Beyond 2001: A Silvicultural

Odyssey to Sustaining Terrestrial

and Aquatic Ecosystems

Proceedings of the 2001 National Silviculture Workshop,

May 6-10, Hood River, Oregon

United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical

Report

PNW-GTR-546

July 2002
Compilers

Sharon Parker is a strategic planning and program analyst, USDA Forest Service, Vegetation Management and Protection Research, P.O. Box 96090, Washington, DC; and Susan Stevens Hummel is

a research forester, Forestry Sciences Laboratory, P.O. Box 3890, Portland, OR 97208-3890.

Papers were provided ready for printing by the authors, who are responsible for the content and

accuracy. Opinions expressed may not necessarily reflect the position of the U.S. Department of

Agriculture.

The use of trade or firm names in this publication is for reader information and does not imply endorsement by the U.S. Department of Agriculture of any product or service.
Beyond 2001: A Silvicultural Odyssey to Sustaining

Terrestrial and Aquatic Ecosystems

Proceedings of the 2001 National Silviculture

Workshop, May 6-10, Hood River, Oregon

Sharon Parker and Susan Stevens Hummel

Compilers

U.S. Department of Agriculture

Forest Service

Pacific Northwest Research Station

Portland, Oregon

General Technical Report PNW-GTR-546

July 2002
Abstract

Parker, Sharon; Hummel, Susan Stevens. 2002. Beyond 2001: a silvicultural odyssey to sustaining terrestrial and aquatic ecosystems—proceedings of the 2001 national silviculture workshop,

May 6-10, Hood River, Oregon. Gen. Tech. Rep. PNW-GTR-546. Portland, OR: U.S. Department

of Agriculture, Forest Service, Pacific Northwest Research Station. 114 p.

Preface

The 2001 National Silviculture Workshop was held in Hood River, Oregon, and hosted by the Mt. Hood

National Forest, the Gifford Pinchot National Forest, and the Pacific Northwest Research Station. The

Washington Office Vegetation Management and Protection Research and Forest and Grassland staffs

are ongoing sponsors of the biennial workshop, which began in 1973 in Marquette, Michigan. The

general purpose of the workshop is to provide a forum for scientists and land managers to exchange

ideas and information and to develop opportunities for future collaboration. The 2001 workshop focused on the role of silviculture in supporting wildlife habitat and riparian management objectives. This

topic was chosen to emphasize current issues in forestry and to underscore the important contribution

of silviculture to ecosystem management. Papers were solicited on projects that demonstrated the use

of silviculture in achieving wildlife and fish management goals. This document contains the papers that

were offered at the 2001 workshop, and are grouped according to four themes: wildlife, vegetation,

aquatic systems, and social systems. Authors are presented in the order in which papers were presented at the 2001 workshop.

Nancy Lankford, Forest Silviculturist on the Mt. Hood National Forest, and Bob Obedzinski, Silviculturist on the Gifford Pinchot National Forest, were instrumental in organizing the 2001 workshop. The

planning committee included Frank Burch, WO-FM; Sharon Friedman, WO-VMPR; Fred Zensen and

Grant Gunderson, Pacific Northwest Regional Office; Andrew Carey, Peter Bisson, Connie Harrington,

and Susan Stevens Hummel, Pacific Northwest Research Station.

S. Friedman, Washington, DC

S. Hummel, Portland, OR

S. Parker, Washington, DC

February 2002
Contents

Chapter 1

Wildlife

1 Using Individual Tree Selection Silviculture to Restore Northern Goshawk Habitat: Lessons from a

Southwestern Study

Wayne D. Shepperd, Lance A. Asherin, and Carlton B. Edminster

1 Introduction

2 Methods

2 Results

6 Discussion

9 References

10 Development and Maintenance of Northern Spotted Owl Habitat in the Gotchen LateSuccessional Reserve of the Gifford Pinchot National Forest, Washington

Rolando R. Mendez-Treneman

10 Issues

11 The Setting

14 Objectives

14 Methods

14 Results

15 Discussion

18 Acknowledgments

18 References

Chapter 2

Vegetation

21 Application of Landscape Objectives to Stand-Level Silviculture: Blue River, Oregon

John H. Cissel, James H. Mayo, Steven L. Garman, and Frederick J. Swanson

21 Introduction

23 Objectives

23 Adaptive Management Model

23 Landscape Plan

23 Fire History

23 Landscape Management Group

26 Evaluation

26 Stand-Level Prescriptions

26 Model Description

28 Analysis

28 Evaluation

29 Results

30 Monitoring

30 Conclusions

30 Acknowledgments

30 References
32 Historical Stand Reconstruction in Ponderosa Pine Forests to Guide Silvicultural Prescription

Richy J. Harrod, Bradner H. McRae, and William Hartl

33 Restoring the Longleaf Pine Ecosystem: The Role of Fire

James P. Barnett

33 Introduction

33 Longleaf Pine Ecosystem

34 The Historical Role of Fire

34 Decline of the Longleaf Pine Ecosystem

34 Restoring the Longleaf Pine Ecosystem

35 Reforestation Technology

35 Role of Fire

35 Education and Commitment

36 Determination of Success

36 Conclusions

36 References

38 Silvicultural Options for Multipurpose Management of West-Side Pacific Northwest Forests

Stephen E. Reutebuch, Constance A. Harrington, Dean S. DeBell, David D. Marshall, and

Robert O. Curtis

38 Introduction

38 Past Research and Management Experience in the Douglas-fir Region

39 Silvicultural Options Studies in the West-Side PNW Region

39 Early Development Options—Alternative Silviculture in Young Douglas-fir Plantations

41 Midrotation Options—Olympic Habitat Development Study

43 Regeneration Harvest Options—Silvicultural Options for Harvesting Young-Growth Forests

45 Discussion and Conclusions

45 Acknowledgments

46 Metric Equivalents

46 References

47 Snag Frequencies 50 Years After Partially Cutting Interior Ponderosa Pine Stands

William W. Oliver

47 Introduction

48 The Study Area

48 Methods

49 Results

49 Discussion

50 Acknowledgments

50 References
52 Damage to Residual Trees from a Commercial Thinning of Small-Diameter Mixed-Conifer Stands

in Northeastern Washington

Ann E. Camp

52 Introduction

53 Methods

53 Study Site

54 Harvesting Equipment and Methods

54 Data Collection

55 Results

55 Damage to Trees Specifically Marked for Retention

55 Discussion

57 Conclusion

58 Acknowledgments

58 References

59 Lake States Aspen Productivity Following Soil Compaction and Organic Matter Removal

Douglas M. Stone

59 Introduction

60 Methods

60 Stand and Site Conditions

60 Design and Treatment

61 Measurements and Analyses

62 Results and Discussion

62 Soil Compaction

63 Organic Matter Removal

65 Summary and Management Implications

65 Soil Compaction

65 Organic Matter Removal

65 Acknowledgments

65 References

68 Reserve Tree Method Produces Abundant Aspen Regeneration and Increases Early Growth

Douglas M. Stone

68 Introduction

69 Traditional Management

69 Methods

70 Results and Discussion

71 Summary and Management Implications

72 Application

72 Acknowledgments

72 References

73 Appendix

73 Common and Scientific Names of Trees and Shrubs
74 Understory Vegetation Development Following Commercial Thinning in Southeast Alaska:

Preliminary Results from the Second-Growth Management Area Demonstration Project

Richard R. Zaborske, Richard N. Hauver, Michael H. McClellan, and Thomas A. Hanley

74 Introduction

77 Methods

79 Results

80 Discussion

81 Acknowledgments

81 References

82 Appendix

Common and Scientific Names of Plants, Trees, and Animals

83 Artificial Regeneration of Northern Red Oak and White Oak on High-Quality Sites: Effect of Root

Morphology and Relevant Biological Characteristics

Paul P. Kormanik, Shi-Jean S. Sung, Stanley J. Zarnoch, and G. Thomas Tibbs

83 Introduction

84 Background

84 Biological Constraints

85 Acron Production

85 Nursery Protocol

86 Seedling Evaluation

88 Pre and Post Site Maintenance

89 Current Trends of ITRB Research

90 Conclusions

90 Metric Equivalents

90 References

Chapter 3

Aquatic Systems

93 Does Red Alder Enhance Wildlife, Aquatic, and Fisheries Resources in Young-Growth Western

Hemlock-Sitka Spruce Forests of Southeast Alaska?

Robert Deal, Mark Wipfli, Adelaide Johnson, Toni De Santo, Paul Hennon, and Thomas Hanley

93 Introduction

96 Approach

97 Methods

98 Wood Production, Vegetation, and Tree Disease

98 Aquatic and Riparian Ecology

98 Terrestrial Invetebrates

98 Wildlife

99 Fish

99 Geomorphic and Landscape Processes

99 Research Objectives

100 Management Implications

100 Forest Vegetation

100 Hydrology and Gemorphology

100 Aquatic and Riparian Ecology

100 Terrestrial Invertrebrates

100 Wildlife Ecology

100 Acknowledgments

100 References
Chapter 4

Social Systems

104 Combining Social and Ecological Needs on Federal Lands: A Global Perspective

Marlin Johnson

104 Introduction

107 Shifting the Paradigm

108 Conclusion

108 Acknowledgments

108 References

Summary

110 The Future of Silviculture Research—Thoughts From the Yale Forestry Forum

Sharon T. Friedman and James M. Guldin

110 Introduction

111 Methods

111 Results

111 Plenary Session

111 Sustainability

112 Flexibility

112 Rigor

112 Roundtable Discussions

113 Discussion

114 Reference
Chapter 1

Wildlife
1

Using Individual Tree Selection Silviculture to Restore

Northern Goshawk Habitat: Lessons from a Southwestern

Study

Wayne D. Shepperd, Lance A. Asherin, and Carlton B. Edminster

Authors

Wayne D. Shepperd is a research forester and Lance A. Asherin is a forester, Rocky Mountain Research

Station, 240 West Prospect Road, Fort Collins, CO 80526; and Carlton B. Edminister is a research silviculturist, forester, and project leader, Rocky Mountain Research Station, 2500 South Pine Knoll, Flagstaff,

AZ 86001.

Abstract

Stem-mapped data from six 10-acre uneven-aged Ponderosa pine (Pinus ponderosa var. scopulorum

Laws.) growth plots located on a highly productive site on the North Kaibab Plateau in Arizona were used

to examine the distribution of vegetation structural stages recommended for management of Northern goshawk and species in its food web. Seedling/sapling and old-forest stages were found to be lacking at the

sub-stand level. Future growth of selected groups was projected to estimate residence in various structural

stages under differing stocking conditions. Stagnation of untreated densely stocked groups prevented them

from reaching old-forest condition. Young groups quickly grew to mature stages. Continual management for

all structural conditions at a fine scale will be needed to maintain recommended goshawk habitat conditions. We present a conceptualized model of how this might be accomplished.

Keywords: Northern goshawk habitat, vegetative structural changes, ponderosa pine.

Introduction

Management for the northern goshawk (Accipiter

gentilis atricapillus) has profoundly changed silviculture in the western U.S., particularly in the

Southwest, where the goshawk has been listed as

a sensitive species since 1982 (Dewhurst et al.

1995). Management recomendations designed by

an interdisciplinary team of scientists to improve

goshawk habitat in the Southwest have been in

place for several years (Reynolds et al. 1992).

These recommendations identify forest structural

characteristics for goshawk nesting, post-fledging,

and foraging habitats combined with habitats of

goshawk prey and recommend a mix of vegetative

structural stages (VSS) to be maintained across

landscapes through time. Six VSS classes are defined in table 1.

The recommendations recognize that maintaining

the desired mix of VSS’s across landscapes will

require “some form of stand replacement and density control,” but do not specify specific silvicultural

methodology to achieve it. Establishing and maintaining the desired mix of VSS’s across a landscape as each grows into a more mature class

while at the same time regenerating areas to VSS1

is no small task. It is further complicated by the

necessity to maintain high canopy cover percentages (>60 percent) within clumps in portions of

VSS 4-6.

Dewhurst et al. (1995) and Long and Smith (1999)

have subsequently addressed this issue and suggested methodology to address the problem at

landscape scales. These approaches are reminiscent of a large-scale application of group selection

silviculture utilizing a combination of area control

with intervening density control to achieve the desired spatial, structural, and age class mixes. We

were intrigued by these papers because neither

presented specific data on groups or clumps of

trees existing within VSS’s or what the expected

growth (and therefore longevity) of the respective

VSS’s containing such groups might be.
2

Methods

A continuing uneven-aged growth study on the

Kaibab Plateau north of the Grand Canyon offered

us the opportunity to explore the details of how

stocking in small groups or clumps might affect the

maintenance of VSS’s at larger scales in ponderosa pine forests. Six 10-acre units were established in 1993 in a mesa-top forest (36.54° N.

112.33° W.). All of these forests contained a range

of diameter and age classes and were very productive with an average Site Index of 95 (base age

100). Two complete replications of a control unit

and two uneven-aged individual tree selection units

were laid out. Basal areas of the two treated units

in each replication were subsequently reduced to

average basal area stocking levels of 61 to 74

ft2 • ac-1 by using marking guidelines that specified

irregular tree spacing and maintenance of clumps.

From 1998 to 2000, we mapped the location of

all trees in the entire study. Figure 1a is an exact

three-dimensional reproduction of Control Unit 1

drawn by using the Stand Visualization System

(McGaughey 1997). Treated Unit 3 is shown in

figure 1b. The multistoried, irregularly spaced composition of these forests is readily apparent. These

10-acre units are certainly not landscapes, and

cannot represent VSS’s on the 2-4 acre scales

recommended for goshawk habitat (Reynolds et al.

1992). However, they are diverse enough to represent growth conditions within groups and clumps

of trees within a spatially diverse ponderosa pine

forest on the Kaibab Plateau. The control units

represent conditions that existed prior to implementation of the goshawk recommendations, and the

treated plots offer the opportunity to examine future

growth following uneven-aged silviculture treatments that might be applied at larger scales to

manage for goshawk. The spatially-mapped data

from the units offered an opportunity to examine

growth dynamics of small groups of trees that could

represent various VSS classes at larger scales in

southwestern ponderosa pine.

To quantify the variability in structure and stocking

in each of the units, we divided each into a 6 x 6

grid of 36 plots (each 0.27 acre in size), calculated

stem densities and quadratic mean diameters

(QMD), and assigned each plot into a VSS class

according to the diameter distribution presented in

table 1. An algorithmic relationship developed from

even-aged ponderosa pine thinning plots in northern Arizona (data on file Rocky Mountain Research

Station) was used to estimate canopy cover requirements specified for VSS 4-6 (Reynolds et al.

1992):

Crown Cover = -57.44 + 25.5047 * LN(BA)

where: BA = Basal area (ft2

 • ac-1)

We then picked subplots of interest and projected

their growth forward in time using the SUPPOSE

interface to the Forest Vegetation Simulator (FVS )

(Crookston 1997). The Central Rockies/Southwestern FVS variant was used to estimate changes in

structure and VSS’s through time. We ran the

model without any growth, mortality, and disease

modifiers, using tree dimensions, conditions and

damages that were measured on the subplots.

Trees that had grown into some treated subplots

between 1994 and 2000 were included to gage the

effects that ingrowth after a manipulation treatment

would have on groups. We also simulated the effects that thinning would have on the rate of

change within groups, including the effects of new

regeneration that would be stimulated by the treatment (using our observed responses following the

1993 thinning as a guide).

Results

All of the 10-acre units exhibit the varied structure

illustrated in figures 1a and 1b. Boxplots of basal

area distributions within the units (fig. 2) indicate

that while the average basal areas in the two control units is 125 ft2

 • ac-1, basal areas of the 36 subplots within each of these units ranged from 40-190

ft2 • ac-1. Average basal areas (measured in 1994)

Table 1–The classification of vegetative structural stages (VSS) based on stand

quadratic mean diameter (QMD) at breast height.

VSS 1 2 3 4 5 6

DBH (inches) 0-1 1-5 5-12 12-18 18-24 24+
3

Figure 1–Graphical depiction of two 10-acre study units drawn from stem-mapped tree data (A)

Control Unit 1; (B) Treated Unit 3 after uneven-aged thinning.

 A

 B
4

Figure 2–Boxplots of basal area distributions for Control Units 1

and 6 vs Treated Units 2-5 (n = 36 0.277-acre subplots in each

unit). Means (labeled “ba”) appear at the bottom.

of the treated units ranged from 61-74 ft2 • ac-1, but

subplots ranged from 19-135 ft2 • ac-1. Stem density

boxplots indicate that the two control units are quite

dissimilar (fig. 3). Unit 6 contains a wide range of

stem densities, while those in Unit 1 are more uniform, even though both have exactly the same

basal area. The ranges of stem densities in the

treated units also varied (fig. 3). Stem densities in

Units 3, 4, and 5 are much less variable than the

control plots. The range of stem densities in Unit 2

was similar to that of Control Unit 1, even though

the treatment had reduced the basal area by 40

percent.

VSS’s were assigned to each of the 36 subplots

within each unit for comparison to the recommended VSS distributions for goshawk foraging

areas in ponderosa pine (fig. 4). The VSS distribution for subplots in all six of the units show considerable deviation from recommended conditions

(fig. 4). As is typical of existing southwestern forests, neither of the control or treated units contain

grass/forb/shrub (VSS1), or old-forest (VSS6)

structural conditions. Instead, VSS3 and VSS4

conditions predominate. Openings created by the

treatments were not large enough to convert any

subplots to VSS1, although we did locate and measure numerous seedlings in some subplots in 2000.

Not enough time has elapsed since the study was

installed to grow any VSS5 subplots to VSS6, however.

Figure 3–Boxplots of the stem density distributions for Control

Units 1 and 6 and Treated Units 2-5 (n = 36 0.277-acre

subplots in each unit). Means appear at bottom.

Figure 4–Distribution of VSS’s in Units 1-6 and the

recommended VSS distribution guideline for northern

goshawk habitats (Reynolds et al. 1992).
5

We selected specific subplots to investigate how

stocking at small spatial scales might influence the

progression from one VSS to the next. Several

scenarios were run in FVS:

1. To see how quickly an open, mature forest in

VSS5 might grow to VSS6 on this highly productive site we selected Unit 4, Subplot 31,

an open stand containing 22 trees ac-1 with a

basal area of 40 ft2 • ac-1 and a QMD of 18.4

inches. FVS projected that growing the existing

stocking forward in this subplot would allow it

to reach VSS6B (QMD > 24.0 inches, BA = 67

ft2 • ac-1) in 35 years and VSS6C (>60 percent

crown cover) in 75 years (fig. 5a).

2. To contrast how a densely stocked VSS5C

(>60 percent crown cover) group might behave,

we chose Unit 1, Subplot 5, which contained

79 trees ac-1 with a basal area of 164 ft2 • ac-1

and a QMD of 19.5 inches. FVS predicted that

this subplot would take 100 years to grow to

VSS6C (fig. 5b). At that time, it would then contain a basal area of over 200 ft2

 • ac-1and have

a QMD of only 24.0 inches. Achieving this condition would be highly unlikely because both

the initial stocking condition and the resulting

stagnated condition would be highly susceptible to attack by Mountain Pine Beetle

(Dendroctonus ponderosae Hopk.).

Figure 5–FVS projection of

Quadratic Mean Diameter (QMD)

and percent crown cover for (A) a

mature open group; (B) a mature

heavily stocked group. Vertical lines

denote VSS boundaries.

Unit 4 Plot 31

0.0

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6

3. Moving to the younger end of the VSS spectrum, we selected Unit 2, Subplot 5, one of only

three VSS2 subplots in the six units. We

wanted to examine how such sapling-sized

groups might persist on this highly productive

site. FVS predicted that this subplot would

grow to VSS3 (QMD >5 inches) in only five

years and exceed 120 BA in three decades

(fig. 6a), indicating a need for thinning. Because this subplot was open and surrounded

by seed bearing trees, 187 new ingrowth seedlings ac-1 had appeared on it between 1993

and 2000. We modeled the effect that this additional stocking would have on future growth

by re-running the previous projection with

these trees included. This doubled the time to

grow to VSS3 to 10 years, but the subplot exceeded 140 BA in the third decade. Clearly,

VSS1 and VSS2 will not persist long on this

highly productive site.

4. Given the apparent need for periodic thinning,

we wanted to see if a densely stocked small

sawlog VSS4 group could achieve VSS6 without any intervention. We used data from Unit 1,

Subplot 6, (QMD = 13.1, BA = 165 ft2 • ac-1)

and ran the FVS model for 400 years without

achieving VSS6 (fig. 6b)! Thinning this group

from below to BA 100, FVS projected it would

quickly grow to VSS6 within 25 years (fig. 7a).

Using observed ingrowth from 1993 to 2000,

we decided to model a second scenario where

we would grow the original Unit 1, Subplot 6 for

100 years, thin it as before, then add 112 new

seedlings ac-110 years later. The inclusion of

ingrowth prevented the group from growing to

VSS6 (fig. 7b), primarily because the numerous

smaller trees lowered the QMD, stagnated, and

did not grow large enough for the overall stand

to achieve VSS6. This reinforces the recommendation to manage clumps of trees as more

or less even-aged (Reynolds et al. 1992).

Discussion

This exercise clearly illustrates that average stand

data does not necessarily reflect the actual conditions under which trees are growing in the irregularly spaced clumpy conditions thought to be

favored by northern goshawks. The existence of

non-uniform growing conditions needs to be addressed when attempting to establish and maintain

the spectrum of VSS’s recommended for Goshawk

habitat. Several factors need to be considered

when planning silvicultural activity in such landscapes.

The time needed to progress from one VSS class

to another will vary based on stocking at the small

scale of clumps, where tree density and competition influence growth. Trees in heavily stocked

groups will grow slowly and remain at similar sizes

(and thus VSS) for long periods of time. They will

also be more stressed and likely be susceptible to

insect attack.

Trees in open-spaced groups or widely spaced

clumps will grow fast, and move into larger VSS

classes quickly. Open-spacing will also allow new

seedlings to establish, which if not controlled

through periodic under burning or thinning, will

create a dense sapling understory and move the

group or clump into a two-aged forest condition

which is undesirable for goshawks and prey. Including the new understory in stocking calculations

(which must be done because the young trees influence overall site productivity) will cause the

QMD to drop, moving the group into a smaller VSS,

even though the group still contains some very

large trees.

On good sites, openings regenerated into VSS1

will move into VSS3 within three decades. This

happens at a much faster rate than VSS5 and

VSS6 portions of the landscape become decadent

and need replacement. Therefore, some VSS3 and

VSS4 groups will need to be harvested to create

sufficient openings to maintain the recommended

10 percent of the landscape in VSS1 and 10 percent in VSS2. If natural regeneration is prolific (as

we have observed it to be on this good site), precommercial thinning or under burning will be necessary to create spatial diversity and maintain a

healthy condition for the groups to grow into larger

VSS’s.

In conclusion, managing southwestern ponderosa

pine forests for northern goshawk habitat is not

merely a question of harvesting trees in a manner

that will create the recommended mix of structural

conditions within goshawk territories. If our study

site is typical of conditions existing at larger scales

in southwestern landscapes, additional openings

will be needed to create VSS1, which is currently

lacking. These in turn will have to be allowed to

grow into VSS2, which are also currently lacking.
7

Unit 2 Plot 5

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 A

Unit 1 Plot 6

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 B

Figure 6–FVS projection of Quadratic Mean Diameter (QMD) and percent crown cover for: (A) a

young sapling group; and (B) a densely stocked small sawlog group left unthinned. Vertical lines

denote VSS boundaries.
8

Figure 7–FVS projection of Quadratic Mean Diameter (QMD) and percent crown cover for a densely stocked small sawlog

group thinned at 10 years (A), and thinned at 100 years with new seedling ingrowth at 120 years (B). Vertical lines denote

VSS boundaries.

Unit 1 Plot 6 

Thinned 10 years later

0

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Unit 1 Plot 6 with ingrowth Thinned 100 years later

 added new ingrowth in 20 years

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9

At the same time, some existing VSS5 groups will

need thinning so they can grow into the critical

VSS6, which again is currently lacking. If this

weren’t complicated enough, both commercial and

non-commercial thinning and prescribed burning

will need to be done simultaneously to some other

VSS groups to maintain them in a condition beneficial to the goshawk. In short, as recommended in

Reynolds et al. (1992), our study verifies that a lot

of continuous silvicultural activity will be needed to

establish and maintain the desired mix of VSS’s for

optimal northern goshawk habitat conditions.

Figure 8 presents our conceptualized model of how

the process of managing goshawk habitat might

work. We do not feel that this would be an impossible task, but rather one which will require intensive silviculture on a fine scale as opposed to the

landscape-scale management schemes that have

been previously proposed. Ignoring the growth

dynamics that are operating at fine scales within

irregularly structured forests will only decrease the

chances of maintaining the mix of structural conditions that are needed at larger scales in northern

goshawk habitats.

References

Crookston, N.L. 1997. Suppose: an interface to

the forest vegetation simulator. In: Teck, R.;

Moeur, M.; Adams, J., comps. Proceedings, forest vegetation simulator conference. Gen. Tech.

Rep. INT-GTR-373. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 7-14.

Dewhurst, S.M.; Covington, W.W.; Wood, D.B.

1995. Developing a model for adaptive ecosystem management. Journal of Forestry. 95:35-41.

Long, J.N.; Smith, F.W. 2000. Restructuring the

Forest: Goshawks and the restoration of southwestern Ponderosa Pine. Journal of Forestry.

98:25-30.

McGaughey, R.J. 1997. Visualizing forest stand

dynamics using the stand visualization system.

In: Proceedings of the 1997 ACSM/ASPRS annual convention and exposition. Bethesda, MD:

American Society for Photogrammetry and Remote Sensing (4):248-257.

Reynold, R.T.; Graham, R.T.; Reiser, M.H. [and

others]. 1992. Management recommendations

for the northern goshawk in the southwestern

United States. Gen. Tech. Rep. RM-217. Fort

Collins, CO: U.S. Department of Agriculture,

Forest Service, Rocky Mountain Forest and

Range Experiment Station. 90 p.

Figure 8–Conceptual model of silvicultural

activities needed to maintain fine-scale

structure in landscapes managed for northern

goshawk. Scheduling of activities would depend

on site productivity and other factors.
10

Development and Maintenance of Northern Spotted Owl

Habitat in the Gotchen Late-Successional Reserve of the

Gifford Pinchot National Forest, Washington

Rolando R. Mendez-Treneman

Author

Rolando R. Mendez-Treneman is a district wildlife biologist, Mt. Adams Ranger District, Gifford Pinchot

National Forest, 2455 Highway 141, Trout Lake, WA 98650.

Abstract

Conservation of late-successional and old-growth forest ecosystems is a key objective of the Northwest

Forest Plan (Plan). The Plan specifies a spatial array of Late Successional Reserves (LSRs) to help

achieve this objective. Under the Plan, management options within LSRs are limited to the maintenance or

development of spotted owl (Strix occidentalis caurina) habitat. Forests constituting spotted owl habitat on

the east side of the Cascade Range in Washington and Oregon are more stressed for moisture than are

forests in LSRs on the west side of the crest. The absence of disturbance, such as forest fire, has resulted

in a greater proportion of late-successional forest stands. These stands have a greater proportion of

shade-tolerant tree species, the majority of which is grand fir (Abies grandis). The grand fir in the Gotchen

LSR is late-successional in nature and provides habitat for the northern spotted owl. Spotted owl habitat is

at risk because of tree mortality. LSR function and legacy tree structure may also be at risk because of

stand replacement crown fire. The legacy trees exceed 150 years in age. Nest sites in the Gotchen landscape are closely associated with this legacy structure. The trajectory of a substantial portion of the grand

fir forest in the Gotchen LSR is continued tree mortality and increasing fuel loading. The purpose of this

paper is to introduce a stand-scale treatment that will (1) maintain spotted owl foraging habitat, (2) increase

the likelihood of stand recovery to late successional condition, (3) decrease the likelihood of crown fire,

and (4) decrease spruce budworm (Choristoneura occidentalis) risk.

Keywords: Spotted owl habitat, grand fir forest, late-succesional reserves, Gotchen LSR, spruce budworm.

LSR contains spotted owl habitat, which is in poor

health and has a declining probability of persistence (USDA FS 2001). Tree stress is resulting

from a drought of the last two to three decades

(High 2001) and endemic forest pathogens

(Obedzinski 2001, Forsberg 2000). Multi-century

old legacy trees are at risk due to competition

stress from the more abundant grand fir. Legacy

trees are also at risk of loss via forest fire. The

1997 Forest Assessment (USDA FS 1997) expressed the concern for the Gotchen LSR that the

combination of relatively dry environment, abundance of fire intolerant tree species, and increasing

levels of forest pathogens would pose significant

risk of catastrophic stand replacing fire. Under

NWFP guidelines, forest silviculture and other forest management options within LSRs are limited to

activities that would maintain or restore habitat for

Issues

The 1994 Northwest Forest Plan (NWFP) was established with the intent of protecting and enhancing conditions of late-successional and old-growth

ecosystems as habitat for northern spotted owls (a

federally listed species) and other old-forest organisms. The NWFP, designated by U.S. Department

of Agriculture, Forest Service (USDA FS) and U.S.

Department of Interior, Bureau of Land Management (BLM), is a network of Late Successional

Reserves (LSRs) across the range of the northern

spotted owl on national forests and BLM lands.

Gotchen is one of the LSRs in this network. It is

located on the eastern flanks of the Cascade

Range in the Gifford Pinchot National Forest of

Washington. A substantial portion of the Gotchen
11

the northern spotted owl. A management expectation is that the Gotchen LSR continue to provide

spotted owl habitat for at least the existing six pairs

(Cox 2001).

This report explores active management of stand

structure of foraging quality spotted owl habitat in

the Gotchen LSR. This foraging quality habitat is

decreasing canopy cover, canopy closure, and

vertical diversity as tree mortality progresses. On

the existing trajectory and within 5-10 years, these

stands are expected to change spotted owl habitat

type from the existing foraging quality to non-suitable. The primary management objective is the

prevention of loss of spotted owl habitat. Secondary objectives are to (1) increase the likelihood of

stand recovery to late-successional condition, (2)

decrease the likelihood of crown fire, and (3) decrease spruce budworm risk. The management

question is, “how much and what kind of change in

stand structure can be implemented and still maintain spotted owl habitat?”

The Setting

The Gifford Pinchot National Forest (GPNF) covers

1.5 million acres in southwest Washington (fig.1)

and is located within the Southwest Washington

Cascades physiographic province. On the north

flank of the GPNF, is the Western Washington Cascades province, and on the east flank is the Yakima

province. Management direction for the GPNF is

established by the Gifford Pinchot National Forest

Land and Resource Management Plan, as

amended by the NWFP (USDA FS 1994).

The NWFP established nine LSRs, which cover

447 thousand acres of the GPNF (fig. 2). Two of

the LSRs on the GPNF, Peterson and Gotchen,

occur on the east side of the Pacific Northwest

Cascades crest. East side LSRs face a drier environment than on the west side of the crest and this

results in different management issues. The

Gotchen LSR, on the east side of the crest, is the

driest of the GPNF LSR network.

The Gotchen LSR covers 15,169 acres and spans

an elevation range of 2,375-5,525 feet. The most

abundant 350 feet elevation class is the 3,775-

4,125 feet class followed by the 4,125-4,475 feet

class. The dominant aspect is southerly, and

slopes are gentle (<10 percent) for most of the

Figure 1—Project area in southwest Washington.

Figure 2—Gotchen Late-Successional Reserve in relation to the

Gifford Pinchot National Forest LSR network.
12

LSR. Stream courses drain to the south-southwest

into the White Salmon River. A precipitation gradient exists in which an average of 90-100 inches

occur in the northwest and 40-50 inches per year

occur in the southeast. Soils, especially in the

southern two-thirds of the LSR, have a high

volcanic ash content and low soil moisture holding capacity.

The wildlife habitat type for the Gotchen LSR is the

“Eastside Mixed Conifer Forest” (Chappell et al.

2001). Chappell et al. (2001) reports that this wildlife habitat type occupies about 4.6 million acres in

the state of Washington and makes up most of the

continuous montane forests of the inland Pacific

Northwest. Three Forest Zones (Topik 1989) occur

in the Gotchen LSR. The Grand Fir Zone occupies

86 percent of the LSR, and the remaining 14 percent in the higher elevations of the LSR is occupied

by the Sub-Alpine and Mountain Hemlock forest

zones. Grand fir forest within the Gotchen LSR is

generally dense and closed multi-story stands, with

ponderosa pine (Pinus ponderosa) and Douglas-fir

(Pseudotsuga menziesii) forming the legacy and

over-story position of the canopy. Grand fir occupies the co-dominant, intermediate, and suppressed portions of the canopy. Other tree species

present include western white pine (Pinus

monticola), western larch (Larix occidentalis),

lodgepole pine (Pinus contorta), quaking aspen

(Populus tremuloides), and Oregon white oak

(Quercus garryana). “Upland Aspen Forest”

(Chappell et al. 2001) is scattered within the

Gotchen LSR as small patches and is in decline

as a function of senescence and or shading. Of the

tree species in the Gotchen LSR, Oregon white oak

is the least abundant and has a patchy (usually

less than a dozen trees per patch) distribution.

As shown in figure 3, the Understory Reinitiation

(UR) (Oliver and Larson 1996) structural stage

occupies 75 percent of the Gotchen LSR

(Hessburg 2001). The UR stage has a large tree

(diameter at breast height, dbh >25") canopy cover

of <30 percent, and seedling/sapling (<5" dbh)

cover >10 percent, and pole-small-medium tree

(dbh 5 to 25") cover >60 percent. The Stand Initiation (SI) stage exists when large tree cover is <30

percent, seedling/sapling cover >10 percent, and

the pole-small-medium tree cover is <20 percent.

The Stem Exclusion (SE) stages have a large tree

cover of <30 percent and seedling/sapling cover of

<10 percent. In the SE stage, a closed-canopy

condition exists when canopy cover for the polesmall-medium tree component is >70 percent. Old

forest stands have large tree cover >30 percent.

The Young-forest Multi-story (YFMS) exists when

large tree cover is <30 percent, seedling/sapling

cover >10 percent, the pole-small-medium tree

cover is >20 percent, and small (9-16" dbh) or medium (16-25" dbh) is >10 percent. Legacy trees

(generally > 36" dbh and more than 150 years old)

are a unique habitat element (O’Neil et al. 2001)

present in low quantities and with wide distribution

across the Gotchen landscape. Legacy trees became established prior to fire suppression efforts.

Those legacy trees that exist today were excluded

from extensive selective harvesting of large oldgrowth ponderosa pine and Douglas-fir during the

1940s through the 1970s.

Figure 3—Forest structure stage distribution for the

Gotchen LSR.
13

Spotted owl habitat within the Gotchen LSR is not

unlike habitat described in other places on the east

side of the Pacific Northwest Cascades crest. The

current condition and distribution of LSR spotted

owl habitat reflects almost a century of fire suppression, timber harvest, and spruce budworm.

Two to three tree cohorts are present with the majority being in the 60-90 year-old class. The second

most common age class would be the 100-150 year

olds, then the greater than 150. Grand fir is the

most abundant species in the youngest cohort.

Douglas-fir and ponderosa pine comprise the vast

majority of the older age classes. Fifty-six percent,

8,553 acres, of the Gotchen LSR is typed as spotted owl habitat (fig. 4). Of that total spotted owl

habitat, 82 percent is foraging quality, and the remaining 18 percent is of the nesting quality. Spotted owl surveys and systematic monitoring of nest

sites in the Gotchen LSR have been conducted

over the last 10 years. Six spotted owl nest sites

are known of in the Gotchen LSR: Gotchen, Smith

Butte, Big Tree, Buck Cr., Crof, and Ground. None

of the known six spotted owl nest sites falls within

nesting quality habitat. The nest site is defined as

including the nest tree and an area of about 0.5

acres around the nest tree. That none of the nest

sites fall within what is typed as nesting quality

habitat likely reflects two aspects of habitat typing.

First, the actual nest site is not necessarily representative of the stand in which the nest site is located (Everett et al. 1997). The nest site is often

a coarse pocket within a stand. The coarseness is

due to the presence of large trees and down logs,

which are legacy structure carried over from the

previous stand. Second, aerial photographs are

used in typing forests using stand scale resolution.

We do not actually know how and or why a spotted

owl selects specific areas to use. Spotted owls

appear to use at least a finer level of resolution in

“typing” their habitat than we do in our stand measuring and typing.

Since 1992, the six spotted owl nest sites in the

Gotchen LSR have been part of a demographics

study focused on spotted owls on the east side of

the Pacific Northwest Cascades. Monitoring includes yearly visits to each nest site during which a

determination is made of which spotted owls are

present, what they are doing, and how many young

are being raised. Spotted owls at each of the sites

have unique leg bands, which allow for field identification of individual owls. The sex of each owl, its

banding location, and when the owl was banded

can be determined. This base data has been used

to determine site productivity and owl movement.

Emigration, immigration, and within LSR movement

have been documented. The Gotchen is adding

(“source”) individual spotted owls to the population.

Spotted owls have demonstrated strong site and

pair fidelity though changes have been observed.

The same stand and same individual tree are used

for nesting and roosting each year. This remains

even when there has been a change in the particular owl using a nest site. Pairs tend to stay together

but occasionally one of the pairs moves to another

site. There has also been the case of two males

being present with one female at a reproductive

site.

Tree disease and insects shape the Gotchen landscape. Over the last century, endemic root disease

is suspected to have spread along with conifer

(particularly grand fir) abundance and distribution.

The greater amount of conifers in the Gotchen LSR

increases the likelihood of root-to-root spread of

root disease (Filip 1998). Compacted soils in the

Gotchen LSR resulted from ground based logging

systems of 60 years ago, and these compacted

soils show limited levels of recovery (High 2000).

Spruce budworm has been defoliating portions of

the LSR since at least 1994 (Willhite 1999). The

budworm outbreak extends beyond the limits of the

LSR covering thousands of acres especially to the

east on Yakima Indian Reservation land. Budworms

Figure 4—Spotted owl habitat (shaded) and nest site (red dots)

distribution in the Gotchen LSR.
14

effectively defoliate grand fir, the most abundant

conifer species in the Gotchen landscape, although

Douglas-fir has also been affected. Grand fir is the

most abundant dead and dying species across the

landscape. The distribution of this mortality varies

from individual pockets of 6-12 trees to the majority

of a stand being dead. Ground fuels are accumulating as dead tops and limbs fall to the forest floor.

