Current Topics in Forest Research: 

Emphasis on Contributions by Women Scientists 

Proceedings of a National Symposium 

Gainesville, Florida 

November 4-6, 1986 

Compiled by 

Susan V. Kossuth 

and 

Nancy A. Pywell 

Sponsored by 

USDA Forest Service, Southeastern Forest Experiment Station 

University of Florida, School of Forest Resources and Conservation, 

Department of Forestry 

Published by 

Southeastern Forest Experiment Station 

Asheville, North Carolina 

1987 

PREFACE 

The concept and objectives of this symposium 

were not new, only the cosponsors. The first 

symposium emphasizing contributions from women 

scientists was held in 1983. The increasing number 

of women in natural resources and the USDA Forest 

Service's comitment to promote, enhance, and 

endorse civil rights suggested that the timing was 

right for a second symposium to bring together 

women in natural resources research to present 

their research findings. This time the format was 

changed. An opportunity was presented to women and 

men to contribute oral or poster papers as well as 

to hear presentations from invited speakers. 

To announce the symposium, information was 

sent to many professional journals in an effort to 

reach researchers in universities, government 

agencies, and forest industry. This was undertaken 

by the Program Committee, consisting of: 

Susan V. Kossuth 

Principal Plant Physiologist 

Southeastern Forest Experiment Station 

University of Florida, Gainesville 

Nancy A. Pywell 

Assistant Professor of Forestry 

School of Forest Resources 

and Conservation 

University of Florida, Gainesville 

Sharon G. Haines 

Section Leader, Soils Research 

International Paper Company 

Bainbridge, Georgia 

We have many individuals and organizations to 

thank for the success of the symposium. First, 

special thanks to Jerry A. Sesco, Director, Southeastern Station, for creating the opportunity for 

the symposium, for his quiet behind-the-scenes 

support and encouragement, for financial backing, 

and for serving as a buffer against critics by 

responding to their comments without bogging down 

the Program Committee. Thanks go to Arnett C. 

Mace and C.P. Pat Reid, University of Florida, 

School of Forest Resources and Conservation 

(SFRC), for their full endorsement in cosponsorship of the symposium. Thanks to Thomas F. Geary, 

USDA Forest Service, International Forestry, who 

was instrumental in announcing the symposium 

worldwide, resulting in the attendance of several 

women from foreign countries. A special thanks to 

Max Peterson, Chief of the Forest Service, for his 

positive comments in the Keynote Address. We wish 

to acknowledge the meticulous work of Monica 

Lindberg, University of Florida, SFRC, who handled 

registration and financial arrangements. Appreciation is extended to Jefferson-Smurfit Company for 

the afternoon tour "Southern Forestry in Action." 

Thanks also to many unnamed people in civil 

rights, personnel offices, and administrative 

positions in universities, government, and 

industry who supported the symposium by encouraging and supporting participants from their 

respective organizations. Finally, we wish to 

thank the speakers and participants who came and 

fulfilled beyond all expectations the objectives 

of the symposium as outlined in the opening 

Overview. 

Papers published in this proceedings are as 

they were submitted by the authors--in cameraready form. Authors are responsible for the 

content and accuracy of their papers. Statements 

by contributors outside the USDA Forest Service 

may not necessarily reflect Department policy. 

SUSAN V. KOSSUTH 

NANCY A. PYWELL 

iii 
CONTENTS 

Preface 

Overview. .............................................. 1 

Susan V. Kossuth 

Keynote Address: Women in Natural Resources ............................. 2 

R. Max Peterson (Invited paper) 

Use of Models in Resource Management ............................... 6 

Katherine C. Ewe1 (Invited Paper) 

Advances in Modeling Silvicultural Treatments in Loblolly Pine Stands ............... 10 

Marilyn A. Buford (Invited Paper) 

Ecophysiological Diversity of Ectomycorrhizae ........................... 14 

Carolyn S. Bledsoe (~nvited paper) 

Stand Dynamics and Early Growth of Yellow Birch and Associates in the White Mountains ....... 20 

Deborah B. Hill 

Effects of Mexico's Selective Cutting System on Pine Regeneration and Growth in 

in a Mixed Pine-Oak (Pinus-Quercus) Forest ............................ 27 

Laura C. Snook and Patricia Negreros C. 

GENETICS 

Gains from Superior Tree Selection in Black Spruce and White Spruce ................ 32 

Katherine K. Carter (Invited Paper) 

Geographic Variation of Allozymes in Eastern Larch (Larix laricina (~uRoi) K. Koch) 

from Northwestern Ontario ..................................... 35 

Peggy H. Knowles and Dan J. Perry 

SOILS AND NUTRIENTS 

Soil and Foliage Analysis in Intensive Forest Management ..................... 40 

Sharon G. Haines and L. Wayne Haines (Invited Paper) 

Tropical Forests and the Global Carbon Cycle ........................... 49 

Sandra L. Brown (Invited Paper) 

Xylem Sap Technology: A New Frontier in Forestry Research .................... 55 

Nellie M. Stark (Invited Paper) 

Calcium and Phosphorous Content of Oak Ectomycorrhizae from Mull and Mor Forests 

of Northeastern Pennsylvania ................................... 60 

Lorraine Mineo, J. L. Wasserman, S. K. Majumdar, C. VanTyne and R. Zelnick 

Soil Physical and Chemical Properties Associated with Three Site Preparation 

Techniques and their Effects on Growth and Survival of Seedlings in Northern Idaho ........ 66 

Deborah Page-Dumroese, Martin F. Jurgensen, R. T. Graham and Alan E. Harvey 

The Use of Senescent Cultures of Postia placenta, Gloeophyllum saepiarium, and 

Gloeophyllum trabeum in the Study of Wood Decay .......................... 71 

Jessie A. Micales and T. L. Highley 

REGENERATION 

A Consideration of Factors Affecting the Development and Physiology of 

Tissue-cultured Plants ...................................... 82 

Hazel Y. Wetzstein (Invited paper) 

An Exceptional Case of Natural Regeneration of White Spruce in Interior Alaska .......... 86 

Tricia L. Wurtz and John C. Zasada 
FCIRF,SI' PRODUCTS 

A System Approach to Structural Design of Roof Assemblies ..................... 89 

Monica McCarthy and Ronald Wolfe 

Strength of Mechanically Fastened Wood Connections ........................ 92 

Marcia Patton-Mallory 

Modeling the Effect of Moisture Content on the Flexural Properties of Dimension Lumber ...... 96 

Carol L. Link 

SOCIOLOGY 

The Importance of Archeological Sites Related to the Naval Stores Industry in Florida ...... .lo5 

Sandra Jo Forney 

Community Forestry in Mexico's Natural Forests: The Case of San Pablo Macuiltianguis ...... ,108 

Laura C. Snook 

Diffusion of Innovations: A Sociological Approach to the Nonindustrial Private 

ForestsChallenge ......................................... 115 

Jacqueline L. Haymond 

ECONOMICS 

A Comparison of Profitability for Agricultural and Forestry Production on Southern 

Marginalcropland ......................................... 120 

Aurelia B. Harris 

Determinants of Hardwood Lumber Price .............................. .I27 

Jennifer M. Jacobsen and William G. Luppold 

An Economic and Ecological Perspective on the Renewability of Forest Ecosystems ......... .131 

Judith Maxwell 

POLICY 

Forestry Research Evaluation: Why and How ........................... .I37 

Pamela J. Jakes and David N. Bengston 

Technology Transfer: A Case Study of Diversity ......................... .I41 

C. Denise Ingram, Jan G. Laarman, and Michel C. Contezac 

State Forest Practice Regulation--the Massachusetts and California Cases ............ .I44 

Terry K. Haines and William C. Siege1 

INSECTS AND DISUSE 

A Cone and Seed Disease of Southern Pines Caused by the Pitch Canker Fungus ........... .I50 

Jane Barrows-Broaddus (Invited Paper) 

Insect Research in Great Plains Windbreaks ........................... .I55 

Mary Ellen Dix (~nvited Paper) 

Hormonal Regulation of Mycorrhiza ................................ .I63 

Nada Gogala 

ELISA Applied to Forest Pathology ................................ .I68 

Pauline C. Spaine 

The Biology of Leucolopsis pulverulenta Dognin (Lepidoptera, Geometridae) ............ .I74 

Joy Woolfson de Noboa 

Soil Solar Heating for Pest Control at Colorado and Nebraska Forest Tree Nurseries ....... .I77 

Diane M. Hildebrand 

Managing Insects Affecting Oak Regeneration by Prescribed Burning ................ .I86 

Susan L. Wright 

Registrants ............................................ .I93 

OVERVIEW 

Susan V. Kossuth 

The first symposium of this kind grew out of 

the creative thinking of scientists at the USDA 

Forest Service, Northeastern Station, and developed with strong support from the enlightened 

management of their Director, Denver Burns. 

Margaret M. Harris of the Northeastern Station and 

Ann M. Spearing of the University of Vermont at 

Burlington made the concepts and ideas of the 

symposium a reality to me and many others in 

attendance at that first meeting on September 16- 

17, 1983. This second symposium originated in an 

informal discussion I had with Jerry Sesco, 

Director of the USDA Forest Service, Southeastern 

Station, He was concerned that I not feel alone 

and isolated as the only woman Project Leader and 

scientist in the Forest Service in Florida. We 

discussed opportunities for contact with other 

women scientists. I commented on the symposium 

held at Burlington in 1983 because there I made 

new friends and learned about companionship of 

women in research that is different from companionship of women with men in research. In the 

months after the first symposium I changed my 

whole concept of "women in forestry." The timing 

was right and the opportunity was created. 

Many women, like me in 1983, do not even 

recognize that they need meetings such as this. 

By attending such symposia, they are working to 

obtain full status as professionals in natural 

resources. Meetings that emphasize women in 

natural resources raise the consciousness level 

that they are indeed professionals. For those of 

us with a Ph.D., "full status" means the "rights, 

privileges and prerogatives thereofH--and it must 

be a two-way street. We give our loyalty, time, 

and energies to our institutions; our employers 

must respond in kind. This symposium testifies 

to the fact that the day of the "token woman" is 

gone and that women indeed belong right where 

they are, in the jobs in natural resources that 

they love. 

So why are we here? We are here because increasingly women are being given equal employment 

opportunities in the profession: women are highly 

competitive, they have a lot to offer the profession, and they are changing the workforce. Thus, 

women are making a statement. Times have changed 

in the United States, and the natural resources 

profession is out of balance in regard to the 

ratio of men to women. This conference represents 

women who are working in the profession and bringing it into balance. Women in natural resources 

research cover the spectrum. They graduate from 

universities to the Forest Service and other 

government employment, to industry or private 

enterprise, and to faculty and other research 

positions in universities. 

There are many objectives for this symposium. 

The first is to focus on women scientists and 

their research findings. Of importance, this is 

to be accomplished in the same manner as it would 

be at national or international meetings within 

each discipline. The second is to establish 

communication links among women and men who are 

interested in helping women obtain and remain in 

employment in which to grow, to develop, to make 

contributions, and to advance in their careers. 

Some call this networking. The third major objective is to involve women graduate students so 

they can meet women who are already on the research career ladder. They need to know women are 

a positive force that is needed in this area of 

scientific endeavor called forestry and natural 

resources. This symposium is an excellent opportunity to see women as active professionals, and 

where graduate students may find role models or 

mentors. Natural resources is a satisfying 

profession and it needs the support of women to 

remain a strong, vital, and dynamic enterprise in 

these great United States. Each one here may add 

other reasons for attending and, whatever they 

are, we are happy you came and hope you come away 

with much more than you gave--the same as I did 

from the first symposium in Burlington, Vermont. 
WOMEN IN NATURAL RESOURCES 

R, Max Peterson, Chief, Forest Service 

U.S. Department of Agriculture 

ABSTRACT.,,The importance of the work being shared at this 

conference is not that it was produced by women, but that 

it is a contribution to science, Conferences that spotlight 

the high quality of work being done by women scientists will 

help breakdown stereotypes and encourage other women to 

pursue excellence in professions previously dominated by 

males, As we move closer to the goal of equal opportunity we 

must not lose respect for individual differences. It is 

the diverse backgrounds of a well-integrated society that 

provide unique perspectives, insights, and solutions to the 

chal 1 enges we face. 

I am delighted to be here, and honored to be 

the keynote speaker at this conference. I am 

impressed with the depth and breadth of the 

papers being presented. The topics are certainly 

worthy of widespread review. It is both 

encouraging and disappointing that papers of this 

caliber are being presented at a conference 

primarily aimed at and organized by women. I 

look forward to the day when the number and 

quality of scientific contributions by women is 

so much a part of major scientific events that a 

separate seminar would simply not be considered 

necessary or appropriate. 

This conference is encouraging because it 

provides a showcase for the high qua1 ity work 

being done by women in natural resource 

management and research. It also provides an 

opportunity to celebrate the fact that there are 

an increasing number of women scientists who are 

making significant contributions to forest 

science. 

The history of women in science is long and 

illustrious, dating back at least to Madame 

Curie's pioneering contributions to the study of 

magnetism, radiation, and atomic structure and as 

recent as the success of Rita Levi-Montalcini 

(LEV1 MONT-ALCHEENEE) , who, a1 ong with her 

partner Stanley Cohen, received this year's Nobel 

Prize for Medicine for their work studying cell 

growth and the orderly development of tissue. 

By the way, I think there is an interesting 

side note to these two examples I used. Madame 

Curie was educated in Poland but couldn't find 

work as a scientist until she moved to France and 

married Pierre Curie. In other words, the 

hurdles to overcome for a female researcher were 

almost insurmountable then. If her husband had 

not sponsored her, it is doubtful that she would 

have been given the opportunity to make the 

contributions she made. 

In the more recent example, Ms. 

Levi-Montalcini said that she had to do most of 

her early research at home. Her ethnic 

heritage did not a1lol.i her to take the same 

path to success that her research pdrtner 

took. 

Fortunately for a1 1 of us, des~i te the 

fact that these two sreat scientists dia suffer 

discrimination, they were able to overconie 

adversity. That brin5s me to the first point 

I'd 1 i ke to make today--a society that a1 lows 

or encourages contributions from scientists 

from only one sex, or race, or ethnic 

background is doing itself a great disservice. 

Its progress as a society will assuredly be 

retarded. 

We face many important challen5es in the 

area of natural resource management. We need 

the best scientists, the best researchers, the 

best minds searchincj for solutions that will 

allow this and future generations to prosper. 

And we need the push for excellence thdt only 

comes from open competition to move up 

organizational 1 adders or to get financi dl 

grants, or to receive other opportunities and 

recognition. 

That open competition has been a long time 

coming in professional and scientific 

organizations that traditional ly were dominated 

by white males, and the Forest Service was no 

exception. 

I prorriise I won't go on at length about 

our numerical success in providing 

opportunities for women-- I feel that tic ki ncj 

off numerical strength often displays more 

about an organization's failure than it's 

success--any number that doesn' t display full 

equal i t y i s really a reflection of how far we 

have yet to go! hevertheless, for the sake of 

reference, I do kant to provide some 

statisitical accounting of the progress women 

are making in developing careers in natural 

resource sciences . 
The first woman scientist hired by the 

Forest Service, Eloise Gerry, undertook wood 

structure research at the Forest Products 

Laboratory in 1910--the same year the Laboratory was established. In 1978, Susan Kossuth became 

the first woman to head a Forest Service research 

project. That was a long time coming! 

It was 1932 before a woman graduated with a 

degree in forestry. She found employement in 

biology, since the notion of women actually 

working in forestry was still too radical to 

entertain. 

The first woman professional forester was hired by the Forest Service in 1957--eight years 

after I started work in the Forest Service. That 

was a long time in coming too! To finish the 

milestones, the first female District Ranger was 

selected in 1979, and the first female Forest 

Supervisor was appointed in 1985. 

How long before we have our first female 

Chief? Well, there's no doubt in my mind that 

one of my successors will be a woman. The examples of slow progress that I've just 

cited a1 1 pertained to the Forest Service. 

However, the track record for other government 

agencies, u~iversi ti es , and private businesses 

could be written in the same lackluster manner. 

Fortunately, women are making great strides 

today in the natural resource sciences and are 

assuming their rightful place as innovators, 

managers, and 1 eaders. However, the true success story cannot be found by simply examining how 

many women or other minorities are entering the 

natural resource sciences. 

That success must be measured not by how we treat everyone as equal s--I see providing 

equality as a moral and ethical 

responsibility--but by how well we acknowledge 

and use everyone's unique talents and know1 edge. 

For today, I'd like to focus attention on open 

competition, not only as a moral imperative, but 

as a contribution toward our soci a1 we1 1-being. 

As women, Blacks, Hispanics, Asians, Native 

Americans, and other minorities first started 

moving into the sciences, the emphasis was not on 

learning from them, but in fitting them into 

positions that were once held almost totally by 

white ma1 es. We often missed the boat by not 

taking advantage of the new resources being made 

available for the benefit of us all--qualified 

professionals with a particular perspective, with 

particular insights, and with unique solutions to 

chal lenges he faced. 

I think the benefits to be achieved from 

equal opportunity are especially important in the 

natural resources sciences. We have a good 

understanding of basic scientific principles. 

What we don ' t know is who wi 1 1 , or how someone 

will, take these basic principles, rearrange them 

according to their unique vision, and realize a 

major breakthrough in solving current problems. 

No one can really predict these kinus of 

scientific breakthroushs. No one picked 

Einstein out as a child who wohld somedaq 

provide major insights into how our world 

operates. Even now, no one knows what caused 

his to visual ire the real lty of e=mc2, but 

where would the discipline of pnjsics be toda~ 

if Einstein had been prevented from workins in 

his chosen science? 

! said earlier that I was delishtea to be 

here. The reasons transcena mj position as 

Chief, and they transcend my career in the 

Forest Service. Some of those reasons can be 

traced to my role of father of three aau5hters 

and one son. As a parent, I felt that my 

childrens'aspi rations and capab~l I ties should 

not be limited or shaped ~y their sex. I 

think that's the real underlying messase of 

this conference. 

A society doesn't reach its potential 

until all of its members have the opportunity 

to reach their potential. Freedorti means thdt 

a minimum of restrictions are placea on the 

individual. The number of wor;ien in natural 

resource sciences is not representative of the 

number of women in our society. I think this 

is due in part to the fact that, in the past, women were not encourayea to enter the 

sciences. So some of the problems we face 50 

back to elementary and high school. 

Research has shown that our expectdtions 

of others play a large role in deterriiin'rns 

behavior. For example, teachers who were tol~ 

that a class they were about to start teach~ng 

was coriiposed of very brisht students tended to 

have a class that excelled, Similarly, if we 

expect that we can attract top-notch wonien in 

science, we will attract more top-notch fenidle 

students. 

When I was in school, relatively few 

women studied natural resource sciences or engineering , . . they weren't expected to! 

There were no women foresters, engineers, or other scientists in my graduating class. 

Women were in the traditional schools of 

journal ism, nursing, education, and so on. Perhaps conferences such as this will raise 

a1 1 of our expectations. 

Without downgradi ng the seriousness of 

the obstacles in your paths, I think some 

obstacles for women are self-imposed, just ds 

they are for men. In my job, I set asked by a lot of peoble about career plannins, I aia a 

videotape setting out my basic adv~ce, and it 

should be widely available--at least in each 

of the Forest Service's Regions and Stations. 

If you haven't seen it, 1 hope you'll ask to 

have it shown. Because my advice pertains to 

women as well as men, I'd 1 i ke to share some of my career counsel in9 thoughts with you. 
When ycu're trying to build a career, 1 

recommend you look at what the organization or 

field of study is 1i kely to need in terns of 

future talent. For example, if an organization 

will be going through an expansion, it will 

reward those employees who are flexible and fast 

learners, If an organization is stable or if it 

is ging through a period of austerity, it will 

seek out those employees who have built a breadth 

and depth of expertise that will allow jobs to be 

done more effectively, If an organization must 

deal with high priority national problems such as 

acid rain, it will seek ou~eople who are adaptable and have an interest in he1 ping provide 

solutions. 

A second bit of advice I would pass on is 

that nothing succeeds like success, To find out 

how you can benefit your career, talk to people 

who have been successful. Find out the 

ingredients of their success. I think each 

successful person will tell you some of the same things, such as: 

I, It" important to work as part of the 

team. 

2. It's important to be able to communicate 

we7 7 , incl udi ng 1 istening. Interpersonal ski 11s 

are important in every position in an organizatio~. 

3. It's important to have a positive 

attitude. There's an old saying, "Smite and the 

world s~iles with you," There's a lot of truth 

to that. NG one advocates bejny blind to 

difficulties, but successful people tend to see 

the difficulties as challenges to be overcome, 

not problems to run from. As a variation on the 

notion of positive thinking, 1% sure each of you 

has been in a situation where someone else got 

credit for your work, or someone else with the 

same qualifications got a better deal than you. 

It happens, Everyone gets imposed on at some 

time. How you handle such situations may be 

important to your success. Cynicism and 

pessimism are poisons to good ideas and good 

people. 

Another piece of advice I pass on to people 

trying to build a career is that you need an 

orientation to the future. Traditions are 

important. Integrity is a must. Respect for 

other individuals is essential, but the one thing 

you can't do if you want to move forward is to 

live in the past. It" always a mistake to think 

a situation is temporary, and someday we can all 

go back to the "good old days," You can't. The 

successful people are movi ng toward tomorro~j and 

he1 ping I ead the way. 

A final bit of advice for people, both men and women, who are interested in building a 

career is that you mast develop a broad 

orientation or perspective to your work. 

Uhatever your job is, it's important to 

understana the nature of your or5anizat ion ; how 

others Pit into the picture--what their 

responsibil i ties are; and how many di fferent 

jobs or tasks compose your particular fiela of 

enceavor, 

There's a popular notion that if you are 

goins to advance in your career, you must learn more and n;ore about your particular field. 

That's not always true. The climb up the career ladder is not a1 ways a straight line. I 

think the opportunitj of gainin5 a broader 

perspective is one of the side benefits to the 

i nterdi sci pl i nary process i ncreasi ngl y useu 

both in research and in operdting programs. by 

working to5ether, you can learn the concepts, 

ideas, and scientific principles of several 

disciplines. There is a cross-fertilization of 

skills and abilities. It is sometimes 

surprising to see the benefits of working, with 

others. 

A good example is in the field of medicine 

and electronics. kho would have thou5ht years 

ago that someone with an h.0. degree would yo 

back to school to studj electronics, or be 

working closely with an electrical en9ineer to 

jointly analyze problen~s and seek solutions? 

Or, who would have thousht that an electrical 

engineer would have to learn about how the 

human booy functions to work effectivelj with a medical team? Today, the pacemaker ana 

electronic ana nucl ear diagnostic equipment are just examples of the synergism of 

interdisciplinarj approaches. 

interdisci pl inary approaches. 

There's one other major topic I want to cover here today. That is the notion thiit 

while we strive for open competition and 

equality, we must not lose respect for 

differences. blanagers have a very difficult 

job in this regard. They must recocjnize 

differences in a constructive way without 

appeari ncj to create separate categories. There 

are di f ferences between how men and women, or individuals from various ethnic backgrounds, 

will function on a job. 

Within the last year, I was at a meeting 

and one of the District Rangers came to me and 

told me that we have another "first" in the 

Forest Service--our first presnant District 

Rantjer. She was pregnant, ana she told me about some of her plans, such as workinc, ~vith 

her assistant to appoint an Acting Ranger 

durins her maternity leave. So we had a new situation we had to deal with, and there are a 

lot of those that Gifford Pinchot never had to 

deal with, So we couldn't look at traditional 

approaches. This didn't mean it wds a serious 

problem--it was merely a new one. 
We have to ask what we can do so women are 

not forced to make a decision between having a career or having a family. Of course, when 

concessions are made in this direction, the 

question arises about the rights of men to also 

be given time off for paternity leave. 

We have to ask what can be done to lessen 

the trauma of a career move in a two-career 

family, In this regard, we%e launched a dual- career family policy which makes it possible that 

if one member transfers, the other is found 

appropriate employment in the new location, 

However, this presents the possibility that the 

dual -career family pol icy penal izes the single 

person. With the number of dual-career families 

at an a1 I-lime high, and with a growing number of 

people delaying marriage to build a career, you can see the difficulty of the questions we are 

facing. 

I am looking forward to hearing some of the 

other speakers present their papers, The scope 

of this conference indicates that we have made 

good progress in achieving our goal of equal 

opportunity. Let me highlight some of the ideas 

I've presented today. 

While the theme of the conference is women 

in science, the importance of the work being 

shared here is not only that it was produced by 

wonen, but that it is a contribution to sclence, 

The ckallenses we face in the natural resource 

sciences are too diff~cult For us to exclude anj 

element OF society Prom the search for solutions, 

I a1 so mentioned that in our race to achieve 

statistical success, he so~etimes overtook 3 ;are 

critical value in having people with diverse 

backgrounds working together--that is, that 

diversity allows for a cross-fertil ization and 

expansion of ideas, 

I tried to offer some key points I have 

found useful in building a professional ii fe, and 

I discussed some of the dilemmas we face as we try to find solutions that will provide eqml 

opportunities for all. 

Once again, let me congratulate all of you 

for putting together a very impressive 

conference, By s pot1 i ghting the accompl i shments 

of some of our women scientists, you are 

encouraging others to fol low in their footsteps. 
Use of Models in Resource Management 1 

Katherine C. Ewe1 2 

Abstract. --Use of models for resource management 

is increasingly appropriate because of the growing 

complexity of resource management issues. Three 

factors limit the complexity of models that are 

constructed to address these issues: the amount of 

information necessary to construct and simulate 

the model; inherent error in the integration 

process; and the advisability of restricting the 

range of turnover times of the state variables 

that comprise the model. Models that describe 

only one or two basic processes in an ecosystem, 

such as decomposition, may be useful in spite of 

their simplicity. More complex models that 

describe entire ecosystems are often most useful 

if they are part of an on-going research project. 

Models of entire landscapes may be less complex 

than ecosystem models because of greater 

aggregation of state variables, but they are 

useful nonetheless for exploring management 

implications. 

Keywords: Simulation model, non-linear 

differential equations, integration error, 

aggregation 

With increased population pressure and a 

shrinking land base, resource management has 

become more dependent on active manipulation not 

only of ecosystems but often of entire landscapes, 

even for maintenance of "natural" conditions. The 

ability to do this, however, requires-an 

understanding of simultaneously interacting 

factors such as climate variables, primary and 

secondary productivity, nutrient cycles, water 

availability, and fire frequency, as well as the 

perturbations introduced by management. It can be 

extremely difficult, however, to perform the 

necessary integration mentally. With increased 

availability and diversity of computers, the 

ability to conceptualize, to express 

mathematically, and to explore the multitude of 

relationships among components in managed and 

natural ecosystems, watersheds, and even 

landscapes has increased greatly. 

These interactions can be explored effectively 

by constructing and simulating computer models. A 

model is an abstraction of reality: a 

simplification of a complex system. The 

mathematical models that I will discuss are sets 

of non-linear differential equations that express 

inflows and outflows from the components (state 

variables) that comprise a unit of the landscape, 

such as an ecosystem, that is assumed to be 

discrete, Simulation of such a model for 

exploring resource management practices requires 

estimating the magnitudes of the state variables 

and their flows and expressing the precise 

relationships among the state variables and other 

factors (such as climate) that govern them. 

SCOPE AND USEFULNESS OF MODELS 

The complexity of a model should be limited as 

much as possible to ensure its usefulness. Two 

factors set these limits. First, each interaction 

and/or process that is included in a model must be 

described in the equation, and its magnitude must 

be estimated. Because equations for most state 

variables contain at least two flows (usually 

more), each of which may include one or more 

interactions with other components, the amount of 

information required to support the equations 

mounts rapidly as the number of state variables 

increases. Second, there is usually no precise 

analytical method for solving systems of nonlinear 

differential equations. (The major exception is 

use of an analog computer, which usually limits 

the size and complexity of a model.) Using a 

digital computer is inherently inaccurate, 

requiring discrete time steps rather than 

instantaneous solutions. Although the amount of 

integration error can be reduced by selecting 

small time steps andlor sophisticated integration 

routines, rounding error also accumulates at each 

integration, at least partially offsetting any 

increased accuracy. Consequently, a larger model 

carries the potential for greater cumulative 

error. Because the relative importance in the 

model of feedback mechanisms, such as predation, 

and forcing functions, such as climate variables, 

may vary, there is no straightforward association 

between the accuracy of a model and its 

complexity. Nevertheless, it is clear that a 

modeler should relinquish simplicity with great 

reluctance. 

A model should be constructed so that its state 

'presented at the Symposium on Current Topics in variables have turnover times that are 

approximately the same order of magnitude. Forest Research: Emphasis on Contributions by 

Women Scientists. Equations simulating the behavior of state 

7 variables with widely varying - - turnover times 

"~rofessor of Forestry, University of Florida, (e.g., algae and trees) are called "stiff" 

Gainesville, FL 326 11. equations, and they may be unstable, not providing 
any useful information about the real system. Two 

approaches for incorporating such state variables 

are available. A portion of a model can be 

excised as a subroutine and solved with a 

different time step, e.g., an hourly 

photosynthesis module in a model that includes 

annual changes in plant biomass. But it is then 

difficult to allow the simulated processes in the 

subroutine to interact significantly with the rest 

of the model, and the two become fairly 

independent. Moreover, the subroutine with the 

shorter turnover time, which is ostensibly 

introduced to increase accuracy, may in fact be 

subject to greater error because of integration 

error, as described above. The second approach is 

to incorporate state variables with short turnover 

times into a general, aggregated state variable 

(e.g., including phytoplankton and macrophytes as 

"plant biomass" in a lake model). The risk is in 

losing details that may be significant (such as 

the relationships between phytoplankton and 

consumers that may change in very short time 

periods). Unfortunately, there is no easy method 

for selecting the appropriate level of resolution; 

the choice must be based on the system being 

simulated and the issues or questions that the 

model is intended to address. 

Lack of a data base should not deter model 

construction. Clearly, a strong data base and 

independent validation are necessary if a model is 

to be used to establish actual management 

practices. However, a model may also illustrate 

the range of behavior patterns a system may follow 

under a variety of possible values for both state 

variables and processes, providing insight into 

the structure and function of an ecosystem as well 

as direction for further research efforts, 

Consequently, the purpose of the model should be 

considered before judgement is made about the 

extent of its data base. 

Models may therefore differ in complexity, the 

scale of processes that are included in them, and 

the amount of data that support them. The 

strategy of determining the appropriate level of 

complexity, deciding on the appropriate time and 

geographic scales, and dealing with a large or 

small data base must be determined for each model. 

Five models that describe a broad range of 

complexity (1 - 21 state variables) are outlined 

in Table 1 and are described below to illustrate 

these points. 

PROCESS MODELS 

Although many resource management models may 

focus on specific ecosystems, simple models that 

describe important processes within an ecosystem 

may be of interest to resource managers. One of 

the first ecological models to be simulated (Olson 

1963) describes the process of litter 

decomposition: 

Table 1. State variables included in five resource management models. 

PROCESS MODEL ECOSYSTEM MODELS LANDSCAPE MODELS 

Litter Florida Pine 

Decomposition Plantation 

Labile biomass Pine foliage 

Refractory Pine stems 

biomass and branches 

Pine coarse roots 

Shrubs 

Herbs 

Litter and humus 

P in pine foliage 

P in pine stems 

and branches 

P in pine roots 

P in shrubs 

P in herbs 

P in litter 

Available 

inorganic P 

Total inorganic P 

Soil water 

Deep aquifer 

Florida 

Lake 

Commercial Tropical 

Forest Watershed 

Phytoplankton Foliage Land in forest 

Macrophytes Stems and branches Land in coffee 

Macrophyte Coarse roots Land in pasture 

storage organs Fine roots Human population 

Epipelic algae Litter and humus Soil moisture 

Zooplankton Soil organic matter Sediments 

Benthic invertebrates Understory 

Omnivorous fish 

Adult primary 

predator fish: 

biomass and numbers 

Young primary 

predator fish: 

biomass and numbers 

Adult secondary 

predator fish: 

biomass and numbers 

Young secondary 

predator fish: 

biomass and numbers 

Number of white amur 

Particulate dead 

organic matter 

Detritus 

P in detritus 

Inorganic P: 

epilimnion and 

hypolimnion 
This general model defines the decomposition 

constant, k, as an index of the rates at which 

dead organic matter (Q) decays and, indirectly, 

nutrients may be remineralized in the litter 

layer, a fairly discrete subsystem of many 

ecosystems. The accuracy of this model is 

increased by the use of two state variables rather 

than one (see Table I): labile organic matter (A), 

which decays rapidly, and refractory organic 

matter (B), which consists primarily of structural 

materisl and decays more slowly: 

dA/dt = -kl * A dB/dt = -k2 * B 

This simple model was used to demonstrate the 

apparent impact of wastewater disposal on foliage 

quality as well as on decomposition rate (Dierberg 

and Ewel 1984). However, doubling the number of 

state variables also doubles the number of 

estimates necessary for simulation: the proportion 

of each of the components as well as the decay 

rate of each, This two-variable model has also 

been used to establish confidence bands for 

estimates of the two decay rates that describe the 

decomposition process (Portier and Ewel 1981). 

ECOSYSTEM MODELS 

Constructing and simulating a model of an entire 

ecosystem may serve any or all of three purposes: 

to test the feasiblity of hypotheses about 

ecosystem dynamics; to determine priorities for 

future research by examining the behavior of the 

components of a model; and to predict the 

consequences of proposed management practices. 

Consequently, the data base required for a model 

may range from minimal to extensive based on the 

degree of use that the model may receive, 

A model of a managed slash pine (Pinus elliottii 

Engelm,) plantation was constructed over a period 

of several years, as the information about 

magnitudes of carbon and nutrient storages and the 

nature of the interactions among carbon, 

phosphorus, and water cycles slowly increased. 

The earliest version of the model (Ewel et al. 

1978) was developed from a very small data base 

and an understanding of basic ecosystem processes. 

Expansion of the model as the data base increased 

improved the resolution of this model (Table I; 

Golkin and Ewel 19841, and pinpointed belowground 

processes as the most important target for future 

research. Further development has led to a 

partially validated, l-yr version of the model 

that continues to serve as a tool for setting 

research priorities and may eventually become a 

management tool, 

When data-gathering and model building are 

simultaneous, model development may be much more 

rapid, and all three goals may be realized. The 

carbon and phosphorus dynamics in a Florida lake 

that had been invaded by an exotic aquatic plant 

(Bydrilla verticillata Royle) were simulated as 

part of a large-scale research effort that 

included documentation of annual patterns in water 

quality and plant and animal populations. By incorporating into a single model the dynamics of 

major groups of plant and animal populations, dead 

organic matter, and organic and inorganic forms of 

phosphorus (see Table I), it was possible to 

demonstrate that addition of a fish that eats 

aquatic weeds could increase the biomass of 

benthic invertebrates and of game fish such as 

bass, increase the water quality, and increase 

turnover rate of carbon in spite of decreased 

photosynthesis rates (Ewel and Fontaine 1982, 

1983). Once validated, such a model could be used 

to determine specific management strategies for 

aquatic weed control. 

This model, however, contains state variables 

that span a wide range in turnover times: from 2 

hr for carbon incorporated in phytoplankton to 29 

days for carbon incorporated in omnivorous fish; 

turnover times for inorganic dissolved phosphorus 

and for detritus represent an even broader range. 

The combination of widely varying turnover times 

and the damping of programmed climate factors by 

the aqueous environment decrease the stability of 

the model, particularly when it is simulated for a 

Long time, and therefore compromise its usefulness 

for exploring a broad range of potential 

management strategies. The pine plantation model 

has a greater probability of usefulness for 

management because the ecosystem is structurally 

more simple, and hence easier to express in a 

model, and because of the importance that climate 

plays in regulating inflows, outflows, and rates 

of processes in the structure of the model. 

The usefulness of these ecosystem models is not 

restricted to management, however. The results 

also outline the general patterns and magnitudes 

of carbon, nutrients, and water cycles, serving as 

a basis for comparison not only with similar 

ecosystems but among ecosystem types as well. The 

following general carbon budgets derived from the 

two ecosystem models described above demonstrate 

the differences in magnitude and apportionment 

that can occur: 

Florida Florida 

Components and Processes Pine Forest Lake 

Live plant biomass (tiha) 8.0 0.4 

-1 -1 Plant respiration (t ha yr ) 1.2 0.7 

Increase in- ive biomass -1 1 

(t ha yr ) 0.8 0 

-1 -1 Grazing (t ha yr ) 

Detritus pro uction -1. -(ii (t ha yr 1 

LbTDSCAPE MODELS 

Expanding an ecosystem model to incorporate the 

patterns found throughout a landscape need not 

require increased complexity. An aggregated 

version of the slash pine model was constructed to 

explore the implications of different kinds of 

forest management practices on large scale carbon 
storage patterns in commercial forests (Table I). 

Nutrient and water cycles were omitted, replaced 

by factors in the carbon fixation term that 

account for fertilization and latitudinal changes 

in evapotranspiration. Simulating this relatively 

simple model (seven state variables and l-yr age 

classes for the pines) resulted in a broad 

spectrum of uses, from verifying a hypothetical 

decomposition rate for soil organic matter 

(Cropper and Ewel 1983) to predicting the 

magnitude of decline in carbon storage patterns 

that could be expected if Florida plantations were 

intensively managed for biomass production 

(Cropper and Ewel in press). The model was 

sufficiently general to be applied to a similar 

analysis of the impacts of forestry practices on 

carbon cycling in the Pacific Northwest (Cropper 

and Ewel 1984). Although this general a model 

cannot compensate for site-to-site differences 

among individual forests, it expresses the general 

patterns that can be observed in a landscape. Its 

data base is stronger than the ecosystem models, 

in part because it is much simpler. Its breadth 

in geographic scope is matched by a long timescale. Without having been validated, it has 

suggested potential long-term effects of resource 

management strategies on global carbon storage 

pat terns. 

Many processes that can be expressed in 

considerable detail at the ecosystem level can be 

aggregated at the landscape level. A model 

simulating population growth and related changes 

in land use patterns in a Large tropical 

watershed, and their impacts on sedimentation in a 

proposed downstream reservoir in the Dominican 

Republic was constructed by assembling simple 

models of population growth, land use change, and 

water balances (Table I; Antonini et al. 1975). 

This model had only six state variables. The data 

base was sufficient to program historic land use 

changes, population growth, and climate. Although 

it was too general to predict the specific 

lifetime of the reservoir, the model was useful 

for comparing relative impacts of a series of 

government policies, such as controls on forest 

harvesting, other land use conversions, and 

emigration, that would affect population and land 

use in the watershed. It demonstrated the 

importance of interactions among different 

components of the landscape in determining the 

impacts of management strategies. 

CONCLUSIONS 

Neither the degree of complexity nor the 

availability of data need define the usefulness of 

a model in resource management. Very complex 

models with only a small data base can be useful 

in setting research priorities; as the data base 

broadens they become more useful for interpreting 

research data. Very simple models, on the other 

hand, can accurately describe general behavior 

patterns of a portion of an ecosystem or of an 

entire landscape. It is also clear, however, that 

much of the responsibility for making best use of 

a model rests on the shoulders of the modeler. A 

model should not be expected to be more than an 

abstraction of reality, but it can clearly serve 

as a useful tool in probing reality, 

1 thank Wendell P, Cropper, Jr., and Mary Duryea 

for constructive comments on this manuscript. 

LITERATURE CITED 

Antonini, G. A,; Ewel, K, C,; Tupper, H. M. 

Population and energy. A systems analysis of 

resource utilization in the Dominican Republic. 

Gainesville, FL: University Presses of Florida; 

1975. 166pp. + map suppl. 

Cropper, W. P., Jr.; Ewel, K. C. Computer 

simulation of long-term carbon storage patterns 

in Florida slash pice plantations, Forest 

Ecology and Management 6:101-114; 1983. 

Cropper, W. P., Jr.; Ewel, K. C. Carbon storage 

patterns in Douglas-fir ecosystems. Canadian 

Journal of Forest Research 14:855-859; 1984. 

Cropper, W. P, Jr.; Ewel, K. C. A regional carbon 

storage simulation for large-scale biomass 

plantations, Ecological Modelling (in press); 

1987. 

Dierberg, F. E.; Ewel, R. C. The effects sf 

wastewater on decomposition and organic matter 

accumulation in cypress domes, In: Ewel, K. 6.; 

Odum, H. T., eds. Cypress swamps; Gainesville, FL: 

University Presses of Florida; 1984:164-170. 

Ewel, K. C.; Fontaine, T. D. 111. Effects of white 

amur (Ctenopharyngodon idella) on a Florida 

lake: A model. Ecological Modelling 16:251-273; 

1982. 

Ewel, K. C.; Fontaine, T. D. III. Structure and 

function of a warm monomictic lake. Ecological 

Modelling 19:139-161; 1983. 

Ewel, K. C.; Hood, S. J,; Myers, R. L. 1978. 

Simulation of dynamics of a managed slash-pine 

ecosystem on poorly drained soils. In: Hollis, 

C. A.; Squillace, A. E., eds. Proceedings of the 

Fifth North American Forest Biology Workshop; 

1978 March 13-15; Gainesville, FL. School of 

Forest Resources and Conservation, University of 

Florida, Gainesville; 19783375-388. 

Olson, J. S. Energy storage and the balance of 

producers and decomposers in ecological systems. 

Ecology 44: 322-331; 1963. 

Portier, K. M.; Ewel, K. C. Confidence bands for a 

regression-based, non-linear decomposition 

model. Ecological Modelling 14:125-132; 1981. 
Advances In Modeling Silvicultural Treatments 

In Loblolly Pine standsi 

2 Marilyn A, Buford 

Abstract,--Accurate prediction of stand growth and 

yield requires a thorough understanding of the 

effects that various silvicultural treatments have 

on stand structure and development. Tree improvement, thinning, site preparation and fertilization 

have been shown to change the shape and/or level of 

growth curves. Therefore, modeling success can be 

best achieved where emphasis is placed on the 

effect of those treatments on the basic relationships underlying stand growth and development 

and validation against long-term data. 

Many silviculturalists are interested in treatments or combinations of treatments that increase 

production efficiency, Efficiency is improved if 

there is a reduction in production cost per unit 

of a desired quality. For a forest crop, that 

reduction can be measured directly in dollars. 

Costs associated with a silvicultural regime 

include the operational costs of cultural treatments, costs of installing studies to document 

treatment effects, costs of waiting for operational or research results, and costs of taking a 

wrong action. These costs make mathematical 

models of stand growth necessary tools for projecting probable treatment effects and resulting 

yields. To be useful for extrapolation, a model 

must reflect observed or quantified behavior of 

stands over the long term. This paper briefly 

outlines loblolly pine (Pinus taeda L.) stand 

behavior and reviews several recent advances in 

modeling silvicultural treatments in loblolly pine 

s Lands. 

BEHAVIOR OF LOBLOLLY PINE STANDS 

Much of what is known about the development of 

loblolly pine stands is derived from long-term 

observations in density-control studies installed 

at very early ages in natural stands and from 

planted spacing studies. Examination of long-term 

results provides much information about the 

effects of height growth, initial density, and the 

interaction of these factors in stand development. 

The following are observations from loblolly 

pine stands of the same initial density: 

a. Stands on poor sites contain more trees 

per acre than stands on better sites at the same 

age (Figure 1); 

b. At the same mean height of dominant trees, 

stands on better sites contain more trees per acre 

than stands on poorer sites (Figure 2); and 

c. Better sites can support higher basal areas 

than poorer sites. 

'Presented at the Symposium on Current Topics in 

Forest Research - Emphasis on Contributions by 

Women Scientists. November 4-6, 1986. 

Gainesville, Florida. 

2 Research Forester, USDA Forest Service, 2730 

Savannah Highway, Charles ton, SC 29407. 

Given the same site quality, basal areas and volumes produced from stands of different initial densities converge, cross over, and decline (Figure 

3) 

Mean annual increments of both volume and basal 

area culminate earlier on better sites than on poor 

sites and at higher initial densities than at lower 

initial densities. These observations and trends 

are apparent in the compiled information from longterm density studies (Balmer et al. 1975, Harms 

and Lloyd 1981, Gilmore and Gregory 1974, Arnold 

1978, Arnold 1981, Sprinz et al. 1979, Hafley 5 - al. 1981, Buford and Hafley 1985, Harms and Langdon 

1976). 

TREATMENTS 

Silvicultural treatments have three classes of 

goals: I) manipulating the tree directly by genetic improvement, 2) improving the competitive 

environment by thinning or weed control and 3) 

improving the chemical and physical environment by 

site preparation or fertilization. Advances in 

modeling these treatments rest on determining their 

effect on relationships basic to stand 

development, 

Tree Improvement 

Using long-term, block-planted genetic studies to 

investigate the effects of tree improvement on 

loblolly pine stand dynamics, Buford (1986) and 

Buford and Burkhart (1985) found that: 1) for seed 

sources and families, the shape of the height-age 

curve is dictated by the site, but the level of the 

height-age curve is dictated by the seed source or 

family (Fig. 4); 2) for seed sources and families, 

the shape of the height-diameter relationship at a 

given age is determined by the site and initial 

density, while the level of the height-diameter 

relationship is determined by the seed source or 

family and is directly related to the dominant 

height of the seed source or family at that age; 

and 3) if silvicultural treatments are the same and 

are equally successful, variances of height and 

diameter in stands originating from selected genotypes are not different from those in genetically 

unimproved stands. The implications for modeling 

growth of stands originating from selected genotypes are: 1) genetic improvement of trees affects 

the rate at which stands develop, but does not fundamentally alter the pattern of stand development 

from that of unimproved stands; 2) changes in genetic material on a given site will likely affect the 

level, but not the shape, of basic associations 

such as the height-age and height-diameter rela- 
tionships; and 3) correctly characterizing the 

height-age profile is crucial. In general, growth 

of genetically improved loblolly pine can be 

modeled by altering the height-age curve in 

current growth and yield models to reflect differences in the level, or site index, attained by 

different sources or families (Buford and Burkhart 

1986). At present, there is a major effort to 

identify key hypotheses about dynamics of stands 

of genetically improved stock and to determine the 

most efficient experimental means to test those 

hypotheses (Nance et al. 1986). 

Thinning 

Several diameter distribution models have been 

developed which include a thinning component. 

Thinning is accomplished by truncating the 

diameter distribution or by removing certain proportions of stems from specified diameter classes. 

Height is predicted from a height-diameter 

equation and is not among the thinning criteria. 

Examples of this type of model are given by Matney 

and Sullivan (1982) and Cao et al. (1982). 

An individual tree model treats the stand as 

an aggregrate of separate trees, each having specific characteristics. Such a model for loblolly 

pine stands was presented by Daniels and Burkhart 

( 1975). In this model, thinning was accomplished 

by removing individuals meeting specified criteria 

from the diameter distribution. Although the 

individual heights are known, height was not used 

in thinning decisions. In the models discussed 

above, stand parameters are not functions of initial density or spacing, but of the number of surviving trees at any given time. 

A model for thinned stands mathematically 

derived from a model for unthinned stands was presented by Hafley and Buford (1985). The stand is 

modeled as a bivariate distribution of heights and 

diameters with stand characteristics predicted 

from age, initial density, and dominant height. 

The model shows the convergence of basal area and 

volume observed in long term density studies. 

Thinning was accomplished by manipulating the 

bivariate distribution so that thinning decisions 

are based on height and diameter. The model was 

validated using data from long-term thinning studies. It closely predicted height and diameter 

distributions for 25 years after thinning under 

various regimes (Smith and Hafley 1986). by 

decisions made in developing this model were that 

the growth of all stand characteristics, including 

height, is affected by initial density, that 

height growth effects the growth of other stand 

characteristics and, therefore, that height should 

be considered in thinning decisions. 

Fertilization and Site Preparation 

Recent results from the Lower Atlantic 

Coastal Plain indicate that both bedding and 

phosphorus fertilization alter the shape and level 

of the height growth curve on a given site. 

Results at ages 10 and 15 from a study in South 

Carolina (McKee and Wilhite 1986, Buford and McKee 

1986) and at age 13 from a study in North Carolina 

(Gent et al. 1986) consistently show differences 

of 10 feet or more in average height (at ages 10, 

15 and 13) between bedded plus phosphorus and 

control treatments. Differences in the shape of 

the height-age profiles are more pronounced among 

treatments on the wetter sites (McKee and Wilhite 

1986). Indications are that progress can be made 

in modeling these treatments by quantifying the 

effects of changes in the soil chemical and physical properties on the height growth profile. 

CONCLUSIONS 

This paper has presented a compilation of observations on loblolly pine stand development. 

Advances in modeling silvicultural treatments such 

as tree improvement and thinning have been made 

where emphasis has been placed on the effect of the 

treatment on basic reLationships underlying stand 

growth and development. Progress in yield projection will continue if the emphasis in model 

building is placed on understanding changes in the 

underlying relationships of stand dynamics and 

validating the resulting models against long-term 

data. 

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LITERATURE CITED 

Arnold, L. E. Gross yields of rough wood products 

from a 25-year-old loblolly and shortleaf pine 

spacing study. Forestry Res. Rep. 78-7. Urbana 

Champaign, IL; University of Illinois 

Agricultural Experiment Station; 1978. 4 pp. 

Arnold, L. E. Gross yields of rough wood pro 

ducts from a 31-year-old loblolly and shortleaf 

pine spacing study. Forestry Res. Rep. 81-1. 

Urbana-Champaign, IL; University of Illinois 

Agricultural Experiment Station; 1981. 4 pp. 

Balmer, W. E.; Owens, E. G.; Jorgenson, J. R. 

Effects of various spacings on loblolly pine 

growth 15 years after planting. Res. Note 

SE-211. Asheville, NC: U. S. Department of 

Agriculture, Forest Service, Southeastern 

Forest Experiment Station; 1975. 7 pp. 

Buford, M. A. Height-diameter relationships at 

age 15 in loblolly pine seed sources. Forest 

Science 32(3):812-818; 1986. 

Buford, M. A.; Burkhart, H. E. Dynamics of 

improved loblolly pine plantations and the 

implications for modeling growth of improved 

stands. 2: Schmidtling, R. C. and M. H. 

Griggs, eds. Proceedings, 18th Southern Forest 

Tree Improvement Conference; 1985 May 21-23; 

Long Beach, MS. Sponsored Pub. No. 40, 

Southern Forest Tree Improvement Committee; 

1985:170-177. 
Buford, M, A,; Bafley, W, L, Probability distributions as models for mortality, Forest Science 

31(2):331-341; 1985. 

Buford, Me A*; McKee, W, A,, Jr, EffecLs of site 

preparation, fertilization and genotype on 

loblolly pine growth and stand structure -- results at age 15, Presented at Fourth Biennial 

Southern Silviculiural Research Conference; 1986 

November 4-6; Atlanta, GA; 1986, 

Cao, Quang V,; Burkhart, Harold E,; Lemin, Ronald 

C,, Jr, Diameter distributions and yields of 

thinned loblolly pine plantations. Pub, No, 

FWS-1-82, Blacksburg, VA; Virginia Polytechnic 

Institute and State University; 1982, 62 pp, 

Daniels, Richard F,; Burkhart, Harold E. 

Simulation of individual tree growth and stand 

development in managed loblolly pine plantations. Pub, No, FWS-5-75, Blacksburg, VA; 

Virginia Polytechnic Institute and State 

University; 1975. 69 pp. 

Gent, J, A,, Allen, H, L.; Campbell, Robert G,; 

Wells, C, 6, Magnitude, duration tion and 

economic analysis of loblolly pine growth 

response following bedding and phosphorus 

fertilization, Southern Journal of Applied 

Forestry 10(3):124-228; 1986, 

Gilmore, A. R,; Gregory, R, P, Nenty years 

growth of loblolly and shortleaf pine planted 

at various spacings in Southern Illinois, 

Transactions, Illinois State Academy of Science 

67(1):38-46, 1974, 

Hafley, W. L,; Buford, M. A, A bivariate model 

for growth an yield prediction tion, Forest 

Science 31(1):237-247, 1985, 

Kafley, W, t,; Smith, W. D.; Buford, M. A, A new 

yield prediction model for unthinned loblolly 

pine plantations, Tech, Rep, No, 1, Bioeeonomic 

Modeling Project, Southern Forest Research 

Center. Raleigh, NC; North Carolina State 

University; 1982. 65 p. 

Harms, W, R,; Langdon, 0, G. Development of 

loblolly pine in dense stands. Forest Science 

22(3):331-337; 1976, 

Harms, William Re; Lloyd, F. Thomas. Stand struc 

cure and yield relationships in a 20-year-old 

loblolly pine spacing study, Southern Journal 

of applied Forestry 5(3):152-165; 1981. 

Matney, Thomas G.; Sullivan, Alfred D. Compatible 

stand and stock tables for thinned and unthinned 

loblolly pine stands, Forest Science 

28(1):161-171; 1982. 

McKee, W, R., Jr,; Wilhite, L. P. Loblolly pine 

response to bedding and fertilization varies by 

drainage class on lower Atlantic Coastal Plain 

sites. Southern Journal of Applied Forestry 

19(1): 16-21; 1986. 

Nance, Warren L,; McCutchan, Barbara G.; Talbert, 

Cheryl B,; Buford, Marilyn A,; Foster, G. Sam; 

Sprinz, Peter, Experimental approaches for 

evaluating genetic effects on stand growth and 

yield. Presented at Workshop of the Genetics 

and Breeding of Southern Forest Trees Regional 

Information Exchange Group; 1986, June 25-26; 

University of Florida; Gainesville, FL; 1986. 

33 PPSmith, W, D.; Hafley, W. I,. Evaluation of a 

loblolly pine plantation thinning model, 

Southern Journal of Applied Forestry 

10(1):52-63; 1986. 

Sprinz, Peter; Clason, Terry; Bower, Dave. 

Spacing and thinning effects on the growth and 

development of a lo blolly pine plant at ion. 

Forestry Research Report; Clason, Terry, ed. 

Homer, LA. : North Louisiana Hill Farm 

Experiment Station. 1979:l-42. 
Ecophysiological Diversity of Ectomycorrhizae 1 

Caroline S. Bledsoe 2 

Pacific Northwest forests present a 

fascinating paradox: low species diversity of 

host trees and high species diversity of fungi. 

It is well known that both the diversity and 

abundance of fleshy fungi (Basidiomycetes and 

Ascomycetes) are tremendous. 

Why are there so many different fungal 

species? Is fungal taxonomic diversity related 

to ecophysiological diversity? For these 

ectomycorrhizal fungi, have they specialized in 

some physiological roles? Are some fungi 

better than others at processes which affect 

their host - such as enhanced nutrient uptake? 

Or alleviation of water stress? This paper 

discusses these questions and presents 

experimental research which answer some of 

these questions. 

Species diversity, we suggest, is related to 

physiological diversity, especially fungal 

physiological processes which can affect the 

host. Historically, ectomycorrhizal fungal 

benefits to the host have been documented in 2 

major areas: water relations and nutrition 

(Harley and Smith 1983, Marks and Kozlowski 

1973, Alexander 1983, Reid and Bowen 1979, 

Parke et & 1983 and many others). 

Therefore, we suggest that some fungi are 

able to take up nutrients more rapidly than 

other fungi and that the host tree will benefit 

from this increased ability of the fungi. 

Similarly, some fungi may be better able to 

take up water from the soil and relieve plant 

water stress than other fungi. In the 

following sections, we discuss linkages between 

fruit bodies and fungi on tree roots, followed 

by a discussion of evidence that 

ectomycorrhizal fungi differ in their abilities 

to take up water and nutrients - both in pure 

culture and in association with tree roots. 

'presented at the Symposium on "current Topics 

in Forest Research: Emphasis on Contributions 

by Women ~cientists", U. S. Forest Service 

Southeastern Forest Experiment Station, 

Unfversity of Florida, Gainesville FL, 4-6 

November 1986. 

'~esearch Professor, College of Forest 

Resources AR-10, University of Washington, 

Seattle, WA 98195. 

Abstract A fascinating paradox is the low 

species diversity of trees in the Pacific 

Sorthwest and the high species diversity of 

associated ectomycorrhizal fungi. This paradox 

suggests that the fungal diversitv may arise 

from a physiological specialization for nutrient 

and water uptake, which will benefit the host 

trees. This paper describes research to support 

this hypothesis. 

Keywords: Ectomycorrhizae, fungi, conifers, 

water stress, nitrogen uptake, phosphorus 

uptake. 

LINKAGES BETWEEN FRUIT BODIES AND 

ROOT-ASSOCIATED FUNGI 

Fruiting of Ectomvcorrhizal Fungi 

Fruiting Patterns 

Sporocarps (fruit bodies) of ectomycorrhizal 

fungi are a dominant diverse feature of the 

forest floor and litter in many coniferous 

forests. An estimated 43% of the above-ground 

(epigeous) sporocarps in a Scots pine 

plantation were ectomycorrhizal; the remaining 

species were saprobic fungi (Richardson 1970). 

In Pacific silver fir stands in western 

Washington, USA, 50-85% of the epigeous 

sporocarps were ectomycorrhizal (Vogt et al. 

1981). Observations on probable mycorrhizal 

fungi and lists of general occurrence have been 

made by numerous researchers (Trappe 1962 and 

papers cited therein; Ammirati et 5 1981; 

Knighton 1976; Rhoades 1972; Maas and Stuntz 

1970). In some Douglas-fir forests, there may 

be more than 300-400 different ectomycorrhizal 

fungal species, but we know of no studies which 

have systematically surveyed these forests 

(Ammirati pers. comm.). In addition, hypogeous 

fungi are often neglected. 

Importance of Hypogeous Fungi 

Ectomycorrhizal fungi may fruit above-ground 

(epigeous) or below-ground (hypogeous, 

truffles) or they may not fruit at all. 

Hypogeous species, although they are not 

readily visible, are abundant and are often 

mycorrhizal (Fogel 1981, Vogt et al. 1981). 

The Pacific Northwest forests "harbour more 

known truffles species than any comparable area 

on earth.. . .'I (Trappe 1980). 

In Oregon, 24 different below-ground species 

were found in a young Douglas-fir stand (Fogel 

1976, 1981). Similar numbers were reported in 

an Italian oak stand, a German red beach 

forest, and a German spruce stand (Ceruti et - al. 1967, Gross 1969). Productivity of 

hypogeous fungi is impressive - up to 16,700 

sporocarps per hectare in a western Oregon 

Douglas-fir forest, with optimal production 

located about mid-way between any 2 tree stems 

(Fogel 1976). 
Fruit Body-Root Connections 

Thus far we have been discussing only the 

fruit bodies. How are fruit bodies related to 

ectomycorrhizal fungi on roots? 

Ectomycorrhizal species are generally assumed 

to be functioning in a forest ecosystem if 

their fruit bodies are present. However, this 

assumption lacks supportive evidence and needs 

careful evaluation. "Our knowledge of most 

higher fungi is so very meager at the moment 

because our results are dependent entirely on 

observing fruit-bodies and these are only a 

small part of the actual fungus ....I1 (Watling 

1974, p. 231). 

The ectomycorrhizal fungus complex consists 

of fruit bodies attached to hyphae in the 

litterlsoil matrix and of fungal hyphae on the 

roots. The major functioning part of the 

complex is the ectomvcorrhizal hyphae on the 

roots. However, most physiological studies have 

been conducted with fungi isolated from 

sporocarps. 

Identification of Ectomvcorrhizal Funei 

Fruit Bodies 

Identification of ectomycorrhizal fungi is 

based entirely on the fruit body - using a 

variety of characters such as color of spores 

and the fruit body (mushroom cap and stalk), 

presence of gills or pores, microscopic 

examination of hyphal structures, etc. Even 

with the presence of a fruit body, often 

identification can be difficult (Ammirati pers. 

comrn.). 

Root-Associated Fungi 

Isolation and Identification Difficulties. 

Fungi are difficult to isolate from roots, in 

contrast to the relative ease of isolation from 

mushroom sporocarps (Zak 1969, 1973; Molina 

and Palmer 1982). Further, root-associated 

fungi are difficult to identify since they do 

not produce sporocarps in pure culture. Thus 

although it is important to work with 

ectomycorrhizal fungi known to be associated 

with roots, little work of this kind has been 

done due to difficulties of isolation, culture 

and identification. 

Methods of Identification. By detailed 

morphological studies of roots ectornycorrhizal 

with a single, known fungal species, one can 

learn to identify certain fungi with reasonable 

success. Using characteristics of gross root 

morphology, degree of root branching, thickness 

and color of hyphal sheath, length and diameter 

of hyphae, etc., Last and co-workers could 

distinguish 3 different ectomycorrhizal types 

on tree roots (Last g al. 1985). 

Detailed studies of ectomycorrhizal root 

morphology are being done by Agerer (Agerer 

1987). In some cases, electron microscopy has 

been used to study ectomycorrhizae (Strullu 

1976). Ascomvcete hyphae (simple septa) can be 

distinguished from Basidiomvcete (dolipore 

septa) (Scannerini and Bonf ante-Fasolo 1983) . Several researchers have tried to identify 

fungal hyphae on the basis of species-specific 

monoclonal antibodies - but with limited 

success (Schmidt et al. 1974; Chard 1981; 

Wright and Morton, W. VA Univ., pers. comm.). 

In our laboratory we are using DNA 

restriction enzyme patterns to identify these 

ectomycorrhizal fungi. The DNA methodology 

involves growing fungi in pure culture and 

harvesting after several weeks. We are trying 

several different protocols for DNA extraction 

which involve a CTAB extraction followed by 

cesium chloride density gradient 

centrifugations. When the DNA is sufficiently 

clean, restriction enzymes are used to cut the 

DNA, followed by Southern blots, using a veast 

ribosomal probe. We have had some success with 

several fungal species - Boletus edulis, 

Laccaria laccata, and Hebeloma crustuliniforme. 

Regardless of the methods chosen, it is 

clearly important to be able to identify fungi 

on roots. Then we can begin to understand 

fungal succession on roots and to study the 

different physiological functions of these 

fungi . 

ECOPHYSIOLOGICAL DIVERSITY 

Tree growth is often limited by water stress 

and nutrient availability, particularly 

phosphorus and nitrogen. Since nutrients and 

water enter the tree primarily through 

mycorrhizal roots, it is likely that these 

fungi can exert major controls on these 

processes. We know that mycorrhizae generally 

enhance water and nutrient uptake, but little 

is known about how individual fungal species 

differ with respect to these processes. The 

following sections discuss the ecophysiological 

diversity of ectomvcorrhizal fungal species for 

water and nutrients. 

Water Stress 

Mycorrhizal associations can increase 

transpiration flux and the ability to tolerate 

water stress in their host trees. These 

benefits may result from several fungal 

effects. First, fungi explore a greater soil 

volume, taking up more water. Secondly, fungi 

improve the nutritional status of the host, 

thus optimizing the whole plant's physiology 

and its water status. Thirdly, some fungi 

produce rhizomorphs (root like hyphal strands) 

which are specialized for rapid water transfer 

through the hyphae. Fourth, the hyphal system 

has a capacitance for water storage, increasing 

the amount of water available to the host. 

What is the experimental evidence to 

substantiate these four suggestions? 

Although most work has been done with 

endomycorrhizae, the more limited work with 
ectompcorrhizae does support the hvpothesis that 

mycorrhizae increase water movement through the 

host (Ekwebelam and Reid 1983; Parke et al. 

1983; Dixon -- et al. 1980; Reid 1979). 

Ectomycorrhizal roots can survive greater soil 

moisture depletion than nonmgcorrhizal roots, 

perhaps due to the fungal abilitv to tolerate 

greater water stress levels than those tolerated 

by plant roots (Cromer 1935; Goss 1960). If 

fungi can influence the host water status, what 

ecophysiological diversity exists among 

different fungal strains? 

In pure culture, using polyethylene glycol 

(PEG) to induce osmotic stress, the fungus 

Cenococcum geophilum seems to be very tolerant 

of low water potentials, unlike such fungi as 

Suillus luteus and Telephora terrestris (MexaL 

and Reid 1973). This fungus can survive Low 

water potentials in the field as well (Pigott 

1982). Two different fungi, Rhizopogon 

vinicolor and Pisolithus tinctorius, also differ 

in their response to PEG-imposed water stress 

(Dieblot and Mudge 1985). 

We have collected data for a number of species 

and found a wide range in fungal growth response 

to PEG-imposed water stress in pure culture 

Fig. 1 These diameter growth data represent 

3 patterns of response to stress. Type 1 

represents fungi which exhibits tolerance to 

stress, since the fungi can grow better under 

moderate stress (-3 or -7 bars) than under 

little (-2 bars) stress. Tvpe 2 fungi have an 

intermediate response with progressive 

inhibition of growth as osmotic stress 

increases. Type 3 fungi show total inhibition 

of growth under anv osmotic stress at all. In 

our current work, we have found another pattern, 

which suggests that some fungal species map be 

able to develop stress tolerance (M. Coleman, 

pers. comm.). These fungi initially grow 

poorly under imposed stress, but adapt over time 

and grow more rapidly. 

Figure 1. Diameter growth in mm of 3 types of 

ectomycorrhizal fungi grown for 30 davs in 

liquid culture of varying osmotic stress from -1 

to -30 bars (Fig. 1) 

30 

TYPE 1 TYPE 3 

Negative Osmotic Potential, bars 

An important step in evaluation of the range 

of responses of fungi to water stress is an 

examination of these fungi when in association 

with tree seedlings, We are proceeding to 

svnthesize mycorrhizal seedlings with these 

osmotic-stress tolerant and intolerant 

seedlings to determine if the fungal attributes 

are passed on to the host. Similar work is 

being done bv Xudge at Cornell KY (pers, 

corn..). In some other seedling work, Parke 5 

- 

al. 1983 have shown that some fungal specLes 

apparentlv allow seedlings to recover faster 

from drought stress. 

Nutrient Uptake 

Ectomycorrhizal fungi clearly benefit the 

nutrition of their hosts, particularly for 

nitrogen and phosphorus. We believe that some 

fungi are better than others at uptake of K and 

P, Further, this enhancement should increase 

nutrient levels in the tree, 

Phosphorus 

Fungi take up and store inorganic P (and 

perhaps organic P), but most fungal data in 

pure culture are for nonmycorrhizal fungi 

(Beever and Burns 5980). 

in our current work, we are screening a 

number of different ectomycorrhizal fungi for 

their ability to take up inorganic phosphate. 

Preliminary results indicate that these fungi 

do differ in their phosphorus uptake rates 

(Brown, unpublished data). 

Far ectomycorrhizal roots, Langiois and 

Fortin (1984) reported differences in rates of 

P absorption between different color types of 

ectomycorrhizal roots, The absorption of 

golden ectomycorrhizal apices was much higher 

than that of the 3 other types throughout the 

season (Langlois and Fortin 1984). 

There are also differences in phosphatase 

activities of a number of different fungi 

(Antibus -- et al. 1381; Wo and Zak 1979; 

Calleja and D'Auzac 1983)- Phosphatase 

activity may or may not be related to P levels 

Ln the surrounding medium; data are 

conflicting (Calleja and D%uzac 1983; Dighton 

1983; Zacaze 1983; Doumas et al. 1980; 

Alexander and Wardv 1981), Clearly much more 

research on the functions of the varlous 

phophatases is needed, In general, however, it 

seems likely that fungi do differ 

physiologically in their ability to take up 

phosphorus. 

Nitrogen 

Inorganic Nitrogen, Mycorrhizae can enhance 

uptake of inorganic N by trees o ow en and Smith 

1981; France and Reid 1978; Littke 1982; 

Rygiewicz et ale 1984a and 1984b). Fungal 

species grown in pure culture differed in their 

rates of amoniurn uptake (LFttke et ale 1984). 

The most rapid rates (Pisolithus tinctorius) 
were 600 micromoles per gram dry weight roots 

per hour, 3 times greater than the lowest 

rates, observed in a strain of Bebeloma 

crustuliniforme, 

The genus of the host also affected N uptake 

since uptake rates of Douglas-fir mycorrhizal 

with Hebeloma were higher than were uptake 

rates for western hemlock mycorrhizal with the 

same fungus (Rygiewicz et & 1984a). 

Mycorrhizal fungi map also be able not only 

to increase nitropen uptake but also to shift 

the pH optimum for ammonium uptake (Rygiewicz 

-- et al. 1984a) and alter ionic balance during 

ammonium uptake (Bledsoe and Rygiewicz 1986). 

Organic Nitrogen. Soluble orpanic N exists 

in many soils in ecologically significant 

concentrations. Mycorrhizal roots may be able 

to take up this form of N as well as the 

inorganic forms of ammonium and nitrate. We 

have studied the abilities of different 

ectomycorrhizal fungi to take up organic N in 

the form of amino acids (Bledsoe and Sangwanit, 

unpublished data). Our data suggest that the 

choice of the fungal partner can affect the 

amino acid uptake rate. Further, the 

mycorrhizal roots seem to store more amino 

acids in the roots, while nonmycorrhizal roots 

transfer more N to their shoots (Sangwanit and 

Rledsoe, unpublished data). All the above data 

support the hypothesis that there are 

differences in the ability of ectomvcorrhizal 

fungal species to take up N and these 

differences may affect the nutrition of the 

host. 

Since mycorrhizal roots are the principal 

means by which trees communicate with the soil 

environment, understanding this linkage is 

necessary to the study of how forests function. 

We wil.1 contribute to this understanding by 

learning how ectomycorrhizal fungi differ 

functionally. This knowledge may help to 

explain why certain fungi do not survive when 

outplanted cnly dry, nutrient stressed sites 

(Bledsoe et al. 1982). In addition, 

identification of specialized fungal species 

map allow selection of fungi to enhance tree 

seedling growth on these stressed sites. 

ACKNOWLEDGEMENT 

The author thanks Mark Coleman, Uthaiwan 

Sangwanit and Douglas Brown for discussions of 

their unpublished data. This study was 

supported by NSF grants BSR-830501 and 

BSR-8510858 and USFS Cooperative Aid grant 

PNW-83-222. 

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Stand Dynamics and Early Growth of Yellow Birch 

and Associates in the White Mountains 

1 

Deborah B, ~i%l" 

Yellow birch is usually regarded as one of 

the more valuzble commercial species sf the 

northern hardwood forest, Today in northern 

New England, it still ranks third as veneer 

logs and fourth in sawlog value, Historically, 

it has averaged between 50 and 20 percent of 

the northern hardwood association, but In 

recent decades, yellow birch has been observed 

to be closer to the lower end of that range and 

its proportion in younger age classes indicates 

further decline in numbers, 

Generally, sugar maple and heech appear to be 

distributed throughout old growth and second 

growth northern hardwood stands. Birch, on the 

other hand, is located primarily along streams 

or in other moist sites {HoyLe 1965, Kujawski 

and Lemon 1969), Near the periphery of its 

range, yellow birch is Found almost exclusively 

on very wet sites, It is hypothesized that 

yellow birch is able to compete more 

successfully on wetter sites that are less 

desirable for other species, but is unable to 

compete aggressively with sugar maple and heech 

on the generally most desirable mesic sites. 

Historical Logging practices and 

silvicultural experimentation have shown that 

shade tolerant species, such as sugar maple and 

beech, regenerate cutover areas best when they 

occur in the understosy as advance growth, 

Yellow birch, on the other hand, being 

moderately shade intolerant, regenerates best 

 fro^ seed an newly cut areas where there is 

both adequate light and disturbed seedbed 

conditons, Because its shade tolerance is only 

moderate, yellow birch does not usually 

regenerate successfully under a closed canopy, 

'presented at the Current Trends in Forest 

Research, Society of American Foresters 

meeting, Cainesvilhe, Florida, 

2~ssistant Professor, Department of Forestry, 

University of Kentucky, Lexington, KY 40546- 

0073. 

Abstract,--In the beech-birch-maple association 

within the northern hardwood forest type, 

American beech i Ehrh. and 

.) have been 

rninate yellow birch (Betula 

Britt.) in frequency, abundance, 

density, and size, However, under conditions 

of heavy removal cutting on the typically moist 

but well-drained till soils of the northern 

hardwood type, yellow birch demonstrates 

aggressive growth in all these parameters in 

comparison with heech and sugar maple. 

Keywords: Northern hardwoods, soil moisture, 

stand dynamics, yellow birch 

The history of forest management in the White 

Mountains consisted primarily of logging for 

softwood timber in the late nineteenth and 

early twentieth centuries, followed within a 

Pew years by equally heavy harvesting of :he 

more valuable hardwoods, such as the birches 

and sugar maple. This kind of selective 

cutting, otherwise known as high-grading, had a 

negative effect on the residual stands because 

they were then heavily dominated by beech of 

varying quality and by poor-quality specimens 

of a variety of other species. 

The style of cutting done in the early 

decades of' the twentieth century left many 

forested areas with old growth that was 

unmerchantable, and incoming growth of 

predominantly shade tolerant species. Without 

sufficient openings in the canopy, young yellow 

birch simply did not replace itself in numbers 

sufficient to maintain a moderate proportion in 

the stands, Oceasionally, nearly pure yellow 

birch stands can be seen as the result of a 

major perturbation such as a hurricane blowdown 

or a fire, Silvicultural practices which 

provide larger openings than single tree 

removal are therefore probably more desirable 

for the encouragement of yellow birch 

proliferation in subsequent stands. 

Many studies have been done to clarify the 

best conditions under which yellow birch will 

germinate and establish seedlings. The main 

purpose sf this study was to examine the 

dynamics of growth between yellow birch and its 

competing associates in the sapling and polesize stages of stand development. The question 

was whether or not yellow birch could compete 

aggressively with its associates, as well as 

what effect soil moisture had both on the 

development of all three species, and on their 

interactions. 

The objectives of this study were: 

First - to determine whether, under what 

conditions, and by what sequence of events, 

yellow birch might outcompete or gain 

ascendancy over sugar maple and beech after 

group selection or patch clearcutting 

harvesting practices. 
Second - to determine the effect of soil 

moisture variations on the interaction 

between sugar maple, beech, and yeblow birch, 

within the range of sites suitable for sugar 

mapie and other characterisitlc northern 

hardwood speeles. 

And - to determine whether or not 

yellow birches initiating from seed after 

cutting could compete su@eessfully with 

advance growth seedlings or saplings of sugar 

maple and beech in their first decade or so 

of growth, 

The primary study area was located on the 

Bastlett Experimental Forest in Bartbett, New 

Hampshire just northwest of' the Presidential 

Range of the White Mountains in the White 

Mountain National Forest, The Bartlett Forest 

has been devoted to silvieuLtura1 research 

since the 19308ss. An experiment had been 

initiated there in the late 30Ps and early 40fs 

to increase the proportion of yellow birch in 

the hardwood stands by clearcutting a series of 

small patches (-10--30 ha). These thirty-odd 

patehes were scattered over a 40-hectare area 

with the expectation that new areas would be 

opened up on a 20-year cycle, so that 

ultimately the entire 40 beetares would be a 

mosaic of small, evenaged stands. Two 

additional sets of' elearcuts, each comprising 

about 18% of the area, were made in 1950 and in 

1960, but no further cutting has been done' 

since. Soils are primarily spodosols of 

glacial origin varying in texture. Aspects are 

northerly varying from ENE do WNW and 

elevations range from 372-4532 ZI (m*s.l.), As a 

result of the northerly orientation, none of 

these sites were "dryw in an absolute sense: 

some were relatively drier than others. 

Secondary study areas at the Hubbard Brook 

Forest in West Thornton, Mew Hampshire and at 

Sawyer River in Livermore, New Hampshire were selected because they also supported northern 

hardwood forest associations and had had 

comparable histories or logging, Hubbard 

Brook" second growth forests were 55 to 58 

years old; Sawer River had been cut in the 

1950Fs and supported a 15-20 year old forest. 

Both sites were similar to BartLett in slopes 

and elevaticns; Sawer River also had a 

northeasterly orientation; Hubbard Brook faced 

soukh (Tabbe 1)- 

To determine moisture variability on the 

Bartlett sites, an attempt was made to locate 

the water table, or at least the capillary 

zone, with a soil auger in each of the patches, 

This was successful in 12 of the 30 patches; in 

the remaining patches, the water table or its 

capillary fringe was not reached, and moisture 

tension was measured with a tensiometer, Where 

the water table had been located, narrow wells 

were dug with a tile spade to a depth of 

roughly 68 crn for the purpose of monitoring the 

fluctuation of the water table throughout the 

growing season, The wells were monitored at 

Least once a week throughout the two rowing 

seasons of the study, Permanent 25 m 5 plots 

sites were chosen where the wells were located 

at BarLett, and additional sets of 12 25 rn2 

plots were established at the two secondary 

sites during the se~0nd growing season of this 

study. Moisture availability at the secondary 

sites was determined with a tensiometer 

calibrated according to the known moisture 

bevels on the well sites at BartEett, 

Slope, aspect and elevation were determined 

for all plots, Frequency of yellow birch, 

beech and sugar maple was determined, as well 

as density, abundance, and importance value, 

Soils were sampled and identified- Basic 

weather data jrnax,/min, temperature, rainfall) 

were recorded at Eartlett for both growing 

seasons and correlated with well data. Weight 

and diameter measurements were taken on all 

experimental trees and pairs 0% increment sores 

were taken from each tree for aging, 

Owing to the variability oP growth parameters 

resulting from suppression of trees during 

stand development, it was decided to limit the 

majority of the analyses to those trees of each 

species which had been most successful in terms 

sf total. attained height, All tree data on 

each plot were scrutinized, the tallest beech, 

yellow birch, and sugar maple were chosen from 

those prese2t, and up to three additional trees 

of each species were selected from a roughly 

comparable height class within each plotThese subsets were then utilized for the 

detailed data analyses, In addition, 29 

dominant trees of each species, located near 

but not within plot boundaries at Bartlett, 

were harvested for stem analysis and sectioned 

at metes intervals, An attempt was made to 

select these tsees from areas with varying 

moisture availability, but ultimately they all 

ended up in the wettest range as determined by 

tensiometer readings, 
All tree data were subjected to standard 

statistical methods. Multiple linear regression 

and stepwise multiple regression analyses were 

run for the tallest trees of each of the three 

major species on all sites. Student" t tests 

were performed on comparison of most growth 

parameters between tallest trees or all trees 

of pairs of species on all plots. 

Results 

A11 of the observations of this study were 

confined to moist but well-drained glacial till 

soils. Within this stated range of sites, an 

attempt was made to include the widest possible 

range of soil-moisture conditions. During the 

course of the study it became apparent that the 

actual range of soil moisture was remarkably 

small. While soils derived from the rocky 

tills of the region are highly variable, the 

actual range of soil moisture was very small 

compared to that of forest soils in general. 

The three areas used in this study varied 

primarily in age. At Bartlett, age determined 

from cores and discs indicated that beech and 

sugar maple were often present as advance 

growth, while yellow birch usually came in from 

seed after logging. The age range within the 

plots was narrow enough to consider them 

evenaged, and about 35 years old. Topography 

varied from knolls and slopes of varying 

steepness to flat or concave areas. Most of 

the plots were on typical moist but welldrained soils. 

The site at Hubbard Brook was quite damp, 

with proliferation of ephemeral streams common 

after heavy rains. At Hubbard Brook, there 

were really two age classes, but most of the 

trees were between 55 and 70 years old. The 

tallest trees used for data analysis were 

primarily from the older age class. 

Table 2.--Freqitency of oecurr~ni~t~, 

of yellow blrch, beech, and sugir 

At Sawyer River, information from the aging 

of cores and discs showed that the beeches 

frequently originated from advance growth; 

occasionally the sugar maples did also, but the 

majority of trees of all species at that 

location came in from seed or from seedling 

sprouts present at the time of the clearcut 

approximately 20 years before this study. 

The original hypothesis of this study was 

that yellow birch was better adapted than beech 

or sugar maple to utilize moister sites, and 

was thus expected to: 1) occur with great 

frequency, abundance, and density; 2) be more 

sueeessful in competition with sugar maple and 

beech; and 3) demonstrate better growth than 

the other two species or than itself on drier 

sites, as measured by parameters such as 

height, diameter, and volume. 

Percentages of frequency, abundance and 

density were calculated from measurements on 

all trees of the three species studied on all 

plots. Importance value is derived form the 

sum of the other three parameters. Table 2 

illustrates that yellow birch is often 

significantly greater in abundance, basal area 

and importance value than either or both sugar 

maple and beech on the wettest sites. Its 

dominance diminishes as the sites become 

relatively drier. 

Height and diameter measurements were taken 

for all dominant study trees in each plot. 

Figures 2 and 3 illustrate that yellow birch is 

again greater in both height and diameter than 

the other two species on these 

characteristically damp sites. Sugar maple and 

beech show increases in both height and 

diameter with increasing dryness, but do not 

exceed the performance of yellow birch. 

abiind?nc:e, basal area 'pet) , and importance valile 

rn3pie by molstiirp tr:r?ion range and stand age. 

Moi?t,ilr~ Tension {i Plots PcL Frrqil~ncy Pct Ablir,~lince Pet Bas.il Area Importance Value 

Ic~~nt i5ar-3) YR 34 Re 'I!!? 34 Be "3 SM Be YB SM 13e 

00-10 (wet) 12 83 i0? 9? 25 2 23 ;gab' 9 15" 4 1.33 1.30 

35 years 

00-10 (wettest) 1 8 100 83 86 36ab 27 22 47a5 18c 9 1.83ab 1.23ab 1.17 

11-20 7 100 57 100 32a 23 31e 314" 16 23 i.66" 0.93 1.5he 

21-40 (driest) 5 100 83 100 ?ha 13 35" 323b 17 14 1.60"~ 0.90 1.49 

60 years 

00-10 (wettest) 3 100 75 75 91b 41 12 65b 22 2 2.06b 1.38 0.89 

1 i-20 6 100 88 63 31 38 22 52"3c 9 1.83~ 7.60 0.94 

21-40 (driest) 2 ?00 100 100 25 37d 30 54b 4Oc 3 1.79 1 .7TC 1-36 

'a11 letters indicate d~fferenc-3 at; signrficance levels of 90 pct or- greater. 

a = yellow brrch > sitgar maple 

b = yellow bxch ) beech 

c = sugar maple besch 

d = silgar maple yellow birch 

e = beech .* sugar maple 
* - 0 - 0 

-a > 

2 z 

V 

z 2 ai cn E ' 

2 $ 

wt- 

; z w 2 

4 ,. 

Legend 

tl Yellow Birch ' Cl SIJ~OS Maple 

&?Z4 Beech 

Fig. 2 Mean Diameter (cm) Per Plot for Yellow 

B~rch, Sugar Mople and Beech By 

Age and Mo~sture Tension 

35 Yrs 

Stand Age iyrs) and Motslure Tens~on (centibars) 

Legend 

nYellow Btrch 

a Sugar Maple 

e8kd]lBeech 

FI~ 3 Mean Her~ht (M) Per Plot for Yellow 

B~rch. Sugor Mople and Beech by 

Age and Mo~sture Tension 

-- - 

00-10 00-10 11-20 21-40 00-10 11-20 21-40 

Stand Age lyrs) and Moisture Tens~on (cent~bors) 

Volume index (m/3) is a parameter derived 

from the product of height (m) and basal areas 

(m2) of each tree within the experimental 

plots. Volume index values are an 

approximation of relative stem volume, not of 

actual volume (Table 3). Figure 4 shows that 

species other than sugar maple, beech, or 

yellow birch were more important components of 

the total volume in the younger stands, but 

less so in the oldest stands, particularly on 

the most mesic sites. Beech is a small 

component of all stands relative to sugar maple 

and yellow birch, but the three species 

together clearly comprise more than threequarters of the total volume of these areas. 

Differences among the three species are 

generally most significant on the wettest 

sites, although on the 35-year-old stand, 

yellow birch dominates sugar maple 

significantly at all moisture levels. 

Fig 4. Mean Volume Index Per Plot fur Yellow Birch. 

Sugor Maple, Beech, and Other Spec~es 

By age and Mossture Tension 

Legend 

Yellow Birch 

r;9 01 her Species 

20 Yrs 35 Yrs 60 Y rs 

Stand Age (yrs) and Moisture Tension (cent~bars) 

Table 3.--Mean volllme lndexl and percentages per plot 

for yellow blrch, sugar maple, beech, and all specles 

Mornt:~re Tension # Plots YB SM Be All Species 

20 years 

00-10 (wettest) 1 2 1.44ab (33 pct) 0.27C 16 pet) 0.47 (11 pet) 4.42 (100 pet) 

35 years 

00-10 (wettest) 18 6.16ab (48 pet) 2.30C (19 pet) 3.52 (4 pet) 12.74 !I00 pet) 

1 1-20 7 3.5Za (34 pet! 1.84 (18 pet) 2.56 (25 pet) 10.22 (100 pet) 

21-40 5 4.6~ (34 2.02 (15 pet) 1.75 (13 pet) 13.70 (100 pet) (driest) 

60 years 

00-10 (wettest) 3 19.83a"(h11 pet) 14.72" (73 pet) 0.33 (1 pet) 30.87 (100 pet) 

1 1-20 6 14.01ab (6; pc" 6.53c (29 pet) 1.72 (8 pet) 22.48 (100 pet) 

2 1-110 i driest 1 3 21.12 (60 pet) '3.14C 137 pet) 9.85 (2 pet) 35.12 (100 pet) 

lvoliias index (&) = basal area (m2) x total height (m) 
Rate of height growth was determined in two 

ways: first by dividing the height of tallest 

trees of each species by their ages as 

determined from increment cores, and second by 

stem analysis of the tall trees from the 

Bartlett plots, Data Prom the larger group of 

trees (Figure 5) show that yellow bireh usually 

has a more rapid rate sf growth than the other 

two species, and consistently shows a greater 

advantage on the wettest of the sides, 

Fig 5 Rate @"eight Gr,wle i F4 i for 'reiiciv, BircO Sugor Maple, sna Beech By Age and Morsiure Tensicn 

t3 V1 

- 0.5 - ru 

!? g 

2: 4 - * 0 e 

2 z g6- 3 

- - M 

g 2 2 €= b 

a- * 0 em25 ' w - -a 3. 

0 20 Yrs 35Yrs 60 Yrs 

00-10 00-LO 11- 20 21-40 CO-I0 11-29 21-40 

Stand Age (yrsi and Marslure Tension (centtborsl 

The smaller sample of 29 tali trees from 

Bartlett yielded results similar to those sf 

the larger sample (Figure 61, What is most 

interesting in this wore detailed analysis is 

that the yellow bi~ehes began later, andlor had 

achieved Less height growth at the first point 

(1940) than the sugar maples and the beeches. 

But within ten years, the birches had taken 

dominance and maintained that dominance over 

the other two species for the subsequent 15 

years- A measurement sf the three harvested 

trees - one of each species - in one plot also 

shotis the performance of yellow bireh coming 

into the stand well after &he adher two species 

and still being able to achieve parity with, if 

not dominance over, the other species (Figure 

7) 0 

C3 YsIlo+r Ealrch I'si low B~rch, Suglrr Mdplr and 

TS1 Sugar Maple Bac-ck on 

lfBlB Beech 39 Yr -Old Wicir~f Srtes 

15 

Fiq 7 Comparative Cnn.ioi Wciqnr i3roivrn (M: 

2 I r Leaend of 'rellow Ejlrch, Sugrir Maple, and Beech on Gna P:ot at hiahest PJetfiure I Vci*Soa birch -- Content 

Beech ...... 

Data from tallest trees was analyzed by both 

multiple binear regression and stepwise 

multiple regression, A11 three species and 

experimental areas were analyzed separately. 

Final analysis plotted height against site 

factors and age bud did not yield high 

values, The trends indicate that yellow birch 

height varies with factors associated 

with reduction in moisture availability; sugar 

maple and beech appear to vary with 

the same site factors, Regression analysis 

served to corroborate that inherent differences 

in height growth between species were much more 

important khan those within or between species 

induced by soil variables in the observed 

range, 

DISCUSSION 

Results of the various experiments performed 

in this study show similar patterns, En the 

forest, under conditions of group selection or 

patch elearcutding, yellow bireh comes in with 

greater frequency, abundance, and density than 

either sugar mapbe or beech. Mithin the 

typical northern hardwood range, the wetter the 

cut-over sites are, the more consistently 

dominant yellow birch is in the stands, as 

measured in growth parameters such as height, 

diameter, and volume, and the greater ability 

yellow bireh has to compete sueeessfully with, 

and often supercede, the height growth of the 

other two species, regardless of the others? 

initial height advankage, If all three speeies 

originate simultaneously on these moist but 

well-drained nostkern hardwood sites after 

heavy cutting, yellow birek will probably 

dominate because of its rapid early height 

growth- If smar maple and beech occur as 

advance regeneration, yellow birch still 

frequently can competc with, or exceed, the 

growth of the other two, but the probability sf 

yellow bireh dominating is less certain, 

Information from statistical analyses of 

trees on the experimental plots, and from stem 

analyses of harvested trees near the Time 
experimental plots at Bartlett, Tndicates that 

the relative rate of height growth of yellow 

birch, particularly in the first couple of 

decades of development, is significantly 

greater than the rates either for sugar maple 

or for beeeh. 

Yellow birch thus appears to be at a 

selective and competitive advantage on the 

moister sites of the northern hardwood type 

range, in comparison with sugar maple and 

beech. The fact that yellow birch is a 

profligate water user with a consequent high 

moisture demand, compared with sugar maple and 

beech, may account in part for the observed 

differences in growth behavior among the three 

species on the moist sites. 

