United States

Department of

Agriculture

Forest Service

Pacific Northwest

Research Station

General Technical 

Report

PNW-GTR-844

August 2011

Adapting to Climate 

Change at Olympic 

National Forest and 

Olympic National Park
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.

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activities on the basis of race, color, national origin, age, disability, and where applicable, sex, 

marital status, familial status, parental status, religion, sexual orientation, genetic information, 

political beliefs, reprisal, or because all or part of an individual’s income is derived from any 

public assistance program. (Not all prohibited bases apply to all programs.) Persons with 

disabilities who require alternative means for communication of program information (Braille, 

large print, audiotape, etc.) should contact USDA’s TARGET Center at (202) 720-2600 (voice 

and TDD). To file a complaint of discrimination, write USDA, Director, Office of Civil Rights, 

Room 1400 Independence Avenue, SW, Washington, DC 20250-9410 or call (800) 795-3272 

(voice) or (202) 720-6382 (TDD). USDA is an equal opportunity provider and employer.

Editors

Jessica E. Halofsky is a research ecologist, University of Washington, College of the 

Environment, School of Forest Resources, Box 352100, Seattle, WA 98195-2100; David L. 

Peterson is a research biological scientist, U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station, Pacific Wildland Fire Sciences Laboratory, 400 N 

34th St., Suite 201, Seattle, WA 98103; Kathy A. O’Halloran is the natural resources staff 

officer, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 

Black Lake Blvd. SW, Olympia, WA 98512-5623; and Catherine Hawkins Hoffman is the 

Climate Change Adaptation Coordinator, National Park Service Natural Resource Program 

Center, 1201 Oakridge Dr., Fort Collins, CO 80525 (formerly Chief, Natural Resources 

Division, Olympic National Park, Port Angeles, WA). This work was performed under 

cooperative agreement PNW-06-CA-11261987-144. 

Cover

Butterfly photo by Betsy Howell, Forest Service (Olympic NF).

River photo by Jessica Halofsky (University of Washington).

Fish photo courtesy of the National Park Service (Olympic NP).

Forest photo courtesy of the U.S. Forest Service (Olympic NF).
Adapting to Climate 

Change at Olympic 

National Forest and 

Olympic National Park

Jessica E. Halofsky, David L. Peterson, 

Kathy A. O’Halloran, and Catherine Hawkins Hoffman 

Editors

U.S. Department of Agriculture, Forest Service

Pacific Northwest Research Station

Portland, Oregon 

General Technical Report, PNW-GTR-844

August 2011
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Abstract

Halofsky, Jessica E.; Peterson, David L.; O’Halloran, Kathy A.; Hawkins Hoffman, 

Catherine, eds. 2011. Adapting to climate change at Olympic National Forest and 

Olympic National Park. Gen. Tech. Rep. PNW-GTR-844. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 130 p.

Climate change presents a major challenge to natural resource managers both because of 

the magnitude of potential effects of climate change on ecosystem structure, processes, and 

function, and because of the uncertainty associated with those potential ecological effects. 

Concrete ways to adapt to climate change are needed to help natural resource managers take 

the first steps to incorporate climate change into management and take advantage of opportunities to counteract the negative effects of climate change. We began a climate change adaptation case study at Olympic National Forest (ONF) in partnership with Olympic National Park 

(ONP) to determine how to adapt management of federal lands on the Olympic Peninsula, 

Washington, to climate change. The case study began in the summer of 2008 and continued 

for 11⁄2 years. The case study process involved science-based sensitivity assessments, review 

of management activities and constraints, and adaptation workshops in each of four focus 

areas (hydrology and roads, fish, vegetation, and wildlife). The process produced adaptation 

options for ONF and ONP, and illustrated the utility of place-based vulnerability assessment 

and science-management workshops in adapting to climate change. The case study process 

provides an example for other national forests, national parks, and natural resource agencies 

of how federal land management units can collaborate in the initial stages of climate change 

adaptation. Many of the ideas generated through this process can potentially be applied in 

other locations and in other agencies. 

Keywords: Adaptation, climate change, fish habitat management, hydrology, road 

management, science-management partnerships, vegetation management, wildlife habitat 

management.
iv

Summary

In this report, we describe results of the Olympic Climate Change Case Study, a sciencemanagement collaboration initiated to develop climate change adaptation strategies and 

actions for Olympic National Forest (ONF) and Olympic National Park (ONP). The case 

study was one of three parallel climate change adaptation case studies on national forests 

and adjacent national parks in the Western United States as a part of a larger effort, the 

WestWide Climate Initiative. This initiative was created by scientists of the U.S. Forest 

Service to address the urgent need to communicate climate change information to land 

managers and work with them to develop adaptation options. 

For the Olympic Climate Change Case Study, we conducted a vulnerability assessment 

to facilitate development of adaptation strategies and actions for ONF and ONP. The first 

step in the vulnerability assessment process involved a review of available climate model 

projections to determine likely levels of exposure to climate change (degree of deviation 

in temperature and precipitation) on the Olympic Peninsula (chapter 3). In the next step, 

we reviewed relevant literature on effects of climate change and available projections to 

identify likely climate change sensitivities in each of four focus areas on the Olympic 

Peninsula, including hydrology and roads (chapter 4), fish (chapter 5), vegetation (chapter 

6), and wildlife (chapter 7). We worked with regional scientists and specialists to interpret 

available information and apply it more directly to Olympic Peninsula ecosystems. Finally, 

we reviewed current management activities at ONF and ONP and identified management 

constraints to evaluate some aspects of institutional capacity to implement adaptive actions. 

Review of current management activities was done by focus area and is described in the 

chapter for each focus area. 

The vulnerability assessment process set the stage for development of adaptation 

options at the forest and park through science-management workshops (also described in 

the chapter for each focus area). The workshop format gave managers an open forum to 

brainstorm, express initial thoughts and ideas, and vet those ideas among peers. Direct 

engagement of scientists and managers in the workshop format fostered development of 

science-based adaptation strategies. During workshop discussions, managers identified 

general priority actions for adaptation, as well as priorities for species protection, habitat 

protection, and monitoring.

Although interagency partnerships exist elsewhere to address specific natural resource 

issues, the Olympic Climate Change Case Study is an unprecedented example of U.S. Forest Service and National Park Service jointly planning for climate change adaptation. The 

case study process produced specific and tangible ways for ONF and ONP to incorporate 

climate change adaptation strategies into management. A key finding of the assessment was 

that the current general management at both ONF and ONP, with restoration as a primary 

goal, is consistent with managing for resilience to prepare ecosystems for a changing 

climate. However, the effort highlighted some potential issues related to climate change that 

challenge current precepts and management guidelines and helped to identify new potential 

actions and actions that could be increased and reprioritized. 
v

Climate change adaptation requires systematic monitoring and evaluation to detect 

changes and determine the success of adaptive management activities. Staying abreast of 

available information on potential climate change effects is essential to determine additional ways to incorporate climate change adaptation into management. Although further 

effort will be required, the case study described in this report was an essential first step for 

ONF, ONP, and their stakeholders in preparing for climate change on the Olympic Peninsula. 
vi

 Contents

1 Chapter 1: Introduction

Jessica E. Halofsky, David L. Peterson, Kathy A. O’Halloran, and 

Catherine Hawkins Hoffman

3 References

5 Chapter 2: Olympic National Forest and Olympic National Park: 

Biogeographic Setting, Cultural History, and Policy Context

Jessica E. Halofsky, Kathy A. O’Halloran, Catherine Hawkins Hoffman, 

David L. Peterson, and Jacilee Wray

5 The Olympic Peninsula

5 Cultural History of the Olympic Peninsula

7 Olympic National Forest 

8 Olympic National Park

10 Similarities in Management Between Olympic National Forest and 

Olympic National Park

10 References

13 Chapter 3: Future Climate on the Olympic Peninsula: Forest-Relevant 

Climate Scenarios

 Jeremy S. Littell

13 Introduction

13 Emissions Scenarios: A1B (Moderate) and B1 (Low)

14 Pacific Northwest Future Regional Climate

16 Climatic Downscaling: Winter Precipitation and Water Deficit

18 Literature Cited

21 Chapter 4: Climate Change, Hydrology, and Road Management at 

Olympic National Forest and Olympic National Park

Jessica E. Halofsky, William S. Shelmerdine, Robin Stoddard, Robert 

Metzger, Alan F. Hamlet, and Catherine Hawkins Hoffman

21 Potential Effects of Climate Change on Hydrology on the Olympic 

Peninsula

21 Temperature, Snowpack, and Timing of Streamflow

25 Precipitation, Storm Intensity, and Flooding

26 Effects of Changing Hydrology on Physical Watershed Processes

27 Road Management at Olympic National Forest and Olympic National Park

27 Road Management at Olympic National Forest

31 Road Management at Olympic National Park

35 Climate Change Adaptation Strategies and Action Items for Road 

Management at Olympic National Forest and Olympic National Park 

35 Process Used to Develop Adaptation Strategies for Road Management

35 General Adaptation Strategies for Road Management

38 Adaptation Strategies for Road Management Planning and Prioritization at 

Olympic National Forest
vii

39 Adaptation Strategies for Road Operations and Maintenance at Olympic 

National Forest and Olympic National Park

39 Adaptation Strategies for Road Design

40 Challenges and Opportunities in Climate Change Adaptation in Road 

Management

41 Acknowledgments

41 Literature Cited

43 Chapter 5: Climate Change, Fish, and Fish Habitat Management at 

Olympic National Forest and Olympic National Park

Nathan J. Mantua, Robert Metzger, Patrick Crain, Samuel Brenkman, 

and Jessica E. Halofsky

43 Potential Climate Change Effects on Hydrology, Summer Stream 

Temperatures, and Fish on the Olympic Peninsula

43 Summertime Stream Temperature Projections

44 Climate Change Effects on Snowpack and Streamflow

45 Projected Effects of Altered Hydrology on Olympic Peninsula Salmon, 

Steelhead, and Bull Trout

48 Fish Habitat Management at Olympic National Forest and Olympic 

National Park

48 Biogeographic Context

48 Guiding Policies and Legislation

49 Primary Fish Habitat Management Issues and Activities

50 Climate Change Adaptation in Fish and Fish Habitat Management

at Olympic National Forest and Olympic National Park 

50 Process Used in Development of Adaptation Strategies for Fish 

Management

51 Adaptation Strategies and Actions for Hatcheries and Harvest

53 Adaptation Strategies and Actions for Fish Habitat Management

57 Challenges and Future Directions in Adaptation in Fish and Fish Habitat 

Management

57 Acknowledgments

58 Literature Cited

61 Chapter 6: Climate Change and Vegetation Management at Olympic 

National Forest and Olympic National Park

Jessica E. Halofsky, David L. Peterson, Carol Aubry, Christopher 

Dowling, and Steven A. Acker

61 Vegetation on the Olympic Peninsula

61 Potential Climate Change Effects on Vegetation on the Olympic 

Peninsula

63 Paleoecological Records of Climate and Species Distribution

63 Modern Records of Climate, Tree Growth, and Fire

65 Trends With Recent Warming
viii

67 Model Predictions for Future Vegetation Patterns With Climate Change

73 Vegetation Management at Olympic National Forest and Olympic 

National Park

74 Native Plants and Revegetation

75 Exotic Species Management

76 Sensitive and Rare Plants

76 Prescribed Fire, Wildland Fire Use, and Hazardous Fuel Treatment

77 Vegetation Monitoring

77 Forest Thinning Program at Olympic National Forest

79 Genetic Resources Program at Olympic National Forest

80 Adapting Vegetation Management to Climate Change at Olympic National 

Forest and Olympic National Park

80 Process Used to Develop Adaptation Strategies for Vegetation 

Management

80 Key Vegetation Sensitivities With Climate Change on the Olympic 

Peninsula

83 Goals and Priorities for Adaptation in Vegetation Management

83 Adaptation Strategies and Actions for Vegetation Management at Olympic 

National Forest and Olympic National Park

85 Key Questions and Future Directions

85 Acknowledgments

85 Literature Cited

91 Chapter 7: Climate Change, Wildlife Management, and Habitat 

91 Management at Olympic National Forest and Olympic National Park

 Jessica E. Halofsky, Susan Piper, Kurt Aluzas, Betsy Howell, Paul Griffin, 

Patti Happe, Kurt Jenkins, Catherine Hawkins Hoffman, Joshua Lawler, 

Michael Case, and Karen Reagan

91 Potential Climate Change Effects on Wildlife on the Olympic Peninsula

91 Direct Effects of Climate Change on Wildlife

92 Indirect Effects of Climate Change on Wildlife

96 Potential Genetic Responses to Climate Change

97 Potential Climate Change Effects on Olympic Peninsula Habitats

101 Wildlife and Habitat Management at Olympic National Forest and 

Olympic National Park

102 Policy Guidance and Goals

103 Habitat Improvement and Restoration Activities

104 Surveys and Monitoring

105 Adapting Wildlife and Habitat Management to Climate Change at Olympic 

National Forest and Olympic National Park

105 Process Used to Develop Adaptation Strategies for Wildlife and Habitat 

Management
ix

107 Olympic Peninsula Wildlife Species Sensitivity to Climate Change

110 Adaptation Strategies and Actions for Wildlife and Habitat Management at 

Olympic National Forest and Olympic National Park

112 Policy Considerations and Next Steps

114 Acknowledgments

114 Literature Cited

119 Chapter 8: Synthesis and Conclusions

Catherine Hawkins Hoffman, Kathy A. O’Halloran, Jessica E. Halofsky, and 

David L. Peterson

119 Utility of the Adaptation Process

119 Lessons Learned

119 Where Is the Recipe?

119 Timing

119 Scale and Participants

120 Scope

120 How to Deal With Copious New Information

120 Structure for Results

120 The Case for Splitting

121 The Case for Lumping—Synthesis Across Disciplines

121 Making It Real—Incorporate Geospatial Planning

121 Dealing With Uncertainty

122 Rethinking Management Goals

122 Capacity

123 Raising Awareness

123 Themes in Climate Change Adaptation Strategies at Olympic National 

Forest and Olympic National Park

123 Next Steps

124 Acknowledgments

124 Literature Cited

125 English Equivalents

125 Common and Scientific Names 

129 Glossary
x

GENERAL TECHNICAL REPORT PNW-GTR-844

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1

Adapting to Climate Change at Olympic National Forest and Olympic National Park

There is strong and growing scientific evidence for humaninduced global climate change (Pachauri and Reisinger 

2007). Global ecological effects triggered by warming in 

the late part of the 20th century include earlier snowmelt 

and decreased spatial extent of snow and ice (Barnett et al. 

2008, Hamlet et al. 2005, Mote et al. 2005, Pachauri and 

Reisinger 2007), shifts in species distributions (Parmesan 

2006, Parmesan and Yohe 2003, Mote et al. 2005, Root et 

al. 2003), and rising sea levels (Parry et al. 2007). Despite 

current and future greenhouse gas mitigation efforts, 

changes in the climate system will continue owing to 

already elevated concentrations of carbon dioxide in the 

Earth’s atmosphere (Watson and the Core Writing Team 

2001). Thus, climate change adaptation, or “the adjustment 

in ecological, social, or economic systems in response to 

climate stimuli and their effects” (Pachauri and Reisinger 

2007), will be critical in reducing unwanted effects of 

climate change on both ecosystems and society. 

Climate change presents a major challenge to natural 

resource managers because of the magnitude of potential 

effects of climate change on ecosystem structure, process, 

and function, and because of the uncertainty associated with potential ecological effects. Although general 

guidelines exist (e.g., Julius et. al. 2008, Millar et al. 2007) 

to proactively incorporate climate change into planning, 

decisions, and activities, managers require concrete and 

place-based methods to adapt to climate change.

Scientists and managers must work together to develop 

and implement strategies that facilitate adaptation to climate 

change. Resource managers have the skills and local knowledge to incorporate climate change into management.

However, there is an overwhelming amount of climate 

change information to absorb, a steep learning curve with 

Chapter 1: Introduction 

Jessica E. Halofsky, David L. Peterson, Kathy A. O’Halloran, and Catherine Hawkins Hoffman1

1 Jessica E. Halofsky is a research ecologist, University of Washington, College of the Environment, School of Forest Resources, 

Box 352100, Seattle, WA 98195-2100; David L. Peterson is a research biological scientist, U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Research Station, Pacific Wildland Fire Sciences Laboratory, 400 N 34th St., Suite 201, Seattle, WA 

98103; Kathy A. O’Halloran is the natural resources staff officer, U.S. Department of Agriculture, Forest Service, Olympic 

National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; Catherine Hawkins Hoffman is the Climate Change 

Adaptation Coordinator, National Park Service Natural Resource Program Center, 1201 Oakridge Dr., Fort Collins, CO 80525 

(formerly Chief, Natural Resources Division, Olympic National Park, Port Angeles, WA).

climate change science, and little time for learning owing to 

managers’ many responsibilities. Given the relative infancy 

and experimental nature of climate change adaptation strategies, resource managers generally lack specific guidance 

and directives regarding how to incorporate climate change 

into program planning and implementation. Scientists have 

technical knowledge on climate change but often a poor 

understanding of management and regulatory, policy, and 

collaborative social processes for resource planning and 

decisionmaking. Although these two groups of specialists 

share complementary sets of skills and knowledge, a lack 

of formal relationships, and differences in work culture, 

timeframes, and communication styles limit sciencemanagement interactions on climate change issues.

In this report, we describe results of the Olympic 

Climate Change Case Study, a science-management 

collaboration initiated as part of a larger effort called the 

WestWide Climate Initiative (USDA Forest Service 2007). 

Scientists of the U.S. Forest Service created the WestWide 

Climate Initiative to address the urgent need to provide 

climate change information and adaptation tools to land 

managers in the Western United States. As a part of this 

initiative, parallel case studies were conducted to develop 

climate change tools and adaptation options at Olympic 

National Forest (ONF) and Olympic National Park (ONP) 

(Washington); Tahoe National Forest, Inyo National Forest, 

and Devils Postpile National Monument (California); and 

Shoshone National Forest (Wyoming).

The Olympic Climate Change Case Study occurred 

in two phases. The first phase involved education for 

managers at ONF on climate change science and potential 

effects of climate change, and an initial effort to develop 
2

GENERAL TECHNICAL REPORT PNW-GTR-844

adaptation strategies (Littell et al. 2011). The second phase, 

described here, focused on further development of strategies and actions for climate change adaptation. The case 

study began in the summer of 2008 and continued for 11⁄2 

years. The ONP joined with ONF in the second phase of the 

case study because of the proximity of the park and forest, 

similarities in management goals, and the importance of 

collaboration between neighbors in preparing for climate 

change. Although interagency partnerships exist elsewhere 

to address specific natural resource issues, this collaborative 

effort is unprecedented in development of climate change 

adaptation strategies and actions for a large landscape. 

The second phase of the Olympic Climate Change 

Case Study developed adaptation strategies and actions in 

four focus areas identified by ONF and ONP managers as 

being most important: hydrology and roads, fish, vegetation, and wildlife. To develop adaptation actions for each 

focus area, we conducted a vulnerability assessment, or an 

assessment of the degree to which geophysical, biological, 

and socioeconomic systems are susceptible to, and unable to 

cope with, unwanted impacts of climate change (Parry et al. 