The thickets of small grand fir growing in the understory have undergone extensive defoliation from

spruce budworm. The risk is increasing that under

the right conditions, these thickets will serve as

“ladder fuels” conducting a ground fire up into the

crown. Once a fire starts in a densely stocked forest with widespread defoliated and dead trees, the

potential for crown fire spread increases rapidly.

East Cascades forest fires in 1994 altered forest

habitat in LSRs for northern spotted owls by an

average of 55 percent (Gaines et al.1995). Gaines

et al. (1995) reported fewer spotted owls occupying

and reproducing at these activity centers than in

previous years.

Objectives

This report explores active management of foraging quality spotted owl habitat in the Gotchen LSR.

As tree mortality progresses in foraging quality

spotted owl habitat, canopy cover, canopy closure,

and vertical diversity decline. On the existing trajectory and within 5-10 years, this foraging quality

spotted owl habitat is expected to become unsuitable. The primary management objective of this

investigation is the prevention of loss of spotted

owl habitat. Secondary objectives are to (1) increase the likelihood of stand recovery to late successional condition, (2) decrease the likelihood of

crown fire, and (3) decrease spruce budworm risk.

The management question is, “how much and what

kind of change in stand structure can be implemented and still maintain spotted owl habitat?”

Methods

I reviewed literature addressing spotted owl habitat

on the east side of the Pacific crest in Washington.

I located evidence of spotted owl use in the

Gotchen LSR. The evidence was in the form of

observed (audio and or visual) spotted owl activity

including nesting, roosting, territorial displays, and

foraging. I related spotted owl activity evidence to

specific forest stands, then used Region 6 stand

examination procedures (USDA FS 1989) to

sample forest conditions at stands with spotted owl

use. Stand structure and species composition were

sampled via a regular grid of plots. Variable-radius

plots were used with a BAF40 prism to quantify

structure for trees >5" dbh. Hundredth-acre fixed

radius plots were used to quantify structure for

vegetation <5" dbh. Stand data were used to build

tree-list files for analysis in Landscape Management System (Oliver 2001). To facilitate comparison to an existing spotted owl habitat study

(Buchanan 1996), I grouped stand structure data

into the same dbh classes used by Buchanan

(1996). The proportion of basal area distribution

within each diameter class reflects the average,

plus or minus one standard deviation, of all stand

examination data.

Results

Buchanan described forest structure at spotted

owl nest sites from the east slope of the Cascade

Range in Washington (Buchanan 1991), as well

as southeastern Washington (Buchanan 1996).

Buchanan noted that the spotted owls nested in

relatively young (<100 years old) stands, many

of which had a logging history. Buchanan’s work

yielded a total basal area of 236 square feet per

acre with distributions in diameter classes as follows: one percent in the <4” dbh class, 23 percent

in the 4-13” class, 28 percent in the 14-23” class,

40 percent in the 24-33” class, five percent in the

34-43” class, and two percent in the 44-53” class.

Everett et al. (1997) evaluated 48 nest stands,

which had previously been reviewed by Buchanan

(1996), though Everett focused only on reproductive nest sites. Seventy-nine percent of Everett’s

stands were in a grand fir series, whereas 86 percent of the stands were in the SE or UR stage of

development. Everett reported that based on basal

area (188-260 square feet per acre) or crown cover

(83-94 percent), stands with active nesting were

not discernible from non-nesting stands. It is possible that because of territoriality or food limitation,

other stands though suitable could not be used at

the same time as the successful stand. Everett

reaffirmed that vertical diversity was an important

aspect of spotted owl habitat quality. Everett’s work

yielded a total basal area of 236 square feet per

acre, with distributions in diameter classes as follows: eight percent in the <4” dbh class, 27 percent

in the 4-13” class, 14 percent in the 14-23” class,

and 51 percent in the 24” and greater class.
15

Measures of forest structure at known spotted owl

use sites in the Gotchen LSR yielded a total basal

area (square feet per acre) range of 152-383 with

an average of 260 (n=11, SE=23). Basal area was

distributed across dbh classes as follows: 1-2 percent in the <4” dbh class, 23-30 percent in the 4-

13” class, 38-44 percent in the 14-23” class, 17-22

percent in the 24-33” class, 5-9 percent in the 34-

43” class, and 3-7 percent in the >43” class.

Discussion

Existing studies of spotted owl habitat use at nest

sites on the east side of the Pacific Crest are observational rather than experimental. My work in

the Gotchen LSR is also observational but includes

habitat conditions in foraging areas. I used my findings of habitat use by spotted owl to establish a

testable hypothesis, herein presented, on active

management of spotted owl habitat. Spotted owl

habitat definitions have stemmed from interpretation of nest site focused study.

My assumption is that emergent values, such as

spotted owl habitat, are substantially influenced by,

if not a direct result of, forest structure (fig. 5). It is

furthermore assumed that spotted owl habitat quality can be estimated by measuring forest structure

and that this structure can be actively managed to

purposely affect spotted owl habitat quality. Of

course, how wildlife perceives its environment versus how we as humans perceive and measure it,

are not necessarily the same. My findings and proposal are from a limited data set and intended for

preliminary use in the Gotchen LSR. This proposal

needs to be tested with additional data from other

spotted owl use sites on the east side of the Pacific

crest then experimental field tests to assess selection by spotted owls.

Forest vegetation pattern and structural diversity

on the eastern slope of the Pacific Northwest Cascades have changed during the past century

(Everett et al.1997). Conversely, the area covered

by stands in the young forest multi-story structural

stage has decreased. The amount of old-forest

multi-story stands is about the same, but its distribution is more contiguous than a century ago. The

high stem density, particularly of grand fir, is

closely associated with effective fire prevention and

suppression over the past century. Late sere species such as grand fir, which are thin barked and

more readily killed by fire, were typically “weeded

out” by the periodic ground fires, and the opengrown, essentially single story stands were able to

persist for hundreds of years. Though the specific

amount and distribution remains uncertain, the preEuropean forests were typically more open-grown

and park-like than are today’s stands. Periodic 6-

to 45-year return interval, low intensity ground

fires, maintained those open forest conditions

(USDA FS 1997). Low-intensity ground fires were

used in the Gotchen landscape by Native Americans and European settlers (Mack 2000). These

Figure 5—Hypothesis regarding relationship between habitat, forest structure, and goals.
16

ground fires increased the availability of nutrients

while increasing growing space resulting in vegetation growth, which then served as forage for wild

and domesticated ungulates. Dickinson (2000)

reviewed Government Land Office records on forest conditions encountered in the Gotchen LSR by

land surveyors during the late 1800s to early 1900s

(1885-1917). Surveyor records indicate that during

this period, the area below 3,800 feet in elevation

(the southwestern third and the southern fourth of

the LSR), had a tree density (TPA) of 17-27, with a

basal area of 38-55 square feet per acre. Ponderosa pine, Douglas-fir, and lodgepole pine contributed the majority of the tree coverage reported, and

most of the basal area was due to trees at least 30

inches dbh. The northern and eastern two-thirds of

the LSR are reported to have had a lesser tree

density and basal area per acre: 14-20 TPA, 30-72

square feet per acre. Douglas-fir and ponderosa

pine, less than 28" dbh, accounted for the majority

of the basal area. Though relatively stable, these

pre-European stands were still subject to infrequent

stand-replacing fires.

Habitat use by spotted owls for nesting, roosting,

foraging, and dispersal varies across a landscape

(Thomas et al. 1990, North 1993) and the suitability

of an area for a particular use can be rated from

poor to excellent. Recognizing this gradation in

habitat quality, the GPNF stratified forest vegetation into nesting, foraging, dispersal, and non-habitat for spotted owls. On the GPNF, spotted owl

habitat only includes nesting and foraging quality

stands. Spotted owl habitat quality on the GPNF is

estimated by querying the forest’s vegetation database, GPVEG. Stand-scale variables such as elevation, ecoclass, overstory tree size class, dbh,

canopy cover, crown layer, and major species are

queried to identify spotted owl habitat. Generally,

spotted owl habitat on the GPNF is at or below

5,000 feet in elevation, has a canopy cover of at

least 40 percent, and is of a conifer ecoclass. Nesting quality habitat would have an average dbh of at

least 21" and more than one canopy-story. Foraging quality habitat would have an average dbh of

16–20.9" and a single canopy. On the Mt. Hood

National Forest in northern Oregon, for the purpose

of “first screening” of potential late-successional

forest as habitat for spotted owls, Huff et al. (2001)

included forest patches of at least 40 acres below

5,000’ in elevation, with >60 percent canopy closure, and with trees >21” dbh or a mix of trees >21

and 8-21” dbh. Neither the accuracy nor precision

of Huff’s methodology was reported, however.

The actual limits of home ranges for the spotted

owls in the Gotchen LSR are unknown. For the

purpose of habitat analysis and estimating landscape carrying capacity, a circle is used to approximate the home range. Successful spotted owls

have a combination of nesting and foraging quality

habitat in their home range. To be reproductively

successful, spotted owl energy expenditures for

resource gathering must be greater than expenditures. Total acres of spotted owl habitat within a

home range are used on the GPNF as a gauge of

likely success. On the GPNF, minimum spotted owl

habitat thresholds are 2,663 acres and 500 acres

at a 1.82 mile and 0.7 mile radius from the nest

tree. The Gotchen LSR has numerous previously

harvested stands and these stands are within the

home range of at least one spotted owl pair. The

use of partially harvested forest stands by spotted

owls has been observed by the author and has

been described by others including Everett et al.

(1997).

Stand structure reports for spotted owl habitat on

the east side of the Pacific Northwest Cascades

crest have focused on structural conditions at nesting quality sites and or stands. This report addresses foraging quality habitat. A recommended

starting point for teams challenged with managing

for spotted owl habitat in the grand fir zone such as

that in the Gotchen LSR, is a residual basal area of

at least 150 square feet per acre distributed in diameter classes as shown in figure 6. Post-treatment conditions should fit the post-treatment stand

and are expected to (1) fit the “Small Tree - Single

Story - Moderate” forest structural stage, spotted

owl foraging habitat (O’Neil et al. 2001), (2) have a

higher likelihood of stand recovery to late successional condition, (3) have a lower likelihood of

crown (Oliver et al.1994), and (4) have a lower

spruce budworm risk.
17

In the Gotchen LSR, “Declining Stands” should be

the primary focus for application of this thinning

from below guideline. Early sere species should be

favored for retention. Suppressed, understory, intermediate, and co-dominant trees most susceptible to spruce budworm defoliation and root

disease would be preferentially selected for removal. Pre- and post-treatment stand structure

conditions, using current stand structure data, are

depicted in figure 7. The following changes occur:

(1) basal area (square feet per acre) decreases

from 192 to 150; (2) canopy cover decreases from

88 percent to 68 percent; (3) TPA decreases from

about 800 to 70; (4) quadratic mean diameter

(inches) increases from 6 to 19; (5) stand density

index decreases from 415 to 209; and (6) Curtis

relative density decreases from 75 to 35. For this

stand, about 3.5M MBF per acre were removed,

leaving about 14M MBF per acre. Recent timber

harvest (East Timber Sale) in the planning area

indicated a stump-to-truck cost of about $150 per

MBF and a timber value of about $200 per MBF.

Existing tree condition, small diameter, and current

poor market conditions indicate that on this stand

costs would likely exceed revenue.

Figure 6—Proportional distribution

of total basal area in 10" diameter

classes. Foraging quality spotted

owl habitat of the Gotchen LSR.

Figure 7—“Declining Stand” conditions pre and post treatment. Orange tinted trees represent stressed (via pathogens, drought etc.)

trees.
18

Current forest conditions in the Gotchen LSR are

(1) more suitable as spotted owl habitat, (2) more

suitable for forest pathogens, (3) more conducive

to drought related tree mortality, and (4) more susceptible to crown fires. The maintenance of spotted

owl habitat in the Gotchen LSR may be better assured with active silvicultural management. Agee

and Edmunds (1992) recommended active management that affords longer term protection of habitat instead of short-sighted attempts for total

protection that would have been a viable strategy

in 1910 but not today. The immediate need in the

Gotchen LSR is for habitat areas that are on a trajectory towards function loss.

Acknowledgments

I wish to thank my wife and best friend, Nancy C.

Mendez-Treneman. Her patience, encouragement,

and confidence made accomplishment of this

project possible and enjoyable. I thank Dr. C. Oliver

and James McCarter of the University of Washington for their professional, technical, and personal

generosity. Their assistance established an effective framework for investigating, understanding,

and managing natural resource management issues. For their foresight and spotted owl field research in the Gotchen LSR, I thank Dr. L. Irwin and

Tracy Fleming of the National Council for Air and

Stream Improvement, Inc. When it comes to northern spotted owl field biology, Tracy is “The Man.” A

special note of humble appreciation goes to the

reviewers of my drafts. Tremendous gains resulted

from the patient and detailed sharing of your professional knowledge. I thank my co-workers and

managers of the Mt. Adams Ranger District for their

contributions. Mandy Muller’s knowledge and skill

in spatial data are superb. The Stand Exam masters of the LSR include Shildes Kellum, David

Tilton, Christine Bluestone, and Charlene Schmidt.

Attention to detail and procedure in your fieldwork

generates consistently reliable data. Thank you,

Robert Obedzinski and Dr. S. Hummel, for your

charitable guidance and advice. Each person’s

success reflects the support of countless individuals. My wish and intent is to continue this chain of

support.

References

Agee, J.K.; Edmunds, R.L. 1992. Forest protection guidelines for the northern spotted owl.

In: Recovery plan for the northern spotted owlfinal draft. Washington, DC: U.S. Department

of the Interior, U.S. Government Printing Office.

2:181-244.

Buchanan, J.B. 1991. Spotted owl nest site characteristics in mixed conifer forests of the eastern

Cascade Mountains, Washington. Seattle, WA:

University of Washington. 140 p. M.S. thesis.

Buchanan, J.B. 1996. Characteristics of spotted

owl nests and nest sites in Klickitat County,

Washington. [Place of publication unknown]:

[Publisher unknown]; final report. Submitted

to National Council of the paper Industry for

Air and Stream Improvement.

Chappell, C.B.; Crawford, R.C.; Barrett, C. [and

others]. 2001. Wildlife habitats: descriptions,

status, trends, and system dynamics. In:

Johnson, D.H.; O’Neil, T.A., eds. Wildlifehabitat relationships in Oregon and Washington.

Corvallis, OR: Oregon State University Press:

22-114.

Cox, G. 2001. Personal communication. District

Ranger, Mt. Adams Ranger District, Gifford

Pinchot National Forest, 2455 Highway 141,

Trout Lake, WA 98650.

Dickinson, J. 2000. A vegetation reconstruction at

the turn of the 20th century in the Gotchen Late

Successional Reserve in south-central Washington. Unpublished undergraduate senior project.

On file with: College of Forest Resources, University of Washington, Seattle.

Everett, R.; Schellhaas, D.; Spurbeck, D. [and

others]. 1997. Structure of northern spotted owl

nest stands and their historical conditions on the

eastern slope of the Pacific Northwest Cascades, U.S.A. Forest Ecology and Management.

94: 1-14.

Filip, G. 1998. Ecology, identification, and management of forest root diseases in Oregon. EM 8717

[Brochure]. Corvallis, OR: Oregon State University Extension Service.
19

Forsberg, J. 2000. Personal communication.

Silviculturist, Mt. Adams Ranger District, Gifford

Pinchot National Forest, 2455 Highway 141,

Trout Lake, WA 98650.

Gaines, W.L.; Strand, R.A.; Piper, S.D. 1995.

Effects of the hatchery complex fires on northern

spotted owls in the eastern Washington Cascades. In: Greenlee, J.M., ed. Proceedings, first

conference on fire effects on rare and endangered species and habitats. Coeur d’Alene, ID:

International Association of Wildland Fire:123-

129.

Hessburg, P. 2001. Departure analysis. Unpublished report. On file with: Mt. Adams Ranger

District, U.S. Department of Agriculture, Forest

Service, Pacific Northwest Research Station,

Wenatchee Laboratory: Wenatchee, WA.

High, T. 2001. Personal communication. Soil scientist, Gifford Pinchot National Forest, 10600 N.E.

51st Circle, Vancouver, WA 98682

Huff, M.; Mellen, K.; Hagestedt, R. 2001. A model

to assess potential vertebrate habitat at landscape scales: HABSCAPES. In: Quinn, T.;

Johnson, D.H., eds. Wildlife-habitat relationships in Oregon and Washington, five case studies in wildlife modeling. Corvallis, OR: Oregon

State University Press: 544-550.

Mack, C. 2000. Personal communication.

Archaeologist, Mt. Adams Ranger District,

Gifford Pinchot National Forest, 2455 Highway

141, Trout Lake, WA 98650.

North, M. 1993. Stand structure and truffle abundance associate with northern spotted owl habitat. Seattle, WA: University of Washington.

113 p. Ph.D. thesis.

Obedzinski, R. 2001. Personal communication.

Silviculturist, Gifford Pinchot National Forest,

10600 N.E. 51st Circle, Vancouver, WA 98682.

Oliver C.D.; Harrington, C.; Bickford, M. [and

others]. 1994. Maintaining and creating old

growth structural features in previously disturbed

stands typical of the eastern Washington Cascades. Journal of Sustainable Forestry. 2(3/4):

353-387.

Oliver, C.D.; Larson, B.C. 1996. Forest stand

dynamics. John Wiley and Sons, Inc. 157 p.

O’Neil, T.A.; Bettinger, K.A.; Vander Hayden, M.

[and others]. 2001. Structural conditions and

habitat elements of Oregon and Washington In:

Johnson, D.H.; O’Neil, T.A., eds. Wildlife-habitat

relationships in Oregon and Washington.

Corvallis, OR: Oregon State University Press:

115-138.

Thomas, J.W.; Forsman, E.D.; Lint, J.B. [and

others]. 1990. A conservation strategy for the

northern spotted owl, interagency scientific committee to address the conservation of the northern spotted owl. Portland, OR: U.S. Department

of Agriculture, Forest Service, Pacific Northwest

Research Station. 427 p.

Topik, C. 1989. Plant association and management

guide for the grand fir zone. R6-ECOL-TP-006-

88. Vancouver, WA: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region,

Gifford Pinchot National Forest. 110 p.

U.S. Department of Agriculture, Forest Service.

1989. Stand examination program. Field procedures guide. Portland, OR: Pacific Northwest

Region. 61 p.

U.S. Department of Agriculture, Forest Service.

1994. Final supplemental environmental impact

statement on management of habitat for latesuccessional and old-growth forest related species within the range of the northern spotted owl.

Portland, OR: Pacific Northwest Region. 74 p.

U.S. Department of Agriculture, Forest Service.

1997. Forestwide late-successional reserve assessment. Vancouver, WA: Gifford Pinchot National Forest. 242 p.

U.S. Department of Agriculture, Forest Service.

2001. Fuel treatment environmental assessment:

Gotchen Area, Mt. Adams Ranger District. Trout

Lake, WA: Gifford Pinchot National Forest.

30 p.

Willhite, E.A. 1999. Biological evaluation. Western

spruce budworm analysis units. WSCFID 99-1.

Sandy, OR: U.S. Department of Agriculture, Forest Service, Gifford Pinchot and Mt. Hood National Forests. 14 p.
20

Chapter 2

Vegetation
21

Application of Landscape Objectives to Stand-Level

Silviculture: Blue River, Oregon

John H. Cissel, James H. Mayo, Steven L. Garman, and Frederick J. Swanson

Authors

John H. Cissel is a research liaison and James H. Mayo is a silviculturist, U.S. Department of Agriculture,

Forest Service, Willamette National Forest, 211 East 7th Avenue, Eugene, OR 97440; Steve L. Garman is

a terrestrial ecologist, Oregon State University, Forestry Sciences Laboratory, 3200 SW Jefferson Way,

Corvallis, OR 97331; and Frederick J. Swanson is a geologist, U.S. Department of Agriculture, Forest

Service, Pacific Northwest Research Station, Forestry Sciences Laboratory, 3200 SW Jefferson Way,

Corvallis, OR 97331.

Abstract

Managers and scientists associated with the H.J. Andrews Experimental Forest and the Central Cascades

Adaptive Management Area have worked together for the last decade to develop and refine approaches to

landscape management based on interpretations of historical fire regimes. A large-scale effort is now underway in the Blue River watershed (western Cascade Range of Oregon) to implement, monitor and model

this approach, and to apply the lessons learned through adaptive management. A landscape management

plan for the watershed includes guidelines for the frequency, intensity and spatial pattern of timber harvest

that approximate the frequency, severity, and spatial pattern of historical fire in the watershed. These

guidelines provide broad parameters for stand-level prescriptions. Three silvicultural regimes were defined:

a long rotation (260 years) even-aged management approach, a long rotation (180 years) two-aged management approach, and an uneven-aged management approach.

Simulation modeling and field experiments were used to develop stand-level prescriptions. Results from

extensive stand growth modeling using the PNWGAP model, an ecological process-based gap model,

were used to evaluate a wide range of intermediate treatments in terms of late-successional live and dead

wood components and merchantable wood production. Selected prescriptions are in various stages of application to the ground. A network of permanent plots has been established in each of the three silvicultural

regimes to monitor stand growth, mortality, composition, and structure. Nearby young stand field studies

provide additional data concerning the effects of alternative thinning regimes. Practical experience developing and implementing prescriptions for the landscape management plan have resulted in adjustments to

silvicultural prescriptions in an early phase of adaptive management.

Keywords: Late-successional habitat, landscape plan, disturbance regimes, adaptive management, silvicultural regimes, simulation modeling.

Introduction

A team of scientists and managers based on the

H.J. Andrews Experimental Forest and the Blue

River Ranger District of the Willamette National

Forest has been working together for most of this

decade to develop and test a landscape management approach based on natural disturbance regimes (Cissel et al. 1998, Cissel et al. 1999). The

underlying assumption of this approach is that by

approximating key aspects of native disturbance

regimes in management regimes, risks posed to

native species and ecological processes are reduced as compared to other historical and contemporary landscape management approaches

(Swanson et al. 1994, Morgan et al. 1994, Landres

et al. 1999). The Blue River Landscape Study is

intended to use landscape objectives to set broad

direction for stand-level management, and to evaluate the potential effects of implementing a landscape plan based on historical landscape

dynamics.

The 23,900 hectare Blue River watershed study

area is located within the McKenzie River watershed, a tributary of the Willamette River in western
22

Oregon (fig. 1). The Blue River area is part of the

Willamette National Forest and includes the H.J.

Andrews Experimental Forest, a source of extensive ecosystem information. The landscape is

steep, highly dissected, volcanic terrain of the Cascade Range, covered largely by conifer forests

dominated by Douglas-fir (Pseudotsuga menziesii),

western hemlock (Tsuga heterophylla), and Pacific

silver fir (Abies amabalis) of various ages (table 1).

The Northwest Forest Plan sets land-use policy for

portions of the region where spotted owls reside by

defining systems of late-successional reserves

intended to sustain old-growth forest ecosystems

and associated species, riparian reserves, and

stand management prescriptions for matrix lands

between reserves. The study area lies within an

alternative allocation, the Central Cascades Adaptive Management Area, one of 10 adaptive management areas established by the Northwest

Forest Plan. Adaptive management areas are to

test assumptions underlying the plan, and to develop and evaluate new approaches for meeting

Northwest Forest Plan objectives.

Figure 1—Location of the Blue River watershed and Central Cascades Adaptative Management Area.

Table 1— Area of existing stand types

Stand structure Area (acres)

Shrub/sapling (1-20 years) 6,210

Closed pole (21-40 years) 8,550

Young (41-80 years) 2,039

Mature (81-200 years) 15,050

Old (>200 years) 21,130

Nonforest 3,099

Total 56,078
23

Objectives

The landscape management approach used in the

study is intended to meet the same general objectives underlying the Northwest Forest Plan (USDA

FS and USDI 1994): provide habitat to sustain species associated with late-successional forests,

maintain and restore aquatic ecosystems, and provide a sustainable supply of timber. In addition, the

Central Cascades Adaptive Management Area was

directed to develop “approaches for integrating

forest and stream management objectives and on

implications of natural disturbance regimes” (USDA

FS and USDI 1994). The Blue River Landscape

Study incorporates and extends these objectives by

organizing, planning, implementation, effectiveness

monitoring, modeling, and associated research into

an ongoing adaptive management process.

Adaptive Management Model

The adaptive management model followed in this

study consists of three phases. In the first phase,

new information is assessed to determine its potential relevance to the landscape management plan.

Primary sources of new information include operational experience gained through project planning

and implementation, field-based monitoring using

permanent plots and sample points, and modeling

assessments that evaluate the effects of plan

implementation on a variety of species and ecological processes. Research conducted on the H.J.

Andrews Experimental Forest also provides relevant new information through studies designed to

help understand the interactions of landscape patterns and processes. Topics and issues identified

in phase one are then evaluated to determine if

changes should be made to the landscape management plan, or to implementation and monitoring

procedures. Small teams of specialists consider the

implications of new information, develop options for

responding to new information, and make recommendations for change. Options and recommendations are further evaluated through discussions

with interested parties during workshops and field

tours and through feedback obtained directly from

managers, policy-makers, and interest groups

through personal interaction.

In the third phase, revisions to the landscape management plan, or to monitoring and implementation

procedures, are considered if recommendations

from phase two indicate a potential benefit to doing

so. Forest Service managers with input from scientists responsible for conduct of the landscape study

make the final decisions concerning changes to the

study. Changes are documented in updates to the

landscape management plan and in monitoring and

research plans.

Landscape Plan

Fire History

Fire has been a prominent factor shaping landscape structure in the Blue River watershed for

many centuries (Teensma 1987, Morrison and

Swanson 1990, Weisberg 1998). Fire history data

for the watershed were assembled and synthesized

for 407 sample sites representing 44 fire episodes,

and then integrated into a description of three generalized fire regimes representing a complex and

highly varied fire history (Weisberg 1998, Cissel et

al. 1999). Each regime was described by a characteristic fire frequency, fire severity, and mortality

patch size as follows (fig. 2):

1) High Frequency (Mean Fire Return Interval

(MFRI) range of 60-100 years, mean 79 years),

small patches (predominantly <40 hectare), low

severity (40-60 percent mortality).

2) Moderate Frequency (MFRI range of 100-200

years, mean 143 years), moderate sized

patches (predominantly 40-80 hectare),

moderate severity (60-80 percent mortality).

3) Low Frequency (MFRI range of 200-415 years,

mean 231 years), large patches (predominantly

>80 hectare), high severity (>80 percent mortality).

Landscape Management Strategy

The Landscape Plan contains two primary elements: reserves and landscape areas where varying vegetation management regimes are

prescribed. Reserves were identified in two steps,

both prior to and following definition of landscape

areas.

“Special area reserves” were identified first (fig. 3,

table 2). Objectives for these areas were to allow

natural succession to occur. Special area reserves

included late-successional reserves allocated in

the Northwest Forest Plan, the H.J. Andrews Experimental Forest, and three geologically unique

areas allocated as special interest areas in the

Willamette National Forest Plan (USDA 1990).
24

The remainder of the watershed was then subdivided into three noncontiguous zones of distinctive

ecological conditions and disturbance regimes,

termed “landscape areas” (fig. 3, table 2). Landscape area boundaries were based on and closely

followed the interpreted fire regime mapping. Longterm vegetation management prescriptions were

developed for each landscape area based on an

interpreted range of historical conditions. General

prescriptions for timber harvest frequency, intensity,

and spatial pattern (table 3) were derived from corresponding parameters of historical fire regimes.

Timber harvest frequency and rotation age (100 -

260 years) were based upon historical fire frequency, timber harvest intensity (15–50 percent

overstory canopy cover retention) was based upon

historical fire severity, and the spatial patterns of

timber harvest were based upon the spatial patterns of historical fires. Implementation guidelines

are intended to reflect natural disturbance patterns

to the extent feasible while protecting ecological

values.

An aquatic reserve system was also established to

help meet the aquatic ecosystem objectives in the

Northwest Forest Plan. These reserves are of two

types: small-watershed reserves and corridor reserves. Small-watershed reserves are strategically

located throughout the watershed to encompass

areas of particular importance to aquatic ecosystems and spotted owls. In addition, corridor reserves are established on all fish-bearing streams

(fig. 3, table 2). Figure 3 depicts a plan view of the

landscape management plan (“Landscape Plan”),

and, for comparison, a literal implementation of the

standard matrix and riparian reserve system in the

Northwest Forest Plan as if it were applied to the

Blue River watershed (“Interim Plan”).

We next delineated management units, termed

“landscape blocks,” representing the locations of

future patches created through timber harvest,

prescribed fire, and forest regeneration. Landscape

blocks link the landscape plan to site-level project

planning and are the units used to project future

landscape conditions. Existing stand conditions

Figure 2—Generalized fire regimes for the Blue River watershed.
25

Figure 3—Management areas for the Blue River watershed (a) managed under matrix and riparian reserve designations in the Northwest

Forest Plan (termed “Interim Plan”), and (b) for the Blue River landscape management strategy (termed “Landscape Plan”).

Undesignated areas are nonfederal ownership.

Table 2—Area of Landscape Plan management areas. Management

areas are listed in the order of precedence used to calculate area.

 Landscape Plan

Area Area

Management areas (acres) (% of watershed)

Blue River Reservoir 820 1.4

Non-National Forest 2,660 4.5

Special Area Reserves 21,007 35.5

Aquatic Reserves 5,824 9.9

Landscape Area 1 7,469 12.7

Landscape Area 2 9,574 16.2

Landscape Area 3 11,698 19.8

Total 59,052 100.0
26

may be quite variable within a block, ranging from

very young plantations to old growth. Guidance

for the Landscape Plan included specific objectives

for landscape block size (table 3). Existing large

patches and areas of similar landform were included within a block where feasible, and block

boundaries were placed to avoid including entire

watersheds in a single block. Streams, roads,

and ridgelines generally formed block boundaries

(fig. 4).

Evaluation

Future timber harvest and forest age-class structures were projected across the watershed for the

next 200 years for both plans (fig. 5). Results show

that the landscape plan will produce more latesuccessional habitat as compared to the interim

plan (71 percent of the watershed versus 59 percent). Larger patches in the landscape plan create

more interior habitat, thought to benefit some wildlife species such as the northern spotted owl. Relative to the Interim Plan, less edge between old and

young forests in the landscape plan reduces edge

effects such as altered microclimates and increased plant mortality, and may reduce habitat for

certain species that favor edges, such as Rocky

Mountain elk (Cervus elaphus nelsoni). More complex stand structures are present in the landscape

plan due to generally higher overstory canopy

cover retention levels. Retention of live and dead

trees in young stands has been found to favor

cyanolichens, certain fungi and invertebrates associated with older forests, amphibians with life histories requiring both stream/riparian and upland

habitats, and to moderate understory environments. More late-successional habitat and more

large-tree residual structure in young stands in the

Landscape Plan may deliver more large wood and

coarse sediment to streams when mass slope

movements occur, mitigate potential harvest-induced changes to streamflows, and result in more

carbon stored on the landscape. The Landscape

Plan also maintains a substantial component of

the mature forest age class (80-200 years old),

whereas the interim plan nearly eliminates this age

class over time. The absence of mature forest in

the interim plan leaves few options for the future

when mortality due to disturbance, climate change

or senescence eliminates older Douglas-firs in

reserves (Cissel et al. 1999).

Stand-Level Prescriptions

The landscape plan provides general guidance in

terms of the rate, intensity and spatial pattern of

timber harvest for each of the three landscape areas (table 3). These broad parameters shape the

silvicultural system and prescription selected for

each of the landscape blocks where vegetation

management activities are planned and implemented. Stand modeling was used to further develop and evaluate prescriptions, including

potential intermediate entries.

Model Description

We used the PNWGAP model to simulate thinningtreatment effects on stand dynamics (Urban 1993).

PNWGAP simulates the annual establishment,

diameter growth, and mortality of individual tree

and shrub species, and the decay of snags and

logs on a grid of small (0.1 acre) model plots. Diameter growth of individual stems is based on species’ maximum potential rates, which are reduced

as light conditions, soil moisture and fertility, and

ambient temperature deviate from optimum levels.

Light conditions on a model plot are determined by

the leaf area of resident stems and the stature and

leaf area of stems on surrounding model plots.

Stochastic methods are used to simulate annual

weather conditions by using means and standard

deviations of monthly temperature and precipitation. Mortality is modeled as a probabilistic function

of maximum age and number of years of suppressed growth due to resource limitations (i.e.,

shading, drought). When a tree succumbs to mortality, it has a probability of falling or remaining

upright as a snag. Over time, each log and snag

is advanced through the standard decay classes

(Cline et al. 1980) using a probability function

based on maximum residence time, which varies

by decay resistance and stem size (Graham 1982).

Natural inseeding of tree species on a model plot

is determined by the density of sexually mature

stems in a stand and plot-level attributes such as

available growing space, light conditions, and soil

moisture.

Analysis

Simulations representing a wide range of potential

thinning densities were replicated eight times to

derive an average trajectory of stand dynamics and

to evaluate the effects on late-successional attributes and merchantable wood volume production
27

Table 3—Landscape area prescription elements

Prescription elements Landscape Area 1 Landscape Area 2 Landscape Area 3

Rotation age (year/percent

regeneration harvested

annually) 100/1.0 180/0.56 260/0.38

Landscape block sizes

(percent of area)

<1000 acres 60 40 20

100-200 acres 20 40 40

200-400 acres 20 20 40

Retention level (percent

overstory crown closure) 50 30 15

Figure 4—Landscape blocks for the Blue River Landscape Plan.
28

(Garman et al., in press). Treatments evaluated by

the model were selected to bracket a reasonable

range of thinning options. Four thinning densities

at ages 40, 60, and 80 years were evaluated for a

total of 64 possible combinations. For each entry,

a thinning density typical of prescriptions applied in

this area over the last 10 years was selected, then

densities with 50 percent fewer trees, 50 percent

more trees, and a no-thinning treatment were defined (table 4). The first commercial thin was a thinfrom-below approach; the other two entries thinned

proportional to diameter for trees between 4 and 24

inches diameter at breast height (dbh). Each treatment combination was run for two rotations starting

with a 40-year-old stand, for each of the three landscape areas.

Evaluation

Three general criteria were used to evaluate the

simulated prescriptions: (1) time interval required to

develop late-successional characteristics; (2) total

Figure 5—Projected future landscape structures for the Blue River landscape management strategy (termed “Landscape Plan”) and

for the Blue River watershed managed under matrix and riparian reserve designations in the Northwest Forest Plan (termed “Interim

Plan”). Undesignated areas are nonfederal ownerships.

wood volume production; and (3) risks associated

with implementation.

Late-successional conditions of a simulated stand

were evaluated on the basis of threshold values of

characteristic attributes. Threshold levels for large

live trees, shade-tolerant trees, and large snags

and logs were from recommendations by Franklin

and Spies (1991) and the USDA Forest Service

Region 6 Interim Old-Growth Definitions for the

western hemlock series, site class 3 (USDA FS

1993). Vertical heterogeneity is an important characteristic of late-successional stands, but exact

methods for measuring this attribute are lacking in

federal guidelines. As a measure of multi-layer

condition, the Canopy Height Diversity Index

(CHDI) developed by Spies and Cohen (1992) was

used. This index considers the relative volume of

space occupied by tree crowns in five different 50-

foot height classes and has been shown to be sensitive to vertical development in natural Douglas-fir

stands ranging in age from 30 to 999 years. The
29

CHDI criterion of 8.0 corresponds to conditions of

200-year-old, naturally regenerated Douglas-fir

stands.

Species, age, and dbh of harvested stems were

recorded, and total extracted merchantable volume

was derived by using a modified version of the

Harvest model (Harmon et al. 1996). The Harvest

model calculated merchantable volume based on

timber utilization standards, species-specific rot

tendencies, and breakage rates during harvest.

Current harvest standards of a 7-inch minimum

dbh, a 4-inch top, and a stump height of 18 inches

were used in calculating total merchantable volume. Volume production was evaluated for feasibility at each of the intermediate entries as well as the

final harvest. A minimum volume considered to be

economically viable was 700 cubic feet per acre.

Changing market conditions could affect what is

considered a commercial entry.

Relative risk of windthrow, snow and ice damage,

and loss of Douglas-fir was evaluated for each

prescription. Heavy thins generally have a higher

risk of windthrow than light thins, especially when

the stand is densely stocked. This risk can be mitigated by locating heavy thins on lower slopes and

valley bottoms with less wind exposure. There is a

higher risk of snow and ice damage in dense,

unthinned stands where height/diameter ratios are

approaching 100 or more, especially on higherelevation sites. Relatively heavy canopy retention

levels risk loss of relatively shade-intolerant stems

(e.g. Douglas-fir and western white pine).

Results

Several general trends surfaced from inspection of

simulation results. Within each landscape area

there were significant differences in the rate at

which late-successional characteristics appeared.

We focused on live attributes, since snags and

logs can be created when needed. Prescriptions

with heavier thins tended to accelerate development of late-successional characteristics. In some

cases, CHDI or shade tolerant stems were the limiting factor, and lighter thins or not thinning at some

stand ages proved to be a better management tool.

In some cases, the combination of treatments that

most rapidly attained threshold values of late-successional characteristics resulted in lower levels of

late-successional characteristics in the long term.

Wood volume production tended to be inversely

related to late-successional characteristics. Heavythin prescriptions produced less volume overall

than light-thin or no-thin prescriptions. Light thins

keep the site fully occupied, maximizing cubic volume. Wood quality may be higher with fewer, larger

boles. More extreme prescriptions generally have

higher risks, although risks can be mitigated somewhat by choosing prescriptions that fit the terrain

and overstory conditions.

The prescription for landscape area requires close

attention to understory density due to the relatively

heavy overstory (50 percent canopy cover; Zenner

1995, Rose and Muir 1997). The modeled treatment employing two moderate-density thins at ages

40 and 60 years produced late-successional habitat at 64 years, and 7.4 mcf per acre over the 100

year cutting cycle. Heavier thins delayed achieving

threshold values for CHDI and shade tolerant

stems, while lighter thins are not economically viable. Not thinning at all produced up to 10 percent

more volume, but tended to reduce Douglas-fir

presence and would likely render the stand more

susceptible to snow and ice damage.

The general prescription for landscape area two

has an intermediate retention level (30 percent

canopy cover), allowing the understory to develop

for a longer period of time before high densities

significantly reduce the rate of diameter growth.

