of the abundance of fibrous roots 

Abundance of Number of first-order lateral roots >1 mm 

fibrous roots 0-2 3-5 6- 8 9-11 12-14 15-17 >17 Total 

Low 2.69 6.12 7.69 5.06 4.31 2.19 0.75 28.81 

Medium 11.81 12.69 13.25 8.38 5.38 3.37 1.62 56.50 

High 3.81 3.75 3.12 2.44 0.50 0.69 0.38 14.69 

Totals 18.31 22.56 24.06 15.88 10.19 6.25 2.75 100.00 
Table 5.--Mean survival and vigor of longleaf pine seedlings in September of 

first growing season after outplanting on a sandhills site 

Nursery cultural treatment Survival percentage Vigor rating1 

Lateral-root pruning 

Pruned 

linpruned 

Seedbed density 

6/iti 

12/ftL 

Dril l spacing 

6 inches 

12 inches 

Overall means 61.4 3.02 

l~atin~ of seedling vigor: 1 = very poor; 2 = poor; 3 = average; 4 = good; 

5 = excellent (height 2 4 inches). 

Table 6.--Linear correlations between survival and vigor of longleaf pine 

seedlings in September of first growing season and morphological attributes 

of bare-root stock 

Morphological attribute Field response of seedlings after 1 year - 

of bare-root stock Survival Vigor 

-* 

r value and significance level1 

Root-collar diameter 

Total fresh weight 

Length of needles 

Number of strong lateral roots 

Rating of fibrous roots 

% Short roots with Pt ectomycorrhizae 

% Short roots with all ectomycorrhizae 

(Root-collar diameter) x (number of 

first-order lateral roots) 

(Rating of fibrous roots) x (number 

of first-order lateral roots) 

'*$; and 9: significant at 1% and 5% level, respectively; N = 64. 

Table 7.--Survival and vigor of seedlings in September of first growing season, by number 

of large first-order lateral roots and the rating of the abundance of fibrous roots 

Abundance of Number of first-order lateral roots >1 mm 

fibrous roots 0- 2 3- 5 9-1 1 El-8 -- 12-14 15-17 >17 

Survival (Percent) 

Low 

Medium 

High 

Low 

Medium 

High 

Vigor ratingi 

'Rating of seedling vigor: 1 = very poor, 2 = poor; 3 = average; 4 = good; 5 = excellent 

(height _i 4 inches). 
EFFECT OF TIME AND DEPTH OF PLANTING ON SURVIVAL AND GROWTH OF LOBLOLLY PINE 

(PINUS TAEDA L.) SEEDLINGS IN TEXAS 11 

M. Victor Bilan 2 1 

Abstract.--Loblolly pine seedlings were lifted from a nursery bed in 

two-week intervals (November 4-April 21) and were immediately lanced in 

an open field. Each planting included seedlings planted at the root collar 

(A), one-half of shoot buried (B) and most of the shoot buried except for the 

one-inch terminal (C). Average mortality during the first year was lo%, 

13% and 15% for the A, B and C planting depths, respectively; the 

corresponding values for the second year mortality were 22, 3% and 5%. 

Average first year mortality by the planting periods ranged 74 - 24% with 

the highest values for April plantings. Deep (C) planting produced most 

height growth during the first growing season and least during the second 

and third growing seasons. 

INTRODUCTION 

This study was initiated in 1958, during the 

period of intensified interest in survival of 

outplanted southern pine seedlings and in the 

successful establishment of pine plantations. 

Review of then available literature (Ferguson and 

Stephenson, 1955) concluded that some attempts 

have been made to rationalize the results in view 

of weather conditions and morphological 

development of planting stock. Slocum (1951) and 

Slocum and Maki (1956) reported that deep planting 

had some positive effect on growth of loblolly 

pine seedlings, but no literature was available 

dealing with the season of planting. 

Preliminary experiments conducted by the author 

revealed that in East Texas roots of the pine 

seedlings were actively growing in the winter, so 

he had concluded that early planting would enable 

seedlings to develop sufficient root systems 

before the occurrence of the late spring and 

summer droughts. It was, however, necessary to 

determine the time in the autumn when seedlings in 

a nursery were "hardened" enough to be 

transplanted in a field without sustaining high 

mortality. It was also postulated that, other 

factors being equal, pine seedlings with 

well-developed deep-reaching root systems have a 

much better chance of surviving prolonged drought 

than the seedlings with superficial. shallow root 

systems. This study was designed to plant 

seedlings in two-week intervals from November till 

April by using three different depths of 

plantings. 

EXPERIMENTAL PROCEDURES 

The study was established on a Woden sandy 

loam soil of old field in Nacogdoches County, 

Texas. The field was plowed and disked six 

weeks before the establishment of the experiment 

and then it was subdivided into three blocks, 

each 164 feet by 108 feet. Each block consisted 

of 41 rows, each 108 feet long and four feet 

apart. Two edge rows served as isolation strips, 

while the remaining 39 rows represented randomly 

assigned 13 different dates of planting at the 

three different depths. The plantings were made 

in two-week intervals beginning November 4, 1958 

and ending April 21, 1959. Each row in a block 

contained 27 seedlin~s spaced four feet apart 

and planted on the same date and at the same 

depth. Two edge seedlings were considered as 

isolation. 

The depths of planting were as follows: (A) 

root collar at the ground level, (B) one-half of 

the shoot buried, (C) most of the shoot buried 

except for the upper one-inch of terminal. 

Standard planting bar was used for regular (A) 

planting, while 18-inch bar was used for B and C 

planting depths. All roots were trimmed to the 

length of seven inches. 

Statistically, this study consisted of 13 

planting dates and three depths of planting, 

each represented by three replications of 25 

seedlings. All data were analyzed by two-way 

analysis of variance. 

RESULTS 

L/paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

1'~rofessor of Forestry, School of Forestry, 

Stephen F. Austin State University, Nacogdoches, 

Texas 75962. 

Mortality 

Periodic survey of experimental planting 

revealed that by March 19, 1959, attrition due 

gophers and weather damage was 6 percent, 4 

percent and 2 percent in A, B and C planting 

depths, respectively (Table 1). Mortality was 
particularly very high in November 18 planting, 

amounting to 22 percent in A and 16 percent in B 

depth of planting. It is important to notice 

that this planting was made just two days before 

the first freeze of the season, The loss due to 

inclement weather was four times as high as was 

the loss due to the obvious damage by gophers. 

Average annual mortality for 1959 amounted to 

10 percent, 13 percent and 16 percent in the 

planting depths A, B, and C, respectively (Table 

2). Both April plantings suffered very high 

mortality in all depths of planting, averaging 

19 percent, 21 percent and 33 percent in A, B 

and C, respectively, The highest mortality in 

A (25%) and B (27%) depths of planting occurred 

in planting made on November 18, while the 

highest mortality in C (36%) depth of planting 

occurred in April 21 planting. 

Average mortality during 1960 growing season 

was 2 percent in A, 3 percent in B and 5 percent 

in C depth of planting, and no particular 

pattern was noticed in respect to the season of 

planting. 

Seasonal Height Growth 

Average seasonal height growth in 1959 was 

significantly different for each depth of 

planting, amounting to 9 inches in A, 11 inches in 

E and 13 inches in C planting (Table 3). 

Seedlings planted on November 4 grew most, while 

those planted in March and April grew Least, 

regardless of the depth of planting. 

In 1960 and 1961, average height growth of A and 

B plantings was significantly higher than that of 

C plantings (Table 4), but in 1962 growth was 

identical in all depths of planting. Height 

growth of all April plantings continued to lag 

behind all others through 1960 and 1961 growing 

seasons. 

Total Height 

Average height of all A plantings was greater 

than was the height of either B or C plantings 

from 1959 through 1962 (Table 5 and Table 6), 

while average height of all C plantings was 

significantly smaller than that of average B 

plantings. Average height superiority of November 

4 planting was maintained in A plantings 1959 

through 1961 and in B plantings 1959 through 1960. 

During four years of study, average height of 

trees planted in March and April was shorter than 

the height of trees planted in November-February 

in all depths of planting. 

DISCUSSION 

increased height growth during the first year 

only. Deep planted trees were shorter than the 

conventionally planted trees during four following 

years. 

Slocum (1941) and Slocum and Maki (1956) 

reported that deep planting on well-drained clay 

did not effect survival and it increased height 

growth of loblolly pine seedlings through the 

second growing season, but the authors warned that 

similar results might not be expected elsewhere. 

Deep planting reduced survival of loblolly pine on 

droughty sandy loam (Ursic 1963) and poorly 

drained silt and clay soils (Switzer 1960) in 

Mississippi as well. as on sandy loams in East 

Texas (Koshi, 1460). 

The highest mortality in this study occurred in 

the seedlings lifted and planted before the first 

freeze in the fall or after broken shoot dormancy 

in April. It seems that high mortality in 

November 18 planting was caused by the first cold 

spell of the season, while root disturbance of the 

seedlings during the onset of shoot elongation was 

responsible for high mortality in the April 

plantings. Low temperature as the cause of high 

mortality in November 18 planting is supported by 

the fact that mortality was relatively low in the 

C depth of planting where only tips of the shoots 

were exposed to freezing atmosphere. 

Poor survival of loblolly pine seedlings 

lifted prior to dormancy was reported by Venator 

and Barnett (1984), and Brissette and Roberts 

(198h) found less root regeneration potential in 

seedlings lifted in November. Bilan and 

Ferguson (1985) reported that all seedlings 

survived when they were lifted and outplanted in 

a field in two-week intervals December 1 through 

March 2. 

Reduction of height growth in all March and 

April plantings during the first growing season 

resulted probably from the interruption of 

spring shoot elongation. Poor survival of 

loblolly pine seedlings lifted and planted 

during late spring was reported by Dierauf 

(1978) and Venator (1985). The author (Bilan 

and Ferguson 1985) found that loblolly pine 

seedlings lifted and planted in March grew less 

in height by early Nay than did seedlings lifted 

and planted December 1 - January 12. 

The author concludes that loblolly pine 

seedlings have their highest survival ae< aa-1y 

growth potential when they are Lifted and 

outplanted during their dormancy, but the actual 

survival and growth in the field may be to a 

great degree affected by the climatic conditions 

following outplanting, 

Deep planting by burying shoot to one inch 

terminal reduced survival during the first two 

years and resulted in less height growth during 

the second and third year. The increased height 

growth during the first year did not compensate 

for less growth during the second and third year. 

Burying one-half of the shoot reduced survival and 
Table 1. Average Attrition of Seedlings Due to Gophers and Weather by Time and Depth of Planting by 

March 19, 1959. 

Planting Depth A Planting Depth B Planting Depth C 

DATE 

PLANTED GOPHER DEAD TOTAL GOPHER DEAD TOTAL GOPHER DEAD TOTAL 

- - - - - PERCENT - - - - - 

NOV. 4 1.3 11.7 13.0 1.3 3.9 5.2 1.3 1.3 2.6 

18 3.9 18.2 22.1 2.6 13.0 15.6 1.3 0 1.3 

DEC. 2 3.9 6.5 10.4 1.3 2.6 3.9 1.3 0 1.3 

16 1.3 1.3 2.6 1.3 0 1.3 2.6 2.6 5.2 

3 0 1.3 3.9 5.2 1.3 2.6 3.9 1.3 1.3 2.6 

JAN. 13 0 1.3 1.3 0 1.3 1.3 0 0 0 

2 7 0 1.3 1.3 0 0 0 1.3 0 1.3 

FEB. 10 0 1.3 1.3 0 0 0 1.3 0 1.3 

14 0 0 0 0 0 0 0 0 0 

AVERAGE 1.3 5.1 6.4 0.9 2.6 3.5 1.2 0.6 1.8 

Table 2. Average Annual Mortality of Loblolly Pine Seedlings by Time and Depth of Planting During 1959 

and 1960. - DATE Plantl-Q Depth Planting Depth 

PLANTED d 

- B C A B C 

1959 1960 

7, - - PERCENT- - - - 

NOV. 4 7,4c1" P6,Cb 12.3b 2.5 2.5 5.0 

18 24.7a 2", 2a 9.9b 0 3.7 2.5 

DEC. 2 9,9bc 4,9c 9.9b 0 1.3 5.0 

16 6*2c 4.96 14.8b 0 4.9 2.5 

30 7,4c lL6bc 17.3b 2.5 0 7.4 

JAN. 13 2,5c -3 . 9 c: 14.8b 3.7 3.7 2.5 

27 4,9c 4,9c 9.9b 1.3 1.3 2.5 

FEB. 10 4,9c 7.4~ 7.4b 6.2 7.4 8.6 

2 4 il.Shc 8, Bs, 9.9b 1.3 2.5 7.4 

MAR. 10 2 Sic 22,0ab 18.5b 3.7 7.4 3.7 

24 7.4~ 11, ic 13.6b 1.3 3.7 0 

APR. 7 21.0ab 7L.2ab 30.9a 0 0 11.1 

2 1 17.3ab 19.8ab 35.821 2.5 2.5 3.7 

AVERAGE FOR 

PLANTING 

DEPTH 10.3a 13.2b 15.8~ 1.9a 3.2ab 4.8b 2 1 

Values in individual columns for year 1959 followed by the same letters are not statistically 

different at the 95 percent confidence level by Duncan's multiple range test. 

Average values for planting depth for 1959 and 1960 followed by the same letter are not statistically 

different at the 95 percent confidence level by Duncan's multiple range test. 
Table 3. Average Annual Height Growth of Loblolly Pine Seedlings by Time and Depth of Planting for 1959 

and 1960. 

DATE Planting Depth Planting Depth 

PLANTED A B C A B C 

1959 1960 - IXCHES - - 

NOV. 4 14.4 - a 16.8a 16.7a 31.6a 31.0a 28.8a 

18 9.8'0 12.3b 14.4a 28.4~3 30.3a 29.4a 

DEC, 2 10.7b 12. lb 14.5a 30.8a 29.6a 29. la 

16 10.6b 12.8b l4.5a 29.8a 30.4a 28.4a 

30 9.lb 12.2b 13.8b 29.8a 31.4a 29.7a 

JAN. 13 12.3a 14. lb 15.3a 30.6a 32.la 29,6a 

2 7 10.2b 12.5b 15.2~1 29.9a 30.5a 30. la 

FEB. 10 10.5b 13. lb 13.2b 32.8a 30.5a 29.9a 

2 4 7.9bc 11.7b 10.6~ 29.2a 27.6b 28. la 

MAR. 10 5.5~ 7.9~ 10.3~ 28.0~1 24.7s 27. la 

2 4 6.7~ 8.3~ 10.2~ 29.2a 29.7a 28.8a 

APE. 7 4.7~ 7.6~ 9.0~ 26.3b 26.3s 23.8b 

2 1 6.4~ 6.9~ 8.7~ 25.2b 25.3b 25.9b 

AVERAGE 

FOR PLANTING 

DEPTH 9.lc 11.4b 12.8a 29.3a 29.2a 28. lb 2 1 

Values in individual columns followed by the same letter are not statistically different at the 95 

percent confidence level by Duncan's multiple range test. 

'/ Average values for planting depth within years filler by the same letter are not statistically 

different at the 95 percent confidence level by Duncan's multiple range test. 

Table 4. Average Annual Height Growth of Loblolly Pine Seedlings By Time and Depth of Planting for 1961 

and 1963. 

Planting Depth Planting Depth 

DATE 

PLANTED A B C A B C 

196 1 1962 

NOV. 4 

18 

DEC. 2 

16 

3 0 

JAM. 13 

2 7 

FEB. 10 

2 4 

MAR. 10 

2 4 

APR. 7 

2 1 

AVERAGE FOR 

PLANTING 

CHES 

48.5a 

50.5a 

49.6a 

48.4a 

50.7a 

49.6a 

50.9a 

50.6a 

50. la 

49.8a 

50,7a 

47.6a 

50.3a 

- 

52.0a 

47.2ab 

50.4ab 

51.0a 

51.la 

46.7b 

50.6ab 

52. la 

48.7ab 

49.2ab 

50. lab 

47.8ab 

46.9b 

DEPTH 46. 6aL/ 46.7a 45.2b 49.9a 50. la 49.5a 

Values in individual columns followed by the same letter are not statistically different at the 95 

2/ percent confidence level by ~uncan's multiple range test. 

Average values for planting depth within years followed by the same letter are not 

statistically different at the 95 percent confidence level by Duncan's multiple range test. 
Table 5, Mean total height of loblolly pine seedlings by time and depth of planting in 1959 and 1960. 

Planting Depth Planting Depth 

DATE 1959 f 960 

PLAHTED A B C A if C - - INCHES - - NOV, 4 24.4a 21.8a 17.7a 56.0a 52.8a 46.5a 

18 19.8b 17.3b 15.4a 48.2b 47.6b 44.88 

DEC. 2 20.7b 17. lb 15.5a 51.5b 46.37 Lt4.6a 

16 20.6b 17.8b 15.5a 50.4b 48.2b 43.9a 

30 19.4b 17.2b 14.8a 49.2b 48.6tr 44.5a 

JAN. 13 22.3ab 19. lb 16.3a 52.9b 51.2b 46.4a 

2 7 20.2b 17.5b 16.2a 50. lb 48.0b 46.3a 

FEB. 10 20.5b 18. lb 14.2a 53.3b 48.6b 44. la 

2 4 17.9bc 16.7b 11.6~ 47. lbc 44.3bc 39.713 

MAR. 10 15.5~ 12.9~ 11.3b 43.5~ 37.6~ 38.4b 

24 16.7~ 13.3~ 11.2b 45.9~ 43.0bc 40.0b 

APR. 7 14.7~ 12.6~ 10.0b 41.0~ 38.9~ 33.8b 

2 1 16.4~ 11.9~ 9.7b 41,6c 37.2~ 35.6b 

AVERAGE BY 

PMTIMG 

DEPTH 2 1 19.2 a 16.4b 13.8~ 48.5a 45.6b 42.2~ 

Values in individual columns followed by the same letter are not statistically different at the 95 

percent confidence level by Duncan's multiple range test. 

2/ Average values for planting depth within years followed by the same letter are not statistical 

different at the 95 percent confidence level by Duncan's multiple range test. 

Table 6. Mean Total Height of Loblolly Pine Seedlings by Time and Depth of Planting in 1961 and 1962. 

Planting Depth Planting Depth 

DATE 

PLANTED A B C A B C 

1961 1962 

NOV. 4 

18 

DEC, 2 

16 

30 

JAN. 13 

2 7 

FEB. 10 

2 4 

MAR. 10 

24 

APR. 7 

2 1 

AVERAGE FOR 

INCHES 

93.0a 154.5a 

91.6a 144.5b 

92.9a 148. lb 

91.0a 144.6b 

91.8a 146.3b 

91.2a 150.5a 

95.5a 150.8a 

89.6a 150. %a 

82.8b 143.4b 

82.3b 138.0~ 

83.5b 144.3b 

75.8~ 132. lc 

75.5~ 135.8~ 

PLANTING 

DEPTH 2 1 95.1 a 92.3b 87.4~ 144.9a 142.313 137. Oc 

Values in individual columns followed by the same letter are not statistically different at the 95 

percent confidence level by Duncan's multiple range test. 

2/ Average values for planting depth within years followed by the same letter are not statistically 

different at the 95 percent confidence level by Duncan's multiple range test. 
LITERATURE CITED 

Bilan, M.V. and E.R. Ferguson. 1985. Root 

regeneration in outplanted loblolly pine 

(piaus taeda L.) seedlings. Proc. Internat. 

s-ium Hursery Management Practices for 

the Southern Pines, Montgomery, Alabama, August 

4-9, 1985. 

Brissette, J.C. and T.C. Roberts. 1984. 

seedling size and lifting date effects on root 

growth potential of loblolly pine from two 

Arkansas nurseries. Tree Planters' Notes 

35 (1 ) : 34-38. 

Dierauf, T.A. 1978. Problems with seedlings 

dormancy and freezing. Proc. 1978 Southern 

Nursery Conf. U.S.D.A. For. Serv., Tech. Publ. 

SA-TPG, p. 42-47. 

Ferguson, E.R. and G.K. Stephenson. 1955. Pine 

regeneration problems in East Texas: a 

project analysis. U.S. For. Serv., So. Expt. 

Sta. Typed office report, 10pp. 

Koshi, P.T. 1960. Deep planting has little 

effect in a wet year. U.S. For. Serv. Tree 

Planters' Notes 40:7. 

Slocum, G.K. 1951. Survival of loblolly pine 

seedlings as influenced by depth of planting. 

Jour. Forestry 49:500. 

Slocum, G.K. and T.E. Naki. 1956. Some effects 

of depth of planting upon loblolly pine in 

North Carolina Piedmont. Jour. Forestry 

54:21-25. 

Switzer, G.L. 1960. Exposure and planting depth 

effects on loblolly planting stock on poorly 

drained sites. Jour. Forestry 58:390-391. 

Venator, C.R. 1985. Evidence for lifting window 

in loblolly pine nursery seedlings. Proc. 1984. 

Southern Nursery Conf. July 25-27, 1984, 

Asheville, N.C. 

Venator, C.R. and J.P. Barnett. 1984. Relating 

root growth potential to survival and growth of 

loblolly pine seedlings. Proc. Third Biennial 

Southern Silvicultural Research Conference, 

Atlanta, Georgia, November 7-8, 1984: 125-127. 

Ursic, S.J. 1963. Modification of planting 

technique not recommended for loblolly on eroded 

soils. Tree Planters' Notes 57:13-17. 
1 / ANNUAL AND GEOGRAPHIC VARIATIONS IN CONE PRODUCTION BY LORGLEAF PINE21 William D, BoyerAbstract--Cone production by longleaf pine (Pinus 

palustris Mill.) has been monitored on sample trees in 

shelterwood stands since 1966. Eleven locations, three eachin Alabama and Florida and one in Louisiana, Mississippi, 

Georgia, South Carolina, and North Carolina were included in 

the study. Each 1ocation.had two test areas, with 50 sample 

trees each. Six locations had 15 or more years of record, 

the others less. Annual counts of cones, conelets, and 

flowers (pistillate strobili) on each sample tree were made 

until trees were cut. Over 20 years, cone crops in which the 

average number of cones per tree exceeded 50 occurred only 

in 1967, 1973, and 1984. The frequency of cone crops 

potentially useable for natural regeneration (average of 20 

or more cones/tree) varied considerably among locations. 

Cone crop frequency was very low (< 0.1 or 1 year in 10) at 

two locations in northwest Florida and one in southwest 

Georgia. Cone crop frequency reached a peak of 0.62 and 

0.75 at two locations in central Alabama. The ratio of 

flowers counted to cones produced suggests that low cone 

crop frequencies near the Gulf Coast were due more to flower 

losses than failure to produce flowers. 

INTRODUCTION 

Longleaf pine is a poor seed producer compared 

to other southern pines, and cone crops good 

enough for natural regeneration are relatively 

infrequent (Boyer and Peterson 1983). Wahlenberg 

(1946) noted that good crops occur every 5 to 7 

years, and failures about 1 year in 5. In south 

Mississippi over a period of 21 years, there were 

9 years in which medium or better cone crops 

occurred in longleaf pine (Maki 1952). 

Shelterwood stands in south Alabama produced 5 

cone crops adequate for natural regeneration 

0 50 thousand seedslacre) over a period of 19 

years (~roker and Boyer 1975). Heavy or bumper 

seed crops through much of the range of longleaf 

pine may occur once in 8 to 10 years (Maki 1952). 

Very few systematic observations of cone production by longleaf pine have been reported, (e.g., 

Croker 1973, McLemore 1975). These are normally 

from a localized area and cover only a few years. 

A region-wide test of the shelterwood system of 

natural regeneration of longleaf pine was 

1/peper presented at the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-5, 1986. 

Z/l?roject Leader, George W. Andrews Forestry 

Sciences Laboratory, Auburn, AL, maintained by 

the Southern Forest Experiment Station, Forest 

Service, USDA, in cooperation with Auburn 

University. 

initiated in 1966. Data obtained on cone and 

flower production at test sites have provided 

information on the variability of longleaf pine 

cone production over a period of time among 

several locations across the southeastern United 

States. 

METHODS 

Natural regeneration tests for longleaf pine 

were established at 11 locations ranging from 

Louisiana to North Carolina (table 1). One test 

location was the Escambia Experimental Forest, 

Escambia County Alabama; four were National 

Forests in Louisiana, Mississippi, Alabama, and 

Florida; three were State forests in Florida, 

South Carolina, and North Carolina; two were 

private lands (Alabama and Georgia); and one was a 

military reservation (~lorida). 

At each of 10 locations (the experimental forest 

excluded), 2 test areas ranging from about 20 to 

60 acres in size were established. One tested the 

two-cut and the other the three-cut shelterwood 

system. These tests were initiated from 1966 to 

1970. Several two-cut tests were located on 

experimental forest sites, All tests were located 

in maturing stands of longleaf pine nearing end of 

a sawlog rotation. Within each test area, 25 

sample points were established. The two seed 

trees nearest each sample point were marked for 

annual springtime counts of flowers and conelets 

using the method described by Croker (1971). 

Cones produced the preceding fall by each sample 

tree were also counted at the same time. This 
- - -- - --. UL*".. "I' 

longleaf pine cone production 

State County Years of observation 

LA Grant 15 

MS Perry 8 

AL Coosa 8 

Perry 

Escambia 

FL Santa Rosa 

Okaloosa 

Leon 10 

G A Decatur 19 

S C Chesterfield 15 

NC Bladen 8 

was the total of cones on the ground under the 

tree, plus a binocular count of cones remaining in 

the tree. Sample trees were not replaced when 

removed through thinning or natural mortality. 

The number of residual sample trees had dropped to 

less than 20 on only one area. 

'; 0 ------- ------- -- ---.-- ---- ---- 

Lne sampilng period reported here covers the 20 

years from 1966 through 1985. Five locations were 

represented in the first year, and also the last. 

The number of years of cbservation at each of the 

11 locations is given in table 1. The 20 years 

and 11 locations covered in this report result in 

a total of 220 cells. Of these, 144 included at 

least one observation (one test area). A total of 

110 had two observations (both test areas at a 

location) and 7, all on the Escambia Experimental 

Forest, included observations from 3 test areas. 

RESULTS 

Annual Variation in Cone Production 

Cone production by longleaf pine at all locations 

combined, in terms of average number of cones per 

tree, ranged from a low of 1 in 1966 to a high of 

66 in 1973 (fig. 1). Cone production exceeded an 

average of 50 cones per tree only in 1967, 1973, and 

1984. Cone production averaged less than 20 cones 

per tree in 13 of the 20 years and less than 10 cones 

per tree in 9 of the 20 years. Normally, an average 

of 750 cones per acre is needed to obtain adequate 

natural regeneration in a longleaf pine shelterwood 

stand. Shelterwood stands in this study averaged 

about 30 trees per acre, so an average of 25 cones 

per tree would be required for successful regeneration. Anything less than 20 cones per tree is 

likely to be ineffective. 

--.-.--_I_.-- --I _X____I_I-_-_ _-___I_I ___ _ 

k'E.4R S 

Figure 1.--Annual variation in cone production by longleaf pine for all locations combined. 
Variation among Locations in Cone Production Table 2.--Longleaf pine cone production by location 

Average annual cone production per tree varied 

considerably among the I1 locations (table 2). 

The two locations in the Mountain Province of 

Alabama had the highest average cone production, 

with 71 and 86 cones per tree. Locations in 

northwest Florida and southwest Georgia had the 

lowest cone production. 

Data on average annual cone production were 

derived from all sample trees for each year of 

observation. The years of observation varied 

among locations, and there were also differences 

among locations in seed-tree size, which affected 

cone production. A11 I1 locations provided cone 

production data for the 5 years from 1969 to 1973, 

inclusive. For these years, cones produced by 

sample seed trees in the 11- and 12-inch diameter 

classes only (10.6-12.5 in d.b.h.1 were determined. This provided for a direct comparison of 

cone production among locations (table 2). Again, 

two northwest Florida sites and the southwest 

Georgia site had the lowest cone production. 

The practical application of natural regeneration methods for longleaf pine depends on the 

frequency of cone crops large enough to provide 

acceptable regeneration. Considering an average 

of 20 cones per tree as a minimum, the frequency 

of cone crops this large or larger was determined 

for each location (fig. 2). These ranged from 

0.75 and 0.62 for the two Mountain Province locations to 0, 0.06, and 0.07 for the three 

Cones per tree 

A11 trees, 11-12 in d.b.h. 

State County all years trees, 1969-73 

- 

------- Average number --------- 

LA Grant 3 3 14 

MS Perry 16 3 3 

BL Coosa 

Perry 

Escambia 

FL Santa Rosa 7 9 

Okaloosa 4 7 

Leon 19 12 

G A Decatur 3 5 

SC Chesterfield 30 21 

NC Bladen 7 17 

Florida-Georgia sites. The overall average 

frequency of useable cone crops was 0.30 or one 

crop every 3.3 years. A11 locations with cone 

crop frequencies of 0.10 or more have been 

successfully regenerated (6,000 or more established 

seedlings per acre), although sometimes this has 

Figure 2.--Frequency of acceptable cone crops in longleaf pine. 
beeu accomplished by two or more smaller cone crops 

(15-20 conesftree) rather than a single large cone 

crop. The three locations with cone crop frequencies 

of less than 0.10 have not yet been regenerated. 

Low cone crop frequencies could be due to failure 

of trees to flower or to loss of flowers and developing cones, or both. Flower counts (annual 

averageltree) are given in table 3. Cone counts on 

each area were compared to associated flower counts 

obtained from the same trees 2 years earlier and to 

conelet counts obtained 1 year earlier. The ratios 

of flowers to cones and conelet to cones were then 

determined (table 3). Cone crops on each test area 

during the first 2 years of observation were not 

counted at the flower stage, so ratios could not be 

determined for these years. For example, cones 

counted in the spring of 1967 were from the 1966 

cone crop, but the flowers counted at the same time 

represented the 1968 cone crop. 

Table 3.--Average annual flower counts and ratios 

of flowers to cones and conelets to cones 

Avg. No. 

flower Flowers Conelets 

State County countsftree /Cones /cones 

LA Grant 

NS Perry 

AL Coosa 

Perry 

Escambia 

FL Santa Rosa 

Okaloosa 

Leon 

G A Decatur 

SC Chesterfield 

NC Bladen 

Flower production among the 11 locations was much 

more uniform than the resulting cone production 

(coefficient of variation of 41 percent for flowers 

vs. 106 percent for cones). The ratios indicate considerable variation among locations in both flower 

losses during the first year and losses of developing 

cones during the second year (table 3). Higher 

values indicate greater losses. The highest flower 

losses were recorded at two Florida sites plus the 

Georgia site. These same sites also had higher than 

average losses of developing cones. Conversely, the 

high cone-producing sites in Coosa and Perry 

Counties, Alabama had the lowest losses of both 

flowers and developing cones. 

An analysis of variance of all data on flower and 

cone counts i idicated that for flowers, the variation 

associated with year (33 percent) was nearly double 

that associated with location (18 percent). For 

cones, the vav.iation associated with location 

(26 percent) was greater than that associated with 

year (18 percent). Flower production is highly 

variable from year-to-year, and in large part this 

reflects climatic conditions before initiation, 

Flower losses, however, appear to be associated 

with location, being more severe some places than 

others. Final cone crop size, therefore, reflects 

factors affecting initial flowering and also 

flower and cone losses. 

CONCLUSIONS 

Production of longleaf pine cones varies 

considerably from year-to-year and from place-toplace. Considering the region as a whole, the 

frequency of cone crops large enough to establish 

natural regeneration in shelterwood stands is 

almost 1 year in 3. Among the locations sampled, 

however, frequency of useable cone crops ranged 

from 3 years out of 4 to zero. Three locations 

had cone crop frequencies of less than 1 year in 

10. At locations such as these, natural regeneration of longleaf pine may not be a viable option. 

Over time, flower production is more consistent 

among locations than cone production. The 

evidence in this study suggests that low cone 

production is associated more with flower losses 

and, to a lesser extent, cone losses than with 

failure to flower in the first place. 

LITERATURE CITED 

Boyer, William D.; Peterson, Donald W. Longleaf 

pine. In: Burns, Russell M,, tech. comp. 

Silvicultural systems for the major forest 

types of the United States. Agric. Handb. 445. 

Washington, DC: U.S. Department of Agriculture; 

1983: 153-156. 

Croker, Thomas C., Jr. Binocular counts of 

longleaf pine strobili. Res . Note SO-127. 

New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1971. 3 p. 

Croker, T.C., Jr. Longleaf pine cone production in 

relation to site index, stand age, and stand 

density. Res. Note 50-156. New Orleans, LA: 

U.S. Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1973. 3 p. 

Croker, Thomas C., Jr.; Boyer, William D. 

Regenerating longleaf pine naturally. Res. Pap, 

SO-105. New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1975. 21 p. 

Maki, T.E. Local longleaf seed years. Journal of 

Forestry. 50(4): 321-322; 1952. 

McLemore, B.F. Cone and seed characteristics of 

fertilized and unfertilized longleaf pines. 

Res. Pap. SO-109. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1975. 10 p. 

Wahlenberg, W.G. Longleaf pine. Washington, DC: 

Charles Lathrop Pack Forestry Foundation in 

cooperation with U.S. Department of Agriculture, 

Forest Service; 1946. 429 p. 
Abstract .--KultipLc sced lots of longleaf 

(Pinus galustr is >Lil:.), shortleaf (x, cchinata 

Mill.), 'Virginia (0. virsinians Mill.), znd 

ezstern white (2. strobus L.) jines were used 

to evalur;te r.lcasure.,ents of sced vigor lor prediction of seedling ilsterGence in nursery Sel envirur-meuts. Thc highest corrcLations ~lth seedlia:, einergenck were obtained vith the germination 

iest praneters--pert errt 2err:ination and peak 

value and with electriczl cond~ctivity .i cssurements of seed leac'?ate with thr ASLZC-?3i:O Scled 

Analyzer. Correlation coellicients dilf ered only 

slightly. Conducticlty .aeasurenent-, were best 

for sitortleal, Yirginis, and eastern white pines 

(r= 0.790, 0.774, and -3.385), and germination 

test porscleters were best ;or longleaf (r= 0.258 

and 0.?57). In 'ive oT six tests, percent Ger3ination and -eak va ice Kcre .xore hi;l11y correlated with in ergence than '32&b2 tor 'S 

germJnatlon vcllue. T' t da~a suggest that these 

four sbe~les are siml Lir to other sojthern pines 

In test rcspnses. A good lzboratory test is 

desirable, hit thc \onductlvity test is ar, ~ble 

substitute when ti r I :in:iting. Inter;,retztion 

o: the test resuits lo; d;,tixur utilizztTon oi' 

seeds in nurseries is Ilscussed. 

The frequent inability of laboratory gerrlicetion tests to accurately predict nursery .erninat ion 

has been a co,,irnon prob1ei.t for nursery rnan,;;crs. 

\:hen field con3itions a;e favorable, thtre are 'ew 

-,roble;ns. Eut x1,en Led envizon:~ents are stress'ii:, 

standard, &ernrination test 2ercentates mzy not be 

cde,uate predictors oT seed perfor~iance. 

S~rnett and KcLcnore (1984) concluded that gerrnination tests to accurately predict nursery tern~ination percentages were the best ~redic tors oZ seedling production in stratified loblolly (Pinus -- taed~ 

L.) anJ slightly dormant slash pine (2. elliotti 

Cnge:m) , znd th;t CzaSntor 's gernina tion value (3) 

(Czabator 1352) ;:as best Lor dormant or slowly germin&tin~ lor .. Earlier work in our laboratory 

(Bonner l4l35) agreed with the use o, serrnination 

percentages, but we Iound peak value (?V) , another 

Czabator prazeter, to he a Zetter r;re;ictor tlian YV. 

I : 

- Paper ?resented at Fourth Biennial Sout'lern 

5 iLviculturzl Research Son,ercnce, i-tlanta, "eorgia , Sovcrnber 4-5, 1925. 9 / ki i'lsnt Physiologist and ?roJ ec t Leader, Zotl therl: 

Forest Experiment Station, C.S. L'e~artnent of A-rlcult-re, Yorest Service, Stzrkville, -'Z 23759. 

Leachat e conductivity ncasurenents were also vcr; 

?-ror;iisin;: Tor lob1011;; and slasl; gines (33nr1er 13C L) , as weli as Tor some ot!icr eoni;ers (Bonntr and 'Jozzo 

i986). 

3ttl~~ SOU thern gir,cs have heen included in re-- 

search on seed vigor test aetho2s at the author's 

labora~ory Froi;, 137 i, to 1%;. 'i'hls paper summarizes 

results obtained in 19C3-85 with <our of them: Ion;- 

leaf (2, palustris Hill.), shortleaf (2. echinatn 

:lill.) , 'Jirginia (?. - vir~iniana IPIi.11.) , and eastern 

white (2. strobus l.) pines. 

Xu",ip!e seed lots ol varying ases and geogrzpllic sources were ~ssembled for testin;;. Until 

used, they were stored at 3'~ with moisture contents 

of 10 percent cr lower. Samples were taken from as 

many as 22 and ~s few ss 1C sced lots of each 2 

years. Sorle seed lots : -re used in bot!i yezrs. 

S,a!ii.ratory o,rrminatlon, leachate conductivity, tetrzTo1ium stainin; i longlea5 clnd eastern wl~ite pines 

only), ant nursery sernination tests were conducted 

on a:: lots. I'k correlation o: tcst ;;rarncters 

with nursery emergence as used to evsluate the 

ef ies-tlveness of the tests. 

!,,Larator;. gerninaticn.- Cer:r,Ln,t ion tests were 

CL -rid out under off icial test conditions (hrsociatl~n u5 3fEicizl Seed Analysts 137Cj. Four 
replications of 50 to 130 seeds each were germinated 

in cabinet germinators on moist blotters for 28 days. 

Test temperatures were 30OC for 8 hours of light, 

rollowed by 16 hours o: darkness at Z~~C. Sermination was counted a minimum oE three times a week to 

"cilitate calculation oZ rate parameters. In Czabator's formula, PV is the highest quotient obtained 

by dividing cumulative percent germination on each 

day by the number of days elapsed. This value on 

the last test day is the mean daily germination 

(IDG) ; thus, GV = (E"7) (PIDf) . 

Eastern white pine was stratified for 28 days 

at 3OC, but longleaf received no stratification. 

Virginia and shortlea2ppie seeds were stratilied 

for 14 days at 3'~ in the 1984 tests. These species 

received no strati:ication in the 1985 tests because 

the treatment was detrimental to the lower quality 

seed lots in 1984. 

teachate conductivity.- Samples of 100 seeds 

(four per lot) were leached in deionized water Tor 

24 hours at room temperature. Current flow (yamp) 

through the leachate of individual seeds was measured 

with an automatic seed ayjlyzer manufactured by 

Neogen hod Tech., Lnc . , - Ilodels 610 and ASAC-1000 

were both used, but primarily the latter. Eeans and 

standard deviations of conductivity and germination 

estimates based on the histogram segment (11s) method 

were calculzted as described by Eonner and Vozzo 

(19g6). 

Tetrazolium staining (TZ) .- Seeds from 50-seed 

samples were cut down one side with fingernail clippers and soaked in deionized water lor 24 hours at 

room temperature. Then they were placed in a 0.5- 

percent solution 02 2,3,5-triphenyl tetrazolium 

chloride, pH 6.5 to 7.0, at 20°C for 18 to 24 Ilours 

in the dark. Seeds were scored as "good" or "bad" 

according to the criteria oi Ploore (1971), and vigor 

was expressed as the percentage of "good" seeds in 

the sample. TZ staining was used on longleaf and 

eastern white pines in 1 year only. 

Nursery emergence. - Four 50- or 100-seed samples 

were planted in completely randomized rows in nursery beds at the 7orestry Sciences Laboratory. 

LongleaE seeds were sown on the surrace and pressed 

into the soil with a board. The other species were 

planted about 3 mm deep. A11 plots were mulched 

with chop~ed pine straw and protected by bird netting. Eastern white pine was stratizied 2C days at 

3'~. Virginia and shor tleaf pines were stratified 

14 days in the 19C4 tests and 21 days in the 13C5 

tests. Longleai received no stratirication. All 

tests were planted in A~ril, and emerging seedlings 

were counted one to three times per week until 

emergence was complete. 

Hention of trade means is for information 

only and does not imply endorsement or recommendation by the U.S. Department oE Agriculture of any 

product or service over others that may also Se 

available. 

Data analysis .- Correlation coeflic ients bet~jeen test 

parameters and nursery emergence were calculated, 

and si~nificance was tested with the "t" test 

(p=0.05). ide assumed that the test parameters that 

xere coiisistently significantl;. correlated with nursery emergence should be considered as valid estimates ohseed vigor. 

Longleaf pine. - Loth laboratory ~ermination and 

leachate conduct5vlty estimates showed strong significant correlations with nursery emerbence and 

survivsl in the first test year (ta%le I.) In the 

second year, all "r" vvnlues were lower, and germ;- 

nation test parameters were much Setter than those 

in other tests. hlrllo~g!~ 'I Z staining ;?as signi:icantly correlated with nursery iactors in 3.3E3, t!le 

test was dropped Zrom :irrtIler consideration because 

oT the difficulries encountered in stanisrlizinb 

interpretation oz staining gatterns. The iii,hest 

"r" values oStained were from percent kermination, 

mean conductivity, and PV. 

Shortleaf pine.- Sursery germination was so 

poor in 1984 tha-o measurements ucre taken. In 

the 1985 test, signiLLcant correlatious xith nursery 

perforniance were o5tained Lrom percent berminztion, 

PV, GV, and germination estimates from leachate conductivity (table 2). Conductivity estimates Gave 

the :lig,lzest "r" values, then ?V. 

- Viainla pine.- 2.esults with S'irginia pine were 

very similar to those obtained with shortleaf pine 

(table 2). ALtcr nursery test Iailure in 19C4, the 

2325 results showed the highest "r" values Zror tonduc tivity estimates. All laboratory ~ermination 

test parameters were also slgniZicantly correlated 

with emergence and survival. 

Eastern i~hite pine.- Leachate conductivity and 

laboratory gcr~inat ion parameters showed significant 

correia t ions t\ri~!i emergence and survival in the nursery plots (table 3). The highest "rs" values were 

obtained with mean cond~ictivity Tor ecergence in 

both years and with percent germination for survival 

in 1931. Tizrre was little diIlerence among these 

values, hovev er , Among germinat ion test pcramet er s, 

percent germinat ion and F1? coeLLicients were always 

higher than the coe:: ic ients :or ZJ. 

gesults irom these tests were very sirnilzr to 

results reported previously for loblally and slash 

pines (Bonner 1926) . Laboratory germlna tion parameters and leachate conduc tit3ity measurements were 

about equal in their correlation with nursery emergence. 

Standard, but tine consuming, laboratory tests 

are always desirable Tor praper seed management decisions, but rapid esti~ates oZ seed quality zLso 

have their place. in many sit~atfons, seeds must be 

planted or shipped before a i;cri,iination test ccn Le 

scheduled and cornpleced, Leachate conductivity tests 

ccn s;~arently :ill that need. 3ther rapid tests, 

such as TZ or X-ray, may be just as accurate, but 

eacli has serious drawbacks ir? sribJ ec tive int eryretation or time-consuming nethodology , 
i abbe l . --Correlation coeif icients (r) between vigor estimates 

and nursery emergence and survival for lon~lea; pine 

1083 13C4 

?ere ent F ercent Percent ?ercent 

Vigor es timate-5' mergence emergence emergence survival 

Percent germinat ion 

c it 

P t'

Gvnduc t ivity mean 

Conductivity S? 

Condtic tivity :=; 

A v ', rz 

- 

a; GV, germination value; P7, peak value; Gonductivitj-, S!: 

(standard deviation), 9S (histogram segment) ; TZ, tetrazolium staining. 

9: Signiiicant at p = 0.05. 

Table 2 ,--Correlation coefficients (r) between vigor est irnates 

and nursery emergence and survival ior shortlea; and 

Virginia pines in 1985 

Shor leaf 'Jirginia 

Percent Percent Fercent Fesc ent 

Vizor estimates emergence survival emergence survival ---------------------r-------------------- 

Percent germination 0.744* 0.61C9~ 0.697% 0.5839: 

SV 6 2 2 9: .540"' 588 ;'; 57 (j;? 

? v 7 48" 647 fi 67 6;'; 7 659~ 

Conductivity MS 7 90" . 67 5;k 7742 6: ij9~ 

Table 3 .--Correlation coefficients (r) between vigor estimates 

and nursery emergence and survival for eastern white 

pine S/ 

1983 1984 -- 

Percent Fercent Percent Perc t3nt 

iv-igor estimates emergence survival emerLence survival 

----------------------r-------------------- 

Percent germination 0.857;k - - 0.645:k 0.748" 

3 78 49; - - 7279; 622" 

P {v' . s 60;: -- 7 94"i .669* 

Condrrc tivity mean -.869J: -- - .3882 - 726;'; 

Gvnduc tivity SD - 545"" - - - 591;" -.424 

Condrlc t iv ity I-IS - - -- 717" ,593" 

?r Z .20e -- - - -- 

- 

a/ t<o scrvival corjnts were taken in i933. 

5 SigniCicant at p = 0.05. 
In five o: the six primary tests in these 

studies, percent germination and ?V were more highly 

correlated (larger "r" values) with seedling emergence than SV. The same was true with loblolly and 

slash pines (Bonner 1986), although diiierences Tor 

all six species ;?ere very small, 3ther researchers 

have shown a direct relationship between germination 

rate and seedlini; quality of southern pines (Boyer 

and others 1965; Barnett and ?icLemore 1984; Ljasser 

1978). Theregore, it seems there are good reasons 

for making mare use of germination rate in evaluation oi seed lots. 

Under the conditions og these studies, minimum 

PV values for "high-quality" seed lots can be sug-- 

gested: eastern white pine - 3.0; shertleaf pine - 3.5; longleaf pine - 4.0; and Virginia pine - 5.0. 

These values assume renoval of empty seeds 5y proper seed cleaning, and they may difIer slightly under different test conditions, Uhen test results 

show PV'S above these Levels, normal stratiiication 

periods should be used: Tirginia pine - 14 days; 

shortlea: pine - 14 to 28 days; and eastern white 

pine - 30 to 60 days, Longleaf pine should not be 

stratified. If fV7s are below the suggested values, 

stratification periods should be shortened by about 

one-third to avoid damage to the seeds. 

Since more vigorous seeds will germinate better at low temperatures than weak seeds, seed Lots 

with the higher P7's should be sown iirst when soil 

temperatures are usually lower. Less vigorous lcts 

(PV below the minimum) should do better when soil 

tem~eratures are higher. The best utilization of 

seeds, however, will result from the nursery manager knowing how each of the seed sources react to 

stratiiication and conditions oL' the nursery. Xith 

the current practice of repeatedly sowing with the 

same 2amilies or seed sources from the same orchards 

year after year, there is no reason why this inzormation should not be available. 

Interpretation oi leachate conductivity data 

is not well-defined at this time. 30th mean conductivity and estimates by the :IS method have been 

reliable in certain situations, ZIowever, seed conditions can inlluence the conduc tivity/vigor relationship in many cases (Vozzo l9C4; Vozzo and Bonner 

19C6), and additional research must be done to develop this promising technique. :lost seed managers 

would sacrifice a certain amount of accuracy to get 

an estimate of quality in 24 hours as compared to 

the 30 or 50 days of a germination test. 

CONCLUS 13145 

LITEIATURE CITES 

Association of GfZicial Seed Analysts. ?<ules for 

testing seeds. Journal oE Seed Technology. 3(3) : 

1-126; 2 978. 

Earnett, 2'. ?,; Ilclenorc, 13. Y. Sermination speed 

as a predictor of nursery seedling performance. 

Southern Journal of Applied Zorestry. C:151-152; 

1986. 

Bonner, 7. T. ::easurement oi seed vigor :or loblolly and slash pines. Forest Science. 32:170- 

1:e; r986. 

Banner, F. T.; Vozzo, J. A. Evaluation of tree seeds 

by electrical conductivity of their leachate. 

Journal o: Seed Technology. 10: 142-150; 1986, 

Eoyer, J. N.; South, D. B.; Xuller, C. [and others] 

Speed oZ gernina tion affects diameter at lifting 

of nursery-grown loblolly pine seedlings. Souther 

Journal of Applied Forestry. 9: 243-247; 1385. 

Czabator, F. J. Germination value: an index combining speed and completeness of pine seed germination. Forest Science. C:386-336; 1962. 

Ploore, R. P. Tetrazolium evaluation of tree and sl~rul 

seeds. 16th ISTA Congress. Preprint No. 69.; 1971. 

7 P* 

Vozzo, J. A, Evaluating seed leachzte measurement 

relative to imbibition time and solute volume. 

Journal of Seed Technology. 9: 54-59; 1984. 

Vozzo, J. A.; Bonner, S. T. Ssing electrical conductivity o; seed leachate as a measure of seed 

quality in southern pines. In: South, D.3., ed. 

Proceed ings, international symposium on nursery 

management practices :or the southern pines; 1985 

Aug. 4-9; l:ontgonery, AL. Auburn, AL: Alabama 

Agricultural Experiment Station and International 

3nion Forestry Research Organization; 1985. 594 2. 

;!asser, R. G. Tree improvement resezrch. In: Lantz, 

C.IJ., Comp. ?roceedings, 1978 southern forest nursery cenCerences. Atlanta, GA: U.S. Department 

oL Agriculture, Forest Service, State and Frivate 

Forestry; 1979. 170 p. 

Laboratory germination tests and seed Leachate 

conductivity measurements can be used to evaluate 

seed vigor in longleaf, shor tleai, Virginia, and 

eastern white pines. Total germination and ?V, a 

measure oZ' germination rate, are 2rcTerred pararneters 01 germination tests. Electrical conductivity 

measurment shows great promise as a rapid estimate 

02 vigor. 
THE EFFECT OF SEED TREAfMENT AND SOWING METHOD 

ON GERMINATION OF OCALA SAND PINE 1' 

21 Kenneth W. Outcalt - 

Abstract.-- Ocala sand pine (Pinus clausa var. clausa b. 6. Ward) 

seeds, ha1 f of them presoaked and ha1 f untreated. were sown in a sreenhouse-study in fine sand soil at moisture contents (by weight) of"2, 5, 

and 10 percent by pressing into the soil, by broadcasting and covering 

with soil, or by broadcasting and covering with soil which was packed. 

In a second test presoaked and control seeds were sown in soil at 3, 5, 

and 7 percent moisture by pressing into the soil . Soil at 2 percent 

moisture content was too dry for any gemination even if seeds were 

presoaked. The seeding method had no effect on speed of gemination or 

total gemination. Presoaking seeds resulted in more rapid gemination 

in both tests and at the 5 percent soil moisture content an increase in 

total gemination of about 20 percent in the first test. Most of the 

time soil moisture will be between wilting point, about 2 percent, and 

fie1 d capacity, about 10 percent, Thus, presoaking may be a way to 

i ncrease seed gemination. In addition presoaki ng coul d reduce 1 osses 

to predation by speeding up gemination. A1 though presoaking appears 

beneficial and did not have any negative effects on viabil ity of seeds 

lying in dry soil, field tests are needed before a final evaluation can 

be made. 

INTRODUCTION 

Ocala sand pine (Pinus clausa var. clausa D.B, 

Ward) is native to the droughty, acid, infertile, 

marine deposited sandhills of Florida. The largest 

concentration occurs in the center of the state on an 

area known as the Central Highlands. The understory is 

primarily evergreen shrubs 6 to 10 feet tall with very 

1 i ttl e herbaceous ground cover (Laessl e 1958)- Typical 

and of clay colloids, cation exchange capacities and 

moisture retention of these soils are low (Burns and 

Hebb 1972). Due to the soil ' s low moisture-holding 

capacity, drought conditions can exist within 2 weeks 

of a heavy rai nfal 1 . A1 so surface temperatures of exposed soils may reach 140" F on sumner days, which is 

why these areas have been called deserts in the rain 

(Burns and Hebb 1972). 

understory species are sand 1 i Ocala sand pine begins cone production at an early 

anavar eminata (Small) Sarg.), 

mia W~I* 

age, about 5 years, and has abundant annual crops (BarChapnan oak (Q. nett and McLemore 1965). The cones are predminately 

palmetto (Sabal spp.). This area has, hot, hunid sum- serotinous and persist on the tree for many years. 

mers, somewhat dry winters, and a long growing season Most natural stand have originated from seed released 

of 269 to 312 days. Precipitation is abundant, 53 to 

60 inches per year, and is fairly we1 1 distributed 

(Burns and Hebb 1972). 

Sandhills soils are acid, infertile and droughty 

jnarine deposits from the interglacial stages of the 

Pleistocene epoch. Ekcause of sorting action during 

deposition, they are largely quartz sands, ranging from 

a few feet to more than 20 feet deep. Organic matter 

content is low because the climate prmtes rapid oxidation. Because of the low levels of organic matter 

1' Paper presented at Southern Si 1 vicul tural Research Conferrence, At1 anta, Georgia, November 4-6, 

1986. 

Soi 1 Scienti st, USDA Forest Service, Southeastern Forest Experiment Station, 01 ustee, FL 32072. 

by the serot i nous cones fol Towing wi 1 dfl' res. Attempts 

have been made to get natural regeneration by using the 

heat from the sun to open cones in 1 oggi ng slash, but 

stocking has been be1 ow acceptable level s (Price 1973). 

Burning 1 ogging slash to release seeds has a1 so been 

tried, but it gave poor results because available cones 

were unevenly distributed and the fire destroyed ~nany 

seeds (Cooper et al., 1959). 

Ocala sand pine can be planted, but due to its 

lack of true winter-type domancy (Zelawski and Strickland 1973), survival is generally poor, about 60 percent, and variable (Burns and Hebb 1972, Hebb and Burns 

1973). The most successful and econmicaf system for 

regenerati on has been cl earcutt i ng, site preparation, 

and direct seeding (Price 1973). Seed is broadcast at 

a rate of 0.5 to 1.0 pound per acre foll owing site 

preparation by double chopping with a heavy, duplex 

brush cutter. Research and experience has shown that 
some method of covering the seed with a 1 ayer of soi 1 

0.25 to 0.75 inches thick will reduce seed predation 

and increase gemination (Burns and Hebb 1972). 

Although broadcast seeding has been the most successful system for regeneration of Ocala Sand Pine it 

has not been enti rely satisfactory. Many areas, especial ly during years with extended drought periods, 

which occur about 3 years out of 10, fail to regenerate 

adequately. In addition many areas are overstocked and 

require precmerci a1 thinning to prevent stand stagnation. In an attempt to improve spacing, eliminate 

precmercial thinning, and reduce costs, a new system 

using a bracke scari f i er-seeder was recently empl oyed. 

This systm was very successful the first year, but 

since then a1 most a1 1 of the areas seeded with it have 

failed, as have the majority of the areas that were 

broadcast seeded. If the success ratio could be improved by even a smal 1 margin it would result in considerable savings. Two areas where gains might 

possibly be made are improving the seeding method or 

pretreat i ng the seed. 

The specific purpose of this study was to determine 

if packing the soil over the seed or presoaking the 

seeds in water would increase germination and if there 

were any interactions between packing , soi 1 moisture 

content, presoaking and geminati on, 

METHODS 

A smpl e of the Ocal a sand pine seed fran four di fferent seed lots being used for regeneration during the 

1985-86 season was obtained from personnel on the Ocala 

National Forest. A1 1 seeds were from cones colt ected 

on the Ocala National Forest and processed by the Nati onal Tree Seed Laboratory, Processi ng i ncl uded extraction, cieaning, and coating with Arasan and 

Aluminum powder. Prior to study initiation seeds were 

tested for viability on gemination paper in boxes at 

the Olustee Laboratory, Florida, Because a1 1 lots had 

similar and high viabil ities of about 80 percent, a17 

tests were done using a mixture of seeds fran all lots. 

A spl it-plot factorial design was used in both portions of the study. All gemination tests were done in 

6.75 x 4.75 x 2.25 inch gemination boxes under greenhouse conditions at the 01 ustee Laboratory. Control 

seeds were planted in half of each gemination box and 

presoaked seeds in the other ha1 f. Presoaking was done 

in tap water at 38" F for 24 hours. Upon removal from 

cold storage the water was drained from soaked seeds 

and they were blotted dry enough with towels so they 

would not stick together and then planted. In the 

first test, soil fran the E horizon of a B1 anton fine 

sand (1 oamy , sil iceous , themic grossarenic paleudul t ) 

with mi sture content by wight of 2, 5, or 10 percent 

was used in factorial canbinations with seed planted 

three ways: by pressing into the soil ; broadcasting and 

covering with soi 1; or broadcasting and covering with 

soil which was then packed, these moisture levels were 

chosen to represent effective wilting point, minimally 

adequate, and field capacity and the methods were to 

simulate dri 11 ing in seeds, the present systm of sowing, and present system with the addition of a packing 

wheels, respectively, In the second test the surface A 

and E horizons from a Paol a sand (hyperthemic, uncoated spodic quartzipsment) soil at moisture contents of 

3, 5, and 7 percent with three rep1 ications was used 

and a1 1 seeds were planted by pressing into the soil . 

The number of seedlings merging from the soil was 

counted in each box at weekly intervals for three weeks 

follwing sowing. At the end of the initial three 

weeks in the second study, enough moisture was added tct 

the boxes that originally had 3 percent water to bring 

them to 10 percent and these were monitored for an addi tionaf three weeks. Percent gemination data were 

analyzed by analysis of variance for each test by individual week, 

RESULTS AND DISCUSS ION 

There was not enough moisture available at the 2 

percent level for any gemination to occur. This was 

expected since this moisture 1 evel was included to represent soil at the effective wilting point. Gemination was also very 1 imited (about 3 percent) at the 3 

percent soil moisture level. The sowing method used 

had no effect on total gemination which was 79, 77, 

and 74 percent for broadcast, cover and pack; drill; 

and broadcast and cover, respectively. As could be 

expected, total germinati on increased with percent soi 1 

moisture (Table 1 and 2). Presoaking seeds significant 1 y i ncreased the speed of genni nation, especi a1 1 y 

in the first test. The increased speed of germination 

may be due to the higher moisture level of presoaked 

seeds, 22 versus 8 percent for normal seeds, since it 

is quite 1 ikely seed must reach a critical moisture 

1 evel before certain physi 01 ogi cal processes necessary 

for gemination can begin. However, presoaking may 

just increase the abil ity of the seeds to imbibe water, 

since Barnett and klemore (2965) found soaking sand 

pine seeds in 95 percent ethanol a1 so increased the 

speed of gemination. In the first test presoaking 

a1 so increased total gemination at the 5 percent soi 1 

moisture level (Table I), It may be that with 1 imited 

moisture the presoaking allows a few more of the seeds 

to reach the critical level. The results of the second 

test, however, were contradictory as total gemination 

was not effected at any soil moisture level by presoaking (Table 2). This may be due to the lower overall 

germination rate of this test, 

Table I.-- Effect of presoaking on gemination of Ocal a 

sand pine seed at soil moisture contents of 5 and 10 

percent. 

Days Treatment Germination at soi 1 moisture level 1 

after 5-percent 18-percent mean I 

sowing j i 

Percent 

6 Presoaked 2 5 2 3 1 / 24a- I 

Control - 7 - 3 - 5b 

Mean 16 1 3a 

12 Presoaked 7 1 7 6 73c 

Control - 37 - 5 3 45d 

Mean 54c 65c 

21 Presoaked 7 9 $5 82e 

Cont ro 1 - 56 - 85 71e 

Mean 68f 85e 

L' Means within a row or a colmn for each data not 

followed by the same 1 etter are significantly different 

at the .85 level. 
Table 2, --Effect of presoaking on gemination of Ocal a 

sand pine seed at soil moisture contents of 5 and 7 

percent. 

Days Treatment Gemination at soil moisture level 

after 5-percent 7-percent mean 

sowi na 

LITERATURE CITED 

Barnett, J. P,, and B, F. Mctmore, 1965. Cone and 

seed characteristics of sand pine. USDA For, 

Serv, Res, Pap, 50-19, 13p. South, For. Exp. 

Stn, , New Or1 eans , LA, 

Percent 

7 Presoaked 18 29- 24J-/ 

Burns, R,M., and E.A. &bb. 1972. Site preparation and 

reforestation of droughty, acid sands. USDA For, 

Serv. Agric. Handb. 426, 61p. 

Control - 8 - 15 

Mean 13a 22b 

14 Presoaked 25 58 42c 

Cont ro1 - 25 - 42 34c 

Mean 25c 50d 

2 1 Presoaked 25 61 43c 

Control - 25 - 49 37 c 

Mean 25c 55d 

Means within a row or a colunn for each data not 

followed by the same letter are significantly different at the .05 1 eve1 . 

Seed losses to predators can and often are a substanti a1 probl em i n arti fi ci a1 regeneration of Ocal a 

sand pine stands by direct seeding. Cooper et a1 . (1959) concluded that the loss of seed to rodents, 

birds, and ants was the single 1 argest obstacle to the 

successful regeneration of Ocal a sand pine by artificial seeding, Presoaking Ocala sand pine seed before 

sowing seems to be a simple way to speed up the rate of 

germination. This would be advantageous under field 

conditions since the sooner the seed geminates and 

begins growth the less time it is exposed to the dangers of predation, In addition this study indicates 

that under sme conditions presoaking may a1 so increase 

total germination, 

One of the possible disadvantages of presoaking 

seeds could be the 1 oss of viabil ity if sown in very 

dry soi 1 s. Thi s cou1 d occur i f presoaking caused seeds 

to begin gemination at soil moisture levels that were 

too low for successful cmpl etion of seedl ing emergence 

or if presoaking changed the physiological state of the 

seed such that it was more susceptible to damage while 

lying in the soil waiting for precipitation to raise 

the soil moisture level enough for gemination to occur. In this study, if moisture levels were too low, 

seeds did not begin gemination even if presoaked and 

there was no evidence that presoaking seeds reduced 

their viability while lying in soil at lw moisture 

levels. When water was added to soil after 3 weeks of 

simulated drought conditions both presoaked and control 

seeds had an equal gemination rate, about 53 percent. 

This was essentially equal to the 55 percent rate for 

seeds sown in soil which initially had adequate moisture for geminat ion. 

Cooper, R,W., C.S. Schomyer, and W.H.D. McGregor, 

1959. Sand pine regeneration on the Ocal a 

National Forest. USDA For. Serv. Prod, Res. Rep. 

No. 30. 37p. 

Hebb, E.A,, and R.M. Burns. 1973. Methods ~nd goals in 

preparing sand pine sites. In: Proc. Sand Pine 

Symp. , Dec, 5-7, Panama Ci tyTeach, FL. USDA For, 

Serv. Gen. Tech. Rep. SE-2. Pp.82-92. 

Laessle, A. M. 1958. The origin and successional relati onshi ps of sandhi 1 1 vegetation and sand-pi ne 

scrub. Ecol . Monogr, 28: 361-387. 

Price, M. B. 1973. Management of natural stands of 

Ocal a Sand Pine. In: Proc. Sand Pine Symp. , Dec. 

5-7, Panama City ~Gch, FL. USDA For. Serv. Gen. 

Tech. Rep. SE-2, pp.144-152. 

Zel awski , W. and R. K. Strickl and. 1973. Temperature 

effects on growth, assimilation, and bud development of sand pine. In: Proc. Sand Pine Symp,, Dec. 

5-7, Panama City Beach, FL. USDA For. Serv, Gen. 

Tech. Rep. SE-2, pp.73-81. 

A1 though presoaking Ocala sand pine seeds appears 

prani sing it should be tested under fief d conditions 

before it is adopted for general use, This will be 

done very soon by using presoaked seed in one seed box 

and control seed in the other of a two row bracke 

seeder on sane operational seeding jobs on the Ocala 

National Forest. 
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injury and disease, and were obsemcsd to have 

nunerous cones present. Residual trees were well 

distributd across each plot for good seed 

cover&Te 1-&en dis~rsal occurs. Residwl stand 

conditions are described in table 1. 

The study began in spring 1982 when five 

replieations of' six treataents laid out in a 

randonized bloc;: experl3ental design. Individual 

pemaent 2.0-acre rectangular plots for each 

treatnent were installed on each block. The 

followin3 treatnents were assigned to the plots: 

Prior to harvest, a SLUI"]E~~ burn %as conducted on 

one-half the treatments. This portion of the 

treatsent was accoapiishd by strip headfires that 

consuned the undemtory vegetation but did not 

damage the overstory, The duff layer was reduced 

to less than I-inch throughout the areas burned 

and served to improve, the seedbed siqnif icantly. 

The burnin2 was tined so "chat it occurrd prior to 

seedfall. 

1. Clearcut with seed in place and no 

preharvest burn. This serves as the 

control. 

2. Clearcut with seed in place, with preharvest 

burn. 

3. Seed tree cut with 8 to 10 seed trees per 

acre after harvest and no preharvest burn. 

4. Seed tree as in treatnent 3, t~ith preharvest 

burn. 

5. Sheltert-rood cut that redttces stand to 25 

square feet of basal area per acre and no 

preharvest burn. The renoval cut is 

scheduled 5 years after harvest. 

6. Sheltertrood cut as in treatcent 5, with 

preharvest burn. 

The harvest out was nade in the spring of 1963 

with a total of 823 !:1 fbx of pine logs and 355 13 

fbm of pine round+$ood removed fron the 100-%re 

study area. Care was taken to ensure that no 

danilge occurred to the selelcted seed trees in the 

harvesting process. During the sunxir of 1983, 

all hardwod stems I-inch d.b.h. or larger on all 

of' the 2-acre treataent plots were i-njectd with 

Tordon 101, . After the 2-acre square plots i?ere delineated on 

the ground, a complete inventory was :lade of all 

nerchantable trees on each plot. With these data 

in hand, residual trees were selected for all but 

the elearcut plots. Trees selected as seed trees 

were strai~ht, had sod forn, ;.?ere free fron 

After harvest, four permanent nilaere sanple 

plots :rere installed on each trea"cmn"c plot for 

the purpose of deter..?inj.n~ the nuaber of pine 

seedlings established at 1, 2, and 3 years after 

harvest. 

Table 1 ,--Residual plot inventory data, by treat~~ent, 1982 

Preharvest Seed trees T 5e an Basal area liean 

!3loc!c Plot Treatrlent burn per treat~llcnt d .b.h. /ac~e ht. 

- No. Inches l?tL Feet 

Clearcut 

Cleareut 

Shelter~~ood 

SI?eltem.rocswjl 

Seed Tree 

Seed Tree 

Glaarcut 

Clearcut 

Shelt e mrood 

Shel kerr:ood 

Seed tree 

Seed tree 

Seed tree 

Sew$ trce 

S;lelter:~ood 

She1 tenioocl 

Clearcut 

Clearcul; 

Sheitexzrood 

She1 te~~ood 

Cltesrcut 

Clearcut 

Seed tree 

Seed tree 

Seed tree 

Seed tree 

Shelter-.,:ooti' 

Shel ternrood 

Clearcut 

Cleareut 

Yes 

So 

Yes 

IJo 

Vo 

Yes 

30 

Yes 

Yes 

!To 

Yes 

lio 

170 

Yes 

I'o 

Yes 

Yes 

T";o 

110 

Yes 

/To 

Y 2s 

110 

Yes 

Yes 

I10 

Yes 

IT0 

?Jo 

U2s 
fit 1 year ~fter :;arT~i;st, tke :lu:-xr of 3eedlinc;s 

esteblished per acre rrznyed Pro3 2CC ner acre on 

the seed tree and burn treatxent u? to 650 per 

acre on the s:?elter::ood treatr?cnt (table 2). 

Anal;rsis of variance letera~iured that stoc::in-; 

axon2 "ceatzents was not si:nii"icactly dii":crent. 

Iforaever, in terrl of adequate stoc::in:, it appears 

that this firs5 year did not represcat a ,!ooc! seed 

production yee-. Based on inforna,lon froa 

Geor-;ia %restr:r Cor;lr?islion Seed Oi-.charrds, 1983 

bras a qoor year for seed-?rocfu.ction, -$hereas 19811 

and 13% rere ~od seed producin? years (Terrell 

Brool:~, pers. co.mTun., June 10, 1986). 

Table 2.--!lean nu:lber or pine seedlings 3er acre 

for each of 3 yzars after harvlst, by 

treil"ci?ent 

Clearcut 400a 1,950~ 1,250b 

Clearcut and burn 400 a 3,100 e 2,550 b 

Sneltemood and burn 550 a 9,35Q a 19,900 a 

Seed tree 550 a 4,300 bc 3,900 b 

Seed tree and burn 200 a 6,950 a2 5,000 b 

:leans fol.lo.rred by "Lie sarze letter are not si~r?ificanli.ly different at the 0.05 level. 

It is, of course, illo~ical to assune ::hat 

survival will be 100 gereent, due to either 

prolon.;ed periods of drou~ht or da-?aye caused by 

cuttin-; ale; rexovin.; the seed trees frail the 

plots. In fact, the beat conclusion is that 

additional seed are needed on all plots in order 

to attain an adequate stoclciny. This is no 

problen and denonstrates one of the advant~yes of 

reseneration by naturel mans beczuse the seed 

source is still present and has the potential to 

supply another seed crop. 

At 2 years after harvest, thc additional seed 

crop is evident by j.,~creases in the nu rber of 

seedlinrjs present on all treat:;cnt plots (tsjle 

2). The sheltert~od and burn treatnent plots had 

the most seedlinys per acre and increased by 5,800 

seedlinqs per acre over the previous pear. Plots 

trith clearcut only treatilen-ad 1,850 scedlin~s 

per acre and increased by 1,250 seedlings ?er acre 

over tile precedi??,~ year*. T11ese seed are presuxed 

to have cone in fro^: the adjacent plots, since 

advance re,;eneration is essentially ruled out at 

this tine. Yo:rever, the clearcut treatnent does 

possess tke potential to produce an adequately 

stoc!:ed stand if one-tktircl of t"l seeedlin~s are 

able to survive. All other treat7:ants sho:r 

excellent potential for produein? adequately 

stoc:ced stznds at this ti=. It also appears that 

it is possible, aft;er t::o seed crops, for the seed 

trees to be re~oved. rlma?e incurre3 by this 

re~oval would sene to reduce the nunber of 

seed1in:s zreatly. 

It i:; of interc;sl; to note that at 2 years after 

harvest, all treak~ent ?lots ttha", irere preseribecl 

burned had ,lore seedlin-;s per acre tinan t'lose 

without the Ssrn. fibis ii?d?cates that the seedbed 

is 2ore receptive after eonpetin2 vesetation is 

rdueed alon:: !lit% the litter depth (?render 

1373). 

At 3 years after harvest, the shelterrrood and 

burn treatr3ent is the only one that achieved a 

continued iacrease in nu?oer of seedlinqs ?er 

acre. T:le larq;ezt decrease rras frob- the elea?eut 

treat~ent, vitl? a 13 percent decease in ?~wlber of 

seedliny per acre. These elcarcut plots continue 

to sup?ly t!~e feriest nu-13er of se&lir~gs per acre, 

but they still have 9otential Lo aehie-~e r%ll 

st06::iny if 7i~rtality does not e:c-ce& 50 percent 

of the ?resent density. All the other treatxnt 

rnethodr; appear to have the po"ce?tiaf. to achjsve 

full stoclriny. Tt is a.-itxeipated t1:at the lenzthy 

Crour;ht of the past sv,-lrEr (1036) as :?ell as %he 

dan::4ty reduction th~t Pol1o:rs the seed tree 

rez~oval will Gene to thin tke seedlin7s on the 

plo",. It is also notefr~rthy "chat 3 years af'ter 

harvest, t:ne plots that \:ere ,rescribed burned 

still 3avc -lore scedlinys 2er acre thalz those that 

rrere not burned. 

At 3 years after !~arver;k, this stx,y s;?ot:s that 

al-1 treat ~enb are succe3sfful and hava potential 

to establish en adequately stocoed stsnd. The 

stand .:ill continue to need 5anrr;exent in order to 

insure F)ropCin spacinr; an2 the best stoc!cin~i; for 

the site. Th@ replo7~nl of the seed trees should be 

planned for best benefit to each treatxent ?lot 

and to ingrove the Lon7 tern value of the stand. 

The study is also considered to be successful in 

that it serves to bcncfit the noni:ldustriel 

private forest (IiLT ) landormer audience for which 

it !;as desF.~ned and establish& by bein? utilized 

as a dezanstration site. 

Brencler, ?rnst Y, Silviculture of loblolly pine 

in tke Ck?or$.n pied-lont. Ga. Po?, Fes. Counc, 

gep. 33, :lacon, GA: Geor5ia brrestrgr Coxr1i3sion; 

1973. 7Q PP. 

Taiisey, John 3. Forest statistics For Georzie, 

1382. 8esour. "uLI. SR-Sa. Ashevilie, :TC: 

U.S. Departnent of Ayriculture, Forest Service, 

Southeastern Forest Ex?erine:lt Stat ion; 1983. 
Prescribed Fire 

Moderator: 

Walter A. Hough 

Southern Forest Experiment Station 

REGENERATION OF HARDWOOD COPPICE FOLLOWING I 

CLEARCUTTING WITH AND WITHOUT PRESCRIBED FIRE 

M. K. Augspurger, D. H. Van Lear, S. K. Cox, and D. R. Phillips 2 

ABSTRACT.--Three hardwood stands in the Piedmont and Southern Appalachians of South Carolina and Georgia were clearfelled in the winter of 

1982-83. Following harvest, designated study plots were broadcast 

burned during the fall of 1983. Hardwood coppice regrowth was measured 

one and two years after burning. Burning significantly increased the 

total number of basal sprouts for the oak and miscellaneous species 

group. Poor drying conditions on north-facing slopes resulted in low 

intensity fires with less effect on sprout origin. Two years following 

treatment, the number of small stumps (<5 cm) having at least one 

living basal sprout were greatest on burned plots. Broadcast burning 

favorably influenced hardwood coppice regrowth by promoting basal 

sprouting and by encouraging sprouting from small stumps. 

INTRODUCTION METHODS 

There are approximately 5.5 million acres of 

upland hardwoods in the mountain and Piedmont 

regions of South Carolina and Georgia (Bechtold and 

Phillips 1983; Tansey 1983). In many instances, 

these stands have undergone multiple highgrades, 

leaving them understocked with low quality or 

undesirable species. These past harvesting 

practices result in stands that are, in many cases, 

not indicative of the site's capability. 

Broadcast burning is increasingly used as a site 

preparation tool on U.S. Forest Service lands 

following harvest of these low quality stands. 

The expense incurred by burning is considerably 

less than costs associated with other site preparation techniques (Moak et al. 1983). However, few 

studies have evaluated the silvicultural advantages 

of burning logging debris on hardwood coppice in 

the Southern Appalachians and Upper Piedmont. With 

the cooperation of the U.S. Forest Service, a study 

was initiated in 1982 to determine effects of 

broadcast burning of logging slash on hardwood 

coppice regrowth. Specific objectives of this 

study were: 

1. To determine effects of burning on the number 

and origin of hardwood sprouts. 

2. To determine the influence of aspect on 

burning effectiveness. 

Study Areas 

Study sites were located in three areas where 

clearcuts in mixed hardwood stands were planned: 

(1) Clemson University Experimental Forest, Oconee 

County, South Carolina; (2) Chattahoochee National 

Forest, Habersham County, Georgia; and (3) Sumter 

National Forest, Oconee County, South Carolina. 

Xeric (south) and mesic (north) aspects with 

similar slope, soil and species composition were 

selected on each of the three areas. Prior to 

harvest, predominant species at all locations were 

scarlet oak (Quercus coccinea Muenchh.), southern 

red oak (9. falcata Michx.), white oak (9. alba 

L.), chestnut oak (9. prinus L.), pignut hickory 

(Carya glabra Mill.), red maple (Acer rubrum L.) , sourwood (Oxydendrum arboreum L.), black cherry 

(Prunus serotina Marsh.), blackgum (Nyssa 

sylvatica Marsh.), and dogwood (Cornus florida 

Slopes ranged from 40 percent on the Clemson 

site to 60 percent on the Georgia site. Soils on 

the Piedmont site were clayey in texture while 

mountain soils were loamy. All soils developed 

largely from gneiss and schist parent materials 

and are classified as Typic Hapludults. Elevation 

at the Clemson location, a Piedmont site, averaged 

800 ft while elevations at the Sumter and Georgia 

locations in the Southern Appalachian mountains 

were 1500 and 2500 ft, respectively. 

3. To evaluate effects of stump size on sprout 

production following burning. 

Sampling Procedures 

During the fall of 1982, six 0.12 ac rectangular 

'paper presented at the 4th Biennial Southern plots were established on both mesic and xeric 

Silvicultural Research Conference, Atlanta, aspects at each of the three study areas. Prior 

Georgia, November 4-6, 1986. to harvest, seedlings and root-suckers <4.5 ft 

tall were tallied on four 1 m wide transects 

'~esearch Forester, Professor, and Research equally spaced along the contour of each plot. 

Forester, Department of Forestry, Clemson Univer- Saplings >4.5 ft, but less than 4.5 in DBH, were 

sity, Clemson, South Carolina; and Principal tallied between alternate transects by species, 

Mensurationist, Southeastern Forest Experiment DBH, and total height. Trees (>4,5 in DBH) were 

Station, U.S. Forest Service, respectively. tallied in a 100 percent inventory. 
Harvest of merchantable products frorn the Clernson 

and Sumter sites occurred between October 1982 and 

brch 1983. Residual trees were chainsaw felled in 

July 1983. Limited access, steep topography, and 

lack of markets prevented removal of otherwise 

merchmtable material frorn the Georgia site. All 

stems were clearfelled on this site and left in 

place. 

Three plots on each aspect were burned in October 

1983 on all areas. Relative humidities during 

burning ranged from 30-50 percent, winds averaged 

5 mph with occasional gusts, temperatures were in 

the low 80'5, and the last significant rain on the 

areas occurred 7-12 days prior to the burn. 

Burning was planned for late summer but was delayed 

because of weather and logistical problems. 

The burning technique used was similar for all 

areas. Back fires were set at the top of the 

slopes and at the downwind flanks on both north 

and south aspects. After the back fires had moved 

downslope a short distance, strip head fires were 

ignited in succession at 20-30 ft intervals across 

the slope until the areas were completely burned. 

Fuel consisted of hardwood tops, hardwood 

litter, and green herbaceous material. The fire 

was primarily carried by cured leaves on felled 

hardwood tops, Hardwood litter was fairly 

continuous on all three areas- Although green 

herbaceous material was moderately distributed on 

all areas, poor drying conditions prevented it 

from being a major fuel component on the northern 

aspects, 

White pine seedlings (2-0) were planted during 

the winter following the burn, which was 

prescribed to improve plantability of the site. 

Large quantities of logging debris in the absence 

of burning make hand planting nearly impossible. 

Because of the slow early growth of white pine 

seedlings, results of this phase of the experiment 

will be reported later. 

Numbers of hardwood seedlings and saplings were 

inventoried 1 and 2 yr after burning. Sampling 

methods used were the same as pretreatment 

inventory methods, Trees and saplings which had 

been cut during the harvest or clearfelling 

operations were inventoried on four 305 ft2 sample 

plpts located in each corner of a11 treatment 

plots. Sprouts from cut stumps were grouped into 

classes based on origin, Stool sprouts originated 

from adventitous buds at the cut surface perimeter 

of the stump. Sprouts from dormant buds located 

below the cut surface and above the ground line 

were designated as epicormic sprouts, while basal 

sprouts originated at or below the ground line. 

Coppice sprout data were collected one and two 

growing seasons after the burn. 

Data were statistically analyzed as a split plot 

design, with aspect designated as the major 

treatment. Burning was considered the minor 

treatment and was assigned at random to subplots 

within each major plot. Locations were considered 

replications, All treatment differences were 

tested at the 5 percent level of significance. 

RESULTS Ah3 DISCUSS103 

One year after treatment coppice sprouts totaled 

104,958 and 78,755 stenslac on the burned and 

unburned plots, respectively (Table 1). Oaks 

comprised 23 percent of the total number of stump 

sprouts on both burned and unburned plots. Seedlings and seedling sprouts were not as numerous. 

Oaks accounted for 32 and 16 percent of the total 

number of seedlings and seedling sprouts on the 

burned and unburned plats, respectively. 'Cv'hile it 

is doubtful that these densjties are needed to 

successfully regenerate the stand, recent symposia 

and bibliographies have documented the beneficial 

effects of increased sprouting following burning 

on wildlife habitat (Harlow and Van Lear 1981, 

Wood 1980). 

Table 1.--Number of Stump Sprouts, Seedlings or 

Seedling Sprouts (Per Acre) by Species Group One 

and Two Years Following Burning. Data Shown Are 

Combined for All Locations. 

' STUMP SPROUTS 

Year 1 Year 2 

Burned Unburned Burned Unburned 

Oaks 27,851 14,176 23,626 9,092 

Misc.spp. 77,108 64,579 66,368 55,306 

Total 104,959 78,755 89,994 64,398 

SEEDLINGS OR SEEDLING SPROUTS 

Year 1 Year 2 

Burned Unburned Burned Unburned 

Oaks 13,673 7,515 14,361 13,605 

Misc. spp. 29,183 40,638 40,537 51,173 

Total 42,856 48,153 54,898 64,778 

Since burning killed one-year-old sprouts, age 

of regrowth differed between burned and unburned 

plots, One year after treatment, sprouts on 

burned plots would be one year old while sprouts 

on unburned plots would be two years old. This 

unavoidable age difference undoubtedly influenced 

sprout density on burned and unburned plots at 

time of sampling. However, the influence of age 

is considered minor in relation to the effect of 

burning. 

The rate of mortality was related to sprout 

origin. Two years after treatment, basal sprouts 

on burned plots had declined 12 percent, while 

sprouts originating higher on the stump had 

declined 41 percent (Table 2). Early studies 

(Roth and Sleeth 1939, Keetch 1944) indicated that 

burning improves sprout origin. They suggested 

that, by promoting sprouting lower on the stump, 

the incidence of decay in sprouts would be less on 

burned areas. Smith ( 1969) and Watt (1979) 

reported that the incidence of decay is less on 

sprouts originating close to the ground, probably 
because such wounds are more readily compartmentalized by callus tissue formation (Jensen 1969, 

Shigo 1979). 

Table 2.--Number of Sprouts (Per Acre) by Origin 

One and Two Years Following Burning. Data Shown 

Are Combined for All Locations. 

OAK SPECIES 

Year 1 Year 2 

Burned Unburned Burned Unburned 

Sprout origin 

Basal 26,920 10,023 23,304 8,663 

Epicormic 895 4,081 179 322 

stool -- 3 6 7 2 - 14 3 107 

Total 27,851 14,176 23,626 9,092 

OTHER SPECIES 

Year 1 Year 2 

Burned Unburned Burned Unburned 

Sprout origin 

Basal 67,836 41,740 60,354 41,310 

Epicormic 9,093 20,512 5,692 12,815 

stool 

Total 

Fire promoted sprout formation lower on the 

stump. One year after burning, 97 percent of all 

oak sprouts from cut stumps were classified as 

basal sprouts, whereas only 71 percent were basal 

sprouts on unburned plots. Similar results were 

noted on the miscellaneous species group. 

The number of epicormic sprouts, an undesirable 

type of sprout, in the miscellaneous group was 

less on burned plots one and two years after 

treatment. The number of epicormic sprouts on 

burned plots was only 56 percent of that on 

unburned plots. Although numbers of epicormic 

sprouts on oak stumps tended to be higher on 

unburned plots, differences were not significant 

because of variability among plots. 

Auxin translocation by epicormic sprouts 

probably limits numbers of basal sprouts by 

inhibition of suppressed buds at or below the root 

collar. Our data suggest that numbers of basal 

sprouts on unburned plots for both oak and 

miscellaneous species were reduced by higher 

numbers of epicormic sprouts (Table 2). Basal 

sprouts for the miscellaneous species group were 

significantly greater on burned plots one and two 

years following treatment, while oak basal sprouts 

were significantly greater on burned plots two 

years following treatment. Waldrop et al. (1985) 

also noted increased sprouting of hardwood stumps 

following broadcast burning in eastern Tennessee, 

while Danielovich et al. (1987) reported increased 

sprouting in the mountains of South Carolina after 

broadcast burning. 

Although fire increased basal sprouting of oaks 

on both northerly and southerly aspects, greatest 

increases occurred on southern aspects (Table 3). 

Poor drying conditions under clumps of mountain 

laurel (Kalmka latifolia L.) and the more shaded 

exposure resulted in spotty, low intensity fires on 

northern aspects. As a result, many regrowth stems 

were not top-killed. In contrast, southern slopes 

burned more intensely with greater top-kill and 

resprouting. Burned plots on southern aspects had 

about 3.5 times as many basal sprouts as unburned 

plots one and two years following burning. As 

opposed to the fall burning conducted in this 

study, current Forest Service practice is to burn 

clearcut sites in the summer when better drying 

conditions prevail on both southern and northern 

aspects. 

Table 3.--Number of Oak Basal Sprouts (Per Acre) 

by Aspect One and Two Years Following Burning. 

Data Shown Are Combined for All Locations. 

Aspect Treatment Year 1 Year 2 

North Unburned 3,365 3,472 

North Burned 4,260 5,298 

South Unburned 6,658 5,191 

South Burned 22,660 18,006 

The diameter distribution of stumps with at 

least one living basal sprout is perhaps more 

important than total numbers of sprouts. Sprouts 

from smaller diameter stumps are a most desirable 

form of hardwood regeneration (Sanders 1971). The 

number of oak stumps (<5 cm) with at least one 

living basal sprout was significantly greater on 

burned plots after two years (Table 4). This 

difference is largely attributed to the fact that 

burning top-killed small hardwood stems, thereby 

promoting basal sprouting. On unburned plots, 

these small stems continued to grow and produced 

no basal sprouts. Therefore, they were not 

considered to be small stumps. Regeneration 

starting over from new sprouts may be more 

desirable than flat-topped individuals which 

existed in the understory because of potentially 

better growth form (Teuke and Van Lear 1983, 

OVHara 1986). 

Table 4.--Number of Stumps (Per Acre) With at 

Least One Living Basal Sprout by Diameter Class 

Two Years Following Burning. Data Shown Are 

Combined for A11 Locations. 

Diameter Class (cm) 

<5 5-9 10-1 4 > 15 

Burned 1,468 608 466 751 

Unburned 50 1 2 15 287 787 
Regeneration by sprouting was prolific on both 

burned and unburned plots, Wowever, burning 

improved sprout quality by promoting basal 

sprouting. Burning increased the total number of 

basal sprouts for both the oak and miscellaneous 

species groups. Since basal sprouts are well 

anchored and tend to resist decay, the effect of 

burning is considered favorable. While increased 

sprouting by miscellaneous species following 

"burning will benefit browsing wildlife, these 

sprouts will probably not be a major component in 

the upper canopy of the mature stand because of the 

long-tern competitive nature of oaks. 

The greatest number of basal sprouts was on burned plots with southerly aspects, indicating the 

importance of high intensity fires in establishing 

well-anchored sprouts which can develop free from 

defect and decay. Fires of the desired intensity 

on northern aspects may be more readily achieved by 

burning in the summer rather than in the fall. 

Numbers of small stumps (<5 cm) having at least one living basal sprout were greater on burned plots 

two years after treatment, Because small stumps 

tend to produce a minimum of sprouts and yet give 

rapid height growth, they provide the most 

desirable coppice regeneration. 

results of this study indicate that burning 

improves the origin af hardwood sprouts and may 

increase numbers of small stumps having at least one basal sprout, the long-term effects of burning on the composition and quality of hardwood stands 

needs further research. 

LITERATURE CITED 

Bechtold, W. A. and D. R. Phillips. The hardwood resource on nonindustrial private forest land in 

the Southeast Piedmont. USDA Forest Service Res. 

Pap. SE-236; Southeastern Forest Experiment 

Station, Asheville, NC; 1983. 19 p. 

Danielovich, S. J., D. H. Van Lear, S, K. Cox, and 

M. K. Augspurger, Burning in Southern Appalachian 

logging slash--effects on residual vegetation and 

regrowth. In Central Hardwood Forest Conference, 

Feb. 24-26,7987. University of Tennessee, 

Knoxville, TN; 1987. (In Press). 

Harlow, R. F, and D. W. Van Lear. Silvicultural 

effects on wildlife habitat in the South (an 

annotated bibliography) 1953-1979. Clemson Univ. 

Dept. of Forestry Tech. Pap. No. 14, Clemson 

University, Clemson, SC; 1981. 30 p. 

Jensen, R, F, Oxygen and carbon dioxide concentration in sound and decaying red oak trees. For. 

Sci. L5:246-251; 1969. 

Keetch, J. J. Sprout development on once-burned 

and repeatedly burned areas in the Missouri 

Ozarks, USDA Forest Service Research Tech. Pap. 

137, Central States Experiment Station; 1944, 

22 p. 

Moak, 3. E., W. F. Watson, and M. S. Watson. 

Costs of forestry practices in the South. For, 

Famer Hanual ed. 43:26-32; 1983. 

O'Hara, K, L. Developmental patterns of residual 

oaks and oak and yellow poplar regeneration 

after release in upland hardwood stands, South. 

J. Appl. For. 10:244-248; 1986. 

Roth, E. R. and B. Sleeth. Butt rot in unburned 

sprout oak stands. USDA Technical Bulletin 684; 

1939. 43 p. 

Sanders, I, L. Height growth of new oak sprouts 

depends on size of advance reproduction. 

Journal of Forestry 69:809-811; 1971. 

Shigo, A, L. Tree decay, an expanded concept. 

USDA Agric. Inform. Bull. 419; 1979. 73 p, 

Smith, C. H. Natural regeneration and intensive 

cultural practices in central Appalachian 

hardwood stands using clearcutting and selection 

cutting practices. In Proc.: 1979 John S. 

Wright Forestry Con£, Regenerating Oaks in 

Upland Hardwood Forests, p. 30-42. Purdue 

Univ., West Lafayette, Ind.; 1979. 

Tansey, J. B. Forest statistics for north 

Georgia. USDA Forest Service Res. Bull. SE-68. 

Southeastern Forest Experiment Station, 

Asheville, NC; 1983. 29 p. 

Teuke, M. J, and D. H. Van Lear. Prescribed 

burning and oak advance regeneration in the 

southern Appalachians. Georgia For. Corn. Res. 

Pap. 30; 1982. 11 p. 

Waldrop, T. A., E. R. Buchner, and J. A. Muncy. 

Cultural treatments in low-quality hardwood 

stands for wildlife and timber production. 

p. 493-500. In E. Shoulders, ed. Proceedings 

Third ~ienniarsouthern Silvicultural Research 

Conference, Atlanta, GA. USDA For. Sen. Gen. 

Tech, Rep. SO-54; 1985. 

Watt, R. F. The need for adequate advance 

regeneration in oak stands. Proc.: 1979 

John S. Wright Forestry Conf. Regenerating Oaks 

in Upland Hardwood Forests, p. 11-17. Purdue 

Univ., West Lafayette, Ind.; 1979. 

Wood, G. W. (ed.). Prescribed fire and wildlife 

in southern forests, Proc. of a symposium. 

April 6-8, 1981. Myrtle Beach, SC, 170 p., The 

Belle W. Baruch Forest Science Institute of 

Clemson Univ., Georgetown, SC; 1981. 
Prescribed Burning in Mature Pine-Hardwood 

Stands--Effects on Hardwoods and Small Mammals 1 

D. L, Sanders, D. H. Van Lear and D. C. Guynn 2 

ABSTRACT.--Winter prescribed fire in mature pine-hardwood stands 

(60-95 years old) in the Southern Appalachians had little or no 

adverse effect on large hardwood crop trees. Hardwoods 215.5 inches 

in diameter exhibited no cambium damage in the first year after 

burning. Only five percent of hardwood stems between 5.5 and 12 

inches in diameter showed short-term evidence of cambium damage from 

burning, suggesting that low intensity prescribed burning in mature 

hardwood stands will have minimal impacts on stem quality, The 

low-intensity fires top-killed hardwoods <2 inches in diameter and 

encouraged them to sprout. Forbs and grasses did not increase after 

burning, probably because full stocking of the overstory limited light 

reaching the forest floor, Trapping studies indicated that mature 

pine-hardwood stands were poor habitat for small mamals. Their 

populations were not changed by a single low intensity fire. 

INTRODUCTION 

In recent years, winter backing fires of low 

intensity have been used for wildlife management 

purposes in mature hardwood and pine-hardwood 

stands in mountainous terrain of the Sumter 

National Forest, South Carolina, Whether these 

low-intensity prescribed burns during the dormant 

season cause cambium damage to mature crop trees 

in hardwood stands is uncertain (Van Lear and 

Johnson 1983). Early studies (Hepting and Hedgecock 1937, Nelson et al. 1933) linked heartrot in 

hardwoods to basal scarring by fire, but this 

damage generally followed higher intensity 

wildfires. 

Prescribed burning, primarily in pine stands, 

has been a major part of wildlife management in 

the South since the early 1930's (Stoddard 1931). 

Even though fire is often used as a wildlife 

management tool, lietle is known about the effects 

on small mammals which utilize the forest floor 

for food, nesting, and hiding cover. This is 

especially true in mature mixed pine-hardwood 

stands. 

The objectives of this study were: 1) to 

determine effects of dormant season backing fires 

in mature pine-hardwood stands on the cambium of 

larger hardwood stems 2) to measure response of 

understory vegetation to this type of burning in 

the Southern Appalachian Mountains and 3) to 

evaluate effects of these fires on small mammal 

populations, 

'paper presented at the 4th Biennial Southern 

Silvicultural Research Conference, Atlanta, GA., 

November 4-6, 1986. 

'~ormer Graduate Assist ant and Professors, 

respectively, Department of Forestry, Clemson 

University, Clemson, SC. 

STUDY AREA 

The study was conducted on the Sumter 

National Forest in South Carolina. The study area 

is part of the Appalachian Hardwood subregion of 

the Southern Hardwood region (Barrett 1980). 

Normal annual precipitation, based on a 30-year 

average, is 66 inches. Average daily minimum 

temperature is 46OF and the average maximum is 

70°F. 

Soils were predominantly of the Brevard, 

Chandler, and Evard series and are classified as 

Typic Hapludults. Slopes ranged from 3 to 30 

percent. 

MATERIALS AND METHODS 

Effects of low-intensity winter backing fires 

on cambium damage in hardwood >3 inches in 

diameter were examined in two mature plne-hardwood 

stands using a technique modified from Kay11 

(1963). Two months after burning, two cambium 

samples were taken from the charred area of the 

lower bole of six species. Ten trees in each of 

four diameter classes (3-5.5, 5.6-10,5, 10,6-15.5, 

and >15.5 inches) were sampled for each species. 

Diameter was measured at 4.5 ft above ground. For 

certain species, it was not possible to locate ten 

trees in the larger diameter classes, so 8 or 9 

trees were used. Cambium samples were extracted 

about I ft above the ground using a size 14 

leather punch and placed in a 1 percent solution 

of 2, 3, 5 triphenyl tetrazolium chloride (TTC). 

Samples were refrigerated 24 to 36 hr, sliced in 

half, and examined visually, A pink cambium 

indicated that cells were alive, implying no 

short-term adverse effect of burning on the 

cambium. Failure of the sample to turn pink 

indicated that the cambium cells were dead and 

implied fire damage to the tree bole. 

Stands sampled to determine effects of fire 

on stem quality of hardwood trees were burned in 

March using backing fires which moved down slope 

at a rate of about 1 ftlmin, Maximum temperature 

during burning ranged from 48 to 64"F, Windspeed 

was 5 mph with a southerly or westerly direction, 
Responses of understory vegetation and small 

mama1 to low-intensity winter burning 

were evaluated in two other mature mLxed 

pine-hardwood stands. These were different stands 

from those used to examine the effect of burning 

on hardwood stem quality, but were similar in age, 

composition, and site conditions. This portion of 

the study was installed in a randomized complete 

block design on four 1.24 ac plots, In each 

stand, one plot was randomly selected for burning 

and the other sewed as a control. Burning was 

conducted in February and March using back-firing 

techniques under conditions similar to those 

described above. Understory vegetation was 

sampled on two perpendicular 3.3 by 32.8 ft 

transects and a circular subplot (radius 16.4 ft) 

located at each of eight random points on each 

plot. Preburn biomass of vegetation c2 ft was 

clipped afrer counting woody and herbaceous stems 

from a 3-3 ft radius circle at the center of each 

subplot, Subsequent tallies and clipping of 

vegetation were conducted in the 3rd and 4th 

quarters of the circular subplot. Biomass was 

estimated just prior to burning and 16 months 

after burning. 

in the 5.6 to 10.5 inch and 10.6 to 15.5 inch 

diameter classes indicated cambium damage from the 

fire. Trees in the Largest diameter class showed 

no evidence of cambium damage in the two months 

after burning. Indications of damage in Table 1 

are high because many trees in the stand were not 

charred and therefore were not sampled. 

Table I, Percentage of sampled hardwood trees 

exhibiting cambium damage following dormant season 

backing fires on the Sumter National Forest, South 

Carolina. 

DIAMETER CLASS (Inches) 

3-5.5 5.6-10.5 10.6-15.5 15.6 and 

above 

-%- 

Red oak 10 0 I I 0 

White oak 27 0 0 0 

Hickory 30 1 I. 10 0 

Blackgum 10 0 0 0 

Red maple 20 10 0 0 

Yellow-poplar 20 10 0 0 

Small Elamma1 Sampling 

Average 20 5 4 0 

Small mammals were collected using mouse 

traps and drift fences with pitfalls, Each plot 

had 28 trap stations. The drift fence was located 

in the center of each plot and consisted of three 

16.4 ft by 20 inch legs of aluminum flashing. At 

the end of each leg, a 19-quart plastic bucket was 

installed flush with the ground. 

Trapping was conducted four different times. 

For each trapping period, 84 Victor mouse traps 

were set on each site (3 traps at each of the 28 

stations) and drift fences were opened by removing 

the lids from the buckets. Traps were baited with 

peanut butter and buckets were filled with water 

to drown the animals. The first trapping in 

February of 1984 was conducted for four consective 

nights (one night of prebaiting and three nights 

with traps set and buckets open). The second 

trapping was conducted after prescribed burning in 

June of 1984 for six nights. One night of 

prebaiting was still used, but the number of 

nights traps and buckets were open was increased 

to five nights. The third and fourth trappings 

were also done for six nights and yere in late 

Novder - early December and June, respectively. 

During trapping periods, traps were checked once 

every morning. 

The probability of capture, 0, (# animals 

caught/# traps actually available for capture) was 

calculated for each treatment during each trapping 

period. Because these probabilities were so low, 

no statistical tests were conducted, 

RESULTS AND DISCUSSION 

Cambium damage to hardwood trees 

About 20 percent of the sampled hardwood 

trees 3 to 5.5 inches in diameter showed evidence 

of cambium damage from the low-intensity winter 

burn (Table I). Only 4-5 percent of sampled trees 

Four of the six species sampled in the 

10.6-15.5 inch diameter class showed no evidence 

of cambium damage. However, I1 percent of the red 

oaks in this size category and 10 percent of the 

hickories indicated some degree of cambium damage. 

These species would be expected to be more 

heat tolerant than such species as red maple (Hare 

1965). It is possible that difficulties in 

extracting samples and judging color of cambium 

samples following soaking in TTC occasionally 

resulted in a false determination of damage. 

The data showed that smaller trees are more 

susceptible to cambium damage during burning, 

probably because small trees have thinner bark. 

Hare (1965) found that bark thickness was closely 

related to the time for the cambium to reach 

lethal temperatures. 

Flame heights for these low-intensity backing 

fires averaged about 4-6 inches. Fires of this 

intensity apparently have little, if any, adverse 

short-term effect on the cambium of large 

hardwoods (>15.5 inches) and only minor impact 

(5%) on trees of medium size (5.6-15.5 inches). 

Most trees of this size would be sold as pulpwood, 

rather than sawtimber, so tree quality would not 

be a major consideration, 

These data indicate that low-intensity fires 

can be judiciously used late in the rotation for 

wildlife habitat improvement in hardwood or mixed 

pine-hardwood stands under even-age management 

with little concern for effects on stem quality of 

crop trees. Damage to small diameter trees late 

in a rotation is of little consequence, since such 

trees are not crop trees. When mature even-age 

stands are harvested, small unmerchantable trees, 

fire damaged or not, should be felled allowing an 

even-aged coppice hardwood stand or a mixed orgin 

pine-hardwood stand to regenerate. 
Effects on understory vegetation 

Burning top-killed most of the small 

(<2 inch) hardwood understory stems in the mature 

pine-hardwood stands. About 98 percent of the 

fire-damaged small. hardwood trees sprouted. 

Average diameter of the top-killed trees ranged 

from 0.4 to I.1 inches (Table Z), indicating that 

trees greater than about 2 inches in diameter are 

not likely to be top-killed by similar lowintensity burns. The average number of sprouts 

per stump ranged from 2 to 8 one year after 

burning, while the average height of the tallest 

sprout was from 1 to 5.5 it. This increase in 

sprouting is the major wildlife benefit from this 

type of burning, Many studies have documented the 

improved palatability and nutrition, as well as 

better accessibility, of new sprouts following 

burning. 

Density and biomass of woody ground 

vegetation (62 ft tall) tended to increase after 

the burn, but due to the large variance between 

plots the increase was not significant (Table 3). 

Table 2. Average preburn diameter of top-killed 

understory hardwoods and the number and height of 

sprouts following winter burning in mature 

pine-hardwood stands. 

AVERAGE AVERAGE 

PREBURN AVERAGE HEIGHT OF 

DIAMETER SPROUTSfSTW TALLEST SPROUT 

(in) (ft) 

Red maple 0.59 

Red oak 0.94 

Sourwood 0.67 

White oak 0.63 

Yellow-poplar 0.75 

Black cherry 1.10 

Black gum 0.51 

Dogwood 0.75 

Hawthorn 0.39 

Horse sugar 0.87 

Table 3, Woody vegetation (<2 ft tall) density 

and biomass on burned and unburned plots in mature 

pine-hardwood stands on the Sumter Rational Forest 

in South Carolina. 

BURNED CONTROL 

TIME 

DEBSITY BTGWSS DEKSITY BIOMASS 

Before Burning 117,915 5 0 145,749 51 

1 Year After 225,202 0 1 l53,846 38 

Burning 

Biomass of forbs and grasses did not increase 

after burning because full overstory stocking 

limited light reaching the forest floor. 

Small mammals 

Few small mammals were caught on either 

burned or unburned plots in the year following 

treatment (Table 4). Three families and six 

species were caught on the burned plots, Only 

twelve individuals were captured on burned plots, 

with the white-footed mouse, deer mouse, and the 

pygmy shrew making up 75 percent of the total. 

Only two families and two species were caught on 

the control plots with northern short-tailed shrew 

and southeastern shrew comprising ?5 percent of 

the eight individuals captured. The pygmy shrew, 

caught twice on a burned site, had never been 

recorded in South Carolina. 

Small mammals, such as moles, mice, shrews, 

and ground squirrels are important members of the 

forest ecosystem (Dueser and Shugart 1978), but 

little is known about their population densities 

in upland hardwood stands of the Southeast. 

Numbers of small mammals captured in this study 

were too small for statistical analysis. Pearson 

(1959) and Atkeson (1974) found the relative 

abundance of small mammals changed with the types 

and amounts of vegetative cover. When 

successional stages advance, small mammal 

diversity and abundance decrease, and only a few 

species benefit in developing older forests. The 

study area contained few seed-bearing grasses and 

forbs found in younger open stands which are 

necessary for small mammals to thrive. Because of 

lack of desirable vegetation for food and cover, 

small mammal populations were sparse on the study 

sites both before and after burning. 

CONCLUSIONS 

Minter burning using low-intensity backing 

fires caused no cambium damage to large (215 inch) 

stems in mature hardwood stands. Medium-sized 

(5.6-15.5 inches) hardwood trees also exhibited 

little cambium damage. Based on these results, we 

conclude that winter backing fires under weather 

and fuel conditions similar to those in this study 

can be effectively used in mature pine-hardwood 

stands to improve wildlife habitat for certain 

species without fear of excessively damaging 

larger hardwood trees. Fire damage to smaller 

trees is of little consequence with regard to 

timber production in even-age management systems 

following harvest. All residual trees should be 

clearfelled because sprouts from stumps and 

advance regeneration have better growth potential 

than small residual trees (O'Hara 1986). 

Top-kill or damage to small (c2 inches) 

hardwoods encourages sprouting which benefits 

large browsing wildlife species such as deer. 

However, mature hardwood stands in the southern 

Appalachian Mountains are poor habitat for small 

mammals. The Pow-intensity prescribed burning was 

not hot enough to alter the habitat variables, 

e'g., seed production by herbaceous plants, 

important to many small mammals. Burning in 

mature mixed pine-hardwood stands could not be 
considered beneficial or harmful to small mammals, 

but certainly would benefit other wildlife species 

which thrive on new sprout growth. 

Table 4. Number of small mammals captured on 

pine-hardwood sites on the Sumter National Forest, 

South Carolina (1984-85). 

- - 

FAMILY /SPECIES BURN CONTROL TOTAL 

Cricet idae 

White-f ooted Mouse 5 

Deer Mouse 2 

Golden Mouse -- 

Woodland Vole -- 

Zapodidae 

Meadow Jumping Mouse 1 

Soricidae 

Northern Short-tail Shrew 1 

Southeast ern Shrew -- 

Smokey Shrew -- 

Pygmy Shrew 2 

Least Shrew 1 

Total No. of Individuals 12 8 20 

Dueser, R. D. and H. H. Shugart, Jr. Microhabitat 

in a forest-floor small mammal fauna. 

Ecology 59:89-98. 1978. 

Hare, R. C. C~ntribution of tark to fire 

resistance of southern trees. J. Forestry. 

63:248-251. 1965. 

Hepting, G. H, and G. G. Hedgecock. Decay in 

merchantable oak, yellow poplar, and basewood 

in the Appalachian region. U.S. Dept. Agr. 

Tech. Bull. 570, Asheville, NC; 1937. 30 p. 

Kayll, A. J. Heat tolerance of Scots pine seedling cambium using tetrazolium chloride to 

rest viability. Dept. of Forestry Canadian 

Publ. No. 1006. 1963. 12 p. 

Nelson, R. M., I. H. Sims, and M. S. Abell. Basal 

fire wounds on some southern Appalachian 

hardwoods. J. Forestry 31:829-837. 1933. 

O'Hara, K. L. Developmental patterns of residual 

oaks and oak and yellow poplar regeneration 

after release in upland hardwood stands. 

South. J. Appl. For. 10:244-248. 1986. 

Pearson, P. G. Small mammals and old-field 

succession on the Piedmont of New Jersey. 

Ecol. 40:249-255. 1959. 

Stoddard, H. L. The bobwhite quail: its habits, 

preservation, and increase. Charles 

Scribner's Sons, New York. 1931. 559 p. 

LITERATURE CITED 

Atkeson, T. D. Succession of small mammals on 

pine plantations in the Georgia Piedmont. 

M.S. Thesis, Univ. of Georgia, Athens, GA. 

1974. 66 p. 

Van Lear, D. H. and V. J. Johnson. Effects of 

prescribed burning in the Southern Appalachian and upper Piedmont forest: a review. 

Dept. of Forestry Bull. No. 36, Clemson 

Univ., Clemson, S.C.; 1983. 8 p. 

Barrett, J. W. (ed). Regional silviculture of the 

United States. 2nd ed. John Wiley and Sons, 

NY. 1980. 551 p. 
PRESCRIBED FIRE FOR PRECOWRCIAL THINNING IN A 

 om-YEAR-OLD LOBLOLLU PINE STMD' 

Thomas A. Waldrop and F. Thomas LloydL 

Abstract.--A two-phase study was conducted to determine 

the feasibility of using prescribed fire to thin young, 

naturally regenerated loblolly pine stands. In Phase I, 

survival after winter backing, strip head, flanking, and 

spot fires was compared. Backing fires were chosen for 

Phase I1 on the basis of survival of the largest trees and 

uniformity of thinning. In Phase 11, burning produced the 

effect of a thinning from below and reduced density from 

6,800 to 2,850 stems per acre (58 percent). Crown scorch 

was heavy but needle consumption was in£ requent . Much of 

the study area remained overstocked with few spots being 

understocked. Diameter growth of surviving trees was unaffected but height growth was reduced by 33 percent. 

Precommercial thinning of dense natural stands with fire 

shows promise but needs additional study before general 

recommendations can be made. 

Keywords: crown scorch, needle consumption, South Carolina, 

nearest neighbor. 

INTRODUCTION 

Coastal Plain stands of loblolly pine (Pinus 

taeda L.) are often regenerated by natural means, 

whether by design or by accident. Since large 

seed crops are produced almost every year in this 

region (Langdon 1981), young stands are usually 

dense. On the Francis Marion National Forest, 

approximately 1000 acres of such stands are3handthinned annually at a cost of $55 per acre. 

Prescribed burning could be a less expensive 

method of precomercial thinning that would provide the additional benefit of protecting stands 

from wildfire at a younger age than is currently 

practiced. 

Even though prescribed fire is generally not 

recommended for sapling-sized stands, its feasibility for precommercial thinning has been studied 

for several species. The first studies were with 

uneven-aged Ponderosa pine (x. ponderosa Laws. ) 

stands (Weaver 1947; Morris and Mowat 1958; and 

Wooldredge and Weaver 1965). Because some areas 

were too heavily thinned while others were not 

thinned enough and height growth was reduced, a 

summary task force on fire in the Northern Rocky 

Mountains (Roe and others 1971) did not recommend 

prescribed burning for precommercial thinning in 

western pines. Muraro (1977) concluded that 

prescribed burning should not be conducted in 

lodgepole pine (2, contorta Dougl.) stands younger 

than 25- to 30-years-old due to a lack of surface 

fuels and susceptibility to Ips beetle attack. 

In the South, precommercial thinning with fire 

was recommended by McNab (1977) for loblolly pine 

stands and Nickles and others (1981) for shortleaf 

pine (P. echinata Mill.) stands with a large range 

of tree sizes. In both studies, burfiing acted as a 

thinning from below with high mortality only in the 

smallest size classes. A high negative correlation 

existed between mortality rates and bark thickness 

at the root collar. 

Paper presented to the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

2 The authors are Post-Doctoral Research 

Associate, Department of Forestry, Clemson 

University, Clemson, SC and Research Forester, 

USDA Forest Service, Southeastern Forest 

Experiment Station, Charleston, SC. 

3 Personal communication, Glen Stapleton, 

Assistant District Ranger, USDA Forest Service, 

Francis Marion National Forest, Witherbee Ranger 

District, Huger, SC. 

For prescribed burning to be a successful tool 

for thinning young pines, data is needed to 

describe how various burning techniques affect survival, growth, and spacing of stands over a wide 

range of conditions. This paper describes the 

results of a two-phase study of the feasiblilty of 

using prescribed fire to thin young, naturally 

regenerated loblolly pine stands. The first phase 

compared four burning techniques and selected the 

best on the basis of survival of largest trees and 

uniformity of thinning. The burning technique 

selected in the first phase was used in the second 

phase to study survival, growth, and uniformity of 

stocking. 
The study is located on the Santee Experimental 

Forest in Berkeley County, South Carolina at an 

elevation of approximately 25 feet above man sea 

level, Soils are Aerie Ochraquults of the Wahee 

series and are somewhat poorly drained and slowly 

pemeable. Slopes range from 0 to 4 percent, 

Site index for loblolly pine at age 50 is 86 feet. 

At the time of study establisbent (Winter 1986), 

the stand was 4-years-old consisting almost 

entirely of loblolly pine saplings resulting from 

seeding from adj acent stands. Diameters at breast 

height ranged from less than 0.5 inch to 2.6 

inches with a mean of 0.6 inch. Tree heights 

ranged from less than 5 feet to 15.6 feet with a 

mean of 7-3 feet. Stocking was at aproximately 

6,800 stems per acre. 

The previous stand was clearcut in November 1981 

after a winter prescribed burn and 3 annual summer 

burns. Logging slash was burned the following 

March, The area was then planted with loblolly 

pine seedlings on an 8 by 12 foot spacing. 

However, survival of planted seedlings was less 

than 20 percent due to an infestation of Pales 

weevil. After planting, the area was fertilized 

with 250 pounds per acre of 0-46-0 triple 

superphosphate. 

PHASE X 

Four burning techniques were tested to determine 

the wst feasible for thinning a sapling-sized 

stand. Each of four study plots, 130 by 60 feet 

in size, was burned by either a backing fire, 

strip headfire, flanking fire, or a spot fire with 

a 6 by 6 foot spacing between spots. Burns were 

conducted on January 17, 1986, 6 days after a 

rainfall of 0,56 inch. Burning began at 12:OO pm 

with a temperature of 70 degrees F, and a relative 

kuunidity of 42 percent. Winds were from the 

southeast at a speed of 4 to 7 miles per hour, 

Surface fuels were light on all plots. However, 

dried broomsedge (Andropogon virginicus L.) 

covered most of the area and carried the fires. 

A strip headfire was conducted by setting a 

backing fire followed by strips at 5 to 8 foot 

intervals. Flame heights remained at 2 to 3 feet 

except where strips came together and flames overtopped some trees, This variability in fire 

intensity was intentional to kill some trees while 

leaving others. 

The backing fire traveled into the wind at a 

rate sf 1.5 feet per minute. Flante heights 

remained miform at I to 2 feet with no evidence 

of flames reaching the lowest tree limbs. The 

Backing fire was intended to girdle the stems of 

small diameter trees while leaving larger trees 

alive. 

The flanking fire began with a backing fire perpendicular to the wind, followed by several flanks 

aproximately 15 feet long set parallel to the 

wind, Resulting flames were variable in height, 

ranging from 1 foot or less where flanks backed 

into the wind to levels above treetops where 

flanks came together, As with a strip headfire 

the variable fire intensity was intentional ts 

kill only a portion of the stand, 

The spot fire was started first with a backing 

fire, then spots were set on a 6 by 6 foot spacing 

while mving into the wind, The method was 

intended to cover the plot with fire quickly while 

putting spots close enough to prevent flames of 

high intensity. However, thi. method produced a 

high intensity fire over the entire plot with flames overtopping most trees. Therefore, this 

method was not considered feasable for precomercia1 thinning in such young stands and was not 

included in subsequent measurements, 

An estimate of survival was conducted 2 weeks 

after burning in plots where backing, strip headfire, and flanking fires were used. A random 

sample of 100 trees was selected in each plot and 

the cambium of each tree observed. Trees were 

assumed to be dead or dying if more than 50 percent of the circumference of the cambium at ground 

level was brown. Each tree was tallied as alive 

or dead and total height was measured. 

Results 

Mortality by height class is compared for three 

burning techniques in Figure 1, For all burning 

techniques, mortality was high in the two smallest 

size classes (less than 9 feet and 9 to 12 feet) 

and relatively low among the largest trees (over 

12 feet), thus producing the effect of a thinning 

from below. Among the largest trees, survival was 

highest with the backing fire (68.7 percent) as 

compared to the flanking fire (50 percent) and 

strip headfire (57.1 percent). Since the flanking 

and strip headfires produced variable fire intensities, some spots were too heavily thinned while 

others were not thinned enough. Thinning was most 

uniform over the entire plot with the backing 

fire. Therefore, backing fires were selected for 

use in Phase XI of this study. 

Backing Fire 

9 - 12 feat 7i.7 

> 12 feet 

Flanking Fise 

< 9 feet 88.2 

9 - i2 feet 

> 12 feet: 

Str f g HeadP ire 

< 9 feet 

9 - 12 flsat 

Figure 1.--Percent mortality by height class two 

weeks after winter prescribed fires of various 

techniques. 
PHASE I1 

The study was established as a split-plot randomized complete block design with five replications, two whole plots per replication, and two 

subplots per whole plot. Whole plots were 131 

feet square (0.4 acre) and assigned to blocks on 

the basis of having similar pretreatment stocking 

and size distributions. Each plot within a replication was randomly selected to be burned or left 

as an unburned control. Whole plots were split 

into fertilized and unfertilized subplots to 

observe the interaction of burning with fertilization, which should accelerate the growth of 

dominant trees, Fertilized subplots received 

triple superphosphate and urea at levels of 25 

pounds P and 200 pounds N per acre. 

were converted to point estimates of density by 

the method of Thompson (1956). Measurement of 

distance to the nearest tree and the nearest live 

tree allowed a comparison of densities before and 

after burning. 

The effect of burning on tree growth was studied 

by comparing dbh and height growth between burned 

and control plots. In each 0,04 acre sample plot, 

both in fertilized and unfertilized subplots, the 

dbh and height of each of 40 trees was measured at 

the beginning and end of the 1986 growing season. 

Sample trees were selected as the largest on each 

sample plot since those would be most likely to 

survive the burning treatment and reach rotation 

age. Paean subplot dbh and height growth were compared by analysis of variance. 

RESULTS AND DISCUSSION 

Burninn Conditions 

Backing fires were conducted on February 3, 1986, 

4 days after a rain of 0.42 inch and 7 days after 

a rain of 0.91 inch. Burning began at approximately 12:30 pm with a temperature of 70 degrees F. 

and a relative humidity of 38 percent. Winds were 

from the southwest at 3 to 5 miles per hour. 

Fuels along the ground were light and moist but. 

the entire study area was covered with dried 

broomsedge which carried the fires. Flames were 

generally 1 to 3 feet in height (6 to 26 

Btu/second/foot using Byrams flame length index, 

Brown and Davis 1973). Occasionally, flames 

reached 4 to 5 feet in height (116 to 188 

Btu/second/foot) where vertical fuels (broomsedge 

and needle drape) were heavy. The mean rate of 

spread over all replications was 3 feet per 

minute. Burning was concluded at approximately 

1:30 pm. 

Measurements 

Measurements were taken in each of the five 

replications to examine the degree of crown scorch 

and needle consumption resulting from backing 

fires, survival by size class, uniformity of 

stocking before and after burning, and growth of 

survivors in burned and control plots, In May 

1986, 3 months after burning, degree of crown 

scorch and needle consumption were estimated for 

every tree over five feet tall on a 0.04 acre 

sample plot in each of the 10 burned subplots. 

For each tree, the height to the bottom of the 

crown, highest point of needle consumption, 

highest node with scorched needles, total height, 

and dbh was measured, Crown scorch and needle 

consumption were expressed as a percentage of the 

length of the crown before burning. Each tree was 

tallied as alive or dead to compare size distributions before and after burning and to relate mortality to degree of crown damage. 

Stocking levels before and after burning were 

estimated at 54 randomly selected points 

throughout each burned plot to examine uniformity 

of thinning. The nearest neighbor technique 

(Clark and Evans 1954) was used by measuring the 

point to the nearest tree (either alive or dead) 

and to the nearest live tree. Measured distances 

Mortalitv and Size Distribution 

Prescribed burning reduced the total number of 

stems per acre from 6,800 to 2,850 (58 percent). 

The highest mortality rates were in the lower 

diameter (Figure 2) and height (Figure 3) classes. 

Mortality was 88 percent and 53 percent in the 0.2 

inch and 0,6 inch diameter classes, respectively. 

The 6 foot height class had 80 percent mortality 

while the 8 foot class had 47 percent. Mortality 

in the upper dbh and height classes was near zero. 

The pattern of thinning was silviculturally 

desirable, resembling a thinning from below. 

Burning changed the diameter and height distribution from a reverse-J pattern, with large numbers 

of small trees, to a bell-shaped pattern with 

medium-sized trees being most frequent (Figures 2 

and 3), As a result, mean tree dbh increased from 

0.6 inch to 0.9 inch and mean tree height 

increased from 7.3 feet to 8.4 feet. Even though 

burning substantially reduced the total number of 

stems, the stand was still dense. A burn of 

somewhat higher intensity may kill more trees in 

the small size classes, thus better improving 

growing conditions for the larger survivors. 

These results closely resemble those of McNab 

(1977) in a much older (17.5 years) loblolly pine 

stand. 

Crown Damage and Mortality 

Crown damage due to backing fires was heavy in 

all study plots, Over 5,500 trees per acre (81 

percent) recieved at least 40 percent crown scorch 

while over 4,200 trees per acre (62 percent) were 

totally scorched. Even though crown scorch was 

heavy, the incidence of needle consumption was 

low. Only 26 percent of all trees showed evidence 

of needle consumption, 

Several studies have shown mortality of polesized or larger pines with severe crown scorch 

(Storey and Merkel 1960; Methven 1971; Villarrubia 

and Chambers 1978; and Waldrop and Van Lear 1984). 

When working with trees generally less than 20 

feet tall, Wade (1985) found that degree of needle 

consumption was a better predictor of mortality 

than crown scorch. We showed that survival was 
Trees DBP Acre 

Class (inches) 

Figure 2,--Change in diameter (dbh) distribution 

of a 4-year-old loblolly pine stand after a winter 

backing flre, 

T~ees osr Acae 

3500 n~illed 

3000 a~urv ived 

a00 

Height Class (feet) 

Figure 3.--Change in height distribution of a 

4-year-old loblolly pine stand after a winter 

backing fire. 

less than 50 percent among trees with 20 percent 

needle consumption or more. Figure 4 shows the 

rate of mortality of trees with various degrees of 

crown scorch and needle consumption in this study. 

Mortality was low among trees with less than 80 

percent crown scorch. Above the 80 percent crown 

scorch level, mortality becomes very high. 

Similar to Made" findings, mortality was over 50 

percent when needle conswption was 20 percent or 

more, 

Mortality occurred even at low levels of crown 

scorch (Figure 41, indicating that crown damage 

may not be the only cause of mortality. McNab 

(1977) and Nickles et al. (1981) found a strong 

correfaticil between survival and bark thickness at 

the root collar, suggesting that mortality was 

caused by stem damage. Although not conclusive, 

these data suggest that mortality after a backing 

fire in a sapling-sized stand may be caused by 

both crown and stem damage. 

Pct Mortality 

Pct Crown Scorch end Needle Consumption 

Figure 4.--Percent mortality by percent crown 

scorch and needle consumption after a winter 

backing fire. 

Uniformity of Stocking 

The percentage of the total study area stocked 

at various levels before and after burning is 

shown in Table 1. Before burning, the majority 

(80.1 percent) of the study area was overstocked. 

For the purpose of this paper, overstocked is 

defined as 1600 stems per acre or more, After 

burning, the majority of the area (54.3 percent) 

was stocked at levels of 400 to 1,200 stems per 

acre, which are acceptable for many forest products. The remaining 45.7 percent of the area was 

still overstocked with densities as high as 12,000 

stems per acre, yielding a mean of 2,850 stems per 

acre. However, a single prescribed backing fire 

effectively lowered stocking levels over the 

entire study area. In addition, areas that were 

understocked (fewer than 400 stems per acre) were 

essentially absent. The absence of understocked 

areas indicates that backing fires are preferable 

to flanking and strip headfires where hot spots 

and, therefore, areas of high mortality are more 

frequent. 

Table 1.--Percentage of the total study area 

stocked at various densities before and af ler 

burning. 

Stems per Before After 

Acre Burning Burning 

(Pet) (Pet 1 

400 3.5 27,9 

800 10.0 17-1 

1200 6,s 9,3 

1600-6 80.0 45.7 

Total 100 100 
Tree Growth A;?SD CONCLUSIONS 

When crown damage from burning is high, as with 

this study, pine growth is of ten reduced (Johansen 

1975 and 1984; McCulley 1950), Johansen and Wade 

(1985) reported the loss of an entire yearf s 

diameter growth in trees with severe crown scorch, 

In this study, an analysis of variance showed no 

significant differences in mean diameter growth of 

sampled trees in burned and unburned study plots, 

regardless of whether they had been fertilized 

(Table 2). Fertilization significantly increased 

diameter growth on burned and unburned plots. 

Table 2.--Diameter (dbh) and height growth one 

growing season after a winter backing fire. 

Treatment DBH Growth Height Growth 

(in) (feet) 

Burned - No Fertilizer 0.31 a' 1.8a 

Unburned - No Fertilizer 0.37 a 2.7 b 

Burned - Fertilized 0.47 b 2,Oa 

Unburned - Fertilized 0.48 b 2.6 b 

1 Means followed by the same letter within a 

column are not significantly different at the 

5 percent level. 

Height growth of sample trees was adversely 

affected by a single winter backing fire (Table 

2). In plots that were not fertilized, height 

growth averaged 2.7 feet in unburned controls the 

year after burning as compared to only 1.8 feet in 

burned plots. Fertilization had no affect on 

height growth which is consistant with the findings of McKee and others (1986). 

Since burning reduced height growth but not 

diameter growth, it is assumed that in highly 

scorched trees carbohydrates stored over winter 

were used for needle production and some diameter 

growth, rather than stem elongation. Therefore, 

height growth may have been minimal during the 

first flush of buds and trees in burned plots 

lagged behind those in control plots. A close 

comparison of the number of flushes and the stem 

length between flushes of trees in burned and 

control plots would give better insight into the 

effect burning had on height growth, 

Even though some height growth was lost the year 

after burning, the loss was less than expected. 

In unfertilized plots, height growth was reduced 

by 33 percent in burned plots as compared to 

controls. In addition, competition among trees 

will be grealty reduced. Therefore, growth rates 

of individual trees can be expected to be greater 

in burned plots than in controls during future 

years. Close monitoring of tree growth and stand 

dynamics in these study plots over the next few 

years will provide a longer-term evaluation of 

prescribed fire for precommercial thinning, 

A comparison of backing, flanking , spot, and 

strip headf ires showed that each acted as a 

thinning from below with high mortality in small 

tree size classes. Backing fires provided the 

highest survival rates among the largest trees and 

the most uniform thinning throughout the study 

plot, Therefore, backing fires were chosen for 

continued study in this natural 4-year-old 

loblolly pine stand. 

A winter backing fire reduced the number of 

stems per acre from 6,800 to 2,850. The pattern 

of thinning was silviculturally desirable since 

the diameter and height size distribution was 

changed from a reverse-J to a bell-shaped pattern, 

Also, mean tree height and diameter were 

increased. Crown scorch was high throughout 

burned plots but needle consumption was infrequent. Mortality was most common among trees with 

at least 80 percent crown scorch and/or some 

degree of needle consumption. Burning improved 

the uniformity of stocking since understocked 

areas were esentially absent and overstocked areas 

were less frequent than before burning. However, 

almost half of the area remained overstocked. 

Diameter growth during the year after burning was 

not affected but height growth was reduced by 33 

percent (2.7 feet in control plots vs. 1-8 feet in 

burned plots). 

LITERATURE CITED 

Brown, A.A. and K.P. Davis. Forest fire control 

and use. New York: McGraw-Bill Book Co,; 1373. 

686 pp. 

Clark, P.J. and F.C. Evans. Distance to nearest 

neighbor as a measure of spatial relationships 

in populations, Ecology 35:445-453; 1954, 

Johansen, R.W. Prescribed burning may enhance 

growth of young slash pine. Journal of Forestry 

73:148-149; 1975. 

Johansen, R.W. Southern pine responses to 

aerially ignited prescribed burns. In: 

Proceedings of the 1983 Convention of the 

Society of American Foresters; 1983 October; 

Portland, OR; 1984:281-284, 

Johansen, R.W. and D.D. Wade. Response of slash 

pine stands to severe crown scorch. In: J.N, 

Long (ed,) Proceedings of Fire Management - The 

Challenge of Protection and Use; 1985 April; 

Logan UT; 1986:31-34. 

Langdon, 0.G. Natural regeneration of lobloily 

pine: A sound strategy for many landowners, 

Southern Journal of Applied Forestry 53170-176; 

1981. 

McCulley, R.D. Management of natural slash pine 

stands in the flatwoods of south Georgia and 

north Florida. U.S, Department of Agriculture 

Circular 845; 1950. 57 pp. 
NcKee, W.H., Jr.; R.W. McKleod; C.E, Davis; M,R, 

McKevlin; and H.A. Thomas. Growth response of 

loblolly pine (Pinus taeda L.) to municipal and 

industrial sewage sludge applied at four ages on 

Upper Coastal Plain sites, In: D.W. Cole (ed,) 

Proceedings of the Forest Land Applications 

Spposim; 1986 July; Seattle WA; (In press). 

McNab, N, An overcrowded loblolly pine stand 

thinned with fire. Southern Journal of Applied 

Forestry 1:24-26; 1977. 

Methven, J.R. Prescribed fire, crown scorch, and 

mortality: field and laboratory studies on red 

and white pine, Pinus taeda. Canadian Forest 

Service, Petawawa Forest Experiment Station, 

Report PS-X-31, 1971. 

Morris, W.G. and E.L. Mowat, Some effects of 

thinning a Ponderossa pine thicket with a 

prescribed fire. Journal of Forestry 

56: 203-209; 1958. 

Muraro, S.J. The use of prescribed fire in the 

management of lodgepole pine. In: Proceedings 

of Fire Ecology in Resource Management, Canada: 

1977 December; Edmonton, Alberta. 1978:82-89. 

Nickles, J.K.; C.G. Tauer; and J.F. Stritzke. Use 

of prescribed fire and hexazinone (Velpar) to 

thin understory shortleaf pine in an Oklahoma 

pine-hardwood stand. Southern Journal of Applied 

Forestry 5:124-127; 1981. 

Storey, T.G. and E.P. Merkel. Mortality in a 

longleaf-slash pine stand following a winter 

wildfire, Journal of Forestry 58:206-210; 1960, 

Thompson, H.R. Distribution to the nth nearest 

neighbor in a population of randomly distributed 

individuals. Ecology 37:391-394; 1956. 

Villarrubia, C.R. and J.L. Chambers. Fire: Its 

effects on growth and survival of loblolly pine, 

-- Pinus taeda. Louisiana Academy of Sciences 

4 1 : 85-93; 1978. 

Wade, D,D. Survival in young loblolly pine plantations following wildfire. 1N:Proceedings of 

the Eighth National Conference on Fire and 

Forest Meterology; 1985 April; Detroit, MI. 

1985:52-57. 

Waldrop, T.A. and D,H. Van Lear. Effect of crown 

scorch on survival and growth of young loblolly 

pine. Southern Journal of Applied Forestry 

8:35-40; 1984. 

Weaver, H. Fire - Nature's thinning agent in 

Ponderossa pine stands. Journal of Forestry 

45:437-444; 1947. 

Wooldredge, D.D. and B. Weaver, Some effects of 

thinning a Ponderossa pine thicket with a 

prescribed fire, TI. Journal of Forestry 

63:92-95; 1965. 

Roe, A.L.; W.R. Beaufait; L.J. Lyon; and J.L. 

Oltman. Fire and forestry in the Northern Rocky 

Mountains - A task report. Journal of Forestry 

69:464-470. 1971, 
RELATING WILDLAND FIRE TO DEFOLIATION AND MORTALITY IN PINE" 

Dale D. Wade and R. W, Johansen 2 

ABSTRACT,--Numerous accounts in the literature demonstrate 

that the effects of fire on North American pines are highly 

variable, In some cases trees with severe crown scorch survive 

and grow more rapidly, while in other cases extensive mortality 

results, Three of the most inportant factors affecting a 

tree's response to fire are the timing of defoliation, level of 

defoliation, and species differences in bud development, An 

ongoing field study designed to assess the importance sf 

defoliation level and timing upon southern pine survival and 

growth is described. 

The literature contains numerous accounts of 

fire and its effects on the pine forests of North 

America. This extensive data base spans a period 

of more than 100 years and ranges from simple 

recollections to replicated laboratory studies. 

The full range of plant responses to all but the 

most intense fires can be found. Differing 

responses to fire are caused by a host of 

factors, many of which are mentioned in Wade and 

Johansen (1986). We speculate that three of the 

most important factors affecting survival and 

subsequent growth are the timing of defoliation, 

level of defoliation, and species differences in 

bud development. These factors are discussed in 

this paper. In addition, an ongoing field study 

designed to assess the importance of defoliation 

upon southern pine survival and growth is 

outlined. Growth differences 3 months after 

defoliation and visual impressions 6 months after 

defoliation are described. 

BACKGROUND 

Plant tissue is killed when its lethal 

time-temperature combination is reached, A 

commonly accepted temperature for nearinstantaneous death is 140'~ (Byram 1948). 

Temperatures of 115'~ will also kill plant 

cells if they are sustained for several hours 

according to work reviewed by Hare ( 1961 ) and 

'paper presented at the Fourth Biennial 

Southern Silvicultural Research Conference, 

Atlanta, Georgia, November 4-6, 1986. 

*pro t Leader and Research Forester, 

respectively, Southeastern Forest Experiment 

Station, Southern Forest Fire Laboratory, Dry 

Branch, GA 31020. 

McRrthur (1980), but prescribed burns are not 

likely to elevate temperatures for that long a 

period. Yellow to bronze foliage irnnediately 

after a fire is a sure indicator that a lethal 

heat dose was applied; the discolored needles 

are in fact dead, Charred or partially consumed 

needles indicate that the ignition temperature of 

cellulose (about 450' F) was reached. These 

mortality and ignition thresholds are 

increasingly likely to be met as the ambient air 

temperature increases. Summer fires oEten occur 

when ambient temperatures are 30 to 60 F higher 

than those associated with winter fires. 

Moreover, temperatures of the upper tree crowns 

can be higher than the surrounding air due to 

solar heating. Thus, little additional heat is 

required to raise needles to their lethal 

temperature threshold during summer burns. 

Even with cool winter temperatures, southern 

pines can suffer complete crown scorch, but they 

also routinely survive provided they are larger 

than about 2 inches d.b.h. and no foliage is 

actually consumed, Crown damage from fires 

during the growing season is generally more 

severe, and its consequences are more serious. 

We believe this differential survival between 

seasons is primarily a function of bud-kill. 

When bud-kill is combined with defoliation, a 

much more life-threatening situation exists. 

Crown scorch does not automatically signify 

bud-kill in the four major southern pine species 

because the buds of these species, especially 

longleaf (Pinus palustris Mill.), are thicker 

than the needles, Because the rate of 

temperature rise is inversely proportional to 

thickness, either higher temperatures or lower 

sustained temperatures are necessary to kill the 

buds of such speeies. There are no obvious signs 

to enable an observer on the ground to 

differentiate between completely scorched trees 

with and without bud damage if needles have not 

been consumed, 
For species with needles at least equal to 

their buds in thickness, crown scorch is a 

reliable indicator of crown kill, These species 

also tend do have fine branches which are easily 

heat-killed, even though the branch tips may 

temporarily survive because the needle clusters 

form a protective sheath around them. Regardless 

of the protective mechanism, a given tree is much 

more likely to suffer crown damwe during a 

r fire because of higher ambient 

temperatures. 

BUB DEVELOPFfENT Am TIMING OF DEFOLIATION 

Most northern temperate zone pines have 

preformed buds, That is, their winter buds 

contain all the unexpanded shoots for the 

following season" growth. These species are 

thus confined to a single growth flush each 

year. After dormancy is broken in the spring, 

the shoots elongate fairly rapidly (1 to 2 

months) and then form next year" buds. 

The four major southern pine species, on the 

other hand, undergo multiple flushes because 

their winter buds do not contain all the shoot 

primordia for the following growing season. When 

dormancy is broken in the spring, the terminal 

bud expands into a shoot and a second bud forms 

at the apex of the shoot. That bud elongates to 

extend the initial shoot, and another bud is 

formed. Southern pines generally undergo three 

to four flushes during the growing season 

although as many as seven have been recorded in 

the literature (Vdeley and Marreso 1958). 

Depending upae species and environmental 

conditions, the buds that form after the first 

flush may open imediately upon formation or 

after varying periods of time (Romberger 1963). 

Defoliation, especially early in the growing 

season, has been shown to stimulate the rapid 

opening of buds regardless of whether the species 

has preformed buds or is multinodal. Later in 

the summer, however, defoliation will not elicit 

the same response--apparently due to a shortening 

of the photoperiod, so the defoliated tree 

remains naked until the following spring. 

Complete defoliation of any evergreen has 

dire consequences with damage a function of the 

length of time the tree is without foliage. It 

has been demonstrated that root system recovery 

after defoliation is directly related to the 

length of time the trees are defoliated. 

Kozlowski (1971) presents a synopsis of the 

evidence that shows root growth is governed by 

the supply of photosynthetic products and growthregulating hormnes from the crown. The 

reduction in live root mass following severe 

insect defoliation is well documented (Swain and 

Craighead 1924, Redmond 1959, Gregory and Wargo 

1986). However published data rebating fire 

defoliation to ((rau&h responses ad mortality 

are, at first glance, without pattern and in some 

instances appear ts be contradictory. Separation 

of this literature by season of defoliation and 

bud development markedly clarifies the picture. 

In species with preset buds, complete defoliation 

any time during the growing season will result in 

death (e.g. Craighead 1940, OtNeil 1962, Metbven 

1971), while in the multinodai southern pines, 

the danwe is most severe following defoliation 

late in the growing season (Allen 1960, Beal 

1942, Bruce 3 956, Wade and Ward 4 975) , 

FIELD STUBY 

In an attempt to determine the importance of 

season and level of defoliation and to assess Lhe 

magnitude and duration of any growth responses in 

southern pine, we installed a defoliation study 

in 4-year-old loblolly pine (P. taeda L.) and 

slash pine (P, elliottii Engelm.) plantations. A 

factorial experiment (4x5) with a random mixed 

block design was established at 4 locations (2 

per species), Fifteen blocks were used at each 

location. One of five levels of defoliation (0, 

33, 66, 95, or 100 percent) and one of four 

seasons of defoliation (January, April, July, or 

October) were assigned to each of 20 trees within 

a block, Needles were hand removed during the 

first 2 weeks of each treatment month. 

Pretreatment d.b.h, and height were measured 

on all 1200 trees during the 1985-86 dormant 

season. The April, July, and October defoliation 

took place as scheduled, While applying the 

October treatments, we formed several visual 

impressions regarding the trees defoliated 

earlier in the growing season. Those trees 

defoliated 6 months previously (April) had all 

refoliated, undergone several flushes, and looked 

healthy, The trees defoliated in July, on the 

other hand, had all refoliated but had not 

undergone as many post-defoliation flushes and, 

thus, had sparser crowns, Tn many instances the 

needles on the July trees also appeased to be 

somewhat chlorotic, 

Heights and d.b,h.*s of the trees defoliated 

in April were remeasured in July. Growth 

differences between defoliation levels are 

striking (Table 1). Three-nonth diameter growth 

was commensurate with the level of defoliatidn, 

Diameter growth of the coaapletehy defoliated 

trees was 34 and 36 percent of the non-defoliated 

trees for loblobly and slash pine, ~esgeetively, 

The same general trend was found in height 

growth, though species differences were greater-- 

62 percent in slash pine and 45 percent in 

loblolly pine. la three of the four locations, 

trees that had the lower 33 percent of their 

crowns removed outgrew the controls in height 

during the first half sf' the growing season, Ail 

trees are scheduled for remeasurement during the 

3986-87 and 7987-88 dormant seasons, 
Table 1.--Three-month growth responses of southern pine subjected to five 

levels of defoliation during early April 1986. 

I I 

I DBH t Height 

Location f Percent Defoliation I Percent Defoliation 

Slash pine f I 

GA For, Comm, f 100 100 73 43 46 1 100 99 85 79 63 

Waycross, GA I I 

I I 1- -- I -- I 

Slash pine f I 

Union Camp Corp. 1 100 82 44 35 26 f 100 100 99 67 6 1 

Palatka,FL f I 

Loblolly pine f I 

Int. Paper Co, 1 100 79 70 47 34 1 100 100 94 67 5 3 

Bainbridge, GA f I 

1 I 

8- I t 

Loblolly pine I t 

Westvaco Corp. f 100 82 65 40 32 1 700 102 77 59 3 8 

Branchville, SC I t 

1 t 

'~xpressed as a percentage of the growth of trees with no defoliation. 

All study trees, including those completely 

defoliated at the beginning of the growing season 

or halfway through the season, had refoliated and 

were alive as of early October, However, both 

diameter and height growth had been severely 

retarded, especially with the more severe levels 

of defoliation. At this time we can only 

speculate on future growth losses or mortality, 

although some of the July defoliated trees show 

signs of trauma in the forn of yellowing in the 

new-growth needles. When the full impact of 

these crown damage treatnents has been assessed, 

the results will have obvious implications in the 

scheduling of prescribed fire as well as in 

interpreting literature reports on nfire 

treatmentn used to measure fire effects. 

LITERATURE CITED 

Allen, Peter H. 1960. Scorch and mortality after 

a sunner burn in loblolly pine. Res. Note 

SE-144. Asheville, NC: U. S. Department of 

Agriculture, Forest Service, Franklin Research 

Center. 2 pp. 

Beal, J.A. 1942. Mortality of reproduction 

defoliated by the Red-headed Pine Sawfly 

(tJeodiprion lecontei Fitch). Journal of 

Forestry 40(7):562-563. 

Bruce, David. 1956. Effect of defoliation on 

growth of longleaf pine seedlings, Forest 

Science 2(1):31-35. 

Byram, George M, 1948. Vegetation temperature and 

fire darnage in the southern pines. Fire 

Control Notes 9(4):34-36. 

Craighead, F.C. 1940. Sone effects of artificial 

defoliation on pine and larch. Journal of 

Forestry 38( 19 ) : 885-888. 

Gregory, Robert A. and Philip M. Wargo, 1986. 

Timing of defoliation and its effect on bud 

development, starch reserves, and sap sugar 

concentration in sugar maple. Canadian Journal 

of Forestry Research 16(1):10-17. 

Hare, Robert C. 1961. Heat effects on living 

plants. Occas. Pap, 183, Mew Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station. 32 pp. 

Kozlowski, T.T. 1971. Growth and development of 

trees. vol. 2., chapter 5, Mew York: Academic 

Press. pp. 196-250. 

McArthur, Geoffrey Elorrison, 1980. Prediction of 

crown scorch in Pacific Morthwest underburns. 

Seattle: University of Washington. 175 pp. 

Thesis, 
Methven, Ian R, 1971. Prescribed fire, crown 

scorch and mortality: field and laboratory 

studies on red and white pine. Chalk River, 

Ontario Info. Rep. PS-X-31, Department of the 

Environment, Canadian Forestry Service, 

Petawawa Forest Experiment Station, 10 pp. 

OWeil, L,C, 1962, Some effects of artificial 

defoliation on the growth of jack pine (Pinus 

Banksiana Lamb.) Canadian Journal of Botany 

46(2) : 273-280. 

Redmond, D.R. 1959. Nortality of rootlets in 

balsam fir defoliated by the spruce budworm. 

Forest Science 5( 1 ) : 64-69. 

Romberger, J.A. 1963, Meristens, growth, and 

development in woody plants. Beltsville, MD: 

Tech. Bull. 1293, U.S. Department of 

Agriculture, Forest Service, Plant Industry 

Station. 214 pp. 

Swaine, J.M. and F.C. Craighead. 1924, Studies on 

the spruce budworm (Cacoecia Fumiferana Clem.) 

Part 1. A general account of the outbreaks, 

injury and associated insects. Tech, Bull. 37. 

Dominion of Canada, Department of Agriculture. 

91 PP* 

Wade, Dale D. and R.W. Johansen, 1986. Effects of 

fire on southern pine: observations and 

recomendations, Gen. Tech. Rep, SE-41. 

Asheville, NC: U.S. Department of Agriculture, 

Forest Service, Southeaqtern Forest Experiment 

Station, 14pp. 

Wade, Dale D. and Darold E. Ward. 1975. 

Nanwement decisions in severely damaged 

stands. Journal of Forestry 73(9):573-577. 

Wakeley, Philip C, and Joseg Marrero. 1958. 

Five-year intercept as site index in southern 

pine plantations. Journal of Forestry 

56(5):332-337. 
Hardwood Regeneration 

Moderator: 

J.S. McKnight, Forestry Consultant 

Stone Mountain, Georgia 

ION OF APPALAGWfAN 

E. Blount, James E. Cook, David Win. Smith, 

Terry L. sharikU - - - - -- 

Abstract. Stand mmsition and structure are evaluated in nine SppdLachian 

oak stands along a topographic misture gradient seven years after clear 

felling. Site index ranged from 37 to 71 (base age 50 for upland oaks) . Seven 

years after harvest, the number of well-established oak stm of advanced 

regeneration origin was larger in stands of site index 55-65 and smaller in 

sites of higher and lower quality. An accelerated rate of canow closure 

occurred with increasing site quality, and stump sprouts were substantially 

taller than seedling sprouts or advanced regeneration. The abundance of various 

types of oak regeneration varied with site quality. Canopy closure has occurred 

on the medium- and higher-quality sites. Low-quality sites are poorly stocked, 

and oak sprouts remain mltiple-std in apparance because of little 

competition from the sides. Pines have begun to seed in the open areas, but due 

to their low numbers it appears that oaks will dominate the sites. Quantitative 

results characterizing stand composition and structure are presented. 

The deeply dissected terrain of the Ridge and 

Valley Physiographic Province of Virginia 

exhibits large variations in site quality. 

Associated with these changes in site quality 

are noticeable changes in overstory and 

understory composition in 60-to 80-year-old 

second growth forests (McEvoy et al. 1980). 

Variation in conposition and growth across 

sites should also be evident following 

disturbance, reflecting the differences in site 

characteristics (amount of litter, radiation, 

etc.) and/or site potential. 

The Ridge and Valley is characterized by a 

series of northeast to southwest tending ridges 

separated by wide valleys. The midslope 

positions on southeastern exposures are 

dominated by various mixtures of chestnut oak 

L.), scar 

lack oak 

(Braun 1950; Whittaker 1956; Day and Monk 1977; 

McEvoy et al. 1980). The proportions of these 

species vary with changes in site quality 

(Braun 1950; Whittaker 1956; McEvoy et al. 

1980) . Ch the drier south-to-southwest facing 

haper presented at Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, IiJov?ntber 4-6, 1986. 

Grad. Res. Asst., Grad. Re. Asst., 

Prof., Dept. of Forestry, Virginia Polytechnic 

Institute and State Univ., Rlacksburg, VA; 

Assoc. Prof,, Dqk. of Forestry, Michigan Tech 

University, Houghton, MI. 

ridges and slopes, pitch pine ( 

Mill.) and Table Mountain pine 

lAb. increase in n-er while black oak 

decreases. 

There is a significant acreage dominated by 

poor quality upland hardwoods, and there 

appears to be potential to inprove both the 

quality and quantity of stems following 

clearcutting. Several studies have quantified 

the effects of harvesting on upland hardwood 

sites (Lamson 1976, Mann 1984, Mae 1980). The 

objective of this study was to quantify canow 

developanent and species composition across site 

qualities in Appalachian upland hardwood stands 

7 years after clearcutting. The present study 

is part of a long term project initiated in 

1977 by Virginia Polytechnic Institute and 

State University in coopration with the U.S. 

Forest Service to study the effects of 

whole-tree harvesting on upland hardwood 

stands. 

The study is located at a midslope position 

on the southeast slope of mtts Mountain in 

Craig County, Virginia. The approximate 

elevation is 2500 feet, and slopes average 30 

to 40 percent. Parent materials are nutrient 

poor sandstones and shales and usually give 

rise to coarse-textured, stnallow, and strongly 

leached soils (Norin 1978). Annual 

precipitation is 38 inch- and is evenly 

distributed throughout the year. The 

frost-free growing season is approximately 160 

days. The range in site quality is from S 

37 to SI 71 for upland oaks. All site in k 

referend8 refer to that of upland oaks at base 

SEJDY AREA 
ed from the curves of Olson 

(1 959) , 

The study sites were characterized by the 

study sites *re charaderized by the overstory 

species mix as well as the quantity and 

cowsition of the understoq. Four distinct 

vegetation re delineated --- mix e, 

mixed oak-p ed oak, and mixed ha 

(McEVoy et ale 1980) , Ross (1982a) app 

separate productivity indicies to the 

vegetation types and found a gradient of 

increasing growth potential in the order mixed * ec-i oak-pine, mixed oak, and mixed , Meiners (1981) found the 

productivity grdient to be closely related to 

soil moisture during the growing season. 

The mixed pine site, SI 37, is 

characterized by an overs28ry dominated by pine 

with a few oaks scattered throughout (McEvoy et 

al. 1980). A dense shrub layer dominated by 

ericads and bear oak ( Wang.) is 

also present, The mix ite, SI 49 

upland oak, has an overstory predominated 8y oak with a few scattered pines. The 

well-developed 

muntain lm 

ericaceous understory, The mixed hardwood 

site, SI 71, is dornhated by mre mesic 

species 28ch as red maple (Acer rubrurn L.) 

yellow-poplar ( 

black locust ( 

shrub stratum is poorly developed, but the herb 

layer is well-reprsented. 

Nine 0.40 acre plots were established in the 

fall of 1977 and the spring of 1978. The plots were located along a 3.3 mile midslope road in 

3 nonwntiguous cutting units totalling 150.7 acres. The nmber of plots for each vegetation 

type varies: mixed pine, 3 plots; mixed 

oak-pine, 1 plot; mix& oak, 3 plots; mixed 

hardwood, 1 plot; and one wntrol (uncut) plot. 

Prior to harvest a mrrp?lete vegetation 

inventory was made. Three strata were established bad on vertical plant height: 

herb stratm -dl stems less than 3.3 feet in 

height, shrub stratum - mcxfy stans between 3.3 

and 16,4 feet in height, and the tree stratum 

y st- greater than 16.4 feet in height. 

Between liugust 1978 and March 1979, all stems 

M.9 feet in height were cut back to within 5.9 

inches of ground level and rmved from the 

plot. AL1 suitable materid was rerru3ved from 

the sites as part of a rcial whole-tree 

harvesting operation, One mixed oak plot was harvested during Puagust, whereas all others were harvested duri,~g the dormant season. Stump 

sprouts occurred .in Sept&er and October on 

the plot harvested durw the cgrowbg season, 

but all sprouts were killed by frost before 

winter. 

Since harvest, changes in the vqetation 

vegetation cowsition and structure have ken 

docummted by repeated hventories. Tree 

ts were carried out in March 

and April of each year (through 1986) itnd all 

stems greater than 16.4 feet in height were recorded by species, total height, and dbh. A 

metal identification tag was attached to each 

tree in this stratum at approximately 5.9 

inches above the forest floor, 

Due to the lack o ement ptmtial in 

the two lower quali 

the information for these plots was 1 

together and reported as sites with SI (50. 

In the spring of 1986, shrub stratum 

measurements for the seventh growing season were taken. The shrub stratsun inventolry was a 25 percent sample consisting of 16 randomly 

chosen subplots (each subplot contabs 269 ft 

within each of four plots, These plots 

represented all four vegetation types 

delineated by McEvoy et al , (3980) . All stans 

between 3.3 feet and 16.4 feet in height were recorded by species, total height, ant% diameter 

at 5.9 inches, 

In the preharvest stands, as site index 

increased, therq was an increase in tree Lpal area from 90 ft /acre on SI (50 to 120 ft /acre 

at SI 70 (Table 1) (McEvoy et &. , 19801 . The 

greatest density war; also found on the highest 

quality site. In the shrub stratm, an increase in site quality resulted in a decrease 

in basal area and shrub dmsitz. Shrub basal area was 19.8, 5.2, and 4.8 ft //acre for SI 

(50, SI 60, and SI 70, rsptively. Average 

shrub height was substantially higher on SI 70. 

These trends in basal area and shrub density 

agree with the reports of mittaker and 

FJoodwell (1969) for oak-pine forests at 

Brookhaven, blew Uork. 

S m DISCUSSION 

Ross et al. (1986) descraed the oak; 

regeneration on the Potts Mountah study sites 

2 years after hamest. They concluded that 

chestnut oak sprouted mre freguently and grew more rapidly than both scarlet md black oak. 

In general, both stump sprouts and advanced 

regeneration increasd in height with 

increasing site quality, The dasity of oak 

advanced regeneration was greatet on SI 55-65 

and decreased on sites of higher and lowr 

quality. 
Table l. Prehanrest st& s 

tree stratum (all stems >16.4 ft, in height) 

and the shrub stratm (all st- kt*= 3.3 

and 16 .4 ft. in height) by site index (upland 

oaks, base age 50 (Olson 1959)), western 

Virginia (McEv;oy 1978) . 

density 3833 1479 935 

(Wac) 

average ht. 5.6 5.3 8.2 

(ft) 

: BBl.1 area measure3 at dbh Basal area' measureil 5.9 inches above the forest floor 

Recruitment into the tree stratum did not 

begin until the fourth growing season (Table 

2). During the fourth and fifth year black 

locust was cleanly the most comn species in 

the tree stratum. In year 6, chestnut oak and 

black locust were equally represented, followed 

in decreasing order by red maple and Arnercian 

chestnut ( (Marsh. Borkh. . During the seventh growing season, chestnut oak 

became the dominant species followed by black 

locust, red maple, &rim chestnut, and 

scarlet oak, in decreasing order of abundme. 

The basal area at gear 7, averaged across all 

sites, was 4.50 ft /acre, 

The harMod forests of the Ridge and Valley 

originally contained a large component of 

American chestnut (Brw, 1950). Loss of the 

f 

other stem, and, to a lesser extent, on the 

coesition of these stands (Nelson 1955) . Chestnut continues to resprout from the 

original stumps and stem. Our data and 

observations indicate that the early growth and 

form of &rican chestnut is better than all 

other species, especially on the drier end of 

the spectrum. If an effective and economical 

method of inoculating chestnut sterns to prevent or cure the blight is developed in the near future, chestnut in recently cutover stands 

might once again bmm a major conapnent of 

these forests. 

The tree stratum density is increasing on all sites (Figure If; bwever, recrui 

occurring at the fastest rate on Sf 70, with a lower rate on SI 60 and SI (50 sites, 

respectively. The poorest site qualities are developing slowly with only 48 stemslacre at 

year 7 compared to 980 sterns/acre on the 

highest quality site. 

The species cowsition of the tree stratum 

also varies across site qudities (Figure 2). 

With an increase in sike quality there is an increase in species diversity in the tree 

stratum. Areas with SI (50 are dominated 

dlrrr>st entirely by oaks at year 7. Site index 

60 sites are dominated by oaks and black 

locust, and SI 70 sites are dominated by red 

lack locust, sassafras ( 

(Nutt.) Nees) , ye110 

oaks, in order of decreasing density. Tree 

stratum basal area also increases with an increase in site quality (Table 312 At age 7 

the basal area ranges fr2m 0.97 ft /acre on the 

poorest site to 15.70 ft /acre on the best 

site. 

On all sites, chestnut oak was the tallest 

and mst abundant oak in the tree stratum, 

followed by scarlet and black oak. Dn areas with SI (50 the average diameter of scarlet oak was greater than chestnut oak or black oak: 

2.1, 1.9, and 1.7 inches, respectively. 

However, on the intermediate sites the average 

diameter for scarlet oak and black oak were equal and they exceeded chestnut oak by 0.3 

inches (2.0 vs. 1.7 inches). Ch the mesic site 

(SI 70) chestnut oak was the only oak present 

in the tree stratum. All oaks presently 

occupying the tree stratum originated from 

stump sprouts, 

A knowledge of the shrub stratum composition 

is needed in order to properly evaluate the 

tree stratum composition and how it will 

develop in the future. The density and basal area of the shrub stratum varies by site 

quality (Table 4). The major differences are the much larger values for the mixed oak site 

(SI 601, as compared to the other two; ie. 

20,204, 6781, and 6464 stems/acre on sites SI's 

60, <so, and 70 respectively, The sites of SI 

<50 and 70 have aproxhtely equal densities 

(35.9 vs. 29.8 ft /acre), with she SI 70 site 

having mre basal area (65.6 ft lacre). In 

contrast with these trends, stratum height 

increased from the xeric to mesic sites. 
Table 2, Density and basal area s for the tree Stratum (all 

st- >16.4 ft. in height) for the entire Btts sin study area* Average 

heights are given for seven-year~ld trees. The area was wholetree harvested 

during the fall and winter of 1978-79. 

Y' WJ STEMS Bfe SIEMS 9 STEW Bg AVGHP 

(#/ad (ft fat) (Cfac) (ft lac) (#/acscf (ft lac) (#/ad (ft /ac) (I/acf (ft /w) fft) SPmw 

C31ee-t oak - - 1 <0.10 8 0.15 35 0.63 85 1.66 18.7 

Scarlet oak - - - - - - 1 (0.10 11 0.24 17.7 

Total - - 6 0.10 46 0.75 118 1.93 250 4.50 19.1 

Mher includes black oak, swrwood, blackgum, yellmepoplar, sassafras, wit&-hazel, mockernut. 

AGE 

60 70 

SITE INDEX 

Figure 1. Tree stratum density (all stw 

>16,4 ft, in height) by age and site index 

(base age 50, upland oaks (Olson (195911, 

s, western Virginia. 

POPLAR 

@ MAPLE 

LOCUST 

@ OAKS 

@ OTHER 

Figure 2. ,Seven year upland hardwood tree 

stratum densities (all sterns >16.4 ft. in 

height) by species and site index (base age 50, 

upland oaks (Olson 195911, seven-year upland 

hardwood stands, western Virginia, 
mLe 3, ity ad hal area s 

the tree ~"catum kill stew >16,4 ft,) of seva year OM upland ha 

(base age 50, upland oaks (Ohon 3959) ) , western Virginia, 

(50 Ws 46 0.93 

American chwtnut 1 0.02 

Sou I-k. -AM.& 

"i'ota.I.8 48 0.97 

60 Oaks 174 2.67 

Black locust 52 1.15 

mricm chesbutt 19 0.30 

Red mple 1 0 .O1 

Other 

%t&s & 4.36 

70 Red mple 374 5.56 

Black locust 235 4.98 

Chestnut oak 76 1.36 

Sassafras 121 1.34 

mlip poplar 84 1.12 

Other 

Tbtals 

22fL 

980 

X 

15.70 

' Baal area =dsun& at dbh. 

ries of density, average height, 

and basal area for the shrub stratum (all stems 

between 3.3 and 16.4 feet in height) under seven year old upland hardmod stands by site 

index (base age 50, upland oaks (OLson (1959) 1, 

western Virginia, 

SITE IlUDM STEMS 

(#/ad (ft) 

'ma1 area measured at 5.9 inches above 

forest floor 

Many of the plants presently growing in the 

shrub stratum will eventually mve into the 

tree stratum. Figure 3 shows the nmber of 

sterns by spies for each site quality that are present in the tree stratwn at 7 years,,plus 

those which have the potential to move unto the 

tree stratum. Selection of possible recruits 

was on the basis of growth form, A brief 

discussion of the composition and probable 

% of each site follows. 

Site Index <SO 

The shrub stratum on low qtzality sites is 

by saseras, blackgum ( 

rsh.), oaks, and red mpl 

is mre abundant than chatnut oak. 

Our data show that the majority of the oak 

stems present in the shrub stratrum are stwnp 

ite quality it is 

e, blackgum, or sassafras will becorn part. of the dohant 

canopy, Beeause only 40 pine stmlacre are present, it appears that these lower quality 

sites will be dominated by oaks i-2 the future. 

Site inds 60 

The shrub stram is presently dominated by 

sassafras, oaks, blackgum, mapleearad hickory, 

in order of decreming abundance. The large 

t of sassafras following disturbance 

of many pioneer species, These 

species colonize it1 high nwers b&iately 

after disturbance, but die out quickly (Marks 

and Born 1972, bss et al. 1982b). 

Therefore, sassafras is not expected to be a significant covnent of the canopy. However, 

it may play a vital role in the mintmance of 

site quality. Preharvet data indicated 

sassafras tissues were consistently 

above-average in nitrogen, pbsp;homs, and 

potassium concentrations (Martin et al. 1982). 

Pioneer species can be rtant in areducing 

nutrient losses from t te by functioning as a nutrient sink following canopy rmval or similar disturbance (Marks and Bo 1972; 

Boring et al, 1981) . The tree stratum on these sites is currently 

dominated by oaks and black locust, The large 

number of oaks present in the shrub stratum - mainly advance regeneration - indicates that 

the site will continue to be dominated by oaks. 

However, black lwust will also be a major 

conlponent. Although there are only 61 black 

locust sterns/acre in the shrub stratum, mst 

of these are near the upper limit of the 

stratum height and thus have a high probability 

of making it into the canopy, 

Site Index 70 

Both the prehawest and the 7-year 

postharvest tree strata oontained a greater 

diversity than that which was found on lower 

site qualities. The tree stratum is currently 

dominated by red maple, black locust, 

sassafras, yellowpplar, and oaks, in 

decreasing order of abmdance; whereas the 

shrub stratum is dominated by sassafras, red 

maple, blackgum, yellowpplar, black locust, 

and oaks. Although the sassafras and blxkgm are growing faster on this site than on the 

others, it is doubtful that they will maintain 

their ds~ance. First, they are below the 

level of the domhant red maple, black loeust, 
TREE 

p$ c,iiF;L!p Am 

qite index 69 

a TPEE 

@ S..'lbB 

2ooo 1 Site index 70 

(b) SPECIES 

a TREE 

SHRUB 

(c> SPECIES 

Figure 3. er of stems by species that are 

presmt in the tree stratum (all stems >16,4 

ft, in height) plus those stems which have the 

ptential to mve from the shrub stratum (all 

sterns between 3.3 and 16.4 ft, in height) into 

the tree stratum. Selection of possible 

recruits was on the basis of growth form, Data 

are scunmaries after seven growing seasons in 

upland oak stands with site index (50 (a), site 

index 60 (bl, site index 70 (c), (base age 50, 

(Olson 1959) 1 in western Virginia. 

and yellow-poplar. Md secsndly, sm&ras is 

a short-lived spies as evide~ceCI by its lack 

of presence in the preharvest mow. 

Therefore, the mature forest eanopy will 

probably be a mixture of red maple, black 

locust, yellow-poplar, arid oak with sas&ras 

and blackgum scattered througbut. 

The Ridge and Valley Physiogrqhic Province 

of sout-tern Virginia is a deeply dissected 

region that contains a wide range of site 

qualities. Because substantid site quality 

variations can occur in a few hundred feet, it 

is wrtant for the forest manager to realize 

the effects this variation in site quality has 

on the composition and growth of hardwood 

stands following harvest. 

stands of site index 

e oaks into the tree 

during the first 7 years, 

hrub stratum will 

continue to occur but at a very slow rate. 

When the rider of potential crop trees is 

calculated (taking into account sprout clumps) 

and the lack of cowtition from the side (to 

produce reasonably straight stem) are 
consider& (Ross et al. 19861, it is apmrent 

that prctduction of usable 

low, Thus it appars that 

could be a cutoff for active 

t for ti&r production. 

wand hardmd stands with site indices 

b 50 and 70 are heavily stocked with oak r tion and the future stand will probably 

b at& by oaks. 

The most msic stand on these slopes, SI 2 

70, is currently dominatd by red maple and 

black locust; the oaks are a relatively minor 

comnent. Gompared to the other sites, the 

tree stratum is mre diverse. Some species 

will decline very soon (e.9, sassaEras1 or within the next 30-40 years, (egg. black 

locust). However, a nunber of other species 

(yellow-poplar, sourwood, hickory, sweet birch) 

have sufficient longevity to be present for 

50-100 years or longer. Therefore, the oak 

coqnent will probably remain a distant third 

to red maple and yellow-poplar with the 

miscellaneous species approximtely equal to 

the oaks in iprtance. 

Boring, L. R., C, D, Monk, and W. T. Swank. 

Early regeneration of a clear-cut southern 

Appalachian forest. Ecology 62: 1244-53. 1981. 

Brawl, E. L. 1950. Deciduous forests of eastern 

Nbrth America, Hafiner Publishing Company, New 

York. 596 pp. 

Day, F. P., Jr, and C. D. Monk, Net primary 

production and phenology on a southern 

Apwlachian watershed. American Journal of 

Botany 64: 1117-25. 1977. 

on, N. I. Appalachian ha 

sprouts are potential sawlog crop trees. U.S. 

Deprent of Agriculture, Forest Service, 

Mrtheastern Forest Experiment Station Research 

Note NE-229; 1976, 4 pp, 

K. First year regeneration in upland 

s after 2 levels of residue removal. 

Candim Journal of Forest Research 14: 

336-342, 1984. 

Marks, P. L., and F, H. Bo 

following forest cutting: 

return of steady-state nutrient cycling. 

Science 176: 914-915, 1972, 

Meiners, T. M., D, Wm. mith, T, L, Sharik, and 

D. E. Beck. Soil i3nd plant mter stress in an 

achian oak forest in relation to 

topoqraphy and stand age, Plant mi! Soif 

80: 171-179. 1984. 

MGEvoy, T. J,, T. L, Sharik, and D. hms, Smith. 

Vegetative structure of an Appalachian oak 

forest in southest Virginia, The iWricm 

Midlclnd Naturalist l03fl): 96-105, 1980, 

r4cGee, C. E. ions for 

reforestation rland Plateau, 

Southern Journal of Applied Forestry 4:158- 

162. 1980. 

Norin, R. A. Estimates of soil nutrient status 

of low quality har -pine sites of the Xdge 

and Valley area of Vi-rginia. MS. !l%esis, 

Department of Forestry, VPI&SU, Black&urg, Va. 

50 pp. 1978. 

Nelson, T. C. Chestnut replacment in the 

southern Highlands. Ecology 36: 352-53. 1955. 

Olson, D. J., Jr. Site index curves for upland 

oak in the southeast. U.S. Department of 

Agriculture, Forest Service, Southewtern 

Forest Exgeriment Station Research Mte; SE-125 

1959. 2 pp. 

P~ss, M. S,, T. L, Sharik, and D. Wm. Smith, 

Species and site relationships mng oak 

regeneration types after clearcutting in the 

Virginia Ridge and Valley. a: E, P. Jones, 

Jr. (Ed.). Proceedhgs of the Smnd Bictnnial 

Southern Silvicultural Research Conferace. 

USDA Forest Service General Twhnical Report 

SE-24, Asheville, E, pp. 151-2-56. 1982a, 

Age structure relationships of tree 

lachian oak forest in 

southwest Virginia. Bulletin of the Wrrey 

Botanical Club 109: 287-98, 1982b. 

- . Oak regeneration after clear-felling in 

southwest Virginia. Forest Science 32: 157-69. 

1986. 

Whittaker, R. H. Vegetation of the Great 

Smky Elountains. Ecological Wnographs 26:l80, 1956. 

Whittaker, R. N., Woctdwell, G, M, Structure, 

production, and diversity of the oak-pine 

forests of Brookhaven, Mew ?lark, Journill of 

Eeolog~ 57: 155-174. 1963, 

Hartin, W, L., T. L, Siaarik, and D, Wm. ,Smith. 

s and nutrient levels in the understory 

of an Appalachian oak forest in southwest 

Virginia, Bulletin of the Torrey Botanical Club 

109: 330-343, 1982, 
3EGROWrIl AF'f'ER CO!PLETE HARVEST OF A YCUXG 3Vr'I"0',7,A!13 f!A"nL'Y'JOD ST AN^" 

" / 

John K. Francis= 

Abstract.--An 11-year-old bottomland hardwood stand growing on poorly 

drained clay soil on the Mississippi River floodplain was harvested to 

determine yield and composition of the regrowth. Green ash made up 82% of 

the stems in the parent stand but comprised only 29% of the stems in the new 

stand 4 years after coppicing. Green ash was present in all plots, however, 

and produced the tallest stem in 81% of the plots, Ccdar and American elm 

accounted for most of the remaining tree stems. Although bottomland oaks 

comprised a small proportion of the stems in the 11-year-old stand, they 

were widely distributed and coppiced vigorously. Dry woody biomass iii year 

4 reached 15 t/ha for an average annual yield of 3.7 t/ha. In year 1, yield 

of herbaceous plants (3.5 t/ha) was nearly as great as yield of woody 

species (5 t/ha), but declined to almost nothing in year 4. Cue to the 

simultaneous decrease of herbs and the increase of woody species, total 

nutrient content in summer biomass changed little from year to year over the 

4 years of monitoring. It appears that if the coppice stand is allowed to 

mature, it will contain significant proportions of ash, elms, and oaks. 

INTRODUCTION 

Future industrial processes may routinely 

accept heterogeneous biomass for the production 

of fiber, chemical, or biological products. 

Because young stands are more adaptable to mobile 

continuous flow harvesting equipment, they may 

eventually be a preferred source of biomass. The 

use of young stands was envisioned a number of 

years ago (McAlpine and others 1966), extensively 

studied, and used to a limited extent (Mattson 

and Winsauer 1985). While plantations may be 

grown specifically for biomass, in the real world 

of forest industry expensive plantations will not 

be extensively established while abundant natural 

stands remain unexploited. 

Sefore complete harvest of young bottomland 

hardwood stands begins, foresters should have a 

good idea of what will grow to replace these 

stands and how the regrowth will develop. Also 

of concern is whether future productivity will be 

impaired by harvest of young stands. 

In an earlier publication (Francis 1984), I 

described the yield and nutrient content of the 

young stand that was harvested to produce the 

regrowth discussed in this paper. Others have 

studied yields from harvests of sapling stands 

(Hitchcock 1979, Krinard and Johnson 1931). 

However, the effects of the harvest of sapling 

stands on the composition of regrowth are 

generally unknown, Regrowth of young upland 

southern hardwood stands after fire was 

documented by )IcGee (1980). In that study, the 

number of doninant red maple (Acer rubrum) 

increased while the competitiv~ position of the 

oaks (Quercus spp. ) , yel1o.i:-;:o?lar (Liriodendron 

tulipifera), black cherry (a3run~t~ serotina), and 

white ash (Fraxinus americana) remained about the 

same. 

Methods 

The stand selected for this study was located 

near Stoneville, MS. The original stand had been 

a tract of mature bottomland hardwoods prior to 

clearcutting in 1969. The main tree species 

present at clearcutting were: Nuttall oak 

(Quercus nuttallii), willow oak (9. phellos), 

overcup oak a. lyratd), sweetgum (Liquidambar 

styraciflug), American elm (iilmus americana), 

sugarberry (Celtis laevigata), and green ash 

(Fraxinus pennsylvanica). 

Most of the regeneration was from seeds or 

former understory seedlings. At the time this 

study was begun, the regenerated stand was 11 

years old and, predominantly green ash (82 

percent of the stems and 59 percent of the dry 

weight). Other jmportant tree species were: 

American elm, blac.: willow LSa1i.x nigra), eastern 

cottonwood (Populus deltoides), and red maple. 

Oaks, sweetgum, and sugarberry were rarely 

encountered. Dry-weight yields were 41.6 t/ha 

for suniner and 35.8 t/ha for winter (Francis 

1984). The soil in this fiat and poorly drained 

area was in the Alligator series --- very fine, 

montnorillonitic, acid, thermic Vertic 

I/ Paper presented at the Third Biennial Haplayc~,ts, Four 0.13 ha blocks were cut in the 

Southern Silvicultural Research Conference, winter or 1981-82. The blocks were located on 

Atlanta, Georgia, ;:ov. 4-6, 1986, the site 5y dividing the area available for 

21 Research Forester, Institute of Tropical samplin:: (about 4 ha) into four equal sections 

~orestr~, Rio Tiedras, P.?. , Southern Forest and randonly positioning a block within each 

Experinent Station, USDA Forest Service. section. PL41 vezetation in the blocks was 
severed near the groundli-ne and removed from the 

area. Four 0.004-ha plots per block, with buffer zones around each, were laid out for future 

sampling. The assignment of treatments within 

each block was random. Each plot was split into 

two 0.002-ha subplots for summer and winter 

sampling. In each of the 4 years of the study, one plot from each block was sampled. Summer 

sampling took place during August and winter 

sampling in December or January. In years 1 and 

2, all vegetation within the subplot was cut, and 

herbaceous and woody vegetation were weighed 

separately. Herbaceous vegetation was not 

sampled during the winter. Then the entire 

harvest was ovendried and weighed again. A 

subsample for nutrient analysis was extracted 

from each sample. In years 3 and 4, individual 

stems of tree and brushy species were measured 

for height and weight. A sample of each species 

was dried to enable a projection of total dry 

weight from green weight. The separate weighing 

of trees, shrubs, and vines enabled reporting of mass for those stand components in years 3 and 4, 

The semimicro kjeldahl procedure was used to 

obtain values for nitrogen, and the molybdenum 

blue method was used for phosphorous. Potassium, 

calcium, and magnesium were measured by atomic 

absorption spectrophotometry after being taken up 

in dilute acid from ashed tissue. Mean and 

standard deviation were used to analyze the data. 

Results and Discussion 

New growth began to appear in March after 

removal of the sampling stand. By the August 

sampling, sprouts and herbaceous weeds were chest-high, thick, and often matted. The most 

abundant herbaceous weed the first year was Pennsylvania smartweed (Ploygonum pennsylvanicum). Cottonwood, which produced weak and 

spindly sprouts, was dragged down and smothered 

in the dense mat of weeds. Many green ash and 

American elm grew ahead of the early flush of 

weeds; most others apparently survived 

the first-year matting. The weeds were much 

thinner in the slight rises of ground, which were 

probably drier. During the second year, 

smartweed decreased markedly while goldenrod 

(Solidago sp.) increased. In the third year, 

goldenrod was the dominant herbaceous species. 

By the fourth year, shade from the trees had 

increased enough to eliminate most herbaceous 

growth, The herbaceous growth that did occur was mostly confined to gaps between the tree sprout 

clumps. Weights per hectare of herbaceous 

species in the August sampling approximate the 

annual yield (table 1). The greatest yield 

occurred during the first year. Somewhat lower 

in years 2 and 3, herbaceous yields decreased to 

almost nothing in year 4. 

Standing woody biomass increased steadily 

through the 4 years. The difference between summer and winter weights (approximately the 

weight of leaves) increased over the years but 

showed no clear trend in terms of percentage of 

total biomass. The largest annual increase in 

standing woody biomass occurred in year 1 and 

decreased each year through year 4. The 4-year 

average annual increase of woody biomass 

(calculated from dry woody biomass, summer of 

year 4) was 3-68 t/ha. This yield is comparable 

to the 3.25 t/ha/yr obtained from the original 

stand (Francis 1984), 2.47 t/ha/yr measured by 

Hitchcock (1979) from upland oak-hickory 

regeneration 4 years after a clearcut harvest, 

and 1.84 to 3.48 t/ha/yr for speckled alder 

(Alnus rugosa) in the Lake States (Mattson and 

Flinsauer 1985). Krinard and Johnson (1981) 

harvested the equivalent of 3.63 t/ha/yr from an 

11-year-old seeded oak stand containing a mixture 

of volunteer species, and 4 years later recorded 

7.85 t/ha/yr of biomass from the coppice regrowth 

(Krinard and Johnson 1986). This higher yield was most likely a result of higher individualtree vigor gained through lower density and less 

competition. 

Table I.-- Biomass harvestea from sample plots in each of 4 years 

Year 

Type of sample 1 2 3 4 

---------- Metric tons/hectare ---------- 

Summer green herbaceous 11.5 2 4,4* 5.2 2 2.3 5.5 + 2.9 1.0 + 0.8 

Summer dry herbaceous 3.5 2 1.0 1.8 + 0.8 2.2 + 1.3 0.3 + 0.2 

Summer green woody 12.5 + 3.9 20.1 2 6.1 22.0 + 9.3 28.2 + 5.2 

Summer dry woody 5.0 2 1.6 9.3 + 2.8 12.2 2 5.4 14.7 2 2.8 

Winter green woody 5.9 2 4.3 13.2 2 4.1 17.5 2 3.6 18.3 2 9.0 

Minter dry woody 3.5 + 2.5 8.1 + 2.8 8.0 2 1.9 10.8 2 5.4 

* mean 2 standard deviation; n = 4 in each case 
The number of stems per hectare in years 3 and 

4 averaged 30,663 and 29,077 respectively and 

included both trees and shrubs, The proportion 

of species in the regrowth changed considerably 

from the former stand. Green ash in years 3 and 

4 averaged only 29 percent of the stems; however, 

it was present on ail plots sampled, Generally, 

just the largest and most vigorous ash stems from 

the previous sampling stand coppiced. Those 

coppicing, however, produced an average of 3.9 

sprouts per stump. The second most abundant tree 

in terms of total number of stems in the regrowth 

was cedar elm (Ulmus ~ssifold. Although 

unimportant in the previous stand, it sprouted 

vigorously and produced a large number of stems 

per sprout clump. American elm was also an 

important tree component of the regrowth. It 

produced sprouts that were slightly taller and 

more robust than those of cedar elm. Other 

species represented in the regrowth were water 

hickory (Carya aquatica), sugarberry, water oak, 

willow oak, and Kuttall oak, Black willow and 

cottonwood had disappeared completely. 

Sugarberry was very short and weak compared to 

the other species. The oaks, unimportant in 

terms of percentage of total stems in the 

original stand, increased their prominence by 

nearly universal survival and production of a 

large number of stems per stool. At least one 

oak was present on 38 percent of the 0.002 ha 

plots sampled in years 3 and 4. Green ash 

produced the tallest individual on 81 percent of 

the plots. The average tallest trees per plot in 

years 3 and 4 were 4.3 m and 4.8 m respectively. 

The reproduction of trees in sprout clumps could 

result in more multiple-stemed trees whose 

average size would be smaller with poorer form 

than if these trees reproduced from seed or 

seedling sprouts. 

Brushy species accounted for 21 percent of the 

stems measured in years 3 and 4, There were 

mainly possumhaw (ilex decidua) and hawthorn 

(Crataegus opaca), with a few roughleaf dogwood 

(Cornug drumnondii) and elderberry (Sambucus 

canadensisf. -- These will undoubtedly be 

overtopped soon, Woody vines that contributed 

29.2 and 15.0 percent of the summer woody biomass 

in years 3 and 4 were: blackberry, Rubus sp.; 

trumpetcreeper, Camgsis radicans; moonseed, 

Menispermue canadense; supplejack, Berchemia 

scandens; poison-ivy, zoxicodendron radicans; 

Carolina jassamine, Gelsemiurn sempervirens; and 

wild grape, Vitis aestivalis. The reduction in 

vine biomass may have been due to two processes: 

the steady increase in tree and shrub biomass and 

the death of certain vines. Many trumpetcreepers 

surviving from the original stand grew for a 

couple of years and then died. Also, many 

blackberry canes, which normally live 2 years, 

did not renew themselves after the initial flush 

because of increased shade. By year 4, only 

supplejack had seriously invaded the crowns of 

some of the trees. A vine stage in which large 

areas of tree crowns are matted down and held in 

check for 10 years or more does not appear likely 

to develop in at least the next 2 or 3 years, if 

at all. 

Nutrient concentrations (N, P, K, Ca, and Mg) 

in harvested materials in years 1 through 4 are 

listed in table 2, The accumulation of nutrients 

Table 2.-- Average nutrient concentrations in biomass harvested from plots over a 4-year 

period 

Year 

Season Tissue Nufrient 1 2 3 4 

Summer 

Sumrner 

Winter 

Summer 

Sumer 

Winter 

Summer 

Surnmer 

Winter 

Sumer 

Sumer 

Herbaceous 

Woody 

Woody 

Herbaceous 

Woody 

Woody 

Herbaceous 

Woody 

Woody 

Herbaceous 

Moody 
Table 2.--(cont 'd) , 

Year 

Season Tissue Nutrient 1 2 3 4 

Winter Woody Ca 0.56 0,09 0.82 5 0.15 0.45 5 0.10 0.57 _t 0.05 

Summer Herbaceous Mg 0.25 + 0.06 0,26 2 0-07 0.17 fi 0,03 0.20 5 0.10 

Summer Woody Mg 0.12 + 0.02 0.13 ++ 0.04 0.07 + 0.02 8.10 ++ 0.05 

Winter Woody Mg 0.08 5 0.02 0.20 ++ 0.07 0.05 9 0.00 0.09 + 0.03 

* mean 2 standard deviation; n = 4 in each case 

(kilograms per hectare) in harvested summer biomass are listed in table 3. Due to the 

simultaneous decrease of herbs and the increase 

of woody species, there were relatively minor 

changes in total nutrient content of the summer biomass over the 4 years of regrowth. Although 

substantial quantities of nutrients are withdraw 

by harvesting regrowth on very short rotations, 

this particular soil (Alligator) has huge 

reserves of nutrients (Francis 1984) and could 

supply nutrients to succeeding stands through 

several rotations. 

The regrowth resulting from the harvest of an 11-year-old bottomland hardwood stand dominated 

by green ash produced total biomass at a rate 

similar to the parent stand. A species shift 

away from ash and toward elm and oak has occurred as a result of cutting, If left undisturbed, the 

'n future stand developing from this setting would 

have sizable components of ash, elm, and oak. 

Table 3.-- Nutrient accumulated in biomass harvested over a 4-year period 

year 

Nutrient Tissue 1 2 3 4 

------------------- kiloprams per hectare ------------------ 

Herbaceous 37.5 25.8 24.0 2.6 

Woody 41.2 62.7 75.8 96.0 

Total (78.7) (88.5) (99.8) (98.6) 

Herbaceous 6-2 3.6 3.1 0-6 

Woody 6.9 10.7 9.5 13.9 

Total (13.1) (14.3) (12.6) (14.5) 

Herbaceous 57,3 21.5 22.0 6.9 

Moody 33.7 80.0 40.4 62.1 

Total (91.0) (101.5) (62.4) (69.0) 

Herbaceous 29.4 18,9 21.5 3.1 

Woody 33.4 53.4 67.2 l11,l 

Total (62.8) (72.3) (88.7) (114.2) 
Table 3.--(cont f d) . 

year 

Sutrient Tissue 1 2 3 4 

------------------- kilograms per hectare ------------------ 

iLfg Herbaceous 8.8 4.9 3.7 0.6 

Woody 6.2 11.9 8.6 14.1 

Total (15.0) (16.8) (12.3) (14.7) 

LITERATURE CITED 

Francis, John K. Yield and nutrient removal by 

whole-tree harvest of a young bottomland 

hardwood stand, Res. Note SO-305. New 

Orleans, LA: U.S, Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1984. 4 p. 

Nitchcock, H, C., 111, Biomass of southern 

hardwood regeneration estimated by vertical 

line sampling, Journal Forestry. 77:474-477; 

1979. 

Krinard, R. M., and Johnson, R. L. Description 

and yields of an 11-year-old hardwood stand on 

Sharkey clay soil. Res. Note SO-265. New 

Orleans, LA: U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1981. 2 p. 

Mattson, J. A,, and Winsauer, S. A. The 

potential for harvesting "Puckerbrush" for 

fuel. Res. Pap. NC-262. St. Paul, PIN: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1986. 6 p. 

McAlpine, R. G., Brown, C. L., Harrick, A. Me, 

Ruark, H. W, "Silage" sycamore. Forest 

Farmer. 26: 6-7. 1966, 

McGee, Charles E. The effect of fire on species 

dominance in young upland hardwood stands. In: 

Proc, Mid-South Upland Hardwood Symposium for 

the Practicing Forester and Land Manager; 1980, 

April 30; Harrison, AR. S & PF Tech. Pub. 

SA-TP-12. Atlanta, GA: U, S. Department of 

Agriculture, Forest Service, Southeastern Area. 

1980. 

Krinard, R. M., and Johnson, R. L. Hardwood 

regrowth and yields on bottomland clay soil 

following clearcutting, Res. Note SO-323. New 

Orleans, LA: U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1986, 4 p. 
REGENEMTION OF BOTTOMLAND 

1 f BY PRE-WVEST PMTING - 

2f 3. L. Chmbers, B. C. Stuhlinger, and R. G. P. Clifton - 

Abstract.--Twenty one-hectare circular treatment plots wereestablished in an over-mature cottonwood-willow stand in 

south-central Louisiana. Seedlings of baldcypress, green ash, 

sweet pecan, water oak, and Nuttall oak were planted within a 

0.25 ha circular nested plot on each treatment plot. All 

seedlings were then allowed to establish themselves for a period 

of one year before harvesting treatments were applied. Five 

harvest level treatments replicated four times were applied in a 

randomized design. Harvest treatments consisted of removal of 

30, 45, 60, 75, or 100 percent of the plot basal area. A 

conventional harvest of sawtimber trees took place during the 

second spring and summer after planting. Additional 

non-commercial trees were then felled to reach specified harvest 

levels for each respective treatment. Survival and growth were 

evaluated for harvesting effects, at the end of the growing 

season. First-year survival ranged from 88 to 99 percent and 

height growth was greatest for green ash and Nuttall oak. At 

the end of the growing season following harvest (second growing 

season in the field), survival ranged from 50 to 70 percent, 

Mortality from harvesting was estimated to range from 17 to 23 

percent. Height growth was slow but adequate for the species 

studied. Green ash and Nuttall oak showed the most rapid height 

growth with 39 and 30 percent of the seedlings, respectively, 

exceeding a height of 1 m after 2 growing seasons in the field, 

INTRODUCTION 

Regeneration of bottomland hardwoods has been a 

subject of considerable research. Well 

established methods exist for regeneration of 

bottomland hardwood stands which have desirable 

species composition and adequate advanced 

regeneration (~ohnson 1985). However, many 

high-graded stands exist which have undesirable 

overstory composition , midstories of tolerant 

slow growing species and understories with 

inadequate or undesirable advanced regeneration 

(carve11 and Tryon 1961, Janzen and Wodges 

1985). In other cases the forest manager may 

simply want to increase the numbers of certain 

preferred species in the new stand. The most 

prevalent means of reproducing stands with these 

I/ Paper presented at the Southern Silvicultural Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

21 Associate Professor, Research Associate 

and Graduate Research Assistant, respectively , School of Forestry, Wildlife, and Fisheries, 

Louisiana Agricultural Experiment Station, 

Louisiana State University Agricultural Center, 

Baton Rouge, LA, U.S.A. 70803. 

undesirable attributes is to clearcut and plant. 

However this type of operation is capital 

intensive, often requiring intensive site 

preparation, and several years of continued 

cultural practices. In addition, clearcutting 

may be an unacceptable regeneration practice on 

some areas or for some ownership objectives. 

Underplanting or pre-harvest planting is one 

method that may have potential for rectifying 

the inadequate advanced regeneration problem 

(Tworkoski et al. 1983, Nix et al. 19851, 

Pre-harvest planting may also provide an 

alternative to the often used clearcut and plant 

regeneration method. 

The objectives of this paper are to: describe 

the initial success of underplanted seedlings; 

evaluate the impacts of animal damage on 

pre-harvest planted seedlings, and describe the 

effects of logging activities on survival of the 

pre-harvest planted seedlings. Future work will 

evaluate the effects of various levels of 

overstory removal and understory control on the 

ultimate success of this regeneration method. 
METHODS AND PROCEDURES 

Study Area 

The study area is located in the Atchafalya 

river basin in south-central Louisiana, This 

site, @rovided by Williams Inc,, is a 32.4 ha 

bottomland hardwood site with an overstory 

primarily of over-mature cottonwood (Populus 

deltoides), and black willow (Salix 

mid-story is composed primarily of boxelder 

(H neRundo), and red maple (Acer rubrum). 

Several sloughs cross the area and baldcypress 

(Taxodium distichum) is the predominant species 

in these areas. Understory vegetation on the 

area is mainly composed of herbaceous plants and 

poison ivy vines. The site is subject to 

irregular flooding in the late spring and early 

summer. Some low lying portions of the stand 

are flooded annually in the winter and early 

spring with standing water remaining on those 

areas until the beginning of the growing season. 

Plot Selection and Establishment 

An initial ground cruise of the area was used to 

determine the useable portion of the area for 

this study. Twenty 1.0 ha circular treatment 

plots were established on relatively homogeneous 

areas within the stand. At the time of 

establishment the interior 0.25 ha circular 

central portion of each plot was designated as 

the measurement plot. The larger trestment plot 

area served as a buffer from adjacent plots, 

Once plot locations and boundaries were 

established, basal area, density and species 

composition was determined for each plot for all 

trees equal to or greater than 10 cm in dbh. 

During the winter of 1983-84 thirty 1-0 

bare-root seedlings (from the Louisiana Office 

of Forestry Nursury) of baldcypress, green ash 

(Fraxinus pennsylvanica), Nuttall oak (Quercus 

nuttallii), water oak (Q. nigra) and sweet pecan 

(Carya illinoensis) were planted on each 

measurement plot following a modified Nelder 

plot design. The planting design consisted of 

15 equally spaced planting spokes radiating from 

the center of each plot. Ten seedlings of a 

single species were planted at a 3.0 m spacing 

along a spoke and each species was replicated on 

3 such spokes of each plot. 

Harvesting Design 

After one growing season in the field, the 

treatment plots were scheduled for partial 

overstory removal. Five overstory removal 

treatments consisting of a 30, 45, 60, 75 and 

100 percent basal area removal were randomly 

assigned to the plots. All treatments were 

replicated four times. Trees marked for 

commercial harvest were primarily sawtimber size 

trees of cottonwood, black willow, baldcypress 

and sycamore. Mature and overmature cottonwood 

and willow represented 87 percent of the 

commercial harvest. Cull trees and trees of 

non-commercial value were then felled until the 

desired level of overstory removal was attained. 

Trees to be felled were marked so that the 

remaining basal area was relatively evenly 

distributed across each plot. Boxelder and red 

maple made up the majority of the non-cnrmercial 

species cut. Logging took place from April 

through September of 1985 and consisted of 

chainsaw felling and tree length skidding of 

trees to landings. Landings and skid trails were 

not designated and no special precautions were 

taken to avoid measurement plots during the 

logging operation. Although skid trails were 

not designated, primary skid trails developed 

naturally and became the areas of most frequent 

travel. 

Measurements 

Height, root collar diameter and damage by cause 

were recorded for all underplanted seedlings 

initially and at the end of each growing season. 

Cause of damage was segregated into several 

categories including, mortality by natural 

causes (low seedling vigor, poor planting or 

micro-site conditions, and animal damage) and 

logging related damage (skidder damage, felled 

tree or slash, located on a deck or landing). 

If a seedling was present before logging and 

missing after logging, evidence of the cause was 

ascertained by visual appearance at the 

seedlings previous location. This method of 

damage assessment may have caused some errors in 

assignment of cause of damage and may have led 

to an overestimation of logging related damage. 

Since final growth measurements for this paper 

were taken only a few months after harvest 

activities were concluded, differences among 

overstory treatments were not analyzed. It is 

unlikely that sufficient time had elapsed for 

treatment effects on growth to have taken place. 

Results are thus a composi-te analysis of the 

data. 

RESULTS AND DISCUSSION 

Survival and Causes of Mortality 

Survival during the first growing season after 

outplanting was relatively high for all species 

(94.1 percent). First year survival ranged from 

a low of 87.8 percent for sweet pecan to a high 

of 98.7 percent for baldcypress (Table 1). 

After harvest (end of the second growing season) 

survival had declined considerably, but was 

still adequate for bottomland hardwoods. 

Survival after two growing seasons in the field 

averaged 64 percent and ranged from a low of 

50.3 percent for baldcypress to a high of 74.2 

percent for green ash (Table 1). 

Mortality during the first growing season in the 

field was largely caused by animal damage, 

however, some seedlings did succumb because of 

low seedling vigor, poor planting technique and 

micro-site conditions. During the second 

growing season, continued animal damage and 

harvest related activities led to additional 

mortality. Mortality from animal damage and 

other natural causes led to a two year total 
Table 1. First- and second-year survival of 

five pre-harvest planted bottomland hardwood 

species. 

First-Year Second-Year 

Species Survival Survival 

- n percent n percent 

Sweet Pecan 527 87.8 317 52.8 

Green .Ash 589 98.2 445 74.2 

Baldcypress 592 98.7 302 50.3 

Water Oak 548 91.3 414 69.0 

Nuttall Oak 567 94.5 431 71.8 

mortality averaging 16.8 percent. The highest 

mortality from these natural causes was 

associated with baldcypress and sweet pecan 

(26.5 and 23.8 percent respectively). Green ash 

was the least affected species with only 9.2 

percent of the seedlings being destroyed by 

natural causes (Table 2). Logging related 

mortality was somewhat more evenly distributed 

across the planted species. Logging caused 

mortality averaged 19.6 percent and ranged from 

a low 16.7 percent for green ash to a high of 

23.3 percent for sweet pecan (Table 2). 

Table 2. Mortality by cause for five 

pre-harvest planted bottomland hardwood species. 

Natural Logging Related 

Species Mortality Mortality 

- n percent percent 

Sweet Pecan 143 23.8 140 23.3 

Green Ash 55 9.2 100 16.7 

Baldcypress 159 26.5 139 23.2 

Water Oak 8 0 13.3 106 17.7 

Nuttall Oak 6 6 11.0 103 17.2 

Height Growth 

Height growth of all species was relatively 

slow. Green ash and Nuttall oak grew the most 

rapidly, averaging 30.7 and 25.5 cm 

respectively. However, slow initial height 

growth is comon among most moderately tolerant 

tree species and is not generally expected to 

increase rapidly for the first three to five 

years after planting, Baldcypress the most 

intolerant species planted was so heavily 

damaged by animals (main stems were clipped off 

a few cm above ground-line) that accurate 

estimates of its potential height growth could 

not be determined. Average height for 

baldcypress after two years in the field was 0.8 

cm less than when it was planted. Mean height 

for all species was reduced by animal browsing 

or clipping of the main stem (Table 3). The 

mean height for undamaged seedlings exceeded the 

overall mean seedling height by 20.0 cm. 

One way of predicting future success of 

regeneration is to establish a "target" 

seedling, a seedling of sufficient size to 

Table 3. Seedling height and percent exceeding 

target size two years after outplanting, 

Mean Seedlings 

Overall Weight of Greater 

Mean Undamaged than 

Species Height Seedlings 1.0 rn tall 

- cm - cm percent 

Sweet Pecan 3 9 4 3 1.3 

Green Ash 8 5 101 38.7 

Baldcypress 5 5 8 2 6.6 

Water Oak 6 0 7 9 11.4 

Nuttall Oak 7 8 9 4 30.2 

successfully compete and to attain a dominant or 

codominant position in the stand at maturity. A 

target size should be set based on data taken in 

the early years of stand development and a 

tracking of their success at some specified time 

later in the rotation. However no long-term 

studies exist for pre-harvest planting 

conditions in bottomland hardwood stands. We 

therefore arbitrarily set 1.0 m as a potential 

target size for initial comparisons of success 

for the study species. As shown in table 3 only 

Nuttall oak and green ash had substantial 

numbers of seedlings reaching or exceeding the 

specified target size (30.2 and 38.7 percent 

respectively). Sweet pecan was the poorest 

performer with only 1.3 percent of the surviving 

seedlings reaching the target height after two 

years in the field. 

CONCLUSIONS 

Survival of pre-harvest planted bottomland 

hardwood seedlings after two growing seasons in 

the field averaged an acceptable 64 percent, 

Natural mortality, which was principally related 

to animal damage averaged less than 17 percent. 

Logging caused mortality was less than 20 

percent overall and occurred mainly along 

primary skid trails and at log decks or 

landings. 

Early height growth was slow as is comon for 

planted seedlings of moderately tolerant 

bottomland hardwood species. Height growth can 

probably be expected to increase significantly 

after three to five years in the field if the 

planted seedling can maintain a competitive 

position within the stand. Baldcypress height 

growth was severely limited by rabbit damage and 

deer browse. Successful establishment of 

baldcypress by pre-harvest planting would almost 

certainly require protection from such damage, 

Target heights need to be established to allow 

prediction of regeneration success of various 

bottomland hardwoods from early measurements, 

An arbitrarily chosen height of 1.0 m was used 

for comparison of species in this study. Only 

Nuttall oak and green ash had a large number of 

seedlings reaching the target size, Species 

like sweet pecan, however, may not normally be 

expected to reach this height in high numbers 

even under more intense management regimes. 
Therefore, long-term results tracked from early 

height measurements will be necessary for future 

prediction of regeneration success. Although 

early results seem promising, long- term results 

are necessary before pre-harvest planting can be 

retomended as an appropriate regeneration 

method on an operational basis. 

LITERATURE CITED 

Carvell, K. L. and E. H. Tryon. 1961. The 

effect of environmental factors on the 

abundance of oak regeneration beneath 

mature oak stands. Forest Sci. 7:98-105. 

Janzen, GI C. and J. D. Hodges. 1985. 

Influence of midstory and understory 

vegetation removal on the establishment and 

development of oak regeneration. p. 

273-278 E. Shoulders (~d.). Proc. Third 

Biennial South. Silv. Res. Conf. held 

November 7-8, 1984. Atlanta, GA. USDA-FS 

South. For. Expt. Stat. Gen. Tech. Rep. 

30-54. 588 p. 

Johnson, R. L. 1985. Don't overlook those 

bottomland hardwoods. Forest Farmer 

44(5)33-35. 

Nix, L. E., J. L. Haymond, and W. G. Woodrum, 

111. 1985. Early results of oak 

enrichment plantings in bottomland 

hardwoods of South Carolina. p. 155-158 & 

E. Shoulders (Ed.). Proc. Third Biennial 

Southern Silv. Res. Conf . Atlanta, 

Georgia. Held November 7-8, 1984. USDA-FS 

South. For. Expt. Stat. Gen. Tech. Rep. 

SO-54. 588 p. 

Tworkoski, T. J., D. Wm. Smith, and D. J. 

Parrish. 1983. Response of underplanted 

seedlings to canopy removal in upper 

Piedmont hardwood stands. p. 185-188 & 

Earle P. Jones (~d.). Proc. Second 

Biennial South. Silv. Res. Conf. Held 

November 4-5, 1982, Atlanta, GA. USDA-FS 

Southeastern For. Expt. Stat. Gen. Tech. 

Report SE-24. 514 p. 
Cherrybark Oak Enrichment Plantings Appear Succes ful 

After Seven Years in South Carolina Bottomlands f 

L. E. Nix and S. K. Cox 2 

ABSTRACT.--After seven growing seasons, enrichment plantings of 

cherrybark oak on bottomland tracts in South Carolina appear to be 

doing surprisingly well. Two-year-old bare root seedlings were 

planted in clearcut and shelterwood cut blocks with preharvest disking 

and postharvest herbicide competition control. Seedling survival is 

highly variable, ranging from 20 to 79 percent, with privet hedge 

providing the most severe competition. Seedling size is highly 

variable, ranging from 0.2 to 6.6 inches in ground line diameter and 3 

to 26 feet in total height. Preharvest disking with clearcutting gave 

the best diameter and height growth, 2.3 inches and 16 feet, 

respectively, and by far the best survival, 79 percent. Seedlings 

released during the second growing season with directed herbicide 

application (2% glyphosate) showed no better growth or survival than 

unreleased seedlings. The poorest treatment was the shelterwood 

without disking as competing vegetation continued to flourish after 

overstory removal. Privet, honeysuckle, spice bush and vigorous stump 

sprouts are providing tough competition where present, but many 

seedlings are now free-to-grow saplings and are growing 3-4 feet per 

year as is characteristic of cherrybark oak in a fertile bottomland 

after 6-7 years. 

INTRODUCTION 

The oaks (Quercus s~.) are one of the most 

valuable components of the North American hardwood 

forest, both upland and lowland. In the South 

over half of the hardwoods harvested are from 

bottomland stands (Linde 1980) and oaks are an appreciable portion of the quality material that 

is harvested. Past forest use practices such as 

indiscriminate livestock grazing and highgrading 

have reduced the potential for quality natural 

regeneration in many bottomland hardwood stands. 

Current regeneration practices in bottomland 

stands are not consistently providing a quality 

oak component (Johnson 1979). In the absence of 

advanced oak reproduction or adequate oak 

sprouting, bottomland hardwood stands, formerly 

containing an valuable oak component, are regenerating to fast-growing, light-seeded species 

after clearcutting. Many bottomland sites capable 

of supporting vigorous oak growth no longer have a 

major component of oak in the overstory. 

Artificial regeneration of oaks, such as 

intensively cultivated plantations, is feasible in 

only a few situations where intensive early 

management is economical. Only 12 to 15 percent 

of the Coastal Plain hardwood forest area is 

suitable for such intensive culture (Linde 1980). 

An alternative approach to improving the oak 

component of bottomland stands may be to conduct 

'paper presented at the 4th Biennial Southern 

Silvicultural Research Conference, Atlanta, GA., 

November 4-6, 1986. 

2~ssociate Professor and Research Associate, 

respectively, Department of Forestry, Clemson 

University, Clemson, South Carolina. 

enrichment plantings whereby oak seedlings are established under an overstory or partial 

overstory prior to harvesting the stand. The 

survival to maturity of 15-20 well-spaced oak 

trees per acre may provide an adequate quality 

sawtimber component (Johnson 1980). 

The objective of this study is to evaluate 

the potential of oak enrichment plantings for 

improving species composition in bottomland stands 

where natural oak reproduction is inadequate. 

Additional objectives are to evaluate inexpensive 

competition control methods, such as preharvest 

disking, directed herbicide application and 

partial overstory removal. Early results of this 

study were reported by Nix, et a1 (1985). This 

report presents results of oak enrichment 

plantings after seven years in a South Carolina 

red river bottomland. 

MATERIALS AND METHODS 

Two-year-old, nursery-grown bare-root cherrybark oak seedlings (Quercus falcata var. pagodifolia) were dibble-planted in a red river 

bottomland in Kershaw County, South Carolina. The 

seedlings were planted at 15 x 15 foot spacings in 

one-half of circular fifth acre plots established 

in a first bottom stand of 70-80 year-old elm, 

ash, hackberry, box elder, and sycamore with an 

understory of dense grass and scattered dense 

patches of switch cane and privet hedge as 

described by Nix, et a1 (1985). 

Four treatment conditions, clearcut, shelterwood, and preharvest disking of each, were 

established as 5 acre blocks. Height, basal 

diameter and survival of planted seedlings were determined after 2 and 7 growing seasons. 

Measurements were also made of competing vegeta- 
tion. At the time of the initial measurements 

herbicide (glyphosate-2 percent) was directsprayed on competing vegetation in a 1 meter 

radius around 15 seedlings randomly chosen in each 

treatment block. The herbicide spraying was 

equivalent to about one quart per acre application 

rate. Growth of herbicide-released seedlings was 

compared to that of untreated seedlings paired by 

vigor class in the same block. Experimental 

design of the study is analogous to a completely 

randomized, split-plot design with plots serving 

as replications rather than blocks. The SAS 

General Linear Models Procedure was used for 

analysis (SAS 1985). 

RESULTS Ah3 DISCUSSION 

Survival of planted oak seedlings after 

seven years is highly variable, ranging from 20 

percent in the undisked clearcut treatment to 79 

percent in the disked clearcut treatment 

(Table 1). Seedling survival in the sheltem-ood 

Table 1.--Survival of planted cherrybark oak 

seedlings after two and seven growing seasons in a 

South Carolina red river bottomland. 

Clearcut Shelterwood 

-- Percent -- 49 (63) 38 (59) 

Disk Not Disk Disk Not Disk 

removal of the shelterwood overstory. Eighty-two 

percent of the seedlings lost were found to be 

located in skid trails or debris piles near a 

loading deck. This high loss may not be typical 

of a skelterwood treatment as plot location 

inadvertently occurred near and along old skid 

trails that were reused during the shelterwood 

overstory removal. An increased number of 

seedling plots in the study area might have 

resulted in a reduced proportionate loss of 

seedlings during the residual shelterwood removal. 

Oak seedling mean ground line diameter did 

not differ between clear cut and shelter wood 

treatments, but the disked clearcut treatment 

groundline diameter was significantly greater than 

that of other treatments (Table 2). 

Table 2.--Mean ground line diameter and height of 

planted cherrybark oak seedlings after seven 

growing seasons in a South Carolina bottomland. 

Clearcut Shelterwood 

-- inches -- 

l.g(l5.0) 1.6(11.2) 

Disk Mot Disk Disk Not Disk 

values in parenthesis are seedling total height 

in feet. 

'value in parenthesis is percent survival after 

2 years. 

treatments averages 38 percent with only slight 

improvement due to preharvest disking (+ 15 

percent). A comparison of seedling survival after 

2 and 7 growing seasons indicates that the 

greatest loss (50 percent) occurred in the 

undisked clearcut block between the second and 

seventh years (Table 1). This loss is 

understandable considering the fierce competition 

that ensues after complete overstory removal in 

these fertile bottomland sites. Privet hedge 

(Ligustrum sinense ), spice bush (Lindera benzoin) 

and Japanese honeysuckle (tonicera japonica) as 

well as numerous stump sprouts of overstory 

species, particularly box elder, green ash, and 

sycamore, provided strong, overtopping competition 

for the small cherrybark oak seedlings, which did 

not grow very rapidly for the first several years. 

The appreciable loss in survival of seedlings 

in the disked shelterwood treatment between the 

second and seventh year, a reduction from 79 to 45 

percent survival (Table I), may have been 

primarily due to the logging activity during the 

This difference in ground-line diameter indicates 

a significant reduction in competition due to the 

preharvest disking, but only in the clearcut 

treatment, as disking seems ineffective in 

improving diameter growth in the shelterwood 

treatment. 

