United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical

Report

PNW-GTR-721

November 2007

AIMing for Healthy Forests: 

Active, Intentional 

Management for Multiple 

Values

Andrew B. Carey
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 were 

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.

Author

Andrew B. Carey is an emeritus research scientist, Forestry Sciences Laboratory, 3625 93rd Avenue, Olympia, WA 98512-9193.

Technical Editor

Annette S.B. Wilson is a biological science specialist, Forestry Sciences Laboratory, 3625 93rd Avenue, Olympia, WA 98512-9193.
Preface

P A R T I Social Aspects of Conservation

1 Conservation and Biodiversity

2 Culture and Conservation

A History of Conservation Ideas

Arcadianism and the Ecology Movement

Christian Pastoralism, the Imperial View

Arcadian Imperialism

Thoreau’s Romantic Ecology

Darwinian Ecology

From Ecology to Conservation

Contemporary Themes in Conservation

Compositionalism

Functionalism

A Fusion of Complementary Approaches

Conservation, Forest Management, and Sustainability

Forestry and Conservation

Reserves and Conservation

New Conservation Objectives

General Sustainability

Ecosystem Management

Total Landscape Management

Culture and Contemporary Players in Conservation

Cultural Streams in the United States

Leadership by Nongovernmental Organizations

v

3

9

10

19

21

22

25

26

29

30

32

35

1

11

12

12

12

12

13

22

49

51

51

53

Table of Contents
Managing Public Lands

Managing Private Lands

Property Ownership and Conservation

3 Individuals, Society, and Conservation

Ways of Thinking, Learning, and Knowing

Critical Theory and Green Political Thought 

The Role of Place in Conservation 

Communities and Conservation 

Social and Personal Evolution

Agencies, Organizations, and Society

Science, Scientists, and Society

Social Sciences

4 Conservation Revisited

Suggested Reading

P A R T I I Understanding Forest Ecosystems

5 Terms, Concepts, and Theories

Terminology

Theories, Frameworks, and Points of View

Panarchy Theory

6 Ecological Foundations of Biodiversity

Why Are There So Many Species?

Biogeography

Landscape Ecology

Fragmentation

Isolation, Connectivity, and Viability

Temporary Isolation

Dispersal and Colonization

Landscape Epidemiology

Landscape Mosaics

Landform Variability

Landform Analysis, Communities, Habitats, 

and Niches

Communities and Ecosystems

Self-Organizing Systems

117

136

130

129

126

120

118

156

154

150

147

168

166

163

160

157

176

180

115

55

56

57

59

62

73

76

78

80

96

97

99

107

113

ii AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Formation of Biotic Communities

Ecosystem Structure

Forest Structuring Processes

Ecosystem Development and Community Succession

Wildlife-Habitat-Relationships Models

Forest Development Models

Reserve Design

Washington Forest Landscape Management Project

Research Responses to the Old-Growth Crisis

Natural Forests

Old-Growth Versus Managed Forests

Modeling Landscape Alternatives

Implications

The Forest Ecosystem Study

Experimental Design

Soil Food Webs and Forest-Floor Character

Understory Plants

Small Mammals

Squirrels

Wintering Birds

Implications

Stochasticity, Disturbance, and Change

Hierarchy Theory

Panarchy Theory

7 From Ecology to Forest Management

Structure, Pattern, and Processes

Synthesis

Problems

Biological and Functional Diversity

Processes Underlying Forest Development

Exogenous Disturbances

Endogenous Disturbances

Crown-Class Differentiation

Decadence

Canopy Stratification

Understory Development

Development of Habitat Breadth

Spatial-Scale and Spatiotemporal Heterogeneity

202

201

181

185

191

200

207

206

204

204

214

213

209

208

221

220

215

222

238

235

228

227

225

223

223

222

258

254

245

244

238

297

275

267

321

319

315

324

T A B L E O F C O N T E N T S iii
8 AIM for Resilient Forests

Components

 Legacy Retention

 Multispecies Management

 SAVE Trees and Shrubs

 Planting, Underplanting, and Seeding

 Precommercial Thinning

 Commercial Thinning

 Decadence Management

 Rotation Age and Uneven-Age Management

 Landscape Management

Common Questions

 Will Plantations Develop Into Old Growth?

 Is Active Management Better Than Leaving

 Second Growth Alone?

 Will Active Management of Second Growth

 Produce Negative Effects?

Suggested Reading

Literature Cited

Appendix—Common and Scientific Names 

of Species

351

355

429

333

339

339

338

336

336

344

343

341

340

339

348

349

347

346

iv AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Preface

Conservation: the protection, preservation, management, or restoration of wildlife and of natural resources such as forests, soil, and 

water.

-The American Heritage Dictionary of the English Language

Why this book? In the last  years, societies everywhere have undergone rapid change in all aspects of life. New technology and globalization have accelerated use of natural resources, led to abandonment of customs and adoption of new lifestyles, and brought about 

changes in political systems and the roles of governments. This dynamism has produced closer ties among nations, placed nations in 

competition, and magnified the discrepancies in material well-being 

between developed and underdeveloped nations. Similarly, within 

nations, subcultures have drawn apart, each reacting to the challenge 

of meeting its own needs and perceived threats to its own values and 

beliefs in rapidly changing social environments. Even within the Pacific Northwestern United States, there are substantial subcultural 

differences that are displayed vividly in public arenas and in interactions with governments at various levels. Here, and elsewhere, differences are played out in disputes over disposition and conservation 

of natural resources.

Increasing human populations, large-scale immigration, large 

institutions, and a global economy have facilitated impersonal international exploitation of human and natural resources. Environmental problems are real, pervasive, and radically altering the conditions 

of life on Earth. Effects include global warming, decreasing oceanic productivity, desertification, ground-water depletion, and various forms of persistent pollution. These conditions raise substantial 

ethical questions of intragenerational equity and social justice (have 

versus have-not nations and groups within nations) and intergenerational equity (the kind of world we will leave to future generations), 
vi AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

1 Welch, C. 2004. Bush cut some diesel pollution but let big ships keep spewing. Seattle Times. 

http://seattletimes.nwsource.com/html/politics/2002048167_bushship28m.html. September 28, 2004.

as well as questions of effects on the general health and welfare of 

people. For example, adult asthma has increased fourfold in the Seattle area over the last 1 years as a result of particulates from diesel 

emissions and cargo ship bunker fuel pollutants.1 Such problems are 

international in scope and will require international, national, and 

regional action for resolution. 

A less spectacular and much less recognized problem is degradation of ecosystem function through neglect, unwise use, poor 

management, and lack of social consensus on how best to manage 

and conserve ecosystems. Not only is social consensus lacking, but 

there is also lack of consensus, even discourse, among the various 

sciences that inform the political and management processes that 

govern ecosystems. Ecosystem management is fragmented. Urban 

growth management, waste management, designation of transportation corridors, water use, and extraction of nonrenewable resources are largely made independently of efforts to conserve biological 

diversity and ecosystem function. The principal exceptions are instances where legislation protects wilderness, parks, refuges, or endangered species. Even within the Pacific Northwest, there is lack 

of coherence in management and lack of management on private, 

industrial, state, tribal, and federal forests. Management of different 

ownerships is informed by different worldviews, values, and subsets of 

pertinent scientific information.

Even the small stage of the Pacific Northwest is changing rapidly in response to globalization. Traditional low-intensity forestry 

on public, industrial, and family-owned forests may become economically unsustainable and, in the interim, environmentally and 

socially undesirable. Costs of producing wood given wages, workers’ 

rights, and environmental protection are too high to compete with 

imported wood, whether from labor-intensive and publicly subsidized extraction from unmanaged forests or highly mechanized, intensively managed pine plantations. 

Thus, local and regional publics are faced with a new problem, 

one that appears not to be amenable to national or international, 

top-down solutions: How do we maintain the life-support functions 

(ecological services) of our natural and managed ecosystems, restore 

function to degraded watersheds, and provide the various other values from farms, forests, and rivers that we and our fellow citizens 

would like to receive and keep available to future generations? How 

do we reconcile our increasing demands for diverse and seemingly 

competing values: clean air; high-quality and large quantities of water, food, wood, fiber, fish, recreation, open space, wildlife, wilder-
P R E F A C E vii

ness, wildness, biological diversity; and respect for the rights of other 

species to exist (already codified in the Endangered Species Act; 

Migratory Bird Treaty Act; National Forest Management Act; and 

other federal, state, and local laws and regulations)? Can we recon-

ceive the natural-cultural agricultural mosaics of the preindustrial 

age and match the new concept to our present and future needs? At 

best, these mosaics contributed to sustainability—clustered dwell-

ings (villages) imbedded in forest reserves, wetlands, small fields 

(fallow and cultivated), and pastures matched to soils and topog-

raphy and integrated into a mosaic that maintained environmental 

quality and renewable resources. These arrangements often contrib-

uted to intragenerational equity with a fair spatial distribution of 

agricultural fields and pastures—fair because fields were small and 

ownerships scattered providing incentive to community coopera-

tion in planting and harvest and equitable in distances traveled for 

cultivation. We cannot return to preindustrial farming economies 

(some of our fellow citizens have and will), but we can intentionally 

integrate wetlands, forests, and other native ecosystem types, man-

aged to perpetuate their natural values, into our urban, suburban, 

agricultural, and transportation matrix. However, as we move out 

from our highly developed population centers can we intentionally 

maintain forests managed for multiple values—to provide clean air, 

clean water, diverse biotic communities, wildness, and natural aes-

thetics and opportunities for physical and spiritual renewal? And, 

in the process, buffer our fragile wilderness areas and other nature 

reserves? Finally, can we come to some consensus on total landscape 

management and provide limits to the growth of urban and subur-

ban areas and to the destruction of managed and natural forests? 

This book seeks to inform the deliberations of dedicated and 

well-informed citizens interested in the conservation of forest eco-

systems at the local, state, and regional scales by using the Pacific 

Northwest as an example. Citizens are defined here as the various 

interested private individuals, interest groups, land managers, tech-

nical staffs, regulatory agency staff, local governments, tribal repre-

sentatives, and other active agents who are likely and disposed to 

participate in collaborative learning and collaborative management 

efforts. Many of these people will be paid professionals in the various 

disciplines related to conservation, natural resources management, 

community development, organizational development, governance, 

and economics. But many will also be citizen volunteers (often pro-

fessionals in unrelated or related fields as well) who operate at a 

professional level in collaborative management efforts. This book is 

not designed, however, to be used as a how-to recipe or tool for col-
viii AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

laborative management. Instead, it is meant to provide an overview 

of collaborative management, forest ecology, and conservation at a 

professional or postgraduate/continuing education level.

 It is at the local and within-state level that collaborative learning and collaborative management can take place and that a social 

consensus can be achieved, which will restore trust among parties 

now in adversarial relationships. Forestry, like collaborative learning, 

collaborative management, and consensus building is based in social 

sciences. Success in integrated management rests on understanding cultures, worldviews, modes of communication and learning, 

personalities, personal development, and group dynamics as much 

as they depend on understanding biogeography, landscape ecology, ecosystems, evolution, ecotypic adaptation to local conditions, 

and self-organizing biotic communities. Few are equipped with the 

cognitive breadth to pay adequate attention to the details of sociology, psychology, and ecology in conflict-laden natural resource 

arenas. Often the mind that revels in technical, ecological detail is 

refractory to psychology and sociology. Mutual understanding of 

environmental, economic, and social challenges in natural resource 

management, restoration of trust, and consensus on what constitutes environmental, social, and economic sustainability must be 

achieved before the general public can be motivated to support sustainable forest management through their market and political decisions. This might include the willingness to pay higher prices for 

products, subsidize sustainable management through higher taxes 

to compensate socially minded land managers and state-land trusts 

for their contribution to general well-being, and purchase valuable 

forest ecosystems (or their development rights) that are no longer 

perceived by their owners to be economically viable wood-producing enterprises. People value and benefit from forests, whether as 

individuals or part of private, industrial, state, tribal, or federal organizations. The ecological services derived from forests—clean air 

and water, open space, waste assimilation, climate regulation, wildlife habitat, recreation opportunities, and so on—have more value 

than the marketable commodities. We must recognize and pay for 

these services if we are to maintain our quality of life and to provide 

options for equivalent quality lifestyles to future generations (fig. i).

AIMing for Healthy Forests

The focus of this book is active, intentional management (AIM) of 

forest ecosystems: taking AIM so as to provide general sustainability 
P R E F A C E ix

Figure i Aiming to conserve biodiversity for future generations—Calum 

Maki, the author’s grandson, enjoys a 

day hiking and hanging out with his 

grandparents near Granite Lake in 

the Gifford Pinchot National Forest, 

Washington. Photo by R. Carey. 

and to achieve the full range of social, economic, and 

environmental goals society has for its forests. Management is active when it uses the full range of tools 

available for landscape, watershed, and local ecosystem 

management, including a variety of tools beyond the 

scope of this work: (1) removing roads and/or improving roads, establishing effective transportation systems, 

and other ecological engineering practices; () removing or replacing culverts, stabilizing eroding road cuts, 

placing instream structures, and other hydrological 

management; () identifying areas of soil or geologic 

instability, limiting activities to those appropriate to 

these areas, and other geomorphological planning; 

() identifying and protecting unique ecological or 

biological areas and other site-specific conservation of 

unique elements of biological diversity; and () identifying and establishing nature reserves, wildlife refuges, and wildernesses. These activities are becoming 

institutionalized in agency regulations and state forest 

practices rules, and many will be cited as sources in 

this book. This is not to say that issues surrounding roads, unstable 

slopes, and preservation of biological diversity have been resolved; 

they have not, and this book will not attempt to resolve them either. 

Instead, the book focuses on ecological forestry that includes silviculture, direct wildlife habitat improvements, restoration of biological diversity, and maintenance of dynamic local ecosystems in mosaic landscapes where biological diversity and ecological processes 

are maintained by (1) a composition that emphasizes biologically 

complex stages of forest development and () a dynamic condition 

in which locations of seral stages change with time as local ecosystems go through cycles of development and renewal.

The focus is also on intentionality—developing management 

systems that purposefully set out to address the values of a pluralistic public, reconcile various conservation philosophies, and integrate 

multiple scientific disciplines. In the last two decades, substantial 

research and practice in organization function and business practices have led to some general conclusions about how to organize 

any management effort—for example, decentralized management, 

with resources going to the front line where lead managers can most 

clearly identify the stakeholders and the nature of their demands. 

The relationships among people at each step in management processes need to be carefully and fully negotiated, such that each side 

of the junction has rights, responsibilities, and accountability for 
x AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

the decisions made. And, importantly, people must be free to make 

decisions. For instance, neither environmentalist, nor regulator, nor 

manager can sit back and demand—all must put forth, engage, and 

contribute to resolution. No “line officer” or executive higher-up in 

an agency or organization hierarchy can violate the social and psychological contracting such hard-won consensuses entail with an 

imperious veto. It is this kind of veto that contributes to developing 

the present air of intense mistrust. To be intentional, management 

must be collaborative and based on collaborative learning. No one, 

nor any one group or group of agencies, has a monopoly on facts or 

truth or the capacity to integrate various social and economic public 

values and effectively communicate that integration. Nor can such 

values be aggregated regionally and then homogenized and directed 

downward again and still be appropriate. National and regional priorities can be transmitted downward by the actions of legislatures 

and auditors appointed for that purpose. Regional inventories, analyses, and policies provide useful information, but multilayered planning just gets in the way. In multilayered planning scenarios, most of 

the resources go to regional planning and to support technical staff 

at the regional level, well-removed from local specifics.

 Just as cookbook silviculture cannot achieve diverse goals in 

the diverse Pacific Northwest landscape, neither can top-down socioeconomic formulations. Thus, we need to begin to decentralize 

planning and management by shifting human and financial resources to the front lines and drawing on the diverse local publics and 

their knowledge of needs, wants, desires, and ecology. Collaborative 

management means incorporating representatives of all stakeholders and management by consensus, not by compromise. It will be 

difficult when there are so many groups at odds with each other; the 

redeeming feature of such conflict is that it can only be overcome 

by true creativity. 

This is not a book on psychology or sociology, but conservation 

and forest management entail as much, if not more, social science 

as ecological and economic sciences. Thus, the book covers cognitive 

psychology, the psychology of personality, psychological contracting, worldviews, cultural streams, social contracting, and the roots of 

conservation philosophies, in hope that understanding the sources 

of differences in perception, learning, knowing, communication, 

beliefs, and values will help ease the pain and increase the joy of 

collaboration. The pain will diminish as fear, distrust, poor communication, unwarranted assumptions, and defensiveness wane, and joy 

will increase as discovery reveals the unique human qualities, life 

experiences, and sincerity of each of one’s collaborators. Not all per-
P R E F A C E xi

sonalities will function well in collaborative management settings; 

ones that do not can still play valuable roles in collaborative learning 

and information providing. Here again, we do not have to start from 

scratch. There is a huge literature, a variety of methods, and a profes-

sion of facilitation that has developed over the past  years to bring 

together individuals and groups in conflict. The Pacific Northwest 

has a decades-long history of attempts at collaborative management, 

including the Quincy Library Group, the Applegate Partnership, 

and various Forest Service provincial advisory committees.

Finally, this book seeks to fill the need for integration across sci-

entific disciplines whose various worldviews suggest profoundly different priorities and approaches to ecosystem management. A landscape ecologist expresses the need to manage landscapes within the 

range of historical variation; a conservation biologist sees the world 

as composed of reserves and connecting corridors; forest ecologists 

emphasize biological legacies, biodiversity, ecosystem processes, and 

management of various “structures;” an evolutionary biologist fears 

loss of genetic diversity, even within a subspecies or an individual 

tree; a forester dreams of highly efficient fiber production and tech-

nological agroforestry; wildlife biologists variously focus on snags, 

elk and deer, Neotropical migratory birds, or spotted owls. Tradi-

tional economists have their views, quite different from those of 

the ecological economist. Social scientists hover around the edges, 

working with communities and other social institutions. How can 

such a cacophony be brought into some kind of harmony?

Systems theory helps. Pragmatists have always turned to sys-

tems concepts, and there is a long history in ecology from Eugene 

P. Odum to C.S. Holling, with the current version being called Pan-

archy theory. Beyond Panarchy is Ken Wilber’s holarchy in which 

everything is a whole in itself, composed of parts, each part a whole 

in itself, and each whole contributing to a larger whole, which, again, 

is a part of yet another large whole; thus, everything is a whole/part 

and can be placed in hierarchy that is free of subordinate-dominant 

relationships. A characteristic of holarchies is that complexity in-

creases with each level, and one can distinguish between levels in 

that the lower level is essential to the higher, but the higher is not 

essential to the lower. For example, the natural environment is es-

sential to an economic system of resource use, but if the economic 

system is removed, the environment remains. An economic system 

of resource sharing is essential to developing a complex society, but 

the nature of that society could change markedly while the econom-

ic system remains intact. Markedly change the economic system and 

society must change. Panarchy insists ecosystem management must 
xii AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

be viewed within the context of human social and economic systems. 

Holarchy suggests that not only is such hierarchy appropriate but 

that ecosystems, individual humans, and cultures exhibit patterns 

of development. These patterns suggest that collaborative management not only necessitates understanding ecosystem function and 

human wants and needs but also requires personal growth and social 

development. This means moving away from self-centered thought 

on a personal level and tribal- or interest-centered thought on social and scientific-discipline levels and moving toward decentered 

views. When the individual and group can step away from self and 

their natural tendency to pursue a dominator hierarchy and observe 

the world in its whole-parts—a move from magic-mythic, mythicrational, and economic rational thinking to what Wilber calls vision-logic—then we have a chance of achieving a common vision 

and consensus on solutions to complex problems. Therefore, there is 

a systems focus to this book. This book is not offered as a panacea 

or a difficult and complex solution to our conservation problems, or 

even a handbook of methods. Rather, this book provides hopefully 

one basis for collaborative learning and collaborative management 

of forested ecosystems (figs. ii, iii). 

I dedicate this book to Robert H. Giles Jr., who in the late 1s 

taught me how to think—systems thinking, hierarchical structures, 

and deconstructing complex problems; to Robert G. McLean, who 

introduced me to ecological fieldwork and invited my participation 

in multiple investigations of complex ecological systems (pathobiogeocenoses); to Jerry F. Franklin, who introduced me to Pacific 

Northwest old-growth forests and who has been a -year source of 

inspiration and discussion; and to Chuck DeRidder, who taught me 

the value of openness to others, teamwork, understanding cognitive 

differences among people, and the need for examining the structure 

and function of human organizations.

I wish to acknowledge the following for their support and 

funding: Nancy Diaz, Issue Coordinator, Sustainable Management 

Strategies; John Laurence, Program Manager, Ecosystem Processes 

Program; and Jamie Barbour, Program Manager, Focused Science 

Delivery Program. I also thank other members of the Ecological 

Foundations of Biodiversity Team, especially Todd Wilson and 

Thinh Nguyen, for their assistance and valuable suggestions. I thank 

Annette Wilson for the attention to detail she has paid in editing 

drafts of this book, and her creativity in designing tables, figures, 

sidenotes, and general layout.

Andrew B. Carey
P R E F A C E xiii

Integration of psychology, 

sociology, ecology, and 

increased personal efficacy

Personal and professional growth

Ethical stance on intragenerational 

and intergenerational equity, justice, 

and land stewardship

Desire and intention to participate in 

active, intentional management for 

multiple values

This requires understanding...

1. The history of conservation ideas―understanding the timelessness and validity of 

various values for nature, the origin and 

current status of various current worldviews, and concepts of sustainability.

2. The sociology and psychology of conservation and collaborative managementunderstanding the roles of individuals and 

society in conservation and how individuals 

differ in how they think, learn, and communicate; understanding the need for 

personal development of effectiveness in 

group and conflict settings; understanding 

how individuals and societies develop from 

reliance on mythology to more integrated 

views and the ability to take decentered 

views; understanding the need for organizational evolution to be effective in meeting contemporary and future conservation 

challenges; understanding how societal 

evolution suggests new roles for scientists 

as facilitators; and understanding the 

necessity for social scientist participation in 

conservation.

3. Ecological foundations of biodiversity—the 

complexity and processes underlying the 

ability of forests to produce goods and 

services.

4. From ecology to forest management—how 

to take what we know about how forests 

work and develop it into a way of managing sustainably.

Effective Ecology-Based Collaborative

Learning and Collaborative Management

Figure ¡¡
xiv AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Social

Factors

Personal

Factors

Ecological

Knowledge

Success or

Lack of Success

in Collaboration

X X

-Cultural streams in the United States

-History of conservation philosophies

-Differences in worldviews

-Differences in cognitive preferences and communication

-Differences in sources of information

-Differences in basic values

-Can we value others?

-Can we take their point of view?

-Can we explain their point of view?

-Can we accept their SOMETHING?

-Can we take a decentered view in a group process?

-A common terminology for ecology

-A common understanding of concepts

-A common knowledge based on group experience in the forest

Equation for Successful Collaboration Equation for Successful Collaboration

=

Figure ¡¡¡
P A R T I

Social Aspects of Conservation
P A R T I Key Points

 Conservation of nature has a long history in human societies 

and is common to virtually all philosophies of the use of natural 

resources.

	 Society derives diverse values from forests, and forests form a 

large part of the life-support system for human societies.

 Groups differ in value emphasis in forest management, but 

practically all recognize sustainability as key to human welfare.

 Reconciliation of differences in values may be achieved best by 

collaborative learning and collaborative management at the local level.

 The ability of individuals to participate effectively in collaborative management not only depends on their willingness to do 

so, but also on their ability to take a decentered view of conflicts 

that arise.
C H A P T E R 1

Conservation and Biodiversity

This book is about conservation in the context of sustainability—

environmental, economic, and social. Before addressing the environmental and economic aspects of conservation, I must first place conservation in a larger, overarching social context of the United States 

and, more particularly, the Pacific Northwest. Conservation calls for 

more than the application of technology; it requires a collective purpose (Leopold 1). But our society is diverse. Perhaps our society’s 

most fundamental aspect is its promotion of each individual’s right 

to define his or her self—personally, socially, occupationally, culturally, politically, spiritually, and philosophically. Each of us is free to 

perceive and report reality in our own way. Our common language, 

English, promotes such individualism. The conceivers of the Oxford 

English Dictionary, the first comprehensive dictionary of the English language, recognized and accepted English as an ever-changing 

language, and they made their dictionary a continuing effort (1-

present) to inventory, not prescribe the language (Winchester 1). 

To them, word meanings were not static but continuously wandering, twisting, and turning over time. Human diversity, dynamic 

language, and different ways of learning prompt defining reality in 

terms of one’s self over reliance on scholarship and formal discourse 

to achieve a shared view. Even our tendencies toward safekeeping 
4 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 2—Many find 

conservation concepts ambiguous; 

this ambiguity, however, may be 

perceived because many of these 

concepts are multidimensional 

and metaphoric. Pickett (2000) 

defines ecosystem as “an ecological community together with its 

environment, functioning as a 

unit.” Pickett and Cadenasso 

(2002) found that “ecosystem” is 

a fundamental ecological concept 

that is complex and subtle with 

Sidenote 1—Four types 

of restorationists participated 

in three widely separated river 

restoration efforts (Woolley and 

McGinnis 2000):

 Categorical: regards restoration as factually necessary and 

ethically mandated to a state 

prior to human settlement; 

sees restoration as an article of 

faith

 Conditional: believes restoration may be justified and technically feasible only if competing claims can be addressed; 

emphasizes private property 

rights, local control, tradeoffs, 

and cultural values

 Ecophilosopher: distrusts 

science and technology and is 

critical of values for restoration 

and community needs; has the 

deepest feelings for wilderness 

and preservation; does not 

believe nature can be restored; 

believes restoration is impossible and its products false; sees 

restoration as an act of human 

domination over nature

 Ecosocietal: thinks restoration 

is a philosophy and political 

enterprise and must involve 

society and community restoration

and cultural conservatism, determinants of our past evolutionary fitness, fail to stem this drive toward autonomy.

Our emphasis on individualism extends into science, where 

rejecting an existing hypothesis and creating new theories are valued over affirming hypotheses and synthesis (Wilson 1). Furthermore, “For every expert there is an equal and opposite expert” 

(Clarke 1). Even more problematic, ecology is grounded in words, 

not in the precision of mathematics. Because of the imprecise and 

changing nature of words in English, the science of ecology has 

been slow to advance in comparison to mathematical sciences and 

their precise, unvarying definitions (Haskell 1). Disputes become 

based on semantics and caricatures of concepts developed by embellishment, selective editing, and oversimplification (Partridge ). 

Furthermore, scientific perception is theory bound—two different 

and equally objective scientists can observe the same natural system 

and provide very different descriptions of what they observed, depending on the language they choose, the assumptions they make, 

and the values that motivate them. These descriptions may or may 

not be contradictory. Because scientific claims are not value free, 

science, especially ecology, is rife with disputes rooted in conflicting values and epistemologies (Woolley and McGinnis ) (sidenote 1). Furthermore, the imprecision of the English language led an 

eminent and well-published psychiatrist, Stoller (1985), to conclude 

that no matter how mightily he strove for clarity, there would still be 

multiple, valid interpretations of what he wrote. 

Ecology, the science of relationships between organisms and 

their environment (Pickett ), has progressed through iterative compilations of natural history observations, verbal conceptual 

models, and mathematical formulations, with occasional important 

contributions from experiments. Imprecision and a variety of words 

have led to hypotheses and theories that are often challenged because of superficiality, circularity, and infallibility (Peters 1976, 1978; 

Quinn and Dunham 1983). This considerable ambiguity in the use 

of terms has produced a science that lacks clear baselines, boundaries, explicated concepts, and theoretical rigor (Partridge 2000) (sidenote 2). Such concerns led the distinguished ecosystem ecologist, 

R.V. O’Neill (2001) to ask, somewhat tongue-in-cheek: “Is it time to 

bury the ecosystem concept?” citing backlash from the “apocalyptic 

fervor of the environmental movement of the past decades.” It is 

now too late for science to define authoritatively concepts related 

to conservation; science no longer has the moral authority to do so 

in our culture. The privilege accorded science in the modern world 

relied on science being objective in describing how the world works; 

in the postmodern world, a single truth does not exist. 
C H A P T E R 1 Conservation and Biodiversity 5

layers of meaning. Ecosystem has 

three uses: meaning, model, and 

metaphor. Its meaning is usually a technical definition, which 

requires detailed definition for 

each application. As a model, it 

embodies details that are needed 

to address real or hypothetical situations. As a metaphor, it informs 

scientific discussions, common 

parlance, and public dialogue. The 

earliest definition of ecosystem 

is “a biotic community and its 

associated physical environment 

in a specific place” (Tansley 1935). 

This implies a nested hierarchical 

system—size can vary, but it must 

have an explicit spatial extent, 

specified and bounded—and this 

is the way that prominent ecologists of the past (Tansley, Odum, 

and Likens) perceived ecosystems. 

In modeling, ecosystem has been 

used for diverse foci, including 

energy and nutrient cycling, autecology of organisms, community 

ecology, biodiversity, and ecological economics. Thus, ecosystems 

have four domains that need to be 

specified: components, spatiotemporal scale, physical boundaries, 

and connections among components. These components can be 

geophysical, biological, and social. 

Boundaries can be chosen as a 

matter of convenience to follow 

geomorphological divides (most 

common), to understand a political entity, to recognize changes in 

rates of ecosystem processes, or to 

measure changes in frequency of 

some ecological phenomena.

The Procession of Species, a yearly 

artistic pageant where community 

members celebrate their relationships 

with each other and with the natural 

world. Photo by A. Carey.

Science of intrinsic quality now needs narratives with explicit 

values—not just facts—particularly as it faces multilevel complexity 

in environmental issues (Allen et al. 2001). Traditionally, scientists 

and conservationists have worked independently of each other, as 

well as the people affected by their decisions (Adams and McShane 

1992). Today, various “concepts are at large in the world, shaping conservation thought and policy” (Callicott et al. 1999) (side 

note 3). Many find the terminologies of conservation to be ill-defined, nakedly value laden, irritating, and even contentious, whereas 

others find them normative, meaningful, and even uplifting. Often 

conservation concepts are described as buzzwords and rhetorically 

dismissed as lacking substance. Even so, these terms are in the public 

lexicon, the culture of conservation, written policy, laws, and treaties, 

and they have inescapable consequences for stakeholders, regulators, 

managers, and policymakers.

Humans search for simple and clear principles, without uncertainty. Our behavior is shaped of necessity by concerns that are personal, immediate (short term), and certain (Daniels 1989, Ornstein 

and Ehrlich 1989). These characteristics reflect an intuitive tendency 

to parse our environment and experiences into discrete, bounded 

wholes. Some of this may be “hard-wired” in our brains and is one 

reason that umbrella concepts have such appeal (Anderson 2001) 

(sidenote 4). Nature, however, is simultaneously mechanistic and 

stochastic, and thus, presents substantial ambiguity and complexity, 

just as many conservation concepts do. 

Ambiguity is unsatisfying and can lead to unwarranted rejection 

of concepts and searches for nonexistent certainty and specificity. 

Thus, conservation of biodiversity can be a useful concept to some (e.g., 

Carey and Curtis 1996, Hansen et al. 1991, Reid and Miller 1989), 
6 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 3—Concepts at 

large in the world shaping conservation thought and policy that 

are generally either ill defined 

or defined differently by various 

groups (Callicott et al. 1999):

 Adaptive management

 Biological diversity

 Biodiversity 

 Biological integrity

 Conservation

 Ecological integrity

 Ecological restoration

 Ecological services

 Ecological sustainability

 Ecosystem health

 Ecosystem management

 Flagship species

 Functional groups

 General sustainability

 Keystone species

 Habitat fragmentation

 Minimum viable populations

 Source-sink dynamics

 Survey and manage species

 Sustainable development

 Umbrella species

only to be rejected in the same scientific arena as useless because 

it lacks a universal specific meaning (Lautenschlager 1997). Similar 

treatment has been accorded to niche, habitat, ecosystem, keystone species, ecosystem management, conservation, and most other terms in the 

debate over disposition and management of our natural resources 

(Carey 1981, Morrison 2001, Whittaker et al. 1973). Therefore, common words used in this book are defined according to their primary 

definition in the fourth edition of The American Heritage Dictionary of the English Language (Pickett 2000) but with reference to the 

online Oxford English Dictionary for history of usages. Additional 

definitions of technical terms are provided in the text, sidenotes, 

and glossary. The purpose in providing these definitions is to give 

participants in collaborative learning and collaborative management 

a source of common language, if they care to use it. No one should 

presume to mandate definitions.

The focus on semantics is not whimsical (Hardin 1969). Semantics, rather than logic or science, accounts for much of the current 

debate about conservation—the protection, preservation, management, or restoration of wildlife and of natural resources such as forests, soil, and water (Pickett 2000). In this debate, terms become 

normative—of, relating to, or prescribing a norm or standard (Pickett 2000). Thus, there is active competition to have one’s definition 

become accepted by a majority because thereby a social standard 

comes into being. Partisans of a single normative concept try to vanquish the rest in a battle of definition of buzzwords in the arena of 

power politics (Callicott et al. 1999). Commonly, “good science is 

that which supports one’s political position and interests” (Woolley 

and McGinnis 2000).

Freudenburg (2002) refers to this politics of language as “navel 

warfare” (as in gazing at one’s navel), concluding that exaggeration 

of differences between both environmental and resource sociology 

produces a divide where synergy could exist. Viewing the environment in terms of profit produces resource managers instead of environmental managers. Viewing a need to preserve broader ecosystems 

fosters protection and restoration over environmental management. 

Academics exhibit the “best of minds, the worst of minds” in the 

debate. At best, they use highly developed abilities to spot patterns, 

think abstractly, construct models, and work and play with models. 

At worst, they take mental models too seriously and forget the original purpose. Debate over management choices, rather than focusing on opportunities for synergy, often focus on false dichotomies 

(Haynes and Monserud 2002, Haynes et al. 2002). Conflict over 

policy has evolved into nonlistening conversations with the same 
C H A P T E R 1 Conservation and Biodiversity 7

Sidenote 4—Anderson (2001) 

describes three pairs of evolved 

abilities and their corresponding 

difficult cognitive tasks:

 Packaging information: 

recognizing things as discrete; classifying and naming 

categories

Difficult task: Dealing with 

continuous processes (working 

across scales; managing problems without clear boundaries)

 Focusing on frequencies: 

counting instances; interpreting counts as frequencies

Difficult task: Using decimal 

probabilities (estimating probabilities of single events; working with probability theory)

 Telling stories: telling stories 

to share experience; using 

cases as a basis for decisionmaking, problem-solving, 

and learning

Difficult task: Making decisions in the absence of experience (solving unique problems; 

communicating theory and 

abstractions) 

Interestingly, the evolved abilities and corresponding difficult 

cognitive tasks also relate to the 

IQ measure, with lower, initial 

points earned for recognizing 

types and using past experiences 

to solve similar problems and 

applying past experience to novel 

problems (evolved abilities) and 

subsequent additional points 

earned for creating novel solutions to novel problems (more 

difficult cognitive task). In other 

words, evolved abilities form the 

basis for low to average IQ, and 

the corresponding difficult cognitive tasks are characteristic of 

high IQ.

nearly century-old arguments of Gifford Pinchot and John Muir 

being restated with little new in the way of reconciling principles 

(Callicott et al. 1999). Realizing the futility in searching for decisive 

terminology and, instead, embracing ambiguity and seeking understanding and communality will help achieve consensus in management debates. In the following sections, this book will offer some 

temporary clarity in terms and concepts.

Conservation inescapably entails some aspect of conserving 

biodiversity. Biodiversity is the variability among living organisms 

on the earth, including the variability within and between species 

and within and between ecosystems (Pickett 2000). Many variations 

on this definition exist that are reflective of various worldviews and 

conservation priorities. The definition of biodiversity prompts the 

question: Why conserve biodiversity? The simple answer is multifold: legal mandates; social and cultural mandates; instrumental values such as wood products, medicines, and ecosystem services; and 

importance to sustainability. Loss of biodiversity, along with ozone 

depletion and greenhouse warming of the Earth’s atmosphere, are 

global environmental problems dominating environmental discussions (Norton 1994). 

The most common related questions are: What should we save—

genes, species, or ecosystems—and how many, where, when, for how 

long (Amaranthus 1997, Franklin 1993b)? To many, deciding what 

elements to preserve is a policy decision to be based on societal priorities. To others, it is a profoundly ethical and moral question. Are 

any species superfluous? We do not know, and it is possible we will 

never know for sure. Most species are unknown. And as Tacitus (54–

119 AD) said “Omne ignotum pro magnifico,” or anything unknown is 

assumed wonderful (Bigg 2000), at least by a significant proportion 

of stakeholders. Based on current knowledge, the odds are that there 

is enough redundancy that loss of a species could be inconsequential 

(to species other than itself and its obligative symbionts). Are some 

species more influential than others? Of course, they are. In any case, 

given our vastly incomplete knowledge of species, conservation must 

focus on surrogates for the totality of genes and species. Even if we 

do the impossible and identify and describe the ecologies of all species, it would be far beyond our cognitive capabilities (even aided by 

computers) to use all that information; we must formulate and apply 

some first (general, basic) principles. 

A less common question, but perhaps more important is: How 

can we restore and maintain biodiversity in our humanly inhabited 

natural-cultural mosaic landscapes? In other words, how do we manage for biodiversity? There are four basic options: ecological reserves; 
8 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

active, intentional, ecosystem management; reserves and management in combination; and total landscape management (Carey 

2003a, 2003c). The belief that we can achieve our conservation goals 

simply through passive management, however, is fallacious (Agee 

2002). And finally, how do we measure success? Here, the answer 

is least clear. There is no single measure. There is no agreement on 

a suite of measures. Various people suggest monitoring species persistence (often rare, cryptic, and threatened species), invasion by 

exotic species, diversity of various groups of vertebrates and fungi, 

functional groups of plants and invertebrates, keystone species, biotic integrity, ecosystem structure, ecosystem processes, or landscape 

structure and dynamics. Norton (1994) said: “Whilst it is not seriously questioned that there is an incumbent moral obligation for us 

to sustain biological diversity for the benefit of future generations, 

we still have to find the rationale for consensus and to articulate it 

in a specific and operational manner.” Dombeck (1997) added: “Just 

how do we maintain the health of the land? By working with people 

who use and care for the land.”
C H A P T E R 2

Culture and Conservation

Biodiversity was introduced into the scientific lexicon by Walter G. 

Rosen in 1986 during the national forum on biodiversity for educators and policymakers and quickly became integrated into the national vocabulary (Weber and Word 2001). But human fascination 

with the diversity of life certainly arose with human consciousness 

and continued throughout the evolution of human culture from 

hunting and gathering to agriculture to the present (Wilber 1995). 

Exploitation of natural diversity allowed the development of increasingly intricate social and economic systems (Diamond 1998, 

Hutchinson 1965). Aldo Leopold (1897–1948) wrote: “Wilderness 

is the raw material out of which man has hammered the artifact 

called civilization” (Leopold 1949).

The diversity of living things captivated early ecologists. 

Hutchinson (1965) recounts the studies of variation in Lepidoptera (butterflies) by Gilbert Henry Raynor (1854–1929) that led to 

the discovery of sex-linked inheritance almost concomitantly with 

Mendel’s discovery of the genetic basis for inheritance. Fascination 

with the diversity of life led to the theory of evolution that underlies 

modern biology and biomedicine. The question of why there are so 

many species dominated ecology in the first half of the 20th century 

(Hutchinson 1959) and led to the concept of the multidimensional 
10 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

niche (Hutchinson 1957), community ecology (Whittaker 1975), 

and statistical-mathematical ecology (Pielou 1975, 1977, 1984).

Emphasis on conservation of biodiversity (nature, including biological diversity and ecosystems) certainly preceded 1986 by more 

than 50 years. Aldo Leopold (1949) formulated the Golden Rule of 

Ecology with “A thing is right when it tends to preserve the integrity, 

stability, and beauty of the biotic community. It is wrong when it 

tends otherwise.” Leopold’s writings contained many of the words 

and concepts (integrity, stability, health) that are now being used 

and contested in the great debate on how to conserve our natural 

heritage. He certainly recognized our different values (table 1): “I 

am amazed to learn what diverse characters different men impute to 

one and the same tree” (Leopold 1949). Leopold also acknowledged 

the countervailing tendencies of human nature and the paradoxes 

therein: “But all conservation of wildness is self-defeating, for to 

cherish we must see and fondle, and when enough have seen and 

fondled, there is no wilderness left to cherish” (Leopold 1949). 

Still, we find ourselves in polarized, adversarial positions about 

conservation. The last 20 years has seen an explosion of philosophical, scientific, and technical discussions of conservation (Woolley 

and McGinnis 2000). What is important in conservation? How real 

is the need to conserve biodiversity? How might we best attempt to 

conserve our natural heritage? How should we implement adaptive 

management? What kinds of things should we measure and monitor? What research will best serve the conservation community, interested publics, and society at large? These are a few of the questions we need to address. A review of how we got here might help.

A History of Conservation Ideas 

Donald Worster (1994) recounts five roots for today’s ecology: Arcadianism, Christian pastoralism, Arcadian imperialism, Thoreau’s Romantic ecology, and Darwinian ecology. Worster is summarized here, 

not to bore the reader with esoterica, but to highlight the power of 

ideas and demonstrate how most historical ideas about nature are 

still extant in contemporary culture. These ideas are far more than 

artifacts of the interaction of culture and nature. They may be psychologically fundamental (archetypal) and biologically based (evolutionarily selected), as suggested by some Jungian psychologists 

for the multiple bases of temperament and personality (Myers and 

McCaulley 1985, Ornstein 1993). If so, it is even more important to 

understand them because simple, rational discourse is unlikely to 

reconcile their differences.
C H A P T E R 2 Culture and Conservation 11

Table 1—American values regarding forests and grasslands and their importance

Value Mean (out of 5)

Individual values:

People should be more concerned about how public lands are used. 4.8

I’m glad national forests are there even if I never see them. 4.7

Future generations are as important as the current generation in public lands decisions. 4.5

Wildlife, plants, and humans have equal rights. 4.3

Natural resources must be preserved even if some must do without. 4.1

Forests have a right to exist for their own sake. 4.1

We could get by with less and leave more for future generations. 4.0

Individual values group mean 4.2

Management values:

We should conserve now to allow development in the future. 4.0

We should provide jobs. 3.2

The primary use of forests is products useful to people. 3.0

We should use economic decisionmaking. 2.9

We should harvest more. 2.9

Management values group mean 3.0

Public values and objectives: Objectives

Improve and protect forests. 4.7

Protect ecosystems for wildlife habitat. 4.6

Preserve forests without timber harvest. 4.2

Preserve wilderness. 4.2

Allow for diverse uses. 4.1

Preserve cultural uses. 3.8

Provide resources to people. 3.6

Public values and objectives group mean 4.2

Source: Shield et al. 2002.

Sidenote 5—Barry Commoner formulated the Four Laws 

of Ecology (Partridge 2000):

 Everything is connected to 

everything else. 

 Everything must go somewhere. 

 Nature knows best. 

 There is no such thing as a free 

lunch.

Arcadianism and the Ecology Movement

In the mid-18th century, Gilbert White, a curate in Selborne, England, founded Arcadianism, advocating a simple, rural life and 

restoring man as part of nature. Ludwig von Bertalanffy later described this view as holism. Through recent Arcadian reactions 

against technology and the scientific paradigm, the ecology movement appeared with spokespersons like Rachel Carson, Paul Sears, 

Barry Commoner (sidenote 5), and James Connell. In 1935, Sears 

defined conservation as restoring biological order, maintaining the 

health of the land and well-being of the Nation, and establishing a 

lasting equilibrium of man with nature (Worster 1990).
12 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Christian Pastoralism, the Imperial View

This philosophy strips nature of all spiritual qualities. Nature’s chief 

function is to serve the needs of man. With the imperial view of 

nature, modern man’s most important end is domination over the 

Earth. An example is Francis Bacon’s man-made paradise based on 

science.

Arcadian Imperialism

This root began in Carl von Linné’s (1707–1778) Systema Naturae, 

the first of a series of tracts on rationalistic religion. Arcadian imperialism stresses the hand of God in nature, nature as cyclically static 

with symphonic precision, and all things for the sake of man—­using 

other species vigorously, eliminating undesirable species, and promoting useful species. Ultimately, the Earth must be managed for 

maximum output. In the Age of Reason, this was the utilitarian 

philosophy.

Thoreau’s Romantic Ecology

Henry Thoreau (1817–1862) was Gilbert White’s inheritor. His view 

was fundamentally ecological, focusing on relations, interdependences, and holism. Thoreau’s purpose was to reconstruct the actual 

condition of where we dwell to that of three centuries ago, in order 

to produce a single interrelated whole arranged by nature in perpetual balance. Thoreau’s major efforts dealt with the phenomenon of 

forest succession—accepting nature as a teacher and accommodating oneself to her rhythms. This return to wilderness redefined man’s 

place in nature. It was also a return to paganism with its fascination 

of the natural world and focus on animism and holism. Thoreau’s 

Romantic ecology produced an ecological perspective—nature as a 

system of necessary relationships that cannot be disturbed without 

changing the equilibrium of the whole.

Darwinian Ecology

Charles Darwin (1809–1882) and his contemporaries, the botanist 

Alexander von Humboldt, the geologist Charles Lyell, and the demographer Thomas Malthus, had a holistic but less harmonious 
C H A P T E R 2 Culture and Conservation 13

view of nature. Humboldt studied the geography of plants, grouping 

species into dominant life forms and in relation to their surrounding 

conditions. He constructed vegetation zones based on relationships 

between altitude, latitude, and vegetation. Darwin studied the severe 

environment of the Galapagos and the different roles assumed by 

various finches, turtles, and lizards. Humboldt and Darwin looked at 

nature comparatively, with a geographical approach, and formulated 

assemblages and systems. Nevertheless, both placed science within a 

larger framework of feeling and sensibility and, in the process, converted their contemporaries from Romanticism to science as religion. Charles Lyell observed the continuing play of natural physical 

forces and the nonpermanence of nature as well as long accumulated 

works of nature and periodic mass extinctions. He studied the fierce 

competition among species for space and food and rejected the Linnaean faith of lasting balance in nature. Thomas Malthus’s essay on 

populations provoked Darwin’s ideas of natural selection of the fittest and evolution of new species. Donald Worster (1994) suggested 

that Darwin’s reading of Malthus’s essay may have been the single 

most important event in the history of Anglo-American ecological 

thought and led to constructing a science to meet one’s own emotional and psychological needs. 

From Ecology to Conservation

Ecology has its roots in White, Linnaeus, Humboldt, Lyell, and 

Darwin. Ernest Haeckel, a disciple of Darwin, coined the term with 

reference to biogeography, and C. Hart Merriam contributed concepts of life zones and habitats. At the turn of the century, Victor 

Shelford called ecology the science of communities, and A.G. Tansley emphasized dynamic ecology and successional development of 

communities. Frederic Clements formulated a coherent and elaborate system of ecological theory, now often inaccurately portrayed 

(see Partridge 2000 for a discussion on how idealized concepts are 

important to science but often discredited through distortion or reductionism). Clements stressed that vegetation is essentially dynamic 

and that succession is not aimless, but a steady flow toward stability 

along a sere with its direction and progression determined by climate. He also introduced the concept of a climax stage based on the 

Spencerian philosophy of cosmic evolution, in which all phenomena 

progress toward differentiation and integration, from homogeneity 

to heterogeneity, and from differentiation to interdependence.

 In the early 1930s, the American Dust Bowl and the economic 
14 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

collapse of stock markets produced a public and scientific willingness to subordinate economics to broader values. This included ecological integrity, as in the conservation philosophy articulated by 

Aldo Leopold: 

The fallacy that economic determinists have tied around our 

collective neck, and which we now need to cast off, is the 

belief that economics determines all land-use. This simply 

is not true. An innumerable host of actions and attitudes 

... is determined by the land-users’ tastes and predilections, 

rather than by his purse (Leopold 1949). 

Leopold continued, “The bulk of all land relations hinges on investments of time, forethought, skill, and faith rather than on investments of cash. As a land-user thinketh, so is he” (Leopold 1949).

At the same time, Leopold was a pastoralist devoted to husbandry: “...two spiritual dangers in not owning a farm ... supposing 

breakfast comes from the grocery store, and ... heat comes from a 

furnace” (Leopold 1949). He described, “... definitions of ... a conservationist ... [are] best ... written not with a pen, but with an axe 

... what a man thinks about while chopping or while deciding what 

to chop” (Leopold 1949). In his 1933 text on game management, 

Leopold wrote: “Effective conservation requires ... deliberate and 

purposeful manipulation...” (Leopold 1933). This philosophy is not 

dissonant. Just as Aldo Leopold harvested a lightning-struck oak 

for firewood two generations ago, contemporary Pacific Northwest 

forest activist, Andy Stahl, harvested his own mature oak to turn 

into cabinetry. One presumes that wilderness advocate John Muir 

had no compunction about burning wood in his wilderness campfires. What is most relevant in choices about using natural resources 

relates to frequency, intensity, scope, and scale of use.

Whereas Leopold focused on restoration of degraded, abandoned farmland in his famous treatise, A Sand County Almanac, his 

contemporaries, ecologists Roger Smith and Paul Sears focused on 

climax grassland communities. They argued that climax communities should be left unmanaged because they are resilient. However, 

the concept of untouched climax communities was antitechnology, 

and botanist Henry Gleason responded with his individualistic concept of plant associations as accidental groupings and repudiating 

succession (later expanded into a grand theory by Hubbell in 2001). 

Gleason described climaxes as haphazard, imperfect, and shifting, 

implying that climax communities were not special and need not 

be protected. Tansley chimed in rebutting monoclimax in favor of 
C H A P T E R 2 Culture and Conservation 15

multiclimaxes (edaphic, biotic, fire, anthropogenic).

Progressive conservation was part of the political movement of 

Teddy Roosevelt. Gifford Pinchot supported doing away with reserves: “Forestry is handling trees so that one crop follows another.” 

Efficiency and productivity were applied to public lands for the first 

time. John Muir opposed Pinchot’s progressive agronomic perspective, as John Grinnell protested Leopold’s predator control. Debate 

on how to integrate ecology into conservation was widespread. Ecological pragmatism sought to preserve natural checks and balances. 

Olaus Murie accepted the need for management but opposed emotional persecution of varmints. 

Leopold’s 1949 description of a land ethic ushered in the Age of 

Ecology by establishing a scientific, ecological, biocentric, and communitarian ethic that challenged the economic ethic. A concept of 

natural rights was derived from the Declaration of Independence. 

The Rights of Nature extended to all species and even to the Earth 

itself. Leopold suggested that unless man recognized the rights of 

the entire Earth, he might find his own survival threatened—“... 

the first principle of conservation: to preserve all parts of the land 

mechanism ...” (Leopold 1949). He emphasized, “To keep every cog 

and wheel is the first precaution of intelligent tinkering” (Leopold 

1949). Aldo Leopold’s philosophy, however, remained agronomic 

even while reconciling rival worldviews. Worster (1994) explains: 

“Every generation writes its own description of the natural order 

which generally reveals as much about human society and its changing concerns as it does about nature.”

In 1927, Charles Elton promulgated the sociology and economics of animals and five principles describing the economy of 

nature: (1) the food webs of producers, consumers, key industries, 

and interdependencies; (2) food size determining organism size; (3) 

pyramids of numbers; (4) the niche as occupation, especially what 

the organism is eating; and (5) competitive exclusion. A few years 

later, G.F. Gause promoted competition as the law of nature, and 

A.G. Tansley disputed synergy and the concept of community and 

favored ecosystems as physical systems of material exchange. In the 

1940s, Ray Lindeman merged the ideas of Elton, Tansley, Chancey 

Juday, and Edgar Transeau into the Trophic-Dynamic Aspect of Ecology, describing the energy pathways (Worster 1994). 

The 1960s “New Ecology” reflected the values of the modern 

economic order—corporate society with interdependence, primacy 

of efficiency and productivity, and a managerial ethos. A new breed 

of mathematical ecologists arose, including G. Evelyn Hutchinson, 

Robert MacArthur, and Eugene P. Odum as the scientists of natural 
16 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 6—The other most 

important publication in biology 

in the 20th century was James 

Watson and Francis Crick’s 1953 

paper on the structure of DNA

(Hardin 1969).

economics. Odum (1969) postulated that all ecosystems have a 

strategy of development directed toward achieving as large and diverse an organizational structure as possible based on mutualism, 

cooperation, and symbiosis, embellishing Clements’ theories. This 

bioeconomic ecology owed a great deal to its larger cultural milieu 

but did not satisfy the communalism of Leopold’s fellowship. 

Then there came about a resurgence of philosophical idealism 

and a quest for transcendence, eternal harmony, and cosmic love. 

James Lovelock and Lynn Margulis wrote the Gaia theory. Rachel 

Carson, Paul Ehrlich, Barry Commoner, and Edward O. Wilson 

perceived an Earth in crisis. Rachel Carson’s Silent Spring was one 

of the two most important publications in biology in the 20th century (Hardin 1969) (sidenote 6). The Ecological Society of America 

issued that Silent Spring “created a tide of opinion which will never 

again allow professional ecologists to remain comfortably aloof from 

public responsibility ... its effect on public opinion, national scientific policy, and ... professional societies ... can hardly be overstated” 

(Hardin 1969). That well-meaning interventions in natural systems 

have caused great and unforeseen harm has the practical implication 

that “we can never do merely one thing” (Hardin 1969). 

In the 1970s and 1980s, the focus of ecology moved to disturbance theory (Connell and Slatyer 1977, Drury and Nisbet 1973, 

Pickett and White 1985b). These “disturbance boosters” were population biologists, not ecosystem scientists, and as such focused on 

trees and not the forest. In doing so, they perceived no synergy and 

no emergent properties (Worster 1990). Constant change and incessant disturbance satisfied them ideologically more than Odum’s 

ecosystem, with its stress on cooperation and social organization. 

Disturbance theory is more consonant with individuality, private 

enterprise, social Darwinism, and the generational transition from 

the politically conscious generation of the 1960s to the yuppie generation of the 1980s. The rise of disturbance theory is a triumph 

of reductive population dynamics over holistic consciousness and 

of social Darwinist entrepreneurial ideology over a commitment 

to environmental preservation. Edward Lorenz developed the scientific study of chaos in 1961, and the promulgation of nature as 

fundamentally erratic was a revolution against all principles, laws, 

models, and applications of classical science (Gleick 1987, Worster 

1990). Robert May discounted the relationship between diversity 

and stability, John Wiens wrote of stochasticity, and Paul Colinvaux 

was antimanagement (Worster 1994). 

This trend continues today—Hubbell (2001) presents a grand 

Unified Neutral Theory of Biodiversity and Biogeography. The wedding 
C H A P T E R 2 Culture and Conservation 17

Figure 1—Regine Carey, the 

author’s wife, leans against an oldgrowth tree in the Hoh Rainforest, 

Olympic National Park. Photo by A. 

Carey.

of evolutionary ecology and population biology produced conservation biologists and the cognitive dissonance they embody—nature is 

a finely tuned watch and every piece is important in a chaotic world 

with each species population being independent and with no emergent properties. The logical consequences of this train of thought 

are profound (Partridge 2000). Why preserve old-growth forests 

(fig. 1) if they are simply haphazard collections of independent species? What constitutes environmental degradation, or even environmental destruction, in a world of disturbance and chaos?

The history of ecology reveals interdependence between scientific thought and values of the contemporary society. Science and 

culture are not independent—science actually follows culture. History documents continuing threads over centuries in how people 

think about their relationship to nature and how science seems to 

spiral upwards cycling among philosophies but always gaining in 

complexity. The recapitulation of Worster’s history only briefly describes the diverse and rapid intellectual and scientific development 

of ecology within the adult lifetime of today’s senior academicians, 

scientists, administrators, and managers active in the conservation 
B

A C

D

18 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 2—Models of enduring 

human communities and their interactions with nature: (A) Maasai boys, on 

the Maasai Mara, prepare for induction into manhood by collecting, without weapons or snares, birds for their 

headdresses. The Maasai are herdsmen, 

and with the Kikuyu farmers and 

other agriculturally specialized ethnic 

groups, they partitioned the landscape 

into ecological zones and developed 

sustainable agronomic practices 

adapted to those zones. Colonization 

reorganized African societies and 

imposed European agricultural models 

on the landscapes with sometimes-disastrous results. (B) A cultural mosaic 

of suburban development, small farms, 

and industrial forest near Olympia, 

Washington. (C) A sustainable cultural 

landscape of farming communities, 

farms, and forest in Germany. Guttau 

was officially founded in 1238; the 

photograph is circa 1985 (from the 

collection of Regine Timm Carey). 

Herr Willi Timm, bauer and jaegermeister, managed the landscape 

for harvestable populations of grains, 

rapeseed, pheasant, partridge, hare, fox, 

roe deer, and red deer. (D) The rapidly 

growing urban area of Olympia, the 

state capitol of Washington, and its 

adjacent cities of Lacey and Tumwater 

(the first area in Washington settled 

by Americans of European ancestry) 

are having increasingly severe impacts 

on the South Puget Sound naturalcultural mosaic of Douglas-fir forest, 

native prairies, oak woodlands, kettle 

wetlands, riparian areas, and salt-water 

shoreline. Photos A, B, and D by A. 

Carey; Photo C courtesy of R. Carey.

arena. Quite contrary to the unspoken philosophy underlying disturbance ecology, Worster (1990, 1994) concludes:

 Nature works by the principle of interdependency—no organism or species can survive without the aid of others, and humans 

depend on other life forms. 

 No single model, but a wealth of models represents nature. History reveals models of enduring human communities that created rules to govern behavior based on intimate local experience 

(fig. 2). Science cannot take the place of moral reasoning, and 

science needs to be critiqued from time to time to avoid its promotion of a few of our darker ambitions toward nature. 

 Change is not only real but also various. Some changes work 

against us. Some changes are in our own enlightened self-interest, and some are consistent with our ethical reasoning. 

 We can no longer locate nature in some timeless state of perfection.

Partridge (2000), in an independent analysis, drew similar conclusions. Odum (1969), Holling (1994, 2001), and other systems theorists also support this markedly different view of the world.
C H A P T E R 2 Culture and Conservation 19

Sidenote 7—Czech et al. 

(2001) found gender influences 

conservation attitudes. Women 

ascribe greater value to nonhuman species than men and 

exhibit greater concern for species 

conservation relative to property 

rights. But like men, they consider 

ecological importance as the most 

important factor in prioritizing 

conservation efforts for individual 

species. Priority percentages—female/male (N = 643):

 Economic growth—74/76

 Democracy—82/83

 Property rights—75/77

 Ecosystem health—84/79

 Conservation of species—

80/75

 Resources for the future—

88/85

Contemporary Themes in Conservation

Our society supports multiple concurrent and overlapping themes 

in conservation. Most are overtly value laden (Callicott et al. 1999). 

Americans are moving from environmental beliefs and values based 

on technology to those based on ecology and human relations; 75

percent consider themselves to be environmentalists (McDonough 

2003). One broad theme is a general social concern for quality of 

life relative to the environment in which we live (see also Czech et 

al. 2001, Ehrenfeld 2002) (sidenote 7). Environmentalism includes 

concerns about clean water, clean air, industrial pollutants, automobile emissions, home contaminants, food preservatives, toxic waste 

dumps, global warming, open space, wastewater treatment, watersheds, parks, and all other things potentially affecting human health 

and quality of life, such as oil drilling, mining, extensive clearcutting, 

use of chemicals in forestry and agriculture, tropical deforestation, 

desertification, destruction of major fisheries, and global loss of biodiversity. Ecosystem health is the public value considered by many 

to be a useful, perhaps essential, concept in formulating environmental policy; the concept reflects value-based assumptions more 

than science (Lackey 2001). Thus, broad-based anthropocentric environmentalism may have real influences on conservation of natural 

resources. 

Although there is growing public concern, environmental issues are nearly absent from national political campaigns and rarely 

shape individual voter preferences because of low issue salience, 

small perceived differences between candidates, and the tendency of 

environmental concerns to cut across traditional and more powerful cleavages including political party identification (Guber 2001). 

Thus, legislature has been scaling back wildlife protection and pollution control since 1994, despite the National Election Study that 

confirmed environmental values (Guber 2001). Because of low voter 

interest and low levels of political knowledge and information, most 

voters fail to perceive party differences, even on important matters of public policy. Bengston et al. (2001) examined 1,500 online 

media stories and concluded that ecosystem management (and, 

one presumes, conservation) is on the downside of the attention 

cycle. Interest rose in the early 1990s, declined in the mid-1990s, 

and leveled out with 78 percent of all attitudes favorable (in other 

words, ecosystem management was noncontroversial); but still most 

people have little or no knowledge of ecosystem management, including the concepts of ecosystem health, conservation of biodiversity, sustainability, complex systems, adaptive management, or 
20 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 8—Kellert et al. 

(2000) reported that community 

forest management is extensively promoted for ecological, 

social, and economic reasons. The 

rationale is often compelling, but 

there is little data on its success. 

A review of five case studies worldwide revealed serious, 

widespread deficiencies based on 

criteria of equity, empowerment, 

conflict resolution, knowledge and 

awareness, biodiversity protection, 

and sustainable resource use. The 

ideal characteristics of community 

forest management are:

 Involving community members and local and indigenous 

institutions in management

 Devolving power and authority from central to more local 

and indigenous institutions 

and people

 Reconciling objectives of 

socioeconomic development, 

conservation, and environmental protection

 Legitimizing local or indigenous resource and property 

rights

 Including traditional values 

and ecological knowledge in 

modern resource management

collaborative management (Bengston et al. 2001). Television entertainment shows decreasing attention to environmental topics since 

a peak in 1993–1994, with a virtual absence of the topic on prime 

time network shows (McComas et al. 2001).

The lack of national public interest, the concentration of forest 

products manufacturing in fewer multinational corporations controlling larger areas of forest, the lower commitment of absentee 

owners to community stability, and the lack of commitment of multinational corporations to long-term maintenance of forested ecosystems or mill communities and their employees led Krogman and 

Beckley (2002) to suggest community forestry and demands for socially and ecologically responsible forest management as alternatives 

to corporate forestry (sidenote 8). Community forestry is a situation where community benefits are enhanced relative to standard 

industrial forest models and can be achieved through value-added 

investments in communities and progressive local hiring policies. A 

broad spectrum of value-added investment types is possible: school 

forests, urban forests, county and municipal forests, forestry cooperatives, model forests, and others devoted to local control and local 

benefit. Buyout of corporate lands can lead to increased community 

cohesion through maintaining employment and fair and congenial 

working conditions by the new owner. Heightened sensitivity to 

ecosystem health and provision of multiple benefits to communities 

provide greater ecological stewardship of forest land. Alternatively, 

communities can participate in collaborative management of federal, state, industrial, and private land by using a variety of tools and 

mechanisms, including tax benefits, conservation easements, forest 

stewardship certification in the market place, and others.

Within the arena of conservation of forests and rangelands, Callicott et al. (1999) found a plethora of normative concepts including 

biological diversity, biological integrity, ecological restoration, ecological services, ecological rehabilitation, ecological sustainability, 

sustainable development, ecosystem health, ecosystem management, 

adaptive management, and many more. They suggested that these 

terms, with their various meanings, could be interpreted by reference to two new schools of conservation philosophy: compositionalism and functionalism (table 2). In contrast to previous schools 

of preservationism and resourcism, which were mutually exclusive, 

compositionalism and functionalism are complementary, forming a 

continuum, and could lead to a more unified philosophy of conservation. Although some remain skeptical, Callicott et al. (1999) asserted “these concepts are at large in the world shaping conservation 

thought and policy.”
C H A P T E R 2 Culture and Conservation 21

Table 2—Differences between contemporary conservation philosophies

Philosophy Compositionalism Functionalism

Human-nature relationship 	Humans are separate from nature; 

humans defile and destroy nature

	Humans are part of and embedded 

in nature

Branch of ecology 	Evolutionary ecology

 Organisms

 Species

 Communities

 Ecosystems

	Ecosystem ecology

 Energy flow

 Nutrient cycling

 Processes

 Function

Complementary approaches to conservation

Conservation concepts 	Preservation of:

 Biological diversity 

 Ecological integrity

	Ecological restoration

	Reserves

	Ecosystem health

	Ecological services

	Adaptive management

 Ecosystem management

 Sustainability

 

Source: Adapted from Callicott et al. 1999.

Compositionalism

Compositionalists perceive nature primarily through populationlevel and evolutionary ecology and consider humans as separate 

from nature. Terms in a compositionalist glossary, such as biodiversity, integrity, and restoration, are norms associated with reserves. 

Compositionalism is essentially an entity-oriented biological approach—beginning with organisms that are aggregated into populations, which interact in biotic communities in maintained reserves. 

Emphasis is often on identifying areas of high species richness and 

preserving them (e.g., Ricketts et al. 1999). Protection of hotspots of 

biodiversity is appealing because it does not require changes in our 

daily living or the way we behave toward poorer nations and the other 99 percent of the land (Ehrenfeld 2002). Humanly inhabited and 

exploited areas are relegated to the functionalists. Compositionalists 

posit all species have equal rights to persist in nature; productivity, 

stability, resistance, and resilience in nature are partly a function of 

species diversity, functional redundancy, and niche differentiation; 

and the consequences of losing any one species or groups of species 

are not predictable and could be disastrous. They assert that reliance 

on isolated reserves in a semideveloped matrix is inadequate to stem 

the tide of an unprecedented wave of extinctions arising from habitat conversion by rapidly expanding human populations. Compositionalists support large, buffered, and connected reserves and deem 

a return to historical disturbance regimes as vital. Buffer zones are 
22 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

necessary because “... it is impossible to secure enough public land 

to protect all biodiversity” (Soulé and Terborgh 1999).

Functionalism

Functionalists perceive nature primarily by means of ecosystemlevel ecology and consider humans as part of nature. Terms in the 

functionalist glossary are associated with humanly inhabited and 

exploited areas. Functionalism is a process-oriented approach—beginning with solar energy and the physical system with biotic organisms as moments in interlocked processes of energy transfers 

and nutrient cycles, indifferent to specific taxonomic identity. Functionalists postulate there is little evidence that a particular number 

of species is required for any particular ecosystem function or that 

ecosystems function better with more species than with fewer; if 

abundance or diversity of a particular functional group changes, it 

suggests the ecosystem has changed relative to that function; and 

maintaining ecosystem function through the presence and vitality 

of functional groups is more practical than attempting to maintain 

a large number of species without regard to their function (Huston 

et al. 1999).

A Fusion of Complementary Approaches

Can compositionalism and functionalism be used to form an integrated coherent approach to managing the total landscape? Conservation of biodiversity is more feasible when its goal is not conflated 

with that of wilderness preservation (Sarkar 1999). Aldo Leopold 

wrote, “Ability to see the cultural value of wilderness boils down 

[to] ... intellectual humility,” and moreover, we need “... a militant 

minority of wilderness-minded citizens ... available for action” to 

ensure wilderness preservation (Leopold 1949). However, Leopold 

also believed that healthy ecosystems can incorporate human inhabitants, economic exploitation, and management, and that “there are 

degrees and kinds of solitude” (Leopold 1949). 

The current battle over ecological dogma is distressing (Callicott et al. 1999, Hardin 1969). For example, claims that landscapes 

unaltered by humans existed in North America at the arrival of Europeans are often (not always) fallacious—the Europeans’ diseases 

preceded their explorations, decimating indigenous populations and 

obscuring evidence of the aboriginal influence on the landscapes 
C H A P T E R 2 Culture and Conservation 23

Annette Wilson hikes along an oldgrowth forest trail in the Olympic 

National Forest, near Quinault, Washington. Photo by T. Wilson.

(Krech 1999, Pyne 1997, Reid 1996, Wright 1992). The long history 

of human interactions with nature reveals that landscapes that have 

not experienced important human influences are the exception. 

Wright (1992) described the civilizations of the Iroquois, Cherokee, 

Aztec, Maya, and Inca in the Americas. The history of agriculture 

and technological development in agriculture has been documented 

in Europe, too—e.g., the Ystad Project in Sweden (Malmer 1991). 

Ystad documents human land use to 6,000 years ago by pre-Neolithic hunters and gatherers, herding and slash-and-burn agriculture 

3,000 to 5,000 years ago in the Neolithic Bronze Age, permanent 

field farms 1,000 to 3,000 years ago in the Iron Age, advanced field 

farming 500 years ago, and artificial fertilizer farming in the present 

(Berglund 1991). 

Information on aboriginal interactions with the biophysical environments of the Americas now abounds. Aboriginal overkill eliminated 31 genera of North American mammals 11,000 to

17,000 years ago (Martin 1973). Humans in Mesoamerica practiced 
24 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

intensive agriculture well before the Europeans adopted this practice 

(Wright 1992). The Spanish reintroduced the horse to the Americas 

500 years ago, and the horse quickly became widespread and domesticated by indigenous peoples. An estimated 400,000 horses were 

grazing the prairies of eastern Washington when Lewis and Clark 

arrived. There was ample evidence of a long history of prescribed 

burning to maintain prairies, oak woodlands, and shrubland-conifer 

savannahs in western Washington and Oregon when settlers from 

the Eastern United States first arrived (Thysell and Carey 2001b). 

Thus, conservation strategies minimizing human intervention may 

fail because the objective of maintaining a natural ecosystem may be 

nonsensical or oxymoronic—excluding human influence is not natural (Reid 1996). Moreover, conservation is almost never the preservation of primeval conditions, but rather a means of maintaining 

critical functions of the primeval system (Allen et al. 2001) and its 

capacity to adapt to future change (Holling 1986). 

Nevertheless, one cannot simply maintain or restore ecological processes and conserve biodiversity—some such processes are 

generic and can be performed by weedy species (Soulé 1986). Most 

conservationists are somewhat in the middle of the compositionalist-functionalist continuum, and many shift back and forth in emphasis depending on circumstances. The keystone species concept 

provides a nexus of evolutionary and ecosystem ecology (Callicott 

et al. 1999). The goal of evolutionary ecology is to explain and predict the behavior of individual organisms and populations because 

natural selection acts exclusively on individuals. The trophic structure of biotic communities, then, should be accounted for by the 

exclusive application of evolutionary theory. However, evolutionary 

ecologists studying the dynamics of populations and communities 

have found foraging behavior and life histories depend on ecosystem characteristics as well as interactions with other species populations. Because ecological processes occur at discrete temporal scales, 

they create discrete scales in space (landscapes composed of patches 

composed of microhabitats). For example, the ecological process 

of competition between northern flying squirrels and Townsend’s 

chipmunks (see appendix for scientific names) for the same truffles 

occur at very local scales where both species are present. This might 

be a shrub patch within a forest, or in other words, a microhabitat 

within a patch within a landscape. Other processes, particularly hydrologic processes like waterflow, may occur at much larger scales, 

such as landscapes (watersheds) within multiple landscapes. Ecosystem ecologists have found efforts to model and predict some ecosystem functions are foiled because species do matter. Community 
C H A P T E R 2 Culture and Conservation 25

ecologists must fuse the ecosystem and evolutionary approaches to 

ecology in order to predict accurately the impact of particular species on particular food webs, key biotic communities, or to predict 

the outcome of human development projects. Thus, a synthesis already is underway. This synthesis of paradigms is necessary for the 

development of conservation strategies that integrate reserves and 

other protected areas with the rest of the biosphere. 

Callicott et al. (1999) concluded that emphasis on preservation 

of biodiversity and ecological restoration is appropriate for wilderness areas, wildlife refuges, national and state parks, world heritage 

sites, and international biosphere reserves. This list is somewhat 

problematic in that many wildlife refuges are intensively managed 

with agricultural crops to provide concentrated food supplies for 

migratory wildlife, and parks often explicitly were set aside legislatively for human enjoyment and edification, which are not necessarily incompatible with maintenance of biodiversity but are perceived 

as such by many. Co-opting parks and refuges to meet extreme philosophical tenets would exacerbate divisions among conservationists 

rather than reconcile differences. Callicott et al. (1999) suggested 

that the functionalist emphasis on ecosystem health, ecological services, adaptive ecosystem management, and ecological sustainability, 

is more suited to inhabited and exploited areas than to reserves. 

They state: “The really innovative idea in contemporary conservation is the functionalist ideal, which conceives of human economics 

as embedded in the larger and more enduring economy of nature.”

The point is to adapt human economics to ecological exigencies in order to achieve a mutually sustaining relationship between 

humans and the ecosystems they inhabit and on which they clearly 

depend; however, Wilber (1995) would argue the embedment is in 

the opposite direction. Of course, the really exciting idea is social 

evolution with its best end products being lasting institutions, durable friendships, stable communities, accumulated wisdom, and 

gentle and productive cooperation that promote local conservation 

with continuity, passed from parent to child and friend to friend 

(Ehrenfeld 2002).

Conservation, Forest Management, and 

Sustainability

The science of ecology has had a popular impact unlike that of any 

other science; it has been ubiquitous, and it has changed the language of politics and philosophy (Worster 1990). Concerns about 
26 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

forest conservation and sustainability are producing ecological forest 

management systems across the biosphere (e.g., Hunter 1999, Larson and Danell 2001, Mönkkönen 1999, Swedish National Board of 

Forestry 1990, Virolainen et al. 2001, Wikstrom and Eriksson 2000, 

Yang 1997). Trees and forests are important to Americans for their 

ecological contributions and their economic value ($200 billion/

year). But the ecological contributions are more valued by a culture concerned with aesthetic qualities, pollution, and sustainability; 

changing values are reflected in the growing dichotomy between 

commodity-focus forestry and environmental and restoration management (McDonough 2003). Sustainability is a word that evokes 

positive associations and that is claimed and shaped by proponents of 

various conservation philosophies to their own goals. Pacific Northwest neo-conservation biologists argue that achieving sustainability 

(meeting human needs without compromising the health of the ecosystem) should be the principal goal of conservation, whereas orthodox conservation biologists do not welcome a paradigm shift from 

wilderness to sustainability (Callicott and Mumford 1997). Ecosystem management is often held as the means to achieve environmental sustainability in managed forests. Ecosystem management asks 

forest stewards to manage lands for commodities, amenities, and 

native biological diversity. Ecosystem management, however, can 

conflict with commodity interests, wilderness advocates, and outdoor recreationists; this term also is co-opted by narrow interests to 

legitimize narrow goals (Knight 1996).

Forestry and Conservation

Concern about a global biodiversity crisis arose in the late 1970s 

(Noss and Kranz 2001, Wilson 1999a). By 1993, more than 600 

species had been listed as threatened or endangered in the United 

States. The Endangered Species Act of 1973 has had less effect than 

expected because remedial action is not triggered until a population is in serious trouble (Orians 1993). And federal agencies, first 

in a state of “future shock,” then “midlife crisis,” failed to adapt to 

rapidly changing societal demands (Bengston 1994, Kennedy and 

Quigley 1998). R.E. Wolf, a key congressional staff member for important federal conservation legislation (Multiple Use Sustained 

Yield Act, Wilderness Act, Resources Planning Act, and National 

Forest Management Act) labeled USDA Forest Service behavior as 

a “corruption of the Resources Planning Act” (Wolf 1989) (table 3). 

The new environmental paradigm was environmental sustainability, 
C H A P T E R 2 Culture and Conservation 27

Table 3—Traditional forest management versus ecosystem management

Traditional forest management Ecosystem management

	Maximize commodities

 Maximize net present value

 Sustained yield

 Forest management as an applied science

 Instrumental values

 Focus on outputs

 Timber focus

 Timber in short supply

 Reductionistic view

 Stand-level focus

 Plan and manage by ownership

 Economic efficiency

	Leopold land ethic and sustainable commodity 

production

	Maintain future options

 Long-term ecosystem sustainability, maintaining 

aesthetics, socially acceptable

 Forest management as a social science

 Instrumental and intrinsic values

 Focus on inputs and processes

 Species focus

 Loss of biodiversity

 Systems view

 Ecosystem-landscape-level focus

 Plan and manage by ecosystem

 Cost effectiveness and social acceptability

Source: Adapted from Bengston 1994.

skepticism of science and technology, finite natural resources, limits to substitution, and public involvement (Bengston 1994). Classic 

forestry concepts of multiple use and sustained yield were not useful to contemporary, ecologically informed, biocentric conservation 

(Callicott and Mumford 1997). The Forest Service was a model machine bureaucracy, but complex, challenging, and important policy 

issues are ill served by command-and-control paradigms (Lackey 

2003). 

In the Pacific Northwest and Alaska, the diverse high values of 

forests have intensified conflict, and the public has become more 

polarized and distrustful; the polarization is manifested in Forest 

Service alternatives of zoning for different uses and attempting to 

identify compatibilities between wood production and other values 

(Peterson and Monserud 2002). Command-and-control paradigms 

not only polarize the public, but also engender top-down centralized decisionmaking and attendant public resistance, rarely use new 

scientific and technical information, and reinforce policy and scientific reductionism (Lackey 2003), yet such policies based on these 

paradigms persist (Mills et al. 2002) (sidenote 9). Kimmins (2002) 

reported similar future shock in forestry in Canada (sidenote 10). 

Perry (1998) defined forestry as the scientific management of 

forests for continuous production of goods and services, but cited the 

National Research Council as concluding that existing knowledge 

was inadequate for sound forest management in 1990. Perry (1998), 

and many others, concluded that the social sciences, including sociology, aesthetics, ethics, spirituality, economics, history, and so on, 
28 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 9—Achieving 

science-based national forest 

management (Mills et al. 2002):

 Decisionmakers (line officers) 

and the public fully appreciate 

the contributions of science to 

land management.

 Forest Service scientists and 

professionals provide the science needed for decisions.

 Policy-relevant science is readily available and easy to use.

 Available science is fully used 

by decisionmakers.

 The consistency of land management with available science 

is evaluated.

 Science is recognized as important but only as one piece 

of information considered in a 

decision.

Sidenote 10—Kimmins 

(2002) defined future shock as the 

point at which the rate of change 

in society exceeds the willingness and ability for institutions to 

adapt to change.

are critical to forest management. Furthermore, as Kimmins (2002) 

stated, forestry is about people—their needs and desires—not fundamentally about biophysical issues. At present, North American 

forestry seems archaic and too narrowly focused to conduct forest 

ecosystem management. 

Technical ecosystem management is broadly interdisciplinary, 

requiring specialists in forest ecology, plant ecology, silviculture, forest insects and diseases, wildlife, biodiversity, geology, forest engineering, and on and on. The forestry profession is in trouble because 

of resistance to change and maintaining an archaic forestry dogma 

including the economic myth of soil rent theory and short rotations 

(Curtis and Carey 1996, Maser 1994). Soil rent theory has six flawed 

primary assumptions (Maser 1994): (1) the depth and fertility of soil 

is constant, (2) the quantity and quality of precipitation is constant, 

(3) the quality of air is constant, (4) biological and genetic diversity 

are nonessential, (5) the amount and quality of solar radiation are 

constant, and (6) climate is constant. 

Overarching the technical aspects of ecosystem management 

is social forestry, the science of sustainable forest management for 

multiple values—a new environmental management that needs to 

develop and use credible, ecologically based forest ecosystem management models based on both experience and theoretical models (Kimmins 2002). Administrative and legal challenges to forest 

management in the United States convinced Jack Ward Thomas 

(Chief of the U.S. Forest Service, 1993–1996) in 1996 that “... the 

overriding de facto policy for the management of federal lands is the 

protection of biodiversity” (MacCleery and Le Master 1999). Huge 

areas of federal land were allocated to reserves that permit little or 

no active management under the assumption that natural regulation 

will maintain a natural balance. Since then, timber sales on national 

forests have dropped 70 percent (since a 1985 benchmark), and 23 

percent of the forests (about 17 million hectares or roughly the size 

of Washington state) have been set aside. Nationwide, in 1999, only 

35 percent of total land holdings (48 percent of productive forest 

lands) in the National Forest System and 15 percent of land holdings in the Pacific Northwest were available for timber harvests. 

Rangelands have been subject to the same pressures for conservation, and grazing on federal lands is beginning to decrease (Davis 

2001, Samson and Knopf 2001). 

Narrow-focus forestry wrought profound changes on other continents also. For example, forestry in Fennoscandian forests began in 

the 1700s; numerous species were red-listed in the 20th century. In 

the 1990s, Nordic countries implemented forest conservation efforts 
Values in existence—social, culture, 

historical, and geographical relations

Social process

Debate

Dialogue

Negotiation

Norms

Values

Ethics

Morals

Principles

Values

Beliefs

Influence

Inform

Motives

Attitude

Preferences

Actions

Behaviors

Choices

Conduct

Influence

Affect

Experiences

Interests

Perceptions

Feelings

Thoughts

New thoughts

C H A P T E R 2 Culture and Conservation 29

Figure 3—Schematic representation of value formation: Thus, values 

can shift, be contested, be multiple and 

renegotiated, be reviewed, and be reinterpreted through discursive processes, 

or revised meanings and understandings (O’Brien 2003).

Sidenote 11—Management 

for Multiple Values (O’Brien 

2003): Forests should be managed 

for multiple values rather than 

multiple uses. Instead of focusing on the forest as a resource to 

be used, managing for multiple 

values posits that respect is given 

to human and forest communities in order to provide a wide 

range of benefits. Management 

for multiple values highlights 

the ethical dimension of management, incorporates moral 

judgments, and brings together 

different interests and expertise. 

Values are (1) formed out of a 

social process of dialogue and 

debate; (2) influenced by social, 

cultural, historical, and geographic 

relationships between society and 

the individual; and (3) informed 

by ethical and moral judgments.

of mimicking natural disturbance regimes, setting aside reserves, and 

implementing a corridor-and-stepping-stone strategy (Mönkkönen 

1999). Now, however, conservation goals are becoming more elusive. O’Brien (2003) assessed people’s values and their importance 

to forestry in England through a review of the literature. He found 

that the values people hold for the environments are multiple and 

complex and produce conflicts when not considered by managers. 

The English public is increasingly interested in having their views 

heard, being involved, and being consulted on environmental matters. Dominant themes are lack of trust in elected representatives, 

feelings of powerlessness in the face of globalization, ethical and 

social impacts of increased technology, and a call for justice in environmental decisionmaking; issues very similar to North American 

issues. He concluded forests should be managed for multiple values 

not multiple uses (sidenote 11) (fig. 3). Values, however, must be assessed through mechanisms like citizen juries, focus groups, indepth 

interviews, and collaborative management. During a tour of restoration projects in Denmark, Sweden, and Germany in 2001, Danish 

and German foresters defined forestry as a social science, with values assessment and collaborative management beginning with oneon-one tea sessions and culminating in community meetings.

Reserves and Conservation

Modern conservation philosophy now questions the concept of 

“protected area” as a throwback to equilibrium ecology. Twenty 

years of emphasis on protected area systems is now suspect on the 

bases of minimum viable population analyses demonstrating the 
30 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

inadequacy of many protected areas and of climate change bringing 

about ecological change (Reid 1996). There is growing consensus 

that management of nonreserved lands is as important for conservation, if not more so, than maintaining a patchwork of reserves and 

corridors (Carey et al. 1999c, Hunter 1999, Reid 1996). A concept 

of “total landscape management” is emerging that incorporates an 

intentional approach including designating wilderness and parks; 

protecting fragile areas; promoting ecological forest management; 

providing tax incentives, conservation easements, and green certification to private landowners; assessing development fees; and 

growth (of socioeconomic systems) management.

New Conservation Objectives

The very objectives of conservation have become more elusive in 

recent years (Reid 1996). What should the overarching concern be? 

The majority of efforts to preserve biodiversity have focused on species, subspecies, and populations. It is fundamentally impossible to 

deal with more than a small fraction of nature on a single-species 

basis. A 1997 symposium on global conservation of mammals asked, 

“Has the panda had its day?” (Entwistle and Dunstone 2000) and 

concluded that success of single-species approaches has not been 

great, that one-quarter of all mammals are threatened with extinction, despite the aesthetic, scientific, and economic values people 

place on mammals. They suggest conservation must rapidly move 

away from protectionism to integrated wildlife and landscape conservation within the context of human use. Moving beyond reserves 

and corridors and managing for ecosystems and landscapes is the 

only comprehensive way to address conservation (Franklin 1993b). 

Some fundamental concern is needed that guides the relationship 

between humanity and nature that addresses our acknowledgment 

that the biosphere’s capacity to support life must be maintained 

(Reid 1996). 

Increasingly, that concern is seen as maintaining biotic integrity and ecosystem health (Regier 1993). The notion of ecological 

integrity is rooted in the integration of ecological concepts with human values. The emergent normative goal of human-environmental relationships, then, is to maintain the integrity of a combined 

natural-cultural ecosystem through ecological understanding and 

an ethic that seeks proper relationships. The concept of ecosystem 

health, however, is more contentious because achieving such an 

overarching ecological objective may fail because of unpredictability 
Find

meaning in

existence

Self-fulfillment

Symmetry, order, beauty

To be curious, understand, explore

Esteem needs: achieve, gain, approval

Belonging and love needs: acceptance, attention

Safety needs: feel secure, seek pleasure, avoid pain

Physiological needs: hunger, thirst, homeostasis

C H A P T E R 2 Culture and Conservation 31

Figure 4—Maslow’s hierarchy of 

human needs (adapted from Maslow 

1987).

Sidenote 12—Ecological 

services are economically valuable, 

diverse, and marginally marketable. Costanza et al. (1997) listed 

the value of 17 ecosystem services 

in 16 biomes around the world at 

an average of $33 trillion per year. 

Krieger (2001) estimated the value 

of forest ecosystem services—climate regulation, waste treatment, 

and food—to be $64 million per 

year in the United States alone. 

De Groot et al. (2002) listed 23

different ecosystem functions—

natural processes that provide 

goods and services that directly 

or indirectly satisfy human needs. 

Eight categories of ecosystem 

services are soil stabilization and 

erosion control, air quality, climate 

regulation, carbon sequestration, biodiversity, recreation and 

tourism, nontimber products, and 

cultural values (Krieger 2001).

of ecological systems and ignorance of those aspects of system behavior that are predictable (Reid 1996). We clearly want to maintain 

ecological services important to humanity, and we want to maintain 

biodiversity to keep options open for future generations (sidenote 

12). Reid (1996) suggested that the objective of conservation should 

not be ecological but social—e.g., maximize human capacity and the 

capacity of the biosphere to adapt to change. 

Of course, all human choices, from designation of reserves to 

urbanization, serve human objectives. Designating reserves enhances self-esteem through perceived altruism and peer positive 

reinforcement. Urbanization buffers people from the more unpredictable whims of nature. Perhaps the most practical goal would 

be to buffer people from the fear of loss of control over one’s life 

promoted by rapid and socially destabilizing technological and environmental developments, while maintaining options for future generations. Maslow’s (1987) hierarchy of needs (fig. 4) provides insight 

into the fundamental bases of conservation-utilization philosophies, 

ties attitudes to economic or security status and self-actualization, 

and highlights intragenerational equity. Three major ecologies must 

be integrated for a sustainable resolution of contemporary conservation concerns and conflicts: (1) an environmental ecology that is 

sustainable, (2) a social ecology that is satisfying, and (3) a spiritual 

ecology that is soulful (Elgin and LeDrew 1997).
32 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

General Sustainability

It is widely recognized that forests should be managed for 

sustainability (Daily and Ehrlich 1996, Dasgupta et al. 2000, di Castri 2000). The concept of sustainable forestry dates from 18th-century concerns about soil productivity (Farrell et al. 2000, Hilborn et 

al. 1995). A broader concept of sustainability derives from John Stuart Mill, Thomas Malthus, Paul Ehrlich, Garrett Hardin, and Herman Daly. In 1981, the International Union for the Conservation 

of Nature and Natural Resources produced a World Conservation 

Strategy and called for ecologically sound use of natural resources. 

In 1987, the World Commission on Environment and Development 

adopted the idea that economic development and environmental 

protection are compatible and called for sustainable development 

of Third-World countries. In 1992, the United Nations Conference 

on the Environment and Development adopted sustainability and 

elicited widespread acceptance by governments. After these events, 

however, sustainability was subordinated to development, supported 

by economists, and opposed by humanists and ecologists (Clark 

1995). The reason for this schism, Nelson (1995) reported, is that 

economics is not only a science, but also a set of values often at 

odds with other natural and physical sciences. Economics is a social science concerned about the interactions and welfare of people. 

Animals, plants, the physical state of the world, and other material 

conditions do not enter into considerations—only what people do 

counts. Emphasis on development promoted fears about overexploitation because history demonstrates universal overexploitation 

in development of natural resources (Hilborn et al. 1995). A new 

discipline of ecological economics arose to address these concerns. 

But as in other conservation disciplines, conflicting values implicit 

in mainstream economics and in ecological economics reflect deep 

underlying theological differences. And both theoretical economists 

(Nelson 1995) and theoretical ecologists (Clark 1995) are too abstract-thinking to produce ideas of practical consequence for policy 

decisions or intellectual generalizations to inform policy well. What 

is actually delivered is metaphysics, morals, personal convictions, 

and, in some cases, religion.

The debate over values pertinent to sustainability produced 

the concept of general sustainability (Goodland 1995). General 

sustainability has three components: environmental sustainability, 

social sustainability, and economic sustainability. Environmental 

sustainability seeks to improve human welfare by protecting sources 

of raw materials (the natural capital) and ensuring that sinks for 
C H A P T E R 2 Culture and Conservation 33

Figure 5—The rich environment of 

the central African highlands supports 

a rich flora and fauna. In Rwanda, 

over 95 percent of the arable land has 

been developed for agriculture. Strong 

international efforts have been made 

to develop economic diversification 

through ecotourism geared around 

reserves for mountain gorillas (Parc 

National des Volcans) and other 

primates (Forêt de Nyungwe). Large 

human populations and colonialism 

induced social inequity between the 

Hutu and Tutsi ethnic groups and 

resulted in genocide. Photo courtesy of 

Rwanda Tourism.

human waste are not exceeded. To be sustainable, harvest rates of renewable resources must 

stay within regeneration rates and not diminish 

the capacity of the environment as a sink. Conservation of biodiversity is generally accepted as 

part of environmental sustainability, but there is 

no agreement on how much and at what cost. 

In any case, people must live within limitations 

imposed by the biophysical environment and 

the finite capacities of the global support system. 

Social sustainability is achieved by systematic 

community participation and strong civil society. The cohesion and norms of a civil society are 

social capital and moral capital. Human capital 

must be maintained by investments in education, 

health, and nutrition. Economic sustainability 

is keeping capital intact. Together these form a 

general sustainability that maintains the life support systems of the atmosphere, water, soil, and 

environmental services. General sustainability 

also has a strong component of both intragenerational and intergenerational equity. Thus, general 

sustainability includes poverty reduction through 

qualitative development, redistribution of wealth, 

sharing of resources, population stability, and community solidarity, but not through increased consumption of materials and energy from the environment, returned to the environment as waste. 

Morally undesirable gross inequities throughout the world are also 

biophysically unsustainable. Thus, to perpetuate poverty has deleterious, irreversible impacts on the biophysical component of Earth’s 

life support system. Poverty around the world has long been associated with dense populations, deforestation, unconstrained mining, 

erosion, desertification, poor farming practices, overgrazing of livestock, and pollution (lack of sanitation systems, polluting factories 

based on cheap labor, etc.). These inequities also hinder cooperation 

among parties of different socioeconomic status (Daily and Ehrlich 

1996). Thus, in essence, sustainability is a normative paradigm for 

improving the quality of human life within the carrying capacity 

of the ecosystem without compromising the ability of future generations to meet their needs. Sustainability is a global concern with 

enormous social and political ramifications if it is to be achieved. Of 

course, the ramifications of not achieving sustainability are equally 

enormous (fig. 5).
34 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

In 1994, Albert A. Bartlett hypothesized that the population of 

the Earth had exceeded the Earth’s carrying capacity for the average 

standard of living and proposed Bartlett’s Laws for Sustainability 

(Goodland 1995):

 Growth in human populations or in rates of consumption cannot be sustained.

 The larger the population and rates of consumption, the more 

difficult the transition to sustainability.

 About 50 years are required for populations to respond to a 

change in total fertility.

 Carrying capacity and sustainable mean standard of living are 

inversely related.

 Sustainability requires population size be less than carrying capacity for a given standard of living.

 Beneficiaries of growth are few, but costs are borne by all (the 

tragedy of the commons).

 Growth in consumption of nonrenewables dramatically decreases their life expectancies.

 Increases in efficiency of utilization produces savings wiped out 

by modest population increases.

 Rates of pollution greater than natural cleansing capacity mean 

it is easier to pollute than clean up.

 Humans always will depend on agriculture and forestry; land 

and renewables always will be essential.

Increased population size is the single greatest and most insidious threat to representative democracy, general sustainability, 

and conservation. Reserving land for nonhuman species limits the 

amount of land available to support people. And the current production is exhausting natural capital. Depletion of essential resources and degradation of land and atmosphere are seriously damaging 

the biosphere and its future biophysical carrying capacity for people. 

Faith in the ability of technology to solve humanity’s problems, paralleled by polarization by extreme statements intended to dramatize, 

make it difficult to “paint a richer picture” and achieve consensus 

on appropriate courses of action (Costanza et al. 2000). Still, there 

are guiding principles for managing the environmental portfolio: (1) 

protect capital, live off interest; (2) hedge investments, do not put all 

eggs in one basket; (3) do not risk more than you can afford to lose; 

and (4) buy insurance—do not harvest everywhere and not even 

close to the sustainable limit.

Policies of diverse organizations, from the USDA Forest Service 
C H A P T E R 2 Culture and Conservation 35

to the nongovernmental Forest Stewardship Council and Pacific Forest Trust to the professional Ecological Society of America 

(Christensen et al. 1996) and industrial American Forest and Paper Association (Heissenbuttel 1996), emphasize that sustainable 

ecosystems are essential to the health and support of human societies and quality of life. Although carefully crafted definitions of 

sustainability have been offered (Goodland 1995), none have received 

universal acceptance. The concept, like other conservation concepts, 

means different things to different people (Clark 1995, Goodland 

1995, Gowdy 2000, Hunter 1999, Lindenmayer et al. 2000, Nelson 

1995, Reid and Miller 1989, Wilson 1999a). Emphasis varies among 

sustained yield of wood products, maintenance of long-term site 

productivity, intergenerational equity, social justice, and conservation of biological diversity (Angermeier and Karr 1994, Christensen 

et al. 1996, Hunter 1999, Soulé and Terborgh 1999). Disagreements 

include debates about (1) limits to economic and human population 

growth (Barrett and Odum 2000, Czech 2000, Davidson 2000), (2) 

the relationship of biodiversity to ecosystem stability (Tilman 1996, 

1999; Wardle et al. 2000), (3) the spatial and organizational scale at 

which conservation should focus (Folke et al. 1996, Franklin 1993b, 

Orians 1993), and (4) property rights (Geisler and Daneker 2000, 

Lee 1993). Polarization extends from sustainable development and 

resource extraction on the one hand to preservation of genetic diversity through establishment of ecological reserves on the other. Our 

current debate is counterproductive because it is based on untestable assumptions embedded in deeply held worldviews and ethical 

beliefs (Costanza et al. 2000, Worster 1994). Nevertheless, the public is beginning to formulate cultural definitions of the term (Ray 

1996) and demand sustainability through the market place, political 

processes, administrative appeal processes, and the courts. Examples 

include purchase of green-certified wood products, payment of carbon credits, donations to nonprofit organizations for the purchase of 

conservation easements, state and federal legislation, litigation, and 

international agreements and treaties (Costanza et al. 2000, Daily 

and Ellison 2002, Harwell et al. 1999, Kennett 1998).

Ecosystem Management

Ecosystem management is variously asserted as being an evolutionary step in natural resource management, a cooperative solution to 

resource management problems, a public deliberation on values, 

and a dispersion of power and authority in the natural resource 
36 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Table 4—A comparison of multiple-use-sustained-yield management and ecosystem management

Multiple-use-sustained-yield Ecosystem management Both

	Featured species

 Resource productivity

 Multiresource management

 Multiple use, site by site

 Site-specific management

 Stand-level focus

 Efficient production

 Line-staff organization

 Planning by function

 Respond to research findings

	Biological diversity

	Ecosystem health

 Integrated management

 Systems, integrated, holistic

 Landscape management

 Multiple-scale focus

 Range of natural variability

 Public-private partnerships

 Multidisciplinary planning

 Adaptive management

	Sustainability

	Meet the needs of the people in 

the long term with a sustained 

yield of goods and services

Source: Adapted from MacCleery and Le Master 1999.

management arena (Lackey 1998, 2001; MacCleery and Le Master 1999). Ecosystem management grew out of the multiple-usesustained-yield management of the 1960s during a period of increasing demands on federal lands followed by conflict, legislation, 

and litigation (table 4). Nonsustainable timber management led to 

markedly reduced area of forest land and amounts of timber available for harvest. Rather than encompassing theoretical developments in ecology and philosophical developments in conservation, 

ecosystem management remains a pragmatic tool—a means to an 

end in meeting human needs while maintaining the health and productivity of ecosystems. Ecosystem management expands the range 

of values considered by multiple use-sustained yield management 

and requires consideration of social, economic, and environmental 

interactions at a variety of spatial scales (MacCleery and Le Master 

1999). Different groups use it with different meanings; such ambiguity promotes debate and limits acceptance. Debates over the utility 

and purpose of ecosystem management bring to light fundamental 

(and historical) differences in values and beliefs and highlight where 

the scientific basis of ecosystem management may be lacking. Thus, 

ecosystem management provides an opportunity for values clarification, expressing beliefs, identifying scientific uncertainties, and 

convening diverse interests into collaborative management groups, 

and, finally, creating opportunities for novel and creative solutions to 

persistent problems at local scales.

Ecosystem management is not a technical exercise of structuring decisionmaking around self-defining ecosystems to promote 

absolute preservation; rather, it is a set of normative principles and 

operational guides for managing human activities so that they coexist with ecological processes deemed worthy of protection over 
C H A P T E R 2 Culture and Conservation 37

Figure 6—A highly diverse, cultivated landscape unit: Regine Carey’s 

Olympia, Washington, 0.4-hectare 

garden and surrounding 1.5-hectare 

managed woods contains over 140 species of cultivated and wild plants and 

35 species of indigenous birds and has 

been highlighted in regional tours of 

natural gardens. Photo by A. Carey.

the long term (Kennett 1998). Some proponents claim ecosystem 

management is founded on five global precepts: (1) equity between 

human and nonhuman communities; (2) moral consideration for 

both humans and other species; (3) respect for cultural diversity and 

biological diversity; (4) inclusion of women and minorities; (5) inclusion of nonhuman nature in a code of ethics; and (6) ecologically sound management consistent with continued health of both 

humans and the environment (Lackey 1998, 2001). Each of these 

precepts can be contested—e.g., (1) not equity among species, but 

interdependence; (2) moral consideration for human intra- and intergenerational equity requires wise use, but does not require a precept of equity among species; (3) all management (not just ecosystem management) in contemporary democratic societies is bedded 

in systems that incorporate pluralism and diverse cultures; (4) better 

to focus on intra- and intergenerational equity and sustainability in a 

code of ethics; and (5) better to recognize limits to system capacity. 

In addition, ecosystem management is based on four major assertions that also are contested (Lackey 1998). First is the assertion 

that ecosystems are real and, thus, ecosystems can and should be 

managed. Some assert that ecosystems lack clear spatial definition 

and are imbedded systems, with management practical only at certain scales, with different approaches at each scale. Thus, given that 

humans are limited cognitively, management cannot be fully successful. Nevertheless, ecosystems are as real and tangible as anything 

in life, and cognitive limitations and uncertainty can be addressed 

with intentional systems management (Carey et al. 1999c). 

The second assertion is that natural, undisturbed ecosystems are 

inherently preferential to disturbed ecosystems. Additionally, native 

species are more important than exotic species and, therefore, biological diversity should not be reduced. In 

reality, few ecosystems have not been historically altered or influenced by people, 

exotic species include some of our most 

aesthetically and commercially valued ornamental and food plants (fig. 6), and native diversity often can be enhanced by intentional management (e.g., Carey 2003a, 

2003c; Carey and Curtis 1996; Thysell and 

Carey 2001a). 

The third assertion is that everything 

is connected to everything else (callout 1). 

Thus, ecosystem management would be 

(continued on page 44)
38 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Callout 1—A. Carey’s Science Findings July 2003, page 1
C H A P T E R 2 Culture and Conservation 39

Callout 1—A. Carey’s Science Findings July 2003, page 2
40 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Callout 1—A. Carey’s Science Findings July 2003, page 3
C H A P T E R 2 Culture and Conservation 41

Callout 1—A. Carey’s Science Findings July 2003, page 4
42 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Callout 1—A. Carey’s Science Findings July 2003, page 5
C H A P T E R 2 Culture and Conservation 43

Callout 1—A. Carey’s Science Findings July 2003, page 6
44 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

done best across large geographical areas. In reality, landscape character is conditioned by climatic, geomorphic, and biogeographic factors rarely modified by ecosystem management and determined by 

the array of biotic communities that compose the biotic landscape. 

The spatiotemporal arrangement of these communities determines 

the quality of the landscape for any particular purpose or sets of purposes through time (Carey et al. 1999c), and management at both 

stand and landscape levels is appropriate (Carey 2003a, 2003c). 

The fourth and final assertion is that there is a moral imperative 

for ecosystem management—the benefits and costs of management 

are accruable to all ecosystem components, not solely to people. This 

crucial assertion requires global action. An equally crucial assertion 

is that people have a moral requirement for intra- and intergenerational equity (Goodland 1995) that requires even stronger action. 