CONCLUSIONS 

The range of yellow birch is broad, extending 

from the Atlantic coasts of the United States 

and Canada west to the Lake States and south 

into Georgia along the Appalachian Mountain 

range. Other studies indicate that yellow 

birch has both genetic and morphological 

variability over its range (Clausen 1968, 4973; 

Fowells 1965; Sharik and Barnes 1979, Wearstler 

and Barnes, 1977). The results of this study 

are therefore clearly restricted to the forest 

types I observed - the beech-birch-maple 

association of northern hardwoods found on 

typically moist but well-drained podzolic 

soils, subjected to clearcutting in patches or 

group selection cutting. These results are 

probably applicable therefore only in the 

northeastern United States and possibly eastern 

Canada. 

Most of the data presented in this study show 

that yellow birch outgrows both sugar maple and 

beech, and often all other species, on the 

experimental areas. The question arises why 

there is not more yellow birch in the oldgrowth and second-growth forests of northern 

New England. The answer probably lies more in 

the history of logging practices than in the 

suitability of the sites. In the undisturbed 

forest, the most frequent cause of openings for 

new growth is the demise and subsequent 

windthrow of individual trees. Though such 

relatively small openings in the canopy do 

provide sufficient light for the moderately 

shade tolerant yellow birch to germinate and 

grow, the small space is usually rapidly 

utilized by existing codominant trees or 

smaller growth near the opening, and by 

aggressive advance growth of the more shade 

tolerant sugar maple and beech. Only large 

scale natural catastrophes, such as hurricane 

or fire, open areas sufficiently large to 

encourage yellow birch regeneration. Openings 

larger than a hectare, particularly after fire, 

were more conducive to invasion by paper birch 

than by yellow birch, so storm-induced 

windthrow pockets provided the most 

advantageous conditons for the establishment of 

yellow bireh as a substantial. proportion of the 

stand, 

Early logging practices in the White 

Mountains of highgrading, or selecting out the 

best and biggest trees, were to a large extent 

mimicking the single tree openings in the 

natural forest, and as such, were more 

favorable to beech and maple than to yellow 

birch establishment, It is the more recent 

practices of group selection cutting (which 

Leaves a minimal canopy), an3 elearcutting, 

either in large units or in smaller strips and 

patches, that have simultaneously provided the 

eonditons of adequate light and adequate 

moisture, both necessary for the successful 

establishment of yellow bireh. k side effect 

of clearcutting is that the water tables are 

higher after the transpiration pump of the 

forest is removed, Extensive studies (Marquis 

1965~1, 1965b, 1966, 1972, Hatcher 1966, Filip 

1973, Esdmann et al, 1381, Roberge 1975) have 

shown that the scrip and patch eleareutting are 

most advaa tageous to the germination, 

establishment, and early growth of yellow 

bireh, The history of the three areas used in 

this study included periodic heavy cutting at 

Hubbard Brook, patch elearcutting at Bartlett, 

and extensive elearcutting at Sawyer River, 

The results of this study show that suck 

cutting practices enhance the growth of yellow 

birch relative to sugar maple and beeeh in the 

sapling, pole-size, and Later postestablishment stages, 

The height growth of yellow bireh does not 

vary widely throughout the range of moist sites 

typical of the northern hardwood forest type. 

The height growth of sugar maple and beech is 

far more sensitive to the wetter end of this 

range and shows increasing improvement as the 

sites become more mesic, Both sugar maple and 

yellow birch tend to dominate beeeh, unless 

beeeh occupied the s i t e f i r s t as tall advance 

growth prior to logging, Since the wettest of 

the northern hardwood sites are more favorable 

to yellow birch than to the other two species, 

yellow bireh can quickly gain ascendancy over 

the others, both in height and in numbers of 

trees. However, as the sites become drier, the 

dominance of yellow birch over sugar maple is 

Less certain, though its dominance over beech 

remains fairly consistent, 

The importance of certain cutting practices, 

such as patch eleareutting, for the success of 

yellow birch has been well established. The 

results of this study--in frequency, abundance, 

and density; in competitive ability; in 

parameters of height and diameter,--support 

previous work and show that yellow birch grows 

consistently more aggressively and successfully 

on those sites with abundant moisture khan do 

either sugar maple or beech, Since soil 

moisture conditons can be readily ascertained, 

it is hoped that future yellow birch management 

will select areas for cutting with the moisture 

conditions of the regenerative site in mind, 
Selecting the moister sites could insure a more 

vigorous and reliable crop of yellow birch than 

would be found on the more mesic sites of the 

northern hardwood type, where sugar maple and 

beech are likely to be more competitive. 

LITERATURE CITED 

Clausen, K. E. Natural variation in catkin and 

fruit characteristics of yellow birch. 15th 

Northeastern Forest Tree Improvement 

Conference Proceedings 1967. 1968. pp. 

2-7. 

. Genetics of yellow birch. 

U.S. Department of Agriculture Forest Service 

Research Paper. WO-18. 1973. 

Erdmann, Gayne G., Ralph M. Peterson, Jr. and 

Richard M. Godman. Cleaning yellow birch 

seedling stands to increase survival, growth, 

and crown development. Canadian Journal of 

Forest Research. 1981. 11(1):62-68. 

Filip, Stanley M. Cutting and cultural methods 

for managing northern hardwoods in the 

Northeastern United States. U.S. Forest 

Service General Technical Report. NE-5. 

1973. 7 PP* 

Fowells, H. A. (Editor). Silvics of forest 

trees of the United States. USDA Handbook 

No. 271. 1965. 

Hannah, Peter R. Crop tree thinning increases 

availability of soil water to small yellow 

birch poles. Soil Science Society of America 

Proceedings. 1974. %:672-675. 

Hatcher, R. J. Yellow birch regeneration on 

scarified seedbeds under small canopy 

openings. Forest Chronicle. 1966. 

- 42~350-358. 

Hoyle, M. C. Variation in foliage composition 

and diameter growth of yellow birch with 

season, soil and tree size. Soil Science 

Society of America Proceedings. 1965. 

- 29~475-480. 

Kujawski, Ronald F. and Paul C. Lemon. 

Ecological effectiveness of yellow birch in 

several Adirondack forest types. In: 

Vegetation-Environment Relations at Whiteface 

Mountain in the Adirondacks. J. G. Holway 

Marquis, David A. Controlling light in small 

clearcuttings. U.S. Forest Service Research 

Paper NE-39. 1965a. 16 pp. 

-- . Regeneration of birch 

and associated hardwoods after patch cutting. 

U,S. Forest Service Research Paper NE-32. 

1965b. 13 PP. 

. Germination and growth 

of paper birch and yellow birch in simulated 

strip cuttings. U.S. Forest Service Research 

Paper NE-54. 1966. 19 pp. 

. Silvical requirements for 

natural birch regeneration. In= Birch 

Symposium Proceedings. U.S. Forest Service, 

Northeast Forest Experiment Station. 1969. 

pp. 40-49. 

. Progress Report: Effect 

of light exposures on growth of ten Allegheny - - forest plants. U.S. ore st Service, 

Northeast Forest Experiment Station. 1972. 

4110-FS-NE-1108-44. 

/ # \ 

Roberge, M. R. Eclaircie dans une Erablaie a 

~gtre en vue de Produire du Bois D1oeuvre de 

Bouleau Jaune. Naturaliste canadien. 1975. 

- 902: 353-361. 

Sharik, Terry L. and Burton V. Barnes. Natural 

variation in morphology among diverse 

populations of yellow birch (Betula 

alleghaninensis) and sweet birch (8. lenta). 

Canadian Journal of Botany. 1979. 

57( 18) : 1932-1939. 

Tubbs, Carl H. and F. T. Metzger. Regeneration 

of northern hardwoods under shelterwood 

cuttings. Forest Chronicle. 1969. 5~333- 

337. 

Wearstler, Kenneth A., Jr. and Burton V. 

Barnes. Genetic diversity of yellow birch 

seedlings in Michigan. Canadian Journal of 

Botany. 1977. 55(22):2778-2788. 

and J. T. Scott (coinvestigators). Report 

No. 92. Atmosphere Science Research 

Center, State University of New York at 

Albany. 1969. pp. 162-191. 
Effects of Mexico's Selective Cutting System on 

Pine Regeneration and Growth in a Mixed Pine-Oak 

l 

( Pinus-Quercus 1 Forest . 

Laura C. Snook and Patricia Negreros c 

INTRODUCTION 

Over 80% of Mexico's industrial wood comes from 

pines (SARH 1978), most of which grow intermixed 

with oaks (Rzedowski 1978) in highland forests 

which cover 20 million has (SARH/SF 1984). Responsibility for silvicultural management of these and 

all of Mexico's forests rests entirely with the 

federal forest service (Ley Forestal 1960/1986). 

Since the 1950'~~ the country's forests have been 

exploited according to the silvicultural system 

known as the Metodo Mexicano de Ordenacion de 

Montes' (Mexican Method for Ordering Forests) 

(Carrillo 1955; Rodriguez 1958; Rodriguez et a1 

1959; Rodriguez & Rodriguez 1966). This selective 

cutting regime limits harvest intensity to 35% - 50% of the volume of desired (conifer) species, and 

at least until 1978 incorporated a diameter limit 

of 45 cm (Musalem 1979). In mixed forests, the 

application of this system often translates into 

selective extraction of less than 20% of total 

volume (FAPATUX 1980 ) . The Mexican method seeks to manage uneven aged 

stands by maintaining a balanced reverse Jshaped diameter distribution. It assumes that continuous regeneration and class-to-class recruitment 

will provide for sustained yields (Xlepac and Mass 

Porras 1968). As of 1981, although a few foresters 

had expressed doubts about the validity of these 

assumptions (Musalem 1979), no field studies to 

confirm or modify them had been published. It was 

1 Presented at the Symposium 'Current Topics in 

Forest Research : Emphasis on Contributions by 

Women Scientists', dosponscred by the USDA Forest 

Service Southeastern Station and the Department of 

Forestry, University of Florida; Gainesville, 

Florida, November 4-6, 1986. 

'~esearcher , National Institute for Research on 

Biotic Resources (INIREB), Xalapa, Veracruz, Mexico; 

and Researcher, National Institute for Research on 

Forestry, Agriculture and Animal Husbandry, (INIFAP) 

San Felipe Bacalar , Quintana Roo, Mexico. 

Abstract. Effects of the official selective harvesting system on a mixed pine-oak forest in Oaxaca 

were evaluated 20 years latex and compared to fmeyly cleared forest areas and unexploited forest. 

Pine regyeration in selectively cut for 5 st averaged 

only 5 m /ha basal area compared to 40 m /ha in formerly clearea areas. The correlation between pine 

regenexation and reconstructed residual basal area 

after hajvest was R = -0.82. Pine grohth increments 

of 4.6 rni/ha/year gccurred in selectively cut areas, 

compared to 11.4 m /ha/yr in formerly cleared areas. 

New regulations associated with the forest law of 

1986 may include replacement of the official selective cutting method by an even-aged silvicultural 

management system. However, the lack of markets 

for oak wood represents an obstacle to the implaentation of more intensive harvesting systems necessary 

to assure sustained yields of pine wood. 

Keywords: natural regeneration, silviculture 

decided to survey a pine-oak forest 20 years after 

exploitation to evaluate the effects of prior 

harvest by this method, particularly with regards 

to pine regeneration. 

THE STUDY SITE 

The study was carried out in the Zapotec community 

of San Pablo Macuiltianguis, in the Slerra de 

Juarez, Oaxaca. Their approximately 5000 ha of 

commercial forest is dominated by pines (Pinus 

patula, P, pseudostrobus, F-, ayacahuite, and E. 

rvdis) intermixed with species of oak including 

&uercus laurina, &. rugosa, p. crassifolia, Q. 

excelsa, Q, candicans, and 8, salicifolia. Madrone 

(Arbutus glandulosa), alder (Alnus acuminata), and 

other hardwood species occur as well (FAPATUX 1962; 

Perez and Perez 1984). 

Forest elevations range from 2200 m to 2700 m, 

averaging 2450 m. Slopes average 45%, and range 

from 15% to more than 100%. Annual precipitation 

is between 1500 and 2000 mm and is strongly 

influenced by humid wintex winds from the Gulf, 

knohn as 'nortes' , A marked dry season occurs 

during April and May. Average annual temperature 

has been estimated at 12" to 14* C (FAPATUX 19771, 

while a weather station at a slightly lower elevation just on the other side of the mountains 

registered an average temperature of 16.7* C and 

a precipitation of 1982 mm (Garcia 1981). 

These forests were concessioned to Mexico' s 

first newsprint paper factory, Fabricas de Papel 

Tuxtepec (FAPATUX), in the late 1950's, as a source 

of pine wood for cellulose (Diario Cficial Novaber 12, 1956). Selective cutting of pines began 

about 1959, but the second cutting cycle had not 

yet been initiated in 1981. 
METHODS 

Data Collection 

A 25 km timber extraction road known as 'brecha 

200' , which runs through the forest from west to 

east, was used as a transect. At 500 m intervals, 

courses were run perpendicular to the road between 

50m and 350 m into the forest, where sample plots 

were laid out. Distances from the road were 

selected using a random numbers table. 

Among 27 plots located by this method, 4 fell in 

unexploited forest and one in a former clearcut 

where a tower had been erected to support power 

lines. To give statistical context to this plot, 

an additional plot was located in the clearcut 

area, and complemented with two plots located in 

former agricultural fields abandoned 30 years before, 

one in 'Aqua Fria' and one behind the 'Comedor 

Cerro Machin' . The final data set for this study 

was based on 30 plots in 3 different forest types 

(selectively harvested, unexploited, and formerly 

cleared). 

Four radii ma ked at 3 intervals were used to 5 indicate 1000 m c'rcular pl ts with nested inter- 2 nal plots of 400 mi and 80 m . Trees 15 cm dbh and 

above were measured over the full 1000 m2 while 

trees betw en 5 cm and 14.9 cm dbh were measured 5 over 400 m . Trees 2 cm to 4.9 cm dbh were measured 2 only within the 80 m plot, Genus, dbh, crown class, 

and signs of injury were noted for each tree. Increment cores were taken of at least two small pines 

and at least two large pines on each plot. The former were used to determine the age and size range 

of post-harvest regeneration . Cores of large trees 

were taken to represent the range of diameter 

classes and provide data on increments. 

Data Analysis 

Measurements taken in 1982 showed the effects of 

past conditions on the density of pine regeneration. To relate these effects to causal factors 

required the reconstruction of the forest as it was 

just after harvest. While written records were 

unavailable, tree cores and information obtained by 

hearsay indicated that 1962 was the average year of 

regeneration subsequent to harvest and the clearcut 

for the power lines. 

All trees 20 years or younger in 1982 were thus 

considered post-harvest regeneration. In selectively 

cut and unexploited forest, nearly all of these 

trees measured less than 15 cm dbh, but differentiation of regeneration on each plot was verified 

according to increments, sampled ages, and diameter 

distributions. To permit comparison between the 

20 year old clearcut and the 30 year old abandoned 

fields, increments for the last ten years were subtracted from all tree diameters on the abandoned 

field sites. 

In the case of the clearcut and the abandoned 

fields, it was known that residual basal area had 

been zero at the time of regeneration establishment. 

To determine residual basal area at this time in 

selectively harvested forest, increments since 

1962 were subtracted from diameters of older trees. 

Average measured periodic increments of 0.44 cm/yr 

in pines less than 60 cm dbh and 0.36 cm/yr in 

pines greater than 60 cn dbh yielded respective 

diameter reduction factors of 8.8 cm and 7.2 cm 

over the 20 year post-harvest period. 

Oaks were not cored, both because of physical 

difficulties and because it was not known whether 

tropical oaks have annual rings. For lack of data 

on Mexican oak growth, diameters were reduced to 

1962 levels using the following increments, derived 

from an estimated volume increment of 2% a year 

(Mass P. 1977) and an oak volume table (FAFATUX 1977): 

Diam. class Annual increment 20 year reduction 

15 - 19.9 0.35 em 7.0 cm 

20 - 29.9 0.49 ern 9.8 cm 

30 - 39.9 0.69 cm 13.8 cm 

40 - 49.9 0.79 cm 15.8 cm 

50 - 59.9 0.89 cm 17.8 cm 

60 and over 1.30 cm 26.0 cm 

Using these reduction factors, average 1962 diameters and basal areas were determined for pines 

and oaks in each 1982 diameter class. Diameter 

distribution tables for each plot were then used 

to determine total residual basal area (Table I). 

Table I. Calculation of residual basal area in 

selectively cut forest ( Site 033 ) . Avg. class BA/tree # Total BA 

dbh 1982 1962 trees 1962 

Pines 

17.5 2 59 cm2 1 59 cm 2 

25.0 205 cm 2 2 

2 410 an2 

35.0 537 cm 6 3222 cm2 

2 45.0 1027 cm2 1 1026 cm2 

55.0 1673 cm 2 3346 cm I 

Oaks 

17.5 

25.0 

35.0 

45.0 

55.0 

2 Total residual basal area: 11,491 cm /lo00 m 2 

To compare unexploited forest conditions with 

selectively cut and formerly cleared forest, a 

similar process of diameter reduction and transformation to basal area in 1962 was applied, using 

the same estimates of oak increments as in the 

selectively cut forest, and the following periodic 

pine increments measured in the plots: 

Diam. class Annual increment 20 year reduction 

15 - 39.9 0.34 cm 6.80 cm 

40 - 49,9 0.38 cm 7.60 cm 

50 - 59.9 0.30 cm 6.00 an 

60 and over 0.24 cm 4.80 cm 
These same transformation ~ables were used to 

reconstruct che 1962 diamecer distribution of each 

site, By cornblning these with a pine volure table 

IFRPATVX 197?), i~ was possible to determine 1962- 

1982 volume increment by forese treatment, 

RESULTS ANC DISCUSSIOK 

As can be observed in Table 2, the average 

density of pine regcnera-cio~ twenty years after 

selective c cting was 5.2 rn /ha, only 13% of the '2 nearly 40 m ,/ha on chi3 formerly cleared sites. 

Regeneration establiskment in unexploitd forest 

during this period was negligible. 

The residual basal area in each case followed an 2 inverse pattsn to regenerati9nt averaging 34 m /ha 

in unexploited forest, 19.2 m in selectively cut 

forest, and 0 in the ciearcut and abandoned fields, 

A linear regression between residual basal area and 

basal area of regeneration yielded a correlation 

coefficient of R = -0.82, indicating that 67% of 

the variability in pine regeneration reflects the 

variation in residual basal area. This inverse 

relationship is no surprise since basal area is 

a measure of site occupation, The more growing 

space (light, water, nutrients ) occupied by residual trees, the less is available for regeneration 

establi shrne~t , 

Oak regeneration was insensitive,to variation in L residual basal area, yielding an R of only C.08. 

This no doubt reflects oaks9 greater shade tole - rance. It is notable that only in the unexploited 

forest, with the highest 'residual'basal area, is 

the average oak regeneration density approximately 

equal to and perhaps slA.ghtly greater than pine. 

Rates of suppression amongst pines followed the 

same pattern as reg~aeration density. In formerly 

cleared areas, 10% of the pines were suppressed by 

other pines. In selectively cut and unexploited 

forest, 80% and 100%, respectively, of the pine 

regeneration was suppressed, by a mixed canopy of 

pines and oaks. These trees will almost certainly 

die before reaching commercial size. 

Table 2. Pine and Oak Regeneration after 20 Years 

Ywmerly Selectively Unexploi ted 

Cl ear ed Cut 

Residu l BA 9 + C 0 l9,2 - L,7 34.1 - 3.0 1962 m /ha 

Oak re en. 9 + + 4- 6.2 - 2*1 3.6- 0.7 0.3 - 0,2 1982 rn /ha 

Growth 

Average periodic diameter increment between 1962 

and 1982 differed amongst pines i~ different forest 

treatments, Combining data for available diameter 

classes yielded averages of 1.3S cm/yr in the formerly cleared forest, 0.45 cm/yr in selectively cut 

forest, and 0.35 cm/yr in unexploited forest. In 

rhe first case, rapid growth rates reflect the 

youth and lor.ier range of diameters of the stands, 

and deereasing ring briachs over the last cwo or 3 

years indicace chat these rates are slowing as competition becomes more inte~se. 

Diaqeteu distribution tables for 1962 and 1982 

were transformed to volumes to determine the diff erence in volume incremer,t/ha yong forest treatmencs. These raged from 4.3 m /ha/year in the 

unexploited forest to 11.4 rn /ha/yr in the clearcut 

and abandoned fields (Table 3),comparing favorably 

with data for s plantation of P. patulgin I4acuiltianguis, which grew ac a rate of 12 m /ha/yr 

during the firsc 14 years aftex its establishment 

( FAF'ATUX 197 7 ) . 

Table 3. Volume increments/ha, pine only 

Formerly Selectively Unexploited 

Cl ear ed Cut 

Vol, pines 0 1962 

Vol, pines 228 m 3 

1982 

Increment 3 92 m 3 80 m 3 228 m 62-82 

Annual 11.4 m 3 4.6 m 3 4.0 m 3 

incr ,/ha 

Forest dynamics 

Selective cutting in the mixed forests of San 

Pablo bacuiltianguis, as in most of Mexico, was 

applied exclusively to pines. This has modified 

the relative dominance of pines and oaks (Table 4). 

While pines accounted for 64% of the total volume 

of the forest prior to exploitation (FAPATUX 19621, 

twenty years after the first selective cut they 

represented only 54% of the basal area. FJhile 

f orrnerly cleared sites were ocxnpl et ely dominated 

by pines, only 58% of the dominant trees in selectively cut sites were pines, while 40% of the 

dominant Crees were oaks. The intermediate pine/ 

oak relationship demonstraeed by data from the 

unexploited forest probably reflects the history 

of this particular area, which appeared to have 

regenerated after a fire about 40 years before. 

C-, pines -i- + 10% - 4 80% - 4 100% suppressed 
Table 4. Forest characteristics and proportions, 

1982 (adapted from Negreros & Snook 1984). 

Total BA 

BA Fines 

BA Cjaks 

% Pines 

% Oaks 

Pines 

% dom. 

Oaks 

% dom. 

Formerly 

Cleared 

Selectively Unexploi ted 

Cut 

'Data from FAPATCX (1962) . 20ther hardwood species made up the missing %. 

CONCLUSIONS 

The low-intensity selective cutting of pines in 

the pine-oak forests of the Sierra de Juarez has 

not stimulated adequate pine regeneration to provide for the replacement of harvested trees. On 

the contrary, these cuttings are encouraging the 

successional process of replacement of pines by 

oaks, as has been observed in the United States by 

various authors, among them Christensen and Peet 

(1983 and reviewed by Jardel (1985). 

Regeneration of pine was eight times greater in 

basal area (and twice as large in diameter) on 

sites subject to complete clearing. Growth rates 

followed the same pattern, annual volume increments 

of pine reaching levels 2.5 times greater in formerly cleared sites than in selectively cut forest. 

Thus it seems apparent that patch or strip clearcutting, a close imitation of agricultural abandonment and fires which apparently maintained pine 

dominance in these forests in the past, would be 

much more effective silvicultural methods than 

selective cutting for ensuring and maximizing future 

yields ofpine wood needed for cellulose and other 

industrial purposes. 

In fact, against the backdrop of the national 

guidelines for low-intensity selective cutting, a 

movement to intensify Mexican silviculture was 

initiated by a small group of concerned foresters 

in the mid-7OVs, and pilot projects using a system 

of even-aged silvicultural management were established on 2000 ha of mixed conifer forests by 

the end of the decade. The silvicultural system, 

called the 'Metodo de Desarrollo Silvicola' (Method 

of Silvieultural Development) is based on the 

application of seed tree regeneration cuts and 

periodic thinnings, and presumes to manage evenaged stands (&<usalm 1979). AS of 1983, 56,000 ha 

(less than 3% of Mexico's mixed conifer forests) 

were under rnanagemmt according to this method, and 

yielded 25% of the national production that year 

(SARH/SF 1984). 

A new Kexican forestry law was signed this year, 

replacing the forestry law of 1960 (Diario CKicial 

Nay 30, 1986) . While the associated forestry regulations will not he published until December, the 

appearance of the words "management plan" and 

"sustained yield" in the text of the new law ifor 

the first time) may foreshadow a modification of 

silvicultural guidelines. 

However, there are still obstacles to the 

implementation of a more intensive silvicultural 

system in Mexico's pine-oak forests. Among them 

is the lack of markets for oak wood. Mexico boasts 

over 120 recognized species of oaks (Rzedowski 

1978). Neither their taxonomy nor their wood 

technology is well known, and there has been little 

use of oaks for industrial purposes. 

Because loggers are paid by the cubic meter by 

the buyer of the wood, the lack of a demand for 

oaks makes it unlikely that these trees will be 

cut. In Nacuiltianguis, an average of 140 oaks 

occurred per hectares, representing nearly 20 m 2 

of basal area. This density is greater than the 

total residual basal area which so severely 

inhibited pine regeneration after the selective 

harvest. Unless these trees are cut, adequate 

pine regeneration cannot be expected. Thus oak 

markets should be developed as part of a new 

silvicultural strategy to assure the future of 

Mexico's pi~e resource. 

Portions of this paper, corresponding to the 

second author' s Masters thesis, were first published 

in Spanish (see Negreros & Snook 1984). The study 

could not have been carried out without the generous 

support of Dr. Margarita Soto, then Director of 

INIREB's Master's Program in Ecology and Biotic 

Resources. We also thank Ing. Jaime Escarpita for 

his openness in providing information about the 

forest and its history. Dr. Charles Peters' insights 

were invaluable , 

LITmTURE CITED 

Carrillo, G.N. 1955. Ordenacion de nuestros 

bosques. Editorial Cultura, Mexico D. F. 

Christensen, N.L. and R.K. Peet. 1981. Secondary 

forest succession on the North Carolina Piedmont, 

In: West, D.C., H.H. Shugart & D.B. Botkin (eds.) 

Forest Succession: Concepts and Application. 

Springer Verlag, New York. pp. 230-245. 
FAPATUX (Fabricas de Papel Tuxtepec). 1962. 

Proyecto definitive de la seccion de ordenacion 

No. 1, Unidad Industrial de Explotacion Forestal, 

Oaxaca, Mexico, 169 pp. 

FAPATUX (Fabricas de Papel Tuxtepec). 1977. 

Proyecto General de Ordenacion, Estudio Forestal 

~otogrametrico, Seccion de Ordenacion I, 111, IV. 

Oaxaca, Mexico, 170 pp. 

FAPATUX (Fabricas de Papel Tuxtepee). 1980. 

Sintesis del estudio sbore la constitucion en 

1958 de 10s bosques mezclados de coniferas y latifoliadas de la Sierra de Juarez, Oaxaca, comparado con lo mismo en 1978. 

Garcia, E. 1981. Modificaciones a1 sistema de 

clasif icacion climatica de Koeppen. Instituto 

de Geografia, Universidad Nacional Autonoma de 

Mexico, pp. 155 - 157. 

Jardel, E. 1985. Una revision critica del Metodo 

Mexicano de Ordenacion de Bosques desde el punto 

de vista de la ecologia de poblaciones. Ciencia 

Forestal 58:3-16. 

Klepac, D. & J. Mass Porras. 1968. El tiempo de 

paso y su importancia en la ordenacion de 

montes. Mexico y sus Bosques (enero-febrero): 

24-32. 

Mass Porras, J. 1977. Los encinos como fuente 

potential de madera para celulosa y papel en 

Mexico. Ciencia Forestal 2( 5) :45-46. 

Musalem L, F.J. 1979. Las bases y primeras 

acciones del Programa Nacional de Mejoramiento 

Silvicola en Bosques de Coniferas. Productos 

Forestales de Michoacan (PROFORMICH), Morelia, 

Michoacan, 40 pp. 

Negreros, P. & L. Snook. 1984. Analisis del efecto 

de la intensidad de corta sobre la regeneracion 

de pinos en un bosque mezclada de pino-encino. 

Ciencia Forestal 47 : 48-61. 

Perez, P.E. & C.G. Perez. 1984. Estudio ecologico 

floristico y el signif icado econornico de la 

vegetation en la comunidad de Macuiltianguis, 

Oaxaca . Tesi s Prof esional , Universidad Autonoma 

de Chapingo, Dpto. de Bosques. 

Rodriguez C,, R, (1958) Discusion de formulas para 

el calculo de la productividad rnaderable y 

exposicion del Metodo Mexicano de Ordenacion de 

Montes de especies coniferas. Cornision Forestal 

del Estado de Michoacan. 

Rodriguez G., R., R. Mendoza & R. Barrena. 1959. 

El Hetodo Mexicano de Ordenacion de Montes. 

Apendice 7. Proyecto de Ordenacion ~orestal de 

la Unidad INdustrial de Explotacion Forestal 

"Michoacana de Occidente" . 

Rodriguez C., R. & M, Rodriguez. 1966. Generacion 

del Metodo Mexicano de Ordenacion de Bosques. 

Mexico y sus Bosques ( septiembre - dicidre) : 2-4. 

Rzedowski, J. 1978. Vegetaci.cn de Mexico. Editorial Limusa, Mexico D.F. 432 pp. 

SARH (Secretaria de Agricultura y Recursos Hidraulicos). 1978. Estadisticas del Recurso Forestal 

de la Republics Mexicans. Direction General del 

Inventario Forestal. Publicacion #45. Mexico. 

S;IRH/SF (Secretaria de Agricultura y Recursos 

Hidraulicos/ 'ubsecretaria Forestal). 1984. 

Mexico Forestal. Cifras 1983. 59 pp, 
Gains from Superior Tree Selection in Black 

Spruce and White sprucel 

Katherine K. carter2 

Among the conifer species native to the forests 

of Maine, the spruces (Picea spp.) are of greatest interest to forest industry because of their 

superior pulping qualities and their widespread 

distribution throughout the state. Tree improvement programs for white spruce (P. glauca 

(Moench) Voss) and for black spruce (P. mariana 

(Mill.) BSP) have been initiated in the past 

decade. Research to evaluate selection methodology and to estimate potential gains has been 

carried out at the University of Maine in cooperation with local industry and with the U.S. 

Forest Service. 

Results from progeny tests of superior trees 

selected in natural stands of white spruce and 

black spruce are reported here. These early 

results indicate that different selection methods 

may be preferred for each species. 

WHITE SPRUCE 

White spruce was one of the first species to be 

included in tree improvement research programs. 

During the 1960ts, superior trees were located 

by field foresters in Maine and New Hampshire, 

and graded by Clyde Hunt of the U.S. Forest 

Service. A comparison-t'ree selection method 

was used, with 2 or 3 comparison trees in most 

stands. The parent trees ranged in age from 

18 to 75 years; most were 30 to 50 years old. 

They averaged 9 percent greater in DBH and 8 percent greater in height than comparison trees in 

the same stands. A north-south range of almost 

3 degrees in latitude was related to different 

rates of height growth: Northern parents had a 

mean annual increment in height of 1.3 ftiyear, 

while southern parents averaged 1.9 ftlyear, 

Open-pollinated seed from 23 parents was 

collected to establish a half-sib progeny test. 

Seed was sown in the New Hampshire state nursery 

in 1971. In 1974, 3-0 seedlings were lifted and 

planted at a test site located on abandoned farm 

]presented at the symposium, "Current Topics in 

Forest Research: Emphasis on Contributions by 

Women Scientists," Gainesville, FL, 4-6 Nov. 1986. 

Maine Ag. Expt. Station publication no. 1149. 

2~ssociate Professor Forest Biology, University of Maine, Orono, ME 04469. 

Abstract.--Open-pollinated progeny tests were 

established to assess the gains attributable to 

plus-tree selection in black spruce and white 

spruce in Maine. Of 23 selected families of white 

spruce, all but one were taller than nursery-run 

checks after 17 growing seasons in the field. 

Height gains averaged 23 percent. Latitude of 

the parent tree was negatively correlated with 

progeny growth rates. For black spruce, progeny 

of plus-trees selected using the baseline method 

were no taller than offspring of average trees, 

at age 7. Heritability values for black spruce 

are low, indicating that family selection might 

be more effective than individual tree selection, 

land near Moscow, Maine. Nursery-run white 

spruce seedlings from the New Hampshire and Maine 

state nurseries were included as check seedlots, 

as were seedlots of red sPruce iP. rubens Sara.) 

and Norway spruce (P. abies (i. j-~arst). -!'he4 ' 

experimental design is a randomized complete 

block with 6 replications and 10 trees ber plot. 

After 11 growing seasons (14 years from seed), 

survival averaged 71 percent. The average height 

for all select offspring was 9.9 ft, which represents a gain of 19 percent over the New Hampshire check and 36% over the Maine check. When 

northern and southern families are compared with 

the appropriate check lot, average height gains 

are 25 percent to 28 percent (Table 1 ). White 

spruce were also taller than the Norway spruce 

(8.7 ft) and red spruce (7.2 ft) seedlots. 

Height measurements were subjected to analysis 

of variance to determine heritability. A heri tability value of h2 = 0-4 was calculated, which 

is close to the value of 0.35 reported by Mohn 

et al. (1976) in Minnesota. Height at age 74 was 

highly correlated with height at ages 11 and 6, 

and with growth of the terminal leader at age 6, 

Mean annual increment of the parents was correlated with progeny height at age 6 but not at 

later ages (Table 2). 

BLACK SPRUCE 

During the 1970ts, interest shifted toward 

black spruce as a plantation species because of 

its rapid juvenile growth and its relative resistance to the spruce budworm. Previous work by 

Morgenstern (1 974) had indicated 7 i ttle re1 ationship between parental growth rates and juvenile 

growth of their progeny. In order to explore 

this relationship further and to test the baseline method of selection, 16 stands of black 

spruce throughout Maine were identified for 

intensive study. Five to 10 dominant or codominant trees in each stand were selected at 

random and measured to provide baseline data 

for mean annual height and diameter increments. 

'"Plus" trees were then located which were 1.0 

to 2.5 standard deviations above the average 

for that stand (Kenlan 1981). Cones were collected from plus trees and from two or more 

average trees (those closest to the baseline 

values) in each stand. 
Table 1.--Comparative heights for white spruce 

progenies of northern and southern select parents. 

Superiority of northern progeny is compared to 

Maine check seedlot; southern progeny is compared 

to New Hampshire check seedlot 

Seed Height 01 0 

source (ft) superiority 

Northern Trees 

AC 47 

AC 21 

AC 50 

AC 31 

AC 39 

AC 54 

AC 40 

AC 78 

AC 37 

ME check 

Southern Trees 

AC 71 

AC 55 

AC 06 

AC 83 

AC 85 

AC 16 

AC 73 

AC 02 

AC 66 

AC 67 

AC 68 

AC 72 

AC 60 

NH check 

AC 56 

5 3 

3 7 

3 3 

32 

2 3 

23 

2 2 

2 1 

14 

- - 

Ave. 28 

4 5 

39 

3 7 

3 4 

3 3 

2 9 

2 7 

2 7 

23 

19 

16 

16 

2 

- - 

- 1 

Ave. 25 

Table 2.--Correlations among parent and progeny 

height and growth parameters, for Spruce-Fir 

Committee white spruce progeny test in Moscow, 

Maine 

Height Growth Height Height 

1976 1976 1981 1984 

Parental .64* .58* .37 .34 

height (MAI) 

Height 1984 .75* .75* .95* - - 

Height 1981 .82* .73* - - - - 

Growth 1976 .87* - - - - - - 

* significant at 0.05 level. 

Seedlings were grown in the nursery for 2 years 

and then outplanted at 3 field sites in a randomized design with 5 rep1 ications of 3-tree plots. 

Seedling height was measured at ages 1 and 2 

(nursery), and ages 5 and 7 in the field. 

At age 7, overall survival in each plantation 

ranges from 88 percent to 94 percent. Overall 

mean height varies from 3.8 ft to 4.5 ft among 

the plantations; within each plantation family 

mean heights range from approximately 80 percent 

to 120 percent of the plantation mean. 

Measurements of seedling height in the nursery 

revealed a negative correlation with latitude of 

the parent stand, and significant differences 

(0.05 level) among stands. After 5 years in the 

field, the stand effect is still significant at 

2 out of 3 plantations but the correlation with 

latitude has disappeared. 

Examination of fifth-year data indicates that 

parental selection has been ineffective for improvement of juvenile growth rate. There is no 

significant difference in overall height between 

offspring of "select" and "average" parents 

(Table 3); nor is there a significant correlation 

between parental height or DBH and progeny height. 

There are, however, significant differences in 

family height when data for all 3 plantations is 

combined (Table 4). Based on the combined data 

for a1 1 3 p1 anti ng sites, individual -tree heri tability is 0.19. When the 3 plantations are 

examined separately, however, the family effect 

is non-significant at 2 of the sites and heritability ranges from 0.08 to 0.27. Correlations 

of Family height ranking across the 3 plantations are non-significant in 2 cases, and low 

(r = 0.48) in the third case. 

Table 3.--Mean height of select and average black 

spruce progeny 

Age and Location Progeny Height (in) 

Select Average 

1 - Nursery 

2 - Nursery 

5 - Wowland 

5 - Demo Pond 

5 - Loon Lake 

7 - Howland 

7 - Demo Pond 

7 - Loon Lake 

Table 4,--Analysis of variance for height of 

black spruce families after 5 years in the 

field (age 7 from seed) 

Source of Degrees of Mean Square F 

Variation Freedom 

Site 2 59.7962 50.31** 

Fami ly 6 7 3.0001 2.52** 

Rep1 ication 11 6.8152 6.86** 

(site) 

Site x family 127 1.1884 1.19 

Error 1722 0.9996 

** significant at 0.01 level. 
DISCUSS I ON LITERATURE CITED 

Results of these plus-tree selection and openpollinated progeny tests indicate that different 

selection strategies may be desirable for white 

spruce and black spruce. Comparison-tree selection of superior white spruce in natural stands 

has resulted in substantial height gains when 

the progeny are compared with nursery-run check 

seedlings of unknown parentage. High calculated 

heritabi 1 ity values for height also indicates 

that comparison-tree selection would be expected 

to produce gains in white spruce. 

Plus-tree selection was not effective in identifying black spruce parent trees that produce 

fast-growi ng progeny. The uninspiring performance of "plus-tree" progeny and the low heritabi 1 i ty values indicate that farni ly selection 

in progeny tests, rather than individual tree 

selection of parents, will be required to identify superior trees for inclusion in breeding 

programs. It also appears that black spruce 

field tests should include larger numbers of 

seedlings to provide a more reliable assessment 

of family performance, due to the relatively low 

heritabi 1 ity value for juvenile height in this 

species. 

Kenlan, K.W. 1981. Genetic variation in progeny 

from sixteen stands of black spruce in Maine. 

M.S. thesis, University of Maine. 91 p. 

Mohn, C.A., D.E. Riemenschneider, W. Crowell, and 

L.C. Peterson. 1976. A white spruce progeny 

test-seedling seed orchard: 72th year progress 

report. Lake States For. Tree Impr. Conf. 

Proc. 12:98-107. 

Morgenstern, E.K. 1974. Selection of black 

spruce progenies for the genetic improvement 

of height growth. For. Chron. 50(4) : 160-1 62. 
Geographic Variation of Allozymes in Eastern 

Larch (Larix laricina (Du Roi) K. ~och) From 

Northwestern Ontario 1 

Peggy H. Knowles and Dan J. Perry 2 

Isozyme analyses of natural populations of numerous plant species have indicated that forest 

trees are among the most genetically variable 

(Hamrick 1979). The majority of this diversity 

has been found to be distributed within populations as compared to that among populations 

(O'Malley and others 1979; Yeh and O'Malley 1980; 

Brown and Moran 1981; Yeh 1981; Guries and Ledig 

1982; Wheeler and Guries 1982; Dancik and Yeh 

1983; Hiebert and Hamrick 1983; Furnier and 

Adams 1986). Conifer species of the boreal forest generally have broad geographical distributions and have not been as thoroughly studied due 

to the problematic nature of rangewide access. 

Larch is distributed from Newfoundland west to 

the Mackenzie River drainage and from the northern limit of tree growth south to the central 

Canadian prairie provinces in the west and the 

northern states in the east. A disjunct portion 

of the range also occurs in central Alaska and 

the Yukon. Ecologically, larch is notable for 

its successful growth under extremely varied 

climatic and soil conditions (Fowells 1965). 

The objective of this study was to assess the 

allozyme variation in eastern larch (Larix 

laricina (Du Roi) K. Koch) systematically across 

a substantial portion of its range in northwestern Ontario . 

MATERIALS AND METHODS 

Ten trees from each of two stands in close 

proximity at each of ten sites were sampled across northwestern Ontario (Figure 1). The twenty trees at each of ten sites were treated as a 

'presented at the symposium on Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists. Gainesville, Florida, November 

4-6, 1986. 

'~ssistant Professor of Forestry/Biology and Research Associate, respectively, Lakehead University, Thunder Bay, Ontario, Canada 

Abstract.-- Allozyme variation in eastern larch 

across northwestern Ontario was assessed by transplanting 20 seedlings from each of 10 pooulations to greenhouse conditions, rooting vepetative tissue, and subjecting root tips to electrophoretic analyses. Five loci encoded by five 

polymorphic enzyme systems were assayed. Allelic 

heterogeneity tests indicated no significant differences among pooulations. F statistics indicated little pooulation differentiation with a 

single po~ulation indicating a heterozygote deficiency. Multi-variate analyses su~oorted the 

univariate results; no statis'tically significant 

multilocus discrimination obtained among the 

10 populations. However, a small amount of 

patchy differentiation is evidenced and may be 

due, in part, to inbreeding. The lack of differentiation may result from the relatively homogeneous boreal environment and the relatively 

short occupation since glaciation. 

single population. Sampled trees were 10 to 200 

cm. in height and generally 10 meters apart with 

a separation of 5 meters in a minority of cases. 

Trees were removed from the field with balled 

roots, transferred to greenhouse conditions, and 

potted. A three month stabilization period was 

allowed at which time a branch end was removed 

from each sampled tree and vegetatively propogated. After four months growth of the rooted cuttings, one to three actively growing root tips 

from this clonal material were excised and ground 

in 2 drops of the following grinding buffer: To 

0.2 g ascorbic acid, 0.095 g cysteine, I ml tween, 

2 ml. 10% MgC12, 2 ml 10% CaC12, 17.1 g sucrose, 

20 mg glutamic acid, 2 drops b-mercaptoethanol, 

add 0.1M tris/HCl (pH 7.5) to 100 ml volume. The 

grindate was then subjected to electrophoretic 

analysis (Table 1). Five loci encoded by five 

polymorphic enzyme systems (Table 1) were assayed 

for all individuals except for five trees that 

had insufficient 6pg activity. Details of the 

x 

Manitoba 1- 

<h. 

Quebec 

Figure 1, Map of site locations for larch samples 
TABLE I. Enzyme systems sssayed in larch rsot tlssue 

Buffer, 

Lociis E.C. Piumber Systeml~uffer systems: 

Trls-c~trate ph 8.5 gel buffer; lithldn bcrate pH 8.i e?ectrode buffer (fiidc;eray --- :'., 1970). Pun at 300 

roits. 6 .-hisiidjne-tr;s p,Y 7.0 gel bu4fe-; Tris-citrate pH 7.0 electrode buffer (Florence, 1%:). Rsn at 200 volts. 

inheritance of these allozymes are described by 

Cheliak and Pitel (1984). 

Allelic and genotypic frequencies were tallied 

for each population and tested for allelic heterogeneity and deviation from Hardy-Weinberg equilibrium respectively. In both instances, the maximum likelihood G procedure was used (Sokal and 

RohLf 198l), Since this procedure is not robust 

for small sample sizes within any row by column 

cell, alleles with low frequencies (less than 2) 

were bulked with the allele for the next lowest 

frequency. 

A hierarchical analysis of population structure 

was conducted by means of F statistics (Wright 

1969; Kirby 1975; Nei 1977). The statistics were 

calculated according to Neik (1977) Gethod. The 

average deviation of a subpopulation's genotypic 

proportions from Hardy-Weinberg equilibrium is 

measured by F with a negative value indicating 

an excess of izterozygotes. Similarly, FIT 

measures the same deviation but relative to the 

total population rather than the subpopulation. 

%naily, FST measures the extent of differentiation among subpopulations, 

The pattern of multilocus variation among the 

10 populations was examined by subjecting the data 

to principal components analysis and dicriminant 

functions analysis, These procedures have proven 

useful to the understanding of genetic factors 

underlying geographic differentiation (Yeh and 

others 1985). Genotypic data were coded according 

to the method of Smouse and others (1982). Each 

genetic variable is expanded to (n - I) independent variables where n is the number of alleles 

at a particular locus. This scheme incorporates 

both gene frequency and genotypic frequency information and resulted in the construction of 10 

genetic variables which were then summarized by 

principal components analysis into factor loadings 

for each individual. The principal components 

procedure constructs several "factors" fitbat summarize the genetic variation and the loading for 

each individual is that individual's contribution 

to the newly constructed muitidimensional "factor". 

Five of these sumary variables or "factors" were 

subjected to discriminant analysis which statistically maximizes the variation among groups in 

order to distinguish among the 10 populations. 

RESULTS 

Frequencies for the most common allele at the 

five polymor~hic loci for each of the fO populations are listed in Table 2. Note that the common allele is actually fixed for Pgm and Dia in 

four and five of the 10 populations respectively. 

Tests for deviation from Hardy-Weinberg expectations indicated no siqnificant departures. Sirnilarly, no significant allelic heteropeneity was 

detected among the 10 populations. 

TABLE 2. Frequency of most common allele. 

Site -. 

., 7, a !.!&- 1 Pg{ -2 23" 6-pg 

A sumary of the F statistics is provided in 

Table 3. Values for FIS are presented separately 

for each population at each locus. The average 

FIT values over all populations for each locus 

and the single FST values for each locus are 

presented. In those populations where alleles 

are fixed, the FIS statistics have not been calculated, Note the lack of pattern for the direction of deviation among the FIS values, except 

for the locus 6-pg that shows a consistent but 

small excess of heterozygotes over all populations, Population 1 shows the greatest value 

for mean F1s (0.203). 

TABLE 3. Values of F for each of the ten larch populatqons and mean vai%es of FIT and FSI for all ten populations. 

Statistic Populatron , 2 f . : ,' . s-pg Mean 

':.v. = :nsufficient varlatior for FIS calculations. 

The results of the orincipal components analysis indicated that each of the ten extracted factors, corresponding to the ten input genetic variables, contributed a~proximately equally in accounting for the existing variation. An examination of the Loadings (not shown) indicated that 

each princiaal component reflected variation in 

very few loci, suggesting that groups of penes 

were not covarying in the same pattern. Individual factor loadings for the first five factors, 

accounting for 62% of the variation, were chosen 

to submit to the discriminant analysis. The 

first function generated by the analysis accounted for 40% of the variation but was not statistically significant indicating that there was no 

significant discrimination among the populations. 

A graphical illustration of the first and second 
functions is presented in Figure 2, In combination, these two functions account for 66% of the 

variation existing in the factor scores. Figure 

2 indicates that dFfferentLation among populations is minimal with populations I and 5 showing 

divergence from all other ~opulations as a group, 

Function 1 10 I 

Figure 2.--Graphical plot of the centroids representing the ten eastern larch populations 

based on the first two functions of the disriminant analysis. 

The results indicate that the isozyme structure 

of larch does not exhibit marked heterogeneity 

across the geographic area studied, Even though 

the sampling range extended over a 1300 km. distance in a north-south direction with a 2600 km, 

east-west distance, no consistent trends in isozyme variation were detected, The statistical 

evidence from allelic heterogeneity tests, FST 

statistics, and the discriminant functions procedure consistently support this general conclusion. However, the multivariate analysis does 

provide evidence for small but distinctive differ-- 

entiation of two populations from all others as 

a group. Even though this differentiation does 

not attain statistical significance, it may represent a biologically meaningful "'patchiness" 

of genetic structure within this portion of its 

range. 

Deviations from Hardy-Weinberg equilibrium proportions as measured by FIS warrant closer examination. Population I shows an excess of homozygotes, This result corresponds to a previous 

finding of a relatively low level of outcrossing 

for different trees at the same Location (Rnowles 

and others, 1986). This outcrossing study focused on seeds from samples of mature trees at 

locations corresponding to numbers I, 5, 6, 7, 

and 9 of the present study. The multilocus outcrossiilg estimates, tm (%aw and Allacd, 19821, 

represent the frequencies of outcrossed progeny 

and were calculated as ,537, .735, .699, -908, 

and -768 for these five sites respectively, The 

ecological and/or genetic factors that are 

encouraging this relatively high level of inbreeding at site 1 are reflected by the seedliny population sampled from the same location in the 

present study, 

The unzsuai genetic structure of popxlation 1 

is further emphasized by the results of the multivariate analyses, Even though the differences 

among the ten pa~ulations subjected to the discriminanc analysis are not statistically significant, population I shows a substantial deviation from most other po~ulations (see Fipure 2). 

We interpret that this deviation results from the 

unusual gerzutypic structure of po~ulation P aerhaps due to inbreeding at this site. 

The actual Level of differentiation among ~opulations, as measured by the v,, statistic, is 51 similar to that found in several other forest tree 

species (Table 4). The GST statistic used for 

this cornsarison was desigaed by Nei (1975) and is 

mathematically identical to FS~ (Sei, 1977). 

Gullberg and others (1985) similarly compared 

population differentiation from several studies 

of conifer ~opulations in the Literature concluding that in areas that had been covered by ice 

during glaciation events, conifers had generally 

lower differentiation than those occu~ying unglaciated areas, The present findings suDDort 

this conclusion with a previously undocumented 

spec kes , Lar i x iar ic ina , 

TABLE 4. Poppulat~o~ differentiation jGST. Nei, 1935) of some conifer soecles. 

Spec~es 'ST Reference 

;y Zveszris -. 0.02 Gullberg et ci.!i985) : 2~;~s res <?osc . . 0.00 Fowler and Morris (1977) r ,?ti3 pCLp:da 0.02 Guries and iediq (1982) 

iiqus bi-nksia-u 0.02 Dancik and Y@k (1983) 

pir' *a- ~cntcrtii 0.06 Wheeler and Guries (19821 

;ends rnsntics So 0.15 Steinhoff et cJ. (19833 

Pinus pc~dergsa -, '

0.1% O'Malley et ai. (19791 izni~s mn'iatn 0.13 Brown and Moran !198lj PLV~S jeff17e3i 0.14 Furnier and Adarns (2986) 

.z~<ceu s~yrhe~st~ 0.08 Yeh and El-Kassaby (1980) 

i7se2idots~gu rnen~ics-li 0.03 Yeh and O'Maliey (1980) 

What accounts for the generally homogeneous 

~enetic structure of larch across northwestern 

Ontario? One explanation is the lack of time for 

differentiation since larch has occu~ied the area 

for only about 208 to 300 generations since the 

last glaciation. Davis (1983) indicates that 

larch moved northwards and eastwards from the 

Great Plains reaching the present-day ~anada/ 

United States border approximately lO,OQO years 

ago after spruces had been well established, 

Further, the relatively undifferentiated vegetati-~e and topographic characteristics of the 

boreal region restricts selective forces to those 

of climatic origin. Conifers from the western 

part of the continent with mountainous and/or 

discontinuous distributions can be subject to 

stronger differential se2eccion and also tend to 

show higher genetic differentiation (O %alley, 

ALlendorf and Blake 1939; Brown and %oran 1981; 

Steinhoff, Joyce and Fins 1983; Furnier and Adarns 

1986). Finally, as a ~ind-pollicated snecies in 

a boreal region, larch ~onulations suffer no 

significant obstruction to gene flow, Yowever, 
the previously mentioned recent finding of relatively high levels of self-fertilization in larch 

(Knowles and others, 1986) indicates that this 

factor may be less important in contributing to 

among-populat ion homogeneity. 

In conclusion, the larch populations sampled 

from northwestern Ontario show no statistically 

significant differentiation based on isozyme 

variation. This is possibly due to the relatively homogeneous boreal environment and the relatively short occupation of this environment 

since glaciation. A small amount of patchy differentiation is evidenced and 

part, to inbreeding. A more complete range-wide 

investigation incorporating more loci and larger 

sample sizes would be a valuable contribution to 

the understanding of this boreal conifer. 

Financial support was provided by the Natural 

Sciences and Engineering Research Council of 

Canada Grant F0004 and the Canadian Forestry 

Service. For field work, we are grateful to 

Olenka Bakowsky, Tim Dickinson, Rob Farmer, 

Heather Foster, Maddie Maley, Gwen O'Reilly, Rob 

Reinholt, and Ian Searle. Lea Tarnowsky provided 

valuable assistance with the laboratory analyses. 

LITERATURE CITED 

Brown, A.H.D.; Moran, G.F. Isozymes and the 

genetic resources of forest trees, In: Conkle, 

M.T. tech. coord. Proceedings, symposium on 

isozymes in North American forest trees and 

forest insects; 1979 July 27; Berkeley, CA. 

Gen. Tech. Rep. PSW-48. Berkeley, CA: U.S. 

Department of Agriculture, Forest Service, 

Pacific Southwest Forest and Range Experiment 

Station; 1981. 

Cheliak, W.M.; Pitel, J.A. Techniques for starch 

gel electrophoresis of enzymes from forest 

tree species. Information Report PI-X-42. 

Petawawa National Forestry Institute. Canadian 

Forestry Service, Agriculture Canada. 1984. 

Dancik, B.P.; Yeh, F.C. Allozyme variability 

and evolution of lod~e~ole - pine (Pinus contor- A pp 

- ta var. latifolia) and jack pine (P, banksiana) 

in Alberta. Canadian Journal of Genetics and 

Cytology 25: 57-64; 1983. 

Davis, M.B. Holocene vegetational history of 

the eastern United States. In: Wright, H.E. 

Jr., ed. Late quaternary environments of the 

United States. Volume 2, The Holocene. 

Minneapolis: University of Minnesota Press; 

1983. pp. 166-181. 

Florence, L.Z. Allozymic variation and population structure in loblolly pine. S.F. Austin 

State University of Texas; 1981. Thesis. 

Fowells, H.A. comp. Silvics of forest trees of 

the United States. Agric. Handb. 271. Washinton, DC: C.S. Department of Agriculture, 1965. 

762 pp. 

Fowler, D.P.; Morris, R.W. Genetic diversity in 

red pine : evidence for low genic heterozygosity . Canadian Journal of Forest Research 7: 343- 

347; 1977. 

Furnier, G.P.; Adams, W,T. Geographic patterns 

of allozyme variation in Jeffrey pine. American Journal of Botany 73: 1009-1015, 1986. 

Gullberg, U.; Yazdani, R.; Rudin, D. (and others). 

Allozyme variation in Scots pine (Pinus 

sylvestris L.) in Sweden. Silvae Genetica 

34: 193-201; 1985. 

Guries, R.P.; Ledig, F.T. Genetic diversity and 

population structure in pitch pine (Pinus 

rigida Mill.). Evolution 36: 387-402; 1982. 

 amr rick, J.L. Genetic variation and longevity. 

In: Solbrig, O.T.; Jain, S.; Johnson, G.B.; 

Raven, P.H., eds. Topics in plant population 

biology. New York: Columbia University Press; 

1979 pp. 84-113. 

Hiebert, R.D.; Hamrick, J.L. Patterns and levels 

of genetic variation in Great Basin bristlecone pine, Pinus longaeva. Evolution 37: 

302-310; 1983. 

Kirby, G.C. Heterozygote frequencies in small 

populations. Theoretical Population Biology 

8: 31-48; 1975. 

Knowles, P; Furnier, G.R.; Aleksi.uk, M.A.; 

Perry, D.J. Significant levels of self-fertilization in natural populations of tamarack. 

Submitted to Canadian Journal of Botany. 

Nei, M. Molecular population genetics and evolution. Amsterdam: North Holland Press; 1975. 

Nei, M. F-statistics and analysis of gene diversity in subdivided populations. Annals 

of Human Genetics 41: 225-233; 1977. 

~'Malley, D.M.; Allendorf, F.W.; Blake, G.M. 

Inheritence of isozyme variation and heterozygosity in Pinus ponderosa. Biochemical 

Genetics 17: 233-250; 1979. 

Ridgeway, G.J., Sherburne, S.W.; Lewis, R.D. 

Polymorphisms in the esterases of Atlantic 

herring. Transactions of the American Fisheries Society 99: 147-151; 1970. 

Shaw, D.V.; Allard, R.W. Estimation of outcrossing rates in Douglas-fir using isozyme 

markers. Theoretical and Applied Genetics 

62: 113-120; 1982. 
Smouse, P.E.; Spielman, R.S.; Park, M.H. Multiple-locus allocation of individuals to groups 

as a function of the genetic variation within 

and differences among human populations. American Saturalist 119: 445-463; 1982. 

Sokal, R.R.; Rohlf, F.J. Biometry, 2d ed, San 

Francisco: W.H. Freeman and Go.; 1981. 859 pp. 

Steinhoff, R.I.; Joyce, D.G.; Fins, L. Isozyme 

variation in Pinus monticola. Canadian Journal 

of Forest Research 13: 1122-1132; 1983. 

Wheeler, N.C.; Guries, R.P. Population structure, genic diversity, and morphological variation in Pinus contorta Dougl. Canadian Journal 

of Forest Research 12: 595-606; 1982. 

Wright, S. Evolution and the genetics of populations. Vol. 2. The theory of gene frequencies. Chicago: University of Chicago Press; 

1969. 511 pp. 

Yeh, F.C. Analyses of gene diversity in some 

species of conifers. In: Conkle, M.T. tech 

coord. Proceedings, symposium on isozymes 

of North American forest trees and forest 

insects; 1979 July 27; Berkeley, CA. Gen. Tech. 

Rep. PSW-48. Berkeley, CA: U.S. Department of 

Agriculture, Forest Service, Pacific Southwest 

Forest and Range Experiment Station; 1981 : 

pp. 48-52. 

Yeh, F.C.; El-Kassaby, Y.A. Enzyme variation in 

natural populations of Sitka spruce (Picea 

sitchensis). Genetic variation patterns 

among trees from 10 LCFRO provenances. Ganadian Journal of Forest Research 10: 415-422; 

1980. 

Yeh, F.C.; O'Malley, D.M. Enzyme variation in 

natural populations of Douglas-fir, Pseudotsuga 

mensziesii (Mirb.) Franco, from British Columbia. 1. Genetic variation patterns in coastal 

populations. Silvae Genetica 29: 83-92; 1980. 

Yeh, F.C.; Gheliak, W.X., Dancik, B.P. (and 

others). Population differentiation in lodgepole pine, Pinus contorta spp. latifolia: 

a discriminant analysis of allozyme variation. 

Canadian Journal of Genetics and Cytology 

27: 210-218; 1985. 
Soil and Foliage Analysts in Intensive Forest 

~ana~ementl 

Sharon 6. Haines and L, Kayne bines2 

Only recently have Crees been considered a 

crop. ..,foresters must know as much about how 

to manage crop trees as a farmer does about 

managing his agricultural crop, 

(Waines, 1978b) 

Scientists have spent over a century 

attempting to quantify the nutritional status of 

plants and the nutrient-supplying capacity of 

soils. Compilations by Goodall and Gregory 

(1947) and Chapman (1966) summarize approaches 

used and diagnostic criteria developed for 

plants and soils. When compared to most 

agronomic and horticultural crops, relatively 

little is known about nutrient requirements of 

forest trees. Bauer (1910) and Kubler (1912) 

provided most of the available nutrient data for 

forest trees until the 1930s. 

The scarcity of data on mineral nutrition of 

forest trees was emphasized during a Duke 

University symposium in 1958 (Anonymous, 1959). 

Subsequently, progress on the issue of tree 

nutrition and modification of nutrient status 

via forest fertilization was summarized at a 

1967 symposium at the University of Florida 

(Anonpous, 1968). More recent advances 

including use of operational fertilization in 

intensive forestry have also been summarized 

(Bengtson, 1979; Pritchett and Gooding, 1975). 

The use of soil and foliage analysis in 

agronomy and horticulture is a rather highly 

l~resented at spposium on Current Topics in 

Forest Research--Emphasis on Contributions by 

Women Scientists, Go-sponsored by USDA Forest 

Service, Southeastern Station and the Department 

of Forestry, University of Florida, Gainesville, 

FL 32611, Noveaber 4-6, 1986, 

2~ection Leader, Soils Research, and 

Manager, Forest Productivity and Research, 

respectively, International Paper Company, 

Southlands Experiment Forest, Bainbridge, GA 

3l717, 

Abstract,--Forest management decisions often 

require knowledge of soil and foliage nutrient 

levels, Accurate interpretation of analytical 

results requires knowledge of sampling, 

handling, and analytical procedures, since 

variation in methodology can significantly alter 

nutrient levels measured, Inaccurate management 

decisions will result if acalytical values 

obtained do not accurately reflect the nutrient 

status of the soil or foliage, Key aspects of 

soil and foliage analysis are discussed herein. 

Data are presented to demonstrate the impacts of 

variation in methodology on results obtained. 

Keywords: soil nutrients, foliar nutrients, 

sampling procedures, analytical methods, forest 

trees 

refined discipline. Foresters are only now 

beginning to tap these analyses to their maximun 

potential in forest management. An expansive 

examination of the topic is not possible in this 

forum; however, selected principles of soil and 

foliage analysis are discussed along with some 

factors impacting the utility of these procedures in forestry. 

ANALYTICAL CYCLE 

Both soil and foliage sampling have several 

things in common including what night be called 

the analytical cycle. This cycle includes 

accurate sampling, proper handling of samples, 

accurate analysis, and correct interpretation of 

analytical results. An error at any point 

within the cycle can yield inaccurate results or 

interpretations. 

The first step in the cycle is accurately 

sampling the site conditions of concern. Tbe 

samples collected must be representative of the 

situation that the sampler is interested in 

documenting. For example, if an area of poorly 

growing trees within a stand is of concern, it 

is imperative that the sample collected 

represent the portion of the stand that is 

unhealthy. Samples from healthy areas of the 

stand may also be collected for comparison; 

however, the identity of samples must be 

maintained so that correct comparisons can be 

made. 

After collection, the samples must be properly 

handled until they can be analyzed. Specific 

details of handling are dependent upon analyses 

to he performed, but some general rules apply. 

Soil saolples should be kept in a clean area away 

from fertilizers and other chemicals. Soil is 

usually air dried after collection and prior to 

submission to the laboratory. Foliage samples 

should be dried or frozen as soon after sampling 

as possible. If dried, the saaples should be 

kept dry and in a clean area away from 

contaminating agents. If frozen, foliage should 

be kept totally or partially frozen until 

analyzed, 
The third part of the cycle involves the 

handling and analysis of samples once they 

arrive in the laboratory. Samples nust be 

redried and ground prior to analysis. 

Analytical procedures should be chosen thar 

permit the required interpretations once the 

analysis is completed. Both the methods and 

laboratory quality control standards should be 

well documented. 

Interpretation of results obtained from the 

lab analyses is the final step in the cycle. 

Accurate interpretations are dependent upon 

having results available that accurately reflect 

nutrient status or some other characteristic. 

Evaluation of analytical results cannot be done 

without knowledge of the methods used to analyze 

the samples. 

It is important to remember that the numbers 

themselves are not magical. They have no 

meaning in and of themselves but must be 

interpreted in light of research or operational 

results. The numbers that are ultimately 

interpreted can be altered by an error that 

occurs at any point from selecting the area to 

be sampled through the analysis process. Thus, 

it is imperative that the integrity of the 

analytical cycle be maintained throughout the 

entire process. 

TYPES OF SOIL APSD FOLIAGE ANALYSIS 

Soil 

Chemical analysis generally includes pH, 

organic matter (O.M.), phosphorus (P), potassium 

(K), calcium (Ca), magnesium (Mg), and manganese 

(Mn). Micro-elements determined may include 

aluminum (Al), boron (B), copper (Cu), iron 

(Fe), molybdenum (Mo) , and zinc (Zn). Sulfate 

(SO4-S), nitrate (N03-N), and amonium 

(NH4-N) are other nutrient levels monitored. 

Chemical soil analysis is used to determine the 

need for fertilization, rates of application of 

soil-active herbicides, and nutrient imbalances 

of trees growing on the site sampled. 

Three freqently measured physical traits are 

particle-size analysis (texture), bulk density, 

and moisture-holding capacity. Other physical 

analyses, such as sand fractionation, are less 

frequently measured. Texture analysis is 

required to determine rates of application of 

soil-active herbicides. Bulk density measurements provide indications of potential rooting 

restrictions for new seedlings. Moistureholding capacity can be used to characterize the 

moisture available on specific sites for tree 

growth and development. 

Foliage 

Chemical analysis of foliage generally 

includes nitrogen (N), P, K, Ca, Mg, and Mn. 

Micro-elements determined may include Al, B, Cu, 

Fe, Mo, and Zn. Sulfate is another nutrient 

level monitored in foliage. Chemical foliage 

analysis is normally used to determine the need 

for fertilization (primarily with N and P in 

established forests) or to determine a nutrient 

inbalance that is causing reduced growth or 

unhealthy appearance of seedlings or trees. 

Biochemical analyses can be performed on 

foliage also. These include various sugars, 

starches, carbohydrates, and amino acids, Rapid 

development of new root tissue after planting is 

essential for pine seedling survival, and rout 

elongation early in the growing season is 

dependent upon carb~hydrate reserves stored in 

the roots from the previous growing season 

(Kramer and Kozlowski, 1979)- Management 

activities that increase levels of reserve 

carbohydrates in seedling root systems may 

provide the needed energy source for increased 

root elongation shortly after outplanting and 

thereby increase the seedling's survival 

potential. 

FACTORS IMPACTING ANALYTIC& RESULTS 

Factors that can alter analytical results 

include site history, map unit variability, 

topography, intensity of sampling, and season of 

the year. Factors specific to soils include the 

horizon or depth in the profile to be sampled. 

Location within the crown and the part of the 

leaf to be analyzed are additional factors to 

consider when sampling foliage. The manner in 

which samples are handled and analyzed can have 

significant effects on the results obtained in 

the analysis. 

Site History 

Results obtained cannot be interpreted 

properly without knowledge of the site history, 

Examples of site characteristics that must be 

documented during sampling are the site's 

burning and fertilization history. Soil 

nutrient status can be altered by these two 

practices for long periods, Applications of P 

can be monitored in many soils for years after 

treatment. Repeated fertilizer applications, 

such as are used in seed orchards, can significantly change soil chemistry (Gregory et al., 

1982). Burning large amounts of surface debris 

can have a fertilizing effect because of the 

quantities of nutrients deposited in the ash. 

This is also true when thick organic surfaces 

over mineral soils are burned. 

Comparisons of soil nutrient status before and 

after burning debris piles often reveal large 

differences in the levels of cations present 

(Table 1). A debris pile composed of approximately 60 cu m of pine stens, branches, and 

foliage was burned on a sandy soil (Kaines, 

197th). Burning yielded increased pH as well as 

higher levels of P, K, Ca, and Mg, plus lower 

organic matter concentrations, Over a 3-month 

sampling period, nutrient levels in the 0-2 cm 

zone decreased while those ia Lower zones 

increased, indicating nutrient movement through 

the profile. Post-burning nutrient means were 
substantially larger than those observed prior 

to burning. 

Table 1.--Comparisons of selected nutrient 

concentrations at 3 depths in a soil profile 

before and after burning a debris pile (Haines, 

1978a)a 

Soil Depth pH O.M. P K Ca Mg (X) --------- PPm---------- 

Table 2.--Sample sizes required to estimate mean 

values of soil properties on 2 sites within 5 

percent with 95 percent confidence (Haines and 

Cleveland, 1981) 

Soil Property Old Field Pine & Hardwood 

Bulk density 5 49 

Soil moisture 2 2 616 

Pre-Burn Surface pH 2 2 

Pos t-Burn 

aMeans of 6 observations before burning and 42 

observations over a 3-month period after burning. 

Map Unit Variability and Topography 

Map unit variability will determine the 

location of sample points and also, to some 

extent, the intensity of sampling required to 

obtain acceptable measures of nutrient status. 

Topography is also important in locating sample 

points since nutrient values usually vary with 

topographic position. For example, nutrient 

status on the ridgetop can be lower than that at 

the bottom of the slope because of topsoil 

erosion downslope. Samples should be collected 

only on those portions of the map unit or site 

that are of concern. Inclusions of different 

soil or site conditions should not be sampled. 

For example, small wet depressions, old home 

sites, old roads, or other portions of the site 

that are clearly different from the condition of 

concern should be avoided. If comparisons are 

needed by topographic position, samples from the 

ridge, sideslope, and bottom of the slope might 

be appropriate. 

Sam~ling Intensity 

Intensity of sampling is dependent on site 

variability and on the level of confidence 

required in the results of the analysis. Sample 

sizes required vary considerably depending upon 

characteristics of the site being sampled as 

well as the soil property being measured 

(Table 2). Five forested sites in southwest 

Georgia were sampled monthly for a 1-year period 

to determine the magnitude of variation in 16 

soil properties (Haines and Cleveland, 1981). 

As a part of this examination, the sampling 

intensity required to accurately predict means 

Surface 0. M. 5 2 205 

Surf ace P 7 6 2 2 7 

Surface K 6 9 144 

Surface Ca 9 4 387 

of soil variables was determined. Selected soil 

properties for two of the sites examined are 

included in Table 2. The old-field site is a 

14-year-old slash pine (Pinus elliottii Engelm. 

var. elliottii) plantation on an Orangeburg soil 

(Typic Paleudult: fine-loamy, siliceous, 

thermic). The pine and hardwood site is a 

clearcut mixed pine-hardwood stand that had been 

chopped and burned. The soil is an Esto (Typic 

Paleudult: clayey, kaolinitic, thermic). 

The differences in sampling intensities 

between the two contrasting sites reflect 

differences i n s i t e uniformity. Generally, 

fewer samples are needed on the old-field site 

with its uniform cover of pine canopy and 

absence of understory vegetation. Only pH can 

be measured at both locations with the same 

sampling intensity. 

The variation among soil properties is caused 

by natural variation and by how precisely the 

value can be determined in the laboratory. The 

lowest intensity was for pH, a property that has 

a relatively low natural spatial variation and a 

simple, easily replicated analytical test. 

Higher sampling intensities for the other 

variables reflect a greater range of natural 

variation as well as less precise or 

reproducible analytical procedures. 

Season of Year 

Variation in foliage biochemical compounds and 

nutrient levels throughout the growing season 

has been documented (Kramer and Kozlowski, 1979; 

Wells and Metz, 1963). Concentration variations 

result with reallocation of nutrients and 

biochemical compounds as growth and development 

progress. Foliage sampling to document pine 

nutrition is usually conducted during the 

dormant season when nutrient concentrations are 
most stable. However, some researchers 

recommend sampling during the growing season 

when nutrient demand is greatest. 

Table 3.--Nutrient concentrations in fertilized 

and unfertilized lobolly pine foliage by crown 

position (Haines and Haines, 1979)a 

Less attention has been given to variation in 

soil properties throughout the year. Haines and 

Cleveland (1981) measured selected chemical and 

physical soil properties for 12 consecutive 

months on five forested sites in southwest 

Georgia. Surface bulk density and percent 

moisture, O.M. and K to 20 cm, and P to 10 cm 

varied significantly over time at all 

locations. Soil pH, Ca, Mg, and cation exchange 

capacity to 20 cm and P at 10 to 20 cm differed 

significantly over time at some, but not all, 

sites. The authors concluded that periodic 

variation must be considered when effects of 

forest management and research treatments on 

soil chemical and physical properties are 

evaluated. 

Crown Position and Leaf Portion 

Nutrient composition of tree foliage is known 

to vary with age of foliage and position within 

the crown (Madgwick, 1964; Wells and Metz, 

1963). Application of 198 kg-N/ha, 7 kg-P/ha, 

and 26 kg-K/ha over a 2-year period significantly increased loblolly pine (Pinus taeda L.) 

foliar N concentrations but not P or K (Haines 

and Haines, 1979). Nitrogen concentrations were 

significantly higher in fertilized loblolly pine 

foliage regardless of the portion of the crown 

sampled (Table 3). Rates of P and K fertilization apparently were too low to affect concentrations of those nutrients in foliage. Since 

operational fertilization decisions are tied to 

foliar N levels, sample location within the 

crown can determine whether or not prescriptions 

are accurately developed. 

When determining nutrient status of broadleaf 

species, one must decide which portion of the 

leaf to analyze. Analysis of specific portions 

of leaves of agronomic and horticultural crops 

has been common for decades (Bould, 1961; Kwong 

and Boynton, 1959; Goodall and Gregory, 1947). 

Variation of nutrient concentrations by leaf 

portion has been documented for some forest tree 

species such as yellow poplar, Liriodendron 

tulipefera L. (Auchmoody, 1974; Finn, 1966), as 

well as sycamore maple, Acer pseudoplatanus L., 

and European horsechestnut, Aesculus 

hippocastanum L., (Guha and Mitchell, 1965). 

Haines et al. (1979) compared nutrient 

composition of sycamore (Platanus occidentalis 

L.) blades, petioles, and whole leaves. 

Nitrogen was highest in the blade and lowest in 

the petiole; when the whole leaf was analyzed 

the higher concentration in the blade was 

diluted by lower petiole-N levels (Table 4). 

Petiole-P and K were both significantly higher 

than levels in other leaf parts; petiole-Ca was 

significantly lower. Given the magnitude of 

nutrient concentration variation, it is unlikely 

that one leaf portion could be selected to most 

accurately reflect sufficiency or deficiency for 

all nutrients of interest. 

Crown Position N P K 

------------pet-------------- 

Check Trees 

Upper 0.97 6.13 0.81 

(0.09) (0.02) (0.07) 

Middle 0.78 0.11 0.43 

(0.07) (0.03) (0.05) 

Lower 0.69 0.10 0.31 

(0.09) (0.04) (0.04) 

Fertilized Trees 

Middle 0.89 0.11 0.46 

(0.07)" (0.03) (0.06) 

Lower 0.91 0.09 0.40 

(0. LO)** (0.02) (0.05) 

aMeans of 4 check and 4 fertilized trees; 

standard errors of the mean in parenthesis. 

* denotes significance at the .05 level; **, at 

the .O1 level. 

Table 4.--Nutrient concentrations in sycamore 

foliage by leaf part (Haines et al., 1979)a 

Leaf Part N P K C a 

-------------pet-------------- 

Whole Leaf 1.82 y 0.12 x 0.80 y 0.95 y 

Blade 2.10 z 0.12 x 0.71 x 0.96 y 

Petiole 0.62 x 0.16 y 1.22 z 0.85 x 

aMeans followed by different letters are 

significantly different at the .05 level. 

Correlation of nutrient concentrations with 

broadleaf tree growth presents similar problems 

(Table 5). Haines et al. (1979) determined 

correlation coefficients between nutrient concentrations by leaf part and sycamore height and 

volume growth. Blade-N was the most highly correlated with height and volume growth of all 

nutrients. Blade-P and K were both more highly 

correlated than petiole or whole leaf concentrations. For height growth, blade-N was the best 

single variable predictor while blade-P was the 

best for volume growth. 
Sample Handling Table 6.--Effects of handling procedures on 

slash pine foliage concentration (Anonynious, 

Nutrient levels in pine foliage can be used as 1976)a 

indicators of the need for operational fertilization of established stands (Pritchett, 1979; 

Wells et al., 1973). When foliar nutrient 

levels are below established critical values, 

fertilization will likely result in an increase 

in tree growth. The analytical values obtained 

are dependent upon the actual nutrient content 

Sample Handling K P K 

~reatment~ ------- PC t---------- 

Ice + Dry 0.82 0.077 0.35 

Table 5.--Correlation coefficients between Ice + Refrigerate f Dry 0.84 0.078 0.35 

sycamore foliage nutrient concentrations and 

height and volume growth (Haines et al., 1979)a Ambient + Dry 0.81 0.075 0.34 

Ambient +Refrigerate + Dry 0.85 0.079 0.35 

~lement/Leaf Part Height Growth Volume Growth 

Ambient + Store + Dry 0.91 0.082 0.38 

Nitrogen 

Blade 

Petiole 

Whole Leaf 

"Means of 4 observations 

b~ce = 5 hrs in ice chest; dry = 24 hrs at 60' 

C; refrigerate = 10 days at 5' C; ambient = 5 

hrs at 16' 6; store = 10 days at 21° C. 

Phosphorus 

Blade 

Petiole 

Whole Leaf Another alternative handling procedure is to 

freeze samples until they can be analyzed. A 

trial was established to determine whether or 

not foliage samples could be frozen prior to 

drying without altering nutrient concentrations 

obtained when the samples were analyzed. 

Thirty-six samples were collected and divided in 

half. One-half of each sample was frozen for 2 

weeks after collection, thawed, dried, and 

ground. The other half was dried immediately 

after collection and then ground. All samples 

were analyzed at the same time. Paired t-tests 

indicated that N, Ca, Al, and Cu concentrations 

differed significantly by treatments (Table 7). 

Potassium 

Blade 0.29 0.48** 

Petiole 0.23 0.31 

Whole Leaf 0.12 0.13 

a** denotes significance at the .05 level. 

and the oven-dry weight of the foliage sample. 

Since the results are expressed as a percentage 

of oven-dry weight, it is imperative that no 

changes occur in the weight of the sample from 

sampling to analysis. Weight losses can occur 

if respiration continues in the sample prior to 

oven-drying. Obviously, the situation is quite 

important when the foliar concentrations are 

close to the critical levels where a relatively 

small difference in the results could influence 

the decision to fertilize. Attempts have been 

made to document the kinds of changes in 

nutrient levels that result with different 

sample treatments. 

Table 7.--Comparison of effects of freezing on 

N, Ca, Al, and Cu concentrations in loblolly 

pine foliagea 

Element Dried Frozen 

In one study, the staff of the Cooperative 

Research in Forest Fertilization (CRIFF) program 

at the University of Flordia tested five 

different handling procedures (Anonymous, 

1976). Storing samples at ambient temperature 

at collection plus 10 days storage at room 

temperature resulted in increased N and K levels 

in slash pine foliage (Table 6). This apparently was a result of dry-weight loss from 

continued respiration prior to drying. Extended 

refrigeration following sample collection 

affects P levels more than other elements. The 

conclusion reached in this study was that the 

safest way to handle foliage samples after 

collection is to keep samples on ice or in a 

refrigerator until they can be dried. Drying 

should occur as soon after collection as 

possible. 

A1 (ppm) 404 

(22 

apleans of 36 observations; standard errors of 

the mean in parenthesis. ** denotes 

significance at the 0.01 level. 

The difference in N levels had the most 

serious implications because decisions on 
operational fertilization are made on the basis 

of foliar N levels. If sample handling causes N 

levels to be higher than they should be, stands 

that night respond to N fertilization would be 

eliminated from the program because the N 

concentrations are above critical levels. 

Similarly, if S levels are lowered by sample 

handling, stands might be fertilized that are 

not actually economically responsive. 

A follow-up trial was conducted to deternine 

if duration of freezing impacted results 

obtained. Samples were either oven dried only, 

frozen one week and oven dried, or frozen 2 

weeks and oven dried. Both freezing treatments 

significantly altered the K, P, and Mn levels 

obtained (Table 8). Since freezing can alter 

both N and P results obtained, operational 

foliage samples should not be frozen. Critical 

levels for bi and P fertilizer response were 

established using oven dried samples, and 

reliable correlations between frozen and oven 

dried samples have not been established. 

Table 8.--Effects of freezing duration on N, P, 

Mn, and Zn concentrations of loblolly foliagea 

Treatments N P Mn Z n -------------pet----------- PP" 

Dried 1.22 x 0.101 x 0.021 x 33.5 x 

(0.013) (0.001) (0.002) (1.1) 

Frozen 1.17 y 0.095 y 0.024 y 35.9 y 

1 week (0.013) (0.001) (0.001) (1.3) 

Table 9.--Effect of drying method on loblolly 

pine nutrient concentrationsa 

Drying N P K 

Met hod ------------pet----------- 

Forced-Air 1.16 0.096 0.23 

(0.013) (0.002) (0.014) 

Microwave 1.15 0.095 0 -24 

(0.014) (0.004) (0.008) 

aMeans of 36 observations; standard errors of 

mean in parenthesis. 

King and Haines (1979) examined the effects of 

mechanical thinning equipment on soil bulk 

density at 2 depths in a loamy Coastal Plain 

soil. Thinning had no effect on bulk density at 

either 5 cm or 10 cm depths (Table 10). In this 

same study, 2 methods of measuring bulk density 

(gravimetric and neutron probe) were compared. 

The gravimetric method requires collection of a 

known volume of soil, oven-drying, and 

calculation of the bulk density. Bulk density 

has traditionally been measured by the 

gravimetric method. The neutron probe measures 

density in place in the soil as a function of 

neutron scatter, and the value is read on the 

inst rumenti 

Table 10.--Comparison of 2 methods of 

determining bulk density at 2 depths before and 

after thinning (King and Haines, 1979)a 

Frozen 1.15 y 0.097 y 0.024 y 34.1 xy 

2 weeks (0.013) (0.001) (0.002) (1.2) 

Met hod Bef ore Thinning After Thinning 

5 cm 10 cm 5 cm 10 cm 

aMeans of 36 observations; standard errors of 

mean in parenthesis. Methods by element 

followed by different letters differ 

significantly at the 0.05 level. 

Standard foliage drying procedures involve use 

of forced air drying ovens that are not always 

readily available to foresters who collect 

operational foliage samples. Since microwave 

ovens are widely available, a trial was 

conducted TO compare nutrient concentrations 

obtained following conventional forced-air and 

microwave drying (Table 9). No significant 

differences in loblolly pine foliar M, P, or K 

concentrations were observed that would prevent 

use of microwave drying. 

Instrumentation and Analytical Techniaues 

Variation in results is expected depending 

upon the instrumentation and the analytical 

technique utilized. Instruments and techniques 

used must be carefully documented so that the 

results can be interpreted correctly. Comparisons among methods of analysis have been nade 

for some soil determinations. 

Gravimetric 1.54 1.62 1.50 1.66 

(0.09) (0.10) (0.14) (0.08) 

Neutron 1.21 1.29 1.27 1.34 

Probe (0.08) (0.06) (0.06) (0.06) 

aMeans of 14 observations; standard deviations 

in parenthesis. 

The neutron probe consistently underestimated 

density when compared to the gravimetric 

method. Standard deviations from the mean were 

greater with the gravimetric method than with 

the neutron probe. This is attributed to more 

direct measurement of density with the probe as 

compared to the handling, weighing, drying, and 

calculations required for the gravimetric 

method. Generally speaking, the more mechanized 

a method the more precise it is likely to be. 
As a part of our laboratory research program, 

we have done extensive work comparing extractants for soil analysis across soil types on our 

land, Data presented (Table 11) were obtained 

from the A horizon of a wet, loamy sand soil in 

the Atlantic Coastal Plain known to be moderately responsive to P fertilization at stand 

establishment. Following extraction, P was 

determined by a modified vanadomolybdate method 

(Chapman and Pratt, 1961); A1 and Fe were 

determined by atomic absorption spectrophotometry. 

Table 11.--Comparison of P, Al, and Fe 

concentrations in the A horizon determined 

following five different extractionsa 

Extractant P A1 Fe em-------- ppm---------- 

Double Acid 3.3 

(0.2) 

Mehlich I + Flourine 4.5 

(0.3) 

Mehlich I1 4.2 

(0.2) 

Strong Bray 3 9 

(2.2) 

Weak Bray 

aMeans of 24 observations; standard errors of 

the mean in parenthesis. 

The most dramatic difference is with the 

Strong Bray extractant that measures from 7 to 

12 times as much P as the other extractants. 

Extractants rank the same for A1 as for P, but 

the differences are only 2 to 4 times as large. 

Iron does not follow the same pattern as P and 

Al. Fertilizer recommendations on wet coastal 

plain soils are often made on the basis of soil 

P levels. Obviously, it is imperative to know 

the extractant used to obtain results being 

examined. More research is also needed to 

determine correlations of fertilizer response 

with results of different extractants, since 

response was usually correlated with only one 

extractant. 

Attempts were made to correlate loblolly pine 

foliage P concentrations with soil P levels 

determined following the same five soil 

extractions. Correlation analysis was used to 

relate soil-P levels obtained with foliar P 

concentrations. Soil samples were collected 

from the surface, upper subsoil, and lower 

subsoil beneath the crown of the tree from which 

the foliage sample was collected. The highest 

correlation observed was in loblolly stands less 

than l5 years old in the lower subsoil for the 

Mehlich I + Flourine extractant (0.523 **). 

In the same study, correlations between soil 

A1 and Fe levels and foliar P levels were 

examined. Both soil Al and Fe levels in the 

surface horizon were significantly correlated 

with foliar P for all five extractants. Highest 

correlation for soil A1 was with the Mehlich I + 

Flourine extractant (0.649 A*). The highest 

correlation for soil Fe was a negative one with 

the Weak Bray extract (-0.720 **). 

MTAGEMENT IMPLICATIONS 

The utility of soil and foliage analysis has 

been demonstrated; however, foresters still have 

ample opportunity to refine the use of these 

procedures. More in-depth knowledge of how 

various nutrient levels relate to site productivity and tree health and vigor is required for 

better utilization of the technology. Clearer 

understanding of the total nutrient cycle in 

forested ecosystems will help foresters more 

accurately interpret analytical results. 

Standardization of collection, handling, and 

analytical procedures will make interpretation 

of results obtained more reliable. Examples 

presented herein have demonstrated that variation in any of the procedures can alter the 

results obtained. Such variation is particularly troublesome when results obtained are 

near critical levels that indicate nutrient 

sufficiency or deficiency. For example, foliage 

analysis results may indicate that an N or P 

deficiency exists and that operational fertilization can provide an economically attractive 

growth increase. However, if those results do 

not accurately reflect the nutrient status of 

the site in question, a bad decision will be 

made. 

Standard procedures will also help us to 

develop a body of analytical knowledge that is 

comparable and more widely applicable in forest 

management. It may be too much to hope for one 

standard procedure to be accepted throughout the 

discipline, but it is a worthy goal to strive 

toward. At the least, researchers must become 

much more adept at interpreting results. 

Correlations among different techniques must be 

identified so that accurate interpretations can 

be made. Additionally, unless such correlations 

exist, we will be unable to fully utilize 

information that is already in the literature. 

Henry George (Wahlenberg, 1960) noted, "Until 

there is correct thought there cannot be correct 

action." Correct thought is based on information. Incorrect thought stems less from a 

scarcity of information than from its relative 

inaccessibility. Information overload is often 

more of a problem today than a lack of data. It 

is imperative that pertinent information on soil 

and foliage analysis be readily accessible in 

easily understandable form for decision makers. 
The assistance of Craig Turner, Chris Nelson, 

and Mona McCranie in preparing the visuals for 

the oral presentation and the manuscript is 

gratefully acknowledged. 

LITERATURE CITED 

Anonymous. 1959. Mineral nutrition of trees: a 

symposium. Duke Univ. School of Forestry 

Bull. No. 15. 

Anonymous. 1968. Forest fertilization: theory 

and practice. Tennessee Valley Authority, 

Knoxville. 306 pp. 

Anonymous. 1976. Nutrient levels and 

deficiency symptoms in pine -- operational 

sampling methods. CRIFF Progress Rept. Univ. 

Florida, Gainesville, p. 102-104. 

Auchmoody, L. R. 1974. Nutrient composition of 

blades, petioles, and whole leaves from 

fertilized and unfertilized yellow-poplar. 

USDA Forest Serv. Res. Note NE-198. 5 pp. 

Bauer, H. 1910. Stoffbildung und stoffaufnahme 

in jungen nadelholzern. Zeitsch Forst. Landw. 

8:457-498. 

Bengtson, G. W. 1979. Forest fertilization in 

the United States: progress and outlook. 

Journal of Forestry 78:222-229. 

Bould, C. 1961. Leaf analysis as a guide to 

the nutritional status of soft fruit crops. IN 

Plant analysis and fertilizer problems 111. 

AIBS, Washington, D.C. p. 3-15. 

Chapman, H. D. 1966. Diagnostic criteria for 

plants and soils. Univ. California, 

Riverside. 793 pp. 

Chapman, H. D. and P. F. Pratt. 1961. Methods 

of analysis for soils, plants, and waters. 

Div. Agric., Univ. California, Riverside. 309 

PP 

Finn, R. F. 1966. Mineral nutrition of 

yellow-poplar (Liriodendron tulipifera L. ) . Ph.D. Diss. Dept. Forestry, Michigan State 

Univ. Diss. Abstr. No. 17109-B, p. 2998. 

Goodall, D. W. and F. G. Gregory. 1947. 

Chemical composition of plants as an index of 

their nutritional status. Imperial Bureau 

Horticultural and Plant Crops Technical 

Communication No. 17. 167 pp. 

Gregory, J. D., W. M. Guinness, and C. B. 

Davey. 1982. Fertilization and irrigation 

stimulate flowering and cone production in a 

loblolly pine seed orchard. Southern Journal 

of Applied Forestry 6:44-48. 

Guha, PI. M. and R. L. Kitchell. 1965. The 

trace and major element composition of leaves 

of some deciduous trees. I. Sampling 

techniques. Plant and Soil 23:323-338. 

Haines, L. W. and S. G. Haines. 1979. 

Fertilization increases growth of loblolly 

pine and ground cover vegetation on a Cecil 

soil. Forest Science 25:169-174. 

Haines, S. G. i978a. Changes in soil nutrient 

contents under an ash pile. International 

Paper Co. Research Letter KO. 33. 6 pp. 

Haines, S. G. 1978b. Implications of biome 

research for industrial forestry. Proc. 

Society of American Foresters National 

Convention, St. Louis, 110. p. 115-116. 

Haines, S. G., L. W. Haines, and G. White. 

1979. Nutrient composition of sycamore 

blades, petioles, and whole leaves. Forest 

Science 25:154-160. 

Haines, S. G. and G. Cleveland. 1981. 

