Managing for Wildlife

Habitat in Westside 

Production Forests

United States 

Department of 

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical

Report

PNW-GTR-695

February 2007
TECHNICAL EDITORS

Timothy B. Harrington, research forester, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research

Station, Forestry Sciences Laboratory, 3625 93rd Ave. SW, Olympia, WA 98512 and Gretchen E. Nicholas, division manager,

Washington State Department of Natural Resources, 1111 Washington St SE, Olympia, WA 98504.

Cover photography courtesy of Timothy B. Harrington (top left and bottom left), John P. Hayes (top right), Port Blakely Tree

Farms LP (middle), and Washington State Department of Natural Resources (bottom right).

Graphic designer: Jenny Beranek, Beaverton, OR.

Papers were provided by the authors in camera-ready form for printing. Authors 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 is for information only and does not imply endorsement by the U.S. Department of Agriculture

of any product or service.

PESTICIDE PRECAUTIONARY STATEMENT

This publication reports research involving pesticides. It does not contain recommendations for their use, 

nor does it imply that the uses discussed here have been registered. All uses of pesticides must be registered 

by appropriate state or federal agencies, or both, before they can be recommended. 

CAUTION: Pesticides can be injurious to humans, domestic and wild animals, and desirable plants if they are not

handled or applied properly. Use all pesticides selectively and carefully. Follow recommended practices for the

disposal of surplus pesticides and pesticide containers.
Managing for

Wildlife Habitat 

in Westside 

Production 

Forests

Timothy B. Harrington 

and Gretchen E. Nicholas, 

Technical Editors

U.S. Department of Agriculture

Forest Service

Pacific Northwest Research Station

Portland, Oregon

General Technical Report

PNW-GTR-695

February 2007
This page is intentionally left blank.
ABSTRACT

Harrington, Timothy B.; Nicholas, Gretchen E., tech. eds. 2007. Managing for wildlife habitat in Westside 

production forests. Gen. Tech. Rep. PNW-GTR-695. Portland, OR: U.S. Department of Agriculture, Forest

Service, Pacific Northwest Research Station. 135 p.

On October 18, 2006, a workshop was held in Vancouver, WA, with the title “Managing for wildlife habitat

in Westside production forests.” The purpose of the workshop was to provide prescriptions and guidelines for

people who manage Westside forests (those west of the Cascade Mountains’ crest) primarily for wood production, but because of mandate or personal preference, want to integrate wildlife values. The audience included

over 150 professionals from forest industry, consulting firms, and public and tribal forest and wildlife management agencies. This proceedings includes ten papers based on oral presentations at the workshop plus a synthesis paper summarizing workshop themes, discussions, and related information. Topics include a history of

wildlife management research in the Pacific Northwest, elements of habitat and how to manage for them, the

challenges of appropriately implementing ecosystem management, and economic implications to private forestland owners.

KEYWORDS: Wildlife habitat, old-forest structure, thinning, coarse woody debris, wildlife trees, management

regimes, economic analysis.
ACKNOWLEDGMENTS

This workshop was sponsored by USDA Forest Service, Pacific Northwest Research Station; Washington 

State Department of Natural Resources; Southwest Washington Chapter, Society of American Foresters; and

Western Forestry and Conservation Association. Special thanks to Gary Benson for his helpful suggestions for

the proceedings, Grace Douglass for manuscript formatting and editing, Cassandra Koerner for proofreading,

and Richard Zabel for orchestrating the workshop.
Managing for Wildlife Habitat in Westside Production Forests.

CONTENTS

KEYNOTE PRESENTATIONS

Changing Perceptions of the Role of Managed Forests as Wildlife Habitat in the Pacific Northwest 3

Keith B. Aubry

Forest Ecosystem Management: Miracle or Mirage? 19

J.P. (Hamish) Kimmins

SILVICULTURAL APPLICATIONS

Key Elements of Stand Structure for Wildlife in Production Forests West of the Cascade Mountains 35

Joan C. Hagar

Silvicultural Guidelines for Creating and Managing Wildlife Habitat in Westside Production Forests 49

Timothy B. Harrington and John C. Tappeiner II

Wildlife Habitat Management Practices on Private Non-Industrial Forestlands 61

Jim Bottorff

ECONOMIC CONSIDERATIONS

Combining Management Goals of Wildlife Habitat Conservation and Revenue on Washington 

State Trusts 67

Angus Brodie, Michael Bowering, Weikko Jaross, Don Reimer and Bryan Lu

Issues and Alternatives Associated with Private Forest Wildlife and Riparian Habitat Management 81

Bruce Lippke, Kevin W. Zobrist, and Kevin Ceder

Economic Considerations in Managing for Older-Forest Structure 95

Greg Latta and Claire A. Montgomery

INTENSIVELY-MANAGED FORESTS

Managing for Wildlife Habitat in Intensively-Managed Forests 107

Ken L. Risenhoover and S. Blake Murden

Proactive Management Considerations for Wildlife Habitat to Ensure Profitability 117

Malcolm R. Dick, Jr.

WORKSHOP SYNTHESIS

Managing for Wildlife Habitat in Westside Production Forests: A Workshop Synthesis 123

Pete Holmberg

Metric Equivalents 135
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KEYNOTE

PRESENTATIONS
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1 Keith B. Aubry is a Research Wildlife Biologist, USDA Forest Service, Pacific Northwest Research Station, 3625 93rd Ave. SW, Olympia, WA 98512

Managing for Wildlife Habitat in Westside Production Forests

CHANGING PERCEPTIONS OF THE ROLE 

OF MANAGED FORESTS AS WILDLIFE HABITAT

IN THE PACIFIC NORTHWEST

Keith B. Aubry1

INTRODUCTION

Coniferous forests play an important role in the economic health, social values, and biodiversity of the Pacific

Northwest. Environmental conditions in this region create

extensive forests with very large trees and unusually diverse

wildlife communities that include many rare and endemic

species. Although the states of Washington and Oregon

contain only 4.6% of the land and 6.8% of the conifer forests in the U.S., they contain 25.7% of the softwood timber

volume, 37% of the bird species, and 42% of the mammal

species (Bunnell and Kremsater 1990). During the late

1980s and early 1990s, conflicts among environmental

groups, the timber industry, and federal land management

agencies over the population status and habitat requirements of the northern spotted owl (Strix occidentalis 

caurina) and the fate of old-growth forests on federal lands

in the Pacific Northwest resulted in profound changes in

forest management objectives and the perceived role of

ABSTRACT

Forest management objectives and the perceived role of managed forests as wildlife habitat in the Pacific Northwest

changed in many significant ways during the 20th century. Before 1900, wildlife was generally considered something to be

exploited or exterminated, not managed or protected. This perspective began to change in the early 1900s when Theodore

Roosevelt promoted the doctrine of “conservation through wise use,” and Aldo Leopold established the science and practice

of wildlife management with the publication of his seminal textbook, Game Management. However, the most revolutionary

changes in public and professional perceptions regarding forest management for wildlife objectives occurred in the latter

part of the 20th century. Many of these changes began during the 1970s, after the environmental movement of the 1960s

resulted in the enactment of federal legislation designed to minimize environmental degradation, perpetuate biological

diversity, and protect endangered species. In this paper, I argue that changing perceptions about the role of managed forests

as wildlife habitat were associated primarily with the following four key conceptual turning points that were strongly influenced by these legislative mandates and the ground-breaking research and landmark publications of various scientists and

resource professionals in this region: (1) for which species should forests be managed? (2) at what spatial or ecological

scales should forests be managed? (3) which riparian zones should be managed? (4) can old-growth attributes be created 

in managed forests?

KEYWORDS: Forest management, landscape, old growth, riparian, wildlife.

3

managed forests as wildlife habitat (Thomas et al. 1991,

FEMAT 1993, Tuchmann et al. 1996). However, the evolution of both public and professional perceptions regarding

wildlife in managed forests that accompanied and sometimes directed those changes had its roots in the first

decade of the 20th century and continues today. My objective in this paper is to describe that evolution and demonstrate that it was associated with a series of key conceptual

turning points that were often initiated or strongly influenced by the ground-breaking research and landmark publications of various scientists and resource professionals in

this region. 

Wildlife Management Before 1900

Public perceptions and values associated with wildlife

changed dramatically in the United States during the 20th

century. Before 1900, wildlife was considered by most people as something to be exploited or exterminated, not managed or protected. Additionally, at that time, the concept of
“wildlife” was much narrower in scope than it is today, and

was limited primarily to the relatively large game birds and

mammals that provided food and sport; birds that provided

feathers for the millenary trade; furbearers that provided

pelts for coats, hats, and other fashion accessories; and

large predators that needed to be controlled or exterminated to protect people, livestock, and game. At that time,

hunting regulations were designed primarily to divide up 

a dwindling natural resource among the citizenry for as

long as possible (Leopold 1933). 

Providing the general public with access to game was

a uniquely American concept that differed fundamentally

from the European tradition of restricting the hunting of

game to landowners and other aristocrats. One of the reasons that wildlife management and protection took several

centuries to become established in the United States was

the common perception that the consumption of wildlife

resources was an inalienable right of every citizen. Before

the enactment of federal laws during the 20th century to

protect wildlife, increased law enforcement of “game hogs”

and the prohibition of “market hunting” for food and feathers were considered the best ways to maintain game populations and provide hunting opportunities to everyone.

Despite such protective measures, wildlife populations 

continued to decrease and some species, including the

bison (Bos bison), sea otter (Enhydra lutris), ivory-billed

woodpecker (Campephilus principalis), Carolina parakeet

(Conuropsis carolinensis), Eskimo curlew (Numenius

boralis), and passenger pigeon (Ectopistes migratorius)

were extirpated in the contiguous U.S. during the first half

of the 20th century (Matthiessen 1959). The bison and the

passenger pigeon, each of which occurred in astounding

abundance historically, were only the most dramatic examples of the catastrophic effects that unrestrained exploitation could have on wildlife populations.

Theodore Roosevelt - “Conservation through Wise Use”

The conceptual foundation for the science and practice

of wildlife management in America was laid by President

Theodore Roosevelt (fig. 1) in the first decade of the 20th

century (Leopold 1933). Roosevelt promoted the doctrine

of “conservation through wise use,” which asserted that

wildlife, forests, ranges, and waterpower were renewable

natural resources that could last forever if they were harvested scientifically, and not faster than they could replenish themselves. This concept influenced the subsequent

history of wildlife management in America in three important ways: (1) it recognized human use of all natural

resources as an integrated whole; (2) it established the 

conservation of natural resources as a public responsibility,

and private ownership of resources as a public trust; and

(3) it promoted science as the primary tool for meeting that

responsibility. In 1909, Roosevelt argued that the best and

most democratic approach to game protection would be

through a system of public preserves with protected breeding grounds, and laws established to define the conditions

under which the public could enjoy the privilege of hunting

(Leopold 1933). Roosevelt’s philosophy and activism for

wildlife permanently changed American attitudes toward

game and other wildlife, and created a new kind of naturalist who believed that the conquest of nature by human

activities carried with it a moral responsibility to preserve

and protect threatened species. 

Aldo Leopold - Managing Forests for Wildlife

The scientific discipline known today as “wildlife

management”, “wildlife biology”, or similar derivations,

was established almost single-handedly by Aldo Leopold

(fig. 2) in 1933 with the publication of his seminal textbook entitled Game Management (Leopold 1933). Prior to

the publication of this book, the management of wildlife

primarily involved hunting restrictions, predator control,

wildlife refuges, and game farming. Leopold was convinced that the best way to protect and perpetuate game

was to manage habitat conditions (especially forests) in

ways that would produce sustainable populations for hunting. The expansion of this discipline to include non-consumptive uses and other species of wildlife, including

non-game birds and mammals, amphibians, and reptiles

would come later. Leopold’s ideas were strongly influenced

4

Figure 1—Theodore Roosevelt.
by his formal training in forestry; he viewed game populations much the same way that foresters viewed trees or

farmers viewed crops; game was just a secondary crop that

foresters or farmers could produce by modifying their

methods of cultivating the primary crop (Leopold 1931).

He recognized that “the hope of the future lies not in curbing the influence of human occupancy—it is already too

late for that—but in creating a better understanding of the

extent of that influence and a new ethic for its governance”

(Leopold 1933:21). 

Leopold (1933) believed that with scientific guidance,

land managers could increase game by manipulating the

composition and interspersion of habitat types on the land.

Moreover, in his view, foresters played a unique and critically important role in the science and practice of game

management (Leopold 1930, 1931). He argued that (1)

other than trees, game is the only land crop that is best produced by use of natural species in a natural environment by

low-cost, low-yield techniques; (2) both timber and game

yields were based on skill in guiding natural processes in

relatively small ways; (3) unlike zoologists, who still relied

largely on descriptive science, foresters had always used

quantitative methods that could be applied directly to game

management; and (4) forestry produces salable crops

needed by game, and game could furnish additional 

revenue needed for forestry (Leopold 1930). 

Leopold also played an instrumental role in the founding of The Wildlife Society and the establishment of the

Journal of Wildlife Management. He viewed game management as a specialized branch of applied ecology, not as a

sub-discipline of mammalogy or ornithology. At the annual

meeting of the Society of American Foresters in 1930,

Leopold advocated for the creation of a technical journal

modeled after the Journal of Forestry in which game management professionals could disseminate new scientific

knowledge and share experiences (Leopold 1931). In 1936,

a small group of biologists, including Leopold, formed

themselves into a temporary organization called the Society

of Wildlife Specialists. The following year, that group

became The Wildlife Society and published the first issue

of the Journal of Wildlife Management. Thus, by the late

1930s, many natural resource professionals possessed a

conservation ethic and recognized the importance of public

and private forests for perpetuating game species in America.

In addition, scientifically based tools for increasing game

populations by manipulating habitat conditions were being

developed and disseminated. However, both public and

professional perceptions of the role of managed forests as

wildlife habitat would change dramatically in many unforeseen ways during the latter part of the 20th century. 

KEY CONCEPTUAL TURNING POINTS

For Which Species Should Forests be Managed?

The inaugural issue of the Journal of Wildlife Management explicitly stated that wildlife management is not

restricted to game management; rather, it embraces the

practical ecology of all vertebrates and their plant and animal associates (Bennitt et al. 1937). However, such a comprehensive approach to wildlife management remained a

lofty ideal for most wildlife professionals until the 1970s.

The inclusion of species other than game birds and mammals in forest wildlife management began with the addition

of economically important, esthetically pleasing, or threatened birds and mammals from the 1940s through the 1960s;

all terrestrial vertebrates, including amphibians and reptiles, in the 1970s and 1980s; and finally, to all components

of biodiversity, including ecological functions, in the 1990s

and 2000s.

The initial broadening of wildlife management 

beyond game birds and mammals is exemplified by the

scope of Ira Gabrielson’s (1959) textbook entitled Wildlife

Conservation. Gabrielson was one of the leading wildlife

conservationists of his time; he wrote the first monograph

on the birds of Oregon (Gabrielson and Jewett 1940), was

the first Director of the U.S. Fish and Wildlife Service, and

later served as President of the Wildlife Management

Institute. Although the primary emphasis of his textbook

was on game and other economically important birds and

mammals, he also included chapters on migratory birds,

5

Figure 2—Aldo Leopold.
non-game birds and mammals, and rare and vanishing

species. However, small mammals are given only one page

of text; and amphibians, reptiles, and invertebrates are not

even mentioned. The chapter on relations between forestry

and wildlife is focused on game animals, sport fish, and

furbearers; consideration of other species is limited to brief

discussions of injurious rodents and seed-eating birds, 

and potentially beneficial insectivorous birds. Although

Gabrielson had spent many years observing and studying

the birds and mammals of Oregon, he believed that oldgrowth forests of the Pacific Northwest were biologically

depauperate (Gabrielson 1959:63-64); consequently, he

viewed clearcutting as generally beneficial to wildlife

because it opened the canopy and returned densely forested

areas to the early seral stages in which most forest game

birds and mammals thrived. He did not consider the potential detrimental effects of clearcutting or other forest practices on non-game wildlife or the complex ecological

relations of late-successional forests. 

The inclusion of all vertebrates in the discipline of

wildlife management began in the 1970s, driven primarily

by the enactment of three federal laws from 1970 to 1976

that mandated the maintenance of biological diversity in

public forests, and changed the science and practice of forest wildlife management in the Pacific Northwest in many

significant ways. The National Environmental Policy Act

of 1970 (NEPA) required all federal agencies to prepare an

Environmental Impact Statement (EIS) for public review

that evaluated the environmental consequences of proposed

development projects or programs, and included plans for

mitigating adverse environmental effects. The Endangered

Species Act of 1973 (ESA) required all federal agencies to

protect habitat critical to the survival and recovery of any

vertebrate, invertebrate, or plant species listed by the U.S.

Fish and Wildlife Service as threatened or endangered. 

The National Forest Management Act of 1976 (NFMA)

required the Forest Service to maintain viable populations

of all existing native and desirable non-native vertebrate

species on National Forest lands, to protect the resources

and habitats upon which vertebrate populations and endangered species depend, and to preserve and enhance biological diversity in each management area so that it is equal to

that of a natural, unmanaged forest (Stockwell 1990). 

The legal mandates and changes in public attitudes 

and values that were put in place or set in motion by the

enactment of these laws are what Jack Ward Thomas was

referring to in 1979 when he stated, “Until just a few years

ago, forest managers were not especially concerned with

wildlife. The law did not require it. The public did not

demand it. Politics did not compel it.” That statement

appears in the preface of a book that pioneered a revolutionary new approach to forest management for wildlife

objectives entitled Wildlife Habitats in Managed Forests:

the Blue Mountains of Oregon and Washington (fig. 3).

Thomas recognized that these new federal laws created

daunting new responsibilities to manage public and private

forests for wildlife, and that resource managers would need

new tools to meet those responsibilities. He also understood that they would be required to make important and

far-reaching management decisions regardless of the

amount of information that was available. 

Although most foresters and wildlife biologists understood that good timber management did not necessarily

equal good wildlife management, Thomas (1979) believed

that the effectiveness of forest management for wildlife

could be greatly enhanced if relevant scientific knowledge

and expert opinion (in the absence of that knowledge) 

were organized in a way that made sense both biologically

and silviculturally. Thus, Thomas organized the “Blue

Mountains” book according to habitat types or individual

structures that were relevant to forest managers (e.g., riparian zones, edges, snags, downed wood, etc.), rather than by

wildlife taxa, and explicitly considered silvicultural options

and impacts on wood production. Most importantly, he and

his colleagues devised a “matrix” approach to presenting

6

Figure 3—Cover of the book, Wildlife Habitats in

Managed Forests: the Blue Mountains of Oregon

and Washington (Thomas 1979).
information on wildlife-habitat relationships enabling 

managers to quickly and easily apply the best information

available to predict the potential effects of different forest

management activities on a comprehensive array of wildlife species, including reptiles and amphibians. Recognizing

the value and utility of this approach, Brown (1985) and

his colleagues produced a similar guide for wildlife management in coastal forests of the Pacific Northwest entitled

Management of Wildlife and Fish Habitats in Forests of

Western Oregon and Washington (fig. 4). Because of the

importance of fish resources and estuarine habitats in

coastal forests, Brown’s book also included a narrative

chapter on salmonids, and habitat-relationship matrices for

all freshwater fish and selected species of marine fish and

estuarine invertebrates. Although the information presented

in both books was focused primarily on vertebrates, these

important and influential works ushered in a more holistic

approach to forest wildlife management in the Pacific

Northwest that eventually included consideration of all

aspects of forest biodiversity.

Recently, the matrix approach for assessing the potential effects of forest management activities on wildlife 

was carried to its logical conclusion, both geographically

and ecologically, with the publication of Wildlife-Habitat

Relationships in Oregon and Washington (fig. 5) by

Johnson and O’Neill (2001) and their colleagues. This

monumental work covers all major terrestrial, freshwater,

and marine habitats in Oregon and Washington, and

includes an explicit consideration of salmon-wildlife relationships, and guidelines for identifying and prioritizing

areas and habitats for the conservation of biodiversity.

Another important improvement over the previous books

was the compilation of habitat-relationships matrices on 

an interactive CD-ROM. However, the publication’s most

unique and innovative contribution to the wildlife-habitat

relationships literature is the consideration of “key ecological functions” in a narrative chapter (Marcot and Vander

Heyden 2001) and in the matrices, based on the groundbreaking work of Bruce Marcot and his colleagues. With

this new tool, users could not only evaluate how wildlife

species would be affected by various management activities, they could also evaluate how those activities may

influence important ecological processes. Thus, although

the field of wildlife management was established in 1933

with the very narrow objective of providing sustainable

populations of game birds and mammals for sport hunting,

by the end of the 20th century it had evolved into the science and practice of managing forests to provide habitat for

all components of biodiversity (e.g., Bunnell and Johnson

1998; fig. 6) and to protect their ecological integrity. 

7

Figure 4—Cover of the book, Management of

Wildlife and Fish Habitats in Forests of Western

Oregon and Washington (Brown 1985).

Figure 5—Cover of the book, Wildlife-Habitat

Relationships in Oregon and Washington (Johnson

and O’Neill 2001).
At What Spatial or Ecological Scales Should Forests be

Managed?

The scale at which forest management for wildlife

objectives is applied also changed substantially during the

last decades of the 20th century. It began with a consideration of wildlife-habitat relationships at the scale of forest

stands or other relatively small and homogeneous habitat

patches, then broadened to include potential influences

occurring at the landscape scale, and eventually culminated in forest management planning in the context of entire

ecosystems. Leopold (1933) argued that the most important determinants of game abundance were the composition

and interspersion of habitat types required by each game

species (fig. 7). Although his recognition of the importance

of habitat heterogeneity reflects some of the rudimentary

aspects of landscape ecology, he did not consider potential

ecological or environmental influences occurring beyond

the home-range boundaries of individual game animals. 

The first explicit consideration of potential landscapescale influences on wildlife populations in managed forests

of the Pacific Northwest came in 1984 with the publication

of The Fragmented Forest by Larry Harris (fig. 8). In this

landmark book, Harris (1984) proposed applying the concepts of island biogeography (MacArthur and Wilson 1967)

to the management of forest landscapes, using forests of the

western Cascade Range in Oregon to evaluate the potential

effects of habitat fragmentation on wildlife. With the help

and support of Robert Ethington, Director of the Pacific

Northwest Research Station, and Dave Luman and Bill

Neitro of the Bureau of Land Management, Harris was

granted leave from the University of Florida and temporarily relocated to western Oregon to develop his ideas and

tap into the collective knowledge and experiences of local

forest ecologists, wildlife biologists, and resource managers.

Harris was one of the first ecologists to consider the

potential effects of habitat isolation on wildlife populations

in forested landscapes that contain relatively small, residual old-growth forest “islands” surrounded by a “sea” of

younger, managed forests. Harris’ ideas and his proposals

for mitigating detrimental landscape-scale influences on

sensitive wildlife species in managed forests were both

important and influential. The seminal textbook, Landscape

Ecology, by Richard Forman and Michael Godron (1986)

was published 2 years after Harris’ book and the journal,

Landscape Ecology, was inaugurated 3 years later in 1987.

It is noteworthy that the first article in the first issue of the

journal was “Creating landscape patterns by forest cutting:

ecological consequences and principles” by Jerry Franklin

and Richard Forman (1987). 

By the early 1990s, many natural resource professionals in the Pacific Northwest understood that management

directed only at the stand scale was comparable to looking

at only one small part of a painting or photograph. Both

researchers and managers were becoming increasingly

aware that important ecological processes operated at multiple spatial and temporal scales, and that the ecological

integrity of managed landscapes could be improved by

8

Figure 6—Cover of the book, Policy and

Practices for Biodiversity in Managed

Forests: The Living Dance (Bunnell and

Johnson 1998).

Figure 7—Illustration showing how different interspersions of the same total

area of habitat types used by quail results in different levels of abundance

(reproduced from Leopold 1933). 
modifying current forest management strategies based on

understandings gained from studying ecological processes

at larger spatial scales. Consequently, forest and wildlife

scientists began to address research questions at the landscape scale, and ecologists, forest managers, economists,

and social scientists began to consider how best to integrate

the concepts of landscape ecology into the science and art

of forest management. Many of the insights and findings

from research conducted in the Pacific Northwest were

summarized in the proceedings of a symposium convened

in 1999 to discuss landscape-scale management planning

entitled Views from the Ridge—Considerations for

Planning at the Landscape Scale (Gucinski et al. 2004; 

fig. 9). 

However, applying the concepts of landscape ecology

to forest management is extremely challenging. The development of new knowledge about landscape-scale influences on forest stands involves quantitative analyses of

complex interactions occurring among various attributes of

forest composition, structure, and function (Dale and Noon

2004). Conducting research at large spatial scales is further

constrained by the difficulty (or, some would argue, the

impossibility) of replicating experimental treatments at

landscape scales. Moreover, several studies have suggested

that landscape-scale influences on many species of wildlife

(especially those with small spatial requirements) appear to

be relatively weak and difficult to detect (Lehmkuhl et al.

1991, McGarigal and McComb 1995). For these reasons, 

I suspect we may never be able to predict landscape-scale

influences on wildlife populations to the extent that we

understand how to manage individual forest stands or

structures to benefit wildlife. Nevertheless, consideration 

of the potential ecological and environmental effects that

occur at multiple spatial scales, including landscapes, is

now an integral part of forest management planning in the

Pacific Northwest. 

Once scientists and managers began considering ecological processes operating at spatial scales beyond that 

of individual forest structures and stands, it was not long

before their frame of reference expanded to include entire

ecosystems; i.e., to evolve into the conceptual framework

of “ecosystem management.” Franklin (1997:21) described

the development of this new management strategy as a

“paradigm shift of massive proportions.” He defined ecosystem management as a paradigm for managing land that

involves a holistic view of both natural and human resources, and has sustainability as its central premise. Thus,

forest managers are now being asked to seek a sustainable

9

Figure 9—Cover of the book, Views from the

Ridge—Considerations for Planning at the

Landscape Scale (Gucinski et al. 2004).

Figure 8—Cover of the book, The

Fragmented Forest: Island Biogeography

Theory and the Preservation of Biotic

Diversity (Harris 1984).
balance between the long-term integrity of entire ecosystems and a broad array of other management objectives and

societal values. The Northwest Forest Plan (USDA and

USDI 1994; fig. 10), which is a comprehensive, long-term

strategy for managing all federal lands occupied by the

northern spotted owl in Washington and Oregon, still represents one of the best examples of ecosystem management

in practice. 

Which Riparian Zones Should be Managed?

Timber volumes in riparian areas can be substantial in

coastal forests of the Pacific Northwest; Anderson (1985)

estimated that a 100-m swath along streams occurring in

the Siskiyou National Forest of Oregon contained 2 million

board ft of harvestable timber. Thus, it is not surprising that

prior to the 1970s, riparian areas in the Pacific Northwest

were typically clearcut and roaded, particularly along nonfish-bearing streams (Anderson 1985). Because riparian

areas represent key components of forested ecosystems 

for wildlife in the Pacific Northwest (Thomas et al. 1979,

Oakley et al. 1985), concerns about the ecological impacts

of such practices led to increased protection of riparian

zones in both private and public forests during the 1970s

and 1980s. For example, the National Forest Management

Act of 1976 required that special management consideration be given within a minimum of 100 ft (30.5 m) on each

side of perennial streams (Kauffman 1988). The First North

American Riparian Symposium was held in 1985 (Johnson

et al. 1985), and in 1987, a symposium was convened at

the University of Washington that focused exclusively on

riparian wildlife and forestry interactions in the Pacific

Northwest. Its purpose was to present the current state of

scientific knowledge about riparian areas and their use by

wildlife, riparian management policies and practices on

both public and private timber lands, and the social and

economic impacts of riparian management. The proceedings of this symposium were published as a book entitled

Streamside Management: Riparian Wildlife and Forestry

Interactions (Raedeke 1988; fig. 11). 

Both Thomas’ (1979) and Brown’s (1985) wildlifehabitat books included narrative chapters on riparian zones

that discussed their special importance for wildlife in the

Pacific Northwest (Thomas et al. 1979, Oakley et al. 1985).

However, the delineation of riparian zones in coniferous

forests and associated management guidelines were limited

primarily to those occurring along lakes, ponds, rivers, and

perennial streams that supported distinctive riparian vegetation (i.e., sedges, rushes, shrubs, and deciduous trees).

Because both perennial and intermittent headwater creeks,

seeps, and small forested wetlands are often contained

within upland coniferous forests, and typically lack riparian

vegetation (especially in mesic Westside forests), they had

generally not been considered part of the riparian zone 

(fig. 12).

10

Figure 10—Cover of the Northwest Forest Plan

(USDA and USDI 1994). 

Figure 11—Cover of the book, Streamside

Management: Riparian Wildlife and Forestry

Interactions (Raedeke 1988).
In the late 1980s and early 1990s, the potential importance of a much broader array of riparian habitats for

wildlife began to be recognized. Corn and Bury’s (1989)

ground-breaking study on the effects of timber harvesting

on headwater habitats and stream amphibians in western

Oregon demonstrated the need to consider the entire complement of riparian areas in forest management planning,

including very small headwater streams and seeps. This

comprehensive view of riparian influences in coniferous

forests was integrated into forest management in the

Pacific Northwest with the publication of Forest Ecosystem Management: An Ecological, Economic, and Social

Assessment, commonly referred to as the “FEMAT Report”

(FEMAT 1993; fig. 13). The FEMAT team, led by Jack

Ward Thomas and Martin Raphael, evaluated the potential

effects of various ecosystem management alternatives on

both terrestrial and aquatic ecosystems within the range of

the northern spotted owl. For the first time, aquatic ecosystems were given equal consideration as terrestrial ecosystems in forest management planning. In addition, FEMAT

(1993) expanded the taxonomic scope of management 

considerations for riparian zone habitats to include mollusks, mosses, lichens, and vascular plants. This extremely

important and influential assessment established an effective process for ecosystem management planning that provided the empirical basis for standards and guidelines in

aquatic ecosystems in the Northwest Forest Plan (USDA

and USDI 1994), and substantially changed the management of riparian habitats in this region. 

Can Old-Growth Attributes be Created in Managed

Forests?

Perceptions about the ecological importance of oldgrowth coniferous forests in the Pacific Northwest changed

dramatically in the 1980s. Gabrielson’s (1959) view of the

value of old-growth forests for wildlife habitat and biological diversity provides a stunning example of the misconceptions some biologists had about the ecological importance of old-growth forests. He stated, “In remaining virgin

stands of spruce, fir, and redwood in the Pacific Northwest

...one may travel for miles without seeing any wildlife

except a few specialized birds and mammals... Biologists

have long recognized that an unbroken stand of mature 

forest is much nearer a biological desert than are the sandy

wastes of popular imagination.” (Gabrielson 1959:63-64).

Such perspectives ended in 1981 with the publication of

seminal research that Jerry Franklin and his colleagues

conducted in the central Cascade Range of Oregon entitled

Ecological Characteristics of Old-Growth Douglas-fir

Forests (Franklin et al. 1981; fig. 14). This slim volume

had a significant effect on the perceptions of both biologists

and managers about the unique characteristics and ecological importance of old-growth forests. These researchers

11

Figure 12—Depiction of the riparian zone in forested

habitats; note that headwater creeks extend outside the

riparian zone into forested habitats (reproduced from

Oakley et al. 1985). 

Figure 13—Cover of the Forest Ecosystem

Management Assessment Team (FEMAT) report

(FEMAT 1993). 
documented many important differences in species composition, ecological functions, and structural attributes of oldgrowth forests compared to both managed and unmanaged

(naturally regenerated) younger forests, based on empirical

evidence obtained in the field. They also speculated that

some old-growth characteristics could be created or maintained in managed forests by promoting the development 

of four key structural components: large live trees, large

snags, large logs on the ground, and large logs in streams

(Franklin et al. 1981). 

Their assessments of the importance of old-growth

Douglas-fir (Pseudotsuga menziesii) forests as wildlife

habitat were largely inferential in nature, however. Eric

Forsman’s pioneering research on the habitat relations of

the northern spotted owl in Oregon (Forsman et al. 1984)

had not yet been published, and the battle among environmental groups, the timber industry, and public land managers over the fate of spotted owls and old-growth forests

that would engulf the Pacific Northwest during the 1980s

(Ervin 1989, Thomas et al. 1990) had not yet begun.

Biologists still did not know if old-growth Douglas-fir

forests provided significantly different habitat for wildlife

than other stages of forest development, nor how many

wildlife or plant species might depend upon or find optimal

habitat in such forests. In 1982, in response to growing

concerns about the management of old-growth Douglas-fir

forests and to meet legal mandates of NFMA and related

regulations, the Forest Service chartered the Old-Growth

Forest Wildlife Habitat Research and Development Program

under the leadership of Leonard Ruggiero and Andrew

Carey. The objectives of this program were to (1) define

old-growth Douglas-fir forests for management purposes,

(2) identify wildlife species that are closely associated with

old-growth forests, and (3) determine the biological requirements and ecological relationships of closely associated

species (Ruggiero 1991). To address the second objective,

a large group of forest and wildlife ecologists implemented

a rigorously designed field study to characterize the wildlife and plant communities occurring in young (35-79

years), mature (80-195 years), and old-growth (>200 years)

age-classes of unmanaged, naturally regenerated, closedcanopy Douglas-fir forests in Washington, Oregon, and

northern California (Ruggiero et al. 1991a). 

The results of this unique and extremely ambitious 

program of research were presented at a major symposium

held in 1989 in Portland, Oregon that was attended by

almost 900 people, including reporters from several national news and scientific organizations. Two years later, the

final study results were published in the book Wildlife and

Vegetation of Unmanaged Douglas-fir Forests (Ruggiero 

et al. 1991a; fig. 15). The Pacific Northwest Research

Station described this landmark book as one of the most

important publications it has produced during the last 75

years (Duncan and Miner 2000). One of the key findings of

these studies was that relatively few plants or vertebrates

were significantly more abundant, or occurred exclusively,

in old-growth forests (Ruggiero et al. 1991b). Although

some old-growth characteristics, including the development

of massive tree crowns and buffered canopy microclimates,

were generally found only in old growth, other characteristics such as gaps, deeply shaded and cool understories, and

accumulations of woody debris on the forest floor were

also found to some degree in young and mature unmanaged forests (Spies and Franklin 1991). Similarities in the

wildlife communities occurring in naturally regenerated

young, mature, and old-growth forests were attributed to

the spatial and structural heterogeneity that is characteristic

of forests with complex disturbance histories, and to the

structural components (primarily large live trees, snags,

and logs) that had survived stand-replacing fires and were

“carried over” into the young, regenerating stand (Ruggiero

et al. 1991b). 

By the late 1980s, there were growing concerns among

many forest ecologists in the Pacific Northwest that forest

lands would be partitioned into two categories: (1) forests

that are managed primarily for timber production, and (2)

late-successional preserves that are protected from timber

harvesting (Franklin 1989, Thomas et al. 1990). Given that

12

Figure 14—Cover of the book, Ecological

Characteristics of Old-Growth Douglas-fir

Forests (Franklin et al. 1981).
most of the old-growth forests in this region had already

been harvested (Marcot et al. 1991), such an approach

would have resulted in the allocation of a large percentage

of forest lands into the first category, which many believed

would have a detrimental effect on regional biodiversity.

These concerns, combined with insights gained from the

research findings of the “Old-Growth Program” and other

ecological studies, led Jerry Franklin to suggest another

alternative that he called “New Forestry” (Franklin 1989).

He envisioned this new approach as a “kinder and gentler

forestry that better accommodates ecological values, while

allowing for the extraction of commodities”; i.e., the development of creative silvicultural approaches that focus on

the perpetuation of diverse forest ecosystems, not simply

on regenerating and growing trees. Important aspects of

this new silviculture included retaining structural legacies

during timber harvesting and designing timber sales to

minimize forest fragmentation. However, Franklin’s objective was not simply to propose a new set of management

prescriptions; rather, it was to stimulate current and future

generations of silviculturists and ecologists to begin thinking about how to manage forests and forest landscapes in

ways that would maintain resilient, diverse, and sustainable

forest ecosystems (Franklin 1989). 

Many of these alternative silvicultural approaches

were incorporated into the standards and guidelines for 

harvest units in the Northwest Forest Plan (USDA and

USDI 1994), including leaving or creating coarse woody

debris on the ground; retaining dispersed and aggregated

trees with an emphasis on the largest, oldest live, decadent,

or leaning trees and hard snags occurring in the unit; and

establishing riparian reserves along all riparian zones,

including intermittent streams and small wetlands. Innovative planting and thinning prescriptions have also been

proposed as a means of improving habitat conditions for

wildlife in managed forests by creating or accelerating the

development of late-successional characteristics. For example, Carey and Curtis (1996) proposed a “biodiversity 

pathway” for forest management that included planting of

Douglas-fir at wide spacing to provide for natural or artificial regeneration of other coniferous and deciduous tree

species, extended rotations (>80-130 yr) to enhance biodiversity and increase wildlife habitat quality at the landscape scale, and three different kinds of thinnings: (1) a

pre-commercial thinning to delay canopy closure and

increase diversity of understory and overstory vegetation,

(2) a heavy, variable-density commercial thinning to maintain tree growth and promote understory development, and

(3) subsequent variable-density thinnings to add coarse

woody debris to the ecosystem. Kohm and Franklin (1997)

brought together these and many other alternative approaches to managing forests for ecosystem sustainability 

in the book, Creating a Forestry for the 21st Century: The

Science of Ecosystem Management (fig. 16). This important

and wide-ranging book presented the current state of

13

Figure 15—Cover of the book, Wildlife and

Vegetation of Unmanaged Douglas-fir Forests

(Ruggiero et al. 1991a).

Figure 16—Cover of the book, Creating a Forestry

for the 21st Century: The Science of Ecosystem

Management (Kohm and Franklin 1997).
knowledge about the implementation of variable-retention

harvest systems, silvicultural practices for shaping stand

development to achieve multiple objectives, the role of

extended rotations, implications for forest genetics, and the

ecological roles of phytophagous insects, plant pathogens,

and mycorrhizal fungi in managed forests. 

CONCLUSIONS

Changes in the perceived role of managed forests as

wildlife habitat took place throughout most of the 20th century. However, the evolution of those perceptions started

slowly and changed in incremental and relatively insignificant ways until the environmental movement of the 1960s

resulted in federal legislation that permanently changed the

way forests are managed in the Pacific Northwest. Initially,

huntable wildlife was a useful secondary crop from plantation forestry; by the 1980s and 1990s, timber production

had become one of many competing objectives of forest

management that included maintaining or creating habitat

for a broad array of vertebrate and invertebrate wildlife.

Forest stands that are managed for wildlife objectives are

now being designed to include diverse conifer, hardwood,

and shrub species; a broad array of structural and ecological elements characteristic of old-growth forests; vertical

and horizontal heterogeneity; gaps and patches of intact

forest; and ameliorated microclimates, among others.

Forest management planning at the landscape scale now

includes consideration of stand composition, size, shape,

context, and connectivity, as well as the integrity of all

riparian zones occurring in the watershed. Lastly, management consideration is increasingly being focused on the

maintenance of biodiversity, ecosystem complexity, and

ecological functions. I suspect that the kinds of revolutionary changes in perceptions and management objectives I’ve

described here will diminish in the coming years; in many

ways, our course has been set. Future challenges will probably have less to do with determining what the objectives

of forest management should be than with determining 

how best to address ecosystem management objectives in

effective and sustainable ways. 

ACKNOWLEDGMENTS

I thank the organizers of the Managing for Wildlife

Habitat in Westside Production Forests workshop for inviting me to prepare this paper. Tim Harrington, Gretchen

Nicholas, Richard Miller, and Cathy Raley provided helpful comments on previous drafts of this manuscript. Much

of the history and information presented here reflects in

various ways my personal experiences working with forest

wildlife of the Pacific Northwest during the last 25 years.

Acccordingly, I have undoubtedly failed to include all of

the people and publications that made important contributions to the perceptual evolution I’ve described here. To

anyone who may feel slighted, please accept my apologies

and be assured that any such omission was unintentional. 

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

Service, Rocky Mountain Forest and Range

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Marcot, B.G.; Holthausen, R.S.; Teply, J.; Carrier, W.D. 

1991. Old-growth inventories: status, definitions, and

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tech. coords. 1991a. Wildlife and vegetation of

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E.C.; Noon, B.R.; Verner, J. 1990. A conservation 

strategy for the northern spotted owl: a report of the

Interagency Scientific Committee to Address the 

Conservation of the Northern Spotted Owl. Portland,

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17
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1 J.P. (Hamish) Kimmins is Professor of Forest Ecology, Department of Forest Sciences, Faculty of Forestry, University of British Columbia, 

Vancouver, BC.