2007). Vulnerability is a function of system exposure, its 

sensitivity, and its adaptive capacity (Gallopín 2006, Parry 

et al. 2007). In a climate change context, exposure can be 

thought of as the degree, duration, or extent of deviation 

in climate to which a system is exposed. Sensitivity is the 

degree to which a system is affected, either positively or 

negatively and directly or indirectly, by climate-related 

stimuli (Parry et al. 2007). Adaptive capacity is the ability 

of a system to adjust to climate change (including climate 

variability and extremes), to moderate potential damages, 

to take advantage of opportunities, or to cope with the 

consequences (Parry et al. 2007). 

To determine likely levels of exposure to climate 

change on the Olympic Peninsula, we reviewed global 

climate model projections included in the University of 

Washington Climate Impacts Group Washington State 

Assessment (Mote and Salathé 2010) (see chapter 3 for 

further detail). Then, to assess other aspects of climate 

change vulnerability and develop adaptation options, for 

each focus area, we used a three-part process that involved: 

• An assessment of climate change sensitivity through a 

topical literature review and review of available climate 

change impact model output, incorporating information 

directly applicable to the Olympic Peninsula whenever 

possible. Sometimes, scientists summarized bestavailable information in presentations to managers, and 

scientists and managers worked together to interpret 

and apply it to Olympic Peninsula ecosystems.

• An assessment of the capacity of ONF and ONP to 

adapt to climate change through review of current 

management practices and potential regulatory and 

institutional constraints.

• Development of adaptation strategies through sciencemanagement workshops. The results of the vulnerability assessment provided the starting point for facilitated 

science-management dialog on possible adaptation 

strategies in each focus area. The workshop format 

provided opportunities to transfer information and 

facilitate discussions between managers and scientists.

In all steps of the case study process, scientists and 

managers worked together to gather and refine information 

to identify climate change vulnerabilities and develop adaptation options for ONF and ONP. For consistency across 

focus areas, two scientists from the Forest Service Pacific 

Northwest Research Station and the natural resource staff 

supervisors from ONF and ONP participated in and guided 

the entire process. Participants in each focus area included 

forest and park staff specialists, including silviculturists, 

forest geneticists, botanists, wildlife biologists, engineers, 

fish biologists, and hydrologists. For each focus area, scientists from the University of Washington Climate Impacts 

Group and Forest Service scientists provided presentations 

and participated in discussions of adaptation options. Both 

the hydrology and roads, and vegetation workshops were 

limited to forest and park specialists and scientists with 

specialized knowledge in the focus area because of the need 

for progress within a specific timeframe, and for continuity 

and commitment to the process over many months, in addition to the complicated scheduling, logistics, and orchestration of a large-group planning process. However, the 

wildlife workshops included specialists from other natural 
3

Adapting to Climate Change at Olympic National Forest and Olympic National Park

resource organizations, including the Washington Department of Natural Resources, the U.S. Geological Survey, and 

U.S. Fish and Wildlife Service, to take advantage of their 

specialized knowledge of wildlife on the peninsula and 

interest in climate change. A science-focused fish workshop 

included over 100 participants from a variety of state and 

federal natural resource agencies, watershed organizations, 

and tribes. The fish workshop was opened to a broader 

audience because fish (particularly salmonids) are one of 

the widest ranging, multijurisdictional organisms inhabiting the peninsula. A critical next step will be to work with 

these and other partners in climate change adaptation on the 

peninsula. 

During workshop discussions, ONF and ONP identified 

general priority actions for adaptation, as well as priorities 

for species protection, habitat protection, and monitoring. 

In developing these adaptation strategies, the goal was to 

identify no-regrets strategies and actions that are likely to 

produce favorable outcomes, are compatible with current 

management objectives, and are adaptable through time. For 

the purposes of the workshops, it was assumed that there 

will be no changes in policy mandates (e.g., land allocation designations, Endangered Species Act ([ESA 1973]) 

listings, or directives in the Northwest Forest Plan) over 

the next 5 years. These objectives and constraints yielded 

realistic and tangible adaptation strategies and actions for 

ONF and ONP. 

References

Barnett, T.P.; Pierce, D.W.; Hidalgo, H.G. [et al.]. 2008.

Human-induced changes in the hydrology of the western 

United States. Science. 19: 1080–1083.

Endangered Species Act of 1973 [ESA]; 16 U.S.C. 

1531–1536, 1538–1540.

Gallopín, G.C. 2006. Linkages between vulnerability, 

resilience, and adaptive capacity. Global Environmental 

Change. 16: 293–303. 

Hamlet, A.F.; Mote, P.W.; Clark, M.P.; Lettenmaier, D.P. 

2005. Effects of temperature and precipitation variability 

on snowpack trends in the Western U.S. Journal of 

Climate. 18: 4545–4561.

Julius, S.H.; West, J.M., eds. 2008. Preliminary review 

of adaptation options for climate-sensitive ecosystems 

and resources: a report by the U.S. Climate Change 

Science Program and the Subcommittee on Climate 

Change Research. Washington, DC: U.S. Environmental 

Protection Agency. 873 p.

Littell, J.S.; Peterson, D.L.; Millar, C.I.; O’Halloran, 

K. 2011. U.S. national forests adapt to climate change 

through science-management partnerships. Climatic 

Change. DOI 10.1007/s 10584-011-0066-0.

Millar, C.I.; Stephenson, N.L.; Stephens, S.L. 2007.

Climate change and forests of the future: managing in 

the face of uncertainty. Ecological Applications. 

17: 2145–2151.

Mote, P.W.; Hamlet, A.F.; Clark, M.; Lettenmaier, D.P. 

2005. Declining mountain snowpack in western North 

America. Bulletin of the American Meteorological 

Society. 86: 39–49.

Mote, P.W.; Salathé, E.P., Jr. 2010. Future climate in the 

Pacific Northwest. Climatic Change.102: 29–50.

Pachauri, R.K.; Reisinger, A., eds. 2007. Climate change 

2007: synthesis report; a contribution of working groups 

I, II, and III to the fourth assessment report of the 

Intergovernmental Panel on Climate Change. Geneva, 

Switzerland: Intergovernmental Panel on Climate 

Change. 104 p.

Parmesan, C. 2006. Ecological and evolutionary responses 

to recent climate change. Annual Review of Ecology, 

Evolution, and Systematics. 37: 637–669. 

Parmesan, C.; Yohe, G. 2003. A globally coherent 

fingerprint of climate change impacts across natural 

systems. Nature. 421: 37–42.

Parry, M.L.; Canzianai, O.F.; Palutikof, J.P. [et al.], 

eds. 2007. Climate change 2007: impacts, adaptation, 

and vulnerability; contribution of working group II to 

the fourth assessment report of the Intergovernmental 

Panel on Climate Change. Cambridge, United Kingdom: 

Cambridge University Press. 976 p.
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GENERAL TECHNICAL REPORT PNW-GTR-844

Root, T.L.; Price, J.T.; Hall, K.R. [et al.]. 2003. 

Fingerprints of global warming on wild animals and 

plants. Nature. 421: 57–60.

U.S. Department of Agriculture, Forest Service [USDA 

FS]. 2007. Westwide Climate Initiative: a researchmanagement partnership. http://www.fs.fed.us/psw/

topics/climate_change/pdf/Apr07hill_westsideCI.pdf. 

(12 March 2010). 

Watson, R.T. the Core Writing Team, eds. 2001. Climate 

change 2001: synthesis report; a contribution of working 

groups I, II, and III to the third assessment report 

of the Intergovernmental Panel on Climate Change. 

Cambridge, United Kingdom: Cambridge University 

Press. 398 p. 
5

Adapting to Climate Change at Olympic National Forest and Olympic National Park

The Olympic Peninsula

Located in the northwestern portion of Washington state, 

USA, the Olympic Peninsula comprises an area of 16 800 

km2 (fig. 2.1). Bounding the peninsula is the Pacific Ocean 

to the west, the Strait of Juan de Fuca to the north, and 

Puget Sound and Hood Canal to the east. Elevation on the 

peninsula ranges from sea level to 2427 m at Mount Olympus, the highest peak of the Olympic Mountains, which 

dominate the central portion of the peninsula. The steep and 

dissected topography in the central portion of the peninsula 

results in temperature and precipitation gradients and varied 

climatic conditions (Peterson et al. 1997). A wet and humid 

maritime climate characterizes the western, coastal side of 

the peninsula, which receives 300 to 500 cm of precipitation per year depending on location, while the crest of the 

Olympic Mountains receives >600 cm of precipitation per 

year, making it the wettest location in the coterminous 

United States (Peterson et al. 1997). In contrast, the northeastern portion of the peninsula is characterized by a drier, 

more continental climate owing to the rainshadow effect 

of the Olympic Mountains (and prevailing winds from the 

southwest during the winter). Rainfall in the northeastern 

portion of the peninsula is as low as 50 cm per year at lower 

elevations (Henderson et al. 1989). Most precipitation falls 

between October and March, and winter precipitation falls 

mainly as rain below 300 m, as rain and snow between 300 

m and 750 m, and as snow above 750 m. Snow at higher 

elevations persists through the early part of summer. 

Varied climatic conditions on the peninsula result in 

diverse ecological communities. Vegetation assemblages 

on the peninsula include temperate rain forests, mixedconifer forests, prairies, alpine tundra, subalpine parklands, 

wetlands, rivers, streams, and mountain lakes. There are 

1,480 native vascular plant species (Buckingham et al. 

1995) on the peninsula, including eight endemic species. 

Several endemic animal species also inhabit the peninsula, 

including the Olympic marmot, the Olympic pocket gopher, 

and the Olympic torrent salamander (See Common and 

Scientific names). 

Land ownership on the peninsula is a mix of federal, 

state, tribal, and private lands (fig. 2.1). Olympic National 

Park (ONP) occupies the core of the peninsula and includes 

much of the higher elevation portion. Olympic National 

Forest (ONF) surrounds the park. The forest and park cover 

about one-third of the peninsula. 

Cultural History of the Olympic Peninsula

The Olympic Peninsula has a rich cultural history involving extensive interaction between native peoples and their 

environment. Prior to what European Americans call the 

historic period (less than 200 years before present), there 

were about 10,000 people living on the Olympic Peninsula, 

the ancestors of the tribes here today: the Elwha Klallam, 

Jamestown S’Klallam, Port Gamble S’Klallam, Quinault, 

Hoh, Quileute, Makah, Queets, and Skokomish (Wray 

2002). The tribes of the Olympic Peninsula maintain 

close ties to all of their ancestral lands and share concern 

for resource protection. They are an integral part of the 

ecosystem, as their traditional practices included land 

management, such as maintaining prairies by burning them 

to increase edible and medicinal plant populations. 

Chapter 2: Olympic National Forest and Olympic National Park: 

Biogeographic Setting, Cultural History, and Policy Context

Jessica E. Halofsky, Kathy A. O’Halloran, Catherine Hawkins Hoffman, David L. Peterson, and Jacilee Wray1

1 Jessica E. Halofsky is a research ecologist, University of Washington, College of the Environment, School of Forest Resources, 

Box 352100, Seattle, WA 98195-2100; Kathy A. O’Halloran is the natural resources staff officer, U.S. Department of Agriculture, 

Forest Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; Catherine Hawkins Hoffman

is the Climate Change Adaptation Coordinator, National Park Service Natural Resource Program Center, 1201 Oakridge Dr., Fort 

Collins, CO 80525 (formerly Chief, Natural Resources Division, Olympic National Park, Port Angeles, WA); David L. Peterson

is a research biological scientist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific 

Wildland Fire Sciences Laboratory, 400 N 34th St., Suite 201, Seattle, WA 98103; Jacilee Wray is the park anthropologist, Olympic 

National Park, 600 East Park Ave., Port Angeles, WA 98362.
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GENERAL TECHNICAL REPORT PNW-GTR-844

In 1854, Governor Issac Stevens, who was also 

Superintendent of Indian Affairs in Washington Territory, 

began treaty negotiations to unite the numerous bands of 

Indians into tribes and to extinguish title to their lands 

for settlement by U.S. citizens. The treaties established 

formal relationships between the tribes as sovereigns and 

the United States and established the Quinault, Skokomish, 

and Makah reservations. The Quileute and Hoh reservations were established by Executive order and the three 

Figure 2.1—Location of and land ownership on the Olympic Peninsula.
7

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Klallam reservations by Congress. Tribal reservation lands 

on the peninsula comprise over 89 000 ha, ranging from 

the Quinault Reservation, encompassing 86 000 ha, to the 

Jamestown S’Klallam Reservation, with only 2 ha. 

The peninsula treaties that ceded the land now within 

ONP include the Treaty of Point No Point 1855 (Skokomish 

and Klallam), Treaty of Neah Bay 1855 (Makah), and Treaty 

of Olympia 1856 (Quinault, Quileute, and Hoh). The treaties 

specify that the tribes have the right to fish at “usual and 

accustomed grounds and stations... in common with all citizens... together with the privilege of hunting and gathering 

roots and berries on open and unclaimed lands.” In 1974, 

Federal District Court Judge George Boldt found that the 

tribes were guaranteed an equal share or half of the sustainable harvest of anadromous fish in U.S. v. Washington. He 

also found that the treaties were “not a grant of rights to the 

Indians, but a grant of rights from them, and a reservation 

of those not granted” [United States v. State of Washington 

384 F. Supp. 312 (1974):323]. In other words, these were not 

rights given to them, but rights they always had—from time 

immemorial. 

The relationship between the first people and the 

Olympic Peninsula is recounted in origin legends and 

mythic events that explain both the creation of the landscape and peoples’ relationship to it. These legends depict 

a strong reliance upon waterways, forests, and valleys for 

the acquisition of vital resources, and detailed descriptions 

of travel into the mountains for pleasure, social interchange 

such as marriage, and spiritual pursuits [Wray 2002]. 

Trails were used where canoes could not go, following 

the river drainages to the open meadows and mountain 

ridgelines. Trails crossed the mountains between the Hoh 

and the Elwha Rivers and from the Quileute to the Pysht 

and the Hoko (Gibbs 1877). Other trails led from Hood 

Canal to Grays Harbor, and crossed the Olympics from 

the Skokomish and Dosewallips River drainages to the 

Quinault. Many of the trail routes are the same routes used 

today by hikers in the park and forest. 

The remains of stone tool manufacture, or lithics, have 

been documented in the Olympic Mountains and surrounding foothills by archeologists. These tools were used for 

hunting, butchering, and plant processing. In 1993, portions 

of a woven cedar basket—part of a pack basket used as a 

backpack—were found in the alpine reaches of ONP. This 

discovery provides additional evidence of high-country 

habitation. The basket has been radiocarbon dated to be 

about 2,880 years old. 

Maritime archeological village sites on the Pacific 

coast, Strait of Juan de Fuca, and Hood Canal had economies that included intertidal gathering, fishing, sealing, and 

whaling, dating back thousands of years. Animal remains, 

along with stone and wood artifacts, indicate the presence 

of an “Early Maritime” culture on the Olympic Peninsula 

about 3,000 years ago (Bergland 1983). This culture relied 

on salmon and shellfish, which had likely increased in 

abundance in response to stabilization of sea level and 

increased precipitation during that time period (Henderson 

et al. 1989). 

Native peoples of the Olympic Peninsula used native 

plant materials extensively (Gunther 1945, Norton 1979, as 

cited in Henderson et al. 1989). Western redcedar was used 

for a variety of purposes, including cedar plank houses, 

canoes, fishing tools, cradles, paddles, and arrowshafts 

(Henderson et al. 1989). The bark of western redcedar 

was also used to make clothing, baskets, mats, and eating utensils, among other objects (Gunther 1945). Other 

plants, such as camas, bracken fern, salmonberry, salal, and 

huckleberries, provided important food sources (Henderson 

et al. 1989). Prairies were regularly burned to maintain and 

cultivate camas and other food plants (Norton 1979). 

Native plants were also used for medicine and other 

purposes. For example, stinging nettle was used for medicine and rope (Henderson et al. 1989). Cattail and beargrass 

were used in basketry. Sitka spruce roots were also used for 

nets and cordage, and spruce pitch, limbs, bark, and wood 

were also used (Henderson et al. 1989). 

Olympic National Forest 

Created in 1907, ONF encompasses an area of 256 440 ha, 

15 percent of which is federally designated wilderness. The 

mission of the Forest Service, and thus ONF, is “to sustain 

the health, diversity, and productivity of the Nation’s forest 

and grasslands to meet the needs of present and future 

generations” (USDA FS 2007). Timber production and 
8

GENERAL TECHNICAL REPORT PNW-GTR-844

fresh water were historically the most valued ecosystem 

services provided by ONF. Timber harvest activities began 

on ONF in the 1920s. Until the 1990s, timber management 

generally consisted of clearcutting, broadcast burning, and 

tree replanting. These management practices resulted in the 

conversion of over one-third of ONF into relatively young 

even-aged forests. In addition, over 3500 km of forest roads 

built for timber harvest remain on the forest road network. 

The 1994 Northwest Forest Plan (NWFP) (USDA and 

USDI 1994) and a change in Forest Service agency management policy led to a movement toward ecosystem management at ONF. Ecosystem management from a Forest Service 

perspective has four main components including protecting 

ecosystems, restoring deteriorated ecosystems, providing 

multiple-use benefits for people within the capabilities of 

ecosystems, and ensuring organizational effectiveness. The 

NWFP also mandates management for ecological priorities, 

mainly the protection, enhancement, and acceleration of 

late-successional forest conditions. At ONF, a major land 

allocation under the NWFP is late-successional reserve 

(LSR), the goal of which is to maintain late-successional 

and old-growth forest ecosystems. The LSRs are designed 

primarily to serve as habitat for late-successional and oldgrowth-related species, including the northern spotted owl. 

Olympic National Forest is focused on: 

• Managing for native biodiversity and promoting the 

development of late-successional forests 

• Restoring and protecting aquatic ecosystems from the 

impacts of an aging road infrastructure

• Managing for individual threatened and endangered 

species as defined by the Endangered Species Act 

(ESA) (ESA 1973) and related policies

Because of this focus on ecological restoration, forest 

personnel consider ONF to be a “restoration forest.” 

Besides the ESA, other federal statutes guide current 

management activities at ONF, including the National 

Forest Management Act (NFMA) (NFMA 1976) and the 

National Environmental Policy Act (NEPA) (NEPA 1969). 

The NFMA imposes directives on national forest planning 

and activities. The NEPA requires all federal government 

agencies to conduct environmental analyses and prepare 

environmental documents (environmental assessments or 

environmental impact statements [EIS]) that assess and 

disclose the environmental impacts of proposed actions.

The ONF land and resource management plan (LRMP) 

(as amended by the NWFP; USDA FS 1990) guides management activities at ONF and is revised every 10 years. A 

key component of the LRMP is the aquatic conservation 

strategy (ACS), which includes eight objectives for maintaining and restoring watershed processes and functions. To 

be consistent with the LRMP and the ACS, all management 

activities at ONF must maintain or help restore watershed 

conditions. 