Seasonal variation in properties of five 

forest soils in southwest Georgia. Soil 

Science Society of America Journal 

45: 139-143. 

King, T. and S. G. Haines. 1979. Soil 

compaction absent in plantation thinning. 

USDA Forest Serv. Res. Hote SO-251. 4 pp. 

Kramer, P. J. and T. T. Kozlowski. 1979. 

Physiology of woody plants. Academic Press, 

New York. 811 pp. 

Kubler, W. 1912. Die periodizitat der 

nahrstoffaufnahme und trockensubstanzbildung 

von zweijahrigen buchen. Naturw. Zeitschr. 

Forst. Landw. 10:161-187. 

Kwong, S. S. and D. Boynton. 1959. Time of 

sampling, leaf age, and leaf fraction as 

factors influencing the concentrations of 

nutrient elements in strawberry leaves. 

American Society Horticultural Science 

73: 168-173. 

Madgwick, B. A. 1. 1964. Variations in 

chemical composition of red pine (Pinus 

resinosa Ait.) leaves: a comparison of 

well-grown and poorly-grown trees. Forestry 

67 :87-94. 

Pritchett, W. L. 1979. Properties and 

management of forest soils. John Wiley G 

Sons, Eew York. 500 pp. 

Pritchett, W. L. and J. Gooding. 1975. 

Fertilizer recommendations for pines in the 

southeastern coastal plain of the United 

States. Fla. Agr. Exp. Stn. Bull. No. 

774. 23 pp. 
Wahlenberg, W. G. 1960. Loblolly pine: its 

use, ecology, regeneration, protection, 

growth and management. School of Forestry, 

Duke Univ., Durham, N.C. 603 pp. 

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 Science Society America 

Proceedings 27:90-93. 

Wells, C. G., D. M. Crutchfield, K. PI. 

Berenyi, and C. B. Davey. 1973. Soil and 

fo1iar guidelines for phosphorus fertilization of lobloily pine. USDA For. Serv. 

Res. Pap. SE-110. 15 pp. 
Tropical Forests and the Global Carbon cycle1 

Sandra J3rown2 

Abstract.--The uncertainty about the role of 

tropical forests in the global cycle is due to 

many factors, including problems of estimating 

(1) forest biomass, (2) losses of soil carbon 

from forest clearing, and (3) rates of wood 

decomposition. Estimates of biomass of tropical 

forests based on extensive forest volume data 

give significantly lower values than estimates 

based on direct measurement methods. A major 

source of error in converting commercial volumes 

to total biomass is the high variability in the 

expansion factors (ratio of total biomass to 

commercial biomass) that suggests a need for 

regional estimates rather than for highly aggregated ones as has been done in the past. Loss 

rates of soil organic carbon upon conversion of 

forests to agriculture are influenced by the type 

of agriculture practice (small loss to small gain 

for pastures versus about 40 percent loss for 

crops), soil texture (less loss from clay soils), 

climate, and time. Decomposition rates of woody 

debris of primary forest species are slow (average decomposition coefficients of 0.02-0.07 yr-1) 

and are partially regulated by the chemical 

characteristics of wood. These decomposition 

rates are slower than rates of forest regrowth 

and create carbon sinks in logged and natural 

forests. Further research is still needed to 

refine some of these carbon storages and fluxes 

to improve our understanding of the carbon cycle 

of tropical forests. 

Keywords: Biomass, carbon cycle, soil carbon, 

tropical forests, wood decomposition. 

Clearing of tropical forests for agriculture 

has the potential of producing a source of C02 to 

the atmosphere and thus exacerbating the potential "greenhouse effect". The release of C02 

from clearing tropical forests for agriculture is 

due to burning and decomposition of plant material and the increased oxidation of soil organic 

matter. Results from models have demonstrated 

that land use changes in tropical forests produce 

a source of atmospheric C02 that may be as much 

as 20-80 percent of the amount contributed by the 

burning of fossil fuel (Houghton and others 1983, 

Detwiler 1986). These estimates of carbon flux 

(as C02) to the atmosphere are derived from 

models that consider rates of forest clearing, 

specific land uses for which an area is cleared 

(e.g., for permanent agriculture, shifting agriculture, pasture, or timber), and changes in 

biomass or carbon content of the vegetation and 

soil due to clearing. 

There are several sources of error associated 

with the estimates of carbon flux from tropical 

forests. These errors are based based mainly on 

lpresented at the Symposium on Current Topics in 

Forest Research Emphasis on Contributions by 

Women Scientists , November 4-6, 1986, 

Gainesville, FL. 

2~ssociate Professor, Department of Forestry, 

~niversity of Illinois, 110 Mumford Hall, 1301 W. 

Gregory Dr., Urbana, IL 61801. 

uncertainties in the value of the parameters used 

in models such as: the biomass or carbon content 

of tropical forests that are being cleared, the 

rates of forest clearing by forest type (i.e., 

low or high biomass forest), changes in soil 

carbon pools upon clearing, and rates of 

decomposition of organic material left behind on 

the site after clearing. The objectives of this 

paper are to discuss some of the sources of error 

associated with estimating (1) the carbon content 

of tropical forests, (2) changes in the carbon 

content of tropical soils due to forest 

conversion, and (3) decomposition rates of 

tropical woody debris. 

CARBON CONTENT OF TROPICAL FOREST VEGETATION 

Because of the diversity of forest types in the 

tropics, the problems of estimating their carbon 

content with any degree of precision are enormous. 

According to the Holdridge Life Zone system 

(Holdridge 1967) for classifying plant formations 

of the world, a system based on mean annual biotemperature and precipitation, there are 30 

unique forested life zones in the tropics ranging 

from lowland very dry forests to montane rain 

forests. Each of these forested life zones potentially has a different organic carbon content 

because of the influence of temperature and moisture on structure and function of forests 

(Holdridge 1967). Brown and Lugo (1982) synthesized existing data on the carbon content of tropical forests and found that there was a highly 
significant relationship between carbon content 

of vegetation (expressed as biomass) and an index 

of life zone (ratio of temperature to precipitation; Fig. I). Carbon content of tropical 

forests peaks in the moist forest life zone 

(T/P=0.7-1.4 x with lower values in wetter 

(TIP (0.6 x and drier (T/P >2.0 x 10-2) 

life zones. Thus, models of tropical forest 

clearing need information on the kinds of forest 

being cleared because their carbon content is 

related to the climate in which they grow. 

Unfortunately, this kind of information is 

lacking and represents a source of error in 

carbon flux estimates. 

600 

- 500 

. 

- 400 

.: 500 

m 

- 

0 0 zoo 

tye 596 +478 log X- 224 1 

8 

Figure 1.--Relationship between total biomass of 

tropical forest vegetation and the ratio of temperature to precipitation (T/P), a ratio used as 

an index of life zone (see text for further explanation). This relationship was determined by 

least squares regression analysis and is significant at p=0.05 with an r2=0.54 (from Brown and 

Lug0 1982). 

Another uncertainty in the data base for tropical forests is the magnitude of the carbon content of tropical forest vegetation. There have 

been several attempts during the last decade to 

both estimate the carbon pool in tropical forests 

and compute a weighted average carbon density 

(Table 1). The first four values in Table 1 are 

based on a summary of the published ecological 

literature. Variation in the estimates of the 

size of the carbon pool is attributed to both 

differences in the area of tropical lands covered 

by forests and differences in the carbon content 

of tropical forest vegetation. The changes in 

the amount of tropical forests used in these 

studies reflect improved accuracy in the area 

estimates by the international organizations 

charged with such assessments (e.g., Food and 

Agriculture Organization of the United Nations 

[FAo]) rather than a real decrease in forest area. 

Differences in the carbon content of forests used 

in the studies able 1) are due to (1) grouping 

of forests into fewer or more categories (e.g., 

two main types were used by Whittaker and Likens 

El9731 whereas six main types were used by Brown 

and Lugo [19823) and (2) accessibility to a 

larger data base in the later studies (e.g., many 

studies used by Brown and Lugo were published 

after 1975). It is generally agreed by those 

working with the global carbon cycle that the 

lower estimates, based on the ecological literature, of Brown and Lugo (1982) and Olson and 

other (1983) are more representative of the 

carbon content of tropical forests. 

Table 1.--Estimates of carbon content in tropical 

forest vegetation 

Carbon 

Area Carbon content (t/ha) poo 1 

Weighted 

( 106ha) Range average ( 1015g 

aWhittaker and Likens 1973 

b~jtay and other 1979 

CBrown and Lugo 1982 

d~lson and others 1983 

eBrown and Lugo 1984 

Brown and Lugo (1984) made another estimate of 

the carbon content of tropical forests using commercial volumes. This study relied heavily on 

the FA0 (1981) report in which average commercial 

volumes for eight forest types in 76 tropical 

countries were given. Commercial volumes were 

converted to total biomass of vegetation by multiplying volume by an average wood density to obtain commercial biomass and then by an expansion 

factor (ratio of total above and below ground 

biomass to commercial biomass); biomass was converted to units of carbon (assuming 1 gram of 

organic matter = 0.5 gram of carbon). (Details 

of the analysis are given in Brown and Lugo 

[1984].) This analysis resulted in a carbon pool 

and weighted carbon density of tropical forest 

vegetation of about one-half the values based on 

direct measurements given in the ecological 

literature able 1). 

One of the major causes of the discrepancy 

between ecological-based and volume-based biomass 

estimates is due to sampling error. Biomass estimates derived from the ecological literature are 

based on direct measurements (either by harvest 

methods or allometry) of small areas (a total of 

< 30 hectares for all studies) of a few tropical 

forest types and extrapolated to all tropical 

forests. Volume-derived biomass estimates are 

based on large sample areas (hundreds to thousands of hectares) and tend to be a more representative sample. Selection of small sample 

plots for ecological studies of direct measurements may be biased towards large biomass plots 
because of a preconceived notion as to what a 

tropical forests should look like. For example, 

a frequency distribution of volume-derived biomasses for tropical moist forests of the Amazon 

basin demonstrate that more than 50 percent of 

the area covered in the survey had biomass values 

less than 200-220 metric tonne per hectare (t/ha) 

(Fig. 2). Biomasses of tropical American forests 

obtained from destructive sampling or allometric 

methods ranged from 210-480 t/ha (~rown and Lugo 

1982), of which 50 percent had values between 

210-330 t/ha and the other 50 percent were between 370-480 t/ha, with a greater frequency at 

the high end of the range. These results suggest 

that biomasses obtained by direct measurement on 

a few hectares are not average for Amazonian tropical moist forests but are biased towards high 

biomass plots. Similar trends were obtained for 

forests in tropical Africa and Asia (~rown and 

Lug0 1984). 

There are several potential sources of error in 

biomass estimates based on volume: wood densities, stand volumes, and expansion factors. Of 

these, the greatest error is likely to exist in 

the expansion factors, and the determination of 

new factors is the emphasis on my current research (in cooperation with Ariel Lugo). New 

expansion factors are being determined from 

detailed forest plot data which include diameters, species, and commercial volumes of individual trees in the plots and specific gravities of 

the species. From this information commercial 

biomass was calculated (sum of the product of 

commercial volume and specific gravity of all 

trees). All the available allometric data for 

tropical trees have been gathered (from the literature and personal records from collegues) and 

allometric regression equations developed. These 

allometric regression equations were then used to 

calculate aboveground biomass of the plots for 

which commercial biomass was calculated. Root 

biomass was determined from root/shoot ratios 

given in Brown and Lugo (1982). Expansion factors were calculated as total biomass/commercial 

biomass. Results of this analysis to date are 

shown in Table 2 and are compared to the expanTable 2.--Expansion factors for converting tropical forest volumes to total biomass 

Expansion Factor Sample 

Forest type Range Mean size 

Closed humid 

forestsalb 1.3-1.8 1.6 19 

Open fores ta : 2.7-3.1 2.9 2 

Moist forest: 1.0-1.7 1.3 10 

Wet and rain forests: 1.9-2.4 2.2 5 

Dry forests : 3.6-3.7 3.7 2 

aFrom Brown and Lugo 1984 

b~his category includes moist, wet, and rain 

forests 

Biomass Class (t/ha) 

Figure 2.--Frequency distribution of volumederived biomasses based on volume data collected 

from 1230 x 1 hectare plots of forests in the 

Amazon Basin (from Brown and Lugo 1984). 

sion factors used by Brown and Lugo (1984) in 

their earlier volume-derived biomass estimates. 

Differences between the earlier and present 

efforts are clearly evident; however, the present 

effort has not been completed and it remains to 

be seen how significant these changes will be. 

In conclusion, use of forest volume data offers 

an advantage over ecological biomass data because 

larger areas of tropical forests are represented 

and a more realistic picture of the variability 

in forest biomass is provided. Revised expansion 

factors appear to be more variable than the previous analysis (Brown and Lugo 1984) suggested and 

demonstrate the need for regional biomass estimates rather than aggregated ones. A comparison 

of the new expansion factors (Table 1, based on 

the analysis to date) with those obtained by 

Brown and Lugo (1984) suggest that volume-derived 

biomass estimates of tropical forests could 

change by as much as plus/minus 40 percent. 

CHANGES IN SOIL CARBON CONTENT FROM FOREST 

CONVERSION 

The goal of this phase of my research was to 

determine the changes in organic carbon content 

of soil due to conversion of tropical forests to 

agriculture. This was accomplished by sampling 

soil from a chronosequence of agriculture sites 

of known age and comparing their carbon content 

to that of a nearby forest site, controlling for 

such factors as slope, elevation, and soil texture. Sampling was accomplished in a variety of 

life zones in tropical America (~uerto Rico, U.S. 

Virgin Islands, Costa Rica, and Venezuela). 

Because most of the forest conversion was to pasture, sampling was concentrated in this practice, 

(Harmon and others 1986). LITERATURE CITED 

Other studies of wood decomposition in the 

tropics obtained decomposition coefficients of 

0.11-0.46 year-I iOdum 1970; Kira 1978; Lang and 

Knight 1979), values that are about an order of 

magnitude greater than those that I obtained, 

The reasons for these differences remain to be 

determined. Preliminary results from the analysis of extractives, lignin, and nitrogen contents 

demonstrate that the slow decoqosing woods have 

high concentrations of extractives and lignin and 

low nitrogen. Greater understanding of rates of 

wood decomposition in the tropics will be gained 

when the influence of wood chemistry as well as 

climate on this process are investigated, 

Table 3.--Decomposit ion coefficients (yr-l) for 

woody debris (model: y=e-kt) of eight tropical 

species. 

Size class (cm) 

10-20 20-30 30-40 >4 0 

n 6 5 4 2 

Range 0.006 - 0.016 - 0.004 - 0,012 - 0.130 13.115 0.075 8.026 

Mean 0,068 0.058 0.040 0,019 

CONCLUSIONS 

Much of the previous understanding of the carbon cycle in tropical forests lands contained 

many misconceptions including: all tropical forests have high biomasses, conversion to agriculture results in high losses of soil carbon, and 

decomposition of all organic materials occur at 

fast rates. Incorporation of the results from my 

research and from the research of others into 

carbon models of tropical forests have lowered 

estimates of their contribution to atmospheric 

C02 from a value almost equal to that from the 

burning of fossil fuels (e,g,, Houghton and 

others 1983) to a value equal to about 20 percent 

of that from burning fossil fuels (~etwiler 1986). 

Progress has clearly been made in improving our 

understanding sf the carbon cycle in tropical 

forests, however results from research also demonstrate how much more there still is to learn 

about this cycle in the tropics, 

The author thanks Ariel Lugo who cooperates 

with her in this study, and Jon Chapman for his 

assistance with calculation of biomass expansion 

factors, This work was supported under subcontract 19B-07762C with the author and Martin 

Marietta Energy Systems Inc,, of contract 

DE-AC05-840R21400 with the U.S. Department of 

Energy, 

Ajtay, Gel,,; Ketner, P,; Duvignead, P, 

Terrestrial primary and phytornass. 

In: Bolin, Be; Degens, E,T,; Kempe, S,; Retner, 

P,, eds. The global carbon cycle, New York: 

John Wiley and Sons; f979:L29-182, 

Brown, S.; Luge, A.E. The storage and production 

of organic matter in tropical forests and their 

sole in the global carbon cycle, Biatropica 

14:161-184; 1482, 

Brown, S,; L~go, A,E, Biomass of tropical forest: 

a new estirna~e based on forest volumes, Science 

223:1290-1293; 1984, 

Bultman, J,D,; Southwell, C,R, Narural resistance 

of tropical herican woods to terrestrial wooddestroying organisms, Biotropica 8:71-95; 1976. 

DetwiLer, R,P. Land use change and the global 

carbon cycle: the role of tropical soils, 

Biogeochernistry 2:67--93; 1986, 

Food and Agriculture Organization, Los recursos 

forestales de la America tropical; Informe 

Tecnico 1; Forest resources of tropical Asia; 

Technical Report 2; Forest resources of tropical Africa; parts 1 and 2; Technical Report 3, 

Rome, Italy: FAO; UN 32/6.2301-78-04; 3 volumes; 1981, 

Harmon M-E,; Franklin, J.F,; Swanson, F,J* [and 

others], Ecology of coarse woody debris in 

temperate ecosystems, Advances in EcoEcogicaL 

Research L5:113-302; 1986, 

Holdridge, L,R, Life zone ecology, San Jose, 

Costa Rica: Tropical Science Center; 1967, 206 

PI' * 

Ksughton, R.A,; Hsbbie, J.E,; MelibPo, J,M. [and 

others], Changes in the carbon content of terrestrial biota and soils between 1860-1980: a 

net release of CB2 to the atmosphere, 

Ecological Monographs 53:235-262; 1983. 

Kira, T, Cornunity architecture and organic matter dynamics in tropical lowland rain forests 

of southeast Asia with special reference to 

Pasoh Forest, West Malaysia, In: Tomlinson, 

P,B,; Zimerman, M,H,, eds, Tropical trees as 

living systems, New York: Cambridge University 

Press; 1978:561-590, 

Lang, G.E,; Knight, B,H, Decay rates for boles of 

tropical trees in Panama, Biotropica 

11:316-317; 1979. 

Odum, N,T, Sumary: and emerging view of the 

ecological system at EL Verde. In: Odum, R,T.; 

Pigeon, R.F., eds, A tropical rainforest, 

Springfield, VA: National Technical information 

Service; TLD-24240; 1970: chapter 1-10, 

Olson, J,S,; Watts, J,A,; Allison, L,3, Carbon in 

Live vegetation of major warEd ecosystems, 

Springfield, VA: National Technical Information 
Service; DoE/WBB-0037; 1983. 152 pp. 

Sanchez, P.A. Properties and management of soils 

in the tropics. New York: John Wiley and Sons; 

1976. 130 pp. 

Whittaker, R.R.; Likens, G.E. Carbon in the 

biota. In: Woodwell, G.M.; Pecan, E.V., eds. 

Carbon and the biosphere. Springfield, 

Virginia: National Technical Information 

Service; CONF-720510; 1973:281-302. 
Xylem Sap Technology: A New Frontier in 

Forestry Research 1 

This report surveys the development of soil 

and plant chemical analysis for mineral nutrients 

and explores the potential of xylem sap analysis 

for problem solving in forestry. 

The field of forest soil chemistry has developed 

slowly, drawing heavily on the methods used in 

agricultural soil chemistry. Scientists have 

acknowledged the deficiencies of agricultural 

methodology in handling forest soil problems. 

This is evident in the much more frequent use of 

foliage analyses rather than soil analyses 

(Youngberg & Davey 1968). Soil extractions require digging a soil pit, while subsamples are 

analyzed using artificial extraction agents. Results show what that particular extracting agent 

can remove from the soil, not necessarily what is 

available and not how much of each ion that is 

used by the plant. 

Soil samples have to be dried, sieved, weighed, 

extracted and brought to volume prior to analysis. 

The process is time consuming and when the data 

are finally available, the analyst knows that the 

results do not directly reflect what the tree with 

its specific mycorrhiza is able to take up. It 

requires about 12 hours to collect and analyze one 

soil sample, not including drying time. The interpretation of forest soil chemical data is still 

part art, part science. 

Because of the problems with using agricultural 

methods on forest soils (Page 1982, Walsh and 

'~yrn~osiurn on "Current Topics In Forest Research" 

'~rofessor of Forest Ecology, School of 

Forestry, University of Montana, Missoula, Montana 

59812 

Abstract.--This paper reviews some of the 

difficulties with existing forest soil and plant 

chemical analytical techniques. The uses, advantages and disadvzntages of the new xylem sap 

technology are discussed, along with results and 

a description of sample selection, extraction 

and xylem sap analysis. Xylem sap is extracted 

from branches or roots using a modified pressure 

chamber. Nutrient distribution frequencies from 

large areas for conifer and shrub species are 

needed as a reference source for routine use of 

the method. The newly developed portable extraction equipment is described, along with results from analysis of sap from wild huckleberry 

(Vaccinium globulare Rydb.) stems, alder, conifers and tropical vegetation. The potential for 

use of tree xylem sap technology to solve specific 

types of problems with insects, diseases, animal 

damage or growth is offered as a challenge to 

expand the method. 

Keywords: Tree extracts, Pinus ponderosa, 

Pseudotsuga menziesii, Vaccinium globulare, 

xylem sap. 

Beaton 1473) and because of the limited financial 

support for Iorest soil chemistry as a distinct 

science, foresters have relied heavily on foliar 

analyses. Foliar samples can be collected from 

conifers at any time of year, however, the proportions of mineral nutrients to organic compounds 

changes over the year, resulting in natural 

changes in the per gram proportions of each 

mineral nutrient. Thus, it is hard to compare 

foliar nutrient concentrations within species 

from spring to fall or from year to year. Annual 

comparisons may be confounded by differences in 

the absolute amount of carbon fixed because of 

variations in sunlight and other climatic factors. 

Foliar samples are not available in winter for 

deciduous species, many of which translocate 

nutrients from the leaf back into the stem before 

abscission occurs. The total time for sampling 

deciduous foliage is a few short months between 

the time the leaves are fully expanded and the onset of translocation prior to abscission. 

In addition, foliage must be collected, cleaned, 

dried, ground, weighed, ashed or digested, taken 

up in acid and brought to volume before chemical 

analyses can be made. Sample collection and 

analysis usual1.y takes t 8 hours per sample, not 

counting drying time. The process is time-consuming and costly. Although Zinke and 

Stangenberger (1979) have established reference 

nutrient-frequency distributions for Pinus 

ponderosa and Pseudotsuga menziesii, these are not 

stratified by possible exposure to pollution or by 

soil types. 

Another approach that has appealed to forest soil 

scientists is extraction of soil water using eith~r 

pressure or tension (Marshall and Holmes 1979). 

Various lysimeters and soil water probes have been 

developed to collect soil water moving under the 

influence of gravity or tension (Hanks and 

Ashcroft 1980). The gravity-fed lysimeter is of 
limrted vaiile in drrer clln,ates when nobile col1 

water is citen ur-iava~lable, Eve7 pressr,re ar~d 

suction de\lces will Fail to produce wscer simples 

in dry sumTers. The pcrous cbps used in soil 

kater probes have a tendency to zccu~ulete phosphate acd other ions, vaX~ng them less \aiaaSie 

o-ve r t 1n;e . 

In spite of these drawbacks, some researchers 

feel that soil water anal::sis is far superia3r to 

analyzing soil eseracrs made with artificial extracting agents. The main drawback is t11s.t 1x0 one 

has established frequency distributions for soil 

water ions that relace in an:J Gsefui way to tree 

growth. 

One other method, 3ylern sap analqsls, had been 

explored by parnologists prirrarily in the ldboratory to study the form of nitrogen transport in 

x> lem sap using suction, 

In 1978, a grobp of scientists at the School of 

Forestry, University of Yontand, began exploring 

the value of xylem sap in conifers as an indlcation of the water stress dnd nutrient stress 

status af trees. 

The idea of syien sap extraction was not ent~relq 

new, Bollard (1953, 1956, 1957) used tension extraction of xqlem sap "om apple trees to stud. 

the forrils and movepent of nitrogen in fruit trees. 

Petchle and Lopushrns~y (1981) collected natural 

root exudstes frov conlters 12 the field and 

analyzed rhese chernlcallq, Scholander and coworkers 11966) bsed the pressure chamber in the 

1960s to evaluate the degree of water stress in 

trees. No one had explored the possibilrty of 

field extraction of xylem sap, using the pressure 

chamber to coilect sap for chemical analysis, 

THE DEVELGPYENT OF XYLEM SAP TECHNOLOGY FOR FOZESTRY 

Once it was established that xylem sap could be 

easily obtained from roots or s~aller branches 

with a large Scholander-type pressure chamber, 

and that the sap had easily measurable ion levels, 

it was essential to develop an understanding of 

the degree and sobrces of natural variation in 

xylem sap chemistr). The sources of variation 

that were examined were changes in ion concentration with differences in: 

extraction pressure 

time of day 

time of year 

tree to tree uithin species, random 

tree to tree within species. paired trees 

betwesn species 

crown aspect 

height into the crown 

tree age 

trees of one species on different soils 

flush versus hardening-off 

12. insect cr disease status: 

a. infected with Endochronartiuri harknesii 

versGs uninf ected 

b. iniesred with Chcristonera occiden~alia 

versos uninfested (same soil) 

c, porcupine-damaged versus unda~aged 

d, root rot-infected versus uninfected 

These preliminary studies made it possible to 

prescribe a standard extraction procedure for 

conifers that can be used for making controlled 

coelparisons of xylem sap chii~istry, 

The res~lts of thousards of sap extractions are 

now available {Stark and Sp~tzner l985a, b). 

These results show that the best way to obtain 

xylem sap from con~fers is to standardize coiIection and analysis procedures. Trees from a 

stand that has grow~l-i or other problems and controi or healthy trees are sanpled with the 

following criteria, tor sampling within a species: 

same cime of day, (one branch from the test 

plot, followed by a brdnch from the control 

plot throughout the day) 

or wrthin ten days in time of each other, 

with similar weather conditions (cloudy 

or rainy days are the best) 

rainy days during the pre-flush period, if 

the problea relates to poor branch growth. 

within the mid-growing season if the 

problern relates to radial growth. 

during winter if xylem sugar storage is of 

concern 

any time of year if the problem is not related to growth and if samples can be 

taken alternately during the day from affected and unaffected individuals. 

trees of + 5 >ears in age 

trees paired hithin a stand or class 

(within affected individuals or within 

unaffected individuals) by similar physical 

appearance, size, crown form, density, 

color) 

samples from the lower one-third of the 

crown. 

on the west aspect if possible, although 

aspect is of minor importance 

within a class, all individuals should 

have the same apparent amount and type of 

disease or insect problem or be totally 

free of such influences depending on the 

objectives of the study. 

Deformed individuals are sampled only when they are 

needed for a specific study. 

Extraction Procedures 

Branch ends or roots 60 cm long are cut and 

stripped of bark for 6 cr at the cut end. The 

wood is cleaned of phioem with acetone, and the 

pressure is increased to allow reading of the 

branch or root water potential. A tight-fitting 

Tygon tubing is placed over the cut end to contain 

the sap as the pressure is increased to 2.0 or 

2.4 megapascais. One milLiLiter of xylem sap is 

removed from the tubing with a syringe and added 
to four mls of 0.12 S nitric acid. This sample 

is then analyzed by inductively coupled plasma 

spectrometer for Al, B, Ca, Co, Cu, Fe, Mg, Mn, k, 

Mo, ?;a, P, Si and Zn. The whole process from 

cutting the branch to data print out takes about 

six to eight minutes. 

A second milliliter is removed from the branch, 

and five microliters are injected into a zitrometer 

for total nitrogen analysis by chemilurninrscence. 

The analysis takes about two minutes. 

During winter, branches store small amounts of 

sugar in the xylem sap behind the bud. It is presumed that this material (for Douglas fir 

(Pseudotsuga menziesii (Mirb.) Franco) and ponderosa pine (Pinus ponderosa Laws.) mostly glucose 

and fructose with some pinetol) =ill support some 

of the rapid new branch growth that occurs in 

spring during flush. If the levels of sugar storage 

are low, there is a possibility that the tree may 

be energy limited at the time of spring flush, 

Root sugars can also be determined through sap 

extraction and tissue analysis. One ml of sap 

extracted in winter is analyzed by the phenolsulfuric acid sugar method (Whistler 1964). 

Since results of the xylem sap research have 

been published (Stark and Spitzner L985a, b), this 

paper will concentrate on newer work and possible 

uses of the method. 

Xylem S~D of Wild Huckleberrv 

Xylem sap extractions have been successfully 

made from shrubs such as wild huckleberries 

(Vaccinium globulare). Shrub sap extractions are 

slower than conifer sap extractions because of the 

smaller wood volume per branch, The sap tends to 

bubble excessively, but collections can still be 

made easily by attaching a vessel to the end of 

the Tygon tubing. 

Xylem sap was extracted from ten or more 

branches of Vaccinium globulare {wild huckleberry) 

growing on habitually high and low production sites 

in western Montana. Samples were collected under 

similar weather conditions within five days' time 

in July during fruiting. The high berry production 

site was significantly higher in Al, B, Fe, Mn 

and Ya in the sapcompared to the low production 

site. The soils from the two sites showed a 

pattern of significant nutrient differences 

(Table 1) for B, Ca, Cu, Mg and Na. Nutrient differences between xylem sap and soil agree for B 

and Na, but not the other nutrients, The reason 

for this is that the roots of this plant take considerable amounts of nutrients from the rotten wood 

of the Oalayer, with less dependence on soil 

nutrients than many other shrub species. Also, 

many of the nutrients are taken up selectively by 

mycorrhizal roots so that soil nutrient availability determined from artificial extracts in 

the laboratory would not necessarily correlate 

directly with the concentrations of nutrients in 

the xylem sap. This is a problem with most forest 

soil chemical data. The concentrations of nutrients in the artificial extracts do not necessarily 

reflect what the plant takes u~, only what is 

available {or uptake usii,~ a specific extracting 

agent, 

Table 1.--Yean and standard deviation of nutrient 

concentrations in xylem sap of -- Vaccinium 

globulare during 3uly from consistantly high 

and LOW productivity sites, and available soil 

nutrients as i:g/g, 

good site sap poor site sap 

liucrient X SD * X S D 

good site soil poor site soil 

SutrLent 5; SC TI S D 

A l l,77 1.4 

IS O.;a L?,L6 

Ca 2819a 418 

C u 1.4a 0,3 

F e 6 2 0.9 

i.lg 203a 24 

Fin 8 3 12 

Na l4a i. 8 

P 18 2.3 

S i 6 4 6 

Z n 6.6 1-6 

K 388 8 

Total N 396 i 1 

a,b- tor soils, two means followed by differenc 

letters are significantly different at p = <.CIS. 

'for sap, ~brse values are significantly higher 

than those for the poor site. 

d~~ - standard deviation. 

The importance of boron to berry production is 

apparent from juice, leaves, xylem sap and soils 

from high berry production areas compared to poor 

producti~n sites, Sodium is hypothesized to be 

important only as a passive ion to influence the 

osmotic potential needed to develop Large fruit 

size through water storage, It is not likely 

that Na is raken up actively so that soil Ka and 

sap Sa should correlate well, 

Xylem sap analysis of wild huckleberry has 

provided evidence of potential control of berry 

productivity by nutrient availability assuming 
that climatic factors are not adverse for a 

particular year. 

Sap extraction from shrubs would be of potential 

value in studying shrub nutrition and in examining 

the influence of fire on the nutrient status of 

shrubs. The value of shrubs to wildlife might 

also be studied using xylem sap technology. An 

example would be the analysis of xylem sap quality 

of the edible branches of shrubs before and after 

fire. 

Xvlem Sav Analvsis for Conifers 

One important aspect of the devel-opment of sap 

technology is to establish what ranges of ions are 

likely to be found in the sap of each major conifer 

species relative to growth rate. This is a 

sizeable job, but some guidelines have already 

been established for Pseudotsuea menziesii L, 

(Douglas-fir), Larix occidentalis (western larch) 

and Pinus ponderosa (ponderosa pine) from good 

and poor growth sites. These data will eventually 

be published and will provide a frame of reference 

against which xylem sap from trees of these species 

in other areas can be compared. Such comparisons 

will almost certainly show significant differences 

in sap ion concentrations by major soil types and 

may also reveal ecotypes. Such broad-based sap 

chemistry data must be assembled and published. 

It will be of potential value in studying air 

pollution. If the crowns are weakened by air 

pollution or the soil ion populations are altered, 

the xylem sap chemistry should reflect these 

changes. 

Xylem sap analyses of subalpine fir (Abies 

lasiocarpa (Hook) Nutt.) seedlings grown under the 

influence of alder (Alnus sinuata (Regel) Rydb.) 

with nitrogen-fixing symbionts and away from alders 

showed significantly more nitrogen in the seedlings 

near alder, as expected. Xylem sap analysis can 

be used to detect changes in plant uptake patterns, 

enrichment from fertilizer or changes in ion 

availability. Sap analyses make it possible to 

detect fertilizer uptake in 70 percent of the 

trials for nitrogen and 60 percent for other ions. 

The timing of sampling after fertilization is 

critical. 

Xylem sap chemistry correlates closely with 

apparent radial growth rates. On sites where the 

soils were different (alkaline, pH 7.5 and acid, 

pH 5.8) but precipitation and temperature were not 

significantly different, Pinus ponderosa and 

Pseudotsuga menziesii both showed significant differences in the concentrations Ca, Mg, Mn, P and 

total N in the xylem sap during summer. These 

nutrients are now being applied as fertilizers to 

determine if statistical significance relates to 

biological significance -- i.e., radial growth. 

Xylem Sap Analysis of Roots 

Roots of trees may also be extracted for xylem 

sap but not as easily as branches. For shallowrooted species such as lodgepole pine (Pinus 

contorta Dougl.) it is relatively easy to locate 

a secondary root near the base of a tree and pull 

the root loose with gentle excavation. This 

method worked well with shallow-rooted tropical 

trees as well. Roots are extracted in the same 

manner as branches. A comparison between root 

nutrient concentrations and nutrient concentrations in the lowest live branch provides an estimate of how much nutrient is being used by the 

bole in radial growth. 

Xylem Sap Analysis Of Tropical Species 

Routine xylem sap extractions are made with 

equipment mounted on the tailgate of a pickup 

truck. This system works well wherever there are 

roads. In July 1986, the equipment was made more 

portable for use away from roads. The pressure 

chamber was mounted on an aluminum pack frame 

with short feet to allow it to stand three feet 

high for easier use from the ground. It is difficult to haul a large air tank over uneven 

trails, so the air system was modified to use a 

SCUBA airtank for the air supply. This required 

adapting a SCUBA regulator that connects to the 

tank to a two-stage air regulator that will control delivery pressure to the chamber by tapping 

into the high pressure port of the SCUBA regulator. 

When mounted, the system weighs about 24 Kg, plus 

the weight of the air tank. The SCUBA air tank 

weighs about the same as the pressure chamber and 

can be carried in a SCUBA tank harness or a 

standard backpack. A SCUBA tank will permit about 

20-24 extractions at low pressure (150 psi). The 

front pouch of the backpack is useful for storing 

the syringe, vials, knife, tubing and other 

accessories needed for extraction. 

The portable extraction system was used successfully in Panama at the Smithsonian Tropical Research Institute's Barro Colorado Island Preserve. 

Branches were extracted from Hybanthus prunifolius, 

Psychotria horizontalis and Psychotria furcata 

(all understory plants) from plots receiving supplemental irrigation during the dry season and 

others that were not receiving irrigation. The 

study is being conducted by Dr. S. Joseph Wright 

of the Smithsonian Institute and the author. The 

objective of the study is to develop an understanding of the normal functioning of this tropical 

ecosystem by removing one stress--dry-season water 

deficits--and comparing the nutrient status of the 

soils and vegetation with and without dry-season 

water stress. Results are not yet available, but 

there are some interesting trends in nutrient uptake that will be reported at a later date. 

SUMMARY 

In summary, there are many possible new and 

potentially valuable uses of this technique, 

especially now that the extraction system is portable. Problems of tree growth, disease or insect damage, animal damage and many other possible 

uses of the method have been tentatively explored 

by the author, but there are many uses yet to be 

discovered for this new analytical tool, all of 

which could help to advance the field of forest 

science. 
LITERATURE CITED 

Bollard, E.G., The use of trachael sap in the 

study of apple tree nutrition. J, Expt. Botany. 

1953. 4 : 363-368. 

Bollard, E.G. The nitrogenous constituents of 

xylem sap. Am. Soc. Plant Phys., Proceedings. 

1956. 31:9. 

Bollard, E.G. Composition of the nitrogen 

fraction of apple trachael sap. Austr. J. Biol. 

Sci. 1957. 10: 279-287. 

Hanks, R.J. and G.L. Ashcraft. Applied Soil 

Physics. Springer-Verlog. New York. 1980, 

159 p. 

Ketchie, D.O., and W. Lopushinsky. Composition 

of root pressure exudate from conifers. USDA 

Forest Service, Pacific NW For. and Range Expt. 

Stn., Res. Note PNW-395. 1981. 

Marshall, T.J., and J.W. Holmes. Soil Physics. 

Cambridge University Press, New York. 1979. 

345 p. 

Page, A.L. Ed. Methods of Soil Analysis. Part 2. 

Agronomy No. 9 (Part Z), Madison, Wisconson. 

1982. 1159 p. 

Scholander, P.F., E.D. Broadstreet, T. Hammel, 

and E.A. Hemingsen. Sap concentration in 

halophytes and some other plants. Plant Phys. 

1966. 41:529-532. 

Stark, K., and C. Spitzner. The technology of 

xylem sap analysis for studying trees. I. 

Pseudotsuga menziesii. 'J. Can. For. Res. 1985a. 

5~429-437. 

Stark, N., and C. Spitzner. Xylem sap analysis 

for determining the nutrient status and growth 

of Pinus ponderosa. J. Can. For. Res. i985b. 

15:783-790. 

Walsh, L.M., and James D. Beaton. Soil Testing 

and Plant Analysis. Soil Science Society of 

America, Inc. Madison, Wisc. 1973. 491 p. 

Whistler, R.L. Ed. Methods in Carbohydrate 

Chemistry. Academic Press: New York. Hassid, 

W.Z. and Neufeld. 1964. p. 33. 

Youngberg, C.T., and C.B. Davey. Tree Growth and 

Forest Soils. Corvallis, Oregon State Univ. 

Press. 1968. 527 p. 

Zinke, P.J., and A.G. Stangenberger. Ponderosa 

pine and Douglas-fir foliage analyses arrayed in 

probability distribution. In: Forest Fertilization Conf., Edited by S.P. Gessel, R.M. Kenady, 

and W.A. Atkinson. Univ. of Washington, Institute of Forest Resource. Contrib. No. 40. 

1979. p. 221-225. 
3ctomycarrhizbe (M) , t?:? sp'uiotic root-fu_~t;as 

azsoeiatiozs 05 xany tree s?ecies ;ndIgencxz to 

tenperate forests, a,re ck~racterized by cwolLen 

rook tips of the host s9e:les. I:,mgal hyphae 

grow as a xantle covericg "ve root with the expa:;ded hypna!. zetwnrk is t-e ccil s ig~iificant iy 

lncreasi~g Lie absor~tive sur%ce of %he hosz 

roc$ (3'3-c~er1, 1973; Skinr~er ar,d hover, igyi). ir, 

t,his way, M enhacce iuk aptake of essertial e1.exent c sach as p'r:ospii~r~~.- ,s (:'owell, 1982). ?he 

irn~ortanc eof ec tonyeorrklzal root:: ?:as been 

denonstrated in nlztrtent poor scils (sowen, 1973; 

Harley, 1969). 

IV-~qero;~ paraaeters influence cctoaycorrhiznl 

forxation and f-~nctior. Sol; nutrient factors , . promoting ecto~ycorrhizal fcraat~on inclade 

xoderate to low levels of P and N (ldarx, ct al., 

1977; Foweil, ~982j. Low ? levelz ixcrease phosphatase activity ard F wtake (~lexander and 

HarQ, 1981; Rartiett ard lie;.rLs, 1973; Xghtor, 

1983). In acid soils essential nutriects are 

generally io~, a si:i~at i on ?avori::g ectoxycorrhizai f ormat ion 2nd fx~ction , but !.cavy metal 

avziiability is er:ha.ncea (3uciixian an6 Erady, 

1969). The toxicity cf heavy ~~etals on ec;crnycorrhizzl fungi (Thompson and "edve, 19843, 

root gro~hr! and biological I"uxi3tion (3'37, e% a;. , 1978) , have been demonstrated. Oi~r field szrfigles 

have indicated heavy rzetal loadizgs In oak M frorr 

acid-xor but zot froz ze~tral-null forests 

(Xa,;urdar, et ill., 1986); -de ba;re Frevicl;sly 

shcwr? the ectomyccrriiizai freque~cies (147's) of 

oaks in the acid-mor to be zonsiderably lower 

thec those in ~eutral-xull fcres5s (Xixeo et sl., 

1984 j . go%h divers it;r of r~ycorr?~L~a; fungi 

and resultant ectoxycnrrbizai morphclog~ differ In 

, - "?resented at tke Synposimi on Cmrezt &opics irForest Research, A Nat Ional S~?~psirn, Novenber . - 4-6, 1986. Saines~i-il-e , Florida. 

2~epartmect of Iiology, Lafayette Csllege, 

Eastor-, PA 16042. 

3~eFartmen~ ofMetallurgical Zngheering , iafayette College, Easton, 3 118042. 

>[os;ract. --Zctorn;rcoryIc_iz& ronzs sf two forestgroTE zak specles , 2l;erc-as alba a~d g. rubra, . - -- e.;r,;z:r:ec s %~~if tcarztly ao-r;.e cslcia3 in the neu- . - tra1 "~2;s-a~ll ~h;=~? In t?ie 3,:id:c h-&%;r-s-ynor salis. 

?:;oa~hcr+zs ~~ntezt T,.~as L'e~~rs~d ; tkat is, 3ak 

eC--wyeorr~~zae -81.. ,--".- b~b-LcL--L :,Ted - aA5~--. : --; *: -~z;;tLy h5gFAer -, - - -- .- z:lgscytorus _e~.~e-- 52 nor r-t'er t?ian ~~3~1 ~=:,z. ,- ,rese - rcc-~it;, ci;~~l~ei ;15-,c x-ray n~croana~j;~ is 

.- - r.--T;ected a\-al_:lc,i. ~alc;-&y zxii skas-c.&rus - A 

zo-;enhf erac?: sr?LI :L-rpe, 2-6 cl2ser exaxit- ,,.-, 4- -,,A : ,,- r.n-- ,I ,eyl;pr? <yi) :-t.;y<z:cry ycle 55 ectfi3. -, 

- yycoylr:: i'cr u:~.~sD~~-c;;~ ~1;: , 

c.3- d,i,,,a c-~:F>~ 7 e.2 ~r, add l- -. ; ignsl i-essul~:jry of pc$oxiycc:-rri:zse (24) f3r 

-. . . - 7 

. , li-1. 'l,Lc :-27; 1 r_ :::el 1%;~- :;0 115 ~ppfzr~d 

i;~ be ?~c--lded +?vi;:~ 2i;, 

xcr ayld niLL oak forests ( :lcr;ubllsheix, MI:ieo, 

et al.). AcLB en;-;ror,nefitn r:sy fsvor neither 

ectonjrcorrhizal "orma~ior, nor i'l~rc<io:;, bat xany 

L~-,terzcting "ctoi.~ are i:lvo:ved ix 3:e~~ prr,cesstr. 

;'arj.o:j:: r,lqyrjczL f'actcr.2 er:c,3-2yat-;e ectorr.ycorrhtzsl fcrniatiori a,yl~i i'?~qi3ti~iri such as xoderate 

soil aist;re, aeratio:; ax2 ternperatiires (Fr;wel1, 

1982). Zoot 2eszity ;;Lor,e lias 5eec sh:>'gn to 

icfl;ie~,ze sol,~te s;?t,;~:i.~ from (~nlc?;ri?, 

et all., 1972) ; St. John ~d Cole~a:~ (1983) 

r,oirt,i,l-d 3;i t.*:e Inl~cir",::ce .~f'a,~~ailabi;le soil 

vol~~?!e and com;r;r:lty sLr.7~clui.e In the o7;erall 

assessrgent of the biologiczl significance of M. 

Ectomycorrrizae, although Influenced by the 

many varj ables of natural eqvironrientc , beriefit 

the host ~lants iq several ways other %ban the 

lncrease cf es sent la2 elexev,t u;?:ake. ;or example, 

t:ie hornlonci balance of Y o?fl'setc the aging of' 

those root 5i~s (Meyer, 1974); alco tne protection 

agair,;t certain pattoge~~; 'serlkiaxce3 by %he proci1;c+,io-" gf ant inicrobial co~pol~r~c?s an3the forma- Cf L:GY~ of a ~5ructilred ri,iz?;phere contalcirg other 

becef lcial xicrobes (Varx, 1973). Is a d d l t i o n , 

T'ogel (1980) and oti-erc have pointed out the 

ixportance of M in rirtrient cycling processes il 

natural environments. ;c tlzn, ectoxycorrblzal 

f7zngi are dependent upoc their hosts for both 

carbohydrates (~:ork~an, 1970) and other suostances 

s~ck as B-vitaairs ; pnot~synt~esis , then, has been 

correlated wit n nycorrhi zal develop~en~ (3; orknan, 

;?TO; Marx et al., 1977), wlth decreased. photosynthesis ca~silg decreased :47. 

T%e pispose cftt"' ,,s st d3jr was to compare i,h? P 

a~d Ca c3ntent of o2k ec:cn;~corrkizal mantles 

frc~ two differert forezt soils with the content 

of those soils and t3 corsider the irfluence of 

M on the incorporation cC P and :a into both the 

nantle and host fine root tissues. Thls attempt 

to acderstand natsl-i processes seems appropriate 

corsidering t3e irrportance of oaks in many forest 

comn7~~ities andthe general lack of thLs klnd of 

i~format ion for these species. 
- ~ . - derAyLrL4r~<; -: Td:.e 2sy::lg a:, :$3L, 922 rzc;;s>:: . - sey~~;~s ;I~-S.F_. cc __e~:e-; ::cr,";?:l-,. (>t~~--3ep,err,be-) ir ,p ucJ,dA- ,. c > y-iii-i -, - &:.-: WT>V '-9L*Ll<.+ - ,-r*-w-f- TCS+* -*:r7 

..li,_ _ \~d* L%-I.+; ":-- ..'-"rLL.'a 3:- . '- :, r. -2 -,. l J-;T, et el, ,_979). S21? acd tizsxes -,-ere i' ... - La~en ?~,--nc -A d-LL -,- ,<A - ,--A'A 1- - 77 =:e fc; Tar e;;-o;:es c" &-,perYrlt-;J S <,.-> - 4.;"' =rtes (25 to 7-6 <.Q-..- :'.;2.-prS -. -I--2 ---lL-.'.L L..- ta:a- 

%-is "V. 

. . - ,.--- 'in-. * 7 11 .,At; ,,L 51 bz-ei;;t .I~~GII) . uc-..r ..rLt-.L refers ta 

~'-,ry-;pd s,_>L 1; -,qi",l. a h-&~~:l~-j-j~j: layer co-zistlr,~ 

c~ e;r,-c; . - =lr,c;:-eL . ail13 g3irgeulic r::aterlal t?.2", k?e:leL 

- #,:,l-,_l*" -7 + , ,. a:; &br;i3; chzrAg-;e in sol'; Lsi-L3rscteyistlcs. 

P.;-J~= Teetie --,>* r #.,,,; nr;d 1.1 weye Iccated i~ ";Le .A? -. rlcv--3r, -&-r;~c:; -.. (23 centiyrLeter~l azfi i-cjLs,- 

~l-,~e?-- ~t~~e-fyce. yko xrm, "xor" rt)ye_r~ c-3 -Y ., ,~ . fS3reste6 so; is wl"; a an:i;rlpcr,, ;uy:nc?raorr",ed 

h- .r,. 

.-. LuLL~:5 :-:?.yet7 0:' orgzr-ic ~!e~e_r;z,~ ::iz; Is ~YTc::: . . J, 7. Ifas?; of the Ceeuer r.)ci,s ~. 3s-j " TJCS Ls~.a-,e~ ;c ;::e s:;a;lo-~ (7 ,e:li,i,e?ders) ,. - 02 horlzor, ~1l-c:: was nfter: story. St~uy erez~s 

bier... -A~ctk-i;i L~ 25 rr;<l- rs,<us or eec? sthey znd 

- wev.e - ,-'.px-.~-- 20 excli;de siopec gr ,zis~,l;rbed :;cil:;. -A -.-'uL> -A& 

.7 c~--.;ao;itc so:, s~~~pies fro3 euc? ?cre::-k,y?c 

w~1-o ancj,-ly-& ~ea:;o-ally Sy tke Sail 3:la 5::jircrn;,e:ltal- Che~istyy r,a-~oratcries C i_';:e :'enr:sylvar,ls . - Sta", eniv2rs ;ty. S.i,a:;j;~yd n;et:locs us fcl;-;il il; 

Zlack (1965) were used tc ob;aln plhnt-available 

levels of elernenzs . L'otessi-AT mil calcl-~nn values 

were ob",air~ed fron arL~:o~1~~"i zcel;aC,e e)itr~ac~;5ors, 

while ~?~ospi:or?;s valses were cbtalned fro-. ar~~o- . . niu~!: f1;jor;ac.i e)ii;rac-,io-s. rr,ean val-~es of . - plant-avz~llable e;eme::", i~:: the qper so: - korlzcn 

cP each forest (~a51e I) wex-e calc2lated f'rox 5 

sarngle sets taken over a 3-year perioi (1984- 

1986). Each saaple set -4as cornprlsed cf I0 seil 

cores . 

200% Analyses 

Representati~~e active ec?,omycorrhizal roots 

., .- , (swollen and light-co~ored) ckcsen from tne solij 

root szmples were fixed in 7iA (CCTC~I~T, 5C percent ethyl Zlcghci and glacial acetlc acid; 

5: 9C : 5 1. Soil-free M chosec al; randox f,2r elemental analysis were cross-sectionec -sing a 

crycstat, dcky3ra;ed in a- elnanol series ayld 

critically polat Cried. The rsots were :hecarbcc coa$ed a1:d ?laced orL carbon ~icrosco~y 

st?jTcs. l;?wen;y-f lve rooi;s frorr, each l.oca";cr ~r,d 

for each sgecles were anal;rzec for ele~~ental 

contezt using a Trincetor Ja~~ma-Tech Syste. L;Z 

energy-dlspersi-4-e s~ectrorneter 'EDS) attacked to 

s scanning eieczron xicrcsce3e (~ig-ze 1). C-zing 

aL a,nalysls, an electron beazn foczs-2 or ;he . . -. , sample pradxcej an x-raj exlsslas ?attern wri;c!: 

the 22s cetected. The x-ray courts (or intenzit2-1 

were displayed as a f:;r~ction cf x-ray energy. ill ise specsral peaks csrres~cedeC to constituen; 

eLements within the semp;e; c=ntinra x-rays 

(background) were roi;=ine;y subtracted frc~ the 

characteristic x-rays (Figures 2 and 3). 'Tith 

this technique exact elenental ccnce~trstlons 

cannot be directly obtained, b7at spectr:m peak 

areas (or x-rey intensltles) can be corriuared 

betweex diflerer_;; sa:qles to determine wkickL -. sanpie cas xiore sf n partiealar elemest Ln guesC o r on (I>.-:-.-.. , ,,_, etor c~~~~a.-T~‘ecn, 1981; . ?or example, 

the d--- TPPC-~P ccrcertya~lon of czlci3&y ;ri:hia 

t?ss-je carrLct be deterai~ed, 73~2t $he ratio of Ca 

x-ralr izC,ecs:ty,!~ x-ra;- l:lter,~i",- ?ram izne speci- pcir .,,,,_ pr-n -a,,.. be ~_.ozcareii to ;hat s? anotker. 3a%i~ 

'.. lie Q rirr~~r: ree c-o irkere-t vzriat i3n that 

,7n-,--F- --iLli a ;if-rr: ssn~le ;o s~xale such as differences 

In s-;-<ace ro~;ghr_ess (a-d cell ijrientatic;;), and 

Ir; -no-, size, s,<n cf ",e filmen;; or r7&r tixc. 

"22 tine of 153 secc1:2s, spct size -~hLck prod-xed 

203 co-jnt; ner secocd 2nd workicg dis:arce of 23 

rnilll-eters xere routinely xed (~oldstelr , eh.2. , ;gal. ) . I- order to normelize tke apec- 

.* L, al Lnfcr~z:io- Tor coxparative p-2goses, 

potassi-m; was ckosen as the ratio denorninetor 

si:~ce cl-,e~~Lcal ar,aY.yses Lrdtcated that potassi-ml 

was si~;ilarl;r xiallajle in muI; a.rd mor soils 

('i'a'cle I) znd sizce potassilm appeared to be , . pl-ese~'~ 1:: + ,re ' mid-rarce of cozcts cn eac5 spec- 

. !xtxai cozcentratic~s of K, Ca acd 3 for 

bulk fine rock tiss-~es were determined by the 

!?ora{;e Ie;tlr_g Laboratary of The Pennsylvania 

Stete Ynlverslty able 2) asing we-asking procedures co:lg;ed wit:? absorgtion flare scectro- ,- 1- kAAotoxetry methodc (Srr;tcll:"le azd Saker, 1978) . 

?he 3s x-rsy xlcroarialyses were =;erfor~ed 

arc~zd ;:ye outer cortex of each sa~ple in the 

-c -, ,- ,. - ~,los of t?-e ~*r7,ic0rr~:zai nantle. Relative x-raj 

I~~tensities of eLernects wizhin a given root 

smpl e were basically siziilar for vario-~s altercate Locatiocs 03 the ceripkeral mantle. 

Eastern ?ezns2-lvanla is geologically diverse; C1 

LL~ roils of the Lehigh Valley region, where 

forest-1x1: samples were collected, were iierived 

nalrly fro^ ~eutrallzing carbonates cf limestone 

and dolomite (Soil Szrvey, 19741, and resulted 

in ce~tral soils (p~ 6.5-7.1, AH horizon) with 

low Levels oT keavy metals and 12 percent organic 

matter (~izeo, et al. , 1984;. Four x~ll fcrests 

were sa~cled; in each fcrest , oaks (~~ercus alba 

and -- 3. rzbra) predominated. The understories 

vere coviprised of -- Scrnus florida, Vibernm spp., 

Fhus radicans ad various herbs. The overall 

root decstties per wit vol-me of scil were low. 

1r. cor~Lrast, the ?ocoxo soils, where forest-mor 

sazples were collected, are uqderlain trith sands:cae, shales and conglomerates and possess less 

b-dffering capacity. The rescltant nor so5ls of 

the 52 korizc- were acid (p~ 3.8-4.7) with high 

levels of available heavi metals and 41-51 percent orgacic material (Mi~eo et al., 1984). Two 

nor forests were sampled; caks (~ueraus rubra, 

- " - - ,. 2rixlus, 2. a~ca ard - 2, vell;tica) predominated 

with -- Acer rubrm as a cormon associate. The 

-&riderstories were coxprised of Ba.r;a,melis V' r"' 

,- lniana, PhodadenL~on spp. , TJacci~im s2p. , Gayl-dssacia spp. , Ga~ltheria procu?ibens and 

<<verse mosses. The overall root densities per 

-.,- u_iLb ;+ vo17miz of soil were high. 

P_lthougtL the geolcgj, soils and co~mxmity 

structure ia each forest type differed as stated 
above, the forests appeared to be similar in soil 

aoisture, aeration and temperature. Also, all 

saxpled oaks occupied the overstory and received 

direct sulight on a sizable portioK of the 

carcpy. 

Calcium and pkospkorus concenxrations differed 

is eac5 soil type. Calciari levels were especially high in the mill solis (mean, 2,856 ppm) 

but lower in the mcr soils (xean, 500 ppm); 

xhese meac va17~es were significantly different 

from each otker (iL?VOVA p 9.01 . Phosphor-as 

levels were somewhat reverse&, that is, with 

lcw-normal Levels (niean, 29 ppm; in the mor scil 

but with low concentrations (mean, 10 p;sm) in 

the m~ll soil (A_TO~~A p 0.05) (Table I). On the 

other hand, potasslum levels of both soils (245 

ppm mull; 230 ppm mor) were similar. ?he data 

in ?aisle 1 represent the plant-available 

nutrients of the upper soil horlzon, as most 

of the M and fine roots were found in this 

horizon . 

Table 1. Elemental Content (pprn) of Mor and Mull soiliw2 

P K Ca 

Mull (neutral) 10- 2 45 2.856 * 

Mar (acid) 29 230 500 

'values, as ppm, represent the means of 5 sample sets taken 

ever a 3-year period. Each sample set was comprtsed of 10 

soil cores. Values are given for the A hortzon only. 

2~otl analyses were performed by the Sot1 and Environmental 

Testtng Laboratories of The Pennsylvania State Universtty; 

plant available Concentrations were determined according 

to standard methods (Black. 1965). 

* 

null, stgnif icantly df fferent from rnor (pcO.0 1. ANOVA) 

M 

Mull, stgniflcantly different from rnor (p<0.05, ANOVA) 

The calcium and phosphorus content of the 

mycorrhizal mantles generally reflected the 

availability of essential nutrients in these 

soils. X-ray microanalysis procedures, which 

displayed the nascent levels of elements within 

this small tissue area, indicated that calcium 

levels were high for both oak species in the 

humus-mull (black bars) but low in the humus-mor 

(hatched bars) as shown in Figure 1. These 

calcium (c~/K) values of mull M were significantly higher than calcium (c~/K) values of mor 

M (ANOVA p 0.~5). Phosphorus levels, on the 

other hand, were reversed; that is, low in the 

humus-m?..iLl (black bars) but high in the humusmor (hatched bars) and also significantly differed from each other (AEoVA p 0.05). 

1 evels of CnllllllIl and Ph~gm 

rlm-ive to pot*- Leveb 

rngm-w 

Figure 1. X-ray microanalysis data tndtcated that both red and whlte oak 

mycorrhtzae contained higher calclum levels in mull (neutral) 

than In rnor (actd) solls. The reverse relattonshlp occurred for 

phosphorus; lower P levels were found In the mycorrhlzae of 

mull soti than in acld solls. * 

Mull, stgntficantly dlfferent from rnor (p<0.05. ANOVA) 

Representative x-ray microanalysis spectra 

(~igures 2 and 3) exemplify the results of 

Tigure I, namepj, high calcium levels in the 

mycorrhizal mantles of red oak from the humusmull soil (~i~ure 2) with moderate potassium and 

low phosphorus levels as well as low heavy metal 

levels. Figure 3 indicates the moderate calcium 

and potassium levels, but also the high phosphorus levels, in red oak mycorrhizal mantles 

from humus-mor soil. Enhanced heavy metal content is also visible on this spectrum. Spectra 

of white oak M were similar to those of red oak 

in each respective soil type. 

A comparison of soil contents (Table 1) with 

relative ectomycorrhizal mantle contents 

(~igure 1) suggests a regulatory role for M with 

respect to cation inclusion especially in high 

Ca soils. The mull soil which was higher in [Ca] 

than [K] by one order of magnitude, showed only 

slightly more Ca included in M than K. This 

suggests differential incorporation of Ca and K 

into M; either K is excessively favored or Ca is 

excluded from the M. Calcium exclusion is consistent with the intricate roles of Ca in plant 

development (Hepler and Wayne, 1985). 

A comparison of [P] in soil with that of [K] 

 able 1) also demonstrates one order of magnitude difference between the availability of these 

two elements, but the inclusion of similar amoucts 

of both elements in the 14 from mor soils (~igure 

1) emphasizes the accumulation of P by M when [PI 

in the soil is low. The enhanced P content of 

the mycorrhizal mantles, over that in the surrounding soils, is consistent with the data of 

several other investigators for species other 

than oak (.Alexander and Hardy, 1981; Bartlett 

and Lewis, 1973; Dighton, 1983; and Skinner and 

Bowen, 1974). Our data indicate that oak M also 

concentrate phosphorus. 
RED OAK flYCORRHlZAL WLE 

Table 2. Elemental Content (pct) of Bulk Fine Root ~issu:'*'~ 

Flg 2. X-ray mtcroanalysis spectrum (corrected for background 

emission) of Red oak mycorrhlza in humus-mull soil. 

August 1985 

RED OAK fWCORRHfZAL CUNilE 

Fig 3. X-ray mlcroanalysts spectrum (corrected for background 

emission) of Red oak mycorrhlza tn humus-mor soll, 

August 1985 

The differential Fcontent of mor and mull oak 

M, as indicated by x-ray microanalysis, however, 

does not reflect the overall P content of fine 

root tissue able 2). The P content of both 

mor and mull b5 provide the same general P content 

to the host tissue (0.10-0.13 percent). This 

rather even distribution of P to fine root tissues implies a fwther regulatory role of 14 with 

respect to the host plant; the actual mechanism 

of the movement of P into host remains inconclusive (elarkson, 1985). These data for the tissue 

levels of P correspond to those reported by 

others for oak (~ogel, l980), for tree species 

other than oak (Chu-Chou, 1978) and plant tissues 

generally (Sutcliffe and Baker, 1978). 

- 

nu11 O.1° 0.9 1 0.83 

Red Oak (0.08-0.1 1) (0.66- 1.16) (0.55- 1.27) 

0.13 0.6 1 0.50 

'Or (0.12-0.14) (0.49-0.68) (0 3 1-0.64) 

Mutt 0.12 1 .OO 1.18 

White Oak (0.1 1-0.13) (0.79- 1.33) (0.88- 1.57) 

0.13 0.55 0.56 

-- 'Or (0.1 1-0.16) (0.49-0.65) (0.25-0.80) 

These data represent the mean value of several trees of each 

species in each forest location. 

L~he data for two successive summers were comblned (1985, 

1986) wlth the range of percentage values in parentheses. 

3~lne roots are 1.5 mm or less In diameter. (Mycorrhlzae made 

up only a small amount of the bulk llne root samples. 

The calcium and potassiiun content of bulk fine 

roots (Table 2) from mull-forests appeared to be 

similar in botk red oak (Ca, 0.83 percent; K, 

0.91 percent) and white oak (Ca, 1.15 percent ; 

K, 1.00 percent) but were present at uniformly 

lower levels in the aor-forest roots (~a, 0.50 

and 0.56 percent; K, 0.61 and 0.55 percent). 

The high Ca levels of tke mull mycorrhizal 

mantles, as indicated by x-ray microanalyses, 

were not found in the fine root tissue. Although 

the fine roots of the mull forest contained 

higher Ca levels than those of the mor forest, 

the proportion of C~/K was lower than expected 

in the mull and higher than expected in the rnor. 

These results suggest other differential or 

regulatory roles for the ~ycorrhizal mantle at 

the host-tissue interface. 

The calcium levels found in fine root tissues 

from the mull forests (0.8-1.1 percent) were 

consistent with those reported for plant tissues 

generally (~pstein, 1972; Sutcliffe and Baker, 

1978); however, the tissue-calcium levels found 

in the fine roots from mor forests were at the 

low end of the range (0.5 percent) and approached 

the marginal concentration supporting mitosis 

(~epler and Wayne, 1985). The lower values reported for mor roots were less than those reported for river birch in acid soils with similar 

available f Ca++] (~artuska and Ungar, 1980) but 

were closer to those reported for Quercus robur 

as presented in the review by Fogel (1980). in 

an evaluation of Cac+ in plant development, 

Sepler and Wayne (1985) have pointed out the 

paradox of intracelluilar Ca++ function at submicromolar concentrations but an apparent requirement for Ca++ at the millirnolar level o-~erall. 

Although xany factors other than M influence 

plant productivity (st. John and Coleman, 1983 ) , the soil-root interface provides a significant 

portion of the prerequisites for potential prcductivity and needs to be considered as part of 

the total picture. A regulatory role of M has 

been suggested by these data for Ca as well as 

those proven for P; however, in the case of Ca, 

exclusion is suggested when soils contain high 
Ca levels. Znder these conditions Ca exclusion 

is consistent with the role of Ca in plant 

development. 

Ve wish to thank The F'ennsylvania Power and 

Light Company of ALLlentown, PA_ for a suppcr5lcg 

grant to carry out this study. 'tie are also 

appreciative of Professors L.T. Stablefcrd, 3. 

XcCreary and C. Holliday fcr review and comment; 

and we are gratefd for the kelp of Kr. R. Ho2.5, 

Mrs. J. Cljilner and Mr. L.P. Auerbach wizk nzanuscript preparation and technical assistance. 

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from a serpentine site. Soil Biology and 

Biochemistry l3:301-305; l98l. 

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1977. 390 pp. 

Baldwin, J.P.; Tinker, P.B.; 1@e, P.H. Uptake of 

nutrients by multiple root systems from soil. 

11. The theoretical effects of rooting 6ensity 

and pattern on uptake of nutrient Cron soil. 

Plant Soil 36:693-708; 1972. 

Bartlett , E.M. ; Lewis, D.H. S-uface phosphatase 

activity of mycorrhizal roots of beech, Soil 

Siology and Biochemistry 5:249-257; 2.973. 

Bartuska, A.M.; Ungar, I.A. Elemental concentrations in plant tissues as influenced by low pH 

soils. Plant Soil 55:157-161; 1980. 

Black, C., ed. Agronomy No. 9. Methods of Scil 

Analysis, Part 2, Chemical and rnicrobiologicai 

properties. Madison, Wisconsin: American 

Society of Agronomy, Inc; 1965. 1572 pp. 

Bjorkman, Erik. Forest tree mycorrhiza - the 

conditions for its formation and significance 

for tree growth afforestation. Plant and Soil 

32 : 589-610 ; 1970. 

Bowen, 6.0. Mineral nutrition of ectomycorrhizae. 

In: Marx, G.C.; Kozlowski, T.T., eds. Ectomycorrhizae - their Ecology and Physiology. 

New York: Academic Press; 1973:251-205. 

Suckman, H.O. ; Brady, K.C. The nature and 

properties of soils. 7th ed. Kew York: Macmillan ~o.; 1969. 653 pp. 

Ghu-Chou, U. Effects of root residues on growth 

of Pinus radiata seedlings and a mycorrhizal 

fungus. Annals of Applied Bioloa- 90 : 401-416 ; 

1918. 

Clarkso~, D.T. Factors affecting mineral nutriect 

a: quislt lor plact s . !x~uel Zevie-d of ?lant 

~hysio~og--- 35:"~-115; 1985. 

Dighton, J. Phosphatase prodxctlon of mycorrhizal fang%. Tiant and Soil 7;:455-462; 1983. 

Zpsteir , Z. Mineral ri-r;tri%Lcn of gle~ts, - --. -~rincipies ecd pers~ectlves, Wev York: J, dliey 

an(2 Sons ; 1972. 41t pp. 

- * Pogei , Zobert . Mycorrnlzae and cutriest cgzlicg 

in natural forest ecosys"ems. Piew P'n-y-tolob~ 86: 

199-212; 19e~. 

Fcy, C.Z. ; Chancy, R. I. ; X'rii%e, M. C. The physiclog; of xetal toxicity in plants. Ann-~al Peviesr 

of 21ant ~hysio~3gy 29 : 511-566; 1978. 

Soldstein, J.I.; Newberry, D.E.; Eichiin, F. [and 

others]. Scannlng electran microscopy and x-ray 

xicroanalysis. Xen York: Plenir,-ri. Press; 1981, 

673 pp. 

Harley, J.L. The biology of xyccrrhizae. 2nd ed. 

London: Leonard Hill; 1969. 334 pp. 

Harvey, A.E. ; Larsen, M. J, ; J-mgensen, M.F. 

Comparative distribution of ecsc~ycorrhizae i~ 

soils of three western Montana forest habitat 

ti~es. Forest Science 24 : 3512-358 ; 1979. 

Hepler , P .K. ; Wayce , H. 0. Calc i7m 2cd plant 

develop~ent. Annual Eeview of Plant Pk;ysi2logy 

36:397-439; 1985. 

MaJ7mdar, S.E. ; Wasseman, J.L. ; Mineo, L. C. 

[and others?. Scanning electron microscopy and 

x-ray microanalysis of ectornycorrhizal oak 

roots froa acid and neutral soils. Proceedings 

of the 11th congress on Slectron P4icroscopy, 

Kyoto, Japan; 1986 (Vol. h):3299-3300. 

Marx, D.3. Mycorrhizae and feeder roo% diseases, 

in: Yarks, C.C.; Kozlowski, T.T., eds. Ectomycorrhizae : their ecology and physiologj. 

New York: Academic Press; 1973:351-382. 

Marx, D.H. ; Hatch, A.B, ; Mendicino, J,F. High 

soil fertility decreases sucrose content and 

susceptibility of loblcll:f pice roots to eetomycorrhizal. in%ction by PisoiLth~s tiactorius, 

Canadian Journal of Botany 55:1569-1-574; 1377. 

%eyer, Franz B. Pkysiclogy of xycorrhizae. 

Annual Revie-tx of Plant P'iysiology 25 : 567-586; 

1974. 

7,. :fizneo, L. , Maj~~dar, S .K. ; ?all, G, [and otkers / , 

Preliminary study of the ectomycorrhizal 

distr5bution of white oaks in eastern Pennsylvania forests. Proceedings of the Pennsy17rania 

Acade~y of Science 5E : 92-96 ; 1.984, 

Powell, Conway. i&jcorrhi za . In : Barns , R . ; 

Slater, J.E., eds. Experimental Microbial 

Ecology. kst~ri : Blackwell Scient if Lc Publications; 1982:4L7-471. 
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Princeton, NJ 08540; 1981. R-48 pp. 

Skinner, M.F.; Eowen, G.9. The uptake and translocation of phospkate by mycelial strands of 

pine mycorrhizas. Soil Biology and Biochenistry 

6 : 57-61 ; 197s. 

Soil Survey 0f Sorthaqpton Cxaty, Pennsylvania 

(~ov'z ~ocment). US3A Soil Conservation 

Service and Pennsylvania State University; 

1974 : l03-lob an6 116-117. 

St. John, T.V.; Colexan, D.C. The role of mycorrhizae in plant ecology. CanadTan Journal of 

Botany 6i:1905-1014; 1983. 

Sutcliffe , J. ?. ; 3aker , D .A. Slants and Mineral 

Salts. London: Arnold Pub. LLd; 1978. 60 pp. 

Thompson, G. ; Medve , R. ZEf ects of aiuminum and 

macganese on the gro-x%h of ectomycorrhizal 

fmgi. Applied and Environmental Microbiology 

48:556-560; 1984. 
SOIL PHYSICAL AND CHEMICAL PROPERTIES ASSOCIATED 

WITH THREE SITE PREPARATION TECHNIQUES AND THEIR 

EFFECTS ON GROWTH AND SURVIVAL OF SEEDLINGS IN 

NORTHERN IDAHO= 

ABSTRACT 

Survival of outplanted western white pine and 

Douglas-fir is often hampered by droughty soil 

conditions in the northern Rocky Mountains. This 

study was initiated to compare soil properties from 

three site preparation techniques and to assess the 

impacts on seedling survival and growth for a 

relatively dry planting site and a moist planting 

site. Surface organic matter and mineral soil were 

mechanically mounded to form raised planting beds 

on two cedar-hemlock sites in the northern Idaho 

D. S. Page-13umroese2, M. F. ~urgensen~, R.T. ~raham~, panhandle region. Soil properties and seedling 

A.E. ~arvey~ growth resulting from this treatment were compared 

with scalped and minimum scarification treatments 

on both sites. 

Organic matter content was significantly (P<0.05f 

altered by site preparation, as was bulk density, 

Nutrition in the soil was improved in the raised 

planting beds. An increase in volume of organic 

matter in raised beds acted as mulch, thus 

retaining subsurface moisture and moderating soil 

temperature. Seedling top growth was not 

significantly altered the first year, but nutrients 

in the foliage were significantly increased in the 

mounded treatments. Rooting depth was also greater 

in the mounds. Bedding the soil was most 

beneficial on the site with low organic matter and 

warm, dry soils. On the site with moderate 

moisture and good soil, the minimally disturbed 

treatment was just as productive as the raised 

planting bed treatment. 

KEYWORDS: Site preparation, bedding, scalping, 

soil physical properties, soil chemical properties. 

Historically, artificial regeneration in the 

Pacific Northwest has been unsatisfactory on sites 

with low soil moisture, high evaporative demand and 

low nutrient status (Haig and others 1941; Foiles 

and Curtis 1973). On such sites adequate stocking 

levels may be achieved through mechanical site 

preparation which provides favorable microsites for 

moisture and nutrient accumulation and reduction of 

vegetative competition (Wellner 1976). Use of 

scalping, burning, scarification or a combination 

of these are effective for ease of planting, but 

survival is often poor (Beebe 1982). Site 

preparation techniques that utilize mounding of 

surface organic and mineral soil have been 

effective elsewhere (Worst 1964; Wilhite and 

Harrington 1965; McMinn 1969; Shultz and Wilhite 

1974; 

Francis 1979; Frederick and others 1984). This 

technique concentrates limited moisture and 

nutrients into the planting zone for more effective 

seedling uptake. 

In northern Idaho and the Pacific northwest in 

general, the growing season is characterized by 

harsh growing conditions, including drought and 

extensive heat, which can markedly reduce seedling 

performance especially for high value species such 

as Douglas-fir (Pseudotsuga menziesii var. glauca 

[Mirb.] Franco) and western white pine (Pinus 

monticola Dougl. ex D. Don). Mounding mineral soil 

and surface organic matter may alleviate much of 

the environmental stress imposed on seedlings in 

this area. This study was initiated to compare 

potential effectiveness of mounding to commonly 

used site preparation techniques which are utilized 

for alleviating environmental limitations to early 

seedling perfomance. 

'presented at the Symposium on Current Topics in 

Forest Research, Gainesville, FL. 

MATERIALS AND METHODS 

2~oil Scientist Trainee, Research Forester, and 

Project Leader, respectively, Intermountain 

Research Station, U.S. Department of Agriculture, 

Forest Service, Moscow, ID 83843. 

3~rof essor of Forest Soils, Department of 

Forestry, Michigan Technological University, 

Houghton, MI 49931. 

Location 

Two sites, located on the Priest River 

Experimental Forest near Priest River, ID, were 

used for this study. One site is located at an 

elevation of 715 m above sea level on a flat 
bench adjoining the Priest River. It is the wamer 

and drier of the two sites. The habitat type is 

classified as Abies grandis/ Symphoricarpos albus 

(Cooper - and others in preparation] and the soil is 

classified as Andic Xerochrept. Annual 

precipitation averages 83-8 cm, with a mean annual 

teqerature of 6 .eQ6 {Finklin 1983) . 

Site 2 is at an elevation of 1 456 rn above sea 

level, The slope angles range from 10 to 35 

percent and have north-to-nertheast aspects. The 

haitat type is classified as Tsuqa heterclphylla 

[Cfintonia uniflora (Cooper and others in 

prqarationf and the soil is classified as a Typic 

Cryorthent, This area is considered a productive 

forest site, Annual precipitation at this 

elevation is 92.3 cm and the mean annual 

temperature is 5.3"C (Ficklin 1983) . 

Treatments 

Two randomized complete block experiments were 

est&lished, one on each site, At the low 

elevation site there were three treatments with 

four replications, and at the high elevation site 

there were three treatments replicated three times, 

The high elevation site was divided into three 

separate 1-ha areas, each was cleareut, and had 

approximately the same slope, aspect, soil, and 

habitat type. The treatments consisted of: 

1. Mound--mixing the top 10 cm of mineral 

and organic soil into beds 

approximately 46 an high and 30 m long. 

2. Scalp--removal of the top 20 cm of 

mineral and organic soil by machine. 

3. Minimal disturbance--essentially 

undisturbed after harvesting. 

Each treatment was planted with either 

containerized Douglas-fir or western white pine 

seedlings at a 31 x 46 cm spacing with 228 trees 

per treatment. Trees were grown in 4 em3 cells at 

the U.S.D.A. Forest Service, Coeur d%lene Nursery, 

Goeur dfAlene, ID. The Douglas-fir and western 

white pine utilized were adapted to each of the two 

elevations. 

Sampling 

Soil samples and seedlings were collected from 

each treatment four times during the growing 

season. Soil smples were collected from 15 

randomly selected microsites within each treatment, 

to the maximum depth of the rooting zone. These 

smples were categorized by soil type based on 

their organic/mineral composition, Temperatures 

were t&en of each soil category under eaeh 

seedling. Bulk density samples were taken at 

depths of 0 to 5 cm, 10 to 15 cm, and 20 to 25 cm 

at five random points in eaeh treatment, Fifteen 

seedlings were measured for height and total 

rooting depth. 

All soil smples used for chemical and physical 

analysis were passed through a 2-m sieve. Bulk 

density and moisture content sapless were dried at 

105°C for 24 hours. Organic matter was determined 

by weight loss after combustion at 

375OC for 26 hours. Ca, Mg, and K were extracted 

with 1 amuniurn acetate adjusted to pH 7.0 and 

detemined using atomic absorption techniques 

(Black 1965). Soil pH was determined using 1:2 

soi1:water mix. Total soil nitrogen and 

phosphorous were detemined by block digestion and 

analyzed using Technicon AutoAnalyzer techniques 

(Brenrner 1965) . 

For Ga, Mg and K deteminations, foliage was 

ashed and extracted using 2 g nitric acid. Analysis 

was perfomed hy atomic absorption techniques, 

Total foliar nitrogen and phosphorous were 

detemined after block digestion and analyzed using 

Technicon AutoAnalyzer techniques. 

An analysis of variance was conducted on the 

data, utilizing a randomized complete block design, 

The treatment means were separated using Duncan's 

multiple range test. 

RESULTS ANZ) DISCUSSION 1 

Soil Physical Properties 

Mounding the organic and surface mineral soil 

layers had a Large impact on soil physical 

properties, The changes that occurred were usually 

associated with the degree of diseurbance. The 

mounded treatments at both sites had significantly 

jP<0.05) more organic matter than the scalped 

treatment as can be seen in table 1. 

The minimally disturbed treatment was not 

significantly different from the mounded treatment 

because this treatment was maintained as 

undisturbed as possible and much of the organic 

matter was left intact. The higher levels of 

organic matter in these two treatments are also 

reflected in lower bulk densities at both sites, 

The minimally disturbed treatment showed a slight 

increase in bulk density with depth because it was 

not layered with organic matter as was the mounded 

treatment (table 2). Soil density in the scalped 

treatment also increases significantly with depth. 

This is probably because organic matter was removed 

and soil particles were somewhat compacted. Mixing 

of the organic matter with the mineral soil in the 

mounds improved aeration of the treatment and can 

be seen in the lack of hulk density change 

throughout the profile. 

Table 1,--Organic matter (%) for each elevation and 

trea-tn\ent 

Minimal 

Site Mound Scalp disturbance 

Low elevation 15.0a 9.4b 14,4a 

Nigh elevation 27.5a 14.5b 29.2a 

Different letters indicate significant differences 

(P<0.05) across treatments, 
T&le 2,--Bulk density (g/cc) means at three depths 

from both elevations 

Minimally 

Mound Scalp disturbed 

Low elevation 

5 crn 0.7a 0-9a 0.Ta 

15 em 0.7a 1, LS o , ac 

25 cm 0,7a 1,3b 0.8~ 

High elevation 

5 cm 0.523 9 - 9b 0.5a 

15 crn 0.6a g.9b 0.7s 

25 cm 0,6a 1.0b 0-8s 

Different letters indicate significant differences 

/P<0,05j across treatments. 

Concentrating organic matter and surface mineral 

soil into mounds increased the moisture content of 

the soil in the rooting zone at the high elevation 

(table 3). This was most evident during the peak 

growing months of July and August. Only small 

differences in moisture content between treatments 

were detected at the low eievation site, 

At the low elevation the scalped treatment had 

less soil moisture than the high elevation during 

all the sample dates except September, At the high 

elevation site, Large soil moisture differences 

occurred among treatments, particularly the mounded 

and scalped treatments, These differences were 

likely caused by the increase of organic matter in 

the mounds, which increased moisture holding 

capacity by improving soil structure and porosity. 

Soil temperature data were recorded throughout 

the growing season, however mounding had little 

Table 3.--Moisture content (&) in the rooting zone 

for each treatment and sample date 

Minimally 

Sample Mound Scalp Disturbed 

Low elevation 

June 37-76 36,9b 39,6a 

July $6, 7a 34.2b 46,!3a 

August 49.3a 46.6a 48.923 

September 37. P,b 39.7b 36,5b 

High elevation 

June 37.5B 39,Ba 36.5b 

Zuhy 81-8a 53 -6a 86.4a 

August 7l.3a 45.fb 65,5b 

September 66.6a 46.4b 76.5a 

effect on it. The temperatures at the high 

elevation averaged 3-4OC lower than those at the 

lower elevation from June to August. Lower 

temperatures were expected in the mounded 

treatments because moisture content is positively 

related to organic matter content and inversely 

related to temperature {Shultz and Wilhite 1974; 

Morris and Pritchett 19831. Curing the summer oT 

1983, rainfall at the low site exceeded the 75-year 

average by 9-8 cm and at the high site by 14.6 cm. 

Thls heavy rainfall throughout the growing season 

is believed to have negated any major effect of 

moundlng on temperature or moisture content. 

Soil Chemical Properties 

The soil chemical properties were also affected 

by concentrating organic matter into mounds. 

However, in many cases the differences were not 

significant. Soil acidity differences were found 

between the scarified treatments and the mounds at 

the high elevation and could be attributed to a 

greater component of decayed wood. The low 

elevation soil generally had a higher pH than the 

soil at the high elevation and this difference is 

likely due to base cycling by grasses present at 

the low site. There were no significant differences 

between calcium, magnesium or potassium between 

treatments during the first growing season. 

Mounding surface organic matter and mineral soil 

significantly changed the concentration of total 

nitrogen in the soil profile. At the lower 

elevation the highest percentage of total nitrogen 

was found in the mounded treatments and the lowest 

percentage in the scalped treatments (table 4). 

This was a reflection of soil organic matter 

content. The high elevation treatments had a 

greater percentage of total nitrogen than the low 

elevation treatmemts. Some of the differences may 

be accounted for by the large quantity of undecayed 

wood that was incorporated into the mounds at the 

high elevation. 

Table 4.--Total nitrogen and total phosphorous 

concentrations (%) in the rooting zone as 

affected by site treatment (all strata 

types combined) 

Minimally 

Mound Scalp disturbed 

Low elevation 

Total Nitrogen .27a .12c .18b 

Total Phosphorous .28a .2 5b .29a 

High elevation 

Total Nitrogen -3 la -3 4a -2 8b 

Total Phosphorous .Zla .13a .15a 

Different letters indicate significant differences 

(P40.05) across treatments. 

Different Letters indicate significant differences 

(P<0.05) across treatments. 
The lowest concentrations of total phosphorous at 

the Low elevation were zn the scalped treatment and 

are due to the removal of organic matter (table 4). 

In general, higher phosphorous eoncentratlons were 

present at the low elevation than at the hlgb 

elevation, Srnce the malority of organlc 

phosphorous cornpo~nds become available through the 

decay of fresh vegetation (Alexander i977), the 

hlgher values at the low elevation can be 

associated wlth the incorporation of grasses into 

the mounds. At the hlgh eievatron the Pow sol1 pH 

values may also be lrrztrng the release cf organic 

phosphorous into the soil (Alexander 1977), 

Greater organic matter levels at the higher 

elevation may result in more phosphorous release, 

but ~t nay be immediately tied up because of a high 

carbcn/phosphorous ratio. 

Seedling Growth Response 

Rooting depth at the end of the growing seascn 

was most affected by physical changes In the soil 

(table 5). Douglas-fir and western white pine 

appeared to occupy about the same amount of below 

ground volume, indicating there was no species 

difference, However, there were treatment 

differences. Seedlings from the mounded treatments 

had the greatest rooting depth and, except for 

western white pme at the high elevation site, the 

mound seedlings had significantly deeper roots than 

the scalped treatment, In general, seedlings from 

the scarified treatment had a greater rooting depth 

thac the seedlings from the scalped, although not 

significantly so, This result nay have been due to 

less compaction in the scarified treatment and, 

therefore, easier root penetratron. 

Seedling height growth was unaffected by the site 

preparation techniques (table 6) largely due to the 

abundance of rainfall. and predetermined growth from 

the bud. However, there were signifxcant 

differences in total nitrogen at the end of the 

growing season in Douglas-fir foliage (table 71, 

Differences in total nitrogen can be attrrbuted to 

Table 5.--Total rooting depth icmf for each 

treanent 

and species at the end of the first 

growing season 

Minimally 

Mound Scalp disturbed 

Low elevation 

White pine 25, la 21.9b 20 4I; 

Do~glas-fir 23-92 19,7b 21,4aS 

High elevation 

White pine 23.3~1 20.9~1 20,8a 

Douglas-fir 23-9a l8,4k 20,3k 

Different letters indicate significant differences 

fP<0,051 across treatments. 

Table 6,--Total tree height (ern) at the end of the 

first growing season 

Minimally 

Mound Scalp disturbed 

-------------- eJp'---------------- 

Low elevatron 

White pine 7,7a 7.4a 7,Oa 

DcugLas-flr I5,iia 15,9a 15,2a 

High elevation 

idhike pine 7,6a 6,la ?,6a 

Douglas-fir 15,7a 15-43 14,6a 

be~ter growing conditions in the mounds during 

1983. Thls improved nutrient status should be 

reflected In l9e4 growth. Western white prne 

showed no response to the treatments in terms of 

first year ?erfomacee, This result is probably 

related to better ada~tability of che species to 

harsh environments, as compared to Douglas-fir. 

There were no significant differences in the uptake 

of totai phosphorous, calcium, magnesium, or 

potassium. There were, however, higher values for 

these cations at the low elevation site probably 

because of rapid base eycllng by the grasses. 

CONCLUSION 

The results cf moundlng SOIL organic matter and 

~lneral sol1 as a site preparation technique were 

varled Ln thls experlrnent, Fs expected, organic 

matter levels were hzgher Ln the mounded treatment 

thar* in the scalped treatrnect and would lead to 

greater microcrganlsrn act~v~ty and, hence, 

increased nctrrent avallahllity, 

If the weather conditions for the first year of 

thrs study had been more droughty, differences of 

moisture and temperature nay have been more evident 

between the scalpe2, scarified, and mounded 

treatments. These temperature and moisture 

Table 7,--Percent total nitrogen iri the foliage at 

the end of the growing season 

Minimally 

I.lound Scalp disturbed 

------------- ~prcent------------- 

.L - Low elevation 

White pine 1,25a 16,22a 1, lOa 

Douglas-fir 1,17a -13 3b 1, i2ab 

High elevation 

White pine 1, 01a -9Oa b,03a 

Douglas-fir 1,18a -7 2h l,33a 

Different letters indicate significant differences 

(P<0,051 across treatments, 
changes would then make the differences in chemical 

properties and seedling growth more pronounced from 

the release of more nutrients from organic matter, 

Based on. these first year results some management 

strategies for the Pacific Northwest can be 

addressed* In areas where moisture and nutrients 

are not limiting, as at the high elevation site, 

there is no need to prepare the site intensely. 

Leaving the organic matter and decayed wood intact 

will produce favorable seedl~rig growth. However , on droughty sites with competition problems the 

benefits of mounding are twofold, First, mounding 

creates a soil profile with lower soil density and, 

therefore, allows greater root penetration. 

Second, mounding ~roduces a microsite of increased 

moisture holding capacity and nutrients for 

seedling growth. 

This study will be continued for two more years 

in order to discern some of the long range effects 

of mounding on soil properties and tree growth, 

Other studies with mounding the soil mineral and 

organic layers will include fumigating the soil to 

test for beneficial organisms in the rooting zone 

and soil/seed manipulation to improve first year 

survival, 

ACKNOWLEDGMENTS 

The authors wish to thank Howard Lowenstein, Dave 

Adams and Jonalea Tonn for their help in preparing 

this manuscript. 

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Rotuba, New Zealand: international Union of 

Forestry Research Organizations; 1983: 589-596. 

Haig, I. T.; Harris, D, P.; Weidman R. H. Natural 

regeneration in the western white pine type. 

Technical Bulletin 767. U.S. Department of 

Agriculture, Forest Service; 1941. 99 p. 

McMinn, J. We Preparing sites for pine plantings in 

southern Florida, Research Note SE-117. 

Asheville, NC: U.S. Department of Agriculture, 

Forest Service, Southeastern Forest Experiment 

Station; 2369. 5 p. 

Morris, L. A.; Pritchett, W. L, Effects of site 

preparation of Pinus elliottii-Pinus palustris 

flatwoods forest soil properties. In: 

Proceedings, symposium on forest site and 

continuous productivity; 1983; Portland. 

Portland, OR: International Union of Forestry 

Research Organizations; 1983: 243-251. 

Shultz, R, P.; Wilhite, L. P, Changes in a flatwood 

site following intensive preparation. Forest 

Science 20: 230-237; 1974, 

Stewart, R. E. Site preparation. In: Cleary, B. D.; 

Greaves R. D.; Hermann, R. K. eds. Regenerating 

Oregon's forests: Proceedings of a symposium; 

1978; Corvallis, OR: Oregon State University 

Extension Service; 1978: 99-129. 

Wellner, C. A. Frontiers in forestry researchPriest River Experiemtal Forest, 1911-1976. 

Ogden, UT: U.S. Department of Agriculture, 

Forest Service, Intemountain Forest and Range 

Experiment Station; 1976, 148 p. 

Wilhite, L. I?.; Warrington, T. A. Site preparation. 

In: WiLhite, L. P.; Harrington, T. A. eds. A 

guide to loblolly and slash pine plantation 

management in southeastern U.S.A. Report 14. 