Mean total height of planted oak seedlings is 

greatest in the disked clearcut treatment where 

seedlings average nearly 16 feet in height 

(Table 2). As with groundline diameter preharvest 

disking appears to improve helght growth of 

planted oak seedlings in the clearcut treatment 

while the residual shelterwood overstory 

significantly reduces height growth, even when 

preharvest disking is done. Since survival 

interacts with seedling size to determine the real 

success of planting, seedling volume per acre was 

calculated as a stocking factor (Table 3). Mean 

volume of seedlings per acre is more than 3 times 

greater in the clearcut treatment than in the 

shelterwood treatment, but this difference is 

almost entirely due to the effect of preharvest 

disking on survival of planted oak seedlings in the 

clearcut area. 
Disking might have had a similar beneficial 

effect in the shelterwood treatment had not so 

many seedlings been lost to logging damage during 

the residual overstory removal. This supposition 

is supported strongly by the dara of Table 4 which 

show a significant reduction in the height of 

competing woody vegetation in the disked 

shelterwood treatment but not in the disked 

clearcut treatment, 

.Table 3.--Volume per acre of planted cherrybark 

oak seedlings after seven growing seasons in a 

South Carolina bottomland. 

Clearcut Shelterwood 

-- cubic feetjacre -- 2 1 7 

Disk Mot Disk Disk Not Disk 

a~eedling volume = 113 basal area x height. 

Table 4,--Mean height and distance to nearest 

woody competitor of planted cherrybark oak 

seedlings after seven years in a South Carolina 

bottomland. 

Clearcut Shelterwood 

-- feet -- 17.8(2.4) 14.7(3.1) 

Disk Not Disk Disk Not Disk 

%dues in parenthesis are distance to nearest 

woody competitor. 

The mean distance to nearest woody competitor 

(Table 4) also indicates that preharvest disking 

may be effective in reducing competition in both 

the shelterwood and the clearcut overstory 

treatments. Combined with the woody competitor 

mean height data in Table 4, mean distance to 

nearest woody competitor indicates that the disked 

shelterwood treatment is most effective in 

reducing the competition of the planted oak 

seedlings. Unfortunately the loss of seedlings to 

logging damage has likely rendered these results 

inconclusive as the few remaining oak seedlings in 

the shelterwood treatment show a reduction in 

height growth of nearly 4 feet (Table 21, although 

they were under the shelterwood overstory for only 

two years. 

In addition to woody competition near the oak 

seedlings the stocking of naturally regenerated 

woody species was also determine3 on 1/1OO acre 

plots at the center of each fifth acre plot. 

Treatments appear to have bad a significant effect 

on the natural regeneration in the study area 

(Table 5). 

Table 5.--Stocking of naturally regenerated woody 

species after seven growing seasons in a South 

Carolina red river bottomland. 

TREATMENT 

Species Clearcut Clearcut Shelter- Shelter- 

+ Disk wood wood + Disk 

(Overstory Stems Per Acre) 

Ash 7 5 425 50 425 

Bxe 450 775 600 725 

SY c 2 5 125 50 5 0 

Misc 2 5 100 -- 375 

-- - - 

Total 5 7 5 1425 7 00 1575 

- 

(Understory Stems Per Acre) 

Misca 2400 1175 3950 850 

"Miscellaneous understory species are privet and 

spice bush, 

Desirable green ash saplings were increased nearly 

&fold by the disking treatment in both the 

shelterwood and the clearcut areas. Sycamore 

saplings were increased 5-fold by the disking but 

only in the clearcut area. Miscellaneous 

overstory species, which were elm, hackberry, and 

China berry, were also greatly increased by the 

disking treatment. A contributory factor to these 

desirable species stem increases due to disking is 

probably the pronounced reduction in the dense 

grass root mat and in competing understory stems 

(primarily privet and spice bush). The disking 

resulted in a 51 percent reduction in understory 

stems in the clearcut area and a 78 percent 

reduction in ehe shelterwood area (Table 5). 

Although boxelder, an undesirable overstory 

species, was slightly increased by the disking, 

the disking has at least substantially increased 

the desirable species stocking, including that of 

the planted cherrybark oak seedlings. 

Assuming no further mortality there will be 

an average of about 40 cherrybark oak saplings per 

acre in the undisked clearcut area and nearly 160 

per acre In the disked clearcut area (based on the 
simulated planting density of 200 seedlings per 

acre). There will be 60-90 oak saplings per acre 

in the sheltemood areas. The cherrybark oak 

saplings average only 2 to 3 feet less in height 

than the nearest woody competitors and have begun 

to grow rapidly with many saplings now in a 

free-to-grow condition. Based on recent research 

results cherrybark oak becomes a vigorous 

conpetitor if it can just persist for four to five 

years (Krinard and Francis 1983; Johnson 1984). 

The most severe competition in the study plots is 

from privet and spice bush which is approaching 

its maximum height. The cherrybark oak saplings 

are now in their period of maximum height growth 

and should rapidly grow out of the understory 

comperition, especially those in the disked 

treatment areas, 

Many sprouts on larger boxelder and green ash 

stumps (> 20 inches diameter) are dying or appear 

to be losing vigor, thus reducing overtopping 

competition, Many of the planted oak saplings in 

the undisked areas appear spindly and weak, 

especially where privet has completely overtopped 

them. Privet is a severe competitor for the small 

planted oak seedlings and, even after disking, 

vigorously resprouts to quickly overtop planted 

seedlings. The fate of these overtopped seedlings 

is very much in doubt based on their current 

appearance, Post harvest herbicide spraying, as 

done in this study, did not provide effective nor 

long-lasting release for the planted seedlings. 

Although it appeared to improve survival after two 

years, herbicide application actually reduced 

height growth and had no significant effect on 

growth or survival of planted oak seedlings after 

seven years. However, herbicide may have an 

important role in enrichment plantings in other 

areas as a parallel study under different 

conditions showed the effects of herbicide release 

were still detectable after six years (Nix, 

unpublished data). 

CONCLUSIONS 

The results of this study indicate that 

species composition of bottomland stands can be 

enriched by planting quality species, such as 

cherrybark oak, and that preharvest competition 

control, such as disking, can improve survival and 

growth of planted stock significantly. Although 

the sheltemood overstory treatment did not 

improve seedling growth or survival, the 

disproportionate loss of seedlings from logging 

activities may have biased the results of this 

part of the study. The shelterwood treatment 

reduced the growth of both planted seedlings and 

their competition resulting in about the same 

differential in height as in other treatments. 

The sheltemood disked treatment significantly 

reduced the number of competing understory stems 

per acre and increased the number of desirable 

overstory stems equally as well as did the 

clearcut disked treatment. Thus, the sheltemood 

should not be rejected as a potential overstory 

treatment for enrichment plantings. 

Other practical preharvest competition 

control methods should be explored as the disking 

treatment used in this study may not be feasible 

in bottomland stands with different stand 

structure. In addition no attempt was made to do 

an economic analysis of any of the treatments in 

this study. Costs of hand planting, preharvest 

disking, post harvest herbicide application and 

other treatments mentioned will have to be offset 

by the increased value of the oak component in the 

stand at rotation end. 

LITERATURE CITED 

Johnson, R. L. Direct-seeded cherrybark and 

shumard oaks battle natural regeneration 

through 10 years. Southern Journal of 

Applied Forestry. 8(4):226-230; 1984. 

Johnson, R. L. New ideas about regeneration of 

hardwoods. In: Proceedings, Hardwood 

Regeneration Symposium; SE Lumber 

Manufacturers' Assoc.; 1980:17-19. 

Johnson, Re L. Adequate oak regeneration--a 

problem without a solution? In: 

Proceedings, Seventh Annual Hardwood Research 

Council; 1979 May; Cashiers, NC; 1979:59-65. 

Krinard, R.; Francis, J, Twenty-year results of 

planted cherrybark oak on old fields in brown 

loam bluffs. Tree Planters' Notes; Fall, 

1983120-22. 

Linde, I?, Natural and artificial regeneration of 

hardwoods in the lower coastal plain sites. 

In: Proceedings, Hardwood Regeneration 

Symposium; SE Lumber Manufacturers' Assoc.; 

1980:27-31. 

Nix, L. E.; Haymond, J. L.; Woodrum, W. G, 111. 

Early results of oak enrichment plantings in 

bottomland hardwoods of South Carolina. In: 

Proceedings, Third Biennial Southern 

Silvicultural Research Conference; 1984 

November; Atlanta, GA; 1985:154-358. 

SAS (Statistical Analysis Systems). SAS User's 

Guide: Statistics. Version 5 Edition; SAS 

Institute, Inc.; Csry, NC; t985:956 pp, 
STUDIES ON THE BIOLOGY OF CHERRYBAT OAK: 

RECOWNDATIONS FOR REGENEMTION-- I 

2 / John D. Hedges and Gr5g Janzew 

Abstract .--A review of past efforts to regenerate this species 

indicates that the ecological requirements of the species have not been 

adequately cons idered. Advance regeneration (number and size) is 

essential for natural stand regeneration. Results of several recent 

studies of the light requirements for regeneration, growth and 

development in mixed stands, and influence of midstory and understory on 

seedling establishment and development indicate that control of light to 

the forest floor is the key to obtaining adequate advance regeneration. 

Too much light may be as detrimental as too l i t t l e i n that it will favor 

growth of faster growing, more intolerant species. It is suggested that 

several techniques (shelterwood method, mids tory and understory control, 

shelterwood plus control of lower stories, enrichment plantings) may be 

used to regenerate oak stands and that the choice should be based on a 

thorough analysis of the stand conditions. 

INTRODUCTION 

Cherrybark oak (Quercus falcata var . pagodafolia) is one of the most desirable tree 

species in the South. Its good growth rate, 

straight clear stems, and large size make it 

valuable for timber production (Putnam et al. 

1960). In addition, the quantity and quality of 

mast production makes it highly desirable for 

wildlife (Lotti 1965). 

The major silvicultural problem with 

cherrybark oak is during regeneration. There 

are indications that oaks, and particularly 

cherrybark, are not being satisfactorily 

regenerated after the final harvest (Johnson and 

Krinard 1976). The primary reason for oak 

regeneration failures seems to be an 

insufficient number and/or size of advance oak 

seedlings at the time of harvest (Beck 1970, 

Johnson 1975, Sander 1977). Size is of critical 

importance in that small seedlings simply are 

not able to compete successfully with stump and 

root sprouts of some species and very fast 

growing seedlings of other species (Johnson 

1979). A height of 4.5 feet is considered 

minimal for advance growth of northern red oaks 

(Sander 1972) and a similar height seems 

desirable for cherrybark oak. 

liPaper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2'The authors are professor and research 

technician, Department of Forestry, Mississippi 

Agricultural and Forestry Experiment Station, 

Mississippi State University. Contribution No. 

6528 of the Mississippi Agricultural and 

Forestry Experiment Station. 

Some of the problems associated with 

natural regeneration of cherrybark oak may be 

a1 leviated by use of artificial regeneration, 

but there are major problems with this 

alternative. Survival is usually very good, 

but as with natural regeneration, slow early 

growth is a severe problem. Intensive control 

of competing vegetation, usually by 

cultivation, is necessary and expensive. Thus 

the cost of art if icial r e g e n e r a t i o n is 

prohibitive for most landowners. 

This paper reviews some of the past and 

current research efforts and cultural 

practices dealing with cherrybark oak 

regeneration, discusses seedling ecology in 

relation to these practices and current 

research efforts, and suggests recommendations 

for cherrybark oak regeneration. Most of the " 

discussion is specific for cherrybark oak, but 

the results should be applicable to the other 

bottomland red oaks as well as northern red 

oak. 

PAST RaENERATION EFFORTS 

Artificial regeneration efforts have 

largely been directed at improving the early 

growth rate of outplanted seedlings to 

circumvent or alleviate the need for intensive 

competition control. The influence of nursery 

practices and container product ion on the 

early field performance of seedlings have been 

studied at this station. The results from 

several nursery studies (unpublished) indicate 

that seedlings of very acceptable size (2+3 

feet; 318+ inch root collar diameter) and 

vigor can be produced in one growing season 

provided that : (1) nursery density is about 

10 per square foot or less, and (2) the seeds 

are sown early enough in the spring. In 

central Mississippi, it is desirable to seed 
in early March, but no later than the first of 

April . 

Root modification treatments in the nursery 

beds (undercutting and lateral root pruning) 

increase root proliferation, but the results, in 

terms of effect on seedling height growth, are 

inconclus Tve at this t be. 

Studf es of containerized seedlings of 

cherrybark oak and other bottomland red oaks 

(Moorhead 1978, 1981) have shown better initial 

height growth than for bare-root material of the 

same age. However, the difference in growth is 

not great enough to eliminate the need for 

competition control, and the cost per seedling 

is much greater for those grown in containers. 

There may be some advantages of containerzied 

seedlings but the economics of use have not been 

determined. 

Past efforts with natural regeneration have 

dealt mainly with techniques for obtaining 

satisfactory advance oak regeneration. The 

techniques involved modifications of harvesting 

methods and concentrated primarily on use of the 

shelterwood method (Johnson 1979, Sander 1979, 

Lof tis 1983). The shelterwood system has not 

been thoroughly tested with cherrybark oak, but 

the indications are that, as with other red 

oaks, classical shelterwood cuttings will not 

give satisfactory advance oak regeneration. 

Possible reasons why it has not been successful 

will be discussed later. 

SEEDLING ECOLOGY IN RELATION TO 

PAST AND CURRENT REGENERATION EFFORTS 

The above brief review indicates the 

problems we have with cherrybark oak 

regeneration and demonstrates the need for more 

effective mthods of regeneration. More 

importantly, it emphasizes the need for a better 

understanding of the biological requirements of 

the species. In essence we have put the "cart 

before the horse" by researching methods of 

regeneration without a sufficient knowledge of 

the biology of the species. Much of our current 

research effort at Mississippi State is designed 

to learn more about the ecological requirements 

of cherrybark oak. 

Two aspects of seedling biology which are 

very important in regeneration are light 

requirements for mximum grown and juvenile 

growth rates. Two current studies involve 

investigation of light requirements and methods 

for manipulating light for cherrybark oak 

reproduction. In one study, oak seedlings have 

been grown for two years from seed under shade 

houses with light intensities of 100, 53, 27, 

and 8 percent of full sunlight. Results 

demonstrate that cherrybark oak seedlings do not 

require a high light intensity for good growth 

(Table 1). Best development occurred at about 

50% of full sunlight and even at 27% of full 

sunlight height growth was better than under 

open conditions. However, caution must be 

Table ? .--Ef feet of shade on growth of cherrybark oak seedlings at the end of the 

first and second growing seasons. 

--- % Shade Year ? Year 2 Year 2 Growth 

---------- Z ht (cm)--------------- 

-fi~alues in a column that are followed by 

the same letter indicate no statistical difference at the .05 level. 

exercised in extropolating these results to 

field conditions. The shade cloth changed 

only the intensity of light reaching the 

seedlings, but light beneath a stand is 

changed in both intensity and quality (wave 

length). Also, there is likely a difference 

between the field and shade houses in terms of 

the interaction between light and moisture 

availability. It was obvious that soil 

moisture depletion occurred more rapidly in 

the open than beneath the shade houses. 

Observations in numerous older stands 

where oak regeneration was not present 

suggested that the problem was insufficient 

light on the forest floor. Very often 

insufficient light was due to the presence of 

a very dense midstory and understory, usually 

of less desirable species such as American 

hornbeam (Carpinus caroliniana) and eastern 

hophornbeam (Ostrya virginiana). Therefore, a 

study was undertaken to determine how removal 

of this material would influence oak seedling 

establishment and growth (Janzen and Hodges 

1985). The following treatments were 

installed: (1) Inject only. All trees of 

undesirable species greater than 1.0 inch 

d.b.h. and that did not contain at least one 

number three factory grade sawlog were 

injected with glyphssate. (2) Injectlspray. 

Inject as above combined with foliar spraying - - 

with glyphosate of remaining stems (including 

desirable species) and vegetation which could 

be reached with a backpack sprayer (height of 

approximately 10 feet). (3) Control. 

Mids tory and understory left intact. After 

treatment it was obvio;s that much more direct 

sunlight could reach the forest floor and 

after five years there is a significant 

improvement in oak regeneration in terms of 

both numbers and seedling size (Tables 2 and 

3). 

Even though oak advance regeneration is 

present it may be very slow to develop in 
Table 2. --Effect of mids tory and understory control treatments on number of oak seedlings present five years after treatment. 

Trea tmnt - Red White Total 

Inject 1 / 204 7a- 1263a 3310 

Control 653 b 348a 100 1 

Ifvalues in a column followed by the same 

letter indicate no significant difference at the 

.05 level. 

mixed hardwood stands even after a complete 

removal cut (Beck 1970, Johnson 1975, Sander 

1977), and this may be as much of an overall 

problem as lack of advance regeneration (Johnson 

1979). A recent study examined cherrybark oak 

development in even-aged mixed stands comprised 

primarily of oak and sweetgum (Clatterbuck et 

al. 1985). Individual stem development of the 

two species was observed in 160 plots which 

varied in age from reproduction to about 80 

years. The plots were located primarily on old 

field sites. In 35 of the 160 plots oak and 

sweetgum trees were felled and subjected to a 

detailed stem analysis of radial and vertical 

growth patterns. Cherrybark oak exhibited two 

patterns of height development depending on the 

spacing between the oak and cmpeting sweetgum. 

The "restricted" pattern (Figure 1) of 

development occurs when the average spacing 

between trees is about 18 feet or less at the 

pole stage. The cherrybark oak initially grows 

slower than the sweetgum, but if it can get some 

direct sunlight it will eventually outgrow and 

stratify above the sweetgum at age 20 to 25. A 

similar pattern of development has been noted 

for cherrybark oak after a complete clearcut 

Table 3 .--Effect of mids tory and understory control treatments on size of oak regeneration 5 years after treatment. 

Oak Stms/Acre > 20 cm ht 

Trea tment - Red mite Total 

-- -- 

Tnj ect 1 i 4 7 9a- 479a 958 

InjectfSpray 653a 305a 958 

Control 44 b 8 7a 131 

i/~alues in a column followed by the same 

letter indicate no statistical difference at the 

.05 level. 

(Johnson and Krinard 19831, The 

""unrestricted" pattern (Figure 2) occurs when 

cherrybark oak is either a few years older 

than the sweetgum or is essentially open 

grown, Diameter growth rates are much better 

for oak trees with the unrestricted pattern of 

development, but the restricted pattern 

produces trees with more clear wood and a much 

greater mrchantable height, 

Figure 3 is an attempt to portray the 

relationship between cherrybark oak and 

various competitor spgcies in terms of light 

requirements and juvenile growth rates. The 

concepts presented were derived from the 

results of the above studies as well as years 

of field observation. Placement of the 

species indicates relative relationships. 

Exact values are not known at this time. The 

differences be tween species apparently reflect 

differences in efficiency of light utilization 

at different int ensir ies for net primary 

production, especially as reflected in height 

growth. 

The figure and available data indicate 

that under open conditions (high light 

intensity) cherrybark oak is not a good 

competitor when compared to fast-growing 

species such as ye1 low poplar (Lirodendron 

tulipifera). On the other hand, cherrybark 

oak is a persistor. It is able to survive and 

grow at light intensities which are Ear too 

low for most species which have a fast 

juvenile growth rate at high light 

int ens it ies . At very low light intensities 

cherrybark oak can not compete with the very 

tolerant species such as American hornbeam and 

eastern hophornbeam. 

The above ecological considerations have 

implicaticns in designing or choosing 

silvicultural methods for the regeneration of 

cherrybark oak. The key to success, 

especially for natural regeneration, is in 

regulation of the light to the forest floor. 

For cherrybark and other red oaks, past 

regeneration efforts where adequate advance 

reproduction was not present have emphasized 

use of cutting modifications such as the seed 

tree or shelterwood methods rather than 

clearcutting. Use of the seed tree method is 

completely ineffective for increasing oak 

regeneration (DeBell et al. 1968, Johnson and 

Krinard 1983) and use of classical shelterwood 

methods have been erratic and mostly 

unsuccessful (Sander 1979, Loftis 1983, Martin 

and Bix 1986). Lack of success with the 

shelterwood mthod appears to be due to the 

way it is used, h the way it is most often 

used, trees are removed from the upper canopy 

leaving about 30 square feet of basal area if 

a two-cut shelterwood is used and about 60-70 

square feet after the first cut of a three-cut 

shelterwood. Cuttings that heavy will favor 

the growth of fast-growing intolerant species 

such as yellow poplar rather than red oaks 

(Loftia 1983) especially if Little or no lower 

story species are present. A series of 
CBO 

SG 

AGE <yrs> 

Figure 1. --Curnula t ive heigh t-age curves for dominant 

and codominant cherrybark oak (CBO) and 

sweetgum (SG) in stands with the 

restricted pattern of development. 

cuttings much lighter than normally used for a 

shelterwood might be used in such cases to 

regenerate red oaks (Lof tis 1983). On the other 

hand, if there is a dense midstory and 

understory of tolerant species, as there often 

is in bottomland hardwood stands, then no amount 

of cutting in the overstory will give good oak 

regeneration (Janzen and Hodges 1985). There 

will simply not be enough light on the forest 

floor and the cutting will stimulate growth of 

the tolerant mids tory. 

Past efforts at artificial regeneration 

have largely ignored natural seedling ecology. 

On recently harvested sites, even with site 

preparation, the nursery-grown seedlings are 

forced into a competitive position for which 

they are not adapted. Under these open 

conditions , brush, sprout material , and 

seedlings of fast-growing intolerant species 

will simply outgrow the oaks. Thus, it has been 

necessary to use intensive and rather expensive 

cultural practices such as cultivation to 

control the faster-growing competition. 

REGENERATION STRATEGIES 

Cherrybark oak can be regenerated 

artificially by planting or direct seeding and 

under some circumstances this may be the best 

option. This is especially true on sites 

which can be direct seeded (Johnson and 

Krinard 1985). However, on most sites and for 

most landowners the cost of artificial 

regeneration is prohibitive. As with other 

bottomland hardwoods, natural regeneration 

techniques will be of primary importance for 

the foreseeable future (Kellison 1985). 

When natural regeneration methods are to 

be used, the first step should be a detailed 

evaluation of site and stand conditions to 

determine the potential for successful 

regeneration. Evaluation methods such as 

those proposed by Sander et al. (1976), 

Johnson (1980), and Marquis and Bjorkhom 

(1982) can be used. They are based on the 

number and size of advance regeneration stems 

as well as stump sprout potential and can be 

used to evaluate regeneration potential for a 

single species or for all species. If the 

regeneration potential is adequate the stand 

can be regenerated by a complete removal of 

all stems above one inch in diameter. When 

the regeneration potential is not adequate the 

task becomes one of securing enough advance 

regeneration before the final harvest. There 

are a number of options which will work, but 

they are site and stand specific so it is 

extremely important to match the 

recommendation to the stand. The following is 
AGE (yrs> 

Figure 2.--Cumulative height-age curves for representative trees of both cherrybark oak 

(CBO) and sweetgum (SG) in stands with 

the unrestricted pattern of development. 

a list and brief description of some options 

which can be used: 

Enrichment planting -- This option has been 

discussed by two other speakers at this 

conference (Chambers et al. 1986, Nix and Cox 

1986) and involves supplementing natural 

regeneration by unde rplant ing of seedlings 

several years before the final harvest. Some 

control of competition in the lower stories may 

be necessary. Direct seeding may be an even 

more attract ive way to supplement natural 

regeneration. Direct seeding has been very 

successful in larger open areas (Johnson and 

Krinard 1985). Sowing beneath a canopy has 

eorked on a few occasions, but in most cases the 

seeds are lost to rodents. Timing of the 

seeding may be important in preventing rodent 

depredation, but success will ultimately depend 

on the development of an effective rodent 

repellent. 

Use of shelterwood method -- Classical 

shelterwood cuttings usually have not been 

successful in regenerating oaks, but as 

suggested by Loftis (1983) very light cuts over 

a period of years may work. Use of the method 

should be confined to stands without a dense 

midstory or understory. This technique has not 

been rigorously tested for cherrybark oak, but 

observations in stands which have received 

light partial cuts indicate that it may work. 

Midstory and understory control -- The 

upper canopy of bottomland hardwood stands in 

the South is often quite open because of past 

cutting. However, light to the forest floor 

may be very low because of a dense midstory 

and understory of tolerant species and 

regeneration of oaks does not occur. Removal 

of these lower stories will greatly increase 

light to the fores t floor and may be all that 

is necessary to obtain advance regeneration of 

oaks and other desirable species. 

Shelterwood plus control of lower 

stories -- In some stands. cut tine will need " 

to be done in both the main canopy and lower 

canopies in order to get sufficient light for 

regeneration. This can be accomplished by a 

shelterwood cut combined with lower canopy 

control by injection or cutting. Care must be 

exercised not to open the stand too much 

(Loftis 1983). 

The above discussion emphasizes the need 

for stand-specific methods for oak 

regeneration and describes some of the 

techniques which may be used. However, it 

must be emphasized that, at least for 
- LighrRequirementforMaximurnGrowth , 

I W S B ELM C BO SG SYC YP 

- increasing juvenile growth rates > 

Figure 3.--Light requirements and juvenile 

growth of cherrybark oak in f~parison with competitor species.- 

= ironwood; SB = sugarberry; ELM = 

elm; CBO = cherrybark oak; SG = sweetgum; SYC = 

sycamore; YP = yellow poplar. 

cherrybark oak, the recmmendations are 

presently tentative. More definitive 

recommndations must await the result of 

long-te nn studies now underway. 

LITERATURE CITED 

Beck, D. E. 

1970. Effect of competition on survival and 

height growth of red oak seedlings. USDA 

For. %em, Res. Pap. SE-56. 7 p. 

Chambers, J. L., H. C. Stuhlinger, and R. G. P. 

Clifton. 

1986. Regeneration of bottomland hardwood 

sites by preharvest planting. Proc. of 

Fourth Biennial South. Silv. Res. Conf . Atlanta, GA. Nov. 4-6, 1986 (this volume). 

Clatterbuck, W. K., 3. D. Hodges, and E. C. 

Burkhardt. 

1985. Cherrybark oak development in natural 

mixed oak-sweetgum stands--preliminary 

results. Proc. of Third Biennial South. 

Silv. Res. Conf. Atlanta, GA. Nov. 7-8, 

1984. p. 438-44. 

DeBell, D. S., 0. G. Langdon, and J. Stubbs. 

1968. Reproducing mixed hardwoods by a seedtree cutting in the Carolina Plain. South. 

Lumberman 217(2704) : 121-3. 

Janzen, G. C., and J, D. Bodges. 

1985. Inf luence of midstory and understory 

vegetation removal on the establishment and 

development of oak regeneration. Proc. of 

Third Biennial South, Silv. Res. Conf. 

Atlenta, GA. Nov. 7-8, 1984. p. 273-8. 

Johnson, R, L. 

197 5, Na tural r e g e n e r a t i o n and development of 

Nuttall oak and associated species. USDA 

For, Ser, Res. Pap. SO-104. 12 p. 

Johnson, R. L. 

1980. Kew ideas about regeneration of hardwoods. Proc. of Hardwood Regeneration 

Symp., Jan. 29, 1980. Atlanta, Ga. p. 

17-19. 

Johnson, R. L,, and R. M. Krinard. 

1976. Hardwood regeneration after seed tree 

cutting. USDA For. Ser, Res. Pap. 

SO-123. 7 p. 

Johnson, R. L., and R. M. Krinard. 

1983. Regeneration in small and large sawtimber sweetgum-red oak stands f 01 lowing 

selection and seed tree harvest: 23-year 

results. South. J. Appl. For. 7:176-84. 

Johnson, R. L., and R. M. Krinard. 

1985. Regeneration of oaks by direct seeding. Proc. of Third Symp, of 

Southeastern Hardwoods, April 16-17, 

1985. Dothan, AL. p. 56-65. 

Kellison, R. C. 

1985. Changing philosophies of hardwood 

management-an update. Proc, of Third 

Symp. of Southeastern Hardwoods, April 

16-17, 1985. Dothan, AL. p. 112-9. 

Loftis, D. L. 

1983. Regenerating southern Appalachian 

mixed hardwood stands with the 

shelterwood method. South. J. Appl. For. 

7:212-6. 

1965. Cherrybark oak (Quercus falcata var. 

pagodaefolia Ell.). &: H. A. Fowells, 

Silvics of Forest Trees of the United 

States, p. 569-72. USDA Ag. Handbook No. 

27 1. 

Martin, A. J., and D. M. Hix. 

1986. Upland hardwood regeneration following clearcut and shelterwood harvests. 

University of Wisconsin-Madison, 

Department of Forestry. Forestry 

Research Notes No. 264. 6 p. 

Marquis, D. A., and J. C. Bjorkbom. 

1982. Guidelines for evaluating regenerat ion be£ ore and af ter clearcut ting 

Allegheny hardwoods. USDA For. Ser. Res, 

Note NE-307. 4 p. 

Moorhead, D. J. 

1978. Effects of container size and growth 

media on the early growth and field 

survival of four southern red oak 

species. Miss. State Univ., Forestry 

Dept., M,S. Thesis. 75 p. 

Johnson, R. L, 

1979. Adequate oak regeneration--a problem 

without a solution. In: &bnagement and 

Utilization of Oak, pr59-65. Proc, of 

Seventh Annual Hardwood Symp., Hardwood 

Research Council , Ashevil le , NC . 
Moorhead, D. J. 

1981. Container size and growth media influence early growth and survival of 

southern oaks in Mississippi. Workshop on 

Seedling Physiology and Growth Problems in 

Oak Planting, Columbia, MO, Nov., 1979. 

USDA Gen. Tech, Rept. NC-62. p. 20. 

Nix, ,L. E., and S. K. Cox. 

1986. Cherrybark oak enrichment plantings 

appear successful after 7 years in South 

Carolina bottomlands. Proc. of Fourth 

Biennial South. Silv. Res. Conf . Atlanta, 

GA. Nov. 4-6, 1986 (this volume). 

Putnam, J. A., G, M. Furnival, and J. S. 

McKnigh t . 1960. Management and inventory of southern 

hardwoods. USDA For. Ser. Agric. Handb. 

No. 181. 102 p. 

Sander, I. L. 

1377. Manager's handbook for oaks in the 

North Central States. USDA For. Ser, 

Gen. Tech. Rep. NC-37. 35 p. 

Sander, I. L. 

1979. Regenerating oaks with the shelterwood system. 2: H. A. Holt and B. C. 

Fischer, Regenerating Oaks in Upland 

Hardwood Forests, p, 54-60. Proc. of the 

1979 John S. Wright Forestry Conf. 

Purdue Univ., W. Lafilyette, IN. 

Sander, I. L., P. S. Johnson, and R. I?. Matt. 

1976. A guideline for evaluating the adequacy of oak advance reproduction. USDA 

For. Ser. Gen. Tech. Pap. NC-23. 7 p. 

Sander, I. L. 

1972. Size of oak advance reproduction: 

key to growth following harvest cutting. 

USDA For. Ser. Res. Pap. NC-79. 6 p. 
SYCAMORE COPPICE RESPONSE TO HARVEST SEASON: 7-YEAR TRENDS' 

Kenneth R. ~oeder~ 

Abstract.--Five season-of-harvest treatments (March, 

April, June, August and October) were imposed in 1979 on a 

12-year-old sycamore (Platanus occidentalis L.) plantation on 

the Northern Coastal Plain of North Carolina. Resulting 

coppice response was evaluated annually for 7 years following 

harvest. The late dormant season harvest treatment (March) 

resulted in significantly taller and larger diameter sprouts 

than those cut at other times of the year, The rate of 

biomass accumulation was also significantly greater for the 

late dormant season harvest treatment coppice. 

Season-of-harvest did not significantly influence the 

number of coppice sprouts per stump after the second growing 

season following harvest. Orginal tree DBH, used as a stump 

diameter index, had a significant influence on the amount of 

sprout biomass produced. Weed competition control appears to 

be just as important in successful coppice stand establishment as it is with hardwood seedling plantations. 

Keywords: Sprout mortality, Biomass, Competition. 

INTRODUCTION 

Asexual regeneration of hardwoods through the 

sprouting of stumps and roots (coppice) is a significant source of new growth in some naturally regenerated hardwood stands (Petruncio 1985). Coppice regeneration has been an integral component of 

forest management in some parts of the world for 

centuries (Rackham 19801, but has been seldomly 

utilized consciously for regenerating natural hardwood stands in the United States. The limited 

research efforts with coppice have shown that quality and yields of regenerated stands can be altered 

by knowledgeable use of coppicing (Buell 1940; Roth 

and Hepting 1943; Downs 1947; Sander 1971; Johnson 

1975; Kennedy 1975; Stroempl 19831, through the 

silvicultural manipulation of those factors influencing coppice response (Lust and Mohammady 1973; 

Blake and Raitanen 1981). The factors include: 

species, fertility, spacing, season-of-harvest, 

weed competition, cultivation, physiology and 

internal chemical controls, rotation length, stump 

diameter, stump height, and stump mortality (Blake 

and Raitanen 1981). 

'paper presented at the Fourth Biennial 

Silvicultural Research Conference, Atlanta, GA 

Paper No. 10747 of the Journal Series of the North 

Carolina Agricultural Research Service, Raleigh, NC 

27695-7601, 

2~raduate Research Assistant, Cooperative 

Hardwood Research t'rogram, Department of Forestry, 

North Carolina State University, Raleigh, NC 

Significant influences have been reported for 

some season-of-harvest coppice studies (i,e.: 

Buell 1940; Wenger 1953; Grano 1955; Longhyrst 

1956). Research has shown that dormant season 

harvests result in more productive coppice growth 

than growing season harvests (Stoeckler 1947; 

Wenger 1953; Roeder and Bansen 1985). However, 

most season-of-harvest coppice studies report coppice response success at a single point in time and 

by the number of sprouts surviving at 1 to 4 years 

following the harvest cut (Blake and Raitanen 

1981). Results reported by Roeder and Bansen 

(1985) on sycamore (Platanus occidentalis L.) indicate that a simple assessment of only the number of 

sprouts at a point in time may be inadequate for 

evaluating success of season-of-harvest coppice 

studies. 

Recent market changes for hardwood biomass may 

make short rotation biomass plantations a viable 

economic alternative to meet fiber and fuel stock 

demands. However, compared to pine plantations, 

hardwoods have relatively high initial establishment costs and require intensive and expensive sixvicultural treatments in order to become successfully established (Malac and Heeren 1979). Multiple cropping through the use of hardwood coppice 

from a single planting may provide the favorable 

economics necessary for just such a biomass production system. 

Continued research into factors affecting 

coppice response and long-term productivity is 

therefore justified. The work reported in this 
paper evaluates sycamore coppice response for a 

continuous period of 7-years following five 

seasonal harvesting treatments, 

MATERIALS AND METHODS 

A 12-year-old sycamore plantation in Hertford 

County, North Carolina on a terrace of the Meherrin 

River WPS chosen as the study site, as an installation of the Coppice Project of the NCSU-Industry 

Cooperative Hard wood Research Program. The plantation, formerly a fertilizer-spacing-thinning study 

of Union Camp Corporation, was blocked to incorporate the fertilizer-spacing-thinning treatments, 

Seven soil series (Myatt, Goldsboro, Eunola, Johns, 

Suffolk, Kenansville and Wagram variant) were identified on the original study site (SCS 19801, but 

could not be fully incorporated in the blocks and 

were therefore considered pert of random site 

variation. 

Since the establishment of this plantation, 

more knowledge has been obtained on site requirements for hardwood species including sycamore end 

sweetgurn (tiquidambir styraciflua L.1 That knowledge would today favor the planting of sweetgum as 

a more productive and better matched species to 

this site. However, the sycamore on this site is 

viable for determining the effect of season-ofharvest coppice treatments, 

Stocking of the sycamore plantation chosen for 

this coppice study ranged from 452 to 988 trees 

(stumps] per hectare, with a mean stocking of 795 

trees per hectare, The five season-of-harvest 

treatments consisted of chainsaw harvesting the 

existing 12-year-old trees within the treatment 

plots at their designated harvest season--March 15, 

April 30, June 30, August 31 and October 31 in 

1979. All trees were cut within 15 cm of ground 

line. The March harvest treatment was installed a; 

a late dormant se2son treatment; the October harvest treatment as an early dormant season treatment; and the April, June and August harvest treatments as progression of growing season harvest 

treatments. The seasonal harvesting treatments, in 

four replications, were assessed during mid-dormant 

season (January) following harvest and in January 

of each of the following 7 years. Plots were 0.072 

hectares in size in one replication and 0.036 hectares in all other replications. 

Diameter at breast height (DBH) was measured 

on all study trees during the dormant season just 

prior to installation of the harvesting treatments. 

These diameters were used as a measure of the 

original tree's dominance in the stand; they also 

served as an indirect measure of the size and vigor 

of each root system, and will henceforth be 

referred to as stump diameter index (SDI). The SDI 

ranged from 4 to 19 cm, These SDI data were then 

used as a covariate adjustment of the coppice 

response variables under study. All analyses and 

values presented are adjusted for SDI. 

The coppice regeneration was measured for 

total height and DBH of the dominant sprout per 

stump, and number and mean height of sprouts by 2,5 

cm DBH class for each stump. Stocking levels were 

assessed as the number of coppice sprouts in each 

diameter class per stump and extrapolated to per 

hectare values, Only living sprouts were assessed, 

Biomass for the coppice and the original sycamore stand was calculated, using equations for 

predicting total green biomass of understory soft 

hardwoods (Phillips 1981). These equations were 

chosen because no satisfactory biomass equations 

specifically developed for sycamore coppice were 

available and the ranges of diameters for the coppice and the original stand closely matched the 

data used to develop the equations, The calcul_sted 

biomass is therefore used as an index for treatment 

comparisons, Biomass was evaluated as mean biomass 

per sprout and per stump, Biomass per hectare was 

used as a measure of total coppice productivity, 

The data were analysed as a randomized 

complete-block design. Treatment responses were 

evaluated for each assessed variable annually usinp 

standard analysis of variance techniques (Steel an: 

Torrie 19801. The productivity trends for each 

seasonal harvest treatment were evaluated by testing for heterogeneity of slopes for height, DBH, 

stocking and biomass productivity over the seven 

assessment years, and incorporated SDI as a covariate adjustment factor (Freund and Littell 1981). 

Significance is indicated at the .05 probability 

level, 

RESULTS AND 3LSCUSSIONS 

Diameter 3ndex 

As a covariate, SDI was found to be significant for total sprout basal area per hectare, biomass per sprout and biomass per heetare, This 

result is supported by the findings of Belanger 

(19799, also with sycamore, and could be expected 

as basal area and biomass are highly correlated. 

No evidence was found to indicate a significant 

contribution of SDI to the number of coppice 

sprouts produced as has been reported elsewhere 

(i,e. : Mattoon 1909; Schrierbeek and Clarke 1984; 

Singh and others 1973), but this may be due to the 

more limited range of SDI found in the sycamore 

plantation. The influence of number of sprouts per 

stump is an important contributor to the total 

biomass produced per stump and is most likely the 

reason that SDI was not found to significantly 

contribute to biomass per stump, 

By the end of the first growing season, some 

sprouts were lost to mortality due to within-stump 

sprout competition for he March, April and June 

harvest treatments (Figure 11, The August and 

October treatments appeared to be free of the 

severe within-st~rnp sprout competition, By the end 

of the 2nd growing season, all treatments were past 

the point of supporting a maximum number of sprouts 

per stump as within-stump sprout competition was 

eliminating the smaller sprouts, Within any given 

year, significenr differences in mean number of 

sprouts per stump due to seasonal harvesting treatments were undetectable after the 2nd growing 
b Harvest Dates 

I Mar 15 

Apr 30 

---. Jun 30 

=*-eAug 31 

****Oct 31 

Dormant Seasons Following Harvest 

Figure 1.--Mean number of sycamore coppice sprouts 

per stump for 7 years following five seasonal 

harvest treatments, 

season. A similar finding was reported by Wendel 

(1975) for Appalachian hardwoods, 

In the period between the 2nd and 4th growing 

seasons, a significant difference in the withinstump mortality rate (slope) was detected (Figure 

1). By the 4th growing season an equilibrium level 

in sprout survival was reached for all seasonal 

harvest treatments. The sprout mortality rates for 

the seasonal harvest treatments from the 4th 

through 7th growing seasons were not significantly 

different, Note that the sprout mortality which 

occurred in this study was due to within-stump 

sprout competition as stump spacings and overall 

growth was such that between-stump sprout crown 

competition was limited, 

The mortality rate of sprouts per hectare 

closely mirrors that of mortality per stump due to 

the general uniformity in stump survival rate among 

the harvest treatments. 

The dominant sprouts from the March harvest 

treatment are significantly taller than coppice 

resulting from the other harvest treatments through 

the 7th growing season (Figure 2). However, the 

rate of height growth is consistant for all treatments indicating that the advantage in dominant 

sprout growth obtained by the March harvest treatment is achieved in the first growing season and 

maintained at least through the 7th growing season. 

The significant superiority of the March harvest treatment is also expressed in mean height of 

all coppice sprouts per stump for any given year 

(Figure 31, In addition, the rate of the mean 

sprout height growth is significantly greater for 

the March treat rnent. This significant diff esence 

in the reported rate of mean sprout height growth 

is the result of actual sprout height growth as 

well as within-stump coppice stand development, 

This coppice stand development occurred earlier in 

the March harvested plots as the result of the 

within-stunp sprout competition eliminating the 

smaller intermediate and suppressed sprouts, thereby increasing the mean height of the surviving 

sprouts, 

The period between the March 15 and the April 

30 harvest treatments appears to have been critical 

to the growth potential of the resultant coppice. 

Cutting trees prior to mobilization of hormones 

and nutrients stored as carbohydrates in the roots 

(March harvest treatment) permits the potential for 

full availability ot these nutrients for subsequent 

coppice response, Cutting after partial mobilization (April harvest treatment) results in a proportional reduction in the coppice response (Wenger 

1953), The Lowest level of nutrient reserves in 

the roots is prior to full leaf expansion (Alban 

1985) which occurred before the June 30 cutting 

treatment in this study. 

Harvest Dates 

mmrc Apr 30 

-=-~Jun 30 

=e-nAug 31 

ee**Q)ct 39 

Dormant Seasons Foilowing Harvest 

(years) 

Figure 2.--Mean height of the dominant sycamore 

coppice sprout per stump for 7 years following 

five seasonal harvest treatments, 
Dormant Seasons Foltowlng Harvest 

(years) 

Figure 3,--Mean height of all sycamore coppice 

sprouts per stump for 7 years following five 

seasonal harvest treatments. 

Dormant Seasons Following Harvest 

(years) 

Figure 4.--Dominant coppice sprout height growth of 

dormant season harvests of Yellow-poplar, red oak, 

white oak (from Wendel 19751, and sycamore. (Note: 

species indentification of oaks only to subgenus 

level. 1 

The rate of dominant sprout growth of late 

dormant season harvested sycamore coppice was initially faster than that reported for dormant season 

harvested oak (Quercus sp.1 and yellow-poplar 

(Liriodendron tulipifera L.1 on excellent and fair 

natural stand sites (about 55-years-old) in West 

Virginia (Wendel 1975) (Figure 41, but appears to 

be decreasing by the 7th growing season. Yellowpoplar surpassed sycamore cumulative height growth 

during the 6th growing seagon, while red oak has 

caught up to sycamore by the end of the 7th growing 

season. 

Diameter at Breast Height 

Mean diameter growth of the dominant stump 

sprout from the March harvest treatment was significantly larger than the dominant sprouts from the 

other harvest treatments through the 7th growing 

season (Figure 5). The rate of diameter growth was 

also significantly superior for the March treatment. This superior diameter growth of the March 

treatment sprouts is a function of their earlier 

start at the beginning of the initial growing season following harvest treatment, earlier stand 

development and dominance expression of the competing sprouts within each stump. Once a sprout 

acquires a superior crown position in the withinstump sprout canopy, the sprout is able to maintain 

or expand its dominance as it suppresses smaller, 

slower growing sprouts, 

I Harvest Dates 

-Mar 15 

.... Apr 30 

--qJun 30 

-8-*Aug 31 

****Oct 31 

C 

I 

C 

I 

Dormant Seasons Following Harvest 

(years) 

Figure 5,-Mean diameter at breast height of the 

dominant sycamore coppice sprout per stump for 

7 years following five seasonal harvest 

treatments. 
Mean sprout diameter growth reflected the same 

trends and relationships as for dominant sprouts 

(Figure 51, Overall, the rates of mean sprout 

diameter growth were less than that for dominant 

sprouts , 

Biomass 

The March harvest treatment consistantly produced significantly larger sprouts than the other 

season-of-harvest treatments, These sprouts, 

because of their larger size and inferred larger 

photosynthetic area, grew at a significantly faster 

rate than sprouts from other harvest treatments, 

Between the 6th and 7th growing seasons, the rate 

of biomass growth increment for the March harvest 

treatment declined (Figure 6). This decline was 

due to widespread vine competition, particularly 

in replication one of the study. 

Honeysuckle (Lonicera japonica Thunb,) competition was so severe in some instances that the 

sprouts were physically damaged, the effects of 

I Harvest Dates 

Dormant Seasons Following Harvest 

(years) 

Figure 6.--Green biomass productivity per stump of 

surviving sycamore coppice sprouts for 7 years 

following five seasonal harvest treatments. 

Harvest Dates 

Mar 15 20 ' 

#em* Apr 30 

**** Jun 30 

Dormant Seasons Following Harvest 

(years) 

Figure 7,--Mean green biomass productivity per 

stump of surviving sycamore coppice sprouts 

for 7 years following five seasonal harvest 

treatments. 

which were significant when dominant sprouts were 

involved. The biomass growth prior to the vine 

induced mortality is lost productivity. The growth 

rate decline detected for the March harvest treatment is also evident in dominant sprout height 

(Figure 21, dominant DBH (Figure 5), sprout biomass 

per stump (Figure 7) and total sprout biomass per 

hectare (Figure 8) due to dominant sprout 

mortality. 

The mortality of dominant coppice sprouts 

through breakage or death, has a severe impact on 

the biomass productivity of a stump system as illustrated by the biomass decline of the March harvest 

treatment during the 7th growing season and the 

June and August harvest treatments at the 4th growing season (Figure 7). The effects of sprout mortality on a particular stump may be buffered on an 

area basis by the increased growing space available 

to the surrounding coppice stand (Figure 8). Loss 

of sprouts may be symptomatic of a stump in poor 

health whose loss will cause a cumulative decline 

in total area biomass productivity. 

The total coppice biomass produced from the 

March harvest treatment, although significantly 

superior to the other season-of-har est treatments, 

amounts to less than 1.2 Mg ha-'yr-' of ovendry 

biomass over 7-years due to the poor quality of 
Harvest Dates 

A 

v -Mar t5 /"". llLl I ..em Apr 30 / 

Oorment Sse8onr Foflowtng Harvest 

(year81 

Figure 8.--Mean green biomass productivity per 

hectare of surviving sycamore coppice sprouts 

for 7 years following five seasonal harvest 

treatments. 

this site for sycamore. T e o iginal seedling 

stand produced 2.52 Mg haefyr-I of ovendry biomass 

over 12-years prior to coppicing. On a good site 

for sycamore located in the county south of this 

study, Torreano (1986) rplporp biomass yields 

ranging from 4.74 M % ha- yr- for 6-year-old seedlings to 2.14 Mg ha yr-l for a combined 6 year 

growth cycle consisting of 4-year-old seedling 

yields and 2-year-old coppice yields, 

CONCLUSIONS 

The superior productivity of sycamore stump 

coppice from late dormant-season-harvested trees 

(March treatment) is evident in sprout height, DBH 

and biomass growth. The uniformity of the rate of 

height growth of dominant coppice sprouts for all 

seasonal harvesting treatments is a partial 

reflection of the site index while sprout height at 

a point in time is more .a function of the actual 

growing months experienced. 

The superior rate of dominant sprout diameter 

growth from the late dormant-season-harvested trees 

has the greatest impact on the rate of total biomass productivity. Coppice from the March harvest 

treatment may utilize the full contigent of stored 

nutrients in the root system, and the full initial 

growing season for sprout growth, to gain a growth 

advantage over later harvest treatment coppice. 

The earlier within-stump sprout competition from 

the March harvest treatment ensures early elimination of some of the subdominant sprouts and allows 

dominant sprouts to take advantage of the increased 

growing space. 

The number of sprouts per stump is affected by 

the season-of-harvest until the carrying capacity 

of the stumps and site is reached. On this site, 

the carrying capacity for sycamore was reached 

after the 2nd growing season, Different species and 

site qualities are expected to shift this equilibrium point. 

Weed competition control may be as important 

in hardwood coppice plantation management as it is 

recognized to be in hardwood seedling plantations, 

This may have a significant effect on the assumptions made to economically justify coppice plantation management systems, thereby dictating directions for technology development, 

The lowest level of resultant hardwood coppice 

productivity occurred to those plants cut during 

the active season when the root systems are at 

their lowest energy level. Therefore, pine plantation site preparation efforts will be most effective in controlling hardwood competition if 

performed during the growing season. 

ACKNOWLEDGEMENTS 

The author wishes to thank Union Camp Corporation for its cooperation and North Carolina State 

University, School of Forest Resources, Cooperative 

Hardwood Research Program for its support. 

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response to seasonal cutting. Journal of 

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1985. 54 pp. Thesis. 

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of understory hardwoods. U.S. Department of 

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Forest Experiment Station, Research Paper 

SE-223; 1981, 22 pp. 

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vegetation and uses in England. London: E, 

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Sciences, University of Florida, Gainesville, 

FL. 1985: 41-46. 76 pp. 

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Thesis. 

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SHORT-ROTATION SEEDLING AND COPPICE 

BIOP.";ASS YIELDS AND NtJTRIEW CONTENT 

OF SEWN TWE SPECIES IN PJORTH ~~~RoLIN&' 

S, J. Torreano and D. J, Frederick 

Abstract,--Plbovqround biomass production and nutrient 

content for seven-year-old seedlings and two-year-old coppice 

grown on a Coastal Plain red river bottomland and Piedmont 

upland are present&, Spacings of 0.8x1.5, 1.5x1.5, and 

2.5xl.5 rn were used, On the bottomland, swetsum 

L.) produced the greatest seven-year 

sdling biomass yields (52.7 Mq ha; 0-8x1.5 m spacincl, 

follow& by wearnore (Platanus bccihentalis L.) , -and Gropean 

black alder (Alnus glutinosa L. Gaertn.). Loblolly pine 

(Pinus taeda L,) produced greater seedling yields than hardwoods on the upland site and all except swetgum on the 

bttomland. Seedling and coppice yields were generally 

greater at narrower spacings on both sites. Higher nutrient 

concentrations in young seedlings and coppice suggest that 

longer rotations will be needed to increase nutrient utilizat ion efficiency, 

Greater use of hardwoods for pulp, composite 

wood products, and energy has created a need to 

grow wood fiber more productively. One 

silvicultural regime king consider& is shortrotation intensive culture (SRIC). SRIC can 

increase hardwod biomass yields over those of 

unmawged, natural stands (Belanger and Saucier 

1975). However, hardwoods have specific site 

requirements and proper matching of species to 

site is necessary for maximum yields (Kellison and 

others 1979). An additional factor in the 

successful application of SRIC is the coppicing 

ability of hardwoods, Little information exists as to whether indigenous species will coppice 

adequately to maintain high productivity levels 

under SRIC regimes. Information on management 

practices which maximize the survival and 

productivity of coppice is needed for planning 

multiple rotations from seedlings, 

SRIG with intensive harvesting places higher 

demands per unit time on site nutrient pools 

compared to conventional management (Hansen and 

Baker 1979). Documentation of nutrient removal 

from harvesting of SRIC stads is neded so that 

comparisons of nutrient utilization efficiency can 

be made among species and sites, 

-11 Paper presented at the Southern 

Silvicultural Research Conference, Atlanta, C14, 

Graduate Research Assistant, and 

Professor, respectively, School of Forest 

Resources, North Carolina State hiniversity, 

Raleigh, K 27695-8002, 

Objectives of thi's study were to compare 

biomass yields and nutrient content of seedlings 

and coppice grown under SRIC on a Coastal Plain 

red river bottomland and Piedmont upland in North 

Carolina. 

MATERIALS AND METHODS 

Sample Stands 

Two plantations were established in May, 

1979. The first is located on a floodplain of the 

Roanoke River in Bertie County, North Carolina. 

The soil on this Atlantic Coastal Plain red river 

bottomland is a Congaree fine, sandy loam 

(Cawthorn 1970). Site preparation man after the 

original bottomland hardwood stand was harvested, 

and consisted of shearing residuals, windrowing 

and burning, followed by double-discing. After 

discing, the site was treated with glyphosate. 

Seedlings (1-0) of seven species: European black 

alder (Alnus glutinosa L. Gaertn) ; sweettgum 

(Liquidambar styraci flua L,) : loblolly pine 

(Pinus taeda ' l,) ; eastern cottonwood (Populus 

deltoides Bartr. ex Marsh) ; sycamore (Platanus 

occidental i s L.) ; water-w i 1 low oak, (Quercus spp.) ; 

and green ash (Fraxinus Marsh) - were hand planted at 11.8 x l,f m, 1.5 x 1.5 m, and 

Experimental design of the plantation was a split-block with five blocks, seven species ,per 

block, and three spacing plots per species plot. 

Species-spacing plots were further divided into 

four, 25-tree measurement replications (five rows with five tree per row). Measurement replications were bordered 3.l m on all sides with trees 

planted at similar spacings. After the first 

growing season, the soil was regularly cultivated 

until crown closure to control competition, 
The second plantation was establish& on an eroded Pidmont upland in Granville County, Xorth 

Carolina, Sails oc this site are a Nhite Store 

clay loam with sloges of 0-5% \;Sawthorn 1970). 

Site preparation began after the original mixed 

hardwd pine forest was harvested and was similar 

to that fsr the boottornlad site, SELings of 

four sI=eir s : EuroLwan black alder, swetgurn, 

loblolly pine and black locust (Robinia 

pseudoacacia L) , were hami9 plant& at 83 x 1.5 m, 

1.5 x 1.5 m and 2,5 x 2-5 m, Experimental design 

of the trial was the same as &he bottomla& except 

that four blocks, ad four species were us&. 

Field Measurments 

All sampling was done during the dormant season (member - January) . Noridestr uct ive smp 

ling of 25-tree replicates 'began following the 

secod growing season fL9bl). Estructive smpling was scheduld at age four armd six years, with 

nondestructive sapling in intervening years, 

During nondestructive sampling years, two out of 

the possible LB rows of measurement trees (from 

each replication) were randomly chosen from each 

species plot in each block. Survival, height 

(nearest 0-83 rn) a& diameter (dbh) to the nearest 

0.3 cm were measurd, Abveground wocxrly biomass was estimated by sampling eight trees per spcies 

from all spacings over the range of tree sizes. 

Trees were chosen by a stratified random sample 

based on diameter, Sample trees were selected 

from border rows at least 3-1 rn from any edge; 

thus, measurement repl icat icns remain4 intact and 

border effects were minlimizd, Sample trees were cut at approximately 5,QI em aboveground with a 

chainsaw and weighed to the nearest Q,@5 kg to 

obtain green weight. Trees were sectione-;d into 

stem and branch (foliage was also separated and 

weighed for lobloliy pine) compnents and weighed. 

Cross-sectional disks approximately 5,@ cm thick were cut from eight sample trees pa: species at 

1/4 and 1/2 total height, Four disks were taken 

from a composite of mdiun diameter branches for 

each tree. A composite random sample of foliage 

from the loblolly pine crowns was also taken. 

Disks and foliage from the? loblolly pine crowns was also taken. Disks and foliage were sealed in 

polyethylene bags and stored at 4'C until processing for moisture and nutrient content, Green 

weights of harvest& sample trees were used to 

develop regression quations. Individual species 

equations were deveio@ each year by plantztion, 

The form of the quation was: 

where: 

Y = whole tree (abvqround green 

biomass in kg 

a S = regression coefficients 

ht = total tree height In m 

dbh - diameter oatside bark at nreast 

height (1-4 rn) in an. 

During destructive sampling years, one of 

four mc3asurement replications was harvestd from 

each spacing plot across all species and blocks, 

and weighed, Biomass yields from each block were averagd by species and spacing. 

Coppice growth and biomass yields were measurd after completion of the seco& growing 

season, Survival, total height of the dominant 

sprout per stool (nearest 0.03 m) and total numJcter 

of coppice sprouts per stool were measured, Cop- pice biomass yields were obtained by harvesting 

sprouts in previously cut measurement replications. To estimate dry weight yields, one 1/2 

height stem disk a& 4 mid length brand disks were cut from eight coppice sprouts over a range of 

sizes. 

Nutrient content of seedling and coppice 

biomass were determined using a sbsiunpling procedure outlined by Messina and others (1983) for 

estimating nutrient content of southern hardwoods. 

Eight trees per species were chosen using the 

sampling method described previously. Sample 

trees were selected from measurement replications 

of medium spacing (1.5 x 1.5 m) for each species 

from one randomly selected block. Combined stemwood and stembark nutrient concentrations for each 

seedling were determined from a single disk taken 

at 1/4 total height. A disk at 1/2 dominant 

sprout height was used for coppice. Branch nutrient concentrations were determined from a composite sample of four disks from medium diameter 

branches. Loblolly pine foliage nutrient concen- trations were determined from a composite needle 

sample (four needle fascicles) taken from the 

upLper, middle and lower third of each sample tree, 

Laboratory Determinations 

After tissue sample green weights were 

determined, samples were oven dried at 70' C to a constant weight. Dry weight biomass was then 

estimated by multiplying the biomass of a component by the appropriate green-to-dry-weight ratio, 

Disk and foliar samples were ground to pass a 0.84 mrn screen. Samples for nutrient analyses were wet-ash4 following procedures described by 

Parkinson and Allen (1979). Total nitrogen (Nf 

and phosphorus (P) were rneasured color imetr icall y as mmonium sal icylate and phosphomolybdenum corn- plexes, respectively on an autoanalyzer. Potassium (K), calcium (Ca), and magnesium (Mg] were deterimined by atomic absorption 

s~tro~rd-totornetry, Tissue samples were analyzed 

in the soils laboratory of the Deprtment of 

Forestry, North Carolina State University. 

Data were analyzed using a split-bloek 

analysis of variance (Steel and Torrie 1980). 

Schef fe's multiple comparison test was used to 

identify significant differences among treatment 

means, ALL tests used a significance level of p = 

(a.95. Statistical analyses were performed using 

the General Linear Models and Means Procedures of 

the Statistical Analysis System (SAS 1985). 
mSIJLTS AM3 DISCUSSION 

Seven-year: biomass yields var id ktwen 

sites and mong species and spacing, Due to high 

mortality, the measurement of black locust was 

diwontinued in 1983, Despite promising early 

grow* on the uplad site, seven-year biomass 

yields of European black alder and sweetgum were 

significantly lower at all spacings compared with 

yields of loblolly pine {Table 1). 

Table 2. Total abovqround ovendry biomass, woad 

and bark for seven-year-old seedlings grown on a 

Coastal Plain red river bottomland in Bertie Co., 

K. 

Spacing (nf 

Species 0.8 x 1.5 1.5 x 1.5 2.5 x 1.5 

Table I. Total abvwround ovcmdry biomass, woud 

and bark for sevewyear-old seedlings grown on a 

nt upland in Granville Co., MG. 

-I--------- (rrrrh-l) ----------_ 

Loblolly pin&/ 50.9 a*2/ 25.8 a+ 21.5 a+ 

Swetgm 5.8 b* 3.7 b* 1.9 b* 

European 

black alder 5.6b* 2.8b* 2.5b* 

L/~ields for loblolly pine include foliage. 

L/~ithin-column yields followed by the same letter 

are not significantly different, and withinrow yields followed by the same symbol are not 

significantly different (~0.05) 

The bttomland site show& higher yields 

eompred to the upland with sycamore, sweetgum, 

European black alder and loblolly pine being 

superior to green ash, cottonwood and water-willow 

oak, except for the green ash at the 2.5 x 1.5 m spacing (Table 2) , 

The poor performance of cottonwood on this 

site was surprising considering its growth in 

adjacent natural stands. The U, S. Department of 

Energy has identified cottonwood, sweetgum and 

sycamore as the most promising SRIC species for 

the Southern United States .(Ranney and others 

1986). 

Eoblolly pine biomass yields were also 

greater than those of European black alder at the 

1.5 x 1,5 m and 2.5 x 1.5 m spacings. Although 

lobloliy pine yields were comparable to hardwoods 

on the bttomland, its survival was only 44, 48 

and 56% for the narrow, medium and wide spacings, 

respectively. Siltation caused pockets of 

mortality in several pine blocks on the 

bttornland. Loblolly pine can survive flooded 

conditions if the water is clear and moving. 

However, clay particles suspended in floodwater 

c.an block the stomata in pine needles. Kellison 

and others (1979) have shown that biomass yields 

of loblolly pine will. surpass yields from southern 

European 

black alder 42.3 b* 24.9 b+ 12.7 b+ 

Loblolly pine L/ 37.4 b* 31.7 a+ 22.7 a+ 

Cot tonwood 25.6 c* 23.6 b* 4.9 b+ 

Water-willow 

oak 15.5 d* 13.0 c* 5.8 b+ 

&/yields for loblolly pine include foliage. 

Z/wi thin-column yields followed by the same letter 

are not significantly different, and withinrow yields followed by the same symbols are 

not significantly dif ferent (p = 0.05). 

hardwood species by age 10, on all sites except 

bottomlands subject to prolonged flooding or 

stagnant water. 

Differences in biomass productivity between 

the bottomland and upland sites were highly 

significant. Seven-year sweetgum yields on the 

bottomland were nine times greater than sweetgum 

yields on the upland at similar spacings (Table 

3). Sweetgum is the most site adaptable southern 

hardwood, but expresses best growth on alluvial 

soils on bottomlands (Kellison and others 1979). 

Averaged over spacings, foliage comprised 

approximately 10 and 12 % of total dry biomass of 

loblolly pine stands on the bottomland and upland 

sites, respctively. Hence, differences in 

biomass production between loblolly pine and 

hardwood species producing greater biomass than 

pine would be even greater if only wood and bark 

are considered . 

Europan black alder yields were seven times 

greater on the bottomland compared with yields on 

the upland (Table 3). Comparatively poor biomass 

yields for European black alder and sweetgum 

likely resulted from their sensitivity to low 

moisture conditions on the uplavd site. Saucier 

(1977) reported that growth and survival of 

European black alder were significantly greater on 

bottomland sites compared with yields on Piedmont 

uplands in Georgia. A further detriment to growth 

of European black alder is its precocious 

flowering habit. After the third growing season, 

flowering had developed at the expense of 
Table 3, Comparison of seven-year seedling 

biomass, wood and bark on a Piedmont upland and 

Coastal Plain red river Sottomland in &rtie Co., 

K (0.8 x 1.5 m spacing). 

biomass prduetivity of natural. southern hardwood 

forests. Messina and others (1986) report an 

average total abovqround kicmass aceu~tiiation 

rate (including f 02 iage) for Southern Coastal 

Plain 'mtto~nland hardwood stands of 4.3 

~rj/ha-l/~r-' at 10 years. 

Coppice Biomass Yields 

-------- (w/ha-l) -------- 

~oblolly pine L/ 5Q.9 &/ 37.4 c 

S~etgum 5.8 b 52.7 a 

European black alder 5.6 b 42.3 b 

&/yields for loblolly pine also include foliage. 

z1wi thin-column yields followed by the same letter 

are not significantly different (p = 0.05). 

vegetative growth on the upland while flowering was less abundant on the bottomland. 

Effects of Spacing on Seedling Biomass 

The effect of spacing on biomass yields for 

both sites varied. On the upland site, only 

loblolly pine yields differed significantly among 

spacings (Table 1). After seven growing seasons, 

biomass accumulations tended to be highest at narrow (0.8 x 1-5 m) spacings. Biornass yields were significantly greater at the narrower 

spacings for all species on the bottomland except 

cottonwood and oak (Table 2). The inverse 

relationship between seedling biomass yields and 

spacing under SRIC has been well documented 

(Steinbeck and May 1971; Wittwer and others 1978). 

Determination of an optional spacing for SRIC 

plantations depends on rotation ages, species and 

site quality. An optimal spacing allows for rapid 

site occupancy and limits mortality from betweentree competition. Analysis of spacing effects on 

seedling mortality indicated that .there were no differences in mortality among species and 

spacings on either site. Although the spacings in 

this study are limited in range, Belanger and 

Pepper (1978) found no relationship between 

stocking (ranging from 200 to 27000 trees ha-'], 

and mortality for six-year-old sycamore seedlings. 

After seven growing seasons, greatest me n ann a1 biomass increment (MAI) was 7.5 Mg/ha-'/ 

yr-ji for sweetgum at 0.8 x 1.5 m spacings on the 

bottomland. Maximum MAI's from this study were low to intermediate compared with the 4.0 to 9.0 

mg/ha/yr given by Hansen and Baker (1979) as the mean annual biomass product ion from SRIC 

plantations in the United States. Some of the 

greater yields found in the literature were found 

in stands which had been heavily fertilized and 

irrigated. Productivity of the best growing 

hardwoods on the bottomland was high compared with 

Two-year bia~tass {wocid and bark) yields were greatest for cottonwood on the bottomland (2.91 

Flg/ha-' at a 1.5 x 1.5 m spacing), and for 

European black alder on the upland (2.91 ~~/ha-l; 

0.8 x 1.5 m spacing) (Table 4)- 

The similarity in coppice biomass production 

between sites was unexpcted considering the significant differences found for hardwood seedling, 

An important attribute of coppice is the potential 

for biomass yields to exceed same aye seedling 

yields by 20 - I@@% (Ranney and others 1985). 

Results from our study support those findings. 

Biomass of two-year-old seedlings for most species 

and spacings on 'both sites. However, on the bottomland, two-year coppice yields for green ash were less than yields for green ash seedlings at 

0.8 x 1.5 and 1.5 x 1-5 m spacings because of deer 

browsing. Coppice yields were at least 80% 

greater than seedling yields for all other species 

and spacings on both sites after two growing 

seasons, Biomass yields were higher at the narrow spacings on both sites, except for cottonwood, 

European black alder and sycamore on the bottomland (Table 4). 

Following seedling harvests, survival was 

at least 85% for most species on both sites. 

Death of coppice stools was a problen for European 

black alder and cottonwood on the bottomland. 

Survival of cottonwood stools was only 34% aver- aged over spacings. European black alder had the 

poorest survival with only 27% averayed over spacings of coppice stools living after the second 

growing season. Survival of European black alder 

coppice stools was poorer on the bottomland (27%), 

compared with the upland (84%), averaged over spacings, Survival of sweetgum stools was also 

lower on the httomland (62%), compared with the 

upland (88%). Prolonged annual spring floods on 

the bottomland during the first and second year of 

coppice growth may have resulted in greater stool 

mortality. 

No significant differences in stool mortality among spacings were found for any species on either site, However, survival tended to be lower 

at narrower spacings for most species on both 

sites. Heilman and others (1972) found siqnificantly greater mortality of Populus trichocarpa 

(Torr. and Gray) with narrower spacings after two 

growing seasons. 

MUTRIENT AEWLATIONS 

Spacing had a large influence on nutrient 

accumulation due to its direct influence on bio- mass production. Highest nutrient accumulations 

tended to be at the narrow spacing for both cop- 
Table 4, Above ground biomass, wood and bark yields of seedlings and coppice grown on a bottomland and 

upland site, 

species spacing 2-~r 2-LT 2-F 2-y~ 

(m) seedllng coppice secrdl ing coppice 

European black alder 

Sweetguan 

Green ash 

Cot tonwood 

oak 

pice and sdlings on both sites (Tables 5 and 6). 

Generally, species producing the most biomass had 

the highest total nutrient accumulat i ons regardless of nutrient concentrations. 

Nutrient concentrations varied with age 

(Tables 7 and 8). For example, sweetgum coppice on the bottomland site had the following nutrient 

concentrations (percent of dry weight wood and 

bark) at two years: N- 0.52; P- 0.07; k- 0.28; 

Ca- 0.43 and Mg- 0.15. Seedling nutrient concen- trations at age seven had decreased to: N- 0.37; 

P- 0.05; K- 0.19; Ca 0.30 and Mg 0.09. Similar 

trends of decreasing nutrient concentrations in 

seedling and coppice biomass with age were 

observtld for most species on both sites. The 

shift towards lower nutrient rich branches and 

bark dereases with increasing age of the tree, 

emrally, nutrient concentrations within a component decrease with age. The exception is for Ca 

in bark (Nessina and others 1986). 

Lower nutrient conentrations and increasing mean annual biomass accumulation lead to greater 

efficiency of nutrient use (utilization efficiency 

= kg of dry biomasshg of nutrient) with age 

(Tables 9 and 1B) , 

On both the upland and bottomland, nutrient 

utilization efficiency of seven-year-old seedlings 

was greater than that of two-year-old coppice. 

The exception was European black alder coppice on the Bottomland which had a higher utilization 

efficiency for P and Mg, Sycamore seedlings 

generally had the highest utilization efficiency 

of all species on the bottomland, except in the case of loblolly pine and Ca. This higher 

efficiency resulted from high biomass accumulation 

and relatively low Ga concentrations for loblolly 

pine on both sites. Relatively lower utilization 

efficiencies for loblolly pine on the upland were due to higher nutrient concentrations com,mred 

with hardwood seedlings. 

Biomass yields of coppice and seedlings 

varied significantly among species, spacing and 

between sites in this study, After seven years, narrow spacings continued to produce greater biomass yields for most species. Mortality annow spacings was not significantly different for any 

species on either site, Spacing-induced competition was not a detectable problem at these ;.ges. 

Therefore, other factors such as increase3 planting costs, harvesting equipment limitations and 

anticipated end use may be more imprtant when 

evaluating SRIC regimes on similar sites, 
Table 5. Nutrient content of 7-year-old seedling and 2-year-old coppice biomass grown on a red river 

bttomland -- Bertie Co., K. 

Nutrient Contents 

Seed 1 i ng Coppice 

Spacing 

species (mf N P K Ca W N P K ca Mg 

Green ash 

Sycamore 

Waterwillow oak 

Cottonwood 

European 

black 

alder 

Table 6. Nutrient content of 7-year-old seedling and 2-year-old coppice biomass grown on a Piedmont 

upland--Granville Co., NC 

Nutrient Contents 

Seed 1 i ng Coppice 

Spacing 

Species (m) N P K Ca MS pJ P K ca Mg 

European 0.8x1.5 

black 1.5x1.5 

alder 2.5x1.5 
Table 7. Nutrient concentration in percentage dry weight of total tree wood and bark for 7-year-old 

seedlings and 2-year-old coppice on a Coastal Plain red river bottmland--3ertie Co., NC. 

species 

SEEDLIS COPP ICE 

N P K Ca Ms N P K Ca p"ry 

Swetgcrm 

Oak 

sycamore 

Green ash 

European 

black alder 

I;oblolly Pine Y 

................................ percentage ----------------------------------- 

.37 -05 -19 .30 .09 .52 .07 .28 .43 .15 

.39 .06 .23 .32 .07 .41 .06 .31 .45 .12 

.26 -05 -19 .21 .05 .58 .07 .20 .32 .08 

L,Data for loblolly pine includes foliage. - 

Table 8. Nutrient concentration in percentage dry weight of total tree wood and bark for 7-year-old 

seedlings and 2-year-old cappice on a Piedmont upland site -- Granville Co., PX. 

SEEDLING COPPICE 

Species N P K Ca M9 N P K Ca % 

.............................. percentage ..................................... 

European 

black alder 

l,Data for loblolly pine includes foliage. - 

Biomass yields of loblolly pine were 

significantly greater than hardwood seedling 

yields at all spacings on the upland site. 

Expensive inputs (i.e. fertilization, site 

preparation and competition control, etc.) 

required for SRIC management of hardwoods on sites 

such as this upland can not be recommended. 

Hawever, SRIC was a relatively productive 

management regime on the bottomland es$ecially 

when compared to natural southern hardwood stands 

growing on similar sites. Sweetgum and sycamore 

are the best species for this and similar sites. 

.Biomass yields of two-year-old coppice were 

greater than that of same age seedlings and 

suggests that coppicing will likely be a successful mode of regeneration. 

Nutrient utilization efficiency increased 

with age and suggests that longer rotations for 

both coppice and seedlings are best. Increasing 

nutrient utilization efficiency occurs as nutrient 

concentrations of biomass decrease and mean annual 

biomass production increases with age. 

This research is supported by the U. S. 

De&prtment of Energy, Short Rotation Woody Crops 

Program through Oak Ridge National Laboratory 

under subcontract No. DE-K01-78C5-84006. 
Table 9. Nutrient utilization efficiencies for 7- 

year-old seedlings and 2-year-old coppice grown 

under short-rotation intensive culture on a Coastal Plain red river bottomland -- Brtie Go,, 

NG. 

Green ash Seedling 294 1665 477 323 1665 

Coppice 176 1145 286 229 763 

Sycamore Seedling 385 2000 526 526 2000 

Coppice 173 1483 494 318 1214 

Water-willow Seedling 256 1667 435 313 1442 

Coppice 241 1551 319 217 1551 

Swetgum Seedling 270 1996 526 333 1112 

Coppice 1963 1488 350 232 661 

Cottonwood Seedling 286 1662 455 278 1113 

Coppice 203 1221 198 185 835 

European Seedling 233 1659 477 303 1665 

black alder Coppice 160 1788 373 298 1788 

~oblolly Seedling 279 1731 426 912 1781 

Pine 

Table 10. Nutrient utilization efficiencies for 

7-year-old seedlings and 2-par-old coppice grown 

under short-rotation intensive culture on a 

Piedmont upland -- Granville Go., NC. 

Sweetgm Seedling 322 2522 716 175 935 

Coppice 258 1750 258 144 829 

European Seedling 257 2545 589 400 1436 

black alder Coppice 146 1712 323 285 1119 

~oblolly Seedling 286 1430 370 588 1430 

Pine 

LITERATURE CITED 

Belanger, R, P, and W, D. Pepper. Seedling 

density influences the early growth of planted 

sycamore. Forest Science 24 (43 : 493-496, 1978. 

Beianger, R, P, and J. R. Saucier, Intensive 

culture of hardwoods in the South, Iowa State 

Journal of Research 49(3):339-344, 1975. 

Cawthorn, J. Soil survey of Wake Co,, W. USDA 

Soil Conservation Service. 1970. 118 p, 

Hansen, E, A. and J. B. Baker, Bimass and 

nutrient reqoval in short rotation intensively 

cultured plantations. In: Proceedings Impact 

of Intensive Harvesting on Forest Nutrlent 

Gycling, SUW College of Enviromental Science 

and Forestry. Syracuse, WZ. August 13-16, 

1979. ,o, 130-151, 

Heilman, I?. E., D. V. Peabody, Jr., D, S. EE11 

and R, F. Strand, W test of close-sped, 

short-rotation culture of black cottonwod. 

Bnadian Journal of Forest Research 2:456-459. 

1972. 

Kellison, R, G,, T. K, Sliehter and D. J. 

Frederick. Matching species to site for 

increased wood production. Tappi. 62(8):77-79, 

1979, 

Messina, M. G., R. Ballard, C, J. Frederick and A. 

Clark 111. A test of a single disk for 

estimation of hardwood bole and branch nutrient 

concentrations. Forest Science, 29:618-626. 

1983. 

Messina, ;";I. G., C. J. Frederick and A. Clark 111. 

Nutrient content and distribution in natural 

southern coastal plain hardwoods, Biomass 

18: 59-79. 1986. 

Parkinson, J, A. and S. E. Allen. A wet oxidation 

procedure suitable for the detemination of 

nitrogen and mineral nutrients in biological 

materials. Soil Science Plant Analysis 

6 (3) : 1-11. 1975. 

Ranney, J. W., P. A. Layton, L. L. Wright and R, 

D. Perlack. Short rotation woody crops progrm: 

Quarterly progress report for July 31, 1986, 

Om Biomass and Municipal Waste l'echnol-y 

Division. Oak Ridge, TN. 1986. 

Ranney, J. W., R. D. Perlack, J. L. Trimble and L. 

L. Wright. Specialized hardwood crops for 

energy and fiber: status, impacts and need. 

Tappi. 68:36-41. 1985. 

SAS Institute Inc. SAS User's Guide: Statistics. 

Cary, NC: SAS Institute, Inc. 956 p. 1985, 

Saucier, 3. R, Growth and survival of European 

black alder and sycamore on upland and 

bottwnland sites . USDA Forest Service Research 

Mote. SE-248, 1977. 6 pp. 

Steel, 9, G. D. and J. H. Torrie. Principles and 

Procedures of Statistics. 2nd. ed. McGraw Hill. 

New York, NY. 1977 633 pp. 

Steinbeck, K, and J. T. May. Productivity of a .rery young Platanus oecidentalis planting grown 

at various spacings, In: Forest Biomass 

Studies, Section 25, Growth a& yield. 15th 

TUFRO Congress. 1971, p. 153-162. 

Wittwer, R. F., R. FI. King, J. M, Clayton and 0, 

We Hinton. Bimss yield of short-rotation 

Arnerican sycamore as influenced by site, 

fertilizers, spacing and rotation age, 

Southern Journal of Applied Forestry 2:15-l9. 

1978, 
Pine-Hardwood Regeneration 

Moderator: 

Robert Zahner 

Clernson University 

SILVICULTURkL IMPLICATIOi<S OF MIXED PIliE-HARDWOOD 

STANDS IN THL PIEDNONT~/ 

Herbert A. Knight and Douglas R. I?hillip&/ 

Abstract.--In the Southesst Piedmont, almost 5.6 

million acres, or 21 percent, of the forests are 

mixed stands containing 25 to 75 percent hardwood and 25 to 75 percent pine, Analysis of 

forest survey plot dhta indicates that yield in 

these stands varies with the proportion of pine 

present. 

Keywords: Timberland, Southeast Piedmont, mixed 

pine-hardwood stands. 

INTRODUCTION 

Nany of the timber stands on the Piedmont 

Plateau of the Southeastern United Stctes are 

mi:;tures of pines and hardwoods. This paper 

qu~ntifies and describes the full rznge of mixea 

pine-hardwood stands and examines their yields. 

Sandwiched between the Southern Appalachian 

Mountains ana the So~th Atlantic Coastal Plain, 

the Southeast Piedmont, extends from northern 

Virtinia to west-central Georgizi (fig. 1). 

Delineations of this region vary among different 

geographic61 classifications. As defined here, 

the region comprises 6 of the 21 forest survey 

units the USDA F'orest Service inventories in the 

Southeast (Larson and others 1961). This delineztion includes most of the area that Austin 

(1965) designated as the Southern Piedmont,, 

The Southeast Piedmont contains almost 44 

million acreE of land, most of which is best 

characterized zz g~ntly rolling upland. Generally, the elevktion ranges from about 500 to 

1,000 feet, and increases gracually from ezst to 

west. Exceptions are the mountsins in upstste 

South C~rclinz and some higher foothills alonb 

thz eesterz, side of the Southern Appalachians. 

Numerous "rea waterff rivers and streams carrying 

heavy silt loads flow through the region (Stubbs 

1966). The floodplains of these streams are best 

characterizes as bottom land. The ratio of 

u~land to bottom lend is about 7 to 1. 

.!./presented zt the Fourth Biennial Southern, 

Silvi~ulitur~l Research Conference in Atlanta, 

Georgia, ori Nove~ber 4-6, 1986. 

z/./~esource Anz.lyst, USDB Forest Service, 

Southeastern Forest kxperiment Ststion, Asheville, 

IdC 288134; and Prir?cipc?l Mensurationist, USDA 

Forest Service, Southezstern Forest Experi~cnt 

Station, Cienson University, Clemsor, SC 

29634-9940. 

Figure 1.--The Southeast Piedmont. 

THli; TIMBEIi RESOURCE 

Since settlement, most of the ~planci an& rtiuch 

of the bottom land has been in anc out of timoer 

production one or more times (Boyce and Knignt 

1979 and 1480). Currently, forests occupy 42 

percent of the land in the rebion. Almost 27 

million zeres, or 99 percent of these forests, 

are classed as timberland. The sr,,all remainder 

is withdrawn froa timoer utilization tbrougn statute or aaministrative Cesi,nation ana reservec 

for other us?:. Hzrawoccs clezrll dominate Dottoill lanci forest: zi:L ir, the aoser~cc of fire ar~a 

mar,'s intervection, ;ardkrooas tcnc to cominate 

pints on uplanc icrests. Auout nclf of tne 

tin,b~rl;ncl r-elc 03. sxall no,,inaustrizl yriv&te 
landowners supports hardwood stands (Bechtold Table 1.--Area of tirilberland in the Southeast 

and Phillips 1983). Even on timberland owned or Piedmont, by stana-age class, by pine stocking 

leased by forest industry, pines dominate the percent 

stocking on less than 60 percent of the land, 

When all owners are grouped, pine stocking exceeds 

the stocking of hardwood on Less than 40 percent Stand-age 811 Pine stocking percenta 

of the existing timberland in the Southeast 

Piehont . class stands Less than 

(years 1 25 25-49 50-74 75+ 

The pine-hardwood mix varies greatly by stand 

age (table I), Pine exceeds hardwood stocking in 

more than half of the stands 11 to 40 years old. 

The larger mount of pine in stands of these ages 

reflects extensive reversion of cropland and 

pastureland to pine forest between 1940 and 1970. 

In 1940, more than 20 million acres in the Southeast Piedmont were classed as either croplana or 

pastureland. By 1970, fewer than 12 million 

acres were used for these purposes. The natural 

and artificial establiskent of pine trees on 

most of the acres taken out of agricultural use 

resulted in a net increase in area of timberland 

from 22 to 28 million acres over this same 

30-year period, Urban expansion, new roads, 

highways, and reservoirs accountea for most of 

the remaining diverion from agricultural use. 

From 1940-1970, the widespread establishment of 

pine on former agricultural land tended to @ompensate for hardwood encroachment following the 

harvesting of pine, Pine volume as a percent of 

total volume stabilized at about 42 percent (fig. 

2). In the absence of extensive reversion of 

agricultural land to pine timber since 1970, the 

pine component of the resource has dropped to 

below 40 percent. 

- - - - - Thousand acres - - - - - 

00- 10 4,1124 1,673 703 370 1,678 

1 1-20 3,751 1,322 474 386 1,569 

21-30 3,921 1,188 38G 447 1,902 

3 1-40 4,637 1,927 577 452 1,675 

11 1 -50 3,879 2,196 462 466 755 

51+ 6,369 4,812 632 401 524 

Total 26,975 13,118 3,232 2,522 8,103 

aPine stocking as a percent of all live tree 

stocking in the stand. 

Other than fire protection, most investments in 

forestry and improved silvicultural practices in 

the Southeast Piedmont over the past 50 years 

have been made to favor pines. Most silvicultural 

investments have been in such practices as site 

preparation, artificial regeneration, and various 

kinds of hardwood control, Still, these practices have not reversed the strong successional 

trend toward hardwood in the region. Except on 

old-field sites, it is difficult to establish and 

maintain pure stands of pine in the Southeast 

Piedmont. Even In existing stacas kith evidence 

of artificial regmeration, there &re significant 

amounts of hardvoot. Pines account for 75 percent or more of the stocking in fewer than 80 

percent of the plantations. Pines account for 75 

percent or more of the stockin& in fewer than 70 

YEARS 

PERCENT 

Figure 2.--Pine volume as a percent of total 

volume in the Southeast Piedmont. 
percent of the plantations less than 10 years old 

(table 2). Perhaps mixed pine-hardwood stands 

are the most affordable compromise for managed 

upland stands in which hardwoods have become well 

established, 

Table 2.--Area of timberland in the Southeast 

Piedmont with evidence of artificial regeneration, 

by stand-age class, by pine stocking percent 

Pine stocking percenta Stand-age 811 

class stands Less than 

(years 2 5 25-49 50-74 75-1- - 

- - - - - - Thousand acres - - - - - - 

00-10 1,534 8 0 219 167 1,068 

I1 -20 766 8 25 84 649 

2 1-30 643 7 -- 27 609 

3 I+ 1 32 4 -- 11 117 

Total 3,075 99 244 289 2,443 

need some measure of the yields in these mixed 

stands relative to yields achieved in pure 

stands. Although the Forest Survey is neither 

designed nor intended to provide conventional 

growth and yield data, it does provide measures 

of stand perfomance across the broad range of 

sites, stocking levels, and forest conditions 

within the region. Average volumes per acre are 

presented by stand-age class and by pine stocking 

class in tables 3 and 4. These averages are 

based on measurements taken on 1,450 sample plots 

distributed in timberland throughout the Southeast Piedmont, Since these averages do not 

reflect differences among sites and stocking 

levels, they differ from published empirical 

yields developed from Forest Survey data (McClure 

and Knight 1984). 

Table 3,--Average volume of growing stock per 

acre of timberland in the Southeast Piedmont, 

by stand-age class, by pine stocking percent 

aPine stocking as a percent of all live 

stocking in the stand. 

- 

Pine stocking percenta Stand-age All 

class stands Less than 

(years) 2 5 25-49 50-74 754- 

Mixed Pine-Hardwood Stands 

The most recent forest surveys show 3.2 million 

acres, or 12 percent of the region's timberland, 

as oak-pine forest type. These are forests in 

which hardwoods constitute a plurality, but in 

which pines account for 25 to 50 percent of the 

stocking. Hardwoods account for 25 to 50 percent 

of the stocking on 2.5 million additional acres 

classed as pine types, Altogether, more than 5.7 

million acres, or 21 percent of the timberland, 

support timber stands best characterized as mixed 

pine-hardwood (table 1). This percentage does 

not vary greatly by stand-age class up through 

age 50. 

The species composition of these mixed stands 

varies. Loblolly pine (Pinus taeda L.), shortleaf pine (Pinus echinata Mill.), and Virginia 

pine (Pinus virginiana Mill,) account for almost 

95 percent of the total softwood volume. 

Loblolly alone accounts for 58 percent, followed 

by shortleaf with 20 percent and Virginia with 16 

percent, 

Together, a wide variety of oaks (Quercus spp.) 

account for 40 percent of the hardwood volume in 

these mixed stands, Among these, white oak 

(Quercus alba L,) predominates and accounts for 

about 11 percent of the total hardwood volume. 

Other than oaks, the two leading hardwood species 

in these mixed stands, are sweetgum (Liquidambar 

L,) and yellow-poplar (&iriodendron 

L,), accounting for 21 and 17 percent, 

respectively. 

- -------Cubicfeet------- 

00-10 180 244 256 149 92 

1 1-20 607 545 580 565 678 

21-30 1,282 87 9 976 1,250 1,603 

3 1-40 1,637 1,412 1,337 1,688 1,986 

4 1-50 1,982 1,806 1,827 2,280 2,404 

51+ 2,161 2,112 2,055 2,449 2,519 

"Pine stocking as a percent of all live tree 

stocking in the stand. 

Table 3 clearly shows that average volume of 

growing stock per acre increases as pine stocking 

percent increases, assuming no significant difference in average site and stocking, This 

correlation is particularly evident in stands 

where pines account for 25 percent or more of the 

existing stocking of all live trees. For example, in the 21- to 30-year age class, average 

volume per acre in stands where pines account for 

75 percent or more of the stocking is 64 percent 

greater than the average in stands where pines 

account for 25 to 49 percent of the existing 

stocking. It is 28 percent greater than the 

average in stands where pines account for 50 to 

74 percent of the existing stocking, 

The largest differences in average volume per 

acre by pine stocking percent are in the 21- to 

30-year age class. As stand age increases, the 

diiferences diminish. Although not presented, 

the same correlations hold when average volume 

per acre is calculated for all live trees 5.0 

inches and larger in diameter at breast height 

(d.b.h.) rather than for growing stock alone. 

Distribution of the additional volume in rough 

and rotten hardwood trees does not alter the 

conclusion that average volume per acre increases 

as pine stocking percent increases, 

Faced with the reality and persistence of these 

mixed pine-hardwood stands, timberland managers 
Similar averages are presented for the 

sawtimber portion of growing stock expressed in 

board feet (table 4). Again, the sane correlations as found in cubic volume per aere are 

evident. One additional factor to Keep in mind 

while interpreting the differences in average 

board-foot volume per aere is a key aifference 

in merchantability standards between pine and 

hardwood, For pines, board-foot volume is 

assigned to growing-stock trees 9.0 inches d.b.h. 

and larger; for hardwoods, board-foot volume is 

assigned to growing-stock trees 11,O inches 

d.b.h, and larger. 

Table 4.--Average volume of sawtimber per acre of 

timberland in the Southeast Piedmont, by standage class, by pine stocking percent 

Stand-age All Pine stocking percenta 

class stands Less than 

(years 25 25-49 50-74 75+ 

- - - -- - - - 

aPine stocking as a percent of all live tree 

stocking in the stand. 

b~nternational 1 /4-inch rule. 

Other significant measures are differences between the proven yields in planted stands and 

natural stands. Average volumes per acre were 

developed for stands with evidence of artificial 

regeneration, by stand-age class, by pine 

stocking percent (tables 5 and 6). Most of the 

samples were in stands 30 years old and younger, 

In comparing these averages with those in tables 

3 and 4, readers should be aware of several factors affecting the differences: (1) The averages 

for natural stands reflect a significant amount 

of volume in older residual trees left during the 

previous harvest. (2) Artificial regeneration 

would tend to result in higher pine stocking than 

natural regeneration, except possibly on old 

fields. (3) Most of the older pine plantations 

were established with regular planting stock. 

Genetically improved planting stock available 

today will boost yields by 10 to 15 percent. 

All of these factors would tend to underestimate the real differences in yields between 

planted and natural stands. For example, the 

20-percent higher estimate for planted stands 20 

to 30 years old which are 75 percent or better 

stocked with pine in table 5 compared with the 

same average in table 3 is probably a conservative difference. As with natural stands, the 

average vol~es per acre increase as pine 

stocking percent increases for ages 11 through 30. 

Table 5.--Average volume of growing stock per 

acre of timberland in the Southeast Piedmont with 

evidence of artificial regeneration, by stand-age 

class, by pine stocking percent 

Stand-age All Pine s;ocking percenta 

class stands Less than 

(years 2 5 25-49 50-74 75+ 

31+ 2,535 3,041 -- 2,716 2,502 

aPine stocking as a percent of all live tree 

stocking in the stand. 

Table 6,--Average volume of sawtimber per acre of 

timberland in the Southeast Piedmont with evidence of artificial regeneration, by stand-age 

class, by pine stocking percent 

- - - - - - -- 

Stand-age All Pine stocking percenta 

class stands Less than 

(years ) 2 5 25-49 50-74 75+ 

00-10 35 26 7 9 67 21 

1 1-20 57 6 349 543 806 551 

21-30 4,943 738 -- 3,285 5,067 

3 1 + 9,534 11,242 - - 11,094 9,331 

aPine stocking as a percent of all live tree 

stocking in the stand. 

b~nternational 1 /4-inch rule, 

SILVICULTURAL IMPLICATIONS 

The analysis of existing mixed stands has shown 

that stand yields increase as the pine component 

increases and as management moves from natural to 

artificial regeneration. These trends are broad 

generalizations across all sites and are not 

easily dissected for exact interpretation. 

Differences could be due largely to differences 

in stand stocking and merchantability limits between pines and hardwoods. However, even with 

similar levels of stocking and mer~hant~bility 

limits, the pine component would be expected to 

produce higher solid wood volumes because pines 

grow faster than most hardwoods and because pines 

concentrate more of their growth on the sain stem, 

The higher yields of plantations, as compared with 

natural stands, can be traced to better stocking 

and to genetically improved seedlings. 

In looking to the future, there are two sigr~ificant trends occurring in the Piedmont that will 

affect future management strategies, One, the 

number of pine plantations is increasing and two, 

the hardwood component in these plantations is 

increasing, In 1986, successful plantations 
account for more than 10 percent of the timberland in the Southeast Piedmont, compared with 7 

percent duping the previous survey (Phillips 

1983). In stands younger than 10 years old, 

plantations account for 28 percent of total timberland. This is a significant increase over 

past decades. 

Matching the increase in plantation acreage is 

a corresponding increase in the hardwood component in these stands. Pines account for 75 

percent or more of the stocking in about 80 percent of all plantations, but represent a 75 percent plurality in fewer than 70 percent of 

plantations younger than 10 years old. These 

young mixed stands are different than their counterparts because of the way they started. In 

prior years, many plantations were established on 

old fields where hardwood competition was minimal 

or nonexistent. The plantations of the last 10 

years have been established primarily on sites 

where hardwoods make up a significant component 

of the stand, These new stands provide a 

challenge in that more decisions must be made 

regarding hardwood control. Because of the 

wildlife and esthetic benefits of mixed stands, 

many managers would not eliminate hardwoods even 

if they were convinced that overall productivity 

would improve. 

If we assume overall productivity does improve 

with the reduction of hardwoods through release, 

does the increased pine production justify the 

cost of release? What are the yields and comparative values of young even-aged mixed pinehardwood stands? These questions are beyond the 

scope of this paper, but, as the trends indicate, 

we must begin to evaluate our mixed stands if we 

are to make intelligent management decisions 

about a significant portion of the resource. 

LITERATURE CITED 

Austin, Morris E. Land resource regions and major 

land resource areas of the United States. 

Agric, Handb, 296. Washington, DC: U.S. 

Department of Agriculture, Soil Conservation 

Service, 1965. 82 pp. 

Bechtold, William 8.; Phillips, Douglas R. The 

hardwood resource on nonindustrial private 

forest land in the Southeast Piedmont, Res, 

Pap. SE-236. Asheville, NC: U.S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1983. 19 pp. 

Boyce, Stephen 6.; Kni~ht, Herbert A. 

Prospective ingrowth of southern hardwoods 

beyond 1980. Res. Pap. SE-203. Asheville, NC: 

U,S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1980. 

33 PP. 

Boyce, Stephen G.; Knight, Herbert A. 

Prospective ingrowth of southern pine beyond 

1980. Res. Pap. SE-200. Asheville, NC: U.S, 

Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1979, 

48 PP* 

Larson, Robert W.; Nichols, Agnes C.; Goforth, 

Marcus H. Timber trends in the Southeast. 

For, Survey Release No. 58. Asheville NC: U,S, 

Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1961. 

16 PP. 

McClure, Joe P.; Knight, Herbert A. Empirical 

yields of timber and forest biomass in the 

Southeast, Res. Pap. SE-245. Asheville, NC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1984. 

75 PP. 

Phillips, Douglas R. Piedmont hardwoods: A 

forgotten resource. In: Proceedings, Eleventh 

annual hardwood symposium of the Hardwood 

Research Council; 1983: May 10-13; Cashiers, 

NC, 1983:148-155. 

Stubbs, Jack. Hardwood type-site relationships 

on the Coastal Plain. In: Proceedings, 1966 

Symposium on hardwoods of the Piedmont and 

Coastal Plain; 1966 October 26-27; Macon, GA: 

Georgia Forest Research Council; 1966:lO-12. 
GROWTH AND DEVELOPlilENT OF SHORTLUF PINEMIXED STmDS FOUR YEARS AFTER REGENERATION- W?9" 

Douglas R. Phillips and 2 / James A. Abercrombie, Jr.- 

Abstract.--Three four-year-old shortleaf pine-hardwood 

mixed stands were inventoried in the winter of 1985. The 

stands had been established on the Sumter National Forest 

through low intensive site preparation that involved spring 

chainsaw felling of residuals and summer burning. Results 

show that 304 to 414 of the 454 planted pines per acre were 

free-to-grow after 4 years. Average total height of the 

pines was 7.9, 8.4 and 9.3 feet in the three stands. Corresponding average total heights for hardwoods was 5.8, 4.9, 

and 4.7 feet. These mixed stands are well stocked with 

pines and commercially important hardwoods and thus have 

high timber value potential. They also can provide many 

nontimber benefits. 

INTRODUCTION 

The Piedmont and mountain regions of the Southeastern United States contains 40 million acres 

of commercial forest land, 4.6 million acres of 

which is classed as the oak-pine type. In the 

Piedmont, an additional 2.5 million acres classed 

as pine contain 25 to 50 percent hardwoods and 

thus could be considered as mixed stands @night 

and Phillips, 1986). These mixtures developed 

primarily as the result of selective harvesting 

of pines and encroachment of hardwoods into pine 

stands. Between 1944 and 1964, large acreages of 

cropland were abandoned in the Piedmont to the 

seeds of pine trees (Krause 1970). These stands 

developed into almost pure pine stands because 

the root stocks of sprouting hardwoods were not 

present. As these stands developed throughout 

the sixties and seventies, many of the merchantable pines were harvested. Hardwoods waiting in 

the understory took over and grew along with the 

small pines that were left behind. The recent 

trend has definitely been toward more hardwood 

and less pines in our southern forests (Boyce and 

Knight 1979, 1980). 

As mixed stands are harvested, landowners find 

that they must spend large sums of money to convert them back to pure pine. Many owners choose 

not to make this investment, and as a result, the 

trees. Since pure pine regeneration is so costly 

and pine management fails to provide many nontimber benefits (firewood, habitat for hunting, 

recreation, and aesthetics), landowners often opt 

to do nothing in favor of spending $200 or more 

per acre to get a pure pine stand. Forest survey 

statistics show that in spite of concerted efforts 

to increase the acreage of pine plantations, only 

10 percent of commercial timberland in the 

Piedmont and 2 percenta in the mountains is in 

plantation management (Knight and Phillips, 1986). 

An alternative to pine plantation management is 

the culturing of pine-hardwood mixtures. Mixed 

stands can provide the nontimber benefits landowners desire, and regeneration can be achieved 

at approximately half the cost of conventional 

pure pine management. The approach requires careful scheduling of stand treatments, but much of 

the work can be done by the individual owner. 

This paper describes the growth and development 

of mixed stands of shortleaf pine (Pinus echinata 

Mill.) and hardwoods established through low 

intensity site preparation techniques that involves chainsaw felling of residuals and summer 

burning. 

METHODS 

new stands are less than adequately stocked and Study Sites 

frequently dominated by noncommercial or damaged 

- 1 / 

Paper presented at Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

Sample plots were established in three stands 

on the Andrew-Pickens District of the Sumter 

National Forest in upstate South Carolina. The 

three stands, hereafter referred to as Sandy Ford, 

Whetstone, and Pine Mountain, had similar characteristics: each had a southern exposure, an 

elevation of approximately 1500 feet, and a 

- 2 / 

Principal Mensurationist, USDA Forest Service, 

Southeastern Forest Experiment Station, Clemson 

University, Clemson, SC 29634, and Timber Manage- a Personal comunications with Herb Knight, 

ment Assistant, USDA Forest Service, Sumter Renewable Resource Evaluation Unit, Southeastern 

National Forest, Walhalla, SC 29691. Forest Experiment Station, Asheville, NC. 
pine-hardwood overstory. Based on available but 

less than desirable site trees, site index was 

estimated to be 60 to 70 for shortleaf pine at 50 

years. Soil samples were taken at each site to 

refine site productivity estimates. The soii at 

Sandy Ford is Saluda series, a loamy, mixed, 

mesic, shallow Typic Hapludult. Solum depth (A 

and B horizons) is 16 to 20 inches. The soil at 

Whetstone is Evard, a loamy, oxidic, mesic Typic 

Hapludult. Solum depth is 28 to 32 inches. The 

soil at Pine Mountain is Walhalla, a fine-loamy, 

oxidic, mesic Typic Hapludult. The Malhalla 

solum is 40 to 49 inches deep. 

In the winter of 1980, each stand was coxmercially harvested. Sandy Ford yielded 320 cubic 

feet per acre (CFfac) of small pine roundnood 

(5.0 to 12.0 inches d.b.h.1 and 340 CF/ac of 

small hardwood roundwood (6.0 to 14.0 inches 

d.b.h.), Whetstone yielded 7.8 thousand board 

feet per acre (MBF/ac) of pine sawtimber, 0,5 

MBF/ac of mixed hardwood sawtimber, 310 CFlac of 

small pine and 390 C~/ac of mixed hardwood roundwood. Pine Mountain produced 3.0 MBF/ac of pine, 

0.2 MBF/ac of mixed hardwoods, 200 CF/ac of small 

pine roundwood, and 300 CF/ac of small mixed 

hardwood roundwood. Almost all of the pines on 

all sites were shortleaf pine. The most numerous 

overstory hardwoods were red oaks (Quercus spp.), 

white oaks (Quercus spp.) and hickories (Carya 

spp.). Following commercial clearcutting, the 

stands were opened to the public for firewood 

salvage. The removal of trees for firewood not 

only assured full utilization, but reduced site 

preparation costs. In late spring after residual 

stems were fully leafed out, they were felled 

with chainsaws. The felled residuals, along with 

tops and other logging debris from the harvesting 

operation, provided the needed fuel for a late 

summer burn (Abercrombie 1984). Dry leaves and 

branches of felled residuals were needed to carry 

a hot surface fire over a fuel bed too moist to 

support combustion. By burning when the soil was 

moist, some of the organic layer and most of the 

incorporated root mat was maintained (Danielovich 

1986). This limited erosion which over time should 

help maintain site productivity. 

The following winter (1981), approximately 454 

genetically improved shortleaf pine seedlings 

were planted at a spacing of 8 x 12 ft. No other 

treatments were applied. 

Four growing seasons after treatment (the winter 

of 198Sj, the three stands were inventoried to 

determine species composition, density, and growth 

of pines and hardwoods. Stem basal diameters in 

inches and total-tree heights in feet were tallied 

fur planted shorrleaf pines that remained free to 

grow (those receiving full sunlight from above) 

after I years, These trees were on six 52.5 x 52 

ft plots spaced 16.4 feet apart and arranged in a 

2 x 3 matrix with the long sxis running east and 

west along the slope. Hardwood regeneration and 

naturally seeded shortleaf pines were measured on 

three 10- x 120-ft strips spaced approximately 90 

feet apart and perpendicular to the slope of each 

stand. Total heights of ail live trees > 2.0 feet 

tall were tallied in feet by species. With sprout 

clumps of more than one stem, minor suppressed 

stems in the clump were not counted. 

RESULTS 

A total of 643 planted shortleaf pines were 

measured at three locations. On a per-acre basis, 

304 to 414 trees were free to grow after 4 years. 

Those values translate into planting success rates 

of 71 to 91 percent. At Sandy Ford, the 304 

planted pineslacre that were not overtopped 

averaged 1.6 inches in diameter outside bark 

(d.0.b.) at groundline and 7.9 feet tall. Whetstone had 356 free-growing pineslacre with an 

average goundline d.0.b. of 1,8 inches and an 

average total height of 8.4 feet. Pine Mountain 

had 414 free-growing pineslacre with an average 

groundline d,o.b. of 2.2 inches and an average 

height of 9.3 feet (Table 1). 

The hardwood components at the three study sites 

differed considerably in numbers and species composition. Sandy Ford was dominated by oaks 

(1,945 trees/ac), with substantial amounts of 

blackgum, hickory and sourwood. Mhetstone had a 

large oak component (1,409 trees/ac), a large 

amount of blackgum, and a variety of other hardwoods. Pine Mountain had very little oak (298 

treeslac) but significant amounts of blackgum, 

yellow-poplar and noncommercial hardwoods (Table 

2). The noncommercial group at Pine Mountain was 

dominated by sumac (Rhus glabra L.) with 922 

trees/ac. Sandy Ford had the most total hardwoods 

with 4,898 treesfac while Whetstone had 4,400 

treeslac and Pine Mountain 3,627 treeslac. 

Table 1. Characteristics of 643 four-year-old shortleaf pine crop trees sampled at three locations 

Basal diameter Total height 

Trees 

Locat ion sampled Treeslac Mean St. dev. range Xean St. dev. range 

------ Number------- ------me- inches----------- -----------feet----------- 

Sandy Ford 182 304 1.6 0.5 0.7-2.8 7.9 1.8 3.5-12.4 

Whetstone 213 356 1.8 0.6 0,7-3.4 8.4 2.0 3.3-13.2 

Pine Mountain 248 414 2.2 0.5 1.0-3.6 9,3 2.0 4.6-14.1 
Table 2. Nuder of sprout clumps per acre, trees per acre, trees per cluartp and average total 

tree height of hardwoods by species and location four years after regeneration. 

Average total 

Speciesa Clumps / ae Treeslac Trees/clump tree heightb 

Scarlet oak 

Southern red oak 

White oak 

Post oak 

Other oaks 

Blackgum 

Red maple 

Yellow-poplar 

Hickory 

Sourwood 

Other hardwoods 

All hardwoods 

Scarlet oak 

Southern red oak 

White oak 

Post oak 

Other oaks 

Blackgum 

Red maple 

Yellow-poplar 

Hickory 

Sourwood 

Other hardwoods 

All hardwoods 

Scarlet oak 

Southern red oak 

White oak 

Post oak 

Other oaks 

Bl ackgum 

Red maple 

Yellow-poplar 

Hickory 

Sourwood 

Other hardwoods 

All hardwoods 

SANDY FORD 

WHETSTONE 

125 

424 

498 

212 

150 

1,259 

125 

87 

150 

2 12 

1,158 

4,400 

PINE MOUNTAIN 

a Scarlet oak (Quercus coccinea Muenchh.), southern red oak (9. falcata Michx.), white oak (Q. 

alba L.), post oak (Q. stellata Wangenh.), other oaks (Q. spp.), blackgum (Kyssa sylvaticc 

Marsh.), red maple (Acer rubrum L,), yellow-poplar (Liriodendron tulipifera L.), hickory 

(Carya Nut t . spp . ) , sourwood (- arboreum L. ) . 

Height of tallest tree in the clump if more than one stem. 

Average number of trees/clump ranged from 1.0 

for post oak at Whetstone to 3.5 for sourwood at 

Sandy Ford (Table 2). Average number of trees/ 

clump for all hardwoods at the three locations 

ranged from 1.3 to 1.7. Averages, in this case, 

can be misleading. Many species, especially the 

oaks, had numerous sprout clumps of 3 to 5 trees/ 

clump but a high number of individual stems that 

lowered the average. 

Weight of all hardwoods at Sandy Ford averaged 

5.8 feet compared to 4.9 feet at Whetstone and 4.7 

feet at Pine Mountain (Table 2). As a group, the 

hardwoods were substantially outperformed by 

planted shortleaf pines (average total height at 

Sandy Ford was 7.9 feet, at kletstone 8.4 feet, 

and at Pine Mountain 9.3 feet). However, certain 

hardwood species performed better than others. 

Sourwood averaged approximately 7.0 feet in total 
height at Sandy Ford and Whetstone and 8.2 feet 

at Pine Mountain, and red maple averaged 10.2 

feet in total height at Pine Hountain. These 

are not desirable timber species and provide the 

most serious competition to pines and desirable 

hardwoods. Fortunately, their numbers were 

small . 

In addition to planted shortleaf pines and 

naturally regenerated hardwoods, a certain component of naturally seeded shortleaf pine was 

found on the three sites. The number of treeslac 

ranged from 37 to 75 and average total height 

ranged from 3.5 to 5.6 feet (Table 3). Although 

these pines were shorter than their planted 

counterparts and many hardwoods, they may contribute to the future stand because they occurred 

mostly in openings in the stand. 

Table 3. Number of naturally seeded shortleaf 

pineslac at three locations four years after 

regeneration. 

Locat ion Treeslac Total height 

Sandy Ford 5 0 

Whetstone 3 7 

Pine Mountain 75 

SUMMARY AND CONCLUSIONS 

After 4 growing seasons, shortleaf pinehardwood mixed stands developed through low intensive site preparation and burning are 

beginning to show real promise. Planted pines 

are averaging 7.9 to 9.3 feet in height and 1.6 

to 2.2 inches in basal diameter. Competing 

hardwoods are not as tall, but many oaks and 

other commercial hardwoods are well developed 

and should contribute to the final stand. With 

new technology leading us toward increases use 

of hardwoods (Ince 1986), low cost regeneration 

techniques that allow hardwoods to develop with 

pines make good sense. Landowners need low cost 

regeneration alternatives such as this and many 

place high value on the nontimber benefits these 

stands can provide. 

LITERATURE CITED 

Abercrombie, J. A., Jr. 1984. Spring chainsaw 

felling and summer burning for pine site 

preparation in the Ouachita and Southern 

Appalachian Mountains. Andrew Pickens Ranger 

District, Sumter National Forest, SC. 3 p. 

Boyce, S. G. and H. A. Knight. 1979. Prospective ingrowth of southern pine beyond 1980. 

U. S. Dep. Agric. For. Serv., Res. Pap. SE200, 48 p. Southeast. For. Exp. Stn., 

Asheville, MC. 

Boyce, S. G, and H. A. Knight. 1980. Prospective ingrowth of southern hardwoods beyond 

1980. U. S. Dep. Agric. For. Serv., Res. Pap. 

SE-203, 48 p. Southeast. For. Exp. Stn., 

Asheville, NC . 

Danielovich, S. J. 1986. High intensity site 

preparation burning after clearcutting in 

southern hardwoods -- effects on residual vegetation and soil erosion. Thesis. May 1986, 

Clemson Univ., Clemson, SC. 67 p. 

Ince, P. J. 1986. Technology development for 

increased use of hardwoods. In proc. of 

Fourth Biennial Southern ~ilv?.<ural Res . Conf., Atlanta, GA. Nov. 4-6, 1986. 

Krause, D. E. 1970. Cropland trends since World 

War 11. Regional changes in acreage and use. 

USDA Econ. Rpt. 177. Washington, DC. 15 p. 

Knight, H. A. and D. R. Phillips. 1986. Silvicultural implications of pine-hardwood mixtures 

in the Piedmont. In proc. of Fourth Biennial 

Southern ~ilvicult~al Res. Conf . , Atlanta, 

GA. Nov. 4-6, 1986. 
COPPICE REGENERATION IF; THE OAK-PINE TYPE RELATIVE TO INITIAL 

1 / 

SPECIES COMPOSITION, STAND STRUCTUm, AND SEASON OF FELLING2 / 

James W, McMinnAbstract.--Oak-pine stands in the Upper Piedmont of 

Georgia were harvested with feller-bunchers in both the 

dormant season and early growing season to 1-inch and 4-inch 

lower diameter limits. The initial hardwood component was 

comprised primarily of scarlet oak (Quercus coccinea 

Muenchh. ) , post oak (9. stellata Wangenh. ) , black oak (Q. 

velutina Lam.), chestnut oak (Q. prinus L.), southern red 

oak (Q, falcata Michx.), hickory (Carya spp.), blackjack oak 

(2. marilandica Eluenchh.), sourwood (Oxydendrum arboreum 

(L.) DC.), white oak (9. alba L.), dogwood (Cornus florida 

L.), and blackgum (Nyssa sylvatica ~arsh.), respectively, as 

indicated by basal area. Analysis of variance was employed - - 

to test the influence of species, as well as season of 

felling, degree of stand removal, and their interactions on 

5-year coppice growth. Five years after the 4-inch-limit 

harvest, coppice coverage per square foot of initial stand 

basal area was only 41 percent as great as after the 1-inch 

limit harvest. Species predominance in the 5-year coppice 

stand differed substantially from the initial stand due to 

species differences in coppice regrowth per square foot of 

initial basal area. 

INTRODUCTION 

This study was motivated by the potential for 

using intensive whole-tree harvesting as a 

silvicultural tool (Butts and Preston 1979). 

The general objective was to compare the effects 

of season and intensity of whole-tree harvesting 

on subsequent stand development in mixed 

hardwood-pine associations of the Upper 

Piedmont. An earlier paper presented the 

effects of the treatment variables on total 

sprout coverage and its relation to pine regeneration through the fourth growing season 

(McMinn 1985a). The original study was not 

designed to test differences in coppicing among 

species or the interactions of species with the 

harvesting variables. Nevertheless, such a test 

was devised, and this paper presents results 

based on the 5-year-old coppice component. 

1 I -' Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986, 

- 2 1 

Research Forester, USDA Forest Service, 

Southeastern Forest Experiment Station, Forestry 

Sciences Laboratory, Athens, Georgia. 

METHODS 

The study area is in the Upper Piedmont of 

Georgia on the Dawson Forest, which is managed 

by the Georgia Forestry Commission. Detailed 

site and stand characteristics were presented 

earlier. Table 1 presents average initial stand 

composition by general species group and size 

class. One-acre treatment plots were harvested 

using a typical whole-tree system that included 

a small feller-buncher and grapple-skidders. 

Harvesting removed all material down to 4-inch 

or 1-inch diameter limits in both January and 

June of 1980. Each combination of season and 

intensity was replicated three times in a 

completely randomized design. Detailed observations and measurements were confined to the 

interior 0.5 acre of each 1-acre plot. 

Coppice regrowth was characterized from a 

100-percent inventory of sprout clumps that were 

at least 4.5 feet tall after the fifth growing 

season (virtually all clumps). Sprout clump 

coverage per acre was calculated from estimates 

of the average crown diameter at the height of 

maximum crown spread. This value is essentially 

an aggregation of clump crown projections by 

species. 
Table 1,--Initial stand basal area by species 

group and size class 

- 

1 / 

-- Size class- 

-- Species group Sapling Pulpwood sawtimber ----- ft2/acre - - - - - 

Pine 7 15 3 

Red oaks 5 8 ! 2 

White-post-ches tnut oak 5 6 8 

Other hard hardwoods 4 '- 3 2 

Soft hardwood 1 1 1 

Shrub 1 - - 

:iiscellaneous 6 3 I 

All Species 2 9 35 2 7 

- 1 / 

Saplings 0.5-4.5 inches d. b . h. , pulpwood 

4.6-9.5 inches, sawtimber 9.6 inches minimum d.b.h, 

Since the original design focused on stand development of species mixtures, rather than individual trees or species, all species did not occur 

on all plots. However, 11 species were represented on all plots in the coppice stands as well 

as the initial stands. They were (in order of 

initial stand basal area) scarlet oak, post oak, 

black oak, chestnut oak, southern red oak, 

hickory, blackjack oak, sourwood, white oak, 

dogwood, and blackgum. These species occurred in 

varying proportions from plot-to-plot. To reduce 

species response to an equivalent basis, coppicing 

was expressed as the following ratio : 

CRi= CVi/BAi, where 

CR = coppicing ratio, 

CV = square feet per acre of fifth-year 

coppice crown coverage, 

BA = square feet per acre of basal area in 

the initial stand, 

i = ith species 

The calculated coppicing ratios were subjected to 

analysis of variance. To compare relative 

sprouting potential among species, an index--the 

quotient of two coppicing ratios--was calculated 

for species pairs. 

RESULTS A%D DISCUSSION 

Coppice coverage per square foot of initial basal 

area was significantly affected by intensity of harvesting and by species (Table 2). Significantly 

more coppice coverage might have resulted from the 

dormant season harvesting, but seasonal effects were 

conforrnded by heavy pine natural regeneration following dormant-season harvesting only (McPfinn 1985a). 

Differences by season were nonsignificant as were 

all. possible interactions. The coppicing ratio was 

38hsquare feet of crown coverage per square foot 

of initial basal area for I-inch limit harvesting 

versus only 158 for 4-inch limit plots. The difference is attributed to competition from the residual 

stems in the 4-inch-limit treatment, rather than to 

a larger number of potential sprouting stumps in 

the 1-inch-limit harvesting. Early in the study, 

there was evidence that the residual stands offered 

substantial competition to both hardwood coppice and 

pine regeneration (EfcMinn 1985b). A very high proportion of the smaller stumps were completely destroyed in the 1-inch-limit harvesting operation, 

Table 2 .--;lnalysis of variance results for coppice 

coverage per unit of initial stand basal area 

---- 

Source d f F Prob > F 

Season 1 1.90 0.1716 

Intensity 1 21.77 0.0001 

Species 10 3.78 0.0003 

Season x intensity 1 1.04 0.3100 

Season x species 10 C.57 C. 8332 

Intensity x species 10 1.03 0.4217 

Sea. x int. x 2ec. 10 0.95 0.4891 

Coppicing ratio by species ranged from 558 down 

to 74 (Table 3). Percentage distributions in 

sapling, pulpwood, and sawtimber classes give no 

indication that the species differences are due to 

size. In some species, however, sprouting potential appears to vary with size or age as reflected 

by size (Johnson 1975, Johnson 1977). The two 

most prolific sprouters, dogwood and sourwood, are 

inherently small species, as is the least prolific, blackjack oak, There is no apparent trend in 

any of the size classes as the coppicing ratio 

changes among the other species. 

Table 3.--Coppicing ratio and percentage distribution 

of initial stand basal area by general size class 

for eleven species in the Upper Piedmont 

Coppicing - Size Class 

-- ratio Sapling Pulpwood Sawtimber 

Dogwood 

Sourwood 

White oak 

Chestnut oak 

Blackgum 

Southern red oak 

Scarlet oak 

Black oak 

Hickory 

Post ozk 

P 

Blackjack oak 

---- percent - - - - - 

Table 4 indicates a substantial potential for 

species predominance to change in coppice stands 

compared to initial stands, even among closely 

ranked sprouters occurring in this study. For 

example, among the five most prolific sprouters, 

dogwood produced almost 60 percent more coppice 

coverage than white oak per square foot of initial 

basal area and white oak produced 22. percent more 

than blackgum. Among the five species occupying 

the middle range, chestnut oak produced 32 percent 

more coppice than southern red oak and southern 

red oak produced 43 percent more than black oak. 

Among the five Least prolific sprouters, scarlet 

oak produced 38 percent more than hickory and hickory produced over twice as much as blackjack oak. 

Very obvious potentials for species shifts are 

apparent when the coppicing of our five most prolific and least prolific species are compared 

(Table 5), In the most extreme case, dogwood produced over seven and a half times as much sprout 

coverage as blackjack oak per square foot of initial basal area, and sourwood produced almost 

seven times as much as blackjack oak. However, 
even though these two species resprout vigorously, 

they will ultimately become understory or midstory 

components. Among the species that will ultimately form the dominant overstory, white oak production was over three and a half times as much as 

post oak and almost five times as much as blackjack oak. Similarly, chestnut oak was over three 

tixnes as prolific as post oak and over four times 

as prolific as blackjack oak. 

Table 4.--Quotients of coppicing ratios between 

species pairs for species exhibiting high to low 

sprouting tendencies (based on coppicing ratios 

for all study treatments) 

(a) High range 

DOWO : 1 .89 .63 .57 .52 

SOW0 : 1.12 1 .7 1 .64 .59 

WHOA : 1.58 2.40 1 .90 -82 

CHO A : 1.75 1.56 1.11 1 .92 

BLGU : 1.92 1.71 1.22 1.09 1 

(b) Middle range 

Species : CHOA BLGU SROA SCOA BLOA 

CHOA : 1 .9 2 .76 .67 .53 

BLGU : 1.09 1 .83 .74 .58 

SROA : 1.32 1.21 1 .89 .70 

SCOA : 1.49 1.36 1.13 1 .79 

BLOA : 1.88 1.72 1.43 1.27 1 

(c) Low range 

Species : SCOA BLOA HICK POOA BJOA 

S COA : 1 .79 .72 .46 .35 

BLOA : 1.27 1 .92 .58 .44 

HICK : 1.38 1.09 1 .63 .48 

POOA : 2.18 1.72 1.58 1 .76 

BJOA : 2.89 2.28 2.09 1.32 1 

ljBJOA = blackjack oak, BLGU = blackgum, BLOA = 

black oak, CHOA = chestnut oak, DOWO = dogwood, 

HICK = hickory, POOA = post oak, SCOA = scarlet 

oak, SOW0 = sourwood, SROA = southern red oak, 

WHOA = white oak, 

Table 5 .--Quotients of coppicing ratios between 

species pairs for species exhibiting high and low 

sprouting tendencies 

Species : DOWO SOW0 WHOA CHOA BLGU 

S COA : 2.61 2.32 1.65 1.49 1.36 

BLOA : 3.30 2.94 2.09 1.88 1.72 

HICK : 3.60 3.21 2.28 2.05 1.88 

POOA : 5.69 5.07 3.61 3.24 2.97 

BJOA : 7.54 6.72 4.78 4.30 3.93 

The foregoing figures on relative coppicing 

should be interpreted as tendencies towards species shifts , rather than indices of ultimate dominance. The predominance of a species in the 

coppice regrowth is a product of the interaction 

between coppicing potential and predominance in 

the initial stand. In addition, sprout mortality 

may be a factor in the ultimate species dominance 

within a stand (Johnson 1977). Table 6 presents 

the overall shifts in ranking for the species 

occurring in this study. As a result of the differential coppicing, only 4 of the 11 species 

remained within one position of their original 

ranking. As might be expected, dogwood and sourwood underwent the most drastic shifts upward (6 

and 5 positions, respectively). Even though these 

species will ultimately occupy the midstory, their 

predominance at the coppice stage probably influences the ultimate predominance of different overstory species via species variation in competitive 

capacity at the coppice 'stage, Hickory, post oak, 

and blackjack oak shifted downwards three, five , and three positions, respectively. Since these are 

the least desirable of the overstory species, 

complete removal of all woody biomass should 

result in some upgrading of the subsequent stands. 

Table 6,--Coppicing ratio, percent of initial stand 

basal area, percent of coppice coverage, initial 

stand rank, and coppice stand rank by species 

- -- 

Coppicing Percent of Rank 

Species ratio Stand Coppice Stand Coppice 

Dogwood 

Sourwood 

White oak 

Chestnut oak 

Blac kgum 

Southern red 

oak 

Scarlet oak 

Black oak 

Hickory 

Post oak 

Blackjack oak 

ACKNOWLEDGEEIENT 

The author expresses his appreciation to the 

Division of Research, Georgia Forestry Commission, 

for the support and cooperation that made this 

research possible. 

LITERATURE CITED 

Butts, Paul M.; Preston, Druid N. 1979. Whole tree 

chipping: a forest management tool. Ga. For. Res. 

Pap. 4, Macon, GA: Georgia Forestry Commission; 8 pp. 

Johnson, Paul S. 1975. Growth and structural 

development of red oak sprout clumps. Forest 

Science 21:413-418. 

Johnson, Paul S. 1977. Predicting oak stump 

sprouting and sprout development in the Missouri 

Ozarks, Res. Pap. NC-149. St. Paul, MN: U.S. 

Department of Agriculture, Forest Service, 

North Central Forest Experiment Station; 11 pp. 

McMinn, James W. 1985a. Coppice regeneration of 

upland hardwoods from intensive whole-tree 

harvesting. In: Shoulders, Eugene, ed . Proceedings, 3rd biennial southern silvicultural 

research conference. 1984 November 7-8 ; Atlanta, 

GA. Gen. Tech. Rep. SO-54. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 159-162. 

McMinn, James W. 1985b. Whole-tree harvesting affects 

pine regeneration and hardwood competition. 

Southern Journal of Applied Forestry 9(2):81-84. 
Even-Aged Regeneration Alternatives for Law Quality Mixed 

Hardwood Forests in the Virginia Piedmont1 

Keith P. Newcomer, Shepard M. Zedaker, 

David Wm. Smith, and Richard E. ~reh' 

.-- The effects of site quality, harvest season, and 

enerati s on natural hardwood and planted 

loblolly pine ( L.) growth and density are 

evaluated three years after clear felling. Low-quality stems 

and poor species composition characterized six similar pairs 

of plots xandomly selected for dormant or growing season 

harvests. The four regeneration treatments were (1) clear 

felling and whole-tree harvest only; (2) clear felling and 

whole-tree harvest with planted loblolly pine seedlings; (3) 

clear felling, herbicide treatment of all hardwood stmps at 

time of felling, and pine planting; (4) clear felling, stmp 

treatment at time of felling, pine planting, and an herbicide 

pine release after one growing season. Natural regeneration 

growth was significantly greater with a dormant season harvest, while planted pine growth was significantly greater 

with a growing season harvest. The reduced amount of hardwood 

regeneration resulting from the herbicide treatments was accompanied by an increase in pine growth. 

A significant amount of the Virginia forest resource is in the Piedmont Physiographic Province 

which contains 2.5 million hectares of private and 

industrial commercial forest land (Brown 1986). 

Over one million hectares, 72% of Virginia 

Piedmont forests, are composed of upland hardwoods 

and oak-pine forest types (Brown 1985,1986). The 

potential for wood production of these forests is 

severely limited by an abundance of low quality 

stems and undesirable species. The 1977 U. S. D. A. 

forest inventory in the Virginia Piedmont found 75% 

of these forests are understocked with 20% of the 

stocking in rotten and poorly formed trees (Knight 

and McClure 19783. Poor stand conditions are 

largely a result of natural succession from 

farmland following abusive agricultural practices, 

continuous detrimental high-grading, and wildfire 

(Smith and Limartz 1980). A recent finding that 

planted pines represent only 4% of the total 

biomass in Piedmont forests suggests that a lack 

of pine regeneration is also a problem limiting 

forest productivity (Bechtofd and Phillips 1985). 

'paper presented at Southern Silvicultural 

Conference Research Conference, Atlanta, 

Georgia, November 4-5, 1986. 

2~raduate Research Assistant, Assistant 

Professor, Professor, and Research Associate, 

respectively, Department of Forestry, VPI &SU, 

Blacksburg, VA 24061. 

The large area represented by upland hardwood mid 

oak-pine forest types, the inferior quality of 

these stands, and the very small portion of 

Piedmont forests in pine plantations points to the 

need for developing even-aged silvicultural guidelines that can convert low quality hardwood stands 

into productive hardwood, mixed hardwood-pine, or 

pine forests. Land ownership patterns in the 

Piedmont are also influential in the design of appropriate silvicultural systems. Because 81% of 

Virginia Piedmont forests are composed of small, 

privately owned woodlands, regeneration alternatives must be developed that are applicable over a 

wide range of landowner objectives, tract sizes, 

and management intensities (Bechtold and Phillips 

1985 1. 

The objective of this ongoing study is to formulate even-aged regeneration alternatives appropriate for a variety of woodland owners in the 

Virginia Piedmont. In this paper, the effects of 

site quality, season of harvest, and 4 even-aged 

regeneration treatments on natural hardwood and 

planted loblolly pine growth, and density are 

evaluated 3 years following clear felling and 

whole-tree removal in Virginia Piedmont mixed oak 

stands. 

Studv Area 

The study site is located in the Virginia 

Piedmont at Virginia Polytechnic Institute and 
State University" Reynolds Homestead Research 

Center, nser Critz, VA. The soils are leached, 

eroded Ultisols developed mainly from granitic and 

metamorphic bedrock. Slopes range from 2-20% with 

6-8% being mast common. Annual precipitation averages 125 centimeters and is well distributed 

through the year. The frost free season averages 

196 days ( Crockett 1973). 

The plots were located in 50-80 year-old second 

growth oak-hickory forests on site qualities ranging from site index 15-23 meters (base age 50) for 

L. ) (Carmean 197 1, 

Pre-harvest stands contained an 

average of 24.3 square meters of basal area per 

hectare 011 the poorer sites, and 27.0 square meters 

of basal area per hectare on the better sites. Oak 

species comprised about 59% of the basal area on 

the poorer sites, and 34% on the better sites. The 

d d on poorer sites included 

c pas L. ), scarlet oak 

( nchh. ) , red maple (b 

rubrum L.), and sourwood (Oxvdendrum arboreum (L.) 

DC) , with scattered Virginia pine (Pinus yirniniana 

Mill. ) , and white pine (Pinus strobus L. ). White 

oak, yellow-poplar (Liriodendron tuli~ifera L.), 

red maple, sourwood, and northern red oak (Ouercus 

xubra L. ). dominated the better sites with smaller 

amounts of scarlet oak, and American beech (Fanus 

grandifolia Ehrh. ). 

Studv Design 

The study contains 3 blocks, and is a split-split 

plot desigl. Each block contains 2 site classes, 

good and poor, representing the main plot. Site 

indices range from 15-19 meters for white oak (base 

age 50) on poor sites, and 20-23 meters for white 

oak (base age 50) on good sites (Carmean 1971, 

Doolittle 1975). 

Each half of the main plots was randomly assigned 

a dormant or growing season harvest, representing 

the first split, The dormant season harvest kas 

completed between 17 February and 29 April, 1983. 

The growing season harvest was accomplished between 

6 June and 11 August, 1983. 

The determination of treatment effects was accomplished by subdividing each site class-harvest 

season unit into four 30 meter by 30 meter plots 

representing the second split. Each split-split 

plot was rcindomly assigned one of the following 

four treatments: 

Ti) Clear felling and whole-tree 

harvest only. 

TZ) Clear felling and whole-tree 

harvest, and planted loblolly 

pine seedlings. 

T3) Slear felling and whole-tree 

harvest, herbicide treatment 

of all hardwood stumps, and 

planted loblolly pine 

seedlings. 

T4) Clear felling and whole-tree 

har-rest, herbicide treatment 

of all hardwood stumps, 

planted loblolly pine 

seedlings, md a release 

treatment of pine seedlings. 

Each regeneration treatment employed a clear 

felling whole-tree harvest. All stems greater than 

2.5 centimeters dbh were felled within 15 centimeters of ground level. 

Treatments 2, 3, and 4 included planting genetically improved 1-0 loblolly pine seedlings from a 

Virginia Piedmont source in March 1984. Seedlings 

were hand planted on a 2 meter by 2 meter grid resulting in a density of 2500 seedlings per hectare, 

The cut-stump herbicide treatment used in Treatments 3 and 4 consisted of a thin stream of undiluted herbicide applied to the cambial region of 

the stump immediately following cutting. All 

hardwood stumps were treated at an average rate of 

0.27 liters per square meter of basal area. 

Triclopyr (3,5,6-trichloropyridinyloxyacetic acid 

as Garlon-4@61.6% EC), glyphosate (Nphosphonomethyl glycine as Roundup@ 41.0% SL), 

dicamba (3,6-dichloro-o-anisic acid as Banvel CSm 

10.6% SL), and picloram (4-amino-3,5,6- 

trichloropicolinic acid as Tordon-101@ 5.4% SL) 

were used for the cut-stump treatment (Zedaker et 

al. in press). 

Treatment 4 plots received a pine release in 

March 1985. Plots were randomly split so that each 

half received a basal bark spray, or a soil applied 

herbicide release treatment. 

The basal bark spray release method consisted of 

4% triclopyr (ester) (as Garlon-4@ 661.6% EC) diluted with diesel fuel and applied with a backpack 

sprayer. The mixture was applied to the bottom 

15-20 centimeters of treated stems until runoff. 

All stems within 1 meter of loblolly pine seedlings 

were treated. An average of 3.4 liters of triclopyr 

and 82 liters of diesel fuel were used to release 

1300 loblolly pines per hectare. An average of 11.6 

man-hours was required to treat 1 hectare. 

The soil active herbicide was applfed as 50% 

hexazinone (3-cyclohexyl-6-(dimethylamino) 

-1-methyl 1-1,3,5-triazine-2,4(1H,M)dione as 

Velpar L@ 25% SL) in water with a spotgun. The 

mixture was applied in 6 evenly spaced 2.5 milliliter spots arranged in a 1 meter radius circle 

around each loblolly pine seedling. An average of 

9.7 liters of hexazinone was used to release 1300 

loblolly pines per hectare. The time required to 

treat 1 hectare averaged 6.6 man-hours. 

Natural regeneration was sampled at the end of 

the 1985 growing season in all 4 treatments. Nine 

randomly located 2 meters x 2 meters plots were 

sampled in each 30 meters x 30 meters treatment 

plot. All natural regeneration taller than 25 

centimeters was tallied for a) species, b) total 

height, and c) two crown diameters taken at right 

angles to each other from terminal bud to terminal 

bud. 
Loblolly pine growth was also measured at the 

end of the 1985 growing season. All surviving RESULTS AND DISCUSSION 

loblolly pines were measured for a) total height, 

and b) groundline diameter. 

Analvsis The good site class averaged 10,978 cubic meters 

of natural hardwood crow volume per hectare, while 

the poor site class averaged 10,944 cubic meters The effects of site quality, season of harvest, per hectare. The density of free-to-grow crop and the 4 regeneration treatments on natural re- species was also similar between site classes, generation total crown volume (crown 1,957 stems per hectare and 1,806 stems per hectare volume=heightx3. 14x( crown radius) * ) were examined on good and poor sites, respectivs.ly. However, using split-split plot analysis of variance free-to-grow, non-crop species were nearly twice (ANOVA). An alpha level of 0.05 was used for all as numerous on the good site class, 3,068 stems per significance tests. hectare, than on the poor site class, 1,759 stems 

ANOVA was performed on the density of free-togrow natural regeneration crop and non-crop species. If height was greater than 1.25 times the 

mean height of all regeneration in a treatment 

plot, an individual was considered free-to-grow. 

Density was defined as the number of free-to-grow 

trees per hectare. Crop species included pignut 

hickory (Carva plabra Mill.), mockernut hickory 

(Car~a tomentosa Poir. Nutt.), yellow-poplar, white 

oak, scarlet oak, chestnut oak, and northern red 

oak. Free-to-grow non-crop species included 

tree-of-heaven (Ailanthus altissima Mill.), red 

maple, flowering dogwood (Cornus florida L.), 

blackgum (Nvssa svlvatica Marsh.), sourwood, 

sassafras (Sassafras albidum Nutt.), black locust 

(Robinia pseudoacacia L.), black cherry (Prunus 

serotina Ehrh. ) , and American beech. 

The effects of site quality, season of harvest, 

and 3 regeneration treatments on planted loblolly 

pine total crown volume was analyzed using ANOVA 

and ~uncan's MRT. Crown volume was estimated from 

groundline diameter using a linear equation developed by Zedaker and others ( in prep. ). ANOVA is 

also performed on the density of free-to-grow 

loblolly pines. If height was greater than the 

mean height of all natural regeneration in the 

treatment plot, a planted loblolly pine was considered free-to-grow. 

per hectare. 

Total hardwood crown volume was significantly 

greater with a dormant season harvest, 14,442 cubic 

meters per hectare, than with 8 growing season 

harvest, 7,780 cubic meters per hectare. The 

larger size of hardwood regeneraton after a dormant 

season harvest was probably a result of the greater 

carbohydrate reserves stored in dormant tr_ee roots 

(Roth and Hysting 1943) and the better growing 

conditions available to all regeneration when the 

overstory was removed before the spring growing 

season. The density of free-to-grow crop species 

was greater with a dormant season harvest, 2,084 

stems per hectare, than with a growing season harvest, 1,678 stems per hectare. The density of 

free-to-grow non-crop species was also greater with 

a dormant season harvest, 2,709 stems per hectare, 

than with a growing season harvest, 2,118 stems per 

hectare. 

Treatments 1 and 2 contained similar amounts of 

hardwood crown volume, but total hardwood crown 

volume was significantly reduced by the herbicide 

cut-stump treatment in Treatment 3, and further 

reduced by the herbicide cut-stump treatment and 

pine release in Treatment 4 (Table 1). The density 

of free-to-grow crop and non-crop species was significantly affected by the regeneration treatments 

Table 1: Natural regeneration total crown volume by regeneration treatment, harvest season, and site 

class after 3 growing seasons. 

Regenerat i on - Treatment 

SITE CLASS 

POOR GOOD 

Season of Harvest 

Dormant Growi ng Dormant Growi ng 

Crown volume 

(m3/ha 

Total 

Crown 

Vo l ume 

Clearcut,Stump 

Treatment, 4,579fg 1,1879 

Pine, Release 

a/ - Across all seasons of harvest and site-classes, treatment means followed by the same letter are not significantly different at alpha=0.05 (~uncan's Multiple Range Test). 

- Overall regeneration treatment means followed by the same letter are not significantly 

!ffferent at alpha = 0.05 (~uncan's Multiple Range Test). 
Table 2: Density of free-to-grow hardwood crop species by regeneration treatment, harvest season, and 

site class after 3 growing seasons. 

SITE CLASS 

POOR GOOD 

Regener at i on Season of Harvest 

Treatment 

Dormant Growi ng Dormant Grow i ng 

Total 

Dens i ty 

Dens i ty 

(no/ha 1 

a / 

Clearcut 1,481s 1,296a 2,973a 1,297a 

Clearcut,P ine 1,481a 741a 1,018a 1,760a 1,2508 

Clearcut ,Stump 

Treatment,Pine 2,731a 2,037a 

Clearcut ,Stump 

Treatment, 2,407a 2,871a 

Pine, Release 

- Across all seasons of harvest and site classes, treatment means followed by the same letter 

:!e not significantly different at alpha=0.05 (Duncan's Multiple Range Test). b/ - Overall regeneration treatment means followed by the same letter are not significantly 

different at alpha = 0.05 (~uncan's Multiple Range Test). 

Table 3: Density of free-to-grow non-crop species by regeneration treatment, harvest season, and site 

class after 3 growing seasons. 

SITE CLASS 

POOR GOOD 

Regeneration Season of Harvest 

Treatment 

Dormant Growing Dormant Growi ng 

Total 

Dens i ty 

Dens i ty 

(no/ha 1 

Clearcut 

Clearcut ,Stump 

Treatment, 1389de 741e 

Pine, Release 

- Across all seasons of harvest and site classes, treatment means followed by the same letter 

:!e not significantly different at alpha=0.05 (Duncan's Multiple Range Test). - Overall regeneration treatment means followed by the same letter are not significantly 

:ifrerent at alpha = 0.05 (~uncan's Multiple Range Test). 

(Tables 2 arid 3). The relatively high density of The density of free-to-grow crop and non-crop free-to-grow natural regeneration in Treatment 3 species was much less influenced by harvest season and 4 plots, despite the herbicide treatments, at- and regeneration treatment than natural regener- tested to the abundance of natural regeneration ation size. Hardwood distribution was probably typical in these clearcuts, particularly on the more influenced by pre-harvest stand composition good site class. and seed dispersion from adjacent stands. Because 

Examination of total hardwood crown volume 

(Table 1) revealed that for all site classregeneration treatment combinations, hardwood 

growth was greater with a dormant season harvest. 

On both site cl~sses, greatest growth occurred when 

the harvest was performed during the dormant season 

and no herbicide treatments were applied. The 

herbicide cut-stump treatment, and the herbicide 

cut-stump treatmert plus pine release resulted in 

less growth of na-ural hardwood regeneration when 

applied in treatment plots which received a growing 

season harvest. 

non-crop species were generally more densely distributed than crop species, intermediate stand 

treatments may be needed to favor crop trees. 

Nearly twice as much total loblolly pine crow 

volume was found on the poor site class, 484.4 capbic meters per hectare, than on the good site 

class, 263.3 cubic meters per hectare. The inverse 

relationship between total loblolly pine volme 

index and site index at age 2 appears to be par- 
Table 4: Planted pine regeneration total crown volume by regeneration treatment, harvest season, and 

site class after 2 growing seasons. 

SITE CLASS 

POOR GOOD Tota 1 

Regeneration Season of Harvest B8Sa 

Treatment Area 

Dormant Grow i ng Dormant Crowi ng 

Crown volume 

(m3/ha) 

a/ 

Clearcut,Pine 136. lef 578.4b 46.8f 244.2de 

Clearcut,Stump 

Treatment, 382.8cd 964.3a 

Pine, Release 

a/ - Across all seasons of harvest and site ctasses, treatment means fot lowed by the same letter 

are not significantly different at alpha=0.05 (~unean's Multiple Range Test). 

- Overall regeneration treatment means followed by the same letter are not significantly 

:iffwent at alpha = 0.05 (~uncan's Multiple Range Test). 

tially a result of the greater density of competing natural regeneration on the good site class. 

The more uniform shading from the more densely 

distributed natural regeneration on the good site 

class resulted in smaller individual loblolly pine 

crown volume, 0.26 cubic meters, than on the poor 

site class, 0.48 cubic meters. However, similar 

numbers of free-to-grow pines occupied the good and 

poor site classes, 862 per hectare and 928 per 

hectare, respectively. 

Treatment plots harvested during the growing 

season contained significantly more loblolly pine 

crown volume, 564.9 cubic meters per hectare, than 

those harvested during the dormant season, 182.9 

cubic meters per hectare. The greater pine growth 

was probably a result of the significantly smaller 

amount of natural regeneration crown volume found 

in growing season harvest plots. The significantly 

larger number of free-to-grow planted pines following a growing season harvest, 1486 stems per 

hectare, compared to only 306 trees per hectare 

with a dormant season harvest, suggested that 

harvest seassn effects on loblolly pine growth at 

age 2 will persist as the stand develops. 

Greater growth and more free-to-grow loblolly 

pines also resulted because the herbicide treatments reduced competition from natural hardwood 

regeneration. Significantly more total crown volume (Table 4) and free-to-grow plnes(Tab1e 5) developed with the use of the herbicide cut-stump 

treatment and pine release, than with the herbicide 

cut-stump treatment only or no control 

A comparison of Loblally pine regeneration in all 

3 regeneration treatments revealed that, on both 

site classes, total crown volume (Tabbe 4), and 

Table 5: Density of free-to-grow loblolly pine by regeneration treatment, harvest season, aod site class 

after 2 growing seasons. 

SITE CLASS 

POOR 

Regeneration Season of Harvest 

Treatment 

Dormant Grow i ng Dormant Growing 

Dens i ty 

(no/ha 

Tota I 

Dens i ty 

Clearcut,Stump 

Treatment, 748cd 7755ab 

Pine, Release 

a/ - Across all seasons of harvest and site classes, treatment means followed by the same letter are not significantly different at alpha=0.05 (~uncan's Multiple Range Test). 

b/ - Overall regeneration treatment means fotlowed by the same letter are not significantly 

different at alpha = 0.05 (~uncan's Multiple Range Test), 
density of free-to-grow trees (Table 5) was significantly greater with a growing season harvest. 

On both site classes a growing season harvest with 

no herbicide treatments, resulted in more crown 

volume and free-to-grow loblolly pines than a dormant season harvest with the herbicide cut-stump 

treatment plus pine release used in Treatment 4. 

Conversion of mixed hardwood stands to planted 

loblolly pine was much more difficult if the 

preceeding stand was harvested during the dormant 

season. 

Natural hardwood regeneration crown volume was 

similar on both site classes but density was 

greater on the good site class than on the poor site 

class. Planted loblolly pine growth, expressed as 

pine crown volume, was almost 2 times greater on 

the poor site class, due partially to the less 

densely distributed hardwood competition. On the 

good site class the density of non-crop species far 

exceeded crop species, indicating that a cleaning 

or crop-tree release may be warranted. These results suggest that site quality is an important 

consideration when choosing a regeneration system. 

Harvest season also affected planted loblolly 

pine and natural hardwood regeneration differently. 

Natural hardwood regeneration was favored with a 

dormant season harvest while planted pines exhibited greater growth following a growing season 

harvest. These findings indicate that the timing 

of a clear felling regeneration treatment can be 

used as an important basic silvicultural tool. 

The addition of planted pines in Treatment 2 did 

not significantly reduce natural regeneration 

growth from that found on Treatment 1 plots. The 

cut-stump herbicide treatment effectively reduced 

natural hardwood regeneration growth as exhibited 

by reduced total crown volume. Addition of a pine 

release resulted in even greater natural regeneration control. The reduction in hardwood growth 

with the herbicide treatments was accompanied by 

an increase in planted pine growth. The effectiveness of the herbicide treatments was greatly enhanced by a growing season harvest. 

CONCLUSIONS 

When a clear felling and whole-tree harvest only 

was used in upland mixed hardwood stands it appeared that stocking and species composition did 

not change drastically from the pre-harvest stand. 

A dormant season harvest can be used to accelerate 

the growth and establishment of natural regeneration. Species composition can be influenced at the 

time of clear felling if undesired hardwood stumps 

are treated with an herbicide. 

Planted loblolly pines were favored over natural 

regeneration if a growing season harvest was used. 

Herbicide treatments can also be used to favor 

planted pine regeneration. The larger pine crown 

volume on the poor site class at age 2 suggested 

that planted pine regeneration was more easily established on lower quality sites. 

The findings of this study encouraged the possibility of regenerating mixed natural hardwoodplanted pine. A growing season harvest can be used 

to favor the establishment of planted pine regeneration over natural regeneration. nree years after clear felling, it appeared that free-to-grow 

pines will become a component of the future stand, 

supplementing the stocking of natural regeneration. 

This research was supported by the management of 

Piedmont Hardwoods Research Unit, USDA-Forest Service, Southeastern Forest Experiment Station, 

Clemson, S.C.; and the Reynolds Homestead Research 

Center, Critz, Va.; and McIntire Stennis Fund. 

LITERATURE CITED 

Bechtold, William 8.; Phillips, Douglas R. The 

hardwood resodrce on nonindustrial private 

forest land in the Southeast Piedmont. Res. 

Pap. SE-236. Asheville, NC: U.S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Stat ion; 1985.19~~. 

Brown, Mark J. Forest statistics for the Southern 

Piedmont of Virginia,1986. Resour. Bull. 

SE-81. Asheville, NC: U. S. Department of 

Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1985. 52pp. 

Brown, Mark J. 1986. Forest statistics for the 

Northern Piedmont of Virginia, 1986. Resour. 

Bull. SE-84. Asheville, NC: U. S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1985. 52pp. 

Brown, Mark 3. Forest statistics for Virginia, 

2986. Resour, Bull. SE-84. Asheville, NC: 

U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station; 1986. 52pp. 

Carmean, W.H. Site index curves for black, white, 

scarlet, and chestnut oaks in the Central 

States. Res. Pap. NC-62. U.S. Department of 

Agriculture, Forest Service, North Central 

Forest Experiment Station; 197 1.8pp.' 

Doolitt le, W. T. Site index comparisons for several 

forest species in the southern Appalachians. 

In: Soil Science Society of America Procedings, vol. 22, 1975. 455-458. 

Knight, H. A. ; McLure 3. P. virginiat s timber, 1977. 

Resour. Bull. SE-44, Asheville, N. C. : U. S. 

Department of Agriculture, Forest Service, 

Southeast Forest Experiment Station; 

1978.53~~. 

Smith, David Wm.; Linnartz, Norwin E. The southern 

hardwood region. In: Barrett, John, ed. Regional silviculture of the U. S. 2d ed. New 

York: 1980: 145-230. 
Zedaker , Shepard M. ; Smith, David Wm. ; Lewis, James 

B, Impact of season of harvest and site 

quality on cut-stump treatment of Piedmont 

hardwoods. Southern Journal of Applied 

Forestry. (in press). 

Zedaker, Shepard M.; Bacon, Catherine G.; Burch, 

Patrick. Basal area, crown volume, and 

biomass relationships for Southeastern 

hardwoods. ( in prep. ). 
EVALUATION OF SMLING METHODS TO ESTIMATE THE LEVEL OF 

COXPETING HARDWPOD VEGETATION IN YOUNG 

2 D. R. WEISE AND G. R. GLOVER 

ABSTRACT.--Performance of 42 sampling rules was tested 

by computer simulation using 24 artificial hardwoqd 

rootstock populations of varying density and spatial 

pattern. Sampling rules were evaluated using relative 

bias, relative precision, variance, and consistency as 

criteria. All fixed area and polyareal estimates were 

unbiased, but ~atcheler's triple distance estimates were 

affected by sampling intensity and biased by spatial 

pattern. Polyareal methods had greater relatiie 

precisi'on, lower variance, and greater consistency than 

fixed area methods. IIorizontal line sampling (crown 

di'ameter factor = 100 ft] is recommended as the "best" 

method for quantifying competing hardwood vegetation. 

Ffeld testing to determine practicality is necessary. 

INTRODUCTION 

Planted 1ob.lolly pine (Pinus taeda L) seedlings 

grow better in the absence of competing 

vegetation, as does any agronomic crop. It is 

often desirable to determine the amount or level 

of hardwood vegetation in a young plantation in 

order to evaluate the effectiveness of a site 

preparation treatment or the need for a pine 

release operation. Few objective field survey 

methods exist that are specifically designed to 

measure hardwood vegetation growing in young 

lohlolly pine plantations in the Southeastern 

United States. Zutter et al. (.I9851 identified 

some of the desirable attributes that such a 

method should exhibit. These include 

objectivity, simplicity, campatibility with other 

surveys, and a wide range of applicability. Such 

a survey method could supply information for 

evaluation of site preparation effectibeness, 

determinatfon of need for pine release, and ihpat 

into growth and yield models that simulate the 

effects of hardwood competition on pine yield. 

The need for an objective, accurate method is 

becoming critical as costs of ~arfoas cultural 

treatments associated with establiding and 

maintaining young pine plantations increase. 

This study was designed to identify one or more 

operational sampling rules that may be used to 

A~aper presented at the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, GA, 

November 4-6, 1986. 

 o or ester, Southeastern Forest Experiment Station, 

Southern Forest Fire Laboratory, Dry Branch, GA 

31020 (formerly Graduate Research Assistant, School 

Forestry, Auburn University) and Assistant Professor, 

School of Forestry, Auburn University, Alabama 

Agricaltural Experihlent Station, Auburn University, 

AL 36849-4201. 

estimate the level of competing hardwood 

vegetation in young loblolly pine plantations 

through computer simulation. 

METHODS 

Several sampling studies have been conducted 

using computer simulation (i.e. Palley and 

O'Regan 1961, Kaltenberg 1978). In most cases, 

the studies have simulated mature forests. 

Kaltenherg examined the effects of spatial 

pattern on estimates of stocking and density in 

seedling stands. No sampling studies of 

compet ing hardwood vegetation in pine plantat ions 

were found ih the literature. 

A stand simulator was developed from data 

collected in 19 loblolly pine plantations and was 

,used to produce artificial hardwood rootstock 

populations skmilar to those observed in young 

loblolly pine plantations in the Piedmont and 

upper Coastal Plain of Alabama (Weise and Glover, 

in prepayation). Twenty-four 16-acre stands with 

nominal population densities of 500, 1500, or 

25Ci0 ~ootstocks per acre (low, medium, and high 

densfty) and values of Pielou's Nonrandomness 

Index (Pielou 1937) of Q.6, 1.0, 1.6, and 2.2 

Cunif om, random, lightly clumped, and heavily 

clumpedt aged 3 or 6 years since planting were 

used 2n this stady. Total rootstock height was 

determined by a two parameter left and right 

truncated Weibull function and crown area was 

determfned as a function of total height. 

S'ix basic randm sampling schemes were 

examined: fixed area plots, horizontal points, 

horizontal line, vertical point, vertical line, 

and Batcheler 's triple distance method (Marren 

and Batcheler 19792. All combinations of plot 

sizes of 0.002, 0.004, and 0.01 acre and of 

circular, square, and ~ectangular (4 x 1) plot 

shapes were tested using a 1 percent sampling 
percentage (9 sampling rules). Horizontal point, 

horizontal line, vertical point, and vertical 

line schemes, all variable probability methods, 

were tested at sampling intensities of 1, 2.5, 

and 5 points per acre (Grosenbaugh 1958, Wusch et 

al. 1982). All line samples were 50 feet long. 

Rootstocks were selected in proportion to crown 

area, crown diameter, total height and total 

height squared by horizontal point, horizontal 

line, vertical point, and vertical line sampling 

rules, respectively. Crown factors (CF) of 100 

and 200 square feet (or feet) were selected for 

the horizontal methods (12 sampling rules). 

Vertical angles of 30O, 45O, and 60' were 

selected for the vertical methods (18 rules). 

Batcheler's method estimates density using 

3 distance measures: distance between a sample 

point and the nearest rootstock, between the 1st 

rootstock and the rootstock nearest it, and from 

the 2nd rootstock to the rootstock nearest it 

Cexcluding the 1st rootstock). This method was 

also tested at sampling intensities of 1, 2.5, 

and 5 points per acre (3 rules). Therefore, a 

total of 42 sampling rules was evaluated. 

Hardwood crown diameter and cross-sectional 

area were used in this study rather than stem 

diameter and basal area because of the relatively 

small stem sizes and the problem with multiple 

stems per hardwood rootstock common in young pine 

plantations. Crown measurements may also be good 

indicators of competitive stress exerted on the 

pines by the hardwoods. The relatively low 

sampling percentages (-1 percent or 1, 2.5, or 5 

sample points per acre) were chosen out of 

practicality. Although greater sample intensity 

should yield better results, the practical 

limitations of time and manpower that would be 

expended in a field application of these 

techniques dictate relatively small samples. 

Estimates of number of hardwood rootstocks per 

acre (NRPA), sum of total hardwood rootstock 

heights per acre (STRH), and sum of hardwood 

crown areas per acre (SCA) were computed for each 

stand sample Cstand entry). These var ialiles were 

chosen because they may be used as measures of 

competition if they are shown to be well 

correlated with pine growth losses. A stand 

entry estimate was based on 16, 40, or 80 

randomly located sample points Cplots). Standard 

errors of the stand entry estimates were 

calculated for all sampling methods except for 

Batcheler's. Sampling ceased after 200 stand 

entries or if the mean of all stand entry 

estimates of NRPA did not differ by more than 

0.5 percent for 10 consecutive stand entries. 3 

Relative bias (R), variance, percentage of 

estimates falling within 5 percent of the true 

value (3?5), and consistency of the estimators were 

used to evaluate the 42 sample rules (Schreuder 

and Thomas 1985). These criteria were chosen for 

several reasons. An unbiased sampling rule is 

desirable. Since variance is used to estimate 

the sample size necessary to achieve a desired 

3~opies of both sampling and stand simulators 

are available from either author. 

allowable error, low variance is desirable. High 

precision in a sampling estimator is also 

desirable. If it is not possible to gather an 

adequate sample, an estimate from an unbiased 

high precision method should be sufficient . 

R was defined as the ratio of the sample 

estimate to the true value. Due to the differing 

populations, variance was expressed as the mean of 

stand entry standard errors divided by the true 

value (CV), and consistency (C) was defined as the 

standard error between stand entry estimates 

divided by the true value. An analysis of 

variance (ANOVA) was used to detect spatial 

pattern, population density, sampling method, and 

sampling intensity effects on R and P5. The 

.&NOVA was used to identify "robust" sampling 

rules, i.e, a sampling rule unaffected by spatial 

pattern or population density. 

RESULTS 

In general, the responses of each of the 

estimators for NRPA, STRH, and SCA with respect 

to R, PS, CV, and C were similar. For 

illustrative purposes, NRPA estimators will be 

discussed. 

Relative bias (R) for all fixed area and 

polyareal methods approached 1. This indicated 

that the methods were relatively unbiased at low 

sampling intensity. Based on the ANOVA, 

estimates using Batcheler's method were 

significantly (.P = 0.01) affected by pattern. R 

was generally less than 1 for uniform populations 

and greater than 1 for clumped populations. 

Other work has shown that more intensive sampling 

reduces the bias of this method (Batcheler and 

Hodder 197 5) . 

The ANOVA showed that P5 for the fixed area 

methods was strongly affected by spatial pattern 

and population density. P5 was highest for 

uniform populations and lowest for clumped 

populations. For example, P5 for 0.01-acre 

clrcalar plots for 3-year-old, low density 

populations was 70 percent, 35 percent, 23 

percent, and 20 percent (vniform, random, lightly 

clumped, heavily clumped), respectively. 

Relative precision (P5) was highest for the 

polyareal methods. Of the polyareal methods, 

horizontal line sampling usually had the higher 

P5 values. In general, increasing population 

density increased relative precision for all 

fixed area and polyareal methods. This was due 

to an increased number of rootstocks being 

measured at each sample point, 

CV for the polyareal methods was lower than for 

the fixed area methods. Ae Oderwald (1981) 

proved, variance was lowest in unif om 

populations and highest in clumped populations. 

Increasing population density reduced CV as more 

rootstocks were sampled at each point. In this 

study, horizontal and vertical line sampling 

variances were lower than for the polyareal point 

sampling rules. . The effects of pattern and sampling intensity on 

C were similar to those on CV. As sampling 
intensity increased, C hproved and CV 

decreased, C was highest for the polyareal 

methods. 

DISCUSSION AKD RECOMENDATIONS 

Increasing the number of rootstocks sampled 

would have improved the performance of all 

sampling rules examined, An increased number of 

rootstocks sampled at each point would have 

reduced the amount of variation between sample 

points (CV) and reduced the amount of variation 

between stand entry estimates CC). This also may 

have been accomplished by increasing plot sizes, 

reducing CF's and vertical angles or by 

increasing the number of sample points per acre. 

Fixed area plot estimates are theoretically 

unbiased and are "workable" in dense stands. 

Fixed plot boundaries facilitate the selection of 

sample rootstocks. The relatively poor 

performance of fixed area methods in comparison 

to polyareal methods in this study can be 

attributed to two factors. Fewer rootstocks were 

sampled in fixed area sampling than in polyareal 

sampling (Sukwong et al. 1971). Secondly, the 

plot sizes used may have been too small. 

Increasing plot sizes to 0.01 acre might have 

reduced the effects of density and pattern on P5, 

CV, and C for fixed area plots. However, this 

may not be practical as the amount of time spent 

at each sample point would increase substantially. 

An average of 50 rootstocks would be sampled at 

each point in the populations with densities of 

2500 rootstocks per acre. 

Given the conditions of this study, horizontal 

line sampling (LOO GF) appears to Ee the best 

method to use to estimate the three variables of 

interest (Table lj. This study showed that the 

method is relatively unbiased at low sampling 

intensities, Additionally, nearly 100 percent of 

all horizontal line estimates fell within 5 percent 

of the true value. The coefficient of variation, 

and consequently the variance, associated with the 

estimate was the lowest of all methods examined. 

Thus, horizontal line sampling should require the 

least number of sample points to achieve a 

specified allowable error of all methods studied. 

The use of horizontal line sampling to provide 

information about the level of competing hardwood 

vegetation in loblolly pine plantations is 

promising. The method is accurate and objective. 

However, field testing of this method needs to be 

conducted. Field tests will illustrate the 

practicality of the method as well as aiding in 

development of equipment (Cooper 1957). Once 

this step is completed, the subjectivity that is 

now of ten required in plantat ion evaluation may 

co longer be necessary. 

Table 1 .--Performance of sampling rules used to estii,~ate nunber* of rootstocks 

per acre for a sinulated thl-ee-year-old, heavily ciuuped, lor? density, 

hardwood rootstock population. 

1 Coefficient4 Consi~:;ency 5 Samy 1 ing Rule Relat3ve Relative 

Bias precision3 of Variation 

-. - Percent; ?ei*cetl'i i'e r-cen t 

C 

N 

IIP 

I& 

VP 

VL 

B 

'C - 0.01-acre circuiar plot (1 percent szrlpling intensity) 

R - 0.01-acre rectangular plot (1 peracent sa;.lpiini; intensity) 

HP - horizontal polnt (CF = 100, 5 pt/acre) 

HL - horizontal line (CF = 100, 5 pt/acre) 

VP - vertical point (vert. ang. = 3g0, 5 pt/acre) 

VL - vertical line (vert. ang. = 30 , 5 ptlacre) 

B - Batcheierls triple distance (5 pt/acre) 

2~atio of estiwate of luean to true ncan 

'pei*centWe of esti:~ates within 25 percent of true :,lean 

'~atio of average otandai-d error to true Mean 

'~atio of standard error betweon starid entry estimates to true i,:ean 
LITERATURE ClTED 

BatcheZer, C.L., an2 R.A.C. Hodder. 1975, 

rests of a 2istance technique for inventory of 

pine plantations, Kew Zealand Journal of Forest 

Science 5(L) : 3-17. 

Cooper, G.F. 1957. The variable plot method for 

estimating shrub density, Journal of Range 

Management 10:llL-115. 

Grosenbaugh, L.R. 1958, Point-sampling and 

line-sampling : probability theory, geometric 

ixnplicat ions, synthesis. Occ. Pap, #160. USDA 

For, Serv., South. For. Exp. Sta, 

Nusch, B,, C.1. Xiller and T.W. Beers. 1982, 

Forest >fensuration, 3rd ed. John WiLey and 

Sons, 402 pp. 

Kaltenberg, 3.C. 1978, Evaluation of 

regeneration sazpling methods: A Monte Carlo 

analysis using simulated stands. Wash. Dept. of 

Kat. Res. Rep. 39, Olympia, MA. 50 pp. 

Oderwald, R.C. 1981. Comparison of point and 

plot sampling basal area estimators. Forest 

Science 27(l) :42-48, 

Palley, M.N. and W.G. OQegan. 1961. A 

computes technique for the study of forest 

sampling methods: I. Point sampling compared 

with line sampling. Forest Science 7(3):282-294. 

Pielou, E.C. 1977, Xatheaatical Ecology, John 

Xiley and Sons, Xew iork. 355 pp. 

Schreuder, W.T. and C.E. Thomas, i985, 

Efficient sampling techniques for timber sale 

surveys and inventory updates, Forest Science 

31(4j:851-866. 

Sukwong, S., W.E. Frayer and E.W. Xagren. 1971. 

Generalized compar isons of the precision of 

fixed radius and variable-radius plots for 

basal area estimators. Forest Science 

17:263-271. 

Warren, W.G. and G.L. Batcheler. 1979, The 

density of spatial patterns: robust estimation 

through distance methods, &: Spatial. and 

temporal analysis in ecology (R.M. Cormack and 

J.K. Ord, eds.) pp. 247-270. Tnt. Coop. Publ. 

Rouse, Fairland, MD. 

Meise, D.R. and G.R. Glover. (In preparation) 

Simulation of hardwood rootstock populations in 

young Zoblolly pine plantations, 

Zutter, B.R., G.R. Glover and D.F. Bickens. 

1985. Competing vegetation assessement systems 

in young southern pine plantation. z: Proc. 

Third Bien. Silvic. Conf. (E. Shoulders, ed.), 

pp. 279-286. USDA For, Serv. Gen. Tech. Rep. 

SO-54, New Orleans, LA. 
SIMULATING THE EFFECT OF HARDWOOD ENCROACHMENT 

ON LOBLOLLY PINE PLANTATIONS L/ 

W, D. Smith and W. L. Hafley 

"Prom habit rather than as a result 

of natural processes we are inclined 

to conceive of the most desirable 

forest Lo '$e one with fully stocked 

stands of a preferred species," 

Ralph PI. Marquis (1947) 

Abstract.--A procedure suggested by Schumacher and Coile for dealing with 

the effect of hardwood competition is incorporated into a growth and yield model 

for Loblolly Pine plantations. Their procedure was based on the assumption that 

the hardwood basal area would effect the pine growth to the same extent as 

additional pine basal area. That assumption was modified to reflect the 

difference in basal area carrying capacity between pine and hardwood on the same 

site. The model simulates the impact of hardwood encroachment by either a 

decurrent or excurrent species based on, 1) actual pine and hardwood basal area 

or 2) percent hardwood composition, at any given age. The assumptions and their 

implied biological responses are discussed, The veracity of the procedure is 

tested against a 24 year old site preparation study in Fayette, Alabama. An 

example of an economic evaluation of hardwood control is presented. 

INTRODUCTION 

There has long been an interest in estimating 

the impact of hardwood on the growth of pine in 

regard to predicting pine yields, Schumacher and 

Coile (1960) suggest that one simply add the 

hardwood basal area to the pine basal area, 

project the total as pine, and reapportion it to 

the respective species. The inherent problems in 

that approach are the implied assumption that pine 

and hardwood grow at the same rate, hence the 

relative proportions will remain constant; and 

that one square foot of hardwood basal area is 

equivalent to one square foot of pine basal area. 

However, their suggestion is not all together 

inappropriate. Given a hard wood growth function 

and an estimate of the competitive relationship 

between pine and hardwood their suggestion seems 

quite rational. Starting from Schumacher and 

Coile's suggestion we have evolved a simulation 

procedure for use with pine plantations and which 

we have incorporated into the North Carolina State 

University Managed Loblolly Pine Plantation Growth 

and Yield Simulator, 

While there appear to be a number of studies 

where hardwood in pine stands was of interest a 

great many of these have inconsistencies of 

measurement such that tracking of the performance 

of hardwood over time is not possible. Without a 

consistent measure of the hardwood component, the 

interpretation of the pine performance becomes 

meaningless. In many instances where hardwoods 

have been treated, there was either no record of 

how many hardwood were there or whether or not 

they were killed. In the face of what appears to 

be conflicting results due to inadequate data 

recording we had no choice but to develop a 

rational simulation of the hardwood impact. We 

will present here our underlying assumptions, the 

biologic outcomes of those assumptions, an 

evaluation of the veracity of the model and, 

finally, an example of an application of the 

model. 

The two most valuable contributions of 

simulation are the expansion of the applicability 

of existing knowledge and the identification of 

gaps in that knowledge. Much of the existing 

knowledge regarding the impact of hardwood 

encroachment is of a qualitative nature 

encorporated into the intuition and experience of 

a number of foresters. What we present here is 

the result of discussions we have had with a few 

of these individuals in which we interacted on our 

ideas for simulation. 

BASIS FOR SIMULATION 

- l/ Paper presented at the Fourth Biennial South- The simulation is based on three models. One, 

ern Si lvicultural Research Conference, Atlanta, the North Carolina State University Managed 

Georgia, November 4-6, 1986, Lohlolly Pine Growth and Yield Simulator, which we 

- 21 W. D. Smith, Lecturer of Forestry, and W, L, will refer to from here on as "the model" is based 

Hafley, Professor of Forestry and Statistics, on predicting, 1) the minimum, mode, maximum, and 

Department of Forestry, North Carolina State standard deviation of height and diameter of 

University . 
stands over lime, where those characteristics are 

functions of dominant height and growing space 

folloa#ing initial survival, and 2) survival, which 

is a function of dominant height, site index, and 

growing space. The other two models are hardwood 

basal area projection models, in which basal area 

is a function site index, age, and initial basal 

area, 

The two hardwood models are intended to 

represent different crown shapes. In modeling 

mixed stands the true ratio's of the species in 

the mixture must be correctly represented. This 

ratio is not identical to the ratio of basal areas 

but more correctly represented by the relative 

area occupied by their crowns (Assman 1970). Two 

different hardwood models are required to reflect 

the different crown area and growth rate of the 

hardwood species present. The model for a 

decurrent species is based on the upland oak data 

published by Zahner and Myers (3.934) to which we 

fit a Richards function (Richards, 1959). The 

parameters of the Richards function are themselves 

functions of site index and initial basal area. 

The model for an excurrent species was developed 

by Kenney (1984) for bottomland sweet gum based on 

data of the NCSU Cooperative Hardwood Program and 

is also a Richards function whose parameters are 

expressed as functions of site index and initial 

basal area. 

ASSUMPTIONS 

Given the above models we then made several 

assumptions regarding how hard wood competition 

would effect the height and diameter growth and 

the mortality of the pines. The basic approach is 

an adaptation of the method we used for simulating 

thinning (Smith and Hafley, 19841, It is based on 

a very simple assumption developed in South 

Africa by A. J. O'Conner, 1935 (Burgers, 1971) 

called the correlated curve trend (CCT) method. 

O'Conner suggested that the increment in a 

plantation thinned to n trees per acre will be 

equal to some coefficient times the increment of 

an unthinned plantation of the same number of 

trees per acre. Mathematically this is expressed 

as 

where t = thinned plantation , u = unthinned plantations t 

n = trees per acre v 

When applied to basal area per tree 

increment, Cr can be assumed to be equal to 1. 

Figure 1 presents a graphical representation of 

the concept and its impact on average stand 

diameter. 

For the hardwood impact we used the same 

basic method, We assume that increment in a 

plantation of n pine trees per acre, with a 

hardwood component equivalent to rn pine trees per 

acre, will be equal to some coefficient times the 

increment of a plantation with n + m pine trees 

per acre and no hardwood component. 

Mathematically this is represented as 

Figure I. 

DIAMETER RESPONSE TO THINNING 

where h = plantation with hardwood v 

u = plantation without hardwood , n = trees per acre * 

m = equivalent pine trees per acre , 

Again we assume Cr to be equal to 1. Figure 2 

presents the impact of this modified CCT on 

average stand diameter. 

Now since the CCT method, and the model, is 

based on number of trees per acre we need a 

mechanism for determining m, given hardwood basal 

area. Basically, we are asking how many pine 

trees represent the same competitive effect of a 

certain quantity of hardwood. Remember, we have a 

hardwood model that projects basal area and we 

have a pine model based on trees per acre, and we 

have to come up with some procedure to relate the 

two. If we were to assume crown area per unit of 

basal area for the two species was equal we could 

divide the hardwood basal area by the average pine 

basal area and find the equivalent number of pine 

trees. However, given that competition for crown 

space is important we do not accept a one to one 

relationship between pine and hardwood basal area. 

The approach we used to estimate the 

equivalence bet ween pine and hard wood basal area 

was to compare the maximum basal areas predicted 

by the growth models. The assu. ption is that at 

maximum basal area the site is fully occupied by 
Figure 2. Figure 3. 

DIAMETER RESPONSE TC HARDWOOD 

r- i 

5 10 15 20 25 30 35 

AGE 

the species, and since crown size is directly 

related to basal area the ratio of basal areas 

would give us the ratio of crown space occupied by 

a square foot of each species. Figure 3 is a 

plot of maximum basal area against pine site index 

for the three models. Using this relationship we 

then calculate the equivalent number of pine trees 

from the relationship 

where HBA = hardwood basal area I 

PBA = average basal area per pine tree, 

HADJ = the adjustment factor from the 

ratio of maximum hardwood basal 

area to maximum pine basal area. 

Consider the following example. Suppose we 

had a plantation that had 595 trees per acre with 

an average diameter of 2.5 inches and a hardwood 

component representing 8 square feet of basal 

area. Further, assume that the hardwood to pine 

ratio for the site index of the stand is 0.77, 

then ; 

and we would say that a pine stand of 595 trees 

per acre with 8 sq ft of hardwood will have an 

increment equivalent to a pure pine stand with 911 

trees per acre. 

This method is applied to the growth of the 

modal and minimum values of height and diameter 

used in the model. Growth of the maximum height 

and diameter are assumed to be uneffected by the 

hardwood. Figures 4, 5 and 6 graphically 

45 55 65 75 

PINE SiTE INDEX 

demonstrate the hardwood impact on the height and 

diameter characteristics. Since diameter growth 

is a function of height growth in the model, 

Figure 5 shows dominant height on the abscissa. 

In the model, dominant height is defined as the 

mean of the 100 tallest trees per acre. The 

impact of the height growth pattern on diameter is 

then presented in Figure 6. The reduction in the 

maximum diameter shown in Figure 6 is a result of 

the impact of the hardwood on the height 

distribution and the resulting reduction of 

dominant height over time. Finally, using this 

same method the mortality of the pine was 

developed. The mortality, CY, of the pine in a 

plantation containing hardwood is determined by 

apportioning the mortality, AX, in an equivalent 

pine plantation to the pine, Figure 7 

demonstrates the procedure, The relationship is: 

Figure 4. 

IMPACT OF HARDWOOD COMPETITION 

0 r 

5 10 15 20 25 30 35 

RGE 
Figure 5. 

IMPACT OF HARDWOOD COMPETITION 

Figure 6. 

IMPACT OF HARDWOOD COMPETITION 

Figure 7, 

HARDWOOD IMPACT ON SURVIVAL 

----_ g60e ] ,.- 1SOQ 

'. 1900 \ A Y *AX *[PINE tpa) I fPINE tpa * WOW0 tpa) 

-\ 

where, n = number of pine trees per acre, 

m = equivalent pine trees per acre as 

determined in equation 3. 

BIOLOGICAL OUTCOME 

What then is the biological impact of these 

assumptions? Figure 8 demonstrates the 

performance of hardwood as a percent of total 

basal area over time based on its percent of total 

basal area at age 5, The initial vigor of the 

sprout growth contributes to the hardwood 

representing a large portion of the total basal 

area early in the life of the plantation, As the 

pine growth begins to accelerate the hardwood, as 

a percentage of the total basal, area declines. 

At about age 12 it becomes relatively flat and 

remains that way until about age 22. At that 

stage of development, mortality in the pine 

component results in a rapid decline in pine basal 

area growth, and hardwood basal area teaches the 

stage of rapid growth. As a result the percent 

hardwood in the stand begins to increase. 

Figure 9 shows the relative total basal area 

for a pure stand of the decurrent hardwood 

species, a pure pine plantation, and a pine 

plantation with 40Z of the total basal area in 

hardwood at age 5. The plantation was assumed to 

initially have 595 surviving stems per acre at 

establishment on a site index 65 feet (base age 

25). The diSference between the lines will differ 

with site index, but basically the pine plus 

hardwood will be less than the pure pine until we 

pass the age at which the pine basal area attains 

its maximum and begins to decline. 
Figure 8. Figure 11. 

WWWD AS PERCENT OF TOTAL H 

VERSUS ACE D 

IMPACT ON DOWhT HEIGHT 

AT &WEX ACE 25 

( SITE INDEX 65 J 

::::::--------4 

5 7 9 11 13 15 17 19 21 23 25 27 29 31 33 35 

AGE 

Figure 9. 

BASAL AREA VS. AGE 

SQ. FT. 

200 PINE 

PINE + HDWD 

150 

HDWD 

100 

5 0 

0 

AGE 

The impact on volume is demonstrated in 

Figure 10. Again the original pine stand had 595 

stems per acre at establishment on a site index 65 

feet (base age 25). The figure shows the relative 

impact of increasing hardwood basal area as a 

percent of total basal area at age 5. 

Figure 10. 

PINE VOLUME VS. AGE 

%i-c'"w. 

AGE 5 

We mentioned earlier that the impact of 

hardwood on the height distribution creates a 

reduction in dominant height, defined as the 

height of the tallest 100 trees, at index age 25. 

Figure 11 presents that impact for the pine 

plantation used in Figures 9 and 10. A hardwood 

basal area to 60% of total basal area at age 5 

results in a 5 foot reduction in dominant height 

at index age 25, 

55 1 i 

0 10 20 30 40 50 60 

% H ARDWOOD A G E 5 

Figure 12 presents the impact of hardwood 

over time based on site index for the same example 

plantation with the hardwood at age 5 representing 

40% of the total basal area. This demonstrates 

that on a poor site the competition from hardwood 

is less than on higher sites. On a pine site 

index 45 feet (base age 25) 40% hard wood at age 5 

results in a 20% reduction in pine volume at age 

35, while on a pine site index 85 there is a 40% 

reduction. 

Figure 12. 

HARDWOOD AS PERCENT OF TOTAL 50 VERSUS AGE 

45 ( 40% HDWD AT AGE 5 ) 85 

40 T 

35 65 

I 30 N 

% 25 45 D 

E 

20 X 

15 

10 

5 

0 

5 7 9 It 13 15 17 19 21 23 25 27 29 31 33 35 

AGE 

Finally, Figure 13 presents the impact on the 

diameter distribution. Again the data are for the 

example plantation. The effect of hardwood is to 

create a more right skewed distribution of 

diameters. As shown in Figure 6 the maximum is 

reduced as a result of reduction in dominant 

height and, the mode and minimum values are 

reduced by the presence of hardwood basal area and 

its effect on dominant height. The data graphed in 

Figure 13 are class mid points. The actual values 

of the three characteristics at age 30 are: 

Maximum 

Mode 

Minimum 

No Hardwood With Hardwood 

(inches) (inches) 

12.6 12.2 

9.0 8.3 

4.7 4.5 
Figure 13. Figure 14. 

NPV (i - 0.061 vs % HARDWOOD AGE 5 %PACT OF HARDWOOD ON DLMvETER DISTRIBUTION AT AGE 30 

\ NOHARDWOOD 

D~cUlsS 

VERACITY 

As indicated earlier there is very little 

long term data on which to test the outcome of our 

assumptions. One data set that was made available 

to us belongs to the Auburn University 

Silviculture Herbicide Cooperative and is located 

at Fayette, Alabama. The objective of the study 

was to evaluate different methods of mechanical 

and chemical site preparation. Percent hardwood 

was not recorded for earlier years but at age 12 

ranged from 4 percent (3 sq ft) for a bulldozer 

and pile treatment to 76 percent (34 sq ft) for a 

hand injection treatment. We input the stand 

conditions of each plot at age 12 and predicted 

the stand conditions at the age 24 measurement. 

Table 1 presents a summary of the statistics 

comparing the observed and predicted values for 

the 21 plots. 

Table 1. Summary statistics for comparison with 21 plots 

from the Fayette, AL study. 

Avg. * Mean Abs. 2 Explained 

Variable Diff. Range Diff. Variation 

Trees/ac . 14.6 -119 to 74 27.6 89.0 

Ddh (in.) 0.3 - .4 to 1.6 0.49 81.1 

PineBA(ine2 7.8 - 4to22 9.0 97.3 

Hdnd BA (in.2: - 7.1 - 34 to 11 8.2 84.9 

Difference = Observed - Predicted values at last measurenrent. 

ECONOMIC ANALYSIS 

The quote at the beginning of the paper is 

from a paper titled "Folklore and Bromides in 

Forest Economics", Marquin, 1947. To test the 

often held assumption that all hardwood should be 

killed the product output from the model was input 

into QUICK-SILVER (Vasievich et a1 1984). The 

yield for a stand with 40 percent hardwood with 

and without hardwood conLrol at age 5 is 

presented in Tables 2 and 3, respectively, with 

the associated costs and revenues. Figure 14 

presents the net present values after tax for 

treated and untreated stands having 10 to 60 

percent hardwood at age 5. The results assume a 28 percent marginal rate for ordinary and capital 

gains income, a 10 percent tax credit, 

amortization of establishment costs, and expensing 

of treatment costs. The analysis assumes 

utilization of the hardwoods. Annual costs are 

not included. The stumpage values used were 

regional acreages and do not reflect other impacts 

of hardwood that may occur, such as increased 

logging cost. 

X HARDWOOD AT AGE 5 

Table 2. 

NORTH CAPOLIUA STATE UNIVERSITY PLANTATION MANAGEMENT SIMULATOR 

Y I E L 0 T A 8 L E f Loblolty Plne ) 

----------------------------------------------------------------------------- SITE INDEX PLANTING OENSITY PERCENT PLANTING INITIAL SURVIVAL 

(EASE AQE 25) (STEMS/ACRE) 

06 700 

SURVIVAL 

05 

ISTEMSlACREI 

595 ............................................................................. CCM AVfl AVE BASAL AREA TOTAL MA1 PA1 

AGE WT TPA Dl* MT PINE HDWO VOLUIE 

yra ft ln ft rp rt CU ft(lbt ----------------------------------------------------------------------------- 

"0 P&EN:g:F T:~lHAROWd~ BASAL :RE* HA: EEEN REd:EO 3 

10 29 692 4.1 20 64 1 499 60 96 

16 43 572 0.0 39 113 1 1574 105 215 

20 5s 520 7.2 50 1st I 2002 133 218 

25 04 473 0.1 67 106 2 3426 137 153 

30 70 428 0.6 03 173 2 3875 129 SO ............................................................................. 

NOTE: WEIOHTIA5E CURVE FRCU WLOENET AL. 

SOUTH. JOUR. APPL. FOR.. 1961 

HARP*OOD TYPE -- OECURRENT 

FORESTRY INVESTMENT AfJALYSIS ............................ '*a QUICK-SILVER <a< 

TRANSACTIONS FOREST SOUTHEASTERN CENTER FOR ECONOMICS RESEARCH 

FILE-HW(O40T Econalca of HarQrwd Menapement In Plne Plantations 

PREPARE0 8Y: W. 0. 31111th OATE: 29 OCT 1906 

-----------------*------*------*-m------*---m--*-------------*-*-------- 

LO~IOIIY Plne Plantatton s1(201 - 06 

s~te Pre~ by chop and 8urn - Plant 700 t/a 

NO THINNING - 30 YEAR ROTATION 

40 1 Hardwood at ape 5 - 60 % COntrOll*d at ape 5 

.11------*---------------------------*-----------m----------------------m 

FIRST LAST STEP CURRENT RATE OF 

m. ACTIVITY YEAR YEAR YEARS VALUE CHANOE QUANTITY UNITS 

TAX CLASS (9IUNlT) (XIYR.) f PRODUCT) 

------------------------------------..----------------------------------- 1 SITE PREP 0 0 0 -05.00 0.00 1.00ACRES 

REFORESTATIO* M*+ 

2 PLANTINQ 

- --. 0 0 0 -70.00 0.00 1.00ACRES 

REFORESTATION COST 

3 HER8IClDE 

ORDINARY EXPENSE 5 0 -50.00 0.00 1.00 ACRES 

4 FINAL H'VEST 30 30 0 130.00 0.00 2.20 MBF 

TIMBER SALE SAWT IMBER 

6 FINAL H'VEST 30 30 0 38.50 0.00 14.00 CUNITS 

TIWER SALE CHIP-N-SAW 

0 FINAL H'VEST 30 30 0 11.00 0.00 15.60 CWlTS 

TIMBER SALE -----------------a- -----. - ---------------*-----*------------- ::::z:*- SCMEOULlC W CASH FLOWS ------------------------------------------------------------------------ COST REVENUE CUAULATIV 

YEARACTIVITY (XIANTITY UNITS 

f PROOUCT 

AMOUNT AMOUNT 

(1) f t ) 

TOTAL 

(S) ........................................................................ 0 SITE PREP 1.00 ACRES 

0 PLANTINO -06.00 

-70.00 

-65 .OO 

b HERelClOE 1:: 2::; 40. 00 -140.00 

3OFlWALH'VES 2.20 WF 206.00 -1 90 00 

(SAWTIWERI 96 00 

30 (CH FINAL IP-N-SAW) H'VES 14 .OO CUN1 TS 

30 FINAL H'VES 15.00 CUNITS 

(PWPW000) 

------------.-----*---*---.----------.------*--*----.---------.------.-- 

AFTER -Axes 

......................................................................... 

OISEXWNT RATE tl) 4 OW 8 000 8 000 10 000 12 00 

......................................................................... 

PRESENT VALUE (COSTS) -205 39 -224 90 -201 20 -160 71 -177 6 

PRESENT VALUE (SENEFITS) 360 03 220 06 150 18 107 28 61 6 

PRESENT NET WORTH 96 45 1 70 -50 32 -79 44 -95 8 

BENEFlTlCOST RATIO I30 101 075 057 04 

ANNUAL EOUIVALENT VALUE 5 52 0 12 -4 47 -6 43 -11 % 

CWPOSITE RATE OF RETURN 5 07 0 03 0 97 7 89 9 1 

INTERNAL RATE OF RETURN 6 06 6 05 6 05 6 05 6 0 
Table 3. SUMMARY 

sourn CAPOLIIA STATE UWIVEBSITY PLdk8TAT:CW WAWAGEIEHT SIICLATOY 

Y iE LO TAB i E I Lobioi~YCind i ............................................................................. 

SITE INDEX PLANTINQ OENSrTY PERCENT PLANS'NG INITIAL SIIPVIVAL 

(BASE *0(1 25) (STDISIACRE) SURVIVAL tSTEMS/ACRE, 

65 -- 700 85 505 

^_____--_-----~--*---------------------------------------------------------- 

3. , AYE BBSAL AREA TOTAL MA1 PA* 

l5E MOT PINE HOW0 VOLOIE 

yra tt -- in ft ra ft cu fttlb) -___-------*-t--------------------------------------------------------------- 

MTE: kiEtOWTIAQE CURVE FROM OOLDEN ET AL 

SOUTH. WUR. APPL. FOR.. 1981 

WARWOD TYPE -- DECURRENT 

FORESTRY INVESTMENT ANALYSIS ---------------------------- ,rr QUICK-SILVER <c< 

TRANSACTIONS 

SOUTHEASTERN CENTER FOR 

FOREST ECONCUICO RESEARCM 

FILE-HOWO~OU Econmlcr of narawood Managanent in Pine Plantations 

PREPARE0 BY: W. 0. Ynlth DATE: 29 QCT !988 

.--.--.*--.l------------*--.--------m-*-----------.-.----.-.------------- 

Loblolly Plna Plantation S1(25> - 65 

Slta Pr.0 by ChOO and Burn - Plant 700 tla 

NO THINNIM - 30 YEAR ROTATION 

40 % WArdwOOd at 600 5 - No Hardwood Control 

FIRST LAST STEP CURRENT RATE OF 

W. ACTIVITY YEAR YEAR YEARS VALUt CHANOE QUANTITY UNITS 

TAX CLASS ($/UNIT) (%/YR.) ( PROOUCT ) 

------------------------------------------------------------------------ 1 SITE PREP 0 0 0 -55.00 0.00 1.00ACRES 

REFORESTATION COST 

2 PLANT IM 0 0 0 -75.00 0.00 1.0OACRES 

REFORESTATION COST 

3 FINAL H'VEST 30 30 0 130.00 0.00 1.20 MBF 

TIMER SALE SAWT iM0€R 

4 FINAL W'VEST 30 30 0 36.50 0.00 10.30 CUNlTS 

TIMER SALE PYIII-L~-~AYI - .- O FINAL W'VEST 30 30 0 11.50 0.00 13.70 CUNlTS 

TIMBER SALE PULPWOOD 

OFINALH'VEST 30 30 0 1.00 0.00 26.40TONS 

TIMER SALE HAPCmMO 

SCHEWCE OF CASH FLOWS ------------------------------------------------------------------------ COST REVENUe CUMULAT I V 

YEAR ACTIVITY QUANTITY UNITS 

( PROOUCT ) 

WUNT WUNT 

(3) (S) 

TOTAL 

it ------------------------------------------------------------------------ 0 S lTE PREP 1 .OO ACRES 

0 PLANT INQ 1 .OO ACRES 

-65.00 

-75.00 

-86. 00 

30 FINAL H'VES 1.20 MBF 156.00 - 140.00 

(SAWT IMZIER) i8.00 

JOCINALW;VES 13.70 CUNITS 

( PULPwmO ) 

30 FINAL W'VES 20.40 TONS 

AFTER TAXES ......................................................................... 

DISCOUNT RATE (2) 4.000 6.000 8.000 10.000 12.00 

PRESENT VALUE (COSTS) -2Ol.ClO -174.90 -159.92 -161.49 -146.8 

PRESENT VALUE (BENEFITS) 289.01 170.84 115.47 83.88 84.9 

PRESENT NtT WORTH 67.21 -4.06 -44.46 78 -81.7 

OENEF I ?/COST RAT I0 1.33 0.98 0.72 0.35 0.4 

ANNUAL EOUiVALENT VALUE 3.8s -0.29 -3.96 -?.20 -10.1 

CWPOSITE RATE OF RETURN 5.00 6.92 6.63 7.84 9.0 

INTERNAL RATE OF RETURN 5.85 6.85 5.85 5.85 6.8 

We have presented a rationale for evaluating 

the impact of hardwood competition in pine 

plantations along with the implications of that 

rationale. Without further, more detailed, data 

the best evaluation of these results is that they 

reflect the biology of the situation as we 

understand it. 

LITERATURE CITED 

Assman, E. 1970. The principles of forest yield 

study. Pergamon Press, N.Y. 506 p. 

Burgers, T. F. 1971. The correlated curve trent 

(C. C, T.) method used for growth prediction 

in thinned stands of pinus patula. Forestry 

in South Africa. 12:ll-17. 

Kenney, R. M. 1983, A growth and yield model for 

natural stands of Piedmond bottomland 

hardwoods. Unpublished M. S. Thesis. N. C. 

State University, Raleigh, N. C. 47 p. 

Marquis, R. W. 1947. Folklore and bromides in 

forest economics. SAF, Division of For, 

Econ., Proceedings:76-81. 

Richards, F. J. 1959. A flexible growth function 

for emperical use. J. Exp. Bot, 10(29):290- 

300. 

Schumacher, F. X., and T, S. Coile. 1960. Growth 

and Yields of Natural Stands of the Southern 

Pines. T. S. Coile, Inc., Durham, N, 6, 115 

PP * 

Smith, W. D. and $4. L. Hafley. 1984. Evaluation 

of a loblolly pine plantation thinning model. 

SJAF 19(1):52-63. 

Vasievich, J. M., R. Frebis and R. W. Wiethe. 

1984. The Forest Investment Analysis 

Program. Southeastern Center for Forest 

Economics Research. Durham, N. C. 

Zahner, R. and R. K. Myers. 1984. Productivity 

of young Piedmont oak stands of sprout 

origin. SJAF 8(2):102-108. 
Seedling Production 

Moderator: 

Robert C. Keilison 

North Carolina State University 

THE LNEZUma OF SEEDBED DENSITY ON LOBLOLLY AND 

James N. Boyer and David B. south2/ 

Abstract.--Since the 1930ts, several investigators 

have studied the effect of seedbed density on loblolly and 

slash pine seedling morphology. The purpose of thrs paper 

was to compare the data from these studies and to show the 

general relationship between seedbed density and the distribution of seed1 ing grades. Seed1 ings were classified into 

three grades (grade 1, grade 2, and cull) based solely on 

root-collar diameter. For each study, models were developed 

to predict the proportion of seedling grades for a given 

density, These models varied depending upon the particular 

study, nursery, or species, It is hypothesized that biological and cultural conditions such as f er ti1 ity , undercutting, irrigation, date of sowing and date of lifting 

influence these curves. 

Keywords : Root-collar diameter, seed1 ing morphology. 

Morphological grades for loblolly (Pinus 

- taeda L,) and slash (Piaus ellisttii var 

elliottii Engelm.) seedlings suggested by Wakeley 

(1954) were based upon root-collar diameter, 

among other factors. A grade I seedling must be 

4.8 millimeters or greater, and a grade 2 

seedling is 3.2 millheters or greater. 

Seedlings with a diameter less than 3.2 

millimeters (grade 3 seedl ings ) are considered 

culls. 

Several studies have shown that grade 1 

seedlings can show increased growth aver lower 

grade seed1 ings (south and Hexal 1984) , yet 

southern forest nurseries produce very few grade 

1 seedlings (South et al. 1985). A recent survey 

of 53 southern forest nurseries revealed that 

most loblolly pine seedlings produced today are 

grade 2 or less (Boyer and South 1986). Half of 

the nurseries surveyed produced 4 percent grade 1 

or less. Marx et al. (1984) reported many 

nurseries producing more than 10 percent culls. 

Final seedbed density for loblolly and slash pine 

exceeded 300 per square meter in 80 percent of 

the studies. 

ll~resented at the Fourth Biennial Southern 

S ilvicul tural Research Conf erence in Atlanta, 

Georgia, November 4-6, 1986. 

2/~esearch Associate and Assistant 

Professor, Auburn University Southern Forest 

Nursery Msnsgement Cooperative, School of 

Forestry, Auburn University, AL 36849-4201. 

Operational grading of southern pine 

seedlings is not currently done at any forest 

nursery, although some nurseries do cull small, 

def omed or diseased trees. Bowever, several 

research studies have demonstrated how seedbed 

density affects the distribution of seedling 

grades (Burns and Brendemuehl 1971; Shoulders 

196 1; Negben and Meyer 1986) , Barns and Langdon 

(1977) and May (1933) described the effect of 

density on overall seedling morphology. Other 

data on these effects remain unpublished. 

The objective of this paper was to bring 

together data fram these published and 

unpublished studies and create models which show 

how the distributions of loblolly and slash pine 

seedlings in each grade change with changing 

seedbed density. The authors attempt to explain 

some of the possible reasons why the grade 

distributions for any one density may vary at 

different nurseries. 

DATA SOURCES AND MODELS 

Data from 15 studies showing the 

relationship between seedbed density and the 

proportion of loblolly or slash pine seed2 ings 

in each grade (1, 2, and cull) based on 

root-collar diameter were obtained from 10 

different sources in 9 states from Virginia to 

Texas (Table 11, These sources included two 

unpublished studies installed by the Auburn 

University Southern Forest Nursery baagaent 

Cooperative at one nursery in Alabama; data 

taken directly from two publications reporting 

the results of density studies in Florida and 

Louisiana (Burns and Brendemuehl 1971; Shoulders 

1961) ; additional data provided by the authors 

of three pub1 ished density studies in South 
Table 1. Available information on the density studies. 

No. Yr. of Date Density Density 

state Species Years Study Sow Date Thinned Lift Date N Classes Range 

Lobl 01 ly 

Lobl 01 ly 

Loblolly 

Lobl 01 ly 

Slash 

Lobl 01 ly 

Slash 

Lobl 01 ly 

Slash 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

May 10 --- Dec. 15 

April 27 --- Jan. 15 

? --- ? 

April 6 Hay Jan, 

? --- ? 

Mi d-Apr i 1 --- Dec. 6 

Mi d-Apr i 1 --- Dec. 6 

? ? ? 

? ?* ? 

April 22-24 Late May 1/30-2/25 

April 22-24 Late May 1130-2/25 

April 22-24 Late May 11'30-2/25 

Mid-April Early July Feb. 

Early April July Dec.-Jan. 

Early April July kc.-Jan. 

? --- Oct. 20-21 

F1 = 84,25,70 kg/ha N-P-K A Sown at different densities; actual plot densities used. 

F2 = 168,50,140 kg/ha N-P-K Sown at different densities; sowing density classes used. 

F3 = 335,100,280 kg/ha N-P-K Thinned; target density classes used. 

U1 = No undercutting Thinned; actual densities used. 

U2 = Undercut in July, Sept. Operational range of densities. 

Carolina, Mississippi and Texas (Harms and Langdon 

1977; Switzer and Nelson 1963; Nebgen and Meyer 

1986) ; three unpublished studies from Arkansas, 

Florida and Georgia; and data frm operational 

beds at a nursery in Virginia where there was a 

wide range of seedbed densities. In some 

instances, more than one species was tested or a 

second treatment such as fertil izer was included. 

In these cases, each set of data was taken 

separately. The infomation obtained from these 

studies was in varying degrees of completeness. 

Some were studies in which seeds were sown at 

different densities, while others were sown at a 

single density and thinned to different densities 

at various times af ter sowing able 1). Some 

data included the actual seedbed densities at time 

of lifting and measurement, while others reported 

only the target or sowing densities (Table 1). 

Curvil inear regressions were computed for 

each grade in each study, regressing the percent 

in a given grade on the seedbed density (Tables 2, 

3, and 4; Figure 1). Where possible, individual 

plot values were used in these regressions. 

Otherwise, the overall mean for each density 

reported was used. All curves for grade 1 were 

fitted to an exponential model of the form eeX, 

while grade 2 and cull models were of the 

quadratic f om. In general, models predicting 

either the percentage of grade 1 and cull 

seedlings had higher R-square values than models 

predicting the percentage of grade 2 seedlings. 
Table 2. Computed coefficients and R-square values for nonl inear 

regressions of grade 1 percent; (PI on density (X = number 

per square meter). Model : Y = Bg * e(-B1 * 

State Species 0 El a2 

AL- '83 Lob1 ol ly 97 .O 0.00864 0,75 

AL - '85 Lob1 01 ly 134.6 0,00348 0.92 

AR Lob1 01 ly 154-8 0,00544 0 -95 

FL Loblolly 324.9 0 .Of 004 0.92 

FL Slash 121.4 0 -00425 0 -97 

G A Lob1 01 ly 117.9 0 -00897 0.95 

G A Slash 72.6 0.00960 0.98 

LA Lob1 01 ly 147.1 0.00348 0 -89 

LA Slash 117.7 0.00254 0.70 

KS - Fl Lob1 01 ly 119.2 0.003 89 0.36 

MS - F2 Lob1 01 ly 132,l 0 -00374 0 -67 

MS - F3 Lob1 01 ly 87.7 0,000 92 0 -20 

SC Lob1 olly 126.9 0.00295 0 -87 

TX - U1 Lob1 01 ly 161.4 0,00482 0-39 

TX - U2 Loblol ly 459.5 0.01088 0.42 

V A Loblolly 91.3 0,00277 0.22 

Table 3. Computed coefficients and R-square values for nonl inear regressions 

of grade 2 percent (Y) on density (X = number per square meter), 

Model: Y = Bg + (B1 * X) + (B2 * x2). 

State Species 0 Bl B2 R~ 

Lobl 01 ly 

Lobl 01 ly 

L obl 01 ly 

Loblolly 

Slash 

Loblolly 

Slash 

Lobl 01 ly 

Slash 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Loblolly 

Lobl 01 ly 

Lobl 01 ly 

Lobl 01 ly 

Table 4. Computed coefficients and R-square values for nonlinear regressions 

of cull percent (Y) on density (X = number per square meter). 

Model: Y = Bg + (B1 *XI + (B2 *x2). 

State Species 0 B1 B2 ~2 

AL - "3 Loblolly 1.50 0.0229 0.000149 0.53 

AL-'85 Loblolly -0.98 0.0155 0,0000 80 0.95 

AR Loblolly -30,OO 0.2338 -0.000163 0.97 

n LO~LO~~~ 18.15-0.1543 o .a00362 o -90 

n Slash 4-09 0 .OO 97 0.000039 0.91 

G A Lob1 01 ly -22.93 0.2655 -0,000197 0.89 

GA Slash -1 5 .11 0.2532 -0.000139 0 -96 

LA Loblolly 3 -85 -0.0104 0.000166 0 -84 

LA Slash 5.00 -0.0216 0.000162 0 -86 

NS - F1 Lobl 01 ly 2 -67 0.0018 0,000083 0 -23 

MS - F2 Lob1 01 ly 8.30 -0.0603 0 ,000102 0.34 

M6 - F3 Lob1 01 ly 3.03 -0.0259 0.000048 0.20 

SC Loblolly -17,lO 0 .I364 -0.000066 0.74 

TX - Ul Loblolly 33.50 -0.1955 0.000315 0.16 

TX - U2 Loblolly 34.83 -0.2255 0.000416 0.24 

V A Loblolly -9.77 0,041 7 -0,000002 0.30 
RESULTS AND DISCUSSION 

Several of the density studies were thinned 

to the desired densities, rather than sown at 

different densities. Two studies were thinned as 

late as July. By this time, there may already 

have been competition or shading effects, which 

could infLuence response to lowered densities. 

In every study, increasing seedbed density 

led to a reduction in the proportion of grade 1 

seedlings and an increase in the cull percent. At 

the lower densities, the proportion of grade 2 

seed1 ings tended to increase with density, but 

generally levelled off or decreased in the higher 

density ranges. 

Many organizations manage for a seedbed 

density of 300 seedlings per square meter. Table 

5 shows that the seedlings produced at this 

density can vary widely in terms of their grade 

distributions, This variation may be explained by 

a number of factors which will be discussed later. 

While four of the 16 studies had greater than 50 

percent grade 1 seed1 ings at this density (300 per 

square meter), five others had less than 20 

percent grade 1. Table 5 also lists the density 

required to produce 300 plantable seedlings per 

square meter. While all or nearly all the 

seedlings were plantable at this density for 

several studies, it was impossible to get 300 

plantables at any density for three others. These 

results demonstrate that sowing at the same 

density will not produce the same results at every 

nursery and in every situation. 

Table 5. Predicted values for grade distributions at 300 and 200 seed1 ings per square 

meter, and density required to produce 300 and 200 plantable seedlings per square 

meter. 

Predicted Grades Density Required Predicted Grades Density Required 

at 300/d to produce 300 at 200/m2 to produce 200 

State Species Grade 1 Grade 2 Cull Plantables/m2 Grade 1 Grade 2 Cull Plantables~d 

AL - 83 Zoblolly 7 68 22 503~ 17 7 2 12 237 

AL-85 Loblolly 47 40 11 3 56 67 25 5 212 

AR Loblolly 30 47 2 6 ,-B 52 38 10 2 46 

n ~oblolly 16 81 4 318 44A 56A 2A 20 5A 

FL Slash 34 5 7 10 341 5 2 40 8 216 

G A Slash 4 4 7 48 ---B 11 57 3 0 ---C 

LA Loblolly 52 30 16 448 73 16 8 217 

LA S lash 5 5 28 13 377 7 1 19 7 214 

MS - F1 Loblolly 37 5 5 11 3 42 55 39 6 21 1 

MS - F2 Loblolly 43 56 0 300 62 3 6 0 200 

t-5-F3 Loblolly 67 3 4 0 300 7 3 2 7 0 200 

SC Loblolly 52 30 18 418 70 2 1 8 22 8 

TX-U1 Loblolly 38 55 3 309 62A 48A 7A 2 16A 

TX - U2 Loblolly 18 80 5 315 52A 40A 6A 217~ 

VA Loblolly 40 5 9 3 310 52A 56A 0A 200A 

------------------------------------------------------------------------------------------- 

Average 34 51 14 52 40 8 

A Outside the range studied. 

Impossible to produce 300 plantables/m?. 

Impossible to produce 200 plantables/&. 
Len~th of Growina Season 

On average, reducing seedbed density will 

increase the percentage of grade 1 seed1 ings while 

decreasing the production of culls. For these 

studies, when the density is reduced from 300 to 

200 per square meter, the percent of grade 1 

seed1 ings is increased by an average of 18 

percentage points and the cull percent is reduced 

front an average of 14 percent to 8 percent (Table 

5). When using expensive seed, reducing the cull 

percent can result in dramatic savings in seed 

costs (South 1986). Furthermore, increasing the 

percentage of grade 1 seed1 ings can increase 

future wood production (Caulf ield et al. 1987). 

While each study showed nearly the same type 

of response to density, the magnitude of the 

response was highly variable between studies. In 

some studies, the percentage of grade 1 seed1 ings 

dropped rapidly when density was raised above *e 

very lawest levels, with culls increasing 

correspondingly. In other studies, the response 

was not as dramatic, and the distributions were 

less sensitive to density. Seed source or family 

may affect response to density. Various cultural 

practices such as timing of sowing and lifting, 

fertility and soil management, undercutting, and 

irrigation can a1 so affect diameter distributions 

at different densities, 

The effects of sowing and lifting timing were 

demonstrated by the two Alabama studies conducted 

at the same nursery in two different years. The 

first year, seed1 ings were sown in May and 1 ifted 

in mid-December (Table I), and the percentage of 

grade 1 seedlings dropped rapidly as seedbed 

densities were increased above 100 per square 

meter, The second year, seed1 ings were sown in 

April and measured in mid-January. In this study, 

the proportion of grade 1 seedlings remained much 

higher at greater densities. Perry (1971) showed 

that loblolly pine seedlings increased 

significantly in weight from December to January 

and from January to February. McNabb (1985) 

demonstrated that slash pine seed1 ings can 

increase in diameter through the fall and winter, 

Furthermore, delaying sowing can result in a 

reduction in seedling diameter at the end of the 

season. Sawing just a week or two earlier in the 

spring can have a significant effect on seedling 

size by the end of the year because of the 

exponential nature of seed1 ing growth (van den 

Driessche 1969). 

Fertility 

Data from the Virginia nursery seem to 

contradict the importance of lifting or 

measurement timing. These seed1 ings were measured 

in October, yet show a relatively large proportion 

of grade 1 seedlings. This may be explained by 

fertility. This nursery is usually fertilized 

with a high rate of nitrogen (240 kgfha), which is 

about 50 percnt greater than most nurseries apply 

and may compensate somewhat for the reduced 

growing space and increased competition at higher 

densities. The fertility effect is demonstrated 

clearly by the Mississippi data, Seedlings grown 

at higher densities respond proportionately more 

to nitrogen fertilization than seedlings grown at 

lower densities (Fisher and Mexal 1984). With the 

highest rate of fertilizer, increasing density 

from 161 to 300 per square meter had a marginal 

effect on the proportion of seed1 ing grades. 

Pharis et ale (1964) also showed that diameter 

growth is markedly affected by the level of 

nitrogen supplied. 

Undercutting 

The effect of undercutting on the 

distribution of seed1 ing grades was demonstrated 

by the Texas studies, Seedlings which were 

undercut had fewer grade 1 seed1 ings. 

Undercutting and wrenching have been found to 

reduce root-collar diameter in loblolly (~iller et 

- al, 1985; Tanaka et al. 1976; Walstad et al. 1977) 

and radiata pine (Pinus radiata D. Don) seed1 ings 

(Rook 1971). 

Irrirrat ion 

Irrigation is another factor which can 

influence these curves. Unpublished data from the 

Auburn University Southern Forest Nursery 

Cooperative have shown that at a sandy nursery in 

Florida, irrigating in the fall can significantly 

increase root-collar diameter (by about 10 

per cent ) . Minko (1975) increased seed1 ing 

diameter by 20 percent or more by increasing 

irrigation by 12.7 mm per week in the early part 

of the growing season. 

SUMMARY AND CONCLUSIONS 

These studies, conducted at several different 

nurseries across the South, show that seedling 

grade distribution responds to seedbed density in 

a similar manner. That is, the proportion of 

grade 1 seedlings drops relatively sharply as 

density is increased, then levels off near zero. 

The grade 1 curve is typically in the emX form. 

The cull percent generally rises gradually with 

increasing density until the higher densities when 

it rises more sharply, The percent of grade 2 

seedlings usually increases through the lower 

densities, then levels off or decreases as culls 

begin to make up the greatest proportion of the 

seed1 ing population at the higher densities. 

The magnitude of these responses can be 

greatly affected by cultural practices such as 

fertilization, irrigation, and undercutting. 