The ONF also has a forest strategic plan that integrates 

aquatics, wildlife, silviculture, and fire, helping to identify 

priority areas for management activities such as habitat 

restoration, road decommissioning, forest thinning, and fuel 

reduction treatments. Factors such as habitat improvement 

potential (specifically for threatened and endangered species 

and important charismatic species such as Roosevelt elk), 

economic viability of activities, and existing priorities and 

land allocation restrictions determine priority actions. 

The ONF and the Forest Service in general are just 

beginning to address climate change and adaptation to 

climate change. In October 2008, the Forest Service issued 

the Forest Service Strategic Framework for Responding to 

Climate Change (USDA FS 2008), which identified climate 

change adaptation as a key goal for the agency and recommended integrating climate change considerations into 

agency-wide policies and program guidance. The agency 

also issued national guidance on how climate change can 

be incorporated in LMRP revision and analyses of projects. 

Further guidance for adaptation on national forests is in 

development at this writing. 

Olympic National Park

Created in 1938, ONP covers 373 384 ha on the Olympic 

Peninsula. The park includes both the central, mountainous 

portion of the Olympic Peninsula, as well as a strip more 

than 110 km long on the Pacific coast. In 1988, the U.S. 

Congress designated over 95 percent of the park as a wilderness area. Much of the park is in relatively pristine condition, although effects of past human activities are evident 

and persistent in some areas. 
9

Adapting to Climate Change at Olympic National Forest and Olympic National Park

The foundation for National Park Service (NPS) policies governing the management at ONP is the 1916 Organic 

Act, which established an NPS with the purpose to “conserve the scenery and the natural and historic objects and 

the wild life therein and to provide for the enjoyment of the 

same in such manner and by such means as will leave them 

unimpaired for the enjoyment of future generations” (NPS 

1916). The fundamental purpose of the NPS is to conserve 

park resources and values and to provide for enjoyment of 

parks while avoiding or minimizing adverse impacts. Management within parks focuses on preserving physical and 

biological processes and preserving the “natural abundance, 

diversity, and genetic and ecological integrity of the plant 

and animal species native to those ecosystems” (NPS 2006). 

The mandate of the NPS requires that parks both 

conserve natural resources and provide for public enjoyment, although the Redwoods Act (1978) clarified that 

protecting resources takes precedence over providing for 

the enjoyment of the public. Nevertheless, this dual mandate 

entails careful management to avoid conflicts between the 

two goals. Several other statutes such as the NPS General 

Authorities Act (NPS 1970), Clean Air Act (1970), ESA 

(1973), NEPA (1969), Wilderness Act (1964), and Wild and 

Scenic Rivers Act (1968) constitute additional directives for 

park management. Management policies of the NPS (2006) 

provide a stewardship framework and broad guidance to 

park managers. Individual parks develop long-term management plans and other implementation plans that describe 

specific management objectives. 

The ONP General Management Plan (NPS 2008) 

established a vision for managing ONP for the next 15 to 

20 years and aims to protect natural and cultural resources 

while improving visitor experiences. The plan designated 

management zones within the park and established desired 

resource conditions. The plan also established fundamental 

objectives including maintaining access to existing developed areas, trails, campgrounds, and facilities; seeking 

additional partnerships to help provide better visitor access 

and enjoyment and protection of sensitive resources; 

making boundary adjustments through purchases or land 

exchanges to incorporate sensitive resource areas within the 

park (e.g., fish habitat, wetlands); and providing continued 

protection of wilderness resources and cultural resources 

within wilderness. The public participated in the development of this plan. 

Other park plans guide management practices, including the ONP backcountry management plan, the fire 

management plan, and the wilderness management plan 

(to be developed beginning fall 2010). Besides regulations 

found in the Code of Federal Regulations (36CFR part 7.28), 

the ONP superintendant’s compendium establishes regulations that are specific to ONP.

Like ONF, ONP is subject to NEPA. As part of NEPA 

analyses, park managers evaluate management actions 

within the park to determine their potential effect on ONP 

resources, select the action that will meet park management 

needs with the least impacts, and ensure that no activities 

will result in impairment. Depending on the nature of the 

activity, compliance may be relatively informal or may 

require an EIS under NEPA. 

Similar to the Forest Service, the NPS is just beginning 

to address climate change in agency policy and directives. 

The U.S. Department of the Interior (DOI) issued Secretarial Order No. 3226 directing bureaus, including the NPS, 

to “provide leadership by developing timely responses to 

emerging climate change issues.” The secretarial order 

requires agencies in the DOI to consider potential impacts 

of climate change in planning, setting priorities for research, 

and making decisions affecting resources. The order also 

calls on DOI agencies to review existing programs and 

policies to identify potential climate change impacts on 

areas of responsibility and recommend actions in response 

to potential impacts. 

At the agency level, NPS management policies 

(NPS 2006) refer to potential effects of climate change 

on resources and call for parks to gather and maintain 

climate data for reference and to educate visitors about 

climate change. Future management directives may consider climate change responses across all aspects of park 

planning and operations. The NPS Pacific West Region, 

which includes ONP, is developing mitigation strategies 

in response to a regional directive that calls on all parks 

in the region to aim to become carbon neutral. Park planning specialists are developing guidance to include climate 
10

GENERAL TECHNICAL REPORT PNW-GTR-844

change in general management plans and other planning 

documents, as well as draft adaptation concepts for local 

park units in the Pacific West Region.

Similarities in Management Between 

Olympic National Forest and Olympic 

National Park

Although differences in policy exist for management at 

ONF and ONP, similarities in management objectives exist. 

Crosscutting statutes such as the ESA (1973), NEPA (1969), 

Clean Air Act (1970), and Clean Water Act (1977) apply to 

all management activities for both entities. They also have 

similar policy goals for preservation of biodiversity and 

native gene pools. Both ONF and ONP practice ecosystem 

management focused on maintaining ecosystem process and 

function and use restoration as a tool to maintain process 

and function. Policies applied to the wilderness areas of 

the forest and park are very similar. In addition, recreation 

and benefit to society are key functions of both ONP and 

ONF. These similarities in management objectives provide 

a consistent context for how the forest and park adapt to 

climate change. 

References

Bergland, E.O. 1983. Prehistory and ethnography of 

Olympic National Park. Seattle: National Park Service. 

89 p.

Buckingham, N.M.; Schreiner, E.G.; Kaye, T.N. [et al.]. 

1995. Flora of the Olympic Peninsula. Seattle: Northwest 

Interpretive Association. 199 p.

Clean Air Act of 1970, as amended August 1977; 42 

U.S.C. s/s 7401 et seq. 

Clean Water Act of 1977; 33 U.S.C. 1251–1387.

Endangered Species Act of 1973 [ESA]; 16 U.S.C. 

1531–1536, 1538–1540.

Gibbs, G. 1877. [reprinted 1970.] Tribes of western 

Washington and northwestern Oregon. Contributions 

to North American Ethnology. In: Powell, J.W., ed. 

Washington: U.S. Geographical and Geological Survey 

of the Rocky Mountain Region. 1: 157–361.

Gunther, E. 1945. Ethnobotany of western Washington. 

University of Washington Publications in Anthropology. 

10(1). Seattle: University of Washington. 71 p. 

Henderson, J.A.; Peter, P.H.; Lesher, R.D.; Shaw, 

D.C. 1989. Forested plant associations of the Olympic 

National Forest. Ecol. Tech. Pap. R6-ECOL-TP-001-88. 

Olympia, WA: U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Region. 502 p. http://

www.reo.gov/ecoshare/publications/documents/

FPAOlympicNF.pdf. (9 February 2010).

National Environmental Policy Act of 1969 [NEPA]; 42 

U.S.C. 4321 et seq.

National Forest Management Act of 1976 [NFMA]; Act 

of October 22, 1976; 16 U.S.C. 1600.

National Park Service [NPS]. 2006. Management policies 

2006. Washington, DC: U.S. Government Printing 

Office. 179 p. http://www.nps.gov/policy/MP2006.pdf. 

(9 February 2010).

National Park Service [NPS]. 2008. Olympic National 

Park general management plan. Port Angeles, WA: 

Olympic National Park. http://parkplanning.nps.gov/

document.cfm?parkID=329&projectId=10233&document

ID=22448. (9 February 2010).

National Park Service General Authorities Act of 1970 

[NPS]; 1970.84 Stat. 825.

National Park Service Organic Act of 1916 [NPS]; 39 

Stat. 535; 16 U.S.C. 1–4. 

Norton, H.H. 1979. The association between anthropogenic 

prairies and important food plants in western Washington. 

Northwest Anthropological Research Notes. 18: 175–200.

Peterson, D.L.; Schreiner, E.G.; Buckingham, N.M. 

1997. Gradients, vegetation, and climate: spatial and 

temporal dynamics in mountains. Global Ecology and 

Biogeography Letters. 6: 7–17.

Redwoods Act of 1978; 16 U.S.C. §§ 1, 1a-1, Public Law 

No. 95–250.
11

Adapting to Climate Change at Olympic National Forest and Olympic National Park

U.S. Department of Agriculture, Forest Service [USDA 

FS]. 1990. Land and resource management plan for 

Olympic National Forest. Washington, DC: U.S. 

Government Printing Office. 370 p. 

U.S. Department of Agriculture, Forest Service [USDA 

FS]. 2007. USDA Forest Service strategic plan FY 2007–

2012. FS-880, Washington, DC. http://www.fs.fed.us/

publications/strategic/fs-sp-fy07-12.pdf. (9 February 

2010).

U.S. Department of Agriculture, Forest Service [USDA 

FS]. 2008. Forest Service strategic framework for 

responding to climate change, version 1.0. http://www.

fs.fed.us/climatechange/documents/strategic-frameworkclimate-change-1-0.pdf. (12 February 2010).

U.S. Department of Agriculture, Forest Service; 

U.S. Department of the Interior, Bureau of Land 

Management [USDA and USDI]. 1994. Record of 

decision for amendments to Forest Service and Bureau 

of Land Management planning documents within the 

range of the northern spotted owl. [Place of publication 

unknown]. 74 p. [plus attachment A: standards and 

guidelines]. 

Wild and Scenic Rivers Act of 1968; 16 U.S.C. 1271 et 

seq.

Wilderness Act of 1964; 16 U.S.C. 1121 (note), 1131–1136.

Wray, J., ed. 2002. Native peoples of the Olympic 

Peninsula: who we are. Norman, OK: University of 

Oklahoma Press. 185 p.
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13

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Introduction

Adaptation to climate change in forest ecosystems requires 

a robust estimate (or, in the case of substantial uncertainty, 

multiple estimates) of future climate to use in planning and 

scenario development. In this section, I borrow heavily 

from the Washington Climate Change Impacts Assessment (WACCIA) by the University of Washington Climate 

Impacts Group (Littell et al. 2010), the chapter on future 

Pacific Northwest Climate (Mote and Salathé 2010), the 

chapter on regional dynamic climate modeling (Salathé 

et al. 2010), and the chapter on future hydrologic regimes 

(Elsner et al. 2010). I first describe emissions scenarios 

used to constrain the climate models used in this study, 

then summarize findings on regional climate in the Pacific 

Northwest and some of the subregional consequences of 

those climate changes for variables more closely related to 

forest ecosystems (see box 3.1 for summary).

Emissions Scenarios: A1B (Moderate) 

and B1 (Low)

To develop plausible estimates of the future climate of the 

Pacific Northwest, physically based global climate models 

(GCMs) that incorporate key elements of the climate system 

(e.g., ocean, atmosphere, cryosphere [snow and ice], and 

land surface) must be used to project future conditions 

based on known climate dynamics and changes in the climate forcing factors. The primary forcings likely to affect 

changes in climate the most in the 21st century are future 

emissions of greenhouse gases (which increase the heattrapping capability of the atmosphere, causing warming) 

and sulfate aerosols (which reflect sunlight and also promote 

cloud formation, causing local cooling). 

Under the direction of the Intergovernmental Panel on 

Climate Change (IPCC), over 40 emissions scenarios have 

been published in the Special Report on Emissions Scenarios (SRES) (Nakićenović and Swart 2000). These scenarios 

have widely varying assumptions about future socioeconomic changes and the resulting changes in greenhouse gas 

(including carbon dioxide) and aerosol emissions, and represent one constraint on future climate uncertainty. Three 

Chapter 3: Future Climate on the Olympic Peninsula: 

Forest-Relevant Climate Scenarios

Jeremy S. Littell1

Box 3.1—Summary of projected climate change 

effects in the Pacific Northwest and on the 

Olympic Peninsula.

• The Washington Climate Change Impacts Assessment, conducted by the University of Washington 

Climate Impacts Group, provided detailed information on potential climate changes in the Pacific 

Northwest and on the Olympic Peninsula

• Climate models project increases in annual average 

temperature of +0.6 °C to +1.9 °C by the 2020s; +0.9 

°C to +2.9 °C by the 2040s; and +1.6 °C to +5.4 °C by 

the 2080s for the Pacific Northwest.

• Warming is expected to occur during all seasons, 

with most models projecting the largest temperature 

increases in summer.

• Projected changes in annual precipitation in the 

Pacific Northwest differ considerably between 

models, but averaged over all models are small 

(+1 to +2 percent).

• Ensemble means of models for precipitation suggest 

wetter winters (+3.3 percent in the 2040s, +7.6 percent 

in the 2080s) and drier summers (-8.5 percent in the 

2040s, -12.8 percent in the 2080s).

• Summer potential evapotranspiration (one component 

of water balance and closely related to fuel moisture 

and tree stress) is expected to increase by 5 to 18 

mm by the 2040s, with much of the largest increases 

in lower elevation forests in the northeastern portion 

of the peninsula.

• Winter precipitation on the Olympic Peninsula is 

likely to increase by 4.5 to 5 percent, on average and 

depending on location.

• In addition to increased precipitation quantity, 

regional climate models show significant increases 

in the intensity of winter precipitation in the western 

portion of the Olympic Peninsula.

1 Jeremy S. Littell is a research scientist, University of Washington, Climate Impacts Group.
14

GENERAL TECHNICAL REPORT PNW-GTR-844

of these SRES scenarios were commonly chosen for forcing 

GCMs used in the IPCC Fourth Assessment Report: B1, 

A1B, and A2. The climate forcing of all scenarios is similar 

until the 2020s because of a long lifetime of coal-fired 

electric powerplants and of the major greenhouse gases. Of 

these three scenarios, A2 produces the highest emissions by 

the end of the century, but before mid-century, none of the 

scenarios is consistently the highest. Because more modeling groups use A1B than A2, and because the focus for this 

study was on mid-century change, A1B was used as the 

higher emissions scenario and B1 as the low emissions scenario for analysis of 21st-century Pacific Northwest climate. 

Though B1 is the lowest of the IPCC illustrative scenarios, 

it still produces changes in climate that many scientists call 

“dangerous” (Schellnhuber et al. 2006). At the high end, 

scenario A1FI results in even higher climate forcing by 2100 

than A1B. Mid-2000s global emissions of carbon dioxide 

exceeded even the A1FI scenario (Raupach et al. 2007). 

Whether these exceedingly high emissions will continue 

into the future is uncertain, but in any case, the projections 

described here are potentially conservative. 

Pacific Northwest Future Regional Climate

Mote and Salathé (2010) used 20 different climate models 

to explore the consequences of two different greenhouse 

gas emissions scenarios for the Pacific Northwest. All of 

the models indicate that the future climate will be warmer 

than the past (fig. 3.1) and, together, they suggest that Pacific 

Northwest warming rates will be greater in the 21st century 

than those observed in the 20th century. All changes below 

are relative to the period 1970–1999, and all are regionally averaged changes that apply to the Pacific Northwest. 

Climate models project increases in annual average temperature of +1.1 °C, range +0.6 °C to +1.9 °C by the 2020s; 

+1.8 °C, range +0.9 °C to +2.9 °C by the 2040s; and +3.0 °C, 

range +1.6 °C to +5.4 °C by the 2080s. Climate models are 

Figure 3.1—Simulated temperature change for the 20th- and 21st-century global climate model simulations for 

the Pacific Northwest region. The black curve is the weighted average of all models during the 20th century. 

The colored curves are the weighted average of all models in that emissions scenario (“low” or B1, and “moderate” or A1B) for the 21st century. The colored areas indicate the range (5th to 95th percentile) for each year in 

the 21st century. All changes are relative to 1970–99 averages.
15

Adapting to Climate Change at Olympic National Forest and Olympic National Park

able to match the observed 20th-century warming (0.8 °C 

since 1920, or +0.1 °C per decade for 1920 to 2000) in the 

Northwest, and project a warming rate of roughly +0.3 °C 

per decade in the 21st century. Projected changes in annual 

precipitation (fig. 3.2) differ considerably between models, 

but averaged over all models are small (+1 to +2 percent). 

Seasonal changes in climate are arguably more important for projecting the impacts of climate change on forests. 

Warming is expected to occur during all seasons, with most 

models projecting the largest temperature increases in summer (fig. 3.3). Seasonal changes in precipitation early in the 

21st century may not be separable from historical conditions 

given the large natural variations between wetter and drier 

years. Some GCMs suggest large seasonal changes (fig. 3.4), 

but the ensemble means point toward wetter winters (+3.3 

percent in the 2040s, +7.6 percent in the 2080s, averaged 

over all A1B and B1 scenarios) and drier summers (-8.5 

percent in the 2040s, -12.8 percent in the 2080s, averaged 

over all A1B and B1 scenarios). 

Regional climate modeling (weather models forced with 

GCMs in the future, Salathé et al. 2010) points out areas and 

seasons that get drier even as the region gets wetter. The 

models with the most warming also produce the most summer drying. Regional climate models project some changes 

that are similar across global models, namely increases in 

extreme high precipitation in western Washington (including the southwestern Olympics) and reductions in Cascade 

Range snowpack. Regional climate models project a larger 

increase in extreme daily heat and precipitation events 

in some locations than the GCM ensemble suggests, the 

former being true of the southwestern Olympic Peninsula 

(Salathé et al. 2010). Regional climate models also suggest 

Figure 3.3—Range (lowest to highest) of projected changes in 

temperature for each season (DJF [December, January, and February] = winter, etc.), relative to the 1970–99 mean, for the Pacific 

Northwest region. In each pair of box-and-whiskers, the left one is 

for emission scenario B1 and the right is scenario A1B; circles are 

individual model values. Box-and-whiskers plots indicate 10th and 

90th percentiles (whiskers), 25th and 75th percentiles (box ends), 

and median (solid middle bar) for each season and scenario. Not 

all values are visible due to symbol overlap. Printed values are the 

weighted reliability ensemble average of all global climate models 

for the season and scenario. 