Atlanta, GA: Georgia Forest Research Council; 

1965 : 230-237. 

Worst, R. K. A study of effects of site preparation 

and spacing on planted slash pine in the coastal 

plain of southeastern Georgia. Journal of 

Forestry 62: 556-560; 1964, 
The Use of Senescent Cultures of Postia placenta, 

Gloeophyllm saepiariurn, and Gloeophyllm trabem 

in the Study of Wood ~eca~l 

J. A. Micales and T. Z. ~ighle~~ 

Brown-rot decay fungi play a major role in the 

decomposition of wood and wood products. Unlike 

the white-rotting Basidiomycetes, brown-rot furagi 

are able to metabolize the cellulose and hemicellulose of wood but are unable to substantially 

metabolize lignin (Kirk and Cowling 1984). The 

mechanisms by which this is done are largely 

unknown. Brown-rot fungi produce several kinds 

of extracellular carbohydrate-degrading enzymes 

(Highley 1977; Kighley and Wolter 1982; 

Ishihara and Shimizu 1980, 1984; Ishihara and 

others 1978); the role of these enzymes in the 

process of wood decay has not been fully 

explained (Kirk and Cowling 1984). A better 

understanding of the biochemistry of brown-rot 

fungi could result in the development of specific 

metabolic controls which could prevent or inhibit 

decay, thus replacing highly toxic preservatives. 

One possible way to study the biochemistry of 

wood decay is to examine the physiology of cultures which have lost the ability to degrade 

wood. Most Basidiomycetes are fairly stable 

in culture due to their dikaryotic state. 

Occasionally, isolates change in culture; they 

become less vigorous and are unable to decay 

wood. Such senescence in fungi is poorly understood and has been associated with fungal 

 TO be presented at the symposium "Current 

Topics in Forest Research: Entphasis on 

Contributions by Women Scientists." 

Nov. 4-6, 1986, Gainesville, FL. 

ZResearch Plant Pathologist and Project 

Leader, respectively. U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory, One Gifford Pinchot Drive, 

Madison, WI 53705-2398. 

Abstract.--The brown-rot frulgi Postia placenta, 

Gloeophyllm saepiarium, and 5. trabeum are 

economically iqortant decayers of wood. These 

organisms metabolize the cellulose and hemicellulose of woody tissues but do not substantially metabolize lignin. Senescent cultures 

of these species lose their ability to degrade 

wood and are thin and appressed compared to the 

more robust, floccose eonsenescent isolates. The 

physiology and growth habits of these senescent 

cultures were compared to nonsenescent isolates 

in order to study the biochemical mechanisms of 

wood decay. No significant differences were 

fouad in growth rates of senescent and nonsenescent cultures on malt-extract agar. Senescent 

isolates retained the ability to produce 

g-D-glucosidase, a- and 6-D-galactosidase, 

xylanase, endo-@-I,&-glucanase and other 

cellulose-degrading enzpes. These data suggest 

the hypothesis that additional chemical or biochemical mechanisms besides simple enzpatic 

degradation are involved in wood decay by 

brown-rot fungi. 

Keywords: Brown rot, carbohydrate-degrading 

enzpes, Basidiomycetes, senescence. 

viruses (Day and Dodds 1979, Lemke 1977, Hanrmter 

and others 1986, Castanho and others 1978), 

bacteria- or mycoplasma-like organisms (Wilson 

and Hanton 1979), and specific chromosomes 

working in conjunction with plasmids (Esser and 

others 1984; Esser and Tudzynski 1979). A 

comparison of the physiology of senescent and 

nonsenescent cultures of brown-rot fungi should 

further our understanding of the decay process. 

The objective of this study was to determine 

whether certain cultural characteristics and the 

production of extracellular carbohydratedegrading enmes are related to senescence, and 

thus required for wood decay. 

MATERIALS m MErnODS 

Maintenance of Fungal Cultures 

A11 cultures were maintained on 2.0 percent 

malt-extract agar (PIEA) slants stored at 4 OC. 

Sources and dates of collection of all cultures 

are presented in table 1. 

Identification of Senescent Cultures 

Representative isolates of Postia placenta (Fr.) 

M. J. Larsen and Lombard [syn: Poria placenta 

(Fr.) Cke.], Gloeophyllm saepiarium (Wulf.: 

Fr.) Karst. and 5, trabeum (Pers.: Fr.) Murr. 

were evaluated for their abilities to cause wood 

decay by the standard ASTM soil block method 

(ASTM 1971) using southern pine blocks (25.4 by 

25.4 by 3.2 m, the long axis parallel to the 

grain). Soil block bottles were maintained at 

27 OC and 70 percent relative huidity; the percent 

weight loss of each block was detemined after 

12 weeks. Isolates which caused weight losses of 

less than 35 percent were considered "senescent." 
This was an arbitrary value and represents a 

reduction in decay capacity of about 50 percent. 

Rate 

Senescent and nonsenescent cultures of each of 

the three species were grown on 2 percent =A; 

gross colony morphology and light microscopy 

of individual hyphae were observed after 3 weeks. 

Growth rates were determined by inoculating 

2 percent HEA with 5-m plugs taken from the 

margins of 7-day-old cuLtures also grown on 

2 percent PIEA, Radial growth of each colony 

was measured after 2, 6, 11, and 13 days. 

Cultures 

Senescent and nsnsenescent isolates sf each 

of the three species were grown in 25-mP 

stationary liquid cultures in 250-m1 Erlemeyer 

flasks with 0.5 percent ceklobiose in a basal 

salts solution (Nighley 1993) as the growth 

medim. In a second experiment, the fungi were 

grown in the same basal salts solution amended 

with I percent sweetgw sawdust with or without 

0.5 percent ceZPsbiose as a supplemental carbon 

source. Control flasks contained the basal 

salts solution alone. The liquid media were 

inoculated with 5-m mycelial plugs taken from 

the margins of 7-day-old colonies grewn on 2 percent mA- Culture filtrates were collected by 

vacuum filtration and dialyzed overnight against 

distilled water in 12,000 to 14,000 Dalton 

Spectrajpss dialysis tubing. Culture filtrates 

were then assayed for general extracellular 

proteins (Lowry and others 1951) using dilutions 

of bovine serw albuglia for the standard curve, 

The activities of a-D-galactosidase (E.C. 

3.2.1.22), &-B-galactosidase (E.C. 3.2.1.23) and 

B-D-glucosidase (E.C, 3.2.1.21) were determined 

by the liberation of p-nitrophenol from the 

respective p-nitrophenol substrate (Nelson 1944)- 

One unit of enzpe activity was defined as the 

amomt sf eazpe needed to release I pH of 

p-nitrophenol per hour at 40 OC, 

The activities of ends-g-l,4-gbucaaase (carbo~ethyleellulase) (E,C. 3.2.1.4) and endop-1,4-xylanase (E.C. 3.2J.37) were assayed by 

measuring the increase in reducing groups using 

Nelson's modification of the Somogyi method 

(Nelson 1944). One unit sf enzpe activity was 

defined as the amowt of enzyrne needed to 

liberate reducing power equivalent to 1 of 

glucose per 24 hours at 40 OG. 

Cellulolytic enzpe activity was also measured 

by the degradation cellulose-azure as described 

by Highley (1983). Senescent and aonsenesceat 

isolates of each of the three species were 

grom inr vertical tubes of a basal salts medim 

(Nighley 1973) on which sterilized celluloseazure had been aseptically layered. Eazpe 

activity was estimated by the amouret of dyed 

cellulose degradation products released into the 

agar medim. The intensity of color was estimated on a O to 4 scale, with O representing no 

coboration (i.e. no cellulase activity) and 4 

representing an intense blue color (i-e. high 

levels of ceblulase activity). 

Chemicals 

CarboxyllretbylcePLu1.ose was obtained 

Prom Hercules (Wilaiagton, DE); all other chemicals were purchased from Sigma (St. Louis, MO). 

Identification of Senescent Cultures 

The 15, 16, and 16 isolates of P. placenta, . . 6, - and 6. traberzlrm, respectively, we r for their abilities to decay wood; 

percent weight bosses of southern pine test 

blocks are presented in table 1. Some isolates 

sbo eased decay capacity. These were: 

P. --ME20, ME387; 6. saepiarim--m517, 

k483, MAD536, TA13; G. trabeurn--MAD5096-15, 

KPSP539s, TP354b. These cultures were termed 

"senescent" ad wwer used in all subsequent 

tests with representative nonsenescent strains. 

and Growth Rate 

The colony morphologies of senescent cultures 

differed from those of the nonsenescent isolates. Colonies produced by senescent cultures 

were thin and appressed coinpared to the more 

robust, floccose wild strains. Senescent 

isolates of 6. trabem and 6. saepiarim also 

failed to produce the characteristic pigments 

fomd in nonsenescent cultures. Hflhae of 

senescent isolates were swollen and distorted. 

A large degree of growth rate variation 

occurred among isolates of each of the three 

species. Growth rate was not related to 

senescence (figs. 1-3); certain senescent isolates (m387, MD483) actually grew more rapidly 

than nonsenescent cultures of the same species. 

Growth and Enzyme Production in Liquid Culture 

Senescent and nonsenescent isolates of 

P. - , 5. saepiarium, and 2. trabeum were grown in a basal salt solution with 

0.5 percent cellobiose as the carbon source. 

Culture filtrates were assayed for the presence 

of a- and B-D-galactosidase, @-D-glucosidase, 

endo-@-1,4-xylanase, and endo-p-1,4-glucaaase 

(carboxymethylcekluIase]; dry weights of the 

mycelia and pH's of the culture filtrates were 

also determined (table 2). All cultures dramatically lowered the pH of the culture filtrates 

from an initial reading of 4.5. In most cases, 

the extent of this decrease was related to the 

dry weight of the fungus; isolates which formed 

the greatest amount of mycelium produced the 

lowest pH readings (MAD537s, MAD539s, NE20). 

Total extracellular protein production 

appeared to Be independent of dry weight and 

was characteristic of each species, Isolates 

of 6. formed low levels of 
Table 1.--Collection data on isolates of Postia 9 and 6. trabem 

ranked by their ability to degrade southern pine as esthated by the ASTl"f soil-wood block assay 

Species Isolate nmber Date of Source and location Weight 

collection of collection loss 

Mo/yr 

Postia placenta (Fr.) M. 5. Larsen 

and Lombard TR1;2556 

RLG3760R 

3/50 Mineshaft support, Transvaal, 68.2 

Africa 

7/63 Betula Britton, 65.4 

Newcomb, W 

Pinus Laws, , Coronado 65 a 4 

National Forest, AZ - - 62,o 

menziesii (Hirb. ) 60.8 

Fraaco. Orepoa " 

Pseudotsuga meaziesii, yacht 60.4 

'%ericaft 

Pseudotsuga meaziesii, 60.3 

Clark County, WA 

Telephone pole, Clark County, 60.0 

rvJA 

Conifer sills and piles, 59.5 

Fairfield, OH 

Pseudotsuga menziesii, Oregon 59.4 

PhiladePobia. PA 58.3 A ? 

Pinus sg., Madison, WI 57.2 

(Raf . ) 52-5 

Sarg., Madison, WI 

Pole, Willarnette Valley, OR 6-5 

Fko.or planking, Pleasant 5.1 

Hill, 68 

Gloeophyllum saepiarium (Wulf.: 

Fr.) Karst FD18 1961 meaziesii, 61.1 

NAD537s 1920 Railway ties, Arkansas 59.4 

FP100242sp 9/52 Picea eagelmaanii Parsy, 57.8 

White River National Forest, 

ME79 10/62 heterophylla, Cowallis, 57.2 

OR 

Tsuga sp., Corvallis, OR 

Telephone pole, South Dakota 

~iceH enReimanni or Abies 

concolor (Gord. & Glend.) 

Lindl., McCall, ID 

lawsoniana 

(A- Murr.) Parl. 

Pseudotsuga menziesii, 

Albany, OR 

Pinus sp-, Gulfport, MS 

Tsuga sp,, Hunt Couaty, PA 

Pinus contorta Dougl., 

Gulfport, MS 

6/74 Picea glauca var. albertiana 32.9 

(S. Brown) Sarg. ... - - - 31e3 

3/22 Picea sp,, Madison, MI 28.7 

7/63 Pinus sp., Syracuse, NY 14.6 
Table 1.--Collection data on isolates of Postia placenta, Gloeophyllum saepiarium and 5. trabeum 

ranked by their ability to degrade southern pine as estimated by the ASTM soil-wood block assay--con. 

Species Isolate nmber Date of Source and location Weight 

collection of collection loss 

trabem (Pers . : 

Fr.) Murr- ME39 7/61 Sequoia sempenrirens (D. Don) 66.3 

End1 . , Akron, OX 

MBr) SAVO IS 11/51 Pseudotsuga menziesii, "Savo 63.2 

Island" aircraft carrier 

DAOM-F3823 4/65 Unidentifiedhardwood, 63.0 

Ottawa, Ont. 

MD7 6 - - - - 62.1 

FP125076sp 5/62 Acer sp., West Alton, NH 62.1 

W617 6/26 Thuja plicata DOM, 60.8 

Madison, WI 

ME76 2/63 Plywood flooring, Madison, WI 59.2 

MD5 05 4/62 Pinussp.,Madison,WI 51.3 

1320 8/64 Unidentified hardwood, 48.1 

Routt County, UT 

TA- 1A 6/63 Syracuse, NY 48.1 

MD256 - - - - 43.9 

ME509 10172 Pseudotsuga menziesii, 37.1 

Racine, WI 

OPSAL860 1 6/63 Telephone pole, South Dakota 35.8 

MAL15096- 15 - - Pinus sp., Bogalusa, LA 25.0 

MAD539s 3/24 Pinus sp., Madison, WI 3.6 

TP356b 1938 Pinus sp., Spartanburg, SC 1.2 

Figure 1.--Radial growth (m/da) of senescent 

and nonsenescent isolates of Postia placenta 

on 2 percent malt extract agar. Solid line = nonsenescent cultures; broken line = senescent 

cultures. (HL86 5330) 

2 4 6 8 10 12 14 

TIME Id1 

Figure 2,--Radial growth (m/da) of senescent 

and nonsenescent isolates of Gloeophyllum 

saepiarium on 2 percent malt extract agar. 

Solid line = nonsenescent cultures; broken 

line = senescent cultures. (ma6 5331) 
2 4 6 8 10 12 14 

TIME Idl 

Figure 3.--Radial growth (ilsmlda) of senescent 

and nonsenescent isolates of Gloeophyllum 

trabem on 2 percent malt extract agar. 

Solid line = nonsenescent cultures; broken 

line = senescent cultures. (ML86 5332) 

extracellular proteins; enzyme production by 

G. trabem isolates was much higher, and -- 

cultures of P. placenta exhibited an intermediate response. A few exceptions to this 

pattern were noted. Certain senescent isolates 

of 6. trabeum (MAD539s and TP356b) and 

P. - placenta (ME3871 produced lower levels of 

extracellular proteins than the nonsenescent 

strains of each species. Another senescent 

isolate of P. placenta, ME20, produced 

extremely high levels of extracellular proteins. 

There was no apparent relationship between 

senescence and levels of glycosidase production. Enzyme levels were extremely variable 

mong the different isolates of each species; 

senescent cultures typically produced equivalent or higher levels of f3-D-glucosidase, 

a-D-galactosidase, and p-D-galactosidase than 

their nonsenescent ccuaterparts. Isolate m20, 

a senescent culture of P. placenta, produced 

extremely high levels of these enzymes, There 

did appear to be some correlation between 

xylanase production and senescence of P. placenta 

and 5. trabeum; senescent isolates of these 

species produced aberrant levels of this enzyme. 

Isolates ME387, MAD5096-15, MAI)539s, and TP35Sb 

produced decreased quantities of xylanase compared to the nonsenescent strains; isolate ME20 

produced much higher levels of xylanase than the 

remaining isolates of P. placenta. No correlation was found between senescence and the 

presence of endo-@-1,4-glucanase, although 

senescent isolates MAT1539s aad TP356b (G. trabeum) 

produced slightly lower quantities of this 

enzyme than the nonsenescent strains. 

Senescent and nonsenescent isolates of the 

three species were also able to grow in a basal 

salt medium supplemented with 1 percent sweetgum 

sawdust (table 3). Fungal hyphae were observed 

to grow on and around the sawdust particles and 

gathered the sawdust into a loosely connected 

mat. Mycelial growth was greatly stimulated by 

the addition of 0.5 percent cellobiose. This 

increase in growth is reflected in the lower pH 

values and increased levels of extracellular 

proteins produced by most isolates in the 

presence of cellobiose. 

As in the previous experiment, there was no 

correlation between levels of f3-D-glucosidase, 

a- and f3-D-galactosidase and senescence. The 

addition of cellobiose to the medium generally 

increased glycosidase production, but it is 

unknown whether this was due to increased 

amounts of mycelial growth or whether additional 

quantities of enzyme were induced. All isolates 

of g. saepiarium produced extremely low levels 

of a-D-galactosidase with or without the addition of cellobiose; this trait appears to be 

characteristic of the species. Certain isolates 

of 5. trabeum (MAD617, kAD539.5, TP356b) produced 

much lower levels of f3-D-galactosidase in the 

presence of cellobiose; this phenomenon was not 

confined to senescent cultures, 

Production of xylanase and endo-8-1,4- 

glucanase also appeared to be largely. independent of senescence. Xylanase production by 

isolates of P. placenta generally increased 

with the addition of cellobiose with the exception of isolate ME387, a senescent culture. 

Levels of xylanase declined upon the addition 

of cellobiose for isolates of 5. saepiarium 

and were generally unaffected for isolates of 

G. trabeum. The ienescent isolates of g. -- 

trabeum expressed decreased levels of xylanase 

production with and without the addition of 

cellobiose. This is consistent with the results 

obtained in the previous experiment. Levels of 

endo-f3-1,4-glucanase production generally 

increased with the addition of cellobiose for 

isolates of P. placenta and were unchanged for 

most isolates of G. saepiarium and g. trabeum. 

Certain senescent isolates of g. saepiarium 

(MAD536, TA13) and 5. trabeum (MAD539s, TP356b) 

showed a decline in endo-@-1,4-glucanase production upon the addition of cellobiose. 

There was no relationship between senescence 

and the production of cellulase as measured 

by the degradation of cellulose azure (table 4). 

The senescent isolates of g. placenta, ME20 and 

ME387, produced extremely low quantities or no 

detectable levels of this enzyme, but several 

nonsenescent isolates with good decay capacity 

(MAD4874, MD506, TRL2556) were also poor enzyme 

producers. Senescent isolates of 5. saepiarium 

(TA13, MD483, ME517) and t;. trabeum (MAI)539s, 

TP356b) produced high levels of cellulolytic 

enzymes; isolates of these species which were 

poor cellulase producers (ME102, MAD536, 1320) 

exhibited little if any decreased ability to 
Table 2.--Fungal mass, pH of culture filtrate, and extracellular 

enzvme . uroduction A of senescent and nonsenescent isolates of 

Postia placenta, Gloeophyllum saepiarium, and g. trabeum after 

4 weeks in 0.5 percent cellobiose + basal salts solution1 

Isolate Dry weight pH Protein $-GLU~ GAL^ P-GAL~ XYL5 CHC~ 

POSTIA PLACENTA 

GLOEOPHYLLW SAEPIARIUM 

GLOEOPHYLLUM TRABEW 

ME39 29 2.78 114 0.042 0.030 0.028 556 112 

MAD Savo Is 27 2.98 73 0.030 0.028 0.009 516 80 

MAD6 17 14- 3.11 149 0.592 0.468 0.362 557 104 

MAD5096-15 12 2.97 138 0.680 0.101 0.111 291 100 

MAD539 s 29 2.62 25 0.174 0.100 <0.010 134 62 

TP356b 17 2.86 28 0.360 0.134 <0.010 257 61 

lAl1 readings represent an average of 5 replications. 

2j3-~LU = activity of 6-D-glucosidase. 

'u-GAL = activity of a-D-galactosidase. 

*B-GAL = activity of $-D-galactosidase. 

5~ = activity of endo-1,4-8-D-xylanase. 

6~~~ = activity of endo-1,4-$-D-glucanase (carboxymethylcellulase) . 

decay wood, with the exception of isolate 

MAD536. Cellulase production generally increased 

with time in all isolates and was not dependent 

on the presence of cellobiose in the medium. 

DISCUSSION 

A series of isolates of the brown-rot fungi 

P. placenta, G. saepiarium, and G. trabeum were 

evaluated for their ability to decay wood. 

There was a large variation in decay capacity; 

isolates which produced weight losses of less 

than 35 percent were considered senescent. 

Senescent cultures produced flattened, appressed 

colony morphologies; individual hyphae were 

often swollen and distorted. Senescence was 

not related to growth rate, length of time in 

culture, the ability of the fungus to lower the 

pH of liquid media, or the total production of 

extracellular proteins. Senescent cultures 

retained the ability to produce the carbohydratedegrading enzymes $-D-glucosidase, a- and p-Dgalactosidase, xylanase, endo $-1,4-glucanase, 

and other cellulolytic enzymes. Xylanase production seemed to be aberrant (i.e., higher or 

lower than nonsenescent isolates) in senescent 

cultures of P. placenta and 5. trabeum. Such 

aberrant levels of xylanase production suggests 

that the regulation or secretory mechanisms of 

these cultures may be impaired. The removal 

of hemicellulose occurs early in the process 

of wood decay (Kirk and Highley 1973, Highley 

and Kirk 1979); the production of xylanase is 

essential to this process. Further studies 

are needed to determine whether senescence in 

these species is dependent on altered xylan 

metabolism. 

If altered xylanase levels are not the major 

expression of senescence, the ability to decay 

wood must be dependent on more than the production of extracellular carbohydrate-degrading 

enzymes. Senescent cultures retained the ability 

to produce these enzymes in response to sawdust and cellobiose; it is unknown whether 

the enzymes are formed in response to solid 

wood. A nonenzymatic mechanism, involving 
Table 3.--Extracellular enzyme production and pH of culture 

filtrate of senescent and nonsenescent isolates of Postia placenta, 

Gloeophyllm saepiarium, and g. trabeum after 4 weeks on sweetgum 

sawdust (1 pct) in a basal salts solution 2 0.5 percent cellobiosel 

Isolate ~reatment~ pH Protein P-GLU~ a- GAL^ B-GAL~ XYL' CMC~ 

ME39 A 

B 

C 

MAD Savo Is A 

B 

C 

MAD617 A 

B 

C 

W5096- 15 A 

B 

C 

POSTIA PLACENTA 

GLOEOPHnLUM SAEPIARIUM 

GLOEOPWZLUM TRABEUM 
Table 3.--Extracellular enzyme production and pH of culture 

filtrate of senescent and nonsenescent isolates of Postia placenta, 

Gloeophyllum saepiarium, and G. trabeum after 4 weeks on sweetgum 

sawdust (1 pct) in a basal salts solution 1 0.5 percent cellobiosel-- 

con. 

Isolate Treatment2 pH Protein @-GLU3 ~-GAZ* $-GAL' XYL' CMC~ 

GLOEOPHYLLUM TRABEUM--con. 

l~ach reading represents an average of 3 replications. 

2Treatment A = Basal salts solution, B = Basal salts solution + 

1 percent sweetgum sawdust, C = Basal salts solution + 1 percent sweetgum 

sawdust + 0.5 percent cellobiose. 

3f3-GLU = activity of f3-D-glucosidase. 

4a-~AL = activity of a-D-galactosidase. 

5f3-~AL = activity of f3-D-galactosidase. 

'xYL = activity of endo-1,4-f3-D-xylanase. 

'CMC = activity of endo-1,4-f3-D-glucanase (carboxymethylcellulase) . 

hydrogen peroxide and ferrous ions, has been 

proposed to explain the rapid depolymerization 

of cellulose which occurs during brown rot 

(Koenigs 1972, Koenigs 1974a and b, Kirk and 

Cowling 1984); this proposal has not been 

proven (Highley 1982, Highley and Murmanis 

1985). The loss of such a nonenzymatic mechanism 

would explain why senescent cultures are unable 

to decay wood despite the production of 

carbohydrate-degrading enzymes. 

The debilitating agent associated with the 

senescence of these cultures has not been 

identified but appears to be transmissible 

(HighPey, unpublished data). The distorted 

hyphae of these senescent cultures resemble 

those of strains of Leucostoma cincta 

(Harnmar and others 1986) and Rhizoctonia solani 

(Castanho and Butler 1978) which contain dsRNA, 

the genetic material of fungal viruses. Experiments are currently underway to screen the 

isolates used in this study for dsRNA. The 

potential use of senescent cultures for the 

biological control of wood decay, as hypovirulent strains of Cryphonectria parasitica (Murr . ) 

Barr are used in the control of the chestnut 

blight fungus (Anagnostakis 1982), needs to be 

explored. 

ACKNOWLEDGMENT 

The authors thank Adrian L. Richter for his 

excellent technical assistance. 
Table 4. --Breakdown of cellulose-azure1 '2 by brown-rot fungi having different 

capacities to decay wood 

Cellulase activity 

Isolate Time (days) 

TRL2556 

RLG3760R 

L9138sp 

MD484 

MAD5 75 

MAD698 

ME48 

ME146 

FP100086sp 

MI28 1 

BTL-V- 10 

MD506 

MAD48 74 

ME387 

ME20 

m39 

MAD Savo Is 

DAOM-F3823 

MD76 

-- POSTIA PLACENTA 
Table 4. --Breakdown of cellulose-azure1" by brown-rot fungi having different 

capacities to decay wood--con. 

Cellulase activity 

Isolate Time (days) 

7 14 2 1 2 8 42 

- C +- c -C +C - C +C - C +C -C +C 

FP125076sp 

MAD617 

ME76 

MD505 

1320 

TAlA 

MD256 

ME509 

OPSAL860 1 

MAD5096- 15 

MAD539s 

TP356b 

l0 = no dye released. 

1 = very slight color visible 

2 = slight color visible. 

3 = moderate color visible. 

4 = deep color visible. 

2-~ = no cellobiose in medium. 

+C = 0.1 pct cellobiose in medium. 

LITERAm CITED 

American Society for Testing and Materials. 

Standard method for accelerated laboratory 

test of natural decay resistance of wood. ASTM 

Stand. Desig. D 2017. Philadelphia, PA; 1971. 

Anagnostakis, S. L. Biological control of 

chestnut blight. Science 215:466-471; 1982. 

Castanho, B.; Butler, E. E. Rhizoctonia decline: 

A degenerative disease of Rhizoctonia solani. 

Phytopathology 68:1505-1510; 1978. 

Castanho, B.; Butler, E. E.; Shepherd, R. S. 

The association of double-stranded RNA with 

Rhizoctonia decline. Phytopathology 68: 

1515-1519; 1978. 

Day, P. R.; Dodds, J. A. Viruses of plant 

pathogenic fungi. In: Lemke, P. A., ed. 

Viruses and Plasmids of Fungi. Marcel Dekker, 

Inc., New York; 1979. 

Esser, K.; Kuck, V.; Stahl, U.; Tudzynski, P. 

Senescence in Podospora anserina and its 

implication for genetic engineering. In: 

Jennings, D. H.; Rayner, A.D.M., eds. 

The Ecology and Physiology of the Fungal 

Mycelium. Cambridge University Press, New 

York; 1984:343-352. 

Esser, K.; Tudzynski, P. Genetic control and 

expression in Podospora anserina. In: 

Lemke, P. A., ed. Viruses and Plasmids in 

Fungi. Marcel Dekker, Inc., New York; 1979: 

595-615. 

Kamar, S. A.; Fulbright, D. W.; Adams, G. C. 

A degenerative disease of Leucostoma cincta, 

the causal agent of Cytospora canker of 

peach. (Abstract). Phytopathology 76:in press; 

1986. 

Highley, T. L. Influence of carbon source on 

cellulase activity of white-rot and brown-rot 

fungi. Wood Fiber 5:50-58; 1973. 
Highley, T. L. Hemicellulases of white- and 

brown-rot fungi in relation to host 

preferences. Material und Organismen 11:33-46; 

1977 .. 

Highley, T. L. Is extracellular hydrogen 

peroxide involved in cellulose degradation 

by brom-rot fungi? Material und Organismen 

17:205-214; 1982. 

Highley, T. L. Measurements of cellulase activity 

in brown- and white-rot fungi on dyed 

cellulose. Material und Organismen 18:161-170; 

1983. 

Highley, T. L.; Kirk, T. K. Mechanisms of wood 

decay and the unique features of heartrots. 

Phytopathology 69:1151-1157; 1979. 

Highley, T. L.; Murmanis, L, L. Determination of 

hydrogen peroxide production in Coriolus 

versicolor and Poria placenta during wood 

degradation. Material und Organismen 20: 

241-252 ; 1985. 

Highley, T. L.; Wolter, K. E. Properties of a 

carbohydrate-degrading enzyme complex from 

the brown-rot fungus Poria placenta. Material 

und Organismen 17:127-134; 1982. 

Ishihara, M.; Shimizu, K. Hemicellulases of 

brown rotting fungus Tyromyces palustris. 

IV. Purification and some properties of an 

extracellular mannanase, Mokuzai Gakkaishi 

26:811-818; 1980. 

Ishihara, M.; Shimizu, K. Purification and 

properties of two extracellular endo-cellulases 

from the brown rotting fungus Tyromyces 

palustris. Mokuzai Gakkaishi 30:79-87; 1984. 

Ishihara, M.; Shimizu, K.; Ishihara, T. Hemicellulases of the brown rotting fungus, 

Tyromyces palustris. 111. Partial purification 

and mode of action of an extracellular 

xylanase. Mokuzai Gakkaishi 24:108-115; 1978. 

Kirk, T. K.; Cowling, E. B. Biological decornposition of solid wood. In: Rowell, R. M., 

ed. The Chemistry of Solid Wood. Advances in 

Chemistry Series 207. American Chemical Soc., 

Washington, DC; 1984:455-487. 

Kirk, T. K.; Highley, T. L. Quantitative changes 

in structural components of conifer woods 

during decay by white- and brown-rot fungi. 

Phytopathology 63:1338-1342; 1973. 

Koenigs, J. W. Production of extracellular 

hydrogen peroxide and peroxidase by woodrotting fungi. Phytopathology 62:100-110; 

1972. 

Koenigs, J. W. Hydrogen peroxide and iron: A 

proposed system for decomposition of wood by 

brown-rot Basidiomycetes. Wood Fiber 6:66-79; 

1974a. 

Koenigs, J. W. Production of hydrogen 

peroxide by wood-decaying fungi in wood and 

its correlation with weight loss, depolymerization, and pH changes. Archive fuer 

Mikrobiologie 99:129-145; 1974b. 

Lemke, P. A. Fungal viruses and agriculture. 

In: Romberger, J. A., ed. Virology in 

Agriculture. Allanheld, Osmun and Co., 

Montclair, NJ.; 1977. 

Lowry, 0. H.; Rosebrough, N. J.; Farr, A. L.; 

Randall, R. 3. Protein measurements with the 

folin phenol reagent. Journal of Biological 

Chemistry 193:265-275; 1951. 

Nelson, N. A photometric adaptation of the 

Somogyi method for determination of glucose. 

Journal of Biological Chemistry 153:375-380; 

1944. 

Wilson, J. F.; Hanton, W. K. Bacteria-like 

structures in fungi. In: Lemke, P. A*, ed. 

Viruses and Plasmids in Fungi. Marcel Dekker, 

Inc., New York; 1979:525-527. 
A Consideration of Factors Affecting the 

Development and Physiology of TissueCul tured 

plants' 

Hazel Y. b?etzstein2 

The applications of tissue culture are 

numerous and include rapid clonal propagation, the production of disease free p1an:s. 

isolation of genetically unique lines, 

germplasm storage, chemical screening, and 

plant breeding applications. The number cf 

in vitro culture protocols for tree species 

is increasing. Yet, protocols with efficiencies suitable for commercial productlor! 

are much less frequent, and are commonly 

restricted to horticulturally oriented 

ornamental and fruit tree species. The 

advent of biotechnological procedures has 

the potential of accelerating tree improvement through methods such as genetic 

engineering, somatic hybridization and 

somaclonal screening. However, the future 

prospects for the clonal production of manv 

hardwood species, except as a research tool 

are limited by economics (Sommer and 

Wetzstein 1984). Particularly for forest 

tree species, the current high costs 

associated with tissue culture production 

greatly limit its application for mass 

propagation. 

Attempts at increasing the efficiency of 

tissue culture systems are most often approached through the optimization of media 

components. Protocol development is often 

centered around regeneration or multiplication rates, with little consideration given 

towards evaluating plantlet form and 

structure. 

'presented as an invited paper at the 

Symposium on Current Topics in Forest 

Research. 

2~ssistant Professor, Department of Houci - culture and Adjunct Assistant Professor, 

School of Forest Resources, University of 

Georgia, Athens, GA 30602. 

Abstract.--In the development of tissue 

culture protocols, it is suggested that in 

addition to regeneration rates, consideration be given to plantlet structure and 

form. Tissue-cultured plants have been 

described to have an atypical anatomy and 

physiology. The modification of the culture 

environment (e.g., light, medium matrix, gas 

environment) may be a means of increasing 

the efficiency of culture systems and of 

producing more competent plants. Some 

results of studies using 

are described 

Plants developed in culture often exhibit 

unusual anatomical and physiological 

features which may contribute to survival 

difficulty after transfer to greenhouse or 

field conditions (Wetzstein and Somer 1982: 

1983) and to early depressed field performance (Frampton and Isik 1986). These 

characteristics include altered leaf 

anatomy, poor vascular development, root 

system abnormalities and depressed photosynthesis. 

Many of these tendencies are a result of 

the peculiar conditions associated with 

culture systems, some of which may potentially be modified to elicit more "normal" 

plant development. Developmental aspects 

should be an important consideration in 

tissue culture methods. For this reason, we 

have been studying environmental and media 

factors and their role on plantlet development at the University of Georgia. The 

rationale has been to understand how 

specific factors affect plantlet development, toward the modification of these 

factors to produce more competent plantlets 

with greater efficiency. 

PLANTS REGENERATED IN CULTURE 

Plantlets developed in culture have been 

described to have an atypical form. We have 

been interested in the tissue culture of 

sweetgum, Lisuidambar L., an 

important hardwood species in the Southeastern U.S. Initial evaluations of regenerated plantlets originated in an attempt to 

explain the stress and desiccation exhibited 

by cultured plants upon transfer to ex vitro 

conditions (Wetzstein and Somer 1982; 

1983). Stress and mortality of cultured 

plantlets appears to be due, in part, to 

water deficits as a result of reduced 

cuticle and wax development, increased 

stomatal densities, nonfunctional stomata, 

and extensive intercellular and substornatal 
air spaces. Similar observations have been 

described in other plants regenerated ic 

culture ( e.g., Brainerd et al 1381; 

Donnelly and Vidaver L884a; Grout and kston 

1978). 

Environment has been shown to haa~e a 

pronounced effect on plant morphology zed 

physiology (Esau 1965; Fitter and Hay 1981) 

The evaluation and manipulation of conditions in vitro hold promise for inpro-ied 

developmental patterns. 

FACTORS AFFECTING DEVELOPMENT 

Enviromental and substrzte effects can 

influence growth and development of plarts 

in culture. Some of these factors can 

potentially be manipulated. This 

paper will describe conditions which we ka-~e 

been evaluating using as a 

model. These inelude Light effects, medicrn 

matrix, and gas environment factors. 

Plants in culture are usually placed under 

low light conditions. A carbohydrate source 

is present in the medium of most culture 

systems, thus high bight for extensive 

photosynthesis may not be necessary in a 

heterotrophie situation. However, the lack of 

a functional autotrophie system may be a major 

problem in transplant v~lnerahility ~jbec 

grantlets are taken from culture to field. 

Low photosynthetic rates have been rneasurcu 

in some culture systems (e.g., DonnelLy and 

Vidaver 1384b; Smith, Palta and McCown 1986\ 

However, under our culture conditions for 

lack of photosynthetic capacrty 

is not a limiting characteristic in piantlet 

acclimatization and transplant growth (Lee, 

Wetzstein and Somer 1985). Plantlets 

exhibited higher rates of photosynthesis 

compared to noncultured plants grown under 

similar light conditions (Table I). 

Table 1.--Net photosynthesis of sweetgum 

seedlings and plantlets at Light intensities 

of 315 high), 155 (medim) and 50 (low) 

p~s-l-m- 1 . 

Light 

Intensity Seedlings PLantle ts 

High 6 .& 12. L 

Medim 4.7 13.6 

Low 2.7 11.4 

As in manipulations for the production of 

autoeroghic suspension cultures, it appears 

that plants in culture can he conditioned to 

undergo active photosynthesis. The development of full photosynthetic capacity should 

be a consideration. 

The effect of light on development is also 

an important factor, Light intensity 

effects on leaf anatomy were evaluated in 

sweetgum in an effort to induce a more 

normal Leaf morphology. A comparison was 

made of cultured and noneultured plants at 

different Light levels. Leaves developed 

under higher light Levels were thicker, had 

a more differentiated palisade, fewer 

intercellular spaces, and greater cuticle 

development compared to low Light leaves. 

However, when in vitro and ex vitro leaves 

developed under similar bight levels were 

compared, cultured leaves were generally 

smaller, thinner and had more extensive 

intercellular spaces. 

Stomata1 morphology was Less affected by 

light bevels, but varied greatly between 

cultured versus noncultured plants. A11 

Leaves in vitro had large, open and raised 

stomata (Figure I?. Leaves developed ex 

vitro had small, sunken stomata with 

ellipsoid guard cells (Figure 2). 

Some of the divergent leaf characteristics 

contnmnly described in tissue culture systems 

can be diminished by the rase of higher light 

intensities. Thicker, more differentiated 

Leaves with more developed cuticles form 

under higher light. However, factors other 

than low light are responsible for other 

characteristics such as raised, nonfmetional stomata wieh higher densities. 

Figure 1,--Surface of leaf developed in 

culture. Note raised, open stomata. X 750. 
Figure 2.--Surface of nuncultured leaf grcx.r 

under the same light conditions as Figur. 1 

X 750. 

Medium Matrix 

Culture gro;:th and development can ci. 

influenced by the physical nature bf tne 

medium. A so2ldif ied meoixni is freqt~c~;ti. 

used as a support and to obtain orderi:~, 

oriented growth. In contrast, fastt3i grt;* :Il 

rates have been reported la Liquid or ic - 

agar medium, but tiith vltxescecce symp tol~li 

occurring in some species. 

In a study comparing medium matrix and 

culture growth, we found greater shoot 

growth. root growth, and rooting perc?ntcaE 

in liquid xyersus agar (0.8% Phytager) 

cultures of (Lee, IJetzstei~ aria 

Somer 1986). Shoot-root ratios were 

greater for liquid than agar-grown pianticLs 

(0.75 versus 0.18, respectively). F~rt'rer 

studies are underway to evaluate osmotic ~~16 

matrix potential effects, availability a?<? 

diffusion of nutrients, and cell differentiation differences as a result of medi~irrl 

matrix changes. 

In studies with sweetgum, trends of less 

negative leaf water potential and more 

negative leaf osmotic potential are obsi-1.r-iei: 

in liquid versus agar medium cultures o-~er 

time, Turgor pressure is greater in Liquld 

versus agar leaves. The processes of eel1 

growth and enlargement are extreme1 jr sens l tr-,-e 

to water deficit conditions. Water potenti-zl 

and specifically turgor presmre ray he 

directly affecting cellular expa-& nsion and 

division, Differences in the degree of 

cortical and vascular tissue development 

ofsweetgm shoots are also observed in 

Liquid versus agar cultures. More extensive 

cell division is exhibited in liquid versus 

agar cultures. 

Plantlet nutrient uptake appears to be 

facilitated in liquid versus agar culture 

medium in our sweetgum system. Significantly higher levels of some nutrients on a 

per plantlet basis were observed in plants 

on liquid medium. Agar has been shown to 

have a restrictive effect on the diffusion 

of some mobecules (Patil, Adhyapak and Joshi 

1985). Uptake differences may also be a 

reflection of root developmental differences. Roots initiated on liquid medium 

were more numerous, of larger diameter and 

with more lateral branching and root hair 

development compared to agar medium cultures. 

Gas Environment 

The gas environment within the culture 

vessel can affect plant development in 

vitra, yet is given relatively little 

consideration in culture protocol development. A variety of vessels and enclosure 

types is zvailable with varying permeability 

values to water vapor and other gases. 

A lack of adequate gas exchange could lead 

to variations in CO2, 02, ethylene, acetaldehyde and other compounds at accumulation 

or deficit levels. For example, ethylene 

has been shown to accumulate in culture 

systems (e.g. Garinlertvatana et al. 1982; 

LaRue and Gamborg 1971). Also of question, 

is if C02 levels in culture are adequate for 

photosynthesis. Container size has been 

shown to influence growth and morphogenesis 

in culture. This effect may, in fact, be t 

due to gaseous environment modification. 

We found that Licjuidambar cultures are 

capable of high rates of photosynthesis 

(Lee, Wetzstein and Sommer 1985). Yet in 

culture, plantlets displayed comparably 

lower growth vigor than noncultured plants. 

It is possible that restricted gas exchange 

(i.e., ethylene accumulation or limiting 

(202) may be a factor. An area of current 

study is the evaluation of different film 

enclosures on gas permeability, and plant 

growth and morphogenesis. Information such 

3s this may contribute to the attainment Of 

full photosynthetic potential and more 

rapid, efficient growth in culture. 
LITERATURE CITED 

Brainerd, K. E.; Fuchigami, L. H. ; 

Kwiatfcrowski , S . ; Clark, C . S . Leaf ar,atoi;ly 

and water stress of aseptically culturea 

' Pixy' plum grown under different eny:iro;~- 

ments. HortScience 16:173-175; 1981. 

Donnelly, D, J.; Vidaver, W. E. Leaf 

anatomy of red raspberry transferred froill 

culture to soil. Journal American Sociecy 

Horticultural Science 109(2):172-176: 

1984a. 

Donnelly, D. J.; Vidaver, W. E. Pigment 

content and gas exchange of red raspberr-7 

in vitro and ex vitro. Journal Arnericz~ 

Society Horticultural Science 109(2):17;- 

181; 1984b. 

Esau, Katherine. Plant anatomy. New York 

John Wiley & Sons, Inc.; 1965. 767 pp. 

Fitter, A. H.; Hay, R. K. M. Environmental 

Physiology of Plants. London: Academic 

Press; 1981. 355 pp. 

Frampton, Lewis John Jr. ; Isik, Kani. 

Comparison of field growth among loblolly 

pine seedlings and three plants types 

produced in vitro. In: TAPPI Proceedings 

1986 Research and Development Conference, 

I986 September, Raleigh, NC; 1986:145-150. 

Gavinlertvatana, P.; Read, Paul E.; Rilkins, 

H. F.; Heins, R. Ethylene levels in flask 

atmospheres of Dahlia pinnata Cav. leaf 

segments and callus cultured in vitro. 

Journal America Society Horticultural 

Science 107:3-6; 1982. 

Grout, B. W. W.; Aston, M. J. Modified leaf 

anatomy of cauliflower plantlets 

regenerated from meristem culture. Annals 

of Botany 42:993-995; 1978. 

LaRue, T. A. G.; Gamborg, 0. L. Ethylene 

production by plant cell cultures. Plant 

Physiology 48:394-398; 1971. 

Lee, Hi; Wetzstein, Hazel; Sommer, Harry E. 

Effects of quantum flux density on photosynthesis and chloroplast ultrastructure 

in tissue-cultured plantlets and seedlings 

of Liauidambar styraciflua L. towards 

improved acclimatization and field 

survival. Plant Physiology 783637-641; 

1985. 

Lee, Ni; Wetzstein, Hazel U.; Sommer, Earry 

E. The effect of agar vs. liquid rnediiliii 

on rooting in tissue-cultured sweetgum. 

HortScience 21(2):317-318; 1986. 

Patil, S. F.; Adhyapak, N. G.; Joshi, S. S. 

Gel hydration: obstruction effect in selfdiffusion. Journal Radioanalytical 

Nuclear Chemistry, Letters 94:121-128; 

1985. 

Smith, Mary Ann Lila; Palta, Jiwan P.; 

McCown, Brent H. Comparative anatomy and 

physiology of microcultured, seedling, and 

greenhouse-grown Asian white birch. 

Journal American Society Horticultural 

Society 111(3):437-442; 1986. 

So~mer, Harry E.; iu'etzstein, Hazel Y. 

Hardwoods. In: Ammirato, P. V., Evans, D. 

A., Sharp, W. R. Vamada, Y., eds. Handbook 

of Plant Gel1 Cultures, Vol. 3. New York: 

Maemillan Pub. Co.; 1984:511-540. 

Wetzstein, Hazel V.; Sommer, Harry E. Leaf 

anatomy of tissue cultured 

styraciflua during acclimatization. 

Journal American Society Horticultural 

Science 108(3):475-580; 1983. 

Metzstein, Hazel Y.; Sommer, Harry E. 

Scanning electron microscopy of in vitro 

cultured Liquidambar (Hamame - 

lidaceae) during acclimatization. 

American Journal of Botany 69:1579-1586; 

1982. 
An Exceptional Case of Natural Regeneration 

of White Spruce in Interior ~laskal 

Tricia L. Wurtz and John C. zasada2 

Abstract.--Traditionally, successful natural 

regeneration of white spruce (Picea glauca 

Moench Voss) requires a mineral soil seedbed for 

germination and establishment. Such a seedbed is 

usually provided in managed systems by scarification. This study suggests that if a large seed 

crop is imminent, and if the dimensions of the 

harvested area are small, scarification may not 

be necessary for sufficient stocking. In such a 

case, scarification may result in such dense 

stands that it is detrimental to seedling growth. 

The distribution of the boreal forest is circumpolar, ranging between the latitudes of 50 

and 68 degrees north. In North Aimerica, the 

most economically important boreal species is 

white spruce (Picea glauca Moench Voss); it is 

the cornerstone of the forest products industry 

in western Canada. In Alaska, it is estimated 

that there are 12.8 million acres (4.8 million 

ha) of commercial white spruce forest land 

(Butchison 1968). The most significant exploitation of Alaska's forests occurred during the 

gold rush period at the turn of the century, 

when large quantities of white spruce were used 

for a variety of purposes. Since then, white 

spruce has been harvested in interior Alaska 

mostly for local use, with small quantities 

exported to Pacific Rim countries. 

Based on research and operational experience 

in Canada, white spruce is a difficult species 

to regenerate (see Zasada and Gregory 1969, and 

Dobbs 1972 for reviews). Attempts at natural 

regeneration have often been particularily unsuccessful, in part because good seed crops are 

sporadic and as yet, unpredictable, The vast 

majority of Canadian studies have found that a 

mineral soil seedbed provides the best conditions 

for seed germination and early seedling development. Such a seedbed is usually provided by 

removing the surface organic layer by mechanical 

means, fire, or a combination of the two, 

While a mineral soil seedbed is ideal for the 

establishment of white spruce, it is also well 

suited to the regeneration by seed of spruce's 

woody competitors (mainly Betula papyrifera 

Marsh and Alnus spp. in Alaskaj. Moreover, 

these hardwood species exhibit a period of 

rapid juvenile growth, which allows them a head 

start over the slow-growing spruce, 

'Presented at the symposium Current Topics in 

Forest Research, Emphasis on Contributions by 

Women Scientists, Nov. 4 - 6, 1986, Gainesville, 

FL 

'~raduate Teaching Fellow, Department a£ 

Biology, University of Oregon, Eugene, OR; and 

Research Silviculturist, U.S. Department of 

Agriculture, Forest Service, Pacific Northwest 

Research Station, Corvallis, OR 

METHODS 

This study was begun in 1971, and was conducted 

at Bonanza Creek Experimental Forest, about 25 km 

southwest of Fairbanks, AK (65"N,148"W). In the 

Fairbanks area, in 1985, there were 107 frostfree days (May 21 - September 5). The mean annual 

temperature was 28°F (-2.2"C), and the total 

annual precipitation was 12.9 inches (33 cm) 

(NOAA 1985). The site was a 160 to 180 year-old 

white spruce stand on a gentle southwest-facing 

slope. The experiment consisted of three clearcut units of 2.5 - 3.8 acres (1.0 - 1.5 ha) each, 

and three shelterwood units of 5.7 acres (2.3 ha) 

each, each with a residual stand of about 33 

trees per acre (80 treeslha). The residual stand 

accounted for 35 - 45 square feet of basal area 

per acre, out of the 80 - 120 square feet per acre 

of the original stand. The units were roughly 

square in shape. The harvesting was done in 

August and September of 1972. Eleven thousand 

board feet per acre was removed from the shelterwoods, and 17,000 board feet per acre was removed 

from the clearcuts. 

The site was scarified immediately following 

logging using a tractor and standard straightedged blade. Scarification was done in 6 foot 

(1.8 m) wide strips, paralleling the contour of 

the hillside. Within the strips, 6- to 10-footlong (1.8- to 3-meter-long) scarified patches 

alternated with unscarified patches. During the 

month that scarification was completed and in the 

following months, a large seed crop fell, measured 

in an undisturbed stand nearby at 500 filled seeds 

per square meter. 

The next spring, forty square-meter plots were 

established in each of the six units, twenty on 

scarified surfaces and twenty on unscarified surfaces. These plots were surveyed after the first 

five growing seasons, and again after the thirteenth growing season, in 1985. In spring, 1986, 

fifteen 1 milacre (4 square-meter) plots were 

established in the dense stands that now occupy 

surfaces that were scarified in 1972. Ten dominant spruce seedlings were selected in each plot, 

and all other woody vegetation was cut at the 

ground and removed. The basal diameters of the 

seedlings in the cleaned and thinned plots were 

measured at the beginning and the end of the 1986 

growing season. Seedlings growing in fifteen 

unthinned control plots were also measured. 
A two-way analysis of variance was done on the 

seedling density data, while the first season 

thinning study results were subjected to a oneway anova (Sokal and Rohlf 1981). 

RESULTS 

Based on the survey conducted in 1985, thirteen 

years after harvesting, no difference was found 

between clearcut and shelterwood silvicultural 

systems in the density of spruce stems per square 

meter. However, there was a highly significant 

difference (p < 0.001) between scarified and unscarified surfaces. No interaction between silvicultural treatment and scarification treatment 

was observed. These results were not only true 

for spruce densities, but also for birch and alder 

densities (Table I). 

Table 1.--Number of seedlings per square meter by 

treatment type, 1985 survey (Mean f 1 sE, n = 60) 

Treatment Spruce Birch Alder 

Scarified 

Clearcut 35.2 (2.15) 28.1 (2.29) 2.5 (0.72) 

Shelterwood 35.8 (2.03) 29.9 (2.09) 3.6 (0.53) 

Unscarified 

Shelterwood 2.9 (0.60) 0.7 (0.25) 0.0 (0.02) 

Spruce, birch and alder frequencies are shown in 

table 2. Frequency is defined as the percent of 

square-meter plots with at least one seedling of 

a given species. 

Table 2.--Percent frequency of seedlings in squaremeter plots (n = 60 per treatment) 

Treatment Spruce Birch Alder 

Scarified 

Clearcut 100 

Shelterwood 98 

Unscarified 

Clearcut 68 3 2 5 

Shelterwood 6 3 19 3 

seedlings growing in unthinned control areas: 

control thinned 

Diameter growth (mm) 

in3units (Mean+ 0.90 (0.10) 1.89 (0.12) 

1 SE, n - 50 for 0.72 (0.06; 1.41 (0.12) 

each value) 0.67 (0-08) 1.00 (0.09) 

Scarification significantly increased white 

spruce seedling density and frequency.in this 

study. An unexpected result was that spruce establishment was good even on unscarified surfaces. 

If 60 percent milacre stocking is the criterion 

for acceptable stocking, stands on both scarified 

and unscarified surfaces were more than sufficiently stocked. This is most likely due to the combination of two factors: the small dimensions of 

the harvested units, and the large seedcrop that 

fell in the months after scarification was complete. One way to look at the importance of small 

harvesting unit dimensions is to consider the number of seeds required by each seedbed type to produce one established seedling. A mineral soil 

seedbed may need only 5 or 10 seeds per established 

seedling, while a seedbed on unscarified forest 

floor may require 100 or even 1000 seeds to produce 

a single established seedling. To maximize the 

chance that unscarified surfaces throughout the 

entire cutting unit receive enough seed, units 

should be laid out so that no point is more than 

200 to 300 feet (60 - 90 m) from a seed source. 

It has been recommended that clearcuts be no more 

than 400 feet (120 m) wide if natural regeneration 

is to be relied upon (Zasada 1972). 

Seed regeneration of the competing species, birch 

and alder, is also favored by the same cultural 

pracrices associated with the successful regeneration of white spruce. In this case, scarification 

improved conditions for birch establishment even 

more than it did for spruce. Scarification increased spruce frequency by 50 percent, while it 

led birch frequency to increase by 300 percent in 

clearcuts and by 500 percent in shelterwoods. 

Other scarification methods, such as removing only 

part of the organic layer, or tilling the substrate 

to make a seedbed of mixed organic and mineral soil, 

may provide conditions that give spruce seedlings 

the advantage over birch. Various new scarification systems are being tested now in Alaska with 

just that goal in mind. Alternately, one can 

attempt to control the competing species' seed 

source. As yet, this technique has not been tried 

in Alaska. 

This study produced excelllent spruce regenera- The spruce seedlings ranged in height in 1985 tion on both scarified and unscarified surfaces. from 11 to 64 inches (0.3 - 1.6 m) on scarified sur- The scarified areas, though, are severely crowded 

faces, and from 5 to 72 inches (0.13 - 1.8 m) on with a combined spruce and birch density of 60 unscarified surfaces. seedlings per square meter. A low-level management plan would allow the crowded seedlings to The seedlings that were released in the spring self-thin, with the dominant seedlings gradually of 1986 showed significantly more diameter growth establishing themselves as the dominant trees. 

(p < 0.001) in a single growing season than A more intensive management plan would seek to 
ensure that each dominant spruce seedling was 

free to grow. Such a plan might call for cleaning out the competing vegetation and thinning 

the spruce seedlings. The results from the first 

season cleaning and thinning study demonstrate 

that overcrowded spruce seedlings respond rapidly 

to being released. Tho utilization of interior 

Alaska's forests is not yet intensive enough, 

however, to warrant such intermediate treatments 

on a large scale. 

LITEWTURE CITED 

Dobbs, R.C. Regeneration of white and engelmann 

spruce: a literature review with special reference to the British Columbia interior. 

information report BC-X-69, Pacific Forest 

Research Center, Canadian Forestry Service, 

Victoria, British Columbia: 1972. 77 pp. 

National Oceanic and Atmospheric Administration. 

Climatological Data: Annual Summary, Alaska 

1985. National Climatic Data Center, Asheville, 

NC; 71(13);1955. 

Sokal, Robert R.; Rohlf, I?. James. Biometry. New 

York: W.H. Freeman and Co.; 1981. 859 pp. 

Zasada, John C. Guidelines for obtaining natural 

regeneration of white spruce in Alaska. U.S. 

Department of Agriculture, Forest Service, 

Pacific Northwest Research Station; 1972. 

Zasada, John C.; Gregory, Robert A. Regeneration 

of white spruce with reference to interior 

Alaska: a literature review. Res. Pap. PNW-79. 

Portland, OR; U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research 

Station; 1969. 37 pp. 

Hutchison, 0. Keith. Alaska's forest resource. 

Res. Bull. PNW-19. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific 

Northwest Research Station; 1968. 
A System Approach to Structural Design 

of Roof ~ssemblies' 

Monica McCarthy and Ronald wolfe2 

Comunication between forest researchers and 

wood products researchers is extremely iqortant. 

There are many areas where wood products research 

overlaps forestry research. Conservation of 

resources can be enhanced by more efficient 

design and use of material. The development of 

reconstituted wood products (small pieces of wood 

held together by adhesives) allows for use of 

timber previously considered waste, and permits 

use of smaller diameter trees. Use of hardwoods 

is another area of interest to both foresters and 

forest products researchers. There is a great 

deal of potential for exciting and creative 

research developments, especially when communication across disciplines is encouraged. At the 

Forest Products Laboratory, in the structural 

research area, we are investigating ways to use 

wood more efficiently and innovatively for structural purposes. 

There have been many barriers to using wood in 

highly engineered structures. The main barriers 

have been concern about decay, insect damage, and 

fire resistance. Other barriers include its 

variability and size limitations. The size of a 

piece of lumber has traditionally been limited by 

the height and width of the tree from which it is 

cut. Knots and other irregularities (grain 

orientation, varying growth rates) make the performance of an individual piece of lumber variable, which necessitates conservative approaches 

in design. 

'To be presented at the symposium "Current 

Topics in Forest Research: Emphasis on Contributions by Women Scientists." 

2~eneral Engineer and Research General Engineer, 

respectively, U.S. Department of Agriculture, 

Forest Service, Forest Products Laboratory, 

One Gifford Pinchot Drive, Madison, WI 53705-2398 

Abstract.--Current design procedures for lightframe residential roof assemblies do not encourage the most efficient or innovative use of 

material. These procedures are based on properties of each individual member without concern 

for interactions between mernbers. At the Forest 

Products Laboratory we are developing analytical 

structural models that will eventually lead to 

system oriented design, We tested four fullscale roof assemblies to failure to verify these 

roof assembly models. 

These structural models will be useful to those 

involved in developing design recsmeedations. 

The models will help evaluate the effects of 

factors such as lmber strength and stiffness, 

roof pitch, truss configuration, span, sheathing 

properties, and comector properties on roof 

assembly performance- Significant inrprovements 

in material utilization could result from design 

changes based on this sensitivity analysis, 

Keywords: Structural methods, wood, roof assemblies* 

There are also factors wbich speak in favor of 

wood, It is by its nature a structural material, 

because it must support itself as it grows vertically. It has a high strength to weight ratio 

relative to other materials sucb as steel. It is 

very easy to work with, and in many cases Large 

wood tihers are actually more fire resistant 

than steel. .The development of preservative and 

fire resistant treatments for wood bas reduced 

difficulties with decay, insect damage, and fire 

resistance* 

The development of plpsod, glularn beams, and 

other wood products wbich combine several pieces 

of lunober with the use of adhesives has revolutionized the wood products industry and opened 

the door to seemingly unlimited potential for 

engineered use of timber. Not only are the size 

limitations overcome, but with the dispersion of 

characteristics sucb as knots, the variability 

problem can be greatly reduced. There are areas 

now in the comercial market where engineered 

wood products are or could be coqetitive with 

steel and concrete, 

Even with the perfomaace of single mefnbers 

more reliable and predictable, understanding and 

predicting the performance of full structures 

is another step, As a start in that area, we 

are looking into the gerfomance of light-frame 

residential structures. We, in cooperation with 

others, are developing structural models for 

light-frame residential floors, walls, and roofs. 

The purpose of these models is to iqrove our 

understanding of the gerfomance of these systems 

which will eventually lead to more efficient 

structural design, as well as innovations in 

designs and types of materials used. 

Because wood has been seen as having lhited 

potential for sophisticated engineering design, 

much of present residential wood design is based 
on tradition, The evolution of wood structures 

over the past 200 years has been guided by those 

islgovations which reduce construction labor costs 

rather than those which improve structural efficiency. Roughly 150 years ago, the introduction 

of mass produced steel nails led to the shift 

from heav tirnber, gost, and beam constructian to 

light-frame platform construction. This was a 

major change to construction methods, but not 

necessarily an improvement to structural perfomance, The popular residential building ism 

used today remains the same as it was in the 

early 1880's. More recently, the replacement of 

board sheathing with wood-based panels, and the 

use of light-frame trusses to replace solid-sawn 

luniber rafters and joists (fig. 1) were also changes 

adopted primarily for labor saving puqoses. 

Because there has been a plentiful supply of 

timber a% a relatively bow cost, by coqarison 

to other materials, there has been little need 

to iqrove the material efficiency of wood 

structures, 

 STUD 

(01 RAFTER ROOF ASSEMBLY 

Ib) PREFABRICATED TRUSS WITH METAL PLATES 

Figure 1,--Tpical roof configurations. (a) Rafter 

roof assembly; (b) prefabricated truss with metal 

plates ., 

Current design procedures consider each element 

of a structural assembly to be acting independently. For exaqle, each rafter of a roof 

assembly is elrpected to support an equal share 

of a unifomly distributed load, Little reeognition is given to the possibility that loads 

may be distributed away from a weak member within 

the assembly, In addition, when one considers an 

entire structural system, assembly interactions 

(floor, wall, roof) may also affect load distribution. For example, a limber wall mag create roof 

problems if the roof is allowed to spread apart 

too easily at the ends, 

Because sf its high degree of variability, and 

the assmption that members act independently, 

current design methods assme that each meniber has 

a near minimm strength for its grade, This is aa 

example of the built-in conservatism in current 

design, which also allows for a comfortable 

margin of error. 

Currently accepted design methods discourage 

the development of imsvative systems. If 

someone wants to design an imovative system 

that relies on assembly- interactions to provide 

the safety margins required by current design 

codes, they have the option of building and 

testing the system to demonstrate its load 

capacity. Such tests are prohibitively expensive 

and rarely used for large systems. 

ROOF ASSEmLY mSTS 

le order to learn more about system performance 

and to provide a data base for validation of 

computer models, we built and tested two rafter 

roof assemblies and two trussed roof assemblies 

(fig. 1). Rafter assehfies are an older fom 

of roof construction where ceiling joists (the 

bottom horizontal pieces) are nailed to rafters 

(the top pieces to which plpood roof sheathing 

is attached) at the construction site. Trussed 

roof asselnblies are made from prefabricated 

trusses held together with metal truss plates. 

In this report we will discuss the test results 

of the trussed roof assemblies. 

The two trussed roof assemblies were similar 

except for their pitch--one had a 3/12 pitch 

(3 in. of rise for every 12 in. horizontally) 

and the other had a 6/12 pitch. Each roof 

assembly was built with nine trusses (fig. 2). 

Trusses were fabricated so that some were intentionally made from low stiffness material, some 

Figure 2*--Test setup for roof assably tests. 
from mediurn stiffness material, and some from 

high stiffness material. The purpose of this 

was to exaggerate stiffness variability to evaluate its effect on assembly performance. 

We measured loads, deflections, and sheathing 

nail slips, a total of 96 data values for each 

load increment, as we loaded the trusses to their 

design load. Before assembling the roof, each 

truss was loaded individually outside the 

assembly. This simulates the performance that is 

assumed in current design procedures. Once the 

roof was constructed, trusses were loaded individually in the assembly. This type of load would 

occur in real life when, for example, bundles of 

shingles are piled on the roof or a person is 

walking on the roof. Finally, we loaded all the 

trusses in the assembly simultaneously. This 

simulates a snow load on the roof. 

Figure 3 shows how the trusses deflected at 

design load for the three types of loadings. 

Trusses appeared stiffer when loaded individually 

in the assembly than when they were loaded 

individually outside the assembly. This was due 

to the stiffening effect of the plywood and load 

distribution. Each truss loaded individually in 

the assembly actually carried only 40 to 60 percent of the applied load. The end trusses 

WEST TRUSS NUMBER (STIFFNESS CATEGORY) EAST 

END END 

I(M1 21H) 3(L) 4(M) 5(H) 6(Ll 7(L) 8(MJ ?(Hf 0.000 ' 

0.025 *----- *----*----*----*- *-<NDIVIDUAL TRUSSES - - _ *-.. IN THE SYSTEM ..% 

i L = LOW 

0.200 M = MEDIUM H = HIGH 

Figure 3.--Deflections for the 6/12 roof system at 

33 pounds per square foot design load. 

deflected more because load could only be distributed in one direction (toward the inner 

trusses), and so they carried a higher proportion 

of the applied load. When the full assembly was 

loaded, trusses deflected more than they did when 

loaded individually in the assembly, because all 

trusses were loaded and less load could be 

distributed to adjacent trusses. In both loadings within the assembly, the variability in 

deflections among trusses decreased. This means 

that the more limber trusses carried less load 

than the stiffer trusses. Thus, provided that 

stiffer trusses are also stronger, roof assemblies have some built-in safety valves. 

We also learned that the end wall stiffness is 

very important. This is an indication of interaction between subsystems (how wall performance 

affects roof performance). 

MODEL DEVELOPMENT 

These tests provided useful and interesting 

information, but they were very specific to the 

particular roof assembly design and loading conditions used. In cooperation with the Forintek 

Corp. of Canada we are developing computer models 

that will simulate roof assembly performance. 

Once these models are validated with experimental 

tests they can be used to model many different 

roof assemblies, and to evaluate effects of 

factors such as lumber strength and stiffness, 

roof pitch, truss configuration, span (length), 

sheathing properties (e.g. plywood thickness), 

and connector properties (e.g. nail diameter, 

truss plate area). 

As new materials and designs are developed, an 

initial determination of their viability can be 

made with'a computer model rather than an expensive structural test. For example, structural 

models may facilitate the development of reconstituted structural wood products made from 

hardwoods. 

SUMMARY 

In wood roof systems, interactions exist which 

are not accounted for in current design methods. 

Development of structural models will enable us 

to quantify and learn more about these interactions, thus promoting more knowledgeable and 

efficient design of wood structures as well as 

providing potential for innovative design. 
Strength of Mechanically Fastened 

Wood Connections' 

Marcia patton-~allory~ 

Mechanical fasteners used in wood construction 

are familiar to any person who has ever driven 

a nail to connect two pieces of wood, used 

screws or bolts, or seen the toothed steel plates 

commonly used to connect members of wood trusses. 

Because of our familiarity with these fasteners 

we often take their behavior for granted. 

What is the significance of mechanical fasteners, and why do scientists study their 

behavior? The history of mechanical fasteners 

use in connecting wooden members dates back to 

ancient Egypt and Rome where wood building connectors were iron, copper, or bronze nails. 

Viking ships were built using copper nails. 

Fastening of wood has been indispensable since 

the earliest times of civilization. Even today 

our industrial progress depends upon our ability 

to fasten things together. Like the principle of 

a chain being no stronger than its weakest link, 

an item made of wood is no stronger than the connections holding it together. In fact, it is my 

intention to help you realize that connections in 

wood structures many times do, in fact, limit the 

strength of the structure. 

The concept of fastening wood using mechanical 

fasteners is a simple one, however, the behavior 

'TO be presented at Current Topics in 

Forest Research Emphasis on Contributions 

by Women Scientists. 

2Research Engineer, Engineering Design 

Criteria, USDA Forest Products Laboratory, 

One Gifford Pinchot Drive, Madison, 

WI 53705-2398. 

Abstract.--Some of the most highly stressed areas 

of a wood structure are in the vicinity of 

mechanical fasteners. Consequently, the majority 

of structural failures initiate at the fastener 

or in the connection areas. The focus of the 

ongoing, and most recently completed, research at 

the USDA Forest Products Laboratory in the 

Engineering Design Criteria Research Work Unit 

is to understand the strength of mechanically 

fastened wood connections. The analysis methods 

used included a European based "Yield Theory" 

which describes mechanisms of failure for bolts, 

nails, and lag screws considering fastener yield 

strength, wood crushing strength, and connection 

geometry. Additionally, fracture mechanics 

analyses are being used to predict connection 

failures where crack propagation is the primary 

mode of failure. This analysis is used where 

fastener end-distances and spacing control connection strength. The results of this research 

are used as a basis for wood connection design 

criteria, published by the National Forest 

Products Association, which are subsequently 

incorporated in the Uniform Building Code and 

local building codes. 

Keywords: Wood connection, mechanical fastener, 

nail, bolt, design criteria, wood joint, timber 

construction. 

of the fastener in a wood connection is extremely 

complex. Despite this complex behavior, simplified design guidelines exist for designing wood 

connections utilizing mechanical fasteners. The 

current design information is based on laboratory 

tests of ideal comections. For the most part, 

wood connection performance has been satisfactory. 

However, according to forensic engineers who 

investigate failure of wood buildings, over 

90 percent of failures occur in the vicinity of 

the connections. I 

WHY DO WOOD CONNECTIONS FAIL? 

There are many reasons why the connection has 

a higher failure rate. First, the connection is 

an area of high stresses. When most mechanical 

fasteners are installed, part of the wood member 

is removed and the metal fastener transmits load 

by interacting with only a small area of the wood 

cross section. Fasteners which are installed by 

driving, such as nails and truss plates, initiate 

small splits in the wood which also create areas 

of stress concentration. 

Second, tensile strength of wood in the direction perpendicular to the grain severely limit 

the strength of many comections. The detailing 

of connections during design and installation can 

have significant strength-reducing implications. 

Finally, but not least important, is the lack 

of basic understanding of how the large number 

of in-service factors interact to increase the 

nominal connection stresses. For example, 

shrinkage perpendicular to the grain in multiple 

fastener connections can cause shrinkage stresses 
which result in conrrmection failure at loads well 

below the design load. Slight eccentricities 

in a group of fasteners can cause the connection 

to perfom as a semi-rigid connection (a connection that transmits moment) which can cause 

stresses perpendicular to the grain to exceed 

perpendicular-to-grain strength, failing 

the connection. Connection spacing and end 

distance requirements assme that sound wood 

exists near the end of the member, However, 

in-service dqing can cause significant end 

splits to develop. Also, wood contains numerous 

knots and other naturally occurring defects which 

are also areas of high stress. The probability 

of these factors occurring simultaneously, and 

their synergistic effects are important real life 

design concerns. 

WWlT IS THE FOCUS OF FPL RESEARCH ON 

CONNECTING WOOD? 

Research relating to comecting wood is primarily spread among three research work units 

(RWfs). These are (I) Engineering Design 

Criteria, (2) Engineered Wood Products and 

Structures, and (3) Intproved Adhesive Systems. 

The majority of the mechanical fastener research 

in the Engineering Design Criteria RW is on the 

comon fasteners: bolts, nails, and lag screws. 

The Engioeered Wood Products and Structures RW 

conducts a Limited amount of research on behavior 

of truss plated connections. Their research on 

truss plated connections is usually limited to 

the necessary testing of specific connections for 

input into floor and roof analysis computer programs. Truss plates are proprietary products, 

therefore, their design infomation is supplied 

by the plate manufacturers. 

Timber connectors such as split rings and shear 

plates are used in some timber structures. 

However, there has been less demand for information on these types of wood connectors compared 

to information on design criteria for the comon 

fasteners. 

Wood joinery was used comonly in early wood 

construction, but is seen most comonly now in 

furniture. These connections include the mortise 

and tenon, dove-tail, and finger joint. Only the 

finger joint has been studied as an engineered 

wood connection during recent times at FPL. 

The Improved Adhesives Systems RW conducts 

research on performance of adhesive connections, 

and with the Engineering Design Criteria RW, has 

conducted isolated studies combining adhesives 

with mechanical fasteners. 

WT INFOWTION IS NECESSARY TO DESIGN 

A WOOD COmCTION? 

There are three levels of complexity in 

designing an adequate wood connection. The three 

research work units at FPL which are involved in 

Wood Engineering Research have vital and distinct 

roles in understanding connection perfomance. 

On the most basic level are the material properties which ultimately limit the connection 

capacity, Basic material properties and factors 

which affect these properties are primarily the 

responsibility of the Engineered Properties of 

Wood RWU. As mentioned earlier, low tension 

perpendicular-to-the-grain strength is a major 

rnaterial property limiting connection performance. Wood compression strength parallel and 

perpendicular to the grain significantly affect 

connection strength and stiffness behavior. 

A second level of complexity exists by considering the way the fastener transfers loads 

between members of the connection. Geometric 

variables include spacing, end distance, bolt 

bearing area, size and alignment of bolt holes, 

and the relationship between loading stresses and 

grain orientation. Engineering Design Criteria 

RWU considers these variables by considering the 

connection as a single entity. How does a bolt 

fail? How do the stresses in the vicinity of the 

fastener hole combine to cause failure? What 

kinds of deformations can be expected from a 

typical connection type in different species of 

wood? How much do connections creep under load, 

and is the "load durationt' effect the same for 

connections as is used for solid wood members? 

Fmen small flaws exist in the vicinity of a 

mechanical fastener, at what stress does the flaw 

grow to a significant crack causing fracture of 

the wood and failure of the connection? These 

are the questions we seek to answer. 

There is a third level of complexity which 

considers thei connection as one type of member 

in a structure made of many types of members. 

Research in the Engineered Wood Products and 

Structures RWU evaluates the performance of wood 

structures using information about the way each 

part of the structure interacts and performs. 

For the adequate design of a wood structure, the 

connection must transfer loads between members 

and eventually to the foundation. This research 

combines beam, column, sheathing, and connection 

performance to model complete roof, floor, and 

wall systems. 

For example, strength and stiffness of the 

fasteners between sheathing and the wood frame 

of a shear wall are critical to wall performance. 

The consequences of inadequate shear walls are 

critical considerations during earthquakes and 

high winds. As part of my graduate research I 

tested shear wall panels to evaluate shear stiffness and shear strength of the wall as a function 

of sheathing and fastener type. (Patton-Mallory 

and others 1984 and 1985). Subsequently, we 

verified a shear wall stiffness model using 

the same wall test data (Patton-Mallory and 

McCutcheon 1986). The stiffness model can evaluate shear wall performance for walls with two 

different sheathing types, e.g. plywood on the 

exterior and gypsum on the interior surface. The 

results of the shear wall research can be used by 

building code officials and others to evaluate 

sheathing required to achieve acceptable shear 

performance in the walls of a structure. 
THE EUROPEAN "YIELD THIZORY" RESEARCH EFFORT 

The bulk of our current fastening research in 

the Engineering Design Criteria RWU is to 

develop adequate computer models to predict how 

connections deform and fail when loaded. Eventually, we will be able to conduct the majority 

of connection tests using the computer, saving 

laboratory testing for model development and 

verification. 

One research effort is to put all dowel-type 

fasteners on a common analytical basis. The 

European community has been using a "Yield 

Theory" to describe the performance of doweltype connections. In the term dowel-type connection they include nails, bolts and lag screws. 

Briefly, the Yield Theory evaluates fastener 

yield using the yield strength of the metal 

fastener and the bearing strength of the wood. 

Yield strength is the load beyond the linear 

elastic connection performance, and can be considered maximum fastener load for most practical 

purposes. A visiting scientist from Norway, 

Professor Petter Aune, studied the applicability 

of the Yield Theory to typical connections in 

U.S. construction (Aune and Patton-Mallory 

1986a ,b) . 

The Yield Theory explains some of the empirical 

adjustment factors that we currently use for 

connection design. For example, when designing a 

bolted joint with steel side plates, the deformation in the connection occurs primarily in the 

wood main member, and is significantly less than 

the deformation seen in a bolted joint made 

entirely of wood. The Yield Theory predicts a 

25 percent increase in yield load when wood 

bearing is the primary mode of failure. When 

bolt bending is the primary failure mode, a much 

smaller increase is justifiable (Soltis and 

Wilkinson 1986). By using analytical models 

rather than relying on experimental data, we can 

better understand which factors influence connection performance, and properly account for 

these factors in our design criteria. The most 

significant impact from adopting the Yield Theory 

is to bring all similar type fasteners together 

with a common analytical basis. This should 

result in more uniform reliability of connection 

design criteria. 

A second research effort involves using fracture mechanics to predict connection failure 

I due to propagating cracks. In this research I 

evaluate critical end distances and spacing of 

bolted connections. The model is being developed 

cooperatively with Professors Steve Cramer and 

Bob Rowlands at the University of Wisconsin. 

Fracture mechanics is an area of engineering 

analysis that evaluates how small flaws grow to 

critical cracks, and lead to eventual structural 

failure. Applications of fracture mechanics to 

the performance of wood products have existed in 

the literature for many years (Patton-Mallory 

and Cramer 1986), but have not had significant 

effect on how we design wood structures. The 

intent of our cooperative effort is to use 

fracture mechanics principles and wood material 

properties to better understand stress concentrations and failure process in the vicinity of 

mechanical fasteners. 

Complimentary to the spacing and end distance 

research is the need to predict load distribution 

among fasteners in a multiple fastener connection. 

This research also involves developing a computer 

model to describe the distribution of load among 

fasteners in a multiple fastener co~ection as a 

function of material properties and connection 

geometry. Historically, the majority of research 

has been conducted on single fasteners. The 

single fastener data are used to design connections containing multiple fasteners. Simply 

derived modification factors account for multiple 

fastener connection strength being less than the 

sum of individual fastener strengths. However, 

significant fabrication effects exist in multiple 

fastener connections. Most bolt holes are oversized to allow easy installation of bolts, and 

to account for small misalignments. When the 

connection is loaded, the oversized holes cause 

fasteners to come into bearing at different 

loads, resulting in one or two bolts carrying the 

load in a connection designed for 4 bolts. This 

causes the loaded bolts to exceed their design 

load. This phenomenon is thought to be the cause 

of recent building failures which involved large 

wood beams with multiple bolt connections. Our 

future research will investigate ways to minimize 

this problem. 

FROM RESEARCH TO DESIGN CRITERIA 

How does the research we conduct on mechanical 

fasteners find its way into the handbooks and 

building codes which are used by building 

designers? The building designer relies 

primarily on a local building code. Local 

codes rely on wood design information from the 

"National Design Specification for Wood 

Construction" published by the National Forest 

Products Association (NFPA). NFPA uses results 

from research conducted at the Forest Products 

Laboratory, as well as research from universities 

and other sources, to specify design criteria for 

wood connections. 

To summarize, the research on mechanical 

fasteners at the Forest Products Laboratory 

involves the expertise of many people. My 

contributions are primarily in the area of 

spacing and end distance effects, including 

applications of fracture mechanics to predict 

failure, load distribution and strength of 

multiple fastener connections, and applications 

of the European Yield Theory as a common method 

to predict yield loads of all dowel-type 

fasteners. 
LITERATW CITED 

Aune, Petter; Patton-Mallory, Marcia. Lateral 

load-bearing capacity of nailed joints based 

on the yield theory: Theoretical development. 

Res. Pap. FPL 469. U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory; 1986 (a). 

Aune, Petter; Patton-Mallory, Marcia. Lateral 

load-bearing capacity of nailed joints based 

on the yield theory: Experimental verification. 

Res. Pap. FPL 470. U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory; 1986 (b) . 

Patton-Mallory, Marcia; and Cramer, Steven M. 

Fracture mechanics: A tool for predicting wood 

component strength. Submitted for publication 

in the Forest Products Journal; 1986. 

Patton-Mallory, Marcia; Gutkowski, Richard El.; 

Soltis, Lawrence A. Racking performance of 

light-frame walls sheathed on two sides. Res, 

Pap. FPL 448. U.S. Department of Agriculture, 

Forest Service, Forest Products Laboratory; 

1984. 

Patton-Mallory, Marcia; McCutcheon, William J. 

Predicting racking performance of walls 

sheathed on both sides. Submitted for publication in the Forest Products Journal; 1986, 

Patton-Mallory, Marcia; Wolfe, Ronald W,; 

Soltis, Lawrence 8.; Gutkowski, Richard M. 

Light-frame shear wall length and opening 

effects. Journal of Structural Engineering, 

American Society of Civil Engineers, lll(10); 

1985. 

Soltis, Lawrence A.; Wilkinson, Thomas L. Bolted 

Connection Desigu; Manuscript in Progress; 1986. 
Modeling the Effect of Moisture Content 

on the Flexural Properties of 

Dimens ion umber ' 

Carol L. ink^ 

Abstract.--Moisture content of a piece of lumber 

affects its flexural properties. Until recently, 

the only procedures available to adjust flexural 

property values of dimension lumber to some 

comon moisture content were based on data from 

small, clear pieces of wood or mean values of 

small lumber samples. Currently, these procedures adjust property values by a fixed percentage 

regardless of the piece's quality. Given actual 

data from dimension Lumber, this paper discusses 

the modeling of the effect of moisture content en 

flexural properties of southern pine and how one 

might judge the adequacy of a model. Traditional 

models were inappropriate for strength properties. 

Kepords: Analytical models, bending, mechanical 

properties, moisture content, lmber. 

This paper reports on the process of modeling 

flexural properties of dimension lumber as a 

function of moisture content. The modeling 

was done with published data on southern pine 

(McLain and others 1984) and resulted in recommendation of models for use in various situations 

(Green and others 1986). A similar study was done 

on Douglas Fir (Aplin and others 19861, resulting 

in recowendation of models for use with that 

 specie^.^ The recommended models are being combined to produce a procedure which is species 

independent. These moisture content studies 

were initiated for two reasons: 

--Concern about procedures currently used to 

adjust flexural properties for moisture content. 

The current procedure (ASTM D 245, 1986) is based 

on mean properties of small samples of lumber 

(Green 1980) and is independent of lumber quality. 

A procedure accurate over the entire distribution 

and based on larger samples would be preferable. 

In addition, some studies (Gerhards 1968, 1970; 

Hoffmeyer 1978; Madsen 1975, 1980) have indicated that an adjustment factor should be 

dependent upon lumber quality--as was, in fact, the 

case from 1930 to 1964 under the so-called "25 percent rule. '' 

--The need of a reliable adjustment procedure for 

data from the In-Grade program. The In-Grade program is a large-scale lumber-testing program being 

carried out in the United States and Canada. 

'presented at the Spposiuna on "Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists." 

2Mathematical Statistician, U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory, One Gifford Pinchot Drive, Madison, 

WI 53705-2398. 

3~reen and others. Manuscript in preparation, 

Forest Products Laboratory, Hadison, WI. 

Because of the scope of the In-Grade program, 

some of the testing is carried out in the field, 

on lumber which vary in moisture content from 

one piece to another. These data will not be useful 

without a procedure to adjust the flexural property 

values to a comon moisture content. 

The procedures described in this report were 

developed for four properties, using three sizes 

of southern pine lumber in three grades at four 

target moisture contents: 

Grades Sizes 

Select Structural 2 by 4 

No. 2 2 by 6 

No, 3 2 by 8 

Moisture contents Properties 

Green Modulus of rupture 

20 percent Modulus of elasticity 

15 percent Flexural stiffness 

10 percent Moment capacity 

Coefficients for adjustment procedures for all 

properties, sizes, and grades are given in Green 

and others (1986). Further details of the procedures 

used in gathering and drying the lumber are given in 

McLain and others (1984). This gaper is designed to 

cover the modeling process used in developing the 

procedures. For simplicity, the discussion in this 

paper deals only with one property (modulus of 

rupture (NOR)), one grade (Select ~tructural) , and one size (2 by 4). In the overall study 

described in Green and others (1986) for all 

flexural properties, models were first derived 

from data for each of the nine gradelsize 

combinations. Then models were derived from all 

the data sets simultaneously, 

The final section of this paper shows how to 

assess the accuracy of these models, 

4~reen and others. Manuscript in preparation, 

Forest Products Laboratory, Madison, WI. 
THX MODELS 

Several analytical models were tested for their 

ability to predict the effect of moisture content 

on flexural properties : 

(1) A zero adjustment model. 

(2) Constant percentage models. 

(3) Strength ratio models. 

(4) Weibull models. 

(5) Surface models. 

All modeling was based on the assmption that given 

percentiles of the property distributions at one 

moisture content are adjusted to the corresponding percentile of the property distribution at 

another moisture content. Each type of model 

contains a value of moisture content above which 

the flexural properties do not change, known as 

the intersection moisture content, M . TradiP 

tionally this value has been 21 percent for 

southern pine, although Wilson (1932) shows that 

this value varies with property for clear wood. 

Given the models considered in this paper, we 

found no reason to change this value (Green and 

others 1986). 

Zero Adjustment Model 

This is the simplest of all the models; no 

adjustment for moisture content is taken. 

Although not an appropriate model for our purposes, it serves as a baseline against which 

other models can be compared. 

Constant Percentage Models 

Constant percentage models do adjust for moisture 

content, but the adjustment factor is the same, 

regardless of the quality or size of the lumber. 

All current standard adjustment procedures for 

dimension lumber and for clear wood are of this 

type. An example is the model developed by Wilson 

(1932) and given in the Wood Handbook (1974) 

for small clears. This model for longleaf pine is 

shown as the solid line in figure 1. The ASTM 

D 245-81 (1986) adjustment factor for all species of 

lumber is shown as the dashed line. Each of these 

lines starts at 8,500 pounds per square inch 

(1b/ina2), the value given for green (21 percent 

moisture content) longleaf pine in the Wood 

Kandbook. Note that the adjustment for small 

clears is much larger than the adjustment for 

lumber. To adjust a value of 8,500 ~b/in.~ for a 

green piece, i.e. a moisture content of 21 percent, 

to 15 percent, one would follow the plotted lines 

and read off adjusted values of 12,000 lb/in.2 for 

the small clears and 9,500 lb/in.2 for the ASTM 

lumber. 

The form of the constant percent models is 

P2 = FtP where P. is the property value at 1 

moisture content i, i = 1,2, and F is the moisture content adjustment factor. F is a function 

only of the two moisture content levels, MI and 

M2. One could obtain lines to adjust other 

values by using the same constant percent, F, and 

varying the initial property PI. This yields a 

set of fanning lines. One of these sets of lines 

for the ASTM lumber adjustment procedure is shown 

in figure 2. Think of these lines as a set of 

contours. When you wish to adjust a property P 1 

at moisture content M to the corresponding 1 

property at moisture content M2, you need to find 

a contour which intersects the point (M P ), 1' 1 

Following this contour along to M you are then 2 

able to read off the corresponding property value 

at the point (M2,P2). 

To determine the moisture content adjustment 

factor, F, for constant percentage models, one fits 

a regression to all pairs of property value and 

moisture content values (M,P). M and P without 

subscripts denote general pairs of data points. The 

moisture content of the green samples is replaced 

by Mp. Three different types of regression 

models were used: 

Linear P = a + b*M 

Exponential P = exp(a + b*M) 

Quadratic P = a + b*M + c*M 2 

The moisture content adjustment fastor F to 

adjust properties from moisture content M 1 to 

is F = P2/Pl, where P is the value from the i 

equation at M i = 1,2. The linear model will i ' 

give a set of linear contours (like the ASTM 

lumber model), the exponential model will give a 

set of concave contours (like the clear wood 

model), and the quadratic model will yield a set 

of convex contours if the value of c is less than 

zero, which was the case in this study. These 

models fit the average trend of the data. The 

Select Structural 2 by 4 data plus the three 

fitted lines are shown in figure 3. Data points 

with moisture content values larger than 21 percent are plotted at 21 percent, which is the value 

of M . The linear model is shown as the solid 

P 

line, the exponential model as the short dashed 

lines, and the quadratic model is shown as the 

long dashed line. These three lines do not 

differ by much, so they will yield similar 

adjustment procedures. To obtain a model independent of grade and size, one must fit the 

three regression models to all the data, instead 

of just a selected grade and size. 

Strength Ratio Models 

Strength ratio models assume that the moisture 

adjustment factor, F, depends on the strength 

ratio of the lumber. The strength ratio is a 

function of lumber quality. The "25 percent rule'" 

(fig. 4) is such model. The strength ratio of a 

piece of lumber varies from 0 to 100 percent and 

is an estimate of the strength of the piece in 
Moisture content, pct 

Figure 1.--Current moisture content adjustment 

procedures for MOR: solid line = small clears, 

dashed line = lumber. These procedures are 

similar to the constant percentage models used 

in this study. (ML86 5340) 

Moisture content, pct 

Figure 2.--A set of contours for ASTM D 245 

moisture content for MOR of lumber. The 

procedure was a constant percentage model. 

(M.86 5341) 

Yogistwe content, pct 

Figure 3.--Select Structural 2 by 4 MOR data. 

Pieces with moisture contents above 21 percent 

are plotted at 21 percent: solid line = linear 

fit, short dashes = exponential fit, long 

dashes = quadratic fit. These lines are used 

to construct constant percentage models. (ML86 5342) 

Strength ratio, pet 

Figure 4.--Moisture content adjustment factor, 

F (from green to 15 pct): 25 percent rule, 

as a function of strength ratio. This procedure 

is a strength ratio model. (ML86 5343) 
comparison to one with no strength-reducing defects 

such as slope of grain or knots, To be graded as 

Select Structural, No. 2, or No. 3, the strength 

ratio of a piece of lumber must be greater than or 

equal to 65 (67 for 2 by 4s), 45, and 26 percent, respectively. If the strength ratio is 

below some cutoff value, yO, here 50 percent, 

then F = 1, i.e. no adjustment is taken. The 

maximunt adjustment, P, occurs for pieces with 

strength ratio of 100 percent, here Fk = 1.25, i.e. 

a 25 percent increase from green to 15 percent 

moisture content. 

The southern pine data set gives us little 

information from which to choose a form for an 

adjustment factor dependent upon strength ratio, 

because 55 percent of the data had strength ratios 

above 90 percent (even though only approximately 

one-third of the data is Select Structural with 

the other two-thirds being No. 2 or No. 3). 

Therefore we asswed that E had a value equal to 

one below some cutoff, yo, then curvilinear (like 

the 25 pct rule) or linear until it reached a 

value of Fi at 100 percent strength ratio. The 

cutoff values chosen were 0, 26, 45, and 50 percent. The values of 26 and 45 percent correspond 

to the minim- acceptable strength ratio values 

for No. 3 and No. 2 grades of structural lmber, 

respectively, The value of O percent gives a 

nonzero adjustment factor for evesy piece, and the 

50 percent value corresponds to the value used in 

the 25 percent rule. 

Given the assued form of the strength ratio 

models, all that was left to model was fl as a 

function of moisture content. To do this, pieces 

with strength ratios of 100 percent were selected. 