The simulated prescription of only one moderate

thin at age 60 produced the best balance among

late-successional attributes, volume production,

and implementation risks. This treatment yields

late-successional habitat at 83 years and about 8.8

mcf per acre over the 180-year rotation length.

Earlier and heavier thins delayed development of

shade tolerant stems and produced less volume,

while lighter thins are not considered economical.

Not thinning until age 80, while producing about six

percent more volume, would risk significant snow

Table 4—Simulated thinning densities

Stand Age Thinning Intensity

TPA remaining)

40 all, 165, 110, 55

60 all, 120, 80, 40

80 all, 75, 50, 25
30

and ice damage. Overstory trees help mitigate the

risk of blowdown when the understory is thinned.

Landscape area three has the longest rotation

length (260 years) and the lightest retention level

(15 percent canopy cover). Two moderate thins at

ages 40 and 60 years, followed by a heavy thin at

age 80 produced late-successional habitat in about

150 years with a total volume of 12.7 mcf per acre

over the 260-year rotation. Heavier thins accelerated development of late-successional habitat, but

produced about 10 percent less volume and a

higher risk of blowdown. Lighter thins were not

economical, and not thinning, while producing

slightly more volume (four percent) has a higher

risk of snow and ice damage.

Monitoring

Permanent plots have been installed in each of

the landscape areas to monitor the effects of these

prescriptions on vegetation in both upslope and

riparian environments. Pre-treatment measurements have been taken, and post-treatment measurements are scheduled following planned and

ongoing harvest, prescribed fire, and reforestation

activities. Plot measurements include species and

abundance for all tree, shrub and herb species,

tree diameter, crown closure, crown width, sapwood and bark thickness, tree height, snags,

coarse woody debris, and environmental variables

(slope, aspect, topographic position, and surface

characteristics). Results from monitoring will be

evaluated on a regular basis to determine if there

is a need to adjust plans or practices.

Conclusions

Landscape structures resulting from both the landscape management plan in this study and from the

interim plan are historically unprecedented. For

that reason we feel it is critical that an adaptive

management approach be followed for both plans.

Novel aspects of the Landscape Plan include the

extensive use of information on historical landscape dynamics, use of landscape objectives to

direct stand-level silviculture, and the use of very

long rotations and multi-cohort prescriptions on

federal lands in this forest type. The PNWGAP

model allowed further analysis of stand dynamics

and intermediate treatment options for long-rotation

and multi-cohort prescriptions. We are pressing

ahead with implementation, monitoring, modeling,

and research to better define and evaluate this

approach. We hope these concepts can be tested

in other provinces in the region and that the matrix

and riparian reserve approach of the interim plan

can also be similarly tested.

Acknowledgments

We thank the many people who contributed time

and ideas to the Blue River Landscape Study, and

especially Tere Turner for her production of highquality GIS analyses and products.

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for ecosystem management. In: Jensen, M.E.;

Bourgeron, P.S., eds. Eastside forest ecosystem

health assessment—Volume II: ecosystem management: principles and applications. Gen.Tech.

Rep. PNW-GTR-318. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific

Northwest Research Station: 89-106.

Teensma, P.D.A. 1987. Fire history and fire regimes of the central western Cascades of

Oregon. Eugene, OR: University of Oregon.

188 p. Ph.D. dissertation.

Urban, D.L. 1993. A user’s guide to ZELIG version

2. Fort Collins, CO: Department of Forest Sciences, Colorado State University. 77 p.

U.S. Department of Agriculture, Forest Service.

1990. Land and resource management plan,

Willamette National Forest. Portland, OR:

Pacific Northwest Region. 382 p. [plus

Appendices, 139 p.].

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1993. Region 6: Interim old growth definition.

Portland, OR: Pacific Northwest Region.

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U.S. Department of the Interior, Bureau of

Land Management. 1994. Record of decision

for amendments for Forest Service and Bureau

of Land Management planning documents within

the range of the northern spotted owl. U.S. Government Printing Office, Region 10. 74 p. [plus

Attachment A: standards and guidelines].

Weisberg, P.J. 1998. Fire history, fire regimes,

and development of forest structure in the

central western Oregon Cascades. Corvallis,

OR: Oregon State University. 256 p. Ph.D.

dissertation.

Zenner, E.K. 1995. Effects of residual trees on

growth of young to mature Douglas-fir and western hemlock in the western Central Oregon Cascades. Corvallis, OR: Oregon State University.

Unpublished M.S. thesis.
32

Historical Stand Reconstruction in Ponderosa Pine Forests to

Guide Silvicultural Prescription

Richy J. Harrod, Bradner H. McRae, and William Hartl

Authors

Richy J. Harrod is a fire ecologist, Okanogan-Wenatchee National Forests, 215 Melody Lane,

Wenatchee, WA 98801; Bradner H. McRae is a Ph.D. graduate student, Northern Arizona University,

School of Forestry, Flagstaff AZ 86011-5018; and William Hartl is a silviculturist, Okanogan-Wenatchee

National Forests, Leavenworth-Lake Wenatchee Ranger Districts, 600 Sherbourne, Leavenworth, WA

98826.

Abstract

We reconstructed the historical stand structure and spatial patterning of fire-maintained ponderosa pine

forests in the eastern Cascades of Washington to develop and design silvicultural prescriptions to restore

historical structure and composition. The structure of the dominant overstory was inferred from the size

and spatial patterning of stumps, logs, snags, and live trees (>140 years of age) within 48 0.5-hectare

plots. Size class distributions, basal area, and spatial distribution of historical trees were compared among

plant association groups representing a range of environmental conditions. Using spatial point pattern

analysis, we found significant clumping at the small scale (0-15 meters) existed historically. Spatial patterning of present day and historical trees of four comparable plots suggests that while strong clumping

exists in present day stands, the largest trees today exhibit less clumping than did large historical trees.

Historical stand density index (260) for dominant overstories was nearly the same as threshold for serious

beetle mortality (263) for ponderosa pine. Cut-tree marking was carried out within 15-meter-radius circles,

as guided by the spatial patterning analysis and using a sliding scale of trees per circle by quadratic mean

diameter.

Keywords: Stand reconstruction, ponderosa pine, forest restoration, ecosystem management.
33

Restoring the Longleaf Pine Ecosystem: The Role of Fire

James P. Barnett

Author

James P. Barnett is a chief silviculturist, Southern Research Station, 2500 Shreveport Highway,

Pineville, LA 71360.

Abstract

Longleaf pine (Pinus palustris Mill.) ecosystems once occupied 90 million acres in the southern United

States coastal plain. These fire-dependent ecosystems dominated a wide range of coastal plain sites, including dry uplands and low, wet flatlands. Today, less than 4 million acres remain, but these ecosystems

represent significant components of the region’s cultural heritage, ecological diversity, timber resources,

and present essential habitat for many animal and plant communities. This ecosystem is also the favorite

habitat for endangered species like the red-cockaded woodpecker and the gopher tortoise. Fire was an

essential component of the original longleaf pine ecosystems. The landscapes were characterized by open

stands of mature longleaf pine with a savanna-like understory that was biologically diverse. Recent improvements in the technology to artificially regenerate longleaf pine have stimulated interest in restoring

longleaf pine on many sites. Long-term studies show that the frequent use of fire hastens initiation of

height growth, reduces undesirable competing vegetation, and stimulates growth and development of the

rich understory. Fire is, therefore, an important element in establishing the species and is critical to achieve

and maintain the biologically diverse conditions that are characteristic of the ecosystem.

Keywords: Pinus palustris, regeneration, biological diversity, plantation establishment.

region’s cultural heritage, ecological diversity, timber resources, and present essential habitat for

many animal and plant communities. This once

extensive ecosystem has nearly vanished. The

objectives of this paper are to describe the longleaf

pine ecosystem and its ecological and economic

values and explore possibilities for restoring the

ecosystem to an important part of the southern

landscape.

The Longleaf Pine Ecosystem

The natural range of longleaf pine covers most of

the Atlantic and Gulf Coastal Plains with extensions into the Piedmont and mountains of north

Alabama and northwest Georgia. The species occurs on a wide variety of sites, from wet, poorly

drained flatwoods near the coast to dry, rocky

mountain ridges (Boyer 1990). It is a long-lived

tree, potentially reaching an age of several hundred years; however, longleaf pine forests are

often exposed to catastrophic hazards such as

tropical storms or fire, and to continuing attrition

from lightning, which shortens possible rotation

ages (Landers et al. 1995).

Introduction

Currently, there is considerable discussion about

restoring ecosystems to some previous condition, but there is little consensus on the means

to achieve restoration; what are the target landscapes; what methodologies should be used; and

how is success measured? The present condition

of available sites, the legacies from the past land

use, along with available technology and methods

constrain restoration goals. Restoration of the

longleaf pine (Pinus palustris Mill.) ecosystem in

the southern United States is now receiving a great

deal of attention (Landers et al. 1995, Noss 1989).

The use of fire plays an important role in the restoration of this fire-dependent system.

Longleaf pine ecosystems once occupied over 90

million acres in the southern United States coastal

plain from southern Virginia to central Florida and

west to eastern Texas (Frost 1993). These firedependent ecosystems dominated a wide array of

sites within the region. Today, less than 4 million

acres remain (Kelly and Bechtold 1990), with much

of this in an unhealthy state. Longleaf pine ecosystems represent significant components of the
34

Longleaf pine is a very intolerant pioneer species

and the seedlings go through a stemless grass

stage. If competition is severe, they may remain in

this grass stage for years. The ecosystem is distinguished by open, park-like “pine barrens,” which

are composed of even-aged and multi-aged mosaics of forests, woodlands, and savannas, with a

diverse groundcover dominated by bunch grasses

and usually free of understory hardwoods and

brush (Landers et al. 1995). The diversity of understory plants per unit of area places longleaf pine

ecosystems among the most species-rich plant

communities outside the tropics (Peet and Allard

1993). Although the pine barrens are known for

persistence and diversity, they occur on infertile

soils. The ecological persistence of these areas is

a product of long-term interactions among climate,

fire, and traits of the key plants.

The Historical Role of Fire

Fire was an essential component of the original

longleaf pine ecosystems. Longleaf pine and bunch

grasses (e.g., wiregrass and certain bluestems)

possess traits that facilitate the ignition and spread

of fire during the humid growing seasons (Landers

1991). Frequent fire was largely responsible for the

competitive success of longleaf pine and its associated grasses. These keystone species exhibit pronounced fire tolerance, longevity, and nutrientwater retention that reinforce their dominance and

restrict the scale of vegetation change following

disturbance. Fires that were ignited by Native

Americans or that resulted from thunderstorms with

frequent lightning prevailed over the region, a complex of quick-drying sites that are exposed to natural and anthropogenic disturbances. Many of these

fires occurred during the growing season and

largely prevented species native to other habitats

from encroaching into the pine barrens. The

chronic fire regime also maintained the soil structure and nutrient dynamics to which longleaf pine

is adapted (McKee 1982). These fire effects tended

to make longleaf pine sites more favorable to resident species than those indigenous to more nutrient-rich habitats.

Decline of the Longleaf Pine Ecosystem

The depletion of the longleaf ecosystem resulted

from its many desirable attributes that have caused

it to be exploited since the settlement of the Nation

by Europeans (Croker 1979). However, it was the

event of railroad harvesting in the late 1800s and

early 1900s that provided access to and depleted

the vast remaining longleaf timberland. Cutting

proceeded from the Atlantic states west through the

Gulf Coast Region with increasing intensity of use

with time. Longleaf pine logging reached a peak in

1907, when an estimated 13 billion board feet were

cut (Wahlenberg 1946). The longleaf pine ecosystem now occupies only a small part (less than 5

percent) of its original area. This habitat reduction

is the reason for the precarious state of at least

191 taxa of vascular plants (Hardin and White

1989, Walker 1993) and key wildlife species such

as the red-cockaded woodpecker, gopher tortoise,

and southern fox squirrel (Landers et al. 1995).

Regeneration of longleaf pine was limited because

of a combination of circumstances. The completeness of the harvest left little seed source for natural

regeneration, and much of the harvested land was

cleared for cropland or pasture. Longleaf pine does

not successfully invade open land in competition

with more aggressive pine or grass species. Regeneration sometimes succeeded the removed oldgrowth when periodic fires provided a seedbed and

controlled woody competition and when wild hogs

did not reach a density high enough to destroy

established seedlings (Wahlenberg 1948). The

disruption of natural fire regimes, resulting in part

from forest fire protection policies implemented

during the 1920s, allowed invasion of longleaf sites

by hardwoods and more aggressive pine species.

Longleaf pine and its associated species cannot

compete under these conditions. Regeneration,

both natural and artificial, is more difficult than for

any other southern pine due to the delay in stem

elongation (the grass stage), which is a genetic

trait of the species. Also, survival of planted

bareroot nursery stock is generally poor and established seedlings in the grass stage are very sensitive to competition.

Restoring the Longleaf Pine Ecosystem

A key to restoration of the longleaf pine ecosystem

is to ensure that its recovery benefits society. Without economic benefits, long-term conservation

projects usually do not succeed (Oliver 1992).

Longleaf pine forests have high economic value

due to the quality of solid-wood products produced.

Harvesting or forest management need not be

eliminated or even moderately restricted to restore

and maintain longleaf pine ecosystems, as evidenced by the fact that logging at the turn of the
35

20th century apparently had little effect on groundcover diversity (Noss 1989). Restrictions on harvest would be a disincentive to many landowners

and could result in the elimination of much of the

remaining longleaf pine on private lands.

Restoration of the longleaf pine ecosystem is

achievable since pockets of longleaf pine occur in

much of its former range. It should be feasible to

gradually expand longleaf pine acreage through

education, research, and commitment on the part

of resource managers. Restoration is now a goal

on much of the public lands in the southern United

States, where longleaf pine remains as a component of the forest. In fact, much of the current acreage of the ecosystem occurs on public lands.

A number of interacting factors will determine

whether the restoration of the longleaf pine ecosystem can be achieved. These include the capability

to successfully regenerate longleaf pine on its native sites, to use fire to enhance establishment and

management of both the overstory and understory

species, to educate the public and resource managers on the value and technology of restoration,

and to evaluate restoration success.

Reforestation Technology

Utilization of the trees in the original forest was so

complete that inadequate numbers of seed trees

remained to naturally regenerate many of the harvested stands. Therefore, artificial regeneration

must be used to restore longleaf pine on many of

the appropriate sites where it originally grew. Until

recently, regeneration success from planting was

generally unacceptable due to problems related to

severe competing vegetation, delayed stem elongation, and poor storability of bareroot seedlings.

We now have the knowledge and technology to

reestablish longleaf pine by planting bareroot

stock. The keys to successful establishment are:

well-prepared, competition-free sites; healthy, topquality, fresh planting stock; meticulous care of

stock from lifting to planting; precision planting; and

proper post-planting care (Barnett 1992). Attention

must be given to all of these factors to obtain acceptable seedling establishment, so success of

planting bareroot stock remains elusive.

Planting container stock is now accepted as the

most successful method of regenerating longleaf

pine (Barnett and McGilvray 1997). Production of

longleaf container seedlings has increased from

about 15 million to 85 million annually in the last

five years. This improved survival and growth is

generally attributed to root systems that remain

intact during lifting while roots of bareroot plants

are severely damaged. Thus, container seedlings

experience a significantly shorter period of transplant shock or adjustment than bareroot stock.

However, using container stock does not eliminate

the critical need for controlling competition during

the first growing season after planting.

Role of Fire

Fire is an essential component of the restoration

and management of the longleaf pine ecosystem.

Long-term studies show that the frequent use of

fire hastens initiation of height growth by reducing

undesirable competing vegetation and foliage that

is infected with brown-spot needle blight (Siggers

1934). Longleaf pine seedlings that are in grass

stage are resistant to injury because the buds are

protected by a rosette of needles (Walker and

Wiatt 1966). Prescribed fire also stimulates growth

and development of species that are an essential

component of the understory. Seasonal burning

studies show that late spring burns are much more

effective in the restoration process than the typical

winter burns that are usually favored for other pine

species because they are hotter and more effective

in reducing competing woody vegetation (Grelan

1978). Fire is an important element in establishing

the species and is a critical component for achieving and maintaining the biologically diverse understory that is characteristic of the ecosystem.

Education and Commitment

Educating the public on the current status of the

longleaf pine ecosystem, its potential economic

value, its outstanding biodiversity, and the role of

fire in maintaining the system is an initial step in

securing support for restoration (Landers et al.

1995). A primary need in this process is to promote

the use of fire as an ecological force necessary for

maintenance of this fire-dependent ecosystem.

Frequent prescribed burning, including use of

growing-season fires where appropriate, promotes

the diversity and stability of these communities

(Noss 1989). Many private landowners are concerned about the environment and will support
36

restoration, if through the process they generate

income from their land. Longleaf pine can be managed in an ecologically sensitive manner that generates income satisfactory to interest a landowner

in restoration (Landers et al. 1990).

Determination of Success

One way to measure the success of the restoration

process is to determine through periodic forest

surveys if the area in longleaf pine plantations increases. Another method is to determine if the production of longleaf pine nursery stock increases in

relation to the other southern pines. Some would

question whether an increase in area of longleaf

pine plantations equates to an increase in ecosystem restoration. Certainly it takes more than planting trees to restore the ecosystem, but it is the

critical first step. Recent research indicates that the

productivity of an ecosystem is controlled to an

overwhelming extent by the functional characteristics of the dominant plants (Grime 1997). So, with

reestablishment and appropriate management,

including the appropriate use of fire, restoration

processes that include development of the typical

diverse understory vegetation will begin.

Conclusions

Fire was an important component of the original

longleaf pine ecosystem. Landscapes were characterized by open stands of mature pine with a savanna-like understory. This very biologically rich

understory was typical of the ecosystem. Recent

improvement in reforestation of longleaf pine has

increased interest in restoring the ecosystem on

many sites where it originally grew. It is recognized

that fire must play an important role in the restoration process. Frequent use of fire hastens initiation

of height growth, reduces undesirable competing

vegetation, and stimulates growth and development

of species that are a component of the understory.

Fire is an important element in establishing the

species and is a critical component of achieving

and maintaining the biologically diverse understory

that is characteristic of the ecosystem.

References

Barnett, J.P. 1992. The South’s longleaf pine:

It can rise again! Forests and People. 41(4):

14-17.

Barnett, J.P.; McGilvray, J.M. 1997. Practical

guidelines for producing longleaf pine seedlings in containers. Gen. Tech. Rep. SRS-14.

Asheville, NC: U.S. Department of Agriculture,

Forest Service, Southern Research Station.

28 p.

Boyer, W.D. 1990. Pinus palustris Mill. Longleaf

pine. In: Burns, R.M.; Honkala, B.H. (tech.

coord.). Silvics of North America. Vol. 1, Conifers. Washington, DC: U.S. Department of Agriculture, Forest Service: 405-412.

Croker, W.D. 1979. The longleaf pine story.

Journal of Forest History. 23: 32-43.

Frost, C.C. 1993. Four centuries of changing landscape patterns in the longleaf pine ecosystem.

In: Hermann, S.M., ed. Proceedings, tall timbers

fire ecology conference 18. Tallahassee, FL: Tall

Timbers Research Station: 17-43.

Grelan, H.E. 1978. May burns stimulate growth

of longleaf pine seedlings. Res. Note SO-234.

New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 5 p.

Grime, J.P. 1997. Biodiversity and ecosystem function: the debate deepens. Science. 227(5330):

1260-1261.

Harden, E.D.; White, D.L. 1989. Rare vascular

plant taxa associated with wire-grass (Aristida

stricta) in the southeastern United States. Natural Areas Journal. 9: 234-245.

Kelly, J.F.; Bechtold, W.A. 1990. The longleaf

pine resource. In: Farrar, R.M., Jr., ed. Proceedings, symposium on the management of longleaf

pine. Gen. Tech. Rep. SO-75. New Orleans, LA:

U.S. Department of Agriculture, Forest Service,

Southern Forest Experiment Station: 11-22.

Landers, J.L. 1991. Disturbance influences on

pine traits in the southeastern United States. In:

Hermann, S.M., ed. Proceedings, tall timbers fire

ecology conference 17. Tallahassee, FL: Tall

Timbers Research Station: 61-98.
37

Landers, J.L.; Byrd, N.A.; Komarek, R. 1990. A

holistic approach to managing longleaf pine

communities. In: Farrar, R.M., Jr., ed. Proceedings, symposium on the management of longleaf

pine. Gen. Tech. Rep. SO-75. New Orleans, LA:

U.S. Department of Agriculture, Forest Service,

Southern Forest Experiment Station: 135-167.

Landers, J.L.; van Leer, D.H.; Boyer, W.D. 1995.

The longleaf pine forests of the Southeast: requiem or renaissance? Journal of Forestry. 93:

39-44.

McKee, W.H. 1982. Changes in soil fertility following prescribed burning on Coastal Plains pine

sites. Res. Pap. SE-234. Asheville, NC: U.S.

Department of Agriculture, Forest Service,

Southeastern Forest Experiment Station. 23 p.

Noss, R.F. 1989. Longleaf pine and wiregrass:

Keystone components of an endangered ecosystem. Natural Areas Journal 9: 234-235.

Oliver, C.D. 1992. Achieving and maintaining

biodiversity and economic productivity. Journal

of Forestry. 90: 20-25.

Peet, R.K.; Allard, D.J. 1993. Longleaf pine-dominated vegetation of the southern Atlantic and

eastern Gulf Coast region, USA. In: Hermann,

S.M., ed. Proceedings, tall timbers fire ecology

conference 18. Tallahassee, FL: Tall Timbers

Research Station: 45-81.

Siggers, P.V. 1934. Observations on the influence

of fire on the brown-spot needle blight of

longleaf pine seedlings. Journal of Forestry. 32:

556-562.

Wahlenberg, W.G. 1946. Longleaf pine: its use,

ecology, regeneration, protection, growth, and

management. Washington, DC: Charles Lathrop

Pack Forestry Foundation. 429 p.

Walker, J.L. 1993. Rare vascular plant taxa associated with the longleaf pine ecosystem. In:

Hermann, S.M., ed. Proceedings, tall timbers fire

ecology conference 18. Tallahassee, FL: Tall

Timbers Research Station: 105-125.

Walker, L.C.; Wiatt, H.V., Jr. 1966. Silviculture of

longleaf pine. Bulletin 11. Nacogdoches, TX:

Stephen F. Austin State College, School of Forestry. 105 p.
38

Introduction

The forest landscape in the Pacific Northwest

(PNW) has changed dramatically over the last

century. This is particularly evident in the Douglasfir (Pseudotsuga menziesii (Mirb.) Franco var.

menziesii) region west of the Cascade Divide

where forests have been heavily logged and replaced with young-growth stands, agriculture, or

development. During the last three decades, this

change in forest cover became a national focus

for the efforts of the environmental movement to

preserve old-growth forests and galvanized the

public’s displeasure with clearcutting as the primary harvest method in the west-side PNW forests.

During this same period, several plant and animal

species in the region that are dependent on older

forest structures have been identified as threatened or endangered under the Endangered Species Act of 1973 and the National Forest Management Act of 1976 (USDA FS 1993). These listings,

coupled with legal actions by concerned groups

and the public’s dislike for clearcutting, have forced

reevaluation of forest management strategies and

practices, particularly on public lands. Many alternative silvicultural strategies and practices for managing young-growth forests for multiple objectives

are being proposed and implemented. In many

cases, they are intended to maintain or accelerate

development of forest structural components that

are common to older forests and needed as habitat

for species dependent on older forest types. In

addition, options for harvesting and regenerating

young-growth stands are being implemented with

the intent that they will produce a significant volume of wood products while minimizing visual effect and impact on other values that are often

disturbed by the traditional clearcut system.

Past Research and Management Experience in the Douglas-Fir Region

Past research and management practices in the

Douglas-fir region generally have focused on

clearcutting followed by establishment and management of even-aged plantations. This traditional

approach has emphasized managing one (or a few)

Silvicultural Options for Multipurpose Management of

West-Side Pacific Northwest Forests

Stephen E. Reutebuch, Constance A. Harrington, Dean S. DeBell, David D. Marshall and Robert O. Curtis

Authors

Stephen E. Reutebuch, Constance A. Harrington, and David D. Marshall are research foresters; Dean

S. Debell is a retired research forester; and Robert O. Curtis is an emeritus scientist, Pacific Northwest

Research Station, 3625 93rd Avenue SW, Olympia, WA 98512-9193.

Abstract

The Westside Silvicultural Options Team of the Pacific Northwest Research Station has established an

array of long-term research studies to develop and assess a wide range of silvicultural options. In this paper, we review three large-scale studies that focus on three major stages in the life of managed stands—

early development (precommercial thinning), midrotation (commercial thinning), and regeneration harvest.

These studies will provide information about stand development that will be useful in managing for wood

production, wildlife habitat, and other forest resource values in large portions of the Pacific Northwest westside forests. All three studies measure the response of both overstory trees and understory plant species.

Additionally, several other aspects of concern to forest managers, such as coarse woody debris, residual

stand damage, soil disturbance, economics, and public acceptance of treatments, are investigated.

Keywords: Silviculture, multiple use, silvicultural systems, forest management, precommercial thinning,

variable density thinning.
39

primary tree species in uniform stands. Early management practices were designed to reduce competition from nontimber vegetation and enhance

growth of crop trees. In addition, relatively short

rotation lengths were chosen (in relation to the

biological limits for most northwestern tree species). The intent was to maximize the volume and

value of merchantable wood products with little

attention given to species associated with older

forest structures. Curtis and others (1998) review

the historical development of silvicultural regimes

in the PNW and point out how practices can be

modified and used to maintain and produce wildlife

habitat, diverse stand structures (including those

associated with older forests), and scenic values

while also producing wood products.

There is little research or operational experience,

however, to validate successful outcomes of new

silvicultural approaches being proposed and implemented for managing young-growth stands. These

new approaches generally are intended to mimic

observed characteristics in older stands that developed after natural disturbance. It has been assumed that it is desirable to increase both species

diversity and structural heterogeneity within stands.

No young-growth stands, however, have been managed for an extended period under these proposed

alternative regimes. Thus, estimates of relative

costs and benefits are based on major extrapolations from limited data. In addition, no experimentation has focused on how various factors (i.e.,

understory and overstory species composition,

vertical and horizontal spatial distribution of trees,

snags, and coarse woody debris (CWD) within a

stand, and age-size distribution of trees) independently affect plant and animal populations, or how

altering these factors will impact tree growth, stand

differentiation, habitat functions, or the production

of forest products. Most of the existing work with

alternatives to even-age management in the Douglas-fir region was done in old-growth stands and

has little relevance to management of younggrowth stands (Curtis 1998).

Silvicultural Options Studies in the

West-Side Pacific Northwest Region

The Westside Silvicultural Options Team of the

PNW Research Station is conducting several

large-scale studies of silvicultural options for

young-growth stands. These studies will evaluate

the results of management options intended to

produce multiple resource outputs and habitat values. Three such studies are summarized in this

paper. Each study examines options for managing

young-growth stands in one of three major stages

in the life of managed stands—early development

(precommercial thinning), mid-rotation (commercial

thinning), and regeneration harvest.

Early Development Options—Alternative Silviculture in Young Douglas-fir Plantations

In recent years, the Forest Service in the PNW

region has increased emphasis on young stand

management, including ways to have some stands

develop old-growth structural characteristics. One

study is investigating silvicultural options to create

diverse stand structures by treating young, evenaged plantations. The study area is in the Upper

Clearwater Creek valley of the Mount St. Helens

National Volcanic Monument in the Gifford Pinchot

National Forest. The forests in the area were completely destroyed by the 1980 eruption of Mount St.

Helens. After salvage logging, the area was

planted in the mid-1980s. Young, vigorous, uniform

Douglas-fir plantations resulted from this reforestation effort. Given the timber production goal for

these plantations, the area was scheduled for

precommercial thinning in the mid-1990s as the

plantations approached canopy closure. The

Westside Silvicultural Options Team and the

Gifford Pinchot National Forest staff took this opportunity to design an experiment to investigate

how silvicultural activities, undertaken during the

early development of stands, can influence vegetation structure and thereby habitat.

Study goals—The study goals are to:

1. Test how silviculturally induced variation in tree

species composition and stand structure affect

plant and animal populations.

2. Quantify the effects of different silvicultural

regimes on tree and stand characteristics and

the production of forest products.

Study design—Five treatments were designed

and replicated five times in the study area, resulting in a total of 25 plots. The main aspects of each

treatment are summarized below.
40

A B

Figure 1—Aerial view of uniform (a) and irregular (b) thinning in the Clearwater Valley. The plantation was 12 years old at time of

thinning, the same year these photos were taken.

A. Control plots with no treatments planned for

several decades. Plots were not thinned.

These plots have stands that are uniform with

one primary species (Douglas-fir), a fairly

dense spacing of 680 trees per acre, and

simple stand structure (one canopy layer and

little understory vegetation).

B. Thinning (fig. 1a) to emphasize uniformity of

species composition and stand structure. Plots

were evenly thinned to about half their original

density by removing alternate diagonal rows of

trees. Stand treatments were not intended to

alter species composition. Subsequent commercial thinnings will be applied as stand and

economic conditions allow. In these future

thinnings, the largest, most vigorous Douglasfir, followed by other coniferous species, will be

left. Tree spacing will be kept relatively uniform.

C. Uniform thinning with supplemental plantings in

small, uniform openings to increase tree species diversity. Plots were first evenly thinned as

in treatment B. Immediately after the initial uniform thinning, an additional 100 Douglas-fir

trees per acre were removed to form small,

evenly spaced openings (about 40 by 40 ft). A

mixture of red alder (Alnus rubra Bong.), western hemlock (Tsuga heterophylla (Raf.) Sarg.),

and western redcedar (Thuja plicata Donn ex

D. Don) seedlings were then planted in these

openings. Subsequent commercial thinnings

will be applied as stand and economic conditions allow; however, they will emphasize increasing tree species diversity rather than

maintaining stand uniformity.

D. Irregular thinning with variable-sized openings

to increase structural heterogeneity (fig. 1b).

Plots were thinned to increase horizontal and

vertical diversity (spatial heterogeneity) in the

stand. Plots were first evenly thinned as in

treatment B. Immediately after following the

initial thinning, an additional 100 Douglas-fir

trees per acre were removed in unevenly

spaced clumps that created openings of three

sizes: 30 by 30 ft, 40 by 40 ft, and 50 by 50 ft.

No additional species were planted in these

openings. Subsequent commercial thinnings

will be applied as stand and economic conditions allow; however, increasing heterogeneity

and tree species diversity will be emphasized

by only allowing harvest of Douglas-fir and

expanding or creating new openings in these

thinnings.

E. Irregular thinning with variable-sized openings

and supplemental plantings to increase structural heterogeneity. This treatment is similar to

treatment D; however, openings were planted

with a mixture of red alder, western hemlock,

and western redcedar seedlings. In addition,

30 large, vigorous trees per acre are to be selected for growth enhancement via fertilization.

Twenty of these large trees will be kept in an

open grown condition to maximize growth.

Some of these selected trees will be topped or

killed in several decades to provide early snag

recruitment. The primary objective of subsequent commercial thinnings is to accelerate the

development of multi-layered, uneven-aged,

mixed-species stands.
41

Each treatment plot is 836 by 836 ft (16 acres)

including a 90-ft treatment buffer. Within each plot,

two or three 130- by 200-ft measurement subplots

were located after initial treatments were applied

in 1994 or 1995. In these subplots, all trees were

tagged and measured. In addition, understory and

ground vegetation was surveyed via small area

plots and line transects. Subplots will be periodically remeasured for several decades. Study

response variables emphasize understory development (abundance and diversity of plants), horizontal and vertical vegetation structure, and tree response to thinning (density, spacing, and growth).

Current status—All subplot trees were measured

immediately after initial treatments were applied.

Three years after initial treatment, a subsample

of trees in the subplots was remeasured, then at

5 years, all subplot trees were remeasured. Understory and ground vegetation surveys were conducted 2 and 5 years after initial treatments.

All plots were juxtaposed over a large, highly homogeneous area with regard to climate, aspect,

topography, soil, and current vegetation. This resulted in a high degree of similarity among and

within treatment plots before manipulation, thereby

increasing the probability that real differences

among the treatments will be detected as vegetation develops. In addition, the relatively low density

and limited variety of plant species present in the

area at the time of initial treatments made it relatively easy to manipulate species composition by

planting and seeding. Although no associated wildlife studies have yet been initiated, one might expect that wildlife responses would differ between

treatments as stand structure differentiates over

time.

Midrotation Options—Olympic Habitat Development Study

In the Douglas-fir region, well-stocked stands with

closed canopies often have limited understory vegetation and consequently limited habitat for small

forest-floor mammals. In the absence of active

management (or a natural disturbance), the understories of these stands can remain impoverished

for many decades. However, retrospective studies

have shown that the presence of well-developed

understory and midstory vegetation, cavity trees,

and CWD can allow young, managed stands to

function as late-seral forest for many wildlife communities (Carey and Johnson 1995). In 1994, the

U.S. Congress directed the Forest Service to establish ecosystem restoration demonstrations in

Washington and Oregon. The Westside Silvicultural Options and the Ecological Foundations of

Biodiversity Teams from the Olympia Forestry Sciences Laboratory used this opportunity to collaborate with Olympic National Forest staff to design

and implement the Olympic Habitat Development

Study (OHDS), a large-scale study of silvicultural

management options for midrotation stands on the

Olympic Peninsula.

Study goals—The study goals are to:

1. Test the efficacy of specific management practices for their ability to accelerate development

of stand structures and plant and animal communities associated with late-successional

forests.

2. Test if accelerating the development of structures that are often missing in closed-canopy

midrotation stands will increase the function of

the ecosystem as habitat for terrestrial amphibians and small mammals that dwell on the forest floor.

3. Develop and test in an operational manner

prescriptions that allow wood production consistent with sustainable ecosystems.

Study design—The OHDS was designed as a

randomized block experiment with eight blocks

distributed around the Olympic Peninsula. Each

block has four or five treatment plots that are

15 to 25 acres. Study stands are 30- to 70-year-old

young-growth stands of Douglas-fir, western hemlock, and Sitka spruce (Picea sitchensis (Bong.)

Carr.). The core treatment is a novel variable-density thinning referred to as “thinning with skips and

gaps.” It consists of 10 percent of the area in nocut patches to protect existing snags and portions

of the forest floor, 15 percent in small (65 by 65 ft)

gaps to allow increased light to reach the understory without undermining stand wind resistance,

and 75 percent lightly thinned from below (removal

of 30 percent of the basal area) to increase wind

firmness and to promote understory reinitiation and

development. Minor tree species and trees with

long crowns are retained. In addition to thinning,

CWD treatments are a major feature of the study.

The following five treatments are being applied:
42

Figure 2—Visualization images of a portion (8 acres) of one of the stands in the Olympic Habitat Development Study before (a) and after

(b) application of the variable thinning treatment. Height of snags is exaggerated to increase their visibility. Note that uncut patches were

located to preserve snags.

A. Untreated control.

B. Variable-density thinning with scattered slash

and scattered logs. Additional trees felled to

supplement CWD levels.

C. Variable-density thinning with scattered slash

and clumped logs. Additional trees felled to

supplement CWD levels.

D. Variable-density thinning with slash piled and

logs clumped and supplemental planting of

desired species in gaps. Additional trees felled

to supplement CWD levels.

E. Variable-density thinning with slash left scattered and no supplemental CWD treatment.

The treatments with CWD enhancement (B, C,

and D) were to be evaluated after two winters. If

windthrow and nonmerchantable logs were not

sufficient to meet CWD targets, additional trees

would be felled and left as CWD. The CWD clumping treatments also were to be implemented after

two winters.

Study response variables emphasize CWD function (response of small mammals and amphibians),

understory development (abundance and diversity

of plants, response of small mammals), and tree

response to thinning (density, spacing, and

growth).

Current status—Pretreatment baseline data on

small mammal and amphibian populations were

collected from 1995 through 1998 on all eight

blocks. Pretreatment data describing the presence

and amount of cover of shrubs, ferns, herbs,

mosses, and lichens were collected, as well as

amount of CWD, on all blocks. Tree species, size,

and age data were measured on prism plots in

every treatment plot. One subplot in each block

was stem-mapped (fig. 2). Some blocks also were

used to study forest floor and soil seed banks, understory species root characteristics, and invertebrates associated with CWD.

Thinning treatments are being implemented

through the timber-sale program of the Olympic

National Forest. Four blocks were thinned during

the period 1997-99. The completion date for an

additional block originally scheduled for 2000 has

been extended to 2006. Unfortunately, treatment of

the remaining three blocks has been delayed owing

to the requirement to first complete surveys for

mollusks and fungi on the regional list of species to

be surveyed and managed under the Northwest

Forest Plan (Tuchmann and others 1996).

Post-treatment surveys of wind-thrown trees and

residual stand damage have been completed on

the four thinned blocks. Two blocks have had some

of the CWD treatments and supplemental plantings

implemented after thinning and have had postharvest vegetation surveys.

Carey and Harrington (in press) completed a retrospective analysis of the influence of residual CWD

and vegetation on forest small mammals. The

OHDS is a major part of the adaptive management

area program of the Olympic National Forest.

a b
43

Regeneration Harvest Options—Silvicultural

Options for Harvesting Young-Growth Forests

The wood-producing roles of state, industrial, and

private forests have become increasingly important

as harvests from national forests have declined.

The Washington State Department of Natural Resources (DNR) is one of the largest nonfederal

forest owners in the Northwest and has a legally

defined management objective to generate income

from timberlands in perpetuity for trust beneficiaries

(educational and other state and county institutions). Expanding population, social changes, and

related pressures and conflicts affect the DNR, as

they do other managers of production forests.

Visual effects of harvesting activities are major

considerations in management decisions, especially along major travel routes, in areas with heavy

recreational use, and in the urban-forest interface.

Desire to retain public support and reduce conflicts

have stimulated interest in, and limited application

of, various alternative harvest practices aimed at

reducing visual impacts when young-growth stands

are harvested. Obligations to DNR trust beneficiaries require that forest managers consider financial

trade-offs and effects on long-term forest productivity when implementing alternative harvesting strategies. Unfortunately, little or no management

experience or research exists for these alternative

strategies. The Westside Silvicultural Options

Team collaborated with DNR staff to design and

implement a joint study aimed at evaluating younggrowth harvest practices and silvicultural options

that can be used in a landscape management context to reduce the visual impacts of harvest operations while at the same time maintaining a high

level of timber production.