Figure 3.2—Simulated precipitation change for the 20th- and 

21st-century global climate model simulations for the Pacific 

Northwest region. The black curve is the weighted average of 

all models during the 20th century. The colored curves are the 

weighted average of all models in that emissions scenario (“low” 

or B1, and “moderate” or A1B) for the 21st century. The colored 

areas indicate the range (5th to 95th percentile) for each year in the 

21st century. All changes are relative to 1970–99 averages.
16

GENERAL TECHNICAL REPORT PNW-GTR-844

that some local changes in temperature and precipitation 

may be quite different than average regional changes 

projected by the global models. For example, the two global 

models examined suggest winter precipitation will increase 

in many parts of the Pacific Northwest, but potentially 

decrease in the Cascade Range. Future research is required 

to understand if this trend is consistent across many global 

models. 

These comparisons between global and regional models 

are not yet developed to the point that they are a strong basis 

for decisionmaking; additional models would be needed 

to characterize the likely seasonal trends expected in the 

future. Currently, their chief use is as a research tool to 

better understand where the inferences derived from global 

models are likely to hold up best, which process may influence rates of change differently within a region, and which 

changes might be expected to exacerbate extreme events 

(e.g., prolonged droughts or high-intensity storms). On the 

Olympic Peninsula, for example, it is possible that decreases 

in snowpack in spring will lead to higher rates of warming 

in spring than the regional average owing to the loss of the 

snow albedo feedback, an effect that the GCMs would not 

likely capture.

Climatic Downscaling: Winter Precipitation 

and Water Deficit

The GCMs produce output at relatively coarse scales (100 

km or greater) and do not yet operate at scales that provide 

future climate estimates useful for subregional planning. 

However, downscaled future climate projections at more 

local scales are based on the relationship between finer 

scale historical observations and the GCM during the same 

historical period. The best way to constrain uncertainty in 

future regional climate associated with the high number of 

potential GCM futures is to use the fidelity of each model 

to the 20th century observed record to gage its usefulness 

for regional projection (Mote and Salathé 2010). In the 

WACCIA comparison of GCMs (Mote and Salathé 2010), 

models were weighted according to their fidelity to construct an ensemble average or an average of all models that 

gives more weight to models that did well in predicting past 

climate in the region. However, another approach to this 

problem (Hamlet et al. 2010, Overland and Wang 2007) is 

to constrain the average to models that best estimate 

observed climate (i.e., models that have the smallest bias 

in temperature and precipitation and that simulate the 

Figure 3.4—Range (lowest to highest) of projected changes in 

precipitation for each season (DJF [December, January, and 

February] = winter, MAM [March, April, and May] = spring, JJA 

[June, July, and August] = summer, SON [September, October, and 

November] = fall), relative to the 1970–99 mean, for the Pacific 

Northwest region. In each pair of box-and-whiskers, the left one 

is for emission scenario B1 and the right is scenario A1B; circles 

are individual model values. Box-and-whiskers plots indicate 10th 

and 90th percentiles (whiskers), 25th and 75th percentiles (box 

ends), and median (solid middle bar) for each season and scenario. 

Not all values are visible due to symbol overlap. The height of the 

bars indicates actual water precipitation, but the percentages are 

calculated with respect to a reference value for that season, so that 

-11 percent in JJA is much less than -11 percent in DJF. The reference values for the extremes are that model’s 20th-century mean 

for that season (or annual mean), and for the Reliability Ensemble 

Average, the reference is the all-model 20th-century value. Some 

models project increases and some project decreases for a season, 

although the vast majority project decreases for summer and 

increases for winter by the 2080s. 
17

Adapting to Climate Change at Olympic National Forest and Olympic National Park

most realistic annual cycle in these parameters). Hamlet 

et al. (2010) evaluated a pool of 20 GCMs run for the A1B 

scenario in IPCC Fourth Assessment Report (Solomon et 

al. 2007) and selected 10 models, eliminating models that 

do a poor job of estimating climate change already known 

to have occurred. In this section on deficit, the average 

(ensemble) is composed of this subset of the available 

GCMs: UKMO-HadCM3, CNRM-CM3, ECHAM5/MPIOM ECHO-G, PCM, CGCM3.1(T47), CCSM3, IPSL-CM4, 

MIROC3.2(medres), and UKMO-HadGEM.

Elsner et al. (2010) described methods and results for 

future climatic downscaling and incorporation into hydrologic modeling by using the Variable Infiltration Capacity 

(VIC) hydrologic model. Littell et al. (2010) showed that 

Washington forest ecosystem processes such as tree growth 

and fire are directly associated with potential evapotranspiration, actual evapotranspiration, and their difference 

(water balance deficit [DEF]), particularly in summer. The 

DEF is effectively the difference between water demand by 

the atmosphere and water supply in the soil profile; when 

demand exceeds supply, there is deficit. These variables are 

derived from temperature, precipitation, and other physical 

variables in VIC. Future changes in June to August (JJA) 

water balance deficit on the Olympic Peninsula (2040s, scenario A1B) are greatest in the northeast, east, and southeast, 

with increases (effectively drier) of 0.4 in (10 mm) to 2.4 in 

(60 mm) depending on location, likely because of increased 

evapotranspiration associated with increased temperature 

(fig. 3.5). Some of the highest elevations suggest decreases 

in deficit of similar magnitude, likely owing to increased 

snowmelt. 

Winter (December to February [DJF]) precipitation 

on the Olympic Peninsula is likely to increase (fig. 3.6) 

by about 4.5 to 5 percent, on average and depending on 

location. Precipitation increases suggested by the GCM 

ensemble should be considered as general estimates of 

future trends, because the GCMs do not have sufficient 

topographic detail to describe fine-scale differences 

in future precipitation. However, Salathé et al. (2010) 

presented results from regional climate models (weather 

models forced with GCMs) that show significant increases 

in the intensity of winter precipitation in the western 

portion of the Olympic Peninsula. Although there is some 

uncertainty in this projection because relatively few climate 

models were used, these results suggest that portions of the 

Olympic Peninsula will receive not only more precipitation, 

but that it will come in the form of more intense storms.

Figure 3.5—Historical June to August (JJA) water balance deficit 

in the Pacific Northwest and projected changes from historical for 

the 2020s, 2040s, and 2080s (A1B and B1 emissions scenarios). 

Deficit increases in most of the drier parts of the Columbia River 

basin, but on the Olympic Peninsula, most increases are confined 

to the north, northeast, and southeast.
18

GENERAL TECHNICAL REPORT PNW-GTR-844

Summer (June to August [JJA]) potential evapotranspiration (one component of water balance and closely related 

to fuel moisture and tree stress) is expected to increase by 

5 to 18 mm by the 2040s (fig. 3.7), with most of the largest 

increases in lower elevation forests in the northeastern 

portion of the peninsula.

Literature Cited

Elsner, M.M.; Cuo, L.; Voisin, N. [et al.]. 2010. 

Implications of 21st century climate change for the 

hydrology of Washington state. Climatic Change. 

102: 225–260.

Figure 3.6—(A) Future (2040s) December to February (DJF) precipitation and (B) change from 1916 to 

2006 precipitation for the Olympic peninsula based on statistically down-scaled Global Climate Model 

(GCM) information for 10 GCM models. Olympic National Park and Olympic National Forest are 

outlined in white. The largest increases in precipitation are in the southwestern Olympic Peninsula. 
19

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Hamlet, A.F.; Salathé, E.P.; Carrasco, P. 2010. 

Statistical downscaling techniques for global climate 

model simulations of temperature and precipitation 

with application to water resources planning studies. 

Washington HB 2860 project draft report. http://www.

hydro.washington.edu/2860/products/sites/r7climate/

study_report/CBCCSP_chap4_gem_draft_20091209.pdf. 

(4 April 2010).

Littell, J.S.; Oneil, E.E.; McKenzie, D. [et al.]. 2010.

Forest ecosystems, disturbance, and climatic change in 

Washington State, USA. Climatic Change: 102: 129–158.

Figure 3.7— (A) Future (2040s) June to August (JJA) potential evapotranspiration (PET) and (B) change 

from 1916 to 2006 June to August baseline PET for the Olympic Peninsula based on downscaled climate 

projections and Variable Infiltration Capacity hydrologic modeling (Elsner et al. 2010). Olympic National 

Park and Olympic National Forest are outlined in black. Increased PET is related to decreased soil 

moisture and increased drought stress. The largest increases in PET are in the northeastern Olympic 

Peninsula.
20

GENERAL TECHNICAL REPORT PNW-GTR-844

Mote, P.W.; Salathé, E.P., Jr. 2010. Future climate in the 

Pacific Northwest. Climatic Change. 102: 29–50.

Nakićenović, N.; Swart, R., eds. 2000. Special report on 

emissions scenarios. A special report of Working Group 

III of the Intergovernmental Panel on Climate Change. 

Cambridge and New York: Cambridge University Press. 

599 p.

Overland, J.E.; Wang, M. 2007. Future regional Arctic sea 

ice declines. Geophysical Research Letters. 34: L17705. 

Raupach, M.R.; Marland, G.; Ciais, P. [et al.]. 2007. 

Global and regional drivers of accelerating CO2 

emissions. Proceedings of the National Academy of 

Sciences. 104: 10288–10293. 

Salathé, E.P., Jr.; Zhang, Y.; Leung, L.R.; Qian, Y. 2010. 

Regional climate model projections for the State of 

Washington. Climatic Change. 102: 51–75.

Schellnhuber, H.J.; Cramer, W.; Nakićenović, N. [et al.], 

eds. 2006. Avoiding dangerous climate change. New 

York: Cambridge University Press. 392 p.

Solomon, S.; Quin, D. Manning, M. [et al.]. 2007. Climate 

change 2007: the physical science basis; a contribution 

of working group I to the fourth assessment report of the 

Intergovernmental Panel on Climate Change. Cambridge 

and New York: Cambridge University Press. 996 p.
21

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Potential Effects of Climate Change on 

Hydrology on the Olympic Peninsula

Temperature, Snowpack, and Timing of 

Streamflow

Across the Western United States, increasing temperatures 

over the last 50 years have led to more precipitation falling 

as rain rather than snow, earlier snowmelt (Hamlet et al. 

2007, Stewart et al. 2005), and reduced spring snowpack 

(Barnett et al. 2008, Hamlet et al. 2005, Mote 2003, Mote 

et al. 2005). Further reductions in snowpack and shifts in 

timing of snowmelt are expected with increasing temperatures in the 21st century. April 1 snow water equivalent (a 

measure of water in snowpack) is projected to decrease by 

an average of 27 to 29 percent across Washington state by 

the 2020s, 37 to 44 percent by the 2040s, and 53 to 65 percent by the 2080s (Elsner et al. 2010) (fig. 4.1). The greatest 

reductions in snowpack are expected for lower elevations 

(<1000 m) because of warmer midwinter temperatures at 

these elevations (Elsner et al. 2010, Hamlet et al. 2005).

Changes in snowpack are particularly important for the 

mountainous regions of the Western United States, including the Pacific Northwest, because snowmelt provides about 

70 percent of annual streamflow in these regions (Mote et 

al. 2008). Warming temperatures affect the timing of snowmelt and associated seasonal streamflow. Both increased 

winter rain (as opposed to snow) and shifts to earlier spring 

snowmelt result in higher winter and spring streamflows 

and lower summer streamflows in snowmelt-dominated 

and transient (rain/snow mixed) watersheds (Elsner et al. 

2010, Stewart et al. 2005). Snowmelt-dominant watersheds 

store most winter precipitation in snowpack. This snowpack 

melts in the spring and early summer, resulting in peak 

Chapter 4: Climate Change, Hydrology, and Road Management 

at Olympic National Forest and Olympic National Park

Jessica E. Halofsky, William S. Shelmerdine, Robin Stoddard, Robert Metzger, Alan F. Hamlet, 

and Catherine Hawkins Hoffman1

1 Jessica E. Halofsky is a research ecologist, University of Washington, College of the Environment, School of Forest Resources, 

Box 352100, Seattle, WA 98195-2100; William S. Shelmerdine is a geologist/engineer, U.S. Department of Agriculture, Forest 

Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; Robin Stoddard is a forest hydrologist, 

U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; 

Robert Metzger is the aquatics program manager, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 

Black Lake Blvd. SW, Olympia, WA 98512-5623; Alan F. Hamlet is a research assistant professor, Department of Civil and Environmental Engineering, University of Washington, Box 352700, Seattle, WA 98195; Catherine Hawkins Hoffman is the Climate 

Change Adaptation Coordinator, National Park Service Natural Resource Program Center, 1201 Oakridge Dr., Fort Collins, CO 

80525 (formerly Chief, Natural Resources Division, Olympic National Park, Port Angeles, WA).

Figure 4.1—Summary of projected changes in April 1 snow water 

equivalent (SWE), an indication of snow amount, compared to 

historical for the 2020s, 2040s, and 2080s (A1B and B1 emissions 

scenarios) by the Variable Infiltration Capacity model. Percentage 

change values represent spatially averaged April 1 SWE across 

Washington state (Elsner et al. 2010). 
22

GENERAL TECHNICAL REPORT PNW-GTR-844

streamflow in the late spring or early summer and lower 

streamflow during the winter months (Elsner et al. 2010). 

Transient watersheds are primarily at mid elevations and 

receive some snow and some rain. Of the snow that these 

watersheds receive, some melts in the winter months, and 

some is stored in the winter months and melts with warming temperatures in the spring (Elsner et al. 2010). Thus, 

streams and rivers draining transient watersheds often have 

one streamflow peak in fall or early winter owing to runoff 

generated by precipitation falling as rain, and another peak 

in late spring when the snowpack accumulated in midwinter 

melts (Elsner et al. 2010). Projections for Washington state 

show that by the 2080s, there will be widespread transformation of transient watersheds to rain-dominant behavior, 

with essentially no snowmelt-dominant watersheds remaining in Washington by the end of the 21st century (Elsner et 

al. 2010). In response to these changes in natural storage 

processes, seasonal streamflow timing will shift significantly in both snowmelt-dominant and transient watersheds, 

resulting in increased winter and decreased spring and 

summer streamflows. 

Examples of projected shifts in timing of streamflow 

for river systems on the Olympic Peninsula are shown 

in figures 4.2 through 4.7. Some river systems on the 

peninsula, such as the Satsop River (not shown), are 

rain-dominant watersheds. Warming temperatures will not 

likely have a significant impact on timing of streamflow in 

rain-dominant watersheds. Several Olympic Peninsula river 

systems, such as the Queets, Skokomish, Quinault, and Hoh 

River basins (figs. 4.2 through 4.5), receive most precipitation as rain but also some as snow at higher elevations, 

and thus warming will likely have moderate impact on 

the timing of streamflow in these watersheds. Other river 

systems, such as the Elwha and Dungeness Rivers, are in 

transient watersheds. Increasing temperatures in the 21st

century will likely lead to significant increases in the winter 

and early spring peak streamflows and significant decreases 

in the summer low flows in these transient watersheds (figs. 

Figure 4.2—Simulated combined monthly 

average total runoff and baseflow over the entire 

Queets basin expressed as an average depth (millimeters). This variable is a primary component 

of the simulated water balance, and is one of the 

primary determinants of streamflow. The blue 

line shows the simulated historical values. Light 

red bands show the range of all future scenarios 

from 10 global climate models for the A1B (left 

column) and B1 (right column) emissions scenarios, and the dark red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate these 

outputs.
23

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 4.3—Simulated combined monthly 

average total runoff and baseflow over the entire 

Skokomish basin expressed as an average depth 

(millimeters). This variable is a primary component of the simulated water balance, and is one 

of the primary determinants of streamflow. The 

blue line shows the simulated historical values. 

Light red bands show the range of all future scenarios from 10 global climate models for the A1B 

(left column) and B1 (right column) emissions 

scenarios, and the red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate 

these outputs.

Figure 4.4—Simulated combined monthly 

average total runoff and baseflow over the entire 

Quinault basin expressed as an average depth 

(millimeters). This variable is a primary component of the simulated water balance, and is one of 

the primary determinants of streamflow. The blue 

line shows the simulated historical values. Light 

red bands show the range of all future scenarios 

from 10 global climate models for the A1B 

(left column) and B1 (right column) emissions 

scenarios, and the red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate 

these outputs.
24

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 4.5—Simulated combined monthly 

average total runoff and baseflow over the entire 

Hoh basin expressed as an average depth (millimeters). This variable is a primary component 

of the simulated water balance, and is one of the 

primary determinants of streamflow. The blue 

line shows the simulated historical values. Light 

red bands show the range of all future scenarios 

from 10 global climate models for the A1B 

(left column) and B1 (right column) emissions 

scenarios, and the red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate 

these outputs.

Figure 4.6—Simulated combined monthly 

average total runoff and baseflow over the entire 

Elwha basin expressed as an average depth (millimeters). This variable is a primary component 

of the simulated water balance, and is one of the 

primary determinants of streamflow. The blue 

line shows the simulated historical values. Light 

red bands show the range of all future scenarios 

from 10 global climate models for the A1B 

(left column) and B1 (right column) emissions 

scenarios, and the red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate 

these outputs.
25

Adapting to Climate Change at Olympic National Forest and Olympic National Park

4.6 and 4.7). Decreased summer flow will likely be most 

evident in the headwaters of watersheds, where flows will 

likely become increasingly ephemeral or cease altogether 

in the summer months (fig. 4.8). However, such effects are 

sometimes strongly linked to changes in groundwater in the 

basin, which are not included in the projections discussed 

above (Tague et al. 2008). Locations where deep groundwater may mediate streamflow responses on the Olympic 

Peninsula could potentially be identified through interpretation of a geological map and locating areas where intense 

fracturing has occurred. However, groundwater effects are 

unlikely to be a major influence on hydrologic changes as 

they are in regions with porous and young volcanic soils, 

such as central Oregon.

Precipitation, Storm Intensity, and Flooding

Changes in precipitation have a direct influence on streamflow and the frequency and magnitude of flooding events. 

Model projections for precipitation in the 21st century are 

much more uncertain than those for temperature. Elsner et 

al. (2010) analyzed precipitation projections of 20 global 

climate models and two future carbon dioxide scenarios for 

the Pacific Northwest, and they found that annual projected 

precipitation changes range from -9 to +12 percent for the 

2020s, -11 to +12 percent for the 2040s, and -10 to +20 

percent for the 2080s (Elsner et al. 2010, Mote and Salathé 

2010). Projections of seasonal precipitation changes, however, show increases in winter precipitation and decreases in 

summer precipitation (Elsner et al. 2010, Mote and Salathé 

2010). Projections of cool season precipitation (combining 

both A1B and B1 emission scenarios) range from +2.3 to 

+3.3 percent for the 2020s, +3.9 to +5.4 percent for the 

2040s, and +6.4 to +9.6 percent for the 2080s (Elsner et 

al. 2010). These increases in cool season precipitation are 

projected to lead to overall increases in annual runoff across 

Washington (0 to 2 percent by the 2020s, 2 to 3 percent by 

the 2040s, and 4 to 6 percent by the 2080s), although the 

effects differ for individual watersheds (Elsner et al. 2010). 