Ecological worldviews are in contest with profound implications for ecosystem management (MacCleery and Le Master 1999, 

Partridge 2000, Reid 1996). For most of history, people had direct 

and personal connections to the land as their source of sustenance. 

In developed nations, personal connections between resource consumption and production have been severed for most people. Linkages between “food and fields, forests and hearth, and home” are 

nonexistent. A common view assumes that natural ecosystems have 

a natural balance or equilibrium not found in managed ecosystems, 

that pristine nature is sacred, and that landscapes should be separated into those substantively modified by people and those not. Paleobiology belies this view (Reid 1996). An emerging view challenges 

assumptions of natural equilibrium and classification of landscapes 

as natural or humanized. This view argues that the natural world is 

dynamic, and holistic management is needed to sustain natural and 

cultural systems. Huge areas of federal land are allocated to reserves 

under the worldview of natural balance. This belief in an “order of 

nature” characterized by integrity, stability, equilibrium, and selfregulating mechanisms has led to a library of national and international policies, laws, and regulations (Partridge 2000). 

Ecologists and philosophers have challenged each of these beliefs, which pose important questions. Are romantic images of nature and reserves a sufficient basis to assume reserves and wilderness can be maintained as envisioned? Will human intervention be 

needed to maintain the health and biodiversity of reserves? If there 

is no natural equilibrium, stability, or self-regulation, are extinction, 

loss of biodiversity, limits to growth, and sustainability important? 

Can a fundamentally noninterventionist policy achieve the goal of 

(continued from page 37)
C H A P T E R 2 Culture and Conservation 45

maintenance of biodiversity? What emerging knowledge will give 

insight into holistic integration of humans and nature? What are 

the ramifications of not exploring new ways of thinking about active 

resource management? These questions call for a better articulated 

form of ecosystem management. It is past time to rethink ecosystem 

management (Reid 1996). 

There is another unfinished agenda for ecosystem management 

(MacCleery and Le Master 1999). This agenda includes problems 

of fragmentation of wild and cultivated lands by residential subdivision and urban development; degradation and loss of forest and 

grassland communities once maintained by frequent, low-intensity 

fires; loss and fragmentation of late-seral forest by timber harvesting and narrow-focus forestry; degradation and loss of riparian and 

wetland communities; damaging effects of air pollution on forests 

and wetlands; displacement of native species by exotics; loss of rare 

and unique types of ecosystems; and deforestation in developing nations. This is the agenda of total landscape management and global 

cooperation. United States federal agencies manage over 120 million 

hectares of public land (approximately a half million square miles or 

twice the combined area of Washington, Oregon, and Idaho). Many 

of these agencies are in varying stages of crisis because of unclear or 

contradictory agency missions, internal malfunctions, and lack of 

responsiveness to foreseeable problems (Samson and Knopf 2001).

Ecosystem management requires some measures of effectiveness. Ecosystem health is the most commonly referenced measure of 

ecosystem management effectiveness (Lackey 2001). There is, however, no universal conception of ecosystem health. Some find the 

concept too value laden, too abstract, and too contentious. Many 

perceive health concepts to be relegated to individuals and not appropriate to populations, communities, and systems. Such a perception shows a lack of knowledge in the fields and institutions of epidemiology, disease prevention through environmental management, 

public health, and occupational safety and health and in the fact 

that the roots of landscape ecology lie in landscape epidemiology 

(Carey and McLean 1983; Carey et al. 1978, 1980a, 1980b). Many 

conclude that because there is no consensus, the concept is not useful—conclusions all too similar to those drawn for almost all conservation concepts. Nevertheless, ecosystem health can be defined as 

the preferred state of ecosystems modified by human activity (Karr 

and Chu 1999). The concept of ecosystem integrity (the unimpaired 

condition of ecosystems not influenced by people) can be used to set 

benchmarks by which management effectiveness can be measured. 

The biotic integrity of key communities and keystone complexes are 
46 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

especially useful when benchmarks are defined by natural ecosystems that exhibit longevity, resistance to disturbance, resilience in 

recovering from disturbance, and capacity to provide valued goods 

and services, including conservation of biodiversity (Carey et al. 

1999c) (table 5). The utility of ecosystem health includes comparing alternative desired future states, comparing alternative pathways 

to that state, and measuring progress from a past state toward the 

future state.

With no consensus on process management or total quality 

management that incorporates natural benchmarks (Rummler and 

Brache 1995, Schein 1994), effective measures of change, and carefully defined management goals, conservation biologists suggest using a natural variability concept (Landres et al. 1999, Lindenmayer 

et al. 2000, McIntyre and Hobbs 1999). This approach asserts that 

the range in natural variation in past conditions and processes provides adequate context and guidance for managing ecological systems today and in the future, and disturbance-driven spatial and 

temporal variability is a vital attribute of ecological systems. The use 

of natural variability began out of a search for a legally defensible 

strategy for maintaining biodiversity and threatened, endangered, 

and sensitive species. It is also used where maintaining biotic integrity is the primary goal. However, the proposition that natural 

variation provides for the maintenance of biotic communities is 

oxymoronic. Natural variation emphasizes random processes that 

result in random or haphazard assemblages of the regional species 

pool, unlike biotic communities that are assemblages based on interactions among species conditioned by the environment. Either 

an assemblage is a random collection, or it is a biotic community 

developing from interactions among species in the context of the 

immediate or nearby environment. The nonequilibrium-stochasticity paradigm imposes no particular value on any species or any set of 

species, nor any mechanistic basis for biotic integrity (Landres et al. 

1999). Thus, further examination of the natural variability concept is 

in order. The concept has seven premises:

 Human activities diminish the viability of many species.

 History implies that a “coarse filter,” or an array of vegetative 

conditions mimicking historical conditions, could maintain 

biological diversity. 

 A coarse-filter strategy requires few external subsidies and is 

more cost effective than other strategies. 

 Natural variability is a useful reference for evaluation of the environmental impacts of people.
C H A P T E R 2 Culture and Conservation 47

Table 5—A comparison of unique species and ecosystem health under two management approaches, timber focus and biodiversity focus

Management focus

Ecological measure Timbera Biodiversitya

Unique speciesb 0 14

Ecosystem healthc 32 98

Vertebrate diversity 64 100

Forest-floor function 12 100

Ecological productivity 19 94

a Both pathways include an even flow of timber from a landscape maintained as a shifting, steady-state mosaic.

b Unique species is the total number of species of wildlife unique to the 

particular management focus.

c

 Ecosystem health is a percentage of the maximum possible in a fully 

regulated forested landscape. Ecosystem health was calculated as the average of the modal percentages of maximum potential vertebrate diversity, 

forest-floor function, and ecological productivity (measures functional 

groups) summed from stand values.

Source: Adapted from Carey et al. 1999c.

 Natural variability provides context that is important to understanding driving factors.

 Environmental factors and disturbances are strong, lasting, and 

key structuring factors.

 Spatial heterogeneity itself is an important component of ecological systems.

Problems associated with these premises are many and profound. 

First, the premise that a retrospective view will focus on the set of 

factors ultimately responsible for biodiversity is questionable. Cursory retrospective investigations have produced mixed results at best. 

Nor does this approach identify key variables that can be monitored 

to determine if biodiversity goals are being met. At best, monitoring implementation of the strategy is possible (e.g., hectares cut per 

year, number of watershed analyses completed, or number of reserves 

set aside on paper). Research can help identify key factors and their 

function, but then this new knowledge abrogates the need for relying 

on a coarse filter. Second, the premise that there exist areas with ecological conditions relatively unaffected by people and that the range 

of natural variation in these areas is appropriate to other areas with 

more substantial human influence is tenuous at best. Some of the 

most pristine forests in the world, however, are Pacific Northwest 
48 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

old-growth forests, which might well produce useful benchmarks 

for management to conserve biodiversity. Extrapolating beyond the 

sampling universe is always risky. Pristine environments, when they 

exist at all, generally are harsher (steeper, higher, drier, wetter, colder) 

than managed environments. Third, the premise that the biodiversity of a large area is a product of the full range of natural variation 

there as opposed to a more limited set of conditions is unsupported. 

Stochastic disturbances by definition are unlikely to uniformly maximize or maintain diversity; some conditions produced will be very 

conducive to native diversity, some may be quite inimical. Fourth, 

the range of natural variability, when imposed on a managed landscape may fail to produce desirable future conditions or produce the 

goods and services desired from that landscape. More intentional 

ecosystem management may have a better chance of accomplishing human goals, including maintenance of biodiversity. Fifth, the 

natural variability concept assumes a consensus can be reached on 

managing for stochastic disturbance, when such a consensus is likely 

to become increasingly improbable with increasing human demands 

on a landscape. Sixth, given increasing human populations, increasing demands on natural resources, and decreasing areas of wild and 

quasi-wildlands broken into much smaller areas than existed prior to 

European settlement of North America, it may be neither possible 

nor prudent to try to re-create the disturbance regimes of more than 

300 years ago (Carey et al. 1999c, Reid 1996). McCool and Kruger 

(2003) described this approach as “management that proceeds with 

little scientific understanding of consequences and uses assumptions 

about the ‘intrinsic goodness’ of the management activity.”

More complex, diverse, and integrated organic management 

models than range in natural variation are necessary to understand 

and adapt ecosystem management to a globalized environmental 

and sociopolitical world (Kennedy and Dombeck 1999). The 20thcentury agency-machine bureaucracy approach that could implement range-of-natural-variation ecosystem management is no 

longer appropriate. General sustainability, complex systems management, social values, stewardship, and collaborative management 

hold sway (table 6). There is considerable public skepticism about 

government, science, and technology. Still, public acceptance is essential to every resource management decision of public agencies 

(Shindler et al. 2002). The conflicting roles that management agencies have been directed to play in the past—resource protection and 

provision of commodities—have made them vulnerable to social 

criticism. Past commodity production without understanding what 

was necessary to maintain biodiversity produced violations of the 
C H A P T E R 2 Culture and Conservation 49

Table 6—The th-century machine model vs. the 1st-century organic model of natural resource management

20th-century machine model 21st-century organic model

	Sustained yield/economic efficiency

 Resource inventory

 Intensively managed plantations

 Omnipotent foresters

 Focus on a stand

 Anti-entropy imperative

 Science illuminates the path

 Top-down goal setting

 Implementation of complex law

 Local-regional focus

	Sustainable healthy ecosystems

	Systems monitoring

 Multifaceted, multivalued forests

 Interdisciplinary teams, public participation

 Focus on hierarchy of scales, stand-region

 Open, accepting, adaptive organization

 Science as one of a set of values

 Bottom-up field and community planning

 Simplify, humanize, facilitating regulation

 Local community within national and global context

Source: Adapted from Kennedy and Dombeck 1999.

public trust. These violations have ranged from breach of the social 

and psychological contracts with individuals and communities that 

depended on renewable resources for economic activity and management that violated the spirit and intent of federal legislation such 

as the Multiple Use-Sustained Yield Act and Endangered Species 

Act to failures of regulatory agencies to enforce laws and regulations 

(judged “capricious” by federal courts). Range-of-natural-variation 

ecosystem management potentially has significant, perhaps irreversible, consequences to the environment and to human communities 

that depend on the environment for sustenance, security, shelter, 

spirituality, and leisure. It increases the anxiety of long-term rural 

residents who feel increasingly alienated by an apparently remote 

and insensitive federal government, overwhelmed by growing global 

economic complexity, antagonized by an enlarging environmental 

elite, and alarmed by vacillating land management policy (McCool 

and Kruger 2003). At best, public judgments are always provisional, 

never absolute or final because social acceptance is a process, not 

and end product. Acceptable practices and policies must be biologically and physically feasible, economically efficient, equitable, culturally acceptable, and operationally practical (Shindler et al. 2002). 

If management for the range of natural variation is attempted, lost 

trust may never return.

Total Landscape Management

The myth of untouched nature works against protection of the real 

world that is shaped jointly by human activities and nature. Twothirds of terrestrial Earth is covered by agriculture, grazing, and 
A

B

C

D

50 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 7—Seral-stage arrangement 

and composition of the Clallam River 

Planning Area after regulation and 

300 years of simulated management 

for (A) timber production with minimal riparian protection; (B) timber 

production with wide buffers emphasizing small streams; (C) biodiversity 

with a 30 percent late-seral forest goal, 

by using a mix of timber management 

and biodiversity management and 

variable riparian management zones; 

(D) maximum biodiversity by using 

a mix of 70- and 130-year rotations 

with biodiversity management and 

variable riparian management zones. 

Seral-stage categories are ecosystem 

initiation (EIS), competitive exclusion 

(CES), understory reinitiation and development (URS/DUS), and late-seral 

forest (LSF: niche diversification and 

managerially fully functional forest) 

(Carey et al. 1999c).

managed forests (Farina 2000). Economic globalization is producing 

new disturbance regimes and new driving forces. The market economy is one of the oldest human adaptations to the unpredictability of 

local environments and to high spatial variability in the distribution 

of resources (di Castri 2000). Recognition of market economies is 

essential to the integration of economics and ecology. Human activity is now the predominant evolutionary force (­Palumbi 2001). 

Both natural and human disturbance affects the fragility and 

resilience of cultural landscapes. The susceptibility of an ecosystem 

to undergo changes in composition and structure because of perturbation (fragility) and its ability to recover to its prior state after 

disturbance (resilience) is as important in managed landscapes as 

in natural landscapes. Biological diversity may be higher in cultural 

landscapes than in remnants of natural landscapes, depending on 

landscape heterogeneity and purpose of cultivation (see fig. 6). If 

land is properly managed and zoned, humanity can use biological 

resources without diminishing the biota’s capacity to meet future 

generation’s needs (Reid and Miller 1989). Intentional management 

can produce highly diversified ecological systems that are sustainable (Carey et al. 1999c) (fig. 7). The resilience of cultural landscapes 

is often enhanced by reduction in vulnerability to natural environmental stresses such as flooding and fire by regulating waterflow and 

by removal of dry biomass. The challenge is to maintain cultivated 
C H A P T E R 2 Culture and Conservation 51

landscapes with human co-adaptation within the global economic 

landscape (Farina 2000). Unconstrained growth and development 

bodes poorly for sustainability (see fig. 2D). Throughout Europe and 

North America, major aquatic, forest, grassland, and cultural ecosystems have been degraded (Farrell et al. 2000, Regier and Baskerville 

1986). Redevelopment (restoration) of degraded landscapes requires 

global thinking and local action. The transition from development 

to redevelopment (exploitation to husbandry) necessarily involves 

substantial tension among governments, industries, and publics that 

is heightened by a mutual lack of trust. Redevelopment requires 

geographic control in implementation of management—plans must 

specify where local events will take place in order to achieve the 

desired regional effect.

Culture and Contemporary Players in 

Conservation

Human societies and the Earth form a complex system that is 

subject to abrupt shifts from one pattern of behavior to another. 

The Earth and its people may well be at the crux of social transformation. Which world lies ahead? The 2050 project (Hammond 

1998) visualized three scenarios: Market World, Fortress World, 

and Transformed World. In Market World, economic reform and 

technological innovation produces rapid economic growth, and the 

global economy delivers modern technologies and products to all 

countries resulting in prosperity, peace, and stability. In the Fortress 

World, market growth fails to redress social wrongs and prevent 

environmental disasters; large portions of humanity are left out of 

prosperity; the economy stagnates and fragments producing enclaves of wealth and prosperity within misery, desperation, violence, 

and conflict. In the Transformed World, fundamental social and political change produces market forces that lead to power sharing and 

social coalitions that produce local community-based decisionmaking. Which scenario will come about? Each has profound implications for conservation of biodiversity and the knowledge needed to 

inform it.

Cultural Streams in the United States

American culture is distinct from other cultures of the world but is 

still internally heterogeneous (Ray 1996). American culture can be 
52 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

characterized by two primary variables: socioeconomic status and 

cultural change. This cultural variable can be divided into three subcultures—the traditionalists, modernists, and cultural creatives—

each contemporary, but each reflecting an era-specific dominant 

worldview (past, present, and potential future). Traditionalists include conservative, religious, low-income and low-educated elderly 

people as well as upper middle class cultural and economic conservatives; together these two groups constitute 30 percent of the 

adult population of the United States. Their numbers are generally 

in decline (an aging population), but are being bolstered by intense 

recruitment by the religious right. The traditionalists are particularly interested in family values, have a low regard for civil liberties, 

and differ internally among socioeconomic classes in support for 

big business. The modernists are the current cultural mainstream. 

The media emphasizes their malaise about what the modern world 

has come to be. They make up 47 percent of the population. They 

have a wide range of incomes but average almost twice the income 

of the traditionalists. They include factory and office workers, engineers, doctors, and business people. One in eight in this group are 

free-market conservatives with a materialist focus on status and success with a heavy work ethic. They are likely to be opposed to ecological sustainability. The cultural creatives (24 percent of the total 

population) are primarily upper-middle income and middle aged; a 

majority (60 percent) are women. They can be subdivided into two 

groups, the greens and the core cultural creatives. The core holds 

both person-centered and green values. They are concerned with 

spirituality, self-actualization, self-expression, and new ideas. Core 

cultural creatives are leading-edge thinkers; women outnumber men 

2:1. Greens (13 percent of the total population) have values centered 

on the environment and social concerns. Certain values cut across all 

the major subcultures. More than 50 percent of each group believes 

in financial materialism, rebuilding communities, eliminating violence against women and children, xenophilism (attraction to foreign peoples and cultures), and voluntary simplicity. Moreover, these 

more universal values include nature as sacred, general green values, 

and ecological sustainability (table 7). More than 80 percent of cultural creatives are concerned with rebuilding communities, treating 

nature as sacred, general green values, and ecological sustainability 

(Ray and Anderson 2000). To summarize these findings in different 

words, American culture overall is characterized by beliefs in social, 

economic, and environmental sustainability.
C H A P T E R 2 Culture and Conservation 53

Table 7—Values of American subcultures expressed as percentages of each of the three main cultural streams 

ascribing to major values (percentages greater than or equal to 65 percent are in bold type)

Values Traditionalists Modernists Cultural creatives

Religious 

Traditional relationships

Financial materialism

Cynicism about politics

Secular

Success is high priority

Hedonism

Rebuild communities

Fear violence 

Xenophilism

Nature as sacred

Green values

Ecological sustainability

Voluntary simplicity

Relationships important

Feminism in work

Altruism

Idealism

70

55

61

29

15

11

5

86

84

69

65

58

52

65

65

45

55

36

36

25

82

48

42

36

12

84

75

63

72

59

56

53

49

56

32

32

31

26

51

19

29

12

4

92

87

85

85

83

83

79

76

69

58

55

Source: Adapted from Ray and Anderson 2000.

Leadership by Nongovernmental Organizations

Conservation organizations have long been active lobbyists and litigants for their causes, but now have moved more directly into the 

research, technology transfer, and management arena. The Nature 

Conservancy, Forest Stewardship Council, Northwest Ecosystem 

Alliance, Pacific Forest Trust, and many others have wrested land 

management and conservation leadership from both state and federal agencies. The Nature Conservancy received $37 million in federal 

funding in 2000. Coalitions, such as The Nature Conservancy and 

the Malpai Borderlands Group as well as The Nature Conservancy 

and Red Canyon Ranch, have achieved credibility outside, above, 

and beyond the traditional ranching-range science-federal and state 

agencies community ( Jensen 2001). It seems these and other (Daily 

and Ellison 2002, Johnson et al. 1999) coalitions can effectively resolve conservation issues that are not simply conservation questions 

but ultimately questions of cultural values—such as whether or not 

ranching should continue. Coalitions of nongovernmental organizations are driving conservation policies and conservation activities internationally. In Central America, a coalition of The Nature 

Conservancy, The World Resources Institute, the World Bank, and 
54 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

others along with the United Nations, Netherlands, and Germany 

have begun a 40-year project to establish a system of reserves and 

corridors that transcends eight countries—“one of the largest, most 

ambitious conservation initiatives in the world” (Kaiser 2001). The 

Central America project is a leap beyond the past sustainable development-conservation initiatives in the Third World (Food and Agriculture Organization of the United Nations 1990). Forest Stewardship Council certification confers a credibility and stature that 

also transcends any associated with state or federal management or 

research; thus, in the last 2 years, the Washington Department of 

Natural Resources, the Fort Lewis U.S. Army installation, and a 

number of private land and forest products marketing groups in the 

Pacific Northwest have sought certification. The Pacific Forest Trust 

has pursued paying landowners for conservation easements and the 

practicality of trading in carbon credits (see also Daily and Ellison 

2002). The Northwest Ecosystem Alliance, with contributions from 

the general public and “Microsoft millionaires,” purchased key, ecologically significant timber rights on the Loomis State Forest from 

the Washington Department of Natural Resources. The alliance, 

with a coalition of environmental groups, is now attempting to build 

local coalitions of all stakeholders to promote watershed restoration 

and ecological forestry through collaborative management.

Charity is a new force in environmental issues ( Jehl 2001). The 

Pew Charitable Trust, a $4.8 billion foundation, is the largest grantmaker to environmental causes focusing on forest protection, global 

warming, and marine conservation. The trust spent $52 million in 

2001, compared to a USDA Forest Service investment in research of 

$242 million (U.S. Department of Agriculture 2003). Other foundations—David and Lucille Packard Foundation, Ford Foundation, 

Robert W. Woodruff Foundation, and W. Alton Jones Foundation—allocate more than $700 million per year to grants related to 

the environment and animals. 

Professional and scientific societies (American Fisheries Society, Ecological Society of America, Society of American Foresters, 

Society for Conservation Biology, The Wildlife Society, and others) 

now routinely issue white papers, policy statements, editorials, and 

testimony to legislative bodies and urge their members to lobby actively on conservation issues. “Deep ecologists” claimed the moral 

high ground by asserting the spiritual value of wilderness and wilderness for its own sake (Reid 1996). However, a more transcendent 

cultural trend now incorporates the spiritual value of the oneness of 

self, family, community, and nature (Maser 1994, Ray 1996, Wilber 

1995).
C H A P T E R 2 Culture and Conservation 55

Towering Douglas-fir giants in Olympic National Forest, near Quinault, 

Washington. Photo by T. Wilson.

Managing Public Lands

The federal government has lost its historical grip on the West that 

began with the imperialism of Manifest Destiny under Thomas Jefferson and Teddy Roosevelt and that was perhaps irreparably diminished by declining budgets under Ronald Reagan (Behan 2001, 

Kemmis 2001). The USDA Forest Service received fewer and fewer 

resources with which to assert its jurisdiction or fulfill its obligations. The adherents of exploitive philosophies, in some cases the 

actual descendants and in other cases the ideological descendants 

of the homesteaders, cattle barons, lumber pirates, and mining interests that initially settled the West following the Homestead Act 

of 1862, the Timber Culture Act of 1873, and the Desert Land Act 

of 1877, are pitted against the descendants of the environmentalist heirs of the preservation philosophy underlying the creation of 

Yellowstone National Park in 1872, the “midnight reserves” of 1907, 

the National Environmental Policy Act of 1969, and the Wilderness 

Act of 1964. Even with the National Forest Management Act of 

1976, which sought to maintain a natural resource and conservation 

posture, federal land managers have found themselves increasingly 

paralyzed by appeals and litigation. 
56 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

There seems to be a growing consensus across political lines that 

centralized authority for natural resource decisionmaking must be 

replaced with decentralized collaborative stewardship (Behan 2001, 

Kemmis 2001, Kennett 1998, Lewis 2001, Prugh et al. 2000, Rey 

2000). Our common goals for conservation of natural resources include a society that works for our descendants and us ecologically, 

economically, morally, culturally, and politically (Prugh et al. 2000). 

What sustainability is really about is the scope, quantity, richness, 

and benignity of human culture, the biosphere and the economic life 

we make from it, and the distribution of those economic and social 

benefits now and over time. Communities are the primary locus of 

responsibility for creating a sustainable world, and a sustainable society must be built on a foundation of local communities. Thus, we 

need a politics of engagement, not consignment. Strong democracy 

makes communities stronger and more reflective. Communities, 

then, must create the vision, broad stakeholder base, wide citizen 

engagement, tolerance for pluralism, and adaptability to changing 

circumstances that governmental agencies have not been able to 

create alone. Amenity migrants (rock climbers, hunters, fly fishers, 

skiers, and others) to the New West define themselves avocationally, 

in contrast to the wave of immigrants that became the cowboys, 

loggers, and miners of the Old West. Both are tied to the land. The 

Secure Rural Schools and Community Self Determination Act recoupled local citizens with federal lands by establishing local advisory groups for each national forest and Bureau of Land Management unit, with financial support for stewardship investments on 

federal lands where local consensus can be achieved (Rey 2000). 

Rey (2000) posited some guiding principles for this stewardship: (1) 

continuous process improvement in reducing impacts of commodity production on the land; (2) a change from the doctrine of “the 

infallibility of nature left to its own devices” to a philosophy of “man 

as part of a dynamic environment with changing ecosystems;” (3) 

policies that favor people and ecosystems, not one or the other; (4) 

change from a doctrine of primacy of national interest groups with 

decisionmakers selected from national organizations to a doctrine 

of local community control. 

Managing Private Lands

Both governmental and nongovernmental organizations are more 

and more influencing management on private lands through regulation, incentives, conservation easements, and outright purchases 
C H A P T E R 2 Culture and Conservation 57

to place the lands in trusts or public ownership. Even industrial 

forest-land managers are finding themselves being held accountable to public values (Loehle et al. 2002). Nearly 175 million hectares of privately owned forest land (58 percent of all forest land) in 

the United States is increasingly threatened by population growth, 

urbanization, and development (Best and Wayburn 2001). For example, in the Pacific Northwest, the Pacific Forest Trust has implemented conservation easements worth $80 million on about 12,000 

hectares of land and provides conservation advisory services on an 

additional 500,000 hectares (Pacific Forest Trust 2001).

Property Ownership and Conservation

Land ownership in the United States is a mosaic of legal interests 

that are conditional rather than absolute (Geisler and Daneker 

2000). Our public lands are a great reservoir of pride, mystique, and 

national identity. Federal, state, and local governments own about 

42 percent of all U.S. land. Most federal lands, however, are split 

estates where permittees have acquired ownership rights. In the 

United States, there exists an “almost defiant conceit” that private 

ownerships are the highest and best use of land and the center of 

American civil liberties, lifestyle, and individualism.” But the federal 

government has secured rights to 1.2 million hectares of private land 

through leases, agreements, and easements. Achieving conservation 

through government regulations, thus raises issues of (1) the constitutionality of property regulation without restriction in terms of 

“uncompensated takings,” (2) privatization, and (3) ethics of ownerships, social justice, land tenure, stewardship, equity, and fairness. 

In other words, the overriding issue is the fundamental balance between rights of individuals and those of society. Most private lands, 

however, have a perpetual social mortgage. For example, the U.S. 

Department of Agriculture subsidizes conservation on private lands 

with about $1 billion per year. Even more alternatives to private and 

public property have emerged, are evolving, and are rapidly growing. In third-sector property, ownership is neither public nor private; 

property serves to meet broadly defined social needs as well as individual needs, not merely to increase wealth. The locus of control 

is local and management is decentralized. Third-sector property is 

social property, with value generated by public action, not by an individual property owner. Third-sector properties include a variety 

of community land trusts, limited equity cooperatives, conservation 

easements, and many other innovative schemes.
58 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

One alternative theory of public ownership, the General Land 

Ordinance of 1785, created 60 million hectares of state school trust 

lands in 22 states compared to 30 million hectares eventually allocated to national parks, 40 million hectares to wildlife refuges, 75

million hectares to national forests, and 115 million hectares to the 

Bureau of Land Management (Souder and Fairfax 2000). About 5

million hectares are in tribal trusts; 175 million hectares of forest 

land are privately owned (Best and Wayburn 2001). An unknown 

amount of land is held in trusts or easements by pension funds, 

conservation organizations, and other groups. Such trusts separate 

title, benefit, and management control. The obligations that bind 

the trustor, settler, trustee, and beneficiary are called fiduciary relationships. The principles of trusts are clarity, accountability, enforceability, perpetuity, and prudence. Trustees must meet exacting 

requirements of fairness, openness, honesty, and full disclosure. Intergenerational equity is mandatory requiring that the productive 

capacity of the trust be maintained in perpetuity—the framework 

for sustainability. In contrast, federal lands are not trust lands, there 

is limited accountability, oversight is congressional, and both agencies and legislators seek benefits for their constituents and conceal 

the extent to which different user groups are subsidized. Public 

mistrust and dissatisfaction with federal land managers may lead to 

placing more federal lands into trusts (Behan 2001, Kemmis 2001, 

Rey 2000). Other trusts include public trust (the sovereign’s duty to 

protect public values in tidelands and waterways), land trusts with 

the focus to protect land from development, and charitable trusts. It 

seems the concept of land ownership in the United States is almost 

as dynamic as other parts of U.S. society. As pressures from growing 

populations increase demands and expectations from forests, one 

emerging mechanism for conservation seems to be creation of trust 

lands (and community forests) as replacements for public and industrial lands.
C H A P T E R 3

Individuals, Society, and 

Conservation

Human impacts on the global biosphere now control many facets 

of ecosystem function (Palumbi 2001). In addition to altering global 

ecology, technological and human population growth also affects 

evolutionary trajectories, dramatically accelerating evolutionary 

change in other species, especially in commercially important pest 

and disease organisms. There are, perhaps, 1.4 million living species known to science and as many as 14 million in total (Wilson 

1999a). Most (98 percent) birds are known; 1.5 percent of algae have 

been described; and bacteria constitute a black hole, with less than 

1 percent of species described. On the other hand, more than 98

percent of the species that have ever lived have vanished, and many 

ecologists believe we are facing an unprecedented wave of extinctions owing to habitat destruction, spread of exotic species, pollution, overharvesting, and disease. The importance of biodiversity is 

twofold (Wilson 1999a): (1) the more species living in an ecosystem, 

the higher its productivity and the greater its ability to withstand 

drought and other kinds of environmental stress, and (2) biodiversity contributes to clean water, enriched soils, clean air, pharmaceuticals, crops, and fibers. However, care must be taken not to confuse the issues around biodiversity and to create subterfuges for the 

economic importance of noncommodities, even if these resources 
60 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

have noneconomic aesthetic values, such as a beautiful landscape 

(Ehrenfeld 1976). Maintaining biodiversity can be seen as a moral 

obligation to avoid destroying creation (Wilson 1999a). All environmental problems are innately ethical, seeking a right relationship 

between people and other living things and between generations. 

Every society has three forms of wealth—material, cultural, and 

biological—and the responsibility not to diminish this wealth for 

future generations.

Human health and well-being fundamentally depend on a clean 

and steady supply of water and fertile soil to produce renewable resources for food, fiber, and other products (Szaro et al. 1999). We 

have gone from a world relatively empty of humans to one full of 

humans. Ecosystem services necessary to the function of Earth’s 

life-support systems are also necessary for economic production and 

human welfare (Costanza et al. 2000). There is a consensus among 

a broad spectrum of scholars that the scope and magnitude of environmental problems threatens the sustainability of Earth’s life support systems (Dasgupta et al. 2000). At the Earth Summit in Brazil 

1992, there was universal agreement that conservation of biodiversity is a serious global concern. However, there was intense disagreement on how to balance conservation with social, economic, and 

sustainable-use factors (Szaro 1996). This disagreement is in part 

due to the principles of sustainable governance (responsibility, scalematching, precaution, adaptive management, full cost allocation, 

and participation) (Costanza et al. 2000), which are at odds with 

the law of the commons, the psychology of large groups that leads 

to diffusion of responsibility, gross socioeconomic inequities within 

and among nations, histories of racial discrimination and economic 

exploitation, the lack of universal democratic government, variation 

in worldviews of nature, intentional and unintentional obfuscation, 

a predominance of free-market economics, self-interest, and greed. 

Davidson (2000) believes the Malthusian-Ehrlich-Meadows-Daly 

limits to growth paradigm is not useful ecologically or economically 

and politically hinders conservation. Its use has been similar to “crying wolf ” and blaming the poor. 

A tapestry paradigm (fig. 8) is a useful alternative to the limits and optimist paradigms. It is clear that (1) humans can destroy 

the environment, (2) any specific natural resource is finite, and (3) 

biological and physical systems underlie all economic activity and 

provide constraints. However, biophysical limits have rarely limited 

economic growth because ways are found to adapt and continue to 

expand. Continued economic growth has not caused collapse, but has 

continued environmental degradation. The limits paradigm focuses 
Environmental quality

Economic growth

Socioeconomic 3

Socioeconomic 2

Socioeconomic 1

Arrangements

C H A P T E R 3 Individuals, Society, and Conservation 61

Figure 8—The tapestry paradigm, 

an alternative to limits to growth: 

Managing the socioeconomic structure of production can contribute 

to sustainability through development rather than growth (adapted 

from Davidson 2000). Under all 

three socioeconomic arrangements, 

increased growth leads to decreased 

environmental quality. However, 

socioeconomic arrangement 1 provides 

much higher environmental quality for 

a given level of growth than arrangements 2 or 3.

on resources, consumption, and human population. Examination of 

social structures of production and consumption offer greater hope 

for understanding and slowing environmental destruction. In the 

tapestry paradigm, economic growth means increased efficiency of 

material use (less waste and more recycling) and value-added manufacturing (developing systems that, e.g., harvest trees, make lumber 

and pulp, recycle waste chemicals from the pulp, use sawdust and 

trim slabs for fuel, produce furniture, and so on). Economic development provides for increased human welfare without increased use of 

resource or increased production of waste. The difference between 

growth and development is at the heart of general sustainability 

(Goodland 1995). Alleviating human misery and poverty is essential to solving global environmental problems. In the United States, 

there is not as profound a connection between poverty and conservation because social institutions are well developed and the economy is diversified and based more on development than on growth 

in use of renewable resources (imports substitute for growth and 

shift the negative effects of growth to other societies). Nevertheless, progress in conservation in the United States still depends on 

progress in developing a general—environmental, economic, and 

social—sustainability.

At the heart of ecological productivity is biodiversity. Biodiversity is an inherent property of all ecosystems. Most management 

issues are concerned with a small proportion of total biodiversity—

ensuring adequate levels of ecosystem function is more important 

than the total number of species. Moreover, species diversity can 

change in response to both natural processes and human actions. 

Changes in species diversity usually indicate that either physical or 

biotic conditions have altered; these alterations may have impacts 
62 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

on human welfare. Species diversity is influenced by the physical 

conditions of climate, nutrient availability, physical structure or heterogeneity, and environmental disturbance. Biological interactions 

include competition, predation, mutualisms, parasitism, and disease. 

Thus, biodiversity is a complex function of the interaction of physical and biotic factors. This suggests that the severity of impacts of 

management on species diversity should be evaluated in relation to 

the background of natural influences on species diversity. Invasion 

and spread of nonnative species are leading threats to genetic and 

species diversity in wildlands and also have potential to adversely affect human welfare. Sustainable resource management requires understanding factors that regulate species diversity, specifically those 

factors that either increase or decrease genetic and species diversity.

I know no safe depository of the ultimate powers of society 

but the people themselves and if we think them not enlightened enough to exercise their control with wholesome 

discretion, the remedy is not to take it from them, but to 

inform their discretion by education (Thomas Jefferson in a 

letter to William Charles Jarvis, September 28, 1820, cited 

in Maser et al. 1998).

Ways of Thinking, Learning, and Knowing

The ways people dwell in the natural world inspire the ways they 

understand, explain, and look at nature because both sociology and 

nature influence their conceptions and attitudes toward nature (Rozzi 1999). We have inherited ways of thinking based on millennia of 

slow growth or no growth (Ehrenfeld 2002) and selective pressures 

from immediate, highly certain, threats to individual survival (Ornstein and Ehrlich 1989). Kaufmann et al. (1994) summarized the 

tension from mixing short-term and long-term aspects of humanecosystem interaction: in the short run are the demands for goods, 

services, and economic livelihood; in the long run are opportunities 

for subsequent generations. The resolution must be a shift in focus 

from sustaining production of goods and services to sustaining ecological, social, and economic systems. But we need to understand 

how to get people to agree on some common visions.

Social consensus can be thwarted by people’s different ways of 

knowing. One form of knowledge rarely considered has to do with 

meanings of place; these meanings are exemplified in traditional aboriginal environmental knowledge and management systems (Sherry 
C H A P T E R 3 Individuals, Society, and Conservation 63

and Myers 2002). These systems constitute credible worldviews that 

incorporate an information base, a paradigm, norms and customs, 

objectives, social sanctions, and extensive teaching. In contrast, our 

modern state worldview incorporates selective data-based science, 

value-free problemsolving, professional administration, written laws 

and regulations, and top-down control. Sherry and Myers (2002) say 

the state worldview is a predatory model of hunter behavior combined with the tragedy of the commons that results in competition, 

individuality, property, and control, compared to the Gwitchin model of everything is alive, we are all relatives, use of the environment is 

a privilege, take only what you need and use what you take, with the 

individual and collective obligated to act responsibly for the benefit 

of future generations (see also Ford 2001, Krech 1999, Striplen and 

DeWeedt 2002, Wright 1992). Ancient conceptualizations defined 

ecosystems both in terms of discrete geographical boundaries (e.g., 

a watershed) and abiotic and biotic factors including people (Berkes 

et al. 1998). For example, Pacific Northwest family groups claimed 

watersheds as their domains, 15th-century Turks instituted watershed conservation, 15th- and 16th-century Inca developed a regional 

general sustainability, 17th-century Chinese planted trees for river 

conservation, and 17th-century Swiss used watersheds in an integrated fashion. Traditional ecological knowledge incorporated concepts of unpredictability, uncontrollability, nonlinear processes, multiple equilibria, and surprises. Traditional knowledge also depicted 

ecosystems as alive, encompassing people and, in some cases, spirits 

of animals, other natural objects, and human ancestors. The land was 

alive and full of life force (Berkes et al. 1998). Of course, peoples in 

every time and place exhibited intelligence, self-interest, flexibility, 

and ability to make mistakes (Krech 1999), but rarely as much selfinterest, greed, and disdain of equity as the European invaders of the 

“New World” (Wright 1992). 

Culture is the “hidden hand of land use planning” (Geisler and 

Daneker 2000). Race, class, and gender influence attitudes toward 

the environment within cultures (Taylor 2002). The cultural landscape defines the physical landscape. Culture is a people’s cumulative way of life, material and nonmaterial. Culture comprises morals, 

art, custom, language, religion, law, property rights, and other group 

values. It marks the corners and edges of places—which will be sacred and which will be sacrificed. The French preferred long, linear boundaries resembling alleyways, whereas the English preferred 

polygons. Thomas Jefferson invented the Township-Range-Section 

grid of modern American land boundaries (Geisler and Daneker 

2000). Culture defines the aesthetics and ethics of the lands. For 
64 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

example, in ancient Israel, land holdings were reshuffled every 50th

year. Native Americans often had communal ownership. John Locke 

asserted that land was a gift to all from God but subject to sole 

ownership if changed or improved, a concept adopted in the United 

States in disposing of its large, federal landholdings. Deep within 

American culture exists two contrasting prescriptions for individual 

happiness and public interest (Geisler and Daneker 2000): (1) private ownership as a practical extension of possessive individualism 

and (2) public ownership of land and natural resources as a superior, 

long-term form of stewardship and an ecologically sound land ethic. 

This dissonance most likely arose from the European experience. In 

1600, the population of France and England was hundreds of times 

greater than the 4 to 7 million Native Americans; Europeans had 

profoundly altered their landscapes—they had cleared over 205,000 

square kilometers of forest for agriculture, and then an additional 

65,000 square kilometers in the next century to satisfy demand for 

charcoal for smelters and naval supplies for ships (Krech 1999). 

Individual experience can be as fundamental as culture. Yukio 

Mishima (2003) declared that the physical experience of nature and 

matter (“sun and steel”) has profound effects on the mind. Knowledge gained from physical experience is diverse: practical action in 

nature leads to the discovery of knowledge, knowledge acquired by 

labor becomes second nature, and everyday thinking and action lead 

to common sense. Informal attempts to resolve conflicts about management of nature in the Pacific Northwest have spawned numerous 

anecdotes about how field trips provide physical and mental experiences of actual places and organisms that can override position-based 

thinking based on worldviews. A concept rejected as false based on 

habitual thought, worldview, or culture can be easily grasped when 

personally experienced. Perhaps, separation of the physical self from 

the nature at hand and developing attitudes, opinions, and worldviews by using primarily the mind and mutually reinforcing interpersonal communications helps account for the extreme differences 

in views about how and what to conserve in nature. The late David 

Bohm (1994) made a compelling proposal that body, emotion, intellect, and reflexive reactions based on memory together constitute 

much of our thought. Through repetition, emotional intensity, and 

defensiveness, reflexive thought becomes hard-wired in our consciousness. Bohm asserted that thought and knowledge are primarily collective phenomena—our belief in our own uniqueness and 

originality is often an illusion. Thus, he notes that flow of meaning 

among individuals is more fundamental than any individual’s particular thoughts. Cognitive psychologists have long recognized that 
C H A P T E R 3 Individuals, Society, and Conservation 65

A variety of colors of fallen leaves 

blanket the forest floor in a riparian 

area of the North Fork Quinault River, 

Olympic National Park. Photo by A. 

Wilson.

the mind works like a file cabinet; each significant new experience 

creates a folder of emotion and reaction; every subsequent similar 

experience opens that folder and reinforces the behaviors in it. As 

experience accumulates, it becomes more difficult to add folders (and 

perspectives) because there will be one with some similarity to the 

current event. A strong (positive or negative) experience that contradicts the information in the folder is required to create new reactions (ways of thinking). For example, space becomes place through 

experience, cultural transmission of meanings, and defining events 

or moments (Beckley 2003). Perhaps this is how the collective field 

trip is experienced—a positive social event, aimed at reconciliation, 

in an aesthetic, natural environment, ideally with one or more good 

interpreters of nature and people’s ways of thinking.

Experiences of the few can sway entire cultures when artfully 

expressed. We spend our lives immersed in stories—those in newspapers, books, television programs, plays, motion pictures, politicians’ 

speeches, ministers’ sermons—that entertain, inform, teach, and 

deeply move us (Simpkinson and Simpkinson 1993). These stories 

tell us “who we are and how we relate to the world.” The stories of 

the Kalahari Bushmen provide them with potent reminders of the 

way in which inner and outer, individual and community, and human 

community and natural world are inextricably linked. Even though 

it seems that the Western contemporary world finds it difficult to 

hear the “words of the ancestors,” African, Asian, Native American, 

and Scandinavian myths and fairy tales have provided a treasure 

trove from which great interpreters—Joseph Campbell, Bruno Bettelheim, Robert Bly, Clarissa Pinkola Estés, Michael Meade—relate 

to us our basic relationships with each other and the world. Roman 

Catholic biographies of saints tell stories of exemplary lifestyles in 

the face of adversity. In the Pacific Northwest, from Cougar, Washington, to La Grande, Oregon, small restaurants and country stores 

sell books and pamphlets on local history, logging, ranching, settlers, 

and Native Americans (see e.g., Trosper 1985, 1987, 1992, 1995; Wallace 1997, 1998). These stories instill local pride and belonging and 

reinforce cultural values through shared experiences. Native Americans sometimes refer to stories as a “map in the head,” a metaphor 

for finding the place that connects chaos and order (Peat 1993). 

Peat (1993) believes “science is the creation of stories that interpret the interconnectedness of the universe.” Examples range 

from Charles Darwin to John Muir to Aldo Leopold to Rachel 

Carson. Despite few having experienced the environments that led 

Darwin to his theories of evolution, Darwin’s metaphors are now 

established cultural messages. Compelling metaphors can combine 
66 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 13—The MyersBriggs Type Indicator and 

Herrmann Brain Dominance Assessment have long been used by 

organizations as a tool to encourage discussion about personality, 

temperaments, and preferences in 

the various ways of thinking. Both 

help to improve understanding of 

self and others, enhance communication, encourage teaching 

and learning, and build partnerships. Participants of collaborative 

management may consider using 

these helpful tools. 

For further reading:

 Keirsey, D.; Bates, M. 1984. 

Please understand me: character and temperament types. 

Del Mar, CA: Prometheus 

Nemesis Book Company. 

210 p.

 Herrmann, N. 1996. The 

whole brain business book. 

New York: McGraw-Hill. 

334 p.

Or visit the following Web sites:

 www.hbdi.com/

 www.myersbriggs.org/

with worldviews to provide a perspective of nature that may be either reinforced or found to be unsupportable in the experience of 

nature. The “tree of life” relates the common biological origins of 

all species, suggests kinship that requires ethical respect, and promotes the intrinsic value of all life. The “web of life” relates the value 

of biodiversity for human survival and an environmental ethic that 

produced ecological economics, utilitarian approaches to conservation, and the concept of interdependence. But more than culture 

(and mythologies), metaphors, experience, and science shape the 

four major views of the natural world that Regier (1993) identified: (1) the free-market economist who promotes development, (2) 

the environmental economist who practices conservation, (3) the 

naturalist preservationist who values ecosystem health, and (4) the 

extentionist preservationist who sees all species as equal and who 

values wilderness. 

Subcultural philosophies and individual preferences for particular ways of thinking (cognitive preferences) cause people to selfselect occupations and vocations and underlie the conduct of the 

sciences that inform various worldviews and influence the understanding that results from research. Both within the subculture of 

scientists and within culture as a whole, individuals exhibit preferences for thinking that readily accept some kinds of information and 

reject or discount other, often equally valid, kinds of information 

(Coulson and Strickland 1983, Herrmann 1996, Mintzberg 1975) 

(sidenote 13). Economists, engineers, and the “rational economic 

man” will seek, analyze, and apply hard data amenable to linear, 

reductionistic thinking. A sociologist, nurse, teacher, or musician 

will accept statements of feeling and qualitative evaluation of ethics and aesthetics more readily than the analytic, linear thinkers. A 

policeman, minister, and agency line officer will look to tradition, 

rules, regulations, and laws. Holling et al. (2002a) report that conservationists emphasize ecology and evolution (abstract integrative 

thinking that produces idealized states of nature) and ignore economics that emphasizes synergy, human ingenuity, enterprise, and 

flexibility. Economists and developers emphasize free market models (according to a narrow economic dogma emphasizing rational, 

linear thinking and analysis of a narrow set of variables) and ignore 

the uncertainties of nature. Sociologists and community activists 

place faith in community and social organizations (with a thinking 

that emphasizes care for people and interpersonal relationships) and 

presume nature presents no limits to the imagination and initiative 

of local groups. All these views are correct, but they are all partial, 

too simple, and lack an integrative framework (Holling et al. 2002a). 
C H A P T E R 3 Individuals, Society, and Conservation 67

Table 8—Five alternative views of nature—Balance leads to Malthusian determinism; anarchy leads to a conclusion that spatial heterogeneity is the critical ingredient for persistence in an unstable world.a

View Stability Processes Policies Consequences

Nature flat 	None 	Stochastic 	Random 	Trial and error

Nature balanced 	Globally stable 	Negative feedback 	Optimize, return 

to equilibrium

	Pathology of 

surprise

Nature anarchic 	Globally unstable 	Positive feedback 	Precautionary 

principle

	Status quo

Nature resilient 	Multiple stable 

states

	Exogenous input 

and internal feedback

	Maintain variability	Recovery at local 

scales or adaptation; structural 

surprises

Nature evolving 	Shifting stability 

landscape

	Multiple scales 

and discontinuous 

structures

	Flexible, actively 

adaptive, probing

	Active learning, 

new institutions

a Resilience leads to an emphasis on keystone species and key functional groups and abiotic and biotic processes; evolution leads to systems approaches. Sustainable relationships between people and nature require ecosystem resilience 

and a shift from command-and-control to adaptive management.

Source: Hollings et al. 2002a.

These contrasting alternative views of nature, like the metaphor of 

a group of blind men examining an elephant (each limited to a 

particular anatomical part) would be amusing if not for the consequences to nature, local economies, communities, and the spirit of 

individuals. 

Thus, it should be no surprise that experiential learning becomes 

essential in tempering worldviews based on thought. And group experiential learning may be the key to finding creative integration 

of worldviews in formulating pragmatic and potentially successful 

approaches to conservation (table 8). Political strategies of various 

groups (1) attempt to change the terms of political discourse, one 

emphasizing nature as natural resources, another nature as the human environment; (2) constitute tangible forums within civil society to use the communicative power of public opinion—yet some 

forums will be convened by offroad vehicle activists, others by environmentalists, and yet others by economic-development interests; 

(3) draw upon government fears of political instability—demonstrations, civil disobedience, and violence are being used routinely 

by diverse interests; and (4) create paragovernmental activity, such 

as the Forest Stewardship Council and the timber industry establishing competing sustainable forestry standards and certification, 

conservation groups and industry both offering school curricula and 

extension services, and innumerable other approaches (Schlosberg 

and Dryzek 2002).
68 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 14—“Pathologies 

of regional resource management”—Northern California 

provides a rich tapestry of conflicts and pathologies in regional 

resource management and the 

emergence of a variety of communal solutions to environmental 

problems. Judi Barr (1994) tells 

her personal, tragic story of an 

activist crippled by a car bomb, 

but resolute in seeking justice in 

conflicts over redwoods. David 

Harris (1996) relates a story 

of Pacific Lumber Company’s 

hostile takeover and the resultant 

social and ecological turmoil 

caused by a shift from stewardship to exploitation. Ted Simon 

(1994) presents a case history 

replete with differences in culture, 

worldviews, politics, cognition, 

and personality in his story of 

Richard Wilson’s personal evolution from republican-patricianentrepreneurial rancher to community activist and conservation 

group leader (and eventually head 

of the California Department of 

Forestry) in his fight to save his 

ranch, Round Valley, and Covelo, 

California, from inundation as a 

water reservoir for Los Angeles. 

Simon brings a perspective eye, a 

sympathetic ear, and a decentered 

view to his subjects. His ability 

to perceive and describe compassionately the diverse characters in 

conflict in his story arose, perhaps, 

from his own personal evolution 

during a 4-year exploration of the 

length and breadth of the major 

continents of the world, alone, 

on a motorcycle (Simon 1981)—a 

journey during which his very 

survival necessitated acceptance, 

understanding, and adaptation 

to diverse cultures, religions, and 

individuals.

Incorporating critical reviews of historical interactions between 

people and nature at regional scales helps to extend the collective 

experience. Holling et al. (2002a) recounted four resource management failures: (1) collapse of fisheries in spite of widespread public support and highly developed science; (2) moderate stocking of 

cattle in semiarid rangelands that increased vulnerability to drought; 

(3) pest control that led to pest outbreaks becoming chronic; and 

(4) flood control and irrigation that incurred large economic and 

ecological costs. They concluded that the observed pattern of failure 

is one of resources appropriated by powerful minorities capable of 

influencing public policy to provide perverse subsidies that lead to 

resource depletion. The fundamental cause of failure is the political 

inability to deal with the needs and desires of people and with rent 

seeking by powerful minorities. Contributing causes are the narrowly focused ways that many, including scientists and analysts (especially ecologists, economists, and institutional analysts), perceive 

and study the natural world and provide unintended opportunities 

for political manipulation (sidenote 14). The fundamental cause is 

the “Pathology of Regional Resource and Ecosystem Management,” 

and the contributing cause is the “Trap of the Expert.” The former 

reflects the detachment from nature, place, and communities; the 

latter, ways of thinking. Holling et al. (2002a) added that obstacles 

arise from multiple, competing scientific perspectives and disciplinary hubris. 

Three philosophical positions underlie the accumulation of new 

knowledge known as science (Czech 2001): (1) realism, wherein the 

goal is to build knowledge of reality by following a clear rationale 

and subjecting it to critique; (2) idealism, wherein paradigms provide knowledge independent of reality; and (3) empiricism, wherein 

all knowledge originates in experience. Thus, a holistic philosophy 

of science requires the use of ontology, epistemology, logic, aesthetics, and morals (Czech 2001). Pure science is the search for knowledge for its own sake. Moral science, however, is accountable to the 

society that hosts it. The moral philosophy is that science should 

seek knowledge with a goal of improving the human condition, a 

consideration often overlooked. Humans, however, have a great appreciation for the aesthetics of other species, and the majority of 

Americans approve of the Endangered Species Act. Americans 

value conservation of other species as highly as economic growth 

or property rights. Thus, public institutions have an obligation to 

gather knowledge and take action to protect species from endangerment. Knowledge, however, transcends scientific knowledge and 

includes mathematical proofs, memorized experiences, common 
Cerebral Thinking

Emotional Thinking

(Upper left) (Upper right)

(Lower left) (Lower right)

Analytical

Regulatory

Integrative

Humanistic

C H A P T E R 3 Individuals, Society, and Conservation 69

Figure 9—Ways of thinking: each 

person uses all four ways, but generally 

emphasizes one or two in decisionmaking (adapted from Herrmann 

1996).

sense, intuition, metaphysics, and art as a way of knowing. Camille 

Paglia (1990), e.g., demonstrates the knowledge in art. Scientists, 

technologists, and managers do not have a monopoly on knowledge, 

cognition, or intelligence. Traditional ecological knowledge of indigenes includes a wealth of local observations at the level of populations and species over long periods that produce holistic perceptions 

of the natural environment and the place of humans in nature (Ford 

2001). Conventional science usually is limited to investigations in 

a small area during a limited time and, thus, is not well suited to 

recognizing, analyzing, and responding to emergent properties of 

complex systems. Thus, various sources of knowledge are required 

before an integrated view of a complex and self-organizing system 

such as an ecosystem or a society can be gained.

People have preferences in their ways of thinking (fig. 9) that 

influence the way they perceive the world or any particular problem, 

information they will assimilate readily, and the processes by which 

they arrive at decisions (Carey 1997). For example, an engineer (analytical thinker) might prefer a modeling process using a linear programming model, whereas a holistic health care consultant (peopleoriented thinker) might prefer a group decision process including 

the patient. The ways in which worldview and cognition affect how 

people perceive issues around biodiversity were amply illustrated at 

the proceedings of the 1982 national symposium on how to implement the diversity provisions of the National Forest Management 

Act (NFMA) (Cooley and Cooley 1984). The former Chief of the 
70 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

USDA Forest Service, Max Peterson (1984), recalled the diversity 

provisions of NFMA as arising simply from concerns about loss of 

flowering dogwoods from roadsides in Arkansas because of conversion of hardwood forest to conifers. This not only illustrates the importance of forest aesthetics to the public, but also the downside of 

an analytical, linear thinking style that is especially prominent in engineers and traditional economists (Carey 1997). This thinking style 

can be quite reductionistic. In this case, the major impetus for the 

NFMA seems to have been forgotten. The Monongahela clearcutting 

controversy resulted in litigation that halted timber harvesting on 

national forests, produced draft prescriptive legislation that would 

direct Forest Service management activities, and led to NFMA as an 

alternative to the prescriptive legislation. Another high-level career 

Forest Service employee recalled that NFMA was actually a combination of a House bill requiring diversity of tree species and a Senate 

bill requiring a diversity of plant and animal communities—protecting biological diversity as a means of ensuring that biological 

systems can respond to unanticipated changes as an insurance policy 

(MacCleery 1984a). Orie Loucks, an academician at the conference, 

traced the concern about diversity to the writings of Aldo Leopold 

and subsequent research by Simpson (1949), Preston (1948), Loucks 

(1970, 1984), Whittaker (1972), Terbogh (1974), and Pielou (1975). 

An environmentalist recounted the history of diversity requirements in other legislation including the Multiple Use Sustained 

Yield Act, National Environmental Policy Act, Endangered Species Act, Sikes Act, and Resource Policy Act and in the Council 

on Environmental Quality 1980 report that warned of imminent 

large-scale species loss (Kirby 1984). Another academician traced 

the American history of land use changes wrought by people and 

the effects on diversity, including the mythology of pristine nature 

and the extinctions of Pleistocene fauna by people invading North 

America (Golley 1984). A third academician recounted a detailed 

historical account of events leading to NFMA citing the litigation 

Izaak Walton League vs. Butz that led to the Monongahela decision, the subsequent prescriptive legislation drafted by Senator Jennings Randolph of West Virginia, the wrangling in the House to 

produce a bill without a diversity provision, and, finally, the efforts of 

Senator Hubert Humphrey of Minnesota (Humphrey Bill, Senate 

Bill S3091) (Webb 1984). Yet a fourth academician described three 

origins for the concerns about diversity in NFMA (Cooper 1984): (1) 

Aldo Leopold’s land ethic; (2) ecologists’ concerns about the relationships between diversity, especially functional diversity, and system stability; and (3) the concerns of the conservation community 
Domains of Reality

Interior Exterior

Individual

Left Right

Social or

communal

Intentional Behavioral

Social

(system)

Cultural

(worldspace)

C H A P T E R 3 Individuals, Society, and Conservation 71

Figure 10—Domains of reality or 

different ways of knowing about the 

world: The right half of the quadrants 

can be seen and described in It language. However, the left half cannot be 

seen and must be described in I or We

language. The left half must also be 

interpreted in the context of worldspace and intentions (adapted from 

Wilber 1995).

for rare and endangered species and community types. He left out 

the concerns about aesthetics and dogwood and the original impetus, the concern of West Virginia hunters about their favored 

game animals. A fifth academic ecologist expanded the concept to 

six aspects (Odum 1984): (1) diversity above and below the species 

level, genetic diversity, and functional diversity; (2) landscape-level 

diversity and concerns about monocultures; (3) diversity and stability, resistance, and resilience; (4) invisible diversity below ground; 

(5) diversity and the life support value of forests; and (6) diversity 

and urbanization. A Forest Service scientist raised similar concerns 

(Franklin 1984). Managers at the symposium searched for operational meanings and baselines (MacCleery 1984b; Salwasser et al. 

1984a, 1984b). No one examined the social evolution of conservation concepts beyond those of the United States, the various cultural 

values centered on diversity, or the spiritual values that even ancient 

cultures found in natural diversity. 

Individuals usually emphasize one or two of the four major cognitive preferences; very few people use all four equally. Thus, each 

person has a degree of self-limited access to information. The combination of cognitive preferences and subculturally (e.g., scientific 

vs. religious vs. agrarian) defined ways of knowing (fig. 10) leads to 

massively incomplete understanding of problems and their solutions. Interpersonal and intercultural differences can lead to failures in communication and cooperation, polarization, and litigation. 

Simon (1994) provides an example (see sidenote 14). Groupthink 
72 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

( Janis 1982) commonly arises in homogeneous groups and appears 

to have dominated the Forest Service through much of its history 

(Kennedy 1988). Cooper (1984) accurately prophesized: “Inevitably 

somebody is going to ask the Forest Service if it has done what the 

law requires ... So, despite the fact that forest managers do not want 

more direction, I think they are eventually going to have it.”

Despite differing worldviews and different preferences for one 

or more of the various ways of thinking, a variety of conclusions 

emerged from the national diversity symposium (Cooley and Cooley 1984) and can be viewed, in my opinion, as currently still applicable (shown below in regular type) or as mistaken in the long run 

(italics):

 Providing for diversity is essential to maintain flexibility and 

options for the future.

 Research is needed to provide a stronger conceptual basis and 

expanded database for conservation.

 Baselines for diversity should be identified at national, regional, 

and local scales.

 Diversity indices should be used as analytical tools, not to define diversity (universally accepted definitions still elude us).

 Diversity should be treated as an effect of management, not as an 

objective (biodiversity is now a major objective).

 Certain guidelines (e.g., managing dead wood components) 

should be formalized.

 The existing process adequately considers diversity in multiple-use 

planning (plans and regulations are still being challenged and 

revised in efforts to address biodiversity).

 Information to provide for diversity should be integrated to 

provide a better database.

 Functional diversity, especially that of faunal communities associated with forest floors and soils, should be given greater attention.

Even so, the view of diversity as a relatively trivial concern about 

flowering dogwoods prevailed as agency policy as Cooper (1984) 

prophesized. The people first asked, then sued, and continued to provide stronger and stronger direction to an agency that did not want 

direction. A recent attempt to formulate a framework for national 

forest management (USDA Forest Service 2000) identified four key 

concepts: (1) sustainability as the overall goal in accordance with the 

Multiple Use Sustained Yield Act; (2) extensive cooperation, and 

collaboration with public and private entities; (3) integrating science 
C H A P T E R 3 Individuals, Society, and Conservation 73

more effectively into the planning process; and (4) eliminating burdensome analytical requirements. This new planning rule affirmed 

ecological, social, and economic sustainability as the overall goal; 

maintenance and restoration of ecological sustainability as the first 

priority; greater public collaboration with expanded management 

choices, trust building, conflict management, and informed decisionmaking; a commitment to the viability of all species; regional 

assessments; and monitoring. However, this rule also attempted to 

codify one conservation philosophy, conservation biology, and has 

already been rejected. It may well be past the time when centralized 

rule making for natural resources management is acceptable to the 

public as a whole. The public has a “pervasive distrust of the agency” 

and is disillusioned because of the inadequacy and inappropriateness of previous planning and the resultant adversarial atmosphere 

with its extremist positions (Committee of Scientists 1999).

Critical Theory and Green Political Thought

For the first time, we are faced with the collective responsibility for 

the consequences of our actions on a global scale. In this new millennium, loss of biodiversity has accelerated, global climate change 

is advancing, and social institutions are not attempting to develop 

an ecologically sustainable society. The social learning capacity of 

society must be used if we are to respond globally to ecological degradation. We must develop ecological norms and an ecological ethic 

that can work within a pluralistic, postmodern world, and we must 

accommodate a wide range of cultural viewpoints with their conflicting notions of what is profane and sacred, what is truth and 

heresy, and what it means to be human (Brulle 2002, Dryzek 1997). 

Is this hope utopian? How can we do this? 

Brulle (2002) argues that critical theory can be used to good 

purpose here. Jürgen Habermas developed a Theory of Communicative Action. In previous historical eras, justification for ethics was 

based in metaphysics and spiritual belief systems that produced a 

philosophical definition of the good life. Modern society, however, 

has produced a pluralism of individual lifestyles and forms of life 

that collectively maintain a multiplicity of ideas of the good life and 

a breakdown of classical ethics. In other words, today there is no 

one uniquely privileged mode of life. Habermas’s analysis of language suggests that norms of speech use define rational, universal 

moral principles, and, thus, might help identify these principles. 

Furthermore, communication creates and maintains social order; 
74 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

thus, critical analysis of language can help us move toward a more 

civil society. Truth, normative adequacy, and sincerity enable communication and tie the individual’s personal identity to the interaction. Thus, Habermas linked rationality, law, and constitutional 

democracy. Brulle (2002) quotes Habermas: “The only regulations 

and ways of acting that can claim legitimacy are those to which 

all who are possibly affected could assent as participants in rational 

discussions.”

Legitimate expectations of reciprocal behavior in a modern, 

pluralistic society now take the form of rational law, and law can 

no longer be legitimated by metaphysical arguments. Legitimate 

law emerges only from the discursive opinion and will of equally 

enfranchised citizens. Citizens must see themselves as authors of 

the laws to which they are subject, and they must see public decisionmaking as a process of self-determination through open and 

rational discourse. Thus, even the normative content and structure 

of a representative democracy arise from the structure of linguistic 

communication. All citizens have basic individual rights: freedom 

of speech, equal protection under the law, and freedom of political 

association. All have basic sociological and ecological rights to the 

provision of living conditions. 

Critical theory is a sociological inquiry that provides critical 

assessment of existing social institutions compared to standards 

of rationality; it is a procedure that does not determine what is a 

moral, ethical, good life or ethical standards for treatment of nature. Critical theory recognizes that there are many different forms 

of reasoning about the value of nature that inform multiple ethical 

arguments—there is no one universal argument for preservation of 

nature that will fit all cultures. For example, critical theory concludes 

that ecological rights are concerned solely with protecting aspects of 

nature strictly for human utilitarian purposes, but no more than this. 

Ecological ethics are a concern about what is a good life and outside 

critical theory. Democratic decisionmaking considers treatment of 

nature as a significant ethical concern because it is clear humanity 

and nature are interdependent and that the dependence of nature 

on our actions is evident. Ecology can provide information on impacts on the natural environment but holds no special competence 

in providing moral or aesthetic reasoning. There are limits to the 

use of science and biology in regard to human ethics. Furthermore, 

without fixed natural categories, fixed boundaries between nature 

and culture, fixed human nature, and fixed overall direction in the 

life process, it is impossible to make nature into a source of ethical 

and political prescriptions (but see Wilber 1995 below). 
C H A P T E R 3 Individuals, Society, and Conservation 75

Big leaf maple. Photo by T. Wilson.

Critics say critical theory cannot adequately integrate concern for nonhuman 

nature because it only considers development 

of norms between humans. Robyn Eckersley provided a persuasive critique (Brulle 

2002). Critical theory has benefits for human affairs—public participation enhances 

deliberations about preserving nature and 

community decisions should be democratic. 

But there are limits to its use—critical theory 

does not restructure ground rules of decisionmaking to provide any explicit recognition of 

nonhuman interests, it fails to justify preservation of species without utilitarian value, 

and its aesthetic values are selective and anthropocentric. Eckersley suggests that critical 

theory needs to develop a concept of nature as an end in itself, an 

expanded ethic that includes nonhuman needs, a science-informed 

moral line of argument, a recognition of the autopoietic intrinsic 

value theory that all organisms have self-directedness, and a principle for inscribing ecocentric norms into procedures of discourse as 

a matter of morality and justice (e.g., the precautionary principle).

Brulle (2002) rebuts the criticisms. All our knowledge of nature 

is socially constructed, and there is no authentic human representative of nature to speak for those nonhuman species. Seeing nature as 

a self-maintaining system is based on an application of systems ecology to construct a philosophy of nature that Brulle feels was robustly 

critiqued by evolutionary ecologists in the 1980s and 1990s (but see 

Gunderson and Holling 2002, Wilber 1995). Systems theory claims 

nature evolves through generation, diffusion, and selective retention 

of random mutations in a process of continual adaptation. Critics 

of systems ecology say nature is a chaotic system not self-regulating 

and thus one cannot use science to tell what a natural community 

or ecosystem is, never mind define what the essence of nature really is. Brulle (2002) states that the autopoietics of nature and the 

endowment of agency to nature is not a universal and objective idea 

grounded in ecologic science, rather it is a social construction of nature that suits a particular political aim; therefore, preserving nature 

means preserving a particular construct of what nature is supposed 

to be. Systems theorists (e.g., Wilber and Holling), however, have 

gone far beyond the arguments that Brulle rebuts to consider the 

physical Earth, nature, economic systems, and societies as parts of 

larger wholes. Indeed, Brulle states the artificial dichotomy between 
76 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

humans and nonhuman nature is scientifically and historically inaccurate. He says: “Healing the rift between human beings and the 

natural world ... is not a matter of joining what was once put asunder, but of getting the relations between human beings right first” 

(Brulle 2002). Thus, there is no necessary conflict between ecocentric norms and critical theory. However, Wilber (1995) insists on an 

even broader, decentered view—that of the holarchy (see below).

The Role of Place in Conservation

A sense of place plays a fundamental role in the ways people conceptualize, practice, and disagree over conservation. Strong and direct 

connections exist between self-identity, place, and how individuals 

perceive and value the environment (Beckley 2003, Cheng et al. 2003, 

Mitchell et al. 1993). Places are the fundamental means by which we 

make sense of the world and through which we act. Social group 

identity and place are tied together and influence the group strategic behavior in natural resources politics. Thus, choice of geographic 

scale of place is a strategic key element of natural resources decisionmaking because conservation politics is as much a contest over 

place meanings as a competition among interest groups over scarce 

resources (Cheng et al. 2003), at least between local interest groups. 

Places invoke rich and powerful emotions and sentiments that influence how people perceive, experience, and value the environment; 

the feelings evoked are stored as “felts” and become integral parts 

of thought. Place-based stories recall and reinforce such felts and 

thoughts. The strong emotions and thoughts associated with places 

require even more attention on the part of professional managers 

than conflicts associated with competition for use of scarce resources; the interactions with the public quickly move into psychological 

and social contracting (Rousseau 1989), as opposed to legal contracts 

associated with competitive bidding for timber sales. Violation of a 

social contract is much more serious than cancellation of a business 

contract, and violation of psychological contracts can do irreparable 

harm to relationships (Levinson et al. 1962). Because places are not 

merely physical backdrops of human activity, but rather help people 

find order and meaning in the world, community-based collaborative partnerships are especially important in encouraging people of 

diverse backgrounds and opposing perspectives to work together to 

find common ground and common vision. Thus, a politics of place 

emphasizes place-based collaboration and problemsolving, whereas 

a politics of interest emphasizes legislative/agency/command-and-
C H A P T E R 3 Individuals, Society, and Conservation 77

control planning influenced by powerful coalitions. Cheng et al. 

(2003) offer these propositions:

 People’s perceptions and evaluations of the environment are expressions of place-based identity and deeply personal connections with history and meaning.

 People perceive and evaluate the environment as different places 

rather than an assemblage of individual biophysical attributes.

 Social groups that seemingly emerge around using, protecting, 

or altering the physical attributes of a location may be engaging 

in more fundamental processes of assigning significant social 

and cultural meanings to that place.

 People’s evaluations of, and responses to, conservation proposals 

are influenced by their identification with social groups organized around particular meanings of the places involved.

 Groups intentionally manipulate the meanings of places, hoping to influence the outcome of conservation controversies.

 The geographic scale of a place can change people’s perceived 

group identification and, therefore, influence the outcomes of a 

natural resource controversy.

Attachment to place is based on the specific attributes of that 

place (e.g., community attachment, recreation-site attachment). Attachment influences public land management, regional economic 

development, and wilderness preservation (Beckley 2003). Rural 

residents’ attachments to their communities include attachments 

to the geological, biophysical, and landscape attributes of their regional ecosystem. Attachments of visitors to rural areas include sociological (rural residents, cottage owners, recreationists) as well as 

the biophysical characteristics of the place. Thus, the human values 

in attachment to place have tremendous consequences for policy 

issues in that people make “irrational” decisions to stay in regions 

with failing economies (Simon 1994 provides a vivid example; see 

sidenote 14). Whereas some people are attracted to and attached 

in a positive sense to a community or landscape, others are stuck in 

place—attached in a negative sense, because they lack the social network, specialized ecological knowledge, or marketable labor skill to 

survive anywhere else. Attachments to place are complicated; topdown centralized decisionmaking is extremely problematic because 

it is direction from those who are unfamiliar and empirically uninformed, making application of generalized principles to the specific place—a recipe for unmitigated disaster (Beckley 2003). The 

sustainability of a community or place has much more to do with 
Attachment to place

Time spent in place

High

Low

Low High

Travelers

One-time visitor

Occasional visitor

Vacation home

Repeat visitor

78 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 11—Time spent in place by 

different types of users (X-axis) may 

influence attachment to that place 

(Y-axis). Hypotheses about the timeattachment relationships made are (1) 

degree of attachment can be quantitatively measured; (2) degree of attachment varies with sociocultural factors, 

ecological factors, landforms, and 

cover types; (3) attachment changes 

with positive and negative changes 

in ecological and sociological factors; 

(4) degree and nature of attachment 

varies with size of unit of analysis; (5) 

attachment is a function of the length 

of time; (6) attachment is a function 

of cultural background; (7) attachment 

is a function of breadth and depth of 

knowledge; (8) attachment is a function of the nature of knowledge; and 

(9) degree of attachment reflects positive affective attachments (magnets) 

versus neutral or negative contexts 

(anchors) (adapted from Beckley 

2003).

people’s attachment to it than with standardized indicators of social 

sustainability.

Communities and Conservation

Community attachment implies an attachment to a defined geographic space, but there are also communities of interest (Beckley 

2003). Communities of interest are bound by shared values or interests rather than shared space. Sociocultural attachments are interactions of length of residence (fig. 11), position in social structure, 

and stage in human life cycle. Attachments are stronger to more 

democratic and tranquil places than to repressive places with social 

strife; but beyond security concerns, attachment is a very complex 

phenomenon. 

Human migrations are adding to the complexity of conservation policy (McCool and Kruger 2003). Rural areas in many parts of 

the Western United States had dramatic population growth in the 

late 20th century, fueled by environmental amenities, deteriorating 

urban conditions, and back-to-the-land movements. This growth 

stressed the capacity of rural communities. Amenity migrants often 

developed stronger attachments to place than long-time rural residents (McCool and Martin 1994). But at the same time, USDA Forest Service District Rangers and other agency high officials spent 

less time in rural communities and were relocated during downsizing and consolidations into larger communities distant from 
C H A P T E R 3 Individuals, Society, and Conservation 79

Sidenote 15—Shindler et al. 

(2002) asserted that (1) most people believe sustainable ecosystems 

are desirable; (2) many believe it 

is possible to supply forest products and maintain the integrity 

of the forest; (3) people expect 

managers to produce multiple 

benefits; (4) people know what 

they want (clean air and water, 

affordable wood products, decent 

jobs, recreation, scenic vistas), but 

managers frame choices poorly; 

and (5) people support a balanced, 

ecologically responsible approach 

to forest management.

the forest (­McCool and Kruger 2003). This restructuring seems to 

have reversed the processes of broadening discourses and changing 

mindsets of agency officials in response to increased public contact 

required by the National Environmental Policy Act (Carey 1997) 

and led to increased contact and conversations with agency peers 

and neighbors and community members not necessarily involved 

in conservation issues and matters of place. Migration raises other 

important considerations (McCool and Kruger 2003). For example, 

amenities are increasing in importance in rural areas and public 

lands offer environmental amenities. In addition, underrepresented, 

yet growing numbers of minority groups may have different wants 

and needs than earlier participants in conservation conflicts. 

Communities are especially important in conservation because 

they are at the front line of stewardship and sustainability and represent collections of interests and concerns that are demanding more 

meaningful roles in conservation planning (Kruger 2003). Public 

acceptance is essential to every conservation decision made by a 

public agency (Shindler et al. 2002). The reasons social acceptance is 

important include (1) conservation decisions are rarely about applying objective science to a specific event; (2) citizens have a right of 

consultation about the conservation of public resources; () absence 

of public understanding and support makes it difficult to implement 

any decision in a democracy, especially when the public is pluralistic and highly differentiated (sidenote 15); and () social acceptance 

provides opportunities for discussion and change. Local communities of place and attached communities of interest are where the 

“rubber meets the road.” Achieving social consensus requires public 

places to discuss and learn, opportunities for citizen participation, 

and trust building. Forums are needed for working through shared 

community values about fairness. Citizens do not trust conservation 

agencies—they doubt their sincerity and credibility, and they deeply 

distrust experts and institutions. To rebuild trust, citizen-organization interactions must be based on inclusiveness, sincere leadership, 

innovation and flexibility, early commitment and continuity of commitment, sound organizational and planning skills, and efforts that 

result in action (Shindler et al. 2002). A key is genuine dialogue. 

Interviews with people in Arkansas, California, Oregon, Colorado, 

Missouri, Montana, New Mexico, South Dakota, Tennessee, and 

Wyoming, despite generally cordial relationships between the USDA

Forest Service and local communities, stressed the need for agencycommunity relationship building, funding and legal authority for 

relationship building, training in relationship building for Forest 

Service employees, and cultivation of intra- and interagency working 
80 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

A mouse-eye view of the canopy in 

an old-growth forest on the Olympic 

Peninsula. Photo by T. Wilson.

relationships (Frentz et al. 2000). Collectively, these studies suggest 

an urgent need for the application of organization development theory and practice to conservation collaborative management, including sensitivity training, appreciative inquiry, conflict management, 

facilitating group dynamics, and a whole host of other well-developed methods for effecting change, bringing about transformation, 

and extracting creativity from conflict (French et al. 1994).

Social and Personal Evolution

Developing a common vision means moving away from polarized, 

position-based thinking, adversarial and litigious processes, and 

win-lose or compromise solutions that leave major dissatisfactions 

unresolved. “What we need is a collective dream large enough to 

encompass and transcend all our small individual dreams in a way 

that gives them meaning and unity” (Maser 1994). Collaborative 

management requires an informed and supportive public. It requires 

institutions that value justice, equity, decentralized collaborative 

decisionmaking, and pragmatic problem solving (Wondolleck and 

Yaffee 2000). It requires scientists who are willing to engage humbly 

in collaborative learning and facilitate collaborative management 
C H A P T E R 3 Individuals, Society, and Conservation 81

Sidenote 16—Maser et al. 

(1998) listed Erik Erikson’s eight 

stages of human development: 

 Trust vs. mistrust 

 Autonomy vs. shame and 

doubt 

 Initiative vs. guilt

 Industry vs. inferiority 

 Identity vs. identity confusion

 Intimacy vs. isolation

 Generativity vs. stagnation

 Integrity vs. despair

Sidenote 17—Maser et al. 

(1998) said a resident community 

serves five purposes: (1) social 

participation that produces self 

worth, safety, and shared values; 

(2) mutual aid in time of individual and family need; (3) economic 

production, distribution, and consumption that provides jobs and 

commodities; (4) socialization, or 

educating people about cultural values and norms; (5) social 

control, the means for maintaining cultural values and norms. 

Resident communities can be 

damaged by vested local-internal 

interests and by outside interests 

(overharvesting by outsiders, corporate clearcutting, and temporary government employees).

by providing relevant theoretical, empirical, and pragmatic science. 

Collaborative management requires the purpose of consensus; willingness to reveal, listen, and understand; and stamina to do arduous 

work. Both knowledge and emotion are shared through communication (tone of voice, body language, and attitude). Every person has 

the right to simplicity and clarity in communication and an obligation to communicate simply and clearly (Maser et al. 1998). Yet, the 

ability to communicate simply and clearly is not always easy, and 

it requires hard work. Social sustainability—the civil society—requires individuals to undergo personal growth through a shift in 

consciousness from self-centeredness to other-centeredness (Maser 

et al. 1998) (sidenote 16), or as Wilber (1995) shows, decenteredness 

(see sidenote 14). Care and respect for each other is essential—“be 

gentle with one another, be gentle with nature, be humble” (Maser 

1994). Collaborative management requires individuals to develop 

and actualize both their autonomy and their communality. In other 

words, individualism is good, bring it to the table, but set aside ego 

and strive for the common good. An aspect of communality important in collaborative management is a sense of community—a group 

of people with shared interests living under and exerting some influence over the same government in a particular locality and having 

a common attachment to that physical place and its social environment. A true community involves a sense of place, a history, and 

trust (Maser et al. 1998) (sidenote 17): “For one’s community to be 

sustainable and our democracy to be lasting, we must individually 

and freely be willing to recognize and abide by the common good in 

our decisionmaking.” However, there are communities of place and 

communities of interest that can be in competition. For example, 

the goals of the water-needy communities of interest in southern 

California conflicted greatly with the river-based communities of 

place in northern California. This is particularly true of federal lands 

where national, regional, and local interests abound. Both communities must be participants in the collaborative management process. 

An overarching framework is needed for progress in reconciling diverse views, values, and interests.

Frameworks—In a systems, holarchic view, there are three great 

realms of evolution: matter, life, and mind (Wilber 1995). Most of us 

are familiar with Darwinian evolution. Systems thinkers recognize 

evolution as the increasing differentiation, integration, structural organization, and complexity that offsets the Second Law of Thermodynamics, in other words, the forces that promote order versus those 

that lead to disorder. Theorists call this evolution the self-organizing 
82 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

system. To be part of a larger whole means that the whole supplies 

glue that holds the system together, glue not found in the isolated 

parts alone. Most of us are less familiar with the concepts of evolution of self and society. But many examples abound. For instance, in 

social systems, men seem to emphasize rights and justice in moral 

development as this social glue; women feel rights and justice must 

be supplemented with care and responsibility. It is easier to grasp 

social evolution than it is personal evolution within the greater social evolution. The following discussion recapitulates Ken Wilber’s 

(1995) systems view of evolution as it applies to matter, life, and the 

mind. He describes the processes of evolution of self, society, and 

culture.

Wilber (1995) distinguishes between two types of hierarchies 

that occur within human systems. Domination hierarchies are repressive and pathological; actualization hierarchies are integrative 

and maximize system (cultural, societal, and personal) potential. The 

cure for a pathological hierarchy (e.g., a machine bureaucracy) is an 

actualization hierarchy (e.g., intentional collaborative management), 

not heterarchy (multiple use with uses in different places) that is just 

heaps of uses, not wholes of integrated uses. In a heterarchy each element contributes equally, but separately to the health of the whole 

within each level of the hierarchy. Heterarchies have differentiation 

(different uses) without integration. Holarchies, on the other hand, 

have differentiation with integration that brings a common and 

deeper purpose. Actualization involves a ranking, or subjective valuation, of increasing holistic capacity. Ranking is disturbing to believers in extreme equality and autonomy—they consider value ranking 

equivalent to oppression. Finding value in the world, however, is 

inherent in the human situation; qualitative distinctions are built 

into human orientation. Indeed, to deny value is in itself a value; denying ranking is in itself a ranking. Thus, contexts and frameworks 

produce values and meanings and may produce the sense that some 

actions, lifestyles, and ways of feeling are higher than others more 

readily available to us. This provides us with informed choice. Affirming life and freedom by repudiation of qualitative distinctions may 

be motivated by the strongest of moral ideas (freedom, altruism, 

universalism), but in reality is deep incoherence, self-illusion, concealing from oneself the sources of one’s own judgments.

In understanding systems, it is useful to remember that matter, life, and mind are all part of the same holarchy of integrated 

whole/parts (holons). Holons display fundamental capacities in constant tension that create a novel holon with emergent properties—a 

wider, deeper whole. In other words, each holon, e.g., a person, seeks 
C H A P T E R 3 Individuals, Society, and Conservation 83

to preserve his or her autonomy and rights (agency), counterbalancing autonomy with search for communion (participation, joining, 

and bonding). These are the Taoist principles of yin (communion) 

and yang (agency), rights vs. responsibilities, individuality vs. membership, personhood vs. community that are set against self-dissolution vs. self-transcendence. Dominance by any one of the tendencies 

is pathological. But it is key to recognize that each emergent holon 

transcends but nevertheless includes its predecessor; nothing is lost 

while much may be gained: development is envelopment, not succession. 

In nature, e.g., invasion of an abandoned agricultural field may set 

up a succession of biotic communities, one replacing another in a 

more or less predictable series. But development of a new Douglasfir forest following catastrophic destruction of an old forest, with 

its attendant biological legacies, sets in process a series of stages of 

forest development (envelopment), each stage encompassing the 

preceding stage, increasing differentiation and integration. Each developmental level produces greater depth (number of levels) but has 

less span (number of new components in the new level) and is not 

necessarily correlated with size (spatial extent). The variety of shrews 

in the forest floor is far less than the variety of insects they consume 

or the variety of organisms and detritus the insects consume. However, destroy any holon and all the holons above it are destroyed, but 

none of the holons below it. Destroy a biotic community (shrews) 

and that particular ecosystem is gone; but the insects and their food 

(lower level ecological systems) remain. Destroy all humans and the 

biosphere still exists but the economies and societies disappear. Destroy the biosphere and humans disappear. Thus, holons with less 

depth (fewer levels) are more fundamental, but less significant. Holons coevolve. The holon of the individual is inseparable from the 

social holon, defined by its own particular form and pattern. Evolution of holons has directionality: increasing differentiation, variety, 

complexity, and organization. All autonomy is relative, but relative 

autonomy increases with evolution. In systems language, attractors in basins of attraction pull the system to a future endpoint (the 

omega point). In the terminology of Holling et al. (2002b), basins of 

attraction determine alternate stable states of ecosystems. It should 

be clear that systems theory easily envelops and integrates the polarized views and false dichotomies of earlier theories of organization 

and succession of biotic communities.

Many of our conservation issues are due to fractured worldviews; we lack a common vision. We need a vision that encompasses and transcends our individual visions. A beginning lies in 

a holistic view of a three-level world. Level 1 consists of physical 
84 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

and physiochemical systems in the realm of matter; it forms the 

broad base of a pyramid. Level 2 holds the organizational levels of 

biological systems in the realm of life. Any level 2 holon embraces 

its entire level 1 world. Level 3 holds the organizational levels of sociocultural systems in the realm of society. The pyramid is narrower 

at the top (relative abundance decreases). Each holon within the 

pyramid depends on a whole series of intricate relational exchanges 

with the social environments of the same level of structural organization. The greater the depth of a holon, the more precarious its 

existence—fewer of them can be produced and maintained relative 

to the number of predecessors. 

In the evolution of the mind, the human brain emerges from 

the genetic, metabolic, and neural biosphere. Paul MacLean (1985) 

described the brain as composed of three physical parts: a reptilian brain (the brain stem that provides autonomic and instinctive 

behavior), a paleomammalian brain (the limbic system that controls 

visceral and emotional reactions), and neomammalian brain (the 

neocortex that supports language and logic and the self-reflexive 

mind). In the emergent, nonphysical realm of the mind, size (spatial extent) gives way to intention. The social environments of the 

human are family, village, town, city, and state. There is no compelling biological reason (reproduction of bodies) for organization at 

the village level and above, but these higher organizations provide 

the symbols and tools necessary for reproduction of culture through 

symbolic communication. Thus, with evolution, kinship gave way to 

cultureship as the brain remained unchanged for 50,000 years and 

cultural development proceeded from the mind.

Of course, with greater structural complexity, more things can 

go horribly wrong. Atoms do not get cancer, but animal tissues do. 

Evolution producing greater transcendence and greater differentiation can go too far and fail to adequately integrate the emergent 

differences into a coherent whole. Some theorists postulate that 

most of humankind’s problems came with the invention of farming. 

People began to alter the biosphere for their own gratification, created a written language that ensconced power in dogmatic text, and 

produced agricultural surpluses that led to economic control, slavery, 

and the subjugation of women. These theorists idealize the huntergatherer society; but that society was rarely egalitarian and often 

warlike. Wilber (1995) labels this kind of thinking as the “way-back 

machine looking for the Garden of Eden”—a thought process highly related to managing for the range in natural variation from some 

preagricultural period and mimicking stochastic disturbance processes. The problem was not the development of agriculture but the 
C H A P T E R 3 Individuals, Society, and Conservation 85

lack of integration and the development of dominator hierarchies in 

the evolution of agrarian societies.

Coincident with the external process of social evolution is the 

interiority of the evolution of the mind—from irritability to sensation, perception, impulse, image, symbol, and concept. The within

of things relates to consciousness, cognition, perception, and spontaneity. Karl Popper refers to the “making and matching” of new 

epistemological domains. Jürgen Habermas, in his studies of communication and the evolution of society, developed a Theory of 

Communicative Action with epochs of human evolution based on 

worldviews: archaic, magic, mythic, and mental (Brulle 2002). Thus, 

shared values constitute the exterior culture and worldview constitutes the interior of the social system. A shared cultural worldspace 

must be interpreted: What does it mean versus what does it do? 

Wilber (1995) gives the example of a Hopi rain dance as expressing 

a sacred connection with nature and a request (meaning) and producing social solidarity and cohesion (function). Meanings provide 

understanding; functions provide explanations. 

Subtle reductionism reveals four dimensions of interpretation 

(see fig. 10)—intentional, behavioral, cultural, and social developments—not the single dimension of materialistic and mechanistic 

function of gross reductionists. The interior is dialogical, dialectical, 

and empathetic with major issues related to meaning, interpretation, 

and sincerity (truthfulness). The external deals with propositional 

and empirical validity criteria that determine truth (Wilber 1995). 

Thus, thoughts have meanings to individuals that are sustained by 

a network of exterior norms and linguistic structures existing in 

a shared culture. In other words, a shared worldspace is necessary 

for communication of meaning among individuals. This raises the 

question of cultural fit of individual meanings and values with the 

culture that helps produce them. Background and culture allow individuals to form meaning, and relational exchange allows communication between people. Thus in the lower left quadrant (cultural 

worldspace), validity criteria are truth, truthfulness, and mutual understanding; in the lower right quadrant (social system), the criteria 

for validity relate to functional fit—what does it do? All this exists 

within a holarchy of value, beauty, meaning, motivation, understanding, intention, and consciousness. Using reductionism to suborn the 

interior (lower left) to the exterior (lower right) fragments worldviews and reduces individuals to role and function. However, the 

four quadrants can be usefully collapsed into three: the right two 

composing Karl Popper’s objective world of It, the upper left, the 

subjective world of I, and the lower left, the cultural world of We. 
86 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Colorful birds, such as this male 

rufous hummingbird, spark interest 

in wildlife and help connect people to 

nature. Photo by A. Wilson.

Jürgen Habermas then postulates the three validity claims of truth 

(It, objects), truthfulness-sincerity (I, subjects), and rightness-justice (We, intersubjectivity). Plato similarly identified true (objective, 

propositional truth), beautiful (the individual aesthetic), and good 

(cultural appropriateness and justice). Kant’s critiques are pure reason (It), personal aesthetic judgment (I), and practical reason (We). 

And, finally, the three jewels of Buddha: Dharma (It), Buddha (I), 

and Sangha (We). The key here, in terms of conservation, is that we 

cannot escape these three worlds—the objective (It), the subjective (I), 

and the social (We)—and their different claims to truth—propositional truth, normative rightness, and subjective truthfulness. Each 

can be exposed to evidence and checked for actual validity in collaborative learning environments. These are the three fundamental 

functions of language—Intentionality (It), Truth (I), and Rightness 

(We). Each can be exposed to evidence and checked for actual validity in collaborative learning environments. These functions form 

the basis for active, intentional management (AIM) and the use of 

intentionality in evaluating conservation plans (Carey et al. 1999c). 

Wilber (1995) concluded that before we can attempt an ecological healing, we must reach an individual understanding and mutual 

agreement on the best way to collectively proceed.

Human nature—Evolution of the three-part brain allowed the 

evolution of symbols and concepts in the mind and the 

evolution of the family group and tribe. Reconciling the 

differentiation of social labor (e.g., hunting) and nurturance of young produced the “familization” of the male, 

the single enduring task of all subsequent civilization. 

Although, Gilmore (1990) suggests that familization is 

but one part of a much more complex social phenomenon. Nevertheless, early female horticulturalists produced 80 percent of the food and shared considerable 

public power with men. With development of the plow 

and an agrarian society, males produced the bulk of the 

food and dominated the public sphere; even reigning 

deities switched from a Great Mother to a Great Father 

focus. Thus, sex-based differentiation resulted in dissociation that produced an extreme sexual polarization. It 

would be some time before a new integration of men 

and women could be conceived in an utterly new worldspace. Michel Foucault observed that people, when discontent with the present, seek some cheap archaism—an 

imagined form of past happiness (e.g., the early-agrarian 
C H A P T E R 3 Individuals, Society, and Conservation 87

Eden preceding the European settlement of North America)—devoid of dangers and inequalities (Wilber 1995). 

In the battle of worldviews, each stage of development transcends and includes, negates, and preserves its predecessors. So the 

major structures of all the worldviews—magic, animism, mythology, 

rationality, vision-logic—may exist together, or in part in various 

degrees of integration, in any one individual, any group, or even side 

by side, unintegrated, in society. The first major development with 

familization of men and conventional kinship relationships was a 

magical-animistic culture within which people used preoperational 

thinking that works with images, symbols, and concepts, but not 

complex values and formal operational thinking. Thinking emphasized representations of sensory objects in the external world, close 

to the body. Morally, people exhibited physical pragmatism and a 

naïve instrumental hedonism. Norms were expressed in terms of 

good vs. bad, right vs. wrong and interpreted as punishment, reward, and exchange of favor. This culture is described as magical 

because there was little differentiation between the mind and body, 

and mental images and symbols could be confused with physical 

events; mental intentions were believed to be capable of altering the 

physical world. This culture was animistic because physical objects 

were considered to be alive and to possess intentions of their own. 

Collective identity was with a common ancestor and personal identity was with a particular tribe (Wilber 1995).

The next development was the mythological culture—societies 

organized through a state that required a more abstract identity and 

an expansion of the world of gods. Mythology was enveloped in 

turn by the mythic-rational culture, which incorporated the purposive rationality of scientific and technical knowledge, the formal rationality of mathematics, and the interpersonal-practical rationality 

of morality and communication. The rationality added was formal 

operational cognition—thinking about thinking, reflecting on one’s 

own thought processes, transcending them, and taking a perspective different from one’s own, entertaining hypothetical possibilities, 

being highly introspective, and justifying thoughts and actions by 

reviewing reasons and evidence for one’s beliefs.

Empires produced modern states that formally recognized each 

other, the separation of church and state, the emergence of a global 

market economy, and the rise of rational culture. Egoic-rational 

thinking began more than 2,000 years ago, but reached fruition in 

16th-century Europe. Socrates said know thyself, look within; Cicero 

echoed “Cognosce te ipsum,” and later philosophers asked what is 

there to know and how can I know it? Religions did likewise—Jesus 
88 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

said the kingdom of heaven is within, and Buddha said penetrate 

yourself. These were radically new thoughts and marked a conceptual change from individuals as the roles they play in society to individuals as free subjects. Socially this was translated into (a) free 

and equal subjects under the law, (b) morally free subjects, and (c) 

politically free subjects (callouts 2, 3).

New integration brought women to the fore as public and historical agents. This integration, of course, allows both liberal and 

radical feminism as well as women’s special rootedness in the biosphere:

... A million years of rich tradition of the wise woman who 

feels the currents of embodiment in nature and communion 

and celebrates it with healing rituals and knowing ways of 

connecting wisdom that does not worship merely the agentic sun and its glaring brightness but finds in the depths and 

organic dark the ways of being linked in relationship, that 

puts care above power and nurturance above self-righteousness, that reweaves the fragments with concern, and midwifes communion and the unsung connections that sustain 

us each and all. And finds, above all, that being self is always 

being a self-in-relationship (Wilber 1995).

It bears repeating, that each development envelops and maintains preceding developments; the use of animism, magic, and 

mythology as “as ifs,” not literally, can be transcendental—the real 

function of mythology. In other words, a properly interpreted myth 

can help us get in touch with our roots and our foundations, including the archaeological layers that lead to our present awareness. We 

can gain new perspectives from the interpreted mythologies of ethnic groups other than our own, be they African, European, Asian, 

or Native American. They can become empowering, enriching, and 

energizing because they touch archetypal structures while simultaneously robbing them of their worldview. For example, The Men’s 

Movement, led by Robert Bly, played out myths in an “as if ” fashion, transcending them with rationality. Camille Paglia (1990), in 

her groundbreaking monograph, traces the evolution of the female 

persona in art over the ages and women’s historical and new public 

agency. Finally, Paul Ray (1996) documents the contemporary leadership of women in the emerging, integrative, transformational subculture that holds community and sustainability as primary values. 

Genuine spirituality is the primary measure of depth in worldviews. 

The depth of reason is the capacity for universal pluralism, insistence 
C H A P T E R 3 Individuals, Society, and Conservation 89

Reason is the stuff 

of collaborative 

learning and 

collaborative 

management.

on universal tolerance, grasp of global-planetary perspectivism, insistence on universal benevolence and compassion—a genuine spirituality.

The majority in rational societies tend to settle in mythicrational (including religious-rational and dogmatic-rational) worldviews, using the power of rationality to prop up a particular divisive, 

imperialistic mythology and an aggressively fundamental program 

of systematic intolerance. Thus originates much of the contemporary 

public discourse in the United States. A modern solution to these 

deharmonizing discourses is the democratic state with its all-important separation of church and state that removes the worldviews of 

the would-be pathological dominator holons from the organizing 

regime of society that is defined by a rational tolerance of everything 

but intolerance. This robs the mythic holons of their power to govern 

exclusively and to push their mythic-imperialistic expansionism via 

military means—but it does not always prevent them from agitating 

to tilt the state toward their own fundamentalist values as has happened so successfully in recent years. Where myths govern, military 

expansion is the rule (Wilber 1995). 

The rationality of a universal, noncoercive outlook produces a vision-logic, a system of seeking truth, the relations of idea within idea 

and truth within truth, all seen in the integral whole. Vision-logic 

can hold contradictions in the mind; unify opposites; and weave together what otherwise appears to be incompatible notions, negated 

in their partiality but preserved in their positive contributions. This 

is Reason, and it is the stuff of collaborative learning and collaborative management. The worldspace of vision-logic is existential. Vision-logic has integrative power, which requires an a-perspectival 

mind (open to all truths) vs. a rational-perspectival mind; in other 

words, no single perspective is privileged. Vision-logic produced the 

international labor movement—the only global social movement in 

history. The strength of that movement was its commitment; the 

weakness was its lack of spirituality. The green culture (see also Ray 

1996) similarly is potentially powerful but makes a similar mistake 

of reductionism. Its two central notions are (1) the sphere of the 

mind is part of the biosphere and (2) the web-of-life systems theory; 

they are, Wilber says, in the first, wrong, and the second, subtly reductionistic. A more integrative approach is needed; Wilber calls 

it Planetary Transformation. Gunderson and Holling (2002) offer 

the Panarchy theory. Global transformation is necessary to protect 

the global commons, regulate the worldwide financial system, and 

maintain a modicum of international peace and security.

(continued on page 94 )
90 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Callout 2—The Declaration of Independence

In CONGRESS, July 4, 1776

The unanimous Declaration of the thirteen 

united States of America, 

When in the Course of human events, it 

becomes necessary for one people to dissolve 

the political bands which have connected them 

with another, and to assume among the powers 

of the earth, the separate and equal station to 

which the Laws of Nature and of Nature’s God 

entitle them, a decent respect to the opinions of 

mankind requires that they should declare the 

causes which impel them to the separation. 

We hold these truths to be self-evident, 

that all men are created equal, that they are 

endowed by their Creator with certain unalienable Rights, that among these are Life, Liberty 

and the pursuit of Happiness. —That to secure these rights, Governments are instituted 

among Men, deriving their just powers from 

the consent of the governed, —That whenever 

any Form of Government becomes destructive 

of these ends, it is the Right of the People to 

alter or to abolish it, and to institute new Government, laying its foundation on such principles and organizing its powers in such form, as to them shall seem most likely to effect their Safety and Happiness. Prudence, 

indeed, will dictate that Governments long established should not be changed for light and transient causes; and accordingly 

all experience hath shewn, that mankind are more disposed to suffer, while evils are sufferable, than to right themselves by 

abolishing the forms to which they are accustomed. But when a long train of abuses and usurpations, pursuing invariably the 

same Object evinces a design to reduce them under absolute Despotism, it is their right, it is their duty, to throw off such 

Government, and to provide new Guards for their future security. —Such has been the patient sufferance of these Colonies; 

and such is now the necessity which constrains them to alter their former Systems of Government. The history of the present 

King of Great Britain [George III] is a history of repeated injuries and usurpations, all having in direct object the establishment of an absolute Tyranny over these States. To prove this, let Facts be submitted to a candid world. 

He has refused his Assent to Laws, the most wholesome and necessary for the public good. 

He has forbidden his Governors to pass Laws of immediate and pressing importance, unless suspended in their operation till his Assent should be obtained; and when so suspended, he has utterly neglected to attend to them. 

He has refused to pass other Laws for the accommodation of large districts of people, unless those people would relinquish the right of Representation in the Legislature, a right inestimable to them and formidable to tyrants only. 

He has called together legislative bodies at places unusual, uncomfortable, and distant from the depository of their 

public Records, for the sole purpose of fatiguing them into compliance with his measures. 

He has dissolved Representative Houses repeatedly, for opposing with manly firmness his invasions on the rights of the 

people. 

He has refused for a long time, after such dissolutions, to cause others to be elected; whereby the Legislative powers, incapable of Annihilation, have returned to the People at large for their exercise; the State remaining in the mean time exposed 

to all the dangers of invasion from without, and convulsions within. 

He has endeavoured to prevent the population of these States; for that purpose obstructing the Laws for Naturalization 

of Foreigners; refusing to pass others to encourage their migrations hither, and raising the conditions of new Appropriations 

of Lands. 
C H A P T E R 3 Individuals, Society, and Conservation 91

He has obstructed the Administration of Justice, by refusing his Assent to Laws for establishing Judiciary powers. 

He has made Judges dependent on his Will alone, for the tenure of their offices, and the amount and payment of their 

salaries. 

He has erected a multitude of New Offices, and sent hither swarms of Officers to harass our people, and eat out their 

substance. 

He has kept among us, in times of peace, Standing Armies without the consent of our legislatures. 

He has affected to render the Military independent of and superior to the Civil power. 

He has combined with others to subject us to a jurisdiction foreign to our constitution and unacknowledged by our laws; 

giving his Assent to their Acts of pretended Legislation: 

For Quartering large bodies of armed troops among us: 

For protecting them, by a mock Trial, from punishment for any Murders which they should commit on the Inhabitants 

of these States: 

For cutting off our Trade with all parts of the world: 

For imposing Taxes on us without our Consent: 

For depriving us, in many cases, of the benefits of Trial by Jury: 

For transporting us beyond Seas to be tried for pretended offences: 

For abolishing the free System of English Laws in a neighbouring Province, establishing therein an Arbitrary government, and enlarging its Boundaries so as to render it at once an example and fit instrument for introducing the same absolute 

rule into these Colonies: 

For taking away our Charters, abolishing our most valuable Laws, and altering fundamentally the Forms of our Governments: 

For suspending our own Legislatures, and declaring themselves invested with power to legislate for us in all cases whatsoever. 

He has abdicated Government here, by declaring us out of his Protection and waging War against us. 

He has plundered our seas, ravaged our Coasts, burnt our towns, and destroyed the lives of our people. 

He is at this time transporting large Armies of foreign Mercenaries to compleat the works of death, desolation and 

tyranny, already begun with circumstances of Cruelty and perfidy scarcely paralleled in the most barbarous ages, and totally 

unworthy the Head of a civilized nation. 

He has constrained our fellow Citizens taken Captive on the high Seas to bear Arms against their Country, to become 

the executioners of their friends and Brethren, or to fall themselves by their Hands. 