Study goals—The study goals are to:

1. Evaluate the biological, economic, and visual

effects associated with alternative timber harvest patterns and management regimes for

young-growth forests.

2. Provide experience and demonstrations of

contrasting silvicultural systems that are biologically feasible for management of younggrowth forests in the Douglas-fir region.

Study design—The study is a stand-level experiment that also provides components for various

assessments at the landscape level. It compares

six treatments in a randomized block design with a

planned minimum of three replications. All blocks

are on DNR Capital Forest, a highly productive

young-growth forest southwest of Olympia, Washington. Treatments are being installed as part of

the normal DNR timber sale program and are designed to create highly contrasting stand conditions. They will provide comparative data on

biological responses and economic aspects. They

also will permit evaluation of foreground and landscape-level visual effects. Treatments are applied

in harvest units of 25 to 75 acres each. The initial

treatments are (fig. 3):

A. Clearcut—A conventional even-aged system

widely used in the Northwest and elsewhere.

All merchantable and nonmerchantable trees

will be cut with nearly 100 percent removal.

B. Retained overstory—A two-aged system that

resembles a shelterwood, but with the residual

trees carried through the next rotation to provide some large, high-quality trees. This is a

heavy cut with 15 evenly spaced trees per acre

left as the residual stand.

C. Small patch cutting—An even-aged system in

which small openings (1.5 to 5 acres in size)

are cut over 20 percent of the unit area. A concurrent thinning may be applied throughout the

residual stand for density control purposes.

D. Group selection—An uneven-aged system in

which evenly spaced small openings (up to 1.5

acres in size) are created by removing groups

of trees over 20 percent of the unit area. A

concurrent thinning may be applied throughout

the residual stand for density control purposes.

E. Extended rotation with commercial thinning—

Regular thinning from below in which about 30

percent of the basal area is removed throughout the stand. This treatment takes advantage

of the capacity of thinned Douglas-fir to maintain high growth rates for extended periods. It

defers regeneration harvest, which would eventually be accomplished with any of the above

systems.

F. Unthinned control—No tree removal with regeneration deferred an additional 50 to 75

years.
44

Figure 3—1999 aerial photograph of the Blue Ridge study site showing initial treatment units (yellow).

Regeneration in treatments A-D will be achieved

primarily by planting in openings that are larger

than 0.1 acre, with some supplementary natural

regeneration. No planting is prescribed for treatments E and F. It is planned that plots that initially

receive treatment A will be managed similar to traditional even-aged PNW stands over the next 60

to 75 years, with precommercial and commercial

thinnings conducted as relative stand densities

exceed desired targets. Treatment B plots will be

managed similar to the clearcut plots, except that

the residual overstory (15 trees per acre) will be

retained for several decades. Plots that initially

receive treatments C-E will be retreated (by using

the same guidelines that were used during initial

treatment) approximately every 15 to 20 years

when relative stand densities exceed target ranges.

Permanent, circular, fixed-area plots (0.2 acre)

were installed and measured before treatment.

Plots were located on a regular grid within each

plot. Regeneration and shrub cover were measured

on small, fixed-area plots.

Harvesting production, cost data, log grades, and

volumes will be collected to allow economic comparisons of treatments. Pre- and post-treatment

photographs will be taken within the treatments and

from landscape perspectives, where feasible, to

allow evaluation of visual impacts and public perceptions of each treatment. Such photos will likely

be taken at regular intervals for several decades so

visual changes over time can be evaluated.

Current status—The first block (Blue Ridge) was

harvested in 1998 and replanted in 1999. Pre- and

post-harvest tree and vegetation measurements

have been completed on the first block, as have

measurements for residual stand damage and soil

disturbance levels. Logging production, cost information, and wood products yields were collected.

Pre- and post-harvest photographs of each treatment have been taken and a survey of public preferences of treatments has been conducted by

University of Washington cooperators. The Ecological Foundations of Biodiversity Team has completed a post-treatment survey of song birds.
45

The second block (Copper Ridge) has been designed, pre-harvest plot measurements have been

completed, and the block is scheduled for harvest

in 2002. The third block (Rusty Ridge) has been

identified and is tentatively scheduled for harvest in

2004. In addition to these three replications, the

British Columbia Ministry of Forests plans to install

a replication of the study in British Columbia.

Basic comparisons that will be made between treatments include tree growth and stand development,

public response to visual impacts, harvest operation productivity and economic assessments, levels

of soil disturbance, and song bird usage. The relatively large size of treatment units should provide

opportunities for future research on wildlife and

ecological questions, in addition to the primary

focus on reconciling wood production, economic

returns, and aesthetic values.

Discussion and Conclusions

Although the studies described in this paper address different stand development stages, their

design and implementation have many similarities:

• Studies are in the Douglas-fir region in younggrowth stands.

• Studies are long term and are intended to run

for several decades.

• Multiple forest values and outputs are being

examined.

• Studies involve collaboration with public land

management partners.

• Studies were designed to use adaptive management approaches that allow future treatments to be modified as conditions and

objectives change.

• Study treatments have been implemented as

part of ongoing forest management activities

by the land managers.

• Treatments are intended to stimulate the development of various stand structures.

• Studies were designed with replication and

randomization of treatments.

• Large treatment areas and plot sizes were

implemented, providing sufficient area for

related wildlife research.

• Study sites are valuable as both research and

demonstration sites.

• Undertaking and implementing these studies

required a major effort involving scientists, professionals, and support staff from all involved

partners.

• Studies of this scale usually require supplemental funding from special programs or research

initiatives.

Although direct study of wildlife species is not the

primary goal of these silvicultural studies, each

study is generating valuable information about how

vegetation structure and diversity is modified via

management activities over the life of younggrowth forests in the Douglas-fir region. Such vegetation response data should be of great use to

wildlife biologists as they work to restore or maintain habitat in young-growth forests. When treatment differences in vegetation become established,

these installations will provide outstanding opportunities for direct study of some wildlife species.

The network of studies described in this paper establish an accessible show-case of silvicultural

options that address all phases in the management

of young-growth forests in the Douglas-fir region.

As the forests in these studies develop, they will

provide examples of the environments that can be

created by different management approaches. With

time, the studies also will provide opportunities for

public education and professional training on the

advantages and disadvantages associated with

each silvicultural option.

Acknowledgments

All three of the studies described in this paper

were only possible through the cooperation and

support of many people and organizations. Major

cooperators include Gifford Pinchot National Forest; Olympic National Forests; Washington State

DNR; Olympic Natural Resources Center, University of Washington; University of Idaho; and USDA

Forest Service, Southern Research Station.

The authors thank the many people who have assisted with the development, implementation, and

ongoing monitoring of these studies.
46

Metric Equivalents

1 acre = 0.4047 hectare (ha)

1 foot (ft) = 0.3048 meter (m)

References

Carey, A.B.; Harrington, C.A. [In press]. Small

mammals in young forests: implications for management for sustainability. Forest Ecology and

Management.

Carey, A.B.; Johnson, M.L. 1995. Small mammals

in managed, naturally young, and old-growth

forests. Ecological Applications. (5): 336-352.

Curtis, R.O. 1998. Selective cutting in Douglas-fir.

Journal of Forestry. 96(7): 40-46.

Curtis, R.O.; DeBell, D.S.; Harrington, C.A. [and

others]. 1998. Silviculture for multiple objectives

in the Douglas-fir region. Gen. Tech. Rep. PNWGTR-435. Portland, OR: U.S. Department of

Agriculture, Forest Service, Pacific Northwest

Research Station. 123 p.

Tuchmann, E.T.; Connaughton, K.P; Freedman,

L.E; Moriwaki, C.B. 1996. The Northwest Forest

Plan: a report to the President and Congress.

Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. 253 p.

U.S. Department of Agriculture, Forest Service.

1993. Viability assessments and management

considerations for species associated with latesuccessional and old-growth forests of the Pacific Northwest. Portland, OR. 530 p.
47

Snag Frequencies 50 Years After Partially Cutting Interior

Ponderosa Pine Stands

William W. Oliver

Author

William W. Oliver is a research silviculturist, Pacific Southwest Research Station, 2400 Washington

Avenue, Redding, CA 96001.

Abstract

Snags, or standing dead trees, are important nesting and foraging substrates for many species of wildlife,

especially birds. The importance of this resource to wildlife has prompted forest managers to set snag frequency goals in the forest stands that they manage. Although a body of information links wildlife use to

snags and in some cases minimum snag frequencies, research on the frequencies of snags that should be

expected in late-seral interior ponderosa pine (Pinus ponderosa Dougl. ex Laws.) habitats is scarce. Snag

frequencies were determined in unharvested stands and in stands harvested to varying intensities after 50

years and 43 years after widespread snag felling at the Blacks Mountain Experimental Forest in northeastern California. Recent data show that only unharvested and lightly harvested stands (15 percent of the

merchantable volume removed) met the USDA Forest Service’s recent goal of three snags per acre larger

than 15 inches in diameter. Thus, the capacity of interior ponderosa pine stands to meet this goal is questioned.

Keywords: Ponderosa pine, snag frequency, harvested stands, late seral forests, northeastern California.

insects. And finally, many recently dead trees retain

economic value. Consequently, timber sales generally required removal of all snags in the sale area

and many salvage sales were conducted.

In the 1970s, managers began to realize the importance of snags to wildlife and snag management

became somewhat passive. Although snags no

longer were felled throughout timber sale areas,

neither were they actively recruited. Nevertheless,

snags, especially those of large diameter, continued to decline in number as a result of continued

salvage sales and fuelwood harvest.

In the early 1980s planning regulations promulgated in response to the National Forest Management Act (1976) established minimum management

requirements for snags to enhance diversity of

plant and animal communities. Since then, individual National Forest plans have specified various

snag frequency, condition, location, and species

goals. The Lassen National Forest Land and Resource Management Plan (USDA Forest Service

1993) requires at least:

Introduction

Snags, or standing dead trees, are important nesting and foraging substrates for many species of

wildlife, especially birds. Snags, when they fall,

shelter small mammals and recycle nutrients leading to soil improvement. Dead tops of live trees

also provide foraging and nesting substrates for

some species. The importance of this resource to

wildlife has prompted forest managers to set specific snag frequency goals in the forest stands that

they manage.

Historically, snags were regarded as an undesirable component of managed interior ponderosa

pine (Pinus ponderosa Dougl. ex Laws.) forests.

Before the early 1970s the management objective

was to eliminate snags and dying trees that were

destined to become snags. Snags sometimes constitute a fire hazard because they can serve as

lightning rods, increase the risk of wildfire, and

once ignited, increase its spread by wind-blown

embers. Snags also constitute a human safety hazard because of the risk of falling limbs or boles.

Dying trees serve as reservoirs for tree-damaging
48

• 1.2 snags per acre between 15-24 inches in

diameter at breast height (dbh) and greater

than 20 feet high;

• 0.3 snags per acre greater than 24 inches dbh

and greater than 20 feet high;

• dispersion of one group per 5-15 acres or less

with 5-15+ snags

More snags are required around pileated woodpecker (Drycopus pileatus) nest trees, and green

culls can be substituted for all but one snag per

acre. The recently released Sierra Nevada Forest

Plan Amendment (USDA FS 2001) further requires

snag retention of the largest three snags per acre,

evaluated on a 10-acre basis, when conducting

fuel treatments. However, this study was conducted

on the Blacks Mountain Experimental Forest

(BMEF) that is exempt from these requirements.

How achievable are these standards for the interior

ponderosa pine forest type? The literature on snag

frequencies for late seral stands in northern California has increased (Keen 1929, 1955; Landram

et al. in press; Morrison et al. 1986; Raphael and

Morrison 1987). However, observation periods are

often short and none of the literature relates frequencies to past harvesting practices or to the capability of the forest to support the number of snags

needed to meet guidelines.

I had the opportunity to determine the snag frequencies in unharvested, late seral stands, and in

stands harvested to varying intensities 50 years

ago at the BMEF. This paper discusses a comparison of the snag frequencies at BMEF with snag

size and frequency standards providing insight into

how realistic the standards are for interior ponderosa pine forests.

The Study Area

The BMEF is located 35 miles northwest of

Susanville, Lassen County, California (lat. 40° 40’

N., long. 121°10’ W.) within the interior ponderosa

pine forest type (SAF 237) (Eyre 1980). It is an

extensive forest type that stretches from southern

British Columbia, Canada, to northern Baja California in Mexico and from northeastern California to

the Plains States. In northeastern California, ponderosa pine is the principal species mixed with

small numbers of Jeffrey pine (Pinus jeffreyi Grev.

& Balf.), incense-cedar (Lebocedrus decurrens

Torr.), and white fir (Abies concolor [Gord. &

Glend.] Lindl. ex Hildebr.), becoming prevalent at

higher elevations. Typical of vast areas of this forest type, BMEF has two major age classes that

originated after wild fire exclusion: a scattered

overstory of 300-to 500-year-old pines and a dense

understory of pines and white fir. An intermediate

age class of 150-to 200-year-old trees is largely

absent.

Methods

Between 1938 and 1947 unharvested late-seral

stands were cut to various intensities in a Methodsof-Cutting Study (MOC) (Dolph et al. 1995). Treatments were described by the proportion of

sawtimber volume removed and included—zero

percent (no removal), 15 percent (a sanitation/

salvage cut), 55 percent, 85 percent, and 100 percent removal of the sawtimber overstory greater

than 11.6 inches dbh. Each year for the 10-year

period, treatments were performed on a new group

of four or five 20-acre plots surrounded by a 100-

foot buffer similarly treated. All trees 11.6 inches

dbh within the 20-acre plots were measured for

dbh and tagged before the next growing season

after treatment. Re-measurements were conducted

at 5, 10, and 20 years after treatment. Trees that

had grown to the 11.6-inch minimum size were

measured and tagged at each re-measurement.

In 1947 snags were felled throughout BMEF to

reduce the perceived fire hazard.

In 1990 and 1991, 42 or 43 years after snag removal and 43 to 53 years after partial cutting, all

standing dead trees were tallied on the MOC plots

by plot number, species, and by two dbh classes:

15 to 24 inches and larger than 24 inches. The

total number of acres inventoried for snags by intensity of harvest is shown in table 1.

Because snags were not measured for dbh in the

1990-1991 inventory, ingrowth into the size classes

had to be estimated. The dbh at time of death was

estimated by adding half the growth for that species and size class since the re-measurement

when the tree was last living. Most growth estimates consisted of white fir into the 15- to 24-inch

size class in the 100 percent overstory removal

treatment. The few Jeffrey pine and incense-cedar

snags recorded were combined with ponderosa

pine in this analysis. Snag counts in each MOC

plot were expressed as numbers per acre, and

differences among treatments were analyzed by

one-way Analysis of Variance. Differences between
49

species and size classes across treatments were

analyzed by “t” tests. Also, snag numbers in MOC

plots in almost pure pine stands at lower elevations

were analyzed by “t” test separately from mixed

pine and white fir stands at higher elevations at

BMEF. Significance at the 90 percent probability

level was estimated by the Bonferroni procedure.

Results

In 1990 and 1991, the number of snags in both

ponderosa pine and mixed ponderosa pine and

white fir stands was similar for unharvested stands

and stands with only 15 percent removal (p<0.1).

On a per acre basis, ponderosa pine stands averaged 0.5 small snags, 15 to 24 inches dbh, and 1.7

large snags, larger in dbh than 24 inches (table 2).

Snag frequencies were significantly higher in mixed

stands of ponderosa pine and white fir than in

nearly pure pine stands (p<0.1), averaging 1.1

small snags and 2.8 large snags per acre, due to

higher mortality in small white firs and large pines.

Numbers of snags in all categories generally declined when intensity of harvest increased. At 100

percent removal, there were few snags except in

mixed stands where 2.0 small white fir snags per

acre were recorded.

Discussion

Only the unharvested and lightly harvested stands,

removing 15 percent of the merchantable volume,

produced a sufficient number of snags in the 43

years since the snag felling in 1947. This treatment

met the minimum goal of 1.5 snags per acre required for this area in the Lassen National Forest

Land and Resources Management Plan (USDA

Forest Service 1993) and the updated requirement

of three snags per acre (USDA FS 2001). Stands

harvested more intensively, removing more than 50

percent of the merchantable volume 50 years ago,

produced fewer than 1.5 snags per acre over the

past 43 years.

The requirement of 1.5 snags per acre, and certainly three snags per acre, is unlikely to be met at

present by most managed stands of interior ponderosa pine because the stands and partial harvesting practices at BMEF were common throughout

the region. Until about 10 years ago, a typical cutting practice by the USDA Forest Service (USFS)

was to partially cut stands to 55 percent of the

basal area shown in normal yield tables (Meyer

1938) for the appropriate site quality. The average

stand chosen for cutting had a Site Index of 75

(Meyer 1938) and a stand density of about 80 percent of the normal yield table value or about 140 ft2

per acre of basal area. Because the MOC plots had

a similar Site Index and stand density before treatment, it is likely that extensive areas of the interior

ponderosa pine type fail to meet the USFS snag

frequency goals. Forest inventory data for the interior ponderosa pine type in California provides

evidence of this, showing an average of only 0.6

snags per acre larger in dbh than 20 inches (personal communication, Michael Landram, Regional

Silviculturist, Region 5, USFS).

The failure of the intensively harvested stands at

BMEF to meet snag frequency goals is surprising

because precipitation was below normal for seven

of the eight years before the snag inventory. This

prolonged drought was associated with an abundance of bark beetle-killed trees throughout northeastern California. At BMEF, bark-beetle-induced

mortality has subsequently declined with a return to

normal precipitation levels (personal communication, P. J. Shea, Research Entomologist, Pacific

Southwest Research Station).

Ponderosa pine snags are surprisingly short lived.

In southern Oregon and northeastern California,

only 40 percent of bark-beetle-killed ponderosa

pines were still standing after 10 years and only 25

percent was still standing after 14 years (Keen

1955). In central Oregon, comparative longevities

for fire-killed trees were 47 percent and 35 percent

(Dahms 1949). In Colorado, bark beetle-killed ponderosa pines fell at a faster rate than did Engelmann spruce (Picea engelmannii) (Schmid et al.

1985). A fast rate of fall is probably enhanced by

rapid decomposition of the roots. Ponderosa pine

roots were found to decompose more rapidly than

Table 1—Total number of acres inventoried for

snags by intensity of harvest

Harvest intensity Pine Pine/fir

Percent removal – – – – acres – – – –

0 80 120

15 40 40

55 80 120

85 80 120

100 20 40
50

other common coniferous trees in the Pacific Northwest (Chen et al. 2001). Ponderosa pine snags at

BMEF seem to have similarly short life spans. For

example, the inventories reported here covered

more than 740 acres, and yet only 10 snags predating the previous inventory of 30 years ago were

discovered. Most of these old snags were propped

up by falling into live trees.

Currently, interest is high in creating stands with

age, size, and spatial structures that mimic preEuropean settlement forests. Little or no information exists on historical snag frequencies. The

stands inventoried in this paper are one estimate

of these historical frequencies. Although these data

are the result of only 43 years of snag production, it

could be argued that this estimate may be high

because historical stands were subject to periodic

fire that kept stand frequencies low, eliminating one

major cause of the present mortality of the large old

trees. Because these unharvested and lightly harvested stands, with abundant large old trees, fail to

meet snag frequency standards, the Forest

Service’s current minimum management requirements for snags appear to be higher than interior

ponderosa pine stands managed for timber production can achieve.

Acknowledgments

I wish to thank William F. Laudenslayer, Jr.,

Michael Landram, and two anonymous reviewers

for many valuable comments and suggestions that

strengthened the manuscript. This article is contribution #20 of the Blacks Mountain Ecological Research Project, Pacific Southwest Research

Station, U.S. Department of Agriculture, Forest

Service.

References

Chen, H.; Harmon, M.E.; Griffiths, R.P. 2001.

Decomposition and nitrogen release from decomposing woody roots in coniferous forests of

the Pacific Northwest: a chronosequence approach. Canadian Journal of Forest Research.

31: 246-260.

Dahms, W.G. 1949. How long do ponderosa pine

snags stand? Res. Notes 57. Pacific Northwest

Forest and Range Experiment Station. 3 p.

Dolph, K.L.; Mori, S.R.; Oliver, W.W. 1995. Longterm response of old-growth stands to varying

levels of partial cutting in the eastside pine type.

Western Journal of Applied Forestry. 10(3):

101-108.

Eyre, F.H., ed. 1980. Forest cover types of the

United States and Canada. Washington, DC:

Society of American Foresters. 148 p.

Table 2—Snag frequencies in two species types within interior ponderosa pine forests unharvested

and harvested to remove varying proportions of sawtimber trees 50 years ago at Blacks Mountain

Experimental Forest, California (all snags subsequently felled 43 years ago).

Number of snags per acre by size class and percent timber harvest

15-24 inch dbh size class >24 inch dbh size class

Species 0% 15% 55% 85% 100% 0% 15% 55% 85% 100%

Ponderosa pine stands

Pine 0.6 0.4 0.3 0.1 0.0 1.9 1.5 0.6 0.3 0.0

White fir 0.0 <0.1 <0.1 <0.1 0.0 0.0 0.0 0.0 <0.1 0.0

Both species 0.6 0.4 0.3 0.2 0.0 1.9 1.5 0.6 0.3 0.0

Ponderosa pine-white fir stands

Pine 0.7 0.8 0.2 0.1 0.0 2.2 2.3 0.4 0.3 <0.1

White fir 1.0 1.9 0.7 1.1 2.0 0.4 0.7 0.2 0.2 <0.1

Both species 1.7 2.6 0.9 1.2 2.0 2.6 3.0 0.7 0.4 <0.1
51

Keen, F.P. 1929. How soon do yellow pine snags

fall? Journal of Forestry. 27 (6): 735-737.

Keen, F.P. 1955. The rate of natural falling of

beetle-killed ponderosa pine snags. Journal of

Forestry. 53(10): 720-723.

Landram, F.M.; Laudenslayer, W.F., Jr.; Atzet, T.

[In press]. Demography of snags in eastside

pine forests of California. In: Laudenslayer, W.F.,

Jr., et al., eds. Proceedings of the symposium on

the ecology and management of dead wood in

western forests. Gen Tech. Rep. Albany, CA:

U.S. Department of Agriculture, Forest Service,

Pacific Southwest Research Station.

Meyer, W.H. 1938. Yield of even-aged stands of

ponderosa pine. Tech. Bull. 630. Washington,

DC: U.S. Department of Agriculture. 60 p.

Morrison, M.L.; Dedon, M.F.; Raphael, M.G. [and

others]. 1986. Snag requirements of cavitynesting birds: Are USDA Forest Service guidelines being met? Western Journal of Applied

Forestry. 1(2): 38-40.

Raphael, M.G.; Morrison, M.L. 1987. Decay and

dynamics of snags in the Sierra Nevada. Forest

Science. 33(3): 774-783.

Schmid, J.M.; Mata, S.A.; McCambridge, W.F.

1985. Natural falling of beetle-killed ponderosa

pine. Res. Note RM-454. Fort Collins, CO: U.S.

Department of Agriculture, Forest Service,

Rocky Mountain Forest and Range Experiment

Station. 3 p.

U.S. Department of Agriculture, Forest Service,

1993. Lassen National Forest Land and Resources Management Plan. Susanville, CA:

Lassen National Forest: 4-37.

U.S. Department of Agriculture, Forest Service.

2001. Record of Decision. Sierra Nevada Forest Plan Amendment. Environmental Impact

Statement. Vallejo, CA: U.S. Department of

Agriculture, Forest Service, Pacific Southwest

Region: 4, 10.
52

Damage to Residual Trees from a Commercial Thinning of

Small-Diameter Mixed-Conifer Stands in Northeastern

Washington

Ann E. Camp

Author

Ann E. Camp is lecturer and associate research scientist at the Yale School of Forestry and Environmental

Studies, 370 Prospect Street, New Haven, CT 06511.

Abstract

Dense stands of small-diameter timber are common in the inland West and present unique challenges for

land managers. Managing stands to reduce susceptibility to insects, diseases, and catastrophic fires is

constrained by low economic values of many small-diameter stands and, on public lands, internal and external restrictions on regeneration harvesting. In 1996, the U.S. Congress, recognizing a need to address

forest health issues and stimulate local resource-based economies in northeastern Washington, provided

funds for “implementation and evaluation of controlled silvicultural treatment in designated, fire-generated,

overstocked, small-diameter stands” (U.S. Congress House Report 104-625). As part of this Congressionally mandated research effort, eight harvest units in two different stands were commercially thinned to a

20-foot spacing with different harvesting systems. Comparisons were made among the systems tested to

assess damage to residual trees. While some systems performed better than others, no single system was

clearly superior. Systems producing fewer or less severe wounds were often more costly to implement. In

some cases, wounding may have been exacerbated by factors other than equipment, including the silvicultural prescription and unusual weather conditions during harvest.

Keywords: Silviculture, harvesting, thinning, wounding.

During the 1920s and 1930s, forests in northeastern Washington experienced a series of catastrophic wildfires, many deliberately ignited. In the

aftermath of these fires, dense stands of lodgepole

pine (Pinus contorta var. latifolia), western larch

(Larix occidentalis), Douglas-fir (Pseudotsuga

menziesii), and several other conifer species established. Trees in some lodgepole pine-dominated

stands are now approaching sizes where the initiation and sustained outbreak of mountain pine

beetle (Dendroctonus ponderosae) could occur

(McGregor et al. 1981, Amman and Cole 1983).

Managers express concern that mountain pine

beetle outbreaks could result in widespread mortality of lodgepole pine over large areas, setting the

stage for a repetition of the catastrophic fires that

burned earlier in the century.

Forest health concerns are matched by concerns

about the region’s economic health. Per-capita

incomes in northeastern Washington counties are

some of the lowest in the state. Recognizing an

opportunity for simultaneously addressing forest

Introduction

Forested landscapes characterized by dense

stands of small-diameter trees present considerable challenges to land managers in the Intermountain West. As these stands age they become

increasingly susceptible to insects, pathogens, and

catastrophic wildfires (Oliver and Larson 1996,

Hessburg et al. 1994, Lehmkuhl et al. 1994, Lotan

et al. 1988). With opportunities for harvesting older

stands and larger trees increasingly limited, land

managers are re-thinking management options for

overstocked, small-diameter stands, although

these options are constrained by economics and,

on National Forest lands, public sentiment against

regeneration harvesting. Increasingly, management

opportunities for small-diameter stands will involve

partial harvesting to achieve multiple objectives of

reducing risk of catastrophic disturbances, accelerating stand development trajectories toward latesuccessional conditions for wildlife, and providing

needed jobs and revenues for resource-dependent

rural communities.
53

health issues and stimulating local rural economies, the U.S. Congress (House Report 104-625)

provided National Forest Systems with funding and

legislative language for “implementation and evaluation of controlled silvicultural treatment in designated fire-generated, overstocked, small-diameter”

stands on the Colville National Forest. This research program is frequently referred to by the

acronym CReating OPportunities (CROP).

The first activity included case studies comparing

operational costs of different harvesting systems

used to commercially thin two stands. Four different

harvesting technologies were compared within

each stand. One stand was on a steep slope (>35

percent), the other on more gentle terrain. Treatment effects on residual trees and other stand attributes were measured and are being analyzed

and documented. This paper summarizes each

set of harvesting technologies with respect to the

amount and severity of damage to designated retention trees and to the non-merchantable trees left

on site after harvest.

Methods

Study Site

The case studies were conducted as part of the

Fritz and Fritz Demo I timber sales on the Kettle

Falls Ranger District of the Colville National Forest in Ferry County, WA. Sale units were in the

Sherman Creek drainage, over 50,000 acres of

which burned in the1929 Dollar Fire. A few ponderosa pine (Pinus ponderosa), western larch, and

Douglas-fir survived the fire, providing a source of

seed for regenerating stands. Serotinous cones of

lodgepole pine provided an additional and abundant seed source. Nearly all relic trees died or

were selectively harvested in the first few decades

following the fire.

Two stands, one that established in the aftermath

of the Dollar fire and another that established following a smaller fire that burned a decade or so

earlier, were selected. Four experimental harvesting units were installed in each stand. The steep

stand was on a west-facing slope with aspects between 228 and 300°; average aspect was 256°.

Elevations ranged from 4,440 to 4,700 feet and

slopes were between 23 and 53 percent with an

average slope of 35 percent. Plant associations

within the stand included PICO/SHCA (lodgepole

pine/buffaloberry [Shepherdia canadensis]), PSME/

CARU (Douglas-fir/elk sedge [Calamagrostis

rubescens]), and PSME/VAME (Douglas-fir/big

huckleberry [Vaccinium membranaceum]) as described by Williams et al. (1995). The flat stand

was on gently rolling terrain with predominantly

SE aspects averaging 150°. Elevations ranged

from 3,900 to 4,500 feet; slopes were between 2

and 25 percent, with an average slope of 11 percent. Plant associations included ABLA2/CARU

(subalpine fir (Abies lasiocarpa)/pinegrass

(Calamagrostis rubescens), ABLA2/VAME

(subalpine fir/big huckleberry (Vaccinium

membranaceum), ABLA2/LIBOL (subalpine fir/

twinflower (Linnaea borealis), ABLA2/CLUN (subalpine fir/queencup beadlilly (Clintonia uniflora), and

PSME/VAME (Douglas-fir/big huckleberry). In each

stand, variability of plant associations, trees/acre

(tpa), basal area/acre (ba), and other plot metrics

were as great or greater within units as among

units, reflecting some heterogeneity in initial stand

conditions. Harvest unit size ranged from 8 to 27

acres.

Pre-harvest metrics for each stand are shown in

table 1. Both stands were predominantly a mixture

of lodgepole pine and western larch. Expressed as

tpa lodgepole pine comprised 43 percent of the

steep stand and 45 percent of the flat stand, with

western larch being 34 and 29 percent, respectively. Associated species in the steep stand included Douglas-fir (18 percent), ponderosa pine

(2 percent), and Scoler’s willow (Salix scouleriana)

(2 percent), while in the flat stand, subalpine fir (13

percent), Engelmann spruce (Picea engelmannii)

(7 percent), and Douglas-fir (6 percent) were

included.

The silvicultural prescription consisted of thinning

to a 20-feet spacing between reserve trees, with

the objective of retaining approximately 100 tpa.

Retention trees were clearly marked at diameter at

breast height (dbh) with orange paint. Thinning was

generally from below, removing smaller merchantable trees and favoring retention of western larch,

Douglas-fir, and ponderosa pine. Lodgepole pine

was targeted for removal because of its susceptibility to attack from mountain pine beetles. The spacing constraint and a desire for retaining the

aesthetically-desirable western larch (because of

its fall foliage and visibility from a designated scenic highway) occasionally superceded thinning

from below. Harvest operations in the steep units

began in late July and finished in September 1998.
54

Flat units were harvested during the summer of

1999. Unmerchantable trees were left on site and

not deliberately killed or destroyed.

Harvesting Equipment and Methods

Harvesting systems and the units in which they

were implemented are shown in table 2. Equipment

operation was by professional loggers with experience using the machinery. In the cut-to-length

(CTL) units, a tracked Valmet Model 500T single

grip harvester with tilting cab felled and processed

trees. Forwarding was accomplished with a 1993

Valmet Model 892 with a 14-ton load capacity.

Whole tree felling was done by hand with a chainsaw in one unit and with a tracked Timbco Model

445 B feller-buncher with a 20-inch capacity

Quadco head in the other units. Cable yarding operations incorporated a Skagit Model 333, originally designed as a two-drum yarder, but adapted

with a third drum normally used as a strawline. In

downhill yarding, the strawline was used as the

mainline and the regular mainline was used as the

haulback line. The system included a Christy

haulback carriage with a radio-controlled skyline

clamp. Power was provided to the skyline stop by a

hydraulic accumulator in the carriage. A mobile

tailhold was located on an upper road to provide lift

to the skyline. It was mounted on a crawler tractor

and could travel off haul roads to provide lift. Settings for the downhill yarding were configured with

the haulback line routed over several corridors, up

the hill, and back to the yarding corridor. No intermediate supports were used as all settings had

adequate skyline deflection.

Data Collection

Ten permanent plots were established within each

unit prior to harvesting. Plots were located systematically with random starting points. Plot centers

were marked with a 24-inch rebar stake driven

completely into the soil. An aluminum tag was affixed to the closest tree marked for retention and

engraved with the distance and azimuth to plot

center to facilitate relocating the plots following

harvest. Prior to harvest, > 7 inch dbh were

sampled on 0.1-acre circular plots and all trees > 1

and < 7 inch dbh were sampled on 1/50th-acre plots

nested within the larger plots. The following information was recorded for each tree: species, dbh,

height, height to live crown, crown class, and damage from insects, diseases, or other disturbance

agents. None of the trees in the pre-harvest sample

exhibited wounds that could be mistaken for any

wounding that might occur during harvest.

Following harvest, all remaining trees were

inventoried for harvest-related damage on the

0.1-acre permanent plots and on 10 additional

0.1-acre plots, installed systematically between

permanent plots. Han and Kellogg (2000a)

reported that systematic plot sampling provided

estimates of damage similar to 100-percent surveys. Wound severity was classified by type of

tissue affected. Scraped bark with some cambial

tissue exposed but no penetration into the cambium was considered a minor wound. Penetration

or removal of cambial tissue was considered moderate wounding. Penetration through the cambial

tissue and into the sapwood was considered severe wounding.

Table 1—Pre-harvest stand conditions

Steep Flat

Trees/acre (TPA) 589 1,022

Quadratic mean diameter in inches (Qmd) 6.6 5.7

Basal area in ft2 / ac (BA) 140 180

Percent species composition BA TPA BA TPA

Lodgepole pine (LP) 43 47 42 45

Western larch (WL) 34 34 42 29

Douglas-fir (DF) 18 17 4 6

Ponderosa pine (PP) 2 2 — —

Subalpine fir (SF) — — 8 13

Englemann spruce (ES) — — 4 7
55

Results

Damage to Trees Specifically Marked for

Retention

Following harvest, density of designated retention

trees in the eight experimental units varied from 66

to 99 tpa (table 3). Lower residual amounts than

the 100 tpa specified in the prescription reflect the

relatively small size of the harvest units and some

necessary removal of retention trees to accommodate skyline corridors and forwarder trails. In addition to designated retention trees, between 71 and

638 unmerchantable trees/acre were left on the

site.

Mean percentages of designated retention trees by

wound severity are shown in tables 4 and 5. In the

steep stand, the least moderate-to-severe wounding occurred with the CTL and downhill skyline

system. The CTL and forwarder system had the

greatest combined cambial and sapwood damage,

although this system resulted in the greatest percentage of undamaged trees and was the least

costly system to implement. In the flat stand, the

smallest percentage of moderate-to-severe wounding occurred in the unit in which whole trees were

harvested with the feller-buncher while the greatest

amount of moderate to severe wounding occurred

with the CTL and feller-buncher system.

Discussion

Trees sustain wounds when cambial tissue is exposed through breaks in the bark. Wounds can

result in stain, decay and stem deformity, impacting

stand development and the ability of a stand to

provide commodity and amenity values. From a

timber perspective, wounds reduce future value of

the stand, especially when wounds are large, numerous, and prone to decay (Han et al. 2000b).

Factors predisposing a tree to wounding include

its species and the season when harvesting occurs. Silvicultural prescriptions that are difficult to

implement may also contribute to residual stand

damage.

The silvicultural prescription for these case studies

stipulated that western larch and Douglas-fir be

preferentially retained over lodgepole pine to create stands less at risk to catastrophic fires and

Table 2—Harvesting systems and the units in which they were implemented

Forwarding / Yarding

 Felling and Processing Ground-based Cable

Unit and Trail Corridor

abbreviation Method Equipment Equipment spacing Method width

Feet Feet

Steep stand

8 CTLUS CTL CTL Harvestera 40 Uphill 80

9 CTLF CTL CTL Harvester Forwarderb 40 — —

16 WTFB Whole Tree Feller-buncherc 40 Downhill 40

17 CTLDS CTL CTL Harvester 40 Downhill 80

Flat stand

2 HF Hand CTL Harvester Forwarder 130 — —

3 CTLF CTL CTL Harvester Forwarder 40 — —

4 WTFB Whole Tree Feller-buncher Skidderd 130 — —

19 CTLFB Whole Tree Feller-buncher Forwarder 130 — —

+ CTL

Harvester

aTracked Kabelco 200 single-grip harvester with Kato 500 saw head

b

 Rubber-tired Valemt 892 forwarder (14-ton capacity)

c

 Tracked Timbco 445 feller-buncher with Quadco Hot-Saw felling head

d

 Rubber-tired Caterpillar 518 skidder with swinging grapples
56

Table 3—Post-harvest retention levels of designated and unmerchantable trees

Unit number and abbreviation Designated retention trees/acre Unmerchantable trees/acre

Steep

8 CTLUS 87 244

9 CTLF 66 79

16 WTFB 88 164

17 CTLDS 66 224

Flat

2 HF 80 638

3 CTLF 71 430

4 WTFB 74 525

19 CTLFB 99 313

Table 4—Steep stand wounding expressed as the percentage of designated

retention trees

Minor Moderate Severe

Relative No damage damage damage

Harvest system Cost damage (bark) (cambial) (sapwood)

CTLUS $$ 9 45 23 23

CTLF $ 26 26 27 21

CTLDS $$$ 12 50 24 14

WTDS $$$$ 15 39 17 30

Table 5—Flat stand wounding expressed as the percentage of designated

retention trees

Minor Moderate Severe

Relative No damage damage damage

Harvest system Cost damage (bark) (cambial) (sapwood)

HF $$$$ 17 42 25 16

CTLF $ 10 44 34 12

WTFB $$$ 46 29 14 11

CTLFB $$ 8 40 26 26
57

outbreaks of mountain pine beetle. Unfortunately,

the desired post-treatment conditions were not met

because of the large number of unmerchantable

trees left on site. While some of these trees may

die from windthrow, snow and ice breakage, or

competition with larger trees, others are likely to

persist. Furthermore, some research suggests that

species conversion through silvicultural thinning

could replace one set of forest health problems

with others. Many residual trees sustained wounds

penetrating the cambium and sapwood. In a survey

of mixed stands of lodgepole pine and western

larch, Allen and White (1997) noted that 88 percent

of the larch but only 8 percent of the lodgepole

pine had decay associated with past wounds. Filip

et al. (1995) also reported an absence of decay in

wounded lodgepole pine three years after a commercial thinning operation.