Besides potential increases in winter precipitation, 

precipitation intensity is projected to increase in some parts 

of Washington, including the west slopes of the Olympic 

Figure 4.7—Simulated combined monthly 

average total runoff and baseflow over the entire 

Dungeness basin expressed as an average depth 

(millimeters). This variable is a primary component of the simulated water balance, and is one 

of the primary determinants of streamflow. Blue 

line shows the simulated historical values. Light 

red bands show the range of all future scenarios 

from 10 global climate models for the A1B 

(left column) and B1 (right column) emissions 

scenarios, and dark red lines show the ensemble 

average for the future projections. See http://

www.hydro.washington.edu/2860 for a detailed 

description of the methods used to generate 

these outputs.
26

GENERAL TECHNICAL REPORT PNW-GTR-844

Peninsula, in the 21st century (Salathé et al. 2010). Increases 

in winter precipitation, increases in precipitation intensity, 

and changes in timing of peak streamflow in transient 

watersheds will contribute to increased flood risk in some 

of Washington’s rivers. Flooding magnitude and frequency 

are projected to increase most in December and January 

and in historically transient watersheds in Washington 

(Mantua et al. 2010). Rain-dominant watersheds will likely 

see small increases in flood frequency, whereas many 

snowmelt-dominant watersheds will likely see decreases in 

flooding owing to decreases in snowpack and corresponding decreases in snowmelt-driven peak flows in the spring 

(Mantua et al. 2010). On the Olympic Peninsula, increases 

in flood frequency are projected for many river systems (fig. 

4.8), with greater increases in flood frequency projected in 

historically transient watersheds such as the Elwha. At the 

opposite extreme, earlier snowmelt and timing of runoff 

is projected to lead to decreased low flows in the summer 

in many Olympic Peninsula watersheds (fig. 4.9). As noted 

above, effects of groundwater on summer streamflows may 

mitigate these impacts in some watersheds. 

Effects of Changing Hydrology on Physical 

Watershed Processes

Projected hydrologic effects of climate change, including more precipitation falling as rain rather than snow, 

decreased snowpack, earlier snowmelt, increased winter 

precipitation and runoff, increased storm intensity, 

increased winter and spring streamflows, reduced summer 

streamflows, increased flood frequency and magnitude, 

and elevation shifts in transition (rain on snow) zones, 

will likely affect physical watershed processes (table 

4.1). Increased precipitation and storm intensity, higher 

snowlines (increasing effective basin area), and loss of snow 

Figure 4.8—Projected increases in 20-year 

floods on the Olympic Peninsula. Numbers 

indicate the ratio of projected 20-year flood 

statistics for the 2040s to 20th-century flood 

statistics at select locations under the A1B 

carbon dioxide emission scenario. Higher 

numbers, and larger and darker red dots, 

indicate higher projected increases in 20-year 

flood frequency. Olympic National Park and 

Olympic National Forest are outlined in dark 

gray. (Adapted from Mantua et al. 2010.) 
27

Adapting to Climate Change at Olympic National Forest and Olympic National Park

cover are expected to lead to increased rate and volume of 

water delivery to channels, increased mass wasting and 

debris flows, and increased sediment and wood delivery 

to streams (Benda and Dunne 1997). Increased winter 

and spring flow volume in streams will lead to increased 

flood-plain inundation, increased channel migration, and 

increased channel erosion and scour. Other climate-related 

stressors, such as fire and tree mortality (see chapter 6), 

could also exacerbate these hydrologic effects of climate 

change on physical watershed processes. 

Road Management at Olympic National 

Forest and Olympic National Park

The following section provides information on road management at Olympic National Forest (ONF) and Olympic 

National Park (ONP) including (1) the context in which ONF

and ONP manage roads, (2) the guidance and constraints 

Figure 4.9—Projected decreases in low 

streamflows on the Olympic Peninsula. 

Numbers indicate the ratio of projected 

20-year low streamflow statistics for the 

2040s to 20th-century low flow statistics 

under the A1B carbon dioxide emission 

scenario. Lower numbers, and smaller and 

darker red dots, indicate higher projected 

decreases in low flow. Olympic National Park 

and Olympic National Forest are outlined 

in dark gray. (Adapted from Mantua 

et al. 2010.)

on road management at ONF and ONP, and (3) the primary 

issues around and activities currently conducted in road 

management at ONF and ONP. This information, coupled 

with the likely impacts of climate change on hydrology on 

the Olympic Peninsula (described above), provides a basis 

on which to develop climate change adaptation options for 

road management at ONF and ONP. 

Road Management at Olympic National Forest 

Olympic National Forest has 3500 km of roads. Most of 

these roads were built between 1950 and 1980, primarily for 

logging purposes, by using practices that are not consistent 

with today’s standards. The high number of roads, heavy 

rainfall, steep slopes, frequent storm damage, and high recreational demand for well-maintained forest roads all lead 

to high road maintenance costs at ONF. However, funding 

allocated for road maintenance, upgrading, and decommissioning at ONF is limited. 
28

GENERAL TECHNICAL REPORT PNW-GTR-844 Table 4.1—Projected climate change effects and adaptation options in the context of road management at Olympic National Forest (ONF) and Olympic National Park (ONP) Projected Adaptation climate Projected effects on Current management change physical watershed and expected options Barriers and Program Project effectsa processes sensitivities and strategies information needed Road Planning 2, 6–10 • Increased flow • Culvert capacity • Prioritize road • National Highway maintenanceb volume • Water diversion treatment by Safety Act fund • Increased mass • Fill-slope failures watershed risk and requirements (ONF) wasting and • Stream-adjacent road risk (the roads • Maintenance funding avalanches road failure with the most limitations • Increased sediment sensitivities and that • Need assessments to delivery are most connected refine links to physical • Increased flood-plain to streams) process and response

 inundation • Increased channel  migration

Implementation 1, 5–9 • Increased flow • Culvert capacity • Increased maintenance • National Highway

 volume • Culvert plugging (preparation and Safety Act fund• Increased mass • Water diversion response), including: requirements (ONF) wasting/debris flows • Fill-slope failures Culvert cleaning • Maintenance funding

• Increased sediment • Extension of channel Armoring outlets limitations

 delivery to culvert network (development and ditches • Physical barriers to inlets and ditches of first-order channels) Installing water road access in winter• Increased rate and bars and drivable

 volume of water dips delivery to channels• Increased transport  of wood in channels

Road Planning 2, 5–10 • Increased flow • Culvert capacity • Prioritize road • National Highway

 operations volume • Water diversion treatment by Safety Act fund

• Increased mass • Fill-slope failures watershed risk and requirements (ONF) wasting and • Stream-adjacent road road risk (the roads • Road funding avalanches failure with the most limitations• Increased sediment • Encroachment from sensitivities and that • Need assessments to delivery stream-adjacent are most connected refine links to physical• Increased flood-plain road segments to streams) process and response inundation • Assess possibilities • Need feasibility studies• Increased channel to design more for mass transit

 migration sustainable road types options (ONP)

 for the future 
29

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 4.1—Projected climate change effects and adaptation options in the context of road management at Olympic National Forest (ONF) and Olympic National Park (ONP) (continued)

Projected Adaptationclimate Projected effects on Current managementchange physical watershed and expected options Barriers and

Program Project effectsa processes sensitivities and strategies information needed 

Design: 2, 5–10 •Increased flow • Culvert capacity • Design more resilient • Need method to

Water volume • Foundation scour structures (design calculate Q100

crossing • Increased sediment • Lateral channel resilient bridges and (historical or recent

Fish and wood transport adjustments larger structures, and data?) or an alternativepassage • Increased channel incorporate channel

 migration geomorphic attributes

 in structure design)

Design: 7–10 • Increased flow • Stream-adjacent road • Relocate road • Revisit access and  Bank volume failure segment, travel management

 protection • Increased erosion • Cut-bank failures on decommission road plan and develop 

 and scour montane and subalpine segment, or accept better resolution in• Increased channel roads higher maintenance identifying sensitive migration costs (ONF) stream-adjacent roads• Increased mass • In a scenario-planning • Need geomorphic wasting and context, analyze analyses of other avalanches roads and road (park) rivers bordered

 segments (ONP) by roads (ONP)• Install retaining walls • No funding source or other cut-bank for proactive, sustainable stabilization (ONP) bank protection 

• Emergency Relief for  Federally Owned Roads funding policies limit or preclude sustainable  road restoration options

Design: 7–10 • Potential increase • Increased potential • Decrease reliance on • May have to adjust New in capture and for ditch or culvert drainage structures thinking regarding construction concentration of plugging and diversion • Increase frequency of design life and

 water • Increased potential for drainage discharge therefore life cycle• Potential decrease erosion and scour at points costs in alternative in slope stability pipe outlets •Increase redundancy comparisons 

 or backup features• Limit consequence  of failure• Adjust alignment, roll  with topography
30

GENERAL TECHNICAL REPORT PNW-GTR-844 Table 4.1—Projected climate change effects and adaptation options in the context of road management at Olympic National Forest (ONF) and Olympic National Park (ONP) (continued) Projected Adaptation climate Projected effects on Current management change physical watershed and expected options Barriers and Program Project effectsa processes sensitivities and strategies information needed Design 7–10 • Increased flow • Culvert capacity • Implement more • Revisit access and Reconstruction volume • Culvert plugging; water conservative design travel management Drainage • Increased rate and diversion elements (more plan and develop upgrades volume of water • Fill-slope failures intensive treatments better resolution for Stabilization delivery to channels • Extension of channel such as larger identifying road Storm-proofing • Increased sediment network (development diameter culverts, vulnerability (consider and wood transport of first-order channels) closer spacing rain-on-snow and • Increased mass between ditch relief increased storm

 wasting/debris culverts and waterbars) intensity) (ONF) flows • Increase maintenance- • Region 6 is currently• Increased sediment frequency of drainage developing a road delivery to culvert features storm-damage risk inlets and ditches reduction guide (ONF)

Design: 7–10 • Increased runoff • Increased erosion • Implement more

 Decommis- • Increased flow with sediment conservative design sioning (ONF) volume; increased delivery to channels elements (bigger

 channel migration channels, more

• Increased sediment drainage, more  transport outsloping, increased• Increased mass armoring of outlets)  wasting and debris 

 flows• Increased flood- plain inundation

Road Implementation 1, 5–9 • Increased flow • Increasing number of • Continue efforts to • National Highway operations volume projects needed to improve, stabilize, Safety Act

• Increased mass reduce resource risk and reduce existing requirements (ONF) wasting/debris flows and road failures road system • Funding limitations• Increased sediment • Limited funding • Focus road • Physical barriers to delivery to culvert • Changes in project improvements in road access owing inlets and ditches work periods priority areas to storm damage
31

Adapting to Climate Change at Olympic National Forest and Olympic National Park

To help prioritize road management activities at ONF, 

a road management strategy (RMS) was developed in 2000 

that assessed the risks that individual road segments posed 

to various resources, especially aquatic resources, against 

the need for access that the road provided. The RMS was 

developed at least partly in response to the aquatic restoration mandate of the Northwest Forest Plan (USDA and 

USDI 1994). The RMS is used for setting priorities for road 

maintenance, upgrading, and decommissioning (see box 

4.1 for specific activities in these categories) and considers 

five factors, each of which incorporates particular indicators. These five factors include aquatic risk, access needs, 

wildlife concerns, high-value watersheds, and silvicultural 

opportunities (box 4.2). In general, roads that present high 

risk to aquatic systems, are needed for access (by the public 

or for activities such as restoration thinning), impact threatened or endangered species, and are located in high-value 

watersheds are prioritized for maintenance, stabilization, 

and upgrading. Roads that meet the above criteria but are 

not necessary for access are prioritized for decommissioning (e.g., fig. 4.10). 

In addition to being guided by the RMS, road management at ONF is guided by the access and travel management (ATM) plan, which is a strategic management tool 

that describes the proposed future road system. The ATM 

was updated by forest managers in 2003. By using RMS 

information as a starting point, managers conducted a 

road-by-road evaluation on about 3300 km of road, during 

which RMS data were supplemented by the site-specific 

knowledge of interdisciplinary ONF District ATM teams 

to generate draft proposals for the long-term management 

of forest roads. Public and tribal involvement was also a 

critical component of the ATM plan update. The updated 

ATM plan proposes substantial reductions in road mileage 

throughout many watersheds at ONF owing to declining 

road maintenance funding, reduced need for access, and 

high risk to aquatic habitat. Nearly one-third of the forest’s 

roads are proposed for decommissioning.

Road Management at Olympic National Park

There are more than 225 km of paved and unpaved visitor 

use roads at Olympic National Park (ONP). There are no 

Table 4.1—Projected climate change effects and adaptation options in the context of road management at Olympic National Forest (ONF) and Olympic National Park (ONP) (continued)

Projected Adaptationclimate Projected effects on Current managementchange physical watershed and expected options Barriers and

Program Project effectsa processes sensitivities and strategies information needed 

• Increased rate and • Seek out additional volume of water funding to implement

 delivery to channels improvements

• Increased wood  transport a Projected climate change effects relevant to road management:

 (1) Increased winter air temperatures/fluctuation above and below freezing (2) More precipitation falling as rain rather than snow (3) Decreased snowpack (4) Earlier snowmelt (5) Increased winter and spring streamflows in some types of watersheds (6) Decreased summer streamflows in some types of watersheds (7) Increased winter precipitation and runoffb Road maintenance activities ensure that existing roads function correctly (defined by policy). 

(8) Increased storm intensity(9) Increased flood frequency and magnitude in some types of watersheds(10) Elevation shifts in transition (rain-on-snow) zones
32

GENERAL TECHNICAL REPORT PNW-GTR-844

cross-park roads; however, roads do penetrate the park’s 

perimeter and front-country areas, often along major river 

drainages. Roads and other infrastructure located within 

flood plains of the Olympic Peninsula have a high risk of 

being damaged during storm events. Coastal rivers located 

in the temperate rain forest exhibit a broad range of flows. 

For example, the summer low flow in the Queets River for 

the 2007 water year was about 10 m3/s, while the peak flow 

for the year was 1190 m3/s, or two orders of magnitude 

higher (USGS 2008). The record flow for the Queets River 

is 4080 m3/s, which approximates the mean annual flow of 

the Columbia River (USGS 2008). 

The ONP General Management Plan (GMP) (NPS 

2008) calls for all existing roads to be maintained in a 

sustainable manner and for improving mass-transit opportunities. Objectives and desired conditions described in the 

plan relevant to the road system include the following:

• Park managers will use the most current and feasible 

engineering methods and techniques that minimize 

adverse effects on natural river processes to protect 

park roads and facilities located in flood plains. 

• Park managers will inventory flood-prone areas near 

facilities and roads, and develop a program to proactively protect or relocate these facilities by using the 

most current techniques that minimize adverse effects 

on aquatic and riparian habitats and fluvial processes.

• Park managers will work with area partners, including 

tribes, federal, state, and county agencies, and others, 

to develop restoration plans for at-risk river systems, 

and for incorporating current technologies, over time, 

to restore or improve flood-plain and riparian functions 

altered in the past by bank-hardening techniques.

If park facilities are damaged or destroyed by a hazardous natural event, park managers will thoroughly evaluate 

options for relocation or replacement by new construction 

at a different location. If a decision is made to relocate or 

replace a severely damaged or destroyed facility, it will be 

placed, if practicable, in an area believed to be free from 

natural hazards.

The GMP specifically calls for road management 

plans to be developed in cooperation with federal, state, 

Box 4.1—Common road management activities 

at Olympic National Forest (ONF) and Olympic 

National Park (ONP). Many of these activities 

will likely be influenced, in frequency or nature, 

by climate change.

Road maintenance activities—

• Culvert cleaning, replacement, and installation 

• Grading

• Slide removal

• Erosion control 

• Brushing 

• Hazard and downed tree removal (developed areas 

 only at ONP)

• Pavement repair 

• Bridge maintenance 

• Gate installation and maintenance 

• Painting 

• Shoulder maintenance 

• Ditch cleaning and drainage maintenance

• Water bar and dip installation

Storm-proofing and road drainage upgrading 

 activities—

• Correcting stream-diversion potentials at stream 

 crossings 

• Removing unstable fill (ONF) 

• Rerouting road drainage to stable areas 

• Adding new culverts 

• Installing proper-sized culverts

• Lowering fills (ONF) 

• Hardening stream crossings (ONF)

• Lowering inlets 

• Out-sloping 

• Installing waterbars (ONF)

Road decommissioning activities (ONF)—

• Removing culverts 

• Ripping or decompacting road surfaces 

• Out-sloping 

• Removing unstable fills 

• Removing bridges or converting road bridges to trail 

 bridges 

• Constructing waterbars 

• Seeding/planting 

• Installing erosion control measures 

• Placing travel barriers
33

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Box 4.2—Critical factors and associated indicators considered in road work prioritization under 

the Olympic National Forest road management strategy.

Aquatic risk:

Geologic hazard—This factor identifies those roads located within potentially unstable terrain or within areas with 

high sensitivity to erosion. In this context, it is used as an aquatic habitat and water quality risk factor. It evaluates 

the terrain that the road is located on, not the terrain above the road. It is intended to be a reflection of the potential to 

initiate erosion or mass wasting from roads themselves rather than the potential for impacts to roads from processes 

initiated upslope.

Proximity (delivery) to fish habitat—This factor uses a combination of sediment delivery efficiency and physical 

distance from the fish-bearing portions of the stream network. It provides an estimate of how direct any road effects 

would be on fish and fish habitat.

Stream crossing density—The stream crossing density factor determines the relative hazard associated with stream 

crossing(s) within the road segment, defined as the frequency. 

Riparian zone/stream proximity—The riparian zone factor determines the relative degree of connectivity between 

the road system and the stream system. This factor considers the portion of the road segment within the riparian 

zone or near a stream. Riparian zones are defined as a 100-m buffer width, which spans both sides of the channel, as 

measured from the center of the channel.

Upslope hazard—The upslope hazard factor identifies those roads located downslope of steep converging topography or terrain designated to have a high potential for landslides. These hazard elements may initiate new hill slope 

failures or increase the magnitude of initial mass wasting events. This factor differs from the geologic hazard factor 

in that the road itself may not be on the terrain that is considered hazardous, and the problems or disturbances affecting the road or the aquatic system may not be initiated from the road itself.

Access:

Private access—This factor identifies roads that provide access to non-National Forest System lands or special use 

permit sites.

Public access—This factor identifies roads that provide access to national forest-developed recreation sites.

Administrative access—This factor identifies roads that provide access to administrative sites (facilities, rock 

sources, and communication sites).

Wildlife:

Threatened and endangered species—The wildlife factor identifies roads that lie within or intersect a 0.40-km 

radius of a known northern spotted owl activity center, a marbled murrelet occupied site, or a bald eagle activity 

center.

High-value watersheds:

These factors are used to determine whether the road segment lies within or is within areas contributing to:

 Northwest Forest Plan key watersheds 

 Municipal watersheds

 Clean Water Act 303(d) listed water bodies

 Habitat for listed fish stocks

Silvicultural:

Terrestrial habitat development (commercial thinning)—This factor considers whether the road provides access 

to stands with potential for terrestrial habitat development through commercial thinning.