Increased nitrogen fertilization and irrigation 

can to some extent offset the competitive effects 

of higher densities, while undercutting may reduce 

seedling diameter and thus decrease the proportion 

of seedlings in the higher grades. Waiting until 

the seedlings have become established and are 

interacting with each other to thin to desired 

densities may not have the same effect as sowing 

at lower densities, 
While many seedbed density studies have been 

conducted in southern nurseries, the imrestigators 

rarely report cultural practices such as sowing 

and lifting dates, soil type, fertilization and 

irrigation regimes, and other cultural practices 

which are 1 ikely to affect how seedling morphology 

responds to changing seedbed density, The intent 

of this paper was to not only demonstrate how 

seed1 ing grade responds to seedbed density but 

also to show that the actual distribution of 

grades at any one density will depend upon many 

factors. Our attempts to explain differences and 

similarities among these studies were hampered by 

a lack of information on how the seed1 ings were 

raised. More complete information on seedl ing 

culture in studies like this would be desirable so 

that research efforts may be more definitively 

compared. 

The authors thank all persons who have 

contributed data. We especially wish to thank 

George Switzer, Bill Hams, Russell Nebgen, Alan 

Webb, and Tom Dierauf for providing raw data from 

their density studies. We also thank John Mexal 

for his assistance with this paper. 

LITERATU RE CITED 

Boyer, James N.; South, David B. Loblolly pine 

seed1 ing morphology and production at 53 

southern forest nurseries. Tree planters' Notes 

(In press); 1987. 

Burns, Russel 1 M, ; Brendemuehl, R, H. Nursery bed 

density affects slash pine seedling grade and 

grade indicates field performance. Res. Pap. 

SE-77. Asheville, NC: U.S. Department of 

Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1971. 7 pp. 

Caulf ield, Jon P. ; South, David, B. ; Boyer, Jarnes 

N. Nursery seedbed der'sity is determined by 

short-term or long-term obj ectives. Southern 

Journal of Applied Forestry (~n Press); 1987. 

Fisher, T.T. ; Mexal, J.G. Nutrition management : a 

physiological basis for yield improvement. In: 

Duryea, Mary L.; Brown, Gregory I?. , eds. 

Seedling physiology and r e f o r e s t a t i o n success. 

Proceedings of the physiology working group, 

Society of Anrerican Foresters; 1983 October 

16-20; Portland, OR: 1984:271-299. 

Hams, William R, ; Langdon, 0. Gordon. 

Competition-density effects in a loblolly pine 

seedl ing stand. Res. Pap, SE-161, Asheville, 

NC: U.S. Department of Agriculture, Forest 

S e r v i c e , Southeastern Forest Experiment 

Station; 1977. 8 pp. 

Marx, D.H.; Cordell, C.E,; Kenney, D.S. [and 

others] * Commercial vegetative inoculum of 

Pisolithus tinctorius and inoculation 

techniques for develowent of ect mycorrhizae 

on bare-root tree seed1 ings. Forest Science 

Monograph 25; 1984. 101 pp. 

May, Jack T, Effect of density of stocking on the 

growth and development of long1 eaf , lob1 01 ly aad 

slash pine seedlings. Athens : University of 

Georgia; 1933, 52 pp. Thesis, 

McNabb, Kenneth Lee. The relationship of 

carbohydrate reserves to the quality of 

bare-root Pinus elliottii var, elliottii 

(~ngelm.1 seedlings produced in a northern 

Florida nursery, Gainesville: University of 

Florida, 1985. 154 pp, Dissertation. 

Miller, AWE,; Rose, R.W.; Ray, K.F. Root wrenching 

and top pruning effects on loblolly pine nursery 

seed1 ing development, In: Shoulders, Eugene, ed. 

Proceedings of the third biennial southern 

s i l v i c u l t u r a l research conference ; 1984 November 

7-8; Atlanta, GA: 1985 : 11-17. 

Minko, G. Effects of soil physical properties, 

irrigation, and fertilization on Pinus radiata 

seedling development in the Benalla nursery. In: 

Forestry technical papers ; Forests Commision; 

Victoria, Australia: 1975: 19-24. 

Nebgen, Russell J.; Meyer, Joann F. Seed bed 

density, undercutting, and lateral root pruning 

effects on loblolly seedling morphology, field 

survival, and growth. In: South, David B., ed, 

Proceedings of the international symposium on 

nursery management practices for the southern 

pines; 1985 August 4-9; Montgomery, AL: 

1986 : 136-147. [Available f ran Department of 

Research Information, Auburn University, AL] 

Perry, Thomas 0. Dormancy of trees in winter. 

Science 171:29-36; 1971. 

Pharis, Richard P,; Barnes, Robert L.; Naylor, 

Aubrey W. Effects of nitrogen level, calcium 

level and nitrogen source upon the growth and 

composition of Pinus taeda L. Physiologia 

Plantarum 17: 560-572; 1964. 

Rook, D.A. Effect of undercutting and wrenching on 

growth of Pinus radiata D. Don seed1 ings, 

Journal of Applied Ecology 8: 477-490 ; 197 1, 

Shoulders, Eugene. Effect of nursery bed density 

on loblolly and slash pine seedlings. Journal of 

Forestry 59:576-579; 1961. 

South, David B. Economics of seed efficiency. 

Journal of Forestry 84~32-35; 1986. 

South, David B. ; Mexal, John G. Growing the "best" 

seed1 ing for ref orestation success. Forestry 

Departmental Series No. 12. Auburn University, 

AL; Alabama Agricutural Experiment Station; 

1984. 11 pp. 

South, David B.; Boyer, James N.; Bosch, Leonard. 

Survival and growth of loblolly pine as 

influenced by seed1 ing grade : 13-year results. 

Southern Journal of Applied Forestry 9(2) : 76-81 ; 

1985. 
Switzer, G.L. ; Nelson, L.E. Effects of nursery 

fertility and density on seedling 

characteristics, yield, and field perf orsnance 

of loblolly pine (Pinus taeda L. 1, Soil Science 

Society of herica Proceedings 27(4) :461-464; 

1963, 

Tarmka, Yasuonti; Walstad, J.D. ; Borrecco, JOE. 

The effect of wrenching on morphology and f ield 

performance of hug1 as f ir and lob1 01 ly pine 

seed1 ings , Canadian Journal of Forest Research 

6:453-458; 1976. 

Wakeley, Philip C. Planting the southern pines, 

Agriculture bnograph 18. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1954. 233 

PP* 

Walstad, J.D.; Breland, J.H.; Mexal, J.G, 

Application of wrenching and lateral pruning in 

loblolly pine nurseries. Southern Forestry 

Research Center Technical Report 74-12. 

Weyerhaeuser Company; Hot Springs, AR: 1977. 

van den kiessche, R. Forest nursery handbook. 

Res, Note No. 48. Victoria, B. C. , Canada: 

British Columbia Forest Service; 1969. 44 pp. 
100 ALABAMA - LOBLOLLY - 1983 

Grade 1 

Grade 

Cull 

2 ---, - 

CAROLINA-LOBLOLLY 

I-- 

DENSITY ISEEDLINGS PER SQUARE METER] 

loo 4 MISSISSIPPI-LOBLOLLY (~1) 

MISSISSIPPI -LOBLOLLY 

0 180 200 300 400 500 600 700 

DENSITY I SEEDLllJGS PER SQUARE METER l 

Figure 1 .--Curvilinear regressions of percent in each grade on seedbed density for each study. 

196 
loo l TEXAS -LOBLOLLY I U 1 1 

100 TEXAS - LOBLOLLY I U 2 1 

.I----- "-, 

/'* 

*. 

W 40 P 

FLORIDA - LOBLOLLY 

80 -/Me---- --=\ 

ARKANSAS -LOBLOL W '"3 80 

GEORG lA - LOBLOLLY 

80 

GEORGIA-SLASH 

80 .r~/ 

LOUISIANA- SLASH 

80 

FLORIDA - SLASH 

80 

DENSITY ISEEDLINGS PER SQUARE METER l DENSITY ISEEDLINGS PER SQUARE METER 1 

Figure 1 ,--Continued, 
EFFECTS OF PvURSERY BED DEhSITY AiziD Fi,KTILIZA'I'IOl< Olu THE ElORPHOLOGY, 

NCTRIbhT STATUS, 1LLU KOOT GKOWTh 2OTEiUTlAL OF bhORTLLM PIhE SEEDLI~G& 

John C. Brissette and William C. Carlsodi 

Abstract.--The effects oi seedbed density and different levels of 

phosphorus nitrogen on the morphology and ~hysioiogy of shortleaf pine seedlings 

were studied under operational nursery conditions. Density and the amount of 

nitrogen applied affected diameter, tieight, and root volume, but the level 

of phosphorus in the soil did not. dased on these morphological measures that were 

obtained from 40 treatment combinations, 9 treatments (3 levels of density and 3 

levels of nitrogen) were selected for physiological evaluation. Among the 

selected treatments, nutrient concentrations were affected most by nitrogen 

application. Although the combined concentration of nitrogen in stems and 

needles was dependent on total nitrojien applied, the relationship was not 

linear. Phosphorus and potassium concentrations both declined with increasing 

total nitrogen. At 15O and 20°C, root grohth potential was related to density, 

root volume, and nitrogen application. The number of new roots increased with 

decreasing density and increasing root voleme. Though applied nitrogen had an 

affect on root growth potential, the relationship was not clearly defined. 

INTRODUCTION 

Shortleaf pine (Pinus echinata Mill.) is the 

most important species used for artificial 

regeneration on the Ouachita and Ozark hational 

Forests. Approximately 12 million seedlings are 

planted annually on about 17,000 acres of the two 

forests, The success of the program has been 

limited by poorer survival and slower initial 

,rowth than are generally obtained with the 

southern pines on other national forests 

throughout the Southern Kegion. Poor seedling 

;terformance may be related to: (1) the generally 

droughty soil conditions on many sites, (2) poor 

seedling handling and planting techniques, or (3) 

the quality of the seedlings produced for planting 

on these mountain sites. 

Seedling quality can be defined both in terns 

of morphology and physiology. The most widely 

recognized standards of morphological quality for 

couthern pine planting stock are those described 

fly kiakeley (1954), which specify that undamaged, 

c'isease-free shortleaf pine seedlings have a root 

collar diameter greater than 3.2 mm to be 

considered plantable. Recognizing the effect of 

the basal crook in shortleaf pine, Chapman (1948) 

-- 

- Paper presented at the Fourth biennial 

southern Silvicultural Research Lonkerence, 

htlanta, Georgia, l$ovenber 4-5, 1986. 

- Silviculturist, bSDA Forest Service, bouthern 

Forest txperinent Station, Pineville, LA 71360; 

bnd Tree Physiologist, lieyerhaeuser Company, tiot 

Lprings, AH. 71302. 

recommended a minimum diameter of 2.5 mm at 2.5 cm 

above the ground line. In general, such 

morphological criteria kor culling seedlings are 

substantiated by outplanting success. However, 

chere are enough exceptions that Wakeley (1949) 

recommended the development and adoption of 

physiological grades that better reflect survival 

and growth potential. tie suggested measuring such 

physiological attributes as nutrient content, 

stored food reserves, and seedling water status. 

Since then, much progress has been made in the 

pitysiological evaluations of planting stock, with 

root growth potential (KGP) receiving most the 

attention (Stone 1955, Stone and Jenkinson 1971, 

Burdett 1979a, Kitchie 1985). KGP is a measure of 

a seedling's readiness to produce new roots; 

relatively higher KGP indicates better seedling 

cjuality than lower KGP. 

Shortleaf pine has not received much 

attention by nursery researchers in the past. At 

rlost nurseries where it is grown, shortleaf pine 

is cultured much like loblolly pine (Y. taeda L.). 

iiowever, in an early study, tiuberman ( 1940) showed 

that shortleaf pine has a different growth pattern 

than loblolly pine. Therefore, it is possible 

that altering nursery culture for shortleaf pine 

would improve seedling quality and field 

iertormance. 'Lwo basic aspects ok bare-root 

seedling culture that greatly inkluence stock 

%uality are soil kertility and seedbed density 

(Switzer and &elson 1963). 

The purpose oi this study was to determine 

rhe ekfects of seedbed density and different 

levels ok phosphorus and nitrogen on the 
morphology and physiology of shortleaf pine 

seedlings growing in a nursery. 

YATERIALS AND METHODS 

Kurserv Design and Treatments 

Seedlings for this study were grown at 

Weyerhaeuser Company's Wagnolia Forest Regeneration 

Center in Columbia County, Arkansas, The nursery 

soil is classified as Ruston fine sandy loam. The 

study was laid out on eight beds, seven between 

two adjacent irrigation lines plus an adjoining 

bed. Because phosphorus (P) must be incorporated 

before the seedbeds are formed, and to conserve 

space, a split-split plot design was used. The 

major plots were two levels of P fertility on a 

60-m segment of a nursery bed. The subplots were 

five levels of seedbed density, and the sub-sub 

plots were tour levels ok nitrogen (h) fertilizer 

applied during the growing season as topdressings. 

The density subplots were 12 m long and each LY 

sub-subplot was 3 m. The study contained 40 

treatment combinations replicated 4 times for a 

total of 160 plots. 

The two levels of P were: (1) the base level 

in the soil when sampled in December 1984 

(approximately 54 p/m by the Strong Bray 

extraction method) and (2) enough added fertilizer 

to theoretically yield 150 percent of level 1 

(approximately 81 p/m). For level 2, 300 kg/ha of 

0-46-0 fertilizer was incorporated in two equal 

applications 1 and 2 weeks before sowing. 

Seeds for the study were from the medium-size 

fraction of a bulked seed lot collected at the 

USDA Forest Service's Ouachita-Ozark Seed Orchard 

near Mt. Ida, Arkansas. The seeds were sown with 

a Weyerhaeuser-designed precision vacuum sower on 

April 16, 1985. The five target densities of 

living seedlings were: (1) 160/m2, (2) 230/n12, (3) 

295!rn2, (4) 360/m2, and (5) 430/m2. 

Topdressing with h began on May 28, 1985, 6 

weeks after sowing, Ammonium sulphate (21 percent 

bi and 23 percent sulfur) was applied with a Gandyb 

fertilizer spreader calibrated to apply 11 and 

17 kg N/ha. It was pulled over each bed two times 

and was opened or closed over each plot, on one or 

borh passes, to apply the specikied rate of 

fertilizer, Application dates after May 26 were 

June 13, June 25, July 11, and July 26. Total h 

applied for the four levels was: (1) 55 kg/ha, (2) 

85 kg;ha, (3) 118 kgjha, and (4) 170 kg/ha. A11 

other nursery cultural practices were operational, 

based on the nursery manager's best judgement. Un 

August 21, the seedlings were undercut 

(horizontally root pruned) at 15 cr to kelp 

control shoot growth. The actual density of each 

plot was determined on September 6. They were 

undercut again on hovember 21. 

Actual seedbed densities in this study were 

lower than the target densiries because 

germination was poorer than expected, Average 

density for each level in the study was: 141ln1~, * 

218/m2, 269/m2, 296/n2, and 296/n2, hntc that the 

two highest levels were the same. Although the 

highest density was well below the sowing target, 

it was higher than the operational level (270/t~~) 

recommended by Chapman (1948) but much lower than 

the density (540-590/m2) suggested as a maximum by 

Wakeley (1954). 

Seedling Measurements and Analyses 

On December 10, 1985, an eight-seedling 

transect, representing one seedling from each 

drill row, was carefully hand-lifted from within 

the center 2 m of each plot. These seedlings were 

measured for diameter, height, and root volume. 

Root volume was deternined by the displacement 

method (Burdett 1979b). The effects oi the 

nursery treatments on each seedling attribute were 

evaluated separately using analysis of variance. 

For factors with significant differences, 

orthogonal polynomial conparisons were made to 

evaluate the effects ot the levels within that 

factor (iiiize and Schultz 1985). 

based on these results, nine treatment 

combinations representing the extremes in 

seedling morphologies found in the study, were 

selected for further laboratory and field testing. 

The selected treatments included three levels of 

density and three levels or h application. The 

actual densities varied some with plot but were 

the low, middle, and high sowing rates and 

averaged 135, 220, and 291 seedlings/rn2, 

respectively. The selected N levels were the 

first, third, and highest levels, or low, 55; 

mediuw, 110; and high, 170 kg N/ha, respectively. 

Eight to ten seedling shoots (stems and 

needles) from each plot were clipped on August 6 

and December 10 for later chemical analysis. 

These shoots were pooled for each plot, then 

dried, ground, and analyzed for h, P, and 

potassium (K) concentration. The samples were 

digested in sulfuric acid with copper sulfate 

added as a catalyst. hitrogen concentration was 

determined with an ammonia-specific electrode 

(Powers and others 1981), P was determined 

coLornetrically (John 1970), and K by atomic 

absorption spectrophotometry. 

On February LO, 1986, about 300 seedlinbs 

trom each of the 9 selected treatments were 

carekully hand-lifted for physiological testing. 

From those lifted, seedlings were selected to spar 

the range in morphologies within a treatment; 

consequently, each nursery replication was not 

represented equally. Twenty seedlings trom eacn 

treatment were randomly assigned to one of three 

KGP temperatures, lo0, 15', or 2U°C, in the systen 

descr~bed by Wsldren and others (14b5). The rest 

of the seedlings were used in additlorial tests, 

which will be reported on in another article. 

The seedlings were cold-stored until the kGP 

tests began on April Zb, 1486. The root volume 

and height of each seedling were measured; then 

the seedlings were potted in sand, and no 

nutrients were added during the 28-day test 

period. At the end of trw test, &GP was measured 

as the nunoer oji: new roots greater than 1 cri in 

length. 
The effects of nutrition and seedbed 

density on the August and December content of h, 

P, and K in shoots were determined for the selected 

treatments for each element using analysis of 

variance. For treatment factors that resulted in 

significant differences, orthogonal polynomials 

were used to evaluate trends among levels of that 

factor. For evaluating the effect of density, 

actual plot densities were used in the 

polynomials. 

The effects of seedbed density and applied N 

on RGP of the nine selected treatments were tested 

using multiple linear regression for each 

temperature regime. The regression models were 

developed using actual plot densities, amount of h 

applied, density squared, N squared, and density x 

N as the independent variables, and the number of 

new roots as the dependent variable. Similar 

models were developed using seedling root volume, 

height, their squared values, and the interaction 

term as independent variables to examine the 

effect of seedling morphology on KGP. The 

significant factors were then combined into one 

multiple linear regression model for each 

temperature to determine how much of the variation 

in RGP could be explained by the experimental 

treatments. 

RESULTS AND DISCUSSION 

Seedling Morphology 

Among the December-lifted seedlings, 

diameter, height, and root volume were all 

significantly affected by seedbed density and N, 

but not by P (table 1). Phosphorus was probably 

not important because a sufficient base level 

existed at the start of the study. There were no 

significant interactions among treatment factors 

for any of the characteristics measured. Overall 

means for the study were diameter, 4.0 mm; height, 

186 mm; and root volume, 2.3 cm3. Within seedbed 

density and nitrogen, orthogonal polynomial 

comparisons were used to examine the relationships 

among levels of those treatment factors. Highly 

significant, linear relationships were obtained 

between density and each of the characteristics 

measured. Seedling diameter and root volume 

decreased with increasing density, while height 

increased with density. The relationship between 

density and root volume was much stronger than the 

relationship between density and diameter. 

Diameter and root volume also had highly 

significant linear relationships with total N 

applied, increasing as N increased. For height, 

however, there was a significant second degree 

regression with N. Seedlings grown under the 

third level of N (110 kg/ha) were taller than 

those grown with more (170 kg/ha) or less (55 or 

85 kg/ha) N. Although we did not determine the 

reason for that response, it may have been a 

result of the reduction in soil pH caused by the 

ammonium sulfate used as the source of h. At the 

highest fertilizer rate, about 186 kg/ha of sulfur 

was applied along with the 170 kg/ha of h. It may 

also have been a result of an increase in the salt 

level in the soil, again caused by the f'ertilizer 

used. 

Shoot Nutrient Concentration 

The nutrient concentrations in the stems and 

needles of seedlings from the selected treatments 

sampled in August and December were affected by 

total N applied and, in the case of K 

concentration in December, by seedbed density 

(table 2). Among the August-sampled seedlings, 

the only significant relationship was between 

applied N and N concentration, with the 

concentration of N in the stem and foliage 

increasing linearly with increasing N level. The 

August sample was taken 11 days after the last 

application of h in the experiment. Nitrogen 

concentration, therefore, was probably at a level 

higher than during the rest of the growing season. 

It did, in fact, drop across all levels of both 

treatment factors when sampled again in December. 

However, by December, N concentration had dropped 

much more in seedlings from the medium level of h 

application (110 kg/ha). A significant second 

degree regression resulted with seedlings from 

both the low N (55 kg/ha) and high N (170 kg/ha) 

treatments having higher iq concentrations than 

those from the medium N treatment. This pattern 

is opposite of that for height, i. e., seedlings 

with the lowest N concentration in December were 

the tallest. Therefore, although the N 

concentration was lower in the tallest seedlings, 

total Iv content may not have been. 

As the amount of h fertilizer was increased, 

December-sampled seedlings had a significant 

linear decline in P concentration (table 2). The 

concentration of K in the stems and foliage of 

December-sampled seedlings showed a similar 

significant linear decline with increasing N 

fertilization. Moreover, there was a significant 

linear increase in K concentration with increasing 

seedbed density. Therefore, the seedlings with 

the highest concentration of K were from the high 

density, low N treatment, and those with the 

lowest K concentration were from the low density, 

high N treatment. 

Boyer and South (1985) reported nutrient 

concentrations of loblolly pine seedlings sampled 

from 21 nurseries between hovember and January. 

They analyzed foliage and stems separately. 

Although the species and sample techniques 

differed, a comparison between our results and 

their foliage values is informative. They 

reported foliar N concentrations of between 9.2 

and 22.4 glkg, with a median value of 16.4. Our 

overall December N concentration was 14.2 g/kg. 

The P concentration in their study was between 1.2 

and 3.0 g/kg, with a median of 2.1. In our study, 

P averaged 1.6 g/kg. For K, they reported values 

of between 8.2 and 14.7 g/kg, with a median 

concentration of 11.2. Our seedlings had marked13 

less K, with an average of 5.6 g/kg and a maximum 

of only 6.4 for seedlings from the high density, 

low N treatment. Boyer and South (1985) gave no 

indication of what concentration may represent a 

deficiency of a particular nutrient, or how the 

nutrient levels related to seedling quality. 

Fowells and Krauss (1959) studied the 

effects of applied N and P on nutrient uptake of 

lobloily and Virglnla plne (y. vlrglnlana ivlill.) 
Table 1.--The effects of different levels or phosphorus, seedbed density, and 

nitrogen, on the morphology of bare-root shortleaf pine seedlings 

Treatment 

factor Characteristic 

and level Root collar diameter Height Koot volume 

Phosphorus (1,3)a 

Density (4,24) 

Nitrogen (3,90) 

4.0 

4.1 

b/ .09 nsOverall means 4.0 186 2.3 

- a/ Lumbers in parentheses are degrees ot i reedom for each factor in the 

split-split plot design with 4 replications. 

- b/ F statistic and: ns=not significant, * = P < 0.05 , *** = P <U.001. 

- '/ Degree of orthogonal polynomial, F statistic, and significance of the 

regression anlong levels. 

grown in sand culture. Their digestion methods 

were similar to ours, but they also ran separate 

analyses tor needles and stems. hevertheless, 

their results were similar to ours in that foliar 

IS concentrations increased with N fertilization, 

while the concentration of K declined. Hased on 

their sand culture experiments and information 

from naturally grown trees, they concluded that 

lohlolly and Virginia pines do not differ in 

their requirements for h and P. Furthernore, 

they concluded that concentrations of 17 to 23 

g/kg of !d and 1.4 to 1.6 g/kg of P in the foliage 

in December indicates satistactory nutrition. 

Based on these results, it appears likely that our 

shortleak pine seedlings received at least 

marginally sufficient nutrition in all our 

selected treatment combinations. 

Koot Growth Potential 

in thls study, KGP was evaluated at three 

root zone temperatures -- lo0, 15", and 2U°C 

(table 3). At 10°C, the number of new roots 

ranged from an average of 0.2 for the high 

density, high N treatment to 1.0 for two 

treatments, low density, high N and medium 

density, low h. The overall mean of the 180 

seedlings tested at this temperature was 0.6 new 

roots. The coefficient of variation (CV) was very 

high at 162 percent. The multiple linear 

regression did not show a significant (P(0.05) 

relationship between the number of new roots and 

either density or level of applied ik. A similar 

regression with root volume and height also did 

not show a significant (P(0.05) relationship 

between KGP and either morphological 

characteristic. At lif°C, KGP could not be related 

to nursery treatment. However, Carlson (1986) was 

not able to sttow significant differences among 

differences among half-sib families of loblolly 

pine at lU°C when using a similar experimental 

design. If the design was not sensitive enough to 

aetect genetic aikferences, it probably coulo not 

differences due to cultural treatment either, 
iabie 2.--xugust and brcember nutrl~nt concentrations in the steris and neeales 

or stiortlear pine seecilings grown utder dirferent rehlmes or seedbed denssty 

and L\ fertilization 

bample month/nutrrcnt 

'frea tment riUgUS t !lecer,be r 

iactor 

and level :is: P: K t. : k : x 

tensity ( Z,4)a 

135 17.5 1.4 1~1.5 14 ."1 1.7 14.3 

220 17.4 1.3 9.b 13.7 1 .G 5.4 

29 7 1.4 9.7 14.1 l .b 5.9 

17*'1 .ib ns .73 ns- 1.14 n., 1.45 ns .A1 ns 1 :lC.82*~-/ 

Overall cleans 17.5 1.3 10.1, 14.~ 1 .b 5.b 

- iiuntbers in parentheses are degrees or reedo om tor each *actor in rhe 

split-split plot aesibn hith 4 replica-ions. 

- " F statistic and: ns=not significant, * = P < 0.~5, ** = 1. < 11.01, 

*** = P < 0.b01. 

- C/ Degree oi orthogonal polynomial, Y sta: istic, and signiticance of the 

regression among levels. 

The value in using 10°C was in determining the 

threshold temperature for an kGP response in 

shortleak pine. 

At a root zone temperature of 15"C, there 

was a significant (P<C.Ol) but weak regression (r2 

= ,082) between the number ok new roots and 

density, total l* applied, and the lr,teraction 

between density and l-d (fig. 1). The regression 

was Y = 3.54806 + .0374X1 - .10935X2 - .00045X3, 

&ere Y = nu~ber of new roots >1 cni long, X1 = 

density, X2 = total tv applled, and X3 = aensity x 

total he RGE rangea fro= a low average of 4 new 

roots in the medium density, high "V treatment to 

12.8 in the low density, high r~ treatment (table 

3). The overall mean of the 180 seedlings tested 

was 6.0 new roots, with a CV ok 109 percent. 

The significant interaction at this 

temperature was largely a result of the high mean 

LEGP for the low density, high i'u treatment. In 

that treatment one seedling had 49 new roots, 

twice as many as any other seedling in the 

treatment. kith that seedling removed fron the 

data set, the regression and the interaction were 

still signikicant (P(0.05). With respect to 

density, KGP at 15OC generally increased kith 

decreasi~lg derisity at high levels oi: applied ik, 

but was less atfcctea as the amount ot 1. was 

reduced. However, at high density, hihb A 

resulted in the poorest predicted KGP, 

when tt-ie number or new roots was examined in 

relatson to seedling root volume and herght, a 

yosltsve low linear relationship (rZ = .1L7) wlth 

root volume was iound. The regression was Y = 

1.79541 + .75053X, where Y = number or new roots 

and X = root volun,e. 'ihe number or new roots was 

not related to height. Although the regression 

between KGP and root volume accounted for only 

12.7 percent of the variation, it was highly 

significant (P(0.001). 
RGP AT 15 DEGREES G 

Figure 1.--Actual (+) and predicted (response surface) number of new roots 

after 28 days at 15OC for shortleaf pine seedlings grown at three 

densities and fertilized at three levels of nitrogen. 

Because both root volume and RGP were 

strongly related to density, and to some degree to 

N, the results of the two regressions are not 

additive. However, when root volume was added to 

the density-nitrogen model, a highly significant 

(P<.001) multiple regression resulted that 

explained 17.1 percent of the total variation of 

RGP, That regression model was Y = 8.54393 + 

*69618X1 + *04604X2 + .09528X3 - .00041X4, where Y 

= number of new roots, X1 = root volume, X2 = 

density, X3 = total N, and X4 = density x total N. 

At ZO°C, a significant (P<0.001) regression 

RGP = ,155) resulted among RGP and density, total 

N, (total N12, and the density x N interaction (fig. 

2). The regression was Y = 12.33914 + .06726X1 - .28012X2 + .00188X3 - .00047X4, where Y = number 

of new roots, XI = density, X2 = total N, X3 = 

(total N)Z, and Xq = density x total N. Among the 

treatments, RGP averaged from 3.0 for the high 

density, medium M treatment to 17.7 for the low 

density, high N treatment (table 3). The best 

treatment at 20°C was also the best at 15OC. The 

overall mean of the 180 seedlings was 11.7 new 

roots and the CV was 84 percent, As at 15"C, 

there was a significant (P<0.001), positive linear 

relationship (r2 = .073) between the number of new 

roots and root volume. At 20°C, regression was Y 

= 6.69326 + .87163X, where Y = number of new roots 

and X = root volume. 

When root volume was added to the 

density-nitrogen multiple linear regression 

model, a highly significant (P<.OUl) relationship 

was found. The model, which explained 21.1 

percent of the variation in RGP at 20°C, was 

Y = 4.07003 + .85718X1 + .U7997X2 - .25077X3 + 

*00167X4 - .0046X5, where Y = number of new roots, 

X1 = root volume, X2 = density, X3 = total N, X4 = 

(total N)~, and X5 = density x total N. 

One interesting result at this temperature 

was the quadratic relationship between RGP and N 

fertilization. It shows the same recurring 

pattern among the levels of N as does seedling 

height (table 1) and December concentration of h 

in the stems arid needles (table 2). That is, ~~Cen 

compared across all densities, the medium level of 
Table ;.--'lhe average number of: new roots produceo 

by density and nitrogen-treatrient after 28 days 

at three root-zone tenperatures 

ioot zone temperature (OC) 

Treatment : 1L : 15 : LO ---- .LO. riew roots > 1 cr;------ 

Low densit) 

low 11 ii . b 4.4 b.3 

nediur? :L .4 5 .4 5.4 

hikh L4 1 .C !2-8 17.7 

hediun denslty 

low 1~ 1.0 b .6 il,8 

nediurr i., . i 4. 1 14.4 

hihh LY .4 4.b 14.7 

tiigh trnsity 

Loa L\ .5 6.2 

r#~e~cium i. i ., 5.1 

high t\i .Z 4.4 

Overall means . G 6.0 11.7 

L, used in thls study (110 kg/ha) resulted in the 

tallest seedlings but those with the lowest N 

concentration in their sttoots and with the lowest 

KGP at 20°C. liowever, although the regression 

resulted in a very strong quadratic relationship, 

the actual data for the medium level of h are not 

consistent with the predicted trend (fig.2). The 

two lowest values of kGP at 20°C came from the 

nedium L\ treatment at the extreme densities, but 

KGP from the nedium itl treatment at the niediunl 

density was among the best (table 3). 

Cork CLU S I Ot1 S 

beedbed density and h fertilization have 

significant impacts on the morphological and 

physiological quality ot shortleak pine seedlings. 

Within the levels of the treatment kactors used ir 

this study, diameter, root volume, height, nutriert 

status, and kGP were all affected by either density 

or the amount of h applied. The morphological 

attributes and KGP were affected by both, while 

nutrient status was determined primarily by the 

level of applied &. 

New root initiation and elongation varied with 

root zone temperature. At new root growth was not 

related to either nursery treatments or seedling 

morphology. But at 15O and 20"C, kGP was related to 

both nursery treatments and seedling root volume. 

The relationship among density, root volume, and kGP 

is gerterallp that lower density results in larger 

root volumes and higher KGP. The results also 

indicate that 13 fertilization in the nursery has an 

importar~t impact on KGP. However, the data do not 

clearly elucidate the nature of the relationship 

between h and RGP. The use of half-sib family 

material, car some other nethod of reducing the hipn 

variability ir KGP, would markedly inprove the 

chances of explaining the relationships between 

nursery cul'crel practices end PGP, The data do 

show that ir,creasing the amount of applied iv can 

increase root volume and thus compensate somewhat 

tor increasink density, 

several aspects or this study are still 

ongoing, and those results are needed to ~ake 

recommendations aboi:t target seedling 

specikicatiuns and the nursery practices needed tc 

grow ttiem. tiowever, these prelitiinary results 

suggest tkat seedbed densitres well below the 

maxirium used in this study will provide the 

~orphological and physiological attributes needed 

tor early root growth and establishment after out 

planting, Furtl-ier~ore, a lob^ level of applied k 

may be surficient it the loker densities are used, 

ACKL,O\.~I,CL~G~ ,hlITS : he t bank iJ . Andries, J , 

Anthony, 6. bower, J. hiser, J. riclrilvray, hi. 

Smith, and C. Stangle for assistance with this 

research and k. k. Plyler tor providing 

assistance during culture or the seedlings. 

aoyer, James I.,.; South, bavld b. f,utrient content 

of nursery-grown loblolly pine seedlings. 

Circular Lb2. Auburn, AL: Alabama hkricultural 

hxperlment Statxon; 1485. 27 p. 

r~urdett, A. r%. iVe+d ~etttods tor measuring root 

growth capacity: their value in assessing 

lodgepole pine stock quality. Canadian Journal 

of Forest Kesearch. 4:63-67; 1379a. 

Burdett, A. 14. A nondestructive method for 

measuring the volume of intact plant parts. 

Canadian Journal ot Forest k:esearch, 43:120-122; 

1979b. 

Carlson, k. C. hoot syste~ considerations in the 

quality st loblolly pine seedlings. Southern 

Journal of Applied Forestry. 10(2):87-92; 

Chapman, A. G. Survival and growth of various 

grades of shortleaf pine planting stock. Iowa 

State College Journal of Science, 22:323-331; 

1948. 

Powells, Barry A.; Krauss, kobert W. The 

inorganic nutrition of loblolly pine and 

Virginia pine with speclal reference to nitrogen 

and phosphorus. Forest Science. 5(1):95-112; 

1959. 

tiuberman, M. A. hormal growth and development of 

southern pine seedlings in the nursery, 

bcology. 21(3):323-334; 1940, 

John, tvi. K. Colorimetric determination of 

phosphorus in soil and plant materials with 

absorbic acid. Soil bcience. 109:214--220; 

1970. 

Mize, Carl W.; Schultz, Richard C. Comparing 

treatment means correctly and appropriately. 

Canadian Journal of Forest Kesearch. 

15:1142-1148; 1985. 

Powers, R. F .; Van Gunt, D. L.; Townsend, K. F, 

Anmmonia electrode analysis of nitrogen in 

micrnKjeldahl digest of forest ve~etat io~, 

Communications in boil Science and Plant 

Analysis. 12:lY-30; 1981. 
Ritchie, G.A. Root growth potential: principles, 

procedures, and predictive ability, In: Duryea, 

Mary L., ed. Proceedings, evaluating seedling 

quality: principles, procedures, and predictive 

abilities of major tests; 1984 October 16-18; 

Corvallis, OR, Corvallis, OR: Forest Research 

Laboratory, Oregon State University; 1985: 

93-105, 

Stone, E. C. Poor survival and the physiological 

condition of planting stock. Forest Science. 

1:90-94; 1955. 

Stone, E.; Jenkinson, J. L, Physiological grading 

of ponderosa pine nursery stock. Journal of 

Forestry. 69:31-33; 1971. 

Switzcr, G. t.; :wison, L. b. Effects of nursery 

fertility and density an seedling 

characteristics, yield, and field perfornance of 

ZoSlolZy pine (Pinus -- taeda L.). Soil Science 

Socxety of America Proceedings. 273461-464: 

1963. 

Wakeley, Phillip C, PhysioJogical grades to 

southern pine nursery stock. In: Proceedings, 

1948 Society of American Foresters Annual 

Fleeting; 1949:311-322. 

Wakeley, Phillip C. Planting the southern pines. 

Agric. Itlonograph 18. kashington, DC: U.S. 

Department of Agriculture; 1954. 233 p, 

WalCren, b. W.; kicK~nnis, M. K.; Carlson, k. C. A 

soil temperature control system kor plant 

research, Canadian Journal of Forest Research. 

15:472-474; 1985. 

RGP RT 28 DEGREES C 

Figure ?.--Actual (+) and predicted (response surtace) number of new roots after 

28 days at 20°C for shortleaf pine seedlings grown at three densities 

and fertilized at three levels of nitrogen. 
RELATIONSHIPS OF MORPHOLOGICAL ROOT AND SHOOT 

CHARACTERISTICS TO THE PERF0 CE OF OUTPUNTED BAREROOT AND 

1 / CONTAINERIZED SEEDLINGS OF LOBLOLLY PINE2 / Jean A. Wilder-Ayers and John R. ToliverAbstract.--Morphological root and shoot characteristics 

were measured on 20 half-sib families of bareroot and 

containerized loblolly pine (Pinus taeda L.) seedlings 9 months 

after germination. Bareroot seedlings were grown in nursery 

beds; containerized seedlings in a greenhouse. Ten seedlings 

from each family were chosen at random for measurement from each 

of five replications in both the nursery and greenhouse. Other 

seedlings were outplanted in the field. Simple linear 

correlations between root and shoot characteristics and 

first-year field performance of outplanted seedlings were 

calculated. Bareroot seedling shoot and root characteristics 

were generally positively correlated with first-year height but 

negatively correlated with height growth and survival. Only 

three characteristics of the containerized seedlings were 

significantly correlated with field performance of the 

outplanted trees, probably as a result of the uniformity of the 

containerized seedlings. Bareroot seedlings exhibited no 

significant family variation in height, height growth, or 

survival. In contrast, family variation among containerized 

seedlings was highly significant for first-year height and 

height growth. In this study, the containerized seedling 

progeny test did not reflect the results of the bareroot progeny 

test. 

INTRODUCTION 

Morphological seedling characteristics have 

been examined since the early 1920's to assess 

seedling quality and field performance (Wakeley 

1954). Characteristics of bareroot seedlings 

grown in nursery beds c3n differ from those of 

containerized seedlings grown in greenhouses. 

Consequently, morphological characteristics used 

to predict field pe--formance of outplanted 

seedlings may differ with the method of seedling 

production. 

The use of containerized seedlings has 

increased and is now a viable alternative to the 

use of bareroot stock. Although containerized 

stock may shorten the time span for growing 

seedlings, tree improvement researchers have not 

confirmed that the growth of containerized 

seedlings is equal or superior to that of 

bareroot seedlings grown in nursery beds 

(Kellison and Lea 1983). Both types of planting 

stock have advantages. 

The primary advantages of bareroot stock 

are its relatively low cost of production and 

ease of handling and transport. Nursery-grown 

seedlings also require less technical knowledge 

and daily attention and are less conducive to 

disease and nutritional imbalances than 

containerized seedlings grown in a greenhouse 

(Barnett 1978). 

I/ Paper presented at the Southern 

~ilvicultural Research Conference, Atlanta, GA, 

Nov. 4-6, 1986. 

- 21 Former Research Assistant and Associate 

Professor, School of Forestry, Wildlife, and 

Fisheries, Louisiana Agricultural Experiment 

Station, LSU Agricultural Center, Baton Rouge, 

LA 70803. 

On the other hand, containerized seedlings 

have several advantages. The most important is 

increased seedling uniformity. With proper 

management, raising seedlings in containers ran 

bypass problems encountered in nursery beds such 

as variations in germination and soil texture, 

low spots in the nursefy beds, and problems with 

weeds which may cause a lack of uniformity (van 

Bui j tenen and Lowe 1982). Containerized 

seedlings can survive and grow better than 
nursery stock despite the fact that they are 

often younger at outphanting (Barnett 1975). 

Root systems of the containerized seedlings 

remain intact, whereas bareroot seedlings need 

several months to regenerate roots lost during 

lifting and pruning (Barnett 1978). 

Large investments in planting both types of 

stock support the necessity for research on root 

form (Tinus 1978). Stein et al. (1975) stated 

that the effect of planting methods (bareroot or 

containerized) on subsequent seedling root 

systems, survival, and growth is an important 

aspect of reforestation that has not been 

completely evaluated. According to Leaf et al. 

(1978), the ability to establish healthy root 

systems is crucial for successful outplanting. 

Therefore, root mass is critical to seedling 

field performance (Duryea and Landis 1984). 

This research was a part of a larger study 

designed to evaluate the extent of genetic 

variation among root systems of bareroot and 

containerized loblolly pine seedlings 

(Wilder-Ayers 1986). In this paper, 

morphological root and shoot characteristics of 

bareroot and containerized seedlings were 

compared to assess their effects on survival and 

growth one year after outplanting. Another 

objective of this study was to determine if a 

containerized progeny test would be reflective 

of family performance when the same progeny were 

outplanted as bareroot seedlings.. 

METHODS 

Seed from 20 open-pollinated loblolly pine 

(Pinus taeda L.) families were provided by the 

Western Gulf Forest Tree Improvement 

Cooperative. The seedlings were grown at 

Louisiana Srtate University (LSU) in Baton Rouge. 

One-half of the seed were sown in nursery beds 

in April 1984 and grown as bareroot seedlings. 

The remaining seed were planted in June and 

grown in Styroblock-8 containers in a greenhouse 

for 9 months. The plot layout for each method 

of seedling production was a randomized block 

design, with 5 blocks, and 20 families within 

each block. 

In January 1985, 10 seedlings from each 

family in each replication were randomly 

selected for root and shoot measurements. These 

seedlings were carefully lifted from the nursery 

bed or extracted from their containers. 

Variables examined included taproot length, 

number of major lateral roots, average length of 

the five longest lateral roots, root forking, 

root collar diameter, shoot length, and root and 

shoot volumes (Wilder-Ayers 1986). A major 

lateral root was defined as one with a diameter 

of 1 mn or more; however, on some seedlings all 

lateral roots were smaller than 1 m, thus major 

lateral roots became a subjective 

classification. The displacement method as 

described by Burdett (1979) was used to measure 

volumes. After taking the initial measurements, 

taproots and laterals of the bareroot seedlings 

were pruned to 20 and 5 em, respectively and 

additional measurements were taken. 

The remaining seedlings were outplanted at 

Lee Memorial Forest in Washington Parish, 

Louisiana. The bareroot seedlings were 

root-pruned and planted in late January 1985, 

and the containerized seedlings were planted in 

mid-March. The soil was classified as a Ruston 

fine sandy loam (USDA Soil Conservation Service 

1970). The plantation design consisted of a 

split-split-plot treatment arrangement in a 

randomized block. Twenty blocks were split by 

seedling type (bareroot and containerized) and 

five seedlings per Emily were planted in rows 

within each type. 

Initial height of the seedlings was 

measured after outplanting. Seedling survival 

was recorded in May 1985. Weight was measured 

again in November 1985 to evaluate first-year 

growth, and survival was determined. 

Correlations between seedling root and shoot 

characteristics and variables measured in the 

field were calculated to examine relationships 

between seedling characteristics and the first 

year's growth and survival of seedlings. 

RESULTS AND DISCUSSION 

All characteristics of the bareroot 

seedlings were significantly greater (p 5 0.01) 

than those of the containerized seedlings with 

the exception of the number of laterals (Tables 

1 and 2). Because the differences in means 

between the two methods of seedling production 

were so large, subsequent analyses of the two 

seedling production types were conducted 

separately. 

Performance of Bareroot Seedlings 

All bareroot seedling shoot characteristics 

were positively correlated with first-year 

height growth and survival able 3). The same 

general trends were true of the root 

characteristics. This indicates that the larger 

the seedling at planting time, the taller it was 

at the end of the first growing season. 

However, survival and height growth decreased 

when larger seedlings were planted. Normally, 

this would not be true unless the shoot-root 

ratio was too large which we believe to be the 

major cause of poor survival (39 percent) and 

growth in this study. The shoot-root volume 

ratio of the bareroot seedling was 4.28:l (Table 

1) before pruning and 7: 1 after the roots were 

pruned to operational planting size. Wakeley 

(1954) stated that a Grade 1 plantable seedling 

should have a shoot-root ratio no greater than 

2.5: 1. Seedlings with larger ratios such as 

those in this study usually do not perform well 

in the field. In order to minimizing biasing 

normal development of the seedlings, no top or 

root pruning was performed in the nursery bed, 

so the only means of slowing growth was by 

withholding water. However, rainfall in Baton 

Rouge was sufficient to allow optimal growth and 

the seedlings grew to a much larger size than 
Table 1. Comparison of the means of characteristics measured on 

loblolly pine seedlings grown under two methods of seedling 

production (Wilder-Ayers 1986). 

Production method 

Seedling characteristic Bareroot Containerized 

Shoot 

Shoot length (em) 

Shoot volume (ml) 

Total shoot-root vol. ratio 4.28 .a .k 1. 9g1 

Shoot-root vol. ratio (pruned) 7.01 - - 

Root 

Root collar diameter (cm) 0.63 *it 0.34 

Total taproot length (cm) 24.93 .A .a 14.36 

Pruned taproot length (cm) 16.98 - - Number major lateral roots 16.07 k" 21.61 

Average lateral length (cm) 31.50 RJ~ 15.28 

Total root volume (ml) 6.72 "A 2.31 

Pruned root volume (ml) 3.76 - - 

""Means are significantly different between bareroot and 

containerized seedlings (p 5 0.01). 

'containerized seedling root systems were not pruned. 

Table 2. Comparison of means of characteristics measured on 

bareroot and containerized loblolly pine seedlings after one year in the field. 

Characteristics Bareroot Containerized 

~ei~ht' at outplanting (cm) 29.30 ** 23.13 

First-year height (cm) 40.98 A 36.76 

First-year height growth (cm) 11.68 * 13.62 

Survival in May (percent) 55.60 ** 99.00 

First-year survival (percent) 38.60 90.00 

'~ean height and growth only on those seedlings surviving at the 

end of the first growing season. 

**,*Means are significantly different between bareroot and 

containerized seedlings (p ( 0.01) and p 5 0.05 respectively. 

desired. The mean height of the seedlings was 

36.9 cm, the pruned taproot 16.98 cm long, and 

mean root collar diameter 0.63 cm (Table 1). 

The desired seedling height was 25.4 cm. Thus, 

the seedling height was 45 percent greater. 

Because the seedlings were so large and 

shoot-root ratios out of proportion, the 

relationships of the bareroot seedling 

characteristics with field performance should be 

viewed with caution. Results of this study 

further substantiate that seedling morphological 

shoot and root characteristics are correlated , 

with field performance and that the shoot-root 

ratio is very important for survival and growth 

of bareroot seedlings. 

Performance of Containerized Seedlings 

In contrast to the bareroot seedlings, only 

three root and shoot characteristics of 

containerized seedlings were correlated to field 

performance of the outplanted trees (Table 4). 

The lack of correlation was probably due to the 

uniformity of the containerized seedlings, 

especially their confined root systems. The 

number of lateral roots was positively 

correlated with survival but not to height 

growth. Kormanik (1985) suggested that the 

number of lateral roots on sweetgum (~iquidambar 

styraciflua L.) seedlings could be used to 

indicate performance after outplanting. 
Table 3. Correlations between loblolly pine bareroot seedling shoot and 

root characteristics and measurments taken after one year in the field. 

First-year field measurements 

Seedling characteristics Height Height arowth Survival 

--- Correlation coefficients - - - 

- Shoot 

Shoot 1 ength ( cm) 0.54** -0.28** - 0,322st 

Shoot volume (ml) 0.47** -0.32** -0.37a"x 

ToEal shoot-root vol. ratio 0.52** -0.32** -0.43n& 

Pruned shoot-root vol. ratio 0.51** -0.25* -0.28na 

. - Root 

Root collar diameter (cm) 0.27** -0.20 -0.18 

Total taproot length (cm) 0.16 -0.25* -0.36** 

Pruned taproot length (cm) 0.27** -0.22 -0.24* 

Number major lateral roots 0.26* -0.15 -0.11 

Average lateral length (cm) 0.12 -0.10 -0.08 

Total root volume (ml) 0.24* -0.21 -0.17 

Pruned root volume (ml) 0.30** -0.22 -0.24" 

*Simple linear correlation coefficients were significant at the 0.05 

level. 

**Simple linear correlation coefficients were significant at the 0.01 

level. 

Survival of the containerized seedlings (90 

percent) was over twice as great as that of the 

bareroot seedlings (Table 2). We believe the 

higher survival of the containerized seedlings over the bareroot seedlings was most likely a 

function of the optimal size and condition of 

the seedlings. The mean shoot-root volume ratio 

of the containerized seedlings was 2: 1, a more desirable ratio than that of the bareroot 

seedlings. 

Although both mean initial height of the 

containerized seedlings and height at the end of 

the first growing season were lower than the 

mean heights of the bareroot seedlings, 

containerized seedlings exhibited greater 

average height growth, This implies that the 

containerized seedlings were able to adjust to 

field conditions and to continue growth at 

faster rates than bareroot seedlings. 

Operational Progeny Testing 

'he bareroot seedlings exhibited no significant family variation in height, height 

growth, or survival. In contrast, family 

variation among the containerized seedlings was 

highly significant for height and height growth 

at the end of the first growing season. 

Survival was high for the containerized 

seedlings and no significant variation among 

families was apparent. 

The contrast in family variation between 

seedlings produced as bareroot versus containerized stock indicates that establishing 

a progeny test from one type of seedling versus another can have a profound effect on the 

outcome of the test. In this case, the 

disproportionate size of the bareroot seedlings 

greatly influenced survival and growth and made 

the test virtually unuseable for genetic 

purposes. However, the containerized test was a 

viable progeny test. The seedlings were uniform 

in size and quality and survival was high. An 

underlying objective of this study was to 

determine if a containerized seedling progeny 

test would reflect family performance when 

progeny were outplanted as bareroot seedlings. 

In this study, the containerized test did not 

reflect the results of the bareroot seedling 

progeny test, a test which theoretically was 

similar to operational planting. However, the 

bareroot seedlings planted in this study were 

not the desired seedling size; thus, the results 

of this comparison should be viewed with 

caution. 

CONCLUSIONS 

Bareroot seedling shoot and root 

characteristics were generally positively 

correlated with first-year height but negatively 

correlated with height growth and survival. 

However, because the average bareroot seedling 

in this study was larger than the optimum, the 

relationships should be viewed with caution. We 

believe the shoot-root ratio was an important 

factor in the poor survival and growth of the 

bareroot seedlings. 
Table 4. Correlations between loblolly pine containerized seedling 

shoot and root characteristics and measurements taken after one year in 

the field, 

First-year field measurements 

Seedling characteristics Heiaht Height growth Survival 

- - - Correlation coefIicients - - - 

Shoot 

Shoot length (cm) 0.08 -0.26f: -0.08 

Shoot volume (ml) -0.07 -0.05 -0.09 

Total shoot-root vol. ratio 0.07 -0.03 0.00 

- Root 

Root collar diameter (cm) -0.07 -0.11 -0.20 

Total taproot length (cm) 0.24* 0.19 -0.07 

Number major lateral roots 0.09 -0.04 0,29~& 

Average lateral length (cm) 0.07 0.10 -0.04 

Total root volume (ml) -0.16 -0.05 -0.18 

fcSimple linear correlation coefficients were signiiicaqt at the 0.05 

level. 

&*Simple linear correlation coefficients were significant at the 0.01 

level. 

Only three characteristics of the 

containerized seedlings were significantly 

correlated to field performance of the 

outplanted seedlings. The lack of correlation 

was probably due to the uniformity of the 

containerized seedlings. 

Mean survival at the end of the first 

growing season was 39 percent for the bareroot 

seedlings and 90 percent for the containerized 

seedlings. The bareroot seedling shoot-root 

ratio was apparently too large (7:l) which 

resulted in poor survival and growth. The 

shoot-root ratio of the containerized seedlings 

was more optimal (2 : 1 ) and survival and growth 

was superior to the bareroct seedlings. 

Bareroot seedlings exhibited no significant 

family variation in height, height growth, or 

survival. Genetic variation may have been 

masked by the problems encountered with the size 

of the seedlings. In contrast, family variation 

among containerized seedlings was highly 

significant for first-year height and height 

growth. In this study, the containerized 

seedling progeny test did not reflect the 

results of the bareroot seedling progeny test. 

LITERATURE CITED 

Barnett, J. P. 1978. Advances in container 

production of planting stock. Pages 

167-175 C. A. Hollis and A. E. 

Squillace, eds. Proc. of the fifth North 

American forest biology workshop, Univ. 

Florida, Gainesvilie, 

Burdett, A. N. 1979. A nondestructive method 

for measuring the volume of intact plant 

parts. Can. J. Forest Res. 9:120-122. 

Duryea, M. L., and T. D. Landis, eds. 1984. 

Forest nursery manual: production of 

bareroot seedlings. Martinus Nijhoff/Dr. 

W. Junk Publishers, The 

Hague/Boston/Lancaster, for Forest Research 

Laboratory, Oregon State Univ., Corvallis. 

386 p. 

Kellison, R. C., and R. Lea. 1983. Progeny 

test methodology: raising the seedlings. 

Pages 16-22 & Progeny testing of forest 

trees. Proc. of workshop on progeny 

testing. Regional Proj. S-23, South. Coop. 

Ser. Bull. No. 275, Auburn Univ. 

Kormanik, P. 0. 1985. Can lateral root 

characteristics be a major factor in 

assessing seedling quality? Pages 290-297 

- in Proc. 18th South. Forest Tree Improv. 

Conf., Long Beach, Mississippi. 

Leaf, A. L., P, Rathakette, and F. M. Solan. 

1978. Nursery seedling quality in relation 

to p1anta:ion performance, Pages 45-51 

E. Van Eerden and J. M. Kinghorn, eds. 

Proc. of the Root Form of Planted Trees 

Symposium, British Columbia ~inistryl~an. 

Forest Serv., Victoria. 

Stein, W. I., J. L. Edwards, and R. W. tinus. 

1975. Outlook for container-grown seedling 

use. J. Fcr. 73(6):337-341. 

Tinus, R. W. 1978. Root form: what difference 

does it make? Pages 11-15 in E, Van Eerden 

and J. M. Kinghorn, eds. Proc. of the 

Root Form of Planted Trees S>?nposium, 

British Columbia ~fnistry/~an. Forest 

Serv., Victoria. 
USDA Soil Conservation Service, 1970. 

Descriptive legend for the soil survey of 

J. G. Lee, Sr. Memorial Forest, 

Franklinton, ~ouisiana. 

van Buij tenen, J. P., and W. J. Lowe. 1982. 

Use of containerized seedlings for progeny 

testing. Pages 145-148 R. W. Guldin and 

J. P. Barnett, eds. Proc. of the Southern 

Containerized Seedling Forest Tree Seedling 

Conference. South, Forest Exp. Stn., USDA 

Forest Serv. Gen. Tech. Rep. SO-37. 

Wakeley, I?. C. 1954. Plan1;ing the southern 

pines. USDA Forest Serv. Aric., Monogr. 

18, 233 p. 

Wllder-Ayers, J. A. 1986. Bareroot versus 

containerized root systems: a study of 

half-sib families of loblolly pine (Pinus 

taeda L.) seedlings. Y.S. thesis. La. 

State Univ., Baton Roug~. 99 p. 
EFFECTION OF ChRBOS DICXSDE EXRECHMENT ON GROWTH AND YLD 

SURVI17AL OF GOSTALKER-GXOb'P; PTKUS TAEDA L. SEEDLINGS 

William A. Retzlaff, Ansel E. Mller and Joe E. ~oler' 

ABSTRACT.--This in\-estigzition examined some effects of 

increased atnospheric carbon dioxide levels on container-grown 

loHolly pine (Pinus taeda L.) seedling growth and development. 

Seedlings were grown In environment chambers supplied with carbon 

dioxide-concentrations of 175, 350, 700, and 1400 ppm. A 4 x 4 

Latin square experimental design with four 90-day replications and 

Lour environment chambers was employed. At ten-day intervals 

during each replication, a sample of 9 seedlings from each 

treatment was used to quantify seedling growth and development. 

Following completion of each replication, 100 seedlings from each 

treatment were out-planted to determine field survival. 

Seedling morphology was found to be significantly (a = 0.05) 

influenced by increasing carbon dioxide concentration. Total 

seedling height, root collar diameter, and stem, shoot, root and 

total dry weights all increased with increasing carbon dioxide 

cuncentration. Response analysis of 90-day results suggests that 

maximum growth occurs when carbon dioxide concentration is 

approximately 1000 ppm. No differences in field survival occurred 

in the first year out-planting from replications 1, 2 and 3 

(Surtival > 77% in all treatments). Another replication will be 

evaluated for survival after completion of a growing season. 

Fertilization of forest tree seedlings has 

generated considerable interest. Most research 

has dealt specifically with mineral nutrient 

fertilization for bare-root seedling production. 

However, production of container-grown forest 

tree seedlings is being explored because it 

presents opportunities to supplement bare-root 

seedling production (Raisch, 1981). Beneficial 

features of container-grown forest tree seedlings 

include uniform growth rates, fast crop rotation, 

extended planting seasons and good field 

performance (Hahn, 1981). Furthermore, some 

species such as true firs, hemlock, redwood, 

ctc., may be easier to grow in containers than in 

bare-root nurseries. 

Most container-grown tree seedlings are 

produced in greenhouses, The greenhouse 

environment can be controlled and some growth 

factors can be optimized (Tinus, 1974; Tinus and 

McDonald, 1979). "en water and mineral 

nutrients are optimal, an increase in carbon 

dioxide concentration is usually accompanied by 

at least a temporary increase in growth (Kramer, 

1981). Increasing atmospheric carbon dioxide 

concentrations can be considered analagous to 

fertilization. 

Atmospheric carbon dioxide enrichment has 

been used primarily in agricultural crops with 

less emphasis on woody plant species. Previous 

research on the effects of atmospheric carbon 

dioxide enrichment on coniferous species has " 

utilized white pine (Pinus strobus L.), ponderosa 

~ine (Y. ~onderosa Laws). blue sDruce (Picea - L , , 

pungens Engelm.), Douglas-fir (Pseudotsuga 

menziesii Franco), Scotch pine (I?-. sylvestris 

L.), lodgepole pine (P. contorta Douglas), and 

sitka spruce (Z, sitchensis [Bong.] Carr.) 

(Funsch et al., 1970; Tinus, 1972; Purohit and 

Tregunna, 1976; Alden, 1971; Canham and McCavish, 

1981). Generally, these are northern and western 

species; the major southern species have not been 

studied. 

Some information concerning growth of 

loblolly pine seedlings in enriched carbon 

'paper presented at the 4th Biennial Southern dioxide atmospheres does exist (Tolley, 1982; 

Silvicultural Research Conference, Atlanta, Rogers et&., 1983). These investigations were 

Georgia, November 4-6, 1986, primarily concerned with the effects of rising 

global atmospheric carbon dioxide on living 

'~raduate Research Assistant and Assistant systems. The use of carbon dioxide fertilization 

Professor, Department of Forestry; and to enhance growth of container-grown loblolly 

Instructor, Department of Experimental pine seedlings is an area that needs additional 

Statistics, Clemson University, South Carolina, study. 
During photosynthesis, carbon dioxide 

molecules are continually removed from the air 

surrounding plants and fixed into photosynthetic 

prducts (Wright and Lemod, 1970). As a result, 

carbon dioxide concentration decreases in the air 

near plant surfaces. Even though conditions for 

photosynthesis may be favorable, this decrease in 

carbon dioxide concentration is a common cause of 

suboptimal photosynthetic rates (Salisbury and 

Ross, 1978). This concept of carbon dioxide 

depletion is especially important in greenhouse 

culture. Frequently, greenhouse crops lack 

enough carbon dioxide for maximal growth. 

Methods for applying carbon dioxide in the 

greenhouse have ranged from such things as 

compost piles to burying dry ice in the soil 

(Pallas, 1970). Many greenhouses in America have 

moved into an era of using compressed carbon 

dioxide or carbon dioxide generated from fossil 

fuels. 

This investigation examined some effects of 

enhanced atmospheric carbon dioxide levels on 

growth and development of container-grown 

loblolly pine seedlings. The primary objectives 

of this study included: (1) Quantify growth and 

development of container-grown loblolly pine 

(It. taeda L.) seedlings in enriched carbon 

dioxide atmospheres and (2) Determine field 

survival potential of container-grown loblolly 

pine seedlings that developed in a carbon dioxide 

enriched atmosphere. 

MATERIALS AND METHODS 

Airtight chambers were used for growing 

seedlings in enriched carbon dioxide atmospheres. 

Seedlings in these chambers were periodically 

sampled to measure the impact of carbon dioxide 

treatments on seedling growth. After a 90-day 

growth period, the seedllngs were planted in the 

field. 

An Apple IIe@ microcomputer was programed, 

using Basic language, to sequentially open a 

solenoid valve, A diaphragm pump was used to 

draw chamber air through the tubing and DrieriteB 

dessicant into an infrared gas analyzer (IRGA) 

(Beckmans Model 865). The IRGA continually 

relayed an analog output 10 to 5 volts) to an 

analogldigital converter (Applied Engineering@) 

in the computer. Utilizing the Basic program, 

this volt signal was converted to a pprn carbon 

dioxide value by the analogjdigital converter. 

The microcomputer was programmed to take 9 

sample values at one second intervals, average 

them, and compare them to a tenth value. If the 

average was within 10 ppm of the tenth value, it 

was accepted. Otherwise, this step was repeated 

until the programed condition was met, -When the 

condition was met, the carbon dioxide level was 

stored in memory for later use. Stored ppm 

values for each chamber were averaged hourly and 

printed out on paper. 

The accepted carbon dioxide reading was then 

compared to a programmed concentration (350, 

700, ... ppm) according to the treatment assigned 

to that particular chamber. If the sample carbon 

dioxide value was below the programmed 

concentration, the microcomputer activated a 

second solenoid valve connected to a carbon 

dioxide cylinder and injected pure carbon dioxide 

into the chamber. The amount and duration of 

injection was determined by the deficit between 

the programmed and sample reading. If the sample 

value for a given chamber was greater than the 

programmed reading, the sampling solenoid valve 

was closed. At this time the computer opened the 

sample solenoid valve of the next growth chamber 

and the measurement and injection processes were 

repeated. Growth chambers were monitored 

sequentially in this manner. 

Carbon Dioxide Treatments 

Chamber Design 

Four insulated growth chambers were 

constructed using upright freezer bodies with 

doors removed. Freezer bodies were laid on their 

back and clear plexiglass sheets, 0.64 cm thick, 

replaced the doors as chamber tops. Temperature 

was kept below 27OC inside the chambers by a 9100 

btu Carrier@ air conditioner placed in an opening 

cut in one end of the chamber. The air 

conditioners were sealed from external air by 

caulking so that only internal air circulation 

and cooling would occur. 

Carbon Dioxide Monitoring Svstem 

Carbon dioxide concentration was controlled 

by a modification of designs by Patterson and 

Bite (1975) and Carter (1982). In this system, 

the growth chambers were connected to a carbon 

dioxide monitoring system via plastic tubing and 

solenoid valves that could be opened and closed 

to allow air passage. 

Carbon dioxide concentrations of 175, 350, 

700 and 1400 ppm were chosen to be the four 

programed set points or treatment rates. Each 

treatment was randomly assigned to a growth 

chamber. Since each treatment could only occur 

in one growth chamber at a time, the entire 

experiment was repeated four times in order that 

all treatment rates could occur in all growth 

chambers. A Latin square design was used so that 

differences between chambers as well as 

replications could be removed from experimental 

error. Length of each replication was 90 days. 

Two replications (I and 3) of the experiment were 

grown under artificial lights (metal ha ~d 

with light intensities of 650-700 pE s- I' m- 511amps 

indoors using a 14-hour daylength. The other two 

replications (2 and 4) were grow o tdoors in -? -Y natural light (up to 2000 uE s m ) during 

spring and summer. 
Seed ana Culrural Treatments 

At the beginning of each replicatioc, 

loblolly pine seeds from an orchard seed source 

(S.C. State Forestry Commission) were germinated 

in flats of builder's sand. When radicles were 

1-4 cm long, the seedlings were transplanted into 

115 cu. cm Leach-cells (Ray Leach "Cone-tainer" 

Nursery, Canby, Oregon) containing a 2:2:1 

mixture of fine grade peatmoss (spaghnum), 

vermiculite (grade i\2), and perlite (particle 

size 1-3 m). Three filled trays, each having 98 

containers, were then set inside each growth 

chamber. During each 30-day replication, 

seedlings were irrigated approximately every 3 

days. Periodically, seedlings were supplied with 

a solution of Peter's 20-20-20 fertilizer with 

micronutrients (0.5 gll). 

Growth Measurements 

Beginning at cotyledon emergence and at 

10-day intervals for 90-days, 9 seedlings from 

each treatment were selected for growth analysis. 

Total seedling height, root collar diameter, and 

dry weights of needles, stems and roots were 

determined for each seedling. 

Field Out-planting 

At the end of each replication (90-day 

growth period) 100 seedlings per treatment were 

planted in the field using dibbles. The first 

replication was out-planted in a nursery bed at 

the Clemson University Forestry Department 

Nursery. Replications 2, 3, and 4 were all 

out-planted on a rootraked and windrowed upland 

piedmont site on the Clemson University 

Experimental Forest. In all out-plantings, 

twenty trees from each treatment were planted in 

each of five blocks. Survival of the out-planted 

seedlings was determined following the end of the 

first growing season. 

RESULTS AND DISCUSSION 

Programmed carbon dioxide treatments were 

maintained by a monitoring system throughout the 

experiment period. However, the system provided 

actual determinations of the mean carbon dioxide 

concentration in each chamber/treatment 

combination during each replication (Table I). 

Carbon dioxide values for treatments 350, 700 and 

1400 were near the programmed goals. Unfortunately, actual carbon dioxide values for 

treatment 175 were close to ambient carbon 

dioxide levels and consequently, near values for 

treatment 350. Therefore, the low treatment 

failed to "starve" the seedlings, which was the 

initial plan for this treatment. 

Seedling measurements for each carbon 

dioxide treatment were averaged across all 4 

replications and plotted over the 90-day growth 

Table I. Carbon dioxide concentrations for each 

chamber (treatment) during each replication. 

- 

Goal Rep1 Rep2 Rep3 Rep4 OverallMean 

period. Growth responses were examined using 

actual mean carbon dioxide treatment values, The 

typical response to carbon dioxide treatment is 

illustrated by seedling total dry weight (Figure 

1). The ANOVA procedure for a Latin square 

design showed significant differences in response 

to atmospheric carbon dioxide enrichment for 

seedling morphological characteristics. 

Separation of response did not occur in most 

cases until 40 days into each replication. 

Separation at this time was between the two 

lowest and two highest carbon dioxide treatments. 

Separation of all 4 carbon dioxide treatments was 

detected at 70 days, and differences among 

treatments increased for subsequent sampling 

periods. However, because there was a 

significant difference in growth response due to 

location, that is replications 1 and 3 in 

artificial light and replications 2 and 4 in 

natural light, data was divided into two groups 

according to lighting conditions during each 

90-day growth period for further analysis. 

Figure 1. Total dry weight response of seedlings 

exposed to four carbon dioxide treatments over a 

90-day period. 
AS ISSZCWT ISTO THIPXISG VOUXC SLASH PIFIE STRS3S MITE ~12~' 1 

K. $!, Johanscn and D. D. WadcAbstrac~.--Unwanted young slash pines can be elininat2d from 

a stand with a prescribed fire if hrning takes place before 

the basal stem diameters 16 inches above ground level) of 

target stems reach 1.2 inches. This concLusiun is predicated 

on £lane heights always excecding 6 inches as the fires 

proqress through a stand. 

Despite the best efforts of silviculturists, other end of the plot at l1:36 am {fire traveled 

young pine stands are often too dense. Favorable 142 feet). During the burn, the ambient 

weather and a large seed crop lead to overly temperature remained ac 57' F., and the 

dense stands produced by seed-tree, shelterwood, relative humidity IRH) was 62 percent. Nean 

and seed-in-place systems. Volunteers from blown flame height was 1.5 feet. The mean fuel weight 

seed lead to overcrowding of plantations. consumed during the burn was 3.0 tons per acre. 

Prccommercial thinning is expensive, but nay be 

necessary to avoid stagnation. Judicious use of 

prescribed fire often :night get the job done at a 

low cost. Before it can be used, however, 

foresters need to know what conditions are needed 

to kill some trees without seriously injuring 

others. Variables to be considered are stem 

size, fireline intensity, and fire residence 

time. Some very useful experience with fire 

thinning was gained in the stildy described here. 

METHODS 

Two 8-year-old slash pine (Pinus Elliottii 

EngeLm. var elliottii) plantations were chosen 

for burning during the winter of 1985-8s on the 

Dixon Xemorial State Forest nejr Waycrosq, 

Georgia. These stands had, in addition to the 

planted trees, numerous voiunteers that had 

seeded in from nearby stands. 

The first srrand, on Melton Road, was planted on 

beds 10 feet apart at a 6 foot spacing (726 

trees/acre). Volunteers increased stocking most3 

than tenfold in places. In fact, the stand was 

so dt>nse that crown closure was completc~ ~n most 

plnccs, and pint needle Litter was thc primary 

fuel on the forest floor. The planted tret,s 

averaged 3,0 inches d.b.h., but ranzed from 1.3 

to 4.3 inthts. The voiiinteers were all younger 

and ranged fram 2 feet in height to 2,4 inches 

J.b.b. A barkfirc w~~s ignited on ?larch 6, 1986 

at 10: 00 am, and thc Ltaad flames reached rrke 

7 

A Paper presented at the Fourth Biennial 

Soxthern Silvitul tnrai Research Conferrnrc, 

Atlanta, Georgia, Kovember 4-6, 1986. 

2 

Research Forester and Project i,zadc.r, 

respectively, Sou theastern Forest 1:xperiment 

Stat~on, Southern Forest Fire LaSoratory, Dry 

Branch, GA 31020. 

The second plantation, also planted at 6- x 

10-foot spacing , bordering on Cowhouse Road had 

nrlmeruus voliinteers sieded in from an older, 

neighboring stand ti~at has since b~cn cut. In a 

few small areas the volunteer tree density 

exceeded 10,000 trees per acre, but the 

population was much less in most of the stand. 

Available fuel was mainly a thick stand of 

broomsedge (Andropogon virginicus t. var 

glaucvpsis (Elliott) Nitche.), An avtarage of 2.2 

tons of fuel per acre were consum~d in burning. 

Two 1.5 acre burns took place bc~tween 2:00 and 

5:WQ pm on Xarch 6, 1986. Whcn the first plot 

was ignited at 2:OC pm, the ambient temperature 

was 5:' I?. , and the I!Ii was 4l percent. By the 

tine the serond plot was ignited ar 4:Og pm, the 

ambient tmperature had increased to 72 F., and 

the RB was 32 percent. Xean flame height 

exceeded 3 feet, 

One week after the burns, each plantation was 

revisited to select and tag trees for later 

observation of trce survival and growth. 

Selected trees were numbered and tagged, and then 

d.h.h. (if they were tail enough) and diameter of 

thr main stea at a point 6 inches above ground 

liwcl $]<>re mcasured and recorded. Tl-iis point on 

the sten was well within the flane envelope 

dtlring t;:r fir< passaqi and was thought to bc 

riprestntaiive of -hc stea portion where heat 

girdline, if 11: occi~rred, worrld tak~ place. In 

adlit ion, the fraction of need? es s(-orchcd ihcat 

Rilltd) by the fire was recorded as well as the 

fraction of 1 ive nt.c.dl es actually consumed by the 

Elawes. Fir6 damagc to :he tres crown is mere 

rasily assessed I week after the biirn because the 

heat-killed needles have turned br~w? but ha'7e not 

yet absr*isczd from the hra~-ich~ 

OR .Jc:Iy z2, 1986, aSout fi montlls artrr the barn, 

each taggcd trcsc in both plantations was visited, 

and its condition was noted. 
To derive a measure of the resistance of young 

pine stems to heat girdling from fire, we had to 

eliminate the possible confounding effect of heat 

damage to the crowns which could also kill the 

tree. The high temperatures required to cause 

consumption of green needles will also frequently 

cause the death of a tree by heat girdling the 

upper stems and branches. Therefore, trees 

exhibiting any amount of needle consumption were 

not used in this analysis. Crown scorching, 

however, was disregarded because this type of 

damage during winter burns in southern pines has 

been shown to be nonlethal, though it can 

drastically reduce subsequent stem diameter 

growth (Wade and Johansen 19861. We also limited 

the analysis to trees having a stem diameter 

under 2.41 inches because no larger trees showed 

any signs of impending mortality. 

RESULTS 

Tree responses to fire in both areas were 

similar. Some 257 trees at Melton Road and 255 

trees at Cowhouse Road were included in the 

mortality analysis. The backing fire in the 

Melton Road plantation had an average spread rate 

of 1.5 feet per minute with only slight variation. 

Pireline intensity, I, a measure of heat output 

per unit length of fire front, averaged20Btulft-see 

limit usually recommended for backing fires in 

southern, natural fuels. 

Under the fuel and ambient temperature 

conditions at the Melton site, sufficient heat 

was developed to girdle the stem and kill 122 of 

the 130 trees (94 percent) 1 inch or less in stem 

diameter. As basal diameter increased above 1.00 

inch, a decreasing proportion of trees was killed 

until a tree girth of 1.50 inches was reached, 

above which no trees were killed (Table 1). 

Table 1. Clortality among llelton Road volunteer slash pines in gn 8-year-old 

slash pine plantation 4 months after backfiring in early March. I.10 tallied 

trees had orown consumption. 

Basal 2 Trees 

diameter Dead Total I.Ieasured Idortali ty 

Inches Nurnber Nuuber Percent 

All diameters 

'~vailable fuel = 3.0 T/AG; mean firweline intensity (I) = 20.4 Dtu/ft-sec, 

ange I = 17.2 - 29.0. 

'At 6 inches above ground line. 
The backing fire rate of spread in the grass 

fuel of Cowhouse Road plantation averaged G.2 

feet per minute (ranging berwee~ 3.0 and 5.0 feet 

per minute). The Rean fireline intensity was 40 

Btu/ft-sec, even though fuel loading was less 

here than at ?-ieltun Road. The difference was due 

to the fire spread rate in this grass fuel. being 

over twice as fast as in the pine needles at 

?felton Koad. Here tao about 95 percent of the 

stems less than 1 inch in diameter 6 inches above 

ground line were kiiled. When stem diameter 

exceeded 1.80 inches, 79 of the 82 sample trees 

(96 percent) survived (Table 2). 

The behavior of woodland fires can be expressed 

in several ways, but care must be exercised to 

choose the correct fire parameter if some 

particular fire effect on vegetation is desired. 

If some measure of heat input into the tree 

crowns is desired, Byram's f ireline intensity 

(I-Hwrl would normally be used because "I" is 

affected not only by "H", heat yield per pound of 

fuel, but also by "w", the amount of fuel per 

unit area, and "r"', the rate of fire spread. 

Thus, for a given site, the faster the fire 

spreads i increas ing "r") the hiqher "I" t~ill be. 

If "I" is increased, so is flame length, and the 

heat effect will extend higher into the crown. 

The parametdr "I" does not, however, reflect what 

happens within the flaae envelope near the 

ground. 

The amount of heat to which the lower stem of a 

tree would be exposed if it is in the flame zone 

is dependent upon the duration of exposure, known 

also as residence the. Flame temperature 

remains relatively constant regardless of flame 

depth or height, Duraticc of exposure is 

detcrmineJ by tzhe fuel continuity, fuel particle 

sizes, and fuel arrangement (Loose to compact). 

Residence time in a particular fuel type should 

fall within rather narrow limits. The pine 

needle fuel bed at Melton Road provided an 

average residence time of approximately 10 

seconds. This value can be observed directly or 

it can be determined from the fire spread rate 

and the horizontal depth of the flaming zone. 

Residence time for the Andropogon grass fire on 

Cowhouse Koad was also about 10 seconds. 

Tubie 2. Ifortality anon, Cowhouse Road volunteer sla:;ii plnes 2.7 ail G-year-old 

9las;i pine plantation 4 rnoncils after backs"irlnd In early lfarch. ;!o tallied 

trsees ilad cr*own coi?su~i~p tion. 

3asal2 Trees 

dianetei* Dead Total ::easured lioi.tality 

Inches --- -.--- iiIuidberl Zlumber Percent 

All diarnete~s 

'~vailable fuel = 2.2 T/AC; mean fireline intensity (I) = 40.0 Btu/ft-see, 

5ange I = 30.3 - 50.5. 

At 5 inches above ground line. 
These data have provi6ed insight into ef f rc t s 

af fire in ove4-stocked, young pine stands. With 

min%mum flame heights of 12 inches, we can expect 

to kill almost all pine trees with a basal 

diameter of I inch or less (6 inches above ground 

level when the outside ambient temperature is 55 B to 75 P, The trees we desire to save should be 

at Least 2 inches in diameter near the ground. 

When ambient temperatures are lower at burn time, 

the "kill ddiarmeterrr worrLd probably be solnewhat 

less, and when temperatures are higher as on a 

sumer day, trees somewhat larger should be 

killed, The killing of slightly larger sized 

saplings at Cowhouse Road was 8roGaBly because 

the ambient temperatare was 15 P. higher than 

at the Melton Road burn. 

These preliminary results highlight the need to 

make a decision about use of fire for thinning' 

early in a stand's development, A pine stem nst 

much over 1 inch in dairneter is all that is 

Likely to be affected, By the time the 

undesirable stems reach 2 inches in diameter, a 

means of elimination other than fire should be 

contemplated. 

LITERATURE ClTER 

Wade, Dale D, and R, W. Johansen. 1986. Effects 

of fire on southern pipe: observaticns and 

recomendations. USDA For. Serv. Gen. Tech. 

Rpt. SE-41. Southeast. For. Exp, Stn., 

Asheville, KC, i4p. 
Seedling total dry weight is again used to 

illustrate the typical response relationship to 

carbon dioxide enrichment under natural light 

conditions (Figure 2). Utilizing a parabolic 

relationship function, actual carbon dioxide 

values and corresponding growth achieved in each 

chamber showed a very good least-squares fit, 

From this equation the maximum dry weight of 3.2 

grams occurs at 979 ppm carbon dioxide. This 

value is approximately 602 greater than the dry 

weight achieved at carbon dioxide concentrations 

approximating ambient air. 

Table 11. Expected maximum growth at 90 days for 

seedlings grown in carbon dioxide enriched 

atmospheres under natural light conditions. 

Growth Opt imum CO Max imum Growth 

Heasurement concent rat $on 

Estimate t SE 

Estimate t SE 

Total Height 1115 t 213 268 t 10 mm 

Diameter 924 t 40 4.3 rt 0.1 m 

Root Dry Weight 920 t 99 1.2 rt 0.1 gm 

Shoot Dry Weight 1008 t 102 2.0 t 0.1 gm 

Total Dry Weight 979 t 57 3.2 t 0.1 gm 

Carbon Dloxlde Treatment (ppm) 

E 2.6- 

CR 

3 

9 

r 2.3. 

& - 

0 

C 

0 2.0. IFigure 2. Total dry weight of seedlings at 

90-days when exposed to four carbon dioxide 

treatments using natural light conditions 

(o = observed values, e = estimate values). 

Table 111. Expected maximum growth at 90 days 

for seedlings grown in carbon dioxide enriched 

2 atmospheres under artificial light conditions. 

Total Dry Welght = 3.2 + -2.6E-06 * (Cop- 979) 

Utilizing the same approach to describe 

responses of each morphological characteristic 

measured in this study, estimates were made of 

the optimum carbon dioxide concentration and 

maximum expected growth of container-grown 

loblolly pine seedlings. Under natural light 

conditions, optimum growth occurs in all cases at 

approximately 1000 ppm carbon dioxide levels 

(Table 11). Under artificial light conditions, 

1000 ppm again seems to be the best level for 

optimum growth (Table 111). However, the maximun~ 

growth under artificial light intensities was 

less than that under natural light conditions. 

Growth Optimum CO Maximum Growth 

Measurement concentrat $on 

Estimate + SE 

Estimate t SE 

Total Height 1305 t 424 161 t 11 mm 

Diameter 1012 t 41 3.5 t 0.1 mm 

Root Dry Weight 975 t 47 0.8 t 0.1 gm 

Shoot Dry Weight 1109 t 173 1.5 + 0.1 gm 

Total Dry Weight 1050 t 95 2.3 t 0.2 gm 

Table IV. Ffrst year field survival of carbon 

dioxide treated seedlings. 

Carbon Dioxide 

Treatment Rep 2 Rep 3 

Finally, the field survival of seedlings 

grown under atmospheric carbon dioxide enrichment 

was similar for all carbon dioxide pretreatmrnts --ppm-- -------------%-------------- 

with the exception of replication 3. Field 

survival for replication 2 and 3 was very good 175 99 A* 83 A 80 C 

considering it was a droughty year. Seedlings 350 99 A 81 A 87 BC 

from replication 4 are newly planted and their 700 100 A 81 A 92 AB 

field survival is not reported here. High field 1400 100 A 77 A 98 A 

survival cannot be fully attributed to carbon 

dioxide treatment and is probably associated with * 

low root disturbance of container-grown seedlings Means followed by the same letter are not 

when our-planted. significantly different (u = 0.05) using 

Duncan' s New Multiple Range Test . 
CONCLUSIONS 

1. The optimum carbon dioxide concentration 

for maximum growth of loblolly pine seedlings 

occurs at approximately 1000 ppm. 

2. Predicted growth at the optimum carbon 

dioxide concentration was 60 percent above that 

observed in ambient air. 

3. Field survival was generally not 

affected by carbon dioxide enrichment. 

LITERATURE CITED 

Alden, T. 1971. Influence of carbon dioxide, 

moisture and nutrients on the formation of 

Lammas growth and prolepsis in seedlings of 

Pinus silvestris L. Studia Forestalia 

93: 1-20. 

Canham, A. E. and W. J. McCavish. 1981. Some 

effects of carbon dioxide, daylength and 

nutrition on the growth of young forest tree 

plants. I. In the seedling stage. 

Forestry. 54(2):169-182. 

Carter, D. R. 1982. Effects of atmospheric 

carbon dioxide upon competitive interactions 

of a C3 and a C4 grass. Unpublished M.S. 

Thesis. Clemson University, Clemson, South 

Carolina. 

Funsch, R. W., R. H. Mattson, and G. R. Mowry. 

1970. Carbon dioxide supplemented 

atmosphere increase growth of Pinus strobus 

seedlings. Forest Sci. 16:459-460. 

Hahn, P. F. 1981. A historical overview of the 

use of containerized seedlings for 

operational reforestation. How did we get 

where we are today? Proc. Southern 

Containerized Forest Tree Seedling 

Conference. USDA Forest Service General 

Technical Report SO-37. p. 7-12. 

Kramer, P. J. 1981. Carbon dioxide 

concentration, photosynthesis and dry matter 

production. BioScience. 31(1):29-33. 

Pallas, J. E. Jr. 1970. Theoretical aspects of 

carbon dioxide enrichment. Trans ASAE. 

13:240-245. 

Patterson, D. T. and J. L. Hite. 1975. A carbon 

dioxide monitoring and control system for 

plant growth chambers. Ohio J. Sci. 

75(4):190-193. 

Purohit, A. N. and E. B. Tregunna. 1976. 

Effects of carbon dioxide on the growth of 

douglas fir seedlings, Indian J. Plant 

Phys. 19:164-170. 

Raisch, R. D. 1981. Getting Started. Proc. 

Southern Containerized Forest Tree Seedling 

Conference. USDA Forest Service General 

Technical Report SO-37. p. 13. 

Rogers, H. H., J. F. Thomas, and G. E. Bingham. 

1983. Response of agronomic and forest 

species to elevated atmospheric carbon 

dioxide. Science. 220:428-429. 

Salisbury, F. B. and C. W. Ross. 1978. Plant 

Physiology. Wadsworth Publishing Company, 

Inc. 422 pp. 

Tinus, R. W. 1972. Carbon dioxide enriched 

atmosphere speeds growth of ponderosa pine 

and blue spruce seedlings. Tree Planters 

Notes. 23:12-15. 

. 1974. Conifer seedling nursery 

in a greenhouse. J. of Soil and Water 

Conservation. 29(3). 

and S. E. McDonald. 1979. How to 

Grow Tree Seedlings in Containers in 

Greenhouses. USDA Forest Service General 

Technical Report RM - 60. 256 pp. 

Tolley, I,. C. 1982. The effects of atmospheric 

carbon dioxide enrichment, irradiance and 

water stress on seedling growth and 

physiology of Liquidambar styraciflua and 

-- Pinus taeda. Unpublished PhD. dissertation. 

Duke University, Durham, North Carolina. 

Wright, 3. L. and E. Lemon. 1970. The exchange 

of carbon dioxide between the atmosphere and 

the plant. Trans ASAE. 13:238-239. 
CONTAINERIZED WHITE PINE SEEDLING DEVELOPXMT 

FIVE YEARS AFTER OUTPLANTIN&/ 

21 R. L. Hay and J. C. RennieAbstract .--Nursery-grown 2-0 bareroot white pine seedlings and 7 month old containerized seedlings that had received various combinations of extended photoperiod and GO2 

enrichment were planted on the Cumberland Plateau in a 

randomized block design. Total height, stem caliper at the 

soil surface and biomass 02 stems and leaves were measured 

periodically. A cleaning was done after the third growing 

season. 

After five years, the 2-0 seedlings were significantly 

larger than the containerized seedlings. 3f the greenhouse 

culture treatments, the 24-hour photoperiod had the greatest 

positive effect on growth while the enriched C02 treatment 

depressed growth. 

INTRODUCTION 

Eastern white pine (Pinus strobus L) is one 

of the most important gymnosperms in the East. 

Within customary market fluctuations, the demand 

for white pine lumber has been consistent, with 

prices frequently higher than those for many 

hardwood species that occupy the same sites. 

Fjlite pine is also popular with Christmas tree 

growers. 

The slow, early growth of white pine seedlings extends time in the nursery required to 

2roduce quality plants. In Tennessee, nursery 

seedlings are dug as 2-0 bareroot stock, but 

other nurseries might offer 3-0 seedlings or 2-2 

transplants. White pine seedlings usually do 

not develop secondary leaves during the first 

growing season. The cotyledons are functional 

until the epicotyl begins to elongate and the 

primary leaves appear. The primary leeves provide photosynthate throughout the growing season 

and the overwintering bud develops by late-summer. 

Seedlings are considered too small for outplanting 

after only one year in the nursery. Durin~ the 

second year, secondary leaves develop and most 

seedlings attain sufficient size to survive outplanting. 

1 --/Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2/~ssociate Professors, Department of 

Forestry, Wildlife and Fisheries, The University 

of Tennessee, P.O. Box 1071, Knoxville, TN 

37901. 

Container-growl white pine seedlings have 

several advantages over bareroot nursery stock in 

certain situations. Quality seedlings can be 

produced in less than half the time required in 

a nursery. Seedling bed density can be readily 

controlled by choosing the appropriate container 

size. Mycorrhizal inocula of the appropriate 

fungus can be added to the growing medium. 

Fertilizer schedule control and minimal insect and 

disease problems are additional advantages of 

containerized culture. 

The purpose of the study reported here was 

to test survival and growth of seven month old 

containerized white pine seedlings compared with 

two year old, bareroot, nursery-grown seedlings. 

The plantation was established on Pickett State 

Forest (Hay and Rennie 1983). 

Greenhouse culture techniques for producing 

the containerized seedlings and the outplant ing 

design were previously reported (May 1981; Hay 

and Xeegan 1982; Hay and Rennie 1%3). Total 

height was measured annually. Stem diameter at 

the root collar was measured for each seedling 

after year two. Total, above-ground biomass was 

determined at two, three, and five years, based 

upon a pre-determined sampling design such that 

a 10 X 13 residual stem spacing occurred. Stems 

and leaves were dried at 70C. 

Initial site preparation had been effective 

in minimizing competing vegetation through the 

second growing season ('Ieegan 1981). However, by 

the end of the third growing season, 7irginia 

pine (Pinus -- virginiana L) wildlings were competing 

with the experimental white pines. Although it 
was not apparent at this early age w5at lasting 

effects the Virginia pine wcilld 'i-ra~ie ilsn itand 

co-,poiltior,, a cleaning ~n *.j.'?lcl; c a-$1 113i-ftc ;"~RL. 

was rcllrascd frori aF; woody stc~n toi7perltr~n wa5 

unifor~;;~ appiifrd to ail pl~es cutting ail 

the cnnpet ing s ters . Ptrbaccous -JC ze tat lop wds 

not treated. 

S-.. ,,:dl l trees lacking apical darriinance and 

unah !c to ~i>tgToW increasing ror:pt.t ikion in the 

face of impeadiiig droui-' ,nt ch,?ractcrized the 

con taincrizi-ii sc.eil1 ings after one xvcar in the 

fit id. 'The 2-0 5arc;reot trcc*s were ncw three 

vc3ars old, and beconing cstsbiishrd, 

Growth Relationships 

Survival 

Survival data were only meaningful prior to 

sampling for bioasss deterninations. Xortality 

of 2-0 bareroot seedlings was greater d~uring the 

first year than thc best containcrized seedling 

treat~ent (Hay and K~nnit. 1983). However, by tilo 

second year survival was similar for ail treatrlecb 

(Hay and Rennie 1983) . 

Compared to later outpldntings of containerized white pine seedlings on a variety of sites, 

the survival percentages for containerized seedlings in this study were low. Several factors 

were involved: the first growing season was hot 

and dry, the root plug was not well-developed, 

and the terminal buds failed to elongate 

immedidteiy after ouiplanting. 

Shortly after the seedlings were rlanted 

the wearher became unseasonably hot and dry for 

much of the growing season. Unfortun,l tel y this 

trend continued, intermittently during the entire 

experiment, with severe drought occurring again 

during the third growing season. ihe rscordbreaking drought of 1985-86 was a continuat ion 

of the conditions that occurred during much of 

the study. Soils on the study site were sandy 

with low organic matter content and low water 

holding capacity (Reegan, l98l), further dgbravating the drought effects to the seedlings. 

Failure of the root plug to remain intact 

during the planting operation was another prgblern. 

A pine bark:sand:vermiculite medium k7as used in 

this study and it was so fragile that extrrxc 

care had to be used during planting. In suhsequent greenhouse tests, which were not a part of 

this study, a peat:ver:r.iculite rnediulil was LISC~ 

with excel lent root plug deve lopnent . Survix;al 

on a variety of sites has been consistently 

higher in these later outplantings . 

rerhaps thc grcatest probie~ was the fdilurc 

of the containerized seedlings to n~alntain he lght 

growtll after outplant ing hecatrie dor,rancy relationships had bren alter~d during tilc gri c:~iioiiit. 

cil t~ire phase. Kornal daylsncrth during the i*;l;:t~r 

inonths is nct adequate ::or active t~rr~inal 

elongation so t\i seedlings rect>ive d either 24 hclir 

photoperiod or a burst of 1igi.t each ho~~r iif the 

dark period. When tht stediings wcrc qorc~d to 

the shadehouse a i ti^ weeks przor to iin tpia~r ing, 

they received light acccrding to thc photopLrioL 

of that early spring sedson. Apparently scne 

seedlings wept dormant in r~sponse to the ~liorte~r 

daylength, berarise n any tcrninals fai icu to 

eiongate during the first year in the ficld. 

,(.* 

! kc. 2-0 hareroot seedl ings were coiisistent ly 

and significantly larger than any of the ccntainerized seedlings (u = .G5j throughout the stcdy. 

They were two years old at outplanting, cornpared 

to sc-vrn i:lonths for the containerized seedlings. 

The size dif ferences were caintaincd. See f iguros 

i, 2, and 3. 

1utd'L hei~hts arc. presented in figure 1. 

The effects of extending the photoperiot in the 

greenhouse with a light so,Jrce designed to promote 

seedling growth produced significant height growth 

differences in thc second and fifth years after 

outplanting for thc containcrized treatments 

jci = .05) . 'The trend was very apparent in the 

other y~ars ds well; individudl degree of frt-edoni 

comparisons were within alpha = .10. ihe two 

24-hour photoperiod treatments liroduced the 

tallest containerized seedlings throughout the 

five years (fig. 1). 

When the containeri zed sc edlings were removed 

f ron the greenhouse, there werc no dif ft rences 

in seedling hcight according to photoperiod 

treatments (iiay and Keegan 1982). rile height 

differences in thc iitld that oec~lrred as early 

as thc sicond year after outplanting were due to 

scedl ing respoilrt~s to environmental sti~uli in 

the field. It's important to note that seedlings 

grow1 r:ndi.r 24-ilour photoperiod in the greenhouse 

had significantly higher biomass in both tops and 

roots ai ter Gelsen months (Hay and Keegdn 1982). 

Height growth irt young white pine is largely a 

function of stored entsrgy and these se~dlings 

appeared better suited for growth in the field 

than the others even if there Idere no inltial 

height diffcrenct,s. 

Seedlings grown in the carbon dioxide (602) 

c.nriched at:r,osphcre under na tural photoperiod 

during grrcnhacse ci.ilture were the shortest 

after five years in the field (fig. 1). The 

positive effect of 24-hour photoperiod within the 

CI:~--i.nrichc~d ~ti.losphere somewhat balanced the 

snp~r~~ssi*,-c efft.,cts of CO7, for sccdi ings rc- '... 

ceiving light and i:02 were always sinilar Pr: sizv 

to th~s~' gram ::ncier natural photoperiod without 

a 

.AzJdirig CO:, S~ring the grt?n'hci:~se cu! trirc 7- ,ii,<i.,,. - '- r significantly depressed !(I = .Oij seedling 

height growth both in the grcenhaiise and after 

outplanting. :.here is ne apparent reasor. for 

this, for growing plants in greenko~isrs in GO2 

inr ichrd atrnosp'r~eres is a long-standing hsrt i- 

!-iii triral practice. White pine scedi iiigs have 
st~dy ( tig. 2) . Lon taherized seedii?g diameter 

growth after autplznting was influsnced by 

4rce-"tJ 3cc r~~if*lr"i tr~at-tnts. 

Natural 

Photoperlod a 24 Hour 

Photoperbd $B 

Years after outplanting 

Figure 1.--Total height growth of 2-0 bareroot 

and 7 month old containerized white pine 

seedlings through 5 growing seasons on the 

Cumberland Plateau. 

responded positively to 1000 ppm of GO2 (Funsch 

et a1 l970), as have many other species. Yet 

these seedlings were significantly shortest 

(a = -05) at outplanting and two years hence 

with the trend maintained for five years. 

Seedling age was a major source of size 

differences between the 2-0 bareroot and the 

containerized seedlings. Using seedling agr 

from seed germination and not plantation establishment as the basis for comparisocs, the 

containerized seedlings werE similar in total 

height to the bareroot seedlings (fLg. 1). For 

example, at age four from germination the cnntaiw 

erized seedlings averaged 84 cm and the bareront 

seedlings were 69 cm call (fig. l), ?hs sare 

trend was true throughout the srudy, but less 

well defined at the last measurefistant. 

Diameter Growth 

Stem diameter growth relationships wzre 

similar to those of height development. The 3-0 

bareroot seedlings were considerably l arger than 

containerized seedlings at outplanting and they 

maintained that advantage @ = '05) through the 

containerized secdllqgs grown in the C02 

cnrichta greechodse bad significantly smaller 

ei~neteri the sccond pear dter outpi~~~ting 

.J = 05 j . The co;~bir~ation ofnatural photoperiod and enriched C02 pr~duccd the saallesr 

seellings. Sc~dlings fro^ tkc CQ2 greenhouse 

treat-ie7t remainc? ST aii,st thrb~ghout the stuc?y, 

but rhe differences wcre not significant at the 

5' Level. 

The: 2&-hour photoperiod treatnent had a 

positive relationship to 21 ametcr grewtb. Three 

years after outplanting, the 24-hour photoperiod 

seedlings were significantly larger = .05) 

than thos~ receis-ing natural pli~ toperiod. This 

trend continued throughout the study; the best 

diameter development occurred for those seedlings 

receiving 24-hour photoperiod in ambient C02 

dtmoaphere . 

Using age since seed germination for 

comparisons between the 2-0 bareroot and containerized seedlings had as large or larger diameter 

than the 2-0 hareroot. Specif icaily, at year 4 

the containerized seedlings were as large as the 

Treatments 7 

j( Control (2-0 bareroot) / Ambient C02 CO2 Enrk-nt / Natural 

Bhotcynrid 

24 Hour 

Phatwisd 

Years after outplantkg 

-. 

xgcre 2.--Stem caliper at the groccd for 2-0 

bareroct and 7 month old cdntainerized white 

pine seedlings through 5 gro~ing seasons on the 

Cunberland Plateau . 
2-Q seedlings at year 3 (fig. 2). At year 5 and 

year 4, respt ct ivrly, the containerized seedlings 

had larger diametzr. 

Ciameter growth rate increased tke fifth 

year For ail treatments in response to the 

cizaning whi~h rezoved crown competition from all 

treatments. Sote the slope changes in figure 2. 

>lost trees responded by expanding crowns beyond 

what would have been likely if the competing 

sprouts and i7irginia pines had remained. Diameter 

growth frequently increases after thinnings reduce 

crown competition in merchantable stands; apparently such responses can also occur in young 

stands. 

Biomass estimates were made from seedlings 

that were harvested at the root collar. Ovendry weights were analyzed for leaf and stem 

tissues and total dry weight (fig. 3) for years 

2, 3, and 5. The 2-0 bareroot seedlings were 

significantly larger ( JL = -05) than the containerized seedlings throughout the five years of 

the study. There were no differences within the 

containerized seedlings due to greenhouse culture 

treatments. However, the same trends existed 

for biomass that have been previously discussed 

for height and diameter, i-e., the containerized 

seedlings that were grcwn in 24-hour photoperiod 

and ambient C02 at~ospheres were consistently 

largest and the natural photoperiod plus C02 

enrichment produced thr smallest seedlings. 

The 2-0 bareroot seedlings appearedto be 

in a better position than any other treatment 

tc compete favorably on these sites at the 

termination of the study. The magnitude of 

biomass differences at year five (fig. 3) 

indicated that the 2-0 seedlings were well into 

the rapid growth stage that characterizes 

sapling-to-poie growth; additional growth increases 

will likely occur within thc next few years. I t 

was uncertain at year five whether the smaller, 

containerized trees would constitute a portion 

of the maturing canopy. Without the cleaning 

prior to year four, there would have been less 

opportunity for these small trees to have reached 

dominant canopy position. The larger containerized and the 2-0 bareroot seedlings have a 

firm pssition and will soon clos~ canopy over 

competing species. 

Dl SCUSS i Oh' 

Based upon the first fi-de pears of growth, 

~i?ntalncr;zcd white pine seedlings did not surpass 

tht 2-3 bareroot nrirsery stock. The nursery 

seedlings were larger in all n~easured variables 

and by the second year s1irvival was similar. 

However, there vere some extenuating circumstances 

t\at were particularly unfavorable toward the 

containerized seedlings in this test. 

i'hc age and related size differences clearly 

:avored the nursery stock which was outplanted 

Natwal 

Photoperiod 

jt Control (2-0 bareroot) 

Ambient 602 C02 Enrichment 

24 Hour 

Photoperiod a 

Years after outplanting 

Figure 3. --Above-ground b iomass development of 

2-0 bareroot and 7 mont? old containerized 

white pine seedlings through 5 growing seasons 

on the Cumberland Plateau. 

as 2-0 bareroot seedlings compared to seven-month 

old containerized seedlings. However, seedling 

size based upon age since germination instead of 

time since outplanting was quite comparable. 

The containerized seedlings were growing at 

satisfactory rates, even though they were slow 

to start growth after outplanting. 

Bud dormancy relationships in this study 

had been altered by the photoperiod treatments 

during greenhouse culture. In most cases, normal 

elongation of terminal buds did not occur soon 

after outplanting. Sometimes the bud remained 

toraily dormant, or some elongated a few eentir~etrrs without any leaf development, but most of 

them lost strong, central stem, apical dominance 

when one to several sprouts developed from buds 

at leaf axils. :hese sprouts supported primary 

leaves even tho~lgh secondary leaves had previously 

existed. New terminal buds formed on the sprouts 

at the end of t3e first growing season in the 

field and normal growth sequences occurred the 

following sprinq. For those seedlings with 

multiple shoots, it was another year before 

strong apical dominance was re-establ ished. 

Since this study was initiated, many changes 

have been made in our greenhouse culture techniques. 

Photoperiod treatments are not used past the 

cotyledon stage and the seedlings go dormant 
according to natural pi~oti:perio$ and teaperature 

stin~uli in the atltu::!ri af~er which rhry can be 

outplanti~d as .?c?r::;a-t stock or aftcr spring 

growth has begun. Ce:~t.iineriz~d seedlings st 

age two are aiqilar in size to 2-10 bareroot 

nursery stock, biit they have air cad!^ been 

establisi~ed in a plari tat Lon instead of rercaining 

in the nursery. There are sone advantages to 

such a headstart, if high survival and good 

growth rates are goals. 

runsch, K. 5,'. , R. i<. ,tfattsa~, and C, t:'. ."fowry. 

1970. 6O3 - supple~~nted atxosphere increases 

growth of Pinus - strobus - seedlings. For. Sci, 

16:459-460. 

;Liy, -1. L 

1381. Growth of e'istern white pine seedlings 

using greenhouse culture techniques, p. 46-49 

- In First Biennial Southern Silvicultural 

Research Conf., Proc. U.S. Forest Service, 

South. For. T:xp. Sta., Gen. Tech. Rep. SO-34. 

*:--, .LC?, -- &\. L. and J. id:. I;ce;;an. 

1982. Containerized white pine i-I: it~:r'ii 

ziethocis and o~tplanting sc~cci.ss i):~ t'clc* 

Sunherland Plateau, '!'ennr sse~,, p. 5!-'17. 

in Soiitheril Containerized Forest l'ree --- 

Seedling Cunf. 6. S. Forest Service, Seut1-i. 

For. I:<?. Sta., (:en. 'Tech. Pkp. SO-'57. 

Hay, K. L. dnd J. C. Rennie 

1983. Herg5t growth of containerized white 

pine on the Cuaberland Plateab, rennessie, 

;?. 126-133. - In Seconu Eiennrai Sot-thern 

Silvicultural Researck CoaE ., Proc. L, 5. 

Yorest Service, So it'iL;?ast. For. C:<p. Sta., 

Cen. Pech. Yep. L12--2&. 

keegan, J. K. 

1981. Containerized cultrirc of eaatem white 

pine. Xaster cf Science i hesls. Cn iv. [ f 

'Icnnessee, Knoxville. 55 p. 
Luivt:L jzIrriA SELI~LJ 1-C; STOrcAhlLIYY Ali~ &51:>'tAL~Ck 

;! j ,>kOlu'M-SPOT DLbEASE IPiPKOL',- , ATI1)TiUC; 

BENO~UL TO THE, EACKLL$G MEDIU~.~;/ 

James P. barnett and Albert G. Kaisg 

Abstract: Longieaf pine seedlings niavted in January after 1 

and 3 weeks 01 storage with and without ,.,eltomy1 in the packing 

rledium were evaluated for field performance during the following 

tall. The benomyl-clay mixture improved survival 7 and 60 percentage points over the clay slurry control for the 1- at~d 3-week 

storage treatments respectively. brown-spot occurrence was reduced 

by 8 percent at bott. sites followiug benomyl Zreatment, although 

untreared seedlings were only moderately infected with brown-spot 

needle. t)llg!rc. 

lAdditior,al lLeJ~?ords : dinus palustris llill., seedling survival, 

brown-spot disease control, Scirrhia acicola (Learn.) Siggers 

decent studies have shown that root-dipping in 

a clay-benomyl enla late^) mixture at the time of 

planting \rill provide systemic protection of 

longl~ar pine (Pinus palustrls i.li11.) seedlings 

frov brown-spot disease (Scirrhia acicola - (Dearn.) 

Siggers) for at least one year 

- --- in - 

the field (Kais 

&d Earnett 1584, Cordell i.1: al., 1984, Kais et 

al. 1986a and l"i86L). i't,>s treatment has improved 

survival rate and early hclght growth of the 

seedlings (Kais 1985, Kais et al. 1986b, Kais and 

barnet t 1484) . 

Longleaf ,irtcz seedlings frorr a single seed lot 

were ilfted rxom nursery beds in southern 

biis~~~tlppi irk early January 19d5. Seedlings were 

oivlaed into sublots for two storage periods and 

:or the application of the following five treat- 

*rents: 1) clay slurry control, 2) clay slurry 

t:itr! a benomyl dip applied at the tine of 

- '/Paper presented at Southern Silvicultural 

~;ese;;rcf, Confercnce, Atlanta, Georgia, 

:.iovertber 4-6, 1986. 

2' Iuarnett is Principal Silvlcul rt:rist, 

Pineville, LA 71360 and K'ais is Yrinciprl 

Plant Pathclogisrr (retired), Gulfport, I,:; 

39503, USDA-Forest Service, Southerri Y orest 

Experiment Station. 

planting, 3) clay slurry mixture with benomyl 

applied at tjme of packing, 4) peat-moss control, 

and 5) peat moss combined with a benomyl treatiaent, Benomyl was applied in a 10 percent mixture 

of benlatew WP50 and kaoli~ate clay. This 

resulteti in an approxiri~ate 5 percent a.i. of benomy1 in the clay sli~rry or dip. A 10 percent dilution ok benomyl in water was used as a dip prior 

to packing with peat moss for treatment 5. 

Seedlings were packed in Kraft-polyethylene 

bags at 350 se~dlings per bag and stored at 35' F. 

The first outplanting was made after 1 week of 

storage, whi3e the second was made about 3 weeks 

later. Seedlings were machine planted at a 5-by-5 

foot spring. Fnt~r rep1 ications of 100 seedlings 

(2 rows of 50 seedlings) were outplanted for each 

packlnq-stnraze tre3tnent on two different sites 

iu Central 1 ot~isiana. The first site was on the 

Cdtahoula Ranger District, Kisatchie National 

Forest. This area tiad heen clear-cut and planted 

v:th longleaf pine in l9rt2, httt the planting had 

been unsuccesstul. Yhis site had a moderately 

liii,h i~tciuence of brown-spot discase inoculum. 

The second outplanting site was on the Palustris 

Experic~ental Forest. lhis area had been clearcut 

several years previouily arid had been routinely 

kuurncd to re,;t~r.e woody-plant compe.tition. Brownspot inoculum was low on this site. 

Seedlinj; survival and brown-spot infection 

were measured in June ~ncl December following 

planting. The December data are reported here. 

Lrown-spot infection was determined by visual 

estimate of the proportional amount of needle 
tissue that was killed by the disease (Kais 1985, 

Kais and Barnett 1484, Kais et al. 198fa). 

Differences in proportions of survival and 

brown-spot infection were tested tor significance 

at the 0.05 level by analyses of variance. 

Duncan" multiple range test was used to evaluate 

treatment means. 

Survival ---- 

Outplanting site had considerable effect on 

longleaf pine seedling survival after one full 

growing season (table 1). Heavier grass and woody 

competition as well as greater brown-spot incidence occurred on site 1. Nevertheless, treatment 

effects followed the same trends on both sites. 

Both length of seedling storage and packing-medium 

treatments significantly affected seedling performance, Survival after 3 weeks of storage was 

markedly lower than after 1 week. The effect of 

storage varied greatly depending on packing-medium 

treatments. Storage x packing treatment interactions also significantly affected results at 

both sites. 

The clay-slurry and peat-moss controls had consistently lower survival at 1-week storage than 

any of the benomyl treatments (table 1). The 

magnitude of treatment differences was much 

greater for the 3-week storage treatment. The 

clay-slurry treatments averaged 19, 33, and 79 

percent survival for the control, benomyl dip at 

planting, and the clay-benomyl slurry, respectively. The peat moss control averaged 64 percent, triple that of the clay-slurry control. The 

addition of benomyl to the peat-moss treatment 

improved survival 13 percentage points. 

Brown-spot infection .------ --- 

at slte 1. On site 2, where infection levels 

were low, significant differences occurred due to 

lengths oi storrzge. 

Statistically signiticant t~iffcarenccs cccurred in 

pa~kirt~-%~ec ium trc-.;itrtrnt.; at both sites. 

(;~nc~ral ly, cclntrols had hieher i nfectson levels 

than the counterparts treated with benamyl. On 

site 1 where the brown-spot levels were higher, 

the infection rates ranged from 14 to 20 percent 

(table 2). benomyl treatment of seedlings reduced 

these levels to an average of 6 percent. 

The treatment of longleaf pine bare-root nursery 

seedlings with henomyl reduced brown-spot infection in the field as hat1 been reported earlier 

(Kais and Barnett 1984, Kais et al. 198ha). 

However, perhaps even more important js the improve 

ment in the storahilily of longleaf pine 

seedlings. The mapitude of beneficral response 

due to benomyl treatment is il.ir,)r~ssive. If these 

results are typical, rhe addition of benomyl to 

the clay slurry packing medjum may also he an 

effective meRns of irtpro3r-i nz ssr~rvival of 1 onqleaf 

pine plant inp; st-ock.. The ttse of hrnomyl could he 

important for overconij ng two of the major 

obstacles to sr~cct.sc;frll ~rtificial r~senrratjon of 

longleaf pi oe--1 ow srlrviva 1 and, slow initial 

height grnwth (Kais 1985). 

For the parking medium, it is mtich easier to 

incorporate henornyl in a clay sl~irry than in peat 

moss. because nmst rttsrsery managers now use tile 

clay slurry treatment, Chis probably will he the 

preferred method. Tt is inrerestin&: to note that 

the peat moss control proviued considerably higher 

survival than the clay slurry control. We have no 

sound explanation tor these differences. However, 

with the addition of h~nomyl to both treatments, 

no dif-ferences in sllrvi val occt~rred. 

The level of brown-spot infection on seedlings Additional studies are being conducted with 

at the end of the first year was higher on site 1 longleaf pine to confirm these results, to evaldue to a greater amount of inoculum initially pres- uate the response of other pine species, and to 

ent in the soil (table 2). Seedling storage had determine the mechanisms that may account for 

no effect on occurrence of brown-spot on seedlings these differences. 

Table 1.--Survival of longleaf pitie seedlirlgs aftex 1 year irk t1:e fielel 

____-_-_~____________-_.I_______-__-I_ 

Stored for 1 week Stored lor 3 weeks 

TreaL~e2.L -.--- -- -:-- ?Lt-%?- -;- s.? ?- -:2?%2--- 2- -S%%L L--?2L:-< LA=-- 

Clay slurry control 67c 81a 74b bd 30d 19d 

Clay witti benomyl dip 77abc 86a 81ab 2Uc 47 c 33c 

Clay-benomyl slurry 79ab 84a 81ah 75a C3a 79a 

Peat moss control 68 bc 84a 7 bab b2b bob 64L 

Peat with benomyl 8 1 a 85a 83a 74ab boa 77a 

- a/ For each column, values with the same letter are not significantly different 

(0.05 level) 
Table 2.--Bro~n-spot disease infection rates of loilgledi pine ser~llnj,s atttr h 

year in t!re fieldd 

- --------.. ----- -- - -- Stored I r.eck ___: Seorea 3 ~eeks 

Treatment : Site 1 : Site 2 : hvg. Site I : Sitc 2 : Lvtc;. --- ---- p- ----- ------------ - -- -I---_- _ _--______ ....................... rprtpnt------------------------ 

--- 

Clay slurry control 19.4a 3,5a 11.4a 14'. f;a 5,ba 12.h 

Clay with benomyl dip 5.9b 2.4bc 4.2b 5.5~ 4.7aC 5.1~ 

Clay-benomyl slurry 7.2b 2.lc 4.6b 5.8~ 2.7~ 4.2~ 

Peat moss control 16.5a 3.0ab ! .8a 14.2b 4.3d 5.2b 

Peat with benomy1 6.0b 2.iabc 4.4b 4.5~ 3.lc 4 .Uc 

For each column, values with the rare lerter are not signiiicantly d~ffereni 

(0.05 level). 

LITEKATURE CITED 

Cordell, C. h., A. G, Kais, J. P. barnett, and C. 

E. Affeltranger. Effects of benomyl root 

storage treatments on longleaf pine seedling 

survival and brown-spot disease incidence. In: 

Proceedings, Southern Nursery Conferences. 

Western Session: Alexandria, LA, 1984 June 

11-14. Eastern Session: Asheville, NC, July 

24-27. Atlanta, GA: U.S. Department of 

Agriculture, Forest Service, Southern Region: 

1984~84-88. 

Kais, A. G. Recent advances in control of brown 

spot in longleaf pine. Proceedings, 34th Annual 

For. Symp,, 1985 March 26-27, Baton Rouge, 

LA: LA, State Univ.; 1985:83-90. 

%r :\als, . A. C;. , C:. k,. ~or~:eIl., ana L. L. 

kff eltranger. ht~rsery appllcatlon of Lenon'yl 

tungici.de for f iel CI coirrrol of. brown-spot 

needle blicrht (Sci rrhi ;i ~cicol a (bearn. ) .., - --- - - - - - - - - - Siggers .) on 1nn.ql pal- !.ice (Pinus palustris --- --- ~~ill.). Tree PJ ant ecs' Isc3tcs 37(1) : 5; 1486b. 

Kais, A. G, and J. t, t:arnett. Longleaf pine 

growth following storage and benomy1 root-dip 

treatn~ent, Tree Planters' tiotes 35(1) : 30-33; 

1984. 

hais, A. G.; (:. F . Corci~11, and C. L,. 

Affeltranger. kertomyl root treatment 

controls brown-spot disease on longleaf pine in 

the Southern United States. Forest Science 32: 

506-511; 1586~. 
P. P. Kormanik and J. L. ~uehl~' 

Abstract.--Cornonly used standards for determining the quality 

of tree seedlings for reforestation do not appear to be good 

indicators of seedling performance after outplanting. The . number of strong lateral roots on a lifted seedling may be an 

improved indicator. In sweetgum plantings there is strong 

evidence supporting numbers of strong first-order lateral 

roots as a grading factor. The percentage of a mother tree's 

offspring that satisfy this grading criterion appears to be 

genetically controlled. Frequency distributions for other 

species indicate a similar situation. 

INTRODUCTION 

In this paper we describe a possible new 

criterion for grading of nursery seedlings for 

reforestation - the number of first-order lateral 

roots. Research on the relationship between the 

number of such roots on a lifted nursery seedling 

and survival and growth after outplanting is far 

from complete. At this point, however, we are 

reasonably certain this criterion will be valuable 

in grading sweetgum (Liquidambar styractflua L.) 

seedlings, and we have reason to believe that it 

will be helpful with other species. This paper 

outlines some of the evidence that supports the 

notion of determining seedling quality in part 

by counting first-order lateral roots. First, 

however, it presents some evidence that existing 

grading systems need improvement. 

As the popularity of seedling planting for 

reforestation has increased, the terms "seedling 

quality" and "quality seedlings" have appeared 

with greater frequency in the scientific literature, Starting with Wakeley's (1954) groundwork 

on seedling quality, much research has been done 

on seedling physiology and morphology as they 

relate to field performance. Nevertheless, recognizing and defining quality in planting stock 

is a major issue in forestry today and may be the 

major cause sf regeneration failure in both conifer 

and hardwood plantations (SIFRC 1984). 

For example, Johnson (1984) reported that 

after northern red oak (Quercus mbra L.) seedlings 

were culled at lifting, fewer than 40 percent were 

competitive 7 years after outplanting. Boyer and 

South (1986) recently reported that high mortality 

is common in southern pine plantations. It is 

now common practice to overplant loblolly pine 

l/paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

(Pinus taeda L.) seedlings by 30 percent or more 

in anticipation of high mortality. Boyer and 

South also found that over 50 percent of the 

southern forest tree nurseries they sampled produced fewer than 5 percent grade 1 seedlings based 

on Wakeley's morphological standards. 

Although silviculturists and nurserymen often 

disagree on the definition of seedling quality, 

most agree that stock must have enough height to 

get the top into the sunlight, enough stem diameter 

to support the top, and enough roots to supply the 

growing tree with water and nutrients (Bunting 

1980). Present nursery technology makes it possible to easily meet standards of height, root 

collar diameter, and root/shoot ratios, and even 

to influence root regeneration potential, nonstructural carbohydrate content, and mitotic index 

of stem apex (Cannell 1985, Duryea 1985, Duryea 

and Landis 1984, Feret and others 1984 and 1985, 

Kramer and Rose 1985). 

Why then do we still have problems in properly 

recognizing and defining quality in planting stock? 

One reason is that often each nursery sets its own 

standards. Even within a nursery, problems like 

bad weather cause the standards to be adjusted to 

meet production quotas. Another reason is procedural convenience. If seedling tops grow too 

tall, they are often mowed to better meet the 

size requirements of machinery used for spraying, 

lifting, and planting in the field. The bags used 

for packing and storing in certain nurseries will 

only accommodate seedlings of a certain size, so 

seedlings that are too large are damaged in packing. 

From a practical point of view, quality is fitness 

for purpose, and in the case of forest tree seedlings, fitness means survival and growth after 

outplanting. We need to develop standards that 

indicate survival and growth potential and can be 

understood and employed by nurserymen. 

A seedling's quality is difficult to define. 

Many believe that increasing the size of a seedling improves its quality. Wakeley (1954) stated 

~'Princi~al Silviculturist and Principal that seedlings with larger stems were not always 

Plant Pathologist, Southeastern Forest Experiment of the highest quality and he recognized that 

Station, U.S. Department of Agriculture, Forest physiology should be studied to determine potential 

Service, Athens, GA 30602 quality. Chlorophyll content and nitrogen content 
are useful for research purposes, but analyses of 

these factors in the operational nursery will 

probably never be used as a universal index of 

plant condition. Recent work on root regeneration 

potential shows it nay be a goad predictor of the 

best period to lift conifer seedlings from the 

nursery (Cannell 1985, Feret and others 1985, 

Kramer and Rose 1985, Stone 1955, Stone and 

Schubert 1959, Stone and others 1962 and 1963), 

but its suitability for detemining the quality 

of individual seedlings is questionable. A seedling might have a high root regeneration potential 

rating and still be below suitable size standards. 

Also, root regeneration potential is very difficult for most nurser3men to measure and there is 

little evidence to suggest this would be useful 

for hardwoods. 

What we need are seedling attributes that 

will correlate well with performance in the field. 

The attributes also should be rather easily measured by nursery personnel. 

RESEARCH OH SWEETGUM 

Based on the results of some earlier mycorrhizal research at the Institute for Mycorrhizal 

Research and Development w'e began to see the need 

for correlating individual seedling attributes 

- rather than groups of seedlings sharing broadly 

defined attributes in common -with field performance. In 1974 a major research initiative at 

the Institute was designed to improve morphological 

seedling quality of sweetgum seedlings using 

selected vesicular-arbuscular mycorrhizal (VAM) 

fungi and appropriate fertilizers in the nursery. 

At first we found that seedling size could be 

significantly improved in 80 to 90 percent of the 

seedlings by maintaining adequate levels of viable 

VAM inoculum and moderate levels (25 to 50 ppm) of 

available soil phosphorus (Kormanik and others 1977 

and 1981). Later we discovered that more than 90 

percent of the progeny from most half-sib mother 

trees exceeded the seedling size minimum (0.6 to 

0.9 cm root-collar diameter and >0.6 m stem height) 

when available soil P waqmaintained at high levels 

(75 to 150 ppm) regardless of Vk"! inoculum levels 

(Kormanik 1985). 

When these seedlings of uniform size, all 

above the size minimurn, were outplanted, some 

individuals grew rapidly and expressed dominance 

after 5 years while others grew poorly. When roots 

were excavated during the first growing season and 

assessed for mycorrhizal development, growth differences between individual seedlings could not be 

attributed to differences in mycorrhizal or other 

nursery treatments (Kormanik 1985). These assays 

showed that the roots of all seedlings throughout 

the plantations were well colonized by indigenous 

VAM fungi several months after planting. However, 

additional root excavations in subsequent years 

indicated a positive correlation between growth 

performance and number of first-order lateral 

roots. These field observations did not allow us 

to separate cause from effect, but they suggested 

that the number of first-order lateral roots formed 

in the nursery might be a key to determining a 

seedling's quality. For this work, strong 

laterals in sweetgm were defined as roots that 

are suberized to some degree, are larger than 

1 m in diameter at the proximal end, and occur 

within 15 to 25 em of the root collar. 

Research was initiated to determine if nursery 

practices had an effect on the frequency of these 

lateral roots. Studies were conducted for several 

years at the Whitehall microplot nursery in Athens 

employing combinations of cultural procedures, 

fertility, and symbiont inoculation. Over a 3-year 

period thousands of seedlings were grown under many 

treatment combinations; a few combinations resulted 

in 80 to 90 percent of the seedlings from any halfsib seedlot exceeding the minimum size standards 

mentioned above. However, regardless of treatment 

combination or seedling size, the numbers of seedlings in first-order lateral root classes was 

comparable. The frequency distribution of seedlings rated on number of first-order lateral roots 

remained rather cpnstant within each seedlot, 

regardless of nursery treatment, with from 30 to 

50 percent, depending on seedlot, having fewer 

than four strong, first-order lateral roots. Previous field data showed that seedlings in this 

root category survived and grew poorly. We then 

assessed seedlings from both state and industrial 

nurseries using other seed sources and found 

similar frequency distributions. It appeared to 

us that this root characteristic was under genetic 

and not cultural control. Kormanik and Muse (1986) 

proposed that regardless of the phenotypic characteristics of a mother tree, seedlings from this 

tree will exhibit a range in the frequency distribution of first-order lateral roots. They further 

suggested that seedlings with less than four 

strong, first-order lateral roots will be significantly less competitive in a plantation. 

Seedlings from recent nursery studies involving the above mentioned treatment combinations 

were lifted, individually assessed, and outplanted 

on an upland site near Aiken, South Carolina. 

Early field results have been reported by Kormanik 

(1986). The 5,000 planted seedlings were grown 

under a wide range of fertility regimes, with or 

without mycorrhizae. Approximately 50 percent had 

less than four strong, first-order lateral roots. 

Seedlings were planted at 3.3 x 3.3 m spacing and 

each subplot contained trees with similar root 

morphology. 

After 1 year in the field, nursery treatments 

had Little influence on survival and growth. 

However, in spite of a record drought during this 

year, 80 percent of the seedlings within each 

subplot with more than six strong, first-order 

Lateral roots survived. During the fourth growing 

season, seedlings in these subplots were clearly 

superior. Their crowns had closed and were more 

than twice as large as surviving seedlings on 

subplots established from seedlings with less than 

four first-order lateral roots. 

This work with sweetgum strongly suggests 

that field performance can be greatly improved by 

planting only seedlings exceeding the minimum 

aboveground standards and having more than five 

strong, first-order lateral roots. If such 
standards are employed, from 30 to 40 percent of 

the annual crop in most nurseries will have to be 

culled. Although our field data only covers 4 

years of growth, if these early growth differences 

continue for another 3 to 6 years, the expense of 

culling should be easily justified. 

Since results with sweetgum research were so 

promising, we decided to examine seedlings of 

other important forest trees. We used the same 

standards for rating strong, first-order lateral 

roots realizing that the 1 mm diameter minimum 

might be inappropriate for other tree species. 

This lower limit may be too low for walnut and 

oak and may be too large for southern pines. 

Future research on outplanting performance should 

provide the appropriate adjustments for these 

other species. 

OBSERVATIONS ON OTHER SPECIES 

In addition to sweetgum we have estimates of 

first-order lateral root counts on walnut (JugZans 

nigra L.), northern red oak, green ash (Frminus 

pennsyzvaniea Marsh), loblolly, and longleaf 

(Pinus pazustris Mill.) pines (Table 1). Although 

we realize that extensive research is needed 

before a seedling's quality can be defined for each 

of these species, we saw some interesting relationships after making these assessments. By combining 

minimum seedling size and counts of lateral roots 

we estimated that more than 60 percent of the 

walnut and northern red oak should be culled. This 

is in agreement with the results reported by Johnson (1984) from a 7-year field study with northern 

red oak. 

In our nursery studies on pine and oak, fertilization adjustments to make seedlings larger 

had little effect on numbers of strong, firstorder lateral roots. However, if seedlings were 

grown at high seedbed densities, it became difficult to identify strong, first-order lateral roots. 

As seedbed density increased the first-order 

laterals tended to be smaller in diameter and had 

less secondary thickening. We feel that this 

response is directly related to the fact that less 

photosynthetic capacity is exposed to optimal light 

intensity at these higher densities. 

If, as we suspect, a seedling's development 

of strong, first-order lateral roots is under 

strong genetic control, then nursery practices 

should be adjusted to permit this trait to be fully 

Table 1.--Frequency distribution of seedlings having strong, first-order lateral 

roots exceeding 1 mm in diameter at proximal end 

Number of 

first-order 

lateral Northern Green Loblolly Longleaf 

roots Sweetgum Walnut redoak ash pine pine 

Total No. 

seedlings 3840 379 746 377 2010 1433 
expressed. This is particularly important if 

seedlings are to be culled at lifting for 1-0 

stack, or before lining out in the case of 1-1. 

If nursery personnel, in addition to assessing 

height and stem diaaeter, must identify strong, 

first-order Lateral roots, the roots should be 

fully developed to maximum size and show secondary 

thickening. 

CONCLUSION 

Extensive nursery and field research will be 

required to deternine the appropriate combination 

of stem and root characteristics for each individual tree species because growth and development 

of seedlings varies by species, nursery location 

and environmental conditions. Each species tested 

may require different combinations of height, stern 

diameter and number of strong, first-order lateral 

roots to define a seedling's quality. Our experience during the past 8 years in nursery experiments with sweetgum, oak, walnut, and pine seedlings found that with selected nursery treatments, 

there were often many seedlings with large stems 

and few strong, first-order lateral roots, and 

with other treatments, there were many seedlings 

with short, spindly' stems also with few laterals. 

But we have never observed seedlings in any 

treatment with many strong, first-order lateral 

roots and short, spindly stems. 

We have found, within a reasonable range of 

nursery conditions, lateral root development 

remains rather stable. We suggest that because 

of the predictable frequency distribution of pine 

and hardwood seedlings derived from counts of 

strong, first-order lateral roots within half-sib 

progeny, lateral root morphology should provide 

a biological basis for assessing a seedling's 

quality. 

LITERATURE CITED 

Boyer, James E.; South, David B. Loblolly pine 

seedling morpholygy and production at 53 

southern forest nurseries. Auburn Univ. 

Southern Forest Nursery Management Cooperative. 

Publ. 28; 1986. 8 pp. 

Bunting, W.R. Seedling quality: Growth and development - soil relationship, seedling growth and 

development, density control relationships. In: 

Proc. N. Am. forest tree nursery soils workshop; 

1980 July 28-August 1; Syracuse, KY. 1980:21-42. 

Cannell, Melvin G.R. Physiology of southern pine 

seedlings. in: South, David B., ed. Proc. 

International S:mp. on nursery management 

practices for the southern pines; 1985 August 

4-9; Montgomery, AL. Auburn, AL;1985:251-274. 

Duryea, Mary L., ed. Evaluating seedling quality: 

principles, procedures, and predictive abilities 

of major tests. Corvallis: Oregon State Cniv.; 

1985. 143 pp. 

Duryea, Xary L.; Landis, Thomas D., eds. Forest 

nursery manual: Production of bareroot seedlings. 

The Hague: Martinus SijhofflDr, W. Junk Publ.; 

1984. 

Feret, Peter P.; Freyman, Robert C.; Kreh, Richard 

E. Variation in root growth potential of loblolly pine from seven nurseries. In: South, 

David B., ed. Proc. International Symp. on 

nursery management practices for the southern 

pines; 1985 August 4-9; Sontgomery, AL. Auburn, 

AL; 1985 : 31 7-328. 

Feret, Peter P.; Kreh, Richard.; DeWald, Laura E. 

Root growth potential of stored loblolly pine 

seedlings. In: Shoulders, Eugene, ed. Proc. 

third biennial southern silvicultural research 

conference; 198A November 7-8; Atlanta, GA. 

Gen. Tech. Rep. SO-54. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

southern-Forest Experiment Station; 1985:18--24. 

Johnson, Paul S. Responses of planted northern red 

oak to three overstory treatments. Canadian 

Journal of Forest Research 14(4):536-542; 1984. 

Kormanik, Paul P. Development of vesiculararbuscular mycorrhizae in a young sweetgum 

plantation. Canadian Journal of Forest Research 

15:1061-1064; 1985. 

Kormanik, P.P.; Muse, H.D. Lateral roots a potential indicator of nursery seedling quality. In: 

TAPPI Proc., 1986 Research and Development Conf.; 

September 28-October 1; Raleigh, NC. Atlanta, 

GA; 1986:187-190. 

Kormanik, Paul P, Lateral root morphology as an 

expression of sweetgum seedling quality. Forest 

Science 32(3):595-604; 1986. 

Kormanik, Paul P. Can lateral root characteristics 

be a major factor in assessing seedling quality? 

In: Schmidtling, R.C.; Griggs, M.M., eds, Proc. 

18th southern forest tree improvement conf.; 

1985 May 21-23; Long Beach, MS. Sponsored publ. 

No. 40. Gulf Port, MS. 1985:290-297. 

Kormanik, Paul P.; Bryan, William C.; Schultz, 

Richard C. Effects of three vesicular-arbuscular 

mycorrhizal fungi on sweetgum seedlings from 

nine mother trees. Forest Science 27(2):327-335; 

1981. 

Kormanik, Paul P.; Bryan, William C.; Schultz, 

Richard C. Quality hardwood seedlings require 

early mycorrhizal development in nursery beds. 

In: Proc. 14th southern forest tree improvement 

conf.; 1977 June; Gainesviile, FL: 1977:289-293. 

Kramer, Paul J.; Rose, Robert W., Jr. Physiological 

characteristics of loblolly pine seedlings in 

relation to field performance. In: South, David 

B., ed. Proc. International symp. on nursery 

managment practices for the southern pines; 1985 

August 4-9; Montgomery, AL. Auburn, AL; 1985: 

416-440. 
Southern Industrial Forestry Research Council. 

American Pulpwood Association, Inc. and Southern 

Forest Products Association. Southern Indiana 

Forest Research Council Rep. 3; 1984. 15 pp. 

Stone, Edward C.; Schubert, Gilbert H.; Bensler, 

Rolf W.; Baron, Frank J.; Krugman, Stanley L. 

Variation in the root regeneration potentials 

oE ponderosa pine from four California nurseries. 

Forest Science 9(2):237-225; 1963. 

Stone, Edward C.; Jenkinson, James L.; Krugman, 

Stanley L. Root-regenerating potential of 

Douglas-fir seedlings lifted at different times 

of the year. Forest Science 8(3):288-297; 1962. 

Stone, Edward C.; Schubert, Gilbert H. Root regeneration by ponderosa pine seedlings lifted at 

different times of the year. Forest Science 5 

(4) :322-332; 1959. 

Stone, Edward C. Poor survival and the physiological condition of planting stock. Forest 

Science 1(2):90-94; 1955. 

Uakelep, Philip C. Planting the southern pines. 

Agriculture Monograph 80. 18. U.S. Department 

of Agriculture, Forest Service; 1954. 233 pp. 
By Robert 6. Fr and Peter P. pereta 

Abstract- The 15 day hydroponic system has proven to be a shple, 

sive, and relatively fast method for masuring root growth potential 

This paper dscr&es various melssurs of KP, It appas that 

while new root length is a better predictor of field growh prformance 

than new root nurrber, correlations between new root number and growth 

t can be Pnade "to =roach those of rout Pacjth by using only n of long roots. Compared to new root n&er or lqth, mrcent sedlings 

producing 1 or mre new roots is better eorrelatd with survival. Data are presented for smle sizes to estimate a prticular miur at. precision 

levels of t- lo%, t 20'4, and 2 30'8, 

I ION 

me realization that a seedlhg should be 

evaluatd by mre than mr@logical criteria 

has generated interest in measurbg seedling 

physiological quality. Root growth potential 

(RBI, defined as the ability of a tree seedling 

to quickly produce and elongate nkw roots in an 

enviromt favorable for root growth, is being 

used as an indicator of seedling quality. l%?z 

maybe one of the mre reliable predictors of 

field perf ormce (Ritchie, 1985) . have control over seedling 

mrphology through the application of cultural 

practices such as sizing sed, swing rate, 

irrigation, fertilization, top pruning, 

under-utthg and wrenching, Cultural practices 

also affect the quality of the crop prducedii. 

Morphological grades may indicate seedling 

quality but: within a given mrphological grade, 

physiologic& quality can vary greatly 

and the relationship between and seedling 

size has been shown to be weak. Feret and Kr& 

(1985) found no relationship between loblolly 

pine seedling RL;P and root collar diameter and 

Feret et al. (1985a) found less than twenty. 

percent sf 128 seedling samples sbwing a relationship between RGP and loblolly pine 

~eedling~height, root collar diameter, volume 

index (I) x HI, or height/diirmeter. Larsen and 

Boyer (19851 found some relationship betwen ~$2 

------ 

"~aper presented at Southern Silviculture 

Research Gonference, Atlanta, Georgia, I1Jovder 

4-6, 86. 

'Research Specialist, and Associate 

Professor, Dept. of Forestry, Virginia 

Polytechnic Institute and State University, 

Blacksburg, VA 24061, 

and seedling mrphology in a study of seedlings 

from twenty nurseries, but concluded that "a 

significmt and prob&ly greater degree of 

variation in EP cara aist mng seedlings of 

similar mrpkolw, * 

While nursermm have control over seedling 

mrpholw, they can &so control factors 

affecting physiological quality but not 

morphol~; these factors hclude seed source (fitchie, 1985; MU, et &I, 1985b1, time of 

lift (BWaLd, 1986; F and Feret, 1986; 

Feret et al,, %985a) Id storage condition 

and duration (mrdm me7 Feret, 1986; Dad, 

on, 1985; Feret et dl., 198%). 

who routhely check the size, form, 

and cvlor of their crop during the growing semon sMuld also consider checking the 

physiolqica condition of their crop during the 

lifting season, and after handling and storage. 

The Liftbg season is an extrmely busy period 

during the nursery year. Any method for 

rnonitorw seedling quality changes must be easy 

and inagensive. The usual IGP test involves 

placing seedlings in a soil medium and after a three to four week period rmving the seedlings 

and evieluating RZP in 

(2985) der;cr&& the 

ives, and RGP testing in general. There 

disadgswtages to the four week soil 

testing systm, These disadvantages and an dternative hydrownic system have been 

descr*ed by Dm163 et al. (1385a) . The 

hydroponic systm is easy and inexpensive to 

build md opmrate. The hydroponic system also 

prduees mresults wivalent to those of the soil 

systm but in a slrcsrter tirne period (IIeFald et 

ale, 1985a), (Ritchie, 1985 also presented 

results shQwing good correlation between a hydropsnic system and a soil system,) Briefly, the hydrownic system consists of placing 
seedlings in aeratsd 37.8 liter (10 gallon1 

qarim for a full 15 days after which 

stsedf-s are f~llduated far XZ, 

r fur*er dwcr&w the use of the 

systern prsated by Maid et al., 

1985a, tfiose tiGP m.Elsur.es which m@e of mst 

interest, the natur 

of vari&ility that 

wropriate sm1e 

%ugh the hydroponic system provides XI? 

results cheamr and quicker than the soil 

system, RZ;P measurement is still mre involved 

just taking rmrphological masures. A 

of data is showing that FCGP is a 

good indicator of loblolly pine field 

is worth the trouble to masure. The correlations in table 1 show the significant 

relationship between El? and loblolly pine first 

year surviva9 and growth, especially for those 

sqles planted in the spring when aditions 

allow expression of IUZ. Significant 

correlations between FGP as number of new roots 

and loblolly pine seedling field performance 

have also been shorn by Feret and Kreh (1985) 

(-63 and .69 for first year survival and height 

hcrment for 31 sanple mans), Feret et al. 

for first yea survival 

using 44 sqie mans) , 

Mafd et ale (198%) (0.76 for first year 

heig using 15 sqle means, survival 

was 9%), and Barden (1986) (0.52 

md st year suwival and height 

incr 50 smle mans). 

Rzitchie (1985) described various measures of 

ting the nunt3er of roots, 

h of the new roots, using 

difference of the root system 

he test, and weighing the new 

roots. O£ the above methods, mting and 

masuring length the new roots are and need no special 

sess the new root system 

into short roots (those that are greater than 0.5 m but less than 1.5 ad, 

ilnd long roots (those that are greater than 1.5 

un in lwth), RB is calculated as either: 

1, n&er of new roots = nunber of shorts + 

rider of lorag roots. or: 

2, length of new root umber of shorts + 

length of long roots. ( r of short roots = length of short roots because short roots are essentially 1 m in length,) In general, field 

performance is better correlated with length of new roots as compared with nunber of new roots, 

but meczr;urinq the length of the new roots can be a very tdious and time consuming process. 

Counting the nunber of new roots is faster and 

easier, Because the only difference between 

nunber of new roots and length of new roots is 

in either counting the long roots or measuring 

the long roots, the relationship between length 

of long roots Efnd rimer of long roots was determined. 

Table 1. Loblolly pine seedling root growth potential - field performance 

correlation ooefficients for all samples and spring lifted 

sanqples 

1st yr 2nd yr 3rd yr 1st & 2nd yr 3rd yr 

number of new roots 0.39"" 0.16 0.15 0.40** 0.21 

length of 

newrosts 0,30* 0,ll 0.15 0.42** 0.30* 

length of 

nwrmts 0.66"" 0,33 -0.12 0,52* 0.16 

1, Data from an urrpublished root growth ptential genetics experiment of 

Fer&, POP, and R,E, Kreh, Dept, of Forestry, Virghia Polytechnic and 

State miversity, Blackburg, VA. * Siqifimt at the .05 Level. 

** Siqnificmt at the .01 level. 
total length long roots = 1.87 + 4.31 nJo basic criteria evaluate field performance, 

rider of long roots the first being survival and the second being 

2 growth. Height and basal area growth data in 

n==4741 r = .77 table 2 show that sample means of new root 

length correlate better than do means of nurrber 

The above equation (based on seedlings from the of new roots, and wch better than median nurrSrrer 

soil system) indicates that a weighted count, of new roots, Weighting the number of long roots 

i .e, weighting the rimer of long roots by a however, produces correlations approaching those 

factor of about 4 and adding that to the nta-t-ixr produced with root length. Weightings of 4 or 

of short roots should produce a quantity 10 (ie. total nu&er = nunher of shorts + 

equivalent to new root length. number of longs * 4) produce correlations with 

growth increment equivalent to those of root 

fn order to determine if correlations between length. This indlicates that the long roots are 

field performance and n&er of roots could be more important than the short roots in 

inproved, field data from a 1983 outplanting contributing to the association between n-r 

established on an old field on the Virginia of new roots and growth incranent. In fact 

Piedmont were reinvestigated. These data are correlations between growth increment and just 

presented in table 2. First, one should note number of long roots are better than total 

that RGP, however it is measured or transformed, number of roots and as good as length of roots. 

is closely correlated with first year and 

second year field performance. RGP is expected Average nu&er and length of new roots 

to be correlated with first year field produce slightly lower corrrelations with 

performance, but it is interesting that second survival as 06r?pared with growth. This can be 

year growth is also indicated by RB. The data noted in table 1 and 2 and the correlations 

in table 1 also show significant second year cited above. If the RB sqle is wakyated 

performance correlations (for spring planted by using the percentage of the seedlings 

seedlings) but the correlations are weaker in a sample producing one or more new compared to the first year correlations, Third roots, better correlations can be obtained. For 

year increment is not correlated at all with exqle a correlation of 0.64 is obtained 

planting time RC;P (table 1). between first year survival and the percentage 

Table 2. loblolly pine seedling rTt growth potential - field performnee 

correlation coefficients. Comparison of IEGP measures. 

1st yr2 2nd yr 1st yr3 2nd,yr 1st yr 2nd yr 

llLiDGLht;..insz.~~~~ 

MEAN new root LEXTH 0.55 

MEAN new root NUMF3ES 0-50 0.51 0.53 0.55 0.48 0.48 

MErlDIAN new root NUMBER 0.42 0.46 0.46 0.48 0.42 0.42 

NUMBER 

(long only) 0.53 0.55 0.57 0.61 0.44 0.45 

mp1% 2 l5 

new roots 0.46 0.51 0.49 0.52 0.64 0.62 

1. Cohined data from outplantings associatd with experiments reported 

by Feret et al. (1985a) and Feret et al. (1985b). n=56 for first year 

growth increment, n=54 for second year growth increnent, n42 for 

survival. All correlations are significant at the 0.05 level. 

2. Height increment. 

3. Basal area increment. 

4. Mean nurnber of roots, n-er of long roots weighted as indicated 

and added to short roots. 

5. Percent of the RC9 sarrple which produced greater than or equal to one 

new root. 
of the seedling producing 1 or more new 

roots (that is, EUYY new root growth at 

all) coqpred to a 0 -48 correlation with nurrber 

of new roots. 

The above indicates that lli(;P is related differently to survival as ed to growth. 

is conplted on all seedlings, while 

8 cqyted only on living seedlings. 

Survival and growth are also different 

quantities, in that survival is qualitative 

measure, while growth is quantitative. In order 

for a seedling to survive it needs a minimrm of 

whatever attributes are critical for the 

seedling in the planting situation presented. If the seedling possesses the needed attributes 

in proper measure, it will survive, with no way 

0 

-T-- ---r-- - r - 

10 20 30 

NUMBER OF NEW ROOTS o 

80 

0 

0 0 

0 L - ---- - - . T-- - 1 

0 10 20 4J 40 

NUMBER OF NEW ROOTS 

"1 0 0 

0 

0 

r - -7 - 9 - - -.- 1 -1 

.2 .I .6 .8 1 

PERCENT GOOD SEEDLINGS 

,C, - -,-------..---,- -- ---- 7- -1 

0 10 20 30 40 

NUMBER OF NEW ROOTS 

Figure 1. Relationship between loblolly pine 

field performance and root growth 

potential as ntmiser of new roots 

or percent good seedlings 
at lowers EfZ a greater proportion of a swle is 

covsed of sdlhgs that do not possess the 

needed attributes in proper masure for 

survival, and while poor survivaZ may not dmys 

occur, greater variability in survival. can be 

wpected, Clnce a suithle RB is attained there 

is little increase in survival. It 

the correlation coefficients in tab1 

percent of the smle producing at least one or 

mre new roots is the best indicator of the 

proprtion of the seedling lot Flhicb will have 

ributes in proper masure to 

t any given sample a 

seedlings will survive, but 

these suwivw sdlings will mst likely sbw 

growth in direct proprtion to the average 

of the sample. Therefore, two msures of ECZ 

are of interest, the first being the percentage 

of seedlings in a sample prducing at least some 

new roots (being the best indicator of 

surviva), and second, the average rider of new 

roots (hdicathg the ted growtrh relative 

to that of other samples) . ern SIZES 

If is to be used to monitor the changes 

that mur in a seedling crop during the lifting 

season mUor cold storage, an appropriate 

sample size mst be taken to determine I42 with 

a certain precision and confidence. Before 

hg sample size a few comts about the 

data are need&, The following discussion is 

wncernd with individual trees as replications. 

In the hydropnic system seedlings frop any 

given sample are placed in mf-e than one tank. 

These tcanks are considered the replication. 

It has been our rience that tank does not 

&feet RGI", Even if tank in the hydroponic syssystesn did affect RGP, the amount of variation 

would have to be fairly large to consider it in 

any analysis. The loss in efficiency of going 

f roan single tree rqlication 'to tank replication 

wuld mst likely out-eigh any reduction in 

variance by including tank in the del. 

Ushg rimer of new roots as the measure of 

FKZ provides count-type data. This type of data 

is ly distributed. Taking 

th individual seedling 

&sewations usually normalizes the data nicely. 

ysis should be preformed on 

Figure 2 shows the typical variation that is 

eaacountered with the hjdropnic system. Two 

thhgs are of in"eeret to note in the figure. 

First, the x-=is show the typical. range in 

6-1e averqs for nwer of new roots after 

the 15 day hydroponic test, Second, the trend 

in csefficient of variation is seen to stabilize 

in sqles with averag- greater than about 2 

new roots. At very low sqle averages the eVts 

are very high due to the large n~er of seedlings with zero IIGP, Average CV in samples 

that haw averages greater than 2 new roots is 

85% in the raw form arxl 55% after trrulsfomtion 

by square root. 

O& t i 1 1 

0 5 10 15 20 

NUMBER OF NEW ROOTS 

Figure 2. Relationship between coefficient of 

variation and root growth potential 

as number of new roots for loblolly 

pine seedlings from the hydroponic 

systsn. 

There are two different situations in which 

sample size is important. First, one my want to 

determine with precision and coniidence a particular mean RQ?, or, one may want to detemhe if 

two sanq,1e mem are different, Wn example of 

the first situation wuld be a nurse 

toring the RGP changes that occur o 

season. At. any particular period the average 

of the seedling crop would need to be =tiwith a certain precision (ie. + 20%) at a 

particular confidence level (perhaps 95% confidence) . As an example of the second situation, 

a nurseryman may desire to how if the ECZ is 

statistically different between tw areas of the 

nursery, or perhaps between two mnths during 

the lifting season. In this situation he would 

need to know the particular sample size needed 

to differentiate two means that are, perhaps 30% 

or more different, 80% of the time at the 0.05% 

significance level. m the first case sample 

size calculations need to be bas 

data, In the second case trans 

should be used, 

Sample sizes for the first situation 

g a particular sample meal for 

and soil systenns were det 

two ways. First, swIe size was estiTnat& frorn 

each sqle with an average of 2 2 new roots 

(these were mnsiderd to have "stablen CV%s). 

There were 172 and 157 sarrfples that had sample 

means of at least 2 new roots in the hydroponic 

and soil systms respectively (table 3). The 

sample sizes that were estimted frorn each of 

these individual sarples were averaged to give 

an overall estimted sample size for three 

precision levels a l l a t 95% co&idence. 
Table 3. &timated swle sizes for the 

hydroponic and sail RGP sl"z;.tcrras using 

irrdividaaa RGP saqles for stktion 

1 sqls had Ra? 

2 2 nw rwkSf or, ushg one 

powlation of seedlhgs - mtM 2. 

(Elsthted at 95% codidace levelf . 

Soil 

( 1) 157 10,513 524 13% 58 

Soil 

2) 5830 8,9 747 384 83 

1. Nuxrber of sqles (for 

seedlings (for mtM 2) from which 

sample sizes were calculatd, 

2. Mean n&er of new roots of the 

saiqles used to atimte smle size. 

3. Estimated sample size at &ee levels 

of precision using raw data, 

size was also estimated by plaehg all seedlings 

from all sqles into one Large pplation. 

There were 8827 and 5838 sdlhgs in the 

wropnic and soil pwlations rsptively, 

Table 3 presents the =timat& sqle sizes 

needed for three precision levels at 95% 

confidence. In generd sthtd sample sizes 

are smaller for the hydropic systan as opposed 

to the soil systm md sqles estirnatd by the 

second method are Larger than. the first method. 

Two factors need to be balmed in deciding on 

sample size, level of pre~ision and practical 

sample size. Ta be withh + 10% a simple of 300 

to 600 seedlings would be need&. That is too 

large. If one considers a sarnple of 45-60 

seedlings as manageable, then one can expect a 

range of about 30% of the sqle mean will 

include the true mean 95% of the tine. 

le size estimation in the s tuation 

ennining the difference bet mans 

s in part on the nwer of ts in 

e analysis (or the nunrber sf dqres 

freedom for error est-tian), the desirfd 

probability of being correct (the power of the 

test) and the signif icmce 

statistical test. Transfo 

used in order to fulfill the aslsqtiom of the 

test and to make the test mse sensitive. Table 

4 presents an exqle approx-ting a typical 

situation, It ears; that with a sample size of 

45-60 seedlings, a differace sf about 30% 

between two means will be detectd 80% of the 

time at the 0.05 signif ieance level (conpard to 

a 50% difference in the raw data). 

e size, G\f= coefficimt of variakion, 

% differmce = percat diffeswce between twrt 

mans, l? = dwired pr&abiLity that a 

differmce will be fsuand, t = values from two 

tailed t-table. (Skalf. and mME, 1981) 

assume P= 80% pr&abiliky of behg rxtrrect at 

0.05 level of simificmce using Mjnite t 

values 4 

The above discussion is center4 on estimating 

the average number of new rsots. mtimting the 

percentage of a sqle which prduces new roots 

will take larger sqle sizes (=timated at 

about 300-500 sedlings to be within + 30%)- 

However evaluating the n~er of sdlings which 

show some W or no EX2 will be very rapid and 

if ninety seedlings are place in one tank, only 

six tanks will be ndd, 

The fifteen day hydrclponic test (as described 

by DeWald et al,, 1985al is a cheapr, faster, 

and simpler alternative to the standard soil 

system for evdlclating W4 ?Am measures are of 

prhry interest, the first being the average 

nunber of new roots which is the best indicator 

of growth in the field, and the sand being the 

percentage of the seedlbg sqle hich produce 

at least 1 new root which best indicates field 

survival. Sample sizes of 45-60 seedlings, 

using individual seedlings as rqlication, will 

provide precision of ;.about + 30% and delineate 

twa mans that are aut 30% different in the 

scale using the square root 

trwf omation, 
1, Bardw, C,E6, 1986, Wlolly pine root 

regeneration ptatid in sdlbgs from two 

nurseries ;and its relationship to field 

e,, IVister Thesis, Bept of Foretry, 

Virginia Polfiwhic md State Univ,, 

Blacksburg, VA 24061, 

2, Brda, C,E. md PSI?, Feret, 1986, Roo%. 

gro~h potatial of loblolay pine sdfhgs held 

in cold storwe mder differhg mishre 

ts, Prsc, 1986 SE N~rse 

Gonf., Pmsacola, Florida,, in press, 

3, Reh&e, W,F., artd T,O, Per=, 1965. 

Genetic variation in ability to witktand 

trwplmthg shock, ;hg Proc, Eighth South. Con, 

on For, Tree Imp,, Savm&, GA,pp 106-189. 

4. Burdett, A*Nsy B.G. S-son, and G.F. 

Thowon. 1983, Rmt. devel and plmtation 

Soil 

71:103-110, 

5. Cizrlson, W.G, 1985, Effects of natural 

chilling and cold storage on bu&reak and root 

growth ptatial of lobfolly pine ( 

L,) Can. J, Far. Res, 15':651456. 

6. Maid, L,E., P,P, Feret, andt R.E. Kreh, 

1985a. A 15 day hydrownic system for mrasuring 

root growth ~tmtial. Proc, Third ~iennial 

Southern Sil, Res. Con,, Gm Twh. Rep, W54 

USM-USPS Sutbern For. JBp, Sta. pp 4-10, 

7. DeWald, L.E., Pea?, Feret, andR,E. Kreh. 

1985b. metic variation in loblolly pine root 

growth potatid, & Proc, 18th Suthern For, 

Tree Imp. Con. pp 155-262, 

8. Wald, L.E. 1986, Changes in loblolly pine 

seedling root guo*h ~tmtid over time, during 

cold storage, and ana=lw h&f-s& farmilie, PhD 

dissertation, Bpt, of Foretry, Virghia 

Polytechnic and State Univ., Blacksburg, VA 

24061, 

9. Feret! P.P., R.C.Fr i3nd R.E, Kreh, 

1985a. Variation in root 

loblolly pine from sevgn nurseri 

joint IWM -urn Wiv, Bte~n, 

Pines. Aug, 1985, Wntgomq, AL, pp 317-328. 

10. Feret,P,P, R.E. Kr&, and L,E. DeFJald. 

1985b. Wt growth pitatid of stored loblolly 

pine se&lings, & Proc6 %hir&l ~iennial Southern 

Sil. Res, W,, Gen Tech. Rep, -54 Um+SS 

Souaern For, Ekp, Sta, pp 18-24, 

, ROC. cand P, P, Feret. 1986. 

Variation in I&lolly pine seedling root grow 

ptmtial over two lifting seaom. k Proc, 

1986 SE Nursermls Cbnfe, Pensamla, Florida,, 

in press. 

13, Larsen, B,S, am3 J.M. Boyer. 1985. Root 

gro~h potential of lobfolly pine ( 

L.1 seedlings from 

Aliibm mricultural Ekp, Sta,, Mum ~niv., 

Circular 286, 16 pp. 

14. Ritchie, GA. 1985, Root growth potential: 

Principles, proeeclur9s, and predictive ability, 

in: Duryea, M.L. ed. maluating seedling 

quality: principles, procedures, and predictive 

abilities of major tests. Forest Res. Lab. 

Oregon State Univ., Corvallis, OR. pp 93-105. 

15. SQkal, R.R. and F.J, BoN_f. 1981. Biomtry 

2nd dition, pp 262-264, 

11, Feret, P,P, and R.E. Mreh, 1985, SdShg 

root growth potential as an hdiator of 

loblolly pine field prfas 

31 (4) : 1005-1011. 
Charles J. Barden, Peter P. Feret, and Richard E. re# 

Wlol ly pine 1 seed1 inqs from 5 sersdlots 

(4 halfsib and a s f were raised at the Virginia 

Division of Forestry nursery at Provid e, Viqhria, and 

at the Wes Corporation nursery in Ile, auth 

Carolina. lings were lifted every from late Bctober 

1984 until mid-February 1985, and their rmt grorrlth potmt-i& 

IfM?) detennined. In &ition, sdlings were stored from the 

February lift and outplanted at 3 week hkenrals in the Virghia 

Pi&nt from early E-larch until late Elay 1985, IGP was 

determined on stored seedlings &es each plmtiw date, FGP 

varied by nursery, seedlot, and lift date, and a11 first-rder 

interactions were significant. First year sumival was 

significantly correlated with I.2@I>, 

The decreasing survival of planted 

loblolly pine &&g& L.) seedlings is a major concern in the South, In their survey 

wnducted from 1960 to 1978, Weaver et al. 

(1980) reported that pine plantation survival 

had decreased, while the acreage planted had 

nearly doubled. It has been estimated that 30% 

of planted seedlings die, and that much of this 

mortality is due to poor stock quality and 

inproper handing procedures (Venator 1981) . Since over 1 billion bareroot seedlings are planted yearly in the South (Boyer and South 

1984, Johnson et al. 19821, high mrtality 

regpresents a substantial loss. 

During routine lifting operations, a seedling 

typically loses 75% of its root mass (Nambiar 

1980). During operational root preaning to a 14 

an (5 1/29 taproot, the seedling's absorptive 

surface is further reduced. The size of a seedling's root system may not be critical. for 

growth in the nursery bed, due to being well 

supplied with water and nutrients in that 

environment (Nanbiar 1980). However, after 

being lifted and losing most of its roots, a seedling is planted in the field and subjected 

"paper presented at Southern 

Silviculture Research Conference, 

Atlanta, Georgia, Novder 4-6, 1986. 

2/~raduate Research Assistant, 

%prmt of Forestry, Pennsylvania State 

University, University Park, PA; Associate 

Professor, and Research Associate, 

respectively, Department of Forestry, Virginia 

Polytechic Institute and State University, 

Blacksburg, VA . 

to misture stress znd low levels of available 

nutrients, As a rsult, initial survival of 

outplanted seedlings depnds to a large extent on the aility of the injured root system to 

rapidly grow a~d ree?st&lish jntimate contact 

with the soil (Rozlowski and SGboltes 1948). 

Root groeh ptmtid (Wl is the ability 

of a seedlhg to regenerate its root system 

after planthg in a eontroll& environment. 

Stone (19553 develo@ the procsdure which has 

beeom the stmdard metw for WGIP 

tion. This procdure involves sampling 

sedlings, ravbg dany new white soots, pruning 

the trrprsots to a spifi& Zagth, and placung 

the sdlings in a con"&oll& environment for a 

set period of days. At the mnclusion of this 

period; the new root growth is yantified. 

RZP has been dmnstratd to be positively 

correlatd with survivd andlor field 

spp. (Feret et al, 1985a 

asnd b, Feret and Kreh 1985, Sutton 1980, Burdett 

1979, Stone and Morberg 1979, Jenkinson 1978, 

Rhea 1977, Stone 19551. In loblolly pine, as RGP 

levels increase, survival and first year height 

her-t also increae (Dmald et aP. k985b, 

Feret and Kreh 1985, Feret et ale 1985a =and b; 

1984), 

Plas bw succ~3~sful in assgsshg the onset 

qr and its relationship to 

Lifting dates, storqe effects, and field 

prfommce (Maid et al, 1985a, Feret et al. 

198%, Jdhson 1986, stone and JMkson 

1941). The qression of ,r-;tGP also has a strong 

gmetic @o~ner?Jtr, Wdd et ax. (1985b) and 

Carlson (19851 bth have sbw significant 

differmca in RiZ between h&f-sib loblolly 

pine families, 
r and Rose (1985) noted a through 

ion of seaond and genetic variation of 

sou~ern pine RGP was needed, and mncluded that 

progress towards mrovhg and stillldardizing 

s&lhg wality wuld be aca~lish& through a better understandin variation is 

related to sht do ldDs (19861 

recent work has pro ceded information 

in this area, F"urther work on the EtZ of 

sdlings will result in mre ipulation of seedling physioloqy, 

rwulting in sdliws with greater suwival and 

gror;ith ptmtial, 

With these amideratiom in mhd, the 

objwtives of this stuw were twofold: 

I, QumtiQ root growth potmtial changes 

during the lifting season over 2 nurseries rund 5 

seedlots (Expriment I) ; 

2. Determine the rela"&onship between RGP 

md subsequentoutfl 

after cold storage ( 

S& sources fix the study were 4 half-sib 

families arid a se& orchard mix, All seed lots 

originated from the 

source seed orchard 

Carol ha. 

Thirty seedlings were sqled at both 

nurseris from dl 5 s&lbts wproximtely 

every 2 weeks from early Mvder until 

mid-Feksruary, Weasionally lifting was postponed due to frozen ground in January or February, The roots were mistmed and the 

iately placed in plastic bags in a cooler with ice, The coolers were shipped to the 

Reynolds Homtead Research Center, in Critz, 

Virginia, to usldergo RGP analysis. 

Sedling W was detennhd using the system 

described elswhere (BeF7ald 1986, Feret et al. 

1985~). Mter 24 days the seedlings were rmv& 

from the trays, and root growth mesur&, me total length and total number of new long roots 

(>I ,5 and the total n~er of new short 

roots Q>B,5 m md (-1-5 d ere detemcined for 

each sdling* Sedlhg RGP was thus expressed 

as the total lqth or total rider of roots 

prczduced , 

CXI the final lift date of the semon (mid-F&ruary), an additional 3,300 seedlings were lift& from each nursery. &&lings were 

sorted ad pckag& into bundies of 33 seedlings 

~0n;fs~rstion The seedlhgs were pckaqd a"ceaeh nurserlg, placed in 

kraft-polyethylme bags, md trmsprtd to the 

MIF Charlottesville c~ld storage facility &ere 

they were stored at 2 C, 

?"be outplmting dates were every 3 weeks from 

early mrch until late May. On each date the 

sdlkgs were trans~rrtd to the site where 

they were rave63 from the K-P bags. For each 

block, Smily, nursery, and planting date 

combination 8 of the 33 sedlings ere randomly 

selected to iadergo RGP mafysis, The ra;anabing 

25 sdlhgs were pPmtd, The 8 seedlhgs were transported for araalysis "e the eepolds 

Center (Critz, W iately after planthg 

ws coqletec%, The outplmtbg site was on a Westvm W~ration tract locat& in Wc~inghm 

county on the Virginia Pi nt, The site had 

been olperrationdly karveted, and site prepared 

by drum-ebpphg md burnhg , 

taJ. Design md analysis 

t 1 and 11 were 3 treaclment 

ts, In the outplanting of 

Experiment 11, there were 4 

Analysis of dl data was per 

statistical mckage (W Ins 

6.1 , Using the maures of total length md 

cots, Malysis of Variance on the resuits to 

ts and hteractiom were a 

of s&lhg NP 

vari;lbilityl M alpha level of 0,Ol was us& 

for tests of skpificmce, 

Correlations were calculatd to dete 

degree of relation betwa FGP values at the 

time of planth~, and subsqent suuvivd and 

growh in the field, U.1 data were also 

sbdttt3d j70 Dmcm k New Hultiple Range Test to 

detemL3e where significmt differmces 

occurred, 

Pmt growth ptentiat was meaurd as the mean 

total lmgth and mew total nlirrber of new roots 

produced, Due to the very strong correlation 

fr=.93, p(,00lf betem rider and lqth, only 

nunber of roots will be discuss&, The KI? 

trend obsemd over the liftkg season was that 

of low vdues durhg the early lifts of late 

October and laveer, fslliow& by a suddetl peak 

on the 5th lift in late Beeder. values 

thm fell sharply, but rh~gldd with a smnd 

slightly lower peak on the 1st lift in 

mid-February (Figure 1) , *edlhgs from the 

mille nursery mhfiited higher KZ than 

s&lhgs from the Nw Kmt nursery on every 

lift date. 

reul%s indicated that all min effects 

(lift date, nurseq, md faxlily), and all first 
order interactions were highly significant 

(Wle 1) . The nursery x lift date interaction 

can be seen in Figure 1, Differences between 

nurseries were 1-s pronounced when RB levels 

were Mgh. The strong family x nursery and 

farnily x lift date intermions were due to 

highly variable family rankings by lift date. 

Family over the entire season ranked 

f dly ifth when raised at New Kent, while 

anked second wha it was grown at 

rville. EX2 values for each family peaked 

on the same lift (Sth), with the exception of 

6-20, which had a second equally high value on 

the 8th lift. 

Table 1. ANOVA table for number of new roots 

during the lifting season. 

F values are significant at 

p < 0.001. 

Source d f SS F 

lift date 7 16402.5 112.02 

nursery 1 88822.7 424.47 

family 4 17977.5 21.48 

nursery*f amily 4 13552.6 16.19 

nursery*lift 7 16673.4 11.38 

family*lift 28 15134.1 2.58 

error 2330 803821.8 

0 I I I I 

Lift Date 

lO/ZO 11/9 11/19 12/19 1/8 1/28 2/17 

Figure 1. Mean number of new roots by nursery for 

the 1984-1985 lifting season. Open box 

plot=New Kent, Closed box plot= 

Sumrnerville. 

The observed pattern, of low EM? values during 

the early lifts, and increasbg values into the 

winter agree well with previous reports (Feret 

et al. 1965a, Brissette and Roberts 5984, Rhea 

19771, with the excwim of the late 

peak, which occurred at bsth nurseriw. 

lifts were done after mid-February, hen 

EGP decline associated with the rapid r 

of shoot growth reported in other studi 

never observed in this study. 

The large, consistent differences between 

nurseries could be due to many factors. 

mrville seedlings had heavier lateral root 

ler-shoots, perhaps due to the 

undercutting and lateral root pruning practiced 

at this nursery. In loblolly pine abmst all of 

the new root growth observed in the RU? test 

originates on the lateral roots (DeWald 1986). 

NEo prolonged window of high EBGP levels was 

found, as has been reported for other species 

(Jenkinson 1984, Ritchie et al. 1985). FGP 

tended to increase and decrease sharply, with 

family rank changing markedly by lift date. 

This may have been sixriply sampling error, due to 

the small (30 seedling) samples for each family x nursery x lift date combination. If a mininium 

of 10 new roots is used as a threshold value, 

all seedlots (except 11-137 were ready to be 

lifted after late October at rville . However, at New Kent, no two consecutive lifts 

averaged over 10 new roots. 

RB declined sharply in storage from fresh 

lift levels (Figure 2). However, RB increased 

greatly on the fourth planting date, after 

approximately 12 weeks in cold storage. This 

resulted in the highest RU? values for New Kent 

seedlings, and the second highest values for 

Sumenrille seedlings over the entire storage 

duration, As no problems were noted at the 

Charlottesville storage facility, these RB 

changes in cold storage were not related to 

equipnent malfunction. me rapid decline of 

RB in storage was unexpected and unusual. 

Other reports have shown loblolly pine can 

maintain its aCP for at least 12 weeks in cold 

storage (Barden and Feret 1986, Feret et al. 

1985a) . Possible explanations for the decline in EGP 

are that the seedlings were stored too wet; 

this has recently been shown to reduce the RB 

of seedlings cold stored in R-P bags (Barden and 

Feret 1986). Many exqlm of poor storage 

success with early lifted s&lings have been 

reported (Ritchie 1984, Ritehie and Dunlap 1980, 

Ritchie and Stevens 1979, Stone et al,1979 

However, in this study, the seedlings had 

received over 550 chillhg hours at both 

nurseries. So chilling reguirments were not 

likely a problem, 
0 .+..---- ---- -.----- ------IT ----- ( 

3 

Planting Date 

2/12 3/4 3/26 4/17 5/9 5/30 

Figure 2. Mean number of new roots by nursery for 

the 1985 planting season. The first 

date indi'cates fresh lift levels. Open 

box plot=New Kent; "x" plot=Summerville. 

The 5 seedlot RGP mans of both nurseries 

virtually identical trends in storage 

(Figure 2). Early, rapid declines in RGP were 

followed by a sharp increase 12 weeks after 

lifting. Large increases have been observed in 

other studies, (Barden and Feret 1986, Feret et 

al. 1985~1, just before and after rapid declines 

took place. An explanation for this "burstw of 

IIC;P may be that it is a response of the seedling 

to a stressful environment. The high W? levels 

of the fourth planting date coincided with the 

highest survival of the study. 

Smmerville seedlings had consistently higher 

IIC;P than New Kent seedlings after storage (Figure 2). New Kent seedlings averaged less 

than 7 new roots on every planting date, except 

planting 4, while SL.lnanerville seedlings averaged 

more than 7 new roots for each storage duration, 

except planting 5. 

AtWA results indiated that all main effects 

(nursery, planting date, and family) were highly 

significant for RGP, and that all first order 

interactions were also highly significant (Table 

2) . The strong interactions were primarily due 

to family rank changes from nursery to nursery 

over the storage durations, and to the 

decreasing differences among nurseries over the 

longer storage durations. 

There was no obvious trend in survival across 

planting dates, possibly due to increasing rainfall over the planting season. Shmmerville 

seedlings had significantly higher survival on 

all planting dates. Considering seedlots, only 

the seed orchard mix (42-H) had significantly 

higher survival overall. Som nursery x family 

interaction was evident, due to 6-8 having the 

lowest survival from New Kent, and the second 

highest from Smmrville. 

First year height increment was calculated for 

the surviving trees uf each plot. There was a 

Table 2. ANOVA table for number of new roots 

during the 1985 planting season. 

F values are significant at 

p < 0.005 -- -- 

Source d f S S F 

planting date 

nursery 

f mily 

block 

nursery "family 

nursery*planting date 

family*planting date 

error 

steady decline in height incranent over the 

planting dates. There were large differences 

among families, and overall differences amng 

nurseries were the most consistent effect. New 

Kent seedlings averaged only 55 % of the height 

increment that Surmnerville seedlings averaged. 

The differences among blocks ranged from 13.25 

cm to 14.83 cm, arid were the smallest of the 

main effects. 

Field survival overall was significantly 

correlated with RGP (r = .56, p(.01) . Simple 

linear regression was used to relate survival to 

new root ndr. Various transformations of 

nurnber of new roots and survival were modeled. 

New root nwrber regressed on the logit [log 

(y/l y) I of survival percentage provided th& 

best fitting linear model (Figure 3a) . After sorting the data by planting date to 

eliminate the confounding effects of different 

soil and weather conditions, the fit of the 

various rnodels improved greatly. The log 

transformation of new root nurrber result@ in a 

good fit (Figure 3b-£1. Only the final planting 

date (Figure 3f) failed to have a significant 

relationship between RGP and survival. 

Height increment was significantly correlated 

with FGP over the first 4 planting dates. The 

overall correlation was moderately strong and 

highly significant (r = -65, p(.01). The trend 

of increasing height increment over increasing 

ntrmber of new roots was more nearly linear than 

the survival trend over EiB. Thus, various 

transformations only improved the del 

moderately. !Fhe final model used the square 

root of new root nurnber (Figure 4a). 

After sorting the data by planting date to 

eliminate the confounding effects of planting 

earlier or later in the season, the fit of the 

rnodels increased greatly (Figure 4b-4f . 
0 -P-,--*-------------------------------------- to Fig. 3a 

-.S 5, 0 10 20 40 i 

number of new roots 

I 

I 

I 0 Fig. 3c 

I 

634 I - I 1 

0 .s 1 1 .b 

log10 new root number 

Fig. 3e 

W+ I I 1 

R '7 *a 1.1 1.5 

log1 0 new root number 

0 

40, 

.6 .S 

I 

1 -2 

I I 

1 .5 

log10 new root number 

Fig. 3d 

. -.I 0 

I 

.5 

I 1 

1 1.5 

log10 new root number 

Fig. 3f 

D 60 t I i 

0 J .6 .S 

log10 new root number 

Figure 3. Matiomhip between field survival one year after planting and root growth 

potential mepureid as nrmber of new roots. 3a. Overall relationship for 5 

p1antiI-q~ (r =0231; p < 0.01) ; 3b-3f, su~ival-EP relationships £05 plantings A-5 

respectivsly (r 4.76, p < 0.01 for 3b; r 4.51, p < 0.01 for 3c; r =0.41, p < 0.03 

for Mi r 10.65, p < 0.01 for 3e; 3f no significant relationship. 
0 -- -T---. 

0 1 2 3 4 5 6 

squareroot of new root number 

24 I 

Fig. 4c 

s I",- --f-----------7-- T-v 

o a P o 1s 20 25 

number of new roots 

7 $,.---A 13-,-.--______-.-v~~_.--.___1 

0 5 10 15 20 

number of new roots 

Fig. 4b 

7 1 

0 I 

5 5 10 t 

15 20 25 30 35 

number of new roots 

I - 

I Fig. 4d 

7 /00,--__ -7 1 

0 S 10 15 

number of new roots 

La Fig. 4f 

4 -- -T--'---------- -7 

0 2 4 6 u 

number of new roofa 

Figure 4. Relationships between first-ye? height incrwent and XP. 4a. Overall 

relationship for 5 plantings (r =0.65, p < 0.09. 4b-4f, height incram$-EP 

relationships fo~ plantings 1-5 respective9 (r =0.80, p < 0.01 for 4b; r =0.68, p 

< 0.01 for 4c; r =0,60, p < 0.01 for 4d; r =0.61 p < 0.01 for 4e; 4f, no 

significant relationship. 
new root nwer pruvidd the best 

fit, but the last planthg date reult& in no onship betma keighk 

S~U* S~M& VEkw CJ 

nursery, family, and lift date, and new roots were very kig rrelatsd. 

mille nursery mnsbtat.ly producd 

seedlings with higher W, ddhough lX2 patterns were very similar at both nurseries, 

RB was shown to be a good prdietor of 

survival, and a better prr&i&car sf height 

growth, especially twder stxessfuf. conc'litions. 

The lack of correlation on the 1st plmthg 

date was probably due to the narrow range of 

values, (only 1-6 new roots (Figure 3f 1 1 , and 

the lack of stress after plmting due to wet. 

field conditions, T$GBJ wuld logically be less 

critical for suuvivd under well. mter& 

conditions, aich would &low klae planted, 

suberized roots to be adegaate for rnoisture and 

nutrient uptake. 

tic trmd in surrsival was clearly 

in aces8 of 12 new rmts yielded 

little wrovment in suwiv& re 3a). A 

value of 10 or mre nw roots s to be 

neccesary to ensure sunrival of at lest 80%. 

Height growth was mre strongly wrrelatd 

with RGP than sumival. The hhear trmd 

persisted up to BGP levels of 20 new rosts. BGP 

increases approaching this value rsult& in 

relatively mller ineredses in height herment 

(Figure 4a). 

The authors acknowldge with (sppreiation the 

financial and loqisticila, sumrt of 0, mrville, SC, and the Virgbia wt, of 

Forestry, M Kent, VA, 

Barden, C.J. card P,P, Ferret, 1986, Root gro*h 

potentid of loblolly pine sedlhgs held in 

cold sbrqe wder differing in cold storage 

under differbg mistrare trea 

1985 Wuthern Forest Wnrseq mnfer~~ce, Aug, 

1986, P'ensamla, FL (irb prss). 

Boyer, J,N, md D,B, ,South, 1984, For-t. 

nursevy praetics in the autk, S, J, &pf., 

For, 8~67-75, 

Brissette, J,C, ad T,C, Raberts, 1984, 

ling size and liftbg date effects on root 

growth potentid of I&lolly pine from two 

Arkansas nurseries, U,S,B,W, Tree Plmter's 

Notes, 35:34-38, 

Burdett, A,#, 1979, Ner~ nnetms for *muring 

root. growth capcity: their value in asssshg 

lodgvle pime stock qdity, Cm. J, For, Res, , 

9: 63-67. 

Carlson 1985, Effects of natural ehalhg and 

cold storage on bu&re& md root groeh potential of loblolly pine ( L*). can, 

J. For. Res. 15:651-656. 

DeWald, LoE., P.P. Feret, and R.E, Kreh, 1985a. 

A 15 day hydroponic systm for me~usring root 

growth potentrid, U: Prw, Third Biennia2. 

South. Silv, Res, Gonf, Ngv. 1984r Atlanta, GA, 

3:4-10. 

Wald, LeE,, P,P. Feret, ad R,E, Kreh, 198513. 

Genetic variation in loblol1y pine root growth 

potential. Proc, Suthern For. Tree Impr. Con£, 

Gulwrt, MS. pp, 155-162. 

DeCjald, L.E. 1986, Changes in Pblolly pine 

root growth potatid over time, during cold 

storage, arad mng half-s* fmilies. Ph,D, 

Dissertation, V,P.I. & S.U, 146 pp, 

Feret, P,P. and R.E. Kreh. 1985, &&ling root 

growth potmtial as an indicator of Ioblolly 

pine field perf0 e, For, ki, 3121005- 

1011. 

Feret, Pep., R.E. Kreh, and L.E, Mald. 1984, 

Root growth potenti&- one tool for masuring 

loblolly pine s&lJlng quality. &: Proc, S. 

Nursery Gcbnf. pp. 129-137, 

Feret, P.P., R,C, Freyman, and R.E. Kreh. 1985a. 

Variation in root growkh potmtial of loblolly 

pine from seven nurseries, a: Proe, Joint 

IUFRO Auburn Univ. Intern. on Mrrsery 

Management Pmctices for the Southern Pines. 

Aug. 1985, Wntgomry, =a. ~~317-328, 

Feret, P.P., R.E. Rreh, and G, MralPigan, 1985b. 

Kfe~ts of air-drying on survival, height, and 

root growth potentid of loblolly pine 

seedlings, S, J, Apple For. 9:125-128 

Feret, P.P., R,E, Kreh, and L.E. MTald, f985c. 

fioot growth potmtid of stored loblolly pine 

seedlings, a: Proc, mird Bimid auth. Silv, 

Res, Conf, Wv, 1984, Atlanta GA, 3~18-24, 

Jenkhson, J.L. 1978, Sfect of nursery coditioning and storage on root gro&iif ca~ity and 

early sumivd of seletd gqrqhic sources of 

)Douglas-fir, true firs, md pnderssa pine, 

Idt Mrsery Min, Rudy 1976-1977 Rep. 

P,S,W. Forest and mge Ekp, Rn, BrkeLq, Gzl, 

30 pp. (unpublished) , 

J&hson, J,L, 1984, Srx3 source liftkg 

winhws *rove plantation est&lishment of 

Pacific Slope Bugls-fir. &: Duwea, N,L. and 
Johnson, J.D,, D.L, Brdett, R.M. Burns, T,A, 

Dierauf, S,E, Ffanald, and J.M, Stone, 1982, 

Pine sedlhg production in the South: A 

prObla analysis, PubI. No, RJS-6-82, Sch. Far, 

and Wild. Sci, V,P,Z, and S,U, Blackburg, VA, 

Kozlowski, T,T, artd W.8, eblts, 2.984, 

Growth of roots and root hairs of pine and 

har sdlings in the Pi 

46:750-754, 

Kramer, P,J. and R.W. Rose. 1985. 

Physiol~icd characteristics of Loblolly pine 

seedlings in relation to field prfo 

Proc. Joint IUFm Auburn Cniv, I.U,F 

on Nursery Mmqment Practices for the Southen: 

Pines, pp. 416-440, Aug, 2985, imntgoniery, 

Ma. 594 pp. 

Nambiar, E.K.S. 1980. Root configuration and 

root regeneration in seed2 hgs, 

New Zealand J. For, Sci, 10:249-263, 

Rhea, SOB, 1977. The effects of lifting time 

and cold storage on root regenerating ptmtial 

and survival of sycmre, sweetgm, yellow 

poplar, and Loblolly pine seedlings, M.S. 

Thesis. Clemson Univ, 108 pp. 

Ritchie, G.A. 1984, %sessing sedlbg 

quality. &: M,L, Duryea and T-14, Landis 

(eds.) Forest Nursery Manual: Production of 

Bareroot Seedlings, pp, 243-259, M. Nijhoff 

Publ. The Netherlands. 385 pp. 

Ritchie, G.A. and J.R. Ddap. 1980, Root 

growth potential: Its devel 

expression in forest tree sedlings, N,Z,J. 

For. Sci, 10:218-248. 

Ritchie, G,A, and R,G. Stevens, 1979, The 

effects of lifting date, storage rqbe, and 

moisture deficits on root rqr?nera"c.on and 

survival of 2 + 0 mug1~-fir plmthg stock, 

Weyerhaeuser For, Res, Tech. Rpt, 

042-2203/79/37, 19 pp. 

Stone, E,C, 1955, Poor sunrival and the 

physiological condi"con of pliulthg stock, For. 

Sci. 1:90-94. 

Stone, E.C, and E,A, Norberg, 1979, Use of 

root growth capacity in develophg propgation 

regimes, storage criteria, and nurselby stock 

certification. 

stands. The True Fir Maraagment Gaoprative, 

Rding, a. 35 pp. 

Sutton, R.F. 1980. Planting stock quality, 

root growth capacity, field prfo 

three boreal conifers, Hers Zealand J. For. Sci. 

10: 54-71. 

Venator, C.R. 1981. Iqroved survival and 

growth justify planting only top quality 

seedlings. Forest Famr. Oct. 1981, pp. 6-7, 

18, 

Weaver, C,H,, B, Izlar, K. Xydias, and F,S. 

Broerman. 1980. Trends in Southern forestry 

industry pine plantation survival 1960-1978. 

a: Proc. of A.S.A.E. , on qineerhg 

*stems for Forest Regeneration. March 1981. 

A.S.A.E. Pub1. 10-81:53-55. 
Wt Gro&h Potatial has been sh to be a gd prdictor sf sumival 

pr&ability after outplanting. It has been siqgested that the relationship 

between EP iuu3 field performance might be strengthened when sedlings are 

planted on a stressful site. An eyperi was condue& where seedlhgs of 

planted at tw levels o ter stress, -tern white pine 

L.) seedlings were hand lift& from nurseq b&s on eight 

occasions from October 15, 1985 Lo mrch 19, 1986. Seedlhgs from "che first seven lifts were stored at 2 C and following the last lift date ese&lin;gs from 

611 eight lift dates-were included in a 21 day hydroponic IZGP test, Due to the 

relationship of lift dake and storage duration on RGP, this rsultd in sets of 

seedlings with varying RB. Subsets of seedlings from each lif"cng ate wre 

included in a field outplanting test. A split-j$ot design was used for the 

study with irrigated vs non-irrigated treatments as mbplots and lift date a 

subplots, does show promise as a masure of eastern white phe sedli~ 

quality. The cxmsistent ability of a seedling lot to produce new roots qpars 

to be more important than the average rimer of new roots or roqblogical 

attributes in predicting field performance. PI(;;P was sig~lificantly correlatd 

with height increase and the relationship was strqthensd on non-irrigatd 

plots. 

quality forest tree seedlings providing 

low mortality and rapid growth are always a desired component of any reforestation program, 

Nurse- have long sought a seedling grading 

system that will accurately and consistently 

predict outplanting success. Although it has 

been decades since Wakeley (1949 first 

discussed the importance of seedling 

Mysiological status, mrphological grading 

still remains the industry% principal method of 

rating seedling quality, 

In 1955, Stone introduce3 the concept of mot 

Growth Potential (RGP) as a sixnple method of 

measuring the ability of a bare-root seedling to 

produce new roots a£ter planting. Theoretically, a seedling with high EP could rapidly 

re-establish contact with the soil and thus 

capitalize on available soil misture and 

nutrients, More recently, Ritchie (1985) has 

suggested that RB may be considered a general measure of seedling vigor because it is actually an indirect test of the status of several 

critical Mysiological spterns. 

"Paper present& at Southern Silviculture 

Research Conference, Atlanta, Georgia, 

4-6, 1986. 

"~raduate Research Assistant, kssociate 

Professor, and Assistant Professor, respectively, VPI&SU, Black&urg, VA 24060. 

Sbee being htroducd by Stone, RZ has been 

the fwus of nmrous studies ad, in general, 

EP is a good predictor of sedlisrg field 

including: loblslly pine ( 

ponderosa pine 

and Kreh 1985, Feret et ale 1985, J&hson 

1978, Ritchie md Wen. 1985, H'tchie and Dunlap 

1980) . 

There have been sewraS. notale exceptioras 

where has not predicted or has been a poor 

predictor of first year surviml andlor first 

year growth (R;nea 1977, Sutton 1980, Brissette 

and RQberts 1984, maid et ale 1985) . In the 

latter two cases, the autkrs noted that first 

year survival was excellent and that field 

Gonditions were not very strasful, This implies 

that differences in root gro~h and general 

physiolqicdt corrdition my be of varying 

irrg?ortance urder differat field conditions. 
2-0 eastern white ehe sed%ings \vet-e had 

lifted on eight wcaions from OiltoDer 18, 1985 

to March 19, 9986, SeeALirgs were lift& from 

the Virgislia Division of Forstsry" Augusta 

ro, VA,). Gn each lift date, 

s&2bgs were rzmdoiiey seie&& from eacri sf 

three preest&lish& blocks. Sedlirags frorn 

the first 7 lift dates *re do&le wrq@ in 

plyetkiyiene bags md placd into cold storage 

at 2 C, 

Follottshg the last lift date, 15 seedlings per 

blockllift date mrbhation were included in a 21 day hydropnic RGP test as descrfied by 

Dewdld et a1, (19841, B-kockhg for the EP test was maintahd as fmm the nursely. Followhg 

the test nw white roots greater than or equal 

to 0.5 cw,timter in lmgkh were cowed. Dry 

weight of roots and sbots mre determined after 

drying to a costant weight at 60 C. 

Three days after the initiation of the EP 

test (March 23 and 24, 9974) subswles from 

each block/lift date m&inatiion were outplantd 

at the Reynolds Homestead Research Center 

(Critz, Virghia). Tlze outplanting consisted of 

three replicate blocks (mahasabed as from the 

nursery and the EP test) plat& on a plowed 

and disked old field site. A split-plot design was used with irrigatd vs non-irrigated 

treatments as the mbplot and Lift dates as 

subplots. Each mainplot then rmdomly 

planted, using 0,5 meter spacing, with eight 

seedlings frorn each of the appropriake 

block/lift date corrbinations, Seedlings were root pruned to 12 cm below root coPlar, the same procedure used for the RGP test. 

Drip irrigation was provided around the stan 

of each seedling in a irrigation treated mainplot. Water was providd as needed so that 

irrigated trees received no less than 2.54 

centimeters of natural. andlor su~lemented 

precipitation per week. Cm July 17, all plots were hand weeded. Cki two dates, June 24 and July 

17, mid-day needle mter potential was measured on tw randomly selectd sedlings from each 

outplanting mhplot for both the January 3 and 

the March 19 lift data. Seedling water potential was mwured on a single needle fascicle 

using a pressure bo&, 

Seedling height groGakh md dimter groFzth was determined by mewuriqg se&l;ings at time of 

outplanting and agah on Sept&er 5, Survival 

data was collected on i.q 30, June 24, July 17, 

and Sept&er 5, 

To assess the effst of the irrigation treatment, seedling water ptmtial, survival, height 

growth, and dieter gro&h were analyzed using 

Analyses of Variance with a split-plot design. 

General lineax rqresion was used to determine 

the relationships betwen nrorphslogicd traits 

and EP mesurmmts to sumival, height growth, 

and dimten: grokkh, WqbLqical traits used 

were .-oat collar diixxeter -bet weight, rcot 

weigh A, and rw.ir-8sh~ot r,r_, ;GI? ~e~ur~1znts 

us& ere nimber of roots ad prcmt poor 

seedlhgs (a poor sedling was defkrx3 as one 

produchg less than 2 new roots). Walyses were mte using i;;r,lk iiiems, Data from irrigated and nmirrrigatd trea 

analyzd sepratdy, 

Analyses of varimce sbwd no significmt 

effect due tc~ irrigation on end of season survival, height hcrcsrient, relative height 

diameter incrgnent, and relative dirnneter 

Survival as mesurd on Nay 30 and seedling 

water potential as mmurd on both June 24 and 

July 17 did s gnif ?;cant differences in 

irrigation tr t at the alpha = 0,05 level, 

lvleans for both irrigation treatmats are shown 

in Table 1, 

Table 1, Means of first year field perfo 

for irrigated (IN and non-irrigatd (NON) 

eastern white pine sedlings. 

% Survival (May 30) 11 9 7 7 ~t * 

% Survival (Sept, 51 74 7 6 ns 

Hgt Incrtsnent Ccm) 10,%0 8-00 ns 

Relative Hgt. Inc, 

(Hgt Inc,/initial hgt, 

(%I 4 8 4 0 ns 

Diameter Incrmmt (rmn) 1,76 1.69 ns 

Relative Dim., Inc, 

(Dim, incdinit. dim,) 

(%I 4 4 44 ns 

Needle Water Btmtia;? CWa) 

June 24 -P,13 -1.58 * * 

July 17 -%,lE3 -1.57 * * 

Precipitation data for the time period studied 

and survival for two irrigation trea 

shown in Figure 1 and 2, reswctively, 
consistent predictor of first year field 

Seedling El?.- Seedling FZP wa mre consistently correlated with first year field 

e than mrpblogical traits QTbte 2). 

Altbugh FGP was inconsistent in predicting 

seedling survival and showed no signifslemt 

correlations with dimreter jflcr 

consistent predictor of rdative height 

t, F?GP showed better correlations with 

height incrment on non-irrigated plots, IGP as 

measured as percent poor trees (percentage of 

seedlings in RCP test growing less than 2 nr?M 

roots) was more often correlated with field 

performance than RGP as masurd by avenage 

rimer of new roots, 

F tests show no significant differences in 

slope or intercept between irrigated iuzd 

non-irrigated data in a regression of % poor 

trees on relative height incr 

when separate equations are fit to both sets of - data, the regression using the non-irrigated 

data provides a much better fit than that using 

the irrigated data (Figure 2). 

May June July 

Month 

March 

r = -0.60 I r, = 24 I 

604 S.E. = 10.00 

an 0 

4%- IW 

-+ Non 

10 4----- -7-- ---- - - -1 -- - ---- f-- - ---1 

0 20 40 60 80 

X poor seedlings 

Figure 2.--Relationship bemen percent poor 

seedlings and relative height incr 

non-irrigated autplanted 2-0 eastern white pine 

seedlings 

70 4 -. -- .. --. - -. - -. - -- - -7 

3ji 4/l 5/1 6/1 7/1 8/1 911 

Date 

Figure 1, (A) ,Spring and smr precipitation 

at Reynolds Homestead Research Center, Critz, 

!LA. and (B) first year survival for irrigated 

(Irrf and non-irrigated (Nan) outplanted eastern 

white pine seedl.ings. 

Although there were no significant irrigation 

differences as reflected in end of season 

survival or gro&h, there were definite 

differences in seedling stress levels between 

the tw treatments as is seen by the signifimt 

differences in seedling water ptwtial. 

Irrigation sew to have postponed mrtality 

(Figure 1) but did not prevent it. apprmtly, 

certain seedlings were of such low qr~aity that 

Morphol%ic& traits.- With a few exceptions, 

mrpholqical traits were generally not 

significantly correlated to field perfo 

(Table 2) . Wt/shoot ratio was signifi 

and positively correlated (P I ,051 .05) to 

t on non-irrigated plots. mot 

collar diameter was significantly and positively 

correlated in one instance but was not a 
Table 2.--Correlations (n = 24) between first year field performance and 

Wt Growth Potential (RGP) and morphological traits of irrigated (1rr.f 

and non-irrigated (Non.1 eastern white pine seedlings. 

----------------------------------------------- 

Seedling fimZ Wrpholqical traits 

----------- ------------------- 

mt 

New %poor collar Shoot Root Root to 

Field roots seedlings diameter wgt. ~igt. shoot 

Performance (nderf (%I (nrm) (g) (g) ratio 

Irr. .05 ns -.25 ns -00 ns .33 ns .31 ns .Of ns May 30 

Non. -04 ns -.I5 ns .03 ns .06 ns .lo ns .10 ns 

** 

Irr. .09ns -.44 .00ns .33ns .31ns ,2911s 

Sept. 5 

None .10 ns -.22 ns -.07 ns -04 ns .03 ns -16 ns 

Irr. -24 ns -.37* .03 ns -15 ns -01 ns -29 ns Relative (%) ** *** * ~r 

Non. .40 -.60 .06ns .01ns .26ns .47 

Irr. -25 ns -.08 ns .13 ns .18 ns .21 ns .13 ns Total (an) 

Non. .09ns -.21ns .40** .12ns .05ns .21ns 

Irr. .21 ns -,16 ns -- I .02ns .05ns .11ns 

Relative (%I 

Non. .04ns -.Ions - .17 ns .23 ns .16 ns ------------------------------p------------

* * * *** nsP>or=0.10; P<or=0.10; P<or=0.05; P < or = 0.01 

regression not run due to dependency of variables 

they could not survive even with sufficient 

moisture. 

It is not surprising that first year height 

growth did not differ significantly between 

irrigation treatments as eastern white pine 

exhibits fixed growth which is highly influenced 

by production of needle primordia the previous 

smr in the nursery. Since relative height 

increnent was increased 17% on irrigated plots, 

it does appear that cell elongation and/or 

division of the rib meristen was enhanced by 

irrigation. The lack of any difference in 

relative diameter increnent may have been 

because most diameter growth occurs in the 

second half of the summer and by then rainfall 

was providing more adequate soil moisture. 

RGP was a better predictor of height increment on non-irrigated plots than on irrigated plots. 

It appears that performance attributes such as 

RGP and some material attributes such as 

root/shoot ratio become more influential on first year field performance as field conditions 

become more severe. 

Percent poor trees accounted for 36% of the 

variation in relative height growth of 

non-irrigated trees which was considerably 

better than any morphological trait, Since 

eastern white pine is a determinant species, SP 

may provide as good or better correlations with 

second year growth. General vigor during the 

first smr could potentially impact needle 
prhrdia production which will largely 

determine the next years growth. 

Although RGP did not show a good linear 

relationship with survival, it does seem to have 

sane value as a predictor of seedling survival. 

a plot of percent survival vs 

percent poor seedlings for both irrigated and 

non-irrigated trees. There appears to be a 

threshold level at abut35 percent poor 

seedlings below which there is consistently high 

outplanting survival. Seedling lots with less 

than 35 percent poor seedlings (42 percent of 

those tested) in the W test resulted in an 

average of 88 percent survival with a 

coefficient of variation (C.V.) of 15 percent. 

Seedling lots with over 35 percent poor 

seedlings in the R13? test were highly variable 

in survival response and resulted in an average 

of 66 percent survival with a C.V. of 38 

percent. Irrigated irrigated seedlings 

show approximately response , 

36- Non 

% poor seedlings 

Figure 3.-Relationship betwen percent poor 

seedlings and first year survival for irrhated 

(Irr) and non-irrigated (Mn) outplanted 2-0 

eastern white pine. 

Percent poor trees was a bettex predictor of 

both survival and height growth than average 

r of new roots. This indicates that, with 

eastern white pine, RZ may be more irsportant as 

a general measure of s-ing vigor than as; a 

measure of a seedling8 biliky to renew intimate 

contact with the soil. Krafner (1985) indicated 

that in some speciw sukeriz@d roots may be more 

efficient at water and ion uptake than is 

generally tko~ght, !l%erefore, the difference in 

subsequent field performance, from a RGP of 0 to 

2 new roots may be greater than fra 2 to 10 new 

roots. The difference is really the ability of 

the seedling to be or not to be physiologicdlfy 

active. This point may seem very obvious but as 

this measure of seedling quality is visually 

indistinguishable between seedling lots, the 

Wt Growth Fotential test is a valuable method 

of measuring general seedling physiological 

and it ion. 

It wars from this study that RGP does show 

promise as a measure of the quality of eastern 

white pine seedlings. The consistent ability of 

a of a seedling lot to produce roots appears to 

be more important than t&e average number of new 

roots or than it's morphological attributes in 

predicting field performance. A threshold seems 

exist where the best seedlings, by measuring 

percent poor seedlings, provide consistently 

excellent survival. RGP is significantly 

correlated with height increase and the 

relationship is strengthened on non-irrigated 

plots. 

ACKN(XJLWEMENT:-- F?e appreciate the cooperation 

of Wayne Mcbee and Tom Dierauf of the Virginia 

Division of Forestry without which this study 

could not have been accomplished. 

LITERArn CITED 

Brissette, J. C. and T. C. Roberts. 1984. 

Seedlhg size and lifting date effects on root 

growth potential of loblolly pine from two 

Arkansas nurseries. Tree Planters Wtes 

35: 34-38. 

Dewald, L. E., P. P. Feret, and R. E. Kreh. 

1984. A 15-day hydroponic system for measuring 

root growth potential of stored loblolly pine 

seed1ings.U Proc. Thixd Biennial Southern 

Silviculture Research Con£., pp. 4-10. Atlanta, 

Ga., Novetber 1984. 

, 1985, Genetic variation in loblolly 

pine rwt growth potent#.d. Southern Forest Tree 

mrovmt Conference. May, 1985. &: Proc, 

18th Southern Forest Tree Improvement Conf. May, 

1985, Long Beach, MS. pp. 155-162, Sponsored 

W1. No. 40 of the Southern Forest Tree 

Improvement Cornnittee. 

Feret, P. P., Re C. Fr.eyman, and R. E. Kgeh. 

1985. Variation in root growth potential o-f 

lcblolly pine from seven nurseries. u: Proc. 

I.U.F.R.O. - Auburn Univ. w. on Nursevy 

t Practices for the Southern Pines. 

Aug. 8-7, 1985. Birminghm, Al. pp. 317-328, 
Feret, P, P. and R. E. Kreh, 1985. Seedling root 

growth potential as an indicator of loblolly 

pine field perfo e. For Eki* 31:1005-1011. 

Jenkinson, 1978. Effect of nursery conditioning 

and storage on root growth capacity and early 

survival of selected geographic sources of 

Douglas-fir, true firs, and pnderosa pine. 

ldt Nfursery , Study 1976-1977 Rep. PSW 

Forest and Range Ekp. Stn., USX, USFS, 

Berkeley, CA, 30 p. 

Rhea, S.B, 1977. The effects of lifting time and 

cold storage on root regenerating ptential and 

survival of sy-re, meetgm, yellow poplar, 

and loblolly pine seedlings. M.S. mesis. 

Clanson Univ. 108 p. 

Ritchie, G. A. 1985. Root growth potential: 

Principals, procedures, and predictive ability. 

U Proc. Cvdluating Seedling Quality: 

Principals, Procedures, and Predictive Abilities 

of Major Tests. Workshop held September 16-18, 

1984. For. Res. Lab., Or, St. Univ., 

Corvallis. 

Ritchie, G, A, and J. R. Wlap, 1980, Root 

gro~h potential: Its devel t and wrssion 

in forest tree seedlings. New Zea. J. For, Sci. 

10:218-248. 

Ritehie, G, A,, J, R, Roden, and N. Kleyn, 1985, 

Physiological quality of lodgepale pine and 

interior spruce seedlings: effects of lift date 

and duration of freezer storage, Can. J, For. 

Res. 15:636-645. 

Stone, E, C. 1955. Puor survival and the 

physiological condition of planting stock. For. 

Sci. 16:230-239. 

Sutton, R. F, 1980. Planting stock quality, root 

growth capacity, and field perfo 

boreal conifers, Hew Zea, J, For. Sci, 10:54-71, 

Wakeley, P. C. 1949. Physiological grades of 

southern pine nursery stock. Proc. 49th. Ann, 

Meet, Soc. Am. For, PP, 311-312. 
Soil-Site-Stand Relationships 

Moderator: 

Carol G. Wells 

Southeastern Forest Experiment Station 

INTEGRATED SITE CLASSIFICATION IN THE SOUTHERN APPALACHIAXS: 

1 / GEOLOGIC VARIABLES RELATED TO YELLOW-POPLAR PRODUCTIVITY2 / W. Henry NcNabAbstract.--Stand characteristics of yellow-poplar were significantly 

different for sample plots located on colluvial soils derived from metamorphosed igenous rocks compared with soils derived mostly from metamorphosed coarse clastic sedimentary rocks in the Bald Mountains of North 

Carolina. Mean site index and d.b.h. did not differ between rock ciasses. 

Analysis of covariance, with mean stand age as covariate, indicated that 

stands over igneous rocks had an average of 30 more yellow-poplar trees 

per acre and 37 ft2 more basal area than stands on sedimentary rocks. 

There was no difference in the density and basal area of other species. 

Available geologic mapping, even at a scale of 1:250,000, appears to 

provide useful information as a component in a hierarchical site classification system for other areas in the Southern Appalachians. 

INTRODUCTION 

The geology of the Southern Appalachian Mountains is a complex arrangement of rock types that 

can vary widely in physical and chemical properties over relatively small areas. Geologic components could account for some of the variation in 

application of soil-site relationships beyond the 

original study area and help explain the sometimes 

marked differences in species composition and productivity of hardwood stands in adjacent watersheds. It is well known that the chemical and 

physical characteristics of soils largely result 

from lithologic properties of the parent material. 

Although modern soil mapping is well under way in 

many mountainous counties, the pace is slow and 

few reports have been published that could be useful in site classification and evaluation. Also, 

the value of soil series in the accurate evaluation of site productivity is sometimes questioned, 

If stand productivity is related to parent rocks, 

however, then geology could provide immediate useful information at an upper level of a multicomponent site classification to gain accuracy in prediction of site and stand characteristics. 

Information is relatively abundant relating 

overstory and understory species associations with 

soils derived from various parent materials. However, little has been reported on correlations of 

the tree overstory productivity with geologic 

factors, especially in the Southern Appalachians. 

Graves and &nk (1985) reported that tree species 

and basal area were not significantly different 

between two adjacent sample locations in northeast 

Georgia: one over marble and Limestone parent 

rocks, and the other over schist. Rohrer (1983) 

studied vegetation over three rock groups in 

northwestern North Carolina and reported that each 

group weathered into soils with different texture, 

mineralogical composition, and moisture availability regimes. He found that density and basal 

area of tree species, expressed in relative terms 

as importance values, were closely correlated with 

rock group. 

Geologically, all rocks are placed into three 

classes: igneous, sedimentary, and metamorphic, 

depending on their origin (Whiteside 1953) . Rock 

class is commonly used in soil classification and 

is usually readily obtainable from small-scale 

generalized geology maps. Warren and Matheson 

(1949) found rock class helpful in classifying 

sites in British Columbia for productivity of 

Sitka spruce (Picea sitchensis (Bong.) Carr.). 

The most productive sites were associated with 

sedimentary rock formations in comparison with 

nearby lower quality sites on igneous rocks. Tnformation on the relative value of geologic variables is needed for a proposed multicornponent site 

classification being developed for the Southern 

3 1 Appalachians .- 

A study was designed to test the null hypothesis that parent rock has no effect on characteristics of yellow-poplar (Liriodendron tulipferz 

L.) stands. The study has the specific objectives 

of evaluating the effects of parent rock on site 

quality, growth and yield, and herbaceous vegetation. Results have been summarized on the value 

of geological variables in modeling site index as 

1' Paper presented at the Fourth Biennial 

Southern Silvicultural Research Conference, McNab , i4'. Henry. Rationale for a multiAtlanta, Georgia, November 4-6, 1986, factor forest site classification system for the 

Southern Appalachians. In preparation. 2' Silviculturist , Southeastern Forest 

Experiment Station, U.S. Department of Agriculture, Forest Service, AshevilPe, KC 28804. 
a function of topographi.b' The purpose of this 

symposium paper is to present results of the 

effects of geologic rock units on stand 

characteristics. 

The study site was located along a 30-mile 

seemLent of the Bald Mountains of western North 

Carolina in Madison and Haywood Counties, along 

the boundary with Tennessee. The town of Hot 

Springs roughly bisects the study area. Elevations in this area range from 1,500 to 2,000 feet 

in intermountain basins to more than 4,000 feet at 

several mountain summits. Soils on high-quality 

sites are mesic Typic Hapludults and Umbric 

Dystrochrepts that have formed in colluvium on 

lower slopes and in coves. Slope gradients range 

from 10 to >60 percent. Precipitation at Rot 

Springs averages 45 inches annually, but increases 

at higher elevations. The Bald Mountains were 

selected for this study because of their nearness 

to Asheville and the availability of National 

Forest lands for plot installation, but primarily 

because the contact zone of several major lithostratigraphic units occurs within these mountains. 

Most of the rocks in.this area are predominantly quartzo-feldspathic, and thus are relatively 

low in mafic minerals such as hornblende, biotite, 

and Ca-rich plasioclase feldspar. The igneous 

rocks are mostly late to middle Proterozoic 

granitic to granodioritic gneisses . The sedimentary rocks are coarse to fine-grained clastics 

in the late Proterozoic Ocoee Supergroup, which 

includes the Walden Creek Group, undivided, the 

Snowbird Group, undivided, and the Longam Quartzite 

of the Snowbird Group. Both rock classes have 

undergone low- to middle-grade regional metamorphism. Except for intensive study of the Hot 

Springs "geological window" in Madison County, 

no detailed geological mapping is available. 

A total of 60, circular 1/4-acre plots were 

located in even-aged yellow-poplar stands. Only 

stands with 75 percent or more of yellow-poplar 

in the overstory were sampled. Plots were grouped 

in clusters of 5 to 10 plots each to provide replication within a specific type of rock. Increment 

cores were taken from three to four dominant and 

codominant yellow-poplar trees in each plot to 

estimate mean stand age. Each tree sampled for 

age was also measured for total height. Site index was determined by height-age curves developed 

by Beck (1962). All trees >4.5 inches d.b.h. in 

the plots were recorded by species, diameter class, 

and canopy crown class. The lower crown class 

included suppressed and intermediate trees; codominants and dominants were placed in the upper 

class. Besides yellow-poplar, other common 

deciduous overstory species included sweet birch 

(Betula -- ienta L.), northern red oak (Quercus rubra 

L.), and black locust (Robinia pseudoacacia 2.). 

Red maple (Acer rubrum L.), flowering dogwood 

(Cornus f lorida L.) , and sourwood (Oxydendrum 

arboreum (L.) DC.) formed a large proportion of 

understory species. Two coniferous species, 

eastern hemlock (Tsuga can-adensis (L.) Carr .) and 

eastern white pine (Pinus strobus L.) , were 

occasionally found in the understory. Rhododen- 

-- dron maximum L. was the principal shrub species, 

particularly where sample plots were adjacent to 

streans. For the most part, the yellow-poplar 

overstory was even-aged, but some stands included 

an occasional large tree, presumably a residual 

from past harvesting activities. Field data were 

summarized by two groups--yellow-noplar and miscellaneous species. 

Following plot establishment, rock type was 

determined by sampling half of the plots in each 

cluster. Rock types were combined in six groups 

according to origin, texture, mineralogical cornposit ion, and other data ..?/ Geological characteristics of the rock groups have been summarized-- 

each rock class consists of two or more rock 

groups; each group contained from three to six 

rock types; in addition, site index was summarized 

by rock class.b/ This work indicated that although site index did not differ by rock class, it 

was correlated with a different set of topographic 

variables associated with each rock class. 

Rock class is used in this report because it 

can readily be determined from small-scale 

geological mans. Stand conditions by rock class 

are presented in table 1. The majority of sample 

stands were from 50 to 60 years of age and ranged 

from 110 to 130 in site index. Generally, sample 

stands on both rock classes were on similar landforms and had similar topographic characteristics 

except that few plots on sedimentary rocks were on 

south-facing aspects. 