Managing for Wildlife Habitat in Westside Production Forests

FOREST ECOSYSTEM MANAGEMENT:

MIRACLE OR MIRAGE?

J.P. (Hamish) Kimmins1

ABSTRACT

Forestry is, first and foremost, about people. We are faced with a three to four billion increase in the human population

within this century, and steps should be taken to ensure that the multiple resource values and environmental services provided by existing forests are sustained and, wherever possible, depleted forests renewed. Forestry must balance the diverse

short-term needs and desires of today’s human population, the anticipated needs of future generations, and the maintenance

of long-term forest ecosystem conditions, functions and organisms. The most effective way to satisfy these obligations may

be to use the paradigm of ecosystem management (EM) as the template for forestry. Ecosystem management requires longterm tenure and the management of all desired values and services under an integrated management plan that spans at least

one full rotation (multiple rotations for short rotation timber crops) and has inputs from multiple stakeholders. The management plan should cover a defined forest area sufficiently large to permit the management of key ecological processes. All

marketable values should be managed under a single plan to facilitate value tradeoff analysis, and targets for the management of non-marketable values should be an integral part of the plan rather than merely a constraint on the profits from 

a single marketable value such as timber, as is often the case. These ideas are not new, but have proven to be difficult to

implement. Fundamental to achieving EM is appropriate tenure systems of adequate duration and area, the involvement of

multiple stakeholders in setting management objectives, active management and marketing of multiple values at the landscape scale, and the explicit definition of a “desired forest future.” The tenure system should permit the management of the

entire forest landscape ecosystem as a single endeavor, with economic rewards to the managing agency, consortium or collective for all marketable values, while targets are set for the maintenance, at the landscape scale, of non-marketable values.

Equally fundamental is the need to understand and respect the ecology of the resources and other values that are to be 

sustained, including the critical role of ecosystem disturbance in sustainability.

One of several major impediments to implementation of EM has been the lack of, or failure to use, ecosystem management scenario and value tradeoff analysis tools. Multi-value, ecosystem-level decision support systems are required to

evaluate the most effective stand and landscape management strategies to achieve a desired forest future. Such tools should

incorporate both the ecosystem processes responsible for biophysical sustainability, and the social values that relate to social

and economic sustainability. In the absence of these and other prerequisites for successful EM, this logical endpoint in the

evolution of forestry may remain an “ecotopian” ideal rather than a practical reality: a mirage rather than a miracle. While

the evolution from administrative forestry to ecosystem-based forestry constitutes major progress, it is not enough and we

should continue to press to make EM a reality.

KEYWORDS: Ecosystem management, pre-requisites for ecosystem management, ecosystem-level decision support tools,

visualization, ecological rotations, ecological “theatre.”

19
INTRODUCTION

The good news is that human population growth is

slowing. The bad news is that the world’s forests will have

to service the needs and desires of another three to four 

billion people by the end of this century (Lutz et al. 2001).

The current population of about 6.7 billion is posing unpre- cedented pressure on the world’s forests, especially in

developing countries at tropical and subtropical latitudes. 

A plethora of new paradigms have been suggested as a

template for managing the world’s forests in the face of

this human pressure. These include ecosystem management

(EM), adaptive management (AM), zonation, emulation of

natural forest disturbance (ENFD) and natural/historical

range of variation (NRV/HRV), concepts that are not mutually exclusive and will often be employed in combination

(Kimmins 2004a). 

In this paper I review my interpretation of forest EM

and what I perceive to be some of the major impediments

to achieving it. I then discuss the planning and communication tools needed for the design and assessment of EM that

will be necessary for public acceptance of this forest management paradigm. The paper closes with an assessment of

the likelihood that EM will come to dominate forestry.

FOREST ECOSYSTEM MANAGEMENT:

BUZZWORD OR MEANINGFUL

CONCEPT?

Forestry is constantly facing new social pressures,

ideas, buzzwords and paradigms. Politically correct and

trendy assertions are constantly being made about forestry

and how it should change. These are often made by wellintentioned but frequently incompletely informed public

pressure groups. Foresters, forest companies and government forest-related agencies have often responded to these

social pressures in an equally uninformed manner. There is

an urgent need for clearer definitions of suggested new paradigms, including EM, and for the ability to forecast their

social and environmental consequences over both short and

long time scales and small and large spatial scales before

they are implemented. Only when we are equipped with

these forecasts can we have some confidence that the suggested new approaches to forest management will indeed

honor intergenerational equity issues, and not just indulge

short term desires and preferences. 

Forestry is the art (skill), practice, science and business of managing forest stands and forested landscapes to

sustain the balance of values and environmental services

that are ecologically possible and desired by society. There

are two corollaries of this definition. 1) Forestry should

change when society changes the desired balance of values

if existing polices and practices are not appropriate for the

new balance. 2) Suggested changes should be resisted if

these are inconsistent with the ecology and sociology of the

desired new set of values. As society comes to an understanding of the integrated and dynamic, ever changing

character of forest ecosystems, it is increasingly demanding

“ecosystem management” as a replacement for traditional

timber or other single value management. It is the responsibility of the forestry profession to make this transition

once it is clear what is meant by EM, but only after an

assessment that the management practices envisaged by

some particular definition of EM will respect the ecology

of the forests and values in question. The vision of EM

must have a high probability of satisfying the needs of both

local people and society in general, both now and in the

future; it must also recognize that desired values at different time and space scales can sometimes be in conflict.

Once these issues have been assessed and a strategy to

address them devised, foresters will face the difficult challenge of persuading the public to accept what needs to be

done to achieve EM.

The term ecosystem management has seen increasing

usage over the past two decades. Vogt et al. (1997) present

a history of development of ecosystem ideas in forestry,

largely in North America, including the development of 

the use of the term EM. Background on the development 

of the EM concept can be found in Agee and Johnson

(1988), Gordon (1993), Grumbine (1994), Christensen et

al. (1996), Boyce and Haney (1997), Kohm and Franklin

(1997), Schlaepfer (1997), Vogt et al (1997), D’Eon et al

(2000), Kimmins (2004b) and Perera et al (2004). Much of

the discussion of EM has focused on biophysical aspects

(e.g. Lindenmayer and Franklin et al. 2002, Burton 2005),

but the social aspects must also be given adequate (= equal,

once the biophysical possibilities have been established)

consideration (Slocombe 1993). This is essential since

forestry is about people – their needs, desires and values.

Focus on any one subset of EM will cause this desirable

management paradigm to fail.

From the outset, EM has been poorly defined, ambiguous and subject to diverse interpretations. The recent 

origins of the term lie in the evolution of new paradigms

and nomenclature in forestry that occurred in the Pacific

Northwestern U.S. in the 1980s. These developed in

response to concerns about wilderness, antipathy towards

clearcutting and the harvesting of old growth forests, and

the issue of the northern spotted owl. The central question

was whether it was better to have relatively few but large

20
reserves of old forest within a matrix of young, even-age

forests managed by conventional silviculture, or to maintain elements of old forest scattered throughout the younger

forest landscape in the new form of silviculture envisaged

by “New Forestry.” This term aroused considerable opposition, largely based on a lack of comprehension of the

objectives of this new approach (Kimmins 1997a) and

because it was ubiquitously and prescriptively applied, so it

was replaced by “Forest Ecosystem Management,” a term

that could be more understandable and acceptable to the

critics of forestry and the public at large. The most recent

evolution of concepts associated with the EM approach to

forest stand management is associated with variable retention silviculture and structure management silviculture that

includes variable density thinning (Carey and Johnson

1995; Carey and Curtis 1996; Franklin et al. 1997, 2002;

Mitchell and Beese 2002; Lindenmayer and Franklin et al.

2002). 

There are many different interpretations of EM. The

one presented here is somewhat broader than that envisaged by some, perhaps because it is inclusive of much of

the diversity of interpretations of EM. Understanding EM

must start, with an understanding of forest ecosystems.

What is a Forest Ecosystem?

Forest ecosystems are areas of the landscape that are

dominated by trees and consist of biologically integrated

communities of plants, animals and microbes, together with 

the local soils (substrates) and atmospheres (climates) with

which they interact. Forests are much more than the present population or community of trees. Forests that have

been recently killed or altered by fire, insects, disease,

wind or logging are still forests because of the biological

and physical legacies from the previous forest – legacies of

forest soil, organic matter, microbes, minor vegetation and

animals. Under a regime of sustainable forest management,

many or most of these legacies persist during the period

between forest disturbance and the redevelopment of tree

cover. As long as the processes of ecosystem development

are active within the historic range of variation, the temporary structural change in the ecosystem is not synonymous

with ecosystem destruction or damage as is often asserted.

Forest ecosystems are both a stand-level and a landscape phenomenon, the latter being a mosaic of stands that

vary in age, species composition, structure, function and

time since disturbance. Forest landscapes generally include

areas such as lakes, rivers, rock outcrops, and shrub, herb

and other non-treed communities. However, the character

of these non-forest inclusions is strongly influenced by

their location in the forested landscape. Periodic disturbance is a key attribute of most forest ecosystems, and

maintenance of their historical character and values will

generally require maintenance of historical disturbance

regimes, or the ecological effects thereof (Attiwill 1994,

Perera et al. 2004). 

Because a forest ecosystem is an integrated biophysical system, a forest is as much a set of ecosystem processes

as a set of forest ecosystem components. Short term changes

in the structure of the forest do not constitute loss of the

forest as long as the processes of the forest ecosystem

remain in operation at acceptable levels.

What is Forest Ecosystem Management?

Management is the act of controlling, directing,

administering or regulating an object or system. Forest

management is the management of forests to achieve a set

of management objectives. Forest ecosystem management

(EM) approaches forest conservation, utilization, administration and regulation on the basis that the forest is a highly-integrated, complex, generally resilient, multi-value

biophysical system that has thresholds of tolerance for disturbance (either too much or too little) beyond which its

resilience and certain values and environmental services

are changed. Ecosystem management is the management 

of forest ecosystem processes and disturbance regimes to

sustain the desired values and ecosystem services from a

shifting mosaic of different ecosystem conditions across

the landscape, and a non-declining pattern of change over

time in the values and services provided by each stand in

that landscape. It is also the management of the human use

of, and interactions with, the forest because humans are

part of forest ecosystems.

Based on these definitions, it is clear that forest

ecosystem management is far more than a politically correct buzzword, although it has frequently been used as

such. However, if we are to be successful in implementing

it as the biophysical template for sustainable, multi-value

forestry, we must understand the impediments to, and necessary conditions for, its successful application. Successful

application of the EM concept as the basis for forestry

involves much more than the simple acceptance that EM 

is a nice idea. 

ELEMENTS OF FOREST ECOSYSTEM

MANAGEMENT

There are many suggested lists of the basic attributes

of EM. According to Christensen et al. (1996) it includes

the following elements: 

21
• Sustainability—EM does not focus primarily on 

“deliverables” but rather regards intergenerational 

sustainability as a precondition. 

• Goals—EM establishes measurable goals that specify

future processes and outcomes necessary for sustainability. 

• Sound ecological models and understanding—EM 

relies on a scientific approach to understanding at all 

levels of ecological organization (note the need for all

three components of science – knowing (experience,

inductive), understanding (experimental, deductive) 

and predicting (synthesis, projection Kimmins et al.

2005). 

• Complexity and connectedness—EM recognizes that

biological diversity provides the genetic resources 

necessary to adapt to long-term change, and structural

complexity may strengthen ecosystems against disturbance. 

• The dynamic character of ecosystems—Recognizing 

that change and evolution are components of ecosystem sustainability, EM avoids attempts to “freeze”

ecosystems in a particular state or configuration. 

• Context and scale—Ecosystem processes operate over 

a wide range of spatial and temporal scales, and their

behavior at any given location is greatly affected by 

surrounding systems. Thus, there is no single appropriate scale or timeframe for EM. 

• Humans as ecosystem components—EM values the

active role of humans in achieving sustainable management goals. 

• Adaptability and accountability—EM acknowledges 

that current knowledge and paradigms of ecosystem

function are provisional, incomplete, and subject to

change. Management approaches must be viewed as

hypotheses to be tested by research and monitoring 

programs. 

There are also several different lists of the key themes

in ecosystem management. The following is a distillation

of those lists (Kimmins 2004a):

• Establish a clear set of management goals (objectives

– a desired forest future) that respect the ecological 

tolerances and resilience of the ecosystems, species, 

and values of interest. 

• Manage forests as ecosystems, crossing levels of 

biological organization and integration. 

• Define management areas ecologically, and vary the

practices of management to respect the ecological and

biological diversity therein. 

• Assign the management of forest ecosystems at both

the stand and landscape scales, over a defined forest

area and for ecologically appropriate time scales, to a

single agency or organization under a single plan that 

has the mandate to manage for a sustained balance of

values across the landscape and the temporal variation 

in these values in any one stand. Management under a

single integrated plan greatly increases the probability

that value tradeoffs will be managed successfully.

• Maintain ecosystem function, seral sequences, and

species composition within historical ranges of 

variation (emulation of natural forest disturbance

–ENFD) or a socially acceptable yet ecologically 

sustainable subset thereof.

• Manage adaptively, constantly learning and changing

practices as indicated by monitored outcomes, and 

using ecologically-based forecasting tools to support

management planning where experience does not yet

provide the needed guidance over ecologically and 

management-relevant temporal and spatial scales.

• Risk spreading – avoid applying the same practices

everywhere.

It should be clear from these two lists that the task of

defining EM is not a simple one. Ecosystem management

is more of a management philosophy than a specific management method, and the application of EM will vary considerably from one type of forest to another, and according

to the needs of people and other organisms, which also

vary in time and from place to place.

ECOSYSTEM MANAGEMENT IS 

MORE THAN ECOSYSTEM-BASED 

MANAGEMENT

The terms ecosystem management (EM) and ecosystem-based management (EBM) are often used interchangeably. I believe that they are different. 

EBM is the management of individual resources and

values based on respect for their ecology and the ecological

role they play in the forest ecosystem. However, it is not

implicit in EBM that all forest resources and values will be

managed in an integrated, coordinated manner under a single forest ecosystem management plan. EBM therefore

provides less assurance than does EM that the key ecosystem processes that play out over long periods of time and

over large areas will be managed in a way that sustains the

desired balance and diversity of values and ecosystem conditions. It is my opinion that there is less chance that EBM

will satisfy the attributes and themes of EM listed above

than EM implemented under an appropriate ecosystem

management plan.

22
SOME PREREQUISITES FOR FOREST

ECOSYSTEM MANAGEMENT

The following is a list of the many conditions that

must be met before EM can become an effective paradigm

for forestry. 

Appropriate Tenure Systems

Forests can only be managed as ecosystems if all values are managed under a single, integrated, multi-value and

ecologically-based plan implemented by a single agency/

organization/collective over time scales that are consistent

with the ecosystem processes responsible for resilience and

sustainability. The tenure and plan should also cover an

area large enough to encompass the key ecosystem processes. The objectives of the plan must be established by 

a multi-stakeholder process that respects the ecology of 

the local and regional ecosystems and desired values therefrom. 

Most forests are managed today for a single value or

limited value set, with other values being a constraint on

efforts to optimize the target value(s). Most forest companies are licensed to manage only timber values for profit.

While there are often regulations to achieve non-timber

objectives and there may be a requirement for passive management of non-timber resources (e.g. maintain wildlife

habitat), there is rarely explicit financial or other incentives

to encourage achievement of these non-timber goals. They

are simply a constraint on the main management objective. 

This is not EM. Even if the regulations concerning

timber and non-timber management are related to our

understanding of the ecology of these values (ecologicallybased or even ecosystem-based management), only if the

entire forest ecosystem is managed by a single entity under

a single plan can we legitimately refer to EM. This plan

must cover an area sufficiently large to incorporate the key

ecosystem processes responsible for the renewal of desired

values. It must recognize the vital role of ecosystem disturbance and be able to ensure appropriate disturbance

regimes, or emulate the effects thereof (Attiwill 1994;

Kimmins 1996a, b, 2004; Perera et al. 2004). It must be

based on scenario analyses that permit evaluation of tradeoffs between different values both in time and space. For 

a more in-depth discussion of ecosystem management

tenures see Kimmins (2006).

Establishment of Overall Long-Term Objectives

There must be an explicit definition of a “desired forest future.” This must replace a simple statement of objectives with respect to individual values. A static, snapshot

view of these values must be replaced by a dynamic assessment. What is the desired pattern of change over time in 

the characteristics of individual stands and the overall landscape? How will the availability and location of different

values vary over time? Only when the management plan

has a statement of the full range of values and conditions

that are to be available at various times and locations in the

future can there be a plan as to how to achieve this. Shortterm values are important, but these must be balanced

against the achievement of long-term goals. 

Adequate Inventory 

An ecosystem management plan must be based on an

inventory of ecological, biological and social characteristics. There must be ecological site classification - the zonation of the forest landscape being managed into reasonably

homogeneous climatic zones, topographies and soil types

(different “ecological stages” to use the metaphor of “ecological theatre” (Kimmins 2004)) that define the biological

potential of the land (fig. 1). There must be an inventory 

of the different biotic communities (the “ecological plays”

and “ecological actors” in figure 1) – different forest types,

ages, conditions and values – associated with this ecological diversity. And there must be an inventory of the variety

of social values being managed, their spatial distribution

across the landscape and how they change as a shifting

mosaic over time.

Acceptance of the Dynamic Nature of Ecosystems 

A key prerequisite for ecosystem management is

acceptance of the dynamic nature of forest ecosystems, 

and the role of ecosystem disturbance in the long-term

main-tenance of desired values. Disturbance may lead to

short-term reductions in some values, but may be required

to sustain the same values over the long-term. Where such

disturbance is necessary for desired future levels of measures of biodiversity, beauty, productivity, employment and

other values, there must be an acceptance of short-term

change. The forest is not some ancient cathedral. It is 

not an art gallery of unchanging images. It is a dynamic,

changing ecological system, the integrity of which requires

change at some level, spatial scale and frequency.

Sustainability of forest ecosystems is not related to

lack of change. At the stand level it is non-declining patterns of change over time, either within the natural (or historical) range of ecosystem variation or within a socially

acceptable subset thereof. At the landscape scale, it is a

shifting mosaic of changing stand level conditions, the

overall character of the mosaic remaining reasonably 

constant over time.

23
Communication of this dynamic nature of sustainability requires ecologically-based planning tools linked 

to visualization and other output systems. 

Founding the Management of Forest Ecosystems 

on the Concept of “Ecological Rotations”

Because of the vital ecological role of ecosystem disturbance, and because forest management involves management of “natural” and human-caused disturbance,

sustainable EM should be founded on the concept of “ecological rotations” (Kimmins 1974). 

An ecological rotation is that combination of severity,

scale, pattern and frequency of ecosystem disturbance and

ecosystem resilience (speed of return to predisturbance

condition, or to some desired new condition) that results in

non-declining patterns of stand level change, and a shifting

landscape mosaic of acceptably constant overall character

(fig. 2).

The ecological rotation concept provides foresters with

choices. If rotations are to be short for economic or other

reasons and this creates a greater-than-historical frequency

of disturbance, this may need to be matched by a lowerthan-historical severity and scale of disturbance, depending

on the natural disturbance regime to which the ecosystem

in question is adapted. Similarly, where a higher-thanhistorical severity of disturbance is required for ecological

or social reasons, the frequency of disturbance should be

reduced (longer rotations). Alternatively, management

interventions can be made to increase the resilience of the

ecosystem (e.g. planting, competition control, fertilization)

so that more frequent and/or more severe disturbance

remains sustainable.

Different values have different ecological rotations,

which suggests that variable retention silviculture (different

elements within the ecosystem are managed on different

ecological rotations) should be a major component of ecological rotation-based forestry.

24

Figure 1—Diagrammatic representation of the concept of “ecological theater.” Only one or a few plant species (“actors”) are shown for each “act” (seral

stage and its biotic community) of the ecological “play” (the successional sequence of communities/seral stages), whereas in reality there will be many

species (“actors”) “on stage” in each “act”. This diagram implies that the “script” or “storyline” for the “ecological play” is constant and will be repeated

exactly following ecosystem disturbance. In reality, it can vary according to different types, severities, spatial scales and timing of disturbances, differences in ecosystem character and condition, and the resultant variation in the processes of ecosystem development. “Biodiversity” refers to the diversity 

of genes, species and biotic communities. The physical diversity of the landscape and physical disturbances constitute “ecological diversity.” This is the

environmental framework within which biodiversity develops; it is not in itself biodiversity, contrary to the many definitions that claim that it is. Temporal

diversity is the change in biotic and local physical conditions over time. Note that “old growth” – a phase of stand dynamics – develops at the end of each

“act” (seral stage) of the “ecological play” (after Kimmins 2005).
25

Figure 2—Concept of ecological rotations. Post-disturbance restoration of ecosystem conditions and values depends

on severity and frequency of disturbance and rate of ecosystem recovery. Non-sustainability can result from a frequency that is too high for a particular severity and recovery rate (A); a rate of recovery that is too slow for a particular frequency and severity of disturbance (B); and a severity of disturbance that is too great for a particular 

frequency and rate of recovery (C). A, B and C depict a sustained repetition of the levels of the three variables –

something that is generally unlikely to occur. D shows a more realistic scenario in which the severity and frequency

of disturbance will vary over time. It shows that a wide range of disturbance severity and frequency can be sustainable if the other of these two variables is changed appropriately. Management alteration of the rate of ecosystem

recovery adds a third dimension of complexity and choice.
Selection of that balance of frequency, severity, scale

and management of resilience that meets the objectives of

EM most effectively is a challenging task. It calls for ecologically based planning tools – ecosystem management

models – capable of dealing with ecosystem processes,

multiple values, the spatial and temporal scales involved,

and the interactive effects of severity, scale, frequency of

disturbance and ecosystem resilience. Conventional tree

population models that have provided the basis for decision-support tools in timber-focused forestry in the past are

simply inadequate for this task.

The ecological aspects of disturbance are explored in

detail in Kimmins (2004b) and Perera et al. (2004).

Economic Sustainability

Unless forestry is economically viable it may revert to

exploitation, which is not forestry. Forest ecosystem management is based on the concept that humans are part of

and dependent on forest ecosystems, and therefore in self

interest, if for no other reason, we should manage them

sustainably. The management tasks required to do this are

expensive. Exploitation is cheaper in the short-term. To

prevent forest ecosystem management from becoming

exploitation under the guise of managing ecosystems, the

endeavor must be economically viable. Where the economics of forestry is marginal, over-cutting may occur. By marketing non-timber as well as timber products – a major

feature of EM – forestry that is uneconomic based on timber alone may become economic. Where the economics 

of stand thinning prevents this silvicultural practice, sustainable harvesting and marketing of understory plants for

floriculture may render thinning economic where there is

an adjacent market for such products and for those ecosystems that support sustainable communities of floriculture species. This would probably only work if a single

agency were able to market and collect revenues from a

variety of forest products – timber and non-timber – and

marketable services. Thinning reduces the accumulation of

dead trees in the ecosystem by reducing inter-tree competition and related mortality, which will reduce those values

that are dependent on dead wood. EM requires that the

implications of different silvicultural scenarios be assessed

both economically and for non-timber values.

Planning and Communication Tools 

The establishment of EM objectives involves recognition of the biological possibilities and limitations in the

area being managed. It requires the ability to forecast the

biological, environmental and social consequences of 

different strategies to achieve the desired forest future.

Establishment of ecologically and socially achievable 

objec-tives and evaluation of the most acceptable way of

satisfying these requires planning tools that have capabilities far in excess of those traditionally used in forestry. It

also requires an improved capability to communicate the

output of such tools to the public. 

Traditional planning tools have generally been limited

to stand-level growth and yield models, and landscape/ 

forest estate timber supply models driven by these stand

models. Multi-value, estate management models have been

developed, but are generally based on simple assumptions

and models that do not address the fundamental ecosystem

processes responsible for sustainability. Because of the

importance of involving multiple stakeholders in the development of management plans, planning tools should have

outputs that facilitate understanding by non-technical people of the choices available and the accompanying value

tradeoffs. The analytical output (graphs, tables, maps) that

foresters deal with are poor communication tools for many

in the general public. To complement this quantitative, 

analytical output, planning tools should be linked to visualization systems: scientifically-based (representing key

ecosystem processes) simulated images of the future states

of stands, landscapes and their values integrated into

movies that span the time and space dimensions of the

issues in question (Sheppard and Harshaw 2000, Kimmins

1999, 2000). 

All the new paradigms for forestry listed earlier

require the use of such planning and communication tools,

not just EM. 

ECOSYSTEM MANAGEMENT MODELS

AS COMMUNICATION AND PLANNING

DECISION SUPPORT SYSTEMS

Setting objectives, assessing tradeoffs between values, 

balancing the needs of the present generation against the

legacies we want to pass to future generations, and communicating choices, risks, uncertainties and possible outcomes to the public requires the use of a new generation of

decision support tools. Traditional planning tools will continue to be essential. These range from forest site classifications, to GIS systems, to timber supply analysis tools.

However, the increasing complexity of forestry and the

imperative to manage forest ecosystems rather than populations of trees or individual games species require decision

support tools that can address this complexity. This can be

provided by forest ecosystem management models (Messier

et al. 2003). These should be linked to user-friendly interfaces and visualization systems (Sheppard and Harshaw

2000) to facilitate their use by the non-technical public. 

26
Forest decision support tools fall into three major 

categories: experience-based, empirical (historical bioassay

(HB) models; e.g. growth and yield models); knowledgebased (process simulation (PS) models); and hybrid simulation (HS) models that combine both experience and

knowledge in hybrid historical bioassay-process simulation

systems (Kimmins 1990). The emerging consensus is that

HB models will always be useful in forestry for short term,

tactical, individual value decisions; that PS models are

needed especially in research and to assist in understanding

ecosystems (Korzukhin et al 1996; Johnsen et al. 2001) 

but that they are often too complex to use in forest management (Mohren et al. 1994); and that a hybrid of the two

– HS models – will be the way of the future (Zeide 2003,

Landsberg 2003). 

There is growing acceptance of the need for forestry

models to address the complexity of forest ecosystems and

their management. This reflects the adage: a problem is 

an issue that does not get solved; an issue that gets solved

quickly is not a problem; problem issues often persist

because they are complex and people offer only simple

solutions. This trend also honors the full intent of the principle of parsimony – Occam’s Razor – that theories, explanations and models should be as simple as possible, but as

complex as necessary. As Einstein noted, make everything

as simple as possible, but not simpler.

Messier et al. (2003) review a variety of stand and

landscape models for use in sustainable forest management

planning, and the literature and the internet are rich in

information about the rapidly expanding choice of models

as research, decision support and communication tools in

forestry. I mention here a selection of the models I am most

familiar with as an example of the type of EM model that I

believe is needed now, and will be needed increasingly in

the future.

Twenty-nine years of development of forest ecosystem

management models by the Forest Ecosystem Management

Simulation Group at University of British Columbia’s

Department of Forest Sciences has produced a range of

hybrid simulation ecosystem management decision support

tools. The computer model, FORECAST (FORest and

Environmental Change ASsessmenT), is a non-spatial,

multi-value, stand-level, ecosystem management simulator

that represents key ecosystem components and processes

and can simulate all major stand management activities

(Kimmins et al. 1999; Seely et al. 1999, 2002). The

FORECAST model has been used to replace traditional

tree growth and yield models in timber supply models such

as ATLAS (Forest Planning Studio), converting it to a 

landscape ecosystem management model. The FORECAST

model is also used to simulate the stands in a small-tomedium-scale watershed landscape model, Possible Forest

Futures (PFF), which is designed as a multi-value, scenario

analysis and value trade-off tool for education, extension

and public participation processes, as well as forest management gaming. A spatially-explicit, individual-tree, complex stand model, FORCEE, is under development based

on FORECAST, which is also being used in LLEMS

(Local Landscape Ecosystem Management Simulator), an

adaptation of PFF for the design and assessment of complex cutblocks of up to 2,000 ha. The LLEMS model is

intended for the evaluation of alternative variable retention

harvesting and structure management silviculture – ecosystem management - designs. All these tools have userfriendly interfaces so that, once calibrated, they are

accessible to relatively non-technical users, and they are

linked to visualization output tools including the preparation of movies of possible futures for multiple values under

different management scenarios. They provide a basis for

comparing visual assessments with evaluations of ecosystem responses (Kimmins 1999, 2000a), the degree to which

different management paradigms and methods respect

nature (Kimmins 2000b), and how we can evolve forestry

to deal with the case of “future shock” that it is currently

undergoing (Kimmins 2002). 

Visualization tools always pose the distinct risk of

being merely “pretty pictures” (“Potemkin Villages”;

Sheppard and Harshaw 2000; Sheppard 2001), of overimpressing the viewer by technical elegance, and of failing

to convey the great uncertainty and risks inherent in predicting the future. Nevertheless, the reality is that the public are generally better able to understand and evaluate

forestry through pictorial than through tabular, graphical

and 2-dimensional map representations. The key is to

ensure that the scientific basis for the images being presented is also communicated in as understandable a format

as possible in order to establish a level of confidence in the

images. Users of visualization tools should also ensure that

the message is never given that there is only one possible

future. The visualizations should incorporate representations of natural and human-caused risks and uncertainties,

and clearly communicate that there are many different possible forest futures – there is a variety of “ecological plays”

that are possible on a particular “ecological stage.”

An important question with respect to forestry models

is: can they be used by foresters in developing countries, or

are they tools restricted to foresters in wealthy, developed

countries? While it is true that there are knowledge and

technology barriers that limit the use of such tools in many

27
parts of the world at present, computers are rapidly becoming omnipresent wherever there is electricity. Computer

models can harness knowledge and experience from developed countries at any latitude, and make them available as

heuristic, educational and extension tools to countries that

presently lack the wherewithal to locally calibrate and use

such tools. Local traditional knowledge can also act as an

“expert system” by which to undertake initial calibration. 

It may be some years or decades before foresters in less

developed countries gain the local information needed to

make them accurate tools for local prediction, but the day

when this will be possible is approaching, and it is time 

to start to customize this type of tool for this future use.

Several forest ecosystem models already exist for tropical

forests, and there are many for temperate forests. Their

development should be continued in anticipation of the 

day that foresters in developing tropical and temperate

countries are ready for them. Equipping these models for

agroforestry assessment as well as forest management

applications is also important

CONCLUSIONS

The prime directive in forestry is to change as the 

balance of desired forest values and environmental services

changes, but an equally important responsibility is to resist

change that is inconsistent with the ecology and the sociology of the desired new balance of values. To respond in a

responsible and ethical manner to the challenges posed by

the addition of three to four billion to the global human

population, foresters must stop managing forests for timber, or for wildlife, or for water, or for any other single

value individually. They should be managed as ecosystems

for multiple values. This does not imply that all forests are

managed for all values all the time. Wilderness, ecological,

genetic and potable water production reserves and recreational areas will be part of the mosaic of different land

management designations within a forest landscape, but the

whole should be managed as a landscape ecosystem. Park

and others reserve boundaries do not stop fires, insects, 

diseases or timber/wildlife poaching. Forestry that fails to

address the human needs of local people, or to respect the

processes of local and landscape ecosystems, is unlikely to

be sustained or sustainable. Only when the forest is managed as a system with people and their multiple values

respected and incorporated into management will we

reduce conflict in forestry and balance the multiple and

competing demands of today’s generation against our

desire to leave a suitable legacy for the future. 

Forestry is primarily about people, not ecology, biodiversity, timber or any other single value. The fact that

ecology is now the essential biophysical foundation for

forestry, and that wildlife, water and biodiversity have

become as important in forestry as timber, is because people have recognized their value and have insisted that they

become an objective of management. If foresters are to

obtain the social license to manage the world’s forests, 

they should strive to implement ecosystem management,

with humans as part of the ecosystems. Many changes are

required to achieve success in this vital endeavor. One 

of them is the synthesis of ecological knowledge, both 

“traditional” and that derived from “western science,” into

ecosystem management scenario analysis and visualization

tools.

A final and critically important element of implementing EM is public trust. This is perhaps the greatest challenge to foresters, but it will not be gained over the long

run by acquiescence to “flavor-of-the-month” beliefs and

unfounded assertions about forest ecosystems. Stewardship

and forest ethics ultimately must be based on an integration

of experience (including “traditional knowledge”), human

values and science-based understanding of forest ecosystems.

Forestry has always been changing, and will continue

to do so. This is implicit in the “prime directive” identified

in the definition of our profession. The evolution will hopefully take us to ecosystem management, and not “leave us

at the station” of ecosystem-based management, useful

though this is. At the present time the impediments to the

widespread application of EM render this an ideal to aim

for rather than a fully operational system of management.

Overcoming these impediments involves recognizing them

and taking energetic steps to overcome them. Space limitations prevent further exploration of these ideas here, but

the reader might seek the paper on EM tenure reform noted

above (Kimmins 2006).

LITERATURE CITED

Agee, J.; Johnson, D., eds. 1988. Ecosystem management 

for parks and wilderness. Seattle, WA: University of

Washington Press. 237 p.

Attiwill, P.M. 1994. The disturbance of forest ecosystems: 

the ecological basis for conservation management.

Forest Ecology and Management. 63: 247-300.

Boyce, M.S.; Haney, A. 1997. Ecosystem management. 

applications for sustainable forest and wildlife

resources. New Haven, CT: Yale University Press. 

361 p.

28
Burton, P.J. 2005. Ecosystem management and conservation biology. In: Watts, S.B.; Tolland, L. Forestry

Handbook for British Columbia. 5th ed. Vancouver,

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SILVICULTURAL

APPLICATIONS
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1 Joan Hagar is a Wildlife Biologist, USGS- Forest & Rangeland Ecosystem Science Center, 777 NW 9th St, Suite 400, Corvallis, OR 97330.

Managing for Wildlife Habitat in Westside Production Forests

KEY ELEMENTS OF STAND STRUCTURE 

FOR WILDLIFE IN PRODUCTION FORESTS WEST

OF THE CASCADE MOUNTAINS

Joan C. Hagar1

INTRODUCTION

Silvicultural treatments can significantly influence abundance and distribution of wildlife through manipulation of

vegetation at the stand level (McComb 2001). Manipulations

to stand structure and composition are likely to directly

affect wildlife species whose home ranges are smaller than

or equal to a typical unit managed as a stand, and thus have

the potential to influence wildlife community composition.

Structural diversity is a key characteristic of stands, representing resources available for wildlife (Hunter 1990). The

number of species that find suitable habitat in a stand increases with increasing structural diversity for two reasons.

First, each species relies on a diversity of resources to meet

its needs; i.e., most species use different resources for cover

than for foraging. Therefore, the combination of resources

for foraging and cover is necessary to provide suitable

habitat for individual species. Second, each species has

unique habitat requirements, so a diversity of resources is

ABSTRACT

Silvicultural practices have an important influence on wildlife habitat by manipulating stand structure. Forests managed

for timber production tend to have simplified structure compared to natural forests due to the emphasis on mid-seral stage

conifers. Large diameter trees, snags, and logs, and floristic diversity are necessary to maintain habitat for forest wildlife,

yet typically are underrepresented in intensively managed forests. Trees that develop complex structure over time offer an

array of unique niches that contribute to wildlife diversity at the stand scale, and legacy trees provide refugia and dispersal

habitat for species associated with older forests. Snags and down wood are critical habitat elements used by more than 150

species of wildlife in Northwest conifer forests. Current guidelines for augmenting volumes of woody debris in managed

forests may be inadequate to maintain populations of all associated species in intensively managed forests. Floristic diversity, in particular the presence of shrubs and hardwood trees, provides important food and cover resources for a surprising

number of species in coniferous forests. Allowing greater development of non-coniferous vegetation in managed forests

would make a significant contribution to the maintenance of wildlife diversity. Production forests can enhance wildlife habitat throughout all phases of stand management by incorporating the key elements of stand structure discussed in this paper.

KEYWORDS: Coarse wood, floristic diversity, stand structure, wildlife habitat.

35

necessary to support a diversity of species. Structurally

complex stands support an array of niches that can be

exploited by a diversity of species. 

Structural diversity is missing from many forests that

emphasize timber production because an emphasis on conifers in mid-seral stages typically leads to homogeneous,

simplified stand structure (Hansen et al. 1991). Key structural features for wildlife that are missing or are relatively

underrepresented in production forests include large trees,

snags and logs, and a diversity of tree and shrub species

(Carey and Johnson 1995, Bunnell et al. 1999). Forest

regeneration systems that remove all components of the

previous stand have substantially reduced the number of

trees, snags, and logs that represent the upper range of

diameter distributions characteristic of natural forests. A

focus on early establishment of conifers on forestlands

managed for timber production also has truncated the

diverse, shrub-dominated stage of forest succession. Rapid
establishment of conifers following clear-cutting, involving

vegetation management and narrow spacing of conifer

seedlings to reduce competition from other species (Walstad

and Kuch 1987), has produced young, closed-canopy second-growth forests across thousands of hectares in the

Pacific Northwest. This stand condition is productive from

a timber management perspective, but the homogeneous

structure supports low diversity of wildlife (Hayes et al.

1997).

Although many wildlife species often are associated

with particular seral stages of conifer forests (Bruce et al.

1985), most species are actually more responsive to the

availability of structural features that tend to be correlated

with stand age in managed forests than to stand age per se

(Bunnell et al. 1997). For example, species that reach their

highest abundance in old-growth Douglas-fir (Pseudotsuga

menziesii), such as the spotted owl (Strix occidentalis) and

many species of cavity-nesting birds, also occur in younger

natural forests that support the necessary habitat elements,

large trees and snags (Carey et al. 1991, Huff and Raley

1991, Lundquist and Mariani 1991). Similarly, many wildlife species that are commonly associated with early seral

habitat can occur with great regularity and in abundance

throughout all stages of forest development when suitable

understory cover is present. In a chronosequence of unmanaged forest stands throughout Oregon and Washington,

understory characteristics had low discriminatory power

among age classes (Spies and Franklin 1991), and most

vertebrate wildlife species associated with understory vegetation did not differ in abundance among forest age classes

(Ruggiero et al. 1991). This suggests that the maintenance

of key structural features throughout forest development

could help maintain habitat for a diversity of native wildlife, even in intensively managed forests. The goal of this

paper is to describe the importance of large trees, snags,

and logs, and floristic diversity in supporting key wildlife

species, and to review management options for retaining

these features in forests managed for timber production. 

KEY STRUCTURAL FEATURES

Large Trees

As trees age and increase in size, they develop increasingly complex structural characteristics that provide a

diversity of niches for wildlife. Habitat attributes such as

large limbs, decay and disease infestation sites, and complex bark structure are positively associated with tree size

(Bull et al. 1997). Large-diameter limbs provide resting

and nesting platforms for many species of arboreal mammals and birds, including marbled murrelets, Brachyramphus marmoratus (Hamer and Nelson 1995). Thick

horizontal branches also support abundant growth of epiphytes, which in turn provide nesting material, forage, and

a source of arthropod prey for insectivores (Pettersson et

al. 1995). Lichens that grow close to the ground on large

limbs of open-grown trees, or on limbs fallen from higher

in the canopy provide important forage for herbivores such

as deer (Odocoileus spp.) and elk, Cervus canadensis

(Richardson and Young 1977, Maser et al. 1984). Abundance

of epiphytic lichens is positively associated with branch

size and age because large branches offer more growing

substrate and because lichen colonization and growth is a

relatively slow process (Esseen et al. 1996). Large branches, deformities, witches’ brooms, and other structural irregularities of older trees provide nesting and resting cover for

species such as northern flying squirrel, Glaucomys sabrinus (Maser et al. 1984, Carey 1995), fisher Martes pennanti (USFWS 2004), northern spotted owl (Forsman 2003),

and northern goshawk, Accipiter gentilis (Marshall 2003). 

Older live trees are more likely than young trees to develop forms of decay that can function like snags (Bunnell

et al. 2002), such as hollows, natural cavities, peeling bark,

and dead tops or branches. Hollows and large cavities

formed by heartwood fungi in live trees provide critical

roosting habitat for bats (Ormsbee and McComb 1998),

roosting and nesting sites for Vaux’s swifts, (Chaetura vauxi;

Bull and Collins 1993), night roosts for pileated woodpeckers (Dryocopus pileatus; Bull et al. 1992), and den sites for

black bears (Ursus americanus; Bull et al. 2000). Large

diameter (> 50 cm) also is a critical feature of trees, snags,

and logs with hollows used as den sites by marten, Martes

americana and fisher (Raphael and Jones 1997, USFWS

2004). Natural cavities formed when limbs break off from

the bole, or when branches break off from large limbs, are

used for nesting and roosting by secondary cavity nesters

that are unable to excavate their own cavities, such as

nuthatches (Sitta spp.) and chickadees (Poecile spp.).