Retaining trees on a 20-foot grid may have constrained equipment. Sizes and species of trees

likely exacerbated wounding levels and compounded problems associated with narrow spacing

of residuals. Many designated retention trees were

small and had thin bark, increasing the likelihood

that wounds would penetrate into cambial or sapwood tissues. In the flat units, the density of very

small trees made it extremely difficult to manually

fell trees and operate equipment. It would have

perhaps been more efficient to retain trees in

clumps interspersed with open areas rather than

attempt to create a uniform spacing between designated retention trees.

Weather probably played a role in the amount of

damage to retained trees in the steep stand. Harvesting began in late July, following an unseasonably long, wet spring. Typical hot dry summer

weather did not occur until the middle of August.

Research comparing production and cost of the

harvesting systems indicated that bark on 33 percent of the harvested trees was so loose as to require two or more passes over a felled tree for the

processor to accurately measure log lengths

(Johnson 1999). This suggested active cambial

growth and higher susceptibility to damage (Wilcox

et al. 1954, Hennessey et al. 1989, Smith et al.

1997).

Conclusion

Because these are unreplicated case studies, it is

difficult to draw firm conclusions regarding the best

system(s) to use to reduce wounding incidence and

severity. Cost of implementation may reduce the

incentive for using a system that reduces the incidence of wounding, especially in stands that are

already marginally economic.

Wounding to residual trees in the experimental

harvest units occurred because of several factors,

only one of which was the harvesting technology

utilized. Overall wounding could probably be reduced with silvicultural prescriptions calling for

wider spacing between residuals and less uniform

distribution of retention trees to mitigate problems

associated with height/diameter ratios. When specific numbers of trees/ac are required, wider spacing could be achieved through some clumping of

residuals rather than leaving all trees in a grid configuration (Smith et al. 1997). More research on

how different silvicultural prescriptions alter wounding metrics and operational costs in dense, smalldiameter stands would be beneficial.

Han and Kellogg (2000) recommend designating

skid trails and skyline corridors prior to marking

leave (crop) trees. Doing so might have resulted

in more closely meeting the objective of retaining

100 crop trees/acre. Management objectives determine acceptable levels of decay in living trees.

Management toward providing late-successional

habitat will be more tolerant of wounds at risk to

decay than management toward providing large

trees for timber. However, management goals generally change more rapidly than the ability of stand

development processes to achieve the conditions

required to fulfill new objectives. Reduction of

wound-induced decay in residual stands might be

achieved through silvicultural prescriptions allowing for more lodgepole pine in the residual stand.

The amount of pine retained may need to be balanced against the risk of creating optimal habitat

for mountain pine beetles.

Season of harvest likely played a role in the damage sustained by residual trees in the steep stand

units. It is likely that had harvesting occurred in late

fall or winter after cambial development ceased,

wounds would have been smaller or less severe. In

particular, it would be of interest to compare size

and severity of wounds incurred with the CTLF

system during different seasons. While this system

did not perform well with respect to percentage of

residual trees sustaining moderate and severe

wounds, it did result in the highest percentage of

residual trees that had no damage whatsoever.
58

Acknowledgments

The author thanks Elizabeth Goulet and Lindsay

Herman for field assistance, Leonard Johnson,

Tom Pawley, Gary Nielsen, and Dave Newton

for technical assistance, and the PNW CReating

OPportunities (CROP) project for financial

assistance.

References

Allen, E.; White, T. 1997. Decay associated

with logging injuries in western larch, Larix

occidentalis, and lodgepole pine, Pinus contorta.

For. Res. App. Tech. Trans. Note 7. Victoria,

British Columbia: Natural Resources Canada.

Pacific Forestry Center. 4 p.

Amman, G.D.; Cole, W.E. 1983. Mountain pine

beetle dynamics in lodgepole pine forests. Part

II: population dynamics. Gen. Tech. Rep. INT145. Ogden, UT: U.S. Department of Agriculture,

Forest Service, Intermountain Research Station.

59 p.

Filip, G.M.; Parks, C.G.; Wickman, B.E. [and

others]. 1995. Tree wound dynamics in thinned

and unthinned stands of grand fir, ponderosa

pine, and lodgepole pine in eastern Oregon.

Northwest Science. 69(4): 276-283.

Han, H-S.; Kellogg, L.D. 2000a. A comparison of

sampling methods for measuring residual stand

damage from commercial thinning. Journal of

Forest Engineering. 11(1): 63-71.

Han, H.-S.; Kellogg, L.D. 2000b. Damage characteristics in young Douglas-fir stands from commercial thinning with four timber harvesting

systems. Western Journal of Applied Forestry.

15(1): 27-33.

Hennessey, M.T.; Ostrofsky, W.B., Lemin, R.C.

1989. Damage to residual trees from a mechanized harvest during winter and summer in a

northern hardwood stand. In: Proceedings, annual meeting of the American Phytopathological

Society. St. Paul, MN: 79: 1220.

Hessburg, P.F.; Mitchell, R.G.; Filip, G.M. 1994.

Historical and current roles of insects and

pathogens in eastern Oregon and Washington

forested landscapes. Gen. Tech. Rep. PNWGTR-327. Portland, OR: U.S. Department of

Agriculture, Forest Service. Pacific Northwest

Research Station. 72 p.

Johnson, L.R. 1999. Combining cut-to-length and

cable yarding operations. In: Proceedings, international mountain logging and 10th Pacific Northwest skyline symposium. Corvallis, OR: Oregon

State University: 43-52.

Lehmkuhl, J.F.; Hessburg, P.F.; Everett, R.L.

[and others.] 1994. Historical and current forest

landscapes of eastern Oregon and Washington.

Part 1: vegetation pattern and insect and disease hazards. Gen. Tech. Rep. PNW-GTR-328.

Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Research Station. 88 p.

Lotan, J.E.; Carlson, C.E.; Chew, J.D. 1988.

Stand density and growth of interior Douglas-fir.

In: Schmidt, W.C., ed. Proceedings, Future forests of the mountain West: a stand culture symposium. Gen. Tech. Rep. INT-243. Ogden, UT:

U.S. Department of Agriculture, Forest Service,

Intermountain Research Station: 185-191.

McGregor, M.D.; Amman, G.D.; Cole, W.E. 1981.

Hazard rating lodgepole pine for susceptibility

to mountain pine beetle infestation. In: Hedden,

R.L.; Barras, S.J.; Coster, J.E., eds. Proceedings, Hazard-rating systems in forest insect

pest management. Gen. Tech. Rep. WO-27.

Washington, DC: U.S. Department of Agriculture, Forest Service: 99-104.

Oliver, C.D.; Larson, B.C. 1996. Forest stand

dynamics. New York: John Wiley and Sons.

520 p.

Smith, D.M.; Larson, B.C.; Kelty, M.J. [and

others]. 1997. The practice of silviculture:

applied forest ecology. New York: John Wiley

and Sons. 537 p.

Wilcox, H.; Czabator, F.; Girolami, G. 1954. Seasonal variations in bark-peeling characteristics

of some Adirondack pulpwood species. Journal

of Forestry. 52(5): 338-342.

Williams, C.K.; Kelley, B.F.; Smith, B.G. [and

others]. 1995. Forested plant associations of

the Colville National Forest. Gen. Tech. Rep.

PNW-GTR-360. Portland, OR: U.S. Department

of Agriculture, Forest Service, Pacific Northwest

Research Station. 375 p.
59

Lake States Aspen Productivity Following Soil Compaction

and Organic Matter Removal

Douglas M. Stone

Author

Douglas M. Stone is a research forester, North Central Research Station, 1831 Highway 169 East,

Grand Rapids, MN 55744.

Abstract

Aspen (Populus tremuloides Michx. and P. grandidentata Michx.) provides wood products, watershed protection, and wildlife habitat for numerous game and non-game species across the northern Great Lakes

region. Sustaining the productivity of these ecosystems requires maintaining soil productivity. Management

activities that decrease soil porosity or remove organic matter can reduce productivity. We determined effects of three levels of soil compaction and organic matter removal (OMR) on aspen regeneration and

growth following winter harvest of aspen-dominated stands in northern Minnesota, western Upper Michigan, and northern lower Michigan. Compaction treatments were applied to increase surface soil bulk density by either zero, 15, or 30 percent. The OMR treatments were merchantable bole harvest (MBH); total

tree harvest (TTH); and total woody vegetation, plus forest floor removal (FFR). Soil compaction tended to

increase mean sucker diameter and height on the sand and decrease them on the fine textured soils. Compaction greatly reduced sucker density and growth on the most productive silt-loam soil, primarily due to

late spring treatment. These results apply to planning of operational harvest of aspen-dominated stands

throughout the northern Great Lakes region. Sucker density increased with level of OMR on all three sites.

On the sand site, mean diameter, height, and biomass were greatest with MBH and decreased significantly

with increasing OMR, indicating a potential decline in productivity with repeated total tree harvesting on

sand soils.

Keywords: Sustaining productivity, harvest intensity, organic matter removal, soil compaction.

The rationale for these studies is: (1) harvesting

equipment and practices affect soil properties;

(2) soil properties control soil processes; (3) soil

processes affect plant community composition

and growth; and (4) these determine net primary

production, ecosystem functions, and forest sustainability. The objectives are to monitor changes

in soil properties following forest harvesting and

the soil compaction and OMR treatments, and to

measure responses by the forest regeneration and

herbaceous vegetation. Fifth-year results from a

pilot study with four treatments and two replications

(Stone and Elioff 1998) and 4th-year results of the

complete study with nine treatments and three replications on sand soils were reported earlier (Stone

et al. 1999). This paper summarizes aspen development after five growing seasons on sites in

northern Minnesota, western Upper Michigan, and

northeastern lower Michigan.

Introduction

Sustaining forest productivity requires maintaining

soil productivity. Management activities that decrease soil porosity and/or remove organic matter

have been associated with declines in site productivity (Agren 1986, Greacen and Sands 1980, Grier

et al. 1989, Standish et al. 1988). As part of an

international network of cooperative studies on

long-term soil productivity (LTSP) (Powers et al.

1990, Tiarks et al. 1993), we are evaluating effects

of soil compaction and organic matter removal

(OMR) in the aspen (Populus tremuloides Michx.

and P. grandidentata Michx.) forest type across the

northern Lake States region and in northeastern

British Columbia (Kabzems 1996, Stone and Elioff

1998, Stone et al. 1999). The research is designed

to determine how changes in soil porosity and organic matter content affect soil processes controlling forest productivity and sustainability, and to

compare responses among major forest types and

soil groups across the United States and Canada.
60

Methods

Stand and Site Conditions

Four sites were selected to represent a range of

soil conditions and aspen productivity across the

northern Lake States region (table 1). The overstory of each stand was dominated by aspen but

included a codominant component, or a subcanopy

of more tolerant conifer and northern hardwood

species. The pilot study is on the Marcell Experimental Forest (part of the Chippewa NF), and represents our medium site (Stone and Elioff 1998).

The surface soils are loamy sand over clay loam till

at about 110 cm; site index (age 50) for aspen is

about 21 m (70 ft). The least productive site is on

the Ottawa National Forest (NF) in western Upper

Michigan. The study is on a glacial lake plain and

the soils are moderately well-drained, calcareous,

lacustrine clay; site index for aspen is 17 to 18 m

(55 to 60 ft). White spruce (Picea glauca (Moench)

Voss), balsam fir (Abies balsamea (L.) Mill.), and

red maple made up about 35 percent of the preharvest basal area. The most productive site is on

the Chippewa NF in north-central Minnesota. The

study is located on the Guthrie till plain; the surface

soils are silt loam, formed from a loess cap 30 to

40 cm deep, over clay loam till. Site index is about

23 m (75 ft); the associated species were predominantly red maple (Acer rubrum L.), basswood (Tilia

americana L.), sugar maple (A. saccharum Marsh.),

and eastern white pine (Pinus strobus L.). Our

medium-to-low-quality site is on an outwash plain

on the Huron NF in northeastern lower Michigan;

the soils are deep, acid sands with a site index of

about 19 m (62 ft). Both trembling and bigtooth

aspen occur on this site. The predominant associated species were red maple, red oak, black cherry

(Prunus serotina Ehrh.), and white pine.

Design and Treatment

Three levels of harvest intensity and OMR, and

three levels of soil compaction were applied to

50×50 m (0.25 ha, 0.62 ac) plots in a complete

3×3 factorial design with three replications. The

compaction treatments were designed to provide:

(1) no additional compaction above that due to

harvesting; (2) light, to increase bulk density of the

surface 10 to 20 cm of soil by 15 percent; and (3)

heavy, to increase bulk density of the surface soil

by 30 percent. The levels of OMR were: (1) merchantable bole harvest (MBH) to a 10 cm (4 in.) top

diameter; (2) total aboveground tree harvest (TTH);

and (3) total woody vegetation harvest plus forest

floor removal (FFR). The FFR treatment was included to represent those areas in skid trails and

landings where most, or all of the forest floor materials, are removed during harvest. It also could

provide an indication of productivity trends following repeated rotations of total tree harvesting. Tops

from the MBH+compaction treatments were piled

adjacent to the plots and replaced after the compaction treatments were completed. Four non-cut

control plots were installed in the adjacent stands,

for a total of 10 treatment combinations on each

Table 1—General characteristics of the aspen Long-Term Soil Productivity (LTSP) sites in the

Lake States

Installation National Relative General Soil Approximate

Date Forest Productivity Description Site Indexa

(m) (ft.)

1991 Marcell Medium Loamy sand/clay loam till

at 110 cm; well drained 21 70

1992 Ottawa Low Deep, calcareous clay;

moderately well drained 17-18 55-60

1993 Chippewa High Silt loam cap/clay loam till

at 30 to 40 cm; well drained 23 75

1994 Huron Medium Deep, acid sands;

to low excessively drained 19 62

 aAspen, age 50
61

site. Prior to harvest, the plots were established

to minimize variation in soil properties and all trees

=10 cm (4 in.) diameter at breast height were measured and their location mapped.

Ottawa—The stand was harvested between

January 13 and February 3, 1992. During logging,

snow depths averaged 76 to 91 cm (30 to 36 in.)

and the soils were not frozen. All merchantable

stems were cut by using a Caterpillar model

FB-227 feller-buncher and placed in bunches

between the plots. The bunches were skidded

to a landing with John Deere 648D, 740A, and

Timberjack 450B grapple skidders. All skidder traffic was restricted to the areas between plots. The

FFR treatment consisted of manually removing all

coarse woody material and then removing the forest floor materials between April 21 and May 21 by

prison work crews using fire rakes; the materials

were piled outside of a 5- to 10-m-wide buffer zone

surrounding each treatment plot. The compaction

treatments were applied between May 6 and 21 by

traversing the plots with a 20.9-Mg (23-ton) Hough

model H-100 front-end loader, advancing one tire

width each pass. Two passes at right angles provided the light treatment, and two passes with the

bucket empty and two passes with the bucket filled

with soil provided the heavy compaction.

Chippewa—The stands were harvested during

January and February 1993. During November and

December 1992, snowfall was somewhat greater

than normal and mean monthly air temperatures

were slightly above average. Thus, soil frost was

discontinuous initially, and ranged from 5 to 10 cm

(2 to 4 inches) when logging was completed. Snow

depth increased from about 30 cm (12 in.) initially

to 46 cm (18 in.) during the logging operation. On

the non-compacted plots, the trees were felled with

chainsaws and winched off the plots with a cable

skidder. On all other plots, the stems were cut with

a Case-Drott model 40 feller-buncher and placed

outside the plot boundaries; skidders did not enter

any of the plots. The FFR treatment consisted of

manually removing all coarse woody material and

then windrowing the forest floor materials by using

a power-driven sidewalk sweeper with a revolving

wire brush head; the materials were piled outside

of the 5- to 10-m-wide buffer zone surrounding the

treatment plots. The light compaction treatment

consisted of a double pass, at right angles, across

the plots with a model D-7 Caterpillar tractor, advancing one track width each pass. The heavy

compaction treatment included the light treatment

followed by a double pass with a Michigan model

75C front-end loader, advancing one tire width

each pass.

Huron—The stands were harvested in late January

1994; the winter was colder than normal, with several days below -30°C ( -22°F). During harvest, the

surface 20 to 25 cm (8 to 10 in.) of soil was frozen

and covered by 35 to 40 cm (14 to 16 in.) of snow.

All merchantable stems were cut with a tracked

Bobcat shear or a Hydro-Ax feller-buncher, and

skidded using Caterpillar 518, and Timberjack

380B grapple skidders. In mid-April, the coarse

woody debris and forest floor materials were removed by using the same methods as on the

Chippewa, and piled outside the 5- to 10-m-wide

buffer zone around each treatment plot. In late

April, when the soil was at field capacity, the compaction treatments were applied by using a 9.5-Mg

(10.5-ton) Hough model 60 front-end loader, advancing one tire width each pass. The light compaction treatment was accomplished with a single

pass of the loader with a tire pressure of 172 kPa

(25 psi). The heavy compaction treatment included the light treatment plus a second pass of

the loader, at right angles, with the bucket filled

with sand and tire pressures of 276 kPa (40 psi).

This provided a total machine weight of about 12.7

Mg (14 tons).

Measurements and Analyses

On each site, all measurements and sampling were

made within the interior 40×40-m area of each

treatment plot. In late July to early August, the 5th-

year aboveground herbaceous vegetation was

collected from four 1.0-m2 subplots per plot, dried

at 75°C, and weighed. In September, after five

growing seasons, the basal diameter of all woody

stems (>15 cm height) was measured and recorded

by 2-mm diameter classes on eight 5.0-m2 subplots

per plot. Mean height of aspen suckers in each

diameter class was recorded to the nearest 5-cm

class. Aboveground biomass was estimated by

using allometric equations developed by Perala

and Alban (1994).

For each site, all subplot data were composited

and treatment effects were evaluated by analysis

of variance of the plot-level means. First, the overall effects of compaction level, OMR, and compaction-OMR interactions were evaluated. Few of the
62

interactions were significant, so the effects of compaction were evaluated across OMR levels, and

the effects of OMR were evaluated across compaction levels. Comparisons among means were made

with the Least Significant Difference procedure at

the 95 percent confidence level (Analytical Software 1998).

Results and Discussion

Soil Compaction

The objective of the compaction treatments was to

increase bulk density of the surface soil by either

15 percent or 30 percent without damaging the root

systems by rutting. This was accomplished successfully on the Marcell, Ottawa, and Huron sites.

However, spring and early summer rainfall was

higher than normal in 1993 and delayed study installation on the Chippewa. The frequent rainfall,

and the desire to avoid rutting, caused numerous

delays in application of the treatments. Thus, the

suckers had begun to emerge by the time the soil

had drained sufficiently to complete the compaction

treatments, and many were broken by the machine

traffic.

Stand density—Soil compaction increased mean

sucker density on the clay and sand sites; however,

the differences were not significant on the sand

and only marginally significant ( p = 0.092) on the

clay (table 2). The compaction treatments also

tended to increase first-year sucker density in the

British Columbia study, but by the 4th year the differences by level of compaction were no longer

significant (Kabzems 2000a). Presumably, these

initial increases were due to minor root injury during compaction. Disturbance of aspen root systems and increased soil temperatures are known

to stimulate sucker production (Peterson and

Peterson 1992, Schier et al. 1985). Soil compaction significantly decreased sucker density on the

Chippewa installation, primarily because of the late

spring treatment. On this site, effects of the compaction treatments on reducing sucker density

were dramatic and not unlike many operational

logging jobs in the northern Great Lakes region

(Bates et al. 1990, 1993).

Diameter—Soil compaction tended to decrease

mean diameter of suckers on the fine-textured

soils, but the differences were significant only on

the Chippewa (table 3). The decreased growth on

these sites most likely is due to a combination of

direct and indirect effects (Greenway 1999). Sucker

growth could be reduced directly by reduced soil

aeration, and indirectly by the increased sucker

density. In contrast, the compaction treatments

tended to increase mean basal diameter on the

Huron sands, despite the substantially greater

stand density (table 2). On coarse-textured soils,

low to moderate levels of compaction will convert

a portion of the macropore space to micropores,

thereby increasing the water-holding capacity of

the soil, thus decreasing water stress in the regeneration (Powers and Fiddler 1997, Powers 1999).

We emphasize that these experimental levels of

compaction are well below those encountered on

major skid trails and landings found on conventionally harvested sites (Stone et al. 1999). On those

areas, we have measured substantial reductions

in both sucker density and growth. Moreover, the

effects are likely to persist for decades (Grigal

2000), a century (Sharrett 1998), or possibly longer

(Curran 1999).

Height—As with diameter, the compaction treatments tended to decrease mean height of suckers

on the fine-textured soils, but the differences were

significant only on the Chippewa (table 4). Likewise, the decrease can be attributed to the combination of reduced soil aeration and increased

sucker density. On the Huron sands, increased

water-holding capacity of the soil and decreased

water stress in the suckers would account for the

small but consistent increases in sucker height with

level of compaction. Both trembling and bigtooth

occur on this site, but the differences in diameter

and height were not significant, so they were analyzed together.

Table 2—Mean 5th- year sucker density (k ha-1)

by level of compaction

Compaction National Forest

Level Ottawa Chippewa Huron

None 19.7a 33.2c 20.5

Light 28.9 12.6b 26.8

Heavy 28.6 4.4a 25.4

ANOVA p 0.092 0.000 0.123

a Treatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.
63

Biomass—The compaction treatments produced

little difference in dry weight of aspen on the clay

soil, but dramatic differences on the silt loam, primarily due to the delayed application of the treatments (table 5). On these clay sites, rutting has

been more detrimental to aspen regeneration and

growth than has compaction (Stone and Elioff

2000). On the sand site, compaction resulted in

slight, but non-significant increases in aspen biomass. Again, the differences among sites were far

greater than those of the compaction treatments.

Comparison of the non-compacted plots, for example, illustrates a 10-fold difference in potential

aspen productivity between the least productive

clay soil and the most productive silt loam. Likewise, despite the relatively small (<5 feet) difference in aspen site index, 5th-year aspen biomass

on the sand was four times that on the clay site.

Organic Matter Removal

Stand density—Winter harvesting by MBH produced abundant aspen regeneration on all three

sites. After five growing seasons, sucker density

ranged from 10,000 (10 k) to 22 k ha-1 (table 6).

For perspective, with uniform distribution, the 10 k

stems ha-1 on the Chippewa is equal to a 5-year-old

sucker on every m2 of the site. The TTH and FFR

treatments further increased sucker density, frequently at the expense of the associated commercial species. The differences were marginally

significant (p = 0.102) on the clay soils on the

Ottawa, highly significant on the silt loam on the

Chippewa, and non-significant on the sand soils on

the Huron. Graham et al. (1963) considered a 1st-

year sucker density of 15 k ha-1 (6 k ac-1) as minimal stocking and 30 k ha-1 (12 k ac-1) as optimal.

The FFR treatment resulted in a 1st-year sucker

density of >260 k ha-1 on the loamy sand site in

Table 3—Mean 5th-year sucker diameter

(at 15 cm) by level of compaction

Compaction National Forest

Level Ottawa Chippewa Huron

None 11.1a 21.6 c 15.9

Light 9.5 13.7 b 16.7

Heavy 9.2 10.9 a 17.0

ANOVA p 0.168 0.000 0.519

a Treatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.

Table 4—Mean 5th-year sucker height (cm) by

level of compaction

Compaction National Forest

Level Ottawa Chippewa Huron

None 134a 301c 218

Light 112 171b 223

Heavy 103 123a 238

ANOVA p 0.111 0.000 0.427

aTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.

Table 5—Mean 5th-year sucker dry weight

(kg ha-1) by level of compaction

Compaction National Forest

Level Ottawa Chippewa Huron

None 1,380a 13,260 b 4,630

Light 1,410 2,290 a 5,490

Heavy 1,260 330 a 5,870

ANOVA p 0.941 0.000 0.267

aTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.

Table 6—Mean 5th -year sucker density (k ha-1)

by level of organic matter removal

National Forest

Treatmenta Ottawa Chippewa Huron

MBH 20.2b 10.0 a 21.9

TTH 22.7 17.3 ab 24.9

FFR 30.8 22.9 b 25.9

ANOVA p 0.102 0.007 0.425

aMBH, merchantable bole harvest (10 cm top); TTH, total tree

harvest; FFR, total vegetation plus forest floor removal.

bTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.
64

northern Minnesota (Alban et al. 1994), and about

220 k ha-1 in British Columbia (Kabzems 1996),

most likely due to increased soil temperatures

and removal of competing vegetation (Kabzems

2000b). By the 4th year, sucker density had declined to about 55 k ha-1 in British Columbia

(Kabzems 2000a), and by the 5th year, to about

40 k ha-1 in Minnesota (Stone and Elioff 1998).

Diameter—Mean basal diameter (at 15 cm) tended

to be greater with TTH on the fine-textured soils,

although the difference between MBH and TTH

was not significant on the Ottawa clay (table 7).

The aspen on the Huron sands responded differently than those on the other sites. Mean diameter

was significantly greater with the MBH treatment

and declined with increasing level of OMR, as indicated by the 4th-year data (Stone et al. 1999). In

fact, the smallest mean diameters occurred with the

FFR treatment on all sites, indicating a potential

problem of sustaining productivity with repeated

total tree harvesting, particularly on sand soils.

Height—On the fine-textured soils, mean sucker

height on the TTH plots was significantly greater

than the MBH plots (table 8). As with diameter,

mean sucker height on the sand site was significantly greater in the MBH treatment and declined

with increasing level of OMR. This raises the question of whether the additional biomass removed by

total tree harvesting is worth the cost in soil resources—nutrients, organic matter, and waterholding capacity (Stone et al. 1999). On both the

Chippewa and Huron sites, the lowest mean height

was in the FFR treatment, partially due to high

sucker densities and the resulting intra-clonal competition. Stone et al. (2001) found that retaining 18

to 38 dominant aspen ha-1 (7 to 15 ac-1) reduced

first-year sucker density by about 40 percent and

increased their basal diameter and height growth

by about 30 percent.

Biomass—Dry weight production per unit area

integrates sucker density, diameter, and height in a

single value. On the fine-textured soils, aspen dry

weight was non-significantly greater with TTH

(table 9). On these sites, the TTH treatment produced intermediate sucker densities with greater

mean diameter, height, and dry weight, while total

woody vegetation plus FFR produced greater numbers of suckers, but with lower mean diameter,

height, and dry weight. On the sand site, MBH produced the lowest number of suckers with significantly greater mean diameter and height and dry

weight. The differences among sites were much

greater than the treatment effects within sites. For

example, mean (all treatments) 5th-year aspen dry

weight on both the sand, and the silt loam site was

greater than four times that of the clay.

Table 7—Mean 5th-year sucker diameter (at 15

cm) by level of organic matter removal

National Forest

Treatmenta Ottawa Chippewa Huron

MBH 10.0 bb 15.5 b 19.1 b

TTH 11.5 b 17.9 c 15.4 a

FFR 8.5 a 12.8 a 15.0 a

ANOVA p 0.017 0.000 0.001

aMBH, merchantable bole harvest (10 cm top); TTH, total tree

harvest; FFR, total vegetation plus forest floor removal.

bTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.

Table 8—Mean 5th-year sucker height (cm) by

level of organic matter removal

National Forest

Treatmenta Ottawa Chippewa Huron

MBH 104 ab 195 a 263 b

TTH 138 b 234 b 214 a

FFR 105 a 167 a 201 a

ANOVA p 0.036 0.001 0.002

aMBH, merchantable bole harvest (10 cm top); TTH, total tree

harvest; FFR, total vegetation plus forest floor removal.

bTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.

Table 9—Mean 5th -year sucker dry weight (kg

ha-1) by level of organic matter removal

National Forest

Treatmenta Ottawa Chippewa Huron

MBH 980b 4,950 6,200 b

TTH 1,610 6,710 5,140 ab

FFR 1,300 4,220 4,650 a

ANOVA p 0.376 0.230 0.082

aMBH, merchantable bole harvest (10 cm top); TTH, total tree

harvest; FFR, total vegetation plus forest floor removal.

bTreatment means followed by the same letter, or without letters,

do not differ significantly at the p = 0.05 level.
65

Summary and Management Implications

Soil Compaction

Responses to soil compaction differed greatly

among sites. Compaction prior to sucker emergence tended to increase sucker density, but after

they had emerged, machine traffic drastically reduced sucker density, diameter and height growth,

and biomass production; the differences were

highly significant after five years. Compaction on

the clay site produced small, but non-significant

reductions in sucker diameter and height. On these

kinds of soils, rutting has shown much greater impacts on aspen regeneration and growth than has

compaction. In contrast, the levels of compaction

applied on the sand site produced small, but nonsignificant increases in sucker diameter, height,

and biomass. However, the more severe compaction that routinely occurs on major skid trails and

landings, severely reduces both sucker density and

growth. Moreover, the effects are likely to persist

for decades to a century or longer. Thorough preharvest planning is required to designate these

areas—and to minimize the area affected—in order

to sustain the future productivity of these sites.

Organic Matter Removal

Harvest intensity and OMR significantly affected

one or more of the regeneration parameters on

each site, and the responses differed greatly by

site. These 5th-year data illustrate much larger differences in productivity between sites than might

be expected from site index data. Increasing levels

of OMR increased sucker density on all sites. On

the fine-textured soils, 5th-year sucker diameter and

height were greater in the TTH treatment. On the

sand soil, both the TTH and FFR treatments significantly reduced mean diameter and height. In fact,

the FFR treatment generally showed the smallest

diameter and height on all three sites. Treatment

differences in 5th-year aspen biomass were not

significant on the fine-textured soils, but declined

significantly with increasing level of organic matter

removal on the sand. This raises the question of

whether the additional biomass gained by total tree

harvesting is worth the cost in soil resources—

nutrients, organic matter, and water-holding capacity. The question also needs to be addressed in

other forest types on sand soils, such as jack pine

(Pinus banksiana Lamb.) in the upper Great Lakes

region.

Acknowledgments

Special thanks to Dave Alban (retired), who initiated the LTSP program in the Lake States, and to

John Elioff, Deacon Kyllander, and Jim Robl for the

many long hours dedicated to installing and maintaining these studies. Robert Wagner and Sarah

Mase, Ottawa National Forest; Dave Shadis,

Chippewa NF; and Joe Gates, Huron-Manistee NF,

provided invaluable assistance and financial support during the first five years of this long-term

study.

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National Soil Survey Center: 236-241.
68

Reserve Tree Method Produces Abundant Aspen Regeneration

and Increases Early Growth

Douglas M. Stone

Author

Douglas M. Stone is a research forester, North Central Research Station, 1831 Highway 169 East,

Grand Rapids, MN 55744.

Abstract

A reserve tree method (RTM) of harvesting was installed in six 65- to 75-year-old aspen-dominated stands

to determine if retaining 10 to 15 dominant aspen/acre would decrease sucker density to facilitate restoration of a conifer component. After the first full growing season following harvest, 96 percent of the harvested areas were stocked; sucker density averaged 27,000 (27 k)/acre vs. 38.2 k/acre on a clearcut

control, 41 percent less. Basal diameter of dominant suckers averaged 0.45 in., 28 percent greater than

the control, and mean height was 60 in., 33 percent greater. The control site had 3.1 k stems/acre of associated commercial species vs. 5.8 k on the RTM sites, an 87 percent difference. Four of the six stands have

been planted; first-year survival ranged from 88 percent to near 100 percent. The RTM shows promise for

reducing sucker density, increasing their early growth, maintaining species diversity, and providing abundant regeneration of commercial species on a high proportion of the areas harvested. Early results indicate

that the RTM can facilitate restoring a component of native conifer species in these ecosystems.

Keywords: Partial cutting, aspen management, conifer establishment, ecosystem restoration, silviculture.

sprouts of associated hardwood species (Graham

et al. 1963). Effective fire control beginning in the

1920s permitted these stands to develop into the

present-day second-growth forests dominated by

aspen.

Throughout much of the region, the abundance of

aspen reduces the landscape diversity associated

with more natural, conifer- and northern hardwooddominated landscapes. Resource managers are

seeking silvicultural alternatives to conventional

clearcutting, and ecologically sound and cost-effective means to reestablish a component of native

conifer species on some of these sites. Reestablishing a component of native conifers in these

ecosystems is viewed as a step toward ecosystem

restoration, so that stand-level species composition

is somewhat closer to that prior to the logging and

wildfires of a century ago. We report data on aspen

regeneration the first full growing season after harvesting six stands using a reserve tree method

(RTM) on the Superior National Forest in northern

Minnesota.

Introduction

Throughout the northern Great Lakes region, most

of the forest types are far different from those of a

century ago. Depending on location, the pre-settlement species growing on well-drained, medium- to

fine-textured soils of northern Minnesota, Wisconsin, and Michigan were predominantly shade-tolerant conifers including white pine (see Appendix for

scientific names), eastern hemlock, and northern

white-cedar; and tolerant hardwoods dominated by

sugar maple, red maple, yellow birch, and basswood (Albert 1995, Coffman et al. 1983, Kotar et al.

1988). White spruce, balsam fir, white ash, and

American elm were common associates. Without

stand-replacing disturbances (primarily fires), the

aspens (trembling and bigtooth) occurred as minor

associates (Braun 1950).

During the late 19th century, exploitative logging,

initially of conifer species, created conditions for

slash-fueled wildfires that swept over large areas of

the region, destroyed advance regeneration of the

former species, and resulted in “brushlands” comprising predominantly aspen suckers and stump
69

Traditional Management

The aspens are shade-intolerant, rapidly growing,

short-lived species that regenerate by root suckers

following removal of the parent stand (Perala and

Russell 1983). Suckers exhibit more rapid early

height growth than seedlings or sprouts of associated species, so they typically form the dominant

overstory during the early and mid-stages of stand

development. On medium- and fine-textured soils,

pure aspen stands are rare; most include a component of the more tolerant, longer-lived conifer and

northern hardwood species typical of these sites in

the absence of disturbance. On most commercial

forest lands in the Lake States, aspen is managed

for wood products or for a combination of fiber and

wildlife habitat. Where wood production is a primary objective, the stands normally are harvested

by a silvicultural (complete) clearcut of all species

and the aspen is regenerated from root suckers.

Presumably, the procedure can be repeated and

the aspen maintained indefinitely (Perala and

Russell 1983), provided the root systems are not

damaged by severe soil disturbance during logging

(Bates et al. 1989, Stone and Elioff 2000).

Thus, in the Great Lakes region, aspen management has been viewed rather simplistically—

clearcut a mature stand, let suckers regenerate the

site, wait, and then clearcut again when the stand

matures—no site preparation, no cleaning, no thinning, no pest control, little thinking (Cleland et al.

2001). However, clearcutting at frequent (40- to 60-

year) intervals to maintain single species stands in

an early successional state counters several of the

objectives of ecosystem management (e.g., Irland

1994) by interrupting natural processes and “resetting the successional clock” (Mladenoff and Pastor

1993). Many stakeholders object to clearcutting

and to single species management because of

visual quality and aesthetic values. Extensive loss

of the conifer component from much of the forest

area of the Lake States region has caused concerns about ecosystem structure and function and

the diversity and quality of wildlife habitat (Green

1995, Mladenoff and Pastor 1993). Ruark (1990)

proposed a reserve shelterwood system to convert

30- to 35-year-old, even-aged aspen stands to twoaged stands, and to allocate limited site resources

(sunlight, nutrients, water, and growing space) to

fewer stems per unit area. The method had not

been tested or validated, but offers several potential advantages at different spatial scales (Stone

and Strand 1997).

A major objective of ecosystem management is

maintenance or enhancement of species diversity

(Hunter 1990, Kaufmann et al. 1994). Many resource managers in the northern Great Lakes region are seeking ways to reestablish a component

of native conifer species. Establishing these species on suitable sites would be a first step toward

restoring stand-level species diversity. Moreover,

total yields of mixed-species stands may well exceed those of aspen alone (Man and Lieffers 1999,

Navratil et al. 1994, Perala 1977). Natural regeneration of most conifers on these sites usually is

limited by lack of available seed sources. Development of planted seedlings frequently is hampered

by competition from dense stands of aspen suckers, shade-tolerant shrubs such as beaked hazel

and mountain maple, and herbaceous species.

As an alternative to conventional clearcutting, and

to facilitate reestablishing a component of native

conifer species on the Mighty Duck timber sale, the

LaCroix District on the Superior National Forest

decided to take an “adaptive management” approach and try an RTM to reduce the density of

aspen suckers, and thus, increase survival and

growth of planted conifers. The aspen was 65 to 75

years old, mature or overmature, and the stands

were losing net volume from mortality due to stem

decay. The residual aspen overstory will not be

salvaged.

Methods

In each stand, 7 to 15 dominant or codominant

aspen stems per acre were selected at a uniform

spacing of 50 to 80 feet and marked with paint

spots at the stump and at 6 to 8 ft. on the stem.

Prior to harvest, we established transects at 1.5

chain intervals across each stand, marked sample

points every 1.0 chain along each line, measured

the diameter of all living trees >4 in. density at

breast height (dbh) with a 10-factor prism, and recorded all saplings and shrubs >6 in. height on a

circular 5-m2 (54 ft.2) plot at each sample point.

Stand 9 included an intermittent drainage that

separated the RTM portion from a control portion
70

that received a silvicultural clearcut. Stands 1 and

7 were harvested during the summer (July 1997

and August 1998) and the other four during the

winter. During September, after the first full growing

season following harvest, we recorded the dbh and

height of each reserve tree within 1.0 chain west or

south of the transect lines. On each 5-m2 regeneration plot, we recorded the number of stems of all

commercial species >6 in. height, the basal diameter (at 6 inches), and height of the dominant aspen sucker on each. Each regeneration plot was

considered stocked if it included one (800/acre) or

more stems of aspen or other commercial species.

The data were summarized and means calculated

for each site.

Results and Discussion

The density of reserve trees ranged from 7.3 to

15.3/acre and averaged 11.6/acre on the six sites

(table 1). Site 1 was the first stand marked and fell

below the desired 10 to 15 trees/acre. However, as

the markers gained experience, their judgement of

spacing distance improved, and density on the

other five sites was close to the objective. Except

for the first stand, the residual basal area was consistently between 10.5 and 12.2 ft2

/acre, indicating

that markers can produce uniform results with relatively little training and experience. Except for site

11, the dbh and height data indicate better-thanaverage site quality. However, the regeneration

data (table 2) suggest that this stand may have

been younger than the others.