As with the constant percent models, the property 

values were modeled as a function of moisture 

content by using either the linear or exponential 

model. Because grade is assmed not to be a factor 

(having already been taken care of with strength 

ratio), the models of F* were done by size or 

with all the data. As an exanrple, the MOR of the 

2 by 4 data with strength ratios of 100 percent 

are plotted in figure 5 against moisture content 

with the fitted linear (solid line) and exgonential (short dashed line) models, Again either 

the linear or exponential MORlmoisture content 

relationship will give similar moisture content 

adjustment models. A quadratic model could have 

been used, but the results would not differ 

significantly from the exponential or linear 

model. The value of F" going from greea to any 

other moisture content is plotted in figure 6 for 

the exponential model. At 15 percent moisture 

content tbis mean value is 1.23 which compares 

favorably with the value of 1.25 from the 

25 percent rule. To obtain a model independent 

of size, one must fit the models of P, using all 

the pieces with 100 percent strength ratio 

instead of just one size. 

Weibull Models 

This type of model is obtained by first fitting a 

two-parameter Weibull distribution to eaeb of the 

36 gradelsizelmoisture groups. The distributional 

parameters are given in McLaia and others (1984). 

The fitted two-parameter Weibull distribution is 

plotted with the data lor Select Structural 2 by 

4, 20 percent moisture content group in figure 7. 

The two parameters of the Weibull distribution are 

known as the shape and scale parameters. The shape 

and scale parameters were then modeled as a quadratic 

fuaction of moisture content. The shape and scale 

parameters for the Select Structural 2 by 4 data and 

fitted quadratic curves are given in figure 8. Then 

the property value, P2dat moisture content M 2" 

given the property value, PI, at moisture content M 1 

is: 

where a is the estimated scale parameter and b i i 

is the estimated shape parameter at moisture 

content i, i = 1,2. Weibul1 models fit to each 

gradefsize combination contained six coefficients 

each (two parameters, shape and scale, each 

modeled by a quadratic equation which has three 

coefficients). Therefore, there are 54 coefficients when considering a11 the data (9 separate 

gradelsize combinations), Using analysis of 

variance, we were able to reduce tbis amber of 

parameters to 19, but the resulting model is 

still dependent upon grade and size. To use a 

Weibull model for grades and sizes which were 

not tested requires some asslunption of how the 

coefficients vary across grades and sizes. Sizes 

could be modeled using nominal values--3.5, 5.5, 

and 7.25--hut there is no clear americal conversion for grade. 

Surface Models 

A surface model is obtained by fitting a surface 

to the relationship between MOR and moisture 

content. In these models, we atteqted to find 

contours that were similar to how the underlying data 

behaved. For example, a visual s 

Select Structural 2 by 4 data is given in figure 9. 

For each of the four groups of data (target moisture 

contents of 10, 15, 20 pct and green), 21 percentiles 

(2nd, 5th, loth, ..., 90th, 95tb, and 38th) are 

plotted versus the average moisture conteat for that 

group. The green group is plotted at 21 percent 

moisture content. Now if we join like percentiles, 

this forms a target of hat our contours should look 

like with perhaps some smoothing. Some of these 

contours look as if they could be fitted with a 

straight line; others look as if a quadratic equation 

would be necessary. So we fitted linear and 

quadratic surface models, depending on whether the 

fitted contours appear in a linear or a quadratic 

fomat, In tbis paper, only the quadratic surface 

models will be discussed. 

A quadratic model was fitted to each of the 

21 percentile sets, each consisting of 4 pairs 

of points, mentioned above. Next, the coefficients of the quadratic and linear terms were 

plotted versus the predicted MOR values at 

15 percent moisture content using the quadratic 

equations (figs. 10 and 11). Some baseline 

moisture conteat must be chosen, but the choice 
Noidwe content, pct 

Figure 5.--MOR data for 2 by 4's with 108 percent 

strength ratio. Pieces with moisture contents 

above 21 percent are plotted at 21 percent: solid 

line = linear fit, short dashes = exponential fit. 

(ML86 5344) 

Moisture content, pct 

Figure 6.---w, Moisture content adjustment factor 

at 100 percent strength ratio (from green to 

another moisture content. (PIL86 5345) 

NOR, 1000 psi 

Figure 7.--Select Structural 2 by 4 MOR, 20 percent moisture content group: data = solid line, 

fitted two-parameter Weibull distribution = 

dashed line. (ML86 5346) 

Moisture content, pct 

Figure 8.--The Weibull distribution's shape parameter 

(squares) and scale parameter (triangles) data for 

Select Structural MOR with fitted quadratic curves: 

Weibull shape = solid line, scale = dashed line. 

(ML86 5347) 
of 15 percent was arbitrary. Now a cubic function was fitted to these points. Contours using 

these fitted coefficients are shown in figure 12. 

Contours for small values of HOR do not behave 

nicely because there is no Select Structural 

2 by 4 data in this region. Given any property 

value PI at moisture content MI, one needs to find 

a contour that goes through the point N1,PI 

The property value at M2 is then read off of this 

same contour. In practice, these contours start 

behaving badly sear the extremes of MOR. Therefore, 

the contours above and below the data were bounded 

(fig. 13). (The bourrding for higher NOR values would 

be more apparent for lower grades of luuiber because 

for those grades tbere would be ao data in tbat 

region.) The lower contours were not allowed to 

be concave, and the upper contours are parallel to 

the contour going through the predicted PlBOR value at 

15 percent moisture content of 14,000 ~bfin,~ 

(essentially the upper bound of the data). Ts 

fit surface models which are independent of grade 

and size, coefficients were fit to I89 sets sf 

quadratic and linear terns (9 gradelsize combinations each with 21 sets of percentiles) instead 

of just 21 sets for each gradelsize combination. 

ASSESSING Tm MODELS 

If no adjustment for moisture coatent is made, 

the curves of the MOR distributions for the four 

moisture coateats (green, 28, 15, and 10 pct) 

are quite different (fig. 14)- However, if each 

of the four distributions were adjusted by a 

perfect procedure to a comon moisture content, 

the four adjusted distributions would have exactly 

the same curve, The similarity between the curves 

of adjusted distributions would reflect the ability 

of the procedure to model the effect of moisture 

content. 

As mentioned, models were first derived using 

only a single gradefsize codination and then 

using all sine gradelsize combinations. For 

simplicity, this report contains graphs only of 

models derived from Select Structural 2 by 4 data 

(see figs. 15 and 16). These models are then 

coerpared with those derived from all nine grade! 

size groups (see table 1). Men each of the four 

data sets for Select Structural 2 by 4s are adjusted 

to a moisture content of 21 percent (green) using 

the quadratic surface model for Select Structural 

2 by 4s, the cmulative distribution fmctions appear 

to be quite similar (fig. 15). Although the distribution functions are not identical, we did not 

find other models that gave curves tbat were more 

similar. Using the data from Select Structural 

2 by 4s with the quadratic constant percent model 

for Select Structural 2 by 4s yields a set of 

cmulative distribution functions that are slightly 

more discrepant, especially at upper end (fig. 15), 

but much better than no adjustment. Strength ratio 

models were worse than any constant percent models, 

Weibull models worked as well as the quadratic surface 

models but were not independent of grade and size. 

data sets adjusted to the same moisture content, 

Table 1 shows the maxirnm absolute differences in 

MOR at the 5th, 50tb, and 85th percentile between 

the four moisture content groups oh Select 

Structural 2 by 4s when those data were unadjusted 

and when adjusted by two of the types of models coasidered in this study, The absolute differences 

for the two model tmes are shown both for models 

derived only from Select Structural 2 by 4 data and 

for models derived from the data of all nine grade/ 

size groups (models independent of size and grade). 

Similar results are found when adjusting the data to 

another moisture content. 

Table I.--Maximm absolute differences (Lbjin.') 

for Select Structural 2 by 4 adjusted to green 

(21 pct moisture content) 

5th 95th 

Model ger- per- Median cent- centile if e 

No adjustment 2,210 4,150 5,590 

Constant percent, 

quadratic 

Select Structural 

2 by 4 5 38 310 750 

AZI nine gradeisize 648 930 1,370 

Surface, quadratic 

Select Structural 

2 by 4 560 230 450 

All nine gradelsize $90 220 510 

Some Loss in precision occurs when going from an 

individual gradelsize model to an overall model 

which is independent of grade and size. However, 

one would prefer a model independent of grade and 

size, so that data from sizes and grades which 

were not part of this study could be adjusted. A 

model independent of grade and size would not have 

to be changed if grading rules or standard d-jrsneasions changed, Also, models specific to one grade 

and size may overfit some of the peculiarities of 

the given sets of data. This is why one might 

use the quadratic surface model independent of 

grade and size to adjust Lumber property data. 

It adjusts all parts of the property distribuLions almost as well as a nnadel dependent upon 

grade and size. 

Another way to characterize how well a model 

does is to look at the maximm absolute differences at selected percentiles between the four 
Moisture content, pct 

Figure 9,--Select Structural 2 by 4 MOR data, 

selected percentiles (2nd, 5th, loth, ..., 90th, 

95th, 98th) plotted at group average moisture 

content (21 pct for green group). The 2nd, 20th, 

40th, 60th, 80tb, and 98th percentiles are 

represented by Xs. (ML86 5348) 

I 

! 

-1.5 

0 5 10 15 20 

MOR at 15% MC 

Figure 10.--linear coefficients for the surface 

model versus predicted MOR at 15 percent moisture 

content plus fitted cubic equation, (PIL86 5349) 

MOR at 15% MC 

Figure 11.--Quadratic coefficients for the surface 

model versus predicted MOR at 15 percent moisture 

content plus fitted cubic equation. (ML86 5350) 

LITERATWE CITED 

American Society for Testing and Materials. 

Establishing structural grades and related 

allowable properties for grades of structural 

lumber. ASTM D 245-81. Philadelphia, PA: ASTM; 1986. 

Aplin, N.E.; Green, D.W.; Evans, J.W.; 

Barrett, J.D. The influence of moisture content 

on the flexural properties of Douglas Fir 

dimension lumber. Res. Pap. FPL 475. Madison, 

WI: U.S. Department of Agriculture, Forest 

Service, Forest Products Laboratory; 1986. 

Gerhards, C.C. Four-inch southern pine lumber: 

Seasoning factors for modulus of elasticity 

and modulus of rupture. Forest Products Journal. 

18(11):27-35; 1968. 

Gerhards, C.C. Further report on seasoning fac- i 

tors for modulus of elasticity and modulus of I 

rupture. Forest Products Journal, 20(5):40-44; 1970. , 

Green, D.W. Adjusting the static strength of 

lumber for changes in moisture content. In: 

Proceedings, Workshop on how the environment 

affects lumber design: assessments and recommendations. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory; 1980. 

Green, D.W.; Link, C.L.; DeBonis, A.L.; 

McLain, T.E. Predicting the effect of moisture 

content on the flexural properties of southern 

pine dimension lumber. Wood and Fiber Science. 

18(1):134-156; 1986. 
Hoffmeyer, P. Moisture content-strength relationship for spruce lumber subjected to bending, 

compression, and tension along the grain. In: 

Proceedings, IWRO wood engineering group 

meeting, Vancouver, BC; 1978:72-91. 

Madsen, 3. Moisture content-strength relationship 

for lumber subjected to bending. Canadian 

Journal of Civil Engineering. 9:465-473; 1975. 

Madsen, B.; Janzen, W.; Zwaagstra, J. Moisture 

effects in lumber. Structural Research Series 

Rep. No. 27. Vancouver, BC: Deparment of Civil 

Engineering, University of British Columbia; 1980. 

McLain, T.E.; DeBonis, A.L.; Green, D.W; 

Wilson, F.J.; Link, C.L. The influence of 

moisture content on the flexural properties 

of southern pine dimension lumber. Res. 

Pap. FPL 447. Madison, WI: U.S. Department 

of Agriculture, Forest Service, Forest Products 

Laboratory; 1984. 

U.S. Forest Products Laboratory. Wood handbook: 

Wood as an engineering material. Agric. 

Nandb. 72. Madison, WI: U.S. Department of 

Agriculture, Forest Service, Forest Products 

Laboratory; 1974. 

Wilson, T.R.C. Strength-moisture relations for 

wood. Tech. Bull. No. 282. Madison, WI: 

U.S. Department of Agriculture, Forest Service, 

Forest Products Laboratory; 1932. 

Moisture content, pct 

Figure 12.--Umodified quadratic surface model 

contours for Select Structural 2 by 4 NOR. 

(ML86 5351) 

Moisture content, pct 

Figure 13.--Modified quadratic surface model 

contours for Select Structural 2 by 4 MOR: bounded 

moisture content adjustment for small and large 

values of MOR. (ML86 5352) 
MOR, 1000 psi 

Figure 14.--Cwulative distribution functions for 

Select Structural 2 by 4 MOR data with no adjustment 

for moisture content: solid line = green group, 

long dash = 20 percent group, medim dash = 

15 percent group, short dash = 10 percent group. 

(Me85 5353) 

MOR, 1000 psi 

#OR, 1000 psi 

Figure 16.--Cwulative distribtution functions 

for Select Structural 2 by 4 MOR data after 

adjusting data to green (21 pct moisture content) 

by the Select Structural 2 by 4 quadratic constant 

percent model: solid line = green group, long 

dash = 20 percent group, mediw dash = 15 percent 

group, short dash = 10 percent group. (HZ86 5355) 

Figure 15.--Cumulative distribtution functions 

for Select Structural 2 by 4 NOR data after 

adjusting data to green (21 pct moisture content) 

by the Select Structural 2 by 4 quadratic surface 

model: solid line = green grow, long dash = 20 percent group, medium dash = 15 percent group, 

short dash = 10 percent group. (m86 5354) 
THE IMPORTRKCE OF ARCHEOLOGICAL SITES SEZATFD TO THE 

NAVAL STORES INDUSTRY IS FLCK DA~ 

Sandra Jo l?orneY2 

The production of naval stores was the first 

major industry of the southern pine forests. The 

industry extracted resin from pine trees and distilled it to produce rosin, turpentine, pitch, 

tar and other products. Over the past three 

centuries, naval stores have been used in the 

construction of ships, paper sizing, perfumes, 

adhesives, pharmaceutical supplies, plastics and 

paints . 

Like other forest products, the naval stores 

industry provided employment for Blacks leaving 

the plantation system during the Reconstruction 

Era. Archeological investigations in other areas 

of the Southeast have provided glimpses of the 

social and economic nature of the plantation system (Otto 1975, 1977, 1980; Singleton 1980). 

Since the lumber and turpentine industry was 

essentially an extension of the plantation system 

(Shofner 1974, 1981a, 1981b) relationships sinilar 

to those among the plantation owner, the overseer 

and slave or indentured servant and later sharecropper may be expected among the workers of a 

naval stores operation. The following discussion, 

adapted from historical research of primary and 

secondary sources, forms the basis for establishing the potential significance of archeological 

sites related to the naval stores industry in 

Florida . 

Over the years the turpentiners evolved a 

distinct society due to their usual isolation 

(Hickman 1962). During the latter 19th and early 

20th centuries, naval stores was an industry with 

a routine of labor, language and life that was 

distinct and often viewed as picturesque. A 

typical day's work for a turpentiner was from 

"kin to kant" (dawn to dark). He would rise about 

4:30 a.m., eat a quick meal prepared the night 

before, and head into the woods at first light, 

Between 8:00 and 9:00 a.m. the turpentiners ate 

a light meal which also was prepared and packed 

the night before. They worked until nearly sundown, then walked back to their quarters for 

supper and borne chores. This ritual was performed 

five or six days per week denending on hot7 fast 

I~resented at the Symposium on Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists, November 4-6, 1986, Gainesville, 

FL. Co-sponsored by the USDA Forest Service, 

Southeastern Station, and the Univ. of Florida. 

2Forest P,rcheoiogist, National Forests in 

Florida, Tallahassee, FL. 

each got the prescribed job done (Schultz 

1982 : 38). 

As in the planration system, naval stores 

onerations also had an overseer or foreman. This 

individual, who made his rounds on horseback, was 

called a "woodsrider. 'vrdoodsriders were generallj.7 

Caucasian and their duties were to insvect and 

su~ervise the work at a turpentine stand. The 

Black workers \*ere under the co~plete control of 

the x~oodsrider. in fact, it was said that a 

woodsrider, snorting a nistol and .i7hip, was the 

law in those isolated areas. 

The workers usually received company scrig or 

metal tokens as wages. These were only redeemable at the operator's comissary hich was 

usually lacated at the tur?entine distillery. 

Other forms of money could be acquired by trading 

scriv at a discount, however, For most 1-~orkers, 

access to areas outside the turpentine cam? or 

distillery was forbidden. Saturday was generally 

payday at the turpentine camp. Yale workers were 

paid about $10 ner month, while female workers, 

naturally, received $2 less. The etroodsrider, 

however, received around $30 per month, whicb was 

usually naid in currency rather than scrip. 

Goods were usually nurchased on credit from the 

commissary lihose keener affixed a high interest 

charge. Thus, the workers were usually indebted 

to the comvany store, making their ability to 

leave the tur~entine camins for other ennloyment 

even less likely. The commodities supplied by the 

comissary system suggest that most peals of the 

workers nrobably consisted of cornbread, bacon, 

black coffee and an occasional treat of baking 

powder biscuits (Pridgen 1962:150). Berries, 

grapes, persimons, nuts and other edible wild 

plant foods were probably also gathered in season. 

Housing and water were furnished as part of the 

workers' connensation, Because the trees began 

to lose their productivity after several years, 

turpentine camps were occupied tevoorarily, 

usually for a period of five years, Vast of the 

early trees were worked near rivers for easy 

shinnent . Side camns and distilleries, where the 

resin tras processed into turnentine, began moving 

into the interior ?ortions of the forest r~hen 

railroad lines were comqleted in the late 19th 

century. 

?lost turnentine workers lived in shacks or 

quarters grouped closely together or in rows to 

?revent the socZal !-soletion inherent Fn liv?ny 
alone in the mods, and to provide a better nearis 

of overseeing and controlling workers activities, 

These rough lumber shanties, occuoied by both 

workers and the woodsrider, were located at side 

camps and at the distillery, 

Early shanties for the workers were often oneroom pole structures with no floor or windows. 

If a worker's fanily was large, a lean-to was often 

added alang one wall for additional sleeping snace, 

Each shanty occupant or family probably had a 

small garden of vegetables to supplement their 

diet, 

Data compiled during a land acquisition appraisal 

of a Liberty County turpentine camp in the 1930'~~ 

provides an indication of status differrntiation 

in the camp (USDA 1934). In addition to 27 box 

and frame quarters to house 157 occcpants and their 

families, the camp, encompassing 640 acres, included a combination church and school, commissary 

and cemetery. 

The workers' shanties,valued at $10 each, were 

22'x24' wood frame structures with at least two 

rooms. Housing for the foreman, hovever, consisted of a six-room dwelling measuring 22'x40', 

and was valued at $50. The appraised value of the 

stable, shed and garage was equal to that of the 

workers' shanties in the camp, 

With few exceptions, archeological remains from 

occupational areas of the side cam? differ little 

from those of the distillery site, since most 

commodities at both types of sites were ~urchased 

at the company commissary. Glass and ceramic 

remains constitute the majority of the utilitarian 

materials associated with these sites. Kerosene 

lantern gloves and bases, beverage and medicinal 

bottles, and ornate cut glass dinnerware are the 

most common types of glass reflecting life at the 

turpentine site. The greatest percentage of 

utilitarian ceramics collected from these sites 

is ironstone, with other types in lesser frequencies. The material remains associated with 

a turpentine stand include isolated objects such 

as beverage bottles, cups, tools, and other equipment used during the operation of gum collection, 

as well as an occasional domestic item. 

The socio-economic conditions of turpen~ine 

workers remained constant, despite a number of 

technological advances which improved harvesting 

and processing techniques, One of the major 

developments which drastically changed the industry 

was the introduction of the clay collecting cup. 

Initially, the gum or resin was collected in 

"boxes" or collecting basins chopped into cbe 

bases of trees with a broadaxe. A "streak" or 

wedge-shaped groove was then cut into the face of 

the tree above the box to allow gum to flow. Each 

week a new streak was cut to increase this flow. 

The box cavity was found to weaken the tree at the 

base, leaving it vulnerable to disease, wind, and 

fire and to lessen the value of the tree as timber 

for lumber. 

Although the boxing method remined in comn 

use until aSout 1915, Charles Eertyk 1904 

invention of the clay cup, initiated a new method 

for collecting pine resin. A streak was made in 

the tree and then an incision was cut into the face 

where a gutter was fastened to direct the flow of 

resin into tbe collecting cup ~chich hung by a 

single nail belo~a. The use of clay increased the 

quality of resin by avoiding irrparities which 

tended to collect in the oqen box cavity. 

Stylistic changes in turpentine collecting cups 

are a major soorce for determining the chronology 

of a naval stores related site in Florida. Dis- 

~inctions in the nhysicai characteristics of 

collecting cups nay be due to functional, temporal 

or spatial considerations. The relative dates and 

possible ranges for the nmnufacture and use of 

these cups were derived from a number of sources, 

particularly previous research conducted by Salph 

Clerients at the Olustee Forest Experiment Station. 

Turpentine cups now in the ?luseun of Florida 

History collection in Tallahassee beautifully 

illustrate variations in 20th century clay and 

metal cups. Because they were much cheaper to 

purchase than ~etal, clay cups were almost exclusively used in Florida, except in the northern 

part of the state where clay cups could easily 

3reak during a freeze. 

The Herty cun was the most common style on the 

market. Established in 1904, the Herty Turpentine 

Cup Company of Daisy, Tennessee, produced at least 

60,000 cups per day until about 1914, when the 

advent of galvanized iron cups forced a decrease 

in the demand for ceramic cups. These cups were 

qarketed exclusively in Alabama, Georgia and 

Florida (Smith and Rogers 1979). 

Yajor ownership in the Herty Cup Company was 

with the Consolidated Naval Stores Company of 

Jacksonville from 1910 until 1942 when the company 

was voluntarily dissolved. These dates correspond 

nicely with the major era of naval stores production in the State, ~articularly in the 

Jacksonville area. 

Another variety of clay collecting cup was connected to the tree by a metal fastener at the rim 

instead of being hung by a nail. The exact puroose of this unique attachment is not currently 

known. These cuys were probably used in Florida 

between 1910 and 1925. Reminiscent of the Herty 

cup, due to its fluted exterior and similar red 

paste, this cup may also have been made at the 

Tennessee plant. 

The clay Pringle CUD, curved to fit the shape of 

the pine tree, was also on the narket during the 

first quarter of the 20th century. Although the 

location of manufacture is presently unknown, a 

patent date of July 20, 1910 is indicated on the 

bases of these cups. 

Several varieties of yellow clay cups were 

apparently being made and used almost exclusively 

in the Escambia County, Florida area during the 

early 1930's. Although their ~aste was consistent, 

shapes and sizes varied greatly suggesting temporal 

distinctions in the styles or perhaps different 

manufacturers . 
An unnamed Jacksonville company, possibly associated with Charles Herty's business, manufactured a 

cement cup in the mid-1930's. Experimental glass 

cups were also made in Jacksonville during the 

late 1930's. 

As early as 1914, galvanized iron cups were on 

the market. Styles included the flower pot shaped 

Birdeye cup, the trapezoid shaped Buzzard wing cup, 

and a variety of metal oblong boxes. During the 

1920's and '30's an array of tin, galvanized iron 

and aluminum cups were being manufactured for use 

in collecting pine resin. 

In a final attempt to produce quality resin free 

of leaf litter and other debris, steel oblong 

boxes with a fired enamel finish were used during 

the waning years of the industry. 

Another source of data for establishing a 

chronology of the naval stores industry in Florida 

is the development of specialized tools used in 

chipping and dipping the pine gum. Five technological innovations occurred in the industry's 

peak years between 1900 and 1935 were in collecting cups. During the latter 50 years of the 

industry at least 38 new tools, equipment and 

extraction methods were adopted and accepted, 

over half of which occurred between 1942 and 1958. 

The common chipping tool known as a hack replaced axes and single bevel hatchets in the first 

half of the 19th century. Further advancements 

were made in design during the early 20th century 

with the introduction of the So. 2 hack in 1900, 

the No. 0 hack in 1910, and the detachable blade 

hack in 1915. These early hacks, which were 

attached to a handle and weight, continued in use 

throughout the course of the industry. 

To accompany the new extraction methods, a 

broadaxe for mauling the incision into the streak 

was introduced in 1908 to replace the boxing axe 

in use since 1700. A puller, invented in 1865 to 

chip high streaks, was still in use in at least 

the late 1930's. 

In 1918, the hogal was invented to smooth the 

bark for gutter insertion and chip subsequent 

streaks. Chipping paddles to prevent chips from 

falling into the cup were introduced during the 

late 1920's. Two styles of specialized buckets 

and dip paddles were invented in the 1930's to 

replace the dip spoon previously in use since 

1750. 

It is apparent from the preceding discussion 

that historic archeological sites related to the 

naval stores industry provide a potentially 

important source of data for the study of status 

differentiation and the evolution and geographical distribution of harvesting technology. 

Unfortunately, a review of the results of 

cultural resources inventory and assessment surveys conducted during the past several years 

indicates that sites associated with the naval 

stores industry, with few exceptions, have been 

"written off" as an insignificant cultural resource. It is urged that future investigation~ 

conducted i-n Florida and other states make every 

effort to more appropriately consider and evaluate 

this valuable historic resource during the inventory compliance and preservation process. 

LITERATURE CITED 

Clements, Ralph W. 1979. Personal communication, 

Naval Stores Research Specialist, CSDA Southeastern Forest Experiment Station, Olustee, FL. 

Hickman, Hollie. 1962. Mississippi Harvest, 

Lumbering in the Longleaf Pine Belt, 1840-1915, 

University of Yississippi. 

Otto, John Solomon. 1975. Status Differences and 

the Archaeological Record: A Comparison of 

Planter, Overseer, and the Slave Sites from 

Cannon' s Point Plantation (1794-1861), St. 

Simon's Island, GA. Ph.D, dissertation, Department of Anthropology, University of Florida, 

Gainesville, FL. 

Otto, John Solomon. 1977. Artifacts and Status 

Differences - Com~arison of Ceramics from 

Planter, Overseer, and Slave Sites on an Antebellur! Plantation: liesearch Strategies in 

Historical Archeology, edited by Stanley South. 

New York: Academic Press; 91-118. 

Otto, John Solomon. 1980. Race and Glass on Antebellum Plantations: Archaeological Perspectives 

on Ethnicity in America, edited by Robert L. 

Schuyler. New York: Ba3"i~ood Publishing Company, 

Inc.; 3-13.' 

Pridgen, Albert. 1921. "Turnentinin~ in the South 

Atlantic Country." Naval Stores, edited by 

Thomas Gamble, Savannah, GA. 

Schultz, Robert P. 1981."The Original Slash pine 

Forest--An Historic vieti." Proceedings of the 

Managed Slash Pine Ecosystem Symposium, Univ. 

of Florida, Gainesville, FL. 

Shofner, Jerrell H. 1974. Nor is it Over Yet: 

Florida in the Era of Reconstruction 1883 - 1972. 

Gainesville Press. 

Singleton, Theresa Ann. 1980. The Archaeology of 

Afro-American Slavery in Coastal Georgia: A 

Fegional Perceytion of Slave Household and 

Community Patterns. Ph.D. dissertation, Department of Anthropology, Univ. of Florida, Gainesville, FL. 

Shofner, Jerrell H. 1981a."A Postscript to the 

Xartin Tabert Case: "onage as Usual in the 

Florida Turpentine Camps." Florida Historical 

Ouarterly, 60(2):161-173. 

Shofner, Jerrell H. 1981b. "Forced Labor in the 

Florida Forests, 1880-1950." Journal of Forest 

History, 25(1:14-26). 

Smith, Samuel D. and Stephen T. Pogers. 1979. A 

Survey of Historic Pottery Making in Tennessee. 

Div. of Archaeology, Tenn. Dept. of Conservation. 

U.S. Dept. of Agriculture. 1934. Status Atlas Records, Apalachicola Natl. Forest, Tract A-1, p.3. 
Cornunity Forestry in Mexico' s Natural Forests: Abstract. Seven years after Mexico's National 

1 Institute for Research on Blotic Resources [INIRB) 

The Case of San Pablo Macuiltianguis initiated a community forest industry project for 

rural development in a Zapotec village in the 

mixed pine-oak forests of highland Oaxaca, the 

results and the process are evaluated, In addition 

to problems of inadequate technology and t echiology 

transfer, social factors including the migration 

of local people to urban areas for work and education 

has created a labor shorcage which has affected the 

forest industries. It 1s suggested that demographic 

dynamics like these nay imwse unexpected obstacles 

to the Mexican policy of encouraging communityowned small-scale forest industries. 

Laura c. snookL 

Keywords: Emigration, rural development, social 

forestry, technology transfer, 

Seventy percent of Mexico's 40 million ha of 

forests are in the hands of nearly 8000 'ejidos' 3 

and indigenous (Indian) communities whose communal 

rights to the land cannot be bought or sold (SEP 

1981 ; SRRH/SF 1984 ) . Furtheu , the approximately 

10 million peasants who live in Mexico's forested 

areas are among the poorest people in the country 

(de La Madrid 1983). Therefore, Mexico's national 

forestry policy seeks to achieve the double objective of stimulating forestry sector production at 

the national level and providing a basis for socioeconomic development of forest communities, by 

organizing forest landowners and integrating them 

into forest harvesting and transformation activities (SFF 1981; de la Madrid 1983; Castanos 1984; 

Ley Forestal 1960;1986). 

However, while a number of community forestry 

projects have been initiated in different parts of 

the country (SARH/SF 1984), the process of developing, imp1 menting , and evaluating the methods 

for achieving forestry and rural development objectives among Mexico's peasant communities is just 

beginning. It is hoped that this review of seven 

years of experience in the community of San Pablo 

Macuiltianguis on the part of INIREB (Mexico's 

National Institute for Research on Biotic Resources) 

will contribute to this process. 

BACKGROUND m7D SETTING 

San Pablo Macuiltianguis is an indigenous 

Zapotec community of about 1600 people, located in 

the highlands of the Sierra de Juarez, in 

the state of Oaxaca, Mexico. Their communal 

property includes approximately 5000 ha of commercial temperate forest at an average elevation of 

2400 m, mostly dominated by pines (Pinus patula, 

P. pseudostrobus, P. rudis, P. ayacahuite) and 

oaks (puercus laurina, (3, ruqosa, Q. crassifolia, 

Q. excelsa, 9, candicans, and p. salicifolia) 

(FAPATUX 1962; Perez & Perez 1984). 

Until 1959, San Pablo Macuiltianguis was not 

accessible by road, and the comunity lived off 

of subsistence agriculture and peddling goods 

among the highland villages and between these 

villages and the cities of Tuxtepec and Oaxaca, 

three days walk away down the mountains (Garcia 

1972; KMETICAl 1980; Perez & Perez 1984). All 

this began to change when the forests of San Pablo 

Macuiltianguis and other communities of the EFerra 

de Juarez were concessioned to the first newsprint 

paper mill in the country, Fabricas de Papel Tuxtepec (FAPATUX), as its source of pine wood for 

cellulose (Diario Oficial November 12, 1956). A 

highway and a web of lumber extraction roads were 

built through the Sierra and its forests in 1959, 

and the economy of San Pablo Macuiltianguis began 

to shift towards forestry. 

'presented at the symposium 'Current Topics in 

Forest Research: Ehphasis on Contributions by 

bornen Scientists' cosponsored by the USDA Forest 

Service Southeast Station and the University of 

Florida Department of Forestry, Gainesville, Fla., 

November 4-6, 1986. 

'~esearcher, National Institute for Research 

on Biotic Resources (INIREB), Apdo. postal 63, 

Xalapa , Veracruz , Mexico, 

3~he *ejidol is a communal land grant made to 

peasants as part of Mexico's Agrarian Reform. 

Under the terns of the concession, the comunity 

had no right to sell their wood to buyers other 

than the paper company, nor could they transfom 

it themselves. However, cjommunity members worked 

as loggers, paid by the m for pine bolts cut and 

delivered to roadside for the paper company. The 

company also paid forest use payments known as 

'derecho de monte' to the comunity as a whole, 

most of it deposited directly into a trust fund 

for community development. 

During the first few years of the concession, 

as many as 80 men from Macuilti3nguis worked as 

loggers, cutting up to 12,000 m /year (mETICAL 

1980) or more (Carlos Ruiz, pers. corn.) of their 
allowable annual cut of 21,000 m3/pine (FAPATUX 

19771, Subsequ~~tly, conflicts between the ccmunity and the paper company over ebe price paid for 

their mod (or labor) and tke difficult swrking 

conditions in the forest, led to a work stoppage 

between i96E and 1972, 

During tkis paid, the men of San Pablo &lacuiltiangiais did no logging, To compensate for the 

loss of their principal source of income, many 

migrated to distant cities and the L'nired States 

(Garcia 19721, Men forestry aceivities were 

reinitiated in 1972, under a more favorable agreement with the paper cornparay, fewer men than before 

worked in t3e forestg GcLivering ax average of 

only 5000 m /yea, only one fifth of the annual 

allowable cut, or even less ( comtunity archit-es) , 

The cornunity of Macuiltianguis felt their 

relationship with the paper company was unfair. 

Conscious now that their forest represented ""green 

goldf* ",they began to look for ways to obtain 

greater benefits from the exploitation of this 

comunity resource, 

THE ESTmLZSmEKT OF A COYiPiiUNAL FOREST INDUSTRY 

In 1977, four years before the end of the FAPATUX 

concession, the cornunity of San Pabfo Macuiltianpis made contact with ~NIREB, and requested their 

suppout in sstablishing a forest industry in the 

comunity, INIREB, in particular their Laboratory 

for Mood Sci~rice and Technology (L>=CLTEkA 1 was 

interested in evaluatingthe process of technology 

transfer to determine how their scientific knowledge about natural resources could be integrated 

into the production process. "We did not want to 

collect information and make conjectures about 

a at the cormunity could do with their resources, . 

lCNlt to initiate a process, a dynamic, and to learn 

&out it by evaluating not only the difficulties 

that came up, but also the com.unity% capacity to 

ovscome the difficulties generated during this 

process" ((BtV1ETICkL 1980), 

Both the cornunity and XNIREB bird hopes that by 

providing opwrtunities for stable aplolment in 

local forest industries the rate of migration from 

San Pablo Macuiltianwis could be slow&, During 

the work stoppage, 56% of the economicaily active 

ppulaticn had dgnated (Garcia 19721, and since 

then about 39% of the population was living outside 

the cornunity at any given time (mE"PICAL 1980; 

Perez & Paez 1984). 

""We expected that a peasant industry would encourage the forest owners to stay and work in their 

comunities; and that a comunity indust~g would 

produce economic resources which would be reinvested 

directly into the comunity,,,a communal industry 

would serve as a lever, with rnultipliev effects, to 

stimulate the developmat of cornunities which were 

stagnating, slipping backwards, or had a slow or 

erratic dex~dopnmt dynmic" WIETSGAII 1980 ) , 

hIhi3.e the cornunity sf San Pablo Macuiltianguis 

wanted .i;o establish a pine sawmill, the terns of 

the concession and the interests of the paper 

company did not pexmit them to use the pines in 

their forest, As a consquence, and to achieve a 

great= degree of transformation, more value added, 

and more potential for Local miploymat, the 

Institute sugg~std that the cornunity invest 

instead in a mall factory to produce tool handles 

from the unexploited oaks in zhe forest (mETICAL 

19eo 1, 

In 1978, permission was ebtained frm FAPATUX to 

use the oaks, and with $700,000 pesos ($30,000 

US ac that time) which had aecmulated in their 

trust account of forest use payments, and a bank 

loan for $i,000,000 pesos ($44,000 US), the comunity invesced in a flatbed cruck, a building, and 

the simple lathes and sanders necessary. INIREb 

helped them with the complicated papemork and 

other efforts necessary to achieve this, and to 

obtain che electrical connection to powev the 

factory. The oak was cut and split by comunity 

m-ers during "tequios" , unrmunerated c 

labor sessions, and in 1980 the tool handle factory 

begdn functioning, staffed by 16 members of the 

cornunity (~evez & Perez 1984). 

There were still many problems ahead, Among 

others, thousands of h er handles were refused 

by the buyer because they did not meet quality 

control standards. Problems with maintenance, due 

in part to the poor state of the machinay when it 

was bought second band, and in part to the lack 

of training of personnel in this field, led to 

low rates of production, Problems in personnel 

managment derived from the form of payment (which 

was changed from an hourly to a piece rate with 

incentives) and absenteeism due to agricultural 

labors, This made it very difficult to achieve 

a continuous rate of production and integrate the 

factory's output inrc a supply system for potential 

buyers. 

By this time, INIRE23 had been participating alongside the community for nearly three years. They 

felt that many of the prcblems which were impeding 

the development ofthe industry should be resolved 

by the communal assembly, autonomously. They did 

not want to find thaselves taking over the process 

and interfaing with the development of a sense of 

responsibility and duty on the part of the comunity, so they withdrew (METICAL 1980). 

THE END OF THE COPJCESSIW AND THE INSTALLATION OF 

THE SAMILL 

At the end of 1981, the paper company's 25 year 

concession over the forests of the Sierra de 

Juarez ended. The comunity au~korities decided 

to install, ac last, the pine samill that the 

cornunity had always wanted. Using n advance 9 paid by the paper company for 5000 m of pine md, 

the cornunity bought a new samill, and installed 

it in 1982, with the technical assistance of 

FAPATUX, 

By the end of 1982, San Pablo F'"iacuiltianguis 

basted the complete infrastructure necessary for 

an integral forest utilization system. They hag a 

forest with an allowable annual cut of 25,000 rn 
3 of pine and 20,000 m of oak, a complete network 

of exLraction roads, a market for cellulose products, 

a pine sawmill, a factory for oak tool handles, 

and a carpentry shop; all belonging to the community 

as a whole. The harvesting, transportation and 

transformation activities provided employment for 

approximately 100 people. 

However, the tool handle industry had shut down 

due to problems with the machinery, lack of raw 

materiais (oak was more difficult to fell and buck 

than pine, and then had to be split to be processed), 

lack of labor, and administrative problems. The 

sawmill which began working in November .,gas closed 

dom by the end of the year for lack of wood. The 

timber harvesting activities were paralyzed due to 

lack of manpower in the forest, reflecting in part 

a lack of working capital to pay than with. 

In early 1983 the authorities of San Pablo i"i acuiltianguis returned to INIREB to request 

counsel and support. The Institute agreed to 

analyze the forestry situation in the community as 

soon as funds could be obtained to support the 

necessary research. BEfore these arrived, a major 

forest fire swept through the forest, af f ecting 

about 3000 ha in May 1983 (Quintero, Servicio 

Forestal Oaxaca, pers, com.). 

Conscious of the importance of cutting the 

damaged trees before they rotted, and their 

inability as a communi y to cut such a volume 5 (estimated at 80,000 m , Quintero pers. corn.), the 

authorities of San Pablo Macuiltianguis contracted 

with the paper company to extract most-of the 

burned trees. The logs cut at 2.62 m would be 

delivered to the community sawmill and the bolts 

(1.25 m) would be sold to the paper company for 

cellulose. Timber extraction began in August 1983 

and the sawmill began to function again (largely 

with workers from neighboring comunities) until 

the director (a member of the community) resigned 

at the end of the year, in protest to the heavy 

time demands and his low salary. 

INIREB ' S EVALUATION 

In April of 1984, the yard of the sawmill was 

full of logs, and the salvage cutting continued. 

A new director for the sawmill was named by the 

comunity assembly, and sawing activities resumed. 

It was during this month that the author, with a 

grant from CONACyT (Mexico's National Council for 

Science and Thchnologk*) , returned to San Pablo 

Macuiltianguis with a team of researchers (Masters 

students in Ecology and Biotic Resources at INIREBJ, 

and three outside consultants, to evaluate community forestry activities and advise how their problems might be resolved, Seven separate studies 

were carried out and their results delivered to 

the comunity in June 1984. This paper draws on 

several of them. 

The major obstacles to the development of the 

forest industries in San Pablo Macuiltianguis were: 

I) problems with raw materials supply; 2) an 

insufficient labor force; and 3) a lack of administrative and technical capacity. Therefore, in 

addition to evaluating xhe productive forestry 

activities per se (forest harvesting, the sawmill, 

and the cool handle industry), a socioeconomic 

survey was made of the community. 

"he comunal forest industries of San Pablo 

:Xacuiitianguis have been shut down periodically 

for lack of wood supply. This results fran both 

techni a1 and social faccors. The sawmill requires t3 8400 m of pine roundwood/year to produce 8000 

board feet/day during 222 working days a year. 

This volume represents just over a third of che 

allowable annual cut of pine. Ho~ever,~bei;ween 

August I983 and April 1984, of 16,000 m of pine 

harvested, only twenty percent was cut as sawlogs, 

a proportion which would provide less than half of 

the samnill's annual needs (J. Mayoral, R. Perez, 

pers. corn.]. Thls despite the fact that the forest 

study indicated that half of the standing volume 

was of adequate size and quality for sawlogs 

(FAPATUX 1977 ) . 

In part, this proportion reflected the paper 

mill's interest in supplying its own needs for 

cellulose over community needs for sawlogs, during 

their post-fire salvage contract, but previous and 

simultaneous harvests carried out by the comunity 

itself also cut big trees to bolt size. This has 

occurred largely as a result of the selective 

cutting regime applied to the forest, combined with 

inadequate extraction technology. 

Although mechanical winches have been used on 

occasion to haul logs uphill to the road, most of 

the wood cut in San Pablo Macuiltianguis is rolled 

downhill manually to the extraction rnads (the 

average slope is nearly 20 oercent). Since the 

official silvicultural system limits earactions 

to 30 to 40 percent of tke pine volume (15 to 25 

percent of tztal volume). the density of residual 

trees is very high (see Snook & Negreros 1986). 

As a result, the rolling of large logs among the 

trees which are left is difficult, and loggers 

generally buck all logs to 1.25 m bolt length if 

they are located more than 50 m from the road, 

regardless of their diameters (which may reach 80 

cm or more) and optimum use. 

A more intensive silvicultural system (which 

would also improve regeneration and growth, see 

Negreros and Snook 1984; Snook and Negreros 19861, 

combined with improved extraction methods, would 

permit the extraction of large logs at sawlog 

length, thus assuring sufficient raw material supply 

to the community sawmill, and additional income 

to the community. 

A more complex aspect of the raw materials 

supply problem for the community forestry industries 

of San Pablo Macuiltianguis is the labor supply. 

Since the beginning of the concession, there has 

been insufficient labor to extract the annual cut 

of pine, much less the oak, in San Pablo Macuiltianguis. In 1984, despite a call for workers in 

neighboring communities, only 12 teams of loggers 

were available3 of the 25 or more necessary to cut 

their 25,000 m annual cut of pine during 37 working 

weeks a year. 

Only the forest fire of 1983,and the 
resulting community contract with the paper 

factory to extract the damaged trees, has assured 

the sup~ly of raw materials to the sawmill. 

However, this contract has a fixed time limit. 

Unless it is continr,musly renewed, the problem of 

raw materials supply will reappar. 

The lack of manpower available to cut wood is 

in part a function of the technological problems 

of extraction which reduce the productivity and 

thus the earnings of loggers, who are paid 

according to the volume of logs delivered to 

roadwde. A time and motion study revealed that 

a pair of loggers spent nearly 60 percent of their 

time moving logs with a pevee and debarking bolts 

for cellulose by hand with axes. In addition, by 

producing mostly boltyood for cellulose, loggers 

earned 40% less per m than they would have had 

they produced sawlogs. 

If boltwood for cellulose were sold with bark, 

and if the time spent moving logs by hand to 

roadside could be cut in half by modifications in 

silviculture and improved gxtraction techn~logy,~ 

loggers could produce 36 m /week instead of 26 m / 

week, and fewer loggers would be necessary to cut 

the same volume of wood. If they also produced 

35% of their total volume as sawlogs, they could 

not only assure the supply of wood to the sawmill, 

but would also earn almost 50% more than at 

present. Such modifications would contribute to 

the resolution of the raw materials supply problem 

in two ways: by increasing productivity and by 

providing greater incentives and rewards for 

logging. 

The problem of insufficient labor supply 

affects the wood transformation industries as 

well. In 1984, only 7 percent of the economically 

active men in kacuiltianguis were working in the 

forest industries, while 60% of the workers came 

from neighboring communities, This reflected in 

part the low salaries, which Macuiltianguis 

citizens considered inadequate. But while the 

maximum earn'n s of a logger result from the 3 value of a m of wood and his own productivity, 

the salaries of the forest industry workers are 

low because the communal assembly fixed them 

tha& way. 

While it is desirable that forest industries 

belong to the communities which own the rights 

to the forest land, this has implications which 

can in fact create obstacles to their own industrial development. In San Pablo kacuiltianguis, 

where the forest and the industry belong to the 

community as a whole, every member of the community has an equal right to share in t h e p r o f i t s 

of the forestry activities, Since only 13% of 

the members work in forest-related activities, 

the majority of the community wants the industry 

to produce a high profit margin rather than 

paying good salaries, In 1984, most workers 

fzlt that their wages were inadequate, yet sawmill earnings were scheduled to be invested in 

additional infrastructure (including vehicles), 

or applied to profits, 

The repeated suspension of production for lack 

of labor or raw materials, or subsequent to the 

resignation of the diff erent directors of the 

forest industries, has occurred partially because 

of this conflict between allocation to profits and 

allocation to salaies. With an increasing proportion of forest workexs from other co~munities, one 

would expect this conflict to worsen. 

E~igration also affects the avaiaability of 

workers in the forestry activities of the comunity. 

In 1984, 60% of the men between 16 and 35 years of 

age were living outside the c unity, naif of them 

working (many in the US), and half stcdydnq, This 

demographic dynamic could be significant for the 

future of the f. rest industries in San Pai-,lo kacuiltianguis, and may be indicative of a pattern 

echoed in other forest communities in P.exico. 

The emigration of economically active citizens 

from San Pablo hacuiltianguis began during the 

second World War, when American agricubturalists 

came to Mexico to hire 'braceros' to work in the 

American fields. A number of men went from San 

Pablo Kacuiltianguis. heariy 25 years later, 

during the work stopmge protest against the 

paper factory, more than half of the economically 

active population emigrated, both to hexico City 

(75%), and to the UniPed States (15% 1 (Garcia 

1972), sending money back to support their £am- lies. 

This pattern of emigration from San Pablo Wacuiltianguis may reflect the traditional mobility of 

be Lapotecs. Before the forest concession, most 

of the members 6f the community were peddlars 

(Garcia 1972), and the goods they sold weae not, 

for the most part, products of their own fields 

or labors, but coffee, avocados, and other products 

gzom the neighboring villages of the Chinantecs. 

Because they derived their income principal.1~ from 

long-distance trading rather than the production 

of goods from a fixed point, perhaps the Macuiltecos are not pasticularly attracted to the idea 

of becoming industrial workers with fixed places 

and times of work. In fact, 11 percent of the 

faxnflies of San Pablo Macuiltianguis are merchants 

today, maintaining 20 stores in the community. 

The multiple devaluations of the peso during 

the past 5 years (from $23/dollar in June 1981 to 

$800/dollar in November 1986) have provided an 

additional incentive to emigrate to the United 

States. Accumulating savings i& important to 

citizens of San Pdalo Macuiltiangrris for several 

reasons, One of them is the community tradition 

of unremunerated citizen participation in the 

community government, Some of these jobs, for 

example, the committee responsible for communal 

natural resources, including the forest, now 

require full-time dedication, A serving citizen 

may have to maintain his family with no incame 

for as long as three years. There are so many 

community responsibilities, &hat an average 

citizen of San Pablo Macuiltianguis is involved 

in one or another during 7 to 10 years of his 

life. (If a citizen does not serve, when named 

by the Assembly, he loses his rights as a member 

of the community, and forfpxts all property). 

Another demographic phenomenon which affects 

tie habor supply for forest industries in San 
Pablo Hacuiltianguis, is the emigration of young 

pemple from the community to study, After graduating from secondary school in the comunity, 30 

percent of the young people go tr the cities to 

study in technical schools or high schools, Some 

of them continue through university, These young 

people with their technical diplomas or professional 

degrees are unlikely to return to the comunity 

because the available employment does not require 

or remunerate this level of preparation, and life 

in a small muntain village does not offer the 

stimulation of a city, While a nuaer of young 

people from San Pablo Nacuiltianguis have seudied 

forestry, in 1984 only one of them was wrking in 

the communal forest industries, (To work in 

forestry per se, forestry graduates must obtain 

government eznployment, since by law only the forest 

service can carry out managwent responsibilities, 

regardless of the ownership of the forest land), 

Ccmunity interest in advanced education has 

other implications for the local forest rndustries. 

Sixty percent of the parent5 in San Pablo Macuiltianguis consider expenses associatd with the 

education of their children to be mong the most 

significant of the family expenditures. In L984, 

39% of the families were maintaining one or two 

children in some city, to study. The cost of 

maintaining a child in a provincial city was 

$5000 to $10,000 pesos a month, and up to $15,000 

pesos a month in Piexico City, The salaries paid 

in the communal forest industries wse abut 

$15,000 pesos/month at that time, clearly inadequate for providing for the educational goals of 

many families. (In #me, 1984, the pesoidollar 

exchange was $191/1.00). 

'rhe problems of raw matexials supply and labor 

availability wse observed to be complex, involving 

the interaction of sociological, cultural, econmic, 

technological, and even legal factors. Sos* of 

these reflect the very processes of socioeconomic 

development, and changing expectations, kany are 

linked to structural features external to the 

community. For example, the selective extraction 

regime applied to MacuiltianguisVorests is the 

official silvicultural system defined by fdexal 

forest service guidelines, and applied t o a l l 

Mexican forests (see Snook & Negreros 1986, in 

this volume), By the same token, it has been 

paper company policy to buy debarked logs, The 

peso to dollar exchange rate, in part a function 

of international oil prices, has probably affect& 

the community's labor supply by acouraging 

emigration to the United States, 

Yet many operational problas within the forest 

industries were perceived as a function of insufficient technical and administrative capacity 

within the comunity, or inadvate technology 

transfer, In fact, the inexperience of cornunity 

leaders, who named by the comunity assembly, gameby 

undertook to manage the fledgling forest industry 

complex (first the oak tool handle factory, then 

the sawmill and timber extraction activities), 

were hampered in these undertaking by their lack 

of training and skills, Maintenance and marketing 

problems have already been mention&, ~"'artu~ of 

the sawmill was delayed nearly a year aft= it was 

~nstalled, hecause no working capital had been 

budgeted to pay workers or loggers. The lack of 

accounting skills on the part of the comunal 

committee which had been nm& by the assably to 

direct the foresay activities, Id to accusations 

sf fraud, and cornunity doubts abut the economic 

ptential of the oak tool handle 16x3 to its 

virtual abandonment, hor bad an evaluation of 

future raw materials supply in lrgbt of the fire 

ed with the reswsible forest 

service pc rsonnel , 

IhIREB had off=& courses in maeh~nexy maintenance and adat~nistration for hamiltianguxs even 

before the tool handle factory was install&, but 

the cornunity did not send their personnel, pahaps 

because these were to take place at Institute 

headquarters, a full day away by bus, Gther short 

courses, on tree felling and aecsuwting, had been 

offered at the papex compny's nearby forestry 

p in the Sierra, but only one cornunity mmber 

had gone in each case. 

However, the mmunity bad arranged for a Sew 

of their workers to spend a few weeks trainrnq in 

anotha sawill, and had hired a technicinn to help 

them start up their ow =mill, They had also 

requested that the paper company send one of the* 

accountants to help thm organize their mks, 

Cornunity Zeadms had come twice to INXmB to 

xeqest help, first in setting up and thew in 

diagnosing their forest industry, And &ife it 

was not easy to axanae mrking sesslons with 

comunity leaders to dsliva and discuss the 

results of those evaluations, they may have been 

taken into account, and act& upon, since thew, 

(The results of the analysis describd in Snosk & 

Negreros 1986, sn thxs volusne, which had been 

present& to the assably in 1983, were found later 

to have be= us& to define terns for the salvage 

cutting contract sign4 with the paper company 

aftex the forest fire), Meanwhile, the samibl 

seas to continue to function, 

This overview of the San Pabl0 Nacuiltianguis 

experience in forestry devdopment has been fax 

frm e*austive, yet ceatdn observations can 

be made, To begin wish, a dynmic process was 

initiatd wflm the forests of Ssr gablo Macrailtianguis were recclgnizd as a remurce, and the 

ltyiias been an active protagonist, parti cusisee the wrk stoppage sf 1968, mile 

vest& INIREBk advice on establis 

ity forestry industsy in 1977, the c 

respond4 to the end of the forest concessiw in 

1981 by ahndoning the oak tool handle faetsrqa and 

establish& the pine samilf on their om initiative, 

Tbae have cwtainly been weaknesses in the 

pmcess of technology transfa, *ish have 16x3 

ks inefficienq, pmbims, shutdoms, and a pstatial for continuing or wrse difficulties in 

the Sutusre, In part, these my have reflect& the 

vay dynmism sf the e nity, *ich has hen 

more adaptive than pasistent in its respnse to 
obstacles. The difference in perceptions ACKNOWLEGElYl ENT S 

between INIREB and the cornunity about the best 

solution may also have impeded adequate follow- e 

This article is adapted from a piece submitted through, For example, the oak toof handle factory to Biotica, the journal of INIREB, Funding for does seem like the optimal forest industry to 1 INIREBes work in San Pablo Macuiltianguis was 1 hprove forest utilization and silviculture (see provided by CONACyT, Hexicues National Council for Negreros & Snook 1986, in this volume), and maxi- Science and Technology, Expert consulting by mize emplopent and profit per unit volume of Dr. J. Kachleen Parker, social ecologist, was mod, Yet the cornunity perceived the sawmill, supported by the World Wildlife Fund, US, Juan probably a simpler operation and less difficult Manuel Chavez, Emiliano Sanchez, Francisco Hernawto supply and maintain, as more desirable. dez, and Jonathan Flores, Masters students at I 

Among the most important lessons from the 

San Pablo Macuiltianguis experience, however, is 

the demonstration that certain key assumptions 

about the cornunrey forestry development process 

were not borne out, For one, emigration was 

not slowed by the creation of jobs in the community -- rather, the industry suffered from insuf 

ficient labor supply. In this case, the seeming 

anomaly may reflect traditional cultural values, 

changing expectations, or international financial 

relationships, but apparently this assumption 

has been shown not to hold in ot-her rural develop 

ment experiences as well (Rhoda 1979). 

An implicit hope of the Hexican community 

forestry development policy has been to increase 

the level of timber harvesting, and thus reduce 

:~e sevse shortfall of cellulose, which is 

currently met by imports, Yet it appears that 

the rhyth of extraction in San Pablo macuiltianguis dropped to levels inadequate even to supply 

ity industries, until tpe forest 

ent salvage contract. Part of 

this may reflect other forestry policies (for 

example the official silvicultural system) whose 

effects my indirectly discourage 

ticipation in forestry, It would appear that 

specific strategies and tactics should be developed 

to provide incentives and means for increased 

levels of harvesting. 

Finally, it is humbling to acknowledge that 

the process of forestry development, even in a 

seemingly isolated mountain village, is so complex, 

and subject to so many unexpected and constantly 

changing factors, many seemingly unrelated to 

forestry. One wonders what responses might be 

expected in connection with the new Mexican 

forestry law of 1986, the new US immigration law, 

or the increasing unemployment of Mexican university graduates resulting from the country's 

deepening economic crisis and cutbacks in government spending, What dues seem clear among the 

mind-boggling linkages and uncertainties of 

this cornunity forestry development dynamic, is 

that the success of Mexico's forestry policy 

depends largely on the understanding of sociological processes, 

INIREB, work& on the collection and analysis of 

data for the sociological and indaastrial evaluation of the community. 

LITmTURE CITED 

mETIGAL, 1980, Impactos de la Politica Forestal: 

Contradiction de 10s Modelos Capitalista y 

Campesino, INIREB, documento interno, 

Castanos, L,J, 1984, Los Recursos Forestales 

cmo factor de desarrollo. Alternativas Tecnologicas 6, Academia Mexicana de Ingenieria; 

Consejo Nacional de Ciencia y ~ecnologia, M~CO 

D.F. pp, 141-150. 

FAPAgUX (Fabricas de Papel Tuxtepec), 1962, 

Pr~yeeto definitivo de la seccion de ordenacion 

#1, Edo, de Oaxaca, Mexico. FAPATUX, documento 

interno, 250 pp, 

FAPATUX (Fahricas de Papel Tuxtepec). 1977. 

Proyecto general de Ordenacion, Estudio 

Forestal ~otograxunetrico. Secciones de 

Ordenacion I, 1x1 y IV, Uni&d Industrial de 

Explotacion Forestal. Oaxaca, 

Garcia R., I, 1972. Estudio sociologieo de la 

indigencia en el municlpio de San Pablo Macuiltianguis, Sierra de Juarez, Oaxaca. Tesis 

profesional, UNAM. Facultad de Ciencias 

Politicas y Sociales. 

de la Madrid, K, 1983, Mandato popular y Mi 

Cmprorniso Constitutional, Plan Nacional de 

120 1983-1988. Secretaria de Programcion y Presupuesto. Mexico D.F. 

Negreros, P, & L, S,ook, 1984. Analisis del 

efecto de la intensidad de corta en la regeneracion de pinos en un bosgue de pino-encino, 

Ciencia Forestal 47 ( 9 ) : 48-61. 

Perez P., E, & G. Perez C. 1984. Estudio ecologico floristic0 y el significado economico de la 

vegetation en la comunidad de Macuiltianguis, 

Oaxaca. Tesis profesional, UACh, Departamento 

de Boves, 

Rhoda, R. 1979, Development activities and ruralurban migration: Is it possible to keep them 

down on the farm? Office of Urban Development, 

Bureau for Development Support, Agency for 

International Development, Washington, D.C. 
SARH/SF (Secretaria de Agricultuta y Recursos 

Hidraulicos/Subsecrearia Forestai,l984, Mexico 

Forestal. Cifras 1983. 59 pp. 

SEP (Secretaria de Educacion Publkca), 1981, 

Guia para la planificacion de actAvidades 

forestales. Mexico, D.B, 

SF (Secretaria de Agricultwa y Recursos Hidraulicos, Subsecretaria Forestal y de la Fauna), 

1981. Progranra NacionaL Forestal 1982. Hexico 

D. F. 

Snook, L, 1984. El papel def desarrollo tecnologin, en la resolution de algunos pzcobl 

si%vicolas, Alternativas Tecnologicas 6. 

Academia Mexicana de Ingenieria, Conse jo 

Nacicnal de Ciencia y Tecnologia, Mexico D.F. 

pp, 219 - 224. 

Snsok, L. & P. Negreros, 1986. Effect of 

Kexicses selective cutting system on pine 

regengvation and growth, Proceedings, 

Spposium on Current Topics in Forest 

Research : Bnphasi s on Contributions by 

Women Scientists, USDA Forest Service 

Sutheast Station ; University of 

Deparment of Forestry, c;nane%ville, Fla. 

November 4-6 l9@6, 
Jacqueline L. Raymond 2 

Diffusion of Innovations: A Sociological Approach Abstract,--Methodology based on diffusion of 

innovations research was developed to identify 

to the Nonindustrial Private Forests Challenge I nonindustrial private forestland owners who are 

opinion leaders and investigate their traits, 

attitudes and values. The sample was composed of 

sixty-four respondents who live in the South 

Carolina Piedmont region. They were verified as 

"early adopters." 'ore than one-half of the 

sample valued lifestyle enhancement benefits of 

their forestland more than timber production/ 

economic benefits. This preliminary study lends 

credence to the theory that an interdisciplinary 

approach, similar to that successfully applied to 

farmers, is appropriate to improve technology 

transfer to nonindustrial private forestland 

owners. 

Keywords: Change agent, early adopter, 

information source, lifestyle enhancement, opinion 

leader, technology transfer. 

This paper presents results of a study designed 

to develop methodology to identify opinion leaders 

who own nonindustrial private forestland and to 

search for common traits, attitudes and values. 

Understanding the attitudes and values of opinion 

leaders can enhance technology transfer programs 

to im rove forest management on private forest1 and. S 

Numerous studies have been made of the private 

forestland owner. In general, the intent of 

technology transfer efforts has been to increase 

wood production on private land in a manner 

similar to wood-using industry land management 

practices. However, the goals and attitudes of 

private owners differ from those of the wood-using 

industry. Lip service has been given to private 

owner objectives, but successful technology 

transfer programs must be designed to satisfy 

these goals. Technology transfer between professional foresters and private landowners may be 

expedited by an interdisciplinary approach 

combining social science--the study of people-- 

with forestry. 

SOCIOLOGICAL BACKGROUND 

Rural sociologists have used diffusion of 

innovations research to improve technology 

transfer to farmers by defining their attitudes 

toward their land, their enterprises (e.g., crops, 

livestock) and new farm practices, Diffusion is 

that type of communication by which an innovation 

spreads among members of a social system (Zaltman 

et al. 1973). An innovation, in sociological 

terms, is any idea perceived as new by the 

receiver. This study was designed to test the 

applicability of some diffusion of innovations 

meehodology to private forestland owners. 

Rogers and Shoemaker (1971) defined adopters of 

innovations in five groups as innovators, early 

adopters, early majority, late majority and 

laggards or late adopters, Innovators are the 

first 2.5 percent to adopt a new idea, followed by 

early adopters (13.5 percent), early majority (34 

percent), Late majority (34 percent) and laggards 

(16 percent); Muth and Nendee (1980) suggested 

the five categories are appropriate for describing 

forestland owners. Baird (personal communication 

1982) wrote in a problem analysis that the results 

of numerous surveys "indicate forestland owners 

follow a decision-making process that is one of 

the most well-established phenomena in sociology-- 

the innovation-decision process." Applying 

diffusion of innovations research methods to 

categorize forestland owners will allow foresters 

to recognize the early adopter groups and direct 

information transfer programs to them. The early 

adopter category, more so than any of the other 

four, exhibits the highest degree of opinion 

leadership and, therefore, is the key target 

audience for change agents (Rogers 1983). 

METHODS 

Preliminarv Work 

'presented at the National Symposium on Current 

Topics in Forest Research: Emphasis on 

Contributions by Women Scientists, Nov. 4-6, 1986, 

Gainesville, FL. 

'Assistant Professor of Forestry, Clernson 

University, Clemson, SC 29634. 

3~n this paper, private forestland refers to 

nonindustrial private forestland. 

One hundred and forty scientists in the fields 

of rural sociology, forestry and natural resources 

were contacted by mail. The study design was 

based on suggestions of the fifty-nine respondents 

and of other personal contacts. Following pilot 

interviews with research scientists and investigation of questionnaires used in other studies, the 

final 12-page questionnaire and interviewing 

techniques were developed and field tests were 

conducted. 
Eight counties were selected based on statistical data and discussions with the county agents in 

ail eighceen counties in the South Carolina 

Piedmont region, First-stage selection was based 

on three factors used to create a composite 

ranking: (I) income from forest products as a 

percentage of total Land-derived income in the 

county, (2) the percentage of county commercial 

forestland owned by private forestland owners, and 

(3) the number of acres of private forestland in 

each county, Data used are available for all 

South Carolina counties, as we11 as generally 

throughout the United States, Final selection was 

based on four factors: (I) the counties were 

among the top ranked according to the co~posite 

ranking scheme, (2) the percentage of national 

forestland within the county was low (less than 

20% of the tats1 commercial forestland), (3) sio 

major urban areas occurred in the county, and (1) 

the county agent was willing to cooperate and 

relatively enthusiastic about the project, 

Opinion leaders were identified by requesting a 

list from three people in each county who were 

familiar with the county residents, County 

Extension Service agents, South Carolina Forestry 

Commission foresters, and one other local resource 

person provided lists -&ich were prepared independently. 

Sixty-four of the one hundred and ninety-six 

nominees were selected for interviews based ox the 

following criteria: 

I, ,411 opinion leaders named by more than one 

informant were asked to participate in the study 

(except those eliminated by Item 21, 

2. The county agent or commission forester 

(primary informant) was consulted to screen the 

List of nominees, Professional foresters, 

Landowners employing full-time foresters, 

additional members of the same family owning 

forestland mutually, and those persons judged as 

likely to be uncooperative or unknown by the 

primary informant were deleted from the Lists, 

The remaining opinion leaders were ranked by the 

primary informant in each county and interviewees 

were chosen according to this order, 

3. A minixurn of seven and a maximum o: fifteen 

opinion leaders were interviewed in each 3f the 

eight counties, 

Interview Process 

All subjects were personally interviewed by the 

author. Each interview was tape-recorded and 

basted about two hours, Short answers to specific 

questions were written on questionnaire forms 

during the interview. Other responses were 

transferred from the tape to the forms after the 

interviews were completed, The primary goal was 

to establish an atmosphere conducive to 

conversational responses rather than restricting 

replies to forced-choice lists. 

RESULTS AND DIf GUSSFON 

Evaluarion of Informants 

The ability of the county agent an3 the county 

forester to name opinion Leaders was compared by 

developing a '%success .i_r,c?icat~r'~ based on identical noainations, The test revealed the amount 

of cross-over betwee3 informants, taking into 

account the differences in numbers of names 

submitted by the three informants in each county. 

A score of 1-00 would indicate complete agreement. 

Although differences occurred between counties, 

and between agent and forester in the same county, 

the average success indicator was essentially the 

same: agent .32, forester -33. The two types of 

change agents exhibited approximately the same 

informant ability, It is important to recognize a 

limitation to this success indicator test: it 

assumes the agent, the forester, and the third 

resource person had equal facility for recalling 

nanes of opinion leaders and recognizing opinion 

leadership qualities of nominees based on the 

written descriptive characteristics provided by 

the author and enumerated below: 

I, Not the first, but one of the first, to try 

a new idea. 

2, Having more education than the average, but 

not the most, 

3, k leader in cornunity organizations, but not 

usually state or national ones, 

4, Respected by neighbors as a "good manager'" 

of his land. 

5, Owning a moderate area of farm/forestland 

but not the Largest amount. 

6, Getting most of his information about new 

farm/forestry practices from county agents, 

extension bulletins, newspapers, and magazines. 

7. Progressive in his thinking bus not 

radically different from most other people. 

The self-designating method (Rogers 1983) was 

used to verify that the opinion leaders could be 

categorized as early adopters, Combined responses 

to the seven questions on a self-judwent rest 

developed by the author indicated 82 percent of 

the opinion leaders considered themselves early 

adopters and 16 percent considered themselves 

early majority, One person thought he was an 

innovator and one a late majority adopter. 

1 

A diverse population was deliberately selected 

to include a variety of people with regard to age, , 

i 
race, religion, sex, occupation and other characteristics, The only common attribute required for 

nomination was opinion Leadership, Nevertheless, 

many attitudes and traits were shared by a 

majority of the opinion leaders. 

Personal Characteristics 

Most of the opinion leaders sampled were over 

50 years old, male, a farmer, or a businessman, 

Most spouses never worked outside &he hone or were 

retired. The respondents had two or three 

children and considered the family upper-middle 

class or upper class socially and economically, 

The family" annual income was over $20,OC3 with 

nearly equal numbers earning $20-30,800, 

$30-40,000, $40-50,000 and over $50,000, Few 

reported incomes of Less khan $20,000, Most 

opinion leaders believed that their family could 

not get by on less income, although 44 percent 

indicated they could, 

Cultural Characteristics 

The typical opinion leader was of Scotch-Irish 

descent and spent his childhood on a farm, He 

went on a vacation sometime during the past 

12 months, either traveling or to &he beach, He 

liked music, was more likely to read magazines 

than books, and watched television more than he 

Listened to the radio. He had no desire for more 

Leisure time, Many were retired and others 

preferred working to relaxing. Hunting, reading 

and fishing were favorite pastimes when partlcipating in leisure activities. 

Over 90 percent of the opinion Leaders reported 

reading magazines regularly, The most popular was 

"Progressive Farmes,'"Only Li percent of the 

opinion leaders read forestry-related magazines, 

Opinion leaders enjoyed a wide variety of music 

including opera, classical, religious, and swing, 

but '%countryv music was the most popular, Nearly 

one-half of the respondents listed news as their 

favorite television, followed by sports, As was 

the case with magazines and music, a wide variety 

of preferences was given, 

Institutional Characteristics 

A typical opinion leader was married and Living 

with his spouse. He characterized himself as a 

political conservative; only one was a Liberal, 

Seventy percent of the respondents had at least 

some college; 53 percent had a degree, He was a 

member of a Protestant church, usually Methodist, 

Presbyterian, or Baptist, and often one or two 

other social groups and one or more civic, government, farm or professional organizations, but he 

did not belong to a hobby group. The Farm Bureau 

and ~attleman's Association were the two farm, 

business or professional organizations in which 

opinion Leaders were most active. Many were 

members of several other dairy, beef or other 

livestock organizations. About one-third of the 

respondents did not belong to any farm, business 

or professional organization, However, nearly 

one-half of these opinion leaders belonged to a 

forestry-oriented organization or served on a 

forestry advisory committee, 

Twenty-two percent of the respondents did not 

participate in civic or government organizations, 

Those who were active in such groups participated 

in twenty-six different organizations, with the 

Soil Conservation Service and Lions Club ranking 

first and second. Participation in organized 

groups was usually restricted to the Local level, 

not state or national, This was one characteristic which distinguished these opinion Leaders as 

early adopters instead of innovators, 

Lnformation Sources 

One of the key variables in technology transfer 

is information sources, Diffusion of innovations 

research indicates that early adopters get most of 

their information from local change agents, farm 

magazines and extension bulletins, This was true 

of the people in this study, The percentage of 

opinion leaders using each source was: 

Information Source 

County forester 

SCS or ASCS 

County agent 

Farm/forestry magazines 

Industry forester 

Extensioa/research bulletins 

Forestry organizations 

Family traditions 

Paid forestry consultant 

Percent 

85 

7 4 

6 8 

6 6 

5 8 

5 6 

4 7 

4 7 

4 5 

More than 65 percent of those evaluating information sources rated the above sources as "'good,'" 

Other sources rated good by SO percent or fewer 

were a logger or buyer (50), friends and neighbors 

(42), newspapers (40), television (38), other 

forest Landowners (37), and radio (311, 

In discussions with the Landowners, it became 

clear that newspapers, radio, and television are 

good sources of farm technology information but 

little forestry information is received via these 

mass media, Apparently, forestry technology 

transfer programs are not fully utilizing these 

communication channels. 4t should be noted that 

diffusion research has shown thar mass media has 

been most useful for creating awareness, not 

persuasion, 

Forestland Odaership 

The typical opinion leader had lived on or near 

his forestland more than 20 years, many all of 

their lives, Approximately one-%bird of the 

respondents bought all of their forestland, 

one-third inherited it and one-third owsied some 

Land that was bought and some that was inherited. 

The total number sf acres of rural property 

reported by these individuals ranged from 85 to 

12,000, Those reporting acres by forest type 

owned between 30 and 5,400 acres of forestlandThe median size was 300 acres, Sixty-seven 

percent of their rural property was in forestland, 
Most of the forestland was in natural pine or 

mixed pine-hardwood, Only 16 percent was in 

planted pine and 8 percent in hardwoods. 

Most opinion leaders had sold pine and hardwood 

pulpwood and sawtimber and cut their own Christmas 

trees, fenceposts and firewood, Only two people 

reported no sales, One-half of the respondents 

reported making a sale of forest products within 

10 years after acquiring the land. Income from 

past sales had been used for farm, business or 

living expenses; to reinvest in other areas; or to 

pay for the land from which the timber was 

harvested. Only four respondents had used timber 

sales income for reforestation of their land and 

only five planned to use future timber sales 

income for this purpose. 

Nearly 80 percent of those interviewed said: "I 

wish I had invested some money or more money to 

improve my forestland.'' They were aware of the 

increase in prices for timber and, in retrospect, 

thought investing more money in improving their 

forestland for timber production would have been a 

good investment. However, many believed that the 

time for profitable investment had passed, prices 

would not continue to increase, and they did not 

intend to invest money in forestry. 

Reasons for Valuing Forestland 

Opinion leaders gained satisfaction from owning 

their forestland for several reasons other than, 

or in addition to, income production-from timber 

sales. Some of the most frequently given reasons 

were not related to timber production or economics 

but were categorized as lifestyle enhancement 

values. More than 80 percent of these owners 

said : 

I'm proud of it. 

It protects the environment. 

It is satisfying just to own it. 

Birds and animals live in my forest. 

It's like money in the bank. 

Wildlife is important to me. 

1 Like to walk in the woods. 

Me cut firewood from our forest. 

It will help finance my retirement. 

When asked specifically about wildlife, 

78 percent of the respondents had hunted game 

animals, but more had enjoyed the following 

activities: 

Appreciated fall leaf colors. 

Gathered wildflowers, nuts, or berries. 

Watched migratory birds. 

Observed birds and animals, 

Provided food for wild animals. 

Observed flowering plants. 

Forty-eight percent of these owners valued their 

forestland primarily for timber production 

(11 percent) or economic reasons (37 percent). 

More than one-half of them (52 percent) gave 

lifestyle enhancement values as the primary 

reasons. Since this was the case, effective 

change programs must be designed to encompass 

noncommodity lifestyle enhancement goals which are 

clearly unrelated to economics or timber production. Chi-square tests indicated that the 

respondent's age, income, education, retirement 

status, and size of his forestland holdings were 

not related to his primary reason for valuing his 

forestland, but his occupation was related to his 

perceived benefits. 

Independent Variable Chi-square p-value 

Age: < 50, = or > 50 0.938 0.33 

< 60, = or > 60 0.382 0.54 

Income: < $30,000, 

= or > $30,000 0.543 0.46 

Education: college degree, 

no degree 0.963 0.33 

Occupation: farmer, 

businessman 6.313" 0.01 

Retirement: yes, no 1.666 0.20 

Size of forestland ownership: 

< 300 acres, = or > 300 acres 0.087 0.77 

a~ Chi-square of 6.31 with a p-value of 0.01 

indicates nonhomogeneity. 

Those owners whose primary source of income was 

farming gave reasons related to timber production 

or economics, and businessmen gave reasons related 

to lifestyle enhancement values. 

CONCLUSIONS AND QUESTlOSS 

Three conclusions of the study lend credence to 

the use of an interdisciplinary approach combining 

forestry and sociology to improve technology 

transfer to private forestland owners: 

1. Opinion leaders who own nonindustrial 

private forestland can be identified equally well 

by county agents and county foresters. 

2. These opinion leaders can be categorized as 

early adopters. 

3. More than one-half of the opinion leaders 

placed more importance on lifestyle enhancement 

benefits of their forestland than on timber 

productionleconomic benefits. 

This preliminary study has explored the 

applicability of some diffusion of innovations 

research methodology to the nonindustrial private 

forestland owners social system. The findings are 

presumed applicable in rural counties of the South 

Carolina Piedmont, but not necessarily elsewhere. 

Much work remains to be done. Two important 

questions are: 
1. Do the findings apply to other nonindustrial 

private forestland owners (a) who are not living 

on their land? (b) who live in other geographic 

locations? 

2. Do silvicultural practices spread through 

the nonindustrial private forestland owners social 

system in a manner similar to diffusion of 

innovations in other social systems? 

Partial support for this study was provided by 

the McZntire-Stennis Cooperative Forestry Research 

Program. 

LITERATERE CITED 

Muth, Robert Me; Hendee, John C. Technology 

transfer and human behavior. Journal of 

Forestry 78(3):141-144; 1980. 

Rogers, E. M.; Shoemaker, F, F. Communication of 

innovations: a cross-cultural approach. New 

York: The Free Press; 1971, 476 pp. 

Rogers, Everett M, Diffusion of innovations. 3d 

ed. New York: The Free Press; 1983. 453 pp. 

Zaltman, Gerald; Duncan, Robert; Wolbek, Johnny. 

Innovations and organizations. New York: John 

Wiley & Sons; 1973. 212 pp. 
X Conpar1 son of Prof itab~ iity for Agriculturai 

and Forestry Prodcct l on on Southern Margi nal 

AURELlA B, HARRIS 2 

Lana 1s the fundamental product~on resource for 

agriculture and forestry, For the past two 

decaaes the U.S, has been burdened ~7th 

becl ~ni ng agr~cuitural commod~ty prlces, excess 

crop product1 on, and most recently, ~ncreasi ng 

acreage being croppea for agr~ culture, Fedk~w 

et al, (1983) est~mated that there are 2 to 7 

rn~ 7110n acres of crop and pastureland In the 

Southern States of North Carol~na, South 

Carol ~na, Florida, Georg~a, Alabama, 

Miss~ss-ippi, Louisiana, Ar~ansas, Tennessee, and 

Texas wb~ch would produce a greater net return 

from forestry than from ex~sti ng agr? cultural 

crops, Vas~ev~ch estimated that there are 

close to nlne msllion acres of highly erodible 

agricultural low productive cropland in these 

ten Southern States, Gonvert~ng marg~nal 

cropland to forest would reduce excess crop production and Increase agricultural commodity 

prices, thus prov~d~ng a higher rate of return 

on investments to those who remas n in agri - culture, H~gher commodity prlces could also 

reduce the cost of farm crop subs~dy programs, 

Timber 1s unique among marketable commod~t~es 

In that its prlces over the long term have bee^ 

increaslng In relation to the prlces of other 

goods, Adams and Haynes (1980), ID what is probably the best known forest econometric model, 

project a continuat~on of th~s trend of 

increaslng prlces. If the demand for timber 

continues to increase as expected through 2030, 

further real price increases are likely for 

southern timber, This outlook exlst in part 

because of i nadequaxe regeneration of pi ne after 

harvest and loss of forest acres to other land 

uses. 

lSymposium on "Current Topics in Forest 

Research: Contr-i butt ons by Nomen scientist^," 

Nov, 4-6, 19&, Gainesvilfe, FL, 

'~conomi st, USDA Forest Service, Southeastern 

Center for Forest Economics Research, P-0. Box 

12254, Pesearch Triangle Park, NC 27709, 

Abstract, --An analys~s is underway to compare 

returns from crop and pine t~nber production on 

marglnai cropland In 10 Southern States, Marginal, 

h~gkly erodible croplaob has much lower y:elds than 

most other farmland produc~ng the same crops In the 

same regions, tow yields retard earnings, no 

matter what the prsddct price. Much of tkls marglnai cropland may be highly probuct~ve for pjne 

ctilture, 

Not surpr~s?ngfy, we have found very low returns 

from corn, wheat, and soybean production on suck 

la~d, Although the analysis 1s incomplete, we 

belleve that returns from pine culture will be 

higher than that from crops, even when 10-year 

Covservadion Reserve payments are ignored, 

Keywords : Marginal cropland, returns, product ion 

alternatives, crop conversion, 

This paper descrl bes progress In an effort to 

compare the net returns of jnvestment alternattves In agrlculture and forestry for owners 

of southern marg~ nal cropland, The analysis 

1s conf~nded to s~tes w~thin the 10 states on 

wh~ch low agrlculture productiv~ty and high eroslon potent~al, Marg~nal cropland, as used in 

th~s paper, 1s def~ned as land presently in agrlcultural crops that does not gecerate returns 

sufficaent to cover the cost sf product~on and 

that has an erosloo factor of at least 3T (three 

tJnes the So11 Conservat~oc Servace acceptable 

sol l loss to1 erance), 

Marginal cropland in the South is identified by 

using Major Land Resource Areas (MLRA), MLRA's 

are major geographic land resource units that 

are characterized by a particular pattern of soil 

climate, water resources and land uses. In the 

South 30 different MtRAk contain marginal 

cropland, 

Land Use in the South 

In a thorough discussion on southern land use, 

Healy (1985) reported that 56.5 percent of 

southern land is forested. The Coastal Plain 

tends to be pine country, the Piedmont a mixture 

of pines and hardwoods with the upland forest 

consisting of a few local softwood stands, but 

contai ni ng predominantly hardwoods, 

Agri culture , ranked second, occupy i ng 17.6 percent of the total land area of the 12 Southern 

States exarnrned by Healy, By acreage, the 

South" principal crops are soybeans (over 25 

million acres) wheat, corn, hay, cotton, rice, 

and peanuts, The highest value crop is soybeans 

w1t.h tobacco a close second, Healy found that 

grazing is the third most important use of 

southern Sand. Approximately 41 mi 11 ion acres, 

12.5 percent of the South" land are used exclusively or primarily for pasture and rangeland, 

The fourth most important land use category Mealy 

discussed was called the "'built-up area,'hwhich 

accounts for 6 -4 percent of the South" land, 
Flexibility of land use has always been an 

important asset in herica, Nat~onal Resources 

Inventory JNRI) of the Soi l Conservation Service 

(SCS) indicates that between 2907 and 1975 

approximately 80 mt 1 lion acres of land has 

shifted between agriculture and forestry, 

During that period, there was a net loss of 

approximately 30 mi 11 ion acres of forest land 

(Alig 19833, Many acres lost to forestry were 

gained by agriculture as agricullgral prsces 

increased in the 70'sAnalysis of competitive land uses is complicated by the different time patterns sf income 

flows from various uses (Alig 19&), A1 t else 

being equal, landowners may prefer (or require) 

the annual returns of agriculture, to the less 

frequent returns from forestry. Land use comparisons also involve '"expected" net incomes. 

A1 i g rai ses an addi t i ona 1 comp l i cat i on because 

little is presently known about how landowners 

estimate future prices and cost associated with 

alternative uses, In this paper, we present 

expected incomes for agriculture and explain how 

forestry incomes are to be calculated in hopes of 

reducing complications and providing landowners 

and poli cy-makers with relevant information, 

Government Programs 

Recent concern within and outside the USDA has 

focused on consistency of some USDA programs 

designed to influence land use decisions, 

Speci f i cal ly , programs to reduce excess production of agricultural commodities, to support commodi ty pri ces conf 1 i ct i ng effects and i ncome and 

to promote conservation have inconsistent and 

cnflicting effects. 

Commodity price and income support programs are 

designed to improve prices and raise farm income 

(Osteen, 1984), Hi gher , more certai n income 

leads to increased investment in crop produciton, 

including bringing marginal cropland under cultivation. When a commodity program is instituted, 

it is to the land-owner's advantage to maximize 

the use of the area under cultivation. By doing 

so the landowner minimizes the impact of withdrawing a part of the land from production and 

maximizes the acreage base from which payments 

computed. 

If future prices are uncertain, landowners are 

less inclined to commit to long term investments, 

Higher, more stable prices encourage the development of more marginal land, and discourage the 

conversion of cropland to forest. Hence, if 

marginal cropland is erodi ble, some commodity 

programs tend to encourage the use of erodible 

land, whi f e soi l conservation programs hope do 

discourage such use. 

Some research indicates that the price 

increases associated with commodity programs 

benefit as much or more nonparticipants than pasti cipants. Johnson and Short (1983) indicated 

that 70 percent of sndl rect (pr~ ce improvement 1 

benefits of the 1978 corn acreage reduction 

program in selected Southern States were received 

by those who bid not part~cipate in the program, 

Gardner Cl.982) estimates that farm programs 

increased prices received by farmers by 6 percent 

in 2978-79, Participants and nonparticipants 

alike benefit fro^ these price effects, 

Participants also receive di rect payments, but 

they give up income o~ land temporarily idled to 

comply with program requi rement 

Reichelderfer (1984, 1985) studied farms in 

highly erodible areas of the U,S,, including the 

Southern Piedmont, the Sobthern Coastal Plain, 

and the Southern Mississippi Val ley. Erosion was 

measured at 2,800 sample points in 68 countries, 

The character? stics of the operators who managed 

the land at each pol nt were then ta7 lied arid analyzed, One of the major goals of this effort was 

to identify re rat i onships between USDA program 

parti cipat~ on and erosion, The results show that 

those participating only in commodity programs 

had a higher percentage of thei r land eroding at 

greater than 5 tons per acre per year than did 

nonparticipants and those participating in both 

conservation and conmodi ty programs, Nevertheless, she found that participants in the USDA programs show some contribut~sn to soil erosion, 

Reichelderfer (1983) found that 50 to 35 

million acres (41 to 28 percent of the U.S, 

cropland) losing more than 5 tons per acre per 

year to erosion were operated by participants in 

USDA cornrnodtty andlor conservation programs, 

However, 70 to 95 million acres sf all cropland 

eroding at similar rates were operated by those 

who did not participate In USDA programs. USDA 

program participants Farmed 30 to 70 million 

acres in such a way that erosion was at or below 5 

tons per acre per year. 

Conservation Reserve 

The developers of the Conservat i on Reserve that 

is included in the Conservation Title of the 1985 

Farm Bi 17 estimate that over 70 mi l 1 ion acres 

nationally and 5 million in the Southe will be 

eligible for the reserve in SCS capabi tity 

classes six to eight or two to five, These 

classes have an average soil loss greater than 3T 

per acre per year in their present agricultural 

crops (Meal, 1986j, These Figures include 

wetlands as we17 as highly erodible land, The 

program is structured so that conversion from 

agriculture to permanent grasses or forestry wi 1 f 

be gradual, One-sixth of a1 1 land in the reserve 

is targeted to be planted to trees, 

Conservation Titie of the 1985 Farrn Bi? 7 

Clearing for agriculture in the past has been a 

major cause for declining forest acreage, Since 

1960, 6 percent of the nation's forest land has 

been lost to agriculture (Fedkiw ed a1 . , 1983), 

Many of the gained acres by agr~culture have been 

marginal cropland. For one or more physical 

reasons, this land is not as productive as the 

average qua1 i ty farmland, 
For the past 30 years the USDA farm programs 

have encouraged conversion of some agri cu 1 tural 

land to forest. In the mid 1950's the Soil Bank 

Program was initiated with the primary purpose of 

diverting land from the production of farm crops, 

but a1 so to establ i sh conservation practices, 

This program led to the development of numerous 

pine plantations scattered throughout the South. 

Between 1957-1961 nearly 2 million acres of trees 

were planted in the South (klig, Mills and 

Shackleford, 1982), Many of these pine plantations now contains pulpwood, small sawlogs, and 

other forest products, The reserve program 1s 

similar to The Soil Bank except that conservation 

is the major concern of the newer program. 

The 1985 Conservation Reserve Program (CRP) has 

four parts each having its own objective: 

Conservation Reserve: Provide annual rental 

payments for 10 years 

to take out of producti on crop 1 and that has 

the highest erosion 

levels. Also provide 

half of the cost to 

establish a conservation cover on converted land. 

Swampbuster: Discourage conversion 

of addi t i ona 1 wet 1 ands 

to agriculture by 

making landowners that 

do so ineligible for 

many government benefits. 

Sodbuster: Oi scourage the break1 ng 

of new highly erodible 

land into agriculture 

and encourage the use 

of adequate conservation practice if 

crops are planted. 

Conservation Compliance: Encourage widespread 

use of conservation 

practices on highly 

erodible land by tying 

comp 1 i ance to government program benefit s. 

The CRP wi 7 1 attach permanent land use restri cti ons on 45 mi l 1 ion acres over the next 15 

years. Financial incentives are offered to 

encourage landowners to take advantage of alternative production activities. Land qualifies for 

the program if it is susceptible to annual erosion greater than 3T per acre per year. Neither 

land subject to potential wind erosion nor highly 

erodible land not presently being cropped for 

agriculture is eligible for the program. 

percent of cropland in any one county). After 

bids are accepted, the landowner must grow either 

trees or grasses on the bidded land area for 10 

years without harvesting or selling whatever is 

grown on the land, In return, the federal 

government wi 11 pay 50 percent of the cost of 

conversion plus an annual payment for the first 

10 years, The Cross-Compliance program in the 

CRP will penalize landowners that farm highly 

erodi b1 e cropland after 1990 without an approved 

conservation plan by making them ineligible for 

many government programs, This program is an 

example of how the government is trying to 

improve and implement its existing programs, 

Fedkiw et a7, (1983) reported a possible long- 

, run economic gain for owners of marginal cropland 

in the South who convert to lob101 l ly pine (Pinus 

taeda L. ) planations. Conversion to forest crops 

f rorn agriculture could decrease farm surpluses, 

increase the nation's long term timber supplies, 

dampen the expected strong upward trend in softwood timber prices, and provide an economically 

ef f i ci ent and compet i t i ve return on forest 

investment whi le reducing soi 1 erosion and stream 

sedimentation and improving wildlife habitats. 

Investment decisions for land are usually 

constrained by capital limitations, lack of 

relevant information, owner objectives, market 

expectations (short and long term), and future 

technological developments. The investment 

alternatives for margi nal cropland were analyzed 

here according to the profit maximization criterion. Different profit maximization criteria 

are discussed by Hi rshlei fer (1984) and Henderson 

and Quandt (1968). These criteria include unit 

cost, present value of net returns, present value 

of benefits and cost, internal rate of return, 

and pay-off period. In this analysis, the present value of net returns before taxes is used to 

determine the profitability of each production 

venture. 

Agriculture 

In analyzing the profitability of agriculture 

and forestry, it is assumed that only three 

crops, soybeans, corn, and wheat are grown on 

southern margi nal cropland and that only southern 

pine wi ll be grown on converted marginal 

cropland. These crops and tree species were 

selected because they are the most prevalent 

crops and trees grown commerciafly in the South. 

Others (Hardie 1983; Eason and Flinchum 1984, and 

Fedkiw et al, 1983) have in some way compared 

agricultural production to forestry production 

using land rents or returns per acre. Here the 

production of three agricultural crops is compared with to southern pine production on 

southern marginal cropland. The income 

landowners receive from USDA agricultural and 

forestry income and support programs is also considered. 