He has excited domestic insurrections amongst us, and has endeavoured to bring on the inhabitants of our frontiers, the 

merciless Indian Savages, whose known rule of warfare, is an undistinguished destruction of all ages, sexes and conditions. 

In every stage of these Oppressions We have Petitioned for Redress in the most humble terms: Our repeated Petitions 

have been answered only by repeated injury. A Prince whose character is thus marked by every act which may define a Tyrant, 

is unfit to be the ruler of a free people. 

Nor have We been wanting in attentions to our British brethren. We have warned them from time to time of attempts 

by their legislature to extend an unwarrantable jurisdiction over us. We have reminded them of the circumstances of our 

emigration and settlement here. We have appealed to their native justice and magnanimity, and we have conjured them by the 

ties of our common kindred to disavow these usurpations, which, would inevitably interrupt our connections and correspondence. They too have been deaf to the voice of justice and of consanguinity. We must, therefore, acquiesce in the necessity, 

which denounces our Separation, and hold them, as we hold the rest of mankind, Enemies in War, in Peace Friends. 

We, therefore, the Representatives of the united States of America, in General Congress, Assembled, appealing to the 

Supreme Judge of the world for the rectitude of our intentions, do, in the Name, and by the Authority of the good People 

of these Colonies, solemnly publish and declare, That these United Colonies are, and of Right ought to be Free and Independent States; that they are Absolved from all Allegiance to the British Crown, and that all political connection between 

them and the State of Great Britain, is and ought to be totally dissolved; and that as Free and Independent States, they have 

full Power to levy War, conclude Peace, contract Alliances, establish Commerce, and to do all other Acts and Things which 

Independent States may of right do. And for the support of this Declaration, with a firm reliance on the protection of divine 

Providence, we mutually pledge to each other our Lives, our Fortunes and our sacred Honor. 
92 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Callout 3—The Bill of Rights

Congress of the United States

begun and held at the City of New-York, on

Wednesday the fourth of March, one thousand 

seven hundred and eighty nine.

THE Conventions of a number of the 

States, having at the time of their adopting the 

Constitution, expressed a desire, in order to 

prevent misconstruction or abuse of its powers, 

that further declaratory and restrictive clauses 

should be added: And as extending the ground 

of public confidence in the Government, will 

best ensure the beneficent ends of its institution.

RESOLVED by the Senate and House of 

Representatives of the United States of America, in Congress assembled, two thirds of both 

Houses concurring, that the following Articles 

be proposed to the Legislatures of the several 

States, as amendments to the Constitution of 

the United States, all, or any of which Articles, 

when ratified by three fourths of the said Legislatures, to be valid to all intents and purposes, as part of the said Constitution; viz.

ARTICLES in addition to, and Amendment of the Constitution of the United States of America, proposed by Congress, and ratified by the Legislatures of the several States, pursuant to the fifth Article of the original Constitution.

Article I—After the first enumeration required by the first article of the Constitution, there shall be one representative 

for every thirty thousand, until the number shall amount to one hundred, after which the proportion shall be so regulated 

by Congress, that there shall be not less than one hundred representatives, nor less than one representative for every forty 

thousand persons, until the number of representatives shall amount to two hundred; after which the proportion shall be so 

regulated by Congress, that there shall be not less than two hundred representatives, nor more than one representative for 

every fifty thousand persons. 

Article II—No law varying the compensation for the services of the Senators and Representatives, shall take effect, until 

an election of Representatives shall have intervened. 

Article III—Congress shall make no law respecting an establishment of religion, or prohibiting the free exercise thereof; 

or abridging the freedom of speech, or of the press; or the right of the people peaceably to assemble, and to petition the 

Government for a redress of grievances. 

Article IV—A well regulated Militia, being necessary to the security of a free State, the right of the people to keep and 

bear Arms, shall not be infringed. 

Article V—No Soldier shall, in time of peace be quartered in any house, without the consent of the Owner, nor in time 

of war, but in a manner to be prescribed by law. 

Article VI—The right of the people to be secure in their persons, houses, papers, and effects, against unreasonable 

searches and seizures, shall not be violated, and no Warrants shall issue, but upon probable cause, supported by Oath or affirmation, and particularly describing the place to be searched, and the persons or things to be seized. 

Article VII—No person shall be held to answer for a capital, or otherwise infamous crime, unless on a presentment or 

indictment of a Grand Jury, except in cases arising in the land or naval forces, or in the Militia, when in actual service in time 

of War or public danger; nor shall any person be subject for the same offence to be twice put in jeopardy of life or limb; nor 

shall be compelled in any criminal case to be a witness against himself, nor be deprived of life, liberty, or property, without 

due process of law; nor shall private property be taken for public use, without just compensation. 

Article VIII—In all criminal prosecutions, the accused shall enjoy the right to a speedy and public trial, by an impartial 
C H A P T E R 3 Individuals, Society, and Conservation 93

jury of the State and district wherein the crime shall have been committed, which district shall have been previously ascertained by law, and to be informed of the nature and cause of the accusation; to be confronted with the witnesses against him; 

to have compulsory process for obtaining witnesses in his favor, and to have the Assistance of Counsel for his defence. 

Article IX—In Suits at common law, where the value in controversy shall exceed twenty dollars, the right of trial by 

jury shall be preserved, and no fact tried by a jury, shall be otherwise re-examined in any Court of the United States, than 

according to the rules of the common law. 

Article X—Excessive bail shall not be required, nor excessive fines imposed, nor cruel and unusual punishments inflicted. 

Article XI—The enumeration in the Constitution, of certain rights, shall not be construed to deny or disparage others 

retained by the people. 

Article XII—The powers not delegated to the United States by the Constitution, nor prohibited by it to the States, are 

reserved to the States respectively, or to the people.
94 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 18—Moral Development (Wilber 1995): 

 Preconventional—egocentric, 

geocentric, biocentric, narcissistic, body bound

 Conventional—sociocentric, 

ethnocentric, culture-bound

 Postconventional—worldcentric, universal pluralism, asks 

“Who am I?” for the first time, 

reflexive and introspective, 

hypothetico-deductive, relies 

on evidence to settle issues

(continued from page 89)

Individual development—Jean Piaget reviewed the development 

of the individual mind and its parallels to the development of social 

systems. These parallels by age class include 0 to 2—sensorimotor 

(archaic, archaic-magic); 2 to 7—preoperational (egocentrism, perspectivism, realism, and reciprocity); 7 to 11—concrete operational 

thinking; and age 11+—formal operational thinking. 

The first imaginary images appear to the mind at 7 months. A 

child regards his or her own point of view as absolute and then discovers the possibilities of other points of view. Reality is that which 

is common to all points of view taken together. At 18 months, a 

child learns to differentiate his or her own feelings from the feelings of others. At 3 years, a child becomes a coherent and stable 

self, able to use language. Symbols are used, the first being the word 

“No!” Concepts are grasped, but magic still dominates the 2 to 4-

year-olds. Even at 4 to 7 years, children retain some belief that an 

individual can magically alter an object, but they recognize that their 

thoughts do not control the world. Thus, “magic,” says Wilber (1995), 

“is transferred to Daddy, God, or some volcano spirit.” Rituals and 

prayers are added to move from magic to magic-mythic. 

Carl Jung believed that all the forms and motifs of the world’s 

great mythologies are collectively inherited in the individual psyche 

of each of us—and Freud and Piaget agreed. Thus mythic membership produces an intensively cohesive social order. In the concrete 

operational stage, the child begins to enter the world of other minds 

and can take the role of others, but still is egocentric, sociocentric, 

and anthropocentric—centered on a role identity in a society of 

other roles. But the child can grasp the nature of a holon of whole/

parts, value hierarchies, and continua of preferences vs. the either-or. 

With formal operational thinking comes the transformation from 

role identity to ego identity, from sociocentric to worldcentric—

the capacity to distance oneself from egocentric and ethnocentric 

embeddedness and consider what would be fair to all people, not 

merely one’s own. Freedom from embeddedness in bodily impulses 

and assigned social roles produces the fully separated, individuated 

sense of self. Mythic membership gives way. A new world of feelings, dreams, passions, and idealism can develop. This is the first 

truly ecological mode of awareness—the child can grasp mutual interrelationships, take different perspectives, and coordinate systems. 

Formal operational thinking allows the child to understand justice, 

mercy, compassion, reciprocity, equality, conscience, rights, and responsibilities (sidenote 18). Emergence of rationality, however, can 

produce a massive loss of cultural meaning and social integration 
C H A P T E R 3 Individuals, Society, and Conservation 95

The transpersonal 

domain starts 

with reason, with 

truth established 

by evidence, and 

produces claims of 

higher awareness 

that embraces love, 

identity, reality, 

self, and truth.

and the need for new integration at the global level. 

Reason has its own inherent problems and limitations, but Wilber says that is no cause to “board the Regress Express and set the 

Way Back Machine to medieval or horticultural or foraging” or preEuropean settlement conditions. Rather, transpersonal development 

is called for—increasing interiorization and decreasing narcissism. 

One is no longer merely buffeted by immediate fluctuations in the 

environment and relative autonomy—the capacity to stay inwardly 

focused—increases individuation. This produces internalized action 

or the capacity to internally plan an action and anticipate its course 

rather than being merely an automaton. This vision-logic is the stage 

beyond formal operational thinking; it is dialectical, integrative, 

creative, synthetic, and integral a-perspectival. Formal operational 

thinking is simple problem solving; vision-logic produces creative 

scientists and thinkers. Ecology and relational awareness emerges 

with formal operational thinking but comes to fruition with vision-logic. Vision-logic integrates the well-differentiated matter, 

body, and mind. Vision-logic sounds good, but it is not the omega 

point of personal evolution; it has its downside, primarily dread, 

the existential malaise. The cure for this angst is transcendence. The 

transpersonal domain starts with reason, with truth established by 

evidence (results of experimental methods), and produces claims of 

higher awareness that embraces love, identity, reality, self, and truth 

(Wilber 1995).

Wilber (1995) says the single greatest task facing modernity and 

postmodernity is integrating the person, culture, and nature—integrating the interior subjective worlds of I and We with the exterior 

objective Ego (as worldcentric stance of universal pluralism, altruism, benevolence, and freedom) and the Eco (the biosphere). The 

whole point of rationality and its capacity for multiple perspectives 

is to put oneself in the shoes of others and find a mutual enrichment 

and appreciation of difference, a celebration of diversity. Another 

urgent task of postmodernity (the here and now) is the development 

and establishment of genuine environmental values—a moral and 

ethical stance toward nonhuman holons. One of the most obvious 

difficulties is the biocentrism of the eco-camp with all life forces 

having equal value and equal worth. Wilber (1995) offers a holarchic 

alternative: 

 All things and events are perfect manifestations of spirit, thus 

all holons have equal and ultimate value or equal ground-value.

 All holons are whole/parts, and thus have whole-value and intrinsic value (value in and of itself ). There are levels of significance, 
96 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

too—the greater the depth of holons, the more significant for 

the Kosmos; all have rights to exist, otherwise the whole dissolves.

 As parts, all holons have instrumental values (extrinsic value); 

the more “partness-value” (the greater the whole of which the 

holon is part), the more fundamental for the Kosmos.

In other words, it is much better to kill a carrot than a cow even 

though they are both perfect manifestations of the spirit with equal 

ground-value, but the cow has more depth (and consciousness).

Agencies, Organizations, and Society

It seems inescapable that public conservation agencies must evolve, 

develop, and become more democratic, informative, and facilitative 

to be of use in the 21st century (Danter et al. 2000). Impediments to 

organization change are various and formidable, internal and external (Bull 1994, French et al. 1994). Most conservation agencies are 

top-down, command-and-control, hierarchical bureaucracies with 

centralized techno-structures derived from the early industrial age 

and excessively inflexible. They are kept that way by internal power 

structures and external controls of laws, regulations, codified processes, and litigation and lobbying. Internal transformation is challenging enough—to change the policies and culture of a government 

agency is a complex endeavor. The former Lands Commissioner for 

the State of Washington offers the following advice (Belcher 2001): 

Be sure you want the job. Much of this book has been about the 

need for transformation and transcendence. Transformation does 

not occur without significant effort and without outside intervention. If we, as a society are to progress toward more effective, more 

democratic, more collaborative, more local forms of conservation, 

all the stakeholders—agencies, private and nonprofit organizations, 

and individuals—must undergo positive, purposeful change.

What is our purpose? What are we about? There seems to be an 

emerging consensus for conservation; common themes are arising 

across the globe. For most of us, attachment to family, community, 

and place helps define us. We wish to form a civil society that strives 

for attainment of human happiness and achievement of human 

potential, provides for social justice and equity for the present and 

future generations, and preserves the capacity of the all-important 

land that is our home, sustenance, and future opportunity.

We cannot leave it to others to preserve our land, our 
C H A P T E R 3 Individuals, Society, and Conservation 97

Regine Carey leans against a giant 

yellow cedar. Photo by A. Carey.

communities, or our sense of well-being. We must do it ourselves, 

from the bottom up. Our society suffers from the yoke of the topdown. We must “think globally and act locally.”

Those who are attached to place emotionally, culturally, economically, and spiritually, must be the ones to discover the path to 

harmony in the shared ownership of the land. We must learn together and jointly make decisions about how to conserve the land 

and nature.

Science, Scientists, and Society 

In the postmodern world, science and scientists have come under 

increasing criticism because of their ways of thinking and of participating in the greater society. Maser (1994) listed five roadblocks 

to legitimate scientific acquisition of new knowledge: lure of grants 
98 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

(and legislatively appropriated research funds) aimed at predetermined results; attachment to a single hypothesis; scientific methodology that can only reject or fail to reject hypotheses (no formal 

mechanism for proof ); science used to safeguard established dogma; 

science in denial of human participation in nature. It is obvious that 

the processes of distributing funds for conservation science (from 

legislatures through funding agencies and organizations) are driven 

by a combination of external forces of present and emerging crises 

and public demand and the political philosophies, prevailing science dogma, and environmental philosophies of those involved in 

the distribution processes. Funding for conservation science does 

not necessarily follow any rational, critical examination of gaps in 

knowledge, and this should be made clear to users of science. Other 

ways in which scientists and other people involved in conservation think and behave also may squelch development of consensus 

(­Maser et al. 1998):

 Scientists without a spiritual foundation, in a sea of arrogance 

and increasing intellectual isolation.

 Continuing narrow specialization that produces fragmented 

worldviews.

 People pointing outside of themselves to the causes of environmental problems.

 Asking science to answer questions about social ideas.

 Ostracizing those with the courage to question the acceptance 

of normal scientific inquiry.

The scientific community acknowledges many of these, and other, concerns; e.g., focus on contemporary research erases historical 

contributions of science and leads to science recycling (Graham and 

Dayton 2002). Still, successful collaborative management requires 

a base of science information (Wondolleck and Yaffee 2000). Collaborative management must deal with complexity, uncertainty, and 

change; it must integrate across space and time. Collaborative management must build understanding among stakeholders, coordinate 

across boundaries, make effective decisions, and develop the capacity to deal with future challenges. It cannot do any of these without 

good science and technical support. People making decisions about 

conservation often need quantitative, or at least qualitative, estimates 

of ecological values. Placing values on the environment depends on 

the skill and is influenced by the culture of the researcher (Pizzolotto 1994). Value concepts can be influenced by both scientific and 

social factors, which may be in conflict. Criteria such as naturalness 
C H A P T E R 3 Individuals, Society, and Conservation 99

Sidenote 19—Common 

beliefs that underlie feelings 

about public forest management 

activities in Michigan with relative importance to influencing 

management indicated by percent 

value (adjusted r2) (Carr and 

Halvorsen 2001): 

Community/forest linkages:

 Forests are as much a part of 

a community as streets and 

buildings: 8 percent

 Forest lands are a community 

to which humans belong: 6 

percent

Forests as ecological systems:

 Forests should be managed 

like an agricultural crop: 26 

percent

 Managing forests for any purpose upsets nature’s balance: 

25 percent

 Forests are such complex 

ecosystems they cannot be 

managed at all: 18 percent

Making management decisions:

 Citizens working together can 

make the best decisions about 

how to manage public forests: 

9 percent

 How forests are managed is 

the responsibility of the professional forester: 6 percent

Values that should be protected:

 Forests should be managed to 

protect their ecological value: 

21 percent

 Forests should be managed to 

protect their recreation value: 

17 percent

 Forests should be managed to 

protect their economic value: 

17 percent

 Forests should be managed to 

protect their spiritual value: 15 

percent

 Forests should be managed to 

protect their commodity value: 

13 percent

and rarity are almost never referenced to an objective zero value. In 

most cases, evaluation is done by criteria that distinguish between 

natural (undisturbed) and highly degraded conditions. Natural is 

relative (everything is natural) and the idea that man takes part in 

this naturalness seems largely accepted, especially in Europe with a 

long history of a natural-cultural mosaic (see fig. 2C).

Social Sciences

Christensen and Donoghue (2001) suggested a research framework 

for conservation in the Pacific Northwest that recognized that (1) 

social values are unknown for rural people, communities, and development; (2) traditional concepts of rurality do not reflect today’s 

rural places and people; (3) collaborative management—collaborative stewardship for ecosystem management—is largely undeveloped; and (4) socioeconomic change in rural communities is poorly 

understood. They quote Gifford Pinchot, the founder of the U.S. 

Forest Service: “It is the duty of the Forest Service to see to it that 

... every ... resource of the forest is used for the benefit of the people 

... in the neighborhood ... .” 

Research on social aspects of conservation has been growing 

and gaining focus as communities demand more active, meaningful 

roles in conservation planning (Kruger 2003). Studies of community-forest relations now use a variety of approaches—conventional 

objective methods, collaborative inquiry, and rapid rural appraisals 

by using open-ended surveys and focus groups. All the methods are 

subject to criticism, but what is most lacking is clear definition of 

purpose—for whose interest, to what end (Sturtevant 2003)? Dialogue, active listening, and triangulation using different sources of 

data and methods allow analyses that can contradict, complement, 

and confirm existing knowledge of the community; what is more 

difficult to address is that some communities lack even the social 

and human capital to participate; inequality, disaffection, and quiescence may impede participation (see also Carr and Halvorsen 2001) 

(sidenote 19). Citizen juries offer unique and novel opportunities to 

engage the public in conservation values (Ward 1999). A small, but 

socially representative group is provided with time and information 

to conduct a democratic deliberation about what it is worth to pursue conservation when there is no market value to establish prices. 

These participants (or their employers) can be financially compensated for the large investment of time required. Some advantages 

relative to other methods of inquiry are that the participants can 
100 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

engage in collaborative learning and become well informed; the 

deliberative process can become more democratic and legitimate; 

social dimensions are more likely to be captured; and distributional 

issues are likely to be addressed more directly. Potential problems 

include poor representativeness, bandwaggoning, stentorian opinion leadership, tight definition of the agenda by sponsors, providing 

partial or selected information, and juror preconceptions. 

Studies of populations restructuring following immigration 

and the implications for conservation, economics, and the cultural 

dimensions of social life are emerging (Nelson 2002, Overdevest 

2000). Participatory action research includes a variety of methods 

but emphasizes education and developing of consciousness in communities through the Aristotelian principle that individual fulfillment can be achieved through participation in improving the quality of life by working with others for the common good (Kruger 

and Sturtevant 2003). This democratic participation allows people 

to discuss, formulate, and decide public issues that are important to 

them and that directly affect their lives. In this research, managers, 

scientists, and planners take on new roles as facilitators and teachers, 

guiding public deliberation from below. Participatory action research 

accommodates the present paradigm shift away from the public 

land management leviathan born of centralization, specialization, 

rationalism, depersonalization, and industrialism.

Conservation research seems to lack (1) participant-observer 

anthropological methods, (2) intervention methods in which scientists embed themselves in social processes, and (3) values elicitation 

based on specific communities and specific places. However, such 

research is emerging. Presented here is a summary of an anthropological investigation, followed by some intervention methods, and 

finally, some ideas about values elicitation.

Terre Satterfield (2002) provided a fascinating analysis of identity, knowledge, and emotion in the conflict between loggers and 

environmentalists over old-growth forests in Oregon. She reported 

that few environmental controversies have been more dramatic than 

that contest of political, economic, and scientific forces. Congressman DeFazio of Oregon described it as a “religious war.” In the contests of culture and power, culture consists of shared webs of meaning, moral outlooks, and worldviews internalized in the behavior of 

the members of each culture versus the overarching, multiorigined, 

and multifaceted cultural resource that individuals draw upon while 

manipulating it to fit their own ends. Both loggers and environmentalists talk about the joy of being close to nature, about forest science, 

about being victims of greater economic and political forces, about 
C H A P T E R 3 Individuals, Society, and Conservation 101

Sidenote 20—Albert Einstein once said, “Common sense 

is both the refinement of everyday 

thinking and the collection of 

prejudices acquired by the age of 

eighteen” (Satterfield 2002).

the implications of the past for the future landscape, and about being emotional activists. In shaping its vision of a new and better 

world, each group manipulates its references to reflect features of 

the overall social system perceived to be dominant (a process known 

as fugitive political conduct of subordinate groups). This is a creative 

means by which people reconfigure cultural systems. Oppositional 

dialogues are basic to identify cultural conflicts. Activists concerned 

with altering the status quo state their grievances and their imagined 

new and better worlds. They make repeated public statements about 

who they are and how different they are from their opponents. And 

they mobilize by staking out identity centered on territory and by 

invocations to common cause. Satterfield concluded that all battles 

about the physical environment are battles about place and the ties 

between place and identity. Both environmentalists and loggers 

make up communities attached to places, even though mobility and 

mass communication mean very few communities are integrated, 

geographically bounded wholes. Rather communities are made up 

of people in separate places (environmentalists in cities, loggers in 

rural settings) effectively becoming a single community through the 

continuous circulation of people, money, goods, and information.

The social identities of loggers and environmentalists were well 

established. Loggers were natural-resource workers, informed by 

applied science based on common sense empiricism, and reflecting 

the conservation ethic of the first Chief of the U.S. Forest Service, 

Gifford Pinchot (forests are fertile, renewable crops are in need of 

protection). The central concern of the loggers was the long-term 

sustainability of communities based on family-wage employment, a 

spirited logging ethos, and the forests. Environmentalists saw themselves as an ecological resistance movement deeply concerned with 

spirituality, aesthetics, and biocomplexity, willing to commit their 

minds and bodies to protecting old growth, and reflecting the land 

ethic of John Muir and Aldo Leopold. The two groups did not conform to traditional sociopolitical divisions based on class, gender, or 

political party. Both groups were sensitive to the privilege granted 

scientific explanations in policy formulations. But neither trusted 

science; both used it selectively to bolster their arguments. 

Loggers were attracted to science that makes common sense 

(sidenote 20) and knowledge gained through practice. Given the 

collapse of modern science and its contention that forestry should 

be a rationalized agricultural process, loggers were left to develop 

their own identity-based critique of expert knowledge, especially 

when expert opinion violated common sense. Environmentalists 

preferred science that acknowledged the mystery and sanctity of the 
102 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

natural world. Environmentalists were especially ambivalent about 

science because of their uncertainty about exactly where to place an 

eco-centered self in the field of authoritative knowledge. Satterfield 

states that an abstract, deeply ambivalent, and anti-applied image of 

science is entirely consistent with a belief in the need for humans 

to maintain a humble, unintrusive stance toward nature. Thus, both 

groups sought to rewrite the criteria for valid knowledge. 

Satterfield goes on to recount the history of the exploitation 

of natural resources in the Pacific Northwest and feelings of betrayal both groups experienced at the hands of federal managers, 

stating, “The destruction of communities and the depletion of resources have distinguished the political economy of Washington, 

Oregon, and northern California.” In describing the contrast of the 

environmentalist nostalgia and glorification of past epochs with the 

loggers’ idea of rural living embedded in an ecologically benign lifestyle (with a historical claim to place), Satterfield asks “Under what 

temporal, social, and even spiritual arrangement do claims of place 

attachment become legitimate?” Satterfield’s anthropological participant-observer research provides considerable understanding to 

policymakers and stakeholders in conservation debates. Her book 

certainly provides a basis for mutual understanding and a resource 

for achieving some common vision. She concludes that the conflict 

will not be solved, and improved logging practices will not be created if the more imaginative and experientially wise activists on both 

sides are silenced. In determining values of stakeholders, moral concerns, situational uniqueness, and context specificity of imaginings 

makes elicitation of values by discussions and surveys problematic. 

There are two key considerations: (1) Language, power, and creative 

thought are not captured by value-elicitation processes dominated 

by economic approaches such as cost:benefit analyses that assume 

the majority of the public endorses rational, economic expression of 

the market values of nature and that monetary expressions of value 

reflect that which is held dear, worthy of protection, and ethically or 

socially esteemed. Economic approaches privilege some actors and 

marginalize others. (2) Stakeholder values are not neat and discrete, 

but contextual. These conclusions lead one to conclude that data 

collection and analysis by centralized staffs for use by line officers 

in decisionmaking are likely to be poorly informative; direct participation by stakeholders in deliberations about specific policies and 

practices in specific contexts and places are more likely to capture 

the desires of the stakeholders.

Place is a powerful social influence on conservation politics, and 

place-based inquiry brings to the fore the diverse ways in which 
C H A P T E R 3 Individuals, Society, and Conservation 103

Sidenote 21—The world’s 

most important problems, according to Ehrenfeld (2002): 

 Materialism

 Deterioration of communities

 Anomie

 Commercialization of formally 

communal functions (health, 

charity, communication)

 The growth imperative

 Exploitation of the Third 

World

 Disintegration of agriculture

 Ignorance of the ecology of 

diseases, especially epidemic 

disease

 Loss of important skills and 

knowledge

 Devastating decline in the 

moral and cultural-intellectual 

education of children

 Impoverishment and devaluation of language

 A turn from environmental 

and human realities to electronic substitutes

A narrow disjunct 

focus reflecting 

disciplinary myopia 

is not serving us 

well.

values and meanings are articulated and negotiated, but which are 

typically excluded in conservation decisionmaking (Cheng et al. 

2003).

Forest ecology—Perry (1998) identified the major scientific challenges for conservation as understanding (1) the relationship between managed forest structure and ecological function at the stand 

scale; (2) spatial patterning of stand-level structures that meet biodiversity goals for a given bioregion; and (3) temporal dynamics of 

stand and landscape structures resulting from natural disturbance, 

anthropogenic disturbance, and their interactions. He reviewed the 

major strategies of ecosystem management and their failings and 

concluded that (1) reserves cannot be large enough to preserve regional biodiversity; we also need managed forest to function to conserve biodiversity; (2) it is a false belief that logging of any kind 

fits within the range of natural variation; the question is, how far 

can management depart from natural disturbances before compromising system integrity?; (3) complexity and stability are linked but 

poorly understood; we need a better understanding of structure, 

process, and function at local and landscape scales. Conservation 

research has been focusing on fragments of narrow problems, never 

mind the major problems facing humanity (sidenote 21). A narrow 

disjunct focus reflecting disciplinary myopia is not serving us well 

(Ehrenfeld 2002, Stevens and Montgomery 2002).

Collaborative management—Improved problem solving and leadership are needed to address conservation problems. Interdisciplinary problem solving incorporating problem definition in human-social terms, mapping the social (sidenote 22) and decision processes, 

analyzing basic beliefs, and clarifying one’s own worldview are 

necessary (Clark 2001) (sidenote 23). But, take these truths to be 

self-evident (Wondolleck and Yaffee 2000): (1) agencies tend to be 

biased and ineffective, (2) traditional decisionmaking has been biased and ineffective, and (3) people are frustrated by the adversarial 

decisionmaking process. Even with massive investments of time, 

money, and interdisciplinary science, conservation decisionmaking 

by federal agencies in the Pacific Northwest produced ongoing controversy (Associated Press 2003, Barnard 2003, Dodge 2002, Dombeck and Thomas 2003, McCool and Kruger 2003, Milstein 2002). 

Conservation scientists (Anderson et al. 1999) have recommended 

left-brain approaches (a priori agreement on analyses, rules, structure, and order) that are more likely to be perceived as the power 

politics of science rather than attempts at consensus building. In 
104 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 22—The social 

process includes (Clark 2001):

Participants:

 Who is participating? 

 Who is demanding to participate?

 Who else should be participating?

Perspectives:

 Demands—What do the 

stakeholders want?

 Expectations—What are the 

stakeholder assumptions about 

the future?

 Identifications—On whose 

behalf are decisions being 

made and what are their perspectives?

Situations:

 In what situations do stakeholders interact?

 Where should they interact?

Base values:

 What are the assets and resources of the stakeholders?

Strategies:

 Which ones are being used or 

are available for use?

Outcomes:

 What are they?

 Who is benefiting?

 Who is being deprived?

 What should the distribution 

of values be?

actuality, these recommendations are a response to perceived bad 

faith on the part of some participants in collaborative data analysis. 

Collaborative learning requires open communication, diverse participation, unrestrained thinking, constructive conflict, democratic 

structure, multiple sources of knowledge, extended engagement, and 

facilitation (Schusler et al. 2003). The questions of who is at the 

table, who they represent, why ethical behavior is presumed, and 

what happens if consensus cannot be reached need to be emphasized (Overdevest 2000). Setting ground rules for process, interactions, behaviors, facilitation, attendance, and many other issues is 

essential. But true collaboration is needed. 

Collaboration is the pooling of resources by two or more stakeholders to solve problems (Wondolleck and Yaffee 2000) (sidenote 

24). But the key to conservation is to have all stakeholders fully 

represented in the collaboration and to proceed on the local level. 

Success in collaboration is defined in the perceptions of the participants, although objective and standardized measures of progress are 

desirable (Rolle 2002) (sidenote 25). As collaborative management 

matures, increasing emphasis should be put on continuous process 

improvement and the application of the principles of total quality 

management and adaptive management. Similarly, considerable experience has been gained with self-directed work teams in industry 

that can be applied to collaborative management groups (Harper 

and Harper 1993, Katzenbach and Smith 1993). These sophisticated approaches are becoming increasingly feasible as various stakeholders are becoming more sophisticated and often represented by 

well-trained and highly educated professionals employed or volunteering in nongovernmental organizations. As the complexity of 

conservation problems increases, so does the need for collaborative 

management, and the need for adequate funding of collaborative 

management. Conservation decisions have profound, sometimes irreversible effects, on local communities (McCool and Kruger 2003). 

Investment in collaborative learning and collaborative management 

is becoming increasingly common in the public, nonprofit, and industrial sectors. There seems to be no viable alternative; top-down, 

command-and-control approaches are inflexible and ineffective 

(Wondolleck and Yaffee 2000).

Collaborative management has a long history in the Pacific 

Northwest—over 230 successful public-private cooperatives have 

been established (Wondolleck and Yaffee 2000). The fifth national 

park to be designated was Mount Rainier National Park in 1899; 

its designation, unlike previous parks, arose from a people’s campaign, well organized, sustained, and based in large part on a “love 
C H A P T E R 3 Individuals, Society, and Conservation 105

Sidenote 24—Resources, 

values, or bases of power can be 

quite diverse (Clark 2001), e.g. 

people can give and receive:

 Power: support in making 

decisions in specific contexts

 Enlightenment: information

 Wealth: opportunity to control resources including money, 

people, and parcels of nature

 Well-being: opportunity for 

personal safety, health, and 

comfort

 Skill: opportunity to develop 

talents into operations of all 

kinds including professional, 

practical, and artistic skills

 Affection: friendship, loyalty, 

love, and intimacy in interpersonal situations

 Respect: recognition in a 

profession or community

 Rectitude: appraisal about responsible and ethical conduct

Sidenote 23—Clark (2001) 

cites Lasswell’s five tasks of problem orientation:

 Clarify goals or preferred 

outcomes.

 Describe trends including 

changes relevant to goals.

 Analyze factors that shape 

trends, including causes, motives, and policies.

 Make projections about likely 

future developments under 

various circumstances.

 Invent, evaluate, and select 

alternatives to pursue goals.

of landscape” and Mount Rainier, “the mountain that was god,” as a 

symbol of place (Catton 1996). Collaborative management evolved 

in response to problems caused by agency policy and land management, business practices, and impasses in conservation owing to 

conflicts that persist through administrative, legislative, and judicial 

processes. The consequences of the current dysfunctional modes of 

decisionmaking have been public alienation and pervasive mistrust. 

Six of ten Americans feel powerless and disenchanted; less than half 

express confidence in U.S. institutions. The roots of collaborative 

management are in the neighborhood and community and are not 

purely interest driven and are always, to some degree, place driven. 

A famous Pacific Northwest collaborative management group, the 

Quincy Library Group, has a strong sense of place; a local focus; 

shared problems, fears, and sense of crisis; shared goals and interests; a common vision statement; and compatible interests. Another 

famous Pacific Northwest group, the Applegate Partnership, has a 

similar character. An emerging overarching conservation objective, 

for which there seems to be an evolving consensus, is sustainability. 

Conservation collaborative management recognizes the need to integrate different geographic and temporal scales and the need to 

deal with complexity, uncertainty, and change. Collaborative management not only acknowledges, but also makes sense of the three 

principal human communities (place, identity, and interest) and decentralizes decisionmaking, producing a civic environmentalism. 

The benefits of collaborative management include effective decisionmaking; improved understanding among agencies, organizations, and the public; cross-boundary coordination; and improved 

capacity to deal with future challenges (Michaels et al. 2001, Wondolleck and Yaffee 2000, Yaffee and Wondolleck 2000) (sidenote 

26). Collaborative management requires processes that include early, 

frequent, and ongoing involvement; substantive involvement; consensus decisionmaking; inclusive and representative makeup; cooperative, not adversarial attitudes; and flexible, positive attitudes. Collaborative management requires collaborative learning—joint fact 

finding, inventing options collaboratively, and developing a common 

understanding with a base of scientific information and information 

from independent, outside experts and scientists (Wondolleck and 

Yaffee 2000).

Of course, collaborative management is not a panacea; concerns 

about collaborative management include accountability, adherence 

to law, the demands placed on public and private groups, cooption 

by local economic development interests, and problems in evaluation 

(Conley and Moote 2003, Overdevest 2000). Increasing emphasis is 
106 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 26—Successful 

collaborative efforts (Wondolleck 

and Yaffee 2000):

 Build on a sense of community/shared vision

 Create new opportunities for 

interaction among diverse 

groups

 Generate effective and enduring processes

 Develop more open, flexible, 

and holistic mind sets

 Establish responsibility, ownership, and commitment

 Create proactive and entrepreneurial behavior

 Build support and resources 

from numerous sources

Sidenote 25—Rolle (2002) 

suggested that the progress of a 

collaborative group can be evaluated by its ability to (1) meet its 

mission and achieve outcomes; (2) 

be sustained; (3) understand the 

community; (4) be inclusive and 

diverse, reflect the community; (5) 

create a forum for diverse ideas 

and shared learning; (6) increase 

community capacity; (7) increase 

cooperation across organizational, 

administrative, and jurisdictional 

boundaries; (8) stimulate innovation, new ways of doing business; and (9) facilitate changes in 

policy, laws, and programs.

being placed on evaluating the efficacy and efficiency of conservation efforts worldwide (Bare et al. 2000, Christensen 2003). Collaborative management “takes a lot of care and feeding” (Wondolleck 

and Yaffee 2000). The basic dilemma is cooperation versus competition. That competition is more rational than cooperation from the 

point of the individual, and the collective will not do as well under 

competition as with cooperation, have been recognized since the 

time of Aristotle. Economics, evolutionary biology, and political science all presume individuals maximize self-interest and undermine 

cooperation. The prime example is Garrett Hardin’s tragedy of the 

commons. Institutional barriers are numerous as are barriers owing to attitudes and perception. Singleton (2002) evaluated three 

cases of collaborative watershed planning in the Pacific Northwest. 

Success was impressive in some areas, but limited by difficulty in 

resolving core conflicts over equity, distributive effects of conservation planning, competing visions of nature, and goal. But, Singleton 

states, collaborative environmental policymaking is clearly an idea 

whose time has come. The rationale for devolution of decisionmaking power is that local people and local governments have clearer 

understandings of local socioeconomic and cultural circumstances 

and are better equipped to devise fine-tuned regulatory solutions 

to environmental problems than those who make top-down centralized decisions. What is needed is local autonomy coupled with 

broad accountability. The promise of collaborative management is 

satisfying local needs while conforming to state and federal law.
C H A P T E R 4

Conservation Revisited

Conservation is the set of attitudes, principles, and practices we 

adopt individually and collectively to meet people’s needs and fulfill 

people’s aspirations from nature while not diminishing the capacity of nature for renewal, for creativity and evolution, to meet the 

needs of future generations, and to support a present and future diversity of life on Earth. Biologically, diversity is defined in terms of 

genes, populations, species, and other taxa and levels of organization 

such as biotic communities and ecosystems. Biodiversity, however, 

is more than the variety of things in a defined set. Biodiversity is a 

concept with philosophical, social, economic, and political components because the diversity of life is an irreplaceable asset to humanity and the biosphere. Biodiversity is a blanket term for the natural 

biological wealth that is the foundation for human well-being. Nature seems a better term. The challenge of nature conservation is 

integrating diverse worldviews and philosophies to achieve general 

sustainability of human communities. Conservation of biodiversity 

(nature) is “... management of human interactions with the variety 

of life forms and ecosystems so as to maximize the benefits they 

provide today and maintain their potential to meet future generations’ needs and aspirations” (Reid and Miller 1989).

Biodiversity is inseparable from the ecological, evolutionary, 
108 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

and managerial processes of nature that affect biological diversity. 

These processes include climate change, weather patterns, hydrologic cycles, pollution, photosynthesis, soil generation, nutrient cycling, 

and maintenance of soil fertility, water cycling, predation, mutualism, competition, parasitism, pest control, silviculture, grazing management, agriculture, animal husbandry, and horticulture. Linkages 

among processes must be taken into account whether the goal is to 

obtain products from individual species, services from ecosystems, 

or to keep ecosystems in a natural state for future generations. Altering ecosystems affects both processes and biodiversity, but with a 

wide range of ecosystem- and alteration-specific outcomes. Nevertheless, there are guiding principles (Reid and Miller 1989):

 The mix of species making up a community changes constantly 

even under conditions of environmental stability; thus, conservation of biodiversity should not be aimed at maintaining exact 

community composition, but at maintaining the overall variety 

of species while allowing ecosystems to change. 

 Biodiversity increases with environmental heterogeneity at multiple scales. 

 Spatial heterogeneity influences not only the composition of 

species within a community but also the interactions among 

species, including competition, parasitism, and predation.

 Periodic disturbances are important in creating mosaics that 

foster high species diversity. 

 Size and isolation can influence community composition, as can 

the transition zones between communities. 

 Certain species have disproportionate influences on ecosystems; 

some species are prone to extirpation.

Thus, understanding how complex systems emerge from the 

interaction of biological entities at all levels with the external environment is critical to understanding ecosystem function; a systems 

approach is necessary. Biocomplexity, not just biological diversity, is 

the defining property of ecosystems (Dybas 2001). 

Given that current extinction rates are high and accelerating 

and that human populations are growing, using more resources, and 

generating more wastes, Pimm et al. (2001) asked, “Can we defy 

Nature’s end?” They answered themselves: the first priority is protecting remaining natural ecosystems. They concluded that saving 

the remaining diversity is possible. Globally, the greatest harm is 

impacts on vulnerable diverse areas that contribute relatively little 

to human economic well-being, such as humid tropical forests that 
C H A P T E R 4 Conservation Revisited 109

Sidenote 27—Kareiva and 

Marvier (2003) asked what about 

coldspots (i.e., the Arctic or 

Serengeti)? The hotspot approach 

has five significant flaws: 

 Hotspots for different taxa 

do not necessarily coincide, 

hotspots are often identified by 

plants lists that are not necessarily indicative of other taxa, 

and most taxa are unstudied.

 Degree of threat (present and 

future) is hard to quantify.

 The hotspot approach is 

reasonable only if the only goal 

is to protect the largest possible number of species in the 

smallest possible area.

 Focus on hotspots could allow 

major ecosystems to degrade.

 Hotspot conservation ignores 

environmental sustainability.

contain two-thirds of all terrestrial species and the Amazon, Congo, 

and Southeast Asia rivers that contain one-half the freshwater fish 

species. They also concluded that protecting diversity is economically feasible. But there is no single answer to protecting diversity. The 

Pimm approach protects biodiversity for its intrinsic values. Protected areas and reserves are not sufficient for either simple species 

conservation or to maintain the capacity of nature to provide future 

generations of people, other animals, plants, and fungi with the same 

opportunities for quality of life and evolution today’s species have. 

The most pressing need today is to train and empower conservation 

professionals to meet with interested citizens, help them assemble 

into collaborative learning communities, and to inform and facilitate a process of collaborative management (see also Pinchot Institute for Conservation 2001). Conservation organizations need to 

modernize and begin using 21st-century methods of organizational 

and professional management and development (French et al. 1994, 

Katzenbach and Smith 1993, Rummler and Brache 1995, Senge 

1990). Agencies need financial and political support to develop their 

human capacities. Conservation research and management should 

be distributed away from centralized authorities and organizations, 

close to the front lines of on-the-ground management. Certainly, 

immediate protection of biodiversity is needed in the Third World; 

hotspots and coldspots of diversity should be identified (Kareiva and 

Marvier 2003) (sidenote 27). Preservation of hotspots, regions with 

unusually high concentrations of endemics that have also suffered 

severe habitat destruction, such as tropical rain forest, oceanic islands, Mediterranean ecosystems in California and South Africa, 

is the reigning conservation paradigm. Other approaches can be 

taken in the First World, from reducing consumption and waste to 

managing the environment intentionally at multiple scales; from local community management of forests to governmental regionwide 

management and regulation of solid waste, air quality, water quality 

and supply, transportation networks, and energy supplies. There is 

a broad consensus that more research is needed on links between 

biodiversity, ecosystems, ecological services, and people. But there is 

a crying need for action research (French et al. 1994) that can enable 

people to come together to solve local problems.

Five years after the Rio conference in 1992 (callout 4), 1.3 billion 

people lived in absolute poverty, 20 percent of the world population lacked access to safe water, and 840 million people suffered 

malnutrition. Globalization of economies accelerated and led to accelerated environmental degradation. Citizens in the United States 

consumed in 1 year what citizens of Africa or India consume in their 
110 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

lifetimes. Problems of poverty, population growth, industrial and social development, depletion of natural resources, and destruction of 

the environment are closely interrelated and call for political transformation to sustainable development (Brown 2000). A substantial 

minority in the United States is concerned with intergenerational 

equity; but we need to make that a majority that is also concerned 

with intragenerational equity. We cannot pursue conservation without compassion, conscience, and consciousness.

In our ongoing cultural evolution, paradigms shift and, sometimes, new ones emerge. An emerging paradigm is the reflective, 

living systems paradigm (Elgin and LeDrew 1997). This paradigm 

includes a growing capacity for self-reflection and an ability to make 

fresh choices. It has a living system view of wholeness and interconnectedness. Its goal in life is to develop a balanced relationship between inner and outer selves and live in a way that is sustainable and 

compassionate, with conscious consumption. Conscious consumption is an ever-changing balance of inner and outer, material and 

spiritual, personal and social. Sense of self grows through conscious, 

loving, and creative participation in life. It is natural to respect all 

that exists as integral to the larger body of life. This paradigm bodes 

well for humanity. Older paradigms do not (Regier 1993).
Callout 4—Rio Declaration on Environment and Development (United Nations 1972)

The United Nations Conference on Environment and Development, having met at Rio de Janeiro from 3 to 14 June 1992, 

reaffirming the Declaration of the United Nations Conference on the Human Environment, adopted at Stockholm on 

16 June 1972, and seeking to build upon it with the goal of establishing a new and equitable global partnership through 

the creation of new levels of cooperation among states, key sectors of societies and people, working towards international 

agreements which respect the interests of all and protect the integrity of the global environmental and developmental 

system, recognizing the integral and interdependent nature of the Earth, our home, proclaims that

 Principle 1—Human beings are at the center of concerns for sustainable development. They are entitled to a healthy 

and productive life in harmony with nature.

 Principle 2—States have, in accordance with the Charter of the United Nations and the principles of international 

law, the sovereign right to exploit their own resources pursuant to their own environmental and developmental policies, and 

the responsibility to ensure that activities within their jurisdiction or control do not cause damage to the environment of 

other States or of areas beyond the limits of national jurisdiction.

 Principle 3—The right to development must be fulfilled so as to equitably meet developmental and environmental 

needs of present and future generations.

 Principle 4—In order to achieve sustainable development, environmental protection shall constitute an integral part 

of the development process and cannot be considered in isolation from it. 

 Principle 5—All States and all people shall cooperate in the essential task of eradicating poverty as an indispensable 

requirement for sustainable development, in order to decrease the disparities in standards of living and better meet the 

needs of the majority of the people of the world. 

 Principle 6—The special situation and needs of developing countries, particularly the least developed and those most 

environmentally vulnerable, shall be given special priority. International actions in the field of environment and development should also address the interests and needs of all countries.

 Principle 7—States shall cooperate in a spirit of global partnership to conserve, protect and restore the health and 

integrity of the Earth’s ecosystem. In view of the different contributions to global environmental degradation, States have 

common but differentiated responsibilities. The developed countries acknowledge the responsibility that they bear in the 

international pursuit to sustainable development in view of the pressures their societies place on the global environment 

and of the technologies and financial resources they command.

 Principle 8—To achieve sustainable development and a higher quality of life for all people, States should reduce and 

eliminate unsustainable patterns of production and consumption and promote appropriate demographic policies.

 Principle 9—States should cooperate to strengthen endogenous capacity-building for sustainable development by 

improving scientific understanding through exchanges of scientific and technological knowledge, and by enhancing the 

development, adaptation, diffusion and transfer of technologies, including new and innovative technologies.

 Principle 10—Environmental issues are best handled with participation of all concerned citizens, at the relevant level. 

At the national level, each individual shall have appropriate access to information concerning the environment that is held 

by public authorities, including information on hazardous materials and activities in their communities, and the opportunity to participate in decisionmaking processes. States shall facilitate and encourage public awareness and participation 

by making information widely available. Effective access to judicial and administrative proceedings, including redress and 

remedy, shall be provided.

 Principle 11—States shall enact effective environmental legislation. Environmental standards, management objectives 

and priorities should reflect the environmental and development context to which they apply. Standards applied by some 

countries may be inappropriate and of unwarranted economic and social cost to other countries, in particular developing 

countries.

 Principle 12—States should cooperate to promote a supportive and open international economic system that would 

lead to economic growth and sustainable development in all countries, to better address the problems of environmental 

degradation. Trade policy measures for environmental purposes should not constitute a means of arbitrary or unjustifiable 

discrimination or a disguised restriction on international trade. Unilateral actions to deal with environmental challenges 

outside the jurisdiction of the importing country should be avoided. Environmental measures addressing transboundary or 

global environmental problems should, as far as possible, be based on an international consensus.

C H A P T E R 4 Conservation Revisited 111
 Principle 13—States shall develop national law regarding liability and compensation for the victims of pollution and 

other environmental damage. States shall also cooperate in an expeditious and more determined manner to develop further 

international law regarding liability and compensation for adverse effects of environmental damage caused by activities 

within their jurisdiction or control to areas beyond their jurisdiction.

 Principle 14—States should effectively cooperate to discourage or prevent the relocation and transfer to other States 

of any activities and substances that cause severe environmental degradation or are found to be harmful to human health.

 Principle 15—In order to protect the environment, the precautionary approach shall be widely applied by States according to their capabilities. Where there are threats of serious or irreversible damage, lack of full scientific certainty shall 

not be used as a reason for postponing cost-effective measures to prevent environmental degradation.

 Principle 16—National authorities should endeavour to promote the internalization of environmental costs and the 

use of economic instruments, taking into account the approach that the polluter should, in principle, bear the cost of pollution, with due regard to the public interest and without distorting international trade and investment.

 Principle 17—Environmental impact assessment, as a national instrument, shall be undertaken for proposed activities 

that are likely to have a significant adverse impact on the environment and are subject to a decision of a competent national 

authority.

 Principle 18—States shall immediately notify other States of any natural disasters or other emergencies that are likely 

to produce sudden harmful effects on the environment of those States. Every effort shall be made by the international 

community to help States so afflicted.

 Principle 19—States shall provide prior and timely notification and relevant information to potentially affected States 

on activities that may have a significant adverse transboundary environmental effect and shall consult with those States at 

an early stage and in good faith.

 Principle 20—Women have a vital role in environmental management and development. Their full participation is 

therefore essential to achieve sustainable development.

 Principle 21—The creativity, ideals and courage of the youth of the world should be mobilized to forge a global partnership in order to achieve sustainable development and ensure a better future for all.

 Principle 22—Indigenous people and their communities and other local communities have a vital role in environmental management and development because of their knowledge and traditional practices. States should recognize and 

duly support their identity, culture, and interests and enable their effective participation in the achievement of sustainable 

development.

 Principle 23—The environment and natural resources of people under oppression, domination, and occupation shall 

be protected.

 Principle 24—Warfare is inherently destructive of sustainable development. States shall therefore respect international law providing protection for the environment in times of armed conflict and cooperate in its further development, as 

necessary.

 Principle 25—Peace, development and environmental protection are interdependent and indivisible.

 Principle 26—States shall resolve all their environmental disputes peacefully and by appropriate means in accordance 

with the Charter of the United Nations.

 Principle 27—States and people shall cooperate in good faith and in a spirit of partnership in the fulfillment of the 

principles embodied in this Declaration and in the further development of international law in the field of sustainable 

development.

112 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Suggested Reading

Brulle, R.J. 2002. Habermas and green political thought: two roads 

converging. Environmental Politics. 11(4): 1–20.

Callicott, J.B.; Crowder, L.B.; Mumford, K. 1999. Current normative concepts in conservation. Conservation Biology. 13(1): 

22–35.

Dryzek, J.1997. The Politics of the earth: environmental discourses. 

Oxford: Oxford University Press. 400 p.

Ehrenfeld, D. 2002. Swimming lessons: keeping afloat in the age of 

technology. New York: Oxford University Press. 249 p.

Gunderson, L.H.; Holling, C.S., eds. 2002. Panarchy: understanding transformations in human and natural systems. Washington, DC: Island Press. 507 p.

Wilber, K. 1995. Sex, ecology, spirituality: the spirit of evolution. 

Boston, MA: Shambhala. 831 p.

Wondolleck, J.M.; Yaffee, S.L. 2000. Making collaboration work: 

lessons from innovation in natural resource management. 

Washington, DC: Island Press. 277 p.

Worster, D. 1994. Nature’s economy: a history of ecological ideas. 

New York: Cambridge University Press. 505 p.

P A R T I I

Understanding Forest Ecosystems
P A R T I I Key Points

 Biodiversity is a salient feature of forests and depends upon disturbances at a variety of temporal and spatial scales.

	 Temperate forests exhibit common patterns in structure, composition, and development at multiple spatial and temporal 

scales.

 Resilient forests develop complexity through envelopment of 

simpler biotic communities by more complex biotic communities over time, not replacement of one community by another.

 Key processes contributing to biocomplexity in forests include 

disturbances, legacy retention, crown-class differentiation, decadence, canopy stratification, understory development, development of habitat breadth, and niche diversification.

 Management is a human activity designed to meet human goals, 

including preservation of a natural system, recovery of a threatened species, maintenance of biodiversity, or wood production.

 Management based on ecological processes is more likely to be 

successful than management based on simply-defined structural 

conditions.

 Process-based management requires reference conditions, 

benchmarks, and measurable indicators of change.

 Effective management necessitates considerations of multiple 

spatial scales and long periods, including consideration of global 

climate change and human population growth.

 Active, intentional management (AIM) for conservation of nature and sustainable production of economic goods and ecological services is necessary because forests are complex and people 

desire diverse values from forests. AIM is hard to achieve without collaborative learning.

 Resilient forests are high in species diversity and functional 

groups, contain diverse ecological interrelationships, have complex physical and biotic structure, have high biomass (living and 

dead), are spatially heterogeneous, and are internally dynamic.

 Many characteristics of resilient forests depend on regular small 

disturbances, occasional intermediate disturbances, and rare severe disturbances.

 AIMing for resilient forests rests on using planned disturbances 

to help achieve resiliency by promoting diversity, spatial heterogeneity, biocomplexity, and accumulation of biomass.
C H A P T E R 5 

Terms, Concepts, and Theories

Part II of AIMing for Healthy Forests: Active, Intentional Management for Multiple Values provides definitions of ecological terms that 

can facilitate understanding and a discussion of how the science of 

ecology and the art of conservation are inseparable from philosophy, 

especially ethics. Chapter  examines the ecological foundations of 

biodiversity that underlie any conservation effort and provides examples of how these work at the landscape scale and at the scale 

of small forest ecosystems. Chapter 7 begins with a theoretical underpinning for active, intentional management (AIM) based on stochasticity, disturbance, and change. Building on this, the second part 

of the chapter focuses on structure, pattern, and process of forest 

ecosystems and how management of ecological processes is essential 

to AIM. Chapter 8 describes some of the practical and operational 

aspects of AIM. What then might seem missing is a cookbook of 

AIM recipes. But a quick review of this publication in its entirety 

reveals why such a cookbook for a limited region, like the Pacific 

Northwest, is likely to be misleading and result in unintended consequences.

 The region is ecologically diverse, and understanding local ecosystems is key to successful conservation.
118 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

 Active, intentional management must be process based with 

emphasis on (1) diagnosis of current conditions, (2) prognosis 

with and without intervention, (3) an accepted-reference condition and establishment of baseline conditions by which to 

judge progress, (4) use of benchmarks (alternative-management 

approaches) by which to judge success, and (5) choice of metrics by which to evaluate any current state of the management 

system.

 Active, intentional management is itself a social process that depends on good faith in collaborative learning and collaborative 

management. The AIM approach must be fully justified in the 

eyes of all stakeholders and culturally appropriate. A cookbook 

by its nature is pedantic, top-down instructions, or, in holarchical terms, a pathological dominator. In any event, no one I know 

has the knowledge to write a comprehensive cookbook for all 

occasions.

Terminology

Careful use of technical terms is essential to effective communication and developing common understanding. Misuse, abuse, and 

loose use of terms underlie much dissension in ecology and misunderstanding among various people interested in forest management and other environmental issues. For example, habitat is a badly 

abused term. It is used here according to its general definition (the 

place where a member, social group, population, or regional population of a species lives) and more technical definition (the range of 

biotic communities a species inhabits in a landscape or region). 

Thus, a northern spotted owl has its habitat; a pair of spotted 

owls has certain habitat requirements; the elements of the habitats 

of spotted owls on the Olympic Peninsula include nest trees, nest 

groves, roost sites, foraging areas, and so on; and the habitat of 

northern spotted owls in lowland forests of Oregon and Washington is commonly old-growth forest. Habitat quality is best evaluated 

by various demographic measures of the owl—tenure of occupancy, 

longevity of occupants, number of young produced, owl densities, 

proportion of pairs breeding, and so on (fig. 12). Wildlife-habitat 

relationship books document the relationships between each vertebrate species in a region and its associations with plant community 

types, special landscape features, and specific elements of its habitat 

( Johnson and O’Neil 2001). However, there is no spotted owl dispersal habitat (a place where young owls often die), foraging habitat 
C H A P T E R 5 Terms, Concepts, and Theories 119

Figure 12—Two juvenile spotted 

owls. Photo courtesy of USDA Forest 

Service.

(foraging areas are but one element of owl habitat), old-growth 

habitat (it is old-growth forest), wildlife habitat (What is not habitat for some species of wildlife?), or snag habitat (a snag is simply a 

dead tree); “habitat types” are vague—more precise descriptions of 

vegetation are warranted for clear communication.

Vegetation can be described in terms of vegetation zones defined 

by environmental conditions such as temperature, moisture, distance 

from the ocean, elevation, side of major mountain range, and location 

within or among physiographic (landform) provinces. For example, 

the Western Hemlock Zone (Franklin and Dyrness 1973) is a broad 

lowland climatic zone of western Oregon and Washington that includes a variety of forest types characterized by Douglas-fir, western hemlock, western redcedar, and a variety of other trees. When 

referring to widespread, broad types of vegetation, zones are useful: 

Sitka Spruce Zone (along the coasts of Washington and Oregon), 

Western Hemlock Zone (widespread in the lowlands of western 

Washington and Oregon), Mixed Conifer-Mixed Evergreen Zone 

(southwestern Oregon and northern California), and so on. 

There are lists of the numerous forest types for North America 

that are named after dominant trees, but such lists are cumbersome, 

not available to many people, and increasingly obsolete. Common 

tree species, however, can be used to identify common types of forest, 

as they exist in the present; for example, Douglas-fir forest (mostly 

Douglas-fir with other trees scarce), Douglas-fir/western hemlock 

forest, silver fir forest, Sitka spruce/western hemlock forest, and so on. 

Many forest classifications, however, are based on the notion 

of climax types—the type of vegetation community that would develop under idealized stable conditions over the long-term; these 

are often referred to as potential natural vegetation (PNV) types and 

are expressed in terms of dominant overstory trees and key indicator 

plant species that would occur (and do occur in old growth) in the 

understory. They are derived from extensive sampling within vegetation zones and emphasize elevational, topographic, and edaphic 

(soil) relationships. They have been mapped for large areas (for example, Henderson et al. 1989 for the Olympic Peninsula of Washington and Moir 1989 for Mount Rainier). Potential natural vegetation types are only occasionally referred to here, but they do provide 

considerable information on the potential biodiversity of a landscape 

and the quality of growing conditions on a site—often more accurately than the extant vegetation. Easily confused with PNV types 

are plant community types. Plant communities may be grasslands, 

shrub lands, savannahs, forests, and other types and are often named 

after the dominant and key indicator species. They differ from PNV
120 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

types in that, like forest types, they describe extant conditions. In 

this book, descriptors such as Douglas-fir/salal/Oregongrape refer 

to a plant community type, not a PNV, unless otherwise stated.

Forest or community type is not sufficient to describe a forest in a meaningful ecological way. It is important to include a descriptor of seral stage—where along a continuum of development 

of biocomplexity the forest lies. A set of seral stages that are useful 

in describing both natural and managed forests is provided later. 

However, in referring to natural forests broadly, complex forests 

more than 225 years or so old are called old growth (fig. 13). Oldgrowth and complexly structured 80- to 225-year-old forests with 

legacies from old growth simply are called old, natural forest (Carey 

et al. 1992). Any natural forest younger than 80 years old is called 

young forest (Carey and Johnson 1995). When talking about simply 

structured natural forests, the classification provides specific terms. 

Any forest resulting from clearcutting or logging of the majority of 

overstory trees is second growth, whether or not it has been logged 

once, twice, or more than twice, in keeping with the dictionary definition. However, it is wise to avoid using classifications of stands of 

trees—the typical forestry classification based on size of tree and 

wood product quality. Thus, talking about a second-growth Douglas-fir forest in the biomass accumulation stage with implications 

for forest ecosystem function and biodiversity is more informative 

than what a forester might call a large-sawlog Douglas-fir stand 

ready for harvest. For conservation purposes, a stand of trees is only 

a part of a forest ecosystem and forest ecosystems are elements of 

landscapes and landscapes are elements of regions.

Theories, Frameworks, and Points of View

The basic and applied sciences of ecology have had a popular impact unlike that of any other science (Worster 1990). Underlying 

this impact is the hope that this science can offer a great deal more 

than mere data—that it can serve as a pathway to a kind of moral 

enlightenment. Ecology provides understanding (what is), and ethics provides relatedness and relationships (what ought to be)—thus 

there are links between the cognitive-scientific and practical-ethical 

spheres (Rozzi 1999). Garrett Hardin, in his very influential paper in 

Science magazine (Hardin 1968), stated that lack of technical-scientific solutions to problems of human behavior resulted in the arms 

race, unrestrained human population growth, and the tragedy of the 

commons—that individuals will overuse some common resource to 
C H A P T E R 5 Terms, Concepts, and Theories 121

Figure 13—Large fallen trees are 

a common sight in complex forests 

of the Pacific Northwest; such large 

coarse woody debris will provide 

protection and foraging sites for 

amphibians, small mammals, and birds 

for many years to come. Photo by A. 

Carey.

their own gain and to the destruction of that resource at the expense 

of the greater community. E.O. Wilson (1999a) reiterated that environmental problems are innately ethical. Paul Ehrlich (2002) recapitulated these ideas—the cutting edge of environmental science 

has switched from ecological and physical to behavioral with the 

need to alter the course of cultural evolution. The belief of Adam 

Smith (about 1776) that some “invisible hand” redirects individuals 

motivated solely by personal gain to promote the public interest is 

the underlying basis for our present social adoption of laissez-faire 

capitalism. But, the tragedy of the commons has belied the concept 

of the invisible hand for more than a century, as has the history 

of European and Euro-American exploitation of North, Central, 

and South America (Wright 1992). The tragedy of the commons 

is an ecological concept based on the idea that natural selection favors forces of psychological denial—that is, the individual benefits 

from his ability to deny the truth that society as a whole will suffer 
122 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

(Hardin 1968, Ornstein and Ehrlich 1989). Thus, observations of 

unrestrained resource use (mining, overgrazing, pollution, and many 

other examples) and analogous phenomena in nature suggested to 

Hardin that there needs to be a normative concept of mutual coercion mutually agreed upon to produce social arrangements, which 

in turn produce responsibility. In other words, people have to agree 

on what is right and ethical and develop norms of behavior (and 

regulations and laws) that positively reinforce (provide rewards), 

negatively reinforce (provide punishment or threat of punishment), 

and remove obstacles to people acting and cooperating in ways that 

are socially responsible.

Many ecological concepts become normative when applied to 

conservation (Callicott et al. 1999). An example is the tenet that 

morally gross inequities throughout the world are biophysically 

unsustainable—perpetuating poverty has deleterious, irreversible 

impacts on the biosphere and hinders cooperation among parties of 

different socioeconomic status (Daily and Ehrlich 1996). E.O. Wilson (1998) calls for a new unity of knowledge, incorporating biology, social science, ethics, and environmental policy. Yet, he sees the 

greatest challenge to ecology as the cracking apart and resynthesis of 

the assemblages of organisms that occupy ecosystems:

 Accurately and completely describing complex systems.

 Reassembling the descriptions into models that capture the key 

properties of the entire ensemble.

 Measuring success by the power to predict emergent phenomena when passing from general to more specific levels of 

organization.

The important question is, Are there general organizing principles that allow an ecosystem to be reconstituted in full without full 

knowledge of all its component parts (for example, species, genes, 

molecules, and atoms)? Some of this synthesis will be attempted 

here and left to the reader to judge its success.

The ways people (including scientists) dwell in the natural 

world influences the ways they understand, explain, and look at nature. Franklin (1998) says naturalness is the great icon of the environmental community. Angermeier (2000) agrees “most conservationists value naturally evolved biotic elements such as genomes and 

communities over artificial elements,” but states that this judgment 

is not shared by society at large and is based on intrinsic and instrumental values, including respect for nature; furthermore, naturalness is a continuum. Still, Angermeier posits, naturalness is a more 
C H A P T E R 5 Terms, Concepts, and Theories 123

Sidenote 28—Naeem’s 

(2002) Déjà vu conflicts in ecology:

	Does ecosystem or community 

ecology provide better insights 

into the working of nature?

	The relative importance of 

abiotic and biotic factors in 

governing biotic community 

composition

	The virtues of phenomenological vs. mechanistic research

	The relationship between 

biodiversity and stability

	The relative importance of 

taxonomic vs. functional diversity

	The relative strength of 

observational vs. experimental 

approaches

reasonable guide for conservation than ecosystem features such as 

diversity, productivity, and evolution—the foundations for concepts 

such as ecological integrity and ecological restoration. All these concepts are explored here.

Barry Commoner formulated four laws of ecology that proved 

culturally influential but scientifically vague (Partridge 2000) (see 

Part I, sidenote 5). Sagoff ’s antithesis is Nature does not know and 

Nature does not care (Partridge 2000). Thus, the ways people represent nature (e.g., in science models) constitute scenarios that inspire 

attitudes, behaviors, and ways of inhabiting nature. The Darwinian 

metaphor of the tree of life suggests common biological nature and 

origins that people share with all living species—a kinship, an extension of cultural respect beyond our own species, a biocentrism that 

values all life. A metaphor of a web of life suggests the instrumental 

value of biodiversity for human survival requiring an environmental 

ethic of environmental, economic, and utilitarian interdependence 

(Rozzi 1999). Thus, in any ecological paradigm or model there are 

values, assumptions, and worldviews that are often preconscious to 

the modeler and unexplained to the reader. Look and you will find 

some here.

Ecology has pursued an irregular course driven by seemingly diametric views of nature based on 2000 years of science, from the use 

of natural unknowable forces (magic) to biologically based mechanisms (Graham and Dayton 2002, Paine 2002). This course has led 

to debate that forces ecologists to explore how nature works and 

then to generate a synthesis—this cycle of thesis, antithesis, synthesis, and new thesis. Ecologists, however, are divided into subdisciplines that tend to focus on contemporary and emerging questions 

with the concomitant loss of previous synthesis; thus, ecology is a 

science of déjà vu—revisiting major conflicts (Naeem 2002) (sidenote 28). This process has taken place within the lifespan of contemporary ecologists and produced a cacophony that has postmodern 

philosophers denying the objectivity of science (Rykiel 2001). Thus, 

ecology is a mix of theory, empirical observation, worldviews, and 

ethical beliefs. 

Naeem (2002) suggests that no single feature of the Earth’s 

biota is more captivating than its extraordinary taxonomic diversity. 

He presents an emerging paradigm that is a synthesis of community 

and ecosystem ecology which, while concentrating on functional 

versus taxonomic diversity, promises to refocus attention on the 

broader significance of the Earth’s biota. This emerging paradigm 

is that biodiversity governs ecosystem function versus the old paradigm and central tenet of ecology that biodiversity is primarily an 
124 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

This decaying snag, which looks like 

an artist’s sculpture, adds not only 

wildlife value but also aesthetic value 

to an old-growth forest. Photo by T. 

Wilson.

epiphenomenon of ecosystem function and secondarily structured by 

community processes. Neither is correct in an absolute sense—there 

are feedbacks between the two and these are explored here as well.

Paine (2002) is a little more circumspect about paradigms than 

is Naeem (2002). He says ecology has had few paradigm shifts because it is a pluralistic, multiple-causation discipline. Rather, ecology has fads, bandwagons, favored themes, and transient foci of interest that wax, wane, and recover. Bandwagons attract adherents by 

timeliness, vigor, showmanship, and novelty—no one doubts their 

reality or importance, but interests wane as limits to advancement 

increase. Paine says these themes have a common biological heritage—the enormous complexity of natural systems—and share a 

common trait—multiple causation is commonplace and unavoidable. Still, the faddish nature of ecology results in much recycling 

of ideas and concepts under new labels. Often progress is made, for 

example, the evolution of the concept of niches from the Grinnellian (niche as habitat) to the Eltonian (niche as role or occupation) 

to the Hutchinsonian (niche is the multidimensional space occupied 
C H A P T E R 5 Terms, Concepts, and Theories 125

by a species in a biotic community as a result of interactions with 

other species and environmental conditions) (Graham and Dayton 

2002). However, progress is hindered by ecological subspecialization that leads to parallel evolution of concepts, erasure of history as 

contemporary ecologists lose touch with their historical roots, and 

expansion of the scientific literature beyond the cognitive limits of 

individuals. Despite the evolution of niche concepts and the utility 

of the Hutchinsonian niche, the term niche has little agreed-upon 

meaning across subdisciplines in ecology. There are many areas in 

the applied ecological sciences where overreductionism, narrow specialization, and emphasis on single causes and linear relationships 

may be misleading.

This evolution of paradigms in ecology has followed similar upheavals in society and the physical sciences (Barabási 2003, Gleick 

1987, Prigogine and Stengers 1984, Worster 1990). Thus, 18th-century 

beliefs in stability, order, uniformity, closed systems, and predictability have been dispelled. The 19th-century thermodynamic concept 

that the universe is running down with energy leaking out (entropy) 

has been replaced with a Darwinian concept of biological systems 

running up—becoming more organized. And the mid-20th-century 

emphasis on nonequilibrium in natural systems and the primacy of 

stochasticity or randomness is being replaced by an appreciation of 

self-organizing systems that bring order out of chaos. Prigogine won 

the Noble Prize for his work on nonequilibrium systems and dissipative structures. He said Man’s new dialogue with nature should focus 

on two questions: the relationship between disorder and order (e.g., 

evolution) and the reversibility versus irreversibility of entropy (the 

roles of complex, dissipative structures, self-organization, determinism, and chance). Prigogine concludes that the universe is pluralistic 

and complex; structure disappears and appears; some processes are 

stochastic, others are probabilistic; basic processes are deterministic 

and reversible, but natural processes contain essential elements of 

randomness and irreversibility. Key concepts are complexity, nonlinearity, instability, fluctuation, surprises, and self-organization. These 

will be themes of management approaches developed here. Thus, 

we must abandon the hubris of Newton, as described by John T. 

Desaguliers in 1728 (Prigogine and Stengers 1984):

Nature compelled, his piercing Mind obeys,

and gladly shows him all her secret ways;

‘Gainst Mathematicks she has no defense,

and yields t’ experimental Consequence. 
126 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

We must learn to live with ambiguity and uncertainty; we will 

never have perfect predictability; we must let go of simple linear 

models (e.g., 2 + 2 = 4); and we cannot expect nature to reproduce 

her riches after we have extensively disturbed a mix of environmental variables, even if we place an area off limits to future human 

activity.

Any science that conceives of the world as being governed 

according to a universal theoretical plan reduces its various 

riches to the drab applications of general laws thereby becomes an instrument of domination. And man ... sets himself up as its master (Prigogine and Stengers 1984) [italics 

added].

We must rely on some natural processes of self-organization to 

produce adaptive complex systems. Some such natural processes include the tendency to form small tightly bound hubs or subsystems 

loosely connected to one another in networks (Barabási 2003), a 

theme embedded in Panarchy theory. Simply stated, “The disorderly 

behavior of simple systems provides a creative process that produces complexity or richly organized patterns that are sometimes 

stable and sometimes unstable” (Gleick 1987). We can use science 

and learning in understanding processes and heightening the intentionality of our decisions and actions. Like myths and cosmologies, 

science’s endeavor is to understand the nature of the world, the way 

it is organized, and humankind’s place in it, ... the relation of being 

to becoming ... appearance of order out of undifferentiated order 

(Prigogine and Stengers 1984).

Panarchy Theory

Panarchy theory (Gunderson and Holling 2002) is a decentered 

view (divorced from any narrow theory or discipline) that rests on 

the following principles: (1) the universe is composed of systems (interacting groups of things) within larger systems (interacting groups 

of subsystems), ranging from a microscopic soil microcosm to the 

global social-economic-biospheric system; (2) change, indeed surprises, are inevitable; and (3) reorganization after catastrophes resulting from change allows adaptation to the new conditions of life. 

Why is this important? Simon Levin (1999) describes ecosystems as 

dynamic assemblages of interacting components self-organized into 

evanescent patterns of interaction on multiple scales of space and 
C H A P T E R 5 Terms, Concepts, and Theories 127

Sidenote 29—The eight 

commandments of environmental 

management (Levin 1999):

	Reduce uncertainty.

	Expect surprises.

	Maintain heterogeneity.

	Sustain modularity.

	Preserve redundancy.

	Tighten feedback loops.

	Build trust.

	Do unto others as you would 

have them do unto you.

time. Their only essential constant is change. Even the balance of 

nature describes a system far from equilibrium alternating between 

periods of relative stability and periods of dramatic change.

If this were true, then our challenge would be to avoid oversimplifying our definitions of forest ecosystems, to avoid assuming 

that a forest will grow into a particular seral stage no matter what 

has happened or might happen in the future, and to avoid trying to 

manage for or preserve a particular forest condition as if it were static and unchanging. It would mean ensuring our forests have all the 

elements that help them to be resilient after minor surprises (acute, 

or short-term, small to intermediate disturbances), allowing them to 

adapt to changing environmental conditions (slow change or chronic minor disturbances) without suffering catastrophic destruction, 

and when they do suffer catastrophic destruction, to recover quickly 

in a way that maintains the ecological services that we, and all other 

forms of life, need. Levin (1999) offers the “Eight Commandments 

of Environmental Management” (sidenote 29). Part II will explain 

the application of Levin’s suggestions in forest conservation.

C H A P T E R 6

Ecological Foundations of Biodiversity

Forest ecology is about the interactions of organisms with each other and their environment. It follows, then, that forest structure, composition, function, productivity, resilience, and adaptability depend 

on some minimum amount of diversity of organisms available to the 

self-organizing system (Bazzaz 2001, Cardinale and Palmer 2002, 

Holling 1992, Ives et al. 2000, Lindenmayer and Franklin 2002, 

Loreau et al. 2001, Naeem 2002, Naeem and Li 1997, Tilman 1999, 

Tilman et al. 1997, Wardle et al. 2000). Diversity accumulates from 

site-type diversity among small plots within biotic communities to 

the species diversity that describes a biotic community (α-diversity), 

differences between communities (β-diversity), total species diversity in landscapes (γ-diversity), and the floras and faunas of regions 

(Whittaker 1975). Diversity influences ecological processes through 

a variety of mechanisms and different degrees of organization. Genetic diversity operates at the level of local species populations and 

metapopulations. Species diversity strongly influences processes at 

the level of biotic communities and ecosystems. And the diversity 

of biotic communities strongly influences ecological processes that 

operate across ecosystems within landscapes. Different processes affect diversity at different scales, thus, a top-down approach also is 

necessary to fully understand patterns of diversity (Whittaker et al. 

2001). 
130 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

It is sometimes useful to think of diversity as the number and 

distribution of species in Earth’s biosphere, patterns of diversity as 

the varying forms of biotic communities in space and time, and processes of diversity as the dynamic aspects of communities driven 

by both endogenous (internal) and exogenous (external) influences 

(Bridgewater 1988). To make sense of diversity, one must first consider biogeography and what determines the pool of species in a region. The selection of species from the regional pool that are found 

in any particular landscape depends on the characteristics of that 

landscape and landscape-level processes. Within landscapes, biotic 

communities arise with their composition determined by the local 

environment as well as the character of the landscape and its dynamics. Thus, within regions, biological diversity (genes, species, and 

communities) differs in space and over time. Patterns measured at 

small scales, such as within communities, do not necessarily hold at 

larger scales (among communities within landscapes); nor do processes prevailing at small scales necessarily prevail at larger scales 

and vice versa. Consequently, understanding patterns of diversity 

cannot be automatically addressed by scaling locally measured variables to larger areas and longer times or by applying broad patterns 

or general concepts to specific locations. Furthermore, strong components of stochasticity (randomness) and historical events may be 

operating at each spatial scale. Nevertheless, before examining what 

determines the diversity of species and forest communities in forested landscapes and forest-dominated regions, it is pertinent to ask 

why there are so many species?—a question underlying much of 

ecology and evolution (Hutchinson 1959). 

Why Are There So Many Species?

Early theories related diversity to competition (table 9). The more 

alike individuals are, the more likely they compete for limiting resources, and the more likely natural selection promotes traits that 

maximize efficiency of resource exploitation to the extent that individual fitness (reproductive success) benefits. The most intense competition occurs between members of the same species and leads to 

specializations for a limited set of resources, and, under conditions 

of isolation, to speciation. The next most intense competition exists 

between closely related species; such species evolve differences in 

morphological or other characters to more efficiently exploit different resources; for example, bill size differs within and among species 

of Darwin’s finches, and the different finches specialize on different 
Table 9—Theories of biodiversity

Theory Contention

Area Number of species is a result of sampling effort and 

environmental heterogeneity.

History Diversity is a consequence of geologic events, dispersal 

events, and isolation leading to speciation.

Energy Resource-rich environments promote diversity; partitioning of energy among species limits richness.

Stress Benign environments support more species than 

harsh environments; fewer species can adapt to harsh 

environments.

Stability Stable environments support more species; few species 

are able to adapt to varying environments.

Disturbance Disturbance promotes diversity by disrupting competitive interaction.

Interactions Competition, predation, parasitism, and mutualism 

affect niche partitioning.

Source: Adapted from Whittaker et al. 2001.

C H A P T E R 6 Ecological Foundations of Biodiversity 131

sizes of food. Within small homogeneous areas, environmental stability leads to competitive exclusion and reduced numbers of species. As environmental heterogeneity increases within a community, 

niche differentiation, coadaptations, predation, and mutualisms promote increased complexity and diversity (Cohen and Stephens 1978, 

Fretwell 1972, Gilpin 1975, Levins 1968, May 1973). If one defines the 

spaces available for habitation and for interactions among species by 

using a large variety of environmental variables (including area and 

timing of use) that have some importance to one or more species, it 

becomes apparent that a large multivariate space exists within which 

numerous species can exploit various parts (i.e., define their habitat 

by adaptation to critical environmental variables) and within which 

potentially competing species can partition resources through niche 

differentiation (Carey 1981, Hutchinson 1957, Whittaker et al. 1973). 

Similarities among coexisting species are least limiting where productivity is high and seasons are uniform, for example, the Tropics 

(MacArthur 1965). In most environments, disturbances serve to disrupt dynamics of interactions, reduce severity of competition, reduce 

abundances of dominant species, and promote diversity. Small- and 

intermediate-scale disturbances produce heterogeneity within communities that produces preinteractive niche differentiation, wherein 

different niches are available to similar species even before they interact and undergo behavioral or evolutionary change as a response 

to interactions, such as competition, with other species. Catastrophes 
132 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 30—The causeand-effect explanation of population regulation:

	Population regulation does 

entail demographic density 

dependence. 

	Density dependence is necessary, but not sufficient for 

population regulation.

	Competition and predation 

are possible sources of density 

dependence.

	Environmental heterogeneity 

is important in predator-prey, 

host-parasitoid, and host-parasite systems.

	Niche differentiation is important in competition.

	The spatial dynamics of succession and development are 

important in maintaining 

mosaics (environmental heterogeneity).

	Finite dispersal, neighborhood 

interactions, and effects of 

endogenous pattern formation 

are also important.

destroy communities and lead to rapidly changing conditions as 

new communities develop. Proliferation of disturbance-dependent 

species results in species-rich regional flora and fauna (Bridgewater 

1988). Management that homogenizes communities and spreads exotic species can lead to globalization and reduced diversity of native 

flora. Management that includes introductions of exotic domesticated species and marked changes in landscapes (e.g., planting trees 

in the Great Plains) can lead to hybridization of species with an 

overall loss of species diversity (Levin 2002).

Closely related, then, to the questions of why there are so 

many species and how they coexist are questions about what regulates population densities. A population is regulated if it persists 

for generations with fluctuations above zero (Hixon et al. 2002). 

A fundamental tenet of ecology is that population regulation is 

density dependent with negative feedback; in other words, the propensity to increase in size is high when population size is small and 

decreases as the population grows large. Extinction occurs when 

regulatory mechanisms that promote population growth are weaker 

than disruptive events (disturbances) or stochastic variation. As with 

diversity, ecologists examining regulation first focused on competition, then moved on to disturbances such as predation, and then to 

the concept of metapopulations that are demographically open to 

immigration and emigration and that can persist without density 

dependence. As in all debates in ecology, the discussion spiraled 

from alternative simple explanations of population regulation to a 

greater understanding of the complexity of cause and effect (sidenote 30). The bottom line is that population regulation is a truly 

community-level phenomenon (Connell and Orias 1964, Hixon et 

al. 2002, Hutchinson 1978) and, thus, necessarily intertwined with 

species diversity.

Frank Preston (1969) noted that “every naturalist from Darwin 

downwards has felt aggravated that a few species are very common 

and most are rare.” The number of species and number of individuals 

per species in a functional group or biotic community appear to follow a log-series distribution (Fisher et al. 1943). Indeed, the lognormal distribution has emerged as the distribution underlying commonness and rarity (Preston 1948, 1960, 1962a, 1962b, 1969, 1980, 

1981) and many other biological phenomena (Limpert et al. 2001). 

Sugihara (1980) concluded there is a minimum form of community structure involving hierarchically related niches; that niche apportionment is multidimensional, produces evolutionary ecological 

considerations, and results in species diversity; and that the end result is lognormal species abundance patterns. The practical import of 
0

5

10

15

20

25

30

35

40

<1 2 4 8 16 32 64

Number of bird species

Percentage of total individuals

C H A P T E R 6 Ecological Foundations of Biodiversity 133

Figure 14—The distribution of 

occurrence in diurnal forest birds in 

the Oregon Coast Range (adapted 

from Carey et al. 1991) approximates 

a lognormal distribution; lognormal 

distributions characterize commonness 

and rarity in many biological phenomena.

the lognormal distribution is that with any sample of a large number 

of species, only a few species can be expected to be abundant; many 

will be rare (fig. 14). Thus, rarity is not necessarily indicative of poor 

or degraded environmental conditions, rather it is the rule. However, species do not necessarily retain the same relative abundances 

through time—environmental change (slow, fast, acute, or chronic) 

and stochastic (random) events affect different species differently. 

For example, in an experiment in increasing spatial heterogeneity 

in the canopy of second-growth forests (Carey et al. 1999d), native 

plant species diversity increased by 150 percent with concomitant 

changes in relative abundance (Thysell and Carey 2001a), species 

of litter invertebrates changed in relative abundance within functional groups at fine scales in response to treatment (Schowalter et 

al. 2003), the overall diversity and relative abundances of hypogeous 

and epigeous fungi on the forest floor increased (Carey et al. 2002), 

the diversity and abundance of winter birds increased (Haveri and 

Carey 2000), and rarer mammals increased in abundance (Carey 

2000b, Carey and Wilson 2001). Many of these changes probably 

were due to changes in relative abundances and increased abundance 

of rare species in response to changes in environmental variables, but 

perhaps with some changes owing to germination of dormant seeds 

and to immigration (e.g., by ruderal plants and birds from surrounding areas). These changes illustrate that the simple number of species (often referred to as species richness) is inadequate to describe 
A B

C

134 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 15—(A) An adult northern 

spotted owl and (B) a bushy-tailed 

woodrat. Photos courtesy of USDA

Forest Service. (C) Two Burrington 

jumping slugs. Photo by J. Ziegltrum.

the diversity of a community. Other useful measures include the 

numbers of species each accounting for, say, more than 5 percent of 

individuals, changes in the rank order of species, and changes in the 

ranks of individual species on a lognormal scale (Carey et al. 1991, 

Carey and Johnson 1995). The degree to which individuals are equally apportioned among species is called evenness. Increasing richness 

and evenness are not necessarily indicative of improving conditions 

for native diversity—these changes could reflect decreased overall 

abundance, invasion by exotic species, or replacement of rare or specialized species by common or generalist species. Comparing the 

structure of a biotic community in a relatively undisturbed natural 

environment to that in an environment under marked human influence provides a measure of the biotic integrity of the human-dominated environment (Karr 1991, 1993) and may indicate the relative 

sustainability of alternative management regimes in forests (Carey 

and Harrington 2001, Carey and Johnson 1995).

Relative rarity also increases with levels in food webs. Species at 

the tops of food chains—predators (fig. 15A)—are rarer than those 

they prey upon (fig. 15B) and nonpredators in general, including 

macroinvertebrate predators in Mollusca (fig. 15C), Annelida, and 

Arthropoda (Ahlering and Carrel 2001). For example, limited sampling in the Missouri Ozark Mountains found all 3 phyla, 8 classes, 

19 orders, and 62 morphospecies with 28 percent of detected species 

being predatory but only 9 percent of individuals belonging to those 

species. Rare species are less likely to be detected during sampling 
C H A P T E R 6 Ecological Foundations of Biodiversity 135

Figure 16—A rock crawler on 

Carpenter Ridge in the Sierra Nevada 

mountains, California. Photo by A. 

Wild © 2003.

for diversity than common species, and it is difficult to establish the 

absence of a species. This problem of sampling is confounded when 

rare species are cryptic, very small, evasive, or inhabiting environments inimical to people—difficult to find even when present. Few 

scientists have studied stygofauna—inhabitants of caves and ground 

water—yet these species are numerous: 1,000 protozoa, 3,000 crustacea, 590 arachnids, 106 vertebrates (92 frogs), perhaps a total of 

7,000 species (Gibert and Deharveng 2002). Nevertheless, rare species are more subject to local extinction than abundant species. Thus, 

expectations should be low that any particular rare species would be 

found in any limited sample of individuals or areas. Care must be 

taken to ensure the curve of species accumulation with increasing 

sampling effort has reached an asymptote before estimating total diversity for any particular group of species or narrowly defined community (group of species); it is much easier to detect differences in 

the distribution of individuals among species, the number of species 

per a large sample of individuals, the number of species for a specific 

area sampled, or the structure of the narrowly defined community. 

This profound characteristic of commonness and rarity of species 

has obvious important implications for reserve strategies, conservation goals, effectiveness monitoring, and choice of indicators.

Most of the estimated 4 to 112 million extant species have yet to 

be described and given a name (Wilson 1999a). Perhaps 98 percent 

of birds are known, 1.5 percent of algae, and less than 1 percent of 

bacteria. Questions about the effects of human activities on littlestudied groups are literally endless. Little is known about the Grylloblattids (cockroach-crickets). These primitive insects, without wings 

or eyes, were discovered in Canada 

in 1911 and are known as ice bugs, 

ice crawlers, and rock crawlers 

(Grylloblatta spp.). They are found 

almost exclusively on mountains 

higher than 500 meters in Russia, 

China, Korea, Japan, and North 

America; endemism (species found 

only in one biogeographic area) is 

high in North America (fig. 16). 

Their preference for low temperatures (ca 4° C) slows their development—3 years may be required for 

eggs to hatch and 7 years to reach 

maturity. There are fewer species 

(25) in this order-suborder than 
136 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 31—Biodiversity 

according to Blondel (1987):

 Biological systems are temporal as well as spatial; they 

always reflect a history from 

glaciation to human land use 

changes.

 Geologic time and processes (plate tectonics, climate 

change, and glaciation) join 

and separate faunas and floras.

 Evolutionary time produces 

genetic changes in populations 

through natural selection.

 Ecological time produces 

changes in communities with 

ecological succession and community development.

 Evolutionary convergence 

at the level of communities 

is hard to distinguish from 

phylogeny.

 Mechanisms of community 

organization differ between 

primeval and human-dominated landscapes because of 

reduced diversity:

 Size of any local population 

not at equilibrium is determined by local resource 

conditions.

 Species distributions are 

broken into a mosaic of 

local populations which 

exchange propagules in 

accordance with local 

demographic conditions.

 The prime factor affecting transfer between 

local populations in the 

same neighborhood is the 

specific disturbance regime 

and the mosaic it produces.

 Evolutionarily, a metapopulation (the local populations of a mosaic of biotic 

communities) promotes 

genetic diversity and polymorphisms in response to 

disturbance regimes, predation, and competition.

any other order of insects. They live in environments where arthropod diversity is low. Many live on snowfields and glaciers and feed 

on other insects frozen on the surface of the snow or ice. One species has been found on glaciers on Mount Rainier, the tallest (about 

4,400 meters) volcanic peak in the continental United States, sitting 

astride the Cascade Range in Washington and another species on 

the relatively low Mary’s Peak, devoid of snowfields and glaciers, just 

west of Corvallis, Oregon. Studies in British Columbia, however, 

showed them to be widespread, with an affinity for edges between 

forests and clearcuts (Huggard and Klenner 2003). 

 Corliss (2001) asked “Have the Protozoa been overlooked?” in 

biodiversity calculations. He relates that more than 213,000 protists, 

including 92,000 protozoa, are important pathogens (causing diseases including malaria, sleeping sickness, leishmaniasis, and many 

others), help control bacteria, and contribute to nutrient turnover. 

Eimeria spp. are common protozoan intestinal parasites of small 

mammals in North America. Studies of small mammals easily 

uncover new species of endoparasites such as Eimeria (Fuller and 

Duszynski 1997, Torbett et al. 1982); new range records of ectoparasites, such as fleas (Main et al. 1979); new species and geographical occurrences of the smallest forms of life-like viruses (Main and 

Carey 1979, 1980); even new range records of the small mammals 

themselves (Carey 1978a); and incidentally, new records of rarer organisms such as achlorophyllous mycotrophs (Thysell et al. 1997a). 

A team of scientists (Memmott et al. 2000) examined the food web 

of one common plant species in England—scotchbroom—now an 

introduced pest species of growing importance in Washington (Carey 2002a). They identified 154 taxa in a food web with 370 trophic 

links: 19 herbivores, 66 parasitoids, 60 predators, 5 omnivores, and 3

pathogens with a total 82 functional groups, 9 orders of insects, plus 

vertebrates, arachnids, bacteria, and fungi. There is no end to biodiversity. Forest ecologists have just scratched the surface of biological 

diversity; they rarely consider parasites and pathogens, even though 

forests play important roles in maintenance of diseases of people, 

such as Lyme Disease and its tick vectors (Carey et al. 1980a, 1981).

Biogeography

Biogeography refers to the diversity of organisms and the regulation of diversity in heterogeneous and changing environments. It is 

now well understood that patterns and processes in diversity must 

be considered in reference to space, time, and change—and that 
C H A P T E R 6 Ecological Foundations of Biodiversity 137

 Humans have played important and diverse roles in 

determining biogeography.

 A complicated network 

of interacting factors has 

determined the present 

distribution and abundance 

of species.

these three dimensions are inextricably linked. Neither deterministic (cause-and-effect) nor stochastic (random effects) paradigms are 

sufficient for understanding biogeography; ecologists need biological realism and multifaceted, interactive approaches to comprehend 

ecological systems; thus, hierarchy theory is essential to understanding biogeography and biodiversity because it bridges biogeography, 

ecology, and evolution (Blondel 1987) (sidenote 31). 

Regional diversity (regional species pool, biotic communities, 

and life zones) is determined by long-term global processes and 

the resulting biogeography. Historically, theories of diversity have 

not addressed clearly components of general diversity or dealt adequately with geographical scale (Whittaker et al. 2001). Thus, α-, β-, 

and γ diversities are used ambiguously—the terms local, landscape, 

and regional diversity are more intuitive. Moreover, inventorying all 

species is difficult, if not impossible, and knowing how heterogeneity of environmental factors differs with scale is prerequisite to 

evaluating differences in diversity at local, landscape, and regional 

scales (Endler 1977). Thus, a top-down approach is important to understanding patterns of diversity (O’Neill et al. 1986). For example, 

there is a grand cline globally, with low diversity at the poles and 

high diversity in the Tropics. Plate tectonics, continental uplift, volcanism, glaciation, global climate change, mass extinctions, replacement of higher taxa (e.g., placental mammals by marsupials), and 

wind and river erosion and deposition have profoundly affected patterns of species occurrences. Historical contingencies operate at every scale. Tausch et al. (1993) refer to the “Legacy of the Quaternary” 

(0 to 2 million years ago), with its 24 glacial events and interglacials 

producing spatially and temporally variable climates and instability 

in plant communities with species composition constantly changing. Others have drawn similar conclusions after examining paleoecological or biochronological sequences (Gagosian 2003, Hallett et 

al. 2003, Johnson and Mayeux 1992, Millar and Woolfenden 1999, 

Pielou 1991). They warn against trying to recreate presettlement vegetation—it may not be feasible. Pielou (1991) stated “At no time has 

there been a return to ‘things as they were.’” Furthermore, the future 

will be different from the past.

Humans have been an overriding influence on biogeography, 

from exterminating the largest North American mammals 11,000

years ago to using fire to manage the natural environment; bringing 

about large-scale vegetation change with grazing and agriculture; 

purposefully and accidentally introducing novel plants, diseases, insect pests, and vertebrates into vulnerable ecosystems; using persistent toxic chemicals in agriculture, forestry, and manufacturing; 
138 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 17—Forty-eight percent 

of Oregon and Washington is covered 

by forest—approximately 20 million hectares or 78,000 square miles. 

Graphic by D. Olson.

polluting air, water, and soil; and changing the global climate 

(Blondel 1987, Bonnicksen et al. 1999, Diamond 1998, Krech 1999, 

Palumbi 2001, Pyne 1997, Wright 1992). 

The amount of forested area in the United States increased from 

1952 to 1963, peaking at 309 million hectares, and then declined to 

303 million hectares by 1997—a loss of 6 million hectares, or 2 percent (roughly the size of West Virginia); current projections suggest 

another 3 percent loss (9 million hectares) in total area, including a 

4-percent loss of privately owned forests by 2050 (Alig et al. 2003). 

Along the Pacific coast, the 92 million hectares of forest existing 

in 1953 is expected to decline to 84 million hectares in 2050—a 9-

percent decline (almost half the size of Washington state); however, 

private forests will decline from 34 million to 28 million hectares—a 

decline of 17 percent owing to land use changes (fig. 17). The climate 

change hypothesis predicts that the geographic range of forests will 

shrink owing to catastrophes or dieback and will be replaced by 

grasslands (Loehle 2000). Mote (2003) reports that temperatures 

and precipitation in the Pacific Northwest in the 20th century increased at rates higher than the global average, with effects on flora 

and fauna. Global climate change, changes in regional climates, and 

changes in land use by people have strong effects on species, biotic 

communities, and even biomes (Hansen et al. 

2001). Climate has a strong influence on PNV

and natural disturbance regimes. 

Biogeographic diversity includes endemism and taxonomic distinctiveness, whereas 

local diversity focuses on numbers of species 

and distribution of individuals among species. 

The two are not necessarily positively correlated. For example, the Olympic Peninsula of 

Washington joined the mainland of North 

America because of plate tectonics but remained ecologically relatively isolated; thus, 

the peninsula has both numerous examples 

of endemism (at high elevations) and high 

diversity locally (at low elevations) and regionally across the peninsula, owing in part 

to a dramatic precipitation gradient. For example, tree crowns on the western peninsula 

may harbor 77 species of epiphytic plants, 

and tree boles may support 70 epiphytes. The 

endemic Roosevelt elk influences both forest 

structure and succession, reducing shrubs and 
C H A P T E R 6 Ecological Foundations of Biodiversity 139

Figure 18—A bull Roosevelt elk. 

Photo by A. Carey.

promoting grasses (fig. 18). The magnificence of the elk and the forest caused President Grover Cleveland to set aside 891,000 hectares 

as the Olympic Forest Reserve in 1897; in 1907, President Teddy 

Roosevelt created the Mount Olympus National Monument; and 

in 1938, President Franklin Roosevelt created the Olympic National 

Park (Sharpe 1956). Islands, on the other hand, may have high endemism but few species (MacArthur and Wilson 1967, Whittaker et 

al. 2001). The mammalian fauna of the archipelago of southeastern 

Alaska provides a Pacific Northwest example of high endemism and 

few species.

Residual historical patterns from geologic history, climate, and 

physiography (e.g., biogeographic barriers such as mountain ranges, 

deserts, large rivers, and oceans) explain much of regional diversity. 

Western North America has 95 floristic associations each characterized by a flora, biogeographic range, and bioclimatic conditions. 

Washington and Oregon comprise 15 physiographic (landform) 

provinces, each containing multiple vegetation zones (Franklin and 

Dyrness 1973). Successional and developmental patterns differ significantly among the zones. Multiple types of biotic communities 

occur within each zone, with a total of almost 400 types. Johnson 

and O’Neil (2001) linked 541 species of indigenous vertebrates to 85

types of vegetation cross-classified by 26 forest structural conditions

and 20 shrub- and grassland-structural conditions in Washington 

and Oregon (table 10). 

The area west of the Cascade crest in Washington and Oregon 

contains nine major physiographic provinces, a dozen vegetation 

zones, and four major biogeographic barriers (the alpine of the Cascade Mountains on the east, Puget Sound in north-central western 

Washington, the Pacific Ocean 

on the west, and the Columbia 

River separating Washington 

(north) from Oregon (south). 

Soils range from serpentine inclusions in the south to uplifted 

marine sediments, volcanic ash, 

volcanic basalts, outflows of material from the bursting of glacial 

dams on Lake Missoula in distant 

Montana, glacial moraines, glacial 

outwash plains, colluviums, and 

alluviums with organic matter 

practically absent to deep layers 

of humus, litter, and coarse woody 
Table 10—Examples of wildlife habitat relationships in Oregon and Washington forests

East-side species occurrences and forest types:

Taxon Mixed conifer Lodgepole pine Ponderosa pine Upland aspen

Amphibians 12 9 13 4

Reptiles 11 12 21 5

Birds 116 83 131 77

Small mammals 43 26 31 24

Bats 11 9 15 5

Carnivores 18 13 14 10

Ungulates 9 8 7 5

All species 220 160 232 130

Source: Sallabanks et al. 2001.

West-side species occurrences and structural stages:

Taxon Grass/forb Shrub/seedling Sapling/pole Giant trees

Amphibians 19 19 20 28

Reptiles 19 16 16 17

Birds 61 92 98 140

Mammals 66 65 64 78

Source: Olson et al. 2001.

West-side species occurrences and habitat elements:

Amphibians Reptiles Birds Mammals

Rock/talus 3 10 27 35

Fallen trees 12 5 18 50

Duff/litter 10 4 5 19

Moss 1 0 5 4

Snags 4 0 57 22

Shrubs 1 0 21 11

Live trees 3 0 72 37

Source: Shield et al. 2002.

140 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

debris (standing dead trees, fallen trees, stumps, and large tree parts), 

depending on locale and management history. 

The area is characterized by wet, mild winters, cool, dry summers, and a long frost-free season. During all seasons, prevailing 

westerly winds are moist. Climatic diagrams show typical Mediterranean curves, but summer fog provides about 200 millimeters 

of additional water and extended periods of cloudiness that reduce 

evaporation. During the 20th century, the region became significantly 

warmer (by 0.9 °c) and wetter (14 percent wetter), warming at a rate 

faster than the global average (Mote 2003). The vegetation spans 

the gamut from Mediterranean types in the Mixed-­Conifer/Mixed 
A

B

C

D

E

C H A P T E R 6 Ecological Foundations of Biodiversity 141

Figure 19—Vegetation variations of the Pacific Northwest: (A) 

redwoods of northern California; (B) 

oak grasslands near Corvallis, Oregon; 

(C) Mount Rainier, Washington; (D) 

coastal conifers along the western 

edge of the Olympic Peninsula; and 

(E) towering Sitka spruce and western 

redcedar in the Hoh Rainforest. Photos by A. Carey.

Evergreen Zone in the south (fig. 19A) to Idaho fescue grasslands 

and oak woodlands along the Rogue, Umpqua, and Willamette 

River valleys and the Puget Trough (fig. 19B) to subalpine fir, alpine 

meadow, and 27 glacial systems on Mount Rainier up 4,400 meters 

above sea level (fig. 19C) to sand dunes and shore pine at the ocean 

edge (fig. 19D) to conifer rain forests near sea level on the Olympic 

Peninsula (fig. 19E) (Daubenmire 1978, Franklin and Dyrness 1973, 

Peinado et al. 1997).
142 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

In Pacific North America, there are four major physiognomic 

groups of forests plants: 

 Sclerophylls—367 taxa in oak forests and chaparrals. 

 Acicular—187 taxa in upland interior forests of true fir, pine, 

sequoia, juniper, and some oak groups.

 Temperate—315 taxa in forests of redwood, western redcedar, 

western hemlock, subalpine fir, and Douglas-fir.

 Boreal—237 taxa. 

Not only is the Olympic Peninsula a hotspot of endemism, the 

entire Pacific Northwest has a number of well-known vertebrate 

endemics, including Keen’s mouse, Douglas’ squirrel, Townsend’s 

chipmunk, mountain beaver, red tree vole, and shrew-mole—the 

latter three genera are unique to the Pacific Northwest. Among 

birds, the northern spotted owl is a well-known subspecies unique 

to the Pacific Northwest. There are also more than 62 species of reptiles and amphibians, with more added as their taxonomy is revised 

and expanded (Leonard et al. 1993, Nussbaum et al. 1983); endemics 

include Cope’s giant salamander, the Oregon slender salamander, 

Larch mountain salamander and others, including some endemic to 

the greater Northwest, such as the tailed frog. The transition from 

the Western Hemlock Zone to the Mixed-Conifer Zone is a zone 

of speciation for chipmunks and red tree voles. 

The first sawmill in Oregon was established in 1829, and there 

were 173 mills by 1870. Large catastrophic disturbances occurred 

during the 20th century (e.g., the 1933 Tillamook Burn consumed 

over 97,000 hectares, and the 1962 Columbus Day Storm blew down 

6 billion board feet of timber). Despite widespread logging, natural 

catastrophes, human-caused fires, and human settlement, western 

Washington and Oregon are still dominated by forests. Western 

Oregon is 80 percent forested with 52 percent federal, 41 percent 

private, and 7 percent state forest. However, of this forested area, 

78 percent is less than 120 years old. Western Oregon does have 3.7

million hectares of wilderness (Campbell et al. 2002). Historically, 

the primary catastrophic disturbance in western Washington and 

Oregon has been fire. In Douglas-fir/western hemlock, Pacific silver 

fir, and subalpine forest types, fires have been of high severity but low 

frequency, and in mixed evergreen, dry Douglas-fir, and red fir forest types, fires have been of moderate severity and frequency (Agee 

1998). Additional large-scale-disturbance windstorms (e.g., the 1921

blow in Washington) and smaller scale-disturbance ice storms have 

been relatively uncommon, and forest grew to ages of 250-, 500-, or 

1,000 years or more. 
C H A P T E R 6 Ecological Foundations of Biodiversity 143

Figure 20—Basalt cliffs line the 

edge of the Salmon River, Idaho, and 

provide a stunning backdrop for recreational activities, such as kayaking. 

Photo by A. Carey.