Terrestrial habitat development (precommercial thinning)—This factor considers whether the road provides 

access to stands with potential for terrestrial habitat development through precommercial thinning.
34

GENERAL TECHNICAL REPORT PNW-GTR-844

and tribal partners for at-risk roads near rivers and within 

the flood plains of the Hoh, Queets, and Quinault Rivers. 

These plans may include geomorphic investigations (such 

as that prepared for a section of the Quinault River) (see 

Bountry et al. 2005), restoration, feasibility studies, and 

as appropriate, recommendations for road relocations and 

potential wilderness boundary changes that may be needed 

as rivers respond to changing hydrology associated with 

climate change. The plan includes development of a North 

Shore Road/Finley Creek management plan (Quinault) to 

address the hydrologic and geomorphic issues associated 

with maintaining year-round vehicle access in this unstable 

environment, and to return Finley Creek to a more naturally 

functioning and stable condition. Finally, related to rising 

sea levels associated with climate change, the GMP calls for 

a risk-assessment study for Highway 101 along the coastal 

portion of the park to be conducted in cooperation with the 

Washington State Department of Transportation. This study 

will identify at-risk portions of the highway and determine 

suitable areas for reroutes or road relocations.

Specific road management goals for ONP, including 

considerations for potential effects of climate change, 

include: 

• Hurricane Ridge—Road access to Hurricane Ridge 

will continue to be provided year round, and alternative 

methods of transportation (transit) will be provided 

if studies indicate it is feasible. The unpaved road to 

Obstruction Point will be maintained seasonally.

• Staircase—The Staircase road will be maintained by 

using methods that minimize adverse effects on river 

processes and aquatic and riparian habitats to the extent 

possible (NPS 2008).

• Elwha—Road access will be retained to the Boulder 

Creek and Whiskey Bend trailheads; methods will 

minimize adverse effects on river processes and aquatic 

and riparian habitats to the extent possible (NPS 2008).

• Sol Duc—Seasonal road access will be provided by 

using methods that minimize adverse effects on river 

processes and aquatic and riparian habitats to the extent 

possible (NPS 2008).

• Mora—The last 0.8 km of road will be retained unless 

lost to a catastrophic event and reconstruction is 

infeasible because of topography. This section of the 

road lies within a tsunami zone in an area of very high 

sensitivity to future sea level rise. Access to the Rialto 

Beach area will be by trail should this section of road 

be lost (Pendleton et al. 2004). 

• Hoh—Year-round road access will be provided by 

using methods that minimize adverse effects on river 

processes and aquatic and riparian habitats to the 

extent possible (NPS 2008). In the event of a flood with 

associated road loss or damage, if road relocation away 

from river meander areas is feasible, wilderness boundary changes that result in no net loss of ONP wilderness acreage will be sought as necessary (NPS 2008). 

Alternative methods of transportation (transit) would be 

provided if studies indicate it is feasible. 

• Kalaloch—The ONP will work with the Washington 

Department of Transportation to determine options 

to relocate all or portions of Highway 101 outside 

the active coastal erosion zone as needed to maintain 

access, and for the protection of the coastal portion of 

the park. Kalaloch is also in an area of very high sensitivity to future sea level rise (Pendleton et al. 2004).

• Queets—Vehicular access will be retained, but the 

road or portions of the road may be moved or closed as 

needed in response to river meandering and changing 

Figure 4.10—A decommissioned road at Olympic National Forest.

(Photo courtesy of USDA Forest Service, Olympic National 

Forest.) 
35

Adapting to Climate Change at Olympic National Forest and Olympic National Park

conditions, by using methods that minimize adverse 

effects on river processes and aquatic and riparian 

habitats to the extent possible (NPS 2008). The ONP 

will develop a plan to address long-term access options, 

and existing facilities may be removed or relocated in 

response to changing river and road conditions. 

• Quinault—The loop drive will be retained and will 

provide access to the North Fork and Graves Creek 

areas. ONP will seek options to redesign or relocate the 

Finley Creek bridge, including moving and possibly 

redesigning the North Shore Road. The North Fork and 

Graves Creek roads will be retained; relocations may be 

necessary because of river movement and river restoration goals. Year-round road access would be retained by 

using methods that minimize adverse effects on river 

processes and aquatic and riparian habitats to the extent 

possible (NPS 2008). If road relocation away from river 

meander areas is feasible, wilderness boundary changes 

that result in no net loss of ONP wilderness acreage 

would be sought as necessary.

• Dosewallips—Road access will be provided by 

using methods that minimize adverse effects on river 

processes, aquatic and riparian habitats, and old-growth 

forests, to the extent possible.

• Deer Park—No change is expected for Deer Park Road; 

the road will remain unpaved and opened seasonally as 

weather conditions permit.

Climate Change Adaptation Strategies 

and Action Items for Road Management 

at Olympic National Forest and Olympic 

National Park 

Process Used to Develop Adaptation Strategies 

for Road Management

In January 2009, ONF and ONP natural resources and 

engineering staff, and scientists from the Forest Service 

Pacific Northwest Research Station (PNW) and University 

of Washington Climate Impacts Group (CIG) convened to 

discuss adapting road management activities to climate 

change and related hydrologic changes on the Olympic Peninsula. Objectives of the workshop were to (1) learn about 

the latest climate and hydrology model projections, and (2) 

use an interactive dialogue between scientists and managers 

to explore options to incorporate climate change information into road management at ONF and ONP. The workshop 

began with a presentation from Alan Hamlet on climate and 

hydrologic model projections, and a presentation from ONF 

engineer William Shelmerdine on current road management 

at ONF. A facilitated discussion on potential adaptation 

strategies for road management at ONF and ONP followed. 

Table 4.2 and the “General Adaptation Strategies for Road 

Management” section below describe key points from the 

discussion. 

Building on the January workshop, ONF natural 

resources and engineering staff and PNW scientists further 

examined the ideas brought forth in the workshop and 

developed a strategy to use climate change information 

in road management at ONF, in particular, and to further 

inform road management activities at ONP. Participants 

concluded that climate change predictions could affect all 

aspects of road management, including (1) planning and 

prioritization, (2) operations and maintenance, and (3) 

design. A discussion of adaptation strategies developed for 

each of these areas is below, after a description of more 

general adaptation strategies for road management in the 

forest and park. See box 4.3 for a summary of projected 

climate change effects on hydrology on the peninsula and 

related adaptation strategies for road management at ONF 

and ONP. 

General Adaptation Strategies for Road 

Management

The goal of road management at ONF and ONP is to 

provide a safe and economical transportation system to 

meet the access needs of various users while minimizing 

potential adverse impacts to other resources. Recent road 

management actions at ONF have focused on reducing 

potential risk to aquatic resources by removing unstable 

roads, relocating roads and infrastructure out of valley 

bottom areas, and at both ONF and ONP, correcting culvert 

fish passage barriers (fig. 4.11), and increasing the size and 

number of drainage structures, or replacing culverts with 

bridges where appropriate. Anticipated climate change 

effects tend to validate the current road management 
36

GENERAL TECHNICAL REPORT PNW-GTR-844

efforts. In many ways, climate change will not necessitate 

large modifications of road management at ONF and ONP 

because the majority of current practices are focused on 

increasing the resilience of infrastructure and ecosystems. 

However, potential climate change effects underscore the 

need to increase activity and be proactive in priority areas 

to avoid impacts associated with infrastructure failure. 

To deal with the uncertainty associated with climate 

change, strategic planning and efforts to increase flexibility 

in road management policies will be critical. Strategic 

approaches to resource allocation and utilizing no-regrets 

strategies will likely reduce vulnerability to future climate 

change and also help to better meet current objectives. 

Increasing flexibility in forest road management policies 

will allow management actions to shift more rapidly in 

response to new information on climatic changes and 

ecosystem response.

Managers will likely need to evaluate the density, 

location, design, and maintenance intensity of roads and 

related structures in the context of climate change to avoid 

escalating road maintenance costs associated with impacts 

discussed above. For example, roads in valley bottoms are 

particularly susceptible to flood damage, and moving these 

roads to other locations, when possible, may be desirable. 

Roads within or downslope of transient snow zones or 

snow-dominated areas will likely be subjected to increased 

flood damage because of more precipitation in the form of 

rain and increased storm intensity. These roads may require 

more intense treatments or more frequent maintenance. 

Also, current methods to size culverts and guidelines to 

determine design life may no longer be appropriate under 

changing climate. 

The concept of Q100 (the peak flow anticipated in a 

100-year flood event) is a key factor currently used for road 

Box 4.3—Summary of projected climate change effects on hydrology on the Olympic Peninsula 

and related adaptation strategies for road management at Olympic National Forest and Olympic 

National Park. 

• Reductions in snowpack and shifts in timing of snowmelt and streamflow are expected across the Western United 

States with increasing temperatures in the 21st century.

• Shifts in timing of streamflow, mainly increased winter and early spring peak flows and lower summer low flows, 

are expected for many Olympic Peninsula rivers, particularly for those in transient (mixed rain and snow) basins, 

such as the Elwha and Dungeness Rivers.

• Increases in cool season precipitation are projected to lead to overall increases in annual runoff across Washington 

state.

• Increases in precipitation intensity are also expected for the west slope of the Olympic Peninsula.

• Increases in winter precipitation, increases in precipitation intensity, and changes in timing of peak streamflow will 

contribute to increased flood risk in some of the Olympic Peninsula’s rivers, particularly in December and January 

and in historically transient watersheds.

• Potential climate change effects underscore the need to increase activity and be proactive in priority areas to avoid 

impacts associated with increased infrastructure failure.

• Managers will likely need to evaluate the density, location, design, and maintenance intensity of roads and related 

structures in the context of climate change to avoid escalating road maintenance costs associated with impacts 

discussed above. For example, roads in valley bottoms are particularly susceptible to flood damage, and moving 

these roads to other locations, when possible, may be desirable to reduce maintenance costs and impacts on aquatic 

systems. 

• Roads within, or downslope of, transition or snow-dominated areas will likely be subjected to increased flood damage because of more precipitation in the form of rain and increased storm intensity. Identifying these roads may be 

useful as they will likely require more intense treatments or more frequent maintenance. 

• Also, current methods to size culverts and guidelines to determine design life may no longer be appropriate under 

changing climate. There are several alternatives, including using only the last 30 years of record (as opposed to the 

entire period of record), or using physically based model simulations to determine design discharge.
37

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 4.2—Methods to incorporate climate change into road management at Olympic National Forest 

and Olympic National Park

Adaptation 

principle Example adaptation strategies and actions

Be strategic

 and flexible • Use selectivity in allocating resources. 

• Identify no-regrets strategies that do not require an accurate design standard but meet multiple 

criteria (e.g., for fish and streamflow). For example, with culvert design, bigger culverts could be put 

in every location to accommodate higher flows and fish passage, thus avoiding the development of 

new engineering design standards every decade. A standard design that works most of the time does 

not require constant updating and the large cost associated with the updating process. 

• Work under a new climate change paradigm in road management that is less prescriptive and more 

flexible.

• Develop strategies and actions that are adaptable over time. 

• Focus on management actions that are robust to multiple future scenarios.

• Broaden options and consider which option is more prudent for time and cost: new design, relocation, 

or increased maintenance. 

• Conduct management experiments on national forests to learn valuable lessons and contribute to the 

broader interest of all land and resource managing agencies.

• Consider potential alterations to desired future conditions and alternative management pathways to 

achieve those conditions.

Reexamine road • Rethink the design-life guidelines (usually <50 years) for roads and other structures.

 locations and • Redo culvert size analysis based on peak flow data from only the last 30 years (as opposed to the 

 entire design period of record) or by using a physically based hydrology model (such as Variable Infiltration 

Capacity). 

• Consider whether existing roads are in the right locations (e.g., valley bottom roads).

• Consider sediment problems in glacier-fed rivers that can make some valley bottom roads at risk or 

unsafe (such as in Mount Rainier National Park, or potentially the Hoh and Quinault valleys).

• Consider future repair and maintenance needs in evaluating relocation options.

Use information • Use empirical data first and models second in analysis and planning. Assess sensitivities and 

 selectively trends in failures over the last 30 years and determine whether the sensitivities/failures were due to 

increased precipitation intensity or snowpack. Use the causes and consequences of past failures 

to determine where future failures will be and where actions should be focused. Consider new 

information and model predictions for the future only after that analysis. 

• Use expert knowledge when reliable quantitative data are not available. For example, instead of 

quantitative calculations of expected peak flow based on historical data, look at actual channel size 

on the ground and base culvert size on expert judgment.

Manage risk • Expect that there will be some road failures. For example, failure can be expected in debris-prone 

areas. Without proactive action to manage risk, the anticipated failure rate will increase in response 

to climate change.

• Conduct more up-front analysis and have plans in place to protect the most at-risk resources.

• Use "What if it fails?" scenarios to address risk and uncertainty in evaluating road management 

alternatives. Failures that will result in the most severe impacts are the ones to be avoided

Increase • Foster science-management partnerships. 

 communication • Engage scientists in communicating new science for management.

 and foster • Communicate with the Federal Highway Administration about projected climate change effects 

 partnerships and associated needs to widen programmatic capability and resources to respond.
38

GENERAL TECHNICAL REPORT PNW-GTR-844

management and stream crossing design. Calculation of 

this metric may need to shift under a changing climate. For 

example, instead of quantitative calculations of expected 

peak flow based on historical data, culvert size could be 

based on a qualitative ground-based assessment within an 

expert systems framework. Alternatively, physically based 

hydrologic models that incorporate changes in climate could 

provide quantitative estimates of changes in Q100 or other 

factors affecting design decisions. Assessing changing sensitivities and trends over the last 30 years (and their relationship to projected 21st century impacts) may also give a more 

accurate picture of future sensitivities and trends than the 

entire period of record. Looking for evidence of precession 

of peak flows or of the temporal centroid of the hydrograph, 

and determining the rate at which any change is occurring, 

may be useful to managers in determining how rapidly 

hydrologic effects of climate change are being realized. 

Observed trends may also provide important information 

needed to augment and validate model predictions (further 

discussion below). 

Regardless of forward-thinking design or restoration 

methods used for roads, uncertainties associated with rainfall, steep slopes, and the transport of water, sediment, and 

wood in stream channels make some level of road failure 

inevitable. Climate change will exacerbate these uncertainties and associated risks. However, several strategies can 

minimize risk and failure. For example, inventorying and 

analyzing high-risk areas, such as debris-prone sites, can 

support development of plans to prevent or manage issues in 

these areas. In addition, “what if it fails?” scenario analyses 

can identify likely failures that will result in the most 

adverse consequences. This information can help to target 

sensitive areas in strategic planning to emphasize specific 

actions to avoid these impacts (e.g., specifying more robust 

design criteria for these areas).

Communication and partnerships are needed for adapting road management to climate change on the peninsula. 

Topography constrains potential road-access options; roads 

can affect important resource values such as fish and riparian resources; and forest management, recreation, tourism, 

and residential access are essential. The present case study 

serves as an example of the utility of science-management 

partnerships that facilitate communication and help to 

address challenges and barriers to climate change adaptation.

Adaptation Strategies for Road Management 

Planning and Prioritization at Olympic National 

Forest

The RMS at ONF is a tool to evaluate the use or need for 

all of the roads in the transportation system against the 

potential risks the roads pose to other resources. Identified through analysis with RMS criteria, priority roads for 

decommissioning are those determined to be of low use 

volume or need, and high environmental impact. A major 

category in evaluating road risk is risk to aquatic resources. 

The RMS applies five rating factors to assess aquatic risk: 

(1) geologic hazard, (2) proximity (delivery) to fish habitat, 

(3) stream crossing density, (4) riparian zone proximity, and 

(5) upslope hazard. Climate change will likely influence 

all of these aquatic risk factors. The ONF engineering and 

natural resources staff identified three of the aquatic risk 

factors to focus discussion of adaptive strategies for road 

management planning and prioritization: proximity (delivery) to fish habitat, riparian zone proximity, and upslope 

hazard. 

Figure 4.11—Fish passage culvert at Olympic National Forest. 

(Photo courtesy of USDA Forest Service, Olympic National 

Forest.)
39

Adapting to Climate Change at Olympic National Forest and Olympic National Park

The upslope hazard factor developed in the RMS incorporates geologic hazard and delivery conditions within the 

hill slope immediately upslope of the road segment being 

evaluated. It identifies roads located downslope of either 

steep converging topography or terrain designated as having 

a high potential for landslides. These hazard elements may 

initiate new hill slope failures or increase the magnitude of 

initial mass wasting events. To incorporate climate change 

predictions, ONF proposes to modify the upslope hazard 

factor to consider the amount of area upslope that is in the 

transient snow zone or rain-on-snow (ROS) zone. With 

increasing temperatures, there will be shifts in the location 

and extent of ROS zones. High rates of water delivery to 

soils in ROS zones can be associated with mass wasting of 

hill slopes, and thus hill slopes with increasing area of ROS 

are potentially more susceptible to slope failure (Swanson 

and Dyrness 1975, Swanson et al. 1998, Wemple et al. 

2001), which will affect use and maintenance of the adjacent 

road. 

Scientists and engineers can predict future locations of 

ROS zones by using a model that accounts for factors such 

as climate, snow cover, and elevation. The ONF proposes 

to model the area within the ROS zone in hill slope areas 

above and connected to road segments, and evaluate road 

segments for ROS under current conditions and future 

projected conditions (e.g., 2040). Assessment of current 

and future hazard evaluations will flag areas with a higher 

hazard rating under projected future conditions as priorities 

for maintenance, upgrading, or decommissioning. This 

comparative evaluation will support recommendations for 

increased frequency and intensity of road treatments for 

some roads, as well as recommendations to decommission 

other road segments rather than continue efforts to maintain 

them.

Riparian area and stream proximity are also used to 

evaluate the risks that roads present to aquatic systems 

under the 2000 RMS. Managers consider stream-adjacent 

or riparian area roads to be risky owing to their often direct 

and deleterious effects on aquatic habitats. Stream-adjacent 

roads also have high potential for frequent damage from 

floods and stream channel changes, resulting in higher 

maintenance costs. To incorporate climate change predictions, ONF proposes to modify the riparian area/stream 

proximity factor in the RMS by manually validating the 

locations of stream-adjacent roads and degree of connectivity of these roads to streams. Olympic National Forest engineers will assess roads under current and future projected 

conditions, and assign a higher (riparian zone proximity) 

hazard rating to those that are determined to be within 

a projected flood hazard corridor (in a potential area of 

inundation or channel migration zone, or in a geotechnical 

setback buffer). Highest priorities for maintenance, upgrading, or decommissioning will focus on roads with higher 

hazard ratings under future projected conditions (e.g., roads 

at higher risk owing to increased flood risk).

Adaptation Strategies for Road Operations and 

Maintenance at Olympic National Forest and 

Olympic National Park

Assessing current road maintenance and operations tasks 

conducted at ONF and ONP in the context of climate 

change can inform managers of necessary changes. For 

example, climate change will likely influence watershed 

processes, resulting in increased flow volume, increased 

mass wasting and debris flows, increased sediment delivery 

to culvert inlets and ditches, increased rate and volume of 

water delivery to stream channels, and increased transport 

of wood. These changes will likely increase the incidences 

of culvert capacity being exceeded, fill slope failures, and 

development of first-order channels that can affect roads 

and related structures (e.g., fig. 4.12). A response to these 

potential changes could involve prioritizing maintenance 

preparation and response, including increased frequency of 

culvert cleaning, installing more and larger culverts where 

appropriate, and installing water bars and drivable dips. 