The effect of rock classes on tree density 

and basal area was determined by analysis of covariance, using mean stand age as the covariate. 

Chi-square analysis was used to compare tree 

counts in d.b.h. classes. All tests of significance were made at the 0.05 level.of probability. 

i/ Brief summary of twenty-nine yellow-poplar 

sites in Madison and Haywood Counties, North 

Carolina. Carl E. Werschat, Geologist, North 

Carolina Geological Survey Section. N.C. Dep. 

Nat. Resourc. and Community Dev., Asheville Reg. 

Off. 1/7/86. 

6' See footnote 4. 

41 McNab, W. Henry; Merschat, Carl E. 

Geologic and topographic factors affecting productivity of yellow-poplar stands in western North 

Carolina. In preparation. 
Table 1.--Distribution of sampled yellow-poplar 

stands, by site index class, rock class, and stand 

as!; 

other than yellow-poplar on igneous rocks, and 

about 16 percent on sedimentary rocks. 

Site Rock Stand age class (years) 

index class 30 40 50 SO 70 80 Total 

Table 2.--Density of average stand of yellow-poalar 

and aiscellaneous species, by crown canopy class 

and rock class 

-- Number of stands -- 

100 Igneous -- -- 1 -- -- -- 1 

Sedimntary -- -- -- -- 1 -- 1 

Rock Crown canopv class Both 

class Lower C~ner classes 

------- Kumber ~er acre -------- 

110 Igneous -- -- 2 1 -- -- 3 

Sedimentary 3 1 4 2 3 -- 13 

120 Igneous -- 4 5 -- -- -- 9 

Sedimentary -- 3461115 

130 Igneous -- -- 4 4 -- -- 8 

Sedimentary -- -- 2411 8 

140 Igneous -- -- 1 -- -- -- 1 

Sedimentary -- -- 1 -- -- -- 1 

All Igneous -- 4 13 5 -- -- 2 2 

YELLOW-POPLAR 

Igneous 53.0 62 .O* 115.09~ 

Sedimentary 39.4 41.4 80.8 

MISCELLANEOUS SPECIES 

Igneous 66.9 7.7 74.6 

Sedimentary 71.6 8.2 79.8 

TOTAL STAND 

Igneous 119.9 69.7* 189.69~ 

Sedimentary 111.0 49.6 160.6 

Sedimentary 3 4 11 12 6 2 38 

Total both 3 82417 6 2 60 

*Significant at 0.05 level of probability. 

Basal Area 

RESULTS AND DISCUSSION 

Density of Tree Stand 

Density of the average tree stand on the two 

rock classes is shown by species and overstory 

crown class in table 2. Correction for variable 

stand age by covariance analysis had little effect 

on the mean values. For the total stand, significantly more total trees and trees in the upper 

crown canopy class were present on igneous rocks 

compared with sedimentary rocks. About 20 more 

trees per acre in both crown classes were present 

in plots over igneous rocks. 

Most of the total stand differences resulted 

from the yellow-poplar component. Yellow-poplar 

stands over igneous rocks have an average of 15 

more trees per acre in the lower canopy class and 

22 more in the upper crown class than the stands 

over sedimentary rocks. The number of yellowpoplars per acre on sedimentary rocks was about 

equally distributed between lower and upper crown 

classes. However, on igneous rocks, an average of 

almost 10 more trees per acre were in the upper 

crown canopy. 

For the miscellaneous species, the ratio of 

trees in the lower and upper crown classes was 

about the same for both rock classes. About I1 

percent of the overstory consisted of species 

Average basal area of the stands (table 3) 

follows almost the same pattern of statistical 

significance as the tree stand. In soils derived 

from igneous rocks, the total stand has almost 

50 percent more basal area in the upper crown 

class and in both crown classes than stands over 

sedimentary rocks. As with stand density, most 

of this difference is attributable to the yellowpoplar stand component. Basal area of yellowpoplar in the upper canopy was over twice that of 

the lower crown component. This ratio was reversed for miscellaneous species, where the understory contained twice the basal area of the overstory. From 12 to 13 percent of overstory basal 

area consisted of miscellaneous species for stands 

on both classes of rocks. 

Diameter at Breast Height 

Quadratic mean tree d.b.h. is shown is table 

4. Although no statistical tests were made, it 

seems apparent there are no real differences in 

mean 13,b.h. of stands on igneous and sedimentary 

rocks, when averaged over all densities and ages. 

Yellow-poplars in the overstorp averaged almost 

16 inches and were more than 5 inches greater in 

d.b.h. than those in the understory. In com~arison, miscellaneous species in the overstory averaged 8 inches greater than the understory component. Much of this diameter advantage resulted 

from scattered residuals in the 21- to 29-inch 

6.b.h. classes. Averaged over both crowxi classes 
in the stand, the miscellaneous species component 

was about 3 inches smaller in d.o.h. than the 

yellow-poplar component. 

Table 3.--Mean basal area of yellow-poplar and 

miscellaneous species, by crown canopy class and 

rock class 

Rock Crown canopy class Both 

class Lower Upper classes 

---------- 2 ft /acre 

Igneous 

Sedimentary 

YELLOW-POPLAR 

MISCELLANEOUS SPECIES 

Igneous 28 .O 12.9 40.9 

Sedimentary 28.1 12.8 40.9 

TOTAL STAND 

Igneous 57 .O 98.4* 155.4" 

Sedimentary 49.9 68.3 118.2 

"Significant at 0.05 level of probability. 

Table 4.--Average d.b.h. of yellow-poplar and 

miscellaneous species, by crown canopy class and 

rock class 

Rock Crown cano~v class Both 

class Lower Upper classes 

Inches ------------ 

YELLOW-POPLAR 

Igneous 10.0 15.9 13.5 

Sedimentary 10.1 15.7 13.2 

MISCELLANEOUS SPECIES 

Igneous 8.8 17.5 10 .O 

Sedimentary 8.5 16.9 9.7 

TOTAL STAND 

Igneous 9.3 16.1 12.2 

Sedimentary 9.1 15.9 11.6 

Stand Diameter Distribution 

The average distribution of trees by d,b.h. 

class is shown in table 5. Because relatively few 

trees were over 20 inches ir 5iameter, trees 

larger than 20.5 inches d.F.h, were grouped into 

a single class. Only 2 percent of all trees measured were in the 21+ inches d.b.h. class. Most of 

these trees, 47 out of 61, were in the 21 to 23 

inches d.b.h. range. About two to four more 

yellow-poplars in each d.b.h. class from 7 to 18 

inches were present on igneous rocks than on sedimentary rocks. Although the numbers of trees per 

acre differed significantly by rock class (table 2). 

chi-square analysis indicated no significant difference in the proportion of trees in diameter 

classes by rock class for either yellow-poplar, 

miscellaneous species,or the total stand. 

Diameter distribution of the tree populations 

was similar on both rock classes. Yellow-poplar 

and miscellaneous species were unimodal at the 14 

and 6 inches d.b.h. classes, respectively. The 

median diameter was 12.5 inches for yellow-poplar 

and 7.5 inches for miscellaneous species. 

Comparison with Standard Distribution 

In table 6, d.b.h. distributions from this 

study are compared with similar data presented by 

McGee and Della-Bianca (1967), which apply to predominantly yellow-poplar stands in the Southern 

Appalachian Mountains from north Georgia to 

Virginia. Two test stands on each rock class were 

synthesized from the sample plot data for comparison with published data. The mean d.b.h. distribution of each test stand was determined from data 

for four plots with the same site index class, age 

class, and tree density class. Because the mean 

tree density of the four samples in each group did 

not exactly match a published stocking value, the 

number of trees in each diameter class was expressed as a percentage of the total number of 

trees per acre. Thus, each of the four test 

stands has a bimodal diameter distribution, indicating the presence of an understory with a mean 

diameter of from 6 to 8 inches. 

Results of the chi-square analysis indicated 

no real differences between the yellow-poplar 

stands on igneous rocks in the study and the published results. Both test stands had slightly 

more trees in the smaller diameter classes. For 

example, the median d.b.h. was about 10 inches 

for the synthesized stand with 120 site index and 

50 years of age. In comparison, half of the trees 

were I1 inches or smaller in the published distribution. Mean stand basal area was only about 4 

percent less than the'published values. 

The diameter distribution differed significantly from published results for the two synthesized stands on sedimentary rocks. In both test 

stands, more trees of smaller diameter and fewer 

large trees were present compared with published 

data. For the stands with 120 site index and age 

50, the median d.b.h. classes were separated by 

almost two diameter classes. The test and pub- 
lished diameter distributions differed even more 

for the site index 130 comparison, where the median stand d.b.h, classes were separated by five 

size classes. Mean basal area was 17 to 41 percent less than expected. 

S AND COHCLUSIONS 

Characteristics of yellow-poplar stands 

measured at various locations within the Bald 

Mountains of North Carolina were significantly 

related to the geologic rock class. Yellow-poplar 

stands on soils derived from igneous rocks had 

significantly greater tree density and basal area 

than similar stands over sedimentary rocks. In 

comparison with published data, the diameter distribution of yellow-poplar stands on igneous rocks 

was close to the expected ratios. But on sedimentary rocks, the sample stands did not fit the 

predicted diameter distributions. Characteristics 

of stands on sedimentary rocks were similar to 

those of stands 10 to 20 units lower in site index 

on igneous rocks in this study and in comparison 

with published results. In addition to productivity, geologic variables may also provide information on forest management problems associated with 

stand regeneration and species composition. 

Although stands on sedimentary rocks were 

less productive than those on igneous rocks in 

this study, these results do not apply to igneous 

and sedimentary rock units elsewhere because other 

lithologic characteristics such as mineral content, 

texture, and grain size may be quite different. 

Further research on how geologic variables 

influence stand productivity on other sites and for 

different species is recommended. Correlations 

among geologic variables and soil characteristics 

affecting stand characteristics should also be 

studied. 

Table 5.--Distribution of trees on plots dominated by yellow-poplar overstory, by diameter class and rock 

class 

Rock D.b.h. class (inches) 

class 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21+ Total 

.............................. rJumber ~er acre .......................................... 

YELLOW-POPLAR 

Igneous 34698 8 9101112 9 9 7 4 3 3 3 118 

Sedimentary 13 4 5 5 6 7 5 7 8 7 5 4 3 2 2 3 7 7 

MISCELLANEOUS SPECIES 

Igneous 111212107 6 3 4 3 3 2 11 10 0 1 7 7 

Sedimentary 9 15 12 9 6 6 4 4 4 2 1 1 1 1 1 1 1 7 8 

ALL SPECIES 

Igneous 14 16 18 19 15 14 12 14 14 15 11 10 8 5 3 3 4 195 

Sedimentary 1018161411 12 11 9 11 10 8 6 5 4 3 3 4 155 
Table 6.--Mean diameter distribution of natural yellow-poplar stands growing on two classes of rocks in 

Xadison and Haywood Counties, NC, compared with diaaetcr distributions reported by McGec and Della-Bianca 

(1967) 

Data Basal Trees per diameter class (inches) Total 

source area 5 4 7 8 9 10 11 12 13 14 15 16 17 18 19 20 211 trees 

7 

Et'- - ................................... Percent .................................. - No. 

IGNEOUS ROCKS, SITE INDEX 120, AGE 50 

Test 165 971198 6 8 6 9 6 4 4 6 3 2 11 21 1 

Published 172 25788 9 9 8 8 7 7 6 5 5 3 3 0 200 

IGNEOUS ROCKS, SITE INDEX 130, AGE 50 

Test 165 535105 3 411 6 9 9 9 5 5 3 3 5 164 

Published 17 1 13457 7 7 7 8 7 7 7 7 6 6 5 6 150 

SEDIMENTARY ROCKS, SITE INDEX 120, AGE 50 

Test 12 3 581267 61112 4 7 5 3 7 1 2 1 3 154 

Published 149 1.3577 8 8 9 8 8 7 7 7 6 5 3 1 150 

SEDIMENTARY ROCKS, SITE INDEX 130, AGE 60 

Test 131 515898 4 15 5 6 6 6 2 5 5 5 5 143 

Published 2 17 12345 5 6 6 6 6 6 6 6 6 6 620 150 

LITERATURE CITED 

Beck, Donald E. Yellow-poplar site index curves. 

Res. Note SE-180. Asheville, NC: U.S. Department 

of Agriculture, Forest Service, southeast err^ 

Forest Experiment Station; 1962. 2 pp. 

Graves, James B.; Monk, Carl D. A comparison of 

soils and vegetation over marble and schist 

along tributaries to Panther Creek, Stephens 

County, Georgia. Castanea 50(3):146-163; 1985. 

McGee, Charles E.; Della-Bianca, Lino. Diameter 

distributions in natural yellow-poplar stands. 

Res. Pap. SE-25. Asheville, NC: U.S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1967. 7 pp. 

Rohrer, Joseph R. Vegetation pattern and rock type 

in the flora of the Hanging Rock area, North 

Carolina. Castanea 48(3):189-205; 1983. 

Warren, Harry V.; Matheson, Chester R. Some 

relationships between geology and forest growth. 

British Columbia Lumberman 33(6):60-61, 156; 

1949. 

Whiteside, E. P. Some relationships between the 

classification of rocks by geologists and the 

classification of soils by soil scientists. 

Soil Science Society Proceedings 1953:138-142. 
METHODS FOR REFINING GROWTH-SITE INDEX AND ENVIRONMENTAL 

FACTORS RELATIONSHIPS FOR LOBLOLLY PINE ON CERTAIN 

(ABSTRACT) 

Marilyn A. Buford and William H. McKee, ~r.' 

An approach to re1 ati ng site productivity and environmental factors 

based on the assumption that the shape of the height-age profile for a 

site provides as much or more information about tree growth on the site 

than does site index value, has been implemented in the study of 105 

1/4-acre plots. The plots were established in 1980 in natural loblolly 

pine stands on the Santee Experimental Forest in South Carolina, Soil 

chemical and physical analyses were performed, understory vegetation was 

mapped and tallied, overstory vegetation was mapped and measured, and 

stem analysis was performed on two dominant-condominant trees from each 

plot. 

The goal of this analysis was to develop a methodol ogy for quantifying 

the shape of the height-age profiles and for relating this shape to 

environmental factors. Using stem analysis data, two dominant-codominant 

trees from each plot were placed in site index groups with group members 

having equal heights at age 50, Within each site index group, height-age 

profile shapes developed from stem analysis were compared and departures 

from expected shapes were noted. Expected shapes were determined from 

the drainage class, Results indicate that for a given site index value, 

departures from expected growth patterns can be understood and predicted 

primarily from soil phosphorous levels for the soi 1 series investigated. 

The methodol ogy developed forms a basi s for the - devel opment of a concept 

of tree growth and site quality relationships that is portable. 

' paper presented at Fourth Bienni a1 Southern 

Si lvicul tural Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

'southeastern Forest Experiment Station, 

Forestry Sciences Laboratory, 2730 Savannah Hwy., 

Charleston, South Carolina. 
RESPONSE OF GHERRYBmX. OAK FMILIES TO 

1 i DIFFERENT SOIL-SITE CONDITIONS2/ Stephen G. Dicke and John R. ToliverAbstract.--Survival and height growth in a five-year-old 

progeny test of cherrybark oak were studied to determine how 

slight differences in soils can influence performance. 

Cherrybark oak survival at age five decreased from 90 to 73 

percent and height dropped from 9.9 to 7.3 feet respectively 

when the soil series changed from a somewhat poorly drained 

Dundee soil to a poorly drained Baldwin. Poor soil aeration 

reduced survival the most during year one while the major 

reduction in height growth rate occurred after age three. The 

performance of all families was worse on the poorer drained 

soil. However, one family was the tallest and best survivor on 

both soils. Therefore, both growth and tolerance to poor soil 

aeration can be increased by selection thereby making cherrybark 

oak a more viable regeneration investment in the bot.tomlands, 

INTRODUCTION 

Cherrybark oak (~uercus falcata var 

pagodifolia Ell.) is the highest quality 

bottomland red oak in the lower Mississippi 

River delta region. But in 1984 cherrybark oak 

made up only one percent of the growing stock 

for this delta region {Rosson and Bertelson 

1986). Therefore, the relative value of 

cherrybark oak should increase in the future. 

Today many agronomic crops are only 

marginally profitable in the Delta. One 

alternative is conversion of these agricultural 

lands to high quality hardwood stands. This 

will normally require an artificial regeneration 

method such as planting. Therefore, performance 

of cherrybark oak needs to be evaluated in 

plantat ions before it can be recommended for 

reforestation. 

Excessive water and poor aeration are site 

factors that can be detrimental to cherrybark 

oak growth and survival, but little is known 

about the magnitude of the influence. The 

objectives of this paper were to determine: (1) 

the influence of two slightly different soil 

series on cherrybark oak survival and height 

growth during the first five years of 

1/ Paper presented at Fourth Biennial 

southern Silvicultural Research Conference, 

Atlanta, Georgia, November 4-6, 1986. 

- 2/ Instructor and Associate Professor of 

Forestry, School of Forestry, Wildlife, and 

Fisheries, Louisiana Agricultural Experiment 

Station, Louisiana State University Agricultural 

Center, Baton Rouge, LA. 

plantation development and (2) if family 

selection can overcome any of the negative 

aspects associated with poor soil drainage. 

MATERIALS AND METHODS 

Site Description 

The study was located on an old field in 

the Thistlethwaite Game Management Area, St. 

Landry Parish, Louisiana, The site was a 

natural levee of Bayou k'auksba in the Lower 

Mississippi River Alluvial Floodplain. 

Agronomic crops had been grown on the site for 

approximately twenty years with soybeans being 

produced the year before planting. 

Half of the plantation was established on 

the crest of the levee and the other half on the 

middle to lower slope away from the bayou. The 

levee crest Gas 1-2 feet higher in ejevation 

than the lower slope thus creating differen~~s 

in soils and drainage. A somewhat poorly 

drained Dundee soil series; a fine-silty, mixed, 

thermic Aeric Ochraqualf, was located on the 

crest of the levee (Soil Conservation Service 

1986). The poorly drained Baldwin series, a 

fine, montmorillonitic, thermic Vertic 

Ochraqualf, was located on the middle to lower 

slope of the levee away from the bayou. Both 

soils had silty clay loam textures to 20 inches 

in depth but the Dundee had a slightly lower 

clay content (Faulkner 1985). This coarser 

texture gave the Dundee soil a faster 

permeability than the Baldwin, .5 verus .05 

inches per hour respectively (Soil Conservation 

Service 1986). The Dundee soil was better 
drained because of its higher topographic 

position and better aerated texture, whereas the 

Baldwin tended to pond for short periods of time 

after heavy rainfalls. 

Faulkner (1985) found the Dundee soil to 

have more available water at field capacity and 

more extractable phosphorus than the Baldwin 

(Table 1). The Baldwin was better for most 

other soil characteristics measured. Both soils 

were considered good for cherrybark oak. The 

estimated site index at age 50 years was 99 feet 

for the Dundee soil and 94 feet for the Baldwin. 

These estimates were based on site conditions as 

per Baker and Broadfoot's 11979) method of site 

evaluation. 

Table 1. Physical and chemical properties of 

the A and B horizons for a Dundee and Baldwin 

soil located in St. Landry Parish, Louisiana 

(From Faulkner 1985). 

Soil horizon 1 

A . . BP -2 Soil 

property Dund Bald Dund Bald 

---..- Physical properties - - - - - 

Texture S~CL~' SiCL SiCL Sic1 

Bulk Density (g/cc) 1.33 1.27 1.38 1.31 

Field Capacity (%) 3 2 33 3 2 35 

Wilting Point (2) 16 19 20 23 

Available Water (2) 16 14 12 12 

Chemical Properties - - - - - 

PW 5.0 5.4 5.1 5.6 

Organic Matter (2) 1.4 1.8 0.5 1.4 

Extractable P (ppm) 63 22 107 15 

Extractable K (ppm) 201 229 221 287 

Extractable Ca (pprn) 3080 3704 3137 3845 

Extractable Mg (ppm) 634 870 705 960 

- l/Ap = plow layer (0-10 inches) and 

B2 = subsoil (10-20 inches). 

~'S~CI = silty clay loam. 

Plantation Description 

One-year-old seedlings were planted on 10-x 

10-foot spacing on February 10, 1979. No site 

preparation was done since the site was in 

soybean stubble and free of weeds. Seedlings 

were provided by the Texas Forest Service, a 

cooperator in the Western Gulf Hardwood Tree 

Improvement Program. Twenty-four open-pollinated families from six seed sources were 

evaluated in this plantation. Thirteen families 

were from two seed sources in Arkansas, eight 

families were from two sources in Texas, one 

family was from Mississippi and two families 

were from a nearby stand in the Thistlethwaite 

Game Management Area. Weeds were controlled the 

first two years by discing between trees and 

spraying a foliar active systemic herbicide 

around the trees. 

Study Design and Measurements 

Half of the trees were planted on the 

Dundee soil series while the other half were on 

the Baldwin. Five replications were nested 

within each soil. Four seedlings were planted 

in a row plot for each family within each 

replication. Seedling survival was evaluated at 

1, 3, and 5 years after planting. Total height 

was measured at ages 3 and 5 and diameter at 

breast height was measured at age 5. 

Differences among soils and families were 

tested for significance using analysis of 

variance at the alpha = .05 level. Means were 

separated using Duncan's multiple range test. 

RESULTS AND DISCUSSION 

Response to Soils 

Survival 

Survival averaged 82 percent at age five. 

Trees on the poorly drained Baldwin soil had 17 

percent less survival than those on the Dundee 

(Table 2). This was probably a result of poorer 

aeration and drainage in the Baldwin. The 

difference in mortality rate between the two 

soils was the greatest the first year. Fifteen 

percent of the mortality on the Baldwin soil 

occurred the first year compared to only 6.7 

percent on the Dundee. The mortality rate on 

both soils decreased considerably after the 

first year (Table 2). Therefore, poor soil 

aeration appeared to exert a major influence on 

seedling survival the first year but by age four 

had no significant effect. 

Table 2. Mean mortality rate and survival of 

cherrybark oak seedlings during the first 

five years of plantation development on two 

bottomland soils in Louisiana. 

Soils 

Mortality rate 

by age (yrs.) Survival 

0- 1 2 - 3 4-5 age 5 

Dundee 6.7gi 1.6b .10 90a 

Baldwin 15.0a 5.7a .21 73b 

Mean 10.8 3.6 .16 8 2 

 umbers in the same column followed by 

different letters are significantly different at 

alpha = .05. 
Height and Diameter Height and Diameter 

Cherrybark oak averaged 8.7 feet in height 

and 0 * 83 inches in dbh at age five (Table 3). 

Rate of height growth on both soils was 

approximately the same for the first three years 

(1.2 feet + per year). Kowever, after age 3, 

when the trees more than doubled their growth 

rate on both soils, the growth rate difference 

between the Dundee and Baldwin almost tripled. 

Thus, by age 5 there was a 2.6-foot difference 

in height between the trees on the better Dundee 

than those on the Baldwin soil whereas the 

difference was less than 0.9 foot at age 3 

years. 

Family differences were non-significant 

until cherrybark oak made the transition to a 

faster growth rate at age four. Mean heights of 

families at age five ranged from 10.2 to 7.1 

feet and dbh ranged from 1.02 to 0.60 inches 

(Table 4). The four tallest families (best 15 

percent) were all from Polk County, Texas. 

These four families averaged 10 feet in height, 

0.96 inches in dbh and 83 percent survival. Dbh 

was not as useful as height in selection because 

it was a poorer measurement of stand growth. 

About nine percent of the trees had not yet 

reached 4.5 feet in height at age five. 

Table 3. Mean height, height growth, and 

diameter of cherrybark oak during the first 

five years of plantation development on two 

bottomland soils. 

Table 4. Mean height, dbh, and survival of 

cherrybark oak open-pollinated families at 

age five when planted on a bottomland site 

in southcentral Louisiana. 

Height growth Total 

by age (yrs) height DBH 

Soil 0 - 3 4-5 age5 age5 

Seed source 

Count Famil$' Height DBH Survival 

State parish number (ft) (in) (%I 

AR Bradley 812 

814 

8 15 

8 16 

818 

820 

822 

Dundee 1.3aL/ 3.Oa 9.93 1.0a 

Baldwin I.Ob 2.2b 7.3b .63b 

Mean 1.2 2.7 8.7 .83 

LiNumbers in the same column followed by 

different letters are significantly different at 

alpha = .05. 

AR Clark 3 17 

3 19 

323 

324 

325 

Family Variation 327 

Surv iva 1 TX Cass 115 

116 

Mean survival by family over both soils 

ranged from 68 to 98 percent (Table 4). The 

four families highest in overall survival also 

had 90 percent or greater survival on the 

Baldwin soil. One of the tallest families at 

age five #614 from Polk County, TX, had 95 

percent survival on the poorly drained Baldwin 

soil. This indicates family selection can 

increase height growth as well as survival. 

TX Polk 6 14 

616 

618 

619 

620 

622 

MS Wilkinson 411 

However another tall family, #619, was one of 

the worst families in overall survival at 68 

percent (Table 4). On the Baldwin soil family 

619 had only 50 percent survival. But, even 50 

percent strvival may have been adequate for 

proper stand development, Family 619 still 

produced 131 treeslacre greater than eight feet 

in height on the Baldwin soil. This was six 

more trees per acre than the plantation average. 

Thus a family with a combination of good growth 

and poor survival characteristics could be 

selected as good breeding material if that 

family produces a high number of large trees 

(potential crop trees) per acre. 

LA St. Landry 902 

904 

L/Family numbers assigned by the Western Gulf 

Hardwood Tree Improvement Program. 

2i~alues followed by an * are among the top 15 

percent for that characteristic. 

All families performed worse on the Baldwin 

soil but the best families in height on the 

Dundee soil were also the best on the Baldwin. 

The tallest four families on the Dundee were 1.5 

feet greater than the average while on the 
Baldwin they were 0.7 feet taller (Table 5). 

Therefore by selecting the top four families 

about one-fourth of the growth loss on the 

Baldwin soil could be recovered. 

Table 5. Cherrybark oak height at age five for 

the plantation average and top 15 percent 

families on two bottomland soils in Louisiana. 

Total height at ape 5 years 

Plantation Top 15 % 

Soil mean family mean 

---- feet - - - - 

Dundee 9.9 11.5 

Baldwin 7.3 8.0 

Mean 8.7 10.0 

CONCLUSIONS 

Differences in soil drainage and aeration 

exerted a strong influence on early cherrybark 

oak survival and growth. Mortality rate was 

doubled on a poorer drained Baldwin soil 

compared to a Dundee soil. Most of the 

mortality was during the first growing season. 

Height growth was similar on both soils for the 

first three years, but during years four and 

five, height growth was one-third less on the 

Baldwin soil. Thus, by age five, trees on the 

better Dundee soil were 25 percent taller. 

Although there was a loss of 2.6 feet in 

height when the trees were grown on the Baldwin 

soil about one-fourth of this growth could be 

recovered by selecting the best four families. 

Family selection for survival showed even more 

promise, since several families had 90 percent 

survival on the poorly drained Baldwin soil. 

One family was the best in both height and 

survival. Therefore both traits could be 

improved together through family selection. 

LITERATURE CITED 

Baker, J, B. and W. M. Broadfoot. i879, A 

practical field method of site evaluation 

for comercially important southern 

hardwoods, USDA For. Serv. General Tech, 

Report SO-26. So. For. Exp. Stn., New 

Orleans, LA. 51 p, 

Paulkner, P. L. 1985. Genetic variation among 

half-sib families of baldcypress seedlings 

planted on two different sites. Master's 

thesis, School of Forestry, Wildlife, and 

Fisheries, Louisiana State University. 101 

P . 

Rosson, J. F., Jr. and D. F. Bertelson. 1986. 

Forest statistics for south delta Louisiana 

parishes. USDA For. Serv. Resource Bull. 

SO-106. So. For. Exp. Stn., New Orleans, 

LA. 31p. 

Soil Conservation Service. 1986. Soil survey 

of St. Landry Parish, Louisiana. 

Superintendent of Documents, U. S. Govt. 

Printing Office, Washington, D. C. 20402. 

(In print). 

SilviculturemEconomic Relationships 

Moderator: 

George F. Dutrow 

Duke University 

Froduction and Financial Comparisons of 

Uneven-aged and Even-aged Management of Loblolly ?ine2 

James B. I3aker2 

Abstract.--Production and financial comparisons were 

made of two even-aged and two uneven-aged loblolly pine 

(pinus kaeda L,) management systems, In terms of 

production, the even-aged systems--plantation and natural 

stand management--produced the most cubic-foot volume, 

while uneven-aged management with high stocking levels and 

even-aged plantation management produced the most sawlog 

volume. From a financial standpoint, even-aged natural 

stand management generally showed a distinct advantage over 

the other three management systems, surpassing them in net 

present value, benefit-to-cost ratio, and cost efficiency 

of cubic-foot production. Uneven-aged management with high 

stocking levels was the most efficient system in terms of 

saw log production. 

INTRODUCTION 

Past research has demonstrated that loblolly 

pine (Pinus taeda L.) can be regenerated and 

managed under a variety of silvicultural systems 

ranging from uneven-aged (selection) management 

to intensive plantstion culture, But the question 

is often asked, "Which is the best management 

system?" The answer, of course, depends on the 

objectives of the landowner. If the sole purpose 

of land management is the production of merchantable timber products and/or income, then production and financial analyses are required. if the 

purpose of land management includes other amenities, such as wildlife, water, recreation, or 

aesthetics, then the values of these amenities 

must be considered. 

Production and financial comparisons of four 

loblolly pine management systems on average sites 

(site index = 90 feet at 50 years) for the midSouth are provided in this paper. 

'paper presented at Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

2Principal Silviculturist and Project Leader, 

USDA Forest Service, Southern Forest Experiment 

Station, Monticello, AR 71655 

METHODS 

Production and financial compssisons for 

three of the management system s--even-aged 

natural stand and plantation management, and 

uneven-aged management with high stocking 

levels--were based on case studies that have been 

conducted on or near the Crossett Experimental 

Forest in southeastern Arkansas. The comparison 

for the fourth management system was based on a 

simulation of uneven-aged management with reduced 

stocking levels. 

The comparisons were made assuming that all 

four management systems could have been initiated 

on identical 40-acre tracts of land and managed 

for a 50-year period, The management systems 

included two uneven-aged and two even-aged management options. The uneven-aged options represented management with low and high stocking 

levels, while the even-aged options represented 

even-aged natural stand management and plantation 

management. The simulations assumed the following initial stand characteristics: 

-- 85 merchantable pines (4 inches d,b.h. 

and larger) per acre. 

-- 18 sawlog size trees (12 inches d,b.h. 

and larger) per acre. 

-- 36 square feet of pine basal area pek 

acre, 

-- 980 cubic feet of total merchantable 

volume per acre. -- 2,341 board feet (~o~le)3 sawlog volume 

per acre. 

'811 board-foot volumes in this paper are in 

Doyle scale. 
For the two meven-aged systems, the initial 

stand was to be managed under the selection 

system, Growing stock was improved to prescribed 

(low or high) levels, and the stand was harvested 

on a 5-year cutting cycle. 

For the even-aged natural stand system, the 

initial stand was assumed to be a shelterwood 

having adequate pine regeneration established in 

the understory, The overstory (2,341 board feet 

per acre plus all pulpwood) was harvested at the 

beginning of the management period, The regenerated stand was thinned periodically and clearcut at the end of the 50-year period. 

For the even-aged plantation, the initial 

overstory (2,341 board feet per acre plus all 

pulpwood) was clearcut at the beginning of the 

management period. The site was prepared and 

planted to loblolly pine. The stand was thinned 

periodically and clearcut at the end of the 50- 

year period, 

A summary of the four management scenarios 

are presented be low. 

Uneven-aged management schemes : 

(I) Building and maintaining an uneven-aged 

stand at a relatively high stocking level-- 

9,000 board feet of sawlog volume immediately before 5-year cyclic harvest cuts. 

Production and harvest volumes for the 

first 40 years of management are from the 

"Poor Farm Fortytt on the Crossett Experimental Forest (Reynolds and others 1984). 

Values for the last 10 years of management 

were projected based on recent periodic 

increments of the stand. 

(2) Building and maintaining an uneven-aged 

stand at a relatively low stocking level-- 

7,000 board feet of sawlog volume immediately before 5-year cyclic harvest cuts. 

Esti~ates of production and harvest volumes 

were generated using a growth and yield 

model for uneven-aged stands (~arrar and 

others 1984). This scenario allowed for an 

initially understocked stand to reach a 

prescribed full stocking level sooner than 

the other taneven-aged management scheme, 

above, and to carry a lower growing stock 

volume (or investment) throughout the management period. 

Even-aged management schemes : 

(1) Management of a stand that originated 

from natural reproduction obtained from a 

shelterwood reproduction cutting method. The 

overstsry (2,341 board feet of pine sawlogs 

plus all pulpwood) was removed at the beginning of the management period. The regenerated stand was thinned to 85 square feet 

of basal area per acre at 5-year intervals 

beginning at age 20. Production and harvest 

volumes were obtained from a thinned 50- 

year-old natural stand that had been subjected to these treatments (~urton 1980, 

Hurphy and Farrar l985), 

(2) Management of a pine plantation established after clearcutting the 2,341 board 

feet of sawlogs per acre plus all pulpwood 

at the beginning of the management period, 

followed by site preparation and planting, 

The stand was thinned to 85 square feet 

basal area per acre at 5-year intervals 

beginning at age 15. Values for production 

and harvest volumes were obtained from a 

thinned 50-year-old plantation that had been 

subjected to these treatments4. 

RESULTS 

Timber Production 

A summary of stand development, harvest 

cuts, and timber production for the four management systems over the 50-year management period 

is presented in tables 1 through 4, and timber 

production for the four systems is summarized in 

table 5. 

For these case studies, plantation management produced 9 percent more total merchantable 

cubic-foot volume per acre than even-aged natural 

stand management, 44 percent more than unevenaged management with high stocking, and 107 percent more than uneven-aged management with low 

stocking (table 5). In terms of pulpwood or 

fiber production, even-aged management was 

clearly superior to the uneven-aged systems. 

In terms of sawlog production, both unevenaged management with high stocking and plantation 

management produced about 25 percent more boardfoot volume per acre than either uneven-aged 

management with low stocking or even-aged natural 

stand management (table 5). Uneven-aged manage-. 

ment with high stocking levels and plantation 

management averaged about 420 board feet per acre 

per year of saw log growth, while uneven-aged 

management with low stocking and even-aged 

natural stand management averaged only about 340 

board feet. Thus, uneven-aged management with 

high stocking levels and plantation management 

appeared to be superior for saw log production, 

4~ata on file at the Forestry Sciences Laboratory, USDA--Forest Service, Southern Forest 

Experiment Station, Monticello, AR 71655. 
Table 1. 

with hiah stoekina levels over a 50-vear management seriod 

Before Harvest Harvest Residual Stand 

Basal Total Board- Basal Total Board- Basal Total Boardarea rnerch. feet area merch, feet area merch, feet 

Time (ft2) (ft3) (Doyle) (ft2) (ft3) (~oyle) (ft2) (ft3) (Doyle) 

years ------------------ --peracre ------- ------------- 

Residual 60 2 , 393 7,341 

Increase 24 1,413 5 , 000 

Harvest "10 44,484 16,241 

Yield 374 5,897 22,241 

Periodic annual increment 3.5 118 425 

Table 2. 

with low stocking levels over a 50-gear management period 

Before Harvest Harvest Residual Stand 

Basal Total Board- Basal Totai Board- Basal T~tal Boardarea merch. feet area rnerch. feet area merch. feet 

Time (ft2) (ft3) (Doyle) (ft2) (ft3) (Doyle) (ft2) (ft3) (Doyle) 

Residual 60 2 ,647 5 025 

Increase 24 667 2,684 

Harvest 121 3,436 14,951 

Yield 145 49103 17,635 

Periodic mnual increment 2.9 82 352 
Table 3. Characteristics, harvests, and timber production for an even-aged natural loblolly pine 

stand over a 50-year management period 

Before Harvest Harvest Residual Stand 

Basal Total Board- Basal Total Board- Basal Total Boardarea merch. feet area merch. feet area merch. feet 

Time (ft2) (ft3) (Doyle) (ft2) (ft3) (~o~le) (ft2) (ft3) (Doyle) .................... eracre-------------------- 

Residual 0 0 0 

Harvest 317 8,787 18,755 

Yield 281 7 807 16,414 

Mean annual increment 5.6 156 328 

Table 4. Characteristics, harvests, and timber production for an even-aged loblolly pine stand 

plantation over a 50-year management period 

Before Harvest Harvest Residual Stand 

Basal Total. Board- Basal Total Board- Basal Total Boardarea merch. feet area merch. feet area rnerch. feet 

Time (ft2) (ft3) (~oyle) (ft2) (ft3) (Doyle) (ft2) (ft3) (Doyle) 

years --------- ---- -- ----- er acre - - - - - - - - - - - - - - - - - - - - 

Residual 0 0 0 

Harvest 329 9,468 23,297 

Yield 293 8,488 20,956 

Mean annual increment 5.9 1 70 41 9 
Table 5.-- 

Production per acre 

To ta 1 Hean annual 

Tot. merch. Board feet Tot. merch. Board feet 

Even-aged (plantation) 8,488 20 , 956 170 4.1 9 

HS = high stocking; 'S = low stocking. 

Financial Analyses Returns : 

Three different financial analyses were 

performed for each of the management systems, 

using the production values presented in tables 1 

through 4 and the following cost and return 

assumptions: 

(1) Pulpwood stumpage = $15 per cord 

(2) Sawlog stumpage = $150 per thousand 

board feet (~oyle) 

Discount Rate: 7 percent compounded annually 

Costs: 

The methods used for the analyses were: (1 ) Selection management 

(a) Annual management costs = $2 per 

acre 

(b) Supplemental management cost 

(inventory & marking) = $13 per 

acre every 5 years (prior to harvest cut) 

(c) Timber stand improvement (TSI) = 

$45 per acre applied every 10 

years 

(2) Natural even-aged management 

(a) Annual management costs = $2 per 

acre 

(b) Initial TSI = $45 per acre 

(e) Pine release at age 5 = $45 per 

acre 

(d) Prescribed burning = $5 per acre 

every 5 years beginning at age 15 

(e) Supplemental management coat 

(inventory & marking) = $13 per 

acre every 5 years beginning at 

age 20 

(7) Plantation management 

(a) Annual management costs = $2 per 

8Cre 

(b) Site preparation and planting = 

$150 per acre 

(c) Pine release at age 5 = $45 per 

acre 

(d) Prescribed burning = $5 per acre 

every 5 years beginning at age 15 

(e) Supplemental management cost 

(inventory K marking) = $12 per 

acre every 5 years beginning at 

age 15 

(1) Net Present Value (NPV) -- The sum of 

all returns anticipated from a management 

system, discounted back to the present, 

minus the sum of all anticipated costs, also 

discounted to the present. It represents 

the present value of the profit associated 

with the system after repaying all capital 

and interest expenses. Net present value is 

an appropriate analysis in cases were investment capital is not particularly 

limiting or in comparing investments of 

approximately equal size, It is frequently 

used by forest industry firms. 

(2) Benefit-to-Cost Ratio (B-C) -- The discounted value of all returns anticipated 

from a management system divided by the 

discounted value of all anticipated costs. 

Thus B-C represents the present value of the 

return per dollar invested in the system, or 

its economic efficiency. It is appropriate 

in eases where capital is limiting, as for 

example with private nonindustrial landowners, or in com2aring investments of unequal amount, 

(3) Cost Efficiency -- The output or yield 

expected from a management system divided by 

the discounted value of ail costs associated 

with the system. Since it estimates physical output per dollar invested in the 

system, cost efficiency can be considered a 

physical analog of B-6. Cost efficiency is 

most appropriate in cases where the owner 

wishes to maximize yield of a particular 

product, for example sawtimber, or where the 
product carries no readily identifiable 

dollar value, 

A summary of the financial analyses is given in 

table 6, 

Over the 50-year management period, the 

even-aged systems had a more favorable NPV at 

$493 to $541 per acre than the uneven-aged 

systems at $314 to $404 per acre, In terms of 

B-C ratios, even-aged natural stand management 

had the advantage due to its low management cost 

with a ratio of 5.4:1. Uneven-aged management 

with low stocking levels and even-aged plantation management provided the lowest B-C ratio 

(3.1 :I ), while uneven-aged management with high 

stocking levels was intermediate with a ratio 

of 3.7: 1. 

When cost efficiency was considered, evenaged natural stand management was more efficient 

in terms of total merchantable cubic-foot production with about 64 cubic feet produced per dollar 

spent, In terms of sawlog production, however, 

the selection system with high stocking levels 

was the most efficient, with 143 board feet produced per dollar spent. Plantation management 

and uneven-aged management with low stocking 

levels were the poorest systems in terms of cost 

efficiency. 

SUMMARY AND CONCLUSIONS 

Production comparisons of two even-aged and 

two uneven-aged management systems for loblolly 

pine over a 50-year management period indicated 

that plantation management maximizes total merchantable cubic-foot volume production. The 

greatest amount of sawlog volume was produced 

using either uneven-aged management with high 

stocking levels or plantation management, 

ratio and the highest cost efficiency for fiber 

(cubic-f oot) production, while uneven-aged management with high stocking levels had the highest 

cost efficiency for sawlog production. Where the 

landowner desires the best possible economic 

efficiency, investing in the management system 

with the highest B-C ratio would be financially 

best. Where the owner desired to produce a 

particular output, or product, he should select 

the system with the highest cost efficiency for 

t ha t produc t.5 

The high WV for even-aged plantation management is misleading in that it resulted more 

from the relatively large investment required by 

the system than from its efficiency. The results 

of this comparison indicate that a landowner 

should select this system only if he desires one 

of the noneconomic benefits associated with it-- 

such as maximum total output or production, the 

opportunity to plant superior seedling, or ease of management. 6 

A landowner who used a management system 

with a high efficiency measure, such as B-C ratio 

or cost efficiency, could manage a larger land 

base with the same investment or the same land 

base with a smaller investment. For example, 

even-aged natural stand management and unevenaged management with high stocking levels both 

have very favorable B-C ratios, These combined 

with the systemsf high cost efficiency values for 

either cubic-foot or sawlog production suggest 

that many landowners could enjoy cost savings by 

managing existing stands rather than engaging in 

extensive conversion to plantation culture. .................... 

5~ersonal communication with R. A. Guldin, 

Forest Economist, Southern Forest Experiment 

Station, New Orleans, LA. 

In financial comparisons, the two even-aged 6~ersonal communication with John Greene, 

systems had the most favorable NPV, although at Professor of Forest Economics and Policy, Dept. 

very different investment levels, Even-aged of Forest Resources, University of Arkansas at 

natural stand management had by far the best B-C Monticello, Monticello, AR. 

Table6. Four loblolly pine management system economic parameters for a 

50-year management period at a 7 percent discount rate 

Net 

present Benefit-to-cost Cost ef ficiency2 

Management systeml value ratio Tft3) ( fbm) 

dollarlacre ---- per dollar---- 

Even-aged (plantation) 493 3.13 36.7 90.7 

1 HS = high stocking; LS = low stocking. 

Cost efficiency = total production/total discounted cost. 
LITERATURE CITED 

Burton, J.D. Growth and yield in managed natural 

stands of loblolly and short-leaf pine in 

the West Gulf Coastal Plain, Res, Pap. SO159. New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1980. 23 p. 

Farrar, Robert H.; Nurphy, Paul A.; Wil lett, 

Larry R. Tables for estimating growth and 

yield of uneven-aged stands of loblollyshortleaf pine on average sites in the West 

Gulf Area. Arkansas Agricultural Experiment 

Station Bulletin No. 874. Fayetteville, AR: 

Division of Agriculture, University of 

Arkansas; 1984. 21 p. 

Murphy, Paul A,; Farrar, Robert &, Effects of 

different thinning regimes on growth and 

inventory of 50-year-old loblolly-shortleaf 

pine stands, In: Proceedings of the 3d 

biennial southern silvicultural research 

conference. Eugene Shoulders, ed. 1984 

November 7-8; At1 anta, GA. Gen. Tech, Rep. 

SO-54. Southern Forest Experiment Station, 

New Orleans, LA: 1985. p. 241-246. 

Reynolds, R.R.; Baker, James B,; Ku, Timothy T. 

Four decades of selection management on the 

Crossett Farm Forestry Forties. Arkansas 

Agricultural Experiment Station Bulletin No. 

872, Fayetteville, AR: Division of Agriculture, University of Arkansas; 1984, 43 p. 
ECONOMIC ASSESSMENT OF CHEMICAL VERSUS 

PIECWICAL SITE PREPARATION' 

Clifford A. Hichan, Walter C. Anderson, and Richard W. Guldin 2 

Abstract.--The economics of chemical site preparation re'lative to three intensities of mechanical site preparation were 

evaluated for a variety of site conditions. Specifically, the 

investment returns obtainable from unthinned loblolly pine plantations grown over rotations of 20, 25, and 30 years were estimated and compared for all combinations of treatment method and 

site condition. Chemical site preparation proved to be the most 

cost-effective technique when the residual hardwood stocking was 

moderate to heavy and the "best" or "expected" treatment outcomes 

were presumed to occur. Where there was little or no hardwood 

competition, the heavy mechanical procedure was superior. This 

technique also gave the highest returns for all site conditions 

envisioned when the "worst" treatment outcomes were assumed. 

Keywords: Hexazinone, cost effectiveness, loblolly pine. 

The 1979 Timber Assessment concluded that the 

Nation's greatest opportunities for increasing 

timber growth are located in the South (USDA 

1982). The region contains as many as 52.1 

million acres of existing stands, which -- because they are either at or past maturity, or 

suffer from poor species composition -- would 

benefft from conversion to young, vigorous pine 

plantations (Dutrow and Kaiser 1984). Experience has shown, however, that it will not be easy 

to capitalize on these investment opportunities. 

On cutover areas of the? type envisioned, large 

expenditures for site preparation may be needed 

to ensure adequate control of the inevitable competition from both hardwood sprouts and herbaceous weeds. 

Competing vegetation in pine plantations has 

traditionally been controlled by fire, mechanical means, or both procedures combined. These 

alternatives, however, have not proved totally 

satisfactory. Use of fire is limited by weather 

conditions, and hardwood brush is sometimes 

poorly controlled (Kushmaul 1978). Use of 

mechanical means tends to be expensive, and significant site disturbance sometimes results 

(Guldin 19838; Kushmaul 1978), Because of these 

deficiencies, chemical site preparation has been 

the object of considerable attention in recent 

years. Research has clearly shown that chemicals, 

'presented at Fourth Biennial Southern Silvicultural Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

'principal Economist and Volunteer Principal 

Economist, Southern Forest Experiment Station, 

Forest Service, U.S. Department of Agriculture, 

New Orleans, LA 70113; Assessment Coordinator, RPA 

Staff, U.S. Department of Agriculture, Forest 

Service, Washington, D.C. 20013. 

when properly applied, are capable of providing 

effective competition control (Glover and Dickens 

1986). Less clear is how herweides compare to 

other treatment options from an economic standpoint. 

The objective of this study was to evaluate 

the economics of using chemical as opposed to 

mechanical means to prepare cutover sites for 

planting. The analysis was conducted under 

the premise that hexazinone , trade n me Velpap, 3 would be the speeifie chemical used. However, 

because our current understanding of the relative effectiveness of various site preparation 

herbicides does not allow us to accurately distinguish between them, the results are probably 

indicative of how chemical treatments in general 

compare to mechanical procedures. 

APPROACH 

The evaluation was structured around three baslc 

steps. First, a broad range of possible treatment 

opportunities -- i.e., site conditions -- were 

hypothesized- Secondly, a series of alternative 

treatment options -- i.e., site preparation 

methods -- were defined. Finally, investment 

returns were eaLculated for all treatment opportunity and treatment option combinations. These 

returns were predicated on the assumption that 

loblolly pine (pinus - -- taeda L.) plantations, established at an leitlal denslty of 700 trees per 

acre, would be grown unthlnned over rotations of 

20, 25, or 30 years, 

3~rade nanes are used for the reader's information and convenience. $heir use in this study 

does not constitute official endorsement or 

approval by the U.S. Department of Agriculture to 

the exclusion of other suitable products. 
The treatment opportunities that were recognized 

in the analysis consisted of all combinations of 

three post-harvest residual hardwood stocking 

levels and three site productivity classes. The 

three possible post-harvest residual hardwood 

stocking levels were : 

- Light: 10 percent of the preceding standOs 

total basal area (BA) in unmerchantable hardwoods. 

- Moderate: 30 percent of the preceding stand's 

total BA in unmerchantable hardwoods. 

- Heavy: 50 percent of the preceding stand's 

total BA in unmerchantable hardwoods. 

The three site productivity classes corresponded 

to site indicies of 50, 60, and 70 feet at a base 

age of 25 years. 

Treatment O~tions 

The treatment options that were recognized in 

the analysis consisted of three intensities of 

mechanical treatment and one intensity of chemical treatment. The specific treatment methods 

and their associated site preparation practices 

were : 

- Light mechanical: chop and burn. 

- Moderate mechanical: shear, pile, and burn 

piles. 

- Heavy mechanical: shear, pile, burn piles, and 

disk. 

- Chemical: aerial application of hexazinone at 

label rates followed by burning, 

Calculation of Investment Returns 

The investment returns that would be obtained, 

given each combination of treatment opportunity 

and method, were estimated using a computer model 

called ECONHDWD.~ This model predicts the survival, growth, and yield of unthinned loblolly pine 

plantations under various levels of hardwood competition and transforms the projected outputs into 

measures of economic performance. Although the 

program will do investment analyses in either real 

or current value terms, for purposes of this study 

the real value method was employed. In addition, 

of the several decision criteria the model computes, only the internal rate of return (IRR) was 

considered. 

To utilize ECONHDWD, several types of input data 

were required. Specifically, for each combination 

of treatment method and treatment opportunity, it 

was necessary to provide estimates of (1) the 

proportion of each plantation's total BA that 

would be in hardwoods at the time of crown 

4~prinz, Peter T.; Burkhart, Harold E.; Greber, 

Brian J. A model for the economic assessment of 

reducing hardwood competition in loblolly pine 

plantations. (mimeographed). No date. [Available from Department of Forest Science, Texas A&M 

University, College Station, TX]. 

closure; (2) the site preparation, planting, and 

other management costs that would be incurred; and 

(3) the stumpage price5 that would be received at 

harvest for both sawthber and pulpwood products. 

Of these data requirements, the first was by far 

the most difficult to satisfy. 

Basal Area Percentages 

The desired BA percentages were derived through 

a four step process, each component of which 

merits explanation, as follows: 

Step 1. -- To estimate, for each of the hypothesized treatment opportunitiest how many square 

feet of hardwood BA would be left on site 

following removal of the preceding stand. This 

was accomplished by multiplying the pre-assigned 

residual hardwood stocking proportions for each 

site -- i.e., 10, 30, or 50 percent -- by a corresponding set of expected total BA's. The latter 

were determined with the aid50f data from 

Schumacher and Coile (1960). 

Step 2. -- To estimate, for each of the hypothesized treatment opportunities, how many square 

feet of hardwood BA would be left on site 

following application of specific site preparation procedures. This was accomplished by constructing -- based on published research findings 

as well as expert opinion -- the subjective probability distributions shown in table 1. These 

distributions define the assumed levels of hardwood control that would result from using each of 

the tr atment options being recognized in the 

study .' The distributions were employed to 

specify three of the many possible outcomes that 

could conceivably result from application of a 

particular site preparation technique to a particular site. These outcomes were designated as 

the "worst" -- i.e., least favorable; "expected" 

-- i.e., m st likely; and "best" -- i-e., most 

favorable. 9 

5~chumacher and Coile data were used to ascertain, for sites in each of the assumed productivity classes, how many square feet of BA would 

occur in a 35-year-old fully-stocked natural 

stand of loblolly pine. These preliminary figures 

were then adjusted to account for the fact that 

total BA would probably decline as the proportion 

of the stand in hardwoods increased. Per a re (Z reductions were made at the rate of 1.18 ft for 

each percentage point increase in the hardwood 

component. 

6~he probabilities of non-control , which were 

the actual values needed, were determined by 

deducting the probabilities of control from 1.0. 

7~or each site preparation procedure, the 

"expected" outcome was computed by (1) multiplying 

the potential levels of hardwood control by their 

corresponding probabilities of occurrence and (2) 

aggregating the products. The "best" and '@worst" 

outcomes, as their names imply, corresponded to 

the upper and lower tails of the various probability distributions. 
Table 1. -- Effectiveness of alternative site preparation methods in controlling hardwoods 

Hardwoods controlled (percent) 

Treatment method 

------------ (probability of occurrence) - - - - - - - - - - - - 

Hechanical 

Light 

Moderate 

Heavy 

Chemical (hexazinone) 

Step 3. -- To develop, for each combination of of a growth and yield model called USLYCOWG 

treatment method and opportunity, preliminary (Feduccia and others 1979). 

estimates of the proportions of total plantation 

BA that would be in hardwoods at the time of crown Step 4. -- Finally, to distribute the prelimiclosure. This was accomplished by expressing the nary BA percentages developed in step 3 to a 

BA figures from step 2 as percentages of the total selected group of scientists who have been engaged 

BA's that the plantations were expected to have at In vegetative control research for evaluation. 

age 10, gn assumed proxy for the time of crown Based on the responses obtained, some of the iniclosure. The latter-were estimated with the aid tial figures were adjusted, thereby giving rise to 

Table 2. -- Proportion of hardwood basal area in plantationL at age 10 for worst, best, and 

expected treatment outcomes, by treatment method and opportunlty 

Treatment opportunity and outcome 

Light residual Moderate residual Heavy residual 

Treatment method hardwoods hardwoods hardwoods 

Worst Expected Best Worst Expected Best Worst Expected Best 

-----------I-- (percent hardwood) - - - - - - - - - - - - - - 

Mechanical 

Light 13 9 5 31 22 13 39 2 8 17 

Moderate 8 5 3 20 13 7 25 17 8 

H@av y 5 2 a 13 6 2 17 a 3 

Chemical (hexazinone) 9 4 I 22 10 2 28 13 3 

l~ased on 700 trees planted per acre. 

8Though this approach makes sense mathemat ically, in reality its reasonableness is uncertain. 

When an area is site-prepared, at least by mechanical means, the BA of uncontrolled hardwoods will 

drop to essentially nothing immediately after 

treatment. Sometime later a hardwood component 

may emerge in the new stand through resprouting, 

but the nature of the relationship, if any, 

between the BA of these sprouts and the hardwood 

BA that existed before treatment is unclear. The 

number and distribution of the former stems is 

probably more important than their BA. 

the final estimates shown in table 2. Note that 

in constructing this table, weighted averages of 

the SA percentages for site 50, 60, and 70 lands 

were computed. The weights used in this averaging 

process were '20, .75, and .05, respectively. 

These weights reflect, for the Midsouth, the acreage distribution of loblolly pine stands by site 

productivity class (Feduccia and others 1979). 

Management Costs 

The site preparation costs that were used in the 

study are shown in table 3. The costs of mechanical site preparation were compiled using data from 
Table 3. -- Site preparation costs, by treatment method and opportunity 

Treatment opportunity 

Treataent method Light 

residual 

hardwoods 

Moderate 

residual 

hardwoods 

Heavy 

residual 

hardwoods 

------------ (dollarsfacre) - - - - - - - - - - 

Mechanical 

Light 

Moderate 

Heavy 

Chemical (hexazinone) 

Straka and Watson (1985), Guldin (1983a), and 

Fitzgerald (1985); the costs of chemical site 

preparation were determined by contacting several 

firms engaged in the aerial application of hexazinone; and the costs of burning were obtained, 

once again, from Straka and Watson (1985). Note 

that the costs of the mechanical treatments, 

unlike those of the chemical treatment, were 

allowed to vary with the assumed level of residual 

hardwood stocking, The costs of the chemical 

treatment were held constant because on coarse 

soils, such as the sandy loams where loblolly pine 

is typically grown, the recommended application 

rate for hexazinone (2 gallons, or 4 pounds of 

active ingredient per acre) does not change with 

the volume of hardwoods occupying the site. 

The planting costs that were used in the study 

are shown in table 4. Planting costs, exclusive 

of seedlings, were taken from Straka and Watson 

(1985) and GuLdin (1983b). It was assumed that 

these costs would vary with the amount of woody 

vegetation remaining on the site at the time of 

planting. Seedling costs, which as noted earlier 

were based on an assumed planting density of 700 

trees per acre, were set at $17.50 per acre. This 

value was derived by using data from both Guldin 

(1983b) and the most recent seedling cost survey 

published in Forest Farmer magazine (Forest 

Farmers Association 1985). 

The only other expenditure that was recognized 

in the analysis was an annual administrative 

expense of $3.50 per acre. This amount was 

intended to reflect the costs of such things as 

property taxes; boundary maintenance; road maintenance; and fire, insect, and disease control. 

Stumpage Prices 

On the income side sf the ledger, sturnpage 

prices for the two types of timber outputs that 

were recognized in the study -- i.e., sawtimber 

and pulpwood -- were taken from Timber Mart 

Table 4. -- Planting costsL, by treatment method and opportunity. 

Treatment opportunity 

Treatment method Light 

residual 

hardwoods 

Moderate 

residual 

hardwoods 

Neavy 

residual 

hardwoods 

Mechanical 

Light 

Moderate 

Heavy 

Cheaieal (hexazinone) 

'~ncludes $17.50/acre for seedlings. 
~outh.~ Sawtimber was valued at $150.00 per thousand board feet (Scribner). Pulpwood was valued 

at $17.00 per standard cord. To ensure consistency throughout the analysis, all prices and 

costs were expressed in terms of constant 1984 

dollars. Furthemore, no real cost or price 

changes were considered in projecting future 

receipts and expenditures. 

RESULTS 

The data generated by the study comprised a set 

of 324 IRR figures. These figures showed the 

estimated investment returns associated with each 

combination of the nine treatment opportunities, 

four treatment methods, three treatment outcomes, 

and three rotation lengths that were recognized in 

the analysis. Although these values could have 

been employed to evaluate the mechanical techniques relative to one another, or to determine 

under what conditions site preparation is profitable, they were used only to draw comparisons 

between the various mechanical options and the 

chemical option. 

Because the choice of a site preparation procedure is often made on the basis of the amount of 

hardwood competition to be controlled, the study 

results are presented by treatment opportunity. 

Light Residual Hardwood Stocking 

On sites where the residual hardwood stocking 

was no more than 10 percent of the preceding 

stand's total BA, the chemical treatment was 

either inferior to, or at least no better than, 

the mechanical site preparation techniques (table 

5). This relationship was consistent over all the 

treatment outcome, site index, and rotation age 

combinations evaluated. The principal reason for 

the relatively poor showing of the chemical option 

seems to be that this procedure, as defined for 

purposes of this study, has no cost advantage over 

the mechanical means when applied to such sites. 

Indeed, as a review of tables 3 and 4 shows, if 

the residual hardwood stocking is light -- use of 

hexazinone is the most expensive practice that can 

be employed. 

Moderate Residual Hardwood Stocking 

On areas where the residual hardwood stocking 

was no more than 30 percent of the preceding 

stand's total BA, broadcast applications of hexazinone were the most profitable method of site 

preparation as bong as the "expected" or "best" 

treatment outcomes were presumed to occur. This 

relationship was consistent over all the site 

index and rotation age combinations evaluated 

(table 6). However, when it was assumed that 

the "worst" treatment outcomes would materialize, 

the heavy mechanical option emerged as the 

preferred method of treatment. The relatively 

'published monthly by F. W. Norris; P. 0. Box 

1278; Highlands, NC 28741. 

poorer showing of the chemical alternative in 

this worst case scenario L ectly traceable to 

the g~cater uncertafntiec were assumed to be 

associated wlth this proce As was shown in 

table 1, if it is presuorted that the "worst" possible outcomes will occur, the implication is 

that the application of chemicals will control 

only 50 percent sf the hardwoods on the site to 

be treated. 

Weavy Resf dual Harbaood Stocking 

Turning finally to sites where the residual 

hardwood stocking was as much as 50 percent of 

the preceding stand's total BA, the results were 

essentially identical to those for the moderate 

residual hardwood case (table 7). When it was 

assumed that the "expected" or "best" treatment 

outcomes would occur, the broadcast application 

of hexazinone was the most profitable site preparation practice for all c binations of site 

index and rotation length .p8 This is largely 

attributable to the substantial cost advantages 

that this method of treatment has over all but 

the light mechanical treatment when applied to 

such sites (see tables 3 and 4). When the 

"worst" possible outcomes were presumed to 

materialize, the heavy olechanical technique was 

once again the most suitable site preparation 

procedure. As before, the worst case scenario's 

relatively unfavorable ranking of the chemical 

option is traceable to the greater uncertainty 

that was assumed to be associated with this 

alternative. 

Conclusions 

The results of this analysis suggest that the 

aerial applieation of hexazinone at label rates 

will normally be the most cost effective way of 

preparing cutover sites with a moderate or heavy 

residual stocking of hardwoods. On sites where 

there is little hardwood competition, mechanical 

methods should usually be employed. The principal 

exceptions to these generalizations occur under 

the relatively pessimistic assumptions of the 

worst case scenario. In these instances, the 

heavy mechanical technique, because of its dependable effectiveness, is typically the preferred 

procedure. 

DISCUSSION 

The preceding findings, for at least two reasons, must be interpreted and acted upon with caution. The first reason pertains to the limited 

''AS a point of clarification, for any investment to be judged worthwhile, including those 

involving site preparation activities, it is not 

sufficient that the returns be positive -- they 

must also exceed the investor's "cost of capital." 

The latter is generally determined by either (I) 

the rate of earnings obtainable from the next best 

use of the investor's funds or (2) the rate at 

which the investor can borrow. 
Table 5. -- Rates of return for sites with light residual hardwoods when expected, 

worst, and best treatment outcomes result from various treatment 

methods, by site index and rotation length 

Treatment outcome and site index 1 

Expected worst Best Treatment method 

20-YEAR ROTATION 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

25-YEAR ROTATION 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

30-YEAR ROTATION 

l~iven base age of 25 years. 

'indicates negative IRR. 

amount of information upon which the analysis was 

based. The second reason concerns the built-in 

limitations that were imposed on the study. 

Regarding the informational deficiencies, the 

principal problem was the scarcity of data on probable stand growth responses to chemical site 

preparation treatments. Though the literature 

contains numerous reports of chemical pine release 

studies, only a few investigations involving the 

use of chemicals for site preparation purposes 

have been published, and most of those are less 

than 5 years old. Several researchers considered 

to be among the most knowledgeable about chemical 

site preparation in the South were contacted in 

an effort to supplement the extremely limited 

amount of reported data, but few were willing to 

provide judgemental estimates of the stand growth 

responses that were needed for the study. This 

lack of either solid measurement data or informed 

judgements explains why 1RR"s were calculated not 

only for the "expected" but also for the "best" 

and "worst" treatment outcomes. These calculations made it possible to define the range of 

possible results and provided insights into the 

reliability of the findings for the "expected" 

treatment outcomes. 

Regarding the limitations that were imposed on 

the study, two of them are probably of sufficient 

importance to be stressed. The first restriction 

was that only one herbicide -- hexazinone -- and 

only one application method -- aerial spraying by 

helicopter -- were considered. Although several 

chemicals are often applied during the course of 

an operation to achieve maximum effectiveness, 
Table 6. -- Rates of return for sites with moderate residual hardwoods when 

expected, worst, and best treatment outcomes result from various treat 

ment methods, by site index and rotation length 

Treatment outcome and site index1 

Expected Worst Best 

Treatment method 

50 60 70 50 60 70 50 60 70 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

20-YEAR ROTATION 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

25-YEAR ROTATION 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

30-YEAR ROTATION 

'~iven base age of 25 years. 

%dicates negative IBR. 

such measures were not included in the analysis 

because of their prescriptive nature and the lack 

of adequate response information. Alternative 

delivery sygtems were not evaluated to keep the 

number of required fieancial calculations within 

reasonable bounds. The second restriction was 

that only unthinned stands grown over rotations of 

20, 25, or 30 years were considered. Though prudent forest managers will normally thin stands to 

maintain any growth gains achieved through site 

preparation, this additional practice was not 

included in the analysis for fear of confounding 

the site preparation and thinning responses. 

Despite its shortcomings, the study should prove 

helpful to forest managers facing site preparatgon 

decisions. The basic analytical. approach is 

sound, even though some of the input data may be 

subject to challenge. This being the case, the 

evaluations can be redone using whatever input 

values are deemed most appropriate. Over time, as 

the statistically designed field studies now in 

place begin to provide additional information on 

how stands respond to site preparation by all 

means, it will be possible to make more reliable 

comparisons between chemical and mechanical treatments. 
Table 7. -- Rates of return for sites with heavy residual hardwoods when expected, 

worst, and best treatment outcomes result from various treatment 

methods, by site index and rotation length 

Treatment outcome and site index1 

Expected Worst Best 

Treatment method 

5 0 60 70 50 60 70 50 60 70 

20-YEAR ROTATION 

Mechanical 

Light --2 -- 2.5 -- -- - - -- 2.4 6.5 

Moderate -- 1.0 5.2 -- -- 2.5 - - 3.6 7.5 

Heavy -- 2.1 6.0 -- -- 3.8 -- 3.2 6.9 

Chemical -- 3.3 7.4 -- -- 2.3 0.1 5.6 9.5 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

25-YEAR ROTATION 

Mechanical 

Light 

Moderate 

Heavy 

Chemical 

30-YEAR ROTATION 

'~iven base age of 25 years. 

'lndieates negative IRR. 

LITERATURE CITED 

Dutrow, George F.; Kaiser, H. Fred. Economic 

opportunities for investments in forest management in the Southern United States. Southern 

Journal of Applied Forestry. 8(2):76-79; 1984. 

Feduccia, D.P.; Dell, T.R.; Mann, W.F., Jr. [and 

others]. Yields of unthinned loblolly pine 

plantations on cutover sites in the West Gulf 

region. Res. Pap. SO-148. Mew Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1979. 88 p. 

Fitzgerald, C.H. Forest herbicide use. In: Proceedings of the symposium on herbicides in 

forestry; 1985 December 12-13; Athens, GA. 

Athens, GA: University of Georgia; 1985: 1-20. 

Forest Farmers Association. Seedlings available 

from state nurseries. Forest Farmer. 45(1): 

18-19; 1985. 

Glover, Glenn R.; Dickens, Dale F. Impact of 

competing vegetation on yield of the southern 

pines. Georgia Forest Res. Pap. 59. Macon, GA: 

Georgia Forestry Commission; 1986. 12 p. 
Guldin, Richard W. Site preparation costs in the 

coastal plain -- an update. Res. Note SO-292. 

New Orleans, LA: U.S. Department of &riculture, 

Forest Service, Southern Forest Experiment Station; 1983a. 3 p. 

Guldin, Richard kJ. Regeneration costs for industrial landowners using hand vs. machine 

planting. Southern Journal of Applied Forestry. 

7(2): 104-108; 19830. 

Kushmaul, R.J. Site preparation for regeneration 

of southern pines: problems and challenges. In: 

Proceedings, 31st annual meeting Southern Keed 

Science Society; 1978 January 17-19; P;ew 

Orleans, LA. Champaign, IL: Southern Weed 

Science Society; 1978: 201-203. 

Schmacher, F.X.; Coile, T.S. Growth and yields of 

natural stands of the southern pines. Durham, 

NC: T.S. Coile, Tne.; 1960. 115 p. 

Straka, T.J.; Watson, W.F. Costs of forestry practices. Forest Farmer. 44(5): 15-22; 1985. 

U.S. Department of Agriculture, Forest Service. An 

analysis of the timber situation in the United 

States 1952-2030. Forest Resour. Rep. 23. 

Washington, DC: U.S. Department of Agriculture, 

Forest Service; 1982. 499 p. 
CXOWTN ARD EGOSONIC COMPARISOS5 OF SELECTEP EATURALLY ANG 

ARTTFICALlY REGEKERATED STASDSi 

?Xihael 1'. Xengak, Davld Fi. ';an Lear, 

Stephen K. Nodine, and Cavid C. Guynn, Jr. 2 

ABSTRACT.--Growth and financial rates of return were compared for 

plantations and naturally regenerated stands of lobloily pine (Pinus 

taeda L.). Analyses of spatial pattern indicated that trees in 

natural stands were dlstribrrted in dense, random clumps, while 

plantations had less dense, more uniform patterns. Cozputer 

simulations predicted that ?&year yields for nztural stands would be 

21.2 cords/acre giving an 11.92 interaal rate of return. Limiting 

seedbed preparation to two burns with natural stands yielded a 16.4% 

internal rate of return. Projected 39-year yields for plantations 

were 28.1 cords/acre, with an 11.0% internal rate of return. Since 

establishment costs of plantations were nearly double those of natural 

stands, these results suggest that small landowners could use natural 

regeneration to lower their initial investment and obtain a higher 

rate of return. 

INTRODUCTIOX 

Escalating costs have prevented many nonindustrial landowners from regenerating harvested 

land back to pine. Hardwood invasion of pine 

sites is increasing. Sheffield (1979) found that 

over 42 percent of all pine types harvested in 

South Carolina between 1966-1378 have reverted to 

oak-pine or hardwood types. 

Natural regeneration of loblolly pine (Pinus 

taeda L.) has been proposed as an alternative to 

plantation establishment for small, nonindustrial 

landowners because it is less costly, more 

aesthetically pleasing, and can yield higher 

financial returns (Williston 1978, Van Lear et 

al. 1983). Much is known about the silvicultural 

methods used to naturally regenerate loblolly 

pine in both the Coastal Plain and the Piedmont 

(Brender 1573, Lvtti 1961, Langdon 1481, Van Lear 

1982). However, relatively few studies have compared growth and economic returns of natural 

stands to that of plantations. Nor have economic 

evaluations of performance of natural and ~lar~ted 

stands been frequently addressed. 

'paper presented at the Southern Siluicoltural 

Research Conference, Atlanta, Georgia, Sov. 4-6, 

1986. 

'~uthors are ?!. T. Kengak, Ph.D. Graduate; U. 

H. Van Lear, Professor; S. K. Kodine, Instructor, 

Extension Forestry; and D. C. Cuynn, Professor, 

Department of Forestry, Clemson University, 

Clemson, South Carolina. 

This paper reports on spatial patterns, growth, 

and projected yields of loblolly pine in plantations and natural stands in the Piedmont of South 

Carolina, and compares rates of return on initial 

investments in regeneration. 

METHODS 

Study Areas 

Twenty-five stands were randomly located on 

medium quality sites in the Piedmont Plateau 

Province of vestern South Carolina in Abbeville, 

Edgefield, Greenwood, NcCormick, and Saluda counties. Stands ranged in age from 2 to 22 years. 

Stands were not thinned and, except for site 

preparation, had no recent history of fire. 

Soils were Ultisols, mainly Udults. Average 

annual temperature in the study counties is 62'F 

and yearly precipitation averages 59 inches (SOAA 

r 9s51, 

Satural regeneration on ten sites was by the 

seed-tree method. Previous stand types were 49- 

to 50-year-old old-field loblolly and shortleaf 

pine (P, echinata). Site preparation consisted 

of choFping residual stems and Logging debris 

followed by broadcast burning. Regeneration was 

rapid foilowing this relatively intense site 

preparation treatment. Because there was no lag 

period in regeneration and because no cost or 

iccomes associated with harvest of seed Crees 

were available, economic analyses on natural 

stands were conducted as if regeneration were by 

clearcutting with seed in place. 
Fifteen plantations were also selected. Site 

preparation was by chopping followed by broadcast 

burning. Plantations were planted with 1-0 

lablofly pine seedlings on a 6 x 10 ft spacing to 

yield an initial density of 726 treeslac. 

Data Collection 

Twenty-five 0.01 ac plots per study site were 

randomly located and sampled for pine tree 

density, height and diameter. Height and DBH of 

the dominant pine in each 0.01 ac plot was 

measured (dominance was defined as the tallest 

tree in the plot). Height and diameter of all 

pines was averaged by stand age. Average height 

and diameter was plotted against age for natural 

and planted stands. Least squares analysis was 

used to fit a straight line to the data. 

Differences in slope of the regression lines was 

used to compare height and diameter growth rates 

between natural and planted stands, Basal area 

was determined on the seven oldest stands by 

measuring DBH on all trees (pine and non-pine) 

within randomly located 0.05 ac circular plots. 

Each of these seven stands was between 13 and 22 

years old. 

Density of pines was measured by counting the 

number of living pines in each 0.01 ac plot. Two 

measures of tree spatial pattern were computed 

using the mean and variance of trees per 0.01 ac 

plot. First, the "coefficient of dispersion" (13) 

(Crieg-Smith 1964:65) was computed as 

D = (Variance/Mean Density). 

A value of D = 1 indicates a random distribution, 

values less than 1 indicate a uniform pattern, 

while values greater than I indicate a clumped 

arrangement (Greig-Smith 1964:66). The second 

measure of spatial pattern, Lloyd's "index of 

crowding", (m*) (Pielou 1977:131) was computed as 

a measure of the mean number of neighbors around 

individual stems in each sample plot. Numerically, crowding is the sum of mean density and 

the index of clumping. Crowding is experienced 

by each individual in the population and depends 

on density (Pielou 1977:131). 

Volume projections and economic forecasts were 

made using the YIELD (version 1.4) software 

package (Hepp 1985) with the assumptions given in 

Table I. Cost estimates are from Moak et al. 

(1983) and are the most recent regionwide figures 

available. 

Table I. Assumptions used in economic comparison of natural 

regeneration and planting of loblolly pine. 

Factor Assumption 

Site Piedmont site - S150 = 67 for natural 

stands and SI = 56 for plantations 2 5 

Rotation 30 years, with no thinnings 

Wood prices 

Site preparation costs 

$14/cd and 4% inflation 

$14O/MBF and 5% inflation 

$67.86/ac single chop 

$7fll/ac burn after chopping 

$53.72/ac planting cost 

$12.50/ac seedling cost 

Ad valorem tax $l.OO/ac/year 

Marginal federal tax bracket 35% 

Capital gains proportion 40% 

Discount rate (be£ ore taxes) 8 % 

Harvest expense 10Z of harvest value 

Reforestation tax credit 10% (up to limit of $10,000 annual 

investment ) 

Amortization period for 

reforestation expenses 

84 months 
RESULTS AND DTSCCSSION density within sample plots was wide with 13 

percent of the 0.01 ac plots having 0 or 1 trees 

Current Stand Conditions and 22 percent of the plots having 20 trees or 

more. A few plots had as many as 70-80 seedDistribution of trees was considerably lings. The index of clumping was high (21.9) and 

different between natural stands and plantations indicated a significant departure from a random 

Fig 1. In natural stands, the range of distribution (r = 243.4, d.f. = 247, P < 0.001). 

m 

'- 6.0 FIi TURAL 0 

A N = 248 

a 5.0 

u 

4.0 

3.0 - 

W 

2.0 a: 

W 

1.0 

0iij4~6789111111i11122;?22:22:jOrOSCCOiC~O+ 

0 12 3 4 5 6 7 8 9 0 12 L 5 e 7 G 5 3414iC.bS.il: 

PINES PER Pi07 

Figure I, Frequency distribution of number of loblolly seedlings on 

0.01 ac plots on natural stands and plantations of loblolly pine in five 

South Carolina Piedmont counties. 
The index of crowding was 34.2. Taken together, (t = 25.3, d.f. = 373, P < 0.001). The index of 

values of clumping and crowding indicate that crowding was 6.9. Plantations begin as an 

these natural stands consisted of dense, randomly ordered arrangement of seedlings, but random 

distributed clumps of trees. Askew (1983) found deaths in the stand contribute to the formation 

similar results for natural loblolly stands aged of occassional clumps of pines. These clumps are 

4 to 29 years in ehe South Carolina Coastal less dense (i.e., less crowded) than in natural 

Plain. stands. 

In plantations, density was less variable with A linear relationship adequately describes 

only 5 percent of the plots having 1 tree or height growth of loblolly pine in both natural 

less. Also, no plots had more than 20 trees. and planted stands during the first 22 years 

The index of clumping was low (1.9) indicating a (Fig. 2). Mean height growth rate of pines in 

significant departure from a random distribution planted stands was 2.5 ft/yr (SE = 0.2 ftlyr), 

HEIGHT PINE 

HEIGHT = -3.94 + 2.54 (AGE) 

HEIGHT = -4.16 + 2.32 (AGE) 

1-1-l-8-t-l- ' I 

0 6 8 10 12 14 16 18 20 22 

STAND AGE (YRS) 

TRT N a+& P 

Figure 2. Average height of dominant pines as a function of age on 

natural and planted loblolly pine stands in ffve South Carolina Piedmont 

counties. 
wbiie i,a natural staili,s it was 1.3 Et/yr merchantable stens (2 4.0 in DBM) were pine and 

= 0 + 14 ft '- -' . Fstimates of ?eight qrowt'h 

rate were not s~gn~ficsntly different (P - 0,8L, 

d.f, - l,i2), Average DBH of dominant pines was 

also plotted against age (Fig, 3). Xean diameter 

gr~wrh rate 2; pires was O,h2 in/yr (SE = 0.06 

iniyr) and 0.34 iniyr (S5 = 0.04 in/yr) for 

plantations and natural stands, respectively. 

Estimates of diameter grcwth rates were not 

significantly different (F = 1.14, d.f, = 1,9). 

There is a trend toward slower growth on natural 

stands that may be related to spatial patterns; 

however, this trend was not statistically 

significant. 

Since basal area and DBN parameters are 

meaningless on young stands, basal area 

14, J percent were non-pine. Total basal area vas 

134.3 ft2/ac with pine comprising 75.2 percent of 

the total. Total basal area in merchantable 

stems was 100.1 ft2/ac, of which 83.6 percent 

was pice. In plantations, 98-8 percent of merchantable trees were pine. Total basal area was 

97.1 ft2/ac, of which 93.8 percent was pine. 

Total merchantable basal area was 80.4 ft2/ac, of 

which 99 percent was pine. 

Projections and Economic Analysis 

Internal rates of return for natural regeneration and plantations, based on assumptions Listed 

in Table I, were calculated after growth and 

yield had been projected to 30 years. We had 

DBH OF DOMINANT PINE 

DIAMETER = -0.40 + 6.45 (AGE) 

R2 - 0.99 

DIAI'IETER = -0.30 + 0.35 (AGE) 

2 F: = 0.98 

STAND AGE 

TRT N ~.-~rd P 

Figure 3. Average diameter of dominant pines as a function of 

age on naturally regenerated and planted loblolly pine stands 

in five South Carolina Piedmont counties. 
intended to model all 7 of the oldest stands; 

however, one plantation was eliminated because 

volunteer seeding produced an atypically high 

density of 900 treesfac at age 13. Therefore, 

the more realistic density of 425 treeslac, which 

characterized the two other plantations, was used 

iathe growth simulation program. Also, two 

natural stands were eliminated because the YIELD 

software requires that natural stands be at least 

20 years old. Thus, our simulations are based on 

two nktural and two planted stands. Stand 

parameters of these stands are shown in Table 2. 

Projected yields at age 30 averaged 21.2 

cords/ae on the two natural stands and 28.1 

cordsfac on 2 plantations. These projections 

were lower than those from other simulation 

programs (Burk and Burkhart 1984, Amateis et al. 

1984). YIELD was selected because, unlike other 

programs, it provides an economic comparison of 

stands in addition to a projection of volume. 

Simulations indicated that plantations would 

out-produce natural stands by nearly 7.0 cdsfac 

over a 30-year rotation. However, since 

establishment costs for plantations were nearly 

double those of natural regeneration, the 

internal rate of return would be similar for both 

methods of regeneration (Table 3). Van Lear 

et al. (1983) suggested that clearcutting with 

seed in place would yield a higher rate of return 

than artificial regeneration, We made a second 

simulation of natural stands using two seed bed 

preparation burns (at a cost of $7.50/ac), rather 

than chop and burn for site preparation, and 

found the IRR to be 16.4 percent, about 

5.4 percent greater than that for plantations. 

SUMMARY AND CQNCLUSIOES 

Growth and yield of natural stands can be 

similar to that of plantations established by the 

same site preparation treatments. Distribution 

of seedlings for natural stands is different from 

that of plantations. Natural stands exhibit more 

clumping and have higher indices of crowding. 

Natural regeneration, when used under appropriate 

conditions, can yield financial returns equal to 

or exceeding returns from plantations. Growth of 

natural stands may be improved if economical ways 

to precommercially thin dense clumps of seedlings 

can be devised. If not properly planned and 

coordinated, the risk of natural regeneration 

failure is greatly increased--a possibility we 

did not include in our analyses. However, the 

methodology of establishing natural regeneration 

is well known, and successful regeneration is 

consistently possible if proper techniques are 

used. 

Table 2. Average current conditions'on two natural regeneration stands 

and two plantations of loblolly pine in the western South Carolina Piedmont. 

Natural Plantation 

Stand parametera N 1 N2 P 1 P2 

Age (yrs) 2 o 2 2 13 18 

Site index (ftlb 6 7 6 7 5 6 50 

Density (treesfac) 309 . 520 425 425 

DBH (in) 5.3 4.7 4.5 6.7 

Height (f t) 37.3 36.0 27.7 34.3 

Pine basal area (ft2/ac) 67.1 101.5 54.7 113.7 

%oblolly pine only 

b~ite Index: age 50 for natural stands, age 25 for plantations 
Table 3, Projected (to age 30) woodflow and financial analysis for two 

natural stands and two plantations of loblolly pine in the western South 

Carolina Piedmont. 

Natural Plantation 

Stand parametera N 1 N2 P 1 P 2 

Density (treeslac) 309 

Height (ft) 56 

Pine basal area (f t2/ac) 9 8 

Sawtimber (MBF/ac) 2.5 

Pulpwood (cdsfac) 13.7 

Total cords (per ac) 19.3 

Regeneration cost ($) 7 5 

Internal rate-of-return (X) 12.0 

a~oblolly pine only 

LITERATURE CITED 

Amateis, R. L., H. E. Burkhart, B. R. Knoebel, 

and P. T. Spring. 1984. Yields and size class 

distribution for unthinned loblolly pine 

plantations on cutover site-prepared lands. 

School of Forestry and Wildlife Resources, VP1 

& SU, Blacksburg, VA. Pub. No. FWS-2-84. 

Askew, G. R. 1983. Two methods for evaluating 

spacing pattern in naturally regenerated 

loblolly pine stands. For. Sci. 29:514-518. 

Brender, E. V. 1973. Silviculture of loblolly 

pine in the Georgia Piedmont. Georgia Forest 

Research Council Report No. 33. 

Burk, T. E. and H. E. Burkhart. 1984. Diameter 

distributions and yields of natural stands of 

loblolly pine. School of Forestry and Wildlife 

Resources, VPI & SU, Blacksburg, VA. Pub. No. 

FWS-1-84. 

Greig-Smith, P. 1964. Quantitative Plant Ecology. (2nd ed.). Butterworths, London. 

256 pp. 

Hepp, T. E. 1985. Users manual for YIELD, 

timber yield forecasting and planning tool, 

Version 1.4. TVA, Norris, TN. 

Langdon, 0. G. 1981. Katural regeneration of 

loblolly pine: A sound strategy for many 

forest landowners. S. Jour. Appl. For. 

5:170-176. 

Lotti, T. 1961. The case for natural regeneration. pp. 16-23 in Proc. 10th Ann. For. Symp. 

LSU Press, Baton Rouge, LA. 

Moak, J. E., W. F. Watson, and M. S. Watson. 

1983. Costs of forestry practices in the 

South. For. Farmer Manual ed. 43:26-32. 

NOAA. 1985, Climatological Data, Annual Summary, South Carolina. Vol. 85, No. 13. 

Pielou, E. C. 1977. Mathematical Ecology. 

John Wiley & Sons. New York. 385 pp. 

Sheffield, R. M. 1979. Forest statistics for 

South Carolina, 1978. USDA Forest Service Res. 

Bull. SE-50. 

Van Lear, D. H. 1982. Some considerations concerning natural regeneration of southern pines. 

pp. 31-40 & Proc. 2nd Annual Forestry Forum, 

Dept. of Forestry, Clemson Univ., Clemson, SC. 

Van Lear, D. H., J. E. Douglass, S. K. Cox, 

M. K. Augspurger, and S. K. Nodine. 1983. 

Regeneration of loblolly pine plantations in 

the piedmont by clearcutting with seed in 

place. pp. 87-93 E. P. Jones (ed.) Proc. 

2nd Biennial Southern Silvicultural Research 

Conference. USDA Forest Service, Gen. Tech. 

Rep. SE-24. 

Williston, H. L. 1978. Uneven-aged management 

in the loblolly-shortleaf pine type. S. Jour. 

Appl. For. 2(1):78-82. 
FIYAWCIAL ANALYSTS OF ARTIFICIAL PINE REGENERATI I4 ii,%SB 

NATURAL REGEMEXATTOM USZNG IHPROVmEHT CUTS P 

Stephen R. Nodine and Arthur T, Shearin 2 

ABSTRACT.--In 1953 a 2-acre portion of a shortleaf pine-mixed hardwood 

stand was clear cut. The following year loblolly pine was planted and 

residual hardwoods were killed. The remaining acres of the original 

stand received an improvement cut in 1953, with no artificial regeneration. Part of that area was also eventually converted to pine by 1961. 

None of the three resulting stands received any treatment following 

that time. After 31 years of growth the loblolly pine stand produced 

12.5 MBF of sawtimber and 30 cords of pulpwood per acre, while the 

adjacent pine-hardwood stand produced 9.7 f.fBF of sawtirnber and 4,4 

cords of pulpwood per acre. After-tax annual equivalent values (AEV) 

for the pine and mixed pine-hardwood stands were $16.21 and $6,19, 

respectively. Even higher returns of up to $24.20 were projected under 

more intensive management schedules. The area which was eventually 

also converted to pines was projected to earn an AEV of $22.49. 

INTRODUCTION 

Nonindustrial private forest (NIPF) landowners 

currently control 74% of the 204 million acres of 

comercial forest land in the South. They have 

historically tended to be reluctant to invest 

heavily in their forest land. As a result, one 

approach that many take with regard to mixed stands 

is to thin them with what they may call '"improvement cuts," taking some of the trees and leaving 

the rest to provide for regeneration and continued 

growth. The attitude of "my Daddy and my Daddyv s 

daddy cut over this stand many times and neither 

one of them ever replanted any trees" prevents many 

owners from being willing to invest their money in 

reforestation activities. Unfortunately, this 

approach often amounts to little more than 

high-grading the stand. 

Euch has been written on the management of pine 

stands and the economic returns that are possible 

from such investments. Much less has been written, 

however, about the returns to be expected from 

managing mixed pine-hardwood stands, especially 

when they are under the extensive type of management that is common among many NIPF owners. Nany 

NIPF owners tend to resist the idea of converting a 

mixed species stand to a pine monoculture. This is 

partly due to the relatively high cost of such 

conversion, and partly to aesthetic concerns, By 

making the decision to continue thinning a mixed 

stand rather than converting it to a pine stand, 

omers may decrease the value of the stand and 

reduce the returns that they can earn from light to 

moderate investments in reforestation. 

'Paper presented at the 4th Biennial Southern 

SIlvfcultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

'~nstructor and Assistant Professor, respectively, Department of Forestry, College of Forest 

and Recreation Resources, Clemson University, 

Clemson, South Carolina. 

This paper investigates a ease history of a 

stand, part of which was converted from mixed pine 

and hardwoods to pines, and part of which was 

thinned in an "improvement cut." Actual stand 

growth is reported, as well as simulated growth 

under alternative management schedules, An 

economic analysis compares the profitability of 

each alternative and evaluates their relative 

merits, The results are not limited to NIPS 

applications, however, but have relevance to a11 

forest land. 

THE STUDY AREA 

The study area is a 37-acre stand located in the 

northern Piedmont region of South Carolina. The 

stand is a part of Clemson University's forest 

which is slanaged for educational and experimental 

purposes, as well as for its comercial value. 

The site has a loblolly pine site index of 105 at 

age 50. In 1953 thls area contained a mature 

(70-80 years old) upland stand composed of shortleaf pine and mixed hardwoods, As a demonstration 

of the emerging practice of chemical hardwood 

control, two acres of the stand were harvested 

with only commercial trees being removed. In 1954 

this area was planted with loblolly pine, and in 

1955 the residual hardwood stems were killed, 

Through these steps this stand was successfully 

converted from nixed pine and hardwoods to 

loblolly pine at a cost of approximately 209 of 

the value of the timber harvested, 

The remaining 35 acres of thls stand were also 

harvested in 1953 with what was intended to be an 

'Ymprovement cut." Nearly ail merchantable 

hardwood stems were cut along with a partial 

harvest of the shortleaf pine trees, At the time, 

there was no market in the area for hardwood 

pulpwood; but it was anticipated that the residual 

hardwood stems would continue with their growth 

into merchantable size classes, and that the 

remaining shortleaf pines would provide some 

natural regeneration as well as continued growth. 
As an indication of the success of this improvement cut, most of the stand was eventually 

converted to loblolly pine when it was recognized 

that the residual stand would not continue to grow 

at a profitable rate. A hardwood pulpwood market 

developed in the area in 1959, so the remaining 

merchantable hardwoods were cut and the rest 

girdled, and the shortleaf pines were cut to a seed 

tree stocking level. Loblolly pine was planted in 

a few areas which contained no seed trees. In 1960 

loblolly pine seeds were spread by hand to try to 

improve regeneration. By 1961 regeneration was 

still less than 200 pines per acre, leading to the 

planting of more pine seedlings. In 1964 competition from young hardwoods had become a problem for 

the pine regeneration, so the hardwoods were 

chemically controlled with 2,4,5-T. Two acres of 

this stand were not converted, however, to provide 

a basis for comparing the ultimate results of stand 

conversion versus improvement cutting. This left 

three distinct stands with different treatments for 

comparison. 

Since 1964 there have been no management 

activities on any of the stands. Periodic visits 

to the first converted stand recorded a very normal 

growth process. By age 12 the stand had a basal 

area of 40 sq itlacre, and by age 21 it had grown 

to 140 sq ft/acre. A note in the management record 

at that time recommended "Thin if research allows 

it." 

The two 31-year-old stands were measured in 1985 

to determine the results of these two regeneration 

methods. At that time, the following conditions 

existed in the two stands: 

Converted Natural 

Sawtimber (MRF/acre 

Int' 1 $" rule) 

Pine 12.5 3.8 

Hardwood 0.0 5.9 

Pulpwood (cordslacre) 

Pine 30.6 1 .O 

Hardwood 0.0 1.4 

Timber value ($/acre) $1,552 $582 

ECONOMIC ANALYSIS 

As indicated earlier, the intent of the comparison 

between these stand treatments was to evaluate the 

trade-offs between them. Conversion to a pine 

plantation gains faster tree growth, higher total 

volumes, and better stand composition. These 

benefits are only possible, however, when a 

significant amount of money is invested and held 

until trees become merchantable. A primary goal of 

natural stand management - in this case through an 

improvement cut - is to reduce the required 

investment while maintaining a viable stand. 

Comparisons can be made of the results of these two 

methods through a simple economic analysis which 

can account for all of the expenses incurred and 

incomes received, and the length of time between 

the initial investment and eventual incomes. 

In making an economic analysis one has to select 

an appropriate economic criterion upon which 

alternatives will be judged. The most common 

criteria which are used are Internal Rate of Return 

(IRR), Present Net Worth (PNW), and Annual Equivalent Value (AEV). Each criterion has its own set 

of assumptions, advantages, and disadvantages 

(Foster 1984), In this example, IRR cannot be 

used because the improvement cut example has no 

initial investment on which a rate of return can 

be computed, Since the initial analysis was 

extended to investment periods of different 

lengths Annual Equivalent Values must be used for 

the comparisons, 

Simply stated, AEV can be considered equivalent 

to the annual profit realized by an investment. 

Since forest stands do not normally return an 

annual income, one might think of this as an 

annuity which accumulates value each year but only 

pays out at a later date. Two assumptions are 

important to the use of AEV. First, the assumption 

must be made that timber management is perpetual - that is as one rotation is ended another begins. 

And second, a discount rate that is appropriate 

must be selected. This discount rate can be 

considered to be the cost of money to the woodland 

owner, or the next-best alternative rate of return 

that he could earn on his money. Though AEV is 

sensitive to the discount rate selected, and 

though it is often hard to get a consensus as to 

the appropriate rate to use, this analysis uses a 

representative landowner's discount rate, since 

the comparison being made is of the relative 

merits of two alternative management schemes, both 

of which face the same discount rate. 

Several items of information and assumptions 

necessary to the financial analysis are summarized 

in Table 1. Since these stands were managed 

during the time that a capital gains tax differential was in effect and a reforestation tax credit 

was not, it was assumed that the tax breaks in 

effect at that time would have been claimed, 

When a comparison of the values of the two 

31-year-old stands is made, an extreme difference 

in their profitability becomes apparent. The 

stand that received an improvement cut had an AEV 

of $6.19, while the converted plantation had a 

value of $16.21, nearly 2.5 times higher (Table 2). 

This might have been anticipated after seeing the 

volumes of timber that were present in each stand. 

Why did the natural stand compare so poorly? It 

appears that though the intent of the improvement 

cut was good and the logic sound, the actual 

implementation of the cut was faulty. The result 

of a well-executed improvement cut should be a 

stand of trees which can continue to increase in 

value at a reasonable rate, move into merchantable 

size classes, and/or provide for successful 

regeneration of the stand in the future (Smith 

1962). In this case, however, most trees that 

were left were overmature or poorly-formed; and 

there were few if any young trees which could grow 

into merchantable sizes. Subsequent natural 

regeneration in the stand has been minimal, leaving 

a stand of slow-growing, overmature or unmerchantable trees. Though the intent of the cutting was 

to improve the future prospects of the stand, the 

effect was not unlike that of highgrading. 
Table 1.--Assumptions Made and Data Used in the 

Financial Analysis. 

Federal income tax rate 

Before-tax discount rate 

Capital gains tax exclusion 

Stumpage prices (1985) 

Sawt imber 

Pine (Scribner rule) 

Hardwood (Doyle rule) 

Pulpwood 

Pine 

Hardwood 

30 percent 

6 percent 

60 percent 

$12/cord 

$41 cord 

Expenses for pine conversion 

Site preparation and planting (1954) $20/acre 

Hardwood control (1955) $lO/acre 

Expenses for delayed conversion to pine 

Hardwood control (1959) $3/acre 

Planting selected areas (1959) $7 /acre 

Direct seeding loblolly pine (1960) $20/acre 

Planting loblolly pine seedlings 

(1961) $2l/acre 

Hardwood control (1964) $9lacre 

Expenses for all stands 

Annual taxes and general management 

expenses $1 /acre 

Harvest expense 8 percent of 

harvest value 

Table 2. Comparison of Profitability for an 

"~m~rovement Cut," a Converted Stand, and a Delayed 

Conversion. 

After-tax Annual 

Stand Management Schedule Equivalent Value 

Improvement cut with one 

harvest at age 31 6.19 

Converted to pine with one 

harvest at age 31 16.21 

Simulated pine conversion with 

one harvest at age 31 14.98 

Simulated pine conversion with 

a thinning at age 21 and a 

clearcut at age 31 20.50 

Simulated pine conversion with 

thinnings at ages 20 and 30 

and a clearcut at age 35 24.20 

Delayed conversion with simulated 

thinnings at ages 20 and 30 and 

a clearcat at age 35 22.49 

Reflecting back on the management recomendation 

at age 21 that the converted pine stand be thinned 

if research permitted it, an investigation was 

made of the potential profitability of that stand 

if it had been managed more vigorously. To do 

that the cut-over site lobloify pine growth and 

yield simulator from the YIELD computer program 

(Hepp 1985) was used, The approximate stand 

condition at its establishment in 1954 had to be 

specified in order to simulate thinnings at 

earlier ages, Approximately 1,000 seedlings were 

planted per acre as was common practice at that 

time. Based on this growth and yield model, it 

was projected that the simulated converted stand 

would have an AEV of $14.98 if left unthinned, 

compared to the estimated value of $16.21 for the 

actual stand, Since the speculative management 

regimes were based on this same model, this 

simulated value was used for making comparisons. 

Next, several management schedules were 

simulated with intermediate thinnings and a final 

harvest by clearcut. It was found that all of the 

feasible management schedules were more profitable 

than a straight 31-year single harvest rotation. 

For example, if the stand had been thinned at 

age 21 and then clearcut at age 31 the AEV would 

have been $20.50. Carrying this further, 

thinnings at age 20 and 30 with a clearcut at 

age 35 yield an AEV of $24.20, representing an 

increase in profitability of nearly 50 percent. 

Any number of other thinning schedules with 

varying intensities could be tested to find the 

optimal management plan for such a stand, but the 

point can be made from these examples that active 

management with periodic thinnings can often be 

more profitable than single harvest rotations, 

depending on the assumptions that are made and the 

objectives of the landowner. 

Since 33 acres of the original stand were 

delayed in their conversion to pine, it was 

possible to evaluate the cost of the decision to 

try an improvement cut. The forest managers 

realized that the improvement cut had not left a 

desirable stand of timber, and they began to 

convert the stand in 1959. It took six years to 

complete the process, due to several factors 

including poor natural shortleaf pine regenertion, 

poor survival from direct seeding, and more 

intense competition from hardwoods. Total costs 

for completing this delayed conversion were $60 

per acre, compared to $30 per acre for tPe 

original conversion. Not only were costs higher; 

but since the stand was not fully stocked unti3 

1961, there is a seven year delay befcre the same 

timber can be harvested. Still, it turned nut to 

be better to eventually decide to convert this 

stand than to continue with the poorer mixed stand. 

The AEV of $22.49 for this stand under a simulated 

schedule of two thinnings and a final harvest 

compares well with our other examples, 
Many factors can influence the profitability of 

various management alternatives for mixed ti~ber 

stands. This example bas demonstrated that these 

atlernatives should be well-considered before they 

are implemented. A stand should be evaluated 

especially carefully before applying some type of 

'Ymprovement cut" to avoid the types of problems 

encountered here. Of paramount importance is the 

age of the trees, as this has great bearing on the 

ability of stands to continue growing at a 

profitable rate. Obviously it didn't take the 

forest managers long to realize that the mixed 

stand that was given this type of cut was not 

performing well. Unfortunately, by the time that 

stand was successfully converted to pine seven more 

years had elapsed, with a great deal more labor and 

expense involved and a longer wait for a commercial 

thinning to become possible. 

These implications are important to all forest 

managers, regardless of whether they work with 

mixed stands such as these or with single species 

even-aged stands. Decisions on thinning, 

harvesting, and regenerating a stand should be 

made with appropriate financial considerations, 

and with care taken to insure that the end result 

is that which was intended, It is especially 

important that these considerations be presented 

to private landowners who assume that if one stand 

of trees grew up on their land another stand will 

somehow also appear from the remnants of the 

first, 

LITERATURE CITED 

Foster, B. B. A service forester's guide to 

investment terminologies. Southern Journal of 

Applied Forestry 8:3(115-119); 1984. 

Hepp, T. E. User's manual for YIELD timber yield 

forecasting and planning tool version 1.4. 

Tennessee Valley Authority; 1985. 42 pp. 

Smith, D. M. The practice of silviculture. New 

York: John Wiley & Sons, Inc.; 1962. 578 pp. 
Ten Years After Midrotation Fertilization i 

Slash Pine Plantations: When Does It Pay?- 17 

Duane R. Dippon and Mohamad ~assanzl 

Abstract. In 1975 a series of midrotation fertilization 

test plots were established by the Coo~erative Research in 

Forest Fertilization Program at the University of Florida. 

Semimature slash pine plantations were fertilized with eight 

treatments in a 2 by 4 factorial with phosphorous and nitrogen 

broadcast on plots. Tree height and DBH were measured on each 

plot in the year of treatment with follow up measurements at 3, 

5, 8, and 10 years thereafter. A Weibuil diameter distribution 

model has been developed for predicting stand development as a 

function of the level of and time since the fertilization 

treatment. In general, both the rate of vol*me accumulation 

and the resulting total volume per acre are increased. 

Therefore, the present net worth of the stand as well as it's 

optimal financial rotation length are expanded by the 

treatment. Optimal fertilization treatments were found to vary 

by soil type and final product mix. 

INTRODUCTION 

Slash pine (Pinus elliottii Engelm. var 

Engelm) is one of the major softwood species grown 

in the southern United States. The species occupies 5.3 million acres in Florida (Bechtold and 

Sheffield, 19811, and a total of 12.8 million 

acres east of the Mississippi River (Sheffield et 

al., 1983). Slash pine ranks first in Florida and 

third in the Southern states in terms of growingstock volume, and is favored by many forest 

managers for its fast growth and excellent utility 

for pulp, lumber, poles, and gum naval stores 

(Sheffield et al., 1983). 

Demand for wood products from forests in the 

Southeast is projected to double by the year 2030 

(Haeussler, 1983). Because of strong competition 

for land by agriculture and urbanization for land, 

intensive forest management must be adopted in 

order to increase forest productivity and meet 

future demand without undue price dislocations. 

Fertilization is considered an important 

silvicultural tool for increasing site 

productivity and accelerating stand development 

(Duzan et al., 1982), The fertilization of forest 

stands was first started in the early 1960's in 

the southeast by industrial forestland owners, 

New plantations located on phosphorus deficient 

sites were the primary targets for eariy forest 

fertilization efforts (Bengtson, 1979), By 1972, 

fertilization programs had been extended to 

include established pine plantations for 'hidrotation" treatments. Since then, the total area 

undergoing treatment each year has been increasing 

steadily (~engtson, 1979). 

L/Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

The primary objective of this paper is to 

determine if and when midrotation fertilization 

applications are financially sound investments. 

The analysis focuses on the biological and financial responses of 11 test sites to eight 

treatment combinations of nitrogen and 

phosphorus. The data for this study was obtained 

from a series of fertilization trials (B200) carried out by the Cooperative research in Forest 

Fertilization (CRIFF) program at the University 

of Florida, Gainesville. 

APPROACH 

The CRIFF program is a group venture by 

forest industires in cooperation with the 

Department of Forestry and the Soil Science 

Department of the University of Florida. It was 

organized in 1967 to promote research in forest 

fertilization and to assist forest managers in 

making efficient use of forest soil resources for 

wood production purposes. The B200 series of 

fertilization trials were established by CRIFF on 

cutover forest land to quantify the volume 

response of established slash pine plantations to 

nitrogen and/or phosphorus applications. The 

B200 series consist of 11 tests in a 2 by 4 

factorial design with eight treatments in a 

randomized block design of three replications 

with all combinations of four levels of nitrogen 

and two levels of phosphorus. 

- 2IAssociate Professor and Graduate 

Research Assistant, respectively, 

Dept. of Forestry, Gainesville, PL 32611 
Nitrogen Phosphorus 

(iilb lac) 

0 0 

100 0 

200 0 

300 C 

400 0 

0 101) 

100 100 

200 100 

300 100 

400 100 

Gooding et al. (1978) divided the forest 

soils in the Southeast into seven groups on the 

bases of drainage class, depth and nature of their 

B horizon (Table 1). Fisher and Garbett (1980) declared that within these soil groups, chemical 

tests of soil or foliar nutrient concentrations 

may then be used to pinpoint deficient areas more 

precisely . 

SOIL GROUP DEFINITIONS 

SOIL MAJOR LAND IMPORTANT 

GROUP AREA DRAINAGE FEATURES 

A SAVANNAS VERY POOR SANDY SURFACE 

TO POOR LAYER LESS THAN 20 

INCHES DEEP, WITH 

CLAYEY SOIL BELOW 

SAVANNAS VERY POOR SANDY SURFACE 

TO POOR GREATER THAN 20 

INCHES DEEP, WITH 

CLAYEY SOIL BELOW 

FLATWOODS POOR SPODIC HORIZON BELOW 

THE SURFACE LAYER, 

CLAYEY SOIL BEL-OW 

THE HARDPAN 

PLATWOODS POOR TO SPODIC HORIZON 

MODERATE BELOW THE SURFACE 

LAYER, SANDY SOIL 

BELOW THE SPODIC 

UPLANDS MODERATE SANDY SURFACE 

TO WELL LAYER GREaTER THAN 

20 INCHES DEEP, WITH 

CLAYEY SOIL BELOW 

UPMNDS MODERATE SANDY SURFACE 

TO WELL LAYER GREATER TKAN 

20 INCHES DEEP, WITH 

CLAYEY SOIL BELOW 

SAND RILLS mCESSIVE SANDY SVRFACE 

MYER AT LUST 60 

INCHES DEEP 

 DRAINAGE RATINGS REFER TO THE REMOVAL OF WATER 

FROM A SOIL. THESE ARE INFLUENCED BY SOIL TEXTURE 

(SANDS VS. CLAYS) AND POSITION IN TWE MNDSCAPE 

(LEVEL VS. SLOPING LAND). (Table 1) 

The wide range in stand density, soil group 

and treatment ages for the B200 series are listed 

at the top of the next column. 

CRIFF TESTS 

COUNTY CRZFF AGE 

& STATE SOIL AT SQ. 

TEST LOCATION GROUP ESTAB, ACRE 

Ghatham, Ga B 

I-v'ajme, Ga B 

Wayne, Ga D 

tong, Ga B 

Nassau, F1 D 

Ealdwin, A1 E 

Calhoun, F1 B 

Nassau, Fl D 

Hamilton, 2'1 C 

Gulf, P1 A 

Madison, PL G 

To quantify the response of slash pine to 

the different fertilization levels, diameter and 

height of the trees were measured at the time of 

treatment and at three, five, eight and ten years 

thereafter. 

Based on the data from the £3200 series of 

mid-rotation fertilization trials, Lynch et al. 

(1985) developed growth models using the Wiebull 

diameter distribution technique. Their models 

estimate the total volume up through and including the eight years after the slash pine plantations were fertilized at mid-rotation. In this 

analysis, the same procedure was used but updated 

with the tenth year measurements. 

The financial analysis of the growth 

response, expressed in terms of the Internal Rate 

of Return (IRR) due to treatment, Net Present 

Worth (NPW) and Soil Expectation (Se) was 

performed using the following assumptions: 

Regeneration Cost = $146.00/ac 

Taxes and Administration = $5.00/ac/yr 

Nitrogen = $0.35/1b* 

Phosphorus = $0.70/lbfi 

Uninflated Discount Rate = 4% 

Stumpage Markec Value = $29.60/cd** 

f: Material plus application cost 

f:ft Merchantable volume inside bark, 2 in. top 

and Timber-Mart South, North Florida 

market prices. 

These assumptions are included in the analysis which is presented and discussed in the 

following results section. 

The scheduling of applications within the 

life cycle of the stand is an important aspect 

that must be evaluated. The scheduling contributes to the total cost of the investment along 

with the quantity of the volume response and, 

therefore, the stand's optimal rotation age. 

Pritchett and Comerford (1983) found that slash 

pine trees at age 12 to 20 years are more respcnsive to fertilization than younger trees. They 

suggested application of nitrogen no later than 5 

to 7 years before harvest in order to obtain the 

maximum benefit from the fertilizer. However, 

these conclusions are based solely from a 

biological standpoint, and may not be optimal 

from an economic viewpoint, 
RESULTS AND DISCUSSION 

Since the model originally developed by Lynch 

et al. (1985) predicts future survival, height and 

Weibull based diameter distribution based on treatment intensity and t,ime since the activity, 

it should be possible to estimate the optimal 

fertilization level and timing for the individual 

tests. By projecting the development of a stand 

after a midrotation fertilization treatment, 

volume responses can be quantified for future 

ages.. Although the availability of the diameter 

distribution of the stand allows detailed analysis 

of the financial implications of fertilization on 

multiple products production, this study will 

simplify the analysis and assume that pulpwood is 

the only merchantable product. 

Figures 1, 2 and 3 display the comparative 

height, diameter and volumes per acre, respectively, for tests from Soil Groups G, B, D and E (from 

left-to-right) . The subscript (c) represents the 

unfertilized control while the subscript (F) 

corresponds to the tests receiving 400 and 100 

pounds per acre of N and P, respectively. 

The tests demonstrate a great deal of 

variability to treatments in all respects. The 

average height growth (Figure 1) of the control 

plots in test B201 exceeded that of the full 

treatment plots. Conversely, the fully treated 

plots heights grew by almost 15 percent over that 

of the control by 10 years after the treatment for 

test B211. Whereas the average height growth 

differences were almost indistinguishable for the 

plots in test B201, the average tree diameter 

expanded by nearly 9 percent, the largest 

difference demonstrated for these four tests 

(Figure 2). After treatment survival ranged 

between 79 and 86 percent for the treated trees 

from the year of the study's initiation to ten 

years thereafter . 

Height Growth by Time Since Treatment I 

Figure 1. Average tree height by test and time 

since treatment (control vs. full) 

Diameter Growth by Time Since Treatment I 

Figure 2. Average tree DBH by test and time 

since treatment (control vs, full) 

After combining survival, height growth, and 

diameter distribution changes; Figure 3 displays 

the relative changes between the control and 

fully treated plots in terms of average volume 

per acre. Tests B201 and B211 increased their 

volumes by 16.7 and 20.7 percent, respectively, 

over that of the control plots after 10 years of 

growth following the fertilization treatment. 

The other tests increased their net per acre 

volumes by approximately 10 percent. 

Volume Growth by Time Since Treatment 

8Cswt n 1 

Figure 3. Average volume per acre by test and 

time since treatment (control vs. full) 

Figure 4 demonstrates the maximum volume 

responses for each of the tests for the range of 

treatments by ten years after the initial treatment. The most notable implications of these 

results is that while all of the tests appear to 

respond favorably to at least some level of 

nitrogen, the "best" treatment varies by test. 

In fact, only three tests do best with nitrogen 

alone (#4-400 lb,/ac.) whereas all of the others 

require 100 pounds of phosphorus along with some 

positive level of nitrogen. At this juncture, it 

is difficult to ascertain whether the optimal 

treatment level varies by CRIFF Soil Group. 
CRIFF 8200 SERIES 10th YEAR 

tif t ! ' 'I 

Figure 4. Maximum 10th year cumulative volume 

response by CRIFF B200 Test 

The "optimal" fertilization treatment should 

at least be based on whether the volume responses 

are sufficient to repay the costs incurred, and if 

so, how long the investments should be made before 

liquidating the stand. This is actually a joint 

optimization problem with the level of fertilization treatment, or intensity, serving as the 

initial cost of the investment while the number of 

growing seasons after the treatment represents the 

effect of the time value of money on the length of 

the investment. 

Figure 5 displays the diversity of the 

Internal Rate of Return (1RR)'s possible for a 

subset of the B200 series of tests for each 

treatment intensity. The figure demonstrates that 

the degree of response varies differently among 

tests for each of the levels of treatment intensity. 

Fert. Max. IRR by Test and Treatment " n 135 

- Fei-tilitat ion Treatment 

Figure 5. Maximum IRR to midrotation 

fertilization by test and treatment 

But these results only focus on the cost of 

the treatment versus the value of the treatment 

response over that of the control. While the 

figure does convey the most financially responsive 

treatments by test, the projected growth and 

development of the stand as an entity is ignored 

with the IRR procedure. If both the intensity of 

treatment and length of investment is to be optimized, then the changes in the Present Net Worth 

(PNW) of the stand can be examined for each test. 

Figure 6 displays the per acre PEjW of the stand 

over the entire range of fertilization treatments 

after ten years of growth. While the general 

trends in the value response due to the fertilization continue from Figure 5 to Figure 6, the 

latter figure demonstrates that large IRE values 

do not necessarily translate to significant 

changes in the stands overall PNW. In other 

words, whereas the individual treatment may 

generate a value response of 20 or 30 percent 

(~ests B202 and B211 with 100 ~b./ac. of P), the 

net value of the entire stand may be only changed 

by a few percent. 

Optimal PNW by Test and Treatment ,,, 

Fertilization Treatment 

Figure 6. Maximum per acre PNW by test and 

treatment 

The resulting change in total stand value 

(PNw) helps in defining the optimal fertilization 

level for the current stand in each test. However, Figure 7 demonstrates that the optimal 

fertilization intensity may vary if the Soil 

Expectation (Se) is the decision criteria used 

for the joint optimization problem instead of the 

PNW criterion. As Davis and Johnson (1987) 

explain, the optimal rotation decision should be 

based on Se rather than PNW since the latter 

ignores the cost of delaying future cash flows 

from the land as compared to evaluating the value 

of the current stand as an entity to itself. 

OPTIMAL TREATMENT BY DECISION CRITERIA e 1 

taa sot arr am 211 22s slo nr zm 227 150 

Figure 7. Optimal treatment by CRIFF B200 Test 
Although the decision criteria calculate different 

dollar values, the figure demonstrates that only 

three tests (~150, B224, and B230) change 

the optimal treatment intensity for the two 

decision criteria, In the three cases where a 

change occurs, the optimal treatment defined by 

the Se criterion, drops the nitrogen from the 

optimal PW treatment, 400 N and 100 P pounds per 

acre, for the three tests. The optimal treatment 

intensity for the other tests are unaffected by 

this change in decision criterion. 

While the intensity of treatment may not be 

very variable to the two decision criteria, Figure 

8 displays that the jointly determined rotation 

length is highly sensitive. In all cases, the Se 

optimal rotation length is less than or equal to 

that determined by the PNSJ criteria. Mhen keying 

on the Se value decision criterion, the 

combination of Figures 7 and 8 present the optimal 

treatment intensities and rotation lengths for 

each of the B200 series of tests. Referring back 

to Figure 4, the economically optimal fertilization treatments were not always determined by 

simply examining the biologically optimal 

treatments. In addition, the set of economically 

optimal treatments can be expected to be changed 

as the cost of materials, application, value of 

final products or the alternative rate of return 

assumptions are altered to fit the real world 

situation of the forest manager. 

$4 

1s 

trC 

tm IBI am gl zri me lia nt m nn ua 

Figure 8. Optimal Rotation by CRIFF B200 Test 

DISCUSSION 

Returning to the CRIFF Soil Groups, several 

points can be made. The phosphorus deficient A 

soils (B227) respond best to 100 poundslacre of 

phosphorus. However, the optimal rotation length 

is really unknown with an alternative rate of 

return of 4 percent (i=0.04) since the Se value 

continues to increase up through the fifteenth 

year of the projection. In reality, such soils 

would be probably be better served by a phosphorus 

treatment at the initiation of the stand rather 

than at some point during midrotation. 

The model does not appear to give very good 

projections when the age of the stand at initialization was less than ten years of age (B220 and 

B224). The initial feeling by the authors is that 

the plots are growing at such rapid rates at 

these younger ages and the time frame for 

measurements is so brief relative to the stand's 

development, th; . the projections of stand 

value consistently increase at a rate greater 

than four percent. 

For the most part, the B Soil Group tests 

(B150, B201, B209, and ~220) respond best to a 

treatment of 400 K and 100 P per acre with an 

investment period ranging between 6 and 9 years. 

The optimal rotation ages for these tests varies 

between 19 and 22 years of age. 

The only other CRIFF Soil Group which has 

more than one representative BZOO test is that of 

the D group with B202, B211 and B221, Cooperators have indicated that the last test has suffered unusual mortality levels due to fusiform 

rust and may therefore not present a good 

estimate of response to midrotation 

fertilization. Therefore, if the first two tests 

are considered alone, 100 pounds of phosphorus 

per acre alone over a 5 to 6 year investment 

period appears to be the optimal treatment for 

the D Soil Group. 

The only test for the E soil Group (B219) 

indicates that midrotation fertilization of any 

intensity or duration is unprofitable. The 

control is the optimal treatment with a harvest 

of the stand by age 20. Conversely, the test 

from the Soil Group G (B230) indicates that 400 

pounds of nitrogen per acre can be successfully 

invested for 10 years with a resulting optimal 

rotation age of 23 years of age and a real rate 

of return of 4 percent. 

SUMMARY 

The authors realize that the B200 Series 

of midrotation fertilization treatments represent 

a very small data set on which to base broad management prescriptions. What is presented is a 

discussion of the proper methodology for the 

determination of the joint optimization problem, 

intensity and investment period. Based on the 

estimated production relationships and financial 

assumptions, the calculations indicate that given 

the economic assumptions made, midrotation 

fertilization appears profitable for all but one 

of the tests. In addition, except for the tests 

which were less than ten years of age at 

treatment (B220 and B224) and the one test from 

Soil Group A (B227), the optimal rotation ages 

for these slash pine sites ranged between 19 and 

23 years of age. While the site index values for 

the sites are unknown, these rotation ages are 

comparable for optimally defined (Se) rotation 

lengths for untreated stands based on other slash 

pine growth and yield models. 

Although the analysis approached the 

problem as a two variable joint optimization 

problem, in reality it is much more complex. The 

real question is not just how much fertilizer and 

then when to harvest the stand, we really also 

need to know at what age should the treatment be 

initiated? In addition, we could also include 

the option of the optimal timing and intensity of 

thinning operations in the stand. The original 

study did not provide the level of data necessary 

to answer the former question. Fortunately, it 

has been an operational rule of thumb that slash 

pine stands do not react well to silvicultural 

treatments once crown closure has occurred. 
treatments once crown closure has occurred. 

Therefore, given the surviving density of the 

stand, a forester in the field may be able to 

determine whether fertilization nay be attempted. 

Once the decision has been made, the methodology 

presented can be used as a guide in determining 

the optimal treatment and length of investment for 

the stand. 

LITERATURE CITED 

Bengtson, George W. 1979 Forest fertilization in 

the United States: Progress and report. 

Journal of Forestry 78(3):222-229. 

Bechtold, W.A. and R.M. Scheffield. 1981. Forest 

Statistics for Florida, 1980. USDA Forest 

Service Resource Bulletin. SE-58 40 p. 

Davis, L.S. and K.N. Johnson. 1987. Forest 

Management. 3rd edition. McGraw-Hill 

Book Co. New York. 790 p. 

Duzan Howard W., H. Lee Allen, and R. Ballard. 

1982. Predicting fertilizer response in 

established loblolly pine plantations with 

basal area and site index. Southern Journal of 

Applied Forestry 6(1):15-19. 

Fisher, R.E. and W.S.Garbet. 1980. Response of 

Semimature slash and loblolly pine plantations 

to fertilization with nitrogen and phosphorus. 

Soil Science Society American Journal 

44:850-854. 

Gooding J.W., R.F.Fisher, W.S. Garbett, and 

V.W. Carlisle. 1978. Florida soil identification 

Handbook. Florida Cooperative Extension 

Service. Institute of Food and Agricultural 

Sciences. University of Florida. 12pp. 

Haeussler, Fred W. 1983, The managed slash 

pine ecosystem. Proceeding of a symposium 

held at the University of Florida. School of 

Forest Resources and Conservation. University 

of Florida, 1983:l-3. 

Lynch, R.O., A.V. Mollitor, and N.B. 

Comerford. 1985. Modeling effects of 

mid-rotation fertilization on slash pine 

plantation diameter distributions. Proceeding of 

a symposium held in Atlanta, Georgia. USDA 

Forest Service General Technical Report. 

SO-54:445-450. 

Pritchett, W.L. and N.B. Comerford, 1983. 

The managed slash pine ecosystem. Proceedings 

of a symposium held at the University of Florida 

School of Forest Resources and Conservation. 

University of Florida. Gainesville. 69-90p. 

Sheffield, R.M., H.A. Knight, and J.P. McClure. 

1983. The slash pine resource. Proceedings of 

a symposium held at the University of Florida. 

School of Forest Resources and Conservation. 

1983:4-23. 
TCITENTY-YEilR SLASH PINE SPACING STUDY : 

ISEIATO OPTIMIZE?I/ 

Doug owli in&/ 

Abstract:--Measurements at 5, 10, 15, and 20 years are 

summarized for a slash pine spacing study in Decatur County, 

Georgia. Four densities (400, 600, 800, and 1000 treeslacre 

(TPA) planted) were overlaid by a thinning treatment at age 

15 on half of the plots, Twenty-year yield is financially 

analyzed four ways: (1) pulpwood only, (2) merchandising 

chip & saw, (3) pulpwood adjusted for logging cost, and (4) 

merchandising with a logging cost variable. Optimum spacing 

varies with analysis, but unthinned 400 TPA appears superior 

at age 20, 

INTRODUCTION 

One of the first and most important management decisions in a pine rotation is the initial 

planting density. This decision is commonly a 

controversial issue, since it involves seeking a 

financial optimum. Determining that optimum 

requires forecasting at least 20 years into the 

future. Market values and specifications (size 

and wood quality) for those products must be 

established. 

Perhaps most speculative of all, the performance of forest products must be compared to 

the general economy. This forecast indexes 

relative appreciation or depreciation of those 

products, With all this guessing, a single 

answer to the optimum spacing will not go 

unchallenged. 

This paper presents and discusses a slash pine 

spacing study that has been measured over the 

last 20 years. Various approaches to 

determining the optimum spacing will he considered. 

METHODS 

In the spring of 1964, a replicated slash pine 

spacing study was planted at International Paper 

Company's Southlands Experiment Forest in 

Decatur County, Georgia. The site selected was 

an old-field on an Orangeburg soil. Six 

Lf~a~er presented at Southern Si lvicultural 

Research Conference, Atlanta, GAY November 4-6, 

1986. 

./stand Management Research Forester, 

Internationz' Paper Company, Bainbridge, GA 

31717. 

replications of this study are presented in this 

paper. Four spacing treatments are installed 

within each replication: 400, 600, 800, and 1000 

TPA. To ensure accurate spacing, extra 

seedlings were planted adjacent to the study. 

After the first growing season, any seedlings 

that died were replaced using a Council 

transplanter to maintain soil around the roots. 

Following the 15-year measurement half of the 

plots, three reps, were selectively thinned to a 

basal area (BA) of 80 ft2/acre across all 

spacings. A row was removed for access in the 

800 and 1000 TPA treatments. 

Measurement plots ranged from 35 to 65 trees 

depending on the spacing used. These plots were 

measured at age 5, 10, 15, and 20 years. 

Diameter at breast height (DBH), height, and 

disease condition were collected for each tree 

on the plot. 

Summaries derived from these measurements are 

total RI; and merchantable volume (WOL) of the 

5-inch class and larger to a 4-inch top. The 

volume equatfon used at all times was derived by 

Schmitt and Bower (1970) for slash pine total 

inside bark volumes. MVOL was calculated using 

Kax and Burkhart (1976) volume ratio approach. 

Conversion to cords used a factor of 75 ft3 

inside bark/cord . 

Pulr,wood $imensions include the 5-7 inch DBli 

classes to n 4-inch top. Chip & saw dimensions 

Sncludc the 8-11 inch DBH classes to a 6-inch 

top. Fiftef.1 percent of the chip & saw size 

material was devalued to pulpwood because of 

disepsc or defect, At t5e last measurement very 

few stems exceeded the 11-inch class. Those few 

stems were jneluded with the chip L sat7 class, 

Timber values r-aerr taken from the Southwide 

Surrrnary of Timber EIart-South July issue (1986), 

Pulnuood ntunn~lge was listed at $12/cord, and 

chi3 & saw sttiqnace was listed at $3l/cord, 
GROWTH AND RESPONSE 

The stand development at ages 5, 10, and 15 

years are presented as an average of six 

replications in Tables 1, 2, and 3, respectively. 

Stand conditions imediately following the 

thinning at age 15 are presented in Table 4 for 

the thinned plots. Table 5 presents the stand 

summary at age 20 for both the unthinned and 

thinned treatments. Each is an average of three 

replications. 

Table 1.--Stand conditions at age 5 by initfal 

spacing treatment. 

- - 

Variable 400 600 800 1000 

DBH (in.) 2.3 2.3 2.2 2.1 

Height (ft) 12 12 12 12 

BA (ft2/ac) 12 17 2 2 2 4 

TPA 3 91 576 758 951 

By age 5 the stand had not yet begun intraspecific competition. The DBH and height 

measurements showed no important differences. 

The BA was nearly a direct function of the 

number of surviving TPA. 

Table 2.--Stand conditions at age 10 by initial 

spacing treatment. 

Variable 400 600 800 1000 

DBH (in.) 6.1 5.5 5.2 4.8 

Height (ft) 34 33 3 2 31 

BA (ft2/ac) 7 7 9 5 112 122 

TP A 377 564 737 943 

MVOL (cdfac) 10 10 9 8 

differentiation in DBN across spacings, The 

largest DM'S sere found at 403 TPA, while the 

greatest BA was found at PO00 TPA, At age 10, 

however, the merchantable volume was less for 

800 and 1000 TPA than for the Lower densities. 

Nearly half the stems at the higher densities 

had not yet crossed the perchantable limit into 

the 5-inch class, 

Table 3,--Stand conditions at age 15 prior to 

thinning by initial spacing treatment, 

Variable 

DBH (In,) 7.6 6.7 6.2 5.8 

Height (fe) 5 3 5 1 51 5 0 

BA (ft2/ac) 135 136 150 154 

TPA 350 540 691 808 

WOL (cd/ac) 2 7 2 8 28 2 6 

By age 15 the effect of initial density on 

individual stem DEB was even more pronounced. 

The average DBR of the 400 TPA spacing was 

nearly 2 inches greater than the 1000 TPA. 

Essentially there was no difference among 

merchantable volumes acrcss all spacings. The 

previously non-merchantable stems of the higher 

densities had grown into the 5 inch class. 

Thinning revoval in the 400 TPA treatment was 

20-30 percent less than the higher densities, 

but the cut dianeter was 1.0-1.5 inches larger, 

The compensating effect of these two facts 

definitely impact the logging cost, An analysis 

should focus on whether the additional 2-4 

eords/acre in the higher densities covered the 

additional cost of harvesting smaller DBH stems. 

The residual stand in the 400 TPA treatment 

showed both the greatest average DBH and the 

greatest merchantable volume/acre. The analysis 

will need to focus on growth after thinning and 

estimated stand values at age 20. 

By age 10 competition between the surviving 

pine stems had already caused a strong 

Table 4.--Residual stand condition and thinning removal description at age 15 by initial spacing 

treatment. 

Residual Stand Thinning Removal 

Variable 400 600 800 1000 400 6 00 800 1000 

DEE (in,) 7.8 7.3 6.6 Sel 7.1 6,L 6,0 5.6 

Height (ft) 5 3 5 2 5 1 50 5 3 5 2 5 1 50 

2 BA (ft /ac) 8 0 7 9 7 9 7 7 3 5 5 7 7 1 7 7 

TP A 234 262 324 364 12 6 278 367 444 

MVOL (cdfac) 19 18 16 14 8 L 0 12 12 
Table 5.--Stand conditions at age 20 for the unthinned and thinned treatments by initial spacing. 

Unt hinned Thinned 

Variable 4 00 600 800 1000 400 000 800 1000 

13BH (inches) 8.4 7.3 6.9 6.4 8.9 8.5 7.6 7 ,O 

Height (feet) 6 3 62 6 1 58 6 5 64 6 1 5 9 

2 BA (ft /acre) 144 156 174 166 103 9 8 105 102 

Treeslacre 356 5 16 642 713 230 244 318 359 

PlrJOL (cdlacre) 42 42 4 5 3 8 3 2 2 9 2 9 2 6 

By age 20, whether thinned or not, the 400 TPA 

spacing produced DBHts nearly 2 inches larger 

than the 1000 TPA and 1 inch larger than the 

unthinned 600 TPA spacing, Maximum unthinned BA 

occured in the unthinned 800 TPA spacing, 

Earlier the peak BA had beenat 1000 TPA. Due 

to 12 percent mortality, the net BA growth of 

the 1000 TPA treatment had greatly slowed, e.g., 

12 ft2/acre in the last 5 years. 

Over the last 5 years, mortality in the 400, 

600, and 800 spacings was 1, 4, and 7 percent, 

respectively, As the rotation length increases, 

it is probable that the SO0 (and perhaps finally 

the 400) TPA spacing will produce the peak BA. 

Greater MVOL growth occurred on the unthinned 

treatments ranging from 2,4 to 3.4 cords/acre/ 

year. The thinned treatments produced from 2.2 

to 2.6 cords/acre/year, 

WHAT TO OPTIMIZE? 

Pulawood Onlv 

Now back to the question of which initial 

planting density and management strategy yields 

the best return. One approach might be to 

optimize merchantable volume production. The 

same result is achieved when all the volume is 

sold at a flat stumpage as pulpwood. This 

approach simply multiplies the MVOL by a 

constant value per cord. The result is in Table 

6, where Timber Mart-South stumpage values of 

$12/cord were used. 

Using a single value for stumpage across all 

of the stand conditions only acknowledges MVOL 

in cords per acre as the measure of stand 

value. This results in an equal ranking of the 

400, 600, and 800 TPA spacings. The 800 spacing 

is slightly ahead, but not by a signifirant 

margin, The 1000 TPA spacing falls behind by 

$50-90/acre, This approach, however, ignores 

the reality of economic constraints and 

opportunities. Even if wood production were the 

only organizational goal, low cost production 

should be considered. 

Table 6.--Average stand value at age 20 as 

pulpwood only. 

Variable 4 00 600 800 1000 

Unt hinned 5 04 504 540 456 

L/Thinning removal valued as $12/cord and 

appreciated by 5 years at 5 percent. 

Merchandising Chip & Saw 

More factors than MVOL establish the selling 

price of a stumpage sale, The winning bid will 

most likely be based on separating out higher 

valued products such as chip & saw, peeler 

bolts, and sawlogs. This is well illustrated in 

a recent article by Greber and Smith (1986). 

This 20-year-old slash pine stand already offers 

opportunities for merchandising at least 5 

cords/acre of chip d saw logs from the 8-11 inch 

DBH classes. Fifteen percent of these larger 

DBH stems were devalued to pulpwood because of 

disease and stem defect, Table 7 shows the 

comparisons sorting chip & saw valued at 

$3l/cord. 

Table 7,--Average stand value at age 20 sorted as 

chip 6 saw and pull.~~ood, 

Variable 4 00 600 800 1000 

Unt hinned 968 792 793 606 

L1lhinning removal valued as $12/cord and 

appreciated by 5 years st 5 percent, 
The inpact of sorting out higher valued 

products is striking, In the unthinned 

spacings, the value per acre increased by 30-90 

percent over the pulpwood-only analysis, Since 

the 4Q0 TPRs spaciqg had the largest DM, it 

added the most value, $459/acre (through 

rcrchandising the larger diameter products), 

This places tbe unthinned LOO TPA treatment well 

ahead of the other alternatives. 

The thinning treatment was applied to 

stimulate diameter growth and create higher 

valued products, The thinning treatment 

sufficiently increased chip & saw volumes in the 

600 and 106C TPA spacings to result in values 

above their unthinned counterparts. 

The 400 TFA snaeing already produced a large 

amount of chip & saw without thinning. The 

value increase will therefore need to occur in 

the sawlog class. By age 20, only 5 years after 

the thinning, none of the spacings had enough 

sawlog volume to merchandise. In future pears, 

perhaps as soon as age 25, the thinned 400 TPA 

spacing may begin to produce sawlogs and show a 

financial advantage to thinning. 

Adjusting for Logping Cost 

In addition to XrOL and product separation, 

expectcd loggi~p cost significantly affects the 

stumpage value of the stand, Spacing dependent 

parameters such as cut BBH and cut volume affect 

the logging cost, To some degree this is 

accounted for in the price spread between 

pulpwood and chip & saw, Even within the 

pulpwood or chip & saw classes, however, there 

exists erringh range in DBN to adjust the 

stumpage value for variable logging cost. 

Ti~e AII~G~T) Harvesting Analyzer (1986) was used 

to rc+ablish the esti~ated logging cost for the 

p~ltpr*~ od and chip & saw within each treatment, 

7" r r,t.~ri;pape values were then ad j11sted for 

Lci;.-ing cost (Figure I), The pulpwood value of 

Fiplrre i , LOGGING t"-"lr%PJUSTED STMPAGE 

a- CHIP % SAW 

$12/cord was assumed to be based on an average 

DBH of 7 inches, The chip & saw value of 

$3l/cord was assumed to be based on an average 

DBN of 10 inches. If the chip & saw occurring 

within a treatment averaged less than 10 inches, 

the difference in logging cost between that DBH 

and the 10 inch average was subtracted from the 

stumpage value. If the treatment BEH was 

greater than the 10 inch average, the difference 

was added to the stumpage, Table 8 shows the 

result of adjusting pulpwood and chip & saw 

stumpage for logging cost. 

Table 8.--Average stand value at age 20 sorted as 

chip & saw and pulpwood and adjusted for logging 

cost. 

Variable 400 600 800 1000 

---------- $lac re------------ 

Unthinned 824 583 499 205 

Ll~hinning removal valued as $12/cord and 

appreciated by 5 years at S percent. 

Across all spacings and thinning treatments 

the values fell from the previous estimates when 

chip & saw was merchandised without considering 

logging cost. This results primarily from the 

average cut DBH being less than the 10 inch 

average for chip & saw, The stumpage fell 

accordingly from $3l/cord. The reduction in 

stand value is greater as the initial spacing 

increased from 400 to 1000 TPA, i.e., from about 

$100/acre to more than $400/acre. The unthinned 

400 TPA treatment still generates the greatest 

value. 

The logging cost adjustment may also be 

applied when pulpwood is the only product. In 

this case the average cut DEN may be above or 

below the 7 inch index diameter. The unthinned 

400 and 600 TPA received a premium above the 

$12/cord average stumpage. The unthinned 800 

and 1000 TPA were both devalued for the small 

average diameters. This changes the ranking of 

TPA from flat, as in Table 6, to a strong trend 

(Table 9). The 400 TPA planting is more 

valuable whether thinned or not because it is 

cheaper to harvest. 

Further Steps of Analysis 

As additional data is gathered on this study, 

the impact of merchandising sawlogs will add a 

new dimension to product separation. Other 

steps are available to further refine the 

process of estimating the value of future stands 

of timber. 
Table 9,--Average stand value at age 20 for 

pulpwood only adjusted for logging cost, 

-- -- 

Variable 400 600 800 1000 

---------- $lacre------------ 

Unthinned 7 14 554 4 99 254 

~hinne&/ 721 554 469 247 

Li~hinnin~ removal valued as $12/cord and 

appreciated by 5 years at 5 percent. 

Sawlog grade is affected by natural pruning. 

Natural pruning is likewise altered by initial 

planting density, Therefore, high density 

spacings that would prune earlier may be more 

valuable through higher sawlog grade. The issue 

of natural pruning at lower initial planting 

densities is even more critical for loblolly 

pine where live crown and dead branches persist 

lower on the bole than for slash pine. 

These additional refinements may affect the 

current superiority of the unthinned 400 TPA, 

With age the thinning treatment should gain an 

advantage, Once sawlog grade is a factor, the 

thinned 600 TPA may become very competitive for 

the top position, The spacing debate will 

continue, however, because the market value of 

sawlogs will fluctuate and different organizations will use different appreciation rates for 

future value calculations. Hopefully some of 

these ideas will add to the accuracy in ranking 

silvicultural options, 

LITERATURE CITED 

Burrows, J. O., W. D. Greene, R. L. Lanford, and 

R, A. Tufts. 

1986. Auburn Harvesting Analyzer. School of 

Forestry, Auburn University. 

Greber, B, J. and H. D. Smith. 

1986. An analysis of multiple product nerchandising strategies for loblolly pine stumpage. 

South. J. Appl. For. 10(3):137-141. 

Max, F. A, and H. E, Burkhart. 

1976. Segmented polynomial regression applied 

to taper equations. For. Sci. 22:283-289. 

Norris, F. W. 

1986. Timber Mart-South (July). 

Schmitt, D, and D, Bower. 

1970. Volume tables for young loblolly, slash, 

and longleaf pines in plantations in south 

Mississippi. USDA For. Serv. Res. Note 

SO-102. 
Federal Income Tax Treatment of Silvicultural 

and Eelated Costs Associated With Intermediate Stand Management 

I 

William C. Siege1 2 

Abstract.--Many silvicultural and related practices are 

associated with the intermediate autnagement of southern forests. 

To partially recover the costs of such activities on a federal 

income tax return, the expenditures must be either capitalized or 

deducted as operating costs. The correct and optimal procedure, 

whether mandatory or optional, depends on a number of factors. 

The current (1986) law governing this area of the fedekal income 

tax law is discussed, followed by an analysis of how procedures 

will change in 1987 under provisions of the 1986 Tax Reform Act. 

Keywords: Expensing, capitalization, business, investment, 

stand maintenance, stand establishment 

Msny silvicultural and related practices are 

utilized by foresters in the management of 

southern forests. Such practices are employed 

during both stand establishment and intermediate 

Planagement. Some, depending on the silvicultural 

system, are also used during the pxe-harvest 

stage. The Internal Revenue Code permits recovery 

of part of the costs of these activities if 

reported on the landowner's federal income tax 

return. To recover silvicultural and related 

expenses, they must be either capitalized or 

deducted as operating expenditures. The latter 

procedure is often called "expensing." 

The extent of savings depends on which of these 

methods is used and the timing of the practice. 

The correct or optimal tax procedure, whether mandatory or optional, in turn depends on: (1) what 

the practice is, (2) its purpose, and (3) the 

taxpayer's tax status and cash-flow position. 

Being able to treat a particular silvicultural 

expenditure in a certain way for federal income 

tax purposes, as opposed to another way, may mean 

the difference between the activity being costeffective or not. Recent tax law changes have 

further added to the confusion. 

The distinctions between capitalization and 

expensing, and between stand establishment and 

intermediate management, are reviewed herein. 

The present (1986) law concerning the federal 

income tax treatment of silvicultural and related 

costs associated with intermediate stand management is also discussed. Finally, the changes 

indicated by the 1986 Tax Reform Act are 

addressed. Guidelines are presented to assist 

managers and landowners in making the proper 

federal income tax determinations. 

'paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

'chief Economist and Project Leader, Southern 

Forest Experiment Station, Forest Service, U.S. 

Department of Agriculture, New Orleans, LA. 

COST RECOVERY PROCEDURES 

Capitalization and expensing are authorized in 

general terms by the Internal Revenue Code. The 

statute makes no specific mention of timber, nor of any other particular enterprise or asset. 

Capitalization 

Section 263 of the Internal Revenue Code 

provides that amounts expended for real estate 

and equipment used for business or investment purposes or for making improvements that increase 

the value of such property -- including forest 

land and standfng timber -- are nondeductible 

capital costs. The test to be met is that the 

benefits of capital expenditures must be either 

permanent or those that will last for a determinable period of more than 1 year. Such costs 

must be capitalized -- that is, they must be 

segregated into a capital account. They are 

generally not recoverable immediately, but 

rather are deducted from income over a period of 

time as the capital asset or improvement with 

which they are associated is gold, used up, or worn out. The precise procedures employed to 

recover capital costs vary, depending on the 

nature and useful life of the asset acquired or 

the practice undertaken. Capitalized silvicultural and related expenditures are treated in 

one of two ways -- deducted from sale proceeds or amortized. 

Deduction from Sale Proceeds 

Deduction of a capitalized expenditure from sale 

proceeds is usually the least desirable recovery 

method from the taxpayer's standpoint. However, 

this procedure must be followed for items with a permanent or indeterminable life or for practices 

3The term **nondeductible" as used here does not mean that such costs are not deductible per se, 

but rather that they cannot be taken as a current 

deduction in their entirety in the year they are 

incurred. 
with a permanent benefit. Not only is the deduction deferred until the asset is sold (sometimes a 

period of many years), but before 1987 it usually 

offset a long-term capital gain that was taxed at 

a much lower rate than was ordinary income. 

Capital expenditures not associated with 

machinery or equipment or not otherwise depreciable, but which add value to a capital asset by 

providing a determinable nonpemanent benefit of 

more than a year"s duration, may be amortized. 

That is, they may be deducted in annual installments over the life of the benefit or, in some 

instances, over another specified period of time. 

These deductions may be offset against ordinary 

income from any source. 

Expensing 

As authorized by Sections 162 and 212 of the 

Internal Revenue Code, expenditures categorized as 

operating costs may be deducted in full from ordinary income from any source (expensed) in the year 

they are incurred. These expenses -- sometimes 

referred to as "ordinary and necessary" costs -- are those generally related to the income potential of the property (Briggs and Condrell, 1980; 

U.S. Department of Agriculture 1982). Expensing 

is more advantageous than capitalization because 

the entire deduction is taken in the year that the 

cost is incurred and may always be offset against 

ordinary income from any source. The return of 

capital is immediate -- a dollar saved today is 

more valuable than one saved later. 

CAPITALIZATION VERSUS EXPENSING OF SILVICULTURAL 

AND RELATED COSTS 

How should the costs of specific silvicultural 

and related practices be treated on the federal 

income tax return? All those+eosts directly associated with stand establisfinrent $re capital expenditures and must be capftalfzed. Included are 

costs incurred for the purchase of standing trees, 

site preparation, direct seeding, planting, and 

any practices necessary to ensure seedling survival and establishment -- that is, a free-to-grow 

status. 

On the other hand, most sikvicultural and 

related expenses incurred for maintenance and 

improvement of an established stand (intermediate 

stand management) or for stand protection, are 

usually considered to be current operatfng costs 

-- that is, ordinary and necessary expenditures -- and thus expensable. There are, however, some 

exceptions to this general rule. For example, 

even though particular machinery or equipment 

costs may be incurred in association with intermediate stand aianagement, they are nevertheless 

considered capital items and must be capitalized. 

All property taxes and interest, whether associated with stand establishment or intermediate 

4~reasury Regulation 1.611-3(a) . 

management, are expensable. A11 costs eligible 

for expensing may -- at the taxpayer's option -- be capitalized as "carrying charges" instead of 

being expensed and thus $educte$ from sale Income 

when the timber is cut or sold* 

Recovery of Star3 Establishment Costs 

Before 1980, capitalized stand establishment 

costs could only be recovered as a deduction from 

sale proceeds when the timber was cut or sold. 

This type of recovery is not nearly as advantageous as a more timely deduction from ordinary 

income from any source. 

Since 1980, however, the first $10,000 of annual 

stand establishent costs, even though capitalized, have been recoverable by amortization before 

the trees are cut or sold. A fiction in the law 

was created, setting the useful life of the trees 

at 7 years. The qualifying expenditure is amortized over 8 tax years, beginning with the year 

the cost was incurred. One-fourteenth of the 

expense is deducted that year, one-seventh during 

during each of the next 6 years, and the remaining 

one-fourteenth in the elghth year. These deductions may be taken whether or not ehe taxpayer 

itemizes deductions on his or her tax return. In 

addition, a 10-percent tax credit 1s also allowed 

(10 percent of a maximum sf $10,000 per year). No 

changes were made in the amort9zatisn or credit 

provisions by the 1986 Tax Reform Act. 

The amortization and credit provisions are separate tax return elections. Either or both can be 

selected or rejected. If the taxpayer, for some 

reason, chooses not to amortize qualifying expenditures, they may be recovered by capitalizing in 

the traditional way -- as an offset when the tintber is cut or sold. Hn any event, a11 establishment costs in excess of $bO,OQO per year must also 

be recovered by that method. 

Stand Establishment Versus Stand Maintenance 

When does stand establishment end and intermediate management (stand maintenance) begin for 

federal income tax purposes? Some silvicultural 

situations obviously fall into the establishent 

category and some into the intermediate management category. With others, however, the Law is 

less clear, and it is sometimes a major problem 

to deternine whether a sflvicultural activity is 

legally part of the stand esbabBfshnient process 

or, alternatively, is asseeiated with maintaining 

and improving an established stand. There are no 

"hard and fast" rules. IE many respects, this is 

a gray area of the tax law* Often the distinction 

is not clear and depends on s number of factors, 

all of which must be considered. 

Sometimes a single practice nay fall into both 

categories at the same time and thcs serve a dual 

purpose. An allocation may then be made between 

expensing and capitarization, with the cost 

'~nternal Revenue Code Sections 265-266; 

Treasury Regulation 1.266-1. 
proportionately divided. Removal of cull or 

low-value trees in a mixed-age stand containing 

both older trees and young seedlings is an example 

of such a situation, The tree removal could perhaps be necessary for seedling survival while 

enhancing the growth of the established trees. 

Prescribed burning in such a stand could also 

serve the dual purpose of site preparation and 

fire protection. 

A detailed discussion of this particular area 

of the tax law is beyond the scope of this paper. 

For an in-depth treatment, see Siegel (1984). 

EXPENSING INTERMEDIATE MANAGEmNT COSTS 

With this background, the details of expensing 

those silvicultural and related costs clearly 

associated with intermediate stand management are 

examined. Such expenditures include, but are not 

limited to, those incurred for various tjmber 

stand improvement practices such as hardwood or 

cull tree deadening, brush control, cleaning, 

weeding, and noncommercial improvement cuts; fire, 

insect, disease, and mammal protection; pre-commercial thinning; prescribed burning; and pruning 

(Cox 1984, Briggs and Condrell 1980), The procedures permitted under current (1986) law are discussed first, followed by an analysis of how these 

will be changed beginning in 1987 under provisions 

of the 1986 Tax Reform Act. 

Current Expensing Law 

Under current law, silvicultural and related 

costs associated with intermediate stand management may be deducted in full from ordinary income 

from any source (expensed) in the year they are 

incurred. If the costs are associated with a timber business, they may be deducted on Schedule C 

or Schedule F of Form 1040, or on the appropriate 

corporatg or partnership schedules, as a business 

expense. If the deductions result in a loss, the 

loss may generally be carried forward to offset 

income in a subsequent tax year. Property taxes 

and interest are also fully deductible for timber 

busdnesses each year. 

Somewhat different rules apply to timber investments. If silvicultural and related costs are 

associated with a timber investment, they may be 

deducted only as a "miscellaneous itemized deduction*' on Schedule A of Form 1040.~ To utilize 

this procedure, however, the taxpayer must itemize 

dcductions on his or her tax return. In years 

when deductions are not itemized, such costs must 

'sections 161-162 of the Internal Revenue Code 

allow both corporate and individual businesses to 

deduct all "ordinary and necessary expenses." 

7~he authority in Section 212 of the Internal 

Revenue Code, relating to expenses of producing 

income from, or in managing and conserving, nonbusiness investment type property held by individuals. Section 212 contains language similar 

to that in Sections 161-162. 

be capitalized or they will be permanently lost. 

Property taxes and interest are also fully deductible each year for timber investors who itemize 

their deductions. 

It is beyond the scope of this paper to discuss 

the complex differences between a timber investment and a timber business. There are no clear 

rules. Nevertheless, it can generally be said 

that a business entails considerably more activity 

than does an investment. However, extensive silvicultural practices alone do not equate to a 

business -- other factors also have to be considered. In the final analysis, each individual 

situation stands on its own and must be examined 

separately to make the distinction. 

To expense timber related costs, it is not 

necessary that the property be currently producing 

timber income. The owner, however, must have a 

profit motive. The Internal Revenue Service (IRS) 

will automatically assume such a motive and not 

question legitimate deductions if there is a 

profit in at least 2 out of every 5 consecutive 

years.G Failure to meet this standard, however, 

is not necessarily indicative of the lack of a 

profit motive. The term "profit" can be limited 

to appreciation in value and is the criterion 

often used for timber activities that may produce 

no income for periods of many years. 

Changes Made by the 1986 Tax Reform Act 

Beginning in 1987, the procedures described 

above will be drastically changed for certain 

taxpayers by provisions of the 1986 Tax Reform 

Act. The new rules applicable to expensing of 

silvicultural and related costs associated with 

intermediate stand management pertain to three 

categories of taxpayers (Siegel 1987). These are: 

(1) active timber businesses, (2) active timber 

investors, and (3) passive participants in either 

a timber investment or a timber business. 

Active Timber Business 

All silvicultural and related costs, including 

property taxes and interest, will be fully deductible each year as incurred against income from any 

source. There are no changes from prior law. 

Active Timber Investor 

The expensing of silvicultural and related 

costs, property taxes, and interest will each be 

treated differently for active timber investors. 

Silvicultural and related costs will be deductible each year against income from any source 

only to the extent that -- when added together 

with the taxpayers's other "mlscePlaneous itemized deductions" -- the total exceeds 2 percent 

of adjusted gross incoare. To the extent that 

test cannot be met, such expenditures must either 

 his is popularly termed the *'hobby loss rule." 

Under the 1986 Tax Reform Act, efcective in 1987, 

the rule will require a profit in at least 3 out 

of every 5 consecr~tive years. 
be capitalized or lost. The deductibility of 

interest attributable to indebtedness associated 

with a timber investment has also been severely 

curtailed. Such interest will be deductible each 

year only to the extent of the taxpayeras total 

investment income (timber plus nontimber) for that 

year. It may no longer be used to offset income 

from other sources in years when there is no 

investment income. Unused interest deductions, 

however, may be carried forward indefinitely to 

subsequent tax years in which there will be 

investment income. With respect to property 

taxes, there are no changes from prior law. Timber investors may continue to expense property 

taxes in full each year as an itemized deduction 

against incorne from any source. 

Beginning in 1987, the distinction between a 

timber business and a timber investment will 

unquestionably become more significant with 

respect to the expensing of timber related costs. 

Currently, it is not knom how the IRS will 

address the question. It may promulgate specific 

regulations directed to timber activities or continue to rely on the general law to make the distinction. 

Passive Participant 

Passive participants in a timber business or 

investment will be faced with Eomidable expensing 

restrictions. SilvSeultural and related costs, 

property taxes, and interest will all generally be 

deductible each year only to the extent of passive 

income (total from all sources) during that year, 

None of these types of expenditures may be used to 

offset nonpassive income except in the case of 

certain closely held corporation^.^ The new limitations generally apply in full to tax years 

beginning after 1986. However, a 5 year phase-in 

is provided for passive interests already held on 

the date of enactment sf the new tax law. Under 

the phase-in rules, partial deductions will be 

allowed from 1987 through 1990, with full exelusion beginning only in 1991. 

How does active involvement differ from a passive interest? The answer is not yet clear 

because the IRS has yet to write the regulations 

interpreting this section of the new law, It 

has, however, indicated that the forthcomfng 

regulations will specifically address timber 

holdings. The legislation does state that active 

participants musr materially participate in the 

activity and that material part%eipation must 

include active involvement in ~aking management 

decisions on a regular, contiausus, and substantial basis. 

9~losely held C corporations that are not personal service corporations may offset passive 

losses (deductions) against net active income in 

addition to passive income, but not against portfolio income. A closely held C corporation Is 

any C corporation in which more than 50 percent 

of the stock yalue is amed by five or fewer individuals during the last half of the tax year. 

CONCLUSION 

Just as with prior law, the federal income tax 

status under the 1986 Tax Reform Act of some 

silvicultural and related expenditures is clear 

and the status of certain other such costs is not. 

Also, as under previous law, the correct or optimal method of handling such expenditures for tax 

recovery under the new legislation depends on a 

number of different factors. These include the 

nature, timing, and purpose of the practice or 

cost; the taxpayeres cash flow situation; his or 

her tax status; and the available tax options. 

With respect to the costs associated with intermediate stand management, the preferred status 

under the new law seems to be an active participant in a timber business. Many nonindustrial 

woodland owners, however, will not be able to 

qualify for this classification. Some will 

undoubtedly lose deductions altogether or at best 

have to postpone them to future years. When 

coupled with the much higher taxes on timber 

income that will prevail beginning in 1987, this 

situation will certainly mean that less silvicultural work will be performed in the nonindustrial 

sector. In order to minimize the negative impacts 

of the new restrictions on expensing of silvicultural and related costs, proper planning will be 

more important than previously. The key will be 

to know the technical facts of each silvicultural 

operation, to be cognizant of the changes made by 

the new law and how they apply to each taxpayer's 

personal and forestry situations, and to then 

interphase the two for maximum advantage. 

LITERATURE CITED 

Brlggs, Charles W.; Condrell, William K. Tax 

treatment for timber capital gain and loss. 

Forest Farmer. 39(5):73-82; 1980. 

Cox, David B., editor. Energy resources tax 

reporter, Vol. 1. Ernst and Whinney in cooperation with Commerce Clearing House, Inc., 

Chicago; 1986. 5,169 p. 

Siegel, William C. Federal income tax treatment 

of silvicultural costs associated with young 

pine stands. In: Shoulders, Eugene, ed. Proceedings, third biennial southern silvicultural 

research conference. 1984 November 7-8; Atlanta, 

CA. Gen. Tech. Rep. SO-54. Washington, D.C.: 

U.S. Department of Agriculture, Forest Service; 

1985:183-189. 

Siegel, William 6. Implications of the 1986 

Federal Tax Reform Act for forestry. In: Proceedings, Society of American Foresters 1986 

annual convention; economics, policy and law 

working group technical session; 1986 October 8; 

Bimingham, AL. Washington, D.C.:Society of 

American Foresters; 1987: - . 

U.S. Department of Agriculture, Forest Service. A 

guide to federal income tax for timber owners. 

Agric. Handb. 596. Washington, D.C.:U.S. Department sf Agriculture, Forest . Service; 1982. 74 p . 
PRODUCTION AND COSTS OF THE BELL MODEL T 

FELLER-BUNCHER 1 

Joe McNeel and W. Dale Greene 2 

Abstract.--The Bell Model T feller-buncher is a tricycle-frame machine which employs a chainsaw felling head attached to a dangle boom. Although unable to hold a 

severed tree upright, the machine is adept at bunching all but the largest trees which 

it can cut. Results of a production study of the Bell Model T equipped with a 24 inch 

felling saw are presented illustrating the effects of stand parameters on machine performance and costs. 

INTRODUCTION 

The Bell Hodel T is one of several recently 

introduced feller-bunchers designed to eliminate 

shear-related damage in harvesting sawtimber. 

The unit uses a chainsaw felling head, rather 

than the more conventional hydraulic shear, to 

fell trees up to 24 inches in diameter at groundline. The chainsaw head eliminates the occurrence 

of compression damage and splits that commonly 

result when using shears. 

Unlike other saw type feller-bunchers, the Bell 

requires a low capital investment. This appeals 

to many loggers faced with the choice of either 

buying a saw type feller-buncher or using sawyers 

to fell sawtimber size trees. 

Because the Bell is relatively new in the United 

States, a study was undertaken to determine its 

production and cost characteristics under typical 

operating conditions. 

MCHINE DESCRIPTION 

The Bell Model T is a tricycle wheel carrier 

combined with a hydraulic powered chainsaw head. 

The three wheeled carrier manufactured by Bell is 

very similar to the Mor-Bell feller-buncher 

(Stokes et al, 1982). A summary of the machine 

characteristics are presented below. 

Bell Carrier: 

Length: 189 inches 

Zidth: 104 inches 

Engine : 70 NP Deutz, air-cooled 

Height : 105 inches 

Turning Radius : 189 inches 

Tire Size: 23.1 x 26 

Ground Clearance: 22 inches 

l~resented at the Fourth Biennial Southern 

Silviculture Research Conference 

2~xtension Timber Harvesting Specialist, The 

University of Georgia Cooperative Extension 

Service, Tifton, GA and Assistant Professor of 

Forestry, School of Forest Resources, The 

University of Georgia, Athens, GA 

Bell Felling Head: 

Type: Directional Chainsaw (270' Rotation) 

Felling Capacity: 24 inches Diameter at 

Groundline 

Bunch Capacity: 1 Tree per Turn 

STUDY METHODS 

The Bell Model T was observed during July 1986 

while felling for a production logging operation 

owned by the Gray Lumber Company of Waverly, VA. 

The logging company operation had used the Bell 

for approximately 3 months prior to the study. 

System production averaged between 80 and 120 

cords per day during the study with felling performed exclusively by a single Bell machine. 

The study site was located in Sussex County, 

VA and was typical of the lower coastal plain 

with less than 5 percent slope. Six plots were 

installed on the site prior to harvest. Plots 

were of a variable size, but usually covered an 

area of approximately 1 acre. Trees in each 

plot were measured to determine location within 

the plot and DBH. Trees were given unique numbers 

for identification during the time study of felling 

activities. Trees from each plot were subsampled 

for total height and diameter at groundline (DGL). 

The harvested stand was loblolly pine of natural 

origin, averaging 100 trees per acre. Trees 

ranged in diameter from 6 to 24 inches DBH and 

averaged 13.3 inches. total height averaged 70 

feet. A sumary of collected plot data is provided in Table 1. 

Table 1.--Stand characteristics measured from the 

study plots. 

KO. of Std. 

Variable Obs. Mean Dev . DBH (inches) 322 13.28 3.29 

DGL (inches) 

Ttl. Height (f t) 

VolumelTree (f t3) 

A video camera equipped with an internal stopwatch was used to record the Bell during felling. 
activities. The recorded videoiapes were later 

viewed to obtain elapsed function times and associated tree numbers within each plot. 

Four elements of the machine work cycle were 

identified. These included: (ijmove to tree, 

(2)positon and sever, (3)bunching, and (4)bunch 

maintenance. 

Statistical analysis of the time study data was 

conducted using linear regression techniques to 

produce prediction equations for elemental times. 

A total cycle equation was then developed by 

adding the elemental equations. Hourly ownership and operating costs of the Bell were estimated using market prices during the summer of 

1986 with the machine rate approach described 

by Miyata (1980). 

RESULTS 

A total of 322 cycles were analyzed. The time 

required for the position and sever element averaged 0.159 minutes per tree, while the move to 

tree element averaged 0.255 minutes per tree. 

Bunching averaged 0.124 minutes per tree for 320 

observations and bunch maintenance averaged 0.313 

minutes per bunch for 21 observations. A summary 

of the elements observed in the study is provided 

in Table 2. 

Table 2.--Summary of elemental cycle data for the 

Bell Model T. 

Std. ---Range--- 

Number Mean Dev. Min. Max. 

Element of Obs. ----- (minutes per tree)---- 

Position 

and Sever 322 0.159 0.083 0.051 1.123 

Move to 

Tzee 322 0.255 0.178 0.043 1.228 

Bunch 320 0.124 0.092 0.033 0.652 

Bunch 

Haintenance 21 0.313 0.158 0.123 0.625 

Position and Sever Element 

The time required to position and fell a tree 

during the study was relatively constant for 

trees of less than 20 inches DBE (Fig. 1). Trees 

20 inches or larger required approximately twice 

as much to fell. 

Observations indicated that, at a groundline 

diameter of 24 inches (DBH of approxinately 21 

inches), the felling head must be repositioned 

on the tree in order to make a complete cut. 

Tho machine is thus required to perform the 

posStion and sever element twice when falling 

trees over 21 inches at DBH. 

6 7 8 9 10 11 12 13 14 15 16 17 18 19 21 22 

DBH (inches) 

Figure 1.---Comparison of mean position and sever 

times by DBB class. 

Regression analysis of the position and sever 

data produced a przdiction equation based on 

DBH~. No other variable was found to be signif icant in the analysis. The prediction equation 

for the position and sever element follows: 

r2 =0.1760 F-Value=67.93 

Where : 

PS = Position and sever time (minutesltree) 

DBH = Diameter at breast height (inches) 

The F-value for DBH was significant at the 

0.001 level, suggesting that DBH is a good estimator for position and sevzr times. However, the 

low r2 value indic~tes a high level of variability 

in the data that cannot be explained by the prediction equation. 

Move to Tree Eleaent 

Move to tree elemental times were also modeled 

with a regression estimator. Move distance proved 

most sigl-~ificant in the regression analysis and 

wss used to develop a prediction equation. The 

equation for estimating move to tree element 

times follows: 

MT = 0.1409 + 0.003196 (DLST) 

r2 = 0.1885 F-Value = 61.55 

W'ner~: 

MT = Kove to tree time (minutes/tree 

DIST = Distance between trees (Teet) 
Although distance was highly significant in 

explaining variability in between tree noveaent , the data was too variable to produce a high r2 

value. So other variable tested reduced ;,love 

time variability in a significant manner. 

To make the prediction equation more useful, 

the variable DIST was replaced by a variable 

approximating between tree distance in terms of 

stand density, as suggested by Ashmore and others 

(1983) in a similar study. The resulting equation follows: 

MT = 0.1409 + 0.6670(~)-1 

\%%ere : 

NT = Xove to tree time (minutes/tree) 

X = Stand density (trees/acre) 

Bunch Maintenance- Element 

Bunch maintenance occurred only 21 times in 322 

observed cycles. No variable in the study significantly accounted for variability in this data 

'Lnd it was not possible to predict when this element would occur. As a result, a weighted mean 

was used to account for bunch maintenance within 

the total cycle. 

Approximately once every 15 turns, bunch rnaintenance occurred and Lasted an average of 0.32 

minutes. Kith a weighted mean apprcach, 0.019 

minutes were added to the total cycle time to 

account for bunch maintenance. 

Total Cvcle Time 

Bunch Element 

Mean bunch times continuously declined as tree 

size increased, suggesting that large diameter 

trees were not bunched. A graph of mean bunch 

times by DBH indicates that trees of 13 inches 

at DBW and larger required less than 0.08 minutes to bunch (Fig. 2). The Bell, weighing less 

than 12,000 Ibs., was unable to manipulate the 

larger diameter trees into multiple stem bunches 

.05 ' I 

6 1 B 9 10 I1 12 15 14 15 16 17 18 19 20 21 22 

DBN (inches) 

Figure 2.--Cornparison of mean bunch times by 

DBM class. 

The bunch element proved too variable to predict with regression. Instead, a mean of 0.124 

minutes per tree, derived from the study data, 

was used to estimate bunch times in the machine 

cycle. 

A prediction equation estimating total cycle 

time was developed by combining elemental time 

estimators. The predictian equation requires 2 

input variables, DBH and stand density, to predict individual cycle tixes. The prediction 

equation for total cycle time follows: 

TC = 0.36996 + 0.6770(~)-3 + 0.0003983j~~~)~ 

Where: 

TC = Total cycle time (minutes/tree) 

N = Stand density (trees/scre) 

DBH = Diameter at breast height (inches) 

This equation was used with measures of stand 

density and average stand diameter to predict the 

range of productivity for the Bell. The graph in 

Figure 3 illustrates this range based on stand 

values ranging from 6 to 22 inches. 

6 E 10 12 14 1E 18 20 22 

Mean DBH (Inches) 

Figure 3.---Predicted production rates for the 

Bell Model T. 
COST ANALYSIS 

A cost analysis of the Bell was conducted using 

the prediction equation for total cycle time and 

an hourly cost estimate based on current cost data. 

The analysis incorporated the machine rate to develop hourly cost estimates for the unit. Hourly 

ownership and operating costs estimates for the 

Bell Model T were based on machine rate calculations: 

Assumptions : 

Purchase Price: $15,000 

Salvage Value: $11,000 

Economic Life: 3 years 

Utilization: 65 percent 

Scheduled Machine Hrs (SMWrs) per Yr: 2000 

Productive Machine Hrs (PMHrs) per Yr: 1300 

Ownership Costs: 

Depreciation: $11.28 

Taxes, Interest and 

Insurance (25 pct. of AVI) 7.76 

Total Ownership Costs: $19.04 per PMHr. 

Operating Costs: 

Fuel (1.75 GPH @ $0.50/gal.) 0.88 

Lube, oil and filters 

(30 pct. of fuel cost) 0.26 

Repair and maintenance 

(60 pet. of depreciation) 6.77 

Labor ($7.50/sched. hr. and 

36 pct. fringe benefits) 15.70 

Total Ownership Costs $23.61 per Pmr. 

$27.72 per Si$Hr. 

Cost of per cord prediction for the Bell were 

developed based on hourly productive cost estimates (Fig. 4). As average stand diameter increases, the cost of harvesting with the Bell is 

projected to decline. In contrast, little change 

in cost occurs relative to stand density. 

J 1 

6 8 10 12 14 16 18 20 22 

Mean DBN finehesf 

For example, harvesting a stand of timber averaging 500 trees per acre with a mean DBR of 6 

inches was estimated to cost $5.15 per cord, A 

stand averaging 50 trees per acre with a mean DBH 

of 12 i~ches was estimated to cost $1.70 per cord, 

a decrease of more than 65 percent in per unit 

costs. 

CONCLUSIONS 

The Bell Model T is a unique feller-buncher designed as a low cost alternative to conventional 

feller-bunchers using hydraulic shears. The unit 

worked effectively in pines ranging in size from 

6 to 22 inches at DBH during a time study analysis. 

Elemental and total cycle predictors were developed from the time study data. Production 

estimates suggest that production rates for the 

Bell are most affected by stand diameter. 

The cost and production analysis results suggest 

that the Bell would not be as effective in thinnings or in clearcuts where the average stand 

diameter falls much below 10 inches at DBH. 

Costs ranged between $0.50 and $2.00 per cord 

for stands with an average diameter greater than 

10 inches in DEN, but increased to over $5.00 

per cord in stands averaging less than 8 inches 

DBH. 

LITERATURE CITED 

Ashmore, Colin, Stokes, B.J. and Lanford, B.L. 

1983. Thicning Performance of the Hydro-Ax 

411 in Fifth Row Removal. Paper presented at 

the 1983 ASEA @inter meeting. Paper No, 83-1604. 

19 p. 

Miyata, E.S., 1980. Determining fixed and operating costs of logging equipment. USDA For. Serv. 

Gen. Tech. Rep. KC-55. 

Stokes, B.J., B.L. Lanford, and D.L. Sirois. 

1982. Nor-Bell thinning system: feller-buncher, 

skidder, and loader. ASAE Paper 82-1590. 

Winter meeting, her. Soc. Agri. Eng., Chicago, 

IL, 12 p. 

Figure 4.--Cost predictions for the Bell Kodel T. 
PRODUCTIVITY AND COST OF GRAPPLE SKIDDERS 

PERFORMING GATE DELIMBING 1 

R. A. Tufts, D. L. Sirois, and B. J. Stokes 2 

Abstract.--Time study data were collected on six 

different types of rubber-tired, grapple skidders 

performing skidding and gate delimbing. Regression analysis was used to develop a model to predict total cycle time. The total cycle time 

model was used to demonstrate the importance of 

the variables affecting productivity. Cost per 

cord was calculated for each of the six machines. 

INTRODUCTION 

Timber harvesting is a silvicultural tool as 

much as site preparation and timber stand improvement. To effectively use this tool the forest 

manager must understand the factors that affect 

the cost and productivity of timber harvesting. 

The value of a stand of timber is the residual 

of delivered price less harvesting cost. To 

maximize the value of the timber, harvesting 

costs must be minimized. The only way to reduce 

costs is to understand the variables that affect 

harvesting and plan operations to minimize the 

cost of these variables. 

Timber harvesting methods have evolved from 

labor-intensive, low-capital systems to highly 

mechanized, highly capitalized systems. This 

change has been brought about by the decline in 

the availability of woods labor and the need for 

increased productivity. A recent survey (Weaver 

et al. 1981) indicated that slightly less than 

two-thirds of all pulpwood harvested by independent contractors was produced by 25 percent of 

the contractors because of the increase in 

mechanized operations. 

The most common inwoods system for mechanized 

timber harvesting operations in the South consists of feller-bunchers; rubber-tired, grapple 

skidders; and delimbing gates. This system is 

highly productive because of the equipment, and 

relatively safe because no manual operations are 

performed in the woods. 

In-woods transportation and delimbing are performed by the skidder. Multiple trees are 

placed in a bunch by the feller-buncher. The 

bunch is transported to the log deck by the 

skidder with an intermediate stop at the 

delimbing gate. The delimbing gate consists of 

Figure 1.--A grapple skidder load being backed 

through a delimbing gate. 

a grid assembly made of pipe. The trees are 

backed through the gate to break the limbs off 

the stem (~igure 1). 

The high degree of capitalization and 

increased competition create the need for careful analysis of harvesting operations. Analysis 

is even more important when using a skidder for 

gate delimbing because load sizes must be 

smaller. Stokes and Lanford (1985) reported 

that it was feasible to gate delimb only small 

loads when thinning young pine plantations. 

LITERATURE REVIEW 

'presented at the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

GA, November 4-6, 1986. 

'~ssistant Professor, Auburn University; Project 

Leader and Research Engineer, U.S. Department of 

Agriculture, Forest Service, Auburn, AL 36849. 

Variables that affect skidder productivity can 

be divided into three categories: machine 

variables, load variables, and stand variables. 

The most important variables affecting skidder 

productivity are load size and skid distance. 

Tufts (1977) and Plummer (1977) tabulated 

skidder productivity according to skid distance 
and tree size, Fowler (1972) derived a prediction equation based on skid distance, volume per 

acre, and grapple payload. Gardner (1978) determined that the principal variables affecting 

cycle time for skidders were skid distance, 

number of logs or load size, and weight of the 

machine, 

A comprehensive list of variables was compiled by Sampson and Donnelly (1977). They 

listed skid distance, horsepower, maximum speed 

in each gear, percent slippage of wheels, volume 

per acre, number of pieces to be skidded per 

acre, density of the residual stand, slope, and 

soil surface conditions as variables that affect 

skidder productivity. The current use of wider 

tires in skidding operations can also affect 

skidder productivity (Rumer and Sirois 1984). 

Lanford and Haver (1973) developed a series of 

prediction equations based on skid distance, 

machine size, slope, dbh, volume per acre, and 

soil conditions. Liu (1981) found that brushiness, obstacles, and the number of stems per 

load did not significantly affect production. 

He identified horsepower, skidder weight, load 

volume, slope, and skid distance as the primary 

variables in predicting skidder productivity. 

Time study data were collected on six different types of rubber-tired, grapple skidders 

performing skidding and gate delimbing. Each 

cycle was divided into the following elements: 

travel empty, grapple, travel loaded-full tree, 

gate delimbing, travel loaded-tree length, and 

ungrapple. Individual elements were timed and 

the elemental times were added to produce the 

total cycle time, 

Independent variables measured for each cycle 

cdnsisted of machine, load, and stand variables. 

Machine variables considered were weight, horsepower, and a ratio of weight divided by 1,000 

divided by horsepower, toad variables measured 

were weight, volume, average volume per tree, 

basal area, average basal area per tree, number 

of trees and number of bunches. Stand variables 

recorded were skid distance, slope perpendicular 

to the contour, direction of travel in relation 

to slope, brush conditions, and soil strength, 

Linear regression analysis (Draper and Smith 

1967) was used to develop a model to predict 

total cycle time as a function of the independent 

variables, Correlation coefficients were calculated to identify the most significant variables 

affecting cycle time. Models were developed by 

starting with the independent variable that 

explained the most variation. Then, successive 

variables and interaction terms were added until 

the addition of another variable would not significantly improve the model as measured by the 

partial P-statistic , 

The best model was used to determine the effect 

sf the significant variables on time per cycle 

and productivity. Time per cycle was generated 

by the model. Productivity was calculated as the 

cords skidded and delimbed per scheduled machine 

hour. To calculate productivity, load size in 

pounds was divided by 5,400 pounds per cord and 

multiplied by the number of cycles per scheduled 

machine hour (SMH), based on 75-percent utilization, 

Cost per cord as a function of load size was 

calculated for each of the six types of machines. 

Productivity for each machine type was calculated 

with the model using a skid distance of 650 feet 

and the machine's ratio, the average number of 

bunches and range of Load sizes. 

Machine costs were calculated using the machine 

rate method (Miyata 1980). List prices were 

obtained from Local equipment dealers. Depreciation was calculated on a straight line basis, 

using a 5-year life and 20-percent salvage value. 

Annual interest, insurance, and taxes were based 

on 18 percent of the average annual investment. 

Fuel costs were $1.00 per gallon and usage was 

based on 0.028 gallons per horsepower-hour 

(Plummer and Stokes 1983). Lubrication costs 

were 30 percent of fuel cost. Maintenance and 

repair costs were estimated to be 80 percent of 

depreciation. Fuel, lubrication, maintenance and 

repair accumulate on a productive machine hour 

(PMH) basis and were converted to a scheduled 

machine hour basis by multiplying by the utilization rate. Labor including fringe benefits 

totaled $9.10 per SMH. The machine rate was 

divided by the productivity as a function of load 

size to obtain the cost per cord, 

RESULTS 

The data set consisted of a total of 207 

cycles collected during 11 studies on six different types of machines. Machine types are 

listed in Table I. The independent variables 

measured and their averages and ranges are listed 

in Table 2. 

Table 1,--Machine types studied, their horsepower, weight, and number of observations, 

Machine Horse- Weight Number of 

type power ( lb ,I observations 

Timberjack 520" 185 29,000 4 2 

Tree Farmer C7 136 22, SO0 13 

Timberjack 380 136 20,508 15 

Caterpillar 518 130 25,300 3 5 

Franklin 170 121 22,340 46 

John Deere 540B 96 18,675 5 6 

aBrand names are Listed for the reader's benefit 

and do not constitute an endorsement by the 

authors or their organizations, 

Machine variables are constant for each machine 

and represent typical skidders in use on timber 

harvesting operations, 
Table 2.--Independent variables measured and 

their averages and ranges, 

Variable Average Range 

Hachine variables 

Weight, lb. 

Horsepower 

Ratio (wt/1000/~p) 

Load variables 

Weight, lb. 

Volume, cu. ft. 

Avg. Vol./tree 

Basal area, sq. ft. 

Avg. BA/tree 

No. of trees 

No. of bunches 

Stand variables 

Travel distance, ft. 

Slope 

Steepness, % 

Load variables exhibit a wide variation as 

would be expected. Load weight averaged 3,218 

pounds or about 0.6 cord, Ten percent of the 

loads were less than 0,3 cord, and only 8 percent of the loads were larger than l cord, The 

average basal area represents a tree 8.9 inches 

in dbh, with a range of 3.9 to 15.1 inches in 

dbh. The average number of bunches per cycle 

was 1.15; however, three of the machines never 

grappled more than one bunch, and only one 

machine grappled more than two. Since load size 

and number of bunches should be independent, any 

bunch size can be built; picking up more than 

one bunch represents inefficiencies for the 

skidder. 

Of the stand variables, only skid distance 

was significant. Skid distances as high as 

2,488 feet were observed, but 86 percent of the 

observations were less than 1,000 feet. Slope 

should affect skidder cycle times, but during 

this study most of the observations were on flat 

terrain; the average slope was only 5.5 percent 

with a maximum of 20 percent. Brush and soil 

conditions were assigned qualitative values, but 

the range of conditions observed were not sufficient for either of these to be significant. 

The model which best predicted total cycle 

time for rubber-tired, grapple skldders performing skidding and gate delimbing was as 

follows : 

Time/cycle = 7.237 - 0.009081 x Distance 

+ 0.001497 x Load 

- 30.79 x Ratio 

+ 0.05557 x Distance x Ratio 

- 0.006355 x Load x Ratio 

+ 0.001624 x Distance x No. Bunches 

- 0.000133 x Load x No. Bunches 

2 where: R =.51 

where: Distance = one-way skid distance, ft., 

Load = weight of the trees, lb., 

Ratio = machine weight/ 

1,00OJhorsepower, and 

No. Bunches = number of bunches per cycle, 

This equation contains one stand variable, 

skid distance; one machine variable, ratio, that 

considers both machine weight and horsepower; 

and two load variables, load size and the number 

of bunches. 

The effect of each of these four variables on 

time per cycle and productivity was calculated 

using the above model and the averages for each 

of the four variables. The averages were: skid 

distance, 650 feet; load size, 3,200 pounds; 

ratio, 0.18 (180 pounds/Hp); and number of 

bunches, 1.15. For the purpose of illustration, 

three variables were held constant and only one 

was changed. In actuality, load was significantly correlated with ratio and the number of 

bunches, and an independent comparison of these 

variables is not statistically correct. 

Skid distance over the observed range affected 

time per cycle more than the other variables 

(Figure 2). Estimated cycle times ranged from 

2.89 minutes at a 200-foot skid distance to 5.68 

minutes at a 1,200-foot skid distance. For each 

100 feet of additional skid distance, cycle time 

increased 0.28 minute. As cycle time increased, 

productivity decreased. The effect is not 

linear because the load in cords is multiplied 

by the reciprocal of cycle time. On the 

average, 75 percent of the cycle time was spent 

traveling, so skid distance would be expected to 

have a significant effect. In fact, skid 

distance alone accounted for 67 percent of the 

variability in the data. 

- Cycle f ime 112 

200 700 1200 

Skid distance, ft. 

Figure 2.--Time per cycle in minutes and production per scheduled machine hour (SMH) as a 

function of skid distance. 
Load weight can affect time per cycle by 

slowing the loaded travel speed of the skidder 

and by increasing the delimbing time (Figure 3). 

- Cycle Time 

- - Production 

Load weight, Its. 

Figure 3.--Time per cycle in minutes and production per scheduled machine hour (SMH) as a 

function of load weight. 

Cycle time increased 0.02 minute per 100 pounds 

of load weight. The relationship between load 

weight and production is almost linear because 

the increase in time is so small. Production 

increased by about 880 pounds, or 0.16 cord per 

100-pound increase in load weight. This figure 

demonstrates that load weight is the most important variable affecting skidder productivity. 

The number of bunches skidded increased the 

grappling time because of the additional movement - opening and closing the grapple and 

positioning the load (Figure 4). Since load 

- Cycle Time I12 - - Production 

Number of Bunches 

Figure 4.--Time per cycle in minutes and production per scheduled machine hour (SMH) as a function of number of bunches grappled. 

size is the most important variable affecting 

productivity, the skidder should transport the 

maximum load each cycle. Since the fellerbuncher can create any size bunch, picking up 

multiple bunches does not necessarily mean 

increasing load size. For this study, the time 

penalty associated with acquiring additional 

bunches for a full load versus picking up a full 

load from one bunch was more important, Picking 

up an additional bunch required 0.63 minute. 

(Building large bunches can decrease fellerbuncher productivity, so the machine limiting 

production or having the highest cost per unit 

of production should be f-avored when determining 

the method of operation.) 

To optimize skidder productivity, the correct 

size bunch should be built. Normally, a skidder 

operator will only grapple one bunch because two 

bunches would be too large a load. During this 

study, only one bunch was skidded per cycle 86 

percent of the time, and two bunches were 

skidded 13 percent of the time. Three and four 

bunches were picked up only once each; so, the 

linear effect for three and four bunches is 

probably not accurate. 

Ratio, representing the effect of the 

machine, also affects time per cycle and production (Figure 5). The effect is not pronounced 

- Cycle Time 

- - Production 

E 

t i I 

0.150 0.175 0.200 

Ratio (wt/1000/Mp) 

Figure 5.--Time per cycle in minutes and production per scheduled machine hour (SMH) as a 

function of ratio. 

and it is the opposite of what would be expected. 

As the ratio increased, time per cycle decreased, 

indicating that underpowered machines are more 

productive. This may be true when the machines 

are underutilized; maximum loads are never skidded. The smaller skidders have higher machine 

weight to horsepower ratios but are more maneuverable and cycle time may be reduced because of 

the maneuverability. 

Figure 6 depicts the load size for each type 

machine in study by horsepower. The vertical line 
represents the range in load sizes for each 

machine. The short horizontal Line intersecting 

the vertical line represents the average load 

size for that machine. As the figure indicates, 

load size decreased slightly as machine 

horsepower increased. This represents a 

significant underutilization of ehe larger 

machines, It was not possible to determine the 

reason from the data avai table, One possible 

explanation is the physical size of the gate. 

Large loads may be too wide to effectively 

delirnb using a gate, If this is the case, 

larger machines are not cost effective. 

I 

96 121 136 185 

Machine horsepower 

Figure 6.--The range in load size (vertical line 

and average load (short horizontal line) for eac 

machine type by horsepower (since two machines 

have 136 horsepower, one was moved slightly to 

the right). 

Although load size does not increase with 

machine size, it was postulated that the larger 

machines would travel faster with the same 

size load. This was not the case as shown in 

Figure 7, The plot displays the range and 

average Again, the larger machines do not show 

an improvement over the smaller machines. If 

the machines are under utilized, travel speed 

may be more a function of operator comfort and 

trail conditions than of machine size. 

Because the larger skidders were not more 

productive than the smaller ones, the cost per 

cord was calculated to identify the penalty 

associated with underutilizing a larger machine. 

The model was used to calculate productivity 

based on a skid distance of 650 feet and the 

range in load sizes depicted in Figure 6. 

Machine rates are calculated in Table 3. The 

machine rates were divided by productivity based 

on load size to produce Figure 8, a graph of 

cost per cord as a function of load size. 

Only the largest and smallest machines are 

depicted in Figure 8. The Timberjack 520, 

* 

96 121 136 185 

Machine horsepower 

Figure 7.--The range in travel-loaded speed 

(vertical line) and average travel-loaded speed 

(short horizontal line) for each machine type by 

horsepower (since two machines have 136 horsepower, one was moved slightly to the right). 

Load Size, 9bs 

Figure 8.--Cost per cord as a function of load 

size for the Timberjack 520 (TJ 520) and John 

Deere 540B (JD540). 

because it is a larger, more expensive machine 

and was no more productive than the smaller 

machines during this study, had the highest cost 

per cord. The John Deere 540B was the smallest 

skidder in the study and produced the lowest 

cost per cord curve. More than the difference 

between the machines, Figure 8 demonstrates the 

importance of load size. As load size decreases, 

costs increase at a faster rate. This same 

relationship was illustrated in Figure 3. 
Table 3.--Machine rate calculations (~iyata 1980) 

for the Timberjack 520 (TJ5201, Tree Farmer C7D 

(TFC~D), Timberjack 380 (T~3801, Caterpillar 518 

fC518), Franklin 170 (FK~~O), and John Deere 540B 

( ~~540). 

List Price $130,923 $86,865 $88,814 $101,838 $81,100 $82,000 

Average Annual Investment 89,028 59,068 60,394 69,250 55,148 55,760 

Depreciation 13.97 9.27 9.47 10.86 8.65 8.75 

Interest, Insurance and Taxes 10.68 7.09 7.25 8.31 6.62 6.69 

Labor 9.10 9.10 9.10 9.10 9.10 9.10 

Fue 1 5.18 3.81 3.81 3.64 3.39 2.69 

Lubrication 1.55 1.14 1.14 1.09 1.02 0.81 

Maintenance and Repair 11.17 7.41 7.58 8.69 6.92 7 -00 

Machine Rate 

CONCLUSION 

Planning timber harvesting operations to 

maximize profit requires a recognition of the 

factors that affect the operation. Load size 

is the most important variable affecting skidder 

productivity and skid distance is the most 

important variable affecting time per cycle. 

The correct bunch size should be built so the 

skidder is required to grapple only one bunch 

per cycle. Also, the timber harvester should 

recognize the limitations imposed by the system 

and not purchase equipment that is not cost 

effective . 

LITERATURE CITED 

Draper, N. R., and H. Smith. 1967. Applied 

regression analysis. John Wiley & Sons, Inc. 

New York. 407 p. 

Fowler, 0. S. 1972. A dynamic simulation model 

for timber harvesting systems in the Southern 

Coastal Plain. Ph.D. Dissertation. University 

of Georgia. Athens, GA, 153 p. 

Gardner, R. B. 1978. Turn cycle time prediction 

for rubber-tired skidders in the northern 

Rockies. U.S. Department of Agriculture Forest 

Serv. Res. Note INT-257. 5 p. 

Lanford, Be L., and G. F. Haver. 1973. 

Production tables study volume 4: analysis of 

production study data for the Sout5. American 

Pulpwood Assoc . , Harvesting Res . Pro j . Atlanta, GA, (unpubl.) 

Liu, C. Y. 1981. Development of a skidding 

module for a timber harvesting simulation 

model. M.S. Thesis. Auburn Univ., Auburn, AL. 

178 p. 

Miyata, E. S. 1980. Determining fixed and 

operating costs of logging equipment. U.S. 

Department of Agriculture Forest Serv. Tech. 

Rpt. NC-55. 16 p. 

Plummer, G. M. 1977. Harvesting cost analysis. 

In: Logging Cost and Production Analysis. 

Timber Harvesting Rpt. No. 4. Forestry and 

Harvesting Training Ctr. Long Beach, MS. 108 p. 

Sampson, G. R., and D. M. Bonnelly. 1977. 

Productivity of skidders in selection cuts of 

southwestern Ponderosa pine. U.S. Department 

of Agriculture Forest Serv. Res. Note RM-337. 

8 P* 

Plummer, G. M., and B. J. Stokes. 1983. 

Petroleum products consumption estimators for 

off-highway forest operations. American 

Pulpwood Assoc. Tech. Pap. 83-A-12. 10 p. 

Rummer, R. B., and D. L. Sirois. 1984. A 

preliminary assessment of tire-size effects on 

the productivity and site impacts of skidders 

operating on steep terrain. Amer. Soc, of 

Agric. Eng. Pap. No. 84-1619. 17 p. 

Stokes, B. J., and B. L. Lanford. 1985. 

Prebunching and skidding functions in 

thinnings. Amer. Soc, of Agric. Eng. Pap. No. 

85-1594. 9 p. 

Tufts, D. M. 1977. Planning a logging 

operation with analyses of some pulpwood 

logging systems. In: Logging Cost and 

Production Analysis. Timber Harvesting Rpt. 

No. 4. Forestry and Harvesting Training Ctr., 

Long Beach, MS. 108 p. 

Weaver, G. H., R. A. Kluender, W. F. Watson, W. 

Reynolds, and R. K. Matthes. 1981. 1979 

Pulpwood producer census Southwest and 

Southeast Technical Divisions of the American 

Pulpwood Assoc. Mississippi Agric. and 

Forestry Exp. Sta, Un-numbered Series, 11 p. 
Interactions and lnfluenees 

Moderator: 

Arnett C. Mace, Jr. 

University of Florida 

Hans ~iekerk~ 

...................................................... 

Abstract. -- Old-field slash pine flatwoods forest was 

harvested and regenerated with high and low levels of 

disturbance and compared against a control. All water 

table levels increased, but only the high disturbance 

treatment generated significantiy more runoff. Annual 

water balances were calculated using evapotranspiration 

data from a weighing lysimeter. ...................................................... 

INTRODUCTION LITERATURE REVIEW 

The hydrology of pine flatwoods in the coastal 

zone is mostly controlled by the poorly-drained 

condition of rather level soils often underlain by 

some irnpermeable layer. The high infiltration rate 

of these forest soils minimizes runoff until the 

water table comes near the surface and saturates 

the soil. Then surface runoff from seasonally high 

rainfall rapidly reaches the drainages and swamps 

resulting in a high ratio of stormflow to rainfall 

or R-index (Hewlett and Hibbert; 1967). Drainage 

improvement decreases the resistance to runoff and 

increases soil moisture storage capacity, and may 

generate more stormflow and baseflow at the cost of 

intermediate flow rates (Heath, 1978). Improved 

drainage deepens the aerated soil zone, but may 

cause droughty conditions in sandy hammocks. Some 

lateral recharge occurs from interspersed ponds to 

the water table of pine flatwoods during the dry 

seasons (Heimberg, 1984), but deep seepage to the 

groundwater aquifer is limited (Conover et al., 

1984). 

Stormflow is the quickflowing portion of runoff 

that exceeds baseflow. It derives from the direct 

precipitation on and increased discharge from the 

saturated soil expanding and contracting in extent 

during a storm event (Hewlett and Hibbert, 1967). 

Stormflow expressed as percent of rainfall is an 

index of the flashiness of runoff from landscapes. 

Stormflow is cumulative downstream in contrast to 

peakflow which becomes attenuated. Stormflow data 

is mostly used for engineering designs of channels, 

culverts, and dam stuctures. 

Evapotranspiration asserts priority demands on 

soil water and has potential for the manipulation 

of runoff water balances (Lull, 1964; Ponce, 1983). 

Transpiration is proportional to forest leaf area 

and rooting depth, while canopy interception of 

rainfall is related to leaf area, stand density and 

deciduousness. Evaporation from ground surfaces is 

less in the forest than in the open because of more 

shading and less air flow. 

lpaper presented at the Southern S i lvicultut a1 

Research Conference, Atlanta, GA, Nov. 4-6, 1986. 

'~ssociate Professor , Forest Hydrology, School of 

Forest Resources and Conservation, University of 

Florida, Gainesville, FL 32611. 

The above generalities have been discussed but 

precious little information has been published for 

poorly-drained landscapes. One project assessed the 

hydrologic and water quality patterns of triplicate 

small flatwoods watersheds in southeastern Arkansas 

(Beasley and Granillo, 1985). Clearcut harvesting 

increased water yields and peakflows significantly 

for the first year. Selection cutting did not show 

a difference between annual water yields based on 

the standard deviation of replicates. However, when 

pre-treatment annual water yield ratios are used in 

the analysis of post-treatment data, to account for 

the initial differences between watersheds, cutting 

effects become apparent. 

Runoff in poorly-drained pine flatwoods is mostly 

controlled by rainfall and degree of surface soil 

saturation as indicated by the water table level. 

This has been tested for flatwoods in south Florida 

showing a reasonable correlation (Konyha et al., 

1982). 

The rainfall and water table depth above mean sea 

level were used to predict peakflow from a forested 

coastal watershed (Williams, 1979). The resulting 

equation appeared to support the theory of variable 

source areas for runoff (~ewlett and Hibbert, 1967) 

in that stormflow is initiated when the watertable 

reaches the bottom of drainages and then increases 

proportional to the expanding area of the saturated 

soil. Partial cutting in other but similar sites 

caused water table rises averaging 1.1 ft (Williams 

and Lipscomb, 1981). Responses to most harvesting 

treatments persisted for another year, but became 

in part amplified by the drought period when water 

tables of the fully forested controls were farther 

drawn down by evapotranspiration. 

Data from another but very poorly-drained coastal 

watershed showed a very similar peakflow equation 

(Rodriguez, 1981). However, during the first year 

of clearcut harvesting and regeneration not much 

more runoff was generated, which supports the above 

observation that the response of water table levels 

to tree removal is proportional to the water table 

depth (Langdon and Trousdell, 1978; Williams and 

Lipscomb, 1981). This proportionality has only been 

correlated with the water supply for and demand by 

the remaining vegetation, but may also be explained 

in part by the drainable porosity (Williams, 1978) 

which reduces with depth. 
Optimm water table depth for tree growth was in 

the lower rooeing zone (Mhite and Pritchett, 1970) 

and was strongly affected by micro-relief (~orio 

and Wodges, 1971). W highly fluctuating water table 

created periodic anoxic soil or drought conditions 

reducing annual tree growth, Cypress pond drainage 

decreased average water levels but increased the 

seasonal fluctuations (~ickers, 19801, suggesting a 

possible negative effect on tree regeneration and 

growth, 

Irrigation of an isolated cypress pond with waste 

water showed some overflow to occur during the late 

er and winter seasons, but most water slowly 

percolated into the surrounding soils (Heimburg, 

1984). Evapotranspiration as measured from daily 

waterlevel fluctuations was found to be controlled 

mainly by the deciduous canopy, averaging about 

0.16 inchlday during the growing season. 

Stormflow runoff as a proportion of its rainfall 

(R-index) has been proposed to describe the major 

storms contributing to downstream flooding (Hewlett 

and Hibbert, 1967). Mapping of such data for the 

Georgia coastal plain showed the poorly-drained 

pine flatwoods to yield more than 16% of rainfall 

in stormflow, while the inland deep sands showed 

stormflow to be less than 4% of rainfall (Woodruff 

and Hewlett, 1971). Stormflow data from the above 

very poorly-drained coastal watersheds showed the 

response to be 26% regardless of forest treatment 

(~adri~uez, 1981). 

Evapotranspiration has not been measured for the 

coastal pine flatwoods forests. Transpiration was 

measured using plastic airflow chambers and used in 

a simulation model resulting in about 40 inch/year, 

excluding interception (Golkin, 1981). Interception 

ranges from 4-40 pct of annual rainfall depending 

on tree density (Burger, 1979; Riekerk and Korhnak, 

1984). Evapotranspiration of cypress swamps was 

estimated from water fluctuations at 33 inch/year 

(Heimberg, 1984), but transpiration was measured at 

about 50 inch/year (Brown, 1981). 

METHODS 

An ongoing cooperative and integrated study of 

ecological and environmental consequences of pine 

flatwoods intensive forest management practices was 

initiated during 1976. The study site was 25 miles 

northeast of Gainesville, FL, in the large Bradford 

Forest of a cooperating industrial timber company. 

The climate is characterized by 55 inches of evenly 

distributed rainfall with some dry periods in the 

spring and fall seasons (Dohrenwend, 1978; Jordan, 

1984). Mean temperature is 70 F, averaging 57 F in 

the winter and 81 F in the summer. Droughts occur 

every 4 years with severe conditions every 7 years. 

Pan evaporation is 66 incheslyear. 

The area was in old-field pine flatwoods forest, 

containing 20-402 cypress ponds, and interspersed 

agricultural lands. The dominant canopy trees were 

slash pine (Pinus elliottii Engelm. ) with scattered 

longleaf pine (P. palustris Mill.) on the better 

drained flatwoods sites, and bald cypress axod odium 

distichum (L.) Rich.) mixed with sweetbay (~agnolia ' *' L.), sweetgum (Liquidambar styraciflua 

L.) and red maple (Acer rubrum L,) in the ponds. 

Understory shrubs were dominated by sawpalmetto 

(Bartr.1 Small), ga 

ay) and fetterbush ( 

(Lam. ) K Koch) . 

The soils are the Stilson series (Arenic Plintbic 

~aleudult) in flatwoods and Mascotte and Surrency 

series (Ultic Haplaquod) in ponds. The sandy soils 

are underlain by a slowly permeable clay layer (Ks 

= 0.03-0.3 inchiday) about 8 ft thick with sandy 

gaps leading into the Hawthorn Formation of sand, 

clay and limestone layers (Pratt, 1978). The Ocala 

Group below this formation is the main water supply 

aquifer for the region, 

Three watersheds (WSl= 165 acres, WS2= 120 acres, 

WS3= 346 acres) were isolated by road-dikes with 

interior ditches leading to longthroated recording 

flumes (Replogle et al., 1978). About 40% of WS1, 

24% of WS2, and 47% of WS3 were in cypress ponds. 

All pond and water table wells had recorders, and a 

raingauge network supplemented the central weather 

station. Soil moisture was measured with a neutron 

probe at 6 and 18 inch depths adjacent to selected 

recording wells. Depth of rust on steel rods at the 

same sites was measured seasonally (McKee, 1978). 

Daily evapotranspiration was measured with a 10- 

ton weighing lysimeter within a pine plantation at 

the Austin Cary Forest near Gainesville (Riekerk, 

1982). A nearby weather station provided data to 

relate potential to actual evapotranspiration for 

use at the Bradford Forest. 

After a year of pre-treatment calibration 49 pct 

of WS1 was harvested and regenerated with minima 

disturbance, which included shortwood harvesting, 

chopping, bedding and planting. About 74 percent of 

WS2 was machine harvested, and burned, windrowed, 

harrowed, bedded and planted. The 40-year old-field 

forest of WS3 was left undisturbed as a reference. 

Hydrologic analyses fallowed standard procedures 

developed for paired watershed data (Swindel and 

Douglass, 1984; Hewlett and Doss, 2884). The change 

between pre-treatment and post-treatment regression 

slopes was calculated for each year and tested for 

significance. 

RESULTS AND DISWSSION 

Water tables 

The water table data have been plotted in Figure 

1 and show a significant rise in the two treatment 

watersheds after harvesting in November 1978. The 

effect was greater when the water tables were down, 

and diminished only gradually. The pre-treatment 

calibration data had a high correlation coefficient 

of 0.94, but the treatments increased variability 

of infiltration and water table recharge, and which 

became compounded by a slow rewetting of airpockets 

created deep in the soil by the drought, The first 

year data show less of a response under the maximum 

disturbance treatment which is possibly due to less 

infiltration into the machine compacted soil. The 

water tables after treatment remained higher than 

in the control. However, the control forest could 

have lowered the water table because of continuing 

stand development and increased water use, 
Figure 1. Weekly water table fluctuations. 

Soil moisture had some relationship to the depth 

of the water table. Examination of scattergrams 

showed soil moisture at 0,5 ft depth to decrease 

from 20 to 8 percent (by weight) with the water 

table dropping to 2.5 ft, but any further drop did 

not change the moisture content very much. The soil 

moisture at 1.5 ft depth showed no correlation with 

the water table level unless it fell below 2.5 ft 

causing moisture to decrease 3.3 percent per ft of 

drop down to 4 ft depth. These data suggest that 

the moisture content of the sandy soil is related 

to water table depth only when within a few feet. 

The unsaturated zone has an oxidizing atmosphere 

which can be used to indicate mean seasonal water 

table depth. Depth of rusting (R ft) of steel rods 

adjacent to some recording wells was predicted by 

R = 0.37 + 0.36 WT (CV = 0.48 and SD = 0.3 ft). The 

fluctuating water table in the sandy soil averaged 

2.3 ft depth with a large variability of oxidizing 

conditions during the seasonal observation periods. 

The data published for heavier organic-rich coastal 

zone soils with very shallow water tables (average 

depth 0.6 ft) showed a nearly one-to-one fit and 

much better correlation (NcKee, 1978). 

Runoff 

Removal of the trees reduces evapotranspiration 

resulting in more water available for groundwater 

recharge and runoff. The magnitude of response is 

proportional to forest canopy reduction and solar 

radiation load (Hibbert, 1967). The totals from 

Table 1 show an increase of first-year yields of 1 

and 6 inch for the watersheds treated with minimum 

and maximum disturbance silviculture, respectively. 

However, the water yield increase from the maximum 

Table I. Actual and predicted annual runoff. 

Rain Con- Min Max 

Year fall trol disturb disturb 

Act Pred Biff Act Pred Diff -------------- inchiyear ----------------- 

1978 57 22 24 - 15 - 1979 54 4 6 5 1 10 4 6"&* 

1980 46 14 5 15 -l0A** 3 15 -12a"fc 

1981 36 0 0 0 0 1 0 1% 

1982 57 8 4 8 4 3 8 -5*A 

1983 65 18 14 21 -7"** 26 23 3 

1984 45 8 9 8 1 12 8 4k9: 

1985 51 7 3 8 -5a9~" 13 8 5n9: 

< 5 pet probability .I. 

,. .I- ,. < 1 pct probability J 11. 1. 

zc4*'* < 0.1 pct probability 

disturbance treatment was only significant. These 

yield increases fitted well with the responses of 

other watersheds in the eastern United States. 

Calculations with an equation based on degree of 

canopy removal and solar radiation (Douglass and 

Swank, 1975) resulted in 4 and 7 inch for the two 

treatments, respectively, Annual water yields for 

the post-treatment years continued to show more 

runoff from the highly disturbed watershed during 

normally wet years, as could be expected from the 

water table data, but the low disturbance watershed 

showed less runoff than predicted and expected from 

the water table levels. It is quite possible that 

both calibrations with the control watershed have 

shifted downward in response to forest maturation. 

Stormflow runoff before and after the treatments 

only showed a treatment effect of midsized storms 

on the maximum disturbance watershed (Swindel et 

al., 1983) partly because large storms were absent. 

The effect was probably due to complete vegetation 

removal, orientation of the windrows toward the 

drainage channel, and subsoil compaction by heavy 

machinery. Water table rises of about one inch have 

been measured when machinery passed nearby with the 

table 2-3 feet down (unpublished data, Riekerk). 

Water balances 

The data showed that evapotranspiration regulates 

the amount of water available for runoff and water 

table recharge. Evaluating evapotranspiration from 

the water balances of the leaky watersheds in the 

study area is difficult, but can be obtained from a 

lysimeter. The actual/potential evapotranspiration 

ratios from the lysimeter were applied to weather 

station data from the Bradford Forest. Calculated 

evapotranspiration was used in the water balances 

of the three watersheds (Figure 2). Residual values 

of the annual water balances represent seepage plus 

changes in storage, and contain all the measurement 

errors. The average seepage value of 1.4 inchlyear 

was very similar to that calculated by darcian flow 

through the underlying clay layer (Conover et al., 

1984; Pratt, 1979). Hawever, similar measurements 

for two small 10-acre watersheds in the same forest 

resulted in average seepage values of 13 inchlyear 

(Riekerk and Korhnak, 1984). This may be due to 

less runoff from the small watersheds without any 

ponds, and/or more gaps in the underlying clay. 
- RAlNFALL 

U EVAPOTRANSPIRATION 

- INCH RUNOFF 

GROUNDWATER 

Figure 2. Water balances of the Bradford Forest. 

CONCLUSIONS 

Flatwoods pine forest harvesting and regeneration 

increased water tables, runoff yield, and stormflow 

proportional to the degree of disturbance. 

The effects on water tables were more evident at 

deeper depths because of lower soil porosity. This 

created seasonal differences due to dry periods. 

Runoff water yield was increased by the maximum 

disturbance treatment during wet years, but the 

minimum disturbance treatment apparently reduced 

annual runoff as compared to the control. 

The stormflow of intermediate storms was increased 

possibly due to the orientation of windrows toward 

the drainage channel, and to subsoil compaction. 

A severe drought year during the study period 

showed a very slow recovery of hydrologic behavior. 

It required a whole and very wet year to recharge 

the system and bring runoff back to normal levels. 

Annual water balances that included calculated 

evapotranspiration showed little deep seepage in 

the large watersheds but ten times more from small 

watersheds without cypress ponds. 

The Bradford Forest watershed study was funded by 

the U.S. Forest Service, and the Austin Gary Forest 

lysimeter study was funded by the Florida Water 

Resources Center, Gainesville, FL. 

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forest practices in the Gulf coastal plain of 

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Forest Service, SE Exper. Sta., Asheville, NC, 

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Brown, S. A comparison of the structure, primary 

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Conover, C.S.; J.J. Geraghty; and G.G. Parker, Jr. 

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Pergamon Press, New York; 1967: 275-290 

Hewlett, J.D.; and R. Doss, Forests, floods, and 

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Hibbert, A.R. Forest treatment effects on water 

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watersheds; final report. Coord. Council Restor. 

Kissimee River Valley and Taylor Creek - Nubbins 

Slough Basin, Tallahassee, FL; 1982: 48 p. 

Langdon, O.G.; and K.B. Trousdell. Stand manipulation: Effects on soil moisture and tree growth in 

southern pine and pine-hardwood stands. In: Soil 

Moisture...Site Productivity, ed. W.A. Balmer, 

USDA Forest Service Southeastern Area, Atlanta; 

1978: 221-236 

Lorio, P.L., Jr.; and J.D. Hodges. Microrelief, 

soil water regime, and loblolly pine growth on a 

wet, mounded site. Soil Science Society of America, Proceedings 35; 1971: 795-800 

Lull, H.W. Ecological and silvicultural aspects. 

In: Handbook of Applied Hydrology, ed. V.T. Chow, 

McGraw-Hill, New York; 1964: 6.10-6.30 

McKee, W.H. Rust on iron rods indicates depth of 

soil moisture. In: Soil Moisture...Site Productivity, ed. W.A. Balmer, USDA Forest Service Southeastern Area, Atlanta; 1978: 286-291 

Ponce, S.L. The potential for water yield augmentation through forest and range management. Water 

Resources Bulletin 9; 1983: 351-419 

Pratt, D.A. The hydrogeology of a mixed pine and 

cypress commercial forest in Bradford county, FL. 

M.S. Thesis, University of Florida, Gainesville, 

FL; 1978: 103 p. 

Replogle, J.A.H.; H. Riekerk; and B.F. Swindel. 

Flow metering flumes monitor water in coastal 

watershed. Water and Sewage Works; 1978: 4 p. 

Riekerk, H.; and L.V. Korhnak. Environmental effect 

of silviculture in pine flatwoods. In: Third 

Biennial Southern Silvicultural Research Conference, ed. E. Shoulders, Forest Service, General 

Technical Report SO-54; 1984: 528-535 

Riekerk, H. Pine tree evapotranspiration. Water 

Resources Research Center, University of Florida, 

Gainesville, FL, Public. No, 62; 1982: 37 p. 

Rodriguez, H.M. Impact of intensive slash pine 

management on the hydrology 04 a coastal wet, 

savanna watershed, M.S. Thesis, University of 

Florida, Gainesville, FL; 1981: 97 p. 

Swindel, B.F.; and J.E. Douglass. Describing and 

testing nonlinear treatment effects in paired 

watershed experiments. Forest Science 30; 1984: 

305-313 

Swindel, B.F.; C.J. Lassiter; and H. Riekerk. Effects of clearcutting and site preparation on 

stormflow volumes of streams in Pinus elliottii 

flatwoods forests. Forest Ecology and Management 

5; 1983: 245-253 

Vickers, C.R. Effects of ditching on cypress pond 

herpetofauna in north Florida. M.S. Thesis, Univ. 

of Florida, Gainesville, FL; 1980: 48 p. 

White, E.H.; and W.L. Pritchett. Water table control and fertilization for pine production in the 

flatwoods. Institute of Food and Agricultural 

Sciences, University of Florida, Gainesville, FL, 

Bulletin 743; 1970: 41 p. 

Williams, T.M. Response of shallow water tables to 

rainfall. In: Soil Moisture. ..Site Productivity, 

ed. W.A. Balmer, USDA Forest Service Southeastern 

Area, Atlanta; 1978: 363-370 

Williams, T.M. Implications of hydrologic response 

to the practice of forestry on coastal forests. 