Figure 21—Dwarf mistletoe. 

Photo by A. Carey.

On the east side of the Cascade Range of Oregon and Washington, massive basalt flows covered with volcanic ash extend to the 

Salmon River in Idaho where they abut uplifted marine sediments 

(fig. 20). Mountains to the east and west form a large basin with 

borders of strong moisture gradients and dissected by long rivers, 

with the Columbia River predominant. Vegetation is diverse owing to the variety in climate, geology, landforms, hydrology, flora, 

fauna, and disturbances by fire, insects, pathogens, and water (Hessburg et al. 2000). Differences in physiography, lithology, topography, 

geomorphic processes, and climate produce broad-scale patterns; 

environmental gradients, successional and developmental dynamics, 

and patch-scale disturbances produce meso-scale patterns. Forests 

dominate to the north and on the slopes and foothills surrounding 

the basin and have increased in the Blue Mountains, Columbia Plateau, and Upper Snake River with fire suppression. Precipitation has 

increased markedly (by 38 percent) in the north-central area in the 

20th century (Mote 2003). 

Hemstrom (2001) emphasized that not only are vegetation patterns a result of such environmental variation and disturbances at 

multiple scales, but also that vegetative patterns influence the amount, 

severity, and distribution of disturbances by insects, pathogens, and 

fire. Numerous bark beetles (Hayes and Daterman 2001) and insect defoliators (Torgersen 2001) have major impacts on the forests. 

Root diseases are common (Thies 2001) as are dwarf mistletoes (fig. 

21), rusts, and stem decays (Parks and Flanagan 2001). Historically, 

fire tended to occur at higher frequencies and lower severities (but 

still at scales of more than 10,000 hectares) compared to west-side 

forests (Agee 1998). Well before the arrival of settlers from the east, 

less than 3 percent of east-side forest was old growth, and it was in 

isolated patches (Youngblood 2001) (fig. 22). Thus, it appears that 

east-side forests exhibited a relatively fine-scale mosaic of different 

communities and developmental stages (intercommunity mosaic) 

compared to a relatively fine-scale developmental (intracommunity) 

mosaic in west-side forests. 
144 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 22—East-side forests: an 

isolated old-growth patch near Sisters, 

Oregon. Photo by A. Carey.

Today, advanced forest succession and associated accumulations 

of biomass are increasing vulnerability of forests to catastrophic 

disturbances by insects, diseases, and fires (Tiedemann et al. 2000) 

(fig. 23). This region has high floristic diversity, with many endemics 

adapted to disturbance, owing to its complex biophysical environment (Croft 2001). Similarly, many of the indigenous vertebrates are 

disturbance adapted, benefiting from mosaics, including lynx, wolverine, and fisher (Bull et al. 2001) and a number of birds, especially 

those dependent on dead trees, including seven species of woodpeckers and nuthatches (Bull and Wales 2001b); seven amphibian 

species are of conservation concern and sensitive to disturbance 

(Bull and Wales 2001a). 

Current vegetation patterns are a result of the interactions of 

grazing, timber harvest, tree planting, fire suppression, and lack of 

active management after planting, and topographic position. Ridge, 

slope, footslope, plains, and toeslopes all historically supported 

different communities (late-seral single-layer forest, early-seral- 
C H A P T E R 6 Ecological Foundations of Biodiversity 145

Figure 23—An example of a lowintensity fire in a west-side secondgrowth forest. Photo courtesy of the 

USDA Forest Service.

midseral forest mosaic, late-seral multilayer forest, late-seral singlelayer forest, and midseral broadleaf-tall shrub mosaic, respectively) 

(Hemstrom 2001). Resource management has produced late-seral 

multilayer and early-seral mosaics on most sites with increased intertree competition, competition stress, increased susceptibility to 

insect attack, pathogens, and fire, and a switch from local to broadscale disturbance patterns that changed not only patterns of plant 

species but vertebrates as well. 

Human and natural disturbances may well have changed some 

ecosystem processes; for example, loss of a successional mosaic with 

actinorhizal shrubs (snow brush and bitter-brush) that normally replenish soil nitrogen lost by fire through nitrogen fixation could lead 

to long-term nitrogen depletion and reduced productivity (Busse 

2000). Anthropogenic disturbances have also displaced native biotic community types and reduced productive potential for 17 or 

more PNV types, especially salt desert shrub, Wyoming big sagebrush/warm basin big sagebrush, mountain big sagebrush/mesicwet, mountain big sagebrush/mesic-wet with juniper, and wheatgrass grasslands, making it difficult or impossible to restore these 

ecosystems to historical conditions. Major sources of change include 

livestock grazing, invasive species, changes in fire regimes, and climate change (Bunting et al. 2002). Hessburg et al. (2000) summarized the salient changes: decline in shrub land, loss of herb land, 

shift from early- to late-seral species, decline in western white pine 

in Idaho and Montana, dominance by shade-tolerant conifers in the 

Great Basin, and loss of patches with old-forest character.
A

B C

146 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 24—Effects of management: (A) exclosures show the strong 

effects that ungulates have on grasses; 

(B) a heavily grazed second-growth 

forest in eastern Oregon, and (C) a 

chipmunk finds its space among a 

burned log, thistle seeds, and disturbance-adapted plants. Photos by A. 

Carey.

These kinds of changes are common in interior western North 

America (fig. 24). For example, in the Targhee National Forest in 

Idaho, logging, grazing, and fire suppression prompted a transition 

from a fire-driven mosaic of grass, shrub, broadleaf, and mixed-forest community types to a conifer-dominated landscape—aspen declined from 37 percent to 8 percent, and conifer forests increased 

from 15 percent to 50 percent of the landscape. The problems here 

are not ones of fragmentation but increasing patch sizes and reduced disturbance frequencies reducing the diversity of communities in the landscape (Gallant et al. 2003). 

Thus, at the landscape scale, topography, soils, disturbance regimes, tidal dynamics (in coastline landscapes), linked series of 
C H A P T E R 6 Ecological Foundations of Biodiversity 147

Disturbance 

has long been 

recognized 

as a primary 

underpinning of 

biological diversity 

in landscapes.

events, management regimes (the nature of the shifting steady-state 

mosaic of a regulated forest), and cumulative effects of management 

activities are important. At local scales, microenvironmental variation, 

intermediate disturbances, community dynamics, patch dynamics, 

and management activities are important. However, Blondel states 

that “Since processes which produce biological diversities operate 

differently, and at different rates ...along the scales of space, time, 

and change, many theories ... are ... more complementary than conflicting” (Whittaker et al. 2001).

Landscape Ecology

Diversity in a landscape will result from (1) natural random sampling 

of the regional species pool (Hubbell 2001) and (2) a variety of deterministic factors and processes operating at various scales including 

topographic, climatic, and edaphic diversity, history of disturbances 

(frequency, intensity, spatial extent, duration, and variance in times 

since disturbance), structural and biological legacies retained after 

disturbances, distances from sources of colonizers for various species, the vagility (dispersal ability) of those species, and the dynamics of biotic communities (reorganization, succession, development, 

creative destruction). Disturbance has long been recognized as a primary underpinning of biological diversity in landscapes because it is 

a major determinant of spatial heterogeneity at multiple scales (Bormann and Likens 1979, Canham et al. 1990, Carey et al. 1999c, Connell and Slatyer 1977, Foster et al. 1998, Franklin et al. 2002, Levin 

and Paine 1974, Oliver 1981, Petraitis et al. 1989, Pickett 1976, White 

1979, Whittaker 1975). Examples of large, infrequent disturbances 

include the 1938 Northeast hurricane, 1980 eruption of Mount St. 

Helens, 1993 Tionesta tornado, 1998 Yellowstone fire, and the 1993 

Mississippi floods (Foster et al. 1998). The resulting landscape patterns were controlled by interactions among the specific disturbance, 

the abiotic environment (especially topography), the vegetation at 

the time of disturbance, and the enduring legacies left by the disturbance. Northern coniferous forests are characterized by infrequent 

stand-replacing fires driven primarily by climate, strongly influential 

of plant population structure, genetics, and evolution, and inducing spatial heterogeneity (Turner et al. 2003). Spatial heterogeneity 

was more important than any other single environmental variable in 

explaining the abundance of mule deer in California—fine-grained 

mosaics with abundant edges, irregularly shaped patches, and high 

fractal dimensions allowed deer to exist within small home ranges 
148 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 25—A patchy landscape 

dominated by clearcuts. Photo courtesy of USDA Forest Service.

(Kie et al. 2002). Heterogeneity among communities in the landscape generally increases the number of species in the landscape. For 

example, canopy cover gradients promote diversity of larval amphibians and coexistence of spring peepers and wood frogs in forests 

(Skelly et al. 2002). 

Not all disturbances create complexity and heterogeneity, and 

not all heterogeneity promotes diversity. Traditional clearcutting, for 

example, produces regeneration sites that are as uniform as possible 

(fig. 25). When followed by planting (and often herbicide application), a simple monoculture with reduced diversity may result. In Pacific Northwest forests, most forest species are found in old-growth 

forests, but both managed and natural forests in closed-canopy stages from 30 to 200 years old may have markedly reduced diversity. 

Landscapes managed under short-rotation timber management may 

have increased abundances of exotic and ruderal species and markedly decreased diversity of native species (plants, fungi, and animals) 

(Carey 2003a, 2003b, 2003c; Carey et al. 1999c, 1999d). With short 

rotations and intentionally simplified stands of timber, whatever 

complex forest is left in the landscape is highly isolated from other 

complex forests and will remain so for quite some time (a century 

or more) even if management for timber stops. Such a landscape 

suffers from both loss in area of complex forests and fragmentation. 

For example, clearcuts less than 12 years old in British Columbia 

are significant barriers to dispersal of red-legged frogs, depending 

on weather and body mass of the frog. The warmer and drier the 

clearcut, the less permeable the clearcuts become because of physiological constraints on frog respiration (Chan-McLeod 2003). 

Clearcuts may also be hostile environments for California redbacked voles because of lack of moisture, food, and cover (Clarkson 

and Mills 1994, Hooven and Black 1976, Mills 1995, Tallmon and 

Mills 1994), and for Douglas’ squirrels and northern flying squirrels because of lack of trees. Closed-canopy competitive-exclusion 

forest communities with their sparse understories are inimical to 

Townsend’s chipmunk, Keen’s mouse, Oregon creeping voles, and 

a variety of other mammals. When rotations are short (say under 

40 years), more than 25 percent of the landscape would be maintained in inhospitable conditions for animals of various life histories 

(Carey et al. 1999d). Thus, the life history of a species, the nature of 

the ecotones (a transitional zone between two communities containing the characteristic species of each), and the contrasts between 

juxtaposed communities determines the ecotone’s degree of permeability and function as a boundary between communities—in other 

words, whether a hospitable mosaic is being maintained or whether 
C H A P T E R 6 Ecological Foundations of Biodiversity 149

the habitat of some species is being fragmented (Cadenasso et al. 

2003a, 2003b). 

Ecotones—loosely referred to as edges or boundaries—influence the flow not only of organisms but also materials and energy 

through mosaics. It is important to note that this is often a two-way 

flow—not only can a clearcut or field influence the microclimatic 

environment (light, temperature, and moisture) of a forest (Chen 

et al. 1995), but the reverse can happen also (Cadenasso et al. 1997). 

These edge effects (alteration of environmental conditions by the 

presence of a boundary or ecotone between two relatively homogeneous and usually contrasting environments) arise whenever areas 

are partitioned into patches, naturally or anthropogenically. Care 

must be taken, however, not to treat them as static; they are often 

rapidly changing in forested landscapes. Edge effects differ with 

disturbance regimes, time since creation, development of a sidewall 

of vegetation, successional or developmental state, and topographic 

position. Ecotones are complex three-dimensonal (at least) zones 

characterized by both above- and belowground gradients. These 

gradients exist even in the fine-scale mosaics with openings of 0.0 

to 1.0 hectares (York et al. 2003). A tenfold increase in area of opening can produce a 34-percent increase in height growth of seedlings 

in gaps. Linear discontinuities such as narrow roads may not drastically alter the ecotone between two communities (Cadenasso et 

al. 1997). Understanding of how ecotonal boundaries influence the 

functioning of ecological systems is poorly developed (Cadenasso et 

al. 2003a, 2003b, 1997).

Natural catastrophic disturbances and intentional-management 

catastrophic disturbances, such as variable-retention timber harvesting, leave and maintain substantial biological legacies for the newly 

reorganizing forest. In Pacific Northwest landscapes under natural 

disturbance regimes or managed on long rotations with an emphasis on intracommunity biocomplexity, occasional patches of earlysuccessional communities may add substantial species diversity to 

the landscape. Variation in species diversity among communities in 

landscapes is due to the structure, composition, and productivity of 

the various biotic communities, unless a community type is rare and 

patches are very small or small and isolated from similar communities—then it might have reduced diversity (Aars and Rolf 1999; 

Bayne and Hobson 1998; Bender et al. 1998; Boulinier et al. 2001; 

Brothers and Spingarn 1992; Debinski and Holt 2000; Lindenmayer et al. 1999, 2002; MacArthur 1965; MacArthur and Wilson 1967; 

McIntyre and Hobbs 1999; Opdam 1991; Robbins 1982; Whitcomb 

1977; Whitcomb et al. 1976; Yahner 1985, 1988; and many others). 
150 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

The effects of island size and distance from the mainland and agricultural-urban woodlot size and distance from other woodlots have 

been shown to reduce diversity and abundance of numerous species 

of various life forms. Island biogeography gave rise to conservation 

biology, which focuses on reserve design (single large versus several 

small reserves), degree of isolation of forest fragments, and the need 

for connecting corridors between fragments of isolated forest. However, one size never fits all; even within the narrow group of mammalian predators within a small region, measurement and mitigation of fragmentation must be scaled to species mobility (Gehring 

and Swihart 2003).

Fragmentation

In recent years, fragmentation has been viewed as the primary threat 

to diversity. Fragmentation routinely is conflated with (1) destruction 

of forests; (2) deliberate change in forest type (e.g., conversion of 

deciduous forest to conifer monocultures); (3) change in seral-stage 

structure of forested landscapes; (4) change in disturbance regimes 

of particular landscapes and regions; (5) direct human disturbance 

of wildlife (such as noise and mechanical impacts of forest management activities), recreational activities (hunting, fishing, birdwatching, hiking, and sightseeing), nature study, and ecological research; 

(6) effects of roads, which range from habitat loss to barriers to 

movement, pollution, and killing of wildlife by vehicles; (7) spread 

of exotic species; and (8) negative effects on soils, hydrology, and 

aquatic systems. It can be useful to distinguish between the effects 

of loss of forests to other uses of the land (loss of total area available 

for habitation by various species and loss of particular types of biotic 

communities) and fragmentation (isolation) of the remaining forest 

suitable for habitation by a species or group of species. Fragmentation refers to those effects of long-term (multiple decades to centuries) isolation of a plant community type or seral stage by markedly 

unlike types; short-term isolation may have no long-lasting effects. 

Long-term isolation includes effects on dispersal processes; small 

population sizes (which result in increased probability of genetic inbreeding, reduced fitness, and extirpation by various causes); effects 

on microclimatic and other physical modifications of isolated patch 

by its matrix; competition, parasitism, and predation by species well 

adapted to the matrix and matrix-patch interface; and aggregations 

of habitat elements of various wide-ranging species at scales mismatched to the species’ life histories. 
C H A P T E R 6 Ecological Foundations of Biodiversity 151

Fragmentation can affect forests in several different ways. For 

example, old-growth remnants can contribute to much of the species diversity in young forests. The amount of old-growth forest in 

an agricultural landscape can account for more than 65 percent of 

the variation in late-seral herb diversity within recently established 

forests (although, it may still take centuries for all herbs to recolonize and come to some equilibrium in species diversity) (Vellend 

2003). In contrast, small remnant patches well separated from one 

another may reduce the ability of a forest to support local vertebrate 

populations. For example, the Oregon white oak communities of the 

Puget Trough of Washington are embedded in a prairie, wetland, 

and second-growth Douglas-fir matrix. Oak patches are dwindling 

in size owing to invasion by Douglas-fir and fire exclusion, and in 

number owing to agricultural, suburban, and urban development. 

The result is the near and perhaps imminent extirpation of the western gray squirrel in western Washington (Bayrakci et al. 2001, Ryan 

and Carey 1995). Fragmentation can also lead to scale mismatch. 

For example, when second-growth Douglas-fir in the competitive 

exclusion stage fragments old-growth Douglas-fir forest, it may 

result in an increase in the total area traversed by spotted owls to 

meet their minimum habitat area requirements at costs substantial 

enough to produce instability in owl pair membership (Carey et al. 

1992). 

Logging of old-growth forests in the Pacific Northwest has reduced markedly the total amount of old growth and produced a distribution of old growth characterized by large blocks, donuts (large 

blocks at mid elevations but with centers at high elevations without 

forest), and scattered small patches embedded in a landscape of 

second-growth forest. Although some scattered patches are small 

enough to suffer climatic influences of adjacent nonforest (shrubsapling stages), the nonforest usually develops quickly into closedcanopy forests, and the remnant patches of old growth retain their 

associated flora and fauna (e.g., Neotropical migratory birds, Carey 

et al. 1991; aquatic amphibians, Bury et al. 1991b; vascular plants, 

fungi, and small mammals, Carey 1995, Carey and Johnson 1995, 

Carey et al. 1999b, Corn and Bury 1991a; and invertebrates, Marcot 

2004). For these organisms, logging old growth led to habitat loss 

and habitat degradation but did not lead to effects of fragmentation, 

although recolonization of logged-over streams by aquatic amphibians did not take place after four to five decades (Bury and Corn 

1991, Corn and Bury 1989), and questions remain about the ability of red tree voles to colonize developing second-growth forests 

(Carey 1999; Corn and Bury 1986, 1988; Gillesberg and Carey 1991). 
152 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

A recent survey revealed little experimental evidence to support the 

contention of fragmentation effects (Debinski and Holt 2000). Only 

20 experiments were uncovered, 6 in forests and 14 in old fields. Arthropods showed the best fit to the theory. Birds, mammals, earlysuccessional plants, long-lived species, and general predators did not 

respond as expected. The reasons for lack of fit to theory were edge 

effects, competitive release, and the spatial scale of the experiment. 

Whereas fragmentation is often stated as deleterious to biological diversity, mosaics are thought to increase diversity. Thus, it is important to distinguish between mosaics and fragmentation. Mosaic 

phenomena belong to two broad subgroups (Whittaker and Levin 

1977):

 Intracommunity patterns related to microsite differentiation 

and species responses to it, such as development of habitat 

breadth or diversity in vegetation site types—microsites are the 

places where plants are rooted, and variation in microsite and 

the species occupying them produces a mosaic differentiated 

both physically and biologically.

 Intercommunity successional and developmental mosaics for 

which disturbance is a major determining force. 

There is almost universal occurrence of mosaics in natural biotic communities. The diversity of these internal mosaics is a consequence of 

the evolution in natural communities toward diversity of both species and interspecies relationships. Disturbance disrupts patterns in 

vegetation communities owing to environmental gradients, producing a mosaic of communities. The disturbance mosaic and the mosaic owing to variation in biotopes (physical landscape elements, or 

places of life; larger physical sites that support biotic communities) 

result in a variety of more or less stable states in the landscape in the 

absence of further disturbance. 

The pervasive notion that the matrix in which forest fragments

are embedded is hostile to organisms within those fragments is 

often, even usually, not the case. A landscape considered structurally fragmented may still be functionally variegated (diversified) to 

some species (McIntyre and Hobbs 1999). Several factors are often 

overlooked when applying principles of island biogeography to oldgrowth forests in forested landscapes: 

 Within such landscapes, the majority of old-growth-associated 

species are found in most seral stages of forest development 

(Ruggiero et al. 1991). 

 Almost all old-growth-associated species will be found in 
C H A P T E R 6 Ecological Foundations of Biodiversity 153

younger forests if those forests have significant biological legacies and intracommunity complexity (Carey 1989; Carey et al. 

1992, 1999b, 1999c). 

 Connectivity in a forested landscape can be achieved by several 

mechanisms besides corridors (including riparian areas) dedicated to spatial connectivity:

 Permeable edges—edges between seral stages that do not 

present barriers to dispersal—also provide spatial connectivity. 

 Maintenance of shifting steady-state mosaics in forests 

managed under long rotations provides temporal connectivity among patches of old-growth/old-complex forests. 

 The earlier the seral stage—the shorter its duration and 

the lower its proportion of the landscape under intentional 

management for biodiversity (Carey et al. 1999c) and the 

greater the likelihood of maintaining old-growth species, 

such as the spotted owl (Carey et al. 1992, Carey and Peeler 

1995) and northern goshawks (Finn et al. 2002) in the landscape.

 Various landscape elements, such as areas with potential for 

deep-seated or rapid-shallow landslides, wetlands, and rock 

outcrops, maintained in intact forest contribute to a finer 

scale mosaic than most operational landscape units, providing refugia for organisms of limited vagility and foraging 

opportunities for organisms of high mobility. 

 Roads provide dispersal corridors, facilitate movement, and 

increase accessibility of different patch types for many native species. 

 High nest parasitism and predation are often associated 

with forest edges in agricultural-urban landscapes. However, 

in forested landscapes, parasitism may be rare in ecotones, 

and predation may be more prevalent in interiors of biotic 

communities than in ecotones (Tewksbury et al. 1998).

Allen and Hoekstra (1990) suggested the useful analogy of biotic communities in a landscape as wave interference patterns between 

processes and organisms interfering with and accommodating each 

other—a more useful, dynamic, concept than specific black-andwhite communities (either habitat or nonhabitat for various species) 

etched into a map of places in the landscape. The main evidence 

for fragmentation effects has been from studies of birds in generally nonforested landscapes. In managed forest landscapes, however, 

a proliferation of songbird fragmentation studies has produced a 
154 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

growing awareness that avian diversity and abundance reflects the 

quantity of the different biotic communities available rather than 

the spatial arrangement or fragmentation of any one of them (Cushman and McGarigal 2003, Lee et al. 2002, Lichstein et al. 2002, 

Lindenmayer et al. 2002). Furthermore, the accumulated research 

does not support the concepts of consolidating clearcutting to reduce edge and landscape heterogeneity. Haila (2002) described the 

concept of island biogeography as an “intellectual attractor” that is 

too ambiguous to be useful in terrestrial environments—all natural environments are fragmented and that different organisms and 

ecological systems experience fragmentation in variable and even 

contradictory ways. Thus, any analysis of fragmentation must be 

context specific given the variety of organisms and multiplicities of 

temporal and spatial scales. In terrestrial systems, it is impossible to 

distinguish between disturbance and fragmentation as conventionally defined; distinguishing between fragmentation and a mosaic is 

a matter of degree and permanence of change in capacity to support 

a complete biotic community.

Isolation, Connectivity, and Viability

Ecologists have focused on number and overall connectivity of 

patches of habitat of particular species or of biotic communities 

supporting assemblages of species as landscape features. Landscape 

details include the size, shape, and edge permeability of the patches 

(Buechner 1989). Much discussion relates to the viability of a species metapopulation in a patchy environment in which local populations are subject to periodic extinction. Viability, under these premises, depends on successful dispersal and colonization of vacated or 

underpopulated patches. Some patches may be dispersal sinks that 

absorb more dispersers than they produce, effectively removing individuals from the metapopulation. 

Four factors influence the movement of animals into sinks: (1) 

the perimeter-area ratio of the source patch, (2) the size of the sink 

relative to the size of the source, (3) the distance that dispersers can 

travel through a sink, and (4) the ease with which individuals move 

across the edges of the source patch. Sinks are only important to the 

degree to which they absorb individuals that may have gone on to 

colonize vacated habitats or individuals that emigrate as a matter 

of life history from an underpopulated patch and subsequently are 

unable to return. A sink can be a valuable source of colonists when it 

is near a source patch, yet does not suffer from the same forces that 
C H A P T E R 6 Ecological Foundations of Biodiversity 155

occasionally bring about extinction of the population in the source 

patch. Sources that routinely produce surplus animals that immigrate may occasionally suffer abrupt extinctions of their own population (or in the case of overdispersed species, such as the spotted 

owl, the death of a member of a breeding pair). Defining landscapes 

simply in terms of sources and sinks is as problematic as defining 

them in terms of habitat and nonhabitat. Few documented cases exist of strict sinks, but many exist of varying quality of habitat. 

Emphasis on patchiness in relation to dispersal and colonization stems from island biogeography (MacArthur and Wilson 

1967). A crucial difference between islands and continental systems 

is the ability of species to move between areas. Island biogeography 

sought an understanding of the species-area relationship and factors 

influencing the relationship (e.g., isolation and island elevation) in 

the context of islands in an inhospitable sea (MacArthur and Wilson 

1967). Confusion often results from application of island concepts 

to forested landscapes (Carey and Harrington 2001). Misapplication of island concepts has contributed to failure to identify factors 

relevant to diversity at particular scales in continental environments, 

especially because scale of isolation differs with species life histories 

(Whittaker et al. 2001). Insularization of terrestrial communities 

occurs when climate change produces isolated mountaintop communities (Brown 1971) or when land use within a landscape changes 

dramatically, for example, returning Neotropical migratory birds encounter increasing fragmented forests as agriculture isolates woodlots in the Midwest (Whitcomb et al. 1977). 

In western Washington, the western gray squirrel once found 

habitat in the Oregon white oak-dominated ecotones between prairies, Douglas-fir forest, and wetlands in landscape mosaics maintained by judicious prescribed burning by indigenous peoples to 

maintain an important source of medicinal plants and carbohydrates 

such as camas root. Gray squirrels require more than 5 hectares of 

juxtaposed oak woodland, Douglas-fir forest, and wetlands for habitation (Ryan and Carey 1995); a minimum effective population size 

in this environment would certainly require more than 50 occupied 

sites within a small landscape for genetic reasons alone (Soulé and 

Wilcox 1980). In the last century, fire suppression and fire exclusion have led to invasion and dominance of the oak woodlandprairie-wetland mosaic by Douglas-fir (Thysell and Carey 2001b). 

Reduced frequency of occurrence, size, and vigor of oak woodlands 

and motor vehicle traffic along roads near the remaining woodlands 

now threatens the continued existence of populations of western 

gray squirrels in western Washington (Ryan and Carey 1995). Even 
156 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

though a substantial area of oak woodlands and oak-fir ecotones 

remain, they are widely scattered across a landscape dominated by 

Douglas-fir forest, prairies, and human development. Western gray 

squirrel populations have crashed (Bayrakci et al. 2001). Although 

underconnected landscape elements can produce problems in dispersal, colonization, and maintenance of viable populations, excessive connectivity between individual organisms and homogeneity of 

communities can lead to increased susceptibility to density-dependent catastrophic disturbances, such as disease.

Temporary Isolation

In the western Washington lowlands, isolation by glaciation, postglacial hydrologic events, maintenance of landscape mosaics by 

indigenes, agriculture, forestry, development of transportation networks, and urbanization resulted in genetically distinct populations of northern flying squirrels in the Black Hills and the Puget 

Trough lowlands (Wilson 1999b). Timber harvest within the lowlands reduced genetic variability in local populations in the short 

term, but genetic diversity recovered rapidly because of outbreeding 

with nearby local populations. The flying squirrel is remarkably well 

adapted to avoiding inbreeding with its promiscuous mating system and long (relative to body size and population density)-distance 

movements (1 to 5 kilometers) by males to find mates. Multiple 

paternities of single litters have been documented (Wilson 1999b). 

Similarly, in Finland, the Siberian flying squirrel is threatened by 

past land use changes but now benefits from improved landscape 

permeability afforded by second-growth forest of low-quality habitat (Reunanen et al. 2000). 

Conclusions on fragmentation in other studies of small mammals in the Pacific Northwest are debatable (Carey and Harrington 

2001). Studies of Keen’s mouse isolated in old-growth forests separated by clearcuts raised concern about effects of fragmentation 

(Lomolino and Perault 2000). Other studies found California redbacked voles isolated in old growth by clearcuts (Mills 1995). Both 

concluded there were negative effects of forest fragmentation and 

called for systems of reserves and corridors. Keen’s mouse, however, 

is common in forests 40 to 90 years old with a western hemlock component (Carey and Harrington 2001, Carey and Johnson 1995, West 

1991) and California red-backed voles also are common in young 

forests (Corn and Bury 1991a, Gilbert and Allwine 1991) (table 11). If 

isolated by clearcuts, isolation would be relatively short lived. Thus, 
Table 11—Relative abundances (percentage of value in old growth) 

of the western red-backed vole in young, mature, and old-growth 

forests in the Oregon western Cascades and Coast Range 

Seral stage

Province Young Mature Old growth

West Cascades 85 71 100

Coast Range 67 111 100

Source: Adapted from Corn and Bury 1991a and Gilbert and Allwine 

1991.

C H A P T E R 6 Ecological Foundations of Biodiversity 157

temporal landscape dynamics, such as shifting steady-state mosaics 

maintained by regulated forests, are important considerations but 

rarely considered in landscape-scale studies of the effects of forest 

management on vertebrates.

Dispersal and Colonization

“Opportunities for movement and habitat diversification provided 

by the spatial aspect of the environment make possible in a variety of 

ways coexistence of species that could not otherwise survive together” 

(Levin 1976). Furthermore, if a landscape is heterogeneous, different 

combinations of species are likely to be favored in various locations 

and maintained elsewhere principally by dispersal from more favored 

regions, and this will act to increase the overall species richness. Dispersal in heterogeneous environments serves to lessen fluctuations 

in species populations and may increase population persistence by 

several orders of magnitude (Roff 1974a, 1974b). Dispersal is also 

important in colonization of newly developed regeneration niches. 

For example, Schwarz et al. (2003) found that, for seven species of 

trees at Hubbard Brook Forest in New Hampshire, environmental 

factors, disturbance, and competition operated within the local patch, 

but spatial autocorrelation suggested that neighboring patches were 

important as sources of colonizers consistent with seed-dispersal 

distance. Elevation was the primary environmental factor, followed 

by slope angle, and soil chemistry. In Amazonian forests, spatial heterogeneity plays an important role in the coexistence of Neotropical 

ant species that feed on the same species of plant. Where the food 

plants are found in high densities, the more fecund species dominate. 

Where the food plants are well distributed, the species that is the 

better long-distance flier dominates. A dispersal-fecundity tradeoff 

allows two genera to treat spatial heterogeneity in patch density as 
158 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

a niche axis, and heterogeneity allows coexistence of the ants in the 

landscape (Yu et al. 2001). 

Movement of organisms through landscapes depends on how 

they move and their capacity for movement. The wind-dispersed 

seeds of some plants and the spores of some fungi move long distances through and above the vegetation. The seeds of other plants, 

the spores of hypogeous fungi, and propagules of lichen move little 

or depend on dispersal by animals. Invertebrates exhibit huge variety 

in mechanisms and range in movement, moving from centimeters to 

kilometers. Migrating birds, waterfowl, many raptors, and bats move 

across the landscape in the air, well above the vegetation, little influenced by the nature of the biotic communities below, other than the 

contribution of the communities to the quality of the landscape as 

migratory corridor or as a habitat (an arrangement of patches suitable for foraging, roosting, nesting, and other essential behaviors). 

Other birds, in their daily activity, may confine their movements 

to particular strata of vegetation or show various degrees of willingness to move between landscape elements of markedly different 

natures. Terrestrial amphibians, reptiles, and some small mammals 

move through litter on the ground for relatively short distances of 

less than 5 to 50 meters on a daily basis (e.g., shrews and some salamanders) but farther when dispersing. Other mammals move on the 

surface of the forest floor from 50 to 500 meters daily (e.g., mice and 

chipmunks) to more than 1 kilometer (deer and elk). Squirrels (from 

the family Sciuridae) move daily from 100 meters to more than 1

kilometer through forest canopies (Carey 1991, 2000a). 

Characteristics of the landscape that influence animal movement include environmental grain (the size of the patches within 

biotic communities and landscapes), sharpness of edges, nature of 

boundaries, connectivity, and interface permeability. Success of transit among landscape elements depends on the relative habitat quality of the various landscape elements (Basquill and Bondrup-Nielsen 

1999). Adjacent elements each with high quality as habitat present 

few barriers to movement; the boundaries, edges, and ecotones between them have high permeability. Permeability can be measured 

by a species’ willingness to cross the boundary. Permeability is also 

influenced by (1) motive to move, (2) the characteristics of the habitat of origin, (3) the characteristics of the patch of destination, and 

(4) the characteristics of the ecotone. A dispersing animal may be 

more willing to cross an unfamiliar or inhospitable environment 

than a foraging animal. An animal leaving a saturated or poor-quality habitat may move more willingly into a less populated or higher 

quality habitat. 
C H A P T E R 6 Ecological Foundations of Biodiversity 159

Figure 26—A western tanager is a 

common spring and summer visitor to 

the Pacific Northwest. Photo courtesy 

of USDA Forest Service.

Habitat selection itself is density dependent (Greene and Stamps 

2001). Animals generally adapted to exploiting forests, for example, 

Neotropical migratory birds (fig. 26), may show minor effects on 

abundance but not distribution, in landscapes dominated by forests 

over 40 years old, even if the oldest forests are isolated by younger 

forests in the landscape. In other words, young forests are slightly 

poorer quality habitat for Neotropical migrants and markedly poorer for year-round resident birds, but both groups persist in the young 

growth, and their abundances are unaffected in the old forest (Carey 

et al. 1991, Haveri and Carey 2000). In Quebec landscapes where 

forests were fragmented by agriculture and urbanization, nonmigratory movements of breeding Neotropical migratory birds were 

affected by landscape composition and configuration. Other effects 

of fragmentation beyond habitat loss and limitation of movements 

among patches of habitat may include nest parasitism and predation 

(Belisle et al. 2001), especially in nonforested landscapes. 

Linear features of the landscape, such as trails, roads, roadsides, 

fencerows, streams, and poorly vegetated ridgetops may variously 

facilitate or impede movement depending on the species. Roads and 

roadsides provide corridors for dispersal and enable gene flow in 

small mammals in fragmented forests in Australia (Bennett 1990). 

However, it can be difficult to distinguish a travel corridor from a 

linear habitat. For example, white-footed mice in the United States 

prefer structurally complex fencerows over their natural habitats 

of intermediate to simple structure (Merriam and Lanoue 1990). 
160 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Passerine birds in Poland used shrub corridors to make greater use 

of a pine-meadow-lake mosaic than a mosaic without shrub corridors (Dmowski and Kozakiewicz 1990). Simulation models suggest that any corridor is better than none, high-quality corridors can 

increase metapopulation size, and populations in isolated patches of 

habitat, even if connected by low-quality corridors, are most vulnerable to extinction (Henein and Merriam 1990). In Great Britain, the 

European red squirrel has an effective dispersal distance of less than 

1.5 kilometers between patches of forest separated by fields. Deforestation resulted in genetic isolation. Corridors that linked patches 

of forest and patches that were less than 1.5 kilometers apart allowed 

the squirrels to disperse by using patches as stepping stones. Limited 

reforestation allowed northern genes to leapfrog through hundreds 

of forest fragments and hundreds of kilometers in 20 years (Hale et 

al. 2001). This increased connectivity in the landscape, however, is 

raising fears of epidemic spread of the parapox virus that is deadly to 

squirrels. In Italy, extensive forest and forested corridors are allowing 

the spread of introduced eastern gray squirrels, which are threatening the continued existence of the native European red squirrel; the 

fear is that forested corridors will lead the eastern gray squirrel to 

France (Lurz et al. 2001).

Landscape Epidemiology

Concerns about settlers contracting zoonotic diseases (diseases of 

wild animals transmissible to people) in the former Soviet Union 

led to the development of landscape epidemiology (Pavlovsky 1966), 

a long-forgotten precursor to today’s landscape ecology that evolved 

primarily from island biogeography (MacArthur and Wilson 1967). 

Pavlovsky died at the age of 81 in 1965. He developed his theory 

of the natural nidality (sensu site, nest, or niche) of pathogen persistence in 1939. Pavlovsky showed that the presence of organisms 

pathogenic to humans or their domestic animals could be predicted 

from the characteristics of the landscape. Investigation of the landscape-biotic community-pathogen complex relationship could be 

used to identify modifications of the landscape to break the transmission of pathogens among wild animals or changes in human use 

of the landscape that would reduce the risk of exposure of people 

and domestic animals to the pathogens. Pavlovsky implemented 

successful landscape management programs by using a hierarchical approach starting with biogeographic regions and scaling down 

to landscapes and biotic communities within landscapes. Efficacy 
C H A P T E R 6 Ecological Foundations of Biodiversity 161

entailed understanding the community ecology of the pathogen as 

well as the autecologies of the hosts and vectors of the pathogen. In 

the United States, landscape epidemiology has been used in research 

on rabies ecology and control in the Mid-Atlantic States (Carey 

1982, 1985a; Carey et al. 1978), the ecology of Colorado tick fever in 

Rocky Mountain National Park in Colorado (Carey 1978c, Carey et 

al. 1980b, McLean et al. 1993), and Lyme disease in New England 

(Carey et al. 1980a, 1981). Studies of host-parasite systems, more 

than perhaps any other systems, mandate a consideration of variety in spatial scale—from landscapes of tissues within an organism 

(Carey and McLean 1978) to landscapes of biotic communities that 

support the parasite, vector, and hosts (Carey 1979; Carey et al. 1978, 

1980b) and to regional (Carey 1982) and global (Carey and McLean 

1983) variations in the ecology of a pathogenic organism. Epidemiology also reinforces the idea of being careful about what one 

wishes for—Hunter (1999) stated the goal of conservation biology 

was to preserve all species down to the lowest microbe; many would 

disagree with the values (and outcomes) implicit in that goal.

Landscape-epidemiological approaches incorporating spatial 

analysis in nested hierarchies of scale are now providing better understanding of diseases and parasites of wild plants, including trees. 

In Arizona, mistletoes that infect mesquite trees are spread by the 

Phainopepla, a bird that consumes its fruits and defecates its seeds. 

The pattern of infections and spread, however, is influenced by different factors at different scales (within tree, within the neighborhood 

of the tree, and across the landscape) that reflect interactions of the 

three species and the external environment (Aukema 2003b). Many 

diseases of trees are influenced by the structure and composition 

of biotic communities and landscapes. Basic epidemiology predicts 

that large numbers of susceptible hosts in contact with one another 

invite an epidemic—the larger the numbers, the greater the spatial 

extent of dense populations of susceptible individuals, and the greater the adjacencies of similar populations, the greater the epidemic 

catastrophe. For example, root diseases are important natural disturbance agents affecting all tree species in all forest ecosystems in 

eastern Oregon and Washington (Thies 2001). Shifts in tree species 

composition following fire exclusion (to species vulnerable to root 

rot), partial cutting, and management that retained high densities of 

trees have led to increased root disease. In fact, fire exclusion, introduced diseases, and management that produced high tree densities 

have led to a widespread decline in forest health (Tiedemann et al. 

2000). Dense monocultures of variants ill-adapted to environmental conditions (offsite plantings) are well-known for their low vigor 
162 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

and susceptibility to needle diseases (Kavanagh et al. 2000) and root 

diseases (Filip 1999). The emergence of Swiss needle cast as a serious problem in coastal Douglas-fir illustrates these basic principles 

of epidemiology (Filip et al. 2000). Defoliating insects can produce 

major disturbances; these include spruce budworm, Douglas-fir tussock moth, Pandora moth, and larch casebearer, and others, maybe 

two dozen species overall (Torgersen 2001). Risks of outbreaks of 

these insects increase with low tree species diversity and high densities of susceptible trees.

It is also well known that introduction of novel diseases and 

insect pests can produce catastrophes; for example, chestnut blight, 

white pine blister rust, and numerous others. These introduced diseases may have surprisingly widespread effects even in the absence 

of dense, spatially extensive populations of susceptible individuals. 

For example, a disease complex is causing a decline in Pacific madrone. The primary pathogen is Nattrassia mangiferae, which causes 

cankers and shoot blight. Infected trees are stressed and become 

vulnerable to Fusicoccum aesculi, the secondary pathogen that causes 

branch dieback. All ages and all sizes of madrone are affected (interestingly, the complex can also cause skin disease in people and 

other animals). The primary pathogen was probably introduced into 

California with Persian walnut trees in the 1960s. The low resistance 

of madrone, severe weather stressing madrones, and fire suppression (fire destroys the disease inoculum) have allowed the disease 

to spread rapidly despite the scattered, patchy nature of madrone 

distribution (Elliott et al. 2002). Houston (1992) explicated a simple 

model for dieback and decline diseases: 

Healthy trees + Stress = Altered tree tissues  Dieback

Altered tree tissues + More stress = Further alteration of tree tissues 

 Continued dieback. 

A more complex theory emphasizes S, E, P, and B:

 S—simplified forest structure creates a predisposition to dieback; 

 E—edaphically extensive sites to which the species is not welladapted, including shallow soils poorly buffered from climatic 

extremes, increases probability of stress; 

 P—periodically recurring perturbations owing to weather and 

climate instability produce stress; and 

 B—biotic agents provide the coup de grace (Mueller-Dombois 

1992).
C H A P T E R 6 Ecological Foundations of Biodiversity 163

Interactions between diseases, insect outbreaks, and other disturbances are widely recognized (Bebi et al. 2003, Hayes and Daterman 2001). For example, the White River National Forest had 

widespread fires in 1879 and a spruce beetle outbreak in the 1940s. 

Forests that burned in 1879 were less affected by the beetle outbreak 

in the 1940s. However, neighboring stands dominated by Engelmann spruce and elevation influenced the susceptibility of forests to 

insect infestation. Forests affected by the beetles showed no higher 

susceptibility to subsequent fire. The authors concluded that large, 

infrequent disturbances (fire, beetles) are often the dominant factors 

structuring an ecosystem and produce lasting ecological legacies. 

Subsequent ecological processes are strongly influenced by climatic 

and topographic factors and the contingencies of spatial arrangement of survivors, timing of availability of propagules, and barriers 

to spread of disturbance.

Landscape Mosaics

Mosaics can be variously hostile to biodiversity, supportive of biodiversity, inimical to particular species, or scaled such that they are 

supportive of all the indigenous flora and fauna. When landscapes 

are degraded by disturbances or lack of disturbances (natural or 

anthropogenic), effects of insularization owing to habitat loss are 

rarely distinguishable from direct effects of habitat loss or degradation without consideration of a variety of life-history characteristics 

of the organisms of interest. Spotted owls in the Western Hemlock 

Zone of southwestern Oregon occupied increasingly large areas as 

old-growth forests were harvested and replaced by early-seral stages 

(Carey et al. 1990). Eventually, owls were no longer able to track their 

prey base and their social structure began to break down (Carey et al. 

1992). Although owls foraged in forests other than old growth, these 

foraging areas were either widely scattered or only intermittently 

suitable for foraging (Carey and Peeler 1995). In the Mixed Conifer 

Zone, more varied prey with a greater total biomass allowed owls to 

occupy smaller ranges and to use less old forest than in the Western 

Hemlock Zone just to the North. Isolation of blocks of old forest by 

intervening large clearcuts, however, was equivalent to the loss of an 

entire prey species in terms of energy expended to access sufficient 

amounts of old forest (Carey and Peeler 1995). Nevertheless, the 

grain (scale of patches) in the landscapes was small enough that dispersal and recolonization processes remained successful. Thus, the 

effects of timber harvesting on spotted owls were habitat loss and 
164 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

degradation of the landscape as a whole as a context for spotted owl 

habitat. It is not clear if there were negative effects owing to insularization. Spotted owls foraged in isolated patches. There was no 

evidence of either impediments to recolonization of vacated habitat 

or genetic isolation, either by barriers to movement or isolation by 

distance. Long-term genetic effects would be unlikely, given current population sizes and landscapes gradually improving in habitat 

quality. Markedly reduced metapopulation size and reduced reproductive attainment owing to pair instability, however, increases the 

probability of local extinctions that, theoretically, could cascade into 

regional extinctions.

As with spotted owls, landscape use greatly affects Tengmalm’s 

owl in Finland, a small woodland owl that preys on voles whose 

abundance varies over 3- to 4-year cycles (Korpimaki 1988). Agricultural lands are its preferred foraging areas when voles are numerous. Spruce forest is preferred when voles are low in abundance on 

agricultural lands. Pine plantations are avoided. Of 104 territories 

studied for 10 years, more were occupied in only 1 year or in 5 or 

more years than would be expected by chance. Twenty-nine areas 

of the landscape were never occupied. Owls in good territories benefited from vole peaks by foraging over farmlands and shifting to 

alternate prey in woodlands during the low phase of the vole cycle. 

These more structurally complex portions of the landscape provided 

opportunities for prey switching. Poor territories supported breeding pairs only in peak vole years. Nearly all females shifted territories between successive breeding attempts, moving to more experienced males who could track local prey populations, rather than just 

moving to territories in better structured portions of the landscape. 

Males did not change territories.

Because predators are especially challenged by variable landscapes, theoretical ecologists have begun to model the dynamics of 

predators in patchy environments. They have developed models of 

predator distribution based on relative prey abundance (Bernstein et 

al. 1991). These models assume intake rate maximization, predator 

learning, nonnegligible prey handling time, and mutual interference 

between predators. Independent variables include travel costs between patches and the structure of the environment. When travel 

costs are small, prey depletion is slow, interference is moderate, 

predators conform to an ideal free distribution, and prey mortality 

is density dependent. As travel costs increase, the rate-maximization predator becomes more sedentary, and the population settles 

out at distributions far from the ideal free distribution. Prey mortality approaches density independence and later negative density 
C H A P T E R 6 Ecological Foundations of Biodiversity 165

dependence. In semicontinuous environments, with prey density 

correlated between neighboring patches, the slower the rate of spatial variation in prey (i.e., the coarser the environmental grain), the 

poorer the adjustment to the ideal free distribution, on account of 

the predator’s need for learning. When the sample of the landscape 

within the reach of the individual predator is unrepresentative of the 

average prey density in the landscape (grain is coarse relative to the 

range of the predator), predators cannot learn the global distribution 

of foraging opportunities and fail to optimize intake. Predators shift 

ranges whenever the gain rate in the current patch is lower than 

the expected mean gain rate for the landscape as a whole. Well-informed predators should treat the world as though it were discontinuous (patchy) by aggregating only in patches with prey density 

above a certain threshold. As the cost of shifting foraging areas goes 

up, it still pays predators in very poor patches to move. Nevertheless, for patches above a certain threshold, cost of migration offsets potential gains of moving and predators do not migrate. Above 

that threshold, predators are distributed at random across patches 

with inverse density dependence between intermediate and good 

patches. If the cost of migration is very high, predators do not move 

even from poor patches, and predator mortality becomes inversely 

density-dependent across patches. These model simulations do not 

address, but do illustrate, that patch quality defined in terms of absolute prey abundance is of paramount importance in maintaining 

healthy predator populations even though relative differences between patch types may remain high (Carey and Peeler 1995).

Southwestern Oregon has suffered some of the most severe effects of timber harvesting on landscape composition in the Pacific 

Northwest (Carey et al. 1992, Carey and Peeler 1995). Patches of 

old-growth forest often were isolated from one another, with intervening expanses of early seral stages. However, studies of terrestrial 

amphibians (Corn and Bury 1991b), forest birds (Carey et al. 1991), 

and small mammal communities (Corn and Bury 1991a) revealed no 

fragmentation effects. Similarly, salamanders occupied even small 

patches of old growth in coastal British Columbia, suggesting such 

patches retain value as habitat (Dupuis and Bunnell 1999). Species 

of terrestrial salamanders in southwestern Washington respond differently to timber harvests but generally remain present in stands 

after thinning (Grialou et al. 2000). The reasons for lack of fragmentation effects are two: few species have distributions confined 

to old growth (Carey 1989), and forests develop rapidly after timber harvests, thus the duration of absolute isolation is too short for 

untoward genetic effects or stochastic demographic processes that 
166 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 27—A cascading watercourse through a basalt streambed. 

Photo by A. Carey. 

may lead to extinction. The effects of continued isolation of oldgrowth fragments by clearcuts and competitive exclusion stages 

are unknown but would be expected to have negative impacts on a 

number of species, especially some of those that are poor dispersers and that have low reproductive potential (Carey 1989). Aquatic 

amphibians do show effects of isolation. Timber harvesting across 

small water courses in southwestern Oregon evidently led to extinction of local populations; these sites remained uncolonized decades 

later (Bury et al. 1991b, Corn and Bury 1989). The reasons for lack of 

colonization, however, are unclear—Did the streams remain unsuitable for habitation? Were there no nearby (relative to ability) sources 

of colonizers? Was the forest surrounding the streams inhospitable 

to dispersers (of low permeability)? Were the streams below the 

reaches studied even less hospitable (less permeable to dispersers) 

than the reaches themselves?

Landform Variability

Landform sets the stage for the ecological theatre—the diversity 

of biotic communities in a landscape—and the evolutionary play 

(Hutchinson 1965). Variability in landform includes differences in 

elevation, aspect, slope, and lithology, for example, basalt versus marine sediments. These factors influence many other environmental 

variables, such as solar radiation (including photosynthetically active radiation), temperature regime, wind, precipitation, soil moisture, substrate texture, mass soil movements, and erosion, on a finer 

scale than the influence of overall climate. Topography and geology locally, as well as regionally, determine degree of dissection by 

watercourses, presence of wetlands, cliffs, rock outcrops, and talus, 

soil-site characteristics, and abundance of fine sediments in streams. 

Together, these determine the types of, and variation in, potential 

natural vegetation and availability of niches of highly specialized 

animals. For example, a substrate of marine sediments is more easily 

eroded than one of basalt (fig. 27). Streams running through marine 

sediments or glacial outwash are more likely to have large woody debris incorporated in their structure, and pools formed by large woody 

debris are likely to accumulate sediments (figs. 28A, C) following 

large upstream disturbances, reducing interstices between rocks that 

are important to larval giant salamanders; these streams are also less 

likely to have the smooth rocks needed by tailed frogs (Wilkins and 

Peterson 2000). Still, these streams may provide reaches suitable for 

spawning by Pacific salmon (fig. 28B). 
A C

B

C H A P T E R 6 Ecological Foundations of Biodiversity 167

Figure 28—(A) and (B) coarse 

woody debris creates pools along a 

stream; (C) sediment deposition along 

a stream favored by chum salmon 

(note the dead chum salmon). Photos 

by A. Carey.

Natural disturbance history, anthropogenic disturbances such 

as accidental fire, purposeful fire, grazing, timber management, and 

zoning (transportation corridors, cities, towns, suburbs, agricultural 

lands, rangelands, managed forests, parks, natural areas, and wilderness) determine the actual diversity within, and particular nature of, 

biotic communities in the landscape. The interplay between landscape character and biodiversity has led to the conclusion that environmental variation would be a good surrogate for directly measuring organismal diversity (Faith and Walker 1996). For example, 

in western Washington, Bosakowski (1997) found more bird species (78 species) in a landscape managed as an industrial forest than 

Manuwal and Huff (1987) found in natural forests more than 40 to 

500 years old (46 species). This, however, is a comparison of apples 

and oranges—a sample of a landscape with all its inherent variability compared with a sample of narrowly defined forest conditions. 

The landscape still lacked species dependent on old growth, the seral 

stage that was in shortest supply. This example does illustrate problems inherent in reducing measurement of biodiversity to a single 
168 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

(or a few) indexes—too much information is lost; effects of variability at different scales and effects of variability within types are 

lumped into coarse categories of landscape units (either physical or 

biotic, usually not both); information on entire ecosystems and species groups is lost, including effects of isolation on particular types 

of landscape units.

Landform Analysis, Communities, Habitats, and Niches

The ecosystem concept and ecosystem management have been challenged on the basis that ecosystems cannot be precisely defined and 

that ecosystem size differs with the size of the organism, life form, or 

process of interest. This challenge is only defensible for strict, narrow 

views of the world. Definition of ecosystems and scales of ecosystem 

management must include, of course, an appreciation of the various 

spatial scales at which various organisms operate—from viruses to 

spotted owls (Carey and Curtis 1996; Carey et al. 1978, 1980a, 1980b, 

1992, 1999b). A hierarchy of scales is also necessary. Landscape analysis allows scaling of variation in geomorphic features and of the 

biotic communities that result from the interaction of landform and 

historical and contemporary disturbance regimes. Scaling is commonly used in watershed analyses, supported by systems ecologists 

(Odum 1971), community ecologists (Whittaker et al. 1973), population biologists (Hutchinson 1978), landscape ecologists (O’Neill et 

al. 1986), and empirical data from the Pacific Northwest (Carey and 

Peeler 1995). Scaling is essential to ecosystem and landscape analysis 

and management. Scaling can be related to various life forms and 

life histories. 

A useful hierarchy begins with units homogeneous in aspect, 

slope, slope position, elevation, soil, geomorphology, rainfall zone, 

and other characteristics that make up landscapes and are the places 

where plants and animals settle. These are biotopes—places of life

(Hutchinson 1978) and can be described in terms of their potential 

natural vegetation. For example, Henderson et al. (1989) mapped 

the 64 forested plant associations of the Olympic National Forest 

on this basis. Note that Hutchinson (1978) describes biotopes as 

being homogeneously diverse—in other words, they can be broken 

down into successively more homogeneous subparts and scaled up 

into larger units that may also be homogeneously diverse such as a 

shifting, steady-state, mosaic landscape. Yet, in the rugged topography of the Pacific Northwest, a natural ecological scaling, which is 

also operationally appropriate, presents itself with the variation in 
Biotope

A landscape: made up of biotypes, containing communities

C H A P T E R 6 Ecological Foundations of Biodiversity 169

Figure 29—A schema for precise 

terminology—a landscape is made 

up of relatively homogeneous units 

of landform. These units are biotopes, 

or “places of life.” Biotopes illustrated 

here are a wetland, a lowland, a toe 

of a slope, and a mid-slope. Biotopes 

are occupied by biotic communities, 

which are often characterized by their 

dominant vegetation and seral stage. 

This landscape is composed of forest 

communities that differ in species 

composition and seral stage. The range 

of biotic communities a species can 

inhabit is called its habitat. Quality 

of habitat can be inferred by plotting 

the density of the species across the 

array of biotic communities. Thus, 

habitat is defined by each species’ use. 

Only part of each biotic community 

may be suitable to a species because of 

specific environmental requirements 

or because of interactions with other 

species. The part of the community 

used by species is called a niche. The 

niche is determined by both the ability 

of a species to exploit the resources in 

the community and other species that 

might compete for those resources, 

prey upon the species, or parasitize the 

species. Both habitats and niches can 

be described by multiple environmental variables. These variables describe 

potential habitat and niches (the complete multivariate space available) and 

realized habitats and niches (the space 

actually used) (adapted from Carey 

1981, Whittaker et al. 1973). These concepts are of paramount importance in 

modeling landscapes and in landscape 

management. Few species are confined 

to a single biotic community, and species interactions may be influenced by 

the overall character of the landscape 

or just by adjacent communities that 

differ in species composition.

landform (Carey and Peeler 1995); the task may be more difficult in 

a Midwestern prairie or a lowland tropical rain forest. The species 

occupying and invading the biotope interact to form biotic communities that together with the physical aspects of the biotope are 

ecosystems (fig. 29). Because biotope has received poor acceptance in 

the lexicon of North American ecology, hereafter, landscape unit is 

used interchangeably with biotope, depending on context. 

The ecosystem is the basic functional unit of ecology (Begon 

et al. 1986; Hutchinson 1978; Odum 1963, 1971; O’Neill et al. 1986; 

Whittaker et al. 1973) and is defined as “an ecological community 

together with its environment, functioning as a unit” (Pickett 2000). 

Odum (1971) used small forests (e.g., on a hillside) as examples of 

ecosystems; Bormann and Likens (1979) defined them as small, 

“watertight” watersheds of 10 to 50 hectares. This scale seems appropriate for Pacific Northwest terrestrial biotic communities as well 

(Carey and Peeler 1995, Carey et al. 1999d). However, Odum (1971) 

pointed out that aquatic systems must be defined at a larger scale, 

such as a drainage basin. A tenfold larger scale (100 to 500 hectares) seems appropriate for smaller streams and rivers. Watersheds 

in the Pacific Northwest run in the thousands of hectares (say 5,000 

to 20,000 hectares for state of Washington designated Watershed 

Administrative Units). In reality, three attributes are important in 

defining landscape units: structure (the spatial relationships among 

the distinctive ecosystems composing the landscape), function (interactions among the ecosystems), and change (the alteration of 

the structure and function of the ecological mosaic through time) 

(Turner 1989). Landscapes are aggregations of ecosystems. Each 
170 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

successive level of aggregation can be considered a building block 

for serving larger ecological functions and larger conservation goals. 

The ecosystem is the fundamental building block but cannot be understood or effectively managed without considering intracommunity heterogeneity and landscape and regional contexts. Landscapes 

sum into physiographic provinces that have characteristic vegetation 

zones or life zones and eventually into biomes and, finally, the biosphere.

The basic operational unit in forestry is the stand—a more or 

less homogeneous group of trees. Stand identification rests on the 

age and species composition of the dominant trees and, as a result, 

can vary markedly from less than 5 hectares to thousands of hectares. 

Thus, stands may be perceived as having greater homogeneity than 

their associated biotic communities. Thus, using traditional forestry 

criteria may result in an excessively coarse scale for identification 

and delineation of ecosystems. Traditionally, botany has focused on 

a very small scale—much less than 0.5 hectare. Miller et al. (2002) 

examined spatial patterning of ground-layer species in old-growth 

northern hardwood forests by using 0.25-square-meter plots in 

grids of 1,860-square-meter grids. Ground-layer species were autocorrelated (clumped) at less than 2.5 to 21 meters depending on 

tree sapling density—randomly distributed at high sapling densities 

but clumped at low densities. The smallest scale autocorrelations resulted from vegetative reproduction and larger scale patterns from 

dispersal within a patchy environment. Microtopography and coarse 

woody debris were important to the maintenance of plant diversity within the biotic community, and the authors emphasized the 

need for within-community microhabitats or patchiness, suggesting 

a much larger scale would be relevant to plant communities. Busing 

and White (1993) looked at the effects of area on old-growth eastern 

hemlock-hardwood forest attributes by using 0.1-hectare subplots 

within 1.0-hectare plots. They found canopy gaps were generally less 

than 0.05 hectares, but that tree density, basal area, mass, leaf mass, 

and large tree density suggested a grain or patch size of about 0.2

hectare (one tree occupying 0.05 hectare). Canopy openings covered 

13 percent of the area with most less than 200 square meters, but a 

multiple tree fall gap was more than 1000 square meters. Beckage 

and Clark (2003) also found that spatial heterogeneity in deciduous 

forests was important in providing unique regeneration niches that 

maintained a diversity of trees; York et al. (2003) found the same in 

Sierra Nevada conifer forests with experimental gaps of 0.1 to 1.0

hectare. However, the size, intensity, and spatial distribution of compositional patches were not affected solely by gap size but also by 
C H A P T E R 6 Ecological Foundations of Biodiversity 171

microtopography, seed dispersal distances, vegetative reproduction, 

and species interactions. Their results suggest a scale much larger 

than 1 hectare would be appropriate, especially because within-community heterogeneity is so important. As Kint et al. (2003) concluded, tree distribution and patterning (“positioning”) determines 

different light regimes and regeneration patterns; the mixture of tree 

species also helps to determine light regimes and litter composition 

as well; and vertical and horizontal differentiation resulting from 

positioning, mixtures of tree species, age distributions, and competition determines spatial variation in microclimate, food supply, 

and structural complexity that provides for a variety of animals and 

plants. So, studies of forest plants suggest that communities range in 

size from tens to hundreds of hectares or more but have substantial 

heterogeneity at the scale of 0.2 to 0.5 hectare or less. This is very 

similar to the scale of variation in tree canopies, understory vascular 

plants, fungi, and use of patches by arboreal rodents in old-growth 

conifer forests in southwestern Oregon (Carey et al. 1999b).

Well, what about animals? Morris (1987) examined the question of scale in relationship to individual animals and populations. 

He suggested that both individuals and populations respond in one 

of two general ways. “Fine-grained species” [actually species responsive to fine environmental grain] use subsets of the mosaics within biotic communities in direct proportion to the abundance of the 

subsets; coarse-grained species select some communities over others. The possible scales that could be considered include the species’ geographic range, the spatial scale at which population density 

varies, temporal scales of generation time, migration and dispersal 

distances, territory or home-range sizes, and the space and time of 

daily activities. He suggests distinguishing between two aspects of 

habitat. Macrohabitat would be the minimum area corresponding 

to that within which an average individual performs all of its biological functions during typical activity cycle (essentially the original definition of home range). Microhabitat would be defined by 

the physiochemical variables that influence allocation of time and 

energy within the macrohabitat/home range. This approach, however, is excessively individual-of-species specific; considering the 

responses of species populations is much more informative (Maguire 1973). Describing habitat in terms of the range of biotic communities used, the relative value of those communities as measured 

by some population response, the necessity for specific habitat elements, and the role of within-community heterogeneity in promoting coexistence of species, is much more informative for species 

adapted to fine-grained mosaics (biotic communities) and species 
172 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

responsive to coarse-grained landscapes. Using a population approach will help converge on a common scale related to the natural scale of biotic communities and will result in much smaller units 

than forestry criteria, say covering 10 to 200 hectares. This is also 

the mappable scale of aspect (the direction a hillside faces) in topographically well-dissected, mountainous landscapes (Carey and 

Peeler 1995). Biotic communities of this size are just large enough 

to support populations of vertebrates of low mobility: terrestrial and 

aquatic salamanders (Bury and Corn 1988a, 1988b; Bury et al. 1991a, 

1991b); passerine birds (Carey et al. 1991, Huff et al. 1989, Huff and 

Raley 1991); forest-floor small mammals (Carey and Johnson 1995); 

and arboreal rodents (Carey 1991, 1995). This scale is amenable to 

examining niche complementarity and its effect on ecosystem function and source-sink dynamics for many species (Bond and Chase 

2002). However, a small area (less than 10 hectares) may not withstand the climatic and biologic influences of an adjacent ecological 

community of markedly different character (Chen et al. 1992). Indeed, no ecosystem stands alone—all are influenced by, and receive 

organisms from, the other ecosystems in the landscape. A 10-hectare area is too small to support even an individual spotted owl; a 

spotted owl might forage over 140 hectares in a night (Carey 1993; 

Carey et al. 1990, 1992). Much larger areas may be too small to contain an aquatic ecosystem large enough to support a fish community (Odum 1971). Thus, 10- to 200-hectare biotopes along with the 

plant, fungal, and animal communities they support and the water and energy they receive are good fundamental terrestrial building blocks. This scale is appropriate for examination of biodiversity 

and ecosystem function. At this scale, management can be used to 

set back, maintain, or accelerate the process of forest development, 

promote simplicity or complexity in the forest community, and provide for either paucity or diversity of ecologic services, recreational 

experiences, and economic goods. Thus, the lay of the land and the 

condition of the ecosystem provides the actual size of the ecosystem management unit. Natural drainage patterns, operational restrictions imposed for streamside zones and other fragile-soil areas, 

and the economics of tracking and managing small isolated parcels 

of land also influence management unit boundaries and the resultant character of the landscape. 

Streams are divided into classes (orders) based on their size and 

position in the watershed. The contributions of streams and streamsides to biodiversity differ markedly (Hawkins et al. 1983). Small 

streams and wetlands usually contain detritus-based communities 

supporting amphibians as top predators; many of these amphibians 
C H A P T E R 6 Ecological Foundations of Biodiversity 173

occupy upland communities as adults (Leonard et al. 1993). Larger 

streams usually contain photosynthesis- and detritus-based communities supporting fish as top predators. Additionally, streamside 

biotic communities include species unique to the riparian zone, 

including some amphibians (Olympic torrent salamander), birds 

(American dipper), and small mammals (water shrew). Other species, such as Roosevelt elk, prefer riparian communities over upland 

communities (Raedeke 1988, Woodward et al. 1994). Riparian forests also provide corridors that direct, facilitate, and impede movements of both small and large vertebrates. A minimum landscape 

unit for aquatic communities is the small watershed. 

For the second-level operational building block, the life histories of animals of medium mobility in a terrestrial landscape provide guidance; for example, a pair or two or three of spotted owls, a 

resident fish stock, populations of screech owls, blacktail deer, and 

Roosevelt elk, or multiple populations of northern flying squirrels. 

Managerially, the scale includes the ability to manage for water 

quality, maintain ecological services in the face of small catastrophic 

disturbances (wildfires, windstorms, and timber harvests), produce a 

sustained yield of wood products, and support a small timber mill 

(only a part of a timber-dependent human community). This is the 

scale of watersheds; watersheds are naturally discrete landform units 

(Bormann and Likens 1979, Odum 1971). One or more watersheds 

constitute a landscape. Small watersheds in the state of Washington 

are 6,000 to 20,000 hectares. Small landscapes aggregate into larger 

units that can provide for a population of spotted owls, several populations of the largest mammal—Roosevelt elk, multiple fish stocks, 

metapopulations of amphibians, small mammals, and small birds, 

and a base for local economies. At larger scales, focus is on connectivity and permeability: river systems, ecological corridors (for 

gene flow through dispersal and for migration), and even highway 

systems. Large landscapes are 200,000 to 400,000 hectares. 

Ecological theory explains simply patterns of abundances of a 

wide variety of plants, arthropods, and vertebrates by three factors 

(Brown 1984): (1) each species is limited by a combination of physical and biotic variables that define multidimensional habitats and 

niches; (2) spatial variation is somewhat stochastic but usually autocorrelated; and (3) closely related, ecologically similar species differ 

in no more than a few niche dimensions. The factors that regulate 

the distribution and abundance of a species, however, may vary with 

season (Fretwell 1972). Populations living in seasonal environments 

are exposed to regular changes in resource quality and abundance. 

Within a given space and time, individual animals are faced with 
174 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

choices about which areas or biotic community to inhabit. This 

habitat selection is part of the foundation on which the structure 

of small mammal communities lies (Rosenzweig 1989). Even resource partitioning is mainly achieved by habitat selection. At the 

large scale, the selection is among biotic communities and is called 

habitat. At a fine scale (microhabitat), selection occurs within a biotic 

community. Habitat preferences change more readily than resource 

preferences and are highly density dependent (resource preferences 

are only weakly density dependent). Thus, habitat preferences are 

most easily measured when a species is rare and are likely to decay 

at high densities (overall high resource levels). Habitat selection assumes (Fagen 1988) (1) animals move freely to preferred habitats, (2) 

animals prefer the available habitat offering the highest per capita 

resource availability, (3) resource availability is highly predictable, (4) 

moving between habitats costs little, (5) moving within each habitat 

costs the same as moving between habitats, and (6) individual reproductive success within each habitat decreases as population density 

increases. The fundamental niche of species is the set of environmental conditions and resources that permit a population to persist 

when not limited by competition or predation; this niche can be 

described evolutionarily as the environment in which mean fitness 

is 1 or more and outside of which mean fitness is less than 1. Natural 

selection operates principally as a conservative force to improve fitness within the fundamental niche (Holt and Gaines 1992).

In summary, landscapes are composed of biotopes occupied by 

biotic communities. The array of communities a species inhabits defines its habitat in that landscape. Within a biotic community, a 

species makes use of only a part of the available space; this use is 

dependent on interactions with other species and the space actually 

occupied is the niche (Carey 1981, Hutchinson 1978, Whittaker et 

al. 1973). For example, in the Montane Zone of the Rocky Mountains, Richardson’s ground squirrel is confined by its colonial social 

behavior and habit of denning in burrows to areas of deep, friable 

soil such as meadows and aspen groves; thus deep soil determines 

its habitat. The golden-mantled ground squirrel has a much broader 

habitat; it is capable of inhabiting most of the biotic communities 

in the montane landscape. However, the golden-mantled ground 

squirrel can be excluded from communities on deep soils by the 

aggressive Richardson ground squirrel. In those areas, rock outcrops 

and the Richardson ground squirrel defines the niche of the goldenmantled ground squirrel. The least chipmunk has even a broader 

habitat spanning several zones; but its occurrence in any particular 

area depends on physical aspects of the habitat that allow it to avoid 
B

A C

D

C H A P T E R 6 Ecological Foundations of Biodiversity 175

Figure 30—Habitat is defined 

by the use of a species. Use is often 

measured as density (number of animals per hectare), and density is often 

determined by the use of space. Good 

habitat for both (A) northern flying 

squirrels and (B) Townsend’s chipmunks was provided by old growth, 

and bad habitat for both (C) flying 

squirrels and (D) chipmunks was provided by second growth (adapted from 

Carey et al. 1999b). Shading reflects 

the numbers of captures of the squirrels and the lines represent short-duration foraging patches (flying squirrels) 

and home ranges (chipmunks). Note 

there are unused portions for each species in both stands.

confrontation with other more aggressive chipmunks and ground 

squirrels (Carey 1978b, 1981; Heller 1971). In the Pacific Northwest, 

the northern flying squirrel occupies a wide range of biotic communities. Its abundance, however, varies markedly across those communities in response to various habitat elements that provide food, 

cover, and shelter. The squirrel can be extirpated from communities that are low-quality habitat by predation by long-tailed weasels. 

Even in high-quality habitat, its population density can be reduced 

sharply by predation by spotted owls (Carey et al. 1992). Within 

communities that provide poor-quality and those that provide highquality habitat, the flying squirrel still only uses a fraction of the 

available space (fig. 30). In southwestern Oregon, use seems to be 

conditioned by coarse woody debris and interactions with truffles 

at the fine scale (microhabitat) and diversity of vegetation site types 

at a slightly large scale (habitat breadth) (Carey et al. 1999b) (table 

12). In western Washington, factors determining the niche of the 

flying squirrel seem more related to the presence of mast-producing 

hardwoods in addition to vegetation complexity, abundance of cavity trees, competition primarily with chipmunks, and predation by 

owls and weasels (Carey 1995, 2000a, 2000b; Carey and Harrington 

2001).
Table 12—Population response of northern flying squirrels to environmental variables in Oregona

Response measure Scale Dependent variable(s) Independent variable(s)b Variance explainedc

Potential habitat

(Total habitat space 

sampled)

Points in a 

landscape

	Variance in vegetation structure

	Composition

	Crown-class differentiation (25%), decadence 

(16%), canopy stratification (11%), understory 

development (10%)

	Position on a moisture 

gradient (24%)

63%

24%

Realized habitat Points in a 

landscape

	Presence-absence of 

squirrels

	Decadence (0.8) +

canopy stratification (0.6) 

+ crown-class differentiation (0.3) + understory 

development (0.3)

60%

Habitat quality Among 

communities

	Abundance 	Decadence (17%) + habitat breadth (21%)

50%

Carrying capacity Among 

communities

	Maximum abundance over time

	Decadence (45%) +

habitat breadth (25%) -

position on the moisture 

gradient (16%)

70%

a The entire area sampled was described by the structure and composition of the vegetation; structure could be reduced 

to four independent variables, and composition to one independent variable. Flying squirrels occupied only a part of 

the available space, and this part was described well by the four structural variables. Variance in abundance across the 

biotic communities, however, was best explained by decadence (fallen trees and snags) and by complexity of the vegetation community (habitat breadth). The maximum attainable densities of squirrels were best predicted by decadence, 

habitat breadth, and position on a moisture gradient indicating that rich mesic communities supported higher populations than communities on dry sites or very wet sites.

b Different types of statistical analysis were used depending on the nature of the dependent variable. The values in 

parentheses represent the relative contribution (or importance, which could be negative or positive) of each independent variable in explaining the variance in the dependent variable. These values may or may not sum to the values in 

the variance explained column or to 100 percent because the exact statistical meanings of these values varies with the 

analytical method.

c

 The total percentage of variance explained by the statistical procedure.

Source: Adapted from Carey et al. 1999b.

176 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Communities and Ecosystems

Biotic communities comprise the species occupying a particular 

biotope (site in a landscape) that, together with that site, form a 

local ecosystem that supports those local species populations. Much 

debate has taken place over whether or not biotic communities are 

real assemblages of interacting species or haphazard assemblages of 

species whose composition reflects historical contingencies and random sampling from a regional species pool. The latter reductionist 

view reflects narrow focus and lack of consideration of interactions 

taking place at various levels of biological, spatial, and temporal 
C H A P T E R 6 Ecological Foundations of Biodiversity 177

In the stochastic 

view, there is no 

logical need for 

conservation.



In the systems 

view, conservation 

is required to 

maintain keystone 

species, keystone 

complexes, and 

a species pool 

that provides for 

redundancy in 

functional groups, 

which facilitates 

system adaptability 

and change through 

time.

organization. Such a view is most likely to be held by one who 

focuses on large, immobile organisms, such as tropical trees, that are 

species rich, diverse in dispersal ability, and adapted to environmental homogeneity (Hubbell 2001). The former view is more likely to 

be held by ecologists who must consider competitive, mutualistic, 

host-parasite, predator-prey, and complex food web relationships 

of species of markedly varying mobility and dispersal capability 

coexisting in spatially and temporally heterogeneous landscapes and 

biotopes (Tilman and Kareiva 1997). 

Many of the contentious issues in ecology carry over into the 

applied ecology of forest ecosystem management and conservation of biodiversity. The concept of biodiversity, at its basic level, is 

a community concept. The same can be said of functional groups, 

guilds, niche, ecosystem, ecological succession, forest development, 

biotic integrity, resilience, stability, and forest health. The contemporary question boils down to: Are assemblages of species in place 

and time (1) simply an accident of history built upon by random 

immigrations and extinctions versus (2) a result of a self-organizing 

adaptive system, conditioned by history and drawing from regional 

species pools, but forming assemblages consisting of tightly connected nodes of species loosely connected into a larger system of 

tightly connected nodes (Barabási and Bonabeau 2003, Dunne et 

al. 2002), all within an evolving holarchic system that develops in 

biocomplexity until some major external force causes catastrophic 

collapse, followed by reorganization? In other words, is the basic 

unit of ecology, the ecosystem, a site inhabited by a chaotic or random assemblage of species or an organized, ecological, system? To 

many ecological modelers, statistical ecologists, and mathematicians, arrangements in space and time do seem poorly predictable, 

unstable, and chaotic. To naturalists, often imbued with a tolerance 

of ambiguity born of experiential appreciation of natural wonder, 

the patterns and organization in nature are manifest—familiar and 

predictable but often accompanied by delightful or fearful surprises. 

In the stochastic view, there is no logical need for conservation. In 

the systems view, conservation is required to maintain keystone species, keystone complexes, and a species pool that provides for redundancy in functional groups, which facilitates system adaptability and 

change through time. 

Another major ambiguity in defining, discussing, and studying 

biotic communities is that limiting consideration to a subset of species on a site (or among sites) requires decisions that are somewhat 

arbitrary. Examples of arbitrarily defined biotic communities include 

mosses, lichens, herbs, achlorophyllous mycotrophic plants, shrubs, 

trees, hypogeous ectomycorrhizal fungi, epigeous mycorrhizal fungi, 
178 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 32—Growth form 

(also referred to as growth habit 

or life form)—how plant species 

are put together and shaped, such 

as forbs, grasses, lichens, shrubs, 

trees, vines, etc. (Grime 1977).

litter arthropods, forest-floor mollusks, forest-floor salamanders, 

Neotropical migratory birds, forest-floor small mammals, arboreal 

rodents, and bats. Certainly, these groups of species that are moreor-less similar in some aspects of their phylogenies, physiognomies, 

physiologies, and ecologies are more comprehensible than the totality of species, more likely to exhibit apparent niche differences (resource partitioning, differences in trophic relationships) that allow 

explication of system function, and more likely to be keyed to a recognizable subset of elements of forest ecosystem structure or composition—but they are not independent of interactions with other 

species or groups of species, even species at different trophic levels, 

of markedly different sizes, and with various life histories.

Certain aspects of community-level diversity are axiomatic. 

Species diversity within biotic communities generally increases 

with the spatial extent (area) of the community, history of intermediate disturbances, time since last major disturbance up to some 

asymptote, and heterogeneity. Diversity within a specific community can vary markedly with time since catastrophic disturbance, 

with high diversity as the disturbed site is colonized by exploiters 

and low diversity when a few species dominate the system (as in 

the competitive exclusion stage of forest development). Diversity 

increases with differentiation (e.g., crown-class differentiation, or 

development of dominance, codominance, subordinance, and suppression among trees and species of trees, and differentiation among 

microsites owing to effects of dominant plants on light, moisture, 

microclimate, and soil chemistry) arising from interactions (competition, predation, mutualism) that modulate species fluctuation in 

species abundances. Diversity also increases with development of 

spatial complexity arising from accumulation of biomass and smallscale disturbances but decreases (at least for vertebrates and vascular 

plants) in the absence of disturbance as the ecosystem maintains a 

relatively stable quasi-climax state. With succession (replacement of 

one relatively discrete biotic community by another) and development (envelopment) of communities over time in forest-dominated 

systems, the trend is toward increased biomass, a system shift from 

production to maintenance of biomass, vertical stratification by increasing diversity of growth forms (sidenote 32), complexity in arrangement of physical and biological structures in space, diversity in 

species composition, increases in niche complementarity, selection 

for competitive ability, and tightening and slowing of nutrient cycling, as products of community self-organization and self-regulation (Carey et al. 1999b, Franklin et al. 2002, Margalef 1968, Odum 

1969, Pickett 1976, Whittaker 1972). 

Note, the difference between succession—replacement of a grass 
C H A P T E R 6 Ecological Foundations of Biodiversity 179

community by a shrub community by a tree community or replacement of a deciduous tree community by a conifer-dominated community—and development. Development is a process by which ecosystems (the abiotic and biotic circumstances of a site) expand in 

multivariate dimensions with each expansion enveloping, not displacing, the preceding condition. A young second-growth Douglasfir forest can develop from the competitive exclusion stage, in which 

the firs each attempt to capture as much of the multidimensional 

growing space as possible to the exclusion of weaker firs and other 

members of the community, to diverse communities undergoing 

development of habitat breadth (vegetation-microsite type diversity) and preinteractive niche diversification (these concepts will 

be discussed in detail later). Although, many of the firs maintain 

their positions of dominance for centuries, most of the originally 

scarce species increase in abundance, and new species are recruited. 

Thus, species diversity is not an unchanging property of a community. Species extinctions, speciation, and invasions occur at multiple 

scales simultaneously. 

Biological diversity decreases in systems exploited by humans. 

In exploited ecosystems, community succession and development 

are often truncated, the maturity and complexity of ecosystems are 

reduced, and fewer species and life forms produce the bulk of the 

biomass. Management often deliberately simplifies biotic communities and sometimes even the physical variability of the ecosystem. 

Even the structure of the soil may be simplified with a concomitant 

decrease in the diversity of soil organisms. Weeds and pests increase 

rapidly and disperse easily. Strong exploitation of very mature ecosystems may produce a total collapse of a rich organization (Margalef 1968). The root causes of loss of biodiversity are often stated 

to be destruction and fragmentation of natural plant communities, 

although pollution, invasion by exotic species, overharvesting of resources, and disease can be important (Wilson 1999a). Conversion 

of forest, wetlands, and grasslands to farmland, suburban, urban, and 

industrialized areas in eastern North America resulted in some extinctions, multiple widespread extirpations, and reduced vertebrate 

populations and led to the Federal Aid to Restoration of Wildlife 

and Fish Acts in 1937 and 1950 (Allen 1954). Nevertheless, the same 

patterns of exploitation and loss of biological diversity continued in 

western North America (Lee 1993). 

Diseases, such as chestnut blight, Dutch elm disease, white-pine 

blister rust, and many others have had profound effects on composition and structure of forest communities. The effects of epidemic disease and reduced biodiversity may be acute in the short 

term but still produce chronic results. For example, chestnut blight, 
180 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

fire exclusion, agricultural clearing, clearcutting for timber harvest, 

and purposeful increases in deer populations disrupted a dynamic 

equilibrium among upland oaks to the extent that white oak, once 

supreme among oaks prior to the arrival of Europeans in eastern 

North America, is in dramatic decline (Abrams 2003). The most 

dramatic example is a drop from composing 33 percent of all oaks to 

9 percent in eastern West Virginia. Such compounded perturbations 

have produced similar ecological surprises in a variety of systems 

(Paine et al. 1998). Shifts to some alternative relatively stable state of 

lowered diversity in response to slow change or chronic stress may 

occur dramatically and rapidly (Holling 1986, Scheffer et al. 2001).

Self-Organizing Systems

What is this idea of self-organizing systems? R.H. Whittaker 

(1969) described organization as the means by which functioning 

complexity is maintained through time. Salient organizing principles include competitive interplay (leading to niche structure) 

and adaptive diversification (leading to complex food webs). Thus, 

diversity increases during development, and overall diversity in treespecies-rich broadleaf forest tends to be higher than in evergreen 

conifer forests dominated by a few tree species. Diversity of vascular 

plants tends to decrease with decreasing environmental stability and 

increasingly extreme conditions that might interfere with development of greater organization and complexity. The diversity of a 

community, then, is a form of complexity, of organized differentiation, and expresses the kind of organization—competitive interplay, 

role differentiation, and diverse interactions—tending to modulate 

community fluctuation. Microsite variation alone is insufficient to 

provide for even the diversity of tree species; interactions among 

dominants and subordinates and among species are key (Fox 1977). 

Positive interactions (mutualisms and facilitation) play a critical role 

in ecological communities by reducing physical and biotic stresses 

and by contributing to development (or even creating new biotic 

communities) on which many species depend (Mulder et al. 2001, 

Stachowicz 2001). Simply by growing, many species alter their local 

environment by shading, blocking the wind, intercepting precipitation, and altering soil chemistry by their litter and exudates. Mutualists, such as ectomycorrhizal fungi on the roots of conifers and rumen bacteria and protozoa in the four-chambered stomachs of deer 

and elk, are essential to nutrient transfer and trophic facilitation. 

Some species are ecosystem engineers, and modify the environment 

by their activities (e.g., American beaver and the big-time excavator 
C H A P T E R 6 Ecological Foundations of Biodiversity 181

Sidenote 33—Current 

understanding of Panarchy theory 

(Holling 2001):

 Multiple stable states are common.

 An adaptive cycle is the 

fundamental unit of dynamic 

change.

 Not all adaptive cycles are the 

same; some are maladaptive.

 Sustainability requires both 

change and persistence.

 Self-organization shapes longterm changes.

 There are three types of learning—incremental, lurching, 

and transforming.

 The world is lumpy.

 Functional diversity builds 

resilience.

 Tractability comes from the 

rule of hand (X>3).

 Emergent behavior emerges 

from an integrated system.

 Management must take surprise and unpredictability into 

consideration.

 Adaptive management outperforms optimization for stable 

targets.

of trees, the pileated woodpecker). Less obvious engineers are woodboring insects and decay-causing fungi. These species provide critical 

habitat elements for numerous species including refuge (protective 

cover and protected nest sites) from physical stress, predation, and 

competition. Diversity within functional groups like ectomycorrhizal fungi and bryophytes is thought to help maintain an ecosystem 

through environmental change and under environmental stress.

When self-organizing forces for evolution of diversity interact 

with the technological capacity of postindustrial socioeconomicenvironmental systems, a predicament arises. A system of accelerating growth and increasing complexity stretches ever tighter the 

means of organization while producing social and environmental 

problems ever more difficult and beyond realistic prospects of solution, increasing tensions and frustrations of people who must maintain the organization and try to deal with problems, and producing 

increasing numbers of people who scorn the system and its complexities without a rational sense of the limitations on alternatives 

(Whittaker 1969). Thus, Holling (2001) incorporates social, economic, and environmental levels in the hierarchies of Panarchy theory to 

examine how we might move toward sustainability, which he defines as the capacity to create, test, and maintain adaptive complexity while maintaining development—the process of creating, testing, 

and maintaining opportunity. He defines self-organization as the 

development of complex adaptive systems in which multiple outcomes are possible and dependent on accidents of history. Diversity 

and the individuality of components, localized interactions among 

components, and an autonomous process that uses the outcomes of 

those local interactions to select a subset of those components for 

enhancement are characteristic of complex, adaptive systems. Thus, 

he states, if sustainability means anything, it has to do with the small 

set of critical self-organized variables and the transformations that 

can occur in them during the evolutionary process of societal development. Thus, Holling (2001) suggested a dozen truisms (sidenote 

33). Panarchy theory describes how a healthy sociological system 

can invent and experiment, benefiting from inventions that create 

opportunity while it is kept safe from those that destabilize. Panarchy theory is discussed more in depth later, but now let’s return to 

some fundamentals of biological diversity.

Formation of Biotic Communities

Various theories provide different perspectives on how species populations assemble into biotic communities (Belyea and Lancaster 
182 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

1999, Gotelli 1999). Trait-environment theory posits that certain 

traits of individual species allow those species to occur together in 

specific biotic communities. Island biogeography theory asserts that 

assembly incorporates competition and stochastic colonization processes. Contingent ecology relates that assembly is conditioned by 

the specifics of the locality and its history. Deterministic ecology 

claims that community assembly conforms to some general principles. Fundamental principles that apply widely in community formation are called assembly rules. These rules constrain the behavior 

of the assembly process and arise from various processes occurring 

within the community. The same rule may apply to communities 

that differ historically and may lead to similar or to divergent trajectories, depending on a number of variables, including regional 

species pool, specifics of the locality, and specifics of history. As far 

as we can tell, dispersal constraints, environmental constraints, and 

internal dynamics of populations within communities interact to 

select species that not only can coexist but also interact to increase 

biomass and to produce nonrandom spatial distributions of species. 

Dispersal constraints determine the pool of potential colonists and 

result from species-specific traits, storage effects, landscape ecology, and history. Environmental constraints restrict species establishment and mediate interactions among residents and successful 

colonists. Environmental changes can lead to changes in communities. Assembly rules are general and mechanistic and operate within 

the situation-specific constraints imposed by colonization sequence 

and environment. An example of a rule is the proportion of total 

resources consumed increases as each additional species invades. 

Internally, species compete for the same resources within, but not 

between, functional groups. This rule suggests that a common pattern should be that invading species are likely drawn from different 

functional groups until each group is represented, before the pattern 

repeats itself. As resource use increases within a functional group, 

interspecific competition increases, and species overdisperse to minimize niche overlap. Rules operate within and across trophic levels 

and whole systems through resource dynamics and spatial dynamics 

to select sets of coexisting species. The interaction of an assembly 

rule operating at one level of community organization (e.g., within a 

functional group) with a rule operating at another level of organization (e.g., across trophic levels) may lead to patterns of community 

structure that could not be predicted from either rule working independently. This phenomenon can be viewed as an emergent property 

of self-organization as well as evidence of a chaotic system.

A.S. Watt (1947), in his presidential address to the British Ecological Society, emphasized a patchwork mechanism of community 
C H A P T E R 6 Ecological Foundations of Biodiversity 183

assembly. Aggregates of individuals and species form different kinds 

of patches—these patches form a mosaic that constitutes the community; thus, recognition of patchiness is fundamental. Patches (or 

phases) are dynamically related to each other, and when this dynamic produces orderly change, there is persistence in the community pattern. Much later, Ives et al. (2000) argued that complex 

communities composed of modular subcommunities lead to community stability and species richness. Departures from the inherent tendency to orderliness may be caused by fortuitous (stochastic) 

obstacles to the normal sequence of events, with the final community structure resulting from causes of order and causes of disorder 

(Watt 1947; note the similarity to the self-organizing system that 

produces order out of chaos). Watt emphasized relationships among 

components of ecosystems in space and time, saying these relationships constituted the primary means of maintaining the integrity of 

the community. Thereby, he argued for communities defined as homogeneously diverse dynamic assemblages with a recognizable pattern just as Hutchinson (1978) did 30 years later. Watt described the 

community as a space-time mosaic, wherein each patch is dependent on its neighbors and develops under conditions partly imposed 

by them. Watt (1947) provided examples from diverse biotic communities—bogs, bracken-grass heaths, beech-birch woods, tropical forests, and others. He emphasized process over structure—the 

thing that persists is the process and its manifestation in space-time 

patterns. Emphasis on process over structure is essential for effective 

management and conservation of naturalistic ecosystems (Carey 

2003a, 2003c; Carey et al. 1999b) and is a theme of this book. Like 

Holling (1969) 20 years later in his adaptive cycle and Bormann 

and Likens (1979) 30 years later in their studies of the dynamics 

of northeastern forests, Watt (1947) talked about a cycle of change 

with an upgrade phase that accumulates biomass and develops habitat potential and downgrades that can come about through insects, 

diseases, and physical disturbances. Time and again, throughout the 

brief history of ecology, the same phenomena become repeatedly 

recognized for their importance and are renamed and reincorporated into ecological theories that provide us with a broader and 

deeper understanding of how nature works. Patchiness provides a 

diversified (spatially heterogeneous) environment providing diverse 

regeneration niches for plants and fundamental niches of animals 

among the various patches. Dynamic processes and environmental 

heterogeneity within the community are important determinants of 

biological diversity (Huston 1979). 

Chesson (2000) provided yet another, different, perspective 

on community organization by asking what mechanisms maintain 
184 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

species diversity. How do species coexist? Coexistence mechanisms 

function in two ways: (1) equalizing—minimizing the average difference in fitness among species and (2) stabilizing—increasing negative intraspecific interactions over negative interspecific interactions. 

Stabilizing mechanisms are essential for coexistence and include 

resource partitioning, frequency-dependent predation, and mechanisms that depend on fluctuations (variability) in population densities and in environmental factors in space and time. Complementarity in resource use leads to higher net primary production, a broader 

base for diversity (Hooper 1998). Complementarity or partitioning 

of resources by plants comes about through difference in rooting that 

affects access to water and nutrients, difference in architecture that 

helps fill aboveground space more efficiently, differences in phenology that allow different species to harness the same resources, but 

at different times of the year, and differences in physiology that lead 

to differences in type of nitrogen used or sources for phosphorous. 

Some species aid the growth of other species through provision of 

resources or amelioration of harsh environments in a process of facilitation. For example, some species fix nitrogen in a form available 

to other species, whereas some shade the soil and conserve moisture 

and alter the microclimate, providing niches for other species. Finally, the interplay of behavioral, biological, chemical, physical, and 

social interactions that affect, sustain, or are modified by living organisms in the community brings about biocomplexity. 

Biocomplexity arises as temporal, conceptual, and spatial boundaries are breached and the system exhibits emergent, or unexpected, 

properties—in other words, the whole of system behavior is greater 

than the sum of the parts (Michener et al. 2001). For example, in Arizona, with large crown fires in the absence of elk, there is a positive 

relationship between severity of fire and regeneration of aspen via 

asexual reproduction; sprouting is 10 times greater at high fire intensities than intermediate intensities; there is virtually no regeneration 

without fire. Elk selectively browsed aspen ramets after high-severity fires, two times more than after intermediate-severity fires, thus 

largely negating the increased regeneration. 

Fire and elk had different effects on arthropods (53 taxa in 11 orders and 21 families). Fire alone had no effect, but fires of intermediate severity, followed by elk browsing, increased arthropod diversity 

by 30 percent and abundance by 40 percent. Severe fire followed by 

browsing reduced diversity by 69 percent and abundance by 72 percent. The interaction of fire and elk produced four types of arthropod 

assemblage within the community mosaic, overall a marked increase 

in diversity. Thus, scaling up from populations to community-level 
C H A P T E R 6 Ecological Foundations of Biodiversity 185

interactions revealed unexpected outcomes; greater complexity (in 

time, space, and multiple factors) produced reversal of effects, unexpected outcomes, or emergent properties (Bailey and Whitham 

2002).

Ecosystem Structure

Structure is another term frequently used in forest ecology and conservation that means different things to different people. According 

to the dictionary, a structure is something made up of a number 

of parts put together in a particular way. Chad Oliver (Oliver and 

Larson 1990) uses structure to refer to his stages of stand development (stand initiation, savanna, stem exclusion, understory reinitiation, and old growth) and talks about structure-based management 

in which landscapes are intentionally managed to contain a variety 

of structures (stages of stand development). Structure is also defined 

as the way parts are put together; for example, forest ecologists will 

select a number of variables to measure to describe the structure of 

a particular forest or to compare the structures of forests of different histories. With this meaning, Spies (1998) suggested that forest 

structure is both a product and a driver of ecosystem processes and 

biological diversity. Franklin et al. (2002) described the structural 

development of natural forest ecosystems and its implications for 

forest management and conservation. 

Important components of structure include live trees of various sizes, vertical foliage distribution, horizontal variation in canopy 

density, and coarse woody debris. Note that limiting structure to 

these types of variables is just seeing trees for the forest—trees do 

provide physical structure but not all structure (table 13) (figs. 31AE). The structure of narrowly defined biotic communities can be described in terms of species richness, evenness, and ranking of species 

(Carey 1991, 1995; Carey and Harrington 2001; Carey and Johnson 

1995; Carey and Wilson 2001). Populations of a species are often 

described in terms of age structure and its implications for future 

growth of that population. Closely related to the concepts of structure are architecture and growth form. 

Architecture is sometimes used to refer to how tree growth 

(how the bole, branches, bark, and foliage are put together) differs 

among species. Tree architecture can influence environmental conditions such as light and precipitation penetration through the tree 

crown, and it may provide diverse sites for occupancy by a variety 

(continued on page 188)
0

20

40

60

80

100

120

140

160

180

200

220

240

260

280

> 100 cm

50-99 cm

10-49 cm

Young Mature Old

Stand age class

Number of trees per hectare

A

Number of snags per hectare

Stand age class

0

5

10

15

20

25

30

35

40

45

50

55

60

65

> 100 cm

50-100 cm

20-49 cm

10-19 cm

Young Mature Old

B

Table 13—Key structural attributes of Pacific Northwest oldgrowth forests identified before and after systematic study in western 

Washington and Oregon

Before study After study

	Large live trees 	Diverse tree sizes

	Diverse tree species

	Large standing dead trees 	Abundant live and dead trees with 

cavities

	Large fallen dead trees 	Dead organic biomass is high, but 

composition and abundance differ 

among forest types

	Horizontal heterogeneity 	Horizontal patchiness 

	Diverse patch types

	Multilayered canopy 	Canopy gaps

	Variable foliage height diversity

	Biocomplexity

Source: Adapted from Carey et al. 1999a and Franklin et al. 1981.

186 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 31—(A) Number of trees 

per hectare by diameter at breast 

height (dbh) in young, mature, and 

old stands of the southern Oregon 

Coast Range. (B) Number of snags 

per hectare by dbh in young, mature, 

and old stands of southern Oregon 

Coast Range (adapted from Carey et 

al. 1991). (C) Foliage-height profiles 

(percentage of cover by canopy layer) 

in managed and old-growth forests. 

(D) Coarse woody debris cover in 

northern flying squirrel habitat and in 

Oregon and Washington old growth 

and managed forests (adapted from 

Carey et al. 1999b). (E) Biocomplexity in old-growth and two samples of 

second-growth forests on the Olympic 

Peninsula (standardized to 10 for old 

growth); the degree to which complexity of small mammal communities 

differs from those in old growth and 

overall relative abundance of small 

mammals (adapted from Carey and 

Harrington 2001).
0

5

10

15

20

25

30

35

40

45

50

55

60

65

Managed

Old growth

Overstory Midstory Shrub Herb

Structure variable

Cover by canopy layer (percent)

C

0

2

4

6

8

10

12

14

Washington

Oregon

Habitat Old growth Managed

Stand type

Coarse woody debris cover (percent)

D

0

1

2

3

4

5

6

7

8

9

10

Second growth

Second growth

Old growth

Small

mammal

relative

abundance

Differences

from old

growth

Forest

complexity

A scale of 0 to 10

E

C H A P T E R 6 Ecological Foundations of Biodiversity 187
Table 14—Growth forms and definitions

Growth form Definition

Forb/herb 	Vascular plant without significant woody tissue above or at the ground; forbs and herbs may be 

annual, biennial, or perennial, but always lack significant thickening by secondary woody growth 

and have perennating buds borne at or below the ground surface

Graminoid 	Grass or grasslike plant, including grasses (Poaceae), sedges (Cyperaceae), rushes ( Juncaceae), arrow-grasses ( Juncaginaceae), and quillworts (Isoetes)

Lichenous 	Organism generally recognized as a single “plant” that consists of a fungus and an alga or cyanobacterium living in symbiotic association; often attached to solid objects such as rocks or living 

or dead wood rather than soil

Nonvascular 	Non-vascular, terrestrial green plant, including mosses, hornworts, and liverworts; always herbaceous, often attached to solid objects such as rocks or living or dead wood rather than soil

Shrub 	Perennial, multistemmed woody plant that is usually less than 4 to 5 meters in height; shrubs 

typically have several stems arising from or near the ground, but may be taller than 5 meters or 

single-stemmed under certain environmental conditions

Subshrub 	Low-growing shrub usually under 0.5 meter tall, never exceeding 1 meter tall at maturity

Tree 	Perennial, woody plant with a single stem (trunk), normally more than 4 to 5 meters in height; 

under certain environmental conditions, some tree species may develop a multistemmed or short 

growth form (less than 4 meters in height)

Vine 	Twining/climbing plant with relatively long stems, which can be woody or herbaceous

Source: USDA National Resources Conservation Service 2004.

188 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

organisms from spiders in furrows in rugose bark to lichens, mosses, 

and liverworts on branches. Architecture is also used to refer to how 

forest canopies are put together and how variation in canopy architecture might influence ecosystem processes and biological diversity 

(Carey 1994). 

Growth form is a more general concept about how plant species are put together and differ from other species, for example, 

forbs, grasses, lichens, shrubs, and trees (USDA National Resources 

Conservation Service 2004) (table 14). Growth form has obvious 

implications for ecosystem structure. Small-scale architecture—e.g., 

how twigs and leaves or needles are put together—influences plant 

physiology and tolerance for a range of environmental conditions, 

such as light, temperature, and moisture. Growth form also affects 

a plant’s competition strategy (Grime 1977) (table 15). However, architecture and growth-form concepts illustrate that structure and especially function are often not independent of species composition. 

Species composition affects various ecosystem functions in multiple 

ways in and beyond contribution to structure, for example, production of chemical leachates, nitrogen fixation, support of mycorrhizal 

activity, phenology of fruit and seed production (food for animals), 

(continued from page 185)
Table 15—Plant characteristics of the three primary competition strategies

Plant characteristic Competitive Stress tolerant Ruderal

Shoot morphology 	High dense canopy; 

extensive lateral spread 

above- and belowground

	Extremely wide range 

of growth patterns

	Small stature; limited 

lateral spread

Leaf form 	Robust, often 

mesomorphic

	Small, leathery, or 

needle

	Various, often 

mesomorphic

Litter 	Copious, often 

persistent

	Sparse, sometimes 

persistent

	Sparse, not usually 

persistent

Maximum potential 

growth rate

	Rapid 	Slow 	Rapid

Growth form 	Perennial herbs, shrubs, 

and trees

	Lichens, perennial 

herbs, shrubs, and trees 

(often very long lived)

	Annual herbs

Leaf longevity 	Relatively short 	Long 	Short

Leaf phenology 	Well-defined peaks 

of leaf production 

coinciding with 

period(s) of maximum 

potential productivity

	Evergreens with 

various patterns of leaf 

production

	Short periods of leaf 

production in period 

of high potential 

productivity

Flowering phenology 	Flowers produced after 

(or, more rarely, before) 

periods of maximum 

potential productivity

	No general relationship 

between time of 

flowering and season

	Flowers produced at 

the end of temporarily 

favorable period

Proportion of annual 

production to seeds

	Small 	Small 	Large

Source: Grime 1977.

C H A P T E R 6 Ecological Foundations of Biodiversity 189

digestibility of foliage, production of toxins (e.g., phenols) in foliage, resistance or propensity to disease, insect attack, and decay, and 

many other phenomena that markedly influence species interactions. 