After the first full growing season following harvest,

sucker density ranged from 18,300 (18.3 k)/acre to

33.4 k/acre and averaged 27.0 k/acre on the six

RTM sites (table 2). Interestingly, the highest density occurred on a summer-logged site (1), and the

lowest on a winter-logged site (13). However, the

relatively low sucker density on site 13 most likely

is because 40 percent of the initial basal area consisted of associated species, predominantly paper

birch and red maple. Thus, in these areas there

would be few, if any, aspen roots present to produce suckers.

During the public comment period on the environmental assessment of the timber sale, there were

concerns that the RTM might severely reduce

sucker density and growth. These data indicate

clearly that this is not a problem. Graham et al.

(1963) considered a first-year sucker density of

6 k/acre as minimum stocking and 12 k well-distributed suckers/acre as optimal; using these criteria,

all six of the sites are more than fully stocked. A

mean basal diameter of 0.45 inches and height of

60 inches is excellent first-year growth. Moreover,

the greater diameter and height of suckers on the

RTM sites suggest that carbohydrate and nutrient

reserves in the parent root systems are, indeed,

channeled to fewer suckers, thereby increasing

their early growth as postulated by Ruark (1990).

Site 1 was logged during July 1997 and planted

with container-grown white pine in May 1998; firstyear survival was near 100 percent.

Table 1—Characteristics of reserve trees on the Mighty Duck sale

DBH

Site Number Height BA Density

Inches feet square feet/acre number/acre

1

a 100 15.0 88 9.4 7.3

7

a 150 11.5 66 12.2 15.0

9 108 13.5 80 10.7 10.0

11 150 10.6 56 10.5 15.3

13 129 12.2 67 11.8 12.8

17 171 15.2 93 12.2 9.3

Mean 135 13.0 75 11.1 11.6

a

 Summer logged
71

An objective of ecosystem management is conservation or enhancement of species diversity (Hunter

1990, Kaufmann et al. 1994). Dense stands of aspen suckers and their rapid early height growth

place the seedlings and sprouts of associated species at a competitive disadvantage. The nearly twofold difference in density of associated species on

the RTM sites (table 2) suggests that reserving a

portion of the overstory contributes, either directly

or indirectly, e.g., less machine traffic, to maintaining stand-level species diversity. While this is a

limited sample size, we have noted similar trends in

other studies (unpublished data on file).

Each of these stands was commercially harvested

using conventional logging equipment, i.e., mechanical fellers and grapple skidders. Except for

the second summer-logged site (7), >95 percent of

the regeneration plots were stocked with one or

more stems of aspen or associated commercial

species (table 2). In related studies designed to

monitor harvesting effects on site disturbance and

regeneration, 11 percent to 38 percent of sites

were occupied by roads, skid trails, landings, or

other heavily disturbed areas that remain nonstocked for several years following harvest (Stone

and Elioff 2000). A significant difference between

the contract for the Mighty Duck sale and other

typical national forest timber sales was the inclusion of a clause specifying a $75 penalty for damage to each reserve tree. The damage clause was

highly effective; except for an occasional broken

live limb, we noted little logging damage to reserve

trees. Operator awareness is critical to protecting

advance regeneration (Navratil et al. 1994). Enhanced operator awareness also may have contributed to the relatively low amount of rutting and

other severe soil disturbance, and in turn, to the

high proportion of the areas stocked with commercial species. Use of reserve tree, or other contract

modifications, to increase operator awareness of

site disturbance and silvicultural objectives merits

serious consideration.

Summary and Management Implications

Reserving 7 to 15 dominant aspen/acre in six commercially harvested stands resulted in: (1) little

logging damage to the reserve trees; (2) regeneration of aspen and associated commercial species

on 96 percent of the area; (3) first-year sucker density of 27.0 k/acre on the RTM sites vs. 38.2 k/acre

on the clearcut control; (4) mean sucker diameter

of 0.45 inches and height of 60 inches; and (5)

5.8 k stems/acre of associated commercial species vs. 3.1 k on the control site. Of the four stands

that have been planted, first-year survival ranged

from 88 percent to near 100 percent. The RTM

shows promise for reducing sucker density, increasing their early growth, maintaining species

diversity, and providing abundant regeneration of

commercial species on a high proportion of the

areas harvested. These early results indicate that

the RTM can provide stand conditions that are favorable for restoring a component of native conifer

species in these ecosystems.

Table 2—First-year regeneration on the Mighty Duck sale.

No. Aspen ACSa Total Percent

Site Plots Diam. Ht. Density Density Density Stocked

– – – Inches – – – – – Ten thousands per acre – – Percent

1

b 138 —c 59 33.4 5.0 38.4 99.3

7

b 101 0.38 46 21.8 5.5 27.3 90.1

9 109 0.40 49 31.4 5.0 36.4 95.4

11 98 0.56 76 29.7 7.5 37.2 99.0

13 102 0.37 50 18.3 7.4 25.7 95.1

17 187 0.58 80 27.4 4.4 31.8 95.7

Mean 122 0.45 60 27.0 5.8 32.8 95.8

Control 43 0.35 45 38.2 3.1 41.3 97.7

a

 Associated commercial species

b

 Summer logged

c

 Not measured
72

Application

From a landscape perspective, two-storied stands

comprising a mixture of species are aesthetically

more appealing to many people than clearcuts

and single species management. Maintaining partial stocking of the site can be less disruptive to

normal hydrologic (evapotranspiration) and nutrient

cycling processes; this is a critical factor on some

sites (Stone and Elioff 2000). Two-storied, mixedspecies stands provide structural diversity that

benefits several wildlife species. The portion of the

timber volume retained will reduce the sale volume

per unit area, so the Allowable Sale Quantity can

be distributed over a larger area. This will accelerate development of a more balanced age class

distribution and reduce the eminent breakup of

overmature stands. From a silvicultural and forest

health viewpoint, this is especially important to

those districts that are losing net volume from mortality due to stem decay.

Acknowledgments

We thank John Galazen, Don Potter, and Doug

Watt, LaCroix Ranger District, Superior National

Forest, for providing the background information to

install the RTM trial; the LaCroix District and the

Ruffed Grouse Society for financial support; John

Elioff, Ryan Ackerman, and Travis Jones for their

conscientious field and laboratory work; and Nancy

Olson for assistance with data processing and

analyses.

References

Albert, D.A. 1995. Regional landscape ecosystems

of Michigan, Minnesota, and Wisconsin: a working map and classification. Gen. Tech. Rep.

NC-178. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest

Experiment Station. 250 p.

Bates, P.C.; Blinn, C.R.; Alm, A.A. [and others].

1989. Aspen stand development following harvest in the Lake States region. Northern Journal

of Applied Forestry. 6(4): 178-183.

Braun, E.L. 1950. Deciduous forests of eastern

North America. Hafner. New York, NY. 596 p.

Cleland, D.T; Leefers, L.A; Dickmann, D.I. 2001.

Ecology and management of aspen: a Lake

States perspective. In: Shepperd, W.D; Binkley,

D.; Bartos, D.L. [and others], eds. Proceedings,

sustaining aspen in western landscapes. RMRSP-18. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky Mountain

Research Station: 81-99.

Coffman, M.S.; Alyanak, E.; Kotar, J. [and

others]. 1983. Field guide to the habitat-type

classification system for Upper Peninsula of

Michigan and northeast Wisconsin. Houghton,

MI: Department of Forestry, Michigan Technological University. 160 p.

Graham, S.A.; Harrison, R.P., Jr.; Westell, C.E.,

Jr. 1963. Aspens: phoenix trees of the Great

Lakes region. Ann Arbor, MI: The University of

Michigan Press. 272 p.

Green, J.C. 1995. Birds and forests: a management and conservation guide. St. Paul, MN:

Minnesota Department of Natural Resources.

182 p.

Hunter, M.L., Jr. 1990. Wildlife, forests, and forestry: principles of managing forests for biological diversity. Prentice-Hall, Englewood Cliffs, NJ.

370 p.

Irland, L.C. 1994. Getting from here to there:

implementing ecosystem management on the

ground. Journal of Forestry. 92: 12-17.

Kaufmann, M.R.; Graham, R.T.; Boyce, D.A., Jr.

[and others]. 1994. An ecological basis for ecosystem management. Gen. Tech. Rep. RM-246.

Fort Collins, CO: U.S. Department of Agriculture,

Forest Service, Rocky Mountain Forest and

Range Experiment Station. 22 p.

Kotar, J.; Kovach, J.A.; Locey, C.T. 1988. Field

guide to forest habitat types of northern Wisconsin. Madison, WI: Department of Forestry, University of Wisconsin and Wisconsin Department

of Natural Resources. 217 p.

Man, R.; Leiffers, V. 1999. Are mixtures of aspen

and white spruce more productive than single

species stands? The Forestry Chronicle. 75(3):

505-513.
73

Mladenoff, D.J.; Pastor, J. 1993. Sustainable forest ecosystems in the northern hardwood and

conifer forest region: concepts and management. In: Aplet, G.H.; Johnson, N.; Olson, J.T.

[and others], eds. Defining sustainable forestry.

Washington, DC: Island Press: 145-180.

Navratil, S.; Brace, L.G.; Sauder, E.A.; Lux, S.

1994. Silvicultural and harvesting options to

favor immature white spruce and aspen regeneration in boreal mixedwoods. Inform. Rep.

NOR-X-337. Natural Resources Canada, Canadian Forest Service, Northwest Region. 73 p.

Perala, D.A. 1977. Manager’s handbook for aspen

in the North Central States. Gen. Tech. Rep.

NC-296. St. Paul, MN: U.S. Department of Agriculture, Forest Service, North Central Forest

Experiment Station. 30 p.

Perala, D.A.; Russell, J. 1983. Aspen. In: Burns,

R.M., tech. comp. Silvicultural systems of the

major forest types of the United States. Agriculture Handbook 445. Washington, DC: U.S. Department of Agriculture, Forest Service: 113-115.

Raurk, G.A. 1990. Evidence for the reserve

shelterwood system for managing quaking aspen. Northern Journal of Applied Forestry. 7(2):

58-62.

Stone, D.M.; Elioff, J.D. 2000. Soil disturbance

and aspen regeneration on clay soils: three case

histories. The Forestry Chronicle. 76(5):

747-752.

Stone, D.M.; Strand, J.C. 1997. Monitoring the

mighty duck timber sale: a national forest–

conservation organization–research partnership.

In: Proceedings, communicating the role of silviculture in managing the national forests. Gen.

Tech. Rep. NE-238. Warren, PA: U.S. Department of Agriculture, Forest Service, Northeastern Forest Experiment Station: 186-189.

Appendix

Common and Scientific Names of Trees and

Shrubs

Balsam fir (Abies balsamea (L.) Mill.)

Red maple (Acer rubrum L.)

Sugar maple (Acer saccharum Marsh.)

Yellow birch (Betula alleghaniensis Britt.)

Paper birch (Betula papyrifera Marsh.)

White ash (Fraxinus americana L.)

Black ash (Fraxinus nigra Marsh.)

White spruce (Picea glauca (Moench) Voss)

Eastern white pine (Pinus strobus L.)

Bigtooth aspen (Populus grandidentata Michx.)

Trembling aspen (Populus tremuloides Michx.)

Northern white-cedar (Thuja occidentalis L.)

Basswood (Tilia americana L.)

Eastern hemlock (Tsuga canadensis (L.) Carr.)

American elm (Ulmus americana L.)

Mountain maple (Acer spicatum Lam.)

Beaked hazel (Corylus cornuta Marsh.)
74

Understory Vegetation Development Following Commercial

Thinning in Southeast Alaska: Preliminary Results from the

Second-Growth Management Area Demonstration Project

Richard R. Zaborske, Richard N. Hauver, Michael H. McClellan, and Thomas A. Hanley

Authors

Richard R. Zaborske is the regional silviculturist, Alaska Region, 709 West 9th Street, Juneau, AK 99801;

Michael H. McClellan is a research ecologist and Thomas A. Hanley is a research wiildlife biologist,

Forestry Sciences Laboratory, 2770 Sherwood Lane, Suite 2A, Juneau, AK 99801; and Richard N. Hauver

is a silviculturist, Tongass National Forest, 648 Mission Street, Ketchikan, AK 99901.

Abstract

Five commercial thinning demonstration sites in southeast Alaska were treated in 1984-85 to evaluate

commercial thinning treatments that could enhance the development of understory vegetation. The effects

of these treatments upon the availability and quality of Sitka black-tailed deer forage were also evaluated.

The five commercial thinning sites were re-assessed in 1998. The strip and strip + individual tree selection

(ITS) treatments had the highest total biomass, 2,291 pounds per acre and 2,138 pounds per acre, respectively. Most of the biomass of these two treatments consisted of conifers. The ITS treatment had 1,357

pounds of total biomass per acre, of which 782 pounds per acre were of shrub/fern/forbs, which had more

nutritional value for deer. The ITS treatment yielded better forage resources for deer (capacity for “deer

days”) than did any other treatment or the untreated control. Results from this study show that thinning

treatments can improve deer forage availability when compared to no thinning treatment and that individual

tree selection thinning can provide summer habitat for deer similar to the values provided by old-growth

forest.

Keywords: Thinning, active stand management, individual tree selection, strip thinning, Sitka black-tailed

deer, deer forage.

dying or being blown down by wind is more or less

a continuous process (Harris 1989). The oldgrowth forest is a succession of canopy gaps in

space and time. With the forest floor light environment continuously shifting, no one species or

group of species can gain a competitive advantage

over others and shade them out. This equilibrium

more or less continues until some extensive

canopy disturbance such as windthrow or clearcut

harvesting occurs.

New stand development after a major disturbance

such as clearcutting follows a general pattern. A

new cohort of advance regeneration and newly

germinated western hemlock and Sitka spruce

(>4000 trees/acre) reoccupy the disturbed site

(Oliver 1981; Alaback 1982a; Deal et al. 1991).

Following clearcutting, residual shrubs also respond with a rapid growth increase that peaks in

cover (Robuck 1975) and biomass (Alaback 1980)

between 15 to 25 years. Conifers begin to overtop

Introduction

Replacement of old-growth forest with even-aged

young-growth is a major management issue for

wildlife resources in Southeast Alaska. Several

economically and socially important species such

as the Sitka black-tailed deer are heavily dependent upon old-growth forests for sustenance and

cover. Other species such as the Alexander Archipelago wolf, prey upon Sitka black-tailed deer and,

thus, are indirectly dependent upon old-growth

forests. Forest managers are seeking answers as

to how well these species might adapt to younger

forests and how could active stand management of

young-growth stands bring about the desirable

habitat features of mature and old-growth forests.

The natural southeast Alaska forest environment is

characterized by a high-frequency, low-magnitude

disturbance regime (Brady and Hanley 1984). The

process of individual trees or small groups of trees
75

shrubs by 8 to 10 years and crown closure may be

complete by 25 years (Harris and Farr 1974). During this stage of stem exclusion, the decline of understory vascular plants is rapid, and their

elimination occurs in 25-35 years (Alaback 1980).

Continued suppression of understory vegetation

and tree regeneration may last for up to 100 years

with understory vegetation not becoming well developed until stands are 120-150 years old

(Alaback 1982b, 1984; Tappeiner and Alaback

1989).

The lack of light is probably the most important

factor limiting understory growth (Alaback 1980).

Light reaching the forest floor of a closed-canopy

conifer forest, even on a clear day, is but a small

fraction (1,000 luxes) of levels (50,000 luxes or

more) that fall in open areas (Klein 1979). It may

require 250 years or more for stands to achieve

old-growth overstory characteristics of widely

spaced trees and complex multi-layered canopies

that allow light of variable intensity to reach the

forest floor (Alaback 1984). These characteristics

promote the development of an understory shrub

and herb layer of oval-leaf blueberry, red huckleberry, bunchberry, fern-leaf goldthread, five-leaf

bramble, foamflower, skunk cabbage, and shield

fern, all of which are key plant species for deer

forage.

Precommercial thinning may delay the onset of the

stem exclusion stage and loss of understory for a

brief period if the thinning is performed when understory plants are well established. However, aggressive understory conifers will outgrow the other

species and shade them out, or the overstory

canopy will close and shade out the understory

(Deal and Farr 1993).

Prior to the 1950s, timber harvest practices in

southeast Alaska consisted mostly of selective

cutting of individual or small groups of trees to supply wood products for mining, fish canneries, and

lumber for local southeast Alaska communities.

Logging was mostly confined to easily accessible

areas along the shoreline and lower river valleys.

Harvested areas were generally less than 124

acres (Deal 1999).

The scale of timber harvest increased significantly

in the 1950s with the establishment of long-term

timber sale contracts on the Tongass National Forest. These 50-year contracts called for the harvest

of over 13 billion board feet (USDA FS 1979) and

construction of associated pulp mills in Ketchikan

and Sitka. The objectives of these contracts were

to provide a sound economic base in southeast

Alaska, provide year-round employment, and replace a portion of the highly defective old growth

with vigorous young growth to increase the productivity of the forest for wood fiber.

The scale of timber harvest in southeast Alaska

was further increased through passage of the

Alaska Native Claims Settlement Act in 1971. This

Act authorized the transfer of about 44 million

acres throughout the State of Alaska from Federal

management to private ownership. Native regional

and village corporations were given the opportunity

to select land holdings from National Forest System lands. Of the total 550,000 acres the Native

corporations selected from the Tongass National

Forest, 460,000 acres are estimated to be productive forestland. A primary objective of these Native

corporations was to provide an economic return to

their shareholders. Many Native corporations harvested their forestlands to help meet their objectives.

As of 2000, slightly over 654,000 acres in southeast Alaska have been harvested: 416,400 acres

on National Forest lands, 210,000 acres on Native

corporation lands, and 28,000 acres on State of

Alaska lands; all primarily using the clearcut

method (fig. 1). Clearcutting is well suited to the

timber species and conditions found in southeast

Alaska. Western hemlock and Sitka spruce’s thin

bark makes them susceptible to logging damage

and subsequent wound infection by decay fungi.

Their shallow roots (due to shallow soils) make

standing residual trees susceptible to windthrow.

The risk of windthrow increases when partial cutting opens up stands. Clearcutting disturbs less

area for a given amount of timber volume than

does partial cutting. Compared to other harvesting

methods, clearcutting is the most economical

method (Harris and Farr 1974).

To address the question of how could active stand

management of young-growth stands bring about

the desirable habitat features of mature and oldgrowth forests, an Alaska Region Silvicultural Development Group was established in 1982. The

objective of this group was to “...develop, implement, monitor, and demonstrate a program to monitor second-growth stands of hemlock and spruce

forests on the Tongass National Forest to increase
76

Figure 1–Acres harvested by decade and by ownership in southeast Alaska, 1950-2000.

Figure 2–Vicinity map, second-growth management demonstration area .

Canada 

Alaska 

Pacific Ocean 

Bering 

 Sea 

Beaufort Sea 

N 

Tongass National Forest 

0

50000

100000

150000

200000

Forest Service Native Corp. State

State 0 12166 5416 6712 3938

Native Corp. 0 0 0 98102 110175

Forest Service 24986 110590 116031 84849 76288

1950s 1960s 1970s 1980s 1990s

Acres 

Harvested 
77

timber production and improve wildlife habitat capability.” Emphasis was placed on implementing

commercial and precommercial thinning projects to

test their value for wildlife habitat improvement and

timber production. The precommercial thinning

projects were later abandoned because their remoteness caused logistical problems in monitoring,

and the Forestry Science Laboratory was conducting other studies that were intended to address the

values of precommercial thinning.

To achieve the above objective, the Second-growth

Management Area Demonstration Project was developed. The purpose of the project was two-fold:

to determine the effects of various commercial thinning treatments on understory diversity and abundance and to assess the effects of these treatments on deer forage availability. Five commercial

thinning sites on the Tongass National Forest were

chosen: three on Prince of Wales Island (POW)

and two on Kuiu Island (figs. 2 and 3). Because the

objectives of the study were to demonstrate the

effects of different commercial thinning treatments

on understory development for deer habitat, all

sites were located in high-value deer winter range.

All five sites were clearcut between 1890 and 1942

and commercially thinned in 1984 and 1985. Thinning treatments were: ITS—individual tree selection, trees thinned to 20- to 25-foot spacing (four

sites); strip + ITS—combination of 30-foot wide cut

strips alternated with 20- to 25-foot wide strips that

were thinned to 20- to 25-foot spacing (three sites),

and strip—alternating 20-foot cut strips and 20-foot

no-cut strips (two sites) (fig. 4). One unthinned control was also established at each of the five sites.

Table 1 displays the site name, year harvested,

year thinned, and treatment applied. Because commercial thinning was new to southeast Alaska, all

of the falling and yarding was performed through a

service contract to maintain better quality control

over the logging operation.

Methods

Aboveground measures of biomass for all vascular

species were obtained within 1.0-m2 quadrats

along transect lines established within each stand.

Spacing of quadrats varied with the size and shape

of each stand, but quadrats were spaced to ensure

a uniform sampling of the entire stand. Twenty

quadrats were used for herbs (forbs, ferns,

graminoids), and 30 quadrats were used for shrubs

and conifer seedlings. All aboveground biomass

was harvested and weighed (fresh weight) by species within each quadrat. For each shrub species

within each quadrat, a subsample of three stems

(cut at ground level) was separated into leaves

Pacific

Ocean

Prince of Wales

 Island

Kuiu

Island

Baranof

Island

Canada

N

Kuiu

Port Camden

Naukati

Shaheen

Gravelly Creek

Site Name

Figure 3–Location map, second-growth management demonstration area.
78

Table 1—Treatment locations and treatments applied

Treatment Site Location Year Harvested Year Thinned Treatment Applied

Gravelly Creek 1 POW Islanda 1920 1985 ITS

Gravelly Creek 2 POW Island 1920 N/A Control

Naukati 1 POW Island 1925 1985 Strip

Naukati 2 POW Island 1925 1985 Strip + ITS

Naukati 3 POW Island 1925 1985 Strip + ITS

Naukati 4 POW Island 1925 N/A Control

Shaheen 1 POW Island 1929 1985 Strip

Shaheen 2 POW Island 1929 1985 Strip + ITS

Shaheen 3 POW Island 1942 1985 ITS

Shaheen 4 POW Island 1929 N/A Control

Kuiu 1 Kuiu Island 1890 1984 ITS

Kuiu 2 Kuiu Island 1890 N/A Control

Port Camden 1 Kuiu Island 1935 1984 ITS

Port Camden 2 Kuiu Island 1935 N/A Control

a POW (Prince of Wales).

Figure 4–Schematic drawings of treatments.

Uniform individual tree

selection, 20- to 25-foot

spacing

(n = 4)

30-foot cut strips (100%

removal) interspersed 

with strips thinned to 20-

to 25-foot spacing

(n = 3)

Alternating 20-foot 

strips of no cut and cut

(n = 2)

IT Strip + Strip
79

(including flowers), current year’s twigs, and stems

(prior years’ growth) and weighed. A subsample

of three conifer seedlings for each species within

each quadrat was similarly separated into current

year’s growth and prior year’s growth and weighed.

Subsamples of fresh material were oven-dried each

day for each species to determine the dry weight

per unit fresh weight. All understory biomass measures are expressed in terms of oven-dry weight

(105oC).

Samples of the 18 most abundant understory species were collected within each stand in which they

occurred, separated into leaves, twigs, and stems

(shrubs), and current and prior years’ growth (conifers), and oven-dried at 40oC for nutritional analyses. Nutritional analyses were conducted by the

Range and Habitat Analysis Laboratory at Washington State University and included sequential

detergent analysis (Goering and Van Soest 1970,

as modified by Hanley et al. 1992) for fiber constituents and total nitrogen by the Kjeldahl method

for all forage samples. Digestible dry matter and

digestible protein were estimated with equations

from Hanley et al. (1992), without incorporating

effects of plant tannins on protein digestion.

The value of understory vegetation as food resources for deer was quantified with a nutritionally

based model for calculating the number of deer

days that could be supported by the food supply

(Hanley and Rogers 1989). One deer day equals

the forage needed to maintain one deer for one day

at a specified metabolic requirement without losing

weight. We calculated deer days for each stand

under two different levels of metabolic requirements: one for an adult female at maintenance

requirement (no weight gain or reproduction) and

one for a lactating adult female with one fawn (i.e.,

reproduction requirement). Lactation requires

higher average dietary standards of both digestible

dry matter (i.e., energy) and digestible protein. The

model makes no assumption about habitat other

than the input data for food resources: the biomass

of each forage species, its dry-matter digestibility,

and its concentration of digestible protein. Food

resources are considered as though they were

harvested and fed to captive deer.

Results

Total biomass. Figure 5 shows the mean total

biomass for the controls, treated stands, and seven

old-growth stands in coastal Alaska (Alaback and

Juday 1989). The strip and strip + ITS treatments

had the highest total biomass, 2,291 pounds per

acre and 2,138 pounds per acre, respectively. The

ITS treatment had 1,357 pounds of total biomass

per acre, and the control (unthinned) treatment

had 111 pounds per acre. When compared to old

growth, however, all treatments had less total biomass. The old-growth forest had 2,743 pounds per

acre of total biomass.

Biomass by plant groupings. Figure 5 also

shows biomass by plant groupings (forbs, ferns,

shrubs, and conifers) by treatment and the oldgrowth forest. The strip + ITS treatment produced

the highest amount of conifer biomass (1,894

pounds per acre) followed by the strip treatment

(1,947 pounds per acre), the ITS treatment (575

pounds per acre), and the control (21 pounds per

acre). The old-growth forest had 667 pounds of

conifer biomass. The ITS treatment produced the

highest amount of shrub/fern/forb biomass (782

pounds per acre), followed by the strip treatment

(345 pounds per acre), the strip + ITS treatment

(245 pounds per acre), and the control (90 pounds

per acre). All of these treatments produced less

shrub/fern/forb biomass than the old-growth forest

(2,072 pounds per acre).

Deer forage availability. Table 2 shows the deer

forage availability for each of the treatments. The

strip and strip + ITS treatments provided almost the

same deer forage availability, providing 161 and

160 deer days per acre, respectively. The ITS treatment provided 142 deer days and the control 26

deer days. All of these values however, were lower

than the 251 deer days provided by upland oldgrowth forest (Hanley and Hoel, 1996).

When the nutritional requirements of a fawn are

added in, the picture changes dramatically. The ITS

treatment provides the highest number of doe +

fawn days (34 days), followed by the control and

strip (six days each), and the strip + ITS provided

the fewest number of doe + fawn days (three days).

In comparison, the old-growth forest provides 30

doe + fawn days.
80

Discussion

Care must be taken in interpreting the results of

this demonstration project given the limited sample.

However, some general observations can be made:

• Commercial thinning, regardless of type, appeared to enhance habitat of deer when compared to no commercial thinning.

• Habitat for deer reproduction was best improved by the ITS treatment, when compared

to the other treatments and to no commercial

thinning. Forbs were the forage class of highest

nutritional value for deer–they typically contain

less total fiber, fiber that is more digestible,

and greater concentrations of digestible protein than all other forage classes (Hanley and

McKendrick 1983, Parker et al. 1999). The

number of deer days was strongly determined

by the biomass of forbs, and this was especially

true for the higher nutritional requirements of

lactating deer (reproduction). The difference in

carrying capacity (deer days) for reproductive

versus non-reproductive deer, therefore, was

much greater in treatments containing fewer

forbs in their understory than in forb-rich understories. Although shrubs in the old-growth

stands contributed more toward maintenance

requirements of deer than they did in any of the

thinning treatments, little of that shrub biomass

was sufficient for meeting reproductive requirements. Carrying capacity of the ITS treatment

for reproductive deer came very close to that of

the old growth. However, our analysis applies

only to summer conditions; deciduous leaves

and snow-covered plants are not available to

deer in winter.

• Opening the stand up too much, as in strip thinning, greatly increases the amount of conifer

regeneration produced.

• Total biomass is not a good measure of deer

forage resources. Forbs are the major determinant of carrying capacity for deer, and their

biomass determines how much use can be

made of the additional, lower quality foods such

as shrubs, ferns, and conifers.

0

500

1000

1500

2000

2500

3000

Control ITS Strip +

ITS

Strip OldGrowth

Treatment

Biomass (lb./ac.)

Forbs

Ferns

Shrubs

Conifers

Figure 5–Total biomass and biomass by plant groupings.

Table 2—Deer forage availability by treatment

Strip + OldControl ITS ITS Strip Growth

N= 5 4 3 2 7

Doe only

(days/ac) 26 142 160 161 251

Doe+1 fawn

(days/ac) 6 34 3 6 30
81

Acknowledgments

The authors would like to thank the following for

their support and assistance in this demonstration

project: Ellen Anderson, botanist, Forestry Sciences Laboratory, Juneau, Alaska; the Alaska Region Second Growth Management Program;

Tongass National Forest, Petersburg and Thorne

Bay Ranger Districts; the Alaska Region Tongass

Land Management Plan Studies Program; and the

Pacific Northwest Research Station Wood Compatibility Initiative.

References

Alaback, P.B. 1980. Biomass and production of

understory vegetation in seral Sitka sprucewestern hemlock forests of southeast Alaska.

Corvallis, OR: Oregon State University. 79 p.

Ph.D. dissertation.

Alaback, P.B.1982a. Dynamics of understory biomass in Sitka-spruce-western hemlock forests

of southeast Alaska. Ecology. 63: 1932-1948.

Alaback, P.B. 1982b. Forest community structural

change during secondary succession in southeast Alaska. In: Means, J.E., ed. Proceedings of

the symposium on forest succession and stand

development research in the Northwest.

Corvallis, OR: Forestry Research Laboratory,

Oregon State University: 70-79.

Alaback, P.A. 1984. A comparison of old-growth

forest structure in the western hemlock-Sitka

spruce forests of southeast Alaska. In: Meehan,

W.R.; Merrell, T.R., Jr.; Hanley, T.A., eds. Fish

and wildlife relationships in old-growth forests.

Proceedings of a symposium, Juneau, AK:

American Institute of Fisheries Research Biologists: 219-226.

Brady, W.W.; Hanley, T.A. 1984. The role of disturbance in old-growth forests: some theoretical

implications for southeast Alaska. In: Meehan,

W.R.; Merrell, T.R., Jr.; Hanley, T.A., eds. Fish

and wildlife relationships in old-growth forests.

Proceedings of a symposium, Juneau, AK:

American Institute of Fisheries Research Biologists: 213-218.

Deal, R.L. 1999. The effects of partial cutting on

stand structure and growth, and forest plant

communities of western hemlock-Sitka spruce

stands in southeast Alaska. Corvallis, OR:

Oregon State University. 191 p. Ph.D.

dissertation.

Deal. R.L.; Farr, W.A. 1994. Composition and development of conifer regeneration in thinned and

unthinned natural stands of western hemlock

and Sitka spruce in southeast Alaska. Canadian

Journal of Forest Research. 24(5): 976-984.

Deal, R.L.; Oliver, C.D.; Bormann, B.T. 1991.

Reconstruction of mixed hemlock-spruce stands

in coastal southeast Alaska. Canadian Journal

of Forest Research. 21: 643-654.

Deal, R.L.; Tappener, J.C. 2000. The effects of

partial cutting on structure and growth of western hemlock-Sitka spruce stands in southeast

Alaska. Forest Ecology and Management. 5486:

1-14.

Goering, H.K.; Van Soest, P.J. 1970. Forage

analyses (apparatus, reagents, procedures and

some applications). Agricultural Handbook 379.

Washington, D.C: U.S. Department of Agriculture, Agricultural Research Service.

Hanley, T.A. 1991. Old-growth forests and biological conservation in temperate rain forests of

North America. In: Maruyama, N.; Bobek B.;

Ono, Y. [and others], eds. Wildlife conservation:

present trends and perspectives for the 21st century. Proceedings, international symposium on

wildlife conservation in Tsukuba and Yokohama,

Japan: 65-68.

Hanley, T.A.; Hoel, T. 1996. Species composition

of old-growth and riparian Sitka spruce-western

hemlock forests in southeast Alaska. Canadian

Journal of Forest Research. 26: 1703-1708.

Hanley, T.A.; McKendrick, J.D. 1983. Seasonal

changes in chemical composition and nutritive

value of native forages in a spruce-hemlock

forest, southeastern Alaska. Research Paper

PNW-312. Portland, OR: U.S. Department of

Agriculture, Forest Service, Pacific Northwest

Forest and Range Experiment Station. 41 p.
82

Hanley, T.A.; Robbins, C.T.; Hagerman, A.E.

[and others]. 1992. Predicting digestible protein

and digestible dry matter in tannin-containing

forages consumed by ruminants. Ecology. 73:

537-541.

Hanley, T.A; Rogers, J.J. 1989. Estimating carrying capacity with simultaneous nutritional constraints. Res. Note PNW-RN-458. Portland, OR:

U.S. Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 29 p.

Harris, A.S. 1989. Wind in the forests of southeast

Alaska and guides for reducing damage. Gen.

Tech. Rep. PNW-GTR-244. Portland, OR: U.S.

Department of Agriculture, Forest Service,

Pacific Northwest Research Station. 40 p.

Harris, A.S.; Farr, W.A. 1974. The forest ecosystem of southeast Alaska, 7: Forest ecology and

timber management. Gen. Tech. Rep. PNW-25.

Portland, OR: U.S. Department of Agriculture,

Forest Service, Pacific Northwest Forest and

Range Experiment Station. 109 p.

Kessler, W.B. 1982. Wildlife and second-growth

forests of southeast Alaska: problems and

potential management. In: Wildlife and fisheries

habitat management notes. Doc. No. 110. U.S.

Department of Agriculture, Forest Service,

Alaska Region.

Klein, D.R. 1979. Ecology of deer range in Alaska.

In: Wallmo, O.C.; Schoen, J.W., eds. Sitka

black-tailed deer. Proceedings of a conference.

Juneau: U.S. Department of Agriculture, Forest

Service, Alaska Region: 25-32.

Oliver, C.D. 1981. Forest development in North

America following major disturbances. Forest

Ecology Management. 3: 153-168.

Parker, K.L.; Gillingham, M.P.; Hanley, T.A. [and

others]. 1999. Energy and protein balance of

free-ranging black-tailed deer in a natural forest

environment. Wildlife Monographs. 143: 1-48.

Robbins, C.T.; Hanley, T.A.; Hagerman, A.E.

[and others]. 1997. Role of tannins in defending

plants against ruminants: reduction in protein

availability. Ecology. 68: 98-107.

Robuck, W. 1975. Understory vegetation in

thinned and unthinned hemlock-spruce stands in

Alaska. Program Representative, Coop. Administration Study FS-PNW-1642. U.S. Department

of Agriculture, Forest Service, Pacific Northwest

Forest and Range Experiment Station: 5-8.

Tappeiner, J.C.; Alaback, P.B. 1989. Early establishment and vegetative growth of understory

species in western hemlock-Sitka spruce forests

of southeast Alaska. Canadian Journal of

Botany. 67: 318-326.

Appendix

Common and Scientific Names of Plants, Trees, and Animals

Common name Scientific name

Bunchberry dogwood Cornus canadensis L.

Fernleaf goldthread Coptis asplenifolia Salisb.

Five-leaf bramble Rubus pedatus Sm.

Foamflower Tiarella trifoliata L.

Oval-leaf blueberry Vaccinium ovalifolium Sm.

Red huckleberry Vaccinium parvifolium Sm.

Shield fern Dryopteris expansa (K. Presl) Fraser-Jenkins & Jermy

Skunk cabbage Lysichiton americanus Hultén & St. John

Western hemlock Tsuga heterophylla (Raf.) Sarg.

Sitka spruce Picea sitchensis (Bong.) Carr.

Alexander Archipelago wolf Canis lupis ligoni

Sitka black-tailed deer Odocoileus hemionus sitkensis
83

Artificial Regeneration of Northern Red Oak and White Oak on

High-Quality Sites: Effect of Root Morphology and Relevant

Biological Characteristics

Paul P. Kormanik, Shi-Jean S. Sung, Stanley J. Zarnoch, and G. Thomas Tibbs

Authors

Paul P. Kormanik is a silviculturist and Shi-Jean S. Sung is a research plant physiologist, Institute of

Tree Root Biology, Southern Research Station, 320 Green Street, Athens, GA 30602; Stanley J. Zarnoch

is a mathematical statistician, Southern Research Station, P.O. Box 2680, Asheville, NC 28802; and

G. Thomas Tibbs is a regional geneticist, Forest Management Unit, Southern Region, 1720 Peachtree

Road, NW., Suite 816 N, Atlanta, GA 30309.

Abstract

Northern red oak (Quercus rubra) and white oak (Quercus alba) are important components of high-quality

mesic sites and are essential as lumber species and hard mast producers. Regeneration of these species

has been difficult, and their absence in newly regenerated stands is a major concern of foresters and wildlife biologists. Several important biological traits of oak species may contribute to regeneration difficulties.

These primary determinable biological traits may be shade intolerance and aging, which affects their reproductive potential. These factors, coupled with incompatibility of closely related individuals, greatly hamper

natural regeneration efforts by decreasing adequate advance oak regeneration for future stands. Artificial

regeneration can significantly increase the oak component because large oak seedlings that exceed the

suggested size of advance oak regeneration can readily be produced in forest tree nurseries with specific

nursery prescriptions. Seedlings produced in this fashion can readily be evaluated. Those from the top 50

percent, based upon first-order-lateral root numbers, have proven to be very effective in artificial regeneration of stands, in establishing plantings for seed orchards, and in establishing mast-producing areas within

larger forested stands.

Keywords: Artificial regeneration, high-quality mesic site, northern red oak, nursery protocol, seedling

evaluation, site maintenance, white oak.

is significantly different and thus, the biological

requirements of the individual species must not be

addressed as “oak” requirements. The single biological attribute of all oaks, however, is the near

obligate requirement for full sunlight in order to

survive and to produce adequate early growth that

enables attainment of a dominant crown position.

We are going to restrict our discussion to NRO and

white oak (WO) (Q. alba) because these are the

two species we have studied the longest. We will

not present an extensive literature review of oak

because many have already been published. The

most recent oak proceedings edited by Loftis and

McGee (1993) contain detailed reviews on many

specific subjects that may be helpful in understanding, if not alleviating, specific regeneration problems. We will briefly describe the biological factors

that we found to be essential in regeneration of

Introduction

Much has been written about the difficulty of obtaining northern red oak (NRO) (Quercus rubra)

regeneration on high-quality mesic sites. But, in

spite of much effort, little has been accomplished to

change our “luck.” We believe that luck has little to

do with regenerating NRO. Instead, it is the biology

or ecology of the species that has been ignored in

attempts to find procedures that work consistently

and can be prescribed with some degree of confidence.