Changes in bark characteristics as trees grow and age

further increase the complexity of habitat and resources

offered by mature trees. Chickadees, nuthatches, brown

creeper (Certhia Americana), and woodpeckers all glean

spiders, grubs, and other arthropods from crevices in bark

on the boles and branches of trees. The deeper the crevices,

the more invertebrate prey they are likely to contain

(Mariani and Manuwal 1990). This may explain why older

conifers with deeply fissured bark are preferred foraging

habitat for species such as the brown creeper (Weikel and

Hayes 1999). Bark pulling away from bole provides nest

sites for brown creepers and Pacific-slope flycatchers,

Empidonax difficilis (Canterbury 2003, Weikel 2003) and

roosting sites for bats (Barclay et al. 1988). 

36
Large trees that survive stand-replacing disturbances

can provide critical habitat for species associated with

older forests, allowing persistence or facilitating dispersal

following disturbance events. These legacy trees function

as refugia for small organisms with limited dispersal ability, such as amphibians, arthropods (Wessell 2005), and

lichens (Neitlich and McCune 1997). The protection of

gaps, “wolf trees”, and remnant old-growth trees has been

recommended as a strategy for maintaining diversity and

distribution of epiphytic macrolichens (Nietlich and

McCune 1997), many species of which are important 

forage for wildlife, including deer and elk, in Northwest

conifer forests. Retained trees also facilitate dispersal

through otherwise unsuitable habitat for some forestassociated species. For example, relatively even dispersal

of large trees in harvested areas can facilitate movement 

of forest interior species such as the brown creeper

(Rosenberg and Raphael 1986, Brand and George 2001). 

The time required for trees to develop structural characteristics used by many wildlife species associated with

older forests is considerably longer than the typical rotation

age for production forests. In addition, different conditions

than are commonly found in production forests may

enhance some habitat features. Stand density influences

tree architecture because open-grown trees develop deeper

crowns and larger limbs (Tappeiner et al. 2002). The development of limbs large enough to provide nesting platforms

and substrate for epiphytes requires that trees grow in the

open for many decades. Growth rates of trees in contemporary old-growth stands were comparable to plantations with

densities of 40-50 trees per acre (Tappeiner et al. 1997),

suggesting that abundant growing space may be needed for

trees to develop the specific characteristics attributed to

old-growth trees, such as large diameter branches and deep

crowns. Furthermore, the greater taper that develops in the

boles of trees grown at wide spacing increases stability and

longevity of the habitat provided. Stems > 63 cm may

remain standing for 250 years even after they become

snags (Mellen and Ager 2002).

Options for recruiting and maintaining some trees 

with complex architecture include green tree retention at

harvest, the management of some stand components on

longer rotations than those used for timber production, and

density management of young stands. Density management

to achieve wide spacing is recommended where the goal is

to hasten development of large trees, but is not likely to

meet the goals of most production forests. Instead, managers of production forests who want to maintain key habitat components can designate individual trees within stands

for the development of complex architecture associated

with big trees. These wildlife trees should be established 

in gaps or on stand edges to provide the space needed to

develop the desired structure and to protect them from

management operations.

Retaining large live trees also may be an efficient means

of recruiting dead wood habitat because 1) live trees with

partial decay could be considered along with snags towards

meeting dead wood management goals (Rose et al. 2001)

and 2) large trees are the source of recruitment for future

large snags and logs. Because of the longevity of large

diameter trees and the negative relationship between snag

diameter and fall rate, the contribution of a large live tree

to meeting snag retention requirements is likely to last for

multiple rotations.

Dead Wood

Wildlife in Pacific Northwest forests have evolved 

with disturbances that create large amounts of dead wood,

so it is not surprising that many species are closely associated with standing (snags) or down dead wood. Although

numbers of species that use snags and down wood to meet

requirements for food and cover vary by forest type, approximately one-quarter to one-third of forest-dwelling vertebrates are strongly associated with dead wood (Bunnell 

et al. 1999, Hayes and Hagar 2002). In Oregon and Washington, more than 150 species of wildlife are reported to

use dead wood in forests (O’Neil et al. 2001), highlighting

the importance of this critical resource. In general, down

wood provides cover for breeding and dispersal for amphibians, reptiles, and ground-dwelling mammals, while snags

or dying trees provide nesting, roosting, and denning habitat for birds, bats, and small mammals. Thirty-four sensitive and special status species are associated with dead

wood (table 1). These are key species for management 

consideration because their small or declining populations

are often related to loss of suitable dead wood habitat

(Marshall et al. 1996).

Woodpeckers, as primary excavators, also are key species for consideration in dead wood management because

they perform keystone functions in forest ecosystems by

creating cavities for secondary cavity-nesters (Martin and

Eadie 1999) and facilitating the colonization and dispersal

of decay agents (Farris et al. 2004). A diverse guild of 

secondary cavity-users (including swallows, bluebirds, 

several species of ducks and owls, ash-throated flycatcher

(Myiarchus cinerascens), flying squirrel, bats, and many

other species) is unable to excavate dead wood, and therefore relies on cavities created by woodpeckers for nesting

sites. Suitable nest cavities are essential for reproduction,

and their availability limits population size. If populations

37
38

Table 1—Special status species associated with coarse woody debris habitats in Oregon and 

Washington forests

Common name Scientific name OR statusa WA statusb

Cope’s giant salamander Dicamptodon copei S-U none

Larch Mountain salamander Plethodon larselli FCo, S-V FCo, SS

Del Norte salamander Plethodon elongatus S-V none

Siskiyou Mountains salamander Plethodon stormi S-V none

clouded salamander Aneides ferreus S-U none

black salamander Aneides flavipunctatus S-P none

Oregon slender salamander Batrachoseps wrighti S-U none

California slender salamander Batrachoseps attenuatus S-P none

sharptail snake Contia tenuis S-V SC

harlequin duck Histrionicus histrionicus S-U none

bufflehead Bucephala bucephala S-U none

Barrow’s goldeneye Bucephala islandica S-U none

flammulated owl Otus flammeolus S-crit SC

northern pygmy-owl Glaucidium gnoma S-crit none

northern spotted owl Strix occidentalis FT, ST FT, SE

great gray Owl Strix nebulosa S-V none

Vaux’s swift Chaetura vauxi none SC

Williamson’s sapsucker Sphyrapicus thyroideus S-U none

Lewis’ woodpecker Melanerpes lewis S-crit SC

white-headed woodpecker Picoides albolarvatus S-crit SC

three-toed woodpecker Picoides tridactylus S-crit none

black-backed woodpecker Picoides arcticus S-crit SC

pileated woodpecker Dryocopus pileatus S-V SC

purple martin Progne subis S-crit SC

pygmy nuthatch Sitta pygmaea S-crit none

western bluebird Sialia mexicana S-V none

ringtail Bassariscus astutus S-U none

western gray squirrel Sciurus griseus FCo, S FCo, ST

American marten Martes americana S-V none

fisher Martes pennanti pacifica S-crit SE

lynx Lynx canadensis FT FT, ST

long-eared myotis Myotis evotis FCo, S-U FCo, SM

fringed Myotis Myotis thysanodes S-V SM

Townsend’s big-eared bat Plecotus townsendii FCo, S-crit FCo, SC

Pac. western big-eared bat P. townsendii townsendii FCo Fco, SC

Keen’s myotis Myotis keenii S SC

silver-haired bat Lasionycteris noctivagans S-U none

long-legged myotis Myotis volans S-U SM

Yuma myotis Myotis yumanensis FCo, S FCo, none

white-footed vole Phenacomys albipes S-U none

a FCo: Federal Species of Concern; FT: Federal Threatened; S-CR = Sensitive: Critical; S-U = undetermined status; S-V = Sensitive: 

Vulnerable; S-P = Sensitive: peripheral or naturally rare; ST = state threatened; None: No listing status (Oregon Department of Fish 

and Wildlife 2006).

b FCo: Federal Species of Concern; FT: Federal Threatened; SE: State Endangered; ST: State Threatened; SC: State Candidate; SS: 

State Sensitive; SM: State Monitor; None: No listing status (Washington Department of Fish and Wildlife 2005). 
of primary excavators decrease as a result of nest-site limitations, populations of secondary cavity-nesters also can be

expected to decrease. Past management strategies have

focused only on providing nesting habitat for woodpeckers

(Neitro et al. 1985), but foraging habitat also is critical for

sustaining populations, and many species have different

requirements for fulfilling each function. For example, several cavity-nesting species spend considerable time foraging on live trees, as well as on logs and snags (Weikel and

Hayes 1999). Species specific information on nesting, foraging, and roosting habitat for woodpeckers in various forest types of Oregon and Washington can be found in the

DecAID advisory system discussed below (Mellen et al.

2006; available at http://wwwnotes.fs. fed.us:81/pnw/

DecAID/DecAID.nsf).

The size and decay stage of dead wood are two easily

identifiable characteristics that influence habitat suitability

for individual wildlife species. A large body of literature

indicates that habitat value increases with dead wood diameter. Average diameter of snags used by all wildlife species

for nesting or denning in western Oregon and Washington

exceeds 50 cm (Mellen et al. 2006). The minimum size of

nest trees is determined by the space needed to accommodate an adult inhabitant plus young. When snags of the preferred size are unavailable, smaller snags may be used for

nesting, but this is likely to result in lower reproductive

capacity because fewer eggs and young can be accommodated. Typically, snags selected as nest and roost sites

exceed the minimum size for physical space requirements

because cavities with thicker walls are more secure from

predators, external climate, and probability of stem breakage at the cavity site (O’Connor 1978). In addition, patterns of decay may drive a selection for larger snags as 

nest sites (Bunnell et al. 1999). Snags preferred by cavity

excavators have decaying heartwood and intact sapwood.

Because the time required for heart rot to develop in

conifers such as Douglas-fir is relatively long, trees are

large by the time they acquire pockets of decay suitable for

cavity excavation (Cline 1977). Snag diameter appears to

be a more important factor in nest-site selection than snag

height, although few species select snags < 5 m in height

for nesting (Schreiber and deCalesta 1992.)

Large-diameter logs also offer habitat to more species

than small-diameter logs. The overhang of a log above the

ground increases with diameter, providing important protective cover for small mammals. Small mammals such as

chipmunks (Tamias townsendii) select logs that have larger

average diameters than randomly available wood to use as

travel paths (Waldien et al. 2006). Den sites for large animals (e.g., black bear) are limited to logs of sufficient size

(i.e., > 80 cm). In addition, large logs that retain moisture

serve as refugia for amphibians during periods of drought

(Bartels et al. 1985). Clearly, with regard to dead wood

size, bigger is better because there is no upper limit on 

the size of dead wood used by wildlife, but small snags 

and logs are of limited value as habitat. Furthermore, large

pieces of dead wood, whether standing or down, take

longer to decay than small pieces, and consequently persist

as habitat for longer periods of time.

Snags and logs decay over time as the result of weathering and the activity of decomposing agents, such as fungi

and insects. As dead wood changes structurally with decay,

the associated wildlife species also change. Decay stage of

snags influences the ability of cavity-using species to excavate nest sites. Strong excavators such as red-breasted sapsuckers tend to use hard snags, whereas weak excavators,

such as chickadees and nuthatches, often modify cavities 

in soft, well-decayed snags (Lundquist and Mariani 1991).

Decay stage of logs also influences function as habitat.

Hard logs are more likely to have overhanging cover along

their sides than soft logs, and can offer den sites if they

have hollow interiors. As decay progresses, logs become

more suitable cover for amphibians, and colonization by

fungi and arthropods increases the abundance of food

resources for many wildlife species. Some species use different stages of decay for different purposes. For example,

hairy woodpeckers (Picoides villosus) typically nest in

snags of intermediate decay (Church 1997), but forage

extensively on large-diameter snags in advanced decay

stages (Weikel and Hayes 1999). A diversity of decay

stages of snags and logs is necessary to provide all the

habitat functions of dead wood.

In general, managed forests have a low abundance of

decaying wood relative to natural forests, and the management of woody debris is a major issue in Pacific Northwest

forests (Rose et al. 2001). Past practices have drastically

reduced the quality and quantity of dead wood habitat in

production forests. Intensive management reduces recruitment of dead wood through density management, directly

reduces availability of dead wood habitat through snag

removal for safety and salvage, and severely limits the

upper size ranges of woody debris as a result of short rotations. Compared to levels in unmanaged old-growth, two

rotations of intensive management have been estimated to

reduce the abundance of dead wood by 90 percent (Rose 

et al. 2001). As a result, the large wood that is critical to

maintaining wildlife populations is becoming increasingly

scarce where legacy structures have not been carried forward from rotation harvests. The time it takes to produce

trees of adequate size to support nesting habitat for several

39
species of primary excavators is equivalent to two to three

rotation lengths (Bunnell et al. 1999). If managing habitat

for these key species is a goal, managers could consider

retaining trees at harvest for recruitment of future large

snags. 

Recently revealed information about the functions of

decaying wood as wildlife habitat suggests that current

guidelines for augmenting volumes of woody debris in

managed forests may be insufficient to maintain populations of all species associated with dead wood (Rose et al.

2001, Wilhere 2003). For example, the Oregon Forest

Practices Act Standards for “Wildlife Trees” call for the

retention of five snags or green trees per hectare with a

minimum diameter of 27.5 cm on state lands. However,

five snags per hectare represents only the lowest end of the

natural range of snag densities, and is well below the densities associated with use by cavity-nesting wildlife (at

least 10 snags that are at least 25 cm dbh per hectare;

Hayes and Hagar 2002, Mellen et al. 2006). Furthermore,

the average diameter of snags used by cavity-using species,

> 56 cm (Mellen et al. 2006), is twice the minimum set by

the Oregon Forest Practices Act Standards.

A management strategy for maintaining populations 

of species associated with dead wood should ensure spatial

and temporal continuity of habitat (Hayes and Hagar 2002).

First, existing snags and logs should be maintained during

timber harvest whenever possible. In particular, maintaining large snags likely to endure for long periods might be a

less costly and more effective means of providing habitat

than recruiting smaller snags every rotation. Secondly,

future recruitment of dead wood needs to be planned. A

long-term view is necessary because the lag effect of management on the amounts and types of dead wood may not

appear for 100-200 years, when the last of large legacy

dead wood from previous old-growth is gone. Trees with

defects and of low economic value make good candidates

for retention to become future snags. For safety concerns

and operational considerations, retained trees can be

clumped in patches (Kellogg et al. 2002). The few data that

are available to address the effects of spatial distribution 

of snags (clumped vs. dispersed) on their use by wild-life

suggest that some species (e.g., woodpeckers) may select

snags in patches (Bunnell et al. 1999, Saab and Dudley

1998), but the effect of snag distribution is not understood for most species. Finally, augmenting dead wood

resources may sometimes be necessary. Creating snags

and cavities and supplementing with nest boxes are techniques that have been used. However, these approaches

typically require an intensive investment of time and

money, and have not always been successful in providing

habitat (Bunnell et al. 1999).

Mellen et al. (2006) developed an advisory tool,

DecAID, to help managers evaluate effects of forest conditions and existing or proposed management activities on

organisms that use snags and down wood. The DecAID

database, compiled from a thorough review of the empirical literature on wildlife-dead wood relationships, summarizes habitat associations of wildlife in terms of dead wood

diameter and abundance. Managers can use this information to evaluate the risks and tradeoffs between timber production and wildlife habitat involved at various levels of

dead wood retention. Either the species that would be provided for by retaining various densities and diameters of

coarse woody debris, or the levels of dead wood needed to

provide habitat for species of interest can be determined.

This fine-filter approach to dead wood management is

complemented by a coarse-filter component of the tool:

information on naturally occurring levels of dead wood is

available for guiding decisions about amounts and distribution of dead wood at landscape scale. Another tool available to managers is the Coarse Wood Dynamics model

(Mellen and Ager 2002). Coarse Wood Dynamics model

can be used to project the recruitment, fall rate, and decay

rate of snags and down wood to predict future amounts of

dead wood habitat and guide decisions about green tree

retention and creation of snags and down wood.

Floristic Diversity 

Although it may seem paradoxical, many wildlife

species that occur in Pacific Northwest conifer forests rely

on non-coniferous vegetation within these forests to meet

at least some of their life requirements. Hagar (submitted2)

lists more than 75 forest-dwelling terrestrial vertebrate

species for which an association with non-coniferous vegetation has been documented. Understory shrubs and herbs

provide hiding cover for small mammals and nesting cover

for many shrub- and ground-nesting bird species. Understory

vegetation also provides a diversity of food resources in 

the form of flowers, seeds, fruits, foliage and invertebrates.

Several species of forest-associated hummingbirds rely 

on nectar from flowering plants such as currant (Ribes

spp.), salmonberry (Rubus spectabilis), and Pacific

madrone (Arbutus menziesii) (Patterson 2003, Patterson

40

2 Hagar, J.C. [No date]. Wildlife species associated with non-coniferous vegetation in Pacific Northwest conifer forests: A review. Manuscript 

submitted. Forest Ecology and Management. On file with: USGS Forest & Rangeland Ecosystem Science Center, 777 NW 9th St, Suite 400,

Corvallis, OR 97330.
and Scheuering 2003). The fruit of shrubs such as salal

(Gaultheria shallon), salmonberry, huckleberry (Vaccinium

spp.), and Oregon-grape (Mahonia spp.) provide critical

energy resources for migration and winter survival for many

species of birds (e.g., American robin, (Turdus migratorius), cedar waxwing, (Bombycilla cedrorum), Swainson’s

(Catharus ustulatus) and varied thrushes (Ixoreus naevius))

(Parrish 1997) and small mammals (e.g., chipmunks, squirrels, mice, voles) (Maser et al. 1984). Hardwood trees also

support different food and cover resources than conifers as

a consequence of differences in phenology, reproductive

strategies, leaf palatability, branch structure, and decay

processes (Bunnell et al. 1999, Hayes and Hagar 2002). In

particular, deciduous trees and shrubs support a diverse

assemblage of herbivorous insects such as caterpillars

(Lepidoptera) (Hammond and Miller 1998), an important

prey for many insectivores, especially neotropical migrant

birds. This may explain a consistent pattern of positive 

correlations between abundance and diversity of birds and

abundance and distribution of hardwoods in conifer-dominated landscapes (Morrison and Meslow 1983, Carey et al.

1991, Gilbert and Allwine 1991, Huff and Raley 1991).

Several bird species depend on the presence of a deciduous

component in coniferous forests of the Pacific Northwest.

For example, warbling vireos (Vireo gilvus) are neotropical migrants that rely on caterpillars from deciduous 

trees, particularly red alder (Alnus rubra) (Gardali and

Ballard 2000); MacGillivray’s Warbler (Oporornis tolmiei)

and Wilson’s Warbler (Wilsonia pusilla), both neotropical

migrant species that consume caterpillars, rarely occur in

Oregon Coast Range Douglas-fir stands unless cover of

deciduous shrubs is greater than 35 percent (Hagar 2004).

Hardwood trees also make important contributions to

cavity and snag resources in conifer forests. Pacific madrone

(Raphael 1987), big-leaf maple (Acer macrophyllum), and

Oregon white oak (Quercus garryana) (Gumtow-Farrior

1991) tend to form natural cavities in live trees, providing

a higher density of nesting and roosting opportunities 

for secondary cavity-using species than live conifers. In

several conifer forest types of the Pacific Northwest, a

large proportion of cavity-nesting birds and bat species

select hardwoods as nesting and roosting sites (Bunnell et

al. 1999). Hardwoods may be preferred by many species

because wood properties and decay patterns often result in

softened heartwood that is easily excavated, while the sapwood remains unaffected by decay (Harestad and Keisker

1989). In contrast, sapwood of Douglas-fir snags often

decays by the time heartwood is sufficiently softened for

cavity excavation (Cline et al. 1980). Because of these 

differences, hardwoods can provide suitable cavity sites at

relatively smaller diameters than conifers (Bunnell et al.

1999).

Traditionally, non-coniferous vegetation, particularly

woody shrubs and hardwoods, has not been favored in

management practices aimed at timber production. Early

and sustained conifer dominance in production forests, by

means of vegetation management and planting high densities of tree seedlings at stand initiation, shortens the period

of herb and shrub dominance following harvest, and

reduces the abundance and distribution of understory vegetation and hardwoods in managed forests (Hansen et al.

1991). As a result of management practices that remove

competing vegetation to enhance growth of crop trees,

shrub and hardwood tree cover in the Oregon Coast Range

has declined over the past five decades (Kennedy and Spies

2004). Wildlife species that depend on the resources provided by shrubs and hardwoods are unlikely to persist in

forests where these vegetation components are scarce.

Ideally, management of forests to provide habitat for

species associated with non-coniferous vegetation would

begin early in stand development. Controlling density at 

an early age, before canopy closure, can help to maintain

diverse stand structure throughout the life of a stand, and

can preserve future management options (Tappeiner et al.

2002). Although shrubs may dominate early stages of natural succession, it is unlikely that clear-cutting a forest stand

can be used to immediately create quality habitat for shrubassociated species. The age of shrubs is an important factor

in the habitat offered. Older shrubs have more foliage (i.e.,

provide more cover) and support more epiphytes (Rosso

2000). Furthermore, maximum flower and fruit production

by many shrub species occurs only after a certain stage of

maturity is attained (Harrington et al. 2002; Kerns et al.

2004).

Commercial thinning is a forest management tool that

has the potential to significantly increase habitat availability for shrub-associated wildlife in second-growth conifer

stands (Hayes et al. 1997, Haveri and Carey 2000, Hagar et

al. 2004). By reducing canopy cover and increasing light

availability to the understory, thinning can promote the

development of forest floor vegetation (Tappeiner et al.

1991, Bailey et al. 1998, Thomas et al. 1999). Cover and

productivity of fruit- and seed-bearing understory plants

are influenced by characteristics of forest overstory structure (O’Dea et al. 1995, Klinka et al. 1996, Huffman and

Tappeiner 1997), and may respond positively to thinning

(Minore 1984, Kerns et al. 2003). Increased availability of

mast from understory vegetation in thinned stands may

explain the positive response to thinning of several bird

species that include fruit in their diet (e.g., Swainson’s

thrush, Townsend’s solitaire (Myadestes townsendi), western tanagers (Piranga ludoviciana), and spotted towhees

41
(Pipilo maculates)) (Muir et al. 2002, Hayes et al. 2003,

Hagar et al. 2004). Variable density thinning can be used to

further enhance habitat by increasing spatial heterogeneity

over that typical of stands with evenly spaced trees (Carey

et al. 1999, Carey 2003). Biologically meaningful criteria,

rather than spacing, may be used for selecting leave trees.

For example, selecting leave trees based on tree characteristics such as presence of cavities or large limbs can provide habitat for species associated with complex tree

architecture, as discussed above.

Although single, large deciduous trees or small patches of deciduous vegetation (e.g., 15-20 square meters)

(Morrison 1982) can provide important habitat if they are

not too isolated, a few hardwoods suppressed in the understory are not likely to provide sufficient forage or cover for

most species. Identifying sites where growth of shrubs and

hardwoods minimizes impacts on timber production may

be the most reasonable approach for maintaining associated

species in intensively managed forests. Seeps, wet depressions, small wetlands, and riparian areas may be unproductive for or protected from timber production, but support

deciduous trees and shrubs such as big-leaf maple, red

alder, elderberry (Sambucus spp.), and salmonberry. In

addition, road edges, logging landings, and root rot pockets

provide opportunities for the development of patches of

deciduous growth, particularly red alder. Forest gaps

established to foster the development of large trees with

complex structure (previous section) also are excellent

places to allow growth of shrubs and hardwoods. In fact,

goals for providing habitat associated with large trees,

snags, and floristic diversity could be met simultaneously

in intentionally managed gaps.

CONCLUSIONS

Large trees, large dead wood, and a diversity of vegetation provide critical food and cover resources, collectively

accounting for at least some of the habitat requirements of

most forest wildlife species. Forest stands in which these

elements are present are therefore expected to support a

richer wildlife community than stands representing a single

size class of a single tree species. Furthermore, maintaining

some large trees, large dead wood, and floristic diversity

would likely benefit much more than vertebrate wildlife.

Fungi, lichens, mosses, terrestrial and aquatic invertebrates,

and the ecological processes in which these organisms

function also are affected by forest management that influences these elements (Bunnell et al. 1999). Diversity is

important for maintaining forest function over the longterm (Hooper et al. 2005). 

Production forests can enhance wildlife habitat by

incorporating key elements of structure throughout all

phases of stand management. Managers are already familiar with the silvicultural tools and techniques necessary to

foster structural diversity, such as density management and

selective harvesting. Modifications to the conventional

application of these tools will provide opportunities for

increasing wildlife diversity in production forests. However,

a major challenge will be to decide on the amounts and 

distributions of large wood and non-coniferous habitat elements within stands managed for timber production. Such

decisions will primarily be driven by the goals of each

landowner, and an evaluation of the trade-offs between the

ecological benefits and economic costs of investments in

wildlife habitat. Managers of production forests are keenly

aware of the costs of dedicating space to non-commercial

resources, but many also recognize the benefits of sustaining biodiversity, even though they are not easily translated

into economic metrics and are not always obvious in the

short term. Monitoring is likely to be invaluable for providing information with which to evaluate trade-offs and

demonstrate the effectiveness of alternative management

strategies. Given the implicit goal of production forests to

be managed primarily for timber, they will likely represent

the low end of the range of tree and snag retention and

floristic diversity. Therefore, from a research standpoint,

production forests can serve as a valuable point of reference against which to assess the response of wildlife to a

full range of retention represented at the landscape scale.

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48
1 Timothy B. Harrington is a Research Forester, Pacific Northwest Research Station, USDA Forest Service, 3625 93rd Ave SW, Olympia, WA 98512. 

2 John C. Tappeiner II is Professor Emeritus, Department of Forest Resources, Oregon State University, 280 Peavy Hall, Corvallis, OR 97331.

Managing for Wildlife Habitat in Westside Production Forests

SILVICULTURAL GUIDELINES FOR CREATING 

AND MANAGING WILDLIFE HABITAT

IN WESTSIDE PRODUCTION FORESTS

Timothy B. Harrington1 and John C. Tappeiner II2

INTRODUCTION

Silviculture (from the Latin, silva cultura, or forest 

culture) has been defined as the theory and practice of controlling forest establishment, composition, structure, and

growth (Smith et al. 1997). It encompasses systems for

regenerating forests as well as specific treatments for tending them. Much of the forest land west of the Cascade

Mountain crest (i.e., the Westside) is dominated by relatively young (< 100 years old), naturally-regenerated or

planted stands of coast Douglas-fir (Pseudotsuga menziesii

(Mirb.) Franco var. menziesii). For most of the 20th century,

traditional silvicultural practices in this region were focused

primarily on managing forests for wood products. Today’s

broader view of silviculture for Westside production forests

includes managing portions or entire stands for wildlife

habitat and other ecological services.

49

Wildlife habitat has been defined as “the sum total of

the environmental factors – food, cover, and water – that 

a given species of animal needs to survive and reproduce”

(Trefethen 1964). Specific forest stand features that can be

managed to improve wildlife habitat include density and

height of overstory conifers and mid-story hardwoods,

cover and height of shrubs, abundance of standing and

down woody debris (Hagar et al. 1996), and diversity and

abundance of herbaceous species (Hanley et al. 2006, Deal

et al. 2004). In this paper we discuss some of the theory

behind treatments used to create and sustain habitat and

provide general guidelines for their application in Westside

production forests. Topics include how to design new stands

following timber harvest, how to establish new trees and

shrubs in existing stands, and how to thin existing stands 

to create old-forest structure.

ABSTRACT

Conventional silvicultural treatments (planting, competition control, and thinning) are being considered as techniques 

for creating and managing wildlife habitat in Westside production forests of the Pacific Northwest. These methods can be

used to diversify forest structure (i.e., species, size, age, and spatial arrangement of trees and other vegetation) and facilitate

development of old-forest characteristics. Pre-treatment planning is essential for identifying management intensities appropriate for a given area, retaining existing structural elements, or providing conditions for development of new structural elements. Hardwoods and shrubs from the pre-harvest stand can be managed for habitat within a new conifer plantation if they

are given sufficient growing space. Conifer seedlings can be established successfully under low overstory densities, but

their growth can be strongly reduced by competition from overstory trees and understory vegetation. Combining thinning

and moderate soil disturbance during harvest will create favorable conditions for germination, sprouting, and rhizome

expansion of understory species. Thinning will result in a heterogeneous forest structure if it is applied with uneven spacing

and retains minor species, standing dead trees, and pockets of tree regeneration. Site-specific characteristics, such as rootrot pockets, soil and topographic variability, and potential for wind damage, should be considered when designing a thinning treatment. The inherent productivity of a forest site will determine the rate at which a diverse stand structure will

develop; however, some characteristics of old forests (large cavities in snags, high abundance of coarse woody debris, and

nesting platforms on large limbs) will take decades to develop.
DESIGNING NEW STANDS

Pre-harvest planning is essential to creating the desired

structure of a new forest stand because opportunities for

retention or creation of specific habitat features often exist

prior to or immediately after harvest including:

• forage (mast, browse, or grazing) species

• nest sites

• snags (standing dead trees) and green trees

• shrub cover

• down wood

For example, selected conifers, hardwoods, or shrubs

can be protected during logging and retained into the next

stand, providing habitat that otherwise would have taken

decades to develop as seedlings or sprouts. Reasons for

protecting such vegetation include their ability to provide

nesting sites, forage, and cover during the period of establishing a new stand of conifers. Table 1 provides examples

of native woody plants that provide important habitat values to Westside wildlife. Wender et al. (2004) found that

plant size and age and overstory density were the primary

determinants of flowering and fruiting for nine Westside

shrub species. This indicates that the largest and oldest

individual plants and those growing under low overstory

densities have the greatest potential for providing forage

for wildlife.

To focus regeneration treatments appropriately, areas

within the future stand can be designated for wood production only, a combination of wood production and wildlife

habitat, and habitat only. In this way, treatments such as

competing vegetation control and fertilization would be

applied to the areas where they most effectively encourage

wood production. Some herbicide treatments used in site

preparation and competition release (e.g., imazapyr and

hexazinone) have been shown to improve wildlife habitat

in the Southern U.S. by favoring blackberry (Rubus spp.),

huckleberry (Vaccinium spp.), and legume species, and by

reducing vegetation height and promoting sprouting and

succulent growth of woody species (Miller and Miller

2004). Mechanical crushing or cutting treatments also can

be used to reduce height and stimulate succulent growth of

browse species. Piles of woody debris typically left after

timber harvest can be retained to provide cover in selected

areas within the stand. However, rodent and rabbit populations are likely to increase in and around these debris accumulations; therefore, such habitat should be reserved for

areas not designated primarily for wood production

because of potential animal damage to conifer seedlings.

Snags provide critical habitat for many species of birds

and small mammals. The Washington State Department of

Natural Resources (2006) provides the following guidelines

for creating snags from living trees, especially those with

broken tops or large branches:

• For safety, locate snags away from trails, roads, buildings, and other structures. Guidelines for selecting 

reserve trees and snags should be consulted prior to 

timber harvest (e.g., Washington State Department of

Labor and Industries 2006).

• Conifer snags last longer than hardwood snags; 

selected trees should have a stem diameter of at least 

14 in to provide nest sites and for increased longevity.

• Trees should be topped or girdled at or above the first

whorl of branches, at least 14 ft above ground and, 

ideally, much higher. Smaller trees or stumps at least 

3 ft tall may be useful for some cavity nesters.

• Following are desirable features of snags:

¡ A jagged top decays faster, making it more useable 

for some wildlife species.

¡ Artificial cavities (at least 6 in deep and 4 in high)

in newly-created snags also accelerate decay.

¡ Large branches (2 ft long or more) provide foraging habitat.

¡ Roosting slits (angled upward at least 8 in deep 

and 2 in wide) are used by bats and some birds.

If new seedlings or sprouts of hardwoods and shrubs 

are to be grown to maturity within a conifer plantation, an

unplanted buffer area (two or more planting rows wide)

should be provided around them to ensure adequate growing space for their survival. Conifer seedlings designated

for wood production should not be planted in the buffer

area or otherwise they may succumb to mortality from

overtopping (fig. 1).

ESTABLISHING UNDERSTORY

CONIFERS

Conifer stands in Westside production forests often have 

a relatively dense, single-layered canopy structure. Such

structures can be diversified by creating or accelerating

development of additional canopy layers either by promoting existing understory trees or by planting tree seedlings.

Using existing understory trees is easier and cheaper than

planting seedlings, but planting may be necessary if establishing selected species is the goal.

Planted seedlings of most Westside conifer species will

survive under a wide range of overstory densities, although

their growth will be slowed greatly relative to full sunlight

conditions. Douglas-fir is relatively intolerant of shade, and

50
51

Table 1—Common woody plants native to Westside forests of the Pacific Northwest that provide habitat 

values for wildlife (USDA Natural Resources Conservation Service 2006)

Common name Scientific name Habitat values

bigleaf maple Acer macrophyllum Pursh browse, cover

bitter cherry Prunus emarginata (Dougl. ex Hook.) D. Dietr. mast, browse

black hawthorn Crataegus douglasii Lindl. mast, browse

California black oak Quercus kelloggii Newberry mast, browse

California hazelnut Corylus cornuta Marh. var. californica (A. DC.) Sharp mast, cover

cascara Rhamnus purshiana DC. browse, cover

ceanothus Ceanothus spp. browse, cover

cottonwood Populus spp. browse

Douglas-fir Pseudotsuga menziesii (Mirb.) Franco browse, cover

elderberry Sambucus spp. mast, browse, cover

huckleberry Vaccinium spp. mast, browse, cover

Oregon ash Fraxinus latifolia Benth. browse

Oregon white oak Quercus garryana Dougl. mast, browse

Pacific madrone Arbutus menziesii Pursh mast

red alder Alnus rubra Bong. browse

western redcedar Thuja plicata Donn ex D. Don browse

red-osier dogwood Cornus sericea L. mast, browse, cover

salal Gaultheria shallon Pursh mast, browse, cover

salmonberry Rubus spectabilis Pursh mast, browse, cover

Saskatoon serviceberry Amelanchier alnifolia (Nutt.) Nutt. ex M. Roemer mast, browse, cover

tanoak Lithocarpus densiflorus (Hook. & Arn.) Rehd. mast, cover

trailing blackberry Rubus ursinus Cham. & Schlecht. mast, browse

western mountain ash Sorbus sitchensis M. Roemer mast

willow Salix spp. browse, cover

woods rose Rosa woodsii Lindl. browse

vine maple Acer circinatum Pursh. mast, browse, cover

Figure 1—A 7-year-old sprout clump of bigleaf maple (right) that has competed with and killed all of the slower growing Douglas-fir

seedlings under its canopy. Photo by Robert G. Wagner
therefore reasonable rates of seedling growth require much

lower overstory densities than required by seedlings of

western hemlock (Tsuga heterophylla (Raf.) Sarg.) or western redcedar (Thuja plicata Donn ex D. Don). Douglas-fir

seedlings need greater than 20 percent of full sunlight to

survive, at least 40 percent for continued morphological

development (Mailly and Kimmins 1997), and full sunlight

for maximum growth rates (Drever and Lertzman 2001).

Western redcedar seedlings require only 10 percent of full

sunlight to survive (Wang et al. 1994), and their maximum

growth rates can occur at only 30 percent of full sunlight

(Drever and Lertzman 2001). 

If the goal is to manage understory conifers so they 

provide a second story for habitat and ultimately become

mature crop trees, a relatively low overstory density is recommended. Assuming a relative density of 65 for a fullystocked stand of Douglas-fir (Curtis 1982), overstory

densities of 40 percent of full stocking (thinned stands)

reduced fifth-year stem volume of Douglas-fir, western

hemlock, and western redcedar seedlings by 87, 85, and 

76 percent, respectively, relative to seedlings growing in

clearcuts (fig. 2a) (Harrington 2006). Overstory densities 

of 16 percent of full stocking (shelterwoods) reduced stem

volume of Douglas-fir and western hemlock by 46 and 30

percent relative to seedlings growing in clearcuts, respectively; however, redcedar attained its maximum stem volume in shelterwoods. Brandeis et al. (2001) observed

similar reductions in growth of under-planted seedlings of

western hemlock, western redcedar, and grand fir (Abies

grandis (Dougl. ex D. Don) Lindl.) with increasing overstory density. Overall, these results suggest that overstory

densities should not exceed 20 percent of full stocking if

reasonable rates of development are expected for conifer

seedlings. 

If conifer seedlings are to be planted near overstory

trees, it may be necessary to locate them so that overstory

trees: (1) do not compete excessively with them, and (2)

can be har-vested without severely damaging them. Overstory trees are effective competitors for soil water and

nitrogen, and even low overstory densities can strongly

reduce availabi-lity of these resources (Prescott 1997,

Harrington 2006). Overstory density can be managed via

either one intensive removal (i.e., leaving < 10 percent of

full stocking) or several removals (i.e., each leaving 20

percent of full stocking) to maintain the vigor of understory

conifers over time. 

A dense cover of shrub and herbaceous vegetation will

provide further competition for conifer seedlings in what is

already a highly-competitive understory environment. In

such conditions, it may be necessary to reduce height and

cover of competing vegetation to provide adequate availability of light and soil water to support seedling development. Some of the reduction in understory competition can

be accomplished during logging; however, in other cases

manual cutting (to reduce vegetation height) or herbicide

application (to reduce vegetation cover) will be needed to

create viable planting spots and to ensure that the seedlings

will survive and grow at reasonable rates. Regardless of

overstory density, controlling competing vegetation around

individual seedlings doubled the fifth-year stem volume of

Douglas-fir and redcedar, while it tripled the volume of

western hemlock (fig. 2b) (Harrington 2006). Brandeis et

al. (2001) observed similar increases in growth of underplanted seedlings of western hemlock and grand fir following control of competing vegetation. Salal is especially

competitive with western hemlock (Mallik and Prescott

2001, Harrington 2006) probably because the fine roots of

both species are concentrated in the upper forest floor

(Bennett et al. 2002).

In mesic environments near the Pacific Coast or at 

moderate elevations, reductions in overstory density can

stimulate development of excess accumulations of conifer

regeneration, especially western hemlock (Deal and Farr

1994). Although desirable at lower densities, these seedlings can form a dense canopy layer that prevents or suppresses development of other understory species important

to wildlife. Drastic reduction in density of hemlock regeneration may be necessary to maintain a diverse community

of herbaceous species and promote germination of shrubs.

Such density reductions can be accomplished via moderate

soil disturbance during timber harvest or a subsequent 

pre-commercial thinning.

Animal damage, particularly browsing on Douglas-fir

and western redcedar by black-tailed deer (Odocoileus

hemionus columbianus Richardson) and Roosevelt elk

(Cervus canadensis roosevelti Merriam) (Brandeis et al.

2002), can further delay conifer seedling development.

Frequency of seedlings browsed can increase as redcedar

becomes increasingly visible either from reductions in density of overstory trees or understory vegetation (Harrington

2006). Deer browse on western hemlock is rare; however,

seedlings of most Westside conifers are susceptible to

antler scraping by deer and elk. Gaps in understory vegetation created by mountain beaver (Aplodontia rufa pacifica

Merriam) will contribute to the structural diversity of new

conifer stands. 

52
53

Figure 2—Stem volume of western hemlock, Douglas-fir, and western redcedar seedlings five years 

after planting in clearcuts, shelterwoods, or thinned stands with 100, 50, or 0 ft2 areas of competing 

vegetation control around each seedling (Harrington 2006). Average responses to overstory density 

and competing vegetation control are shown in (a) and (b), respectively.

PROMOTING UNDERSTORY

VEGETATION

During the past decade, experiments and surveys were

initiated to quantify the effects of thinning on forest structure (Hayes et al. 1997, Bailey and Tappeiner 1998). By

increasing availability of light in the understory, and perhaps

also belowground resources, thinning facilitates increases

in seed production and vegetative growth of existing understory vegetation. Species can expand their site occupancy

through spread of rhizomes (e.g., salal, trailing blackberry,

and salmonberry) or layering (rooting) of prostrate stems

(e.g., vine maple). 