In: Florida's Water Resources - Implications for 

Forest Management, ed. W.H. Smith, School of 

Forest Resources and Conservation, University of 

Florida, Gainesville, FL; 1979: 92-102 

Williams, T.M.; and D.J. Lipscomb. Water table rise 

after cutting on coastal plain soils. Southern 

Journal of Applied Forestry 5; 1981: 46-48 

Woodruff, J.F.; and J.D. Hewlett. The hydrologic 

response of small basins in Georgia. Southern 

Geographer Vol. 11; 1971: 1-8 
STRIP CUTTING TO REGENERATE EROSION-CONTROL 

PLANTATIOI~S OF LOBLOLLY PINE;/ 

5. J. Urslc and P. D. LluffyZ/ 

Abstract,--A serious problem in the 

Coastal Plain is adequate regeneration of 

loblolly pine after harvest. The problem is 

especially acute where the pine was 

established to control erosion, Such 

plantations, largely on small private 

holdings, are now being harvested. Large 

acreages are reverting to hardiroods , and the 

sites are not suf f iciently improved for 

adequate growth of nos t desirable hardwood 

species. Four small catchments of loblolly 

pine in west Tennessee were strip-cut with 

natural pine regeneration, Adequate pine 

rsproduct ion and only slight, short-lived 

impairment of water quality derionr; tr::ted 

strip cutting as a practical solution, 

INTRODUCTION 

Public Law 92-500 was passed in 1972. Its goals 

were to maintain and improve the quality of the 

Nation's waters. It also directed the Scaces ro 

develop water-quali ty standards, Infomation on 

the quality of water flowing frm relatively 

undisturbed forest lands was meager, and such 

information was needed to assess changes due to 

forestry practices as well as to develop reasonable 

control strategies. These needs prompted new 

research on forested catchments in a number of 

Southern States. 

Coincident with these needs was deep concern over 

the loss of substantial acreages of pine to upland 

hardwoods, especially on nonindustrial private 

forests. Such forests now occupy two-thirds of the 

commercial forest land in both the Midsouth and 

Southeast. 

Over the last 10 years, 950,000 acres of 

nonindustrial private forests in the Southeastern 

States were harvested, either by clearcutting or 

high-grading, and kept in timber. Of these 950,000 

acres, 610,000 acres supported pine or oak-pine 

stands when harvested, and only 54 percent of the 

610,000 acres were successfully regenerated to pine 

or oak-pine (Knight 1985). 

Paper presented at Southern Silvicultural 

~esearch Conference, Atlanta, Georgia, November 

4-6, 1986. 

21 Principal Research Hydrologist and Soil 

~cTent ist , respectively , USDA Forest Service, 

Southern Forest Experinent Station, Yores t 

Hydrology Laboratory, Oxford, 14s 38655, 

In the Nidsouth, nonindustrial private owners now 

hold 78 percent of the upland hardwoou acreage, 

including an increase of 458,000 acres from 1977 to 

1985, The increase coincides with a decline in 

natural pine and oak-pine and is at least partially 

due to the selective harvest of pine and 

clearcut ting without adequate pine regeneration 

(Birdsey and McWilliams 1986). In addition, about 

7 million acres of pine plantation are held by 

nonindustrial private owners in the South and 

Southeast, a large portion of which were 

established on eroded and abandoned farmland. 

In terns of area, harvesting is the most 

important forestry activity. As such, it is of 

prinary interest to foresters and others concerned 

with both hydrologic changes, including water 

qualicy, and forest trends. During 1974-75, the 

Forest Hydrology Laboratory installed a study to 

evaluate the hydrologic effects of harvesting. 

Harvesting was completed in late 1974, and 

hydrologic recording was begun in May 1975. Strip 

cutting with natural regeneration was included to 

evaluate the potential of this practice for 

maintaining nonindustrial pine lands in pine. 

The loblolly pine ( Pinus taeda L.) plantations 

harvested were established on severely eroded, 

abandoned farmlands near Lexington in west 

Tennessee, The plantations on the Tennessee Valley 

Authoriv's Pine Tree Branch Watershed (PT) were 29 

years old when harvested; those on the nearby 

Natchez Trace State Forest (NT) were 37 years old. 

The soils are varying proportions of Lexington silt 

loan and Ruston sandy loam. 

Sixteen small catchments averaging 0.86 acre were 

instrunented and, in a balanced design with two 

replications at each of the two locations, the 

followirig four treatments were replicated: (1) 

undisturbed controls; (2) clearf elled and planted 
with pine; (3) clearfelled aild planted with pine, 

with disturbed areas fertilized and sown with rye 

grass; and (4) strip-cut on contour, Cut strips on 

the s trip-cut catchments averaged about one-chain 

(66 feet) in width. kave strips were about 

one-half chain wide and were left at the top, 

middle, and bottom contours of each catchment, 

Some trees in the leave strips were also harvested 

because of ice damage, The basal area of leave 

trees averaged about 38 ft2 per acre of watershed 

at both locations. Tfae number of leave trees per 

acre of watershed area averaged 91 in the 

29-year-old plantations arrd 44 in the 37-year-old 

plantations, 

Water-qwlity aspects for the clearcut catchments 

have been reported (tlcClurkin and others 1985), and 

complete hydrologic findings are in preparation. 

This paper deals primarily with the composition of 

pine reproduct ion and associated woody species on 

the strip-cut catchments, 

A regeneration survey of the four strip-cut 

catchments was made in September 1986, 12 years 

after harvest. Trees were tallied on 10 milacres 

on both sides of 10 one-chain transects located at 

r andorn azinut hs and distances from the appr oxinate 

center of each catchment. Tnus, 200 milacres were 

sanpled on each of four areas for a total of 800 

nilacres or about 25 percent of the total area 

sampled, Trees on leave and cut strips were 

tallied separately, The transects selected were 

approximately proportional to the areas of 

concentric circles to avoid clustering near the 

center of the catchment. 

Pine reproduction was tallied as seedlings (all 

stems less than 1.45 inches in diameter at breast 

height) and by larger 1-inch classes, Hardwoods in 

the l-inch diameter class (0.50 to 1.45 inches in 

diameter breast height) and larger were tallied by 

1-inch classes by species, For purposes of some 

comparisons, pine seedlings 6 feet and over in 

heighc were assigned to the I-inch dianeter class. 

Saplings are trees in the 2-inch diameter class and 

larger 

Katural Regeneration 

Twelve years after hamesting, pine regeneration 

averaged 835 stens per acre, 566 seedlings and 264 

sapling size and Larger, Xn addition, there were 

I26 yellow poplar iliriodendron tulipifera E,) per 

acre; 75 of these were sapling size and larger, 

Thus, rc,,i.neratlur, of desirable s~ecies averaged 

961 ster,'s per acre, of which 344 wcrc saplings and 

larger (t,iSle 1). lVnost all. the yellow poplar 

&:ere thrifty single steins of seed origin, 

Table I,--Natural regeneration on strip-cut 

catchraents I2 years a£ ter harvest--average 

of four catchnents 

Stems per acre 

Pine Poplar Tot3 

Seed li ng s 566 5 1 617 

Saplings 

Tot a1 

Seedlings ( 1-inch 17 1 5 1 2 2 2 

d.b.h. class) 

Saplings 

Tot a1 

Considering only pine seedlings and saplings (835 

treeslacre), the area sampled is 100 percent 

stocked by survey definitions (600 seedlings/acre). 

Gonsiderit~ trees in the 1-inch diameter class 

and larger, there were 440 pine and 126 yellow 

poplar for a total of 566 desirable sterns per acre 

(table 1). This compares with the average survival 

of seedlings planted on the eight clearcut 

catchments, 66 percent or 587 trees per acre at age 

6. 

Pine regeneration and milacre stocking between 

locations was inconsistent. One less successful 

catchment at each location was included with the 

two having the best results. However, average 

results for the two locations were quite similar 

(table 2). 

Table 2.--Natural regeneration on strip-cut 

catchments 12 years after harvest 

Stems per acre 

Pine Poplar Total 

Pine Tree 

Seedlings 49 5 5 5 550 

Saplings 215 9 8 313 

Tot al 71 0 153 863 

Iqatchez Trace 

Seed li ngs 6 38 48 686 

Saplings 322 5 2 37 4 

Tot a1 960 100 1,060 

-- Stocking 

&era1 I., mil,*n:re s tcjcliing averaged 44 percent for 

pine, 10 percent for yellow poplar, and 44 percent 

of the nilacres were stocked with either pine or 

poplar (table 3). 
Table 3 --Stocking of natural regeneration 

on strip-cut catchments 12 years af ter 

harvest 

Stocking percent 

Pine or 

Pine Poplar poplar 

Seedlims and sa~lims 

Pine Tree 4 0 11 4 6 

Natchez Trace 48 9 52 

Ave rage 4 4 10 49 

Trees 1-inch and larger 

Pine Tree 26 11 32 

Natchez Trace 33 9 38 

Ave rage 29 10 3 5 

Saplings 

Pine Tree 18 6 23 

Natchez Trace 2 4 5 27 

Ave rage 2 1 6 25 

Stocking of either pine or poplar in the 1-inch 

or larger diameter class averaged 35 percent, and 

trees of sapling size and larger averaged 25 

percent, Thus, milacre stocking was equally 

divided between seedlings and those of sapling size 

and larger. 

Sixty-two percent of the milacre plots were in 

the cut-s trip areas and 38 percent in the leave 

areas. As expected, regeneration of pine and 

poplar in the cut strips was better, but milacre 

stocking in the leave strips averaged 40 percent, 

including some advanced regeneration ( table 4). 

Table 4 .--Stocking of natural regeneration on cut 

and leave strips 12 years after harvest 

Stocking percent 

Pine or 

Pine Poplar poplar 

Cut Leave Cut Leave Cut Leave 

Pine Tree 38 40 15 3 48 41 

Natchez Trace 56 36 8 10 62 39 

Average 47 38 11 6 55 40 

Regeneration surveys made 3 years after harvest 

(1977) on two of the four strip-cut catchments 

indicate that there was not enough seed-in-place to 

provide adequate pine regeneration (table 5). 

However, pine regeneration more than tripled, and 

milacre stocking increased about 2.5 times between 

1977 and 1986. 

Since the two catchments sampled had the best 

regeneration in 1986, the average value for all 

four catchments in the initial sampling was 

probably less. Thus, even though a survey 3 years 

after harvesting forecasted poor results or partial 

failure, the areas were well stocked by 1986. 

Table 5. --Natural regenerat ion of pine 3 and 

12 years after harvest on two catchments 

Year ~rees/acre Stocking percentl/ 

PT7 NT8 Means PT7 NT8 Means 

- l/~ased on 100 milacre plots in 1977; 200 in 

19 86. 

Pine seedlings were distributed among all age 

classes and ranged up to 15 feet tall, while 

saplings ranged from 2 to 7 inches in diameter, 

including some advanced regeneration in the leave 

strips (table 6). This distribution suggests that 

regeneration was partially dependent on crown 

development of the leave trees and an increase of 

seed production. The results indicate that the 

leave strips can be narrow--just wide enough for 

harvesting the leave trees without disturbing the 

regenerated areas. Periodic observations can 

determine when to harvest the leave strips. And, 

if desired, the stands can be improved with very 

minimum single-tree release. 

Table 6. --Distribution of pine regeneration on 

s trip-cut catchments 12 years af ter harvest 

- Seedlings Saplings 

Number Diameter Number 

Height per acre class per acre 

Feet Inches 

lot 53 5+ - 3 3 

Tot a1 566 26 9 

Hardwoods 

Overall, 26 percent of the hardwoods other than 

yellow poplar were maple (Acer sp,), largely with 

mlilt iple sprouts. Dogwoods (Cornus florida L.) 

accounted for 12 percent of the hardwoods, 

suggesting improvement of the site, and blackjack 

oak (Quercus marilandica Muench. ) 11 percent. No 

other species comprised more than 6 percent of the 

hardwoods, 

Hardwoods other than poplar averaged 1 ,b14 s tc:is 

per acre, of which 1,162 or 72 percent were in the 

1-inch diameter class (table 7). Another 21 

percent were in the 2-inch diameter class. There 

were 452 sapling hardwoods per acre, compared to 

344 pine and yellow poplar saplings. 
Table 7.--Hardwoods on strip-cut catchments 

12 years after harvest (minus yellow poplar) 

Stems/acre Percent in 

seedlings 

Pine Tree 

Seedlings 1,330 74 

saplings 48 0 

Tot dl 1,810 

Natchez Trace 

Seedlings 992 7 0 

Saplings 425 

Tot dl 1,417 

Average 

Seedlings 1162 7 2 

Saplings 452 

Tot a1 1,614 

Other hardwoods greatly outnumbered pine and 

poplar in the 1-inch diameter class and were about 

twice as numerous in the 2-inch class (table 8). 

However, there were more pine and poplar ( 169 

treeslacre) than other hardwoods (118 treeslacre) 

in the 3-inch and larger diameter classes. 

Table 8.--Pine, yellow poplar, and other hardwoods 

on strip-cut catchments 12 years after harvest 

Diameter Loblolly Yellow Other 

class pine poplar hardwoods 

Inches --Number of trees per acre-- 

Water Qualicy 

Sedinent is the most important constituent 

affecting water quality in the southern pinery. 

Sediment concentrations for the s trip-cut 

catchments averaged about 350 mg/l during part of 

1975 and 1976 (20 months), but decreased to or 

below the suggested base rate for undisturbed pine 

of 60 mg/l during each of the next 5 years and 

averaged 35 mg/l during this period. Soil export 

from ihe strip-cut catchments during the initial 20 

nonths averaged about 300 pounds per acre compared 

to about 50 pounds per acre from the control 

catchnents. These values contrast sharply with 

averaged firs t-year sediment concentrations of 

2,700 mg/l and soil loss of 5.9 tons per acre 

following three methods of mechanical site 

preparation on similar sites (Beasley 1979). 

Average sediment concentrations for the s trip-cu t 

catchments were lower than those for the catchments 

in the two clearcut treatments, but differences 

were slight and concentrations within treatments 

varied as much as between treatments, primarily due 

to characteristics of the gully channels. 

Skidding on contour and not disturbing the 

channels, we feel, contributed to these low 

concentrations. Restoration of cover on the cut 

strips should minimize any increases in sediment 

loss when trees in the leave strips are harvested. 

DISCUSSION 

We are aware of one other tested, low-cost 

alternative to naturally regenerate erosion control 

plantations that minimized soil disturbance and 

protected water quality. Van tear and others 

(1985) working in the Piedmont obtained adequate 

loblolly regeneration from seed-in-place after 

several prescribed burns to control hardwoods 

be£ ore clearf elling. Burning did not significantly 

affect chemical water quality, and increases in 

sediment concentrations and sediment export were 

minimal and short-lived. 

Results obtained with strip cutting in this study 

suggest that seed-in-place on severely eroded areas 

may be inadequate. Too, burning eroded areas 

having gully channels in the hilly Coastal Plain 

has been shown to temporarily impair water quality 

(Ursic 1986). 

Strip cutting may be less satisfactory on better 

sites due to the potential for increased hardwood 

competition but appears suitable for regenerating 

erosion-control plantations af ter the first 

rotation and is worthy of further trials. Strip 

cutting may also be less satisfactory where yellow 

poplar does not make a contribution. Consideration 

of these factors can help determine which method to 

use to perpetuate a pine type. 

ACKNOWLEDGMENTS 

The cooperation and subs tant ial assistance 

provided by the State Forester of Tennessee, 

Division of Forestry, Tennessee Department of 

Conservation, Nashville, TN, and the Director of 

the Division of Forestry, Fisheries and Wildlife 

Development, Tennessee Valley Authority, Norris, 

TN, are gratefully acknowledged. 

LITERATURE GI TED 

Beasley , R.S. Intensive site preparation and 

sediment losses on steep watersheds in the Gulf 

Coastal Plain. Soil Science Society of America 

Journal. 43:412-417; 1979. 

Birdsey , Richard A. ; McWilliams, William H. 

rlidsouth forest area trends. Kesour. Bull, 

SO-107. New Grleans, LA: U.S, Deparicirzitt of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1986. 17 p. 
Kn!ght, Herbert A. Recent survey findings and 

growth rates in the Southeast. In: Cubbage, 

Frederick W., ed . Trends in growing and marketing 

southern timber. Proceedings, 1985 southern 

forest economics workshop ; 1985 Plareh 13-1 5; 

Athens, GA. Asheville, NC: U.S. Department of 

Agriculture, Forest Service, Southeastern Forest 

Experiment Station; 1985: 44-52. 

McClurkin , D.C , ; Duf fy , P . D, ; Urs ic , S. J. [and 

otherc], Water quality effects of clearcutting 

upper Coastal Plain loblolly pine plantations, 

Journal of Enviromental Quality. 14(3) :329-332; 

1985. 

IJrsic, S. J. Sediment and forestry practices in the 

South, In: Proceedings, fourth federal 

interagency sedimentation conference; 1986 March 

24-27; Las Vegas, NV, New Orleans, LA: U.S. 

Ikpart~~lent of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1986: 28-37, 

Van kar, D.H. ; Douglass, J.E. ; Cox, S.K. [and 

others]. Sediment and nutrient export in runoff 

from burned and harvested pine watersheds in the 

South Carolina Piedmont, Journal of Environmental 

Quality. 14(2) : 169-174; 1985. 
POTENTIAL ALLELOPATliIC INTERACTIONS OF Sapium sebiferum 

ON LOBLOLLY PINE SEED GEPJIINATION AND SEEDLING GROL~II~! 

2 1 C. A. GreshamAbstract.--Allelopathy, the deleterious interaction of two plants via the release of a chemical into 

the soil or air, has only recently been considered in 

forestry, There are many examples of reduced seed 

germination and growth reduction due to phytotoxins for 

many forest species, but few for loblolly pine. A few 

published reports indicate that several herbaceous and 

woody species affect loblolly pine. To confirm an 

allelopathic interaction one should consistently notice 

the effect and the presence of the suspected species, 

eliminate competition for light, water, and nutrients 

and conduct greenhouse experiments with leachates in 

artificial potting media and with forest soil. This 

procedure is being used to investigate the interaction 

of tallowtree leachates and the germination of loblolly 

pine seed and seedling growth. 

INTRODUCTION 

Allelopathy has been defined as "any direct 

or indirect harmful effect by one plant (including 

microorganisms) on another through the production 

of chemical compounds that escape into the 

environment" (Rice 1974). The important point in 

this definition is the production of a compound 

that is released into the environment. Another 

interaction between two plants is competition, but 

allelopathy is not a factor of competition, because 

a competitive interaction involves the withdrawal 

of some factor from the environment. The term 

"interference" has been suggested (Muller 1969 in 

Rice 1974) to include both allelopathy and competition. 

PRODUCTION AND RELEASE OF ALLELOPATHIC COMPOUNDS 

Allelopathic chemicals are most commonly 

reported to be produced in the leaves, stems and 

roots of woody and herbaceous species (DeBell 

1970, Rice 1974). Leaves are considered to be the 

most consistent source and roots are found to be 

sources to a much lesser extent. Rice (1974) re- 

~orts that flowers and fruits have not been widely 

assayed for allelopathic chemicals and that the 

research done on seeds has not revealed many 

toxins. These results reflect the difficulty of 

1' Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

21 Associate Professor, 3aruch Forest Science 

~nstitute, Clemson University, Georgetown, SC 

29442. 

'teasing out' separate plant parts as the source 

of the toxin. This same difficulty is present 

when trying to determine the pathway in which the 

chemicals enter the environment. 

HOW DO TOXINS ENTER THE ENVIRONT*fENT? 

Four mechanisms are commonly listed for allelopathic chemicals to enter the environment. The 

first is volatilization, the direct release of the 

chemical into the air. The chemical can therefore 

be produced from either the leaves or stems to be 

released into the air. This mechanism is probably 

not of importance to southern pine forestry since 

it is associated with arid regions (Rice 1974). 

The most commonly researched mechanism is the 

rainwater leaching of leaves and stems. Most 

allelopathic studies involve the application of 

cold water leachates of leaf and stem material to 

seeds or seedlings of the test species. DeBell 

(1971) concluded that this was the mechanism by 

which salicytic acid entered the soil under cherrybark oak (Quercus falcata var pagodifolia Ell .). 

Exudation from roots is another mechanism by 

which toxins can enter the environment. However, 

this pathway is difficult to isolate from the release of chemicals resulting from root death and 

the decay of roots by soil microorganisms. Rice 

(1974) reports that root exudation has been documented for several species. 

Many chemicals are released upon the death of 

plant material and this constitutes another pathway for the release of toxic chemicals. Separating 

those chemicals released from the death of a plant 

and chemicals produced by microorganisms is not 
easy, thus the isolation of this pathway is 

difficult. Also soil microorganisms could convert 

a non-toxic coxlpound released from plant tissue 

into a toxic one, thus producing the appearance of 

the plant tissue releasing the toxic chemical. 

.?s the allelopathic research concerning loblolly pine is discussed, one will notice that more 

than one of the mechanisms is functioning, as is 

most probably the case in nature. From a practical 

standpoint the mechanism responsible for the toxin 

entering the environment is not what should concern foresters, Sut rather the effect of the toxins on 

the germination of crop tree seed and the survival and early growth of desirable seedlings. 

ALLELOPATHY AND SOUTHERV PINE FORESTRY 

One of the first papers calling foresters' 

attention to the potential importance of allelo- 

~athy in forest management was DeBell 1970. He 

reviewed the nature of phytotoxins, the mechanisms 

by which the toxins enter the environment and 

environmental effects on phytotoxins. He then 

summarized examples of phytotoxic activity of 

woody plants and concluded that the research to 

date was inadequate to warrant the forest manager 

considering phytotoxins in the management of forests 

and forest soils. Ten years later, R. F. Fisher 

(1980) published a similar review article in the 

Journal of Forestry in which he discussed allelopthy as a potential cause of pine regeneration 

failure. In the article he tabulated trees, 

shrubs and herbs that produce phytotoxins that 

affect forest trees, and listed the class of the 

active chemical. He concluded that allelopathy is a selective interaction between certain species 

under certain conditions, and it should not be 

blamed for any mysterious regeneration failure. 

Rather, allelopathy should be considered equally 

with other possible causes. 

-4 great deal of research has been conducted 

by botanists and ecologists on allelopathic interactions of tree, shrub and herbaceous species as 

is evident from the two reviews by E. L. Rice 

(Rice 1974, 1979). The silviculture and management of loblolly pine has been the focus of untold 

numbers of studies in the Southeast over the past 

fifty years (see Wahlenburg 1960 for the "earlyn 

literature). Despite these facts there is an amazing lack of research published on allelopathic 

effects of forest shrubs and herbs on loblolly 

pine regeneration and early growth. Two explanations are possible. First is that allelopathy 

is not important in regenerating loblolly pine, 

and the second is that it is important but has not 

been given adequate research attention. The following discussion will indicate that there is 

potential for an allelopathic reduction in germination and early growth, and hence the latter 

explanation is supported. 

ALLELOPATHY hYD LOBLOLLY PINE 

One of the first allelopathy studies involving loblolly pine v7as that of Hollis et a1 (1982) 

which screened leachates from nine herbaceous and 

woody species common to the coastal plain. Leachates from six of the nine species interfered with 

germination and/or radicle elongation of loblolly 

and slash pine. They then applied mulches to 6 

week old seedlings and noted that the mulch of 

Euoatorium caDil?ifolium stimulated seedline ., growth while a mulch of Lyonia lucida decreased 

growth. They also reported that seedlings planted 

within 0.5 m of -- Lyonia lucida debris here smaller 

than those farther away. 

Piheeler and Young (1979) demonstrated that 

leachates from pots giowing Festuca arundinacea 

reduced the growth of potted loblolly pine seedlings. Likewise, Gilmore (1980) reported that the 

presence of Setaria faberii seedlings in the same pot reduced wwofotted loblolly pine 

seedlings. Also leachates from pots growing 

-- Setaria faberii reduced the growth of potted loblolly pine seedlings, In a later study, Gilmore 

(1985) demonstrated that water extracts of Setaria 

faberii inhibited the germination and radicle 

elongation of loblolly pine seed. Sold water extracts of Andropogon viEginicus shoots were shown 

to reduce the stem, root and needle lengths of 

loblolly pine seedlings (Priester and Pennington 

1978) . 

?ROCEDURE TO IDENTIFY ALLELOPATHIC SPECIES 

The previous section indicates that few 

species have been identified as having an allelopathic relation to loblolly pine, and it is quite 

possible that others exist. But how does one test 

or confirm this relation? From the published 

results and personal experience, 1,submit that 

there are three sequential steps that must be 

taken to identify an allelopathic relation. 

First there must be a consistent association 

between the suspected allelopathic species and 

reduced seed germination and/or seedling growth. 

Greenhouse research fGilmore 19851 has shown that 

soil texture affects the severity of the allelopathic suppression but the effect is consistently 

measurable. In the field this step only confirms 

that a competitive or allelopathic relation exists, 

but does not differentiate between the two. 

Once a consistent association has been 

established, the competition factors must be 

eliminated. This involves either observational 

or manipulative data (greenhouse experiments) to 

demonstrate that the reduction of germination and/ or growth is not due to light availability, water 

stress or insufficient mineral nutrients. 

Finally, greenhouse experiments similar to the 

ones reviewed above need to be conducted. Standard 

methods include preparing a cold water extract of 

leaves and stems of the suspected species, and 

applying the leachate to seeds in a petri dish 

and applying the leachate to seedlings growing in an art if icial media. 

If this pair of experiments indicate a germination retardation or a seedling growth reduc- 
tion, then the seedling experiments should be 

repeated with seedlings growing in forest soil. 

Tinnin and Kirkpatrick (1985) reported that three 

broadleaf species reduced root growth of 

Pseudotsug menziesii and two of - these also reduced 

shoot growth, in an artificial soil mix. However, 

no consistent expression of allelopathy was 

observed when field soil was used. 

Gilmore (1985) identified eight compounds in 

leaf leachates of Setaria spg and-demons'trated 

that leaf leachates reduced germination of loblolly pine seed and inhibited radicle elongation. 

He could not find one of the eight compounds in 

field soil below a leaf mulch that had been 

missed periodically. From this, he concluded 

that Setaria phytotoxins are rapidly converted to 

nontoxic substance(s) in the soil. 

CONCLUSIONS 

Allelopathy can be thought of as chemical 

warfare among plants and it differs from competition in that a compound is being introduced 

into the environment, whereas cornpetition is the 

removal of compounds or energy from the environment. 

The production of phytotoxins has been long 

studied by ecologists and botanists, but its role 

in southern pine forestry has not been widely 

researched. The few published studies involving 

loblolly pine indicate that there are several 

herbaceous and woody species that could reduce 

the gemination of loblolly pine seed andlor 

reduce seedling growth. Therefore, these species 

could hinder natural regeneration of loblolly by 

a seedtree or shelterwood method. 

LITEfLamRE CITED 

APPLICATION OF THE PROCEDURE: A CASE STUDY 

Three patches of an otherwise homogeneous 

loblolly pine shelterwood stand in coastal South 

Carolina do not have the sapling regeneration 

that is present throughout the stand. gut these 

patches do contain many stems of chinese tallowtree Sapium sebiferum. This observation fulfills 

the first step of identify in^ a consistent relation. Since the stand regenerated over 20 years 

ago, eliminating the competition factors is impossible. Today all that can be said is that the 

soil and topography of the patches is not different from the rest of the stand, so there are no 

site differences causing patches of regeneration 

failure. 

Greenhouse experiments have been conducted 

with cold water leaf leachates of the tallowtree 

in artificial media and a significant reduction 

of loblolly pine germination and seedling growth 

was observed. These experiments are being repeated with soil from the shelterwood stand as a 

growth media. Thus the final step of confirming 

an allelopathic interaction is being taken in 

this study. If the leachates do not reduce germination and growth of loblolly pine, this study 

will demonstrate the neutralizing effect of a 

forest soil as in the studies of Gilmore (1985) 

and Tinnin and Kirkpatrick (1985). If the leachates do reduce germination and seedling growth, 

this presents a strong case for an allelopathic 

interaction. 

This three step procedure that yields circumstantial evidence without any direct data to 

indicate an allelopathic relation in the field. 

the could argue that the leachate solutions are 

more concentrated than would be found in nature 

because leaf material was allowed to soak for a 

period of time, and the forest floor would not 

flood in a drained forest soil. Any forester with 

experience in the lower coastal plain, where 

tallowtree is most commonly found, knows that many 

areas have groundwater at or above the groundline 

during the winter. Thus the soaking treatment is 

not that artificial. 

DeBell, D. S. New problems in forestry. Journal 

of Forestry 68:335-337. 1970. 

DeBell, D. S. Phytotoxic effects of cherrybark 

oak. Forest Science 17:180-185. 1971. 

Fisher, R. F. Allelopathy; a potential cause of 

regeneration failure. Journal of Forestry 

78:346-350. 1983. 

Gilmore, A. R. Phytotoxic effects of giant foxtail on loblolly pine seedlings. Comparative 

Physiol. and Ecology 5:183-192. 1980. 

Gilmore, A. R. Allelopathic effects of giant 

foxtail on germination and redicle elongation 

of loblolly pine seed. 2ournal of Chemical 

Ecology 11:583-592. 1985. 

Hollis, C. A., J. E. Smith and R. F. Fisher. 

P.llelopathic effects of common understory 

species on germination and growth of southern 

pines. Forest Science 28:509-515. 1982. 

Iluller, C. H. Allelopathy as a factor in ecological process. S'egetatio, Haag. 18:348-357. 

1969. 

Priester, I). S. and M. T. Pennington. Inhibitory 

effects of broomsedge extracts on the growth of 

young pine seedlings. USDA Forest Service. 

Res. Paper SE-182. 1978. 

Rice, E. L. Allelo~athy. ?Jew York: Academic 

Press; 1974. Z53pp. 

Rice, E. L. Alle1opatF.- - an update. Botanical 

Review. 45: :5-109. 1979. 

Tinnin, R. 0. and L. A. Kirkpatrick. The allelopathic influence of broadleaf trees and shrubs 

on seedlings of Douglas-fir. Forest Science. 

21:945-956. 1985. 

Iqahlenburg, I?. G. Loblolly Pine. Durham, N.C.; 

School of Forestry. Duke University. 1960. 603pp. 
;v%eeler, G. L. and J. F. Young. The allelopathic 

effect of fescue on loblolly pine seedling 

growth. Ark. Rgr. Expt. Sta. Arkansas Farm 

Research 28: 6. 1979. 
EFFECTS OF SILVICULTURAL PRACTICES IN BOTTmLAND 

1 / KARflWOODS ON SWMP RABBIT HABITAT2 / G. A, Hurst and M. W. SmithAbstract.--Forage and cover for the swamp 

rabbit were sampled 5 times from August 1980 

through August 1981 on. 4 mature bottomland 

hardwood forests (age 55-69 years) in Oktibbeha 

County, and on a recently clearcut bottomland 

site in Noxubee County, Mississippi. Three of 

the forests received improvement cuts 8 to 9 

years prior to vegetative sampling. The fourth 

forest was not cut. Total forage from grasses, 

sedges, forbs and vines in August was significantly greater (P < 0.01) on the clearcut (831 

kg/ha) than on the thinned forests (160 kg/ha) 

and the uncut forest (84 kg/ha) . Forage in 

February was significantly greater (P < 0.01) 

on the clearcut (116 kglha) than on the uncut 

forest (14 kg/ha) and the thinned forest (17 

kg/ha) with the highest basal area. The other 

thinned forests had 32 and 73 kg/ha in 

February. Vegetative cover (lateral screening 

cover) was always significantly greater 

(P < 0.01) on the clearcut than on the forests. 

Thinned forests generally had more cover than 

the unthinned forest. 

Swamp rabbit aqua ticus) habitat 

consists of swamps, marshes, and bottomland hardwood forests' (Bruna 1965, Chapman and Feldhamer 

1981, Allen 1985)- Many bottomland hardwood 

forests in the South, particularly in the lower 

Mississippi Valley, have been cleared for intensive agricultural use (S ternitzke 1965, Harris 

1984). Since 1939, over 2.67 million ha of bottomland hardwood forest along the Mississippi 

River have been converted to agricultural use 

(USDI 1978). 

About 8.1 million ha of bottomland hardwood 

forests remain on river system in the South 

(Hodges and Switzer 1979). Garner (1969) and 

Mullin (1982) stated that sgvicullzeard practices 

in bottomland hardwood forests improved =amp 

rabbit habitat. This study was conducted to 

1' Paper presented at Southern silvicul rural 

Research Conference, Atlanta, Georgia, November 

4-6, $786. 

- Professor and Graduate Research Assistant, respectively, Dewrtment of Wildlife and 

Fish, Miss. State Univ., .Miss. State, MS 39762. 

quantify the effects of certain silvicultural 

practices on swamp rabbit forage and cover on 

selected river systems, 

METHODS 

Five study areas in the Interior Flatwoods soil resource area (Pettry 1977) of 

east-central Mississippi were used. Areas 1-4 

were mature bottomland hardwood forests in 

Oktibbeha County, and area 5, located in 

Noxubee County, was a recently clearcut 

bottomland hardwood site (Smith 1982). 

Area 1 (140 ha) was adj.acent to Cypress 

Creek on Noxubee National Wildlife Refuge 

(NNWR) and had been cutover in the early 

1930's, but had not received any further 

treatment until 1972-73. At that time, at age 

60 years, an improvement cut removed 113 of 

the volyme and reduced the basal area from 24 

to 16 m /ha. 

Area 2 (89 ha) was also located on NNWR, 

between Cypress Creek and Oktoc Creek. The 

forest had been cut-over around 1933 and has 

not received any silvicultural trgatment since 

purchase by NNMR in 1940. 
Area 3 (10 ha) and area 4 (32 ha) were adjacent, located on Cypress Creek on the John 

Starr Memorial Forest of Mississippi State University. Both tracts were cut 3 times in the 

l96Ots, and once in 1971. These fre uent cut- 9 tings maintain9 basal areas of 13 m /ha on 

area 3 and 26 m /ha on area 4. 

Area 5 (40 ha) was adjacent to Sun Creek, 

about 19 Km west of Macon. Area 5 was a mature 

bottomland hardwood forest before clearcut ting 

in 1980. All unmerchantable trees were cut and 

left on the ground, but no further site preparation was performed. Loblolly pine (Pinus 

- taeda) seedlings were hand-ylanted in December 

1980. 

Common overstory and understory species in 

areas 1-4 were red maple (Acer rubrum), common 

pawpaw (Asimina triloba), American hornbean 

(Carpinus carolinian?), hickory (Carya spp.), 

American beech (Fags grandifolia) , green ash 

(Fraxinus ~e~~ns~~~vw.~a.c~) , sc~e tgum (Liquidambar 

styraciflua), blackgum (Nyssa sylvatica), overCUD oak (Ouercus 

.L-- lvrata). swamp chestnut oak "- - .e ,, (9: rnichauxii), water oak (L kigra), cherrybark oak (Q. pa_go_da), willow oak (Q, ghellos), 

and winged elm (Ulmus alata) . Common groundstory plants included Virginia snakeroot (~ristbloch+ .serpentaria), 

e 1 e p ha n t ' s f o o t , (El-e~_h.an-t-o F?_S car 01 in &aqls) , narrow-leaved water willow (Justicia lanceolata), cut-leaved water hoarhound (Lycopus 

americanus) , partridgeberry (Mi tchella reyens), 

lizard's tail (i_u~r_r!s- $-e~~~ur~), giant cane 

(Arundinaria gigantea), white grass- (Leersia 

virginica) , barbed panic-grass (Pani.um microcarpon), small-fruited panic-grass (!. polyanthes), spikegrass (Un-iqla sc-~~s-il~flo_r_a), thlcket sedge (La-~QX abscondita) , thin-f ruit sedge 

(C. f laccosp~~a-) , woodland sedge (C. hya_l.in.e 

lepsis) , bladder sedge (g. intumescens) , blunt 

br om s ed ge (2, ~r-ibu_I,o iLe2) , cr os sv ine (Ani_s-ol 

s tichus capreola ta) , Roykin clusterpea (Dioclea 

multif lora) , Japanese. honeysuckle (Lo~icera 

japonica) , Virginia creeper (_Parthenocissus 

quinque f olia) , poi son ivy (?&us ~ad?,cans), and 

greenbriar (Smi1ax;spp.) . Common plants on the clearcut (area 5) included bush aster (A-sxr dumosus), f ire-weed 

(Erechti tes hieracifolia):, horse-weed (Er igeron 

canadensis), goldenrod (Sol idago spp. ) , broomsedge bluestem (Andropogon virginicus) , beaked 

panic-grass (Panicurn ancep.), forked panic-grass (It. dichotomum) , thicket sedge, 

bladder sedge, marsh cyperuE (Cyperus* pseudovegetus) , crossvine, Japanese honeysuckle, 

climbing hempweed (Mikania scandens), and 

Virginia creeper. 

A point-sa pling method with a basal area 5' factor of 2.3 m /ha, has used to estinlate stand 

conditions in areas 3 acd 4 in July 1980 and in 

areas 1 and 2 in May 1981. At each sample 

point, all pr ism-recorded trees with a diameter 

at breast height of 15.2 an or greater were 

tallied. S cies, diameter, and merchantable 3 pulpwood (m ) or number of 4.88 m logs of 

sawtimber were recorded for each tree (Table 

1) 

Permanently marked sampling lines were established in each area. The lines wen: 100 m 

apart and perpendicular to creeks. Number and 

length of lines were-a hcCion of area size: 

Area 1 had 13 lineis 342. to 1,187 m long, Area 2 

had 4 lines 865 to 946 .m in length, Areas 3 and 

4 each had 6 lines 201 m long, and area 5 had 4 

lines 342 m long. 

Vegetative sampling plots were randomly 

located 20 to 282 m apart along the lines. 

Forage abundance was sampled by a ranked-set 

method (Halls and Dell 1965) in August and 

November 1980, and in February, May, and August 

1981. At each sampling plyt, 3 circular hoops 

107 cm in diameter (0.89 m ) were dropped at 

arm's length, 1 directly in front of the observer, 1 to the immediate right, and 1 to the 

immediate left of the .observer. Rankings of 

high, medium, or low sere assigned to the hoops 

according to an occular estimate of the amount 

of herbaceous forage in each hoop. At the first 

sample point, the hoop ~ith the high amount of 

vegetation was sampled, At the second plot, the 

hoop with the medium amount was sampled, and the 

hoop with the low amount was sampled at the 

third plot. High, medium, and low plots were 

sampled in succession and equal numbers of each 

were taken. The number of sample plots was 

determined by Stein's two-stage test (Steel and 

Torrie 1960.) 

Various grasses, sedges, forbs, and vines 

are the important focxl plants of swamp rabbits 

in the South (Richardson 1963, Sullivan 1966, 

Garner 1969, Smith 1.982). Therefore, green, 

succulent, new-growth parts of those plant 

groups were hand-picked or clipped to a height 

of 1.8 m above ground.. Rabbits cannot reach 

this high, but rabbits do cut the entire plant 

down by clipping at the base so that all of the 

plant is available. Forage was separated to 

species, placed in paper bags and dried in a 

forced-draft oven at 40°C .for a minimtnn of 72 

hours and weighed . A density board (cover board) 15.2 cm wide, 

1.83 m tall, and graduated in 30.5 cm intervals 

was used to rate vegetation considered to be 

rabbit cover. Cover was rated at the same plots 

used for sampling forage. At each plot cover 

rating was made with the board placed 20.1 m 

from the plot center in each of the 4 cardinal 

compass points. The observer knelt at plot 

center, positioned his head 30 cm above ground 

level, and rated visual:obstruc tion of each 

graduated interval on the board by living or 

dead vegetation. A rating of zero was used to 

designate that none of that interval could be 

seen (totally obstructed) and 10 designated that 

all the board interval could be seen. Cover 

ratings of the 6 intervals were averaged for 

analysis. 

The RUNMACE I1 Analysis of Variance Program 

(Scott et al. 1981) was used to analyze rabbit 

forage abundance and cover. The Least Significant Difference technique (Carmer and 

Swanson 1971) was used to test for differences 

among means. All tests were performcd at the 

P = 0.01 level. 
RESULTS (clearcut), significantly so in 4 of 5 samples. 

Area 1, improvement cut in 1972-73 (8 years 

The greatest amount of forage occurred in prior to sampling forage), consistently 

August, followed by May and November. The least had the second highest amount of forage. 

amount occurred in February (Table 2.) Total Area 1 had significantly more total forage 

rabbit forage was most abundant on area 5 in 4 of' 5 samples when compared to area 2, 

Table 1 .--Stand characteristics for 4 bottomland hardwood forests, Oktibbeha 

County, Hississippi, 1 980-81a. 

2 Age Basal- area (m /ha) 3b Volume (m /ha) ---. No. treeslha 

Area (years) sawtimber pulpwood sawtimber pulpwood sawtimber pulpwood 

z~ata includes all stems with dbh of 15.2 on and greater. 

Volume is merchantable amount. 

Table 2.--Swamp rabbit forage, oven-dry weight (kg/ha) by plant group, on 4 

mature bottomland hardwood forests and a clearcut, Oktibbeha and Noxubee 

Counties, Mississippi, 1980-81. 

Plant Area 

Date group 1 2 3 4 5 - ..-. - - -.- . -- -.- -A**-- -- 

Aug. 80 sedgea 22 A 7 A 8 A 19 A 134 B 

grass 43 A 10 A 6 A 42 A 222 B 

vine 109 A 56 A 108 A 89 A 62 A 

forb 24 A 10 A 10 A 9 A 274 B 

total 198 A 85 B 132 A 159A 691C 

Nov. 80 sedge 9 A 4 A 2 A 10 A 59 B 

grass 21 A 3 A 4 A 25 A 111 B 

vine 48 A 36 A 23 A 9A 45A 

forb 28 A 2 A 1 A 1A 35A 

total 106 A 44 AB 29 AB 44 AB 250 C 

Feb. 81 sedge 10 A 2 A 1 A 2 A 39 .B 

grass 21 A 3 A 4 A 8A 50A 

vine 41 A 8 B 27 AB 8 B 19 AB 

forb 1 A 1 A 0 A 1 A 9 B 

total 73 A 14 B 32 AB 17 B 116 A 

May 81 sedge 18 A 5 A 2 A 6 A 248 B 

grass 36 A 1 A 1 A 37 A 180 B 

vine 102 A 41 A 71 A 45 A 78 A 

forb 32 A 4 A 6 A 3A 154B 

total 189 A 51 B 79 B 91B 660C 

Aug. 81 sedge 22 A 12 A 4 A 18 A 36 A 

grass 56 A 13 A 31 A 25 A 295 B 

vine 138A 55A 46 A 92 A 340 B 

forb 27 A 3 A 11 A 1 A 300 B 

total 242A 82B 91 AB 136AB . 971 C 

a~lant group meas in horizontal columns not followed by the same letter 

differ significantly (P = 0.01). 
the area that had not been cut since 1933. 

Areas 3 and 4 had been cut several times in the 

1960's and were last cut in 1971, and generally 

had more forage than the uncut forest (area 2). 

Areas 3 and 4 had similar amounts of forage 

despite different stand conditions. 

Total forage ori the clearcut increased 41% 

from August 1980 to August 1981. Forage also 

increased by 232 on area 1 and by 15% on area 

4, but decreased 32 on area 2 and 31% on area 3 

in the August samples, 

Percent of the total forage in each plant 

group in the August samples of 1980 and 1981 on 

forested areas 1-4 was very similar. Areas 1-4 

averaged as follows: sedge - 102, grass - 202, 

vine - 602, and forb - 10%. Plant group averages were different on the clearcut: 

sedge - 12%, grass - 31%, vine - 22%, and 

forb - 35%. A marked change occurred in plant 

group percentages on the .clearcut from August 

1980 to 1981. Sedges declined from 19% to 4% 

and forbs declined from 40% to 31%, while vines 

increased from 9% to 35% of the total forage. 

Number of plant species in the forage 

sample was highest on area 1 (54) in August 

1980, but declined to 40 species in August 

1981. The other forested areas (2-4), had 

fewer species, with average numbers of 24 

(1980) and 19 (1981). In August the number of 

plant species increased from 30 (1980) to 35 

(1981) on the clearcut. 

Area 5 (clearcut) always had significantly 

more vegetative cover than the forested areas 

(Table 3). The least amount of cover generally 

DISCUSS IOK 

A recently clearcut bo tto~land hardwood 

tract consistently had the wost ratbit forage 

and vegetative cover. The improvement cut 

bottomland forest rank4 second in forage and 

cover 8 years after the cut, Two other mature 

bottomland hardkocd forec;ts that had received 

lighter cuts 9 years prior to sarcpling rabbit 

habitat conditions rank~d third and fourth ir, 

rabbit food and cover. However, differences in 

forage and cover among the forests were frequently not significant,, The hotto~~land hardwood forest that had not received any silvicultural treatment in about 45 years had tk,c lowest 

amount of forage and cover. 

The relationship of stand conditions to 

forage was not well deljnea ted. Konnerchantablr 

stems in the midstory and main canopy rot ably 

influenced 1 ight penetration (Chambers acd 

.Jenkins 1983) and affected rabbit forage and 

cover. 

Basically, any cutting improved rabbit 

forage and cover. Cover has frequently been 

mentioned as an important limiting factor for 

rabbit populations. Improvement or harvcst cuts 

not only permit increased vegetative gl-i -th on 

the forest floor (Carper 1969); they also add 

cover in the fom of tree tops, brush heaps, and 

stumps, which might be inportant vegetative 

structure or cover (Chapman and Fetdhamer 1981). 

Improvement cutting csear d openings which soon 

provided dense horizontal cover and increased 

forage for swamp rabbits, 

Table 3.--Cover rating (least squares mean in percent) on a density board 

from ground level to a height of 1.83 m, in 4 mature bottmlanri hardwood 

forests and a clearcut, Oktibbeha and Noxubee Counties, Mississippi, 1980- 

1981. 

Vegetative Cover ~~i~-:-- - 

Area Aug. 80 Nov. 80 Feb. 81 May 81 Aug, 81 

a~he highest rating possible was 240, which meant there was no vegetative 

b~~~~~'in the same vertical column not followed by the saor letter ure 

significantly (P < 0.01) dif fcrent. 

occurred on area 2, which had not been cut 

since 1933. Area 1, cut in 1972-73, always 

had the second highest average cover. Vegetative cover was similar on areas 3 and 4. 

Low cover ratings were recorded in 

February on the forested areas, but ratings remained at miximum on the clearcut even in 

February. Average cover increased slightly on 

all areas in August 1981 compared to August 

1980. 

Terrel (1972) reporred the swamp rabbit to 

be more common In selectively i ogged b~tc,~~n,i and 

hardwood traces than nature (unrst:t) trc r l -. The longevity of the effects sf sclirtivc 

or final harvest cuts was not deterz~ncd, bct 

the tracts that had been thinned 8 or 9 years 

prior to sampling mhbil: habitat conditions 

still exhibited slightly nore ferage aad cover 

than the tract that had not been thinned, The 

difference between thinned and unthinned, or 

degree of thinning, was, probajiy much greater 

during the first few years after cutting. 
A s i l v i c u l t u r a l sys tem recommended for 

southern bottomland hardwood forests (Putnam et 

al. 1960, Johnson 1970) includes clearcutting in 

small, 4-8 ha blocks to obtain natural regeneration. At age 20-25 years a commercial (pulp 

wood) hprovement cut would be conducted. At 

about age 40 another commercial (small sawtimber/ pulpwood) hprovement cut would be performed, Then at age 55-60 another sawtimber 

thinning would be conducted, followed by a final 

cut . (clearcut) at age 80. . According to the 

findings of this study this silvicultural system 

would maintain comparatively good swamp rabbit 

habitat throughout most of the rotation, particularly if the improvement and final cuts were 

well distributed throughout the bottomland. 

The Mississippi Cooperative Fish and Wildlife Research Unit supported this project . We 

thank E. Roberts, C. Hayes, and D. Cotton for 

their assistance. G. Weaver helped with timber 

cruise computer analyses, and W. Drapala conducted the statistical andlyses. We acknowledge 

the help provided by the senior author's wife, 

Phyllis, and graduate students J. Lipe, R. 

Spencer, D. frfartley, and.. J .. Bullock, and the 

field assistance by T. Tadlock and T. Morris. 

We thank Marcia Wise for edieing and typing the 

manuscript. 

LITERATURE CITED 

Allen, A. W. Habitat suitability index models: 

swamp rabbit. Biol. Rep. 82 (10.107) Habitat 

Evaluation Procedures Group, Div . Biol . Sciences, USDI, Fish & Wildl. Sen., Wash. D.C. 

1985. 20 pp. 

Bruna, 3. F. Evaluation of swamp rabbit release 

sites and habitat. Unpub. Fed. Aid Proj . NO. W-38-R-6. 1965. 8 pp. 

Carmer, S. G. and M. R. Swanson. Detection of 

differences be tween means: .. a Monte Carlo 

study of five pairwise mu1 tiple comparison 

procedures. Agron. J. 63:940-945; 1971. 

Chambers, J. L. and M. W. Jenkins. Understory 

light intensity in bo.ttomland hardwood stands, 

In: E. P. Jones, Jr., ed. Proc. second 

biennial southern silvicultural con£ . USDA 

For. Sen. Gen. Tech. pep. SE-24, Southeastern 

For. Exp. Stn., AshvilSe, N.C. 1983. pp. 

161-165. 

Chapman, J. A. and G. A. Feldhamer. Sylvilagus 

aquaticus. Mammalian Species 151: 1-4. 1981. 

Garner, G. W. Shortterm succession of vegetation following habitat- manipulation of bottomland hardwoods for swamp rabbits in Louisiana. 

Baton Rouge: Louisiana State Univ. ; 1969. 

147 pp. Thesis. 

Halls, L. K, and T. R. Dell. Trial of rankedset sampling for forage yields. For. Sci. 

12:22-26; 1966. 

Harris, L. D. Bottomland hardwoods: valuable, 

vanishing, vulnerable. Ff or ida Coop. Ext . Serv., Univ. Florida, Gainesville. 1984. 

18 PP. 

Hodges, J. D. and G. L. Switzer. Some aspects 

of the ecology of southern bottomland hardwoods. Mississippi Agr. and For. Exp. Stn. 

3. Paper No. 4087. 1979. 4 pp. 

Johnson, R. L. Renewing hardwood stands on 

bottomland and loess. In: S i l v i c u l t u r a l 

and management of southern hardwoods, 

Proc. 19th Annu. For. Symp. Louisiana 

State Univ. Press, Baton Rouge. 1970. 

pp. 113-121. 

Mullen, K. D. Aspects of the ecology of the 

swamp rabbit in disturbed bottomland 

hardwoods and associated .pinewoods in 

west-central Louisiana. M. S. Thesis, 

Northwestern State Univ., Natchitoches. 

1982. 59 pp. 

Pettry, D. E. Soil resource areas of Mississippi. Inf. Sheet 1278. Miss. Agric. and 

For.Exp. Stn., Miss. State. 1977. 4 pp. 

Putnam, 3. A,, G. M. Furniv-al, and J. S. 

McKnight. Management and inventory of 

southern hardwoods. USDA Forest Service, 

Agriculture Handbook No. 181. 1960. 

102 pp. 

Richardson, L. V. Food preferences and 

nutritive content of selected plants 

fed to cottontail and swamp rabbits. 

Baton Rouge: Louisiana State Univ., 

1963. 76 pp. Thesis. 

Scott, D. T., M. W. Carter, and G. R. Bryce. 

Rummage I1 analysis of ,.variance program. 

Brigham Young University, Provo, Utah. 

1981. 168 pp. 

Smith, M. W. Effects of selected silvicultural 

practices on swamp rabbit habitat. Miss. 

State : Mississippi State Univ. ; 1982. 

176 pp. Thesis. 

Steel, R. G. D. and J. H. Torrie. Principles 

and procedures of statistics. McGraw-Hill 

Book Co., New York. 1960. 481 pp. 

Sternitzke, H. S. Louisiana Forests. U.S. 

Dept. Agri. U.S. Forest,Serv. Resources Bul. 

50-7. 1965. 7 pp. 

Sullivan, A. D. Food preferences of swamp 

rabbits for selected plants. M.S. Thesis, 

Louisiana State Univ., Batan Rouge. 1966. 

57 PP. 

Terrel, T. L. The swamp rabbit (Sylvilagus 

aqua ticus) in Indiana. Amer . Midland Nat . 87: 283-295; 1972. 
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hardwoods along the Mississippi: a disappearing resource. USDI Fish and Wildl. 

Ser. pamphlet. 1978. 4 pp. 
Poster Session 

NATURALLY REGENERATED LONGLEAF PINE GROWTH AND YIELD RESEARCH 

b Y 

1 / John S. Kush, Ralph S. Meldahl, Stephen P. Dwyer, and Robert M. Farrar, Jr.- 

The range of longleaf pine (Pinus palustris 

Mill.) extends from southern Virginia to 

eastern Texas, primarily along the Atlantic and 

Gulf Coastal Plains with extensions into the 

Piedmont and Appalachian foothills of northern 

Alabama and Georgia. It is estimated that 

virgin longleaf pine forests once covered 30 to 

60 million acres of the Southeast. Today that 

estimate has been reduced to between 5 and 9 

million acres (Farrar 1978). 

From 1964 to 1967, the U.S. Forest Service 

established a regional longleaf pine study in 

the Gulf States. The original objective of the 

study was to obtain a data base for the 

development of growth and yield predictions for 

naturally regenerated, even-aged longleaf pine 

stands. Plots were installed to cover a range 

of ages, densities, and site qualities. 

The study consists of ZOO+ permanent 1110- 

and 115-acre measurement plots located in 

central and southern Alabama, southern 

Mississippi, southwest Georgia, and northern 

Florida. Plot selection was based upon a 

rectangular distribution of 4 age classes 

ranging from 15 to 100 years, 5 site-index 

classes ranging from 50 to 90 feet at 50 years, 

and 5 residual basal area classes ranging from 

16 to 165 square feet per acre. A description 

of plots by age, site index, and basal area is 

given in Table I. 

Each tree on the net plot (1110- and 1/5-acre 

measurement plot) with a dbh > 0.5 inch is 

numbered, has its dbh recorded to the nearest 

1110-inch, has its azimuth and distance 

relative to plot center measured, and its crown 

class 

L/ The authors are Forestry Research 

Specialist, Assistant Professor, and Forestry 

Research Specialist, School of Forestry, 

Alabama Agricultural Experiment Station, Auburn 

University, Ala., and Principal Mensurationist, 

Forestry Sciences Laboratory, Monticello, Ark. 

The research is a continuing cooperative effort 

by several private forestry organizations and 

public agencies, U. S. Forest Service (Region 8 

and Southern Forest Experiment Station), and 

Auburn University. 

determined. A systematic sub-sample of trees 

from each I-inch dbh class is permanently 

selected and measured for height to the 

live-crown base, total height, and if the tree is 

dominant or co-dominant, for age from seed. A 

112-chain isolation strip is maintained around 

each plot by thinning to the same residual basal 

area level as the net plot, 

The study accounts for change over time by 

adding a new set of plots in the youngest age 

class every 10 years. The project is now in its 

fourth measurement period (20th-year measurement) 

and the third set of new plots are currently 

being added. 

Using data from the first 5-year growth period, 

Farrar (1979) developed yield equations and 

tables to predict current and future stand 

volumes for thinned natural longleaf pine. The 

results were later updated with data from the 

second 5-year growth period (Farrar 1985). Data 

from the third growth period are,currently being 

analyzed. 

Growth and yield predictions for thinned, 

even-aged natural longleaf pine stands will be 

updated and expanded with results from the third 

and fourth 5-year growth periods. In addition, 

there are plans to develop individual tree and 

additional whole stand models. 

Current and future research will also 

investigate growth pattern changes over time. 

Establishing new plots in the youngest age class 

every 10 years provides a replication over time 

which will allow the examination of growth 

patterns over different 10-year periods (1965-75, 

1975-85, 1985-95). The genotypes are unknown, 

but all trees are of the same provenance. If 

growth patterns change significantly from period 

to period, the change should be detectable in 

these data. Then if change is observed, it 

should be possible to determine if it is abnormal 

through the use of concomitant data collected on 

site to account for variation due to climate and 

soil effects. 

The importance of long-term growth and yield 

studies with time replication is becoming 

increasingly obvious. If changes in growth 

patterns are to be identified and possible causes 

determined, it is imperative that studies such as 

this one be maintained as others are being 

establ ished. 
Table 1. Plot Assignments for the Regional 

Longleaf Growth Study 

Residual Basal Areas 

Age Site Original Current Projected 

C1 asses Index 30 60 90 120 150 30 60 90 120 150 30 60 90 120 150 

5 0 2 1 11 333 3 3 

60 244 4 3 221 2 13 2 2 

2 0 7 0 222 2 3 355 5 5 

80 334 2 1 333 3 1 123 2 4 

90 234 3 3 

5 0 112 2 1 1 

60 232 3 2 122 11 

40 70 323 2 2 232 2 1 

80 243 2 4 655 7 4 

9 0 333 3 3 223 2 3 

Literature Cited 

Farrar, Robert M., Jr. Silvicultural 

implications of the growth response of 

of natural 1y regenerated even-aged stands 

of longleaf pine (Pinus galustris 

Mill.) to varying stand age, site 

quality, and density and certain stand 

structure measures, Athens, Ga. 

University of Georgia. 1978, 

132 pp. Dissertation. 

Farrar, Robert M., Jr. Growth and yield 

predictions for thinned stands of even-aged 

natural longleaf pine. U.S. Dep. Agric. 

For. Serv. Res. Pap. SO-156, 78 pp. South. 

For. Exp. Stn. New Orleans, La. 1979. 

Farrar, Robert M., Jr. Volume and growth 

predictions for thinned even-aged natural 

longleaf pine stands in the East Gulf area. U.S. Dep. Agric. For. Serv. Res. Pap. 

SO-220, 171 pp. South. For. Exp. Stn, New 

Orleans, La. 1985, 
SILVICULTUmL GUIDELINES FOR FOREST STANDS THREATENED BY THE GYPSY MOTH: A S 

2 1 Kurt M. QottschalkAbstract.--Silvicultural treatments that may minimize 

gypsy moth impacts on hose hardwood stands are 

recommended based on ecological and silvicultural 

information on their interactions. Information on 

utilization of dead trees is provided. While these 

guidelines have not been tested, they represent the 

current knowledge of the iapacts of gypsy moth 

defoliation on forest staeds. 

Silvicultural treatments that may minimize gypsy 

moth impacts on host hardwood stands are 

recommended based on ecological and silvicultural 

information on their interactions. Decision 

charts are presented that match the proper 

prescription to existing stand and insect 

population conditions. Preoutbreak prescriptions 

focus on reducing stand susceptibility and 

vulnerability by increasing stand vigor, removing 

trees most likely to die, reducing gypsy moth 

habitat, reducing preferred gypsy moth food 

sources, improving predator and parasite habitats, 

and regenerating stands that are close to maturity 

or understocked. Regeneration cuttings before 

defoliation preserve: seed production, 

established advanced regeneration, and stump 

sprouting potential. Outbreak prescriptions 

prioritize stands for possible insect population 

control actions and regenerate stands that are 

close to maturity or understocked. Postoutbreak 

prescriptions rely on efficient salvage of dead 

trees and the regeneration of stands that are 

either understocked due to excessive mortality 

or are close to maturity. Information on 

utilization of dead trees is provided. While 

these guidelines have not been tested, they 

represent the current knowledge of the impacts 

of gypsy moth defoliation on forest stands. 

METHODS AND MATERIALS 

The use of these guidelines requires a stand 

examination, analysis of stand and insect 

characteristics, determination of the proper 

prescription using decision charts, and 

implementation of the prescription. The 

guidelines have been developed based on 

literature review of pertinent research and 

incorporation of this information into 

guidelines. 

'poster presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

'~esearch Forester, Northeastern Forest 

Experiment Station, USDA Forest Service, 180 

Canfield St., P.O. Box 4360, Morgantown, WV 26505 

RESULTS AND DISCUSSION 

Appropriate intermediate stand treatment 

prescriptions are determined by the proximity of 

infestation and when defoliation may be 

expected, coupled with stand characteristics and 

economic maturity. If the stand is not under 

immediate threat and defoliation is not expected 

within the next 5 years, there is adequate lead 

time in which to take preventive action. Seven 

silvicultural prescriptions have been described 

that may aid in reducing timber losses under these 

conditions. If the stand is poorly stocked (less 

than C-level; 35 percent) or if the stand is 

adequately stocked (C-level or better; 35 percent) 

but is within 5 years of maturity, you may wish to 

consider stand regeneration. Shortening the stand 

cycle will allow you to market the current stand, 

avoid lost value in the sale of dead salvage 

material, and assure adequate regeneration through 

seed production and stump spouting from the living 

trees, If advanced regeneration stocking and 

stump sprouting potentials are adequate, you can 

regenerate the stand with a presalvage harvest. 

For stands where these sources of regeneration are 

not adequate, then a presalvage shelterwood or 

sanitation conversion may be considered. If the 

stand is highly vulnerable or susceptible, then a 

conversion to nonpreferred species will help 

prevent the spread and establishment of gypsy 

moths. On lower quality sites, conversion will 

usually be to a pine species; higher quality sites 

can be converted naturally to mixed hardwoods 

using shelterwood or selection cutting. When 

stand susceptibility and vulnerability are low, 

then presalvage shelterwood cutting can develop 

adequate advanced regeneration but without 

requiring drastic change in composition. 

If the stand is fully stocked but will not 

reach maturity for another 6 to 15 years, it is 

advisable to defer cutting for 6 to 15 years, or 

re-examine for possible protection, early harvest, 

or salvage need after mortality has occurred. 

Fully stocked stands that may be 16 or more years 

from maturity and with less than 80 percent stand 

density may be handled best by deferred cutting 

---- for 10 to 15 years or re-examining status as 

defoliation becomes an immediate threat. 

Experience has shown that the stresses created by 

thinning or cutting remain for 3 to 5 years after 

treatment. Reduced vigor resulting from this 
stress, coupled with gypsy moth-caused 

defoliation stress, may yield much higher 

mortality losses. Thus, these higher value, 

highly stressed stands should be closely observed 

and possibly sprayed with insecticides if an 

outbreak is expected during the recovery period. 

For fully stocked stands that are 16 or more 

years from maturity and have greater than 80 

percent stand density, sanitation thinning or 

thinning may be considered, depending 

upon the percentage of the basal area that is in 

preferred food species. Sanitation thinning is 

designed to prevent the spread and establishment 

of dmaging organisms, to reduce stand 

susceptibility by removing preferred food species 

and refuges for the gypsy moth, and promote 

predator and parasite habitat. The treatment is 

best applied in stands where less than 50 percent 

of the stand basal area is in preferred food 

species, and where other management objectives 

will allow. Presalvage thinning reduces 

defoliation-caused losses by removing the most 

vulnerable trees before they are defoliated and 

killed. The major objective is to reduce stand 

vulnerability by early removal of those trees 

that are most likely to die. Presalvage thinning 

is best suited for those stand conditions 

described above, but in which more than 50 percent 

of the basal area Fs in preferred food species. 

The most vulnerable trees are poor crown oaks, 

poor crown other species, and fair crowned trees, 

particularly on poorer, drier sites. Good crowned 

trees are least likely to die. 

If defoliation is currently taking place or 

expected within the next 5 years, the most 

appropriate action is to protect foliage through 

insecticide application, to closely monitor and 

evaluate current conditions through stand 

examinations, or to move ahead with stand 

regeneration plans as described above. Stand 

priorities for insecticide application may be 

based on stand maturity, condition, and value of 

the stand; the severity of the gypsy moth threat; 

and planned management objectives. Under certain 

conditions of low stand value or low risk, the 

best course of action may be to delay direct 

treatment and to re-examine the stand after 

defoliation to assess current condition, extent 

of damage, and salvage potential. 

If defoliation has recently occurred, wait 1 

to 3 years to allow resulting mortality to 

occur, At that time, the stand can be 

re-evaluated to consider stand regeneration if 

damage levels are high and current stocking 

levels are poor, or stand maturity is within 10 

years. harvest can be used when 

regeneration stocking is adequate. When it is 

not adequate, then salvage shelterwood or salvage 

conversion can be used to obtain adequate 

regeneration or convert the stand to nonpreferred 

species as in the presalvage prescriptions. If 

damage levels are low to moderate, current 

stocking levels are adequate to maintain the 

stand, and the stand is more than 10 years from 

maturity, then several intermediate treatments are 

possible. Salvage thinning is used to salvage 

dead trees and thin live trees that are present 

until the stand reaches the proper residial stand 

density (B-level stocking). If the stocking of 

Live trees is between B- and CLlevel and there is 

at least 30 percent mortality, then a salvage 

cutting is called for. Otherwise, stands with the 

same stocking levels but less than 30 percent 

mortality should have deferment of further cutting 

until they increase in stocking, A more complete 

description of guides for ~ilvicultural treatment 

is presented by Gottschalk . 

Dying trees may be utilized for sawtimber if cut 

within 1 to 3 years of mortality. Increasing time 

after death will decrease the stumpage value, the 

quality of the lumber, and increase drying 

problems and checks. Veneer trees generally are 

downgraded to sawtimber status when they die. 

Trees dead up to 5 years are useable for pulpwood 

with no loss in quality or yield if bought by 

weight because the increased volume per ton of the 

dead trees offsets the increased fines and decay 

losses. 

CONCLUSIONS 

While these guidelines have not been tested, 

they represent the current knowledge of the 

impacts of gypsy moth defoliation on forest 

stands. Opportunities exist to manage forests in 

areas where the gypsy moth is or will be present 

in an economical manner without sacrificing 

management objectives or allowing the insect to 

dominate management actions as has happened in 

many areas of Pennsylvania, New York, and other 

infested areas. Eventually the forest, forest 

managers, and this exotic insect pest may 

approach a state of tolerable coexistance. 

3~ottschalk, Kurt W. Silvicultural 

guidelines for forest stands threatened by the 

gypsy moth. USDA For, Serv. Gen. Tech. Rep. In 

press. 
I?;TENS IVE PI,XNTXTIO?! i"NII:t?GEIIENT EF. FFG'I'S ON NUTRIENT POOLS : 

/ ."iCnSE STUDYCharles A. ~res'laz' 

Abstract.--Re-establishing loblolly pine plantations 

with the minimum of site degradation and cost will be of 

concern to landowners with plantations at or near rotation. 

Depleting the siteis macro-nutrients to the point of 

decreasing site productivity is one mechanism of site 

degradation. 

Kitrogen and phosphorus pools in the soil, forest 

floor, and vegetation are being monitored in a 17-year-old 

loblolly pine plantation in the coastal plain of Soutll 

Carolina. The monitoring was initiated about one year 

before harvest and will continue for 3 years after planting 

Within the stand, four site preparation methods will be 

used. Two additional stands of the same age but with 

different soil types will be added to the study. 

I NTRODUCTI 0% 

Site quality can be defined as the productive 

capacity of an area, andais a function of biotic 

and abiotic factors. Crop species genotype, 

radiant energy input, soil water content and 

mineral nutrients are the major growth limiting 

factors. Forest geneticists are improving the 

genotype of loblolly and the manipulation of light 

can be accomplished by competition control and 

stand thinning. Water manipulation is primarily 

a matter of draining excess water from the site. 

However manipulating mineral nutriants, especially 

the frequently limiting nitrogen and phosphorus, 

involves the soil and vegetation components. 

Fertilizers can be added at planting to supplement 

a deficiency, but this can be expensive and the 

effect often short-lived. h more biological, and 

perhaps economical, approach would be to preserve 

the on-site nutrients as much 3s possible through 

the harvest and site preparation operations. 

The purpose of this report is to outline a 

study that is monitoring the nitrogen and p'losphorus pools of a rotation-age loblolly pine plantation through re-establishment. Presious 

research has quantiiied the nitrogen and ~hosphorus cycling in older loblolly pine plantations, 

but little work has focused on the re-establishment 

phase of the rotation. Re-establishment is rhe 

part of the rotation that needs to be studied 

because during harvest and site preparation, the 

forest floor and understory vegetation is destroyed, 

thus decreasing the site's ability to retain nutrients. 

STUDY DESIGN 

The study design is randomized complete 

blocks within three stands. Each of three blocks 

in each stand will contain four treatment plots 

and one control plot. Site preparation treatments 

include : 

. shear, Jisk and bed, 

2. rebed at right angles to original beds, 

2nd inject residuals, 

3. herbicide before planting, inject residuals, and plant on old beds, 

2. same as 3, but with competition control 

for 1 year after planting, 

5. unharvested control. 

This design allows testing of the treatment 

effect for each stand and treatment and block 

effects for cotibined stands. 

In the field, treatment plots (203' x 200'; 

were installed with 50' buffers, and hithin each 

a 65' x 115' measurement plot was staked out. The 

measurement plot was oriented at right angles to 

the kindrows and included a section of the t~indrow. 

Field methods are divided into pre- and post1' Paper presented at Southern Silvicultural harvest* A 100°Q inventory was made of the trees 

Research Conference, Atlanta, Georgia, November with s?ecies, DBE and total height recorded. 

4-6, 1986. Understory vegetation in id' ?adius plots and 

greater than 3 feet tall was clipped at groundline, 3' Associate Professor, Baruch Forest Science dried and weighed. Vegetation less than 3 feet 

Institute of Clemson University, Georgetown, SC tall and the litter layer was sampled in 10-square29442. foot quadrats. -he tree inventory was used to 
determine the range of trees to be destructively 

sampled for biomass determination. Thirty pines 

and twenty hardwoods were felled and weighed in 

the field. 

Initial soil saqling was accoaplished by 

taking a coqosite sample at two depths (0-6" and 

6-12@'>, in the beds, interbed areas and windrows 

for all fifteen plots, These samples were analyzed for total nitrogen, amonium and nitrate, 

extractable phosphorus, potassium, calcium and 

magnesium, and organic carbon. Monthly soil 

samples of the bed areas at both depths are analyzed for ammonium and nitrate. 

Rainfall and throughfall are being collected 

in the open and control areas respectively. 

CURREKT STATUS AKD FiiTURE KORK 

As of NuvemSer 1885, the preharvest sarcpilng 

had been completed in one stan2 and that stand 

had been harvested. Site preparation is scheduled 

for July 1987 with planting in January 1988. Each 

September for three years soil and legetation 

samples will be taken. Seedlings and competing 

vegetation will be clipped and the litter layer 

removed in 10 square foot plots. The plot will 

be excavated to remove roots. Soil samples will 

be taken in the bed, interbed and windrow areas. 

Rainfall and throughfall.collection hiill continue. 

A second stand has been chosen and prekarvest 

sampling will begin immediately. The second 

stand was as productive as the first, but on a 

much better drained soil. To conplete the study, 

a third stand will be chosen with the same drainage characteristics as the first, but with a less 

productive soil. 
Site Preparation 

Moderators: 

Charles A. Hollis 

International Paper Company 

James A. Burger 

Virginia Polytechnic Institute 

and State University 

COMPETITION IN LOBLOLLY PINE PLANTATIONS 

FOUR YEARS AFTER REGENERATION 

USING SEVEN DIFFERENT SITE PREPARATION BTWODS 1/ 

Ted Needham, J.A. Burger, and C.W. Stafford '' 

Abstract.--Competition was measured during the fourth growing 

season in loblolly pine plantations that were established in the 

Piedmont using seven different site preparation methods. The 

extent and composition of the competition was assessed and 

relationships between tree size, various measures of competition, 

site preparation method, and preharvest vegetational 

characteristics were examined. The study shows that hardwood 

competition was not significantly less with increasing site 

preparation intensity and that the relationship between hardwood 

competition and tree size was weak. Apparently, other factors 

play an important role, either in combination with, or in place 

of competition to limit loblolly pine growth. 

INTRODUCTION 

Hardwood and herbaceous competition can be 

important factors limiting loblolly pine growth 

in the Piedmont of the southeastern United 

States. Research begining in the 1950's and 

extending into the 70% investigated the need for 

controlling competition following the conversion 

of hardwood stands and mixed pine-hardwood stands 

to pine plantations. The results show a 

significant and consistent increase in growth 

when pine seedlings were released from 

over-topping residual competitors compared to no 

release (Muntz 1951, Shoulders 1955, Miller and 

Tissue 1956, Batchell 1964) . Competition from 

understory vegetation, or that vegetation which 

predominates after the elimination of the 

overstory, can also affect the growth of pine 

seedlings. Current research is directed toward 

assessing this affect; however, the results have 

been less conclusive than with overstory 

competition (Carter et.al 1983, Cain and Mann 

1980, Stransky 1980, Bacon 1986). Overall, early 

control of competition, both understory and 

1; Paper presented at the Fourth 

Biennial Southern Silvi~ultural Research 

Conference, Atlanata, Georgia, November 4-6, 

1986, 

21 Graduate Research Assistant, Associate 

Professor, and Graduate Research Assistant, 

respectively, Department of' Forestry, VPl & SU, 

Blacksburg, VA 2406 1. 

particularly overstory, is considered essential 

for rapid growth and development of lobloliy 

pine. 

Survival and early growth of ioblolly pine in 

plantations is enhanced by site preparation (PehL 

and Bailey 1983, Lantange 1984, Stafford et al. 

19841, This improved perfomance is often 

attributed to early and effective control of 

overstory and understory competition. 

The objective of this study was to compare 

competition levels in four-year-old loblobly pine 

plantations that were established using seven 

different site preparation methods, and to relate 

these levels of conpetition to tree perfomance, 

A site preparation study was installed on 12 

mixed pine-hardwood sites in the South Carolina 

and Georgia piedmont in 1980 with the seven 

treatments described in table 1 replicated on 

each site. The treatments are not ail-inclusive 

of the many available alternatives; however, they 

represent the spectswra, covering a range of 

costs, methods (ie, chemical versus mechanical), 

and intensities of site disturbance, 

Competition was measured in fate smes of 

the fourth growing season around 756 randomly 

selected trees, The trees were located in 

pornanent plots in the treatment areas. Eaeh 

treatment and site wss equally represented. A 

circular plot whose radius was equal to the 

height of each sample tree was established and 

the following competition measurements taken: 
1) Total height and either ground line diameter 

(WL) or the crown dimensions of all 

hardwood stems by species, 

2) the height and crown dimensions of woody 

shrubs, 

3) an occular estimate of percent herbaceous 

cover, and 

4) a 1-5 ranking to reflect the tree's 

f ree-to-grow status. 

Species specific regression equations were used 

to convert crown dimensions to ground line basal 

area (Bacon, 1986 1. The free-to-grow ranking 

criteria used were similar to those proposed by 

the Virginia Division of Forestry (Dierauf and 

Garner) . 

The basic measures of competition were used 

both individually and in the derivation of 1) 

hardwood basal area per acre, and 2) percent 

hardwood basal area. Percent hardwood basal area 

is the proportion of total basal area in each 

plot consisting of hardwoods. 

Competition had been assessed the first and 

second growing seasons after site preparation 

using the line transect method. Estimates of the 

percent cover of various competition components 

were made (Lantange 1984), and these measures along with preharvest hardwood basal area were 

used to investigate changes in competition levels over time. 

Analysis of variance, regression and scatter 

diagrams were used to assess the effect of 

treatment on competition and the effect of 

competition on tree size. 

Table 1. Description of si-te preparation treatments applied on each of 12 sites in the South 

Carolina and Georgia piedmont. 

aUHBER TBZAMNT HACHINE PLANTING 

PASSES8 UETKCD DESCRIPTION .......................................................................... 

ti~ Preparation 0 Hand Ro #it* preparation follwing harvest. 

Rerb ic ida 0 Hand Clyphosate in water aerially applied in 

Burn mid Septenber at 3.9kglha ai. 

Burned 6 weeks later. 

Chop 1 Machine An empty 3mwide double drum offset 

Burn chopper behind a D7 tractor. Burned 2-6 weaka later. 

Shear dfac 1 Machine KO blade on Dl sheared and aligned debris 

while pulling tandem harrw (35" discs) 

to tilt the .oil. 

Shear 2 Hachina Residual vegetation sheered with a KO 

V-&bl.de dine shearing blade on first pars, 

Vdlede mount& to D7 crested mini vindrowe 

while pulling tandem harrow (35" diaca) 

Shear 2 &chine Residual vegetetion shear& with 1(0 blade 

adre on first pass. 

8la.h r&ed into wfndrwa on second pass. 

Shear 3 Hachine Residual vegetation sheared with KC blade. 

Bake Slash raked into windrare. 

Diec Soil di8c.d vith tandem harm 05" discs). 

RESULTS and DISCUSSION 

Treatment Comparisons: 

The percen: cover of herksceous, woody shrub, 

and hardwood competition after 4 years is 

presented in table 2. Except for the areas 

receiving no site preparation (33.3% herbaceous 

cover), herbaceous cover was similar among 

treatment areas, averaging 64.9%. There were no differences in the amount of hardwood cover among 

site prepared areas which averaged 208 compared 

to 35% in the untreated areas. Woody shrub cover was low, 1.4% on the average, and there was no treatment effect. The total percent cover shows 

that the sites were not fully occupied and 

competition for resources was only beginning to 

occur at age 4. 

The change in competition cover among 

treatments from year 2 to year 4 is also 

presented in table 2. All site-prepared areas exhibited a large increase in herbaceous cover, 

33% on the average; however, those that were disced exhibited the largest increase, 10-15% more than non-disced areas, Woody shrub coverage 

declined in a11 treatment areas and hardwood cover increased an average of 13.7%. Except for 

the chop burn and V-blade disc treatment areas 

which had greater hardwood cover increases on the 

average, the increases were similar among 

treatments. 

Hardwood basal area results are compared by 

treatment in table 3. There were no significant 

differences in hardwood basal area levels among 

treatments at age 4 with the exception20f the 

untreated areas which averaged 22.6 ft /acre and 

the herbicide burn areas which supporte g an average hardwood basal area of 10.6 ft. /acre. 

The very intensive shear rake disc treatment 

areas supported significantly lower levels 

averaging 5.2 ft /acre. In general, all 

treatments were equally successful in reducing 

the level of competing hardwood basal area. 

Percent hardwood basal area was significantly 

different between treatments; the disced 

treatment areas exhibited significantly lower 

levels than the non-disced treatment areas (Table 

3). Percent hardwood basal area is roughly 

inversely proportional to the average tree 

volumes in these treatments (Table 4). The 

smallest volumes are associated with the largest 

percent hardwood basal area levels; however, 

whether this is a cause and effect relationship 

is unknown since the effects of tillage interfere 

with a direct assessment of competition. 

The free-to-grow status of the pines was 

similar in all areas except the herbicide burn 

and untreated areas which averaged 2.0 and 3.6, 

respectively, compared to an average rank of 1.5 

for the other treatments (table 3). Even though 

the herbicide burn rank is greater than the 

others treatments, it is below the 2.5 rank used 

to indicate that a release treatment is justified 

(Todd 1983). 
Table 2. Fourth year Competition cover by treatment and changes in percent cover from year two. 

Herbaceous Woody Shrub Hardwood Total 

Site --------------- ---..------_----- ---------------- ------...--------- Preparation Year 4 Change Year 4 Change Year 4 Change Year 4 Change 

Treatment ------ ------ ------ ------ --_--- ------ ------ ------ 

(Pet. Cover) 

No Preparation 33. 3a1 -1.9 2 0.8a -6.3 35.0b 11.8 72.2a3 1.0 

Herbicide-Burn 61.9b 22.8 1.la -10.6 23.2ab 12.7 91.7b 16.5 

Chop-Burn 67.2b 30.6 l.9a -7.0 24.2ab 18.4 102.3b 35.3 

Shear-Disc 67.6b 39.3 2.0a -4.7 16.7a 12.9 96.5b 27.3 

V-Blade Disc 64.5b 36.2 1.2a -4.8 22.lab 16.9 96.0b 31.3 

Shear-Rake 64.4b 30.4 1.5a -3.4 18.9a 11.6 94.lb 26.9 

Shear-Rake-Disc 64.2b 39.6 l.la -5.0 15. la 12.0 93.533 34.3 

Average 64.9 28.1 1.4 -6.0 22.2 13.7 92.3 24.6 

Values are means of 12 observations. Each observation is a composite of 9 subsamples. Means 

within columns followed by the same letter are not significantly different at p C.05 

according to Duncan's multiple range test following an acrsine data transformation. 

Change. year 4 - year 2. 

Total cover includes pines. 

Table 3. Treatment cornpar-isons of hardwood 

competition after four &rowin& seasof'?. 

------------- ---- -------------- Percent 

Site Hardwood Hardwood Free- to-Grow 

Preparation Bas31 Area Basal Area Rank 

Treatment (Ft lacre) (Pet) 

--- -- 

No Preparation 22.6~ 85 d 3.6 

Herbicide-Burn 10.4b 68 c 2.0 

Chop-Burn 8.9ab 59 bc 1.6 

Shear-Disc 5.9ab 43 a 1.4 

V-Blade Disc 6.0ab 49 ab 1.4 

Shear-Rake 8.6ab 59 bc 1.6 

Shear-Rake-Disc 5.2a 43 a 1.3 

Values are means of 12 observations. Each 

observation is a composite of 9 subsamples. Means 

within columns followed by the same letter are not 

significantly different at p < .05 according to 

Duncan's multiple range test following an arcsine 

data transformation for variables expressed as a 

percent. 

Table 4. Treatment comparisons of average tree 

size after four growing seasons. 

Site Height Ground Line Volye 

Preparation (ft. ) Diameter (D ft) 

Treatment (in. 1 (in 1 

-- - - - - 

No Preparation 6.3 c 1.26~ 139 c 

Herbicide-Burn 6.6 c 1.57 b 202 c 

Chop-Burn 6.8 be 1.89 a 293 b 

Shear-Disc 7.3 ab 1.97 a 328 ab 

V-Blade 7.3 ab 1.93 a 318 ab 

Shear-Rake 7.2 abc 1.89 a 285 b 

Shear-Rake-Disc 7.5 a 2.05 a 380 a 

Values are means of 12 observations. Each 

observation is a composite of 9 subsamples. Means 

within columns followed by the same letter are not 

significantly different at p <.05 according to 

Duncan's multiple range test. 
ary, the sesults of treatment 

indicate that on the average, control 1 of grshzag-crest competition was achieved resulting 

in Low levels of competition in areas receiving a 

site preparation treatment. The type and 

intensity sf site preparation created only small 

differences in the levels of competition by age 

four. Mst of the difference occurred between the 

herbicide burn and intensive shear rake disc 

treatments. A competition problem was only 

beginning to prevail at age 4 as the stands were 

Just beginning to reach full occupancy. 

Individual Tree Assessment: 

The relationship between tree size and the 

competition variables was exmined both with and 10 20 30 40 50 EO 70 80 90 140 

without regard to treatment. Overall, no single PERCENT HERBACEOUS COVER 

competition variable explained a large portion of 

the variation in tree size. Hardwood basal area, 

percent hardwood basal area, and percent 

herbaceous cover were the competition variables 

most associated with tree growth. Other research 

has also shown them to be the best measures of 

the competition-tree size relationship (Bacon 

1986, Burkhart and Sprinz 1984, Glover 1982). 

Figure 1 illustrates the relationship of these 

variables with tree diameter. Diameter of the 

pines was generally more sensitive to tree size 

than height or volunae index. 

Across all treatments, no relationship 

between diameter and percent herbaceous cover was 

evident (Figure 1). Within individual treatments, 

percent herbaceous cover accounted for no more 

than 3% of the variation in dimeter, and this 

occurred in the chop burn treatment areas. The 

percent herbaceous cover within each treatment 

accounted for more variation in tree height than 

dimeter; however, it amounted to no more than 78 

of the total and was typically about 2%. 

The scatter diagrm between pine diameter and 

hardwood basal area shows only a weak 

relationship (Figure 1). Visual inspection of 

the relationship suggests that hardwood 

competition was not the predominant factor 

dfeoting pine dimster until the hardwood basal 

area exceeded 40 ft /acre. 

Percent hardwood basal area exhibited the 

strongest reia ioaship with diameter (Figure 1). 5 Ouerall, the R was 0.10. The strength of this 

relationship was entirely dependent on the 

small-dimeter erees occurring at the highest 

percent hardwood basal area levels. The pine 

trees affected by high levels of hardwoods are 

predominantly located in the untreated aseas; 

however, all treatments had some pines affected 

by high levels of hardwood competition. A11 

treated areas also had pines affected by the 

entire range of hardwood basal area. 

Multiple regression using hardwood basal 

area, percent hardwood basal area and percent 

hesbaceous cover provided no additional insight 

to the effect of competition on growth. 

A 

A AM1 A 

i 

A A A A 

AAASS A AAAA A1 L 

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OEWlftD1€QAA1AABASA 

OOEIII11D.4 IIAC A A ID$ BAA AA 1 A 1) 

EDCIUII kAlB E u wf as tc: AUA lQ5A h AACB AM A l EICWA A IAB &A A DA6AC A LA I) I* CAUS A A AA A AACA BA AA AA All A4 * IU1 A4 A kAA A A I&A A A A k A 

h I A * A a 

Figure 1. Scatter diagrams of the relationship 

I)et~~ceri tree diameter and various measures of 

competition. 
CONCLUSION 

Althou* there were significant differences 

in tree size among the seven site preparation 

alternatives after 4 growing seasons (Table 61, 

the evidence to suggest that competing vegetation 

was the predominant factor affecting tree size is 

weak. There were few significant differences in 

competition levels among the various treatments 

and individual tree assessments showed very weak 

relationships between tree size and competition. 

Only at high levels of competition was the 

relationship strong. Therefore, we conclude that 

competition alone was not the predominant factor 

limiting the growth of the pines on the site 

prepared areas examined in this study. This is 

not to say that in some instances competition was 

not the factor most limiting growth or that 

competition in combination with other factors 

was not limiting growth. Rather its occurrence as 

the most limiting factor did not prevail. 

ACKNWLEDGMENT 

The authors are grateful to Champion 

International Corporation for financial support 

of this study, and for the help received from 

their foresters, site preparation, and equipment 

personnel. 

LITERATURE CITED 

Bacon, C.G. 

1986. Interspecific competition in young loblolly 

pine plantations on the Virginia piedmont. 

Ph.D. Dissertation. Dept. of For. VPI & SU. 

Blacksburg, VA. 100p. 

Burkhart, H. E. and P. T. Sprinz. 

1984. A model for assessing hardwood competition 

effects on yields of loblolly pine plantations. 

VPI & SU, Sch. of For. and Wildlife Res. Pub. 

FWS-3-84. 55p. 

Cain, M.D. and W.F. Mann. 

1980. Annual brush control increases early growth 

of loblolly pine. South. J. Appl. For. 2:67-70. 

Carter, G.A., J.H. Miller, D.E. Davis, and R.M. 

Patterson. 

1983. Effect of vegetative competition on the 

moisture and nutrient status of loblolly pine. 

Can. J. For. Res. 14:l-9. 

Dierauf, T.A. and J.W. Garner. 

Free-to-grow classification. Virginia Division 

of Forestry. Charlottesville, VA 3p. 

Hatchell, G.E. 

1964. Mediate release needed for maximum growth 

of seeded loblolly pine. Tree Planters Notes 

No. 66. p 19-22. 

Lantange, D.O. 

1984. An evaluation of site preparation methods 

for the regeneration of loblolly pine in the 

South Carolina and Georgia piedmont, Ph.D. 

Dissertation. Dept. of For. VPI & SU. 

Blacksburg, VA. 200p. 

Miller, M.D., and O.C. Tissue. 

1956. Results of several methods of release of 

understory loblolly gine in upland hardwood 

stands. J. For. 54:188-189. 

Muntz, H.H. 

1951. Converting scrub oak areas to pine 

plantations. J. For. 49:714-715. 

Pehl, C.E. and R.L. Bailey. 

1983. Performance to age ten of a loblolly pine 

plantation on an intensively prepared site in 

the Georgia piedmont. For. Sci. 29:96-102. 

Shoulders, E. 

1955. Release underplanted loblolly early. USDA 

For. Serv. South. For. Note No. 100. South. For 

Exp. Sta., New Orleans, LA. p 2-3. 

Stafford, C.W., J.L. Torbert, and J.A. Burger. 

1984. An evaluation of site preparation methods 

for loblolly pine regeneration on the Piedmont. 

Proc. Third Biennial South. Silvi. Res. Conf. 

Atlanta, Ga. USDA For. Serv. South For. Exp. 

Sta. Gen. Tech. Rep. SO-54. p 57-60. 

Stransky, J.J. 

1980. Vegetation response to various methods of 

site preparation. Feb. 1980 Progress Rep. 

Summary. On file: USDA For. Serv. South. For. 

Exp. Sta. Nacogdoches, TX. 

Todd, S.D. 

1983. A method for evaluating and prioritizing 

loblolly pine plantations for release. Champion 

International Corp. Coop. Res. Note SE-84-01. 

lop. 

Glover, G.R. 

1982. Evaluation of competing vegetation effects 

on growth of young loblolly pine plantations in 

the Alabama piedmont. Unpub Ph.D. Dissertation. 

VPI & SU, Dept. of For. Blacksburg, VA 24061. 

141 p. 
Soil Density and Harvest Slash Ef ts on 

Four-Year-Old Loblolly Pin3 

Abstra of logging slash and forest floor layers in the process of 

Prepar r forest land for pine plantations my rduce site quality and 

plantation yields. The effects of alternative site treatntents on organic 

residue, soil tilth and loblolly pine growth after four years we 

eight cut-over forest sites in the South Carolina and Georgia Pi 

treatments were: 1) shearing and discing in one pass; 2) sheari 

and discing in two passes; 3) shearing and windrowing in two pas 

shearing, windrowing and discing in three passes, Residual logging debris 

remaining on non-windrowed areas was aligned into "miniwindrows" between 

tree rows with a V blade on the planting tractor. After four years, tree volume 

index was highest on sheared, windrowed and disced treated areas, but 

fourth-year height increment was the mng all treatments. Preliminary 

results suggest that higher levels of harvest slash and litter and lower soil 

densities on non-windrowed and disced plots could result in superior long-term 

growth, 

against the concodtant nutrient 

redistribution and partial depletion that also 

occurs. Morris and workers (1983) found 

that windrowing on a flatwoods soil resulted in 

atover tierlands in the southern Piedmont the loss of mre than 350 kg PJ/ha, an munt 

are often intensively site prepared by which was greater than 10% of the total N shearing, windrowing and discing to clear content of the undisturbed forest emsystem, or residual debris, reduce competition and enhance aut the sarne munt that would have been machine planting. Survival and early growth on renw>ved in six mnventiondl. harvests, sites treated in this fashion are usuallv 

@roved; however, it is unknown whetheF the 

initial growth advantage obtained by this 

treatment will persist for the duration of the 

rotation, or if final yields will justify the 

high cost of this treatment. Stafford and 

rkers (1984) reported that shearing, 

wing, and discing resulted in better 

survival and growth after three years than 

treamnts such as chop and burn, spray and 

owing without discing. I&e 

s of this three-pass intensive 

ung established stands includes 

reduced competition, soil tillage, and 

increased levels of available nutrients. 

Despite these regeneration advantages, many 

foresters are concerned that the initial 

benefits of such intensive site preparation may 

be at the expense of long-term productivity. 

Shearing and windrowing prepares the 

cut-sver forest site for planting by removing 

wanted residual vegetation and harvest slash. 

Burning the windrows clears the site of debris 

so that the entire harvested area can be 

planted, These benefits should be weighed 

urnper presented at the Fourth Biennial 

Southern Silvicultural Research Conference, 

Atlanta, Georgia, 

Z/Research Associate, Graduate Research 

Assistant, Associate Professor , respectively 

Department of Forestry, Virginia Polytechnic 

Institute and State University, Blacksburg, 

VA 24061, 

After reimval of surface debris, 

incorporation of the remaining litter layer in 

the soil surface by discing causes accelerated 

decompsition and premature release and 

availability of organiely-eombhed nutrient 

reserves. Fox and coworkers (1986) found that 

45% of the available N reserves were 

mineralized during the first year on a cut-over 

Pielhnont site in Virginia that had been 

sheared, windrowed and disc&. The long-term 

effect of raving such large portions of the 

nutrient reserves is unclear because no study 

has documented the balance between nutrient 

requirement and availability for the duration 

of a tree crop. Perhaps the best evidence of 

possible long-term detrimental effects of 

windrowing are results of an analysis by Fox 

and others (1985) of adjacent 31-vear-old 

loblolly pine stands growing on d~orth 

nt site, half of which had G-en 

burned and the other half windrowed. The stand 

on the portion of the site prepared by burning 

had a site index (base age 25) that was 16.4 

feet higher than the stand on the adjaent 

windrowed area; the stand volm was (Ilmst 1.5 

times greater, This treatment effect probably 

represents the extreme since an earlier report 

on the progress of these stands by Glass (19761 

indicated that a considerable munt of topsoil 

had been scalped and dqsited in the windrows. 

Disc harrowing reduces the aunts of 

cowting and herbaceous weds, but it 

also prepares a forest site for planting by 

loosening naturally dense or compacted soils, 

Foil and Ralston (1967) demonstrated a negative 
linear relationship between root weight andj 

bulk densities ragging from 0.8 to 1.4 g/cm . Dense soils lhiit gas exchange ;uzd available 

water, and physically retard root growth. 

However, PeN. and Bailey (1983) reported that 

positive early resmnses of a loblolly pine 

stmd to discing in Georgia were hardfy 

detectable by age 10. It is possible that the 

inftital loosening effect that discing has on soils with pr strtaGture decreases with time as rainfall puddles and recowcts soils that 

have no protective Litter Layer. 

With the prospect of possible site 

productivity and yield declines after a well-document& early positive response to 

shearing, windrowing, and discing, the 

objective of this study was to assess the 

benefits of a similar but alternative treatment 

consisting of shearing, followed by discing and 

slash displacement between tree rows using a V-blade attached to the tractor pulling the 

tree planter. 

A aomplete description of the Champion 

International Corporation--Virginia Tech 

Cooperative Site Preparation Project was described in detail by Lantagne and Burger 

(1983). The study involves seven site 

preparation treatments replicated at twelve 

sites in the 5233th Carolina and Georgia 

nt. This report concerns only four of 

these treamnts: 1) shearing, windrowing, and 

discing (shear-windroM-disc) ; 2) shearing and 

whdrowing (shear-windrow); 3) shearing and 

discing (shear-disc) ; and, 41 shearing, V 

blading and discing (shear-V blade-disc). The 

shear-disc and the shear-!! blade-disc 

treatments were both designed to provide soil 

tillage, while allowing the harvest slash to 

remain on site. Be debris was aligned into 

"mini-windrows" on 10-foot centers with a V 

blade during site preparation on shear-V 

bladdisc treamnt areas, and by a V blade on the planting tractor on shear-disc treatment areas. 

For this study, nine trees were selected in 

each treatment area at eight study sites, 

resulting in a total of 72 sarnple trees per 

treatment, Wcause no significant differences 

were found between the shear-disc and shear 

V-bladdisc trea-nts with respect to tree 

growth or soil meaurements, data were averaged 

to simplify the interpretation of treatment 

effects, Cohining these two treatments 

(hereafter referred to as "shear-disc") 

prsducd a sample size of 144 trees. 

The soil was intensively sampled around each 

tree in an effort to determine which soillsite 

factors were havhg the greatest effect on tree 

growth. Soil bulk den~ity and litter samples were taken at four locations around each tree. 

Tw samples were collected from within the 

planting row (on each side of the tree). 

3ho sexes were collected between planting 

rows, 

After four years, tree volw index in the 

shear-windrodisc trea-nt plots was significanay larger than that in the 

shear-windrow trea-nt plots table 19. 

Volume index in the shear-disc treatment plots was not signifimtly different from the 

others. These differences among treahnents 

follow the same pattern reported after the 

first and third growing setasons (Mhgne and 

Burger, 1983; Stafford et al,, 1985). Better 

growth on the shear-windrowilisc plots m~red 

to the shear-windrow plots has been attributd 

to soil loosening and elevated levels of soil 

nutrients resulting from the incorporation and 

subsequent mineralization of the litter layer. 

Growth during the first four years on the 

shear-disc plots may have been slightly lower 

than on shear-windrodisc plots due to some soil scalping by the V-blade on the pla~ting 

tractor. Where scalping occurred, seedlings 

did not receive the benefit of soil tillage and were often planted in dense subsoils. 

There is evidence that the greater initial 

growth rate of trees in the shear-windrow-disc 

plots is beginning to diminish after four 

years. Height incremnt for the fourth year was identical for all treatment plots. All 

treatments resulted in an average height 

increase of about 36 in (Table 1). Furthemre, 

when expressed as a percent increase in total 

height, the shear-windrow-disc plots had the 

lowest relative growth. In the study by Fox and 

others (19851, stem analysis revealed that 

growth on the windrowed site started to decline 

relative to the burned site at age eight. 

---- Table 1. Sfect of site prepration treatment 

on 4-year-old tree volume and 4thyear height increment 

-_---- 

Site 4th Year Growth 

Preparation - -- Treatrent Volume Index Height Relative 

Shear, Windrow 380 b2 

Shear, Disc 442 ab 36a 79 a 

Shear, iqindrow, 540 a 36a 66 a 

Disc 

2 bolurrte Index = (Diameter) x Height. 

2~alues within a colm followed by a different 

letter are significantly different 

(P 1. 0.05). 

-- -- 
meficial effects of tillage on surface 

mil bulk density was probably a causal factor 

for superior growth on the shearwindrow;-disc 

plots during the first four years, However, 

s collected after the fourth 

were lower than both of these treatments. Bulk 

density samples collected between planting rows in t9e shear-disc treatment plots averaged 0.16 

g/m lower than samples mllected within the row. Lower between-row bulk densities in 

shear-disc treatment plots resulted for two reasons: 1) some scalping within rows occurred 

during planting; and, 2) organic debris that 

was left on site between rows protected 

loosened soil from the conpacting and puddling 

effects of rainfall. 

Litter samples collected after the fourth 

growing season show that the shear-disc 

treatments have mre organic matter on the site 

(Table 31, with almst three times as much 

litter between rows compared to windrowed 

plots. It was apparent during sampling that 

where these mini-windrows existed, underlying 

soil tilth remained excellent. 

With time, we expect pine roots in the 

shear-disc treatment areas to fully exploit the 

loose soil beneath this litter, resulting in mre rapid growth of trees than might be 

expected in the shear-windrow-disc or 

Table 2. Effect of site preparation treatment on soil bulk density within and 

between the rows 

Site Surface Soil Bulk Density (g/cm3) 

Preparation 

Treatment within-row between-raw difference 

T&le 3. EEfect of Site Preparation Treatment on Surface Organic Debris 

Site Surface Organic Debris (g/mL) 

Preparatio~ 

Treaant wi"c'nin-row between-row difference 

Shear, 

Windrow 390 b l 579 b 189 b 

Shear, 

Disc 505 a 1399 a 894 a 

Shear, 

Windrow 

Disc 381 b 455 b 74 b 

balues within a column followed by a different letter are significantly 

different (P _( 0.05) . 

shear-windrow plots. In addition to the 

beneficial effects of a looser soil, the 

"mini-windrowsn should result in greater levels 

of available soil moisture by reducing runoff, 

by providing increased levels of organic matter 

to hold moisture, and by protecting the surface 

from the drying effects of sun and wind. 

Furthe,mre, residual logging debris should act as a slow-release nutrient source, releasing M 

and other essential elements to the trees as 

decomposition occurs. This slow release should 

become inp>ortant as the stand approaches closure 

and nutrient demands reach a peak. In contrast, 

growth of the trees on the shear-windrow-disc 

treatment areas could decline relative to growth 

of trees on shear-disc treatment areas since 

most of the N reserves on these plots was remved by windrowing or released by the initial 

mineralization of the litter layer. 

Btation-length studies are needed to confirm 

the preliminary results from this and other 

studies, In the interim, foresters should 

strive to prescribe site-specific treatments 

that enhance site quality at the lowest cost. 

Shear, 

Windrow 1.26 a 1.19 a 0.07 b 

Shear, 

Disc 1.24 a 1.11 b 0.16 a 

Shear, 

Windrow, 

Disc 1.22 a 1.20 a 0.02 b 

hues within a colm followed by a 

different letter are significantly 

different (P I 0,05) . 

Foil, R. R, and C. W. Ralston. 1967. The 

establishment and growth of loblolly pine 

seedlings on compacted soils. Soil Sci. Soc. 

Am, Proc. 31:565-568. 

Fox, T. R., J. A. Burger, and R. E. Kreh. 1986. 

Effects of site preparation on nitrogen dynamics 

in the southern Pi&mnt, Forest Ecology and 

Managent 15:241-256. 

Fox, T. R., L. A. orris, and R. A. Maimne. 

1985, Thirty-year results from a windrowing 

study in the North Carolina Piedhnont, Agronomy 

Abstracts:218. 
Glass, G, G. 1976, The effects from rootr&ing 

nt logfolly pine ( 

L.) site. Tech, Rep. 56, Nee, State Forest 

Fertilization Coop., Raleigh, N.C. 

Lantagne, D. 0. and J, A, Burger, 1983. 

First-year survival and growth of loblolly pine 

as affected by site preparation on the South 

Carolina and Georgia Piedmont, p. 5-10. .I&: E, 

P. Jones (&, 1 Prom&ws 

Southern Silvicultural Research Conference, 

plkov. 4-5 1982, Atlanta, Gr\. USXI For. Serv. 

Gen. Tech. Rep, SE-24. 

PE?kl, G. E. and R, L, Railey. 1983, 

ce to age ten of a loblolly pine 

tensively prepare3 site in 

t, For. Sci. 29:96-102, 

Stafford, C. W,, J, L. Tcrrbert, and J, A, 

Burger. 1985. An evalmtion of site 

s for loblolly pine 

nt, p, 57-60, &: El 

Shoulders (ed .I Procedings 

Southern Silviculturdl Research Conference, 

Fbv. 7-8 1984, Atlanta, GA USDA For. Sew. Gene 

Gech. Rep, 523-50. 

Norris, L. A., W. L. Pritchett, andB. F. 

Swindel. 1983. Displacement of nutrients into 

windrows during site preparation of a flatwood 

forest. Soil Sci. Soc. Am, J. 47:591-594. 
Charles R. err^^ 

Abstract.--Subsoiling significantly improved early 

growth of. loblolly and shortleaf pines (19 and 38 percent, 

respectively, after 5 years) on a severely eroded Piedmont 

site in Georgia. At the Savannah River Forest Station in 

South Carolina, subsoiling improved growth of loblolly pine 

on a borrow pit (43 percent after 7 years), and sweetgum 

on an Orangeburg soil (47 percent after 2 years). Subsoiling was consistently better for tree growth than * 

disking. Roots of loblolly pine grew to the bottom of a 

subsoiled trench (up to 1 m) in 2 years, but they did not 

go deeper than about 15 cm on plots that had only been 

disked. Trees have grown faster on plots amended with 

sewage sludge than on plots amended with fertilizer. 

Deep subsoiling, i.e., ripping to a depth of 

60 cm or more, has been used to a limited extent 

as a means of preparing problem sites for planting 

tree seedlings. Sites needing such treatment and 

the specific benefits of treatment, however, have 

not been well defined. 

Moehring (1970) recommended subsoiling to 

alleviate compaction damage and to break up shallow 

hardpans and impervious subsoil layers. Wilson 

(1969) advocated such treatment for soils in New 

Zealand, and Page (1977a, 1977b) compared subsoiler 

designs for use in New Zealand. Schroder (1975) 

found that although effects of subsoilng persisted 

for up to 2 years, effective field moisture capacity was not improved. Guild (1971) showed that in 

New Zealand subsoiling improved survival and, in 

some cases, height growth of planted Monterey pine 

(Pinus radiata D. Don). The Cities Service 

Company, and more recently the Tennessee Chemical 

Company, have used deep subsoiling as a site preparation method for tree planting in the Tennessee 

Copper Basin (James George, pers. commun. 1983). 

In numerous reclamation research studies by the 

U.S. Forest Service in the southeast, subsoiling 

has been employed as a site preparation nethod 

with generally favorable responses (Berry 1977, 

1979a, 1982, 1983; Berry and Marx 1978; Kormanik 

and Schultz 1985; Ruehle 1980). 

Subsoiling is regarded by some as a beneficial 

part of site preparation for the establishment of 

trees and is carried out routinely by timber companies such as Weyerhaeuser (John Mexal, pers. 

commun. 1983) and Union Camp (Robert Herren, pers. 

Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

Principal Plant Pathologist , Southeas tern 

Forest Experiment Station, U.S. Department of 

commun. 1983). Recently the Champion-International 

Paper Corporation initiated subsoiling field trials 

(David Oliff, pers. commun. 1983). 

Berry (1979b) found that growth of both shortleaf (P. eehinata Mill.) and loblolly (P. taeda L.) 

pines could be significantly improved by subsoiling 

with furrows 0.8 m apart and 0.6 to 0.8 m deep on 

a severely eroded site (Madison soil series). In 

a borrow pit reclamation study it was found that 

after 4 years subsoiling improved growth of loblolly 

pine and that depth was more important than spacing 

of furrows or whether furrows were parallel or in 

a grid pattern (Berry 1985). 

This-paper reports more recent data from these 

two studies, conducted on low-quality sites, and 

gives 2-year data from a third study carried out 

on a high-quality site. 

The primary objective of earlier work leading 

to these experiments was the development of techniques for reclamation of adverse sites. In 

numerous experiments, including two of the three 

described in this paper, sewage sludge was tested 

as an amendment. It is now obvious from these data 

as well as data from other experiments that wellincorporated sewage sludge followed by deep subsoiling constitutes a superb site preparation 

treatment (Berry 1977, 1979a, 1979b, 1982, 1983; 

Berry and Marx 1978, 1980). For this reason it is 

necessary to comment rather extensively on the 

effects of sewage sludge both alone and in combination with subsoiling. 

In all cases, sewage sludge produced faster 

tree growth than fertilizer for periods of from 

2 to 10 years, the periods covered by these studies. 

In sewage sludge studies, where a "no treatment" 

control was installed in addition to a fertilizer 

treatment (Berry 1986), it was found that a single 

application of 560 to 1,120 kg/ha of 10-10-10 plus 

2,240 kg/ha of dolomitic lime produced little, if 

any, increase in growth over the control plots. 

Agriculture, Forest Service, Athens , GA 30602. 
Measurements of height and DBK or root-collar 

diameter of trees were taken in all studies. When 

root-collar diameter was obtained, values for D~H 

(root-collar diameter" total height) were computed and all data summarized. D2H has been shown 

to be a reliable surrogate measure for aboveground 

biomass for loblolly pine and it also appeared to 

be a useful surrogate measure for stem weight and 

stem volume (Hatchell and others 1985). 

MADISOX SOIL EXPERIMENT 

Methods 

the long-term effects of this treatment may be 

positive, no benefits could be detected when data 

were taken. 

Subsoiling, however, was beneficial to both 

loblolly and shortleaf pines. With loblolly, subsoiling increased height growth by 3.5 percent and 

root-collar diameter growth-by 3.4 percent, and 

the resulting increase in DLN of 19.3 perce,, "t was 

statistically significant (table I). Subsoiling 

increased height growth of shortleaf by 17 percent 

root-collar diameter growth by 15 percent, and 

D~H by a significant 38 percent over controls aftel 

5 years. 

This experiment was installed in Elbert 

County, Georgia, where low-quality mixed hardwoods 

and pines had been harvested within the previous 

6 months. After harvesting, the site was rootraked and windrowed. The soil was classified as 

Madison series and texture of the topsoil was sandy 

clay loam in two of the three study blocks and 

sandy loam in the third. Erosion had been extensive on this "littleleaf" site because of poor 

agricultural practices in the past, and on many 

plots most of the original topsoil was gone. 

A split-plot design with three replicate 

blocks was employed. Half of each block was subsoiled (major plots). Subsoiled furrows were 

spaced 0.8 m apart and 0.6 to 0.8 m deep. Each 

block contained eight minor plots, with half of 

each plot in the subsoiled area. Four randomly 

selected plots in each block were planted with 

1-0 loblolly pine and four with 1-0 shortleaf pine 

seedlings. Spacing was maintained at 3.0 m between 

rows and 1.5 m within rows without regard to 

furrows. Subsoiling was carried out in late winter 

just before planting. Minor treatments applied 

to each species were (I) control (no treatment), 

(2) 8-em-deep broadcast application of pine bark 

prior to subsoiling, (3) sowing of Lespedeza 

serieea (Thumb.) Benth. (67 kg/ha), and (4) interplanting with black locust (Rcbinia ~seudoaeacia 

L.}. 

Loblolly pine, shortleaf pine, and black 

locust seedlings were obtained from Georgia Forestry Commission nurseries and planted in early 

March. Many seedlings did not survive planting 

shock and a spring drought, so vacant spaces were 

replanted in late April. 

Fusiform rust incidence was recorded after 3 

years. After 5 years, height, root-collar 2iameter, 

and survival were recorded. All data were subjected to an analysis of variance. 

Results 

After 5 years, growth of pines had not been 

improved by bark applications, interplanting with 

black locust, or sowing hespedeza sericea. The 

bark that was available for the study, even though 

it was several years old, contained a lot of undecomposed wood chips. For at least the First 2 

years, growth of pines in bark-treatment plots 

was retarded because of competition for soil 

nitrogen by wood-decay microorganisms. Although 

BORROW PIT EXPERIMEKT 

Methods 

This study was installed on a borrow pit 

originally overlain with Gunter sand. During the 

creation of the borrow pit, several feet of soil 

were removed, exposing a compact subsoil and thus 

creating site conditions too severe for economical 

timber production. AIL vegetation, consisting 

mostly of scrubby pines, was removed with a bulldozer. Eighteen treatments (2 amendments x 9 

mechanical site preparation treatments) were randomly assigned to 15.5 x 15.5 m plots in each of 

five blocks. Plots were separated by aisles 8 m 

wide. Anaerobically digested sewage sludge containing 1.8 percent N, 0.71 percent P, 0.024 

percent K, 366 ppm Mg, 117 ppm Fe, 93 ppm Mn, and 

53 ppm Zn was obtained from Macon, GA. Sludge 

was analyzed for nitrogen by Kjeldahl, and all 

other elements by extraction with concentrated HN03 

and analysis by Plasma Emission Spectrograph at 

University of Georgia laboratories. Sewage sludge 

was applied to nine plots in each block at a rate 

of 17 Mg/ha. Fertilizer (10-10-10) and pulverized 

dolomitic limestone were applied at a rate of 1,121 

kglha and 2,242 kglha, respectively, to the remaining nine plots in each block. Amendments were 

applied in September 1978 and incorporated by 

double-disking to a depth of 15 em. 

Nine physical treatments were carried out on 

both fertilized plots and plots amended with sewage 

sludge in each block. The mechanical site preparation treatments were carried out as follows: 

(1) Disking only (no subsoiling). 

(2) Disking plus subsoiied furrows in one 

direction, 110 cm apart, 32 cm deep. 

(3) Disking plus subsoiled furrows in one 

direction, 110 cm apart, 46 cm deep. 

(4) Disking plus subsoiled furrows in one 

direction, 220 cm apart, 92 cm deep. 

(5) Disking plus silbsoiled furrows in one 

direction, 220 sn apart, 46 cm deep. 

(6) Disking plus subsoiied furraws in two 

directions, 110 ctxi apart, 92 cm deep. 

(7) Disking plus subsoiled furrows in two 

directions, 110 cm apart, 46 cm deep. 

(8) Disking plus subsoiled furrows in tvo 

directions, 220 cm apart, 92 cm deep. 

(9) Disking plus subsoiled furrows in two 

directions, 220 cm apart, 46 cm deep. 
Table 1.--Effects of subsoiling on survival and growth of loblolly and shortleaf 

pines after 5 yearsd/ 

----- 

Fusif om 

b / Root- rust infection 

Major plot Survival aft= collar Cronarti-m 

treatment 2 years 5 years Height diameter II2@/ bushes trees- d / - - Percent - - cm cm' x 10' - - Percent - - - - mm 

LOBLOLLY PINE 

Subsoiled 98.la 58.3a 318a 81a 22.4a 11.9a 6.25a 

Not subsoiled 96.1a 77.6a 307a 74a 18.8b 5.4b 12.50a 

SHORTLEAF PINE 

Subsoiled 98.0a 94.8a 189a 51a 5.9a - - -- Not subsoiled 93.9a 89.6b 162a 44a 4.3b - - -- 

a/ Treatment means within a column followed by the same letter do not differ 

significantly at P = 0.05. 

h/ C~*onnrLiw? bushes are not included as survivors. 

C/ (Root-collar diameter) x height. 

di None of these trees are Crorartim bushes, but all became infected after 

planting. 

a/b/ Table 2. Chemical analysis of borrow pit soil 1 year after application of amendments- - 

--- Organic - 

Treatment N P K Ca Mg Mn Z n Cu pH matter CEC --- ------------ppm------------- c / Percent meq/100 g 

Fertilizerdisked 77b 14b 16ab 198a 89a 0.27b 0.07b 0.02b 6.04a 0.23a 1.60a 

d/ Sludgedisked 249a 50a 8b 187a 13c 3.09a 6.98a 0.29a 4.38~ 0.23a 1.86a 

~erti~ize&' 

disked 73b 7b 22a 106b 55b 0.79b 0.30b O.OOb 5.06b 0.21a 1.70a 

dl Sludgedisked 227a 38a 8b 158ab 17c 2.50a 5.43a 0.21a 4.46~ 0.38a 1.92a 

- 

2' Treatment means within a column fallowed by the same letter do not differ significantly at P = 0.05. 

Plots sampled were those not subsoiled (disked) and those which received the maximum degree of 

subsoiling, i.e., two directions with furrows 110 cm apart and 92 cm deep, 

2' 1,121 kg/ha 10-10-10 fertilizer and 2,242 kg/ha pulverized dolomitic limestone. 

4' 17,000 kg/ha (E = 1.8%, P = 0.71%, K = 0.024%). 
During the autmn of 1978, the study site 

was seeded with Ky 31 fescue (Fastuca amndinacea 

Schreb.) at 34 kgiha. 

The study site was planted in March 1979 

with loblolly pine seedlings (Livingston Parish 

source) inoculated and heavily colonized (Pt 

index 88) by the ectomycorrhizal fungus, PisoZithus tinctorius (Pers.) Goker & Couch. They 

were graded to a root-collar diameter of 3.0 to 

4.5 am and a height of 16 to 19 cm. Seedlings 

were planted at a spacing of approximately 2.2 m 

x 2.2 m and always in a subsoiled furr~w except 

on disked-only plots. No weed control was 

necessary. 

Growth data were collected in the autumn of 

1982 and 1985. Soil was analyzed 1 year after 

planting. A soil sample composited from five 

subsamples per plot taken at a depth of O to 15 

cm was airdried at room temperature for 10 days 

and chemically analyzed after double acid extraction (0.05 N HC1 + 0.025 N H2S04). P was determined colorirnetrically and cations by atomic 

absorption. Total N was determined by Kjeldahl, 

organic matter by wet oxidation chromic acid 

digestion, CEC by saturation with NHL++ and replacement with K+, and pH by a glass electrode 

in a mixture of two parts water and one part soil 

All data were subjected to analysis of 

variance, and treatment means were evaluated with 

Duncan's new multiple range test (F = 0.05). 

Survival data were subjected to arc sine transformation. 

Results 

After 1 year, soil N, P, Mn, Zn, and Cu were 

significantly higher in sludge plots than in 

fertilized plots. Soil in fertilized plots'had 

slightly more K and Mg and a higher pH than in 

sludge plots. Ca and Mg were higher in soil in 

fertilized disked plots than in fertilized s~bsoiled plots. Organic matter and cation exchange 

capacity were unaffected by treatment (table 2). 

Several constituents of foliage were also 

affected by amendment. Trees grown in sludgeamended plots had higher foliar N, Mn, Ba and, 

on disked plots, Zn than on fertilized plots. 

Trees on fertilized plots had more K and Mg than 

on sludge plots. 

The effect of sewage sludge on growth after 

4 years was striking. Trees on these plots grew 

an average of 37 percent more in height and 76 

percent more in diameter at breast height (DBH) 

than trees grown on fertilized plots (table 3). 

Four-year survival was not influenced by treatment. 

Subsoiling interacted with amendments to produce different effects on tree growth. On 

fertilized plots, after 4 years trees grew 9 percent more in height and 17 percent more in diameter 

on plots subsoiled 46 cm deep than on plots subsoiled 92 cm deep. When sewage sludge was used, 

however, there was significantly more growth, i.e., 

4.5 percent more height and 7.4 percent more DBH 

when plots were subsoiled to a depth of 92 cm 

rather than 46 cm (table 4). No growth differences 

due to spacing of furrows or number of subsoiling 

directions could be detected after 4 years (table 

5). 

Seventh-year growth data (table 6) do not show 

the difference in growth due to subsoiling depth 

that was evident with fourth-year data. There is 

still an advantage, however, of subsoiling over 

disking, particularly on the sludge plots where 

height, diameter, and II2H are all significantly 

higher on subsoiled plots. On fertilized plots, 

subsoil.ing improved only height growth. 

ORANGEBURG SOIL EXPERIMENT 

Methods 

This experiment, installed on the Savannah 

River Forest Station, Aiken, SC, was replicated 

four times in a randomized complete block design. 

A split-split-plot design tested three fertility 

treatments and two mechanical site preparation 

treatments, i.e., subsoiled versus disked only. 

The species used was sweetgum (Liquidambar 

styraeiflua L.) with two mycorrhizal treatments, 

Zlomus spp. versus noninoculated. In an effort to 

control weeds, Simazine (Princep F-G) was applied 

(23 kg/ha) in May 1982 and later in the season an 

application of Roundup(3.7 R/ha as a 1 percent 

solution). In July 1983 sludge was applied to onethird of the plots at a rate of 34 Mg/ha. Following sludge application in July, all plots were 

double-disked and in September one-half of each 

block was subsoiled to a depth of 76 cm with 

furrows spaced at 122 cm. Furrows were made in 

only one direction creating parallel lines. 

After 2 years, growth data were taken, and 

soil samples were collected and analyzed. Data 

were subjected to analysis of variance and means 

separated by Duncan's new multiple range test. 

Results 

Survival, not affected by any treatment, 

ranged from 83 to 88 percent. After 2 years, 

growth was significantly greater in both sludge 

and fertilizer treatments than in nonfertilized 

control treatment (table 7). Height, root-collar 

diameter, and D'H on trees in subsoiled plots were 

significantly greater than on trees in nonsubsoiled 

plots. 

DISCUSSION 

Most severely eroded sites, like those common 

in the Georgia Piedmont or sites otherwise devastated, such as borrow pits, require some mechanical 

site preparation and the addition of organic or 

inorganic amendments before they can be effectively 

reforested. On many such sites, even planting of 

seedlings is difficult unless the soil has been 

loosened in some manner. Subsoiling or ripping 

improves water penetration and internal structure 

of many soils and facilitates planting, whether by 

machine or hand. 
Table 3.--Influence of amendment on grow;? of loblolly pine on a barrow pit after 4 yearsTreatment Survival Height DBN 

Percent - cm - rrmf 

/ Fertili er- c 4 98.4a 261.2b 24.3b 

Sludge- 98.8a 358.5a 42.9a 

% increase due 

to sludge 

Treatment means within a column followed by the 

same letter do not differ significantly at P=0.05, 

1,121 kg/ha 10-10-10 fertilizer and 2,242 kg/ha 

pulverized dolomitic limestone. 

Table 4.--Influence of subsoiling depth on growth 

of loblolly pine on a bor ow pit with different 

amendments after 4 years- a 7 

Subsoiling 

Treatment depth DBM 

- en - cm - mrt 

b / Fertilizer- 92 245.8b 23.2'0 

6 278.6a 27. la 

% change with 

increasing depth -9.3 -16.8 

~lud~e~' 92 375. 4x 46.0~ 

46 359.1 y 42.8~ 

% change with 

increasing depth i-4.5 -t-7 . 4 

a/ Treatment means within a column followed by the 

same letter do not differ significantly at P=0.05. 

b/ 1,121 kg/ha 10-10-10 fertilizer and 2,242 kg/ha 

pulverized dolomitic limestone. 

Table 5.--Influence of subso'ling on growth of loblolly pines in 

amended plots after 4 years2 4 

Subsoiling intensity 

Spacing c / Fertilizer- d / 

Number of b/ between Depth of Sludgedirections- furrows furrows Height DBH Height DBH 

- cm - cm - cm - mm - cm - mm 

2 D 220 4 6 303a 31.4~1 355a 42.6b 

1 D 220 4 6 277ab 26.2abc 353a 43.4ab 

20 110 4 6 275ab 27.2ab 358a 43.4ab 

ID 110 46 259abc 23.6abcd 371a 43.5ab 

Disking 15 em deep 21 7c 17.3d 288b 30.5~ 

d/ Treatment means within a column followed by the same letter do not 

differ significantly at P = 0.05. 

b/ ID = all furrows running in rhe same direction and parallel; ZD - 

furrows running in two directions creating a square grid pattern, 

c i - 1,121 kg/ha 10-10-10 fertilizer and 2,242 kg!ha pulverized 

dolomitic limestone. 
The three studies summarized in this paper 

show that subsoiling can produce greater early 

growth of trees. Subsoiling produced good results on Madison soil in spite of the fact that 

the subsoiling was done just before planting in 

late winter when the soil was moist. The preferred time to subsoil is late smmer or early 

fall when soil is dry. Fall ripping in dry soil 

produces better fracturing and allows ample time 

for siltation of furrows to occur before planting 

in the furrows. 

The borrow pit study demonstrates the high 

value of sewage sludge amendments for stimulating 

good growth of loblolly pine even on the worst of 

sites. The rate of application of inorganic 

fertilizer used in this study did not supply 

macronutrients in amounts equivalent to that given 

sludge plots. The rate was high, however, for a 

single application on a reforestation site. 

Application of fertilizer at a higher rate would 

have been impractical, since much of it would have 

been lost by leaching or washing before it could 

have been utilized. Split applications of fertilizer are usually an impractical approach for 

forest regeneration or reclamation. In other 

research on devastated sites reported earlier 

(Berry 1982; Berry and Marx 1980), trees growing 

on plots amended with sewage sludge are maintaining 

rapid growth at this time (10th year) with no 

indication of slowing down, whereas trees on 

fertilizer plots are barely surviving. 

Less growth of trees during the first 4 >ears 

on fertilizer plots with deep subsoiling (table 

4) demonstrates the potential for leaching of 

nutrients in inorganic fertilizer compared with 

the organically bound nutrients in sewage sludge. 

Sludge produced more growth on plots that had 

received the deeper subsoiling. With both amendments, any intensity of subsoiling produced better 

growth than just disking (table 5). It was 

obvious that this response was due to deep root 

penetration. Four of the eight subsoilingintensity treatments on fertilizer plots produced 

significantly more growth than disking only, but 

on sludge plots, all subsoiling treatments produced tree growth significantly better than on 

disk-only plots. 

Root systems of several trees were excavated 

after 2 years. In all cases, root penetration 

was as deep as the depth of the tillage by disking 

or subsoiling; 15 to 20 cm on disked plots, 46 

cm on plots subsoiled to that depth, and 92 cm 

on plots subsoiled to that depth. On borrow pits 

that had not been subsoiled, there has been 

practically no root penetration deeper than a few 

centimeters, even after 25 years. Good root 

~enetration is important not only for nutrient 

and water relations but also to allow trees to 

anchor themselves for support. 

The main benefits of subsoiling are reduction 

in bulk density and soil hardness, and in improvements in moisture relations and root penetration 

which in turn improves uptake of moisture and 

nutrients and allows better anchorage. Since 

inorganic fertilizer is lost so rapidly when deep 

subsoiling is employed, the high cost of hauling 

sludge becomes more acceptable. 

Although analysis did not reveal much difference in growth rate of pine due co intensity of 

subsoiling in the borrow pit experiment, it should 

be remembered that the trees are still young and 

differences may develop, particularly in resistance 

to windthrow at an older age. Until more information for treatment of denuded sites is available, 

a good recommendation would be to use a generolls 

application of amendment, sewage sludge if possible, 

where economics are favorable; incorporate the 

amendment thoroughly, and subsoil with parellel 

furrows on ttte contour with a spacing as needed 

for the species to be planted. Seedlings should 

be planted in the furrows. Subsoil as deep as 

mechanically possible if sludge has been applied, 

but not so deep - probably no nore than 50 cm - if fertilizer is to be used. 

Timing is also important and should ideally 

be in the following sequence: (1) application of 

arnendment--prior to incorporation, (2) incorporation of amendment--prior to subsoiling, (3) 

subsoil in August or September, (4) plant in 

February. Subsoiling is most effective when the 

ground is dry and therefore should be planned for 

August or September. As much time as possible, 

up to 6 months, should elapse between subsoiling 

and planting to allow furrows to close naturally 

without compaction. 

Planting good quality, heavily mycorrhizal 

seedlings after following the above procedure 

should virtually assure the rapid establishment of 

a healthy rapidly growing stand, even on a site as 

adverse as a borrow pit. 

These studies were carried out in cooperation 

with the U.S. Department of Energy under Contract 

No. DE-A109-SRO-870 and with the Catawba Timber 

Co., Elberton, GA, 

Chemical analysis of foliage and soil was 

performed by Carol G. Wells, U.S. Department of 

Agriculture, Forest Service, Southeastern Forest 

Experiment Station, Forestry Sciences Zaboratory, 

Research Triangle Park, NC. 

The study on Orangeburg soil shows that even 

on a good site, gains in early growth can be made 

by subsoiling. It also shows the value of sewage 

sludge as Bn amendment on a good site. This is 

important since future disposal of sludge on land 

will be less expensive if it is not mandatory to 

be highly selective in choosing sites. 
Table 6,--Influence of subsoiling on growth of loblolly pine on a 

borrow pit amended with sewage sludge or fertilizer after 7 yearss/ 

Subsoiling 

depth Survival Height Diameter D~R 

Percent -- - em - mm cm3 x 10' 

 FERTILIZER^^ 

~antrol~' 96. 0ab 361b 52a 14.5b 

46 (4 treatments) 98.2a 4 30a 66a 22.7a 

92 (4 treatments) 97.2a 413a 61a 19.5ab - 

X (9 treatments) 97.5A 4 15B 62B 20.4B 

c / Control- 97.6a 594b 94b 58.0b 

46 (4 treatments) 97.4a 662a 108a 82.9a 

92 (4 treatments) 97.8a 681a llla 90.9a - 

X (9 treatments) 97.6A 663A 108A 83.7A 

1/ Means within a column followed by the same lowercase or uppercase 

letter do not differ significantly at P = 0.05. 

b' 1,121 kg/ha of 10-10-10 fertilizer plus 2,242 kg/ha of dolomitic 

limestone. 

C/ Disk only, approximately 15 cm in depth. 

17 Mg/ha. 

Table 7.--Growth of sweetgum on a good forest site with Orangeburg a / soil- 

- 

Treatment Survival Height Diameter D~H 

Percent - cm - mm -- cmS x 10' 

MINOR PLOTS 

Control 85a 123b 28b 

83a 144a 36a 

88a 155a 37a 

MAJOR PLOTS 

Subsoiled 88a 147a 36a 

Not subsoiled 83a 134b 31b 

a/ Means within a column followed by the same letter do not differ 

significantly at P = 0.05. 

b/ 280 kg/ha of diamnonium phosphate. 

LITERATURE CITED 

Berry, Charles R, Initial response of pine seedlings 

and weeds to dried sewage sludge in rehabilitation 

of an eroded forest site. Res. Note SE-249. 

Asheville, NC: U.S, Department of Agriculture, 

Forest Service, Soltheastern Forest Experiment 

Station; 1977. 8 pp. 

Berry, Charles R. Slit application of fertilizer 

tablets and sewage sludge improve initial growth 

of loblolly pine seedlings in the Tennessee Copper 

Basin. Reclamation Review 2:33-38; 1979a. 

Berry, Charles R. Subsoiling improves growth of pine 

on a Georgia Piedmont site. Res. Note SE-284. 

Asheville, NC: U.S. Department of Agriculture, 

Forest Service, Southeastern Forest Experiment 

Station; 1979b. 3 pp. 

Berry, Charles R. Dried sewage sludge improves 

growth of pines in the Tennessee Copper Basin. 

Reclamation and Revegetation Research 1:195-201; 

1982. 
Berry, Charles R, Growth response of four hardwood 

tree species to spot fertilization by nutrient 

tablets in the Tennessee Copper Basin. RecLamation and Revegetation Research 2: 167-175; 1983. 

Berry, Charles R. Reclamation of severely devastated 

sites with dried sewage sludge in the Southeast. 

In: Cole, Dale W.; Henry, Charles L.; Nutter, 

Wade L., eds. The Forest alternative for treatment and utilization of municipal and industrial 

wastes. Proceedings, Forest land applications 

symposium, 1985 June 25-28, Seattle, WA. 

Seattle: University of Washington Press; 1986: 

497-507. 

Berry, C.R. Subsoiling and sewage sludge aid loblolly pine establishment on adverse sites. 

Reclamation and Revegetation Research 3:301-311; 

1985. 

Berry, Charles R.; Marx, Donald K. Effects of 

PisoZithus tinetorius ectomycorrhizae on growth 

of loblolly and Virginia pines in the Tennessee 

Copper Basin. Res. Note SE-264. Asheville, NC: 

U.S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1978. 

6 PP. 

Berry, Charles R.; Marx, Donald H. Significance 

of various soil amendments to borrow pit reclamation with loblolly pine and fescue. 

Reclamation Review 3387-9h; 1980. 

Guild, D. W. Windrowing and ripping, a comparative 

study with other site preparation techniques. 

New Zealand Journal of Forestry 16:88-97; 1971. 

Hatchell, G.E.; Berry, C.R.; Muse, H.D. Nondestructive indices related to aboveground biomass 

of young loblolly and sand pines on ectomycorrhizal and fertilizer plots. Forest Science 

31 :419-427; 1985. 

Kormanik, Paul P.; Schultz, Richard C. Significance 

of sewage sludge amendments to borrow pit reclamation with sweetgum and fescue. Res. Note SE329. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest 

Experiment Station; 1985. 7 pp. 

Moehring, D. M. Forest soil improvement through 

cultivation. Journal of Forestry 68:328-331; 

1970. 

Page, Ian. Deep ripping, some hints from the U.K. 

Forest Industries Review, Rotorua, Kew Zealand 

33:30-32; 1977aPage, Ian. Improving the efficiency of ripping. 

Forest Industries Review, Rotorua, Yew Zealand 

39:28-32; 1977b, 

Schroder, D. Ruswirkungen von lockerungsrnanahwen 

auf das Bodengefege von Pseudogleyen. Zeitschrift 

fur Pflanzenernahrung und Bodenkunde 2:197-208; 

1975. 

Wilson, H.H. Land preparation ripping. In: 

Proceedings, spposiun! on land preparation for 

forestry in New Zealand; 1969 March; Kelson, 

New Zealand. 11:59-60; 1969. 

Ruehle, John L, Growth of containerized loblolly 

pine with specific ectomycorrhizae after 2 years 

on an amended borrow pit. Reclamation Review 

3:95-101; 1980. 
Effect of Site Preparation Soil Movement on Loblolly Pine Height Growth in 

12-and 14-Year-Old Plantations in the Hilly Coastal Plain of ~labamal~ 

Michael S. Golden and Christopher Y. Isaacsonz' 

Abstract--The major objective of this study was to determine whether 

soil movement from rake-and-pile site preparation has affected height 

growth of loblolly pine (Pinus taeda L.) plantations in the Hilly Coastal 

Plain. Soil, topographic, and tree data were taken from 80 tenth-acre 

sample plots. Stem analysis was performed on one dominant or codominant 

tree in 60 of the sample plots. Measurements were classified as from 

windrow, between-windrow, or scalped areas, reflecting the surface soil 

impacts of the site preparation treatment. Soil bulk densities were 

higher on the scalped areas, although not severe (1.33 and 1.36 g/cc for 

the 12-and 14-year-old stands, respectively). Average soil organic 

matter content was lower and E-horizon depth was less on the scalped than 

on the between-windrow plots. Although significantly different at the 10 

percent level, the trees growing in windrow areas averaged only about one 

foot taller than between-windrow trees in the 14-year old stand. Tree 

heights averaged 8.1 and 5.8 ft shorter on the scalped areas than on the 

bstween-windrow areas for the 12-and 14-year old stands, respectively. 

Heights indicated 17.9 and 10.7 ft lower site indexes on the scalped 

nlots for the 12-and 14-year-old stands, respectively. 

INTRODUCTION 

Methods of mechanical forest site preparation 

for planting vary, but one of the more common 

approaches utilizes some combination of 

shearing, rootraking or bulldozing, and piling. 

Although mechanical site preparation in many 

cases facilitates planting, increases survival 

(campbell 1973, Grelen 1959, Hebb 1957, Hu et 

al. 1980), and may give an early height 

advantage to young pines (Burns 1973, Derr and 

Mann 1970, Hebb 1957, McMinn 1969, Worst 1964), 

concern has grown that long term site 

productivity may be reduced following some 

applications (Brendemuehl 1967, Burns and Hebb 

1972). Site preparation techniques which may 

displace topsoil, Buch as bulldozing, shearing, 

rootraking or piling, are of greatest concern 

ro lass 1976, Haines et al. 1975). 

This study was designed to document 

variations in existing loblolly pine (pinus 

- taeda L.) plantations which may be due to 

topsoil displacement or other changes which 

occurred during the site preparation process. 

1' Paper presented at Southern Silvicul tural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2' Associate Professor, School of Forestry, 

Alabama Agricultural Experiment Station, Auburn 

University, AL 36849; and Area Forester, 

MacNillan Bloedel, Inc., Marion, AL 36756. 

METHODS 

Study Areas 

After considerable reconnaissance, two large 

loblolly pine plantations were located which 

had been site prepared by rootraking and 

piling and were among the oldest available 

which were suitable. They were located in 

Butler County, Alabama, on the Hilly Coastal 

Plain (~odgkins et al. 1979). At the time of 

data collection, one plantation was 14 and the 

other 12-years-old from planting. 

Topography was level to rolling on both 

sites. Slope percentages ranged from 0-28 

percent at the 14-year-old and from 1-14 

percent at the 12-year-old stand. The three 

prevalent soil series found were Smithdale, 

Luverne, and Boswell, with Smithdale most 

common. Smithdale soils are fine-loamy 

siliceoues, thermic Typic Paleudults, 

typically with sandy loam E horizons and thick 

Bt horizons that are sandy clay loam in the 

upper part and sandy loam in the lower part. 

They are well-drained, with moderate 

permeability. Luverne soils are clayey, 

mixed, thermic Typic Hapudults with sandy loam 

E horizons and clay loam to clay Bt horizons. 

They are well-drained and moderately slowly 

permeable. Boswell soils are fine, mixed, 

thermic Vertic Paleudalfs with thin, fine 

sandy loam E horizons and clay Bt horizons. 

They are moderately we1 l-drained , but with 

very slow permeability. Additionally, small 

areas of alluvial soils were associated with 

minor drainages. 

The plantation sites had been prepared by 

shearing and rootraking, with the debris piled 
in short, discontinuous windrows, The native 

stand before harvest and treatment had been 

mature second growth loblolly pine with a 

well-developed hardwood understory. 

Data Collection and halysis 

Data were collected from 80 tenth-acre 

circular plots, with 64 and 16 taken in the 14 

and 12-year-old plantations, respectively. 

They were placed using a modified random 

scheme, where the sites were stratified by 

topographic classes, Distribution among the 

topographic strata was as follows: 

Topographic Class Slope pct No. of plots 

Ridge 0-2 12 

sw :lope 3-1 0 28 

ME slope 3-1 0 8 

ME slope 10-20 24 

Alluvial 0-2 8 

Within each plot, the ground surface was 

delineated into "windrow", "non-windrow" , and 

"scalpedw areas based on evidence such as soil 

piles, depressions, bare exposed subsoil, and 

ground vegetation, Plots originally located 

such that a substantial portion was in a 

scalped area were shifted so that the plot was 

centered as much as possible in the scalped 

zone in order to achieve a relatively 

homogenous condition within the plot. As a 

result 4 plots in the 14-year-old stand and 3 

in the 12-year-old stand were classified as 

wscalped". 

Diameter of each tree was measured with a 

tape at breast height, The total height of 

each sixth tree wa? measured with a height 

pole. Each tree was designated as tfwindrow" or 

"between-windrow" based on its proximity to 

apparent windrow remains. A tree whose crown 

area, projected to the ground, came in contact 

with a windrow was classified as a "windrow" 

tree. 

A modified form of stem analysis was 

conducted on one dominant or codominant tree 

from 44 plots in the 14-year-old stand and all 

16 plots of the 12-year-old stand. A tree 

selected for analysis was felled by cutting at 

ground level. Each yearts height growth was 

delineated by interpreting growth flushes, 

beginning at the tip and working back toward 

the butt. Although loblolly pine has a 

variable number of height growth flushes each 

year (typically 3 or 4), each season's flushes 

usually occur in a readily recognizable 

pattern. The first flush will normally be the 

longest of the season, and the beginning of 

this flush will usually be marked by a 

relatively large, persistent limb whorl. 

Subsequent flushes will be progressively 

shorter and the associated limb whorls smaller 

and less persistent. Thus the tip location at 

the end of each growing season is indicated by 

a whorl of relatively larger limbs preceded by 

a short internode and followed by a long one, 

with succeeding shorter ones. This recurring 

pattern is most visible in younger trees, and 

has been used to provide a more precise 

reconstruction of yearly tip heights than is 

possible with conventional stem analysis 

(Wakeley and Plarrero 1958, Trousdell et al. 

1974). 

Soil profiles were examined and samples for 

laboratory analysis were taken using a bucket 

auger, Where windrows or scalped areas 

occupied less than 15 percent of the plot, 

three profile samples were taken to a depth of 

22 inches. However, when such conditions 

occupied more than 15 percent of the plot, two 

samples were taken from the windrows or 

scalped areas and two from the rest of the 

plot. Four bulk density samples were taken 

from the surface 3 inches of each plot with a 

3 inch diameter ring and analyzed using the 

core method described by Blake (1965). Due to 

difficulty with voids and incorporated organic 

matter, the bulk density samples from windrows 

were not used. 

Soil profile samples were air dried, ground, 

and passed through a 2 mm sieve. Soil texture 

was determined using the Bouyoucos hydrometer 

method (~ay 1965). Soil pH was measured using 

a 1 :I soil-water mix (~eech 1965). Soil 

organic matter was determined by the 

Walkley-Black method (~ackson 1958). 

Plot characteristics means for the windrow 

and between-windrow (scalped areas excluded) 

areas were compared for each stand using an 

overall t-test and a paired t-test procedure 

(~teele and Torrie 1960, Draper and Smith 

1966). On each plot, a tree height plot mean 

was determined for a class whenever two or 

more trees of the class were present. A 

significance level of 10 percent was used, due 

to high variability in the data. 

RESULTS AND DISCUSSION 

Table 1 presents a comparison of the soil 

characteristics and non-pine vegetation means 

which differed significantly (10 percent 

level) across condition classes within a 

stand, The profile textures and pH's were not 

different. 

Soil organic matter and E horizon thickness 

show clearly the results of removing topsoil. 

from the scalped areas and of pushing topsoil 

into the windrows. Values are considerably 

higher in the windrows and somewhat lower in 

the scalped areas. The E horizons of the 

windrows are actually conglomerations of 

materials which were pushed into the windrow 

piles. Thus they may consist of mixtures of 

E, B, and even C horizon materials, as well as 

organic debris. 
TABLE 1.--Plot averages Mean tree heights for significant soil 

and vegetation characteristics of the two 

plantations 

Soi 1 Soil E Non-Pine 

Bulk Organig Horizon Woody 

Plantation Densitya Matter Thickness Plants 

+ (g/cc) (pct) (in,) (ftL/A) 

I +year 

Betweenwindrow 1.20 1.63 11.0 5.58 

Scalped 1.36 1.05 8.8 3-95 

Windrow --- 2.05 23.1 -- 

12-year 

Betweenwindrow 1.27 1.45 8.6 4.88 

Scalped 1.33 0.93 7.4 2 . 47 

Windrow --- 2.32 25.8 -- 

:surface 3 inches. 

Top 22 inches. 

Soil bulk density comparisons of the surface 

3 inches of the scalped and between-windrow 

areas reflect the residual effects of 

compaction during the mechanical treatment and 

perhaps by subsequent raindrop action on the 

persistent bare soil of the scalped areas. 

Although the scalped area bulk densities of 

1.36 and 1.33 g/cc in the 14 and 12-year 

stands, respectively, are not extreme, they do 

reach or exceed the 1.33 g/cc level found by 

Foil and Ralston (1967) to severely restrict 

loblolly pine root growth on loamy sand Coastal 

Plain soils. Some recovery from compaction 

should have occurred since treatment through 

the action of plant roots and soil organisms, 

so the immediate post-site preparation bulk 

densities must have been higher. 

The scalped areas are particularly 

conspicuous due to their much more open 

appearance compared to the surrounding area of 

each plantation. The basal areas of the 

non-pine woody understories reflect this, being 

considerably lower on the scalped areas. Some 

understory species differences were also 

apparent. Shrubs of the genus Vaccinium were 

more prevalent on the scalped areas than 

elsewhere, and grasses were more abundant as 

well, 

Although the average tree heights were 

significantly taller in the windrows than in 

the be tween-windrow areas, the difference 

averaged only 1.0 ft. Part of the reason for 

this unexpectedly small difference is probably 

the difficulty in defining the extent and 

influence of the windrows. The windrows 

encountered on these sites were commonly not 

straight or even Linear. They sometimes 

occurred as disconnected piles, and their 

boundaries were not distinct, 

Tree height differences between the scalped 

and between-windrow trees were much more 

distinct, as shown below: 

Age 14 plots Age 12 plots 

fftf . , 

Non-scalped 41 .lr 38.4 

Scalped 35.3 30.3 ---- ----- Difference 5 8 8.1 

These height differences were significant, and 

clearly indicate the potential reduction in 

productivity that is possible where extremes 

of improper treatment occur. Figures 1 and 2, 

developed from the stem analysis data, 

illustrate that the divergence between scalped 

and between-windrow tree heights developed 

early and was continuing at the last ages 

measured. 

Figure ?.--Average dominant pine height growth 

curves for between-windrow and scalped plots 

in the 14-year-old plants tion. 

Figure 2.--Average dominant pine height growth 

curves for between-windrow and scalped plots 

in the 12-year-old plantation, 

Site index differences between the scalped 

and be tween-windrow stands are even more 

striking. Estimated 25-year site indexes 

based on the heights measured (Amateis and 

Burkhart 1985) are : 
Site index (25-year) 

14-year stand 42-year stand 

(ft) ( f t) 

Ek tween-windrow 67.2 73.5 

Scalped - 56.5 - 55.6 

Difference 10,7 17.9 

Diameter differences, although significant, 

were less striking. Average dbh for the 

between-windrow and scalped areas in the 

14-year plantation was 5.9 and 5.3 inches, 

respectively. Possibly the reduced competition 

on the scalped plots contributed to the 

diameter growth differences being less 

spectacular than those for height. 

These scalped areas represent the extreme of 

treatment conditions. Of the 80 plots randomly 

placed, 7 (8.8 percent) were in scalped areas. 

Although this may not be considered a good 

estimate of the total plantation area in a 

scalped condition, it does not seem 

unreasonable. Personal observation indicates 

that most recent rake-and-pile site treatments 

result in less of such severe conditions. 

Avoiding such severe scalping of topsoil seems 

to be primarily dependent upon machine operator 

care and skill. 

LITERATURE CITED 

Amateis, Ralph L.; Burkhart, Harold E. Site 

index curves for loblolly pine plantations on 

cutover site-prepared lands. Southern Journal 

of Applied Forestry 9(3) : 166-1 69; 1985. 

Blake, G.R. Particle density. In: Black, C.A., 

ed. Methods of soil analysis, part 1. 

Madison, WI: American Society of Agronomy, 

Inc . ; 1965 : 374-391 . Brendemuhl, R.H. Loss of topsoil slows slash 

pine seedling growth in Florida Sandhills. 

Res. Note SO-53. New Orleans, LA: U.S 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1967. 4 

PP 

Burns, R.M. Economical site preparation for 

pine in the,Sandhills. Tree Planter's Notes 

24(2):25-28; 1973. 

Burns, R.M.; Hebb, E.A. Site preparation and 

reforestation of droughty, acid sands. 

Agriculture Handbook 426. Washington, DC: 

U.S. Department of Agriculture; 1972. 61 pp. 

Campbell, Robert G. The impact of timber 

harvesting and site preparation on selected 

soil conditions and plant growth. Athens, GA: 

University of Georgia; 1973. 65 pp. 

Dissertation. 

Day, P.R. Particles fractionation and particle 

size analysis. In: Black, C.A., ed. Methods 

of soil analysis, part 1. Madison, HI: 

American Society of Agronomy, Inc.; 

1965 : 545-567 

Derr, H.J.; Mann,W.F. Site preparation 

improves growth of planted pines. Res. Note 

SO-106. New Orleans, LA: U.S. Department of 

Agriculture , Forest Service, Southern Forest 

Experiment Station; 1970. 3 pp. 

Draper, NOR,; Smith, H. Applied regression 

analysis. New York: John Hiley and Sons, 

Inc; 1966. 481 pp. 

Foil, R.R.; Ralston, C.W. The establishment 

and growth of loblolly pine seedlings on 

compacted soils, In: Proceedings, Soil 

Science Society of America 31:565-568; 1967. 

Glass, G.G. The effects from rootraking on an 

upland Piedmont loblolly pine (pinus taeda 

L.) site. Technical Report No. maleigh, 

NC: School of Forest Resources, North 

Carolina State University; 1976. 44 pp. 

Grelen, H.E. Mechanical preparation of pine 

planting sites in Florida Sandhills. Weeds 

7:184-188; 1959. 

Haines, W.L.; Maki, T.E.; Sanderford, S.G. The 

effect of mechanical site preparation 

treatments on soil productivity and tree 

(Pinus taeda L. and P, elliottii Ehgelm.) 

growth, In: Bernier, B.; Winget, C.H., eds. 

Forest soils and forest land management. 

Quebec: Lave1 University Press; 

1975:379-395. 

Hebb, E.A. Regeneration in the Sandhills. 

Journal of Forestry 53:21-212; 1957 

Hodgkins, Earl J.; Golden, Michael S.; Miller, 

W. Frank. Forest habitat regions and types 

on a photomorphic-physiographic basis: a 

guide to forest site classification in 

Alabama- Mississippi. Cooperative Series No. 

210. Auburn, AL: Alabama Agricultural 

Experiment Station, Auburn University; 1979. 

64 PP* 

Hu, Shih-Chang; Pitthavong, V. The effects of 

site preparation on growth of loblolly pine 

in southeastern Louisiana. In: Barnett, 

J.P., ed. Proceedings, first biennial 

southern silvicultural research conference. 

General Technical Report SO-34. New Orleans, 

LA: U.S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1980:92-95. 

Jackson, M.L. Soil chemical analysis. 

Englewood Cliffs, NJ: Prentice-Hall, Inc.; 

1958. 493 PP* 

McMinn, James W. Preparing sites for pine 

plantings in south Florida. Res. Note 

SE-117. Asheville, NC: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1969. 5 pp. 

Peech, M. Hydrogen-ion activity. In: Black, 

C.A., ed. Methods of soil analysis, paft 2. 

Madison, WI: American Society of Agronomy, 

Inc . ; 1965 : 91 4-926. 
Steele, G.D.; Torrie, J.H. Principles and 

procedures of statistics, New York: 

McGraw-Hill Book Co., Inc.; 1950. 481 pp. 

Trousdell, K.B.; Beck, D.E.; Lloyd, F.T. Site 

index for loblolly pine in the Atlantic 

Coastal Plain of the Carolinas and Virginia. 

Res. Paper SE-115. Asheville, NC: U.S. 

Departraent of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1974. 

PP* 

Wakeley, P.C.; Marrero, 3. Five year intercept 

a s s i t e index in southern pine plantations, 

Journal of Forestry 56~732-336; 1958. 

Worst, R.H. A study of the effects of site 

preparation and spacing on planted slash 

pine in the coastal plains of southeast 

Georgia. Journal of Forestry 62:556-560; 

1 964 
10-YEAR OLD PLANTATION ATTRIBUTES AS AFFECTED BY HARVESTING AND SITE PREPAMTION NETHOD&/ 

2 / G. Kenneth XydiasAbstract.--Paired plots of approximately five acres in size were harvested in 

1975-76 by either a whole tree or by a stemwood harvest at six locations in 

Virginia and two locations in Georgia, These areas were then prepared either 

by chopping and burning or by harrowing, and then planted. Harvesting method 

had little effect upon stand attributes at age 10 at those locations prepared 

by chopping and burning. Whole tree harvest areas that were harrowed had 

taller trees, more trees, more pine basal area, and less hardwood basal area 

than the cornpanion plot that was harrowed following stemwood harvest. A 

possible explanation for this is that the whole tree harvest removed enough 

of what would have been logging debris to permit the harrowing operation to be 

more effective. 

The growth and yield of planted stands is a complex process, and is one affected by many interrelated factors. bfaj or ones include the inherent 

potential of the site to provide both water and 

nutrients, pine stocking and the extent to which 

competing vegetation is controlled. 

Coile (1355) in his classic revjew of soil factors affecting site index, concluded that soil 

factors affecting water supply such as texture 

and depth to horizons limiting root penetration 

were of paramount importance. More recent work 

with region-wide studies installed on a wide 

variety of sites by members of the North Carolina 

State Tree Nutrition Cooperative have clearly 

shown that mid-rotation growth of loblolly pine 

(Pinus tadea L.) can be increased on most piedmont 

sites by an application of nitrogen (N), and either 

W or a combination of M and phosphorous (P) on 

coastal plain sites (Eallard, 1960). Control of 

herbaceous vegetation shortly after planting has 

increased early growth rates (Creighton and 

Zutter 1985), and this increase has been shown to 

persist for many years (Creighton et al. 1955, 

Schmidtling, 1984). Control of understory and 

mid-story woody stems has also increased the 

growth of the pine overstory (Rheny et al. 1986), 

and so has pine release lover and Dickens, 1985). 

A preliminary attempt has been made to model the 

influence of competing hardwood on pine growth 

(Burkhart and Sprintz, 1954), and this suggests 

that its effect is substantial. 

A variety of site preparation techniques have been 

used to prepare a site for planting, and have been 

the subject 02 numerous studies and reviews 

(Broerman et al, 1983, Sarigumba 19C4, Burger and 

Kluender 1982), Gruthf ield and Martin (l 982) 

painted out that the purpose of site preparation 

are to 1) remove logging debris for increased 

plantability, 2) control competing vegetation, and 

3) improve the microsite. They recommended that 

methods be selected that meet more than one of 

these criteria. Site preparation methods can 

either promote or retard plantation growth depending upon the ability of a particular method to 

control competing vegetation, displace organic 

matter and topsoil, affect erosion, or influence 

soil properties (Pritchett and :Jells 1975). 

Harvesting method is thought ro have an effect 

upon the growth of the future stand through its 

effect on soil physical properties and upon the 

nutrient reserves of the site. !lore than half of 

the nutrients in the above-ground biomass of a 

thirty-year old stand of planted pine are in the 

crown, and this proportion increases as stand age 

declines. lihole-tree harves- remove significantly 

more nutrients from the site than do conventional 

stem-wood harvests where the crown is left in 

place. These relationships have been well documented and concern expressed for the growth of 

future stands (Pritchett and lJells 1978). Whole 

tree harvests have also been viewed as a site 

preparation method by XcXinn (1982), although 

experience has generally shown that planting sites 

harvested in this manner without some attempt to 

control hardwood resprouts are likely to result 

in a poor pine stand. 

The efficacy of any particular method of site 

preparation in meeting the criteria outline by 

Cruthf ield and Mart in (1922) is undoubtedly 

influenced by both the method used and by the 

amount and type of debris left after harvest. 

This is influenced by both the nature of the 

stand being harvested and the degree of utilization of that harvest. Few if any researchers 

have examined the effect of these factors on pine 

stand establishment and growth. This paper will 

report on how the factors of prior stand characteristics, harvesting method, and site preparation 

method have affected the early development of 

planted Lobiolly pine (Pinus tadea L. j 

Paired plots of 5-10 acres in size were estab- 

'Paper presented at the Fourth Biennial Southern lished in each of eight stands in Georgia and Silvicultural Research Conference Govember 4-6, Virginia in 1974. A hundred percent tally o" all 1986. merchantable trees was done prior to harvest. 

'Division Research Forester, Continental Forest 

Investments, Sox 8969, Savannah, CA 31412. 

Plot pairs were then harvested by either a 'stemwood harvesting system or by a whole tree harvesting 
system. Each plot was then prepared using techniques deemed appropriate Eor the amount of logging 

residuals. Study location and site descriptions 

are given in Table 1, while preharvest volumes 

and methods of site preparation are summarized in 

Table 2. 

Preparation was done in the spring and summer of 

1975, and planting was done during the 1975/76 

dormant season. Seven twentieth-acre subplots 

were randomly established in each of the plot 

pairs, permanently monumented, and used to estimate planting and survival rates. These subplots 

were revisited following the second growing season 

to evaluate pine stocking and average height. 

110 further work was done until the dormant season of 1985186 when 4-5 permanent plot pairs were 

established 75-100 feet on either side of the line 

separating the two harvesting methods. fnfarnatio, ,dthcred 3t e,ch p:, il~,l1rded pinc basal 

area, hcight of Jominants, and number of trees, 

and hardwood basal area. Pine basal area was 

estimated with a EAF 5 prism held over the plot 

center. 3eight of dominants was based on the 

average height of three of the taller trees in 

the vicinity of the plot center. Pine treeslacre 

were estimated frox a twentieth acre subplot. 

IIardwood basal area was determined from three 

BAF 5 subp1ots located at the ends and center of 

a 30 foot transect centered on the plot center and 

oriented at right angles to the rows of planted 

pine. Stand attributes were tested for significant differences 11sing Student's T-test calculated 

for a paired plot analysis, except at the Dye 

tract where plots were not paired. 

Table 1.--Study locations and site description 

Tract - ~ra inag ea Region . CO!EGx__ State b 

Cannon 

Cobb 

Dye 

Bayes 

Miller 

Oschner 

Saunders 

Sou. Plant 

UCP 

P 

UCP 

P 

UCP 

UCP 

P 

P 

Burke G A 

Amelia V A 

Jefferson C A 

lfec klenburg V A 

Surry V A 

Surry V A 

Lunenburg Vh 

Amelia V A 

a~~~ drainage classes: SP = somewhat poorly, w = well, 

SE = somewhat excessive 

bRegions: UCP = upper coastal plain, P = piedmont 

Table 2.--Preharvest volumes and site preparation methods 

-------- Tract P ine Hardwood Stemwood lfJhole- tree 

----- Cords/Acre----- ------- Site Prqa -------- 

Cannon 

Cobb 

DY e 

Hayes 

Miller 

Oschner 

Saunders 

Sou. Plant 

a~ite prep methods: 13 = harrow, CB = chopiburn 

RESULTS AND DISCUSSION 

Planting rates, initial survival, and number of 

trees after the second growing season are given 

in Table 3. Survival for the 1976 planting season 

was excellent in the Georgia locations, but marginal in the Virginia locations except for the 

Saunders tract. Study sites on the Cobb and 

Southern Plantat ion tracts were replanted in the 

1977 planting season but stocking figures shown 

are prior to replanting. 
Table 3.--Planting rates, first year survival, and pine stocking at age 2 

Tract 11arves tc Planted Pct, Surv. Stocking 

Cannon 

cobba 

Dye 

Hayes 

Miller b 

Oschner 

Saunders 

SOU. planta 

bunable to distinguish planted trees from volunteers 

'~arvest: SW = stemwood, WT = whole tree 

Average height of the three tallest trees on 

each plot at age 2 is given in Table 4. Height 

differences were not significant at the five percent level for any of the sites with the exception 

of the Saunders tract. There, trees in the stem 

wood harvested plot were taller than trees in the 

whole tree harvest plot. 

Table 4.--Average heights of dominants after 

two growing seasons 

Tract Stem Wood Whole tree signif icaccea 

Cannon 

Cobb 

DY e Hayes 

?filler 

Oschner 

Saund ers 

Sou. Plant - 

Observation on both sides of the line separating 

the two harvest methods on the Rayes and Southern 

Plantation tracts suggested that large differences 

occurred. Both tracts had a reasonably well 

stocked pine stand in the whole tree harvest 

areas, and what is better described as a plantation failure or a stand that is more hardwood than 

pine in the area receiving a stemwood harvest. 

That perception is reinforced by both the stand 

attribute data of Table 5 and the probability 

associated with these differences shown in Table 

6. 

There appeared to be little visual differences 

-- - - -- in the plantation attributes at the other loca2.2 2.2 NS tions except for the Cobb tract, and that too is 

- - -- -- reinforced by the data of Tables 5-6. The lack 

3.5 3.7 N S of any difference for the Cobb tract may be due 

2.6 2.4 NS to an inadequate sample size. No plots were estab3.1 3.4 NS lished in either of the two location in Surry 

4.3 3-7 ., A County, VA, but observations at those sites sug- J- J 

2.9 2.8 NS gests that there were no differences. - - - - 

aN~ = not significant, *+< = significant at 0.01 

level 

Sardwood basal area were quite similar on both 

the Cannon and Dye tracts, and significantly 

greater in the conventionally logged plots on the 

other tracts. There were no observable differences ffeans for the various plantation attributes in 

1985 are given in Table 5, and probability asso- in hardwood basal area for the Surry County locaciated with the observed differences are given tions. 

in Table 6. At this point, we leave the factual 

realm, and enter into one of speculation. The 

questions of interest are: 1) are there any 

differences in planted stand attributes ten years 

after harvesting to different degrees of utilization, and 2) what is a reasonable explanation 

for those differences if they indeed exist. 
Table 5.--Plantation attributes in 1986 

----------------- Pine------------------ Sd~d 

Tract Age- Harvest EL- Dom.Ht. Trees DBE 9A 

Cannon L 0 SW 

WT 

Cobb 9 SlJ 

WT 

Dye lo SW 

IJT 

Hayes 1 0 SW 

Tsj T 

Saund er s 7 S1J 

WT 

Sou. Plant 9 SW 

WT 

Table 6. --Probability of observed differences in plantation attributes 

v- --- 

------------------ Pine ------------------- 11 d wd 

-- Tract BA - Dom. Ht. _____ Trees DBH B A 

Cannon 10 

Cobb N S 

D? e NS 

Iiayes 5 

Saunders 2 0 

Sou. Plant 5 

-- -- Probabilitiesare: KS 20.0, 20=10.0- 19.9, lo= 5.0- 9.9 

5 = 1.0 - 4.9, 1 = 1.0 

All of these observations may be reconciled by a Thus this treatment may have been similar to the 

hypothesis consisting of the following elements: chop/burn treatment on the Bayes tract. 

I) Plantation performance is dictated by site 

preparation efficacy for competition 

control. 

2) Site preparation efficacy is influenced by 

both the amount of residual debris and by 

the site preparation method. 

3) Residual debris is influenced by both the 

harvesting method and by the composition 

of the stand being harvested. 

The better'pine stand in the whole tree harvest 

plots on both the Hayes and Southern Plantation 

tracts could be due to more effective site preparation. The Hayes tract was pure hardwood, 

while the Southern Plantat ion contained equal 

volumes of hardwood and pine. The whole tree 

portion of the Hayes tract was prepared by harrowing and the sternwood harvested portion was 

prepared by a chop/burn treatment, A better job 

of hardwood control probably occurred on the whole 

tree portion of the Nayes tract. Both plots on 

the Southern Plantation tract were prepared by 

harrowing, However residual debris on the stemwood harvested plot could have been sufficient 

to prevent the harrow getting into the ground. 

No differences in pine or hardwood attributes 

were observed on the Cannon and Dye tracts. The 

only preparation method used here was a chopjburn 

treatment. Little hardwood was observed on the 

Cannon tract because it was essentially absent 

prior to harvest. The lack of hardwood is also 

reflected in the level of current hardwood basal 

area. The Dye tract had a pure hardwood stand 

prior to harvest and had an abundant amount of 

hardwood LO years after planting. The efficacy 

of a chopiburn treatment on hardwood root kill 

was not influenced by the amount of residual debris. 

Although no data was taken, there appeared to 

be little difference in pine or hardwood attributes 

on the Xiller and Oschner tracts. Both plots on 

these tracts were harrowed, but there was only a 

modest amount of hardwood in the prior stand 

(Table 2). This hardwood may not have been sufficient to interfere with the efficacy of harrowing. 

Results from the Cobb and Saunders tracts do not 

conform as well to the hypothesis. Both plots on 

the Cobb tract were harrowed, and there is considerably more hardwood basal area in the plot receiving the stemwood harvest. Plantation attributes generally do not differ significantly by 

harvest method, although the visual impression is 
one of superiority for the whole-tree plot, The 

sample size may have been too small to detect any 

difference. Alternatively, two-thirds of the 

volume prior to harvest was in pine, and the harrow 

treatment could have been equally effective for 

each harvest regime, 

Although the stemwood harvest plot on the 

Saunders tract now has significantly more hardwood 

basal area than the whole tree portion, there are 

no differences for the plantation attributes. That 

study area was reprepared by harrowing in the spring 

of 1979 when stocking in the remainder of the stand 

in which the study was located was judged to be 

unacceptable. Xuch of the residual debris from 

the stemwood harvested plots would have been 

partially decomposed by that time and would not 

have interfered with harrowing. If this is true, 

then the harrowing was equally effective for each 

harvest regime. 

Results from all locations seem to support the 

hypothesis that site preparation efficacy for 

hardwood competition control varies with site 

preparation method, harvest method, and composition of the prior stand. A major problem of this 

hypothesis is that it is not supported by measurements of residual debris after site preparation. 

However, the boundary between the two harvest 

methods can still be identified in the field by 

the presence of residual debris on those sites 

that were predominately hardwood stands prior to 

harvest , 

?fajor conclusions from this study are as follows: 

1) The potential performance of any planted 

stand is influenced by the composition of 

the prior stand, the method of harvest, 

and the method of site preparation, as 

well as soil characteristics of the 

particular sire. 

2) Although whole tree harvesting has the 

potential of site degradation through 

removal of the nutrient-rich crown, it 

can also result in a better stand than 

a stemwood harvest if it pennits use of a 

site preparation method that does a better 

job of hardwood competition control. 

3) Site preparation methods should be prescribed to meet the objectives of debris 

removal and competition control based on 

the conditions of each site. 

Ballard, R. Nitrogen fertilization of established 

loblolly pine stands: A flexible silvicultural 

technique. In: J. P. Barrett, ed. Proceedings 

of the first Southern Silvicultural Research 

Conference. Cen. Tech, Rept. SO-34, USDA For. 

Ser. New Orleans, LA; 1980. 223-229 pp. 

Burger, J, A,; Klunder, R. A. Site preparation-- 

Piedmont, In: R. C. Kellison and S. Gingrich, 

eds. Symposium on the loblolly pine ecosystem 

(East Region), School of For. Res., NC State 

Univ,, Raleigh, NC; 1982. 50-74 pp. 

Burkhart, W. E.; Sprinz, P. T. A model for assessing hardwood competition effects on yields of 

loblolly pine plantations. Pub. FWS-3-84, Sch, 

of For. & Wildlife Res. VPI and SU, Blacksburg, 

VA; 1984. 55 pp. 

Coile, T. S, Soil and the growth of forests. In: 

Advances in Agronomy; 1955. 

Creighton, J. L.; Zutter, B. R. The significance 

of weed control, treatment duration and application techniques as determinants of pine growth 

response. AUSHC note 85-18; 1985. 

Creighton, J. L.; Glover, G. R.; Zutter, B. R. 

Loblolly pine growth response to herbaceous 

weed control. A summary of 15 studies. Paper 

presented at 1986 Sou. \Teed. Sci. Soc. meeting; 

1986. 

Crutchfield, D. M.; Martin, J. P. In: R. 6. Kellison and S. Gingrich, eds. Symposium on the 

loblolly pine ecosystem (East Region). School 

of For. Res., North Carolina State Univ., 

Raleigh, TiC; 1982. 

Glover, G. R.; Dickens, D. F. Impact of competing 

vegetation on yield of the southern pines. GA 

For. Res. Paper 59, GA For. Corn. Macon, GA; 

1985. 

FlcMinn, J. I.?. Intensive whole tree harvesting as a 

site preparation technique. In: E. P. Jones, 

ed. Proceedings of the second biennial southern 

silvicultural research conference; Gen. Tech. 

Rept. SE-24, SE For. Expt. Sta. Ashville, NC; 

1982. 59-61 pp. 

Pritchett, W. L.; Wells, C. G. Harvesting and site 

preparation increase nutrient mobilization. In: 

T. Tippen, ed. Proc: A symposium of prin. of 

maintaining prod. on prepared sites, USDA For. 

Ser., New Orleans, LA; 1978. 98-110 pp. 

Rheny, J. I?. ; Shiver, B. D. ; Pienaar, L. V. 

PPIRC Competition Vegetation Study--Eight year 

results, 1976-84. PNRC Univ. of GA, Tech. 

Rept. 1986-2; 1986. 

Sarigumba, T. I. Sustained response of planted 

slash pine to spacing and site preparation. 

In: E. Shoulders, ed. Proceedings of the third 

biennial Southern Silvicultural Research Conf . Gen. Tech. Rept. 50-54, USDA For. Ser. Sou. For. 

Expt. Sta., New Orleans, LA; 1094. 79-84 pp. 

Schmidt1 ing, R. C. Early intensive culture affects 

long-term growth of loblolly pine trees. For. 

Sci. 30:2; 1984. 491-498 pp. 

Broerman, F. S.; T. I. Sarigumba; Immel, M. J. 

Site preparation and slash pine productivity. 

In: E. L. Stone, ed. The managed slash pine 

ecosystem. Sch. of For. Res., Univ. of Fla., 

Gainesville, FL; 1983. 131-149 pp. 
EFFECTS OF SITE PREPARATION, FERTILIZATION 

AND GENOTYPE ON LOBZOLLU PINE GROWTH M?D STAKD 

i 

STRUCTCW--ESfn;TS AT AGE 15 

L Marilyn A. Buford and Willim K. McKee, Jr. 

Abstract--Five site preparation treatments were imposed on 

a somewhat poorly drained area having loblolly pine site index 

of 70 feet (base age 25) on the Santee Experimental Forest in 

South Carolina: 1) control (no mechanical treatment), 2) v-blade, 

3) v-blade and rootrake, 4) v-blade, rootrake, and bed, and 5) 

v-blade, rootrake and disk. In February 1971, genetically improved and unimproved loblolly pine seedlings were planted at 

a density of 726 trees per acre. Four fertilizer treatments 

were tested: 1) control (no fertilizer), 2) 50 lbs P and 200 lbs 

N, 3) 100 lbs K and 200 lbs N, and 4) 50 lbs P plus 100 lbs K 

and 200 lbs N. Phosphorus applications increased mean tree 

heights and diameters through age 15, and application of 

nitrogen and potassium without phosphorus decreased them. There 

was a site preparation x genotype interaction in response to site 

preparation. 

Keywords: Pinus taeda, South Carolina 

INTRODUCTION 

Understanding the response of loblolly pine 

plantations of different genotypes to various site 

preparation treatments and fertilizer regimes is 

necessary for predicting yields of managed plantations. The study described here was designed to 

test the main effects and interactions of five 

site preparation treatments, four fertilization 

treatments, and two genotypes on the growth, survival, and yield of planted loblolly pine (Pinus 

- taeda L.). McKee and Wilhite (1986) reported some 

results of this and three similar studies through 

age ten. This report will describe the results at 

age 15. 

METHODS 

A somewhat poorly drained site (Wahee soil 

series, Aeric ochraquult, clayey, mixed, thernic) 

on the Santee Experimental Forest on the South 

Carolina Coastal Plain was chosen for the study, 

Before study installation, the site was burned, 

and merchantable timber was removed in the winter 

of 1968-1969. Unmerchantable timber was felled 

and left in place, and the area was burned again 

in February 1970. 

The experimental design is a split-split plot 

with main plots randomized in two complete blocks. 

Five site preparaiion treatments were applied on 

1-acre main plots, four fertilizer treatments were 

applied on 1/4-acre subplots, and seedlings of two 

genotypes were planted on 118-acre sub-subplots, 

The main plot treatments are: (1) control (no 

mechanical treatment), (2) v-blade, (3) v-blade 

and rootrake, (4) v-blade, rootrake and bed, and 

(5) v-blade, rootrake, and disk. The four subplot 

treatments are: (1) control (no fertilizer), (2) 

50 lbs P and 200 lbs M, (3) 100 lbs K and 200 lbs 

N, and 4) 50 lbs P + 100 lbs K and 200 lbs N. The 

levels of fertilizer were chosen after soil and 

foliar analysis during the first year after 

planting. The nitrogen was broadcast during the 

sixth growing season and all other fertilizer was 

applied during the second growingseasonbybroadcast.Responses to N and P are confounded and cannot be separated, 

The sub-subplot treatments were seedlings from 

two different seed sources: (1) seed production 

areas in natural stands in Colleton County, SC, 

and (2) seed orchards in Georgetown and 

erville Counties, SC. The site was planted by 

hand in February 1971 at a 6 x 10 foot spacing 

(726 trees per acre). The measurement plots are 

the interior 40 trees (4 rows of 10 trees) in each 

sub-subplot, There are two border rows between 

measurement sub-subplots and 4 border rows between 

masurement subplots. 

Presented at the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, GA, Hardwood competition was controlled by hand 

November 4-6, 1986, cutting and spraying the entire study area with 2, 

2 4, 5,-T in September 1970 and August 1972 to mainResearch Forester and Principal Soil Scientist, tain hardwood competition at the same level across 

Southeastern Forest Experiment Station, U, S. all treatments. This confounds the growth 

Department of Agriculture, Forest Service, response to site preparation, since an expected 

Charleston, SC 29407, 
result of more intensive mchanica2 site preparation is decreased hardwood competition, However, 

the removal of hardwood competition as a factor 

places the emphasis of early response to site preparation on soil disturbance, 

The following variables were calculated from the 

measurements made at ages 10 and 15 on each subsubplot: mean height, mean diameter (breast 

height), mean tree basal area, mean tree volume, 

total ,basal area, total volume and number of trees 

surviving. The volume equation used was: 

VOB - 0.0039557 (D" 8945)(~0' "" 1 

where D = diameter at breast height 

H = total height (Clutter et al. 1984). 

An analysis of variance to compare treatment 

effects on tree and stand parameters was performed 

for all the variables given above at ages 10 and 

15. F-statistics for the effects of interest were 

calculated. Basal area and total volume per acre 

were plotted by site preparation and fertilizer 

treatment for ages 10 and 15 and examined. 

Genotype 

At ages 10 and 15, mean heights and dominant 

heights were greater for the seed orchard stock 

than for the seed production area stock. These 

genotype effects are consistent over time and can 

be seen readily in Figure 6. The height advantage 

of the seed orchard stock over the seed production 

area is consistent over time and represents a real 

gain in height over that from the seed production 

area stock, This same trend exists for dominant 

height over time* 

Interactions 

Fertilizer x genotype 

At age 10, there is a fertilizer x genotype 

interaction on mean diameter and on mean tree 

basal area. The seed orchard stock suffers more 

of a negative response in mean diameter relative 

to the control than the seed production area stock 

for the K + N treatment, and has a larger response 

relative to the control than the seed production 

area stock for the P treatments, although the 

advantage is extremely slight for the P + K treatment, (Figure 7)- 

RESULTS AND DISCUSSION 

Site preparation x genotype 

Main Effects 

Fertilizer 

Phosphorus treatments consistently increased all 

the stand characteristics investigated, with the 

P-K-N treatments consistently showing the largest 

response. The response to phosphorus is especially visible in the diameter and height distributions. The diameter and height distributions 

from the phosphorus treatments are shifted to the 

right relative to the nonphosphorus treatments 

(contain higher proportions of larger stems). 

Examples of actual diameter distributions are 

given in Figure 1 and 2. There is a significant, 

consistent and negative effect of the potassium 

and nitrogen combined treatment on the stand 

characteristics investigated, Figures 3, 4, and 5 

show a consistent advantage over the control 

(no fertilizer) for phosphorus treatments and a 

consistent loss compared to the control for the 

K-N treatment. A possible reason for this loss is 

increased microbial competition for P in the presence of K and N to the detriment of the trees, 

Site Preparation 

There is no statistically significant site preparation effect on any of the stand characteristics investigated at age 15, However, there 

is a trend in the response of the stand characteristics to the different site preparation treatments (Figures 3 and 4), Through age 10, response 

to the v-blade and rootrake treatment was less 

than the control (Wilhite and McRee 1985, Mc&e 

and Wilhite 1986). However, at age 15, the vbladed + rootraked plots generally had higher 

basal areas and volumes per acre than the control 

plots (Figures 3 and 4). 

There is a site preparation x genotype interaction on basal arealacre and total volume per acre 

at ages 10 and a somewhat weaker interaction on 

these two stand characteristics at age 15. The 

age 10 results indicate that the seed orchard 

stock does not perform as well as the seed production area stock for the V-blade + rootrake + disk 

and the V-blade + rootrake + bed treatments. The 

seed orchard stock performs better than the seed 

production area stock for the other three treatments at age 10, At age 15, the seed orchard 

stock performs better than the seed production 

area stock for the control and V-blade treatments 

and performs worse than the seed production area 

stock for the other treatments (Figure 8). The 

trend would indicate that the seed orchard stock 

does not respond as well to the more intensive 

site preparation methods as does the seed production area stock through age 15. 

Survival 

Trends in survival with respect to site preparation show that there were significant differences 

in initial survival relative to treatment. From 

ages 10 to 15, the mortality rate has been essentially the same for all treatments except V-blade 

+ rootrake. The lower mortality rate for this 

treatment Is likely a result of less intense competition due to the slower overall growth, particularly that of height, for this treatment. 

With respect to fertilizer treatment, mortality 

rates are essentially equal (parallel survival 

curves) for all but the K + N treatment, The 

associated flatter survival curve of the K + N 

treatment is likely the result of the slower crown 

expansion accompanying the slower height growth 

rate of this treatment. 
Mortality rates of the two genotypes are essentially tbe same from age 10 to 15, paralleling 

their very similar height growth patterns. At age 

15, the seed orchard stock maintains a remnant of 

its initial seedling survival advantage. 

CONCLUSIONS 

The analyses of variance and graphs of the stand 

characteristics at ages 10 and 15 on this somewhat 

poorly drained site indicate that: 

I. Survival patterns by treatment parallel the 

height growth patterns by treatment. 

REL. FREQ. 

0.4r 

2. The fertilizer x genotype and site preparation x genotype interactions suggest 

that such interactions found under the low 

level of genetic selection in this study 

should be considered when planning genetic 

tests. 

3. Seed orchard stoek produced less basal 

arealacre with increasing site preparation 

intensity than did the seed production 

area stoek. 

4, The V-blade + rootrake site preparation 

treatment consistently reduced production 

relative to the control through age 10. 

V-blade, V-blade + rootrake + disk and 

-2345670910 

DIAMETER CLASS (IN1 

Figure 1.--Relative frequency of diameter at age 15 

for no mechanical site preparation (Block I). 

REL. FREQ. 

0.4r 

OIAMETER CLASS (IN1 

Figure 2.--Relative frequency of diameter at age 15 

for v-blade + rootrake + bed (Block I). 

Nu fertilizer 

by fertilizer 

No fertilizer 

by fertilizer 
No fertilizer 

8 * 

u 

v-blade, rootrake contra1 v-blade v, rr, disk v, rr, bed 

Site Preparation Treatmant 

Figure 3.--Basal area per acre by site preparation and 

fertilizer treatments at age 15. 

No fertilizer * 

2000 

v-blade, rootrake control v-blade v, rr, diak v, rr, bed 

Site Preparation Treatment 

Figure 4.--Total cubic foot volume per acre by site preparation 

and fertilizer treatment at age 15. 

Mean Height (f t .I 

Control 50 

40 50 lb. P. 200 lb. N ----. 

30 100 lb. K, 200 lb. N 

------ 

20 50 lb. 200 P + lb. 100 N lb. K 

.... '..'......... 

10 

0 

0 12 3 4 5 6 7 8 9 101112131415 

Age (years1 

Figure 5,--Mean height through time by fertilizer treatment. 
Mean Height (ft .) 

50 

Seed Production Area 

Orchard 

----. 

Age (years1 

Figure 6.--Mean height through time by genotype. 

Mean Dbh (in .) 

Seed Production 

Area 

4 0 

Seed Orchard 

Stock 

A 

IOOK, 

6 c 200 N control 50 P, 200 N 50 P + 100 K, 200 N 

Fertilizer Treatment 

Figure 7.--Mean diameter breast height by fertilizer treatment 

and genotype at age 15. 

BA/ac (sq. ft.) 

Seed Production 

Area 

0 0 

Seed Orchard 

Stock 

Q 

Q 

I I 1 I 

Control v-blade, rootrake v-blade v, rr, disk v. rr ,bed 

Site Preparation Treatment 

Figure 8.--Basal area per acre by site preparation treatment 

and genotype at age 15. 
V-blade + rootrake + bed consistently 

showed increased production over the 

control. 

5, The fertilizer treatments significantly 

a£ fected all stand characteristics. The 

P + M and P + K + M treatments increased 

the growth of the stand characteristics 

relative to the control. 

6. Great care should 'be exercised in generalizing results from this study to 

operational situations because of the 

chemical hardwood control imposed on all 

treatments, 

LITERATISRE: CITED 

Clutter, J, L,, Warns, W. Re; Brister, GI K,; 

Rhenep, J. M, Stand structure and yields of 

site-prepared loblolly pine plantations on the 

Lower Coastal Plain of the Carolinas, Georgia 

and North Florida, Gen. Tech. Rep, SE-27, 

Asheville, NC: U. S, Department of Qriculture, 

Forest Service, Southeastern Forest Experiment 

Station; 1984. 173 pp. 

McKee, W. H., Jr, and L. P. Wilhite, Loblolly 

pine response to bedding and fertilization 

varies by drainage class on lower Atlantic 

Coastal Plain sites. Southern Journal of 

Applied Forestry 10(1):16-21; 1986. 

Wilhite, L. P. and W, H, McKee, Jr. Site preparation and phosphorus application alter early 

growth of loblohly pine. Southern Journal of 

Applied Forestry 9(2):103-109; 1985. 
PHOSPHORUS DISTRIBUTION IN THREE LOBLOLLY PINE 

David J, Paganelli, Joseph N. Bockman, and James A. Burger 2/ 

Abstract -- In the summer of 1982, three forest sites at the 

Reynolds Homestead Research Center on the Virginia Piedmont were , clearcut. In the fall of the same year, all three sites were prepared using one of the following treatments: 1, sheartrake, 

disk (3-passes); 2. chop and burn (high-intensity burn); and 3. 

shear-disk (1-pass). During March of 1983, 1-0 genetically 

improved loblolly pine (Pinus taeda L.) seedlings were planted on all sites, After three growing seasons biomass and total P 

content of planted pines were greatest on the shear,rake,disk 

site. Total biomass and P content of native vegetation, and 

forest floor were greatest on the shear-disk area. Total P in 

the upper 15 cm of mineral soil was also greatest on the 

shear-disk area. Total system P was highest on the shear-disk area and lowest on the site that was chopped and subjected to the 

intense fire. Pine height, root collar diameter and volume were best on the more intensively prepared areas and no evidence of P 

deficiency in planted pines was found for any of the three 

plantations. Although intensive site preparation methods did 

influence the distribution of P on these sites, there was no short-term effect on P nutrition or early growth of planted 

pines. 

Plantations of southern pines have been shorn 

to respond to P fertilizer on many sites in the 

lower Coastal Plain (Arerett, 1986; Fisher and 

Garbett, 1980; Pritchett and Smith, 1972; Wells 

and Allen, 1985; Wells and Crutchfield, 1969; 

Wells et al., 1973; Wells et al., 1986). But only 

recently, has evidence been provided of widespread 

P response on Piedlmont sites. Wells and Allen 

(1985) reported that although individual responses 

varied considerably, loblolly pine showed an overall mean volume response to P fertilizer 

application in 49 Piedmnt fertilization studies. 

Since some sites on the Piedmnt are apparently 

deficient in P, it may be important to understand 

the effects of forest management activities, 

particularly site prepration, on P distribution 

if pine growth is to be maximized. 

The objective of this study was to determine 

the effects of three cornmn site preparation 

methods on site P distribution, tree size, total 

bi-s and overall nutrition of planted pines 

during the third growing season of three loblolly 

pine plantations on the Virginia Piedmnt, 

During the summer of 1982, three similar 

forested sites at the Reynolds Homestead Research 

Center in Critz, Virginia were clearcut. 

Pre-harvest stand and site characteristics are presented in Table 1. Each area was site prepared 

using one of the following methods: 1. 

shear,rake,disk (three passes); 2. chop and burn 

(high-intensity burn) ; or 3, shear-disk (one 

pass). In March of 1983, all areas were planted 

with 1-0 genetically improved loblolly phe. 

The three plantations were reentered during 

August of the third growing season and 30 to 50 

(depending on plantation area) randomly-located sample plots were established on each area. At 

each sample2plot all native vegetation within and 

above a 1 m sampling £ram was collected. In 

addition, the forest floor was sampled and a soil 

sax@le was collected below a 23 cm circle to a depth of 15 cm. Living roots were seprated from 

this soil volume and were analyzed separately to 

obtain estimates of bel~round biomass and P 

content, which were then added to aboveground 

estimates of native vegetation, The nearest 

planted pine to each sample plot was destructively 

sampled for biomass and P content evaluation. 

"paper presented at Southern Silvicultural All tissue samples were dried at 65'~ for 24 

Research Conference, Atlanta, Georgia, Novaber hours and biomass was determined. Subsamples of 

4-61 986. all soil and tissue samples were digested using a 

"Research Specialist, Laboratory Supervisor, micro-Kjeldahl procedure and were analyzed for 

and Associate Professor of Forest Soils, Forestry total P using a Technicon AutoPanalyzer 11. 

Ileptartmnt, Virginia Tech, Blacksburg, Virginia 

24061. Pine growth masurements were made in mv-er 
Table 1. Pre-harvest stand and site characterization of three 

forested research areas located at the Reynolds 

Homestead Research Center, in Patrick county, on the 

Virginia Piedmont (adapted from Fox, 1984). 

Ave. Major 'site Index Basal Total 

Treatment Slope Soil Yellow-poplar Ajea Vojume 

Area Series (m) fm /ha) (m /ha) 

Shear,rake, 17 Cecil 28 23.8 115.9 

disk 

Chop,burn 17 Cecil, 28 24.6 112.2 

Hayesville 

Shear-disk 11 Cecil 28 22.2 121.4 

--- 

I Base age 50 years. 

of the third growing season, Six to eleven 

(depending on plantation area) 0.04 ha plots wre established in each plantation and height and root 

collar diameter was determined for all ~lanted 

pines within the plots. Volume index (d h) was calculated on an individual tree basis, Estimates 

r of trees per hectare were based on the nunher of trees foud in the measurement 

plots. 

Pine foliage samples used for nutrient 

analyses were collected during Paove&r, following 

the third growing season, from all trees in the 

measurement plots described above. Samples 

consisted of needles from the uppermost fully 

elongated whorl on the south side of the tree, as recommended by Powers (19841, and Wells and Metz 

(1963). Nitrogen and P concentrations of this 

tissue were determined from a micro-Kjeldahl 

digest using a Technicon AutoAnalyzer 11. Cation 

concentrations were detemjnd from dry-ash& 

samples using atomic absorption spectropbtomt ry . 

The P content of the surface 15 cm of mineral 

soil was greatest on the plantation that received 

the lowest intensity site preparation (Table 3). 

The shear-disk area had mre total P than the 

other areas even though it also had the lowest 

bulk density (Table 3) . The shear,rake,disk and chop and burn 

plantations consistently had the rmst pines per 

hectare, had taller trees with larger root collar 

diameters and had larger volume index values than 

did the shear-disk plantation (Table 4) . Concentrations of P in pine tissue collected 

after the third growing season provided no 

evidence of existing or impending P deficiency in 

any of the three plantations (Table 5). 

Phosphorus concentrations of from 0.13 to 0.14 % 

are well above the 0.10 to 0.11 % range comnrtnly 

used as a critical P response level for loblolly 

pine. Levels of other nutrients in pine tissue are also higher than reported critical levels or comnly reported concentrations. 

DISCUSSION 

Total pine biomass (incuding roots) was greatest in the mst intensively prepared 

plantations during the third growing season (Table 

2) . The shear, rake, disk plantation pine biomass was highest, followed by that of the chop and burn 

and shear-disk areas, The P content of planted 

pines directly paralleled biomass. 

Biomass and P content of native vegetation were greatest on the shear-disk plantation 

implying less success at coqtition control with 

this treatment but greater success at nutrient 

conservation (Table 2) . 

Forest floor biomass and P content were also 

greatest for the shear-disk plantation. 

Maintenance of the forest floor during site 

preparation conserved site P and led to more rapid 

stabilization of this site (Table 2). 

The shear,rake,disk treatment relocatedl 

logging debris, the forest floor and some surface 

soil to windrows during the raking process. Since 

this mterial contained PI it is safe to say that a redistribution of site P occurred as a result of 

site preparation. Since windrows were placed in 

the drainages and then burned it is likely that some P was lost from the site by localized 

volatilization (Flinn et al., 1979; Hamod and 

Jackson, 1975; Kodama and Van Lear, 1980), or afterwards, by ash loss from surface water flow. 

The chop and burn area also experienced a redistribution and probable reduction of site P 

reserves. The fire was very intense and likely 

volatilized some P contained within the logging 

debris and forest floor. Other sources of 

probable P loss were loss of P-bearing ash from 
Table 2. Biomass and P content of planted pines, native 

vegetation and forest floor during the third 

growing season of three loblolly pine plantations on the Virginia Piedmont. 

System 

Component 

Treatment Biomass P Content 

Area (kg/ha) (kg/ha) 

- -- 

Planted Pines Shear,rake,disk 928 0.7 

Chop,burn 659 0.5 

Shear-disk 327 0.3 

Native Shear, rake,disk 5,901 5.3 

Vegetation 

Chop,burn 5,496 4.8 

Forest Floor Shear,rake,disk 10,345 5.2 

Chopiburn 14,579 2.8 

Shear-disk 39,597 19.3. 

-- 

Totals Shear,rake,disk 17,174 11.2 

Chop,burn 20,734 8.1 

Shear-disk 49,809 29.7 

the site by convection currents during the fire 

and the action of wind and water following the 

fire. In any event, the forest floor and most 

logging debris were absent from the site at the 

time of planting, irrrplying a significant 

redistribution or loss of P and other nutrients. 

$he plantation which received the shear-disk 

treatment experienced little loss of P, other than 

that directly associated with harvest. All forest 

floor, logging debris and nonlnerchmtable 

material was left on the site, resulting in rapid 

stabilization after site prepration. This 

treamnt was con~rvative with regard to the 

minternee of site nutrient reserves, but failed 

to achieve ad-ate competition control. 

??he tm plantations which experienced the most 

drastic redistribution of P and had potential for 

P loss, did in fact have lower P levels in surface 

soil, forest floor and native vegetation after 

three grming seasons (Tables 2 and 3). Despite this fact, pine growth was best on the mre intensively prepared areas and pine foliar P 

mn~~trations were rently more than ad on all three areas. This implies that P did not 

limit pine growth in these three plantations at 

age three, regardless of site prepration effects on P redistribution and loss (Tables 4 and 5). 

Table 3. Phosphorus content and bulk density 

of the surface 15 cm of mineral soil. 

during the third growing season of 

three loblolly pine plantations on the Virginia Piedmont. 

P content of 

Treatment Bulk Dengity surface soil 

Area (s/cm ) (kgha) 

Chop, burn 

Shear-disk 1.03 849,9 
Table 4. Treedhectare, height, root collar diameter and volume 

after three growing seasons for three loblolly pine 

plantations on the Virginia Piedmont. 

Treatment ~rees/ha Height Root Collar Volume31ndex 

Area (m) Diameter (em) (em 

Table 5. Pine foliar nutrient concentrations at the end of the 

third growing season of three loblolly pine plantations 

on the Virginia Piedmont. 

Treatment N P K Ca ..................... Mg 

Area ( % ) -------------------- 

I. The highest levels of P in native vegetation, 

forest floor and surface soil were found in 

the plantation that had received the lowest 

intensity site preparation. 

2. The lowest levels of P were found in the 

plantation that had received the intense burn. 

3. Total pine biomass, trees per hectare, root 

collar diameter, height and volume index were 

greatest in the plantations that had received 

the mst intensive site prepration. 

4. No apparent P deficiency was present or 

imminent in any of the three plantations after 

three growing seasons. 

The authors wish to thank Chanpion 

International Corporation for providing both 

financial and logistical support for this study. 

LI-m CITED 

Everett, C. J. 

1986. Phosphorus fertilization of loblolly 

pine: fate of applied P and effects on 

phoshatase activity sixteen years following 

fertilization. Agronamy Abstracts 78:259. 

Fisher, R. F. and W. S. Garbett. 

1980. Response of semimature slash and loblolly 

pine plantations to fertilization with 

nitrogen and phosphorus, Soil Sci, Soc. Am. 

J. 44:850-854. 

Flinn, D. W., P. Hopnans, P. W. Farrell and J. 

M . James. 

1979. Nutrient loss from the burning of Pinus 

jadiata logging residue. Aust. For. Res. 

9:17-23. 

FOX, T. R. 

1984. The impact of harvesting and site 

preparation on nutrient dynamics, soil erosion 

and stream water quality in the Virginia 

Piedmont. M.S. Thesis. Forestry Dept. 
Virginia Tech, Blacksburg, VA. 296 pp. 

, C. E, and W, D. Jackson. 

1975, A-spheric losses of four plant 

nutrients during a forest fire, Aust, For. 

38: 92-99. 

Kodama, H, E, and D. H. Van Mar. 

1980, Prescribed burning and nutrient cycling 

relationships in young loblolly pine 

plantations. S. J, Pgpl, For. 4:118--121, 

Powers, R. F. 

1984. Estimating soil nitrajen availability 

through soil and foliar analysis. pp. 353-379, In E. L, Stone (ed.) Forest Soils and 

Trea-nt Impacts. Proc, Six. N. Amer. For. 

Soils Conf,, June 19-23, 1983,, Knoxville, TN. 

Pritchett, W. L, and W. H, Smith. 

1972, Fertilizer response in young pine 

plantations, Soil Sci, Soc, Am. Proc. 

36:660-664. 

@ells, C. Go, J. R, Craig, M. B. Kane and H. L. 

Allen. 

1986. Foliar and soil tests for the prediction 

of phosphorus response in loblolly pine. Soil 

Sci, Soc. Am. J. 50:1330-1335. 

Wells, C. G. and D. N. Crutchfield. 

1969. Foliar analysis for predicting loblolly 

pine response to phos&orus fertilization on wet sites. USDA For. Serv. Res. Note SE-128. 

Wells, C. Go, D. M. Crutchfield, N. M. E3erenyi and 

C. B. Davey. 

1973, Soil and foliar guidelines for phosphorus 

fertilization of loblolly pine. USX For. 

Serv. Res. Pap. SE-110. 

Wells, C. G. and L, J. Metz. 

1963, Variation in nutrient content of loblolly 

pine needles with season, age, soil, and 

position on the crown. Soil Sei. Soc. Am. 

Proc. 27:90-93, 

-Wells, C. G. and H. L. Allen. 

1985. When and where to apply fertilizer, A 

loblolly pine management guide. USElrA For. 

Serv, Gen. Tech. Rep. SE-36. 
EFFECTS OF SITE Ai"rELIOKAT10h Olv GKOlriTR AhD YLLLU OF SLASki AID LOBLOLLY 

PIhES PLASTEU Oh A CADDO SILT LOAM ih SOUThWESTEkk LOULSIA~~// 

Abstract: 5lash (Piflus e2Ziat;t;ii i.ngelm. var. ezliottii) and 

loblolly (Pinus taeda L.) pine 5eedlil%g~ were planted on a poorly 

drained Caddo slit loam in southwestern Louisiana in a completely 

randomrzed block design. The ztudy alea was skeared and burned, 

then plots were either harrowec, bedded, or lert untreated. ~fter 

15 growing seasons, merchantable slas-i pines on the L mechanical 

treatments were significantly taller &nd had significantly greater 

average d,b.h, and inside bark (i.b,) and outslde bark (0.b.) 

volumes per tree than those on checks, bieans were also 

significantly different between the harrowed and bedded treatments 

for all tour variables except total height. however, i.b. and 0.b. 

volumes per hectare were not signikicantly ditferent among 

treatments, and there were no signiticant ditterences In slash pine 

density among treatments. dercnantable 15-year-old loblolly pines 

did not differ significantly irA mean c.b.b., height, and i.b. and 

0.b. volumes per tree or per hectare gmong the three treatments. By 

age 15, almost 60 percent of tte slas~~ pines and almosr. 50 percent 

of the loblolly pines were severely irfected with fusikorm rust, 

such that future stand potential was seriously reduced. 

IhTRODUCTION METHODS 

In this study, the growth and yield responses 

of slash (Piflus e22iottii Engelm. var. elliottii) 

and loblolly (Pinus taeda L.) pines could be 

assessed on a poorly drained silt loam site that 

is free ok pimple mounds. The 5-, lo-, and 

15-year results are reported, and these addressed 

two objectives: (1) is growth and yield of slash 

and loblolly pines better on the two mechanically 

prepared plots than on checks and (2) are there 

differences between the two mechanical treatments? 

In addition, the severity of fusiform rust 

infection for both species greatly affected the 

results. 

- " Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

- '/ Cooperative study with Owens-Illinois, Inc., 

Orange, Texas. 

- 31 Silviculturis t , USDA Forest Service, Southern 

Forest Experiment Station, 2500 Shreveport 

Highway, Pineville, Louisiana 71360. 

The study area, located in southwestern 

Louisiana, had a uniiorrn slope of 0 to 3 percent. 

The soil, a poorly drained Caddo silt loam (Typic 

Glossaqualks, kine-silty, siliceous, thermic), had 

slow surkace drainage and slow permeability with z 

perched water table at or near the surface in 

winter. In the early 1950's, longleaf pine (Pinus 

paZustris blill.) was established by direct 

seeding. The resulting stand of trees, 18 to 20 

em in d.b.h., was clearcut, and the residual woody 

vegetation was sheared in September 1969. 

Hardwood competitors were never again a 

significant percentage of stand basal area. 

The 39- by 39-m research plots were burped in 

the winter of 1969-70. Burning was done to 

facilitate the planting of check plots and the 

installation of two mechanical treatments in 

September 1970: (1) harrowed--the plots were 

harrowed twice with an offset disk to reduce grass 

competition and (2) bedded--the plots were 

harrowed and then bedded with a bedding harrow 

that was equipped with a shaping roller. Beds 

were spaced 2.4 m apart; total bed height 

after settling averaged about 36 cm from furrow to 

crest. 
In February 1971, either slash or loblolly pine 

seedlings (1-0) were planted at 256 planting spots 

per research plot, Planting locations were 

spaced about 2.4 by 2.4 m apart, To ensure 

adequate density, two seedlings were set by hand 

about 15 cm apart at each location. If both 

seedlings survived until October 1972, the least 

vigorous seedling was rogued. Measurement plots 

consisted of the central 100 planting locations on 

each research plot. 

The study was initiated as a completely 

randomized block design with four blocks. The 

main treatment effects were pine species and site 

amelioration. However, data for each pine species 

were analyzed separately because their development 

on this site was radically different, and thus a 

formal sratistical comparison was not worthwhile. 

The three treatments were contrasted by the 

following orthogonal trend comparisons: (1) check 

vs. the average for the two mechanical treatments 

and (2) harrowed vs. bedded (p=0.05). 

On the 5-year-old slash and loblolly pine 

plots, mean height and pine density were reported* 

For the 10- and 15-year-old pines, mean d.b.h., 

height, inside bark (i.b.) and outside bark (0-b.) 

volume per tree, pine density, 0.b. and i.b. 

volume per hectare, and basal area per hectare 

were measured and compared to determine if there 

were any treatment differences. 

At age 5, total height to the nearest 3 cm was 

measured with a calibrated pole. At age 10, total 

height to the nearest 3 cm was measured with a 

calibrated pole, and d.b.h. was measured to the 

nearest 0.3 cm with calipers. Pines were classed 

as suppressed, intermediate, codominant, or 

dominant. The same features were measured at age 

15, except heights were measured to the nearest 30 

cm with an altimeter and d.b.h, was measured with 

a diameter tape. 

Inside bark and o.b. individual tree volumes 

were calculated for slash pine with Lohreyfs 

(1985) volume equations. Loblolly pine individual 

tree.volumes were calculated with Hasness and 

Lenhart" (1972) volume equations. Pines less 

than 1.4 m tall were not included in the 10- and 

15-year measurements because these trees could not 

be used in d.b.h. and volume estimates. 

No fusiform rust (caused by Cronar%ium 

quercuum (Berk.) Miyabe and Shirai f, sp. 

fusiforme Burdsall and Snow) information was 

recorded at age 5, but fusiform rust galls were 

noted on some of the main stems at age 6; these 

data were used as rust data for the 5-year-old 

pines. At ages 10 and 15, presence of fusiform 

rust was noted if the pine had stem infections or 

the pine had become multistemmed (witches' 

brooms ) . 

The percentage of 10- and 15-year-old slash 

and loblolly pines with fusiform rust infection 

are reported in two groups: (1) percentage of 

living pines with witches' brooms and (2) 

percentage of stem-infected pines among those 

without witches' brooms. However, the overall 

data are only for dominant and codominant pines 

classed as free of stem rust and for pines without 

witches' brooms, because any measurements of 

d.b.h, or volume estimates of trees with witches' 

brooms would be very inaccurate. 

RESULTS AhD DISCUSSiUh 

Fusiform kust 

Fusiform rust infection was a serious problem 

for both species. By age 10, almost half the 

slash pine and one-third the loblolly pine were 

classed as having witches' brboms (table 1). 

There were no significant treatment ditferences 

for slash pine, but a significantly greater 

percentage of loblolly pines were seen with 

witches' brooms on harrowed and bedded plots than 

on checks. At age 15, the number of living trees 

with witchesf brooms declined considerably for 

both species. Slash pine exhibited a greater 

percentage of witches' brooms on checks than on 

harrowed or bedded plots. However, there were no 

significant treatment differences &or loblolly 

pine at age 15. 

Fusiform rust infection generally increases 

over time and is often associated with the 

premature death of pines (Nance and others 1981). 

The rapid decline in the number of living trees 

with witches' brooms reflects this relationship, 

and, especially for slash pine, total stand 

mortality between ages 10 and 15 was largely 

associated with fusiform rust. 

For slash pines without witches' brooms, the 

incidence of stem-rust was not significantly 

different among the three treatments at ages 5 and 

10 (table 1). Rust infection averaged almost 

half for 5-year-old and about 40 percent for 

10-year-old slash pines. For loblolly pines, rust 

infection averaged over 40 percent at age 5 and 34 

percent at age 10. 

However for 15-year-old slash pines without 

witches' brooms, there was a significantly greater 

incidence of stem-rust on bedded plots than on 

checks with intermediate results on the harrowed 

plots (table 1). The incidence of stem-rust among 

15-year-old loblolly pines without witches' brooms 

was similar among the three treatments and 

averaged about 40 percent. 

Slash Pine Growth and Yield 

Five-year-old slash pines were taller on the 

two mechanical treatments than on checks, but 

there was no difference in total height between 

the harrowed and bedded treatments (table 2). 

The same pattern of height response was noted for 

pines without witches' brooms at ages 10 and 15, 

and mean d,b.h. and 0.b. and i.b. volumes per 

slash pine were significantly different among all 

three treatments. For slash pines without 

witches' brooms, volumes, basal area, and density 

per hectare values did not follow these patterns. 

There were fewer slash pines per hectare at 

age 5 on the bedded plots than on the other two 

treatments (table 2). By age 10, there was a 

greater density of slash pines over 1.4 m tall on 
'laale 1.--ine percentage or IU- ard 15-ycar-old slash and loblolly plnes 

with kusxf-orr;, rust lrfection in tr-o grsu is: percenttibe ol: llvlng trees 

with wltcries ' brooms and percentak e OX s Ler~-xi.irecttrb trees anoni; 

those cithout vitcbes' brooms 

blasn p;ne Loalolly prne 

10-year-data : 15-year-cata : lb-year-data : 15-year-data 

Percentage of Livinb sines uitb wrtcbes'brooms 

Check 46. ba* 17,St 

Farrow 48.2a 7.9, 

Bed SO. 3a 7.7a 

Means 49.1 11.1 

Percentage or sten-intected pines among those without witches' hrooms 

Check 3b .ba 

t,arrow 35.2a 

Bed 50.5a 

Fieans 41.4 

* For each age, specres, ma grovk, coiuiin means tollo\~ed by the same 

letter were not consxdered to bt srhnl~icantly difrerent based on 

interpretation or the tho orthogonal t-end comparisons: (1) check vs. 

average tor the two niechanical treatme~*ts ana (2) t~arrowed vs. bedded 

(p=0.05). 

Table 2.--!.ieasurements ok slash pine at tkirre diiterent ages on a Caddo silt 

loan1 flatwoods in southwestern Louisiana* 

- : 0. -1. volunie : I. b. volume : Pines 

Treatment : 0.b.h. : tieight : iter tree : per tree : per ha 

5 years 

Check -..-*A i .6a+ -- 

harrow -- 2.lb -- 

Bed -- 2.4b -- 

10 years 

Check b. 43 5. &a 23.5a 12.3a 622ab 

harrow 1U .Ub 6.6b 32.2b 17.30 702b 

bed 11.2~ 7.lb 43.4~ 23. bc 572a 

I5 gears 

Check L4.La 4.4a YLba 55.5a 70%a++ 

harrow 14.bb ICI*Lb 1Ubebb 55.35 845a 

Bed 16.iic l(i.bt 124 .lit bu.lc b94a 

hone of the measured trees showec evide~~ce of witches' brooms. 

** U.b.h, data were not collected, so volur~es could not be calculated. 

+ For each age, column means folloked by che same Letter were not considered 

to be significantly different based on xnterpretation of the two orthogonal 

trend comparisons: (1) check vs. average for the two mechanical treatments 

and (2) harrowed vs. bedded (p=C135j. 

++ lncrease in stand density dut to ingrowth by slash pine less than 1.4 m 

tall at age 10. 

/! MSE = mean square error for 15-year data. 
harrowed than on bedded plots with intermediate 

results for checks. At age 15, however, no 

significant differences in stand density were 

found among the check, harrowed, and bedded 

treatments- Also, basal area and volume per 

hectare results were not significantly different 

among 10- or 15-year-old slash pines. At age 15, 

slash ine averaged 13.9 m2 of basal area, and 3 50.2 m i.b. and 82.2 m3 0.b. per hectare across 

all treatments. 

Dominant and codominant pines free of 

stem-rust will be most of the future crop trees. 

At ages 10 and 15, dominant and codominant 

rust-free pines on the two mechanical treatments 

were taller on the average than pines on checks, 

but there was no significant difference 

between mechanical treatments (table 3). Pines on 

bedded plots had a greater mean d.b.h. and more 

volume per tree than those on checks with 

intermediate results on the harrowed plots. 

There were more 10-year-old rust-free dominant 

and codominant slash pines per hectare on the 

harrowed treatment than on the bedded treatment 

with intermediate results on the check (table 3). 

However, by age 15, there were no significant 

differences in density among the check, harrowed, 

and bedded treatments. 

At age 10, the best slash pines produced more 

i.b. volume per hectare on the harrowed plots than 

checks, with intermediate results on the bedded 

plots. But by age 15, these differences 

disappeared, when the average was 26.5 m3 i.b. 

per hectare across all treatments, No significant 

treatment differences were found at either age for 

basal area or 0.b. volume per hectare. The best 

15-year-old slash pines averaged 7.0 m2 of basal 

area and 42.8 m3 0.b. per hectare across all 

treatments. 

Loblolly Pine Growth and Yield 

For loblolly pines without witches' brooms, 

there were no significant differences in mean 

d.b.h., height, or volume per tree among the three 

treatments. The 15-year-old loblolly pines 

'averaged 9.5 cm d.b.h., 6.1 m tall, 22.2 dm3 i.b., 

and 32.6 dm3 0.b. per tree across all treatments. 