For example, Douglas-fir is relatively decay resistant after injury and 

provides decayed wood for excavation by woodpeckers usually only 

after death of a major part of the tree; long-lasting fallen Douglasfir provide regeneration niches for various plants and an important 

habitat element for numerous animals. Grand fir commonly experiences heart rot while alive and provides dens for American marten 

after the tree falls. Ponderosa pine and western redcedar may undergo substantial heart rot to the extent of producing a hollow, live tree 

useful for denning by American black bears and squirrels and roosting by Vaux’s swifts and pileated woodpeckers. Unfortunately, many 

forest ecologists and wildlife biologists bend the third meaning of 

structure (an organ or part of an organism; something constructed) 
190 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Ecological 

correlates of 

ecosystem function 

in natural oldgrowth forests with 

all its biocomplexity 

do not have the 

same correlation 

with function 

in a simplified, 

managed forest.

to refer to individual elements of the ecosystem, for example, referring to a snag (standing dead tree) as a structure or providing the 

various structures (in the sense of the elements of the habitat) that a 

species needs. Thus, one forest ecologist may discuss structure-based 

management and mean the management for a limited number of 

stages of stand development in a landscape, another may be referring 

to managing tree species composition and tree growth to replicate 

some idealized stage of structural development of forest ecosystems, 

and a third may be discussing how to provide the individual components of a forest thought to be important to either individual species 

or a variety of species of wildlife. Again, such emphasis on structure 

without careful consideration of processes may not at all produce 

the desired outcomes. Stand structural stages based on tree size class 

and diameter at breast height (d.b.h.) do not address most aspects of 

biocomplexity. Idealized stages of structural development based on 

tree sizes do not necessarily correlate well with ecosystem function 

because they do not address composition and internal dynamics, or 

if they do, they do so superficially. Ecological correlates of ecosystem 

function in natural old-growth forests with all its biocomplexity do 

not have the same correlation with function in a simplified, managed forest. For example, d.b.h. and variance in d.b.h. can discriminate among managed young, naturally young, naturally mature, and 

naturally old forests, and thus would be correlated with the functions of old forest, such as providing habitat for spotted owls. Yet, 

these old, natural forests are complex—spatially heterogeneous, 

structurally diverse, biologically diverse, and dynamic. Plantations 

can be managed to produce large trees and even trees of two age 

classes and thus, trees of large d.b.h. and high variance in d.b.h. Yet 

these forests are often simple in structure despite having two canopy 

layers—dominated by a few species and reasonably static—continuing to accumulate biomass in trees, but failing to partition biomass 

among growth forms, produce structure through decadence, and 

maintain a dynamic, spatially heterogeneous environment. There is 

a great and inexorable tendency to reduce ecosystem management 

to the provision of a limited set of static elements—trees of large 

d.b.h., snags of large d.b.h., logs of large d.b.h.—without understanding that processes are functions. These elements set as goals are 

actually intermediate products of complex processes; the dynamics 

of the system are more important than a few simple elements. An 

example of the latter is the importance of intermediate disturbances 

to the maintenance of biological diversity in forest ecosystems (the 

Intermediate Disturbance Hypothesis).
Table 16—Stages of forest development based on ecological processesa

Generic 

model

Timber/wildlife 

(duration in years) Natural development Active management Simple Complex

Stand 

initiation

	Grass-forb (2 to 5)

	Shrub (3 to 10)

	Open sapling-pole 

(8 to 20)

	Disturbance and legacy 

creation

	Cohort establishment

	Ecosystem 

reorganization

 

Stem 

exclusion

	Closed saplingpole-sawtimber (40

to 100)

	Canopy closure

	Competitive exclusion

	Biomass accumulation

	Canopy closure

	Competitive exclusion

	Biomass accumulation









Understory 

reinitiation

	Large sawtimber 

(10 to 100)

	Maturation

	Vertical diversification

	Understory reinitiation

	Canopy stratification

	Niche diversification











Old growth 	Old growth (200

to 700)

	Climax (700+)

	Horizontal diversification

	Pioneer cohort loss

	Natural old growth

	Natural climax





a Stages used in a generic model of forest development contrasted with structure-based timber classes used in a wildlife habitat relationship model, a model of Douglas-fir forest development under natural conditions, and a model for 

active ecosystem management.

Source: Adapted from Carey and others 1999b, Brown 1985, Franklin and others 2001, Oliver 1981, Oliver and Larson 

1996.

C H A P T E R 6 Ecological Foundations of Biodiversity 191

The dynamics of 

the system are 

more important 

than a few simple 

elements.

Forest Structuring Processes

Once a forest has been established, there are four basic internal processes that develop structure over time: crown-class differentiation, 

decadence, canopy stratification, and understory development (Carey et al. 1999b). Nevertheless, conditions immediately prior to and 

during establishment (type of catastrophic disturbance, extent of 

disturbance, duration and repetition of disturbance, degree of legacy 

retention, landscape context) influence how the forest develops. As 

complexity of structure develops, overall habitat space increases—a 

process of development of habitat breadth. The increase in dimensions of the community allows for preinteractive niche diversification. In the 500- to 1,000-year continuum of development of natural, 

old-growth forests, numerous structural stages may occur (Franklin 

et al. 2002). In managed forests, however, some processes may be 

eliminated, others truncated, and some accelerated; complexity may 

be restricted or enhanced; thus, a variety of states of development 

can be identified but these do not constitute a continuum—that is, 

they are not necessarily inevitable, inexorable, sequential, or even 

conducive to continuing development of complexity (tables 16, 17, 

and 18).

(continued on page 194)
Table 17—Potential stages of development in managed, second-growth Douglas-fir forests with approximate 

correspondence to stages of stand development and structural conditions

Stage of development Management and subsequent ecological processes

Ecosystem reorganization: 	Removal of a majority of overstory trees with minor to major retention of biological 

components (future legacies) is followed by planting or seeding of trees, colonization 

by vagile forest species and by native and exotic invasive nonforest species, and succession from bare ground to grass-forb-herb communities to shrub-tree communities to a tree-dominated community.

	Referents: Stand initiation; 6 conditions (as identified by Johnson and O’Neil 

2001)—grass/forb-open to sapling/pole-moderate

Simple 	Clearcutting variants, site preparation, planting, vegetation control, and stocking 

control produce an even-aged monoculture or a forest dominated by a few tree species with one species dominant.

Complex 	Variable-retention harvest systems with 5 to 30 percent retention of legacies, 

depending on area size and context; reduced and variable site preparation; planting 

with natural regeneration expected to establish multiple species of trees; planting or 

seeding to restore lost native plant diversity if necessary; limited vegetation control 

to ensure full stocking and vegetative diversity; precommercial thinning to promote 

multiple tree and shrub species and forestall competitive exclusion of numerous species.

Competitive exclusion: 	No management beyond ensuring full stocking, selecting desired species, and controlling competitors.

	Referents: Stem exclusion; sapling/pole-closed, small tree-single story-closed, 

medium tree-single story-closed, large tree-single story-closed

Simple 	Trees fully occupy the site and compete intensely with one another and other plants 

for light, water, nutrients, and space by growing tall quickly, eventually overtopping 

and suppressing shorter life forms, and slower growing species and conspecifics.

	Self-thinning produces even spacing and, sometimes, reduced intertree competition; 

failure to self-thin leads to loss of crown depth and spindly trees; competitive exclusion may extend to a majority of vascular plants, invertebrates, and wildlife.

Complex 	As above, except legacies from the preceding stand (from fallen trees to stumps to 

patches of intact forest) provide refugia within the forest for a wide variety of species; refugia maintain some spatial heterogeneity and species diversity; suppressed 

trees may provide substrate for cavity-excavating wildlife and foraging for saprophytic insects and insectivorous birds and mammals.

Biomass accumulation: 	Management includes conventional thinning to moderately high relative densities, 

selection for desirable timber species, and removal of decadent, defective, and competing trees.

	Referents: None; sapling/pole-moderate, small tree-single story-moderate, medium 

tree-single story-moderate, large tree-single story-moderate

Simple 	Trees fully occupy the site with moderate intertree competition; even-aged codominants grow and accumulate wood biomass rapidly while providing limited resources 

to other life forms.

Complex 	Low to moderate diversity and biomass of common plant species are maintained; 

growth of dominant trees contributes to maintenance of homogeneity; legacies 

maintain some heterogeneity and diversity.

192 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Stage of development Management and subsequent ecological processes

Understory reinitiation: 	Silvicultural thinning, self-thinning, and natural growth and mortality promote 

dominance by some trees, death of other trees, and release of plants in the understory from overstory competition.

	Referents: Understory reinitiation; sapling/pole-open, small tree-single story-open, 

medium tree-single story-open, perhaps large tree-single story-open, depending on 

stand history.

Simple 	A uniform canopy of evenly spaced trees leads to uniform understory conditions 

with dominance by a few species such as a shade-tolerant conifer or native clonal 

species such as salal and swordfern.

Complex 	Variable-density thinning produces canopy heterogeneity that leads to variable light 

and moisture regimes in the understory, which, together with legacies, produce an 

understory of patches of diverse composition, but generally low in stature.

 When necessary, due to previous management or competitive exclusion, underplanting augments the understory with key deciduous and conifer species.

Understory development: 	Thinning or other mortality reduces competition among trees, increases growth 

of trees, and releases understory from competition; understory develops in stature, 

abundance, and species diversity.

	Referents: None; six small to medium tree-multistory conditions, depending on 

legacies and decadence.

Simple 	A homogeneous overstory with moderate to low crown closure produces an understory that is botanically diverse but still dominated by a few species and lacking a 

distinctive patchy pattern; layers may develop, but lack of legacies precludes a fully 

developed, complex biotic community.

Complex 	Variable-density thinning produces canopy heterogeneity with high to moderate to 

low crown closure by dominants and codominants; heterogeneity produces crown 

class differentiation, including ingrowth by hardwoods and shade-tolerant conifers. 

Variable understory environmental conditions produce understory patches of differing composition.

 Cavity-tree creation and coarse woody debris augmentation during thinning and 

legacies from the preceding forest further compound the heterogeneity.

 The resulting complex structure provides a diversity of niches for species within 

various life forms, including fungi, mosses, lichens, achlorophyllous mycotrophs, 

grasses, forbs, evergreen shrubs, deciduous shrubs, deciduous trees, and shade-tolerant conifers.

Niche diversification  Additional variable-density thinning or group selection may further contribute to 

developing high biocomplexity, including species diversity, structural diversity (live, 

dead, and fallen trees of various sizes; patchy understory; patchy midstory; canopy 

gaps; and gaps filled by shade-tolerant trees growing into the overstory), and vertical 

and horizontal spatial heterogeneity, but the forest still has not developed the giant 

structures characteristic of old-growth forests.

 When needed, cavity-tree creation and coarse woody debris augmentation during 

thinning maintain the decadence process.

 Referents: None; six medium to large tree-multistory conditions, depending on 

numerous variables.

C H A P T E R 6 Ecological Foundations of Biodiversity 193
Stage of development Management and subsequent ecological processes

Gap dynamics  Managed forests more than 125 years old with high niche diversification and trees 

and tree-based structures of giant size, including legacies and the current dominant 

cohort. 

 Either passively managed for late-seral forest values along streams, on mass-wasting 

areas, in watersheds, or in reserves, on long rotations in shifting steady-state mosaic 

landscapes, or with group selection for uneven-age management.

 Referents: Old growth (but not natural); giant tree-multistory, depending on numerous variables 

Source: Adapted from Carey and Curtis 1996, Johnson and O’Neil 2001, and Oliver 1981.

194 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

(continued from page 191)

Legacy retention—After a catastrophe destroys much or all of 

a forest canopy, the ecosystem reorganizes and begins to develop 

anew. The degree of retention of biological legacies from the preceding forest has profound influence on the site and the organisms available to the new ecosystem (Franklin et al. 2002, 2000). 

Legacy retention can range from a few live trees to a mixture of 

trees, shrubs, coarse woody debris, and intact forest floor to entire patches of intact forest. The more legacies retained, the more 

a forest-influenced environment is maintained and the greater the 

mycorrhizal networks, species and sizes of trees, degree of spatial 

heterogeneity, and available species pools. Some important legacies include seeds or seedlings of multiple species of conifers and 

hardwoods, ectomycorrhizal fungi, large coarse woody debris, large 

live trees with epiphytic mosses and lichens, and large dead trees. 

Legacies can provide fuel for future or ongoing disturbance—e.g., 

from the falling of damaged and dead trees owing to decay or wind 

or fires in the accumulated fuel. Legacies and the size and shape of 

the forest that was destroyed determine how distant any particular 

point in the reorganizing ecosystem is from sources of organisms 

that might colonize or recolonize a newly developing forest. The 

landscape context (biotic communities and seral stages) of the reorganizing ecosystem determines which other species are available 

to recolonize a new forest. If a full complement of species is available, four basic processes—crown-class differentiation, decadence, 

understory development, and canopy stratification—determine how 

forests initially develop structurally in the Pacific Northwest and 

many forests elsewhere (Carey et al. 1999b). Each of these processes 

can be jumpstarted by legacies and hastened by active management 

and intermediate-scale disturbances. As basic structuring processes 

interact, two subsequent (higher order) processes—development of 
C H A P T E R 6 Ecological Foundations of Biodiversity 195

habitat breadth (Carey et al. 1999b) and preinteractive niche diversification (Hutchinson 1978)—increase the diversity, composition, 

and structural complexity of the biotic community. 

Crown-class differentiation—After trees have fully occupied the 

site, a tree canopy forms. Initially, the canopy may be dense and 

uniform, but over time, some trees must become dominant and others codominant, subordinate, or suppressed for development to proceed. Crown-class differentiation is important to producing large 

trees, trees with large branches and deep crowns, canopy heterogeneity and rugosity, small dead and dying trees, and a variety of 

other crown and canopy characteristics that develop habitat space 

for a variety of forest organisms. Differentiation can come about 

through (1) retention of coarse woody debris and other elements 

that cause patchy regeneration such as advance regeneration and 

larger trees of different sizes, (2) establishment of multiple species of trees (each with different growth rates), (3) self-thinning, 

(4) small- and intermediate-scale natural disturbances (including 

lightning, fire, windstorms, ice storms, insect infestations, and infections by pathogens), and (5) management (e.g., precommercial 

thinning, commercial thinning, and fertilization). Dense stocking, 

reliance on self-thinning, and tardy, light, evenly spaced thinning, 

however, can forestall differentiation, decrease biocomplexity, and 

lead to instability (Wilson and Oliver 2000). Elements and events 

that produce spatial heterogeneity can hasten the development of a 

complex community. Although crown-class differentiation can take 

place at small scales (one to a few trees), it affects the entire stand 

at larger scales (say 40 to 400 hectares or more). Intermediate-scale 

heterogeneity (0.1 to 0.5 hectare), however, is necessary for development of biocomplexity. Intermediate-scale legacy retention, natural 

disturbances, and management promote not only crown-class differentiation but also the higher level processes leading to habitat 

breadth and niche diversification.

Decadence—Decadence is a complex process essential to biodiversity. Decadent trees (live trees with wounds or active decay, standing dead trees, and fallen, decaying trees) can be retained during 

harvest operations. They can develop naturally as a result of selfthinning, suppression, disease, insect attack, damage by falling trees, 

and weather-related events (lightning, windstorms, ice storms, and 

snowstorms). Or they can be created by intentional wounding, topping, infecting, or killing. Decadent trees have essential roles in 

providing substrate for (1) a large variety of cavity-, hollow-, and 
Table 18—Characteristics of stages of development in managed forests without (simple) and with (complex) 

legacy retention, spatial heterogeneity in the canopy, and maintenance of decadence processes

Stage 

Biomass

allocations Decadence

Spatial

complexity

Niche 

divergencea

Resistance to 

changeb

Ecosystem reorganization:

Simple Trees, herbs, 

shrubs 

None Some Some Low

Complex Trees, shrubs, 

herbs

Much in legacies Much Much Low

Competitive exclusion:

Simple Trees Small trees, deciduous treesSome None High

Complex Trees Legacy logs and 

snags, small trees

Some Some High

Biomass accumulation:

Simple Trees Well-decayed 

small trees

Some Some High

Complex Trees Large legacy 

structures; small 

trees

Some Some High

Understory reinitiation:

Simple Trees, shrubs Possible insect/

disease mortality

Some Some Moderate

Complex Trees, shrubs Variousd Much Much Moderate

Understory development:

Simple Trees, shrubs, 

herbs

Possible insect or 

disease mortality

Some Some Moderate

Complex Variousc Variousd Muche Much Moderate

Niche Diversification

Variousc Variousd Muche Much Dynamic f

Gap dynamics

Variousc Variousd Muche Much Dynamic f

a Niche divergence refers to preinteractive niche diversification in which a variety of ecological niches are provided by 

disturbance, thus reducing competition and promoting complexity.

b Resistance to change indicates stages in which management intervention is particularly important to foster continuing development.

c

 Conifers of different species and age cohorts, deciduous trees and shrubs, evergreen shrubs, ferns, forbs, lichens, and 

bryophytes arrayed in patches that differ in composition and structure.

d Large legacy live trees with decadence, snags, fallen trees, litter, and deep humus; created cavity trees and snags; felled 

trees, insect/disease mortality. 

e Varying in vertical, horizontal, and temporal dimensions.

f

These stages have internal dynamics of change in patches over space in time; still, they are highly resistant to disturbance.

Source: Adapted from Carey and Curtis 1996, Johnson and O’Neil 2001, and Oliver 1981.

196 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
C H A P T E R 6 Ecological Foundations of Biodiversity 197

crevice-nesting wildlife; (2) pecking and tearing foraging by insectivorous birds; (3) physical partitioning of the forest floor that reduces competition between deer and elk and among small mammals; (4) cover for small mammals and salamanders; (5) support of 

invertebrate communities that are prey for insectivorous arthropods, 

birds, small mammals, and amphibians; (6) foraging sites for mycophagous small mammals; (7) travel ways; (8) entryways to subnivean environments; and () rooting and nutrient sources for a variety of plants and fungi (see Bunnell et al. 1999, Harmon et al. 1986, 

and Johnson and O’Neil 2001 for reviews). Typically, forest management for wildlife emphasizes only one or two elements of decadence: large, dead, moderately decayed conifers and large, fallen, 

moderately decayed conifers. The former are the trees most commonly used by cavity-excavating birds, and the latter provide important shelter for terrestrial amphibians and certain small mammals. 

However, to focus on these structures without considering the entire 

process of decadence and how the process differs with seral stage is 

a mistake. For example, a conifer with a broken top may continue to 

grow, develop a new top or “basket” top, develop top rot and provide 

perch, roost, and nest sites for hawks, owls, eagles, ospreys, woodpeckers, squirrels, bats, and various of other wildlife over a long period before it dies and thence long after. In younger conifer forests, 

deciduous trees such as red alder, willow, and aspen provide valuable 

cavity trees despite their relatively small size (Bunnell et al. 1999, 

Carey et al. 1997). For example, red-breasted sapsuckers will nest 

in small decadent willows (20 centimeter d.b.h.) in second-growth 

forests but use only large snags averaging 113 centimeter d.b.h. in 

old-growth forests. Sapsuckers (and other woodpeckers of the family Picidae) are often double keystone species in keystone species 

complexes. For example, in Rocky Mountain forests, red-naped sapsuckers excavate cavities in fungus-infected aspens that are required 

as nest sites by two species of swallows and drill sap wells into willows that provide nourishment for themselves, hummingbirds, orange-crowned warblers, chipmunks, and an array of other sap feeders (Daily et al. 1993). Thus, additional emphasis is warranted on 

providing numerous live deciduous trees, subject to eventual suppression or infection with top rot, early in forest development, and 

both conifers and hardwoods with cavities or other evidence of top 

rot, late in forest development, to provide various sizes of cavity trees 

(relatively small deciduous trees and relatively large conifers). Pileated woodpeckers play a cavity-creation keystone role in Pacific 

Northwest forests (Aubry and Raley 2002) and, actually, throughout many forests in North America. These large birds are capable of 
198 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

excavating nest cavities, entrances to hollow trees, and entrances to 

insect galleries in the interior of large, moderately decayed trees that 

later are used by a wide variety of birds and mammals.

Understory development—Seeds and plants retained on site germinate, regrow if damaged, or continue to grow as light, water, and 

nutrients become available through canopy gaps. Canopy closure 

can extirpate many of the retained species and, if long enough, even 

eliminate seeds from the soil seed bank. In the absence of full canopy closure (limited stocking, disturbance, or management action 

such as precommercial thinning) and with crown-class differentiation, gap formation, or commercial thinning, the understory develops in stature and composition. With sufficient light, the understory 

increases in foliage volume and fruit production, providing invertebrate and vertebrate animals with a variety of food and cover. For 

example, foliage of deciduous shrubs, such as oceanspray provides 

forage for larval moths (Lepidoptera) that are important food to insectivorous birds and mammals (Muir et al. 2002). Vine and bigleaf 

maple seeds and hazelnuts are especially valuable to squirrels in coniferous forests, where their staple foods are produced sporadically (conifer seed) or are of low nutritive value (truffles) (Carey et al. 

1999b, 2002).

Canopy stratification—As canopy dominants attain full stature, 

subordinates die, and disturbances cause gaps through the death of 

canopy dominants and codominants, and canopy dominants lose 

control of the light regime. Increased light to the understory, along 

with retention or recruitment of shade-tolerant conifers and hardwoods, and continued gap formation through natural mortality or 

silvicultural thinning, allows various strata of vegetation—low herbs, 

short shrubs, tall shrubs, and a midstory of deciduous and coniferous 

trees—to develop. Control of the internal light regime now rests 

with the midstory and tall-shrub shade tolerants, and diversity in 

the interior environment of the forest increases. Increased botanical 

diversity may be accompanied by horizontal and vertical heterogeneity in composition and foliage volume. Thus, a large variety of 

trophic relationships develop, and the overall habitat space begins to 

differentiate into diverse niches that support an enhanced variety of 

plants and wildlife.

Development of habitat breadth—With legacy retention and 

following a long period of gap development or management such 

as variable-density thinning, the forest develops patchy overstory, 
C H A P T E R 6 Ecological Foundations of Biodiversity 199

midstory, shrub, and herb layers. The result is a fine-scale mosaic of 

0.1- to 0.5-hectare patches of 10 to 30 vegetation site types with each 

type composed of a different mix of species that differ in growth 

form. For example, one patch may have an understory of moss with 

a dense midstory of shade-tolerant conifers under a relatively open 

overstory; another patch may exhibit a continuous column of foliage from different plants from the forest floor to the overstory. Note 

that the resulting structure is quite different than the development 

of ladder fuels in interior ponderosa pine forests where flammable 

Douglas-fir provides ladders for ground fires to reach canopies. The 

patchy structure resulting from development of habitat breadth includes less flammable species in the understory than in the overstory 

and provides biological and physical gaps in both understory and 

overstory that impede the spread of potentially catastrophic disturbances such as fire and disease. Thus, intermediate-scale heterogeneity has proven beneficial for wet to moist coastal forests (Carey et al. 

1999b) and moist to dry interior forests (Graham et al. 1999, Harrod 

et al. 1999, Reynolds et al. 1992). The process of developing habitat 

breadth (the full range of small-scale vegetation site types, or patches, characteristic of old, natural forests in the region) seems essential 

to the maintenance of biodiversity in two obvious ways. First there is 

an overall increase in habitat space—the volume of space the forest 

occupies, the overall surface area of plants within that volume, and 

the architectural niches formed by the variety of growth forms. Second, the diversity of plant life and growth forms provides a variety of 

substrates and foods (foliage, seeds, fruits, nuts, and carbohydrates 

in root exudates) for use by other plants, fungi, invertebrate animals, 

and wildlife at a scale suitable for exploitation by organisms of low 

to moderate mobility, resulting in niche diversification.

Preinteractive niche diversification—When legacies have been retained or large structures (large live trees, dead trees, and fallen trees) 

have developed and the four basic stage-setting processes have gone 

on to produce habitat breadth, the phenomenon of preinteractive 

niche diversification (Hutchinson 1978) may take place. Simply put, 

the forest has developed sufficient variety in structure, diversity in 

plant composition, and patchiness (and patch types) such that many 

species that typically would compete in simpler environments can 

coexist, even in large numbers. For example, resident cavity-using 

birds overlap in space and resource use in young, simple forests, and 

occupancy of these forests by some of these species may be variable 

or sporadic. In old, complex forests, all are present and in greater 

abundance than in young forest; each tends to forage on different 
200 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

substrates (e.g., bole and branch sizes) and, thus, more separately in 

fine-scale space. Similarly, a variety of decaying plants (wood and 

foliage) produces various sizes of saprophytic invertebrates, each 

primarily consumed by a different insectivorous mammal (e.g., 

shrew, Soricidae) with appropriate-size mouth parts. Diversity in 

foliage cover provides hunting perches for spotted owls and protective cover for their prey. A simple forest may provide the owl with 

one species of prey, but a complex forest provides several species 

of prey (Carey et al. 1992). Thus, a complex forest provides a more 

stable resource for the owl and less predator pressure on any single 

prey species. Niche diversification operates at various trophic levels, 

providing for diverse forest-floor invertebrate fauna, fungi, and vascular plants; diverse insectivorous, mycophagous, granivorous, and 

herbivorous mammals; and diverse predators at the top of food webs 

(Carey 2003a).

Ecosystem Development and Community 

Succession

Diversity begets diversity. However, if the diverse communities are 

all simply structured, have high contrast, or are arrayed in too coarse 

or too fine a grain, species diversity could decrease. Change begets diversity. However, if change is too frequent, too severe, or too 

simplifying, diversity could decrease. Static conditions are thought 

to reduce diversity, but a dynamic equilibrium such as a shifting, 

steady-state mosaic (at either the ecosystem or landscape scales or 

both) may maintain high diversity. Diversity within communities 

generally increases as the ecosystem increases in biocomplexity but 

can decrease over time in stages where stability is high and dynamics 

are low (Whittaker 1965). Diversity in landscapes generally increases with the number of disparate community types in the landscape 

but can decrease in landscapes where disparate community types 

have been deliberately simplified by management for commodity 

production. Few communities, however, are fixed in space and time. 

Most undergo development and many undergo succession. Most 

are eventually affected by some kind or some suite of disturbances, 

natural, anthropogenic, or both. How can one go about sorting out 

all these diverse influences at the larger scales on diversity? Modeling provides the most tractable approach. Of course models are only 

as good as their underlying concepts are sufficient to the purpose 

of the model and the degree to which the incorporated databases 

reflect reality.
C H A P T E R 6 Ecological Foundations of Biodiversity 201

Wildlife-Habitat-Relationships Models

Considerable effort has gone into compiling databases that relate 

species occurrences to community types, stages of community development, and various elements of landscapes (e.g., caves, cliffs, and 

talus slopes) and elements of biotic communities (e.g., snags, coarse 

woody debris, and deciduous tress). For vertebrates, these databases 

are known as Wildlife Habitat Relationship (WHR) models. Similarly, considerable effort has gone into plant community and forest 

type classifications. The WHR databases have several weaknesses; for 

example, (1) they assume static conditions, (2) they do not incorporate measures of resistance to change or susceptibility or probability of disturbance, (3) they generally do not project future trends, 

even in the absence of disturbance, and (4) their models of forest 

development are derived from models of timber growth and yield 

in even-aged stands of trees that serve their intended purpose well 

but are too tree-focused for modeling diversity (e.g., they lack information on biocomplexity). Timber models were not developed to 

account for the diverse elements of wildlife habitat; therefore, they 

serve WHR purposes poorly, unless augmented by numerous other habitat variables. Thus, the most current WHR database for Oregon and Washington ( Johnson and O’Neil 2001) cross-tabulates 

forest–dwelling species by 20 forest structural conditions, 9 habitat 

types, and almost 100 habitat elements and subcategories. Structural conditions include grass/forb—open, grass/forb—closed, shrub/

seedling—open, shrub/seedling—closed, sapling/pole—open, sapling/pole—moderate, sapling/pole—closed, small tree—single story—open, and so on, up to large tree—multistory—closed and giant tree—multistory. Habitat types range from west-side lowland 

conifer-hardwood forest to upland aspen forest. Categories of forest 

habitat elements include down wood, litter, duff, shrub layer, moss, 

flowers, lichens, forbs, fungi, underground plant parts, ferns, herbaceous layer, snags, tree size, mistletoe brooms, dead parts of live trees, 

hollow trees, tree cavities (fig. 32), bark, legacy trees, large branches, 

fruits, seeds, nuts, and edges. Numerous other habitat elements, ecological and abiotic, are tabulated. The cross-tabulated WHR models 

are data-rich and useful but cumbersome. Their complexity exceeds 

the cognitive limits of people engaging in discussions of field conditions or in collaborative management. Still, with careful incorporation into simulation models, they allow exploration of the consequences of alternative conservation scenarios and estimations of 

vertebrate diversity at multiple scales, at least (Carey et al. 1999d). 

However, they generally do not incorporate spatial interactions 
A B

202 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 32—(A) A northern flying 

squirrel and (B) a deer mouse peer out 

of natural tree cavities. Photo A by W. 

Colgan III; Photo B by A. Carey.

among communities. Analysis of spatial relationships in landscapes 

as it relates to species persistence and maintenance of biodiversity 

is in its infancy. Less complex, but still holistic models of forest development are more tractable and can be quite useful for heuristic modeling exercises and designing silvicultural prescriptions. Of 

course, the more reductionist the model, the less predictive ability it 

may have in the real world.

Forest Development Models

The simplest tree-focused model of forest development has four 

stages that follow either a natural or human-created large-scale disturbance: stand initiation, stem exclusion, understory development, 

and old growth (Oliver 1981). This model has proven too reductionist 

for modeling WHR in simulations of Pacific Northwest landscapes 

(Carey et al. 1999d). Carey and Curtis (1996), building on Bormann 

and Likens (1979), went beyond stand-structure classes to a set 

of eight developmental stages based on the processes taking place 

within the forest ecosystem that influence the development of the 
C H A P T E R 6 Ecological Foundations of Biodiversity 203

greater biotic (plant, fungal, and animal) community. Franklin et al. 

(2002) followed with an expanded classification of natural stand development (still focused on trees), nominally based on structure, but 

in actuality incorporating processes (e.g., canopy closure and biomass accumulation) and a large body of literature, including work 

on how stand development differs in managed and natural forests. 

Naturally developing forests may go through as many as eight major 

sequential stand conditions, differing in duration from less than 10

to more than 500 years. However, management can truncate the 

sere of forest development, eliminate entire stages, speed up or slow 

down transition between stages, and produce stand conditions not 

found in natural forests (Carey et al. 1999c, 1999d). Development 

may be limited to as little as 40 years in Douglas-fir forests, yet 

complex forests may require 70 years or more to develop, and forests producing a full array of values may require rotations of 125 to 

250 years or longer (Carey and Curtis 1996). Thus, modeling active 

management and its effects on forest development requires a different type of classification—a nonsequential classification that can be 

subdivided into decadal periods. Furthermore, management for biocomplexity and emergent properties requires that models incorporate more than just the development of the tree community. Carey 

et al. (1999c), for example, modeled the Carey-Curtis 8 stages of 

biotic community development with 25 total substages. Field tests 

of the Carey-Curtis classification in formal experiments, retrospective comparisons of forests managed for various objectives, and in 

retrospective comparisons of managed and natural forests, suggested 

it was necessary to revise and expand the classification to account for 

the great diversity of conditions being produced in managed forests 

in the Pacific Northwest (see table 17). This new classification incorporates seven stages, five of which are cross-classified as simple 

or complex in structure and composition. The stages differ in how 

resources (light, water, nutrients, and space) are being allocated to 

plants, degree of decadence, spatial complexity, niche divergence, 

and resistance to change (see table 18). The latter is an important 

consideration in management because it indicates stages in which a 

relatively stable-state alternative to late-seral forest is likely to develop in the absence of external disturbance. If such a state does 

develop and persist for a relatively long time, it may prove very difficult to alter its trajectory to development of a complex, biologically 

diverse forest (Carey 2003a). In timber management, development 

often is limited to simple subsets of two stages, ecosystem reorganization and either competitive exclusion or biomass accumulation, 

with cycles (rotations) of 40 to 70 years, with few or with a variety 
204 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

of silvicultural manipulations (see tables 17, 19). In management for 

biodiversity, emphasis is on the complex subsets of ecosystem reorganization, understory reinitiation, understory development, and 

niche diversification with rotations of 130 years or more or, with the 

addition of gap dynamics, on very long rotations (say 350 years or 

more). A variety of silvicultural manipulations are used, as well as 

direct wildlife habitat improvements (see tables 17, 19). Despite the 

complexity of this classification, it, like any classification, is an artificial construct and is best applied when augmented with site-specific 

knowledge of environmental conditions (climate, weather, microclimate, and natural disturbance regimes), site fertility and productivity, plant community development, and special landscape elements 

(e.g., wetlands, riparian zones, talus slopes, and cliffs).

Reserve Design

Conservation biologists have taken a markedly different approach 

than wildlife biologists using WHR models to compare alternative 

landscape management scenarios. Conservation biologists have focused on reserve design—how to protect as many of the desired 

communities in the landscape as possible and setting aside areas 

in hope that managed forests might develop into forests similar to 

naturally old forests, despite differences in type of catastrophic disturbance, legacy retention, and probable future natural disturbance 

regimes. They hope future natural disturbance regimes will provide 

the change necessary to maintain high diversity. Which approach 

is better: designating reserves or managing change? Is maintaining 

biodiversity compatible with production of commodities and active management of the land? Is a concept of general sustainability, 

incorporating environmental, social, and economic sustainability 

practical? Are reserves necessary? A case study, the Washington 

Forest Landscape Management Project examined the question and 

provides some insight.

Washington Forest Landscape Management 

Project

Exploitation of forests in the Pacific Northwest over the last 150 

years repeated the history of eastern North America. Small areas 

of natural forest were reserved, and the remaining forests were 

freely exploited. Commercially valuable forests were harvested 
Table 19—Effects of silviculture on ecosystem complexity

Silvicultural treatment

More 

complexity

Less 

complexity

Regeneration harvest:

	Legacy-retention harvest 

	Clearcutting 

Planting:

	With natural regeneration 

	Without natural regeneration 

Weeding:

	Retains some hardwoods and shrubs 

	Removes hardwoods and shrubs 

Precommercial thinning:

	Clumped multispecies retention 

	Systematic single species retention 

Commercial thinning:

	Variable density plusa 

	Systematic minusb 

a Variable-density thinning with mixed-closed, moderately open, and 

open canopies on a 0.1- to 0.5-hectare scale designed to enhance woody 

plant diversity, maintain deciduous trees, promote recruitment of shadetolerant trees with underplanting and augmentation of cavity trees and 

coarse woody debris when necessary.

b Light to moderate thinning with even spacing to favor one species.

Source: Adapted from Carey 2003a and Carey et al. 1999b.

C H A P T E R 6 Ecological Foundations of Biodiversity 205

and replaced with naturally regenerated second-growth forests in 

degraded watersheds. Mounting degradation led to regulatory emphasis on reforestation, efficient production of wood, and economic 

stability (sustained yield), without thorough consideration of cumulative impacts at watershed and higher spatial scales. As harvests of 

old growth proceeded and landscapes became increasingly dominated by early-seral stages, first the spotted owl, then the marbled 

murrelet, and later, numerous salmonids were designated as threatened with extinction. Public concerns led to restrictions on forest 

management. Conservation focus switched from stands of timber 

to landscapes and from wood production to conservation of fish, 

water, and wildlife and to general sustainability. A presidential initiative to resolve the social conflict produced the 1993 Northwest 

Forest Plan for management of federal lands. The plan was an effort 

by disciplinarily diverse academicians, scientists, and managers to 

address environmental, economic, and social concerns. The plan emphasized late-successional reserves, an aquatic conservation strategy, 
206 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

monitoring threatened species, and identification, inventory, and 

management of numerous rare and cryptic species (Staebler 1994). 

In 2002, the plan was judged a failure in need of overhaul by Chief 

Bosworth of the USDA Forest Service because timber production 

projected under the plan was reduced by 75 percent in practice (to 

5 percent of the preplan harvests) because of litigation over species 

sensitive to timber harvest (Dodge 2002, Milstein 2002). Almost 50

percent of the planned timber harvests were to have come from unreserved old growth, and those harvests met especially strong public 

opposition. 

What went wrong with the Northwest Forest Plan? The plan 

failed to address the debate about what constitutes sustainability—a 

debate arising from cultural differences among the three major cultural streams in perceptions, values, and beliefs (see Part I) (Ray 

1996). However, there are lessons learned from implementation of 

the Northwest Forest Plan and recent research that suggest better ways of managing landscapes. Indeed, the plan stressed adaptive 

management. Recapitulation of the federal research response to the 

forest management crisis in the 1980s and the application of new 

knowledge in a congressionally mandated modeling study of crossownership landscape management provide some insights.

Research Response to the Old-Growth Crisis

By 1980, much of the public was dismayed at the continuing harvest 

of old-growth forests. Old-growth forests are 250 to 1,000 years old; 

many are described as cathedral-like, with boles meters in diameter 

sweeping upwards to canopies almost 100 meters tall. People find 

these forests awe-inspiring and spiritual. Scientists postulated that 

old-growth forests were ecologically unique (Franklin et al. 1981) 

and that numerous species of wildlife depended on old-growth 

forests (Meslow et al. 1981), particularly the spotted owl (Forsman 

et al. 1984). Others perceived these forests as warehouses of highly 

valuable timber that would decay if not harvested and that were 

essential to the economic and social stability of timber-dependent 

communities. The onus was placed on Forest Service Research to 

determine quantitatively the uniqueness of old-growth forest, how 

much remained, the extent to which wildlife was dependent on it, 

the species that were dependent on it, the elements of old growth 

those species were dependent upon, the amounts and distribution of 

old growth that should be retained to meet conservation objectives, 

and the degree to which old-growth values could be achieved in 
C H A P T E R 6 Ecological Foundations of Biodiversity 207

managed forests. The USDA Forest Service implemented a coordinated program of research that included replicated, geographically 

stratified studies of plant, reptile, amphibian, bird, and mammal 

communities in old-growth (over 250 years), mature (100 to 200

years), and young (40 to 80 years) natural forests, and the research 

findings have been published (Carey and Spies 1991, Ruggiero et al. 

1991). Later, it implemented a separate program of research on the 

northern spotted owl that included geographically stratified studies of its prey base, habitat use, and demography (Carey et al. 1992, 

1999b). Finally, additional studies compared naturally old forests to 

managed forests (Carey 1995, 2000b; Carey and Harrington 2001; 

Carey and Johnson 1995; Carey et al. 1999b). The results were used 

to design treatments to restore lost biodiversity to managed stands 

(Carey et al. 1999d) and management systems (biodiversity pathways) for small landscapes (Carey et al. 1999c).

Natural Forests

Compared to forests around the world, Pacific Northwest oldgrowth forests are special—the trees are large and long lived, the 

vegetation structure is complex, decaying organic biomass is high, 

and fungal and small mammal communities are especially diverse 

(Carey 1998b). Old-growth forests are heterogeneous as a set, however; members of this set developed on specific sites that differed 

in topographic and biogeographic positions, period of development 

(250 to 750 years), climatic regime, and disturbance regime. Once 

lost, it is unlikely the old growth could be reproduced either through 

natural succession or through intentional management simply because the physical conditions of its development are not subject to 

unvaried natural repetition or to human control. Furthermore, the 

complete species composition of old growth has not been, and currently cannot be, fully determined; thus, indisputable demonstration 

of successful re-creation is impossible. Nevertheless, few species of 

plants and vertebrates are unique to old growth (Carey 1989, Ruggiero et al. 1991). 

The spotted owl, among all vertebrates studied, seemed most 

dependent on old growth given the composition of the landscapes 

of the 1980s (Carey et al. 1992, Carey and Peeler 1995, Forsman et 

al. 1984). Other species were associated with particular elements of 

old growth (see table 13) or undisturbed headwater streams most 

likely to be found in old growth. Numerous species were most 

abundant in old growth but were found in other seral stages as well. 
208 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Often, abundances were associated with one or more attributes of 

old growth that were less abundant in younger or managed forests 

(Carey 1989). Thus, old growth functions differently than many 

younger forests in that its biocomplexity allows greater biomass 

and diversity in a number of narrowly defined biotic communities 

(Carey et al. 1999b, Ruggiero et al. 1991). Many younger natural 

forests with biological legacies from preceding old-growth forests, 

however, support vertebrate communities with greater biomass than 

those in many old-growth forests (Carey 1995, Carey and Johnson 

1995, Carey et al. 1999b, Ruggiero et al. 1991), despite smaller average 

tree sizes. Other young forests support complete biotic communities 

and even provide habitat for spotted owls (Carey and Peeler 1995). 

Thus, it became apparent that management cannot indisputably 

re-create old growth, that any such re-created old growth could 

be regarded as anthropogenic and not wild or natural in any case, 

and that attempts to harvest old growth would be contentious and 

lead to litigation. But, it is not at all clear that forests equivalent to 

old growth will develop from second growth on those same sites if 

simply left alone to organize and grow themselves—they lack legacies, equivalent landscape and regional contexts, and similar climate 

regimes. Improved knowledge of old growth and its importance 

to people suggested that old growth might best be reserved for its 

ecological, scientific, and spiritual values (Carey 1998a, 1998b).

Old-Growth Versus Managed Forests

Whereas as many naturally young forests support biotic communities similar to those found in old growth (Ruggiero et al. 1991), many 

managed forests are depauperate in structure, species, and ecological 

function (Carey 1995, 1998b, 2000b; Carey and Harrington 2001; 

Carey et al. 1996b, 1999b). First, many (but not all) managed forests 

developed without legacies from the preceding forest; these legacies include coarse woody debris, live trees with their mycorrhizal 

and epiphytic associates, and soil seed banks holding numerous native species of plants and animals. Second, most managed forests 

were regenerated as dense monocultures that further reduced native 

diversity through competitive exclusion but allowed exotic species 

to persist, at least in soil seed banks (Carey et al. 1999b, Halpern 

et al. 1999, Thysell and Carey 2001a). In intensively managed forests, brush control, precommercial thinning, herbicides, and commercial thinning all are used as tools to reduce diversity. Indeed, 

stands maintained in the competitive exclusion stage may be more 
C H A P T E R 6 Ecological Foundations of Biodiversity 209

deleterious in terms of biodiversity and landscape function than 

the small areas of clearcutting that would occur with long rotations 

(Carey et al. 1999c). Legacies and often spatially variable, multispecies regeneration in natural stands allow key ecosystem structuring processes to proceed at accelerated rates compared to secondgrowth forests. These processes include crown-class differentiation, 

decadence, canopy stratification, and understory development and 

set the stage for higher level processes that lead to biocomplexity: 

development of habitat breadth and preinteractive niche diversification (Carey et al. 1999b). Understanding processes underlying forest ecosystem development and the structure of trophic hierarchies 

allows formulation of management systems to develop or restore 

biocomplexity to second-growth forests (Carey et al. 1999b, 1999c, 

1999d). Both comparative ecological studies (e.g., Carey 1995, 1998b, 

2000b; Carey and Harrington 2001; Carey and Johnson 1995; Carey 

et al. 1999b; Carey and Peeler 1995) and formal experiments (Carey 

2001, Carey et al. 1996b, Carey and Wilson 2001, Thysell and Carey 

2001a) demonstrate that it is erroneous to assume that forested landscapes are dichotomous (diverse old natural forests versus depauperate young forests), that landscape elements (e.g., early seral stages) 

are unchanging through time, and that second-growth forests will 

develop essential characteristics of old-growth forests without management intervention.

Modeling Landscape Alternatives

Increasing restrictions on forest management with continuing controversy after the Northwest Forest Plan had negative economic 

impacts on rural communities and impeded watershed restoration 

efforts. As lists of species likely affected by timber harvests and other management activities grew, and complexity of management for 

multiple individual species increased, public officials in the state of 

Washington wondered if there was not a better way of pursuing 

economic, social, and environmental sustainability. They requested a 

study to determine if holistic, cross-ownership, management could 

lead to better solutions than landscape zoning and single-species 

conservation plans; an interdisciplinary team of scientists and technical specialists was assembled from the Washington Department of 

Natural Resources, Washington Department of Wildlife, University 

of Washington, Oregon State University, and the Pacific Northwest 

Research Station of the USDA Forest Service (Carey et al. 1999c).

Pragmatic evaluation of management alternatives requires that 
210 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

computer simulations be grounded in reality; thus, the team chose 

a real landscape in western Washington for which detailed data on 

stand conditions, tree growth and yield, streams, wildlife-habitat 

relationships, transportation networks, unstable slopes, operational 

costs, distance to timber markets, and market values were available. 

Because alternatives were to be pertinent to diverse landowners, 

from industrial forests to state-managed school trust lands to tribal 

lands, they calculated net present value of extracted wood products 

and sustainable decadal revenues over the long term (300 years). 

Tradeoffs between economic and environmental values would be 

manifest; however, many values produced would accrue to society 

in general, not to the individual landowner or trust. Thus, public 

subsidies or other benefits might be required as incentives to private landowners. Total landscape management would include nonreserved federal lands and would have to be acceptable to the public 

at large. Thus, these five ecological indices were used to evaluate alternative silvicultural systems and landscape management scenarios 

(Carey et al. 1999c):

 Ability of the landscape to support wide-ranging old-growth 

species, based on estimates of the area of late-seral forest required to support one pair of spotted owls, the only threatened 

species with documented habitat requirements.

 Capacity to support vertebrate diversity based on published accounts of the habitat requirements of 130 species, evaluated as 

percentage of maximum possible capacity.

 Forest-floor function, defined as the biotic integrity of the forest-floor small mammal community (the top of the forest-floor 

food web), based on published equations predicting species 

abundances, and providing part of the prey base for generalist vertebrate predators (weasels, coyotes, bobcats, owls, and 

hawks).

 Ecological productivity, defined as the biomass (kilograms per 

hectare) of three species of squirrels and as representing the 

system’s production of fungal sporocarps, fleshy fruits, and seeds 

of trees (consumed by squirrels) and capacity to support medium-sized predators (weasels, owls, and hawks that consume 

squirrels).

 Production of deer and elk, based on published models, and taken to represent the system’s capacity to support large predators 

(wolves and mountain lions), subsistence hunting by indigenous 

peoples, and sport hunting.
C H A P T E R 6 Ecological Foundations of Biodiversity 211

Given metrics for comparing results, the next choices were on 

constraints on management. The team decided that all alternatives 

should produce a regulated forest that produced a relatively even 

flow of outputs on a decadal basis. Because the existing landscape 

had imbalanced age classes (primarily 50-year-old stands) as a result of rapid harvesting of old growth, achieving regulation required 

up to 100 years. Minimal protection of streams was required by 

state regulations at the time of the simulations, and this protection 

was commonly deemed unsatisfactory; new regulations would be 

forthcoming. Federal land managers had adopted requirements of 

watershed analyses and wide interim buffers around streams, from 

which management was excluded; this exclusion, however, became 

more or less institutionalized. Thus, the state and federal approaches 

provided two extremes, with the state regulations deemed marginal 

at the outset. Applying the new federal approach to the landscape 

produced surprising results—34 percent of the landscape was withdrawn from management, and significant parts of the remaining 

landscape, especially in headwater areas, were so isolated and overdispersed as to become economically infeasible to manage. Similar 

results were obtained as federal managers began implementing the 

new guidelines. The team reviewed federal riparian constraints and 

found, to its surprise, that they were based as much on an upland 

wildlife and dispersal corridor strategy as on an aquatic conservation strategy. Furthermore, there were few empirical data to support 

the corridor strategy, the interim guidelines precluded restoration 

efforts in riparian areas (riparian areas in the landscape to be modeled were highly degraded and devoid of conifers, essential sources 

of coarse woody debris for instream structure), and the constraints 

provided relatively little protection to headwater streams, seeps, and 

mass-wasting areas. The team sought alternatives. First, they shifted 

emphasis from large streams and rivers to small streams; the impacts 

on the entire landscape remained large, and the same suite of problems persisted. Finally, they adopted as a third alternative (to the 

state and federal alternatives), precluding mechanical operations on 

streambanks and adjacent to headwater seeps and streams; allowing thinning and other restoration efforts in narrow riparian buffers, 

but not clearcutting; and allowing thinning, but not clearcutting, on 

mass-wasting areas. The total area in the landscape constrained by 

this approach was less than 15 percent and did not isolate patches 

of upland forest.

Next, the team chose three classes of alternative landscape management scenarios: (1) protection, but no manipulation; (2) maximizing net present value of timber commensurate with existing 
212 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

state of Washington forest practices rules; and (3) management for 

biodiversity, defined as species, biotic communities, and ecosystems, 

and the ecological services and economic goods they provide. For 

maximizing timber production, the team used input from industrial 

forest managers about the feasibility and reasonableness of silvicultural practices and empirical growth-and-yield models. Numerous 

simulations were done, but the final alternative was clearcutting, 

site preparation, natural regeneration, precommercial thinning at 

15 years, clearcutting at 40 years, and existing minimum state riparian management guidelines. Alternative silvicultural regimes for 

conserving biodiversity were developed, too. The final alternative included clearcutting with legacy retention, no site preparation, planting of Douglas-fir and natural regeneration of other conifers and 

hardwoods, regulation of spacing and maintenance of tree species 

diversity with precommercial thinning at 15 years, and variable-density thinning to induce spatial heterogeneity, maintain tree species 

diversity, recruit coarse woody debris, and remove wood products at 

30-, 50-, and 70 years with final harvest by clearcutting with legacy 

retention alternating between 70 and 130 years. Rotation ages were 

deliberately calculated to balance timber revenues with ecological 

outputs. The new riparian/mass-wasting area management was superior to other riparian management alternatives. 

Results of the final simulations were surprising to the team and 

forest managers. Simply protecting second-growth forest caused 

the landscape to go through waves of forest development. Initially 

a substantial ecological crunch occurred because of degraded watersheds and oversimplified stands; a long time (200 years) was 

required for these stands to achieve an old-growth-like condition 

(under a possibly unwarranted assumption that time alone would 

indeed produce naturally complex, old forests). Timber management with minimum constraints produced a landscape inhospitable 

to over 20 vertebrate species and allowed no recovery of degraded 

streams; its sustainability was uncertain, but net present value was 

maximal. Timber management with riparian reserves drawn from 

federal guidelines, produced relatively narrow, well-separated strips 

of late-seral forest in the long term, unlikely to function fully as 

late-seral forest because of their continued adjacency to clearcut and 

young forests; clearcutting was intensified in the available uplands 

owing to removal of streamside and adjacent small patches from 

forest management. Biodiversity management, as it was designed 

to do, produced significant ecological benefits (see Part I, table 5), 

including supporting a pair of spotted owls and producing numbers of deer and elk comparable to the timber management regime. 
C H A P T E R 6 Ecological Foundations of Biodiversity 213

But, surprisingly, costs were relatively low—only a 15-percent loss 

in net present value compared to maximizing net present value of 

timber extraction. Assuming (as occurred) increased riparian protection would be mandatory and eliminating costs of improved riparian/mass-wasting management from comparisons, biodiversity 

management resulted in only a 6-percent decrease in net present 

value. Other economic values increased: decadal revenues increased 

by 150 percent, forest-based employment quadrupled, and the wood 

products manufacturing sector diversified and relied more heavily 

on high-quality wood products and value-added manufacturing 

(Lippke et al. 1996). Initially, the team included a constraint of 30

percent of the landscape in late-seral forest to support one pair of 

spotted owls; the final shifting steady-state mosaic maintained more 

than 50 percent of the landscape in late-seral stages, and less than 15

percent of the landscape was in clearcuts in any decade, resulting in 

a landscape fully permeable to dispersing late-seral species.

Implications

Conservation biologists once argued the relative merits of single, 

large reserves versus multiple small reserves, the need for conserving 

genetic diversity, and the need to restrict active management. Forest 

managers focused on plantation management, transportation networks, and watershed restoration. Now it is becoming recognized 

by both that active management for biodiversity is needed to restore 

degraded ecosystems and to produce fully-functional forests outside 

of reserves. Reserves play important social and ecological roles, but 

they alone cannot conserve biodiversity. Research and experience 

have shown that reserve systems can become self-fulfilling prophecies of highly isolated diverse forests separated by depauperate second-growth forests and developed areas and that conventional timber management can oversimplify forest stands to the detriment of 

stand and landscape function. As human populations grow and increasing demands are placed on our environment, highly intentional 

systems management (Carey et al. 1999c) and total landscape management will be necessary to conserve the biodiversity of naturalcultural mosaics and the ecological services and economic goods it 

provides. Shifting, steady-state mosaics of complex forest ecosystems 

should promote system resilience (Holling 2001). But, the question 

remains, what kind of management can promote biocomplexity and 

what evidence for such management exists. A second case study illustrates some of the possibilities—The Forest Ecosystem Study.
214 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

The Forest Ecosystem Study

In the latter part of the 20th century, it was time to move beyond 

biodiversity reserves into actively managing forests to conserve biodiversity, including communities and ecosystems and the economic 

goods and ecologic services they provide (di Castri and Younes 1990, 

Entwistle and Dunstone 2000). People were demanding both environmental and economic sustainability (Folke et al. 1996, Goodland 

1995, Reid and Miller 1989). In the Pacific Northwestern United 

States, for example, forests are expected to perpetually provide 

commodities; revenues for landowners, schools, and roads; economic support to local communities; habitat for all forest wildlife 

and plants; recreational and spiritual experiences; and clean air and 

water (Carey et al. 1999c, Carey and Wilson 2001). Timber management, however, had simplified forests (Carey et al. 1999b, 1999c; 

Franklin 1993a, 1993b) and contributed to invasion by exotic species 

(Halpern et al. 1999, Hobbs and Humphries 1995, Thysell and Carey 

2001a), imbalanced biotic communities (Carey 2000b, Carey and 

Harrington 2001, Haveri and Carey 2000, Wilson and Carey 2000), 

low prey biomass for vertebrate predators (Carey et al. 1992), and 

poorly functioning food webs (Carey et al. 1996b, 2002; Colgan et 

al. 1999). High-quality timber was becoming scarce and low-quality 

timber overabundant. Environmental degradation and nonsustainable harvests had led to restrictions on harvesting natural forests and 

disruption of local, regional, and even global timber markets. 

In the Pacific Northwest, natural forests and contemporary managed forests differed in structure, composition, and function (Carey 

1995, Carey and Harrington 2001, Carey and Johnson 1995, Carey et 

al. 1999b). Juxtaposed diverse ecosystem elements in natural forests 

contributed to emergent properties associated with biocomplexity. 

The scale of variation in arrangement that contributed to synergy 

was on the order of 0.1 to 0.5 hectare, or 80 to 100 meters (Canham et al. 1990, Carey et al. 1999b). Biotic legacies from preceding 

forest, propagules from adjacent stands, forest developmental processes, and development of spatial heterogeneity all contributed to 

compositional diversity and habitat breadth (diversity of vegetation 

site types). Stand tending for timber, however, purposefully reduced 

complexity and diversity at the local, landscape, and even regional 

scales (Carey 2000b, Carey and Harrington 2001). Consequently, 

population densities of a vertebrate species in managed forests varied 

in complex ways that reflected not only the abundance of its habitat elements, but also abundances of other ecosystem elements that 

determined the overall mix of vertebrate species and the degree of 
C H A P T E R 6 Ecological Foundations of Biodiversity 215

species interactions with one another. Biotic integrity (the structure 

of a narrowly defined community as measured by species relative 

abundances within the community compared to that in old growth), 

nevertheless, varied more or less predictably in response to complexity of vegetation structure and absence of various compositional 

elements because biocomplexity is prerequisite to preinteractive 

niche diversification, community diversity, and ecosystem resilience 

(Carey et al. 1999b, Hutchinson 1978, Tilman 1996). Intentional 

management, nevertheless, should be able to promote biocomplexity (Carey et al. 1999b, 1999c). Retention of legacies of individual live 

trees, dead trees, coarse woody debris, or even patches of forest can 

be used with even-age management systems to jump-start ecosystem development processes. Such variable-retention harvest systems 

transcend traditional silvicultural conventions such as clearcutting 

(Franklin et al. 1997). Thinning inevitably influences all forest developmental processes, including decadence and development of habitat breadth. Variable-density thinning with underplanting offers to 

restore tree species diversity and accelerate understory development 

and canopy stratification. Retaining decadent trees, wounding trees, 

inoculating trees with top-rot fungi, and creating cavities in trees 

should promote decadence essential to ecosystem development 

(Carey et al. 1999b, Franklin et al. 1987). Variable-density thinning 

creates canopy mosaics in second-growth stands and could promote 

vegetative heterogeneity similar to that in old growth (Carey and 

Johnson 1995, Carey et al. 1999b). By removing subordinate and codominant trees, variable-density thinning produces small patches 

such that light, water, nutrients, and space become available spatially 

in various amounts to other vegetation. Effects, however, extend beyond the borders of the altered patches of canopy because of low 

sun angles in the Pacific Northwest. Thus, fine-scale heterogeneity 

creates an even more diverse mosaic of environmental conditions 

and potentially numerous patch types in the understory (Canham 

et al. 1990). Maps of canopy cover and understory plant associations 

revealed natural mosaics of 0.1- to 0.5-hectare patches with a 2:1

ratio of closed to open canopy promote biocomplexity (Carey et al. 

1999b) (fig. 33). Yet, no one had intentionally created such a mosaic 

experimentally or even managerially.

Experimental Design

In 1991, the Forest Ecosystem Study was established as an experiment 

to test the efficacy of various techniques for active management of 
A

B

216 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 33—Recreating spatial heterogeneity characteristic of old forests 

in second-growth forest canopies with 

variable-density thinning: (A) densities 

of trees more than 50 centimeters in 

diameter at 1.5 meters aboveground 

in a 280-year-old Douglas-fir forest—shading (light to dark) represents densities from 3 to 45 trees per 

hectare, based on 225 sampling points 

(from Carey et al. 1999b); (B) relative 

densities of Douglas-fir more than 20

centimeters in diameter at 1.5 meters 

following variable-density thinning of 

a 56-year-old second-growth stand; 

shading (light to dark) represents relative density classes of less than 3.25, 

3.25 to 4.75, 4.75 to 6.75, and greater 

than 6.75 (adapted from Carey et al. 

1999c).

forest to promote biocomplexity (Carey et al. 1999d). The study 

was located southeast of Olympia, Washington, in the Puget 

Trough, a low-lying (120 to 165 meters), flat to rolling plain (Carey 

et al. 1999d). Forests in the Puget Trough had been harvested by 

extensive clearcutting that provided relatively homogeneous forest 

without confounding effects of adjacency of natural forest. As with 

many soils in western Washington, the soils were coarse-textured 

gravelly-sandy loams formed as a result of glacial recession and 

glacial outwash. Annual precipitation was 800 to 900 millimeters 

with only 10 to 15 percent during summer. Vegetation was temperate 

coniferous forest—the Douglas-fir-oceanspray association of the 

Western Hemlock Zone. 

The study incorporated four approximately 100-hectare blocks of 

forest; four 13-hectare plots were delineated in each block (a total of 

16 plots). Each plot was subdivided into 64 (0.16-hectare) cells by an 

8 × 8 grid with 40 meters between grid points and a 40-meter buffer 

around the grid. This grid provided a template for treatments and 

sampling (figs. 33, 34). Two blocks had been clearcut around 1927

and later—more than 10 years prior to the study—conventionally 

thinned twice to a final residual density of 225 trees per hectare 
A F G H

2

1

8

7

6

5

4

3

B C D E

A F G H

2

1

8

7

6

5

4

3

B C D E A B C D E F G H

2

1

8

7

6

5

4

3

2

1

8

7

6

5

4

3

A B C D E F G H

Phellinus pocket

Light thin

Root rot thin

Heavy thin

A

B

C

D

C H A P T E R 6 Ecological Foundations of Biodiversity 217

Figure 34—Actual and potential 

applications of variable-density thinning: (A) Star 101—shows random 

assignment of subtreatments with 

actual root rot pockets, (B) Farley 

302—shows random assignments of 

subtreatments with simulated root rot 

pockets, and (C & D) systematic assignment of light (LT) and heavy thins 

(HT) (as possible operational applications) in a 2:1 ratio of LT to HT (Carey 

et al. 1999c).

(approximately 7 meters between trees). Few trees (less than one 

per hectare) were retained from the preceding old-growth forest, 

and dead trees were removed. Canopy trees were 51 to 54 centimeters in diameter at 1.5 meters aboveground; cover of coarse woody 

debris was 2 to 3 percent; cover of understory vascular plants was 

88 percent, dominated by the evergreen shrub, salal, the evergreen 

swordfern, and brackenfern. Shade-tolerant conifers were rare. These 

plots were called as timber plots. Two other blocks had been clearcut around 1937, with 2.7 live trees per hectare and 3.5 dead trees 

per hectare retained from the preceding old growth. Woody debris 

included old decaying fallen trees (7 to 8 percent cover), stumps of 

old trees (48 per hectare), and abundant (3 percent cover) small trees 

killed by suppression or root rot. Understory cover was patchy and 

34 percent, dominated by salal. Canopy trees were 600 per hectare 

and 34 centimeters in diameter at 1.5 meter. Few shade-tolerant conifers were present. These plots were called legacy plots.

Experimental treatments included variable-density thinning to 

induce heterogeneity into tree canopies, underplanting with red alder, western white pine, grand fir, and western redcedar to restore 

lost tree species diversity, and decadence management for cavity 
218 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

trees to accelerate ecosystem development. Sampling grids were 

surveyed, and baseline data were collected in 1991 and 1992. Then, 

plots were treated by the landowner (Fort Lewis Military Reservation) and contractors with one of four randomly assigned treatments 

in spring, 1993: control; variable-density thinning with underplanting; dens for squirrels; and variable-density thinning combined with 

dens. In the first 5 years, supplementary dens had minor effects on 

flying squirrels (Carey 2002b). Relative density (RD) was used to determine how much to thin; RD is an index to intertree competition 

in even-aged evenly spaced stands of trees (Curtis 1982). For Douglas-fir, RD ranges from 0 to a biological maximum of 14; excessive 

crown restriction occurs with RD >7. Conventionally thinned timber 

plots had RD = 6.5 (biomass accumulation stage) and unthinned 

legacy plots had RD = 7.2 (emerging from competitive exclusion to 

biomass accumulation). An implementation team of research and 

management foresters randomly assigned RDs of 2, 4, and 6 to the 

cells and RD = 6 to the buffer of each variable-density thinning plot 

to achieve a 2:1 ratio of light (residual RD >4.75) to heavy thinning 

(RD <4.75) and a mean residual RD of 4.7 to 4.8. Plots treated with 

variable-density thinning were called mosaic plots.

Response variables were chosen from two perspectives. The first 

set of variables was drawn from the keystone complex symbolic of 

Pacific Northwest old growth (forests over 250 years old): northern 

spotted owl-northern flying squirrel-ectomycorrhizal fungi-Douglas-fir (Carey 2000a). The spotted owl is the flagship species for old 

growth and has been designated a threatened species by both federal 

and state governments. The flying squirrel is the primary prey of the 

owl. Hypogeous ectomycorrhizal fungal sporocarps are the primary 

food of the squirrel; the squirrels disperse the spores and associated micro-organisms (Li et al. 1986) throughout the forest. Mycorrhizal fungi enhance the ability of Douglas-fir to absorb water 

and nutrients from the soil and receive carbohydrates in return. The 

fungi move photosynthetic carbohydrates from trees to the mycorrhizosphere, providing support for a vast array of microbes, insects, 

nematodes, bacteria, and other soil organisms (Ingham and Molina 

1991). Aboveground, the food web expands laterally to include other 

raptors and mustelids; three species of squirrels; forest-floor small 

mammals; seeds, fruits, and fungal sporocarps; and various trees 

and shrubs. Thus, the complex provides a framework that is both 

functional and heuristic in evaluating forest ecosystem development 

in response to heterogeneity induced into canopies and to forest 

management generally (Carey et al. 1999c). The spotted owl and 

other predators, however, respond to ecosystems at the landscape 
A B

C H A P T E R 6 Ecological Foundations of Biodiversity 219

Figure 35—(A) A northern flying 

squirrel consumes a truffle. Photo by 

W. Colgan III. (B) A Douglas’ squirrel 

postures to defend its food source. 

Photo courtesy of American Mammal 

Society.

scale (Carey et al. 1992) and cannot be used to evaluate management at small scales. Thus, research focused on the abundances of 

three squirrels—the northern flying squirrel (fig. 35A), the Douglas’ 

squirrel (fig. 35B), and Townsend’s chipmunk—and compared their 

abundances to the simultaneously high abundances of all three species in complex old forest. The diets of the three species overlap, 

but the flying squirrel is a truffle specialist, the Douglas’ squirrel a 

conifer seed specialist, and Townsend’s chipmunk is a fruit generalist, feeding on seeds of conifers, seeds and nuts of deciduous trees, 

berries of shrubs, and truffles, but relegated to areas of high shrub 

cover in summer and hibernating belowground in winter. Thus, the 

combined biomass of these three species is a measure of ecological 

productivity—the reproductive fruits of the forest ecosystem and 

the capacity of the ecosystem to support diverse vertebrate predator 

assemblages (Carey et al. 1999c).

The second set of variables focused on forest-floor function, 

because it is the foundation for sustainability of forest ecosystems 

(Carey et al. 1996b). Mechanical operations, killing trees, and altering microclimate affect forest-floor function. A basic feature of most 

forest soils is dominance of biological activity by fungi, particularly 

ectomycorrhizal fungi. Variables included degree of dominance by 

fungi as measured by biomass ratios for total fungi to total bacteria, active fungi to active bacteria, and fungal-feeding nematodes 

to bacteria-feeding nematodes; biomass of predatory nematodes; 

and biomass and diversity of sporocarps of ectomycorrhizal Ascomycetes, Basidiomycetes, and Zygomycetes (hereafter referred to as 

truffles); diversity of epigeous fungi; and the coverage of fungal mats 

(Piloderma sp., Hysterangium sp., Gautieria sp.) (Carey et al. 1996b, 

Ingham and Molina 1991). Consideration of forest-floor function 
220 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

was extended hierarchically to litter invertebrates, abundance and 

diversity of vascular plants, and the integrity of the forest-floor small 

mammal community. This community, dominated by shrews, is particularly diverse in Pacific Northwest forests compared to the rest of 

the world (Carey and Harrington 2001, Carey and Johnson 1995). 

Because disruption of soil by mechanical operations and simplification of forest ecosystems by timber management can promote invasion by exotics (Halpern et al. 1999), exotic species were recorded 

and their tenure in the system tracted. Finally, resident birds play 

important roles in Pacific Northwest forests in regulating insect 

populations by insectivory and in decadence processes by excavating 

cavities in trees (Manuwal and Huff 1987). These birds are particularly sensitive to the simplifying effects of timber management on 

decadence and seed diversity. Thus, the diversity and abundance of 

birds in winter was measured (Carey 2003a).

Soil Food Webs and Forest-Floor Character

Both timber and legacy plots had fungal-dominated soils in terms 

of total-biomass and active-biomass ratios. Total fungal biomass in 

legacy plots, however, was almost three times greater than in timber 

plots. Fungal mats covered 66 percent of legacy plots compared to 

25 percent of timber plots. Abundances of fungal-feeding nematodes were similar. Bacteria-feeding nematodes in timber plots were 

1.5 times more abundant than in legacy plots. Predatory nematodes 

were most abundant in timber pots. Variable-density thinning 

had no effect on total biomass ratios but increased the dominance 

of fungi over bacteria in both timber mosaics and legacy mosaics. 

Total fungal biomass remained unchanged in timber mosaics but 

decreased in legacy mosaics. Fungal feeding nematodes decreased 

in timber mosaics but increased in legacy mosaics. Bacterial feeding nematodes and predatory nematodes increased with degree of 

disturbance within both types of mosaics. Truffle standing crop biomass averaged 0.5 kilogram per hectare but varied markedly (0 to 1.8

kilograms per hectare) seasonally in both timber and legacy plots. 

Of 28 species of truffles found in untreated forest, 19 species were in 

timber plots, with 7 of those species only in timber plots, and 21 species were in legacy plots, with 9 of them only in legacy plots. Rhizopogon was the dominant genus, with a relative frequency of 40 to 47

percent. Gautieria and Leucogaster were more frequent in legacy plots 

than in timber plots, and Melanogaster and Hysterangium were more 

frequent in timber plots. Truffle production was reduced in mosaics 
C H A P T E R 6 Ecological Foundations of Biodiversity 221

(from a frequency of 18 percent in control plots to 13 percent in variable-density thinning plots) in the short term with heavily thinned 

cells most reduced (to 10 percent). Truffle diversity increased to 48

species (versus 28 species in controls) and productivity quickly recovered. Gautieria and Hysterangium decreased in abundance in mosaics, but Melanogaster increased in species diversity and biomass. A 

total of 64 mushroom species were found prior to treatment, 37 (19

mycorrhizal) in legacy plots and 44 (15 mycorrhizal) in timber plots. 

Richness of ectomycorrhizal mushrooms was consistently highest 

in the legacy plots. After variable-density thinning, 108 mushroom 

species were found in legacy mosaics (versus 89 species in controls), 

and 78 species were found in timber mosaics (versus 65 in controls). 

Contrary to expectations, variable-density thinning did not significantly reduce the amounts of large coarse woody debris through 

mechanical destruction but did add small coarse woody debris in 

the form of logging slash and unmerchantable stems. Additional 

large coarse woody debris has been recruited in the form of diffuse 

root-rot mortality. The forest floor microclimate (temperature and 

moisture) increased in heterogeneity—mosaics maintained the array 

of moisture and temperature regimes that controls had but also developed some warm, some moist and warm, and some dry patches. 

Variable-density thinning produced increased patterning in litter 

invertebrate communities; all functional groups were maintained, 

but species dominating the functional groups now differ spatially 

in response to the induced heterogeneity that includes differences 

in new litter, added coarse woody debris, increased vascular plant 

cover, and soil disturbance as well as changes in light and moisture 

(Schowalter et al. 2003). 

Understory Plants

Legacy plots had 27 to 40 species of understory plants compared to 

49 to 87 species in the timber plots. Of 91 species found in timber 

plots, 51 species were not found in legacy stands, and 18 were nonnative species (1 tall shrub, 2 low shrubs, 13 herbs, and 2 grasses). Of 

47 species in legacy stands, four were not found in thinned stands, 

including the old-growth associate Pacific yew, and one was nonnative. Community structure differed with management history, with 

timber plots dominated by aggressive clonal native shrubs and ferns. 

Timber plots had greater cover for total understory (88 percent versus 34 percent), tall shrubs (12 percent versus 5 percent), salal (25

percent versus 13 percent), swordfern (16 percent versus 3 percent), 
222 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

and brackenfern (9 percent versus 2 percent). Mosaics initially had 

reduced understory cover and increased importance of 20 native 

and 11 exotic species. Two native species decreased in importance. 

Three years later, understory recovered, species richness increased 

by 150 percent, only four exotic species persisted in importance, and 

eight natives increased and seven natives decreased in importance. 

Underplanting has established root-rot-resistant trees in root-rot 

pockets that will restore canopy cover and increase the resilience 

of the forest and, in other heavily thinned areas, increase resistance 

to spread of root rot. Shade-tolerant trees are now established in 

patches throughout the plots and have the potential, with continued 

growth, to begin influencing understory patterning.

Small Mammals

Timber plots had 1.5 times the numbers and 1.7 times the biomass 

of small mammals of legacy plots, presumably because of their 

greater abundance and diversity of vascular plants. Keen’s mouse, 

a dominant species in natural forests, was rare in both forests. The 

Oregon creeping vole was inordinately abundant in timber (3rd

ranked) compared to legacy plots (7th ranked) and natural stands. 

The montane shrew was also inordinately abundant in timber plots 

(2nd ranked). Neither management produced communities typical 

of natural forests. After variable-density thinning, deer mice, Oregon creeping voles, and vagrant shrews increased in abundance in 

mosaics. No species decreased in abundance.

Squirrels

Northern flying squirrels were twice as abundant in legacy as in timber plots (1.0 per hectare versus 0.5 per hectare). Townsend’s chipmunks were the opposite (0.2 per hectare versus 0.8 per hectare). 

Douglas’ squirrels were low in abundance in both (0.1 per hectare). 

Flying squirrels decreased in abundance in legacy mosaics immediately following variable-density thinning (concomitantly with a decline in truffle production) but recovered within 5 years (along with 

truffle production). Chipmunks increased sharply in legacy mosaics 

following variable-density thinning and remained high. Douglas’ 

squirrels did not respond to variable-density thinning in the short 

term. It remains to be seen if flying squirrels and Douglas’ squirrels will increase over time as tree diversity increases and as trees 
C H A P T E R 6 Ecological Foundations of Biodiversity 223

increase photosynthetic activity and allocate additional carbon to 

seeds and ectomycorrhizal associates. California hazel and bigleaf 

maple are present and may begin producing high-quality nuts and 

seeds for the squirrels in response to the more open canopy and 

available light.

Wintering Birds

Species richness was higher in timber (16 species) than in legacy 

plots (12 species). Richness was unchanged in timber mosaics, ranging from 14 to 22 species 3 to 5 years after variable-density thinning. Richness varied annually but was consistently higher in legacy 

mosaics than in legacy controls in post variable-density thinning 

years 3 to 5 (12 to 16 species versus 10 to 16 species in controls). 

The proportion of stand area used increased in mosaics for two of 

eight abundant species (winter wren and song sparrow). No species 

used legacy controls more than thinned or mosaic stands. Cavityexcavating birds (Picidae) were present but low in abundance in all 

stands.

Implications

All stands maintained fungal-dominated soils, despite continued 

disturbance in the timber mosaics—three significant removals of 

subordinate and codominant trees over 20 years by commercial 

thinning. Mechanical disturbance associated with thinning, however, appeared to destroy near-surface fungal mats and promote Melanogaster over Hysterangium and Gautieria; the latter are more important foods to mycophagists. Induced heterogeneity nevertheless 

increased total sporocarp diversity. Sporocarp diversity rivaled that 

in old-growth forests around the region. Impacts of variable-density 

thinning on truffle production were brief. There is no clear, general 

effect of management on production of the sporocarps of hypogeous 

ectomycorrhizal fungi across the region other than effects on fungal 

mats (Carey et al. 2002). Retaining unthinned patches in mosaics 

might help conserve fungal mats.

Conventional thinning had produced rich understories dominated by clonal native species with numerous exotic species present 

in the timber plots. Legacy management had produced depauperate understories. Canopy mosaics markedly increased diversity and 

abundance of native species in both but only ephemerally increased 
224 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

A variety of trees—both living and 

dead—along with steep terrain 

and fog creates dramatic scenery in 

Olympic National Forest, near Forks, 

Washington. Photo by T. Wilson.

exotics. With underplanting, variable-density thinning is leading to 

increased spatial heterogeneity. Achlorophyllous mycotrophic plants 

were reduced in abundance in areas of dense understory; retaining 

small unthinned patches in mosaics would help conserve these species. 

Both conventional thinning and legacy management had produced imbalanced small mammal communities, with some species 

common in natural forests low in abundance. Inducing heterogeneity had immediate positive impacts on forest-floor mammals, 

but restoration of shade-tolerant midstories and development of 

midstory deciduous trees (e.g., bigleaf maple) will be required to 

restore biotic integrity. Chipmunks increased markedly in legacy 

mosaics with only brief declines in flying squirrels. Flying squirrels 

remained rare in previously thinned stands, perhaps owing to dense 

homogeneous understories that promoted excessively high and uniform chipmunk abundance. Similarly, variable-density thinning 

had positive effects on the winter birds and increased the overall 

habitat quality in mosaics. Bird communities, however, continued 

to have low abundances of cavity-excavating birds. Promoting deciduous trees (e.g., red alder) early in stand development provides 
C H A P T E R 6 Ecological Foundations of Biodiversity 225

short-lived trees for cavity excavation in the short term; decadence 

management may prove essential to maintaining cavity-excavating 

birds in managed forest.

In summary, this experiment has demonstrated that active, intentional management has potential in restoring and maintaining 

biological diversity in second-growth forests and in increasing the 

resilience of such forests to such disturbance agents as wind (larger 

more wind-firm trees), disease (resistance to spread of root rot), and 

insects (increased diversity and abundance of overwintering birds) 

without increasing potential for wildfire (forest floors remained 

moist; indeed, increased plant cover in the understory should generally produce moister and cooler conditions in the future). Increased diversity in the squirrel community and increased cover on 

the forest floor should reduce the potential for repetition of past 

severe predation by long-tailed weasels that decimated flying squirrel populations from time to time. Increased diversity of trees and 

shrubs bearing hard mast and increased production of hard mast 

should result in increased numbers and lower fluctuations in squirrel 

populations (all three species) as well. Inducing heterogeneity into 

homogeneous, closed canopies has positive effects on diverse biotic 

communities and ecosystem function as habitat even in the short 

term (5 years) in forests managed with conventional thinning for 

timber production and with legacy retention only. The rapidity of 

the growth of shade-tolerant trees in the understory will determine 

the rate at which heterogeneity continues to increase, and only time 

will tell if reduced elements of diversity (e.g., cavity trees, certain 

small mammals, and certain birds) will be restored; deciduous trees 

and shrubs are now well establish in the understory. 

Stochasticity, Disturbance, and Change

Resolving fear of environmental stochasticity (randomness), uncertainty, unpredictability, and change is aided by systems theory 

and an understanding of chaos theory and self-organizing systems. 

Bertalanffy proposed a self-integration (self-organization) model 

of hierarchical order with four related concepts of change (Regier 

1993): (1) progressive integration, or complexity, with parts dependent on the whole; (2) progressive differentiation, or parts becoming 

more specialized; (3) progressive mechanization, or limiting parts 

to a single function; and (4) progressive centralization, or certain 

parts dominate the system. This theory applies to organisms, societies, and ecosystems. Natural historians take self-organization as 
226 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

self-evident—their practical insights flow from comparative empiricism that is a synthesis of both perception and analytical understanding. Academic ecology, however, often consists of abstractions 

that are mobilized as “band-wagon” paradigms that may not be very 

pragmatic but may provide fruitful avenues of research to develop 

fundamental principles. 

Empirical observation asserts that biotic communities develop 

and succeed one another on stages set by environmental variables–

geographic location, landform, site characteristics, precipitation, and 

temperature (Clements 1936). Colonization by pioneers that grow 

rapidly and withstand physical extremes resets the stage for species replacement through competition. Biomass accumulates, internal regulation of biochemical and physical processes increases, 

variability is reduced, and a more-or-less stable climax condition 

results: equilibrium centered, with major disturbance exogenous. It 

is clear that there are communities that do this, for example, oldgrowth forests in the Pacific Northwest (Holling 1986). However, 

many biotic communities, including those in the Pacific Northwest, 

are subject to regular and irregular, minor and major, endogenous 

and exogenous disturbances at frequencies often in some way related to the lifespan of their longest lived or most persistent species, 

such that these species are adapted to the disturbance. For example, 

the foliage of fire-adapted species is significantly more combustible 

than related species in communities not subject to frequent fires. 

Theoretically, most species can be described on a continuum 

from r-strategists (opportunists selected for maximizing returns in 

unpredictable-unstable environments) to K-strategists (equilibrium 

species selected for efficiency of foraging in predictable-somewhat 

stable environments) (MacArthur and Wilson 1967). K is the symbol for equilibrium carrying capacity in population models, and r is 

the intrinsic rate of increase in populations. K-strategists tend to be 

larger in size and have lower reproductive potential, longer lifespans, 

less dispersal ability, and more competitive ability than r-selected 

species. Ecosystems also have strategies for development; in other 

words, they are self-organizing but regulated by physical, chemical, 

and biological processes (Odum 1969). The r and K concepts can be 

used to describe ecosystem functions, for example, exploitation and 

conservation (Holling 1986) (table 20). Early-seral stages emphasize exploitive processes (binding nutrients, rapid accumulation of 

biomass, and modification of the environment). Later-seral stages 

emphasize increased organization through trophic and competitive 

interactions (cooperation and coadaptation) that reduce variability 

and, if uninterrupted long enough, reduce diversity. 
Table 20—Pianka’s (1970) correlates of r- and K-selectiona

Feature r-selection K-selection

Climate Variable and/or unpredictable Fairly constant and/or predictable

Mortality Often catastrophic, nondirected, densityindependentMore directed, density dependent

Survivorship Often Type III Deevey survivorship curves Usually Type I or II Deevey survivorship 

curves

Population size Variable in time, nonequilibrium Fairly constant, equilibrium

Intra- and interspecific competitionVariable, often lax Usually keen

Relative abundance Often does not fit broken stick model Usually fits broken stick model

Favored by selection  Rapid developement

 High rmax

 Early reproduction

 Small body size

 Semelparity

 Slow development, greater competitive 

ability

 Lower resource thresholds

 Delayed reproduction

 Small body size

 Iteroparity

Length of life Short Long

Leads to... Productivity Efficiency

a The theory of r- and K-selection for life history evolution dominated demographic thinking in the 1960s and 1970s, 

became archaic in the 1980s, and now has arisen anew to incorporate density-dependent population regulation, resource availability, environmental fluctuation, and predation risk. 

Source: Reznick et al. 2002

C H A P T E R 6 Ecological Foundations of Biodiversity 227

Hierarchy Theory

Forces of change operate at different scales. Within a given multivariate space, regions of stability expand, contract, and disappear 

over time in response to changes in slow variables (such as tree 

growth, fuel accumulation, and increasing herbivore populations). 

Abrupt change occurs because multiple stable states emerge as slow 

variables change. Jumps between stability domains may be triggered 

by exogenous disturbances. External events may lead to highly repetitive consequences by reinitiating ecosystem development. Variability, then, produces diversity as a consequence of cyclic shifting of 

competitive advantages among species within and among different 

scales. Thus, change is an internal property of each system, gradual 

for long periods followed by inevitable jump events. 

Hierarchy theory provides useful stability and resilience 

c­oncepts:

 There can be more than one stability region; multiple equilibria 

are possible.
228 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

 Behavior is discontinuous when elements of a system move from 

one stability domain to another because they become attracted.

 Precise kind of equilibrium (steady state or stable oscillation) is 

less important than the fact of equilibrium.

 Parameters of the system that define the existence, shape, and 

size of stability domains depend on a balance of forces that may 

shift in patterns of variability in space and time; managerially 

reduced variability is likely to lead to smaller stability regions 

whose contraction can lead to sharp changes.

Stability emphasizes equilibrium, low variability, and resistance 

to and absorption of change. Resilience emphasizes the boundaries 

of stability domains and events far from equilibrium, high variability, and adaptation to change (the school of linear interactions, however, treats resilience in an opposite fashion—how fast the variables 

return toward their equilibrium following a perturbation). Holling 

(2001) developed this theory further into Panarachy.

Panarchy Theory

Ecology has always been concerned with stability—whether natural 

systems have developed sufficient resilience or stability to absorb 

increasing human populations and demands for food, fiber, and aesthetic needs (Holling 1969). The concept of a global biochemical 

homeostasis—that life keeps the atmosphere optimal for the contemporary biosphere—provides a global rationale for rehabilitation, 

protection of ecosystems, and land-use management (Holling 1986). 

Global homeostasis prompts questions: How do ecosystems absorb, 

buffer, or generate change? Why are we surprised when causes, behaviors, and results sharply differ from what we expected? In answer to the latter, our expectations develop from interactions of the 

metaphors we use to provide understanding and our perceptions of 

memorable events, both of which are incomplete. Three influential 

metaphors are (1) nature as equilibrium, (2) nature engineered with 

multiple equilibria, and (3) nature evolving.

Equilibrium emphasizes constancy in time, spatial homogeneity, linear causation, and images of a benign nature wherein management mistakes can be made, but recovery is assured, for example, 

the traditional production forestry paradigm (Barrett 1962, Smith 

1962). Multiple equilibria suggest a more dynamic system, with 

spatial heterogeneity and nonlinear causation. Two different beliefs 

arise from multiple equilibria: (1) landscapes are fixed or we have 
C H A P T E R 6 Ecological Foundations of Biodiversity 229

sufficient knowledge to keep them fixed, and (2) key features are 

maintained by variability itself and by maintaining the configuration 

(structure) of a system. In other words, structure-based management 

can maintain multiple equilibria. This is the unspoken underlying 

paradigm for conservation biology with its reserves and management for the range in natural variation (e.g., Hunter 1999). 

Evolutionary change suggests generative, competitive, and behavioral processes maintain the characteristics of the system. When 

variability changes, parameter values shift, landscapes change, stability domains shift, key variables become more homogeneous, and 

perturbation can no longer be absorbed. When control is internal 

and self-regulated, organizational change may occur. When control 

is external and continuing control requires ever-increasing vigilance, 

pathologies may develop. Thus, progressive evolution requires not 

only function but also organization (food webs and trophic relations). The complexity of systems emerges not from random assemblage of numerous controlling processes but from self-organizing 

systems and a small set of critical processes that create and maintain 

the self-organization (Holling 2001). Diversity and individuality of 

components, localized interactions among components, and an independent process that uses the outcomes of local interactions to 

select components for enhancement are characteristics of complex, 

adaptive systems. Pragmatic sustainability has to do with the set 

of critical self-organized variables and their transformation during 

system development. There is simplicity behind complexity that can 

be understood and communicated lucidly. This is known as adequate 

integrative theory—as simple as possible, but not simple; dynamic 

and prescriptive, but not static and descriptive; embracing uncertainty and unpredictability (Holling 2001). This paradigm underlies intentional systems management for conservation of biodiversity, where biodiversity includes the variety of taxa (genes, species, 

populations), organization (communities, ecosystems, life zones, biomes), processes (evolutionary, ecological, managerial), and products 

(goods, services, experiences) (Carey et al. 1999c). 

Hierarchies and adaptive cycles comprise the basis of socioecological systems across scales (Holling 2001). Panarchy is the hierarchical structure in which socioecological systems are interlinked 

in never-ending adaptive cycles of growth, accumulation, restructuring, and renewal. Panarchy theory is a model of complex system behavior that describes how a healthy system can invent and 

experiment, benefiting from invention that produces opportunities, while being safeguarded from those that destabilize because 

of their nature or excessive exuberance. Space-time hierarchies are 
230 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

semiautonomous rather than top-down authoritative structures. 

Their levels are formed from the interaction of elements with shared 

speed and spatial attributes. Each level operates at its own pace, and 

each communicates a small set of information to the next higher, 

slower, and coarser level. Slower and larger levels set the conditions 

within which faster and smaller ones function. Thus, the forest moderates the climate for individual trees. The levels of a dynamic hierarchy serve two functions: (1) conserve and stabilize conditions for 

the faster and smaller levels and (2) generate and test innovations 

by experiments occurring within a level. Examples of hierarchies in 

space and time are (1) breeze, thunderstorm, front, long wave, El 

Niño, and climate change; and (2) needle, crown, patch, stand, forest, and landscape. A time-population size hierarchy is individual, 

small group, contract, policy, law, constitution, and culture. Another 

is fad, values, and traditions.

The adaptive cycle (fig. 36) transforms hierarchies from fixed, 

static structures to dynamic, adaptive entities whose levels are sensitive to small disturbances at the transition from reorganization 

to rapid growth. Three properties shape the adaptive cycle and the 

future state of a system: (1) inherent potential that is available for 

change; this potential determines the possible range of future options and can be considered the wealth of the system; (2) internal controllability or the degree of connectedness between internal 

variables and processes; the degree of flexibility of the system; and 

the degree to which it can control its own destiny; and (3) adaptive capacity or resilience, a measure of vulnerability to unexpected, 

unpredictable shocks. Wealth, connectedness, and adaptive capacity 

are general properties from the scale of a cell to the biosphere. In the 

adaptive cycle, the trajectory alternates between long periods of slow 

accumulation and transformation of resources (from exploitation to 

conservation, r to K) with shorter periods that create opportunities 

for innovation (from release to reorganization, Ω to α) (fig. 36).

Ecosystem dynamics consist of not only the two functions 

(exploitation and conservation) that determine succession and development but also creative destruction functions that result from 

increasing strength of connections in maturing ecosystems that 

can result in abrupt change. Conservation leads to wealth and becomes an accident waiting to happen—a buildup of stored energy 

that either is dissipated by local internal disturbance leading to increased complexity or released by wind, fire, disease, or insect outbreaks. When timing is set by the slowest variable (e.g., growth of a 

dominant Douglas-fir cohort), forces of change can lead to intense, 

widespread mortality (e.g., catastrophic fire or epidemic disease). 
Reorganization

Conservation

Connectedness

Potential

Exploitation

Release

C H A P T E R 6 Ecological Foundations of Biodiversity 231

Figure 36—The adaptive cycle of 

self-organizing systems (adapted from 

Holling 1986, 2001). Ecosystems may 

have four primary functions (r, exploitation; K, conservation; Ω, release; α, 

reorganization), here arrayed in a twodimensional space of stored resources 

potentially available (e.g., accumulated 

biomass, Y-axis) and connectedness 

(sensitivity to perturbation, X-axis). As 

plants exploit a newly cleared forest, 

the ecosystem moves rapidly to accumulation of biomass (conservation), 

and the stored potential of the system 

becomes great and connectedness is 

high. High connectedness increases 

susceptibility to perturbation. Minor 

perturbations release some of the 

stored potential for niche diversification and reorganization of the system 

into a more complex, less connected 

structure with high potential. Catastrophes can release most or all of the 

potential and return the system to exploitation. With legacies, exploitation 

(r) can move rapidly to conservation 

(K); without legacies, exploitation may 

last longer with low connectedness 

and low potential.

Individuals constituting slow variables eventually senesce and die, 

but their impacts are local and not synchronous. When timing is set 

by the fastest variable, changes are less intense, and spatial impacts, 

although synchronous over large areas, are patchier. These functions 

are called creative destruction even though organisms are destroyed, 

because their success in competition, appropriation of resources, and 

accumulation of biomass results in a release of tightly held resources 

promulgating the fourth function, creative renewal (e.g., ecosystem 

reorganization). Rapid cycling produces patchy ecosystems; slow 

cycling can produce waves across space (e.g., spruce budworm outbreaks). Things can go awry, however, during renewal. Savannahs 

can become dominated by woody shrubs because of loss of capacity 

for water retention. Burning can shift forest vegetation to bogs and 

eventually peat lands. Clearing tropical forests can produce scrub 

savannahs. The degree of resilience of a system is determined by 

the balance between the processes of mobilization (freeing resources 

for other uses) and retention (e.g., of biological legacies, including 

coarse woody debris and living plants).

It has long been argued that more species and more interactions confer more stability to biotic communities. The argument is 

that the more pathways available for movement of energy and nutrients, the less the effect of removing one pathway. Although May 

(1973) showed that increasing the diversity of randomly connected 

networks actually decreased stability, ecosystems are not randomly 

connected (Holling 1986, May 1973). Ecosystems have a hierarchical structure in space, time, and speed of variables. Thus, the relevant 

measures of species diversity, which is one measure of complexity, 

should not involve all species but only those contributing to physical 
232 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

structure and dynamics. The most significant measure of complexity 

concerns the degree of connectedness within ecosystems. Extensive 

land clearing to produce monocultures produces high connectedness 

through pest loads and little resistance. In other words, the pattern 

of connectedness and the resultant balance between stability and 

resilience are a consequence of the pattern of external variability the 

system has experienced. In the Tropics, consistent temperature and 

precipitation produce highly stable forests of low resilience, sensitive 

to disturbance by humans, and characterized by high species diversity. Temperate systems have high climatic variability, low stability, 

and high resilience, resistant to disturbance by humans. Hierarchical 

systems are not static in kinds or strengths of connection that determine resilience. Succession introduces connectedness. Overconnectedness produces discontinuous change, increases variability, and 

leads to resilience. Underconnectedness leads to collapse of resilience, especially during the destabilized part of the cycle, especially 

if mobilization is not balanced by retention. Forest ecosystem development disrupts overconnectedness through fine-scale patchiness 

and promotion of tree species diversity and balances mobilization 

by intermediate and fine-scale disturbances with biomass accumulation in dominant trees, retention of coarse woody debris on the forest floor, and accumulating slowly decaying organic matter into the 

soil (Carey et al. 1999b). Thus, adaptive cycles embrace opposites—

growth and stability versus change and variety (Holling 2001). The 

spatial and temporal patterns generated by the four major ecosystem 

functions (exploitation, conservation, creative destruction, renewal) 

determine the qualitative structure of the ecosystem. The resultant 

architecture of the ecosystem provides a variety of niches occupied 

by different species.

General sustainability suggests a complexity that can overwhelm understanding. At best, efforts to manage ecosystems are 

experiments testing a general hypothesis of stability and resilience. 

Management to reduce variability represents an equilibrium-centered view of constant nature. It achieves short-term objectives, 

but eventually the system evolves into a qualitatively different system—the biophysical environment becomes more fragile and more 

dependent on vigilance and error-free management. Reduced variability produces reduced resiliency and spatial homogenization produces increased connectedness; the result is surprises. The implications for management are (1) ecosystems have a natural rhythm of 

change; restricting temporally and homogenizing spatially produces 

surprises (e.g., Swiss needle cast); (2) developing predictive tools 

should have a lower priority than designing systems that are flexible 
C H A P T E R 6 Ecological Foundations of Biodiversity 233

enough to undergo renewal after unexpected events. Holling (2001) 

summarized the current understanding of panarchies (see sidenote 

33). It appears that spatial contagion and biotic legacies generate 

self-organized patterns over scales in space and time (Carey et al. 

1999b, 1999c).

C H A P T E R 7

From Ecology to Forest Management

How does one move from understanding various ecological processes underlying biological diversity and ecological resilience to 

pragmatic methods for managing second-growth forests for economic, ecologic, and social values? How does one actively and intentionally manage for multiple values? The problems seem enormous: 

forestry seems to lack an adequate scientific basis (Perry 1998), and 

ecology seems to lack an accepted theoretical framework derived 

from first principles (Belovsky et al. 2004) (sidenote 34). Furthermore, predicting system behavior is difficult because it depends on 

numerous variables and their interactions (20 components provide 

countless potential interactions) and causes and effects are difficult 

to demonstrate, yet emergence of new structure and function seems 

essential (Schneider and Kay 1994). The solution to conserving nature may be to stop managing for fixed idealized states, to begin 

appreciating that complex systems emerge from the interaction 

of biological entities with each other and the environment, and to 

change our focus from biodiversity to biocomplexity, the defining 

property of all ecosystems (Dale et al. 2000, Dybas 2001, Holling 

1992, Schneider and Kay 1994) (sidenotes 35, 36). Finally, we must 

recognize that temperate zone forests in the Northern and Southern 

Hemispheres (one-fourth of the world’s forests), are mosaics shaped 

by fire (fig. 37), wind, herbivory, other natural disturbances, and, 
236 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 34—Ten fundamental problems in ecology 

(Belovsky et al. 2004):

 Ecology is faddish—issues 

come and go without resolution.

 Ecologists exhibit poor 

scholarship, ignoring the past 

literature (and literature from 

allied fields).

 Integration of empirical and 

theoretical ecology is inadequate.

 Integration of natural history 

and experimentation is inadequate.

 There is implicit belief in 

single causes despite evidence 

for multiple causation.

 Application of equilibrial and 

disequilibrial perspectives are 

often misguided.

 Ecological studies are inadequate in replication in space 

and time.

 Data collection lacks rigor, 

which hinders comparison of 

studies.

 Forces driving studies are 

often methods or statistics, not 

questions.

 Basic ecology is often conducted as distinct from applied 

ecology.

Figure 37—Natural regeneration begins to show itself among the 

snags left by a large-scale fire in the 

Wallowa-Whitman National Forest in 

northeast Oregon. Photo by T. Wilson.

increasingly, human activities including fire suppression, logging, 

grazing, and fossil fuel consumption (Frelich 2002).

In forest ecology, three fundamental practices for managing 

second-growth forests for multiple values are (1) retention and protection of biological legacies during and after harvests of timber 

(sidenote 37); (2) long rotation times between major harvests (sidenote 38); and, in the interim, (3) active creation of biocomplexity 

in managed forests (Carey 2003a, Franklin et al. 2002) (sidenote 

39). Legacy retention addresses problems of dispersal-limited species like lichens, and jumpstarts the development of biocomplexity 

during reorganization. A significant amount of time is required for 

forests to accumulate biomass and develop a complex structure at 

multiple scales. Active creation of biocomplexity with a variety of 

manipulations prevents competitive exclusion and a persistent state 

of low diversity and limited function. 

In fire-adapted forests, management of fuels and diseases with 

mechanical treatments, grazing, and prescribed fire is also fundamental but complex (Tiedemann and Woodard 2002, Wright and 

Agee 2004). All AIM practices include management of disturbances 

of varying intensity and frequency. All species have evolved in the 

presence of disturbance and, in a sense, are matched to recurrent 

patterns of disturbance (Frelich 2002, Paine et al. 1998, Tausch et 

al. 1993). In this context, full intentionality must be brought to the 

patterns of disturbance that should be induced and that will occur 

spontaneously as well as to operations, including consideration of 
C H A P T E R 7 From Ecology to Forest Management 237

Sidenote 35—Guidelines for 

ecosystem management (Schneider and Kay 1994):

 Maintain a hierarchical perspective with careful attention 

to scale and extent.

 Examine the spatial, temporal, 

thermodynamic, and informational aspects (dynamics).

 Recognize that system 

behavior is emergent and 

catastrophic—dynamic with a 

degree of unpredictability and 

with phases of rapid change.

 Accept that ecosystem selforganization unfolds like a 

symphony—one needs to understand the rules of composition.

 Accept that living systems are 

self-organizing and will look 

after themselves—the challenge is to learn to work with 

these self-organizing processes to meet our needs while 

preserving the integrity of the 

system.

 Accept that one must not destroy, but rather must maintain 

the biodiversity needed for the 

regeneration processes.

purposes, risks, experience, and engineering and geological methodology in the design and management of logging systems and transportation systems. Situations in which risks of environmental damage owing to logging and transportation systems cannot be reduced 

to an acceptable level (a background disturbance level) will preclude 

AIM with silviculture. In addition, AIM for biocomplexity may entail 

restoring lost diversity (planting, underplanting, and seeding) and 

removing exotic species. In western Washington, common exotics 

with potential to seriously modify forests include English ivy, English holly, and, along roads and in clearings, scotchbroom. Costs and 

economic returns of various AIM techniques are often cited as reasons for doing some and not doing others; but poor (partial) AIM is 

unlikely to hit the target (fig. 38). 

Given the potential for purposeful manipulation of ecological processes and unintentional interference with other ecological 

processes throughout the life of a forest, understanding variability 

in how temperate and boreal forests develop is necessary for developing pragmatic management systems and avoiding unintended 

consequences (Frelich 2002). Variation is a genuine property of 

ecological systems that includes variation in space and in time in 

processes that generate the patterns we observe (Benedetti-Cecchi 

2003). This conception of variation is much different than the range 

in natural variation in patterns that has attracted so much attention; 

those patterns are the result of multiple processes and stochastic 

events. Although there is a lack of coherent theory linking variation in processes to variation in responses of organisms and systems 

(patterns), one must grasp and use the processes by which biotic 

communities organize themselves and understand how the relative 

influence of each process varies from place to place and time to time 

with changes in the biophysical environment, including disturbance 

regime and regional species pool. Thus, key questions are: How 

much variance is found in the relative importance of basic processes? What are the adaptations in pragmatic management that must 

follow as one moves from one physiographic province to another 

or from one forest type to another within the same physiographic 

province? What are the relationships among the processes that produce complex forest structure and biological diversity and that lead 

to healthy, resilient ecosystems? To what degree can forest development be guided managerially? To what degree will unhindered and 

unaided self-organization of forest ecosystems, after destruction of 

forests by logging, grazing, agricultural clearing, and fire exclusion, 

produce the materials and services we value for ourselves and for 

other forms of life?
238 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 38—A marksmanship 

analogy: that’s the point of intentionality—AIM carefully, or not at all. 

In a marksmanship analogy, it is not 

sufficient to chamber a cartridge and 

pull the trigger. Target identification, 

a clear field of view, a safe backdrop, 

knowledge of ballistics and trajectory, estimation of distance and wind, 

matching of rifle and cartridge to 

purpose, careful matching of stock to 

cheek and shoulder, alignment of rear 

sight with front sight, careful breathing, and gently squeezing the trigger, 

are all necessary for high marksmanship. The marksmen-practitioners will 

be familiar with all the details of technique. Other practitioners and observers are essential to spotting and target 

identification (interdisciplinary /collaborative management teams), safety 

(range officer/regulatory agencies), and 

choosing experts and sharpshooters 

to support and withdrawing support 

from the “plinkers” shooting beer cans 

in a quarry (all stakeholders). Graphic 

by A. Wilson; photo by A. Carey.

Structure, Pattern, and Process

Much literature exists on the structure of forests, the composition 

of forest communities, the processes influencing their development, 

and the patterns of biotic communities imposed on the landscapes 

by natural and anthropogenic disturbance regimes, particularly for 

western North America (sidenote 40). A large reading list could 

also be constructed just on disturbance and resulting patterns in and 

of biotic communities (Frelich 2002, Korpilahti and Kuuluvainen 

2002, Pickett and White 1985b). Much of the disturbance literature addresses landscape dynamics, fragmentation, and design of 

reserves and corridors. There is also extensive literature available on 

silvics (Burns and Honkala 1990a, 1990b) and silvicultural systems 

and techniques (Barrett 1962, Burns 1983, Curtis et al. 1998, Kohm 

and Franklin 1997, Nyland 2001, Smith 1962), especially for timber 

management.

Synthesis

A major impediment to achieving synthesis and consensus on how 

to address the challenge of conservation of nature in managed forest 

ecosystems lies in deeply rooted ecological philosophies related to 
C H A P T E R 7 From Ecology to Forest Management 239

Sidenote 36—Guidelines for 

landscape management (Dale et 

al. 2000):

 Examine impacts of local decisions in a regional context.

 Plan for the long term and the 

unexpected.

 Preserve rare landscape 

elements and their associated 

species.

 Avoid uses that deplete natural 

resources.

 Retain large contiguous or 

connected areas of complex 

forest.

 Minimize the introduction 

and spread of exotic species.

 Avoid or compensate for the 

effect of human development 

on ecological processes.

 Implement management 

compatible with the natural 

potential.

concepts of equilibria, stability, succession, development, and alternative stable states. Frelich (2002) suggested many “false” arguments 

ensue over these concepts as a result of narrow perspectives on the 

part of the antagonists. He posited that questions of scale and differences in spatiotemporal perspective underlie arguments over these 

concepts. For example, stability is a function of the length of time 

of observation and size of area observed. He suggested that interactions of neighborhoods, cumulative disturbance severities, and degree of dominance by late-seral species produce four categories of 

landscape dynamics that affect stability in species composition and 

in age structure over time and space and how and whether succession or development takes place (table 21). 