When thinning is combined with a moderate intensity

of soil disturbance, such as from skidding of logs during

timber harvest, it creates germination substrates that facilitate seedling regeneration of woody and herbaceous

species. Increases in seedling germination and survival of

both shade-tolerant species (e.g., salal, vine maple, huckleberry, tanoak, and bigleaf maple) and shade-intolerant

species (e.g., red alder, salmonberry, and Pacific madrone)
have been observed after thinning Douglas-fir stands

(Haeussler et al. 1995, Huffman et al. 1994, Huffman and

Tappeiner 1997, Tappeiner et al. 1986, Tappeiner and

Zasada 1993). However, development of shrub cover and

wildlife forage occurs much more rapidly from sprouts,

and thus, this method of regeneration is likely to be preferred over that of seedlings.

Thinning intensity and pattern will influence the spatial

distribution of woody debris and soil disturbance. For

example, in the Demonstration of Ecosystem Management

Options (DEMO) study, depth and cover of debris were

greater at the highest thinning intensity and in aggregated

versus dispersed retentions of overstory trees (Halpern and

McKenzie 2001). Reduced abundances of late-seral herbaceous species observed soon after harvest probably were

associated with the patterns of debris accumulation and soil

disturbance that resulted from thinning (Aubry et al. 2004). 

USING THINNING TO CREATE 

OLD-FOREST STRUCTURE

General Principles

The high productivity of many Westside forests enables

managers to grow structural characteristics of old forests

(e.g., large trees, standing and down woody debris, a multilayered and spatially heterogeneous canopy, and a high

diversity of plant species) in a much shorter time interval

than occurs through typical patterns of forest succession.

Prescriptions for managing young stands to achieve oldforest characteristics generally call for thinning of overstory trees because most young stands were planted at high

densities to grow high yields of wood. In conventional 

thinning, the smaller trees are removed (thinning from

below) at a relatively uniform spacing to enable the largest,

most vigorous trees to close the stand canopy and continue

their rapid growth. Thinning for old-forest characteristics

will likely remove large and small trees in an irregular pattern to promote not only the growth of large trees, but also

a diverse tree, or shrub understory. There has been relatively little long-term experience in thinning to achieve oldforest characteristics; however, following are some

principles from research and observation that should apply:

• Maintain large trees from the previous stand. These trees

are apt to have large limbs, cavities, and rough bark that

are important habitat for wildlife. In addition they may be

a source of propagules for lichens, mosses, and mycorrhizae to enable regeneration of these species in the new

stand. 

• Protect minor species. Certain tree species may occur

infrequently, such as western redcedar, western hemlock,

yew (Taxus brevifolia Nutt.), Sitka spruce (Picea sitchensis (Bong.) Carr.), and Engelmann spruce (Picea engelmannii Parry ex Engelm.). Retaining these trees could

provide a seed source that enables the species to increase

their numbers on the site and contribute to species diversity and stand heterogeneity.

• Create seedbeds for establishment of understory plants.

Some disturbance to the forest floor (e.g., skidding of

logs during harvest) can provide a seed bed to aid 

establishment of understory woody and herbaceous

plants.

• Control understory competition when it becomes 

excessive. A dense understory of shrubs like salal, 

vine maple, salmonberry, huckleberry, or blackberry, 

or hardwoods like bigleaf maple, Pacific madrone, or

tanoak can interfere with seedling establishment of

conifers and other species. In these cases it might 

be necessary to control shrub and hardwood density 

and plant conifer seedlings to establish a multi-storied

stand.

• Manage some trees or parts of stands at low density.

Large old-growth trees generally grew quite rapidly 

when they were young, and their diameters at 200 to 

> 300 years were correlated with their size and growth 

rates when they were 50 years old (Tappeiner et al. 

1997, Poage and Tappeiner 2002). This research 

suggests that some trees should be grown at low 

density when they are young and the tree density 

around them kept low for several decades. This can be

accomplished by thinning around selected large trees –

those that have the most rapid growth – in order to provide space, maintain large crowns and continue rapid

diameter growth.

• Use thinning to favor patches of regeneration. 

Thinning can be concentrated around patches of 

advanced tree regeneration to facilitate development 

of multi-storied stands.

• Allocate some trees for production of woody debris. 

In stands where there are few large snags or logs on 

the forest floor, it may be necessary to grow large trees 

to kill for snags or logs or to ensure there are enough

large trees to make snags and logs from natural agents

(wind, insects and root pathogens) and to maintain a 

large tree component in the overstory. Risk of an outbreak of Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins) from such treatments should be 

54
minimal (Ross et al. 2006). For specific guidelines on

managing stands to produce appropriate abundances 

and sizes of woody debris, consult the DecAID Wood

Advisor (Mellen et al. 2003). 

• Relatively dense overstories favor some herbaceous

species. Maintaining dense patches of overstory trees 

or excessive conifer regeneration may retard establishment of a dense cover of shrubs and provide sites for 

late-seral herbaceous plants (Lindh 2005).

• Old trees will respond positively to thinning. Age or 

size of conifer trees is not an obstacle to thinning or 

use of prescribed fire. Very large (> 40 in diameter), 

old (> 200 years) trees can respond positively to thinning (Latham and Tappeiner 2002).

• Create space for development of hardwoods. Height

growth of conifers at ages of 50 years or more is 

usually greater than that of hardwoods. As hardwoods

become overtopped and encroached upon by neighboring conifers, their crowns will decline in size and vigor

(fig. 3). Therefore, reducing density of conifer trees

around hardwoods will enable hardwoods to maintain

vigorous, full crowns that can produce mast for wildlife, provide cavities for nesting, and support bryophyte and lichen populations. A heavy thinning around 

0.25- to 0.6-acre patches of hardwoods will ensure 

they remain a viable part of a vigorous conifer stand.

When used according to these principles, thinning specifications will be spatially variable throughout a stand. For

example minor species, opportunities to release seedlings

and saplings, and trees remaining from the previous stand,

may occur sporadically. Similarly large, rapidly growing

trees usually do not occur in a regular pattern due to differences in stand density and site productivity. If the focus is

on the objectives stated above, then parts of the stand might

not be thinned or would only be lightly thinned. Given this

variability, flexibility in prescription writing and application

is advised, since it is unlikely that all objectives will be

accomplished on each acre. For example if the goal is to

grow 30 large trees per acre, the range in per-acre density

might be > 40 trees in some areas and < 10 trees in other

areas with an average of 30 trees over an area of five to ten

55

Figure 3—A dense 23-year-old Douglas-fir plantation that has encroached upon and suppressed a slower growing multi-stemmed tree of

bigleaf maple. Photo by Timothy B. Harrington
56

acres. Variable density thinning, a recent approach for conserving biodiversity while encouraging development of

old-forest structure in young, fully-stocked stands of

Douglas-fir, creates gaps and retains uncut areas within a

stand matrix that is thinned in a conventional manner

(Carey and Curtis 1996, Harrington et al. 2005).

Forest- or site-specific information may be needed upon

which to base treatments to accelerate development of oldforest structure. Most of this information can be collected

at the local forest type, or plant association level and it

includes:

• Sizes, densities, and species composition of large overstory trees and second-story trees needed to produce

multi-storied stands.

• The stand density or gap size needed to grow understory trees.

• Sizes and densities of snags and logs on the forest 

floor. This should help determine numbers of trees to

leave after thinning.

• The effects of snow, wind, insects, and pathogens on 

tree mortality and the associated production of snags, 

logs on the forest floor, and cavities for nesting.

Site productivity and potential for tree growth vary considerably throughout the Westside; therefore age alone is

not a good descriptor of a stand. On low productivity sites,

stands can take over 100 years to reach the same stage of

development that they could reach in 50 years on productive sites.

There are site-specific variables that affect stand development. Root diseases that kill overstory trees are widespread in Westside forests; however, their effects on stand

development vary substantially within and among stands,

killing Douglas-fir and favoring species like western hemlock, western redcedar, and vine maple in some stands.

Swiss needle cast, a foliage disease caused by the fungus,

Phaeocryptopus gaeumannii, is currently epidemic in parts

of northwestern Oregon, and appears to be nearly eliminating Douglas-fir from some stands and converting them to

western hemlock and western redcedar. This disease clearly

has a major impact on stand development and the potential

for infected stands to achieve old-forest characteristics. The

effects of pathogens, insects, and wind can be beneficial

especially in older stands as they make snags, logs on the

forest floor, and nesting cavities. However, their potential

effects need to be considered in young stands, because they

can have major impacts on stand development.

Past management has varied across the region, affecting

the potential for development of old-forest characteristics.

Some stands have been planted at low densities or thinned

at early ages, and therefore, have the potential for rapid

development of large trees and establishment of an understory. However, tree growth rates are slow in stands that

have grown at high density for several decades and there

may be little understory present. Also trees in high density

stands will require more time to respond to thinning than

trees in less dense stands, and they may be susceptible to

damage by wind, snow, and ice until their stem diameters

increase relative to height. Older stands (> 30 years) that

have been thinned often have a conifer understory established that can be released by subsequent thinnings to produce multi-storied stands. Species composition can be

affected during reforestation, competition control, and early

thinning. For example, stands reforested with mixed species

will develop differently than those that have had most

hardwoods and shrubs removed to reduce competition with

conifers.

Tree and Stand Responses to Thinning

Thinning affects both the growth of individual trees and

development of the stand. Thinning reduces the leaf area of

the canopy, thereby increasing light and often availability

of soil water and nutrients. Reduced competition for these

resources increases the growth of overstory trees and the

abundance of understory plants. Site resources become

available to fewer trees and shrubs enabling them to

increase their growth rates.

A major response of trees to thinning is the maintenance

or increase in crown size. Increased light or space among

trees enables the lower branches on the crown to remain

alive and not be shaded out by adjacent trees. Thus, tree

crowns expand in width as branches grow longer and thicker. Tree crown length increases as low branches remain

alive and height growth continues. Crown expansion also

occurs via epicormic branching (i.e., sprouting of new

branches below the crown as the tree stem is exposed to

increased light from removal of neighboring trees). Epicormic branching is common in Douglas-fir and often forms

fan-like branches that are important roosting structures for

birds and arboreal rodents. 

Growth in the stem and branches of trees is accelerated by thinning because foliage density or leaf area within

the crown increases and crown length is maintained or

increased. This increase in leaf area enables trees to increase

their photosynthesis; consequently, they have the resources

to increase stem and branch diameter or volume. As crown
length increases, stem diameter growth is maintained or

increased on the lower part of the stem. Thus, the tree’s

stem becomes more tapered and consequently more resistant to windthrow or stem breakage.

An increase in diameter may occur within three to five

years after thinning depending upon stand density and tree

growth before thinning. If trees are growing slowly an

obvious increase in ring width may occur. If trees are

growing vigorously, thinning may maintain their rate of

growth but there will be no obvious increase. Repeated

measurements of stem diameter or increment coring will 

be needed to evaluate stem growth responses to thinning.

Short-term effects of thinning on crown size and density

are more difficult to measure or observe. With variable

density thinning, growth will be greater for trees near gaps

or along skid trails than for those in uncut areas

(Harrington et al. 2005).

Important Caveats to Consider

Planning a program of young stand management is an

important part of the development of old-forest characteristics. Currently a very small percentage of the young stands

are being thinned. It appears that many stands will reach

maturity and final harvest without being thinned. Forest

managers may choose the option of either: (a) treating very

few stands with thorough, one-time treatments and severe

reduction in density, or (b) conducting a light thinning in

many stands to begin the process of old-forest development

and develop options for future treatments. For example the

initial treatment might enable the establishment of trees in

the understory and begin the development of large trees. A

second thinning would release the understory trees and provide for the continued growth of large trees. A caution in

thinning approach (a) (above) might be that a single heavy

thinning could establish a dense shrub (or conifer) understory, making it difficult for a diverse understory to develop. Thinning around bigleaf maple, Pacific madrone, or

California black oak may be needed to maintain or develop

them for habitat. As conifers overtop them, hardwoods lose

their ability to produce mast and large limbs and eventually

may die from competitive effects of shade (fig. 3). 

It is important to realize that it takes time to develop

old-forest attributes. Probably, the most obvious effects 

of thinning are an increase in understory density and the

establishment and growth of seedlings in the understory.

The early increase in understory abundance can be important to wildlife species. A diverse shrub understory supports insect populations that are prey for a variety of birds.

Increased mast production can benefit birds and small

mammals. Browse for ungulates may also be an important

early result. However, some attributes of old forests, such

as large cavities, nesting platforms on large limbs, or a high

abundance of coarse woody debris, will take decades to

develop. 

ACKNOWLEDGMENTS

Thanks to Liz Cole, Bob Deal, and Gretchen Nicholas

for their helpful manuscript reviews.

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structural development in 40- to 100- year-old Douglasfir stands in western Oregon. Forest Ecology and

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Brandeis, T.J.; Newton, M.; Cole, E.C. 2002. Biotic 

injuries on conifer seedlings planted in forest understory

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stands of western hemlock and Sitka spruce in southeast

Alaska. Canadian Journal of Forest Research. 

24: 976-984. 

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D.V. 2004. Stand dynamics of mixed red alder-conifer

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nutrients. Canadian Journal of Forest Research. 31:

2124-2133.

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Germination and first-year survival of red alder

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Bird communities in commercially thinned and

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Halpern, C.B.; McKenzie, D. 2001. Disturbance and 

post-harvest ground conditions in a structural retention

experiment. Forest Ecology and Management. 154: 

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Relations between red alder (Alnus rubra Bong.) and

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Forest Research. 36: 738-748.

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Douglas-fir, western hemlock, and western redcedar

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36: 2439-2453. 

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J.C.; Kellogg, L.D.; Bailey, J.D. 1997. Wildlife

response to thinning young forests in the Pacific

Northwest. Journal of Forestry. 95: 28-33.

Huffman, D.W.; Tappeiner, J.C.; Zasada, J.C. 1994. 

Regeneration of salal in the central Coast Range forests

of Oregon. Canadian Journal of Botany. 72: 39-51. 

Huffman, D.W.; Tappeiner, J.C. 1997. Clonal expansion 

and seedling recruitment of Oregon-grape (Berberis

nervosa) in Douglas-fir (Pseudotsuga menziesii) forests:

comparison with salal (Gaultheria shallon). Canadian

Journal of Forest Research. 27: 1788-1793.

Latham, P.; Tappeiner, J.C. 2002. Response of oldgrowth conifers to reduction in stand density in western

Oregon forests. Tree Physiology. 22: 137-146.

Lindh, B. 2005. Effects of conifer basal area on understory 

herb presence, abundance, and flowering in a secondgrowth Douglas-fir forest. Canadian Journal of Forest

Research. 35: 938-948. 

Mailly, D.; Kimmins, J.P. 1997. Growth of Pseudotsuga

menziesii and Tsuga heterophylla seedlings along a light

gradient: resource allocation and morphological acclimation. Canadian Journal of Botany. 75: 1424-1435.

Mallik, A.U.; Prescott, C.E. 2001. Growth inhibitory 

effects of salal on western hemlock and western red

cedar. Agronomy Journal. 93: 85-92.

Mellen, K.; Marcot, B.G.; Ohmann, J.L.; Waddell, 

K.L.; Livingston, S.A.; Willhite, E.A.; Hostetler,

B.B.; Ogden, C.; Dreisbach, T. 2003. DecAID, the

Decayed Wood Advisor for managing snags, partially

dead trees, and down wood for biodiversity in forests 

of Washington and Oregon. Version 2.0. Portland, OR:

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2006).

Miller, K.V.; Miller, J.H. 2004. Forestry herbicide influences on biodiversity and wildlife habitat in southern

forests. Wildlife Society Bulletin. 32(4): 1049-1060.

Poage, N.J.; Tappeiner, J.C. 2002. Long-term patterns of 

diameter and basal area growth of old-growth Douglasfir trees in western Oregon. Canadian Journal of Forest

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Prescott, C.E. 1997. Effects of clearcutting and alternative 

silvicultural systems on rates of decomposition and

nitrogen mineralization in a coastal montane coniferous

forest. Forest Ecology and Management. 95: 253-260.

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the Oregon Coast Range. Western Journal of Applied

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1997. The practice of silviculture: applied forest 

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Survival of tanoak and Pacific madrone seedlings in

forests of southwestern Oregon. New Forests. 1: 43-55.

Tappeiner, J.C.; Zasada, J.C. 1993. Establishment of 

salmonberry, salal, vine maple and bigleaf maple

seedlings. Canadian Journal of Forest Research. 23:

1175-1780.

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Bailey, J.D. 1997. Density, ages, and growth rates in

old-growth and young-growth forests in coastal Oregon.

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Thuja plicata seedlings along a light gradient. Canadian

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59
This page is intentionally left blank.
1 Jim Bottorff is the Forest Stewardship Program Wildlife Biologist in the Small Forest Landowners Office, Washington Department of Natural

Resources, 1111 Washington St SE, P.O. Box 47012, Olympia, WA 98504-7012.

Managing for Wildlife Habitat in Westside Production Forests

WILDLIFE HABITAT MANAGEMENT PRACTICES 

ON PRIVATE NON-INDUSTRIAL FORESTLANDS

Jim Bottorff 1

CHARACTERISTICS OF FAMILY

FOREST OWNERS

Family forest owners come from very diverse backgrounds and levels of experience but usually unrelated to

forestry. They have very wide ranges of management objectives and reasons for acquiring and/or retaining ownership

of forestland. Creighton et al. (2002) reported a wide range

of characteristics. Fourteen percent owned less than 10

acres while 23 percent owned more than 100 acres. The

median ownership from their surveys was just less than 40

ABSTRACT

Non-industrial private forestlands (NIPF), also known as family-owned forests or family forests, represent one of 

the bigger challenges facing forestland managers (including timber harvesters, foresters, and forest wildlife biologists) in

Washington State and probably beyond. Those practicing traditional forestry (timber harvest based revenue production) may

be particularly challenged, and professionally rewarded, when working with NIPF landowners due to the combination of

diverse past site management and highly variable landowner objectives. Many of these objectives may or may not be related

to forest management and income production (Gootee 2004). One of the biggest impediments to effective wildlife habitat

management is getting the practicing forestland managers to understand the objectives and recognize opportunities to protect, enhance, and create wildlife habitat. There may be a professional/personal conflict with accepting and implementing

landowner wildlife objectives as co-equal with timber management and especially as a primary objective. Perkey (1989)

stated it succinctly: “those of us involved with management of the private non-industrial forest must learn to use our silvicultural knowledge effectively to accomplish non-silvicultural landowner objectives, including wildlife habitat management.” These challenges are continuing to be met through the Forest Stewardship Program (FSP) now within the Small

Forest Landowner Office (SFLO) of the Washington State Department of Natural Resources (DNR). The wildlife goal of

the FSP has been to implement practices that protect, enhance, and even create wildlife habitat in conjunction with standard

timber management activities and done in such a way that is cost effective for the landowner and easily learned by the onsite forest worker. Most of the techniques are based on well-documented long-term observations and emerging science. For

effective development and implementation of wildlife habitat practices it is essential to understand the background and

motivation of these forestland owners and the relationship of these forested parcels within the forested landscape.

KEYWORDS: Non-industrial private forestlands, habitat management practices, wildlife trees, coarse woody debris.

61

acres. Only one-half the owners lived on their land and for

those that did not, about one-half lived more than 50 miles

distance. The NIPF owner tends to be well educated: three

percent have not completed high school; whereas, well over

one-half have at least some college education including 17

percent that have attended graduate schools. They also tend

to be older than the general populace: over one-half are

older than 55 and seven percent are under 40 years of age.

It should be noted that this advancing age scenario directly

influences wildlife habitat practices they are interested in

and willing to implement. Although a whole host of longrange practices that will enhance numerous generations of
62

wildlife are available, the visible benefits are too far into

the future to warrant much landowner interest.

Their reasons for owning forestland are probably the

most revealing characteristic that creates challenges for

forestland managers. When given choices to rate as important reasons for land ownership over 80 percent cited providing wildlife habitat. Just less than one-half listed income

from timber harvest as very to somewhat important. 

CHARACTERISTICS, LOCATION, 

AND SIGNIFICANCE OF NIPF

About 59 percent of forestland in the United States is

family-owned (Johnson 1997) while family forests comprise about 19 percent (about 2.6 million acres) of the total

forestland in Washington State (USDA 2000). Due to

Endangered Species Act issues and public expectations;

timber harvest on public lands has declined significantly.

Private lands have taken up the slack with family-owned

forests (with only 19 percent of the ownership) accounting

for almost 30 percent of the harvest by volume (WDNR

1999). 

Family forests are often located in the more fertile

lowlands with high site potential and productivity. These

lands are also subject to increasing development pressures

(Johnson 1997). Almost 90 percent of NIPF land in

Washington is located below 3,000 feet elevation and almost

one-half is below 1,500 feet elevation (WDNR 2002). 

WILDLIFE HABITAT PRACTICES

Ideally, management practices should be applied to

intact ecosystems or at least to identifiable landscapes to

benefit the greatest number of species over time (Urban et

al. 1987). Because of the ownership characteristics, familyowned forests must be managed as ‘patches’ of forested

wildlife habitat within and not across the landscape. Therefore, management practices must fit into individual stand

management considerations, and as stated above, they must

be cost-effective and easily applied. The Forest Stewardship

Program has also strived to recommend those practices that

will benefit the greatest number of species within the listed

constraints. The most common practices then are as follows.

Snags and Wildlife Trees

These include both snags (dead trees) and wildlife

trees (those with substantial defect such as broken tops,

multiple tops, dying tops, stem damage and decay, numerous large dead branches, or other forms of obvious vigor

decline). This is one of the most, if not the most important

habitat feature in managed forests in terms of the number

of species it serves (Neitro et al. 1985). Existing Forest

Practice Act requirements are insufficient in capturing the

amount of this structural component for all but an absolute

minimum number of dependent species and then it is

dependent on assuring that the appropriate size, type, and

distribution is achieved. (Zarnowitz and Manuwal 1985).

Several methods are available to protect, enhance, or even

create this habitat type as a component of food, shelter, and

cover for almost 100 species of snag-dependent wildlife.

These include:

• identification of suitable snags and wildlife trees for

retention in every stand age to be managed,

• enhancement and creation of snags of various heights 

and diameters,

• high-stumping (stumps at least 3 ft in height),

• appropriate numbers and distribution of snags and

wildlife trees.

Coarse Woody Debris

Like snags, coarse woody debris is essential to a broad

array of wildlife species and is a regulated resource as well.

It is an easy and effective resource to manage if the needs

of dependent wildlife species are considered. Coarse

woody debris can be created and/or retained in stands of 

all size and age classes. Management of this resource

includes:

• identification and distribution of suitable pieces for

retention,

• creation and distribution of suitable pieces of coarse

woody debris.

Understory Vegetation 

This vegetation supplies food, shelter, and cover for

about 100 species of wildlife including all game species.

This vegetative component includes not only the herbaceous layer but deciduous shrubs and trees. Those that 

produce hard or soft mast (nuts and certain fruits) are of

particular concern due to the large number of wildlife

species (including nectaring species) that depend on this

relatively small number of tree and shrub species for their

well-being. These practices include:

• identification and retention of mast-producing trees 

and shrubs,

• planting appropriate trees and shrubs,

• thinning overstory trees to assure suitable space and 

sunlight is available for these species.

Forage Seeding

Several wildlife forage seed mixes are available that

can readily be applied to disturbed areas such as skid roads,

logging roads, landings, slash burn sites, or other disturbed
sites. Appropriately applied in the spring and/or fall, these

mixes often result in increased wildlife forage for birds 

and mammals, nest site availability, reduced erosion, and

reduced invasion and establishment of non-native invasive

weed species on those sites.

Variable Density Thinning

There are many different approaches to adding both

vertical and horizontal diversity within even-aged stands

with variable density thinning, a very workable system

when thinning (both precommercial and commercial)

stands. This involves creating openings in closed canopy

stands that are at least one site-standard tree height in

diameter and leaving clumps of the same general size that

are lightly thinned or unthinned to accommodate those

species needing hiding, nesting, or escape cover in closed

canopy stands. Residual trees can be left in openings if the

canopy closure is less than 40 percent after thinning.

Shrubs may be retained in openings or planted along with 

a forage seed mix to accommodate understory and shrubdependent wildlife. Snags of all heights including high

stumps may be created or retained in these openings.

Hazard trees may be centered in unthinned or lightly thinned patches so safety is not compromised while retaining

wildlife structure. In even-aged stands, these variations to

the standard prescribed thinning regime should total at least

one-fourth of the stand. Stands proposed for a variable

thinning regime should be evaluated on the basis of surrounding stand structure and stand size. 

Hydrological Restoration

Very well-developed and stringent legal requirements

are in place for identified riparian zones and forested wetlands. However, opportunity exists to protect very important aquatic and adjacent terrestrial habitats through seep

and spring development, identification and protection of

headwall environments, and alternate plans developed

through the SFLO of the DNR. Most of the techniques

have been developed to protect aquatic species with an

emphasis on salmonids. However wildlife habitat, for both

terrestrial and aquatic species, can be created by restoring

or creating small spring and seep pools where they have

been disturbed from previous forest activities. 

Other techniques are available that are wildlife-species

and site specific and are tailored for those individual situations and landowners desiring to create special habitats.

These may include watering devices, tree inoculation to

produce habitat for cavity-nesting species in live trees, nest

boxes and platforms, and special plantings, among other

activities. 

TECHNICAL/FINANCIAL ASSISTANCE

Several sources of technical or financial assistance are

available through the DNR and other agencies. These

include:

Forest Stewardship Program (FSP) - contact at:

www.forest_stewardship@wadnr.gov , (360) 902-1706, 

or a regional Stewardship Forester. FSP includes technical

assistance in general forest management, wildlife, forest

health, fire hazard reduction, forest stewardship management plans, and educational programs including Coached

Stewardship Planning classes in conjunction with WSU

Extension Forestry. The FSP also oversees cost-share 

practices for the above areas through the Forestland

Enhancement Program.

Small Forestland Owners Office (SFLO) - contact at:

www.dnr.wa.gov/sflo, (360) 902-1391 or regional SFLO

foresters. SFLO programs include technical assistance for

Forests and Fish issues. Cost-share programs include

Forestry Riparian Easement Program, Riparian OpenSpace, and the Family Forest Fish Passage Program.

The Natural Resources Conservation Service of the

U.S. Department of Agriculture administers cost-share 

programs that may benefit small forestland owners. These

include: Environmental Quality Incentives Program,

Wildlife Habitat Incentives Program, and the Conservation

Reserve Enhancement Program. 

The Washington Department of Fish and Wildlife

administers the Landowner Incentives Program for specific

wildlife species or habitats.

The U.S. Fish and Wildlife Service of the Department

of Interior also administers several cost-share programs for

selected species or geographic areas that may be of benefit

to some forestland owners.

SUMMARY

Family forests are different in distribution, size, 

and content from managed public and industrial forests.

Furthermore, family forest owners often have very different

objectives and concerns for their forests when compared to

those managed primarily for timber resources. Protecting

or enhancing wildlife habitat is often a primary objective

for these NIPF lands. Many techniques are available that

protect, enhance, and even create several important habitat

features that accommodate the majority of wildlife

63
resources found in these smaller privately owned low-elevation stands. These techniques can be implemented in the

course of standard forest management activities including

pre-commercial and commercial thinning and final overstory removal in Westside forests. The challenge to foresters is to not only include these techniques in their standard

silvicultural prescriptions but consider an ecosystem

approach in the future. While landowners are constrained

to applying these wildlife habitat management techniques

to their land, the majority not only recognize the value of

landscape and ecosystem management, but also are highly

interested in joining with other family-owned forest owners

in applying ecosystem management principles (Creighton

et al. 2005).

LITERATURE CITED

Baumgartner, D.L.; Creighton, J.H.; Blatner, K.A. 

2003. Use and effectiveness of Washington State’s

extension Forest Stewardship Program. Small-scale

Forest Economics, Management and Policy. 2(1): 1-13.

Creighton, J.H.; Baumgartner, D.M.; Blatner, K.A. 

2002. Ecosystem management and non-industrial 

private forest landowners in Washington State, USA.

Small-scale Forest Economics, Management and

Policy. 1(1): 55-69.

Creighton, J.H. 2005. Personal communication. 

Department of Natural Resource Sciences. Pullman,

WA: Washington State University. 

Gootee, R.J. 2004. Family forests: challenges of investment and stewardship. In: Baumgartner, D.M.; ed.

Proceedings of human dimensions of family, farm, and

community forestry international symposium. Pullman,

WA: Washington State University: 13-16.

Johnson, A. 1997. The importance and differences in 

non-industrial forest landowners. Western Forester.

42(7): 1-4.

Mannan, R.; Meslow, E.C.; Wight, H. 1984. Use of 

snags by birds in Douglas-fir forests, western Oregon.

Journal of Wildlife Management. 44: 787-797.

Neitro, W.; Mannan, R.; Taylor, D. [et al.]. 1985. Snags. 

In: Brown. E., tech. ed. Management of wildlife and

fish habitats in forests of western Oregon and

Washington. Part 1, Chapter narratives. R6-F&WL192-1985. Portland, OR: U.S. Department of

Agriculture, Forest Service, Pacific Northwest Region:

129-169.

Perkey, A. 1989. Assessing wildlife habitat management 

objectives on the private non-industrial forest. National

Woodlands. January-February 1989: 6-8.

U.S. Department of Agriculture [USDA]. 2000.

Summary Report: 1997 National Resources Inventory

(revised December 2000). Natural Resources

Conservation Service, Washington, DC, and Statistical

Laboratory, Iowa State University, Ames, Iowa. 89 p.

http://www.nrcs.usda.gov/TECHNICAL/NRI/1997/

summary_report/. (Date accessed unknown).

Urban, D.; O’Neil, R.; Shugart, H., Jr. 1987. Landscape 

ecology—a hierarchical perspective can help scientists

understand spatial patterns. Bioscience. 37: 119-127.

Washington State Department of Natural Resources 

[WDNR]. 1999. Forest statistics. Olympia, WA: 

Forest Stewardship Program. 

Washington State Department of Natural Resources 

[WDNR]. 2002. Forest statistics, Small Forest

Landowners Office. 1 p.

Zarnowitz, J.E.; Manuwal, D.A. 1985. The effects of 

forest management on cavity nesting birds in northwestern Washington. Journal of Wildlife Management.

49(1): 255-263.

64
ECONOMIC

CONSIDERATIONS
This page is intentionally left blank.
1 Angus Brodie is Manager with Washington State Department of Natural Resources, 1111 Washington St SE, Olympia, WA 98504, USA 2 Michael Bowering is Forester with D.R. Systems Northwest Inc. Nanaimo, BC, Canada 3 Weikko Jaross is Forest Management Analyst with Washington State Department of Natural Resources, 1111 Washington St SE, Olympia, 

WA 98504, USA 4 Don Reimer is President of D.R. Systems Northwest Inc. Nanaimo, BC, Canada 5 Bryan Lu is Forest Management Analyst with Washington State Department of Natural Resources, 1111 Washington St SE, Olympia, WA 98504, USA

Managing for Wildlife Haitat in Westside Production Forests

COMBINING MANAGEMENT GOALS OF

WILDLIFE HABITAT CONSERVATION AND REVENUE 

ON WASHINGTON STATE TRUSTS

Angus Brodie1, Michael Bowering2, Weikko Jaross3, Don Reimer4, and Bryan Lu5

INTRODUCTION

People in Oregon and Washington are interested in 

conserving wildlife (Carey, 2003), biodiversity and local

economies, while obtaining other useful services from the

forests. Forestry professionals are struggling to keep up

with changing societal demands (Kimmins 2002). A major

challenge for forest managers in recent decades has been

habitat conservation for threatened and endangered species.

One of the more visible species of concern has been the

northern spotted owl (Strix occidentalis caurina). The

northern spotted owl rests on top of a complex food 

web in natural old forest habitats in western Oregon and

Washington (Carey 2003). Because of its position in the

food web, the northern spotted owl represents a keystone

complex, and serves as a focal point for understanding the

ecological processes and structural functionality of older

ABSTRACT

In 1997, the Washington State Department of Natural Resources (WDNR) adopted a multiple species Habitat

Conservation Plan (HCP) with the United States Fish and Wildlife Service (USFWS) and the National Oceanic and

Atmospheric Administration – Fisheries (NOAA Fisheries) for 1.6 million acres of State Trust forestland. Between 2001

and 2004, WDNR analyzed a number of management alternatives in western Washington. A fundamental management 

challenge of the HCP is the integration of wildlife habitat enhancement and revenue generation. This paper describes the

forest modeling and silvicultural analysis, conducted as part of the sustainable harvest calculation, with a focus on management strategies to create high quality nesting habitat for the northern spotted owl in accordance with the goals of the HCP.

Results are reported for both stand- and landscape-level analysis in terms of selected environmental and economic performance metrics. Discussion on the application and implementation of these regimes at the tactical and operational levels are

included. 

KEYWORDS: Silviculture, Douglas-fir, western hemlock, northern spotted owl habitat, forest management.

67

large diameter conifer forests. Ecological processes in the

forest are a product of dynamic forest development through

time (Franklin et al. 2002). It is through investigation of

forest development that management approaches will be

found to improve habitats for the owls and other species

associated with old forests. 

In 1997, the Washington State Department of Natural

Resources (WDNR) adopted a multiple species Habitat

Conservation Plan (HCP) with the United States Fish and

Wildlife Service (USFWS) and the National Oceanic and

Atmospheric Administration– Fisheries (NOAA Fisheries)

for 1.6 million acres of State Trust forestland. While the

HCP was developed to provide habitat conservation for

multiple wildlife species, one of the main species of concern was the northern spotted owl. The stated conservation

objective for the northern spotted owl “... is to provide
habitat that makes a significant contribution to demographic support, maintenance of species distribution, and facilitation of dispersal” (WDNR 1997).

Development of a managed forest is determined by the

objectives of the landowner and achieved through the practice of silviculture. Nyland (1996) defines silviculture as

“...the theory and practice of controlling the establishment,

composition, character and growth of forest stands to satisfy specific objectives.” Research projects have been

implemented in recent years to investigate alternative silvicultural approaches designed to integrate achievement of

habitat enhancement with revenue generation in Pacific

Northwest forests (Curtis et al. 2004, Peterson and Maguire

2005). Computer-generated stand- and landscape-level simulations provide an additional method by which to examine

alternative management approaches (McCarter 2001). In

this paper, we present WDNR simulation and analysis of

stand- and landscape level silvicultural regimes for the

management of wildlife habitat and revenue on State Trusts

forestlands in western Washington.

The purpose of our analysis was to examine management alternatives identifying economically effective

regimes that could create forest structures suitable for

northern spotted owl nesting habitat. We chose two performance criteria to test the performance of potential regimes.

For economic comparisons, a net present value (NPV) was

calculated based upon simulated management costs and

revenues. For habitat comparisons, the time to reach the

desired future condition (as defined by nesting habitat forest structure attributes) was estimated from treatment and

growth projections.

METHODS

Habitat Threshold Targets

Unlike traditional commercial thinning regimes that

focus on creating forest stands to maximize timber values

(i.e. harvest revenue, clear wood, recovery of mortality,

increased growth rates), our regime analysis focused primarily on creating forest structures to satisfy the Habitat

Conservation Plan habitat definition. The design of our 

silviculture regimes incorporated biodiversity pathway 

concepts adopted from Carey et al. (1996), Lippke et al.

(1996) and Bare et al. (1997). In particular, we examined

the influence of initial stand density, pre-commercial thinning and commercial thinning treatments on habitat development during the first 100 years after forest establishment.

Treatment regimes were designed to produce stand attributes associated with high quality owl habitat as identified

by the WDNR HCP (WDNR 1997). The high quality owl

habitat threshold targets are presented in table 1. 

Problems in the definition and measurement of canopy

closure or canopy cover (Jennings et al. 1999) convinced

us that attempts to use canopy parameters for assessing

habitat thresholds were unworkable. We therefore did not

address this criterion in our tests. Canopy closure plays an

important role in the life history requirements of the northern spotted owl, providing cover from predators and thermal regulation (Hanson et al. 1993). Instead, we assumed

the combination of overstory trees of the required diameters and the development of understory shrubs and trees

occurring 30 to 40 years after thinning would adequately

fulfill the life history requirements of the spotted owl and

its associated prey. 

The HCP requires a relatively high proportion of large

snags relative to what occurs in the modeling output of a

younger managed stand, therefore we assumed that if snags

are absent within the stand, they will need to be created

from live trees. This notion of snag recruitment was discussed in Carey et al. (1996), and the cost for creating

these snags was deemed negligible (Lippke et al. 1996). To

achieve the required proportion of live and dead trees per

acre and maintain sufficient recruitment for large down

woody debris, we identified a minimum residual stand density for the final thinning to be 45 trees per acre. Retention

of at least 45 trees per acre provided a margin of 14 trees

of the requisite diameters with which to recruit additional

potential snags and down woody debris as a result postharvest.

Operational Considerations

Dense stands with small live crowns may be exposed to

abiotic loss (i.e. snowpress, breakage, windthrow) after

thinning if the height/diameter ratio is greater than 100

(Daniel et al. 1979). Although this varies somewhat among

species, if the live crown ratios of thinned stands are small,

it is likely that trees will show little growth response. To

minimize the effects of these factors, two additional decision rules were incorporated into the analysis:

1) The height/diameter ratios of the residual stand 

must be less than 100. 

2) The live crown ratio must be greater than 45 

percent.

In addition, a minimum thinning harvest of 8,000 board

foot per acre was used as a test to rank the feasibility of the

regimes. This thinning harvest level represents the average

thinning sale yield from WDNR over the last 5 years

(2000-2005).

68
Treatment combinations producing stands that failed to

meet the HCP stand attribute requirements, with the exception of canopy closure; resulted in a residual stand having a

height/diameter ratio greater than 100 or a live crown ratio

less than 45 percent; or had a thinning harvest less than

8,000 board feet per acre at some point in the yield projection were rejected from further analysis.

Financial data

Our investigation was to identify management regimes

that could reach the target conditions in an economically

efficient manner therefore, all treatment combinations were

modeled using a set of treatment costs, planting scenarios,

merchantability limits and interest rate assumptions as

shown in table 2. Log prices were developed from 2002-03

data with consultation from WDNR marketing staff

(Bowering and Reimer 2003).

Silvicultural regime analysis was conducted using 

D.R. Systems’ proprietary silvicultural analysis model,

SILVIRR. The model, SILVIRR, uses the Stand Projection

System (SPS version 4.1H, as supplied by Mason Bruce

and Girard) to project stand attributes. The model, SPS, is a

growth and yield model that simulates the development of

individual trees and reports by diameter class. While other

growth and yield models were considered for this analysis,

we chose SPS because it was integrated with the forest

estate or harvest scheduling model that WDNR used to

model the sustainable forest management recommendations

for the Board of Natural Resources in 2004 (WDNR 2004).

The analysis conducted on representative single species

Douglas-fir (Pseudotsuga menzieii) and western hemlock

(Tsuga heterophylla) stands, across five site classes. The

species-specific site index values presented in table 3 were

species converted by SPS to an equivalent Douglas-fir site

index. SPS uses a ratio of 0.9 times the Douglas-fir site

index for western hemlock to produce the Douglas-fir

equivalent. The height growth is, however, based upon the

appropriate height growth curves (King 1966, Wiley 1978).

Due to the number of treatment combinations, only the representative site indices presented in table 1 were analyzed.

Regimes

A series of regimes were developed to meet the threshold target conditions of high quality nesting habitat. Regimes

were designed to incorporate a spectrum of initial planting

densities, pre-commercial (PCT) treatments, fertilization

following the PCT age (for Douglas-fir stands only), and 

a series of commercial thinning combinations using single,

double or triple entries prior to the final harvest. For the

single, double and triple pass treatments, a range of treatment timing intervals and treatment intensities were tested.

All regimes were assumed to be planted with 2 yearold seedlings and were modeled to reflect a range of initial

planting densities between 200-700 trees per acre in intervals of 50. Where the regime included a PCT treatment, 

the earliest PCT age was selected to minimize damage to

the residual stand due to an excessive height/diameter ratio.

Earliest PCT age selected was between 7 and 22 years after

establishment; dependent upon species and site quality.