There were fewer 5-year-old loblolly pines per 

hectare on the bedded treatment than on the other 

two, but no significant differences in density 

were found for pines greater than 1.4 m tall at 

ages 10 and 15. The 15-year-old trees without 

witches' brooms averaged 820 per hectare on check, 

824 per hectare on harrowed, and 647 per hectare 

on bedded plots. Furthermore, there were no 

significant differences in volume and basal area 

per hectare for either 10- or 15-year-old 

loblolly pines. Across all treatments, 

15-year-old loblolly pines averaged 6.6 m2 of 

basal area, 16.6 m3 i.b., and 24.4 m3 0.b. per 

hectare. 

Among rust-free dominant and codominant 10- 

and 15-year-old loblolly pines there were no 

significant treatment differences. The 

15-year-old loblolly pines averaged 12.6 CNI 

d.b.h., 7.4 m tall, 36.9 dm3 i.b., and 50.1 

dm3 0.b. per tree and 245 pines, 3.3 m2 of basal 

area, 8.9 m3 i.b., and 12.1 n3 o.b. per hectare 

across a11 treatments. 

Bedding concentrates soil organic matter into 

planting ridges, which increases nutrient 

availability in the rooting zone of planted pines 

and raises the seedling's root system above 

standing water during rainy periods (Pritchett and 

Gooding 1975). On medium- to fine-textured soils, 

bedding improves aeratioa and increases the rate of 

water movement through the soil (Shoulders and 

Terry 1978). McKee and Shoulders (1970, 1974) 

determined that the growth benefits associated witn 

bedding are correlated with the amount of added 

depth to free water provided by the beds if the 

average water table depth is less than 45 cm after 

winter rains. Thus, the bedding of poorly drained 

soils can result in better slash pine growth (Mann 

and McGilvray 1974). However, planting on beds is 

often not needed on somewhat poorly to moderately 

well-drained soils (Haywood 1980, 1983, Mann and 

McGilvray 1974, Tiarks 1983). 

Based on per tree averages from the poorly 

drained site used in the present study, slash pines 

responded t o s i t e amelioration and grew best on the 

bedded plots. Among rust-free dominant and 

codominant slash pines, per tree averages were 

better on bedded plots than on checks, but there 

was no advantage to planting after harrowing, 

except for an increase in mean total height. 

However, there were no significant differences per 

hectare at age 15 for any of the variables tested, 

which suggests that site amelioration was 

ineffective. Still, one might decide to give more 

weight to the per tree results since these were 

small plots, fusiform rust greatly reduced stand 

density, and the per hectare values varied widely 

within treatments. For example, the respective 

mean square errors for 15-year-old slash pine were: 

basal area, 14.9 (m2/haj2; i.b. vojume, 255 (m3 

i.b./ha)2; and 0.b. volume, 640 (m ~.b./ha)~. 

On poorly drained soils, stands of loblolly 

pine often develop more slowly than those of slash 

pine (Shoulders 1976). However, young loblolly 

stands will often equal or surpass the growth and 

yield of slash pine stands on intermediate to dry 

sites (Haywood 1980, Haywood 1983, Shoulders 1976). 

Loblolly pine seedlings were very severely 

damaged by tipmoth (Rhyacionia spp.), but damage 

was negligible among slash pine seedlings. This 

was believed to be the reason for the slow initial 

growth by loblolly pine. Since loblolly had been 

planted on other silt loam flatwoods without 

prolonged infestations by tipmoth, poor site 

quality might have predisposed this stand to 

at tack. 

Regardless, loblolly was about rive growing 

seasons behind slash pine in diameter growth, 

height growth, and in volume production. Loblolly 

pine also did not respond to site amelioration. 

Clearly, loblolly pine was ill-suited for this 

poorly drained Caddo silt 1oar.i site. Li~~titations 
Table 3.--rieasurerients of domxnarrt and co ominant slash pine free of stem-rust 

on a Caddo silt loam tlatwoods in souttiwestern Louisiana 

: 0.b. voiurrie : 1.D. volume : Pines 

Ireatment : b.b.h. : tieight : pArtree : pertree : perha 

10 years 

Chec~ 

Harrow 

bed 

15 years 

Check 

harrow 

Bed 

* For each age, column means rollowed bv the same letter were not considered 

to be signikicantly different kased or interpretation ort the two orthogonal 

trend comparisons: (1) check vs. aver~ge for the two mechanical treatments 

and (2) harrowed vs. bedded (p=13.05). 

** Increase in number ot pines classed as codornxnant or dominant due partly to 

ingrowth by trees that were less than 1.4 n~ tall at age 10. 

+ PlSh = E'ean square error tor 15-year d, ta. 

on phosphorus uptake and root development on wet 

soils might also partially explain these results 

(burton 1471, Shoulders 1976, Tiarks and Shoulders 

1982). 

t~aywood, Janies U. Planted pines do not respond to 

bedding on an Hcadia-beauregard-Kolin silt loan 

site. Kes. hote 50-259. hew Orleans, LA: U.S. 

bepartment or Agriculture, Forest Service, 

Southern Forest hxperiment Station; 1980. 4 p. 

Fusiform rust greatly reduced the density ot 

crop trees on this site. Still, the density or 

rust-free dominant and codominant slash pine was 

sufficient on the check and harrowed plots to 

continue the rotation (Powers, and others 1981). 

However, crop tree density on the bedded plots was 

marginal. Had the bedded plots been a commercial 

stand of slash pine, the best management option 

would have been to clearcut at age 15 and replant. 

Phosphorus fertilization would be an advisable 

option for the next rotation (Tiarks 1983). 

liaywood, Janies b. Kesponse of planted pines to 

site preparation on a beauregard-Caddo soil. 

In: second biennial southern silvicultural 

research conference: Proceedings of the 

symposium: 1482 hovember 4-5; Atlanta, GA. 

Gen. Tech. Kep. SE-24. Ashville, I&: U.S. 

Department ot Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1983: 

14-17. 

Lohrey, Richard L. Step volume, volume ratio, and 

taper equations for slash pine in the West Gulf 

kegion, In: Third biennial southern 

silvicultural research conference: Proceedings 

or the synposiun: 1984 hovember 7-8; Atlanta, 

&A. den. 'iecii. kep. SO-54. iuew Orleans, LA: 

i, .S. bepartfrent of a,r~culture, Forest Service, 

bouthern Forest Lxperzrient station; 1485: 

431-4124. 

For all treatments, the density of rust-free 

dominant and codominant loblolly pine was marginal 

(Powers, and others 1981). had the loblolly pine 

treatments been commercial stands, the best 

management option would have been to clearcut at 

age 15, fertilize, and replant with slash pine. 

burton, James 0. Prolonged flooding inhibits 

growth of loblolly pine seedlings. kes. >dote 

SO-124. hew Orleans, LA: U.S. Department of 

Agriculture, Forest Service, bouthern Forest 

Experiment Station; 1971. 4 p. 

Yiann, h. E., Jr.; bicdilvray, J, f:. kesponse of 

slash pine to bedding and phospfiorus 

application in southeastern klatwoods. kes. 

Pap. SO-99. hew Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Lxperiment Station; 1974. 9 p. 

Hasness, J. kobert; Lenhart, J. David. Cubic-foot 

volumes for loblolly pine trees in old-field 

plantations in the Interior bdest Gulf Coastal 

Plain. Texas Forestry Yap. ho. 12 - January 

1072. P1acogdoci-es, TX: Schcel ot Fcrestry, 

Stephen F. Austin State University, 1472. 7 p. 

PicKee, kd. h., Jr.; Shoulders, Lugene, Depth to 

water table and redox potential of soil affect 

slash pine growth. Forest bcience. 16(4): 

399-4Ul; 1970. 
NcKee, W, H,, Jr,; Shoulders, Eugene. Slash pine 

biomass response to site preparation and soil 

properties. Soil Science Society of America 

Proceedings, 38(1): 144-148; 1974. 

Nance, Warren L.; Froelich, Ronald C.; Shoulders, 

Eugene. Effects of fusiform rust on survival 

and structure of Mississippi and Lousisana 

slash pine plantations. Res. Pap. SO-172. New 

Orleans, LA: U.S* Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1981. 11 p. 

Powers, H, R,, Jr*; Schmidt, R. A*; Snow, G. A. 

Current status and management of fusiform rust 

on southern pines. Annual Review of 

Phytopathology. 19: 353-371; 1981. 

Pritchett, W. L.; Gooding, J. W. Fertilizer 

recommendations for pines in the southeastern 

coastal plain of the United States. 

Agricultural Experiment Stations, Institute of 

Food and Agricultural Sciences Bull. 774. 

Gainesville, FL: University of Florida, 1975, 

23 p. 

Shoulders, Eugene. Site characteristics influence 

relative performance of loblolly and slash 

pine. Res. Pap. SO-115. New Orleans, LA: U,S, 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1976. 15 

P 

Shoulders, Eugene; Terry, T. A. Dealing with site 

disturbances from harvesting and site 

preparation in the lower coastal plain. In: 

Proceedings: a symposium on principles of 

maintaining productivity on prepared sites; 

1978 March 21-22; Mississippi State Univ., 

Starkville, MS. New Orleans, LA: U,S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1978: 

85-97. 

Tiarks, Allan E. Effect of site preparation and 

fertilization on slash pine growing on a good 

site. In: Second biennial southern 

silvicultural research conference: Proceedings 

of the symposium: 1982 November 4-5; Atlanta, 

GA. Gen. Tech. Rep. SE-24. Ashville, NC: U.S. 

Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1983: 

34-39. 

Tiarks, Allan E.; Shoulders, Eugene. Effects of 

shallow water tables on height growth and 

phosphorus uptake by loblolly and slash pines. 

Res. Note SO-285. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1982. 5 p. 
REMTIVE PERFOBMNCE OF IaOKLEAF COffPARED TO IAT)RIsI)LLY AND SLASH 

P IHES fiiNDER DIFFERENT LEVELS OF IFJTENSIVF: GULTIIRE~I 

Abs tract. --Longleaf, slash, and loblolly pines (Pinus 

palustris frill. , P. elliottii Enpeln. , and P. taeda I,. were 

grown under four levels of intensive culture. After 9 years, 

the treatnents greatly increased growth of all three species 

with loblolly pines benefiting the nost. Longleaf pines also 

benefited from intensive culture, but lagged far behind slash 

and loblolly in prowth on all treatnents after 9 years, 

After 25 years, 24 years after fertilizers were applied, the 

effects of intensive culture were still quite dramatic on all 

three species. The nost important change was in relative 

perfornance of longleaf pines compared to slash and loblolly. 

Height of longleaf was equal to slash and greater than 

loblolly on control plots. Height of all three species was 

equal at the lowest levels of fertilizer. At the highest 

levels of fertilizers , loblolly was clearly superior in 

growth to longleaf and slash, 

In the Southeastern United States, longleaf 

pine (Pinus palr~stris frill.) forests nay have 

occupied as nuch as 60 nillion acres before 

settlement (Tlahlenburg 1964). Intensive 

exploitation since pioneer days and a lack of 

regeneration efforts have shrunk the once vast 

lo-nleef pine forests to less than 4 millio~ 

acres todey, Huch of the remaining forests are 

natural second growtF that, nostly by chance, 

sprang up following logging of the old-growth 

tinber. Lonpleaf pine renains a comnercially 

important ttnb~r tree throughout nuch of its 

natural range, with close to 60 percent of the 

standing volume fot~nd in Alabana, Florida, and 

Georgia (Sternitzke and Nelson 1370). 

The najority of forest nanapcrs do not 

seriously cor?nider longleaf pine in their rtdnagenent planr: hecause of the slot7 early prowth 

rates conpar&*cl to slash (P, elltottii Engeln.) 

and InhlntJy !P, taeda L,) pines. Fotrever, ncnv 

foresters 1.t' t eve that the lonp-tern growtF, rat(% 

- llfaper pre-anted at Southern Silvicultur~l 

Researcl-, Conference, Atlanta, Genr~ia, FJovenber 

4-6, 19?h, 

21~rincipal Plant Geneticist, ITSDA Forec t 

service, Southern Forest Ex~erinent Station, 

Gulfport, flS 39505 

of lonpleaf is superior. Because of the high 

nuality of lonpleaf pine, it is used for many 

forest products, and many landowners are takinp 

advantape of recent inprovenents in longleaf 

regeneration techniques (Farrar and White 1983; 

Denningt on and Far rar 1983) and growing long leaf 

pine today. In the present study, relative growth 

rates of longleaf, slash, and loblolly pines are 

conpared in a 25-year-old intensive culture 

experinent. 

FMTERIALS AND f lETHODS 

The study area, about 25 niles north of 

Culfport, Hississippi, had been stocked with 

.cconi-growth lnngleaf pines before beiny clearcut 

3 n 19'c'-59. The soils are well-drained upland, 

Fine randy loans in the Poarch series and the 

Sauci c t-Susciuehanna complex. Slope varies fron 0 

to 8 -arcent on the gently rolling land. 

r-e-year-old seedlings of longleaf, slash, and 

lnblo3iy pines were bar-planted at 10- by 10-foot 

s~acinys in February and Ffarch of 1960, The design 

was a snlit plot, randomized complete block with 

four replications. Each block consisted of 15 

plots, 5 plots each of the 3 pine species, Each 

plot consisted of 100 trees (10 rows by 10 trees) 

stlrrotmded by 2 rows of border trees. The total 

siz~ of the plots, includi~~y horcler rows, was 0.52 

acres, ,: 8if ferent cultural treatment: was apvl ied 
to each of the five plots of each species. The 

treatnents are listed in table 1, 

Table 1.--Treatments and abbreviations 

Abbreviation Treatment 

C Control, no cultivation or fertilizer; 

F-0 Cultivated, but not fertilized; 

F- 1 Cultivated, with a single application 

of 100 Pbs N, 21 lbs P, and 42 lbs K 

per acre; 

F-2 Cultivated, with a single application 

of 200 lbs N, 42 lbs P, and 84 lbs K 

per acre; 

F-4 Cultivated, with a single application 

of 400 lbs N, 85 lbs P, and 167 lbs K 

per acre. 

Stunps, soil, and conpeting vegetation were 

not disturbed on control plots. Cultivated plots 

were cleared of all stumps and slash, then plowed, 

disked, and planted. Cultivation consisted of 

diskinp three tines each season for 3 years after 

planting and mowing in years 4 and 5. Fertilizer 

was applied with an agricultural spreader and 

disked into the soil in Flay 1961, 1 year after 

planting. 

Heights of all trees were measured at ages 

1, 2, 3, 4, 5, 6, 9, and 25. In addition, 

heights were measured at age 12 for the slash and 

at age 17 for the loblolly, D.b.h. was neasured 

on all trees at ages 6, 9, and 25. 

Linear regressions were fitted to l/age-log 

height transformations for a11 species/treatnent 

combinations using dominant-codoninant heights 

(the tallest 100 trees per acre) and available 

data for apes 4 through 25. These regression 

were then used to cons true t sf t e-index curves. 

Species means were compared by analyses of 

variance, Differences within treatnedt s are of 

interest, but di'fferences in most measured 

characters are significant because of the large 

response to intensive culture. For most measured 

characters, the interaction between species and 

cultural treatnent was significant; therefore each 

treatnent was analyzed separately for species 

effects. Statistical significance was tested at 

0.05 level of probability. 

RESilLTS AND DISCtlSSIOFJ 

The relative growth rates and the shape of 

the heightlage curves of the three species varied 

considerably according to cultural treatment 

(fig. 1). At ape 9, the growth of loblolly was 

clearly superior to slash, which was in turn 

superior to lonpleaf. After age 9, the growth of 

loblolly was considerably slower than slash and 

longleaf on C and F-0 plots. Average height of 

loblolly on C plots was only 41.1 feet at 25 years 

compared to 47.7 feet for slash and 51.9 for 

longleaf (table 2). The changes fn rank anong 

species on the F-O plots was similar to that which 

occurred on the C plots (fig. 1). 

As the intensity of culture increased, the 

relative growth rate of loblolly accelerated (fig, 

1); at age 25 the loblolly averaged 7 feet taller 

than the slash or longleaf on plots that had 

received the highest rates of fertilization (table 

2) * 

The longleaf pine, although starting out 

slower than the other species, equaled the growth 

of slash pine and exceeded the growth of loblolly 

at lower levels of intensive culture by the 25th 

year. 

Survival of longleaf was low on C plots due 

to severe competition. Fewer than 30 percent of 

the longleaf survived at 25 years on control plots 

cornpared to 50 percent of the loblolly and 70 

percent of the slash (fig. 2). Survival of 

lonpleaf on F-0 plots was as good or better than 

survival of slash and loblolly: Longleaf and 

slash averaged 60 percent survival compared to 44 

percent for loblolly, Survival of the longleaf on 

the fertilized plots averaged slightly higher than 

slash or loblolly (fig. 2). The necesssity of 

early competition control for survival of longleaf 

seedlings was clearly evident in this study. 

The nethod of competition control, i.e., 

cultivation two or three tines a year for the 

first 3 years does not appear to be desirable, 

however, The average height of longleaf was lower 

on F-0 plots than on C plots, 46.5 feet versus 

51.9 feet respectively (table 1). A study of soil 

chemistry in this planting at age 23 (fig. 3) 

showed that cultivation alone reduced organic 

natter and dcro-nutrients (such as copper), and 

the soil on longleaf plots was affected much more 

than soil on loblolly plots. After 23 years, or 

20 years after cultivation ceased, organic natter 

content was only 1.1 percent on F-0 plots compared 

to an average of 1.6 percent on the other plots. 

The nutrients mobilized by oxidation of the 

organic matter during cultivation could not he 

captured and recycled by the slow growing 

longleaf, resultinp in loss of nutrients in the 

soil and poorer growth. The use of herbicides in 

this study would likely have resulted in 

significantly less long-tern environmental danage, 

Basal area of longleaf is conparable to slash 

and loblolly on all plots except the controls 

(fig. 21, Longleaf averaged greater in d.b.h- than 

slash or loblolly on C plots (table I), but 

survival was so mc? lower that the longleaf 

averaged only 32 f t- basal area per acre conpared 

to 42 ft2/acre for loblolly and 55 f t2/acre for 

slash pine, bsal area on F-1 and F-2 treatnents 

was equal for the three species, Longleaf basal 

area on F-0 and F-4 plots was intemediate to 

slash and loblolly. 
Table 2.--Average hefght and d.b,h. at 25 years for longleaf, slash, 

and loblolly pines under different levels of intensive culture 

- 

~rea tnen</ 

Species C F-0 F-1 F-2 F-4 

Weight (feet) 

Longleaf 51.9*?/ 46.5" 58.1 60.1 59,4* 

Loblolly 41.1" 42.7" 58,6 61,O 67.3" 

Slash 47.7" 51.5" 59.0 62.0 60,0* 

d.h,h. (inches) 

Slash 6.40" 6.91 8.36 8.82 9 .00* 

1/~ee table 1 for treatment. - 

2/~ignificant differences within colunns at 0,05 are indicated - 

by an asterisk, 
CONTROL 

No Slte Prep. 

t = 

Slash .++*' / 

I LOW FERTILIZER 

1 100-21-42 Ibslacre. NPK 

Cultivated 

Lobloll y 

t 

t 

t 

5 10 16 20 25 

AGE 

CULTIVATED 

lntenslve Site Prep. 

ME* 

HIOH FERTILIZER $*fitCf 

400-85-167 Ibslacre NPKt.** 

t I 

Loblolly &.*' 

t 

t I * * +ti I 

5 10 16 

AGE 

Figure 1.--Weight versus age curves for three southern pine species under different cultural treatments. 

Curves are derived from linear regressions of log height-l/age transformations. Hedim fertilizer 

(F-2) is not shown for simplicity. 
C) 

0 

v8 

V) 

F-I 

BASAL AREA 

m 

TREATMENT 

Flp~re 2.--25 vear snrvival and hasal area for three southern pine species under five different 

eitltural. treatnents, See table 1 for explanation of treatnents. 
CONCLIIS IONS LITERATURE CITED 

The range of treatnents in this experiment 

actually sinulated a range of site auality from 

poor to average. The growth of longleaf was as 

good as slash and loblolly under nost conditions. 

Longleaf would appear to be nore a desirable 

species to plant because it is naturally 

resistant to fusifom rust and southern pine 

beetles. Longleaf also generally yields highervalued fores t prodtic t s. Recent advances in 

planting techniques, competition control, and 

brawn-spot suppression by chemical or genetic 

manipulation will hopefully lead to a revival of 

interest in regeneration and managing longleaf 

pines. 

ORGANIC 

MATTER 

CULTURAL TREATMENTS 

Dennington, R. R,; Farrar, R. If., Jr. Longleaf 

pine managenent. Atlanta, GA: U.S. Department 

of Agriculture, Forest Service, Region 8; 

1983; R8-FR3-1983, 17 p. 

Farrar, R. H., Jr.; White, J. B. Early 

development of longleaf pine planted on 

prepared sites in the East Gulf, In: Jones, 

Earle P., Jr., ed. Proceedings, 2d biennial 

southern silvicultural research conference; 

1982 November 4-5; Atlanta, GA. Gen. Tech. 

Rep. SE-24. Asheville, NC: U. S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1983: 109-117. 

Schidtling, R. C. Species and cultural effects 

on soil chemistry in a southern pine plantation 

after 24 years. In: Shoulders, Eugene, ed. 

Proceedings, 3d biennial southern silvicultural 

research conference; 1984 November 7-8; Atlanta, 

GA. Gen. Tech. Rep. SO-54. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1985: 

573-577 . Sternitzke, H. S.; Nelson, T. C. The southern 

pines of the United States. Econonic Botany. 

24: 142-250; 1970. 

Flahlenburg, \I. G. Longleaf pine: its use, ecology, 

regeneration, protection, growth, and management. 

Flashington, DC: Charles Lathrop Pack Forestry 

Foundation and U.S. Departnent of Agriculture. 

Forest Service; 1964. 429 p. 

Figure 3 .--Effects of cultivation and 

fertilization on organic matter and copper 

content of soils 24 years after treatment 

(Schidtling 1985). See table I for 

explanation of treatnents. 
CWACTION ALTERS SOIL PHYSTCAL PROPERTIES -AND ROOT GfZOWTH OF 

G. L. Simons and P. Eo pope2/ 

Abstract .--Sot 1 s at two field sites were subjected to i ncreasing compaction and changes 

in soil physical properties and root responses of inoculated and noninoculated 

ye1 1 ow- L.1 and sweetgum 

seedl in were inoculated in 

(contro ntaining the mycorr 

or G. treatments and a 

established at each site and 1-0 seedlings were grown for one year. Surface bulk 

densities increased and total and ai r-filled porosities decreased with increasing 

compaction at each site. Mycorrhizal treatments did not significantly affect root growth 

at ei ther site. After one year, roots of seed1 i ngs from a1 1 treatments were mycorrhizal . At both sites, root length and weight of sweetgum were greater than yellow-poplar on all 

compaction treatments. Root responses were greater at Site 1 due to lower bulk densities 

and a higher soil moisture content. With the exception of sweetgum at Site 1 root 

growth decreased significantly as surface bulk density increased above 1.30 Mg mL3. 

INTRODUCTION 

A reduction in potential productivity of forest 

soils resulting from compaction is of major 

concern to foresters and land managers, A 

reduction in the growth rate of trees in 

compacted soils has been reported for Virginia 

pine (Kreh et al. 19841, loblolly pine (Lockaby 

and Vidrine 1984; Mitchell et al: 1982; Simons 

and Ezell 1982; Hatchell et a1. 19701, ponderosa 

pine (Froelich 19791, radiata pine (Sands et al. 

19791 and Douglas-fir (Wert and Thomas 1981). 

The reduced growth rates are usually attributed 

to changes in soil physical properties, primarily 

increased bulk density and strength and reduced 

soil aeration. 

The su rvi val of transplanted seed1 i ngs depends 

largely on root penetration and exploration of 

the soil profile. Because of the complexity of 

root studies, relationships between root growth 

and soil compaction have not been studied 

extensively. The extent to which growth Is 

reduced and the soil conditions which limit root 

growth have not been well-defined. Two 

objectives of this study were to characterize 

changes in soil physfcal properties associated 

with increases in compaction and to determine if 

root growth of 1-0 yellow-poplar and sweetsum 

seedlings is affected by changes in these soil 

properties. 

U~aper presented at Southern Si 1 vicul tural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986, 

"~raduate Research Assistant and Associate 

Professor, respect i ve1 ye Department of Forestry 

and Natura 1 Resources, Purdue University , Wesi 

Lafayette, IN 47907. 

High quality nursery stock may be a means of 

increasing site productivity . Recent work has 

demonstrated that the quality of some species of 

hardwood seedlings produced in the nursery is 

improved by endomycorrhi zal colonization of the 

root systems (Bryan and Kormanik 1977; Kormani k 

et a1. 1982; South 1977; Schul tz et a1 . 1981 1, 

Species of hardwoods whf ch show a significant 

growth response when inoculated wi th 

endomycorrhi za1 fungi following soi 1 

steri 1 ization or fumigation include sweetgun 

(Gray and Gerdemann 1967; Korman ik et a1 . 1977 1, 

ye1 1 ow-pop1 ar (Clark 1963; Gray and Gerdemann 

19671, sycamore (Pope 19801, and white ash (Pope 

and Holt 1981). Currently, there are no studies 

which examine the field performance of inoculated 

seed1 ings grown in compacted soils. The thi rd 

objective of this study was to deterilrine tho 

influence of the endomycorrhizal fungi Cikmus 

or G. on the root growth 

of ye1 1 ow-pop1 ar and sweetgum seed1 i ngs 

inoculated f n the nursery and grown in compacted 

soils* 

WTERIALS AND METHODS 

Yellow-poplar and sweetgum were selected 

primarily because of morphological differences in 

the root characteristics of the two species. 

Typically, sweetgum has a very fine and highly 

branched (fibrous) root system; yellow-poplar 

roots are comparatively coarse and less branched. 

species (Go and G. 

1 were chosen sults of an 

earlier study indicated that both yellow-poplar 

and sweetgum demonstrated a high mycorrhizal 

dependency for these two fungal species (Pope et 

a1. 1983). 
area in each repficatlon served as an undjsturbed 

control (CON f , 

Yellow-poplar and sweetgum seed were sown at 

Vallonia State Edursery, Vallonia, IN 9n May, 

1984. Seedbeds were f noculated one month later 

with mi tu re i nocu 1 urn of fi. 

or fi. m or sterilized pot 

soil. Inoculurn cons~st.fng of soil , spores, and 

chopped roots of petun i a, was incorporated into 

the sedbsd betwesn the raws of newly geminated 

seed1 ings to a depth of 5 crn f described by Menge 

and Timer 19821 at a con~qntration of 

approximately 21,500 spores2m . Seedbeds wer 

thinned to 108 seedl l ngs m ( 10 seed1 i ngs ft-'] 

in July, 1984. Seed1 l ngs were watered and 

fertil ized under standard nursery practices, In 

November? 1984, seedlings were undercut at: a 

depth of 20 cm, mechgnically lifted, and placed 

in cold storage at 4 C, Lateral roots (< 5 mm 

diam) of ten seedlings from each rnycorrhizal 

treatment were cleared with KOH and sSiained with 

trypan blue (Phil1 ips and Hayman 1970). Fifty 

root segments ( 1 cm) from each sampled seed1 ing 

were evaluated for mycorrhizal colonization using 

the s1 ide method descrf bed by Kormanik and McGraw 

(19821. 

Site 1, located in Dubois County, IN, was 

classified as an old fteld in early stage 

succession, The soil was a well-drained? eroded 

phase sf a Zanesville silt loam (Typic Fragiudalf 

- fine silty, mixed mesic), which occurs 

extensively in the nonglaciated southern portion 

of the state. Site 2, classified as a marginal 

farmland site, was located in Tippecanoe County, 

IN. The soil was a somewhat poorly drained 

Fincastle silt loam (Aerie Ochraqualf - fine 

si 1 ty, mixed mesic) , which occurs throughout the 

glaciated portion of the state. 

Weather stations were established near each 

site and monthly precipitation and evaporation 

data were collected for the duration of the 

study. Avai 1 able water du rf ng the growing season 

was calculated for each site based on these 

weather stat ion data and moisture retention 

analyses. 

The sites were cleared of brush and woody 

vegetation (SlLe L) or cornstalks (Site 21, and 

di sked in Nove~rirber~ 1984, Cot;lpacti bf l ity of each 

soi 1 was detemf ned by applying surf ace pressures 

of 104, 242, and 380 kPa to sagnyles with 

i ncreasi ng molsture content and calcul at i ng the 

resulting bulk densities (Felt f965), 

A vibratory roller (380 kPa surface pressure) 

was used to apply two corapactisn treatments at 

each site in Aprdf, 1985. Different surface bulk 

densities were attained by varyfng the speed and 

vibration of the roller and the moisture content 

of the soil at ,he time that the treatments were 

applied. The dcsirsd surfcce bulk densities of 

Compaction Level L (Cell and Csnpacti on Level 2 

(CL2) were represenlat'lve of md.9um and highly 

compected condf %ions For tho mspective soils, 

based on compact%bility data, A noncompacted 

Sites were FsrtSlfzsd fn Aprf;, 1965 In a 

broadcast appl icazion to adjust -tho avai labie 

nutrient content -%o 140 kg ha nitrogen 

(NH4N0 ), 84 kg,ha phosphorus Is~perpkosphate)~ 

and 33% kg ha potassium (pnzcsh) . Chemlcal 

weed control (1.6 L glyphosate. 1 L digyat, 4.48 

kg oryzalinl and 1,12 kg simazine ha 1 was 

applied prs'or to planting and each site was 

treated as needed to mInSnJze root growth of 

weeds i n the pl ats, Seed1 ings were hand planted 

at each site in Apri 1, 1985, 

Soil medium from the upper 20 cm was used to 

determine partfcle sire distrtbutfon of each 

soil, A Uhland core sampler was used 50 collect 

so i 1 core samples from each conpacdi on treatment 

at 0-7.6, 7.6-15.2, 15.2-22,9$ and 22,9-30.5 cm 

depths. Bu7 k donsi ty so4 1 strength , water 

retention at -10 -0 , and -ioaWar available 

water holding capacity. and total and at r-f i 1 led 

porosity t8cre determined ZL cach depth for each 

compaction ireadmen%, Methods are cisscri bed i n 

Methods of SoSl Analysjs (Black 19651. 

Height and basal diameter were measured fn Mayp 

1985 and October, 1985, Based on these stem 

data, average seed1 ings Prom each 

compaction/mycorrhizae treatment were selected 

for possible root exc.r,tj nation, One randoiril y 

selected seedl ing ,of each species was excavated 

by hand from each compacLTon treatment (six 

seed1 i ngsls 5 te to determf ne hsrd zsnta l and 

vertical extent of root growth, in addition, one 

seedling of each specfes was randorqfy selected 

from each compacP;a"on/mycorrh4"zae treatment (18 

seed1 i ngslsite 1 for care sampl i ng, 

A hydraulic probe was used to collect soil core 

samples. Based on root dfstrSlbution of the 

excavated ~esdlings* cares were taken from radii 

of 22.9, 45.7* and 68,6 c1.i around each selected 

seed1 ing, Four cores werc taken ar each rddlus 

to a depth of 38,L crn, Each @ere was then 

divided into sections by dc;>th 18-7,69 7.6-15.2$ 

15.2-22.9, 22.9-38,5* 30,5-s8,%) and cores from 

the same depth were cembtncd for each radius, 

The hydropneumatfs el utr la-cion method sf Smucker 

et a1. (1982) was used to scparaxs and ccIfec-^L 

roots fro,; soil coresp and root ~e9gh-c~ Icng"clar 

and distribution were detert~ilned, Root 

subsamples were evaluated for mycsrrhlzal 

colonization as previous1 y dtscsibed, 

The study was established as a randomized 

comp1e"e block with Lreatmsr*Cs ai'i'anged m'n a 

spl it plot des r"gn (three ~iir~ipd~tj b:8 k$ea"&!bn7k~ 

two tree specs'es, three myc~rrh l zag treatr;rents 1 , 

Each site had rkree rep9 !cab< s~s ana 16 seed9 4 ngs 

in each conpa~t~oonl~ayc~rria~zae treatment plat. 

Stem data were analyzed by ~mai)sf s cf variance. 

Root data wcr; poalcc For iXyc0krhi zal treatments 

and analyzed b; anal: 51% 6'; varlafice and analysis 
of covariance, using original stem height and 

root collar diameter as covariates. Ranked means 

were analyzed by Duncan f s mu1 t ipl e range test. 

RESULTS AND DISCUSSION 

Although soils at both sites were classified as 

silt loams, soil from the upper 20 cm at Sfte 1 

had a higher proportion of sand and clay size 

particles (15 percent sand, 68 percent silt, 17 

percent clay) than Sfte 2 soil (5 percent sand, 

83 percent silt, 12 percent clay), and 

consequently, was more compactible (Fig. l), 

When soil from Site 1 was subjected to 104 kPa 

surface pqssure, bulk density increased f ran 

1.30 Mg m at a so13 moisture content of 15 

percent to 1.42 Mg m at a moisture content of 

30 percent (Fig. 1). Similarly,.3bulk densities 

increased to 1.49 and 1.53 Ng m when samples 

were subjected to surface pressures of 242 and 

380 kPa, respectively. The soil moisture content 

where maximum bulk densitfes were obtained with 

these pressures was approximately 25 percent. 

Site 1 

Bulk densities of soil samples+ from Site 2 

increased from 1.39 to 1.60 Mg m at a moisture 

content of 23 percent when subjected to a ground 

pressure of 104 kPa (Fig. I), When 242 and 380 

kPa ground pressures were ~sed~~maxlmum bulk 

densities of 1.69 and 1.74 Mg m , respectively, 

were obtained at a moisture content of 

approxfmatel y 19 percent, 

The surface (0-7.6 cm) bulk density of the 

noncqpacted CON at Site 1 was approximately 1.15 

Ng m (Fig, 2). At the 7.6-15.2 and 15.2-22.9 

cm depths. _tlk densfty increased to 1.33 and 

1.40 Mg m , respectively. Based on 

conpactibility data* the desired sjurface bulk 

densitfes were 1.30 and 1.50 Mg m- for CLL and 

CL2, respectively . Average su ysace bu 1 k 

densities_tttalned were 1.30 Mg m for CL1 and 

1.35 Mg m for CL2. At depths exceeding 7-6 cm, 

bulk densities were not signf f icantl y increased 

for either compaction treatment. The soil 

moisture content was approximately 15 percent 

when CL1 was applied and 25 percent when CL2 was 

applied. However, surface bulk densities 

attai ned were lower than anticipated based on 

compactibilfty data. 

'" t Site 2 

Soil Moisture Content (percent) 

Figure 1,--Bulk densities obtained for soil samples (0-20 cm) from Site 1 and Site 2 subjected to 

ground pressures of 104,. 242, and 380 kPa at sol 1 moi sture contents rangi ng from 10 to 35 percent. 
Site 1 Site 2 

Cornpac tion Treatment 

Figure 2.--Average bulk density for Control (CON), Compactf cn level 1 

(CLL), anls action Level 2 !CL reetnents at 0-7.6 cm 

7.6-15.2 cm and 15.2-22 -9 cm depths at Site 1 and Si 

The noncotnpacted (CJJN) surface bulk density at 

Si$e 2 was 1.33 Mg m . and increa ed to 1.38 Mg 

m at 7.6-15.2 cm, and 1.43 Mgm-'at 15.2-22.9 

cm depths (Fig. 21. To enable comparison of 

seed1 ing root responses between sites, the 

desired surface bulk deyities for CL1 and CLZ 

were 1.45 and 1.55 Mg m , respectively, although 

this soil was more compactible than Site 1 soil, 

Average surface bulk densities att ined for CLI 

and CL2 were 1.47 and 1.5C I4g m-'* at soil 

moisture contents of 10 and 20 percent, 

respectively. At depths exceeding 7.6 c-9 the 

bulk density was approximately 1.43 Mg rn for 

both compaction treatments. 

Total and ai r-f i 1 led porosi ty decreased 

linearly with increasing bulk densfty at each 

site. Total porosity decrezsed from 

approximately 57 p-qcent on the CON (bulk 

density = 1.15 Mg FII to 51 percent at CLl (bulk 

density = 1.30 Mg rn-$1 a?mJ 50 percent at CL2 

(bulk density = 1.35 Mg m 1 on Site 1 (Fdg, 31. 

Air-filled porosity decreased from 18 percent for 

noncompacted soils ro 12 percent a% the highest 

compaction level on Si"c 1 when soil hloisture 

potent la1 was maintained near field capacity 

(-lOkPaf, At Site 2, total porosity decreased 

from approximately -5p percent on the CON (bulk 

density = 1.33 Mg m -5 to 45 percent at CL2 (bulk 

density = 1.58 Mg m 1 (Fig. 3). Air-filled 

porosity dccrcased from 15 percent an the CON to 

5 percent at CL2 when soil noisture potential was 

-1okPa. Afr-filled porosity rrt soil moisture 

potentials of-6Oand-roo k~a decreased stmilarly at 

each site. 

Based on water retent ion analyses, the total 

available water holding capacita for both sites 

was approximately 0.12 cm cm (Fig. 41. 

However, because of low amounts of precipitation 

at Site 2 (June-October), the actual available 

water at this site was lower than at Site 1, and 

a rater deficit existed during much ef the 

growing season at this site. 

Approximately 30 percent of ye1 1 ow-pop1 ar and 

sweetyum lateral roots sampled were colonized by 

G. macrocarpua or fi. fn;cfculatum when inoculated 

seed1 i ngs were 1 i fted f som nursery seedbeds. 

Roots of non i nocul ated seed1 i ngs were not 

colonized at this time. However, at the end of 

the fi rst growing season, rriycorrhizal 

colonization did not differ s1gnifican"r;y for 

inoculated and nonfnoculated seedlings at either 

sfte. Consequently, root growth was not 

significantly Influenced by mycorrhizal 

treatment. 

At Site 1, length and weight of yellow-poplar 

roots decreased significantly as compaction 

increased fran CL1 to CL2 or as yrface bulk 

density increased above 1.30 Mg m (Table I). 

Length and weight of sweetgum roots varied. At 

Site 2, root length and weight of both species 

decreased significantly as cootpaction increased 

from CON to CLl or as surface-julk density 

increased front 1.33 to 1.47 Mg rn . 
Site 2 

Bulk Density (Mg K~) 

Figure 3.--Total poro ity and air-fllled porosicy at-20 -wand-looW*p.at bulk densities rangin, 

from 1.1 to 1.6 Mg rn-3 for Site 1 and Site 2 soil. 

-0.zlt I I 1 I I L 

May Jun Jul A Sep Oct Nov 

Month 

Figure 4.--Available wzcer holding capacity (AWHC) 

and available water at Site 1 and Site 2 for 

May-November , 1985. 
Table 1.--Length and sven-dry weight sf cored yellow-poplar and sweetgum. 

roots on Control (CON1, Co:spaction Level 1 (CLlI1 and CompactJon Level 2 

fCt2) at Size I and Site 2, 

Site 1 

CON CL 1 GL2 CON CL I CL 2 

Yell ow-Popl ar 

Length kcm) 495aa 491a 95b 193a 63b 2b 

Weigh"ig1 1.15a 1.39a 0,30b 0.58a 0.14b 0.01~ 

Sweetgum 

Length (cm) 663 a 112b 887a 533a 82b 17 8ab 

Weight (g) 0.82b 0.12b 2,42a 2.18a 0.19b 0.39b 

a~ow values for each site followed by different letters are significantly 

different at P = 0.01. 

A1 though trends were simi 1 ar for both species 

at Site 2, root length and weight of sweetgum 

were greater than yellow-poplar on each 

compaction treatment. These differences in 

species may be attributable to differences in 

morphology of the root systelns. The fibrous 

lateral roots of sweetgum were able to penetrate 

more extensively into the soil profile than the 

coarse lateral roots characteristic of 

ye1 1 ow-pop1 ar. 

Horizontal root extension, as determined by 

length and weightof roots occurring in soil 

cores taken at each radius and totalled for all 

depths? was affected similarly by compaction. At 

Site 1 ye1 1 ow-pop1 ar roots extended 1 ateral ly to 

68.6 cm on the CON and CLl, but extension was 

restricted to a radius of 45.7 crn on CL2 

(Table 2). 

Horizontal growth of sweetgum roots varied, 

with greatest lateral extension occurring on CL2. 

At Site 2, no roots of either species extended 

laterally past a radtus of 45.7 crn (Table 3). 

Roots of both species were restricted to 22.9 cm 

or less on CL1 and CL2 treatments. 

At Site I, vertical extension of yellow-poplar 

roots, as determined by length and weight of 

roots occurring in soil cores taken at each depth 

and totalled for all radii, decreased 

signif icantly as contpaction increased from Cbl to 

CL2 for depths to 22.9 crn (Table 41. Although no 

significant differences occurred below thi s 

do3th, roots were absent from the 30.5-38.1 cm 

depth on CL2. Vertical extension of sweetgum 

roots vari ed at this site. 

At Site 2, roots of both species were absent or 

extremely limited in the surface (0-7.6 cm) cores 

for all treatments (Table 5). For both species, 

root length and weight at '&he 7.6-30.5 cm depths 

decreased significantly as compaction increased 

f ronl CON to CLI. 

D i f f erences in root responses between sites 

were due primarily to differences in soil 

moisture content. Because a water deficit 

existed at Site 2 for much of the growing season? 

seed1 ings were subjected to water stress. In 

addition, drier soil conditions and higher bulk 

densities at Site 2 resulted in greater soil 

strength, although this property was variable at 

each site. 

At Site 1, horizontal extension of 

ye1 low-poplar roots within the surface layer was 

probably limited by increased soil strength 

associated with higher bulk densities on CL2. At 

Site 2, root growth near the surface was 1 imited 

by dry soil conditions on a11 treatments. At 

higher compaction levels, roots were further 

limited by a combination of increased bulk 

density and strength. 

Although compaction did not significantly 

increase bulk densities at depths exceeding 7.6 

cni, vertical root extension was influenced by 

conpaction at depths to 38.1 cm, This could have 

been due to reduced ai r-fil led porosity of tho 

compacted surface layer, which would have 

decreased 0 and C0 diffusion rates to and frohi 

the roots a$ lower $ePths. 

SUMMARY 

With the exception of sweetgum at Site I, 

seedling root responses at both sites were 

similar: increasing surf ce bulk densities above 

approxiroately 1.30 Mg rn-' resulted in reduced 

growth and lirnfted dfstribution, and mycorrhizal 

inoculation had no effect on responses. 

Generally, total root length and weight were 

greater and distribution was more extensive for 

sweetgum seed1 ings, due to the fibrosity of the 

root system, 
Table 2,--Length and oven-dry weight of cored yellow-poplar and sweatgum 

roots by radius (totalled for all depths) for Control (CON), Cmpaction 

Level 1 (CL1lB and Compaction Level 2 (CL.2) at Site 1. 

Rad i us 

GON 

Length Weight 

A 

Length Weight 

A 

Length Weight 

(cm) (cm) (g) (cm) (g (cm) fg) 

Sweetgum 

"ROW values for each root parameter foll owed by different letters are 

significantly different at P = 0.01. 

Table 3 .--Length and oven-dry we1 ght of cored ye1 1 ow-pop1 ar and sweetgum 

roots by radius (totalled for all depths) for Control (CON)# Compaction 

Level 1 (CLl), and Compaction Level 2 (CL2) at Site 2. 

Radius Length 

CON 

Weight 

CL1 

Length Weight 

CL2 

Length Weight 

(em) (cm (g) (cm) (g) (cm) (g) 

Sweetgum 

a~ow values for each root parameter followed by different letter5 are 

signiff~antly different at P = 0.01. 
Table 4.--Length and oven-dry weight of cored yellow-poplar and sweetgum 

roots by depth (totalled for all radii) for Control (CON), Compaction 

Level 1 (CLl), and Compaction Level 2 (CL2) at SSte 1. 

Depth LenghLh 

CON 

Weight 

ALength Wei ght A 

Length Weight 

(cm 1 (cm (g) (cm (g) (cm) (g 

Sweetgum 

a~ow values for each root parameter followed by different letters are significantly different at P = 0.01. 

Table 5.--Length and oven-dry weight of cored yellow-poplar and sweetgum 

roots by depth (totalled for all radii) for Control (CON), Compaction 

Level 1 (CLl), and Compaction Level 2 (CL2) at Site 2. 

Depth Length 

..CQN 

Weight 

CL1 

Length Weight 

ALength Weight 

(cm) (cm) (g) (cm (g) (cm) (g) 

0-7.6 3aa 0.01a Oa 0 .OOa 0 a 0. OOa 

7.6-15.2 27 a 0.13a Ob 0 .OOb 2b 0.01b 

15 -2-22-9 95a 0.26a 7b 0.01b Ob O.OOb 

22.9-30 -5 43 a O.lla 22b 0.02b Ob 0 .OOb 

30.5-38.1 25a 0.08a 3 2a O.lla Oa 0 .OOa 

Sweetgum 

a~~~ values for each root parameter followed by different letters are sjgnificantly diffor2nt ac P = 0.01. 
Although both sites had similar available water 

holding capacities, the actual available water at 

Site 1 was higher than at Site 2. A water 

deficit occurred for only two months during the 

growing season at Site 1. In contrast, a water 

deficit existed from mid-June to mid-October at 

Site 2, 

The relatively high soil moisture content at 

Site 1 minimized compaction effects on this site. 

Although variable, resistance was lower at Site 1 

than Sfte 2 on all compaction treatments, In 

addition, bulk densities were lower and total and 

air-filled porosities were higher at Site 1. In 

contrast, seed1 ings at Site 2 were under water 

stress during most of the growing season, and 

bulk density and soil resistance were high. 

During the limited time that soil moisture 

potential at Site 2 was at field capacity, 

ai r-fi 11 ed porosi ty was near or be1 ow 10 percent, 

the level considered by many to be limiting to 

plant growth. Consequently, seed1 ings at Sfte 1 

had greater root growth responses than those at 

Site 2, 

LITERATURE CITED 

Black, C.A. (ed.). Methods of Soil Analysis, Part 

I, ASA Monograph No. 9; Am. Soc. Agron.; 

Madison, WI; 1965, 

Bryan, W.C.; Kormanik, P.P. Mycorrhizae benefit 

survival and growth of sweetgum seedlings in 

the nursery. So. J . Appl . For, 1: 21-23 ; 1977. 

Clark, F.B. Endotrophic mycorrhizae influence 

ye1 1 ow-pop1 ar seed1 i ng growth. Sc fence 

140: 1220-1223; 1963. 

Felt, E.J. Compactibility. In: Black, C.A., ed. 

Methods of soil analysis, Part I, ASA Monograph 

No. 9; Am. Soc. Agron.; Madison, WI; 

1965:400-412. 

Froelich, H,A. Soil compaction from logging 

equipment: effects on growth of young ponderosa 

pfne, J. Soil and Water Conser. 34:276-278; 

1979. 

Gray, L,E.; Gerdemann, J.W. Influence of 

vesicular-arbuscul ar mycorrhi zas on the uptake 

of phosphorus-32 by Liriodendron ZgJi~ifet-4 and 

J iauf dambar . Nature 213:106-107; 

1967. 

Hatchell, G.E.; Ralston, C.W.; Foil, R.R. Soil 

disturbance in logging: effects on soil 

characteristics and growth of loblolly pine in 

the Atlantic Coastal Plain. J, For. 68:772-775; 

1970. 

Kormanik, P.P.; Bryan, W.C.; Schultz, R.C. 

Influence of endomycorrhizae ~rtl growth of 

sweetgum seed1 i ngs f rorn ci $h"cmoi;t;cr trees. 

For, Sci . 23 : 500-506; 1977. 

Kormanik, POP.; McGraw, A.C. Quantification of 

vesicular-arbuscular mycorrhizae in plant 

roots. In: Schenck, N.C., ed. hthods and 

principles of mycorrhizal research; American 

Phytopathological Society; St. Paula MN; 

1982:37-45. 

Kormanik, P.P.; Schultz, R,C.; Bryan, W.C. The 

infl uence of vesicul ar-arbuscul ar mycorrhi zae 

on the growth and development of eight hardwood 

tree species. For. Sci . 28: 53 1-539; 1982. 

Kreh, R.E.; Burger, J,A,; Torbert, J.L. Soil 

compaction front tracked and rubber-tired 

tractors and its influence on seedling survival 

and growth, In: Shoulders, E., ed. Thira 

biennial southern si1vicultura1 conference; 

Atlanta, GA; Nov. 7-8; 1984:327-330. 

Lockaby, B.G.; Vidrine, C.G. Effect of logging 

equipment traffic on soil density and growth 

and survfval of young loblolly pine. So. J. 

Appl. For. 8(2):109-112; 1984. 

Menge, J.A.; Timmer, L.W. Procedures for 

inocul ation with vesicul ar-arbuscul ar 

mycorrhizae in the laboratory, greenhouse, and 

field. In: Schenck, N.C., ed, Methods and 

principles of mycorrhizal research; American 

Phytopathological Society; St. Paul, MN; 

1982: 59-68. 

Mitchell, M.L.; Hassan, A.E.; Davey, C.B.; 

Gregory, J.D. Loblolly pfne growth in compacted 

greenhouse soils. Trans. ASAE 25:304-307, 312; 

1982. 

Phillips, J.M.; Hayman, D.S. Improved procedures 

for clearing roots and staining parasitic and 

vesicular-arbuscular mycorrhizal fungi for 

rapid assessment of infection. Trans. Br . Mycol . Soc. 55 : 158-162; 1970. 

Pope, P.E. Influence of &lornus fascicu1W 

mycorrhizae on some physical and chemical 

characteri st ics of QCC idental f s 

seedl ings. Can. J . kt. 58: 1601-1606; 1980. 

Pope, P.E. ; Hol t, H.A. Paraquat influences 

development and efficacy of the mycorrhizal 

fungus Slomus . Can. J. kt. 

59: 518-521; 1981. 

Pope, P.E.; Chaney, W.R.; Rhodes, J.D.; Woodhead, 

S.H. The mycorrhizal dependency of four 

hardwood tree species. Can. J. Bot, 61:412-417; 

1983, 

Sands, R.; Greacen, E.L.; Gerard, C.J. Compaction 

of sandy soils in radiata pine forests. I. A 

penetrometer study. Aust. J. Soil Res, 

17:lOl-113; 1979. 

Schultz, ROC.; Kormanik, P.P.; Bryan, W.C. 

Effects of fertilization and vesiculararbuscul ar mycorrhizal inoculatf on on growth of 

hardwood seedlings. Soil Sci. Soc. Am. J. 

45 : 961-965; 1981. 
Slmons, G.L.; Ezell, A.W, Root #eveIopmftnt of 

loblolly seedlings in compacted sofls, In: 

Jones, E,P.r ed, Second biennfal southern 

silvfcultural conference; Atlanta, GA; Nov. 

4-5 ; 1982: 26-29. 

Smucker, A.J.M.; McBurney~ S.L.; Srfvastava, A,E. 

QIantitatfve separation of roots from compacted 

soil profiles by the hydropneumatic elutrlatfon 

system. Agron. J . 74: 500-503; 1982. 

South, 0, Artiffclal lnoculatfon of fumfgated 

nursery beds w i th endomycorrh i zae . Tree 

Planter @s Notes 31:3-5; 1977. 

Wert, S.; Thomas, B.R. Effects of skfd roads on 

diameter, heightr and volume growth in 

douglas-ffr, Soil Sci. Soc. her. J, 

45:629432; 1981. 
PINE GROWTH IMPKOVEmNT ON LOGGING SITES 

WITIi SITE PmPAIIATIOX MiII FERTILIZATION' 

W, H. McKee and G. E. ~atchell' 

Abstract,--Tree-length logging with rubber-tired skidders 

suppressed volume growth of individual planted pines in the 

succeeding stand through age 12. Treatments tested for alleviating the site damage on the poorly drained Batheria soil 

were flat disking and bedding, in combination with 200-50-100 

fertilizer, a 400-135-175 fertilizer and 15 tons of sawdust 

per acre, or no amendments. Survival at age 12 was not 

altered by logging but was reduced by fertilization due to 

self-thinning. Adverse effects of logging were mitigated by 

bedding or the lower fertilization treatment at age 12 in 

terms of tree heights and volume per acre, The higher fertilizer level did not cause a further increase in growth. 

Results to date suggest that fertilization of poorly drained 

sites is an inexpensive means of alleviating damage done by 

logging. If the area has been fertilized, bedding in addition to fertilization does not appear to add substantially to 

loblolly pine growth on this site. 

INTRODUCTION 

Rubber-tired skidding of timber on Atlantic 

Coastal Plain sites can puddle and compact wet 

soils. As a result, growth of loblolly pine 

seedlings planted on skid trails and log decks or 

landings is usually poor compared to that on the 

unaffected areas (Foil and Ralston 1967, Hatchell 

1970, Hatchell and et al. 1970, Hatchell 1981). 

Skidding on medium- to fine-textured soils usually 

reduce? macropore space, and compaction is 

greatest when soil is moderately moist. When 

moisture is near saturation, skidders cause 

puddling (deformation of soil structure by plastic 

flow). Scraping of the forest floor and surface 

mineral soil has the potential ~f removing 

nutrients from skid trails and landings, further 

retarding tree growth, Since skid trails and log 

landings often cover a substantial proportion of a 

logged area, the loss in growth of the new stand 

to compaction and puddling or scraping of the surf ace can be considerable. 

In the study reported here growth of planted 

loblolly pines on a clearcut area was observed for 

12 years. Prior to planting, skid trails and a 

lag deck were prepared in several ways and soil 

Paper presented to the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6,1986. 

2 The authors are Soil Scientist , Southeas tern 

Forest Experiment Station, Forestry Sciences 

Laboratory, 2730 Savannah Highway, Charleston, SC, 

29407 and Research Forester, Southeastern Forest 

Experiment Station, Forestry Sciences Laboratory, 

Carlton Street, Athens, GA, 30602. 

amendments were added to determine if cultural 

treatments could alleviate adverse effects of 

logging operations. 

METHODS AND MATERIALS 

Study Area 

The study was conducted on a 30-acre clearcut on 

the Santee Experimental Forest, near Charleston, 

South Carolina. The soil series is Beathera, 

which is a member of the clayey, mixed thermic 

family of Typic Palearfuults. Beathera is classed 

as poorly drained and occurs on nearly flat land 

with low topographic position. The topsoil is 

loam or silt loam about 6 inches deep, and the 

subsoil is sandy clay. Soil samples collected 

from the surface 6 inches contained an average of 

7 percent organic matter and had a pH of 4.2. 

A well-stocked stand dominated by loblolly pine 

was clearcut for sawtimber during the.summer of 

1972, and logs were transported to a landing with 

an articulated rubber-tired skidder. The area was 

burned during the spring of 1972 to facilitate 

timber marking and to reduce competition from 

hardwoods and shrubs, A log landing and a network of primary skid trails converging at the log 

landing were laid out in advance of logging. 

Although rainfall was unseasontbly low during 

logging, the soil retained a moderately high 

rloisture content because of its low topographic 

position and high moisture-holding capacity. 

Rubber-tired skidders formed ruts in primary 

skid trails averaging 5 inches deep and shoulders 

of ruts 4 inches high (each measured from soil 

surface). The depth of ruts is typical for 

logging under moderately moist conditions, kuts 
formed on similar soils under wet logging conditions are comonly 1 to 2 feet deep. More than 

10 trips with the skidders caused severe soil compaction. Pleasurements taken with a pocket 

peaietrometer indicated that average soil strength 

or hardness on primary skid trails often exceeded 

64 pounds per square inch and averaged three times 

greater on the primary skid trails than on uncompacted soil, 

Treatments and Ex~erimentai Desien 

A split-plot experiment was established on a 

clearcut after tree-length logging with rubbertired skidders. Combinations of soil-compaction 

arid site-preparation treatraents were tested on Y7 L.~~o~ - plots, which were replicated twice in randomized complete blocks, hounts of fertilizer 

and an organic amendment were tested on subplots, 

Each block contained three major plots for testing 

randomly assigned site-prepziration treatments, 

The plots were located on compacted soil in portions of prin~ary skid trails and three were 

located nearby on uncompacted soil, Major plots 

measuring 30 by 198 feet were divided into three 

subplots, each 30 feet by 66 feet, or approximately 0.G5 acre. 

The three site-preparatiora treatments were: 

(I) spraying woody vegetation , IL~I herbicide 

during summer of 1972 but no meclranical site preparation (herbicide), (2) shearing trees at ground 

line, rootraking debris into windrows, and flat 

disking (disking), ancl (3) shearing trees at 

ground line, root raking debrit into windrows, and 

then preparing beds at 10-foot intervals 

(bedding), A11 r~echanical treatments were 

completed in late fall 1972, wi~erl soil moisture 

was ideal for tilling, Two trips were made with 

the bedding machine on both uncampacted soil and 

compacted soil; the second trip was needed in the 

center of the skid trails to penetrate the hard, 

compacted soil. Bed elevation averaged allproximately I foot above the original elevation, and the 

depth of trllage averaged 6 inches. Plots schecluitd for flat disking were triple disked to a 

aepth oL 5 inches, 

Each major plot was divided into three subplots 

and randoi,dy assigned the followir~g amounts of 

fertilizer and organic amendment: (I) unfertilized 

~i~~ltlr;; (2) medium level of fertilizer-200 pounds 

oL nitrogen (N) as ureaformaldehyde, 50 pounds of 

ele;.ental phosphorus (P) as triple superphosphate, 

arid 100 pounds of elemental potassium (K) as 

rnuriate of potash per acre (medium level of fertii~zer); and (3) 400 pounds of 3, 175 pounds of 

P, 2nd 175 pounds of K, in the above forms, plus a 

3i4-inch iiei,tl? of sawdust , which mounted to 15 

toils oE oven-ciry sar~riust per acre (high level of 

ferli iizr*u), Ureaformaldehyde, a reltr ively 

expensive, slow-release form of nitrogen, was 

selected prirldrily to assure an adequate amount of 

slowly available nitrogen for breakdown of sawdust 

bec~use nitrogen deficiency after sawdust application tias been shown to persist for .nore than a 

y'ar (Bollen and Lu 1957), Fertilizer artd sawdust 

bcre broacicast and were mixed with soil during 

f :at tilskint, and bedding. 

The treatments described above were also randomly assigned and installed on a single block on 

a log landing, Since treatments could not be 

installed on uncompacted soil nearby, data 

collected on the log landing were not statistically analyzed, 

Loblolly pine seedlings were hand planted during 

March 1973, Three rows of seedlings were planted 

with 10-foot spacing between rows and 2-foot 

spacing along rows, initially providing 99 

seedlings per subplot (2,178 trees per acre), On 

skid-trail plots, the central axis was oriented 

with the middle of the trail, and a row of 

seedlings was planted between a pair of ruts on 

soil compacted by skidding logs, 

Diameters at breast height (dbh) and heights of 

all trees were measured at the end of the twelfth 

growing season, Total stemwood volume (outside 

bark) was computed using the equations of Clutter 

et. al, (1984). Border effects on adjacent 

subplots due to application of different amounts 

of fertilizer and sawdust were not obvious, so 

values for all trees on each sublet were included 

in the analyses, 

Analyses of variance (ANOVA) were based on all 

trees in the subplots and on the 12 largest trees 

per subplot (crop trees). These crop trees can be 

expected to form the dominant stand in the next 5 

to 10 years, Treatment means and interactions 

were anaylzed for statistical significant difference using Duncan's Multiple Range Test at P = 

0.05, 

RES ULTS 

Survival 

Site preparation and fertilizer application 

affected survival of loblolly pine seedlings from 

the first through the fourth growing season 

(Hatchell 1981), but soil compaction during 

logging did not. Mortality was highest during the 

first growing season and least during the fourth 

growing season. Grasses and herbs were 3 to 6 

feet tall during the first year, and competition 

tm them appeared to cause most of the mortality. 

hanical site preparation increased pine surapparently by reducing compe t it iori during 

set establishment, but fertilizer application 

at r-dntlng time reduced survival, probably by 

ilkcreasing competition from grasses and herbs. 

Negligible mortality was attributed to insects, 

Fusiforrn rust infections were present on an 

average of 13 percent of the sterns, hut less thaii 

1 percent of all seedlings were killec' by th~s 

disease, Treatments did not significantly affect 

the incidence of fusiform rust on stems, 

A similar treataent effect on survival relationship was observed at age 12. At that time, 

survival by site-preparation treatment was 75% for 

bedding, 64% for disking and 53% for herbicide, 

The differences were statistically significant. 

Aiso, survival with zero fertilizer (77%) was 

significantly higher than survival with medium 

(60%) or high (55%) fertilizer amendments. 
Growth 

The logging-disturbsnce x site-preparation x 

fertilizer interaction was not significant for any 

growth parameter, and the site-preparation x fertilizer interaction was significant only for 

height of all trees on plots (Table 1). 

Therefore, growth response is tabulated for the 

main effects of the three factors and for the 

logging disturbance x site-grepartion interaction 

and the logging disturbance x fertilizer interaction (Tables 2 through 5). 

Height 

Average height of all trees and crop trees were 

increased by 6 to 10 percent by bedding (Table 2). 

Disking offered no improvement over the herbicide 

alone. Soil compaction did not affect tree 

heights. No improvement in height was found with 

the heavy compared to the medium fertilizer application. Fertilizer increased heights of all trees 

in plots receiving herbicide and disking treatments by 27 to 47 percent, Fertilizer did not 

improve tree heights in combination with bedding. 

Fertilizer at the medium level increased tree 

heights of all trees by 4.7 feet on uncompacted 

soil, but had no significant effect on crop trees 

growing on uncompacted soil. On the compacted skid 

trails, the medium fertilizer treatment increased 

heights by 9.1 feet for all trees and 6.6 feet for 

crop trees. Soil compaction reduced heights 

without fertilizer both for all trees and for crop 

trees, but it had no effect with the fertilizer 

treatments. 

Average dbh for all trees in stand or for crop 

trees was unaffected by site-preparation treatments (Table 3). Fertililzer application 

increased dbh of aL1 trees by 33 to 36 percent. 

Compaction reduced dbh of all trees, Overall 

means were 4.14 and 3.85 inches for the uncompacted vs. compacted sites. Diameters of crop 

trees on uncompacted plots were not improved with 

fertilizer, but on the compacted skid trail fertilizer increased diameter by 20 to 29 percent, 

Basal Area 

Soil compaction did not affect the total bassi 

area of all trees in the stand, but bedding 

increased basal area by 27 to 37 percent compared 

to overall for disking and herbicide treatments, 

respectively (Table 4). Site preparation dld not 

affect basal area of crop trees, which indicates 

that survival did not interact with diameter 

growth. Fertilizer applications increased basal 

area of all trees about 56 percent when soil was 

compacted but had no effect on uncompacted soil. 

Fertilizer increased basal area of crop trees by 

29 to 40 percent regardless of compaction treatments which showed no significant effect. 

TABLE 1. Significance levels of main effects and interaction of site-preparation and fertilizer treetments and logging disturbance based on ANOVA'S of 

height, diameter breast high, basal area, and stemwood volume of all trees 

and crop trees of 12-year old loblolly pine. 

DISTURB 

SITEPREP ,024 .I96 ,001 .001 ,033 -637 .470 .882 

DISTURB x SITEPREP .726 .682 .145 .226 226 .340 ,399 a335 

FERT ,001 o00l .I05 -017 e001 '001 ,001 -001 

DISTURB x FEKT .008 .257 ,044 .051 .003 .044 -075 .041 

DISTURB x 

SITEPREP x FERT 

- 1lDISTURB = logging, disturbance; SITEPREP = site preparation; FEKT = fertilizer 
Table ?.--Height of all trees in stand and of crop trees at age 12, by sitepreparation and ferti lizer treatments and classes of logging disturbance. 

f reatnents 

I soi 1 1 soi 1 soi 1 

Height of all trees in stand 

Uncompacted Compacted 

I I 

-------------------------Feet-'----------------------- 

Site Preparation 

Herbi ci de 34.2 bg/ 33.6b 42.66 43.2b 

Disking 33.5b 31.7b 40.8b 42.2b 

Beddi na 37. la 36.9a 45.4a 45.2a 

Height of crop trees 

Uncompacted Compacted 

Fert i li zer 

Zero 

Medi um 

High 

Means, logging 

- l/Means for loggi ng-disturbance classes with an underscore are not significantly 

different at P = 0.05. 

- 2/Means for the site-preparation x logging-disturbance interaction or for the 

fertilizer x logging-disturbance interaction followed by a common lowercase 

'letter are not significantly different at P = 0,05. 

Table 3.--Diameter breast height of all trees in stand and of crop trees at age 

12, by site-preparation and ferti lizer treatments and classes of logging disturbance. 

Treatments 

I I 

....................... Inches'----------------------- 

Site preparation 

Dbh of all trees in stand 

Uncompacted Compacted 

soi 1 soi 1 

Herbi ci de 4.24a2-/ 3.92a 

Disked 4.03a 3.67a 

Bedded 4.16a 4.00a 

- Dbh of crop trees 

Uncompacted Compacted 

soi 1 soi 1 

Fert i li zer 

Zero 3.52b 2.99b 

Me di um 4.38a 4.27a 

High 4.52a 4.32a 

Means, loggi ng 

disturbancel/ 4. 14 

- 1/Means for loggi ng-di sturbance classes with an underscore are not significantly 

different at P = 0.05, 

- 2/Means for the si te-preparation x logging-disturbance interaction or for the 

fertilizer x logging-disturbance interaction followed by a common lowercase 

letter are not significantly different at P = 0.05. 
Table 4.--Basal area of a11 trees in stand and of crop trees at age 12, by 

si te-preparation and ferti li zer treatments and classes of logging disturbance. 

----..--- 2 (Feet) per acre-------- 

Site preparation 

Herbi ci de 116,lb2/ 

Di sked 135.3bBedded 163.2a 

Basal area of crop trees 

Uncompacted Compacted 

soi 1 soi 1 

Treatments 

Ferti li zer 

Zero 141.9a 

Medi um 138.9a 

High 134.0a 

Basal area of all trees in stand 

Uncompacted Compacted 

soi 1 soi 1 

Means, logging 

di sturbancey 138.3 

- l/Means for loggi ng- di sturbance classes with an underscore are not si gni fi cant ly 

different at fl = 0.05. 

- 2lMeans for the si te-preparati on x logging- disturbance interaction or for the 

ferti li zer x loggi ng-di sturbance interaction followed by a common lowercase 

letter are not significantly different at = 0.05. 

Table 5. Stemwood volume of a11 trees in stand and of crop trees at age 12, by sitepreparation and ferti li zer treatments and classes of logging di sturbance. 

3 ----- (Feet ) per acre----- 

Site preparation 

Herbicide 1,645b2/ 1,724b 

Disked 1,934b- 1,6966 

Bedded 2,427a 2,377a 

Volume of crop trees 

Uncompacted Compacted 

soi 1 soi 1 

Treatments 

Ferti li zer 

Zero 1,924b 1,2 15b 

Me di urn 2,063a 2,22 la 

High 2,019a 2,362a 

Volume of all trees in stand 

Uncompacted Compacted 

soi 1 soi 1 

Means, loggi ng 

di sturbanceL/ 2,002 1,932 - 889 - 82 7 

- l/Means for loggi ng-di sturbance classes with an underscore are not si gni fi cant ly 

different at fl = 0.05. 

- 2/Means for the si te-preparation x loggi ng-disturbance interaction or for the 

ferti li zer x loggi ng-disturbance interaction followed by a common lowercase 

letter are not significantly different at fl = 0.05. 
Volume 

Total stemwood volume of all trees on plots was 

increased 32 to 43 percent with bedding compared 

to disking and herbicide application, respectively, irrespective of soil compaction (Table 5). 

Bedding had no significant effect on volume for 

crop trees. Fertilizer at the medium or high 

level increased stem wood volume by 572 to 620 

cubic £set per acre for all trees in the stand and 

255 to 35"ubic feet per acre for crop trees with 

or without compaction. 

Responses on the hgging Deck 

Results of the single replication on the log 

landing are not presented in the tables but are 

similar to those on the skid trails. For crop 

trees, heights averaged 46.2, 40.7 and 45.2 feet 

and d.b.h. averaged 6.42, 5.09 and 5.71 inches, 

respectively, for herbicide, disking and bedding. 

Crop trees averaged 39.2, 47.1 and 45.9 feet tall 

and 4.88, 6.11 and 6.23 inches in diameter at 

d.b.h. for the zero, medium and high fertilizer 

treatments. 

DISCUSSION AND CONCLUSIONS 

Since trees were planted 2 feet apart in 

rows, crowding and self-thinning have affected 

average heights, diameters, and survival. For 

this reason the crop trees represent growth of 

trees which can be expected to have commercial 

value in 5 to 10 years. Whether one looks at 

basal area or total volume per acre of all trees 

or crop trees, there was no response to disking 

alone or to fertilization at a quantity greater 

than the medium treatment. 

Bedding significantly improved tree height, 

stand basal area, and stem volume of all trees, 

but only increased height growth of crop trees. 

The medium level of fertilizer effectively 

increased growth variables for all trees on the 

plot as well as those designated as crop trees. 

Height growth, average dbh, and total volume of 

crop trees were increased on compacted soil by the 

medium fertilizer treatment, but fertilizer did 

not improve growth on the area not disturbed by 

logging. This observation further supports the 

hypothesis that skidding operations remove topsoil 

and thus lower fertility and adversely impact 

marginally fertile loblolly pine sites. Another 

conclusion that can be gained from these data is 

that with dense planting as done in this study on the 

disturbed areas the higher fertility keeps the stand 

from stagnating and accelerates growth of dominate 

trees. It can be concluded that either bedding, 

which concentrates nutrients in the planting row, or 

fertilizer application will mii gate growth losses on 

skid trails. 

Findings appear to have changed little since 

results were reported at age 4. Then as now, most of 

the growth response was to bedding and the medium 

fertilizer treatment (Hatchell 1981). The results 

further support the conclusion that bedding or application of a moderate level of fertilizer is effective 

in restoring growth losses on areas disturbed by 

logging. Where facilities and capital are limited, 

broadcasting fertilizer over the disturbed areas is 

effective in restoring site productivity. 

LITERATURE CITED 

Bollen, W. B. and K. C. Lu. Effect of Douglas-fir 

sawdust mulches and incorporations on microbial 

activities and plant growth. Soil Science 

Society of America Proceedings; 1957; 21:34-41. 

Clutter, J. L.; W. R. Harms; G. H. Brister; and J. 

W. Rheney. Stand structure and yields of siteprepared loblolly pine plantations in the lower 

Coastal Plain of the Carolinas, Georgia and North 

Florida. USDA Southeastern Forest Experiment 

Station, Asheville, NC; 1984; 173 p. 

Foil, R. R. and C. W. Ralston. The establishment 

and growth of loblolly pine seedlings on com 

pacted soils. Soil Science Society of America 

Proceedings; 1967; 31:565-568. 

Hatchell, G. E. Soil compaction and loosening 

treatments affect loblolly pine growth in pots. 

USDA Forest Service Research Paper SE-72; 1970; 

9 PP* 

Hatchell, G. E.; C. W. Ralston; and R. R. Foil. 

Soil disturbances in logging: Effects on soil 

characteristics and growth of loblolly pine in 

the Atlantic coastal plain. Journal of 

Forestry; 1970. 68:772-775. 

Hatchell, G. E. Site preparation and fertilizer 

increase pine growth on soils compacted in 

logging. Southern Journal of Applied Forestry; 

1981; 5:79-83. 
Management of Established Stands 

Moderators: 

James B. Baker 

Southern Forest Experiment Station 

Robert G. Blackmon 

University of Arkansas 

PREGOMMERCIAL THINNING OF PINE REGENERATIOM IN UNEVEN-AGED STANDS^/ 

Michael D. Cain, James 8. Baker, and Paul A. Murphyz/ 

Abstract.--PrecommerGial thinning is a proven management technique for increasing growth of loblolly (pinus 

taeda L.) and shortleaf (E. echinata Mill.) pine regeneration in overstocked, even-aged stands, but no information 

has been available for uneven-aged management. This study 

compared growth of submerchantable pines over a 5-year 

period on unthinned plots (averaging 2,000 stems per acre) 

with growth on plots precommercially thinned to 800, 500, 

and 200 stems per acre. Hardwoods were controlled in all 

treatments. Annual growth gains were achieved by precommercial thinning but only at the lowest density level, 

Five-year radial growth of overstory pines was not improved 

by precommercial thinning of the understory pine component. 

INTRODUCTION 

In uneven-aged stands of loblolly (pinus 

taeda L.) and shortleaf (g. echinata ~ill.)pine, 

natural seeding can result in dense patches of 

even-aged pine reproduction that exceed 1,000 

stems per acre. Such intraspecific competition 

may restrict optimum growth and development of 

individual stems and thereby delay harvests, 

Past research in overstocked, even-aged 

stands of loblolly pine has shown that substantial volume gains can be achieved when density is 

reduced to 500 to 750 pine stems per acre by 

precommercial thinning (Mann and Lohrey 1974). 

However, there has been no research to determine 

if natural regeneration in overstocked unevenaged stands would respond to various levels of 

precommercial thinning. This study was conducted 

to determine if precommercial thinning of highdensity, natural pine regeneration is a viable 

alternative to no thinning in uneven-aged 

loblolly-shortleaf pine stands. 

L/ Paper presented at the Southern Silvicultural 

Research Conference, Atlanta, GA, November 4-6, 

1986. 

z/ Authors are, respectively, Silviculturist, 

Crossett Experimental Forest, Crossett, AR; 

Principal Silviculturist, and Principal 

Mensurationist, Forestry Sciences Laboratory, 

Monticello, AR, Southern Forest Experiment 

Station, USDA Forest Service, in cooperation with 

the Department of Forest Resources and Arkansas 

Agricultural Experiment Station, University of 

Arkansas at Monticello. 

METHODS 

Study Area 

The study was located on the Crossett 

Experimental Forest in Ashley County, Arkansas. 

Soils on the study plots are principally Bude 

(~lossa~uic ~ragiudalfs) and Providence (~ypic 

~ragiudalfs) silt loam (USDA 1979). Both soils 

are loessial deposits with an impervious layer at 

18 to 40 inches that impedes internal drainage. 

Both have high potential productivity for 

loblolly pine with a site index of 85 to 90 feet, 

base age 50. 

Study plots were located throughout the 

1,680-acre experimental forest in dense patches 

of advanced pine reproduction (stems less than 

3.6 inches d.b.h.). The stands in which the 

plots were located contained a mixture of 

loblolly and shortleaf pines and had been managed 

under the selection system since the 1930's 

(~eynolds and others 1984). 

Study Installation 

In the summer of 1980, 36 circular 0.05-acre 

plots were established. Prethinning densities 

for seedling, I-inch, 2-inch, and +inch size 

classes averaged 539, 975, 443, and 190 pines per 

acre, respectively, on 0.02-acre measurement 

subplots across all treatments. All plots contained some overstory pines larger than 3.5 

inches d.b.h. Plots were stratified according to 

initial percent pine stocking (~c~emore 1981 ), 

then nine replications of four thinning treatments for pine regeneration were assigned at 

random. 
Treatments 

The four treatments included: (1) mthinned 

conlrcl, (2) thin Lo 800 stems per acre, (3) thin 

to 500 stems per acre, and (4) thin to 200 stems 

per acre, Treatments were based on recommended 

postthinning densities for rapid diameter growth 

in even-aged loblolly pine stands (Mann and 

Eohrey 1974). Well-f ormed dominants and ccdominants were left to provide uniform spacing, 

mminants and codominants were understory pines 

less than 3-6 inches d,b,h, whose crowns were in 

the uppermost layer of the regeneration canopy. 

Hardwoods were stem injected with herbicide 

in the summer of 1980, prior to thinning, Pines 

were bnd-thinned in October 1980 by a two-man 

crew using a chain saw and machette. Thinning 

time was generally dependent on initial density 

and size of pines being thinned and ranged from 4 

to 7 minutes per 0.05-acre plot. Hardwood 

regrowth and vines were controlled annually in 

mid-summer for 3 years after thinning. 

Measurements 

Residual pines on thinned plots and 800 

pretagged dominants and codominants per acre on 

control plots were measured in October 1980. 

Total height and height to live crown were taken 

to the nearest 0.1 foot and d.b.h. to the nearest 

CI,? inch. Ail surviving pines were remeasured 

mually through the fall of 1985. At the end of 

each growing season, all surviving pines on control plo"; were tallied by I-inch d.b,h. classes 

to monitor change in density as a result of 

natural mortality. In order to compute a pretreatment competition index (Daniels 1976) as a 

relative measure of point density on each plot, 

diameters of all merchantable-sized pines (those 

3.6 inches in d.b.h. and larger) that fell within 

a plot radius of a 10-factor prism were measured 

to the nearest 0.1 inch, and their distances from 

plod center were measured to the nearest 0.1 foot 

in October 1980. 

Five years after thinning, increment borings 

-were taken at breast height from overstory pines 

on or adjacent to study plots to determine the 

effect of thinning on their radial growth, 

Radial growth was measured to the nearest millimeter for two 5-year intervals: 1976 throl~gh 1980 

(pretreatment growth), and 1981 through 1985 

(posttreatment growth). Distance from each overstory pine to plot center was measured to the 

nearest 0.1 foot and used as an independent 

variable in covariance analysis, 

hnalysis of Data 

petition index was used as the concomitant 

variable in the covariance analyses of annual 

growth, One plot was deleted from analysis 

because sf logging damage unrelated to the study, 

and a second plot was deleted because of a 

heterogeneous competition index compared to other 

plots, Cubic-foot growth was calculated using 

stem taper equations developed for natural loblolly and shortleaf pine stands (Fasrar and 

Murphy 1985). Percent survival among treatments 

was compared using the arcsine transformation. 

Covariance analysis was also used to 

evaluate thinning effects on radial growth of 

overstory pines from 1981 through <985. Independent variables were radial growth in the previous 

5 years (1976 through 1980) and distance from 

subject tree to plot center. Differences among 

treatments in all covariance analyses were partitioned by Fisher's Protected LSD Test (~uitema 

1980). Analyses were carried out at the 0.05 

level of significance. 

RESULTS AND DISCUSSION 

Pine Regeneration 

These was an average of 1,988 submerchantable pines (3-5 inches d,b,h, and smaller) per 

acre on control plots in 1980, when the study 

began, Five years later this density had 

declined to 844 stems per acre, while 175 pines 

per acre had grown to merchantable size (table 

1). Approximately 5C percent of the pine regeneration present in 1980 survived five growing 

seasons where no thinning was done. 

Survival of the dominant and codominant 

measurement pines ranged from 81 percent on control plots to 97 percent on the 200 stems-peracre thinning regime. This indicated a significant increase in survival as density of pine 

regeneration was reduced by precommerciaf thinning (table 1). 

Only 15 to 17 percent of submerchantable 

pines on the control, 800, and 500 stems-per-acre 

treatments grew to merchantable size in 5 years. 

In contrast, 66 percent of submerchantable pines 

on the 200 stems-per-acre treatment grew to merchantability. Drastic thinning to 200 stems per 

acre had left only the largest understory pines-- 

they averaged almost 2 inch more in d.b.h, and 

about 5 feet taller than residual pines on zh.6 

other three treatments (table 2), Although control plots had more ingrowth to merchantable size 

when compared to the other treatments (table 'I), 

such ingrowth will vary depending upon the 3egree 

of overstory competition, initial diameters, and 

density of the regeneration. Therefore, ingrcwth 

trends are not necessarily indicative of longterm growth potential on control plots. 

Data from 34 of the original 36 plots were 

used in analysis of covariance to evaluate thinning effects on survival and on annual growth in 

d,b,h,, basal area, total height, and volume for 

the understozy pine component. Pretreatment com- 
Table 1,--Pine regeneration density and survival 5 years after thinning, with 

Survival 

1985 pine density of Pretreatment 

TMnning - (3.5" >3.6" Grew to 4" class measurement competition 

treatment d.b. h, dTb. h.?l after thinning pines index?/ 

--------- Sterns per acre---------- Percent 

Control 844 238 175 81 &/ 3.80 

200 ~tems/acre 67 21 1 128 97 C 4.87 

Includes overstory pines of sawlog and pulpwood size. 

- 21 Survival means followed by the same letter are not significantly different 

at the 0.05 level. 

Dj = d.b.h. of competitor (j); Di = 1 for plot center (i). 

nistij = Distance between plot center (i) and competitor (j). 

N = Number of competitors counted with 10 BA factor prism, 

s 

Table 2.--Mean size of pine regeneration in 1980 and 1985 

Thinning D.b.h. Total height Live-crown ratio 

trea tment 1980 I985 1980 1985 1980 1985 

---- Inches ---- -----Feet----- - ---Percent--- 

~ontroly 2.22 2.79 22.18 27.91 48 39 

800 ~tems/acre I .93 2.50 20.24 24.89 46 39 

500 ~tems/acre 2.12 2.64 21.34 25.11 47 40 

200 ~temslaere 2 93 3.96 26.97 33.61 51 46 

21 Measurements based on 800 dominant and codorninant stems per acre. 

Dominants and codominants on the 200 stemsper-acre treatment plots outperformed similar 

pines of the other three treatments in diameter, 

basal area, height, and volume growth per tree 

(table 3). The covariate, pretreatment competition index (table 11, had a statistically significant influence in the .analyses of pine regeneration growth. 

After adjustment for pretreatment competition index, statistical differences between 

treatments were generally significant only for 

200 stems per acre compared to any of the other 

treatments, With 500 stems per acre there was a 

significant diameter growth advantage over controls, There was no gain in growth by 

precommercial thinning to 800 stems per acre when 

compared to control plots where the only 

treatment was hardwood removal. 

Even though thinning submerchantable pines 

to 200 stems per acre in these uneven-aged stands 

resulted in significant growth gains over other 

treatments, an annual growth rate of only 0.2 

inch in diameter and 1.4 feet in height is about 

half what might be expected from comparable pines 

exposed to full sunlight (~ain 1985), as found in 

young even-aged stands, Since pine saw logs are 

worth more than small trees, most of the 

productive capacity of each acre in uneven-aged 

management is devoted to growing saw log-sized 

pines rather than maximizing growth of pine 
Table 3. - 

- Cubic feet 

Control 0.08& 0.24a 0,90a 0.04a 

-- 

I/ Adjusted for overstory pine competition index. 

Columnar means followed by the same letter are not significantly different 

at the 0.05 level. 

regeneration (~eynolds and others 1984). 

Reynolds (1959) published the diameter distribution for a well-stocked loblolly-shortleaf 

pine stand to be managed on a 5-year cutting 

cycle for the production of sawtimber, with 

pulpwood, poles, and pilings as secondary products. Reynolds suggested that the number of 

submerchantable stems (3.5 inches in d.b,h. and 

less) should total less than 100 per acre. Based 

on results in the present study, density of pine 

regeneration should be reduced to, at most, 200 

stems per acre to achieve growth gains, At least 

100 submerchantable pines per acre should be 

retained to insure replacement of overstory pines 

as they are harvested, 

Study plots in this study were established 

in well-stocked, mature pine stands that had been 

undisturbed for nearly 15 years prior to precommercial thinning. There were no major disturbances %o the overstory pine component during the 

5 years following thinning. However, with 

uneven-aged management, stand manipulation by 

scheduled cuts, hardwood competition control, and 

salvage of dead or dying trees occur at 

relatively short intervals of 5 to 10 years. 

These ongoing management practices tend to bring 

about random thinning of understory pine regeneration, As such, precommercial thinning may not 

be warranted in uneven-aged pine stands if these 

stands are being managed properly and have a wide 

range in size distribution for the submerchantable component, 

Whether there is a need for precornmercial 

thinning of pine regeneration in well-managed, 

uneven-aged stands of loblolly-shortleaf pine 

could not be answered by this study. However, 

there are rule-of-thumb recommendations regarding 

the need for precommercial thinning in even-aged 

stands. Chapman (1953) proposed that normal 

rates of diameter growth can be expected for 

loblolly pines in overstocked stands as long as 

the pines retain a 40-percent crown-height ratio. 

Likewise, Mann and Lohrey (1974) recommended that 

precommercial thinning in even-aged stands of 

less than 5,000 stems per acre be done only if 

live-crown ratios of dominants were expected to 

be less than 35 percent when the pines reached 

merchantable size. In the present study, the 

live-crown ratios for dominants and codominants 

averaged more Lian 45 percent in 1980 and more 

than 39 percent in 1985 (table 2). Since these 

crown ratios were within the range designated for 

normal growth, this may have been one factor 

contributing to the lack of significant growth 

response to thinning at all but the lowest 

density level. Owners of uneven-aged pine stands 

might use the live-crown ratio rule-of-thumb to 

determine the need for precommercial thinning of 

understory pines. 

Radial Growth of Overstory Pines 

Based on the results of this study, it was 

quite evident that overstory pines exerted a 

negative influence on the growth of pine regeneration during the 5-year interval. The recommended maximum basal area for merchantable-sized 

pines in uneven-aged stands is 75 square feet per 

acre so that natural pine reproduction,will 

become established and grow (~e~nolds and others 

19134). Y$t it was not uncommon for overstory 

pine basal area to exceed 100 square feet per 

acre on study plots, Less obvious was whether or 

not dense patches of pine regeneration had a 

negative impact on the radial growth of overstory 

pines . 

The number of overstory pines averaged from 

2 to 3 per 0.05-acre plot with mean diameters of 

18 to 21 inches d.b.h. (table 4). Distance of 

these pines from plot centers averaged about 21 

feet or just within the 0.05-acre radius of 26.3 

feet. 
Table 4.--Radial growth of overstory pines 

- Distance 

Thinning Pines to D.b.h. Radial growth w 

treatment L 

per plot plot center 1985 1976-80 1981-853 

Nusuber - Feet -----------Inches---------- 

Control 3 0 23.8 19.5 0.52 0.53 

1, Means adjusted for radial growth in previous 5 years and for distance 

from subject tree to plot center. 

Although analysis of covariance indicated 

that mean radial growth differences were Just at 

the level of statistical significance, a difference of only 0.08 inch over a 5-year period 

was thought to be unimportant. Also, radial 

growth did not increase with decreasing understory pine density. 

Therefore, in uneven-aged stands with mature 

loblolly and shortleaf pines averaging 20 inches 

in d.b.h. and up to 100 square feet of basal area 

per acre, radial growth of the overstory pines 

was not impaired by patches of up to 2,000 understory pines per acre in the absence of hardwood 

competition. Results might have been entirely 

different if measurements had been taken in 

stands where overstory pines had not reached 

maturity or where there were higher understory 

pine densities and dry years. 

SUNMARY AND CONCLUSIONS 

Past research has shown that volume growth 

of loblolly pine regeneration in even-aged stands 

will be maximized when the density is 500 to 800 

stems per acre. To improve growth in overstocked 

stands of pine regeneration, density can be reduced to recommended levels by precommercial 

thinning. Although optimum densities have been 

established for even-aged stands, there were no 

comparable density guide lines for uneven-aged 

stands of loblolly-shortleaf pines that have 

high-density regeneration. 

This study compared growth of submerchantable pines over a 5-year period on unthinned 

plots with growth on plots precommercially 

thinned to 800, 500, and 200 stems per acre. 

Hardwood competition was controlled on all plots. 

Annual growth gains were achieved by precommercia1 thinning but only at the lowest density 

level. Ongoing management practices at relatively short intervals of 5 to 10 years in wellmanaged, uneven-aged stands may result in random 

thinning of dense pine regeneration and negate 

the need for precommercial thinning. 

Hand thinning was used in this study to 

insure uniform spacing of we1 1-f ormed dominants 

or codominants. Such treatments may be practical 

on small woodlots, but large acreage would require more cost effective thinning methods such 

as mechanical treatment with rotary mowers or 

rolling-drum choppers. 

Five-year radial growth of the overstory 

pines was not improved as a result of precommercial thinning of the understory pine component. The overstory consisted mainly of mature 

pines that averaged 20 inches in d.b.h. Radial 

growth of such pines may be more strongly influenced by overstory pine basal area than by understory pine density. 

LITERATURE CITED 

Cain, Michael D. Prescribed winter burns can 

reduce the growth of nine-year-old loblolly 

pines. Res. Note SO-312. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1985, 4 p. 

Chapman, Herman H. Effects of thinning on yields 

of forest-grown longleaf and loblolly pines at 

Urania, La. Journal of Forestry. 51 : 16-26; 

1 953 

Daniels, Richard F. Simple competition indices 

and their correlation with annual loblolly pine 

tree growth, Forest Science. 22: 454-4563 1976. 

Farrar, Robert M.; Murphy, Paul A. Comprehensive 

tree volume functions for natural loblolly and 

shortleaf pines in Arkansas and north 

Louisiana. Monticello, AR: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Shtion; 1985; Final Office Report 

FS-SO-4106-4. 36 6 
Huitema, Bradley E. The analysis of covariance 

and alternatives. New York: John Wiley and 

Sons; 1980. 445 p. 

Mm, W.F., Jr.; Lohrey, R.E. Precommercial 

thinning of southern pines. Journal of 

Forestry. 72 : 557-560; 1974. 

McLemore, B.F. Hinimum stocking levels required 

for successful management of uneven-aged 

loblolly-shortleaf pine stands. In: 

Proceedings, 1st biennial southern silvicultural research conference; 1980 November 6-7; 

Atlanta, GA. Gen. Tech. Rep. SO-34. New 

Orleans, LA: U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1981 : 292-293. 

Reynolds, R.R. Eighteen years of selection 

timber management on the Crossett Experimental 

Forest. Tech. Bull. 4226. Washington, DC: U.S. 

Department of Agriculture; 1959. 68 p. 

Reynolds, R.R.; Baker, James B.; Ku, Timothy T. 

Four decades of selection management on the 

Crossett farm forestry forties. Ark, Agric. 

Exp. Sta. Bull, 872. Fayetteville, AR: 

University of Arkansas, Division of 

Agriculture, Agricultural Experiment Station; 

1984. 43 p. 

US. Department of Agriculture, Soil survey of 

Ashley County, Arkansas. Washington, DC: Soil 

Conservation Service and Forest Service in 

cooperation with Arkansas Agricultural 

Experiment Station; 1979. 92 p. 
SLASH PINE SHOWS MIXED RtSPOKSE TO POTASSIUK FERTILIZEKI' 

Eugene Shoulders and Ailan E. ~iark2' 

Abstract.--Potassium fertilizer was applied with and without nitrogen 

and phosphorus to two slash pine (Pinus eZZiottii Engelm, var eltiottii) 

plantations in Louisiana. One plantation, fertilized at the time of 

establishment showed no response to potassium through age 13. The other 

plantation, thinned to 80 square feet of basal area per acre and fertilized 

at age 25, grew faster in height, diameter, and volume during the ensuing 9 

years when potassium was included in the fertilizer mix. While differences 

in the age of the plantation when fertilizers were applied cannot be 

entirely ruled out as a reason for the difference in response, exchangeable 

soil potassium appears to be the most likely factor. The results suggest 

that slash pine should respond significantly to potassium fertilization if 

the surface soil (0- to 6-inch) layer contains less than about 20 pounds per 

acre (10 ppm) of exchangeable potassium. 

INTRODUCTION 

Potassium fertilization is not a widely 

accepted management practice for southern pine 

plantations on Gulf and Atlantic Coastal Plain 

soils. Levels of exchangeable potassium in many 

of these soils, however, suggest that inadequate 

amounts of available potassium may limit growth of 

pines, especially where nitrogen and/or phosphorus 

deficiencies have been eliminated. Field and 

greenhouse studies have shown that even though 

soil potassium levels are low by agronomic 

standards, pines may or may not respond to 

potassium fertilization (McKee 1978; Pritchett 

1979a, 1979b; Pritchett and Smith 1972; Pritchett 

and Comerford 1483). Results are reported in this 

paper of two field fertilizer trials in 

Louisiana--one where potassium increased growth of 

slash pine (Pinus elliottii Engelm. var elliottii) 

and one where it did not--and discusses possible 

reasons for the difference in response difference 

response. 

FERTILIZER APPLIED AT TIME OF ESTABLPSHMEhT 

Methods 

In one study, a direct seeded slash pine stand 

was fertilized at time of sowing. Potassium 

levels of O and 62 lbiacre were tested on plots 

that were fertilized with 34 lbs/aere of nitrogen 

and 44 lb/acre of phosphorus (fig 1), An 

unfertilized control was also included, 

Phosphorus was supplied either as polyphosphate in 

a liquid formulation supplied by Allied Chemical 

Corp. or as granular triple superphosphate, Since 

chemical formulation had no effect on response of 

pines to phosphorus, only an average for the two 

sources are reported. The polyphosphate Liquid 

also served as the carrier for nitrogen and 

potassium. 

Treatments were replicated three times in a 

randomized block design. Blocking was by soil 

series: two blocks on Beauregard soil (Plinthaquic 

kaleudult, fine-silty, siliceous, thermic) and one 

on Kuston soil (Typic Paleudult, fine-loamy, 

siliceous, thermic), hacro nutrient status and 

~ther selected properties of the unfertilized soil 

are listed in table 1, 

Slash pine was row seeded on beds in hovember 

1969. Fertilization, bedding, and seeding were 

accomplished with equipment designed to 

incorporate the fertilizers into the beds. Prior 

to this operation a11 residual trees and logging 

debris from the previous crop had been removed 

from the site and the area had been disked, 

Beds were spaced 10 feet apart, Afrer I year, 

trees were thinned and shovel transplanted using 

shovels as needed to produce an in-row spacing of 

approximately 6 feet. Measurement plots contained 

4 rows of 25 trees each and were 0.1L acre in 

size. 

L/ Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, 

November 4-6, 1986 

- 2/ Principal Silviculturist and Soil Scientist, 

respectively, Southern Forest Experiment 

Station, USDA-Forest Service, Pineville, LA. 

Tree heights were measured after 1, 2, 3, 5, 5, 

9, and 13 years. Diameters were included in the 

last three inventories. Total inside bark volumes 

at 6, 9, and 13 years were computed from Schmitt 

and Bowerrs (1970) u2ki equation for young slash 

pine. Growth differences between treatments were 

tested by analyses of variance using a probability 

level or 0.05. 
Table 1.--Selected properties of unfertilized soils 

from the two studies 

Soi 1 Unit of 

Property Measure 0 Years 25 Years 

PH unit 5.2 4.8 

0 .H, percent 2.2 2.1 

P PPm 3.6 1.6 

Ca PPm 245 128 

f?g PPm 43 2 1 

K PPm 2 7 8 

Results 

Individual degree-of-freedom comparisons showed 

that all nitrogen plus phosphorus fertilizations 

significantly increased average tree height at all 

ages, but that the additions of potassium had no 

significant additional effect on height (fig. 1). 

Although there was a consistent pattern for trees 

on potassium fertilized plots to be shorter at all 

ages than those receiving only nitrogen and 

phosphorus, the trend was not signiticant. 

AGE (YEARS) 

Figure 1. Effect of fertilization at tine of 

sowing on height growth of direct-seeded slash 

pine. 

Trees on nitrogen plus phosphorus treated plots 

were also significantly larger in quadratic mean 

diameter at 6, 9, and 13 than trees on control 

plots (fig. 2). As with heights, the addition of 

potassium had no significant effect on quadratic 

mean diameter. 

The trends in total cubic volume per acre were 

similar to those for height and diameter, but only 

the difference at age 6 between fertilized and 

control treatments was significant (fig, 3). 

Greater mortality after age 6 on fertilized than 

on unfertilized plots may account for the apparent 

lack of response to fertilizer at the older ages. 

However, differential mortality cannot explain the 

lack of response to potassium; there were no 

significant differences in stocking at 9 and 13 

years between fertilized plots that received 

potassium and those that did not. 

FERTILIZER APPLIED (lb/acre) 

34 N, 44 P, 62 K 

0 

6 9 12 15 

AGE (YEARS) 

Figure 2. Effect ot fertilization at time of 

sowing on diameter growth of direct-seeded slash 

pine. 

1500 I I ' 1'. 

C\ 

0) FERTILIZER APPLIED (lb/acre) 

6 . 1. 1. I 

9 12 15 

AGE (YEARS) 

Figure 3. Effect of fertilization at time of 

sowing on total volume (i.b.) of direct-seeded pine 

at 6, 9, and 12 years. 

FERTILIZATION FOLLOKIhG THIhNING 

rle thods 

The second study was established in a 

25-year-old slash pine plantation. The stand had 

received a sanitation thinning at age 18 and was 

thinned again to 80 ft2/acre of basal area 

immediately before fertilizers were applied. 

Actually, two experiments were established in this 

plantation: One in which plots having a gross 

area of 0.50 acre were fertilized by broadcasting 

the tertilizer over the surface of the entire plot, 

and one in which individual dominant and 

codominant trees were fertilized by distributing 

the material evenly over a circular area 33 feet 

in radius around individual stems. The soil was 

Caddo silt loam (Typic Glossaqualf, fine-silty, 

siliceous, thermic). 

In the plot experiment, levels of 0 and 50 

lblacre of potassium were tested on plots 
fertilized with 100 lblacre of nitrogen and 22 

lb/acre of phosphorus, A wider array of nitrogen 

plus phosphorus combinations was tested with and 

without 50 lblacre of potassium in the experiment 

with individual dominant and codominant trees: no 

nitrogen and no phosphorus, no nitrogen and 22 

lblacre of phosphorus; 10Q lb/acre of nitrogen 

with 22 lblacre of phosphorus; 200 lbfacre of 

nitrogen with 22 lblacre of phosphorus. Carrier 

for the nutrients were urea, triple 

superphosphate, and muriate of potash, 

Treatments were replicated three times in the 

plot experiment and nine times in the individual 

tree experiment. The tests were established in 

March 1973 and reinventoried after 3, 6, and 9 

years. Tree volumes were calculated by the 

height-accumulation procedure (Grosenbaugh 1954) 

and 3-, 6-, and 9-year perlodic growth rates in 

diameter, height, and cubic volume were computed. 

Growth differences between treatments were tested 

by analyses of variance using the 0.05 level of 

probability. 

Results 

In the plot experiment, potassium significantly 

stimulated average height growth of the stand 

during the second 3-year period, and this 

difference persisted after 9 years. Actual 

average height growth for 3, 6, and 9 years was as 

follows : 

Elapsed 

time in 

Years 

Periodic height growth (feet) 

No K 50 Ibla K 

A similar trend in volume growth was not 

significant, and average diameter growth on plots 

was unaffected by potassium fertilization. The 

results might have shown significance had there 

been more replicates. 

Potassium fertilization increased 9-year mean 

diameter growth of individual dominant and 

codominant trees by 0.27 inch (table 2), 

boosted 9-year average height growth by 2.3 feet 

and increased cubic volume growth per tree by 1.6 

ftJ. Differences in diameter and height growth 

were significant and were accompanied by an 

11-percent increase in cubic-volume growth. The 

latter difference had only an ll percent 

probability of occurring due to chance. Our 

inability to precisely determine the total volume 

in 25- and 34-year old trees without destroying 

them undoubtedly contributed to the lack of 

significance. 

Why did potassium fertilization stimulate 

growth of one plantation and not the other? 

Certainly, levels or exchangeable potassium in the 

unfertilized soil was a major contributing factor. 

Soil of the older and responsive plantation 

contained only 8 ppm of exchangeable potassium, 

whereas soil of the younger and unresponsive 

plantation contained 27 ppm--19 ppm more. 

Differences of this magnitude can be important. 

In a greenhouse study with Caddo soil (in pots) 

from two locations in central Louisiana, slash 

pine seedlings growing in unamended soil 

containing 35 ppm of exchangeable potassium 

produced 128 percent more dry weight in one year 

than those on soil containing 23 ppm (McKee 1978). 

Another important result in McKeels (1978) study 

was that the addition of 62 ppm of potassium to 

the less productive soil more than doubled 

seedling dry weight, whereas the same amount 

increased seedling dry weight on the more 

productive soil by less than 20 percent. Since 

pot studies place greater stress on soil nutrients 

than field experiments, these results are 

inappropriate for establishing critical levels of 

potassium in soil. Under field conditions, 

Pritchett and Comerford (1983) concluded that 

slash pine should respond to potassium 

fertilization if the soil contains less than 8 to 

12 ppm of double-acid extractable potassium and 

other factors are not limiting. Our results 

support their conclusion. 

Other factors that could have contributed to the 

lack of response to potassium in the younger 

plantations are deficiencies of other nutrients 

and competition from herbaceous plants. 

Differences in rates of fertilization had no 

apparent effect on growth response since the 

responsive plantation was fertilized with 50 

lb/acre of potassium, while the unresponsive 

plantation received 62 lb/acre. 

Table 2.--Effect of potassium fertilization at age 25 on 9-year height, 

diameter, and volume growth of individual dominant and codominant slash 

pine trees 

K added 

Growth Unit (lbf acre) Iliff- ProbPleasured erence ability 

Diameter growth Inches 2.1 2.5 0.4 0.002 

Height growth Feet 12.6 4.8 2 .3 ,008 

Volume growth Cubic feet 15.4 17 .O 1.6 .108 
Application of nitrogen and phosphorus would 

have corrected any initial deficiencies of these 

nutrients in unfertilized soil that might affect 

response to potassium, txchangeable calcium and 

magnesium levels appeared adequate for pines at 

both locations and kere actually higher in soils 

of the unresponsive plantation than soils of the 

responsive one. Soil pH and organic matter were 

favorable tor pine growth at both locations. In 

short, there were no obvious soil conditions that 

should limit the younger plantation's response to 

potassium, 

When ake or stage of development or the 

plantation at rertilization is considered, one 

would not expect germinating seeds and young 

seedlings to compete as vigorously with other 

vegetation for added nutrients as plantations that 

have overtopped this competition. The slower 

growth of the first study on direct seeded pines 

where potassium was added to the nitrogen and 

phosphorus suggests that potassium may indeed have 

stimulated growth of competing vegetation to the 

detriment of the pines. But the positive response 

of the plantation to nitrogen and phosphorus 

fertilizer indicates that the pines were able to 

compete. To say that the age or stage of 

development was a factor in the differential 

response is questionable since the response of 

herbaceous vegetation to fertilization was not 

measured. 

Our results do imply that potassium 

fertilization should increase growth of slash pine 

plantations if other nutrient deficiencies have 

been eliminated and if the soil contains less that 

about 10 ppm, or 20 lb/acre, of exchangeable 

potassium in the 0- to 6-inch layer 0% surface 

soil. 

The research reported here was greatly 

facilitated by labor, equipment, materials, and/or 

land furnished for the experiments by Allied 

Chemical Co., T. L. James and Co,, Lnc.; Owens 

Illinois, Inc.; and the Louisiana Department of 

Agriculture and Forestry. 

LITEMTUKE CITED 

Grosenbaugh, L. K., hew tree-measurement concepts: 

height accumulation, giant tree taper, and 

shape. South. For. Lxp. Stn., kew Orleans, LA, 

b.3. Dept. Agric. For, Serv. Occas, Pap, 134, 

1954. 32 p, 

LcKee, W. h., Jr. Slash pine seedling response to 

potassium and calcium on icipertectly drained 

coastal pla~n soil. Plant and Soil, 50: 615-624; 

1978. 

Pritchett, h. L. Properties and Management ok 

forest soils. hew York, John WiLey and Sons, 

Inc.; 1979a. 500 pp. 

Pritchett, W. L. Site preparation and 

fertilization of slash pine on a wet savanna 

soil. Southern Journai of Applied Forestry. 3: 

87-90. 1979b. 

Pritchett, U. L. and Comerford, 14. B. tvutrition 

and fertilization of slash pine. In: Stone, E, 

L., ed. The Managed Slash Pine Ecosystem; 1981 

June 9-11; Gainesville, FL. School of Forest 

Resources and Conservation, University of 

Florida Press. 1983; 49-90. 

Pritchett, W. L. and Smith, k. H. Fertilizer 

responses in young pine plantations. Soil 

Science Society ot America Proceedings, 30: 

660-663. 1472. 

Schmitt, Dan, and bower, Dave. Volume tables for 

young loblolly, slash, and longleaf pines in 

plantations in south kiississippi. ges, iiote 

SO-10.2, hew Orleans, LA: UeS. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1970, kyp, 
EFFECT OF LEGTiMES ON PINE GROWTH IN THINNED 

i l LOBLOLLU PIHE PWTATIOKS - 

2 1 Terry It. Clason - 

Abstract.--Nitrogen fertilizer can stimulate residual pine 

growth in recently thinned pine plantations. Since leguminous 

plants may offer a cost effective alternative to nitrogen 

fertilizer, a study evaluating legume establishment methods and 

influence on residual pine growth was initiated in a 25-year-old 

loblolly pine plantation. Lespedeza cuneata and Trifolium 

subterraneum seed were broadcast in a loblolly pine plantation 

recently thinned to 100 TPA. Establishment methods included 

unburned and burned seedbeds that were either unfertilized or 

fertilized with 30 and 60 lbslacre of phosphorus and pot~ssium, 

First year lespedeza and clover stocking was bt>tter on the 

burned, fertilized seedbeds. After 5 years, lespedeza averaged 

2,500 lbs of dry matterfacre on the burned, fertilized seedbed; 

clover was not present on any treatmect. Pim growth and soil 

nutrient content was not influenced by lespedeza. 

Keywords: sericea lespedeza, subterranean clover 

INTRODUCTION 

Thinning and nitrogen fertilization can have 

a remedial effect on productivity of oversto-ked 

loblolly pine plantations. Ballard et al. "1980) 

reported 4 year net growth of thinned plantations 

exceeded unthinned plantations by 70 feet /acre 

after both were fertilized with 150 lbs of 

nitrogen/acre. Thinning reduces intra-specific 

competition by removing smaller pines and 

providing additional growing space for remarning 

pines. Nitrogen fertilizer stimulates residual 

pine crown growth which improves reoccupancy of 

additional growing space. 

Nitrogen fertilizer growth enhancement in 

thinned stands could be obtained with leguminous 

plants. Jorgensen (1980) suggested that minimum 

acceptable annual nitrogen accretion rate for 

legumes in forests was 50 to 100 lbsfacre. If 

biologically derived nitrogen is available for 

pine use, then nitrogen availability over a 4-year 

period would be equivalent to the amount of 

fertilizer nitrogen applied by Ballard et al. 

(19801, In addition, a dense stand of leguminous 

plants could influence long-term site productivity 

by improving soil physical and nutritional 

characteristics, 

A study was initiated at the Hill Farm 

Research Station, 3omer, LA in a previously 

overstocked loblolly pine plantation to evaluate 

the combined effect of thinning and biologically 

derived nitrogen - or residual pine growth. Sericea 

lespedeza (Lespedeza cuneata: and Mt. Barker 

subterranean clover (Trifolium subterraneum) were 

the legumes chosen for the study. Selection was 

based in criteria developed by jorgensen (1980). 

The objectives of the study were to determine: 

1, Efficient methods for lespedeza and 

sub-clover establishment; 

2. Effect of Lespedeza and sub-clover on soil 

nutrient levels; and 

3. Short- and long-term effects of lespedeza 

and sub-clover on residual pine growth. 

METHODS A39 PROCEDURES 

'/Paper presented at the Fourth Biennial 

Southern Silvicultural Research Conference, 

Atlanta, Georgia, November 4-6, 1986. Approve$ 

for publication by the Director of the Louisiana 

Agricultural Experiment Station as manuscript 

number 86-80-0368. 

2/~ssociate Professor, Hill Farm Research 

Station, LSU Agricultural Center, Homer, LA 

71040. 

The research area was a 4-acre, 25-year-old 

loblolly plne plantation growing on a Ruston fine 

sandy loam soil with an average site .index of 63 

at age 25, Plantation stocking Level at age 20 

was reduced From 850 to 406 trees per acre (TPA). 

The experimental -esign was a siandomized 

complete block with split plots. ?.fain plot 

treatments were burned and unburned seedbed 

preparatiofi. There were six split plot 

treatments, which included: 1) sub-clover with 

fertilizer (cI;v/F); 2) lespedeza with fertilizer 
(LES~F); 3) sub-clover (CLV); 4) lespedeza (LES); 

5) sub-clover and lespedeza (cLV-LES); and 6) 

control (CON). The plantation was divided into 

three 1.3 acre blocks with burned and unburned 

seedbeds replicated randomly in each block on a 

0.6-acre plot, Split plot treatments were 

assigned randomly to 0.1-acre plots in each main 

plot. 

In December 1981, the plantation was thinned 

to 100 TPA and seedbed preparation treatments 

applied to the appropriate plots. Immediately 

following seedbed preparation, phosphorus (P) and 

potassium (K) were applied at 30 and 60 lbslacre, 

respectively, to the appropriate split plot 

treatments. Legumes were hand seeded at 10 

lbslacre with sub-clover being inoculated and 

applied in February, 1982 and-lespedeza in March, 

1982. 

Soil samples were taken to a depth of 1 foot 

prior to, and 5 years after, legume establishment. 

Legume treatment stocking rates were estimated in 

May, 1982 and June, 1986 by averaging the number 

of plants found on 5-milacre plots within each 

0.1-acre plot. Also, treatment dry matter 

production was determined for 1986. Individual 

tree data were collected in December, 1981 and 

June, 1986. Measurements included DBH, bark 

thickness, total height, height to base of live 

crown, and crown radius. A11 data were analyzed 

by ANOVA procedures, and individual mean differences were contrasted orthogonally. 

RESULTS AND DISCUSSION 

Tree growth data were collected in June, 1986 

because a hail storm in April damaged the 

plantation so severely that tree mortality 

occurred in June. Although growth data were 

analyzed and presented as the 5-year increment, 

the actual growth period was less than 5 years. 

In addition, hail damage prevented estimation of 

tree crown growth and development. 

Legume Establishment 

Legume stocking was influenced by seedbed 

preparation and species (Table 1). Initial 

stocking levels (1982) were greater on burned 

plots. Sub-clover stocking averaged 20 

plants/milacre on burned plots and 2 

plantslmilacre on unburaed plots. No clover 

stocking differences were attributed to P and K 

fertilizer on either burned or unburned plots. 

Lespedeza stocking was greater than clover, 

averaging 76 and 45 plantslmilacre on burned and 

unburned plots, respectively. The greatest 

initial stocking, 177 plantslmilacre, was achieved 

with lespedeza on burned plots fertilized with P 

and K. 

The more persistent legume understory was 

produced with lespedeza. Legume stocking levels 

in 1986 revealed that no sub-clover understory was 

present, and the lespedeza understory averaged 75 

plantslmilacre (Table 1). Lespedeza stocking on 

the fertilized treatments averaged 180 

plantslmilacre and was significantly greater than 

unfertilized treatments. Mean lespedeza stocking 

on burned fertilized plots was 242 plantslmilacre, 

which exceeded stocking of the lespedeza 

fertilized unburned plots by 123 plantslmilacre, 

Significantly higher stocking rate on the 

burned LEs/F treatment resulted in an understory 

that was two to six times larger than other 

treatments. This was shown by the 1986 dry matter 

production yields: 

Yields 

Treatments Burned Unburned ------- lbslacre-------- 

CLV/F 398 933 

LES / F 2,537 1,262 

CLV 927 855 

LES 662 668 

CLV-LES 7 36 897 

CON 618 86 1 

Improving lespedeza stocking at time of establishment with burning and fertilization enhanced 

development of a lespedeza understory. Jorgensen 

(1982) reported similar results for lespedeza 

following seedbed preparation and fertilization. 

Table 1. Legume stocking levels, 1982 and 1986 

Treatment Clover Lespedeza Clover Lespedeza --------- plants/milacre---------- 

CLV/F 19 

LES/F --- CLV 25 

LES --- 

CLV-LES 11 

CON --- 

CLVI F 3 

LES /F --- CLV 1 

LES --- CLV-LES I 

CON --- 

Burned --- --- --- 

177 --- 242 --- --- --- 3 7 --- 16 

15 --- 5 --- --- --- 

Unburned --- --- --- 

3 5 - -- 119 --- -- - --- 3 0 --- 24 

7 1 --- 48 --- --- --- 

Soil Nutrient Levels 

Table 2 provides soil analysis data for 

organic matter, and P and K levels prior to legume 

treatment establishment. Initial soil nutrient 

levels did not vary among treatments. Mean values 

for all treatments were organic matter, 0.47 

percent; P, 5 ppm; and K, 21 ppm. Organic matter 

levels, 5 years after establishment, did not vary 

among treatments and averaged 1.11 percent (Table 

3). Soil concentrations of P and K were not 

influenced by burning or legume species. P 

averaged 6.0 and 7.3 ppm for the burned and 

unburned treatments, respectively, 
while R averaged 31.6 and 22,6 ppm for burned and 

unburned. Soil concentrations of P and R for all 

fertilizer treatments averaged 9.2 and 35.8 ppm 

and were larger than the unfertilized treatments, 

which averaged 5.3 and 22.4 pprn for P and R, 

respectively. 

There was no apparent relationship between 

net nutrient concentration changes during the 

5-year growth period and understory density. The 

largest organic matter increase, 0.89 percent, 

occurred on the burned CLV/F treatment, which had 

no legume understory and the lowest dry matter 

production of 398 lbslacre. Burned LES/F 

treatment had the most dense legume understory and 

the highest dry matter yield, 2,537 lbslacre, but 

organic matter only increased 0.59 percent. 

Although inorganic nutrient changes were as erratic as organic matter changes, 1986 soil 

analysis indicated that the dense understory in 

the LES/F treatments did not deplete inorganic 

nutrient levels. 

Table 2. Soil nutrient levels, 1981 

Treatment Organic Matter P K 

percent PPm----- 

Burned 

CLV/F 0.39 5 2 7 

LES/F 0.53 5 16 

CLV 0.55 5 17 

LES 0.53 5 18 

CLV-LES 0.33 5 2 0 

CON 0.48 5 2 1 

Unburned 

CLV/ F 0.61 5 17 

LES/F 0-53 6 2 7 

CLV 0.48 5 2 2 

LES 0.35 6 19 

CLV-LES 0 .50 5 2 4 

CON 0.42 5 2 2 

Table 3. Soil nutrient levels, 1986 

Treatment Organic Matter P K 

percent ---- ppm---- 

Burned 

CLV/F 1.25 7 27 

LES/F 1.12 6 54 

CLV 1.09 6 32 

LES 0.99 5 23 

CLV-LES 0.97 5 36 

CON 1.07 7 18 

Unburned 

CLV/ F 1-22 12 31 

LES/F 1.28 12 31 

CLV 0.99 6 24 

LES 1.08 5 16 

CLV-LES 1.21 5 19 

CON 1.00 5 15 

Individual Tree Growth 

Significant tree growth differences were 

detected among treatments (Table 4). There were 

no growth differences between main plot 

treatments, Burned treatment DBH, height, and 

merchantable volume growth averaged 1.5 inches, 

2.5 feet, and 4.4 feet3, respectively, and 

unburned averaged 1.7 inches, 2.2 feet, and 5.0 

feet3. Control treatment tree growth was 

significantly less than all of the legume 

understory treatments. The largest tree DBH and 

volume growth occurred on the unburned CLV/F 

treatment, averaging 1.9 inches and 6.1 feet3. 

The dense understory on the LES/F treatment did 

not increase or decrease tree growth. Average 

DBH, height, and volume for trees on the LES/F 

treatment was 1.6 inches, 2.4 feet, and 4.8 feet3, 

while mean DBH, height, and volume for all 

treatments was 1.6 inches, 2.4 feet, and 4.7 

feet3. 

Table 4. Mean tree growth between 1981 and 1986 

Merchantable 

Treatment DBH Height Volume 

inches feet feet5 

CLV/ F 

LES/F 

CLV 

LES 

CLV-LES 

CON 

CLV/ F 

LES / F 

CLV 

LES 

CLV-LES 

CON 

Burned 

2.4 

1.6 

3.2 

3.8 

2.8 

1.4 

Unburned 

1.4 

3.0 

2.5 

3.1 

1.4 

1.9 

Tree growth data indicated that there was no 

growth response to a leguminous understory growing 

under widely spaced pines. Reducing pine stocking 

to 100 TPA may have masked any residual pine 

growth response that could have been attributed to 

leguminous plants. Site quality of the treatment 

plots varied greatly as indicated by treatment 

site indices: 

Site Index Age 25 

Treatments Burned Unburned 

--.-------feet---------- 

CLV/F 6 2 66 

LES/F 65 6 3 

CLV 6 5 6 3 

LES 6 2 65 

CLV/LES 63 64 

CON 64 6 1 

Comparing site index with tree DBW and volume 

growth showed that the higher the site index, the 

greater the tree growth. This occurred regardless 

of the legume treatment. Since the experimental 
design of the study did not block treatments on 

site quality, the probability of detecting 

significant growth responses among treatments was severely diminished. 

CONCLUSIONS 

Sericea lespedeza has greater potential as a 

biological source of nitrogen for pine growth than 

sub-clover. Legume stocking results showed that 

lespedeza was easy to establish, persisted without 

additional maintenance, and produced a dense 

leguminous understory. Recommended lespedeza 

establishment procedures, which are similar to 

those reported by Jorgensen (1982), include 

seedbed preparation by burning and fertilizing, 

and seeding inoculated seed at 10 lbs/acre in late 

winter. 

The heavy lespedeza understory that developed on the burned and fertilized seedbeds did not 

decrease soil nutrient levels or reduce tree 

growth. These short-term results would not 

justify the cost of establishing a lespedeza 

understory as a biological nitrogen source in 

thinned pine plantations growing on Ruston fine 

sandy loam soils. 

LITERATtPRE CITED 

Ballard, R., W. W. Ltuzan, and M. B. Kane. 1980. 

Thinning and fertilization of loblolly pine 

plantations. p. 100-104. & 3. P. Barnett 

(Ed) Proceedings of the 1st Biennial Southern 

Silvicultural Research Conference. Atlanta, 

GA . 

Jorgensen, J. R. 1980. Use of legumes in 

southern forestry research. p. 205-211. In J. 

P. Barnett (Ed) Proceedings of the 1st ~ie;;flial 

Southern Silvicultural Research Conference. 

Atlanta, GA. 

Jorgensen, J. R., and C. E. Davis. 1980. Methods 

of sericea lespedeza establishment for forest 

soil improvement. p. 48-53. In E. P. Jones, 

Jr. (Ed) Proceedings of the 2nd Biennial 

Southern Silvicultural Research Conference. 

Atlanta, GA. 
EARLY RESULTS OF SILVICULTURAL AND ECOLOGICAL IMPACTS OF 

Timothy R. Bottenfield, Michael S. Golden, Ralph S. Meldahl, 

Jon P, Caulf ield, Bobby L. Lanford, and Donna N. err^^ 

Abstract.--A study was initiated in 1985 to document 

and compare silvicultural and ecological impacts of representative mechsnized first-thinning systems in loblolly pine 

(Pinus tseda L.) plantations on the Upper Coastal Plain 

of the Southesst. Plots estsblished in two stands were 

measured before and after thinning with a selective forwsrder 

system. Stand ages were 15 2nd 17 years, and site indices 

were 85 feet at age 25 for both stands. Stems per acre 

at thinning were 669 and 468, snd the residual stand densities after thinning were 262 and 173, respectively. High 

impact strata (areas defined by placement of vehicle corridors, whole tree bunches, log piles, and skid trails) 

encompassed 37 and 25 percent of the stands areas. Of 

the residuals, 54 and 32 trees per acre had observable 

damage from logging equipment. Scar area per damaged tree 

averaged 34.6 and 18.4 square inches in the two stands. 

A significant increase in soil bulk density occurred only 

in the corridors. Recently, plots were established in 

a 15-year-old stand (site index 85 at age 25) where selective 

forwarder and fifth-row skidder systems operated side by 

side. Measurements were obtained before and after thinning. 

Continued measurements on soils, growth, and mortality 

will be taken on these and other sites where selective 

forwarder and fifth-row skidder systems are operational. 

INTRODUCTION 

Inventory data indicate that several million 

lcres of pine plantations in the Southeast 

will have reached commercially thinnable size 

during the 198(Sfs, with an annual potential 

of about 1,000,000 acres by the end of the 

decade (Knight and Sheffield 1980, Stokes 

and Lanf ord 1332) . The majority of these 

plantations are loblolly pine (Pinus taeda 

L.) 2nd about half are on forest industry 

lands (Knighc and Sheff ield 1980). 

Thinning is a controversial topic among 

forest land managers in the South. The controversy begins with the question of whether 

to thin and continues with how and when to 

thin. However, it is generally accepted thst 

the potential benefits from thinnings in ~211- 

to densely stocked southern pine stands include: 

bper presented at Southern Silvicul tura l 

Rssearc h Conference, Atlanta, Georgia, November 

4-69 1586. 

2~esc 3rch Assoc; lte, Associate Professor, 

Assistant Professor, Assistant Professor, 

Associ?te Professor, and Forestry Research 

Specialist, respect,ively, School of Forestry 

and Alabama Agricultural Experiment Station, 

Auburn University, Auburn, Alabama 36849. 

1. Greater control of the growing stock 

carried to the end of rotation (Walker 

1982, Feduccia 1983). 

2. Increased diameter growth. 

3. Volume growth concentrated on fewer 

trees, yielding larger, more valuable 

trees at rotation age. 

4. More cost effective late-rotation 

and final harvest in thinned stands 

than in unthinned stands. 

5. Allows utilization of trees otherwise 

lost through natural mortality. 

6. Keeps mortality losses of merchantable 

trees at a minimum by removing diseased, 

damaged, and suppressed trees. 

7. Higher total merchantable volumes 

(including that removed in thinning) 

in moderately thinned plots csrried 

to 30 to 35-year rotations than in 

unthinned check plots (Mann and Feduccia 

1976, Blackwelder 1982, Clason 1982). 

8. Reduced financial risk. 

The application of thinning in pine plantations 

ranges between two extremes - completely selective and strictly row. Completely selective 

thinning removes trees based on silvicultural 

criteria such 3s quality, tree spacing, vigor, 

disease incidence, ind/or crown position. 

Row thinning consists of removing rows of 

3 plant 1t 1011 without regard to other consideration~. 'IkaAs usually lnvolves cutting either 

every sc cor,c. or third row. 
Many potential benefits are not achieved 

in row thinning. Since trees removed are 

chosen purely by their presence in a row, 

improvement in quality or size is entirely 

by chance. Damage from ice and wind is common 

in row-thinned stanas and volume growth is 

typically less than in selectively thinned 

pine stands (Belanger and Brendes 19613, Grano 

1971, Feduccia 1983). 

In the past, row thinning was sometimes 

considered to be more practical than selective 

thinning, and by some perhaps the only economic 

approach to thinning. Row thinning is readily 

accomplished with a wide variety of machinery 

(Anderson and Granskog 1974, Cranskog 1982). 

However, with the development of small, highly 

maneuverable machinery, some mechanized systems 

for selective thinning can approach the efficiency and cost effectiveness of row thinning 

(Lanford and Stokes 1982, Stokes and Lanford 

1982). 

Systems are in use which are not entirely 

row or selective in application, but which 

employ a pattern of fifth or seventh-row removal 

combined with selective removal of stems from 

rows between the resulting access corridors. 

These systems employ standard-sized skidders 

in the wide corridors and either small fellerbunchers or chain saws for felling (Stokes 

and Lanford 1982, Lanford and Stokes 1985). 

The objectives of this study are twofold. 

The first is to document and determine differences in major silvicultural and ecological 

effects of representative mechanized firstthinning systems. The second objective is 

to determine the economic ramifications of 

growth and site impacts of representative 

mechanized thinning systems. 

METHODS 

Two types of study approaches are being 

taken in this project. One consists of a 

side-by-side installation of two mechanized 

thinning treatments with control plots left 

unthinned. The other approach consists of 

installing study plots on sites with thinning 

operations as they are actually performed 

in the field. 

Studv Areas 

Research plots have been established in 

three plantations to date. One thinning treatment was applied to two moderately to well 

drained plantaticns on the Upper Coastal Plain 

in Conecuh and Butler counties, Alabama (~oswell 

fine sandy loam and Luverne fine sandy ioamSmithdale sandy loam, respectively). A side-byside installation of study plots to monitor 

two separate mechanized thinning treatments 

has been established on a moderately well 

drained plantation on the Upper Coastal Plain 

of Conecuh County, Alabams (Annemaine fine 

sandy loam). The loblolly pine plantations 

examined had site indices of approximately 

85 feet (base age 25) and ranged in age from 

15 to 17 years. Specific site selection criteris 

are as follows: 

no previous thinning 

minimum tract size of 43 scres 

medium to high site index 

maximum of 25 percent slope 

stand age of approximately 15 years 

pre-thinning density of approxrmately 

600 trees per acre 

removal of 250-350 trees per acre 

maximum of 150 non-pine stems per 

acre greater than 4 inches in diameter 

at breast height 

Harvesting Systems 

The two thinning systems chosen for study 

were selective forwarder and fifth-row skidder 

systems. Both systems are presently used 

in the Southeast. The forwarder system with 

its almost complete selectivity represents 

one end of the spectrum of feasible mechanized 

thinning systems, The fifth-row skidder system 

represents thinning systems which are neither 

purely row nor selective in application. 

On the three sites where the selective forwarder system was used, small feller-bunchers 

cut 10 feet wlde access corridors approximately 

one and one-half chains apart, then thinned 

selectively between corridors. In one pass, 

trees were cut from the corridors and on either 

side to half the distance between the next 

corridor, Whole tree bunches were placed 

perpendicular and adjacent to the corridors 

by feller-bunchers. A processing machine 

delimbed and bucked the trees from each bunch 

to seven and one-half-foot logs, stackrng 

the logs next to the corridor, opposite the 

whole tree bunches. Slssh from each tree 

was deposited in the corridor ahead of the 

processor. Subsequently, both the processing 

and forwarding machines were driven over the 

slash covered ccrriaors, minimizing slash 

build up and soil damage. A forwarder then 

picked up and trsnsported the logs to a graded 

road or deck, where it unloaded directly to 

a trailer or a pile for later losaing. 

Where the fifth-row sKrdder wss used, skid 

trails were estabilshed by removlng every 

fifth plantation row uslag s feller-buncner. 

Whole tree bunches were ~ositlonzd in and 

align?d with the sKia trall, and were skidded 

to a graded road or deck by 3 grapple s~ldder. 

~n a second pass, tne feller-buncher selectively 

thlnned two rows to either slde of each skid 

trail, again placing the bcn-hes In the skld 

1 These bunches wer? also skldoed to 

a graded road or deck bhere the whole irees 

were processed into snortwood and Lo3dea on 

-ailers for transport to the mill (r20rinsl;y, 

the trees are gste aeiimbed and loaoea tree 

length). Processing rnacnlnes ~iled slash 

along the sides of the rosds and aecks. Skidders 

were driven over the slash when convenient, 

to compact the slash piles as much as possible. 
Measurements 

Fifty tenth-acre fixed radius plots were 

established in the three plantations. Ten 

of these were check plots which were left 

unthinned. On each plot the following tree 

measurements and observations were made: 

azimuth and distance to plot center 

(for relocation purposes and construction 

of plot maps) 

diameter at breast height 

increment core samples for radial 

growth information 

crown class and ratio 

total height and stem quality 

disease incidence 

amount and location of damage caused 

by logging equipment 

proximity of logging damage to nearest 

high impact stratum (corridor, bunch, 

pile, and skid trail) 

evidence of insect attack 

Soil and site measurements included: 

I. area comprised of each impact stratum 

2, area covered by slash and bare soil 

3. percent slope 

4. species, size, and number of non-pine 

woody stems 

5. soil core samples for bulk density 

and moisture content determination 

6. soil horizon characterization 

In addition to these measurements, extensive 

documentation was performed by video recording 

and photographing the operation of each machine. 

Ihis has aided in the determination of types 

of damage attributable to each machine. 

Measurements were taken prior to harvest 

and immediately thereafter. Yearly measurements are to be continued for at least three 

years. 

Analvtical Procedures 

Once the data base has been expanded to 

encompass information collected from more 

plantations, appropriate statistical procedures 

will be applied to determine the following: 

1, percent of tract in each impact category 

2. amount and degree of damage to residual 

stand as it relates to thinning 

3. relationships between growth and damage 

4. relationships between mortality and 

damage 

5. relationships among tree mortality, 

tree and stand characteristics, and 

thinning pattern 

6. relationships among growth, tree and 

stand characteristics, and thinning 

pattern 

7. means and degree of variability of 

soil bulk densities for each impact 

category 

RESULTS AND DISCUSSION 

Stand Characteristic Changes 

The three plantations examined were planted 

at 908, 726, and 871 trees per acre. Prior 

to thinning there were 669, 468, 542 (side-byside forwarder treatment site), and 525 (side-byside skidder treatment site) trees per acre. 

Post-thinning inventories showed residual 

stand levels to be 262, 173, 258, and 248 

trees per acre, respectively (Figure 1). 

The amount of pre-thinning stand basal area 

ranged from 128 to 177 square feet per acre 

and residual stand basal areas varied from 

64 to 88 square feet per acre (Figure 2). 

Pre-thin to post-thin increases in average 

tree diameter at breast height ranged from 

0.58 inch to 1.25 inches. The largest increase 

was observed in a stand where the forwarder 

system was applied, and the smallest increase 

was seen in the stand where the fifth-row 

skidder system operated (Figure 3). This 

possibly reflects a difference resulting from 

the lower degree of selectivity in the skidder 

system. 

Harvesting Impacts and Damage 

Impact Areas 

Corridors, skid trails, and areas where 

whole tree bunches and log piles were placed 

were classified as high impact strata. In 

the stands that the selective forwarder system 

thinned, 37, 25, and 30 percent of those stands' 

areas were in high impact strata. Eighteen 

percent of the stand thinned by the fifth-row 

skidder system was comprised of skid trails 

(percentage does not reflect the area in decks) 

(Figure 4). Ocular estimates of light slash 

(that being less than 1 foot in depth) and 

heavy slash (that being greater than 1 foot 

in depth) were obtained from each corridor 

and skid trail. On average, the amount of 

corridor area covered in slash in the forwarder 

system stands was 28 percent for light slash 

and 51 percent for heavy slash. Estimates 

of slash in the skid trails of the stand thinned 

by the fifth-row skidder method were smaller 

(slash in the skid trails was comprised of 

limbs and tops broken off during skidding, 

and hardwood and understory plant debris). 

An average of 65 percent of the skid trail 

area was covered by light slash, and only 

5 percent by heavy slash. This was expected 

because the skidded trees were processed outside 

of the thinned stand, and most of the slash 

was piled on the sides of the surrounding 

roads and decks. 
STAND SIOGKlNC 

1.0 

Figure 1.--Average loblolly pine stoekrng 

by site and thinning system. Sites 1 and 

3 were 15 years old, and slte 2 was 17 years 

old. 

STAND BASAL AREA 

Po0 . 

1-FVRWWtDEM 2-FDWDEII J--PBRWDOI FSUlWER 

WIN 

Figure 2.--Averagtt loblolly pine basal area 

by site and thinning system. Sites 'I and 

3 were 15 years old, and site 2 was 17 years 

old. 

AVG STAND DIAMETER 

Figure 3.--Average pine stand dbh by slCz 

and thinning system. Sites 1 and 3 were 13 

years old, and siLe 2 was 17 years old, 

AREA OF IMPACT STRATA 

45, 

I 37.0 1 

I-fWRWARDER 2-FORWARDER FFO 

Figure 4.--Percent of stand area comprised 

of high impact strata (C = corridors, P = 

piles, B = bunches, S = skla tralls, T = total) 

by site and thinning system. 

Soil Bulk Densities 

Three bulk density samples were extracted 

from the surface of each observable stratum 

on each plot. Pre- and post-thinning bulk 

density values for a11 test sites collectively were compared by stratum. Significant 

increases in compaction (Scheffeis multiple 

comparison procedure) were noted only in the 

visible tire tracks in corridors and skid 

trails (Figure 5). The visible tire tracks 

of the corridors and skid trails represented a small amount of the total area of the 

stands sampled (less than three percent). 

Subsequent analyses compared pre- and postthinning bulk denslty values by stratum for 

eac6 test site individually. These showed 

that only two of the four test sites had a 

significant increase in compaction. The significant increases were found to be in the 

visible tire tracks of one forwarder treatment 

site and the visible tire tracks of the skidder 

system treatment site (Figure 6). 

A comparison of bulk density values for 

the side-by-side test site (where forwarder 

and skidder systems operated in the same stand) 

showed no significant differences in compaction 

among 10 strata (Figure 7). However, bulk 

density values obtained in the tire tracks 

of the corridors and skid trails were the 

highest, Strata represented included: 

If. 

'Is. 

2f. 

2s. 

3f. 

3s 

4f 

4s. 

5. 

r 

0. 

Pre-thinned plots (forwarder system) 

Pre-thinned plots (skidder system) 

Thinned area of plots (forwarder system) 

Thinned area of plots (sk~dder system; 

Corridors - in tire tracks 

Skid trails - in tire tracks 

Corridors - between tire tracks 

Skrd trails - betwaen tire tracks 

Whole tree bunch areas 

Log pile areas 
Altnough in some cases bulk aensities signiflcantly increased, compaction rates were low. 

It has been generally accepted that 1.4 g/crn3 

1s the value that must be reached before growth 

losses occur in loblolly p:ne (Lull 1959, 

Mitchell ana otners 1982). Eone of the bulk 

density vzlues of the existing four sites 

approach this level of compaction. The lack 

of serious compaction can be explained in 

part by the low soil moisture percentages 

(wet weight) which ranged from 52.7 to 17.0 

for all Lest sites. 

AVG BULK DENSITY BY SIWTUM 

Figure 5.--Average bulk density values by 

stratum for all test sites collectively. 

Stratum 1 = pre-thinned sites, 2 = thinned 

area of sltes, 3 = corridors and skld trails 

(in tlre tracks), 4 = corridors and skid trails 

(between tlre tracks), 5 = whole tree bunches, 

6 = log piles. * Denotes a significant increase 

in compaction from the pre-thinned test sites 

(alpha level equal to 0.05). 

AVC BULK DENSIN BY SITE AND STRATUM 

Frgure 6.--Average bulk denslty values by 

srte ~qd str~turc. Siratufi 1 = pre-tbinned 

plots, 2 = Lrl,nr:~a ,LL* of plots, 3 = eorrrdors 

or s~ld Lr9i15 jtlre LL~CKS), 4 = corridors 

cr skid trails (bet~cen tracks), 5 = whole 

tree bunches, 6 = log piles. * Denotes a 

significant Increase Ln compaetlon from the 

pre-thinned Lest plotc (31pha level equal 

to 0.05). 

AVG BULK DENSITY BY STWTUM 

1.s 7 ~-ff-~ +BR slm 

1 

Figure ?.--Average bulk density for side-by-side 

test sites by stratum. Stratum 1 = pre-thlnned 

plots, 2 = thinned area of plots, j = corridors 

or skid trails (tire tracks), 4 = corrrdors 

or skid trails (between tracks), 5 = whole 

tree bunches, 6 = log piles (f = forwarder 

system, s = skidder system). None are significantly different from pre-thinning values. 

Tree Damage 

The percentage of residual trees damaged 

averaged 20.6, 18.5, and 9.7 for the stands 

thinned by the forwarder system (Figure 8). 

In the stand thlnned by the fifth-row skldder 

system, 13.7 percent of the residual trees 

were damaged. Average scar sizes for 311 

stands ranged from 71.7 to 20.4 squdre inches 

(Figure 9). The aversge sclr are3 per d3xaged 

tree in the forwarder system stands wss 34.6, 

18.4, 2nd 14.6 square inches, whereas that 

in the skidder system stand was 31.6 squdre 

inches. 

RESIDUAL TREES DAMAGED 

Figure 8.--Percent of residual trees visibly 

darnsg~-d by logging equipment (feller-bunchers, 

process+rs, forwarders, skldders) for each 

site and thinriing system. 
AVERAGE SCAR SIZE 

Figure 9.--Average scar size caused by logging 

equipment (feller-bunchers, processors, forwarders, skidders) by site and thinning system. 

SUMMARY AND CONCLUSIONS 

Goals, methodology, and preliminary results 

have been presented. In the future, continued 

remeasurement of existing research plots and 

measurement of additional installations will 

provide a more complete data set. This larger 

data set will be analyzed using statistical 

procedures, enabling the researchers to identify 

trends within the two thinning systems. Much 

of the existing data represent information 

concerning the siivicultural impacts of the 

mechanized first-thinning systems. Additional 

data collection and further analyses will 

be used to compare the ecological and economic 

consequences of the different thinning systems. 

ACKNOWLEDGEMENT 

The authors wish to express their appreciation 

to the Mississippi Agricultural and Forestry 

Experiment Station for providing funding for 

this project through a subgrant of the United 

Ststes Dep3rtmmt of Agriculture's Specisl 

Grsnts Progrsm. Sincere thsnks is extended 

to Union Csrnp Corporltion, Rocky Creek Logging 

Company, Leary and Owens Equipment Company, 

Inc., and Timberjack, Inc, for their cooperation 

in this endeavor. 

LITERATURE CITED 

Anderson, W.C., and J.E Granskog. 1974. Mechanized row-thinning systems in slash pine 

plantations. USDA For. Ser., For. Res. Pap. 

SO-103. 12 pp. 

Belanger, R.P., and E.V. Brender. 1968. Influence 

of site index and thinning on the growth 

of planted loblolly pine. Ga. For. Res. Pap. 

57. 7 pp. 

Blackwelder, R.H. 1982. Economics and silviculture of commercial thinning. In: Proc., 

Symposium on the Loblolly Pine Ecosystem 

(East Region). H.C. St, Univ. School of 

For, Resources, Raleigh and USDh For. Ser., 

S.E. -,;=r. Sta,, AsPAevli *:a pp. ?46-/:2. 

Clason, T.R. 1962. Tninning influences on 

individual tree growth and development in 

a lobiolly plne ;L?n+sLion. In: Proc., Workshop 

on Thinning Southern Pine Plantations. Forestry 

and Harvesting Training Center, Long Beach, 

Miss. pp. 56-67. 

Feduccia, D.P. 1983. Thinning pins plantations. 

Forest Farmer, Sept., 19E3. 

Grano, C.X. 1971. Growth of planted loblolly 

pine after row and selective thinning. USDA 

For. Ser. Res. Note SO-123. 3 pp. 

Granskog, J.E. 1982. Performance of four row 

thinning systems using three types of harvesters. In: Proc., Workshop on Thinning Southern 

Pine Plantations. Forestry and Harvesting 

Training Center, Long Beach, Miss. pp. 82-104. 

Knight, H., and R.M. Sheffield. 1980. Thinning 

opportunities in pine plantations in the 

Southeast during the 1980's. In: Proc., 

Workshop on Thinning Southern Pine PlantationsIntegrating Economics and Biology. Forestry 

and H3rvesting Trsining Center,Long Beach, 

Miss. pp. 18-26. 

Lanford, E.L., and B.J. Stokes. 1982. Biologically based thinning systems: state of 

the art. In: Conf. Proc., Tech. Assoc. Pulp 

and Paper Industry, Res. and Dev. Div., 

Asheville, N.C., 1982. pp. 281-286. 

Lanford, B.L., and B.J. Stokes. 1985. Techniques 

for silvicultural thinning. In: Proc., Workshop 

on Thinning Southern Pine Plantations. Forestry 

and Harvesting Training Center, Long Beach, 

Miss. 

Lull, H.W. 1959. Soil compaction on forest 

and range lands. USCA For. Serv., Misc. Pub. 

no 768. 

Mann, W.F., Jr., 2nd D.P. Feduccis. 1976. Tree 

sizes harvested In different thinnings-another 

look. USCA For. Ser. Res. Pap. SO-131. 6pp. 

Mitchell, M.L., A.E. Hassan, C.B. Davey, and 

J.D. Gregory. 1982. Loblolly pine growth 

in compacted greenhouse soils. Trans. ASAE 

25 : 304-307, 31 2. 

Stokes, B.J., and 9.L. isnford. 1982. Patterns 

and equipment for selective thinning. In: 

Proc., Workshop on Thinning Southern Pine 

Plantations, Forestry ~nd Harvesting Tr3ining 

Center, Long Beach, Miss. pp. 105-118. 

Wllker, L.C. 1982. Thinning the southern pine 

plantation: an ovzrview. In: Proc., Workshop 

on Thrnning Southern Pine Plantations. Forestry 

and Harvesting Training Center, Long beach, 

Miss. pp. 1-10. 
DEVELOPmMT OF IMTEWEDIATE AND SUPPRESSED 

Abstract.--Eighty-two intermediate and suppressed loblolly 

'-nus taeda L.) trees, ranging from 1.6 to 9.7 inches 

d.b.h. and 11 to 43 years of age were selected before a 

release cutting. The following 10 variables were measured 

for each tree: (I) height, (2) d.b,h., (3) age, (4) radial 

growth last 5 years, (5) crown volume, (6) percent live 

crown, (7) stem diameter at base of crown, (8) hardwood 

competition index before release, (9) pine competition 

index before release, and (10) pine competition index after 

release. All hardwoods on the area were injected following 

release cutting. Response of trees to release was 

evaluated by measuring d.b.h., basal area, stem diameter 

at base of crown, and height growth after five growing 

seasons. Average d.b.h, of the 78 surviving trees 

increased by 2.4 inches over the 5-year period. This 

represents an increase in basal area of 125 percent. A 

stepwise regression indicated that the two most important 

variables associated with diameter growth were diameter at 

base of crown and percent live crown (~~10.53). Trees 2 

inches or less in diameter at base of crown, with 20 

percent or less live crown, can be expected to show poor 

response to release. 

INTRODUCTION 

The crown classification system most widely 

used in the United States categorizes trees as 

dominant, codominant, intermediate, or suppressed 

(~aniel et al, 1979). In thinning operations, 

intermediate and suppressed trees are often 

removed, leaving the better formed dominants and 

codominants. Often, however, it may be desirable 

to leave an intermediate or suppressed tree to 

occupy the site where mature trees have been 

harvested. 

It is generally agreed that the live-crown 

ratio of a tree should be about 40 percent for 

optimum production of clear wood (chapman 1953; 

Labyak and Schumacher 1954). If the ratio is 

allowed to decrease to 30 percent or less, the 

general reduction in vigor may cause substantial 

loss in diameter growth. No clear guidelines 

Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2/ Principal Silviculturist, Forestry 

Sciences Laboratory, #onticello, Arkansas, 

Southern Forest Experiment Station, USDA Forest 

Service, in cooperation with the Department of 

Forest Resources and the Arkansas Agricultural 

Experiment Station. 

have been available, however, to enable timber 

markers to ascertain which intermediate and 

suppressed trees are capable of recovering and 

subsequently make good volume growth following 

release, Consequently, a study was installed to 

determine the ability of poorly formed, 

intermediate or suppressed loblolly pines with 

small crowns to recover and develop into 

acceptable crop trees when released, 

METHODS 

The study was installed during the winter of 

1979-80 in an uneven-aged loblolly-shortleafhardwood stand located in Ashley County, 

Arkansas. The site index for loblolly pine was 

about 90 feet at age 50. Pines ranged from 

seedlings to 18 inches d.b.h, in size, with a 

basal area of approximately 80 square feet per 

acre. Hardwoods were up to 15 inches d.b,h. and 

had a basal area of approximately 30 square feet 

per acre. The stand had been cut back to 

stocking levels of 10 to 50 percent for pine for 

another study. Stocking levels were based on 

guidelines used by the USDA Forest Service's 

Forest Survey. For this study, 82 loblolly pines 

were selected from the isolation strips of that 

study, before release. Ten measurements were 

taken for each tree at the time of selection: 
Height 

D*b*h* 

Age 

Radial growth last 5 years 

Crow volume 

Percent live crown 

Stem diameter at base of crown 

Hardwood comptition index before release 

Pine competition index before release 

Pine eomptition index after release 

No measure~ents were made of the hardwood 

csmpetltlsn index after release because all 

hardwoods were killed by injection with a 

herbicide when the study was installed. 

Competition indices were determined as described 

by Daniels and Burkhart (1975) and computed as 

follows : 

where CIi = Competition index of the ith 

tree, 

D = d.b.h. (in), 

DIST = Distance between subject tree i 

and jth competitor, and 

n = Number of competitors counted 

with 10 BBF prism. 

The average age of the 78 surviving trees was 

26 years when the study was installed, with ages 

ranging from 11 Lo 43 years and d.b,h. ranging 

from 1,6 to 9.7 inches and averaging 4.8 inches. 

Response of trees to release was evaluated 

for each of four dependent variables: d.b.h., 

basal area, stem diameter at the base of the 

crown, and height growth after five growing 

seasons. Stepwise regression analyses were 

employed to determine the relationship of the 10 

independent variables listed above to the four 

dependent variables measured after the 5-year 

period. 

Camera points were established and pictures 

were taken of each tree when the study was 

installed and after five growing seasons. 

RESULTS 

Diameter growth of the study trees was 

surprisingly good for the 5-year period following 

release. Average d,b.h. increased by 2.4 inches 

for the 78 surviving trees, Since the trees 

averaged 48 inches d,b,h, initially, this 

represents an increase in basal area of 125 

percent for the 5-year period, or a 25 percent 

increase per year, This is even more dramatic 

when the suppressed condition of the trees is 

considered, along with the fact that average age 

of trees was 26 years when the study was 

installed, 

Figwes 1-4 provide visual examples of the 

suppressed condition of trees when the study was 

installed and the extent of recovery 5 years 

after release. The most evident feature in these 

photographs is that trees with extremely small, 

thin, misshapen crowns managed to recover quickly 

and start making phenomenal pgro wth almost 

immediately. Because most trees, with the exception of the four that died, responded dramatically to release, none of the variables measured 

when the study was installed proved to be highly 

reliable predictors of a tree's ability to 

recover and make good growth* Moreover, there 

was no apparent relationship between the 

variables and mortality of the trees that died, 

Nevertheless, a stepwise regression was run 

to determine the importance of the 10 variables 

measured in predicting 5-year d,b.h. growth. 

Table 1 lists the order in which the 10 variables 

appeared and the corresponding R2 values. Radial 

growth for the 5-year period preceding 

installation of the study was the best single 

predictor, with an ~2 of 0.450. When two 

variables were used, percent live crown and stem 

diameter at the base of the crown were the best 

predictors, but the R~ was only 0.531. Extending 

the number of variables to three or four involved 

height and pine competition index after release. 

Little was gained by using more than four 

variables. 

When a stepwise regression for basal area 

growth was run, the HZ values were somewhat 

higher. The three best predictors in this case 

were height, stem diameter at base of crown, and 

pine competition index after release, which gave 

a combined R~ of 0.773. It is not surprising 

that a relatively high ~2 value for basal area 

growth was obtained with these variables because 

basal area growth is strongly dependent on 

d.b,h., and d.b.h, is s t r o n g l y c o r r e l a t e d with 

height (r = 0.92) and diameter at the base of 

crown (r = 0.96). Factors that were relatively 

unimportant in relation to d.b,h, growth and 

basal area growth included initial d.b.h., age, 

and competition indices before release. It is 

interesting to note that trees were able to 

recover and make good growth regardless of size, 

age, or previous competition, as evidenced by 

figures 1-4. 

Regressions for stem diameter growth 3t the 

base of live crown resulted in very low R 

values. The most important single independent 

variable was initial stem diameter at base of 

crown, which resulted in an RZ of 0.292, The two 

best predictors, combined, were initial d.b,h. 

and percent live crown, with an RZ of only 0.397. 

Again, competition indices before release were 

relatively unimportant, 

A regression for 5-year bight growth showed 

the best predictor to be percent live crown, 

with an F12 of 0.200. Initial height, radial 

growth the last 5 years, age, crown volume, and 

stem diameter at base of the crown increased the 

R~ slightly, but when the four best predictors 

were used, the ~2 was only 0.376. 
Figure 1,--Left, 29-year-old tree, 3.1 inches d.b.h. at time of release; 

right, 5.9 inches d.b.h. 5 years later. 

Figure 2,--Left, 30-year-old tree, 5.1 inches d.b.h. at tiw of release; 

right, 8,3 inches d.b,h. 5 years later. 
Figure 3.--Left, 14-year-old tree, 5.3 inches d.b.h, at time of release; 

right, 8.0 inches d.b.h. 5 years later. 

Figure 4,--Left, 17-year-old tree, 3.0 inches d. b.h, st time of rele t .#>; 

right, 6.3 inches d.b.b. 5 years later, 
Table 1.--Relative importance of variables 

measured on d.b.h, grow~h after 5 

years. 

Numberof Adjusted Identif icatio 

variables ~2 of variables~? 

Height 

Initial d.b.h. 

Reciprocal of age 

Radial growth last 5 years 

Crown volume 

Percent live crown 

Stem diameter at base of crown 

Hardwood competition index before release 

Pine competition index before release 

Pine competition index after release 

Hence, d.b.h. growth, where the two best 

predictors gave an ~2 of 0.531, appears to be 

substantially more reliable for use in 

determining a tree's ability to recover than 

height growth. 

Because diameter at the base of the crown and 

percent live crown were the two best predictors 

of d.b.h, growth (and these two variables are 

relatively easy to estimate quickly and 

accurately), it is suggested that they be used as 

a guide in determining the ability of a 

suppressed tree to recover when released. The 

prediction equation for estimating 5-year d.b.h. 

growth ($) following release is: 

where DCB = diameter at base of crown in inches, 

and 

CRPCT = percent live crown. 

Figure 5 shows predicted 5-year d,b,h. growth 

where the independent variables are stem diameter 

at base of crown and percent live crown. This 

graph indicates that approximately 1 inch of 

d.b.h. growth would be expected over a period of 

5 years for trees with a stem diameter at the 

base of crown of 2 inches and a live-crown ratio 

of 20 percent. Duerr et al. (1956) considered 

trees that grow 1.0, 1.5, and 2.0 inches in 

d.b.h. over a ?-year period to be in poor, 

medium, and high vigor classes, respectively. 

Hence, trees 2 inches or less in diameter at base 

of crown and with a live-crown ratio of 20 

percent would be judged in the low vigor class 

and poor candidates for crop trees, Trees 2.5 

inches in diameter at base of crown and with a 

live-crown ratio of 30 percent are in the medium 

vigor class (estimated d.b.h. growth of 1.5 

inches in 5 years) and will probably make 

suitable crop trees. Trees described here as 

being in the low vigor class, with small 

diameters at base of crown and low live-crown 

ratios, are commonly referred to as "whips." 

CONCLUSIONS 

Perhaps the most important information gained 

from this study is that suppressed loblolly pines 

15 to 40 years old, with small, thin crowns, can 

recover quickly and make rapid growth following 

release. Though none of the variables measured 

proved highly reliable in predicting a tree's 

ability to recover, diameter at base of crown and 

percent live crown are two of the best and are 

the easiest to estimate quickly while marking 

trees. 

LITERATURE CITED 

Chapman, H. H. Effects of thinning on yields of 

forest-grown longleaf and loblolly pines at 

Urania; La. Journal of Forestry. 51 : 16-26; 

1953 

Daniel, T. W.; Helms, J. A*; Baker, F. S. 

Principles of silviculture. 2nd ed. New York: 

McGraw-Hill Book Co.; 1979. 500 p. 

Daniels, R. F.; Burkhart, H. E. Simulation of 

individual tree growth and stand development in 

managed loblolly pine plantations. Virginia 

Polytechnic Institute, Division of Forestry and 

Wildlife Resources, FWS-5-75; 1975. 69 p. 

Duerr, W. A.; Fedkiw, J.; Guttenberg, S. 

Financial maturity: a guide to profitable 

timber growing. Tech, Bull. 1146. Washington, 

DC: U.S. Department of Agriculture; 1956. 74 p. 

Labyak, L. F.; Schumacher, F. X. The contribution 

of its branches to the main-stem growth of 

loblolly pine. Journal of Forestry. 52:333-337; 

4954 
STEM DIAMETER AT BASE OF CROWN (inches) 

Figure 5.--Relationship of 5-year,d. b.h. growth to diameter at base of crown and 

percent live crown. (Y = -0.14 + 0.36 (DVB) + 0.033 (CRPCT)). 
TEN-YEAR GROtdTH OF RED M?D WHITE OAK CRW TREES POLLWING 

THINNING AKD FERTILIZATION IN THE BOSTON 

MOUNTAINS OF SAS; 

Abstract ,--A thinning and fertilization study of 50-yearold northern red oak (Quercus rubra L.), black oak (9. 

velutina Lam,), and white oak (9. alba L.) was initiated in 

the Boston Mountains of Arkansas in the spring of 1975. 

Fertilizer applications of a nitrogen and phosphorus 

combination were broadcast at two levels to individual oaks 

that had received thinning or nonthinning treatments. Both 

levels of fertilization increased diameter growth of oaks in 

thinned and nonthinned stands . Maximum response to 

fertilization occurred during the first and second years 

after treatment, Response continued through the sixth year 

for white oak and through the eighth year for red oaks. A 

significant diameter growth response to thinning occurred 

during the third growing season after treatment for red and 

black oaks and the fifth growing season for white oak. From 

this point, the rate of annual diameter growth for all oaks 

in thinned stands increased annually through the tenth year. 

INTRODUCTION 

Several hundred thousand acres of forest land in 

nurt hern ~rkarls as support overs to eked , even-aged , pole-sized scands of oaks and associated species. 

Although rlarly stands are on medium-to-good sites 

(site Index of 60 to 70 feet at 50 years), diameter 

growth averages only about 1 inch in 10 years. 

Since there are very few outlets for small diameter 

hardwoods, there has been very little intermediate 

cutting in these stands . However, because demands 

for hardwood sawt imber are increasing and 

inventories of mature sawtimber are small, some 

lard nanagers have begun noncommercial thinning 

prograns to accelerate growth of potential crop 

trees. Fertilization may further stimulate growth 

of crop trees. Kesearch has shown that northern 

red (ouercus -- rubra L.), black (2. velutina lam.), 

and white (0. alba L.) oaks will respond to 

nitrogen (N) atid phosphorus (P) fertilization. 

Uiatieter growth of fertilized red oaks has been 

siiowri to increase by 45 to 70 percent and white oak 

about 60 ercent. Ked oaks responded more to 

higher levels of N, while white oak produced about 

the same response to medium and higher levels of N 

(Craney and Pope 1978a, 19785; Graney 1983). In 

this paper, 10-year growth responses of red oaks 

(northern red and black oaks) and white oak in the 

Boston Mountains of Arkansas are summarized. 

Objectives uerr to detennxi~e how fertilizer 

applications affected diameter growth in thinned 

and nonthinned stands and to determine the effect 

of thinning on the diameter growth response to 

fertilization. 

ME T HODS 

Study Area 

The Boston Mountains are the highest and 

sou thernmos t member of the Ozark Plateaus 

physiographic province (fig. 1). They form a band 

30 to 40 miles wide and 200 miles long from north 

central Arkansas westward into eastern Oklahoma. 

Elevations range from about 900 feet in the valley 

bottoms to 2,500 feet at the highest point. The 

plateau is sharply dissected, and most ridges and 

spurs are flat to gently rolling and are generally 

less than one-half mile wide. Mountain slopes 

consist of an alternating series of steep simple 

slopes and gently sloping benches. 

Rocks in the area are sedementary and are of 

Pennsylvanian and Mississippian age, consisting of 

alternating horizontal beds of sands tones and 

shales. Annual precipitation averages 48 inches, 

with March, April, and Way being the wettest 

months. Extended summer dry periods are common, 

and autumn is usually dry. The frost-free period 

is normally 180 to 200 days long. 

l/paper presented at Southern Silvicultural 

JXeTecrch Conference, i?tlanta, Georgia, November 

4-6 1986. 

21Prilicil>al Silvicuittirist , Southern Forest 

~x';;eriijent Station, G.S. k)epartr,lent of ,Lr:riculture, 

Forest Service, Fayetteville, Rbt 727G1. 

Three study areas were selected in overstocked 

stands on mountain benches that range from 2 to 3 

chains wide. Soils are deep, well-drained , medium-textured members of the Nella and Leesburg 

series (Typic Paleudult s) . They are derived from 

sandstone and &hale colluviurn and rated medium to 

high in productivity . 
MISSOURI 

Figure 1. --The Bos ton Mountains of Arkansas. 

Sample Trees 

In each stand, 48 red oak and 48 white oak crop 

trees were selected for the thinning and fertilizer 

treatments. Trees from each species group were 

arranged into 16 sets of 3 trees each, lifembers of 

each 3-tree set were uniform in diameter, crown 

size, and height and were located on essentially 

the same site conditions. Thin or nonthin 

treatments were randomly assigned to each 

diameter measurement point was identified by a 

painted band on each tree. Increment cores, 

extracted from the north, east, south, and west 

sides of each tree, were sealed in soda straws. 

These were used to determine tree age and to obtain 

a measure of past growth. Past annual radial 

growth was measured to the nearest 0.01 inch using 

a binocular microscope. Total height was also 

recorded for each tree. 

three-tree set, and three fertilizer treatments Thinning Treatment 

were randomly assigned to trees within each set. 

In total, there were 144 red and black oaks and 144 Basal area around each sample tree was determined 

white oaks at 3 locations. with a prism and was reduced to about 70 ft2 by 

removing two major competitors and several smaller 

Tree Measurements trees. Thinning was completed in March 1975. 

Average tree and stand characteristics following 

Diameter at breast height (d.b.h.) of each sample thinning in 1975, along with 10-year diameter and 

tree was measured to the nearest 0.01 inch. The basal area values, are shown in table 1. 

Table 1.--Mean stand and tree characteristics for red and white oak thinned 

and nonthinned treatments at the beginning and ending of the study 

After Treatment 10-year Change 

Site Basal Basal 

Treatment Age Index D.b.h. Area D.b.h. Area 

- years - feet inches ftZ/acre inches ftZ/acre 

Red Oak 

Thinned 50 6 2 8.18 68 9.93 8 2 

Nonthinned 50 62 8.48 120 9.73 115 

White Oak 

Thinned 52 5 9 8.26 66 9.98 82 

Nonthinned 52 59 7.89 123 9.24 118 
Fertilizer Treatments Table 2 .--Mean annual diameter growth response of 

red and white oaks to thinninga/ 

A combination of two fertilizers, ammonium 

nitrate (34-0-0) and diamaoniun phosphate (16-46-0) 

was used. Fertilizer treatments were: (1) No 

fertilizer (nonfertilized), (2) 200 Ibs N + 45 lbs 

P per acre (200 Ib treatment), and (3) 400 lbs N + 

45 lbs P per acre (400 Ib treatment). Fertilizers 

were surface broadcast i n l a t e April 1975 on a 0.01 

acre circular plot surrounding each tree. 

Data Analysis 

The study design was a split-plot with thinning 

representing the whole plots and fertilizer 

treatments the subplots. Data were analyzed by 

analysis of covariance with mean annual diameter 

growth for the 5-year period prior to treatment 

( 1970-74) as the covariate. Differences among 

adjusted treatment means were tested using Duncan's 

multiple range test . 

RESULTS 

Response to Thinning 

Red and white oak sample trees produced an 

immediate positive response to thinning, and the 

rate of annual diameter growth generally increased 

throughout the 10-year period of the study (table 

2). Levels of response to thinning were greater 

and more apparent in the fifth through tenth years 

when fertilizer response declined and growth rates 

of nonthinned trees slowed to pretreatment levels 

or less. 

Diaxeter growth rates of thinned red oaks were 

significantly greater than rates of nonthinned 

trees from the third through the tenth year and 

averaged more than a 75-percent increase over the 

last 5 years of the study. Over the 10-year 

period, t ninning increased red oak diameter growth 

by about 40 percent. 

White oak responded positively to thinning, but 

the level of response was lower than that observed 

for tiLc red oaks (table 2). While differences in 

dia~aeter growth be tween thinned and nonthinned 

white oaks were at or near significant levels 

through the fourth year following thinning, growth 

differences between nonf ert ilized trees receiving 

thin or nonthin treatments were not apparent until 

the fifth year. White oak produced the greatest 

response from years 6 through 10 where thinned 

trees averaged about 50 percent greater diameter 

growth than nonthinned trees. 

1:esponse to Fertilization 

Fertill;.,,tlon significantly increased diameter 

growth oi r-cu and white oaks over the 10-year 

period of tile study, but the response varied 

between species and was influer~ced by the thinning 

t reataent . 

RED OAK WHITE OAK 

Year Nonthinned Thinned Nont hinned Thinned 

Mean 0.125 0.175" 0.135 0.142" 

a/l)ata averaged over all fertilizer rates and - 

adjusted for differences in diameter growth using 

the 5-year period before thinning. 

b/* indicates statistically significant at P(0.05. - 

Red Qk 

Thinned red oaks produced the greatest overall 

response to fertilization and were the most 

responsive to the higher level of M (table 3). For 

the 10-year period, mean diameter growth of 

thinned, fertilized red oaks averaged 28 percent 

more than growth of thinned, nonfertilized red oaks 

for the 200 lb treatment and 42 percent more for 

the 400 lb level. Nonthinned red oaks produced 

about the same response to the 200 and 400 lb 

levels and averaged a 38-percent increase in 

diameter growth for each level of N. 

Maximum response to fertilization occurred during 

the first 2 years after treatment. Response 

declined annually but was generally greater than 

nonf ert ilized trees through the ninth and tenth 

years. After the fifth growing season, thinned red 

oaks indicated no difference in response to the 200 

or 400 lb treatments. 

Over the 10-year period, growth response to 

fertilization for thinned red oaks averaged about 

35 percent, slightly lower than the res2onse 

reported for northern red oak in thinned stands in 

New York (Karning 1972) and higher than reported 

for thinned black oaks in the Missouri Ozarks 

(PlcQuilkir? 1982 ), Ten-year increases in diameter 

growth of nonthinned Boston Mountain red oaks 

averaged 38 percent, which was slightly lower than 

observed for red oaks in the Tennessee Valley 

(Farmer and others 1970) and slightly higher than 

increases for northern red oak in West Virginia 

(Lamson 1978, 1980) and scarlet oak in Pennsylvania 

(Ward and Bowersox 1970). 
Table 3.--Mean annual diameter growth resrmnse to fertilization for thinned 

and nonthinned red oaks'/ 

Nont hinned Thinned 

Fertilizer Treatment Fertilizer Treatment 

Year Nonfertilized 200 lb 400 Ib Nonfertilized 200 lb 400 Ib 

Mean 0.100a 0.138b 0.138b 0.142a 0.181b 0.202~ 

l/~ata adjusted for differences in diameter growth during the 5-year period - 

before treatment. 

- 21values in rows follwed by the same letter are not significantly different at 

the 0.05 level. 

White Oak 400 lb treatment, averaging a 40-percent increase 

over the 10-year period, 

In contrast to the red oaks, thinned white oak 

was much less sensitive to the two levels of N White oak produced the maximum response to 

fertilization. Both levels produced about the same fertilization during the first 2 years after 

1 0-year increase, 30 percent (table 4). Nonthinned treatment. Fertilizer response declined annually, 

white oaks produced the greatest response to the but remained significant through the fifth year. 

Table 4 .--Mean annual diameter growth response to fert ilization for thinned 

and nonthinned white o&ksl/ 

Nonthinned Thinned 

Fertilizer Treatment Fertilizer Treatment 

Year Nonfertilized 200 lb 400 1b Nonfertilized 200 lb 400 lb 

Mean 

- l/~ata adjusted for differences in diameter growth during the 5-year period 

before treatment. 

- 2/values in rows followed by the same letter are not significantly different 

at the 0.05 level. 
Mean 10-year response of the thinned and 

nonthinned white oaks to the fertilizer treatments 

was about 33 percent, nearly the same as responses 

for fertilized white oak in Pennsylvania (Ward and 

Bowersox 1970) but ody about one-half the response 

observed for white oak in the Tennessee Valley 

(Farmer and others 1970). 

DISCUS SI ON 

Overall response of red and white oaks to 

fertilization was reduced by the general lack of 

response during the severe drought of 1980. Growth 

of all study trees was affected to some extent, but 

fertilized tr-es suffered the greatest reductions 

in growth (tables 3 and 4). 

Thinned and nonthinned red oaks continued a 

significant growth response to fertilization 

through the ninth and tenth growing seasons after 

treatment, although actual growth rates for the 

nonthinned fertilized red oaks were relatively low. 

While annual diameter growth for thinned and 

nonthinned fertilized white oaks were slightly 

higher than nonfertilized trees over the 4-year 

period following 1980, levels of response were not 

statistically significant (table 4). In that 

fertilized red oaks maintained a fertilizer 

response following the 1980 drought, it is probable 

that the 5-year response will be the maximum white 

oak response for the 200- and 400-lb levels of N 

applied in this study. 

Initial response of red and white oaks to 

thinning was relatively small, but differences 

be tween thinned and nont hinned trees increased 

rapidly af ter the third to fifth year. Annual 

diameter growth of thinned and nonfertilized red 

and white oaks continued to increase through 1984, 

while growth of nont hinned arid nonfe rt ilized trees 

declined to below pretreatment levels (fig, 2). 

Differences in early levels of response to 

thinning by red and white oaks are probably due to 

differences in initial crown size and competitive 

position in these overstocked stands. On the same 

site, site index values for northern red and black 

oaks usually average 5 or more feet greater than 

white oak. The red oaks attain dominant crown 

positions and develop and maintain relatively large 

crowns. In mixed stands, most white oaks occupy 

lower crown positions and will suffer continuous 

reduction in crown size due to crowding but will 

persist for many years with very low rates of 

growth. As indicated by the consistent decline in 

diameter growth prior to thinning (fig. 2), all 

trees needed release, but the red oaks were 

generally in better condition to respond than were 

the white oaks. 

Diameter growth for nonthinned and nonfertilized 

white oak trees over the period 1970-84 indicates 

the species' ability to survive and grow in these 

dense stands for long periods of time (fig. 2). 

Though generally in a less competitive crown 

position, subjected to intense crowding and 

competition, and possessing very small crowns, 

white oak maintained a fairly consistent rate of 

diameter growth over the 15-year period. 

Nonthinned red oaks, on the other hand, were much 

more sensitive to competition and crowding and 

declined in diameter growth throughout the 1970-84 

period (fig . 2). To maintain reasonably acceptable 

rates of diameter growth in these upland stands, 

red and white oak crop trees will require release 

from crown competition, and release should occur 

before crop trees suffer appreciable reduction in 

crown size. 

The 10-year results of this study indicate that 

diameter growth of pole-sized red and white oaks 

can be significantly increased by thinning and/or 

fertilization. In overstocked stands where crop 

@ BEFORE TREATMENT 

X THINNED 

0 NONTHINNED 

THINNED 

APPLIED NONTHINNED 

I I I I t 

0 70 72 74 76 78 80 82 84 

YEAR 

Pi,,.,, 2.-+lean annual diameter growth of ilolttert?ilized red and white oak crop 

trees before and after thinning. 
trees have been subjected to extended periods of 

severe crowdis, released trees will generally 

produce a positive response within 1 or 2 years 

af ter treatment, but a significant response to 

thinnim may be delayed several years, Annual 

diameter measurements taken in conjunct ion with an 

oak gromh and yield study in the Boston Mountain 

area indicate that free-to-grow red and white oak 

crop trees in 40- to 70-year-old stands on medium 

sites should average diameter ~owth ofabout 0.25 

inch per year. To attain these growth rates, 

thinnings should be initiated before stands become 

overstocked and crop trees suffer appreciable 

reduction in crown size. 

Fertilization with N and P can also increase 

diameter growth of oak crop trees and the increased 

growth rate will persist about 5 years for white 

oak and up to 10 years for red oaks. However, 

while differences in diameter growth be tween 

fertilized treatments were statistically 

significant, it is doubtful that the 10-year 

cumulative increase in diameter (0.3 to 0.5 inch) 

would justify the cost of a single commercial 

fertilizer application in these intermediate-aged 

stands. In considering silvicultural investments 

on these sites, regulation of stand density in 

younger stands should have first priority. 

Fertilization with N and P can also increase 

diameter growth of oak crop trees and the increased 

growth rate will persist about 5 years for white 

oak and up to lO years for red oaks. However, 

while differences in diameter growth be tween 

fertilized treatments were statistically 

significant, it is doubtful that the 10-year 

cumulative increase in diameter (0.3 to 0.5 inch) 

would justify the cost of a single commercial 

fertilizer application in these intermediate-aged 

stands, In considering silvicultural investments 

on these sites, regulation of stand density in 

younger stands should have first priority. 

LITEUTURE CITED 

Farmer, R.E., Jr.; Bengston, G,W,; Curlin, J.W. 

Response of pine and mixed hardwood stands in the 

Tennessee Valley to nitrogen and phosphorus 

fertilization. Forest Science. 16: 130-136; 1970. 

Graney, David L. Effects of thinning and 

fertilization on growth of upland oak stands in 

the Boston Mountains 05 Arkansas : 7-year results. 

In: Jones, Earle P., Jr., ed. Proceedings, 2d 

biennial southern silvicultural research 

conference; 1982 November 4-5; Atlanta, GA. en. 

Tech. Rep. SE-24, Asheville, NC: U.S. Department 

of Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1983 :269-274. 

Graney, D.L.; Pope, P.E. Response of red oaks and 

white oak to thinning and fertilization in the 

Boston Mountains of Arkansas. In: Pope, Phillip 

E., ed. Proceedings, 2d central hardwood forest 

conference; 1978 November 14-16; West Lafayette, 

IN. 1978a :357-369. [Available from Purdue 

University , West Laf aye tte , IN] 

Graney , D. L. ; Pope, P .E. Fertilization increases 

growth of thinned and nonthinned upland oak 

stands in the Boston Mountains of Arkansas. Res. 

Note SO-243. New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1978b. 4 p. 

Karning, Jack J. Nitrogen fertilizer increases 

diameter growth of northern red oak. Journel of 

Forestry. 70(10) :629; 1972. 

Lamson, N. I. Fertilization increases growth of 

sawlog-size yellow-poplar and red oak in West 

Virginia. Res, Paper NE-403. Broomall, PA: U.S. 

Department of Agriculture, Forest Service, 

Northeastern Forest Experiment Station; 1978. 6 

P 

Lamson, Neil I. Effect of fertilization on four 

species in mature Appalachian hardwood stands. 

In : Garrett, Harold E. ; Cox, Gne S. , eds , 

Proceedings, 3d central hardwood forest 

conference; 1980 September 16-17; Columbia, MO: 

1980:449-457. [Available from University of 

Missouri, Columbia, MO] 

McQuilkin, Robert A. Fertilization of oaks in the 

Missouri Ozarks. In: Huller, Robert N., ed. 

Proceedings, 4t central hardwood forest 

conference; 1982 November 8-10; Lexington, KY: 

1982 :79-92. [Available from University of 

Kentucky, Lexington, KY ] 

Ward, W.W.; Bowersox, T.W. Upland oak response to 

fertilization with nitrogen, phosphorus, and 

calcium. Forest Science, 16: 113-120;c 1970. 
P.t4?VTAGE;LZP;XT OPTIONS FOR SOUTRER:; APPALACHIAN ZZ;IRDIdOODS : 

/ THE TWO-AGED STA3D-- 

2 / Donald E. BeckAbstract.--A harvest cut in a good site ccve hardwood stand left 24 

square feet per acre of dominant and codominant trees. The residual 

overstory was primarily northern red oak. follow in^ harvest, the understory was chemically treated. 

After 20 years, the residual overstory has responded well in terms 

of diameter and volume growth with little or no loss in bole aualitv due 

to sprouting. The regeneration that has developed is similar in soecies 

composition and size to that in an adjacent clearcut of the same age. 

Two-aged stands appear to have promise where even-aped stands are not 

desirable for esthetic or other reasons. For example, one might be able 

to maintain continuous mast production on a eiven site by use of the 

two-aged stand. 

INTRODUCTION 

Southern Appalachian hardwood timber can be 

grown most effectively in even-aged stands. However, many owners would prefer an alternative that 

maintains at least some high forest cover continuously on the site. Some are motivated by a desire 

to improve the esthetic appearance of their forests. 

In other cases, the owner would like to maintain 

continuous mast production, e.g., keep oaks of 

seed-bearing age continuously on a site to avoid 

the 20- to 30-year period when even-aged stands 

will produce few, if any, acorns. All-aged stands 

maintained by single-tree selection methods have 

not proved workable (Della-Bianca and Beck 1985). 

Group selection may be a possible alternative. 

However, the recommended group sizes may approach 

the appearance of clearcutting, i.e., up to 2-acre 

groups. The frequent entry needed and the repilted 

difficulty of application also make this alternative less attractive. 

Another alternative may be the two-aged stand 

created by irregular shelterwood (Smith 1986). 

This method is similar to the "two-storied high 

forest" of European foresters (Troup 1955). In 

the irregular shelterwood or two-storied high forest, a stand near midrotation age is cut heavily 

and an underwood, obtained naturally or introduced 

artificially, is allowed to develop. The two 

stories are then allowed to develop together. 

This paper documents the development of one 

two-aged stand throuph the 20th year for the 

younger age class. Some snppestions and guidelines for management under this scheme are offered. 

THE SITE AND STAND 

The 5.2 acre stand is on a northeast-facing 

slope of about 30 percent on the Bent Creek Experimental Forest. Soil is a deep friable loam of 

the Tusquitte series. Site index for oak (Ouercus 

spp.) averaged 85 (Olson 1959). Soecies composition was predominantly chestnut oak (0. prinus L.), 

northern red oak (Q. rubra L.) , and yellow-poplar 

(Liriodendron tulipifera L.) in the overstory with 

an understory of red maple (Acer rubrum L.) and 

dogwood (Cornus florida L.). Basal area averaged -- ---- 87 square feet per acre in 125 trees >5.0 inches 

d.b.h., mean stand diameter was 11.3 inches; however, diameter ranged uo to 33 inches. The dominant stand age averaged 85 years. 

A commercial timber harvest removed about 

two-thirds of the stand basal area. The residual 

stand contained 24 square Feet of basal area oer 

acre in 12 trees with mean diameter of 19.0 inches 

d.b.h. Species composition das almost exclusively 

northern red oak. Of 63 trezs in the residual 

stand, there were 2 yellow-pnnlar and 2 black oak. 

The 59 northern red oak made up 94 percent of 

Lf Paper presented at the Fourth Biennial stand basal area. 

Southern Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. After the harvest cut, all residual understorv 

trees were injected or basal sprayed with 2,4,5-T 

2' Principal Silviculturist , Southeastern in fuel oil. The follnwinp season the area was 

Forest Experiment Station, U.S. Department of mist blown with 2,4,5-T to eliminate as much of the 

Agriculture, Forest Service, Asheville, NC 28804. ground cover as possible, with the idea of establishing red oak seedlines from the residual oak 

stand. 
RESULTS 

Residual Stand Growth 

Growth of the residual stand from 1965 to 1985 

is summarized in table I. 

Table 1.--Twenty-year change in the residual overstory of a twa-aged Southern Appalachian hardwood 

stand 

Board 

Basal - foot Clear 

Year area D volume leng* 

2 Et /acre Inches Ebmlacre Feet 

Diff . 17.4 6.0 4,426 4-1.8 

Annual 

growth 0.9 0.3 22 1 

The residual trees responded well to the unlimited growing space. Even the seemingly sparse 

stocking gave annual board-foot volume growth of 

221 board feet per acre, which was about 60 percent of what might have been expected from a fully 

stocked stand (Schnur 1937). 

Diameter Growth Response 

The residual trees immediately responded positively to the increased growing space despite 

their advanced age. Increment cores pulled 12 

years after release were used to compare prerelease 

and postrelease growth ratios (fig. I). A comparison with comparable trees in an adjacent untreated 

stand was also made. 

treated 

0 untreated 

-5 -4 -3-2 -1 1 2 3 4 5 

YEARS BEFORE AND AFTER HARVEST 

Figure 1 .--Diameter growth of treated residual 

stand compared with untreated stand before and 

after treatment. 

Post treatment grow-tti in the shelterwood was 

about double pretreatment growrh after 4 years. 

Growth rate then declined to about 58 percent 

greater than bath pretreatment and growth in the 

adjacent untreated stand. One could speculate that 

the develi,ping second storb- began to compete more 

strongly for the resources of the site after 4 or 

5 gears, 

Bole Quality 

Bole quality was apparently little affected 

by the rather drastic release of the residual trees. 

Average clear length at time of release was about 

29.6 feet. Twenty years later, clear length 

averaged 31.4 feet--an inconsequential change. 

Some epicormic sprouts were initiated but were later 

shaded out by the developing understory trees. 

Regenerat ion 

Distribution of regeneration by species and 

size class at stand age 20 is shown in table 2. 

It is quite evident that the regeneration stand is 

being dominated by yellow-poplar and red maple. 

Sweet birch (Betula lenta L.) is still a factor at 

age 20 but is rapidly falling behind. Other desirable species such as the oaks, hickory (Carya 

spp.), ash (Fraxinus spp.), etc., are still present 

but their numbers and particularly their size distribution indicate they will not be a significant 

part of the future stand. Miscellaneous understory 

species--mainly dogwood--are present in large numbers but are mostly small and not a serious threat 

in stand development at this point. Basal area in 

the regeneration portion of the stand for stems 

>l.0 inch d,b.h, averaged 70 square feet per acre. 

ConsTderinp onlv the 100 largest stems per 

acre that are expected to form the bulk of the next 

stand, 6Q percent are yellow-noplar. The effort to 

encourage the establishment and growth of northern 

red oak was not successful. The few new seedlings 

established were not able to compete with other 

species (Loftis 1983a). 

Comparison to Clearcut 

Regeneration in the developing two-aged stand 

is quite similar to that in an adjacent clearcut 

of the same age. In terms of species composition 

both are dominated by yellow-poplar with red maple 

and sweet birch being prominent members (t,-ii-Je 3). 

The major difference is in the amount nf locust 

(Robinia -- spp.) present. This can nrobably be attributed to the herhici.de treatment in the sl~rlterwood. Althouoh tile herbicide was ineffectilre on 

species like red maple, it did hill most of the 

locust. Number of stems >1.0 inch d.b.h. is about 

the same in botli stands. However, stems in the 

clearcut are larger, averaging 3.1 inches as 

opposed to 2.9 inches, Considering only the 100 

largest stems per acre, the shelterwood averaged 

7.3 inches and 54 feet tall. Comparable stems in 

the cleareut were 23 percent larger in diameter 

and I1 percent taller, at 8.9 inches and 60 feet 

tall. 
Table 2.--Distribution of regeneration in a two-aged Southern Appalachian hardwood stand at age 20 

Diameter class (inches) 

Species 1 2 3 4 5 6 7 8 9 10 11 12 Total 

Ye3 low-poplar 147 156 56 36 31 17 11 6 8 -- R 6 48% 

Oaks 3 - - -- -- -- - - - - - - -- - - - - - - 3 

Birch 3 6 4 7 47 11 11 14 -- -- - - - - -- - - 166 

Locust 8 2 2 3 1 3 -- 3 -- - - -- -- - - -- 6 7 

Red maple 106 8 9 56 19 19 11 3 3 -- 3 -- -- 309 

Misc. I1 b 32 3 89 11 8 3 6 -- 3 -- -- - - -- 443 

a Timber species. 

Nontimber species, e.g., dogwood. 

Table 3.--Comparison of regeneration of Southern 

Appalachian hardwoods by irregular shelterwood 

method and clearcut at age 20 

- 

Stems per acre = ~5.0 inches d.b.h. 

Species Shelterwood Clearcu~ 

Yell ow-poplar 8 7 9 3 

Oaks 0 11 

Sweet birch 2 5 2 1 

Locust 3 6 0 

Red maple 20 3 3 

Misc. I~ 0 11 

Misc. I1 b - 3 - 4 

138 2 33 

- - 

a Timber species. 

Nontimber species, e. g., dogwood. 

DISCUSSION AKD CONCLUSIOE 

To be successful, a system for creating and 

maintaining two-aged stands must meet at least two 

criteria. It must provide conditions under which 

regeneration can become established, grow, and 

mature. It must be possible for the residual older 

age class to grow for extended periods under very 

open stand conditions without excessive loss 

through windthrow, other mortality, and degrade. 

In this instance the residual northern red 

oaks, although relatively advanced in age, responded well. Basal area increased by 73 percent 

and board-foot volume by 84 percent in the 20-year 

period. The annual board-foot growth rate of 221 

board feet per acre was about 62 percent of what 

might be expected for a fully stocked stand on a 

comparable site. Bole quality was apparently unimpaired by the development of branches on the 

lower bole. Clear length changed little over the 

20-year period. Other studies of development in 

sparse stands suggest that the rapid development of 

second story of trees serves to maintain clear 

length by shading out any epicormic sprouts that 

develop on the lower bole (Beck 1981). Of course, 

some species such as white oak (2. alba I,.) are 

more prone to sprout and may not be as desirable 

for this type of management. 

Development of the reproduction into a second 

age class is progressing well in this case. Sufficient stems of desirable species are present to 

develop a fully stocked stand that can be carried 

to rotation. Species composition is quite similar 

to an adjacent stand created by clearcutting. Sapling development has been slowed somewhat by the 

older age class but not markedly so. 

This study, along with our experience from 

several other studies, provides some guidelines for 

creating and maintaining two-aged stands. First, a 

low residual density is necessary to promote satisfactory development of the second age class so that 

it can form an integral part of the future overstory. 

Residual densities in the range of 20 to 30 square 

feet of basal area per acre seem appropriate. In 

this case, 25 square feet of basal area per acre 

was concentrated in a few large stems (mean d.b.h. = 

19.0). In another study (Beck 1981), a residual 

stand of 26 square feet of basal area was left in 

71 trees per acre (mean d.b.h. = 8.2 inches). The 

second age class that developed had become an integral part of the main canopy after 25 years--contributinp about one-third of the stand with 
two-thirds formed by residuals. Other studies demonstrate the need for a low residual basal area. 

In a series of shelterwood cuts with residual 

basal area from 40 to 70 square feet per acre, 

basal area growth rates were 2 to 3 feet per year 

(Loftis 1983b). These stands closed quickly, within 10 to 15 years. In fact, Dale (1972) has shown 

that maximum board-foot growth rates may be obtained 

for upland oak stands with stocking as low as 40 

square feet on average or better sites. Under such 

circumstances the stands close quickly and a second 

age class of relatively intolerant species is unable 

to develop . 

As is the case with any type of regeneration 

method, treatment of the tolerant understory species 

is a necessity. Selective treatment with herbicides 

to prevent sprouting of undesirables would be the 

preferred method. 

Although it is possible to create and maintain 

two-aged stands, the esthetic desirability remains 

to be evaluated. The regeneration process involves 

a fairly drastic treatment--one that creates a much 

stronger visual impact than single tree selection, 

which may have been envisioned. If the aim is to 

keep an oak component continuously on the site, 

then special measures to ensure the presence of 

large advance oak reproduction at the time of the 

regeneration cut, as suggested by Loftis (1983a) , will be necessary. This would entail a treatment 

of the toierant understory and Pight shelterwood 

cut perhaps 10 to 15 years prior to the main 

harvest cut. 

LITERATURE CITED 

Beck, Donald E. Evaluating a diameter-limit cut in 

Southern Appalachian hardwood through stem analysis. In: Barnett, James P., ed. Proceedings of the 

1st biennial southern silvicultural research conference; 1980 November 6-7; Atlanta, GA. Gen. 

Tech. Rep. SO-34. New Orleans, LA: U.S. Department 

of Agriculture, Forest Service, Southern Forest 

Experiment Station; 1981:164-168. 

Dale, Martin E. Growth and yield predictions for 

upland oak stands: 10 years after initial thinning. Res. Pap. NE-241. Broomall, PA: U.S. Department of Agriculture, Forest Service, Northeastern 

Forest Experiment Station; 1972. 21 pp. 

Della-Bianca, Lino; Beck, Donald E. Selection management in Southern Appalachian hardwoods. Southern 

Journal of Applied Forestry 9(3) : 191-196; 1985. 

Loftis, David L. Regenerating Southern Appalachian 

mixed hardwood stands with the shelterwood 

method. Southern Journal of Applied Forestry 

7(4):212-217; 1983b. 

Olson, David F., Jr. Site index curves for upland 

oak in the Southeast. Res. Notes 125. Asheville, 

NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station; 

1959. 2pp. 

Schnur, G. Luther. Yield, stand, and volume tables 

for even-aged upland oak forests. Tech. Bull. 

560. Washington, DC: U.S. Department of Agriculture; 1937. 87 pp. 

Smith, David M. The practice of silviculture. 8th 

ed. New York: John kTiiey & Sons; 1986. 527 pp. 

Troup, R. S. Silvicultural systems. 3rd ed. rev. 

London: Oxford University Press; 1955. 216 pp. 

Loftis, David L, Regenerating red oak on productive 

sites in the Southern Appalachians: a research 

approach. In: Jones, Earle P., Jr., ed. Proceedings 

of the 2d biennial southern silvicultural research 

conference; 1982 November 4-5; Atlanta, GA. Gen. 

Tech. Rep. SE-24. Asheville, NC: U.S. Department 

of Agriculture, Forest Service, Southeastern Forest 

Experiment Station; 1983a:144-150. 
DEVES0P;"IENT OF AZ)VAEiCED OAK RE-ENERATION 

1 i AS LNnUENCED BY RmOV& OF MIDSTORY AND UNDERSTORY VEGETATIOE2" G, 6, Janzen and J, D, Bodgee' 

Abstract.--bre-hamest release of advanced oak stems by either removal of 

unwanted vegetation or removal of unwanted vegetation plus cutting desirable 

sterns to the ground was compared. A£ ter three years, there was no statistical 

difference between treatments in post-treatment height growth for oak stems. 

However, third-year results indicate that respome to release is delayed. At 

that time, the mean height of oak stems which were cut to the ground surpassed 

the man pre-treatment height and the growth rate was significantly greater 

than that of the controls or the uncut but released sterns. Also, oak stems 

which were released but not cut to the ground showed an increasing rate of 

height growth in the third year. Height growth of oak regeneration in the 

control plots was very low in all three years. 

INTRODUCTION 

Natural regeneration of hardwood stands is 

most of ten accomplished by cmmrrrcial 

clearcutting and bringing the residual stems 

back to the ground (KelZison et al, 1981). 

Reproduction of hardwood species comes from one 

of three sources--s tump sprouts, seedling 

sprouts, or true seedlings which are stems 

which germinate shortly before or after the 

stand is cut (Beck 1983). Young seedlings are 

an important source of regeneration only for 

the ligh t-seeded, f as t-growing species such as 

yellow-poplar (Liriodendron tulipifera L.) 

which are able to compete with sprouts or stems 

left after the clearcut. Young oak seedlings, 

which are the most commercially desirable 

species, grow too slow initially to compete 

with sprouts and other vegetation common in 

clearcut s. If desirable advanced reproduct ion 

of an adequate size and number is not present 

before the stand is harvested, it is doubtful 

that the next stand will contain species that 

are best suited for wood production (Sander 

1972, Loftis 1982, Plarquis 1982, Johnson and 

Shrop shire 1983) . 

Several systems have been developed for 

evaluating the regeneration potential of 

hardwood stands (Sander et al. 1976, Johnson 

1980, Harquis and Bjorkhom 1982), Regeneration 

potential is based on the size and nmber of 

desirable stems of advanced regeneration 

L'paper presented at Southern 

Silvicultural Research Conf ereace, Atlanta, 

Georgia, November 4-6, 1986. 

'The authors are research technician and 

professor, Department of Forestry, Mississippi 

Agricultural and Forestry Experiment Station, 

Mississippi State University. Contribution No, 

6527 of the Mississippi Agr iculturkl and 

Forestry Experiment Station. 

present inmediately be£ ore the stand is 

harvested and the sprouting potential of the 

severed trees. For southern hardwoods, stems 

of advanced regeneration which are greater than 

one foot tall and severed trees less than ten 

inches diameter at breast height (dbh) are 

given the highest values, 

Since hardwood mnagers must depend so 

heavily on advanced regeneration, a major 

question confronting them is how long the 

regeneration can be maintained in the 

understory. Johnson (1975) found that new 

Nut taL L oak (Quercus nut tal lii Palmer) 

seedlings remain in the understory for five to 

ten years. Any practice which would allow 

sunlight to reach these seedlings will probably 

improve their chances of survival and their 

growth. EicGee (1968) found that height and 

leaf growthoof Northern Red oak (Quercus rubra 

L.) decreased as the amount of light reaching 

the seed lings decreased, 

When oak stems in the understory are 

plentiful but small, some form of partial cut 

may enable them to grow to a size large enough 

to be effective for regeneration (Sander 1972, 

Hurst and Myers 1982). Reduction of the 

overstory may accomplish this purpose in some 

cases, but most often it is the presence of 

shade-t olerant species in the mid- and lower 

canopies rather than rhe overstoq that 

restricts light to the forest floor (Johnson 

and Krinard 1976, McKnight and Johnson 1980, 

Rellison et aL, 1980). If desirable stems in 

the understory or ground flora are to benefit 

from sunlight passing through the overs tory 

then this undesirab re midstory and understory 

vegetation should be control led (Johnson and 

Jacobs 1981, Loftis 1982). Undesirable stems 

should be killed in order to reduce sprouting 

and provide more growing space for the 

development of desirable stems (Graney and 

Rogerson 1985, Loftis 1985). Tlne objective of 

this study was to determine if advanced oak 

regeneration could be maintained and its 
Table 1 .--Number of stems per acre, basal area, and man dbh of trees greater than 1.0 inch 

dbh before treatments were installed (lowerstory, midstory, and overstory trees). 

Number of Stew Basal Area ~DBH 

Inject/ Inject/ Inject/ 

Inject Cut Control Inject Cut Control Inject Cut Control 

------- No./acre------- ------- ftL/aci<e------- ----------in.--------- 

Red oak&/ 9 5 95 185 66.0 36.5 32.8 7.6 4.6 4.1 

White 2 / Oaks- 18 23 4 8 16.8 30.7 21.2 12.3 - 14.6 6.5 

Desirable Speci 

Other than Oaks- " 135 130 125 13.7 11.0 11.8 3.1 3.0 3.0 

Undesirable species/ 377 330 337 28.2 37.1 50.1 2.6 3.1 3.4 

Total 

L/Red Oaks: Cherrybark, water, and willow oak 

'White Oaks: Post, swamp chestnut, and white oak 

)jDesirable species other than oaks: Green ash and sweetgum 

I~ndesirable species: Blackgum, deciduous holly, elm, hawthorn, hickory, ironwood, 

re$ maple, and red mulberry 

growth enhanced prior to final harvest through 

control of undesirable midstory and understory 

vege tat ion. 

METHODS 

The stand used for this study was located 

within the floodplain of Loakfoma Creek on the 

Noxubee National Wildlife Refuge in Winston 

County, Mississippi. This stand contained 

adequate advanced oak regeneration with water 

(Quercus nigra L .) and willow oak (Quercus 

phellos L.) being the primary oak species. The 

overstory was composed of mainly water oak, 

willow oak, and hickory (Carya species) while 

the mids tory consisted of hickory and other 

less desirable, shade-tolerant species. 

Sweetgum (Liquidambar s tyracif lua L. ) and green 

ash (Fraxinus pennsylvanica Marsh.) as well as 

many undesirable spe cies were present in the 

lower story with the oaks (Table 1). Age of 

the overstory at the time the study was 

installed was 100 years. Site index (base age 

of 50 years) for water and willow oak is 100 

feet (Baker and Broadfoot 1979). 

Nine 115-acre plots were installed with 

six plots randomly selected for treatment of 

mid- and uncle rs tory vege tation. Control plo ts 

were located apart from the treatment plots so 

as to avoid any edge effects. Treatments were 

assigned as follows : 

(1) Inject only. All trees greater than 

1.0 inc dbh that were undesirable 

species- 9/ and did not contain at 

least one number three factory grade 

sawlog (USDA Forest Service 1981) 

were injected with glyposate. 

Desirable stems were left intact. 

(2) Inject/Cut, InjectlCut plots 

combined injection as above plus 

cutting of the remaining stems to the 

ground. Undesirable stems too small 

to be injected but three feet in 

height or taller were cut and stump 

sprayed with glyphosate. Desirable 

stems that did not contain at least 

one number three factory grade sawlog 

were cut to determine if a more 

vigorous sprout could be obtained. 

(3) Control. Control plots received no 

herbicidal treatment; midstory and 

understory remained intact . 

?/A11 oaks, sweetgum, green ash, and 

yellow-poplar were classed as desirable species 

for the purpose of this study. All other 

species were classed as less desirable due to 

their low cmmrcial value or because they were 

of f-site. 
Injection and cutting plus stump spraying of 

undesirable stems was done in the fall of 1983. 

Cutting of desirable stems was done in the 

winter of 1983-84. 

Each major plot contained two 1/100-acre 

circular subplots which were used to monitor 

changes in the number of stems of advanced 

regeneration. Growth response of individual 

oaks was measured on £if teen randomly located 

oaks within each major plot, These trees served 

as 'center of a 112-meter radius subplot in which 

all trees were flagged and measured for height 

by species. 

RESULTS AND DISCUSSION 

Pre-treatment Measurements and Observations 

A diameter-limit cut, which occurred about 

1945, left many of the overstory stems which are 

present today. As a result of this 

high-grading, stems are generally of poor 

quality. The resultant overstory has many holes 

in the main canopy, thus allowing substantial 

sunlight to pass through. Domination of the 

understory by shade-tolerant species was just 

beginning to occur when plots were selected. 

back to the ground. Also, undesirable stems 

less than 1.0 inch dbh and taller than 3 feet 

in the inject/cut plots were cut and stump 

sprayed. Some resprouting of undesirable 

stems occurred in the inject and injectfcut 

plots. 

No statistical difference was found for 

the number of advanced oak stems present 

before treatments were installed (Table 3). 

Mater and willow oak were the main oak 

species, with some cherrybark (Quercus falcata 

var, pagodifolia Ell.), swamp chestnut 

(Quercus michauxii Nut t .) , and white oak 

(Quercus alba L.) also present. Most of these 

oaks were seedling-s ized stems of various 

ages. Control plots had significantly more 

advanced stems of desirable species other than 

oaks present before treatments were installed. 

Species other than oak that were classed as 

desirable were green ash, sweetgum, and 

yellow-poplar. The majority of the desirable 

stems, other than oak, found initially in the 

control plots were sweetgum seedlings which 

germinated in 1983. The total number of 

advanced undesirable stems present before 

treatments were installed was high for all 

plots. 

Most of the undesirable stems greater than 

1.0 inch dbh were removed by i~jection in the 

treated plots (Table 2). InjectICut plots also 

had the other desirable and oak species brought 

Table 2.--Number of stems per acre, basal area, and mean dbh of trees greater than 1.0 inch 

dbh after treatments were installed (lowerstory, midstory, and overstory trees). 

Number of Stems Basal Area ~DBH 

Inject/ Inject/ Inject/ 

Inject Cut Control Inject Cut Control Inject Cut Control 

1 I Red Oaks- 9 5 15 185 66.0 34.2 32.8 7.6 20.0 4.1 

White 2 1 Oaks- 18 18 48 16.8 28.9 21.2 12.3 16.8 6.5 

Desirable Speci 

Other than Oaks- " 135 3 125 13.7 3.3 11.8 3 13.6 3.0 

Undesirable Species- 41 5 10 337 5.3 12.1 50.1 13.9 14.8 3.4 

Total 253 46 695 101.8 78.5 115.9 5.6 17.2 3.7 

ljRed Oaks: Cherrybark, water, and willow oak 

Zj~ite Oaks: Post, swamp chestnut, and white oak 

2'~esirable species other than oaks: Green ash and sweetgum 

/~ndesirable species : Blackgum, deciduous holly, elm, hawthorn, hickory, ironwood, 

red maple, and red mulberry 
Table 3.--Total number of advanced stems per acre and mean height of stems before 

treatments were installed. 

- 

1 1 OaksDesirable Specie 

Other than Oaks- / Undesirable Species- 31 

- 

No. /Acre x Ht . NO. /Acre x Ht . No. /Acre Ht. 

Inject 5,700 a- 41 48.5 417 b 187.0 4,017 a 80.3 

Control 6,200 a 31.3 4,517 a 91.3 4,283 a 73.2 

VOaks: Cherrybark, swamp chestnut, water, white, and willow oak 

Z'Desirable Species Other than Oaks: Green ash, sweetgum, and yellow-poplar 

'Undesirable Species: Beauty berry, black cherry, blackgum, box elder, deciduous holly, devil's walking stick, dogwood, elderberry, elm, hawthorn, hickory, 

honey locust, ironwood, loblolly pine, persimmon, red maple, red twlberry, sugarberry, and tree sparkleberry 

b/Values that are followed by the same letter indicate no statistical difference at the .05 level 

Pos t-t reatment Measurements and Observations 

Effects on seedling stocking 

The total number of oaks per acre 

decreased in all treatments (Tables 3 and 4). 

Although oaks and desirable species other than 

oaks were not intentionally sprayed with 

herbicides, some herbicide damage may have 

occurred in the injectlcut plots. Most of the 

seedling loss in all plots was due to the 

mortality of very small or very young 

seedlings. The product ion of viable acorns was 

low in the years following treatment of the 

plots; so the establishment of new oak 

seedlings was low. Thus, most of the oak stems 

in all plots were stems that were present 

before treatments were initiated. 

For the first three year period of this 

study, mortality of oak seedlings was no higher 

in the control plots than in the treatment 

plots. However, as noted below, growth, 

especially in the third year, was lower in the 

control plots and it is expected that mortality 

will increase in those plots in the future. As 

indicated above, past cutting practices left 

this stand in a fairly open condition, which 

probably accounts for the amount of 

regeneration present. Had there been less 

light at the forest floor it is doubtful if 

seedling survival would have been so good. 

The number of stems of desirable species 

other than oak increased in the inject and 

injectlcut plots. Most of this increase was a 

result of sweetgum germination in the second 

and third years after treatments were 

Installed. After three years, stems of 

desirable species other than oaks had decreased 

by about one-half in the control plots. This 

decrease was caused primarily by mortality of 

many of the sweetgum seedlings which were less 

than a year old at the time the study was 

instal led. 

There was a slight increase in the number 

of undesirable stems in the treated plots. 

This was largely the result of new germination, 

but resprouting of some of the herbicide 

treated stems occurred also. The large 

increase in number of undesirable stems in the 

control plots was mainly the result of 

establishment of hickory seedlings in the 

second year following treatment. 

Effects on Seedling Growth 

After three years, there was no 

statistical difference in height growth of oak 

stems in the different treatments (Table 5). 

Analysis of height growth for all species was 

based on those seedlings which remained alive 

and showed no significant die-back during the 

three year post treatment period. Although 

there was no statistical difference in the mean 

height growth after three years, oak stems in 

the injectlcut plots showed the largest 

increase. These stems had already grown back 

to a height taller than before treatment. Oak 

seedlings in the inject plots showed dieback in 

the first year after treatment and a slight 

increase in height in the second year. It was 

not until the third year following treatments 

that oaks in the inject plots showed any 

appreciable gain in height. There was little 
Table 4. Total number of advanced stems per acre three years after 

treatments were installed. 

l, Desirable Speci 

Treatment 3 1 Oaks- Other than Oaks7 Undesirable SpeciesInject 4 1 4,900 a- 1,480 a 4,550 a 

Control 5,330 a 2,830 a 7,480 a 

I/0aks: Cherrybark, swamp chestnut, water, white, and willow oak 

/Desirable species other than oaks: Green ash, sweetgum, and 

ye1 low-pop lar 

2'~ndesirable species : ~eauty berry, black cherry, blackgum, box 

elder, deciduous holly, devil's walking stick, dogwood, elderberry, 

elm, hawthorn, hickory, honey locust, ironwood, loblolly pine, persimmon, red maple, red mulberry, sugarberry, and tree sparkleberry 

/Values that are followed by the same letter indicate no stafistical difference at the .05 level. 

Table 5.--Mean height and height growth of advanced stems af ter treatments 

vere installed. 

Oaks 

Treatmentl' 1984 1985 1986 1983-84 1983-85 1983-86 1985-86 

------ HT (cm)------ ------------ x 3/ HT Growth (cm)---------- 

Inject 48.2 48.9 51.7 -0.3 a- 4/ 0.4 a 3.2 a 2.8 b 

Control 32.0 32.2 33.0 0.7 a 0.9 a 1.8 a 0.9 b 

Desirable Speci f7 Other Than OaksCont rol 106.7 108.7 112.1 15.4 a 17.3 a 20.8 a 3.5 b 

L'~aks: Cherrybark, water, and willow oak 

Z'IIesirable species other than oaks: Green ash and sweetgum 

/Trees which were listed as dead in any year were not included in the 

analysis of height growth. 

'Values that are followed by the same letter indicate no statistical 

difference at the .05 level. 
growth of oak stems in the control plots in the 

three years following treatment. 

Height growth of stems of other desirable 

species followed essentially the same pattern 

as described above for oaks. Fastest growth 

was from sprouts in the injectfcut plots, but 

even after three years average height was less 

than before treatment. This difference may be 

partially explained by the fact that the stems 

of these species were much taller when they 

were cut than were the oaks. Desirable stems 

other than oak showed a slight increase in 

height growth in the inject plots. While some 

of the sweetgum stems found in the control 

plots exhibited some height growth, many of 

these stems had died by the third year after 

treatment. Most of the growth of desirable 

stems other than oaks in the control plots was 

by green ash stems. Many of the green ash 

stems in the control plots were taller than 

other stems in the understory. 

CONCLUSION 

Based on the preliminary results of this 

study the following tentative conclusions can 

be drawn: 

1. Removal of midstory and understory 

competition appears to be a feasible 

way to mint ain advanced r e g e n e r a t i o n 

of desirable species, especially 

oaks, and to promote their growth 

prior to the final harvest cut. 

2. Response of suppressed oaks and other 

desirable species to release may be 

slow. The indications are that at 

least three years will be required 

for a significant response. 

3. After removal of undesirable midstory 

and unde rs tory stems, best 

development of suppressed desirable 

seed lings may be obtained by severing 

them near ground line. The resultant 

sprouts are very vigorous and grow 

much faster than uncut st ems. 

Pre-cut heights are surpassed within 

three years. Also, the quality of 

the sprouts may be superior to that 

of uncut stems which tend to be 

flat-topped, crooked, or have 

multiple leaders. 

LITERATURE CI TED 

Baker, J. B., and W. M. Broadfoot. 

1979. A practical field method of site 

site evaluation for cominercially important 

southern hardwoods. USDA Forest Serv. 

Gen. Tech. Rep. SO-26. 51 p. 

Beck, D. E. 

1983. Planned hardwood regeneration. 

Forest Farmer 43 (1) : 18-19. 

Beltz, R. C., and R. L. Johnson. 

1984. Mid-south hardwood resources. Proc. 

Proc, of the 14th Annual Southern Forest 

Economics Workshop. Memphis, Tn. $far ch 

13-15, 1984. p. 1-5. 

Graney, D. L., and T. L. Rogerson. 

1985. Growth of oak, ash, and cherry reproduction following thinning of upland 

hardwood stands in the Boston Mountains of 

Arkansas. Proc. of Fifth Central Hardwood 

Forest Conf . Urbana-Champaign, 11. April 

15-17, 1985. p. 4-10. 

Hurs t, G. A*, and R, C. Myers. 

1982. Regeneration following a commercial 

improvement cut in a bottomland hardwood 

forest. Hiss. Agric. and Forestry Exp. 

Sta. Research Rep. Vol. 7, No. 18. 4 p. 

Johnson, P. S., and R. D. Jacobs. 

1981. Northern red oak regeneration after 

preherbicided clearcutting and shelterwood 

removal cutting. USDA Forest Serv. Res. 

Paper NC-202. 5 p. 

Johnson, R. L. 

1975. Natural regeneration and development 

of Nuttall oak and associated species. 

USDA Forest Serv. Res. Paper SO-104. 12 

P 

Johnson, R. L. 

1980. New ideas about regeneration of hardwoods. Prsc . of Hardwood Regeneration 

Symposium. Jan. .29, 1980. Atlanta, Ga . p. 17-19. 

Johnson, R. L., and R. M. Krinard. 

1976. Hardwood regeneration after seed tree 

cutting. USDA Forest Serv. Res. Paper 

SO-123. 7 p. 

Johnson, R. L., and F. W. Shropshire. 

1983. Bottomland hardwoods. In: Silvicultural Systems for the MajorForest Types 

of the United States. Russell M. Burns, 

Tech. Compiler. USDA Agric. Handb. 445. 

p. 175-179. 

Kellison, R. C., D. J. Frederick, and W. E. 

Gardner . 1981. A guide for regenerating and managing 

natural stands of southern hardwoods, 

North Carolina Agric. Res. Serv. Bull. 

463. 24 p. 

Loftis, D. L. 

1982. Regenerating red oak on productive 

sites in the southern Appalachians: a 

research approach. Proc. of the Second 

Biennial South. Silv. Res. Conf. Nov., 

1982. Atlanta, Ga. p. 144-150. 

Loftis, D. L. 