Neighborhoods are small groups of trees (10 to 20 meters across) 

that exist within larger forest communities at the scale of tree-fall 

gaps, spot fires, and root-rot pockets—a scale of about 50 square 

meters or about 100 neighborhoods per 0.5 hectare; a 0.5-hectare area, then, may have over 50 patches of significant disturbance 

(gaps owing to the death of more than two trees). Differentiation 

of patches also reflects differences in soil and substrates, climatic 

variation owing to elevation, patterns of invasion by tree species, and 

positive neighborhood effects when two species or species groups 

grow together. These complex effects can produce distinctive patches 

of understory-midstory vegetation at the scale of 0.1 to 0.5 hectare 

(Carey et al. 1999b). Frelich (2002) suggested that if some relative 

stability in age structure is to be maintained, the minimum area occupied by a forest community should be 50 times the patch size—or 

more than 5 to 25 hectares, sizes coincidently and commonly dictated by complex topography (Carey and Peeler 1995). The minimum landscape required to absorb infrequent severe disturbances 

of less than 2,000 hectares might be 15,000 hectares or more, with 

no single disturbance occupying more than 20 percent of the area in 

a 250-year period for temperate deciduous-conifer forests. Induced 

disturbance regimes (say variable-retention harvesting of 25-hectare biotic communities on variable rotations averaging 100 years) 

also requires landscapes of 15,000 hectares or more to maintain a 

shifting-steady-state mosaic on a decadal basis (Carey et al. 1999c). 

Frelich (2002) referred to “punctuation times” for disturbances that 

maintain quasi-equilibria in age structure and composition in large 

landscapes; disturbances of 0.1 to 0.5 hectare can take place on the 

scale of decades, 10 to 100 hectares on the order of 0.5 to 10 centuries, and 1,000–10,000 hectares on the order of millennia (fig. 39).

Neighborhood effects are widespread and important forces operating in forests. In general, neighborhood effects are the ways in 
0.1 10 100 1,000 10,000

1

10

100

1,000

10,000

Neighborhood

Stand

Large stand

Small landscape

Large landscape

Forest size (hectares)

Punctuation interval (years)

240 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 37—Biological 

legacies are diverse:

 Large, old, live conifers with 

their unique architecture and 

epiphytic plants, decay organisms, and ectomycorrhizal 

fungal associates

 Large, old, live deciduous trees 

with their unique architecture, 

epiphytic associates, decay 

organisms, and mycorrhizal 

symbionts

 Large, dead, standing trees and 

their associates and inhabitants

 Large, fallen trees on the 

ground and in streams with 

their associated biotic communities

 Intact patches of forest floor 

with their associated flora, 

fauna, seedbanks, and advance 

regeneration

 Intact patches of forest, 

including trees, epiphytes, 

understory, litter, humus, soil 

seedbanks, and soil food webs

 The biotic communities associated with intact headwater 

seeps, streams, and other 

wetlands

 The biotic communities associated with various intact physical landscape elements such 

as rock outcrops, talus slopes, 

balds, and special soil types

Figure 39—Frequency of disturbance events that disrupt age structure 

for a variety of forest sizes in Upper 

Michigan’s hemlock-hardwood forest 

(adapted from Frelich 2002).

which trees alter their immediate surroundings. A more formal definition is:

Any process mediated by canopy trees that affects the replacement probability by the same or other species at the 

time of canopy mortality. Neighborhood effects are defined 

in relation to dominant tree species or groups of species. 

Positive neighborhood effects (analogous to feedback effects) are processes that promote self-replacement; negative 

effects are processes that deter self-replacement (unless no 

other species are available); and neutral effects are processes 

that neither favor nor disfavor self-replacement (Frelich 

2002). 

For example, as the canopy of a Douglas-fir-dominated forest grows 

and closes, death of a Douglas-fir favors replacement by shadetolerant species such as western hemlock, if seeds or seedlings are 

present—a negative neighborhood effect for Douglas-fir. But death 

of a large, dominant western hemlock also favors western hemlock—a positive neighborhood effect for hemlock. There are two 

types of neighborhood effects: (1) overstory-understory effects, positive or negative, that influence the species composition of seedlings 

and saplings by shading, litter character, stump sprouting, and seed 

rain; and (2) disturbance-activated effects, operating mainly in forests perpetuated by intense fire, where seedlings are killed along 

with canopy trees and new regeneration is due to serotinous seed 

rain (jack pine, lodgepole pine) or sprouting from underground 
Table 21—Four categories of landscape dynamics in temperate evergreen-deciduous forests with reference to 

correspondence in some forest types of western North America

Category A—Positive neighborhood effects and low-severity disturbance:

	Adjacent stands differ in composition owing to species interactions.

	Low- to moderate-severity disturbances produce different-aged patches at the neighborhood, stand, and landscape scales.

	Stability of age structure is low in the neighborhood, moderate in stands, and high in landscapes.

	Composition stability is high in neighborhoods, stands, and landscapes.

	High-severity disturbance is rare and destabilizes composition.

	Landscape consists of a matrix of late-succcessonal species, all-aged neighborhoods, and stands with a few standsize inclusions of even-aged early-seral species.

	Examples: western hemlock-sitka spruce in Washington, British Columbia, and Alaska and hemlock-hardwoods 

in eastern North America

Category B—Positive neighborhood effects and high-severity disturbance:

	Patches on uniform soils owing to species interactions.

	Low- to moderate-severity disturbance plays a minor role.

	High-severity disturbance is common and stabilizes composition in the neighborhood, stand, and landscape.

	Stable age structure is rare in neighborhoods and stands but may occur on large landscapes.

	Successional episodes proceed during periods without crown fire.

	Landscape is a matrix of large complex-shaped stands of even-aged early-seral species with a few small standsize inclusions of uneven-aged late-seral species.

	Examples: lodgepole pine in Yellowstone National Park and Alberta, Canada, and near-boreal jack pine

Category C—No or negative neighborhood effects and low-severity disturbance:

	Patches of different composition and different age caused by tree-fall gaps and other small disturbances.

	Composition stability is low among neighborhoods, moderate to high in stands and landscapes.

	Severe disturbance is rare and destabilizes composition in neighborhoods, stands, and landscapes.

	Successional episodes are initiated by moderate- to high-severity disturbance.

	Landscape matrix is a fine-grained (neighborhood-scale) mosaic of late-seral species with stand-scale inclusions 

of even-aged early-seral species.

	Examples: red spruce, white spruce, and paper birch in the Northeastern United States; spruce, fir, birch, and 

cedar in Minnesota; and Douglas-fir, western hemlock, and western redcedar in the Pacific Northwest

Category D—No or negative neighborhood effects and moderate- to high-severity disturbance:

	Patches of different composition caused by any disturbance.

	Disturbance perpetuates instability of species composition; compositional stability is low among neighborhoods 

and stands, but differs in landscape.

	Stability of age structure is low among neighborhoods and stands but may be high in landscapes

	Successional episodes initiated by disturbance of any severity.

	Landscape matrix of large complex even-aged stands of mixed early- and mid-seral species with stand-scale 

inclusions of older forests.

	Examples: white pine, red maple, and northern red oak forests in eastern North America and Oregon white oakfir-wetlands mosaics in the Puget Trough in Washington

Source: Frelich 2002.

C H A P T E R 7 From Ecology to Forest Management 241

root stocks (aspen). Disturbance effects, however, will also result 

from species adaptations to colonization and dispersal. In the Pacific Northwest, disturbance gaps may be colonized by wind-blown 

western hemlock seeds (from kilometers away) and bird-transported 
242 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 38—What is a long 

rotation?

 Certainly one that meets or 

exceeds the culmination of 

mean annual increment of tree 

diameter growth—say a minimum of 100 years in Douglasfir forests.

 It differs with forest type, type 

of land ownership and associated goals—for example, for 

Douglas-fir forests, 100 years 

(industrial forest), 100 to 150

years (state trust lands), and 

150 to 350 years (federal multiple-use lands), and a maximum that is indeterminate 

(late-successional reserves).

 Not a goal with uneven-age 

management or when no final 

harvest is planned.

Pacific madrone seeds as well. Conifers and hardwoods often have 

contrasting neighborhood effects, favoring their own reproduction 

and reducing the success of the other. Neighborhood affects nutrient availability, light characteristics, duff and coarse woody debris 

characteristics, and differential biota (such as mycorrhizae) in the 

forest floor in conifer and hardwood forests. Combined with disturbance regimes, neighborhood effects influence stabilities at the 

neighborhood, stand, and landscape levels. Landscape categories A

and C may produce shifting-steady mosaics. Category A produces 

a self-perpetuating quasi-climax similar to those described by Clements (1936). Category B produces nonclimax forests of jack pine, 

red pine, or lodgepole pine. Category C may produce development 

of complex forests with development reset by infrequent severe disturbance—Douglas-fir can persist in the canopy in significant numbers for over 750 years. This longevity is particularly striking in the 

context of global climate change wherein most forests in the United 

States developed during interglacial periods that allowed maximum 

periods of development of a particular forest type of only 1,000 to 

5,000 years (Frelich 2002). Category D resembles the individualistic 

successional model with no stable endpoint. Rather than focus on 

succession, Frelich (2002) suggested thinking of vegetation growth 

stages that integrate development (structural changes) and successional (compositional) changes over time; the concept of envelopment over time, mentioned earlier, may be more appropriate. Ecosystem development stages (see table 17) incorporate concepts of 

alternative stable states and developmental processes that may avoid 

or skip particular stages, and the possibility of regression to earlier 

stages in the absence of disturbance. In any case, severe disturbance 

always initiates a new sequence of development (envelopment) but 

not always a new successional sequence. Frelich (2002) proposed a 

cusp-catastrophe model (fig. 40) that also allows alternative stable 

states, regression, jumps, and surprises, with possibilities for instability and hysteresis, and that predicts development as a consequence 

of the interaction neighborhood effects, cumulative disturbance severity, and degree of dominance by late-seral species.

To further clarify differences among succession, development, 

and envelopment, succession is defined as “a directional change in 

species composition over time, where one species group replaces another” (Frelich 2002). Changes in composition of lesser magnitude 

than complete replacement are called “fluctuations”—changes in 

the relative proportions of two or more species. Thus, development 

sometimes is accompanied by succession, but often it is not. At least 

five models of succession are extant (Frelich 2002). The cyclic model 
Neighborhood effects

Cumulative disturbance severity

+

—

0

High

Low

High Moderate Low

Dominance by latesuccessional species

Discontinuous changes up or down at 

cusp when cumulative disturbance 

severity crosses cusp

Unstable forests

Continuous compositional change 

as cumulative disturbance 

severity changes

Compositional stability 

at moderate- to highseverity disturbance 

(stable forests)

Compositional stabllity at 

low- to moderate-severity 

disturbance (stable forests)

Crown fire Heavy

windthrow

Surface

fire

Treefall

gaps

C H A P T E R 7 From Ecology to Forest Management 243

Figure 40—General form of the 

cusp-catastrophe model, showing how 

changing disturbance severity affects 

the composition of stands dominated 

by species with negative, neutral, and 

positive neighborhood effects (Frelich 

2002).

is A  B  C ...  A, and has been attributed to Watt (1947). An 

example is an aspen forest giving way to red maple giving way to 

northern hardwoods-hemlock forest followed by fire resulting in a 

new aspen forest. If this model is true and inexorable, as some argue, 

then managers can let nature take its course or harvest to emulate 

the principal regional disturbance and let nature take its course. The 

convergent model is one with one endpoint from different beginnings A  C and B  C and has been attributed to Clements (1936). 

For example, Douglas-fir being replaced by western hemlock and 

red alder being replaced by western hemlock. If this is true—that 

succession proceeds to a single climax state no matter what starting 

conditions are—then managers can let nature take its course, and 

it does not matter what is done in active management, old growth 

develops anyway. A less common model is the divergent model in 

which A can go to either B or C depending on feedback mechanisms that magnify initially minor differences (e.g., differences in 

soil) and perpetuate the divergence. For example, postfire aspen may 

go to pine, oak, or maple forest. This model calls for careful consideration of initial conditions, context, site qualities, and desired 

future condition in formulating how to nudge the system onto the 

desired trajectory. The parallel model says A–disturbance A and 

B–disturbance B as is common in boreal forests of North America. 
244 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Managers can let nature take its course or “cut and run.” Finally, 

a Gleasonian individualistic model recognizes multiple pathways 

of succession and emphasizes continuous change without necessarily a stable endpoint. Such complexity calls for careful AIM to 

achieve explicit, diverse goals. Our collective empirical experience 

in deforestation and oversimplified monocultures and near monocultures obviates the first four models even in the long term, given 

past and present human activities of fire exclusion, logging, grazing, 

introduction of exotic forest pests and diseases, and global climate 

change. But the larger question is really whether in most forest management situations are we more often faced with succession or are 

we more often faced with development (Frelich 2002)? And, again, 

development is as, or more, often envelopment than it is succession. 

Envelopment entails adding niche dimensions and species but not 

necessarily loss of species. Concepts of development through envelopment always recognize that disturbance regimes are complex, interactions abound, and spatial context is important, including both 

landscape permeability to dispersal and larger scale neighborhood 

effects of sources of colonizers and ameliorators of environmental 

conditions. Here again, good AIM is required.

Problems

The problem we face is not so much lack of information but a means 

to separate the wheat from the chaff (knowledge from ideology), a 

universally acceptable way of synthesizing and integrating this information to produce some basic principles to guide conservation 

activities (sidenote 41), and institutions capable of collaborative AIM

in the present and future. Traditional ecosystem science emphasizing energy and material flows and population biology emphasizing 

genetic and species diversity have yet to be reconciled for conservation purposes. As with many environmental problems, social and 

psychological factors impede progress as much as disciplinary tunnel vision within the sciences (Dietrich 1992, Harris 1996, Kesey 

1982). For example, temperaments with an “internal locus of control” prefer taking action to achieve objectives (AIM for multiple values); those with an external locus of control prefer to let things happen (let nature take its course). Field trips for empirical assessments 

of assumptions, experiential group learning and, especially, formal 

feedback from experienced professionals can provide “reality checks” 

(Carey et al. 1999a). Professional experience and inherent biophysical variability argues against both cookbook approaches and leav-
C H A P T E R 7 From Ecology to Forest Management 245

The accumulated 

research does 

provide useful 

information—not 

so much on absolute 

species diversity as 

on forest dynamics 

and expansion 

of niche space 

as prerequisites 

to high relative 

diversity.

ing things to chance and for thoughtful application of principles. 

Thus, in the context of conservation of nature and the goods and 

services it provides, the accumulated research does provide useful 

information—not so much on absolute species diversity as on forest 

dynamics and expansion of niche space as prerequisites to high relative diversity. Complexity of niche space contributes to ecosystem 

resiliency and to trophic pathways supporting plant, fungal, invertebrate, and vertebrate communities, including keystone species, keystone complexes, and prey and predator complexes characteristic of 

old-growth Douglas-fir forests (Carey et al. 1999b, 1999c). Theories 

about complexity and expansion of niche space provide a substantial basis for ecological forestry and the production of a variety of 

goods, services, and values (Carey et al. 1999b). But, niche theory 

and theories of community development do not necessarily answer 

all pertinent questions about conservation of rare species, cryptic 

species about whom little is known, total species diversity, or genetic 

diversity. The ecological sciences offer little in the way of assurances 

about human behavior in resource management—fidelity, trustworthiness, scholarship, and degree of intentionality.

Biological and Functional Diversity

Much research on biodiversity has focused on sessile species and the 

roles of disturbance, equilibrium, and competition (Connell 1978, 

Connell et al. 1987, Connell and Slatyer 1977, Pickett 1980, Pickett and White 1985a, Platt and Connell 2003, Roberts and Gilliam 

1995). Concern about lichens, bryophytes, vascular plants, fungi, and 

invertebrates resulted in severe restrictions on forest management on 

federal lands in the Pacific Northwest, despite the general consensus 

that disturbance underlies biodiversity (Levin and Paine 1974, Paine 

et al. 1998, Petraitis et al. 1989, Pickett 1976, White 1979, White 

and Jentsch 2001) (sidenotes 42, 43). One definition of disturbance

is “any rapid release or reallocation of community resources”—tree 

fall, silviculture, and hurricanes can all increase diversity (Sheil and 

Burslem 2003). Of course, silviculture has been used most commonly to decrease diversity, as is common in plantation monocultures 

where any species other than the crop tree species are discouraged 

by maintaining high tree densities, mechanical destruction, and 

chemical applications (Carey 1998b). Another definition of disturbance is “a relatively discrete event in time that disrupts the ecosystem, community, or population structure and changes the resources, 

substrate availability, or physical environment” (White and Pickett 
246 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 39—Creating biocomplexity in Pacific Northwest 

forest ecosystems includes:

 Maintaining extant species 

diversity.

 Restoring lost species diversity.

 Ensuring a minor deciduous 

component in coniferous forest 

ecosystems.

 Maintaining deciduous forest, meadow, and grassland 

ecosystems historically present 

in predominately coniferous 

forest landscapes.

 Promoting spatial heterogeneity that produces a diverse 

array of vegetation site types 

(habitat breadth).

 Promoting a diversity of foliage height profiles among the 

site types.

 Promoting structural diversity 

in tree sizes and conditions 

(live, decadent, dead, standing, 

and fallen).

 When historically common, 

maintaining a proportion of 

the landscapes in forest ecosystems of the type that resulted 

from catastrophic disturbances 

such as fire or wind.

 Protecting and promoting 

the growth of large trees on 

areas prone to mass wasting or 

erosion, including areas of colluvium, shallow rapid landslide 

potential, and deep-seated 

landslide potential.

 Protecting wetlands.

 Promoting a shifting steadystate mosaic of various complex stages of forest development within the landscape.

 Promoting all this heterogeneity and patchiness on a scale of 

0.2 to 0.5 hectare within ecosystems and 10 to 200 hectares 

among ecosystems within the 

landscape.

1985) (sidenote 44). Disturbances localized in space and time produce patterns of heterogeneity by renewing limiting resources and 

permitting their use by species that are not among the dominant 

species (Levin and Paine 1974). Disturbances comprise continua of 

minor to major events and changes, endogenous and exogenous to 

the community, from tree fall to volcanism and from succession to 

climate change (White 1979). Because of disturbances, forests are 

structurally dynamic. Dynamic structure produces dynamic environments (chemicals, temperature, moisture, airflow, radiation, and 

species mix) within the community. The spatial and temporal heterogeneity that results provides the setting for evolution of life history traits adapted to persistence in heterogeneous landscapes (sidenote 45). Science suggests (1) most forests are subject to small-scale 

local disturbance and occasional larger disturbances, (2) many other 

processes unrelated to disturbance also interfere with the competitive exclusion that reduces diversity, but (3) there is widespread occurrence of forests of low diversity near younger, richer forests (Sheil 

and Burslem 2003).

In the late 20th century, research on vertebrate diversity emphasized island biogeographic theory, metapopulations and demographic stochasticity, dispersal and colonization processes, and, in 

terrestrial systems, mountaintops and forest fragmentation (Brown 

1971, Gotelli 1999, MacArthur and Wilson 1967, May 1975, Simberloff and Abele 1976, Whitcomb et al. 1976). These studies assumed more-or-less static ecosystems and landscapes. More recent 

research emphasizes stochasticity in every process, chaos theory and 

Panarchy theory (dynamic systems), and neutral theories, for example, random sampling of regional species pools (Hubbell 2001). 

Perhaps the only generally accepted principle from that time is that 

there is no reason to believe that every biotope-patch-ecosystem in 

the landscape should be populated by every species in the regional 

species pool capable of living in the environment of that patch. Island biogeographic theory informs conservation biology, wherein 

management attempts to create systems of self-maintaining islands 

(reserves) and connecting corridors. An emerging generalization in 

conservation biology is that high levels of environmental stochasticity increase the likelihood of population extinctions. Coexistence 

theory, however, suggests there are circumstances in which environmental stochasticity increases the chance of persistence, depending 

on the interactions of life history traits and environmental variability (Higgins et al. 2000). Principles from conservation biology 

were used to design late-successional reserves on federal lands in the 

Pacific Northwest in order to provide at least temporary refuge for 
C H A P T E R 7 From Ecology to Forest Management 247

Figure 41—Western hemlock 

saplings grow from a nurse log. Photo 

by T. Wilson.

Disturbances 

localized in space 

and time produce 

patterns of 

heterogeneity by 

renewing limiting 

resources and 

permitting their 

use by species that 

are not among the 

dominant species.

species not known to inhabit simplified second-growth forests. A 

sole focus on preserving species populations, subspecies, and species 

through the creation of reserves, however, is inappropriate even if 

the ecological qualities of reserves could be maintained in perpetuity 

(Franklin 1993b). Conservation, however, must move beyond reserve 

strategies because it is fundamentally impossible to deal with more 

than a small fraction of even the known species on a species-byspecies basis, most species are unknown, and, in reality, biotic communities set aside in reserves will change.

Old forests that have been set aside are not in static equilibrium; 

they are in a more-or-less dynamic equilibrium undergoing slow 

change and eventually heading toward catastrophic change, according to Panarchy theory (Gunderson and Holling 2002) and history. Without major disturbance in old-growth Douglas-fir forests, 

Douglas-fir eventually (on the scale of centuries) will be replaced by 

western hemlock, Pacific silver fir, or other shade-tolerant species 

(fig. 41). The new biotic community, dominated by shade-tolerant 

species and no longer being disrupted by the death and falling of 

large dominants, may become more simply structured and less compositionally diverse than the immediately preceding developmental 

stages. The same holds true for other forest types (Bormann and 

Likens 1979). For example, in the absence of intermediate disturbance, a mix of subalpine fir and Engelmann spruce will be replaced 

by spruce (Oosting and Reed 1952, Parish et al. 1999). Mixed-oak 

forests may follow any one of three developmental pathways, but all 

end in dominance by white oak—timing may be variable, disturbances may change successional dynamics, and exact species composition may determine the occurrence of species-specific waves of 

mortality (Goebel and Hix 1997). 

In many forests, internal dynamics 

and endogenous disturbances maintain 

diversity (and resilience) over long periods. Sugar maple replaces yellow birch 

and is replaced by American beech—but 

falling of isolated large beech allows yellow birch to reestablish and a shifting 

mosaic to form within the community 

(Forcier 1975). Gap-phase replacement, 

with a mosaic of patches containing varying proportions and densities 

of saplings and seedlings, characterized Minnesota maple-basswood forests (Bray 1956) in a process similar to 
248 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 40—References on 

forest ecology and management:

	Allen et al. 2001

 Bergeron 2000

 Bobiec 2002

 Bobiec et al. 2000

 Bormann and Likens 1979

 Busing and White 1993

 Canham et al. 1990

 Carey 2003a

 Carey et al. 1999a, 1999b

 Clements 1916, 1936

 Connell and Slatyer 1977

 Cooper 1960

 Dale et al. 1986

 Denslow 1980

 Donnegan and Rebertus 1999

 Forcier 1975

 Foster et al. 1996

 Fox 1977

 Franklin and Waring 1980

 Franklin et al. 1987

 Franklin et al. 2002

 Frelich 2002

 Goebel and Hix 1997

 Grime 1977

 Halpern 1988, 1989

 Halpern and Franklin 1990

 Harrod et al. 1999

 Holling 1992

 Huff 1988

 Jones 1945

 Kimmins 1996

 Massman 1982

 Odum 1969, 1971

 Oliver 1981

 Oliver and Larson 1996

 Oosting and Reed 1952

 Parish et al. 1999

 Peet and Christensen 1987

 Peltzer et al. 2000

 Perry 1994, 1998

 Perry et al. 1989

 Pickett 1976

 Poage and Tappeiner 2002

 Roberts and Gilliam 1995

 Ryan et al. 1997

 Shugart 1984

 Shugart and West 1980

 Stewart 1986

that observed in plant communities in England (Watt 1947). Fox 

(1977) compared virgin forests in Michigan, Tennessee, Pennsylvania, Florida, and Wyoming and concluded that forests maintaining 

a compositional equilibrium did so through a dynamic equilibrium 

of patch types, changing in time and space. His results did not support the hypothesis that mosaics of spatially fixed microsites that favored one species over another would provide for species coexistence 

in perpetuity (Freyer and Ledig 1972). Ziegler (2002) reported similar results in her study of New York Adirondack forests and review 

of studies in Michigan, Pennsylvania, and New York. Nevertheless, 

fine-scale (within biotope) environmental heterogeneity certainly 

has the potential to contribute to biological diversity (Frelich 2002). 

Fox (1977) proposed three hypotheses about how autogenic (self-organizing) biotic heterogeneity is sufficient and important to species 

diversity: (1) forest tree species dynamics are the result of interactions between dominant and subordinate trees at the scale of one to 

a few large canopy trees; for example, a dominant plant can provide 

a microhabitat for a younger or smaller plant; (2) processes leading 

to interactions, especially those regulating density and species composition, all operate on very local scales (except seed dispersal); and 

(3) local regulation of species composition occurs because dominant 

trees interact directly with smaller plants through root and mycorrhizal grafting thereby uniquely altering the mortality and growth 

of various species of seedlings and saplings that are nearby. Thus, the 

important scale of heterogeneity was one to six or so canopy trees, or 

about 0.2 hectare. A duality of scales of patchiness was found in oldgrowth hemlock-hardwood forests maintaining a dynamic compositional equilibrium in the absence of major exogenous disturbances 

in the Smoky Mountains of Tennessee (Busing and White 1993). 

Observed canopy gaps (averaging 0.01 hectare) and physical structure (biomass, basal area) varied with these gaps; but spatial variation in composition occurred at 0.5 to 1.0 hectare reflecting the interaction of canopy gaps, microhabitat, patterns of seed dispersal, 

vegetative regeneration, and species interactions. These authors noted that the potential for high spatial variability of compositional parameters has long been recognized and that 0.5 hectare is the minimum area for evaluating change in physical parameters, and about 

1 hectare is the minimum for compositional parameters (as both relate to trees, only). 

Succession to a climax community can result in lowered diversity (at least of vascular plants and vertebrates) and lowered biocomplexity as species are lost through succession (Whittaker 1975) 

and even the abundance of fallen trees and standing decadent trees 
C H A P T E R 7 From Ecology to Forest Management 249

 Swedish National Board of 

Forestry 1990

 Tappeiner et al. 1997

 Van Pelt and Franklin 2000

 White 1985

 Whittaker 1956, 1960, 1965, 

1975

 Whittaker and Levin 1977

 Winter et al. 2002a, 2002b

Sidenote 41—Some basic 

principles of forest conservation:

 Protect highly valued rare, 

fragile, and threatened ecosystems.

 Maintain healthy forests across 

landscapes and regions, and 

especially near where people 

live and work.

 Manage forest for multiple 

values by maintaining legacies, 

by using long rotations (time 

between major harvests), and 

actively managing for biocomplexity.

 Encourage people to experience the forests and to learn 

about their functions and 

values.

Sidenote 42—The Intermediate Disturbance Hypothesis 

(Connell 1978)—“the highest diversity of tropical rain forest trees 

should occur either at an intermediate stage in succession [development] after a large disturbance or 

with smaller disturbances that are 

neither very frequent nor infrequent; either represents an open 

non-equilibrium.”

decreases (Bormann and Likens 1979, Carey 1983). For example, 

northern hardwood forests over 200 years old in West Virginia had 

less structural complexity (e.g., a lack of cavity trees and lack of 

understory) than 80- to 100-year-old second growth nearby. Similarly, Scheller and Mladenoff (2002) found understory diversity was 

lower in old-growth northern hardwood forests in Wisconsin and 

Michigan than in even-aged second growth which, in turn, had less 

diverse understories than uneven-aged second growth. Differences 

in species composition in the understory were the result of sunlight 

and coarse woody debris; each age class had its own characteristic 

combination of understory composition, diversity, and spatial patterning. Large- and small-scale disturbances, such as hurricanes and 

blowdowns, respectively, promoted various aspects of understory regeneration in Southeastern hardwood forests, such as seed germination, growth of seedlings and established plants, and fruit and seed 

production (Kwit and Platt 2003). Mid-altitude forests on Mount 

Rainier that have not had a major disturbance in close to a millennium have the appearance of a much younger forest in biomass accumulation stage—most of the original dominants have fallen, and 

even the fallen trees are well-decayed and indistinguishable from 

the forest floor. Not much is known about the effect of quasi-climax 

stages on micro-organisms, nonvascular plants (lichens, bryophytes), 

fungi, and invertebrates. For example, the Quinault Research Natural Area on the Olympic Peninsula of Washington, is over 500 years 

old (middle-aged old growth) and dominated by very large western 

hemlock and Sitka spruce and large, fallen trees (fig. 42). During a 

3-year study, it supported neither flying squirrels nor spotted owls 

(Carey 1995). It did, of course, support a great diversity of other organisms, including ferns, lichens, mosses, and liverworts (and, most 

likely, a high diversity of organisms in the forest floor). 

In any case, it is likely the old growth of today eventually will 

be affected by catastrophic disturbance. The eruption of Mount St. 

Helens in 1980 destroyed old-growth forests set aside for spotted 

owls (Ruediger 1985) (fig. 43), recapitulating an earlier eruption in 

1480 (Agee and Krusemark 2001). Volcanism and other geologic 

processes (such as those associated with glaciation and glacial recession) have shaped the landscapes in Washington and Oregon not 

only through basaltic lava flows, creation of pumice fields, lahars, 

and massive eruptions, but also long-distance ash deposition and 

large-scale flooding. An earthquake that caused substantial tree fall 

may have set the stage for a massive fire in 1700 near Mount Hood, 

and a sunspot minima may have led to global cooling, drought, and 

lightning that led to a large fire event in 1493 (Agee and Krusemark 
250 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 43—If disturbance 

underlies biodiversity, why is there 

such an emphasis on reserves 

and restricting management even 

in second growth? Three likely 

explanations: 

 Many see old-growth species as “K-selected” species, 

adapted to stable conditions 

which are increasingly rare 

and thus in need of protection 

when they exist, as defined by 

the presence of such a species.

 A perverse adaptation of the 

precautionary principle (Principle 15 of United Nations 

1972) by which any uncertainty precludes human action 

and proponents of action must 

demonstrate efficacy of action.

 Deep distrust among ecological disciplines, managers, 

regulators, and conservation 

groups based on the history of exploitation of natural 

resources in the United States. 

Jack Ward Thomas (2002), 

former leader of the Forest 

Ecosystem Management Assessment Team that provided 

the basis for the Northwest 

Forest Plan and former Chief 

of the USDA Forest Service, 

provides a review.

Figure 42—Regine Carey stands 

between large, fallen trees on the 600-

hectare Quinault Research Natural 

Area, an undisturbed old-growth forest of the Olympic Peninsula. Photo 

by A. Carey.

2001). Windstorms in 1921 and 1962 destroyed large areas of forest in western Washington and Oregon (Henderson et al. 1989). At 

the same time, the introduced white-pine blister rust changed the 

nature of Cascade old-growth forests, adding numerous large snags 

but decimating various species of pine. Ponderosa pine now infiltrated by Douglas-fir has increasing vulnerability to catastrophic 

destruction (Harrod et al. 1999). 

Most old growth in the Pacific Northwest developed after catastrophic fires 300 to 600 years ago. “Natural fire rotations” appeared 

to be 465 years for Mount Rainier and 347 years for Mount Hood 

(Agee and Krusemark 2001). Fires were more frequent in the Oregon 

Coast Ranges in the 19th and 20th centuries ( Juday 1977, Wimberly 

and Spies 2001). In some areas, fires reduced the prevalence of western hemlock, a species poorly adapted to fire. These fires have been 

attributed to the end of the Little Ice Age but were concurrent with 

the arrival of settlers from the Eastern United States. Both settlers 

and Native Americans used fire to maintain grasslands, promote 

grazing, and clear forest. As disturbance regimes change, patterns 

of forest development that follow future catastrophic disturbances 

may differ from the patterns of the past—the climate, natural and 

anthropogenic disturbance regimes, regional and local species pools, 

and regional and landscape environmental contexts already differ 

from the past.

Natural disturbances, timber harvest, and land use changes have 

produced an uneven distribution of old growth with large intervening areas dominated by developed areas and managerially simplified 

competitive-exclusion stages of second-growth forest. Landscapes 

dominated by competitive-exclusion stages (through their negative 
C H A P T E R 7 From Ecology to Forest Management 251

Figure 43—Between 1980 and 

1986, Mount St. Helens had several 

small steam and ash eruptions as a 

series of dome building eruptions built 

the 1,000-foot tall lava dome in the 

crater. This photo shows a dome-shattering explosive eruption that occurred in the fall of 1982. Photo by P. 

Frenzen.

effects on dispersal and colonization processes) may prove more detrimental to nature conservation than either (1) large areas of forests 

destroyed by catastrophe but contain substantial embedded legacies 

or (2) dispersed clearcuts in landscapes of forests actively managed 

on long rotations in which complex stages of forest development 

predominate and landscape permeability is maintained (Carey et al. 

1999c). Managerially simplified stands with exacerbated competitive 

exclusion and biomass accumulation work against interactions of environmental factors and the functional ecologies of species that are 

the foundation for maintenance of plant species diversity, not only 

in temperate forests but also in boreal forests (Messier et al. 1999) 

and diversity in plant communities in general (Grime 1977). Even 

productivity declines, often quickly, when biomass accumulates rapidly and a syndrome of changes leads to reduced carbon assimilation 

(Ryan et al. 1997). 

Plants require energy, water, and mineral nutrients for growth; 

natural environments, however, differ in orders of magnitude in 

the availability of these resources. For example, light varies 100-

fold from the canopy to the rain-forest floor; precipitation varies 

500-fold from deserts to tropical rain forest; and nitrogen ranges 

almost 300-fold from the poles to the tropical rain forest (Chapin 

et al. 1987). The functional ecology of plants can be represented by 

a three-sided triangle of interaction wherein the sides represent the 

importance of competition, disturbance, and environmental stress in 

determining the strategy a plant species (or even a life history stage) 

takes. Grime (1977) labels these strategies as C (high competitive 

ability in stable environments), S (high stress tolerance with reduction in vegetative and reproductive vigor), and R (short lifespan and 

high seed production in severely disturbed environments) (fig. 44) 

(see table 15). In plants, R stands for ruderal; in animals, r is the 

symbol of a measure of reproductive ability. Animal ecologists use K, 

the symbol for carrying capacity, to represent strategies that emphasize long life, low reproduction, and survival in stable environments 

and r to represent short life, high reproduction, and adaptation to 

volatile environments (Hutchinson 1978, Reznick et al. 2002) (fig. 

45) (see table 20). Grime’s triangle, however, allows subdivision of 

a 3-D space to describe various life histories, and he recognizes that 

conditions on a biotope change through time as plants modify the 

environment. Species in a dynamic community exhibit a multiplicity 

of strategies—this multiplicity is one basis for ecosystem resilience. 

In forest communities, architectural adaptations allow seedlings of 

different species to grow under different environmental conditions 

(Messier et al. 1999). In other words, complex, dynamic ecosystems 
C-S C-R

C-S-R

S-R

100 0

25

50

75

100

75

50

25

0

100

75

50

25

0

Ic (%)

Is (%)

I

d (%)

C

S R

Sitka spruce Scotchbroom

Oregon white oak Bull thistle

252 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 44—Model describing the 

various equilibria between competition, stress, and disturbance in 

vegetation and the location of primary 

and secondary strategies. Ic—relative 

importance of competition (_____), 

Is—relative importance of stress 

(-----), and Id—relative importance 

of disturbance (— • —). Ruderal (R), 

competitive (C), and stress-tolerant (S) 

strategies along the r–K continuum 

(adapted from Grime 1977). Graphic 

by A. Wilson; oak photo courtesy of 

USDA Forest Service; thistle photo 

courtesy of USDI Bureau of Land 

Management; Sitka spruce photo by 

T. Wilson; scotchbroom photo by A. 

Carey.

make room for a diversity of species within the various functional 

groups. Adaptations include steep leaf angles (to minimize photoinhibition by allowing more light to penetrate to lower leaves), 

horizontal leaves (to shade competitors), and allocation of carbon to 

leaves versus stems and branches. Lower relative growth rates and 

higher allocation to roots is more characteristic of late-seral forest (species that emphasize maintenance of accumulated biomass) 

than early-seral forest species (species scrambling to compete for 

ephemerally available resources). Allocating carbon to foliage and 

stem growth helps in competition for light; allocating carbon to fine 

roots enhances competitive ability for nutrients. In conifers, pines 

are less efficient at intercepting light (0.16 STAR [shoot silhouette 

to needle surface] ratio) than firs (0.28). With diminishing light 

and increasing shade tolerance, lateral branch growth is favored 

over height growth, number of whorls and interwhorl branches is 

decreased, live-crown ratio is decreased, and horizontal display of 

needles and branches is increased (fig. 46). Thus, crown architecture must achieve some balance in a complex system by performing conflicting tasks such as enhancing photosynthesis, adapting 
Northern flying squirrel Northern spotted owl Roosevelt elk

Examples of K-selected species:

Gray wolf

Banana slug Montane shrew Red-legged frog Deer Mouse

Examples of r-selected species:

C H A P T E R 7 From Ecology to Forest Management 253

Figure 45—Examples of K- and 

r-selected species. Graphic by A. 

Wilson; flying squirrel photo by W. 

Colgan III; banana slug photo by T. 

Wilson; owl and shrew photos courtesy of USDA Forest Service; elk and 

mouse photos by A. Carey; red-legged 

frog photo by M. Jennings, U.S. Fish 

and Wildlife Service; wolf photo by 

G. Kramer, U.S. Fish and Wildlife 

Service.

for survival in the winter, and allowing light to penetrate to deeper 

layers—one result is the conical crown of many conifers (Messier 

et al. 1999). As trees grow, their requirements for sunlight change. 

The tuliptree requires 12 percent full sunlight at 1-meter tall but 25

percent full sunlight when 10 meters tall. Some conifers produce one 

kind of needles when growing in the shade and must produce new, 

different needles for growing in sunlight. Shade-tolerant trees like 

western hemlock and some firs and spruces can grow for extended 

periods in a shaded understory, awaiting release by large falling trees 

causing gaps, severe windstorms toppling the overstory trees, and 

outbreaks of defoliating insects (Messier et al. 1999). Thus, species 

diversity in forests is dependent upon large and small gaps and functional relationships among size of canopy opening, nature of aboveand belowground environments, and the response of the seedlings 

and saplings of various species. Natural thinning (self-thinning) and 

even intentional (managerial) thinning may produce deaths of individual trees that may be relatively inconspicuous but collectively determine much of the structure, development, and dynamics of forest 

ecosystems (Peet and Christensen 1987, Thysell and Carey 2001a). 
254 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 44—Order and 

disorder—“To many ecologists, 

natural disturbances are key 

ecosystem processes rather than 

ecological disasters that require 

human repair” so said prominent 

ecologists in the public debate 

over removal of damaged trees 

after natural disturbance and 

subsequent attempts at restoration (Lindenmayer et al. 2004). 

This quotation is an especially 

telling statement of worldviews 

and a policy opinion. It is telling 

because these leading scientists 

lumped all disturbances into one 

group rather than distinguishing among small, intermediate, 

and catastrophic disturbances or 

between autogenic (endogenous 

disturbances that are normal 

and regular parts of ecosystem 

development) and exogenous 

forces that may be either part of a 

disturbance regime characterizing 

a region over a long term or rare 

geologic or weather events. The 

quotation, however, is prefaced 

to refer to “Recent large-scale 

natural disturbances including 

wildfires that burn [millions of 

hectares].” 

What are the pertinent 

definitions of the key words according to the Oxford English 

Dictionary?

 Disturbance: an outbreak of 

disorder ... interference with 

the ... due course ... of any ... 

process.

 Disaster: anything that befalls 

of a ruinous or distressing nature ... a sudden .... calamity.

 Catastrophe: an event producing a subversion of the order 

or system of things ... a sudden and violent change in the 

physical order of things ... affecting the earth’s surface and 

the living beings upon it....

Shugart (1984), however, emphasized that the individual attributes 

and population dynamics of species as they relate to competition, although important, interact with processes of facilitation and smallscale (0.1 to 0.2 hectare) gap formation, compared to even smaller 

gaps (0.04 to 0.08 hectare) in tropical forests. Thus, temperate forests demonstrate a regularity of pattern indicative of a multiplicity 

of plant-environment and plant-plant interactions; Shugart (1984) 

thus joined Odum (1969) in stressing self-organizing phenomena.

In summary, research has provided useful and important insights 

about the processes of plant community development in forest ecosystems, mechanisms leading to and maintaining biological diversity, and the ramifications of large-scale anthropogenic and natural 

disturbances for landscape function. As a practical matter, individual 

studies and individual syntheses generally are narrowly focused. This 

narrow focus, at times, has resulted in emphasizing reductionism 

at the expense of holism (Barbour 1996). Narrow, intradisciplinary 

foci have led to unnecessary polarization of worldviews among scientists and among conservationists, including false dichotomies 

of management by preservation versus intensive management for 

commodities and maximum economic return on investment (sidenote 46). Such dichotomies cloud the view of the bigger, long-term 

picture of conservation of nature. Maintaining these dichotomies, 

however, is a choice, not inevitability. We have the potential collectively to develop the holistic, integrated worldviews that are needed 

for effective conservation. It seems that an emphasis on ecological 

processes and system dynamics underlying forest development and 

maintenance of biodiversity offers more promise than a focus on 

specific structural elements, particular endpoints of structural development, particular patterns of a limited set of idealized “structural 

stages,” rare species, absolute species diversity, or leaving recovery of 

ecosystem and landscape function to time and chance alone.

Processes Underlying Forest Development

Ironically, it is the history of environmental fluctuations, 

natural disturbance processes, and subtle, often indirect, 

human impacts that shape the characteristic structure, 

composition, and ecosystem processes of old growth (Foster et al. 1996).

Ecologists have been arguing about the nature of virgin forests 

since 1924 ( Jones 1945). Jones’s review documented common ages 
C H A P T E R 7 From Ecology to Forest Management 255

Thus, there are disturbances, 

localized or widespread, mild or 

intense, acute or chronic; and 

there are catastrophes—acute, intense, and widespread. Some disturbances are ecosystem processes 

(endogenous to the ecosystem) 

and some are exogenous forces 

destructive of the established 

system, its processes, and its biological diversity. Human reaction 

to disturbances differ with the 

intensity, acuteness, and distance 

from the observer. Policies on 

how to deal with disturbances 

are by definition based on human 

worldviews and human values, not 

“objective” science; they are often 

formulated hastily during and 

immediately after major disturbances. The scientists propose “... 

to formulate salvage harvest policies before major disturbances ... 

exemption of [certain] large areas 

... [and] good planning should 

guide the timing and intensity of 

salvage harvesting.”

Figure 46—A western hemlock’s 

unique lateral branching allows it to 

survive in the shadow of larger conifers. Photo by A. Carey.

of dominants around 300 years old in beech forests in Europe, 350

years in pine forests of Asia, 350 years in hemlock forests of eastern 

North America, and with the oldest and largest trees (750+ years 

for several species) in California, Oregon, and Washington. Coastal 

British Columbia trees, however, rival those in other parts of the 

Pacific Northwest. Northern coniferous forests seemed smaller in 

stature (of course, we now know the oldest trees may be quite small 

evergreens in xeric parklands and woodlands). He noted that there 

were many types of structure in virgin forests: even-aged, singlestoried, uniformly closed-canopy forest; two or more ages in either 

separate stories or separate groups; all ages present, intimately intermingled, with irregular open canopies; all ages in a mosaic of evenaged groups; and all ages present with a regular, uniform canopy and 

a storied structure. The most common structure seemed to be dominance by old stems, but with a wide range of ages, and two to three 

canopy gaps per hectare. Fire seemed of supreme importance in the 

origination of natural forests but “tempest,” fire, root-rot, heart rot, 

insect attack, and disease produced various phases of senescence, or 

large amounts of decadence. Climatic changes brought about “readjustment” of dominant species. But in all cases, the forests were 

in dynamic equilibrium with individuals dying and being replaced 

by individuals of other species with compensatory changes taking 

place elsewhere; in other words, the shifting-steady-state mosaics 

later described by Fox (1977), Bormann and Likens (1979), Shugart 

and West (1980), Pickett (1980), Oliver (1981), and Franklin et al. 

(2002). Not too bad for the turn of the century. A more recent review of old growth in temperate and boreal forests of Europe (Nilsson et al. 2003) found that the older canopy trees were 200 to 300

years old even in forests without significant harvests for over 2,000

years. Large (more than 70 centimeters) d.b.h. trees numbered 10 to 

20 per hectare (40 to 60 square meters basal area per hectare) depending on forest type and site, with 10 percent of all standing trees 

dead, and with snags composing 30 percent of dead tree volume. 

These deciduous and mixed deciduous-conifer old-growth forests 

were judged to be similar to those in the Eastern United States. 

But the authors found that old growth in the Pacific Northwest had 

older, larger trees, fewer trees per hectare, but with greater basal area 

and total volume of trees and with a larger proportion (30 percent) 

of standing trees dead (fig. 47).

Development of forest ecosystems from reorganization through 

old growth is an interacting complex of processes (some of which 

counteract one another) that lead to characteristic trophic structure (food webs) and material cycles (Beckage et al. 2000, Bergeron 
256 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 45—Generalities from studies of disturbance 

(White and Jentsch 2001): 

 Disturbance is a primary cause 

of spatial heterogeneity and 

influences competition, environment, and substrate and 

resource availability.

 Disturbance is crucial to biotic 

diversity and an important 

evolutionary force that produces both complementarity 

and redundancy in biota that 

promote ecosystem stability.

 Disturbances shape communities to be resilient in the 

face of disturbance through 

functional redundancy.

 Humans are a major source 

of minor and major environmental disturbances and 

influence the rate and intensity 

of natural disturbances, often 

to the detriment of biological 

diversity.

 Disturbances differ with 

topography, climate, and soil 

development.

 Disturbances differ with feedback and interactions—disturbance can promote further 

disturbance.

 Disturbances differ in heterogeneity, patch size, intensity 

and severity, and legacies.

 Disturbances differ in space 

and time.

 Systems respond to disturbance in three ways: threshold 

responses, scale-independent 

responses, and continuous 

responses.

 Species and communities 

differ in their responses to different disturbances.

2000, Odum 1969). Development after catastrophic destruction and 

reorganization usually (1) is an orderly process that is reasonably 

directional and therefore predictable, (2) results from modification 

of the physical environment by the community, and (3) culminates 

in a stabilized ecosystem in which biomass and symbiotic function 

constitute a strategy of homeostasis, but not necessarily a classic 

old-growth condition (see table 17). The reorganization phase itself 

is highly variable in nature and length—in the Pacific Northwest 

regeneration of trees in sufficient number to create a forest can take 

30, 50, or more years after a catastrophic fire (Huff 1995, Poage and 

Tappeiner 2002, Winter et al. 2002a), and spatial heterogeneity can 

be very high owing to legacies and differences in seed sources. 

In late-seral forests, shifting-steady-state mosaics (dynamic 

patches) (Pickett and White 1985b) provide for a degree of dynamic 

equilibrium through gradual changes in space and time both within 

forest ecosystems and across forested landscapes. Various exogenous 

disturbances and environmental heterogeneity within the biotope 

interact with a variety of ecological processes to promote biocomplexity within the ecosystem. Without disturbances (exogenous and 

endogenous), the development of biocomplexity will be truncated. 

Biocomplexity within the biotic community develops as patches begin to differ in character, rate of change, and type of change over 

time more than would be expected on a uniform site without successive disturbances. Thus, forest development in lowland, carefully 

cultured plantations is likely to be quite different than in upland 

heterogeneous sites subject to various minor and intermediate exogenous disturbances but little intensive culture. 

It is essential to effective management to realize that the catastrophic destruction and the legacies it generates set the stage for 

the development to follow. Different disturbance regimes set different stages (Frelich 2002). The effects of timber harvesting and other 

human activities may be quite different from those of most natural 

disturbances in the case of clearcutting and somewhat similar in the 

case of partial cutting (sidenote 47). In numerous locales in North 

America, including the Capitol Forest of Washington (Capital Forest: 

The Forest That Came Back, Felt 1975), unregulated timber harvesting 

led to deforestation and erosion. In both western Oregon and Washington in the 20th century, forests destroyed by wildfire reburned; for 

example, the forest destroyed by the Tillamook Fire of 1933 burned 

again in 1939, 1945, and 1951, probably as a result of human activity 

(Agee 1991). Potential for reburns can be high in early succession to 

Douglas-fir on moist sites, but once crowns close, potential for fire 

decreases. Forests may then develop for another 200 to 500 years 
C H A P T E R 7 From Ecology to Forest Management 257

Sidenote 46—False dichotomies—A major wildfire 

in southwestern Oregon ignited 

a firestorm of countervailing 

philosophies among prominent 

scientists that precluded intentional analysis and planning 

(Lindenmayer et al. 2004, Sessions et al. 2003, Thomas 2002). 

Should the forests have been 

managed to reduce fuels before 

the fire? Should damaged timber 

be salvaged for its economic value 

and jobs? Should damaged timber 

be salvaged to underwrite restoration efforts? Does salvage cause 

damage rather than speed recovery? Should nature be allowed 

to take its course? Should the 

reorganizing forest be managed to 

speed recovery of late-seral forest 

conditions? These questions are 

less about science and more about 

value and purpose. The most pertinent questions are why, where, 

when, how, how much, in what 

manner, for what specific purpose, 

at what risk, with what uncertainty, for what collective result?

Figure 47—Old-growth trees on 

the Olympic Peninsula—some living, 

some dead. Photo by T. Wilson.

with their character conditioned by a specific catastrophic disturbance and the legacies it left. If the forests go undisturbed for 700 to 

1,000 years, Douglas-fir will be lost, and Pacific silver fir and western 

hemlock will be the primary seed sources of a new postfire regeneration. In more mesic sites in the Oregon Cascades, partial burns after 

canopy closure may occur every several decades or centuries; forest 

development follows a different course, with a mixed dominance of 

Douglas-fir and other species maintained. And in dry sites in southwestern Oregon, partial burns are common; true firs and hemlock 

may be rare and multiple age classes of Douglas-fir and hardwoods 

such as madrone or tanoak may be common. Thus, the importance 

of biological legacies and disturbance regimes and their contributions to reforestation has been recognized since Clements’ work on 

forests in 1916, the Hubbard Brook forest experiments of the 1960s, 

and reforestation of the area around Mount St. Helens in the 1980s 

(Franklin and MacMahon 2000, Franklin et al. 2002). 

The most important ecological insight from studies of natural boreal, montane, and temperate coniferous forests and tropical 

forests is that forest ecosystems are highly varied and dynamic in 
258 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 47—Secondgrowth forests may differ markedly from one another, even in 

the same region. Influences to a 

forest include:

 Site characteristics—elevation, 

slope, aspect, homogeneity of 

topography, soils, site fertility, 

wetlands, rock outcrops, and 

many other physical features, 

including site modification by 

fire or erosion

 Amount of legacies retained 

from the previous forest

 Time since reorganization

 History of disturbance and 

management after reorganization

 Amount and scale of spatial 

heterogeneity

 Stage of forest development

 Species and life-form diversity

 Resilience and potential for 

development following disturbance

 Health, presence and effects 

of common forest diseases and 

pests

 Overall biocomplexity

structure and composition and in the patterns they form on landscapes (Foster et al. 1996). All ecosystems studied have exhibited 

some responses to past human activity. The rate of change in disturbance processes and associated ecosystem attributes was greatest 

in the historical (not contemporary) period, and many present-day 

old-growth forests comprise anomalous or unique assemblages relative to those of their historical counterparts. Another way of saying 

this is that those old-growth forests that survived when the majority 

were destroyed may have been unusual in their character, their location, or both. Old-growth forests today represent adaptations to past 

environments, including human activities, and are not necessarily as 

well-adapted to future environmental conditions—but might well 

be highly adaptive, owing to their biodiversity. Old-growth forests 

in the Pacific Northwest at best represent less than 6,000 years of 

existence in a time of continuing climate change (Brubaker 1991). 

Thus, their adaptiveness probably is not a result of tight coevolution 

of species over the long term in a stable environment but rather successful self-organization that allowed accumulation of biomass and 

biocomplexity. Across North America, human activities on regional 

to local scales with various direct and indirect impacts on ecosystems, altered climate and cloud and precipitation chemistry, eliminated native species (e.g., passenger pigeons, deer, elk, moose, and 

beaver—all of which influence some forest processes), introduced 

exotic species, including pathogens (e.g., chestnut blight, Dutch elm 

disease, beech bark disease, hemlock wooly adelgids, white pine blister rust), and changed fire regimes. Thus, to be effective, strategies 

for the preservation, management, and restoration of old growth or 

for the conservation of nature in general must be based on acceptance and anticipation of change (Foster et al. 1996). Comparisons 

of natural forest and second-growth forests deliberately shaped by 

silviculture have repeatedly illustrated that conventional silviculture 

does not mimic natural disturbances, promote the same developmental processes that occur naturally, or produce resilient ecosystems with high capacity for adapting to change (Bergeron et al. 1999, 

Carey 2003a, Price et al. 1998). Not only is a new forestry needed, 

but managers must look beyond stands and landscapes to the region 

and to the globe if planning is to be reasoned.

Exogenous Disturbances

Earth is first and foremost a “fire planet” in which an oxygen-rich atmosphere and carbon-based living organisms 
C H A P T E R 7 From Ecology to Forest Management 259

To be effective, 

strategies for the 

preservation, 

management, and 

restoration of old 

growth or for the 

conservation of 

nature in general 

must be based on 

acceptance and 

anticipation of 

change.

Figure 48—Red and blue huckleberry can be found growing side by 

side on the Olympic Peninsula. Photo 

by T. Wilson.

regularly conspire to create conditions that make combustion and widespread conflagration a recurrent, indeed inevitable fact of life (Cronon in Pyne 1997: ix).

When people think of forest fires, they usually think of wild 

(unplanned and unmanaged) fire. But, the history of human use of 

fire is long and astounding. Fire has been used purposefully, indiscriminately, commonly, and frequently. Much of the Earth’s biological diversity has resulted from the presence of people and their use 

of fire. Fire also provided the means by which people claimed nature, 

rendered it habitable, and refashioned it into pastoral and agricultural landscapes worldwide (Pyne 1997). Human use of fire over 

the ages purposefully shaped the subsequent biotic communities in 

North America, from the southeastern pine parklands to the interior prairies of Kentucky to the prairies and oak woodlands and savannas of western Washington (Pyne 1997, Thysell and Carey 2001b, 

Tveten and Fonda 1999). But conversion of forest to grazing and 

agricultural purposes was not the only use or cause of forest fires. 

The interaction of geologic events, climate change, natural forest fire 

regimes, indigenes’ purposeful use of fire, accidental and malicious 

use of fire by indigenes and settlers from the Eastern United States, 

fires resulting from careless logging practices, fires resulting from 

the construction and operation of railroads, forest management and 

fire exclusion, and arson reshaped many forested landscapes and 

their biotic communities, particularly in the inland Northwest, but 

even in the Pacific Northwest (Pyne 1997). 

Long before settlers from Europe arrived, indigenous peoples 

managed landscapes and maintained particular biotic communities across North and Central America with deliberate use of fire 

(Krech 1999, Pyne 1997, Wright 1992). Settlers from the Eastern 

United States found the landscapes managed by indigenous peoples 

in the Pacific Northwest (Oregon’s Willamette Valley and Washington’s Puget Trough) particularly attractive. The first U.S. settlers in Washington usurped, for their own agricultural purposes, 

the prairie, woodland, and wetland mosaics managed with fire by 

the Nisqually people in the Puget Trough. The nearby Skokomish 

people of the eastern Olympic Peninsula maintained shrub parklands dominated by Douglas-fir for winter grazing by Roosevelt elk 

and perhaps for berries (fig. 48) and basket material; there is evidence (prairies up to 1,200 hectares) that people on the west side of 

the peninsula did likewise. Coastal indigenes also intensively managed estuaries for root and tuber production (Deur 2002, Turner 

and Cocksedge 2001). Yakama people (and perhaps the Cowlitz, 
260 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Nisqually, and Puyallup) burned subalpine forest on Mount Rainier 

to push back the forest and maintain parklands for their berries and 

support of deer, elk, and mountain goats. The Calapooya people of 

the interior valleys of western Oregon used fire to maintain prairies 

and oak woodlands and to shape the adjacent conifer upland forests of the Coast and Cascade Ranges, perhaps again for grazing by 

wild ungulates, oak woodlands, and parkland berry fields. Numerous 

plants that once thrived in the managed natural-cultural mosaics 

of the Pacific Northwest Amerindian cultures are now threatened 

by the subsequent introduction of exotic plants and the continuing 

land use changes of an ever-growing U.S. population (Carey 2002a, 

Thomas and Carey 1996, Thysell and Carey 2001b). Farther south in 

the Sierra Nevada, the Nisenan community managed the forest with 

fire for 2,000 years (along with lightning-ignited fires in drought 

years) for hunting grounds and cordage until they were decimated 

by introduced malaria and dislocated and persecuted by gold miners 

in the mid-19th century (Stephens and Collins 2004). Subsequent 

mining, grazing, logging, and, finally, fire suppression produced 

markedly different fire regimes and forest conditions. Now conservationists debate about desirable future conditions for these forests, 

with increasing doubt about natural variation concepts based on historical ecology.

Of all the temperate and tropical forests of North and Central 

America, it is likely that the low- to mid-elevation old-growth forests of the Pacific Northwest are among the least affected by indigenous peoples (Pyne 1997). Northwestern coastal forests with high 

annual rainfall in fall, winter, and spring are relatively fire-resistant, 

and the trees grow too large to be razed by stone-age people or even 

preindustrial iron-age people. In any case, dry summers and lack of 

domesticated grains and root vegetables limited opportunities for 

farming; indeed, it appeared carbohydrates may have been more 

limiting to Pacific Northwest indigenes than protein or fat, given 

abundant, salmon, deer, and elk and the considerable time they spent 

harvesting and drying berries, camas roots, and tubers of wetland 

plants. Much of the temperate forests of the Eastern United States 

and forests in Central America had been changed into croplands, 

woodlands, and savannas well before the arrival of European settlers. Fires, however, were rare in northern New England, where 

windstorms, small and large, were major stimuli of natural change 

(Ziegler 2002). Fire-return intervals were 1,000 years or more in the 

Adirondack Mountains of New York. The spruce-beech-fir-hemlock-birch forests of northeastern Maine were in a climax stage in 

the early 19th century with evidence of a natural fire-return interval 
C H A P T E R 7 From Ecology to Forest Management 261

of 800 to 1,150 years (tree lifespans less than 300 years) (Lorimer 

1977). But just to the south, fires were common in western Maryland old-growth oak forests from 1615 to 1958—42 fires with a return interval of 8 years (Shumway et al. 2001). Catastrophic fire-return intervals in the Pacific Northwest were long as well but variable. 

For example, fire frequency in mountain hemlock forests of southwestern British Columbia, as well as in much of the Pacific Northwest, varied continuously over the last 11,000 years, linked to climate 

change via large-scale atmospheric patterns (Hallett et al. 2003). 

There has been continuous climate change in North America since 

the last major ice age (Pielou 1991), even the last 2 million years 

(Tausch et al. 1993). Catastrophic fire-returns intervals have been as 

short as 150 to 300 years in wet mountain hemlock forests, and 230

to 240 years in the Oregon Coast Range and in southeastern British 

Columbia montane spruce forests, and as long as 1,200 to 2,400

years in coastal British Columbia mountain hemlock and western 

hemlock forests (Hallett et al. 2003). About 20 percent of very wet 

hypermaritime forests and very wet maritime forests of Vancouver 

Island, British Columbia, have gone more than 6,000 years (up to 

12,000 years) without fire; forest on terraces have gone 4,400 years 

without fire, forest on hills have gone 740 years without fire, but all 

forest on south-facing hills all burned within the last 1,000 years 

(Gavin et al. 2003). These almost fire-free forests are marked by 

ubiquitous gaps and tree replacement rates of 35 to 390 years. Otherwise, fire is nearly universal in western North America, but marked 

by heterogeneity in regimes and heterogeneity internal to individual 

fires (Lertzman et al. 1998, Wimberly 2002) (fig. 49). There is substantial variability in fire intensity even in the absence of underlying 

ecological or physical patterns (Wright and Agee 2004). Even modest temporal variability in fire frequency can induce significant variation in forest age structure over time. Openings caused by fires differ from a low of 0.03 to 0.3 hectare in southwestern ponderosa pine 

forests to 0.8 to 2.7 hectares in red fir/Douglas-fir forests to more 

than 3,200 hectares in Oregon mountain hemlock and to more than 

10,000 hectares in conifer forests in Idaho, Washington, Oregon, 

and Alaska (Agee 1998). Fire severity ranges from high in subalpine 

fir, Pacific silver fir, western hemlock, and Douglas-fir forests; to 

moderate in mixed-conifer/mixed-evergreen, dry Douglas-fir, and 

red fir forests, and low in mixed-conifer, ponderosa pine, and oakwoodland forests. In other words, fire severity is highest where it is 

wettest and coolest, fires are infrequent, and extreme weather sets 

the stage. And fires are lowest where it is warmest and driest and 

vegetation is adapted to frequent fires; but the extent and severity of 
262 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 49—A forest fire in 

Montana’s Bitterroot Valley during the 

2000 fire season. Photo by J. McColgan, Alaska Fire Service, Bureau of 

Land Management.

forest fires is not necessarily well correlated. Thus, fire regimes can 

be characterized as low-severity/nonlethal, mixed-severity/moderately lethal, and high-severity/lethal. For example, in unlogged ponderosa pine-Douglas-fir forest in the Colorado Front Range, evidence was found of light fires in 1534, 1686, 1700, 1775, 1841, and 

1963 and moderate-intensity fires in 1587, 1631, 1723, and 1851. The 

historical landscape was less densely forested than today; forests had 

low densities of trees, open canopies (10 to 30 percent canopy cover), 

and openings over 15 to 25 percent of the landscape; some dominant 

trees persisted for 500 to 600 years. However, at higher elevations in 

Colorado (2,100 to 3,000 meters in Rocky Mountain National Park), 

crown fires were part of the natural disturbance regime (Ehle and 

Baker 2003). Of 103 historical disturbance events, 97 percent were 

due to fire and 7 percent of those were high-severity fires (70 percent were low-severity fires). At least one crown fire occurred within 

300 years in seven of the nine plots studied. Crown fires produced 

dense even-aged stands that, because of subsequent surface fires, developed into less dense uneven-aged stands after 200 to 300 years. 

Thus, the fire ecology of high-elevation ponderosa pine forests in 

Colorado is somewhat different than that in the lower elevation 

Front Range and those in the Southwest. Historical fire produced a 

mosaic landscape in Colorado just as it did in the Oregon Coast 
C H A P T E R 7 From Ecology to Forest Management 263

Figure 50—The effects of pine bark 

beetle on a forest near Fort Collins, 

Colorado. Photo by A. Carey.

Ranges (Wimberly and Spies 2001) despite differences in intensity 

and frequency. But logging, grazing of livestock, fire suppression, 

and urban encroachment have produced young second-growth forests that are densely stocked and that have excessive fuel loads resulting in unusually severe fires and widespread insect epidemics 

(Kaufmann et al. 2003) (fig. 50). In the 58-million-hectare interior 

Columbia River basin (46 percent forested), physiographic diversity, 

the interaction of three major air masses, and summer drought produces at least 22 forest types with fire-return intervals ranging from 

6 to 419 years (with a mean of 51 years) (McKenzie et al. 2000b). In 

addition to seasonal and annual droughts, fires were correlated with 

multiyear climatic signals, such as the Pacific decadal oscillation, until the 20th century when wet-weather decades, logging, fire suppression, and perhaps changes in burning practices of Native Americans, reduced fire frequencies (Hessl et al. 2004, Wright and Agee 

2004). Spatial patterning in ponderosa pine forests in the Columbia 

basin differs with site—cool, dry grass and warm mesic sites have 

smaller clumps and higher densities of trees than hot, dry, shrub 

lands that exhibit strong clumping historically with limited seedling 

establishment (Harrod et al. 1999, Wright and Agee 2004). Larger 

openings between clumps of trees may produce increased fuels for 

fire, which when low in intensity, may favor seedling establishment. 
264 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Historically, these forests had patch sizes of 0.09 hectare (with a 

range of 0.0005 hectare in mesic sites to 0.2 hectare in xeric sites) 

similar to 0.06 to 0.13 hectare in the Southwest and 0.02 to 0.29

hectare in eastern Oregon. The density of residual large trees (greater than 50 centimeters d.b.h.) was highly variable, 5 to 9 trees per 

0.5-hectare plot (a maximum of 19 trees per hectare), whereas fire 

exclusion, grazing, and timber management have produced more 

homogeneous stands with 50 trees per hectare, highly vulnerable to 

bark beetle attack and crown fires. Presettlement forests were at low 

risk to crown fire and bark beetle attack, suggesting a relatively finescale pattern of 0.1 to 0.3 hectare would be an appropriate grain size 

for managed ponderosa pine mosaics. Land use changes and management practices have affected these forests as profoundly as those 

in Colorado (Harrod et al. 1999, Tiedemann et al. 2000). There is no 

such thing as a forest free of fire, and when management has excluded fire then the option of “letting nature take its course” no 

longer constitutes a sustainable conservation strategy (Agee 2002). 

Climate, environment, and people interact to produce both disturbance regimes and forests of varying character.

The lack of upland forest destruction by indigenes and long firereturn intervals do not mean that Pacific Northwest forests developed free of human influence. Significant variation in the climate of 

the United States was due to human activities in Europe and Asia. 

Eurasians had destroyed their own forests relatively rapidly 5,000

to 8,000 years before the present, beginning with slash-and-burn 

agriculture, then irrigation of rice fields, followed by development of 

iron technology, use of charcoal for fuel, harvests of timber for ship 

building, and urban development—even to the point of affecting climate through agricultural production and loss of forests (Ruddiman 

2003). This period of Eurasian deforestation and induced climate 

change coincided with the establishment of “modern” forest types 

in the Pacific Northwest (Brubaker 1991). Germans invaded Slavic 

countries to get wood in 1,000–1,100 AD (Farrell et al. 2000). Great 

Britain denuded Ireland of trees for naval purposes; reforestation is 

beginning only now. Even European boreal forests were destroyed 

(Berglund 1991). Of course, boreal forests are fire-adapted forests, 

with decadal surface fires and crown fires by the century, depending on degree of drought, dry lightning, and wind, even without 

human use of fire (Pyne 1997). Thus, boreal forests are more easily 

burned than Pacific Northwest forests. The only extant temperate 

forest in Europe that has a natural stand structure is the Białowieza 

Primeval Forest (primarily a Tilio-Carpinetum mesic forest) in Poland (Bobiec 2002). As in most old-growth temperate forests, this 
C H A P T E R 7 From Ecology to Forest Management 265

Sidenote 48—“We are an Ice 

Age creation but a fire creature” 

(Pyne 1997).

forest shows an irregular distribution of legacy (or pioneer cohort) 

trees; large amounts of coarse woody debris (87 to 160 cubic meters 

per hectare) and decadence (25 percent of total aboveground biomass); spatial heterogeneity or patchiness; complex avian and mammal communities; relictual invertebrates, fungi, and epiphytic flora; 

and evidence of successive disturbance by fire, storms, and insect 

outbreaks. The destruction of European forests had ramifications for 

Pacific Northwest forests by stemming glaciation (sidenote 48) and, 

when bubonic plague decimated European populations, it led to reduced carbon dioxide emissions, reforestation, carbon sequestration, 

and to the Little Ice Age (1300–1900 AD)—the climatic period in 

which the contemporary Pacific Northwest old growth developed. 

Undoubtedly there were differences in Pacific Northwest climate, 

disturbance regime, and the subsequent development of structure 

and composition of these forests from what would have occurred if 

deforestation followed by plague had not occurred in Europe. For 

example, palynological review of 5,000 years of disturbance and vegetation change revealed only two major fires, but a rise in western 

hemlock pollen began 1,000 years ago in the vicinity of the Queets 

River on the western Olympic Peninsula, in response to a cooling 

climate during the Little Ice Age (Greenwald and Brubaker 2001). 

The history of direct and indirect interactions of people, prevailing climate regimes, continuous climate change, and rare geologic 

and weather events suggest landscape patterns of the past are not of 

particular value in designing landscapes of the future. The profound 

impacts of land use change and forest management of the last century suggest that, even if climate was predictably cyclic and modern people could be removed from a region, it is unlikely we could 

re-create the biotic communities of the past (Carey 2003a, 2003c; 

Tiedemann et al. 2000). 

What is known for certain is (1) climate will change; (2) human populations and their impacts on local, regional, and global 

environments will increase for the indefinite and foreseeable future; 

and (3) burgeoning populations and environmental degradation in 

developing countries (as happened in Europe historically) will have 

significant social, economic, and environmental impacts not only in 

the Pacific Northwest, but also around the globe. The Pacific Northwest is downwind of China. Already we receive substantial deposits 

of Gobi Desert dust. China’s rapid economic development portends 

huge increases in burning of fossil fuels; there will be environmental 

ramifications in the Pacific Northwest. Furthermore, low- to midelevation forests of the Pacific Northwest are subject to infrequent, 

unpredictable catastrophic fires, major windstorms, earthquakes, 
266 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 51—Adult spruce beetle. 

Photo by D. McComb, USDA Forest 

Service. Spruce beetle damage. Photo 

by W. Ciesla, Forest Health Management International. An adult spruce 

beetle with eggs. Photo by E. Holsten, 

USDA Forest Service.

tsunamis (Everham and Brokaw 1996, Henderson et al. 1989, Sinton and Jones 2002, Stathers et al. 1994), and volcanoes (Franklin 

and MacMahon 2000). Climatically based disturbance regimes will 

change. Biological disturbances are becoming of increasing importance. From 1920 to 1989, spruce beetles killed most of the spruce 

on 850,000 hectares in south-central Alaska; in the 1990s, spruce 

beetles killed spruce on another 800,000 hectares (Ross et al. 2001) 

(fig. 51). Interior Northwest forests now seem particularly vulnerable 

to catastrophic loss owing to interactions of insect pests, disease, and 

fire as a result of complex historical contingencies including land 

use changes, drought, fire exclusion, grazing, introduction of exotic 

species, and homogenizing timber management. In other regions of 

North and Central America, fire, hurricanes, and tornados regularly 

cause catastrophic destruction of forest. Continent-wide, the threat 

of forest destruction (or at least substantial modification) from introduction of exotic diseases and insect pests and spread of existing 

ones, such as Swiss needle cast, sudden oak death fungus, Asian 

longhorned beetles, European pine shoot beetles, and emerald ash 

borers, is not only real but a major event is probable. Hemlock wooly 

adelgids are causing severe problems in the 11 eastern states comprising the range of eastern hemlock. The worst recorded outbreak 

of southern pine beetles affected 4.9 million hectares in 2001 and 

5.7 million hectares in 2002 (USDA Forest Service 2003). Mountain pine beetles have shown a dramatic increase from 344,000 to 

647,000 hectares affected in 2002. Spruce beetles have increased in 

Arizona, Colorado, Montana, Utah, and Wyoming. Unregulated 

logging continues in underdeveloped countries, as does conversion 

of native forests to plantations of exotic species and forest land to 

agricultural uses. Thus, in our domestic policy, it may be beneficial 

to emphasize conservation and general sustainability. In our foreign 

policy, it may be beneficial to emphasize sustainable development 

and social justice. But, in the least, we must manage our forests such 

as to maximize their capacity to adapt to an ever-changing environment and allow us to move toward a self-sustaining future.
C H A P T E R 7 From Ecology to Forest Management 267

Endogenous Disturbance

After catastrophic disturbance, the developmental endpoint in Pacific Northwest Douglas-fir forests is the “pioneer cohort loss stage” 

at 800 to 1300 years. Strong spatial patterning (horizontally and vertically) is characteristic of these forests (Franklin et al. 2002). This 

patterning occurs despite apparent marked differences in degree of 

stocking in the early stages of forest development (Poage and Tappeiner 2002; Winter et al. 2002a, 2002b). Some of this patterning is 

the result of occasional (say decadal to multidecadal) small- to intermediate-scale exogenous disturbances such as fires, thunderstorms, 

rainstorms, windstorms, ice storms, snowstorms, disease epidemics, 

and widespread insect outbreaks. But significant patterning is a result of various endogenous processes including density-dependent 

mortality owing to competition (suppression of subordinate trees 

by dominant trees), endemic disease spread, and insect attack; density-independent accidents and tree fall; symbioses and local biotic 

interactions; local flooding and mass-wasting (landslide) events; and 

other local environmental changes. Tree death from heart and root 

rots is common (Carey et al. 1996b, Hennon 1995, Holah et al. 1993, 

Huff 1995, Parks and Shaw 1996, Thies 1999, Thies and Sturrock 

1995). Root rots can become epidemic in the first 50 years of forest 

development, reducing stem density, creating gaps, and promoting 

understory development (Thysell and Carey 2000). However, competition is the major cause of death in most conifer forests under 

100 to 150 years old (Carey et al. 1999b, 1999d; Franklin et al. 1987). 

Heart rots play multiple ecological roles in forests from providing a 

substrate for excavation of cavities by woodpeckers (fig. 52), to hollow trees for bears and Vaux’s swifts, to weakening boles, contributing to bole breakage, tree fall, and gap formation. Bole breakage is 

a leading cause of death of trees in older forests. Snapping of boles 

and standing death constitute more than 75 percent of gapmakers in 

the Pacific Northwest; uprooting accounts for 21 percent (Lertzman 

et al. 1996). Mechanical damage by falling trees to other trees accounts for 15 percent of mortality in old forests (Franklin et al. 1987). 

In interior (Idaho and Montana) western hemlock forests, rots can 

become excessive in 100 to 120 years; in British Columbia, decadence 

in western hemlock prevails at 225 years. In old-growth hemlockspruce forests, more than 30 percent of the gross volume of wood is 

affected by rot; 50 percent of the wood volume in old western redcedar trees is rotten; 80 percent of old-growth Douglas-firs have heart 

rot (Hennon 1995). Heart rot fungi infects vigorous Douglas-fir at 

an early age (say 50 years) through small twigs and eventually leads 
268 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 52—The importance of 

heart rot—a pair of pilated woodpeckers nest in an excavated tree 

cavity. Photo courtesy of USDA Forest 

Service.

to tree death more than 150 to 170 years later contributing to loss of 

the pioneer cohort of Douglas-fir and their replacement by shadetolerant species beginning at 300 to 400 years in the life of the forest. 

Canopy trees dying while standing, boles breaking, and uprooting 

are common causes in many forests of North and Central America, 

producing a spatial-temporal mosaic of patches in different stages of 

recovery following the disturbance created by the falling tree (Putz 

et al. 1983). As a result of this variety of noncatastrophic exogenous 

and small- to intermediate-scale endogenous disturbances, a variety 

of canopy patterns can form, ranging from continuous closed canopy punctuated at 40 to 150 meters by 1- to 2-meter-wide low-density 

gaps (20 percent open) to 2- to 6-meter-wide, low-density gaps (40
C H A P T E R 7 From Ecology to Forest Management 269

Figure 53—Distributions of maximum air temperature on June 7, 2002,

(cool day), in four study plots on the 

Olympic Peninsula. Relative temperature value at each point is indicated by 

the size of the circle. Axes numbers indicate meter location on plot. Control 

plots are on left, and plots treated with 

variable-density thinning (VDT) are on 

right (Aukema 2003a).

percent open) in young forests to 2- to 30-meter-wide gaps (more 

than 60 percent open) 40 to 110 meters apart in old forest (Bradshaw 

and Spies 1992). In southwestern Oregon, 50 percent of old forest 

had less than 50 percent canopy closure, indicating a gap; these gaps 

were 70 to 80 meters apart (Carey et al. 1999b). In coastal British Columbia, as forests age, canopies become more open and more 

heterogeneous (Frazer et al. 1998, Hedberg and Blackwell 1998); 56

percent of old forest area is affected by canopy openings, with 30

percent of the area actually in gaps (Lertzman et al. 1996). Gaps are 

generally less than 0.1 to 0.2 hectare (Carey et al. 1999b, Spies and 

Franklin 1989, Spies et al. 1990). Additional patterning is caused by 

topoedaphic features, especially wetlands and small streams (Carey 

1988). The influence of canopy changes on microclimate varies with 

gap size, season, and degree of understory and midstory development (Benton 1998, Gray et al. 2002). Variation can be extreme in 

large gaps, with hot dry conditions at the northern end (greatest 

exposure to sun) and cool, moist conditions at the southern end, 

which may remain shaded by the adjacent trees. Research has shown 

that experimentally induced fine-scale canopy heterogeneity can result in a patchy understory microclimate that maintains the range 

of conditions in untreated stands while adding to the diversity of 

patches available (fig. 53). This phenomenon is not only prerequisite 

to development of habitat breadth (Carey et al. 1999b) but also may 

increase the ability of second-growth forests to support year-round 

resident wildlife (Haveri and Carey 2000).
Table 22—Interactions of climate, fire frequency, and fire intensity produce different types of forests 

Frequency of light 

surface fires (in years)

Frequency of intense (crown and severe surface) fires (in years)

25–100 100–500 500–1,000 >1,000

<25  Jack pine barrens

 Aspen parkland

 Ponderosa pine

 Southern pine

 Bur oak savanna

 Giant sequoia

25–100  Red/white oak

 White/red pine

>100  NW boreal forest

 Jack pine/spruce 

 Spruce/fir/birch

 NE boreal forest

 Spruce peatlands

 Lodgepole pine

 Interior Douglasfir 

 Coastal Douglasfir

 Western hemlock

 Sitka spruce

 Sugar maple/

basswood

 Sugar maple/

hemlock

Source: Frelich 2002.

270 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 49—Lessons from 

the 1998 Yellowstone National 

Park (YNP) fire (Turner et al. 

2003):

 Many northern coniferous 

forests, like some in YNP,

are characterized by natural 

stand-replacing fires that are 

infrequent (return intervals of 

100 to 500 years), but severe.

 Climate is the primary driver 

of stand-replacing fire regimes, 

with variation in fuels less 

important.

 Catastrophic disturbance 

influences plant population 

structure, genetics, and evolution.

 Spatial heterogeneity resulting 

from catastrophic fire is the 

rule, not the exception.

 Fires and fire regimes are not 

all the same, thus wildfire 

management must be site 

specific.

Spatial complexity also characterizes forests in regions with 

chronic low- to moderate-intensity disturbance regimes incorporating wildfire, such as ponderosa pine forests, mixed-conifer forests, 

and southeastern longleaf pine, flooding in Neotropical riverine 

forests, or wind, such as the Nothofagus forests of Tierra del Fuego 

(Franklin et al. 2002) (sidenote 49). Complexity is the major factor determining mammalian diversity in South American forests, as 

a consequence of preinteractive niche diversification (August 1983, 

Grelle 2003, Mares et al. 1986). Spatial heterogeneity makes construction of models predictive of fire frequency in the interior Columbia basin difficult; large amounts of data at fine resolution are 

required (McKenzie et al. 2000b). In the absence of human activity, 

small- to intermediate-scale disturbances result from the interaction of weather, other agents of disturbance, and forest structure and 

composition that are consequences of past small- to large-scale disturbances: drought creating stress leading to defoliator insect outbreaks; a dry-lightning storm igniting fires (table 22); a wind event 

causing blowdown; weather patterns leading to periodic intense 

grazing by grasshoppers, microtine rodents, rabbits, hares, deer, elk, 

moose, and bison (Frelich 2002). 

The frequent and recurring nature of small- and intermediatescale disturbances and their interactions with the ecosystem suggests they could be considered integral to the system rather than 

forces exogenous to but impinging on the system. For example, the 

2-year spruce budworm exhibits a 32- to 45-year periodicity in defoliating spruce and fir resulting in growth reduction and understory release in high-elevation and high-latitude spruce-fir forests 

(Parish and Antos 2002). Frequent low-intensity fires on the east 
C H A P T E R 7 From Ecology to Forest Management 271

Most forests 

maintain mosaics 

in their late-seral 

stages with a grain 

size in the range 

of about .1 to 1. 

hectare, probably 

with a central 

tendency of . to 

. hectare.

slopes of the central Washington Cascades exhibit negative feedback through fuel reduction (Wright and Agee 2004). In the boreal 

forests of eastern Canada, the spruce budworm may kill balsam fir 

in the canopy and release seedlings in the understory, controlling 

canopy turnover in the absence of fire. When human activities have 

promoted overly dense, stressed stands of trees, buildup of fuels 

for forest fire, and overly simplified forests, what would have been 

small- to intermediate-scale more-or-less endogenous disturbance 

can become individually magnified or jointly cascade into catastrophic destruction of the forest. Various management techniques 

can be used to reduce the risk of catastrophes. Small-scale timber 

harvests (patch cuts, partial cuts, and thinnings) can be useful in 

forests subject to small- and intermediate-scale disturbances. They 

can also be used where moisture stress is high to promote advance 

regeneration under the shelter of a partial canopy while maintaining 

forage for wildlife and decreasing potential for frost damage and 

erosion (Kneeshaw et al. 2002). Prescribed fire is useful in maintaining biotic integrity and promoting resilience in fire-adapted forests. 

Under certain circumstances, grazing also becomes a use that can 

contribute to resilience. 

Forests subject to frequent light to moderate disturbances form 

mosaics. Patches in these mosaics are often mistaken for independent stands of trees, whereas in reality, they constitute a late-seralstage mosaic (Franklin et al. 2002). Despite variety in disturbance 

regimes, most forests maintain mosaics in their late-seral stages with 

a grain size in the range of about 0.1 to 1.0 hectare, probably with 

a central tendency of 0.2 to 0.5 hectare. For example, White (1985) 

found establishment of ponderosa pine was infrequent in Arizona, 

maybe requiring 40 years, with stems aggregated in groups of 3 to 

44 trees, 0.02 to 0.29 hectare; ages within groups were variable, with 

the most homogeneous having a range of 33 years and the least 

with a range of 268 years. In that area, it appeared seedlings established after the death of one to two large trees in a small area of 

intensive fire in an otherwise low-intensity fire area. Cooper (1960) 

reported similar aggregations in southwestern ponderosa pine but 

with a narrower range of ages within them. In the markedly different old-growth Douglas-fir forests of southwestern Oregon, the 

grain of mosaics was still 0.2 to 0.5 hectare including in Western 

Hemlock Zone forests and Mixed-Conifer/Mixed Evergreen Zone 

forests (Carey et al. 1999b). This scale of patchiness is widespread 

(Canham et al. 1990). 

In general, forest development following catastrophes consists of 

gradual change and envelopment that result in diversity, complexity 
272 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 50—Windthrown 

versus clearcut—what is the difference after 70 years (Price et al. 

1998)? Wind left behind legacies 

that led to heterogeneity when 

compared to clearcutting:

 Coarse woody debris—0.09

cubic meter per square meter 

versus 0.04 cubic meter per 

square meter

 Gaps—17- by 90-meter 

transect versus 2- by 90-meter 

transect

 Veteran trees larger than 60-

centimeter diameter at breast 

height (d.b.h.)—11 versus 4

 Snags larger than 20-centimeter d.b.h.—20 versus 5

 Range in live tree d.b.h.—127

centimeters versus 80 centimeters

 Arboreal macrolichens—15

taxa versus 10 taxa

 Percentage of fallen trees 

larger than 70 centimeters—20

percent versus 0 percent

of structure and processes, and production of large structures, some 

of which persist through subsequent intermediate and catastrophic 

disturbances and assist in recovery of the ecosystem (sidenote 50). 

For example, populations of most vascular plants quickly recover 

to original levels even after clearcutting and burning, although on 

severely burned sites, some species may experience local extinction 

(Halpern and Spies 1995) and grasses and annual forbs (including exotic species) may be more common, and perennial ferns and 

shrubs less common, than after wildfire, owing to soil disturbance 

(Peltzer et al. 2000). But as the tree canopy closes and light, water, and nutrients are funneled into producing wood, plant diversity 

may be suppressed for over 20 years (Halpern and Spies 1995, Long 

1977), and abundance and diversity may remain low for 60 years or 

more (Thysell and Carey 2000). Even the seeds of native plants may 

disappear from the soil seed bank (Halpern et al. 1999, Lezberg et al. 

1999, McKenzie et al. 2000a). Biomass accumulates rapidly across a 

chronosequence of 3 to 9, 30 to 40, 65 to 100, and over 200 years in 

various forest types in coastal Pacific Northwest forests, for example, 

3.5, 232, 463, and 687 megagrams per hectare (Mg/ha) (1 megagram 

= 1,000,000 grams) in wet western hemlock forest and 0.6, 143, 423, 

and 586 Mg/ha in dry Douglas-fir (Hedberg and Blackwell 1998). 

Tree density and biomass accumulation, however, has high local 

variation, even in 140-year-old coastal Oregon spruce-hemlock forests, for example 462 to 750 Mg/ha (with 144 to 155 Mg/ha in coarse 

woody debris) (Acker et al. 2000). Coastal Oregon forests may store 

up to 1,127 megagrams of carbon per hectare (Mg C/ha), coastal 

Washington forests, 307 Mg C/ha less. Similarly, Oregon Cascade 

Range forests store 75 Mg C/ha more than Washington Cascade 

forests. Overall, Pacific Northwest forests store 338 Mg C/ha—the 

highest of any forests in the world; 1 percent is in understory vegetation, 6 percent in the forest floor, 10 percent in woody debris, 15 to 32

percent in the soil, and 53 to 67 percent is in trees. Eastern Oregon 

forests, however, store only 195 Mg C/ha (Smithwick et al. 2002). 

Coarse woody debris can be especially variable in space and time 

(Carey and Harrington 2001, Carey and Johnson 1995, Carey et al. 

1999b, Wells and Trofymow 1998). Coarse woody debris cover can 

vary fivefold (5 to 24 percent, averaging 13 percent) in old growth 

and threefold (5 to 16 percent, averaging 8 percent) in second growth 

on the Olympic Peninsula versus 10 ± 2 percent cover in old growth 

and 4 ± 1 percent in second growth in the Oregon Coast Ranges—a 

twofold difference in second growth between regions (sidenote 51). 

On southern Vancouver Island, coarse woody debris ranged from 

17 to 38 Mg/ha (55 to 149 square meters per hectare) in Douglas-fir 
C H A P T E R 7 From Ecology to Forest Management 273

forest to 65 to 199 Mg/ha (307 to 636 square meters per hectare) in 

western hemlock-western redcedar forest—a two- to threefold variation within forest type and fivefold variation between forest types 

(Wells and Trofymow 1998). After reorganization, alternative stable 

states are possible, especially in managerially simplified forest—for 

example, the competitive-exclusion and the biomass-accumulation 

stages; development beyond these stages may require significant exogenous disturbance. Silvicultural treatments that foster spatial and 

temporal diversity of resources and environments can be effective in 

maintaining not only plant species (Carey and Johnson 1995; Carey 

et al. 1999b, 1994; Halpern and Spies 1995; Thomas and Carey 1994; 

Thysell and Carey 2001a) but also structural elements and animal 

communities. Without successive exogenous disturbances, change 

may be slow or rapid depending on the stage that was set, the legacies that were retained, the environmental heterogeneity inherent to 

the biotope, and internal disturbances such as root diseases and tree 

fall. The net result of successful community development is symbiosis, nutrient conservation, stability (not necessarily equilibrium), and 

decreased entropy. 

Accumulation of biomass is fundamental to forest ecosystem 

development (Bormann and Likens 1979)—it provides resistance to 

change with minor disturbance and sets the stage for reorganization 

conditioned by legacy retention with catastrophic disturbance. This 

accumulation of biomass occurs in the form of various living plants, 

their exudates and litter fall, and dead and decaying plants and plant 

parts, down to carbon in the soil food webs (table 23). 

Forest development, throughout temperate forests, incorporates 

multiple other processes that are variously dynamic and stochastic, 

but also many that are predictable and probable (Bobiec et al. 2000, 

Bormann and Likens 1979, Franklin et al. 2002, Odum 1969) (sidenote 52). The most deterministic process, however, is accumulation 

of biomass; less deterministic are the entry of decay into living trees 

and development of rich epiphytic communities (especially in the 

absence of legacy retention during clearcutting). Forests with rare 

catastrophic disturbances but with chronic intermediate and smallscale disturbances are characterized by spatial heterogeneity, especially horizontal patchiness that develops over time. Note, however, 

that even these processes of generating structural complexity in the 

forest are a subset of broader ecological processes such as fundamental 

physical and chemical processes that contribute to soil development 

and govern nutrient availability and cycling, belowground microbial 

and fungal processes, dispersal, colonization, competition, facilitation, symbiosis, development of habitat breadth, preinteractive niche 
Table 23—Accumulation of biomass is directly related to the elements of forest structure and their spatial patterning

Individual structures  Live trees

 Large-diameter trees

 Large-diameter branches

 Lower canopy tree community

 Ground community

 Standing dead trees (snags)

 Large woody debris (logs)

 Root wads and soil pits

 Soil organic layers

Spatial patterns  Vertical distribution of foliage/canopy

 Horizontal distribution of various elements

 Gaps and antigaps

Source: Franklin et al. 2002.

274 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 51—Coarse woody 

debris (CWD)—How much is 

enough? How many snags and 

fallen trees of various sizes and 

decay classes are necessary to 

maintain full ecosystem function? 

The question has been of intense 

interest for more than 50 years 

(Elton 1966, Hamilton and Cook 

1940). A national symposium on 

snags was held in 1983 (Davis et 

al. 1983) and one on dead wood in 

1999—for which the proceedings 

neared 1,000 pages (Laudenslayer 

et al. 2002). Coarse woody 

debris more than 10 centimeters 

in diameter is difficult to measure because it is not uniformly 

distributed in forests; rather it 

tends to be complexly distributed 

in randomly scattered clumps as a 

result of gap formation and individual large fallen trees of various 

species. In other words, multiple 

processes produce CWD. Trying 

to measure CWD with a few small 

plots almost guarantees underestimates owing to many plots with 

0 values—for example, Rose et 

al. (2001, table 1 [in Johnson and 

O’Neil 2001]) reported very low 

levels of CWD in Pacific Northwest conifer forests compared to 

studies that used more intensive 

sampling. Line intercept methods are preferred but are time 

consuming. There is no consensus 

on what measure to use: percentage cover, volume, or biomass. 

Even when CWD is precisely 

measured, it is difficult to know 

how to apply empirical data on 

the abundance of a structure element of the forest to management 

recommendations. The responses 

of keystone species or keystone 

complexes to CWD can be useful. 

For example, analyzing space use 

by flying squirrels suggests that 

a 10-percent cover of large CWD

diversification, postinteractive niche partitioning, and development 

of emergent properties. The natural time scale of forest development 

is long, perhaps 100 to 250 years in eastern deciduous forests (Bormann and Likens 1979, Carey 1983, Oliver and Larson 1996), 250 to 

750 years in Pacific Northwest forests—the life expectancy of adult 

Douglas-fir—and longer in other forests, for example, more than 

1,000 years in coastal redwood forests in California and western 

redcedar forests on Vancouver Island in British Columbia (Franklin 

et al. 2002, Oliver and Larson 1996). But hundreds or more generations of salamanders, warblers, shrews, mice, squirrels, weasels, and 

spotted owls occur during the life of a long-lived Douglas-fir or 

redwood tree. 

The ecosystem strategy of homeostasis through maximum support of complex biomass structure conflicts with management goals 

of maximizing yield of wood products (Odum 1969) and, especially, 

maximization of net present value from timber production (Carey 

et al. 1999c). Silviculture, however, can be used either as a means 

of maximizing return on investment or as a means of optimizing 

public and private values, including product and biotic-community 

diversification, with gradual change managed by small- and intermediate-scale disturbances on a time scale of about 150 years. Thus, 

silviculture can contribute to simplification or to diversification 

of the ecosystem. With active management, the development of a 

complex biomass structure is not inexorable; management with low 

intentionality can impede or preclude development of diverse ecosystems (Carey 1995, 1998b; Carey et al. 1999b, 1999c). However, 

management of forest ecosystems can accelerate forest development 

(Carey et al. 1996a). 
C H A P T E R 7 From Ecology to Forest Management 275

provides sufficient foraging area 

for truffles of ectomycorrhizal 

fungi for near complete use of 

an area of forest in the Pacific 

Northwest (Carey et al. 1999b). 

In moist forests in Washington, 

however, complex forest-floor 

small mammal communities seem 

to require about 15 percent cover 

of CWD (large and small) to reach 

their potential diversity and abundance (Carey and Johnson 1995). 

This suggests an additional 5 percent cover of smaller CWD would 

help maintain forest-floor function in moist forests. But research 

has shown that CWD does not 

operate independently of other 

forest elements and that dynamics 

are important. The full process of 

decadence from decay in living 

trees, to decaying standing dead 

trees, to decaying fallen trees must 

be kept in mind. A rule of thumb 

for management is to aim for 10

percent cover of large (more than 

50 centimeters in diameter) fallen 

trees in dry to mesic Douglas-fir 

forests and 10 percent cover of 

large and 5 percent cover of small 

CWD in mesic western hemlock, 

Douglas-fir, Pacific silver fir, 

or Sitka spruce forests, beginning with inputs in the form of 

legacies and continuing with each 

silvicultural entry to ensure a 

regular stream of inputs until gap 

formation begins in the late-seral 

stage to eventually recover levels 

of CWD when necessary and then 

to maintain them thereafter.

Accumulation of biomass, living and dead, and in different life 

forms, contributes to niche diversification, an expansion of the niche 

space within the ecosystem—the preinteractive niche differentiation 

(Hutchinson 1957, 1978). This expansion may result in synergism 

through symbiosis and other mutualisms. Other endogenous processes, such as top rot in living trees, also are integral to autogenic 

development of ecosystems and may require managerial stimulus 

in managed second-growth forests. Thus, hypothetically, it is possible to conserve biodiversity in managed forests through planned 

management disturbances and gradual change that expands various 

dimensions of the ecosystem (sidenote 53). Management can maintain dynamic shifting steady-state mosaics at both the level of the 

ecosystem and the level of the landscape within narrower bounds 

than produced over time by natural disturbance regimes. Over time, 

then, conservation of biodiversity and adaptive ecological innovation in response to regional and global change would be achieved intentionally even despite (possibly aided by) frequent uncontrollable 

intermediate disturbances (e.g., disease outbreaks, small-scale fires, 

and windstorms) and rare catastrophes (large-scale windstorms, fires, 

and volcanic eruptions). Simple maintenance of a shifting steadystate mosaic, however, may not be adequate to meet all the goals of 

conservation. Ecological forestry must rest on processes underlying development of structure and composition in complex forests 

(Carey et al. 1999b, 1999c; Franklin et al. 2002; Oliver and Larson 

1996). Beyond legacy retention, reorganization of biotic resources, 

colonization, and establishment of a new forest community after 

catastrophic disturbance, there are four structural processes and two 

compositional processes that constitute the necessary minimum 

subset of processes that must be considered in designing ecological 

forest management (Carey et al. 1999b). These are crown-class differentiation, decadence, understory development, canopy stratification, development of habitat breadth, and niche diversification.

Crown-Class Differentiation

Crown-class differentiation is the achievement of dominance (full 

growing space) by some trees, codominance by others, and subordinance of yet other trees (table 24). It also includes differentiation in 

branches within crowns that occurs as a result of the differentiation 

in crown class among trees. In a densely stocked plantation, trees 

compete with one another through rapid height growth; the one that 

overtops its neighbors wins, and, thus, there is a tendency toward 
Table 24—Crown-class differentiation in young (4– years), mature (–1 years), and old forest (– years) in the Oregon Coast 

Ranges as measured by average densities (trees per hectare) in three 

diameter-at-breast-height (d.b.h.) classes

D.b.h. class Young Mature Old

(in centimeters) (Trees per hectare)

10–49 270 120 27

50–99 30 65 25

>100 2 7 22

Source: Adapted from Carey et al. 1991.

276 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 52—Processes 

leading to structural complexity 

of forests, in general order of occurrence through time (Franklin 

et al. 2002):

 Disturbance and legacy creation

 Establishment of a new cohort 

of trees and other plants

 Canopy closure of the tree 

layer

 Competitive exclusion of 

ground flora

 Lower tree canopy loss and 

death and pruning of lower 

branch systems

 Biomass accumulation

 Density-dependent tree mortality owing to self-thinning, 

wind, disease, and insects

 Canopy gap formation

 Generation of standing dead 

and fallen trees

 Uprooting of trees

 Understory reinitiation

 Establishment of shade-tolerant trees, shade-patch or 

antigap development

 Maturation (achievement of 

maximum height and crown 

spread) of the dominant tree 

cohort

 Canopy elaboration through 

canopy stratification and reestablishment of lower branch 

systems

 Development of live-tree 

decadence

 Development of large branches and branch systems

 Development of rich epiphyte 

communities

 Loss of original dominants

even spacing among dominant trees. When regeneration is moderately dense or patchy in density, trees “forage” and avoid neighbors 

by growing toward areas with high resource availability (less competition from neighbors); thus, in many species, tree crowns are rarely 

positioned directly above the stem. Crowns are displaced toward gap 

centers, especially subcanopy, and crown depth is greatest toward 

gaps (Muth and Bazzaz 2002). As trees get large and achieve dominance, the largest branches within their crowns may approach an asymptotic maximum length (around 9 meters in old Douglas-fir) and 

break, or die back (Ishii et al. 2000a, 2000b). Epicormic branches 

may then grow to replace the dead or dying branches, especially in 

the lower crown. Three crown patterns can result in Douglas-fir: 

mature crown, old crown, and stressed crown. The mature crown 

has an increasingly wider range of branch diameters toward the 

lower crown with the diameter distribution of dead branches constant; overall, the crown shape is conical with larger branches lower. 

The old crown has a few large-diameter branches, with the larger 

branches in the upper crown, and many dead branches. The stressed 

crown has small-diameter branches with only a few live branches 

and limited crown depth owing to insect or pathogen attack. In the 

lower crown of live old trees, nearly 50 percent of shoots and foliage 

are epicormic; in the mid and lower crown, reiteration of shoot cluster units maintains the remnants of large, broken branches and helps 

prolong the tree’s lifespan (Ishii and Ford 2001). It is remarkable 

that median size mid-crown branches in a 400-year-old tree may 

be more than 20 centimeters in diameter, more than 8 meters long, 

and more than 150 years old. The effects of this crown elaboration 

on the ecosystem are profound (Carey 1996). Not only are nest sites 

for spotted owls, marbled murrelets, and northern goshawks thus 

produced, but variation in branch size and health allow niche partitioning by cavity-using birds in their foraging (Carey et al. 1991) 
Table 25—Partitioning of foraging space by cavity-nesting birds in the Oregon Coast Range, 1–1, based 

on  observations of foraging birds 

Species

Red-breasted 

sapsucker

Hairy 

woodpecker

Pileated 

woodpecker

Chestnutbacked 

chickadee

Red-breasted 

nuthatch Brown creeper

Vertical 

location

-Midcanopy -Midcanopy 

-Understory

-Upper canopy -Midcanopy 

-Lower canopy 

-Understory

-Midcanopy 

-Upper canopy

-Midcanopy

-Lower canopy

-Understory

Horizontal 

location

-Mainstem -Mainstem -Mainstem -Centera

-Outera

-Mainstem

-Centera

Mainstem

Tree 

species

-Douglas-fir

-Bigleaf maple

-Douglas-fir -Douglas-fir -Douglas-fir

-Western 

 hemlock

-Douglas-fir -Douglas-fir

-Western 

 hemlock

Tree 

condition

-Live -Live

-Dead—moderately decayed

-Live

-Dead

-Live -Live -Live

Tree size -Medium

-Large

-Large

-Medium

-Large

-Very large

-Very small

-Small

-Medium

-Large

-Medium

-Medium

-Large

Crown 

class

-Subordinate

-Dominant

-Suppressed

-Dominant

-Subordinate

-Suppressed

-Dominant -Dominant

-Suppressed

-Subordinate

-Dominant -Dominant

-Subordinate

a Branches.

Source: Carey et al. 1991.

C H A P T E R 7 From Ecology to Forest Management 277

Sidenote 53—“At this stage 

of forest ecology, we should be 

able to describe the conditions 

constituting a healthy forest more 

precisely than ‘presettlement’ ... 

science-based approach looking quantitatively at the various 

components, values, and functions 

of ecosystems may be the key to 

describing healthy forest ecosystems” (Tiedemann et al. 2000).

(table 25) and, apparently songbirds as well (Shaw and Flick 1999). 

Massive seed production provides a large foraging environment for 

Douglas’ squirrels (Shaw and Flick 2002) as well as important winter habitat for a variety of resident birds (Haveri and Carey 2000, 

Manuwal and Huff 1987). Individual old-growth trees may support 

2 to 18 kilograms of epiphytes (totaling 132 to 271 kilograms per 

hectare), including alectoroid lichens, cyanolichens, other lichens, 

and bryophytes (Clement and Shaw 1999). Not only do these epiphytes provide nest materials and nest sites for mammals and birds 

(Carey 1996, Carey et al. 1997, Gillesberg and Carey 1991) (table 26), 

but the lichens play important roles in nutrient cycling, especially 

adding nitrogen to the soil during lichen fall, and providing forage 

for squirrels and ungulates. Thus, retention of live trees with heavy 

epiphyte abundances provides a source of propagules in newly reorganizing ecosystems and may have profound effects (Carey et al. 