Where a PCT treatment was simulated, stand densities were

reduced to 300 trees per acre (12-by-12 ft spacing). This is

consistent with PCT density targets discussed in Carey et

al. (1996) and (Lippke et al. 1996). For stand conditions

69

Table 1—Threshold target conditions used for ranking the treatment combinations (regimes)

Modeled and used

Criteria Description to screen regimes

Biological At least 31 trees per acre greater than or equal to 21 inches dbh, with at least X

high quality 15 trees per acre greater than or equal to 31 inches dbh 

nesting owl At least 12 snags per acre larger than 21 inches dbh X

habitat Minimum 70 percent canopy closure 

descriptiona Minimum 5 percent ground cover of LWD. Xb

Operational The height/diameter ratios of the residual stand must be less than 100 X

The live crown ratio must be greater than 45 percent. X

Minimum thinning harvest of at least 8,000 board feet per acre X

Economic The earliest time at which they will meet the forest structural targets X

The maximum NPV returns to the department at the time of the final X

commercial thinning

a WDNR (1997). Final Habitat Conservation Plan, Washington State Department of Natural Resources, Olympia, Washington. b This was indirectly modeled. An assumption was made that required the retention of more live trees per acre at the final commercial thinning

treatment to supply logs for down woody debris
with an initial planting density of 300 trees per acre or less,

no PCT was simulated. We also simulated a fertilizer treatment for the Douglas-fir stands. The fertilizer treatment

was applied 1 year after the PCT treatment or at an equivalent age for low initial density stands.

Thinning Treatment Combinations

A set of thinning treatment combinations were designed

to explore alternative approaches to accelerating achievement of forest structure threshold targets. The thinning

treatments varied with the frequency of entries, the time

70

Table 2—Assumptions about treatment costs, interest rates, 

stand establishment and merchantability limits used for

modeling the management regimes

Management Regime Characteristic Assumption

Treatment Cost

Regeneration Harvest Treatment Cost $180/MBF

CT Treatment Cost $280/MBF

Selection Cut Treatment Cost $280/MBF

Regeneration Cost $0.5/seedling

Brushing Cost $160/ac

Pre Commercial Thin Cost $160/ac

Interest Rates

Wood Appreciation Rate 0.3%

Inflation Rate 2%

Discount Rate 7.5%

Stand Establishment

Regeneration Method Planted (100%)

Regeneration Delay 2 yrs

Seedling Stock Type 1+1

Merchantability

Minimum Top DIB as % DBH 15%

Stump Height 1.2 feet

Minimum DBH 6 inches

Minimum Top DIB 4 inches

Nominal Log Length 32.5 feet

Minimum Log Length 12.5 feet

Average Defect 2%

Pre Commercial Thin d/D ratio 1.0

Commercial Thin d/D ratio 0.9

Fertilization

Application Rate (DF species only) 200 lbs N/ac

Cost $90

Table 3—Site index classes and the representative site index for each species

Site Class Douglas-fir Site Index Western hemlock Site Index

Site I 143 159

Site II 127 141

Site III 109 121

Site IV 89 99

Site V 68 77
that a stand might be entered, and the amount of residual

trees that would be left after the thinning (table 4). The

combinations of multiple planting densities, PCT, fertilization, and commercial thinning options, applied across the

five site classes, resulted in 45,900 regimes for Douglas-fir

stands and 30,600 regimes for western hemlock (table 5).

The total number of regimes simulated in SILVIRR was

76,500. 

All stands were simulated for 150 years of age. Net

Present Value (NPV) was evaluated at the final commercial

thinning, not at regeneration harvest. 

Post Simulation Analysis

A compilation algorithm was developed to select suitable treatment combinations that met the set of biological,

operational and economic threshold targets (table 2).

Treatment combinations for Douglas-fir and western 

hemlock by site class were initially screened using the 

following priorities: 1) the residual stand meets the stand

structural objectives for high quality nesting habitat at

some point in the 150 year projection; 2) the residual stand

and thinning treatment met the operational tests. Once the

screening was complete, the regimes were ranked according to the two evaluation criteria: maximum Net Present

Value (NPV) and the least time to reach the desired future

habitat condition. 

Once the regime screening was complete, silvicultural

considerations, such as thinning timing, intensity and residual target densities of the highest ranking treatment scenarios were used as input variables for a landscape simulation

model that was developed for the analysis of alternatives

for sustainable forest management of State Trust lands in

western Washington (WDNR 2004). Forest stands were

assigned regimes in the landscape simulator based on the

land classification and existing stand conditions. Regimes

that create forest structures suitable as high quality nesting

habitat for northern spotted owls were labeled “biodiversity

pathways” after Carey et al. (1996). Both short and long71

Table 4—Matrix of treatment components for the treatment scenarios

Thinning treatment entries

Pre-commerical Single entry Two entries Three entries

Planting thinning and Residual trees Residual trees Residual trees

densities fertilization Age per acre Age per acre Age per acre

First entry First entry

200 Douglas-fir 30 45 30 75 30 150

250 No PCT 35 55 35 100 35 175

300 PCT to 300TPA 40 65 40 125 40

350 PCT to 300TPA

Fertilization 45 150

400 50 175

450 Western hemlock 55

500 No PCT 60

Second entry Second entry

550 PCT to 300TPA 50 45 50 75

600 60 55 60 100

650 70 125

700

750

Third entry

70 45

80 55

a All regimes were assumed planted with 1/1 stock 

b PCT treatments were not applied to stands below 300 tpa at the time of the PCT treatment 

c Fertilization of 200 lbs of N per acre, at a cost of $90/acre
rotation biodiversity pathways were developed for areas of

these State forest lands; identified as important for northern

spotted owl conservation, riparian habitat enhancement,

protection of unstable slopes, or maintenance of forested

visual areas. 

We developed two additional rules to allocate the shortand long-rotation biodiversity pathways to current stands in

the landscape simulator. The first rule was that biodiversity

regimes were only applied to conifer dominated stands.

The second rule was designed to minimize the risks of

stand failure (wind-throw) due to heavy thinning (Somerville

1980, Wilson and Oliver 2000, Cameron 2002). Longrotation biodiversity pathway regimes were assigned only

to stands with an inventory basal area per acre less than 

the projected average yield curve for their forest type and

site class. Short rotation biodiversity pathway regimes 

were assigned to stands with inventory basal areas per acre

greater than the estimated basal areas per acre from the

projected average yield curve for their forest type and site

class. 

RESULTS

A total of 24,294 regimes produced high quality nesting

habitat for owls (table 6). The conditionally passed label

indicated that a stand had met all the criteria with the

exception of meeting the 31-inch diameter-at-breast-height

(DBH) limit for the 15 largest trees per acre. The HCP

indicates that if this required number of large trees per acre

is not present then the next largest should be maintained to

provide a total of 31 trees per acre larger than 21 inches

DBH (WDNR 1997). 

The regimes that ranked highest in terms of maximum

NPV are presented in table 7. On medium to high sites 

(site class III and higher), the highest ranking regimes had

moderate levels of initial stocking (planting densities of

between 300 and 650 trees per acre), did not receive PCT

(except on DF site class III) and incorporated two commercial thinnings. The first commercial thinning occurred

between 30 and 40 years of age with a residual density of

125 and 175 trees per acre. The second thinning occurred

10 to 20 years later depending on the site with a residual

density of 45 trees per acre. The NPV at this last commercial thinning was $257 per acre (site class III western 

72

Table 5—Number of regimes for each species and site class

Treatment combinations Douglas-fir Western hemlock Total

No PCT + Single Pass CT 252 252 504

No PCT + Double Pass CT 1,080 1,080 2,160

No PCT + Triple Pass CT 1,728 1,728 3,456

PCT + Single Pass CT 252 252 504

PCT + Double Pass CT 1,080 1,080 2,160

PCT + Triple Pass CT 1,728 1,728 3,456

PCT + Fertilization + Single Pass CT 252 — 252

PCT + Fertilization + Double Pass CT 1,080 — 1,080

PCT + Fertilization + Triple Pass CT 1,728 — 1,728

Total Combinations by Site Class 9,180 6,120 15,300

Total Run Combinations for all Five Site Classes: 45,900 30,600 76,500

Table 6—Number of the regimes that passed, conditionally passed 

and failed to meet HCP high quality habitat stands during the 

150 year projection

Douglas-fir Western hemlock Total

Pass 10,448 9,703 20,151

Conditional pass 1,825 2,318 4,143

Fail 30,333 16,559 46,892

Total 42,606 28,580 71,186
hemlock) and $1,423 per acre (site class I Douglas-fir).

Stands on medium sites achieved the desired structural

condition between stand age 90 and 150 years. Dependent

upon site, fertilization of the stand could reduce the stand

age at which the structural condition was attained by 10 to

30 years (table 7).

Ranking the regimes provided results in terms of which

regime performed the best under economic and time criteria. To illustrate the amount and the source of the variation

produced by the regime analysis, we chose to examine indepth the economic performance of regimes for one species

and site class: Douglas-fir site class III. 

Figure 1 illustrates the variation in NPV and the stand

age when habitat criteria are attained for Douglas-fir site

class III regimes. The results indicate that a higher NPV

at the final commercial thinning results in a delay in the

attainment of habitat. Regimes with the highest NPV

attained habitat at a stand age of 140 years. The regimes

that return the highest NPV at 140 years tend to be regimes

with only thinning treatments in them rather than regimes

with thinning and a combination of PCT and fertilization

(fig. 2). The influence of initial stocking on NPV for thinning only regimes that attained habitat at 140 years is presented in figure 3. The results illustrate a trend: moderate

(400-599 trees per acre) to high (600-750 trees per acre)

densities with multiple thinning entries result in the highest

NPV. 

On lower sites (site class IV and poorer), the silvicultural regimes were characterized by lower initial stocking

(except site class IV Douglas-fir) with planting densities 

of 200-300 trees per acre, no pre-commercial thinning and

only one thinning entry at between 40 and 55 years of age

designed to leave a residual density of 45 trees per acre.

The NPV at last commercial thinning ranged from $-125

(site class V Douglas-fir) to $98 per acre (site class V

Douglas-fir with fertilization). Fertilization on very poor

sites (site class V) improved the economic performance of

the NPV from a negative value to above zero. Stands on

lower sites took between 140 and 150 years to reach the

desired structural condition and fertilization did not appear

to speed the development of the stand.

73

Table 7—Regimes that provided the highest NPV at the final commercial thinning

Re- Re- NPV

Initial First sidual Second sidual at final Forest Attainment

Site Regime stock- thin- stock- thin- stock- thin- structure of forest 

Species class description ing ning ing ning ing ning status structure

(tpa) (yrs) (tpa) (yrs) (tpa) ($/ac) (yrs)

DF I Two thinnings 500 30 174 50 45 1,424 Pass 90

DF I Fertilization and 300 35 149 50 45 1,202 Pass 80

two thinnings

DF II Two thinnings 600 30 149 50 45 975 Pass 100

DF II Fertilization and 300 35 149 50 45 944 Pass 90

two thinnings

WH I Two thinnings 550 40 124 50 45 837 Pass 100

WH II Two thinnings 500 40 174 50 45 540 Pass 110

DF III Two thinnings 650 40 124 50 45 460 Pass 150

DF III Fertilization and 300 40 99 60 45 351 Pass 120

two thinnings

WH III Two thinnings 350 40 174 50 45 257 Pass 120

DF IV Fertilization and 300 40 44 96 Pass 150

one thinning

DF V One thinning 250 55 44 3 Condition 150

WH IV One thinning 200 55 44 (2) Pass 150

DF V Fertilization and 300 50 44 (4) Condition 150

one thinning

WH V One thinning 200 60 44 (56) Condition 140

DF IV PCT and one 600 45 44 (125) Pass 150

thinning
The most successful strategy found to maximize NPV

while accelerating development of the target forest structural conditions employed a moderate first commercial

thinning at age 30 to 40 years of age (~ 150 trees per acre,

Curtis’ relative density (RD) target of 35-45) followed by 

a second thinning 10 to 20 years later to a residual stand

density target of RD 20-25 and approximately 45-50 trees

per acre.

The management regimes that ranked highest in accelerating development of the desired structural conditions are

presented in table 8. The most successful strategy for attaining the forest structural conditions at the earliest age on site

class III for Douglas-fir and western hemlock had a stand

establishment density of 350 tree per acre, PCT to 350

trees per acre combined with fertilization and one commercial thinning at age 30. Attainment of the forest structural

threshold on site class III stands would occur at a stand age

of approximately 80 years. For higher sites, site class I and

II, the strategy is similar except that initial stand establishment density levels are lower (200-250 trees per acre),

there is no pre-commercial thinning treatment applied and

structural targets are reached as soon as 60 years.

Analysis results indicate that two or more commercial

thinning treatments may delay the attainment of the forest

structural targets by as much as 40-50 years. For example,

in site class III lands, desired stand structural conditions

are delayed from 80 to 120 years. Two commercial thinning entries on Douglas-fir site class III increase the NPV

per acre by $250. This $250 per acre can be considered as

the present value of the opportunity cost of faster attainment of desired forest structure.

The forest treatments found to maximize NPV and 

the treatments producing the earliest attainment of desired

structural conditions were input into a landscape model.

Two regimes were developed, a long-rotation “biodiversity

pathway” and a short-rotation “biodiversity pathway”

(WDNR 2004). The long-rotation “biodiversity pathway”

favored the silvicultural characteristics of the scenarios that

maximized NPV, while the short-rotation “biodiversity pathway” followed more closely the silvicultural approaches of

the treatment combinations that accelerated development 

of desired structural conditions at the earliest age.

In the landscape simulation all stands are assigned to 

a regime at the beginning of the simulation. Twenty-seven

percent of the State Trust forestland in western Washington

74

Figure 1—Douglas-fir site class III all regimes (mean (dashed line) median, 10th, 25th, 75th, and 90th percentile)
75

Figure 2—Regimes for Douglas-fir

site class III that attained the habitat

criteria at 140 years of age (mean

(dashed line) median, 10th, 25th, 75th

and 90th percentile).

Figure 3—Initial stocking effect on

regimes with thinning treatment only

(no PCT or fertilization) for Douglasfir site class III that attained the habitat criteria at 140 years of age (mean

(dashed line) median, 10th, 25th, 7th

and 90th percentile).
was assigned a long-rotation biodiversity pathway regime,

and 43 percent was assigned a short-rotation biodiversity

pathway regime. The remaining 30 percent of the forest was

assigned to regimes that maximized NPV while retaining

large, structurally unique trees, snags and down woody

debris.

In addition to these regime allocations, the simulation

model has stand- and landscape-level rules that represent

the WDNR’s policy objectives and operational constraints.

The modeling rules will modify or prevent some treatments

from occurring. For example, WDNR’s HCP contains a

landscape management strategy to maintain 50 percent of a

watershed in a suitable northern spotted owl habitat condition in designated areas. Stands in these watersheds that are

selected by the model to contribute to the target must maintain a specific relative density (RD) at all times. A thinning

treatment may be available in the simulation run for these

stands; however the landscape rule will prevent the thinning action from lowering the relative density below the

specified landscape-level rule. 

Compared with the performance of a conventional thinning alternative6 from the 2004 analysis (WDNR 2004),

the biodiversity pathways thinning approach resulted in a

lower NPV over the 64-year planning horizon. The biodiversity pathway alternative produced an NPV of $3.0 billion while a more conventional thinning approach resulted

in an NPV of $3.3 billion. However, the biodiversity 

pathway alternative produced nearly twice as much “high

76

Table 8—Regimes that provided the earliest age of meeting the HCP high quality habitat objectives by species and 

site class

Re- Re- NPV

Initial First sidual Second sidual at final Forest Attainment

Site Regime stock- thin- stock- thin- stock- thin- structure of forest 

Species class description ing ning ing ning ing ning status structure

(tpa) (yrs) (tpa) (yrs) (tpa) ($/ac) (yrs)

DFa I Fertilization and 250 35 44 903 Pass 60

one thinning

DF I One thinning 350 30 44 739 Pass 60

WHb I One thinning 250 30 44 341 Pass 60

DF II One thinning 45 30 44 626 Pass 70

WH II One thinning 250 30 44 136 Pass 70

DF III Fertilization, 350 30 44 102 Pass 80

PCTc and 

one thinning

WH III One thinning 250 30 44 -0.4 Pass 80

DF III One thinning 350 30 44 194 Pass 90

DF V Fertilization, 350 55 64 -97 Condition 130

PCT and one 

thinning

DF V One thinning 400 60 64 -112 Condition 130

WH IV One thinning 350 35 44 -62 Pass 130

DF IV Fertilization 250 40 44 66.6 Pass 140

and one 

thinning

WH V One thinning 200 60 44 -56 Condition 140

DF V PCT and one 600 45 44 -125 Pass 150

thinning

a Douglas-fir

b Western hemlock c PCT = pre-commercial thinning

6 In this conventional thinning alternative, commercial thinning treatments are limited to 30-35 percent removal of basal area per acre per entry. 

This intensity of thinning is representative of commercial thinning practices in the Pacific Northwest (Curtis et al. 1998). 
quality” forest structure (137,000 acres) as compared to the

conventional thinning alternative (30,000 acres) (fig. 4,

table 9). 

DISCUSSION

Managing for wildlife habitat and revenue is an explicit

policy objective of WDNR (WDNR 2006). The WDNR

adopted a HCP in the mid-nineties (WDNR 1997) and

developed landscape level strategies to support northern

spotted owl conservation through active habitat management. In 2004, the WDNR presented to the Board of

Natural Resources a new plan by which to achieve these

objectives and generate revenue. 

In developing the new plan, we undertook a silvicultural regime analysis to search for the most economically

efficient and effective management approaches to develop

forest structural conditions that meet the WDNR HCP high

quality spotted owl nesting habitat definition (WDNR 1997).

77

Figure 4—Landscape simulation model outputs comparing alternative silvicultural approaches

to developing high quality nesting habitat.

Table 9—Projection of 1.4 million acres of State Trust lands managed by the 

WDNR for three alternative management scenarios

Alternatives Forest structures equivalent

to high quality nesting habitat Net Present 

in 2064a Value in 2064

Acres $ billions

Convention thinning approach 30,000 $3.3

Biodiversity pathways 137,200 $3.0

a Forest stand development stages that are equivalent to high quality nesting habitat are Niche diversification 

and Full functional stages (WDNR 2004). Current conditions for 2004 are estimated at 16,100 acres.
78

Results suggest that heavy thinning treatments at an early

age combined with an extended rotation, up to 140 years,

may be the most effective. Our proposed “biodiversity

pathway” regimes represent a departure from more commercial silvicultural practices targeted toward maintaining

fully stocked stands, capturing mortality and shortening

rotations (Curtis et al. 1998, Hummel 2003). 

Our proposed regimes are similar to those developed a

decade ago by Lippke et al. (1996) and Bare et al. (1997)

for their analysis of biodiversity pathways. Latta and

Montgomery (2004) and Andrews et al. (2005) describe

developing similar regimes to achieve old forest structural

forest conditions in western Oregon. Zobrist and Hinckley

(2005) also describe similar silvicultural regimes in their

review of management practices to support increased 

biodiversity in Douglas-fir plantations.

The residual tree densities of our final thinning treatment are low, 45-60 trees per acre. A number of retrospective studies of forest development suggest that existing

old-growth stands may have developed at similar low tree

densities (Tappeiner et al. 1997, Acker et al. 1998, Poage

and Tappeiner 2004). Other studies, such as Winter et al.

(2002) and Zenner (2005), have suggested that old-growth

forest structures can develop with higher initial densities

after extended periods of growth and differentiation. Our

simulation results suggest that a low-tree-density development pathway may be viable to use in young plantations

and could lead to the development of large overstory 

diameter trees. 

Our analyses concentrated on the development of the

overstory trees and lead us to deficiencies in simulating

important owl habitat criteria, such as canopy closure.

Regeneration of a new cohort post thinning is a typical

phenomena in Douglas-fir and western hemlock stands

(DeBell et al. 1997, Bailey and Tappeiner 1998). Other

studies, such as Andrews et al. (2005), provided an analysis using ORGANON of understory development post

thinning. Heavy thinnings implemented in low quality owl

habitat (sub-mature and young forest marginal) will lead to

a reduction of canopy closure, and therefore, a loss habitat

until canopy closure is restored. Being able to demonstrate

the recovery of canopy closure is a deficiency in our simulations and requires further study. 

The spatial arrangement of the residual trees after the

thinning entries should be an important consideration in

planning for the growth of the overstory and understory.

Unfortunately, spatially explicit modeling of stem distributions is problematic and was not attempted as part of this

investigation. Unlike traditional, uniform thinning; the

thinning treatments associated with these biodiversity

pathway regimes will likely be irregular, with differing

densities, unthinned patches, and small openings across 

the stand (Curtis et al. 1998). Such an approach to thinning

treatment has been described as “variable density thinning” (Carey and Curtis 1996, Carey et al. 1999). 

The final thinning entry, simulated in this analysis,

retained a relatively low average residual tree density of

approximately 45 trees per acre. This treatment can be

considered as a partial harvest (WDNR 2004) or as a variable retention harvest, similar to those described by Barg

and Hanley (2001) and Franklin et al. (1997). Appropriate

naming of selected treatments with descriptive silvicultural

terms can aid in the communication of management alternatives to foresters, wildlife biologists and other interested

parties.

At the stand-level, biodiversity pathway regimes do not

produce economic returns equivalent to commercial evenaged silviculture. The management regimes developed in

this project with early heavy thinning show, however, that

economic benefits can be improved when some merchantable timber is removed early in the rotation. We suggest

that it is at the landscape- or forest-level scale that the performance of biodiversity pathways should be compared to

more traditional silvicultural approaches. Forest-level

objectives for habitat conservation, as mandated by the

HCP, preclude maximization of economic return. Under

circumstances where integrated environmental and economic forest outcomes are desired, our analysis joins that

of Carey and others (1999) suggesting that biodiversity

pathways are the most effective means for reaching the

combined goals of forest habitats and revenue generation.

ACKNOWLEDGMENTS

The authors thank Fred Martin, Gretchen Nicholas,

Tami Riepe, Larry Mason, Bruce Lippke and Tim

Harrington for their thoughts and reviews. The research

leading to this paper was supported by the Washington

State Department of Natural Resources, Olympia,

Washington.

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D.P.; St. Clair, J.B.; Tappeiner, J.C.; Walstad, J.D.

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of Agriculture, Forest Service, Pacific Northwest

Research Station. 389 p.

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structure of old-growth Douglas-fir forests in central

western Oregon, USA. Forest Ecology and

Management. 204: 329-343.

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Bailey, J.D. 1997. Density, ages and growth rates in

old-growth and young-growth forests in coastal Oregon.

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[WDNR]. 1997. Final Habitat Conservation Plan.

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Resources 223 p.

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[WDNR]. 2004. Final Environmental Impact State on

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State Trust lands in western Washington and for determining the sustainable harvest level. Olympia, WA:

Washington State Department of Natural Resources.

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[WDNR]. 2006. Final environmental impact statement

on the policy for sustainable forests. Olympia, WA:

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the Pacific Northwest. For. Pap. 17. Centralia, WA:

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management in Douglas-fir plantations. Canadian

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E.A.; DeWitt, D.Q. 2002. Initiation of an old-growth

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Rural Technology Initiative, College of Forest

Resources, University of Washington.

80
1 Bruce Lippke is Professor and Director, 2 Kevin W. Zobrist is Research Scientist, and 3 Kevin Ceder is Forest Technology Specialist, Rural Technology

Initiative, College of Forest Resources, University of Washington, Box 352100, Seattle, WA 98195-2100.

Managing for Wildlife Haitat in Westside Production Forests

ISSUES AND ALTERNATIVES ASSOCIATED 

WITH PRIVATE FOREST WILDLIFE AND 

RIPARIAN HABITAT MANAGEMENT

Bruce Lippke1, Kevin W. Zobrist2, and Kevin Ceder3

INTRODUCTION

Two decades ago, declines in old forest habitats with

consequent impacts on certain species such as the northern

spotted owl prompted interest in forest management strategies that integrate protection of habitat and other ecological

values with acceptable economic returns. In 1993, the

Washington Forest Landscape Management Project brought

together an interdisciplinary team of scientists to investigate the potential for intentionally managing stands to

accelerate development of old forest conditions as a method

that might improve wildlife habitat and avoid future endangered species listings (Carey et al. 1996, Carey et al. 1999,

Lippke et al. 1996). Old forest habitat has declined as a

consequence of commercial management, forest conversions, and disturbance events that result in continued risk

81

of habitat loss and species listings in absence of direct

attempts to provide more of these old forest conditions. A

range of prescriptive treatments called biodiversity pathways was developed to accelerate old forest functionality

while providing economic revenues. The treatments were

characterized by repeated thinnings and longer rotations

than typical commercial management, with attention to

retaining downed logs, snags, and multi-layered canopies.

Evaluations of the biodiversity pathways indicate that they

could be used to develop late seral characteristics in young,

dense, managed stands more rapidly and at less cost than

by setting the stands aside as no-harvest reserves, which

would require a long time for natural processes to result 

in the desired structural diversity associated with older

forests.

ABSTRACT

Efforts to provide habitat for species in decline invariably fall back on managing stands to emulate older forest conditions

as the forest structure in greatest decline. To more quickly achieve old forest structural conditions that were thought important

to the survival of the northern spotted owl (Strix occidentalis), biodiversity thinning pathways were designed to reinitiate

understory and more complex structures including consideration for retaining downed logs, snags and multiple canopy layers.

Stream buffer rules have since evolved to target natural old forest conditions as the desired future condition (DFC) along

streams. The economics of no-management and even longer rotations to achieve old forest structures generally falls below

acceptable rates of return providing motivation for land conversion. Alternative management approaches that allow thinning

treatments and narrow buffers cost landowners much less, reduce the motivation for land-conversions, and have been shown to

accelerate development of desired old forest conditions along streams. Thinning in upland stands improves young forest habitat

at minimal cost while placing stands on a trajectory that can ultimately produce old forest structure albeit at an unacceptable

cost for private owners. Incentives coupled with thinning harvests can be used to offset landowner losses and may help reduce

the motivation for land conversion while contributing to achievement of habitat objectives. 

KEYWORDS: Riparian buffers, forest regulations, sustainable forestry, biodiversity pathways, old forest habitat, 

private forests.
More recently, in response to declining salmon runs,

attention has shifted towards mitigating the environmental

impacts associated with commercial forest management

adjacent to streams in the Pacific Northwest. Similar to

habitat objectives for the protection of upland species, the

goal of riparian harvest regulations in Washington and

Oregon is to allow the development of riparian forest structure similar to more complex older forests, also referred to

as the desired future conditions (DFC). An especially

important component of the DFC is the development of

large conifers as a source of shade and long-term large

woody debris (LWD) recruitment to streams. In the

absence of active management it will likely take an undesirably long time for riparian areas in young, dense stands

to achieve the DFC (Carey et al. 1999, Chan et al. 2004).

This is especially true in Washington, which requires wider

buffers with significant portions where no harvesting is

allowed.

The riparian harvest regulations in both Oregon and

Washington permit landowners to deviate from the regulatory prescription and pursue alternative management plans

for stands that are unlikely to achieve DFC without active

management. The Washington regulations further suggest

that management templates be developed for riparian

stands that are overly dense, which are expected to be 

common situations given historical management practices.

Templates would provide specific guidelines to streamline

the process for developing and approving alternate plans.

The principle biodiversity pathways that were developed earlier to restore old forest conditions in upland areas

provide useful guidance for managing riparian forests for

old forest structure as well. This management approach was

noted early-on as an alternative to reduce the cost of noharvest stream buffers in the development of the Washington

State Department of Natural Resources (WDNR) Habitat

Conservation Plan (Bare et al. 1997), and it has since been

evaluated more thoroughly in an examination of sustainable harvest practices on state forests in western Washington

(WDNR 2004). In an examination of management alternatives for small private forestlands, Zobrist et al. (2004,

2005) found that landowners, through a series of thinning

harvests modeled as biodiversity pathways, could achieve

the long-term desired condition of old forest structure in

riparian zones while protecting short-term functions and

maintaining an acceptable economic return. 

A defining characteristic of the biodiversity pathways 

is that treatments must start early in young, dense stands 

so that the height-to-diameter ratio for the retained trees 

is low enough to resist wind-throw, there is enough live

crown for a vigorous treatment response, and the maximum structure benefit is achieved over time. Since dense,

closed-canopy stands offer the least habitat diversity, early

thinnings tend to support understory development with

increased habitat at a young age while also putting stands

on a trajectory to develop more older forest functionality in

the long run. Thus these pathways achieve multiple habitat

objectives over time. Concurrently, thinnings provide early

revenue opportunities to partially offset the economic costs

of longer rotations. This paper will develop the use of these

methods for managing riparian and upland forests for better

habitat while noting some of the many ecological and economic complexities that need to be understood to promote

sustainable forest policies and avoid unintended consequences. 

ASSESSING HABITAT QUALITY

A challenge with biodiversity pathways is how to 

identify the best management alternatives. Since the goal

of the treatment path is to develop a desired stand structure, a statistical assessment procedure was developed to

determine how well a given pathway produces stand structure similar to that of older forest structures (Gehringer

2006). Treatment alternatives can be simulated to see how

long it takes for a stand to develop old forest conditions

and how long that the stand retains those conditions.

Greater tree height and diameter, and lower stand density

provide most of the discriminating characteristics that

structurally describe an older forest in the Pacific

Northwest.

The assessment procedure, in combination with an 

economic assessment of treatment alternatives, can provide

a coarse filter for identifying the most successful management pathways. Management alternatives that produce old

forest structure are likely to be more sustainable if economic returns are sufficient to sustain the land in forestry with

a lower risk of conversion to other uses. Supplemental

screening of alternatives can also be applied using additional metrics of interest, such as the potential for LWD

recruitment to streams. The variability of LWD recruitment

potential is so high, even in old forests, that it does not

help in the discrimination of old forest conditions. However,

alternatives that produce the DFC and also have high LWD

recruitment potential are considered more desirable for

stream protection on the Westside.

DEVELOPING TEMPLATES 

To identify the best treatment alternatives, a range of

biodiversity pathways are defined and evaluated for the

82
percent of time they result in statistically similar structure

to old forests, provide sustainable economic returns, and

provide other specific attributes of interest such as LWD

for stream habitat or snags that provide habitat for woodpeckers and other species. Best performing alternatives can

be developed as templates, which would provide pre-established management guidelines for an appropriate range of

site parameters. Templates would minimize the time and

expense for management planning for landowners, providing both the timing information needed for treatments and

a robust ecological and economic justification for the management approach. We will present example management

alternatives and a corresponding simplified template

designed for implementation of the best management 

alternatives at a reasonable cost. 

EXAMPLE RIPARIAN MANAGEMENT

TARGETS

To develop a management template for producing old

forest conditions in riparian areas, quantitative, objective

evaluation criteria are needed. To develop a first order ecological criterion to assess pathways relative to the DFC, a

reference dataset was established using subplots from the

Pacific Resource Inventory, Monitoring, and Evaluation

(PRIME) database, which is part of the USDA Forest

Service’s Forest Inventory and Analysis (FIA) program. 

To select conditions representative of the DFC (mature,

unmanaged, riparian stands), subplots were selected that

were at least 80 years old, were within 215 ft of a stream

and did not have a history of management. 

The structural attributes of this reference dataset were

used to create a quantitative management target representing the DFC. Potential management plans could then be

assessed to determine whether they achieve the target, producing a structure that was statistically similar to the DFC

(Gehringer 2006). Three attributes provided the best discrimination in describing the structure of the reference dataset:

stand density in trees per acre (TPA), quadratic mean diameter (QMD), and average height computed using only trees

having a diameter at breast height (DBH) greater than 12

in. The distribution of values for these attributes, when

considered simultaneously, established a three-dimensional

target region. The target region was then refined by identifying a 90 percent acceptance region around the mode (the

most likely value of the data distribution) to reduce the

influence of the most extreme or outlying data points (fig.

1). An observed stand condition in which the density, QMD,

and average height fall simultaneously within the 90 percent target acceptance region would be statistically similar

to the DFC reference dataset.

The percentage of time over a 140-year assessment

period (assessed at five-year intervals) that the stand structure for a projected management option fell within the target was established as the specific ecological performance

criterion for potential management templates. This criterion

allowed the selection of template options that achieved the

DFC quickly, maintained it until a regeneration harvest,

and then quickly re-attained it in the subsequent rotation. 

In addition to an ecological criterion, an economic 

criterion is needed. Soil expectation value (SEV), or bare

land value, is the net present value of a complete forest

rotation repeated in perpetuity given a target rate of return

(Klemperer 1996). This is perhaps the most important single economic criterion, as it measures the economic performance of the initial investment and whether it provides

an acceptable rate of return to sustain the land under forest

management. Soil expectation value is also relevant for

landowners starting with mid-rotation stands, as at some

point they will reach the end of a rotation and be faced

with the decision of whether or not to continue the template for additional rotations. Soil expectation value was

computed using a five percent real cost of money.

ASSESSING TEMPLATE ALTERNATIVES

Using the biodiversity pathway model, we defined a

range of alternatives that incorporated repeated heavy thinnings over long rotations to enhance riparian forest structure while providing acceptable economic returns. These

alternatives were designed for Douglas-fir stands with midhigh site quality and each alternative was a variation of a

base 100-year rotation. This base rotation included three

commercial thinnings, the first of which was an early commercial thinning from below to 180 TPA at age 20. Early

commercial thinnings are being utilized in lieu of pre-commercial thinnings, given new markets for small diameter

wood (Talbert and Marshall 2005). Subsequent thinnings

from below to 60 TPA at age 50 and to 25 TPA at age 70

were performed. A clearcut harvest was done at age 100,

followed by replanting Douglas-fir to a typical density of

435 TPA (Talbert and Marshall 2005). In order to keep the

costs of riparian treatments low, the timing of these entries

was chosen to correspond with upland operations, which

were assumed to be done on a 50-year rotation with a commercial thinning at age 20 (table 1).

A total of 18 potential template alternatives were generated from which to select those with the best ecological

and economic performance as the basis for template development. Each alternative included a 25-ft no clearcut zone

to provide for continuous shade and bank stability. One of

83
three prescriptions was applied in this zone: no action, no

entry after thinning to 60 TPA (60-hold), or no entry after

thinning to 25 TPA (25-hold). Beyond this bank stability

zone, either 25-hold or the full 100-year rotation was applied.

There were three total buffer widths used: 50-, 80-, and

113-ft. These widths corresponded to divisions between

buffer zones for site class II under the Washington regulations. The total width of the riparian zone was 170 ft, and

was based on the site potential tree height for site class II.

The portion of the riparian zone beyond the buffer was

assumed to be managed with the upland areas (50-year

rotation). Specific prescriptions for the 18 alternatives 

are listed in table 2.

The 18 riparian management alternatives were simulated over time using the Landscape Management System

(LMS). Landscape Management System is a program that

integrates growth, treatment, and visualization models

under a single, user-friendly interface (McCarter et al. 1998).

Landscape Management System includes a number of

regional variants of publicly available single-tree growth

models. The Stand Management Cooperative (SMC) variant of the ORGANON growth model was used to simulate

the template options (Hann et al. 1997). Simulations were

begun using an initial inventory from a 20-year-old Douglasfir plantation in southwestern Washington that is representative of a dense plantation approaching its first commercial thinning (fig. 2). The plantation had 472 TPA and a

50-year site index of 120 ft. The simulation length was 140

years for all prescriptions. For prescriptions that included a

regen-eration harvest (the 100-year rotation and the 50-

year upland rotation), replanting was done to 435 TPA and

the rotation repeated as necessary.

Using LMS projections of tree lists, stand structures 

relative to the target conditions were assessed over time.

Each management segment of the riparian area (the bank

stability zone, remaining buffer, and the riparian area out84

Figure 1—The 90 percent acceptance region of the three-dimensional structure target. The grey dots represent the

central 90 percent of the DFC dataset, while the black Xs represent the most extreme ten percent of the data points

that are rejected as the outlying values. A stand whose observed attributes fell within the 90 percent acceptance 

cluster would be statistically similar to the DFC dataset.
side the buffer) was assessed independently, and a weighted average was used to obtain an assessment score. Recognizing that the portions of the riparian area closest to the

stream are more critical for key riparian functions such as

LWD recruitment, greater weight was given for closer

proximity to the stream. To calculate the weights, potential

LWD recruitment volume was simulated for the DFC

dataset using a model that estimates the expected values 

for potentially available LWD (Gehringer 2005). The average percent of the cumulative potentially available LWD

volume derived using the DFC dataset was then plotted by

85

Table 1—Timeline of riparian entries and corresponding 

upland operations for the 100-year Douglas-fir rotation 

defined for potential riparian template options based on 

the biodiversity pathway approach

Corresponding 

Year Riparian entry upland operation

20 Thin to 180 TPA Thin to 180 TPA

50 Thin to 60 TPA Clearcut and replant

70 Thin to 25 TPA Thin to 180 TPA

100 Clearcut and replant Clearcut and replant

Table 2—18 potential template alternatives. Each alternative had a 25-ft 

no clearcut bank stability zone that was thinned to 60 TPA, 25 TPA, or left 

unthinned. The remaining portion of the buffer varied in width and was 

either thinned to 25 TPA or managed on a 100-year clearcut rotation

Bank stability Remaining buffer Total buffer

Alternative zone prescription prescription width (ft)

1 No action 25-hold 113

2 No action 100-year 113

3 No action 25-hold 80

4 No action 100-year 80

5 No action 25-hold 50

6 No action 100-year 50

7 60-hold 25-hold 113

8 60-hold 100-year 113

9 60-hold 25-hold 80

10 60-hold 100-year 80

11 60-hold 25-hold 50

12 60-hold 100-year 50

13 25-hold 25-hold 113

14 25-hold 100-year 113

15 25-hold 25-hold 80

16 25-hold 100-year 80

17 25-hold 25-hold 50

18 25-hold 100-year 50

distance from the stream out to the site potential tree height

of 170 ft where 100 percent of the potential LWD volume

was included (Meleason et al. 2003) (fig. 3). The weights

used for a management segment of a given width and distance from the stream were computed as the proportion of

the cumulative potential LWD volume recruitment for the 

corresponding segment of the cumulative curve. 

To assess economic performance, SEV was computed

for each alternative using local log prices and treatment
86

Figure 2—Photo and SVS visualization of the representative inventory used to simulate potential template alternatives. The inventory is from a Douglas-fir

plantation in southwest Washington. Photograph taken by Kevin Zobrist.

Figure 3—The average percent of the cumulative potential LWD volume recruitment by distance from the stream, based

on simulations of potentially available LWD using the DFC dataset.
costs4. Soil expectation value was calculated from the

cumulative economic contribution of each management

segment of the riparian area out to the 170-ft site potential

tree height as the extremity of the riparian area. The overall

economic performance of a stand depends on the combined

performance of the riparian and upland areas. However,

identifying management alternatives that achieve viable

economic returns for the riparian area ensures that riparian

areas do not cause a loss of economic viability, even when

they comprise a high proportion of a stand. 

IDENTIFYING PREFERRED TEMPLATE

ALTERNATIVES

The percent time in target over a 140-year assessment

period, along with SEV per riparian acre, is summarized in

table 3 for the 18 potential template alternatives. The default

prescription under the Washington regulations5 and a no

riparian harvest alternative are included as reference points.

For riparian templates to be implemented, the performance

of the default regulatory option could be considered as a

threshold for acceptance since protection should be at least

as good as the default regulatory prescription.6

The no harvest alternative performed the worst relative

to both the DFC and economic criteria. Maintaining a

dense stand with no thinning delayed the achievement of

the DFC, resulting in a low time in target score. The lack

of harvest revenue resulted in a net economic cost per acre,

as the only cash flows were the annual overhead costs,

which are assumed to apply regardless of whether a harvest

occurs. This resulted in a negative SEV (-$800). The regulatory prescription only had a marginally higher time in 

target score than the no harvest alternative, as the regulatory prescription called for no harvest within 80 ft of the

stream– this is the portion of the riparian zone which provides the majority of the potential LWD volume and has a

score weight of almost 100 percent (fig. 3). The SEV for

the regulatory prescription was negative, as there was not

enough harvest revenue to achieve the five percent target

rate of return.

All 18 of the potential template alternatives performed

better than the regulatory prescription, as the biodiversity

thinnings accelerated the development of the DFC, achieving greater time in target scores. Alternatives 1-6 had the

lowest time in target scores of the 18 alternatives, as these

alternatives did not include any thinning in the first 25 ft,

which carries a scoring weight of 0.71 (fig. 3). Economic

performance was driven by the total buffer width and

whether or not a regeneration harvest was allowed in the

area outside the bank stability zone. For the alternatives

that did not have a regeneration harvest outside the bank

87

Table 3—Percent time in target over a 140-year assessment period, along with soil expectation values (SEV)

per riparian acre for the no harvest alternative, default

regulatory prescription, and 18 potential template alternatives

Time in 

Alternative target SEV/acre

Percent Dollars

Washington 

regulations 32.1 (215)

No Harvest 31.0 (800)

1 40.1 (322)

2 46.1 106

3 40.1 (45)

4 45.8 222

5 39.9 207

6 44.1 329

7 64.5 (322)

8 70.5 106

9 64.5 (45)

10 70.2 222

11 64.2 207

12 68.5 329

13 62.1 (322)

14 68.1 106

15 62.0 (45)

16 67.7 222

17 61.8 207

18 66.1 329

Note: Parentheses indicate negative values.