Table 4.1 lists potential climate change effects and affected 

watershed processes and sensitivities associated with major 

road maintenance and operations tasks, along with potential 

strategies to address climate change issues. 

Adaptation Strategies for Road Design

Anticipating the effects from changes in watershed processes also informs the design of roads and related structures. Design of water crossing structures in the context 
40

GENERAL TECHNICAL REPORT PNW-GTR-844

of climate change, specifically culvert design, is an area of 

particular interest to both the forest and the park because 

of the increased potential for higher fall and winter flow 

volumes to exceed culvert capacity. Stream simulation is a 

method used to design culverts on fish-bearing streams that 

applies attributes of streams (geometry and geomorphology) 

to size and select water crossing structures. This method 

leads to designs that are relatively resilient to a range of 

conditions. Consequently, no changes to this method are 

proposed at this time. 

Culverts on non-fish-bearing streams are designed 

principally by analyzing predicted runoff and flow capacity. 

Standard methods applied at ONF and elsewhere include 

sizing culverts for the predicted 100-year flood and associated debris (Q100 + debris). The Northwest Forest Plan 

aquatic conservation strategy (ACS) established this standard in 1994. The standard requires that an understanding 

of watershed process and channel functions be incorporated 

in culvert design, and thus, culverts designed by using this 

standard are considerably more resilient than those designed 

under pre-ACS standards. However, there is a question as to 

whether the methods used to predict Q100 should be altered 

according to expected hydrologic effects of climate change. 

Engineers currently use the period of record to predict 

the Q100. However, flood magnitude will likely increase 

in the transient snow zone with warming temperatures. 

Predictions based on the period of record may be even less 

accurate for predicting large flows if future precipitation 

or runoff patterns change. In many Olympic Peninsula 

streams, the largest flows on record at gauged sites are 

clustered in the later part of the record (i.e., the last 20 

years). For example, at the Duckabush River gauge, the five 

largest flows in the 70-year record occurred in the past 12 

years. Deriving the same predictive equations based on the 

late, early, or entire record gives entirely different predictions of Q100. 

There are several possible ways to modify the current 

method used for prediction of design discharge (Q100 flow). 

Suggested alternatives include calculations based on the 

later part of the record, such as the past 30 years. Alternatively, the Variable Infiltration Capacity (VIC) hydrologic 

model can provide future runoff estimates under different 

scenarios of climate change, which could be used to supplement information from the period of record. The VIC model 

uses a physically based simulation of runoff processes 

combined with a unit hydrograph approach that would 

provide a more physically based analysis than the current 

Q100 calculation method. The VIC model has predictive 

capabilities related to temperature and snowpack changes, 

which the current method does not. In considering climate 

change, ONF proposes to conduct an analysis of both the 

current method and the proposed VIC-based method and 

compare results, selecting the most appropriate option based 

on hazard and consequence for a particular site. 

These analyses would not address several potential 

issues with culvert design based on predictions of Q100. 

Predictions of Q100 have been and likely will continue to 

be associated with much uncertainty, regardless of the 

method used for prediction. Predictions of Q100 also do not 

address sediment and wood, which are most frequently the 

cause of culvert failures (not excessive water) (Furniss et 

al. 1998). Thus, continued and potentially increased focus 

on geomorphic culvert design on non-fish-bearing streams 

will be important with climate change. Besides an increase 

in magnitude, the frequency of moderate floods will likely 

increase with climate change; five 20-year flood events may 

in fact cause more damage to road infrastructure than one 

100-year flood event. As noted above, increased focus on 

design of resilient structures will help avoid adverse effects 

of climate change on road systems. 

Challenges and Opportunities in Climate Change 

Adaptation in Road Management

There are many potential challenges in the implementation 

of adaptation strategies and actions in road management on 

the Olympic Peninsula (table 4.2). For example, the National 

Highway Safety Act sets specific requirements for heavily 

used roads, arterials and collectors (maintenance level 3 and 

above), and most appropriated road operations and maintenance funds focus on these higher standard roads. Valley 

bottom and stream-adjacent roads are well represented, but 

other roads are not. In general, lower standard roads at the 

head of the transportation and drainage network have higher 

hazards when it comes to slope and runoff processes, but 
41

Adapting to Climate Change at Olympic National Forest and Olympic National Park

funding generally does not target operations and maintenance on these lower standard and higher hazard roads.

Another potential policy challenge is the Federal Highway Administration Emergency Relief for Federally Owned 

Roads (ERFO) Program. This program is the principal 

source for storm damage repair funds. However, at present, 

use of these funds is generally limited to in-kind replacement (although there have been some recent exceptions). For 

example, if storm damage occurs owing to culvert failure, 

ERFO funds will cover replacement of the same size culvert 

but not a larger one that could accommodate higher flows 

and be more resilient to future floods. Such policies limit 

the ability to design replacement structures that accommodate changing conditions with climate change or other 

factors. Further collaboration with the Federal Highway 

Administration may help to alleviate these limitations.

Budgets and the need for economic efficiency present 

further challenges in climate change adaptation in road 

management. Competing with the need to implement resilient designs is the objective to be economically efficient. 

Although long-term costs may be reduced by implementing 

more resilient designs for a changing climate, costs at the 

time of construction will likely be higher than current 

designs (especially in the case of in-kind replacement 

guidelines discussed above). Thus, strategic planning and 

prioritization efforts to identify areas where more robust 

designs would be most advantageous will make the best use 

of limited financial resources for climate change adaptation.

Acknowledgments

We thank the individuals from ONF and ONP who participated in the workshop on climate change and road management in January 2009; their thoughts and ideas guided the 

development of this chapter. This chapter was improved 

with helpful reviews by Michael Furniss and Gordon Grant. 

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Barnett, T.P.; Pierce, D.W.; Hidalgo, H.G. [et al.]. 2008.

Human-induced changes in the hydrology of the Western 

United States. Science. 19: 1080–1083.

Benda, L.; Dunne, T. 1997. Stochastic forcing of sediment 

supply to channel networks from landsliding and debris 

flow. Water Resources Research. 33: 2849–2863.

Bountry, J.A.; Randle, T.J.; Piety, L.A. [et al.]. 

2005. Geomorphic investigation of Quinault River, 

Washington; 18 km reach upstream from Lake Quinault. 

Denver, CO: U.S. Department of the Interior, Bureau of 

Reclamation, Technical Service Center. 175 p.

Elsner, M.M.; Cuo, L.; Voisin, N. [et al.]. 2010. 

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hydrology of Washington state. Climatic Change. 

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Furniss, M.J.; Ledwith, T.S.; Love, M.S. [et al.]. 1998. 

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1806. San Dimas, CA: U.S. Department of Agriculture, 

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Hamlet, A.F.; Mote, P.W.; Clark, M.P.; Lettenmaier, D.P. 

2005. Effects of temperature and precipitation variability 

on snowpack trends in the Western U.S. Journal of 

Climate. 18: 4545–4561.

Figure 4.12—Ditch scour along an Olympic National Forest road. 

Changes in hydrology and physical watershed processes with climate change will likely increase the incidences of culvert capacity 

being exceeded, fill slope failures, and development of first-order 

channels that can affect roads and related structures. (Photo 

courtesy of USDA Forest Service, Olympic National Forest.)
42

GENERAL TECHNICAL REPORT PNW-GTR-844

Hamlet, A.F.; Mote, P.W.; Clark, M.P.; Lettenmaier, D.P. 

2007. 20th century trends in runoff, evapotranspiration, 

and soil moisture in the Western U.S. Journal of Climate. 

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change impacts on streamflow extremes and summertime stream temperature and their possible consequences 

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Mote, P.W. 2003. Trends in snow water equivalent in the 

Pacific Northwest and their climatic causes. Geophysical 

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2005. Declining mountain snowpack in western North 

America. Bulletin of the American Meteorological 

Society. 86: 39–49.

Mote, P.W.; Hamlet, A.F.; Salathé, E.P. 2008. Has 

spring snowpack declined in the Washington Cascades? 

Hydrology and Earth System Sciences. 12: 193–206.

Mote, P.W.; Salathé, E.P., Jr. 2010. Future climate in the 

Pacific Northwest. Climatic Change. 102(1-2): 29–50.

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Park general management plan. Port Angeles, WA: 

Olympic National Park. http://parkplanning.nps.gov/

document.cfm?parkID=329&projectId=10233&document

ID=22448. (9 February 2010).

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Williams, S.J. 2004. Coastal vulnerability assessment 

of Olympic National Park (OLYM) to sea-level rise. 

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Geological Survey. 22 p. http://woodshole.er.usgs.gov/

project-pages/nps-cvi/parks/OLYM.htm. (9 February 

2010). 

Salathé, E.P., Jr.; Zhang, Y.; Leung, L.R.; Qian, Y. 

2010. Regional climate model projections for the state of 

Washington. Climatic Change. 102(1-2): 51–75.

Stewart, I.T.; Cayan, D.R.; Dettinger, M.D. 2005.

Changes toward earlier streamflow timing across western North America. Journal of Climatology. 

18: 1136–1155.

Swanson, F.J.; Dyrness, C.T. 1975. Impact of clear-cutting 

and road construction on soil erosion and landslides in 

the western Cascade Range, Oregon. Geology. 

3: 393–396.

Swanson, F.J.; Johnson, S.L.; Gregory, S.V.; Acker, 

S.A. 1998. Flood disturbance in a forested mountain 

landscape. Bioscience. 48: 681–689. 

Tague, C.; Grant, G.; Farrell, M. [et al.]. 2008. Deep 

groundwater mediates streamflow response to climate 

warming in the Oregon Cascades. Climatic Change. 

86(1-2): 189–210.

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U.S. Department of the Interior, Bureau of Land 

Management [USDA and USDI]. 1994. Record of 

decision for amendments to Forest Service and Bureau 

of Land Management planning documents within the 

range of the northern spotted owl [Place of publication 

unknown]. 74 p. [plus attachment A: standards and 

guidelines].

U.S. Geological Survey [USGS]. 2008. USGS real-time 

water data for the Nation. http://waterdata.usgs.

gov/nwis/rt. (29 March 2010).

Wemple, B.C.; Swanson, F.J.; Jones, J.A. 2001. Forest 

roads and geomorphic process interactions, Cascade 

Range, Oregon. Earth Surface Processes and Landforms. 

26: 191–204. 
43

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Chapter 5: Climate Change, Fish, and Fish Habitat 

Management at Olympic National Forest and Olympic 

National Park

Nathan J. Mantua, Robert Metzger, Patrick Crain, Samuel Brenkman, and Jessica E. Halofsky1

1 Nathan J. Mantua is a co-director, JISAO/CSES Climate Impacts Group and research associate professor of aquatic and fishery 

sciences, University of Washington, Box 354235, Seattle, WA 98195-4235; Robert Metzger is the aquatics program manager, 

U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623;

Patrick Crain is a fisheries biologist, Olympic National Park, 600 E. Park Ave., Port Angeles, WA 98362; Samuel Brenkman is a 

fisheries biologist, Olympic National Park, 600 E. Park Ave., Port Angeles, WA 98362; Jessica E. Halofsky is a research ecologist, 

University of Washington, College of the Environment, School of Forest Resources, Box 352100, Seattle, WA 98195-2100.

Potential Climate Change Effects on 

Hydrology, Summer Stream Temperatures, 

and Fish on the Olympic Peninsula

Climate plays a crucial role in aquatic ecology, but the 

relative importance of climatic factors is quite different for 

different species, and even different populations of the same 

species. For example, key limiting factors for freshwater 

salmon productivity include thermal and hydrologic regimes 

that depend on species, their life history, watershed characteristics, and to a great extent, stock-specific adaptations 

to local environmental factors (e.g., Beechie et al. 2008, 

Crozier and Zabel 2006, Farrell et al. 2008, Richter and 

Kolmes 2005). Those stocks that typically spend extended 

rearing periods in freshwater (steelhead, stream-type chinook salmon, sockeye salmon, and coho salmon) are likely 

to have a greater sensitivity to freshwater habitat changes 

than those that migrate to sea at an earlier age (ocean-type 

chinook salmon, pink salmon, and chum salmon). Because 

they spend almost all of their life cycle in freshwater, resident rainbow trout, cutthroat trout, and bull trout are also 

likely to be sensitive to freshwater habitat changes. Effects 

of changes in marine conditions with climate change could 

interact with effects of changes in freshwater conditions to 

further affect fish populations that spend part of their life 

cycle in the marine environment. 

Mantua et al. (2010) reported on a few direct, wellunderstood mechanisms whereby more easily predicted 

physical properties of the freshwater habitat for salmon 

directly influence salmon reproductive success (or overall 

fitness) at certain stages of their life cycle. Those physical 

properties are warm season stream temperature and the 

volume and time distribution of streamflow. They did not, 

however, assess the impacts of climate change on cold 

season water temperatures and related impacts on salmon, 

and this choice directed their focus on negative, rather 

than positive, impacts of climate change on the freshwater 

habitat for Washington’s salmon. 

We describe in a report by Mantua et al. (2010) qualitatively assessed the potential effects of climate change on the 

reproductive success for salmon in Washington’s watersheds by combining salmon sensitivities described in the 

scientific literature with future scenarios for changes in the 

statistics of stream temperature and streamflows. Climate 

also influences estuarine and marine habitat for salmon. 

See reviews of climate effects on marine habitat for Pacific 

Northwest salmon in ISAB (2007), Loggerwell et al. (2003), 

and Pearcy (1992).

Summertime Stream Temperature Projections

Maximum weekly water temperatures in Washington are 

typically observed from late July through late August, 

similar to the period of climatologically warmest air 

temperatures. Figure 5.1 shows downscaled historical 

averages for August surface air temperatures and simulated 

annual maximum weekly water temperatures (Tw) for the 

1970–99 (1980s) period (left panel) and for a multimodel 

ensemble average under A1B greenhouse gas emissions for 

2030–2049 (2040s) (right panel). Although air temperatures 

are not the only influence on water temperatures, air temperature can provide an accurate indicator of water temperature in many cases (Mohseni et al. 1998; see Mantua et 

al. [2010] for detailed modeling methods). Under historical 

conditions, August mean surface air temperatures on the 

Olympic Peninsula are below 17 °C everywhere except a 

narrow corridor in the lowlands along Hood Canal. Two of 
44

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 5.1—August mean surface air temperature and maximum 

stream temperature for the Olympic Peninsula. Color shading 

shows mean surface air temperatures for August, and shaded circles show the simulated mean of the annual maximum for weekly 

water temperatures for select locations. Historical air temperature 

and simulated water temperature for the 1980s (1970–99) are in 

the left panel, while a future scenario derived from a multimodel 

average under A1B medium level emissions is shown in the right 

panel. Olympic National Park and Olympic National Forest are 

outlined in dark gray. (Adapted from Mantua et al. 2010.)

the three water temperature sites on the Olympic Peninsula 

have Tw <17 °C, while one has Tw approximately 20 °C. For 

the 2040s scenario, the encroachment of summertime air 

temperatures with Ta >20 °C becomes the norm for western 

Washington’s lowlands, and for this period only, the higher 

elevations of the Cascades and Olympics have temperatures 

like those characteristic of the western Washington lowlands in the 1980s. 

For A1B emissions scenarios in the 2020s, annual 

maximum Tw at most stations on the Olympic Peninsula is 

projected to rise less than 1 °C, but by the 2080s, several 

stations on the Olympic Peninsula warm by 1 to 2 °C (not 

shown). Water temperatures projected under the A1B emissions scenarios become progressively warmer than those 

projected under the B1 emissions, and by the 2080s the 

differences are approximately 1 °C (projected summertime 

air temperatures under A1B emissions are, on average, 1.8 

°C warmer than those under B1 emissions for the 2080s).

Increases in stream temperature with climate change 

are likely to differ across landscapes. Locations that currently experience high summer air temperatures are likely 

to have the largest increases in water temperature (ISAB 

2007). A study by Daly et al. (2009) suggests that complex 

patterns of temperature change may occur in locations with 

complex terrain; locations with cold air drainage and pooling will likely experience the lowest temperature increases, 

whereas exposed hill slope and ridge top locations will 

likely experience the highest temperature increases. In the 

John Day River basin in northeastern Oregon, Torgersen 

et al. (1999) found water temperatures to be warmest in 

downstream (low-elevation) stream reaches and in locations 

where the cooling effects of subsurface flow are less apparent. These and locations with channel conditions prone to 

heating (wide, shallow, lack of riparian vegetation) (Crozier 

and Zabel 2006) are likely to experience further warming 

with climate change. Changes in water temperature will 

also differ with hydrologic changes. Decreases in summer 

low flows will make streams more susceptible to increased 

air temperature, and earlier snowmelt will result in warming beginning earlier in the year in basins affected by 

snowmelt (ISAB 2007). 

Climate Change Effects on Snowpack and 

Streamflow

Figure 5.2 classifies runoff in Washington’s watersheds 

(at the level 4 hydrologic unit code) for historic and future 

periods as either snowmelt dominant, transient, or rain 

dominant based on their basin-averaged ratio of simulated 

April 1st snowpack to their October to March total precipitation (Elsner et al. 2010). Rain-dominant basins (where the 

ratio is <0.1) are the most common type on the Olympic 

Peninsula (for the 1980s). There is one transient basin 

(mixed rain and snow basin where the ratio lies between 

0.1 and 0.4) in the northeastern portion of the Olympic 

Peninsula, and there are no snowmelt basins (where this 

ratio >0.4 for the 1980s). As projected climate warms, the 

historically transient basin on the Olympic Peninsula is 

projected to become rain dominant by the 2040s under the 

A1B emissions scenario, and by the 2080s under the B1 

emissions scenarios.

The recently completed Hydrologic Climate Change 

Scenarios for the Pacific Northwest Columbia River Basin 

and Coastal Drainages project (project homepage http://
45

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 5.2—Watershed classification in Washington state for 

simulated runoff in the historic period (1970–99) and future 

periods (2020s, 2040s, and 2080s). Simulations that use A1B 

emissions are in the lower three rows of the left column, and those 

that use B1 emissions scenarios are in the lower three rows of the 

right column. [SWE = snow water equivalent.] (Adapted from 

Elsner et al. 2010.) 

www.hydro.washington.edu/2860) includes future snowpack and streamflow scenarios from 10 global climate 

models under two greenhouse gas emission scenarios for 

the 21st century. A sample of hydrologic model output for 

select watersheds on the Olympic Peninsula is provided in 

figures 4.2 to 4.7 in chapter 4. The magnitude and frequency 

of flooding are predicted to increase for watersheds on 

the Olympic Peninsula, most dramatically in the months 

of December and January, and most dramatically for the 

coldest basins that in the late 20th century typically collected significant amounts of snow in their upper reaches. 