Landowners wishing to participate are accepted 

in a first come first served voluntary bidding 

system, There is a maximum annual number of 

acres per county accepted into the program (25 
Agricultural Crops 

The per acre yields for each crop are the 

result of the best two out of three years 1982 

to 1985 on the selected MLRA by state from SCS 

crop budget data. The annual national average 

yield for corn is 110 bufacre, but on southern 

marginal cropland the highest average yield for 

the specified period is 80.7 bu [acre. The 

highest annual average yield for soybeans on 

marginal cropland is 27 bufacre in Louisiana compared to the annual national average of 75 

bulacre. The national average annual yield for 

wheat is 70 bulacre, while on marginal cropland 

the top yield is in Mississippi at 41 bulacre. 

The estimated costs per acre for producing 

acre of corn, soybeans, and wheat on southern 

marginal cropland were taken from budget data of 

the SCS of the USDA (Tables 1, 2, and 3). Total 

costs per acre ranged from $77 to $179 for corn; 

$81 to $243 for soybeans, and wheat from $63 to 

$160. These total costs included both variable 

costs and land ownership cost, cost diffentials 

are assumed due to regional land characteristics, 

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

RATE ~YIELD ?RICE TDT COST CROSS #T ST lRWIll 

----------------------------------------------------------____ ru./m $pu. ------- $/VIELO ------- MMAM Sl 3.12 # 119 34 

ARUUSA.5 36.4 t.23 $7 11Z 15 

FLORIDA 36.7 3.24 148 119 -29 

lEOICIA 4 3.11 62 I13 51 

(IISSISSIWI 40.5 3.28 119 133 14 

NORTH UlQfM 17.4 3.10 124 110 -14 

SOUTIICMOLINA I.7 3.11 122 115 -8 

TE~SSEE SB 3.16 9s 120 a 

TEXAS jP.1 3.49 115 1 36 2 1 

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

'BEST TWO WT ff THREE YEARS 

SOURCE: Dcrlved frm unpublished It' prwtd.d by USDA Soil Conservation 

Strvlce, Uashington, IK. 1!U%. 

Total costs (variable cost and land ownership 

cost), yields ( per bushel per acre), and current 

normalized prices data for 1985 were extracted 

from the SCS data files and used to calculated 

net returns (before taxes) for each crop by state 

on MLRA's classified as margi nal southern 

cropland. Established yields were multiplied by 

the current normalized price per crop to 

obtain the gross returns. Total cost was then 

subtracted to get net return before taxes. 

Net returns per acre before taxes for wheat 

varied from -$52 to $75; corn returns per acre 

ranged from $105 to $65; and soybeans the lowest 

of the three crops $-I55 to $25. Unfortunately, 

it was not possible to obtain datz on the amount 

of income support and commodity monies provided 

TABLE 2. AWNUAL AVERAGE NET RETURNS BEFORE TAXES FOR SOYBEANS 

GROWN ON SOUTHERN MRGINAL CROPLAND 

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

STATE aYIELD PRICE TOT COST GROSS RET NET RETURN ............................................................................... BU./ACRE S~BU. --------- $/YIELD --------- 

ALABAMA 21.4 4.98 115 1% - 9 

ARKANSAS 20.4 5.08 108 108 0 

FLORIDA 25.8 5.11 163 132 -41 

LOUISIAW 26.8 5.03 1% 118 -8 

UISSISSIPPI 25.7 5.10 121 131 10 

NQRTH CAROLINA 22.98 5.02 131 103 -28 

WTH CAROLINA 21.19 5.08 131 99 -32 

TENNESSEE 23 5.05 145 1 16 -29 

TEXAS 23.7 4.80 93 % 3 

SOURCE: Derived frm unpublfshed data provided by USOA Soil Conservation 

Service, Washington, DC. 1986. 

TABLE 3. WWAL AVERAGE NET RETURNS BEFORE TAXES FOR CORN 

GROWN ON SOUTHERN MARGINAL CROPLAND 

--------__-___--_-_------------------------------------------------------------ 

STATE aYIELD PRICE TOT COST GROSS RET NET RETURN ___--_--_____-_-___------------------------------------------------------------ BU./ACRE f/BU. -------- $/YIELD ------- 

ARKANSAS 59.8 2.66 123 159 36 

FLORIDA 80.7 2.74 154 221 6 7 

GEORGIA 53.7 2.74 168 147 -21 

~ISSISSIPP~ 60.8 2.88 162 175 13 

NORTHCARdINA 62.5 2.62 147 184 37 

SOUTH CAROLINA 58 ' 2.73 151 158 7 

TENNESSEE 80.2 2.74 164 219 55 

TEXAS 56.7 2.87 112 16 3 5 1 

------------------------------------------------------------------------------- 

a~~~~ NO OUT OF THREE YEARS 

SOURCE: Derived from unpublished data provided by USOA Soil Conservation 

Servtce, Washington, DC. 1986. 

to individual landowners growing crops in the 

specified MLRA's. Plans later are to determine 

cash amounts by state, crop and production 

region for marginal land to see if there is a 

significant difference between the expected 

income and the actual income received. 

Net returns before taxes with average yield and 

normalized prices are shown in Tables 1, 2, and 

3. For example corn grown in Arkansas on MLRA 

1170 with a yield of 54.1 bushels per acre netted 

$17 per acre before taxes at a price of $2.66 per 

bushel. Corn grown in Florida on MLRA 1561 had a 

yield of only 35.9 average bushels per acre and 

priced at $2.74 a bushel netted -$65 per acre. 

To break even or to cover cost the Florida yield 

must be at least 60 bushels per acre at the 

current price. Yields do have a direct relationship to income earned. Since the yields per 

acre for each crop on marginal cropland are far 

below the national average, net returns before 

taxes for the crops in most of the specified 

acres with in each state produce low to negative 

returns per acre. 
Forestry 

A Forest Service analysis of the timber 

situation in the U.S. projects significant 

increases in the demand for southern pine because 

of economic growth and the South's improving 

position relative to the Pacific Northwest. The 

timberland base is expected to continue to 

decrease, and future growth on some land may be 

lower than original ty anticipated (Haynes and 

Adams, 1980). Continued increase in demand with 

a relatively stable supply suggest that real 

softwood prices wi 11 rise over time. 

Historical land use patterns support the 

assumption that the land used for timber growing 

is that left over from most other uses. From 

1952 to 1977, real prices of southern softwood 

stumpage increased from an index value of 57.8 to 

138.9 (1967=100). Despite the real price rise 

for timber and timber products, private nonindust ri a1 timberland holdi ngs decreased from 143 

to 134.1 million acres. In that same time 

period, holdings of forest industries increased 

from 32.1 to 36.2 million acres (Hardie, 1984). 

The Conservation Title of the 1985 Farm Bi 11 provides an incentive to the nonindustrial landowner 

to convert from jagricultural crops on erodible 

land, Vasievich calculated that there are 8.8 

mi l lion acres of highly erodible cropland are 

suitable for growing trees (Table 4). 

Analysis of forestry investments is not yet 

complete. Some cost analysis has been done, but 

other analysis is just underway. Forestry 

returns will be calculated by Timber Mart South's 

production regions for each state for high, 

medium and low quality tree sites. 

Cost Assumption 

Management cost (cost of production) and 

establishment cost are the only cost associated 

with growing pine. The establishment cost is a 

fixed one-t ime expenditure per rotation, whi le 

management cost is the continuing cost of maintaining and managing a pine stand throughout its 

product i on peri od. 

The major expense in establishing pine plantations are site preparation, seeds or seedlings 

and planting. Since the land under investigation 

is presently in crops, site preparation cost are 

assumed to be close to zero. Variables for this 

analysis include total cost, which is the sum of 

conversion cost (cost of transferi ng production 

from crops to trees), establishment cost, management cost, and landownership cost (excludi ng land 

purchasing cost). Vasievich has estimated total 

planting cost of producing pine on highly erodible to be 63 per acre. 

3~npubl ished USDA Forest Service, Southern 

Timber Supply Study, Provided by Dr. J, 

Michael Vasievich, East Lansing, MI. October, 

1986. 

Growth and Yield 

Ttrnber yield at the end of a given cropping 

period or rotation, The annual incremental 

growth depends upon speci es , site condi t i on, 

management practices. Since we are interested 

only in southern pine, it is assumed that all 

owners use the same management practices , and 

thus that yield depends only on site quality. 

The productive capacity of a forested area is 

often expressed in terms of as site index (SI). 

The height of dominant trees at a certain age. 

Loblol ly pine was selected because it wi 11 produce the height yields on highly erodible 

Southern soi 1s. SCS data on soil typelsite and 

site index for marginal cropland in the South 

was averaged for a 25 year rotation. Land with 

low agricultural productivity is not necessari ly 

poor for tree growing, Although thinning schedules could have been calculated using mean annual 

growth, site quality, and typographic region 

thinning possitilities were ignored in the analysis. The estimated average volume for marginal 

highly erodible cropland, according to Vasievich, 

is 108 cubic feet per acre per year. 

Stumpage Price 

Stumpage price is the price paid for trees as 

they stand in the forest. Stumpage prices vary 

considerably with tree quality, and location, but 

these factors were all assumed to be equal for 

each set of calculations. Past and current stumpage prices for timber were taken from Timber Mart 

South (various volumes). 

Government Cost-Sha re Programs 

Several existing federal and state programs 

help offset the cost of starting a forest. The 

two major existing programs are the Forestry 

Incentive Program (FIP) and the CRP. The 

Forestry Incentive Program, admi nistered through 

the Agricultural Stabi 1 ization and Conservation 

Service (ASCS), may reimburse landowners up to 

68% of stand establishment cost not to exceed 

some maximum amount per acre. 

For all eligible landowners who have acceptable 

bids, the CRP pays 50% of establishment cost and 

an annual incentive payment for 10 years in 

exchange for growing permanent cover (trees or 

grass) on the contracted acres. For those who 

participate, stand establishment cost are minimal. The 10 year income support also makes 

growing trees more attractive to some farmers, 

who are concerned about cash flow , but wi 1 ling 

to convert to trees. 

Ca 1 cu 1 at i ng Forestry Returns E 

There are many variables that affect the economics of forestry in contrast to annual crop product ion. Agricultural crops are harvested 

annually or semiannually, but trees are grown for t 

4~ bid. 
much REFERENCES longer periods of time and for uses other 

than timber sales. This study is concerned only 

with income received from tree sales. 

Using the production regions of Timber Mart 

South and adjusting acreage three different net 

returns for each state were computed on the 

basis of site quality. The rotation length is 

to be 25 years. Site qualities are defined as: 

(1) high site - annual mean growth per acre 

of 85 cubic feet or more, 

(2) medium site - annual mean growth per 

acre of 50 to 85 cubic feet, 

(3) low site - annual mean growth per acre 

of 49 cubic feet or less. 

It is also assumed that there will be no opportunity cost occuring for any other land uses 

other the crops presently grown on the land and 

southern pine. For each state and each site type 

from a1 1 previously mentioned data Present Net 

Worth (PNW) for forestry wi 11 be calculated. 

Return Comoari son 

The most appropriate criterion for comparing 

returns from crops and forestry is an annualized 

version of present net worth. 5The recommended 4 

percent real discount rate (i ) can be 

multiplied by the PNW to get net annual equivalent value by state and site quality. The net 

annual equivalent value of revenue due to timber 

sales permits comparison of a series of annual 

crop returns with one future return for each site 

quality from timber. 

Landowners who participate in CRP and convert 

to trees are eligible for an annual incentive 

payment averaging $40 an acre for 10 years. 

Participation; therefore, reduce the burden of 

lost cash flow. For example, net return before 

taxes for corn in North Carolina is $7 per acre, 

net returns for CRP participants is approximately 

$40 per acre for the first 10 years. After cost 

for labor and management are deducted, income per 

acre of agricultural crops is no where near that 

of tree cover under the CRP. 

 our percent is the real discount rate used by 

the Forest Service for evaluating long-term 

investments in resource management which includes 

estimate for long-term measures of the opportunitiy cost of capital in the private sector. 

Adams, Darius and R, W. Haynes. The 1980 

Softwood Timber Assessment Market Model: 

Structure Projections and Poi icy Simu lat i ons 

Forest Science. Monograph 22 (Supplement to 

Industry to Forest Sciences, 26 (3). 62 p. 

1980. 

Alig, Ralph J., Thomas Mi77s and Robert 

Shackelford, Most Soils Bank Plantings in the 

South Have Been Retained; Some Need Follow-up 

Treatments. Southern Forestry 4f 1) : 6 0-6 4. 

February 19%. 

Alig, Ralph J. Impacts of Forest Land conversi on. An Overview. Renewable Resources 

Journal l(4) and 2(1). Spring and Summer 1983 

8-13 pp. 

Alig, Ralph J. Econometric Analysis of the 

Factors Influencing Forest Acreage Trends in 

the Southeast Forest Science 32(1) : 119-134. 

1986. 

Cochrane, Wi 1 lard. The Development of American 

Agricultural Pol icy 1985 and Beyond. 

Proceeding. Historical Bases of Agricultural 

Po1 i cy. Department of Agricultural Economics. 

University of Arizona and Resources for the 

Future. 1984. 466 p, 

Eason, M.A. and Flinchum D.M. A Guide for 

Compari ng Returns from Forestry Investments to 

Annual Crops. Florida Cooperative Sciences. 

University of Florida. Gainesville, FL. July 

1984. 

FedKiw, Johm. et al. U.S. Department of 

Agriculture. Office of budget and Program 

Analysis. Conversion of Southern Cropland to 

Southern Pine Tree Planti ngs : Conversion 

Feasi bi lity Study. Washington, D.C. 1983. 63 

P 

Gardner, B. L. The Governing of Agriculture. 

Lawrence: The Regents Press of Kansas. 1981. 

Hardie, Ian. Comparative Rents for Farmland and 

Timberland in the South. Southern Journal of 

Agricultural Economics 16 (1) 45-54. Dec. 1984. 

Healy, Robert G. Competition for Land in the 

American South. The Conservation Foundation. 

Washington, D.C. 1985. 333 p. 

Henderson, James M. and Richard Quandt. 

Microeconomic Thory. A Mathematical Approach. 

MacGraw-Hill Book Company. NY. 1958. 

Hirshleifer, Jack, Price Theory and Application. 

Third Edition. Prentice-Hall, Inc. Englewood 

Cliffs, N.J. 1984. 

Johnson, James and Sara Short. "Gommodi ty 

Programs: Who has Received the Benefits?" 

Paper presented at 1983 Annual Meeting of the 

American Agriculture Economics Associati on. 
West Lafayette, Ind. Economics research Service 

U.S. Department of Agriculture. August 1983. 

Nea 1 , James. Conservation Reserve Program 

Begins, Forest Farmer. 45 (9) 16-17, July, 

August. 1986. 

Norri s, F.W. Timber Mar-South Highlands, North 

Carol i na. (various volumes). 

Reichelderfer, Katherine ti. "Will Agricultural 

Program Consistency Save More Soi 1. " Journal 

of Soi 1 and Water Conservation. 39 (4) 

Ju ly/August 1984. pp. 229-231. 

Rei chelderfer, Katherine H. Do USDA Farm Program 

Participants Contribute to Soi 1 Erosion? 

AER-532. Economic Research Service. U.S. 

Department of Agriculture. 1985. 

Osteen, Craig. "The Impacts of Farm Policies on 

Soi 1 Erosi on-A Problem Definition Paper." ERS 

Staff Report. Economi cs Research Servi ce. 

U.S. Department of Agriculture. 1984. 
Determinants of Hardwood Lumber Price 1 

Jennifer I.1. Jacobsen and lJilliam G. Luppold 

The erratic movement of hardwood lumber prices 

over the last 15 years has been a source of aggravation to producers and buyers of hardwood lumber (fig. 1). In this paper, we isolate and measure the factors that determine overall hardwood 

lumber price and the price of the predominate domestic hardwood species--oak. By analyzing overall hardwood lumber and oak lumber price, we can 

compare and contrast price formation of hardwood 

lumber in general to price formation of our most 

important species of hardwood lumber. 

Hardwood lumber price, as used in this paper, 

is the average price of more than 30 domestic 

hardwood species, and oak lumber price refers to 

grade No. 1 Common (medium grade) red and white 

oak. Discussion of the determination of these 

prices is presented in five sections. The first 

section discusses theoretical factors influencing 

price and how these principles apply to hardwood 

and oak lumber price formation. This discussion 

is followed by discussions on model development, 

data base, and empirical results. The final 

section presents an analysis of the empirical 

model and conclusions. 

THEORETICAL CONSIDERATIONS 

In most elementary textbooks, price is shown as 

a Function of supply and demand. These relationships usually are shown via linear demand and 

supply curves intersecting at some market price. 

If demand increases relative to supply, then price 

goes up; conversely, when supply increases relative to demand, price goes down. In the real 

world, price determination cannot always be fully 

explained this way because there may be large 

amounts of inventory on hand, or more than one 

demand interacting with a common supply. Such 

is the case of the hardwood lumber market. 

'presented at the Symposium on "Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists," n'ovember 4-6, 1986, Gainesville, FL. 

2~conomist , Princeton, WV: and Economist, Eortheastern Forest Experiment Station, Forest Service, 

U.S. Department of Agriculture, Princeton, WV. 

Abstract.--Increased export activity in the hardwood and oak lumber markets coincided with rising 

prices of these commodities, which also coincided 

with an increase in the overall price level of all 

commodities. To determine the effect that domestic and international demands have on the prices 

of hardwood and oak lumber, relative price models 

were developed to remove the effects of inflation. 

The models indicated that exports to Europe have 

had and will have an influence on hardwood lumber 

price and oak price seems to be more sensitive to 

changes in exports than overall hardwood lumber 

price. The main determinants of hardwood lumber 

and oak lumber prices were found to be domestic 

demand and millstock levels. 

Keywords: Oak, demand, exports. 

As indicated, price is mainly the result of 

supply and demand forces. However, in any given 

year, as much as 20 percent of the hardwood lumber 

produced is held in inventory in the form of millstocks (lumber on hand at sawmills). Furthermore, 

hardwood millstocks can vary by as much as 20 percent from one year to the next. The volatility of 

millstocks results from the yearly differences in 

lumber production versus lumber demand and, therefore, affects hardwood lumber price. 

Domestically produced hardwood lumber is demanded by both domestic and foreign buyers. The domestic market for hardwood lumber is nearly 20 

times the size of the export market. Almost 50 

percent of the lumber demanded domestically is oak. 

Although the export market for hardwood lumber is 

relatively small, the level of exports seems to 

affect lumber prices significantly. Again oak is 

the major exported species accounting for 50 percent of the exports. 

MODEL DEVELOPMENT 

Luppold (1982) developed an equation for nominal 

hardwood lumber price as part of a system of equations depicting hardwood lumber demand, supply, 

and price. The price equation was a multiplicative 

form and was estimated using ordinary least squares 

(OLS) procedures. The specification of Luppold's 

price equation is presented in equation 1 and includes variables representing past lumber price, 

quantity of lumber demanded domestically, quantity 

of lumber exported, and millstocks. 

where bo, bl, b2, b3, and b4 are estimated parameters and: 

P = Current price of hardwood lumber 

EXP = Average price of hardwood lumber over the 

past 3 years 

QD = Quantity of hardwood lumber demanded 

QE = Quantity of hardwood lumber exported 

XS = Level of milistocks 

The weakness in Luppoldfs specification is that 

inflation, exports, and expectations of inflation 

all followed similar paths during the last 15 
years. Therefore, the influence of exports could 

have been over- or underestimated. A real-price 

(inflation adjusted) model or its operational 

proxy, a relative price model, would resolve this 

problem. The difference between relative price 

movement versus nominal (actual) price movement 

can be seen by comparing figures l and 2. The 

models to be presented in this paper are relative 

price models. Since price expectation in the 

hardwood lumber market tends to be related to inflationary expectations, the current specification 

excludes past lumber prices. 

Actual Price lndex of Oak Lumber 

--- Actual Price index of Hardwood Lumber 

o--*-*.l.l'l.l.*.l*l.'.l 

60 62 64 66 68 70 72 74 76 78 80 

YEAR 

Figure 1.--Indexes of actual oak and hardwood lumber prices. 

Relative Price lndex of Oak Lumber 

--- Relative Price Index of Hardwood Lumber 

50t~*~~~1~*

60 62 64 66 68 70 72 74 76 78 80 

YEAR 

Figure 2.--Indexes of relative prices of oak and hardwood lumber (relative 

to the price index for all commodities). 
Another difference between the specification of 

the current price equations and Luppold's (1982) 

specification is that European and nun-European 

exports are represented by separate variables. 

This allows us to separate the effects of European 

exports from those of exports in general and to 

test whether European exports affect domestic lumber price differently from non-European exports. 

The specific definition of the variable to be included in the hardwood lumber and oak lumber relative price equations is outlined in Table I. 

DATA BASE 

The data base used in the estimation of the 

hardwood lumber price equations and the oak lumber price equation extended from 1960 through 

1980. All data were obtained or derived from 

secondary sources. 

Indexes for hardwood lumber price, oak lumber 

price, and the producer price index of all commodities were obtained from U.S. Department of 

Labor (1961-80) Producer Price and Price Indexes. 

Since no aggregate oak price representing all 

grades and species was available for the study 

period, the price of No. 1 Common red oak was 

used as the dependent variable in the oak price 

equation. 

Quantities of hardwood lumber and oak lumber 

exported were obtained from U.S. Exports, Schedule 

B. Commodity by Country (U.S. Department of Commerce 1961-79). Millstock and lumber production 

figures were obtained from U.S. Department of 

Commerce (1961-80) Current Industrial Reports: 

Lumber Production and Mill Stocks. Quantity of 

hardwood lumber demanded domestically was derived 

by subtracting exports and changes in millstocks 

from production figures. 

The quantity of oak lumber demanded and the 

millstocks of oak lumber were estimated by multiplying the proportion of oak lumber produced by 

domestic quantity demanded and by millstocks, respectively. The proportion of oak lumber produced 

was calculated by dividing oak lumber production 

by total hardwood lumber production. 

MODEL ESTI?&TIOK 

The statistically estimated parameters of the 

hardwood lumber and oak lumber price equations are 

presented in Table 2. Both equations fitted the 

data relatively well, as indicated by the Il2's 

and the "t" statistics. The nonintercept variables representing exports to Europe, millstocks, 

and domestic demand were significant at the 13.10 

Level or better. The variable representing nonEuropean exports was insignificant in both equations. Although the Durbin Watson (DW) statistics 

are reported for both equations, they are not 

strictly interpretable because of the inclusion 

of a lagged dependent variable in the model 

specification. 

The price equations were estimated in multiplicative form by taking the natural logarithms of 

all variables before estimating the relationships 

through OLS procedures. Because the equations are 

in multiplicative form, the resulting parameters 

are measurements of the percentage change in price 

resulting from a 1-percent change in the respective independent variable. Such measurements are 

termed flexibilities (Tomek and Robinson 1972). 

Because the non-European export coefficient is 

not statistically significant, future use of the 

term "price flexibility of export" refers to exports to Western Europe. 

The estimated price flexibilities indicate that 

oak lumber price is affected by changes in domestic demand, millstocks, and exDorts to a greater 

degree than hardwood lumber price. This finding 

may explain why oak price tended to fluctuate 

more than hardwood lumber price even during the 

pre-1973 period when exports were a minor part of 

the market. The increased divergence between oak 

lumber and hardwood lumber price fluctuations 

since 1973 (figs. 1 and 2) probably results because (1) changes in oak exports affect oak price 

more than changes in hardwood exports affect hardwood price, and (2) changes in oak exports to 

Europe have been greater than changes in total 

hardwood lumber exports to Europe. 

Table 1.--Dependent variables for the hardwood lumber and oak lumber price equations 

Variabl e Actual variable used in 

hardwood lumber price model 

Actual variable used in 

oak lumber price model 

Quantity demanded 

domestically 

Exports to 

Western Europe 

Exports outside of 

Western Europe 

Millstocks 

(inventories) 

Quantity of hardwood lumber domestically Quantity of hardwood lumber domestically 

consumed in current year consumed multiplied by the proportion of 

oak lumber produced 

Quantity of hardwood lumber exported to Quantity of oak lumber exported to 

Western European countries Western European countries 

Quantity of hardwood lumber exported to Quantity of oak lumber exported to other 

other than Western European countries than Western European countries 

Average level of millstocks of hardwood Average level of millstocks of hardwood 

lumber at end of current year and past lumber multiplied by the proportion of 

year oak lumber produced in current year and 

past year 
Table 2.--Ordinary least squares estimates for 

hardwood and oak lumber price equations 

(t statistics in parentheses) 

Item Hardwood Oak 

lumber lumber 

Intercept 

Quantity demanded 

domestically 

Exports to 

Western Europe 

Exports outside of 

Western Europe 

Millstocks 

.I. J. 4 rr ,, zc = Significant at the 0.01 level. -7 J- 

= Significant at the 0.05 level. 

= Significant at the 0.10 level. 

Another fact demonstrated by the estimated price 

flexibilities is that a 1-percent change in domestic demand or millstocks has a much larger influence on hardwood lumber and oak lumber prices than 

a I-percent change in exports. In the case of oak 

lumber price, exports would have to increase by 

19.5 percent to have the same impact as a 1-percent 

change in domestic demand and by 12.6 percent to 

have the same impact as a 1-percent change in millstocks. However, to fully understand the causes 

of price variation, the relative impacts of changes 

in the independent variables that are represented 

by the flexibilities must be coupled with the actual changes in these independent variables. 

From 1972-80, yearly changes in domestic demand 

averaged 6 percent, millstocks averaged 12 percent, and exports averaged 50 percent. Analysis 

based on these 1972-80 average yearly changes 

shows that changes in domestic demand affected oak 

lumber price 2.3 times as much as changes in exports, and changes in millstocks affected oak lumber price 3 times as much as changes in exports. 

Similarly, changes in domestic demand affected 

hardwood lumber price 5.2 times as much as changes 

in exports, and changes in millstocks affected 

price 10.1 times as much as changes in exports. 

In the late 19701s, when domestic demand was increasing and millstocks were decreasing, increased 

levels of exports helped push lumber prices up 

even further. On the other hand, during 1979 and 

1980, when domestic demand was decreasing and 

inventories were increasing, increases in exports 

helped moderate the drops in hardwood lumber and 

oak lumber prices. However, since 1980, changes 

in export demand have moderated; therefore, the 

effect of exports on hardwood lumber prices has 

become almost nonexiscent. 

The ~rimary factors influencing hardwood lumber 

and oak lumber prices are price expectations, 

domestic demand, exports, and lmel of millstotks. 

The results of model estimation indicate that the 

coefficients associated with these variables are 

higher in the oak lumber equation than in the 

overall hardwood lumber equation. This explains 

why there is a greater variation in oak lumber 

price than in overall hardwood lumber ?rice. The 

results also indicate that while changes in domestic demand have the greatest relative influence 

on hardwood lumber and oak ltlmber price, Large 

swings in level of exports over the last several 

years have contributed to the large swings in 

price. 

LTTERATURE CITED 

Luppold, idilliam G. An econometric model of the 

hardwood lumber market. Res. Pap. NE-513. 

Broomall, PA: U.S. Department of Agriculture, 

Forest Service, Northeastern Forest Experiment 

Station; 1982. 15 p. 

Tomek, William G.; Robinson, Kenneth JA- Agricultural product prices. Tthaca, NY: Cornell 

IJniversity Press; 1972. 378 p. 

1J.S. Department of Commerce, Bureau of the Census. 

Current industrial reports: lumber production 

and mill stocks. Washington, DC: U.S. Department 

of Commerce; 1961-1980. 

U.S. Department of Commerce, Bureau of the Census. 

U.S. exports, Schedule B. comr,lodity by country. 

Washington, DC: U.S. Department of Commerce; 

1961-1979. 

U.S. Department of Labor, Bureau of Labor Statistics. Producer prices and price indexes. Washington, DC: U.S. Department of Labor, 1961-1980. 
An Economic and Ecological Perspective on the 

Renewability of Forest Ecosystems 1 

Jud it h ax we 1 l2 

Man and forests have co-evolved in response to 

each other. Historically, the onus was on man to 

adapt by devising types of shelter and methods of 

hunting and gathering which increased the probability of survival. Only very recently, from the 

standpoint of evolutionary time, have forests 

become the adapters. This change can be attributed to the emergence of the modern economic 

state with the primacy it places on human goals 

and technical advance as a means for overcoming 

resource scarcity. Forests are primarily viewed 

as a sys tem for produc ing market-oriented outputs, 

such as timber, as opposed to such nonmonetary 

products as recreation and aesthetics. Furthermore, the failure of market prices to reflect the 

values associated with the assimilative and regenerative capacities of forest ecosys tems have 

resulted in the choice of "economic" management 

techniques which ignore impacts on the long-term 

renewability of forest ecosystems. 

RECENT TRENDS IN FORESTRY: SOME OBSERVATIONS 

Population pressure, fuelwood demand, and the 

willingness of governments to liquidate natural 

resources for foreign exchange have resulted in a 

loss of two-thirds of Southeast Asian rainforests 

and one-half of Africa's tropical forests, while 

more than one-third of Amazonian forests have been 

cut over (Spears and Ayensu, 1985). Accelerating 

rates of tropical deforestation have been one 

factor leading to several alarming projections of 

species extinctions (Myers, 1979; Ehrlich and 

Ehrlich, 1981 ; Soule and Wilcox, 1980). However, 

even though these ecosystems are extraordinarily 

vulnerable, little is known about the correlation 

between the disappearance of tropical fores ts and 

species extinction (Harrington and Fisher, 1982). 

In contrast, the area of temperate forests has 

remained relatively stable in recent years; standing timber inventories have actually increased in 

the U.S, However, the quality of regional forest 

resources in the U.S. has been questioned (Birch, 

1986; McLintock, 1983; Marty, 1983). Also, while 

there is a general commitment to reforestation in 

'presented at the Symposium on "Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists." 

'~ssistant Professor, Division of Forestry, 

School of Natural Resources, The Ohio State Univers ity , Columbus, OH. 

Abstract .--The role of economic factors in forest 

management is evaluated from the standpoint of 

ecological considerations. An alternative 

approach, which recognizes a forest as a technology in itself, is used to discuss the role of 

induced technical and institutional innovation in 

the development and adopt ion of management tec hniques which are more consistent with ecological 

processes. 

Keywords: forest management economics, technical 

choice. 

many countries in the temperate zone, this has 

frequently meant the establishment of monocultures 

of Pinus sp~. resulting in declines in species 

diversity similar to those associated with agriculture. For mixed temperate hardwood forests , logging practices have negatively impacted natural 

regeneration causing soil erosion and stream 

siltation. Selection cutting (high grading) of 

the hardwood forests in the eastern U.S., by 

concentrating on the harvest of commercially 

preferred species and log sizes, has resulted in 

increasing acreages of poor quality and largely 

suppressed individuals of less desired species 

(Barrett, 1980; Seymour, Hannah, et al, 1986). 

McConnell (1980) suggests that high grading has 

degraded loblolly pine in the eastern U.S. Ledig 

(1986) discusses the correlation between the 

dysgenic effect of certain forestry practices on 

genetic resources and the potential for diminished 

resilience of future forests. 

Of all the natural resources examined by Manthy 

(1978), wood was the only commodity that has experienced a continuous long-term upward trend in 

its real price in the U.S. Such increases in real 

price are considered to be indicative of "economic" scarcity. Starting in 1979, however, the real 

prices for standing timber and finished products 

plunged and have since become so volatile as to be 

useless in determining scarcity. Brown (1981) 

argues that a preferred measure of resource scarcity includes some concept of carrying capacity 

such as the ratio of production to population and 

points out that the world production of wood on a 

per capita basis actually declined over the period 

1964 to 1980. However, production is a function 

of demand and the availability of substitutes and, 

as such, is a very imprecise measure of scarcity, 

Hannon (1986) contends that there exist finite 

limits to the capacity of technical change to 

mitigate the effects of increasing resource scarcity. Evidence of this limit is the substitution 

of low-wage for high-wage labor and low-return 

capital for high-return capital as already 

witnessed in the shift of extractive resource 

industries, such as forestry, from developed to 

developing countries. If we also account for the 

effects of resource use on the environment, it 

becomes apparent that resource scarcity reduces 

both long-term material wealth and environmental 

quality. We are increasingly confronted with the 

difficult choice between environmental quality and 

commerc ial goods and services. However, where 

consumers and producers are geographically separated, it is in the consumers' best interest to 
avoid this choice. This factor, in part, has led 

to a ban on log exports by several southeast Asian 

nations. 

The scarcity of wood in some regions and for 

particular end-uses has resulted in an increasing 

trend to plantation forestry. Forestry is undergoing a transition similar to that experienced by 

agriculture. Some believe that agriculture, by 

habitat modification, is threatening the very 

basis of its resounding success-the availability 

of natural environments which provide an inventory 

of new genetic ~trains.~ However, ex situ preservation of genetic capital for agricultural crops 

far exceeds that for tree species, and given the 

difficulty in maintaining genetic integrity in 

storage, in situ preservation is preferred (Ledig, 

1986). Jasso (1970) has documented the effects of 

the expansion of agriculture on the genetic diversity of several species of as remnant stands 

are increasingly confined to poor sites. 

In the case of northern hardwood forests, it is 

not the lack of genetic capital in a regional 

sense that is at issue, but the lack of productive 

use of this capital in individual management decisions. In the northern U,S., plantation forestry 

has the potential to increase both genetic and 

species diversity and to create a more diverse 

regional habitat, as did agriculture initially. 

However, the correlation between the supply of 

genetic capital and the extent of diverse, natural 

forests must be considered whenever habitat is 

modified or converted. 

Duerr (1986) argues that while forests are 

biologically renewable, what really counts is 

their social renewability, noting that the ragged 

condition of many nonindustrial private timber 

holdings is a social decision. However, our 

ability to increase the efficiency of extraction 

and to develop highly productive monocul tures in 

response to economic factors has far outstripped 

the ability of our social and political institutions to respond to resultant negative impacts on 

environmental quality. This is due to missing 

markets for many forest ecosystem benefits and the 

absence of data on ecosystem processes. 

My own research is directed toward explaining 

technical choice in the management of mixed 

hardwood forests of the eastern U.S. in terms of 

the absence of markets for certain forest outputs 

and to clarify the role of political and social 

institutions in influencing the development and 

adoption of techniques which account for environmental impacts. This paper explores some of the 

3~t is important to distinguish between species 

and genetic diversity, Tree improvement programs 

can provide for more genetic diversity in 

monocultures than can be obtained in nature where 

parents are widely separated and the radius of 

seed dispersal is relatively limited. The concern 

here is for the loss of genetic capital as habitat 

is converted to monoculture production not the 

lack of species diversity in the monoculture 

itself, 

the economic and ecological issues which are relevant to the proposed research. 

GOWRCIAL VALUES AND THE VALUE OF FOREST 

ECOSYSTEMS 

The fact that nature's values are seldom economic values is exemplified by the rapid invasion 

of abandoned famland by weedy, shade intolerants. 

And, even though trees provide the major commercial value for forests, characteristics such as 

imobility, low dispersibility, small number of 

progeny, and long life spans cause trees to be 

more susceptible to habitat modification, pollutants and pests than such generalist species as 

annual plants* 

The dichotomy of views is apparent in what many 

ecologists and economists measure to determine the 

productivity and stability of natural ecosystems. 

For ecologists the focus is on ecosystem resilience and the production of biomass, as opposed to 

economists' preoccupation with the sustained yield 

of a particular species or log size. The latter 

concept is epitomized in plantation forestry which 

maintains an ecosystem in its most highly productive phase (albeit a phase characterized by very 

low species diversity) through reliance on fertilizers, pesticides, and energy inputs. 

The nature of constraints used also shows fundamental differences between the two disciplines 

Ecology emphasizes the conservation laws of 

energy, carrying capacity , and the deteminat ion 

of a stress threshold for ecosystem resiliency. 

Economics rarely emphasizes physical constraints, 

except when signaled by prices, concentrating on 

f inanc ial constraints such as interest rates and 

institutional constraints on investment strategy. 

The temporal and spatial treatment of these 

constraints also differs. For temperate hardwood 

forests, a time frame of 300 or 400 years is 

consistent with successional processes well in 

excess of human planning horizons. The result is 

that the high discount rates used by private 

owners to assure short-term profit maximization 

can cause overexploitation and eventual exhaustion 

of renewable resources such as forests (Clark, 

f 973). Even if the discount rate were zero, 

meaning that future dollars equal current dollars, 

the relatively short lifespan of humans will still 

result, for many owners, in forest management 

practices aimed at keeping a forest in its shortterm productive phase even if this undermines 

long-term health and productivity. 

In ecological analysis the choice of boundary 

(spatial) conditions will focus on the area within 

which material and energy flows take place and are 

detemined by whether the analysis concerns a 

species or some higher order process. In economics, borders tend to be political or managerial or 

may be defined by an economic relationship such as 

a trade pattern. 

One of the major failings of economics, from the 

standpoint of ecologists, is its preoccupation 

with human values and the underlying premise that 
monetary units can be used to value the non-monetary aspects of natural resources. The observed 

inc reas ing dependence of man-made ecosys terns on 

energy inputs led to the study of energy flows in 

natural systems, with one objective being to draw 

attention to the finite limits to development 

imposed by energy but not made apparent by economic measures. Lave (1986) contends that the 

major difficulty in estimating the benefits and 

costs of changes in environmental quality lies in 

the quantification of these effects in physical 

terms rather than in evaluation via monetary 

reductionism which tends to divert attention away 

from the important issues. However, do energy 

units do a better job? 

ECONOMICS AND ECOLOGY : THE INTERFACE 

In spite of obvious differences, there is enough 

common ground between the two disc iplines to 

support a comb ined economic and eco log ic parad igm 

for forest management. The short-sightedness of 

traditional human "use" values, which change too 

unpredictably over time to be of use in evaluating 

long-term returns to forest management (such as 

lumber prices and timber utilization standards), 

has resulted in a proliferation of new resource 

value concepts . Economics take the longer 

view. In particular, option value, quasi-op t ion 

value, and bequest value refer to concern over the 

availability of future uses; the loss of future 

valuable uses, yet unknown, to habitat mod if ication; and to the altruistic desire to preserve 

availability for future generations, respectively. 

These are examples of economists' attempts to find 

alternative measures of the benefits of natural 

ecosystems and to incorporate some metric of risk 

when there exists a potential for catastrophic 

costs when our current state of knowledge regarding the response of ecosystems to stress is 

limited. 

In practice, the measurement of these value concepts has remained difficult and largely limited 

to the valuation of individual species and aesthetic and recreation benefits which directly benefit 

humans. Ehrlich and Ehrlich (1981) differentiate 

between the direct and indirect benefits of species preservation, defining the latter to consist 

of the largely free services of ecosystems and the 

processes which support them. These include the 

maintenance of atmospheric and aquatic quality, 

the amelioration and control of climate, flood 

control, the maintenance of a genetic library, and 

the supportive role of food webs and nutrient 

eyc 1 ing . The overall deficiencies in the data regarding 

ecosystem benefits led S.V. Ciriacy-Wantrup (1968) 

to suggest the Safe Minimum Standard Approach 

(SHS) which is defined as the minimum level of 

preservation which ensures survival. This 

approach has been promoted by Bishop (1978) to 

argue for the preservation of species . While 

avoiding quantification of benefits, Bishop takes 

the continued discovery of valuable uses for 

species as an indication of their high and rising 

value* Given that the survival of species is 

dependent on preservation of its habitat, and that 

this habitat is dependent on the ability of its 

ecosystem( s) to withstand perturbation, suggests 

the usefulness of the SMS approach in arguing for 

the preservation of whole ecosystems or even 

larger areas. 

Norton's 11986) concept of contributory value 

would assign value to species, not due to their 

direct value to humans, but according to their 

role in maintaining and accentuating ecosystem 

processes which provide indirect benefits to man. 

Contributory value recognizes both the long time 

frames involved in many ecological processes and 

the synergism which can result from the interaction of two or more species creating benefits of 

which none is individually capable. Though 

empirically elusive, this value concept does 

provide a useful focus for conceptualizing how 

forest ecosystems might be evaluated. 

Before evaluation can be achieved, some method 

needs to be devised for monitoring the integrity 

of forested landscapes over time. The concept of 

total diversity, developed by Whittaker (1 960) and 

MacArthur (1965) and extended by Norton (forthcoming), offers a more simple spatial framework 

for evaluating economic and ecologic implications 

of the diversity-stability hypothesis. Norton 

argues that it is total diversity, not with-in 

habitat diversity, that correlates with stability. 

mereas with-in habitat stability refers to the 

number of species and frequency and complexity of 

interactions within a closed ecosystem, total 

diversity is solely a function of the total number 

of species in a given geographic area that consists of multiple ecosystems in various successional stages. 

As such, the concept of total diversity 

citl~ recognizes the importance of underlying 

ecosystem processes by assuming that these processes and/or interdependencies are the result of 

non-random organization over evolutionary time. 

Stability is positively related to species count 

for a geographic area; the more numerous and 

varied are invading species , the more rapidly and 

fully will systems develop defenses against sixniinvasions following future disturbances. Systems which evolve in an environment of high total 

diversity also exhibit more complex spec ializations and interdependencies. This view is consistent with the observed changes in diversity 

within an ecosystem due to successional processes 

and explains the stability of less diverse, mature 

ecosystems such as the redwood forests. 

The total diversity-s tability correlation also 

explains the fragility of very diverse sys tems 

such as tropical forests. The substantial total 

diversity of the tropics meant that individual 

ecosystems had to develop mechanisms to withstand 

the intense, albeit normal, competition or else 

remain unstable. The effectiveness of these 

systems in dampening out "standard" disturbances 

actually increases susceptibility to new, more 

intense or more pervasive disturbances. Thus, 

greater local stability may result in diminished 

global stability. 
For northern mixed hardwood forests, which also 

exhibit a high degree of ecosystem diversity, this 

may mean that forest management practices which 

continually diverge from natural successional 

processes, even if with-in habitat diversity is 

increased, may not produce greater stability. 

This also does not suggest that management should 

be directed at minimizing perturbance s. In 

his study of forest community development in 

Wiscons in, Loucks (1 970) observed that periodic 

disturbance resulted in alternating high productivity phases with high diversity phases and 

concluded that the ability of a forest ecosystem 

to rejuvenate itself is dependent on the natural 

tendency to alternate between the two phases. 

As a forest economist, I am not able to evaluate 

the usefulness of the total diversity concept for 

monitoring the effects of forest management 

practices , pollution and natural disturbances on 

mixed hardwood forests. However, it does seem to 

square with observations. In particular, the 

concept of total diversity provides a more satisfying answer to the question, "What is forest 

productivity?" by refuting the traditional notion 

that practices that increase diversity enhance 

stability and that local stability is concomitant 

with global instability. 

THE ROLE OF INDUCED INNOVATION AM) INSTITUTIONAL 

CHANGE 

Given that diverse forest ecosystems provide 

substantial benefits to humans, it still remains 

that these benefits are difficult to quantify 

relative to those resulting from highly productive 

monocultures. The fact that many silviculturists 

agree that historic management practices in northern hardwood forests have negatively impacted 

productivity, even when the traditional "preferred 

spec ies/log size" measure of productivity is used 

provides a strong basis for considering alternative management techniques. However, the absence 

of a market for most benefits from forests indicates that the development and adoption of appropriate techniques will require institutional 

innovation. 

Binswanger , Ruttan and others ( 1986) have 

clearly shown that technological change is 

sensitive to economic factors such as input and 

product prices. Ruttan (1971) and Runge (1986) 

argue that the absence of markets, for both the 

assimilative capacities and the environmental 

amenities of ecosystems, has resulted in their 

overuse or abuse, leading to a demand for an 

institutional mechanism, such as legislation, to 

ameliorate negative impacts. This explains the 

rap id increase in environmental agenc ies and regulations over the past 15 years. 

This high and rising demand for environmental 

quality is largely limited to upper income countries such as the U.S., where per capita consumption of most forest products has declined since 

the turn of the century (Duerr, 1986) as has the 

conversion of forest land to agricultural uses. 

However, who can blame the poorer countries for 

the low value placed on environmental quality when 

the primary concern is sustenance? The solution 

to declining environmental quality in less developed countries is likely to require both an increase in and a redistribution of income. 

In the U.S., the environmental risk associated 

with the degradation of forest ecosystems is 

likely to be less susceptible to control through 

existing legal and regulatory institutions, due to 

some of the characteristics discussed by Page 

(1978) and adapted here to consider forests. 

First, while there exists a potential for catastrophic loss (that is, a forest ecosystem is 

stressed beyond some threshold and collapses, 

thereby imposing high costs to society in terms of 

altered climatic patterns or loss of potentially 

valuable genetic strains) , the probability of such 

a catastrophe is very low. Secondly, most of the 

current environmental legislation is geared to 

address immediate, acute and visible problems, 

while the decline in a forest ecosystem may extend 

over so many years that changes are imperceptible 

and even masked by other factors. These two characteristics, combined with our ignorance concerning the interactive mechanisms both in forests and 

between pollutants, disease and pests, make it 

very difficult to impose corrective measures. 

However, the fourth characteristic , the irreversibility of an ecosystem collapse, makes public 

action necessary. Irreversibility is defined by 

both economics and time. Once a stress threshold 

has been crossed ecosystem decline becomes irreversible due to either the long time required for 

rejuvenation or prohibitive economic costs. Until 

we recognize the asymmetry which exists between 

the very modest benefits to individual owners who 

use dysgenic forest practices and the potential 

for very high societal costs, we will continue to 

underinves t in the development of new techno log ical and institutional innovations which will result in the management of forests which is more 

consistent with ecosystem processes. 

Fifth, our traditional definitions of forest 

productivity fail to recognize that a forest 

ecosys tem and its subcomponents are technologies 

in themselves. These "ecote~hnolo~ies" (Jorgensen 

and Mitsch, forthcoming) offer strategies for 

enhancing the productivity of both natural and 

man-made systems by management (manipulation) of 

species or higher order processes within an 

ecosystem. Examples include the management of 

forests to provide: 1) in situ gene banks which 

protect both genetic capital and the site specific 

characteristics which are the inputs in the production of this capital; 2) forest islands which 

are repositories of locally adapted species for 

colonization when adjacent land is abandoned; 3) 

forest islands and corridors which serve as oases 

and passageways for migratory animals; and, 4) 

forest/wetland and complexes to control acid mine 

seepage or other point source pollutants. 

Sixth, the common property nature of many of the 

outputs of these ecotechnologies indicates that 

government or other public institutions must be i 

involved in both the development and the adoption 

of these ecotechnologies. We have long been aware 

of the disincentive to the development of a new 
technology that cannot be embodied in a product 

that has a market value or when the benefits of an 

innovation are rapidly diffused, as in biotechnologies such as high yielding crop varieties. This 

resulted in an institutional innovation, in the 

form of government and other publicly funded research institutions, that provides incentives to 

innovators through direct compensation. The major 

difference, then, between ecotechnologies and most 

biotechnologies produced in public institutions is 

that the latter have relatively well-defined markets. However, while ecotechnologies may provide 

substantial benefits to society, the individual 

consumer would be unwilling to pay for a good or 

service from which other users cannot be excluded. 

Therefore, public agencies will also be instrumental either in the direct utilization of these 

ecotechnologies or in providing incentives to 

individual landowners. 

All of these characteristics, I believe, indicate a diminished capacity to provide a timely 

response to concerns over the renewability of 

forests. Given the probability of ecosystem 

collapse, albeit small, and the increase in types 

and intensities of disturbances to which our 

forests are subjected, I do not think that we can 

rely on the usual endogenous pressures which 

induce technical and institutional change in 

response to typical problems of environmental 

quality. However, the theory of induced innovation does provide a basis for determining appropriate responses. In particular, we need to 

examine how the specific environmental benefits 

provided by forests are impacted by forest 

management techniques, and to assess the effic iency and equity of more environmentally benign 

techniques. We need to do this even though 

standing inventories are high and the real prices 

for many forest products remain low because these 

measures do not adequately reflect the value of 

many of the indirect benefits provided by forest 

which are negatively impacted by management 

practices. 

Birch, Thomas W. Forest inventory and analysis in 

the north; with emphasis on the hardwood resource. U.S. Department of Agriculture, Forest 

Service, Northeastern Forest Experiment Station, 

Bromall, PA: 1986. Unpublished research. 

Bishop, Richard. Endangered species uncertainty: 

the economics of a Safe Minimum Standard. American Journal of Agricultural Economics 60 (1 ) : 

10-18; 1978. 

Brown, Lester R. Building a sustainable society. 

New York: Norton publishing Co. 1981. 

Ciriacy-Wantrup, S.V. Resource conservation: economics and politics. Berkeley and Los Angeles: 

University of California, Division of Agricultural Sciences. 1968. 

Clark, Colin W. The economics of overexploitstion. Science 181 :630-634; 1973. 

Duerr, William, A. Forestry's upheaval. Journal 

of Forestry 84(1) :20-26. 1986. 

Ehrlich, Paul and Anne Ehrlich. Extinction: the 

causes and consequences of the disappearance of 

species . New York: Random House. 1981. 

Hannon, Bruce. Foreword. In: Hall, C.A.S., C.J. 

Cleveland and R. Kaufman. Energy and resource 

quality: the ecology of the economic process. 

New York : John Wiley & Sons, Inc . 1986. 

Harrington, Winston and Anthony C. Fisher. 

~ndan~ered' species. In: Portney , P .R., ed. 

Current issues in natural resource policy. 

Baltimore: Resources for the Future, The John 

Hopkins University Press. 1982. 

Jorgensen, Sven E. and William J. Mitsch. Ecological engineering : an introduction to ecotechnology. Forthcoming. 

Lave, Lester B. The cost of abating sulphur, 

nitrogen and ozone air pollutants. American 

Journal of Agricultural Economics 68(2) :473-78. 

1986. 

ACKNOWLEDGEMENT 

The author wishes to thank Bob Vertrees, Gordon 

Gatherum, and Amy Scherzer for their very helpful 

comments and suggestions. This research is 

supported by an Ohio State University Seed Grant. 

LITERPlTURE CITED 

Barrett, J.W. The northeastern region. In: 

Barrett, John W., ed. Regional Silviculture of 

the United States. New York: Wiley-Interscience. 1980. 

Binswanger, Hans P., Vernon W. Ruttan, and others. 

Induced innovation: technology, institutions, 

and development. 2d ed. Baltimore. The John 

Hopkins University Press. 1986. 

Ledig, F. Thomas. Conservation strategies for 

forest gene resources. Forest Ecology and 

Management 14(1)77-90. 1986. 

Loucks, Orie. Evolution of diversity, efficiency, 

and community stability. American Zoologist 

lO(1) :23-24. 1970. 

MacArthur, Robert H. Patterns of species diversity. Biological Review 40(4) :510-33. 1965. 

Manthy, R.S. Natural resource commodities: a 

century of statistics. Baltimore: The John 

Hopkins University Press. 1978. 

Marty , Robert. Retargeting public forestry 

assistance programs in the north. In: Royer, 

J.P. and Risbridt, C.D., eds. Nonindustrial 

private forests: a review of economic and policy 

studies. Durham, NC: Duke University, School 

of Forestry and Environmental Studies. 1983. 
McLintock, Thomas F- The resource: nationwide 

perspective. In: America's hardwood forestsopportunities unlimited - Proceedings , Society 

of American Foresters, 

Myers, &man. The sinking ark: a new look at the 

problem of disappearing species. New York: 

Perga~non Press. 1979 

Norton, Bryan 6. On the inherent danger of undervaluing species. In: Norton, Bryan G, edI The 

 reservation of species : the value of biological 

diversity, Princeton. Princeton University 

Press. 1986, 

Norton, Bryan 6. The spice of life. Forthcoming. 

Page, Talbot. A generic view of toxic chemicals 

and similar risks. Ecology Law Quarterly 

7(2) :207-44. 1978. 

Runge, Carlis le Ford. Induced innovation in 

agriculture and environmental quality. Staff 

Paper P86-18, Department of Agricultural and 

Applied Economics, University of Minnesota. 

1986. 

Ruttan, Vernon W. Technology and the environment. 

Presidential Address. American Journal of 

Agricultural Economics 53(5) :707-17. 1971. 

Seymour, R.S., P.R. Hannah, J.R. Grace and D.A. 

Harquis. Silviculture: the next 30 years, the 

past 30 years. Part IV. The northeast. 

Journal of Forestry. 84(7) :31-3%. 1986. 

Soule, Michael E. and Bruce A. Wilcox. Conservat ion biology : an evolut ionary-ecological perspective. Sunderland, MA: Sinauer Associates, 

Inc. 1980. 

Spears, John and Edward S. Ayensu- Resources, 

development, and the new century: forestry. In: 

Repetto, Robert. ed. The global possible. New 

Haven: Yale University Press. 1985. 

Whittaker, R.H. The vegetation of the Siskiyou 

Mountains, Oregon and California. Ecological 

Monographs 30(3). 1960. 
Forestry Research Eva1 uation: Why and HOW' 

Pamela J. Jakes and David N. Bengston 2 

Forestry research evaluation is not a new 

idea or activity. We have traced the first 

forestry research evaluation to Bernard Fernow. 

In 1893, Fer now estimated potenti a1 increases 

in timber value from research on the physical 

characteristics of various timber species in an 

effort to justify an annual investment of 

$40,000 (USDA 1893). 

Although research evaluation is not new, 

interest in developing rigorous methods to 

evaluate the impacts of forestry research is 

new. Early forestry research evaluations used 

relatively informal, nonquantitative techniques 

to evaluate the general effectiveness of 

forestry research programs. Recent evaluations 

of forestry research have concentrated on 

identifying the specific impacts of new 

knowledge--knowledge embodied in new production 

techniques, more effective and useful products, 

or more refined management practices. Because 

of this focus, these evaluations have 

concentrated on applied, not on basic research, 

Recently public forestry agencies in the U.S. 

and Canada have initiated programs to develop 

methods and frameworks for eval uati ng forestry 

research, with a major objective of identifying 

and quantifying its impacts on the economy, the 

environment, and society. Why is this activity 

receiving increasing attention? How should or 

can we go about evaluating the impact of 

forestry research? Some answers to these 

questions are offered below. 

WHY EVALUATE FORESTRY RESEARCH 

Sever a1 major trends contribute to the growing 

i nterest in forestry research eval uation. 

'presented at the Symposium on Cur rent 

Topics in Forestry Research, November 4-6, 

1986, Gainesville, FL. 

'project Leader and Forest Economist, North 

Central Forest Experiment Station, U.S. 

Department of Agriculture, Forest Service, St. 

Paul, MN 55108. 

Abstract, --Recent trends in feder a7 research 

allocations and increasing scrutiny of research 

by the public have resulted in a growing 

interest in forestry research evaluation mong 

forestry research decisionmakers. Current 

research in this field concentrates on adapting 

and developing methods for evaluating the 

impact of forestry research. 

Keywords: Research management, program 

eval uation, forest pol icy. 

First, the level of funding for forestry 

research has been decl ining. The magnitude of 

the decline becomes apparent when we compare 

recent federal funding of Forestry research in 

the U.S. to funding of agricultural research 

(fig 1) One explanation offered for the gap 

between the funding level for forestry research 

and that for agricultural research is 

agriculture's long tradition of research 

evaluation. Agricultural research evaluations 

carried out over the past two or three decades 

have consistently shown high rates of return to 

agricultural research (Evenson et a1 . 1979). 

This has resulted in the widespread perception 

that investment in agr icul tur a1 research 

benefits society. Although we may feel that 

forestry research produces sirnil ar high payoffs, 

we have lacked, until quite recently, empirical 

evidence supporting this hypothesis. 

A second trend relating to budgets is the 

'bil itar ization" of research. Significant 

shifts in research priorities in recent years 

have resulted in more of the research budget 

going to national defense (fig. 2). In 1985, 72 

cents out of every federal research do1 lar went to 

defense programs (Norman 1985). This shift has 

resulted in increased competition mong nonmil itary research programs for the remaining 

federal research funds. 

Index 

220 

200 

180 

All Agricult 

Research 

Year 

Figure 1.--Growth in U.S. agricultural and 

forestry research budgets, 1975-1984 (Greger sen 

and Olmstead 1986). 
The third trend is increasing public 

participation in science and technology 

decisionmaking. In forestry this trend has been 

most evident in discussions on the use of 

pesticides and herbicides in forestry 

management. In agriculture, we have a striking 

example of how the pub1 ic can have a major 

impact on research programs in the recent legal 

battle in wbich the University of California was 

sued for the allegedly harmful social impact of 

its agricultural mechanization research (Martin 

and Ofmsead 1985). There may be an important 

lesson for the forestry research community in 

this action, as agricultural research 

decision makers have been widely criticized for 

not giving enough attention to the social 

consequences of their research. 

Why eval uate research? Because research 

evaluation can he1 p pol icy and decision makers 

meet the demands or opportunities resulting from 

these trends. John Fedkiw, Associate Director, 

Office of Budget and Program Analysis, USDA, has 

been quoted as saying "Evaluation results can be 

a powerful tool for research managers because 

such results provide a basis for disinterested 

judgment in a1 1 ocat i ng revenues to enhance 

national welfare or State welfare" (Fedkiw 

1985). And Robert Buckman, former Forest 

Service Deputy Chief for Research, has stated 

that, "Evaluation activities.. .give a legitimacy 

and a credibility to research" (Buckman 1985). 

HOW DO WE EVALUATE FORESTRY RESEARCH 

Research evaluations can be divided into two 

categories: impact evaluations and process 

evaluations (fig. 3). Impact eval uations focus 

on the impact of research innovations that have 

been adopted and put into practice. They 

analyze research inputs and outputs while 

treating the research process itself as a black 

box. Process evaluations peek inside the black 

box to analyze the process by which research 

inputs are transformed into outputs. Process 

:ent 

1976 1986 (est.) 

Perc 

100 , 

Figure 2.--Percent of U.S. federal budget by 

budget function, 1976 and 1986 (estimated) 

(National Science Foundation 1985). 

SO 

80 

70 

eval uations focus on the effectiveness or 

efficiency of deci sonmaki ng, resource 

a1 location, pl anning, and other research 

activities. 

.. 

.. 

.. 

The current research in forestry research 

eval uation focuses on impact evaluations. The 

research eval uat ions conducted in agriculture 

have provided a valuable starting point for 

research on forestry research evaluation. 

Research to date has illustrated that methods 

devel oped for agr icul tur a1 research eval uation 

may be used to eval uate some forestry research 

efforts. 

For exampl e, usi ng an economic sur pl us 

approach common in agriculture, Bengston (1984) 

evaluated returns to research resulting in the 

development of structural particleboard. He 

cal cul ated average internal rates of return 

ranging from 19 to 22 percent. Somewhat 

surprisingly, a sensitivity analysis indicated 

that the rates of return were very insensitive 

to estimates of research costs. Marginal rates 

of return ranged from 27 to 35 percent, 

suggesting that further investment in this type 

of research would produce attractive rates of 

return. 

60 

Westgate (1985) appl ied the method devel oped 

by Bengston to eval uate the impact of 

containerized forest tree seedling research. He 

cal cul ated inter na1 rates of return ranging from 

37 to 111 percent, depending on (1) the quantity 

of containerized seedlings produced in the 

future, (2) estimates of research costs, and (3) 

the pr ice discount of containerized seed1 ings. 

The internal rate of return was very sensitive 

to assumptions made for the latter two factors. 

50 

40 

30 

20 

10 

0 

A1 though agr icul tur a1 research eval uation 

methods are applicable in some forestry cases, 

we've identified five characteristics of 

forestry research that make it necessary to 

devel op eval uati on methods. 

.. 

.. 

.. 

.. 

3. 

c 

M Research Evaluation Methods 

Evaluations Evaluations 

Figure 3.--Impact and process evaluations in the 

context of the research process. 
Fir st, agr icul tur a1 research eval uations have 

focused almost excl usi vely on commodity 

research. Early forestry research eval uations 

have a1 so concentr ated on comodi ty research by 

evaluating research efforts in forest products 

and ut i 1 i zat i on and timber management. Thi s 

early emphasis in forestry is understandable--i t 

is relatively easy to identify the research 

inputs and outputs for these areas of forestry 

research, there is a market for the outputs 

that he1 ps establ i sh research benefits , data 

r equi red for eval uat ions are avai 1 able, and 

agr icul tur a1 methods can be adapted for the 

eval uation. However, commodity research is only 

a small portion of the total forestry research 

effort. Other areas of research, particularly 

those for which research benefits are not easily 

measured or valued, can not be evaluated using 

existing methods. We need to develop methods 

for evaluating commodity as we1 1 as 

non-commodity research. 

Second, methods currently available for 

research eval uation are useful primarily for 

case studies of specific projects or 

innovations. However, narrowly focused case 

study eval uations have been criticized for only 

consider ing highly successful research efforts, 

thus casting doubt on the representativeness of 

the evaluation results for a given field or 

industry. We need methods that will enable us 

to conduct more aggregate level evaluations of 

forestry research. Aggregate level research 

eval uations avoid the "success story" cr i t ici sm 

by ignoring individual innovations and by 

instead examining the re1 ationship between 

research in a broad area and the growth or 

productivity in an entire industry or sector of 

the economy, Pol icy implications are a1 so more 

credible from this type of evaluation. 

In one of the few aggregate research 

eval uations conducted, Greger sen et a1 . (1983) 

evaluated returns to investments in all forest 

products utilization research. Even with a 

conser vat i ve estimate of benef i t s and an 

extremely liberal estimate of costs, the 

calculated rate of return on the public 

investment in forest products uti 1 ization 

research was about 20 percent, At the 

University of Georgia, Fred Cubbage and Don 

Hodges are developing methods that will allow 

them to perform an aggregate-level analysis of 

the impact of public investments in forest 

management research. 

Third, most of the evaluation methods used 

to date have generated a single measure of 

worth re1 ated to economic efficiency. In 

forestry, we have found average rates of return 

ranging from 9 percent for forest fertil ization 

research in the Pacific Northwest (Bare 1985) 

to more that 400 percent for research leading 

to the development of the softwood plywood 

industry (Seldon 1985). For decision makers, 

economic impacts are seldom the primary 

criteria in determining policy or research 

program direction; therefore we need to develop 

multiple measures of the worth of a project. 

We need to develop methods for evaluating the 

impact of forestry research on society and the 

environment , as we1 l as the economy. 

In an effort to provide broader economic 

measures of research impacts, David Lewis and 

his students at Oklahoma State University are 

eval uati ng the useful ness of macro-economic 

statistics, such as mployment and income data, 

in research eval uation. These statistics can 

tell us more about impacts on society than the 

traditional measures of economic efficiency. 

Fourth, agricultural and forestry research 

eval uations have been a1 most excl usively ex 

post eval uations, analyzi ng the benefits and 

costs of past research. It is difficult to 

make decisions on current or future research 

programs using studies of past efforts. If 

evaluations are to be useful in research 

pl anning, management, and pol icymaki ng , ex ante 

evaluation methods are needed. Ex ante -- eval uations analyze the antic i pated impacts of 

research in progress or proposed for future 

funding. The development of methods for 

conducting ex arte eval uations of forestry 

research isTritical to the growth of forestry 

research evaluation as a vita1 segment of the 

broader di sci pl i ne of eval uation research. 

Fi nal ly, eval uation methods cannot be 

developed in isolation from the intended users 

of evaluations. We must understand how 

eval uati ons are used and by whom in order to 

produce useful , re1 evant eval uation methods. 

Most of the agricultural and forestry research 

eval uations have been oriented primarily 

towards education--that is, increasing 

knowledge in eval uation research. The 

challenge is to adapt and expand our effort to 

ensure that it meets the needs of individuals 

involved in forestry research resource 

allocation and policy formation. 

How do we evaluate forestry research? 

Although there are methods available to 

evaluate some of the impacts of applied 

forestry research, the answer to this question 

must be provided by the client (decision maker, 

pol icy maker, legi sl ator, citizen) conducting 

or requesting the evaluation. The issues 

important to that individual or group determine 

the impacts evaluated. Clients should be aware 

that methods are avail able for eval uating the 

economic impact of individual techno1 ogies. 

Additional methods for evaluating economic 

impacts are being developed as we1 1 as methods 

for eval uating social and environmental 

impacts. We will probably never be able to 

evaluate all impacts on equal terms, but we 

must recognize that a variety of impacts are 

possible and that all must be considered in a 

thorough eval uation. 
LITERATURE CITED 

Bare, Bruce. A case history of the regional 

forest nutrition research project: 

investment, results, and appl ication. Col lege 

of Forest Resources, Un i ver s i ty of 

Washington, Final Report for USDA Forest 

Service Project Number PNW 82-248; 1985. 

52~~- 

Bengston, David N. Economic impacts of 

structural particleboard research: an 

assessment. Forest Science, 30(3) : 685-697; 

1984. 

Buckman, Robert. Summary: reflections on 

forestry research evaluations. In: Risbrudt, 

Christopher D.; Jak.es, Pamela J., eds. 

Proceedings, forestry research evaluation: 

current progress, future directions; 1984 

August 20-21; Roseville, MN. Gen. Tech. Rep. 

NC-104. St. Paul , MN: U.S. Department of 

Agriculture, Forest Service, North Central 

Forest Experiment Station; 1985:128-130. 

Evenson, Robert E,; Waggoner, Paul E.; Ruttan 

Vernon W. Economic benefit from research: an 

example from agriculture, Science 

205:lOl-107; 1979. 

Fedkiw, John. Research eval uation and 

pol icymaki ng. In: Ri sbr udt , Chr i stopher D. ; 

Jakes, Pamela J., eds. Proceedings, forestry 

research evaluation: current progress, future 

directions; 1984 August 20-21; Roseville, MN. 

Gen. Tech. Rep. NC-104. St. Paul, MN: U.S. 

Department of Agriculture, Forest Service, 

North Central Forest Experiment Station; 

1985 : 5-9. 

Greger sen, Hans ; Olmstead, James. Assessment of 

methods used to plan and budget forestry 

research programs. Col lege of Forestry, 

Uni ver si ty of Minnesota, Fi na1 Report for 

USDA Forest Service Project Number 

NC-23-82-22; 1986. 158~~. 

Gregersen, Hans; Waygreen, John; Hol land, Irv. 

Impacts of forest utilization research : an 

economic assessment. College of Forestry, 

University of Minnesota, Final Report for 

USDA Forest Service Project Number 

FP-1981-0395; 1983. 97~. 

Martin, P.L. ; Olmstead, A. L. The agricultural 

mechanization controversy. Science 

227: 601-606; 1985. 

National Science Foundation. 15% increase in 

Federal R&D funds proposed in 1986 budget, 

mostly for defense. Science Resources Studies 

High1 ights, July 31. NSF 85-322, kashington, 

D.C. : National Science Foundation; 1985. 4pp. 

Norman, Collin. The science budget: a dose of 

austerity. Science 227:726-728; 1985. 

Seldon, Barry. Supply functions and social 

returns to research. In: Risbrudt, 

Christopher D.; Jakes, Pamela J., eds. 

Proceedings, forestry research eval uation: 

current progress , future di r ect i ons ; 1984 

August 20-21; Rosevil fe, MN. Gen. Tech. Rep. 

NC-104. St. Paul, MN: U.S. Department of 

Agriculture, Forest Service, North Centr a1 

Forest Experiment Station; 1985: 111-115. 

U.S. Department of Agriculture. Report of the 

Chief of the Division of Forestry for 1892. 

Washington, D.C: Division of Forestry, U.S. 

Department of Agriculture. 1893. 

Westgate, Robert. Returns to investment in 

forestry research: the case of containerized 

forest tree seed1 i ngs. In: Ri sbr udt , Christopher D. ; Jakes, Pamela J., eds. 

Proceedings, forestry research eval uation: 

current progress, future directions; 1984 

August 20-21; Roseville, MN. Gen. Tech. Rep. 

NC-104, St. Paul, MN: U.S. De~~rtment of 

Agriculture, Forest Service, North Central 

Forest Experiment Station; 1985: 117-120. 
C. Denise Ingram, Jan 6. Laarman, and Michel 6. 

Contezac 2 

The authors are, respecti vely, Forester, USDA 

Forest Service, Southeastern Center for Forest 

Economics Research, Southeastern Forest Experiment Station, P. 0. Box 12254, Research Triangle 

Park, NC 27709; Associate Professor, Department 

of Forestry, Box 8002, North Carolina State University, Raleigh, NC 27695-8002; and Writer, USDA 

Forest Service, Forest Products Laboratory, P. 0. 

Box 5130, Madison, WI 53705. The research was 

funded by a cooperative research agreement cosponsored by the US Agency for International 

Development and the USDA Forest Service. Parts 

of this study were included in Ingram's M. S. 

thesis, North Carolina State University. 

The Forest Products Laboratory (FPL) of the 

USDA Forest Service has gained international 

recognition as a leader in wood utilization 

research. Since its establishment in 1910 on the 

campus of the University of Wisconsin, FPL has 

grown to the point where it now employs about 300 

scientists, professionals, technicians, administrative, and other staff. In addition to 

addressing research needs of the forest products 

sector in the United States, a part of FPL's 

mission is to "provide worldwide expertise on the 

technical aspects of wood." Thus, among FPL's 

technology transfer activities is the distribution of technical articles, features, and written materials to more than 2,000 foreign 

addresses. Additionally, FPL regularly schedules 

tours, programs, and technical conferences and 

meetings for special groups, including a large 

number of foreign visitors and scientists. 

This paper assesses the sources, growth and 

subject matter of foreign (non-US) requests for 

information and services provided by FPL over 

States for information and services provided by 

FPL, uses this classification to catalog FPL's 

lsymposium on "Current Topics in Forest 

Research: Contributions by Women Scientists. " 

Nov. 4-6, 1986, Gainesville, FL. 

 o or ester, USDA Forest Service, Southeastern 

Center for Forest Economics Research, P.O. Box 

12254, Research Triangle Park, NC 27709; Associate Professor, Department of Forestry, Box 

8002, North Carolina State University, Raleigh, 

NC 27695; and Writer, USDA Forest Service, 

Forest Products Laboratory, P.O. Box 5130, 

Madison, WI 53705, 

Abstract 

In the period 1955-84 the USDA Forest Service's 

Forest Products Laboratory (FPL 1 recei ved approximately 3,000 requests for information and services from forei gn (non-US) sources. Requests 

from outside of the United States have grown from 

fewer than 50 per year in 1955-70 to more than 10 

times that number in 1984. Approximately twothirds of the requests have originated in industrialized countries. More than three-fourths are 

from private firms and individuals, together with 

research and educational organizations. The most 

frequent form of technology transfer is through 

direct visits to FPL in Madison, WI. Foreign 

requests for FPL's services have ranged broadly 

across a number of technical fields: economics 

and utilization, manufactured boards, protection 

and preservation, pulp and paper production, wood 

properties, and wood energy. Requests by technical fields have been largely similar when comparing industrialized with non-industrialized 

Keywords: technology transfer, forest products, 

international. 

records of requests for such forei gn-oriented 

information and services, and describes the major 

and minor lines of FPL 's forei gn-oriented techni cal assistance. 

ANALYSIS 

Description of Data 

Data for this study were obtained from FPL's 

general correspondence files in Madison. All 

correspondence to FPL during the 30-year period 

1955-1984 was surveyed. Recording forms were 

used to document requests for services, information, materials, etc., from foreign sources 

according to the following format: (1) country 

and year of request, (2) type of institution represented by the request, (3) type of information 

or service required; (4) technical subject of 

and requests are defined and discussed indi vidually in the following sections. 

Region and Time Period 

FPL's requests from foreign sources were documented by country and year. These data were then 

aggregated according to nine geopolitical regions 

and three 10-year time periods. The results are 

shown in Table 1. 

Of the nearly 3,000 requests reported here, 

those from mainly industrial ized regions outnumbered those from mainly non-industrial ized regions by a ratio of 2:l. Only in the first subperiod (1955-64) did non-i ndustri a7 ized regions 

dominate. For the past three decades as a whole, 

foreign requests for FPL's services were led by 

Europe, Asia, and Canada, respectively. 
Table 1. FPL's foreign requests, by world region. Types of Institutions 

World Reg~on 1955-64 1965-74 1975-84* Total The requests for technical information and services were classified by the type of institutions 

represented: private, governmental, educational 

international agency, or research. The classif ication was based entirely on information contained 

in the letterheads and correspondence. Thus 

assignment to one category or another is inherently 

affected by a high degree of researcher 

subjectivity. A part of this problem arises 

because the categories are overlapping and not 

always separable. For example, universities, 

government laboratories, and private firms often 

engage in research and are considered research 

institutions themselves. 

------------- No. of repuests ------- 

Industriaiized 

Austrailia 8 New Zealand 

Canada 

Europe and USSR 

Japan 

Subtotal 

Won-industr:al:zed 

Africa 

Asia (ex. Japan) Subject to these limitations, Table 2 shows that 

requests have been dominated by private organizat ions and individuals, research organizations and 

educational institutions (mainly universities). 

For the 30-year study period, these three types of 

institutions accounted for more than three-fourths 

of FPL's requests from outside of the United 

States. 

Latin Awrica & Caribbean 

Middle East 

Oceania (ex. Aust. L N.Z. ) 

Subtotal 

Ail reg:ons (Totals) 

*Data are not complete for yeprs 1971-79. 

Tahie 2. FPL1s fore'gn requests, by type of inst:tution mak:'?g the request. 

In some regions the bulk of foreign requests 

originated from just a single country. For 

example, India and the Republic of South Africa 

accounted for more than half of FPL's requests 

from Asia (excluding Japan) and Africa, respecti vely. 

Figure 1 shows the annual numbers of foreign 

requests during the study period. Because of 

missing data, numbers of requests are not shown 

for the years 1977-1979. The time trends of 

requests from industrialized and noni ndustri al ized regions move in roughly parel lel 

fashion. Requests increased dramatically after 

1971, and again after 1982. 

i ~ternational agency 24 5 63 92 

(Not def lnedi (9) (47 ) !79) (1351 

- Totdl .-- 247 37 3 : 99u 2>10 

*Data a-v n'i: comjiittr f?r yea:~ 1977-79. 

Types of Information and Services 

The requests were classified according to the 

types of information and services asked of FPL. 

The categories of requests were: visits to FPL's 

facilities in Madison, professional advice on 

technical procedures and research analysis, 

pub1 ications and research materials (e. g., wood 

samples, chemical compounds ), services to be performed (e.g., testing and operational ), FPL scientists to participate in international conferences 

and, through cooperative agreements between FPL 

and foreign institutions, to provide study, 

training, and research experiences for forei gn students and scientists in the United States. 

Regions 

& too- ! l 

:Nan-~noustr~all 

: Rag ons 

Table 3 indicates that, since the late 1960s, 

the most numerous requests concerned visits to 

FPL's facilities in Madison. Requests to visit 

FPL, requests for professional advice, and 

requests for pu bl i cat ions and materi al s accounted 

for four-fifths of all foreign inquiries during 

the last two subperiods. 

YEAR 

ftgur. 1 FPL'S Foreign Raquests. by Y*.f 

Bec.ure of mtsrlng dale numbers tor 1977-79 ere not 

plOft@d 
Table 3. FPL's foreign requests, by type of inforrnat.cn or serv3ce requested. 

SUBJECT Type- of 1nformatlon 

-- or service requested 1955-64 1965-74 1975-d4* Total 

'4-s-ts to FPL 14 2tlt 61b *3b 

Profess'ona 1 adv:ce db 147 490 723 

Puhl:cat-orrs & mat pr7ais 19 92 477 588 

T~chn-rdi serv~ces 8 46 1 Rr 242 

-- Tctais -- 32, 3 / 19 '5 2,515 

_ -_-_____ 

*~cta arp not conyipte fn- y-3-5 lQ77-7.'. 

But during the first subperiod 1955-64, more 

than half of the requests originated through 

coperative agreements. Most of these agreements 

were administered through the International 

Cooperation Administration (ICA), predecessor of 

the Agency for International Development (AID ). 

The ICA provided funds for training and study by 

foreign indi viduals at the Madison faci 1 ity, 

often in conjunction with the University of 

Wisconsin. By 1965 the ICA support had essentially disappeared, and a reduced level of 

foreign contact with FPL was maintained through 

the funds of Public Law 480 (often called the 

"Food for Peace" program). For the 30-year 

period, approximately two-thi rds of FPL's foreign 

requests under these cooperative agreements 

originated in non-i ndustrial ized countries. 

Technical Subjects 

The requests were distributed over a wide 

variety of technical special it ies in forest products technology. The survey recognized the 

following seven categories: wood properties, wood 

protection and preservation, manufactured boards, 

pulp and paper production, economics and utilization, wood energy, and other. Often a single 

request or contact, such as a visit to FPL, was 

motivated by interests in more than one 

subject. In these cases, all of the different 

subject areas were recorded separately. 

Additionally, some inquiries were directed 

towards broad research programs at FPL, and these 

requests were classified as "general ". 

Figure 2 shows the distribution of requests by 

technical subjects for the industrialized and 

n o n - i n d u s t r i a l i z e d regions separately. These 

distributions were highly similar. For both 

industrialized and non-industrialized regions, 

requests were spread quite evenly across protection and preservation, economics and utilization, 

pulp and paper production, and wood properties. 

Manufactured boards and wood energy were relatively less important, despite the popularity of 

wood energy issues during the past few years. 

PP 

WP 

PPP 

E U 

Y B 

WE 

OTHER 

GENERAL 

PERCENTAGE 0 5 10 15 20 250 5 10 15 20 25 

Industi~al~zod Non-tndustf~al~zmd 

Reg tons Regions 

F~guro 2. FPL's Forotgn Roquestr, by Tochnicol Subject 

Percmntagos are for protoction end praoarvaltonlPPI, wood 

properties IWPI, econom$ca and ut~liz~tlonlEUI, pulp and papel 

productionIPPP~,mrnufacturod boordslMB1, Wood enorgy IWEI, 

OTHER and GENERAL 

DISCUSSION 

The data and observations presented here attest 

to the international stature of FPL, and the 

remarkable growth in its service to the world's 

forest products industries. This growth is 

inferred from FPL 's correspondence f i les alone, 

which is only one indicator of FPL's contacts and 

technical exchanges at the international level. 

Travel and communication in a "global village" 

make FPL accessible to increasing numbers of 

scientists everywhere. We do not claim that 

the data presented are highly accurate. A survey 

of government files spanning three decades is 

bound to contain inconsistencies and incornpatibi lities from year to year. The period is 

sufficiently long that many countries changed 

political boundaries and names, and many new 

developments occurred in forest products technologies. Hence, readers should regard these 

survey data as broadly indicative, not quantitat i vely precise. 

There are many policy questions which come to 

mind when reviewing technology transfer acti vi - ties within an organization. Can and should FPL 

include technology transfer object i ves for international clientele? If so, what is the optimal 

mix of domestic U.S. international service for 

public agencies? The pattern of requests by 

technical subjects is broadly simi lar when comparing the non-industrialized and industrialized 

regions. Is this an accurate reflection of 

reality? What are the implications for the issue 

of "approriate technology"? The answers to these 

and other policy questions can only be addressed 

by the analysts and decision-makers of the USDA 

Forest Service and FPL. Today's complex market 

for international goods and services and the 

growing coinpetition by non-industrial ized 

countries in these markets require close attention by policy makers to the issue of technolol gy transfer. 
State Forest Practice Regulation -- 

The hssachusetts and California Cases 1 

Terry K, Waines and Williarn C, Siegel 2 

A major component of public forest policy in th 

United States concerns the appropriate role of 

government in the management of private forest 

lands. This question has been widely debated in 

America for more than a half century. Presently 

governments a t a l l levels influence private 

forestry practices through such policy tools as 

taxation, direct and indirect subsidies, and 

formal regulation. Historically, regulatory 

control has been the most controversial of these 

influences. 

HISTORICAL EACKGROUND 

Public regulation of private forest lands was 

first introduced in North America in the early 

17th century when the Plymouth Colony passed a law 

that prohibited the cutting of trees without 

official permission (siegel and Cubbage 1985, 

Huffman 1978). A nunber of other regulatory laws 

controlling timber cutting were later passed in 

many of the colonies (~awashima and Tone 1983). 

After the Declaration of Independence, however, 

public regulation of private forestry practices 

received scant attention which resulted in widespread timber exploitation and waste that continued unabated for more than 100 years. Public 

concern finally led to federal legislation in the 

late 19th and early 20th centuries that authorized 

set-aside of public lands and federal purchase of 

private lands for forest preserves--later designated as national forests. Regulation was not 

seriously considered at that time. 

Extensive debate over public regulation of 

private forestry in the United States did not 

begin until about 1917 and continued through the 

' paper presented at National Symposium of Current 

Topics in Forest Research: Emphasis on Contsibutions by Women Scientists, November 4-6, 1986, 

Gainesville, Florida. 

2~orester and Project Leader, respectively, Law 

and Economics, Southern Forest Experiment Station, 

U.S.D.A, Forest Service, New Orleans, Louisiana. 

Abstract.--The current status and legal background 

of forest practiee regulation in the United States 

is briefly discussed. The California and Nassachusetts statutes, the most comprehensive in their 

respective regions, are examined in more detail. 

For both States, historic perspectives are analyzed; important statutory and regulatory provisions discussed and compared; and proposed legislative changes and current administrative trends 

identified. State forest regulatory trends within 

the context of using public regulation as a policy 

tool to control forest landowner activities are 

briefly examined. 

Keywords: Forest policy, forestry practices, 

public regulation, forest protection, private 

landowners. 

mid-1920% (siegel and Cubbage 1985). In 1919, 

both the U.S. Forest Service and the Society of 

American Foresters began campaigning for federal 

regulatory legislation. Even though these 

attempts resulted in legislation actually being 

introduced in Congress, all failed. 

The debate began once again in the late 1930's 

(3iegel and Cubbage 1985). Fearing that an onerous 

federal regulatory law would be enacted if they 

failed to respond at the State level, 15 States (10 

in the East and 5 in the west) passed legislation 

between 1937 and 1949 for the control of forestry 

practices on private woodlands (~ubba~e and 

Ellefson 1980). The primary purpose of these laws 

was to counter the threat of timber shortages by 

requiring adequate regeneration after harvest-- 

usually in the form of a seed tree requirement. 

Enforcement was generally mild in the East and 

strict in the West. The call for further regulation largely disappeared during the 1950's and 

1960%, with only one additional state forest 

practice act being passed. 

THE LEGAL FRAMEWORK OF PUBLIC REGULATION 

A firm legal basis for public regulation of private forestry practices has existed for many years 

(cubbage and Siegel 1985). The courts have unanimously ruled that such regulation is constitutional 

if enacted to protect the public health, safety, 

morals, or general welfare. Use of the statees 

police power to restrict landowner activities in 

this regard is discussed in Carrnichael (1 975). 

Forest practice laws have usually been challenged 

in court on the basis of the 5th hendmenth taking 

clause which prohibits the public taking of private 

property without just compensation. This constitutional provision is generally applied to the individual States through the due process and equal 

protection clause of the 14th Amendment aster 

1983). In that respect, the courts have held that 

forest practice regulation is an appropriate exercise of police power if it does not discriminate 

among anal applies equally to all forest owners. 

State v. Dexter (32 Wash. 2d 551, 202 P. 2d 906, 

70 3. Ct* 147 [I 9473) is the lanbark decision 
involving State forest practice legislation. The 

only such case to reach the U.S. Supreme Court, it 

concerned a violation of the Washington state 

forest practice statute. The defendant maintained 

that the requirements specifying that trees below 

a certain diameter could not be cut, and that a 

cutting permit had to be obtained before logging, 

was the equivalent of taking private property 

rights without compensation and due process 

(siegel 1974). The trial court ruled for Dexter, 

but the Washington State Supreme Court reversed 

and held the law to be constitutional. Its decision was upheld by the U.S. Supreme Court. The 

Dexter decision has been frequently used in subsequent years to support the enactment of forest 

practice regulatory statutes. 

CURREBT FOREST PRACTICE LAWS 

After a relatively quiet period during the 

1950's and d9601s, attention was once again 

focused on State forest practice legislation 

during the 1970's and 1980's. 

Since 1970 a number of States have enacted comprehensive legislation to regulate forest operations on private, and in some instances, public, 

forest land. The older laws passed prior to the 

1970's emphasized timber production and reforestation (siege1 and Cubbage 1984). The modern 

laws, however, set standards for a variety of 

forest management activities that include timber 

harvesting, regeneration, road construction, and 

slash disposal. They also attempt to protect a 

wide range of other forest resources such as water 

quality, soil productivity, fish and wildlife, air 

quality, and in some cases, aesthetics. These 

statutes are a response, in part, to the environmental movement of the 1960's and 1970's. The 

Western States, in particular, have many forested 

areas on steep slopes with highly erodable soils 

and near streams. These sites are very sensitive 

to forest operations. Another force behind enactment of the newer laws has been the Federal Water 

Pollution Control Act Amendments of 1972. This 

legislation requires the individual States to 

develop water quality management plans for the 

control of nonpoint source water pollution, 

including that emanating from silvicultural 

activities. 

Enhancement of forest productivity is in the 

best interest of many western states. Because 

forest industry is very important to their economies, six Western States--Alaska, California, 

Idaho, Mevada, Oregon and Washington--currently 

have a forest practice law enacted or revised 

during the 1970's. In addition, New Mexico has 

an older forest conservation law that is rather 

narrow in scope. It sets standards for tree 

utilization, slash disposal and fire control measures. fvlassachusetts is the only State in the 

East with a comprehensive modern law. However, a 

number of other Eastern States have legislation 

affecting forest practices. Maine regulates forest operations through a zoning law that primarily 

restricts forest activities in the enviromentally 

sensitive area of the unincorporated townships of 

the State. Approximately 28 percent of the forest 

land in these townships is subject to the law. 

New Hampshire and Vermont have piece-meal systems of forest practice regulation. Each has 

several laws to regulate specific forest activities. 

Florida, Naryland, Missouri, Mew York and Virginia have regulatory legislation originally 

adopted in the 1940's or 1950's--although some 

have been amended in recent years. Maryland also 

has a separate seed tree law adopted in 1977. The 

statutes of Maryland, Virginia, and Florida are 

primarily concerned with ensuring proper reforestation of cutover sites. Those of New York and 

Missouri address a broader range of activities, 

but compliance with them is strictly voluntary in 

return for forest management assistance from the 

State. Missouri also grants a tax subsidy to 

those who follow its rules. 

Although forest practice regulation in the East 

has not been as comprehensive or severe at the 

State level as in the West, in recent years there 

has been a proliferation of local ordinances in 

several Eastern States. In some cases, these have 

been very restrictive or even prohibitive to 

timber operations. For example, among the 567 

municipalities in New Jersey, about 100 have 

established ordinances restricting timber operations (~o~an 1984). 

Modern forest practice legislation in the United 

States has significant implications for the 

Nation's forest resources. An examination of the 

history, development, and major provisions of 

these statutes indicates that they have indeed 

been a major component of forest policy during the 

last several decades. The California and Massachusetts laws, as the most comprehensive of their 

respective regions, provide excellent illustrations of the developing role of regulation in forest policy and how the approach has differed in 

the West as compared to the East. As Western 

States without regulatory legislation consider 

enactment of such statutes, they will certainly 

examine closely the regulatory experience in California. Similarly, the proliferation of local 

laws in the East may prompt many States in that 

region to consider State legislation similar to 

that of Rassachusetts. For these reasons, we have 

examined and compared the California and Massachusetts laws in terms of major provisions, costs, 

effectiveness, and implications for other States. 

Conclusions will follow. 

THE CALIFORNIA AND MASSACHUSETTS STATUTES 

The Forest Practice Act of 1945, adopted primarily to control destructive harvesting practices associated with meeting World War I1 wood 

needs and to defuse threatened federal legislation, was the first California law to regulate 

forest practices. This statute regulated harvesting practices to insure reforestation and 

protection of residual stands but was declared 

unconstitutional in 1971. The court found 
(Bayside Timber Co. v. Board of Supervisors of San 

Hateo County, 97 Cal. Rptr. 431) that the members 

of the Board of Forestry and the District Committees, who were responsible for preparation and 

adoption of rules, had a pecuniary interest in the 

regulation of forest practices. It also objected 

to the provision of the law that required approval 

of two-thirds of the owners of private timberland 

prior to adoption of forest practice rules. The 

1945 law was replaced in 1973 by the Z'bergNejedly Forest Practice Act which stipulates that 

the membership of the Board and District Committees shall include five members from the general 

public. These members, who constitute a majority, 

may have no direct financial interest in timberland. Furthermore, the provision requiring the 

approval of forest landowners was removed from the 

Act. The current law has been modified extensively since its original enactment, by both 

legislative amendment and the courts. 

In contrast to California, forest practice 

legislation in Massachusetts has been subject to 

little or no litigation. The current law regulating forest practices is the 1983 Forest Practices 

Cutting Act. An earlier Cutting Practices Act had 

been passed in 1943 in response to the forest 

devastation resulting from a 1938 hurricane. That 

law required, as a minimum, that seed trees be 

left after harvesting to insure regeneration. 

Landowners were also required to give notice of 

their intent to cut and the State was charged with 

preparing a cutting plan. Over the years it 

became too much of a burden for the State to prepare all the required plans and to administer the 

Act effectively. As a result, in 1977 the Governor's Committee on Policy called for radical revision of the law. This played a major role in 

adoption of the 1983 statute. Two other factors 

also influenced its enactment. 

First, compliance with provisions of the State's 

Wetlands Protection Act was impeding logging 

operations and creating c stly delays in harvesting of up to 45 days.' The new law is coordinated with the Wetlands Act, and an administrative 

agreement with the Department of Environmental 

Quality and Engineering has eliminated many of the 

delays. The third factor in the adoption of the 

current law was the rapid proliferation of local 

ordinances regulating forest operations, some of 

which have been highly restrictive. 