4 Average Puget Sound region delivered log prices for 2000 were used, as reported by Log Lines. Logging and hauling costs were based on Lippke et

al. (1996) and varied by the average DBH of the harvested trees and whether the harvest was a clear-cut or thinning operation. The early commercial 

thinning at age 20 was assumed to break even, with no net cost or revenue. Planting costs were assumed to be $0.55/seedling ($239/acre for 435 TPA).

Since this template was developed with smaller, non-industrial landowners in mind, relatively high annual overhead costs of $40/acre were used. For 

larger or industrial landowners, $17/acre were considered appropriate. All financial calculations were done before taxes.

5 Washington regulations allow several management options. It is assumed that the default option for a clear-cut harvest is “Option 2,” which requires

a minimum 80-foot no harvest area, followed by retention of 20 conifers per acre greater than 12 inches in DBH out to edge of the riparian zone at 170

feet.

6 The regulations do not specify a performance standard for riparian protection, but given that the stated intent of the regulations is to develop the DFC, 

time in target was assumed to be a reasonable criterion.
88

stability zone (25-hold instead of 100-year), no further

harvest was done after the third thinning to 25 TPA, which

was assumed to preclude subsequent rotations. As with 

the no harvest prescription, this resulted in a negative SEV

(-$800) for those segments, as the only perpetual cash

flows beyond the current rotation were the annual overhead

costs. 

A total of 12 out of the 18 potential alternatives could

be considered as viable template options, having achieved

both increased time in target values and the five percent

target rate of return (SEV > $0). Alternatives 10, 12, 16,

and 18 performed particularly well relative to both criteria.

This allowed adding an additional potentially available

LWD as a fine filter screening criterion to refine the set of

viable options down to one or two preferred alternatives.

LWD provides important in-stream functions, and long-term

sources of LWD are typically lacking in areas of intensive

management (Bilby and Bisson 1998). The potential LWD

volume was simulated for the 12 viable template alternatives using a potentially available LWD model (Gehringer

2005). The potentially available LWD volume for each

alternative is plotted in figure 4.

Of the four alternatives that performed best in the

coarse filter assessment, alternative 10 provided the largest

level of potentially available LWD volume at the end of the

120-year simulation, with a value of 1,369 ft3. Alternative

11 also warranted consideration, as it provided the largest

level of potentially available LWD at the end of the 120-

year simulation of all of the viable alternatives, with a

value of 1,761 ft3. While this alternative did not perform as

well as others in the initial template assessment, it still met

the minimum criteria, and its higher LWD volume made it

a desirable second option.

Two preferred options emerged from the fine filter

assessment: alternatives 10 and 11. Both alternatives called

for the 60-hold prescription in the 25-ft bank stability zone.

Alternative 10 had a wider total buffer width of 80 ft, but

Figure 4—Potentially available LWD volume over time for the 12 viable template alternatives. Alternative 10 had the largest final volume of the four

alternatives that performed best in the coarse filter assessment, and alternative 11 had the largest final volume of all viable alternatives.
89

Figure 5—Using the fine filter criterion, two preferred alternatives emerged: alternative 10 and alternative 11. These became Option A

and Option B respectively for the template. Option A had a wider buffer but allowed a regeneration harvest outside the bank stability

zone, whereas Option B had a narrower buffer but allowed no further entries after the third thinning.

Figure 6—Management diagram for the two template options showing target stand density by stand age. The solid lines show the trajectory

of the 100-year rotation, while the dashed lines show the 60-hold density floor for the bank stability zone and the 25-hold density floor for

the remainder of the buffer under Option B.
allowed a regeneration harvest outside the bank stability

zone (100-year prescription). Alternative 11 had a narrower

total buffer width of 50 ft but did not allow additional

entries after the third commercial thin (25-hold prescription). These alternatives then became Option A and Option

B, respectively, in a template that gives landowners a

choice between two different approaches (fig. 5).

Stand density targets were plotted by stand age for the

two template options in figure 5 to provide a density management diagram (fig. 6). The solid line shows the management trajectory for the 100-year rotation, with the dashed

lines showing the 60-hold density floor for the bank stability zone and the 25-hold density floor for the remainder of

the buffer under Option B. To refine this prescription into

template form, a density range of plus or minus ten percent

was added for operational flexibility. Likewise, a 10-year

thinning window of plus or minus five years was added for

timing flexibility to coordinate with market conditions or

other operations. The target density for the third thinning

was also increased to 35 TPA, to address concerns that

thinning to 25 TPA may be too heavy. The resulting template specifying desired management ranges is shown in

figure 7. The shaded area in figure 7 suggests stand conditions which are likely to respond well to the template prescription. Stands beyond this area may be unstable from

growing at high densities for too long (Wilson and Oliver

2000) or may not have the capacity to produce a growth

response if thinned heavily. Additional factors, such as

height/diameter ratio or live crown ratio, should be considered before applying the template prescription to stands

beyond the shaded region.

RIPARIAN TEMPLATE APPLICATIONS

The final riparian management template provides useful

guidance for landowners in Washington and Oregon who

have overstocked riparian stands and wish to pursue an

alternative management plan. For mid-high site stands with

conditions that are within the candidate region illustrated in

90

Figure 7—The example management template, with a density range of ± ten percent and a thinning window of ± 5 years for operational and

timing flexibility. The shaded region indicates the stand conditions that are best suited for this template. For stands outside of this region,

other factors should be considered before applying the template prescription.
figure 7, the analysis suggests that either of the template

options could significantly increase the structural similarity

to the DFC over a 140-year time period while also providing an acceptable economic return. Both have been rigorously developed and evaluated by assessment procedures.

It should be cautioned, however, that this template has not

received regulatory approval. Landowners who wish to

implement this template should work with the appropriate

agencies to ensure that all regulatory requirements are met.

Longer-term permits may also be needed to fully implement the template as a long-term riparian management

plan.

The template described serves as an important demonstration of an objective, data-driven process that can be

used to develop templates for situations in which desired

outcomes (economic and environmental) can be quantified.

Additional riparian templates can be developed for different site classes or for hardwood stands. A number of upland

applications also exist for templates, including their use to

increase biodiversity in intensively managed plantations. It

is important to recognize that no single template can provide all biodiversity needs. Rather, a range of different

template options is needed for application across a landscape, as applying the same management prescription over

a broad region will ultimately decrease the landscape 

heterogeneity, with a subsequent decrease in diversity

(Bunnell and Huggard 1999). An effective template should

be broadly applicable in order to be useful over a significant number of acres, while at the same time the range of

appropriate template application should be limited, recognizing that one size does not fit all. Finally, a degree of

template flexibility will always be necessary to accommodate site-specific needs within a regulatory context.

UPLAND HABITAT MODELING: 

A CASE STUDY

The biodiversity pathways discussed above in the context of riparian management alternatives were originally

developed with a greater focus on creating upland habitat

for species sensitive to the conditions found in older forests

such as the spotted owl. The opportunity exists to treat

managed stands to provide wildlife habitat for a wide

diversity of both game and non-game species. Many types

of wildlife habitat models have been developed that can

estimate both habitat quality and quantity based on tree

lists and forest structure attributes available from existing

forest inventory data. There are direct parallels between

biodiversity pathway approaches for uplands management

and the challenges faced in development of effective riparian strategies. Treatments can be designed to focus on the

objectives of a single species or multiple species of local

interest while creating a sustainable, albeit diminished,

flow of timber. 

We illustrate this with a case study carried out to meet

the wildlife mitigation agreement on the Satsop Forest in

southwestern Washington (Ceder 2001, Marzluff et al.

2002). This project focused on the habitat needs of five

species, using previously defined Habitat Suitability Index

(HSI) models and the Habitat Evaluation Procedure (HEP)

used by Washington Department of Fish and Wildlife

(USDI 1980). The species were chosen to track changes 

in a variety of habitat types: spotted towhee (Pipilo erythrophthalmus) in brush habitats; Cooper’s hawk (Accipiter

cooperii) in mixed hardwood and conifer forests; southern

red-backed vole (Clethrionomys gapperi) in closed canopy

forests; pileated woodpecker (Dryocopus pileatus) in

mature forests; and black-tailed deer (Odocoileus hemionus

columbianus), a habitat generalist, across a range of structures. The Landscape Management System (LMS) was

used with links to the habitat models to estimate current

and future habitat conditions responsive to forest growth

and alternative management treatments. 

Twenty potential management alternatives for Satsop

Forest were developed ranging from a no-management

control to 40-year regeneration harvests with varying

amounts, timings, and levels of thinning between these

extremes. Assessments of each alternative determined the

amount of habitat for each species and wood volume that

could be produced over an 80-year planning horizon.

Results indicated the amounts of available habitats, similar

to no management or passive management, that could be

created through active management (fig. 8). Cooper’s

hawk, southern red-backed vole, and spotted towhee habitat values changed relatively little as harvesting increased.

In contrast, habitat available for the pileated woodpecker,

which is associated with older forest structures, generally

decreased with high harvest levels but was increased with

some management. 

Figure 8 shows that reducing the harvest (and timber

revenue) by approximately 50 percent can result in

increased woodpecker habitat compared to no harvest at

all. When the harvest constraints are large, as in this case 

to affect increases in woodpecker habitat, the incentive

needed for private managers to adopt such management

approaches with associated costs will also be large. If costly

habitat protections are imposed through regulation in

absence of compensation, the likelihood of forest conversions on private lands increases. 

91
per year to compensate the owner for their loss. While

incentives may be needed for biodiversity pathways, the

incentives are substantially less than the compensation needed for a no-harvest reserve which for our example is $81 per

acre per year even though it cannot achieve the targeted ecological objective as fast as the biodiversity pathway. If the

ecosystem service value of achieving the habitat target is 

at least $29 per acre per year, society should be willing to 

provide the incentive for the bio-pathway.

HABITAT MODEL USES AND

LIMITATIONS

There are many habitat models available that are sensitive to forest structure and hence management treatments

such as those developed by Johnson and O’Neil (2001).

92

Figure 8—Habitat and volume production for 20 potential 80-year management alternatives for Satsop Forest. 

POTENTIAL NEED FOR ECONOMIC

INCENTIVES

To determine the costs of increasing habitat is a straightforward process of comparing the landowner return for

alternatives that meet the habitat objectives with those that

meet commercial objectives. Determining the societal

value of meeting the objectives is more complex and currently a difficult political or regulatory decision. As a simplified example, to aid in understanding the cost, a generic

biodiversity pathway including three thinnings and a harvest in 100 years produces an SEV of $420 compared to

$1000 for a short commercial rotation involving a single

commercial thinning (table 4). This $580 loss to the landowner would require an incentive payment of $29 per acre
Empirical models can be derived from tree measures, as

with the bird population models of Hansen (1995), who

generated regression models relating trees per acre in specific diameter classes to bird population. The Washington

State Department of Natural Resources has quantified nesting, roosting, and foraging habitats for the northern spotted

owl based on tree and snag measures7.

Models of choice will be dependent upon the region and

species of interest. Appropriate models provide managers

and planners with the ability to analyze many alternatives

quickly while holding all other assumptions constant. This

consistency in assumptions provides uniform comparability

between simulations so that relative tradeoffs between

treatment alternatives can be assessed. 

Key limitations to the use of habitat models include the

lack of understory models that are compatible with forest

growth models and the need for more research to fieldverify the target attributes of habitat models. Understory

vegetation is a key component for many wildlife species

and associated models. Local understory relative to overstory relationships can be developed to derive mean values

for understory measures for each forest cover type, as was

done for the Satsop Forest project. Lack of regional models, however, increases the cost and complexity of analysis

and limits broader application to inform policy decisions.

With these limitations in mind, habitat analysis using available modeling capabilities implemented in LMS, or other

forest simulation tools, can provide useful predictive capability to assess habitat availability, risks to habitat, and

communicate the potential tradeoffs among different treatments and management strategies. Further, in a modeling

framework, outputs developed from habitat analysis can be

linked to evaluations of economic impacts expected from

management alternatives. Other important public values

can be assessed as well, such as forest health and carbon

sequestration.

CONCLUSIONS

Management alternatives employing thinning treatments have been shown to produce old forest structures

more effectively and at a lower cost than no-management

reserves or buffers. Such alternatives are needed to meet

ecological objectives while supporting an acceptable rate 

of return to discourage land conversion. Management templates based on an exhaustive analysis of simulation alternatives can simplify the identification of best treatments 

for practical implementation. Analysis of riparian habitat

enhancement opportunities has been shown to benefit from

similar modeling methodologies as those developed for

upland ecosystem management; however, the assessment of

tradeoffs between species of greatest interest, the amount

of habitat needed, how much revenue can be foregone, and

who pays can become complex. Alternatives are being

evaluated for reducing costs of habitat enhancement

through thinnings but longer rotations to provide the complexity of older forests will not likely be provided by private managers without incentives to compensate for lost

revenues. 

LITERATURE CITED

Bare, B.B.; Lippke, B.R.; Xu, W.; Oliver, C.D.; Moffet, 

J.; Waggener, T.R. 1997. Demonstration of Trust

Impacts from Management Alternatives to Achieve

Habitat Conservation Goals on Washington Department

of Natural Resources Managed Lands. Seattle, WA:

College of Forest Resources, University of Washington,

60 p. plus Appendices.

Bilby, R.E.; Bisson, P.A. 1998. Function and distribution 

of large woody debris. In: Naiman, R.J.; Bilby, R.E.,

eds. River ecology and management: lessons from the

Pacific coastal ecoregion. New York: Springer-Verlag:

324-346.

Bunnell, F.L.; Huggard, D.J. 1999. Biodiversity across 

spatial and temporal scales: problems and opportunities.

Forest Ecology and Management. 115: 113-126.

Carey, A.B.; Lippke, B.R.; Sessions, J. 1999. Intentional 

ecosystem management: managing forests for biodiversity. Journal of Sustained Forestry. 9: 83-125.

93

Table 4—Soil expectation value (SEV) for commercial

and habitat treatments and the incentive needed to offset losses

Incentive/

Treatment SEV/acre acre/year

- - - - - Dollars - - - - - - 

50 yr commercial rotation 1000 0

100 yr biopathway 420 29

No harvest (after stocking) -615 81

7 Washington Administrative Code (WAC) 222-16-085
Carey, A.B.; Lippke, B.R.; Sessions, J.; Chambers, C.J.; 

Oliver, C.D.; Franklin, J.F.; Raphael, M.J. 1996.

A pragmatic, ecological approach to small-landscape 

management. Compiled for the Washington Forest

Landscape Management Project. Phase II Report.

Sponsored by USDA Forest Service and Washington

Department of Natural Resources, with support from

the faculty of University of Washington and Oregon

State University.

Ceder, K.R. 2001. Using silviculture to sustain wildlife 

habitat: assessing changes and trade-offs in forest habitats using a habitat evaluation procedure within the

Landscape Management System. Seattle, WA: College

of Forest Resources, University of Washington. 82 p.

M.S. thesis.

Chan, S.; Anderson, P.; Cissel, J.; Larsen, L.; 

Thompson, C. 2004. Variable density management in

riparian reserves: lessons learned from an operational

study in managed forests of western Oregon, USA.

Forest Snow and Landscape Research. 78: 151-172.

Gehringer, K.R. 2005. An individual tree simulation 

model for estimating expected values of potentially

available large woody debris. Seattle, WA: College 

of Forest Resources, University of Washington. 77 p.

http://www.ruraltech.org/pubs/reports/lwd_gehringer/

lwd_gehringer.pdf (Accessed July 2005).

Gehringer, K.R. 2006. Structure-based nonparametric 

target definition and assessment procedures with an

application to riparian forest management. Forest

Ecology and Management. 223: 125-138. 

Hann, D.W.; Hester, A.S.; Olsen, C.L. 1997. ORGANON 

user’s manual. 6th ed. Corvallis, OR: Department of

Forest Resources, Oregon State University. 133 p.

Hansen, A.J.; McComb, W.C.; Vega, R.; Raphael, M.G.; 

Hunter, M. 1995. Bird habitat relationships in natural

and managed forests in the west Cascades of Oregon.

Ecological Applications. 5: 555-569.

Johnson, D.H.; O’Neil, T.A. 2001. Wildlife habitat 

relationships for Washington and Oregon. Corvallis,

OR: Oregon State University Press. 768 p.

Klemperer, D.W. 1996. Forest resource economics and 

finance. New York: McGraw Hill. 551 p.

Lippke, B.R.; Sessions, J.; Carey, A.B. 1996. Economic 

analysis of forest landscape management alternatives:

final report of the working group on the economic analysis of forest landscape management alternatives for the

Washington Forest Landscape Management Project.

CINTRAFOR Special Paper 21. Seattle, WA: College

of Forest Resources, University of Washington. 157 p.

Marzluff, J.M.; Millspaugh, J.J.; Ceder, K.R.; Oliver, 

C.D.; Withey, J.; McCarter, J.B.; Mason, C.L.;

Comnick, J. 2002. Modeling changes in wildlife habitat and timber revenues in response to forest management. Forest Science. 48: 191-202.

McCarter, J.B.; Wilson, J.S.; Baker, P.J.; Moffett, J.L.; 

Oliver, C.D. 1998. Landscape management through

integration of existing tools and emerging technologies.

Journal of Forestry. 96: 17-23.

Meleason, M.A.; Gregory, S.V.; Bolte, J. 2003.

Implications of selected riparian management strategies

on wood in Cascade Mountain streams of the Pacific

Northwest. Ecological Applications. 13: 1212-1221.

Talbert, C.; Marshall, D. 2005. Plantation productivity 

in the Douglas-fir region under intensive silvicultural

practices: results from research and operations. Journal

of Forestry. 103: 65-70.

U.S. Department of Interior [USDI]. 1980. Habitat 

evaluation procedures 102 ESM. Washington, DC: U.S.

Department of Interior Fish and Wildlife Service. 

Washington State Department of Natural Resources 

[WDNR]. 2004. Final environmental impact statement

on alternatives for sustainable forest management of

state trust lands in western Washington. Olympia, WA:

Washington State Department of Natural Resources. 

Wilson, J.S.; Oliver, C.D. 2000. Stability and density 

management in Douglas-fir plantations. Canadian

Journal of Forest Research. 30: 910-920. 

Zobrist, K.W.; Gehringer, K.R.; Lippke, B.R. 2004. 

Templates for sustainable riparian management on family

forest ownerships. Journal of Forestry. 102: 19-25.

Zobrist, K.W.; Gehringer, K.R.; Lippke, B.R. 2005. 

A sustainable solution for riparian management. In: Deal,

R.L.; White, S.M., eds. Understanding key issues of

sustainable wood production in the Pacific Northwest.

Gen. Tech. Rep. PNW-GTR-626. Portland, OR: U.S.

Department of Agriculture, Forest Service, Pacific

Northwest Research Station: 54-62.

94
1 Greg Latta is Senior Faculty Research Assistant and 2 Clair A. Montgomery is Professor, Department of Forest Resources, Oregon State University,

Corvallis, OR 97331.

Managing for Wildlife Haitat in Westside Production Forests

ECONOMIC CONSIDERATIONS IN MANAGING 

FOR OLDER-FOREST STRUCTURE

Greg Latta1 and Claire A. Montgomery2

INTRODUCTION

For several high-profile wildlife species of concern 

in the Pacific Northwest, old-growth conifer forest is a critical component of habitat. But its area is dwindling. While

these forests may once have covered 30 percent to 70 percent of the western Oregon coastal-forested landscape

(Teensma et al. 1991, Wimberly et al. 2000), it is estimated

that they now account for only about 5 percent (Spies et al.

2002). Concern about this loss has fueled a number of

responses that seek to preserve and enhance the area of

older forest on production forests of the Pacific Northwest.

We believe that, regardless of the goal of a conservation

program or the means by which it may be implemented,

the more cost-effective it is, the more likely it will be

accepted and implemented.

In three recent studies by forest economists at Oregon

State University, different aspects of cost-effective active

management for stands that are structurally similar to oldgrowth on private forest land in western Oregon have been

explored: (1) stand-level silvicultural regimes, (2) forestlevel targets for the area of structurally old forest, and (3)

the effectiveness of certification in achieving forest-level

targets.

ABSTRACT

Forest conomists at Oregon State University have been conducting analyses of cost-effective management for older forest

structure on private forest land in western Oregon. We describe three studies in this paper: a stand-level study, a forest-level

study, and a simulation of forest certification. We also present a case study in which a stand not part of the original study is

used to demonstrate how results from the stand-level study can be applied to a typical production forest stand in such a way

that generates more complex structure in a relatively cost-effective manner.

KEYWORDS: Management regimes, opportunity cost, older-forest structure.

95

In the first study, Latta and Montgomery (2004) used a

random search heuristic and an individual tree simulation

model, ORGANON (Hann et al. 1997), to search for costeffective old forest management regimes for a wide range

of stand types that occur on private land in western

Oregon. The regimes were required to meet older forest

structural criteria, defined by the Oregon Department of

Forestry (Oregon Department of Forestry 2001), for 30

years prior to clear-cut harvest. The opportunity cost of

managing for older forest structure was estimated for each

stand type as the value of forgone timber production under

maximum net present value management. Opportunity cost

was found to be positively correlated with site quality,

stand age, and stocking.

In the second study, Montgomery et al. (2006) examined the use of active management to achieve targets for

the area of private forest land in western Oregon that meet

these old forest structural criteria within a range of time

frames. The idea of area targets is consistent with standards

for sustainable forestry that include measures of the extent

of area in the full range of forest successional stages

(Montreal Process Working Group, http://www.mpci.org,

accessed in August 2004). A model of regional timber 
supply was used to search for cost-effective strategies to

reach these targets. The model provides a method for quantifying tradeoffs between the area and timing of alternative

targets. It was estimated that a target of 20 percent of private forest area that met older forest structural criteria

within 95 years could be achieved at an aggregate loss to

forest landowners and lumber and plywood manufacturers

of $341 million3; doubling the area target from 20 to 40

percent could increase cost 3.4 times and extending the

time horizon by 25 years could reduce the cost four-fold.

In the third study, Busby et al. (in press) used the same

regional timber supply model for western Oregon to simulate the response of private forest landowners to incentives

to certify their forest land. In the case of a $35 per acre certification bonus payment, 20 percent of the forest area was

certified within a 100-year time horizon; with a $69 per

acre certification bonus payment, 60 percent of the area

was certified. However, the ecological benefit of certification, measured in terms of forest area meeting older forest

structural criteria, was minimal.

In this paper, we use a case study to illustrate how

foresters can use the information from these studies, particularly Latta and Montgomery (2004), to meet sustainability

objectives related to older forest structure while generating

income from timber harvest. In the next section, a case

study stand is described. Stand development under three

different management regimes is simulated and costs compared. A discussion of factors leading to the type of older

forest structural management regime found in the studies

follows. The paper concludes with a brief discussion of the

trade-offs involved in identifying optimal versus pretty

good management regimes.

CASE STUDY

In the Latta and Montgomery (2004) study, management regimes were developed for a range of stands using

an optimization algorithm. While forest land managers are

unlikely to have access to such a program, it may be possible for them to generalize from the results of that study in

order to generate pretty good regimes for the stands they

manage. 

To illustrate, a 15-year-old, even-aged Douglas-fir stand

from Lincoln County, Oregon was selected. This stand was

not part of the original study. It was planted using a tenby-ten ft spacing and it currently has 474 trees per acre, 15

of which are hardwoods (97 percent of normal stocking;

USDA Forest Service 2000). The 50-year Douglas-fir site

index is 133 and the current quadratic mean diameter is 

4.9 in. 

Only a brief description of the growth and yield, silvicultural regimes, logging and other costs are provided here.

Additional details may be found in Latta and Montgomery

(2004). 

Silvicultural Regimes

Growth of the case study stand was simulated for 100

years under three different management regimes: one

designed to maximize the net present value of timber harvest with no other objective, one designed to maximize the

net present value of timber harvest while generating a stand

that meets older forest structural criteria within 125 years,

and one that set aside the stand in a reserve with no timber

management activities allowed. The first two regimes were

based on the optimization results published in Latta and

Montgomery (2004).

In tables 1 and 2, we show the average values reported

in Latta and Montgomery (2004) for number of years to

thinning and percent volume removed in up to three proportional thinnings from the optimized management

regimes that meet older forest structural criteria within 125

years. In table 1, the regimes are for newly regenerated

stands and, hence, years to thinning are stand ages. The

regimes are summarized for all stand types, by forest type,

by site class, and by ecological region. In table 2, the

regimes are for the 834 existing stands that were included

in the original study. Average number of thinnings is shown

because less than three thinnings were prescribed for some

stands. Again, these are summarized for all stand types, by

age class, and by stocking level. 

Ideally, a land manager, seeking to achieve older forest

structural criteria while maximizing the value of the stand,

would find the optimal regime for each existing stand using

an optimization algorithm. Or, as a second-best strategy,

the manager would identify the regime for the stand in the

original study that most closely approximates the stand that

is being managed. But this study demonstrates how the

published results can provide the basis for a pretty good

older forest structural regime.

96

3 All dollar values in the paper are in 2005 dollars.
In developing a pretty good older forest structure management regime, a manager could select and average the

applicable prescriptions from the categories presented for

newly regenerated stands (table 1) and/or older existing

stands (table 2). Prescription categories for regenerated

stands are: all stand types, forest type, site index, and ecological region (table 1). Similarly, prescription categories

for existing stands are: all stand types, age class, and percent of normal stocking (table 2). A manager could then

select an applicable prescription, or multiple prescriptions

from appropriate categories in tables 1 or 2 and then develop a composite thinning regime by averaging the 

97

Table 1—Silvicultural regimes for achieving older forest structure in 125 

years in newly regenerated stands 

Years until thinning / percent volume removed

Prescription Categories 1st thinning 2nd thinning 3rd thinning

All stand types 40 yr/63% 59 yr/56% 79 yr/40%

By forest type:

Douglas-fir 39 yr/63% 57 yr/62% 76 yr/46%

Other conifer 42 yr/63% 63 yr/48% 83 yr/32%

By site index:

Over 135 33 yr/61% 49 yr/63% 68 yr/52%

115 to 135 39 yr/61% 54yr /60% 76 yr/40%

95 to 115 45 yr/67% 65 yr/51% 85 yr/37%

95 and under 41 yr/60% 66 yr/54% 86 yr/30%

By ecological region:

West Coast Range 35 yr/61% 56 yr/54% 78 yr/38%

Other Coast Range 40 yr/66% 57 yr/62% 79 yr/34%

West Cascade Range 39 yr/61% 57 yr/55% 75 yr/49%

Klamath 55 yr/65% 73 yr/53% 89 yr/36%

Note: Years until thinning is equivalent to total stand age for regenerated stands.

Table 2—Silvicultural regimes for achieving older forest structure in 125 years in existing stands

Years until thinning / percent volume removed

Prescription Categories Thinnings 1st thinning 2nd thinning 3rd thinning

All stand types 2.6 18 yr/68% 39 yr/60% 72 yr/42%

By age class:

20 and under 2.5 31 yr/67% 51 yr/63% 78 yr/42%

20 to 40 2.6 12 yr/68% 34 yr/59% 69 yr/43%

40 to 60 2.6 5 yr/68% 28 yr/58% 68 yr/40%

60 to 80 2.8 4 yr/69% 28 yr/58% 71 yr/36%

over 80 2.9 6 yr/69% 35 yr/56% 67 yr/42%

By percent of normal stocking:

40 percent and under 2.6 28 yr/67% 50 yr/61% 77 yr/43%

40 to 120 percent 2.6 11 yr/68% 32 yr/60% 68 yr/40%

over 120 percent 2.5 6 yr/68% 28 yr/56% 68 yr/42%

values for 1) years until thinning and 2) percent volume

removed.

To illustrate this process, we show in table 3 the applicable thinning prescriptions from tables 1 and 2 that relate

to the case study stand. Activites in table 3 are presented 

at total stand age. Simply averaging these prescriptions and

rounding to the nearest five yields the following prescription: 65 percent volume removed at age 35, 60 percent volume removed at age 55, and 40 percent volume removed 

at age 80. We also simulated this stand as if it was set 

aside as a reserve for 100 years and as if it was managed for
The reserve regime generates the highest volume. But 

it does not generate financial value because it is never 

harvested. Therefore, the opportunity cost of the reserve

option is the total value of the stand under the net present

value regime. 

The older forest structural regime has heavier than traditional thinning intensities that occur early in the life of

the stand and final harvest age is far greater than financial

maturity. This reduces the value of the stand from the maximum net present value regime. The heavy thinnings generate value early, but even so, the opportunity cost of older

forest structural management is substantial. For example,

over 50 percent of the value of the stand is foregone with 

a discount rate of 6 percent.

Stand Structure

To evaluate whether structural criteria were being met,

we used the Stand Visualization System (McGaughey

1997). In figure 1, the stand development at 20-year intervals over the 100-year time horizon is shown for each of

the three management regimes. The first 20 years (i.e., to

age 35 years) are identical for all three regimes. 

At 40 years into the simulation, however, the disparate

paths of the three regimes become evident. The 55-year-old

reserve stand is very dense and the crowns have receded up

the boles of the trees, leaving little live crown per tree. The

net present value stand was clearcut at 40 years of age, 25

years into the simulation, leaving a fully stocked 15-yearold stand. The 55-year-old older forest structure stand has

been thinned just following the stand representation at 20

years old with a volume removal of 65 percent. The opening up of growing space in the stand has allowed the larger

trees to retain lower branches resulting in longer crowns

than the reserve stand. 

maximum net present value of timber harvest. The latter

regimes involves a clearcut timber harvest every 40 years

and no thinnings. 

Economic Returns

An important aspect of valuing forest stands is accounting for the time value of money. Because returns on forestry investment alternatives occur in varying years and far

in the future, the methodology employed in determining

the present value of those alternatives is important. To simplify this analysis, we used a simple discounting formula

for each of the thinning and final harvest returns for each

of the three regimes. The financial value of the growing

stock was evaluated at the end of the 100-year time horizon

and discounted to present. Because each dollar in 2106 is

worth only one third of a penny in 2006, this is a valid

approximation of the total stand value.

In table 4, the volume and value of the removals under

each of the three regimes are shown, along with the value

of the standing inventory at the end of 100 years. These

values were discounted using three different interest rates:

4-, 6-, and 8-percent. Log price is an average of #2 and #3

sawlog prices projected for a 50-year base case in a recent

western Oregon timber supply study (Adams et al. 2002).

Logging costs were computed using equations from Fight

et al. (1984) that take volume per acre and average diameter into account. Haul cost was assumed to be $59 per

thousand board ft. For the net present value regime, we

included a $441 per acre planting cost. 

The net present value regime represents the highest

return possible to the landowner given the growth, yield 

and costs associated with the stand. Any deviation from this

management is an opportunity cost borne by the landowner;

the landowner is giving up income by choosing to manage

for some non-market objectives. 

98

Table 3—Silvicultural regimes for the case study stand from tables 1 and 2 

Years until thinning / percent volume removed

Prescription categories (from tables 1 and 2) 1st thinning 2nd thinning 3rd thinning

Table 1, all stand types 40 yr / 63% 59 yr / 56% 79 yr / 40%

Table 1, forest type, Douglas-fir 39 yr / 63% 57 yr / 62% 76 yr / 46%

Table 1, Site index, 115-135 33 yr / 61% 49 yr / 60% 68 yr / 40%

Table 1, Ecological Region, West Coast Range 35 yr / 61% 56 yr / 54% 78 yr / 34%

Table 2, all stand types 33 yr / 68% 54 yr / 60% 87 yr / 42% 

Table 2, age class, < = 20 46 yr / 67% 66 yr / 63% 93 yr / 42%

Table 2, percent of normal stocking 40-120 percent 26 yr / 68% 47 yr / 60% 83 yr / 43%

Averages 36 yr / 64% 55 yr / 59% 81 yr / 41%

Note: Years until thinning is equivalent to total stand age for the case study stand, which is 15 years old at the start of the simulation.
At 60 years into the simulation, the 75-year-old reserve

stand looks structurally much as it did at age 55 years, with

a dense single story and short crowns. The largest trees in

the stand are just under 28 in diameter at breast height

(DBH). The net present value stand is once again 5 years

from a regeneration harvest. The older forest structure

stand has been thinned again removing another 60 percent

volume removal. The understory has the light required for

development of a new cohort. The 75-year-old older trees

have retained much of their live crown, providing for

greater diameter growth. There are just under 5 trees per

acre with greater than 32 in DBH.

At 80 years, the 95-year-old reserve stand now has 16

trees per acre larger than 32 in DBH, yet with the dense

canopy it has limited ability to generate an understory of

any kind. The net present value stand is once again at 15

years of age. The older forest structure stand just received

its final thinning, a 40 percent volume removal. The stand

has a well-established younger cohort (age <20 years) and

still has 6 trees per acres of 95-year-old trees larger than 

32 in DBH following the final removals. 

Finally at 100 years, the 115-year-old reserve stand has

over 30 trees per acre that are larger than 32 in DBH. The

largest tree is just under 38 in DBH. Despite its size, there

is not much diversity in this stand. The canopy closure is

89 percent, compared to the 51 percent for the older forest

structure stand, letting little light down to the forest floor to

99

support understory vegetation. In contrast, the older forest

structure stand has at least two distinct cohorts, with over 

9 trees per acre greater than 32 in DBH. The largest trees

(115 years old) are over 45 in DBH. 

DISCUSSION

This case study reinforces silviculturists’ concerns 

that the young fully stocked production forests of today

may not develop into the natural old-growth forests we 

are familiar with if left unmanaged in reserves (Andrews

et al. 2005). They may instead develop into dense overstocked forests with increased risk of fire, insects, and disease. To hasten the development of large trees and multiple

cohorts it may be necessary to employ thinning regimes

which appear extreme when compared to the traditional

commercial or uneven-aged stand removal levels

(Tappeiner et al. 1997, Carey and Curtis 1996). 

There are several factors leading to the selection of

multiple heavy thinnings as a silvicultural pathway to older

forest structure. It is notable that the management regimes

developed to meet older forest structural criteria while

maximizing the financial value of the stand are very similar

to management regimes developed by silviculturists who

ignored economic criteria (e.g. McComb et al. 1993, Carey

and Curtis 1996, Barbour et al. 1997). This is because the

silviculture, logging cost dynamics, and economics all push

the optimization toward the same type of regime. 

Table 4—Economic returns per acre case study stand for three management strategies

Volume Logging Discounted value at 

Stand removed cost

Year age (mbf) ($/mbf) Revenue 4 6 8

- - - - - - -Percent - - - - - - -

Older forest structure

2026 35 10.1 146 3,384 1,544 1,055 726

2046 55 12.6 95 4,793 998 466 221

2071 80 6.4 81 2,510 196 57 17

2106 115 62.8 68 25,272 500 74 11

Total 92 35,960 3,239 1,653 975

Reserve

2106 115 138.7 60 56,793 1,124 167 26

Net present value

2031 40 35.5 96 12,998 4,876 3,029 1,898

2071 40 35.5 96 12,998 1,016 294 87

2106 35 24.8 117 8,948 177 26 4

Total 96 34,944 6,069 3,349 1,989
100

Figure 1—Stand Visualization System representations of the Older Forest Structure (OFS) Management, Reserve, and Net Present

Value (NPV) Maximization regimes for the case study stand in 20 year intervals for 100 years.
Silvicultural Considerations

Silviculturally, the use of heavy thinning promotes

diameter growth and creates openings in which seedlings

can survive and ultimately develop into a second story. In

crowded stands, encroachment of a tree’s growing space

causes the shaded limbs to die and eventually fall off.

Increasing a tree’s growing space by thinning reduces

crown recession, which leads to longer and wider crowns

over time; larger crowns lead to faster diameter growth. To

illustrate, we simulated the diameter growth of the ten

largest trees per acre in our case study stand following a

thinning of varying intensity administered at age 35 (fig.

2). Diameter growth is increased with each increment in

the intensity of the thinning. Note that the effect on diameter growth is greater for an increase from 50 to 70 percent

volume removal than it is for an increase from 30 to 50

percent. Also note that the effect of the first 10 percent

removal is relatively small; this is because the stands return

quickly to being fully stocked after such a light thinning.

A reduction of density may not always lead to such a

pronounced change in diameter growth. If the pre-thinning

stand does not have enough live crown to respond to the

newly opened space, it will require years to develop the

leaf area necessary to support increased diameter growth.

Operational Considerations

Operationally, while thinning costs more per unit volume than final harvest, there are economies of scale leading to lower unit costs for heavier thinnings. The logging

cost equations used in this study are based on Fight et al.

(1984). He found that logging costs are inversely related to

both average tree diameter and volume per acre. The reduction in cost as the intensity of thinning increases is due in

part to increases in efficiency in felling and yarding and to

a lesser extent the spreading of the fixed costs, such as

moving equipment in, over a larger volume of removals.

To illustrate, we computed unit logging costs for a

range of stand conditions (table 5) and thinning intensities.

The stands are fictional uniform stands of 100, 300, or 500

trees per acre with DBH of 10, 12, and 16 in. The stands

are described in the left hand side of the table. Logging

costs in dollars per thousand board ft for a range of thinning intensities are shown on the right hand side. In general, these costs decrease as the logs get bigger or as the

thinning intensity increases.

Economic Considerations

Finally, the time value of money refers to the fact that,

all things equal, a dollar today is preferable to a dollar

101

Figure 2—Quadratic mean DBH of the ten largest trees per acre following a thinning at age 35 for a range of

% volume removals.
received some time in the future. This is an important concept in valuation of a forest investment because the time

horizon of forest investment is typically very long. To illustrate the importance of the time value of money, the present

value of one dollar received up to 100 years in the future 

is shown in figure 3 for discount rates of 4-, 6-, and 8-percent. Economic returns, even one rotation out, have very

limited value today. Even when considering a rather conservative discount rate of four percent, a dollar 50 years in

the future would only be worth fourteen cents today, and 

at 100 years it would be worth just under two pennies. This

discounting gives preference to positive events, such as

thinning revenue, happening sooner in the future rather

than later.

102

Table 5—Logging cost variation for differing stand attribute and removal levels

Stand attributes Logging cost ($ / mbf) based on 

Stand Basal percentage of stems removed

Number Diameter density area Thousand

of trees (in) indexa (square ft) board ft Cubic ft 100 70 40 10

100 10 100 55 3 1426 249 265 299 493

300 10 300 164 10 4277 208 221 242 322

500 10 500 273 17 7129 196 203 223 284

100 12 134 79 7 2291 149 159 176 271

300 12 402 236 22 6873 127 132 145 188

500 12 670 393 37 11455 122 125 133 169

100 16 213 140 18 4623 79 84 93 132

300 16 638 419 55 13870 71 73 76 98

500 16 1063 698 92 23117 69 70 73 89

a Reineke, L.H. 1933. Perfecting a stand-density index for even-aged forests. Journal of Agricultural Research. 46: 627-638.

Figure 3—Present value of one dollar received up to 100 years in the future.
CONCLUSION

We utilized a case study of a typical young even-aged

production forest stand to compare stand development

under a silvicultural regime designed to increase the development of older forest structure while minimizing the economic impact to a regime designed to maximize the net

present value of the stand. We also compared it to a forest

reserve. We based the older forest structure regimes on

published results from a study in which least cost old forest

structural regimes were identified for a range of stand types

on private land in western Oregon. It that study, the opportunity cost of old forest structure (the present value of forgone timber harvest revenue when old forest structural

criteria are imposed) was found to average around 30 percent of the maximum net present value of the stands in the

study. In our case study, in which we simply applied average values for the timing and intensity of thinnings, the

value loss associated with old forest structure was about 50

percent. While it would be nice if, in practice, you could

simply go to a table from a published study and find a

management regime that would work for a particular stand,

we found a potential gain of 20 percent between an optimized regime and a non-optimized regime. 

The ideas portrayed in this case study can serve as a

rule of thumb in developing a regime to generate old forest

structure in an economic way. As any forester knows,

though, every stand is a little different, and adjusting for

those differences can matter. 

ACKNOWLEDGMENTS

The research reported in this paper was supported by

the Department of Forest Resources at Oregon State

University, the Oregon Department of Forestry, and the

USDA Forest Service’s Sustainable Wood Production

Initiative. We are grateful to Tim Harrington, Gretchen

Nicholas, and Nathan Poage for comments and suggestions

during the writing of this paper.

LITERATURE CITED

Adams, D.M.; Schillinger, R.A.; Latta, G.; Van Nalts, A.