1985. Preharvest herbicide treatment improves regeneration in southern 

Appalachian hardwoods. S. Jour. of App. 

For. 9(3) : 191-196. 
Marquis, D. A. 

1982. Effect of advance seedling size and 

vigor on survival after clearcutting. 

USDA Forest Serv, Res. Paper NE-498. 7 p. 

Marquis, D. A*, and J. C. Bjorkbom. 

1982. Guidelines for evaluating regeneration before and af ter clearcutting 

Allegheny hardwoods, USDA Forest Serv. 

Res, Note HE-307. 4 p. 

McGee, C. E. 

1968. Northern red oak seedling growth 

varies by light intensity and seed source. 

USDA Forest Serv. Res. Note SE-90. 4 p. 

McKnight, J. S., and R. L, Johnson. 

1980. Hardwood management in southern bo ttomlands. Forest Farmer 39:31-39. 

Sander, I. L. 

1972. Size of oak advance reproduction: 

key to growth following harvest cutting. 

USDA Forest Serv, Re=. Paper MC-79. 6 p, 

Sander, I. L., P. S. Johnson, and R. F. Watt. 

1976. A guide for evaluating the adequacy of 

oak advance reproduction. USDA Forest 

Serv. Gen. Tech. Report NC-23. 7 p. 

Sternitzke, H. S. 

1973. Eastern hardwood resources: trends 

and prospects. Forest Products Jour. 

24:3, 13-16. 

USDA Forest Service. 

1981. Grading hardwood logs for standard 

lumber. USDA Forest Serv., Forest Prod. 

Lab. Formerly Pub. No. D1737-A. 19 p. 
RESPONSE OF A SECOND-GROWTH NATURAL STAND 

2 1 J. R. Toliver, S. G. Dicke, and R. S. PrengerAbstract.--The effect of crown thinning on natural 

second-growth baldcypress [Taxodium distichum (L.) Rich] trees 

was studied to determine responses as measured by growth in 

height, diameter, and volume three years after thinning. 

Twelve, lf4-acre circular plots were established in a 

63-year-old baldcypress-water tupelo (Nyssa aquatica L.) stand 

inside the Atchafalaya Basin near Bayou Pigeon, LA. Treatments 

consisted of thinning to approximately 180 sq ft, 140 sq ft, and 

100 sq ft of basal area per acre and no thinning (control = 222 

sq ft). Diameter and volume growth of individual trees 

increased as thinning intensity was increased, but height growth 

was not influenced. Total volume growth on a per acre basis was 

not significantly different among treatments. However, at the 

highest intensities of thinning (100 and 140 sq ft) this growth 

was distributed on fewer and larger trees. The data indicate 

that thinning second-growth baldcypress trees will increase 

growth and quality of the larger more valuable trees. 

INTRODUCTION 

Baldcypress has been a commercially 

important tree in the South since colonial 

times. In the early 1900ts, vast stands of 

virgin baldcypress formed the backbone of 

Louisiana's lumber industry and allowed her to 

lead the nation in cypress lumber production 

from 1900-1920 (Burns, 1980). By 1925, the 

majority of the virgin baldcypress had been 

cut and 10 years later the supply was virtually 

exhausted. A USDA forest survey estimate 

indicated that by 1934, 1.6 million acres of 

baldcypress had been cutover (Norgress, 1947). 

Current production in the United States is 

less than 200 million bd ft per year Williston 

et al., 1980). However, the total volume of 

standing cypress, primarily second-growth, is 

impressive. According to Williston et al. 

(1980), growing stock on commercial forest land 

in the U.S. totals approximately 5.5 billion cu 

ft. About 19.8 billion bd ft of sawtimber is 

available, of which 36 percent is in trees 17 

inches dbh or larger. Louisiana and Florida 

I/ Paper presented at Fourth Biennial 

southern Silvicultural Conference, Atlanta, GA, 

Nov. 4-6, 1986. 

2f Associate Professor, Instructor, and 

for& Research Assistant, respectively, School 

of Forestry, Wildlife, and Fisheries, Louisiana 

Agricultural Experiment Station, LSU 

Agricultural Center, Baton Rouge, LA 70803, 

contain more than half of this volume. Data 

obtained in a USFS inventory (Rosson and 

Bertelson, 1986) indicate 5.2 billion bd ft of 

cypress sawlog growing stock in Louisiana. 

Eighty-three percent of this growing stock is in 

the South Delta Louisiana Parishes of which 70 

percent of the trees are less than 11 inches 

dbh. Thus, in Louisiana numerous densely 

stocked stands exist and appear to be in need of 

thinning. It is not uncommon for these natural 

stands of 60 to 70-year-old cypress to have 

500-700 trees per acre, 200-300 sq ft of basal 

area per acre and average 7-8 inches in diameter 

at 18 inches above butt-swell. 

Quite often the merchantable trees are cut 

by diameter-limit cutting practices (12 to 

16-inch minimum) resulting in high-grading 

whereby numerous smaller and poorer quality 

trees are left standing. Few, if any, stands 

are properly managed. 

Very little research has been accomplished 

in second-growth baldcypress stands and 

knowledge of optimum silvicultural practices is 

limited, For example, will these densely 

stocked stands respond to release by thinning 

and, if so, what is the proper stocking and 

density to maximize growth of high-quality 

cypress trees? Therefore, the objective of this 

study was to investigate the magnitude in growth 

of 63-year-old baldcypress trees when thinned to 

three Levels of stand basal area per acre. 
METHODS AND PROCEDrnES 

Description of the Study Area 

A natural stand of baldcypresslwater tupelo 

was selected within the Atchafalaya Basin near 

Bayou Pigeon in iberville Parish, Louisiana. 

The area consists of level clayey soils of the 

Fausse series that are characteristic of the 

backswmps and depressions within the Basin 

floodway. These soils are high in fertility and 

generally contain adequate amounts of moisture 

throughout the year. The site is subject to 

prolonged flooding one or more times each year, 

generally during the months of December through 

July but is not under constant water (Prenger, 

1985). 

Estimated virgin timber volume in 1908 was 

approximately 5553 bd ft per acre of which 86 

percent was baldcypress and the remaining water 

tupelo. These volumes were rather low for 

virgin baldcypress stands and indicate that the 

trees were probably growing in isolated patches. 

The timber was logged and skidded by pull-boat 

from 1909-1914 (~ile information, Williams, 

Inc., Patterson, LA, present owners). 

The stand is assumed to have originated as 

a result of seed-fall from the virgin trees. 

Annual ring counts taken in 1980 from 14 

dominant and codominant trees indicated the mean 

age of the stand to be 63 years, which indicates 

the stand originated shortly after the virgin 

timber was harvested. 

Initial Measurements and Study Design 

The study was initiated in the fall of 

1980. Twelve 114-acre circular plots were 

randomly established in the stand. A 118-acre 

measurement plot was established within each 

major plot. All trees in the measurement plots 

were numbered with an aluminum tag nailed 

approximately 18 in. above butt swell (normal 

diameter). 

Original measurements taken on the trees 

were diameter (inches) at the nail and total 

height (feet). Crown class (dominant, 

codominant, intermediate, and suppressed) was 

determined for each tree according to Smith, 

1962. This informaticn was used to determine 

the basal area and number of trees for each of 

the 12 plots. Then the plots were assigned to 

blocks according to their similarity in total 

basal area. This was done to insure that each 

thinning treatment could be randomly assigned 

within a low 6188-206 sq ft/a), mid (207-222 sq 

ft/a) and high (246-259 sq ft/a) basal-area 

block. 

One of four th4nning treatments was 

randomly applied to a plot with a block. 

Treatments consisted of thinning to basal areas 

of approximately 180 sq ft/a, 140 sq ft/a, 100 

sq ft/a and no thinning (control, 220 sq ft/a). 

Trees were marked to be cut or left based on 

species and potential for high quality sawtimber 

if left for at least 15-20 years. A crown 

thinning, crop-tree approach, was performed in 

December, 1980. High quality cypress trees were 

favored and surrounding trees were removed. 

Trees were first removed from the general level 

of the crown canopy and then down into lower 

crown classes until the desired basal area was 

achieved. Cutting was performed with chainsaws 

and the cut trees were left laying on the 

ground. 

Measurements and Calculations 3 Years 

After Thinning 

Measurements were taken in the fall of 

1983, three growing seasons after the thinnings 

were completed. Total height and normal 

diameter of the trees was measured. Height and 

diameter growth of each tree was calculated for 

the three-year period of growth. 

Individual tree cubic foot volumes, inside 

bark, were calculated before and after thinning 

treatments were applied. Volumes were generated 

by using the following cypress volume equation: 

Volume = .0036 x D 1.74618 H1.07498 where 

= diameter 18 inches above butt swell (inches), 

H = total height (feet), Parresol (1983). 

Analysis of variance were calculated with 

Statistical Analysis System (sAS) procedure GLM 

and the DUNCAN option (sAS Institute, Inc. 

1982). 

RESULTS AND DISCUSSION 

Initial Stand Characteristics 

The second-growth stand was found to be 

densely stocked with an average of 604 trees per 

acre. Baldcypress made up 83 percent of the 

stand by stems, basal area, and volume per acre, 

and water tupelo constituted the remaining trees 

ba able 1). It is interesting to note that the 

virgin stand included approximately the same 

ratio by volume in 1908 (86% cypress to 14X 

tupelo). 

Table 1. Characteristics of a natural 

second-growth stand of baldcypress/water 

tupelo in the South Delta region of 

Louisiana. 

Trees/ Normal Basal 

Species acre dim. Ht. area Vol. 

3 in. ft. ft2/a ft /a 

Cypress 50 1 i*7 63 180 6507 

Tupelo 103 8.4 62 42 1332 

All trees 604 7.8 63 222 7839 

The diameter distribution, similar to a 

normal bell-shaped curve, was indicative of an 

even-aged stand. Over 50 percent of the trees 
were cypress, less than 9.0 inches in diameter, 

and classified in the intermediate and 

suppressed crown class categories (Table 2). 

However, 31 percent of the stand was made up of 

codominant and dominant cypress trees (1881acre) 

ranging from 10-15 inches in diameter. These 

larger cypress trees averaged 11.0 inches in 

diameter and 79 feet tall and provided the basis 

for the crown thinning able 2). 

Table 2. Mean density, diameter, and height, by 

crown class of a second-growth stand of 

baldcypress/water tupelo in the South Delta 

region of Louisiana. 

Crown Density Diameter Height 

class (treeslacre) ( inches) (feet) 

Dominant 14 1 12.0 14.6 80 73 

Co -Dom. 174 39 10.0 10.0 78 68 

Intermed. 101 32 7.4 8.2 65 66 

Suppressed 212 31 5.6 6.2 48 49 

Stand Characteristics After Thinning 

Due to the nature of the stand and the 

thinning method applied much of the cutting was 

done within the condominant and intermediate 

cypress crown classes. As thinning intensity 

was increased more of the lower crown class 

trees were eliminated including many suppressed. 

Water tupelo was cut to favor cypress thus it 

became a small component on the plots 

particularly at the 140 and 100 basal area 

thinning intensities (Table 3). After thinning, 

mean total plot basal area per acre was 221, 

179, 142, and 101 sq ftla for the four 

treatments and cypress made up 83, 84, 94, and 

93 percent of the basal area respectively. Due 

to the major interest in producing high quality 

baldcypress sawlogs and the low component of 

water tupelo left after thinning, only the 

growth response of cypress will be addressed in 

this paper. 

Three-year Growth Response of Baldcypress 

Height Growth 

No significant differences in mean height 

growth were found among treatments or among 

crown classes. In fact height growth averaged 

less than 1 foot. It appears that height growth 

was not stimulated by thinning and the stand 

height is increasing at a very slow rate. 

Williston et al., 1980 refer to a 41-year-old 

cypress plantation in Tishomingo County, Miss. 

in which the dominants averaged 69 feet tall and 

to a thinned cypress stand near Abbeville, Miss. 

in which the crop trees averaged 119 feet tall 

at roughly 100 years of age. The average height 

of the dominant and codominant trees in this 

study was 79 feet at 66 years. Assuming the 

sites are comparable the trees in this study 

have not reached their maximm height thus the 

potential for increased height growth is 

present. 

Table 3. Mean numbers of trees left after 

thinning a second-growth stand of baldcypresslwater tupelo to various intensities 

of basal area. 

Thinning intensity (balacre) 

Control 

( 220 180 140 100 

Crown 

class Cyp Tup Cyp Tup Cyp Tup Gyp Tup 

- - - - - - treeslacre - - - - - - 

Dom . 5 0 5 0 11 029 0 

Go-dom. 189 16 128 27 144 13 93 3 

Interm. 83 45 77 19 80 5 19 6 

Supr. 229 67 197 27 83 40 51 29 

TOTAL 506 118 407 73 318 58 192 38 

An underlying objective of this study was to 

determine if the remaining suppressed, 

intermediates, and weaker codominants would 

respond to thinning. If these lower crown 

classes would respond then the stand could be 

managed as a two storied stand. The larger 

trees could be harvested and the second story 

could be nurtured into merchantable sawlog 

trees. Height growth would be important in 

recovering the vigor of the lower crown class 

trees. However, the 3-year data indicates very 

little if any response in height growth of the 

trees. On the other hand 3 years is probably 

not enough time to expect much of a response. 

Individual Tree Diameter and Volume Growth 

In general diameter growth increased with 

an increase in thinning intensity (Table 4). 

With the exception of the codominants those 

trees on plots thinned to 100 basal area more 

than doubled their diameter growth over the 

unthinned trees. Diameter growth of the 

codominants in the 100 basal area plots was 

one-third greater than in the control. It is 

interesting to note that the suppressed and 

intermediate trees on the 100 basal area thinned 

plots grew at approximately the same rate as the 

dominants and codominants on the unthinned 

plots. Although there was very little 

difference in diameter growth among thinning 

treatments within a given crown class, thinning 

alone significantly increased diameter growth 

over the control (unthinned). The lack of 

significant differences among thinning 

treatments within a crown class may be related 

to the method of thinning. The best trees were 

always chosen and the adjacent competition was 

removed. However, we expect the trees in the 

lower basal area plots to sustain their improved 

growth over a longer period of time whereas the 
crowns of the trees on the 180 basal area plots 

will close quicker and diameter growth will 

decrease. Thus given more time the difference 

in diameter growth among treatments will 

probably become more prominent. 

Table 4. Mean diameter growth of 65-year-old 

baldcypress trees 3-years after thinning. 

Thinning intensity (balacre) 

Crown Control 

Class (220) 180 140 100 

- - - Dia. growth (inch) - - - 

Dominants .30a .50a .58a .60a 

Codominants .26b .39a .35ab .42a 

Intermediates .09a .05a .13a .23a 

Suppressed .02b .08b .06b .26a 

Mean .13c .18bc .23b .39a 

'~eans followed by the same letter within rows 

are not significantly different (P 0.05) 

according to Duncan's New Multiple Range Test. 

Volume growth per tree followed the same 

trend as diameter growth. Mean volume growth 

for individual trees was 0.48, 0.65, 0.85, and 

1.44 cubic feet respectively for the Control, 

180, 140, and 100 basal area thinning 

intensities. There were no significant 

differences among thinning treatments within crown classes. However, as thinning intensity 

increased there was a pattern of increased 

volume growth within all crown classes. 

Stand Growth 

When individual tree volume growths were expanded to stand volume growth on a per acre 

basis no significant differences were found 

among the four thinning treatments. Cubic foot 

volume growth per acre was 241, 255, 265 and 265 

for the control, 180, 140 and 100 basal area 

thinnings. However, the growth was distributed 

on fewer and larger trees on the lower basal 

area plots. Thus, these trees should become 

larger and higher quality merchantable trees in 

less time. Stand characteristics 3 years after 

thinning are presented in Table 5. 

CONCLUSIONS 

Second-growth baldcypress trees responded 

to crown thinning sat age 63 years. Three years 

after thinning, individual tree diameter and 

volume growth had increased with increases in 

thinning intensity; however, there was no change 

in height. Although not statistically 

significant, there was a trend of increased 

diameter and volume growth among thinning 

treatments within each of four crown classes. 

Total volume growth over 3 years was not 

significantly different among thinning 

intensities. However, the volume growth was 

concentrated on fewer and larger trees on the more intensely thinned plots. 

Table 5. Characteristics of a second-growth 

bafdcypress/water tupelo stand 3 years after 

thinning to various intensities of basal area 

per acre. 

Thinning Basal Volume Trees/ 

intensity area acre 

220 (control) 189 7111 501 

180 156 5573 394 

140 138 5141 322 

100 9 8 3693 184 

LITERATURE CITED 

Burns, A. C. 1980. Frank B. Williams, cypress 

lumber king. J. For. Hist. 24(3):127-134. 

Norgress, R. E. 1947. The history of the 

cypress lumber industry in Louisiana. The 

La. Historical Q, 30(3):46-61. 

Parresol, B. R. 1983. A volume and taper 

prediction system for baldcypress in 

Louisiana. M.S. Thesis. La. State Univ., 

Baton Rouge. 134 p. 

Prenger, R. S., Jr. 1985. Response of a second-growth natural stand of baldcypress 

trees [Taxodium distichum (L.) Rich.] to 

various intensities of thinning. M.S. 

Thesis. La. State Univ., Baton Rouge. 52 

P + 

Rosson, J. F., Jr. and D. F. Bertelson. 1986. 

Forest statistics for South Delta Louisiana 

parishes. South. For. Exp. St. , USDA For. 

Serv. Resource Bull. SO-106, 31 p. 

SAS Institute Inc. SAS User's Guide: 

Statistics, 1982 Edition. Cary, NC: SAS 

Institute Inc., 1982. 584 p. 

Smith, D. M. 1962. The practice of 

silviculture, 7th ed. John Wiley & Sons, 

New York. 578 p. 

Williston, H. L., F. W. Shropshire, and W. E. 

Balmer. 1980. Cypress management: a 

forgotten opportunity. Southeastern Area 

State and Private For., USDA For. Serv. 

For. Rep. SA-FR8, 8 p. 
A COTJIPmISON OF BIOMASS AND NUTRIENT CONTEm 

M. A. Megalos, D. J. Frederick . Clark 111 

and D. R. Phillips- ZP 

Abstract,--Biomass and nutrient content (N, P, K, Ca and Mg) were examined in fully-stocked, even-aged I@-, 20, 40- and 

60-year-old Piedmont and Coastal Plain bottomland hardwood 

stands. Aboveground biomass yields for the Coastal Plain 

sites were approximately double the Piedmont biomass values 

for the 1Q- and 20-year-old stands. Nutrient content was directly related to biomass yield and thus was greater for 

all Coastal Plain bottomland sites except the 40-year-old 

stands, Annual biomass accumulation for the 60-year-old 

stands did not differ significantly between provinces; h w- ever, N and P accumulation rates were 8.1 anf 1.i kg ha-'yr-' 

for the Coastal Plain and 6.9 and 8.8 kg ha' yr' for the 

Piedmont sites, respectively. The high nutrient accumulation 

rates of Coastal Plain bottomland hardwood stands indicate 

that greater nutrient removals and possible productivity 

declines may occur following intensive harvesting, 

I NTRODUCT ION 

The Piedmont and Coastal Plain are two major 

provinces supporting hardwood forests in the 

southeastern United States. The southern Piedmont 

encompasses nearly 18 million ha within Virginia, 

North Carolina, South Carolina and Georgia. 

Roughly 64 percent of the total land area is 

commercial forest supporting over 1.27 billion 

tonnes of hardwood standing biomass (Bechtold and 

Phillips, 1983). piedmont forests are a diverse 

mixture of hardwood species and mixed pine types 

occupying a spectrum of sites from dry upland 

slopes and ridges to rich bottomlands. 

Bottomland hardwood forests are the most 

productive in the United States and cover an estimated 12.9 million ha on the Atlantic and Gulf 

Coastal Plains with Virginia, North Carolina, 

South Carolina, Georgia and Florida comprising 42 

percent of the total (bngdon and others, 1981). 

These Coastal Plain forests are also a diverse 

mixture of hardwoods and hardwood-conifer associations that occur on the floodplains of major 

rivers originating in the Mountains, Piedmont and 

Coastal Plain. Sites typically have little topography and soils range from poor to well drained 

and from loam to silt loam in texture. 

1/paper presented at the Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, GA, 

November 4-6, 1986, 

Z/~espectivel~ Research Assistant and Professor, 

3chool of Forest Resources, North Carolina State 

University and Research Scientist and Project 

"?aderr United Sta~es Forest Service, Southeastern 

Forest Experiment Station. 

Piedmont and Coastal Plain hardwood forests 

are typically -poorly stocked , are low in quality, 

and contain small diameter trees reflecting a history of high grading, agricultural use, fire 

and grazing (Smith and Linnartz, 1980; Kellison 

and others, 1981). Difficulties associated with 

managing mixed stands and poor market conditions 

for low quality trees have discouragd intensive 

management. Only recently has the potential of 

these forests ken realized with the technological 

advances in harvesting and utilization systems 

and, new products made using hardwood fiber. 

An increasing number of hardwood stands are 

being harvested and a larger portion of the trees are king utilized, Topwod, branches, small 

twigs and even leaves are often removed during 

whole tree harvesting (WH) Leaving behind very 

little residue. whole tree harvesting of hardwood 

stands can increase utilization over 100 percent 

compared to conventional saw log harvesting 

(Phillips and Van kar, 1984), However, because 

of the disproportionately high nutrient concentrations in topwood, small branches and foliage, 

large amounts of nutrients can be removed from the 

site (Francis, 1984; Messina and others, 1983; 

Megalos and others, 19861, Johnson and others 

(1982) stated that losses of ?j, P, K, and Ca after 

WTH were 2.9, 3,l 3-3 and 2.5 times more than 

those in saw Log harvesting of a mixed hardwood 

stand. Utlimately, the amount of nutrients 

removed following intensive utilization will 

depend on the total Siomass, the nutrient concentrations sf the various tree eornLmnents, and total 

nutrient content of the trejl, 

We undertciok this study to eompcare the bio- mass and nutrient content of stands and species 

growing on Piedmont and Coastal Plain 'aottomlands 

and to determine whether differences existed among 
age classes and across regions. 

MATERIALS METHO% 

Sixteen mixed, even-aged, fully stocked 

Piedmont a& Coastal Plain hardwood stands in the 

10, 26, 46 and 60-year-age classes on the bottomland site type were located, Stands were well 

distributed over each province and located on industrial, state, and private forestland in cooperation with members of the N, C, State Hardwood 

Research Cooperative. Vegetation was sampled in 

late summer or early fall to minimize the variation in moisture content and nutrient concentrat ions which can vary seasonally (Auchmoody and 

Grewling, 1979; Bowersox and Ward, 1977). Two 

replications of concentric sample plots were established around a randomly located plot center 

in each stand. Pulpwood and sawtimber trees (12.7 

cm BH) were destructively sampled on a 0.04-ha 

plot and saplings (2.5 - 12.4 cm EM) were sampled 

on a 0,008 ha concentric circular subplot. Green 

weight of stems, branches and foliage was determined for all trees. Dry weight determinations 

were made using stem disks, branch disks and 

foliage subsamples following the methodology of 

E'rederick and others (1979). Disk and foliage 

subsamples were selected for nutrient analysis 

from a minimum of three trees per 2-5 cm diameter 

class per species on each plot. Tree components (bole, branches, foliage, wood and bark) were 

systematically subsampled following procedures 

developed bj Messina and others (1983). 

Trees, shrubs and vines > 1 m tall and < 2.5 

cm DBH were sampled on four randomly located 1-67 

x 4.98 m subplots, one per quadrant as determined 

by random azimuths from plot center. 

Understory vegetation ((1 m tall) was sampled on two randomly established transect lines 

consisting of twenty-five, 30.5 x 61.0 cm subplots 

spaced at 1 m intervals along each line originating from plot center. Composited samples were subsampled for biomass and nutrient analyses, 

Laboratory Procedures 

Laboratory analyses followed standard procedures, with all tissue samples dried to a constant 

weight at 70 degrees C. Samples were ground in a Wiley mill to pass through a 0.85 mm mesh stainldss steel screen. Total nitrogen [N), phosphorus 

(P), potassium (K), calcium (Ca) and magnesium 

(Mg) were determined following a modified wetashing procedure (Parkinson and Allen, 1975). 

Nitrogen and P were determined by automated colorimetric methods on a Technicon Autohalyzer as the 

ammonium sal icy la te and phosphomolybdenum complexes, respectively. Potassium, Ca and Mg were determined by atomic absorption spectrophotometry. Samples were analyzed in the soils 

laboratory of the Deparment of Forestry at North 

Carolina State University, 

dominant species on the bottomland site type in 

both provinces (Figure 1). Sweetgum comprised 

approximately 60 percent of the overstory campsition. Additional dominant species occurring on the Coastal Plain in descending order of occur- rence included cot tonwood (COT1 (Populus del toides 

L,), red maple (RM) (Acer rubrum L,) and white oak 

(WO) (Querms alba L). Additional Piedmont species in descendinq order of occurrence included: 

water oak (WAO) (~uercus nigra L), hickory (HK) 

(Carya spp,) and green ash (GA) (Fraxinus 

nnsylvanica Marsh.), Other species, ind ividglly mmprisinq less than 3 percent of the total 

freqkncy accoubted for about 16 percent of the 

total species occurrence in both provinces. 

Percent 

Coastal Plain Piedmont 

Species Frequency Distribution 

Figure 1, Overstory species composition of 

Coastal Plain and Piedmont bottomland hardwood 

stands. (Sweetgum, SG; Cottonwood, COT; red 

maple, RM; White Oak, WO; water oak, WAO; hickory, 

HK; green ash, GA) 

Aboveground Biomass 

Total aboveground biomass yields for Coastal 

plain 10 and 20 year-old stands were 45.8 and 

142.1 Mq ha-' respectively at similar ages (Table 

1) Piedmont forty year yields (255.7 Mg ha-') were significantly higher than Coastal Plain 

(217.3 Mg ha-') and not significantly different 

for both provinces in the 60-year age class 

(Figure 2.). 

The exceptional yields for the 40-year-old 

Piedmont stands and decline at age 60 reflect a likely growth peak and optimal rotation age for 

biomass production close to age 40. The data for 

the Coastal Plain is less conclusive but suggests 

a longer rotation age, perhaps 60 years or more. 

Coastal plain stands of all ages had a larger 

sapling component which accounted for some of the 

differences in total aboveground biomass. Understory vegetation biomass was a minor component 

except in the 1Q-year old Piedmont hardwood 

stands, 

RESULTS AND DISCUSSION 

Nutrient Concentration of Tree Cwnponents 

Species Composition 

Sweetgum (Liquidambar styraciflua L) was the 

The concentration of nutrients (N, PI K, Ca 

and Mg) in tree components in bottomland stands of 
Table 1, Dry weight biomassofcomponents, understory vegetation and total trees of Piedmont and Coastal 

Plain bttomlad hardwocd stands in the Southeastern United States. 

Total 

we Foliage Branches Bole Sap1 ings Understory Aboveground 

Piedmont 

- - 15.6 

22.6 32.6 18.0 

73.6 171.0 5.3 

82.6 154.8 3.5 

-- Coastal Plain 

mi Coastal Plain 

Figure 2, Total aboveground dry biomass for 

Coastal Plain and Piedmont hardwood stands 

both provinces was generally greatest in foliage 

and decreased in the order foliage > stem bark > 

branches > stemwood. (Megalos and others, 1986; 

Phillips, 1985; and Messina, 1983) (Table 2). 

Nutrient content is a function of the amount of 

biomass and its distribution among these components. At early stand ages a greater proportion 

of biomass is contained in nutrient-rich foliage 

and branches. As a stand develops, the bole com- ponent beco.nes the largest biomass source and 

ultimately comprises the largest aboveground 

nutrient peol. 

mtrient Content of Stands 

Nutrient :ontent of bottomland stands was directly related to biomass yield (Table If. The 

10- and 20-year-old Coastal Plain stands contained 

approximately twic2 the N, P, K, Ca and Mg Levels 

of similar aged Piedmont stands (Table 2). At age 

40, Piedmont bottomland total biomass yields were 

nearly 18% greater than comparable Coastal Plain 

stands, yet nutrient contents were disproportionately lower for the elements N, P, K and Mg. 

Nitrogen, P, K and Mg levels for the 40-year-old 

Piedmont stands averaged only 2.5% greater than 

Coastal Plain nutrient values, Calcium was the 

only nutrient that exhibited a direct relationship 

with biomass yields across both geographic re- gions. At age 60, there were large differences in 

nutrient content which reflected proportionate 

differences in nutrient concentrations. 

The Coastal plain bottomland yield (238 Mg 

ha-') was 3 percent lo er than that of the -Y Piedmont (244.3 Mg ha ) (Table 1). However, this 

represented greater nutrient content levels for 

the Coastal Plain of 15 percent for N, 40 percent 

for P, 23 percent for K, 34 percent for Mg and 

decrease of 5 percent for Ca. The average nutrient concentrations for the Coastal Plain were much 

greater than those of similar aged Piedmont stands 

with the single exception of Ca. 

Coastal Plain foliage and sapling dryweight 

values for 60 year-old stands were 2 and 4 times 

greater, respectively, than Piedmont foliage and 

saplings yields. 

The relative abundance and nutrient 

"richness" of f 01 iage and juvenile sapling 

material in the Coastal Plain stands comprise a significant portion of the total nutrient content 

of the stand and partially explains the large 

difference in nutrient contents between provinces. 

Annual Accumulation and Elemental Utilization 

Although this study represents a "point in 

time" view of nutrient content and biomass yield 

of bottomland stands, the comparisc~ of nutrient 

accumulation rates between provinces can provide 

insight into the relative efficiency of biomass 

production, Annual biomass accmulation rates for 
Table 2, Nutrient content of Pi t and Coastal plain hardwood stands in the Southeastern United States. 

Understory Total 

Foliage Branches ~ofe-I Sap1 ings Vegetation Abovegr ound 

Nitrogen - 

18 

17 8 

166 

Phosphorus - 

2 

28 

19 

Potassiun 

- 

17 

18 7 

165 

Calcium - 

64 

4 13 

597 

Magnes im 

- 

6 

53 

47 

-- Coastal Plain 

Nitrogen - 

79 

160 

186 

Phosphorus 

- 

12 

29 

22 

Potassium 

- 

96 

16 8 

232 

Calcium - 

17 0 

261 

734 

Magnesium 

1/10 an diameter-outsidebark. 
both province averaged 4.0 Mg ha-' yr-l, however, 

N a P accmulation rates were 8,l and 1.1 kg ha 

yrIrf or the Coastal Plain and 

yr for the Piedmont sites, re relatively small differences in nutrient accumulation rates could result in the increased uptake of 

72 kg of N and 19 kg of P in Coastal Plain stands over a 60 year rotation comp~lred to Piedmont 

stands with comparable yields, The increased 

uptake of nutrients in Coastal Plain bttornland 

stands should be of particular interst to forest 

managers and researchers concerned with nutrient 

removals following intensified harvesting, Higher 

stand nutrient content may suggest increased sus- ceptibility to productivity declines following 

intensive harvesting, 

When evaluating the nutrient content and 

biomass of various stands it is important to have a common method of comparison, This study used 

the efficiency ratio concept from ecological 

studies and applied it to nutrient utilization. 

Nutrient utilization is defined as the ratio of 

nut ient content per dry weight of biomass kg 5 Mg' . Listed below are data from our 60-year-old 

bottomland stands and a loblolly pine stand for 

baseline comparison (Table 3). 

Table 3. Nutrient utilization efficiency rates 

for various stand types in the southern 

United States, 

Stand Type 

Nutrient 

N P 

--------- K-Mg 

Kg Mg-1--------- 

Coastal Pla 

Bottomland - l7 2.0 0.3 1.8 5.4 0.5 

Piedmont 

Bottomland L/ 1.7 0.2 1.4 4.8 0.4 

LQbloj $Y Pine - 1.1 0.1 0.9 2.1 0.3 

1/ tkssina, 1983 

Z/ Megalos, 1986 

:/ Cole and Rapp, 1981 

Both bottomland hardwood stands rank well above 

the nutrient efficiency of loblolly pine, for all 

nutrient elements with P and Ca showing the 

greatest differences. 

CONC WS IONS 

Southeastern bottomland forests are very 

productive and complex ecosys tems. Many variables 

including site, species mix, stand structure, age 

and other factors will influence biomass and 

nutrient accumulation and distribution. Based on 

these data, Coastal Plain and Piedmont bottomland 

stands show many similarities in these parameters 

but also disparities which could have very 

impr tant implications to management. The differences in nutrient contenr, -1stribution and utilization efficiency with these two stand types 

deserve recognition and further elucidation if 

these forests are to be managd most effectively. 

LITEtUlTtiRE CITED 

Auchmoody, L R. and T. Grewling, Problems 

associated with chemical estimates of bimass 

In: Impact of Intensive Harvesting on Forest 

Igutrient Cycling, SUW college of 

Enviromntal Science and Forestry, Syracuse, 

NY. August 13-16, 1979, 421 pp. 

~echtold, W. A, and D. R. Phillips. The hardwood resource on non-industr ial private forest land 

in the Southeastern Piedmont. USDA. Forest 

Service Research Paper. SE-236, 1983. 19 pp, 

Bowersox, T. W, and W. W. Ward. Seasonal 

variation in foliar nutrient concentrations in 

black cherry. Forest Science 23:429-432. 

1977. 

Cole, D. W. and M. Rapp. Elemntal cycling in 

forest ecoysystans, In: D. E. Reichle (4,). 

Oynamic Properties of Forest Ecosystems. 

~nternational Biological Program 23. Cambridge 

University Press, Malta 1981. pp. 341-409, 

Francis, John K. Yield and nutrient removal by 

whole-tree harvest of a young bottomland 

hardwood stand. USDA Forest Service Research 

Note SO-305, 1984. 4 pp. 

Frederick, D. J., W. E. Gardner, A. Clark, 111, 

D. R. Phillips and M. Williford. Biomass, 

nutrient and energy estimation of mixed 

southern hardwoods using an area sampling 

technique. In: IrJ. E. Frayer (ed.) 

Proceedings Forest Resource Inventory, Vol. 

11. Colorado State University, Fort Collins. 

1979. p~. 782-789. 

Johnson, D. PI., D. C. West, D. E. Todd and L, K. 

Mann, Effects of saw log vs, whole-tree 

harvesting on the nitrogen, phosphorus, 

potassim and calckm budgets of an upland 

mixed oak forest. Soil Science Society of 

American Journal. 46:1304-1309. 1982. 

Kellison, R, C., D. J. ~rederick and W, E, Gardner 

A guide for regenerating and managing natural 

stands of southern hardwoods. North Carolina 

Agriculture Ex,wriment Station Bulletin #463. 

N. C. State University, Raleigh. 1981. 24 pp. 

Langdon, 0. G., J. P. NcClure, D. D. Hook, J. M, 

Crockett, and R. Hunt. Extent, condition, 

managenent, and research needs of bottomland 

hardwood-cypress forests in the Southeast. In: 

J. R. Clark and J. Benforado (eds.) Wetlands 

of ~ottomland Hardwood Forests. Elsevier 

Scientific Publishing Co., New York. 1981. 

pp. 71-85. 
Megalos, M. A. Nutrient content and distribution 

in natural Southern Piedmont hardwoods. 

Master's Thesis. North Carolina State 

University, Raleigh, 1986, 78 pp. 

Megalos, M. A,, D. J, Frederick, A. Clark, 111 and 

D, R, Phillips, Biomass, nutrient and energy 

content of southern Piedmont har 

North Carolina State University, Hardwood 

Research Cooperative Series No. 5, Raleigh, K, 

1986. 34 pp. 

Messina, M. G. Nutrient content and distribution 

in natural southern coastal plain hardwoods, 

WI,D. Dissertation North Carolina State 

University, Raleigh, NC, 1983, 57 pp, 

mssina, M. G,, R. Ballard, D. J, Frederick and A, 

Clark 111. A test of single disk estimation 

of hardwood branch and bole nutrient 

concentration. Forest Science 29:618-626, 

1983. 

Parkinson, J, A. and S, E, Allen. A wet oxidation 

procedure suitable for the determination of 

nitrogen and mineral nutrients in biologic 

materials. Cmunication Soil Science Plant 

Analysis. 6(1):1-11. 1975, 

Phillips, Ch R. Nutrient contents of hardwood 

trees on wetland sites in the southeastern 

Coastal Plain. Ph.D. Dissertation, Clgnson 

University, Clemson. 1985, 80 pp. 

Phillips, D. R. and D. H, Van War. Biomass 

removal and nutrient drain as affected by 

total-tree harvest in Southern pine and 

hardwood stands. Journal of Forestry 

82:547-550. 1984, 

Smith, D. W, and N. E. Linnartz. The southern 

hardwood regions. In: J, W. Barnett (ed,), 

Regional Silviculture of the United States. 

2nd. W., Wiley & Sons, MI. 1980. 551 pp. 
SWAMP WHITE OAK RESPONSE TO VARIOUS LEVELS OF 

NITROGEN AND PHOSPHOR~JS - SURFACE APPLIED" 

(ABSTRACT) 

John R. Seifert and Phil E. pope2 

In 1985, ten levels of nitrogen with and without phosphorus was surface applied to two year old swamp white oak seed1 ings. Nitrogen (as 

ammonium nitrate) was applied at rates from 0 to 200 lbs per acre and 

phosphorus at the rate of 90 lbs per acre was applied to three nitrogen 

treatments. Chemical weed control was applied in the spring of each 

year. Soil analysis was performed in 1985 before and after treatment 

and leaf tissue analysis was performed after treatment in 1985. Soil 

and leaf analysis was again performed in 1986 to evaluate second years 

effects. Results will include diameter growth, height and increment 

growth, soil nutrients and leaf tissue. 

1 Paper presented at Fourth Bi enni a1 Southern 

Si 1 vicul tural Research Conference, At1 anta, Georgia, 

November 4-6, 1986. 

'~e~artrnent of Forestry and Rat ural Resources, 

Purdue Oniversi ty , West Lafayette, IN 
THE EFFECT OF THINNING AND PRUNING ON THE GROWTH 

1 / OF PLANTED LOBLOLLY PINE STMDS - 

2 1 Daniel J. Leduc and Boris Zeide - 

Abstract.--A study was begun in 1971 to determine the 

effects of four levels of thinning (initially 40, 60, 80, 

and 100 and subsequently 30, 50, 70, and 90 square feet 

of basal area per acre) and three levels of pruning 

(live crowns equal to 25, 40, and 55 percent of total tree 

height) on the growth of a plantation of loblolly pine (Pinus 

taeda L.). In 1984 the sixth measurement of this stand was 

completed and the data was analyzed for the effects of 

thinning, pruning, blocking, and treatment-blocking 

interaction. These factors had no effect on height growth. 

Diameter growth increased with decreasing density and 

increasing live crown ratio, and in general, the accumulated 

cubic foot volume (present volume at the latest measurement 

plus all previously removed volumes) and maximum mean annual 

increment increased with both density and crown ratio. 

INTRODUCTION 

To maximize the productivity of intensively 

managed southern pine forests, they have to be 

maintained at optimal density and pruning levels 

until the age when the maximum mean annual 

increment of desired products is reached. The 

search for these optimal levels, particularly 

that of density, has been a major aspiration of 

foresters, empirically pursued since the 

inception of this profession. The first solution 

which was found was that productivity increases 

with the number of trees and reaches a maximum in 

undisturbed stands with the greatest possible 

tree number and complete crown closure. This 

answer emerged over 200 years ago in Denmark 

(Mar:Moller 1954) from a comparison of overcut 

and high-graded forests with closed and 

productive ones. However, during the nineteenth 

.jipaper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

2i~orestry Research Specialist and Prcfessor 

of Forestry, respectively, University of 

Arkansas, Monticello, AR 71655. 

century a reversal of this result was 

proposed. It was felt that within reasonable 

limits, volume increment (of stems) was 

considered to be approximately proportional to 

the degree of thinning, that is, to the 

decrease in tree number. The contradiction 

between these two answers is not as sharp as 

it seems since the new concept was not 

developed in high-graded stands. Rather, it 

came from long-term observations of more or 

less evenly spaced best (crop) trees, selected 

at an earlier age and relieved from excessive 

competition stress during subsequent 

development by frequent thinning of 

neighboring trees. The most authoritative 

support of the concept came from Schwappach 

(1911) who, based on the results of 30 years 

of observations on 40 permanent sample plots 

established in Prussian beech stands, showed 

that heavy thinning increased the volume 

increment up to 16 percent. 

The next development can be attributed to 

Wiedemann (1932), Schwappach's successor in 

charge of the Prussian Forest Experiment 

Station. Using 50-year observations of the 

same beech and other stands, he demonstrated 

that, within a wide range of density, 

productivity is independent of thinning 

intensity (and tree number). These results 
have been confirmed in many countries 

(Mar:Moller 1954, Tkachenko 1955, Georgievsky 

1957, Wiedemann 1960, Carbonnier 1976, Daniel 

and others 1979, Drew and Flewelling 1979), and 

at present the majority of foresters believe 

that thinning can redistribute the increment 

from smaller to larger stems but not increase 

its amount. This opinion is not a consensus 

(Assmann 1970), and considerable effort, in the 

form of thinning studies, is presently directed 

toward the empirical search for optimal density 

(Clutter and athers 1983). 

The only reliable way to find the best levels 

of density and pruning and the age of their 

maximum mean annual increment are long-term 

observations of permanent plots thinned to 

various density levels. Such studies are a 

standard method of growth research, 

particularly in productive loblolly pine 

forests (Williston and Dickerson 1968, Van 

Hooser 1970, Burton 1981, Clason and Cao 1985). 

One such study was established 16 years ago 

in a 12-year old loblolly pine (Pinus taeda L.) 

plantation situated four miles southeast of the 

University of Arkansas at Monticello. This 

work was done by James D. Burton of the 

Southern Forest Experiment Station and 

described in Study Plan 1107-1.21 (Burton 1968) 

and Establishment Report FS-SO-1115-4.2 (Burton 

1971). The original design included four 

levels af thinning (initially 40, 60, 80, and 

100 and subsequently 30, 50, 70, and 90 square 

feet per acre) and three levels of pruning 

(live crown lengths equal to 25, 40 and 55 

percent of total height), Each combination had 

three replications, Four additional plots were 

established as check plots where one of the 

four thinning treatments was applied without 

pruning. The total number of plots was 40. 

Each plot had a gross size of 132 X 132 feet. 

The measurement plot, 66 X 66 feet, lay in the 

center of the gross plot. Thus each study plot 

consisted of a 0.1 acre measurement plot 

surrounded by an isolation zone one chain wide. 

Since 1981 the study has been maintained by 

the Department of Forest Resources of the 

University of Arkansas at Nonticello in 

cooperation with the Forest Service and the 

Georgia-Pacific Corporation. The present study 

plan (Zeide 1981) is a continuation of the 

previous work and is intended to maintain the 

plots and carry out periodic measurements of 

the plots. 

There were a few changes in the study plan 

since it was originally conceived. In 1981, 

after consultation with the Forest Service, 

pruning, which actually had not been done since 

1974, was formally deleted from the study plan. 

It was felt that pruning had only a restricted 

practical application because of its prohibitive 

cost (Zeide 1981). In 1984 five control plots 

were established in the adjacent untreated part 

of the same plantation as the original 40 

treated plots. At the same time, stem analysis 

was done using 25 of the trees to be removed 

by the 1985 thinning, These trees were 

selected to represent all four thinning levels 

and the control plots as they existed at age 

27. 

METHODS 

Inventory methods 

The same basic inventory methods were used 

for all of the six measurements of the study 

area. The diameters of all trees located in 

the buffer strip were taken to calculate basal 

area. The actual study plot trees were 

measured for diameter, height to the first 

live branch, total height, and the height to 

each 2-inch diameter class outside bark (so 

that volume could be calculated by the height 

accumulation method developed by Grosenbaugh 

(1954)). Additionally, the inventory in 1984 

included the measurement of crown radius in 

the longest direction and 90 degrees to it, 

and the diameters at one and three feet above 

the ground. Diameter at breast height (the 

paint mark set by previous inventories rather 

than an actual 4.5 feet from tree base) was 

measured with a diameter tape to the nearest 

0.1 inches, crown width was measured with a 

tape measure, and the diameters at one and 

three feet above the ground were measured with 

calipers. 

All height measurements were taken with a 

Zeiss teledendrometer because this is both an 

accurate instrument and the same instrument 

used in all previous inventories. To achieve 

measurement consistency, we used the procedure 

described by the Forest Service technician who 

worked on all previous inventories. 

Measurement accuracy was improved by 

calibrating the dendrometer for instrument 

bias in 1984 and applying the correction to 

the recorded data. 

Selection of trees to .be thinned 

Size and form of trees were the chief 

criteria used to select trees for removal. 

Bent trees and trees with cankers or broken 

tops were always selected against when there 

was sufficient basal area to permit their 

removal. However, even low quality trees were 

not removed when the basal area did not meet 

the study guidelines. 

Methods of data treatment 

Volume calculation 

Height accumulation was used to calculate 

the volume of all sampled study plot trees. A 

discussion of the theory and general 

application of this technique is provided by 

Grosenbaugh (1954), Lohrey and Dell (1969), 

and Lohrey (1973). While the details of this 

method will not be explained, some background 

on our particular application of it is necessary. 
With the technique of height accamulation, 

volume is calculated as a linear function of 

height, the sum of the heights to each 

successive two inch taper step, and the 

accumulation of the previous sum to the upper 

two inch taper step. The form of this 

function is shown by: 

where : 

VOLUME is volume in any selected units; A,B, 

and C are calculated coefficients; L is the 

sum of section lengths or tree height; W is 

the sum of the heights to the top of each 

section; and H' is the sum of the sum of the 

heights to each section. 

The coefficients used in this calculation 

are determined from geometric formulae and are 

based on the volume units, the size of the 

taper step, and the ratio of the diameter 

inside bark (dib) to diameter outside bark 

(dob) when inside bark volume is desired. For 

the purposes of this paper a dibldob ratio of 

1.0 was used since the volume of interest was 

total outside bark volume in cubic feet. The 

coefficients of equation 1 for this ratio are 

as follows: A = 0.0436, B = 0.0000, and C = 

0.0073. In addition to these coefficients, 

HTACCU, the FORTRAN program used to calculate 

volume, allows a minimum DBH and top diameter 

to be entered for each volume calculated. To 

obtain total cubic foot volume outside bark, 

zeros were entered for each of these 

variables. 

During the last two measurements for which 

we were responsible, all study plot trees were 

measured with sufficient detail to calculate 

volume. However, the previous four inventories 

of this study obtained detailed information 

for only 12 trees per plot. For the remaining 

trees only the diameters were recorded. In 

order to provide a comprehensive volume growth 

summary, an equation which would allow us to 

predict volume from known data was needed. 

For this purpose several functions for 

calculating volume based upon diameter and 

other stand conditions were investigated. A 

simple log-linear model was settled on because 

of the apparent goodness-of-fit of this model, 

and the multicollinearity problems which 

developed in the more complex models. 

Multicollinearity causes parameter estimates 

to be unstable and to have high standard 

errors (SAS Institute, 1982). Explicitly, the 

model used was: 

where : 

A and B are coefficients calculated for each 

type of stem volume and age; and Ln is the 

natural logarithm function. 

Since logarithmic transformation introduces 

bias when the original dependent variable is 

not lognormally distributed, an adjustment 

factor was calculated for each equation by 

finding the average ratio of actual to 

predicted volume. This factor was used to 

adjust all predicted volumes. The equation 

coefficients, adjustment factors, and other 

relevant statistics are presented in Table 1. 

Volume calculated by height accumulation was 

checked by comparing it to standard volume 

tables and to the volume calculated using 17 

stem analyzed trees from this study. 

Analysis of variance 

As suggested by our study plan (Zeide, 

1981), stand volume was studied as a function 

of blocking, thinning, pruning, and the 

thinning-pruning interaction. This analysis 

was done both with and without including our 

new control plots. However, in both cases 3 

of the 40 treated study plots were excluded 

since they were severely damaged by previous 

ice storms (Burton 1981b) and no longer 

represented their intended treatments. The 

excluded plots were all pruned to a live crown 

ratio of 25 percent. One plot had a density 

of 70 square feet of basal area and the other 

two had 90 square feet of basal area. To 

study the effect of the above-mentioned 

Table 1. Coefficients used to estimate total cubic foot volume outside bark of trees from diameter 

(DBH); MAF = multiplicative adjustment factor to eliminate logarithmic bias; N = sample size; F = 

calculated F statistic with 1 and S-1 degrees of freedom; p > F = probability of exceeding this F value 

if slope = 0; and adj ~r~ = adjusted It2 

Age N MAF In (A) B F P'F adj R' 
variables on volume growth, accumulated volume 

(present volume, plus the sum of all previous 

cuts) was regressed on categorical variables 

which represented blocking, basal area level, 

pruning area, and the interaction between 

thinning and pruning using the general linear 

models procedure of the SAS statistics package. 

Additionally, Duncan's multiple range test was 

used to determine where the significant 

differences actually ~ccurred. 

A number of FORTw programs and the SAS 

statistical package were used -to collect and 

sumarize the accumulated data for all six 

inventories. Whenever an actual tree volume was 

missing, it was calculated from equation 2. The 

number of trees, the quadratic mean diameter and 

its standard deviation, the average total height 

and its standard deviation, and the average 

basal area per acre were summarized by density 

level. Since the previously mentioned ANOVA 

indicated that volume was affected by both 

density and pruning levels, both of these 

variables were used to describe the effect of 

treatment on total stem volume. 

In order to express more properly the effect 

of density and crown ratio on volume growth, two 

new variables were calculated: volume weighted 

basal area and volume weighted crown 

ratio. Volume weighted basal area is an average 

basal area calculated as follows: 

1 - multiply the initial basal area at age 12 

by the cubic-foot volume at that age; 

2 - calculate the mean of the basal area left 

after thinning at one age and the before 

thinning basal area of the following age; 

3 - multiply these mean basal areas by the 

cubic foot volume which grew during this time 

span ; 

4 - sum the weighted basal areas from (1) and 

(3) above; and 

5 - divide by the volume before thinning at 

the last age. 

Volume weighted crown ratio is calculated in a 

similar manner with crown ratio substituted for 

basal area. These calculations resulted in 

average basal areas of 49, 68, 86, and 102 

square feet per acre respectively for the 

treatment levels of 30, 50, 70, and 90 square 

feet per acre. The volume weighted average live 

crown ratios were respectively 44, 50, and 51 

percent for the treatments 25, 40, and 55 

percent with the unpruned plots having an 

average crown ratio of 55 percent. 

Mean annual increment and its culmination 

Mean annual increment (MI) can be used to 

compare the growth rates of different stands at 

a given point in time and its maximum or 

culmination is usually used to determine 

rotation age. For this analysis, our control 

plots and the previously mentioned storm-damaged 

plots were excluded, the control plots because 

we do not yet have a history of their growth and 

the damaged plots because they are not 

representative of their normal treatments. 

To find the age at which MI is maximized 

the accumulated volumes at each age were 

calculated. Accumulated volume is the 

before-cut volume at any given inventory age 

plus the sum of all previously removed 

volumes. Using this series of ages and 

volumes the technique of Clutter and others 

(1983) was applied. This technique involves 

the fitting of the following equation to the 

yield and age data. 

where : 

Y - yield at time t; t = age of yield data; 

e = the base of the natural logarithm, and 

A and B are estimated coefficients. 

This technique is especially appealing because 

of the simplicity of the equation and the fact 

that the age of culmination for mean annual 

increment is just -Be This equation was 

fitted using a nonlinear package written by 

the authors and the age of maximum MA1 was 

determined and used to calculate the expected 

mean annual increment at this age. 

In addition to the calculation of the actual 

maximum, a sensitivity analysis was done to 

determine the range of practical cutting ages. 

This analysis was done by trying different 

ages in the equations fitted above until a 

mean annual increment 10 percent less than the 

maximum was found. This percent was chosen 

because it was felt that it would encompass 

the acceptable error in actual forest 

management practice. 

RESULTS AND DISCUSSION 

Descriptive stand variables 

In order to present a full picture of stand 

development under different thinning regimes 

the average number of trees per 0.1 acre plot 

before and after thinning, quadratic mean 

diameter and its standard deviation before and 

after thinning, average total height and its 

st idard deviation before thinning, and the 

,vcrage basal area per acre before and after 

ttglnning are presented in Table 2. 

Volume 

Volume was calculated in terms of 

merchantable units and for the whole stem. 

For the purposes of this paper only total stem 

volume in cubic feet outside bark is 

presented. Table 3 shows this volume before 

and after thinning for all inventory ages by 

both pruning and density levels. 
Table 2. Stand variables before (B) and after (A) thinning by density level for all measurement 

ages, Data basis: 10, 10, 9, 8 and 5 0.1-acre plots for density levels 30, 50, 70, 90 and control 

plots, respectively. CN = control plots. 

Age, years ............................................................................................... Density 12 15 16 19 2 4 2 7 

level --------- --------- ---------- ---------- ---------- -------- B A B A B A B A B A BA 

Number of plot trees 

TOT = total number of trees. 

TOT 1225 1031 1031 596 596 4 36 436 432 432 2 60 260 217 

Quadratic mean diameter in inches 

Standard deviation of diameter in inches 

Average total height in feet 

Standard deviation of height in feet 

Average Lasal area in square feet per acre 
Table 3. Total stem volume outside bark in cubic feet per acre before (B) and after (A) thinning by 

density level and pruning level for all measurement ages. 

KN = mean for all pruning level; 

CN = control (no pruning). 

Pruning Age, years 

level as ................................................................................... a pct. of 12 15 16 19 2 4 2 7 

Live crown ------- -------- --------- --------- ---------- ------------ B A B A B A B A B A B A 

Density level 30 

Density level 50 

Density level 70 

Density level 90 

2000 

2157 

2917 

2940 

2520 

levels 

6310 

185 2 

2135 

2 2 2 5 

All density 

In addition to the volume present at each 

inventory, the accumulated volume per acre 

produced by each treatment was also calculated. 

This information is presented in Table 4. 

Table 4. Total accumulated stem volume at age 

27 in cubic feet per acre. This is the volume 

at age 27 plus all previously removed volume. 

Pruning 

The most obvious trend in Table 4 is that 

volume increases with both basal area and 

percent of live crown. This can best be shown 

by figures 1 and 2. Figure 1 shows the actual 

accumulated volume present on each study plot 

as function of its actual basal area and 

average crown ratio. Figure 2 is the same data 

which has been smoothed by the following simple 

regression function: 

level as Density level 

a pet of 

live crown 49 68 86 102 all (83) 

4 4 3851 4538 5110 5675 4563 

50 4436 5115 5625 5499 5169 

5 1 4368 5435 5767 6171 5436 

5 5 4565 4985 5735 5815 5274 

all (49) 4253 5025 5570 5812 5119 2 VOL=a +b (BA) +c (BA') +d (CR) +e (CR ) +f (BACR) (3) 
where : 

VOL = the accumulated tokal cubic foot 

volume outside bark; a through f are estimated 

coefficients; BA = volume weighted average 

basal area; CR = the volume weighted average 

crown ratio; and BACR = BA x CR. 

Analysis of variance 

When an analysis of variance was calculated 

for the total outside bark cubic foot volume, 

it was shown that the density level and the 

pruning level were highly significant. These 

relationships were significant regardless of 

whether or not the control plots were included 

in the analysis. The block and the interaction 

between pruning and density level were 

nonsignificant. It is interesting to note that 

the previous progress report (Burton 1976) did 

not show pruning level to be a significant 

factor in volume yield. 

VOLACC 

In order to examine more thoroughly the 

effects of pruning on the volume yield of 

loblolly pine, as mentioned above, a Duncan's 

multiple range test was used. This test 

revealed that the accumulated cubic foot volume 

increased significantly with the increase in 

crown ratio among the pruning treatments tried. 

The unpruned plots had a lower volume than that 

of trees pruned to a 55 percent live crown 

ratio (actual average if 51 percent), but this 

difference was not significant. 

Figure 1. Total accumulated volume at Age 27 

as a function of basal area and crown ratio. 

BA = basal area in square feet per acre; 

CR = length of live crown divided by tatal tree 

height; and VOLACC = cubic-foot volume outside 

bark at age 27 plus all previously removed volume. 

Figure 2. Total accumulated volume at Age 27 

as a function of basal area and crown ratio. 

BA = basal area in square feet per acre; 

CR = length of live crown divided by total tree 

height; and VOLACC = cubic-foot volume outside 

bark at age 27 plus all previously removed volume. 

In addition to a standard analysis of 

variance in which pruning, thinning, blocking, 

and the interaction between thinning and pruning 

were treated as qualitative variables a regression analysis was done on the effect of thinning 

and pruning. The model employed to produce 

Figure 2 was too collinear to trust for significance tests so a more simple model was used. 

In this model, shown below, volume weighted basal 

area and crown ratio were used as continuous 

independent variables and accumulated volume at 

age 27 was the dependent variable. 

VOL = a + b (BA) = c (CR) (4 

where : 

VOL = the accumulated total cubic foot 

volume outside bark; a through c are 

estimated coefficients; BA = volume 

weighted average basal area; and CR = 

the volume weighted average crown ratio. 

The results of this regression ANOVA were that 

basal area level is significaat but pruning 

level is not. 

Culmination of mean annual increment 

The average age at which mean annual 

increment for cubic foot volume growth peaks 

is 25 years. At this age the mean annual increment is about 216 cubic feet per acre per year. 

The ages and their respective mean annual increments for each density and pruning treatment are 

shown in tables 5 and 6 respectively. To get a 

better feel for how the density and crown ratio 

affect mean annual increment this data is also 

presented graphically in figures 3 and 4. 
Table 5. .Age of maximum MA1 of total stem 

volume, 

Pruning 

level as Density level 

a pct of 

live crown 49 68 86 102 all (83) 

44 14 18 2 1 2 3 18 

50 18 2 1 2 3 2 3 2 1 

5 1 17 2 3 23 25 2 2 

5 5 19 2 1 2 5 24 2 2 

all (49) 17 2 1 2 3 2 4 2 2 

Table 6. Maximum MA1 of total stem volume in 

cubic feet per acre. MAI's correspond to the 

ages shown in table 5. 

Pruning 

level as Density level 

a pct of 

live crown 49 6 8 86 102 all (83) 

4 4 168 181 194 210 180 

5 0 175 197 213 207 19 7 

5 1 176 207 * 218 230 206 

5 5 182 191 214 218 2 00 

all (49) 173 194 210 217 216 

AGE 

Figure 4. Maximum annual increment as a 

function of basal area and crown ratio. 

BA = basal area in square feet per acre; and 

CR = length of live crown divided by total tree 

height. 

In addition to the straightforward answers 

obtained for the age and volume of stands with 

maximum mean annual increment, a sensitivity 

analysis was conducted. For each density level 

the age was found when mean annual increment 

was 10 percent less than the maximum. These 

results are presented in Table 7. 

Table 7. Sensitivity analysis of the total 

stem volume at rotation age for all density 

levels. 

Density level 

Age of 49 68 86 102 all (83) 

0.9 MAX (MAI) 11 13 15 16 15 

MAX(MA1) 17 21 23 24 2 2 

O.gMAX(MA1) 28 34 38 39 3 6 

SUMMARY AND CONCLUSIONS 

This study of the effects of thinning and 

pruning on the growth of planted loblolly pine 

is not yet complete but already some valuable 

results have been obtained. As would be 

expected, diameter growth (and thus basal area 

growth) is fastest on heavily thinned plots. 

The current average diameter of the plots 

thinned to 30 square feet of basal area per 

acre is 70 percent better than the control 

Figure 3. Age of maximum mean annual volume in- plots. Neither height growth nor wood density 

crement as a function of basal area and crown ratio. seems to have been affected by the experimental 

BA = basal area in square feet per acre; and treatment. 

CR = length of live crown divided by total tree 

height. Total cubic foot volume yield increases with 

both density and crown ratio. The highest 

yield is 60 percent greater than the lowest. 
Averaged over a11 treatments, mean annual increment culminates at age 22 with an average volume growth of 216 cubic feet per acre per year. 

This age ranges between 14 and 25 years and the 

NAI ranges between 168 and 230 cubic feet. 

The existence of a gradient in total volume 

produced which was related to the density of 

the stand does not agree with the conclusion of 

Wiedemann (1932) and others that within a wide 

range of density, productivity is independent 

of thinning intensity. It shows that there is 

some biological reason to continue the search 

for the best density level aside from finding 

the best distribution of volume from smaller to 

larger stems. This study reveals the direction 

in which the answer lies, but not the actual 

optimum for loblolly pine, since our maximum 

occurs at the limits of the study treatments. 

It is known that the removal of lower, shaded 

branches which consume more photosysnthate than 

they produce increases volume yield (Smith 1962). 

This effect is readily observed in our study. At 

all density levels, except the lowest, volume 

growth is greater when the trees were lightly 

pruned rather than left unpruled. This exception 

strengthens rather than contradicts the rule 

because in the most heavily thinned plots where 

the lower branches were not shaded. growth was 

increased by the presence of these branches. 

This effect, though present, is slight and does 

not show up in our attempts at modeling. 

This paper only examined some basic stand 

description variables and the total cubic foot 

volume growth outside bark. There is much more 

which could be extracted from the collected data 

including an analysis of merchantable volume, but 

that will be more meaningful after the MA1 culminates in a few years. Additionally, there are 

other factors like the effect of ice damage on 

volume growth, and the effects of thinning on 

crown form which remain to be investigated. 

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levels in southern Arkansas. Study Plan 

FS-SO-1117-19. Monticello, AK: University of 

Arkansas, 1981. 6 pp. 
Growth and Yield 

Moderators: 

Harold E. Burkhart 

Virginia Polytechnic Institute 

and State University 

James C. Fortson 

University of Georgia 

Estimating the Amount of Wood Per Acre in 

Loblolly and Slash Pine Plantations in East Texas 1 

J. David Lenhart 2 

Abstract.--Two diameter distribution yield prediction 

svstems are resented for loblollv ~ine (Pinus taeda L.1 

and slash pine (Pinus elliotti Engelm.) 4 L plantations 

-- 

located on non-old-fields in East Texas. A separate system 

was developed for each species based on the initial measurement of the East 

Texas Pine Plantation Research Project permanent plots. 

Loblolly and slash pine plantations established 

on sites converted from mixed pine-hardwood stands 

in East Texas are approaching possible 

utilization. In order to optimize the utilization 

of these plantations, estimation of the amount of 

wood per acre is needed. If the per acre yields 

can be described on a diameter class basis, it 

would assist the forest manager in assigning 

different stumpage prices to various tree size 

classes. 

This paper presents a method to predict the 

stand structure--number of trees per acre by 

diameter classes and individual total tree heights 

by dbh classes--and, subsequently, the amount of 

wood per acre by diameter classes for loblolly and 

slash pine plantations in East Texas. 

PEWHENT PLOT MEASUREMENTS 

The East Texas Pine Plantation Research Project 

(ETPPRP) permanent plots were installed and 

measured during the summers of 1982, 1983 and 

1984. A total of 174 plots were established in 

loblolly pine plantations and 78 in slash pine 

plantations. Each permanent plot consists of two 

subplots--one to remain unthinned, and the other 

will eventually receive thinning treatments 

(Lenhart et al. 1985). The diameter distribution 

yield prediction systems were developed using data 

from the subplots-to-remain-unthinned (regression 

subplots), and the systems were evaluated using 

the subplots-to-be-thinned (evaluation subplots). 

Observed values available for stand structure 

analysis were: 

1. Age-number of growing seasons 

completed-(A). 

2. Stand height-average height of the ten 

tallest trees-(H). 

3. Total number of trees per acre by dbh class- 

(TI. 

4. Number of trees per acre by diameter class. 

5. Minimum diameter-(DMIN). 

6. Arithmetic mean diameter-(DMEAN). 

7. Quadratic mean diameter-(DQMEAN). 

8. Maximum diameter-(DMAX). 

A site index (base age=25 years) value (S) was 

predicted for each plot using appropriate 

equations developed by Blackard (1985a, 1986) 

and Lenhart et al. (1986). 

An exploratory analysis of fitting the Weibull 

distribution to the observed number of trees pet 

acre by diameter class indicated that a 

regression subplot had to have trees in three 

dbh classes or more. If two dbh classes or less 

were occupied, the fitting routines would 

usually fail to find a solution. As a result, 

the number of loblolly pine plots available for 

analysis was reduced from 174 to 77, and the 

slash pine plots were reduced from 78 to 43. 

For the 77 loblolly pine regression subplots, 

average stand parameters are: 

1. Age=9 years. 

2. Height of the ten tallest trees=31 feet. 

3. Site index=72 feet. 

4. Xumber of trees per acre=457. 

5. Hinimum diameter=1.2 inches. 

6. Arithmetic mean diameter=4.2 inches, 

7. Quadratic mean diameterz4.4 inches. 

'Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia. 

'~rofessor, School of Forestry, Stephen F. Austin 

State University, Nacogdoches, Texas 75962. 
For the 43 slash pine regression subplots, 

average stand parameters are: 

"recor~eredtt with techniques developing by 

Burk and Burkhart (1984). The recovery 

process is: 

1. Age=8 years. 

2. Height of the ten tallest trees=27 feet. 

3, Site index=67 feet. 

4. Number of trees per acre=457. 

5. Minimum diameter=1.2 inches. 

6. Arithmetic mean diamete~4.2 inches. 

7. Quadratic mean diameter=4.4 inches. 

a. Location parameter (a) is equal to DMIN. 

b. Shape parameter (c) is calculated by 

solving the following equation: 

(DQMEALI) '-a2-2a (DMEAN-a) 

PREDICTING STAND STRUCTURE AND YIELD 

where: f =The complete gamma function. 

A Weibull parameter recovery procedure 

developed by Burk and Burkhart (1984) was selected 

to fit the Weibull distribution to the regression 

subplots. Diameter distribution yield prediction 

systems for each species are described as: 

c. Scale parameter (b) is obtained using: 

Solve the Weibull distribution to determine 

the proportion (P) of T in each dbh class as: 

Loblolly 

1. Determine : 

where: dl, & d =lower & upper bound of 

a. Number of growing seasons completed since diameter classy 

plantation establishment (A). 

Multiply each P by T to obtain the expected 

number of trees per acre (n) in each dbh 

class. 

b. Number of surviving trees per acre (T) at 

that age. 

c. Average total height of ten tallest trees 

(H) in plantation. If unknown, but site 

index (S) (base age=25 years) is known, 

then predict H using: 

4. Predict the total height (h) of each tree 

with dbh class mid-point dbh (d) (5.@, 6.0, 

etc.) using: 

(This equation was developed by Blackard 

1985a, 1986 and Lenhart et al. 1986.) 

2. Predict: 

a. Dbh of smallest tree (DMIN) in 

plantation, using: 

Where: DMAX=Dbh of largest tree in 

plantation. 

(This equation developed by Blackard 1985b, 

1986.) 

5. Estimate the content (cubic feet, green 

weight, etc.) of the tree representing each 

dbh class mid-point. 

If DMIN is less than 0, DMIN=O. 

b. Quadratic mean dbh (DQMEAN) for 

plantation, using: An equation to estimate the cubic feet of 

wood (CFW) in a planted Loblolly pine 

tree in East Texas is: 

c, Arithmetic mean dbh (DMEAN) for 

plantation, using: (This equation developed by Wiswell et al. 

1986.) 

6. For the Loblolly pine plantation, we now 

know : 

3. Compute the expected number of trees per acre 

for the plantation using the Weibull 

distribution. Weibull parameters are 

a. The number of trees per acre (n) for 

each dbh class. 
b. The cubic feet of wood per tree (CFCJ) 

for each dbh class. 

Multiply CFW by n to obtain the cubic feet of 

wood per acre by dbh class. 

Sum the CEW values across all dbh classes to 

determine the total cubic feet of wood per 

acre. 

By selective summing across specified dbh 

classes, the CFW per acre by various tree 

size groups or different products (pulp, 

chip-n-saw, lumber, plywood, etc,) can be 

calculated. 

Slash 

1. Determine: 

a. Number of growing seasons completed since 

plantation establishment. 

b. Number of surviving trees per acre at 

that age. 

c. Average total height of ten tallest trees 

in plantation. If unknown, but site 

index (base age=25 years) is known, 

then predict H using: 

(This equation was developed by Blackard 

1986, 1985a and Lenhart et al. 1986.) 

2. Predict: 

a. Dbh of smallest tree in plantation, 

using : 

If DMIN is less than 0, DMIN-0. 

b. Quadratic mean dbh for plantation, using: 

DQMEAN= 10 (1.09600-11.70271(1/H)-0.000162166T) 

2 (R ~96%) 

c. Arithmetic mean dbh for 

plantation, using: 

3. Compute the expected number of trees per acre 

for the plantation using the Weibull 

distribution. Weibull parameters are 

"recovered" with technique developed by Burk 

and Burkhart (1984). The recovery process 

is : 

a. Location parameter is equal to DMIN. 

b. Shape parameter is calculated by 

solving the following equation: 

(DQMEAN) 2-a2-2a (,ME,,-a) 

2 -(DMEkN-a) r (1+2/c) / r (l+l/ c)=O 

c. Scale parameter is obtained using: 

Solve the Weibull distribution to determine 

the proportion of T in each dbh class 

as: 

Computer software can be easily developed 

to solve Eq. 7. 

Multiply each P by T to obtain the expected 

number of trees per acre in each dbh 

class. 

4. Predict the total height (h) of each tree 

with dbh class mid-point dbh (d)(5.0, 6.0, 

etc.) using: 

(This equation developed by Blackard 1985a, 

1986.) 

5. Estimate the content (cubic feet, green 

weight, etc.) of the tree representing each 

dbh class mid-point. 

An equation to estimate the cubic feet of 

wood in a planted slash pine tree in 

East Texas is: 

CFW=O.O00838d 1.859736h1.301908 

2 (R =99%) 

(This equation developed by Hackett 1986.) 

6. For the slash pine plantation, we now know: 

a. The number of trees per acre for 

each dbh class. 

b. The cubic feet of wood per tree for 

each dbh class. 

Multiply CF'W by n to obtain the cubic feet 

of wood per acre by dbh class. 

Sum the CFW values across all dbh classes 

to determine the total cubic feet of wood 

per acre. 
By selective summing across specified dbh 

classes, the CFW per acre by various tree 

size groups or different products (pulp, 

chip-n-saw, lumber, plywood, etc.) can be 

calculated. 

EVALUATION 

Loblolly 

Using evaluation subplot values, plottings of 

the differences between observed yields and 

predicted yields against various stand parameters 

indicated no adverse trends. On the average, an 

under-prediction of 44 cubic feet or 7 percent 

occurred. 

- Slash 

Based on the evaluation subplot values, 

plottings of the differences between observed 

yields and predicted yields against various 

parameters indicated no adverse trends. On the 

average, an under-prediction 37 cubic feet or 11 

percent occurred. 

ACKNOWLEDGMENT 

Support from the four participating forest 

industries--Champion International Corporation, 

International Paper Company, Louisiana-Pacific 

Corporation and Temple-EasTex, 1nc.--is 

gratefully appreciated. 

LITERATURE CITED 

Blackard, J. A. Estimating site index. ETPPRP 

Report No. 3. School of Forestry, SFASU; 1985a. 

8 PP. 

Blackard, J. A. Estimating individual tree 

height. ETPPRP Report No. 4. School of 

Forestry, SFASU; 1985b. 22 pp. 

Burk, T. E. and H. E. Burkhart. Diameter 

distributions and yields of natural stands of 

loblolly pine. FMS-1-84. Div. of For, and 

Wild. Resources, VPI&SU; 1984. 46 pp. 

Hackett, T. L. Estimating the cubic foot volume 

of individual slash pine trees planted in East 

Texas. ETPPRP Report No. 8. School of 

Forestry, SFASU; 1986. 11 pp. 

Lenhart, J. D., E. V. Hunt, Jr. and J. A. 

Blackard. Establishment of permanent growth and 

yield plots in loblolly and slash pine 

plantations in East Texas. In: E. Shoulders, 

editor Proceedings, Third Biennial South. 

Silvic. Res. Conf; 1984 November 7-8; Atlanta, 

GA: U.S.D.A. For. Serv. Gen. Tech. Rep. 

SO-54; 

1985:436-437. 

Wiswell, T. J., J. A. Blackard and J. D. 

Lenhart. Estimating the cubic foot volume of 

individual pine trees planted in East Texas. 

ETPPRP Report No. 5. School of Forestry, 

SFASU; 1986. 11 pp. 

Blackard, 3. A. Estimating site index and 

individual total tree height for loblolly and 

slash pine plantations on non=old=fields in East 

Texas. Nacogdoches: SFASU; 1986. 162 pp. 
UPDATE OF LONG TERM LOBLOCLY PINE PLANTATION 

GRO~H AND YIELD STUDY ON THE CLEMSON EXPERIMENTAL FOREST' 

L. E, Nix, A. T. Shearin, and S. K. Cox 2 

ABSTRACT.--Clemson University's long term loblolly pine plantation 

growth and yield study provides the results of 47 years of growth of 

plantations established on old fields in the upper Piedmont of South 

Carolina. Diameter growth has peaked in these plantations and 5s 

apparently decreasing, The reduction in growth rate is not wholly 

explained by the age of the stands or any changes in the thinning 

regime. Unthinned plots average 9.3 inches dbh while thinned plots 

average 11.5 inches dbh. Diameter growth on several of the most 

heavily thinned plots has failed to show the response expected relative 

to the site index. Analysis of the Girard Form Class of thinned versus 

unthinned plots indicates that differences found at age 42 are 

disappearing. Unthinned plots average 79 in FC while thinned plots 

average 80 in FC. A preliminary analysis of the relation between form 

class and diameter class for the sample of trees measured on all plots 

indicates a curvilinear relationship with trees at either end of the 

diameter class range having lower form class values than trees near the 

median diameter class. Average form class values range from a low of 

78 on the poorest plot to a high of 82 on the best plot. Thinning 

effects may primarily be caused by removal of small diameter trees 

which have lower form class values than median diameter trees. Six 

inch dbh trees average 72 FC, 12 inch dbh trees average 81 FC, and 

18 inch dbh trees average 78 FC. 

INTRODUCTION 

Clemson University's Department of Forestry has 

maintained a long-term thinning study for the past 

33 years in old-field Piedmont loblolly pine 

(Pinus taeda L.) plantations on the Clemson 

Experimental Forest in upper South Carolina 

(Shearin et al. 1985). The stands are now 

47 years old and have been thinned 5-6 times 

during the study starting at about age 15 years. 

Low thinnings have been used to maintain residual 

basal area stocking guidelines for treatment plots 

ranging from 75 ft2 to 135 ft2 basal area per 

acre. The stands were planted on abandoned 

agricultural lands by the Works Progress Administration in the late 1930's at 6 x 6, 6 x 7, and 

6 x 8 feet spacing with Coastal Plain loblolly 

stock. Thirty-two study plots ranging in size 

from 0.1 to 0.6 acres with half chain buffers were 

established around 1953 on sites ranging from site 

index base age 50 years (SI ) 76 to 103 on 0 Cecil-Madison sandy clay lo?m soils in various 

stages of erosion. Twenty-two of the original 

plots remain intact, with fifteen of these grouped 

(3-4) at each location, usually including a range 

of basal areas and an unthinned control plot. 

Stand data have been reported for 15 plots which 

have been actively maintained and have an 

unthinned control plot adjacent (Shearin et al. 

'paper presented at the 4th Biennial Southern 

Silvicultural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

'~ssociate Professor, Assistant Professor and 

Research Associate, respectively, Department of 

Forestry, College of Forest and Recreation 

Resources, Clemson University, Clemson, South 

Carolina. 

1985). Thinnings have been conducted at 5-8 year 

intervals or when plot basal area exceeded the 

specified residual guideline by 25 ft2. Growth 

has slowed recently and many of the plots have not 

been thinned in the past eight years. 

In the process of monitoring growth and yield on 

the study plots, Girard form class of sawtimber-size 

trees was measured to facilitate using the form 

class volume tables of Mesavage and Girard (1946) 

to compute sawtimber volumes. Incidental comparison of form class among treatments indicated that 

trees on thinned plots had higher form class 

values than those on unthinned plots and that this 

difference in form at age 42 contributed as much 

as 8 percent of the sawtimber volume difference 

between thinned and unthinned plots (Shearin 

et al. 1985). The current report provides an 

update of the growth and yield values and a 

further analysis of the differences in tree form 

induced by thinning that were reported at age 42. 

Diameter at breast height (dbh) of all trees cs 

each plot was measured (10,1 inch) with a steel 

diameter tape and merchantable height of all 

sawtimber-size trees (dbh 99.5 inches) was 

ocularly estimated to the nearest half log 

(16 foot logs) with the aid of a 16 foot pole, 

Girard form class, total height, and height to a 

6 inch diameter outside bark (dob) of at least 

20 percent of the trees in each one inch diameter 

class on each plot were determined with the aid of 

a tree ladder, a clinometer, and an optical dendrometer, respectively, Swtimber volumes in 

International 114 inch rule were calculated for 

each tree with a computer program using an 

equation and 3 percent form class correction 
factor derived from the Mesavage and Girard (1946) 

form class volume tables by Wiant and Castaneda 

(1977). Pulpwood volumes were calculated using 

the equation of Schumacher and Coile (1960). 

Predictive equations for form class were derived 

using the Statistical Analysis System Genera1 

Linear Models Procedure (SAS, 1985) with dbh, 

relative dbh (tree dbh * plot mean dbh), plot 

basal area and site index as independent 

variables. Tree taper equations and curves were 

derived similarly using tree dbh, dob at 17.3 feet 

(height of upper diameter measurement for Girard 

form class), height to a 6 inch dob and total 

height measurements with the SAS General Linear 

Models Procedure and a quadratic equation form 

assumed to be parabolic in nature. The tree taper 

equations were used to predict tree merchantable 

height to an upper dob equal to 60 percent of dbh 

as prescribed by Mesavage and Girard (1946) in 

using their form class volume tables for trees up 

to 30 inches dbh. The tree taper curves were used 

for graphical comparison of overall tree taper 

among diameter classes, thinning intensities, and 

different site qualities. Taper equation predicted 

merchantable heights (heights to a dob = 60 percent 

dbh) were compared to ocularly estimated merchantable heights using the paired Student's t-Test to 

determine if, in fact, the ocular estimates of 

merchantable heights conformed reasonably to the 

specifications of the Mesavage-Girard form class 

volume tables for merchantable stem volume 

determinations. 

Because there remains little true replication of 

thinning levels across the range of site qualities 

in the intact plots of the study, the plots were 

grouped according to whether they were low, 

medium, or high basal area residual stocking level 

and similarly for site index in order to provide 

replication in statistical comparisons of 

treatment mean values. 

RESULTS AND DISCUSSION 

Volumes per acre and individual tree parameters 

at age 47 can be compared among the four broad 

levels of stocking treatment in Table 1. Highest 

mean sawtimber volumes in this study were produced 

with the mediua residual basal area stocking 

levels (90-100 f t2 / ac) . However, caution should 

be exercised in extrapolating these results to 

other sites and stands since, due to lack of 

replication, the higher stocked, thinned plots 

(1 10-135 ft2/ac) are all on medium to low quality 

sites. In particular, the mean tree volume of the 

higher basal area plots is lower than that of the 

unthinned controls (Table I). This incongruity in 

mean tree volume may be in part due to ocularly 

overestimating merchantable heights on larger 

diameter trees and underestimating it on small 

diameter trees as the estimator invariably tended 

to take merchantability to the base of the live 

crown on larger trees, rather than to a fixed 

upper log dob. The comparison of ocularly estimated 

merchantable heights with those predicted from tree 

taper equations using the Mesavage and Girard 

60 percent dbh rule showed that ocular estimates 

significantly differ from taper equation estimates 

at the .05 level of probability. The ocular 

method overestimated merchantable heights by from 

3 to 14 feet for the I1 to 17 inch dbh classes, 

respectively; but the 10 inch dbh class was 

consistently underestimated by an average of 

6.4 feet or nearly half of a 16 foot log. The 

higher basal area plots average 10.2 inches dbh, 

and thus, tree merchantable heights and volumes 

may have been underestimated. 

There is no statistically significant difference 

in mean Girard form class values among the 

treatments for sawtimber size (dbh '9.5 inches) 

trees (Table I), although the mean form class for 

all thinned piots is greater than that for the 

unthinned plots (Table 2). Mean dbh of thinned 

plots is less than an inch greater than that of 

unthinned plots when only trees >9.5 inches dbh 

are compared, but mean dbh of all trees is more 

than 2 inches greater on thinned than on unthinned 

plots (Table 2). Although mean sawtimber volume 

of thinned plots is nearly 2,000 board feet per 

acre (BF/~c) more than that of unthinned plots 

(Table 2), one of the unthinned plots currently 

has over 20,000 BF/ac; but it is on one the best 

sites of the study ($1 = 96) and has a mean dbh 

50 of only 9.9 inches. One of the thinned plots has 

only 13,000 BF/ac and averages only 10.3 inches 

dbh, yet was thinned repeatedly to 85 ft2 basal 

area per acre residual and was located on a medium 

site (SI = 89). This incongruity in diameter 

growth, 48lume production and site index remains 

to be investigated further. 

Table 1.--Volume and Girard Form Class of Old Field Plantation Loblolly Pine at Age 47 as Influenced by 

Thinning in the South Carolina Piedmont. 

Residual Basal Area Mean Girard Mean Tree Volume Mean Volume per ~cre~ Thinning Yields b 

(sq ft/ac) Form Class (BF-Int k) (BF-Int %) (cordslac) 

L 

Volumes are for trees >9.5" dbh at age 47 years 

Unthinned plots averaged 21 cords per acre of residual trees (4.5" c dbh < 9.6") while thinned plots 

averaged 3.5 cords per acre 
Table 2.--Mean Volume and Stand Attributes for Thinned and Unthinned Old Field Plantation Loblolfy Pines at 

Age 47 in the South Carolina Piedmont. 

Sawtimber Volume Mean DBB~ Hean Girard Mean Basal Area Mean Tree Volume 

(BF-Int k) (inches) Form Class (sq ft/ac) (BF-Int k) 

TWINNED 

17,899 

a Trees >9.5 inches (mean for all trees in parenthes 

At age 42, thinned plots averaged nearly 3 Girard 

form class units higher than did unthinned plots 

(Shearin et al. 1985); but at age 47 the difference 

has diminished to less than 1 Girard form class 

unit and accounts for only about 2 percent of the 

volume difference between thinned and unthinned 

plots. However, it can still be concluded that low 

thinning does not reduce mean form class and may 

actually improve it by removing smaller diameter 

trees that have lower form class. This conclusion 

is supported by Figures 1 and 2 that show the 

relationship of form class to dbh and relative dbh 

as a hyperbolic function. The smallest and largest 

diameter trees have the lowest mean form class and 

median diameter trees have the highest mean form 

class. Although the predictive ability of the 

equations illustrated in Figures 1 and 2 is 

inconsequential for individual trees (r2 = 0.154 

and 0.166, respectively) the narrow 95 percent 

cbnfidence limits indicate that the predicted mean 

form class for each diameter class is reasonably 

valid. The equations derived for both Figures 1 

and 2 are statistically significant at the .05 

level, but do not necessarily represent a strong, 

definitive relationship because of the very low 

coefficient of determination (r2) , i. e. , predictive 

functions other than that of an hyperbola may 

describe equally well the relationship between form 

class and dbh and relative dbh. However, using the 

SAS General Linear Models Procedure and a quadratic 

equation form gave the highest r2 values of the 

several equation forms that were tried. Based on 

the predictive functions of Figures 1 and 2, mean 

form class values of 6 inch dbh trees equals 72, 

that of 12 inch dbh trees equals 81, and that of 

18 inch dbh trees equals 78. Although not really 

indicating great differences in form class for 

sawtimber sized trees (dbh >9.5 inches), Figures 1 

and 2 demonstrate a range in mean form class 

values of 78 to 81 for trees of sawtimber size in 

the study (10 to 19 inches dbh). 

Figures 3, 4, and 5 illustrate the taper or form 

of trees in the range of diameter classes found on 

the study plots as they were grouped in high, 

medium, and low site index groups, respectively. 

The effect of site index, of course, is to alter 

tree height for a given diameter class, i.e., the 

better the site, the taller the tree and, thus, 

the better the form because of less overall 

average taper. However, close examination of 

is) 

Figures 3-5 indicates that degree of curvature of 

the tree taper curves may be a good indicator of 

form, i.e., the greater the curvature, the better 

form the tree has for a given diameter and total 

height combination. The least desirable tree 

taper is a straight line (no curvature) which 

represents a conical tree form and the least 

amount of tree volume for a given diameter and 

total height combination. The taper curves of the 

trees in the smallest and largest diameter classes 

have the least amount of curvature, indicating the 

poorest form, while the curves of trees of the 

median diameter classes have the greatest 

curvature, indicating the best overall tree form. 

Since Figures 1 and 2 indicate a hyperbolic 

relationship of diameter class and form based on 

Girard Form Class measurements, it is significant 

that overall tree form also seems to follow a 

similar functional relationship with diameter 

class. This indicates that the quality of overall 

tree form may be well-described by Girard Form 

Class. 

The effects of diameter class and site quality 

on overall tree taper or form is illustrated in 

Figures 6, 7, and 8 which depict the taper curves 

of trees of the 9, 13, and 16 inch diameter 

classes, respectively, as they are affected by the 

site index differences in the plot groups. 

Differences in site index do not vary greatly 

among groups (76 to 96), but appear to significantly affect tree form. It appears from the 

degree of curvature of the taper curves that the 

median diameter class (13 inch dbh class) has the 

best form except in the high site group, where the 

16 inch dbh class may have equally as good form. 

However, 16 inch dbh trees may not be in the 

largest diameter class in the high site group as 

there were some 17, 18, and 19 inch dbh trees on 

plots in this site group. In the 13 inch dbh 

class (Figure 7), the effect of site quality 

appears to be complex in that the low site group 

tree taper curve has the greatest curvature, 

indicating the best form for that diameterlheight 

combination. However, the high site group has the 

tallest 13 inch dbh trees and, therefore, the best 

(meaning the least) overall average taper for that 

diameter class. Interpretation of the effects of 

site quality on tree form is, thus, confounded by 

the combined effects of site quality on tree 

height and on the diameter growth response at a 

given stocking density. The average tree diameter 
6 0 I'I.I.~ 

5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 

Dan (inches) 

Figure 1.--Relation of Girard form class to tree dbh with predicted 

form class for Clemson thinning study (278 trees). 

RELDBH 

Figure 2.--Relation of Girard form class to relative tree dbh with 

predicted form class for Clemson thinning study (278 trees). 

(Relative dbh tree dbhlplot mean dbh). 
Figure 4.--Tree taper derived from four diameters 

and heights of loblolly pines in the high site 

group of the Clemson study. 

~TIfeetJ 

too 1 

OIR (inches] 

OCLS *-*-n 9 0-5B 10 €6 1 8-8-8 12 E-E--E 13 FF-F 111 15 H-U 16 4+i 19 

Figure 4.--Tree taper derived from four diameters 

and heights of loblolly pines in the medium site 

group of the CSemson study. 

Figure 5.--Tree taper derived from four diameters 

and heights of loblolly pines in the low site 

group of the Clemson study. 

is greater on a better site at a given stocking 

level than on a poorer site. Thus, for the sake 

of comparing tree taper and differing site 

quality, it might be better to compare the taper 

of trees according to relative diameter class 

rather than actual diameter class as has been done 

in Figures 6-8. 

If degree of curvature of a generalized tree 

taper curve is an indication of tree form quality 

then, in general, the best form for a given 

diameterlheight combination may occur on poor 

sites as indicated in Figure 5, the low site 

group, where all but the trees in the smallest 

diameter class seem to have taper curves with more 

curvature (better form) than do trees of the same 

diameter classes in the medium and high site 

groups of the study. Caution must again be 

suggested here as the taper curves developed for 

the trees in this study were assumed to be of the 

same form (quadratic) dong the entire tree and 

across all sites and treatment combinations and 

were based in part on rather crude measurements of 

upper stem diameters. A11 that is intended here 

is to suggest that tree form may be a very complex 

phenomenon and that assumptions regarding the 

effects of thinning, site quality, and diameter 

class on tree taper should be carefully 

considered. 

It is generally assumed that because thinning 

increases the rate of diameter growth of residual 

trees and, thus, increases mean diameter in 
, , 0 , , , , , I,. , . ,.---777 

012'345678910 

OIe [inches] 

51-GRP ~--t+ Hi +-+ s LO E.-E-3 NE 

Figure 6.--Tree taper derived from four diameters 

and heights of 9 inch dbh loblolly pines in high, 

medium and low site groups of the Clemson study. 

0 12 3 U 5 6 7 8 910li121314 

OlRI inches] 

51-GRP -HI +++LO O-E-ONE 

Figure 7.--Tree taper derived from four diameters 

and heights of 13 inch dbh loblolly pines in high, 

medium and low site groups of the Clemson study. 

DIR I inches 1 

SI-GRP - HI +-+ * LO 0-B-a ME 

Figure 8.--Tree taper derived from four diameters 

and heights of 16 inch dbh loblolly pines in high, 

medium and low site groups of the Clemson study. 

relation to height within a stand, it, therefore, 

mathematically ihcreases taper or reduces form 

quality. This is true only if one assumes that 

tree form is represented by an average tree taper 

function such as tree diameter (in) + tree height 

(ft) = average reduction in diameter per foot of 

height. The results of this study indicate that 

thinning does not reduce form quality, at least as 

measured by Girard Form Class, and in fact, may 

improve the form of the residual stand if low 

thinnings are conducted. These results also 

indicate that form, as measured by Girard Form 

Class, varies greatly within a diameter class, but 

is better in median diameter classes than in the 

smallest and largest diameter classes. Whole tree 

taper or form may closely follow Girard Form Class 

in this diameter class relationship. Site quality 

may play an inverse role in form quality in that 

tree form, as measured by Girard Form Class and 

crude taper curves, was best in the low site group 

of this study for a given tree diameter/height 

combination, although tree height increased for a 

given diameter as site quality increased, 

resulting in improved overall average form 

(reduced average taper). 

An interesting postscript to this study results 

from an investigation of a stand of the same age 

and adjacent to a group of the thinning plots that 

was converted into a seed production area 25 years 

ago by cutting (thinning) it back to about 25 trees 
per acre. Measurements of 39 of these trees 

resulted in a mean Girard Form Class of 82 and 

crude taper curves that indicated a no less 

desirable overall tree taper or form. These 

results serve to illustrate quite well that tree 

form is not a simple matter but rather is very 

complex, as is typical of most biological 

phenomena. Most assumptions about thinning and 

tree form have been clouded by the often-reported 

poor form of open-grown trees and the simple 

mechanistic theory of tree bole shape (Larson 

1963). Perhaps recent work regarding the 

biological nature of tree bole form and how it 

comes about, McHahon (1975), Wilson and Archer 

(1979) and Barker (1980), provides the clue that 

trees, like other biological organisms, are 

energetically efficient and put energy into growth 

where it is most demanded. Thus, the distribution 

of cambial growth along the bole of a tree seems 

to be a complex response to availability of 

photosynthate and to stress stimuli and serves to 

prevent potential fracture of the stem without 

excessive redundancy or inefficient energy 

expenditure. The effects of wind sway, crown 

loading, live crown ratio, diameterlheight ratio, 

site quality, stocking levels, genetic variation, 

and age will all have to be considered in 

adequately defining the response of tree form to 

cultural treatments. At the very least the 

results of this study should point out the need to 

adequately identify measurable tree characteristics 

that are nore closely associated with and will 

more accurately predict tree taper than will 

diameter class, site index, and basal area per 

acre. 

ACKNOWLEDGMENTS 

LITERATURE CITED 

Barker, J. E. Bole growth patterns of Pinus 

radiata in relation to fertilization, 

stress, and crown growth. New Zealand Jour. of 

For, Sci. 10(2):445-459; 1980. 

Larson, P. R. Stem form development of forest 

trees. For. Sci. Monogr, 5:42 pp.; 1963. 

McMahon, T. A. The mechanical design of trees. 

Scientific American 233(1):92-102; 1975. 

Mesavage, C.; Girard, J. W. Tables for estimating 

board foot volumes of timber. USDA For. Ser. 

(unum. pub,), Washington, D.C.; 1946. 94 pp. 

SAS. SAS User's Guide: Statistics. Version 5 

Edition, SAS Institute, Inc.; Cary, N.C.; 1985. 

956 pp. 

Schumacher, F, X.; Coile, T. X. Growth and yield 

of natural stands of southern pines. T, S. 

Coile, Inc. Durham, N.C.; 1960. 115 pp. 

Shearin, A. T.; Nix, L. E.; Collins, R. T. 

Thinning from below affects the Girard form 

class and final volume of loblolly pine 

plantations, In Proceedings 3rd Biennial 

Southern ~ilvizltural Research Conference, 

Nov. 7-8, 1984, Atlanta, GA.; 1985:227-230. 

Wiant, H. V.; Castaneda, F. Hesavage and GPrardls 

volume tables formulated. Bureau of Land Mgt. 

Resource Inventory Notes 4; 1977. 8 pp. 

Wilson, G. F.; Archer, R. R. Tree design: some 

biological solutions to mechanical problems. 

Bioscience 29:293-298; 1979. 

The authors wish to thank Mark Augspurger, 

Research Associate, Department of Forestry, 

Clemson University, for his assistance in 

collecting the field data. 
AH ECOLOGICAL DERIVATION OF STAND STRUCTURE IN 

BALANCED UNEVEN-AGED LOBLOLLY-SHORTLEAF PINE 

STANDS OF THE WEST GULF REGION-LJ 

2 / James M. Guldin - 

Abstract,--A theoretical stand structure based 

on crown area was compared with left-truncated 

negative exponential and Weibull models from 

three uneven-aged stands of loblolly-shortleaf 

-- (P. taeda L.-2. echinata Mill.) pine in southern 

Arkansas. When fit to observed merchantable 

distributions, the crown area model was slightly 

less precise than the statistical models. In a 

stand with balanced submerchantable structure, 

the crown area model was a better fit than the 

extended merchantable distribution statistical 

models; in a stand with unbalanced submerchantable structure, the reverse was true. When 

fit to full distributions, the statistical 

models were best overall, but the crown area 

model was best in the merchantable component. 

fiefinements in the ecologically-based crown area 

model may improve tk assessment of stem 

density, stocking, and structure of sabmerchantable classes in uneven-aged stands. 

INTRODUCTION 

Uneven-aged silviculture embodied in the 

selection system clearly works+well when 

properly applied to loblolly-shortleaf (Pinus 

taeda L;-P. echinata Mill.) pine stands of the 

West Gulf region (Reynolds 1969, Murphy and 

Farrar 1982a, 1983, Reynolds et al. 1984, Farrar 

et al. 1984, Rainey 1986). As a valid 

silvicultural alternative for the contemporary 

forester, the selection method allows the 

provision of income from small tracts, 

inexpensive rehabilitation of cutover or 

understocked stands, production of large 

high-quality timber, and the aesthetic advantage 

of minimal harvesting disturbance (Hann and Bare 

1979, Baker 1982, Baker and Murphy 1982). 

One reason for the success of the method in 

the loblolly-shortleaf pine type in this region 

is the reproductive proclivity-of loblolly pine, 

which produces adequate seed crops annually and 

large crops on a 3- to 6-year cycle (Grano 

L' Paper presented at the Fourth Biennial 

Southern Silvicultural Research Conference, 

Atlanta, Georgia, November 4-6, 1986. 

1' Assistant Professor, Department of Forest 

Resources, Arkansas Agricultural Experiment 

Station, University of Arkansas at Manticello, 

Monticello, AR 72655. 

1967). With regeneration success not limited by 

the absence of seed, pine usually becomes 

abundantly established in the understory gaps 

resulting from cutting cycle harvests. Yet, just 

as the shift in regulating uneven-aged stands 

from the volume control-guiding diameter limit 

methodology to the basal area - diameter limit - 

Q-factor (BDQ) technique was made to more 

objectively quantify the development of 

merchantable classes below the guiding diameter 

limit (Farrar 1981), so too should 

silviculturists learn more about the origin, 

numbers, adequacy of stocking, and dynamics of 

submerchantable classes. This is especially 

true when considering the application of 

uneven-aged methodology to species that are more 

irregular than loblolly pine in their 

regeneration dynamics. 

Efforts to model the submerchantable structure 

of uneven-aged stands have been limited by the 

absence of data collected in submerchantable 

diameter classes. Assessments of regeneration 

adequacy are usually made using predicted values 

obtained by extrapolating the stem densities and 

Q-factor of a merchantable negative exponential 

* model into the submerchantable classes (Moser 

1976, Farrar 1481, Murphy and Farrar 1982b, 

Farrar 1984). A Weibull model can also be 

extrapolated in this fashion, but requires the 

inconsistent assumption of maintaining the 

left-truncation point in the equation and 

solving the equation for dbh classes less than 
the truncation point. These procedures provide 

silviculturally reasonable answers, but are 

invalid under strict statistical assumptions. 

Regeneration surveys using these extrapolation 

methods typically result in submerchantable stem 

density bein5 assessed as either adequate or 

overwhelming . Murphy and Farrar (1981) 

speculated that the lack of fit of the negative 

exponential distribution to merchantable 

uneven-aged stand structures was most pronounced 

in the lower diameter classes; whether this 

trend extends to submerchantable classes has not 

been explored. Further, the biological basis 

for applying the statistical models to 

uneven-aged stands has been discussed only in 

the broadest terms (Meyer.1952, .Leak 1964, 

Baihy and Dell 1973). 

As an alternative, it might be possible to 

derive the structure of a balanced uneven-aged 

stand based on ecological rather than 

statistical properties. Uneven-aged stands have 

their natural counterpart in old-growth stands, 

which are presumed to regenerate by the 

gap-phase regeneration strategy (Bray 1956, 

Oliver 1981). The mortality or harvest of a 

mature tree in an uneven-aged stand will create 

an opening in the overstory canopy; under ideal 

conditions, a clump of regeneration will become 

established beneath that opening. Given the 

simplest action of uneven-aged stand dynamics, 

only one tree in the regeneration clump will 

achieve the stature of the tree whose demise 

created the initial gap. By such logic, 

uneven-aged stand dynamics can be envisioned as 

a progressive development of horizontal 

projections of crown areadamong trees of 

increasing size. 

Several simplifying assumptions are made in 

deriving this crown area model, First, the 

entire unit area is assumed to brr. exactly 

occupied with horizontal crown projections. 

Thus, no adjustment for crown overlap or 

underoccupancy is required. A second assumption 

is that the progressive development of size 

classes is linear with time; this implies that 

the horizontal crown projection in each diameter 

class is constant. Finally, the crown area 

between size classes is assumed to be equal, 

from the 1" class through the large~t~observed 

class in the stand. Given these assumptions, 

the synthesis of a crown area model of stand 

structure is straightforward. 

2 

Thus, this paper represents an initial effort 

to derive uneven-aged stand structure from 

rudimentary ecological considerations of 

uneven-aged stand dynamics. 

Three standsewere included in this study. The 

first is the Selection #2 stand of the Methods 

of Cutting Study on the Crossett Experimental 

Forest, located in Ashley County, Arkansas; the 

diameter distribution in this stand ranges from 

4" to 31" (Farrar 1981). The two remaining 

stands are located on lands managed by Deltic 

Farm and Timber Co., Inc., a subsidiary of 

Murphy Oil Co., of El Dorado, Arkansas, Both of 

these stands represent full diameter distributions, which include submerchantable as well 

as merchantable classes. Deltic Stand 1 is 

160-acre uneven-aged stand located in Union 

County, Arkansas. This stand received a 

cutting-cycle harvest in the spring of 1986; the 

stand was sampled (at roughly a 10% intensity) 

in the summer of 1986 to assess logging damage 

in the residual stand. Diameter classes in this 

stand range from 1" to 20". Deltic Stand 2 is a 

2.5-acre study area within a GO-acre management 

unit, also in Union County, Arkansas. On this 

study area, all stems greater than 0.5" were 

mapped and measured. Diameter classes range 

from 1" to 22". Crown radii along cardinal 

directions were taken from a sample of 31 trees 

in Stand 2. 

A regression of crown area (determined by the 

quarter-ellipse summation method) versus dbh was 

developed using the crown radius data from Stand 

2, as follows: 

2 

CA = 10.321737 * D + 1.986642 * D , 

where CA is the horizontal projection of crown 

area of a given tree, and D is the diameter at 

breast height .for that tree (R2= 96.9 percent, 

= 468.993, P < 0.000). In each stand, 

Th(e2'e2~dwn area for each diameter class was 

determined by dividing the area of an acre by 

the number of diameter classes (from the 1" 

class through the class containing the largest 

tree). The regression equation was used to 

determine the crown area of a single tree at the 

midpoint of each dbh class, and ehe stem density 

per acre in each dbh class was obtained using a 

straightforward expansion factor calculation. 

Left-truncated negative exponential and 

Weibull models were also fit to each stand. 

Goodness of fit for these models was evaluated 

using root mean squared deviation and fit index, 

formulas for which are presented in Table 1 

(Farrar et al. 1984). Negative exponential 

models were tested by iterative 0.001-Q factors; 

the final models selected were those which 

minimized root mean squared deviation. Weibull 

models were fit using the maximum likelihood 

method (Zutter et al. 1982). 

The Crossett Selection #2 stand was fit with a 

left-truncation point of 3.5". Each Deltic 

stand was fit with left-truncation points of 

3.5" (merchantable distribution models) and 0.5" 

(full distribution models). The Deltic stands 

were also evaluated by extension of the 

merchantable models into the submerchantable 

classes (extended merchantable distribution 

models) 

2/ Farrar, R. M. ; Guldin, J.M. Unpublished 

data, USDA Forest Service, Monticello, AR, 
TABLE I. Goodness of fit indices for 

comparisons between observed and expected data. 

a. Root Mean Squared Deviation, RMSD 

b. Fit Index, FI 

where n = number of diameter classes being 

evaluated 

Yi = observed number in the ith diameter 

h class 

Yi = expected number in the ith diameter 

- class 

Y = mean observed number of stems per 

diameter class 

RESULTS 

.Merchantable Bistribution models 

In the Crossett Selection #2 stand, all three 

.models fit the observed stand structure fairly 

closely (Figure 1). The crown area model 

predicts more trees than the other models in the 

smallest (4"-5") and largest (25"+) dbh classes, 

but predicts fewer trees than the others in the 

6"-20" classes. The statistical models fit the 

observed data most precisely .(Table 2a). 

All three methods provide reasonable 

approxiaations of the-merchantable component of 

Deltie Stand 1 (Figure 2). The crown area model 

is best through a fairly broad range of the 

sawtimber classes, but overestimates the 

observed numbers of the largest sawtimber 

classes. All three models predict fairly 

similar stem densities from the 4" through the 

11" classes and show a good fit of the observed 

data (Table 2b), with the range of the fit index 

less than one percent among the three models. 

For the slightly irregular Deltic Stand 2, 

reasonable approximations of the observed data 

TABLE 2. Goodness-of-fit results for 

comparisons of merchantable distribution models. 

MODEL RMSD FI 

a. Crossett Selection /I2 

Negative exponential 1.0413 0.9498 

Weibull 1.3422 0.9164 

Crown Area 1.7434 0.8618 

b. Deltic Stand 1 

Negative exponential 2.2237 0.9233 

Weibull 2.0127 0.9267 

Crown Area 2.2917 0.9193 

c. Deltic Stand 2 

Negativeexponential 3.2465 0.6844 

Weibull 2.9234 0.7233 

Crown Area 3.1406 0.7173 

DBH 

Figure 1. Merchantable distributio 1 models versus original data, 

Crossett Selection /#2 stand, TPA = trees per acre; DBH = diameter at 

breast height. 
are again obtained with all three models (_Figure 

31, though with slightly less precision (Table 

2c). All three models are fairly uniform in the 

8" class and larger, but the crown area model 

appears to more precisely predict the high stem 

density in the 4" class, which possibly accounts 

for its better fit than the negative exponential 

model. 

Extended merchantable distribution models 

In Deltic Stand 1, the extended merchantable 

statistical models fit the observed data better 

than the crown area model (Figure 4 and Table 

3a). This is attributed to the even-aged 

character of the submerchantable classes, 

as judged by their bell-shaped normal curve 

Figure 2. Merchantable distribution models versus original data, Deltic 

Stand 1. TPA =. trees per acre; DBH = diameter at breast height. 

I I 8 

I 

4 I 0 I 1Z I 

18 I 

ae I 

24 

DBH 

Figure 3. Merchantable distribution models versus original data, Deltic 

Stand 2. TPA = trees per acre; DBH = diameter at breast height. 
fom. The even-aged trait is probably due to 

the development of regeneration following the 

1979 cutting cycle harvest, coupled with the 

absence of regenaation (due to the absence of 

cutting) in the years between 1979 and 1986. 

Regeneration is expected in this stand in the 

fall of 1985, following*the cutting-cycle 

harvest of the preceding spring, and this 

generation of reproduction will probably 

re-estgblish the uneven-aged character of 

decreasing numbers through the submerchantable 

classes. If the one-inch class is not included 

in the goodness of fit test, zhe fit of the 

crown area model (0.7110) is better than the 

negative exponential (0.7088) but poorer than 

the Weibull (0.7487); if both the one- and 

two-inch.classes are ignored, the fit of the 

crown area model (0.7337) is better than either 

the Weibull (0.6948) or the negative exponential 

(0.6906) models. This suggests an age-related 

Table 3. Goodness-of-fiC results for 

comparisons of e~tended merchantable 

distribution models. 

HODEL RMS D F I 

a. Deltic Stand 1 

Negative exponential 12.8581 0.6346 

Weibull 12.5745 0.6371 

Crown area 33.6321 -1.2818 

b. Deltic Stand 2 

Negative exponential 46.1537 0.2183 

Weibull 42.6342 0.1836 

Crown area 21.8272 0.8107 

character to submerchantable structure in 

uneven-aged stands, which existing theory on 

uneven-aged structure fails to address. 

Deltic Stand 2 is more balanced in its submerchantable structure, and the crown area model 

fits much better than either the Weibull or the 

negative exponential (Figure 5 and Table 3b). 

The extended merchantable statistical models 

drastically underestimate submerchantable stem 

density. This suggests that the traditional 

method of evaluating regeneration adequacy in 

uneven-aged stands may be unreliable, and has 

the potential to result in understocking of the 

submerchantable classes. 

Full distribution models 

When full distribution models are fit to the 

observed data in Deltic Stands 1 and 2 (Figures 

6 and 7, respectively), the statistical models 

give better results than the crown area models 

(Tables 4a and 4b). In Deltic Stand 1, this is 

due to the previously-noted overestimation of 

the 1" class by the crown area model. In Deltic 

Stand 2, the crown area model underestimates the 

observed data in the submerchantable classes 

more than the statistical models. 

However, in both Deltic stands, the fulldistribution statistical models overestimate the 

observed number of pulpwood-sized stems, most 

prominently in Deltic Stand 2. When the 

merchantable components of the three fulldistribution models are compared to the observed 

merchantable distributions, the crown-area model 

has the best fit (Tables 5a and 5b, respectively). This will result in better volume 

estimates with the crown area model than with 

the full-distribution statistical models. 

- QRIGIWAL DATA - 

DBH 

Figure 4. Extended merchantable distribution models versus original 

data, Deltic Stand 1. TPA = tregs per acre; DBH = diameter at breast 

height. 
CONCLUSIONS 

Grown area derivation appears to be a 

promising technique for characterizing submerchantable stand structure in uneven-aged stands 

of loblolly-shortleaf pine in the West Gulf 

region. A simple crown area approach produced 

models of merchantable stand structure which 

were only slightly less precise than fitted 

left-truncated negative exponential and Weibull 

statistical models. Further, in a stand with a 

balanced submerchantable structure, the crown 

area model provided a dramatically better fit 

of submerchantable stem density than the ex- tended merchantable distribution statistical 

models. However, in a stand of unbalanced 

submerchantable structure, the reverse was true. 

Finally, full-distribution statistical models 

I I 1 I I I I I 

8 4 8 12 16 ab 24 

DBH 

Figure 5, Extended merchantable distribution models versus original 

data, Deltic Stand 2. TPA = trees per acre; DBH = diameter at breast 

height. 

- ORIGWIU MTA 

--I-* llE6, opp. 

'L - aaDvnIrwu, 

--.-I YUBUL 

Figure 6. Full distribution models versus original data, Deltic Stand 

1. TPA = trees per acre; DBH = diameter at breast height. 
Table 4. Goodness-of-fit results for comparisons 

of full distribution models, 

provided a better overall fit than the crown 

area model, but the crown area model fit better 

in the merchantable conpone:,, 

MODEL RMSD FI 

a. Deltic Stand 1 

Negative exponential 12.5278 0.6502 

Weibull 10.8655 0.7302 

Crown area 33.6321 -1.2818 

;b. Deltic Stand 2 

Negative exponential 15.1464 0.9084 

Weibull 13.2642 0.9266 

Crown area 21.8272 0.8107 

Table 5. Goodness-of-fit results for comparisons 

-of merchantable component of full distribution 

models. 

MODEL RMSD FI 

a. Deltic Stand 1 

Negative exponential 2.5683 0.8992 

Weibull 3.9132 0.7701 

Crown area 2.2917 0.9193 

b. Deltic Stand 2 

Negative exponential 14.8400 -1.8607 

Weibull 7.1601 -0.2886 

Crown area 3.1406 0.7173 

This simple crown area model represents a rudimenrary ecological derivation of uaeven-aged stand 

dynamics. The approach Is consistent with the 

current understanding of gap-phase regeneration 

strategies upon which the regeneration ecology of 

uneven-aged stands is based. In this sense, the 

model has a conceptual appeal aver statistical 

representations of uneven-aged structure, which 

have no readily-discernible ecological basis. 

Silvicultural implications of this approach are 

in the quantificati~n of regeneration success in 

submerchantable classes, Clearly, it is important 

to know how many stems one might expect in a given 

size class before one pronounces an observed number 

as adequate. Traditional methods of determining 

adequate numbers of submerchantable classes, involving submerchantable extensions of merchantably 

based statistical models, appear to seriously 

underestimate the number of trees required to 

maintain a balanced uneven-aged stand. Crown 

area models of stand structure may provide for 

more accurate regeneration assessment through 

improved methods of evaluating both stem density 

and stocking in suhmerchantable classes. 

This research was supported by Arkansas 

Agricultural Experiment Station Project 1136 and 

U.S. Forest Service Cooperative Research Project 

19-82-052 with the Southern Forest Experiment 

Station, Forestry Sciences Lab, Monticello, AR. 

The cooperation and assistance of Deltic Farm 

and Timber, Inc., is greatly appreciated. 

----. a. MP* 

- - m 

--- Elm 

Figure 7. Full distribution models versus original data, Deltic Stand 

2. TPA = trees per acre; DBH = diameter at breast height. 
LITERATURE CITED 

Bailey, Robert L.; T. R. Dell. Quantifying 

diameter distributions with the Weibull 

function. For Sci. 19:97-104; 1973. 

Baker, James B. Natural regeneration of 

loblolly-shortleaf pine. In: Proceedings, Low 

Cost Alternatives for Regeneration of Southern 

Pines; 1982 June 16-17; Athens, GA; 

1982:31-50. 

Baker, James B.; Murphy, Paul A. Growth and 

yield following four reproduction cutting 

methods in loblolly-shortleaf pine stands - a 

case study. So. J. Appl. For. 6(2):66-74; 

1982. 

Bray, J. Roger, Gap-phase replacement in a 

maple-basswood forest. Ecology 37:598-600; 

1956. 

Farrar, Robert M., Jr. Density Control - natural stands. In: Karr, B. L.; Baker, J. 

B.; Monaghan, T., eds. Proceedings of the 

symposium on the loblolly pine ecosystem (West 

Region); 1984 March 20-22; Jackson, MS; 

Mississippi Cooperative Extension Service, 

Mississippi State, MS: 1984:129-154. 

Farrar, Robert M. . Regulation of uneven-aged 

loblolly-shortleaf pine forests. In: Barnett, 

J, P., ed. Proceedings of the First Biennial 

Southern Silvicultural Research Conference; 

1980 Novemb,er 6-7; Atlanta GA: 1981:294-304. 

Farrar, Robert M., Jr.; Murphy, Paul A,; 

Willett, R. Larry. Tables for estimating 

growth and yield of uneven-aged stands of 

loblolly-shortleaf pine on average sites in 

the West Gulf area. Bulletin 874. 

Fayetteville, AR; Arkansas Agricultural 

Experiment Station; 1984. 21pp. 

Grano, Charles X. Growing .loblolly and 

shortleaf pine in the midsouth. Farmers' 

Bulletin No. 2102. Washington, D.C.; U.S. 

Department of Agriculture; 1967. 27pp. 

Hann, David W.; B. Bruce Bare. Uneven-aged 

forest management: state of the art (or 

science?), Gen. Tech. Rep. INT-50. Ogden, UT; 

U.S. Dept. Agriculture, Forest Service, 

Intermountain Forest and Range Experiment 

Station; 1979. 18pp. 

Leak, William B. An expression of diameter 

distribution for unbalanced, uneven-aged 

forests. For. Sci. 10339-50; 1964. 

Meyer, H, Arthur. Structure, growth, and drain 

in balanced uneven-aged forests. J. For. 

50:85-92; 1952. 

Moser, John W,, Jr. Specification of density 

for the inverse j-shaped diameter 

distribution. For. Sci. 22(2):177-180; 1976. 

Murphy, Paul A.; Farrar, Robert M. A test of 

the exponential distribution for stand 

structure definition in uneven-aged 

loblolly-shortleaf pine stands. Research Paper 

SO-164. New Orleans, LA: U,S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1981. 4pp. 

Murphy, Paul A.; Farrar, Robert M. Interim 

models for basal area and volume projection of 

uneven-aged loblolly-shortleaf pine stands. 

So. J. Appl. For. 6:115-119; 1982a. 

Murphy, Paul A.; Farrar, Robert M. Calculation 

of theoretical uneven-aged stand structures 

with the exponential distribution. For. Sci. 

28(1):105-109; 1982b. 

Murphy, Paul A.; Farrar, Robert M., Jr. 

Sawtimber volume predictions for uneven-aged 

loblolly-shortleaf pine stands. So. J. Appl. 

For. 7:45-50; 1983. 

Oliver, Chadwick Dearing. Forest development in 

North America following major ddsturbances. 

For. Ecol. Man. 3:153-168; 1981. 

Reynolds, R.R. Twenty-nine years of selection 

timber management on the Crossett Experimental 

Forest. Research Paper SO-40. New Orleans, 

LA: U.S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1969. 19pp. 

Reynolds, R.R., Baker, James B.; Ku, Timothy T. 

Four decades of selection management on the 

Crossett farm forestry forties. Bulletin 872 

Fayetteville, AR; Arkansas Agricultural 

Experiment Station; 1984. 43pp. 

Rainey, L.C. 1986. Personal communication. 

Deltic Farm and Timber Co., Inc.; Murphy Oil 

Building, El Dorado, AR. 25 March 1986, 

Zutter, Bruce R.; Oderwald, Richard G.; Farrar, 

Robert M., Jr.; Murphy, Paul A. WEIBUL - A 

program to estimate parameters of forms of the 

Weibull distribution using complete, censored, 

and truncated data. Publication No. FWS-3-82. 

Blacksburg, VA: Virginia Polytechnic Institute 

and State University; 1982. 17 pp. 
GROWTH AND YIELD OF SWEETGUMCHERRYBARK OAK MIXTIIRES " 

(ABSTRACT) 

Thomas G. Matney, John D, Hodges, and Alfred n. Sull ivanz 

Sweetgum-cherrybark oak mixtures are widely di stri huted on the minor 

stream bottoms of Mississippi and Alabama, and it is one of the most 

important hardwood types found in these states. This paper describes 

a compatible growth and yield model developed to aid foresters 

involved in the management of these stands. The model uses mixtures 

of diameter distributions, compatible with each stand component's mean 

and quadratic mean diameters. Subsequent merchantable board feet and 

cubic foot volumes are derived by grade using grade distribution 

tables and merchantable height predictors. 

?aper presented at Fourth Bi enni a1 Southern 

Si Tviculdural Research Conference, Atlanta, Georgia, 

November 4-6, 1986, 

"~ississi~~i State University, Mississippi 

State, MS 
A NEW AND SIMPLE METHOD FOR MODELING 

STAND AND STOCK TABLESI/ 

2 1 Bruce E. Borders and Ray A, SouterAbstract.--A simple method for characterizing stand 

and stock tables is presented which does not rely on 

pre-defined mathematical probability distributions. A 

set of percentile points is used to characterize the 

distribution of interest. By assuming a uniform 

distribution of tree frequency between adjacent 

percentile points and using linear interpolation, whole 

stand measures of surviving treeslacre, total 

volumelacre, and merchantable volume/acre can be 

proportioned among any desired diameter size classes. 

TI% flexibility of the method is such that any 

distribution shape can be reproduced (e.g. reverse-j, 

mound-shaped, and multi-modal distributions). This 

simple and flexible method was found to fit observed 

stand and stock tables extremely well for thinned 

natural loblolly pine stands and thus it holds great 

promise for future modeling efforts. 

INTRODUCTION 

Traditional diameter distribution models 

make use of statistical probability density 

functions (pdf) to reproduce stand tables. The 

exponential pdf has been used to model 

uneven-aged stands (Meyer and Stevenson, 1943; 

Meyer, 1952; Schmelz and Lindsey, 1965). Many 

pdf's, including the log-normal, normal, gamma, 

beta, Johnson's Sb, and weibull have been used to 

model unimodal mound shaped distributions 

characteristic of even-aged stands. There are no 

underlying biological precepts that indicate why 

one pdf should be preferred to another. The 

weibull has come to be the pdf of choice due to 

its high degree of shape flexibility and closed 

form cumulative distribution function (Bailey and 

, Dell, 1973). 

A limitation of using pdf's to model stand 

tables is that they are all unimodal. Several 

studies have shown that these unimodal pdf's are 

not always adequate for modeling stand tables 

(Murphy and Farrar, 1981; Cao and Burkhart, 

1984). Below, we present a method for modeling 

stand tables that does not require a predefined 

pdf. This method, referred to as the percentile 

method, is very simple and very flexible (i.e, it 

L1paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

can be used to reproduce reverse-j shaped stand 

tables, as well as unimodal and multimodal 

stand tables), In addition to reproducing 

stand tables, we show how, with slight 

modification, the percentile method can be used 

to partition a per-acre estimate of volume 

directly into size classes without first 

obtaining a stand table. 

STAND TABLES 

Assume we have a egr-acre stand table with 

N trees. Define the i size class with a 

lower diameter at breast height (dbh) limit of 

D and an upper dbh limit of DU.. Then if 

there are Ni trees uniformly dishibuted in 

each of k slze classes (i.e. i=1,2, ..., k) we 

can define an empirical pdf (epdf) 

Ni/N/(DUi - DLi) DLi < D < DUi £0)) = { (1) 

0 elsewhere 

where, 

D - diameter at breast height (dbh), 

N = number of trees per acre, 

Ni = n~gber of trees per acre in the 

i size class, 

DUi = upper dbh limit in the i t h 

size class, 

DLi = lower dbh limit in the i th 

size class. 

Z1~ssistant Professor at the University of Note that the size classes can be of any width 

Georgia in Athens, Georgia and Mathematical (i.e. one-inch, two-inch, product classes, 

Statistician at the USFS Pacific Northwest Forest etc.. .). 

Experiment Station in Portland, Oregon, 

respectively. 
The jth dbh percentile, say P., of this epdf 

for which a tree has dbh less'than P. with 

probability t is J 

j 

P 

j 

F(P ) = I f(D)dD = t (2) 

j -- j 

When the percentile P, occurs in the kth size 

class, P, is calculatJd as 3 

k- 1 

p = (tj- "(Ni/N) (DUk-DLk) (N/Nk) + DLk (3) j i= 1 

where, 

all symbols are as defined above. 

Using equation 3 we can calculate several 

percentiles across the range of dbh values in 

the observed stand table. Once we have 

obtained these percentiles, we can closely 

reproduce the stand table from which the 

percentiles were calculated. We simply assume 

that trees are uniformly distributed between 

adjacent percentiles. This defines a density 

function and associated cumulative 

distribution function similar to equations 1 

and 2. With this cumulative distribution 

function we obtain the following formula for 

calculating Nk, the number of trees per acre 

in size class k 

- t.] [DUk - Pjl/[Pj+l - Pi] +ftj+l 

+ [tj - tilM (4) 

where, 

and all else is as defined above. 

Equation 4 will not reproduce the observed 

stand table exactly, the method tends to even 

out differences between consecutive size 

classes. However, if all size class limits 

were percentiles of the system, then an exact 

reproduction would occur. 

Thus, we have defined a method which can 

reproduce any stand table given a set of dbh 

percentiles from that stand table. For 

modeling purposes we must be able to predict 

these percentiles from stand characteristics. 

A system of percentile prediction equations 

can be formulated using the following 

construct 

PD = £(stand characteristics) 

PD+i = f(PD, stand characteristics) 

where, 

i = -j9 -j+l,,..9-l,l,2,...,1 

PD = percentile selected to "drivet' 

the prediction system; generally 

the percentile that can be 

predicted with the highest 

confidence, 

PD+i = other percentiles of the system, 

which due to constraints, are 

directly or indirectly related 

to P such that there are j D percentiles less than PD and I 

percentiles greater than P D ' 

The individual equations are constructed so 

that percentile estimates are monotonic 

increasing with P . the minimum and P the D+l maximum. Souter 9~386) developed a percentile 

fha se~~of 12 percentiles 

,..., 95 ,100 ) for natural 

stands of thinned loblolly pine using construct 

5. He then used this prediction system and 

equation 4 to reproduce the observed stand 

tables. He found that the percentile method 

performed very well on these unimodal and 

irregularly shaped multi-modal stand tables. 

STOCK TABLES 

It is possible to obtain a predicted stock 

table using a stand table obtained with the 

percentile method as described above. We 

simply use a height-diameter function and a 

volume equation to obtain the volume of the 

average tree in each size class and multiply 

this volume by the number of trees in each size 

class (i.e. using traditional diameter 

distribution modeling methodology). This 

approach is sound and can be used without 

apprehension. However, we would like to 

present an alternative method below. 

Individual tree volume can be thought of 

as being proportional to dbh squared times 

height, Within a dbh size class, height can be 

taken to be proportional to dbh. Thus we can 

say that within a size class tree volume is 

proportional to dbh cubed, with a different 

proportionality constant for each size class. 

Symbolically we write 

where, 

V = tree volume (merchantable 

or total), 

D = dbh, 

H = total tree height, 
kl, k2, k are proportionality 3 constants. 

Now, if we assume that volume is proportional 

to dbh cubed and that trees are uniformly 

distributed within a size class, we can define 

the following empirical pdf for per-acre volume 

3 4 4 

4 Vi D /(DUi - DLi ) /V DLi<D<DUi 

f (D) = I (6) 

0 elsewhere 

where, 

i = 1,2,,..,k, 

= volume in the ith size class, '4 = per-acre volume, 

D = dbh, 

DUi = upper dbh limit in the ith size 

class, 

DLi = lower dbh limit in the ith size 

class. 

The epdf can be used to calculate percentiles, 

P., such that t. percent of the volume in the 

stock table falgs below dbh value P.. These 

percentiles are calculated in a simhar fashion 

tghthose for stand tables. When P. falls in the 

k size class, it is defined as 

where, 

all symbols are as defined above. 

Thus, we can define a set of percentiles for a 

stock table using equation 7. Now if we 

assume that trees are uniformly distributed 

between adjacent percentiles we can define an 

epdf, similar to 6, along with its associated 

cumulative distributiefi function. Using this 

epdf, volume in the k size class is defined 

as 

where, 

and all else is as defined above. 

Just as with stand tables, we must 

develop a prediction system for volume 

percentiles defined in equation 7. This is 

accomplished using construct 5. Souter (1986) 

fit a percentile prediction ~R~~EP~:,, a set 

oft&2 vol me percentiles (0 , , tt: * . . Y 

95 ,100 ) for natural stands of loblolly 

pine. He used the percentile method to 

predict the unimodal and multimodal stock 

tables. He found that the fits were very 

good. 

DISCCSSLON 

The percentile method can be used for 

modeling both stand and stock tables. The 

method is simple to apply and has great shape 

flexibility. Xt can be used in place of 

probability density functions, such as the 

weibull, in traditional diameter distribution 

models. In this instance, the shape 

flexibility (i.e. the ability to reproduce 

reverse-j, unimodal, and multimodal stand 

tables) is a great advantage over pdf models. 

We have shown how it is possible to use 

the percentile method to obtain a stock table 

without first estimating a stand table. We 

simply break a per-acre estimate of volume into 

dbh size classes. Fit statistics with 

empirical data show that this method can be 

used with confidence when only the stock table 

is of interest. 

LITERATURE CITED 

Bailey, R. L., and T. R. Dell. 1973. 

Quantifying diameter distributions with 

the WeibuPl function. Forest Sci 

19:97-104. 

Cao, Q. V., and H. E. Burkhart. 1984. A 

segmented distribution approach for 

modeling diameter frequency data. Forest 

Sci 30:129-137. 

Meyer, H. A. 1952. Structure, growth, and 

drain in balanced uneven-aged forests. J 

Forestry 50:85-92. 

Meyer, H. A., and D. D. Stevenson. 1943. The 

structure and growth of virgin 

beech-birch-maple-hemlock forests in 

northern Pennsylvania. J Agric Res 

67:465-484. 

Murphy, P. A., and R. M. Farrar. 1981. A test 

of the exponential distribution for stand 

structure definition in uneven-aged 

loblolly-shortleaf pine stands. USDA For 

Serv Res Pap SO-164. South For Exp Stn, 

New Orleans, La. 4 p. 

Schmelz, D. V., and A. A. Lindsey. 1965. 

Size-class structure of old-growth forests 

in Indiana. Forest Sci 11:258-264. 

Souter, R. A. 1986. Dynamic stand structure 

in thinned stands of naturally-regenerated 

loblolly pine in the Georgia Piedmont. 

Unpublished Ph.D. Thesis. University of 

Georgia. School of Forest Resources. 

Athens, GA. 166 p. 
Robert M. Farrar, Jr. and Paul A. ~ur~h~g~ 

Abstract. - The Schumacher stand volume function is 

commonly fitted to predict stand volumes in studies of 

growth and yield in natural stands of southern pine, and it 

usually works very well for cubic-foot volumes. However, 

it usually does not perform as well for board-foot volumes, 

particularly for those by the Doyle log rule, This paper 

presents a recent history of developments in stand-level 

volume and volume growth modeling, including use of the 

Schumacher function, and the results of attempts to improve 

this function for Doyle board-foot predictions. 

INTRODUCTION 

Stand-level models for growth and yield 

prediction produce lump-sum or aggregated 

estimates of stand production in terms of basal 

area and volume. Compared to diameterdistribution or individual-tree models, they 

produce less detail but are entirely adequate for 

many purposes. At an elementary level, management 

regimes can be simulated by reference to prepared 

tables or the functions can be entered into a 

programmable calculator, They also run very 

efficiently on microcomputers in either 

electronic spreadsheets or custom application 

programs. Stand-level models usually operate on 

the input stand variables age (or elapsed time), 

site index, and basal area, They commonly 

consist of two principal components: (1) basal 

area driver(s) that project a current basal area 

to a future value and (2) stand volume 

function(s) that convert stand age, site index, 

and basal area into stand volume by utilizing 

either current or future values of these input 

variables. 

RECENT HISTORY OF DEVELOPMENTS 

To best understand where we are in standlevel modeling, we can review its recent history 

to see how current formulation of the components 

of a stand-level system came about. 

L/ Paper presented at Fourth Biennial Southern 

Silvicuf tural Research Conference, Atlanta, 

Georgia, November 4-6, 1986. 

21 Principal Mensurationists, Forestry Sciences 

Laboratory, Monticello, AR, Southern Forest 

Experiment Station, U. S. Department of 

Agriculture, Forest Service, in cooperation with 

the Department of Forest Resources and Arkansas 

Agricultural Experiment Station, University of 

Arkansas at Monticello. 

The first major development after normal 

yield tables was the variable-density yield 

prediction system of MacKinney ad Chaiken 

(1939), in which stand volume is not only a 

function of age and site index but also of 

varying stand density. They used a modification 

of the "Schumacher yield function," a form first 

suggested by Schumacher (19391, and applied it to 

predict stand volume for second-growth loblolly 

pine, The authors of this paper prefer the term 

"stand volume function,'! because yield implies 

not only the standing volume but also the volume 

harvested from a stand up to that time. The 

current common formulation of this function is: 

In = natural or base e logarithm, 

V = stand volume per acre (cubic feet or 

board feet ) , 

bi = parameters to be estimated, 

S = site index (feet), 

A = stand age ears), 

B = basal area per acre (square feet), and 

It is commonly fitted to stand volumes at 

both the start and end of growth periods so that 

volumes can be estimated at any point in time. 

Both cubic- and board-foot volumes are estimated 

with this formulation. 

The next major development was a system of 

compatible growth and yield (stand volume) models 

developed by Clutter (1963) for thinned natural 

loblolly pine in the Southeast. Clutter reasoned 

that a stand volume function should be compatible 
with a volume (growth function and tha-t its 

derivative should produce a volume growth 

function. Conversely, the growth function 

integral should be the stand volume function, In 

his sysdem, Clutter used the above Schumacher 

function to predict current total cubic-foot 

stand volume and developed a volume projection 

function, which incorporated a basal area 

projector, tct predict future stand volume. This 

basic approach has been used since then in some 

form for most stand-level modeling efforts. The 

system provided the first comprehensive system by 

which the growth and production could be 

simulated for thinned (or unthinned) stands for 

various periods, density regimes, and rotations. 

However, growth for a period estimated by the 

volume projection function did not exactly match 

growth obtained by the difference between the 

stand volume function at the start and end of the 

period. This problem was solved by Sullivan and 

Clutter (1972) in their simultaneous stand growth 

and volume prediction system, although the volume 

estimates were still in terms of only total cubic 

feet. 

The first application of the simultaneous 

system that presented a sawtimber predictor in 

addition to a cubic-foot volume predictor was the 

system by Brender and Clutter (1970) for thinned 

natural loblolly pine in the Georgia Piedmont. 

Here the Schumacher functfon was employed to 

provide stand volume equations in terms of stand 

age, site index, and merchantable basal area for 

both merchantable cubic-foot and International 

1/4-inch board-foot volumes. Future stand volumes 

were estimated via basal area projectors 

(drivers) incorporated fnto volume projection 

equations. 

This simultaneous system produces reasonable 

estimates of sawtimber volume and growth. But 

because both the merchantable and sawtimber 

volume predictors employ only merchantable basal 

area, there is no opportunity to manipulate the 

'sawtimber basal area and sawtimber volumes in 

thinning simulations, Therefore, for any age and 

site index, the merchantable basal area dictates 

one sawtimber volume; yet, depending on stand 

history, there could be a number of sawtimber 

basal areas and volumes for a given merchantable 

basal area (more about this later). Also, there 

is no control over the sawtimber cuts in thinning 

regime simulations. One can specify desirable 

residual merchantable basal areas and obtain 

resulting operable cubic-foot volume cuts, but 

the attendant estimates of board-foot cut may or 

may not be operable. Also, the sawtimber volume 

estimates are '3mbeddedw in the merchantable 

volume estimates which cannot be separated into 

estimates of sawtimber and sub-sawtimber 

(pulpwood). 

Other approaches using simultaneous-type 

systems'with single total or merchantable basal 

area drivers have attempted to produce estimates 

of sawti mber volumes and growth in addition to 

total and/or merchantable cubic-foot values. 

Bennett (1970, 1980) employed the Schumacher 

function to estimate merchantable cubic-foot 

stand volumes but used another function employing 

merchantable basal area and cubic-foot volume to 

estimate international 114-inch board-foot 

volumes for thinned even-aged natural slash pine 

stands in the Southeast. Farrar (1979) also used 

the Schumacher function to predict total cubicfoot volumes for stands of thinned even-aged 

natural longleaf pine in the East Gulf area but 

employed ratio estimators to predict a series of 

merchantable and sawtimber volume values from 

total cubic-foot volume, We first fitted a series 

of Schumacher stand volume functions, but some 

intersected and produced anomalous results, We 

could see no ready way to constrain various 

volume estimates to be separate other than to use 

ratio estimators. 

Bennett's system suffered from the same 

problem as the Brender and Clutter system with an 

additional quirk -- often at young ages, slightly 

more sawtimber volume would be predicted in the 

residual stand after a simulated cut than was 

predicted to be present in the stand before the 

cut. This is an artifact of the equation used to 

predict the sawtimber volumes. This function 

apparently does a good job of predicting the 

sawtimber volume for the static conditions of a 

given stand age, site index, and merchantable 

density but can produce such anomalous results 

when put into a simulated thinning regime 

context. The problem occurs at young ages, is 

usually minor, and disappears as age increases, 

It can be practically handled by ignoring it, but 

in fact it is a deficiency in formulation. 

The ratio-estimator stand-volume equation 

system of Farrar (1979) for natural longleaf pine 

was also driven by a single basal area predictor. 

It did provide estimates of total, merchantable, 

and sawtimber volumes that allowed, by 

subtraction, estimates of nonmerchantable, 

pulpwood, and sawtimber volumes and growth. 

However, it also had the problem of anomalous 

predictions for sawtimber cuts at young ages. 

Again, this minor problem disappeared with 

increasing age but remained a formulation 

deficiency. 

Thus, to successfully and lcgieall y predict 

the stand volume components of interest in a 

system that would provide for manipulation of the 

density components and produce logical results in 

thinning simulations, some new formulations ware 

needed. The simultaneous-type systems seemed to 

be the best basic approach because they appeared 

to work well for total or merchantable stand 

volumes and growth. Such a system consists of 

two principal parts: (1) the stand volume 

function and (2) the basal area driver. Both 

parts were inspected for opportunities for 

improvement, 

The Schumacher stand volume model appeared to 

be adequate, No obvious way to improve it could 

be determined other than to possibly have a 

function for merchantable cubic-foot volume that 
Table 1.--Evaluation of a Schumacher function for Doyle volume fitted 

with different basal area variables, natural loblolly pine 

Criterion 

Variable nl/ 721 

Merch. 

basal 268 3707 -76 -27 161 6 36 141 

area 

Sawt. 

basal 268 3707 .86 -25 1232 7 40 

area 

11 n = number of observations. 

- 21 = mean observed Doyle stand volume per acre. 

F.I. = Fit Index 

- 41 d = mean deviation = l/n x(?i-yi). 

51 RMSd = root mean squared deviation 

61 = mean percent deviation = 11n ~[(~i-Yi)/Yi] (100). 

11 RMS%d = root mean squared percent deviation 

h 

where yi = observed value and yi = predicted value. 

would employ merchantable basal area as an 

independent variable and a function for sawtimber 

volume that would employ sawtimber basal area. It 

seemed that the sawtimber volume should be better 

related to sawtimber basal area than to 

merchantable basal area, and this was verified. 

Table 1 shows the results of fitting the 

Schumacher function to a natural loblolly pine 

data set of Doyle stand volumes by alternatively 

using each measure of basal area as an 

independent variable, 

The next step was to modify the basal area 

driver to capitalize on this information. To use 

separate measures of basal area in the separate 

stand volume functions, it seemed that two 

separate but interrelated drivers were needed -- one for merchantable basal area and one for 

sawtimber basal area. If successful, this might 

result in a merchantable stand volume function 

(cubic feet) coupled with a merchantable basal 

area driver and also a sawtimber stand volume 

function (cubic feet or board feet) coupled with 

a sawtimber basal area driver in a consistent 

system to predict volumes and growth for both the 

merchantable stand and the sawtimber portion of 

the stand. 

In a first attempt to develop such a dual 

system, Murphy and Farrar (1982) worked with a 

data set from uneven-aged loblolly/shortleaf pine 

stands on nominal site index 90 in the West Gulf 

area and employed the simultaneous-type models of 

Moser and Hall (1969) as a basis. First, the 

authors developed a merchantable basal area 

driver and a merchantable cubic-foot stand volume 

equation. Then a sawtimber basal area biver, 

which was constrained to be equal to or less than 

the merchantable basal area driver, was developed 

along with sawtimber stand volume equations for 

cubic feet and board feet by the Doyle, 

International 114-inch, and Scribner log rules 

(~urphy and Farrar 1983, Farrar and others 1984). 

This system worked well and had none of the 

problems associated with the previous attempts to 

predict merchantable and sawtimber volumes and 

growth, It worked so well that it was extended 

to prediction systems for natural even-aged 

stands of shortleaf pine in the West Gulf (~urphy 

and Beltz 1981, Murphy 1982), loblolly pine in 

the West Gulf (Murphy 1983a, 1983b), and longleaf 

pine in the East Gulf (~arrar 1985). It was 

again re-employed for uneven-aged stands of 

shortleaf pine in the West Gulf (Murphy and 

Farrar 1985). 
These systems permit simulations of thinning 

regimes in which the merchantable (or total) 

basal area and the sawtimber basal area can be 

manipulated independently under the logical 

constraint that the sawtimber is always a subset 

of the merchantable (or total) basal area, In 

other words, the sawtimber basal area must always 

be less than or equal to the merchantable basal 

area. The basal area drivers were formulated and 

fitted under this constraint, but there is no 

mechanism to prevent their being misapplied. For 

example, in a thinning regime simulation, there 

is nothing to prevent the user from erroneously 

specifying a cut of 10 square feet of 

merchantable basal area and 20 square feet of 

sawtimber basal area. The user must remember 

that the sawtimber stand is contained within the 

merchantable stand and avoid such illogical 

specifications. 

Properly applied, these systems produce 

considerable detail on volume production, even 

though they are stand-level systems. They 

typically permit estimates of current and future 

merchantable cubic-foot volumes, sawtimber cubicfoot volumes, and board-foot volumes via one or 

more log rules. A future volume minus a current 

volume produces an estimate of growth. Pulpwood 

volume, current or future, can be obtained by 

subtracting a sawtimber cubic-foot volume from a 

corresponding merchantable cubic-foot volume, and 

growth is again estimated as the future pulpwood 

volume minus the current pulpwood volume. 

REFINEMENT ATTEPlPTS 

So, with this considerable amount of detail 

possible in our stand-level systems, what could 

be improved? The authors thought it possible to 

improve upon the estimates of stand board-foot 

volumes by the Doyle rule. Typically, board-foot 

fits of the Schumacher stand volume function are 

best for the International 114-inch rule, second 

best for the Scribner rule, and third best for 

the Doyle rule (table 2). But the Doyle rule, 

Table 2.--Evaluation of Schumacher function 

fitted to sawtimber stand volumes by three log 

rules, natural loblolly pine ................................................... - Criterion 

Log rule n y ................................. - 

F.1, d RMSd RNSSd ................................................... 

due to its common usage, is usually of the most 

interest. Relative to the other two rules, the 

Doyle rule underestimates the board-foot volumes 

of small trees, and the underestimates decrease 

as tree size increases. Therefore, it appeared 

that this disparity probably caused increased 

variability in Doyle volume observations and that 

it might be possible to improve the Doyle volume 

estimates via the Schumacher function by (a) 

adding new variables or (b) adding interactions 

of the basic three variables to account for more 

of the variation, However, attempts to do this 

were not successful. 

Typically, when one fits the Schumacher 

function to Doyle stand volume data, basal Erea 

accounts for the most variation, age is next most 

important, and site index is least important. 

For example, table 3 shows the results of adding 

variables to a model in the above sequence using 

268 observations on Doyle stand volume in evenaged stands of natural loblolly pine. One can 

see that the sawtimber basal area (~(Bs)) 

accounted for about 72 percent of the variation; 

including age (I/A) added about 12 percent, and 

including site index (s) with age and sawtimber 

basal area added about 2 percent for a total of 

about 86 percent. 

It seemed that information on merchantable 

basal area (BPI) in addition to sawtimber basal 

area might improve the Doyle stand volume 

function fit. Therefore, the authors1 first 

attempts to improve the Schumacher function were 

to add single variables such as ~(BM), 

I~(BM/BS), or I~(BH)/A to the model. These did 

improve the Fit Index a few percentage points and 

the resulting equations appeared logical when 

they were evaluated alone, but when they were 

inserted into software to evaluate thinning 

regimes, illogical results were obtained that 

were similar to those encountered in the Bennett 

(1970, 1980) slash pine system and the Farrar 

(1979) longleaf pine system -- at young ages an 

after-cut stand could have more predicted 

sawtimber volume than was predicted for the 

Table 3.--Evaluation of constructing a Schumacher 

functlon for Doyle volume by sequentially 

inciuding independent variables accounting for 

the most variation, natural loblolly pine 

................................................. 

- Criterion 

Variable n y ................................ - F,I, d %IISd % MS$d ................................................. Doyle 268 3707 .86 -25 1232 7 40 

Scrib- 268 5559 .93 -33 1173 2 25 

ner 

Inter- 268 6547 .94 -77 -1202 1 22 

national 

1 /&inch 
before-cut stand, even though no sawtimber cut 

was simulated, because the BM was altered by the 

simulated cutting. Therefore, predictions can be 

similarly anomalous if any variable is included 

in a sawtimber stand volume function that can be 

altered in a simulated thinning, even though the 

sawtimber basal area is unaffected. Thus, it was 

apparent that any new variables would have to be 

restricted to some combination of site index, 

age, and sawtimber basal area if logical results 

in thinning applications were to be obtained. 

Therefore, we next investigated the addition 

of possible interactions of S, I/A, and In(BS) to 

the Schumacher function. These possible 

interactions are S/A, (s)~~(Bs), I~(Bs)/A, and 

(s/A)~~(Bs). Using the above loblolly data set, 

an "all possible combination" screening of 

regressions from the single-variable through the 

full seven-variable model was performed, and 

those equations having "goodness of fit" that 

showed any promise of improved predictions were 

evaluated. The "goodness of fit" criteria were 

Fit Index, mean deviation, mean percent 

deviation, root mean squared deviation, and root 

mean squared percent deviation, as defined in the 

footnotes to table 1. Some 60 regressions were 

evaluated alone and in a thinning simulation 

context, but we were not able to improve on the 

basic three-variable Schumacher function to 

predict Doyle stand volumes. Again, some 

regressions improved the Fit Index a few 

percentage points and otherwise showed improved 

fit, but when inserted into thinning simulation 

software these regressions either did not alter 

the predictions appreciably or, if they did, a 

new anomaly occurred -- the (~oyle/BS) ratio 

would decline at older ages rather than logically 

continue to increase. 

CONCLUSION 

During the past quarter-century considerable 

progress has been made in stand-level modeling of 

volume and volume growth in thinned natural 

southern pine stands, Simultaneous-type standlevel volume and volume growth prediction systems 

are presently available for even-aged natural 

stands of the four major southern pines and for 

two uneven-aged pine types. These systems 

typically consist of one or two basal area 

drivers to project future basal areas and several 

stand volume functions that utilize basal area 

and other stand information to predict current 

and future volumes. They are also relatively 

simple, easy to implement on microcomputers, and 

valuable as a quick means to estimate expected 

volumes and growth for a wide variety of stand 

conditions, growth periods, thinning regimes, and 

rotation lengths. The amount of detail 

obtainable on volume and growth components is 

surprising. When inserted into relatively simple 

simulation software, these systems provide the 

capability of comparing a variety of "what if?" 

scenarios, 

When utilizing the Sch~~macber stand volume 

function in such systems, it appears that once 

the main effects of stand basal area, age, and 

site index are accounted for, t, ere would be 

little practical gain in trying to add other 

variables to improve the fit. This seems 

particularly true if logical results are to be 

expected in thinning simulations. There is still 

some debate over the long-term trends of the 

basal area development models, but they appear to 

be adequate for short periods or situations where 

repeated thinnings at short intervals are 

simulated. The associated stand-volume 

functions, in their present form, are probably 

essentially complete in their development, but 

the ultimate in this area of development has not 

necessarily been reached. Recent work by Amateis 

and others (1986) presents a stand-level volumeratio model that portions total stand volume to 

any desired top diameter and/or threshold d,b.h. 

limit coupled with a model that distributes the 

total number of trees by d.b.h. class, If 

supplemented with a suitable survival function 

and basal area driver, this promises to afford an 

easily implemented stand volume and growth 

predictor that will allow product-volume detail 

comparable to that of d.b.h.-distribution 

predictors. 

If detail on the size-class distribution of 

stems or volumes by product categories is 

desired, resorting to something similar or to 

diameter-distribution or individual-tree 

approaches in modeling is probably the best 

course. This is not to say that stand-level 

models similar to current forms will soon become 

extinct. Their aggregated estimates are entirely 

adequate for many purposes, and they will 

probably remain useful as compatible concomitants 

for diameter-distribution and individual-tree 

systems in which the user selects the set of 

predictors according to the detail desired. 

LITERATURE CITED 

Amateis, Ralph L.; Burkhart, Harold E.; Burk, 

Thomas E. A ratio approach to predicting 

merchantable yields of unthinned loblokly pine 

plantations. Forest Science. 32:287-296; 1986. 

Bennett, Frank A, Variable-density yield tables 

for managed stands of natural slash pine. Res, 

Note SE-141, Asheville, HC: U.S. Department of 

Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1970. 7 p, 

Bennett, Frank A. Growth and yield in natural 

stands of slash pine and suggested management 

alternatives. Res. Pap. SE-211, Asheville, MC: 

U,S. Department of Agriculture, Forest Service, 

Southeastern Forest Experiment Station; 1980. 

8 P* 
Brender, E.V.; Clutter, Jerome L. Yield of evenaged, natural stands of loblolly pine. Report 

23, Macon, GA: Georgia Forest Research Council; 

1970. 7 p* 

Clutter, Jerome L, Compatible growth and yield 

models for loblolly pine. Forest Science. 

92354-371; 1963. 

Farrar, Robert M,, Jr. Growth and yield 

predictions for thinned stands of even-aged 

natural longleaf pine. Res. Pap. SO-156. New 

Orleans, LA: U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1979. 78 p. 

Farrar, Robert M., Jr, Volume and growth predictions for thinned even-aged natural longleaf 

pine stands in the East Gulf area. Res. Pap, 

SO-220. New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 4985. 171 p. 

Farrar, Robert M., Jr.; Murphy, Paul A.; Willett, 

R, Larry. Tables for estimating growth and 

yield of uneven-aged stands of loblollyshortleaf pine on average sites in the West 

Gulf area. Bulletin 874. Fayetteville, AR: 

University of Arkansas, Division of 

Agriculture, Arkansas Agricultural Experiment 

Station; 1984. 21 p. 

MacKinney, A.L,; Chaiken, L.E. Volume, yield and 

growth of loblolly pine in the mid-Atlantic 

coastal region. Tech. Note 33. Asheville, NC: 

U.S. Department of Aqiculture, Forest Service, 

Appalachian Forest Experiment Station; 1939. 

30 P* 

Moser, J.W., Jr.; Hall, O.F. Deriving growth and 

yield functions for uneven-aged forest stands. 

Forest Science. 15:183-188; 1969. 

flurphy, Paul A, Sawtimber growth and yield for 

natural, even-aged stands of shortleaf pine in 

the West Gulf. Res. Pap, SO-181. New Orleans, 

LA: U.S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1982. 13 p. 

Murphy, Paul A. A nonlinear timber yield 

equation system for loblolly pine. Forest 

Science. 29:582-591; 1983a. 

Murphy, Paul A, Merchantable and sawtimber 

volumes for natural even-aged stands of 

loblolly pine in the West Gulf region. Res. 

Pap. SO-194. New Orleans, LA: U.S. Department 

of Agriculture, Forest Service, Southern Forest 

Experiment Station; 1983b. 38 p. 

Murphy, Paul A*; Beltz, Roy C. Growth and yield 

of sh~rtleaf pine in the West Gulf region. Res. 

Pap. SO-169. Mew Orleans, LA: U.S. Department 

of Agriculture, Forest Service, Southern Forest 

Experiment Station; 1981. 15 p. 

Murphy, Paul A,; Farrar, Robert M. Interim 

models for basal area and volume projection of 

uneven-aged loblolly-shortleaf pine stands. 

Southern Journal of Applied Forestry. 6:115- 

119; 1982. 

Murphy, Paul A,; Farrar, Robert M., Jr. 

Sawtimber volume predictions for uneven-aged 

loblolly-shortleaf pine stands on average 

sites. Southern Journal of Applied Forestry. 

7:45-50; 1983. 

Murphy, Paul A,; Farrar, Robert M., Jr. Growth 

and yield of uneven-aged shortleaf pine stands 

in the Interior Highlands. Res. Pap. 30-218. 

New Orleans, LA: U,S. Department of 

Agriculture, Forest Service, Southern Forest 

Experiment Station; 1985. 11 p. 

Schumacher, F.X. A new growth curve and its 

application to timber-yield studies. Journal 

of Forestry. 37:819-820; 1939. 

Sullivan, Alfred D.; Clutter, Jerome L. A 

simultaneous growth and yield model for 

loblolly pine. Forest Science. 18:76-86; 1972. 
RECOVERING DIAEIETm DISTRIBUTIONS FROM 

CHER AND COILE'S MODEL FOR 

NATURAL EVEN-AGED LOBLOLLY PINE STANDS 

21 Quang V. Cao - 

Abstract.--Schumacher and Coile's (1960) whole stand models 

for several southern pine species do not provide growth and 

yield information at the size-class level. This paper presents 

two methods of deriving a diameter distribution from Schumacher 

and Coile's model for even-aged natural stands of loblolly pine. 

Parameters of a Weibull function that described a diameter 

distribution were recovered such that either the resulting basal 

area (method 1) or volume per acre (method 2) was compatible 

with Schumacher and Coile's value. 

Results indicated that it might not be possible to have 

complete compatibility for both volume and basal area. Method 1 

provided compatible basal area estimates at the expense of 

consistently underestimating total volume per acre by 5 to 18 

percent, as compared to Schumacher and Coile's model. On the 

other hand, method 2 overestimated basal area per acre by 5 to 

19 percent in order to satisfy the volume constraint. 

INTRODUCTION PROCEDURES 

Whole stand models for natural stands of 

loblolly pine include those from Schumacher and 

Coile (1960), Brender and Clutter (1970), 

Burkhart et al. (19721, Sullivan and Clutter 

(1972), and Murphy (1983), to name a few. These 

models are used to predict yield for a stand in 

terms of volume per acre. Size-class 

information was recently provided by Burk and 

Burkhart (19841, who used the Weibull 

probability density function to approximate 

diameter distributions. Data employed in their 

study were previously used by Burkhart et al. 

(1972). 

Forest managers who are currently using 

Schumaeher and Coile's (1960) model for loblolly 

pine natural stands might need additional 

information on the distribution of trees and 

volume by size class. The objective of this 

study was to derive the parameters of a Weibull 

diameter distribution from Schumacher and 

Coile's model for even-aged natural stands of 

loblolly pine. 

The Weibull probability density function 

used in describing diameter distributions has 

the following form: 

f(x) = (c/b) I (x-a)/blc-I exp {-[(x-a)/bjc], 

where x = diameter random variable, 

a = location parameter, 

b = scale parameter, and 

c = shape parameter. 

The location parameter (a) and the average 

stand diameter (6) were predicted from 

regression equations developed by Burk and 

Burkhart (1984). Table 1 presents these two 

equations along with Schumacher and Coile's 

( 1960) equations for yield prediction. The 

other Weibull parameters (b and c) were obtained 

(or recovered) using the following methods. 

Method 1 

The average diameter and basal area per 

- 1/ Paper presented at Southern Silvi- acre, computed from the Weibull diameter 

cultural Research Conference, Atlanta, Georgia, distribution, were constrained to be identical 

November 4-6, 1986. to those from regression equations. This method 

21 Associate Professor of Forestry, School involved solving for the Weibull parameters b 

of ~orestr~, Wildlife, and Fisheries, Louisiana and c from the following system of equations: 

Agricultural Experiment Station, Louisiana State 

University Agricultural Center, Baton Rouge, LA 

70803. 
Table 1. --Equations from Burk and Burkhart (1984) and Schumacher and Coile (1960) that form a whole stand 

mode1 for natural stands of loblolly pine. 

Equation 

Number Variable a / Equation - 

---------------- Burk and Burkhart (1984) - - - - - - - - - - - - - - - 

1 Weibull location parameter a = maximum (0.0, -3.6732 + 0.01111 B + 0,6876 nq) 

2 Arithmetic mean diameter ln(Dq - 6) = 32.9856 - 4.7745 In (H) - 326.14811~ 

- 1.7136 ln(B) - 109.56311~ 

---------------- Schumacher and Coile (1960) - - - - - - - - - - - - - - - 

3 Individual tree volume = 0.0817 Di + (H/100) (0.4237 - 0.64042 Di + 0.227872 DZ) 

4 Dominant height log(^) = log (SI) - 6.528 (1IA - 1/50) 

5 Stocking percent SP = B [0.8409 - 0.001707 H + 10.621A - 0.1408 (H/A)] 

6 Trees per acre log (N) = 4.1218 + 2.68431A - 1.7130 log (H) + 0.6343 log (B) 

7 Average volume per tree log (V/N) = -3.3920 + 1.3321 log (Dq) + 1.7411 log (H) 

a' Notation 

Weibull location parameter, 

Stand age in years, 

Basal area in sq, ft./acre, 

Quadratic mean diameter in inches, 

Average diameter, or arithmetic mean dbh, in inches, 

Average height in feet of the dominants and codominants, 

Diameter at breast height in inches of tree i, 

Total cubic-foot volume inside bark of tree i, 

Total cubic-foot volume inside bark per acre, 

Site index in feet, base age 50 years, 

Stocking percent, 

Trees per acre. 
D - f- = ja x f(x) dx 

and B = KN 1; X~ f(~j dx 

or, in another form: 

and B = KN [a2 + 2a fi + b2r(l + 2/c)] 

where r(,) = the complete gma function, 

R = 0.005454 if diameter is in 

inches and basal area in square 

feet , N = number of trees per acre. 

After all Weibull parameters had been 

obtained, a stand and stock table was generated 

and the resulting total volume per acre was 

evaluated against Schumacher and Coile's yield 

value, 

Method 2 

In this approach, the Weibull parameters b 

and c were recovered such that the diameter 

distribution yielded the same values for average 

stand diameter and total volume per acre as did 

those predicted from regression equations. In 

other words, b and c are solutions of 

D = Jz x f(r) dx 

and V = N +/a v(x) f(xj dx 

or, in another form: 

where B = average height in feet of the 

dominants and codominants, 

V = total cubic-foot volume inside bark 

per acre, 

bi = coefficients from equation (3) of 

Table 1: 

b1 = 0.0817; b3 = -0.64042; 

b2 = 0.4237; b4 = 0.227872. 

This approach ensured that total volume per 

acre computed from the diameter distribution was 

compatible with Schumacher and Coile's predicted 

value. The percent difference between 

Schmacher and Coile's basal area and the 

Weibull-generated basal area per acre was then 

calculated. 

RESULTS AND DISCUSSION 

The evaluation of method 1 is shown in 

Table 2, which presents total volume per acre 

values predicted from Schumacher and Coile's 

whole stand model and those computed from the 

Weibull diameter distribution, for combinations 

of site index, age, and basal area per acre. 

Stand densities used in these combinations were 

predicted from equation (5) of Table 1 for 

"well-stocked" loblolly pine stands. Per acre 

volumes from the Weibull distribution were 

consistently lower by 5 to 18 percent than their 

counterparts predicted from the regression 

equation for a given basal area level. 

The information in Table 3 shows a similar 

trend in basal area for method 2. For a 

specified level of total volume per acre, the 

WeibuLl distribution resulted in an increase of 

5 to 19 percent in basal area value. As an 

example, the Weibull distributions derived from 

both methods are presented in Figure 1 for a 

well-stocked stand of site index 70 feet (base 

age 50) at age 40. 

These results explained the failure of an 

initial attmpt by the author to derive a 

Weibull dimeter distribution such that both 

basal area and volme per acre were compatible 

with Schumacher and Coile's predicted values. 

Either convergence problms were encountered or 

an illogical diameter distribution (reverse 

J-shape curve with a heavy right tail) resulted 

from this attempt. Frazier (1981) also reported 

convergence problems in his similar efforts with 

both the Weibull and beta distributions for 

loblolly pine plantations. 

If a forester chooses to use Schumacher and 

Coile's (1960) whole stand model and desires 

additional information at the size-class 

distribution level, he has to decide between 

using method 1 for compatible basal area per 

acre or method 2 for compatible volume per acre. 

Method 2 is useful for partitioning stand volume 

into different product volumes. 

LITEMTURE CITED 

Brender, 3. V., and J. L. Clutter. 

1970, Yield of even-aged natural stands of 

loblolly pine. Ga. For. Res. Counc., Rep. 

23, 7p. 

Burk, T. E., and H. E. Burkhart. 

1984. Diameter distributions and yields of 

natural stands of loblolly pine. School of 

For. and Wildl. Res., Va. Polytech, Inst. 

and State Univ., FWS-1-84, 46p. 

Burkhart, H. E., R. C. Parker, and R. G. 

Oderwald. 1972. Yields for natural stands of 

loblolly pine. Dive of For. and Wildl. 

Res., Va. Polytech. Inst. and State Univ., 

FWS-2-72, 63p. 

Frazier, J, R. 

1981. Compatible whole-stand and diameter 

distribution models for loblolly pine. 

Ph.D. Thesis, Va. Polytech. Inst. and State 

Univ., L25p. 

Murphy, P. A. 

1983. Merchantable and sawtimber volumes for 

natural even-aged stanas of loblolly pine in 

- the West Gulf region, USDA For. Serv. Res. 

Pap, SO-194, 38p. 

Schumacher, F. X,, and T. S. Coile. 

1960. Growth and yield of natural stands of 

the southern pines. T. S. Coile, Inc., 

Durham, N.C., 115p. 

Sullivan, A. D., and J. L. Clutter. 

1972. A simultaneous growth and yield model 

for loblolly pine. For. Sci. 18:76-86. 
Table 2.--Evaluation of volumes from Schumacher 

and Coile's (1960) regression equation and 

from the Weibull diameter distribution (method 

1) for various combinations of site index 

(base age 50), age, and basal area per acre. 

Table 3.--Evaluation of stand basal areas from 

Schumacher and Coile's (1960) regression 

equation and from the Weibull diameter distribution (method 2) for various combinations of 

site index, age, and volume per acre. 

Site Basal 

a/ k Diff *- cl index Age area V - 

3 ft yrs ft2/ac ft3/ac ft lac 4 

Site Total ib c / indexAge volume Ba/ $i;b' Diff.- 

3 2 2 ft yrs ft/ac ft/ac ftlac 2 

V = Total volume ib (cu.ft. /acre) from 

Schumacher and Coile ( 1960), 

- b/ ? = Total volume ib (cu. ft. /acre) from the 

Weibull diameter distribution, 

B = Basal area (sq. ft. /acre) from Schumacher 

and Coile (1960), 

= Basal area (sq. ft. /acre) from the 

Heibull diameter distribution, f-' C' Difference X = 100 (V - V)/V. 4 C' Difference 4 = 100 (B - B)/B. 

DBH Is Isekee 

Figure 1.--Weibuil distributions derived from 

both methods for a stand of site index 70 at 

age 40. 
TiIE PREDICTION OF DATA INTO MULTIPLE CATEGORIES USING A FORM OF LOGISTIC REGRESSIO~' 

2 1 Bolton, R. K,, R. S. Meldahl, and M. ErikssonAbstract.--A considerable amount of data in forestry is 

grouped i n t o d i s t i n c t classes, ie. dbh classes, crown 

classes, stocking levels, and product classes. A form of 

logistic regression can be used to predict such multiple 

classifications. This technique will be valuable in making 

predictions for many variables used in forestry. Examples 

are presented of predictions made into some of the common 

classifications used in forestry. 

INTRODUCTION 

Much of the data collected in forestry is done 

by placing observations into discrete classes. 

Some common examples of variables collected by a 

classification system are: crown class, tree 

class, log grade, and site class. In some cases, 

such classifications are the only way information 

may be obtained on the variable. Furthermore, 

such forms of categorization can provide a 

forester with a wealth of information, and the 

prediction of observations into such classes can 

be quite useful. However, standard linear 

regression techniques do not provide an adequate 

framework for modeling such class variables. 

The logistic function has been applied 

frequently in forestry to model the probability 

of mortal ity (Hamil ton 1974, Monserud 1976). 

This function may also be used to predict the 

probabilities of an event occurring in several 

categories. This technique has been successfully 

used in the medical field, and is well documented 

in the statistical literature (Anderson 1982, 

Vital ino 1978, Walker and Duncan 1967). 

Furthermore, routines exist in most major 

statistical packages (SAS, BMDP) to fit models 

using the logistic function. 

1/ Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

L' Programmer 111 and Assistant Professor, 

School of Forestry, A1 abama Agricultural 

Experiment Station, Auburn University, AL 36849; 

and Research Assistant, College of Forestry, 

a University of Minnesota. 

LOGISTIC FUNCTION 

The logistic function is most easily understood 

by first examining the case for predicting only 2 

classes (0,1), or what is commonly referred to as 

a dichotomous dependent variable (Walker and 

Duncan 1967). If we define: 

Po = probability of 0 occurring; 

P1 = probabil ity of 1 occurring; 

probability theory then tells us: 

Therefore, by knowing P we also know P . In turn 

only one of these probadilities needs t8 be 

modeled, say P for this example. Using the 

logistic functlon the model for P1 can be defined 

to be; 

where, 

a, B - parameters to be estimated. 

X - predictor variables. 

In derivifig this logistic regression equation, 

only one assumption is required, namely that the 

natural log (In) (P IP ) is linearly related to 

the predictor variafilel, X. As no requirements 
are made on the distribution of X, they may be 

either discrete or continuous (Affi and Clark 

1984). However the estimates of a and $ are 

usually made through maximum likelihood methods, 

thereby requiring ample observations in each 

class to arrive at an accurate estimation. This 

use of the logistic regression equation has 

commonly been used in forestry to predict 

mortality. It may also be used to predict such 

variables as merchantability, disease and/or 

insect infestations, and the probability of 

fire. 

Many variables in forestry are collected by a 

classification system having more than simply 

two levels. Therefore, this simple case of 

predicting a dichotomous variable can not always 

be utilized. If the variable is collected in 

ordered categories, logistic regression can be 

used for their prediction. To explain how such 

predictions are made the case where the response 

variable takes on three ordered values (1,2,3) 

is examined. In this case we will define; 

P1 = probability of 1 occurring; 

Pp = probability of 2 occurring; 

P, = probability of 3 occurring. 

Then from probability theory we know that; 

So that by knowing the quantity (P2 + P ) we 

also know P . As in the dichotomous caze, the 

logistic fuiction is used to define the model 

for (P2 + P3) to be; 

1.0 

P2 + P3 = 

1.0 + e (-a1 -B 

where: 

al$ $ - parameters to be estimated 

X - predictor variables. 

Next, the probability of being in class 1, P1, 

is ignored, and the probability of being in 

class 2 or class 3 is calculated. For these two 

probabilities it is known that; 

Since a model has been constructed for (P + 

P3), only P3 needs to be determined to ge? P2. 

Once again, using the logistic function the model 

for P3 is defined to be: 

where: 

a2, $ - parameters to be estimated 

X - predictor variables. 

This logistic regression equation is also related 

to the equation for the quantity (P2 + P2). It 

is even assumed that the slope parameter B are 

the same in the two models. Once the two models 

have been fit, P and P are then simply 

calculated by suhtractign. 

At this point the probabilities Ply P2 and P3 

can be estimated for any individual. A simple 

assignment scheme, such as selecting the class 

with the greatest probability and assigning that 

to be the prediction of the response variable, 

can be used. Of course, all the previous 

restrictions for the dichotomous dependent 

variable are applicable to this situation. 

Applications requiring further classes would 

simply be extensions of this case. 

DATA AND METHODS 

To illustrate the use of logistic regression, 

examples of predictions for log grade, tree 

class, and crown class are presented. The data 

used in these predictions are for shortleaf ~ine 

(Pinus echinata Mill) from Continuous ore st' 

Inventory (CFI) plots in even aaed stands in the 

piedmont- region of A1 abama. predictor variables 

available for this analysis consisted of tree 

variables, such as dbh, total height, and sawlog 

height, and plot variables such as basal 

areafacre, trees/acre, and site index. 

Calculations were made using the Proc Logist 

routine in the SAS User Supplemental Library 

(Harrell 1986). Variable selection was done by 

plotting the variables and by using a stepwise 

option available in Proc Logist. This selection 

was then augmented by subjective decisions based 

on considerations such as ease of measurement 

and/or faith in the meaningfulness of the 

variable. Once variables were selected, Proc 

Logist was again used to estimate the regression 

coefficients, a and 8. 

To determine how we11 the resultant logistic 

equation fits the data, Proc Logist computes 

several different but related fit statistics. 

The first two statistics are called Model 

Chi-Squares. They are calculated using the 

estimated mode1 parameters, a and B, and are 
approximately distributed as chi-square 

variables. These Chi-Squares values test the 

joint significance of all the variables in the 

equation (Warrell 1986). A large Model 

Chi-Square value, with a corresponding low 

probability or P value, is an indication that the 

variables are useful in the mode1 (Affi and Clark 

1984). The first Model Chi-Square calculated by 

Proc Logist is labeled the Score Statistic. This 

value is calculated before a and 8 are estimated, 

and is only useful if the parameter estimates do 

not converge. If the parameters do converge then 

a Model Likelihood Ratio (L.R.) Chi-Square is 

calculated and labeled the -2 Log L.R. 

Chi-Square. This is also commofly known in the 

statistical literature as the G statistic. Each 

Model Chi-Square is also output with its 

corresponding approximate P value and a statistic 

called R. This R statistic is similar to the 

mu1 tiple correlation coefficient, R-Square, in 

linear regression analysis. An R statistic of 0 

would indicate a poor fit and a value of 1 would 

indicate a perfect relationship. These 

statistics are very useful in determining the 

overall fit of the model. 

Next Proc Logist outputs statistics on the 

intercepts and variables in the model. In each 

case, the coefficient, its standard error, a 

chi-square value, and it's associated P value are 

output. Then for each variable in the model, an 

individual R statistic is calculated. These R 

statistics measure the contribution of that 

variable to the model. An R value of 0 will 

indicate that the variable provides no 

contribution to the model, an R value of 1 

indicates that the variable is perfectly related 

in the positive direction, and an R value of -1 

indicates that the variable is perfectly related 

in the negative direction (Harrell 1986). These 

individual statistics are particularly helpful in 

the selection of variables to be included in the 

model. 

Lastly, four statistics are output which assess 

the predictive ability of the entire model. 

These four statistics are the C, Somer Dyx, 

Gamma, and tau-a. All of these statistics 

attempt to rank the correlation between the 

predicted probabil ities and the observed 

outcomes. In all cases, a value of 0 would 

indicate a poor fit and a value of 1 would 

indicate a perfect fit. *or more information on 

how these values are calculated, please refer to 

Harrell (1986) and/or Goodman and Kruskal (1979). 

All of these statistics may be viewed when 

assessing the model. However, when the model 

contains discrete dependent variables the C or 

Somer Dyx are usually the most meaningful. 

Similarly, if it is desired to compare a model 

which contains mainly continuous variables to a 

model with discrete variables, then tau-a would 

be preferred. Although the Gamma statistic is 

output its use is not highly recommended. 

EXAMPLE 1. LOG GRADES 

Log grade is one of the more common and valuable 

variables collected by means of a classification 

system. The data presented 3 classes of log 

grade: 

Loq Grade Cl ear Faces- 3 / 

1 3-4 

2 1-2 

3 0 

Furthermore, due to the definition of log grade, 

only trees with diameters greater than the 8-inch 

dbh class were considered. Variables selected to 

mode1 log grade were dbh, site index, and sawlog 

height. Table 1 presents the results from Proc 

Logist. The Model Chi-Square indicates that the 

mode1 was significant. The individual Chi-Squares 

also show a good fit. However, the individual R 

statistics do not indicate a very good fit and the 

values for the C and Somer Dyx only indicate a 

moderately we1 1 fit model. Next, a frequency 

table of actual log grade versus predicted log 

grade is presented in Table 2. This table reveals 

that 71% of the time the predicted values were the 

same as the actual value, and that 98% of the time 

the predictions agreed with or were within 1 grade 

of the actual log grade. 

EXAMPLE 2. CROWN CLASSES 

Crown classes are frequently collected to 

describe a stand. In the example data set, five 

crown classes existed: 

0 - Dominant 

1 - Co-dominant 

2 - Intermediate 

3 - Suppressed 

4 - Open Grown 

Due to a lack of observations in crown class 4 and 

because open grown trees in a typical 5tand were 

viewed as occurring very rarely, class 4 was 

dropped from this analysis. The variables 

select89 to model crown class were basal area 

bigger- , dbh, and site index. Table 3 shows the 

regression coefficients and associated statistics 

from Proc Logist. As with the log grade model, 

the crown class model was significant, but only a 

moderate fit was obtained. Table 4 is the 

31 Clear faces are those free of knots 

measuring more than a half inch in diameter, 

overgrown knots of any size, or holes of more than 

a quarter of inch in diameter. 

41 Basal area bigger is defined as the amount of 

basal area1acre of trees greater than or equal to 

the basal area of the current tree. 
Table 1.--Results of the Prediction of Log Grade, 

using Proc Logist. 

144 Observations 

13 Log Grade = 1 

40 Log Grade = 2 

91 Log Grade = 3 

0 Observations deleted due to missing values 

Variable Mean Mi n imum Maximum Std. Dev. 

Site Index 79.9306 60 100 10.2757 

Dbh 11.6653 8.6 20.6 2.64192 

Saw Log Height 37.9861 12 7 6 15.1602 

-2 LOG LIKELIHOOD FOR MODEL CONTAINING INTERCEPTS ONLY = 248.53 

MODEL CHI-SQUARE = 66.06 WITH 3 D.F. (SCORE STAT.) P = 0.0 

CONVERGENCE IN 6 ITERATIONS WITH 0 STEP HALVINGS R = 0.503 

MAX ABSOLUTE DERIVATIVE = 0.1029D-06. -2 LOG L = 179.62 

MODEL CHI-SQUARE = 68.91 WITH 3 D.F. (-2 LOG L.R.) P = 0.0 

Variable Bet a Std. Error Chi-square P R 

A1 phal 4.94349250 1.87303953 6.97 0.0083 

A1 pha2 2.24502530 1.78911764 1.57 0.2095 

Site 0.05810954 0.02106371 7.61 0.0058 0.150 

Dbh -0.33812881 0.11144510 9.21 0.0024 -0.170 

Saw Log Height -0.05748074 0.02102516 7.47 0.0063 -0.148 

C = 0.844 Somer Dyx = 0.688 Gamma = 0.692 tau-a = 0.35 

Table 2.--Frequency Table of Actual Log 

Grade verus Predicted Log Grade 

Pred icted Log Grade 

Actual 

Log 

Grade 

3 

Total 8 32 104 144 

0 9 82 9 1 
Table 3.--The Predicition of Crown Class, using Proc Logist 

342 Observations 

129 Crown Class = 0 

95 Crown Class = 1 

72 Crown Class = 2 

46 Crown Class = 3 

0 Observations deleted due to missing values 

Variable Mean Mi n imum Max imum Std. Dev, 

Basal Area Bigger 56.6959 10 200 36.2771 

Dbh 8.37134 1.4 20.6 3.56795 

Site Index 78.1287 50 100 11.0984 

-2 LOG LIKELIHOOD FOR MODEL CONTAINING INTERCEPTS ONLY = 903.87 

MODEL CHI-SQUARE= 207.16 WITH 3 D.F. (SCORE STAT. ) P = 0.0 

CONVERGENCE IN 6 ITERATIONS WITH 0 STEP HALVINGS R = 0.485 

MAX ABSOLUTE DERIVATIVE = 0.44180-08. -2 LOG L = 685.41 

MODEL CHI-SQUARE = 218.45 WITH 3 D.F. (-2 LOG L.R.) P = 0.0 

Variable Beta Std . Error Chi -Square P R 

A1 phal 0.33336046 0.78198519 0.18 0.6699 

A1 pha2 -1.54389519 0.78421665 3.88 0.0490 

A1 pha3 -3.43248757 0.80670645 18.10 0.0000 

Basal Area Bigger 0.02308911 0.00391802 34.73 0.0000 0.190 

Dbh -0.37443864 0.04776247 61.46 0.0000 -0.256 

Site Index 0.02988253 0.01055918 8.01 0.0047 0.082 

C=0.827 SomerDyx=0.655 Gamma = 0.656 tau-a = 0.47 

Fable 4.--Frequency Table of Actual Crown Class verus 

Predicted Crown Class 

Predicted Crown Class 

FREQUENCY 1 

Class 

O 1 99 1 26 1 I 0 1 129 

Actual 

Crown 

0 

3 

1 

Total 149 85 7 8 30 342 

0 

2 

8 

3 

19 

Total 

19 46 
frequency table of actual crown class versus 

predicted crown class. With this model, 

predictions agreed with actual observations in 

56% of the cases and were within 1 class 93% of 

the time. However, it is noteworthy that 

predictions were correct 77 % of class 0 

(dominants), 37 % of class 1 (co-dominants), 51 % 

of class 2 (intermediates), and 41% of class 3 

(suppressed). 

EXAMPLE 3. TREE CLASSES 

Tree class is another common variable collected 

in CFI data. In these data, tree classes were 

represented by : 

0 - Desirable Tree 

1 - Acceptable Tree 

2 - Undesirable Tree 

3 - Cull Tree 

Very few observations existed in category 3. 

Therefore, to avoid problems of convergence to 

the maximum likelikood estimate, categories 2 and 

3 were combined. Variables selected to model 

tree class were total height, crown class, and. 

dbh. Table 5 shows the results from Proc Logist. 

Once again, the mode: was only a moderate fit. 

Table 6 displays a frequency table of actual tree 

class versus predicted tree class. With this 

model, predictions agreed with actual tree 

classes 65% of the time, and were within 1 class 

99% of the 

CONCLUSIONS 

This paper has presented the theory and 

methodology by which mu1 tiple classifications may 

be predicted. Examples of predictions for log 

grade, tree class, and crown class were given. 

The results from these predictions, though not 

always perfect were acceptable. A1 so, the 

examples were for categories which are highly 

subjective in their measurements. Therefore any 

prediction will be imperfect. Furthermore, when 

the alternative is to not divide predictions into 

classes, logistic regression is very desirable. 

LITERATURE CITED 

Affi, A.A. and V. Clark. Computer-Aided 

Multivariate Analysis. Belmont, Ca. 

Lifetime Learning Publications. 1984. 

458 pp. 

Anderson, J.A. Logistic discrimination. In: 

Krishnaiah, P.R. and L.N. Kana1 (eds.), 

Handbook of statistics, Vol 2. New York. 

New Holl and Pub1 i shing Company. 1982. 

169-191. 

Goodman, L.A. and W.H. Kruskal. Measueres of 

Association for Cross Classifications. New 

York: Springer-Verlag. 1979. 146 pp. 

Hamiliton, D.A. Jr. Event Probabilities 

estimated by Regerssion. USDA For. Serv. 

Res. Pap. INT-152. Intermt. For, and 

Range Exp. Sta., Ogden. 1974. 18 pp. 

Harrell. F.E. Jr. The LOGIST Procedure. 

In SUGI Supplemental User's Guide, 

Version 5 edition. SAS Institute 

Inc. Cary, N.C. 1986. 269-293. 

Monserud, R.A. Simulation of Forest Tree 

Mortality. For. Sci. 22(4):438-444. 1976. 

Vitaliano, P.P. The Use of Logistic Regression 

for Mode11 ing Risk Factors: With Application 

to Non-Melanoma0 Skin Cancer. Am. Jor. of 

Epidemiolgy 108(5):420-414. 1978. 

Walker, S.H. and D.B. Duncan. Estimation of the 

probability of an event as a function of 

several independent variables. Biometrika 54: 

176-179. 1967. 
Table 5.--Resul ts of the Prediction of Tree 

Class, using Proc Logist. 

344 Observations 

102 Tree Class = 0 

156 Tree Class = 1 

86 Tree Class = 2 

0 Observations deleted due to missing values 

Variable Mean Minimum Max imum Std. Dev. 

Crown Class 3.09012 1 5 1.0666 

Total Height 52.5698 15 102 17,514 

Dbh 8,3686 1.4 20.6 3.56067 

-2 LOG LIKELIHOOD FOR MODEL CONTAINING INTERCEPTS ONLY = 733.16 

MODEL CHI-SQUARE = 181.59 WITH 3 D,F. (SCORE STAT.) P = 0,O 

CONVERGENCE IN 6 ITERATIONS WITH 0 STEP HALVINGS R = 0.501 

MAX ABSOLUTE DERIVATIVE = 0.2973D-07. -2 LOG L = 543.40 

MODEL CHI-SQUARE = 189.76 WITH 3 D.F. (-2 LOG L.R.) P = 0.0 

Variable Beta Std. Error Chi-square P R 

A1 phal 0.84292520 0.67989908 1.54 0.2151 

A1 pha2 -2.22047247 0.70662535 9.87 0.0017 

Crown Class 1.01485148 0.14398809 49.68 0.0000 0.255 

Total Height -0.03106537 0.01271129 5.97 0,0145 -0.074 

Dbh -0.11394357 0.06938842 2.70 0.1006 -0.031 

C=0.826 Somer Dyx = 0.652 Gamma = 0.654 tau-a = 0.42 

Table 6.--Frequency Table of Actual Tree Class 

verus Predicted Tree Class 

Predicted Tree Class 

Actual 

Tree 

Class 

Total 

102 

Total 91 175 78 344 
Preserving and Maintaining 

Permanent Growth & Yield Research Plots 1 

J, David Lenhart 2 

Abstract.--In a comprehensive long-term plantation 

research project, a relatively large proportion of 

a carefully installed set of permanent plots have 

bean lost or destroyed within the initial five years 

due to acts of nature or man. As a result, the 

program to protect, preserve and maintain existing 

plots plus re-establish lost plots has intensified. 

When we installed a comprehensive set of 

permanent plots throughout East Texas on 

industrial forest lands during 1982, 1983 and 1984 

to provide data to drive the East Texas Pine 

Plantation Research Project for the next 20-30 

years, we accepted the fact that occasionally a 

plot will be lost due to reasons beyond our 

control. And when a plot is ruined or destroyed, 

we would re-establish the plot as soon as 

possible. In this manner, the tracking of 

plantation development is quickly re-started. 

PLOT UTILIZATION 

A total of 256 plots--178 in loblolly (Pinus 

taeda L.) and 78 in slash pine (Pinus elliottii 

Engelm.) plantations--were initially installed 

throughout East Texas by SFASU, School of Forestry 

personnel (Lenhart et al. 1985). Each 

rectangularly shaped plot is 1.2 acres in size. 

We are monitoring he growth and development of 

the planted pines plus sampling and measuring 

other environmental factors, which may be 

affecting the production of wood by the pine 

trees. Plot remeasurement is on a 3-year cycle, 

and the ETPPRP is expected to terminate in 2012. 

Numerous graduate students, faculty members and 

industry personnel are currently studying and 

analyzing the plantation values and, thus, are 

dependent on the ETPPRP plots as a primary data 

INITIAL PRESERVATION AND MAINTENANCE PLAN 

The participating landowners and the School of 

Forestry recognized the importance of maintaining 

and preserving a set of permanent plots. Our 

initial plan to try and insure that each plot 

survived until its final harvest, which may be 

10-30 years in the future, consisted of: 

1. Remeasuring plots on 3-4 year cycle. 

2. Informing company personnel of plot 

locations. 

3. Marking the research plots on all company 

maps. 

4. Encouraging companies to avoid potentially 

adverse activities around the plots. 

There are approximately two million acres of 

pine plantations on industrial forest land in 

East Texas. Our 256 plots represent a sample of 

307 acres or 0.015 percent of the total planted 

acreage. We felt that the completely random 

probability of an individual damaging activity 

occurring within any of the 256 plots, much 

less on a single plot, was extremely small. We 

were confident that a very large proportion of 

our sample should be spared from destructive 

forces, even during a long-range project such as 

the ETPPRP. 

PLOT DESTRUCTION 

source. 

After the initial five years of operating the 

ETPPRP, an interesting and unexpected set of 

reasons has caused a reidtively large loss of 27 

of the 256 permanent plots, Table 1, 

Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

Professor, School of Forestry, Stephen F. 

Austin State University, 

Nacogdoches, Texas 75962. 
Table 1. Summary of ETPPRP plots destroyed 

1982-86. 

Reason 

Land sale 

Southern Pine Beetle 

Incorrect plot location 

RabbitslAnts 

Vandalized 

Prescribed fire 

Oil/gas well construction 

Replanted 

Rifle range construction 

Deer stand construction 

Road construction 

Wildf ire 

Choked by tag wires 

Number 

6 

3 

3 

2 

2 

2 

2 

2 

1 

1 

1 

1 

To our surprise, ownership changes of the land 

where plots are located are the primary reason for 

loss of research plots. Owens-Illinois, Inc., one 

of the five original participating companies, sold some of their land to a developer. That developer 

is now the proud owner of six research plots. 

Of the 27 destroyed plots, only 5 were lost due 

to acts of nature-rabbits and SPB-and basically 

esuld not be controiled by man. The 22 remaining 

plots were destroyed by the actions of man. In 

some instances, perhaps, either ETPPRP personnel 

or company personnel could have prevented plot 

destruction. However, the rifle range and deer 

stand were constructed on hunting leases without 

permission and contrary to lease regulations. In 

the case of oil/gas well construction, company 

personnel, as usual, had no control over where the 

well pads were located. By the way, both holes were dry. 

REVISED PRESERVATION AND MAINTENANCE PLAN 

5-6 plots per year on the average, We have been 

able to re-establish 10 of the 27 plots, so at 

this point, our net loss is 17 plots. For the 

remaining years of the ETPPRP, we will intensffy 

our original plot survival procedures. In 

addition, we have decided to: 

1. Remeasure plots on a 3-year cycle. 

2. Keep field personnel informed of plot 

locations. 

3. Paint a bright line around all 960 feet of 

buffer zone perimeter. 

4. Post research area signs along the buffer 

zone perimeter. 

5. Flag the perimeter bf each of the two 

subplots within a plot. 

We hope that by making the research plots very 

visible, inadvertent intrusion and destruction 

will be minimized. 

We have also realized that in order to prevent 

our research plots from slowly dwindling away, 

we must be more active in plot re-establishment 

than we had originally thought. 

ACKNOWLEDGMENT 

Support from the four participating forest 

industries--Champion International Corporation, 

International Paper Company, Louisiana-Pacific 

Corporation and Temple-EasTex, 1nc.--is 

gratefully appreciated. 

LITERATURE CITED 

Lenhart, J. D., E. V. Hunt, Jr. and J. A. 

Blockard. Establishment of permanent growth 

and yield plots in loblolly and slash pine 

plantations in East Texas. In: E. Shoulders, 

editor Proceedings, Third Biennial South. 

Silvic. Res. Conf.; 1984 November 7-8; 

Atlanta, GA: U.S.D.A. For. Serv. Gen. Tech. 

Rep. SO-54; 1985: 436-437. 

In the initial five years of this approximately 

30-year long project, we have lost 27 of our 

original 256 plots (11 percent or 1 in 9) or about 
Incorporating Precipitation into a 

Basal Area Growth ~odell/ 

Paul A. Elurphy and Robert M. Farrar, ~r./ 

Abstract.--The Cbpman-Richards function was selected 

as the model for basal area development of uneven-aged 

loblolly-shortleaf pine stands. This function uses initial 

basal area and elapsed time as independent variables; it 

was modified to include various measures of growing season 

rainfall. July-September rainfall increased the predictive 

power of the basal area equation and was superior to other 

rainfall variables, The equations using the other rainfall 

variables were not better than the basic model. Though 

gains were not as great as anticipated, use of growing 

season rainfall as a variable in growth and yield models 

merits further study. 

Keywords: Eathematical models, growth and yield, rainfall. 

INTRODUCTION 

It has long been recognized that tree growth 

is greatly affected by the amount and timing of 

precipitation. Indeed, pioneering work by Coile 

(1936) on the effect of rainfall and temperature 

cites still earlier experimental work on the 

southern pines by Lodewick (1930). 

At the start of the growing season, the soil 

is usually at field capacity, having been 

recharged during the winter months of higher 

rainfall and lower evapotranspiration. As the 

growing season progresses and temperatures 

increase, evapotranspiration demands become 

larger and rainfall may decrease, which puts 

demands on the water supply in the soil. If 

potential evapotranspiration exceeds actual 

transpiration, a moisture deficit occurs. This 

situation is ameliorated late in the growing 

season when evapotranspiration demands lessen, 

Summer droughts exacerbate these soil-moisture 

deficits. 

It was the common occurrence of summer 

droughts in the West Gulf Coastal Plain that 

l/paper presented at Fourth Biennial Southern 

Silvicultural Research Conference, Atlanta, GA, 

November 4-6, 1986, 

/principal Nensurationists, Forestry Sciences 

Laboratory, Nonticello, AR, Southern Forest 

Experiment Station, U.3, Department of Agriculture, Forest Service, in cooperation with the 

Department of Forest Resources and Arkansas 

Agricultural Experiment Station, University of 

Arkansas at Monticello, 

spurred research on growing season soil-moisture 

deficiencies at the Crossett Experimental Forest 

in the 1950's and 1960's. Moyle and Zahner 

(1954) and Zahner (1955) found that undisturbed 

forests of different species compositions on 

similar soils had essentially the same summer 

soil-moisture depletion, which substantiated the 

supposition that potential evapotranspiration is 

independent of vegetative cover. Zahner (1958)~ 

in contrast to undisturbed stands, found that 

understory hardwood removal increased the soil 

moisture available to the loblolly and shortleaf 

pine (pinus taeda L., P, echinata ill.) overstory. ~asse-I 964a) found that when even-aged 

loblolly-shortleaf pine stands were periodically 

thinned, those thinned to higher densities 

experienced declines soil moisture and less 

diameter growth than stands thinned to a low 

density. Sometimes the stands thinned to the low 

density did not even experience a lessening in 

diameter growth because available soil moisture 

was not depleted, 

Bassett (1964b) quantitatively investigated 

the relationship between soil moisture availability and basal-area and cubic-foot volume 

growth of an uneven-aged loblolly-shortleaf pine 

stand by linear regression. His independent 

variables, growth days and growth-day index, are 

too complicated to use on an operational basis, 

but his work shows that soil moisture or related 

variables can be used in growth and yield projection equations. Zahner and Stage (1966) 

proposed a method for calculating daily moisture 

stress that can be used in diameter growth 

equations. In a more recent work, Shoulders and 

Tiarks (1980) developed prediction equations for 

the total height of 20-year-old plantation trees 

of the major southern pines using rainfall, 

slope, and available soil moisture as variables. 
Beck (1985) has also used a growing season precipitation variable to model the annual diameter 

growth of yellow-poplar (~iriodendron tuli fera 

L) Chang and Aguilar (1980) investigate: the 

effects of climate and soil on the radial growth 

of loblolly pine, 

These studies and many others reviewed by 

Zahner (1968) have conclusively demonstrated that 

precipitation and soil moisture can each affect 

tree growth The studies cited here have either 

evaluated how soil moisture and rainfall have 

affected seasonal growth or have used elaborate 

indices based on daily measures of soil moisture 

and other variables to evaluate periodic growth 

of several years, There has not been an analysis 

that has attempted to relate periodic diameter or 

basal area growth of several years to cumulative 

rainfall of the same period. 

Most growth and yield studies have used 

variables such as stand density, site index, 

stand age, or length of the growth period to 

forecast stand growth and development. Long-term 

growth studies are now being used to assess the 

impact of atmospheric deposition, and it is 

important to eliminate climatic effects before 

evaluating pollution impacts, Otherwise, atmospheric deposition or other factor may be 

improperly identified as the causal agent when it 

actually may be climate. 

Rainfall records are easily available, and 

precipitation data have been collected intensively for many years, Since soil moisture is a 

prime factor of tree and stand growth, and rainfall is highly correlated with soil moisture, 

rainfall can act as a surrogate variable, Thus, 

growing season rainfall is a primary climatic 

variable to include in growth and yield 

equations. 

We decided to examine the feasibility of 

incorporating precipitation into a basal area 

projection model for uneven-aged loblollyshortleaf pine stands in southern Arkansas. We 

wanted to determine if periodic rainfall could be 

related to periodic basal area growth, The term 

"periodic" is used to imply an interval of 

several years. 

DATA 

The data we used are from the cutting cycle 

study (~eynolds 1959, 1969), the methods-ofcutting study ( Baker and Murphy 1982, Grano 

1954), and unpublished research conducted at the 

Crossett Experimental Forest and adjacent areas 

in south Arkansas in uneven-aged loblollyshortleaf pine stands. An uneven-aged loblollyshortleaf pine growth and yield model has also 

been developed using these data (~arrar and 

others 1984; Murphy and Farrar 1982, 1983). 

The predominant soil in these stands is Bude 

silt loam, which is a member of the fine-silty, 

mixed thermic family of Glossaquic Fragiudalfs, 

The site index for loblolly pine is 80 to 90 feet 

at base age 50 (US. Department of Agriculture, 

Forest Service 1976). 

Stand growth information was obtained from 

periodic 100-percent cruises of plots and compartments that ranged from 2.5 to more than 40 

acres in size, Records were kept of stand 

inventories, harvest cuts, salvage cuts, and 

thinnings by I-inch classes for loblolly and 

shortleaf pine trees 3-6 inches in d.b.h, and 

larger. Remeasurement intervals varied from 3 to 

9 years. Collection of most of these data 

started in 1937 and continued into the late 

1960ts. 

All species were tallied in the methods-ofcutting study, and all were initially inventoried 

in the cutting cycle study by 10-acre subcompartments. In 1948, all hardwoods on the cutting 

cycle study were controlled by injecting or 

girdling, and thereafter tallies were kept only 

for pine by 40-acre compartments. 

Basal areas per acre were calculated for 

shortleaf and loblolly pine trees 3.6 inches and 

larger in d.b.h. If a harvest occurred within 

hlf a growing season of the initial inventory, 

its basal area was deducted fr~m the initial 

value; otherwise harvest basal areas were added 

to the ending basal area, The difference between 

initial and final values provides an observation 

on net change resulting from survivor growth, 

ingrowth, mortality, and growth on harvested 

trees. Any observations showing a negative 

change (indicating excessive mortality) were 

deleted from the analysis, Most compartments 

were measured several times and yielded several 

growth observations. The final number of observations was 421. 

Weather records were kept on the Crossett 

Experimental Forest from 1934 through 1973. 

Average annual precipitation for the 40 years of 

record was 53.34 inches. Figure 1 shows the 

average monthly rainfall for the period, It is 

highest in the winter months and declines during 

the growing season through October, except for a 

mild increase in July. Summer droughts are 

common; the average growing season rainfall 

i arch through ~ctober) is 33.49 inches, but it 

has ranged from 19.24 to 56.36 inches, 

Monthly summaries of these data were used to 

compute different measures of growing season 

rainfall during each growth period, For 

example, if the growth period occurred in the 

years 1955 to 1958, the different growing season 

rainfalls for this period would be accumulated 

for this growth observation, The different rainfall variables were the cumulative amounts for 

the following groups of months: March through 

October, March through May, June through August, 

and July through September. June, July, and 

August were included as individual months to 
6 

\ 

2 

x 

t, 

3 \c * 

z .2 

% 

t, 

2 

Q, 

0 

JAN FE8 MAR APR MAY JUN JUL AUG SEP OCT NOV DEC 

Figure 1.--Average monthly precipitation, 1934 to 1973,-Crossett Experimental Forest, south Arkansas. 

assess the relative importance of each of the 

summer months to basal area growth. 

ANALYSIS 

The basal area projection equation originally 

used by Noser and Hall (1969) for uneven-aged 

stands and later by Murphy and Farrar (1982) was 

selected for this investigation. It is the 

Chapman-Richards function and may be written in 

the following form for our analysis: 

where 

B1 = basal area (ft2 per acre) at start of 

period, 

B2 = basal area (ft2 per acre) at end of period, 

t = period length in years, 

pi = parameters to be estimated, and 

exp = exponent of e. 

A desirable feature of my growth and yield 

model is predictive invariance, that is--projecting from times tl to t2 and then to t3 

(tl<t2<tj) gives the same answer as projecting 

from tl to t3 in one step, Deriving a projection 

model, such as equation (I), by integrating a 

growth model guarantees that the resulting projection equation will have this property. 

An attempt was initially made to incorporate 

rainfall as a variable in addition to elapsed 

time and simultaneously preserve the predictive 

invariance of equation (1). However, this 

attempt was unsuccessful. The measure of rainfall (r ) was used in lieu of elapsed time as an alternative approach, 

where the other variables are as previously 

defined. Equation (2) has the property of predictive invariance. Thus, nine models were 

tested: equation (I), using elapsed time, and 

equation (2), using eight different growingseason rainfall variables (ri). The nine models 

were fitted by nonlinear least squares (~ixon 

1981 ) . 

A set of 306 observations was randomly 

selected from the original data to conform to 

software limitations on the number of observations and variables; the random selection 

procedure was modified to obtain a more rectangular distribution of data than wss in the 

original data set. The statistics for the final 

306 observations are: 
Variable - Nean Standard deviation 

Rainfall 

Nar-0ct 

Jun-Oct 

Mar-May 

Jun-Aug 

Sul-Sep 

Jun 

Jul 

Aug 

The rainfall statistics are for cumulative rain 

during the growth period; they are not annual. 

Table 1 gives fit statistics for the nine 

equations. The equation using JulyLSeptember 

rainfall performed the best overall according to 

the fit criteria, although the improvement over 

elapsed time alone was real dramatic. All other 

equations gave results worse than the basic 

model. The results for June, July, and August 

indicate that July rainfall explains more 

variation than either June or August; a rationale 

might be that variation in rainfall is greater in 

July than either June or August and, consequently, contributes more to basal area growth, 

CONCLUSION 

These preliminary results show that including 

growing season rainfall, notably July-September, 

does increase the predictive power of the basal 

area pro jection equation used here. The gains 

are somewhat modest, because initial basal area 

and elapsed time do a good job of describing 

basal area development in the original model. 

Further investigation is warranted to determine which combination of months are best, Since 

the months should be contiguous, the number of 

equations to test are large but not overwhelming. 

There are 8 growing season months; therefore, 

there are 36 possible combinations of contiguous 

months varying from 1 to 8 months in length. 

Another approach worth studying is the inclusion of soil-water budgets. Fortunately, this 

approach will soo be facilitated by a software 

package by Zahnez-37 that calculates potential 

evapotranspiration and soil-moisture 

deficiencies along with an index of how much 

potential tree growth is affected on a daily 

basis. 

LITERATURE CITED 

Table 1.-St statistics for diffemt hsd area projecticn 

mdels 

A~1~ deviati&I 

Fit 

variable M.S.E~ A B&! standard cieviatim 

Baker, James B.; ivfurphy Paul A, Growth and yield 

following four reproduction cutting methods in 

loblolly-shortleaf pine stands--a case study. 

Southern Journal of Applied Forestry. 6: 66-74; 

1982. 

Bassett, John R. Diameter growth of loblolly pine 

trees as affected by soil-moisture availability. Res. Pap. SO-9. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1964a. 7 p. 

Bassett, John R. Tree growth as affected by soil 

moisture availability. Soil Science Society of 

America Proceedings, 28: 436-438; 1964b. 

Beck, Donald E. Is precipitation a useful 

variable in modeling diarne ter growth of yellowpoplar? In: Shoulders, Eugene, ed, Proceedings 

of the 3rd biennial southern silvicultural 

research conference; 1984 November 7-8; 

Atlanta, GA. Gen, Tech. Rep. SO-54. New 

Orleans, LA: U,S, &partmend of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1985. p. 555-551. 

2/Personal communication, June 20, 1986, Robert 

Zahner, College of Forest and Recreation 

Resources, Clemson University, Clemson, SC 29631. 
Chang, PI,; Aquilar, G.J. Effects of climate and 

soil on the radial growth of loblolly pine in a 

humid environment of southern USA. Forest 

Ecology and Hanagement. 3: 141-150; 1980, 

Coile, T.S. The effect of rainfall and temperature on the annual radial growth of pine in the 

southern United States. Ecological Monographs, 

6: 534-562; 1936. 

Dixon, W.J., ed. BPIDP statistical software, 1981. 

Berkeley, CA: University of California Press; 

1981 (p. 305-3141. 725 p. 

Farrar, Robert M, Jr.; Murphy, Paul A,; Willett, 

R. Larry. Tables for estimating growth and 

yield of uneven-aged stands of loblollyshortleaf pine on average sites in the West 

Gulf area. Bull. 874. Fayetteville, AR: University of Arkansas, Division of Agriculture, 

Arkansas Agricultural Experiment Station; 1984. 

21 p. 

Grano, Charles X. Re-establishment of shortleafloblolly pine under four cutting methods. 

Journal of Forestry. 52: 132-133; 1954, 

Lodewick, J.E. Effect of certain climatic factors 

on the diameter growth of longleaf pine in 

western Florida. Journal of Agricultural 

Research, 41 : 349-363; ?930. 

Moyle, Ralph C,; Zahner, Robert. Soil moisture as 

affected by stand conditions. Occas. Paper 137, 

New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest 

Experiment Station; 1954. 14 p. 

Moser; John W., Jr.; Hall, Otis F. Deriving 

growth and yield functions for uneven-aged 

stands. Forest Science 15.: 183-188; 1969, 

Murphy, Paul A.; Farrar, Robert M., Jr. Interim 

models for basal area and volume projection for 

uneven-aged loblolly-shortleaf pine stands. 

Southern Journal of Applied Forestry. 6: 115- 

119; 1982. 

Murphy, Paul A*; Farrar, Robert N., Jr. Sawtimber 

volume predictions for uneven-aged loblollyshortleaf pine stands. Southern Journal of 

Applied Forestry. 7: 45-50; 1983. 

Reynolds, R.R. Eighteen years of selection timber 

management on the Crossett Experimental Forest. 

Tech. Bull. 1206. Washington, DC: U.S. 

Department of Agriculture, Forest Service; 

1959. 68 p. 

Reynolds, R.R. Twenty-nine years of selection 

timber management on the Crossett Experimental 

Forest. Res. Paper SO-40. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1969. 19 p. 

avsilable soil moisture. Forest Science. 26: 

437-447; 1980. 

Thornthwaite, C.W. An approach toward a rational 

classification of climate. Geographical Review, 

38: 55-94; 1948. 

U.S. Wpartment of Agriculture, Forest Service. 

Volume, yield, and stand tables for secondgrowth southern pines. Misc. Publ. 50. 

Washington, DC: U.S. Department of Agriculture, 

Forest Service; 1976 [revision of 1929 

edition]. 202 p, 

Zahner, Robert. Soil water depletion by pine and 

hardwood stands during a dry season. Forest 

Science, 1: 258-264; 1955. 

Zahner, Robert. Evaluating summer water 

deficiencies, Occas. Paper 150. New Orleans, 

LA: U,S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1956. 18 p, 

Zahner, Robert. Hardwood understory depletes soil 

water in pine stands. Forest Science. 3: 178- 

184; 1958. 

Zahner, Robert, Water deficits and growth of 

trees. In: Kozlowski, T.T., ed, Water deficits 

acd plant growth, volume 11, New York: Academic 

Press; 1968, p. 191-254, 

Zahner, Robert; Stage, Albert R. A procedure for 

calculating daily moisture stress and its 

utility in regressions of tree growth on 

weather. Ecology. 47: 64-74; 1966. 

Shoulders, Eugene; Tiarks, Allan E. Predicting 

height and relative performance of major 

southern pines from rainfall, slope, and 

Pest Management 

Moderator: 

Thomas E. Miller 

Southeastern Forest Experiment Station 

Impact of Pine Tip Moth Attack on Loblolly Pine Seedlings 1 

Roy L. Hedden and D. A. Naugen 

2 

ABSTRACT.--Impact of Nantucket pine tip moth attack on height, diameter and biomass of 3 year-old loblolly pine trees was measured in a 

planted stand in northwestern South Carolina. Twelve, 0.25 acre plots 

were established in 1984, and in 1985 two insecticide treatment 

regimes were applied to 8 of the plots. In four plots, the insecticide sprays were applied three times to coincide with the three annual 

tip moth generations, while in the other four insecticide plots, 

sprays were applied to only the spring generation. Four of the plots 

were untreated check plots. In each plot, 25 measurement trees were 

tagged during the 1984 growing season. The height and diameter of 

each tree at the end of the 1984 and 1985 growing seasons was 

measured. Furthermore, five trees were selected at the end of the 

1985 growing season from each of the check and three-spray plots for 

biomass sampling. Statistical analysis of the data revealed that 

thereswere significant (P < .05) differences in height at the end of 

the 1985 growing season between the insecticide and the check 

treatments. Significant differences in diameter occurred only between 

the three-spray and the check treatment. There were also significant 

differences in estimated biomass between the check and three-spray 

treatments. Howev?r, a single combined regression equation based on 

ln(y) = a + b ln(D H) adequately described the relationship between 

biomass (foliage, branch, stem and total) and diameter and height for 

both treatments. This analysis suggests that the impact of the 

Nantucket pine tip moth on loblolly pine results from attacks 

preventing full development of potential photosynthetic area. The 

importance of these differences to long-term impact of Nantucket pine 

tip moth is discussed. 

INTRODUCTION 

The Nantucket pine tip moth, Rhyacionia 

frustrana (Comstock), is a well known pest of 

loblolly and other species of southern pines. 

Numerous studies have been conducted to estimate 

its impact on young pines, but the circumstances 

where control are warranted afe still not well 

defined. In virtually all cases, the studies show 

reduced diameter and height growth in younger 

trees, however some long term studies indicate 

that reduction in height growth is transitory 

(Warren and Young 1972; Shepard 1973; Stephen et 

al. 1982). Even though reductions in height may 

be temporary, tip moth (UPTM) impact on diameter 

is real and persistent, resulting in a significant 

reduction in volume (Williston and Barras 1977; 

Cade and Hedden, In press), Tip moth attack may 

result in other forms of impact in addition to 

growth loss, For instance, Hedden and Clason 

(1980) suggest that NPTM attack also can cause 

reductions in wood and lumber quality. 

'paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, 

November 4-6, 1986. 

2~rofessor and Research Associate, Department of 

Forestry, Clemson University, Clemson, South 

Carolina. 

The NPTM also interacts with other pests to 

cause greater damage than when either pest is 

found alone. Herbaceous weed control results 

in higher levels of tip moth attack due to an 

increased number of and more nutritious shoots 

available for attack (Hedden and Nebeker 1984; 

Nelson and Cade 1984). Increased numbers of 

attacks can provide a continuous supply of 

infection courts for the pitch canker fungus 

(S. C. Cade, personal communication). Furthermore, NPTM attack has been related to a significant increase in fusiform rust infection (Powers 

1985). These potential interactions, combined 

with the direct impact of NPTM attack on tree 

growth and quality, suggest that as the intensity 

of forest management increases, the importance of 

pine tip moths as pests of loblolly pine will also 

increase (Hedden and Nebeker 1984). 

In order to better understand the interaction 

of the NPTM with loblolly pine, we initiated a 

study in 1984 to investigate the impact of tip 

moth attack on tree growth. Numerous other 

studies have been conducted to investigate the 

impact of pine tip moth attack on diameter, 

height, and volume growth, but none of these 

efforts, with the possible exception of Hedden et 

al. (1981), has attempted to provide a detailed 

description of how NPTM effects tree growth, In 

the research reported herein, we show how the NPTM 

prevents the development of potential 

photosynthetic area, and how this reduction in 

leaf area affects tree growth. 
RESULTS ASD DISCUSSION 

Study Site 

The plantation is on a cut-over pine site on 

the Clemson University Experimental Forest in 

Pickens County, South Carolina. The previous 

stand was harvested in July 1981. The site was 

prepared by hand-clearing, piling in windrows and 

rootraking in October 1983. Improved loblolly 

pines were machine planted at a nominal 8 by 10 

foot spacing during February 1984. The site 

consists of gently rolling hills (slopes of 4% or 

less) typical of the upper Piedmont of South 

Carolina. The major soil series is a Hiwassee 

sandy loam with a small amount of Madison sandy 

loam. The average site index, for shortleaf pine, 

of the previous stand was about 80 feet (base age 

50 years). 