General Provisions 

The stated intent of both the Massachusetts and 

California laws is basically the same--to maximize 

the timber resource while at the same time protecting all other forest resources. The Massachusetts law regulates activities on all public and 

private forest land. The California statute, by 

contrast, is applicable to all nonfederal public 

and private woodland, 

?~ele~hone interview with Thomas Quink , Chief 

Forester, Massachusetts Division of Forests and 

Parks, Boston, July 1986. 

Certain activities are exempt from regulation 

in both States. In Massachusetts these activities 

include cutting for right-of-ways, small commercial harvests of up to 25,000 board feet or 50 

cords, and clearing for conversions to other land 

uses. California exempts operations on parcels of 

land 3 acres or less in size, removal of dead or 

dying trees, and cutting of fuelwood. Exemptions 

in California, however, only apply to certain 

administrative filing requirements. The operations must still comply with all other rules and 

regulations of the Act. 

The California Forest Practices Act of 1973 did 

not initially preempt county rule enactment and 

local ordinances stricter than their State counterparts were adopted. However, a 1981 amendment 

removed this county authority. The amendment gave 

the Board of Forestry the authority to issue, at 

its option, county specific rules upon recommendation of the county. To date this has been done 

for five counties. 

The Massachusetts Act does not currently limit 

the authority of local governments to promulgate 

rules. Although the state law to date has satisfied the regulatory needs of most local governments, an amendment to control enactment of local 

ordinances is being considered. 

Administrative Rule Establishment 

The two laws also differ in their method of 

establishing administrative regulations. The 

Massachusetts forest practice law directs the 

Division of Forest and Parks to adopt one set of 

rules that apply to operations in the entire 

State. To insure protection of nontimber 

resources, the rules must also be approved by 

the Department of Environmental Management. The 

California law, however, directs the Board of 

Forestry to divide the State into at least three 

districts. Each district has a separate set of 

rules promulgated by an appointed committee. To 

achieve a balance between timber and nontimber 

interests in the rule-making process, the Board 

must maximize cooperation and input from other 

State resource agencies in the rule making process. Both laws provide for public input in the 

rule-making process by requiring that public 

hearings be held prior to adoption or revision. 

The rule-making bodies in California are each 

composed of nine members, five of whom may have no 

financial interest in timberlands. This membership composition provides points of view that may 

not be present on the Massachusetts forestry 

rule-making committee. The latter is composed by 

law of eight members, four of whom by definition 

have a financial interest in forestry. The eightmember committee must include a forest landowner, 

a representive from the primary wood-using industries, a licensed timber harvester, a consulting 

forester, three representatives of other resource 

interests, and one person representing the general 

public. This appears to give a fairly balanced 

membership, but close examination of the current 

board reveals a preponderance of interests in 
timber. Currently, the public member is a Massachusetts tree farmer and at least one member representing other resource interests is involved in 

forestry and the Tree Farm Program. Thus, at present, 6 of the 8 committee members have a financial 

interest in forestry. The requirement that rules 

prepared by the Massachusetts Cornittee be approved 

by the Department of Enviromental Quality before 

final promulgation appears to provide for further 

review of the rules and their impact on forest 

resources. However, this may not be the case. The 

Commissioner of Environmental Management is also 

the State Forester and his approval is generally a 

mere formality. 

Practices Addressed By Regulation 

Rules in both States require timber operators to 

be licensed. The rules also address harvesting 

systems to be used, regeneration methods, logging 

practices, road construction, and slash disposal. 

Clearcut size and the use of shelterwood and seed 

tree cuts are included in the regulations. Massachusetts limits clearcut size to 10 acres. Larger 

areas may be allowed if approved by the State in 

the cutting plan. In California, the maximum 

allowable clearcut is dependent on the site's erosion potential. The size may range from 80 acres 

for a site with a low erosion potential to 20 acres 

in areas with an extremely high potential. 

Both States require minimum stocking standards 

to be met after harvest. The Massachusetts law 

mandates establishment of 1,000 seedlings per acre 

within 2 years of harvest. In California, the 

number of seedlings required varies depending on 

the productivity of the site. Fiegeneration standards must be met within 5 years of harvest. 

Both the Massachusetts and California rules 

require that care be taken when conducting forest 

operations such as tree felling, use of logging 

equipment, yarding, and construction of roads and 

skid trails. However, the regulations in California are considerably more detailed and prescriptive than those in Massachusetts. For example, 

they include specific rules concerning the proper 

installation of drainage structures, the allowable 

distance between water bars, treatment of fill and 

surfacing materials, and maintenance requirements. 

The Massachusetts regulations require only that 

adequate ditches, culverts and water bars be provided. 

Each State's law gives special attention to 

operations in wet areas, on steep slopes, and in 

the vicinity of lakes and streams. In addition, 

Massachusetts requires that specialized harvesting 

and road construction practices be used in aes thetically sensitive areas. 

Administrative Procedures 

Detailed administrative procedures are required 

in both States for conducting forest operations. 

However, filing requirements of the California act 

are more complex and numerous than those in Massachusetts. 

Massachusetts requires a notice of intentlforest 

cutting plan, notice to abutters if cutting will 

occur within 200 feet of another's property, and a 

notice of completion. An additional form is 

required for operating in a wetland or on steep 

slopes. The notice of intentiforest cutting plan 

is a check off/fill-in-the-blank type of form. It 

addresses silvicultural methods, method of designating trees to be cut, estimated volume of species 

on the site, logging and erosion control measures, 

special procedures in buffer strips, and measures 

to control mud on highways. Both a detailed map of 

the operation site and a locus map outlining the 

cutting area on a U.S. Geological Survey topographic map are required. Cutting plans are 

subject to review and approval by the Division of 

Forest and Parks. Although plan requirements are 

complex, the law does not require that they be 

completed by a forester as in California. 

Currently, all operations in Massachusetts are 

inspected prior to, during, and upon completion 

of logging. Proposed harvesting in wetlands is 

always inspected prior to harvesting plan 

approval. Decisions of the Division may be 

appealed by the operator or landowner to the 

Director of Forests and Parks and ultimately to 

the Superior Court. 

The sites associated with approximately 80 percent of all California harvesting plans submitted 

are inspected prior to plan approval. Selection 

of sites is an administrative decision. Furthermore, a11 operations are inspected at commencement, during'operations, and upon completion. 

The California Act requires preparation of a 

timber harvesting plan by a licensed forester; the 

plan is then submitted to the Department of Forestry for approval, Several legislative modifications have been made over the years to render harvesting plans the functional equivalent of the 

State environmental impact reports. These changes 

were made in response to Natural Resources Defense 

Council v. Arcata National Corp. (1 Civ. No. 

37555, Cal. Ct. App. 10th Dist. [JU~~ 8, 19761) 

where the court ruled that timber harvesting plan 

approval was subject to the environmental review 

requirements of the State's Environmental Quality 

Act. As a result, the forester must conduct a feasibility analysis to evaluate possible activities 

that might be conducted to lessen adverse environmental effects. In addition, the soil erosion 

hazard rating of each site must be determined. 

The timber harvesting plan in California is also 

a check off/fill-in-the-blank form that addresses 

silvicultural methods, harvesting and erosion control practices, road and landing construction, 

special operations near water, and hazard reduction. As in Hassachusetts, the owner or operator 

must also submit a detailed map of the operation 

site. Harvesting plans are subject to review by 

the California Department of Fish and Game, the 

State Water Quality Control Board, and district 

interdisciplinary teams. 

Landowners in California are required to supply 

the Department of Forestry with the names and 
addresses of adjoining property owners within 300 

feet of the cutting boundaries- The Department 

then notifies abutters of Lbe proposed operationsThe landomer must also notify the Department when 

operations are completed. Periodic stocking 

status reports are then required until stocking 

rneets minimurn standards. 

If California owners sell their property during 

harvesting, they must infom the purchaser of the 

forest practice regulations regarding stocking 

standards after harvesting. Otherwise, the prior 

owner may be held responsible for reforestation 

costs . 

Timberland conversions in California require a 

permit and may be denied if the state determines 

that the site would be better left in timber production. In contrast, conversions in Massachusetts require no approval. 

Enforcement 

Tools for enforcing forest practice rules are 

provided in the laws of both States. Legal 

actions are avoided if possible. Agency personnel 

prefer to achieve compliance by providing the 

operator and/or owner with educational or technical assistance. 

When necessary, each State may issue stopwork 

orders. In Massachusetts the order remains in 

effect until deficencies are corrected or until a 

hearing is held. In 1984, 1,059 harvesting plans 

were submitted with only 25 stopwork orders being 

issued -- either for failure to submit a cutting 

plan or for failure to follow practices approved 

in the plan. No violations of the Act have 

resulted in judicial action to date. In addition 

to stopwork orders, the Superior Court may levy a 

fine of up to $100 per acre for failure to make 

the necessary administrative filings and for violating rules. Failure to obtain an operator's 

license is subject to a fine of up to $1,000 per 

violation. Thus far, no fines have been imposed 

nor licenses revoked for violation of the Forest 

Practice Act (8enly and Ellefson 1986). 

In California, a forest practice inspector may 

issue a temporary stopwork order that is effective 

for up to 7 days* If the infractions are not corrected, court action may be sought. The courts 

can order that irmediate corrective measures be 

taken by the responsible party. If repairs are 

not made, the courts may authorize the Department 

of Forestry to take corrective action itself at 

the expense of the responsible party. Expenses 

incurred may result in a lien on the property 

involved. 

Violations of the California Act are punishable 

by a $1 ,OW fine and/or 6 months in jail. Each 

day of a violation is considered a separate 

offense. In 1984, 964 of the 1,260 timber harvesting plans submitted were found in violation of 

the law. Of these, 40 resulted in enforcement 

actions but only in one instance was of an operator's license suspended. 

The California forest practice law requires 

nmerous and more detailed administrative filings 

than does the gassachuselts statute. The 

California law is also more explicit regarding 

actions that should be taken to achieve a particufar perfomanee standard. In Eassachusetts, 

omers or operators have nore discretion in 

selecting specific practices to achieve compliance 

with the standards, 

Economic and Cost Considerations 

The laws of both States, although differing in a 

number of respects, have been moderately to highly 

effective in protecting and enhancing both timber 

productivity and nontimber resources (13enly and 

Ellefsoa 1986), 

Estimates of the cost of compliance with the 

California Act range from $25 to $80 per thousand 

board feet (~enly and Ellefson 1986). A major 

cost is for preparation of the timber hamesting 4 plan; this averages $1,000 . Complex plans, however, mag cost as much as several thousand dollars. The expenses incurred by small landowners 

may be proportionally much higher than those of a 

large landowner for similar plans. The costs of 

complying with other requirements are more difficult to quantify. However, the Act has resulted 

in an annual state-wide increase in reforestation 

expenditures of $2 do $3 million (~aux 1983). 

There has been some speculation that the California Law would have an overall negative impact 

on forest inveskment in the State. For example, 

the increased cost of eoatpliance may have been a 

factor in the divestment of California holdings by 

both Weyerhauser and International Paper companies 

(~enl~ and Ellefson 1986). Although a decrease in 

timber production was anticipated, two recent 

studies found no evidence that the level of timber 

produced in California has changed since passage 

of the Forest Practice Act r re en and others 1981 , Henly and Ellef son 1 986). 

Id is too early do determine in a meaningful way 

the economic implications of the Hassachusetts 

Act. At least several more years experience will 

be needed. 

Conclusions 

Regulation of forest practices and enforcement 

of the rules in California are generally much 

stricter than in &ssaehusetts- Certainly one 

factor responsible for the difference is the 

greater potential for danrage to the enviroment in 

California, with its steep slopes and fragile 

soils, as compared to Hassachusetts. Since both 

States are well hewn for their active enviromental groups, that alone would not necessarily be 

expected do result in greater regulation in 

4~aur, Henry J. Private forest regulation: Cur- 1 

rent issues and future trends. Paper presented at 

the Western Forest Economists Heeting, Weme, I 

Oregon. Ha3 8, 1985. i I 

1 
California. Another explanation for the disparity 

in the two statesyorest practice legislation may 

be related to the extent of federal land holdings. 

The Vest Coast States have experienced extensive 

public ownership and public involvement in forest 

resources since 1900. This history has probably 

facilitated stricter state regulation of private 

forestry in the West than in the East since strict 

regulation is perceived as less onerous than public ownership. The debates during the 1960% over 

forest management sn private land also no dsubt 

helped set the stage for greater public regulation 

in the West (%lazar 1985). 

On the sther hand, the major force behind enactment sf the Massachusetts Fsrest Cutting Practices Act was the profusion of local ordinances 

restricting forestry operations. The same f~rce 

will probably result in the enactment of similar 

laws in other Eastern States. Furthermore, the 

Massachusetts law has been largely successful thus 

far and is generally supported by enviromental 

organizations, forest industry, local governments, 

and private landowners (~enl~ and Ellefson 1986). 

It therefore provides a viable model for other 

States in the region. Connecticut, Maine, New 

Jersey, Maryland, and Pennsylvania have all considered enactment of new or revised State forest 

practice legislation during the last few years. 

In the West, additional states may follow the 

lead of Alaska, California, Oregon, Washington, 

and Idaho in passing a comprehensive statute. 

Forest practice legislation was seriously considered by the Montana Legislature in 1985. 

Additionally, since the regulatory enviroment 

is a dynamic one, current laws will be revised 

periodically as society's goals for the management 

of forest resources change. 

The often opposing interests of environmental 

groups, forest industry, landowners and local governments are certain to result in conflicts as 

regulatory programs evolve or are revised. Ropefully, the outcome will be positive: well balanced 

laws which are technically strong and which require 

environmentally sound methods of harvesting and 

stand management at a cost which is not prohibitive 

for either forest landowners or the public. 

LITERATURE CITED 

Camichael, Donald %. Fee simple absolute as a 

variable research concept. Hatural Resources 

Journal I 3 5 (4) : 739-764; 1 975. 

Cubbage, Frederick W.; Ellefson, Paul V. State 

forest practice laws and regulations: a review 

and case study for Hinnesota. Station Bulletin 

536-1980. St. Paul, MN: University of Minnesota, 

1980. 42 pp. 

Cubbage, Frederick W.; Siegel, William C. The law 

regulating private forestry practices. Journal 

of Forestry. f83(9): 538-545; f 985. 

Green, Peter F,; Norbury, Frederick L.; Palley, 

garshall N.; Vaux, Henry J. Regulation of forest 

practices in California. Deparhent of Forestry 

and Resource Management, College of Natural 

Resources, University of California, Berkeley. 

198l- pp. 12 

Wenly, Russell K,; Eliefson, Paul V. Cost, administration and accomplisbents of sGate forest 

practice regulation in the U.S. Final Project 

Report, Cooperative Agreement, U.S. Department 

of Agriculture 42-418, Department of Forest 

Resources, University of Minnesota and State and 

Private Forestry, U.S. Department of Agriculture, Forest Service, 1986* gp. 160 

Hogan, Edward A. Catch 22 in New Jersey. The 

herican Tree Farmer. 3 (3) : 14-1 5 ; 1 984. 

Wuffman, James L. A history of forest policy in 

the U. 53, Environmental Law. 8 (2 ) : 239-280; 1978. 

Kauashima, Yasuhide; Tone, Ruth. Environmental 

policy in early America, a survey of colonial 

statutes. Journal of Forest History. 

27(4):168-479; 2983, 

Pasder, J, D, Money damages for regulatory 

" takingsQ*. Matural Resources Journal 

23(3):731-724. 1983. 

Salazar, De J. Political processes and forest 

practice legislation* Seattle; University of 

Washington; 1985. 234 p. Dissertation. 

Siegel, William C. State forest practice laws 

today, Journal of Forestry. 72 (4) : 208-21 6 ; 1974. 

Siegel, William C.; Cubbage, Frederick W- Eavironmental protection law and forest management 

regulations on private lands in the United 

States. In: Forestry Legislation -- Report of 

the IUFRO Working Party S4.06-84, pp. 140-156. 

International Union of Forestry Research Organizations, Zurich, Switzerland, 1984. 

Siegel, William 6,; Cubbage, Frederick W. Forestry 

legislative and regulatory trends--potential 

impacts for the hardwood resource. In: Proceedings of the thirteenth annual hardwood spposiwa; 1985 Hay 22-24; High Point, NC. Hardwood 

Research Council; 1985: PI 14-22. 

Vaux, Wenry J. State intervenkion on private 

forests in California. In: Sedgo, Roger A*, ed* 

Resources of the Future, Covermental interventions, social needs, and the management of U-S. 

forests; Uashington, DIG- 1983: 124-168. 
A Cone and Seed Cisease of Souther2 Pines Caused 

by the Pitch Cszker Fungus 

I 

In the southeastern United States, the bulk of 

seedlings for reforestation plantings by private 

industry and public forestry organizations come 

from seed orchards. At least 65 percent of the 

915 million seedlings produced ann6ally in this 

region are from geneticaily improved pines grown 

on 9,800 acres of seed orchards. Pitch canker. 

caused by Fusariun moniliforne Sheld. var, subglutinans ~ollenw. & Reink. (FHS), is one of the 

diseases that is rapidly increasing in importacce 

in seed orchards across the Southeast. Although 

seed orchard managers have noticed the disease for 

at least 25 years, the perceived insignificance of 

past outbreaks limited attempts to determine the 

causal agent. In 1975, however, the disease 

suddenly becane severe in two loblolly (Pinus 

taeda L.) seed orchards in separate regions of 

the South. Since then the pitch canker disease 

has been confirmed in more than 40 seed orchards 

(Dwinell and others, 1985; Kuhlman and others, 

1978). 

SYMPTOMS 

The two primary symptoms on vegetative structures are pitch canker and shoot dieback. Pitch 

cankers are characterized by a bleeding, resinous 

'presented at the Symposium "Current Topics in 

Forest Research: Emphasis on Contributions by 

Women Scientists"; November 4-6; 1986. Qniversity 

of Florida, Gainesville, FL 32511. 

'~esearch Plant Pathologist, Southeastern Forest Experiment Station, U.S. Departnent of Agriculture, Forest Service, Athens, GA 30602. 

-- 

Abstract,--The ?itch canker fenps, Fusariun 

noniliforme var. -- sub~lutinar~s (FlviS), causes 

se'sious darrage ir, pine s?eC orc:-izrds in ~he 

~outhe~~terz Usited Stztes. These orchards supply 

the zeneticzlly inproved seeds reqcired for 

replecticg harvested forest lznbs in this fezion. 

The saze pathoty~es of FPiS that cause synptorns opitch cazker on x~in stens: brenches, and shoots 

of souther6? ~i~es alocaGsp mortslity of reproductive structures on loblolly (Pines taeda) and -- P 

slash (P. zlliottii vdr. eiliottii) pines* the - 

two most econonically inportant southern pine 

species. The pattern of fungus isolation and 

hist~l~~gical data indicates that outbreaks of 

shoot diebscb and coce deterioration can occur 

independently In loblolly pine seed orchards. 

During the approximate IS-nonth period between 

production of female strobili and naturation of 

fully developed pine seed, there are potentially 

nuzerous op~ortunities for the causal pathogen to 

reduce seed yields. At this tine, determination 

of a complete disease cycle on ~ine reproductive 

structures awaits further investigation. 

Keywords: Shoot dieback, seed orchard nanagement 

histopathology. 

canker on the trunk or large branches of a tree. 

The canker is usually sunken and the bark is 

retzined, while the wood beneath rhe csnker is 

deeply pitch-soaked. Pitch--soaking of the under 

lying wood and the absence of swelling or callus 

help separate pitch canker from the other canker 

diseases of pine. 

The other symptom is shoot dieback in the upper 

croun. Lesions form on the late-sur;,ner flushes of 

growth; in autumn, fully developed needles turn 

yellow to reddish brown (fig. I). In the spring, 

new shoots may expand before they are killed by 

girdling of the older tissue. Witchesi broom 

develops in some trees when adventitious buds forr 

in response to repeated infection and dieback. 

Figure 1.--Canker formation on lateral shoots in 

the upper crown is a synptoc of shoot dieback. 
Several symptoms of FMS infection are observed 

on the pine reproductive structures. FMS causes 

the nortality of fenale flowers and nature cones. 

FMS-infected loblolly pine cones tend to be nisshapen and smaller than normal, and scales on 

green cones at harvest tine are resinous with 

purple discolortition. Xycelia of FNS are often 

present on outer surfaces of badly deteriorated 

lobloliy cones. Some infected cones have a 

necrotic tip characterized by internal pitch 

pockets. External resinous lesions colonized by 

FMS are also observed on som loblolly pine cones 

(fig. 2). 

Figure 3.--(A) Radiograph of noninfected seeds 

with garnetophyte and embryos intact. (B) Radiograph of infected seeds. Ganetophyte tissue is 

shrunken frori the seed coat and enbryo (arrows) 

appears slightly faded. 

CONE BARVESTING WOUNDS 

Figure 2.--(A) Loblolly pine cone infected with 

Fusariun noniliforme var. subglutinans (right) is ----- 

smaller and has fever viable seeds thin healthy 

cone (left). (B) Another symptom of infection is 

a terninal necrosis characterized by internal 

resin pockets (arrow). 

Preliminary observations on slash pine (P. pelliottii Engelrn. var. elliottii) -- indicate that 

the amount of infection in a given seed lot may 

vary from 0 to 98 percent. Internal loblolly 

pine seed tissues infected with FHS range from 

~otentially sound (based on radiography) to 

nummified. Radiographs (fig. 3) of many infected 

seeds show the ganetophyte shrunken fron the seed 

:oat and slight deterioration of the embryo. Other 

symptoms detected by radiography are dark circular 

areas in the seed tissues. Microscopic exaninatio? 

reveals a lack of cellular organization of the 

tissue and the presence of hyphae throughout the 

zeed (Barrows--Broaddus and Dwinell, 1985; Miller 

and Bramlett, 1978). 

Kost canker-producing organisms, including FMS, 

require a wound as an infection court. Host coneharvesting practices result in wounds to the trees. 

Subsequent pitch canker symptor:atology reflects 

rhe dizferent harvesting practices required by 

different pine species. For example, in loblolly 

pine seed orchards cones are us~ally harvested by 

tearing them off the branches. Shoot dieback 

symptomatology is most commonly observed in this 

species. Wounds in the upper crown caused by cone 

harvest may therefore exacerbate outbreaks of 

shoot dieback. 

Although loblolly pines generally recover from 

outbreaks of shoot dieback, at the height of an 

epidemic considerable loss of the cone crop may 

occur. The inpact of disease on cone yield, 

however, varies from orchard to orchard. For 

example, most of an 85 percent decline in cone 

yield in one loblolly pine orchard was attributed 

to shoot dieback, whereas in another loblolly pine 

orchard, cones initiated during an epidemic resulted in a record cone and seed crop. Damage assessment of shoot dieback should therefore include 

the relative susceptibilities of individual clones 

and their cone productisn his~ories, since both 

vary by genotype (Barrows-3roaddus and Dwinell, 

1385; Kuhlnan and others, 1982). 

In slash pine seed orchards, bole cankers ofterdevelop through injuries caused by mechanical 

shakers used in cone collection. The most obvious 

damage caused by tree shakers is the actual renova? 

of bark et the point where the pads grasp the bole. 

Cankers may also develop at grasp sites where there 

is no obvious bark removal. Pitch cankers frequently develop on the upper portion of the bole 

where the vibration (or whiplash) of the main sterr, 

is most vigorous. Some seed orchards have considered harvesting with nets as an alternative to 

harvest with tree shakers (Dwinell and BarrowsBroaddus, 1981). 
OTHER WOUSDS 

Any wound, regardless of cause or location, 

provides an infection court for the pathogen. In 

addition to cone harvest, routine seed orchard 

management practices such as branch pruning and 

nowing create wounds for the pathogen to invade. 

Weather-related injuries such as those from wind 

and hail may also serve as entry points. Hurricanes, tornadoes, and ice storm in recent years 

have caused intensification of pitch canker in at 

least two seed orchards. 

An array of insects feed on female strobili 

throughout their growth and maturation period, 

and possibly create infection courts for the 

pathogen. These insects may also transmit the 

pathogen into the cones. The deodar weevil 

(Pissodes -- -- nemorensis Germar) and the pine tip 

moth (Rhyacionia spp.) create wounds on shoots 

that may become infected by airborne spores of 

the pathogen. Deodar weevils, their associated 

galleries, and chip cocoons are frequently 

contaminated by FMS (Bramlett and others. 1977; 

Blakeslee and others, 1978). 

INOCULUM SOURCES 

Sporodochia of FMS occur routinely on infected, 

small-diameter branches. These fruiting bodies 

are found during all seasons of the year and are 

aost frequently located in fascicular scars. 

Sporodochia range from 1 to 3 mm in diameter and 

are a light salmon-orange color (sensu Ridgeway) 

(Blakeslee and others, 1978). Except for supporting conidiophores, the sporodochia normally 

contain only conidia (fig. 4). 

Figure &.--Sporodochium of Fusarium moniliforme 

var. subglutinans. 

Conidia of FMS are airborne, and maximum 

dispersal occurs during precipitation with turbulent air. The conidia are present throughout the 

year and can be recovered from dead branches in 

the crown, rainwater falling through infected 

trees, and from the air. FMS is also isolated 

from forest soils, surfaces of pine needles, 

branches, boles, and from bark and debris adhering 

to tree-shaker pads. Pathogenicity tests of these 

isolates on slash and iobloliy pines indicate that 

FMS occurs naturally in mixed populations of pathogenic and saprophytic strains. 

RELATIONSHIP BETWEEN 

SHOOT DIEBACK ASD CONE INFECTIOS 

Barrows-Broaddus and Dwinell (1985) studied an 

outbreak of shoot dieback in a loblolly pine seed 

orchard in South Carolina to determine the effect 

of shoot dieback on the conelets, cones, and seeds. 

- Disease Surveys 

In March 1983, ramets in the orchard were 

surveyed for shoot dieback and rated for disease 

severity by using the Kelley and Williams (1982) 

rating system. Twelve clones ranging from low 

(<I percent) to high (250 percent) disease incidence, were selected for sampling branches, conelets, and cones. In December 1883, another 

disease survey was conducted, and the 12 clones 

selected from the previous survey were rated 

again, based on new infections since March 1983 

(table I). The second survey in December 1983 

indicated that disease incidence declined for 7 

of the 12 clones, but the severity ratings for 

new infections among the clones matched those 

made in March (r = 0.80, = 0.01). This disease 

pattern in loblolly pine seed orchards has been 

observed by other researchers. 

Recovery of FMS from Samples 

In September 1983, 24 branches bearing 5-monthold conelets were randomly collected from each 

clone. In October 1983, 12 nature 19-month-old 

cones were randomly collected from each clone 

and subjected to standard cone analysis techniques 

(Bramlett and others, 1977). All samples including the seeds and scales from mature cones were 

cultured on Fusarium-selective media (Agrawal 

and others, 1973) and prepared for histological 

examination (Johansen, 1940). 

FMS was recovered from branches and conelets 

collected in September 1983 (table 2). Recovery 

of FMS from conelets in some clones was not 

correlated with recovery from the branches. 

Clone 6-1-515, for example, averaged 16.7 percent 

branches infected and 45.5 percent conelets 

infected with FMS. Conversely, 25 percent of 

the branches sampled from clone 6-1-575 were 

colonized by FMS, but FMS was not recovered from 

the conelets. 
Table I.--Average disease severLty rarings of shoot mortality 

cacsed by Fusariun conili:orme var. subglutinans on clones 

of loblolly pine in a seed orch&rds 

Ramets Yarch b Tf-ecenber 

- Clone (i"i . ) rating ratingC 

4.5 a 

3.0 b 

3.2 b 

3.0 b 

2,3 c 

2.3 c 

1.8 cd 

1 .S cde 

1.0 e 

1-13 e 

1*0 e 

1*0 e 

a~ive-point scale after K~lley znd Williams (1382): O = no 

disease, 1 = <I percent exhibiting dieback? 2 = 1-10 percent; 

3 = 11-20 percent; 4 = 21-50 percent; and 5 = >50 percent. 

Within columns, means not followed by the same Letter are 

significantly different :P = 0.01) according to Kramer9s 

(1956) extension of Duncan's mtltiple range test to group 

means with unequal numbers of replications (ramets). 

b~irst survey in March 1953; all current infections (wilted 

shoots with red needles) were counted. 

'second survey in December 1983; new icfections since March 

wore counted (needles on old infections had turned gray). 

Disease severity ratings were correlated with the Narch 

ratings (r = 0.80, I1 = 0-01). 

Table 2.--Recovery of Fusariun noniliforme var. subglutinans from 

branches and 5-mo:old conelets in 12 clones of lobiolly pine grown 

in a seed orchardd 

Branches Coneletsl Conelets 

infected branch Conelets infected 

C 1 one (avg %) (No. ) (No. > (avp, %) 

66.7 a 

65.8 

58.3 ab 

45.8 abc 

33.3 bcd 

25,0 cde 

16.7 de 

12.5 de 

4.2 e 

0 €? 

0 e 

0 e 

a~ased on 24 branches (replications) per clone. Means not followed by 

the sane let~er are significantly different (_El = 0.05) according to 

Duncan's mulriple range test. 
Histology of natural infections on branches 

looked similar to those previously described 

by Barrows-Broaddus and Dwinell (1983) on loblollq 

pine seedlings artificially inoculated with 

the pitch canker fungus. Conelets attached 

to infected branches became infected when the 

parenchyma connecting the conelet to the branch 

was colonized by the pathogen. The tissues 

of mature seeds colonized by FKS lacked cellular 

organization compared with tissues in noninfected 

seeds. Hyphae were observed in the enbryo 

cavity arid between the ganetophyte and the 

int egunen t . 

Results of this study demonstrated that outbreaks 

of shoot dieback may directly affect the developicg 

cones. There was evidence, however, that conelet 

deterioration could occur independently of 

shoot dieback. 

CONTROL STRATEGIES 

Because the pathogen requires a wound as 

an infection court, control recommendations 

in seed orchards concentrate on altering management 

practices to reduce wounding, especially during 

periods of high disease risk, primarily in 

the fall and winter. The use of tree shakers 

for cone harvest is discouraged; otherwise 

use trained personnel to properly adjust and 

operate then. Clip rather than tear loblolly 

pine cones to reduce stripping of the bark. 

Avoid mower damage to the tree stem and anchor 

roots. 

After cone harvest, if abnormal cones are 

not culled before seed extraction, it may be 

difficult later to separate infected seeds 

from noninfected seeds. Identification and 

culling of fu1;gus-damaged cones during harvesting 

operations could increase the percentage of 

seed germination. 

At this time, control measures are not available 

to prevent seed destruction by the pathogen. 

Irogress has been made at the Forestry Sciences 

Laboratory at Athens, GA, in identifying peak 

?eriods of susceptibility for developing cones. 

3etermination of a complete disease cycle, 

however, awaits further investigation. 

LITERATURE CITED 

Agrawal, S.D.; Khare, M.N.; Kushwara, L.S. A 

selective medium for isolation and quantitative 

estimation of Fusarium in soil. Science and 

Culture 39: 555-556; 1973. 

Barrows-Broaddus, J.; Dwinell, L.D. Histopathology 

of Fusarium moniliforme var. subglutinans in 

four species of southern pines. Phytopathology 

73: 882-889; 1983. 

Barrows-Broaddus, J.; Dwinell, L.D. Branch dieback 

and cone and seed infection caused by Fusariun --- noniliforne var. subglutisans - in a loblolly 

pine seed orchard in South Carolina. Phytopathology 75: 1104-1108; 1985. 

Blakeslee, G.Y.; Kratka, S.W.; Schmidt, R.A.; 

Moses, C.S. Sporodochia of the pitch canker 

fungus (Fusariurn noniliforne var. -- subglutinans) 

as Found in diseased slash pines in Florida. 

Plant Disease Reporter 52: 555-557; 1S78. 

Blakeslee, G.M,; Oak, S.W.; Gregory, W.; Moses, 

C.S. Natural association of Fusariun 

noniliforne var. subglutinans with Pissodes 

nemorersis (Abstract). Phyt&athoiogy News 

12: 208; 1978. 

Branlett, D.L.; Belcher, E.W.; DeBarr, G,L,; 

Hertel, G.D.; Karrfalt, R.P.; Lantz, C.W,; 

Miller, T.; Ware, K.D.; Yates, H.O. Cone 

analysis of southern pines. Gen. Tech. Rep. 

SE--13. U.S. Dep. Agric., For. Serv., 

Southeast. For. Exp. Stn. Asheville, NC: and 

Atlanta, GA: Southeast. Area, State and Priv. 

Forestry; 1977. 28 p. 

Dwinell, L.D.; Barrows-Broaddus, J.B. Pitch 

canker in seed orchards. In: Proceedings, 

15th Southern Forest Tree Icprovenent Conference; 

1981 Nay 27--28; Blacksburg, VA. Publ. 38; 

1382. 234-240. [Available from Forestry 

Sciences Lab, Carlton Street, Athens, GA 

30602 1. 

Dwinell, L.D.; Barrows-Broaddus, J.; Kuhlnan, E.G. 

Pitch canker: A disease complex of southern 

pines. Plant Disease 69: 270-274; 1985, 

I 

Johansen, D.A. Plant Microtechniques. New 

York: McGraw--Hill Book Co.; 1940. 523 p. 

Kelley, W-D.; Williams, J.C, Incidence of pitch 

canker anong clones of loblolly pine in seed 

orchards. Plant Cisease 56: 1171-1173; 1982. 

Kraner, C.Y. Extension of multiple range tests 

to group means wLth unequal numbers of replications. Biometrics 12: 307-310; 1956. 

Kuhlnan, E.G*; Dianis, Sell.; Smith, T. Epidemiology of pitch canker disease in a loblolly 

pine seed orchard in North Carolina. Phytopathology 72: 1212-1216; 1982. 

Kuhlman, E.G.; Dwinell, L.D.; Nelson, P.E.; 

Booth, C. Characterization of the Fusariuz 

causing pitch canker of southern pines. 

Mycologia 70: 1131-1143; 1978. 

Xiller, T.; Branlett, D.L. Danage to reproductive 

structures of slash pine by two seed-borne t 

pathogens: Diplodia gossypina and Fusarium & 

noniliforme var. subglutinans. In: Proceedings, 

~lowerin~and seed development in trees: A 

Symposium; New Orleans, LA: U.S. Dep. Agric. 

For, Serv., South. For. Exp. Stn., New Orleans, 

LA; 1978; 347-355. 
Insect Research in Great Plains windbreaks1 

Mary Ellen ~ix' 

Abstract.--Windbreaks are planted in the Great 

Plains to protect soil from wind and water 

erosion, to protect crops and livestock, to 

beautify and conserve energy on rural 

farmsteads, and to improve wildlife habitat. 

Although over 200 species of insects can damage 

trees in windbreaks, only a few species damage 

trees severely and adversely affect windbreak 

function. This review of forest entomology 

research in the Great Plains includes recent 

research accomplishments of the USDA Forest 

Service for several of the more destructive 

insect species. 

The Great Plains occupies approximately 

one-fourth of the continental United States land 

mass and extends from the Canadian prairie 

provinces to the Texas panhandle, and from the 

eastern Forests to the Rocky Mountains. It 

spans 1700 miles north to south and about 500 to 

800 miles east to west. The Great Plains is a 

major agricultural region, yet it is 

characterized by harsh, variable climatic 

conditions. Favorable conditions may be 

followed by intense heat, cold, drought, or 

hail. Temperatures in many areas range from 

below 0°F to over 100°F. At most locations, the 

wind seldom stops blowing (Griffith 1976). 

Until settlers arrived over a century ago, 

only Indians and a few trappers roamed the Great 

Plains. Today, nearly 94 percent of the land is 

occupied, with 33 percent agricultural crops; 56 

percent grasslands, range, and pastures; and 

less than 2 percent in trees (Griffith 1976). 

Before the arrival of the settlers, prairie 

fires, insufficient water, adverse weather 

conditions, extremely alkaline soils, and 

grazing by herbivores excluded most tree growth. 

Native grasses such as big bluestem, little 

bluestem, and buffalograss were the climax type 

of vegetation. Trees grew successfully only on 

sites with high water tables or on rocky slopes 

protected from the wind--river bottoms, woody 

draws, and sides of protected hills or buttes 

(Girard and others 1983; Tolstead 1947). 

The predominant native trees in the western 

Great Plains are species found in the western 

forests, such as Rocky Mountain juniper and 

'Current topics in forest research: Emphasis 

on contributions by women scientists. A 

national symposium. November 4-6, 1986. 

Gainesville, FL. 

*~esearch Entomologist, Rocky Mountain Forest 

and Range Experiment Station, Forest Service, 

U.S. Department of Agriculture, Lincoln, NE. 

Keywords: Shelterbelt, borer, defoliator, tip 

moth, seed-damaging insect, cankerworm, 

carpenterworm, metallic pitch nodule moth, ash 

seed weevil, seedbugs, coneworms, Zimmerman pine 

moth. 

ponderosa and lodgepole pines. Similarly, the 

predominant native trees on the eastern and 

northern edges of the Great Plains are hardwood 

species native to the eastern and boreal 

forests, respectively. 

The early settlers recognized the importance 

of trees in protecting humans, animals, and 

crops. As early as 1865 some states offered 

5 cer.ts per year and later $2 per year for each 

acre planted to trees. The Timber Culture Act 

of 1873 enabled homesteaders to obtain 160 acres 

of land by planting 40 acres of trees. Between 

1935 and 1942, over 200 million trees and shrubs 

in 18,600 miles of windbreaks were planted on 

30,000 farms in the Great Plains as part of the 

USDA Forest Service's Prairie States Forestry 

Project. These trees were planted to reduce 

wind erosion and desiccation and to provide 

relief jobs for the drought-striken population. 

The federal government furnished and planted the 

trees; the owners cultivated and protected them. 

In 1942 windbreak tree planting became the 

responsibility of the USDA Soil Conservation 

Service. Trees were planted on farms 

cooperating in a complete soil conservation 

program (Read 1958). Tree planting and 

maintenance costs were shared with the farmer. 

Some windbreaks planted since 1930 have been 

removed because of deterioration or conflicts 

with farm mechanization and central-pivot 

irrigation systems, higher land values, 

taxation, and improved crop varieties (Griffith 

1976). 

Currently, federal and state governments are 

actively promoting the renovation of existing 

windbreaks and the establishment of trees in 

farm, field, energy, and noise abatement 

plantings and as living snow fences. In 1985 

the Conservation Reserve Program was established 

by the U.S. Congress to promote soil 

conservation on highly erodible lands by 

planting trees and grass. 

Many tree species planted in the Great Plains 

performed poorly or failed because they were not 
adapted to the adverse climatic and site 

conditions, or because they were damaged by 

insects or diseases (Bruner 1890; Dahl 1940; 

Read 1958; Wilson 1962). Over 200 species of 

insects damage trees in the northern Great 

Plains (Stein and Kennedy 1972); additional 

species are common to the central and southern 

Great Plains. Most tree species planted in the 

Great Plains are susceptible to one or more 

serious insect pests; but, these insect pests 

usually are present in low numbers, do not kill 

the tree, and are not limiting factors to its 

survival. However, insect damage may reduce the 

protective value of trees. Wind protection to 

field crops, livestock, and homes can be reduced 

by defoliation or death of part of or an entire 

tree. In those areas of a planting where one or 

more trees are killed or damaged, wind 

velocities may be significantly higher than in 

surrounding undamaged areas. 

The role of insects in the failure of trees 

planted in Nebraska was recognized as early as 

1890 (Bruner 1890). Between 1910 and 1940 

forest entomology investigations in the Great 

Plains were conducted either by entomologists 

working for the USDA Bureau of Entomology or at 

the State Agricultural Experiment Stations. 

These investigations were limited to 

identification of insect pests and to life 

cycles and control studies on tip moths 

(Rhyacionia spp.) (Baumhofer 1932; Swenk 1927; 

Wygant 19361, carpenterworms (Prionoxystus 

robiniae (Peck)) (Munro 1939; Munro and Fox 

1934; Scholz 1935), spring cankerworms 

(Paleacrita vernata Peck) (Dean 1915), and 

several other insects that damaged trees in the 

Forest Service's Bessey Nursery near Halsey, NE, 

(Baumhofer 1932; Wygant 1936) or in tree 

plantings (Munro 1939; Scholz 1935; Severin 

1947, 1948; Ware 1936; Wygant 1938). During the 

1950's and early 1960's the Lakes States Forest 

Experiment Station was responsible for 

identifying species of tree insect pests in the 

Dakotas and for learning more about their 

biologies (Kennedy 1968; Kennedy and Wilson 

1969; Wilson 1962). In 1966 this responsibility 

was transferred to the Rocky Mountain Forest and 

Range Experiment Station, with research centered 

at Bottineau, ND. Responsibility was 

transferred to the Forestry Sciences Laboratory, 

Lincoln, NE, in 1981. 

During the 1960's and early 1970's tree insect 

pests and their natural enemies were identified 

(McKnight and Aahrus 1973b; Stein and Kennedy 

1972; Stein and Tagestad 1976) and biologies of 

major pest species such as elm sawflies (Cimbex 

americana Leach) (Stein 1974b), carpenterworms 

(P. robiniae) (McKnight 1973; McKnight and 

Tunnock 1973; Peterson 1964, 19711, lilac borers 

(Podosesia syringae (Harris))(Dix and others 

1978; McKnight 1973; McKnight and Tunnock 1973; 

Peterson 1971), cankerworms (Geometridae) (Stein 

1974a, 1974c, 1974d), and ash bark beetles 

(Lignyodes spp.) (McKnight and Aahrus 1973a) 

were documented Methods of sampling cankerworms, 

Kovner 1979; Dix and others 1979; Flavell and 

others 1978; McKnight and Tunnock 1973), lilac 

borers (Dix and Kovner 1979; Dix and others 

1979; Flavell and others 1978; McKnight and 

Tunnock 19731, and tip moths (Dix and Jennings 

1982; Van Haverbeke and others 1971). Since 

1975 the Forest Service has continued to 

document the biologies of major insect pests, 

and has developed techniques for the early 

detection, evaluation, and reduction of damage. 

Recent Forest Service research in the Great 

Plains has focused on the spring cankerworm fP. - - - vernata Peck (Lepidoptera:Geometridae)), the 

metallic pitch nodule moth (Retinia metallica 

(Busck) (Lepidoptera:Tortricidae)), the 

carpenterworm (41. robiniae 

(I,epidoptera:Cossidae)), the western pine tip 

moth (Rhyacionia bushnelli (Busck) 

(Lepidoptera:Tortricidae)), and the Zimmerman 

pine moth complex (Dioryctria spp. 

(~e~idoptera:~~ralidae)), and seed-damaging 

insects . SPRING CAPjKERW0RM.--Siberian elm (Ulmus pumila 

L.) is one of the few tree species that can 

survive the harsh environmental conditions of 

the northern Great Plains. This fast-growing, 

alkaline-tolerant, drought-resistant, coldhardy tree is commonly planted in field 

windbreaks and urban plantings. However, 

cankerworm larvae can severely defoliate these 

trees in the spring (Frye and others 1976). 

Damaged trees are unsightly and less vigorous 

than healthy trees.3 High winds may severely 

damage crops in fields adjacent to defoliated 

windbreaks. 

Spring cankerworms have a 1-year life cycle. 

Moths emerge and mate as soon as the soil thaws 

in March, April, or May. Females crawl up tree 

trunks and lay eggs under bark scales or in bark 

fissures. During May and June the eggs hatch 

and larvae feed on young leaves for about 3 to 6 

weeks before dropping to the ground where 

pupation and overwintering occur in the soil 

(Hildahl and Peterson 1974; Stein 1974a). 

Cankerworm damage can be reduced by spraying 

Bacillus thuringiensis (B.t.), carbaryl, or 

other insecticides on the leaves of elms 

infested with second instar larvae (Thompson 

1962; Frye and others 1976; Hard and others 

1979). Damage levels will remain low for at 

least 2 years after a single application of B.t. 

(Hard 1979). Although these insecticides are 

effective in reducing infestation levels, 

they are not used frequently in the northern 

plains because 1) they must be applied in the 

spring when farmers are busy planting, 

cultivating, and spraying crops; 2) aerial 

application is costly; and 3) at the time of 

3~i~, M.E.; Frank, A. Effects of artificial 

defoliation on growth and carbohydrate storage of 

Siberian elm. (Manuscript in preparation). r 

tip moths, and hardwood borers were developed, 

and insecticides were tested for control of 

cankerworms (Frye and others 1976; Stein 1969; 

Stein and Doran 1975), carpenterworms (Dix and 
application aerial applicators are busy spraying 

field crops. The planting of Siberian elm 

sources that are less preferred by cankerworms 

would provide an alternative method for 

minimizing damage (Dix and Cunningham 1984). 

During the late 197OVs, 160 Siberian elm trees 

that were less preferred by spring cankerworms, 

had superior morphological characteristics, or 

were disease resistant were identified in field 

windbreaks, A laboratory technique for 

evaluating cankerworm preference for clones of 

these trees has been developed, and five 

nonpreferred clones were identified with this 

technique, These clones were less preferred 

probably because of chemical or morphological 

characteristics of the leaves. Cankerworm 

preferences also will be evaluated in field 

plantings. Nonpreferred clones will be 

incorporated into a breeding program designed to 

produce genetically superior elm trees for 

planting in the northern plains. 

Several clones that were preferred by 

cankerworm larvae in laboratory trials escaped 

defoliation in windbreaks. These elms leafed 

out either earlier or later than most other 

elms. Leaves of trees that flush early are 

probably tougher and less palatable by the time 

newly hatched larvae begin feeding than those of 

other trees. Conversely, when egg hatch 

precedes bud break by several days, larvae must 

migrate to trees with leaves or risk starvation 

(Cunningham and Dix 1983). 

CARPEWTERWORM.--Larvae of carpenterworms 

tunnel into sapwood of hardwood trees throughout 

most of North America (Drooz 1985). In a 

survey of green ash (Fraxinus pennsylvanica 

Marsh) in North Dakota windbreaks in 1972, 28 

percent of plantings and 7 percent of the 

trees were damaged by carpenterworms (McKnight 

and Tunnock 1973). Detection and assessment of 

infestations is difficult and time consuming 

because the larvae tunnel into trees immediately 

after hatching. They feed and extend their 

tunnels within trees for 2 to 4 years before 

pupating in the tunnel. Several insecticides 

that are registered for control of 

carpenterworms kill young larvae before they 

mine into trees. However, timing of application 

is difficult, because the initiation and 

duration of moth flight and egg hatch, which are 

dependent upon seasonal temperature can vary by 

as much as 4 to 6 weeks (Dix and Kovner 1979; 

NcKnight and Tunnock 1973). For these reasons, 

a method of detecting and assessing infestations 

with attractants was developed. 

The male attractant (5,g)-3,s-tetradecadienyl 

acetate (Z3,E5-14:AC) was isolated and partially 

characterized by Solomon and others (1972) and 

Doolittle and others (1976). A trapping 

technique using this attractant was developed by 

evaluating the effect of trap design, 

'~ix, M.E., USDA Forest Service, Rocky 

Mountain Forest and Range Experiment Station, 

Lincoln, NE.; and Cunningham, R., USDA 

Agricultural Research Service, Northern Great 

Plains Research Center, Mandan, ND. (Unpublished 

data) . 

attractant dispenser, attractant release rate, 

isomer ratio, and trap placement on catches of 

carpenterworms in native stands and plantings. 

Traps with ~onrel' hollow fiber dispensers 

releasing 36, 54, or 72 gg of Z3,E5-14:AC per 

day caught more males for a significantly longer 

period of time than traps with wick dispensers 

baited with 36 vg of attractant. Traps with 

septa dispensers caught males for the entire 

moth flight. Addition of antioxidants to extend 

the length of attraction increased the efficacy 

of wick dispensers, but not the efficacy of 

fiber or septa dispensers. Netal-cylinder, 

milk-carton, and cardboard-cylinder 

type traps all caught large numbers of males; 

however, the cardboard-cylinder traps were the 

most economical to construct, least messy to 

handle, and the easiest to store. The largest 

number of males were caught in traps hung 

between 1.5 m and 6 m high and at sites with 

moderate or light undergrowth (Doolittle and 

others 1976; Solomon and others 1978; Dix and 

others 1979, 1984, 1987; Dix and Doolittle 

1984). Hollow fiber dispensers baited with the 

Z3,E5-14:AC are now commercially available. 

METALLIC PITCH NODULE MOTHS.--Larvae of 

metallic pitch nodule moths mine the buds and 

growing tips of pines, especially ponderosa pine 

(Pinus ponderosa Dougl. ex Laws.). Infested 

branches are stunted, and branch tips are 

frequently killed (Van Deusen and Dix 1980). 

Metallic pitch nodule moths prefer pine sources 

from the northern and central Great Plains and 

northern Rocky Mountains that are taller than 

1.5 m (Van Deusen and Dix 1980). During the 

past 10 years the number of windbreaks in the 

northern and central Great Plains infested with 

the moth and the number of infestations within a 

windbreak have been increasing. This 

corresponds with the increased use of ponderosa 

pine in windbreaks and subsequent growth of 

these pines. 

Metallic pitch nodule moths have a 1-year life 

cycle. In Nebraska, moths usually emerge during 

early May and lay eggs on the new growth. The 

solitary larva tunnels into new growth and buds 

during summer. During July a pitch nodule or 

round pinkish mass composed of pitch, sawdust, 

and insect excrement is formed over the initial 

point of attack. The larva overwinters within 

its tunnel and pupates in early spring (Dix 

1985; Dix and others 1987). Biological data 

needed to develop and validate a simple life 

cycle model for the moth are being researched by 

Dix. 

One spring application of carbaryl, applied 

immediately after moth flight and before larvae 

tunnel into stems, can reduce the proportion of 

ponderosa pine branches that become infested and 

also the number of infestations per branch. 

'Mention of proprietary product or service 

does not constitute an endorsement by the U.S. 

Department of Agriculture. 

7~ix, M.E. USDA Forest Service, Rocky Hountain 

Forest and Range Experiment Station, Lincoln, 

NE, (Personal observation). 
Timing of the insecticide application is 

crucial, because carbaryl is ineffective if it 

is applied early in moth flight or during peak 

flight (Dix 1985) . Synthetic attractants of male moths can be 

used to successfully time insecticide 

applications and to detect infestations. \%%en 

responses of male moths to traps baited with a 

series of known synthetic attractants of male 

tortricids and related compounds were compared, 

several compounds appeared promising, but an 

attractant could not be positively identified 

because male response varied with site and year 

(Dix and Jacobson, in press; Dix and others 

1984). For this reason, Dix and Underhill used 

electroantennography to identify an attractant. 

This attractant has been successfully field 

tested in Nebraska. 

WESTERK PINE TIP MOTH.--This insect has caused 

extensive damage to young pine trees in the 

central and northern Great Plains since it was 

first observed at Bessey Nursery in 1909. 

Larvae mine into young needles and buds, causing 

reduction in growth and deformation of branches 

and leaders. Young trees may die following 

repeated severe infestations. 

Both systemic and contact insecticides are 

registered for control of moths. Application of 

contact insecticides must be timed to coincide 

with egg hatch, and early application is 

critical. The insecticides must kill the larvae 

before they bore into the bud where they are 

protected. Seasonal variations in -the rate of 

development of the pine tip moth make a fixed 

application schedule ineffective. Methods of 

timing insecticide applications from plant 

phenology observations and degree-day 

accumulations currently are under study. 

ZImERmN PINE MOTH COMPLEX.--Larvae of 

~onderosa twig L, moths {Diorvctria ~onderosae 

Dyar), g. tumicolella Mutuura Monroe and Ross, 

and Zimmerman pine moths (2. zimmermani (Grote)) 

mine under the bark of ~onderosa iP. 

ponderosae) , Austrian (Pinus nigra-~rnold) , and 

Scotch pines (P. sylvestris L.), girdling 

branches and trunks. Infested branches often 

bend downward or break off at the main stem, 

especially after heavy snow or during high winds 

(Harrell 1984). Ponderosa twig moths and D. 

tumicolella damage trees throughout Nebraska, 

while Zimmerman pine moths are found only in 

extreme eastern Nebraska. The life cycle of 

ponderosa twig moths takes 14 to 24 months to 

complete, while those of 2. tumicolella and 

Zimmerman pine moths last approximately 1 year 

(Harrell 1984, 1986a). g. tumicolella damage 

can be reduced by applying acephate as a stem or 

8~ix, M.E.; Underhill, E.W. Sex attractant of 

Retinia metallica (Busck) 

(Lepidoptera:Tortricidae): Identification and 

field studies. (Manuscript in preparation). 

'~asek, J. Research Entomologist, Rocky 

Mountain Forest and Range Experiment Station, 

Forest Service, U.S. Department of Agriculture, 

Lincoln, NE. 

trunk implant, dimethoate as a stem drench, or 

disulfoton as a soil drench, in early April 

before first instar larvae bore into the trunk. 

The number of first instar ponderosa twig moth 

larvae and older D. tumicolella larvae 

can be reduced by-applying acephate or 

dtmethoate at 2-week intervals in mid-summer 

(Harrell 198hb, 1986~). 

SEED-DWGING INSECTS.--Insect damage to seeds 

of conifers and hardwoods in the Great Plains is 

a major concern in seed production areas, in 

genetically superior stock, and in research 

programs to improve trees. The western conifer 

seedbug (Leptoglossus occidentalis Heideman) can 

destroy up to 80 percent of the seed of 

ponderosa and Scotch pines; ash seed weevils 

(Lignyodes spp.) can destroy up to 90 percent of 

the green ash and lilac seed (Dix 1986). 

Forest Service entomologists have identified 

insect species that damage ponderosa pine, 

Scotch pine, and green ash, and some insect 

species that damage other conifer and hardwood 

trees. Dix (1986) determined that lilac is an 

alternative host for the ash seed weevil. 

Detailed information on life cycles and impact 

of damage on seed yield is available for only a 

few of these species. Aspects of the life 

cycle, behavior, and seasonal abundance of the 

western conifer seedbug and the ponderosa pine 

coneworm (Dioryctria auranticella Grot&), and 

the effect of insect damage on seed yield are 

being studied. Effective techniques for 

control of most seed-damaging insects in the 

Great Plains are not available. Laboratory 

analyses of acephate in Scotch pine cones 

indicate that acephate residues should kill 

webbing coneworm (D. disclusa Heinrich) larvae 

for 10-15 days after spraying (Dix and others 

1981), but this needs to be verified in the 

field. Carbofuran, an insecticide used to 

control seed-damaging insects in the south, was 

ineffective in reducing webbing coneworm and 

western conifer seedbug damage to Scotch pine 

seeds in Nebraska and Korth Dakota (Dix and Van 

Deusen 1983). 

SUWRY.--In summary, trees growing in 

windbreaks and native stands are essential 

components of the Great Plains environment. 

However, many trees perform poorly or die 

because of adverse climatic and site conditions 

and damage from insects and diseases. Forest 

Service research is improving tree performance 

by selecting and breeding genetically improved 

sources of trees and developing methods of 

reducing insect injury to trees. Entomology 

research has collected biological information 

and developed techniques for-detecting, 

evaluating, and reducing damage for some of the 

most destructive insect species. Further 

research should refine these techniques, develop 

new techniques, and obtain the biological data 

needed to effectively manage infestations of and 

damage by several important seed-damaging 

insects and tip borers. In addition, insects 

that damage the seeds of spruce, honeylocust, 

and pines need to be identified and their effect 

on seed production assessed. The most 

destructive of these seed-damaging insects can 

then be targeted for additional research. This 
research should result in additional guidelines 

for reducing insect damage to trees that can be 

integrated into managements plans for future 

planting s in the Great Plains. 

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Stein, John D. Elm Sawfly. Forest Pest Leaflet 

142, Washington, D.C.: U.S. Department of 

Agriculture, Forest Service; 1974b. 6 pp. 

Stein, John D. Spring cankerworm (Paleacrita 

vernata) (Lepidoptera: Geometridae) feeding on 

flax as a secondary host. Canadian Entomologist 

LOS:?83-784; 1974~. 

Stein, John D. Unusual oviposition sites of 

Paleacrita vernata. Journal of the Kansas 

Entomological Society 47(4):483-485; 1974d. 

Stein, John D.; Doran, Dennis. A nondestructive 

method of whole tree samplings for spring 

cankerworm. Res. Note RM-240. Ft. Collins, CO: 

U.S. Department of Agriculture, Forest Service, 

Rocky Xountain Forest and Range Experiment 

Station; 1975. 4 pp. 

Stein, John D.; Kennedy, Patrick C. Key to 

Shelterbelt Insects in the Northern 

Great Plains. Fort Collins, C0.: Res. Pap. 

EM-85. U.S. Department of Agriculture, Forest 

Service, Rocky Mountain Forest and Range 

Experiment Station; 1972. 153 pp. 

Stein, John D,; Tagestad, Arden. The long-horned 

wood-boring beetles of North Dakota 

(Co1eoptera:Cerambyeidae). USDA Forest Service, 

Research Paper Rlvl-171, Ft, Collins, CO: U.S. 

Department of Agriculture, Forest Service, 

Rocky Mountain Forest and Range Experiment 

Station; 1975, 58 pp. 

Swenk, H,W. The pine tip moth in the Nebraska 

Xational Forest. Res. Bull. 40,Lincoln, NE. 

University of Nebraska, College of Agriculture, 

Agricultural Experiment Station; 1927. 50 pp. 

Thompson, B.E. Effect of delayed spraying on 

cankerworm control. Journal Economic 

Entomology 55:558-559; 1962. 

Tolstead, W.L, Woodlands in Northwestern 

Nebraska. Ecology 12:2:180-188; 1947. 

Van Beusen, James L.; Dix, Mary Ellen. A survey 

of Petrova metallica (Busck) in a South Dakota 

ponderosa pine provenance test plantation 

(Lepidoptera: Tortricidae: Olethreutinae). 

Journal of the Kansas Entomological Society 

53:652-668; 1980. 
Van Haverbeke, David F.; Roselle, Robert E.; 

Sexson, Gary D. Western pine tip moth reduced 

in ponderosa pine shelterbelts by systemic 

insecticide. Res. Mote RM-194. Ft. Collins, 

CO: U.S. Department of Agriculture, Forest 

Service, Rocky Mountain Forest and Range 

Experiment Station; 1971. 7 pp. 

Ware, E.R. Planting and care of trees in South 

Dakota. South Dakota College Extension Circular 

356; 1936. 56 pp. 

Wilson, L.F. Grasshoppers--a major defoliator of 

trees and shrubs in the northern Great Plains. 

Tech. Note 596. St. Paul, m: U.S. Department 

of Agriculture, Forest Service, Lake States 

Forest Experiment Station; 1962. 27 pp. 

Wygant, N.D. Insect control in shelterbelts on 

the Great Plains. U.S. Department of 

Agriculture, Agricultural Research 

Administration, Bureau of Entomology Plant 

Quarterly; 1936. 51 pp. 

Wygant, N.D. The relation of insects to 

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Journal of Forestry 36(LO):1011-1018; 1938. 
HORMONAL REGULATION OF MNCORRHIZA~ 

Nada (20gala2 

The laboratory of plant physiology at the 

University of Ljubljana is mainly devoted to the 

investigation of hormonal regulation in mycorrhiza. 

It was determined that fungi influence with 

growth substances the development of the root 

system and growth of green plants on degraded soil. 

On the other hand, the tree with its growth substances in the root and in the exudate influences 

the growth and metabolism of the mycelium. 

In the root exudate of the scotch pine Pinus 

sylvestris we found a11 growth stimulators-- 

auxins, gibberellins and cytokinins and the inhibitor abscisic acid (ABA). Cytokinins at concentration of about 10-7 g/ml are stimulators of 

fungal growth, while at suptraoptimal higher 

concentrations inhibit it (Fig. 1) . 

Figure 1. --Influence of various growth substances 

on growth rate of the fungus Suillus variegatus. 

Fresh weight of mycelium after 2 weeks of growth, 

lpresented at the Symposium on Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists, November 4-6, 1986, Gainesville, 

FL. Co-sponsored by the USDA Forest Service, 

Southeastern Station, and the University of Florida. 

2~rofessor, Institute of Biology, University of 

Ljubljana, Yugoslavia. 

expressed in percentage of control values 1100%) 

at different concentrations of growth substances 

in medium. 

Gibberellins inhibit growth, indole acetic acid 

(IAA) does not have a significant influence, but 

together with cytokinins work synergistically. 

ABA is without effect, while JA (jasmonic acid) 

is a very strong inhibitor. We think that the 

relation of the growth substances in the exudate 

and in the roots is very important for normal 

growth of the mycelium around the roots and between the cells of rhizodermis. 

We also investigated the influence of some 

environmental factors on the exudation of 

cytokinins and gibberellins from pine trees, 

Young seedlings of Pinus sylvestris were cultivated in bidistilled water in growth chambers at 

different photoperiods, different light intensities and three different temperatures. After 6 

days of treatment cytokinins and gibberellins 

were extracted and analyzed by paper and column 

chromatography and tested with bioassays. According to our results we can claim that the amount 

of cytokinips and gibberellins increases with 

increasing length of the daylight phase. Light 

intensity does not affect the exudation of 

gibberellins, but the effect on the exudation of 

cytokinins is obvious. There were more cytokinins 

in the exudate at higher light intensities (Fig.2) . 

Figure 2.--Influence of light intensity on the 

exudation of cytokinins and gibberellins from 

red pine seedlings. 1: relative amounts of 

gibberellins at different light intensities, detected with the endos~erm bioassay, 2: relative 

amounts of cytokinins in the water phase, and 

3: the same in a buthanol phase, detected with 

the radish cotyledon bioassay. 

Similarly temperature did not influence 

gibberellin exudation and the optimal temperature for the exudation of cytokinins was 

22O C. (Figs. 3 and 4 .) 
Figure 3,--Influence of photoperiod on the 

exudation of phytohormones. 1,2: relative 

amounts of gibberellins at different daylength, detected with the endosperm bioassay. 

Exudates from pine seedlings of two provenances. 3: relative amounts of cytokinins 

in the water phase and 4: the same in the 

buthanol phase, detected with the tobacco 

tissue assay. 5: Cytokinins, detected by 

haranthus hypocotyl assay. 

Figure 4.--Influence of temperature on the 

exudation of phytohormones. 1: relative 

amounts of gibberellins at different temperatures, detected with endosperm bioassay. 

2: Cytokinins detected with Amaranthus 

hypocotyl assay. 

Our conclusion is that only certain comb inat ions 

of environmental conditions such as a long day 

regime, higher light intensities and optimal 

temperature bring about such a combination of 

hormones in a rhizosphere, which promotes 

mycelium growth and the formation of mycorrhiza. 

Plant hormones, mainly cytokinins in the exudate influence the uptake of ions, e. g, sodium, 

calcium, potassium and phosphorus, into the 

mycelium. During the first days after inoculation cytokinins are responsible for a decreasing 

content of elements in the mycelium but later, 

after 15 days of growth, there is an evident 

increase in uptake. 

On the basis of this and previous papers we 

can generalize that cytokinins from the root 

exudate of higher plants may influence the 

growth of fungi and regulate the uptake and 

distribution of important elements in the 

mycelium of mycorrhizal fungi (Fig. 5). It is 

still unclear how cytokinins influence the cell 

membrane. To clarify this question EPR (electron 

paramagnetic resonance) was used to measure the 

fluidity of the membrances with and withouc the 

cytokinins (Fig. 6). Mycelium was grown in the 

standard medium. During growth zeatin was added 

to the medium. After 14 days the mycelium was 

spin labeled with a nitroxide derivative of 

pal~itic acid methylester JMeFASL) . The results 

show that zeatin at concentrations of 10-6 nolil 

produces a slight decrease in membrane fluidity, 

but at a concentration of approximately 10-3 mol/I 

the flcidity of the membranes increases. 

The observed changes in mernbrane fluidity might 

be connected with changes in ion transport 

mechanisms and/or binding properties of the 

membranes. 

The influence of cytokinins on the growth of 

fungi is connected with the concentration of 

minerals in the medium. In a medium poor in 

minerals the effect of cytokinins is more 

pronounced. 

On the other hand, we are also investigating 

the influence of hormones from the mycelium on the 

growth of trees and their roots. Auxins are 

very important for the formation of mycorrhizal 

roots. iJe found IAA and TR (tryptophan) as its 

precursor in all mycorrhizal fungi, but not at 

the same concentrations. We therefore decided 

to extract these auxins from the fungus, and to 

treat tree cuttings with them in order to improve rooting. Good results were obtained when 

Acer pseudoplatanus was treated with auxins from 

Lycoperdon species. 

With increasing air and soil pollution, investigation of mycorrhiza becomes more and more 

important in forestry. Mycorrhizal fungi aceumulate heavy metals. Various species of fungi do 

not accumulate the same metals and not in the 

same concentrations. We can therefore find more 

Cd in the mycelium of Suillus variegatus as in 

Amanita muscaria or Boletus edulis. The growth 

of mycorrhizal fungi is inhibited by heavy 

metals as, for exam~le, Zn, Cd, and others. 

For practical purposes we are also investigating the effects of fungicides and herbicides 

used in nurseries. The use of these chemicals 

at too high concentrations in agriculture and 

forestry is problematic, since it influences not 

only parasitic fungi and weed plants, but they 

also inhibit the growth of symbiotic microorganisms. Herbicides in general are strong 

inhibitors of growth of the mycorrhizal fungi 

-- Boletus bovinus and Suillus variegatus (Fig. 7). 

At the concentrations used in nurseries they 

completely inhibit the growth of the mycelium. 

We tested "Roundup, " ramox ox one, 'hnd "Basamid. " 

The fungicides "Benornil, " "Captan, " and 

"Cuprablaul' also inhibit fungal growth (Fig. 8) . 

With the use of tissue culture we are able to 

investigate the influence of mycorrhizal relationships in vitro. We tried to stimulate with 

fungal metabolites the axillary buds of the 

seedlings of Pinus sylvestris and adventive buds 

from embryoes in vitro. Some influence on the 

axillary buds was observed, but we think that 
""L-.-- - 0 6 10 13 17 20 24 27 days 

""I / '\, 4 

growth 0 6 10 13 17 20 24 27 

Figure 5 .--The influence of aeatin mol/l) on the ion transport into and through 

mycelium of Suillus variegatus x-x: Concentration of ions in mycelium, o---a: concentrations of ions in medium. 

SU~LLUS VARIGATUS + MeFASL (10,3) 

o a o CONTRCL 

. . . ZEATlN 4,65x ldtmol /i 

Figure 6.--The change of membrane fluidity of fungal hyphae after treatment with zeatin, 

measured as correlation time of PleFASL at different temperatures. 
Figure 7 .--Fresh weight of mycrliiim of Suillus variegat~s (S.V.) and -- 

Bol~t~~s hovintls (B .b.) 

cultivated in medium at va rioui concent rations ilf fungi~ ides and herbicides Roundop, Gramaxone, 

and Basamid. 

Figure 8.--Fresh weight of mycelium of Suillus variegatus (s.v.) and Boletris bovinus (B.b.1 

cultivated in medium at various concentrations of the fungicides Benonil and Captan. 

other species should be tested with higher concentrations of natural growth substances. 

BAP (benzyl -amino -pur ine) gave us the best 

results. The best initiation of buds was obtained wtih seedling apexes soaked in SAP for 

3 hours. Buds longer than I mm were separated 

and elongated by far-red light. Elongated buds 

and shoots were treated again with BAP which 

resulted in the initiation of secondary buds or 

were rooted with MAA (napthalene acetic acid), 

IAA or IBA (indole butyric acid). 

We hope that in the next months the form- ation 

of mycorrhiza will occur. In such a way we 

sould like to get the mycorrhizal trees for 

afforestation on nutrient depleted or eroded 

land. 

An interesting new approach is the stimulation 

of myceiia with weak DC electric currents, 

similar to those, normally uroduced by both 

fungal byphae and plant roots. Significant 

differences in fresh and dry weight (85% and 50%, 

respectively) , reflect a drastic growth rate 

enhancement of the stimulated mycelia. The 

The highest rooting percent (64%) was obtained effect was observed regardless of whether 

with treatment with 54 pm SAA, Rooted shoots chloridised silver or stainless steel elecand plantlets were placed in a substrate with trodes were used, Changes in the pattern of 

or without the mycelium of Pisolithus tinctorius, ion accumuLation were found, with increases in 

After two months the stimulative effect of the calcium and potassium content and decreases in 

mycelium was evident (Fig, 9). sodium and phosphorus content. 
Figrrre 9,--Plantlets of Pinus sylvestris two months after planting in substrate with 

mycelium of Pisolithus tinctorius (above) or without it (below). 

In conclt~sion, our work is aimed at elucidating the importance of this form of symbiosis for 

various aspects of mycorrhizal relationships and forest ecosystems. 
ELISA Applied to Forest Pathology 1 

Pauline 6. Spaine 2 

HISTORY OF THE DISEASE AND DISEASE 

RESISTANCE SCREENIEG EFFORTS 

Fusiforn rust, caused by the fungal pathogen 

Cronartiun quercuun (3erk.) Hiyabe ex Shirai f. 

sp. fusiforne (Cqf), is the most economically 

destructive disease in pine plantations in the 

Southeastern U.S. Annual losses to the disease 

exceed 130 million dollars annually (Anderson 

and others, 1982). The disease causes tremendous 

losses in nurseries, young plantations and seed 

orchards. The highest percentage of mortality 

from the disease occurs in seedlings and young 

trees less than 8 years old (Agrios 1978; 

Czabator 1971). 

Control of fusiforn rust in forest tree nurseries 

relies primarily on fungicide spraying of the 

seedlings in nursery beds (Schmidt and others, 

1981). The most economical and long-term control 

of fusiform rust in field plantings is to increase 

the level of resistance to Cqf in the pine population through breeding and selection (Czabator 

1971; Dinus and others, 1976; Jewel1 1960). 

Screening for disease resistance in the field 

depends upon an assessment of both the incidence 

and severity of the disease. These field tests, 

however, require a minimum of 4 to 5 years for 

i Presented at the Symposium .'Current Topics in 

Forest Research: Emphasis on Contributions by 

Women Scientists"; November 4-6, 1986. University 

of Florida, Gainesville, Fl 32611. 

'Research Plant Pathologist, Southeastern Forest 

Experiment Station, U.S. Department of Agriculture, 

Forest Service, Athens, GA 30602. 

Abstract.--The enzyme-linked immunosorbent assay 

(ELISA) is a immunochemical test that can be 

designed to both detect and relatively quantify 

the amoGnt of mycelium in a host plant. ELLSA 

is therefore a rapid and sensitive procedure for 

detecting plant pathogens. Two procedures, the 

indirect and indirect preabsorption ELISA were 

used to detect Cronartium auercuum f. s~. 

fusiforme (6qf) in -- Pinus taeda seedlings. Detection of Gqf homogenates with the indirect ELISA 

was possible wi~h fungal fresh weights as low as 

20 vgjml. However, when the indirect ELISA was 

applied to detect Cqf homogenates nixed with 

healthy tissue (simulating an infection situation) 

binding efficiency was decreased and detection 

levels were lowered. For further testing of 

P 

Cqf-infected _El. taeda seedlings, the indirect 

preabsorption ELISA was designed to eliminate 

the interference from healthy plant homogenates 

in binding to the ELISA plates. This assay 

eliminated the interference from healthy plant 

honogenates and maintained a high sensitivity 

for Gqf detection. 

Keywords: ELISA, Cronartiun, fusiform rust, 

resistance screening. 

evaluation of new plantings. Greenhouse screening of Pinus elliottii Engelm. var. elliottii 

seedlings at the USDA Forest Service Resistance 

Screening Center maintained by Forest Pest Management in Asheville NC, can provide resistance 

ratings as early as 4 to 7 months after inoculation 

with Cqf basidiospores. Screening center ratings 

based= gall and infection characteristics of 

greenhouse inoculated seedlings are closely 

correlated with field resistance. 

Early infection of _F". elliottii tissues by Cqf I 

in some cases produced necrotic responses that 

were thought to limit fungal growth* and were 

observed to occur with increased frequency in a 

resistant family line (Miller and others, 1976). 

Using light and transmission electron microscopy, 

Gray and Amerson (1983) observed several responses 

of P. taeda L, to Cqf infection as early as 36 

hours zfter in vitro inoculation with Cqf 

basidiospores. In three P. taeda families 

examined, all displayed a necrotic response: but, 

the resistant family developed cell and tissue 

necrosis more rapidly than families rated as 

susceptible or intermediate in disease resistance, 

Frampton and others (1983). working with 24 fullsib families of P. taeda seedlings inoculated 

-- in vitro with Cqf, observed various characteristics 

of two phenotypic responses. These responses, 

a rapid necrosis and the appearance of a dark 

staining substance seen 7 days after inoculation, 

were highly correlated with families having low 

disease resistance ratings in the field. 

Most in vitro studies examining early rust i 

resistance have been done via nicroscopy. These I . . 

assays are tedious, and assessment and ~rading 

scales nay differ subjectively from one lab to 

the next. During the last 5 years, however, 

sensitive serological techniques such as enzyme- L 

i 
linked immunosorbent assays (ELISA) have made it 

possible to detect pathogens in plants in nanogram and picograin quantities (Van Regenmortel1982; Yolken, 1978). ELISA is an objective and 

quantitative method that sllows large numbers of 

specimens to be examined rapidly. Recently 

investigators have used ELISA to detect fungal 

pathogens such as Verticilfiun lecanii in wheat 

(Casper and others, 1979) and Epichloe typhina in 

tall fescue (Johnson and others, 1982)- ELISA 

has also been used for the quantification of 

enzymes in fungi (Martin and others, 1983). In 

the area of forest pathology, Gooding and Powers 

(1965) using serological techniques, were able to 

differentiate between 3 closely related tree rusts 

This paper will describe two versions of an ELISA 

for the detection of fusiform rust. These assays 

were compared for the detection of _C& from axenic 

cultures, and secondly for the detection of 

mycelial growth in P. taeda seedlings. 

I. &q& sample antigen 

is adsorbed to we1 l 

r 2 Add C.a.f. antibody 

3. Add enzyme-labeled 

antibody specific for 

first antibody 

4. Add enzyme substrate 

for a colorimetric 

reaction 

ELISA 

Figure 1. The Indirect ELISA 

Enzyme-linked immunosorbect assay (ELISA) is a 

diagnostic technique which has emerged over the 

last decade, and is based upon immunological 

principles. Inmunoassays such as ELISA rely on 

the specific binding that can occur between 

antigens (foreign substances) and antibodies made 

against those antigens (Cunninghan, 1978). 

Experimental observations made in 1971 recognized 

that when an antigen or antibody is chenically 

(covalently) linked to an enzyne, the resulting 

conjugate retains both its immunological and 

enzymatic activity (Koenig and Paul, 1982; Yolken. 

1978). Antibodies or antigens labeled with various 

markers have been found to be particularly useful 

for assays of biological substances (Savage and 

Sall, 1981; Voller and others, 1980) as in an 

ELISA. The label can be an isotope (radioimmunoassay), a florescent molecule (floroimmunoassay; 

or an enzyme (ELISA) giving increased sensitivity 

in detecting the antigen--antibody reaction (Voller 

and others, 1980). 

There are numerous versions of ELISA (Koenig and 

Paul: 1982; Van Regenmortel, 1'382), each being 

modified slightly for the system to which it is 

applied. Illustrated here are the two versions 

of ELISA discussed in this paper (Figures 1 and 

2). 

HEALTHY INFECTED 

I. Incubate healthy and 

Q& infected samples 

with antibody 

2. Adsorb -& coating 

antigen to well 

rurrfaerr 

3 Unprtcipitated 

antibody is placed 

into mated we l Is 

4. Add mwe-labeled 

ant1 bdy specific for 

first antibody 

!5. Add enzyme substrata 

for a e~forimetric 

reaction 
In the indirect ELISA (ID) (Figure I), the 

antigen (pathogen) is coupled to the plate, thec 

tbe antibody that was produced against the antige~ 

(primary antibody) is added. In the next step, 

after incubation and washing, a secondary antibody 

(goat anti-rabbit), that has been conrrercially 

conjugated to an enzyme is added to the plate. 

In the indirect preabsorption ELLSA JIPA) the 

inoculated and healthy samples are incubated with 

primary antibody in separate tubes before adding 

then to the ELISA plate (Figure 2). Subsequent 

steps follow as in the indirect ELISA. 

The final step in the above ELISAs is the 

addition of substrate. The enzyne label conjugated 

to the antibodies will catalyze the reaction of 

substrate to product, yielding a colorimetric 

reaction. The amount of colorimetric product is 

dependent on the quantity of antigen that was 

originally present in the test sanple. 

MATERIAL AND METHODS 

Pinus Taeda Inoculations ---- 

Basidiospore inoculum was collected according 

to method I1 (Amerson and others, 1985). Leaves 

of -- Quercus rubra L. bearing telia were suspended 

in a moist chamber over sterile acidified distilled 

water (pHz2.2) for 36 hours. The water was 

collected and the basidiospores we?e concentrated 

on a 5 ym millipore filter. Spores were resuspended in distilled water (pH=5.5), and the 

concentration of spores was adjusted to approximately 2000 spores/pl with a Coulter counter 

(Coulter Electronics Inc., Hialeah, Florida). A 

Hamilton syringe and repeating dispenser were 

used to deliver 1 ill droplets to embryo hypocotyls. 

Before they were germinated P. taeda seeds were 

nicked at the micropylar end and incubated 4 to 

5 days in 1% hydrogen peroxide at 28 to 30°C. 

Seedcoats were removed and the seeds were surface 

sterilized in 15% Chlorox for 5 minutes, then 

rinsed twice in distilled water. Embryos were 

aseptically excised from gametophytic tissues and 

grown on a Greshoff and Doy x 5 medium (Mott and 

others, 1981) for 1 week before inoculation. 

After inoculation, seedlings were maintained at 

23°C in the dark for 3 days, then transferred to 

a mixed incandescent/florescent light environment. 

Seedlings were evaluated from 3 to 8 weeks after 

inoculation, along with uninoculated control 

seedlings of equivalent age from the same families. 

Antigen Preparation 

Northern red oak (Quercus rubra) -- leaves bearing 

telia columns of C. quercuum f. sp. fusiforme 

were obtained from the USDA Forest Service Resistance Screening Center in Asheville, NC. Telial 

columns were removed and individually rolled on 

1.5% water agar to remove urediospores. Columns 

were gathered into groups of five and suspended 

over a modified Greshoff and Doy medium plus 1 

gm/l yeast extract and 1 gm/l peptone (Amerson 

and others, 1978). Basidiospores were discharged 

from the telia onto the medium to produce axenic 

colonies. Kycelium used for antigen preparation 

was subcultured from these plates and grown in 

darkness at 24°C in a liquid Greshoff and Doy 

medium with 1% bovine serum albumin. Eight-weekold Cqf mycelial cultures were collected in a 

BuchG funnel (Whatman #I filter paper), washed 

several times with phosphate buffered saline 

(PBS) (pH=7.4) and ground in a glass mortar with 

motorized pestle. 

The homogenate was centrifuged twice (10,000 g, 

10 minutes), and the pellets were combined. The 

pellets were resuspended in a volume of PBS equal 

to three tines the pellet weight and stored at 

-4°C. For immunization of the rabbits, the fungal 

homogenate was diluted to 0.003 gm/ml and a 0.03 

nl aliquot was emulsified in 2 ml PBS and 1.7 ml 

Ereund's incomplete adjuvant. Two New Zealand 

white rabbits were injected weekly for 4 months 

with 2 ml of emulsified suspended given intramuscularly and subcutaneously. After 1 month of 

immunization, the rabbits were bled weekly from 

the marginal ear vein. Reactivity of the blood 

serum was tested by an agar double immunodiffusion 

test (Ouchterlony, 1958) and was seen as a visible 

precipitation band. 

Immunoglobulin Preparation 

The immunoglobulin (Ig) fraction from the antiserum was purified by precipitation with an equal 

volume of 36% saturated sodium sulfate. The Ig 

precipitate was collected by centrifugation at 

650 g for 15 minutes and the pellet washed twice 

with 18% sodium sulfate. The Ig was resuspended 

in 2 ml of half-strength PBS and dialyzed 

exhaustively against half-strength PBS at 4OC. 

The Ig fraction was adjusted with 0.02% NaN 

inhibit microbial activity. The purified 3 to 

Ig fraction was stored at 4°C. 

Indirect ELISA (ID) 

Test samples were ground in a tissue homogenizer 

with virus buffer (PBS + 0.05% Tween-20 + 2.0% 

polyvinyl-pyrolidone [Sigma]). Samples were 

serially diluted in coating buffer (Na GO 0.15M; 2 3 NaHC03 0.035N [pH=9.8]) and 200 pl were added to 

the Immulon I1 ELISA plates (Dynatech Laboratories 

Inc., Alexandria, VA 22314) for 3 hours at 36°C 

in triplicate wells. Plates were washed by 

flooding wells with PBS + 0.05% Tween-20 + 0.5% 

egg albumin. Additional washings between incubation steps were done with PBS + 0.05% Tween-20. 

After incubation and washing, 200 p1 of purified 

Ig were added per well, and the plate was incubated 

overnight at 4°C. After three washes, 200 pl of 

goat anti-rabbit alkaline phosphatase conjugated 

Ig (1:1000) were added to each well. Plates were 

incubated for 2 hours at 37'C and washed three 

times. Ninety minutes after the addition of 

substrate (p-nitrophenol phosphate [l.Omg/ml in 
10% diethanolamine (pH=9.8]), absorbance values 

(405 nm) were determined by a Titertek Xultiskan 

photometer (Flow Laboratories, Mctean VA 22104). 

The sensitivity of the ID ELISA was tested using 

dilutions from 5000 at 20 pg/ml of a 1:10 Gqf 

mycelial homogenate. These fungal concentrations 

were tested at l:700, 1:800, and 1:1200 dilutions 

of antibody followed by 1:1000 dilution of goat 

anti-rabbit cunjugate. To test for binding 

interference between fungal mycelium and plant 

extracts on the ELISA plate, 100 mg/nl of healthy 

plant homogenate were mixed with each dilution of 

- Cqf mycelium so that equal healthy plant concentrations were maintained at each dilution. 

Indirect Preabsorption ELISA (IPA) 

Wells of an ELISA plate were coated with 200 ~1 

of a 1.0 mg/ml Cqf mycelial homogenate and incubated for 3 hours at 36*C. Plates were washed 

with PBS + 0.05% Tween-20 + 0.05% egg albumin. 

In a separate test tube, plant and or fungal 

dilutions were mixed with an equal volume of Ig 

at 1:800 and incubated for 4 hours at 4'C. 

Following incubation, samples were centrifuged 

at 7000 g for 10 min. The supernatent containing 

unprecipitatea antibody was removed from each 

sample, and laced in the previously coated wells 

of the ELISA plate followed by incubation overnight at 4°C. After incubation, plates were 

washed (PBS-Tween) and goat anti-rabbit alkaline 

phosphatase conjugate at 1:l000 dilution was 

added at 20>l/well. Development of the plates 

was as described in the ID ELISA. 

RESULTS AND DISCUSSION 

To determine the sensitivity of detection of 

-7 

Cqf antisera to Gqf mycelial homogenates, three 

homogenate dilutions at 10, 0.1 and 0.001 mg/ml 

were tested over a range of antibody dilutions 

(data not shown). A 1:600 to 1:800 dilution of 

antibody detected a 0.1 mg/ml dilution of Cqf. 

had a small standard deviation and maintained 

large difference in absorbance from healthy plant 

controls. At a 0.1 mg/ml dilution of Cqf a 1:600 

antibody dilution had an average absorbance of 

0.153 r 0.034 and a 1~800 antibody dilution had 

0.135 t 0.011 absorbance. Healthy plant homogenates (100 mg/ml) tested at antibody concentrations of 1:400 and 1:1000 had an absorbance of 

0.045 t 0.024 and 0.035 "0.09, respectively. 

An ID ELISA standard curve for the detection of 

- Cqf mycelial homogenates (Figure 3) indicated 

that each of three dilutions of the antibody 

(1:700, 1:800, and 1:1200) could detect Cqf 

homogenate down to 20 pg/ml dilution at which 

point healthy plant absorbance began to interfere. 

In the ID ELISA, absorbance from healthy plant 

homogenate remained uniform at all concentrations 

tested with a l:700 antibody dilution, indicating 

little specificity for the antibody. Part of 

this constant absorbance may be due to nonspecific 

binding of secondary antibody (goat anti-rabbit) 

a 

CONCENTRATION ()~q t mlf 

PI!XRE 3, Indireer ELXSA for C& ac 3 aucibo$p coacencrations. 

(Van Regenmortel 1982). Conjugate alone had a 

mean absorbance of 0.021. 

In the ID ELISA, when Cqf_ and plant homogenates 

were mixed, detection of Cqf was severely inhibited. Healthy plant homoGates may have nonspecifically adhered to the polystyrene plate, 

thereby interferring with Cqf binding. This 

interference limited detection levels in 

infected plant samples and led to the adoption 

of an indirect preabsorption ELISA (IPA). This 

procedure circumvents nonspecific binding by 

healthy plant homogenates by allowing dilutions 

of plant, fungus and antibodies to preincubate 

together in a tube before being put on the ELISA 

plate (Figure 2). The IPA ELISAs detection of 

Cqf mycelial homogenates alone or mixed with 

healthy plant homogenates was possible at less - 

than 10 pg/nl fungal fresh weight. Detection of 

Cqf mycelial homogenate alone and mixed with 

healthy plant were similar, thus indicating little - 

or no healthy plant interference. 

- 

Detection of Cqf in Pinus Taeda 

Cqf mycelium was detected in all inoculated 

-- 

P.=eda seedlings tested 3 to 8 weeks after 

inoculation with basidiospores (Figure 4). 

Healthy plant controls were significantly different 

(P=0*05) from Cqf inoculated plants at every 

week tested. Levels of the fungus appeared to 

decrease over time as more plant material was 

incorporated into the assay each week (Figure 4). 

This decrease may have been due to a resistance 

mechanism in families such as 7-56, which is 

rated as field resistant (P.L. = 65). More likely, 

the growth of the seedling relative to the infection 

site was not taken into consideration in these 

preliminary assays. It is important to note 

however, that the antibody to axenic hyphae and 

this same antibody was then able to detect Cqf 

infection from basidiospore infections. The 

growth differential and an earlier sampling time 

after inoculation will be taken into account in 

future assays before quantitative evaluations can 

be nade. 
1 3 weeks 

A S reeks 

0090 @ ? weeks 

Oo 

I f I .I 

10 100 Ern ~opoo 

DILUTION OF 1:IO P. toeda HOMOGENATE (yg/ml) 

FIGURE 4. Indirect Preabsorption ELISA of P. eaeda seedlings 

3, 5 and 7 weeks after inoculation wtth C& basidiospares and cantroi seedlings of equivalent age. 

In conclusion, a sensitive ELISA immunoassay for 

the detection of Cq5 mycelium in inoculated P, 

taeda seedlings has been developed. ELISA is a 

sensitive tool capable of examining hostpathogen relationships and can be used in combination wirh tissue culture to study different 

environmental and nutritional settings. Once 

the growth dynamics of the fungus and the host 

are better understood, we can begin to use the 

ELISA for the quantitative evaluation of Cqf 

infection in genotypically different P. taeda 

l ines . 

LITERATURE CITED 

Agrios, G.N. Plant disease. New York: Academic 

Press; 1978 390-394. 

Amerson, H.V.; Frampton, L.J., Jr.; Mott, R.L. 

-- In vitro methods for the study of fusiform 

rust in association with loblolly pine. In: 

Barrows-Broaddus. Jane; Powers, H., comps and 

eds. Proceedings rusts of hard pines working 

party conference. S2.06-10, IUFRO; Athens, GA: 

University of Georgia; 1985: 103-124. 

Amerson, H.V.; Hott, R.L. Technique for axenic 

production and application of Cronartium 

fusiforme basidiospores, Phytopathology 

68:673-575; 1978. 

Anderson, R.L.; Mistretta, P.A. Ffanagement 

strategies for reducing losses caused by 

fusiform rust, annosus root rot, and littleleaf 

disease. Integrated Pest Management Handbook. 

Agric. Handb. 597; Washington, DC: U.S. 

Department of Agriculture, Forest Service; 

1982. 

Casper, 4.; Mendsen, K. Quantitative serologicai 

estimation of a hyperparasite: detection of 

Verticillium lecanii in yellow rust infected 

wheat leaves by ELISA. Phytopathology 94. 

89-91; 1979. 

Cunningham, A.T. Understanding innunology. 

New York: Academic Press; 1978- 1-28. 

Czabator, F.J. Fusiforrn rust of southern pine-- 

a critical review. New Orleans, LA: U.S. 

Department of Agriculture, Forest Service, 

Southern Forest Experiment Station; 1971. 25 pp. 

Dinus, R.J.; Schmidt, R.A. Management of fusiform 

rust in southern pines. Symposium Proceedings: 

Biology of fusiform rust. University of 

Florida; Gainesville: 1976: 18-24. 

Frampton, L.J.; Amerson, H.V.; Weir, R.J. 

Potential of in vitro screening of loblolly 

pine for fusiform rust resistance. Proceedings, 

17th Southern Forest Tree Improvement Conference. 

1983; June 6-9. Athens, GA: Southern Forest 

Tree Improvement Committee sponsored publication 

39; 1983: 325-331. 

Gooding, G.V., Jr.; Powers, H.R., Jr. Serological 

comparison of Cronartium fusiforme, C. quercuum 

and C. ribicola by immunodiffusion tests. 

Phytopathology 55:670-674; 1965. 

Gray, D.J.; Amerson, H.V. In vitro resistance 

of Pinus taeda embryos to the fusiform rust 

fungus Cronartium quercuum f. sp. fusiforme. 