2002. Timber harvest projections for private land in

western Oregon. Contrib. 37. Corvallis, OR: College 

of Forestry, Oregon State University.

http//fcg.cof.orst.edu/rc/rc37.pdf

Andrews, L.S.; Perkins, J.P.; Thrailkill, J.A.; Poage, 

N.J.; Tappeiner, J.C. 2005. Silvicultural approaches to

develop northern spotted owl nesting sites, Central

Coast Ranges, Oregon. Western Journal of Applied

Forestry. 20: 13-27.

Barbour, R.J.; Johnston, S.; Hayes, J.P.; Tucker, G.F. 

1997. Simulated stand characteristics and wood product

yields from Douglas-fir plantations managed for

ecosystem objectives. Forest Ecology Management. 

91: 205-219.

Busby, G.M.; Montgomery, C.A.; Latta, G.S. [In press]. 

The opportunity cost of forest certification on private

land in western Oregon. Western Journal of Applied

Forestry. 

Carey, A.B.; Curtis, R.O. 1996. Conservation of biodiversity: a useful paradigm for forest ecosystem management. Wildlife Society Bulletin. 24: 610-620.

Fight, R.D.; Ledoux, C.B.; Ortman, T.L. 1984. Logging 

costs for management planning for young-growth coast

Douglas-fir. Gen. Tech. Rep. PNW-176. Portland, OR:

U.S. Department of Agriculture, Forest Service, Pacific

Northwest Range and Experiment Station. 10 p.

Hann, D.W.; Hester, A.S.; Olsen, C.L. 1997. ORGANON 

user’s manual. 6th ed. Corvallis, OR: Forest Resources

Department, Oregon State University. 135 p.

Latta, G.; Montgomery, C.A. 2004. Minimizing the cost 

of stand level management for older forest structure in

western Oregon. Western Journal of Applied Forestry.

19: 221-231.

McComb, W.C.; Spies, T.A.; Emmingham, W.H. 1993. 

Douglas-fir forests: managing for timber and matureforest habitat. Journal of Forestry. 91: 31-42.

McGaughey, Robert J. 1997. Visualizing forest stand 

dynamics using the stand visualization system. In:

Proceedings of the 1997 ACSM/ASPRS Annual

Convention and Exposition; April 7-10, 1997. 

Seattle, WA. Bethesda, MD: American Society of

Photogrammetry and Remote Sensing. Vol. 4: 248-257.

Montgomery, C.A.; Latta, G.S.; Adams, D.M. 2006. The 

cost of achieving old-growth forest structure. Land

Economics. 82: 240-256.

103
Oregon Department of Forestry. 2001. Northwest

Oregon state forests management plan: final plan.

Salem, OR: Oregon Department of Forestry. 501 p.

Spies, T.A.; Johnson, K.N.; Reeves, G.H.; Bettinger, P.; 

McGrath, M.; Olsen, K. 2002. An evaluation of the

compatibility of wood production and ecological

integrity in the Oregon Coast Range. In: Johnson, A.C.;

Haynes, R.W.; Monserud, R.A., eds. Congruent management of multiple resources: proceedings from the

Wood Compatibility Initiative workshop. Gen. Tech.

Rep. PNW-GTR-563. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest

Research Station: 111-120.

Tappeiner, J.C.; Huffman, D.; Marshall, D.; Spies, T.A.; 

Bailey, J.D. 1997. Density, ages, and growth rates in

old-growth and young-growth forests in coastal Oregon.

Canadian Journal of Forest Research. 27: 638-648.

Teensma, P.D.A.; Rienstra, J.T.; Yeiter, M.A. 1991. 

Preliminary reconstruction and analysis of change in

forest stand age classes of the Oregon Coast Range

from 1850 to 1940. Tech. Note T.N. OR-9. Portland,

OR: U.S. Department of Interior, Bureau of Land

Management. 11 p.

USDA Forest Service. 2000. Documentation of inventory 

procedures and compilation routines: western Oregon.

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

Service, Pacific Northwest Research Station, Forest

Inventory and Analysis Program. 48 p.

Wimberly, M.A.; Spies, T.A.; Long, C.J.; Whitlock, C. 

2000. Simulating historical variability in the amount of

old forests in the Oregon Coast Range. Conservation

Biology. 14: 167-180.

104
INTENSIVELYMANAGED FORESTS
This page is intentionally left blank.
1 Ken L. Risenhoover is Wildlife Program Manager and 2 S. Blake Murden is a Wildlife Biologist, Port Blakely Tree Farms, L.P., 8133 River Drive SE,

Tumwater, WA 98501.

Managing for Wildlife Haitat in Westside Production Forests

MANAGING FOR WILDLIFE HABITAT IN 

INTENSIVELY-MANAGED FORESTS

Ken L. Risenhoover1 and S. Blake Murden2

INTRODUCTION

Foresters and landowners managing private forest

lands in the Pacific Northwest face numerous challenges.

Principal among these is remaining competitive in a rapidly

globalizing market, while at the same time contending with

increasing forest practices regulations. World demand for

wood and fiber continues to increase and it has stimulated

economic development around the world (Haynes 2003,

Shifley 2006). World demand also has stimulated markets

for alternative building products (e.g., glue-laminated

beams and steel studs). Changing supply and demand have,

in turn, impacted domestic and export markets, and ultimately, they affect what buyers are willing to pay for logs

(Franklin and Johnson 2004). More recently, increasing

ABSTRACT

Privately owned timberlands are an essential component of biodiversity conservation in the Pacific Northwest. Despite

public perceptions, these areas represent significant amounts of productive habitat that are important to sustaining a large

variety of wildlife species. Management goals in working forests differ from those employed on public lands. Private forest

lands play an important role in providing the wood products needed by society, and wood production is a primary goal

influencing how they are managed. Managed forests provide a variety of young to intermediate stand age classes and provide considerable habitat diversity for species adapted to these conditions. Primary differences between managed and

unmanaged forest are the result of differences in the frequency and intensity of disturbance patterns. Although managed

stands typically lack the structural diversity present in unmanaged forests, within-stand habitat diversity can be enhanced 

in managed forests by retaining individual structures such as snags, downed logs and green trees from past rotations. In

managed forest landscapes, spatial diversity is a function of the size and distribution of stand age classes produced by the

pattern of harvest. Riparian management zones retained at harvest buffer streams and ensure maintenance of important ecological functions. As they develop, riparian areas will contribute late-successional habitat currently unavailable in managed

forests and will provide sources of large snags. Riparian areas also will facilitate animal movements and help sustain population viability. For conservation efforts to succeed, it is critical that the public, conservationists, and state and federal agencies gain a greater appreciation of the role privately-owned timberlands play in landscape management. 

KEYWORDS: Biodiversity, conservation, Pacific Northwest, retained structures, within-stand diversity.

107

fossil fuel prices have led to similar increases in logging

and transportation costs (e.g., road maintenance and fuels).

Collectively, these economic factors and declining log

prices reduce profit margins for landowners. Because

investment horizons in forestry are long-term compared to

other enterprises, they are more risky considering trends in

global markets and the political and regulatory uncertainty.

At the same time, timberland owners and managers

have experienced a steady increase in the number of regulations governing how forestry practices are carried out in

this region. Concerns about threatened and endangered

species such as the northern spotted owl (Strix occidentalis),

marbled murrelet (Brachyramphus marmoratus), and most

recently, the listing of several declining salmon populations
have led to additional regulations that have taken lands 

out of production. The growing human population in the

Pacific Northwest has effectively shifted the political 

agenda in states like Washington and Oregon from rural 

to urban and has changed public attitudes toward forestry

(Johnson and Stankey 2002). Unfortunately, changing

social values and political conflict have led to antagonism

between people making a living in forestry and other interest groups. As a result, there are a great many misconceptions about modern forest practices. 

Fortunately, the science of forestry and its application

has advanced considerably during the past 20 years (Hunter

1990, DeBell et al. 1997, Tappeiner et al. 2002). In addition, private timberland owners are taking a more active

role in conservation processes and they have voluntarily

accepted additional restrictions where credible science has

demonstrated the need for additional protective measures.

Clearly, the timber industry is concerned about public opinion and desires to reassure the public that they are practicing sustainable forestry. The recent “Forest and Fish

Agreement” in Washington (Washington Department of

Natural Resources et al. 1999) is one example of this

process. 

In our opinion, the majority of private timberland owners are in this business for the long haul. They are in touch

with the land they manage and they have an appreciation

for natural resources. Their reputations as good land stewards are important to them and practicing responsible

forestry is a source of pride. However, because many private timberland owners do not employ wildlife biologists,

they may not fully comprehend the objective of the rules

governing forest practices. Landowners would benefit from

assistance aimed at helping them to better understand the

scientific basis for forest practice regulations and to help

them to know how they can integrate conservation practices into their own management program.

In this paper, we discuss the role private forest lands

have in wildlife management and biodiversity conservation. In addition, we suggest a way of thinking about challenges confronting forest landowners, and suggest ways

they can improve their own practices to benefit biodiversity

on their ownership while minimizing impacts to forest

operations. It is important that foresters and landowners

adopt the philosophy that if they do a better job of applying

effective conservation measures, they will succeed in sustaining wildlife populations and thus, prevent the need for

additional regulations in the future. That would be a “winwin” situation for both timberland owners and biodiversity

conservation and should be the goal of landowners and

conservationists.

The Role of Managed Forests in the Conservation

Process

So how do we jumpstart the process needed to help

create this “win-win” scenario for landowners and natural

resource managers? First, society needs to recognize and

better understand the role private timberlands play in biodiversity conservation. How do the goals for managing privately-owned timberlands differ from those used to manage

public lands? As stated above, the primary management

goal for any private timberland owner is the production of

wood products. In the Pacific Northwest, working forests

play an important role in providing the wood products

needed by society. They also are an important part of local

and regional economies, especially in rural areas. Gebert et

al. (2002) reported Oregon’s primary and secondary wood

and paper products industry employed nearly 75,000 workers who earned an estimated $2.8 billion in annual income

in 1998. It is estimated that the United States utilizes more

than one-third of the industrial wood produced around the

globe, although it has only 5 percent of the world’s population (Oregon Forest Resources Institute 2003). Like many

other developed countries around the world, the United

States must import wood to meet its growing demand for

wood products. However, because the environmental standards regulating harvest and forest management in other

parts of the world are lower than they are in the Pacific

Northwest, there is a growing concern that we may be, in

effect, shifting the burden of environmental responsibility

elsewhere (Oregon Forest Resources Institute 2003, Shifley

2006). Thus, production forests in the Pacific Northwest

are very important and, without them, the public would be

left further dependent on imports to meet society’s current

and future demands for paper and wood products. 

Forest management goals in working forests are different from the goals that direct management decisions on

public lands (fig. 1). Management priorities for public

lands set aside as parks or wilderness areas often are related to protecting and conserving pristine, unique or otherwise sensitive areas and the fauna and flora that typically

inhabit those areas. Public lands managed by the U.S.

Department of Agriculture, Forest Service and the U.S.

Department of Interior, Bureau of Land Management in the

past have been managed for multiple uses that included

human recreation, the conservation of wildlife and natural

resources, but also management of renewable natural

resources such as timber. At the other extreme end of this

spectrum are private timberlands managed intensively for

108
production of wood fiber and other commercially-important products. Examples of this circumstance might include

poplar (Populus spp.) plantations or Christmas tree plantations. Generally, under these circumstances the frequency

and intensity of management activities may ultimately limit

the ability of these areas to support certain wildlife species

and native plants. Finally, there are those lands that are managed principally for timber production, but that are managed less intensively. When managed well, these forests

have the potential to contribute essential habitat for sustaining wildlife populations and biodiversity.

To remain competitive, private timberland owners

must be able to produce a reliable supply of a product that

is in demand in the world market. Their competitiveness

and survival is dependent on their profit margin and their

ability to produce a valuable product that can be sold in 

the world market. In the Pacific Northwest that product is

mostly Douglas-fir (Pseudotsuga menziesii var. menziesii)

saw logs. Douglas-fir is a native tree species that is prized

as an excellent building material due to its structural qualities (Megraw 1986). It is well-adapted to the climate and

moisture conditions in the temperate forest region. However,

Douglas-fir is shade intolerant and it requires direct sunlight to grow. When grown in even-aged stands the trees

grow quickly and tend to be free of limb knots and other

undesirable characteristics that reduce their value. There

are efforts and research underway to develop alternative

approaches to growing Douglas-fir using single-tree and

group selection harvest techniques (Carey et al. 1996, Curtis

1997, Franklin et al. 1997). Although they may prove successful in regenerating structurally-complex, uneven-aged

forest stands using these methods, the wood produced with

these methods may be relatively low grade and would be

more difficult to market.

In the face of economic uncertainty, forest landowners

may be encouraged to consider selling off portions of their

lands to developers, or converting them to other more profitable uses. Working forests that are producing a valuable

commodity are less likely to be converted to an alternative

land use. In Washington, conversion from forestry to alternative land uses has been identified as one of the biggest

threats to biodiversity (Washington State Department of

Fish and Wildlife 2005). The loss of private timber lands

jeopardizes our region’s ability to meet society’s growing

demand for wood products (Haynes 2003). While timber

production on private forestlands has remained relatively

stable, there has been a 96 percent reduction in harvest 

on federal lands between 1989 and 2001 (Oregon Forest

Resources Institute 2003). Declines in harvest on federal

lands during this period were related to changes in management priorities associated with needs for endangered

species. 

Although lands managed to maximize profits in the

forest industry may be less than ideal for wildlife, these

lands, nevertheless, have an important function in biodiversity conservation. Recently, conservationists have realized

109

Figure 1—A comparison of management goals relating to public and private forestland ownership (Phillips 2002}.
that a reserve system alone will most likely be insufficient

to sustain all wildlife populations (Wilcove 1989, Hansen

et al. 1991, Lindenmayer and Franklin 2002). Thus, private

lands play an important support role in the conservation

process, and it is important that public agencies carefully

consider the potential negative consequences any new regulations might have on the economic viability of private

timberland owners (Forest and Fish Report 1999).

Differences Between Managed and Unmanaged Forests

What are the principal differences between managed

and unmanaged forests? The biggest differences, in terms

of wildlife habitat, are the degree of structural complexity

present within the stand. Unmanaged forests often contain

a greater diversity of tree sizes, including some that may 

be very old (200 plus years) and very large. Mature forests

often have a multi-layered canopy including a well-developed understory of shrubs and young trees. They typically

contain an abundance of snags and downed logs of all

sizes. In contrast, managed forests typically are younger,

and within any given stand, the trees are more uniform in

height and diameter. Managed forests often lack a significant understory component if they have not been thinned.

Snags typically are scarce, primarily due to worker safety

concerns, and downed wood also may be less abundant. 

Many of the structural differences between managed

and unmanaged forests can be explained by differences in

the frequency and intensity of disturbance in these forest

settings (Hansen et al. 1991, Lindenmayer and Franklin

2002). In unmanaged forests, stand initiation occurs naturally following a catastrophic disturbance such as fire. In

these settings, succession advances rapidly from the herbaceous plant and shrub phase to the seedling tree phase as

shade intolerant conifers become established and begin to

coalesce, and shade out, other shade-intolerant vegetation.

Vertical tree growth continues rapidly until stand canopy

closure occurs as trees reach maturity. If undisturbed, dominant trees in these stands may continue to grow and survive for hundreds of years. Hansen et al. (1991) reported

that the average interval between catastrophic natural disturbances for stands in Mount Rainier National Park was

435 years. During this long succession of growth, withinstand diversity is created by the occurrence of low to intermediate intensity disturbance events such as individual 

tree mortality (e.g., disease, insect infestation, breakage or

wind-throw), geological processes (e.g., slope failures and

landslides), windstorms, or small-scale fires. Within-stand

diversity also is increased by the in-growth of shade tolerant species in the forest understory. Stand development is

essentially the same in managed forests although additional

efforts are made to ensure the initiation of a fully-stocked

stand. However, most of the processes that create withinstand diversity are interrupted by harvest when rotation age

is attained. Thus, the frequency of disturbance in managed

forests (i.e., harvest) occurs at intervals that are determined

by local site conditions, the tree species being grown, and

current market demands. Forest management typically

shortens the duration of the early successional stages that

precede tree canopy closure and eliminates the late successional stages (Franklin and Maser 1988).

In unmanaged forests, the spatial pattern of landscapelevel diversity between stands often is a function of topographic features and how they interact with disturbance

factors such as fire. Historically, fires were fairly prevalent

in the Pacific Northwest, and they create a natural mosaic

of varying stand ages across the landscape (Agee 1993,

Hansen et al. 1991). In contrast, the size and spatial

arrangement of stand age classes in managed forests is a

function of the spatial occurrence and size of harvest activities. The average clearcut size in private timberlands in

Washington is typically less than 60 acres (Washington

Forest Protection Association 2003). Because only a relatively small portion of the overall landscape is harvested

each year (1-4 percent), and because rotation cycles generally are 50 years or more, managed forest landscapes can

be characterized as steady-state shifting mosaics of stand

age classes (Bormann and Likens 1979). Despite these differences, managed forests contribute significantly to

wildlife conservation. Although they may not provide the

entire range of stand conditions present in unmanaged

forests, they occupy a substantial portion of the overall

landscape. In Oregon and Washington there are an estimated 18.4 million acres of privately-owned managed forests

(Washington Forest Protection Association 2003, Oregon

Forest Resources Institute 2003). Managed forests provide

a variety of young to intermediate stand age classes, and

thus, provide considerable habitat diversity for species

adapted to these conditions. Brown (1985) reported that

managed forest stands were capable of supporting an estimated 277 of the 460 vertebrate species believed to occur

in the forests of western Washington and Oregon. Bunnell

et al. (1997) investigated the consequences of forest management on terrestrial forest-dwelling vertebrates and concluded that current forest practices posed no immediate

threat to any of the 300 terrestrial vertebrate species in

Oregon forests.

Although habitat conditions in managed forests 

may be less than optimal for certain wildlife species, they

remain productive areas for species adapted to the conditions that occur in managed forests. Where it has been

shown that management practices negatively impact species

110
or ecological processes, federal and or state regulations

have been created to ensure the protection of public

resources. As our understanding of ecological processes

and species-habitat relationships improves we may identify

further conflicts between management for timber production and wildlife. Thus, it is important that managers seek

creative solutions to reduce or eliminate these potential

problems themselves. If the conflicts cannot be resolved it

is very likely that they may lead to new regulations in the

future. 

Sustaining Biodiversity in Managed Forests

Private timberland owners have a responsibility to

maintain the integrity of the public resources occurring

within their ownership. Aside from their responsibilities as

stewards of the land, it is in their best interest to contribute

where possible to the achievement of biodiversity conservation goals. Within the constraints of timber production

goals, landowners and managers should be continually

striving to identify and improve management practices to

reduce negative impacts on wildlife and their habitats. To

demonstrate their commitment to the public and to show

that they are practicing sustainable forestry, the majority 

of industrial timberland owners have elected to participate

in third-party forestry certification programs such as the

Sustainable Forestry Initiative (SFI) and the Forest

Stewardship Council (FSC) (Hobbs et al. 2002). A major

portion of the principles in SFI and FSC certification standards specifically address biodiversity conservation (Forest

Stewardship Council 2004, Sustainable Forestry Board

2005). Adherence to these standards has stimulated industrial timberland owners to seek out innovative ways to

incorporate biodiversity conservation measures into their

standard operating procedures and to initiate monitoring

activities. Lindenmayer and Franklin (2002) identified four

primary areas where private timberlands can contribute to

biodiversity conservation. These include: 1) supporting

wildlife populations, 2) maintaining the integrity of aquatic

systems, 3) protecting sensitive areas and unique or imperiled fauna and flora, and 4) facilitating the movement of

animals through the landscape (i.e., connectivity).

Because management actions are typically applied at

the stand level, often it is the individual forest stand that

becomes the focal unit when trying to increase habitat

diversity in managed forests. However, ownership size

(total acres), and the distribution of parcels under management (i.e., contiguous or dispersed), ultimately determine

the set of options available to managers for improving spatial habitat diversity (fig. 2). If an ownership is large and

contiguous, opportunities may exist to manipulate the location and timing of harvest units to improve the interspersion of stand ages. However, if ownership is relatively

small, or if it is made up of small, disjunct parcels, there

111

Figure 2—The influence of ownership size and distribution on landowner options for managing forested

lands to enhance biodiversity.
will be few opportunities to improve the spatial diversity 

of forest cover at the landscape scale. Management for biodiversity conservation in mixed ownership situations is

challenging because goals and constraints differ between

owners, and because they are only a part of the overall

landscape neighborhood. There is little that can be done to

improve landscape spatial diversity without the cooperation

of your neighbors. Under this ownership scenario, management efforts should focus on manipulating within-stand

conditions to create greater structural complexity within the

stand. Unfortunately, much of the scientific literature available to guide decision-making at the landscape scale is primarily relevant to large and contiguous ownerships (Hunter

1990, Noss et al. 1997). Although the area managed may

be relatively small, and unlikely to provide all the specific

habitat needs of certain species, that does not mean that the

ownership is not contributing to the welfare of that species.

Small landholdings are just as important to the overall success of biodiversity conservation in the landscape matrix

and their individual roles should be to try to provide whatever habitat features they can in support of the needs of the

population occupying the landscape. 

Managing Within-Stand Structural Diversity 

In even-aged managed forests, within-stand structural

diversity is generally low because trees are relatively homogeneous in composition, size and stature. Thus, structural

diversity can be enhanced by retaining as many individual

structures or legacy features as possible from previous

stands. Individual structures include green recruitment trees

and wildlife reserve trees purposely left behind during 

harvest, standing dead or partially dead trees (i.e. snags),

tall stumps, downed logs and other woody debris. Green

recruitment trees are living trees that will continue to 

grow in diameter during the next rotation. They often are

retained in clusters along waterways or in areas with unstable slope conditions and where they are least likely to

interfere with stand management or harvest operations.

Occasionally individual trees are left scattered throughout

the unit or around groups of snags. Very large diameter

green trees (i.e., legacy trees), retained from the previous

rotation, provide distinctive structural features that are rare

in managed stands and that are especially valuable for 

birds of prey (i.e., nest platforms, roosts, hunting perches).

Wildlife reserve trees are standing, defective trees that

often have large limbs and the structural elements (mistletoe brooms and multiple tops) needed to support nesting

and denning. 

Eventually green trees die and become snags (a standing dead, or partially dead tree), or they are wind-thrown

and become a downed log. Snags and downed logs are

especially important habitats for wildlife nesting and foraging, and they are utilized by a wide variety of species

(Hunter 1990). Johnson and O’Neil (2001) reported 93 

vertebrate species were associated with snags in Pacific

Northwestern forests. Snags also provide essential habitat

requirements for cavity-using species. Between 25 and 30

percent of the vertebrates found in most forest types in the

Pacific Northwest use cavities in snags for reproduction 

or roosting (Bunnell et al. 1999). Snags typically are 

less abundant in forests managed for wood production

(Risenhoover and Murden 2006). This is partially due to

issues associated with retaining snags at time of harvest.

The majority of snags in working forests are considered

safety hazards to workers and must be removed during harvest operations to eliminate potential safety risks to workers (Washington State Department of Labor and Industries

2004). In an attempt to compensate for this snag deficiency,

several industrial forest landowners are experimenting with

different ways of artificially creating snags (Huss et al.

2002, Kroll 2005). However, this research is preliminary,

and it remains uncertain what wildlife species will use 

created snags or how long they persist during the rotation. 

A second means of increasing structural diversity 

in managed forests involves the use of silvicultural prescriptions. Precommercial thinning frequently is applied 

to reduce tree density in young stands (10-15 year old).

Thinning densely stocked young forest stands can encourage shrub regeneration and accelerate the development of

herbaceous ground cover (Muir et al. 2002). Commercial

thinning of mid-rotational age classes can release dominant

trees and encourage the development of understory shrubs

and saplings. Hayes et al. (2003) showed that thinning

increased stand use by certain bird species in western

Oregon. However, thinning in managed forests is not without constraints as the cost of thinning may exceed profits

realized depending on markets and logging cost.

Development of structural diversity within a forest

stand requires planning, knowledge of local site conditions,

and the availability of existing legacy features. The development of inventories of existing structures within stands

can be used to facilitate the development of retention

strategies that minimize the impact to the operation while

maximizing benefits to wildlife. 

112
Maintaining the Integrity of Aquatic Systems 

In the Pacific Northwest, concerns about declining

salmon stocks and water quality have led to new regulations governing forest practices (Knudsen et al. 1999). As a

result, fish-bearing streams in forested areas are now protected by riparian management zones (i.e., strips of forest

adjacent to streams). These riparian management zones act

to buffer streams and to ensure maintenance of important

ecological functions such as water quality, bank stability,

large wood inputs, and nutrient inputs (Naiman and Bilby

1998, Verry et al. 2000). 

Riparian management areas provide other important

functions as well. First, the green trees retained in these

buffers can continue to grow over time and eventually provide mature forest habitat distributed over approximately

10-15 percent of the landscape (Forest and Fish Report

1999). As they continue to grow and develop, these riparian stands eventually will contribute some of the late-successional forest age classes that currently are not available

in managed forests. Second, because the riparian areas will

not be harvested, they provide places for large snags to

develop and to provide for the needs of cavity-dependent

wildlife without risking worker safety. Finally, riparian 

corridors and associated habitats will become the backbone

of basins and will facilitate movements and can provide

connectivity for wildlife throughout the entire watershed

network. Gene flow allowed by this connectivity will help

maintain population viability and sustain biodiversity.

Ecologically Sensitive Sites and Rare or Unique

Habitats 

Some wildlife species are already rare or they have a 

limited distribution on the landscape. Some species have

evolved to have such limited tolerances that they do not

respond well to disturbance or habitat changes associated

with forest practices. The conservation of these species

often requires protection or securing of specific resource

sites, such as nesting areas, or avoiding disturbing them

during critical times of the year (i.e., nesting and brooding). In forest practices these situations are usually dealt

with by setting aside areas and precluding timber harvest,

or restricting forest management activities during certain

times of the year. 

Protecting and maintaining the function of ecologically

sensitive sites such as seeps, springs, caves, talus slopes,

cliffs, and rock outcrops are best accomplished by excluding equipment use in and around these areas and by applying buffers to maintain site integrity. These areas can contain

rare plants and animals, or they may provide unique habitat

features for a variety of wildlife species. Unique and rare

habitats often are important for nesting, roosting, foraging,

and breeding habitats for a large number of wildlife species

(Oregon Natural Heritage Program 2003, Washington State

Department of Natural Resources 2003). Unique and rare

habitats include oak woodlands, aspen stands, natural

meadows, forested and non-forested wetlands, bogs, or

fens. These areas usually are not ideally suited for timber

production. 

Sustaining the Future

Private timberlands are an essential component of 

biodiversity conservation. Despite public perceptions, 

these areas contribute habitat that sustains large numbers 

of wildlife and they are important for “keeping common

species common.” Private forest lands are also playing a

greater role in sustaining harvestable surpluses of many of

the regions big game species which depend on early forest

successional stages for forage. For conservation efforts to

succeed, it is critical that the public, conservationists, and

state and federal agencies gain a greater appreciation of 

the role privately-owned timberlands play in the landscape

they occupy. The goals for the management of privatelyowned forests cannot be to recreate past conditions. Instead

working forests will continue to be places focused on the

production of wood products. However, private lands can

continue to provide productive habitats for a wide variety

of wildlife and help to sustain regional biodiversity.

There have been major improvements in forest management practices over the past several decades that are

promoting sustainable forestry. The current set of regulations governing forest practices in the Pacific Northwest is

designed to protect public resources and to maintain biodiversity while also considering the need to maintain a viable

forest industry. Private timberland owners are in the process

of implementing these new guidelines and are working on

improving their management practices. However, there will

continue to be opportunities for improvement. We need

sound science to guide management decision making. We

need to be continually challenging our assump-tions about

what is good for wildlife and not forget that regulations

often have unintended consequences (Holling and Meefe

1996). Research will be necessary to determine the effectiveness of our current management practices at maintaining biological diversity within managed landscapes. With

additional understanding comes an opportunity to continue

to develop new and creative solutions to further increase

the compatibility of forest management and conservation

efforts. 

113
ACKNOWLEDGMENTS

We wish to thank T. Harrington, J. MacCracken and G.

Nicholas for their reviews and helpful suggestions on an

earlier version of the manuscript.

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Online at http://www.dnr.wa.gov/forestpractices/rules/

forestsandfish.pdf. (Date accessed unknown).

Washington State Department of Natural Resources. 

2003. State of Washington natural heritage plan.

Olympia, WA: Washington Department of Natural

Resources. 64 p.

Washington Forest Protection Association. 2003. Forest 

facts & figures. Olympia, WA: Washington Forest

Protection Association. 16 p.

Wilcove, D.S. 1989. Protecting biodiversity in multiple-use 

lands: lessons from the US Forest Service. Trends in

Ecology and Evolution. 4: 385-388.

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1 Malcolm R. Dick, Jr. is Washington Manager, American Forest Resource Council, 606 Columbia St NW, Suite 104, Olympia, WA 98502.

Managing for Wildlife Haitat in Westside Production Forests

PROACTIVE MANAGEMENT CONSIDERATIONS 

FOR WILDLIFE HABITAT TO ENSURE PROFITABILITY

Malcolm R. Dick, Jr.1

INTRODUCTION

I am a non-scientist and my topic is non-scientific. My

background includes political science, but with knowledge

gleaned from a lifetime associated with forests, forestry

and the issues involved in forest management. My dad’s

forestry career began in 1939 and ended in 1980, spanning

two careers in forest management and forestry education. I

came along in 1945 and by 1950, knew that I wanted to

follow in his footsteps, which I did. It has been a fascinating journey not to be missed.

ABSTRACT

Proactive management of wildlife habitat begins with understanding forestland ownership and the goals of the landowner. There exist five broad classes of forestland owners: industrial, non-industrial, state, federal and tribal. All owners

have different objectives, resulting in different amounts and qualities of habitat. Each landowner class brings its own

wildlife benefits and challenges.

Several principles are suggested to begin the journey for proactive management of wildlife habitat on western

Washington’s forestlands.

• All forestland is managed regardless of the owner or manager.

• Natural resource managers must embrace the art of the possible.

• Asphalt produces little wildlife habitat.

• We must keep our eye on the prize.

• People should be encouraged to own forestland.

• Good science is critical to effective habitat management.

• Landscape planning is a next generation habitat management tool.

The above principles reflect the viewpoint of many land managers. While not complete or the only list that could be

developed it is worthy of examination by all wildlife managers as a window into the minds of the habitat owners or managers.

KEYWORDS: Habitat ownership, diverse landowner goals, habitat management principles.

117

Washington has grown, during my life, from two 

million to over six million people (OFM 2006). The place

where I shot my first deer now has houses on it; my

favorite duck hunting areas are covered with more houses

or freeway. The adjacent dairy farm where a close friend

lived now is a freeway interchange. Thousands upon thousands of acres of forestland have been converted to other

uses, burned, or devastated by epidemic insect and disease

problems, while we argue about mollusks in tiny streams,

perennial stream initiation points and the basal area left in

stream corridors. We are fiddling while Rome burns, my

friends.
My words may annoy some of you. If, however, just

one of you says, “Hmmmm. This guy might have a point,”

I will have achieved my goal of causing you to think about

the road ahead. 

LAND OWNERSHIP AND MANAGEMENT

PHILOSOPHY

A long-time associate of my father, and a darn good

forester, once told me, “Our job (as corporate foresters) is

to make a profit for the company. We are not here to be

‘socially responsible;’ we are not here to provide amenities

other than those required by law. We are here to ensure the

company meets shareholder expectations. Period.”

I did not fully agree with the statement but he had a

point. If a manager governs land in a manner that does not

achieve landowner goals, the company will not survive, the

agency will not survive, and to a degree, the land will not

survive in its current form. It is tempting to lump land on

which trees grow as being the same, managed the same,

producing the same products and amenities. Land ownership is much more complex. One of our first goals, then, 

is to understand landowner objectives and problems land

managers face in achieving their ownership objectives. 

Industrial Forestlands

Industrial forestlands comprise about a fifth of the

total forestland base in Washington (WFPA 2005). Many

people perceive these lands solely are managed to produce

income; forests are clear-cut and then planted, cornrow

style, acre after acre. The perception is only partly true. 

These lands are managed to produce revenue. They

also produce thousands of products society demands and

uses every day. The revenue generation process creates

jobs, pays taxes, maintains open space and creates a

healthy environment while the economy benefits. Industrial

forestland is not ideal for all wildlife species but a wide

range of species can and do make a good living on these

lands. Strict forest practices regulations ensure protection

and maintenance of certain habitat types and high water

quality.

Pressures on these lands are multiple and substantial:

there is pressure to produce products and revenue on an

ever-decreasing productive land base. There is pressure to

convert the lands to other uses, pressure from neighbors

who do not want “their” trees cut, and pressure from those

who think industrial lands have an obligation to produce

amenities these lands may not be able to produce and still

achieve the owners’ goals. More than one landowner has

said, “To heck with it,” and left the region. Those who

remain recognize social responsibilities associated with

forestland management, i.e., “pressures,” but are struggling

to find the ability to meet revenue expectations, while 

concurrently meeting society’s demands. 

Non-industrial Forestlands

Non-industrial forestlands comprise fifteen percent 

of the state’s forestland base (WFPA 2005). Ownership is

characterized by thousands of small parcels, closer to urban

centers, under significant pressure from developers, various

tax burdens, and general urban expansion. Non-industrial

landowners manage their lands for a variety of goals but a

major purpose almost universally is income generation. 

The typical non-industrial landowner fiercely protects

his or her land and gives it up only under duress. We must

keep in mind that much of this land will change hands over

the next generation and the new owners may or may not

live on the land. Landowner education will become

increasingly important. 

This forestland ownership component provides critical

forested wildlife habitat where it is needed most of all. We

should do all in our power to encourage its retention.

Washington State Forestlands

State of Washington forestlands cover more than 2

million acres of Washington, most of which is in western

Washington (WFPA 2005). The lands are held in trust for

specific beneficiaries in a unique fiduciary relationship

between the State and these beneficiaries. Beneficiaries

closely watch revenue production, in the same manner as

corporate shareholders watch their investments. Beneficiar-ies have the ability to divest themselves of these lands

if revenue production falls or management expenses rise 

to unacceptable levels. The Habitat Conservation Plan of 

the Washington State Department of Natural Resources,

among other land management instruments, ensures recognition and protection for a wide variety of fish and wildlife

species.

State trust lands face the same pressures as private

forestlands, and, additionally, are subject to the vagaries of

a state legislature filled with people who, as a body, have

little understanding of resource management.

USDA Forest Service Lands

Non-wilderness lands of the USDA Forest Service

cover an additional quarter of Washington’s forests (WFPA

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2005). Forest Service land managers face their own set of

intense pressures. Let me paraphrase something I wrote

several years ago:

Today’s National Forests are in conflict with themselves. Insects devour vast areas, recreationists 

trample stream banks, shoot each other, overwhelm

sanitation facilities. Each tree scheduled for harvest 

is fought over as if it were the last Douglas fir in 

existence. Roads are poorly maintained due to lack 

of funds and budgets continue to decline. Perhaps

worst of all is the complete, profound inability of

Forest Service professionals to do their job. If they

aren’t stopped by administrative appeals or lawsuits, their own process stops them nearly as fast.

Glaciers move faster.

Forest Service lands are “growing” old growth and

provide significant old-growth habitat but little early-seral

forest habitat. The downside is that with the cessation of

timber harvesting on federal lands, species dependent on

early-seral forest, such as deer, elk, and certain predators

are forced to relocate or perish.

Tribal Forestlands

Tribal lands comprise less than ten percent of the

forested land base. Washington’s Native American reservations are managed by and for tribal interests that range

from revenue production, religious significance, wildlife

habitat management, and food and small products, e.g. 

basket weaving materials, cedar bark, etc.

Wildlife enhancement, particularly for larger species

(deer, elk, and bear) is an important tribal goal on most

reservations. While tribes reserve the right to manage their

lands for their own goals, the wildlife benefits of such

management should not be overlooked. 

So there you have it: five landowner groups provide

distinctly different habitat types and habitat management

opportunities in different locations in western Washington,

and the entire state, for that matter. Each brings its strengths

and weaknesses but the land base exists for diverse habitat

management opportunities.

PROACTIVE MANAGEMENT ACTIONS

The bulk of this meeting has been spent discussing

technical aspects of wildlife habitat management. I would

like to explore social, economic and political aspects of the

issues involved in habitat management on Washington’s

forestlands through several principles that could lead

resource managers, including wildlife habitat managers, to

be more effective.

All Forestland Managed

All forestland is managed, regardless of the owner 

or manager. The time of Lewis and Clark is past. That

includes wilderness and National Parks. Every acre in this

country is under guidance from a body that decides what

does or does not happen on that acre. 

The idea that we can, or even should, recreate vast

stretches of untrammeled wild lands is archaic. We natural

resource managers now are in the business of managing

lands and all the critters and plants that call them home.

The sooner we embrace this concept, the sooner we can

concentrate on holistic wildlife habitat management on

today’s land base for tomorrow’s citizens. 

Embrace the Possible

We must embrace the art of the possible. Most species

will make the transition from 1806 to 2006. Some will not.

The northern spotted owl (Strix occidentalis), for instance,

will not survive in much of its range. The barred owl (Strix

varia) out competes it in almost every category of life.

Charles Darwin wins this round. 

Spending copious amounts of time, money and energy

on saving species that cannot be saved is an exercise in

futility. At some point, we must recognize and accept the

inevitable ascent or descent of any given species, as it

copes with life, including human occupation or use of its

habitat.

A companion issue is the federal Endangered Species

Act (ESA), which discourages wildlife habitat creation or

enhancement in working forests. Landowners are punished

for having certain wildlife habitat via severe land use

restrictions. We must reward landowners for creation and

enhancement of critical wildlife habitats. ESA revisions

that embrace such changes will better protect landowners

and wildlife.

Asphalt and Wildlife

Asphalt supports little wildlife. We all need to work at

keeping forestlands growing trees versus strip malls, subdivisions, etc., where possible. Concurrently, we must accept

that not every forested acre will survive as forested habitat. 

Each forested acre need not – cannot – provide habitat

for all creatures. All forestlands contribute to wildlife habitat. A deer, bear or neo-tropical migrating bird, for example, could not care less if trees grow in rows as long as he

119
or she can eat, sleep and procreate. It is important that we

assess how each land ownership class fits into the big picture and how these lands can contribute to overall wildlife

needs, while meeting the landowners’ or managers’ goals. 

Keep Our Eyes on the Prize

We must keep our eyes on the prize. We waste substantial energy analyzing trivia. The angst created by

attempts to determine at what point stream flow begins, 

for example, and endless arguments over what diameter of

trees to harvest on federal lands, lawsuits, appeals and crippling process all detract from the land manager’s ability to

manage the land. This happens as we watch thousands of

acres of forest disappear from fire, land conversion, insects

and disease. Keep in mind when the land manager’s time,

energy and resources are soaked up with trivia, important

stuff does not get done.

Forestlands Incentives

There should exist incentives to own forestland.

Forestland owners can accrue significant net worth in

forestlands, including, but not limited to lands suitable for

development. Various proposals to modify estate tax standards invariably stall in Congress. That is a tragedy for

wildlife; here is why:

A local family recently was forced to sell two substantial parcels of managed forestland to pay a deceased family

member’s estate tax. Those forests were habitat in an area

that needs forested habitat. The now former habitat will

host houses, not by choice but by need. This is but one

example of a problem that is more common than you might

think. We need a new paradigm on how we approach keeping forestland growing trees and habitat. 

Good Science as a Wildlife Management Solution

Good science is a critical piece of the wildlife management solution. You undoubtedly are aware of the controversy over an Oregon State University study that made certain

conclusions about the impacts of timber salvage on conifer

regeneration on federal land. Study results were plausible

but methodology was suspect. That the study was rushed

into the public’s eye, with inadequate review did not help.

Everyone associated with the study got a black eye, regardless of the study’s ultimate fate.

Natural resource managers need credible science 

produced by qualified scientists. There are many forms of

science and many levels of qualifications. We must define

“credible science,” different levels of science, different

types of science and the qualifications of those we call,

“scientists.” This is a festering issue that must be resolved

sooner rather than later. The credibility of all resource 

managers and natural resource scientists is on the line.

The Next Generation

Finally, landscape planning is a key next generation

wildlife management tool. Wildlife habitat is both temporal

and spatial, ever changing over time and space. The ESA

has driven us into a corner in which we increasingly manage for single species on discrete pieces of real estate.