Perhaps one of the basic problems is that “oak”

tends to be used as a generic term that connotates

a commonality among all species resulting in ignoring individual species’ silvicultural and ecological

requirements. The silviculture of swamp chestnut

oak (Q. michauxii), turkey oak (Q. laevis), and NRO
84

NRO and WO on high-quality mesic sites. These

two species have contrasting biology but also

share many common attributes. In this context,

we will discuss several important factors involved

in NRO and WO regeneration. These factors are:

1) biological constraints; 2) nursery practices; 3)

acorn availability; 4) seedling evaluation; and

5) pre and post planting site maintenance. We will

present data on a few current cooperative studies

between the Institute of Tree Root Biology (ITRB)

and Southern Region of the USDA Forest Service.

Background

The basis for our research, as well as most oak

regeneration research for the past 40 years, is the

work by Sanders (1971, 1972) who demonstrated

the importance of advanced oak regeneration before stands are harvested. His work was done primarily on lower quality sites (site index = 65 base 50)

where competition from faster growing species was

minimal. Even on these sites, however, considerable time and effort were required to build up the

advanced regeneration required to assure oak

presence in future stands.

Johnson (1981) attempted to produce nursery

grown oak seedlings of sufficient sizes to mimic

Sander’s advance regeneration. Various multi-year

growing procedures were used to obtain adequate

stem dimension that was considered comparable

to Sander’s recommendation. The best seedlings

were then top clipped and root pruned to facilitate

shelterwood underplanting. However, competition

from faster growing species on better sites seriously reduced the effectiveness of his prescription.

Ultimately, the procedure was recommended for

use where oak site index(50) was 70 where faster

growing competitors were not present (Johnson

1993).

Loftis (1983) attempted to develop advanced regeneration on high-quality mesic sites through

natural regeneration techniques consisting of a

series of partial crown releases to encourage natural oak regeneration. Periodicity of acorn production and severe competition from faster growing

competitors were handicaps that reduced the effectiveness of this procedure. However, this procedure

clearly established that a shelterwood system was

very effective in obtaining hardwood regeneration

on high-quality sites with one drawback: NRO was

not being established in these stands.

Three major principles of NRO and WO regeneration emerged over the past 40 years. We recognized that: 1) advanced oak regeneration is

essential; 2) altered nursery practices might produce the required stock; and 3) faster growing

competitors would be a major impediment on highquality mesic sites where obtaining oak regeneration is so critical. The major goal when research on

NRO and WO began at the ITRB in the mid-1980s

was to develop a reliable nursery protocol that

would consistently produce seedlings of adequate

size for advanced oak regeneration in cleared areas. This nursery fertility protocol became, and

still remains, the keystone of our oak research

(Kormanik et al. 1994a; Kormanik et al. 1994b).

Its consistency in producing acceptable seedlings

made it possible to conduct research in physiology,

mineral nutrition, and development of 1-2 hectare

mast-producing areas that will provide for future

acorn production for oak regeneration efforts and

hard mast production for wildlife maintenance.

Biological Constraints

One of the biggest impediments to successful

NRO and WO regeneration on high-quality sites

is adequate sunlight: too little sunlight and oak

regeneration cannot survive, abundant sunlight and

the competitors take over the stand. This is closely

followed in importance by the reduction in acorn

production as the tree ages. When height growth

slows down after age 50, only several cm of the

current years’ branch tips may be available for

acorn development. This fact is simply overlooked,

and mature stands are maintained under the illusion that they are providing acorns for hard mast

and for regeneration.

Inbreeding in natural oak stands may be a most

critical problem that is rarely addressed (Cecich

1993). Acorns remain close to the trees that bore

them and thus, clumping of closely related oak can

be expected. It is now commonly believed that the

callose plugs that precede pollen tube penetration

through the styles’ transmitting tissue may be indicative of pollen incompatibility. This could be

brought about by selfing or pollination by closely

related individuals (Cecich 1993). The problem

may be common within many Quercus species and

not unique to NRO and WO.
85

Several studies showed that full-sun-grown NRO

seedlings have higher net photosynthesis rates

(Pn) than shaded seedlings (Crunkilton et al. 1992;

Kubiske and Pregitzer 1996; Sung et al. 1998).

Photosynthesis rates for 1- and 2-year-old NRO

and WO seedlings grown with 30 percent light

were about 65 percent of the Pn for full-sun-grown

seedlings (Sung et al. 1998). Two-year-old 30 percent-light-grown NRO seedlings had about half as

much total biomass as the full-sun-grown seedlings. More importantly, however, is that these

shaded NRO seedlings had different biomass allocation patterns than the sun seedlings. In two-yearold full-sun NRO seedlings 10, 30, 37, and 23

percent of dry weight was allocated to leaves, stem

plus branches, taproots, and lateral roots, respectively (Sung et al. 1998). However, in 30-percentlight-grown NRO, 14, 43, 34, and 9 percent of

biomass was found in these corresponding seedling components. The 14-percent reduction in lateral roots is important because it eliminates a

significant portion of the feeder root complex. Similar effects of shade on biomass allocation patterns

were observed in WO (Sung et al. 1998).

In addition to the reduction in feeder root development, understory oaks must adapt to full sun when

the overstory canopy is removed. With increasing

light intensity, choloroplasts engage a xanthophyll

cycle-mediated photoprotection mechanism to

safely dissipate the excessive absorbed light energy as heat. However, leaves from shade-grown

plants have smaller xanthophyll cycle pools and

lower photoprotection index values as compared to

sun leaves (Faria et al. 1996, Logan et al. 1996).

Sung et al.1997 reported that Pn for NRO planted

under hardwoods (less than 5 percent full sun) or

pine (less than 40 percent full sun) was 5 and 30

percent of the Pn from oaks planted in clearcut

areas. Similar results were found for WO. Oaks

under hardwoods had very small photoprotection

index (0.1), whereas oaks in the clearcuts had a

photoprotection index of 0.8 (Sung et al.1997).

Thus, release of oaks from the understory can result in at least 1-year delay in maximum photosynthesis because shade-grown oak chlorophyll

probably would not have been protected from sun

bleaching once the overstory canopy was removed.

With little ability to protect the leaves from sudden

increase in light intensity, and with small percentage lateral root biomass, it might take these released oaks several years to adapt to full sun and

begin rapid growth. However, in the presence of

faster growing competing species, these oaks will

soon be shaded.

Acorn Production

Obtaining adequate acorns for nursery research

can be a frustrating endeavor. Adverse environmental and edaphic conditions, predation, and

various insects, are known to destroy more than

95 percent of the acorns in a heavy mast year and

entire crops during poorer mast years. White oak

acorns rapidly germinate after abscission. The

radicles penetrate into the soil, and thus, it is not

unusual to obtain large cohorts of seedlings following a bumper mast crop. These seedlings usually

die within 2-5 years. Seldom, if ever, are such massive cohorts of NRO observed because the long

stratification period required for germination often

results in desiccation and reduced viability. Spring

controlled burning in NRO stands in the spring

after a heavy fall mast crop generally reveals abundant acorns but essentially none that germinated.

This is due to severe desiccation since their maturation and abscission. It is evident that acorn-producing areas are critical, and proper collection and

storage of acorns are essential if artificial regeneration is to be a viable alternative to natural regeneration.

Nursery Protocol

The development of a reliable nursery management protocol was considered essential even before problems encountered with acorn availability

were considered. The basic nursery fertility protocol was developed in the mid-1980s for sweetgum

(Liquidambar styraciflua) and with some modifications, still remains the keystone of our oak regeneration effort. Its consistency in producing reliable

seedling crops has permitted the development of a

biologically based seedling evaluation protocol.

The protocol has resulted in the establishment of 1-

2 hectares of oak mast-producing areas and other

stand regeneration prescriptions. It has also proven

successful in producing quality oak seedlings from

10 oak species and many other hardwoods

(Kormanik et al. 1994a, 1994b).
86

Although NRO and WO respond similarly to the

standard fertility protocol, WO must be watered

lightly almost daily during early spring in order to

obtain 80 cm or more heights. During this time,

seedlings are undergoing a lengthy period of extensive feeder root development without stem

elongation. If feeder root development is not encouraged, one can expect the substandard WO

seedlings that are characteristically being produced by forest tree nurseries. In contrast, the

same early watering regime for NRO will result

in too much early height growth and excessively

large seedlings. These contrasting responses to

watering regimes necessitate sowing these species in nursery beds under separate irrigation

lines. Acorn sowing for both species should be

completed very soon after collection. If drought

persists throughout the winter, occasional light

irrigation will be required to prevent NRO acorns

from desiccation and to prevent damage to the

developing taproot of WO.

Acorns are sown to obtain a bed density of 60-70/

m2 and seedling morphological development is

controlled by NH4 NO3 applications and irrigation.

For outplanting, we prefer NRO and WO to have a

minimum root collar diameter (RCD) of 8 mm,

height (HGT) of 0.80-1.2 m, and the first-order lateral root (FOLR) number should be at or above the

average for that group. The nursery soil is analyzed before each growing season, and all fields

are brought up to specifications. We are, thus, developing a data base for nutritional requirements

of individual oak species that are characteristically

produced in the Georgia Forestry Commissions’

(GFC) nurseries.

Seedling Evaluation

Seedling quality consistency at our experimental

nursery near Athens and the two GFC state forest

nurseries has permitted the development of a

seedling evaluation system. The evaluation system

is based on FOLR numbers and also specifies the

minimum RCD and HGT for both species. Firstorder-lateral-root morphology is a highly heritable

trait and is ideal for comparing progeny of halfsibling seed lots and comparing progeny from different mother trees (table 1). Although heritability

estimates only apply strictly to the experiments

from which they were obtained, consistently high

values from repeated tests tend to substantiate the

importance of a specific trait (Wright 1976).

Seedling RCD and HGTs have been the standard

criteria for evaluating seedling quality. However,

simple modification of bed density, fertility regime,

or irrigation schedules may affect these seedling

parameters, and thus, render their use questionable. First-order-lateral-root development remains

consistent for a given seedling bed density even

under different growing conditions and fertility regimes.

Tables 2 and 3 contain typical nursery data for

NRO and WO, respectively, progeny produced by

GFC using our protocol. Note the wide range in

specific growth parameters is found that if an individual seedling exceeds the mean FOLR for its

half-sibling group, then it will most likely also exceed the RCD and HGT means for that group. In

evaluating progeny from hundreds of mother trees,

seldom do more than 50 percent of the seedlings

meet or exceed our outplanting standards. The

seedlings from the lowest 30 percent of the crop

seldom have more than a single FOLR and usually

are less than 1/3 of the HGT and RCD of the better

50 percent of the crop. Evaluating and discarding

the poorest 30 percent of seedlings are rapid procedures effectively done at the nursery during lifting and packing.

Sowing by mother tree seedlots permits early

evaluation of the competitive ability of specific

progeny groups (tables 2 and 3). Characteristically,

sibling lots that perform poorly in the nursery environment develop poorly after outplanting. Mother

trees from future collections whose individuals produce few FOLR and are generally substandard in

both RCD and HGT are discontinued, e.g., mother

tree 2-23-850 in table 2. Conversely, potentially

Table 1—First-order lateral roots family means

broad sense heritability estimates for Quercus

rubra and Q. alba in several studies

Study Heritability Standard Error

Q. rubra

1 0.898 0.153

2 0.870 0.114

3 0.843 0.235

Q. alba

1 0.843 0.138

2 0.918 0.073

3 0.843 0.235

4 0.949 0.026

5 0.893 0.116
87

Table 2—Morphological and growth characteristics of 1-0 northern red oak (Quercus rubra)

seedlings grown in 1995

Seedling less

FOLR Number than meana RCD (mm) HGT (cm)

Family Mean Range % Mean Range Mean Range

1-14-915 6.4 0-26 58 9.8 3.9-18.7 125 22-223

2-10-540 5.7 0-23 54 8.4 3.7-15.8 135 40-262

2-19-630 4.6 0-25 57 9.0 2.9-17.1 131 43-238

2-23-850 2.3 0-25 72 6.2 1.0-16.9 73 8-207

2-29-565 5.2 0-24 58 9.8 3.2-19.2 134 18-260

2-6-735 4.0 0-16 63 9.1 3.4-17.6 117 28-211

3-3-526 4.9 0-19 54 9.1 3.3-15.7 114 33-243

4-2-902 3.6 0-15 63 8.4 3.6-15.2 124 46-223

4-4-882 4.0 0-19 57 8.8 3.9-16.4 126 47-243

4-14-2459 5.9 1-20 52 10.5 3.4-18.9 125 22-253

4-27-100 4.2 0-19 56 9.3 2.9-17.9 141 33-243

6-14-200 5.0 0-20 58 8.5 3.0-15.69 121 41-232

a The percentage of seedlings in a given family with their FOLR less than the mean FOLR number for that family.

Table 3—Morphological and growth characteristics of 1-0 white oak (Quercus alba) seedlings

grown in 2000

Seedling less

FOLR Number than meana RCD (mm) HGT (cm)

Family Mean Range % Mean Range Mean Range

ASO-5 6.7 0-28 53 9.3 2.7-18.6 86 14-198

ASO-16 5.8 0-27 56 10.3 2.0-19.0 89 12-180

ASO-18 4.8 0-28 56 9.8 2.6-19.8 98 22-183

ASO-42 5.2 0-42 55 9.2 2.1-22.4 90 8-188

SRS-585 3.6 0-26 56 8.2 2.3-16.8 82 21-158

SRS-588 4.2 0-24 57 8.5 2.7-15.6 81 11-153

SRS-592 4.7 0-29 57 8.7 1.6-17.8 88 7-161

SRS-593 4.0 0-25 56 8.4 1.1-15.1 77 7-161

SRS-596 4.2 0-23 65 6.8 1.1-15.3 47 6-139

SRS-597 4.4 0-26 56 8.8 2.7-14.9 93 23-159

SRS-598 2.6 0-17 57 8.2 2.2-15.2 84 20-178

SRS-599 5.2 0-29 57 8.4 1.6-16.0 83 7-163

SRS-601 3.3 0-17 51 8.9 2.5-14.3 77 15-135

SRS-602 3.3 0-14 53 8.6 2.4-15.5 71 12-145

SRS-603 5.0 0-29 57 8.7 1.2-15.4 85 10-152

SRS-606 3.6 0-28 59 8.1 2.3-15.6 87 14-141

SRS-607 3.6 0-29 56 8.9 2.0-16.3 75 6-144

SRS-608 3.4 0-17 57 9.9 2.6-16.2 92 19-153

a The percentage of seedlings in a given family with their FOLR less than the mean FOLR number for that family.
88

better progeny groups can be identified after a

single nursery growing season. In the 2000 nursery

season, we identified individual NRO selections

that had less than 15-20 percent substandard

seedlings. This is encouraging that inclusion of

such potent genetic material in seed orchards

should be effective in improving the number of

plantable seedlings from each nursery crop.

Establishing NRO and WO individuals in seed orchards from the very best individuals with the highest FOLR numbers has resulted in acorn production by age five. At age seven, individual WO have

produced sufficient acorns for nursery testing and

establishment of seed orchards by the GFC.

While seedling seed orchards have been very effective for both NRO and WO, grafted white oak

seed orchards maintained by the USDA Forest

Service at the Beech Creek Seed Orchard near

Murphy, N.C., have not been satisfactory in terms

of progeny development in the nursery (table 4).

Progeny from this grafted seed orchard have been

tested for 5 years, and germination normally varies

from 5-50 percent. Transplanting these progeny

even under ideal seed orchard conditions has not

resulted in acceptable growth in most areas. The

reason for this poor performance of acorns from

grafted material is unclear. Investigation into this is

needed since grafting specific individuals with outstanding attributes could be a valuable tree improvement tool.

Pre and Post Site Maintenance

The shelterwood method of naturally regenerating

hardwoods on high-quality mesic sites works well

except for lack of regeneration in the valuable oak

component. Left unattended, these two oak species

cannot compete against the faster growing competitor species (Loftis 1983). Unfortunately, neither

will artificially regenerated NRO or WO compete

under these same circumstances. They need abundant sunlight and minimal root competition to be

competitive. However, a clearcut followed by an

effective burn, if necessary, usually is sufficient to

maintain these large artificially regenerated oak

seedlings for 3-5 years. In all cases, however,

stumps should be treated with a silvicide to prevent

sprouting because no individual seedlings, regardless of their origin or phenotypic characteristics,

can successfully compete with stump sprouts of

yellow poplar (Lilodendron tulipfera), red maple

(Acer rubrum) or Carolina silverbell (Halesia

carolina) present on a high-quality mesic site. With

adequate pre-planting vegetation control, the oak

seedlings should be able to compete against individuals of seed origin for 3-5 years, but will usually

need additional release between ages 7-15.

Initial post planting maintenance is primarily concerned with stump sprouts, but by year two blackberries (Rubus spp.) and grape (Vitae spp.) on

Table 4–Morphological and growth characteristics of 1-0 white oak (Quercus alba) seedlings

from grafted mother trees

Seedling less

FOLR Number than meana RCD (mm) HGT (cm)

Family Mean Range % Mean Range Mean Range

KYWO 11 3.4 0-17 63 7.5 2.0-13.8 46 12-128

KYWO 31 3.0 0-19 66 8.4 3.0-15.3 35 8-104

NAWO-01 2.5 0-16 67 7.2 3.2-13.6 28 8-87

NAWO 23 4.1 0-22 62 8.2 2.9-15.2 48 8-142

NAWO-24 3.8 0-21 60 7.9 2.8-15.0 39 14-147

NAWO-28 2.1 0-18 72 6.5 2.5-11.6 24 6-68

NAWO-29 2.3 0-18 67 6.5 1.0-15.3 25 8-100

SAWO 3 3.9 0-27 61 8.7 3.6-18.0 39 12-110

SAWO 7 3.6 0-23 61 9.0 2.7-17.4 48 12-134

SAWO 12 2.8 0-16 58 7.4 2.4-13.0 36 11-112

SAWO 14 4.6 0-32 64 8.6 2.7-18.4 46 12-151

SAWO 28 6.2 0-36 64 8.4 2.2-19.3 45 12-171

aThe percentage of seedlings in a given family with their FOLR less than the mean FOLR number for that family.
89

specific sites can become a severe problem, especially when both occur simultaneously. To establish

seedling seed orchards, we prefer that no thinning

be attempted until acorn production is initiated

between ages 5-10. Acorn production under

such conditions has been achieved at ages 4-7 for

both NRO and WO. However, under forest conditions, age of acorn initiation is unknown but will

depend heavily upon crown competition and early

fertilization.

Current Trends of ITRB Research

The nursery protocol and its potential benefits used

in producing oak planting stock have been published elsewhere and need not be repeated here

(Kormanik et al. 1994a, 1994b). Close examination

of data in tables 1-3 reveals why a sound biologically based grading system is an essential first step

in developing an effective artificial regeneration

initiative. If a seedling cannot compete effectively in

an ideal nursery setting, it is unlikely to be competitive in the field under significantly greater stressful

conditions. This data can also serve as a wake-up

call to the difficulty in obtaining advance regeneration through traditional management procedures

where a high percentage of seedlings may be inherently poor competitors. Preliminary data suggest that late germinating acorns produce a

disproportionally large share of these substandard

seedlings.

Our initial NRO artificial regeneration study is 11

years old, and the results comparing seedling performance in a clearcut and in a shelterwood has

been presented at the 11th Biennial Southern Silviculture Research Conference (Kormanik et al., in

press). No pre or post planting maintenance was

performed beyond the initial treatment, except at

age 7 when a circle (0.9 m radius) was cleared

around each tree to release the dominant individuals in the clearcut. At the same time, the overstory

was removed from the shelterwood. Three years

after shelterwood removal, the 11-year-old NRO

seedlings had a mean HGT growth of approximately 0.60 m since outplanting. The mean HGT

for the best seedlings was 1.6 m and many were

overtopped by more rapidly growing competitors.

Comparable individuals established in the clearcut

had mean HGTs of 3.5 m and some of the dominant ones had HGTs of 5-6 m.

A NRO mast evaluation trial was installed in a

small clearcut established in a hurricane-damaged

stand below the scenic Brasstown Bald Visitor Center on the Chattahoochee National Forest near

Blairsville, GA. Progeny from 25 mother trees represented by 1250 half-sib progeny showed considerable growth differences. Unlike the 11-year-old

study, this regeneration study was maintained

regularly and the competition was effectively controlled through the third year, when the crowns

began controlling competition. Initial mean HGT

and RCD for these trees were 0.87 cm and 9.9 mm,

respectively. Mortality over the 5 years has been 21

percent due almost entirely to vole (Microtus spp.)

damage during years 1 and 2. At year 5, mean

HGT and DBH were 2.76 m and 22.9 mm, respectively. Almost every family had individuals 3.5 - 5.5

m in HGT with excessive crown competition developing in adjacent rows. Thinning will be initiated in

2001 because of this competition. Acorns have not

been observed as yet, and hopefully, maintenance

of competition-free crowns will encourage early

acorn production.

A second NRO mast evaluation study using 17

different half-sib progeny groups was established

in 1995 on an old pasture near Morganton, NC, in

cooperation with the NC Division of Forest Resources. There were 765 seedlings in this test.

Initial mean HGT and RCD were 0.94 m and 12 mm

with mean FOLR of 9.9. Mortality during the initial 5

years was 1.6 percent, and some of this was mechanical damage that occurred in the first year.

After the fifth growing season, mean HGT and DBH

were 5.3 m and 52.7 mm, respectively. Many families had individuals whose HGT exceeded 7.0 m

with DBH exceeding 90 mm at age 5. Crown competition was excessive after the sixth growing season, and thinning was necessary before the

seventh year growing season. An appropriate herbicide was used to control the fescue sod. In our

two other large studies that were planted where

herbicide use was not permitted, thousands of

seedlings died the first year due to excessive competition and allelopathic effects from heavy fescue

sod.

The initial WO planting established by the ITRB

that consists of progeny from 30 different mother

trees with 1200 seedlings has just completed its

third growing season in year 2000. When this study

was initiated, we did not know the importance of

early season irrigation. Mean HGT and RCD of the
90

nursery stock was 0.67 m and 9.8 mm, respectively,

with mean FOLR of 9.6. After three complete growing seasons, mean HGT and DBH were 1.87 m and

10.3 mm with a mortality rate of 9 percent. Progeny

from almost all families was well represented by

individuals with HGT and DBH exceeding 3.0 m

and 32 mm, respectively.

During year 1, herbicide usage on the site was not

permitted. Only stump sprouts in direct competition

with the planted seedlings were controlled by mechanical procedures. During the second and

third year, stump and root sprouts continued to be

serious competitors but by then, herbicide usage

was permitted on the sites. This treatment was

effective in maintaining the WO in a dominant

position.

Conclusions

A viable component of both NRO and WO are essential on high-quality mesic sites if we are to

maintain the biological diversity so critical to the

long-term health of the forests and organisms that

depend so heavily upon them for their existence.

Partial crown removals or single tree selection appear to be counter-productive as a procedure for

obtaining and maintaining these oak species as a

viable component. These oaks are intolerant of

shade and will continue to decline in numbers and

importance in future stands on these higher quality

sites if we fail to provide adequate stand conditions

that will permit them to be competitive.

Metric Equivalents

1 inch = 0.39 centimeters (cm)

1 foot = 0.304 meters (m)

1 inch = 25.4 millimeters (mm)

References

Barton, A.M.; Gleeson, S.K. 1996. Eco-physiology

of seedlings of oak and red maple across a topographic gradient in eastern Kentucky. Forest

Science. 42: 335-342.

Cecich, R.A. 1993. Flowering and oak regeneration. In: Loftis, D.L.; McGee, C.E., eds. Proceedings, oak regeneration: serious problems,

practical recommendations. Gen. Tech. Rep.

SE-84. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station: 79-95.

Crunkilton, D.C.; Pallardy, S.G.; Garrett, H.E.

1992. Water relations and gas exchange for

northern red oak seedlings planted in a central

Missouri clearcut and shelterwood. Forest Ecology and Management. 53: 117-129.

Demming-Adams, B.; Adams, W.W., III. 1992.

Photoprotection and other responses of plants to

high light stress. Annual Review of Plant Physiology and Plant Molecular Biology. 43: 599-626.

Faria, T.; Garcia-Plazaola, J.I.; Abadia, A. [and

others]. 1996. Diurnal changes in

photoprotective mechanisms in leaves of cork

oak (Quercus suber) during summer. Tree Physiology. 16: 115-123.

Gottschalk, K.W. 1994. Shade, leaf growth and

crown development of Quercus rubra, Quercus

velutina, Prunus serotina, and Acer rubrum

seedlings. Tree Physiology. 14: 735-749.

Johnson, P.S. 1981. Nursery stock requirements

for oak planting in upland forest. In: Proceedings, northeastern area nurserymen’s conference. Broomall, PA: Northeastern Area, State

and Private Forestry: 2-19.

Johnson, P.S. 1993. Sources of oak reproduction.

In: Loftis, D.L.; McGee, C.E., eds. Proceedings,

oak regeneration: serious problems, practical

recommendation. Gen. Tech. Rep. SE-84.

Asheville, NC: U.S. Department of Agriculture,

Forest Service, Southeastern Forest Experiment

Station: 112-131.

Kormanik, P,P.; Sung, S.S.; Kormanik, T.L.

1994a. Toward a single nursery protocol for oak

seedlings. In: McConnell, J.L., ed. Proceedings,

22nd southern forest tree improvement conference. Atlanta, GA: 114-123.

Kormanik, P.P.; Sung, S.S.; Kormanik, T.L.

1994b. Irrigating and fertilizing to grow better

nursery seedlings. In: Landis, T.D., ed. Proceedings, northeastern and intermountain forest and

conservation nursery associations. Gen. Tech.

Rep. RM–243. Fort Collins, CO: U.S. Department of Agriculture, Forest Service, Rocky

Mountain Forest and Range Experiment Station:

115-121.
91

Kormanik, P.P.; Sung, S.S.; Kormanik, T.L. [and

others]. 1997. Heritability of first-order lateral

roots in five Quercus: Effect on 1-0 seedling

quality evaluation. In: Steiner, K.C., ed. Diversity

and adaptation in oak species. Proceedings,

second meeting of URFRO Working Party

2.08.05, Genetics of Quercus. University Park,

PA: Pennsylvania State University: 194-200.

Kubiske, M.E.; Pregitzer, K.S. 1996. Effects of

elevated CO2 and light availability on the photosynthetic light response of trees of contrasting

shade tolerance. Tree Physiology. 16: 351-358.

Loftis, D.L.; McGee, C.E. 1993. Proceedings, oak

regeneration: serious problems, practical recommendations. Gen. Tech. Rep. SE-84. Asheville,

NC: U.S. Department of Agriculture, Forest

Service, Southeastern Forest Experiment

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appalachian mixed hardwood stands with

the shelterwood method. Southern Journal

of Applied Forestry. 7: 212-217.

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W.W. III. 1996. Acclimation of leaf carotenoid

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Pap. NC-79. U.S. Department of Agriculture,

Forest Service. 6 p.

Sanders, I.L. 1991. Height growth of new oak

sprouts depends on size of advanced reproduction. Journal of Forestry. 69: 809-811.

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rubra and Q. alba seedlings of different light

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and adaptation in oak species. Proceedings,

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Photosynthesis and biomass allocation in oak

seedlings grown under shade. In: Waldrop, T.A.,

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92

Chapter 3

Aquatic Systems
93

Does Red Alder Enhance Wildlife, Aquatic, and Fisheries

Resources in Young-Growth Western Hemlock-Sitka Spruce

Forests of Southeast Alaska?

Robert Deal, Mark Wipfli, Adelaide Johnson, Toni De Santo, Paul Hennon, and Thomas Hanley

Authors

Robert Deal is a research forester, Forestry Sciences Laboratory, P.O. Box 3890, Portland, OR 97205;

Mark Wipfli is a research ecologist, Adelaide Johnson is a hydrologist, Toni De Santo is an ecologist,

Paul Hennon is a research forest pathologist, and Thomas Hanley is a research wildlife biologist, Forestry

Sciences Laboratory, 2770 Sherwood Lane, Suite 2A, Juneau, AK 99801-8545.

Abstract

Red alder (Alnus rubra Bong.) appears to influence the productivity and community composition of younggrowth conifer forests and affect the major resources (timber, wildlife, and fishes) of forested ecosystems

in southeast Alaska. We propose that landscapes may be managed to concurrently enhance these resources. Historically, red alder has often been regarded as an undesirable species by forest managers and

has been thinned from riparian and upland forests. We present an integrated approach to study the function of young-growth forest ecosystems and to understand how alder influences selected trophic linkages

and processes in managed landscapes. We will assess the physical disturbances that are associated with

alder establishment. We will also investigate mixed red alder-conifer forests and determine if these forests

provide a greater biomass of understory vegetation and forage for herbivores (e.g., deer) and invertebrates

than young-growth conifer forests. We will determine the effect of mixed red alder-conifer forests on the

abundance of aquatic, riparian, and terrestrial invertebrates that provide food for fish, bats, and birds. We

will also determine if most red alder trees die standing (as opposed to uprooting or bole snapping), and

assess woody debris and sediment input in streams. We will investigate whether red alder in mixed stands

may enhance conifer growth and total wood production. The inclusion of red alder in young-growth stands

may allow clearcutting in areas where purely even-aged conifer forests would compromise wildlife, fish,

and aquatic resources.

Keywords: Red alder, young-growth forests, headwater streams, geomorphology, invertebrates, fish,

wildlife.

southeast Alaska, particularly in upland areas with

heavy soil disturbance. However, little information

is available about the growth and ecological role of

red alder in Alaska. Basic information on silvics,

stand growth and yield, tree species mixtures, succession, tree mortality and decay, and understory

vegetation is lacking, and most knowledge about

alder is based on information from other regions.

In the Pacific Northwest, red alder grows in both

pure and mixed stands, with pure stands typically

confined to stream bottoms and lower hill slopes

(Harrington et al. 1994). In Alaska, pure red alder

stands are rare, and alder is a frequent associate

in mixed alder-conifer stands with Sitka spruce,

western hemlock (Tsuga heterophylla (Raf.) Sarg.),

and western redcedar (Thuja plicata Donn ex D.

Don). Red alder has rapid early height growth, but

Introduction

Red alder (Alnus rubra Bong.), a relatively shortlived, shade-intolerant pioneer with rapid juvenile

height growth, is the most common hardwood tree

in the Pacific Northwest (Harrington 1990). It occurs mostly as a lowland species along the northern Pacific Coast, and its range extends from

southern California to southeast Alaska. In Alaska,

red alder is commonly found along beaches and

streams, on snow avalanche and landslide tracks,

and as a pioneer species with Sitka spruce (Picea

sitchensis (Bong.) Carr.), black cottonwood

(Populus trichocarpa (Torr. & Gray), and willows

(Salix spp.) on exposed mineral soils (Harris and

Farr 1974, Ruth and Harris 1979). Logging has

increased the amount of alder in the forests of
94

growth slows after the juvenile stage. Observations

of mature forests in the Pacific Northwest indicate

that alder trees may be replaced by longer-lived

conifers, and on an average site, associated conifers and red alder can attain the same height at

about age 45 years (Harrington 1990). The establishment and growth of shade-tolerant conifers

such as Sitka spruce and western hemlock probably control which successional trajectories will be

followed; however, the successional sequences in

mixed alder-conifer stands are not well understood.

In southeast Alaska, even-age forest management

has been used almost exclusively in the region for

wood production, and stands have been regenerated through clearcutting and natural reproduction.

However, the dense, uniform, even-aged stands

that quickly develop are recognized as having

broadly negative consequences for wildlife and fish

(Wallmo and Schoen 1980; Schoen et al.

1981,1988; Thedinga et al. 1989; Hanley 1993;

Dellasala et al. 1996). Canopy closure generally

occurs 25 to 35 years after cutting followed by a

nearly complete elimination of understory vegetation for 100 years or longer (Alaback 1982, 1984;

Tappeiner and Alaback 1989). Following canopy

closure above small streams, trophic status

changes from autotrophic (organisms manufacture

own energy) to heterotrophic (organisms are consumers) (Sedell and Swanson 1984, Hetrick et al.

1998). The removal of streamside trees also reduces the amount and size of large wood with the

subsequent loss of bird1 and fish habitat (Bryant

1985, Bisson et al. 1987). Changes in forest structure may result in an alteration of supply, storage,

and transport of woody debris and sediment

through processes including mass-wasting, windsnap and blow-down, and bank erosion (Smith et

al. 1993, Hennon 1995, Johnson et al. 2000).

There is increasing interest in developing forest

management practices that maintain or enhance

biodiversity and assure long-term sustainability of

forest products, wildlife, and aquatic resources.

Recent studies of mixed red alder-conifer stands

have indicated that different successional pathways

are possible following clearcutting in southeast

Alaska. These alder-conifer stands have both species-rich and highly productive understory vegetation with biomass similar to that of old-growth

stands of the region (Hanley and Hoel 1996, Deal

1997, Hanley and Barnard 1998). Habitat quality

for some small mammals in even-aged, alder-conifer stands may be equal to that of old-growth forests (Hanley 1996). Although inclusion of alder will

not provide mitigation for all wildlife-habitat problems (e.g., lack of snow interception for deer winter

range), it may accomplish more than is possible by

thinning even-aged conifer stands. Attempts to

reestablish understory herbs and shrubs through

thinning young-growth conifer stands have led to

mostly conifer regeneration with little new herbaceous colonization (Deal and Farr 1994). Further,

there may be more benefits with the inclusion of

alder in riparian forests. The abundance of terrestrial invertebrates is affected by the composition of

forest vegetation, and there is greater density and

biomass of invertebrates on some riparian plant

species (Mason and Macdonald 1982). In southeast Alaska, over half of the prey biomass ingested

by juvenile salmonids is terrestrial prey that fall into

streams from adjacent riparian vegetation, and forests with alder may produce more prey for salmon

than forests without alder (Wipfli 1997). If similar

invertebrate community responses occur in upland

forests, increased invertebrate production may

provide more food for animals including birds, bats,

small mammals, and fish downstream, thereby also

increasing vertebrate abundance and production.

We are using an integrated, comparative study of

alder-conifer stands versus pure conifer stands to

assess differences in physical disturbance history

associated with tree composition, stand structure

and tree mortality, understory vegetation, bird and

bat communities, and invertebrates, (e.g., food

resources) for fish, birds, and bats (figs. 1 and 2).

This study involves a broadly integrated research

program to address ecological processes that are

critical for the establishment and growth of alderconifer forests. An assessment of both forest disturbance history and geomorphic processes is

being used as a framework to evaluate habitat

1 De Santo, T. L. Unpublished data. On file with: Forestry

Sciences Laboratory, 2770 Sherwood Lane, Suite 2A,

Juneau, AK 99801.
95

Figure 1—Influence of alder in the ecosystem: vegetation, birds, bats, invertebrates, wood, and fishes.
96

changes in managed forests. We are evaluating

the role of headwater physical processes (Bilby

and Bisson 1998, Bisson and Bilby 1998) within a

landscape context to assess conditions necessary

for the establishment of mixed alder-conifer stands.

Critical processes for maintaining downstream fish

habitat are being assessed including the supply,

storage, and transport of wood and sediment (fig.

3). We also are determining the compatibility and

potential tradeoffs between the amount of red alder

in forests, the production of understory vegetation,

and growth and yield of Sitka spruce and western

hemlock. The potential of red alder as a ‘tool’ for

restoring important ecosystem functions in regenerating forests of southeast Alaska is being evaluated.

Approach

We are sampling across a continuum of alder-conifer mixtures using the composition of tree species

as a main site selection criterion to assess the role

of red alder in young-growth forests and to determine the effect of alder on forest and aquatic resources. We selected study areas in the Maybeso

and Harris watersheds, Prince of Wales Island,

Alaska, to reduce the range of site variability.

These watersheds were chosen because they have

large areas of relatively uniform stand age and site

productivity with a wide range of alder-conifer mixtures.

The objectives for each component of the study

requires specific selection criteria, but about half

of the sites are being used in common for all resources including timber, wildlife, and fish. Twelve

sites were selected and sampled during FY 2000

Alder ---------- Conifer 

Overstory species

Understory

Birds & bats

 Forest 

invertebrates

 Headwater 

 stream

invertebrates

 Fish and fish habitat Figure 2—Influence of alder on

ecosystem linkages and

processes.
97

and will be sampled again in 2001 to investigate

biological and physical linkages between terrestrial

and aquatic systems. We are describing and relating disturbance history with tree species composition. We are also installing overstory and understory plots to assess stand structure and growth,

tree species composition, understory plant diversity

and abundance, frequency and type of tree mortality, and wood decay. We are determining the abundance and types of invertebrates found in association with living and dead trees and leaf litter in

terrestrial and aquatic habitats, and characterizing

bird and bat activity by direct observation of foraging birds and electronic recordings of ultrasonic

emissions of foraging bats. Processes that transport wood and sediment to streams are being assessed in relation to fish habitat.

There are three main integrating themes of this

research: (1) influence of alder in the ecosystem—

vegetation, birds, bats, invertebrates, wood, and

fishes (fig. 1); (2) influence of alder on ecosystem

linkages and processes (fig. 2); and (3) flow of

wood among habitats–from uplands to lowlands

(fig. 3).

Methods

Methods are summarized by each major discipline.

More detailed information on specific objectives,

hypotheses, sampling methodology, and analyses

is contained in an unpublished study plan2.

Figure 3—Flow of wood among

habitats – from uplands to

lowlands.

2 Wipfli, M.S.; Deal, R.L.; De Santo, T.L. [and others].

2000. Managing young upland forests in southeast

Alaska for wood products, wildlife, aquatic resources and

fishes. Unpublished study plan for Wood Compatibility

Initiative. On file with: Forestry Sciences Laboratory,

2770 Sherwood Lane, Suite 2A, Juneau, AK 99801.

Live trees (uplands)

Tree mortality

Landslides

Dead trees

Wood products

Timber harvesting

Headwater stream 

 woody debris

 Forest floor

woody debris Riparian 

woody debris

Woody debris in anadromous streams (lowlands)

Removed

from forest

ecosystem
98

Wood Production, Vegetation, and Tree Disease

Stand density, tree-species distribution, and abundance are being assessed in 20 variable-radius

plots within each stand. The proportion of alder

basal area in young-growth stands is being analyzed in relation to stand density and wood production. Understory plant biomass data are being

collected in vegetation quadrats throughout the

stand. Biomass data is combined by stand and is

being analyzed to determine how the proportion of

alder basal area affects species richness and biomass of all vascular plants. Stand and tree growth,

tree regeneration, and tree height and diameter

distribution are being measured in five large fixedarea plots in each stand. Plot data is combined by

stand and is being analyzed to determine how the

proportion of alder basal area affects stand growth,

tree height and diameter growth, and tree regeneration. In addition, riparian overstory and understory vegetation are being sampled in fixed-area

plots along upper and lower 300 m reaches of each

of the 12 streams used in the aquatic and riparian

ecology studies. Vegetation immediately adjacent

to study streams is being analyzed and compared

with non-riparian vegetation.