Ultrastructure and histology. Phytopathology 

73:1492-1499; 1983. 

Jewell, F.F. Inoculation of slash pine seedlings 

with Cronartium fusiforme. Phytopathology 

50:48-51; 1960. 

Johnson, M.C.; Pirone, T.P.; Siegal, M.R.; 

Varnay, D.R. Detection of Epichloe typhina in 

tall fescue by means of enzyme linked immunosorbent assay. Phytopathology 72:647-750;1982. 

Koenig, R.; Paul, B.L. Variants of ELISA in 

plant virus diagnosis. Journal of Virological 

Methods 5:113-125; 1982. 

Martin, F.; Botton, B.; Yxatef, Y. Enzymelinked immunosorbent assay of NADP+-glutamate 

dehydrogenase. Plant Physiology 72:398-401; 

1983. 

Miller, T.; Cowling, E.B.; Powers, B.R., Jr.; 

Blalock, T.E. Types of resistance and compatibility in slash pine seedlings infected by 

Cronartium fusiforme. Phytopathology 66: 

1229-1235; 1376. 

Mott, R.L-; Amerson, H.V. A tissue culture process 

for the clonal production of loblolly pine 

plantlets. Raleigh, NC: Eorth Carolina Agricultural Research Service. Tech. Bull. 271. 

1981: 14 pp. 
Ouchteriony, 0. Diffusion-in-gel methods for 

immunological analysis. Progress in Allergy 

5:l-78; 1958. 

Savage, S.D.; Sall, M.A. Radioirrlmunosorbent assay 

for Botrytis cinerea. Phytopathology 71: 

411-415; 19817- 

Schmidt, R.A.; Powers, H.R., Jr.; Snow, G.A. 

Application of genetic disease resistance for 

the control of fusifora rust in intensively 

managed southern pine. Phytopatbology 71: 

993-997; 1981, 

Van Regenmortel, M.Y.V. Serology and immunochemistry of plant viruses. New York; Academic 

Press; 1982; 113-133. 

VolLer, A.; Bidwell, D.; Bartlett, A. Microplate 

ELTSA and its applications: immunoenzymatic 

assay techniques. In Malvano, R., ed. Developments in Clinical Biochemistry. Vol. 1. 1980: 

113-220. Hague and Boston. 

Yolken, R.H. ELLSA. Enzyme-linked immunosorbent 

assay. Hospital Practice. 1978, December: 

121-127. 
THE BIOLOGY OF LEUCOLOPS I S PULVERITLENTA DOGN IN 

(L~EPIDOPTERB , CEOMETRIDAE) 

Joy Woolfson ds ?Joboa2 

Since imnemorable times, even before the Spanish 

colonization of Ecuador, the forest resources of 

the country were exploited witho~lt any kind of 

prntectinnal policies, By the beginning of this 

cent~~ry the highlands palled "'La Sierra" were 

a lmost completely deforested, 

Becarlse of this reason, some fast growing trees 

like Pinus and Eucalyptus were brought to reforest 

the highlands, Br~t with the introduction of these 

exotic species and the forming of monospecies 

woods eco Logical changes happened, bringing with 

them some problems such as the adaptation of native 

species of insects to these trees. 

This is the case of the defoliator Leucolopsis 

gulverulenta, a white moth known only from Colombia 

and Ecuador that has changed her food preferences 

from native shrubs like Lupinus sp, and Wypericum 

Iaricifolium to the now more abundant Pinus radiata 

in some areas of the highlands. Cyclically it can 

become a pest that delays the natural growing rate 

of the groves and sometimes kills the trees. 

This work is about the biology of xhe White Moth. 

It is supported by an agreement between the United 

States Agency for International Development, the 

Ministry of Agriculture of Ecuador and the 

Pnntificia llniversidad Catolica del Ecuador. It 

is divided in two parts. In the first part the 

life cycle of the moth is studied under laboratory conditions. In the second part, a census 

was made to determine the annual population variations of the moth in nature. 

mTERIALS AND NETHODS 

The laboratory colony was established from eggs, 

larvae, pupae and adults collected during perl;odical visits to the Parque Nacional Cotopaxi, a 

paramo park located from 3500 to 5897m over sea 

level, one hour south from Quito; that was reforested with some species of the genus Pinus, 

mainly with I?. radiata. 

'presented at the Symposium on Current Topics 

in Forest Research: Emphasis on Contributions by 

Women Scientists, November 4-6, 1986, Gainesville, 

Florida. Co-sponsored by the USDA Forest Service, 

Southeastern Station, and the University of Florida. 

2~ntomologia Forestal, Depto. de Biologia, 

Pontificia Universidad Catolica Del, Ecuador - Aptdo, 2184 Quito - Ecuador. 

The eggs were kept in plastic boxes with filter 

paper and moistare, until hatching- After that the 

larvae were separated. The larvae were reared at 

room temperature (10 - 20 degrees centigrade), 

each one in a plastic transparent round Sox 4c~ x 

i.5cm with filter paper at the bottom moistened 

with a 0.04% formaldehyde solution and fresh, 

young pine needles that were changed every other 

day. At the same time, the boxes were monitored 

for the presence of molts. The pupae were sexed 

and placed in soap-boxes 9 x 6 x 2.5 cm with 

filter paper and the same moistening solution. 

All the boxes were sterilized with a 2X formaldehyde solution before using. 

For reproduction, a newly emerged male and 

female were placed together in a transparent plastic bag, with filter paper, moistening solution 

and a small cotton ball soaked in sugar solution. 

The bags were checked daily for eggs. 

To make the adult population census, a square 

meter was marked on the wall of a house at the 

Parque Nacional Gotopaxi. Each month since 

March 1986, on the night of a new moon, a light 

trap was used to attract the moths that were collected and counted each hour for three hours. 

DESCRIPTION OF THE INSECT 

The adult is a white brilliant moth, with little 

silver spots on the anterior wings; wingspread 

measures 20 to 40 mm, being the males generally 1 

bigger than the females, the head is orange; the 

female has filiform antennae and the male plumose. 

The eggs are light green, oval and their size 

is approximately 0.75 x 0.5mm. When they are close 

to hatching the color changes to purple. 

The first instar larva is greenish with two 

yellowish dorsal lines and a black cephalic 

capsule. From the second instar the larva is 

greenish-yellowish with a black dorsal stripe 

and two black lines on each side; the cephalic 

capsule, the feet and the prolegs are orange, 

The pupa is greenish with black spots on the 

abdomen and black lines on the wing area. 

The duration of each stage is indicated in 

Table 1 together with the mode which serves to 

make a representative life cycle of the moth. 

The sizes of the cephalic capsules can belp to 

determine the instars of the larvae in the field. 1 
TABLE 1 

STAGE R4H G E MODE ' SIZE SIZE OF 

CEPHALIC CAP. 

days days m nm 

Egg 

1st. instar 

2nd. instar 

3rd. instar 

4th. instar 

5th. instar 

6th. instar 

Prepupa ' 

Prtpa 

hdu 1 t 

Mode.- Is the most repeated number inside the range. 11 Prepupa.- This stage is already counted in the sixth instar. 

The cycle begins with the oviposition, in 

nature the eggs are Laid in two or three columns 

on the pine needles, in the laboratory the eggs 

are laid uneven in the bags where the females 

have been placed. 

After hatching, the larvae leave the corion 

almost complete. These first instar caterpillars 

are very active. They go towards the light and 

hang from silk threads. Maybe this is their dispersal mode. 

As the percentage of survival indicates in 

Table 1, the first and second instar larvae are 

the most delicate. They can be affected by viruses, f ungi or bacterial diseases and changes in 

the environmental humidity and food deficiency, 

Of course, these factors also affect the older 

larvae, but as they grow they get stronger. 

In their sixth instar, the larvae enters the 

prepupal stage that takes the last two days, The 

larvae stop eating, their color turns greener 

and they make a very light silk web. 

The adults have nocturnal habits, the mating and 

laying of eggs occurs during the night. A female 

can lay 20 to 200 eggs in a time of 1 to 6 days. 

The sex ratio male to female is 1.1 to 0.9. 

Figure I represents the life cycle of the moth 

which lasts approximately three and a half months 

under laboratory conditions; the larval period 

which causes-the damage to the trees takes 56% 

of the cycle, 

Analyzing Figure 2, the time between the peaks, 

May through October, represents the field life 

cycle which is slightly longer than the one in the 

laboratory. This can be explained because the 

laboratory conditions of humidity are relatively 

stable, but in the field, the insect has to go 

through the dry season estivating. 

The population of this moth is now controlled 

naturally by the pathogens named before and by 

two microhymenoptera parasites, one, a Scelionidae, 

of the eggs and the other, Casinaria cavigena, an 

ichneumonid of the larvae. 
FIGURE I: The life cycle 

pupa 

adult 

egg 

larva 

FIGURE 2 : Relation cycle- seasons (dry or rainy) 

1 

Months 
Soil Solar Heating for Pest Control at Colorado 

and Nebraska Forest Tree ~urseries l 

Diane M, ~ildebrand~ 

Abstract.--Solar heating by covering soil with 

thin clear polyethylene sheeting for several 

weeks during summer significantly reduced populations of weeds and damping-off fungi at the 

Colorado State Forest Service Nursery and the 

USDA Forest Service Bessey Nursery (Nebraska). 

Daily high temperatures achieved under the 

polyethylene averaged 8'5°C higher than in 

uncovered control plots. The maximum temperature 

recorded in solar-heated plots exceeded 46°C at 

8 crn depth, Seasonal fluctuations in mineral 

ions in the soil solution were greater than 

differences due to solar heating. Oats planted 

immediately after solar heating exhibited an 

increased growth response in the solar-heated 

plots. However, lodgepole pine sown the following 

spring did not show a similar response. 

Keywords: whim spp., Fusarim spp., soil 

chemistry, weeds, Pznus contorts, solar 

pasteurization. 

Forest tree nurseries produce a valuable crop-- 

tree seedlings for reforestation, afforestation, 

and shelterbelts, as well as for ornamental 

plantings. In 1985, state and Federal forest 

nurseries produced about 850 million seedlings 

for forest and shelterbelt plantings on 140,000 

ha (345,000 acres) across the United States 

(Forest Service, 1386). In 1985 in the Rocky 

Mountain Region of the USDA Forest Service 

(Colorado, Wyoming, South Dakota, Me braska, and 

Kansas), trees were planted on 2,600 ha (6,400 

acres) on Federal lands alone (Forest Service, 

1986), Tree seedlings are a high value crop; 

conifer stock at the U. S, Forest Service Nursery 

in Nebraska is worth over $90,000 per 0.4 ha 

(1 acre). 

Soil-borne nursery pests including weeds and 

plant pathogens affect the production of tree 

seedlings, The primary impact of weeds is 

reduction in crop yield due to competition for 

light, water, space, and nutrients. Because 

conifer seedlings grow slower than most weed 

species, nursery weeds can greatly reduce the 

yield and quality of the crop (Owston and 

Abrahamson, 1984). Weed control in bare root 

nurseries usually includes fumigation before 

sowing, applications of herbicides, and weeding 

by hand. Not all of the weeds are controlled in 

one herbicide application, and repeated applications may be necessary. Often more than one 

kind of herbicide must be used, because no single 

herbicide is both safe for growing tree seedlings 

as well as effective against all weed species. 

Nearly all herbicides used sometimes cause 

phytotoxicity in the tree crop (Owston and 

Ab rahams on, 1984). Weeding by hand is usually 

necessary and is very expensive. 

Presented at the Symposium on Current Topics 

in Forest Research, Emphasis on Contributions 

by Women Scientists, A National Symposium, 

November 4-6, 1986, Gainesville, FL 

Plant Pathologist, Rocky Mountain Region, 

USDA, Forest Service, Lakewood, GO 80225 

Among the most widespread and destructive 

diseases of nursery tree seedlings is damping-off, 

which kills the seedlings either before (preemergence) or immediately after (pos t-emergence) 

they break through the soil (Sutherland and Van 

Eerden, 1980). Several fungi can cause this 

disease, but the most common in the Rocky 

Mountain Region are species of Fusarium and 

L%thium. Only very young seedlings are affected, 

and these soil-borne fungi directly invade the 

radicle and/or the hypocotyl at the ground line. 

After the seedling develops woody tissue, in four 

t o s i x weeks, they are no longer susceptible to 

damping-of f. Damping-of f pathogens survive 

saprophytically or as various types of thickwalled spores in the soil between crops 

(Sutherland and Van Eerden, 1980). 

Fumigation 

Soil fumigation is widely used today in bareroot nurseries because soil-borne pathogens and 

weeds are controlled in a single application 

(Cooley , 1985). The most commonly used fumigant, 

67% methyl bromide with 33% c hloropicrin 

(trichloronitromethane), is injected into the 

soil several inches below the surface, and the 

soil is immediately covered with polyethylene 

sheeting. The polyethylene is removed after a 

few days, and the soil is allowed to aerate 

before planting. Fumigation by commercial 

contractors costs approximately $1,100 per 0.4 

ha, but is cost-effective considering the 

reduction in costs required for hand-weeding 

alone (Boyd, 1971; bndis et al. , 1976). 

A1 though widely used, chemical fumigation has 

several drawbacks. Fumigation is not always 

effective due to problems in even distribution of 

the fumigant. Fumigation inefficiencies are often 

not detected until the tree seedlings emerge and 

damping-off or weeds become evident. In addition 

to soil-borne pathogens and weeds, many kinds of 

desirable organisms are also destroyed by chemical 

fumigation. Populations of decomposers, detritivores, and mycorrhizal fungi are decimated. 

Endomycorrhizal fungi are more sensitive than 
damping-off fungi, and ecto~corrhizal fungi are 

also destroyed (Munnecke and Van hndy, 1979). 

In addition, fumigation chemicals are hazardous 

to apply and require special handling. Fumigant 

vapors may damage nearby vegetation. Recent 

restrictions in the use of fumigants related to 

methyl bromide indicate a need for alternative 

chemical and cultural practices. Atternative 

chemical fumigants include forms of biodegradable 

methyl isothiocyanate, e.g. Basamid granular. 

Solar Heating 

Solar heating of soil is a cultural practice 

that is less expensive and less hazardous than 

fumigation, and destroys fewer beneficial 

organisms. Solar heating (solar pasteurization, 

soil solarization) consists of covering moist soil 

with clear polyethylene sheeting for several weeks 

during the hottest months to reduce population 

levels of soil-borne pathogens and weeds (Katan 

et al., 1976). 

Solar heating has been effective against a 

variety of weeds and soil-borne pathogens, 

especially for agricultural crops in warn climates 

such as Israel and California (Grinstein et al., 

1979; Jacobsohn et al. , 1980; Ashworth and Gaona, 

1982). Studies also showed that disease reduction 

was still evident the second growing season after 

solar heating l ata an et al. , 1983; Pullman et al, , 1981b). 

In some climates, solar radiation can increase 

soil temperatures to over 40°C at a depth of 30 

cm under polyethylene sheeting (Pullman et al., 

1981b), chiefly by preventing evaporation and 

partly by the greenhouse effect (Mahrer, 1979). 

Continuous or repeated sub-lethal temperatures 

under moist conditions over long periods either 

kill pathogenic fungi directly or weaken them so 

they cannot compete effectively with saprophytes. 

In laboratory tests, 90% of the propagules of 

VerticiZlim daizZiae Kleb. died after two hours 

at 45"~ or after seven days at 38.5"C in natural 

field soil. In pure culture at 45OC, seven hours 

were required for 90% mortality (Pullman et al., 

1981a). Plant pathogens are apparently more 

sensitive to elevated temperatures than are 

saprophytes. Mycorrhizal fungi such as GZomus 

f cZs~ieL4Zatus (~h axter) Ge rd. 6 Tr appe can survive 

solar heating and colonize crop roots (Pullman et 

al., 1981b). 

Besides the direct effects of elevated temperature during solar heating, toxic effects of 

released volatiles from soil organic matter may 

contribute to pest control. Zakaria et ale (1980) 

found that volatile degradation products of 

oilseed meal amendments reduced populations of 

Fusarium spp. in closed containers. 

Horowitz et al. (1983) found that foliar 

scorching and decreased emergence were the main 

effects of solar heating on weeds. In their study 

the lowest damaging temperature for weed seeds 

was 45"C, and moisture was found to sensitize 

seeds and other weed propagules to damage by heat. 

Solar heating nay affect soil chemistry. For 

example, a few studies have reported increases in 

nitrate and ammonium nitrogen, potassium, calcium 

magnesium, chloride, and phosphate in the soil 

solution due to solar heating (St apleton et al, , 1983; Chen and Katan, 1980). In addition to 

disease reduction, this increase in soluble 

mineral nutrients may contribute to the increased 

growth response observed in crops grown in solarheated soil (Stapleton et al., 1983). 

Solar heating of soil for conifer nurseries has 

been evaluated recently in a few areas of the 

United States, Kesults at the Iowa State Xursery 

at hes indicated reduced populations of weeds 

from solar heating but no significant decreases 

in populations of Pusarim spp. (Croghan et ale , 1984). In trials at the Bend Sursery in eastern 

Oregon, Cooley (1983) found that populations of 

r'usarim spp. were significantly reduced by solar 

heating, but tree seedling survival after ten 

weeks was similar in control and solar-heated 

plots. Results at the J. Herbert Stone Nursery, 

Medford, Oregon (Cooley , 1985) indicated significant reductions in populations of F'usarim spp. 

due to solar heating, but again seedling survival 

was not improved. 

Nursery managers in Colorado and We braska were 

interested in alternatives to methyl bromide for 

controlling weeds and damping-of f fungi. This 

study was undertaken to evaluate solar heating 

for reductions in pest populations and to measure 

changes in thc soil solution and any growrh 

response in a conifer crop, This study showed 

some significant reductions of 2~&hiion spp, , Pusariwn spp., and weeds by solar heating in 

Colorado and Nebraska, but no beneficial effects 

in lodgepole pine sown the following spring. 

MATERIALS AAID METHODS 

Study Area Locations 

Solar heating trials were conducted at two 

nurseries in the Rocky Mountain Region, The 

Colorado St ate Forest Se rvice (CSFS) Nursery is 

located on the western edge of Fort Collins, 

Larimer County, Colorado, at 1560 m (5120 f t) 

elevation. The soil in the study area was mainly 

Kim Loam with areas of Al tvan Sandy Clay Loam 

(Moreland, 1980). Tree seedling production began 

at the nursery in the middle 1960's. Study plots 

were located in a nursery block in which an entire 

spruce planting had been recently plowed under due 

to excessive losses to damping-off. The nursery 

block was 91 m by 41 m (300 ft by 200 ft), sloped 

gently (1-3%) to the southeast, and had never 

been fumigated, 

The USDA Forest Service Bessey Tree Xursery is 

located on the north edge of the Nebraska National 

Forest, Bessey Division, 3 km west of HaLsey, 

Thomas County, Kebraska, at 840 m elevation. The 

soil in the study area was &adin loamy sand of 

the Dunday-Loup association in the Middle Loup 

River Valley (Sherfey et al. , 1965). Daqing-of f 

(Hunt, 1965) and nematode damage (Peterson, 1962) 

are recurring problem at Bessey Nursery, and 
methyl bromide funiyation before sowin? is 

standard procedure. 

Soil Treatments 

At each nursery, six treatment plots 

(3.7 rn x 61 m at CSFS, and 3.2 m x 15.2 m at 

Bessey) were arranged at least 1.2 m apart in a 

randomized block design parallel with nursery 

beds during the summer (1982 at CSFS and 1983 at 

Bessey). After irrigation to field capacity, 

three plots were covered with thin (0.05 rnm at 

CSFS, and 0.038 mm at Bessey) clear polyethylene 

for eight weeks for solar heating, and three 

plots were left uncovered as controls. 

Before polyethylene placement, six Ryan model J 

thermographs (Ryan Instruments, Inc. , Ki rkland, 

WA 98033) were buried to record range and 

duration of temperatures. At CSFS, one thermograph was buried at 8 cm and one at 15 ern depth 

along the center of each of two solar plots and 

one control plot at a random distance fron the 

ends. At Bessey, three thermographs were buried 

1.5 to 2 m apart near the center of one control 

and one solar plot, one each at 8 cm, 15 cm, and 

30 em depths. 

Soil Assay 

Soil samples for laboratory assay of populations 

of species of Pythim-, fisarim, and viable weeds 

were taken in June before polyethylene placement, 

in late August after polyethylene was removed, 

and the following spring before sowing, 

For assay of damping-off fungi four soil 

samples--composites of several cores taken to a 

depth of 15 cm with a soil probe within a 30 cm 

radius-were collected at regular intervals along 

the center of each of the six plots, the first 

sample location chosen at random. Assay for 

species of Pgthi~n and r'usarim were similar to 

procedures used by Johnson and Zak (1 977), except 

three instead of five plates of selective media 

were used per sample. 

For comparison purposes, population levels of 

Pythim spp. of less than 15 propagules per gram 

of soil (PPG) were considered low, 15 to 25 PPG 

moderate, and over 25 PPG high, Population levels 

of Fusaritan of less than 1000 PPG were considered 

low, 1000 to 1500 PPG moderate, and over 1500 PPG 

high* These Levels correspond to levels of damage 

observed in nursery soils 3. 

Soil for weed assay was collected fron the top 

2.5 cm of soil from within a 929 cm2 (I square 

foot) frame for each sample, with four samples 

taken per treatment plot. Each soil sample was 

poured into an aluminum foil pan, watered as 

needed and kept in a Scherer Environmental Chamber 

with 12 hours light at 25°C and 12 hours dark at 

Russell, Kenelrn ici, 1986. Data presented at 

the Nursery Pathologists Workshop, Feb. 19-20, 

Mestwater Inn, Olympia, MA. (Forest Pathologist, 

Washington St ate Dept. Natural Resources, Olympia 

98504). 

18°C. After two weeks weea seedlings were 

counted. This germination test estimated the 

number of weeds expected to develop if a crop 

were planted. 

The significance of treatment effects on 

populations of species of Py tii;a?~, iP'zlsari~i3 and 

weeds was determined by two-way analysis of 

variance where homogeneity of variances could be 

achieved by data transformation, Citnerwise, the 

more conservative "test for equality of means 

whose variances are assumed to be unequal" (Sokal 

and Rohlf , 1981) was used. Post-treatment values 

were compared with the pretreatment values and 

then with the values for the spring after 

treatment. 

Soil samples were collected from Bessey Nursery 

for analyses of minerals in the soil solution and 

other properties. These samples were composites 

of nine probe cores taken 6 m from the ends of 

one solar and one control plot. The two sample 

locations were less than 4.6 m apart, on either 

side of an irrigation line. Soil was sampled 

before polyethylene placement in June 198 3, after 

polyethylene removal in August 1983, and the 

f olLowing spring 1984. These samples were 

analyzed by the Colorado State University (CSU) 

Soils Testing Laboratory for texture, bulk 

densicy, organic matter, and for the following 

minerals from soil paste (1: 1 soil and water for 

sandy soil) : pH, calcium, magnesium, potassium, 

sodium, nitrate, ammonium, and chloride. 

Tree Seedling Survival 

A crop of lodgepole pine (Pinus eontorta 

Dougl.) was sown in Play 1984 at Bessey to 

evaluate solar heating treatment effects on 

seedling survival. Five subplots (30 cm along 

the bed x 76 cm across the bed, encompassing 4 

rows) were monitored in each of the six treatment 

plots (3 check, 3 solar). The number of surviving 

seedlings were counted beginning two weeks after 

sowing on May 25, 1984, and then approximately 

every two weeks through July 17. A final count 

was made on October 1, 1984. 

RESULTS 

Soil Temperature 

At the CSFS Ikrsery , highest temperatures 

averaged 9.5"C higher in the solar plots than in 

the control plot. Average temperatures recorded 

by the thermographs at 8 ern were usually much 

higher than those at 15 cm, especially in solar 

plots (fig. 1). Due to equipment malfunction, 

the 8 cm thermograph for the control plot was not 

buried until July 12, and the temperature record 

for one of the 15 cm thermographs buried in a 

solar plot was lost after July 24. Because the 

recording range of the thermographs used at CSFS 

was 10-40°C, temperatures above 4 1°C were of fscale. The average high temperatures are 

under-estimated for the solar plots, because 

the highest value used in the computation 

was 41°C. At CSFS the temperature exceeded 

41°C on 45 days at 8 cm, and four days 
8 cm Solar 

41+"C (10h) 

(two thermograph s ) 

15 cm Solar 

41+"C (Sh) 

(two therrnographs 

8 cm Control 

39°C (4h) 

15 cm Control 

34°C (4h) 

Last Day of Week, 1982 

Figure 1. Weekly averages of daily high temperatures recorded by thermographs buried at 8 and 15 cm in two 

solar and one control plot at the Colorado St ate Forest Service Nursery, 1982. Highest temperature achieve! 

and the duration in hours (h) that the temperature remained within 1°C of the high is given for each 

t hermograph. 

at 15 cm in the solar-heated plots, with an Pythium Populations 

average duration of six hours. Temperatures in 

control plots steadily decreased due to shading At the CSFS Nursery solar heating resulted in 

by weeds. significant (P<0.05) decreases in population 

levels of Qthiwn spp, (Table 1). Population 

At Bessey Nursery highest temperatures averaged levels of Pythiwn spp. decreased over the winter 

8°C higher in solar than in control plots. in a11 plots, Population levels in control plots 

Average high temperatures recorded at 30 cm were decreased from high to moderate, while levels in 

much lower than near the surface (8 cm), but solar-heated plots decreased from moderate to lowI 

temperatures remained within 1°C of the daily 

highs much longer at greater depth (fig. 2). The At Be ssey Nursery the population levels of 

temperature achieved at 8 cm in the solar plot Pythim spp. were initially different between 

exceeded 46°C (the limit of the recording control and solar plots before polyethylene 

capability of the thermographs used at Bessey) placement in June 1983 (Table 1). By August 1983 

several times. At these times, the temperature the solar heating treatment significantly reduced 

remained above 45OC for two to six hours, with population levels in solar plots, while those in 

an average of 4.1 hours. While the temperature control plots remained similar to June 1983 

was off-scale (46+OC) on August 2 at 8 cm in the levels. By the following spring, population 

solar-heated plot, the chart tore and the levels of Pythim spp. had returned to or 

subsequent record was lost. Weed growth was kept exceeded pretreatment levels, probably due to 

to a minimum in control plots by periodic light the influence of the winter cover crop. 

cultivation. 

8 cm Solar 

46+"C (6h) 

8 cm Control : 

38°C (3h) 

I 

30 cm Solar 

36°C (9h) 

15 cm Control" 

32°C (5h) 

30 cm Controls 

28'C (13h) 

Last Day of Week, 1983 

Figure 2. Weekly averages of daily high temperatures recorded by thermographs buried at 8, 15, and 30 cm 

in one solar and one control plot at Bessey Nursery, 1983. Highest temperature achieved and the duration 

in hours (h) that the temperature remained within 1°C of the high is given for each thermograph. 
Table 1, Coefficients of variation, means, and their significance for population levels of %$him spp. 

(propawles per gram of oven-dried soil) in control and solar-heated plots before and after treatment, and 

the following spring at the Colorado State Forest Service Kursery (A) and at Bessey Nursery (B). 

Coefficient Coefficient 

Sampling Treatment of Variation Meana ~opulation~ of Variation Meana Populationb 

Time (Percent ) Level (Percent ) Level 

A. CSFS B. Bessey 

Before Control 88.0 7 63.8 c High 183.07 42.2 cde High 

Solar 87-52 55.8 c Nigh 11 3.00 7.3 b Low 

Af ter Control 58.83 58.2 c High 

Solar 5 5.78 22,l b Moderate 

Spring Control 54.19 18.7 b Moderate 

Solar 136.78 7.3 a Low 

55.63 30.4 cd High 

124.72 0.3 a Low 

52.33 49.9 de High 

44.69 54.8 e High 

a Means followed by the same letter are not significantly different at P(0.05, as determined separately 

for each nursery by the test for equality of means. 

Based on data by K. W. Russell. 

Fusarium Populations 

At the CSFS Nursery solar heating resulted in 

significant (P(0.05) decreases in population 

levels of Fusarim spp. as determined by two-way 

analysis of variance. Homogeneity of variances 

was achieved by transforming data by Y' = Jm, 

in order to use analysis of variance. The interaction between treatment and time of sampling was 

significant, showing that population changes over 

time in the solar plots differed from population 

changes over time in the control plots. This 

indicates a significant treatment effect (Green, 

1979, p. 62). After solar heating, population 

levels of Fitsariton remained high in control plots, 

but decreased from high to low in solar plots 

(Table 2). Over the winter, population levels 

of Pzrsarim spp. greatly increased in control 

plots, while those in solar plots remained low. 

At Bessey Nursery, population levels of 

Pusarium spp. were initially low in all plots and 

remained low (Table 2). Homogeneity of variances 

eved by transforming data by 

, in order to use analysis of 

variance. Two-way analysis of variance showed 

only that population levels of Fusariwn spp. were 

different between control and solar plots both 

before and after solar heating. The interaction 

between treatment and tine of sampling was not 

significant, indicating no treatment effect. 

Table 2. Means of population levels of Fusarim spp. (propagules per gram of air-dried soil) compared 

for control and solar-heated plots before treatment, after treatment, and the following spring, at the 

Colorado State Forest Service Nursery (A), and at Bessey Nursery (B). 

Coefficient Coefficient 

Sampling of Variation Populationa of Variation Populationa 

Time Treatment (Percent) Mean Level ( Percent) Mean Level 

A, CSFS B. Ikssey 

Before Control 45.12 2233 High 39.10 444 Low 

Solar 32.60 3122 High 92.11 2 00 Low 

After Control 68.18 1900 Eligh 

Solar 102,10 822 * Low 

Spring Control 10.38 9745 High 

Solar 45.36 656 Low 

7 8.40 467 LOW 

170.3 1 78 ns Low 

125.10 178 Low 

189.70 100 Low 

a Based on data by K. W. Russell, 

ns = Mo significant interaction, no treatment effect. 

* Significant at P<0.05 indicated by significant interaction between treatment and sampling time 

in two-way analysis of variance. 
Table 3. Coefficients of variation, means, and their significance for weed 

populations (number per 929 cm2) in control and solar-heated plots before 

treatment, after treatment, and the following spring at Colorado State Forest 

Nursery (A), and at Bessey Nursery (B). 

Coefficient Coefficient 

Sampling of Variation of Variation 

Time Treatment (Percent) Mean * (Percent) Mean * 

A. CSFS B. Bessey 

Before Control 80.03 13.3 c 195.03 5.0 b 

Solar 94.97 24.7 c 167.7 1 0.4 b 

After Control 128.00 3.8 b 

Solar 384.4 2 0.3 a 

Spring Control 112.01 211.4 d 

Solar 164.96 30.3 c 

* Means followed by the same letter are not significantly different at P<0.05, 

as determined by test for equality of means. 

Weeds 

At the Colorado State Forest Service Nursery, 

populations of weeds were significantly reduced 

by solar heating (Table 3). By August most of 

the weed seeds in the control plots had germinated 

and the resulting plants matured, and a new crop 

of weed seeds was accumulating on the ground. The 

major weed species growing in the control plots 

and adjacent areas were P~rtu~aea okraeea L., 

PhysaZis heterophyz Za Ne es. , and Amranthus 

retrojtllexus L. Very little weed growth occurred 

under the polyethylene in solar plots although 

some PO oZerac~a was growing slowly in spots. 

some dead weed seedlings were observed when the 

polyethylene was removed. By the spring following 

solar heating, weed populations increased to 

levels greater than pretreatment levels in 

control plots and returned to pretreatment levels 

in solar-heated plots, probably due to intense 

seed production in control plots and adjacent 

areas. Solar heating greatly reduced weed cover 

compared with control plots. Solar-heated plots 

had fewer and smaller weeds than control plots. 

At Bessey Nursery, solar heating significant ly 

reduced weed populations while weeds increased in 

control plots (Table 3). By the spring following 

solar heating, weed populations had returned to 

pretreatment levels, probably due to weed seeds 

blown in from other areas, A variety of weeds 

occurred in the treatment area, including volunteer oats (Auena; fatlca L. var. sativa (L. ) Hausskn. 

anrl chokecherry (Prunus uiryiniam L.) from 

previous crops. The weeds included Trifolitcn 

spp. , PdolZugo vertieiilata L. , Capsella bursapastoris L., Bromu~ teetorm L., and !dedieaga spp. 

Soil Properties 

maqnesiutn (Hg ), sodium (Ha), potassium (K) , chloride (CL), ammonium nitrogen (NH4-N), nitrate 

nitrogen (NO3-i';), and pIf (Table 4). However, 

considering the pretreatment values, slight seasonal increases between June and August were evident for ions of Ca, Mg, Na, K, NH4-nitrogen, and 

NO3-nitrogen. Increases due to solar heating 

over and above summer increases were shown for Ca 

and NH4-nitrogen. Large increases over the 

winter, however, were measured in May for Ca, Hg, 

and EN4 nitrogen in the control sample. These 

winter fluctuations were greater than any increases due to solar heating the previous summer, 

Tree Seedling Survival 

In all plots and treatments, most of the 

lodgepole pine mortality at Bessey occurred at 

the beginning of the arming season. Seedlings 

continued to die at a slow rate through October 

1984. By the end of the growing season, control 

plots yielded 14.3 seedlings/929 cm2 (ft2) and 

solar heated plots 12.4 seedlingsl929 cm2. Due to 

the high variability within treatments, analysis 

of variance indicated no significant effects on 

seedling survival between the treatments. Seedlings in solar-heated plots were not noticably 

larger than seedlings in control plots. By 

October 1, 1984, losses in solar-heated plots 

were 31% and in check plots 27% of the number of 

live seedlings on Hay 25, Although lodgepole 

pine sown in the study area the spring following 

solar heating showed no beneficial effects, the 

oat cover crop was darker green and more lush in 

the solar heated plots compared with that in the 

surrounding control area in November 1 Yd3. 

DISCUSSION 

Soil from the study area at Bessey Nursery was The highest temperature recorded under the 

loamy sand with 1% organic matter, bulk density polyethylene was over 46"~ at a depth of 8 cm. 

of 1-6 g/cm3, and pH about 5.5. If one looked Since the thermographs could not record above 

only at the differences between the control and 46"&, the actual highest temperature achieved is 

solar plot results for August (after treatment), unknown, 111 other studies conducted in warmer 

increases would be evident in calcium (Ca), soils, temperatures of 50°C at a depth of 15 cm 
Table 4. Soil chemical analyses (measured in soil paste, 1:l s o i l t o water) 

for samples taken in control and solar-heated plots in June (before treatment) 

and August 1983 (after treatment) and the following May 1984 at Bessey Nursery. 

~a++ mg/1 M~++ mg ,/ 1 Na+ mg/l K+ 

Control Solar Control Solar Control Solar Control Solar 

June 7.7 8.6 1.8 2.4 2 . 0 2.4 5.4 7,3 

Aug, 12 26 3 4 3 5 8 12 

May 5 1 4 7 12 11 - 6 6 - 

NH&+-R mg/l NO~--K mg/I CI- mqll pH 

Control Solar Control Solar Control Solar Control Solar 

June 0.4 0.7 1.9 3.5 6 5 5.7 5.7 

Aug. 0.6 2.4 7 12 4 5 5.3 5.8 

and 60°C at 5 em were reported (Pullman et al., by spring, probably from blown-in seed. In 

1981b). In the Rocky Mountain Region, nighttime addition, germination of weed seeds in the spring 

cooling by re-radiation may be an important factor may have been higher than in August because any 

in prevention of higher soil temperatures under cold requirement to break seed dormancy would 

the polyethylene. have been satisfied by spring. 

Some studies have linked increased crop growth 

with increases in minerals in the soil solution 

due to solar heating (Katan, 1984). In contrast 

to reports in the literature, in this study soil 

samples from control and solar-heated plots were 

analyzed before, immediately after, and the 

spring following solar heating. Information from 

the additional sampling times helped separate 

seasonal fluctuations and measuring error from 

solar-heating effects. In this study, solar 

heating resulted in measurable increases in Ca 

and NHh-N, but seasonal fluctuations over the 

winter were greater than solar heating effects. 

Measuring error probably accounts for the 

fluctuations in pH, and a portion of the 

fluctuations in the ions. 

These results underscore the danger of taking 

only post-treatment samples as done by previous 

workers. Because a statistical sample is not 

taken for chemical analysis of soil, more than 

one set of samples (e.g. pre-treatment and posttreatment for both control and treatment) must 

be taken. Seasonal variation my exceed any 

apparent change due to treatment, or the soil in 

the sampling areas may have differed before 

treatment . 

Population levels of %thim spp. were signif icantly reduced by solar heating at both nurseries 

but returned to pretreatment levels over the 

winter at Bessey, possibly due to the influence 

of the oat cover crop. There was no winter cover 

crop planted at CSFS. Reduction in population 

of Fusarim spp. were statistically significant 

only at CSFS. Meed populations were also 

significantly reduced by solar heating at both 

nurseries, but returned to pretreatment levels 

Population levels of qythiwn spp. were high and 

of r'usarim spp. and weeds were relatively low at 

the spring sowing of lodgepole pine at Bessey. 

The lodgepole pine showed no beneficial effects 

due to solar heating. Reductions in populations 

of Fusarium spp. by solar heating have not been 

accompanied by improved survival of conifer 

seedlings sown the following spring in other 

studies (Cooley 1983, Cooley 1985). The winter 

cover crop sown immediately after solar heating 

at Bessey did show an increased growth response 

in the solar heated plots compared with that in 

the surrounding control area in November 1983. 

Fall-planted crops would benefit the most from 

the control of weeds and soil-borne plant pathogens by solar heating. 

Solar Heating in Practice 

Both fumigation and solar heating require the 

use of tractors, personnel, and polyethylene 

sheeting; however, with solar heating the health 

hazards and cost of handling the toxic fumigant 

are eliminated. Even partial reduction in the 

annual cost of herbicides and labor for weeding 

makes the solar heating technique attractive. A 

disadvantage of solar heating is that the area 

being treated rmst be out of production for six 

to eight weeks during the summer preceding 

planting. Keeping the polyethylene intact and 

in place for that length of time also constitutes 

an operational difficulty due to wind. 

Solar heating effects on a fall-sown eastern 

redcedar crop are being investigated at Bessey 

Nursery. 
The author thanks Marvin Strachan, Colorado 

State Forest Service; John Hinz, U. S. Forest 

Service; and other Nursery and Forest Service 

personnel who cooperated and assisted with this 

project. This research was part of the author's 

Dissertation: Effects of Solar Heating of Soil 

on Plant Pathogens and Thermotolerant Microorganisms Antagonistic to Pathogenic EFzsarim 

species in Colorado and Nebraska Tree Nurseries, 

University of Colorado, Boulder, 1986. 

Jacobsohn, R.; Greenberger, A*; &tan, J. ; 

Levi, M.; and Alon, H. Control of Egyptian 

broonrape a@gyp$i~a), and othe r 

weeds by means of solar hearing of the soil by 

polyethylene mulching. Weed Sci. 28: 312-31 6 ; 

1980. 

Johnson, D. W.; and Zak, B. Effects of soil 

treatments on fungal populations and ponderosa 

pine seedling survival in an Oregon nursery. 

Plant Dis. &p. hl:43-47; 1977. 

Katan, J. Soil solarization. Ac ta Horticulturae 

152:227-236; 1984. 

LITERATURE CITED 

Ashworth, L. J., Jr.; Gaona, S. A. Evaluation of 

clear polyethylene mulch for controlling 

Verticilzium wilt in established pistachio nut 

groves. fiytopathology 7 2: 243-246; 1982. 

Boyd, R. J. Effects of soil fumigation on 

production of conifer nursery stock at two 

northern Rocky Mountain nurseries. USDA For. 

Serv, Intermt. For. & Range Exp. Stn., Kes. 

Pap. INT-91; 1971, 19 pp. 

Chen, Y. ; and Katan, J, Effect of solar heating 

of soils by transparent polyethylene mulching 

on their chemical properties. Soil Sci. 130: 

271-277; 1980. 

Cooley, S. J. Soil solarization in a forest 

nursery for the control of nusery pests. USDA 

For. Serv, Pacific Northwest Region, For. Pest 

Management Rep; 1983. 15 pp. 

Cooley, S. J. Evaluation of solarization and 

fumigation at the J. J3erbert Stone Nursery. 

USDA For. Serv. Pacific Northwest Region, For. 

Pest Management Rep.; 1985. 16 pp. 

Croghan, C. F.; Grebasch, J, ; and Jacob, R. 

Evaluation of the effectiveness of soil fumigation and solarization on soil-borne organisms 

and seedling production. USDA For, Serv, 

Northeast, Area, For, Pest Management, St. Paul 

Field Office, Field Note 84-6; 1984, 13 pp. 

Forest Service. 1985 U. S, forest planting 

report. USDA For. Serv. Washington Office, 

May 1986. 12 pp, 

Green, R, H. Sampling design and statistical 

methods for environmental biologists. John 

Wiley and Sons, New York; 1979. 257 pp. 

Grinstein, A,; Katan, J. ; Abdul-Razik, A. ; 

Zeydan, 0.; and Elad, Y. Control of Sclerotiwn 

roZf6ii and weeds in peanuts by solar heating 

of the soil. Plant Dis. Rep. 63: 1056-1059; 

1979. 

Worowitz, M.; Regev, Y.; and Herzlinger, G. 

Solarization for weed control, Weed Sci. 

31: 170-179; 1983. 

Hunt, J. C. The forest that men made. Amer. 

For., Nov. andDec., 1965. 12pp. 

Katan, J.; Fishler, G.; and Grinstein, A. Shortand long-term effects of soil solarization and 

crop sequence on Pusariwn wilt and yield of 

cotton in Israel. Yhytopathology 73:1115-1219; 

1983. 

Katan, J.; Greenberger, A.; &on, H.; and 

Gr instein, A. Solar heating by polyethylene 

mulching for the control of diseases caused by 

soil-borne pathogens, Phytopathology 6 6: 6 83-688 

1976. 

Landis, T. D.; Gillman, L. S.; and Hildebrand, 

D. M. Effectiveness of soil fumigation with 

methyl bromide-chloropicrin at Mt. Sopris tree 

nursery, White River National Forest, September, 

1976. USDA For. Serv. Rocky Mt. Region, Biol. 

Evaluation R2-76-15; 1976. 6 pp, 

Mahrer, Y. Prediction of soil temperatures of a 

soil mulched with transparent polyethylene. 

J. Applied Meterol, 18: 1263-1267; 1'379. 

Moreland, D, C. Soil survey of Larimer County 

area, Colorado. USDA Soil Conservation Serv. 

and For. Serv. , in coop. 610. Agric. Ikp. St n. , Map Sheet No. 24; 1980. 

Munnecke, D. E.; and Van Gundy, S. D. Movement 

of fumigants in soil, dosage responses, and 

differential effects. Ann. Rev. Phytopathol. 

17:405-429; 1979. 

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and Landis, T. D. , eds. Forest nursery manual: 

production of bareroot seedlings. Nijhof f /Junk 

Publishers, The Hague; 1984: 193-202. 

Peterson, G. W. Root lesion nematode infestation 

in a plains forest tree nursery. USDA For. Ser 

Rocky Mountain For. and Range Exp. St n, , Re s. 

Note 75; 1962. 2 pp. 

Pullman, G. S.; DeVay, J. E.; and Garber, R. H. 

Soil solarization and thermal death: a 

logarithmic relationship between time and 

temperature for four soil-borne plant pathogens 

Phytopathology 7 1 :959-964; 1981a. 

Pullroan, G. S.; &Vay, J. E.; Garber, R. H.; and 

kinhold, A. R. Soil solarization: effects of 

VertieiZZiumwilt of cotton and soil-borne popu 

lat ions of VerticiZZi urn dahZiae, Pythi urn spp. , E%izizoctonia sozani, and 172ieZaviopsis basieola. 

Phytopathology 7 1:9 54-959; 1981b. 
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survey of Thomas County, Nebraska. USDA Soil 

Conservation Serv. and For. Serv. , in coop. Univ. 

Nebraska Conservation and Serv. Div., Ser. 196 1, 

No. 29, Map Sheet 37; 1965. 

Sokal, R. R.; and Rohlf, F. 3. Biometry; the 

principles and practice of statistics in biological research, 2nd ed. W. N. Freeman and 

Co., San Francisco; 1981, 859 pp. 

Stapleton, J. J.; BeVay, 3. E.; Quick, J.; Van 

Ri jckevorsel, M.; and DeBoer, G. J. Increased 

soluble mineral nutrients in soils as related 

to increased plant growth response following 

soil solarization. Phytopathology 73:814 

(Abstr. A.380); 1983. 

Sutherland, J. R.; and Van Eerden, E. Diseases 

and insect pests in British Columbia forest 

nurseries. Brit. Columbia Minis. For. and Can. 

For, Serv. Joint Rep. No. 12; 1980. 55 pp, 

Zakaria, M. A*; Lockwood, 3. L.; and Filonow, 

A, B. Reduction in p~saritm: population density 

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70:4 95-499; 1480. 
VAIilFIGIHG INSECTS BFFECTItZS QM< REGEBEPdTIZR 

1 / 

EY PRESGRIOEC BLTR~~I NG~' 

21 Susan L . WrightOaks are the most important hardwood trees in 

the eastern U.S. The establishment and survival 

of oak as a major stand compcncnt src aerious 

probiems in the Central and Mid-Atlantic States. 

Forest managers in these states are having 

difficulty reestabiishing oak on the good sites 

that have in the past produced high-quality 

timber. What factors have changed in the last 

50 to 100 years that could account for changes 

in the regeneration of oak forests? - One 

explanation is that the exclusion of wildfire 

has altered the ecology of these stands to the 

detriment of oak regeneration (McGee 1979). 

Research has shown that fire was a natural 

component of many plant cornunities !~einsclzan 

1978!, but effective fire suppression since the 

early 1900's has altered thc structure and 

composition of many of these conczunities. 

Previous research indicates that fire can 

augment oak regeneration, though the mechanisms 

for this are not well understood. Teuke and Van 

Lear !l982) reported that burning increased the 

proportion of oak in the advance regeneration 

pool as well as improved the form of the 

seedlings. Keetch (1944) also reported that an 

intense spring fire in a 25-year-old mixed 

hardwood stand resulted in a coppice stand of 

85% oak. Carve1 and Maxey (1969) found that an 

intense fire in a young mixed-hardwood stand 

converted it to a predominantly oak stand. 

l'presented at the symposium "Current Topics in 

Forest Researchi", held at Gainesville, FLY on 

November 4-6, 19%. 

 usan an I,. Wright, Research Entomologist, U.S. 

Department of Agriculture, Forest Service, 

Northeastern Forest Experiment Station, 359 Main 

Road, Delaware, Ohio 43015 USA 

Abstract--The lack of cak regeneration in many 

areas of tile eastern U.S. has generated interest 

in prescribed burning as a foresr management tool 

to improve the naturai regeneration of oak 

stands. Researchers are stud-;- jlllg the role of 

insects as a faccor in the oak regeneration 

problem. Recsntly ttsy found that a complex of 

insects play a detx-lmental role in all aspects 

of oak regeneration. It is conceivabie that 

burning under the right conditions and at 

appropriate times in the lige cycle of these 

insect pests ~~lr~'ld rerl11re the nitrnfiers of insects 

vd elrainate breeding nabitats, or both. 

Our data indicate that burning may reduce the 

populations of several insect pests of oak 

regenerat ion, including the acorn weevil, 

Conotrachelus posticatus i~oneman) and the sap 

beetle, Stelidota octomaculata (Say). The 

intensity of the burn seems to be critical in 

reducing insect popuiat ions. 

Carve 1 hnci Tryon (1 901) studied the correlation 

between site factors and the amount of oak 

regeneration in a stand. They found that the 

stand hrs~ory, or tile degree of disturbance 

during the past 2C years, was very closely 

correlated with the amoent of oak regeneration. 

They found that grazed, burned, or thinned 

stands possessed a greater reservoir of advanced 

oak regeneration than undisturbed stands. 

Another poorly understood Lactor In the oak 

regeneration problem is the role of insects. 

Researchers are now awsrc of a complex of 

insects that have a detrimental effect on all 

aspects of cak rcgc----+' IllLCLL-l~n. Insects of the 

genus Curculio have been reported by various 

authcrs !~orsey et al. 1962; Gibson 1972, 1982) 

to infest large perccztages of acsrns. ether 

insect groups reported to infest acorns include 

aoths !~ibson 1972, 1982), gall-forming wasps, 

and flies (Gibson 1972) . Insects associated 

with acorns are a sigrliricant factor in acorn 

viability and subscqoent oak seedling 

establishment. Scientists at the USDA Forestry 

Sciences Laboratory in Delaware, Ohio, have 

identified several insect pests of germinating 

acorns and young seedlings, in addition to those 

listed above. The total impact of these insects 

on oak regeneration is believed to be 

significant . 

Research on the control of acorn pests is 

scarce. Dorsey et al. (1962) found that a 

granular application of insecticide distributed 

around the base of oak trees significantly 

reduced infestations of acorns by Curculio spp. 

This is an impractical control method for 

wide-scale use and would control only a few of 

the insect pests of oak regeneration. 

Prescribed burning has been used as an insect 

control technique for several pest species. In 

1912, Webster promoted burning alfalfa fields 
after harvesting for control of the alfalfa 

weevil, Hypera post ica (~yllenhall) (~omarek 

1970) . Sinunons et al. ( 1977) reported an 87.5% 

mortality in populations of the maple leaf 

cutter, Parac lemensia acerifoliella (Pitch), 

after the leaf litter was burned in 2 

maple-heech forest prior to spring emergence of 

the adult moths. Miller (1978) found that 

prescribed burning was a promising tool for 

con t ro l l ing the red pine cone beetle , Conophthortts resinosae Eopkins, and for 

protecting cone crops in seed production areas. 

Research by Williams et al. (19801 demonstrated 

that the exclusion of fire increased the extent 

of Douglas-fir tussock moth [(0rpYia 

pseudotsugata hfc~unnough)l outbreaks, and they 

further suggested that prescribed fire 

represents a biologically sound tool to control 

the extent of future outbreaks. 

While these studies have evaluated prescribed 

burning as a control technique for a specliic 

insect pest, other studies have looked at insect 

populations following prescribed burning. Pktz 

and Farrier (1973) found that annual burning in 

loblolly pine stands in South Carolina resulted 

in significantly lower mesofaunal insect 

populations. Harris and Whitcomb (1974) 

reported that fire seemed to have altered 

populations of some ground beetles , decreasing 

the abundance of some species while increasing 

the abundance of others. In a longleaf pine 

forest, Fellin and Kennedy (1972) observed that 

the number of insects decreased each year during 

3 years of prescribed burning. 

Because of the biology and behavior of many of 

the insect pests of oak regeneration, it is 

conceivable that prescribed burning would have a 

significant effect in limiting these insect 

populations. For instance, the acorn weevil, 

Conotrachelus posticatus ohem em an), which feeds 

and breeds in germinating acorns, spends a major 

portion of its life on the forest floor. This 

insect is found as an adult in both the spring 

and the fall (~ibson 1964), periods when 

prescribed burning is most feasible in eastern 

hardwood forests. The acorn moth, Melissopus 

latiferreanus (~alsin~ham), is present in the 

duff as a larva or pupa for much of the same 

time period (Murtfeldt 1894) and would also be 

susceptible to burning. While the biology of 

some of the lesser known pests of oak 

regeneration is not yet fully understood, it is 

believed that many of these insects do spend all 

or part of their lives on the forest floor and 

would, therefore, be affected by a prescribed 

burn. Included in this group are a sap beetle, 

Steiidota octomaculata (say), and another acorn 

moth, Valentinia glanduella (Riley), both of 

which have been reported to be primary pests of 

sprouting acorns (Galford 1986a). Insect pests 

of oak seedlings, such as the weevil Barypeithes 

pellucidus pe oh ern an), that feed on the leaves, 

stems, and roots of young oaks (Galford 1986b3 

may also be affected by fire. These insects 

spend much of their lives on or in oak seedlings 

and would be eliminated when fire destroys the 

aboveground parts of the seedlings. The oaks 

would resprout, but theoretically the insects 

would be ki 1 led. 

The studies presented here are a preliminary 

evaluation of the effect of prescribed burning 

on insect pests affecting oak regeneration. 

P.IATERIALS AND kgETHODS 

These studies were conducted in con Junct ion 

with two prescribed burns conducted on the 

Athens Ranger District of the Wayne Hoosier 

National Forest in Hocking County, Ohio, in 

April 1984 and April 1985. 

Prescribed Burns 

The 1984 burn involved 48 acres (19.4 ha) of 

uel?-stccked oak-hickory forest. The 

silvicultural objectives of the burn were to 

reduce understory competition and increase the 

proportion of advanced oak reproduction. To 

meet these objectives, a slow, low- to 

moderate-intensity fire was planned. In 

general, the average rate of spread was 5 

chainslhr (ca 100 mlhr), and the average flame 

length was 2 -5 ft (0.76 m) . Bowever, fire 

behavior was inconsistent in some areas because 

of variations in fuel and litter in the burned 

area and the changes in the weather that 

occurred during the 3-hr burn. With this 

particular burn, fire intensities were great in 

several areas and extreme scorch heights 

occurred. 

In 1985, 12 acres (4.9 ha) of similar forest 

land were burned with the same objectives as 

those for the 1984 burn. Although weather 

conditions were identical for both burns 

(average temperature 2z°C and 522 RH), fuel 

moisture was much higher in 1985 than in 1984. 

This resulted in a slow, low-intensity fire. 

The rate of spread of the fire was 3 chainslhr 

(ca 60 m/hr) and the average flame length was 

1.5 ft (ca 0.46 m). 

Unburned areas adjacent to the burned areas 

served as controls in these studies. These 

areas were selected because of similar forest 

type, ground cover, slope, and aspect. 

Sampling Techniques 

Two techniques were used to sample populations 

of known insect pests affecting oak 

regeneration: the baited pitfall trap and the 

collection of leaf litter. The baited pitfall 

trap (~arris and Whitcomb 1971, 2974; Rickard 

1970) was designed to capture the acorn weevil, 

- C. posticatus. Metal coffee cans, 10 cm in 

diameter and 13 cm deep, containing acorns of 
either bur oak (Quercus macrocarpa ~ichx) or 

northern red oak (4. rubra L.) were buried so 

that the open end of the can was level with the 

ground. Each can had a hardware-cloth lid wired 

to the top. Our previous studies had shown that 

- C, posticatus is attracted to acorns and will 

walk or fall into the cans. 

In 1985, the trap was modified, and each can was 

fitted with a screen funnel. The funnel had a 

2-cm flange along the outside circumference of 

the can. Thrs change was made to assure that no 

weevils could leave the cans by crawling up the 

sides. Also, the bottom of the can was removed 

and replaced with screen to allow water to drain. 

In both years, the pitfall traps were located 

ca 4 m from the base of oak trees throughout the 

burned and adjacent unburned areas. Eleven 

pairs of pitfall traps were placed throughout 

the area that was burned in 1984, and an equal 

number of traps was placed in the adjacent 

unburned area. Trap pairs were 1 m apart. The 

spacing between trap sites was at least 25 m. 

In each location, one of the traps of each pair 

contained ca six red oak acorns; the other can 

contained ca six bur oak acorns as the 

attractant source. In the study area that was 

burned in 1985, 25 single pitfall traps were 

located (at least 10 m apart) throughout the 

burned area, and 16 traps were located in an 

adjacent unburned area; all traps were baited 

with bur oak acorns. 

Pitfall trap sites were monitored from April 

through October during 1984 and 1985, and only 

during the months of April and October during 

1986. At weekly intervals during 1984 and 

biweekly intervals during 1985 and 1986, we 

visited all of the trap sites and removed and 

counted any C. posticatus in the cans. We also 

added a fresh acorn to each can and removed any 

that were obviously rotten. 

The second saapling technique involved the 

collection of leaf litter from the forest floor 

(Fel lin and Kennedy 197 2) to sample populations 

of ground-dwelling insects, including 

- C . posticatus . 

Samples of litter Kcre removed 

periodically from beneath oak trees (several 

species) throughout the burned and unburned 

study areas. Each sample, whicb included the 

litter, fermentation, and humus layers (~oover 

and Lunt 1952) of the forest floor, was placed 

in a plastic bag and labeled by sample site. 

Four transects of 10 samples each were taken in 

both the burned and unburned area in 1984. The 

distance between samples was 5 to 10 m, and the 

transects were at least 30 m apart. Two 

transects of 10 samples each were taken in both 

the burned and unburned area in 1985. As in 

1984, the sample sites were at least 5 m apart 

and the transects at least 30 m apart. Every 

4-6 weeks, a samp le 7 5 cm in diameter was taken 

2-3 m from the base of an oak tree, and as the 

study period progressed, each subsequent sample 

was taken around the base of the same trees in a 

clockwise manner. Succeeding samples were at 

least 1 m apart. 

Following cot lect ions in the fie id, samples 

were returned to the lab and placed in cold 

storage (5'~) until the insects could be 

reared from the sample. After removal from cold 

storage, each sample was placed in a fiberboard 

rearing drum. As the litter inside the drum 

dried , the insects dropped or crawled through 

the bottom opening of the drum and were 

collected weekly. Also collected weekly were 

those insects that crawled into a polyethylene 

bottle located near the top on the side of the 

drum. The litter samples were left in the 

drums 4-6 weeks depending on the dryness of the 

sample and the presence of emerging insects. 

Emerging insects were collected and stored in 

alcohol and eventually identified as to family. 

Insects of special interest, such as 

- C. posticatus and M. latiferreanus, were 

identified and counted individually. 

Release-Recapture Studies 

As part of the 1985 burn, we conducted a marked 

release-recapture study of the immediate effect 

of burning on 2. posticatus. One hundred and 

fifty lab-r weevils were marked with 

Tech-Pen Ink w" (Wineriter and Walker 1984) 

and held for 24 hr on acorns until 1 hr before 

the burn. The weevils were divided into three 

groups of 50 each, and each group was released 

on the ground ca 10 m from a pitfall trap site. 

The weevils were then covered loosely with 

leaves and other debris from the forest floor. 

The ground where 5. posticatus was released was 

marked with metal flags so that it would be 

possible after the burn to find the exact 

locat ion where the release occurred. 

RESULTS AFZ DISCUSSION 

1984 Burn 

Pitfall traps--In the first two collection 

periods following the 1384 burn (~pril 25 and 

May 2), fewer 2, posticatus were captured from 

the pitfall traps in the burned area than in the 

unburned area (fig. 1A). This may indicate that 

the burn immediately lowered the number of 

weevils in the burned area. Although 

 he use of trade, firm, or corporation nanes 

in this publication is for the information and 

convenience of the reader. Such use does not 

constitute an official endorsement or approval 

by the U.S. Department of Agriculture or the 

Forest Service of any product or service to the 

exclusion of others that may be suitable. 
differences were not significant (t-test; 

P ( 0.051, we feel that the lack of significance 

was the result of too few samples being taken 

during this collection period. Limited samples 

were taken because the contents of all but two 

of the pitfall traps in the burned areas were 

destroyed by mamals. 

Again during each of the weekly collection 

periods in August, September, and October 1984, 

fewer weevils were captured in the burned area 

than in the unburned area. However, only the 

collect ions of August 22-30 were signif icantly 

different (t-test; P 5 0.05). This reduction of 

the weevil population several months after the 

burn was not exclusively the result of a direct 

kill of the insects by the fire since most of 

the weevils present in the fall were newly 

emerged and were present as larvse underground 

when the burn occurred. Rather it may be due in 

part to the destruction by fire of acorns that 

would have been breeding habitat for the weevils 

present in the spring. Also, the fire destroyed 

much of the leaf litter, and this reduction in 

soil cover could have made the soil surface less 

hospitable to weevils during the hot and dry 

summer months. 

These pitfall traps were again monitored 

throughout 1985 and during April of 1986 to 

determine if the prescribed burn had any effect 

on weevil populations in subsequent years. Very 

few weevils were collected in 1985 from any of 

the pitfall traps, either in the burned or 

unburned areas (fig. 1~). These reduced catches 

may be indicative of an overall decrease in the 

indigenous 2. posticatus population, which may 

have been the result of a poor acorn crop in 

1984. These numbers seem to indicate that the 

1984 burn had limited impact on C, posticatus 

populations in the following year. However, the 

extremely low catches and lack of any clear 

trends (fig. 1B) make it difficult to arrive at 

any definite conclusions. 

The number of weevils collected in the pitfall 

traps during April of 1986 was also low (avg. 

3.2 weevils/trap in control area vs 1.9 

weevils/trap in burned area). These differences 

were significant (t-test; P ( 0.05) and may 

indicate that 2 years after the burn, fewer C. 

posticatus were present in the burned area 

compared to the unburned area. 

- S. octomaculata, another pest affecting oak 

regeneration, is attracted to acorns and was 

collected in the pitfall traps in April of 

1986. Significantly more (t-test ; P ( 0.05) 

- S. octomaculata were collected from pitfall 

traps in the unburned area than the burned area 

(223 vs 112 individuals, respectively). 

Previous opportunities to collect this sap 

beetle had been missed in 1984 and 1985 because 

it was not yet recognized as a significant pest 

of germinating acorns. 

Litter samples--The number of C. posticatus 

collected in the litter samples is shown in 

figures 2A and 2B. The results weve similar to 

those for pitfall traps. More weevils were 

captured in the unburned area than in the burned 

area immediately following the burn in 1984 

(~~rll 19 collection) (fig. 2A). The same 

results were observed In late summer and fail. 

These differences between the burned and 

unburned areas were significant for the late 

sumer (August 6) and fall (~eptember 13 and 

November 7) collections (t-test; P 0.10). 

Litter samples were again collected throughout 

1985 and in April of 1986 from the same sites as 

in 1984. More G. posticatus were reared from 

fitter sampled in the unburned area than in the 

burned area throughout spriw and summer of 

1985, The differences were sigaif icant in the 

April, July, and August collections (fig. 2B). 

There are apparent discrepancies betweeo data 

from the pitfall trapping and from litter 

sampling when results for 1984 and 1385 are 

compared. On me hand, litter collected in the 

unburned area contained more G, posticatus than 

the burned area during the spring and summer 

months. Further, the results from litter 

samples indicate that the 1984 prescribed burn 

may have agfected the spring population of 

- C. posticatus 1 year after the burn occurred. 

But there seems to be no difference between 

burned and unburned areas in catches at pitfall 

traps during the second year following the 

burn. 

One possible explanation may be that pitfall 

traps measure activity as well as density of 

insect populations. In an inhospitable area, 

such as one that has been burned or one that has 

few acorns, the weevils may wander more widely 

in search of places to feed or breed, increasing 

the likelihood of being trapped, and thus 

leading to the erroneous impression that the 

population density is greater. Also, the number 

of C. posticatus collected from the pitfall 

traps was Lower in 1985 than in 1984 in both the 

burned and unburned areas, but comparable 

numbers of C, posticatus emerged from the litter 

sa~ples in each of the 2 years. 

These differences seem to indicate that the 

pitfall traps may have been less efficient in 

1985 and 1986 than in 1984 in terms of capturing 

- C, posticatus, Minor changes in the trapping 

system between 1984 and 1985, such as the 

addition of the funnel insert did not seem to 

affect trap catches. However, we conducted a 

biweekly collection schedule in 1985 instead of 

a weekly schedule as in 1984. This change may 

have resulted in suboptimum conditions for the 

acorns that were used as the attractant source. 

The biweekly collection schedule, possibly along 

with other climatic factors that affected the 

decomposition of the acorns in the traps, may be 
the cause of the apparent discrepancies in trap 

catches between 1984 and 1985. 

Collection of other insects from litter 

samples--Several thousand individuals, 

representing 146 families from 14 orders, were 

reared from the litter samples collected before 

and after the 1984 prescribed burn. The general 

trend is a decrease in the number of individuals 

in all families of insects in the burned area 

compared to the unburned area. Thirteen 

families that were apparently most affected by 

the burn, along with the number of individuals 

collected in the unburned and burned areas, are 

listed in Table 1. In litter collections taken 

after the burn (collection periods 2, 3, and 41, 

the number of listed individuals collected in 

the burned area was less than the number in the 

unburned area. 

The Curculionidae family includes C. posticatus 

and other weevil pests of acorns. The family 

Nitidulidae includes the species 

- S. octomaculata, which has been discovered to be 

a pest on germlnatlng acorns (~alford, in press). 

The Cynip idae inc lude gal 1-forming 

wasps. This family includes several species 

that damage developing acorns in the crown of 

oak trees (~ibson 1972, 1982). The gall-forming 

f lles of the famlly Cecldomyldae may also 

Include species of insects that form galls in 

developing acorns. 

Phasmidae and Buprestidae are two other 

families of insects not listed in Table 1 that 

are known pests affecting oak regeneration that 

also appear to be affected by the burn. 

Phasmidae (walking sticks) defoliate trees and 

can be especially serious on young seedlings (11 

individuals collected from the control area 

following the burn vs 4 individuals in the 

burned area), The Buprestidae (fiat-headed 

borers) family includes at least one species of 

insect in the genus Agrilus that bores through 

the stems of young seedlings (2 individuals 

collected from the control area vs 0 from the 

burned area). 

Although it is apparent from this generalized 

information that burning did have an effect on 

insect populations in general, informat ion on 

specific known pests is not available (with the 

exception of G. posticatus) because of the lack 

of suitable sampling procedures. 

1985 Burn 

Pitfall trapping and litter sampling conducted 

before the April 12, 1985, burn indicated that 

fewer C. posticatus were present in both the 

burned and unburned areas in 1985 than in 1984. 

After the prescribed burn, results from the 

pitfall trap sampling showed no change between 

the populations of C, posticatus in the burned 

and unburned areas. However, more weevils were 

found in the burned area than in the unburned 

area during each of the collection periods 

throughout the spring and fall. 

Unlike the results of pitfall trapping, there 

were significantly fewer C. posticatus collected 

in the litter samples from the burned area than 

from the unburned area (6 weevils vs. 11 from 

the 15 April collection and 8 weevils vs. 17 

from the 29 May collection). 

In our release-recapture study, we returned 1 

hour after the burn to the three locations where 

marked 5. posticatus were released before the 

burn. Upon close examination or the area, we 

found numerous live weevils beneath the scorched 

litter, apparently unharmed by the fire. No 

dead weevils were observed at any of the 

locations, and no marked weevils kere collected 

in subsequent litter coilections or pitfall txap 

coilections in the area. The 1985 sampling 

data, along with the finding that marked 

- C. posticatus survived the burn, led us to 

believe that the 1985 burn had very little 

effect on 5. posticatus populations. These 

findings seem to demonstrate that for a 

prescribed burn to be effective in reducing 

populations of C. posticatus in an area, the 

intensity of the fire must be moderate to high, 

and most of the litter must be destroyed in the 

process. 

SUIaIARY A&D CONCLUSIONS 

I have attempted to evaluate the impact of 

prescribed burning on C. posticatus and other 

litter-inhabiting insects by measuririg the 

relative abundance of insects in burned and 

unburned areas. I hoped to determine if fire 

would effectively reduce insect numbers by 

examining absolute numbers of insects present in 

the burned area and in an unburned control area, 

Ir studies of this type, we niust realize that 

the heat of the fire may be less important than 

later ecological and other changes that may 

ultimately reduce, or in some other way, affect 

insect popuiat ions. Many insects lack the 

ability to adapt to the xeric conditions on the 

forest floor following a fire. Also, insects 

may not be able to withstand the lack of food or 

breeding material, or the greater temperature 

fluct.uations on the forest floor after a fire 

(Ahlgren 1974). This may be the case when fire 

destroys acorns on the ground that serve as the 

breeding habitat for C. posticatus and other 

insects. In addition, fire destroys the litter 

where these insects seek refuge, thus making 

burned areas inhospitable until litter levels 

return to normal depths. These types of 

ecological changes would be difficult, if not 

impossible, to measure in short-term 

experiments. 
The role of insects in the oak regeneration 

problem is a complex one and any control 

technique developed to limit their impact needs 

to be broad. Fire is a natural environmental 

regulator of animal populations, particularly 

insects (Komarek 1970). The preliminary 

evidence presented here indicates that 

prescribed burning may have potential as a 

s ilvicultural ly acceptable procedure to manage 

some insect pests of oak regeneration. 

LITERATURE CITED 

Ahlgren, I. F. 1974. The effect of fire on soil 

organisms. & T.T. Kozlowski and C. E. 

Ahlgren, eds., Fire and Ecosvstems, Academic 

Press, New York, pp. 67-72. 

Carvel, K. L. and W. R. Maxey. 1969. Wildfire 

adversely affects composition of cove hardwood 

stands. West Virginia Univ., Agric. Exp. Stn. 

Bull. 2(2): 4-5. 

Carvel, K. L. and E. H. Tryon. 1961. The effect 

of environmental factors on the abundance of 

oak regeneration beneath mature oak stands. 

For. Sci. 7: 98-105. 

Dorsey, C. K., E. H. Tyron, and K. L. Carvel. 

1962. Insect damage to acorns in West Virginia 

and control studies using granular systemic 

insecticides. J. Econ. Entomol, 55: 885-888, 

Fellin, D . G. and P . C . Kennedy. 1972. 

Abundance of arthropods inhabiting duff and 

soil after prescribed burning on forest 

clearcuts in northern Idaho. U.S. Dep. Agric., 

For. Serv., Intermountain For. and Range Exp. 

Stn., Res. Note INT-162. 8 pp. 

Galford, J. R. 1986a. Primary infestation of 

sprouting chestnut, red, and white oak acorns 

by Valent inia ~landulella (~e~idoptera : 

~lastobasidae). Ent. News. 97: 109-112. 

Galford, J.R. 1986b. The Weevil Barypeithes 

pellucidus (Coleoptera: ~urculioidae) feeds on 

northern red oak, Quercus rubra, seedlings. 

Ent. News. 97: 113-114. 

Galford, J. R. In press. A paper to be presented 

at the Sixth Central Hardwood Forest 

Conference, Knoxville, TN. February 24-26, 

1987. 

Gibson, L. P. 1964. Biology and life history of 

acorn-infesting weevils of the genus 

Conotrache lus (Co leoptera: ~urculionidae) . Ann. 

Entomol. Soc. Amer. 57: 521-526. 

Gibson, L. P. 1972. Insects that damage white 

oak acorns. U.S. Dep. Agric., Northeast. For. 

Exp. Stn., Res. Pap. NE-220. 7 p. 

Gibson, L. P . 1982. Insects that damage 

northern red oak acorns. U.S. Dep. Agric., 

Northeast. For. Exp. Stn., Res. Pap. ME-492. 

6 P* 

Harris, D. L. and W. H, Whitcomb. 1971. Habitat 

relationship and seasonal abundance of four 

species of Erarthrus (Coleoptera:Carabidae), 

Coleopt. Bull. 25(2): 67-72. 

Harris, D. L. and W. H. Whitcomb. 1974. Effects 

of fire on populations of certain species of 

ground beetles (Co 1eoptera:Carabidae) . Fla . Entomoi. 57: 97-103. 

Heinselman, M. L. 1978. Fire in wilderness 

ecosystems. & Wilderness management. J. C. 

Hendee, G. H. Stankey, and R. C. Lucas (eds.). 

U.S. Dep. Agric., Misc. Pub. No. 1365. 

Washington, D .C . pp . 249-278. 

Hoover, M. D. and H. A. Lunt. 1952. A key for 

the classification of forest humus types. Soil 

Sci. Soc . Am. Proc. 16: 368-70. 

Keetch, J. J. 1944. Sprout development on 

once-burned and repeatedly burned areas in the 

Southern Appalachians. U.S. Dep. Agric., 

Appalachian For. Exp. Stn., Tech. Note 59. 

3 PP* 

Komarek, E. V. 1970. Insect control--Fire for 

habitat management. Proc . Tall Timbers Conf . , Ecol. Anim. Contr. Habitat Manage., Vol. 2. pp, 

157-171; 

McGee, C.E. 1979. Fire and other factors 

related to oak regeneration. In Proc. 

Regenerating oaks in upland hardwood forests. 

Harvey A. Holt and Burnell C. Fisher (eds.) 

Purdue Univ., Dept, of Forestry and Natural 

Resources. West Lafayette, IN. pp 75-81. 

Metz, L. J. and M. H. Farrier. 1973. Prescribed 

burning and populations of soil mesofauna. 

Environ. Entomol. 2: 433-440. 

Miller, W. E. 1978. Use of prescribed burning 

in seed production areas to control red pine 

cone beetle . Environ. Entomol . 7 : 698-702. 

Murtfeldt, Mary E. 1894, Acorn insects, primary 

and secondary. U.S. Dep. Agric. Div. Ent. 

Insect Life. 6: 318-324. 

Rickard, W. H. 1970. Ground dwelling beetles in 

burned and unburned vegetation. J. Range 

Manage. 23: 293-294. 

Simmons, G. A*, J. Mahar, J. K. Kennedy, and 

J. Ball. 1977, Preliminary test of prescribed 

burning for control of maple leaf cutter 

(~epidoptera: Incurvar idae) . Great Lakes 

Entomo 1, 10: 209-210. 
Teuke, N. K. and D. H. Van Lear . 1982. 

Prescribed burning and oak regeneration in the 

southern Appalachians. Georgia For. Con., Res . Pap. 30. 11 pp, 

Wineriter, S. A. and T. J. Walker. 1384. Insect 

marking techniques: durability of materials. 

Entonol. News. 95: 117-123. 

Williams, J. T. , R. E. Kartin, and S. G. 

Pickford. 1980. Silvicultural and fire 

management implications from a timber type 

evaluation of tussock moth outbreair areas. 

Proc. 6th Natl. Conf. Fire, Forestry, and 

Meteorology., Soc . Amer . Forest. pp. 191-196. 

Figure 1 A- Conotrachelur, postlcatus 

collected from pltfall traps 

1111 su~;~~flon dot & s 1984 

Unburned 

I - @Ienfflcantly dlfferont 1Pj.06, 1-tee$) 

Flgure 1 B- Conotrachelus postlcatus 

collected from pltfall traps 

111 guz;f;ctfon dates 1085 

Unburnod 

+ - ~~enlflesntly dittorent (~s.06. $-teat) 

Ftgure 2B- Conotrachelur ortlcatur 

collected In Iltthr 

4/10 5/29 6/26 7/25 8/29 9/26 10/30 - Goiiect~on dates 1985 Burned 124 Unburned 

-algnltic8ntiy different (PS.30. 1-tost) 

Flgure 2A- Conotrachelus orticatus 

collected in ittp-i 

4/2 4/19 5/14 6/20 8/6 9/13 11/7 

.II BuF,"d';ction dates 1984 

Unburned 

-elgnilicantly dlfferont fPj.10. 1-teat) 

DIPTERA C~~YIDAE 3 1 RONON 1 DAE CETOPHILIDAE 

IARIDAE 
Tomy Bailey, Silviculturist 

USDA Forest Service, Region 8 

Route 2, Box 701 

Silver Springs, FL 32670 

9041 625-2520 

Jill Barbour, Technical Forester 

Owens-Illinois 

P.O. Drawer A 

White Springs, FL 32096 

9041397-2171 

SYMPOSIUrYi ON CURRENT TOPICS IN FOREST RESMCH: 

EMPHASIS ON CONTRIBUTIONS BY WOMEN SCIENTISTS 

Gainesville, Florida 

November 4-6, 1986 

Jane Barrows-Broaddus, Research Plant Pathologist 

USDA Forest Service, Southeastern Station 

Forestry Sciences Laboratory 

Carlton Street 

Athens, GA 30602 

4041546-2435 

Ann M. Bartuska, Program Coordinator 

Acid Deposition Program 

Southern Commercial Forest Research Cooperative 

School of Forest Resources 

1509 Varsity Drive 

N. C. State University 

Raleigh, NC 27606 

9191737-3520 

Joyce K. Berry, Associate in Research 

School of Forestry and Environmental Studies 

205 Prospect St., Sage Hall 

Yale University 

New Haven, CT 06511 

2031436-4360 

Caroline Bledsoe, Research Professor 

Mycorrhizal Physiology 

College of Forest Resources AR-10 

University of Washington 

Seattle, WA 98195 

2061545-0954 

Sandra E. Brown, Assistant Professor of Ecology 

Department of Forestry 

110 Mumford Hall 

University of Illinois 

1301 W. Gregory St. 

Urbana, IL 61801 

2171333-1643 

Marilyn A. Buford, Research Forester 

USDA Forest Service, Southeastern Station 

2730 Savannah Highway 

Charleston, SC 29407 

8031556-4860 

Ann E. Carey, Soil Scientist 

National Program Manager, Forest Response Program 

USDA Forest Service, P.0, Box 2417 

Room 610-A, RPE 

Washington, DC 20013 

7031235-8195 

Kathy Carter, Associate Professor of Forest 

Resources 

Department of Forest Biology 

201 Nutting Hall 

University of Maine 

Orono, HE 04469-0125 

2071581-2855 

Harriet H. Christensen, Research Social Scientist 

USDA Forest Service, Pacific Northwest Station 

4043 Roosevelt Way, ME 

Seattle, WA 98105 

2061442-7817 

Betty Culmer 

USDA Forest Service 

P.O. Box 2417 

Room 904, RP-E 

Washington, DC 20013 

Margaret S. Devall, Plant Ecologist 

USDA Forest Service, Southern Station 

Room T-10210 

701 Loyola Ave. 

New Orleans, LA 70113 

5041589-4551 

Connie Dickard 

USDA Forest Service 

Region 8 

227 N, Bronough St., fj4061 

Tallahassee, FL 32301 

Mary Ellen Dix, Research Entomologist 

USDA Forest Service, Rocky Mountain Station 

Forestry Sciences Laboratory 

East Campus 

University of Nebraska 

Lincoln, NE 68583-0822 

4021471-5178 

Arlene T. Doyle, Research Ecologist 

USDA Forest Service, Southeastern Station 

Department of Forestry 

Clemson University 

Clemson, SC 29632 

803/656-4865 

R. Kasten Dumroese 

University of Idaho 

Research Nursery 

714 East I'D" St. 

Moscow, ID 83843 

2081883-0943 

Irene Durbak, Forester 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Drive 

Madison, WI 53705-2398 

6081264-5600 
Mary L. Duryea, Assistant Professor of Forestry 

Department of Forestry 

School of Forest Resources and Conservation 

118 Newins-Ziegler Hall 

University of Florida 

Gainesville, FL 32611 

9041392-1791 

Pam Edwards, Research Forester 

USDA Forest Service 

Timber and Watershed Laboratory 

Parsons, WV 26287 

3041478-2000 

Dixie Ehrenreich 

Laboratory of Anthropology 

University of Idaho 

Moscow, ID 83843 

2081885-6754 

Katherine C. Ewel, Professor of Forestry 

Department of Forestry 

School of Forest Resources and Conservation 

118 Newins-Ziegler Hall 

University of Florida 

Gainesville, FL 32611 

9041392-1850 

Mary Ann Fajvan, Instructor 

Forest Resources 

Penn State University 

110 Ferguson Building 

University Park, PA 16802 

8141863-0401 

Anne S. Fege, Staff Research Physiologist 

USDA Forest Service 

Timber Management Research (Rosslyn) 

Box 2417 

Washington, DC 20013 

7031235-8200 

Sandra Jo Forney, Forest Archeologist 

USDA Forest Service, Region 8 

227 N. Bronough Street 

Suite 4061 

Tallahassee, FL 32301 

9041681-7338 

Leslie D. Fortner, Laboratory Research Technician 

Tidewater Agriculture Experiment Station 

8968 Gates Road 

Suffolk, W 23437 

8041569-9347 

Thomas F. Geary 

International Forestry Staff 

Training and Education 

USDA Forest Service 

14th and Independence Ave., S.W. 

Rosslyn Plaza, P.O. Box 2417 

Arlington, VA 20013 

7031235-2432 

Nada Gogala, Professor 

Institute for Biology 

Askerceva 12 

Ljubljana, Yugoslavia 332611 

Sally M. Haase, Research Forester 

USDA Forest Service, Rocky Mountain Station 

Forestry Science Laboratory 

700 S. Knowles Drive 

Flagstaff, AZ 86001 

6021527-7315 

Sharon G. Haines, Section Leader 

Soils Research 

International Paper Company 

Sauthlands Experiment Forest 

Route 1, Box 571 

Bainbridge, GA 31717 

912/246-3642 

Terry Haines, Forester 

Forest Resource Law and Economics 

USDA Forest Service, Southern Station 

Room T-10210, 701 Loyola Ave. 

New Orleans, LA 70113 

5041589-6652 

David M. Hamilton, Forester (oRA) 

USDA Forest Service 

Region 8, Osceola District 

Route 7, Box 423 

Lake City, FL 32055 

9041752-2577 

Linda Hardesty, Assistant Professor 

University of Washington 

Box 2023-CS 

Pullman, WA 99164 

509/335-6632 

Aurelia B. Harris, Economist 

USDA Forest Service, Southeastern Station 

P.O. Box 12254 

Research Triangle Park, NC 27709 

919/541-4205 

Awatif E. Wassan, Professor of 

Forestry and Biological and Agricultural 

Engineering 

School of Forest Resources 

N. C. State University, Box 8002 

Raleigh, NC 27695-8002 

9191737-2891 

Jacqueline L. Haymond, Extension Forester 

Instructor in Forestry 

Department of Forestry 

College of Forest and Recreation Resources 

272 Lehotsky Hall 

Clemson University 

Clemson, SC 29634-1003 

8031656-4831 

Diane M. Hildebrand, Research Plant Pathologist 

USDA Forest Service, Rocky Mountain Station 

11177 W. 8th Ave. 

Lakewood, CO 80225 

3031236-9542 

Deborah B. Hill, Assistant Extension Professor 

Department of Forestry 

University of Kentucky 

Lexington, KY 40546-0073 

6061257-7610 
Janet Winchee 

USDA Forest Service 

Region 8 

227 N. Bronough St., 114061 

Tallahassee, FL 32301 

Karen L. Hood, Forester 

USDA Forest Service, Southeastern Station 

P.O. Box 2680 

Asheville, NC 28802 

704/259-0616 

Denise C, Ingram, Forester 

USDA Forest Service, Southeastern Station 

P.O. Box 12254 

Research Triangle Park, NC 27709 

9191541-4221 

Pamela A. Jakes, Project Leader 

USDA Forest Service, North Central Station 

1992 Folwell Ave. 

St. Paul, MN 55108 

6121642-5279 

Shirlea A. Johnson, Forest Technician 

USDA Forest Service, Southeastern Station 

P.O. Box 2680 

Asheville, NC 28802 

7041259-0606 

Peggy Knowles, Assistant Professor 

Department of Biology 

School of Forestry 

Lakehead University 

Oliver Road 

Thunder Bay, Ontario 

Canada P7B 5E1 

8071345-2121 Ext. 672 or 732 

Susan V. Kossuth, Principal Plant Physiologist 

USDA Forest Service, Southeastern Station 

1143 Fifield Hall 

University of Florida 

Gainesville, FL 32611 

9041371 -4360 

Carol L. Link, Mathematical Statistician 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Dr. 

Madison, WI 53705-2398 

6081264-5731 

Jim Loften 

USDA Forest Service 

Region 8 

227 N. Bronough St., #4061 

Tallahassee, FL 32301 

William G. Luppold, Project Leader 

USDA Forest Service, Northeastern Station 

Box 152 

Princeton, WV 24740 

Arnett C. Mace, Jr., Director 

School of Forest Resources and Conservation 

118 Newins-Ziegler Hall 

University of Florida 

Gainesville, FL 32611 

9041392-1791 

Judith A. Maxwell, Assistant Professor 

School of Natural Resources 

Ohio State University 

2021 Coffee Road 

Columbus, OH 43210 

6341422-226s 

Joan 6. McAndrew, Program Analyst 

Forestry Inventory and Economic Research Staff 

USDA Forest Service 

P.O. Box 2417, Room 4210-S Bldg. 

Washington, DC 20013 

2021382-1724 

Monica McCarthy, General Engineer 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Dr. 

Madison, WI 53705-2398 

6081264-5626 

Carolyn McQuattie, Research Plant Pathologist 

USDA Forest Service, Northeastern Station 

311 N. Washington Street 

Delaware, OH 43015 

6141369-4475 

Jessie A. Micales, Research Plant Pathologist 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Dr. 

Madison, WI 53705 

6081264-5645 

Lorraine Mineo, Lecturer in Biology 

Department of Biology 

Lafayette College 

Easton, PA 18042 

2151250-5465 

Ricky E. Morgan, Supervisory Forester 

USDA Forest Service 

Region 8 

Route 2, Box 701 

Silver Springs, FL 32688 

9041625-2520 

Mary S. Mumford, Forester 

USDA Forest Service 

Region 9 

2727 N. Lincoln Road 

Escanaba, MI 49829 

9061786-4062 

James F. Naylor, Jr., District Ranger 

USDA Forest Service 

Region 8, Osceola District 

Route 7, Box 423 

Lake City, FL 32055 

9041752-2577 

John H. Ohman, Deputy Chief 

Research 

USDA Forest Service 

Washington, DC 20014 

2021447-6665 
Deborah Page-Dmroese, Soil Scientist Trainee 

USDA Forest Service, Intermountain Station 

1221 S. Main St. 

Moscow, ID 83843 

2031882-3557 

Marcia Patton-Nallory, Research Engineer 

USDA Forest Service 

Forest Products Laboratory 

One Gifford Pinchot Drive 

Madison, W1 53705-2398 

6081264-5671 

R. Max Peterson, Chief 

USDA Forest Service 

Washington, DC 20250 

2021655-4000 

Edith Petrick, Forester 

USDA Forest Service 

Region 8 

P.O. Box 1066 

Crawfordville, FL 32327 

9041222-9549 

Christine Pytel, Assistant Director for 

Support Services 

USDA Forest Service, Northeastern Station 

370 Reed Road 

Broomall, PA 19008 

215/461-3009 

Nancy A. Pywell, Assistant Professor 

of Natural Resources Education 

Department of Forestry 

School of Forest Resources and Conservation 

118 Newins-Ziegler Wall 

University of Florida 

Gainesville, FL 32611 

904/392-5420 

Radha Ranganathan 

Rayallapur Document Foundation to aid 

Industrial Recovery 

6 Linacre College 

Oxford OX1 3JA, UK 

0865-53603 

C.P. Patrick Reid, Chairman 

Department of Forestry 

School of Forest Resources and Conservation 

118 Newins-Ziegler Hall 

University of Florida 

Gainesville, FL 32611 

9041392- 1850 

Rachel D. Robertson, Assistant Professor 

Arizona State University 

204 Dixie Gmage Wall 

Tempe, AZ 85287 

6021965-5059 

Ginger Rutherford, Coordinator 

Southfornet 

USDA Forest Service 

University of Georgia 

Science Library 

Athens, GA 30602 

4041546-2477 

Sandhya Smarasinge, Graduate Student 

Forest Products 

Virginia Polytech Institute and State University 

35 Northview Apts. 

110 Northview Drive 

Blacksburg, VA 24060 

7031961-0958 

Krist Scheidt, Student 

Oklahoma State University 

1020 E. Virginia #10 

Stillwater, OK 74075 

4051377-5951 

Jerry A. Sesco, Director 

USDA Forest Service 

Southeastern Forest Experiment Station 

P.O. Box 2680 

Asheville, NC 28802 

7041259-0758 

Harold G. Shenk, Forester 

USDA Forest Service 

Region 8 

Route 2, Box 701 

Silver Springs, FL 32688 

9041625-2520 

Laura C. Snook 

Researcher, INIREB 

D.F. Student, School of Forestry 

and Environmental Studies 

Yale University 

244 Edwards Street 

New Haven, CT 0651 1 

2031777-4288 

Pauline C. Spaine, Research Plant Pathologist 

USDA Forest Service, Southeastern Station 

Forestry Sciences Laboratory 

Carlton Street 

Athens, GA 30602 

4041546-2455 

Thomas C. Spencer, Supervisory Forester 

USDA Forest Service 

Region 8, Osceola District 

Route 7, Box 423 

Lake City, FL 32055 

9041752-2577 

Nellie M. Stark, Professor 

Forest Ecology 

School of Forestry 

University of Montana 

Missoula, MT 59812 

4061243-2913 

Donna Stewart, Student 

Oklahoma State University 

601 Willham North 

Stillwater, OK 74077 

4051624-8681 

Terry L. Stolz, Forester 

USDA Forest Service 

P.O. Box 400 

Kolly Springs, MS 38635 

6011252-2633 
Robert C. Thatcher, Assistant Director 

USDA Forest Service 

Southeastern Station 

P.O. Box 2680 

Asheville, NC 28802 

7041259-0421 

William B. Weaver, Associate Librarian 

Hume Library 

University of Florida 

Gainesville, FL 32611 

904/392-1934 

Patti Webb, Pathologist 

Fruit Crops Departmebnt 

1143 Fifield Hall 

University of Florida 

Gainesville, FL 30611 

904/392-4711 

Hazel Wetzstein, Assistant Professor 

Department of ;forticulture 

University of Georgia 

Athens, GA 30602 

4041542-2471 

Joy Woolfson de Noboa, Student 

Catholic University 

Veintimilla 521 

Quito, Ecuador 

Susan L. Wright, Research Entomologist 

USDA Forest Service 

Northeastern Station 

359 Main Road 

Delaware, OH 43015 

614/369-4472 

Tricia Wurtz 

Graduate %aching Fellow 

Department of Biology 

University of Oregon 

Eugene, OR 97403 

5031686-4944 

Carleen Yocum 

Forester 

USDA Forest Service 

Route 1, Box 179 

Whitmire, SC 29178 

8031276-4810