Until we look at the landscape as a whole, and wildlife as a

complex assortment of creatures, we will have missed an

important element in our responsibilities as natural

resource managers. 

SUMMARY

The easy part of any job is enumerating problems and

potential solutions as I have done above. It is much harder

to actually do something about it, but as Confucius is

reputed to have said 2500 years ago: “The journey of a

thousand miles begins with the first step.”

The issues discussed represent the thoughts of a significant number of people who control and manage forested

habitat. As such, my list is worth your perusal, regardless if

you agree with the issues involved. 

Perhaps the next step in this thousand-mile journey is

to agree on a common set of problems we need to solve in

our quest to manage land to produce products and revenue

and jobs, plus a variety of wildlife. We have begun that

journey with today’s conversations.

LITERATURE CITED

Washington State Office of Financial Management 

Population Statistics [OFM]. 2006. Current and historical data sections. Olympia, WA: Access

Washington State and Government Official Web Site.

http://www.ofm.wa.gov/pop/coseries/default.asp 

(Accessed 20 July 2006).

Washington Forest Protection Association [WFPA]. 

2005. Forest facts and figures. Olympia, WA:

Washington Forest Protection Association. 13 p.

http://www.wfpa.org/pages/brochure.html (Accessed

20 July 2006).

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WORKSHOP

SYNTHESIS
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1 Pete Holmberg is Manager for Silviculture and Regeneration, Land Management Division, Washington State Department of Natural Resources, 

1111 Washington St SE, Olympia, WA 98504.

Managing for Wildlife Haitat in Westside Production Forests

MANAGING FOR WILDLIFE HABITAT IN WESTSIDE 

PRODUCTION FORESTS: A WORKSHOP SYNTHESIS

Pete Holmberg1

INTRODUCTION

The purpose of this paper is to bring out and integrate

workshop themes with other relevant research and to synthesize these into potential solutions where apparent shortfalls exist. The paper’s scope is defined accordingly. Thus,

I will first summarize the major points of scientific knowledge brought out at the workshop and integrate other relevant scientific knowledge. I will then synthesize the

combined body of knowledge, highlighting apparent voids

which I will attempt to fill with some observations and

ABSTRACT

Two major themes emerged from workshop presentations regarding combining wildlife habitat and revenue objectives

in Westside production forests. The first theme was that a substantial, albeit fragmented, base of multi-disciplinary knowledge exists, as was clearly displayed at the workshop. This knowledge base could serve foresters well in managing for combined revenue and wildlife habitat objectives in Westside production forestry. On the other hand, the significant knowledge

base is partly counter-balanced by notable difficulties, including social credibility of the forestry profession and regulatory

responsibilities for ecosystems that are without central governmental focus. The workshop’s second major theme was a

diminishing profit potential for forest landowners exacerbated by environmental law and rule enforcement that can be counterproductive. This contributes to Westside forest land conversion, particularly urbanization and real estate development.

Thus, land use conversion is thought to pose possibly the single greatest threat to general wildlife habitat. Habitat creation

and management efforts will not be relevant if they do not include plans to reverse forest land conversion. To achieve this, 

a system based on incentives is suggested. 

The first theme poses the question why foresters still seem to have problems credibly managing for multiple objectives

when substantial interdisciplinary knowledge exists and is generally available. I suggest a method to synthesize complex

arrays of scientific knowledge into a logical decision format. The decision format is for execution of activities in the present

to achieve long-term, large-area multiple objectives. A silvicultural system is suggested to deliberately manage stand cohorts

that correspond to objectives while recognizing their silvics. A key to this is to correlate landscape, stand-rotation, and

stand-activity objectives and take advantage of site-specific characteristics. This system will increase transparency of 

decisions for the public, which should help build a constructive dialog between the public and land managers.

KEYWORDS: Silviculture, wildlife, prescription, cohort, multiple objectives, financial analysis.

123

suggestions. Specifically, I will offer some thoughts regarding the need for a deliberate methodology in establishing

clear, structured objectives at stand-activity, stand-rotational, and landscape-perpetual scales and in linking 

planning and execution.

WORKSHOP PRESENTATIONS

General

There were two major themes at the workshop. The

first and by far most prevalent of these addressed the science,
techniques, and field craft to manage forests for multiple

wildlife habitat and financial objectives. The second theme,

mentioned by several speakers and possibly the most fundamental to sustainability of forested wildlife habitat, concerned the unintended consequence of environmental laws

and rules that contribute to accelerated conversion of forest

lands to more lucrative uses. 

Keynote Address: How We Got to Where We are Today

Perceptions of the role of managed forests as wildlife

habitat are changing (Aubry 2007). A historical review of

the last one hundred years shows a repeating pattern of

progress in which solutions are devised, and after some

decades of increasing disregard they are rediscovered with

a new twist. Thus, in the early 1900s, Theodore Roosevelt

established the doctrine of “wise use” of natural resources.

Wise use implied, as a public trust, using science to ensure

a balance between resource extraction and replenishment.

Later, in the 1930s Aldo Leopold initiated wildlife habitat

management in the United States by advocating scientific

solutions to increase carrying capacity for game species

and later for all vertebrates and associated niches. Over

time, key turning points in thinking about wildlife management crystallized. In 1979, Jack Ward Thomas precipitated

a public realization of the importance of managing forest

biodiversity on spatial scales. In 1987, Jerry Franklin and

others presented the idea of landscape ecology and planning. A couple of years earlier, in 1985, the idea of extending protection to entire riparian systems, including

headwaters, began and gradually took hold through the

1990s. Concurrently, beginning in the early 1980s, old

growth forests began to be recognized as possibly unique

habitats for key wildlife guilds. Jerry Franklin and others

introduced the idea of “new forestry” as “kinder and gentler” forestry that would better accommodate ecological 

values than tree farm forestry while allowing for the

extraction of commodities. This idea gave rise to managing

for late-seral habitat including previously unrecognized

stand cohorts such as snags, green multi-rotational trees, and

coarse woody debris. In other words, we have rediscovered

silviculture as the tool to achieve multiple objectives in

managed forests! This involves managing at multiple—

harvest unit, landscape, and micro-site—scales. The last

turn in the path of progress is the emergent realization that

old growth and the landscape scale may not be as important for most species of wildlife as initial hypotheses indicated. Never-theless, some species, the northern spotted

owl (Strix occidentalis caurina) in particular, depend on

old-growth landscapes. 

Synopsis of Presentations 

There are many positive trends in wildlife habitat management. Although nascent knowledge tends by nature to

be compartmentalized, there is an over-riding trend towards

inter-disciplinary communication and knowledge integration. This is evidenced through an emerging core of interdisciplinary scientific consensus. Scientific disciplines that

interact with forestry (wildlife, ecology, etc.) acknowledge

that silvicultural manipulation is a preferable, if not the

only, practical option for deliberate and accelerated recovery of otherwise rapidly vanishing niche structures essential for key wildlife guilds. Silviculturists are devising

regimes and landscape approaches that accommodate,

indeed are often based on, scientifically derived arrays of

discrete and measurable stand parameters that describe key

wildlife habitats. Yet, there is an apparent reluctance to

apply this knowledge towards actual results on the ground

in managing for both wildlife and revenue objectives in a

highly competitive world market, a market that puts our

forests at risk of land-use conversion. 

Integration of Multiple Disciplines into Silvicultural

Solutions at the Stand Level to Enhance Structural

Elements

There is advocacy by wildlife scientists for accelerating habitat development through silvicultural means (Hagar

2007). In particular, there is interest in promoting thinning

techniques that create variable densities, develop more than

one canopy, and nurture stand cohorts such as large down

woody debris (LDWD), snags, wildlife trees, and hardwoods whose seeds are forage for the predator food base,

indeed for a variety of species.

Furthermore, scientists are combining inter-disciplinary research findings into silvicultural techniques and

field craft to design regimes that incorporate wildlife habitat objectives (Harrington and Tappeiner 2007). This is

done by both leaving key older stand cohorts at final harvest of the present stand, as well as by selecting regimes 

for the new stand that nurture habitat along with financial

revenue. These approaches, tailored to site productivity 

and developed through growth and yield modeling, are

used to compare and analyze regime alternatives for multiple objectives, such as a specific wildlife habitat as well as

probable future revenue. Rigorous financial analysis can

portray alternatives of both rotational investment value as

well as cash-flow alternatives. The outcome is the ability 

to develop and select the regime that best addresses both

wildlife and financial objectives.

124
Silviculture at the Landscape Level

We are entering a new era of silviculture practice in

which refined stand analysis techniques will be incorporated with management at the landscape level (Brodie et al.

2007). Landscape management is crucial in that it addresses issues (such as wildlife habitat) at the multi-stand scale

where cumulative effects for the particular issue can be

addressed. This approach resolves a wide interdisciplinary

area of contention created by the outdated, but too often

prevalent notion among traditional foresters that issues are

mainly resolvable within forest stands or harvest units. 

Landscape analysis is a hierarchical approach in which

stands attaining certain conditions become the building

blocks to address the particular issue for which the landscape was designated. By using habitat needs of the northern spotted owl as a keystone species (i.e., its stand and

landscape habitat requirements encompass or exceed those

of other species),2 scientists are able to simulate regimes

that integrate equitable revenue generation with accelerated

development of quality habitat first at the stand level, and

then through time retaining a desired proportion of the

landscape in the desired stand condition. Although timevalue-of-money analyses suggest a positive revenue flow,

there is recognition of a tangible reduction in revenue as 

a price for providing ecosystem services.

Opportunity Cost of Managing for Wildlife

More specifically as to risk and market competitiveness, there is a body of research addressing vital economic

nuances that are hidden if one restricts consideration to

broader averages (Latta and Montgomery 2007). This body

of statistical knowledge indicates that viability, indeed 

economic survival, of forest landowners is largely related

to opportunity cost (i.e., the unrealized benefit, or cost, of

adopting a less profitable alternative as compared to another, more profitable alternative) of sub-optimal financial

practices. Thus, growth and yield stand modeling combined

with financial analyses indicate a 50 percent reduction in

value when comparing longer wildlife habitat regimes with

short and revenue-oriented rotations, although both types

of regimes generally have positive investment values.

Notably, the research also indicates a 20 percent increase 

in value of longer wildlife habitat regimes that optimize the

dual attainment of specific habitat conditions with financial

revenue as compared to non-optimal regimes. In other

words, the significant opportunity cost associated with

incorporation of wildlife habitat objectives indicates a

strong need for optimization in selecting and executing

regimes.

Proactive Forest Management for Disparate 

Socio-Political and Economic Demands

There is common but not yet universal recognition that

forests must be managed in accordance with standard principles to be socially viable (Dick 2007). Some of these

principles are: forest management objectives that are well

thought out and balanced against each other, doing essentials first and well (as contrasted with being distracted by

trivia); social recognition that economics largely determine

whether or not forestlands will remain as such or be converted to urban uses; reliance on objective science versus

politically or popularly motivated agendas portrayed as

science; and landscape management of ecosystems. The

hub of these principles, without which other principles are

arguably moot, is to retain current forestland as forest. To

that end, some environmental laws and rules are counterproductive in that they have the unintended consequence 

of contributing to forestland use conversion into more profitable real estate development. Thus the mantra, “asphalt

makes poor wildlife habitat.” Recognizing the need for

environmental protection laws, an enforcement system

based on incentives may be a viable alternative to the 

current approaches which are often financially punitive.

Managing Non-Industrial Private Forest Land 

for Wildlife

The major workshop theme of financially feasible

forest management for wildlife habitat was explored from

the socio-political aspect by several speakers. Specifically,

several presentations focused on the significant portion of

the forest land base in western Washington that is made up

of non-industrial private forests (NIPF) and larger private 

forest businesses. 

The following statistics put the issue into perspective

(Bottorff 2007): 

• NIPF accounts for 19 percent or 2.6 million acres 

of forestland in Washington, most of which is highly

productive (generally western Washington) and often

managed for both “wildlife” and timber.

• NIPF at present accounts for 30 percent of timber 

volume harvested in Washington.

• The average size of an NIPF holding is just under 

40 acres.

• Over one-half of NIPF owners are older than 55 

years.

This data strongly implies that wildlife habitat managed on a landscape level is generally not a consideration

for the portion of western Washington forestland in NIPF

125

2 Although applicability of the concept of keystone species may be limited (Aubry 2007, Thomas and Bunnell 2002), it is useful in the context cited.
holdings. However, the ability to sustain species that are

currently not threatened is considered substantial but may

be in jeopardy with continued land use conversion. Notably, NIPF wildlife management amounts to actions that

benefit the most species if not necessarily those currently

most threatened. Although they are necessarily limited to

stand level management, beneficial actions that were 

suggested include:

• Retention, distribution, and creation of snags and

wildlife trees.

• Retention or creation of coarse woody debris.

• Promotion of certain species of understory vegetation,

especially mast-producing trees and shrubs.

• Forage seeding.

• Variable density thinning.

• Hydrologic restoration.

The implication of forest landowner demographics is

clear. The average forest landowner is of retirement age

and may need the proceeds from land use conversion to

finance retirement plans. This further implies accelerating

dissipation of an already fragmented land base. Additionally, marginalization of this significant contributor to the

lumber market will likely increase pressures for higher 

production rates—i.e., lower tolerance for creating wildlife

habitat—on the remaining forestland base. 

Riparian Forest Restoration on Private Forest Land

There is a body of statistical indicators that suggest

significant and unnecessary financial penalties to NIPF

landowners under current riparian rules (Lippke et al.

2007). While it is obvious that early old-growth harvests 

in the lowlands resulted in serious ecological regression in

many riparian habitats, there are also abundant indicators

that correctly applied silvicultural science, techniques, and

field craft are the fastest way to restore riparian forest 

habitats to functional levels. Non-industrial private forest

landowners have until recently, through a series of thinnings modeled on biodiversity pathways, been able to

accelerate the long road back to desired old-forest structure

in riparian zones while protecting short-term riparian function and maintaining a modest economic return. However,

recent adoption of expanded stream classification rules

have caused a 143 percent increase in the area requiring

protection (i.e., the area in which silvicultural intervention

and harvest is largely precluded) on NIPF lands and a 133

percent increase on industrial forestlands. In terms of soil

expectation value, calculated financial decrements from

expanded, and conceivably sub-optimal, riparian protection

range from 22 to 54 percent. Thus, financial impacts of new

rules raise serious questions as to the continued economic

viability of forestland in private ownership. Mean-while,

young even-aged stands subjected to new riparian rules are

unlikely to attain late seral conditions without the nowprecluded silvicultural intervention. 

Forest Landowners Managing for Multiple Objectives

Private forestlands have a disproportionately important

role in sustaining wildlife habitat and biodiversity conservation (Risenhoover and Murden 2007). The problem of

sustaining an adequate forestland base for these purposes

must be assessed against the vital issue forestland owners

face in being competitive in a world-wide market place for

timber. The scope of factors to consider in devising realistic solutions is comprehensive: 

• Worldwide timber market competition constrains 

previously common profit margins.

• Forestland owners are, by and large, committed to

long-term good stewardship but may lack sophistication in devising financially equitable solutions 

to effectively balance multiple objectives.

• There are limits to types of habitat that intensively

managed forests can economically accommodate.

• There are guiding principles that can be used to 

devise financially equitable solutions:

¡ Enhance existing stand structural diversity.

¡ Maintain integrity of aquatic systems.

¡ Recognize and protect ecologically sensitive 

sites and rare or unique habitats.

¡ Keep common species common.

Thus, pertinent extension and education services are

vital in helping forest ownership to be a financially desirable pursuit and thereby conserving the forestland base. 

Ecosystem Management

Integration of all pertinent eco-functions, rather than

compartmentalized approaches, is vital in managing forests

(Kimmins 2007). This mandate is sharpened through demographic trends and inevitably increasing social pressures.

Forestry should perhaps therefore be redefined as “the art

(skill), practice, science, and business of managing forest

stands and landscapes to sustain an ecologically possible

and socially desirable balance of values over appropriate

spatial and time scales.” New responsibilities of the

forestry profession are (1) to change the way in which a

forest is managed as the desired balance of values and

environmental services (the forest provides) and (2) to

reject current practices and resist proposed new practices

that are inconsistent with the ecology and sociology of the

desired values and services over ecologically appropriate

temporal and spatial scales. A fundamental recognition is

that our forests have developed as ecosystems driven by

126
disturbance on grand spatial and sporadic, perhaps climatedriven, temporal scales. In modern times, human society—

its values, needs, and desires, whether related to factual

information or not and wittingly or not—is increasingly

asserting its influence on ecosystems and their management. The forester’s responsibility is to intercede on the

side of science and reason to safeguard social, economic,

and ecological sustainability of forest ecosystems. This

process involves establishing balanced long-term objectives

for all values associated with the forest while also communicating with stakeholders to establish social credibility and

be knowledgeable of markets. A universal trap to avoid is

to view the forest in stasis, as stable snapshots frozen in

time. The alternative concept of “ecological theater” is suggested. In this concept there is a central understanding that

a forest ecosystem is akin to a slow-moving theater or

movie in which change is continual. However, the theater

adheres to a script, i.e., ecological limitations and drivers,

and output varies with manipulation or stochastic occurrences. The social authorizing environment coupled with

market drivers are potentially fatal stumbling blocks to the

whole concept of ecological management if decisions are

not made with appropriate ecological limitations and 

drivers in mind.

OTHER RELEVANT INFORMATION

Unintended Consequence of Environmental 

Legislation: Reduction of Forestland Base

A recent Denman Forestry Issues Lecture at the

University of Washington comprehensively addressed

underlying reasons for the dramatic conversion of forestland to urban uses over the last several decades in the Puget

Sound basin (College of Forest Resources, University of

Washington 2005). Contributing to land-use change, i.e.,

real estate development and urbanization, are rules for

environmental and forest practices that are financially punitive in nature. The resulting high costs and risks associated

with maintaining land as working forests contribute to forest owner’s pursuit of land-use change. Society needs to

effectively address the connection of regulation to land use

conversion, and the consequent impacts on wildlife habitat.

Classical Silviculture 

Classical silvicultural system categories, such as

clearcut, seed tree, and shelterwood (nomenclature that also

describes final harvest systems), may be useful as theoretical points of reference. However, the over-riding principle

of ecosystem management compels site-specific stand

objectives to govern the rotational prescription in accordance with silvical and ecological factors rather than forcing it into stale and old silviculture dogma (Weetman 1996,

Kimmins 2007). The case is magnified when integrating

wildlife habitat with revenue objectives into high-production Westside forests. Specifically, designing site-specific

innovative activities beyond rote repetition of standardized

techniques is the current direction for field forestry.

Cohort Management and Associated Silvicultural

Harvest Techniques in Managing for Revenue and

Wildlife

The advent of new forestry (Swanson and Franklin

1992) and biodiversity pathways (Carey 2003a) set the

stage for using silvicultural techniques to effectively produce habitat along with revenue. To do this, techniques for

thinning and final harvest must represent the best possible

methods to attain the stand-rotation objectives. 

A foundational concept is that different objectives 

rely on different key cohorts.3 Keying on cohorts may be

thought of as a new silvicultural system based more on

intent for future conditions than a snapshot that reflects

transient appearance. Stand cohorts disregarded in singleobjective classical forestry, and some of which only materialize after a long period of time (wildlife trees, snags,

LDWD, and mast-producing hardwoods), have vital importance for wildlife such as the northern spotted owl. By

managing these as well as commercial cohorts, wildlife

habitat may be created along with revenue. Simulations

clearly show that retaining these multi-rotational cohorts at

final harvest significantly accelerates attainment of habitat

for the new rotation. By retaining or creating these cohorts,

risks associated with low stand vigor, such as insect and

disease epidemics as well as to some extent, blow-down, 

are largely bypassed (WDNR 2004).

Two silvicultural techniques specifically combine to

support a silvicultural system of cohort management and

address creation of wildlife habitat: a final harvest system

referred to as “variable retention harvest” (Franklin et al.

1997) and a thinning treatment referred to as “variable 

density thinning” (Carey 2003b, Harrington et al. 2005). 

As emphasized in the sustained harvest calculation of

Washington State Department of Natural Resources

(WDNR), older stand cohorts are deliberately left as a 

part of a variable retention harvest in order to expedite the

stand’s development into functional habitat (WDNR 2004).

127

3 A cohort is a group of individuals or vital statistics about them having a statistical factor in common, such as (but not restricted to) age class

(Helms 1998). 
These cohorts are later deliberately replenished in conjunction with variable density thinnings in the new stand. Thus,

final harvest of previous stands is the first step to create

habitat in new stands. 

Variable retention harvest removes commercial cohorts

but leaves cohorts (or groves of cohorts) that cannot be

quickly recreated and are needed for habitat. Routinely,

these cohorts consist of a few wildlife trees, snags, LDWD,

and mast-producing hardwoods per acre. Retained cohorts

may be clumped into refugia (small groves), either to protect leave trees or to expedite restoration of eco-function.

Variable density thinning has different descriptions,

but all enhance habitat. Both the “skips and gaps” approach

(Harrington et al. 2005) and the approach using mosaics

modeled after structurally complex forest stands (Carey

2003b) deliberately foster openings and unthinned areas

while variable thinning covers most of the area. These

related techniques afford the opportunity to retain closer

spacing around shade tolerant cohorts, widen it around

shade intolerant cohorts, comply with state safety rules by

not thinning around snags, and allow the logger sufficient

landing space and some boost in revenue by harvesting

occasional openings as well as being allowed to forego

some hard-to-reach areas. Variation is implemented on a

scale of approximately 0.5 to 5 acres. Outside of skips and

gaps, relative density (RD) is varied 10 to 15 points (Curtis

1982). Often in two-species stands, variability in RD can

be attained by thinning to a constant stand basal area but

varying leave-tree preferences between, for example, western hemlock and Douglas-fir due to propensity 

of small-diameter western hemlock (Tsuga heterophylla 

(Raf.) Sarg.) and relatively larger-diameter Douglas-fir

(Pseudotsuga menziesii (Mirb.) Franco. var. menziesii), 

as alluded to in figure 1.

The mast-producing hardwoods, vine maple (Acer 

circinatum Pursh) and bigleaf maple (Acer macrophyllum

Pursh), do not have to be felled, yarded, and disposed of 

in many cases. Release of crop trees and enhanced revenue

are feasible with this kind of thinning. Washington State

Department of Natural Resources uses the illustration in

figure 1 in its internal training manual for thinning to illustrate a side- and overhead-view of a stand after variable

density thinning (Holmberg et al. 2006).

SYNTHESIS

General

In view of presentations at the workshop and other 

relevant information, it would appear that sufficient scientific information exists to manage for both revenue and

wildlife habitat objectives in Westside production forests.

Nevertheless, there is a common hesitancy to do so.

Doubtless, some of this trepidation has to do with sailing

uncharted investment waters; concerns most likely also

relate to being overwhelmed by the material to be mastered

and the idea of reconciling objectives that may seem contradictory to each other. I will attempt to demonstrate how

this confounding complexity may be organized in order to

design optimal silvicultural treatments in the present that

steer stand development towards stand-rotational and landscape objectives. A fundamental realization that should

motivate execution to rise above generalities of long-term,

large-area plans is that execution, as contrasted to paper

plans, is irreversible. A quest for state-of-the-art professional performance is therefore to use site-specific characteristics and possibilities to full advantage.

Site-Specific Silvicultural Application 

First, there are a number of foundational concepts to

consider when designing site-specific silvicultural treatments with multiple objectives to be executed in the 

present. They are:

1. Planning intent—a primary influence of strategic 

and other large-area, long-term planning in designing 

a silvicultural treatment for a stand is the strategically

desired, general end state at the stand level.

2. Objectives at landscape, stand-rotational, and standactivity levels—landscape objectives are best

expressed as a proportion of the landscape to be in 

a specified stand condition (habitat quality, merchantable value, etc.) at any one point in time; standrotational objectives attain that same specified stand

condition for individual stands, and each objective is

defined by an array of discrete and measurable threshold targets. Stand-activity objectives are immediate

stand conditions achieved by activities.

3. Threshold targets—objectives are defined by arrays 

of discrete and measurable threshold parameters

referred to as threshold targets (e.g.; for a habitat

objective, threshold targets might be quadratic mean

diameter, dominant tree height, level of competition 

in the stand, trees per acre, number of snags per acre

of a certain minimum size, LDWD per acre, etc.; and

for a revenue objective of maximizing net economic

benefit, threshold targets might be a minimum investment return per acre, a maximum investment

allowance per acre over the rotation, etc.).

4. Linking objectives—objectives at the landscape, 

stand-rotation, and stand activity level must be demonstrably linked, so that an activity can be clearly shown

128
to be the best option for redirecting stand development

towards stand-rotational and landscape objectives.

5. What a landscape is—a useful definition of landscape is an area whose extent and shape is defined by

a particular issue, e.g., visual landscape: an area as

seen from a travel route or vantage point; northern

spotted owl landscape: an area on which nesting pairs

and their juvenile offspring depend for survival and

proliferation (nesting areas plus a surrounding 

territory for roosting and foraging).

6. Why we consider landscapes—we consider landscapes because we need to reconcile the requirements imposed by the issues they represent, and 

these issues are resolvable only at the scales that

define them. 

7. Refining an activity prescription through use of 

products of planning—the products of long-term,

large-area planning useful in guiding site-specific

activities are rotation age, generally acceptable techniques, and likelihood of financial equity; foresters

should understand how these planning products 

were developed and thus be able to justify their 

application or modification at the site-specific level. 

8. Managing objective-driven stand cohorts—wildlife

habitat depends on forest stand cohorts such as 

snags, wildlife trees, and LDWD which are managed on a multi- or non-rotational basis; meanwhile,

129

Figure 1—Example of a variable density thinning. In the side view (upper image), there are different densities between the left and right

sides of the stand, some suppressed understory and mast-producing trees are deliberately retained as are some logs, a thicket is left around

the snag, the two larger wildlife trees at each margin have been converted to snags, and sufficient landing space–a stand opening–is indicated by the log deck. Furthermore, natural regeneration is evident in openings that, if tended in future entries, will produce a scattered

lower canopy. In the overhead view (lower image), two relative densities (RD; Curtis 1982) are indicated for a majority of the stand.

Openings and thickets together constitute around 15 percent of the stand area. Variations in RD of 10 to 15 points and openings and thickets should generally occur on a scale of 0.5 to 5 acres.
commercial cohorts are generally managed on a rotational basis; when modeling commercial stands, noncommercial cohort volume must be subtracted from

predicted volumes, usually as a function of the area

they occupy.

9. Utilization of silvicultural techniques adapted to 

attain site-specific objectives—these include primarily species mixtures and densities in planting 

and thinning, micro-site preparation and vegetation

management, variable density thinning, and variable

density final harvest.

An Illustrative Example

To illustrate how these concepts might be applied, 

let us imagine a fairly typical category of intensively 

managed forestland west of the Cascades: a forest stand 

in the western hemlock-western swordfern (Polystichum

munitum (Kaulf.) Presl.) plant association group. The plant

association group implies a high productivity site, average

50-year site index of 127 ft, and a high potential for

salmonberry (Rubus spectabilis Pursh) in openings, if at 

all present under a forest canopy. 

Let us assume the owner of our common but imaginary stand has recently adopted a landscape objective to

sustain sub-mature habitat for the northern spotted owl

over at least 50 percent of the landscape. The landowner

has additional landscape objectives to maximize annual

harvest from the local block as well as to maximize revenue from the same block, but both must first be consistent

with constraints imposed by the first objective. 

The landowner’s harvest schedule indicates a final 

harvest is due for the particular stand we are now looking

at. This poses the questions for current and near-current

activities: how should the stand be harvested, and how

should it be reforested to best attain stand-rotation objectives? For our particular stand, the landscape objectives in

the previous paragraph translate into stand-rotation objectives for the new stand (1) to attain sub-mature habitat and

sustain it for a period yet to be determined, (2) to maximize stand volume and or value over time, (3) to maximize

net revenue, and implied but not stated, (4) to sustain forest

health. 

The average rotation age required to sustain submature habitat over 50 percent of the landscape may be

approximated by first determining the time it takes for the

stand to enter the habitat window, i.e., when all threshold

targets for sub-mature habitat are met. Threshold targets for

sub-mature habitat are listed in table 1. Stand modeling

indicates that if LDWD, snags, and snag candidates

(wildlife trees) are left in sufficient numbers at final harvest of the current stand, the new stand will enter the habitat condition window at a stand age of 35 years for this

specific site. Rotation age that is consistent with all stand

objectives can now be estimated, sufficient for financial

analysis, through the formula:

Rotation age = Stand age when entering

the habitat window ÷ Proportion of the

landscape that may at any one time not

be in the specific habitat that is targeted

In our example, rotation age = 35 ÷ (100% - 50%) =

70 years. Let us suppose we discovered scattered

salmonberry under the present stand canopy. The plant

association group indicates this presence will develop into

a competitive brush sere when exposed to direct sunlight

soon after final harvest. Thus, there is a need to control the

salmonberry to ensure survival of planted conifer seedlings.

130

Table 1—Stand-rotation objectives and their threshold targets 

• Attain sub-mature habitat for the northern spotted owl:

¡ A canopy composed of trees of the dominant, co-dominant, and intermediate 

crown classes of which at least 30 percent are conifer species

¡ A relative density (Curtis 1982) of at least 50 for trees 4 inches diameter at 

breast height (DBH) and larger

¡ Tree density of between 115 and 270 trees per acre for trees 4 inches DBH and larger

¡ Dominant and co-dominant trees at least 85 feet in height

¡ At least 3 snags or cavity trees per acre at least 20 inches DBH

¡ At least 5 percent of the ground covered with large down woody debris

• Maximize net revenue, as consistent with other objectives:

¡ A bare land value for the rotation of at least $0 per acre at a discount rate of 4 percent

¡ A maximum investment for the rotation of a cumulative sum of $500 per acre
Although the climax sere for this plant association is dominated by western hemlock, Douglas-fir and western redcedar (Thuja plicata Donn ex D. Don) are also well-suited.

In addition, Briggs (1999) found that Douglas-fir planted at

12-ft spacing will produce knots of 1.5 inches and smaller,

indicating #2 sawlogs or better quality in time. 

We now have sufficient information to test silvicultural

activity prescriptions for final harvesting the present stand

and reforesting the new. 

The final harvest activity prescription to test is for a

variable retention harvest in which the requisite snags, snag

candidates (wildlife trees), and LDWD are left as legacies

in small groves. In addition to the eight required standing

snags and trees, we leave an additional four large live trees

per acre to account for progression from standing live, to

snag, to LDWD. The test for this activity prescription is

fairly simple: will fewer leave-tree schemes lengthen or

shorten the period before return on silvicultural investments? The answer is certain to be that it is best from a

financial investment standpoint to provide sufficient legacies and thereby ensure the shortest possible rotation. In

this case, we made a subjective judgment that 12 legacies

per acre would be prudent.

The reforestation activity prescription to test is to plant

a mixture of seedling stock types of 1+1 for Douglas-fir,

plug+1 for western hemlock, and a lesser cohort of plug+1

for western redcedar after a ground herbicide site preparation treatment (lesser brush and slash concentrations will

be spared as browse protected planting spots for western

redcedar). The Douglas-fir and western redcedar both have

high potential future value for different markets, while the

western hemlock with a modest potential for future value

will offset epidemic potential of Douglas-fir pests. Browse

inhibitor application at the nursery is specified for both

western redcedar and Douglas-fir; deer browse for our area

has in the past been moderate.4 The proposition is that a

species mix is an effective measure to prevent pest epidemics, and that a mixture provides opportunities to exploit

market niches as they may occur for different species and

products. 

After several simulation runs with different planting

densities and thinning regimes, the silvicultural stand-rotation prescription in table 2 was chosen. This regime (1) has

the best probable progression to attainment of stand rotational wildlife and revenue objectives; (2) provides reforestation and site preparation prescriptions for near-present

execution that reasonably minimize the probability precommercial thinning will be needed while maximizing the

probability of success for the earliest commercial thinning

thought safely merchantable; and (3) provides densityrelated decision nodes to be scheduled in the corporate

database at which junctures the stand-rotation prescription

may be altered, should objectives change in the interim.

Additional simulations revealed an opportunity cost 

on the order of $600 per acre for a 70-year rotation without western redcedar versus a shorter 40-year rotation.

However, the site-specific opportunity to include a western

redcedar cohort to the 70-year rotation added approximately $300 to bare land value (BLV),5 thus halving the opportunity cost (a higher harvest value assumption for western

redcedar—see table 2—would have further reduced the

opportunity cost). A western redcedar cohort would not

appreciably increase the value of a shorter 40-year rotation;

western redcedar requires the 70-year rotation to gain 

superior value (as well as to develop into an intermediate

canopy suitable for roosting). Meanwhile, an intensively

managed 100-year rotation attained high-quality nesting

habitat at 75 years but caused a halving of bare land value

(BLV) as compared to the 70-year rotation with a western

redcedar cohort. Both the value enhancement from the

western redcedar cohort in the 70-year rotation and the

rapid deterioration in investment value caused by a

“stretch” objective of high quality nesting habitat in a

longer 100-year rotation are similar to findings of Latta 

and Montgomery (2007). 

SUMMARY

We have demonstrated a process to fine-tune activities

in the present to serve multiple objectives and long-term

intent by using concepts from current science in concert

with site-specific opportunities. We used an example with

both revenue and wildlife habitat objectives and demonstrated how enhanced value could accrue by capitalizing on

131

4 WDNR’s Webster Forest Nursery charges approximately one cent per seedling for an application that lasts in the field for around 3 months.

5 BLV = NFV ÷ [(1 + i) n - 1]. BLV is bare land value and NFV is net future value i.e., the net of all real value costs and revenues, each compounded 

until the end of the rotation. NFV= ∑FV wherein FV= V ÷ (1+i) n). V is the value of an investment or revenue; i is the compounding rate; and n is the

number of years in the rotation. Expressed differently, BLV is the net present value (NPV) of an infinite number of successive, identical rotations (NPV=

∑PV with PV = V ÷ (1 + i) n). Thus, because its investment period always is infinity, BLV, unlike NPV, is suitable for comparing investment value of 

differing lengths.
particular opportunities in site-specific execution of silvicultural activities. We also illustrated potential opportunity

costs incurred by ambitious wildlife objectives in a rotation

that nevertheless generated positive revenue. It appears that

such opportunity costs, even in the case of positive financial profit, may affect land use. We cannot disregard the

possibility that alterations to regimes required to accommodate wildlife habitat objectives may have negative effects

on competitive positioning in a worldwide marketplace as

it affects conversion of forestland to other uses. It is also

unclear to what extent opportunity cost of medium-length

and more complex rotations may be offset by decreased

risk to forest health and market opportunities offered by a

diverse inventory of standing wood. It is therefore plausible, as alluded to in the above example with the western

redcedar cohort, that innovation realized through site-specific execution at all stages of a rotation may convey financial gains routinely foregone in minimum-length intensive

monocultures. 

ACKNOWLEDGMENTS

Thank you to all who provided input and advice to the

writing of this paper, especially Bob Aulds, Angus Brodie,

Tim Harrington, George McFadden, and Gretchen

Nicholas.

132

Table 2—Silvicultural prescription summary for a 70-year rotation that manages sub-mature habitat for the northern

spotted owl in concert with landscape objectives

Year of Cash flow

occurrence (2006 

from present Event and associated activity prescriptiona dollars)

-1 VRH Prior Stand, leaving approx. 12 legacies/acre (snags, wildlife trees) and LDWD NA

0 Manual herbicide site prep. avoiding micro-sites suitable for hiding from browse WRC to 

be planted -$100

1 Plant a mix of 150 1+1 DF, 150 P+1 WH, and 60 P+1 WRC w/ browse inhibitor/acre -$200

4 Manual herbicide vegetation management -$100

12 Monitor for PCT—if projected, subtract $65 from BLV -$1

35 Enter habitat window; stand is now estimated to meet or exceed all threshold targets 

for sub-mature habitat

28 VDT from RD 65 to RD 45, removing equal amounts of DF and WH but leaving 

WRC; harvest 9.4 MBF/acre at $150/MBF $1,410

53 VDT from RD 65 to RD 50, removing equal amounts of DF and WH, leaving WRC; 

harvest 10.8 MBF/acre at $250/MBF and leaving 3 MBF as snag and LDWD replenishment $2,700

70 Pre-harvest 10 MBF/acre WRC at $750/MBF; VRH, leaving 10 MBF/acre as snags, 

wildlife trees, and LDWD while harvesting 39.2 MBF/acre of 2-saw or better DF and WH 

at 375/MBF $22,200

Results

• Bare land value (BLV)b at 4 Percent Discount Rate: $1,983 (exceeds $0 threshold)c

• Approximate internal rate of returnd: 7.65 percent (exceeds 4 percent threshold)

• Total investments: $401/acre (within $500/ac maximum threshold)

a Abbreviations used in the table have the following meaning: DF (Douglas-fir), LDWD (large down woody debris), MBF (thousand board feet), RD 

(relative density; Curtis 1982), VDT (variable density thinning), VRH (variable retention harvest), WH (western hemlock), and WRC (western redcedar), 

b BLV = NFV ÷ [(1 + i) n - 1]. BLV is bare land value and NFV is net future value i.e., the net of all real value costs and revenues, each compounded until 

the end of the rotation. NFV = ∑FV wherein FV= V ÷ (1+i) n). V is the value of an investment or revenue; i is the compound interest rate; and n is the 

number of years in the rotation. Expressed differently, BLV is the net present value (NPV) of an infinite number of successive, identical rotations. NPV= 

∑PV with PV = V ÷ (1 + i) n.

c The BLV gain is approximately $300 from planting and marketing western redcedar as a separate sort at final harvest

d Internal rate of return, IRR, is the discount rate for which NPV = $0 (for longer rotations, NPV approaches BLV).
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Service, Pacific Northwest Research Station: 107-116.

Thomas, J.W.; Bunnell, F. 2002. Objectives and principles for developing comprehensive plans for forest

biodiversity conservation. In: Lindenmayer, D.B.;

Franklin, J.F., eds. Conserving forest biodiversity: 

a comprehensive multiscaled approach. Washington,

DC: Island Press: 41-53.

Washington State Department of Natural Resources 

[WDNR]. 2004. Final environmental impact statement

on alternatives for sustainable forest management of

state trust lands in western Washington. Olympia, WA:

Washington State Department of Natural Resources.

Weetman, G.F. 1996. Are European silvicultural systems 

and precedents useful for British Columbia silviculture

prescriptions? FRDA report, ISSN 0835-0752; 239.

Victoria, BC: Canada-British Columbia Partnership

Agreement on Forest Resource Development: FRDA

II: Canada Ministry of Forests. 26 p.

134
135

METRIC EQUIVALENTS

When you know: Multiply by: To find:

Degrees Fahrenheit (°F) (F-32) x 0.556 Degrees Celsius (°C)

Inches (in) 2.54 Centimeters (cm)

Feet (ft) .3048 Meters (m)

Acres (ac) .4047 Hectares (ha)

Trees per acre 2.471 Trees per hectare

Square feet per acre (ft2/ac) .2296 Square meters per hectare (m2/ha)

Thousand board feet (MBF) .0024 Cubic meters (m3)

Fluid ounces .0296 Liters (L)

Gallons 3.78 Liters (L)

ENGLISH EQUIVALENTS

When you know: Multiply by: To find:

Degrees Celsius (°C) (C*9/5) +32 Degrees Fahrenheit (°F)

Centimeters (cm) .3937 Inches (in) 

Meters (m) 3.2808 Feet (ft)

Kilometers (km) 0.6214 Miles (m)

Square meters per hectare (m2/ha) 4.3560 Square feet per acre (ft2/ac)
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The Forest Service of the U.S. Department of Agriculture is dedicated to the principle of 

multiple use management of the Nation’s forest resources for sustained yields of wood, water,

forage, wildlife, and recreation. Through forestry research, cooperation with the States and 

private forest owners, and management of the national forests and national grasslands, it

strives—as directed by Congress—to provide increasingly greater service to a growing Nation.

The U.S. Department of Agriculture (USDA) prohibits discrimination in all its programs and

activities on the basis of race, color, national origin, age, disability, and, where applicable, sex,

marital status, familial status, parental status, religion, sexual orientation, genetic information,

political beliefs, reprisal, or because all or part of an individual’s income is derived from any

public assistance program. (Not all prohibited bases apply to all programs.) Persons with 

disabilities who require alternative means for communication of program information (Braille,

large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice

and TDD).

To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, 1400

Independence Avenue, S.W. Washington, DC 20250-9410 or call (800) 795-3272 (voice) 

or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Pacific Northwest Research Station

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Telephone (503) 808-2592

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P.O. Box 3890

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