Experimental Design 

Four blocks, each 314 acre, were established 

in the fall of 1984. Blocking was done on the 

basis of slope and soil type, with 3 blocks of 

Hiwassee sandy loam and 1 block of Madison sandy 

loam. The blocks consisted of three 114 plots, 

each of which was randomly assigned one of 3 

treatments in 1985. Each plot was separated from 

every other by at least 1 or more buffer rows. 

Treatment 1 ("one-spray") consisted of one spray 

of fenvalerate (.I6 ozlgal a, i, [,024% a; 1.1) 

timed to coincide with the presence of the 

1st-instar NPTM larvae of the overwintering pine 

tip moth generation in 1985. Treatment 2 ("three; 

spray") consited of 3 fenvalerate sprays timed to 

coincide with the presence of Ist-instar larvae in 

each of the 3 annual NPTM generations in 1985. 

Treatment 3 ("check") consisted of unsprayed check 

plots. Permanent 25-tree measurement plots were 

established by tagging 5 adjacent trees in the 

inner 5 rows in each of the larger treatment 

plots. Plot measurements of height, basal 

diameter and the proportion of growing tips 

infested by the NPTM were made during the winters 

of 1984 and 1985. 

Biomass Sampling 

During the winter of 1985, 20 trees each from 

three-spray and check treatments, for a total of 

46 trees, were sampled for biomass. Five trees in 

each treatment were taken from each block. The 

sample trees were selected to represent the size 

classes present in the measurement plots. Each 

tree was subdivided into its component parts: 

stem, branches, and foliage (old and current). 

Current foliage was the needles from the last 

growth flush while old foliage was all other 

needles. The total dry weight of each component 

was determined to the nearest gram, The dry 

weight of ea~h comronent was modeled as ln(weight) 

= a + b ln(D"H) w'lere D = basal diameter (mm) and 

W = total he:ght (em). In addition to biomass, 

leaf area usieg the volume displacement method was 

derermined for old and current foliage following 

the procedure -f Johnson et al. (1985). 

At the end of the 1984 growing season there 

were no significant differences in year-end 

percentage of tip moth infested shoots (18.61 t 

sd = 22.35%) and at the beginning of the 1985 

growing season there were no significant 

differences in height (37 2 12 cm) or basal 

(ground line) diameter (8 2 2 mm) by block or 

treatment. However, by the end of the 1985 

growing season there were significant differences 

between treatments for some of the variables 

(Table I). Significant differences in height and 

infestation level were found between the 

three-spray and the other 2 treatments, but no 

noticeable differences were found for any of the 

variables between the one-spray and check 

treatments. 

Table 1.--Treatment means for height, basal 

diameter and year-end infestation in 1985. 

~reatment' Height Basal Infestation 

diameter level 

( cm) (mm) (2) 

Check 101a2 20a 44.3a 

Three-spray lllb 22a 1.3b 

I No. of treesltreatment = 100 

Means with different letter are significantly different at p < .05. 

The biomass subsample consisted of 20 trees 

from the three-spray and 20 trees from the check 

treatment. The mean height, basal diameter and % 

infested shoots for the check treatment were 

99.7 2 23.3 cm, 19.45 "6. mm, and 34.2 t 16.6 %. 

In the rhree-spray treatment the mean height was 

113.5 t 25.3 cm, mean basal diameter was 21.1 t 

4.6 mm, while the tip moth attack rate was 4.5t5.7 

% of the buds infested. These values are very 

similar to the mean values for the trees in the 

measurement plots (Table I). The leaf area and 

biomass values for these treatements are given in 

Table 2. 

The distribution of biomass in the trees is 

similar even though the weight of the individual 

components is always less in the check treatment. 

About 55% of the biomass is foliage with the stem 

and branches making up 32% and 13%, respectively. 

Also, relative leaf area (leaf arealfoliage 

weight) is very similar in both the check and 

three-spray trees. Indeed, an analysis of 

covariance showed that a single equation for each 

biomass component was adequate to describe the 

functional relationship between the variables 

(weight and basal diameter and height) for each 

treatment (Table 3). 
Table 2.--Dry weight and leaf area for the check LITERATURE CITED 

and three-spray treatments. 

Variable Check Three-spray 

Total tree (g) 137.8 191.5 * 1 

Stem (g) 45.0 60.0 

Branches (g) 17.3 23.1 

Foliage (g) 75.5 108.4 * 

~eaf area (cm2) 9,383.4 13,213.0 * 

Relative eaf 1 area (cm fg) 124.3 121.9 

means significantly different at p < .05 

Table 3.--Values for biomass regression equations 

for dry weight (gm) for tree components for the 

check and three-spray tre tme ts. Equation 9 P form: ln(W) = a + b ln(D H). 

Tree Intercept Slope R2 Sy.x 

component (a) (b) 

Total tree -3.37034 ,78221 .88 ,22643 

Stem -5,0807 1 .83445 .92 .I9674 

Branches -6,69000 .88787 .76 .38772 

Foliage -3.44 146 .73546 .84 .24972 

'W = weight in gm, D = basal diameter (mm) and 

H = total tree height (cm). 

Most of the difference in biomass between 

treatments is due to the difference in foliage 

weight (table 2). Tip moth attack represented a 

reduction in leaf area and foliage biomass of 

about 30%. This impact iis much greater than the 

the 10% reduction in height and diameter or the 2 18% difference in volume (D H) for 1985. This 

indicates tha-t the impact of NPTM attack is not 

totally expressed in the current year's volume. 

Impact in 1986 will partially be due the reduction 

in leaf area in 1985 plus the reduction which 

occurs in 1986. This pattern of impact will 

continue until after the trees are large enough to 

escape significant NPTM attack (Cade and Hedden, 

in press). Therefore, the net effect of attack i$ 

to delay the development of leaf area. This delay 

in combination with the early reduction in height 

increment lengthens the juvenile period of growth 

for the tree. This may be very important in 

prolonging the amount of time the tree may be 

exposed to pests of young trees in addition to the 

NPTM, especially fusiform rust where years of 

heavy inoculum production only occur periodically. 

Cade, Stephen C., and Roy L. Hedden. Growth 

impact of pine tip moth on loblolly pine 

plantations in the Ouachita mountains of 

Arkansas. So. J. Appl. For.; In press. 

Hedden, Roy L,, and Terry Clason. Nantucket pine 

tip moth impact on loblolly pine wood and 

product quality. In: For. Res. Rept. 1979, 

North Louisiana Hill Farm Expt. Stn., Homer, 

LA, pp. 57-72. LSU, Agric. Expt. Sta.; 1980. 

Hedden, Roy L., and T. Evan Nebeker. Integrated 

pest management in pine stands (0-5 

yrs.)--Insects. In: Proceed. Integrated 

Forest Pest Manag. Symp., Athens, GA, S. J. 

Branham and G, D. Hertel, eds. Univ. Ga., 

Center for Continuing Ed.; 1985:39-53. 

Hedden, R. L., J. A. Richmond, H. A. Thomas and J. 

H. Lashomb. Impact of pine tip moth on young 

loblolly pine biomass. In: Proceed. First 

Biennial South. Silv. Res. Conf., J. P. 

Barnett, ed. USDA For. Serv. Gen. Tech. 

Rept. SO-34. So. For. Expt. Stn., New 

Orleans, LA.; 1981:238-241. 

Nelson, Larry R. and Stephen C. Cade. Integrated 

pest management in pine stands (0-5 

years)--Vegetation. In: Proceed. Integrated 

Forest Pest Manag. Symp., Athens, GA, S. 3. 

Branham and G. D. Hertel, eds. Univ. Ga., 

Center for Continuing Educ.; 1985:72-87. 

Powers, H. R., Jr. Incidence of fusiform rust 

infection on loblolly pine related to tip 

moth damage. In: Proceed. of the Joint Conf. 

of IUFRO Working Parties on Forest Gall 

Midges and Rusts of Pine., Seoul, Korea, 

Je-Ho KO and Yong-Joon La, eds. Int. Union 

of For. Res, Org., Seoul, Korea.; 

1985:129-134. 

Shepard, R. $. The effect of tip moth control on 

height growth of loblolly pine. In: For. 

Res, Rept. 1973, North Louisiana Hill Farm 

Expt. Stn., Homer, LA, LSU, Agric. Expt. 

Sta.; 1973:55-58. 

Stephen, F. M., G. W, Wallis, R. J. Colvin, J. F. 

Young et al. Pine tree growth and yield: 

Influence of plant spacing, vegetation, and 

pine tip moth control. Arkansas Farm Res. 

31(2):10; 1982. 

Warren, L. O., and J, Young. Long-term effects of 

pine tip moth control. Arkansas Farm Res. 

21(2):4; 1982. 

Williston, H. L., and S. J. Barras. Impact of sip 

moth injury on growth and yield of 

16-year-old loblolly and shortleaf pine. 

USDA For. Serv. Res. Note SO-221. So. For. 

Expt. Stn., New Orleans, LA., 1977. 5p. 
A CROW RATING METBOD FOR ASSESSING TREE 

VIGOR OF LOBLOLLY AND SHORTLEAF PIP~ES~ 

R. L. Anderson and R. P, belager 

2 

Abstract.--Crown rating methods are commonly used 

in Europe to assess tree and stand vigor. Similar methods have not been developed for southern tree species. 

Because of recent concerns related to growth loss and 

forest decline in the South, a European method based on (I) percentage of foliage loss and (2) color of foliage 

was tried, modified, and tested on loblolly and shortleaf pines in the Piedmont of Georgia and South 

Carolina. This paper presents relationships between 

these crown vigor ratings and incremental radial growth. 

Results indicate crown density can be used to easily and 

quickly assess the relative tree and stand vigor of loblolly and shortleaf pines. Findings have silvicultural, 

forest management, and pest management implications. 

INTRODUCTION 

Foresters collect a variety of information 

in the normal management of a forest stand. 

Species, age, soil, site index, radial increment, and basal area data are routinely collected to better understand the characteristics 

of the stand and potential productivity of the 

site. Soil and site conditions influence 

management decisions such as species selection, 

site preparation methods, potential pest strategies, and determining rotation lengths. Variables such as age, radial increment, and basal 

area help determine thinning and harvesting 

schedules. In the process of collecting these 

data, crown class and live crown ratio are often 

observed but, in most cases, little use is made 

of this information. 

Many silvicultural practices such as thinning and timber stand improvement are directed 

toward improving crown development and subsequent tree vigor. Foresters began looking at 

the crowns on western pine species in the early 

1930's (Dunning 1928, Keen 1936). Salman in the 

1930's and 1940's developed a crown characteristics system on ponderosa pine (Pinus ponderosa 

Dougl. ex. Laws.) to predict susceptibility to 

bark beetle attacks (Smith and others 1981). 

In 1936, Keen developed an age and crown vigor 

classification system for ponderosa pine. In 

the 1950is, Hall developed a detailed crown 

classification system, also for ponderosa pine, 

that used needle conditions, twig and branch 

conditions, and top crown conditions (Hall 1951, 

1958). In 1962 (Smith and others 1981), a risk 

rating-system using crown conditions was further 

tested and has been expanded to other species, 

such as true fir (Abies spp.). 

The relationship between crown conditions 

and radial growth of individual trees has been 

examined for loblolly pine (P. taeda L.). 

Guttenberg (1953) found that fast-growing trees 

have longer and wider crowns than slow-growing 

trees. Deetlefs (1954) showed that doubling the 

crown-length ratio about doubled the basal area 

growth of individual trees as a result of a 

fourfold increase in relative crown surface, 

Grano (1957) reported that seed trees with dense 

crowns grew faster in diameter than trees with 

average or sparse crowns. Crown lengths and 

live crown ratio are strongly influenced by 

stand density. It is not known how stand 

conditions affect crown density. 

'paper presented at the Fourth Biennial 

Silvicultural Research Conference, Atlanta, GA, 

November 4-6, 1986. 

'supervisory Plant Pathologist, Region 8, 

Forest Pest Management, Asheville, NC, and 

Principal Silviculturist, Southeastern Forest 

Experiment Station, Athens, GA, USDA Forest 

Service. 

Crown classification systems have largely 

been ignored for shortleaf pine (P, echinata 

Mill.). An exception to this would be the 

research reported for littleleaf disease. Symptoms associated with this disease are expressed 

by a decline in general vigor and appearance of 

the crown. Guidelines are available for recognizing symptoms, evaluating the extent of the 

problem, and making management decisions 

(Anderson and Mistretta 1982; Campbell and 

Copeland 1954 ; Belanger , Hedden, and Tainter 

1985) * 
Crown vigor classifications have received 

considerable attention in Europe. A general 

decline in forest growth was reported in Germany 

around 1979 and had increased from 8 percent of 

the population of trees involved in 1979 to 

about 50 percent in 1984 (Schutt and Cowling 

1985). Many symptoms were observed for the 

affected trees: foliage loss, yellowing, 

decreased growth, loss of feeder roots, 

decreased diameter increment, death of older 

needles and leaves, and increased susceptibility 

to root and foliage pathogens. To assess this 

problem, nationwide surveys in Germany were 

begun in 1982 and are redone during a 5- to 6- 

week period each year. Sample plots are established throughout most of the country on a 2.5 x 

2.5 mile grid. A number of site parameters are 

collected, but two of the key parameters are 

percentage of foliage loss and foliage yellowing 

(Schroter and Aldinger 1985). These are combined to produce a damage rating for each tree 

and examined for each plot. The cause of the 

foliage loss or yellowing is not determined. 

However, it is generally felt that the condition 

of the crown reflects the vigor and health of 

the tree. 

Major reductions in the growth of yellow 

pines have recently been reported in the southeastern United States (Sheffield and others 

1985). Possible causes have been listed as 

atmospheric deposition, increased stand density, 

increasing stand age, increasing competition 

from hardwoods, drought, reduction in the water 

table, loss of old-field conditions, and 

increased impacts of insects and diseases. 

Since crown classification methods are used to 

successfully evaluate tree vigor and subsequent 

growth in Europe, a similar system was needed to 

visually evaluate the relative tree and stand 

vigor of southern pines. 

This study was designed to examine the relationship between crown conditions and radial 

increment for loblolly and shortleaf pine at 

various ages. If a correlation was found, then 

findings could have meaningful and beneficial 

implications for any forest management decision 

that uses vigor as a'variable. Examples would 

be pest hazard rating, thinning, determining 

rotation age, and establishing stand treatment 

priorities. 

Ten shortleaf pine stands from South 

Carolina and 11 loblolly pine stands from 

Georgia were selected for study. Each stand, at 

least 5 acres in size, had to be naturally 

generated, with the majority of the trees in the 

same age class. Stands had to be at least 20 

years of age and not over 80. Every attempt was 

made to obtain a uniform distribution of stands 

from 20 to 80. All stands had to bee free of 

recent disturbances such as fire, bark beetles, 

and thinning. 

In each stand, five smple points were 

selected at random to determine average st 

site, md individual tree characteristics. Yd * 

Stand characteristics included pine basal area, 

hardwood basal area, and percentage of the pine 

component by species. Tree characteristics 

included dimeter at breast height, total 

height, age, and radial increment for the last 5 

years. Site index for loblolly and shortleaf 

pines was calculated from age and height of 

dominmt md codominant trees (Sehumacher and 

Coile 1960). The Campbell and Copeland (1954) 

field-sating system for evaluating littleleaf 

disease hazard was recorded for each stand. 

This required an evaluation of erosion, subsoil 

consistency, zone to depth of reduced permeability, and subsoil mottling. 

Crown vigor was assessed in July 1986. 

Annual needle growth and crown development was 

at its maximum at this time. In each stand 20 

trees were selected for crown evaluation. The 

trees could not be on the edge of the stand or 

have major damage such as fusiform rust or storm 

breakage. The European crown vigor method used 

four classes of percentage of needle loss (0-25, 

26-50, 51-75, and 76-100) and three classes of 

yellowing (0-25, 26-60, and 61-100). We elected 

to use nine classes of needle loss ranging in 

percentages of 10 from 10 to 90. This gradation 

would provide more detailed information for 

statistical analysis, and could be regrouped 

into broader categories if needed. 

Each tree was examined so the crown could be 

seen from the side by two people. Estimates of 

percentage needle loss were made by each person 

separately, compared, and adjusted until agreement was reached or averaged if not off by more 

than one class. To make the estimate, the portion of the crown containing some live needles 

was considered for observation (fig. 1). 

The classification of crowns into the 10 

percent crown class was relatively easy. In 

most cases, the two viewers agreed. If they did 

disagree, it was normally by a 10 percent difference. In those cases, the tree was assigned a 

value between the two observations--e.g., estimates of 30 and 40 percent foliage loss were 

rated as 35 percent. Every attempt was made to 

obtain a full range of density classes from 10 

to 90 percent. Yellowing was assessed based on 

the percentage of yellow needles on the total 

crown. 

The crown class and diameter at breast 

height were recorded f'or all sample trees. Each 

tree was bored at 4.5 feet and the core examined 

in the field, The radial increment in millimeters was recorded for the three most recent 

5-year growing periods (0-5, 6-10, and 11-15 

years), 

Loblolly and shortleaf stands were analyzed 

as separate timber types. Age categories were 

classified as young (<40 years of age) and 

mature (240 years). 

3~he authors thank Colleen Scarrow. 

Technician, Forest Pest Management, Asheville, 

NC, for assistance in data collection. 
Figure 1.--Percentage of foliage loss was used to assess crown density. 

Examples are: A = 20 percent foliage loss, B = 60 percent loss, and 

C = 90 percent loss. 

STAND AND SITE CHARACTERISTICS 

The loblolly pine stands selected for the 

s-dy were on the Chattahoochee-Oconee National 

Forest in Green, Jasper, and Morgan Counties, 

Georgia. The 11 loblolly stands averaged 45 

years of age and ranged from 21 to 67 years 

(table 1). Average site index (loblolly at base 

age 50 years) was 81. This is higher than the 

mean of 76 reported for natural loblolly stands 

in the Georgia Piedmont (Brender 1973). Total 

basal area averaged 110 square feet per acre 

with a range of 74 to 134. Stand composition was predominantly loblolly pine. 

Ten shortleaf pine stands were located on 

the Sumter Nati nal Forest in Union County, 

South Carolina.' They averaged 50 years of 

age with a range from 26 to 82 years. Average 

site index (shortleaf at base age 50) was 50. 

Total basal area averaged 91 square feet per 

acre. Variation in site index and total basal 

area was less for shortleaf pine stands than for 

loblolly stands. 

Average radial growth, stem diameter, and 

total tree height was greater for loblolly pine 

than shortleaf pine. This is largely the influence of better site quality. There was little 

evidence of disease problems in the stands. The 

Campbell and Copeland littleleaf rating system 

li he authors thank timber management personnel 

on the Chattahoochee-Oconee and Sumter National 

Forests for providing the information necessary 

to locate and select the study stands. 

classified 57 percent of the stands as moderate 

hazard; the remaining 43 percent were low hazard 

sites. All stands were generally in good 

health . 

Table 1.--Character*istics of lobloiiy and shortleaf pine atends iued to asaevs 

oroun oonditions md related radlal growth 

Varlable Unit Hean Hlnioutir Hax :mars 

__-L--_--------------------------------------------------------*----------------- 

LOBLOLLY PINE 

Herght--pine 

4% 

Site index at 50 years 

D.b.h. pine 

Radial grovth--last 5 years 

Pine basal area 

Herdwood basal area 

Total basal area 

Loblolly 

Shortleaf 

nelght--pme 

Age 

Site index at 50 years 

~.b.h. pine 

Radial grouth--last 5 years 

Prne basal area 

feet 

year= 

feet 

inehea 

nl llmaLers 

ft'/*cr s 

rtZ/acr o 

rt2/(icre 

percent 

percent 

SHOHTLEAF PINE 

feet 

years 

feet 

ineheml Iroretat J h ft,/dci a 

H~rduood basal area ft-/acre 

Total ba~l area ft2/ae: e 

bblolly percent 

C;hortleaf percent __-_-__----------------*----------------- 

106 

67 

98 

78.7 

18.0 

118 

48 

154 

too 

64 

ASsESSING THE EUROPEAN SYSTEM ON SOUTHERN PINES 

The crown rating system developed in Germany 

appears well suited for evaluating tree vigor 

associated with stand and damage conditions in 

European countries. However, the system was not 

particularly adaptable for evaluating the loblolly and shortleaf stands sampled in the Piedmont. Examination of 420 study trees indicated 

no need for assessing foliage color. Degree of 

yellowing was less than 25 percent for all 

trees. Although severe yellowing can occur on 

high-hazard littleleaf sites or nutrient deficient soils, results indicate a careful estimate 

of crown density alone can be used as a reliable 

estimator of tree and stand vigor. 
RELATIONSHIPS BmEm CROWN DENSITU AtrlD 

RADIAL GROW 

There was a general decline in the radial. 

growth of trees as percentage of foliage loss 

increased (fig. 2). Correlations were stronger 

for young stands than for mature and overmature 

stands (table 2). There were little differences 

in correlation values between loblolly and 

shortleaf pines. 

Figure 3 shows a plotting of data pgints for 

loblolly pine stands with the highest r 

value. These plottings show that relationships 

between crown density and radial growth are 

strong for dense and sparse crowns but appear to 

weaken toward the 40 through 60 percent crown 

classes. This relationship was consistent for 

most of the stands sampled. 

Sparse crowns obviously do not contain adequate needle surface area to support good 

growth, whereas dense crowns do. Reliable estimates of the percentage of foliage loss can be 

easily made for these two types of crown 

classes. It is more difficult to estimate crown 

density in the 40 to 60 percent range. Growth 

on these trees is also more likely to be influenced by variation i n s i t e quality and density 

that exists within any given stand. These 

factors--alone or in combination--could account 

for the wide variation in radial growth. 

Percent Fo; lags icii,~ 

Figure 2.--Relative change in radial growth of 

loblolly and shortleaf pines associated with 

percent foliage loss. 

Table 2.--0~rre~ation ostween perlodie radial increment (0-5 years; and erovn 

vigor classlflcatlon, for young and mature lobioiiy wid short?ear pine stands 

Lobiolly pine Shortlaaf plne 

Stand -- - - - - - -- - - -- - - -- 

%a Hean Low Hrgn Men Lou Hlgh 

Young 0.57 0.46 0.73 0.75 0.72 0.80 

LOBLOLLY PINE 

WIAL aownl IN Fn 

0-5 WUS Sfmil 28 

TWO TREES 

Figure 3.--Relationship between crown density 

and radial growth are strong for dense and 

sparse crowns, but weaker toward the intermediate crown density classes. 

5 

0 

Several other correlations were examined. 

Relationships between crown density and tree 

diameters were significant but not as strong as 

correlations between crown density and 0-5 year 

radial growth. Radial increment for 6-10 and 

11-15 years was examined. There was no significant correlation between these two measnzements 

and the current crown vigor class, 

- RG - 3i.m - 2.m tat 

R? - 0.73 

1 , 

The data base was too limited to examine all 

combinations of age, site index, and stand density on crown classes and related growth. Confounding precluded isolating these variables 

independently. As expected, the strongest correlations were for individual stands. Yet, 

there was considerable variation in radial 

growth from stand to stand. For example, a tree 

with 50 percent foliage loss growing in a young, 

sparsely stocked stand would be growing at a 

rate quite different from that of a comparable 

tree growing in a mature, densely stocked stand. 

This means the method would be reliable to estimate radial increment for trees within a stand, 

but problems may result when making comparisons 

0 10 20 30 40 50 CO 70 80 90 100 between stands, 

STAND VIGOR 

Since crown condition influences individual 

tree growth, the distribution of crown density 

classes in stands can be used as an indicator of 

stand vigor and potential productivity. Figures 

4 and 5 show the distribution of crown classes 

in young and mature loblolly and shortleaf pine 

stands. Distribution patterns for the different 

age divisions and forest types are quite different. For loblolly stands, trees tend to group 

around the 40 to 65 percent classes with a 

higher occurrence of trees with sparse crowns in 

older stands. Only a small percentage of loblolly pine trees in the study stands had dense 

crowns. It would be interesting to examine the 
distribution of crown classes in stands treated 

to increase growth (e.g., fertilized and/or 

thinned). We anticipate the distribution would 

be skewed toward dense crown classes. 

For shortleaf pine, trees were fairly well 

distributed from the 20 to 80 percent crown 

classes. Unlike loblolly pine, (1) a large 

percentage of trees in mature stands had dense 

foliage, and (2) a large percentage of trees in 

young stands had sparse foliage. Differences 

between loblolly and shortleaf pines may be 

attributed to site characteristics. Trees with 

aense crowns and good growth may be better able 

to cope with extreme weather conditions, competition and littleleaf disease than trees with 

sparse crowns. Site quality for loblolly pine 

was above average for the region and may not 

have influenced tree survival. 

\ YOUNG STAND5 

/ (20, 21, 27 YEARS) 35 / 

Figure 4.--Distribution of crown density classes 

in young and mature natural loblolly pine 

stands. 

TREES IN SfAND - PERCENT 50 1 

YOUNG STANDS 

0 10 20 50 40 90 60 70 M) SOlW 

GROWN CLASSIRU;I1ON - PERCENT FOUAGE LOSS 

CONCLUSION 

Tree growth is a complicated process. It is 

influenced by age, stand density, site quality, 

pest problems, genetics, and climatic factors. 

Annual or periodic radial growth are reliable 

means of measuring the effects of these variables on the general vigor of individual trees 

and stands. Yet measures of radial growth are 

not always easy to obtain. Some landowners 

object to quality sawtimber trees being bored to 

extract cores. Diameter measurements needed to 

evaluate periodic growth are not always available. It is expensive and time consuming to 

extract and process cores. Results from this 

study indicate careful assessments of crown 

density can be used to determine a relative 

measure of tree growth and vigor for (1) all 

trees in young stands and (2) trees with sparse 

and dense crowns in mature stands. 

Crown density reflects the combined effects 

of branch and shoot development, branch and 

shoot retention, needle retention, and needle 

length. Crown density is a relatively easy 

measure to assess; it is more difficult to 

identify factors that influence this crown 

characteristic. A lack of moisture curtails 

shoot growth, needle length, and loss of 

branches (Copeland 1955). Heritability influences the number, size, and chemical composition 

of branches related to natural pruning. Results 

from this study indicate site quality and age 

are related to crown density. It is also likely 

that competition resulting from dense stocking 

influences needle length and needle retention. 

Many of these tree and stand characteristics can 

be influenced through tree improvement programs, 

stand establishment practices, and cultural 

measures during stand growth and development. 

Crown vigor should be maintained throughout the 

rotation. Poor growth associated with sparse 

crown may be an irreversible condition. 

We do not suggest that crown density be used 

to determine precise measures of potential 

growth and yield. That would be an extreme 

oversimplification. We do conclude that crown 

characteristics can be used to assess the 

general health of individual trees and stands. 

We recommend that foresters examine and consider 

crown conditions when prescribing silvicultural 

treatments. 

Figure 5.--Distribution of crown density classes 

in young and mature natural shortleaf pine 

stands . 
LITmmE CITED 

Anderson, R. L.; Mistretta, P. A. Management 

strategies for reducing losses caused by 

fusiform rust, annosus root rot, and 

littleleaf disease. Agric. Handb. 597. 

Washington, DC: U.S. Department of 

Agriculture; 1982. 30 pp. 

Belanger, R. P.; Hedden, R, L.; Tainter, F. H. 

Managing piedmont forests to reduce losses 

from the littleleaf disease - southern pine 

beetle complex. USDA Forest Service - Cooperative State Research Service Integrated Pest Management Handbook. Agric. 

Handbook 649; 1985. 19 pp. 

Brender, E. V, Silviculture of loblolly pine in 

the Georgia Piedmont. Rep. 33. Macon, GA: 

Georgia Forest Research Council ; 1973. 74 

PP . 

Cambell, W. A.; Copeland 0. L. Littleleaf 

disease of shortleaf and loblolly pine. 

Circ. 940. Washington, DC: U.S. Department 

of Agriculture; 1954. 41 pp. 

Deetlefs, P. P. du T. The relationship between 

stand density, crown size and basal area 

growth in stands of Pinus taeda in the 

native habitat of this species. So. African 

Forestry Assoc. Journ. 24:l-28; 1954. 

Dunning, D. A tree classification system for 

the selection forests of the Sierra Nevada. 

J. Agric. Res. 36:757-771; 1928. 

Grano, C. X. Growth of loblolly pine seed trees 

in relation to crown density. J. For, 

55 : 852 ; 1957. 

Guttenberg, S. Loblolly crown length--clue to 

vigor. South. For. Notes 88. New Orleans, 

LA: U.S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1953 

Hall, R. C. Penalty system for rating high-risk 

trees: eastside ponderosa and Jeffrey pine, 

1951. 1 p. 

Hall, R. C. Sanitation/salvage controls bark 

beetles in southern California recreation 

areas. J. For. 56(1):9-11; 1958. 

Keen, F. P. Relative susceptibility of ponderosa 

pines to bark beetle attack. J. For. 

34 (10) : 919-927 ; 1936. 

Schroter, H.; Aldinger, E. Beurteilung des 

Gesundheitszustandes von Fichte und Tanne 

nach der Benadelungsdichte. Allgem. Forst 

Zeits. 40(18):438-442; 1985. 

Schumacher, F. X.; Coile, T. S. Growth and 

yields of natural stands of the southern 

pines, Durham, NC: T. S. Coile, Inc.; 1960. 

155 PP. 

Schutt, Peter; Cowling, Ellis B. Waldsterben, 

a general decline of forests in central 

Europe: symptoms, development, and possible 

causes. Plant Disease 69 (7) : 548-558 ; 1985. 

Sheffield, Raymond M.; Cost, Noel D.; Bechtold, 

William A.; McClure, Joe P. Pine growth 

reductions in the Southeast. Resour. Bull. 

SE-83; Asheville, NC: U.S. Department of 

Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1985. 112 pp. 

Smith, H. Richard; Wickman, Boyd E.; Hall, Ralph 

C.; [and others]. The California pine riskrating system: its development, use, and 

relationship to other systems. In: Hedden, 

Roy L.; Barras, Stanley J.; Coster, Jack E. 

Hazard-rating systems in forest insect pest 

management: Symposium proceedings. Gen. 

Tech. Rep. WO-27. Washington, DC: U.S. 

Department of Agriculture, Forest Service; 

1981:53-69. 
GELECTION OF SOUTHERN PINE BEETLE HAZARD RATING SYSTEMS FOR MISS ISSIPP 11/ 

C. R. Wonea, T. E. Nebeker, and J. D. ~e~n~eliszl 

Abstract.--Seven southern pine beetle (Dhcdroctonms frglrcjs 

Zimm.) hazard rating systems developed for use in various parts of 

the southeast responded to changing site and stand conditions which 

effect the relative beetle hazard for private nonindustrial pine 

stands in Mississippi. Three of the systems were found to be m6re 

appropriate than the other systems. If radial growth data are 

available or can be obtained, one of two systems developed from 

data collected in Arkansas, Louisiana, and Mississippi is most 

appropriate depending on the level of hardwood control. If 

hardwood competition is maintained at a low level, a fairly simple 

system which uses only pine basal area and radial growth to 

indicate the relative hazard can be used. Stands containing more 

hardwood should be rated with the more complicated of the two 

systems which uses hardwood bgsal area as one of the inputs. If 

large areas are to be rated ajd ground inventory data are neither 

available nor obtainable, a spstem developed in Texas is 

appropriate for use with aerial photographs. 

INTRODUCTION 

The southern pine beetle (SPB), gendfoctonus 

frontalis Zimm., has periodically disrupted timber ------- 

management and the flow of resources from southern 

forests. A major effort has been directed at 

identifying site and stand conditions most 

frequently associated with SPB infestations (Ku et 

al. 1980, Kushmaul et al. 1979, Belanger et al. 

1981). Rating systems have been developed which 

rate stands as to their relative susceptibility ts 

SPB, and in one case ason on 1981) to potential 

losses due to the SPB. These rating systems have 

generally been developed for spec if ic geographic 

areas or from data bases with limited data ,types. 

Although systems have been developed partially 

or entirely with Mississippi data, the data used 

were collected from relatively small port ions of 

the state and may not fully describe the range of 

stand conditions found in Miss issippi. Three SPB 

hazard rating systems were developed by Kushmau 1 

et al. (1979) based on data collected in 

Louisiana, Arkansas, and Mississippi, and a syste+ 

was developed by Sader and Miller (1976) from dat~ 

collected in Copiah Co., Mississippi. It is 

desirable for a system to be validated with the 

full range of expected stand conditions before it 

is recommended for use. Therefore our objective 

11 MAFES Contribution No. 6235, study supported 

by Mississippi Agricultural and Forestry 

Experiment Station and the Mississippi Forestrv 

Commission. 

21 Research Associate and Professor, Department 

of Entomology, Mississippi State University, 

Mississippi State, MS 39762; Assistant 

Entomologist, Department of Entomology, North 

Carolina State University, Raleigh, NC 

27695-7613. 

was to compare the performance of several rating 

systems with pine stands from all Mississippi 

counties which have experienced prob lems with the 

SPB. 

METHODS 

Seven rating systems were selected for 

comparison, and for the sake of simplicity they 

will be referred to by number only (Table 1). 

Different developmental approaches were used with 

each system, and they are based on data from 

various parts of the southeast. Systems 1 and 4 

may be used with generalized site and stand 

information acquired from aerial photographs to 

allow hazard rating on a large number of stands at 

relatively low cost, and system 2 was constructed 

such that it can be used with a minimum number of 

calculations. All seven use data which can be 

obtained from ordinary forest inventory 

informat ion. 

Hazard Classes Generated ------------------ 

Hazard classes (Low, High, etc.) have been 

identified by these systems in various manners. 

Systems 1 and 4 identify five hazard classes, 

systems 2 and 3 have three classes, and systems 6 

and 7 indicate if the stand would be expected to 

be infested or not. The probability of 

infestation is estimated by system 5. These 

various forms of hazard class determination make 

it difficult to compare the systems. We therefore 

altered the interpretation of the score determined 

by systems 2, 3, 5, 6, and 7 to generate five 

hazard classes (very low, low, medium, high, and 

very high) for each system. 
Table 1. --SPB hazard rating systems selected for comparisons. 

------------------------------------------------------------------------------------------- 

System Var iab les Area Where 

,-,,------ 

Number Used Reference ------------------------ ----- ------- EES~~P!~!! ----- ---- --------------- - -- ---- 

1 pine and hardwood basal area Copiah County, MS Sader and Miller (1976) 

average DBH 

2 pine and hardwood basal area Georgia Piedmont Belanger and Price (1979111 

shortleaf pine basal area 

radial growth (last 5 years) 

live crown ratio 

soi 1 type 

pine and hardwood basal area Arkansas 

age 

radial growth (last 10 years) 

pine basal area Texas 

land form 

total tree height 

Ku et al. (1979) 

Mason et al. (1981) 

pine and hardwood basal area Gulf Coastal Plain Hedden ( 1985 121 

landform 

age 

disturbance (lightning or 

logging) 

6 pine basal area Arkansas, Louisiana, Kushmaul et al. (1979) 

radial growth ( last 10 years) Mississippi 

7 pine and hardwood basal area Arkansas, Louisiana, Kushmaul et al. (1979) 

age Mississippi 

number of trees per acre 

site index 

11 Belanger, R. P., and T. S. Price. 1979. The susceptible forest in the upper Piedmont. 

Fact Sheet. Ga. For. Comm., Macon, Ga. and U.S. Dep. Agric. For. Serv., Southeast. For. Exp. 

Stn., Asheville, NC. 1 p. 

2/ Hedden, R. L., and R. P. Belanger. 1985. Predicting susceptibility to southern pine beetle 

attack in the Coastal Plain, Piedmont, and southern Appalachians. Integrated pest management 

symposium proceedings. U.S. Dep. Agric. For. Serv. Gen. Tech. Rep. SO-56. 

System 2 consists of six questions which are 

answered "yes" or "no"; the number of questions 

answered "yes" is used to indicate the relative 

hazard. One of the questions deals with the 

presence of micaceous red clay which does not 

occur in Mississippi, therefore the question was 

omitted. The remaining five questions were used 

,as follows: 

5 "Yes" answers = Very High Hazard 

therefore the range of probabilities was divided 

to create 5 hazard classes (Table 2). 

Five hazard classes were identified for systems 

3, 6, and 7 by dividing the range of discriminant 

scores (XI into five intervals (Table 2). These 

interva 1s were derivpd by calculating the mean 

discriminant score (XI and standard deviation (s) 

of 62 infestations and setting the break points at 

X t .5s and X 2 1.0 s. Hazard classes were 

assigned for the resu lt ing in terva 1s as £01 lows : 

4 "Yes" answers = High Hazard 

Very High = X < (% - 1.0 S) 

3 "Yes'bnswers = Medium Hazard 

2 "Yes'\nswers = Low Hazard 

1 or 0 "Yes" answers = Very Low Hazard 

In order to calculate the probability of 

infestation with system 5 an estimate of the 

number of SPB infestations per 1000 acres of host 

type is required. This information was not 

available for the data used for these comparisons, 

High = (2 - 1.0 s) (X< (2 - .5 s) 

Medium = (% - .5 s) ( X < (x + .5 s) 

Low = (X + .5 s) ( X < (X + 1.0 s) 

Very LOW = x > (% + 1.0 sj 

Altering the number of classes calculated by 

these systems changes the distribution of ratings 
Table 2.--Generated hazard classes for systems 3, 4, 6, and 7. 

Eazard-claza S~stem 3 Sxstem 4 System 6 System 7 ---------- ------------------ ---------------- ------------------- --------- 

Very High (-41.37 >0.8 (-1.23 (-1.2 

High -41.37 to -6.0 0.6 to 0.79 -1.23 to -.85 -1.2 to -.68 

Med ium 

Low 64.77 to 100.14 0.2 to 0.39 -.08 to .28 -37 to .89 

Very Low > 100.14 <O. 2 >.28 >.89 

for a given set of pine stands, but the median of 

the distribution is changed only slightly. It 

could be argued that these alterations essentially 

create a system other than the one originally 

presented. This is of little concern because the 

objective of this study is to identify a system or 

systems which will indicate the relative SPB 

hazard for Mississippi pine stands. It is not 

intended to necessarily validate an existing 

system for use in the state, therefore the results 

should not be used to judge the value of any one 

of these systems in other areas without careful 

considerat ion. 

Data Used For Com~arisons ----------------- ------- 

Four general data types were used for these 

comparisons. Information required by the selected 

systems is contained in data collected in 

Mississippi which represent the following data 

types: 

1. The general population of loblolly and 

short leaf pine stands. 

2. Loblolly and short leaf pine stands which 

contain recent SPB infestations. 

3. SPB infestations which occurred during low 

SPB popu lat ion leve 1s. 

4. SPB infestations which occurred during high 

population levels. 

Mississippi Forestry Commission crews collected 

data from 511 private nonindustrial forest stands 

which were used to represent the general 

population of pine stands by placing one prism 

plot per five acres throughout each stand. Stands 

were selected from all counties which had 

experienced significant SPB infestations; at least 

ten stands were rated in each county. Stands were 

delineated using aerial photographs by homogeneity 

of timber type, age, and ownership. These stands 

were at least 204 pine with no restrictions placed 

on age, origin, disturbance, or SPB activity (past 

or present). The seven rating systems were used 

with the five classes described above to rate each 

sample point, and to rate the stand based on 

average stand parameters. 

Stands with SPB activity within the last year 

(data type two) were located in 1983 with help 

from Mississippi Forestry Commission personnel. 

Once located, Mississippi Forestry Commission 

crews delineated and collected data on these 

stands as previous ly described . These 124 stands 

were rated in the same manner as those above. 

Infestations which were found in the stands with 

recent SPB activity were used to represent the 

third data type because the SPB population was 

relatively low in 1983. Data for these 111 

infestations were collected by placing a prism 

plot at the origin. This prism plot was in 

addition to those used for the stand as a whole. 

Data were collected on 62 SPB infestations for 

the site/stand working group of the Expanded 

Southern Pine Beetle Program in 1977. These 

infestations occurred when the SPB population was 

high, therefore they will be used to represent the 

fourth data type. Most of the infestations were 

located in the Tombigbee National Forest and the 

Noxubee Wildlife Refuge with a few located in the 

Homochitto National Forest, and they ranged in 

size from 2 to 1050 infested trees. 

It is necessary to define desirable traits for 

the system which will be used in order to make 

meaningful comparisons. Since the hazard rating 

for a stand indicates the hazard relative to all 

other pine stands, the distribution of the ratings 

for all pine stands is expected to be normally 

distributed with most stands in the "medium" 

class. The system must be able to indicate stands 

which are more likely to lose trees to SPB if 

infestations occur. This does not mean all stands 

with infestations would be rated "high" or "very 

high". Most of these stands which have 

infestations will be rated "medium" because of the 

total number of stands in this class, and some 

will be rated "low" or '"very low". Disturbance 

(i.e. - lightning or logging) leads to some of the 

infestations in these lower rated stands, and 

small areas of high tree density within the stands 

can become infested. However, the distribution of 

ratings for stands which have infestations is 

expected to be skewed to the higher classes, and 

the number of trees killed per acre of host type 

is expected to increase as the rating increases 

(Mason and Bryant 1984). The distribution of 

ratings for the infested "spots" is expected to be 

skewed even more to the high classes. 
Additionally, variables which can be measured 

easily in normal timber inventory procedures 

should be employed by the system and each 

variable's effect on the hazard rating should be 

consistent with trends observed in the area of 

intended use. Sufficient ear iab les should be used 

to allow the hazard rating to be sensitive to 

silvicultural practices such as hardwood control 

and thinning if they could be used to lower the 

hazard rating . 

Statistical analysis can aid in these 

comparisons by indicating quantitative differences 

between systems. Pairwise comparisons were made 

using numerical rating classes (very 10~~1,0~12, 

medium-3, high-4, very highs51 with a sign test 

which ignores the magnitude of the differences; 

the test determines if the ratings from two 

systems have the same median (conover, 1971). 

RESULTS 

Many differences can be observed by comparing 

the hazard ratings produced by these seven systems 

from the four data sets. Pairwise comparisons 

among the rating systems indicate significant 

differences between systems with each data set. 

The ratings from system 7 have higher overall 

medians than the other six systems, and the 

ratings from systems 6, 3, and 4 have higher 

medians than do systems 1, 2, and 5 (Table 3). 

Table 3.--Sign test results. 

------------------------------------------------- Hazard rating systems ranked by 

median numerical rating -------------- ----------------------------------- 

Med i an 

rank GPS! ----- SRA~~ ---- ILP~/ ----- I HP&/ 

Highest 7 a* 

Lowest 1 e 2 c 2 c 1 c 

* Systems followed by the same letter do not 

have significantly different medians (pC.05). 

1/ GPS - general population of pine stands 

z/ SRA - stands with recent SPB activity 

31 ILP - infestat ions during low SPB population 

$1 IHP - infestations during high SPB population 

Hazard ratings from systems 3, 6, and 7 for the 

general population of pine stands in Mississippi 

are approximately normally distributed, while the 

distribution of ratings from systems 1, 2, 4, and 

5 tend to be skewed toward the lower hazard 

classes (Figure I-A). The ratings for stands with 

recent SPB activity are distributed generally in 

higher classes than are the ratings for the 

general population of pine stands for all of the 

systems (Figure 1-B), the ratings for the 

infestations located in these stands are 

distributed in even higher classes (Figure 1-6). 

Movement of the distribution of ratings to higher 

hazard classes as the data type changes from the 

general population of stands, to stands with 

recent activity, and to the actual infestations 

indicates that all of the systems are responsive 

to changing stand conditions which create more 

hazardous conditions. 

It appears that the need for hazard rating in 

Mississippi can be met by using one of three 

systems. The decision of which one to use depends 

on available data, approach to data collection, 

and level of hardwood control. Systems 6 and 7 

offer a distribution of ratings for the various 

data types which is very close to those expected, 

and the variables in these systems are used in a 

manner consistent with trends observed in 

Mississippi. The distributions of ratings from 

system 4 are slightly less desirable, but this 

system uses variables which can be estimated from 

aerial photographs. One of the variables used by 

system 4 is landform with three classifications 

!ridge, side slope, and bottom) none of which 

accurately describe the f latwoods area of 

Mississippi; for this comparison the flatwoods 

were classified as "bottom". These disadvantages 

with system 4 would easily be outweighed by the 

convenience and economics of using aerial 

photographs if ground inventory data were not 

available and large areas with numerous stands 

were to be rated. Systems 6 and 7 require data 

which can only be collected on the ground, but it 

is data that would be collected in normal 

inventory practices required for more intensive 

management decisons. System 6 is relatively 

simple since it uses only pine basal area and 

radial growth to calculate the hazard rating; this 

system would be most appropriate where hardwood is 

controlled well enough to offer little competition 

for the pine. System 7 is more complicated than 

the other two systems, but it offers more 

flexibility in the manner in which stand 

conditions can be manipulated to lower the hazard 

rating since more stand parameters are used. 

Therefore, system 7 would be more appropriate for 

stands with larger hardwood densities. 

DISCUSS ION 

It is necessary to define the intended use of a 

hazard rating system before its performance can be 

evaluated. Ideally the system would indicate 

which stands will have large enough losses within 

some time frame to justify treatment. However, 

predictions of this nature on a stand basis may 

not be obtainable. Pine timber management is 

complicated by many factors which should be 

considered in order to meet the objective for 

growing trees - whether financial or aesthetic. 

Potential loss to the SPB is only one of these 
HAZARO CLASS 

Figure 1.--Distribution of hazard ratings (VL-very low, L-low, M-medium, H-high, VH-very high) for seven 

southern pine beetle hazard rating systems (1-7) used with four data types (A-general population of pine 

stands, B-stands containing recent SPB activity, C-infestations during a low SPB population level, 

D-infestations during a high SPB population level) in Mississippi. Percentages (%) are the proportion of 

stands or infestations (spots) placed in a hazard class by one of the seven systems divided by the total 

number in the data type, therefore the sum of the points on each line should total 100. 

considations. Taking action to reduce a high SPB 

hazard without considering other factors is not 

advisable. Harvest and thinning schedules should 

be established for a pine stand by considering 

all of the important factors, and the schedule 

should not automatically be altered due to a high 

hazard rating. Obviously there is little risk of 

incurring substantial losses if the SPB population is extremely Low regardless of the hazard 

rating. Hazard ratings can be used to identify 

stands for xhich it may be advantageous to alter 

harvest or thinning schedules by indicating the 

SPB hazard relative to all other stands. They 

can also be used to assign a priority to several 

stands which are in need of treatment or to stands 

which have SP3 infestations in need of control. 

All of the systems place more of the "spots" 

which were infested during high levels of the SPB 

pop~lation into the lower classes (Figure 1-D) 

than the spots which were infested during low 

levels (Figure 1-C). Few stands are safe from the 

This does not mean that hazard ratings are 

invalid during epidemics, because most of the 

losses will be contained in the stands rated 

"high" and "very high. " 

Rating individual sample points and dividing the 

stand or forest ownership into areas of similar 

hazard might be preferable to identifying a stand 

and rating the stand based on average stand 

conditions. Defining stand boundaries from aer~a; 

photographs or ground surveys can he difficult. 

Rating each sample point may not be practical if 

the calculations are done by hand. However, if a 

computer or programmable calculdtor is used for 

stand analysis and the data are recorded for each 

sample point, the stand division by hazard class 

is feasible. After the areas of common hazard are 

identified, it would be necessary to determine if 

there is a large enough area with conditions 

sufficient to justify altering harvest or thinning 

schedules. 

S?B during severe outbreaks, therefore the 

distribution of ratings for the infestations moves The quality of stand management should not be 

back toward the lower classes during these periods. judged by the hazard rating for the stand. Poorly 
managed stands can be overstocked due to lack of 

attention or mnagement objectives other than 

financial gain, or they can be understocked with 

pine due to excessive cutting or lack of hardwood 

control. Intensively managed stands will have 

proper stocking, and they kill have conditions 

which will put them into the high rating classes 

before they reach economic maturity. Therefore, a 

high rating does not necessarily indicate improper 

management, and a low rating may not indicate a 

well managed stand. 

Although the SPB can be very devastating, 

forest management should not be based entirely on 

eliminating losses from this one pest. Hazard 

rating has a place in forest management by 

identifying areas with high hazard to the SPB, 

relative to all other pine areas, where it may be 

advantageous to alter the harvest or thinning 

schedule . 

Acknowledgements: The authors wish to thank 

Bill Lambert of the Mississippi Forestry 

Connnission for his special assistance during the 

data collection phase of this study. We also wish 

to thank the many forestry students who 

participated in the data collection. 

LITERATURE CITED 

Belanger, R. P., R. L. Porterfield, and C. E. 

Rowell. 1981. Development and validat ion of 

systems for rating the susceptibility of natural 

stands in the Piedmont of Georgia to attack by 

the southern pine beetle . In: Hazard-rat ing 

systems in forest management. Sym. Proc. U.S. 

Dep. Agric. For. Serv. Gen. Tech. Rep. WO-27 

pp. 9-12. 

Conover, W. J. 1971. Pfacti~gl bn~afam$ffL~ 

Statistics. John Wiley & Sons. pp, 121-127. -------- 

Ku, T. T., J. M. Sweeney, and V. B. Shelburne. 

1980. Site and stand conditions associated with 

southern pine beet le outbreaks in Arkansas -a 

hazard-rating system. Southern Journal of 

Applied Forestry. 4(2):103-106. 

Kushmaul, R. J., M. D. Cain, C. E. Rowel1 [and 

others]. 1979. Stand and site conditions related 

to southern pine beetle susceptibility . Forest 

Science . 25: 656-664. 

Mason, G. N., and C. M. Bryant V. 1984. 

Establishing southern pine beetle hazard from 

aerial stand data and historical records. Forest 

Science. 30( 2) : 375-382. 

Mason, G. N., R. R. Hicks, Jr., C. M. Bryant V. 

[and others]. 1981. Rating southern pine beetle 

hazard by aerial photography. In: R. L. Hedden, 

S. J. Barras, and J. E. Coster, eds. Hazard 

rating systems in forest insect pest management: 

symposium proceedings. U.S. Dept. Agric. For. 

Serv. Gen. Tech. Rep. WO-27. pp. 109-114. 

Sader, S. A., and W. F. Miller. 1976. Development 

of a risk rating system far southern pine beetle 

infestations in Copiah County, Mississippi. In: 

Remote sensing of earth resources. NASA. Vol. 5, 

pp. 277-294. 
EFFECT OF F?FSZFOPSI RUST ON StTRVfVAT, OF T,ORI,OT,LIJ PINE 

lJarren L. EJance and Eugene ~houlders_l/ 

Abstract.--The probability of survival for individual 

trees with and without fusiforn rust sten cankers are 

compared using data from a large, long-term study of 

loblolly pine (Pinus taeda Id,). The comparisokts reveal a 

dramatic reduction in probabilfty of survivai for trees 

infected with fusifom rust stem cankers co-pared to their 

uninfected neighbors growing in the sane stand under sinilar 

conditions. The probability of survival for trees with stem 

cankers is shown to be affected by the age of the tree when 

first infected with a stem canker, the tree's conpetitive 

status within the stand, and the tree's age, The various 

probabilities of infection, survival, and death in these 

data are sunnarized. The results of this investigation are 

briefly compared to those fron a sinilar study of slash pine 

(Pinus elliottii Ei~p~ln. 1, and several nanagement and 

nodeling complications introduced by tlkc disease are 

discussed. 

INTRODUCTIOPJ THE STUDY 

Previous investigation of the slash pine 

portion in a site-species trial revealed that 

slash pine trees infected with fusifom rust sten 

galls had a much lower probability of survival 

than gall-free neighbors. An infected tree's 

probability of survival was related to the tree's 

relative size (competitive status) and age when 

first infected with a sten canker (Nance and 

others 1981). 

The frequency of sten cankers and the 

probabilities of survival for individual 

sten-galled and gall-free loblolly pines fron the 

sane species-site trial are reported in this 

naner. The results for loblollv nine (Pinus E 3 , s 

taeda L.) are conpared with those fron the slash 

nine (Pinus elliottii Fn~eln.) ort ti on of the 

study. 

l/paper presented at Southern Silvicultural - Research Conference, Atlanta, Ceorgia, November 

4-6, 1386. 

21~rincipal Plant Geneticist and Principal 

~ilvicul turis t, USDA-Forest Service, Southern 

Forest Experiment Station, Gulfport, ITS, and 

Alexandria, LA, respectively, 

In the study, three plots of each of three 

species (loblolly, slash, and longleaf pine 

(Pirius- palustris 1.1111.)) were planted in a 

randomized block design on uniform sites at 113 

locations in Louisiana and Flississippi in the 

1950's (Shoulders 1976), At age 20, there 

renained 146 loblolly pine plots (88 in Louisiana 

and 58 in Elississippi) at 60 locations with 

little or no fire, insect, or disease damage 

other than fusifom rust. All plots had been 

inventoried at identical ages: i.e., after 3 

(Ilississipni plots) or 5 (Louisiana plots), 10, 

15, and 20 years. Each of these inventories 

provided individual-tree data on tree size and 

incidence of stem galls. Data fron these plots 

were pooled to deternine probability of survival 

or death, over tine, of trees with and without 

one or more sten palls. Probability was further 

partitioned according to the tree's relative 

size, competitive status, and, for sten infected 

trees, the tine in the tree's life that the first 

infection occur red ( Shoulders and Nance 1986) . The loblolly pine seedlings planted in each 

state were grown from seed lots collected in that 

state. For slash pine, nost of the installations 

(nore than 80 perctant) were grown from seed 
collected in southern Hississippi and the 

adjacent parishes fn southeastern Louisiana where 

slash pine is indigenous. Seed for the remaining 

installations, all in Mssissippi, were obtained 

frm a Georgia seed dealer, Their exact 

geographic origin is unknmI, 

CmIULATIVE RATES OF STEfl IWFECTION 

In mssissippi, 35 percent of loblolly trees 

hat were present at age 3 developed one or more 

ten ~alls by age 20 (fig, I). Infection levels 

for loblolly pine were much lower in Louisiana 

than in tiississippi, averaging only 11 percent at 

20 years for trees that were alive at 5 years, 

This difference in infection levels between 

the two states in the loblolly pine portion of 

the study was surprising in view of the fact that 

the infection levels at age 20 for the slash pine 

portion of the study were essentially the same 

for both states (27 percent in lfississippi and 26 

percent in Louisiana). Careful inspection of the 

data showed no differences in infection levels 

between the two sources of seed used to establish 

the slash pine installations. 

STEtf-GALLED TREES 

Since a tree's competitive status in the 

stand affects its ultinate fate, the trees in 

each state were partitioned into four height 

groups to study the probability of stm-galled 

trees to survive. The partitionfng was 

acconplished by the followinp nethod. All trees 

within a plot were ranked according to height at 

3 (Hississippi) or 5 (1,ouIsiana) years without 

regard to their disease status. Each of these 

plot arrays was then subdivided into four groups 

of eaual slze with heipht group 1 containing the 

shortest one-fourth of the trees and height group 

4 containing the tallest one-fourth. Finally, all 

trees within a state were pooled according to 

group position, and transitional probabilities 

were cmptsted for each of the four height grotlps 

(Trance and others l.381). 

In both states, the survival probability of 

sten-galled lohlolly pine trees increased as the 

ape when the pall was formed increased and as the 

tree's cmpetitive position in the stand improved 

(figs. 2, 3), Th~re were, however, inportant 

diff ererrces hetween states in tile way the disease 

affected survi-~al of trees in individual height 

protlps. 

For IobloLly pines hn the tallest heipht 

group, the probahilfty for sten-galled trees to 

survive was always higher In the Louisiana than 

in the Elississippi population (fig, 2). This 

trend, together with the higher probability of 

infeetlon in the Pussissippi plots, resulted in 

heavier natural thinning from above in the 

Mississippi than in the Louisiana installations. 

A further consequence of this difference in 

rust-associated mortality in the tallest height 

group was that trees in the shortest height group 

were subjected to greater conpetitive stress at 

an early age in Louisiana than in Nississippi. 

Consequently, after age 10 the probability of 

survival among stem-galled trees in the shortest 

height group was lower in Louisiana than in 

ffississippi* 

While trends were in the sane direction, 

tree size had less effect on the probability for 

slash pine to survive with a stem gall (fig, 3). 

In the tallest height group, the probability for 

stem galled trees to survive was greater for 

loblolly than for slash pine. In the shortest 

height group, when stem galls were present, 

infected slash pine tended to survive longer than 

loblolly pine. The difference between the two 

species in persistence of trees in the shortest 

height group probably reflects a difference in 

the way the species respond to competitive 

stress. 

As was the case with loblolly, the 

probability was greater in Louisiana than in 

Mississippi installations for stem-galled slash 

pine in the tallest height group to survive. But 

the difference between states was mch less 

pronounced in slash than in loblolly pine. 

DISCUSSION AND CONCLUSIONS 

The design of this experiment provided a 

uniaue opportunity to compare fusiform rust 

infection and transitional probabilities for 

unimproved slash and loblolly pine planted at the 

sane tine on the sane sites across two states. 

In tlississippi, the differences between the 

two species, both in infection level and 

probability of death with a stem canker, were 

auite small. One would find it difficult if not 

inpossible to distinguish between the two species 

with respect to these traits. 

However, the data from the Louisiana plots 

show large differences between the two 

species--with loblolly pine exhibiting much lower 

infection levels and probabilities of death with 

sten cankers than slash pine. Eloreover, the slash 

pine in Loitisiana was renarkably similar in 

infection levels and probabilities of death to 

the slash pine (and loblolly pine) populations in 

Mississippi. 

Although there are many possible 

explanat ions for these results, the nost 

plausible explanation is that the Louisiana 

source of loblolly pine used to establish the 

plots in Louisiana was genetically resistant to 

fusifom rust, whereas the PUssissippi source of 

lo5lolly pine used in the Mississippi plots, as 

well as the slash pine used in both states, was 

not resistant to the disease. This explanaeion 

would be consistent with the rust resistance 

patterns described for provenances of loblolly 
and slash pine reported previously by \Tells and 

liakeley (1966). 

LITERATURE CITED 

If genetic resistance did in fact result not 

only in lower infection levels but also in lower 

probabilities of death for trees with sten 

cankers, then the benefits of using genetically 

resistant material in high rust hazard areas 

would be twofold: the resistant trees would not 

only resist infection better than susceptible 

trees, but those resistant trees that did become 

infected with sten cankers would tend to survive 

hetter with the disease than sinilarly infected 

suscent ible trees. 

Vast authors have assuned that the growth 

and yield benefits attributed to the use of 

genetically resistant planting stock can be 

nodeled by sinply lowering the infection levels 

for resistant stock compared to those expected 

for susceptible stock. The probehility of death 

with a canker is then assuned to be the same 

for resistant and susceptible trees alike. 

Clearly, if the probability of death with a 

canker is lower for resistant trees, this effect 

would also have to be incorporated in any 

assessnent of the benefits attributed to the use 

of resistant planting stock. 

It should be emphasized that the data 

presented here nerely suppests, and cannot 

provide a test of the hypothesis, that genetic 

resfstance offers the dual benefits of lower stem 

infection levels and lower probabilities of death 

with stem cankers. Flore definitive data sets in 

which genetic resistance was a controlled feature 

of the experinent should he available to allow a 

test of the hypothesis. 

llance, FI. L.; Froelich, Ronald C.; Shoulders, 

Eugene. Effects of fusifom rust on survival 

and structure of FZississippi and Louisiana 

slash pine plantations. Res, Pap. SO-172. 

New Orleans, LA: U.S. Department of 

Agriculture, Forest Service, Southern 

Forest Experinent Station; 1981. 11 p. 

Shoulders, E. Site characteristics influence 

relative perfomance of loblolly and slash 

pine. Res. Pap. SO-1 15. New Orleans, LA: 

U.S. Departnent of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

1976. 16 p. 

Shoulders, E.; Nance, I?. L. Effects of fusifom 

rust on survival of loblolly pine plantations. 

Res. Pap. SO- . I?ew Orleans, LA: 

U.S. Department of Agriculture, Forest 

Service, Southern Forest Experiment Station; 

(in press) 

Wells, O. 0.; Ilakeley, P. C. Graphic variation 

in stlrvival, growth, and fusifom rust 

infection in planted loblolly pine. , 

ilashington, D.C. : Society of American 

Foresters, Forest Science Monograph 11; 

1966. 40 p. 

AGE (YEARS) 

Figure 1.--Crxnulative stem gall fornation rates for loblolly and slash pine in tlississippi and 

1,otlisiana species trials. 
MISSISSIPPI POPULATION LOUISIANA POPULATION 

AGE (YEARS) AGE (YEARS) 

Figure 2.--Probability for survival sf hbblolly pine trees with stm-pells by location, age at 

time of detection, and competitive status. 

MISSISSIPPI POPULATION LOUISIANA POPULATION 

5 10 15 2 0 

AGE (YEARS) 

Figure 3.--Probability for survival of sla 

of detection, and competitive status. 

AGE (YEARS) 

ne trees with stem-galls by location, ape at tine 
QUANTIFYING THE EFFECTS OF FUSIFORM RUST ON TREE BASAL AREA 

2 / M, Michael Harrison and L. V, PienaarRemeasurement data from slash pine (Pinus elliottii Engelm.) plantations 

in the Georgia, North Florida, and South Carolina coastal plain were used to 

compare the basal area growth of trees with and without Cronartium stem 

cankers (Cronartium fusiforme Hedgc. and Hunt ex Cumm). Analysis indicated 

that trees without stem cankers grew significantly more than comparable 

infected trees. A general distance-independent individual-tree basal area 

growth model was developed from permanent plot data remeasured over a nineyear period. The use of this equation for growth prediction purposes is 

demonstrated for hypothetical stands with various levels of Cronartium stem 

infections. 

INTRODUCTION 

Fusiform rust, caused by the fungus 

Cronartium fusiforme (Hedgc. and Hunt ex Cumm.), 

is the most serious disease of the southern pines 

(Cowling et al., 1977, Jones, 1972), The most 

widely planted species in the southeast, slash 

pine (pinus elliottii Engelm.) and loblolly pine 

(Pinus taeda L,), are also the most susceptible 

species to fusiform rust (Zobel and Zoerb, 1977). 

Studies relating fusiform rust infection to 

the growth of individual trees have produced 

mixed results. Dell and Driver (1963) studied' 

the diameter distributions of slash pine trees 

with and without stem cankers in the same stand. 

Their data showed that the average diameter of 

cankered trees was not significantly different 

from that of healthy trees and the diameter 

distributions were similar. Barber (1961) 

compared the sizes of healthy and infected trees 

several years after infection and found no 

significant differences. Froelich et al, (1983) 

found that early stem infection and more than 50 

percent encirclement by rust of the main stem 

were required for significant decreases in height 

growth by the end of the sixth growing season 

after planting. In a study of slash pine plantations in South Carolina and Georgia, Powers 

et al, (1974) showed that the growth of severely 

infected trees was significantly reduced. Sluder 

(1977) found significant differences in mean 

volume per tree between stems with and without 

fusiform cankers. The average decrease in volume 

for cankered slash pine stems was 18 percent. 

Jones (1972) investigated height and diameter 

growth of infected and uninfected slash pine. He 

found that the growth of uninfected trees from 

age 6 to 16 was 6.8 percent greater in diameter 

-1' Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 4386. 

- Research Technician 111 and Professor 

respectively, School of Forest Resources, 

University of Georgia, Athens, GA 30602. 

and 7.8 percent greater in height than growth of 

infected trees over the same period. Neither of 

these differences was statistically significant. 

In a study of the effects of fusiform rust on 

growth of planted slash pine in Louisiana, trees were grouped into severity-of-infection classes. 

No significant differences in average dbh, height, 

and voiume per tree were found between uninfected 

trees and trees with stem cankers extending less 

than halfway around the bole. Significant differences were found between trees with 50 percent 

or more of the circumference affected by rust and 

those with less than 50 percent of the stem circumference affected (Burns and Hu, 1985). 

DATA COLLECTION AND SUMMARY 

To compare the growth of infected and 

uninfected slash pine trees, we used data from the 

University of Georgia's Plantation Management 

Research Cooperative Cronartium study. During 

the summer of 1976, 206 permanent plots were 

established in the flatwoods regions of South 

Carolina, Georgia, and North Florida. The plots occur across a wide range of initial planting 

densities, site indeces, ages, and Cronartium 

infection levels (Tables 1 and 2). The plots were 

remeasured every third summer since 1976. The 

last measurement was made in 1985, The 1976 and 

1985 data from 137 plots were used in this study. 

The nine-year data were summarized to show 

differences between surviving trees with and 

without stem infections, regardless of the 

apparent severity of the infection. The average 

dbh of the uninfected trees was larger than the 

average dbh of the infected trees on 36 percent of 

the plots in 1976 and on 54 percent of the plots 

in 1985. Uninfected trees showed an increase of 

2.05 inches in quadratic mean diameter over the 

nine year period compared to a 1.84 inch increase 

in quadratic mean diameter for the infected trees. 
Table 1. Distribution of sample plots by ye in 

1976 and base age 25 site index.- 

Age (years) 

Site index 

(feet) 5-10 11-15 16-2 1 

number of plots 

Table 2. Distribution of sample plots by number 

of trees per acre and percent rust 

infection in 1976. 

Percent rust infection 

Trees per number of plots 

acre 

278-400 2 11 7 3 1 

STATISTICAL TESTS 

Three statistical tests on the null hypothesis that uninfected and infected trees grow the 

same were done. 

-- Paired t-test 2 

Average increases in basal area for 

uninfected and infected trees were calculated for 

each plot and were regarded as paired observations, The mean difference in basal area 

growth (uninfected minus infected) was positive 

and significantly different from zero at the 

a = .05 level. 

Analysis of covariance 

To account for the effect of variability in 

initial tree basal area on basal area growth, an 

analysis of covariance was used to compare the 

growth of uninfected and infected trees, The 

analysis of covariance model is 

Yij = p + si + y (xij -3 + e 

i j 

where yij = Basal area growth for the j t h 

tree, infection level i, 

3' Site index values were calculated uslng 

the equation developed by Newberry and Pienaar 

(1978). 

= overall mean basal area growth, 

si = effect of infection level i, 

x = initial basal area of the j t h 

ij tree, infection level i, 

- 

x = mean initial basal area, 

y = constant multiple effect of the 

amount by which the lnitial size 

x djffers from the mean initial 

sQe x, 

eij = random error component associated 

with y ij ' 

i = 1 if tree was uninfected, 

2 if tree was infected, 

ni = the number of observations at 

infection level i. 

The effect of Cronartium infection (s ) is i obtained by adjusting the means of the y,.'s, the 

adjustment depending-on the means of theL& . 's. 

The t-test for the adjusted means must accdant for 

sampling error arising from the estimation of y. 

The difference between the adjustment means is 

written g, - g2- ;( R, - 22) 

and the variance of this quantity is 

The estimate of G;.~ is the mean square error 

from the regression of y on x (Cochran and Cox, 

1950, Draper and Smith, 1981, Searle et al., 

1980). 

T-tests were done for all plot averages and 

for nine combinations of age in 1976 and site 

index (Table 1). For the plot averages, uninfected 

trees had significantly better growth at the a = 

.05 level. For the site/age classes, uninfected 

trees had a greater least squares mean basal area 

growth in each category. This difference was 

significant in two categories, age 10 and under 

with site index from 55 to 65 feet and at age 

11-15 with site index below 55 feet. 

--- Paired t-test I1 

To further minimize the effect of differences 

in initial tree size on growth, an additional paired 

difference test was devised. Uninfected trees 

were paired with infected trees having the same 

dbh in 1976. These pairings were done within 

plots to minimize the effect of variability in 

growing conditions on growth. The mean difference 

(uninfected minus infected) from 217 pairs was 

positive and significantly different from zero at 

the a = .05 level. Uninfected *trees grew more 

than infected trees of the same initial size on 

the same plot. 
MODEL DEVELOPXENT 

With data from 2227 trees, a linear model 

was developed to predict individual-tree basal 

area growth, \Variables included in models 

developed by Daniels (b981), Alder (1979), and 

others were considered for this analysis. Their 

models could not be used in their entirity, 

however, as they were either distance-dependent 

or contained variables not available from common 

forest inventories. 

Correlation coefficients were calculated to 

decide which variables and transformations of 

variables were linearly correlated with basal 

area growth. The natural log of basal area growth 

was not as highly correlated with independent 

variables as basal area growth or square root of 

basal area growth. The correlation coefficients 

for these two variables were nearly equal for 

each independent variable. Square root of basal 

area growth was chosen as the dependent variable 

to insure nonnegativity of growth estimates. 

Candidate independent variables were used in 

various combinations to predict square root of 

basal area growth. Models with and without 

intercept terms were fit to the data. We found 

that a model without an intercept term could 

better reflect the differences in growth between 

unirlf ected and infected trees. 

The model chosen as the best for basal area 

growth prediction is 

where GBA = square root of nine-year basal 

area growth, 

dbh/A = dbh divided by age in 1976, 

BA/~X = tree basal area divided by plot 

mean basal area, 

B = basal area per acre in 1976, 

sin-' 4s = arcsine of the square root of 

the proportion of trees with 

stem cankers on a plot in 1976. 

Since the hypothesis that trees infected 

with Cronartium grow less than comparable 

uninfected trees was substantiated by the testing 

procedures discussed earlier, dummy variables 

were introduced into the model. Dummy variables 

are variables that take two or more distinct 

levels as opposed to regular independent variables which can take values over some continuous 

range. Dummy variables are assigned levels to 

account for the fact that factors represented by 

the different levels have separate deterministic 

effects on the response variable (Draper and 

Smith, 1981). The dummy variable in this 

analysis is 

Z = 0 for trees not infected with Cronartium 

stem cankers 

1 for trees infected with Cronartium 

stem cankers. 

The dummy variable model is 

Ga = ;p, + P,,z) (dbhi~) + (p, + p,,~) (BAIB~) + 

An F-test was used to determine that a significant improvement in residual sum of squares 

was obtained by inclusion of the dummy variables 

to account for differences in growth between 

uninfected and infected trees. 

F-tests on partial sums of squares were used 

to decide which, if any, coefficients were not 

significantly different from zero at the a = .05- 

variable coefficients for BA/BA, ;v;; s;!~ldu~ NF/ were not significantly different from zero and were removed from the model. 

The model for predicting the growth of uninfected 

and infected trees is 

=A = ((p, + B.,Z) (dbhiA) + B, (B-3) + P, (B) + 

Least squares estimates of the coefficients are 

The R' value is .578 with a mean square error of 

0.0061. Figure 1 shows the predicted growth of an 

individual uninfected tree and an infected tree of 

the same initial size in a hypothetical stand. 

DBH (inches) 

1°1 

AGE (years) 

Figure 1. Dbh over age for individual trees in a 

stand with 55 sq.ft./acre of basal area 

and a 40% infection rate at age 10 

years, 

To demonstrate the utility of this model for 

growth prediction purposes, it was applied to hypothetical stands with 400 and 805 stems per acre 

at age 10 and various levels of Cronartium stem 

infections. Age 10 stand tables taken from Bailey 

et al. (1982) for site-prepared slash pine plantations were used for this purpose. Mortality 
rates for uninfected and infected trees were calculated with equations developed by Clutter and 

Devine (1982). A FORTRAN program was written to 

simulate the development of the stands and output 

age-20 stand tables. Infection rates of 0, 20, 

40, 60, and 80 percent were applied to each stand. 

With an initial density of 800 stems per acre, 

total basal area per acre at age 20 increased as 

infection rates increased from 0 to 20 percent, 

but decreased as infection rate increased from 40 

to 80 percent. At a high initial density and 

relatively low infection rates, Cronartium seems 

to serve as a selective thinning agent thus 

allowing surviving trees to grow better. At 

higher infection rates, reduced growth and 

greater mortality among infected trees caused a 

decrease in the age 20 basal area per acre 

estimate. With an initial density of 400 stems 

per acre, basal area per acre estimates at age 20 

decreased as infection rate increased from 0 to 

80 percent. At this relatively low initial 

density, increased mortality associated with 

higher infection rates apparently did not benefit 

surviving trees. At a density of 400 trees per 

acre the intra-species competition is very likely 

having little effect on growth anyway. Figure 2 

shows the development of the 400 and 800 tree per 

acre stands under different infection rates. At 

an infection level of 50 percent, both the 400 

and 800 tree per acre stands showed about 10 

sq.ft./acre less basal area at age 20 than a 

com~arable stand with no Cronartium infection. 

At infection levels greater than 50 percent the 

loss in basal area at age 20 is greater in the 

800 tree per acre stand. 

BASAL AREA 

(sq.f t./acre) 

--5 .- -- 

REES PER ACRE -.- -. --..__ 

REES PER ACRE -..- -.- -- - *+ - 

INFECTION RATE 

Figure 2. Plot of age 20 basal area per acre vs 

infection rate for stands with densities of 400 and 800 stems per acre at 

age 10. 

SbWRY AND CONCLUSIONS 

Data from 137 plots located in slash pine 

plantations in the coastal plain of Georgia, 

Florida, and South Carolina were used to examine 

the effect of fusiform rust on the basal area 

growth of slash pine. A paired comparison 

t-test on plot averages, analysis of covariance 

tests, and a test on paired trees of the same 

initial size on the same plot provided evidence 

to support the hypothesis that trees infected 

with Cronartium stem cankers grow less than 

comparable uninfected trees. Sluder (1977) and 

Jones (1972) found differences in average sizes of 

uninfected and infected slash pines although some 

differences were not statistically significant. 

Burns and Hu (1985), Powers et al. (1974), and 

Froelich et al. (1983) found significant differences in average tree sizes between severely 

infected trees and uninfected or less severely 

infected trees; 

A growth model was developed to predict the 

basal area growth of infected and uninfected 

trees. Dummy variables were included in the model 

to adjust growth estimates for infected trees, 

Because of the severity of rust infection in 

the South and its impact on growth and mortality 

of slash pine, managers must consider rust infection levels when estimating growth and yield of 

slash pine plantations. Clutter and Devine 

(1982), Nance et al, (1983), Borders and Bailey 

(1985), and others have incorporated rust infection considerations into growth and yield systems. 

Ideally, a growth and yield system which includes 

prediction of percent rust infection and separate 

estimates of growth and mortality for infected and 

uninfected trees should be developed to refine 

growth and yield estimates for slash pine plantations subject to fusiform rust infection. 

LITERATURE CITED 

Alder, Denis. 1979. A distance-independent tree 

model for exotic conifer plantations in east 

Africa. For. Sci. 25:59-71. 

Bailey, R. L., L. V. Pienaar, B. D. Shiver, and 

J. W. Rheney. 1982. Stand structure and 

yield of site-prepared slash pine 

plantations. Univ. of Ga., Athens. 83 p. 

Barber, J. C. 1961. Growth, crown form ,and 

fusiform rust resistance in open-pollinated 

slash pine progenies. Proc. Sixth South. 

Conf. on Forest Tree Improvement. p 97-104. 

Borders, B. E. and R. L. Bailey. 1985. Prediction of percent rust infection in slash 

and loblolly pine plantations, PMRC Res. 

Pap. No. 1985-2. School of Forest Resources, 

Univ. of Ga., Athens. 33 p. 

Burns, P. Y. and S. C. Hu. 1985. Effects of 

fusiform rust on growth of planted slash 

pines. Pages 231-234 in Eugene Shoulders, 

ed. Proc. of Third Biennial South. 

Silvicultural Res, Conf. USDA For. Serv. 

Gen. Tech. Rep. SO-54. 589 p. South. For. 

Exp. Stn., New Orleans, LA. 

Clutter, J. L. and 0. J. Devine. 1982. Joint 

estimation of mortality for infected and 

uninfected trees in slash pine plantations 

subject to fusiform rust infection. PMRC 

Res. Pap. No. 5. School of Forest Resources, 

Univ. of Ga., Athens. 34 p. 

Cochran, W. G. and G. M. Cox. 1950. Experimental 

Design. John Wiley and Sons, New York. 

454 p. 
Cowling, E. B,, R, J, Dinus, and R. A. Schmidt. 

1977. A status report and recomendations 

for research. pages 1-18 in R, A. Schmidt 

and R, J. Dinus, eds, Management of fusiform 

result in southern pi'nes. Symp. Proc. Univ. 

Fla., Gainesville. 163 p. 

Daniels, R. F. 1981. An integrated system of 

stand models for loblolly pine. Ph.D, 

Dissertation, Virginia Polytechnic Institute 

and State University, Blacksburg, VA. 105 p. 

Dell, T. R. and C. H. Driver. 1963. The relationship of dbh to fusiform stem cankering in 

sold field slash pine plantations. J. For. 

61:872. 

Froelich, R. C., W. L. Nance, and G. A. Snow. 

1983. Size and growth of planted slash 

pines infected with fusiform rust. For. 

Sci, 29:527-534. 

Jones, E. P., Jr. 1972. Fusiform rust affects 

slash pine. J. For. 70:350-352. 

Nanee, W. L., R. C. Froelich, T. R. Dell, and E. 

shoulders. 1983. A growth and yield model 

for unthinned slash pine plantations 

infected with fusiform rust. For. Serv. 

Gen. Tech. Rep. SE-24. 8 p. Southeast. 

For. Exp. Stn., Asheville, 

Newberry, J. D. and L. V, Pienaar. 1978. 

Dominant height growth curves for siteprepared slash pine plantations in the lower 

coastal plain of Georgia and Florida. Univ. 

of Ga. Sch. of For. Resources Plantation 

Manage. Res. Coop. Res. Pap. 4, Univ. of 

Ga,, Athens, GA. 47 p. 

Powers, H. R., Jr., J. P. McClure, H. A. Knight, 

and G. F. Dutrow. 1974. Incidence and 

financial impact of fusiform rust in the 

south. J. For, 72:298-401. 

Searle, S. R., F. M, speed, and G. A. Milliken. 

1980. Population marginal means in the 

linear model: an alternative to least 

squares means. The American Statistician 

34:216-221, 

Sluder, E. R. 1977. Fusiform rust in loblolly 

and slash pine plantations on high-hazard 

sites in Georgia. USDA For. Serv. Res. Pap. 

SE-160. 10 p, Southeast. For. Exp. Stn., 

Asheville, NC. 

Zobel, Bruce and Marvin Zoerb. 1977. Fusiform 

rust management strategies in concept: 

reducing fusiform rust in plantations 

through control of the seed source. Pages 

98-109 in R. J. Dinus and R. A Schmidt, eds. 

Management of fusiform rut in southern 

pines. Symp. Proc. Univ. Florida, 

Gainesville. 163 p. 
KANAGENENT AND PEST MANAGmENT CONSIDERATIONS ON DROUGHTY 

SOILS: FOUR YEARS RESULTS' 

David L. ~ulhavy', Kenneth 6. Watterston, James C. Kroll and James R. Meeker 

Abstract.--Four year survival of pines on droughty (Typic 

Quartzips snments) soils was best for longleaf pine and 

Terr-SorbR-treated loblolly pine. Pest considerat ions 

include town ants and Nantucket pine tip moths on loblolly 

pine. Untreated loblolly pine had reduced leader and 

total height growth anfi increased tip moth infestations, 

compared to Terra-Sorb and clay-slurry treated loblolly 

pine. Soil texture averaged less than eight percent silt 

and clay combined in the treatment areas. 

INTRODUCTION METHODS AND MATERIALS 

Intensive site preparation and planting with 

genetically improved seedlings are widely used 

methods for southern pine regeneration. On 

droughty sites, clearcutting followed by these 

methods may lead to less than optimum results. 

While attempting to regenerate pines on droughty 

soils (= Tonkawa series), management and pest 

management options should be considered. Tonkawa 

soils, a Typic Quartzipsamment, consisting of 

excessively drained sandy soils on uplands, are 

characterized by low fertility with slopes ranging 

from 0-20 percent. In east Texas, these soils 

cover approximately 23,000 acres in Nacogdoches, 

Panola, Rusk and San Augustine Counties. Site 

index is approximately 55 (base 50 years). 

Original forest cover was probably dominated by 

shortleaf pine (Pinus echinata) with longleaf pine (z. palustris) intermixed. Dominant hardwood 

species were sand j ack (blue j ack) oak (Quercus 

incana) . 

In clearcut areas, with or without chopping, 

burning and/or shearing and windrowing and 

whole-tree chipping, regeneration is difficult due 

to the removal of organic matter and exposure of 

bare mineral soil to the sun and wind. This 

greatly decreases the moisture holding capacity of 

the soil as well as increasing surface 

temperature. Attempts to reforest these areas to 

pines often result in less than 10 percent 

survival. In 1983, a study was initiated to 

investigate management and pest management 

considerations, on these droughty soils. Kroll et - al. (1985) reported the first two year's 

survival. This paper reports on four year results 

and additional management considerations. 

1 

Paper presented at Southern Silviculture 

Research Conference, Atlanta, Georgia, Kovember 

4-6, 1986. 

2 

Respectively, Associate Professor of Forest 

Entomology and Pest Management, Professor of 

Forest Soils, Professor of Forest Wildlife 

Management and Graduate Research Assistant, Center 

for Applied Studies, School of Forestry, Stephen 

F. Austin State University, Nacogdoches, TX 75962 

Study plots were established on Tonkawa (Typic 

Quartzipsamment) soils (Dolezel 1980) 6 miles 

West of Garrison, TX. Seven treatments with 

eight replicates were established. Within each 

replicate, 48 seedlings were planted on an 8x8 

foot spacing in four rows of 12 seedlings each. 

A buffer zone equal in size to the replicates 

was planted between and an the ends of each 

replicate with bare rooted loblolly pine 

seedlings. The seven treatments, randomly 

assigned in each replicate, were: 

1. bare-rootefi foblolly pine, 

2. Terra-Sorb treated loblolly pine, 

3. clay-slurry treated loblolly pine, 

4, bare-rootefi slash pine, 

5. Terra-Sorb treated slash pine, 

6. clay-slurry treated loblolly pine, and 

7. containerized longleaf. 

Details of plot lay-out are presented in Kroll 

-- et al. (1985). 

~erra-sorbR is a starch-based synthetic 3 acrylic polymer capable of absorbing water . It 

forms a hygroscopic substance used as a root dip 

to increase moisture holding capacity. 

Clay-slurry is a similiar but inorganic compound 

also forming a hygroscopic substance when mixed 

with water. Replicates were hand-planted using 

standard methods in January 1983. The study was 

replicated in January 1984 and 1985 but failed 

due to excessively low winter temperatures, high 

rabbit predation, and drought and drying winds 

in 1984 and 1985, respectively. 

Survival counts were taken at the end of the 

four growing seasons and data grouped to compare 

survival, differences in height growth, 1986 

leader length and Nantucket pine tip moth, 

Rhyacionia frustrana, infestation rates. All 

data were analysed used one-way analysis of 

variance and means compared using ~uncan's 

multiple range test at P = 0.05. 

3 

Industrial Services International, Inc., 

Bradenton, FL 38282. 
RESULTS AND DISCUSSION 

Four-year survival is reported in Table I. 

Note the steep decline in survival in the 

1983-1984 growing seasons and the absence o! 

significant mortality in the 1985-1986 growing 

seasons. At the end of the 1986 growing season, 

longleaf pine had 56 percent survival followed by 

40.1 percent survival for Terra-Sorb -treated 

loblolly pine (11. taeda). Slash pine, P, 

palustris, had an average survival of 13 percent 

for all three treatments, combined. 

Table I. Survival of loblolly, slash and 

longleaf pine, Typic Quartzipsamments soils, four 

year results. 

Treatment October 

1983 1984 1985 1986 

Longleaf Pine 85.2 56.5 56.0 56.0 

Loblolly R81. 3 50.8 46.5 40.1 

(Terra-Sorb ) 

Lob lo 1 ly 49.2 31.9 31.3 29.2 

(Clay Slurry) 

Loblolly 50.5 19.6 21.3 21.3 

(Untreated) 

Slash R4 6.9 20.8 i6.2 14.5 

(Terra-Sorb ) 

Slash 35.4 16.9 12.0 10.4 

(Clay Slurry) 

Slash 41.4 16.9 23.5 14.1 

(Untreated) 

The decline in loblolly pine survival from 1984 

to 1986 was due primarily to Texas leaf-cutting 

ants (town ants), Atta texana. Town ant predation 

is common on sandy sites (Moser 1984) and damage 

to pines is most severe in winter when there is 

little or no other green vegetation for the ants 

to forage (Thatcher et al. 1986). Currently, the 

Dowfume MC-2 formulation of methyl bromide, used 

for town ant control, and produced by Dow Chemical 

Company, is no longer available. The Texas Forest 

Service is involved with developing alternatives 

to methyl bromide for the control of town ants (R. 

Scott Cameron, Texas Forest Service, Lufkin, TX, 

pers. commun.). 

Additional pests of loblolly pine on the study 

plots include the redheaded pine sawfly, 

Neodiprion lecontei, and the Nantucket pine tip 

moth (NPTM). Sawflies defoliated portions of the 

crown of loblolly pine. NPTM infestation rates 

were significantly higher on contra1 loblolly pine 

than those treated with Terra-Sorb (Table 2). 

These higher infestation rates led to increased 

multiple leaders and crooked boles in the control 

plots. Due to economic contraints, control of 

NPTM may not be practical on these sites. 

Long-term effects of tip moth are difficult to 

assess, but include bole sweep and compression 

wood (Hedden and Nebeker 1984). Cade (1985) 

indicated tip moth damage is greater and lasts 

longer on poorly stocked or open grown stands. 

Table 2. Nantucket pine tip moth infestation 

rates for four-year old loblolly pine, Typic 

Quartzipsaments soils. 

Treatment Number of Infestation R te 

trees (mean + SD) T 

Untreated 32 7.8% + 7.8a 

Clay Slurry 5 6 5.8% + 4.5ab 

Terra-Sorb R 7 7 5.1% + 5.9b 

All Trees Combined 165 5.9% 

Means followed by same letter not 

significantly different at Px.05 using Duncan's 

Multiple Range Test. 

For loblolly pine, fourth-year leader length 

and total tree height were significantly greater R for Terra-Sorb and clay-slurry treated trees 

compared to control trees (Tables 3 and 4). 

During the 1986 growing season, 43 percent of 

the total height growth occurred for loblolly 

pine, compared over all treatments. Average 

height ranged from 148 cm for unkreated loblolly 

to 181 and 190 cm for Terra-Sorb and 

clay-slurry treated loblolly pine, respectively 

(Table 4). 

Table 3. Fourth year leader length and percent 

total height, four year old loblolly pine, Typic 

Quartzipsamments soils. 

Treatment Number Leader Lengih Percent Total 

of trees (cm)x + SD Height 

Untreated 32 60 2 28 A 40.5% 

Clay Sturry 56 91 + 24 B 47.9% 

~erra-sorbR 77 85 + 33 C 47.0% 

- 

165 82 + 31 43.1% 

'Pfeans followed by same letter not significantly 

different at P1.05 using Duncan's multiple range 

test. 
Table 4. Total tree height for four-year old 

loblolly pine, Typic Quartzipsamments soils. 

Trea tment Number of Height (cm) 

trees (mean + SD) 

Untreated 32 148 + 56a 

Clay Slurry 56 190 f 51b 

Terra-Sorb R 7 7 181 2 57b 

A11 Trees Combined 165 178 2 56 

' Means followed by same letter not significantly 

different at p =.05 using Duncan's Multiple Range 

Test. 

Soil texture (Table 5) reflected the deep sand 

conditions (Dolezel 1980). Percent silt and clay 

combined, averaged less than eight percent for 

the top six centimeters measured over three 

sites. Longleaf pine, with 56 percent survival, was emerging from the grass stage. No brown 

spot needle blight, caused by Scirrhia acicola, 

was detected. Hazard rating for brown spot in 

this site is low as less than 50 percent of the 

stand is infected (Anderson et al. 1984). 

On these droughty sites, stand disturbance 

during harvest cutting should be kept to a minimum. Containerized longleaf and Terra-Sorb R 

-treated loblolly pine-had better survival 

(Table I), but pest considerations (town ants 

and tip moths) reduce the usefulness of loblolly 

pine. To regenerate these sites, minimum 

exposure to drying winds to conserve soil 

moisture and to reduce decomposition of humus 

and organic remains (Wilde 1948, 1958) is 

recommended. 

Table 5. Texture analyses of planting sites TN-I (planted Jan. 83), TN-2 (planted Jan. 85, and an undisturbed natural stand (TN-3), a Typic Quartzipsamment. 

TN-1 TN-2 TN-3 

Sampling % % % % % % % % % 

Depth (cm) sand silt clay sand silt clay sand silt clay 

0 - 6 92.0 4.5 3.5 91 .O 4.7 4.3 92.1 5.1 2.8 

30 - 38 94.1 3.6 2.3 91.8 3.9 4.3 92.5 4.4 3.1 

61 - 69 95 .O 3.2 1.8 92.5 3.8 4.2 92.6 4.4 3.0 

91 - 99 96.0 2.6 1.4 92.6 3.6 4.7 92.5 4.6 2.9 

122 - 130 96.1 2.6 1.3 92.5 3.8 4.4 92.7 4.4 2.9 

152 - 160 96.2 2.7 1.1 92.7 3.8 4.4 93.4 4.3 2.3 

Average 94.9 3.2 1.9 91.7 3.9 4.4 92.7 4.5 2.8 

LITERATURE CITED Doelzel, Raymond. 1980. Soil survey of 

Nacogdoches County, Texas. U.S. Dept. Agr. 

Anderson, R.L., R.A. Schmidt and G.A. Snow. 1984. Soil Conservation Serv. and Forest Service. 

Integrated pest management in regeneration-- 146 p. plus 53 plates. 

early growth phase of pine stands--diseases, pp. 

54-71, S.J. Branham and G.D. Hertel, eds. Hedden, R.L. and T.E. Nebeker. 1984. Integrated 

Integrated Forest Pest Management Symposium: The pest management in pine stands (0 to 50 

Proceedings, Athens, GA, June 19-21, 1984, yrs.)-- insects, pp. 39-53, 5.3. Barnham and 

Univ. Georgia, Cen. Continuing Ed., Athens, Ga. G.D. Hertel, eds. 9. G. 

281p. 

Kroll, J.C., W.C. Deauman, C.D. Foster, D.L. 

Cade, S.C. 1985. Pest management of pine Kulhavy and D. Tracey. 1985. Survival of 

reproduction weevils and tip moth. Clemson pines on droughty soils: Two year results, 

University Fifth Annual Forestry Forum. pp. 128-131, E. Shoulders, ed. Proc. Third 

Integrated Pest Management: The Decision-Making Biennial Southern Silviculture Research Conf. 

Approach. Clemson, South Carolina. U.S. Dept. For. Serv., So. For. Exp. Sta., 

Gen. Tech. Rep. 50-54. 589p. 
Moser, John C. 1984. Town ant. In: History, 

status, and future needs for entomology 

research in southern forests, pp. 47-52, T.L. 

Payne, R.F. Billings, R.B. Coulson and D.L. 

Kulhavy, eds, Proc, 10th Anniversary East 

Texas Forest Entomology Seminar, 1983. Tex. 

Agr. Exp. Sta. MP 1553. 72 p. Agr. 

Thatcher, R.C., G.N. Mason and G.D. Hertel. 

1986. Integrated pest management in southern 

pine forests. U.S. Dept. Agr. Forest Service 

and Coop. State Res. Serv. Agr. Handbk. 650. 

38 p. 

Wilde, S.A. 1948. Forest soils and forest 

growth. Chronica Botanica, Waltham, Mass. 

Wilde, S.A. 1958. Forest soils. Ronald Press 

Co., New York, NY. 537 p. 
Vegetative Management 

Moderator: 

Dean H. Gjerstad 

Auburn University 

RELATIONSHIPS AMONG FIRST-YEAR LOBLOLLY PINE SEEDLING PERFORMAKCE, VEGETATIOK REGROWTH, 

EKVIROKMENTAL CONDITIONS AHD PLANTATION PUNAGEMENT PRACTICES1 

Sarah M. Nusser and Thomas R. Wentworth 2 

Abstract.--Performance of loblolly pine (Pinus taeda L.) seedlings, regrowth of natural 

vegetation and environmental conditions were monitored during the first growing season of an 

experimental plantation established on a recently clearcut site in the Piedmont Qf North 

Carolina. High and low intensities of both site preparation (shearing, piling and doubledisking versus chopping) and cultural practice (herbicide versus no herbicide) were applied 

in a factorial to create four treatment combinations. Chopping left significantly more leaf 

and wood litter on the soil surface than did shear-pile-disk; both radiant energy at the 

litter surface and maximum soil temperature were higher in shear-pile-disk. Chopping favored 

the regeneration of vines and trees from intact root systems and the establishment of grasses, whereas the shear-pile-disk treatment resulted in a community derived from seed and 

composed largely of early successional forbs. Although site preparation had no significant 

effect on pine growth in the first year, an observed trend toward better performance in 

shear-pile-disk relative to chopping was confirmed in the following year. Herbicide application had modest effects on the regrowth of natural vegetation. However, this treatment 

increased the radiant energy and, in shear-pile-disk, increased the availability of nitrate. 

Height growth of pines was slower and diameter growth more rapid in plots treated with 

herbicide. Height growth of pines was positively correlated with soil ammonium concentration, and negatively correlated with the cover of wood and leaf litter and with the volume of 

vines and canopy trees, factors which could have contributed to a reduction in ammonium 

pools. Diameter growth of pines was positively correlated with reduced regrowth of natural 

vegetation and greater nitrogen availability. 

Keywords; Competition, site preparation, herbicide, Finus taeda L. 

INTRODUCTION 

Several studies have established that 

vegetation regrowth on recently clearcut sites 

reduces nutrient losses caused by increased 

leaching and erosion, increased decomposition, and 

decreased plant uptake (Bormann and Likens 1979; 

Boring and others 1981; Cox and Van Lear 1985). 

Vegetation regrowth, however, may also interfere 

with performance of pine seedlings in plantations. 

A number of investigators have demonstrated that 

pine growth can be significantly increased by 

reducing hardwood competition (Freeman and Van 

Lear 1977; Sterrett and Adams 1977; Clason 1978; 

Cain and Mann 1980; Carter and others 1984). 

Herbaceous plants have also been implicated as 

competitors of pine seedlings in areas supporting 

a small proportion of woody regrowth (Schultz 

1976; Nelson and others 1981; Carter and others 

1984). 

'paper presented at Southern S ilvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986, Paper No. 10797 of. the Journal Series 

of North Carolina Agricultural Research Service, 

Raleigh, NC 27695-7601. 

'~raduate Student, Department of Statistics, 

Iowa State University, Ames, IA 50011; and Associate Professor of Botany, North Carolina State 

University, Raleigh, NC 27695-7612. 

The effect of various site preparation 

methods on the pine-vegetation interaction is 

poorly understood. Schultz (1976) indicated 

that intensive site preparation in Florida 

flatwoods could improve first-year tree survival by reducing vegetative competition for 

light, water, and nutrients. Haines and 

Pritchett (1965), however, suggested that the 

effect of intensive site preparation on nutrient availability in these lowland areas 

could be more important than vegetation regrowth in determining pine growth. 

The paucity of investigations which quantify 

both the abiotic environment and vegetation regrowth in relation to early pine performance 

under various forest management practices provided motivation for the research described in 

this paper. Our objective was to study, in a 

nondestructive and quantitative fashion, the 

performance of loblolly pine (Pinus taeda L.) 

seedlings in relation to their immediate environment under the influence of high and low 

intensity site preparation and cultural treatments in the North Carolina Piedmont. To 

better understand how forest management affected the pine-vegetation interaction, we took a 

two-fold approach of: (1) assessing the effects 

of the treatments on vegetation regrowth, the 

abiotic environment, and pine growth; and (2) 

determining which growth forms and environmental factors were most closely associated with 

pine growth. This paper examines the first 

year's results of the study. 
METHODS Assessment of Environmental Conditions 

Study Site and Experimental Design 

The study was established following clearfelling in February 1981 of a 22-year-old second 

rotation loblolly pine stand as part of the Site 

Productivity Study being conducted by the North 

Carolina State University Southern Forest Research 

Center. The stand was located on land owned by 

Champion International Corporation in the northeastern North Carolina Piedmont (Vance County) on 

soils which belong to the Cecil series (clayey, 

kaolinitic, thermic, Typic Hapludult). 

The experiment involved four treatments derived 

from a factorial of two site preparation intensities and two levels of herbicide treatment. The 

low intensity site preparation consisted of one 

pass of a heavy drum chopper (treatment referred 

to hereafter as CH). In the high intensity site 

preparation, stems which remained on the site 

after harvest were sheared at ground level, organic debris was piled into windows, 

was subsequently disked (DI). Velpa@ gridballs the site 

(hexazinone) were applied at a rate of 10 kg/ha 

for the high intensity herbicide treatment (H+). 

No herbicide was applied in the low intensity 

herbicide treatment (H-). The four treatment 

combinations (CHH-, CHH+, DIH-, DIH+) were arranged in a split-plot design within each of three 

blocks; site preparation treatments were assigned 

to whole-plots and herbicide treatments were 

assigned to split-plots. A 15 x 30 m measurement 

plot was established within each of the 12 blocktreatment areas. 

Site preparation was carried out in July 1981. 

The site was hand planted with improved nursery 

stock of one year old loblolly pine seedlings on a 

2x3 m spacing in March 1982. Herbicide was 

applied in May 1982. 

Assessment of Vegetation Regrowth 

Four pine seedlings were randomly selected 

within each measurement plot. For each pine, a 

3 x'2 m subplot was positioned such that the pine 

seedling was located at the center of the plot. 

In August 1982, vegetation regrowth surrounding 

the pines was assessed by recording the species, 

approximate outline shape (i.e., common geometric 

solids such as cone, ellipsoid, etc.) and appropriate outline dimensions for each plant or plant 

part located within 1 m of the central pine. 

Plant dimensions were used to calculate the aboveground space occupied by each individual, hereafter referred to as volume. All species were 

classified as belonging to one of seven growthforms: forb, grass, sedgelrush, vine, shrub, 

understory tree, canopy tree. Growth form classes 

w$re chosen to reflect differing ecological behaviors of species within a community. For example, 

understory trees can be distinguished from canopy 

trees by their slower growth rates and greater 

shade tolerance. 

Integrating light neters, constructed fron 

booklets of photosensitive diazo paper (Francis 

1970), were used to obtain an estimate of the 

amount of radiant energy reaching the forest 

floor of each subplot, relative to that which 

reached an area within the study site lacking 

vegetation and slash. Four light meters per 

subplot were set out before dawn on a mostly 

sunny day in August, and retrieved at dusk. 

Maximum-minirourn thermometers were inserted in 

the soil to a depth of 15 ctn at the edge of 

each subplot in late July, and were monitored 

for maximum and minimum temperatures every two 

weeks thereafter. Percentage cover for both 

wood and leaf litter located within 1 m of the 

pine were visually estimated in each subplot 

during May 1982. Information on percentage 

soil moisture, and soil ammonium and nitrate 

concentrations for each measurement plot were 

provided by P.M. Vitousek (personal communication). Soil samples for these measurements 

were taken to a depth of 15 cm in June, July, 

and August 1982. Percentage soil moisture was 

determined gravimetrically; ammonium and nitrate concentrations were assessed via KC1 

extraction and colorimetric determination on an 

autoanalyzer. 

Assessment of Loblolly Pine Growth 

The height and root collar dianeter of the 

central pine within each of the 48 subplots 

were measured in May and October 1982 to determine the rate of growth for each pine during 

the growing season. 

Calculations and Analyses 

The volumes for all individual plants within 

a growth form class were summed to obtain a 

growth form volume per ground area for each 

subplot. For each growth form class, growth 

form volume was also expressed as a percentage 

of total subplot volume. Averages over subplots within measurement plots were used in the 

analyses. 

Means over the growing season were calculated 

for all soil variables, since treatment responses were parallel over the time span indicated. 

Both maximum and minimum temperatures were 

averaged over a two month period (late July to 

late September), while soil moisture, and ammonium and nitrate concentrations, were averaged 

over the three month period extending from June 

through August. 
Relative growth rates were used as pine height 

and diameter growth variables to reduce the influence of initial size on the analyses. These relative growth rates were calculated for each pine 

using the following equation (Evans 1972): 

relative growth rate = 

ln(0ctober measurement) - ln(initia1 measurement) 

(time 2 - time 1) 

where (time 2 - time 1) represented the entire 

growing season and was considered equivalent to 1. 

Treatment effects on vegetation regrowth, environmental conditions, and loblolly pine growth 

were tested using ANOVAs and Fishers's protected 

lsd tests, Correlation coefficients among August 

vegetation volumes, environmental parameters, and 

pine relative growth rates were used to detect 

possible relationships. 

A principal components analysis biplot (Gabriel 

1971), using August growth-form volumes as attributes of the measurement plots, was employed to 

further investigate the relationships between 

treatments and vegetation regrowth. In prinicpal 

components analysis the original data space, in 

this case measurement plot points located within 

the seven dimensional space defined by the growthform volume axes, is redefined irrespective of the 

original axes such that the first new axis (called 

a component) accounts for the maximum amount of 

variation present in the measurement plot points. 

Subsequent components are sequentially determined 

such that each accounts for the maximum amount of 

the remaining variation and is orthogonal to the 

previous components. Each component is a linear 

combination of the original axes, and the first 

two or three components can be used to summarize a 

large proportion of the variation in the data. 

The biplot aspect of this analysis refers to a 

representation of the original axes (growth-form 

vectors in Figure 1) as projected onto the two 

dimensional space defined by two components. The 

degree to which a given component is correlated 

with one of the original axes can be determined 

from the relative length of the growth-form vector's projection onto that component. 

For example, in Figure 1, the first component 

is positively correlated with forbs and negatively 

correlated with grasses, but has little association with understory trees. Likewise, measurement 

plots which have a high positive score on the 

first component have relatively large volumes of 

forbs and relatively small volumes of grasses. 

All statistical analyses, excepting the biplot, 

were performed using Statistical Analysis System 

procedures (SAS Institute, Inc. 1982). Results 

reported were significant at p<=.05 unless otherwise indicated. Since vegetation regrowth was 

quite variable, p-values less than .l0 were reported for some of these results and should be interpreted as indicative of potential trends. 

RESULTS 

Effects of Treatments on Vegetation Regrowth 

Significantly larger volumes of grasses 

(e.g., Panicum spp.) and canopy trees (e.nl. -. Quercus spp., Liriodendron tulipif era L, Acer 

rubrum L) were present in CH sites than in DI 

sites (Tables 1 and 2). Canopy trees also made 

up a larger proportion of the total vegetation 

volume in CH relative to DI plots, whereas 

forbs contributed significantly more to total 

vegetation volume in DI sites. Most of the 

forbs (e.g., Aster spp., Erigeron spp., 

Verbascum thapsus L.) were early successional 

species; few herbaceous species present in the 

adjacent forest were found in subplots. 

Vines (e.g., Lonicera spp., Parthenocissus 

quinquef olia L., Vitis spp.) contributed more 

toward total vegetation volume in the H- plots 

(p=.06), while canopy trees performed better 

(in terms of both absolute volume and percentage of total volume (p=.07)) in the H+ plots. 

The greater volume of canopy trees in H+ and, 

in particular, CHH+ plots was unexpected and 

apparently existed prior to herbicide application. An ANOVA on May 1982 canopy tree volumes 

(unpublished data) collected prior to herbicide 

damage suggested these pretreatment differences, and an analysis of canopy tree relative 

growth rates revealed no significant main effects or interactions involving cultural treatments, 

There was an interaction between site preparation and herbicide treatment for volume of 

vines (pe.06) expressed as a percentage of 

total vegetation volume. The proportion of 

vine volume was greater in CHH- than in CHH+ 

plots, and both CH treatments had greater vine 

volume relative to total vegetation than did DI 

treatments. A similar interaction was observed 

for absolute volume of canopy trees; the volume 

was greater in CHH+ than in CHH- plots, and 

both CH treatments had greater canopy tree 

volume than did DI treatments. 

The first two axes of the biplot accounted for 

60.4 percent of the variation in the data, with 

36.4 percent and 24.0 percent accounted for by 

components 1 and 2, respectively. The biplot 

showed a clear separation between CH and DI 

plots along the first axis (Figure 1). Growthform vectors indicated that CH plots were consistently associated with greater grass, canopy 

tree, and, to a lesser extent, sedge volumes. 

DI plots were consistently associated with 

greater volume of forbs. There was considerable within-treatment compositional variation 

for site preparation treatments, particularly 

for the CH treatment. 
\ SHRUBS 

FIRST COMPONENT 

FICUid :. Locations of 12 r&ieasurer.]ent plots relative to the first 2 components of a 

principal components analysis using growth-form volumes as plot attributes. Outlines 

indicate membership of plot6 in Slocks (solid lines) and site preparation treatnents 

(dashed lines); cultural treatnents are indicated by the notations :!+ (herbicide) and H- 

(no herbicide). See text for interpretation of plot. 
T . Signifimt treatmat effects on grawth form, emir-nt , arid pine grawth variable^.^ 

kpendent 

Variable 

Site Cultural Site Preparation 

Preparation x Qlltural 

Forbs (percent total voltme) DI > CH (*) 

Grasses (absolute volume) CN > DI (*) 

Vines (percent total volume) 

Canopy trees (absolute voltsnit?) CN > DI (*) 

(percent total volme) CH > DI (*) 

H- > H+ (p.06) Q3-i- > CHH+ > DM- = DIH+ (p.06) 

H+ > H- (*) cHH+ > (3M- > Dm- = DM+ (*) 

H+ > H- (p.07) 

Light DI > CH (*) H+ > H- (*) 

Wood litter CH > DI (*) 

M litter cr-1 > DI (*) 

Maxhm soil temperature DI > CH (*) 

Soil nitrate concentration DIH+ > DM- = CHH- = CHH+ (*) 

Pine height growth rate 

Pine diamter grawth rate 

?l'reatment differences assessed by Fisher's protected lsd test. 

Significance levels: * = p 5 .05, ** = p 2 .01, *** = p 2 .001. 

%reatment symbols : DI = disk, M = chop, H+ = herbicide, H- = no herbicide, (HI+ = chop-no herbicide, 

cHH+ = chopherbicide, DIH- = diskno herbicide, Dm = disk-herbicide. 

TABLE 2. Absolute vegetation volume arid percentage of total vegetation by treatment combination for seven graJtMorm 

(means over blocks 2 standard errors, N=3). 

m- m+ DIH- DIH+ 

Absoluteb percentC Absolute Percent Absolute Percent Absolute Percent 

Forbs 

41.0 2 8.2 15.7 2 4.9 39.4 2 12.5 14.6 2 5.9 96.3 2 68.3 48.9 2 9.4 55.8 2 41.5 48.3 2 18.7 

Grasses 

43.3213.0 15.52 4.3 40.5214.1 13.924.5 13.22 7-7 16.1+8.1 7.92 4.3 13-12 7.2 

Sedges and rushes 

0.520.2 0.2+0.1 1.120.5 0.420.2 0.420o1 0.420.2 0*420*3 0*6+0*6 

Vines 

21.82 8.0 9.1 2 4.5 14.7 2 11.6 5-92 4.8 2-42 2.3 0.72 0.6 0.62 0.3 0.72 0.4 

Shrubs 

45.8 2 39.9 13.4 2 11.1 28.9 2 21.9 9.2 2 6.8 51.6 2 42.2 20.6 2 7.6 12.3 2 2.8 23.6 2 13.8 

Understory trees 

5.62 5.6 2.72 2.7 0.72 0.3 0.220.1 0.02 0.0 0.020.0 1.82 1,8 le12 1.1 

Canopy trees 

124.1528.2 43.52 7.2 162.5222.8 55.924.1 11-22 8.7 13.228.2 7.1 2 4*6 12+6+ 7.3 

Total Vegetation 

282.0 + 42.5 

9reatment symbols as in Table 1. 

%egetation vole (10 cm3/m2 ground area). 

'percentage of total vegetation vole. 
Block separation was evident in the biplot DISCUSSION 

(Figure I), primarily on the second component. 

Greater volumes of forbs, vines, and understory 

trees were present in block A than in other 

blocks, whereas block B tended to have greater 

grass, canopy tree, and sedge volumes. Block C's 

position in the biplot reflected a greater volume 

of shrubs, but was to some extent intermediate to 

the positions of blocks A and B. 

Herbicide treatments appeared to be compositionally similar since the H+ and H- treatments 

for each block-site preparation combination were 

relatively close to one another. This similarity 

was particularly evident in the DI site preparation treatment. Overall, the effects of site 

preparation and blocking on composition were more 

pronounced than those of herbicide treatment. 

Effects of Treatments onEnvironmenta1 Conditions 

Site preparation had a significant effect on 

the amount of litter left on the sites, with cover 

of both leaf and wood litter in CH plots higher 

than that found in DI plots (Tables 1 and 3). 

Maximum soil temperatures and the amount of light 

energy reaching the forest floor were greater in 

DI than in CH sites. H+ plots also received 

greater radiant energy relative to H- plots. 

There was a significant interaction between site 

preparation and herbicide treatment for soil nitrate concentrations, with concentrations higher 

in DIH+ plots than in plots receiving all other 

treatments. 

Effects of Treatments on Loblolly Pine Relative 

Growth Rates 

Herbicide treatments had a significant effect 

on both height and root collar diameter growth 

rates (Tables 1 and 4). Diameter growth rates 

were significantly higher in H+ plots, whereas 

height growth rates were higher in H- plots. Site 

preparation did not significantly affect either 

height or diameter growth. 

Associations Between Vegetation Regrowth, 

Environmental Conditions, and Loblolly Pine 

Relative Growth Rates 

Height growth was negatively correlated with 

August vine and canopy tree volume and both leaf 

and wood litter, and positively correlated with 

soil ammonium concentration (Table 5). Root 

collar diameter was negatively correlated with 

vine volume and wood litter, and positively correlated with light, maximum soil temperature, and 

both soil ammonium and nitrate concentrations. 

Pine height and root collar diameter growth were 

not significantly correlated with one another. 

Significant correlations occurred frequently both 

among environmental variables and between vegetation and environmental variables (Table 5). 

Effects of Treatments on Vegetation Regrowth 

The separation of CH and DI sites along the 

first principal component (Figure 1) suggested 

that site preparation was the most important 

factor influencing composition of vegetation in 

this experiment. Chopping caused minimal damage to stumps and roots, and favored regeneration of growth forms (such as trees and vines) 

which were capable of sprouting rapidly and 

taking advantage of large root system reserves 

plus the enhanced availability of light and 

below-ground resources following harvest 

(Thomas 1980; Borman and Likens 1979; Vitousek 

and Matson 1984). In DI plots, where sprouting 

was restricted by damage to and removal of most 

root systems during site preparation, seed 

regeneration was favored. The high light intensities and increased temperature fluctuations required for germination of most early 

successional forbs (Grime and Jarvis 1975; 

Grime 1979) and the scarcity of individuals 

from the more vigorous growth forms probably 

aided in the establishment of these poor competitors. 

The dichotomy of sprouting versus seed regeneration between site preparation techniques 

was not complete. Factors such as stratification of the seedbank and physiological limitations also may have influenced the composition 

of vegetation regrowth. For example, in Fall 

1981 the recently prepared CH sites supported a 

dense seed-borne population of fireweed 

(Erechtites hieracifolia L), which did not 

appear in the more deeply scraped DI areas 

until the following year as progeny from the CH 

populations. Another exception was seen with 

grasses. Germination of grasses was plentiful 

in both CH and DI plots, but DI individuals 

rarely achieved the size of those in CH plots. 

This differential growth could have resulted 

from the limitations placed upon the net photosynthesis of these predominantly C3 species 

by photorespiration in the high light and high 

temperature environment of the DI plots (Smith 

and Brown 1973, Ehleringer 1978). 

The second axis of the biplot revealed the importance of site specific factors in vegetation 

regrowth (Figure 1). For example, more vigorous regrowth was observed in block A-DI plots 

and was most likely enhanced by the higher 

initial fertility of block A relative to blocks 

B and C (L.A. Morris, P.M. Vitousek, unpublished data), and the moister conditions resulting 

from its low topographic position (mean percent 

soil moisture and standard errors for DI plots 

within blocks A, B, and C, respectively: 

27.7 f 1.2, 16.9 5 2.0, 20.4 2 1.3). The 

larger buried seed pools which have been observed in more fertile sites (Hill 1979) also may 

have contributed to the sharp contrast in CI 

regrowth across blocks. 
sd errors, N-3) for ehromatal variables by trc3atnent coolbination. 

Wbod Litter 11.4 2 1.4 10.3 f 1.6 2.3 + 0.7 2.9 + 0.3 

(percent cover) 

Leaf Litter 93.0 + 1.8 96.82 0.6 

(percent cover) 

bfaxhm temperature 27.9 + 0.1 28.0 + 0.2 29.6 + 0.4 30.4 + 0.1 

(OC> 

I4.m temperature 20.7 + 0.1 20.5 + 0.2 20.7 + 0.3 20.3 + 0.3 

(OC > 

Soil Moisture 23.02 1.1 22.0 + 1.5 22.6 + 3.4 20.8 2 3.5 

(percent dry wight 1 

Soil kmmium 3.3): 0.4 3.3 f 0.3 4.1 f 0.8 

(PP~) 

Soil Nitrate 0.0 2 G.0 0.0 2 0.0 3.9 f 2.4 

(PP~] 

a Treatment symbols as in Table 1. 

Radiant energy measured by a diazo paper light meter, expressed as a percentage of that measured by an unshaded 

control. 

TABLE 4. Means over blocks ( f standard errors, N=3) for loblolly pine relative growth rates in the 1982 growing season 

by treatment combination. 

Treamt ~unbinations~ 

CHI-E- QM+ DIH- DI! :+ 

Sight 1.04 f 0.13 0.75 + 0.09 

Root Collar Diameter 0.26 + 0.06 0.38 + 0.11 0.37 2 0.05 0.65 + 0.03 

a Treatment symbols as in Table 1. 
5. Correlation coefficients bemen loblolly pine relative growth rates, vegetation vo 

tiw .a 

'.Jj.ws Y Total 

Trees Vegetation 

&\%rom~ t 

Light Leaf i"laxd %il 

r Litter Ternperattire um flitrate 

Root Collar diarreter 

-.6C(*) -.42 -.51 

Light 

-.63(*) -.54 -. 7 1 (iw) 

Wood Litter 

.77(iwo .Go(*) .47 

Leaf Litter 

.6G(*) .92(9**) .62(:k) 

FdxW Soil Taperatwe 

-. 58(*) -. 85(;b**) -. 82 (* ) 

Soil Amnium 

-. 45 -. 55 -. 43 
Herbicide application had only moderate inf luence on vegetation regrowth during 1982. Field 

observations evealed local damage (apparently 

where Velpa@ gridballs were placed), but total 

reduction in vegetation was small and limited 

primarily to vines (Table 2). riin may have been 

particularly susceptible to Yelpafldamage because 

their creeping habit would have increased the probability of encountering soil contaminated with 

the systemic herbicide* 

Effects of Treatments on Environmental Conditions 

Site preparation effects on environmental conditions observed in this study were consistent 

with those of other investigations (Haines and 

others 1935; Schultz 1976). The large quantities 

of organic matter which were removed under the 

high intensity site preparation treatment left 

little wood or leaf litter on the soil surface. 

The increased light energy reaching the soil surface in DI sites was a direct result of the sparser foliage. The increased light energy coupled 

with reduced insulation by surface litter probably 

led to higher maximuln soil temperature in DI than 

in CH plots. 

Herbicide application produced little effect on 

most environmental c ditions, probably because of 

the failure of VelpaD to significantly alter 

vegetation regrowth in 1982. The increased light 

energy in H+ plots, however, was most likely a 

result of the slight reduction which did occur in 

most growth-form classes as a result of herbicide 

damage. 

The elevated concentrations of nitrate in DIN+ 

plots relative to all other treatments was found 

to be largely a product of reduced immobilization 

(via microbial uptake) caused by the removal of 

organic residues (Vi tousek and Matson 1984). 

Loblolly Pine Growth in Relation to Vegetation 

Regrowth, Environ~~~ental Conditions and 

Forest Management 

Research on competitive interactions points to 

th'e importance of rapid early growth in the attainment of dominance within a community (Ross and 

Harper 19772; Harper 1973). Enhanced growth may be 

facilitated by an increase in the availability of 

resources and/or a seduction in harmful competitors. Among the resources monitored in this 

investigation, greater pine growth rates appeared 

to be associated with increased ammonium concentrations. Factors which can adversely affect 

nitrogen availability, such as increased quantities of wood and leaf litter, were negatively 

associated with improved pine performance. In 

experiments conducted at the same site, Vitousek 

and Matson (1 984 and personal commrmication) found 

that immobilization of nitrogen in organic matter 

was primarily responsible for reduced ammonium 

(and hence nitrate) availability. Since the 

plantation was probably nitrogen-limited prior to 

harvest (Allen and Ballard 19831, it is possible 

that incorporation of nitrogen into microbial 

biomass may have limited pine seedling growth. 

The positive correlation between root collar 

diameter growth rates and radiant energy may 

have occurred via several pathways. The increase in solar energy associated with a decline in vegetation volume may actually have 

encouraged diameter growth (root collar diameter and crown relative growth rates: r=.76, 

unpublished data); in the absence of direct 

shading by neighboring vegetation, energy that 

would have been devoted to height growth may 

have been allocated to diameter growth, thereby 

enhancing light harvesting abilities for the 

pines. Furthermore, an increase in radiant 

energy may have indirectly affected nitrogen 

availability and root metabolism by elevating 

soil temperatures (Helms 1976). 

Although studies have indicated that soil 

moisture can be an important factor in pine 

performance (Sterrett and Adams 1977; Stone 

1980; Nelson and others 1981), moisture conditions were favorable during the 1982 growing 

season, and hence did not appear to be correlated with pine growth. Examination of 1983 

data, however, has indicated that moisture was 

a significant factor in pine growth under the 

drought conditions which prevailed over much of 

that growing season (Byrne and others, in 

press). 

Early pine growth was also enhanced by reduced volumes of competitive growth forms such 

as vines and trees. The well distributed root 

systems of vines could have increased the probability of direct below-ground interference 

with the pines, while allowing the vines access 

to a greater volume of soil as an alternative 

to the local resource depletion which may have 

resulted from this interference. Although 

direct shading of pine seedlings by vines was 

not observed, light is known to stimulate vine 

growth in disturbed habitats (Thomas 1980). 

The rapid growth rates conferred to vines by 

their efficient capture and use of light 

(Wechsler 19771, and their ability to compete 

below-ground with other early successional and 

established individuals (Boring and others 

1981; Whigham 1984) indicate the competitive 

potential of this growth-form. Although the 

relatively intact root systems of trees probably provided them competitive advantages similar 

of those of vines, canopy trees may also have 

been indirectly related to nitrogen availability by their inherent association with residual slash following harvest and low-intensity 

site preparation. 

Under the conditions of this experiment, the 

shear-pile-disk sequence achieved favorable 

conditions for first-year pine growth through 

reduction in vegetation volume (on drier sites, 

blocks B and C), selection against strong competitors, and an increase in light and nitrogen 

availability. Although the enhanced resource 

availability and reduction in competition did 

not cause statistically significant differences 

in pine growth, both root collar diameter 

growth and, in particular, height growth exhibited a tendency toward greater rates in DI 
plots. This trend was confirmed by 1983 data 

(S.V. Byrne, personal communication). Herbicide 

application caused only a slight and insignificant reduction in competing vegetation, but it 

was enough to significantly increase the availabilty of light and, in DI plots, nitrate, 

thereby accelerating root collar diameter growth. 

Although it is not obvious which direction of 

expansion is more favorable, early rapid diameter 

growth may result in faster canopy closure and 

thus earlier dominance of the site. 

It should be noted that these results do not 

necessarily foreshadow trends in long term 

productivity; several studies have shown that 

pine performance may decline on more intensively 

prepared sites over time (Keeves 1966; Whyte 

1973). However, intensive study of early pine 

performance in relation to the surrounding biotic 

and abiotic environment is useful for developing 

hypotheses concerning competitive interactions 

and, in the long run, the ecological mechanisms 

involved in the early phases of plantation 

development. 

LITERATURE CITED 

Allen, H.L.; Ballard, R. Forest fertilization 

of loblolly pine. In: R.C. Kellison and S. 

Gingrich, eds; Symposium on the lobiolly ecosystem, east region; North Carolina State 

University; 1983: 163-181. 

Bazzaz, F.A. The physiological ecology of plant 

succession. Annual Reviews of Ecology and 

Systematics 10:351-371; 1979. 

Boring, L.R.; Monk, C.D.; Swank, W.T. Early 

regeneration of a clear-cut southern Appalachian forest. Ecology 62: 1244-1253; 1979. 

Bormann, F.H.; Likens, G.E. Pattern and process in a forested ecosystem. New York: 

Springer-Verlag; 1979. 253 pp. 

Byrne, S. V.; Wentworth, T.R.; Nusser, S.M. A 

moisture strain index for loblolly pine. 

Canadian Journal of Forest Research; in press; 

1987, 

Cain, M.D.; Mann, Jr., W.F. Annual brush control 

increases early growth of loblolly pine. 

Southern Journal of Applied Forestry 4(2):67- 

70; 1980. 

Carter, G.A.; Miller, J.H.; Davis, D.E., and 

others. Effect of vegetative competition on 

the moisture and nutrient status of loblolly 

pine. Canadian Journal of Forest Research 

14: 1-9; 1984. 

Clason, T.R. Removal of hardwood vegetation increases growth and yield of a young loblolly 

pine stand. Southern Journal of Applied 

Forestry 2(3): 96-97; 1978. 

Cox, S.K.; Van Lear, D.N. Biomass and nutrient 

accretion on Piedmont sites following clearcutting and natural regeneration of lobiolly 

pine. In: Shoulders, Eugene, ed. Proceedings, Third Biennial Southern Silvicultural 

Research Conference; 1984 Kovember 7-8; 

Atlanta, GA. Gen. Tech. Rep. SO-54. Few 

Orleans LA: U.S. Department of Agriculture, 

Forest Service, Southern Forest Experiment 

Station; 1985: 501-506. 

Ehleringer, J.R. Implications of quantum yield 

differences on the distributions of C3 and C4 

grasses. Oecologia 31: 255-267; 1978. 

Evans, G.C. The quantitative analysis of plant 

growth. Berkeley and Los Angeles, CA: University California Press; 1972. 734 pp. 

Francis, C.A. Modifications of the ozalid paper 

technique for measuring integrated light 

transmission values in the field. Crop 

Science 10:321-322; 1970. 

Freeman, P.C.; Van Lear, D.H. Performance of 

eastern white pine and competing vegetation 

following two methods of stand conversion. 

Southern Journal of Applied Forestry 1(3):7-9; 

1977. 

Gabriel, K.R. The biplot graphic display of 

matrices with application to principal component analysis. Biometrika 58:453-467; 1971- 

Grime, J.P. Plant strategies and vegetation 

processes. New York: John Wiley and Sons; 

1979. 222 pp. 

Grime, J.P.; Jarvis, B.C. Shade avoidance and 

shade tolerance in flowering plants. 11. 

Effects of light on the germination of species of contrasted ecology. In: Evans, G.C.; 

Bainbridge, R.; Rackham, O., eds. Light as 

an ecological factor: 11; 16th Symposium of 

the British Ecological Society, Cambridge; 

1975: 525-532. 

.nes, B.L. Nitrogen uptake - apparent pattern 

during old field succession in the 

southeastern U.S. Oecologia 26:295-303; 

1977. 

Haines, L.W.; Maki, T.E.; Sanderford, S.G. The 

effects of mechanical site preparation treatments on soil productivity and tree (Pinus 

taeda L. and x. elliottii Engelm. var. 

elliottii) growth. In: Bernier, B.; Winget, 

C.H., eds; Forest soils and forest land 

management; Proceedings of Fourth North 

American Forest Soils Conference; Quebec, 

Canada; 1975: 379-395. 

Haines, L.W.; Pritchett, W.L. The effects of 

site preparation on the availability of soil 

nutrients and on slash pine growth. Proceedings of the Soil Science Society of Florida 

25: 356-364; 1965. 
Harper, J.L. Population biology of plants. Wechsler, N.R. Growth and physiological charNew York Academic Press; 1977. 892 pp. 

Helms, J.A. Factors influencing net photosynthesis in trees: an ecological viewpoint. 

In: Cannell, M.G.R.; Last, F.T., eds; Tree 

physiology and improvement; Academic Press, 

London; 1976:55-78. 

11 0 The development of flora in evenaged plantations. In: Ford, E.L; Malcolm, 

D.C.; Atterson, J., eds; The ecology of evenaged plantations; Proc IUFRO; Edinburgh, 

Scotland; 1979: 175-192. 

Keeves, A. Some evidence of loss of productivity with successive rotation of Pinus radiata 

in the South East of Australia. Australian 

Forester 30: 51-63; 1966. 

Nelson, L.R.; Pedersen, R.C.; Autry, L.L.; and 

others. Impacts of herbaceous weeds in young 

loblolly pine plantations. Southern Journal of 

Applied Forestry 5(3): 153-158; 1981. 

Ross, M.A.; Harper, J.L. Occupation of biological space during seedling establishnent. 

Journal of Ecology 60: 77-88, 1572. 

SAS Institute, Inc. SAS User's Guide: Statistics. 

Gary, NC; SAS Institute, Lnc.; 1982, 584 pp. 

Schultz, R.P. Environmental change af ter site 

preparation and slash pine planting on a flatwoods site. USDA Forest Service Research 

Paper; SE-156; 1976. 20 pp. 

Smith, B.N.; Brown, W.V. The Kranz syndrome in 

the Gramineae as indicated by carbon isotopic ratios. American Journal of Botany 

60:505-513; 1973. 

Sterrett, J.P.; Adams, R.E. The effect of forest 

conversion with herbicides on pine (Pinus 

spp.) establishment, soil moisture and understory vegetation. Weed Science 25: 521-523; 

1977. 

stone, D.M. Survival and growth of red pine 

planted on a hardwood site - a second look. 

Forestry Chronicle 58: 112-114; 1980. 

Thomas, LL, Jr. The impact of three exotic 

plant species on a Potomac island. National 

Park Service Scientific Monograph Service; 

U.S. Department of Interior; Washington, DC; 

NO* 13. 1980. 

Tippen, T., ed. Proceedings: a symposium on 

principles of maintaining productivity on prepared sites. Southeastern Area State and 

Private Forestry; Atlanta, GA; 1978. 171 pp. 

Vitousek, P.M.; Matson, P.A, Mechanisms of nitrogen retention in forest ecosystems: a field 

experiment. Science 225: 51-52; 1984, 

acteristics of Kudzu, Pueraria lobata 

(Willd.) Ohwi, in relation to its competitive 

success. Athens, GA: University of Georgia; 

1977, Thesis. 

Whigham, D. The influence of vines on the 

growth of Liquidambar styracilua L. 

(swee tgum). Canadian Journal of , Forest 

Research 14:37-39; 1984. 

Whyte, A.G.D. Productivity of first and second 

rotation crops of Pinus radiata on the 

Moutere gravel soils 'of Nelson. New Zealand 

Journal of Forestry 18:87-103; 1973. 
IMPACT OF INTENSIVE COMPETITION MANAGEMENT 

1 / ON DOMINANT STAND HEIGHT - 

2 i G. Daniel Ayers, Terry R. Clason, and William D. Smith - 

Abstract.--One loblolly pine spacing study and three 

vegetative management studies were used to evaluate the impact 

of intra-specific and inter-specific competition on dominant 

stand height. The pine spacing study exhibited a strong 

dominant height-pine density relationship from ages 13 to 33. 

Dominant height at age 33 was 16 feet greater in the widest 

spacing than in the narrowest spacing. Yield estimation biases 

had an absolute range of 26.5 percent when the dominant 

height-density relationship was ignored. This translated to 

total volume (i.b.) bias ranging from 468 ft3 per acre 

under-estimation to 528 ft3 per acre over-estimation. All 

vegetation management studies revealed a significant response to 

hardwood and herbaceous vegetation control. Total vegetation 

control elicited the greatest reponse in dominant height. 

INTRODUCTION 

Dominant height (DH) is more closely 

related to the wood producing capacity of a 

timber site than any other single stand measure. 

It is also the stand measure least affected by 

sivlicultural practices. Consequently, dominant 

stand height is the foundation for our present 

day site index (SI) model. SI, in turn, is the 

driving variable for most contemporary growth 

and yield models. 

Height as a site classification tool has 

been used, at least in Germany, since 1908 (Roth 

1916). Height classes ranged from 3 to 5 and 

differences between classes were generally 

greater than 10 feet. In the southern U.S., 10- 

feet SI classes based on dominant height have 

been'use in growth and yield prediction (Shumacher and Coile 1960). Although DH is the 

stand variable least affected by silvicultural 

treatments, these treatments do elicit some 

response. When do these reponses significantly 

affect site classification and growth and yield 

predicit ion? 

Lloyd and Jones (1982) found a significant 

relationship between DH and pine density. They 

also demonstrated that prediction biases were 

significant and cumulative over time when the 

DH-density relationship was ignored in growth 

estimation. Although much research has been 

directed towards quantifying effects of hardwood 

and herbaceous competition on pine stand 

development, specific effects on DH have not 

been reported. Because pine density 

(intra-specific competition) significantly 

affects DH, hardwood and herbaceous 

(inter-specific) competition should cause 

similar responses. 

The objectives of the following analyses 

were: to support the existence of a significant 

DH-pine density relationship; to demonstrate 

that ignoring this relationship can result in 

considerable yield prediction bias; and to show 

that a significant relationship between DH and 

inter-specific competition exists at an early 

age. 

EXPERIMENTAL DATA 

L1paper presented at the Fourth Biennial Southern Silvicultural Research Conference, 

Atlanta, Georgia, November 4-6, 1986. 

1'~uthors are Research Associate and 

Associate Professor, Hill Farm Research Station, 

Louisiana Agricultural Experiment Station, LSU 

Agricultural Center, Homer, LA 71040, and 

Lecturer, School of Forest Resources, North 

Carolina State University, Raleigh, NC 27695, 

respectively. 

2'~~~roved for publication by the Director of 

the Louisiana Agricultural Experiment Station as 

manuscript number 86-80-0369. 

Because DH and site quality are so closely 

related, DH responses to intra-specific and 

inter-specific competition can be difficult to 

isolate. Spacing and vegetative management 

experiments with randomized complete block designs and uniform within-block site characteristics are necessary for this purpose. 

DOMIMAWT HEIGHT AND INTRA-SPECIFIC COMPETITION 

The DH-pine density relationship was 

examined using a 37-year-old loblolly pine 

spacing study located at the Hill Farm Research 
Station in Homer, LA. Spacing treatments were 

4x4, 6x6, 6x8, 8x8, and 10x10 feet. The 10x10 

spacing treatment had one replication, while the 

other treatments were replicated twice. 

DH was defined as the average height of the 

tallest 40 percent of the standing trees in each 

plot * 

Stocking was defined for each spacing at 

age 13, 18, 21, 22, 25, 28, 29, and 33 (Table 

1). Mortality was highest in the 4x4 spacings. 

Generally, mortality decreased with increased 

spacing. From age 13 to 25, mortalities for the 

4x4, 6x6, 6x8, 8x8, and 10x10 treatments were 

45, 27, 25, 12, and 9 percent, respectively. 

From age 25 to 33, mortalities increased for the 

respective spacings to 50, 45, 27, 42, and 22 

percent, 

DH for each measurement age and spacing is 

summarized in Table 2. We assumed that the 

relationships evident in this table were due to 

density effects on DH and not on differences in 

site quality. Our data support this assumption. 

If site quality was significantly different 

among treatments, we would expect greater 

irregularity in responses from the various 

treatments before age 10. This was not evident. 

Height growth, as measured by average height of 

the 100 largest diameter trees per acre (top 

height), was close across spacings until age 10. 

By age 10, intra-specific competition was well 

advanced in the 4x4 treatments and the wider 

spacings had markedly higher top heights. At 

age 9, top height was 28.0, 29.9, 28.3, 29.2, 

and 29.4 feet for the 4x4, 6x6, 6x8, 8x8, and 

10x10 spacings, respectively. .By age 10, top 

height was 30.8, 33.7, 32.2, 34.0, and 33.9 feet 

for the respective treatments. 

Analysis of variance (ANOV) of DH of the 

various treatments was generally not significant 

(p 2 0.05) , although r2 values were greater than 

0.80, except for age 25 which exhibited an r2 of 

0.70. However, least significant difference 

(LSD) mean comparisons and orthogonal polynomial 

contrasts revealed some consistent differences. 

In all years, LSD comparisons detected 

significant differences between the 4x4 and 

10x10 spacings. LSD groupings did not 

differentiate between the 4x4, 6x6, 6x8, 

and 8x8 spacings, but orthogonal contrasts 

revealed a significant difference between the 

4x4 spacing and the combined average of all 

other spacings. The 6x6, 6x8, and 8x8 spacings 

were never signifcantly different. From age 18 

to age 33, the 10x10 spacing exhibited a DH at 

least 6.5 feet greater than all other spacings. 

Although these differences were large, LSD and 

orthogonal contrasts detected no significant 

differences among the 6x6, 6x8, 8x8, and 10x10 

spacings. It is important to note that height 

advantages achieved at an early age were maintained to age 33. 

Table 1.--Number of trees per acre by spacing 

and age, l-/ 

Planting spacing (ft x ft) 

----------- Trees per acre----------- 

13 1730 856 672 58 7 383 

18 1658 854 672 58 1 383 

2 1 1366 775 620 541 37 1 

22 1232 752 590 532 359 

2 5 948 626 502 516 347 

28 723 550 4-41 486 323 

29 676 526 438 470 299 

33 472 345 366 299 269 

L'values shown are averages of two blocks 

except for the 10x10 spacing with one 

replication. 

Table 2.--Mean total height of the tallest 40 

percent of plot trees by spacing and age. _L/ 

Planting spacing (ft x ft) 

L'values shown are averages of two blocks 

except for the 10x10 spacing with one 

replication. 

The results of linear regressions of the 

natural logarithm of DH as the dependent 

variable, and the inverse of the number of trees 

per acre as the independent variable, are shown 

in Table 3. R~ values ranged from 0.56 to 0.82. 

All regressions were highly significant (p I 

0.01) except for age 33. The regression model 

and slope parameter for age 33 was significant 

at the 0.05 level. 
Table 3.--Linear regression models and r2 values 

for predicting the natural log of dominant 

height from the inverse of the number of trees 

per acre. 

Age Intercept Slope r 

L'Model and parameters highly significant 

(p 6 0.01). 

L/Intercept highly significant (P S 0.01) , model and slope parameter significant (p6 0.05). 

YIELD PREDICTION BIAS 

The DH values in Table 2 were used to 

estimate SI (base age 25) for each spacing-age 

combination using the equation discussed in 

Golden et al. (1981) (Table 4). Since total 

volume per acre is a function of age, SI, and a 

measure of stand density, yield models will 

predict well for any given age, SI, and density 

combination. However, growth and yield estimation assumes a constant SI over time. The pine 

density effects on SI estimation in Table 4 

indicate that yield estimation based on a 

constant SI will result in biased estimates. 

We evaluated the degree of bias in yield 

estimates based on our data using the North 

Carolina State University loblolly pine growth 

and yield simulator (Smith and Hafley 1986). 

Yields were estimated using the observed site 

indices in Table 4 and the observed age and 

density for each spacing-age combination. These 

yields reflect the effects of density on DH. A 

second set of yields was estimated from the same 

age and density parameters as above but using a 

constant SI. The constant SI selected was 69 

feet, which was the average DH over all spacings 

at age 25. 

The results of subtracting yields (actual) 

using observed site indices from yields 

(predicted) using the constant SI are shown in 

Table 5. The differences ranged from underestimation of 468 ft3 per acr6 for the 10x10 

spacing at age 25 to over-estimation of 528 ft3 

per acre for the 6x6 spacing at age 33. As a 

percent of actual yields, the biases ranged from 

-10.1 to 16.4 percent (Table 6). The amount of 

bias is directly proportional to the differences 

between SI estimates that reflect a density 

relationship and the constant SI. 

Table 4.--Site index estimates by spacing and 

age. I/ L/ 

Planting spacing (ft x ft) 

------- Site index base age 25 (ft)------- 

64.4 67.5 67.4 69.5 72.0 

62.2 64.6 64.8 65.2 73.4 

62.6 67.4 67.2 67.9 74.9 

61.8 66.4 66.6 66.7 75.6 

63.5 69.0 68.7 67.4 76.8 

60.4 66.3 66.8 65.5 74.2 

62.0 67.3 67.3 65.4 75.0 

59.4 66.1 67.4 64.4 73.5 

LiSite index estimates from equation 

developed by Golden et al. (1981). 

L'Values shown are averages of two blocks 

except for the 10x10 spacing, which had one 

replication. 

Table 5.--Total cubic foot volume (i.b.) yield 

estimation biases from ignoring the dominant 

height-pine density relationship. _L/ 

Planting spacing (ft x ft) 

Age 4x4 6x6 6x8 8x8 10x10 

Cubic foot volume per acre-------- 

13 11 1 4 7 4 3 -23 -63 

18 206 164 15 9 16 7 -161 

2 1 186 9 1 9 4 4 9 -295 

2 2 2 2 3 14 1 9 3 103 -353 

2 5 176 0 0 121 -468 

2 8 369 181 121 209 -333 

2 9 295 130 2 7 289 -394 

3 3 48 9 528 129 354 -344 

L'Yields predicted using North Carolina State 

Univ, loblolly pine growth and yield simulator 

as discussed in Smith and Hafley (1986). 
Table 6.--Percentage by which yields were underor over-estimated when the height-pine density 

relationship was ignored. 

Planting spacing (ft x ft) 

Age 4x4 6x6 6x8 8x8 10x10 

DOMINANT HEIGHT AND INTER-SPECIFIC COMPETITION 

Three vegetative management studies were 

used to evaluate early effects of inter-specific 

competition on DH. The first, located on the 

Hill Farm Research Station in Homer, LA, had 

three blocks and five treatments. The 

treatments were: no vegetation control, one year 

of Velpare, two years of Velpar@, one year of 

Oust@, and two years of Oust@. The study was 

established in 1981 with a planting spacing of 

8x8 feet (681 trees per acre). The second and 

third studies were located at Aycock and 

Winnfield, LA. Four replications of four 

treatments were established in 1984 at a 

planting spacing of 8x8 feet. The treatments 

were: no vegetation control, herbaceous control 

only, hardwood control only, and total 

vegetation control. 

Homer Vegetation Management Study 

The average height of the tallest 100 trees 

per acre by treatment for four growing seasons 

are depicted in Table 7. Averages in 1981 were 

from initial heights. R~ values of analysis of 

variance (ANOV) ranged from 0.74 to 0.90, which 

were significant. Overall treatment effects 

were not significantly different. However, LSD 

mean comparisons detected significant 

differences in DH response between no vegetation 

control and the other treatments for all growing 

seasons except 1984. Oust treatments generally 

had a greater effect on DH than Velpar 

treatments, This may indicate that herbaceous 

weed control promotes DH growth better than 

hardwood control, at least at an early age. 

Avcock and Winnfield Com~etition Im~act Studies 

Tables 8 and 9 depict DH after one and two 

growing seasons for the Aycock and Winnfield 

studies, respectively. For both locations, ANOV 

model and treatment sums of squares were highly 

significant in all growing seasons. 

After one growing season at Aycock, LSD 

mean comparisons detected no significant 

difference between DH response to no vegetation 

control and herbaceous vegetation control only. 

DH in hardwood control treatments was 

significantly higher than in the above two 

treatments, while total vegetation control 

resulted in a significantly higher DH than all 

other treatments. 

After one growing season at Winnfield, LSD 

mean comparisons gave the same results as at 

Aycock. After two growing seasons, DH response 

from herbaceous only and hardwood only 

treatments had reversed. Herbaceous control 

exhibited a significantly larger DH than did 

hardwood control. This supports the results of 

the Homer location. Thus, the response of DH to 

different levels of inter-specific competition 

was significant at an early age. 

Table 7.--Mean height of the tallest 100 trees 

per acre by year and treatment for the Homer 

Vegetation Management Study. l-/ 

2 / Treatment - 

No Velpar Velpar Oust Oust 

Year control 1 year 2 years 1 year 2 years 

3, -------------- Height (ft)--------------- 

1981 - 0.5 0.5 0.5 0.5 0.4 

L'values shown are averages of four blocks. 

L'Means with the same letter are not 

significantly different (p d 0.05). 

2'~rom initial planting heights. 
Table 8.--Mean height of the tallest 100 trees 

per acre by year and treatment for the Aycock 

Competition Impact Study. L/ 

2 / Treatment - 

No Herbaceous Hardwood Total 

Year control control control control 

LI~alues shown are averages of four blocks. 

/~eans with the same letter are not 

significantly different (p 6 0.05). 

'~rom initial planting heights. 

Table 9.--Mean height of the tallest 100 trees 

per acre by year and treatment for the 

Winnfield Competition Impact Study. l-/ 

2 1 Treatment - 

No Herbaceous Hardwood Total 

Year control control control control 

?-'~alues shown are averages of four blocks. 

YMeans with the same letter are not 

significantly different (P I 0.05). 

2'~rom initial planting heights. 

Data from four studies showed that intraand inter-specific competition significantly 

reduced DH. The inverse relationship between 

pine density and DW in lobfolly pine was similar 

to that reported for slash pine by Lloyd and 

Jones (1982). The DH-pine density relationship 

is long term, Failure to recognize this 

relationship in growth and yield prediction can 

seriously bias yield estimations. 

Our data showed a significant inverse 

relationship between inter-specific competition 

and DK at an early age, But long term 

speculation about these effects would be 

premature. However, this early evidence does 

encourage continued research into the long term 

effects of Inter-specific competition on 

DN . 

Despite the problems we have discussed, DN 

remains our best measure of site quality and is 

the parameter least affected by silvicultural 

practices. The latter fact makes DH superior to 

total volume as a measure of site productivity. 

Continued research is needed to define a site 

index measure that reflects the interaction 

between dominant height and intra- and interspecific competition. Until such an index is 

defined, foresters should remain cognizant of 

the fact that growth and yield estimations are 

not as precise as modeling techniques might lead 

one to believe. 

LITEMTURE CITED 

Golden, M.S., R. Meldahl, S.A. Knowe, and W.D. 

Boyer. 

1981. Predicting site index for oldfield loblolly pine plantations. South. 

Jour. Appl. For. 5(3):109-114. 

Lloyd, F.T., and E.P. Jones, Jr. 

1982. Density effects on height growth and 

its implications for site index prediction 

and growth prediction. In Proceedings: 

Second Biennial South. SIlv. Res. Conf., 

Atlanta, GA. p. 329-333. 

Roth, %. 

1916. Concerning site. For. Quart., Vok. 

X14, p. 3-13. 

Shumacher, F.X., and T.S. Coile. 

1960. Growth and yield of natural stasds of 

the southern pines. T,S. CoiLe, Inc, 115 9, 

Smith, W.D,, and W.L, Wafley. 

1986. Evaluation of a loblolly pine 

plantation thinning model. South, Jour. 

Appl. For. 10(1):52-63, 
A REGION-WIDE STUDY OF LOBLOLLY PINE SEEDLING GROmH 

1 / RELATIVE TO FOUR COMPETITION LEVELS AFTER TWO GROWING SEASONST 

2 / James H. Miller and Bruce Zutterand 

Shepard M. Zedaker, Michael Cain, M. Boyd Edwards, G. Kenneth Xydias, 

A.R. Applegate, R. Lee Atkins, Sam Campbell, Edward Daly, 

Charles Hollis, Steven A, Knowe, and Jeff Paschke 

Abstract.--A common study design was simultaneously 

established at 13 locations in the Southern United States to 

examine the scope of regional variation in loblolly pine 

(Pinus -- taeda L.) growth relative to four competition levels. 

The following competition levels were created and maintained 

for 2 years using selective herbicides and directed applications of nonselective herbicides: (a) complete control of 

all competition; (b) woody control, leaving the herbaceous 

competition; (c) herbaceous control, leaving the woody 

competition; and (d) no control, with both herbaceous and 

woody competition. Effects on planted pines are being 

examined at 12 locations, and natural regeneration is being 

studied at one Arkansas location. 

During the first 2 years the herbaceous component 

generally had more negative influence on pine growth than 

the woody component. Diameter growth was more often 

influenced than height growth. The size of trees grown 

without competition represents unique benchmarks of growth 

across the region by which results from other vegetation 

management studies can be gauged. 

L/Paper presented at Southern Silvicultural 

Research Conference, Atlanta, Georgia, November 

4-6, 1986. 

?/~uthors are Research Forester, Southern 

Forest Experiment Station, USDA Forest Service, 

Auburn, AL; Research Associate, Auburn 

University Silvicultural Herbicide Cooperative, 

Auburn, AL; Assistant Professor, Virginia 

Polytechnic Institute and State University, 

Blacksburg, VA; Research Forester, USDA Forest 

Service, Southern Forest Experiment Station, 

Crossett, AR; Research Ecologist, USDA Forest 

Service, Southeastern Forest Experiment Station, 

Macon, GA; Research Forester, Continental Forest 

Investments, Savannah, GA; Research Forester, 

Packaging Corp. of America, Counce, TN; 

Development Representative, E. I. Du Pont 

de Nemours & Co., Inc., Natchez, MS; Research 

Forester, Scott Paper Company, Saraland, AL; 

Research Forester, International Paper Company, 

Natchez, MS; Section Leader, International Paper 

Company, Bainbridge, GA; Research Forester, 

Cavenham Forest Industries, Bogalusa, LA; 

Management Forester, Potlatch Corporation, 

Warren, AR. 

INTRODUCTION 

Early in the life of pine plantations, an 

array of woody and nonwoody vegetation competes 

at various levels across the landscape with 

individual crop seedlings. If all nonarboresent 

vegetation is considered as herbaceous, then the 

array of woody and herbaceous vegetation and the 

resulting pine growth can be conceptually viewed 

as a response surface (fig. I). Woody and herbaceous competition are the X and Y variables 

and pine size is the response variable, Z. 

Vegetation management treatments are applied to 

shift the amounts of these components to areas 

on the response surface where more favorable 

pine growth will occur. Unfortunately, very few 

areas on this response surface have been 

investigated, and only on a few sites, often 

using different types and timings of treatments. 

Knowing some key responses across many sites on 

this surface should allow scattered research 

findings to be compared to these knowns and thus 

to each other. 
NO 

PlNE 

VOLUME 

(Zf 

COMPLETE OTAL HERBACEOUS 

CON1 ROtl WOODY (X) -+ 

Figure 1.--Conceptual response surface showing the 

four corners studied in the Com~etition 

Omission Monitoring Project 

In 1982, at the Second Southern Silvicultural 

Research Conference, a group of investigators met 

and began planning a project to define the four 

corners of this response surface. The primary 

study objective was to establish a southern 

region framework of growth response on major soil 

sites for newly established loblolly pine 

relative to four competition levels: (1) no 

control, (2) hardwood and shrub (woody) control, 

(3) herbaceous control, and (4) total competition 

control. These control levels are to be maintained for at least 4 years. A second objective 

was to make a strict comparison between the 

relative importance of herbaceous vs. woody 

competition as they affect loblolly pine growth 

on a wide range of sites. Measurements of plant 

moisture stress were to be made on two locations 

to aid in data interpretation. A third objective 

was to describe both the herbaceous and woody 

vegetation at each location to identify the 

principle competitors in the region. 

This cooperative effort has since been termed 

the Competition Omission Monitoring Project or 

COMP, because selected components are omitted and 

pine response is closely monitored. Sixteen 

sites have been established using a common study 

plan, with some minor alterations. The 2-year 

results from 13 locations established in 1984 are 

presented in this paper. 

METHODS 

Study Locations 

Study locations are shown in figure 2 and physiographic provinces noted in table 1. Locations 

were clearcut in late 1982 or 1983, except for 

Crossett, BR, and Pembroke, GA. At Crossett, 

hardwoods greater than 1 inch in d.b.h. were 

injected with herbicide in 1980 prior to a seedtree regeneration cut (1981); then brush cutting 

to a height of 2.5 feet occurred before seed tree 

removal (1983). At Pembroke, a 6-year old 

plantation that had burned in a wildfire was 

rebedded in 1983, the only bedded study location. 

Figure 2.--Study area locations 

The other sites were chopped and burned in 1983, 

except for Atmore, AL, which was fuelwood 

harvested and Counce, TN, which was sheared and 

windrowed. At some locations, chain saws and 

tree injection were used to remove scattered 

standing trees after site preparation. 

Plot Establishment and Treatment 

Sixteen treatment plots measuring 104 by 104 ft 

(0.25 acres) were established at most locations 

using a randomized complete block design with 

four blocks of four plots. At Bainbridge, GA, a 

completely randomized design was used, and at 

Pembroke, GA, 20 plots were established with 5 

blocks of 4 plots. All blocking was by 

topography except at Crossett, AR, and all slope 

positions were included except the medium to 

steep slopes. Blocking at Crossett was by pine 

stocking levels. 

Interior measurement plots were 63 by 63 ft 

(0.09 acres), which accommodated precisely 

positioned planting spots measured at 9 by 9 ft, 

except at the natural regeneration and bedded 

sites. Thus there were 121 planting spots within 

the 0.25-acre treatment plots and 49 spots within 

the measurement plots. At each planting spot, 

two 1-0 loblolly pine seedlings were planted 

within 5 inches of the spot marker. Double 

planting was performed to assure full stocking 

for long-term growth measurements. Either 

improved or Livingston Parish seedlings were 

planted. After the first growing season, 

randomly generated codes were used to thin 

seedlings to one per spot. This was done to 

maintain population means and variance's of 

initial seedling size, All 49 measurement 

seedlings were permanently identified. For the 

natural regeneration study location at Crossett, 

AR, 50 seedlings on each plot were randomly 

selected and tagged for measurements. 
Table 1.--Location, physiographic province, soil series, and soil properties for two depths for 

each study site 

Available 

Locat ion Province Soil Series Depth Sand Silt Clay OM Po4 PH 

Crossett, AR HCP' Bude , Providence 0-6 35 51 14 2.5 0.13 5.4 

6-24 33 51 16 0.7 0.03 5.1 

Warren, AR HCP Saffell, Stough 0-6 59 30 11 3.7 2.23 5.7 

6-24 57 28 15 1.9 0.90 5.1 

Jena, LA MCP Cameran, Anacoco 0-6 55 34 11 2.7 0.36 5.3 

6-24 46 30 24 1.1 0.03 5.2 

Liverpool, LA MCP Tangi, Providence 0-6 39. 49 12 3.0 0.25 5.2 

6-24 35 46 19 2.2 0.13 5.2 

Liberty, MS MCP Saffell 

Counce, TN HCP Silerton, Lutts 0-6 9 54 37 2.2 0.10 4.9 

6-24 8 51 41 1.1 0.05 4.9 

Atmore, AL MCP Orangeburg 

Tallassee, AL HCP Cowarts 

Camp Hill, AL P Cecil, Pacolet 0-6 72 17 11 2.1 0.43 5.4 

6-24 61 16 23 0.8 0.05 5.3 

Bainbridge, GA MCP Orangeburg, Esto 0-6 86 5 9 0.9 0.90 5.8 

6-24 79 4 17 0.9 0.20 5.4 

Monticello, GA P Davidson 

Pembroke, GA LCP Mascottee, Pelham 0-6 88 6 6 3.1 0.38 4.3 

6-24 88 7 5 1.9 0.33 4.5 

Appomattox,VA P Cecil, Cullen, 0-6 42 34 24 3.8 0.85 4.9 

Iredell 6-24 32 26 42 1.5 0.16 4.7 

l~~~=~illy Coastal Plain, MCP=Middle Coastal Plain; LCP-Lower Coastal Plain; P-Piedmont 

The four treatments, or desired competition Herbaceous control (herb control)--March 

situations, were established and maintained as to May applications of sulfometuron 

£01 lows : methyl (Oustm) at 3 to 6 oz product per 

No control (none)--After the initial site 

preparation treatment, no further broadcast treatments were applied. Vine 

infestations were spot treated at most 

locations using shielded directed sprays 

of glyphosate (~oundup") or wick applications and directed sprays of triclopyr 

(Garlonm). 

Woody control--Preestablishment herbicide 

applications of foliar and basal sprays 

were used. For two growing seasons, 

three to six herbicide treatments were 

applied to eliminate individual hardwood 

stems and vine infestations using 

directed sprays of glyphosate and/or 

tricloypr and basal wipes of triclopyr. 

Foliar-active herbicides were used to 

minimize seedling damage. 

acre were the main control treatments. 

In the second year, glyphosate at 18 oz 

product per acre or oxyfluorfen (Goalm) 

at 0.6 gal product per acre were included 

in a tank mix with sulforneturon methyl. 

At three to five times during a growing 

season, shielded directed sprays of 

glyphosate (2-percent solution) were applied to scattered regrowth. At 

Crossett and Bainbridge, sethoxydim 

(Poastm) was used as a broadcast spray 

for grass control. 

~otar control--A combination of treatments used on the woody and herbaceous 

control plots were applied as outlined 

above. 
Through careful applications, minimum pine 

damage occurred within the plots. 

Measurements and Analyses 

Study sites were located on prevalent series 

for the provinces and some locations are on 

common series (table 1). Soils were sampled in 

early spring of 1984 on all plots to characterize 

sites. Twenty tube (I-inch diameter) samples per 

plot were composited by depth; 0 to 6, 6 to 12, 

and 12 to 24 inches. A range of textural classes 

are encompassed by the study sites with most 

surface soils being in the loamy classes with 

medium to high sand contents. The exception is 

Counce, TN, which is a silty clay loam. 

Surface soil organic matter (OM) ranges from 0.9 

to 3.8 percent, available phosphorus from an 

extremely low level at 0.07 mg/kg to a high of 

2.23 mg/kg, and pH from 4.3 to 5.8. 

Seedlings were measured during the winter after 

the first two growing seasons. Heights and 

groundline diameters (GLD's) were measured the 

first year, and diameter at 6 inches above 

groundline (D6) was included the second year. 

Damage incidence by tipmoth (Rhyacionia spp.) and 

fusiform rust (Cronartium quercuum (~erk.) Miyabe 

ex Shirai f,s~. fusiforme) were recorded bv stem 

location for all seedlings. 

Competition levels were assessed in September 

for the first two growing seasons to document the 

variation in competitive species across the 

region and the degree of treatment success. 

Woody rootstocks were counted by species and by 

1-ft height categories on three systematically 

located 9- by 18-ft plots per measurement plot. 

These 9- by 18-ft plots were halved and 

herbaceous components (grasses, forbs, semiwoody 

vines, and shrubs) and bare ground were visually 

estimated by percent cover on the six 9- by 9-ft 

plots. Herbaceous species having a cover greater 

than 15 percent were recorded. In the second 

growing season, additional cover estimates were 

made for woody competition and crop pines. At 

Pembroke, GAY 11- by 15-ft plots centered on the 

11-ft spaced beds were used instead of the 9- by 

18-ft plots. At Crossett, AR, rootstock counts 

and cover estimates were made on 10 circular 

milacre plots per measurement plot. 

Pine growth data, tipmoth and fusiform 

incidence, and competition cover estimates were 

analyzed separately by location using the 

appropriate analysis of variance (ANOVA) with 

arcsine square-root transformations for percent 

data. If treatments were significantly different 

at the 0.05 level, treatment means were separated 

using Duncan's multiple range test, 

Pine Moisture Stress 

To delve closer into cause-and-effect relations 

between competition and its influence on moisture 

stress of pine seedlings, in late-September 1984, 

predawn moisture stress was taken on the pines at 

Tallassee and Camp Hill, AL. These locations 

were planted with seedling from the same source, 

on sites located within 30 miles of each other, 

representing Coastal Plain (Tallassee) and 

Piedmont (Camp Hill) soils. The pressure chamber 

method (Waring and Cleary 1967) was used on two 

consecutive mornings after a rainless period of 

about 20 days. Seedling lateral branches were 

clipped and xylem pressure potential (XXP) was 

read in negative megapascals (MPa). Eight 

seedlings were randomly selected from each of the 

four treatments on two blocks at each location. 

Plot means were then calculated. After inspection for homogenity, the data from both locations 

were combined and analyzed using ANOVA and 

Duncan's multiple range test. Linear regression 

techniques were used to explore the relation between xylem pressure potential and first-year GLD. 

RESULTS 

Woody and Herbaceous Species Composition 

Panicum grasses were common at nine locations 

in the first year with broomsedge being the 

second most common grass across the region 

(table 2). These grasses generally increased in 

frequency and percentage of cover in the second 

year. The asteraceae forbs (asters, horseweed, 

dogfennel, goldenrod, etc.) played a conspicious 

role in early succession, with member species 

present but differing by iocation and by year. 

Blackberry was a component at most Locations on 

the no control and herb control treatments. Like 

blackberry, honeysuckle and other vines increased 

coverage in the second year. 

Sumacs were the most common woody species. The 

range of wood species and percent composition was 

fairly unique by location. The study locations 

represent a wide spectrum in the abundance of 

woody competition, and densities were greater 

than 3,000 rootstocks per acre at most locations 

in the second growing season. 

Cover Estimates 

The success of control treatments can be judged 

by the cover estimates for the first and second 

growing seasons shown in table 4. Coverage the 

second year may total to more than 100 percent of 

the area because the herbaceous, woody, and pine 

covers can simultaneously occupy different aerial 

strata. The specified competition levels have 

been reached at most locations, with yearly 

improvements being made toward the absolute competition levels. In general, the percent bare 

ground in table 4 shows good overall control on 

total control treatments, considering the amount 

of competition controlled and the effort 

expended. Early season control of herbaceous 

vegetation in the first year was nearly complete 

at most locations following the pre-emergent 

herbicide applications. The late-season cover 

values in table 4 do not reflect this degree of 

control due to some subsequent regrowth of 

grasses and vines. 
Table 2.-The percent frequency and cover of prevalent herbacecus species m no control plots in the first and secorrd year aid 

percent percent percent percent 

blackberry 

honeysuckle 

greenbriar 

uniola grass 

winged smc 

hucklekrry 

sassafras 

panicum grass 

panicum grass 

broausedge 

dogfennel 

horseweed 

winged smc 

bitternut hickory 

white oak 

willow 

panictan grass 

crotonopsis 

broomedge 

Jena, LA 

panicum grass panicum grass 

dogfennel 

blackberry 

commtn lespedeza 

loblolly pine 

winged smc 

scxlthern red oak 

beauty berry 

dogfennel 

woolly croton 

blackberry 

Liverpool, LA 

broomsedge 83 29 panicum grass 100 20 waxmyrtle 19 5,243 

panicum grass 79 15 brwmsedge 92 28 huckleberry 16 

aster 42 4 goldenrod 54 5 winged smc 14 

goldenrod 42 3 rushes 46 5 blackgum 10 

Liberty, MS 

blackberry 71 11 winged smc 49 7 ,a3 

no 

data 

partridge pea 54 

goldenrod 46 

honeysuckle 46 

water 

- 

oak 

sweetgum 

Counce, 734 

~GI-~LC~ gr~3.W 1% -- 15 pania gas loo 

brwmsedge 100 

bmese t 46 

nutsedge 25 

winged smc 

blackgum 

post oak 

bitternut hickory 

67 8 

falsedandelion 46 4 

nutsedge 21 2 

Atmore, AL 

panicum grass 100 47 

southern dewberry 71 12 

panicum grass 100 

blackberry 58 

brwmsedge 42 

southern dewberry 29 

&~llberry 

staghorn smc 

persk 

blackberry 50 5 

brmedge 37 3 

Tallassee, AL 

dogfennel 63 1 broomsedge 63 11 swee tgum 51 3,944 

ccmmn lespedeza 42 10 panicum grass 58 9 water oak 21 

piwed 33 5 dogfennel 58 8 waxmyrtle 8 

horseweed 29 5 horseweed 33 7 huckleberry 3 

Camp Hill, AZ, 

panicum grass 

partridge pea 

goldenweed 

r%w=d 

Bainbridge, G4 

horseweed 

greenbriar 

partridge pea 

tnntpet creeper 

60 panicum grass 

10 aster 

8 horseieed 

5 broomsedge 

winged sac 

smth smc 

water oak 

swee tgum 

12 dog fennel 

5 partridge pea 

5 blackberry 

13 greenbriar 

sassafras 

winged smc 

me tgum 

water oak 

Manticello, GA 

ericanbumd 79 13 nutsedge 58 12 s~rmth surmc 64 7,350 

dogfennel 

honeysuckle 

little bluestein 

Pembroke, GA 

@cum grass 

broomsedge 

bset 

wiregrass 

Amttox, VA 

horseweed 

panicum grass 

med 

american burmeed 

little bluestem 

goldenrod 

boneset 

metgerm 

water oak 

panicum grass 

broomsedge 

beset 

wiregrass 

gallberry 

huckleberry 

sweetbay 

cud joe 

desmdium 

strawberry 

blackberry 

panicum grass 

winged smc 

yellow poplar 

smoth sac 

d 
Table 3. and scientific names of species discussed in the text 

Scientific Scientific 

Herbaceas Species Woody Species 

Am. bud 

asters 

blackberry 

crabgrass, hairy 

crotonupsis 

dedium 

dog fenne 1 

falseddelians 

goldenrod 

goldenweed 

griffre* c- greenbriar 

hmeysuckle 

horswed 

Hypericurns 

lespedeza, camm 

little bluestem 

nutsedge 

panicum grass 

partridge pea 

pinewed 

rushes 

southern dewberry 

strawberry 

trumpet creeper 

uniola grass 

wiregrass 

wooly croton 

Erichtites hieracifolia L. 

Aster spp. 

SPP 

Eupatarium spp. 

Andropogan virginicus L. 

Digitaria sanguinalis L. 

Crotonopsis elliptica Willd. 

&dim spp. 

Eupatorium capillifolium Lam. 

s carolinianus (Walt .) 

Solidago spp. 

Polypream pr&s L. 

Vitis rotundi folia Michx. 

Smilax spp. 

Lonicera japonica 'Ibmh. 

hya candensis var. plsilla Nutt 

Hyperim spp. 

Lespedeza striata Thmb. 

Andromxon l.. scwarius I Michx. 

Cy-perus esculentus L. 

Panicum spp. 

Cassia fasciculata Michx, 

Hypericum gentianoides L. 

Phytolacca americana [~ajm. ] L. 

Adxosia artemisiifolia L. 

3uneus spp. 

-- Rubus trivialis Michx. 

Fragaria virginiana Duchesne 

-- Campsis radicans L. 

i2ummrithium sessilifom Poir . Aristida spp. 

-- Croton capitatus Michx. 

Am* h*rry 

blackgum 

cudjoe 

d 

gallberry 

hickory, bit ternut 

huckleberry 

loblolly pine 

oak , Post 

oak, southern red 

oak, water 

oak, white 

persk 

red mple 

sassafrass 

sumc, smooth 

sumc, staghorn 

sumc, shining 

sweetbay 

swee tgum 

waxrnyrtle 

willow 

yellow poplar 

Caflicarpa wricana L. 

Nyssa sylvatica Marsh. 

Jacquinia keyensis Mez, 

-- canus florida L. 

Ilex glabra L. 

Cvyacordiformis ~och. 

vaccinium spp. 

-- Pinus taeda L. 

Quercus stellata Wag. 

9. falcata Michx. 

4. nigra L. 

q. +& L. 

Diospyros virginiana L. 

-- Acer drum L. 

-- Sassafras albidum Nutt . -- Rhus glabra L. 

-- R, hirta L. 

R, copallina L. 

-&gnolia virginiana L. 

Liquidanbar styraciflua L. 

mica cerifera L. 

-- Salix nigra Marsh 

Liriodendrm tulipifera L. 

The herbaceous component on the plots with no 

contfol ranged from 40 to 95 percent in the 

second year. Due to care in herbicide applications and innovative methods in treating woody 

stems, the herbaceous coverage increased in the 

second year on the woody control treatments at 

most locations. Herbaceous control has been 

successful at most locations, yielding less than 

15 percent cover, except at Jena, LA, Crossett 

AR, and Bainbridge, GA. At the Jena location, 

severe infestations of woolly croton developed 

prior to evaluation. Vine infestations, although 

undergoing control treatments, still remain a 

problem at the Crossett and Bainbridge locations. 

In the second year, woody cover was less than 

I1 percent on all woody and total control plots. 

Woody competition on the no control plots varied 

widely by location, from a low at Warren, AR, of 

less than 2 percent, to three locations with over 

40 percent woody cover. American beautyberry and 

sumacs have required constant control pressure. 

At nine locations, the control of herbaceous competition appears to have released the woody 

cover, as noted by greater cover values on herb 

control compared to no control treatments. 

Pine cover is still low after two growing 

seasons, but a significant response to treatment 

is evident at most locations. The greatest 

amount of pine cover was at Bainbridge and in the 

naturally regenerated stand at Crossett. 

Pine Response 

Pine growth (table 5) at all locations was 

generally, but not consistently, least on the no 

control treatments and greatest with total 

control. In the first year, seedling heights 

were significantly different by treatment at 7 

locations, while groundline diameters were significantly different at 11 locations. None of the 

locations with significant growth differences 

showed any additional growth with woody control 

compared to no control. Thus woody competition 

had not significantly detracted from growth. 

Herbaceous control did however yield significantly increased height growth at 5 locations and 

larger GLD's at 10 locations. 

In the second year, diameters differed significantly between treatments at all locations, while 

height differed significantly at all but four 
Table 4.-Percent ewer of c ts aMf. percent bare ground and loblolly pine cuver after the first ad secd years, by tmtmnt control classes, for 

13 sites in the Seuthern United States 

Vegetation Crmsett Wmen Jena Livepl Liberty Carnce AWre Tallassee Camp Hill Bainbridge mticello Mr&e ttox 

Control BR AR LA LA MS 2N AT., AL AL GA GA GA VA 

Bare ground 

f~, 25.0 b 9,7 c 11.2 c 

data 30.9 b 20.5 c 7.7 c 

93.8 a 55.6 b 83.5 b 

97.0 a 97.3 a 96.1 a 

Herbacews Wer 

no 75.0a 71.4a 67,8b 

data 69.0 a 75.1 a 91.8 a 

5.7 b 23.6 b 2.3 c 

2.1 b 2.0 c 3.0 c 

Bare ground 

1.8 c 0.3 c 2.7 b 4.5 c 7.8 c 

2.5 c 5.0 c 4.9 b 10.8 c 2.7 c 

60.3 b 42.5 b 74.5 a 67.7 h 56.3 

95.5 a 90.1 a 86.5 a 97.4 a 89.5 a 

m 

WOOTJrY 

HERB 

m 

Woody Carer 

16.9 a 44.2 a 7.4 ab 22.7 a 31.1 a 

1.3b 10.8b 1.6bc 1.3b 0.2b 

23.1 a 31.7 a 12.5 a 25.7 a 40.8 a 

0.3 b 0.6 c 0.2 c 0.3 b 0.0 b 

-- Pine Wer 

2.0 2.0 c 4.9 b 2.0 b 2.0 a 

2.0 NS 2.0 c 5.3 b 2.3 b 2.0 c 

2.0 4.7 b 8.2 a 4.3 ab 5.0 b 

2.0 8.5 a 8.4 a 8.1 a 9.0 a 

beans in a col- folld by the sane letter are not significantly different at the 0.05 level as determined by Em-' s nultiple range test. NS=trea&nt effect not 

significant at the 0.05 level as determined by an analysis of variance and Duncan's nultiple range test not applied. 
a 

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dddo 
sites. Of the nine locations with significant 

differences in second year heights, eight of 

these showed no difference between the woody 

control situation and no control. Likewise, D6's 

were not different at 11 locations when comparing 

woody control and no control. Thus herbaceous 

competition has acted similar to total competition in detracting growth. The same trends 

with herbaceous competition, yielding reduced 

growth, were also evident with the second year 

GLD's, but results of the mean separations were 

more variable in groupings. The largest 

seedlings for both the first and second year were 

grown on lower and middle Coastal Plain sites. 

Tipmoth infested seedlings averaged greater 

than 80 percent at eight locations, which 

resulted in few significant differences due to 

treatment. At Warren, AR, all control treatments 

showed increased tipmoth incidence, especially 

the herb and total control treatments. At 

Liberty, MS, herb control treatments also yielded 

the most trees attacked, but total control had 

the least. At Camp Hill, AL, woody control treatments had the most tipmoth incidence, while at 

Appomattox, VA, the total control was significantly greater than the other competition 

situations. 

Fusiform rust infection was greatest in the 

area of normally high incidence--upland sites in 

Alabama and Georgia. Increased infection was 

found mainly with increasing control of the 

herbaceous component. Monticello, GA, had lower 

levels of herbaceous cover on the no control 

treatments (table 41, which may have influenced 

increased rust incidence. 

The overall pine size means for the plantation 

sites are presented in table 6. This shows more 

clearly the trend of improved early growth with 

herbaceous weed control. Seedlings in the first 

Table 6.--Overall diameter and height means for 

planted loblolly pine site? by treatment after 

the first and second years 

Vegetation First Year Second Year 

Control GLD~ Height GLD ~6~ Height 

- inches - feet --inches-- feet 

None 0.28 1.26 0.66 0.56 2.95 

Woody 0.30 1.33 0.83 0.68 3-18 

Herb 0.42 1.44 1.22 1.04 4.05 

Total 0.49 1.49 1.63 1.37 4.34 

'gainbridge, GA, not included due to missing 

diameter data. 

3GLD=groundline 2 diameters. 

D6-diameter at 6 inches above groundline. 

year on the total control treatment were 75 percent larger in GLD's and 18 percent taller when 

compared to %he no control treatments. 

Herbaceous control alone yielded seedlings that 

were 50 percent larger in diameter and 14 percent 

taller, while seedlings on the woody control 

treatments were only slightly larger than the no 

control pines, After the second growing season, 

the size differences were attenuated. Seedlings 

with total control averaged 147 percent larger in 

GLD's, 145 percent larger in D6's, and 47 percent 

taller when compared to those with maximum 

competition. In comparison to the no control 

situation, seedlings on plots where only the 

herbaceous competition was- controlled resulted in 

GLD's that were 85 percent larger compared to 

only 26 percent larger with woody control. Many 

locations had seedlings that were 8 ft tall with 

2-inch GLD" after two growing seasons of total 

control. 

Pine Moisture Stress 

The averages of the moisture stress readings 

are presented in table 7. The relation between 

first-year GILD'S and plant moisture stress can be 

seen in figure 3, GLD's were reduced in a 

nonlinear trend as plant moisture stress 

increased. The selected regression relation is: 

ln(G~D)=0.465 t 2.87 PMS + 1.02 PMS', where GLD 

is in inches and PMS is in neg3tive mewpascals 

of xylem pressure potential (r =0.93), 

In IGLBI = 0.465-b 2.87 PMS + 1.02 PMS' 

ra ~0.93 

Figure 3. --The relation between xylem pressure 

potential taken in September and groundline diameters after the first year. 

I=no control, 2=woody control, 3=herbaceous control and 4=totaL control 

DISCUSSION 

Just how competition affects pine growth is not 

fully known, only that competition influences the 

availability of the essential factors of water, 

nutrients, sunlight, and growing space. When 

pine seedlings are small, both woody and 

herbaceous components compete for all of these 

factors, After about 3 to 4 years, surviving 
Table 7.--Xylem pressure potential of loblolly 

pines taken on September 27 and 28, 1984, during 

the first growing season after 20 days without 

rainfall 

Vegetation 

Control Tallassee Camp Will Overall 1 

negative MPa-------------- 

None 1.10 1 ,37 1.23 a 

Woody 0.83 1.13 0.98 ab 

Herb 0.60 0.90 0.75 bc 

Total 0.46 0.45 0.46 c 

ANOVA Results: Pr>F 

Treatment 0.02 

Block 0.71 

Treatment x Block 0.24 

'overall means followed by the same letter are not 

significantiy different at the 0.05 level as 

determined by Duncan's multiple range test. 

pines will stand above herbaceous competitiors and 

only woody species influence sunlight and aerial 

growing space. Possibly, herbaceous weeds offer 

little pine competition after 7 years (Clason 

1978). Hardwoods can continue to compete for all 

essential factors throughout the rotation since 

they capture both aerial and rooting space. 

On most upland sites it is generally assumed 

that moisture is the most limiting factor when 

pine growth is affected by competition. Nelson 

and others (1981) reported that reduced moisture 

stress as a result of herbaceous weed control was 

associated with increased early loblolly pine 

growth. On sites where moisture was not limiting, 

weed control did not result in increased growth. 

Carter and others (1984) found that both woody and 

herbaceous competition influenced loblolly pine 

moisture stress more than they influenced foliar 

nutritional status. Higher moisture stress levels 

were found on Piedmont soils compared to pines 

growing on Coastal Plain soils, the same as found 

in the current study. In viewing the current data 

growth of loblolly pine seedlings, and stress 

levels of -1.4 MPa induced seedling dormancy 

(Cannell and others 1978). Thus only on the 

lowest competition levels was moisture stress 

reduced to levels where growth occurring before 

daylight was not negatively influenced. More 

information will be reported on nutritionalcompetition interactions since all COMP locations 

sampled foliage after the second growing for 

nutrient analysis in cooperation with the North 

Carolina State Forest Tree Nutrition Cooperative. 

have severe hardwood competition developing. On 

herb control plots, some pines that are completely 

surrounded by taller hardwoods already appear 

retarded. With herb control bdth the pines and 

hardwoods have been equally released and the race 

for canopy position has accelerated, freed of 

herbaceous weed competition. 

The COMP growth values represent biological 

standards for loblolly pine on the specific study 

sites and relative to patterns in precipitation, 

Sizes and growth increments of pine grown completely without competition approach as absolute a 

value as we have in vegetation management 

research. At the opposite end of the scale are 

growth values on plots with no competition 

control. The growth between these extremes 

represents a wide spectrum of possibilities for 

loblolly pine. These growth values may be usable 

as a gauging network to assess relative growth for 

other studies . 

The values for the woody control treatments 

represent the ideal of most operational herbicide 

treatments for site preparation--control of all 

woody competition. The long-term value of this 

current strategy will be evaluated by future COMP 

test results. Woody control plots should also be 

similar to abandoned fields or pastures that have 

been planted or seeded with pines. 

Perhaps the most interesting treatment is herbaceous control that allows site resources to be 

available to only woody vegetation and lets the 

total wood production of both pines and hardwood 

be realized. Hardwood growth will be measured 

more intensively in the coming years to determine 

the range of volume mixtures possible with total 

herbaceous control. 

CONCLUSIONS 

Herbaceous competition detracts more from early 

growth of loblolly pines than does juvenile hardwood competition. Pine diameters were reduced by 

herbaceous competition more often than heights. 

The absence of any competition for 2 years yielded 

pine seedlings that were about 50 percent taller 

and 1.5 times larger in diameter than seedlings 

grown on predominantly chop and burn treated sites 

where there was no additional competition control, 

The predominate herbaceous competitors were 

panicum grasses, bluestems, and asteraceae forbs. 

Fusiform rust in high incidence areas may be 

significantly increased following control of 

herbaceous vegetation. Tipmoth incidence appears 

to be more a function of location than of 

vegetation control treatment. 

LITERATURE CITED 

Bacon, G.G.; Zedaker, S.M. Competition control in 

young loblolly pine plantations of the Virginia 

Piedmont. In: Proceedings, 39th Annual Meeting 

of Southern Weed Science Society; 1985 January 

20-22; Nashville, TN. Champaign, IL: 

Southern Weed Science Society; 1986: 196. 
Cain, M.D.; Mann, W.F., Jr. Annual brush control 

increases early growth of loblolly pine, 

Southern Journal of Applied Forestry. 4: 67-70; 

1980, 

Cannell, M.G.R.; Bridgewater, F.E.; Greenwood, 

M.S. Seedling growth rates, water stress 

response, and root shoot relationships related 

to eight year volumes among families of Pinus 

taeda L. Silvae Geneticia. 27: 237-248; 1978. 

Carter, G.C.; Miller, J,H; Davis, D.E.; Patterson, 

R.H. Effect of vegetative competition on the 

moisture and nutrient status of loblolly pine. 

Canadian Journal of Forest Research. 14: 1-9; 

1984. 

Clason, T.R. Removal of hardwood vegetation 

increases growth and yield of a young loblolly 

pine stand. Southern Journal of Applied 

Forestry. 2: 96-97; 1978. 

Knowe, S.A.; Nelson, L.R.; Gjerstad, D.H.; Zutter, 

B.R.; Glover, G.R.; Minogue, P.J.; Dukes, J.H., 

Jr. Four-year growth and development of planted 

loblolly pine on sites with competition control, 

Southern Journal of Applied Forestry. 9: 11-15; 

1985. 

Nelson, L.R.; Pedersen, R.C.; Autry, L.L.; 

Dudley,S.; Walstad, J.D. Impacts of herbaceous 

weeds in young loblolly pine plantations. 

Southern Journal of Applied Forestry. 5:153; 

1981. 

Tiarks, A.E.; Haywood, J.?. Pinus taeda L. 

response to fertilization, herbaceous plant 

control, and woody plant control. Forest Ecology 

and Management. 14: 103-112; 1986. 

Waring, R.H.; Cleary, B.D. Plant moisture stress: 

evaluation by pressure bomb. Science. 

155: 1248-1254; 1967. 
PIEDMONT BOTTOMLAND HARDWOOD REA;ENERATION RESP0NZ)S TO 

PREHARVEST JAPANESE HONEYSUCKLE CONTROL" 

E.J. Schmeckpeper, R. Lea, D. Phillips, and L. Jervis. 

2 

ABSTRACT.-- Preharvest herbicide treatment with Glyphosate of Japanese 

honeysuckle (bnicera japonica) was followed by clearcut harvesting and 

chainsaw felling of residual stems. Treated plots had significantly 

less area covered by honeysuckle than control plots in which no 

herbicides were applied. Hardwood regeneration on the treated plots 

was primarily of seedling origin compared to predominantly sprout 

origin on the controls. Treated areas had significantly more free-togrow stems of desirable species, fewer stems of undesirable species, 

and less honeysuckle competition than the control areas. Initial oak 

advanced regeneration was adversely affected by the preharvest 

herbicide treatment. Oak regeneration also appeared to be affected by 

the herbicide treatment although this was not significant, 

Keywords: Clearcutting, Competition, Weeds, Herbicides. 

INTRODUCTION 

There are more than 28 million acres of land 

classified as commercial forest land in the 

Piedmont of which approximately 17 million acres 

are in hardwood forest types. Within the hardwood 

type over 1.9 million acres are classified as 

Piedmont bottomland hardwood forests (Bechtold and 

Phillips 1983). 

Most of the valuable hardwood species found on 

bottomland site types are intolerant to moderately 

tolerant of shade (Putnam gt 21. 19601, and are 

best managed with an even-aged system. Clearcutting with residual control of culls, low 

quality trees, and undesirable species is 

recommended for regenerating these sites (Bowling 

and Kellison 1983; Kellison e& al. 1981; Loftis 

1980; McGee 1982; McGee and Hooper 1970; Zobel and 

Davey 1975). However, clearcutting has not been 

completely successful on Piedmont bottomlands, 

primarily because of competition from woody and 

herbaceous vines (Kellison 1977; Bruner 1967). 

The weed species of pri~ary concern in Piedmont 

bot tontlands is Japanese honeysuckle ( Lonicefa 

japonica), a climbing, semi-evergreen woody liana. 

--------------- 

I Paper presented at the Fourth Biennial 

Silvicultural Research Conference, Atlanta, GA., 

November 4-6, 1986. Paper No. 10827 of the 

Journal Series of the North Carolina Agric. Res. 

Serv., Raleigh, NC 27695. 

Research Assistant, North Carolina State 

University, Raleigh, NC. 27695-8002; Associate 

Professor of Forestry and Soil Science, North 

Carolina State University, Raleigh, NC.; Project 

Leader, Southeastern Forest Experiment Station, 

Forest Service, U.S. Department of Agriculture, 

Clemson, SC.; Associate Professor of Forestry, 

North Carolina State University, Raleigh, NC. 

Although Japanese honeysuckle is deciduous in 

the Northeast, it is an evergreen plant in the 

Piedmont. It produces large quantities of seed 

which are disseminated by birds and animals 

(Leatherman 19551, and dispersed by floodwaters 

(Brender 1960). Once established, honeysuckle 

spreads by layering and can rapidly dominate 

openings in the forest canopy. Honeysuckle is 

present throughout the Piedmont and grows well on 

many soil types (Craver 1982; Leatherman 1955). 

Honeysuckle stem elongation begins before 

deciduous tree seedlings undergo budbreak. While 

kept in check by a closed canopy, honeysuckle 

takes advantage of openings and rapidly forms 

dense mats. These mats may smother shrubs, tree 

seedlings and saplings, and may inhibit the 

establishment of a new crop of trees (Brender 

1961). 

Studies with Japanese honeysuckle indicate that 

it grows relatively poorly in terms of bionass at 

very low light intensities (i.e., 5 to 10% of full 

sunlight) (Leatherman 1955; Blair 1982). However, 

maximum shoot growth occurs at 10 to 25% of full 

sunlight (Leathernlan 1955; Schmeckpeper 1986). 

Thus, crown openings large enough to permit 

adequate hardwood regeneration dre also large 

enough to allow significant honeysuckle growth and 

subsequent intense competition. 

Clearcutting in ccmbination with a preharvest 

herbicide treatment has denionstrated potential for 

reducing competition from undesirable species on 

Piedmont bottomland sites. This study evaluates 

the effects of preharvest herbicide treatments 

with Glyphosate3, in combination with 

clearcutting, on Japanese honeysuckle competition 

and natural hardwood regeneration. ---------------- 

The use of tradenames is for the convenience of 

the reader and does not constitute an official 

endorsement or censure. 
/ 

PROCEDURES RESULTS AND DISCUSSION 

diudy Area #- 

This study was located on the North Carolina 

State University Hill Demonstration Forest in 

Durham County, North Carolina. It occurs in a 

natural hardwood site on a narrow floodplain along 

Dial Creek. This site was chosen to test the 

effects of a preharvest application of the 

herbicide Glyphosate on competing understory 

vegetation consisting primarily of Japanese 

honeysuckle. 

The six acre study area was divided into three 

blocks approximately 2-acres in size. Each block 

was divided in half, perpendicular to Dial Creek, 

One half of each block received the herbicide 

treatment, and the other half maintained as a 

control. 

Treatments 

In the treated portions of each block, a foliar 

spray of 1.5% Glyphosate solution was applied with 

a backpack sprayer to all understory vegetation at 

a rate of 12 gal/ac during mid-July 1982. In 

August 1983, areas with Japanese honeysuckle that 

were missed by the first application received a 

follow-up spraying with a similar solution to that 

used in 1982. Prior to the follow-up spraying, 

the advanced reproduction, stems shorter than 4.5 

ft, was inventoried in the entire study area and 

percent ground cover cf Japanese honeysuckle was 

estimated ocularly. 

The 6-acre stand was harvested in the winter of 

1983-1984 using chainsaws. Residuals greater than 

2 inches DBH were chainsaw-felled following the 

harvest. Regeneration and competing vegetation 

were inventoried at the end of the two growing 

seasons followi.ng the h- arvest. 

Data Collection 

The regeneration inventory included the 

inventory of the following paranieters: 

1) tree species. 

2) stem origin (seedling or sprout). 

3) presence and type of competing vegetation 

(e.g. honeysuckle, other liana species, 

grasses, sedges, etc.), 

4) percent of the sample plot area covered by 

liana vegetation (determined ocularly and 

rechecked with a dotgrid), 

5) height of the liana competition, 

6) number of tree stems potentially suppressed 

by liana competition, 

7) ability of the dominant stem of each sprout 

cluster or each seedling to grow freely, 

To assess the biomass accumulation of each 

treatment a one-meter square plot was randonly 

placed near each sample plot. On these plots, all 

non-tree vegetation was clipped, separated into 

liana and non-liana classes, and oven-dried. 

Preharvest Stand Characteristics 

Prior to harvest, the Dial Creek bottomland 

stand was con~posed ~rimarily of: yellowpoplar (~iriodendron tulipif era), sweetgum 

(Liquidambar styraciflua), oaks (Quercus spp.), 

sycamore (Platanus occidentalis), and ash 

(Fraxinus spp.). Scattered shortleaf (Pinus 

echinata) and loblolly ( P. taeda) pines were 

also present. 

One year after the initial herbicide application 

and prior to harvest, honeysuckle control appeared 

to be effective. Ground cover of the noxious weed 

was reduced to an alrerage of 6% from approximately 

40%. However, advanced reproduction of some 

desirable species was adversely affected by the 

herbicide. 

The advanced reproduction and sapling inventory 

conducted prior to the follow-up herbicide 

application indicated that an average of 1180 

stems per acre of desirable species less than 4.5 

feet tall were in the control plots, and only 250 

desirable stems per acre were in the herbicide 

treated plots (Table 1). The reduction in oak and 

hickory (Carya spp.) reproduction showed these 

species to be especially susceptible to the 

herbicide. Other species present on the control 

plots, sweetguxr., yellow-poplar, ash, and blackgum 

(Nyssa spp.), either did not occur or were killed 

on the treated plot. The susceptibility of oak 

and hickory to Glyphosate has been shown by other 

researchers (Moran 1984). 

Table 1.- Preharvest inventory of advanced 

reproduction on Dial Creek (height < 4.5 feet) 

one growing season after preharvest competition 

control treatment with Glyphosate herbicide. 

Treatment 

Species Control Treated - 

(stems per - acre) 

Oaks 367 84" 

Sweet gum 88 0 

Yellow-poplar 13 0 

Ash 129 0 

Hickories 500 166" 

Total 

Desirables 1263 250" 

Other species1 4800 12 10" 

Includes ironwood, dogwood, and non-commercial 

hardwood species. * Indicates a significant difference between 

treatment and control at the 0.05 probability 

level. 

Effect of Herbicide Treatment on Competition 

Two years after the Dial Creek stand was 

harvested, the herbicide treatment continued to 

exert control on honeysuckle competition. The 

area covered by Japanese honeysuckle and other 

liana competition was significantly less on 

treated plots than on the controls (Table 2). 
Table 2.- Average percent ground cover by 

Japanese honeysuckle in a naturally regenerated 

Piedmont bottomland hardwood stand at one and 

two growing seasons following clearcutting. 

Percent Ground Area Covered 

Year Control 

1 41.9 

Treated 

20.4* 

* Indicates a significant difference between 

treatments at the 0.05 level. 

Total biomass of all competing vegetation, both 

liana and nonliana, was approximately equal 

between treatments (Table 3). Space created by 

removing honeysuckle was filled by other plants, 

especially annuals. 

Table 3.- Biomass of lianas and other competing 

vegetation on a naturally regenerated Piedmont 

bottomland hardwood stand the second growing 

season following clearcutting. 

Tons per Acre 

Vegetation control Treated 

Honeysuckle & 1.41 0.92 

other lianas 

Nonliana s 0.54 0,98* 

Total 1.95 1.90 

* Indicates a significant difference between 

control and treatment class at the 0.05 level. 

By the end of the second growing season, 

honeysuckle was found in the same proportions in 

both the treated and control plots (Table 4). 

However, treated plots had more annuals, grasses, 

and sedges than the control plots. Although the 

biomass of Japanese honeysuckle was significantly 

affected by the herbicide treatment, it was not 

eradicated by this treatment. Honeysuckle was 

present on nearly all plots in the treated areas. 

The implications are that honeysuckle has the 

potential to reclaim large portions of the site. 

Table 4.- Percent of plots with Japanese 

honeysuckle and other weed species present on a 

naturally regenerated Piedmont bottomland 

hardwood stand for the two growing seasons 

following clearcutting (No significant 

differences were found between treatments within 

years at the 0.05 probability level). 

Presence of Vegetation 

Control Treated 

Species Class Year 1 Year 2 Year 1 Year 2 ----------- Percent------------ 

No Competition 0 2 13 0 

Honeysuckle 94 96 7 8 96 

Annuals* 9 2 1 5 4 4 

Blackberry 14 19 2 2 1 

* Includes grasses, sedges, and other annual 

herbaceous vegetation. 

Regenerat ion Measurements 

Two growing seasons following the commercial 

harvest and residual removal, in the winter of 

1983 - 1984 an average of 3540 stems/ac was found 

on the control plots and 5210 stemslac on the 

treated plots (Table 5), Treated plots had 

significantly more and higher proportions of 

seedlings per acre than the control plots. 

Table 5 .- Comparison of seedling and sprout 

regeneration (number of stems per acre) of a 

naturally regenerated Piedmont bottomland 

hardwood stand for two growing seasons 

following clearcutting. 

Treatment 

Control Treated 

Origin Year 1 Year 2 Year 1 Year 2 -------- (stems per acre)--------- 

Seedlings 4360 1430 8510* 3860" 

Sprouts 3140 2110 1010* 1350 

Total 7500 3540 9520" 5210 

* Indicates a significant difference between 

treatments within years at the 0.05 probability 

level. 

In both the first and the second growing seasons 

following harvest, the control plots had more 

tolerant undesirable species which sprouted 

vigorously after harvest (e.g. ironwood (carpinus 

caroliniana) , dogwood ( cornus f lorida) , and 

sourwood (Oxvdendrum arboreurn)) . than the herbicide . 

treated plots (Table 6). Conversely, many 

sapling-sized dogwood and ironwood trees were 

killed by the preharvest herbicide treatment and 

did not resprout after the harvest. Loftis (1985) 

reported similar reductions in numbers of stems of 

undesirable species following preharvest herbicide 

treatments. 

Table 6.- Comparison of seedling and sprout 

regeneration of desirable and undesirable tree 

species of a naturally regenerated Piedmont 

bottomland hardwood stand for two growing 

seasons following clearcutting. 

Treatment 

Control Treated 

Origin Year I Year 2 Year 1 Year 2 -------- (stems per acre)------- 

Desirables 

Seedlings 3440 1250 7800" 3770% 

Sprouts 850 630 450 490 

Undesirables 3210 1660 1270% 950 

* Indicates a significant difference between 

treatments and within years at the 0.05 

probability level. 

Sprouts also made up a higher proportion of the 

desirable stems in control plots. At the end of 

the second growing season, oaly 11.4% of the 

desirable stems in the treated plots were sprouts. 

In contrast, sprouts composed 33.72 of the 

desirable stems on the control plots. 
Effects of the preharvest herbicide treatment on 

species composition are reflected by the 

distribution of desirable species (Table 7). In 

the control plots, oaks comprised 11.2% of the 

desirables in year one and 8.9% in year two. 

However, oaks were negligible on the treated 

plots. Species which regenerate prolifically by 

seed, such as yellow-poplar were present in 

greater proportions on the treated plots. 

Table 7,- Distribution of regeneration of 

desirable tree species of a naturally 

regenerated Piedmont bottomland hardwood stand 

for two growing seasons following clearcutting. 

Species 

Desirables: 

Yellow-poplar 

Sweetgum 

Sycamore 

Ash 

White Oaks 

Red Oaks 

Hickory 

Blackgum 

Other Desirables 1 

Treatment 

Control Treated 

---- Year 1 Year 2 Year 1 Year 2 ---------- (percent)----------- 

Includes shortleaf and loblolly pines and other 

desirable hardwood species. 

With less Japanese honeysuckle on the treated 

areas there were fewer suppressed stems. At year 

2, 83% of all stems on the control plots were 

classified as suppressed, compared to 50% on the 

treated plots (Table 8). In the control, an 

average of less than 600 free-to-grow stems per 

acre of desirable species were found; in treated 

areas an average of 2570 free-to-grow desirables 

per acre was found. Although trees may grow 

through honeysuckle mats after several years 

(Hurst and Bourland 1980), the effects of the 

competition on stem quality and the numbers of 

merchantable stems at rotation's end is not known. 

However, even with 590 stems per acre on the 

control areas, it appears that the stand will be 

fully stocked at the end of the rotation. 

Table 8.- Comparison of total free-to-grow 

(F.T.G.) regeneration and free-to-grow 

regeneration of desirable tree species on a 

naturally regenerated Piedmont bottomland 

hard~ood stand for two growing seasons following 

clearcut t ing . 

Total F.T.G. F.T.G. Desirable 

Year Control Treated Control Treated ---------- (stems per acre)---------- 

1 2900 7850" 2347 6840" 

2 1240 3020" 590 2570" 

* Indicates a significant difference between 

treatments and kithin a vegetation class at the 

0.05 probability level. 

In this stand, injection of the undesirable 

residuals might have been a better treatnent than 

clear-felling, Injection of residuals nay reduce 

vine problems by reduciilg siash arid logzing debris 

which honeysuckle uses as a platfora (Hurst and 

Bourland 1980). 

Another alternative to this treatment for 

competition control is a herbicide treats~ent in 

the autumn, after overstory leaf fall. Little and 

Somes (1968) reported good honeysuckle control one 

year after an October spraying. Although sone 

mortality of advanced hardwood regenerat ion was 

reported, the authors speculated that less 

hardwood damage would have occurred with the same 

degree of honeysuckle control if the spraying had 

been delayed until leaves of the overstory trees 

had fallen. 

SUMY AND R ECGMMENDATIGNS 

Preharvest application of Glyphosate produced 

desirable results in Piedmont bottomland hardwood 

stand examined in North Carolina. Significantly 

greater numbers of unsuppressed stems were found 

in areas which received the herbicide treatment. 

The higher proportion of desirable stems on the 

treated plots could produce a more valuable stand 

at the end of the rotation. 

Many Piedmont bottomland stands have been 

high-graded and, as a result, have 

large numbers of culls and undesirable species. 

Preharvest herbicide treatments may be useful in 

rehabilitating these sites by reducing 

regeneration of undesirable species. 

Although the preharvest Glyphosate treatment was 

effective in reducing honeysuckle competition and 

cover, some detrimental side effects occurred. 

Oak advanced reproduct ion was adversely affected 

by the herbicide which could result in fewer oaks 

in the ensuing stand. Alternative treatnents to 

avoid impacts on desired species include spraying 

after leaf fall or injecting rather than chainsaw 

felling residuals. Research is needed to 

determine if oak regeneration is permanently 

affected, and if such a loss outweighs the 

benefits of the herbicide treatments. 

On sites with understories relatively free of 

Japanese honeysuckle, small clearcuts with 

residual control will most likely be sufficient 

for regeneration. Clearcuts smaller than 0.5 

acres nay not be large enough to allow sufficient 

sunlight for regeneration of shade intolerant 

desirable species. However, failure to control 

honeysuckle before harvesting may result in fewer 

free-to-gro~~ desirable seedlings and sprouts. 

Tlzis research suggests that the long-term effects 

of Japanese honeysuckle competition on hardwood 

regeneration, species composition, and timber 

quality of the subsequent stand need further 

tracking in light of its significar't impacts on 

early stand establishaent. 
This study covers only the first two years of a 

dynamic systeEi* Changes in species composition 

and dominance k4LL continue as the stand develops, 

Further study uf long-term herbicide treatment 

effects on honeysuckle competition and stand 

development is needed to determine If honeysuckle 

damage is sufficient to warrant suck treatments. 

Funding for this study was provided by the U.S, 

Dep. Agric. For. Serv., Southeastern Forest 

Experiment Station, Asheville, NC 28804. 

LITERATURE CITED 

Bechtold, W.A.; D,R. Phillips. 

1983. The hardwood resource on nonindustrial 

private forest lands in the Southeast 

Piedmont. U.S. Department of Agriculture 

Forest Service Res. Pap. SE-236. 19p. 

Blair, R.M. 

1982. Growth and nonstructural carbohydrate 

content sf southern browse species as 

influenced by light intensity. J. Range 

Management 36 : 756-760. 

Bowling, D-R . ; R .C. Kellison. 

1983. Bottomland hardwood stand development 

following clearcutting. South. J. AppL. For. 

7:llO-116, 

Brender, E.V, 

1960. Progress report on control of honeysuckle 

and kudzu. Proc. S. Weed Conference 

13:187-192. 

Brender. E.V, 

1961. Control of honeysuckle and kudzu. U.S. 

Department of Agriculture Forest Service 

Station Paper SE-20, 9p. 

Bruner, M.R. 

1967. Honeysuckle - a bold competitor on 

bottomland hardwood sites. For. Farmer 8:9,17. 

Craver, G,C. 

1982. Multiresource inventories - a technique 

for determining the distribution and extent of 

honeysuckle on commercial forest land in South 

Carolina. U,S, Department of Agriculture 

Forest Service Res. Note SE-317, Ilp. 

qurst, G*A. and T-R, Bourland. 

1980. Hardwood decsity and species composition 

in bottomland areas treated for regeneration. 

South. J. Appl. For. 4(3):59-63, 

Kellison, R.C., D.J. Frederick, and W.E. Gardner. 

1981. A guide for regeneration and managing 

natural stands of southern hardwoods. North 

Carolina Agr. Exp. Stn, Bull. 463. 24p. 

Leathernan, A. D. 

1955. Ecological life-history of Lonicera 

japonica Thunb. Diss. Abstr. 15(11):1987. 

Little, S. and H.A. Somes, 

1968. Herbicide treatments of Japanese 

honeysuckle for releasing desirable 

reproduction or for site preparation. k.S. 

Department of Agriculture Forest Service NE 

Exp. Stn. Res. Note NE-83. 8p. 

Loftis, D.L. 

1980. Natural stands: harvesting systems. 

Hardwood Management Short Course. School of 

Forest Resources, NCSC. July 1980, p. 6-13. 

Loftis, D.L. 

1985. Preharvest herbicide treatment improves 

regeneration in Southern Appalachian 

hardwoods. South. J. Appl. For. 9(3):177-180. 

McGee, C.E. 

1982. Low quality hardwood stands. U.S. 

Department of Agriculture Forest Service Gen. 

Tech. Rep. SO-40. 22p. 

McGee, C.E. and R,M. Hooper. 

1970. Regeneration after clear-cutting in the 

Southern Appalachians. U.S. Department of 

Agriculture Forest Service Res. Pap. SE-70. 

12p. 

Moran, J.F. 

1980. Regeneration of bottomland hardwoods 

following a seed tree cut and site 

preparation. Stephen F. Austin State 

University. Nacagdoces, TX: M.S.F. Thesis. 

103p. 

Putnam, J.A., G.M. Furnival, and J.S. McKnight. 

1960. Management and inventory of southern 

hardwoods. U.S. Department of Agriculture Agr. 

Hbk. 181. 102p. 

Schmeckpeper, E.J. 

1986. Competing effects of japanese honeysuckle 

(Lonicera japonica) on natural hardwood 

regeneration in Piedmont bottomland hardwoods. 

N. C. State University. Raleigh, NC: M.S. 

Thesis. 38p. 

Zobel, B.J. and C.B. Davey. 

1975. A simplified guide to hardwood management 

in the Southeast. School of Forest Resources. 

N. C. State University. Raleigh, NC 21p. 

Kellison, R .C. 

197' Changing philosophies in hardwood 

management, & Proc. 2nd Symg, on Southeastern 

Hardwoods. U.Se Department of Agriculture 

Forest Service SE Area, State and Priv, For, 

Dothan, Ala. p. 107-113. 
INDEX OF AUTHORS 

Page Page 

Abercrombie, James A,, Jr. 162 

Anderson, R. L. 538 

Anderson, Walter C. 274 

Applegate, A. R. 58 1 

Atkins, R, Lee 58 1 

Augspurger , M, K. 89 

Ayers, 6. Daniel 5 76 

Baker, James B. 

Barden, Charles J. 

Barnett, James P, 

Beck, Donald E, 

Belanger, R. P. 

Berry, Charles R. 

Bilan, M. Victor 

Blount, Thomas E, 

Bolton, R. K. 

Bonner, F. T. 

Borders, Bruce E. 

Bottenfield, Timothy R, 

Bowl i ng , Doug 

Boyer, James N. 

Boyer, William D. 

Brissette, John C. 

Buckner , Edward 

Buford, Marilyn A. 

Burger, J. A. 

Burger, James A. 

Cain, Michael 

Cain, Michael D. 

Campbell , Sam 

Cao, Quang V. 

Carlson, William C. 

Caulfield, Jon P. 

Chambers, J. L. 

Clark, A,, 111 

Clason, Terry R, 

Cl ifton, R.G.P. 

Cook, James E. 

Cox, S. K. 

Daly, Edward 

DeAngelis, J, D, 

Dicke, S. G, 

Dicke, Stephen G. 

Dippon, Duane R. 

Duffy, P. D. 

Dwyer, Stephen P. 

Edwards, M, Boyd 

Eriksson, M. 

Evans, Richard 

Farrar, Robert M,, Jr. 343, 508, 527 

Feret, P. P. 24 5 

Feret, Peter P. 230, 237 

Francis, John K. 120 

Frederick, D, J, 147, 466 

Freyman, Robert C. 230 

Glover, G, R. 

Golden, Michael S. 

Gottschal k, Kurt W. 

Graney, D. L. 

Granskog, James E. 

Greene, W, Dale 

Gresham, C, A. 

Gresham, Charles A. 

Guldin, James M, 

Guldin, Richard W. 

Guynn, D. C. 

Guynn, David C., Jr. 

Hafley, W. L. 

Harri ngton, Constance A. 

Harrison, W. Michael 

Hassan, Mohammad 

Hatchell, G. E. 

Hatchell, Glyndon E. 

Haugen, D. A. 

Hay, R. L. 

Haywood, James D. 

Hedden, Roy L. 

Hi ckman, Cl i f ford A. 

Hockman, Joseph N. 

Hodges, J. D. 

Hodges, John D. 

Hollis, Charles 

Honea, C. R. 

Hurst, G. A. 

Ince, Peter J. 

Isaacson, Christopher V. 

Janzen, G. C. 

Janzen, Greg 

Jervis, L. 

Johansen, R. W. 

Johnsen, K. H. 

Jones, Earle P., Jr. 

Kais, Albert G. 

Knight, Herbert A. 

Knowe, Steven A, 

Kormanik, P. P, 

Kreh, Richard E. 

Kroll , James C. 

Kul havy, David L. 

Kush, John S. 

Lanford, Bobby L. 

Lea, R. 

Leduc, Daniel J, 

Lenhart, J. David 

Lloyd, F. Thomas 
Page Page 

Matney, Thomas G. 

McKee, W, H. 

McKee, William H., Jr. 

McLemore, 6. F. 

McMi nn, James W. 

McNab, W. Henry 

McNeel , Joe 

Meeker, James R. 

Megalos, M. A. 

Meldahl, R. S. 

Meldahl , Ralph S. 

Mengak, Michael T. 

Miller, Ansel E. 

Miller, James H. 

Mu1 1 i ns , John 

Murphy, Paul A. 

Nance , Warren L. 

Nebeker, T. E. 

Needham, T. D. 

Needham, Ted 

Newcomer, Keith P. 

Mix, L. E. 

Nodine, Stephen K. 

Nusser, Sarah M. 

Outcalt, Kenneth W. 

Paganel 1 i , David J. 

Paschke, Jeff 

Pesonen, Kari 

Phillips, D. 

Phillips, D. R. 

Phi 11 ips, Douglas R. 

Pienaar, L. V. 

Pope, P. E. 

Pope, Phil E. 

Prenger, R. S. 

Rennie, J. C. 

Retzlaff, Wi 11 iam A. 

Ri ekerk , Hans 

Roeder, Kenneth R. 

Ruehle, J. L. 

Sanders, D, L, 

Schmeckpeper, E. 3, 

Schmidtling, R, C, 

Seifert, John R. 

Seiler, 3. R, 

Sharik, Terry L. 

Shearin, A, f. 

Shearin, Arthur T, 

Shoulders , Eugene 

Siegel, William C. 

Simmons, G. L. 

Si rois, D. L. 

Smith, David Wm. 

Smith, M. W. 

Smith, W. D. 

Smith, William D. 

Souter, Ray A. 

South, David B. 

Stafford, C. W. 

Stokes, B. J, 

Stuhl inger, H. C, 

Sullivan, Alfred D, 

Sutton, W.R.J. 

Terry, Donna N. 

Thor, Eyv-ind 

Ti arks, A1 tan E. 

Toler, Joe E. 

To1 iver, J. R. 

To1 iver, John R. 

Torbert, 3. L. 

Torreano, S. 3, 

Tufts, R. A, 

Ursic, S. J. 

Van Lear, D. H. 

Van Lear, David H. 

Wade, D. D, 

Wade, Dale D, 

Waldrop, Thomas A. 

Watterston, Kenneth G, 

Weise, D. R. 

Wentworth, Thomas R. 

Wi 1 der-Ayers , Jean A, 

Xydias, G. Kenneth 

Zedaker, Shepard M, 

Zeide, Boris 

Zutter, Bruce 

Zweede, J. 

*U, S, GOVERNttKlkT PRINTING OFFICE:1987-732-781