1991, Peck and McCune 1997). Collectively, the differentiated crowns 

form a rugose canopy that in itself provides added niche dimension, for example, for foraging by bats and olive-sided flycatchers 

(Carey et al. 1991, Wunder and Carey 1996). Thus, differentiation of 
Table 26—Nest materialsa of arboreal rodents that were taken from artificial nest boxes and tree cavities on 

treated (variable-density thinning) and control plots in two forests at Fort Lewis, Washington 

Legacy forestb Thinned forestc

Type of nest materials VDT plots Control plots VDT plots Control plots

Moss species:

Dicranum tauricum

Hylocomium splendens

Hypnum circinale

Isothecium stoloniferum

Kindbergia oregana

Kindbergia praelonga

Plagiothecium undulatum

Rhizomnium glabrescens

0.00

.10

.40

23.20

9.60

0.00

.50

0.00

0.00

.36

.76

40.72

3.36

.08

.40

0.00

.26

.08

1.97

60.03

11.05

0.00

.79

0.00

.40

0.00

7.19

42.29

12.24

0.00

1.31

.05

Total mosses 38.00 45.68 74.18 63.48

Liverwort species:

Frullania nisquallensis

Porella navicularis

Radula complanata

Scapania bolanderi

0.00

0.00

0.00

0.00

.88

.04

0.00

0.00

.08

1.21

0.00

.08

0.00

.43

.02

.02

Total liverworts 0.00 .04 1.28 .48

Lichen species:

Alectoria sarmentosa

Alectoria vancouverensis

Bryoria pseudofuscescens

Cetrelia cetrarioides

Cladonia ochrochlora

Evernia prunastri

Hypogymnia duplicate

Hypogymnia enteromorpha

Hypogymnia imshaugii

Hypogymnia physodes

Hypogymnia tubulosa

Lobaria pulmonaria

Mengazzia terebrata

Platismatia glauca

Ramalina menziesii

Usnea filipendula

Usnea wirthii

23.50

0.00

0.00

0.00

0.00

0.00

.10

0.00

0.00

0.00

0.00

0.00

0.00

.50

0.00

0.00

2.00

5.16

0.00

4.64

.44

0.00

0.00

.04

.24

0.00

.16

0.00

0.00

.04

.28

.16

0.00

7.24

.03

0.00

0.00

0.00

.03

0.00

0.00

0.00

0.00

.18

0.00

.10

0.00

0.00

.03

0.00

1.54

0.00

0.00

.05

0.00

0.00

.02

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

0.00

1.38

Total lichens 26.10 19.28 1.97 1.45

a Mean percentage of nest material. All material that has a mean value of zero occurred in the nests less than 0.01

percent. 

b The legacy forest had been clearcut in ~1937, but many live and dead trees had been left. The forest had regenerated 

naturally into even-aged Douglas fir before our treatments (see Carey et al. 1999d). c The thinned forest had been clearcut in ~1927 and later conventionally thinned twice. Few trees were retained from 

the preceding old-growth forest and dead trees were removed (see Carey et al. 1999d).

Source: Gross 1999.

278 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
C H A P T E R 7 From Ecology to Forest Management 279

branches within crowns and crown-class differentiation among trees 

are interlinked processes fundamental to development of ecosystem 

complexity. The rate at which differentiation proceeds depends on 

degree of intertree competition, legacies (biological legacies and the 

conditions during reorganization, including exogenous disturbances), natural disturbances, and management activities.

Competition—Just as trees jockey for canopy position, various tree 

species may partition the forest floor for fine root concentration—

for example, western hemlock and salal roots become concentrated 

in the upper forest floor, but western redcedar roots may be found 

throughout a soil profile (Bennett et al. 2002). Douglas-fir seems 

to specialize in extending its fine root capacity through symbiosis 

with numerous ectomycorrhizal fungi. That plants build and maintain themselves from energy and materials in the environment and 

must share limited resources is the basis for the self-thinning rule, 

one of the few long-lived quantitative propositions in ecology (Torres et al. 2001). At low light levels (less than 40 percent full sunlight), growth of Douglas-fir is so restricted that little difference 

can be seen among sites markedly different in quality (Drever and 

Lertzman 2001). Western redcedar, however, approaches maximum 

radial and height growth at 30 percent full sunlight. Still, quantification of the relationships between growth in mass, density, basal area, 

and death owing to suppression has proven intractable (Torres et al. 

2001, Zeide 1991), despite considerable economic implications (King 

et al. 2002). 

For Pacific Northwest Douglas-fir, optimum growth occurs at 

initial seedling spacing of 3.7 to 4.6 meters (470 to 740 trees per 

hectare), but many naturally regenerated stands and plantations are 

denser than that (Miller et al. 1993, 2004). Site preparation, burning, and planting Douglas-fir can result in greater dominance by 

Douglas-fir, more rapid attainment of height, and earlier canopy 

closure, leading to competitive exclusion. Natural regeneration after 

site preparation and burning takes place over a longer period, establishes a more even mix of species, may result in slower growth owing to competition with resprouting shrubs, and may keep a diverse 

plant community longer; furthermore, without burning, growth of 

advance regeneration and natural seeding may negate the positive 

effects of planting on wood production (Miller et al. 1993). Even 

in plantations planted to 1,060 Douglas-fir per hectare, more than 

9,900 additional trees per hectare (Douglas-fir, western hemlock, 

and red alder) may become established naturally. Natural regeneration outside of plantations may be as dense as 3,500 to 14,000 trees 
280 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

per hectare. On the eastern Olympic Peninsula, in the area of the 

first (1930) extensive plantings of Douglas-fir in the Pacific Northwest, natural regeneration of western redcedar and western hemlock 

vastly outnumbered that of Douglas-fir following clearcutting in 

1917 through 1919 and wildfire in 1924 through 1925; in the Cascade Range, however, Douglas-fir regenerates well naturally (Miller 

and Anderson 1995). With 9,900 trees per hectare at 9 years, 78

percent of trees may die by 26 years (Miller et al. 1999). But by 

that time, competition among trees will have taken its toll on other 

life forms. Still, the process of competition and differences among 

species in growth rates and shade-tolerance maintains the potential for crown-class and intracrown differentiation, despite the slow 

growth of the surviving trees. Similar results were obtained in the 

first experimental planting of Douglas-fir in 1925 in the southern 

Washington Cascades. Seedlings were planted at 1.2-, 1.5-, 1.8-, 

2.4-, 3.0-, and 3.7-meter spacings (6,723 trees per hectare to 746

trees per hectare). By age 70, the densest plantations had declined to 

less than 2,000 trees per hectare and the least dense retained more 

than 500 trees per hectare. Dense plantings suffered suppression 

mortality, reduced growth, and damage from snow and wind. Such 

stands, if resilient enough to continue to develop through time, may 

undergo crown-class differentiation in addition to heavy mortality 

(Carey et al. 1999b, Miller et al. 2004). The least dense plantations, 

with more than 500 trees per hectare still have sufficient trees to 

sustain the process of crown-class differentiation—and the trees are 

larger and more vigorous than in the dense plantations. Silviculturists commonly focus on the 100 largest trees per hectare—these 

100 trees will form a dominant class that fully occupies the site on 

long rotations (say 80 years or more). Additional variability in tree 

size and subsequent crown condition may be caused by differences 

in soil type, depth, and water-holding capacity that can occur at 

fine scales (1 hectare or less) (Miller et al. 2004). After 70 years, the 

100 largest trees averaged 28 centimeters in d.b.h. and 23 meters in 

height in the dense (1.2- to 1.5-meter spacing) plantations compared 

to 43 centimeters in d.b.h. and 35 meters in height in the plots 

planted to 3.0- and 3.7-meter spacing (Miller et al. 2004). There 

is some evidence for a positive effect of high stand density (up to 

around 3,000 trees per hectare) on early (first 5 years) growth of 

Douglas-fir (Woodruff et al. 2002). Some of this increased aboveground growth could simply be related to competitive strategies in 

Douglas-fir aimed at achievement of dominance; other explanations 

include increased animal browsing in low-density plots, increased 

interspecific competition in low-density plots, a higher probability 
C H A P T E R 7 From Ecology to Forest Management 281

that at least some seedlings find exceptionally good microsites in 

dense plots, and qualitative changes (ratio of red to far-red light) in 

side-light, such as light reflected from adjacent trees, that influences 

the allometry of growing seedlings (the plant parts in which growth 

is concentrated). In any case, the phenomenon is short lived. Without thinning, dense stands eventually suffer high mortality (Wilson 

and Oliver 2000, Woodruff et al. 2002) after drastically reducing 

diversity of the biotic community. 

Silviculturists emphasizing wood production state “Capturing 

the full productive potential of a site requires prompt establishment 

of a uniform stand of trees” (Miller et al. 1993). Of course, they are 

speaking strictly about rate of tree growth (wood production) and 

not joint ecological and economic productivity—or even long-term 

site productivity. Natural regeneration is usually not uniform nor of a 

single species. Thus, in managing for multiple values, a balance must 

be struck with planting to promote development of a new forest 

(versus a shrubland, grassland, or parkland—unless that is a desired 

condition, as in ponderosa pine on dry sites), managing densities of 

trees to promote rapid growth (470 to 740 stems per hectare provide 

for optimum wood production for Douglas-fir), and managing densities, species composition, and spacing of trees to allow for continued 

development of a diverse plant community supportive of animal life 

and resilient to disease, insect attack, and other disturbances. When 

Douglas-fir plantations were thinned experimentally to 740 trees 

per hectare at 9 years, the volume of Douglas-fir at 26 years was 2.5

times that without thinning, with dominants in the thinned stands 

twice as large as those in unthinned stands (Miller and Anderson 

1995). Of course, as trees grow in size, either further reduction in 

density or increased crown-class differentiation is needed for continued rapid growth of dominants. Conventional thinning promotes 

growth but does not necessarily lead to crown-class differentiation 

(Carey et al. 1999d). Conventional thinning produces a stand of big 

trees that may develop deep and differentiated crowns; in time, such 

stands may recruit shade-tolerant trees that add to vertical structure. 

In the short term, conventional thinning may increase susceptibility 

to windthrow (for several years) (Huggard et al. 1999). In any case, 

in densely stocked forests, there seems to be universal potential for 

age-related declines in growth from competition-related changes in 

forest structure and resource-use efficiencies of individual trees that 

can result not only in differentiation but in reduced overall growth 

(Binkley et al. 2002). Thus, to promote development of complex forest ecosystems, some balance of rapid growth and crown-class differentiation must be achieved. This seems possible through legacy 
A

B

282 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 54—(A) A forest that was 

thinned once conventionally shows 

a dense understory with no midstory 

species, whereas (B) a forest that was 

thinned once conventionally and once 

with variable-density thinning 6 years 

earlier shows much more diversity in 

its understory and midstory species. 

Photos by A. Carey.

retention, multispecies management, and variable-density thinning 

(fig. 54).

Competition among trees affects other plants also. Experimental thinning in true fir-hemlock stands in the Pacific Northwest, 

showed not only markedly increased tree growth (5.8 square meters of basal area versus 40.5 square meters 10 years after thinning) 

with reductions in tree density (1,750 trees per hectare versus 250

trees per hectare) but also increased understory productivity, including berry production (Curtis et al. 2000). Tree cover was 66 percent 

in thinned stands and 90 percent in unthinned stands; understory 

cover increased from 58 percent to 72 percent (with an addition of 

four species) in thinned stands and decreased from 58 percent to 

37 percent (with a loss of five species) in unthinned stands as the 

trees grew larger and competition increased. Thus, without thinning, 

trees reduce one another’s growth, exclude other plant life forms, 

and decrease the productivity of the ecosystem, especially for terrestrial herbivores and granivores. An unexpected observation in the 

thinning trials was colonization by epiphytes in both thinned and 

unthinned stands by 10 or more cryptogamic epiphytes. Thinning 

not only increases lights but by causing root gaps also increases the 

availability of water and minerals to understory plants, resulting in 

marked increases in understory abundance and diversity (Thomas 

et al. 1999; Thysell and Carey 2000, 2001a). Fertilization, however, 

can speed canopy closure and lead to reduced understory (Thomas 

et al. 1999).

Although light is often the factor most limiting understory 

development in coastal forests, tree root competition for moisture 

and nutrients becomes important in western interior forests (Riegel 

et al. 1995). Establishment of a new cohort of trees may occur only 
C H A P T E R 7 From Ecology to Forest Management 283

Sidenote 54—How to restore 

ponderosa pine forests (Allen et 

al. 2002):

 Reduce threat of crown fire.

 Prioritize and strategically 

target treatment areas.

 Develop site-specific reference 

conditions.

 Implement multiple conservation initiatives.

 Use existing forest structure as 

a template.

 Restore ecosystem composition.

 Retain trees of significant size 

or age.

 Consider demographic processes.

 Integrate process and structure.

 Control and avoid introducing 

exotics.

 Foster regional heterogeneity 

by using complex topography, 

hydrology, and soils.

 Protect sensitive communities.

 Assess cumulative effects.

 Protect from overgrazing.

 Monitor and conduct research.

 Manage adaptively.

infrequently—40 years might elapse in southwestern ponderosa 

pine forest, and even then, regeneration is often spatially aggregated 

in groups of 3 to 44 trees in patches of 0.02 to 0.29 hectares (White 

1985). This kind of reproduction of ponderosa pine commonly follows the death of one to two large trees in areas intensively burned in 

an otherwise low-intensity fire area. Ponderosa pine reorganization 

does not require much crown-class differentiation in its progression to park-like conditions. At a scale slightly larger than the small 

regeneraton patches, a mosaic may thus be maintained over time 

(Cooper 1960, White 1985). Cooper (1960) described the pattern 

of southwestern ponderosa pine as a result of community development governed by fire and shade intolerance. Shade intolerance 

produces even-aged groups of trees originating in small openings. 

The identity of the group is maintained by fire as the group matures; 

young groups of trees are protected by lack of fuel on the forest 

floor. Litter beneath mature trees provides fuel for fire that prevents 

establishment of young trees. Thus, fire counteracts the tendency of 

trees to take on a random (or in mesic sites, a uniform) distribution. 

Old trees die and groups break up; what took 200 years to develop 

might be gone in less than 20 years; fire then prepares a seedbed, allowing regeneration. There is now a general consensus on an urgent 

need to restore ponderosa pine forests to dynamic mosaics (Allen et 

al. 2002) (sidenote 54). Historically, frequent surface fires, episodic 

regeneration, insect infestations, and drought produced spatially 

heterogeneous patterns at local and landscape scales.

Differentiation in crown class among trees occurs not only as 

a result of intraspecific competition but also interspecific competition, differences among species in growth rates under various conditions, variety in age classes at the time of ecosystem reorganization, 

spatial heterogeneity in the distribution of trees during and after 

reorganization, and heterogeneity in the biotope itself. Crown-class 

differentiation results in growth rates differing among trees and differences in tree diameter, height, crown width, height to live crown, 

crown depth, branch size, and other elements of tree architecture 

(Carey et al. 1991, 1999b; Ishii et al. 2000b; Ishii and Wilson 2001) 

(fig. 55). In forest ecosystem development, organization of foliage in 

three-dimensional space is more important that total amount of foliage (van Pelt and Franklin 2000). For example, Pacific Northwest 

old growth has the highest leaf area index of any forest in the world 

(fig. 56). Even-aged forest with similarly sized trees with foliage in 

one layer will have dramatically different crown architecture and understory light conditions than a tall forest with high foliage-height 

diversity with the same amount of leaf area index. Particularly at 
284 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 55—A complex forest has 

a variety of tree architectures. Graphic 

by A. Wilson; Photos courtesy of 

USDA Forest Service.

high latitudes with low sun angles, the narrow crowns of conifers 

can help promote three-dimensional structure. With differentiation, 

stands may move quickly into understory-reinitiation and nichediversification stages. A significant part of vertical development of 

old-growth Douglas-fir/western hemlock forests is due to the slow 

invasion of the canopy by western hemlock and western redcedar 

(Ishii et al. 2000b). Loss of dominants promotes recruitment of new 

species and stratification, with Douglas-fir dominating at 30 to 50

meters in height, western hemlock at 10 to 45 meters, Pacific silver 

fir at less than 45 meters, Pacific yew below 20 meters, and western 

redcedar throughout the canopy.

Biological legacies and reorganization—Biological legacies can 

facilitate differentiation and inhibit homogeneous intercrown competition through (1) rapid growth of trees established before reorganization and released by destruction of the overstory, (2) continued 

growth of surviving overstory and midstory trees, and (3) spatial 
C H A P T E R 7 From Ecology to Forest Management 285

Figure 56—Multiple layers of 

understory species contribute to the 

Pacific Northwest’s high leaf area 

index. Photo by A. Carey.

heterogeneity of tree regeneration during reorganization owing to 

spatial variation in seed and seedbed availability and owing to falling dead trees (sidenote 55). There is a strong negative nonlinear 

relationship between gap light and the height, d.b.h., density, and 

volume of legacy trees, and aggregation of retained trees provides 

a broad variety of structural elements and environmental conditions, especially photosynthetically active radiation (Drever and 

Lertzman 2003). Legacy retention produced niche-diversification 

stages in fewer than 100 years after ecosystem reorganization in the 

Oregon Coast Ranges (Carey et al. 1999b). Streams also produce 

discontinuities in canopies that promote crown-class differentiation 

and species diversity (Carey 1988, Pabst and Spies 1999). Thus, the 

catastrophic event sets the stage for the ecological play to follow 

(Hutchinson 1965). Even catastrophic disturbances differ locally 

in intensity and produce wide ranges in retention of legacies and 

regeneration of trees. Natural disturbances rarely eliminate all the 

structural elements of the destroyed forest, even in cases of sequential intense disturbances (Franklin et al. 2000, 2002) (table 27). 

Clearcutting for timber production, on the other hand, at the 

height of its development in the mid-20th century, called for elimination of legacies and species not contributing to commercial value 

throughout the life of a stand of trees (Barrett 1962, Smith 1962). 

For example, clearcutting called for cutting all stems more than 5

centimeters in diameter, removal of natural and logging debris by 

mechanical disruption and burning, elimination of vascular plants 

through burning and herbicides, planting a commercially valuable 

tree species, and sometimes fostering growth by fertilization. Stand 

tending during and after reorganization included continuing removal of vegetation competing with commercially valuable crop trees 

(cleaning, weeding, application of herbicides, precommercial thinning, and even pruning to produce uniformity) (fig. 57) and killing 

trees with decadence (defect or decay) during precommercial and 

commercial thinnings or “improvement cuts.” This approach was 

generalized to areas of markedly different climates and disturbance 

regimes, often inappropriately so and sometimes compounded by 

fire exclusion and grazing of livestock (Cooper 1960, Harrod et al. 

1999, Tiedemann et al. 2000). 

Second growth intensively managed for timber (fig. 58) often 

has lost many of the elements needed for development into complex 

forests with high resilience and potential adaptiveness. Indeed, in 

the 1980s, Pacific Northwest foresters began questioning the wisdom of clearcutting followed by burning with its potential for loss 

of nutrients through volatilization and leaching; loss of soil through 
Table 27—Biological legacies differ with type of major disturbance 

in temperate and boreal forests

Legacy Wildfire Windstorm Clearcutting

Large live trees Some Some None

Standing dead trees Many Some None

Fallen trees Many Many Few

Advance regeneration Patchy Much Little

Undisturbed forest 

floor

Patchy Patchy Little

Source: Adapted from Franklin et al. 2002.

286 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 57—Regine Carey stands 

in a recently pruned conifer forest on 

the Olympic Peninsula. Photo by A. 

Carey.

erosion; soil compaction by machinery; loss of genetic diversity in 

trees; lack of natural legacies, such as coarse woody debris, old large 

trees, and deciduous trees; and negative effects on values other than 

timber production (Williamson and Twombly 1983). Decades later, 

similar concerns are still being raised (Harmon and Marks 2002, 

Hennon et al. 2002, Stark and Hart 1999, Thompson et al. 2003, 

Wikstrom and Eriksson 2000). Fear of loss of timber productivity 

after harvest of old growth and site preparation by burning have 

not materialized in controlled studies, but loss of nutrients and soil 

organic matter, soil compaction, stream sedimentation, and effects 

on tree species composition of the new forest are evident—Douglas-fir and hardwoods are favored over other conifers (Heninger et 

al. 2002, Miller and Bigley 1990). Retention of 20 to 30 trees per 

hectare in clearcuts in western Washington ameliorated changes in 
C H A P T E R 7 From Ecology to Forest Management 287

Sidenote 55—Biological 

legacies influence crown-class 

differentiation:

 Advanced regeneration 

responds quickly to overstory 

removal.

 Large live trees provide structure in themselves, sources of 

seed, and eventually disrupt 

the developing canopy by falling.

 Large snags occupy some 

growing space but provide an 

opening enhancing unequal 

distribution of light and water, 

and they eventually fall disrupting the developing canopy.

 Large fallen trees contribute to 

patchiness in regeneration by 

being unsuitable as seedbeds 

to some species but suitable 

seedbeds to other species; 

tall stumps do likewise; both 

may raise regeneration above 

browsing animals.

 Deciduous trees may outcompete conifer regeneration and 

contribute to patchiness as 

well as species diversity.

 Shrubs can contribute to 

patchiness and reduced density 

in tree regeneration.

Figure 58—This recently thinned 

forest lacks in the important elements 

necessary for the development of 

complexity. Photo by A. Carey.

soil and air temperatures but not nutrient loss (Barg and Edmonds 

1999). But green-tree retention can have positive effects on vegetation structure, small mammals, songbirds, woodpeckers, spotted 

owls, Vaux’s swifts, and marbled murrelets (Hunter and Bond 2001, 

Mitchell and Beese 2002, Sullivan and Sullivan 2001, Sullivan et al. 

2001, Titler et al. 2001). Tillage of skid trails helps offset soil compaction by machinery. In Alaska, clearcutting had largely negative 

consequences on wildlife and fish with canopy closure 25 to 35 years 

later nearly eliminating all understory for wildlife for more than 100

years (Hennon et al. 2002). Legacies, including alder, may mitigate 

the impacts of clearcutting.

Substantial controversy reigns over the treatment of forests destroyed by natural catastrophes or seminatural catastrophes (e.g., a 

wildfire arising from anthropogenic ignition may be intensified by 

the ways humans shaped the environment in the past, and contributed to by their shaping the climate of the present). As usual, positions 

among conservationists rapidly become polarized (Lach et al. 2003) 

with Op Ed letters and with emphasis on all-or-none approaches 

(Adams and Ringer 1994, Beschta et al. 1995, Blaine 2004, Fitzgerald 2002, Lindenmayer et al. 2004, Oregon Forest Resources Institute 2002, Sessions et al. 2003, Thomas 2002). Hyperbole abounds. 

Jim Strittholt (Director of the “Conservation Biology Institute”) is 

quoted (Blaine 2004) as proclaiming firmly: “There is no ecological 

justification for post-fire salvage logging in any post-fire environment ... Someone will get rich ... You see a replanted lush green site 

with the eye of a forester, and you see a returning resource ... You 

look with the eye of an ecologist, and you see a plantation, not a wild 

place. If you go in and salvage and plant, that’s not a wild place. That 
288 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

will never be a wild place.” Strittholt’s position accurately identifies 

the nature of the debate. Wildness, wilderness, uncontaminated by 

humans, humans guilty of profaning nature, nature must be protected from humans’ corrupting influence—all are perceptions of the 

urban environmentalist long separated from nature (Dietrich 1992). 

The opposite stance being that of humans immersed in and making 

a living from nature—and making deliberate choices about what to 

destroy, what to exploit, what to intensively cultivate, what to maintain, and what to restore. One view accepts restoration ecology in a 

variety of forms; another would restrict it to passive management 

through reserves. One view would promote biological diversity by 

intentional actions, another would either exploit or reserve. For 

example, the former might plant and shape the slope with coarse 

woody debris to minimize erosion and sedimentation of important 

fish-bearing streams to save a threatened salmon strain; the latter 

may let nature take its course while the strain becomes extinct, and 

patiently wait for however long it takes for the forest to regrow, the 

stream to rehabilitate itself, and another strain of fish to successfully 

colonize the stream. I have heard serious ecologists state words to 

the effect “Sooner or later it will become old growth, even if it takes 

thousands of years” even in the face of reasonably certain climate 

change that might preclude forests of the past from recurring. Thus, 

the debate is not science-based; it is based in worldviews, culture, 

and sources and systems of ways of knowing. It is based on values, 

not ecology—Is it better to let nature take its course or is it better 

to attempt to facilitate system recovery to a humanly desired future 

state? It is in the eye of the beholding person not in the province of 

nature. Is nature a fine-tuned watch with a place for everything and 

everything in its place? Little science supports that idea. Is nature 

totally stochastic and directionless—nature as value-free, no natural catastrophes are possible because they are, after all, natural? Let 

nature take its course—even if nature has no grand plan, no cybernetic guidance system, and no supreme manager guiding the way? 

Given the Gaia hypothesis, the only extraterrestrial input is solar 

energy, everything on the planet is natural, and everything is the 

result of self-organization and natural selection; thus, even the human population explosion precipitating the sixth major extinction 

event in the history of the planet (Thomas et al. 2004) is natural. 

But, nature is and ecosystems are; outside of this earth-bound reality, 

our emotional perceptions and intellectual concepts may or may not 

be accurate assessments of what is. Ecology refers to the relationships between organisms and their environments, not to wildness 

or wilderness or even nature. Wildness, wilderness, and natural are 
C H A P T E R 7 From Ecology to Forest Management 289

in the eye of the beholder except in the extremes. Are Douglas-firs 

germinating from seed collected from the cones of old-growth trees 

but sown from a helicopter no longer natural? What if they were 

one to two generations grown in a nursery? Is the resulting forest 

never to be wild—even if one observes a cougar killing a deer there? 

What about seeing a spotted owl catching a flying squirrel to feed to 

its young? What about being lost, spending the night, and hearing 

the wolves howl?

Active management following catastrophic destruction of a forest can take many forms and produce diverse results. Salvage logging 

can take all to no living trees, all to no large dead trees, or take trees 

from selected patches. Similarly, seeding or planting can be done in 

a variety of ways and produce a variety of results. As in every aspect 

of forest management, the degree of intentionality determines in 

major part the risks of unintended consequences. Postfire salvage 

logging has the potential to markedly alter subsequent bird communities, especially year-round resident species, canopy and cavity 

nesters, and insectivores (McIver and Starr 2001, Morissette et al. 

2002). Salvage removal of large wood affects development of the 

plant community and may reduce species richness while increasing conifer growth in the early years (McIver and Starr 2001). Of 

course the effects of salvage logging differ depending on the percentage of dead and damaged trees removed, how much of each 

tree is removed, the degree to which homogeneity and heterogeneity 

are emphasized, how well retention of legacies (live and dead trees 

and patches of intact forest) is managed, and the other practices 

instituted simultaneously with tree removal, such as felling trees 

perpendicular to slopes to reduce surface runoff and planting appropriate tree species to accelerate forest recovery. Log retrieval systems 

differ considerably in their effect on soils, with ground-based systems having greater negative effects than aerial systems (Adams and 

Ringer 1994, Beschta et al. 1995, Sessions et al. 2003). Ground-based 

logging, however, under certain circumstances can disrupt waterrepellent soil layers developed by severe fires and thereby increase 

infiltration and decrease overland flow. Salvage can mitigate erosion 

with the use of logging residue to impede overland flow, and thus 

contribute to ecosystem recovery. Salvage can also reduce the probability of damaging insect outbreaks (McIver and Starr 2001). Postwildfire seeding, designed to control erosion, may have unintended 

consequences in limiting conifer establishment, promoting exotic 

species, limiting establishment of native herbs and shrubs, and yet 

have no effect on total plant cover; biological legacies and adaptations for dispersal by native plants such as wind dispersal function 
290 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 56—Postfire logging (McIver and Starr 2001):

 The immediate effects of 

salvage will differ with severity 

of burn, slope, soil type, road 

building, and weather.

 Logging systems differ in 

impacts.

 Sometimes logging residue 

decreases erosion.

 The probability of insect population buildups that may infect 

adjacent intact stands can be 

reduced.

 Logging can kill volunteer 

seedlings.

 Broadcast burning can change 

plant succession.

 Patches of disturbed soil 

encourage a variety of plant 

species.

 Skid trails can negatively influence future tree growth.

 Logging can reduce vegetation 

biomass, increase abundance 

of exotic species, and reduce 

native species richness.

 Logging can have negative 

effects on postfire wildlife 

populations.

 Cavity-nesting birds are the 

wildlife most likely to be affected by logging.

 Some wildlife may benefit 

from salvage logging.

well in the absence of seeding with nonnative grasses and legumes 

(Schoennagel and Waller 1999). Thus, management of legacies associated with intense disturbances is complex, and a high degree 

of intentionality is necessary in the analysis of the need for legacy 

management and in formulating a restoration plan for such sites 

(sidenote 56). Answers to questions about salvage and restoration 

after natural or anthropogenic catastrophes are not simple all-ornone answers if conservation is aimed at achieving the diverse values 

that society needs and wants from forests. The answers can be simple only if the goal is simple—let nature proceed unhindered and 

unaided (no matter what the short- or long-term consequences are) 

versus recover economic value before it is lost (no matter what the 

short- or long-term consequences are). It seems obvious, however, 

that care must be exercised and substantial legacies must be retained 

if rapid ecosystem recovery is to be obtained (Franklin et al. 2000, 

Sessions et al. 2003).

Second-growth forests differ markedly in character depending on how and when they were established and how they were 

subsequently treated. Simple near-monocultures of Douglas-fir or 

western hemlock and Douglas-fir/red alder stands are common in 

the Pacific Northwest. In areas logged from railroad systems during 

World War II on the Olympic Peninsula, however, some complex 

second-growth forests have developed under the influence of heavy 

loads of legacy coarse woody debris; in southwestern Oregon, selective or partial harvests left many legacies that allowed reorganization to produce complex second-growth forests. In the Sierra Nevada of California, railroad logging so efficiently removed all trees 

that scientists had trouble reconstructing fire histories (Stephens 

and Collins 2004).

Ecosystem reorganization after natural catastrophic destruction 

of the tree canopy and reestablishment of a tree canopy may take a 

long time (more than 50 years, Huff 1995) with substantial coarse 

woody debris left on site as standing dead trees, decayed fallen trees, 

and recently fallen dead trees (Spies and Franklin 1991). Numerous live trees and multiple species of trees may be left, germinate, 

or invade after disturbance, and understory vegetation may persist 

or quickly recoup. Over large areas, heterogeneity produced by biological legacies, variation in natural regeneration, and intermediate 

disturbances during a long reorganization stage may result in rapid 

crown-class differentiation with the competitive-exclusion stage 

being rare in the landscape and rapid growth of Douglas-fir and 

other trees (Poage and Tappeiner 2002, Tappeiner et al. 1997). In 

western Oregon, low tree densities are promoted by (1) lack of seed 
C H A P T E R 7 From Ecology to Forest Management 291

Sidenote 57—Promoting 

crown-class differentiation:

 Legacy retention—live trees, 

standing dead trees, fallen 

trees, and seed banks

 Promoting multiple tree species during reorganization 

during planting, weeding, and 

precommercial thinning

 Variable-density thinning

 Underplanting

 Multiple entries for tree 

removal

 Individual tree release

 Tree limbing or topping to 

foster development of reiterated trunks or complex crowns

sources following disturbance, (2) sporadic seed production, (3) seed 

predation, (4) inadequate safe sites for seedling establishment, (5) 

climatically unfavorable periods, (6) early competition by herbs and 

shrubs, and (7) herbivory. On a small site in Washington following catastrophic fire, regeneration was also prolonged—40 years or 

more—but eventually a high density of trees was attained, followed 

by significant natural thinning of the original cohort of Douglasfir (Winter et al. 2002a). Surviving Douglas-fir developed deep 

crowns. Although some western hemlock may have been present 

from origin, at least three disturbances (at 90, 250, and 430 years) 

promoted subsequent major recruitment and growth episodes for 

western hemlock with many secondary pulses of growth in between 

(Winter et al. 2002b). The presence of even-aged cohorts in patches 

is compelling evidence of disturbance (Duncan and Stewart 1991). 

Similarly, in an Engelmann spruce-subalpine fir-lodgepole pine forest in southern interior British Columbia, pine became established 

in the first 5 years, spruce increased over the first 50 years, but few fir 

became established in the first 50 years after catastrophic fire (Antos 

and Parish 2002). Spruce present in the canopy in the old-growth 

stages had differentiated in response to a combination of partial disturbances and endogenous autogenic processes. Releases occurred 

in most decades but were concentrated around 110 years and 300

years after origination; these may have been related to spruce budworm outbreaks that produced canopy thinning. Patchy budworm 

outbreaks led to patchy establishment of fir. Furthermore, different 

age categories of trees showed different patterns of aggregation. The 

oldest trees showed no overall deviation from a random pattern, trees 

originating at 100 years showed patterns that differed among plots, 

and trees that originated at 300 years were clumped at distances up 

to 20 meters. Thus, the process of crown-class differentiation and 

the development of crown-class differentiation in the trees collectively may recur throughout the duration of structurally and compositionally diverse forests (sidenote 57). Antos and Parish (2002) 

suggested that most old, fire-initiated forests are similarly structured 

by a combination of exogenous partial disturbance and autogenic 

processes and that management should incorporate similar dynamics. There was no evidence of exogenous disturbance in the first 

200 years. Then episodes of disturbance were reflected by periods of 

release in the understory; after disturbance, firs were able to attain 

positions in the canopy. In boreal forests, regeneration following fire, 

spruce budworm infestation, windthrow, or timber harvests depends 

on numerous biotic parameters: (1) production of seeds and asexual 

regeneration of stems as a function of surviving tree densities; (2) 
292 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

dispersal of seed by wind; (3) germination of dormant seeds in the 

soil; (4) organic layer depth after disturbance as it affects germinant mortality; and (5) advance regeneration of shade-tolerant trees 

(Greene et al. 1999). In dry areas characterized by competition for 

moisture and by frequent return intervals for fires of light to moderate severity, crown-class differentiation may not be an important 

process—savannahs and widely spaced groves of trees may form in 

response to poor, infrequent, or short-lived regeneration (Cooper 

1960). But, regeneration occurs in patches, and crown-class differentiation is apparent among patches, and eventually within patches 

early in the development of those patches.

Timber management—Timber management shortens reorganization and quickly moves the stand into competitive exclusion or 

biomass accumulation. With limited legacies and a dense cohort of 

naturally or artificially established trees, the diversity of plant species and many other life forms decreases with canopy closure. The 

resulting competitive exclusion and biomass accumulation concentrated in trees may last over 70 years (Carey et al. 1996a, 1999b; 

Long 1977) and recovery of plant species diversity may be slow even 

at 75 years (Long 1977); peak in diversity may be delayed until old 

growth (Halpern and Spies 1995). Similarly, small mammal abundance and diversity are reduced as the canopy closes and understory 

decreases and may remain low for decades (Carey and Harrington 

2001, Hooven 1969, Wilson and Carey 2000). In plantations, evenly spaced seedlings may fail to differentiate, are susceptible to diameter-growth stagnation, and may become unstable (Wilson and 

Oliver 2000). Stagnation can increase susceptibility to windthrow if 

thinning occurs later. Natural thinning of young Douglas-firs produces small, ephemeral gaps as individual trees die. These small gaps 

do not contribute much to crown-class differentiation or to recovery of plant species diversity (Spies and Franklin 1989). Nevertheless, small gaps, the relatively thin crowns of Douglas-fir, and random variation in spacing often allow reinitiation of an understory of 

salal or sword-fern. The density, basal area, foliar productivity, biomass, and cover of salal is related almost exclusively to light, increasing with increasing transmission of light through the tree canopy 

(Vales 1986). This course of development is typical of forests reorganizing after clearcutting and burning (Carey et al. 1996b, Halpern 

and Spies 1995, Long 1977, Long and Turner 1975). Intermediate 

disturbances such as root-rot infestations often produce pockets of 

understory reinitiation in second-growth stands (Carey et al. 1996b, 

Holah et al. 1993). In mesic areas where shade-tolerant species are 
C H A P T E R 7 From Ecology to Forest Management 293

abundant, even denser canopies may form, facilitated by legacies of 

well-decayed nurse trees. These competitive-exclusion stands may 

last longer and produce an intense ecological “crunch” on biodiversity as trees strive to compete for a height advantage and exclude 

smaller life forms (Carey 1995, 1996; Carey and Johnson 1995; Carey et al. 1996b; Stewart 1986, 1988). Overstory cover explains more 

than 50 percent of the variance in shrub cover, including vine maple 

cover; even stronger relationships exist with maximum total shrub 

cover, total herbaceous cover, and the cover of each of the three functional groups of herbs (Carey et al. 1999b, McKenzie et al. 2000a). 

Thus, severe disturbance followed by dense regeneration results in a 

stage of development that inhibits biodiversity. 

Land use change, grazing, timber management, and fire exclusion have produced dense, relatively homogeneous, mixed-species 

ponderosa pine forests at risk to catastrophic destruction in areas 

previously characterized as ponderosa pine woodlands (Wright and 

Agee 2004 and many others). Not only are present forests more 

homogeneous, but often large trees have been removed, small trees 

occur in thickets, community composition has shifted to less fireresistant species, understory grasses and forbs have decreased in 

abundance and have been replaced by deep mats of slowly decomposing needles that disrupt nutrient cycling, decrease biological diversity, and disrupt hydrologic cycles. Old-growth ponderosa pine 

forest is rare and what were meadows associated with these oldgrowth forests are now forests.

Competitive exclusion stages—If crown-class differentiation is 

delayed, the ecosystem may enter the competitive exclusion stage 

of development, wherein the system actually becomes more simplified over time instead of increasing in complexity. Salient features 

of competitive exclusion are even-aged, dense trees and suppression 

mortality. Hardwoods, notably red alder, giant chinquapin, Pacific madrone, and bigleaf maple, occasionally produce heterogeneity 

in competitive-exclusion stands that allows some crown-class differentiation. Shade-tolerant conifers may be rare in the understory 

during competitive exclusion, especially on dry to mesic sites. Second-growth competitive-exclusion stands 40 to 70 years old averaged 384 live conifers per hectare and 123 snags per hectare in the 

Oregon Coast Range (Carey et al. 1999b), about 50 percent more 

than the 85 snags per hectare reported by Carey et al. (1991) for a 

mixture of natural and managed competitive-exclusion stands there, 

but similar to second-growth competitive exclusion on the Olympic 

Peninsula (121 snags per hectare) (Carey 1995). In the Puget Trough 
294 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

of Washington, 60-year-old competitive exclusion averaged 500

Douglas-fir per hectare (34 snags per hectare). For Douglas-fir of 

this age and size (quadratic mean diameters of 30 to 40 centimeters), excessive restriction of crown development (and concomitant 

mortality owing to suppression) occurs at densities of 350 to 540

trees per hectare (Curtis 1982, McArdle et al. 1961). In eastern deciduous forests, 490 trees per hectare would be common (Bormann 

and Likens 1979). In western interior Northwest forests, trees are 

often smaller and their densities substantially higher. In Wyoming, 

subalpine spruce-fir forests, both species grow slowly as seedlings 

and saplings and live suppressed for many years until released by 

some disturbance (Oosting and Reed 1952). For example, 337-yearold subalpine forest canopies in interior British Columbia may have 

450 stems per hectare (with nearly 800 more stems per hectare subcanopy), even after an 80-year period of reorganization followed by 

200 years of growing without disturbance followed by major mortality owing to bark beetles (which released suppressed trees also), 

then another, but shorter, bark beetle outbreak 30 years later, and 

a small outbreak 60 years after that (Parish et al. 1999). The diversity of effects that disturbance can have on forest dynamics is well 

recognized. Large fires can produce extensive homogeneous stands 

of trees, whereas insects, disease, and blowdown create patchiness 

and fine-scale heterogeneity (Parish et al. 1999). Natural variation 

in stocking, advance regeneration, and occasional retention of large 

trees from previous stands may contribute to crown-class differentiation in otherwise dense second growth. 

Discussion—A salient feature of Pacific Northwest niche-diversification and old-growth stands is large Douglas-fir with deep crowns 

and large, platform branches, epicormic branches, and reiterated 

trunks (Carey et al. 1991, Franklin et al. 1981, Spies and Franklin 

1991), architecture unlikely to develop in competitive-exclusion and 

biomass-accumulation stages. Old stands also have shade-tolerant 

conifers including grand fir, western hemlock, western redcedar, 

and incense cedar and sometimes bigleaf maple or Pacific madrone. 

Presumably, crown-class differentiation in niche diversification and 

old growth was not only a result of the stage-setting catastrophe 

that destroyed the previous stand, but also one of multiple species, 

competition, disease, injury, and mortality of the aging cohort of 

trees that produced gaps followed by establishment and growth of 

shade-tolerant conifers. Density-dependent processes (e.g., intertree competition and disease outbreaks such as root rot) are more 

likely in younger forests and density-independent processes (e.g., 
C H A P T E R 7 From Ecology to Forest Management 295

Figure 59—This conventionally 

thinned forest has a dense understory, 

no midstory, and an overstory of trees 

in intense competition with each 

other. Photo by A. Carey.

gap formation owing to individual large trees falling because of butt 

decay by velvet-top fungus) are more likely to occur in older forests. 

Crown-class differentiation accounts for more variance in stand 

structure than any other factor. Diameter at breast height alone can 

separate age classes in broad-scale surveys (Carey et al. 1991), and 

most variance among age classes across the Pacific Northwest can be 

reduced to a single canonical variate related to the standard deviation of d.b.h. and the density of large trees (Spies and Franklin 1991). 

But, large-diameter trees can also be grown in plantations, and, in 

these simplified ecosystems, d.b.h. no longer serves as a good predictor of stage of ecosystem development; such trees may have quite 

homogeneous, simply structured crowns (fig. 59). In old forests, as 

trees became dominant they not only increased in d.b.h., but also in 

height, crown depth (and often width), limb size, variation in limb 

size, occurrence of epicormic branching and reiterated branches and 

trunks, bark rugosity, and root networks (fig. 60). These architectural 

changes magnified individual tree dimensions, and multidimensionally increased niche space for other animals and plants. Enhanced 

characteristics included (1) greater, more consistent production of 

seed for seed-eating birds and mammals (Buchanan et al. 1990, 

Carey 1991, Manuwal and Huff 1987); (2) increased surface area for 

mycorrhizae, epiphytic plants, and endophytic parasites—up to 97

species of lichen can occur in a small stand with well-differentiated 

crowns (Enseen et al. 1996, McCune et al. 2000, Parks and Shaw 

1996, Sillet and Neitlich 1996, Stone et al. 1996); (3) bark crevices, 

foliage, and arboreal soil for invertebrates (Denison 1973, Mariani 

1987, Schowalter 1989); (4) crevices for bat roosts and materials and 

platforms for nests of mammals and birds (Carey 1996, Carey et al. 

1997, Forsman et al. 1984, Gillesberg and Carey 1991, Hamer and 

Nelson 1995, Wunder and Carey 1996); and (5) an increased variety of foraging substrates and prey (and niche separation) for barkgleaning and wood-pecking birds (Carey et al. 1991, Sharpe 1996). 

At the stand level, crown-class differentiation results in a rugose 

canopy that provides unique foraging spaces for bats (Wunder and 

Carey 1996) and birds (e.g., the olive-sided flycatcher) (Carey et al. 

1991). 

Crown-class differentiation accounted for 25 percent of variance in vegetation structure in a mixed sample of young and old 

stands in Oregon and provided a major dimension of the realized 

habitat of Townsend’s chipmunks (Carey et al. 1999b). Mean tree 

d.b.h. also was a good predictor of the abundance of Townsend’s 

chipmunks on the Olympic Peninsula, explaining 61 percent of the 
296 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 60—An old-growth forest 

on the Olympic Peninsula shows 

complexity in tree architecture. Photo 

by T. Wilson.

variance (Carey 1995). Two alternative explanations of the strong 

correlations of abundance of chipmunks with crown-class differentiation appear reasonable: (1) crown-class differentiation was a surrogate for the entire process of forest development or (2) chipmunks 

were responding to heavy seed production by large, dominant trees. 

Conifer seed is a major dietary component for Townsend’s chipmunks, which harvest and store the seed for the winter (Sutton 

1993). Townsend’s chipmunks seem to be food limited, and their 

abundance can be increased by adding seed (Sullivan et al. 1983). 

The same seems true for the third squirrel in Pacific Northwest forests—the Douglas’ squirrel, whose behavioral repertoire is geared at 

safekeeping sources and stores of conifer seed (Smith 1970). Chipmunks have a strategy of capitalizing on seasonally available seeds, 

fruits, and fungal fruiting bodies, storing food for winter, and facultatively hibernating to reduce energy needs during winter. Crownclass differentiation is a minor dimension of flying squirrel realized 

habitat; flying squirrels specialize on truffles, mushrooms, and fruits 

and seeds of shrubs and deciduous trees.
C H A P T E R 7 From Ecology to Forest Management 297

Crown-class differentiation is perhaps the factor of forest development most amenable to management: (1) species composition can 

be determined managerially at initiation of a new stand by legacy 

retention, planting, allowing natural regeneration, and maintaining and promoting diversity during precommercial thinning; (2) 

management of stem density and growth rates is well founded, and 

quantitative measures exist for the degree of intercrown competition in trees (Curtis and Carey 1996); and (3) spacing can be varied 

tree to tree or patch to patch within stands to promote both crownclass differentiation and crown development (Carey 1995, Carey et 

al. 1996a, 1996b). Growth of large trees and the passage of time lead 

to disease, injury, decay, and death of trees and consequent expansion of multidimensional niche space. Thus, the ecological influence 

of crown-class differentiation extends beyond tree architecture to 

interaction with decay processes to produce decadent structures of 

large biomass. Decay processes seem less deterministic than differentiation; yet, management easily can have marked impacts on 

decadence.

Decadence

The Oxford English Dictionary (OED) defines decadence as “The 

process of falling away or declining (from a prior state of excellence, 

vitality, prosperity, etc.); decay; impaired or deteriorated condition.” 

Decadence has long been recognized as playing important ecological roles in forests, not only for soil organisms and plants, but for 

animal communities as well (Elton 1966, Hamilton and Cook 1940). 

In forests, decadence refers to both state of the forest (degree of 

decadence) and to processes by which trees (1) become infected with 

rots, often as a result of physical damage, insect attack, or disease; 

(2) balance decadence with renewal—broken tops with reiterated 

trunks and large dead and broken branches with epicormic branches; (3) develop decayed heart wood, cavities in their tops, and hollow 

boles; (4) uproot or break and fall to gradually decay to become incorporated into soil; and (5) die while standing and gradually decay 

to fall or break up into smaller pieces (fig. 61) (table 28). 

Contrary to the OED definition, a modicum of decadence in 

forests contributes to “vitality and prosperity” and renewal. Of particular importance to forest conservation is maintaining long-term 

site productivity. For example, coarse woody debris can be important in cation cycling in base-poor systems, in maintaining surface 

organic layers in areas where decay is rapid or fires are frequent, in 
Table 28—Density of standing dead trees (snags) by diameter class 

and age class in young, mature, and old forests in the Oregon Coast 

Rangea

Snag size (d.b.h. in cm) Young Mature Old

>100 0.1 0.3 3.3

>50 0.8 4.3 7.3

20–49 17.6 55.6 8.4

10–19 64.9 39.0 7.0

a This illustrates the transition from density-dependent mortality to 

density-independent mortality and from smaller trees to larger trees 

with increasing forest development. In Washington, snags larger than  

centimeters d.b.h. were more abundant in old growth—averaging  per 

hectare—than in second growth—only 1 to 1 per hectare.

Source: Carey et al. 11.

298 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 61—Decadence in a 

second-growth forest in the Puget 

Trough: a recently snapped tree bole 

and an adjacent uprooted tree. Photo 

by A. Carey.

retaining moisture during dry periods and preventing erosion during wet periods, for seedling establishment in coastal Pacific Northwest forests, and as habitat for a variety of organisms (plants, fungi, 

and animals) in most forests (Laiho and Prescott 1999). In relation 

to sustaining site productivity and timber harvesting, the question 

is whether the total nutrient pool left on site in biological legacies 

(rather than simply coarse woody debris) and the rate of nutrient input through weathering and precipitation are large enough to offset 

loss of nutrients in harvested timber. Management of faster cycling 

materials, such as ground vegetation and nonwoody litter, may be 

as or more important than coarse woody debris. For example, on 

Rocky Mountain conifer forests in Alberta, Canada, coarse woody 

debris did not appear to make significant contributions to nitrogen 

and phosphorous cycling; the organisms producing woody decay 

may have actually competed with plants for the limiting nutrients 

that became available. Litter and coarse woody debris, however, do 

provide refugia during fires for a variety of beneficial fungi, microbes, and inverterbrates that are important to nutrient cycling and 

decomposition in western interior forests (Niwa et al. 2001) and are 

thus important to forest resilience. Coarse woody debris is a major 

component of Rocky Mountain forests and is important to forest 

soils (Graham et al. 1994). The dynamics of coarse woody debris differ with forest type, seral stage, insect and disease activity, weather 

events, fire-return intervals, and management activities. The wood 

lasts 60 to 500 years depending on the ecosystem type, longer in 

mesic systems and shorter in xeric systems. Amounts range from 

66 Mg/ha in cedar-hemlock forests to 23 Mg/ha in ponderosa pine 
C H A P T E R 7 From Ecology to Forest Management 299

Figure 62—A fallen ponderosa 

pine near Sisters, Oregon. Photo by A. 

Carey.

Sidenote 58—The role of 

coarse woody debris in Rocky 

Mountain forests (Graham et al. 

1994):

 Protects the forest floor and 

mineral soil from erosion and 

mechanical disturbance

 Protects new seedlings from 

livestock grazing

 Key habitat element for many 

species of wildlife

 Important in stream ecology

 Interrupts airflow, provides 

shade, insulates and protects 

new forest growth

 In mesic forests, provides 

seedbeds and nursery area for 

conifer seedlings

 With advanced decay, holds 

large amounts of water providing moisture for vegetation 

during dry periods

 Stores nutrients (sulphur, 

phosphorous, nitrogen) that 

are released through decay or 

burning

 Provides humus for ectomycorrhizal root tips

forest (fig. 62). The abundance of ectomycorrhizal root tips is a good 

indicator of the health of Rocky Mountain forest soils and exhibits 

a strong positive relationship with soil organic matter, which is positively related to coarse woody debris inputs. Empirical data suggest 

that optimum soil organic matter can be maintained by 10 to 20

Mg/ha of coarse woody debris, depending on forest type (sidenote 

58). Historically, wildfires left 100 to 600 Mg/ha, depending on forest type. Maintaining well-distributed 15 to 30 Mg/ha on dry sites 

and 30 to 50 Mg/ha on mesic sites by minimizing roller chopping, 

chipping, and smashing slash while using prescribed fire to remove 

needles and branches (hazard fuels) can maintain the ecological 

roles of coarse woody debris. 

In the Pacific Northwest, there has long been an interest in the 

role of coarse woody debris in nutrient cycling and long-term site 

productivity; however, our understanding is still limited (Edmonds 

and Chappell 1994; Edmonds et al. 2000; Edmonds and Murray 

2002; Marra and Edmonds 1994, 1996; Sollins 1982; Sollins et al. 

1980). In Douglas-fir/western hemlock/western redcedar forests, 

decay of coarse woody debris over the long term does result in net 

nitrogen mineralization (Hart 1999). Catastrophic inputs of coarse 

woody debris assist forest recovery by timing of nutrient release that 
300 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 63—Coarse woody debris, 

both standing and fallen, provides 

shelter and places to forage for wildlife. Photo courtesy of USDA Forest 

Service.

matches nutrient demands and helping to prevent erosion. In many 

old-growth forests, more than 20 percent of the area of the forest 

floor is covered by coarse woody debris (fig. 63) with well-decayed 

boles covering more than 5 percent of the forest floor. This material can contribute to rapid recovery of the system after disturbance. 

Tree retained after catastrophic disturbance (natural on managed) 

often show signs of old age and decadence: fungal infections, large 

cracks, densely furrowed bark, broken tops, multiple leaders, cavities 

and basal hollows, large-diameter limbs defective in form, numerous 

epiphytes, and deep crowns suggestive of an open-grown growth 

form (Hunter and Bond 2001). Catastrophic fires, insect outbreaks, 

and epidemics of disease often leave large numbers of snags used by 

woodpeckers and other cavity-using birds (Imbeau and Desrochers 

2002, Johnson and O’Neil 2001, Lundquist and Mariani 1991, Rose 

et al. 2001). Snags used by cavity excavators may differ markedly in 

abundance from 453 per square kilometer in Oregon to 233 per 

square kilometer in British Columbia to 1.3 per square kilometer in 

the Cariboo Parklands of Alberta (Bonar 2000, Johnson and O’Neil 

2001). Reviews of snag abundance and use by wildlife have been 
C H A P T E R 7 From Ecology to Forest Management 301

Figure 64—Western redcedar 

trees can compartmentalize decay 

and remain alive, even with such large 

cavities. Photo by A. Wilson.

compiled for practically all regions of North America 

in wildlife-habitat relationships books; Johnson and 

O’Neil (2001) provided a recent review for Washington and Oregon. The importance to wildlife of 

standing dead trees, live trees with moderate to heavy 

decay (fig. 64), and fallen trees cannot be overstated 

(Bunnell et al. 1999), and substantial effort has gone 

into modeling the dynamics of coarse woody debris, including models that produce advisory output 

for managers (Mellen and Ager 2002; Mellen et al. 

2002, 2004; Wilhere 2003). Conventional timber 

management in Washington includes (1) clearcutting 

with retention of 7 to 12 wildlife trees per hectare followed by planting 1,075 Douglas-fir per hectare; (2) 

precommercial thinning at 15 years of the plantation 

to 741 trees per hectare; (3) commercial thinning at 

30 years (if done) to 346 trees per hectare; and (4) 

clearcutting at 50 years (Wilhere 2003). Such management results in snag densities of about 20 percent 

of the total snags and 1 percent of the large snags in 

natural forests. Average predicted densities were 3.9

small snags per hectare, 6.2 medium snags per hectare, and 0.1 large (more than 64-centimeter d.b.h.) snags per hectare. 

In conifers, it is the moderately decayed large snags and very large 

(more 80-centimeter d.b.h.) snags that provide most of the cavities used by birds. Similarly, the importance of forest decadence to 

aquatic systems is profound (Acker et al. 2003).

Live trees with extensive decay, standing dead trees, and fallen 

trees are used by a tremendous diversity of plants, fungi, microorganisms, invertebrates, and vertebrates (Boddy 2001, Harmon et al. 

1986, Jonsson and Kruys 2001, Kruys and Jonsson 1999, Kuuluvainen et al. 2001, Maser and Maser 1988, Maser and Trappe 1984, McComb and Lindenmayer 1999, Siitonen 2001). Coarse woody debris 

is characteristic of natural forests from the spruce taiga in the Ural 

Mountains of Russia (36 fallen trees more than 10 centimeters in 

d.b.h. along 10 meters of transect) to the Pacific Northwestern United States, where up to 27 percent of the forest floor may be covered 

with coarse woody debris (Marra and Edmonds 1994). In Scandinavian forests, 4,000 to 5,000 species (20 to 25 percent of all species) 

are associated with coarse woody debris, which averages 60 to 90

cubic meters per hectare in old growth but only 2 to 10 cubic meters 

per hectare in managed forests (fig. 65). Furthermore, the process 

of decadence is important in the development of spatial complexity 
302 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 65—Coarse woody debris 

in a managed forest in Sweden. Photo 

by A. Carey.

in the forest and in the soil. Trees dying lose their foliage and allow 

light to penetrate the canopy more fully. Falling trees may damage 

other trees and create larger canopy gaps. Fallen trees provide structure to the forest floor and seed beds for a variety of plant species; 

eventually they become incorporated into the soil and fully infiltrated by roots; various organisms, especially beetles, convert fallen trees 

into humus and fine organic matter in the soil. Large dead wood 

(standing dead trees, fallen trees, and large tree parts) resulting from 

decadence is often referred to as coarse woody debris. 

Abundance of coarse woody debris accounted for 16 percent 

of the total variance in vegetation structure in managed and natural forests in southwestern Oregon (Carey et al. 1999b). Cover of 

fallen trees in the Oregon Coast Ranges averaged 10 percent in old 

growth, 7 percent in niche diversification forest, and 4 percent in 

competitive exclusion forests. In Washington, cover of fallen trees 

averaged 13 percent in old growth but ranged from 2 to 13 percent, 

averaging 8 percent in second growth (Carey and Harrington 2001). 
C H A P T E R 7 From Ecology to Forest Management 303

Sites used by flying squirrels averaged a 10 percent cover of fallen 

trees in both regions. The types and abundance of coarse woody debris resulted from three separate phenomena: (1) retention of live, 

damaged, and dead trees through and after the catastrophe that 

initiated the reorganization of the ecosystem; (2) death of young 

trees through suppression, disease, weather damage, fire, and falling large trees; and (3) development of decadence in live trees over 

time. Intermediate and small-scale disturbances including wildfires 

( Juday 1977), diseases such as root rot (Carey et al. 1996b, Holah et 

al. 1993) and white pine blister rust (Lundquist and Mariani 1991), 

windstorms (Carey and Johnson 1995), snowstorms, and ice storms 

(Carey et al. 1997) promote decadence. These disturbances, however, 

are stochastic and differ in frequency and intensity from place to 

place and time to time, producing high variance in decadence within 

age classes of forest that may differ markedly in other elements of 

structure as well. 

Historical clearcutting left substantially less coarse woody debris than did natural catastrophes, removed most or all live trees, 

and was followed by fast, dense, and monospecific regeneration of 

trees that quickly moved the stand into the competitive-exclusion 

stage. Early (about 1910) logging of old growth left 52 to 56 percent 

of preharvest biomass, contemporary logging of old-growth leaves 

33 to 41 percent, and contemporary harvest of second-growth leaves 

only 31 to 35 percent—a reduction from 500 to 540 megagrams per 

hectare to 100 to 115 megagrams per hectare (Harmon et al. 1996). 

The trend has been for intensive management for timber to result 

in marked loss of biodiversity owing to reductions in coarse woody 

debris and increases in homogeneity and simplicity of the resulting forest. Management can deconstruct ecological processes and 

shape them to narrow ends. Maintenance of homogeneity through 

maintaining evenly spaced trees can promote biomass accumulation 

without crown-class differentiation, forestall or prevent suppression 

mortality, and remove trees with incipient decadence. Decoupling 

of basic processes has profound influences on ecological complexity, diversity, and resilience. Even in natural forests, processes can be 

decoupled. After especially severe catastrophes, coarse woody debris 

declines in abundance until old growth is reached at about 190 to 

250 years (Spies and Franklin 1991). But when trees are killed or 

weakened by fire, coarse woody debris recruitment may continue 

for over 100 years (as in contemporary niche-diversification stands) 

until death of older trees begins to maintain recruitment of coarse 

woody debris (Franklin et al. 1987). Managed stands are harvested 

during competitive exclusion, or if precommercially or commercially 
304 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 59—Considerations for managing cavity trees 

(Bunnell et al. 1999):

 Manage a continuum from live 

trees to standing dead trees to 

fallen trees to trees incorporated in the soil.

 Twenty to thirty percent of 

the vertebrate fauna [of British 

Columbia] use cavities—57

species in interior Douglasfir forest; the proportion of 

species using cavities increases 

with mean fire size and frequency of fire.

 Decay states differ between 

deciduous trees (sound sapwood, heart rot) and conifers 

(moderately decayed sapwood 

and heartwood).

 Birds and mammals commonly prefer hardwoods over 

conifers, even small d.b.h. 

hardwoods, but 66 percent of 

weak excavators use only dead 

trees, and some of these are 

the most threatened by lack of 

decandence management.

 A number of species (e.g., 

Vaux’s swift, black bears, 

American marten) use hollow 

trees that require heart rot and 

a long time of decay.

 Size matters—densities of 

cavity users is correlated with 

densities of large snags but not 

small snags, and cavity users 

respond the most to increases 

in snag densities primarily at 

low snag densities; conifers 

more than 80 centimeters and 

deciduous trees more than 40

centimeters with height more 

than 20 meters are sought out; 

2.4 large snags per hectare 

supports 50 percent of the 

maximum density; increase 

in number of cavity nesters 

reaches a maximum [levels 

out] at about 5 large snags per 

thinned, during biomass accumulation, generally at 40 to 70 years 

old, with high utilization of wood and rapid regeneration through 

planting (Carey et al. 1999c). With intensive management for timber, 

recovery of biodiversity by the ecosystem may be restricted severely 

because of reduced crown-class differentiation and decadence.

Decay in live trees—The entry of decay-causing organisms, the 

development of decay, and the timing of tree death varies markedly with species (Browne 1956, Eslyn and Highley 1976). Decay 

in live trees that enables cavity excavation by woodpeckers, allows 

cavities to develop for squirrels and other mammals, and leads to 

hollow trees is more common in deciduous trees than in conifers 

(sidenote 59). The processes leading to decay in deciduous trees are 

well understood (Carey 1981, Hansen 1966, Manion and Zabel 1979, 

Shigo 1979, Wagener and Davidson 1954, Wilkes 1982) as are factors underlying the distribution of live cavity trees (Carey 1983). 

For example, in relatively even-aged oak-hickory forests in West 

Virginia, the spatial pattern of the occurrence of the various species 

of oak, hickories, and other trees was roughly determined by slope 

position, aspect, and other variable site qualities in a small landscape 

(Carey 1983). But the species differed markedly in their propensity 

for forming discrete cavities useful to wildlife, for becoming hollow 

trees, and for longevity. White oaks, especially chestnut oak, were, 

perhaps, the best cavity providers, with northern red oak and scarlet 

oaks not as prolific. Older forests, dominated by northern hardwoods 

had even fewer cavities. In southwestern Oregon old-growth forests, 

large, old, dead, moderately decayed Douglas-fir provided the majority of cavities for birds (Carey et al. 1991). But on the Olympic 

Peninsula, large, live western redcedar with heart rots were important to pileated woodpeckers (Aubry and Raley 2002). In the western Washington Cascades, large, old, white pines that died from 

blister rust provided the greatest number of cavities (Lundquist and 

Mariani 1991). Grand fir is not as long-lived as Douglas-fir, but it is 

a good cavity tree and is somewhat unique among the firs in regularly becoming a hollow tree, that, when it falls, provides den sites 

for American marten and other mammals. Deciduous trees, such 

as red alder, willow, Pacific madrone, and bigleaf maple are apt to 

have cavities earlier in the life of a forest than Douglas-fir. Similarly, species differ in their susceptibilities to different diseases and 

in the timing when mortality might occur and contribute to coarse 

woody debris on the forest floor. Studies of second-growth forest 

in the Puget Trough of Washington, surprisingly, found increasing 

recruitment of large tree boles to the forest floor in stands more than 
C H A P T E R 7 From Ecology to Forest Management 305

hectare in the Pacific Northwest.

 Preferences for snags for 

foraging are similar to the 

preferences for nesting.

 The most compelling evidence 

of declines in vertebrate abundance resulting from forest 

management practices is in 

cavity nesters owing to lack of 

nesting and foraging sites.

 Management that reduces 

snags includes short rotations 

and thinnings.

 Sustained provision of cavity 

trees may require creating cavity trees or snags, withdrawing 

a portion of the forest from 

management in the short term; 

incorporating aging trees into 

management in the long term; 

providing a minimum of two 

large snags per hectare and 

preferably four large snags per 

hectare with retention of some 

smaller snags for foraging. 

Retaining snags in patches is 

operationally efficient, safer, 

takes advantage of spatial 

clumping of dead trees, and 

seems effective in attracting 

cavity-excavating birds.

70 years old as a result of root rot. In natural forests, there is often 

a dearth of coarse woody debris recruitment between 40 and 150

years or so. 

Fallen trees—Pacific Northwest forests have the greatest coarse 

woody debris loads of any forests, and accumulated dead biomass is 

thought to be of central importance in promoting ecosystem stability, habitat diversity, and long-term productivity (Carey and Harrington 2001; Edmonds et al. 2000; Graham and Cromack 1982; 

Marra and Edmonds 1994, 1996). Functions of coarse woody debris 

include (1) nutrient cycling by adding organic matter to soil (Harmon et al. 1994, Sollins 1982); (2) microhabitats for a rich diversity 

of microorganisms, arthropods, lichens, and bryophytes and seedbeds for shade-tolerant conifers and ericaceous shrubs (Harmon et 

al. 1986, Peck et al. 1995); (3) refugia for mycorrhizal fungi and reservoirs of moisture during and after catastrophic disturbance, particularly on dry sites and during droughts (Amaranthus et al. 1989); 

(4) ectomycorrhizal links among trees and truffle production in lateseral forests (Amaranthus and Perry 1994, Amaranthus et al. 1994, 

Clarkson and Mills 1994); (5) niche diversification in small mammal 

communities by enhancing forest-floor structure, soil organic matter, fungi, and invertebrate communities (Carey and Johnson 1995); 

(6) habitat for salamanders (clouded salamander, Oregon slender 

salamander, and Ensatina) (Butts and McComb 2000, Corn and 

Bury 1991b, Gilbert and Allwine 1991); (7) foraging sites for pileated 

woodpeckers and their prey: ants (e.g., Camponotus, Formica, and 

Lasius spp.) (Torgersen and Bull 1995); (8) habitat element of primary importance to the western red-backed vole (Hayes and Cross 

1987, Tallmon and Mills 1994); (9) physical mediation of competition between blacktail deer and Roosevelt elk (Leslie et al. 1984); 

(10) elevated seedbeds that protect vascular plants from herbivory 

by ungulates; and (11) maternal den sites for arboreal rodents (Carey 

et al. 1997).

Of all the various elements of ecosystems, cover of fallen trees 

best described high-quality habitat for northern flying squirrels and 

Townsend’s chipmunk in southwestern Oregon (Carey et al. 1999b); 

15 percent cover might be optimal for mammals in wet to mesic 

forest, 10 percent cover in drier forests. Large fallen trees are almost 

twice as abundant in old growth as in managed forests, although 

the amount of coarse woody debris in second growth differs markedly with historical logging method and degree of legacy retention 

(Carey 1995, Carey and Harrington 2001, Carey and Johnson 1995). 

In the late 20th century, nearly complete removal of tree boles and 
306 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

intensive site preparation had resulted in less than 2 percent cover 

of coarse woody debris in many second- and third-growth forests 

(Carey et al. 1996a). Managed forests in general have less coarse 

woody debris than late-seral forests (Carey and Johnson 1995, Carey 

et al. 1999d, Spies and Cline 1988), but some, particularly on the 

western Olympic Peninsula, may have retained substantial biomass 

(Carey and Harrington 2001). Rebuilding a depleted store of coarse 

woody debris through retention of tree boles during thinning is possible but expensive (Carey et al. 1996a). Thus, legacy retention is especially important in setting the stage for conserving biodiversity in 

managed forests (Franklin et al. 1997).

Decadence as a process—If catastrophic disturbance sets the stage, 

it is small-scale disturbances in the canopy that determine the pace of 

the ecosystem development. Gaps drive the forest cycle in all forests 

(Whitmore 1989). The ecological process of tree death (Franklin et 

al. 1987) is particularly important in expansion of niche space (Carey 

1996, Carey et al. 1991, Parks and Shaw 1996, Stone et al. 1996). Only 

10 percent of the cells of living conifers are actually alive (Franklin et 

al. 1987). In eastern Washington and Oregon, four species of mistletoes, 50 species of rusts, and several rots play an important role in 

decadence (Parks and Flanagan 2001). Indeed, a case can be made 

that mistletoes are keystone species in forests and woodlands worldwide—97 vertebrate families consume mistletoes and 50 use them as 

nest sites (Watson 2001). Heart rots account for 20 to 31 percent of 

the volume of standing trees in Pacific Northwest forests (Hennon 

1995, Parks and Shaw 1996). Snapping of boles (often at the site of 

decay) and standing death constitute 76 percent of gapmakers; uprooting is the least common (21 percent) (Lertzman et al. 1996). In 

the Oregon Cascades, more than 70 percent of canopy Douglas-fir 

die standing or from stem breakage and die without disrupting the 

forest (73 to 88 percent of deaths in late-seral forest); only 12 to 27

percent of the trees in late-seral forests uproot (Spies and Franklin 

1989, Spies et al. 1990). In some mature forests, for example, mixedwood forests in Poland, windthrow is a major source of mortality for 

individual trees (Bobiec et al. 2000). Competition, however, is the 

major cause of death of conifers up to 150 years old (Franklin et al. 

1987). Mechanical damage from falling trees accounts for 15 percent 

of mortality in late-seral forests. Decaying and dead standing trees 

(1) increase structural diversity, (2) alter the canopy and understory 

microenvironments, (3) promote biological diversity, (4) store nutrients and decomposers, and (5) provide critical habitat elements for 

wildlife (Parks and Shaw 1996). The role of coarse woody debris in 
C H A P T E R 7 From Ecology to Forest Management 307

developing complex and productive forest floors and soils is generally accepted but poorly quantified.

Decadence and wildlife—The importance of standing dead trees 

(snags) and standing live trees with sufficient top rot to allow for 

formation or excavation of cavities by cavity-using birds and mammals has long been a focus of wildlife conservation, and the literature is large and diverse (Barkalow and Soots 1965, Bellrose et al. 

1964, Brewer 1961, Brown and Bellrose 1943, Conner et al. 1976, 

Dalke 1948, Davis et al. 1983, Dennis 1971, Erskine and McLaren 

1972, Fischer and McClelland 1983, Frank 1948, Gysel 1961, Kendeigh 1961, McClelland and Frissell 1975, Panicker 1980, Scott et 

al. 1977). The densities of cavity-using birds have been correlated 

with abundances of snags, especially snags over 50 centimeters in 

d.b.h. in the conifer forests of Oregon (Mannan et al. 1980), Washington (Zarnowitz and Manuwal 1985), and California (Raphael 

and White 1984). In southwestern Oregon forests, an abundance of 

large snags (more than 7 per hectare with greater than 50 centimeter 

d.b.h.) was the primary determinant of a diverse bird community 

(Carey et al. 1991). Large snags were 10 times more abundant, woodpeckers 4 times more abundant, and cavity-using birds as a group 2

times more abundant in old growth than in competitive-exclusion 

forests. Cavity-nesting birds constitute a majority of resident overwintering small-bird species. The keystone northern flying squirrel 

dens primarily in large, live old trees (presumably with heart rot and 

cavities) in old growth, but in residual old-growth snags in managed forests in southwestern Oregon (Carey et al. 1997). Cavities 

in large deciduous trees with top rot (e.g., bigleaf maple and Pacific 

madrone) also were used. Small-diameter conifer snags were rarely 

used for nesting by birds or mammals. In the Puget Trough, however, small-diameter deciduous snags (e.g., red alder) with cavities 

excavated by woodpeckers were important cavity sites in intensively 

managed second-growth stands with few large snags. In second 

growth with numerous well-decayed large snags and minimally decayed suppression mortality, flying squirrels resorted to stick nests 

in tightly closed canopies—but in both environments flying squirrel 

populations were low (Carey et al. 1997). On the Olympic Peninsula, flying squirrels denned in residual large snags and in cavities in 

live conifers with top rot (formed after tops were killed by freezing 

30 years previously) but not in abundant suppressed trees. It seems 

that suppression mortality in conifers does not contribute greatly to 

the function of standing decadent trees in either provision of cavities or gap formation. Small snags usually do not have top rot (or 
308 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

cavities) and do not stand very long; they do contribute to coarse 

woody debris on the forest floor for a relatively short time before 

decaying (Carey and Sanderson 1981 review of decay processes and 

cavity formation). The evolution of hole-nesting in birds (and arboreal rodents) is an adaptation that allows year-round residence 

in temperate forests by providing bioenergetic advantages and protection from predation (Collias 1964, Short 1979). Flying squirrels 

have evolutionary adaptations of gliding, nocturnality, cavity-nesting (Holmes and Austad 1994), and communal denning (Carey et al. 

1997). Nocturnal arboreal travel and gliding have energetic costs that 

are offset (37 percent reduction in heat loss) by denning in groups 

in cavities lined with plant material (Carey et al. 1997, Stapp et al. 

1991). Thus, den sites large enough to hold more than three squirrels 

are important, and decay in the tops of large trees is important. In 

addition, flying squirrels change dens about every 2 weeks (perhaps 

as a strategy to avoid predators) and large numbers of group dens are 

needed (Carey et al. 1997).

There is a broad correspondence between large snag abundance 

and population sizes of flying squirrels across the Pacific Northwest 

(Carey 1995). This correspondence, however, is more likely a result 

of large snags as indicators of overall decadence than to provision 

of den sites (Carey et al. 1997). Trees display a continuum of roles 

from living, sound organisms to dead, prostrate structures on the 

forest floor (Franklin et al. 1987). Many of these roles depend on decay forming in living trees of large size; for example, hollow trunks 

of fallen trees used as dens by American marten. Thus, decadence 

in Pacific Northwest forests cannot be partitioned functionally into 

snags and fallen trees without losing the significance of the entire 

process of tree decay and death and its diverse functions. This is 

especially true in relation to the role of accumulated organic matter 

on the forest floor. Fallen trees transform into rotting logs, humus, 

and organic soil formed through the action (digestion of wood and 

mechanical mixing of the soil) of invertebrates. Forest-floor organic matter influences a variety of life forms in the forest floor, and 

its role relative to ectomycorrhizal fungi essential to the growth of 

many trees and their production of truffles (the food of many mammals that are prey for vertebrates higher on the food chain) has been 

the subject of much discussion and speculation.

Fallen trees and truffles—What accounts for the ability of decadence to explain variation in space use, activity, and abundance of 

flying squirrels and other small mammals? It is plausible that the role 

of decadence in providing den sites is important for an abundance 
C H A P T E R 7 From Ecology to Forest Management 309

of flying squirrels (Carey 1995, Carey et al. 1997), but abundance of 

fallen trees predicted flying squirrel abundance almost as well as did 

decadence (which includes snags as well). Fungal sporocarps (truffles) compose the bulk of the diet of the flying squirrel, and a strong 

connection has been made between truffle abundance and coarse 

woody debris in southwestern Oregon. Truffle abundance is 20 to 30

times greater in old forest with more than 25 percent cover of coarse 

woody debris than in young plantations with less than 15 percent 

cover of coarse woody debris (Amaranthus et al. 1994). Within old 

forests in drier parts of the Pacific Northwest, truffles are 10 times 

greater in well-decayed fallen trees than in mineral soil. Of the eight 

genera that are common in flying squirrel diets (Carey et al. 2002, 

1999b), five (Rhizopogon, Melanogaster, Leucophleps, Hysterangium, 

and Leucogaster) were associated with well-decayed coarse woody 

debris (Amaranthus et al. 1994). Only Elaphomyces (the eighthranked genus in diets of flying squirrels) was associated primarily 

with mineral soil. Balsamia, the eighth-ranked genus in chipmunk 

diets (and not present with more than 5 percent frequency in flying 

squirrel pellets), also was associated with mineral soil. Clarkson and 

Mills (1994) also found sample plots with fallen trees are more likely 

to contain sporocarps (twice as likely) and on average to have more 

biomass (four times more) of sporocarps than sampling plots without fallen trees in late-seral forest in southwestern Oregon. They 

found that activity of mycophagous western red-backed voles is associated with truffle abundance and coarse woody debris. Of the 

five most abundant genera (Melanogaster, Hysterangium, Gautieria, 

Genebea, and Rhizopogon) found by Clarkson and Mills (1994), four 

were among the five most abundant in diets of flying squirrels, and 

three were among the five most abundant in diets of Townsend’s 

chipmunk as well. 

Flying squirrels consume 20 to 24 genera of fungal sporocarps 

year-round (Carey et al. 2002, 1999b; Maser et al. 1986). Rhizopogon, 

Gautieria, Hymenogaster, Melanogaster, Hysterangium, Leucophleps, 

Elaphomyces, and Geopora are the dominant items in spring diets. 

Seasonal differences in diets include high frequencies of Elaphomyces in January-February, decreased frequencies of Hymenogaster in 

summer-fall, and increased frequencies of Leucogaster in summerfall; lichens are important dietary components in January. Diets of 

northern flying squirrels in the Pacific Northwest differ geographically, but fungal sporocarps still compose the bulk of diets. In the 

relatively dry forests of northeastern Oregon and California, flying 

squirrels consume less fungus and more lichen, plant material, and 

staminate cones than flying squirrels in western Oregon (Carey et al. 
310 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

1999b; Maser et al. 1985, 1986; Waters and Zabel 1995). Rhizopogon

still dominates the diet, flying squirrel densities are positively correlated with sporocarp abundance, and fungal sporocarps are twice 

as abundant in old-growth white fir as in competitive-exclusion 

stands 75 to 95 years old with little coarse woody debris (Waters 

and Zabel 1995). In the western Washington lowlands, flying squirrels consume 16 of 21 genera and 40 of 50 species of mycorrhizal 

fungi found in second-growth Douglas-fir forest (Carey et al. 2002, 

1996b). Rhizopogon, Melanogaster, Hysterangium, Endogone, and Leucogaster are the genera most frequently encountered in the soil, and 

Rhizopogon, Gautieria, Leucogaster, and Melanogaster are the common spores in diets. Gautieria was most abundant in stands with 

high coarse woody debris loads, and Melanogaster was most common in stands with little coarse woody debris. Flying squirrels were 

more than twice as abundant in forests with 6 to 8 percent coarse 

woody debris than in forests with less than 2 percent coarse woody 

debris. Mushroom spores (Russula, Peziza, Agaricaceae, and Boletaceae) were common in diets; plant material and lichens were relatively infrequent in fecal pellets. Spring diets of flying squirrels in 

Douglas-fir-western hemlock forests on the Olympic Peninsula of 

western Washington are dominated by Rhizopogon, Hysterangium, 

and Leucogaster. Olympic Peninsula squirrels also consume spores of 

Boletaceae, Octaviana, Thaxterogaster, and Chamomixia (Carey 1995). 

Dietary species richness on the Olympic Peninsula is half that in the 

Oregon Coast Range (Carey 1995, Carey et al. 1999b) and differs 

between competitive-exclusion and old-growth forest; but coarse 

woody debris is not a good predictor of flying squirrel abundance 

on the Olympic Peninsula. Several differences between the Oregon 

Coast Range and the Olympic Peninsula can explain the differences 

in dietary diversities and influence of coarse woody debris. 

The Olympic Peninsula has more precipitation, cooler temperatures, and less severe summer drought than the Coast Range; coarse 

woody debris is generally abundant (Carey and Harrington 2001), 

and thus coarse woody debris may not be important as moisture reservoirs and refugia for ectomycorrhizal fungi. Coarse woody debris 

loads on the Olympic Peninsula are higher (8 percent in competitive exclusion, 13 percent in old growth) than in the Coast Range (4

percent in competitive exclusion, 9 percent in old growth), forestfloor organic matter accumulations are greater, and forest floors are 

moister (Carey and Johnson 1995). Forests on the Olympic Peninsula are dominated by western hemlock, which does not have as 

many ectomycorrhizal associates as Douglas-fir. Few species are specific to western hemlock, which may have evolved to capitalize on 
C H A P T E R 7 From Ecology to Forest Management 311

the mycorrhizal associations of pioneering species (e.g., Douglasfir) that establish quickly after catastrophic disturbance (Molina et 

al. 1992). Thus, mycorrhizal diversity (and possibly sporocarp abundance) may be relatively low in pure western hemlock competitiveexclusion stands. About 50 species associate with western hemlock 

in the laboratory, more than 100 species in the field (Kropp and 

Trappe 1982, Molina et al. 1992, Molina and Trappe 1982). There are 

250 species that are specific to, and 2,000 species associated with, 

Douglas-fir (Molina et al. 1992). 

In southwestern Oregon, giant chinquapin, Pacific madrone, 

tanoak, and salal are broadly receptive to numerous ectomycorrhizal 

fungi, form ectomycorrhizal associations that facilitate establishment of conifers after catastrophic disturbance, and create spatial 

and temporal ectomycorrhizal links among tree species (Amaranthus and Perry 1989, 1994; Molina et al. 1992; Molina and Trappe 

1982; Smith et al. 1995). Thus, it is not surprising that there are not 

differences in dietary diversity between squirrels from competitive 

exclusion and squirrels from old growth in the Coast Range. In 

summary, dietary diversity was associated with coarse woody debris 

sometimes, but activity of mycophagous mammals and truffle abundance in southwestern Oregon seem to be strongly associated with 

coarse woody debris. 

Management affects composition of truffle communities in various ways (Carey et al. 2002). More species and genera are found in 

soil and in feces in forests with old-growth legacies than in thinned 

forests managed without consideration for legacies or decadence. 

Second-growth forests in the Puget Trough had 48 species (Colgan et al. 1999). Broad surveys of managed and old-growth forests 

found 43 species in western Washington (North et al. 1997) and 

47 species in Oregon (Luoma 1991). Because total truffle production differs markedly among seasons and years (e.g., 330 to 1,852

grams per hectare) and species production differs even more markedly, often more than tenfold (Luoma 1991), taxonomic diversity is 

important in providing a consistent food supply to mycophagous 

mammals. Total truffle diversity, however, differs little among the 

physiographic provinces of western Oregon and Washington, but 

the northern forests of the Olympic Peninsula and North Cascades 

forests seem to have greater dominance by a single species than forests in the Puget Trough or in Oregon (Carey et al. 2002). Flying 

squirrel diets were rich in Puget Trough legacy forests (seven commonly occurring genera) compared to similarly managed forests on 

the Olympic Peninsula (four genera) and similar in diversity to diets 

in old-growth forests on the peninsula (six genera). Diets in thinned 
312 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

forests in the Puget Trough had the same number of genera (four) 

as diets in the legacy forests on the peninsula. Flying squirrel diets in 

the Puget Trough and on the Olympic Peninsula had fewer genera 

than flying squirrel diets from the warmer, drier, southern Oregon 

Coast Range (12 genera in old growth and 9 in extensively managed 

forests) (Carey 1995, Carey et al. 1999b). 

Truffle production is important to mycophagous animals. Flying squirrel abundance varied with truffle abundance in northeastern California (Waters and Zabel 1995). In southwestern Oregon, 

local foraging by flying squirrels was correlated with abundance of 

coarse woody debris (Carey et al. 1999b), and coarse woody debris 

was positively correlated with truffle abundance (Amaranthus et al. 

1994). Even though 20 to 50 species of hypogeous fungi may be 

present in any one stand, usually fewer than five species account 

for the bulk of the biomass of sporocarps (Amaranthus et al. 1994, 

Carey et al. 2002, Colgan et al. 1999, Fogel 1976, Fogel and Hunt 

1979, Hunt and Trappe 1987, Luoma 1991, North et al. 1997). These 

abundant fungi, however, are the ones most frequently tallied in 

squirrel diets and seem to be narrow (tree genus) to intermediate 

(tree family) in host range (Molina et al. 1992, Molina and Trappe 

1982). Four genera common in flying squirrel diets across the Pacific 

Northwest (Carey 1995, Carey et al. 1999b), Gautieria, Leucogaster, 

Leucophleps, and Elaphomyces, were less abundant in soil or feces in 

thinned forests than in forests with legacies of coarse woody debris. 

Production of truffles by Gautieria (and Hysterangium) is reduced 

by thinning in the short term (Colgan et al. 1999) and, apparently 

with conventional thinning, that effect is long lasting but not universal for species of Hysterangium. For example, H. coriaceum and 

H. crassirhachis were more abundant in forests with legacies and H. 

setchellii was more abundant in thinned forest—an example of the 

resilience of the ectomycorrhizal community resulting from species 

diversity (and redundancy) within a functional group. Leucogaster citrinus and Elaphomyces granulatus are listed as late-seral species (Castellano et al. 1999, USDA and USDI 1994) and are common in legacy 

forest but not in conventionally thinned forest, demonstrating that 

legacy retention can be important in maintaining functional group 

and species diversity through intentional management disturbances. 

Moreover, 71 late-seral epigeous (mushroom-producing) fungi also 

occurred in second-growth forests in the Puget Trough (Carey et 

al. 1999d). Fruiting of Melanogaster, like H. setchellii, was favored by 

thinning (Colgan et al. 1999); Melanogaster truffles were six times 

more frequent in soil and twice as abundant in flying squirrel feces 

in thinned than in legacy forest. On the other hand, three of four 
C H A P T E R 7 From Ecology to Forest Management 313

Rhizopogon species occurred only in thinned forest. Several species 

of Rhizopogon are associated with early stages of forest development 

and are often abundant on tree roots following disturbance (Molina et al. 1997). Several factors may explain low truffle production 

by certain species in thinned forest. Species that form hyphal mats 

may be more susceptible to mechanical damage by logging operations. Thinning may change microclimate to the detriment of these 

species. Hysterangium and Gautieria were reduced in abundance in 

shelterwood stands 17 and 20 years after timber harvest (Waters 

et al. 1994). Gautieria mats were found only in the rooting zone of 

retained old-growth trees 2 years after a shelterwood harvest in the 

Oregon Cascades (Aguilera et al. 1993), and Hysterangium spores 

were rare in feces of Siskiyou chipmunks in shelterwood stands in 

southwest Oregon (McIntire 1984). Shelterwood harvests remove 

a greater proportion of trees than thinning, and considerable time 

may be required after disturbance for such taxa to recover and fruit. 

North and Greenberg (1998) hypothesized that reduction in biomass of E. granulatus in managed compared to natural old forests 

was a consequence of reduction of thick organic layers with high 

root density in managed forests. Rhizopogon parksii, the other species they studied, was not associated with organic layers. The areas 

studied by North (North and Greenberg 1998, North et al. 1997) are 

on the cool, moist end of the Western Hemlock Zone. At the opposite extreme (hot, dry) in southwestern Oregon, Amaranthus et al. 

(1994) found a close association between truffles of various species 

and decaying logs on the forest floor.

Truffle abundance, although important to mycophagous mammals, is but one of several important factors. On the Olympic Peninsula, flying squirrel abundance was correlated more with understory development (Carey 1995) and abundance of mast-bearing trees 

(vine maple and bigleaf maple)—ancillary sources of high-quality 

food—than with coarse woody debris (Carey and Harrington 2001). 

Flying squirrels were almost twice as abundant in legacy as in conventionally thinned forest, whereas chipmunks were four times more 

abundant in thinned forest (Carey 2000b, 2001). Food and cover well 

explain differences in chipmunk abundance (Carey 2000b, 2001) but 

not differences in flying squirrel abundance, given that (1) truffle 

biomass was equal in the two forest types, (2) flying squirrels consumed all species of truffles present (Carey et al. 2002, Colgan 1997, 

Colgan et al. 1999), (3) truffles are nutritionally poor (Claridge et 

al. 1999, Cork and Kenagy 1989), and (4) vascular plant parts consumed by flying squirrels (Thysell et al. 1997b) have high nutritive 

value (Cork and Kenagy 1989). Locally, flying squirrel abundance 
314 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

may be determined by (1) availability of dens (Carey 2001, Carey 

et al. 1997), (2) habitat-mediated predation (Carey et al. 1992, Wilson and Carey 1996), (3) competition with chipmunks and Douglas’ 

squirrels in environments simplified by forest management (Carey 

and Harrington 2001), and (4) ancillary food sources (Carey and 

Harrington 2001, Ransome and Sullivan 1997, Thysell et al. 1997b). 

Studies suggest the hypothesis that simultaneously high populations 

of northern flying squirrels, Townsend’s chipmunks, and Douglas’ 

squirrels in the Douglas-fir keystone complex—a characteristic of 

old, natural forests (Carey 1995)—results from ecological processes 

of development of habitat breadth and niche diversification (Carey 

et al. 1999b) and not a single limiting factor (Carey 2001, Carey and 

Harrington 2001) or single limiting process.

The chemical composition of truffles suggests high food value 

(Fogel and Trappe 1978), but digestibility of truffles is low, near the 

minimum for maintenance of squirrels (Cork and Kenagy 1989). 

Truffle genera differ in digestibility, different taxa provide different 

nutrients to squirrels, and squirrels differ in ability to extract nutritive value from truffles (Townsend’s chipmunk is less capable of 

extracting nutrients from truffles than the northern flying squirrel). 

Thus, dietary diversity may be important for nutritional adequacy. 

Great abundance, high detectability (through odors that attract 

squirrels), and low handling time for truffles maximize net yield of 

energy and nutrients to squirrels, but a high-quality diet requires 

more than just truffles (Cork and Kenagy 1989). Squirrels eat a wide 

variety of truffles and mushrooms and, sometimes, vascular plant 

material (especially seeds and other reproductive parts). Townsend’s 

chipmunk and Douglas’ squirrel eagerly consume conifer seeds as 

well as seeds and fruits of other plants and fungi (Maser et al. 1978, 

Smith 1970, Sutton 1993). Across their range, northern flying squirrels consume a wide variety of lichens, nuts, seeds, fruits, staminate 

cones, and catkins (Wells-Gosling and Heaney 1984) but not much 

conifer seed. Flying squirrels in the West primarily are mycophagous 

year-round, although lichens are important winter foods in some areas (Carey 1995; Carey et al. 2002, 1999b; Currah et al. 2000; Maser 

et al. 1985, 1986; Rosentreter et al. 1997). Flying squirrels may consume 15 grams of truffle in a single meal; stomach contents (mostly 

spores) may weigh 24 to 71 grams for squirrels with a live mass of 

152 to 165 grams. But even relatively small amounts of high-quality food are nutritionally significant to squirrels given the low food 

value of truffles (Cork and Kenagy 1989). Thus, flying squirrels are 

not strictly mycophagous, even though fungi dominate their diets. 

Flying squirrels and chipmunks eat lichens, mushrooms, staminate 
C H A P T E R 7 From Ecology to Forest Management 315

cones, pollen (e.g., cottonwood), seed (e.g., bigleaf maple; conifer 

seed by chipmunks), and fruits (e.g., salal) in addition to truffles.

Importance of soil organic matter and fungal diversity—Fungal 

diversity does more than provide diverse diets for squirrels. Fungi are essential in many food webs; their exudates and hyphae link 

above- and belowground processes by providing photosynthetically 

fixed carbon to rhizosphere consumers such as bacteria, protozoa, 

and arthropods. Roots and mycorrhizal symbionts account for 70

to 80 percent of net primary productivity; 10 to 40 percent of total 

photosynthates pass from roots to rhizosphere adding organic material to the soil and enhancing soil structure. Diversity in mycorrhizae provides resilience to environmental stresses and may extend the 

range of environments within which plants can prosper (Perry et al. 

1989). Each fungal species is thought to have its own set of physiological characteristics; thus, their activity differs with temperature 

and moisture, and they differ in the nutrients they extract from mineral soil and organic matter (Molina et al. 1992, Molina and Trappe 

1982, Perry et al. 1989). Diversity in the plant community can be 

quite important in stabilizing belowground mutualists after catastrophic disturbance (Perry et al. 1989). Although much of the composition of plant communities in Pacific Northwest forests is a result 

of the processes of canopy stratification and understory development, ectomycorrhizal linkages among plants can reduce competition for resources, promote forest recovery after disturbance, and influence the pattern of plant succession (Amaranthus and Perry 1994, 

Molina and Amaranthus 1991). Thus, forest-floor structure, plantcommunity composition, fungal-community composition, and animals interact in mutually reinforcing ways to produce ecosystem 

resilience and development. Overall, biodiversity stabilizes community and ecosystem processes, if not population processes (Tilman 

1996).

Canopy Stratification

Jerry Franklin likes to say that forests mature like men do—the living biomass progressively slips downward (see also Massman 1982). 

Processes leading to transfer of foliage abundance from overstory 

to midstory and understory and even the occurrence of a midstory 

differ among seral stages (fig. 66). In competitive exclusion, a sparse 

midstory may develop when conifers grow taller than their deciduous contemporaries. This midstory contributes little to foliage-height 
Foliage-height 

diversity

Overstory

Midstory

Shrub

Herbaceous

2.45

45

43

27

40

2.67

49

48

29

2.10

44

62

14

34

24

OG ND CE

316 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 66—Foliage-height 

diversity profiles showing the BergerParker index and percentage of covers 

(in boxes) by vegetation layers for 

old-growth (OG), niche-diversification (ND), and competitive-exclusion 

(CE) stages in Oregon Coast Range, 

1986–87 (Carey et al. 1999b). The 

Berger-Parker index is a scientific 

measurement for foliage-height diversity—the larger the number, the larger 

the diversity in vegetation layers.

diversity and seems coincidental with understory development (Carey et al. 1991, 1999b). However, portions of some 40- to 70-year-old 

stands in the Oregon Coast Range had high foliage-height diversity; these were used for roosting by the northern spotted owl (Carey 

et al. 1992). In niche diversification, stratification occurs as a result 

of (1) retention of live old trees and possibly advance regeneration 

from previous stands, (2) development of a predominant even-aged 

cohort of conifers of mixed species following catastrophic wildfire 

(say 100 years before), (3) establishment of deciduous trees following 

catastrophic wildlife, and (4) subsequent establishment of a third 

cohort of conifers (including Douglas-fir) after noncatastrophic 

wildfires. Foliage-height diversity is great, distributed among midstory, overstory, and herbaceous cover with mean values about 45

percent with shrub cover lower, less than 30 percent. Mean midstory 

cover is much greater than in competitive exclusion (less than 15

percent) and similar to old growth (also 45 percent). Early histories 

of old-growth stands are generally unknown or only partially explicable from dendrochonology (Tappeiner et al. 1997). Nevertheless, 

in southwestern Oregon, 210- to 350-year-old overstories were a 

mix of species, and midstories were primarily shade-tolerant conifers, bigleaf maple, and Pacific madrone. In the Coast Range, bigleaf 

maple is most abundant in old growth (Carey et al. 1999b, Spies 

1991). Shade-tolerant conifers in the overstory (western hemlock, 

western redcedar, incense-cedar, grand fir) often are contemporaries 

of the dominant Douglas-fir and a result of midstory trees gradually 
C H A P T E R 7 From Ecology to Forest Management 317

entering the canopy. Midstories tend to merge with overstories and 

understories in old growth; foliage-height diversity is high. 

Development of high foliage-height diversity and spatial heterogeneity in forest plant communities depends on growth of shadetolerant tree seedlings in the understory into the midstory. Light is 

usually the factor limiting seedling development on moist, fertile 

sites, but root competition for nutrients and moisture among various plants may occur on dry and infertile sites (Coomes and Grubb 

2000). Dry woodlands allow 20 times more light to penetrate than 

wet forests do. Both overstory trees and understory shrubs influence seedling recruitment in ponderosa pine forests (Keyes et al. 

2001). Thus, germinants, seedlings, and saplings exhibit significant 

spatial aggregation. A high prevalence of patches of dense shrub 

cover in niche-diversification west-side Douglas-fir forest may be 

due to intermediate-scale disturbances (tree-fall gaps, small wildfires, windthrow, ice storms). Silvicultural thinning has the potential 

to promote growth of the retained dominants while encouraging 

growth of shade-tolerant trees in the midstory; the density of retained trees, the timing of multiple entries, and the sizes and crown 

classes of trees being removed can be varied as appropriate to forest 

type and local conditions, while also creating spatial heterogeneity 

and recruiting dead wood to the forest floor (Carey 1995, 2003a, 

2003c; Carey and Johnson 1995; Carey et al. 1999b, 1999c; Garman 

et al. 2003). 

Deeply layered vegetation in old growth and niche diversification results in cool and humid conditions in the understory and 

protection from radiation and drying winds; moistness of forest also 

increases with amount of decomposing wood (Spies 1991). Thus, 

late-seral forests have greater covers of herbaceous plants and more 

diverse shrubs than competitive-exclusion forest. Complexity of 

structure and resulting variety in microclimates results in greater 

numbers of plant species and greater percentage of cover per species 

than in homogeneous stands (Carey 2003a; Carey and Curtis 1996; 

Spies 1991; Thysell and Carey 2000, 2001a). Deciduous tall shrubs 

and trees, in particular, add substantially to biodiversity by providing 

foliage for consumption by insects (especially moths and butterflies, 

whose larvae are eaten by birds and terrestrial insectivores), an architecture hospitable to lichens, and fruits (flowers, catkins, seeds, and 

nuts) of high food value for insects, birds, and mammals (Bunnell et 

al. 1999, Carey 2000a, Muir et al. 2002). Thus, complexity and species diversity translates into habitat breadth and preinteractive niche 

diversification. Habitat breadth accounts for more variation in small 

mammal activity than does decadence (Carey and Harrington 2001, 
318 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Carey et al. 1999b). Canopy stratification, however, was the single 

best descriptor of the realized habitat of chipmunks. Midstory cover 

had the most predictive power for chipmunk activity. Decadence 

and canopy stratification seemed of nearly equal importance in explaining variance in chipmunk carrying capacity. Although canopy 

stratification explained only 11 percent of the variance in vegetation 

structure among points, its process seemed to have profound influences on the plant and squirrel communities.

Gaps and stratification—In older forests, development of diversity in vegetation structure and composition stems from small-scale, 

gap-forming processes (Poulson and Platt 1989). In coastal temperate rain forests, over 50 percent of the forest area is influenced by 

canopy openings due to the death of 1 to 10 trees (Carey et al. 1999b, 

Lertzman et al. 1996, Spies and Franklin 1989, Spies et al. 1990, 

Stewart 1986). Tree-crown overlap in old growth averages only 15 to 

30 percent. The median size of gaps is less than 100 square meters in 

old growth but less than 20 square meters in mature forest (Spies et 

al. 1990). Death of 5 to 10 large, adjacent trees, although rare, would 

cause gaps of 1,100 square meters. Gaps more than 0.1 hectare and 

relative tree densities more than 3.5 promote seedling growth in 

the understory (Brandeis et al. 2001, Coates 2000). Gaps are rare in 

competitive-exclusion and biomass-accumulation stages, although 

diseases like root rot can form small to moderately sized gaps. 

Overlap among tree crowns in old growth is due in large part to 

subdominant western hemlock (Spies et al. 1990). This development 

of midstory vegetation maintains connectivity among tree crowns 

that facilitates travel by arboreal rodents (Carey 1996). Full foliageheight profiles, found in niche diversification and old growth, facilitate exit from and entry to the canopy by providing protection 

from predation associated with gliding over open areas and with 

tall expanses of clear tree boles characteristic of competitive-exclusion forests (Holmes and Austad 1994, Stapp 1994). Stratified 

canopies provide increased niche space for summer and winter birds 

(Carey et al. 1991, Shaw and Flick 1999). For chipmunks, the value 

of midstory might be in variety and abundance of seed production 

by conifers, hardwoods, and understory shrubs. To the benefit of all 

squirrels, gaps may result in increased fungal production through 

extended root networks of the dominant Douglas-fir, ameliorated 

microclimate, increased habitat breadth, niche diversification in the 

forest floor, and ectomycorrhizal linkages among Douglas-fir, western hemlock, grand fir, and coarse woody debris (Molina and Amaranthus 1991, Perry et al. 1989). Furthermore, gaps create a mosaic 
C H A P T E R 7 From Ecology to Forest Management 319

of open and closed canopy that promotes a mosaic of understory 

vegetation site types, including areas of high foliage-height diversity. 

This mosaic affords a modicum of protection to small mammals in 

areas of heavy cover and opportunities for foraging by predators in 

more open areas (Carey et al. 1992). Thus, gap formation and canopy 

stratification are prerequisite to development of complex understories.

Understory Development

In the Pacific Northwest, succession of early seral communities, 

from the catastrophic release of ecosystem resources to tree canopy 

closure, depends on the biological legacies retained during disturbance, the degree of soil disturbance, and colonization by ruderals. 

Succession may be quite variable—a slow progression from herbs 

to shrubs to trees—with years, or even decades, in between stages, 

to quick occupancy by conifers. With invasion by grasses, the soil 

ecology may become dominated by bacteria instead of fungi, and a 

long delay may occur before trees become established. On the other 

hand, joint establishment of multiple life forms is common, and 

there are strong and predictable relationships between herbs and 

woody plants (McKenzie et al. 2000a). In some cases, deciduous 

trees may grow quickly and suppress conifers; in other cases, when 

both are present, conifers may eventually grow through and overtop the deciduous trees. In most cases, trees, by virtue of sustained 

growth, longevity, and size, quickly dominate the site (Halpern and 

Franklin 1990, Halpern and Spies 1995, McKenzie et al. 2000a). In 

Alaska, alder-conifer mixes maintain a species-rich and abundant 

understory, even compared to old growth. Herbs and shrubs increase 

after logging then virtually disappear if the tree canopy is dominated 

by conifers; the understory may remain depauperate for more than 

100 years (Hanley, in press). Light precommercial thinning can produce a short-lived increase in shrubs with a slight increase by herbs, 

especially forbs; heavier thinnings offer more promise of promoting 

understory that is favorable to other life forms, such as deer; but 

if thinnings are too heavy, producing over 60 percent full sunlight, 

then western hemlock will regenerate. Depending on tree density, 

the tree canopy may quickly close or slowly close but often, without 

disturbance, the end result is a stage of competitive exclusion with 

little understory. Sooner or later, the understory will begin to develop. 

Thus, in areas where trees become well established, understory development contributes relatively little (10 percent) to the variance in 
320 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

forest vegetation. In the relatively dry Oregon Coast Range, much of 

the differences among stands and seral stages in understory development seemed related to relative abundance of ferns and shrubs and 

to composition of the shrub community (Carey et al. 1999b). Most 

competitive-exclusion stands have salal as a component of the shrub 

layer, with 1 to 3 other species, particularly oceanspray, California 

hazel, or huckleberry, present in small quantities. Herbaceous layers 

are dominated by moss, oregongrape (as a low, prostrate shrub), and 

swordfern (Thysell and Carey 2000). Natural and silvicultural thinning can promote diversity and growth in understory (Muir et al. 

2002; Tappeiner and Zasada 1993; Thysell and Carey 2000, 2001a) 

with profound effects on food webs (Carey 2003a, Hayes et al. 2003, 

Muir et al. 2002). In niche diversification and old growth, however, 

Pacific rhododendron, vine maple, and conifer seedlings and saplings were added to salal, oceanspray, and huckleberries. A diversity 

of species and growth forms occurred in the herbaceous layer: low 

shrubs, half-shrubs, ferns, forbs, grasses, and mosses. Nonetheless, 

few plant species in Pacific Northwest coniferous forests are confined to a particular seral stage (Carey et al. 1999b, Franklin and 

Dyrness 1973, Spies 1991). 