Dead trees are being measured in variable-radius

and fixed-area plots to estimate species and size of

recent tree mortality for woody debris recruitment.

Trees as small as 3 cm diameter are included in

sampling because this is the minimum threshold of

“small woody debris” used in woody debris assessments (Gomi et al., in review). Tree mortality is

being classified as dead standing, broken bole, or

uprooted to investigate the dynamics of tree mortality and stand development. We are analyzing

whether stand composition influences the size or

species of trees that have died, and how the proportion of alder in young-growth stands influences

the amount and type of woody debris recruitment.

The presence and type of wood decay (white or

brown rot) from dead alder and conifers is being

recorded and quantified from the vegetation plots.

These two decays produce distinct physical residues that may differ in their influence on biological

processes. The proportion of total woody debris

recruited in both decay types is being estimated.

Aquatic and Riparian Ecology

Twelve small permanent streams (~10-20 ha subbasins) in upland forests across a range of 0-80

percent alder are being sampled for invertebrates

that colonize alder and conifer woody debris in

streams. Abundance and composition of aquatic

invertebrates are the response variables. Riparian

stands along these same 12 streams are being

sampled for abundance and composition of invertebrates that colonize riparian woody debris. Transport of aquatic and terrestrial invertebrates is also

being sampled between May and September, immediately upstream of fish habitats, to assess the

amount of food delivered by these headwater

streams to downstream fish habitats.

Terrestrial Invertebrates

Passive sampling of terrestrial invertebrates is being conducted in 12 stands of three forest habitat

types (conifer young growth, alder-conifer young

growth, and old growth) from May through September, a period during which invertebrates are developing and active. Traps on tree boles and foliage

clippings are being used to sample invertebrates

on all tree species (Sitka spruce, western hemlock,

western redcedar, red cedar, and red alder). Malaise traps are being used to sample flying insects.

The number of invertebrates in samples is being

quantified, and specimens measured (length) and

classified to family. These measures are being

compared among habitat types and tree species

within habitat types.

Wildlife

Breeding bird communities (bird abundance and

species composition) are being censused by the

point-count method (Verner 1985, Ralph et al.

1993) in 12 sites of three forest habitat types (conifer young growth, alder-conifer young growth, and

old growth). Census points, located >150 m apart

and >50 m from habitat edges are being visited

three times during the breeding season (May

through July). Species richness and abundance

are being compared among sites. An index of

relative nest predation among habitat types is being determined by placing artificial nests in four

stands of each habitat type. Nests are baited with

plasticine eggs to aid in the identification of nest

predators. Natural nests within each habitat type

are also being located and monitored. Nesting success is being analyzed by the Mayfield method

(Mayfield 1961, 1975) if adequate sample sizes are

obtained; simple percentage of success (e.g., number of successful nests/total number of nests) is

being calculated otherwise. To document possible

differences in diet and use of foraging substrates

between mixed alder-conifer and conifer stands, we
99

are observing foraging birds, documenting substrates used for foraging, and analyzing diets of

mist-net captured birds by using the stomach flush

method (Major 1990). Foraging observations and

diet analyzes are being coupled with analyses of

invertebrates collected on different tree species

within different habitats (see Terrestrial Invertebrate Section). Diet analyses will be particularly

useful should we find differences in the types of

invertebrates associated with different tree species

or habitats.

Bats are being censused with ANABAT II detectors

deployed within corridors where alder is a major

component of the adjacent forest vegetation (alder

treatment), and in paired plots within nearby corridors where alder is mostly absent (conifer treatment). Sampling duration will vary from 24 to 72

hours depending on bat activity, but is identical for

paired treatments. Total bat activity is the response

variable. It is also assumed to be a surrogate of

feeding activity and thus, is an index of the quality

of sites as bat foraging habitat.

Correlations between overstory and understory

variables are being determined from each alderconifer stand sampled in this study. Understory

variables include biomass and canopy coverage

of vascular plant species. Analyses will quantify

potential trade-offs between overstory structure

and understory variables. Understory species composition and biomass are being quantified in terms

of food value for deer (deer days per hectare) by

use of a nutritional model for deer habitat (Hanley

and Rogers 1989).

Fish

Thirteen streams are separated into three gradient

zones and are being sampled seasonally. All

streams are fed by headwater tributaries dominated

by alder or conifer riparian forests. The three gradient zones include: the general upper range of

salmonid habitat (gradient 7-15 percent); moderate

gradient reaches (gradient 3-7 percent); and floodplain reaches (gradient 0-3 percent). Fish densities

and species distribution are being compared

among treatments (alder vs. conifer) and among

gradient zones. Each stream is being surveyed

using a modified tier III survey (USDA FS 2001).

Key habitat measurements include large wood size

and volume (Gomi et al., in press), substrate composition, and pool metrics including area and residual depths.

Geomorphic and Landscape Processes

The association between disturbance history and

tree species composition is being assessed at 22

sites within three forest types (conifer young

growth, alder-conifer young growth, and old

growth). The relative magnitude of woody debris

and sediment inputs by various disturbance processes including landslides, blowdown, bank erosion, and tree death are being estimated (and field

verified) by using current inventories of landslides

and process models. Site characteristics described

include average slope gradient, substrate size,

landform type, landslide history, and an estimate

of contributing area. Pool formation in the upper

and moderate gradient zones of salmonid habitat

is categorized as no pools, one pool, or multiple

pools. Results for pool occurrence are being compared between alder- or conifer-dominated

streams.

Research Objectives

We are broadly assessing the influence of red

alder in the ecosystem and the linkages among

overstory and understory vegetation, birds, bats,

invertebrates, wood, and fishes (fig. 1). We are

investigating mixed red alder-conifer forests and

determining if these forests provide a greater biomass of understory vegetation and forage for herbivores (e.g., deer) and invertebrates than younggrowth conifer forests. We are assessing the effect

of mixed red alder-conifer forests on the abundance of aquatic, riparian and terrestrial invertebrates that are food resources for bats, birds, and

fish (fig. 2). We are determining if most red alder

trees die standing (as opposed to uprooting or bole

snapping), and examining the woody debris and

sediment input into streams. We also are investigating the flow of wood among habitats and the

linkages between tree mortality and woody debris

in riparian, headwater and lowland streams (fig. 3).

We are determining the effect of red alder in mixed

stands on conifer growth and total wood production. Our research is evaluating whether the inclusion of alder in young-growth stands may allow

clearcutting in areas where purely even-aged conifer stands would compromise fish, wildlife and

aquatic resources.

Management Implications

Although our current research focuses on younggrowth forests of southeast Alaska, the potential
100

exists to expand our understanding of the occurrence and role of red alder in unmanaged ecosystems to the landscape and regional levels. In

addition, our research approach of integrating disparate disciplines can be used as a framework to

study the role of alder in other regions or the manipulation of vegetation in relation to multiple, complex resource objectives. Knowledge gained from

this research may find management applications

elsewhere as summarized below.

Forest Vegetation

• Evaluate the compatibility and potential

tradeoffs in wood production and biodiversity

between conifer- and alder-dominated stands.

• Evaluate the relationship of stand structure and

composition of mixed alder-conifer stands to

wildlife, aquatic, and fisheries resources.

• Assess tree mortality and wood decay and

evaluate woody debris input for aquatic and

terrestrial forest habitats.

Hydrology and Geomorphology

• Relate disturbance history to composition of

forest vegetation.

• Develop improved criteria for riparian buffer

requirements.

• Develop guidelines for headwater channel

management.

Aquatic and Riparian Ecology

• Develop guidelines for restoring headwater

stream function and trophic biological and

physical processes that support fish and

wildlife.

• Develop guidelines for watershed restoration

management to protect salmonid habitat.

• Evaluate invertebrate diversity and abundance

and the potential for improving the insectivorous food base for fish and wildlife.

Terrestrial Invertebrates

• Evaluate vegetation for improving invertebrate

diversity and abundance.

• Evaluate invertebrate diversity and abundance

and prospects for improving insectivorous food

base for wildlife.

Wildlife Ecology

• Evaluate potential for improving nesting and

foraging habitat for birds in young-growth alderconifer forests.

• Evaluate potential of alder-conifer forests for

improving bat habitat.

• Improve wildlife habitat in young-growth forests

by increasing understory vegetation and food

resources for birds and mammals.

• Evaluate potential for mitigating losses of wildlife habitat from clearcut logging.

Acknowledgments

This research was made possible through funding

by the USDA Forest Service, Pacific Northwest

Research Station, Wood Compatibility Initiative.

We would like to thank all of the other principal

investigators in this project including Mark Schultz,

Mason Bryant, Winston Smith, and Rick Edwards.

We also want to thank Takashi Gomi, Oswaldo

Hernandez, Christian LeSage, Ewa Orlikowska,

Alison Cooney, and the numerous field personnel

who have provided invaluable assistance in the

project. We are grateful for early reviews of this

paper by Dave Hibbs, Winifred Kessler, and Steve

Wondzell.

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Chapter 4

Social Systems
104

Combining Social and Ecological Needs on Federal Lands: A

Global Perspective

Marlin Johnson

Author

Marlin Johnson is Assistant Director of Forestry, U.S. Department of Agriculture, Forest Service, Southwestern Region, 333 Broadway SE, Albuquerque, NM 87102.

Abstract

For the past few centuries the human elements of Earth’s ecosystems have not been in steady state;

growth has far exceeded loss. That growth has consumed ever-increasing amounts of land, water, energy,

crops, wood, and biodiversity. Sustainable forestry cannot stop at the forest border; it must encompass the

human enterprise as well. Increasing global consumption, along with the easy transportation and global

marketplace that has developed over the last 50-plus years causes demand on forest resources to be felt

throughout the world. Increasing affluence in the United States and other developed parts of the world

leads to high rates of individual consumption. In the past four decades, substantial areas of federal forestland have been “set-aside” through reservations for uses and values other than wood removal. The decline

in harvest on federal lands has led to an ecological change in these forests. Inventories have built up to

high, often unsustainable levels. Developing economically feasible and socially acceptable silvicultural

techniques to restore healthy forest ecosystems, through removal of smaller, understory trees, is the major

challenge we face in nearly 17 million hectares of federal forests. Actions are needed to supply the world’s

need for renewable forest resources. If applied judiciously to federal lands, these actions can make for

healthy, sustainable forests. Providing ecological diversity, producing more wood, using more wood (instead of nonrenewable resources), and application of scientific knowledge to forest management, are essential components of federal forest management. To be successful in improving the ecological health on a

global basis, we must look at each decision in a global context.

Keywords: Ecosystems, natural resource management, sustainability, global demand, consumption.

addressing the topic of forest sustainability must

include consideration of worldwide resource use

and demand, population growth, and relationships

between the human and nonhuman parts and processes of ecosystems to make sense of a very

complex, global context. This paper will also address some perspectives on key resource issues

facing the world today, and how these issues pertain to managing the National Forests.

The Forest Service ranks above the rest in ecosystem science. This is well documented in this report.

However, we must consider more than just ecosystem science to determine where, how, and for what

purpose we apply ecological knowledge. In order

to do “intelligent tinkering” as Aldo Leopold suggested, good science has to go well beyond the

environmental science we traditionally deal with to

cover the issues that pertain to managing the National Forests. While ecological, silvicultural, genetic, and wildlife management information are

Introduction

The Multiple-Use and Sustained Yield Act of 1960

mandated that the USDA Forest Service manage

the National Forests to provide sustained yields for

its natural resources. In the early 1990s, the Forest

Service adopted ecosystem management as a holistic approach to meet the mandate, as well as the

demands and preferences of the diverse publics.

Ecosystem management is defined as the use of

an ecological approach that blends the needs of

people and environmental values in such a way

that the National Forests and National Grasslands

sustain diverse, healthy, productive, and adaptable

ecosystems (Robertson, 1992).

This paper addresses some perspectives on the

evolving use and management of U.S. National

Forest lands, and their relationship to natural resource management issues in a global context.

While emphasizing federal forestlands in the U.S.,
105

needed for ecosystem management and sustainability, more is required if we are going to be prepared for a doubling in the population and the

related increase in consumption and use of our

forests. The following are themes on which this

concept was developed:

1. Global demand and consumption. All humans

use natural resources, some more than others.

We live in a global marketplace that satisfies

its demands from one resource or another, or

with resources from one place or another. The

global population passed six billion in 2000. It

has been estimated that population growth will

double again before leveling off late in this century. Even the most conservative estimates indicate a population of around eight billion by midcentury. Feeding, clothing, and sheltering six

billion people already consumes a high percentage of the world’s resources. Unless personal

habits of affluent cultures change, the impacts of

projected population growth on world resources

could be greater than just that reflected in the

increase in numbers of people. For example,

since 1970, the average family size in the United

States has dropped by 16 percent, while the size

of an average single-family house being built

has increased by 48 percent (USDC 1970-1997).

The use of paper has increased by 40 percent;

printed-paper and paper checks by 100 and

200 percent, respectively; and fax paper use

is also increasing. The following trends are expected during this period of population growth

in the United States:

• Relative stability in forest area.

• Fourteen percent increase in domestic timber

supply.

• Sixteen percent increase in housing starts.

• Increased demand for nonwood forest values

including recreation, water, wildlife and

wilderness.

• Increased biomass accumulation leading to

more fire and forest health problems.

• Annual wood consumption is projected to increase from 525 million cubic meters (about

18.5 billion cubic feet; one cubic meter equals

35.3 cubic feet) in 1991 to 710 million cubic

meters in 2040.

Between 1990 and 1997, timber harvest from U.S.

federal forestlands, which formerly supplied about

25 percent of U.S. softwood timber production,

declined from about 66 million cubic meters per

year to 24 million cubic meters (Draft 2000 RPA

Assessment). Because domestic demand for wood

products did not decline in similar fashion during

this period, this has caused a shift in tree harvest

to U.S. private lands and to Canadian forests. Between 1990 and 1997, U.S. softwood lumber imports from Canada rose from 42 to 63 million cubic

meters, increasing from 27 to 36 percent of U.S.

softwood lumber consumption (Howard 1997,

USTR 1996). Imports of panel products from

Canada increased as much as lumber. Much of this

increase in lumber imports has come from native

old-growth boreal forests of eastern Canada. In

Quebec alone, the export of lumber to the United

States has tripled since 1990 (MacCleery). This is

a prime example of the global transfer effects of

domestic resource policies that consider only supply and only one sector of the potential supply

source.

Due to the combined effects of world population

increase and land use conversion, the amount of

forestland available to each person has declined

globally by 50 percent since 1960, to 0.6 hectares

(about 1.5 acres). By 2025, projections indicate it

will drop by another one-third to 0.4 hectares. Each

U.S. citizen uses approximately 2.1 cubic meters of

wood per year and this value is relatively constant

over time. Annual consumption for the nation was

525 million cubic meters in 1991 and is projected

to rise to 710 million cubic meters by 2040. Our

net annual growth is 612 million cubic meters, so

today the United States could supply its own needs

without imports but would have to increase growth

or continue to increase imports to do so by midcentury.

Substituting nonrenewable resources as wood alternatives needs serious consideration. On a daily

average basis, each of the six billion people on

Earth consumes about 1.6 kilos of wood. Half of

that wood is used for energy by a segment of the

population that cannot afford gas or other energy

sources. What are some alternatives to wood use?

All known wood substitutes are more energy consumptive to produce and labor consumptive to use,

often by many times the cost. Steel, aluminum,

cement, and plastics, for example, are nonrenewable resources, but their consumption pollutes the

atmosphere with carbon dioxide. Wood alternatives
106

for paper includes fibers such as kenaf, hemp, and

cotton. All of these substitutes may suffice for wood

alternatives in the short term, but may not be better

for the environment on a long-term basis. Nonrenewable wood alternatives may have less impact

on the environment if they include, for example,

electricity generated from fossil fuels that move

tons of carbon from underground to the atmosphere. Transfer effects also need to be seriously

considered.

2. Global effects of local marketplace resource

decisions. The National Forests contain about

45 percent of the softwood lumber in the U.S.,

but supply only about one percent of the nation’s

needs. What are the global transfer effects of

obtaining the balance elsewhere? Was it good

science to stop harvesting on millions of acres of

timberlands in the U.S. in the last decade under

the auspices of protecting species, or to “protect

biodiversity” or preserve roadless conditions

where excessive fuel densities threaten to turn a

lightning strike into a catastrophic wildfire? Have

we done this in full consideration of the secondary effects? In North America, no species has

ever become extinct due to timber harvesting.

Growth on the National Forests (outside wilderness and other classified areas) is about 93 million cubic meters, yet we have decreased

removals from around 42 million cubic meters in

the late 1980s to less than 10 million cubic

meters in recent years. Have we adequately

considered the broad ecological effects, as well

as economic effects, of moving this amount of

harvest to other lands or of letting it accumulate

on-site?

In the Southwest, net annual growth on the National Forests is five million cubic meters, enough

solid wood to cover a football field to a depth of

about one mile. This would also provide enough

wood to build 95,000 homes of 1800 square feet.

each! In recent years we’ve only removed about

1/10 of the annual growth; however, our consumption has not declined. We have moved much of the

extraction of resources to other parts of the globe.

This is often called “NIMBYism,” referring to the

“not in my back yard” philosophy. Table 1 compares

growth to removal for the Interior West on National

Forests.

3. The role of wood removal in sustainable forestry and ecosystem health. Since the 1960s,

environmental laws have been legislated, each

with a specific objective to either allow for public

participation in land management, or to protect

a specific value. Since 1970, challenges to the

various environmental laws on a site-by-site

basis have resulted in sweeping changes in how
107

National Forest lands are managed. Former

Forest Service Chief Jack Ward Thomas (1996)

stated: “It has become increasingly obvious that

the overriding de facto policy for the management of Federal lands is the protection of

biodiversity. That de facto policy has simply

evolved through the interaction of laws, regulations, court cases, and expedient administrative

direction. This de facto policy, I believe, is the

very crux of the raging debate over the levels of

commodity production that can be expected from

Federal lands.”

Without a national debate on this issue, resource

outputs, such as wood products, have become byproducts of lands managed for other purposes.

Some environmental interest groups are now promoting a total logging ban on National Forests.

However, timber harvest is a major tool for reducing

stand density, and recent estimates indicate that

there are more than 16 million hectares of western

U.S. forestlands seriously overstocked, mostly with

small trees.

In much of the world, over-harvesting and conversion to non-forest land uses are the most serious

threats to forest sustainability. Over the last several

decades, many National Forest lands in the U.S.

have become seriously overstocked due to reduced natural fire levels and “under-harvesting.”

The concept of “under-harvesting” as a problem is

relatively new, and it is primarily a concern in shortfire-interval ecosystems where removal of this biomass by fire and decomposition has been interrupted. In these areas the risk of catastrophic

disturbance and associated losses are grave. In

many Interior West forests, precipitation has been

above the long-term average for three decades, exacerbating the imbalance between forest growth

and biomass removals. Some meteorologists are

predicting a change to much dryer conditions; however, a major concern is that dryer conditions will

lead to wildfire losses beyond tolerance, from

which ecosystem recovery will be difficult, costly or

both. To this end, the Forest Service is designing

activities to restore more natural biomass density

and biological diversity in these forests.

In some cases, with change from production forestry to restoration forestry, we still find a substantial yield of wood products. If wood is not removed

from the land mechanically or by natural processes, such as cool ground fires, it will build up to

levels that lead to catastrophic levels of fire, insects or disease.

Contrary to the Organic Act, Multiple-Use Sustained Yield Act, and the National Forest Management Act, many would have society believe that the

National Forests have no significant role in supplying wood to meet societal needs. Yet, many believe

that the National Forests still have a significant role

in providing wood in an environmentally sound

manner. Harvesting, for example, is a tool that can

be used to move forests toward the desired future

conditions of health and sustainability, as well as

provide needed resources and jobs for society. The

amount of wood removed may vary greatly depending on the forest ecosystem and also the effects of

past management activities.

Shifting the Paradigm

Fewer actions can be taken to remedy problems

and reach a more sustainable global environment.

Obviously, some actions are within our control as

resource managers, while others require society at

large to be involved. Some key opportunities that

have benefits are as follows:

1. Provide diversity. Avoid cookie-cutter prescriptions. Thinning from below, for example,

will accomplish one goal; it will reduce fire hazards. However, such a prescription will create a

new monoculture and depose natural diversity.

U.S. southwestern forests are so far out of their

natural balance that we need not worry about

prolonged and extensive restoration treatments, as long as we provide a variety of conditions.

2. Produce more wood. Forests are self-renewable ecosystems. They produce more wood,

more biodiversity, more wildlife, and other more

renewable products. If forests can renew themselves from total annihilation by glaciers and

volcanic eruptions, just think how much more

they can produce with our growing knowledge

of forest science, silviculture, biodiversity conservation, soils, and genetics. While providing

a renewable source of raw materials using

clean solar energy, they will also provide an

abundant supply of habitat for the thousands of

other species that depend on the forest for

their survival.
108

3. Use more wood. The “use less wood” policy is

anti-environmental because it would result in

increased carbon dioxide emissions and reduce the rate at which “non-productive” private

forests are converted to other uses. From an

environmental perspective, the more appropriate policy is “grow more trees and use more

wood.” In other words, use wood responsibly

instead of using nonrenewable resources.

4. Understanding the role of science in

decisionmaking. In 1996, Jack Ward Thomas

stated: “There is not a ‘science solution’ to

today’s problems. The sciences merely are a

tool. All managerial decisions are moral, not

technical. Science won’t give you ‘the answer.’”

5. Apply scientific knowledge to managing

forests and decisionmaking. Forest ecosystems are complex, but our current legal/social

situation is even more complex. There seems

to be little connection between scientific knowledge of forest ecosystems and many of the

decisions being made through the courts. The

power to make decisions on managing forests

has been taken from the majority (voters) and

placed in the hands of a few. Those who have

taken control are using the courts and various

laws, particularly the Endangered Species Act,

as tools to advance their agendas.

Conclusion

In summary, the National Forests are dynamic ecosystems, yet they face many challenges in the 21st

century. Ecological, economic and political sustainability, forest products, forest health, biodiversity,

endangered species, late-successional forests,

lifestyles, accountability, public participation, trust,

and increasing demand and consumption are foremost among these. In addition, they do not maintain a “steady state” balance, but over the longterm, growth and loss will stabilize.

The goal of ecosystem management is

sustainability—from individual sites to the global

biosphere. Given the immense consumption of

natural resources by a world population of 6 billion

and growing, and given the impacts of wood substitutes on the Earth’s ecosystems, using available

wood resources to restore desired conditions,

might be a prudent strategy to achieve the goal of

sustainability. Whatever the course, reducing the

overall impact of the human enterprise on the

Earth’s ecosystems will be a necessary component

of sustainable forestry.

Acknowledgements

Much of this paper is taken from an August 2000,

paper given at the IUFRO Conference in Malaysia.

The paper was entitled: The Role of Wood Removals in Sustainable Forest Management in

the United States: The Contribution of Federal

Lands. The authors were Marlin Johnson, Dr. Hal

Salwasser, and Barry Bollenbacher. Thanks go to

Debra Allen-Reid for both technical review and

editorial assistance.

References

Howard, J.L. 1997. U.S. timber production, trade,

consumption, and price statistics 1965-1994.

Gen. Tech. Rep. FPL-GTR-98. Madison, WI:

U.S. Department of Agriculture, Forest Service,

Forest Products Laboratory. 75 p.

MacCleery, D. [In press]. The U.S. experience in

managing federal forest lands: Are there some

lessons for Canada? Frederickton, New

Brunswick: Sylvicon 2000.

Robertson, D. 1992. Official correspondence. Ecosystem management of the national forests and

grasslands. File code 1330-1.

Thomas, J.W. 1996. The U.S. Forest

Service–What Now? Missoula, MT: University

of Montana.

U.S. Department of Agriculture, Forest Service.

[In press]. The Forest Service program for forest and rangeland resources: a long-term strategic plan.

U.S. Department of Commerce, Bureau of the

Census. 1970-1997. Characteristics of new

housing: current construction reports. Series

C25. Compilation of 1970-97 C25 reports.

Washington, DC.

U.S. Trade Representative. 1996. U.S. and

Canada reach agreement on softwood lumber.

Press Release, February 16, 1996. Washington,

DC: Executive Office of the President.
109

Summary
110

The Future of Silviculture Research—Thoughts from the Yale

Forestry Forum

Sharon T. Friedman and James M. Guldin

Authors

Sharon T. Friedman is national program leader for silviculture, Vegetation Management and Protection

Research, P.O. Box 96090, Washington, DC 20090; and James M. Guldin is a research forest ecologist

and project leader, Southern Research Station, University of Arkansas at Monticello, P.O. Box 3516,

Monticello, AR 71656.

Abstract

The 1999 Yale Forestry Forum, sponsored by Yale University and the USDA Forest Service, brought together a number of experts in an academic setting to discuss the future of silviculture research in the next

century. Four participants in the plenary session outlined three areas that will characterize the future of

silviculture research—sustainability, flexibility, and rigor. Sustainability includes two elements—sustainability of practices at different scales of management, and striking the appropriate balance of conditions

across the landscape. Flexibility has three elements—feasible ‘silvicultural pathways’ for species of interest, research within and among a wide scale of intensities of management, and silviculture for a variety of

‘at risk’ situations. Rigor has two elements—silviculture research as a subset of a larger array of response

variables, and maintenance of high standards of statistical design for silvicultural research. The implications of these and other elements raised for future funding of silviculture research remains unclear, but

will give the silviculture research community an opportunity for enhanced discussion of priorities in the

immediate future.

This paper presents highlights and key concepts

from the session. It should not be considered to

represent the views of the USDA Forest Service,

or of the Yale School of Forestry and Environmental Studies. Rather, the ideas brought forward here

represent the authors’ view of the concepts and

priorities for silviculture research based on comments of the forum participants during both the

plenary session and the roundtable discussion.

Nor should these ideas be considered as the ultimate contribution on the subject. The virtue of hindsight, enabled by a review of transcripts of the

session, and the opportunity to consider perspectives and input from other experts not available to

those at the meeting, can lead to the introduction

of new ideas or the heightened awareness of others raised but not dissected in detail at the Yale

Forestry Forum. These will, and should, also contribute to the larger discussion as well.

Thus, rather than the final word, this paper should

be viewed as the beginning of a larger discussion

among the profession about the future of silviculture research. The authors hope that this work can

promote that larger discussion in a number of appropriate venues, including this 2001 National Silviculture Workshop.

Introduction

In October 1999, staff from the Office of the Deputy

Chief for Research of the USDA Forest Service

collaborated with faculty and professional staff from

the School of Forestry and Environmental Studies

at Yale University to exchange ideas on the future

of silviculture research (Wishnie et al. 2000). Organized under the auspices of the Yale Forestry

Forum, the program was highlighted by a plenary

session in which invited experts from government,

industry, academia, and a non-government organization presented views from each perspective on

the prospects for silviculture in the next century,

and the research that would be needed to support

those prospects. Following the plenary session, a

roundtable discussion was held that featured the

invited experts as well as a number of other active

and respected silviculturists from academia, government, and the private sector. Adding to the

value of that discussion was the participation of the

graduate student body at Yale and the College of

Environmental Sciences and Forestry from the

State University of New York at Syracuse.
111

Methods

Organizers of the Yale Forestry Forum invited four

keynote speakers to kick off the symposium, and

arranged for the participation of a dozen other

practicing research and academic silviculturists.

Most, but not all, in attendance were from institutions—Yale and others, and the Northeastern

Research Station of the USDA Forest Service—

located in the northeastern part of the country.

The Forestry Forum was organized in two sessions—a plenary session and a roundtable discussion. The Plenary Session was conducted as four

half-hour presentations, followed by a general

question and answer period. Participants in the

Plenary Session were:

1) Dr. Greg Aplet, Research Ecologist, The Wilderness Society, Washington DC;

2) Dr. Chadwick D. Oliver, Professor of Forestry,

School of Forest Resources, University of

Washington, Seattle WA;

3) Dr. Susan Stout, Research Forester and

Project Leader, Warren Forestry Sciences

Laboratory, Northeastern Research Station,

USDA Forest Service, Warren, PA; and

4) Dr. John Hodges, Woodlands Manager,

Anderson-Tully Company, Memphis TN,

(former faculty member, Department of

Forestry, Mississippi State University,

Starkville, MS).

The Roundtable Discussion included these experts

and others. Opportunities for extended input were

given to a half-dozen other prominent academic

and agency research silviculturists, and to several

practitioners attending the forum. Finally, a round

of opportunities for comments were taken from the

floor, and prominent among these were what might

literally epitomize the future of silviculture research—members of the Yale graduate student

body. Thus, the discussion pool included largely

individuals from one region of the country, and

largely one philosophical perspective—virtually

everyone at the meeting would not hesitate to

conduct active interventions in a stand should conditions so warrant. Results from the discussion

should be interpreted from this perspective.

Both sessions were taped, but with different formats. The plenary session was videotaped. This

offered good opportunities to review speakers’

overheads, provided that they were of sufficient

clarity and resolution to review on the VHS format.

The roundtable discussions were taped by using

cassette audio tapes. This provided a few different

problems in review. Not all speakers identified

themselves or were known to the reviewers of the

tape; others spoke too softly, or were seated too far

from the microphone to allow their comments to be

clearly heard. By and large, however, the authors

think that these comments allowed for a reasonably

complete capturing of the comments raised by the

Forum’s many participants.

In such circumstances, the challenge to the authors

was not too little material, but too much. The challenge of this review-through-media format is to

collect, organize, synthesize, and evaluate the

material raised by those attending the Forum. Any

shortcomings in interpretation or omission of comments are to be blamed on the authors.

Results

Plenary Session

A number of major comments arose from the comments of the four speakers at the plenary session.

These were centered in three key areas:

sustainability, flexibility, and rigor. Specific comments can be broken down into eight key areas:

Sustainability

Sustainability of practices at different scales of

management. The definition of sustainability at the

stand and landscape scale is not clear in existing

silvicultural literature. Nor is the contribution that

silviculture can make a clear one to understand.

Delinking the public’s assumption that silviculture

is synonymous with timber production is a key

element.

Striking the appropriate balance of conditions

across the landscape. Several speakers pointed

to the need for more thought and research to the

dynamic distribution of conditions across the landscape, and the silvicultural contributions to that

balance. A strong analysis and discussion of the

intensive plantations, reserves, integrated management approaches from the financial, social, and

economic perspectives is needed and has yet to

occur.
112

Flexibility

Feasible ‘silvicultural pathways’ for species of

interest—Despite some seven decades of productive research on specific species, many species of

interest to land managers are underrepresented in

the scientific literature. This is especially the case

when considering reproduction cutting methods

such as the shelterwood and single-tree selection,

or intermediate treatments such as the use of prescribed fire. Learning more about applying a wider

variety of silvicultural treatments to a wider variety

of situations is a high priority.

Research within, and increasingly among, a

wide scale of intensities of management—While

plenary session speakers disagreed about the details of this key area, there is support for continued

research in intensive management among industry

clients and expanded research in natural stand

management.

Silviculture for a variety of ‘at risk’ situations—

Enhanced understanding of how silvicultural practices can be used for hazard reduction (acute, such

as pestilence, or chronic, such as extensive herbivory or buildup of fuels near areas that require

fire protection). Techniques for restoration of plant

communities underrepresented on the landscape

(such as longleaf-wiregrass restoration, restoration

in the lower southeastern Coastal Plain or shortleaf

pine-bluestem restoration in the Interior Highlands)

would also be of interest. Especially valued would

be an understanding and acceptance that silvicultural manipulations can be applied in specific instances to improve habitat of endangered,

threatened, and sensitive species. There are instances in the literature where this has been documented.

Rigor

Increasing understanding the context for and

variety of responses to silvicultural manipulation—More and more, participants held the view

that silviculture of the next century would not remain viable in the absence of experiments that

embrace a broader variety of response variables.

The professional interactions that result when silvicultural research is conducted in juxtaposition with

wildlife, social science, economics, and other disciplines adds not only to the studies themselves but

also to the perspective of silviculturists.

Maintenance of high standards of statistical

design for silvicultural research—Finally, plenary

session participants were of the opinion that rigorous experiments should be the norm rather than

the exception. It is critical that new experiments be

subject to statistical evaluation before installation.

The difficulty in this challenge is to capture appropriate degrees of experimental error by using appropriate statistical designs as spatial and temporal

scales increase.

Roundtable Discussions

A number of points were raised in the discussion

session that differed from the concepts raised in

the plenary session. In some cases, the discussion expanded considerably on the main elements

initially raised in the plenary session. In others,

new elements were introduced. The main elements

follow:

Cohesion across ecogeographic boundaries—

Several participants commented on the potential

value of a common experimental design and data

structure in the context of silvicultural practices

research. For example, a new group selection

study might be developed using a common study

design and similar measurement protocols across a

variety of forest types. By comparing and contrasting results across forest types, scientists could

develop better conceptual models for group selection that clarify what elements of the prescription

apply for a specific forest type, and which elements

appear to hold across all forest types.

Enhanced understanding of social needs—

Some participants observed that the understanding

of silviculturists about society’s larger needs from

forests was limited at best. Few would disagree

that improvements in understanding the values of

society and the needs of society for forests in the

next century might be good information to have in

designing silvicultural experiments.

Technology transfer—Information about accepted

sound forest management practices was available

in the literature, but was not getting into the hands

of private landowners or forest managers. Periodically, foresters find themselves in conflict with their

peers not because either is wrong, but because

one has had the opportunity to learn something the

other one hasn’t. This seems to be an especially

persistent problem on private non-industrial lands

where exchange of information, both researchers to
113

practitioners and practitioners to practitioners, can

be limited. Moreover, some foresters cross the line

of accepted ethical application in withholding certain silvicultural recommendations from private

landowners if implementing those recommendations might reduce the fee the forester could collect. State extension offices, technology transfer

experts within the Forest Service, and professional

societies such as SAF should revisit the mechanisms needed to link research with the on-theground folks, the consultants, the field foresters for

industry and government agencies, and the state

service foresters. Research findings are of minimal

value unless they can be translated to application

in the woods.

Attentions to a broader spectrum of landowners, especially small-parcel NIPF

landowners—Landowners with small ownerships

on the order of 20-300 acres provide a particular

challenge for foresters, given the marginal operability for many silvicultural practices, and the marginal profitability for consulting foresters, on tracts

in this size. Many landowners don’t have the resources to pay for good silviculture or management

practices. To this end, ways should be identified to

make a quality job of vegetation management on

small parcels affordable to landowners. Understanding the development of these stands and possibilities of a range of benefits and costs from

manipulating that development is the key information that needs to be developed and transferred.

Silviculture for values other then timber—An

important transition for silviculturists is to increase

the breadth of silvicultural research beyond simply

timber growth and yield. The great bulk of landowners are not just going to produce timber, but are

very interested in what effects the production of

timber has on related resources. People’s values

don’t always mesh very well with the information

that silviculturists are trying to peddle—especially

smaller landowners and, increasingly, the general

population with respect to public lands. Moreover,

time has shown the weakness of the post-war

axiom that ‘good forestry for timber is good for

everything else.’

Silvicultural implications of the ‘range of natural

variability’ concept—From the research perspective, a focus on silviculture as applied stand behavior and ecology rather than as a tool for production

of timber or creation of habitat for a single endangered species may carry greater flexibility to meet

uncertain future resource issues. Studies developed broadly in the context of ecological fundamentals rather than the question of the day will

have a better chance of producing relevant research over time.

Role of traditional production research— A

small but important component of the forest land

ownership base—forest industry—will continue to

emphasize research on intensive silviculture. This

is especially the case in making refinements in

development of genetically improved planting stock

(such as for enhanced physiological uniformity or

resistance to herbicides), improvements in strategy

and tactics of chemical silviculture (“weed and

feed” mixtures of herbicides and fertilizers, or increased precision in application rates depending

on seedling or sapling attributes within a stand),

and tailoring of silvicultural practices to anticipated

products. Finally, companies are discovering that

fewer people in the woods leads to fewer liability

issues, but the challenge of maintaining rates of

production with fewer workers will lead to continued

research on the operations side of silviculture.

Economic interpretations of silvicultural experiments—Many silviculturists lack extensive training

in financial analysis, but added value would immediately result from application of economic and

financial analyses to silvicultural studies. For example, many long-term, large-scale habitat studies

lack this component, and as a result, it can be difficult to convince landowners of the costs and benefits of silvicultural practices. Information on the

financial aspects of management is critical when

translating research results using language to

which landowners, especially NIPF landowners,

can relate. And this can, in most instances, be

done with very little additional effort, but should be

incorporated into the planning of the work.

Discussion

This document represents the first step to capture

the thoughts and opinions of scientists and practitioners of silviculture regarding the future of their

field. A broader review will be conducted through

staff members and field scientists in Forest Service

Research and Development to build upon some of

these issues, discount others, and raise new issues

not brought forth to date.
114

The panelists and roundtable participants consistently held that silviculture must increasingly encompass a greater diversity of treatments, larger

scales, longer timeframes, more disciplines, and

more landowners. There is clearly a role for traditional production research, especially in the hightechnology arena of tree breeding for resistance

to herbicides, insects, and pathogens, but there’s

a corresponding interest in applying silviculture in

the context of restoration of natural systems. And,

clearly, more attention must be given to the distribution of research products—through technology

transfer and to clients that have not been reached

by using the extension tools of the past few

decades.

For scientists, the challenge will be in implementing

these changes; for research administrators, the

challenge will be in development of the support

infrastructure to support their implementation. It

may be that different organizational pathways and

research work unit structures must be developed

to implement and fund these changes. But the general tenor of discussion is clear—silviculture is not

just for timber management any more, if it ever

was.

Reference

Wishnie, M.; Ashton, M.; Friedman, S.T. [and

others]. 2000. The future of silviculture and

applied ecology research—a summary of a

forum exploring the evolving role of silviculture

and silviculturists in the United States. Yale

Forest Forum Series Volume 3, Number 2. New

Haven, CT: Yale School of Forestry and Environmental Studies. 40 p.
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