Abundances of vascular plants and community diversity increase 

with stage of forest development (Halpern and Spies 1995, Spies 1991, 

Stewart 1986). Four processes influence understory development: (1) 

resource availability, (2) horizontal spatial heterogeneity, (3) vertical 

diversity of vegetation, and (4) fire (Carey et al. 1999b, Spies et al. 

1990). Aggressive shrubs of low to moderate shade tolerance (e.g., 

salal) form dense patches under uniform, open canopies (Thysell 

and Carey 2000, 2001a). In tall old-growth and niche-­diversification 

forests, shade-tolerant species are favored. Old-growth understories 

tend to be relatively cool and humid during dry seasons because they 

are protected from radiation and drying winds by deep, multiple, 

canopy layers. Accumulated coarse woody debris and litter on the 

forest floor act as moisture reservoirs. Gaps in canopies provide 

marked horizontal heterogeneity in the spatial distribution of light 

and moisture. Sunflecks of brief duration contribute 37 to 68 percent 

of total photosynthetically active radiation (Canham et al. 1990). 

Penetration of light into the understory adjacent to gaps is significant 

at high latitudes because of sun angle. Even though the mean and 

range of light levels increase with size of gaps, potential duration of 

light is still below 4 hours and varies inversely with canopy height 

(70 meters in old-growth Douglas-fir). Development of shadetolerant midstories can have significant impacts on the amount of 

light reaching the understory. Light penetration also differs with 
C H A P T E R 7 From Ecology to Forest Management 321

gap orientation; north-south gaps admit more light than east-west 

gaps (Poulson and Platt 1989). Changes in topographic position and 

edaphic gaps increase heterogeneity in light conditions, and, with 

30 percent of the forest area in gaps, 56 percent of the forest area is 

influenced by canopy openings (Lertzman et al. 1996). 

Understory development influences animal populations. For example, understory development is a minor but significant predictor 

of the realized habitat of flying squirrels, chipmunks, and many other 

small mammals (Carey 1995, Carey and Harrington 2001, Carey and 

Johnson 1995, Carey et al. 1999b, Carey and Wilson 2001). Chipmunks increasingly select home ranges with heavy understory as 

midstory decreases (that is, from old growth to niche diversification 

to competitive exclusion). The prevalence of patches of ericaceous 

shrubs also is correlated with abundances of both flying squirrels 

and Townsend’s chipmunks on the Olympic Peninsula. Ericaceous 

shrubs, snags, and the nature of the catastrophic disturbance originating the stand explained 85 percent of the variance in flying squirrel activity. Patches of ericaceous shrubs covered about 40 percent of 

flying squirrel habitat. In the middle Oregon Coast Range, abundance of chipmunks across the early stages (ecosystem reinitiation 

to understory reinitiation) is highly correlated with abundance of 

salal but no other habitat variables (Hayes et al. 1995). Three explanations exist for correlation with ericaceous shrubs: (1) the fruits of 

the shrubs provide food, (2) shrubs provide cover from predation, 

and (3) shrub cover is correlated with some other determinant of 

chipmunk abundance. The importance of overhead cover to chipmunks has been experimentally demonstrated (Harestad 1991).

Development of Habitat Breadth

Legacies, the four basic structuring processes of crown-class differentiation, decadence, canopy stratification, and understory development, and spatial heterogeneity combine to allow an emergent, or 

second-order, process to unfold. This process is development of habitat breadth and it consists of the development of a fine-scale (less 

than 0.2 hectare) mosaic of vegetation patches (or vegetation site 

types) that differ in species composition, vertical diversity in foliage 

abundance (foliage height profiles), and in the types and abundance 

of food and cover available to animals. In southwestern Oregon, 

spatially complex light, temperature, and moisture conditions produced 21 of these small patch types related in part to (1) landscapelevel climatic gradients; (2) among-stand variation in environmental 
322 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

conditions owing to slope, aspect, elevation, edaphic conditions, and 

stage of forest development; and (3) within-stand variation owing to 

site moisture, edaphic gaps, regeneration gaps, canopy gaps caused 

by tree death, and development of shade-tolerant midstories. All site 

types were found across most stands, suggesting types were more 

a product of ecosystem development conditioned by temperature 

and moisture rather than unique local phenomena. Site types can be 

used to measure fine-scale heterogeneity (degree of development of 

habitat breadth) arising from disturbance and forest development. 

Habitat breadth is also an index to biological diversity because diversity of fine-scale patches of vegetation influences fungal, invertebrate, and vertebrate diversity through abundance and diversity of 

food and cover and ameliorated microclimates (Carey et al. 1999b, 

Colgan et al. 1999, Schowalter et al. 2003). Fine-scale environmental 

heterogeneity that promotes biological diversity also is likely to foster 

mutualisms (Bronstein 2001) as well as mitigating competition and 

predation. The phenomenon of increased diversity and abundance 

across all major life forms following increased forest complexity (increased numbers and lengths of axes of the unrealized [unexploited] 

niche space) is the result of the emergent property, preinteractive 

niche diversification (Hutchinson 1978) (figs. 67, 68). Development 

of habitat breadth and niche diversification work against one or two 

species dominating a functional group and promote the coexistence 

of species—for example, green-tree retention in variable-retention 

harvest units in British Columbia helped prevent an irruption of 

Oregon creeping voles and allowed southern red-backed voles to remain moderately abundant throughout the reorganization and early 

development of the ecosystem (Sullivan and Sullivan 2001). In western Washington, species common during ecosystem reorganization 

but usually rare to missing in spatially homogeneous competitive 

exclusion and biomass accumulation stages are also present in experimental gaps (Gitzen and West 2002), second growth with managerially induced understory reinitiation (Wilson and Carey 2000), 

and old, natural forests (Carey and Johnson 1995). Thus, differences 

in habitat breadth along with differences in decadence can explain 

as much as 50 percent of the variance in flying squirrel activity and 

70 percent of the variance in habitat quality. 

The roles of different ecological factors differ among biotic communities and even within biotic communities that are environmentally heterogeneous. For example, vegetation heterogeneity plays a 

dominant role in insect population dynamics and community structure, both of which are important to insectivorous birds and mammals. Differences among species within a trophic level, differences 
Seed-producing deciduous trees 

Low evergreen shrubs 

Tree size and decadence 

Townsend’s

chipmunk

optimum niche

Northern

flying squirrel

optimum niche

C H A P T E R 7 From Ecology to Forest Management 323

Figure 67—Through preinteractive niche diversification, there is an 

expansion of overall niche space and 

niche dimensions (evergreen shrubs, 

seed-producing deciduous trees, large 

conifers, decadence, etc.), providing a 

greater separation of species niches as 

well as creating more space available 

for a greater number of individual 

animals. Graphic by A. Wilson; flying 

squirrel illustration by J. Perkins.

in species interactions in a changing environment, changes in population demography with population density, identities of individual 

species, and environmental variation are as important determinants 

of population and community dynamics as are the number of levels 

in a food chain, or the position of the system along a resource gradient. The effects of ecological factors can cascade up or down in the 

trophic system; thus flow of interactions is as important as flow of 

energy (Hunter and Price 1992). For example, shrubs provide food 

and cover to squirrels. Marked differences in ability of shrub abundance alone to explain variance in squirrel activity among studies is 

due to differences among studies in (1) the degree to which shrubs 

of various kinds are lacking, (2) variances in shrub cover relative to 

variances in abundance of other habitat elements, and (3) complementarity between midstory, understory, and decadence. In other 

words, few wildlife-habitat relationships are based on simple linear 

relationships involving one or two habitat elements. As Billick and 

Case (1994) stated, “the dynamic behavior of the full community 

cannot be predicted based on observations of interactions between 

pairs of species.” Rather, almost always a complex of elements is involved, there is redundancy in some functions of some elements, and 

interactions with other species are important. Large differences in 

coarse woody debris (5 to 25 percent cover) and shrub abundance (0

to 95 percent prevalence) among stands on the Olympic Peninsula 

influence the structure of forest-floor small mammal communities 

and the abundances of various species of shrews, mice, and voles, 

but even small differences in plant species composition may be as 
Cavities Truffles Cones Understory Nighttime

Cavity abundance

Truffle abundance

Cone abundance

Understory density

Nocturnal activity

Northern flying squirrel

Townsend’s chipmunk

Douglas’ squirrel

324 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 68—Biocomplexity creates 

more niche dimensions, which allows 

different species to coexist together. 

Blue words represent the X-axes; 

Brown words represent the Y-axes. 

Graphic by A. Wilson; Photos courtesy of USDA Forest Service.

important (Carey and Harrington 2001, Carey and Johnson 1995). 

Dimensions of potential habitat spaces (usually expressed as statistical distributions of habitat elements) determine not only habitats 

realized within a given space but also which factors explain the most 

variance in animal activity in that space. It is generally accepted 

that factors limiting populations differ among locales and seasons 

(Fretwell 1972).

Spatial-Scale & Spatiotemporal Heterogeneity

In the ecology of fungi, vascular plants, invertebrates, and vertebrates, many ecological processes take place at a physical scale of 

less than 50 square meters, the level of individual organisms (the 

death and decay of a tree), structural features (fruiting of an ectomycorrhizal fungus in a decayed log), and the neighborhood of a 

dominant tree. The four structuring processes of forest biotic communities (crown-class differentiation, decadence, stratification, and 

understory development) take place at varying small scales—the 

first two at the level of individual trees and the last two at the level 
C H A P T E R 7 From Ecology to Forest Management 325

of small patches (0.01 to 1.0 hectare). The interactions among these 

processes that develop habitat breadth, however, are exemplified at 

scales of 0.1 to 0.5 hectare over areas of 10 to 100 hectares, account 

for two-thirds of the variance in vegetation structure across biotic 

communities, and can be used to differentiate realized habitat (actually occupied) from potential habitat (the total multivariate habitat 

space available) of organisms of intermediate mobility (small amphibians, birds, and mammals) with an accuracy of about 65 percent 

within biotic communities. But the four structural processes explain 

less than one-fifth of the variance in animal activity within biotic 

communities. For example, squirrels do not select any small subset 

of vegetation site types for their activities; their foraging patches 

and home ranges may differ little, on average, from the larger biotic 

communities in which they occur. Differences lie in the proportion 

of the area of the biotic community used, the size of foraging patches, the size of home ranges, and the densities of the populations 

(Carey et al. 1999b) (fig. 69). Amount of area used generally tends 

to increase with body size of mammals: red-backed voles tend to be 

more restricted in their movements than deer mice, and deer mice 

are more restricted than eastern gray squirrels (Carey 1981). Still, 

within a group of similar size, home ranges can differ markedly—

the Douglas’ squirrel is much localized in its movements (tens of 

meters), the flying squirrel may travel a kilometer or more in a night, 

over several hectares (Carey 2000a) (fig. 70). Predators, of course, 

tend to have larger body sizes and substantially larger home ranges 

than their prey. Pairs of spotted owls have home ranges spread over 

500 to 3,000 square kilometers and larger depending on level of 

forest fragmentation, prey base, and physiographic province (Carey 

et al. 1992).

Processes taking place at scales of 1 to 100 hectares, the level of 

populations (demographic processes) and biotic communities (selforganization of the community), include, for example, competitive 

exclusion, development of species richness in a plant community, 

predator-prey interactions, and postinteractive niche separation 

(multivariate community spaces actually occupied by species population in the presence of other species). Habitat selection of wideranging vertebrates and dispersal and colonization processes of many 

species take place at the scale of 100 to 10,000-hectare landscapes, 

or even larger. Models that incorporate both demographic and environmental factors suggest that genetic diversity and divergence in 

populations is most affected by the proportion of biotic communities 

in the landscape that are occupied (as affected by disturbance frequency) and the density of individuals within the communities as 
326 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 69—Differences in home 

range size: (A) Movement patterns of 

three northern flying squirrels on an 

approximately 0.5-square kilometer 

plot of 300-year-old trees—the darker 

the background color, the higher the 

density of large conifers; (B) areas used 

by a northern spotted owl across about 

4.0 square kilometers of forest during 

the nonbreeding season (adapted from 

Carey et al. 1999b and Carey and 

Peeler 1995). Graphic by A. Wilson.

~0.5 km

Adult male

Adult female

Juvenile

Increase in 

large-conifer 

density

~4.0 km

Constant

Intermittent

Sporadic

Used but not selected

Nonbreeding use pattern

A

B
C H A P T E R 7 From Ecology to Forest Management 327

determined by habitat quality (Gibbs 2001). This is a key point in 

landscape design—avoidance of environmental conditions and 

community structure that leads to depauperate communities (low 

proportions of communities occupied for many species), with poorquality habitat for many species that do inhabit them, and that also 

reduce permeability of the landscape to dispersal. However, highly 

subdivided local populations suffering frequent local extinction may 

retain more diversity than less subdivided populations of equivalent 

size (Ray 2001), suggesting that shifting-steady state mosaics, with 

a low-to-moderate proportion of the landscape in reorganizing and 

early-seral states may provide many opportunities for maintaining 

genetic diversity and maximizing adaptiveness. This, in essence, is 

part of the creative destruction hypothesis of Holling’s Panarchy 

theory. Thus, understanding how scale interacts with habitat quality 

is important to AIM for conservation of genetic diversity (table 29). 

Across biotic communities in the landscape, various habitat 

dimensions exhibit high correlations (r > 0.50) with one another. 

That communities may differ in horizontal heterogeneity and vertical heterogeneity is apparent; heterogeneity, habitat space, and habitat breadth generally increase with time since catastrophic disturbance—but with niche-diversification communities having extreme 

values for some elements (e.g., snags and fallen trees). Structuring 

processes and habitat breadth explain more among-community 

variance in squirrel activity than individual habitat elements and 

provide better models of squirrel activity than even classification of 

communities into seral stages. Processes explain up to 75 percent of 

squirrel activity and squirrel carrying capacity. Managed forests in 

competitive exclusion, in general, have less developed niche space 

and coarser grain than forests in niche diversification and oldgrowth forests. Grain in old growth was less than the height of an 

old-growth tree (around 70 meters); that is, 50 meters for shrub 

patches, 25 meters for midstory development, and 80 meters for areas of closed canopy (Carey et al. 1999b). Small gaps (loss of one to 

three dominant trees) at high frequencies across old growth and low 

sun angles produce fine-scale heterogeneity with close juxtaposition 

of habitat elements (snags, fallen trees, patches of shrubs, patches of 

midstory, patches of herbaceous cover, patches of open forest floor) 

and different species and life forms. In response to increased heterogeneity on a fine scale, foraging patches and home ranges overlap 

more and total activity increases. Thus, accumulation of processes 

in late-seral, natural stands results in an emergent property of niche 

diversification that provides more stable habitat for squirrels; carrying capacities for squirrels have maximum values in old growth. 
360’

160’

American football field = 

~ 1⁄2 Hectare 

1,800 ft2

Garden

~1-acre plot

270’

328 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 70—Visualizing acres 

and hectares: There are 2.5 acres in 1

hectare. An American football field is 

approximately a half hectare in size. A 

1-acre house plot fills approximately 

75 percent of a football field. Thus, a 

squirrel moves across a good part of a 

suburban neighborhood in one night. 

Graphic by A. Wilson.

Nevertheless, individual communities deviate significantly from average conditions within their nominal seral stages in their capacity to 

support squirrels and in various measures of habitat space. As Carey 

(1995) reported for the Olympic Peninsula, nominal seral stage may 

not always be a good predictor of habitat quality. Structuring processes, habitat breadth, and site moisture provide better descriptions 

of ecosystem development and niche diversification than nominal 

seral stage. Given process-based community development, AIM has 

the potential to accelerate niche diversification. 

The role of spatial scale can be illustrated by the ecology of fishers in south-central British Columbia (Weir and Harestad 2003), 

goshawks in the Southwestern United States (Reynolds et al. 1992), 

and spotted owls in the Pacific Northwest (Carey 1985b, 1993; Carey 

et al. 1992, 1999b; Carey and Peeler 1995; Carey et al. 1990). Weir and 

Harestad (2003) described spatial scales as habitat elements within 

patches within biotic communities within home ranges within landscapes within the geographic range of the species. Fishers avoided 

areas without overhead (overstory or shrub) cover. The fishers selected areas for foraging at the biotic community and patch scales on 
Table 29—The scales and attributes of ecosystems

Structure Composition Processes

Regional  Major landform features  Regional species pool  Climate, weather, and 

geologic events

Landscape  Landscape patterns and 

dynamics

 Landscape elements  Disturbance regimes

Biotic community  Relative abundance of life 

forms, functional groups, 

and species

 Species, genotypes, and 

ecotypes

 Development, mutualism, 

synergy, competition, and 

predation

Population  Age structure and sex ratio  Genetic diversity  Colonization, birth, death, 

and dispersal

Source: Adapted from Noss 1.

C H A P T E R 7 From Ecology to Forest Management 329

the basis of coarse woody debris, foliage height diversity, and shrub 

cover; in other words, a complex forest floor provided the primary 

foraging areas for fishers. However, an overly complex forest floor 

(more than 80 percent shrub cover), may reduce the likelihood of 

capturing prey, and dense canopies intercept snow, leaving the forest floor more open. Fishers selected particular habitat elements for 

resting and denning, such as mistletoe brooms in spruce and cavities 

in deciduous trees, respectively. American marten exhibited similar 

selectivity in Ontario (Fryxell et al. 1999).

Goshawks exhibit selectivity at multiple spatial scales in the Pacific Northwest (Finn et al. 2002), interior Northwest (HanauskaBrown and Bechard 2003), and Southwestern United States (Drennan and Beier 2003, Reynolds et al. 1992). The northern goshawk 

breeds in coniferous, deciduous, and mixed forest in North America 

(Reynolds et al. 1992). It uses various forest types, ages, structural conditions, and seral stages. The goshawk preys on small birds 

and mammals including robins, grouse, squirrels, and hares. In the 

Southwest, it is found in ponderosa pine, mixed species, and sprucefir forests but has been declining in response to timber harvest, fire 

suppression, and grazing. Reynolds et al. (1992) developed management recommendations for goshawks based on several tenets: (1) 

goshawks and their prey are limited by their food and habitat; (2) 

abundant prey reduces the probability of food limitation on goshawks; (3) a wide variety of prey is less likely to result in goshawk 

population fluctuations than one or two prey species; and (4) active, 

intentional management for goshawks can sustain goshawk habitat. They concluded that past management had produced thickets of 

small trees prone to fire, insects, and diseases and will require disturbance before developing further. They also recognized that forest 
330 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

reorganization, growth, and development differ with location and 

that no single management prescription is likely to be appropriate 

for all sites. Large live trees, snags, and fallen trees, however, are 

important elements of the habitat of a variety of plants and animals 

and every hectare should contain several. A landscape most suitable 

to goshawk persistence would be one of an interspersed mosaic of 

developmental stages. 

Goshawk habitat requirements include two to four nest patches 

(around 12 hectares) of large old trees with dense canopy cover. A 

family area of 170 hectares around a nest patch consisting of a variety of forest types and conditions is necessary for fledglings to hide 

in (patches of dense trees) and to learn hunting techniques (patches 

of herbaceous and shrubby understory mixed with small openings, 

snags, and logs). A larger foraging area of around 2,200 hectares is 

needed. This latter area is best characterized by large trees, relatively 

open understories, with small (0.1 to 0.8 hectare) to medium (0.8 to 

1.5 hectare) openings (with a maximum width of 40 to 60 meters), 

with dense patches of thickets scattered throughout; the majority 

should be mid-aged to old forest (Reynolds et al. 1992). Active, intentional management techniques include long (200- to 300-year) 

rotations, legacy retention with live legacy trees in groups of 3 to 

6 with 2 to 5 groups per hectare, 5 to 7 snags per hectare, 7 to 12

fallen trees per hectare, and 12 to 35 megagrams of coarse woody 

debris per hectare; thinning from below with non-uniform spacing, 

minimizing road density and permanent skid trails; and prescribed 

burning to reduce fuels. Projected benefits beyond those to goshawks include improved landscape function, habitat for old-growth 

species, reduced susceptibility to catastrophic disturbance, increased 

forest productivity, enriched mycorrhizal communities, forest products, and forage production.

Spotted owls selectively use old forest out of proportion to its 

occurrence in mosaic landscapes, and concentrations of old forests 

result in smaller home ranges and more stable social structures (Carey et al. 1992, Carey and Peeler 1995, Carey et al. 1990). Selection 

for complex forests and forest floors for foraging is related to prey 

abundance and opportunities to catch prey for spotted owls in the 

Pacific Northwest (Carey et al. 1992, 1999b); but as old forests are 

fragmented, prey may be depleted temporarily by owl predation, and 

owls may switch to younger forests, especially younger complex forests, where prey may be temporarily higher than in the exploited old 

growth. Thus, at the landscape level, replacement of late-seral forest by ecosystem-reorganization and competitive-exclusion stages 

has negative effects on spotted owls (Carey and Peeler 1995). These 
C H A P T E R 7 From Ecology to Forest Management 331

managed forests are avoided or used rarely, although, where duskyfooted woodrats are abundant, owls may forage along forest-­clearcut 

edges (Diller and Thome 1999, Giusti 1999, Solis and Gutierrez 

1990, Ward et al. 1998) and in early-seral stages (Carey et al. 1992). 

But managed and natural forests more advanced in development 

(understory reinitiation and niche diversification) may be around 25

percent of the areas regularly used by spotted owls for roosting and 

foraging. The biomass of squirrels (Douglas’ squirrel, northern flying 

squirrel, and Townsend’s chipmunk) increases with forest development (Carey 1995). The size of all three squirrels makes them especially attractive to predators common in Pacific Northwest forests, 

such as hawks, owls, and weasels. The squirrels are near the maximum size limit for many of these predators. Abundances of chipmunks, flying squirrels, and Douglas’ squirrels increase with forest 

development despite overlap in their diets, den site use, and space 

use (Carey 1991, 1995; Carey et al. 1999b, 1997). The squirrels seem 

limited by variability in food abundance and dens but not interspecific competition in complex environments. Late stages of forest 

development provide habitat structure that mediates predation and 

variety in fruit production that offsets high variability in availability 

of individual food items. The resulting increased prey biomass attracts and supports predators.

C H A P T E R 8

AIM for Resilient Forests

Active, intentional management for resilient, biologically complex 

forests has the purpose of maintaining forested ecosystems and 

landscapes that first and foremost are capable of adapting to changing environmental conditions, including global climate change. 

Managing for resiliency is the first obligation for intergenerational 

equity. Managing for biocomplexity serves the purpose of maintaining biological diversity and the diverse values contemporary society 

desires from its forests, including broad values of environmental 

sustainability, social civility and equity, and economic activity. These 

values are diverse: clean air and carbon sequestration; clean water 

with modulated flows; open, green space; aesthetic, natural places 

for recreation and spiritual renewal; complete biotic communities of 

plants, fungi, invertebrates, and vertebrates; healthy soils with minimal erosion; abundant populations of various species of wildlife and 

fish; provision for subsistence hunting, fishing, and gathering guaranteed to Native Americans as obligated by treaties; opportunities 

for hunting, fishing, and gathering by other people; opportunities for 

wildlife viewing and nature study; sustainable flows of wood products that allow society to meet its needs domestically from environmentally beneficial forestry without contributing to degradation of 

the environment in less-developed countries and that contributes to 
334 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 60—The Seven 

Stages of Ecosystem Management (Brussard et al. 1998)—Ecosystem management is managing 

areas at various scales in such a 

way that ecosystem services and 

biological resources are preserved 

while appropriate human uses 

and options for livelihood are 

sustained. The stages of ecosystem 

management are:

 Delineate the system to be 

managed.

 Define strategic goals [degree 

of intentionality].

 Develop a comprehensive understanding of the ecosystem.

 Analyze the socioeconomic 

contexts.

 Link the socioeconomic and 

ecological understandings in a 

heuristic model.

 Implement experimental management actions.

 Monitor results, assess longterm success or failure, and 

apply learning to the next 

management action.

domestic economic activity and the support of rural communities; 

sustainable flows of commercial nontimber products such as mushrooms, floral greens, and other natural products; and revenues to 

landowners be they federal, state, trusts, corporate, or nonindustrial, 

small, private landowners. This is a tall order.

Management can be passive (the choice is made not to intervene in any way except to reduce or exclude human activities), reactive (responding only to threats or emergencies), or active (deliberate actions are taken). Passive management includes designation of 

reserves, such as research natural areas, wildernesses, national parks, 

late-successional reserves, and areas devoted to particular species. 

The Nature Conservancy has a long history of success in establishing reserves of especially valuable (aesthectically, scientifically, biologically, and rare in the landscape) ecosystems. Some actions, such 

as fire threat reduction and restoration activities, may be appropriate 

in some of these reserves. Passive and reactive management contribute to achieving some of the goals of AIM (including some that 

cannot be achieved with active management, such as protection of 

old-growth forests) but cannot fully achieve AIM for multiple values. Active management of forests occurs anytime silvicultural practices are implemented, even when the stated intent is management 

for one or a narrow set of particular products, species, or structures 

rather than management of processes. This, of course, is not the same 

as AIM for resilient, complex forests that are valued by people for diverse reasons. This difference between common active management 

and AIM is in intent. Active, intentional managemant can be evaluated by using the concept of intentionality—the degree to which all 

information (social, economic, and ecological) has been considered 

in determining how to manage ecological processes for sustainability 

of complex social, economic, and ecological systems (that is, what 

the manager thinks about in deciding “what to chop”). Thus, AIM, 

and other less-developed forms of ecosystem management (Brussard et al. 1998, Grumbine 1994) (sidenotes 60, 61), are significant 

in that they focus on whole systems (AIM addresses holarchies), not 

some few parts of a system; they include public involvement in goal 

setting (AIM extends that to on-the-ground collaborative management and monitoring); they integrate conservation into economic 

activity (AIM includes noncommodity instrumental values and aesthetic-spiritual values as well); and they shift from a paradigm of 

linear comprehensive management to cyclic-incremental or adaptive management (AIM extends this shift to nonlinear thinking and 

managing for system adaptiveness). Ecosystem management has as 

its overriding goal to “ensure that ecological services and biological 
C H A P T E R 8 AIM for Resilient Forests 335

Sidenote 61—What is ecosystem management? (Grumbine 

1994)—Ecosystem management is 

integration of scientific knowledge of ecological relationships 

within a complex sociopolitical 

and values framework toward 

the general goal of protecting 

ecosystem integrity, including the 

protection and maintenance of:

 Natural ecosystem types (biotic communities)

 The diversity of native species

 Ecosystem health and integrity

 Ecosystem processes

 Ecosystem services

 Human economies based on 

ecological principles

 Sustainable production of 

ecosystem products

Sidenote 62—“Viable” systems (Brussard et al. 1998): 

 Currently provide expected 

goods and services with reasonable efficiency

 Have present uses that are not 

disrupting processes, which 

generate and maintain the 

desired composition, structure, 

and function of the ecosystem 

or its future potential

 Have a present use and current 

condition that does not degrade areas beyond the systems 

borders

 Have the capacity for selfmaintenance and self-regeneration after moderate external 

stresses or perturbations

resources do not erode irreversibly as a result of human activities;” 

sustainable ecosystem management maintains or enhances current 

utility, future potential, containment, and resilience (Brussard et al. 

1998) (sidenote 62). On the other hand, AIM seeks to integrate values 

for ecological services and biological diversity into the very thought 

processes underlying management. Active, intentional management 

attempts to integrate applied sciences—forestry, wildlife management, range management, recreation management, epidemiology, 

integrated pest management, fire threat reduction, transportation 

system management, and forest engineering. Also, AIM emphasizes 

maintaining a high diversity of species, keystone complexes, ecosystem function, and ecosystem adaptability to changing environmental conditions. There are well-documented (1) patterns of commonness and rarity of known species—most are rare (Preston 1948, 1960, 

1962a, 1962b, 1969, 1980, 1981); (2) significant roles of randomness 

and stochasticity in influencing species occurrences (Hubbell 2001); 

(3) substantial ignorance of most species (most have yet to be described); and (4) inevitable change in ecosystems (sidenote 63) and 

the composition of their biotic communities through time and space, 

all of which owing to the increasing stress from increasing human 

populations, species invasions, global climate change, surprises, and 

shifts among alternative stable states (Gunderson and Holling 2002, 

Johnson and Mayeux 1992, Paine et al. 1998, Tausch et al. 1993). 

Active, intentional management does not pretend to maintain all 

species in every place where they once occurred or where they could 

potentially occur under extant conditions. It does seek to conserve 

biological diversity and recognizes the special values of keystone, 

flagship, relict, aesthetic, and charismatic species, species diversity, 

and functional group diversity to ecosystem stability (table 30) and 

productivity, conservation of nature, and to people; thus, AIM focuses on reality and empiricism when setting goals. For example, species dominance, and even membership, of functional groups might 

change, but the ecological function may be retained; reduction of 

the diversity within functional groups, then, may result in loss of 

system adaptiveness. Active, intentional management seeks to control the introduction of, and to remove, introduced and damaging 

exotic species but also recognizes species introductions will occur 

no matter what steps are taken and that not all introduced species 

will result in significant impairment of ecosystem function or loss of 

native diversity. And not all introductions of damaging species, from 

whatever source, will be reversible, even with substantial effort. Thus, 

AIM focuses as much as possible on (1) management of processes to 

maintain native diversity and maximize resilience and adaptiveness; 
336 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 63—Ecosystem 

stability and the balance of nature 

according to Johnson and Mayeux 

(1992):

 Common assumptions about 

ecosystem stability and a 

delicate balance of nature are 

unwarranted paleoecologically, biochronologically, and 

biogeographically.

 Species have been added and 

removed without greatly affecting ecosystem function.

 Natural ecosystems exhibit 

greater stability (inertia) in 

physiognomic structure and 

functional processes than in 

species composition.

 Some ecosystems persist in 

unstable rather than stable 

states.

And according to Tausch et al. 

(1993):

 There is no natural vegetation 

(equilibrium condition); plant 

communities differ in space 

and time.

 No area is without some human impact.

 No management is impossible given human impacts and 

exotic invasions.

(2) use of developmental pathways and trajectories to predict and 

manage for future conditions; and (3) use of baselines, benchmarks, 

and monitoring of carefully selected groups of species to judge failure, progress, and success (table 31). Active, intentional management 

strives to integrate individual, social, economic, and environmental values into a coherent whole that is normative in determining 

which human demands and management practices are appropriate 

in managing the interactions of individuals, human communities, 

and biotic communities. Key fundamental values for AIM for general 

sustainability include intragenerational, transnational, and intergenerational equity. Intentional management requires broad participation by stakeholders and a new, sophisticated role for scientists as (1) 

science interpreters; (2) decentered participant-facilitators of issue 

formulation, debate, and issue resolution; (3) modelers and testers of 

resolutions; and (4) participant-facilitators in group learning (sidenote 64). Good AIM requires separating the wheat from the chaff in 

collaborative experimental learning processes, embracing ambiguity, 

uncertainty, and change, and proceeding with the highest intentions 

and most decentered views.

Components

A dozen or more on-the-ground tactics are used in AIM strategies 

for biodiversity, biocomplexity, resilience, and general sustainability. 

Legacy Retention

Active, intentional management extends the concepts of green-tree 

retention, snag retention, structural retention, and variable-retention 

harvest systems to retention and maintenance of both biological and 

geological legacies during every step of active management. In managed forests, variable-retention harvesting is often the catastrophic 

disturbance/creative destruction event/reorganizing force that sets 

the stage and determines the species retained onsite to reorganize 

into a new community. Legacy retention should be integrated with 

protection of rock outcrops, talus slopes, balds, meadows, seeps, 

springs, wetlands, headwater streams, colluvial soil, areas of deepseated landslides, areas of shallow-rapid landslides, streamsides, riversides, and areas of excessively poor potential for growth of trees. 

These geological features form a template for the retention of intact 

patches of forest (clumped and linear legacy retention) and form the 
Table 30—Characteristics of ecosystem stability and resilience that can be used predictively or in monitoring

Characteristic Definition Example

Inertia  Resistance to change in structure, function, 

or trajectory of development

 A gap-phase complex-forest mosaic is unaffected by low to moderate tree mortality 

because trees regenerate and grow; even gaps 

of 5 to 7 trees can be assimilated. A conifer forest with poor height : diameter ratio 

has little inertia in the face of wind, ice, or 

snowstorms; older ponderosa pine parklands 

are little affected by low- to moderate-severity 

surface fires.

Elasticity  Rapidity or time of restoration of structure, 

function, and trajectory of development

 Older closed-canopy Douglas-fir monocultures may have less elasticity than a multispecies multitolerance complex; a multispecies 

complex may require 120 years to develop 

from reoganization to niche diversification; 

fire-prone lodgepole pine forests recover 

rapidly from crown fires owing to serotinous 

cones.

Amplitude  Brittleness, or range of disturbances from 

which the system can recover structure, 

function, and trajectory

 Complex forests in landscapes of complex forests may recover from minor to catastrophic 

disturbance; simplified forests may not recover 

complex structure and function from even 

patch-level disturbances such as root rot; with 

prolonged fire exclusion, many forest types 

may not recover after a catastrophic disturbance.

Hysteresis  Degree to which restoration is an exact 

reversal of the path of degradation, more 

relevant to chronic than acute disturbance

 After disturbance, do the last species to die 

return first, or are they last in a succession of 

species? What happens when livestock are 

removed from a range?

Malleability  Ease of permanent alteration; degree to 

which the recovered system differs from 

the original system prior to disturbance

 Depending on disturbance regime, a complex 

forest may return along a continuum from a 

complex state of high biotic integrity to a species-poor, simplified alternative stable state.

Source: Adapted from Westman 1978.

C H A P T E R 8 AIM for Resilient Forests 337

first basis of a landscape mosaic. The degree of retention of biological legacies outside these patches then differs inversely with rotation 

age of forests (time between major harvests that result in ecosystem 

reorganization) and size of harvest units: the shorter the rotation 

age, the greater the legacy retention in variable-retention harvest 

systems; the larger the harvest unit, the greater the retention. Both 

Washington and Oregon (and many other states) have minimum 

guidelines for retention outside of the geologic areas. The goal of 

AIM is to maintain a biologically-complex forest over the landscape 
338 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 64—Roles of 

scientists, technologists, and land 

managers in collaborative management:

 Scientists are often (1) historians of the development of new 

knowledge and new practices; 

(2) philosophers, relating 

science to different values 

(Ph. D. is doctor of philosophy—the study of the nature 

and principles of knowledge, 

truth, existence, and moral and 

aesthetic values); (3) technical 

or technological experts and 

advisors; (4) informed public 

citizens; and (5) critical thinkers.

 Technical specialists play different roles—they (1) help to 

set organizational priorities 

and management standards; 

(2) compile specific local 

information on environmental 

variables, populations, and 

habitat relationships; and (3) 

make measurement and collect 

data.

 Land managers often (1) know 

the history of specific pieces 

of land—its characteristics, 

use and utility, and response 

to management; (2) have 

conducted case history experiments; (3) serve as implementers of management decisions; 

(4) may offer a particular land 

ethic; and (5) may be knowledgeable about economic, 

agronomic, and ecologic 

productivity.

and each site, biotope, and ecosystem within the landscape. In western Washington, conservation of biodiversity seems to be possible if 

less than 15 percent of the landscape is in early-seral stages of forest 

development in any decade and about 15 percent of each variableretention harvest unit is retained as forest. Actual retention, however, must be determined in major part by the combination of geologic 

influences on retention and effects of rotation age and harvest unit 

size on reducing forest influence at the level of site and landscape.

During intermediate treatments (precommercial and commercial thinnings), legacies should be identified, protected, and 

enhanced. Skips in thinnings can be used to protect ecologically 

important features such as cavity trees, moderately decayed snags, 

small wetlands, intact patches of forest floor, and legacies left during 

the preceding reorganizing disturbance (such as intact patches of 

older forest). Large fallen trees can be protected and even sometimes 

moved and replaced to facilitate movement of equipment. Gaps can 

be used to favor growth of selected trees like bigleaf maple or madrone, promote epicormic branching on legacy trees, and release advanced shade-tolerant regeneration.

Multispecies Management

At each step of active management from variable-retention harvests 

to planting to precommercial and commercial thinning, care is taken to ensure multiple site-appropriate trees species are maintained. 

Two or more species of conifers and two or more species of deciduous trees are desirable for numerous ecological and economic reasons, but not, of course, in equal abundance. Beyond trees, in making 

decisions about what to manipulate, attention is paid to promoting 

a variety of tall shrubs as well. The relative abundances of species to 

be promoted differ with site, potential natural vegetation classifications, predictions about what might happen to plant communities 

with climate change, management of decadence (e.g., maintaining 

deciduous trees that might become cavity trees and conifers, like 

grand fir, that have high potential to form hollow trees), and opportunities for diversification of wood products in terms of species 

(e.g., Douglas-fir, western redcedar, and red alder all have different 

markets) (figs. 71, 72). 
C H A P T E R 8 AIM for Resilient Forests 339

SAVE Trees and Shrubs

Over 50 species of trees and shrubs in the Pacific Northwest have 

special attributes that are valuable ecologically (SAVE). These SAVE

trees exist in almost all forest (see, e.g., Carey and Gill 1980 and 

Carey and Healy 1981 for Appalachian forests). Wilson and Carey 

(N.d.) provide a list of these for the Pacific Northwest (table 32) and 

guidance on marking for retention during precommercial and commercial thinning and variable-retention harvesting. A few of these 

go a long way. If absent, seeding and underplanting some of these 

may be appropriate.

Planting, Underplanting, and Seeding

Planting is used to recover a forested condition quickly and to ensure some minimum level of tree species diversity and density. Substantial natural regeneration usually accompanies planting. When 

management or lack of management has resulted in closed-canopy 

monocultures, underplanting and seeding can be useful tools to restore lost diversity of trees and shrubs, particularly tall shrubs, deciduous trees, and shade-tolerant trees, depending on site and region.

Precommercial Thinning

After legacy retention, precommercial thinning provides the next 

most important intervention to ensure that biological diversity is 

promoted instead of discouraged and to set the stage for the finescale mosaic that will characterize the developing ecosystem. Of 

course, legacy maintenance is an important factor in precommercial 

thinning. But the main features of precommercial thinning are (1) 

maintenance of tree and shrub diversity, (2) promotion of crownclass differentiation, (3) promotion of rapid growth, and (4) opportunities to develop isolated dominant trees with deep crowns that 

provide shelter and foraging normally found only in older trees. Although empirical guidance is lacking, precommercial thinning offers 

opportunities for experimenting with spatial pattern to produce biocomplexity. Clumps of deciduous trees could be maintained. Shadeintolerant trees can be alternated with shade-tolerant trees to hasten 

crown-class differentiation and, in time, canopy stratification. Providing growing space to individual deciduous trees like red alder 

and black cottonwood can lead eventually to cavity tree formation 
Table 31—Prediction and description of stability and resilience

Index Inertia Recovery

1  Adaptation of indigenous 

species to environmental 

fluctuation

 Proximity of recolonization sources and landscape 

permeability

2  Degree of functional 

redundancy

 Mobility of propagules 

and biological legacy 

retention

3  Cleansing capacity for pollutants

 Physiochemical suitability 

of site for recolonizaton

4  Chemical and biomass 

accumulation buffering

 Biocomplexity and niche 

diversification

5  Proximity of key variables 

to change thresholds

 Toxicity of site, presence of 

ruderal, and exotic species

6  Degree of management 

efficacy

 Degree of management 

efficacy

Source: Adapted from Cairns and Dickson 1977 and Cairns 1986.

340 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

during periods of community development in which few cavities 

are being formed in conifers. Providing growing space to individual 

bigleaf maple enhances numerous aspects of biocomplexity.

Commercial Thinning

Heretofore, considerable discussion has been devoted to the benefits 

of commercial variable-density thinning, and it will not be repeated 

here. But it is important to recognize, that commercial thinning offers the same opportunities as precommercial thinning to ensure 

tree and shrub diversity, implement SAVE tree guidelines, and protect legacies. In addition, commercial entries also provide the resources for decadence management—stimulating the development 

of cavity trees and augmenting coarse woody debris on the forest 

floor—and underplanting and seeding to restore missing elements 

of diversity. Thus, thinning also can be used to mitigate effects of 

past mismanagement and to restore forest health, including increasing resistance to wind and snow damage, reducing susceptibility to 

crowding, moisture stress, and insect attack, mitigating the effects 

of dense monocultures on development and spread of root disease, 

and reducing risk of catastrophic fire. As in all aspects of AIM for resilience, the situations will always be complex and will require sitespecific analyses as well as landscape- and regional-scale analysis 

and planning. In addition to decadence management,underplanting, 
C H A P T E R 8 AIM for Resilient Forests 341

Figure 71—Second-growth 

clumped legacy retention with hardwoods in an industrial forest. Photo by 

A. Carey.

and seeding, prescribed fire at times can be a useful adjunct in commercial thinning. In almost all cases, inducing heterogeneity at a 

fine sale (0.2 to 1 hectare) will be appropriate and help contribute 

to achieving biocomplexity, increasing resilience, and mitigating the 

forest health risks resulting from poor past management.

Decadence Management

Decadence management includes retaining coarse woody debris on 

the ground throughout a major harvest area. Covers of more than 10

percent in dry-mesic Douglas-fir forest and more than 15 percent in 

mesic-hydric western hemlock forests seem reasonable targets. The 

smaller the diameters left and the closer the values are to 10 percent 

and 15 percent, the sooner the coarse woody debris will need to be 

augmented. Provision should be made for cavity trees during major 

harvests. These could include well- to moderately-decayed conifers more than 80 centimeters in diameter at breast height (d.b.h.), 
342 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Figure 72—Mixed hardwoodconifer legacy retention along streams 

and seeps in an industrial forest. Photo 

by A. Carey.

lightly- to moderately-decayed trees more than 80 centimeters in

d.b.h., live trees more than 50 centimeters in d.b.h. but with evidence of past damage to the top and a reiterated top; live trees more 

than 50 centimeters in d.b.h. that are sound can be left, topped above 

two to three whorls of live branches, and branches perpendicular to 

prevailing wind direction can be lopped to reduce wind resistance. 

The shorter and more decayed the trees are, the shorter time they 

will serve as a cavity tree. A well-decayed, short (greater than 5 meters), large snag may be used for nesting only occasionally by small 

secondary cavity-using birds or small mammals. Large lightly- to 

moderately-decayed live trees and dead trees will be used for nesting, roosting, perching, and denning often, and simultaneously, by 

a variety of cavity-using birds and mammals. Retaining deciduous 

trees to allow them to grow and later be overtopped and become 

snags (red alder) or to be maintained indefinitely and develop cavities while still alive (madrone and bigleaf maple) is an important 

aspect of decadence management. 

During thinnings, trees with cavities or with high potential for 

cavities can be marked for retention. Some dominant live trees can 

be wounded (cavities excavated, lightning scars simulated, and crevices incised with a chainsaw—to more quickly provide cavities and 

crevices to wildlife and to provide the proximal cues to wildlife that 

such a tree may have cavities and crevices), topped, and released to 

promote continued height growth, allow a new crown to develop, 

accelerate development of epicormic branches, and initiate decay 

processes that can continue for decades to centuries. Some damage 

will be caused by the felling of trees and contribute to the decadence 
C H A P T E R 8 AIM for Resilient Forests 343

processes; second and third thinnings in older stands are more likely to promote decadence in some retained dominants. Inoculation 

with decay-causing fungi also works in some systems, and artificial 

cavity and nest structures can be used to promote early colonization 

of young forests by cavity-nesters and to benefit threatened species 

(Bellrose et al. 1964; Bull 1991; Bull et al. 1997, 1981; Carey 2002b; 

Carey and Gill 1983; Carey and Sanderson 1981; Carey et al. 1999d; 

Copeyon et al. 1991; Lewis 1998; McArdle et al. 1961; McComb and 

Noble 1981a, 1981b, 1981c; Parks et al. 1999). If, because of past management, coarse woody debris is sparse, some felled trees can be left 

to contribute to maintaining the 10 percent and 15 percent levels; 

if large fallen trees are absent, smaller trees can be aligned longitudinally and stacked as pyramidally to form coarse woody debris 

structures with large size and high surface area to promote high 

biological activity.

Rotation Age and Uneven-Age Management

The longevity of Pacific Northwest conifers allows more flexibility 

in management than in many other forest types. Many of the techniques presented here can be used in restoration efforts to direct 

second-growth forests to trajectories that will eventually produce 

old forests with the biocomplexity of present-day old growth; active 

management may cease after 1 to 10 decades. Douglas-fir/western 

hemlock/western redcedar forests, redwood forests, and some other 

types can be actively managed indefinitely (more than 500 to 1,000

years) without the need for “creative destruction” or an event that 

leads to fundamental reorganization of the biotic community. Douglas-fir dominated forests can be thinned multiple times with gradual 

replacement with shade-tolerant trees; at some point, no more dominant Douglas-fir will be taken, a significant Douglas-fir presence can 

be maintained, and continuous removal and autogenic replacement 

of shade-tolerants can occur. Uneven-age management systems can 

be used, but regeneration of Douglas-fir may require group-selection harvests that are essentially small patch cuts around 1 hectare. 

Uneven-age management can be used in hemlock-cedar forests. At 

the other end of AIM for multiple values, variable-retention harvests 

on alternating 70- to 80-year and 130- to 150-year intervals (with no 

major harvests on unstable slopes, next to streams, and other areas of 

special value) can be combined with multiple variable-density thinnings to produce robust, resilient forests in landscapes dominated by 

late-seral complex forest with high capacity for biological diversity, 
Table 32—Tree and shrub species of the Pacific Northwest with special attributes that are valuable ecologically

Conifers Broadleaf Shrubs

Douglas-fir 

Grand fir

Incense cedar 

Lodgepole pine

Mountain hemlock 

Pacific silver fir 

Pacific yew 

Ponderosa pine 

Sitka spruce 

Subalpine fir 

Western hemlock 

Western redcedar 

Western white pine 

Yellow-cedar 

Bigleaf maple 

Bitter cherry 

Black cottonwood 

Oregon ash 

Oregon white oak

Pacific dogwood

Pacific madrone

Paper birch 

Red alder 

Black hawthorn

California hazelnut 

Cascara

Devil’s club

Elderberry spp.

Evergreen huckleberry 

Huckleberry spp.

Indian plum 

Manzanita spp.

Oceanspray

Oregongrape spp.

Rosa spp.

Salal

Salmonberry

Saskatoon

Sitka alder

Sitka mountain ash

Snowberry spp.

Vine maple

Willow spp.

Source: Wilson and Carey [N.d.].

344 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

adaptation, and other environmental values while simultaneously 

contributing greatly to social and economic values. Severe ecological problems arise when rotation ages less than the above are used; 

rotation ages are prime determinants of cumulative effects in both 

space and time and determine, in large part, landscape character and 

potential for impacts on aquatic systems.

Landscape Management

Rotation age does much to determine the nature of the shifting, 

steady-state mosaic of AIM landscapes. However, the stage must 

be set before the play unfolds. Stage setting includes geologic and 

geomorphologic analysis at the watershed scale to identify unstable 

slopes, fragile soils, fragile biotic communities, riparian areas, reserves, 

special landscape elements, transportation systems (including public 

access management), and zoning for equipment use. Once the stage 

is set, then the condition of the various ecosystems in the landscape 

must be evaluated. Then the need for, and potential of, various AIM

strategies and techniques can be assessed and an AIM implementation plan developed. Care must be taken, however, not to make the 
C H A P T E R 8 AIM for Resilient Forests 345

Sidenote 65—Roles of scientists (Lach et al. 2003): 

 Reporting science results that 

others use in making decisions

 Reporting and interpreting science results for others 

involved in decisions

 Working closely with managers and others in integrating 

science results into management decisions

 Actively advocating for specific 

and preferred natural resources 

decisions

 Making decisions about natural resources management and 

policy

analysis and plan the driving goals; conservation of nature is the 

driving goal with environmental, social, and economic sustainability 

the ultimate goals. Care must be taken to avoid unnecessary zoning because zoning tremendously complicates efforts at restoration 

and sustainability (Carey et al. 1999c); the more constraints placed 

on the landscape, the less operational the landscape becomes. Care 

should be taken in formulating operating principles and instilling 

normative values for conducting on-the-ground operations for all 

involved from those setting specific objectives to those carrying out 

a narrow action on the ground. If longer rotations and good stage 

setting were used and the entire management group could come to 

consensus on a land ethic, much of present day zoning would be unnecessary in AIM landscapes. Similarly, collaborative management 

must be willing to accept short-term impacts and short-term risks 

to achieve long-term benefits and long-term risk reduction; overly 

zealous application of the precautionary principle often is a deliberate, conscious management decision to forego long-term increases 

in forest health and resilience to avoid short-term responsibility or 

controversy. If collaborative managers recognize their role as one of 

disturbance managers—to plan and implement disturbance to foster 

ecosystem and landscape resilience—some of the fear of short-term 

disturbance may be ameliorated (sidenotes 64, 65).

A question still being asked (but more rarely) in the Pacific 

Northwest is “Should old growth be actively managed?” Oldgrowth forests in the Pacific Northwest are unique, perishable, and 

irreplaceable (Carey 1998b). Old growth is a unique heterogeneous 

set of forests that developed under various unique sets of conditions 

over multiple physiographic and biogeograpic regions over various 

time periods ranging from 250 to over 1,000 years. In any one locale, 

old growth tends to be of the same approximate age (and can be 

defined by that age) and to have arisen from one or more large-scale 

fires and to have been affected by a subsequent series of intermediate-scale disturbances by fire, wind, and disease. All old growth 

shows evidence of small-scale disturbances owing to disease, wind, 

fire, and decadence that provide a variety of structures from snags to 

gaps. The various disturbances that originated and shaped the development of old-growth ecosystems produced forests of dimensions 

in terms of size of structures, biodiversity, complexity, and emergent 

properties that have not been matched in managed forests. Managers will never be able to recreate the disturbance histories and 

geographically extensive contexts under which today’s old-growth 

forests developed; thus, these forests are irreplaceable. Even though 

old-growth forests are quite stable compared to younger stands, 
346 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

Sidenote 67—Lessons 

from the Northwest Forest Plan 

(Haynes and Perez 2001): 

 A focus on individual species 

is necessary, but not sufficient.

 Elucidation of the key roles 

of species, species groups, and 

biotic communities is important to effective management.

 Providing for long-term evolutionary capacity is important.

 Intermittent streams are 

important in providing coarse 

woody debris and sediment to 

large streams.

 Legacies are important to 

aquatic communities.

 Collaborative adaptive management is necessary.

 Top down standards and 

guidelines do not work.

 Physiographic provinces differ 

in many ways.

 How timber is sold and contracted is as important as how 

much is sold.

 Communities differ.

 Nontimber forest products are 

important.

 Fungi are not old-growth 

dependent.

 Long rotations are good.

Sidenote 66—President 

Clinton’s five principles (Haynes 

and Perez 2001): 

 Never forget human and economic dimensions

 Protect the long-term health 

of forests, wildlife, and water

 Use science that is sound, ecologically credible, and legally 

responsible

 Produce predictable and 

sustainable flows of timber and 

nontimber forest products

 Insist on collaboration, not 

confrontation

they still are susceptible to catastrophic disturbance, for example, 

the old growth destroyed by the eruption of Mount St. Helens, tsunamis on the Washington coast, castastrophic windstorms on the 

Olympic Peninsula, and fire throughout the Pacific Northwest. In 

addition, the old Douglas-fir that characterizes much of the Pacific 

Northwest old growth will all eventually die; the loss of Douglasfir changes the nature of the stand from a successional stage to a 

quasi-climax stage dominated by shade-tolerant tree species. Thus, 

old growth is perishable. Science suggests that thoughtful management could produce complex forests that provide many of the functions of old growth and habitat for many of the species found in old 

growth. Of course, the full biodiversity associated with old growth 

will never be known. Complex forests created by managers will take 

hundreds of years to develop the stature of natural old growth. Thus, 

managers will never know if they were successful in recreating old 

growth. Thus, for all practical conservation purposes, managers cannot recreate old growth or manipulate old growth with predictable 

results. The public resistance to further destruction of the natural 

legacies in the Pacific Northwest suggests further harvesting of old 

growth will likely evoke more protests, sometimes destruction of 

equipment, and litigation.

Common Questions

The last century of exploitation of natural resources and societal 

conflicts over the disposition of natural resources has been intense 

as large numbers of people moved westward across North America 

and as preindustrial countries developed. These issues culminated 

and permeated in forests and human communities in the Pacific 

Northwest (see, e.g., Behan 2001, Daily and Ellison 2002, Golden 

1999, Harris 1996, Kemmis 2001, and Satterfield 2002). Many lessons have been rendered about ecology and the sociology of protection, restoration, maintenance, and utilization of biodiversity (sidenotes 66, 67). Whereas silviculture is occasionally questioned in the 

management of nonindustrial and industrial private forests, its use 

is coming under closer scrutiny in the management of public forests. 

In particular, the use of silviculture to achieve ecological benefits in 

second-growth forests in late-successional reserves has raised several questions. How can such questions, often based on the history of 

mismanagement and mistrust of agencies and experts, be answered? 

It appears the sociology of conservation needs more development 

than ecosystem management does. Dryzek (1992) describes the 
C H A P T E R 8 AIM for Resilient Forests 347

Sidenote 68—General 

principles of landscape management (Lindenmayer and Franklin 

2002):

 Maintain connectivity.

 Maintain landscape heterogeneity.

 Maintain ecosystem complexity.

 Maintain intact aquatic systems.

 Spread risk—do not do the 

same thing everywhere.

three main institutions of our society (capitalism, “liberal” democracy, and the administrative state) as thoroughly inept as regards 

to ecology and conservation. There is no cookbook approach that 

will achieve intentionality; management must be site specific and in 

the context of a spatial hierarchy. Thus, I will list only management 

technique tactics that can be integrated into AIM for multiple values 

if and when the mechanism for achieving discussion, collaborative 

learning, and collaborative management replace adversarial, position-based jousting (see Thomas 2002 for further discussion of the 

“The Conflict Industry”).

The toolbox includes legacy retention and maintenance, planting and seeding, control of species composition, exotic species management, precommercial thinning, underplanting, variable-density 

thinning, coarse woody debris augmentation, cavity tree augmentation, variable-retention harvesting systems, and uneven-age management systems at the level of biotic communities. At the landscape level, management (sidenote 68) includes protection of special 

landscape elements; transportation systems; recreation opportunities 

and recreational access management; harvesting of timber and nontimber forest products; aquatic conservation strategies for wetlands, 

riparian areas, and unstable slopes; extractions of minerals and fossil 

fuels; locations and routing of highways, power lines, and communication towers; and reserves. Reserve management is a field unto 

itself: in the Pacific Northwest, 3 million hectares are in congressionally reserved lands; 3 million hectares have been administratively withdrawn into late-successional reserves, over 600,000 hectares have been constrained in adaptive management areas, and 1.1

million hectares are in riparian reserves, for 8.3 million hectares of 

federally administrated forests on which management is restricted 

and tightly regulated. Federal lands available for collaborative management include 1.6 million hectares of “matrix” lands embedded in 

7.7 million hectares of reserves (Haynes and Perez 2001). Additional 

state, county, and private lands have been constrained under designation as parks, habitat conservation plans, riparian buffer areas, and 

areas of unstable soil.

Will Plantations Develop Into Old Growth?

The answer to this question is “No,” for the very same reasons that 

old growth is unique and irreplaceable in the previous discussion. 

Will plantations in late-successional reserves develop into complex 

forests that have many of the attributes of old growth? The answer 
348 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values

to this question is a qualified “Yes, but it would take centuries.” 

There are two qualifications. First, and most obvious, is that there 

be no global climate change of sufficient magnitude to change the 

type of vegetation that would naturally occur in the region. Second, 

the speed at which second growth develops late-seral character depends on the multitude of factors that led to its current condition. 

The timber harvest that created the second growth was quite unlike 

the natural disturbance that led to old growth. Clearcutting, burning, and planting often produce simplified, depauperate forests that 

could take more than 250 years to develop conditions suitable for 

recolonization by late-seral species. The sooner the canopy closes 

and the longer it remains closed in a plantation, the less likely a 

wide variety of seeds of native species will be retained in the soil, 

including those of shade-tolerant trees (Halpern et al. 1999). In 

some cases, the existing stand may have to be destroyed by natural 

disturbances and replaced by a larger variety of trees before development can proceed. Monocultures of small, dense trees are often 

more susceptible to disease and wind than natural stands and lack 

resilience, as well as resistance. Partial cuttings and “sloppy” clearcuts 

that left substantial legacies from a preceding old-growth stand may 

function as habitat for many late-seral species within 10 to 200 years 

depending on the amount of disturbance at harvest and subsequent 

natural disturbances. The speed of colonization of simplified second-growth forest by missing elements of natural forest will depend 

on the size and context of the forest in question. Although, modern clearcuts on federal lands often were less than 15 hectares (an 

area that could be colonized rapidly if surrounded by intact natural 

systems), extensive areas cumulatively were clearcut over several decades, and recolonization of these areas could take much longer. A 

key point is that development toward old growth is not inexorable; 

multiple alternative, relatively long-lived states exist for naturally regenerated forests and are more likely with forests regenerated with 

conventional silviculture.

Is Active Management Better Than Leaving Second 

Growth Alone? 

The probability of active management accelerating the development 

of late-seral forest conditions will increase with the intentionality of 

the management and decrease with time since stand establishment. 

Certainly, precommercial thinning of densely stocked monocultures 

less than 20 years old is desirable, and its efficacy will increase with 
C H A P T E R 8 AIM for Resilient Forests 349

provisions for favoring volunteer seedlings of additional tree species, 

including deciduous species and for favoring tall shrubs. Conventional commercial thinning is more likely to be deleterious than not. 

Thinnings that are too light or too heavy are likely to be deleterious. 

Biodiversity management with variable-density thinning favoring a 

diversity of species, cavity tree retention, coarse woody debris conservation, and underplanting, cavity-tree creation, and coarse woody 

debris augmentation, when warranted, should increase the probability that the ecosystem will quickly develop late-seral characteristics 

(Carey 2000b, 2001; Carey and Harrington 2001; Carey et al. 1999b; 

Thysell and Carey 2000, 2001a; Wilson and Carey 2000).

Will Active Management of Second Growth Produce 

Negative Effects?

Short-term negative effects are unavoidable. Thinning will disturb 

the soil, kill trees, disrupt canopy connectivity, and reduce sporocarp production by belowground fungi. Thinning operations are 

destructive of plants and animals in the forest floor. Achlorophyllous mycotrophs (e.g., Indianpipe) may be negatively affected over 

the long term, but these negative impacts might be mitigated by 

leaving small unthinned patches within the stands. Thinning may 

decrease northern flying squirrel populations in the short term (less 

than 5 years). The same can be said of natural disturbances. Commercial thinning requires roads and use of heavy equipment within 

the forest with attendant disturbance effects. The positive benefits 

of thinning will most likely begin accruing after 5 years and could 

continue for a decade or more. Thus, active management for ecological values trades short-term negative effects for long-term gains. 

Commercial thinnings, by definition, remove biomass in the form of 

wood. Many second-growth stands contain many more stems than 

naturally young stands, and reduction in stem density is essential 

for a number of stand developmental processes. This reduction in 

biomass, however, can be at the expense of foregone standing dead 

trees, coarse woody debris recruitment, and total forest-floor organic 

matter with unintended negative consequences. Thus, high intentionality must be used in taking action to maintain (or enhance) 

decadence processes during thinning.

Suggested Reading

Barabási, A.-L. 2003. Linked: how everything is connected to everything else and what it means for business, science, and everyday life. New York: Plume/Penguin. 294 p.

Brown, B. 1982 [2003]. Mountain in the clouds: a search for the 

wild salmon. Seattle: University of Washington Press. 249 p.

Carey, A.B. 2003a. Biocomplexity and restoration of biodiversity in 

temperate coniferous forest: inducing spatial heterogeneity with 

variable-density thinning. Forestry. 76(2): 127–136.

Carey, A.B. 2003c. Restoration of landscape function: reserves or 

active management? Forestry. 76(2): 221–230.

Carey, A.B.; Lippke, B.R.; Sessions, J. 1999c. Intentional systems 

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353

English Equivalents

When you know: Multiply by: To find:

Millimeters.0394 Inches

Centimeters.394 Inches

Meters3.28 Feet

Square meters1.20 Square yards

Square meters per hectare4.367 Square feet per acre

Cubic meters per hectare14.292 Cubic feet per acre

Kilometers.621 Miles

Square kilometers.386 Square miles

Hectares2.47 Acres

Hectares 259 Square miles

Kilograms per hectare.893 Pounds per acre

Megagrams per hectare.446 Tons per acre

Celsius1.80 and add 32 Fahrenheit

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Common and Scientific Names of Speciesa

Common name Scientific name

VASCULAR PLANTS:

Alaska oniongrass Melica subulata (Griseb.) Scribn. 

Aleutian maidenhair Adiantum aleuticum (Rupr.) Paris 

American beech Fagus grandifolia Ehrh.

American trailplant Adenocaulon bicolor Hook.

American vetch Vicia americana Muhl. ex Willd.

Antelope bitterbush Purshia tridentata (Pursh) DC.

Artic sweet coltsfoot Petasites frigidus (L.) Fries var. palmatus (Ait.) Cronq.

Baldhip rose Rosa gymnocarpa Nutt.

Balsam fir Abies balsamea (L.) P. Mill.

Basswood Tilia americana L.

Bearberry Arctostaphylos uva-ursi (L.) (Spreng.)

Bearded fescue Festuca subulata Trin.

Big chickweed Cerastium fontanum Baumg. ssp. vulgare (Hartman) Greuter & Burdet 

Bigleaf maple Acer macrophyllum Pursh

Bird’s-foot trefoil Lotus corniculatus L.

Bitter cherry Prunus emarginata (Dougl. ex Hook.) D. Dietr.

Bittersweet Solanum dulcamera L.

Black cottonwood Populus balsamifera L. ssp. trichocarpa (Torr. & Gray ex Hook.) Brayshaw

Black hawthorn Crataegus douglasii Lindl.

Blackcap Rubus leucodermis Dougl. ex Torr. & Gray

Blue wildrye Elymus glaucus Buckl. ssp. glaucus

British Columbia wildginger Asarum caudatum Lindl.

Broadleaf starflower Trientalis borealis Raf. ssp. latifolia (Hook.) Hulten

Broadpetal strawberry Fragaria virginiana Duchesne ssp. platypetala (Rydb.) Staudt

Bull thistle Cirsium vulgare (Savi) Ten.

Bur oak Quercus macrocarpa Michx.

California blackberry Rubus ursinus Cham. & Schlecht.

Appendix
California hazelnut Corylus cornuta Marsh. var. californica (A. DC.) Sharp

California huckleberry Vaccinium ovatum Pursh

California pinefoot Pityopus californica (Eastw.) Copel. f.

California red fir Abies magnifica A. Murr.

Canada fleabane Conyza canadensis (L.) Cronq.

Canada thistle Cirsium arvense (L.) Scop.

Candyflower Claytonia sibirica L. var. sibirica

Canyon live oak Quercus chrysolepis Liebm.

Cascade Oregongrape Mahonia nervosa (Pursh) Nutt.

Cascara buckhorn Frangula purshiana (DC.) Cooper

Chamisso sedge Carex pachystachya Cham. ex Steud.

Chaparral willowherb Epilobium minutum Lindl. ex Lehm.

Chestnut oak Quercus prinus L.

Cleavers Galium aparine L.

Clustered thistle Cirsium brevistylum Cronq.

Coastal burnweed Erechtites minima (Poir.) DC. 

Coastal wormwood Artemisia suksdorfii Piper 

Colonial bentgrass Agrostis capillaris L. 

Columbia brome Bromus vulgaris (Hook.) Shear

Common ladyfern Athyrium filix-femina (L.) Roth

Common nipplewort Lapsana communis L.

Common plantain Plantago major L.

Common prince’s-pine Chimaphila umbellata (L.) W. Bart.

Common selfheal Prunella vulgaris L.

Common sheep sorrel Rumex acetosella L.

Common snowberry Symphoricarpos albus (L.) Blake

Common sowthistle Sonchus oleraceus L.

Common St. Johnswort Hypericum perforatum L.

Common velvetgrass Holcus lanatus L.

Creeping buttercup Ranunculus repens L. var. repens

Creeping snowberry Symphoricarpos hesperius G.N. Jones

Crinkleawn fescue Festuca subuliflora Scribn.

Curled starwort Stellaria crispa Cham. & Schlecht.

Curly dock Rumex crispus L.

Cutleaf blackberry Rubus laciniatus Willd.

Deer-fern Blechnum spicant (L.) Roth

Desert deervetch Lotus micranthus Benth.

Devilsclub Oplopanax horridus Miq.

Dewey’s sedge Carex deweyana Schwein.

Douglas-fir Pseudotsuga menziesii (Mirb.) Franco var. menziesii

Drops-of-gold Disporum hookeri (Torr.) Nichols.

Eastern hemlock Tsuga canadensis (L.) Carr.

430 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Elderberry Sambucus spp.

Enchanter’s nightshade Circaea alpina L.

Engelmann spruce Picea engelmannii Parry ex Engelm.

English holly Ilex aquifolium L. 

English ivy Hedera helix L.

Evergreen violet Viola sempervirens Greene

Field clover Trifolium campestre Schreb.

Field mint Mentha canadensis L.

Fireweed Epilobium angustifolium L.

Flowering dogwood Cornus florida L.

Fragrant bedstraw Galium triflorum Michx.

Giant chinquapin Chrysolepis chrysophylla (Dougl. ex Hook.) Hjelmqvist

Giant sequoia Sequoiadendron giganteum (Lindl.) Buchh.

Giant vetch Vicia nigricans Hook. & Arn. ssp. gigantea (Hook.) Lassetter & Gunn.

Glaucus willowherb Epilobium glaberrimum Barbey ssp. glaberrimum

Grand fir Abies grandis (Dougl. ex D. Don) Lindl.

Hairy catsear Hypochaeris radicata L.

Hickory Carya spp.

Himalayan blackberry Rubus discolor Weihe & Nees

Howell’s violet Viola howellii Gray

Idaho buttercup Ranunculus uncinatus D. Don ex G. Don var. parviflorus (Torr.) L. Benson

Idaho fescue Festuca idahoensis Elmer

Incense cedar Calocedrus decurrens (Torr.) Florin

Indian plum Oemlaria cerasiformis (Torr. & Gray ex Hook. & Arn.) Landon

Indianpipe Monotropa uniflora L.

Jack pine Pinus banksiana Lamb.

Lamp rush Juncus effusus L. var. gracilis Hook.

Largeleaf avens Geum macrophyllum Willd. var. macrophyllum

Largeleaf sandwort Moehringia macrophylla (Hook.) Fenzl

Leafy pea Lathyrus polyphyllus Nutt.

Licorice fern Polypodium glycyrrhiza D.C. Eat.

Little prince’s-pine Chimaphila menziesii (R. Br. ex D. Don) Spreng.

Lodgepole pine Pinus contorta Dougl. ex Loud.

Longleaf pine Pinus palustris Mill.

Longstalk starwort Stellaria longipes Goldie

Manzanita Arctostaphylos spp.

Miner’s lettuce Claytonia perfoliata Donn ex Willd. ssp. perfoliata

Mountain hemlock Tsuga mertensiana (Bong.) Carr.

Mountain woodfern Dryopteris campyloptera Clarkson

Narrowleaf plantain Plantago lanceolata L.

Northern red oak Quercus rubra L.

Northwestern twayblade Listera caurina Piper

P A R T I & I I Appendix 431
Oceanspray Holodiscus discolor (Pursh) Maxim.

Orange honeysuckle Lonicera ciliosa (Pursh) Poir. ex DC.

Oregon ash Fraxinus latifolia Benth.

Oregon white oak Quercus garryana Dougl. ex Hook.

Oxeye-daisy Leucanthemum vulgare Lam.

Pacific bleeding heart Dicentra formosa (Haw.) Walp.

Pacific dogwood Cornus nuttallii Audubon ex Torr. & Gray

Pacific madrone Arbutus menziesii Pursh 

Pacific rhododendron Rhododendron macrophyllum D. Don ex G. Don

Pacific silver fir Abies amabilis (Dougl. ex Loud.) Dougl. ex Forbes

Pacific strawberry Fragaria crinita Rydb.

Pacific trillium Trillium ovatum Pursh

Pacific yew Taxus brevifolia Nutt.

Paper birch Betula papyrifera Marsh.

Pennsylvania bittercress Cardamine pensylvanica Muhl. ex Willd.

Pink honeysuckle Lonicera hispidula (Lindl.) Dougl. ex Torr. & Gray

Pink wintergreen Pyrola asarifolia Michx. ssp. bracteata (Hook.) Haber 

Pioneer violet Viola glabella Nutt.

Ponderosa pine Pinus ponderosa P. & C. Lawson 

Poverty rush Juncus tenuis Willd.

Prickly sowthistle Sonchus asper (L.) Hill

Purple foxglove Digitalis purpurea L.

Pursh’s buckthorn Frangula purshiana (DC.) Cooper

Quaking aspen Populus tremuloides Michx.

Red alder Alnus rubra Bong.

Red baneberry Actaea rubra (Ait.) Willd.

Red clover Trifolium pratense L.

Red elderberry Sambucus racemosa L.

Redflower currant Ribes sanguineum Pursh

Red huckleberry Vaccinium parvifolium Sm.

Red maple Acer rubrum L.

Red pine Pinus resinosa Soland.

Red spruce Picea rubens Sarg. 

Redwood Sequoia sempervirens (Lamb. ex D. Don) Endl.

Reed canarygrass Phalaris arundinacea L.

Riverbank lupine Lupinus rivularis Dougl. ex Lindl.

Robert geranium Geranium robertianum L.

Rose spirea Spiraea douglasii Hook. var. douglasii

Salal Gaultheria shallon Pursh 

Salebrosa goldenrod Solidago canadensis L. var. salebrosa (Piper) M.E. Jones

Salmonberry Rubus spectabilis Pursh

Saskatoon serviceberry Amelanchier alnifolia (Nutt.) Nutt. ex M. Roemer

432 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Scarlet oak Quercus coccinea Muenchh.

Scotchbroom Cytisus scoparius (L.) Link

Scouler willow Salix scouleriana Barratt ex Hook.

Scouler’s harebell Campanula scouleri Hook. ex A. DC.

Silver hairgrass Aira caryophyllea L.

Sitka alder Alnus viridis (Vill.) Lam. & DC. ssp. sinuata (Regel) A.& D. Löve

Sitka mountain ash Sorbus sitchensis M. Roemer var. sitchensis

Sitka spruce Picea sitchensis (Bong.) Carr.

Slender hairgrass Deschampsia elongata (Hook.) Munro

Small camas Camassia quamash (Pursh) Greene

Smallflower nemophila Nemophila parviflora Dougl. ex Benth.

Small-flowered woodrush Luzula parviflora (Ehrh.) Desv.

Smooth hawksbeard Crepis capillaris (L.) Wallr.

Snowberry Gaultheria spp.

Snowbrush ceanothus Ceanothus velutinus Dougl. ex Hook.

Southern beech Nothofagus Blume, nom. cons.

Spike bentgrass Agrostis exarata Trin.

Spoonleaf purple everlasting Gamochaeta purpurea (L.) Cabrera

Starry false Solomon’s seal Maianthemum stellatum (L.) Link

Stinging nettle Urtica dioica L.

Subalpine fir Abies lasiocarpa (Hook.) Nutt. var. lasiocarpa

Sugar maple Acer saccharum Marsh

Summer coralroot Corallorhiza maculata (Raf.) Raf.

Sweet after death Achlys triphylla (Sm.) DC.

Sweet vernalgrass Anthoxanthum odoratum L.

Sweetcicely Osmorhiza berteroi DC.

Tall blue lettuce Lactuca biennis (Moench) Fern.

Tall oatgrass Arrhenatherum elatius (L.) Beauv. ex J. & K. Presl

Tall Oregongrape Mahonia aquifolium (Pursh) Nutt.

Tanoak Lithocarpus densiflorus (Hook. & Arn.) Rehd.

Tansy ragwort Senecio jacobaea L.

Thimbleberry Rubus parviflorus Nutt.

Threeleaf foamflower Tiarella trifoliata L.

Tiger lily Lillium columbianum hort. ex Baker

Timothy Phleum pratense L.

Toad rush Juncus bufonius L.

Tuliptree Liriodendron tulipifera L.

Twinflower Linnaea borealis L.

Variableleaf collomia Collomia heterophylla Dougl. ex Hook.

Vine maple Acer circinatum Pursh

Wall-lettuce Mycelis muralis (L.) Dumort.

Western anemone Anemone deltoidea Hook.

P A R T I & I I Appendix 433
Western brackenfern Pteridium aquilinum (L.) Kuhn.

Western buttercup Ranunculus occidentalis Nutt.

Western fescue Festuca occidentalis Hook.

Western hemlock Tsuga heterophylla (Raf.) Sarg.

Western pearly everlasting Anaphalis margaritacea (L.) Benth.

Western rattlesnake plantain Goodyera oblongifolia Raf.

Western redcedar Thuja plicata Donn. ex D. Donn.

Western serviceberry Amelanchior alnifolia (Nutt.) Nutt. ex M. Roemer

Western swordfern Polystichum munitum (Kaulfuss) K. Presl

Western white pine Pinus monticola Dougl. ex D. Don

White clover Trifolium repens L.

White oak Quercus alba L.

White spruce Picea glauca (Moench) Voss 

White-flowered hawkweed Hieracum albiflorum Hook.

White insideout flower Vancouveria hexandra (Hook.) Morr. & Dcne.

Whiteveined wintergreen Pyrola picta Sm.

Willow spp. Salix spp.

Woodland ragwort Senecio sylvaticus L.

Woodrush Luzula campestris (L.) DC.

Yellow birch Betula alleghaniensis Britton

Yellow-cedar Chamaecyparis nootkatensis (D. Don) Spach

Yellow hairgrass Aira praecox L.

Yerba buena Satureja douglasii (Benth.) Briq.

PLANT PATHOGENS AND PESTS:

Arbutus canker Nattrassia mangiferae

Asian longhorned beetle Anoplophora glabripennis

Bark beetle Dendroctonus spp.

Beech bark desease Nectria coccinea var. faginata

Chestnut blight Cryphonectria parasiti

Deer tick Ixodes dammini

Douglas-fir tussock moth Orygia pseudotsugata McDunnough

Dutch elm disease Ophiostoma ulmi

Dwarf mistletoe Arceuthobium spp.

Emerald ash borer Agrilus planipennis

European pine shoot beetle Tomicus piniperda L.

Groundhog tick Ixodes cookei Packard, 1869

Hemlock woolly adelgid Adelges tsugae Annand

Larch casebearer Coleophora laricella Hubner

Madrone canker Fusicoccum aesculi

Mistletoe Phoradendron spp.

Mountain pine beetle Dendroctonus ponderosae

434 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
AMPHIBIANS AND REPTILES:

Bullfrog Rana catesbeiana Shaw, 1802

Clouded salamander Aneides ferreus Cope, 1869

Cope’s giant salamander Dicamptodon copei Nussbaum, 1970

Ensatina Ensatina eschscholtzii Gray, 1850

Larch mountain salamander Plethodon larselli Burns, 1954

Long-toed salamander Ambystoma macrodactylum Baird, 1849

Northern alligator lizard Gerrhonotus coeruleus Wiegmann, 1828

Northern spring peeper Pseudacris crucifer Wied-Neuwied, 1838

Northwestern garter snake Thamnophis ordinoides Baird & Girard, 1852

Northwestern salamander Ambystoma gracile Baird, 1859

Olympic torrent salamander Rhyacotriton olympicus Gaige, 1917

Oregon slender salamander Batrachoseps wrighti Bishop, 1937

Pacific tree frog Pseudacris regilla Barid & Girard, 1852

Red-legged frog Rana aurora Baird & Girard, 1852

Rough-skinned newt Taricha granulosa Skilton, 1849

Rubber boa Charina bottae Blainville, 1835

Spring peeper Pseudacris crucifer

Tailed frog Ascaphus truei

Western red-backed salamander Plethodon vehiculum Cooper, 1860

Western tailed frog Ascaphus truei Stejneger, 1899

Western toad Bufo boreas Baird & Girard, 1852

Wood frog Rana sylvatica LeConte, 1825

MAMMALS:

American beaver Castor canadensis Kuhl.

American bison Bison bison

American black bear Ursus americanus Pallas, 1780

American marten Martes americana

Root rot Phellinus spp.

Pandora pinemoth Coloradia pandora Blake, 1863

Southern pine beetle Dendroctonus frontalis Zimmerman

Spruce beetle Dendroctonus rufipennis Kirby

Sudden oak death fungus Phytophthora ramorum 

Swiss needle cast Phaeocryptopus gaeumannii T. Rohde Petr.

Velvet-top fungus Phaeolus schweinitzii 

Western spruce budworm Choristoneura occidentalis Freeman

White pine blister rust Cronartivu ribicola

MOLLUSKS:

Burrington jumping slug Hemphillia burringtoni

Banana slug Ariolimax columbianus

P A R T I & I I Appendix 435
American porcupine Erethizon dorsatum Linnaeus, 1758

American water shrew Sorex palustris Richardson

Blacktail deer Odocoileus hemionus Rafinesque, 1817

Bobcat Felis rufus

Bushy-tailed woodrat Neotoma cinerea

California myotis Myotis californicus Audubon & Bachman, 1842

California red-backed vole Cleithrionomys californicus

Coast mole Scapanus orarius True, 1896

Columbian deer mouse Peromyscus oreas Bangs. 

Coyote Canis latrans Say, 1823

Deer mouse Peromyscus maniculatus Wagner, 1845

Douglas’ squirrel Tamiasciurus douglasii Bachman, 1839

Dusky-footed woodrat Neotoma fuscipes

Eastern cottontail Sylvilagus floridanus J.A. Allen, 1890

Eastern gray squirrel Sciurus carolinensis Gmelin, 1788

European red squirrel Sciurus vulgaris Linnaeus, 1758 ssp. exalbudus Pallas, 1778

Fisher Martes pennanti Erxleben, 1777

Golden-mantled ground squirrel Spermophilus lateralis Say

Gray wolf Canis lupus

House mouse Mus musculus Linnaeus, 1758

Keen’s mouse Peromyscus keeni Rhoads

Least chipmunk Tamias minimus Bachman, 1839

Long-tailed vole Microtus longicaudus Murriam, 1888

Long-tailed weasel Mustela frenata Lichtenstein, 1831

Lynx Lynx canadensis Kern, 1792

Meadow vole Microtus pennsylvanicus Ord, 1815

Montane shrew Sorex monticolus Merriam, 1890

Moose Alces alces

Mountain beaver Aplodonia rufa Rafinesque, 1817

Mountain lion Felis concolor Linnaeus

Mule deer Odocoileus hemionus Rafinesque, 1817

Northern flying squirrel Glaucomys sabrinus Shaw, 1801

Oregon creeping vole Microtus oregoni Bachman, 1839

Pacific jumping mouse Zapus trinotatus Rhoads, 1895

Pacific marsh shrew Sorex bendirii Merriam, 1884

Racoon Procyon lotor Linnaeus, 1758

Red fox Vulpes vulpes Linnaeus, 1758

Red tree vole Arborimus longicaudus True, 1890

Richardson’s ground squirrel Spermophilus richardsonii Sabine, 1822

Rocky mountain elk Cervus elaphus nelsoni

Rocky mountain goat Oreamnos americanus

Roosevelt elk Cervus elaphus roosevelti

436 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Shorttail weasel Mustela erminea Linnaeus, 1758

Shrew mole Neurotrichus gibbsii Baird, 1858

Russian flying squirrel Pteromys volans Linnaeus, 1758

Siskiyou chipmunk Tamias siskiyou

Snowshoe hare Lepus americanus Erxleben, 1777

Southern red-backed vole Clethrionomys gapperi Vigors, 1830

Townsend’s big-eared bat Plecotus townsendii Cooper, 1837

Townsend’s chipmunk Tamias townsendii Bachman, 1839

Townsend’s mole Scapanus townsendii Bachman, 1839

Trowbridge’s shrew Sorex trowbridgii Baird, 1858

Vagrant shrew Sorex vagrans Baird, 1858

Virginia opposum Didelphis virginiana Kerr, 1792

Western gray squirrel Sciurus griseus Ord, 1818

Western heather vole Phenacomys intermedius

Western red-backed vole Clethrionomys californicus

White-footed mouse Peromyscus leucopus Rafinesque

Wolverine Gulo gulo

BIRDS:

American crow Corvus brachyrhynchos Brehm, 1822

American dipper Cinclus mexicanus Swainson, 1827

American robin Turdus migratorius Linnaeus, 1766

Bald eagle Haliaeetus leucocephalus Linnaeus, 1766

Band-tailed pigeon Columba fasciata Say, 1823

Barn owl Tyto alba Scopoli, 1769

Barn swallow Hirundo rustica Linnaeus, 1758

Barred owl Strix varia Barton, 1799

Black-capped chickadee Parus atricapillus Linnaeus, 1766

Black-headed grosbeak Pheucticus melanocephalus Swainson, 1827

Black-throated gray warbler Dendroica nigrescens Townsend, 1837

Blue grouse Dendragapus obscurus Say, 1823

Bobwhite Colinus virginianus Linnaeus, 1758

Boreal owl Aegolius funereus Linnaeus, 1758

Brown creeper Certhia americana Bonaparte, 1838

Brown-headed cowbird Molothrus ater Boddaert, 1783

Canada goose Branta canadensis Linnaeus, 1758

Cedar waxwing Bombycilla cedrorum Vieillot, 1808

Chestnut-backed chickadee Parus rufescens Townsend, 1837

Chipping sparrow Spizella passerina Bechstein, 1798

Chukar Alectoris chukar Gray, 1830

Common bushtit Psaltriparus minimus Townsend, 1837

Common nighthawk Chordeiles minor Forster, 1771

Common raven Corvus corax Linnaeus, 1758

P A R T I & I I Appendix 437
Cooper’s hawk Accipiter cooperii Bonaparte, 1828

Dark-eyed junco Junco hyemalis Linnaeus, 1758

Downy woodpecker Picoides pubescens Linnaeus, 1766

Golden-crowned kinglet Regulus saltrapa Lichtenstein, 1823

Gray jay Perisoreus canadensis Linnaeus, 1766

Great blue heron Ardea herodias Linnaeus, 1758

Great-horned owl Bubo virginianus Gmelin, 1788

Hairy woodpecker Picoides villosus Linnaeus, 1766

Hermit thrush Catharus guttatus Pallas, 1811

Hermit warbler Dendroica occidentalis Townsend, 1837

Hutton’s vireo Vireo huttoni Cassin, 1851

Mallard Anas platyrhynchos Linnaeus, 1758

Marbled murrelet Brachyramphus marmoratus

Mourning dove Zenaida macroura Linnaeus, 1758

Northern flicker Colaptes auratus Linnaeus, 1758

Northern goshawk Accipiter gentilis Linnaeus, 1758

Northern pygmy owl Glaucidium gnoma Wagler, 1832

Northern saw-whet owl Aegolius acadicus Gmelin, 1788

Northern spotted owl Strix occidentalis Xantus de Vesey, 1860

Olive-sided flycatcher Contopus borealis Swainson, 1832

Orange-crowned warbler Vermivora celata Say, 1823

Pacific slope flycatcher Empidonax difficilis Baird, 1858

Passenger pigeons Ectopistes migratorius

Phainopepla Phainopepla nitens Swainson, 1838

Pileated woodpecker Dryocopus pileatus Linnaeus, 1758

Pine siskin Carduelis pinus Wilson, 1810

Purple finch Carpodacus purpureus Gmelin, 1789

Red crossbill Loxia curvirostra Linnaeus, 1758

Red-breasted nuthatch Sitta canadensis Linnaeus, 1766

Red-breasted sapsucker Sphyrapicus ruber Gmelin, 1788

Red-naped sapsucker Sphyrapicus nuchalis Baird, 1858

Red-tailed hawk Buteo jamaicensis Gmelin, 1788

Red-winged blackbird Agelaius phoeniceus Linnaeus, 1766

Ring-necked pheasant Phasianus colchicus Linnaeus, 1758

Ruby-crowned kinglet Regulus calendula Linnaeus, 1766

Ruffed grouse Bonasa umbellus Linnaeus, 1766

Rufous hummingbird Selasphorus rufus Gmelin, 1788

Rufous-sided towhee Pipilo erythrophthalmus Linnaeus, 1758

Sharp-shinned hawk Accipiter striatus Vieillot, 1807

Solitary vireo Vireo solitarius Wilson, 1810

Song sparrow Melospiza melodia Wilson, 1810

Steller’s jay Cyanocitta stelleri Gmelin, 1788

438 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Swainson’s thrush Catharus ustulatus Nuttall, 1840

Tengmalm’s owl Aegolius funereus Kaup, 1829

Townsend’s solitaire Myadestes townsendi Audobon, 1838

Townsend’s warbler Dendroica townsendi Townsend, 1837

Tree swallow Tachycineta bicolor Vieillot, 1808

Turkey vulture Cathartes aura Linnaeus, 1758

Varied thrush Ixoreus naevius Gmelin, 1789

Vaux’s swift Chaetura vauxii Towns.

Warbling vireo Vireo gilvus Vieillot, 1808

Western bluebird Sialia mexicana Swainson, 1832

Western screech owl Otus kennicotti Elliot, 1867

Western tanager Piranga ludoviciana Wilson, 1811

White-crowned sparrow Zonotrichia leucophrys Forster, 1772

Willow flycatcher Empidonax traillii Audobon, 1828

Wilson’s warbler Wilsonia pusilla Wilson, 1811

Winter wren Troglodytes troglodytes Linnaeus, 1758

Yellow-rumped warbler Dendroica coronata Linnaeus, 1766

FISH:

Chinook salmon Oncorhynchus tshawytscha

Chum salmon Oncorhynchus keta

Coho salmon Oncorhynchus kisutch

Pink salmon Oncorhynchus gorbuscha

Sockeye salmon Oncorhynchus nerka

Steelhead salmon Oncorhynchus nerka

HYPOGEOUS FUNGI (truffles):

Alpova diplophloeus (Zeller & Dodge) Trappe & Smith

Elaphomyces granulatus Fr.

Elaphomyces muricatus Fr.

Endogone lactiflua Bk. & Bk.

Endogone pisiformis Link:Fr.

Gautieria monticola Harkn.

Gautieria spp.

Genabea cerebriformis (Harkn.) Trappe

Genea harknessii Gilkey

Genea intermedia Gilkey

Glomus spp.

Glomus macrocarpum Tul. & Tul.

Glomus mosseae (Nicol. & Gerd.) Gerd. & Trappe

Hydnotrya variiformis Gilkey

Hymenogaster sublilacinus Smith

P A R T I & I I Appendix 439
EPIGEOUS FUNGI (mushrooms):

Agaricus albolutescens Zeller

Agaricus diminutivus Pk.

Agaricus micromegathus Pk.

Agaricus silvicola (Vitt.) Pk.

Agrocybe praecox (Fr.) Fayod

Albatrellus pes-caprae (Fr.) Pouzar

Aleuria aurantiaca (Fr.) Fuckel

Hysterangium coriaceum Hesse

Hysterangium crassirhachis Zeller & Dodge

Hysterangium setchellii Fischer

Leucangium carthusiana (Tul. & Tul.) Paoletti

Leucogaster candidus (Harkn.) Fogel comb. ined.

Leucogaster citrinus (Harkn.) Zeller & Dodge

Leucogaster gelatinosus Fogel nom. ined.

Leucogaster rubescens Zeller & Dodge

Leucogaster spp.

Leucophleps magnata Harkn. 

Leucophleps spinispora Fogel

Melanogaster ambiguus (Vitt.) Tul. & Tul.

Melanogaster euryspermus (Zeller & Dodge) Zeller

Melanogaster natsii Wang, Trappe, & Castellano spp.

Melanogaster thiersii Wang, Trappe, & Castellano spp.

Melanogaster trappei Wang spp.

Melanogaster tuberiformis Corda in Sturm

Melanogaster variegatus (Vitt.) Tul. & Tul.

Pachyphloeus thysellii Colgan & Castellano, nom. ined.

Piloderma fallax (Lib.) Stalp.

Radiigera fuscogleba Zeller

Rhizopogon hawkerae Smith

Rhizopogon parksii

Rhizopogon rogersii Smith

Rhizopogon subareolatus Smith

Rhizopogon villosulus Zeller

Rhizopogon vinicolor Smith

Rhizopogon vulgaris (Vittad.) M. Lange

Scleroderma hypogaeum Zeller

Truncocolumella citrina Zeller

Tuber anniae Colgan & Trappe

Tuber gibbosum Harkn.

Tuber monticola Harkn.

440 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Amanita gemmata var. exannulata Lange

Amanita gemmata var. gemmata (Fr.) Bert.

Amanita pantherina (DC:Fr.) Schum.

Amanita porphyria (A.& S. ex Fr.) Secr.

Amanita silvicola Kauffm.

Amanita smithiana Bas.

Armillaria mellea (Vahl ex Fr.) Karsten

Auriscalpium vulgare S.F. Gray

Bolbitius spp.

Boletus chrysenteron Fr.

Boletus zelleri Murr.

Cantharellus cibarius Fr.

Cantharellus subalbidus Smith & Morse

Cantharellus tubaeformis Fr.

Clavaria spp.

Clavulina cinerea (Fr.) Schroet.

Clavulina cristata (Fr.) Schroet.

Clavulinopsis corniculata (Schaeff.:Fr.) Corner

Clavulinopsis laeticolor (Berk. & Curt.) R.H. Petersen

Clitocybe coniferophila H.E. Bigelow 

Clitocybe deceptiva H.E. Bigelow

Clitocybe dilatata Pers. ex Karsten

Clitocybe inversa (Fr.) Gill.

Collybia acervata (Fr.) Kummer 

Collybia alcalivirens Singer

Collybia butyracea (Fr.) Quel.

Collybia confluens (Pers. ex Fr.) Kummer

Collybia dryophila (Bull. ex Fr.) Kummer

Collybia fuscopurpurea (Pers.:Fr.) Kumm. 

Collybia oregonensis A.H. Smith

Collybia racemosa (Pers.:Fr.) Quél.

Coltricia cinnamomea ( Jacq.:Pers.) Murr.

Conocybe cyanopus (Atk.) Kühner

Conocybe tenera (Schaeff. ex Fr.) Kuhner

Coprinus micaceus (Bull. ex Fr.) Fr.

Coprinus plicatilis (Curt.:Fr.) Fr.

Coprinus sylvaticus Pk.

Cortinarius acutus Fr. 

Cortinarius alboviolaceus (Pers. ex Fr.) Fr.

Cortinarius angulosus Fr.

Cortinarius brunneus Fr.

Cortinarius californicus A.H. Smith

P A R T I & I I Appendix 441
Cortinarius cinnamomeus (Fr.) Fr. 

Cortinarius corrugatus Peck

Cortinarius cotoneus Fr. 

Cortinarius crassus Fr.

Cortinarius crystallinus Fr.

Cortinarius decipiens Fr.

Cortinarius duracinus Fr.

Cortinarius evernius Fr.

Cortinarius glaucopus (Schaeff.:Fr.) Fr.

Cortinarius hemitrichus Fr.

Cortinarius infractus (Pers.:Fr.) Fr.

Cortinarius laniger Fr. 

Cortinarius malachius Fr.

Cortinarius mucosus (Bull.:Fr.) Fr.

Cortinarius multiformis (Fr.) Fr.

Cortinarius nigrocuspidatus

Cortinarius obtusus Fr. 

Cortinarius olympianus A.H. Smith 

Cortinarius paleaceus Fr.

Cortinarius percomis Fr.

Cortinarius phoeniceus (Bull.) R. Maire

Cortinarius pinetorum (Fr.) Kauffman

Cortinarius plumiger (Fr.) Fr.

Cortinarius prasinus Fr.

Cortinarius pseudobolaris Maire sensu Smith

Cortinarius rubripes Kauffman

Cortinarius sanguineus (Fr.) Fr.

Cortinarius scaurus Fr. 

Cortinarius semisanguineus (Fr.) Gillet

Cortinarius subfoetidus A.H. Smith

Cortinarius subg. bulbopodium

Cortinarius subg. phlegmacium

Cortinarius subg. sericeocybe

Cortinarius subg. telemonia

Cortinarius superbus A.H. Smith

Cortinarius triformis Fr.

Cortinarius uliginosus Berk.

Cortinarius uraceus Fr.

Cortinarius vibratilis Fr.

Crepidotus herbarum (Pk.) Sacc.

Crepidotus mollis (Fr.) Stde.

Crucibulum laeve (Huds.) Kamb.

442 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Cudonia monticolaMains 

Cystoderma amianthinum (Scop.:Fr.) Fr.

Cystoderma fallax Smith & Singer

Cystoderma granulosum (Fr.) Fayod

Dacrymces palmatus (Schw.) Bres.

Entoloma nidorosum (Fr.) Quél. 

Entoloma rhodopolium (Fr.) Kumm. 

Fomitopsis cajanderi (Karsten) Kotlaba & Pouz.

Fomitopsis officinalis (Fr.) Bond. & Sing.

Fomitopsis pinicola (Fr.) Karst.

Fusicoccum aesculi (Byther 1999; Elliott 1999a, 1999b)

Galerina autumnalis (Pk.) Smith & Singer

Galerina heterocystis (Atk.) A.H. Smith 

Galerina marginata (Fr.) Kühner

Gomphidius glutenosus (Fr.) Fr.

Gomphidius oregonensis Peck

Gomphidius smithii Miller

Gomphidius subroseus Kauffman

Gomphus clavatus (Fr.) S.F. Gray 

Guepiniopsis alpinus (Tracy & Earle) Bres.

Gymnopilus bellulus (Peck) Murr.

Gymnopilus liquiritae (Pers.:Fr.) Karst.

Gymnopilus penetrans (Fr. ex Fr.) Murr.

Gymnopilus sapineus (Fr.) Maire

Hebeloma crustuliniforme (Bull. ex St. Amams) Quel.

Hebeloma sinapizans (Paulet:Fr.) Gill.

Helvella crispa Scop. ex Fr.

Helvella elastica Bull. ex St. Amans 

Helvella lacunosa Afz. ex Fr.

Hydnum repandum L. ex Fr.

Hydnum umbilicatum Pk.

Hygrocybe miniata (Fr.) Kumm.

Hygrophoropsis aurantiaca (Wulf. ex Fr.) Maire 

Hygrophorus calophyllus Karst.

Hygrophorus conicus (Fr.) Fr.

Hygrophorus glutinosus (Schff.:Fr.) Fr.

Hypholoma capnoides (Fr. ex Fr.) Kummer

Hypholoma dispersum (Fr.) Quel.

Hypholoma fasciculare (Huds. ex Fr.) Kummer

Inocybe albodisca Pk.

Inocybe calamistrata (Fr.) Gillet 

Inocybe cincinnatula Kühner

P A R T I & I I Appendix 443
Inocybe cookei Bres.

Inocybe eutheles Berk. & Br.

Inocybe fastigiata (Schaeff. ex Fr.) Quel.

Inocybe fuscodisca (Peck) Massae

Inocybe geophylla (Sow. ex Fr.) Kummer

Inocybe lanatodisca Kauffman

Inocybe lanuginosa (Bull. ex Fr.) Kummer 

Inocybe lilacina (Boud.) Kauffman

Inocybe maculata Boud.

Inocybe mixtilis Britz.

Inocybe olympiana A.H. Smith

Inocybe pudica Kühner

Inocybe sororia Kauffman

Inocybe subcarpta Kühner & Boursier

Laccaria amethysteo-occidentalis Mueller 

Laccaria laccata (Scop. ex Fr.) Cke. 

Lactarius affinis Pk.

Lactarius deliciosus (Fr.) S. F. Gray 

Lactarius fragilis var. rubidus Hels. & Smith

Lactarius pseudomucidus Smith & Hesler 

Lactarius rubrilacteus Smith & Hesler

Lactarius subflammeus Smith & Hesler

Lactarius uvidus Fr.

Laetiporus sulphureus (Bull. ex Fr.) Murr. 

Lentinus sulcatus Berk.

Leotia lubrica Fr.

Lepiota clypeolaria (Bull. ex Fr.) Kummer

Lepiota rhacodes Pilat

Leptonia gracilipes Peck

Leptonia parva Peck

Leptonia serrulata (Fr.:Fr.) Kumm.

Leptonia undulatella (Peck) Sacc.

Limacella glioderma (Fr.) R. Maire

Lycoperdon foetidum Bon.

Lycoperdon perlatum Pers.

Lycoperdon pyrifome Schaeff.:Pers. 

Lyophyllum decastes (Fr.) Singer

Marasmius candidus (Bolt.:Fr.) Fr.

Marasmius copelandii Peck

Marasmius umbilicatus Kauffman

Melanoleuca melaleuca (Pers. ex Fr.) Murr.

Mycena acicula (Schaeff. ex Fr.) Kummer

444 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Mycena amabilissima (Peck) Sacc. 

Mycena atroalboides (Peck) Sacc.

Mycena aurantiomarginata (Fr.) Quél.

Mycena capillaris (Schum.:Fr.) Kumm

Mycena citrinomarginata Gillet

Mycena delicatella (Pk.) Smith

Mycena elegantula Peck 

Mycena epipterygia (Fr.) S. F. Gray 

Mycena maculata Karst. 

Mycena murina Murrill 

Mycena occidentalis Murrill

Mycena oregonensis Smith

Mycena pura (Pers. ex Fr.) Kummer

Mycena purpureofusca (Peck) Sacc.

Mycena rorida (Fr.) Quel.

Mycena scabripes (Murrill) Singer

Mycena subcana A.H. Smith

Nattrassia mangiferae

Nidula candida (Pk.) White

Nidula niveotomentosa (Henn.) Lloyd

Nolanea mammosa (L.) Quél. 

Omphalina luteicolor Murrill

Otidea leporina (Fr.) Fuckel 

Paxillus atrotomentosus (Fr.) Fr. 

Peziza badia Pers.

Peziza spp.

Phaeolus schweinitzii (Fr.) Pat.

Phellinus pini (Fr.) Ames

Phellinus weirii

Pholiota astragalina (Fr.) Singer

Pholiota decorata (Murr.) Smith & Kessler 

Pholiota mutabilis (Schaeff. ex Fr.) Kummer

Pholiota terrestris Overholts

Pleurocybella porrigens (Pers. ex Fr.) Singer

Pleurotus ostreatus ( Jacq. ex Fr.) Kummer

Pluteus cervinus (Fr.) Kummer

Polyporus badius (S.F. Gray) Schw.

Polyporus hirtus Quél.

Polyporus volvatus Peck

Psathyrella gracilis (Fr.) Quél.

Psathyrella hydrophila (Fr.) Maire

Psathyrella longistriata (Murre) Smith

P A R T I & I I Appendix 445
Pseudohydnum gelatinosum (Scop. ex Fr.) Karsten

Pseudoplectania melaena (Fr.) Boud.

Ramaria stricta (Fr.) Quél.

Ramariopsis kunzei (Fr.) Donk.

Rhodocybe hirneola (Fr.) Orton

Russula aeruginea Lindl. 

Russula albonigra (Krombh.) Fr. 

Russula alutacea (Pers.:Fr.) Fr.

Russula bicolor Burl.

Russula brevipes Pk.

Russula cremoricolor Earle

Russula cyanoxantha (Schw.) Fr. 

Russula densifolia (Secr.) Gillet

Russula emetica Fr.

Russula fragrantissima Rom.

Russula gracilis Burlingham

Russula placita Burl 

Russula sororia (Fr.) Romell 

Russula xerampelina (Schaeff. ex Secr.) Fr. 

Russulas nigricans Fr. 

Sparassis crispa Wulf:Fr. 

Stereum complicatum (Fr.) Fr.

Strobilurus trullisatus (Murr.) Lennox

Stropharia ambigua (Pk.) Zeller

Stropharia hornemannii (Fr.) Lundell 

Suillus lakei (Murr.) Smith & Thiers

Suillus ponderosus Smith & Thiers

Suillus tomentosus (Kauff.) Singer, Snell, & Dick

Thelephora americana Lloyd

Thelephora palmata Scop.:Fr.

Thelephora terrestris Fr.

Trametes hirsuta (Wulf.:Fr.) Pilat

Trametes versicolor (L. ex Fr.) Pilat

Trichaptum abietinus (Fr.) Donk.

Trichoglossum hirsutum (Fr.) Boudier

Tricholoma flavovirens (Pers. ex Fr.) Lundell 

Tricholoma imbricatum (Fr.:Fr.) Kumm.

Tricholoma sulphureum (Bull.:Fr.) Kumm.

Tricholoma terreum (Schaeff.:Fr.) Kumm.

Tricholomopsis rutilans (Schaeff. ex Fr.) Singer 

Tubaria furfuracea (Pers. ex Fr. Gillet

Tyromyces caesius (Fr.) Murr.

446 AIMing for Healthy Forests: Active, Intentional Management for Multiple Values
Tyromyces chioneus (Fr.) Karsten

Xeromphalina campanella (Bat. ex Fr.) Kuhner & Maire

Xeromphalina fulvipes (Murr.) Smith 

Xylaria hypoxylon (L. ex Hooker) Grev.

a Common names are provided for plants and animals. However, because many fungi do not have common names, 

none are provided for any of the included fungi.

P A R T I & I I Appendix 447

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