Hydrologic models indicate that warming trends will 

substantially reduce seasonal snowpack on the Olympic 

Peninsula (Elsner et al. 2010), thereby decreasing the risk of 

springtime snowmelt-driven floods. 

The shifts in flood risk in each basin tend to monotonically increase or decrease through time. In other words, the 

increases or decreases in flooding magnitude of each basin 

generally become larger, with the same sign from the 2020s 

to the 2080s, with the greatest impacts occurring at the end 

of the 21st century. Emissions scenarios also play a strong 

role in the rate of change in flooding magnitudes, with the 

changes for A1B emissions in the 2040s being similar to 

those for the B1 emissions in the 2080s. 

Reductions in the magnitude of summer low flows are 

projected to be widespread for the Olympic Peninsula’s 

rain-dominant and transient runoff river basins (not shown). 

Future estimates of the annual average low flow magnitude 

(7Q10, which is the 7-day average low flow magnitude with 

a 10-year return interval) are projected to perhaps increase 

by a few percentage points or decline by up to 50 percent, 

with most climate model scenarios leading to declines by 

the 2080s under both the A1B and B1 emissions scenarios. 

As indicated by the simulated runoff graphs shown in 

figures 4.2 through 4.7, the duration of the summer low 

flow period is also projected to increase significantly in all 

but the most rain-dominant watersheds, which include the 

Skokomish, Queets, and Hoh watersheds.

Projected Effects of Altered Hydrology on Olympic 

Peninsula Salmon, Steelhead, and Bull Trout

Waples et al. (2008) noted that existing salmon populations should have the capacity for responding to habitat 

changes that fall within the bounds of historical disturbance 

regimes, specifically episodic disturbances that most often 

impact relatively small habitat patches relative to the spatial 

extent of evolutionarily significant population groups that 

are typically influenced by regional physiographic features. 

It remains an open question whether present-day salmonid 

fish populations on the Olympic Peninsula can adapt 

(either through phenological, phenotypic, or evolutionary 

responses) at rates required to deal with the combination of 

anthropogenic climate change and other habitat and ecosystem changes that will come in the next century (Crozier et 

al. 2008). 
46

GENERAL TECHNICAL REPORT PNW-GTR-844

Our assessment of future stream temperature, streamflow changes, and limiting factors indicates widespread 

declines in the quality and quantity of freshwater habitat 

for many Olympic Peninsula salmon, steelhead, bull trout, 

and resident fish populations, unless they are able to quickly 

adapt to changing habitat conditions. Increases in stream 

temperature alone point to significant increases in thermal 

stress (fig. 5.1) for Washington’s salmonid fish populations 

having a stream-type life history that puts them in freshwater during summer for spawning migrations, spawning, 

rearing, or seaward smolt migrations. Temperature impacts 

on adult spawning migrations are projected to be most 

severe for stocks having summertime migrations. These 

include summer-run coho salmon in the Sol Duc watershed, 

and summer run chum salmon in several Hood Canal 

streams. Increased stream temperatures pose risks to the 

quality and quantity of favorable rearing habitat for streamtype chinook and coho salmon and steelhead (summer and 

winter run) because these stocks spend at least one summer (and for steelhead typically two summers) rearing in 

freshwater. 

Increased stream temperatures on the Olympic Peninsula will also affect bull trout. This species, which is listed 

as threatened under the federal Endangered Species Act 

(ESA) (ESA 1973), is highly sensitive to stream temperature, generally requiring stream temperatures below 15 °C 

(USFWS 2004). There are six core areas of spawning bull 

trout on the peninsula (USFWS 2004). Unlike other areas 

of their range, bull trout on the peninsula are found only 

within the anadromous portion of watersheds, below anadromous migration barriers. Increased stream temperatures 

and reduced summer streamflows could particularly affect 

bull trout by reducing the quantity and quality of rearing 

habitat. 

In addition to increased stream temperatures, reductions in the volume of summer/fall low flows in transient 

and rain-dominated basins might also affect summer-run 

steelhead migration and reduce the availability of spawning 

habitat for bull trout and salmon populations that spawn 

early in the fall (e.g., Healey 1991). Predicted increases in 

the intensity and frequency of winter flooding will likely 

negatively impact the egg-to-fry survival rates (table 5.1) for 

pink, chum, sockeye, chinook, and coho salmon and bull 

trout owing to an increased intensity and frequency of redd 

and egg scouring. However, the effects of scour will differ, 

in part, by channel type and location in the stream network. 

Confined streams that are high in the network will likely 

be most susceptible to scour, which will likely impact the 

steelhead and bull trout that inhabit them. Lower gradient 

streams in unconfined settings, such as those typically 

inhabited by chinook, will likely be least vulnerable to 

scour. In addition, the impact of increasing winter flooding 

will likely differ across species or populations because redd 

depth is a function of fish size (deeper redds will be less 

vulnerable to scouring and the deposition of fine sediments). 

Parr-to-smolt survival rates may be reduced for coho 

and stream-type chinook salmon and steelhead with climate 

change because increases in peak flows can reduce the 

availability of slow-water habitats and cause increases in the 

displacement of rearing juveniles downstream of preferred 

habitats (table 5.1). However, the effects of increased peak 

flows will depend on the particular geomorphic setting and 

on whether the fry will have emerged before or at the time 

of the high flows. The effects of increased peak flows will 

be more pronounced in constrained reaches (i.e., narrow 

valleys and higher gradient streams), which are used by 

steelhead and bull trout for spawning, than in unconstrained 

reaches (i.e., wide valleys and lower gradient streams), 

which are used by coho and chinook. In the latter, the fish 

may be able to move to off-channel areas that would not be 

available at normal flows. Displacement could be a problem 

in the former situation. Displacement could be exacerbated 

if fish emerge earlier because of elevated winter water 

temperatures. The effects of high flows may be minimal 

for some fish, such as winter steelhead that spawn after 

peak flow events. However, for some species, reductions in 

springtime snowmelt may negatively impact the success of 

smolt migrations from snowmelt-dominant streams where 

seaward migration timing has evolved to match the timing 

of peak snowmelt flows.

Summer chum salmon stocks in Hood Canal are listed 

as threatened under the ESA. These populations have a 

unique life history that makes them especially vulnerable 

to the impacts of climate change. Adults return to spawn in 
47

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 5.1—Salmon life cycle stages and climate change effects that will likely impact each salmon 

life cycle stage

Climate change effects that will likely 

Salmon life cycle stage impact salmon life cycle stage

Eggs in stream gravel; hatch in 1 to 3 months

Alevins in stream gravel; 1 to 5 months

Fry emerge in spring or summer

Juvenile fish in freshwater; a few days to 

 4 years depending on species and locality

Smolt migration to ocean; usually in spring 

 and early summer

Fish in ocean; 1 to 4 years

Migration to spawning grounds; timing 

 depends on species and race

Fish spawning in freshwater stream

Increased winter flooding and mean flows; warmer water

Increased winter flooding and mean flows; warmer water

Increased winter flooding and mean flows; warmer water 

Warmer water and lower streamflows in summer; increased

 winter flooding in transient basins

Warmer water and lower streamflows in summer; increased

 winter flooding in transient basins

Sea level rise; altered river discharge

Warmer water and lower streamflow

Warmer water and lower streamflow

small shallow streams in late summer, and eggs incubate 

in the fall and early winter before fry migrate to sea in 

late winter. The predicted climate change effects for the 

low-elevation Hood Canal streams used by summer chum 

include multiple negative impacts stemming from warmer 

water temperatures and reduced streamflow in summer. 

It is possible that climate-induced warming in winter 

and spring will lead to earlier and perhaps longer growing 

seasons, increased aquatic food web productivity, and more 

rapid juvenile salmon growth and development rates that 

benefit parts of the freshwater life cycle of the Olympic Peninsula’s salmon and steelhead (Schindler and Rogers 2009). 

This could potentially increase the full life cycle productivity for salmon populations if the positive impacts outweigh 

the negative impacts described above. For example, in 

watersheds that are currently minimally affected by snowmelt (rain-dominant basins), the changes in the timing of 

streamflow with climate change will likely be minimal. 

Thus, without substantial increases in winter flooding and 

reductions in summer low flows, increased winter stream 

temperatures could have a net positive impact on salmon 

in these watershed types, depending on the magnitude of 

late-spring through fall stream temperature changes. 

Potential benefits of warmer stream temperatures for 

coho salmon were shown in studies of clearcut logging 

impacts in the Carnation Creek watershed of Vancouver 

Island, British Columbia (Holtby 1988). Logging in this 

watershed led to stream warming of 0.7 °C in December and 

over 3 °C in August, which in turn contributed to positive 

growth responses in juvenile coho salmon, accelerations 

in the freshwater component of coho salmon life histories, 

and increases in overwinter survival rates for rearing 

juveniles. However, these changes in freshwater development appear to have been offset by reduced marine survival 

rates associated with earlier smolt migrations to the ocean 

(because of warmer spring stream temperatures) that may 

have been mismatched to the optimal timing for ocean prey 

availability and predator avoidance. Holtby (1988) estimated 

that warmer stream temperatures increased the full life 

cycle coho production in this system by about 9 percent. 

Modeling from the same study system suggested that effects 

of warmer stream temperatures as a result of logging may 

be greater on chum than coho salmon (Holtby and Scrivener 

1989).

Because of the earlier timing of snowmelt and 

increased evaporation, some of the Olympic Peninsula’s 

river basins (including the Elwha and Dungeness) are 

projected to experience reduced streamflow in summer and 

early fall that results in an extended period of summer low 

flows, and many basins are also projected to have substantially lower base flows. In combination with increased summertime stream temperatures, reduced summertime flow is 

likely to limit rearing habitat for salmon with stream-type 
48

GENERAL TECHNICAL REPORT PNW-GTR-844

life histories (wherein juveniles rear in freshwater for 1 or 

more years) and increase mortality rates during spawning 

migrations for summer-run adults (table 5.1).

Fish Habitat Management at Olympic 

National Forest and Olympic National Park

This section provides information on the biogeographic 

context, guiding policies and legislation, and primary 

activities in fish habitat management at Olympic National 

Forest (ONF) and Olympic National Park (ONP), including 

(1) the context in which ONF and ONP manage fish habitat, 

(2) the guidance and constraints on fish habitat management 

at ONF and ONP, and (3) the primary issues around and 

activities currently conducted in fish habitat management 

at ONF and ONP. This information, coupled with the likely 

impacts of climate change on fish on the Olympic Peninsula, 

provides a basis on which to develop climate change adaptation options for fish habitat management at ONF and ONP. 

Biogeographic Context

The ONF contains portions of 17 major drainages on the 

Olympic Peninsula and manages about 560 km of anadromous fish streams and another 685 km of streams that 

provide habitat for resident fish populations. At least 40 

small alpine lakes and two reservoirs exist on the forest.

The streams, rivers, and lakes at ONF provide habitat 

for seven anadromous fish species including chinook, coho, 

chum, and pink salmon; steelhead trout; sea-run cutthroat 

trout; and bull trout. Resident salmonids include cutthroat 

trout and rainbow trout. Four of the fish stocks on the forest 

are listed as threatened under the ESA: Puget Sound chinook, Puget Sound steelhead, Hood Canal summer chum, 

and bull trout. 

Rainfall, geology, and management legacies present 

some challenges for fish habitat management at ONF. Some 

parts of the Olympic Peninsula receive more than 5 m of 

rain per year. Long, steep slopes, underlying geology, and 

heavy rainfall result in unstable ground on some parts of 

ONF. The ONF also has an extensive legacy of timber 

harvest. About 50 percent of the suitable land base was 

harvested between the 1960s and the mid 1990s. Over 3500 

km of forest roads initially built for timber harvest remain 

on the forest road network. Unstable slopes combined with 

an extensive road network can result in sedimentation and 

aquatic habitat degradation.

The ONP contains over 5600 km of rivers and streams 

that support 70 unique salmonid stocks as well as numerous nonsalmonid species. The park also includes two large 

natural lakes and over 300 smaller alpine lakes and lower 

elevation ponds. In addition to the federally listed fish 

stocks at ONF, ONP also has the Lake Ozette sockeye fish 

stock, which is listed as threatened under the ESA. 

There are 225 km of roads located in the park, along 

with many visitor facilities (visitors’ centers, campgrounds, 

and way points). With the exception of the Hurricane Ridge 

Road and Deer Park Roads that access alpine areas, the 

park’s road system and many visitor facilities occur within 

the flood plains of the park’s major river systems (Elwha, 

Sol Duc, Hoh, Queets, Quinault, and North Fork Skokomish); segments of these roads lie immediately adjacent to 

the rivers. Maintenance and repair activities associated with 

these road systems constitute (historically) a major impact 

to fish and aquatic communities.

Guiding Policies and Legislation

The ONF Land and Resource Management Plan (LRMP) 

(USFS 1990) as amended by the 1994 Northwest Forest Plan 

(USDA and USDI 1994) guides current management activities at ONF. A key component of the plan is the Aquatic 

Conservation Strategy (ACS), which includes nine objectives for maintaining and restoring watershed processes and 

functions. To be consistent with the LRMP and the ACS, all 

management activities at ONF must maintain or help restore 

watershed conditions. In line with these broader mandates, the goal of fish habitat management at ONF is to 

maintain or restore watershed processes and functions and 

provide diverse, resilient fish habitats capable of supporting 

populations of native fishes over the long term.

At ONP, fish habitat management programs and decisions are guided by the National Park Service Management 

Policies (NPS 2006), as well as the ONP General Management Plan (GMP) (NPS 2008), the ONP Backcountry Management Plan (NPS 1980), and the ONP Superintendant’s 

Compendium. The park’s planning and compliance process 
49

Adapting to Climate Change at Olympic National Forest and Olympic National Park

guides preservation of fish habitat within ONP by prescribing measures to prevent or minimize the impact of all park 

management activities. Usually, particularly within wilderness areas, limiting the construction of new facilities within 

flood plains avoids impacts to fish habitat. The park’s GMP 

(NPS 2008) calls for potential relocation of existing roads, 

campgrounds, or other visitor facilities out of flood plains 

as feasible, or when a road or facility cannot be relocated, 

directs that measures to protect and maintain the facility 

must be designed to minimize the effect on fish habitat to 

the extent possible. The ONP recently evaluated a variety of 

road and facility hazards within the park, and will evaluate 

protection measures designed to be more environmentally 

sensitive than traditional engineered designs.

Primary Fish Habitat Management Issues and 

Activities

Olympic National Forest—

The primary management issues for fish and fish habitat at 

ONF include:

Sedimentation from forest roads

Road-related landslides can cause sedimentation in streams 

(Fredriksen 1970, Harr and Nichols 1993) and influence fish 

habitat (Harr and Nichols 1993). Road-related sedimentation 

is a major issue impacting fish habitat at ONF. In response, 

ONF decommissions unneeded roads, and removes sidecast 

material and improves drainage on the remaining roads.

In 2000, the forest completed a Road Management 

Strategy (RMS). This geographic information system based 

analysis evaluated the risk each road segment presented to 

fish habitat and water quality based on its location, geomorphic factors, distance to stream channels, and number 

of stream crossings. About 34 percent of the roads on the 

forest are rated as “high” or “very high” risk to aquatic 

resources.

In 2003, the forest used the new aquatic risk information, coupled with an assessment of the access needs and 

anticipated future funding levels, to revise the Access 

and Travel Management (ATM) Plan. The plan proposes 

decommissioning of over 1270 km of forest roads, or about 

one-third of the road system. The ATM and aquatic risk 

information helps to prioritize road treatment locations as 

funding becomes available. In previous actions and following the new ATM plan, ONF decommissioned about 700 

km of road since 1990.

Fish passage and culverts

Currently, 77 culverts block fish passage on the forest 

including five anadromous sites blocking a total of 13 km 

of anadromous fish habitat, 16 high-priority resident sites 

blocking more than 1.6 km of resident fish habitat each, 14 

moderate-priority resident sites blocking between 0.8 and 

1.6 km of resident fish habitat each, and 42 low-priority 

resident sites that block less than 0.8 km of resident fish 

habitat each. Since 2002, forest managers completed 18 fish 

passage barrier correction projects, restoring access to 39 

km of fish habitat. Anadromous barriers are the top priority 

for correction. Biologists prioritize resident barriers based 

on the amount of fish habitat that would be reconnected.

Instream large wood

Past stream clearing and splash damming activities at ONF 

removed large wood from many stream channels. Placing large wood in key stream reaches restores watershed 

processes and functions and improves fish habitat by 

providing structure, creating cover, scouring pools, and 

trapping spawning gravels. The forest completed numerous 

small-scale large-wood placement projects in the past and 

is planning an extensive logjam construction project on the 

South Fork Skokomish River in 2010. Increasing landslides 

with climate change (see chapter 4) could also potentially 

increase upslope sources of wood to streams. 

Riparian vegetation

Logging activities in the past removed conifers from many 

streambanks at ONF. Conifers regenerated in some riparian 

areas, but many riparian corridors have few conifers to provide large wood to streams. In these areas, reestablishment 

of conifers will help to provide a long-term source of large 

wood in channels. However, these projects require long 

commitments over time, are costly, and are consequently 

not a high priority for forest managers. 

Nutrient supplementation

Marine-derived nutrients carried back into anadromous 

streams by returning adult salmon carcasses are a key 
50

GENERAL TECHNICAL REPORT PNW-GTR-844

element in the productivity of many streams (Helfield and 

Naiman 2001, Naiman et al. 2002). Extirpation of salmon 

stocks and extremely low escapements of anadromous fish 

have likely reduced potential productivity in forest streams. 

Supplementing nutrient supplies, either by distributing 

salmon carcasses or adding slow-release fertilizers, has 

the potential to increase the numbers and condition of 

juvenile salmon, steelhead, and bull trout in forest streams. 

Although carcass supplementation has not yet been demonstrated to improve salmonid productivity or riparian 

vegetation growth on the Olympic Peninsula, Cederholm 

et al. (1989) showed that carcasses are utilized by a large 

number of wildlife species. The forest has been distributing 

surplus chum salmon carcasses throughout the upper South 

Fork Skokomish watershed. The Pacific Salmon Coalition distributes salmon carcasses throughout the Quileute 

system. 

Invasive species

Some exotic species such as Japanese knotweed are considered invasive owing to their potential to outcompete native 

vegetation. Invasive infestations in riparian areas reduce 

future sources of large wood by outcompeting tree species 

and change the terrestrial food inputs into streams. Removal 

and control of priority invasive weed species helps to 

maintain riparian function. There are also public education 

efforts for aquatic invasive species. However, ONF has not 

identified aquatic species on the forest that warrant intensive control or monitoring efforts. 

Olympic National Park—

At ONP, fish habitat management activities fall into three 

general categories: (1) habitat preservation, (2) habitat 

restoration, and (3) management planning. Within the 

past 5 years, the park has conducted several restoration 

projects, including removal or replacement of numerous 

undersized culverts that were partial or complete barriers 

to fish migration. A significant habitat restoration project 

is the upcoming removal of two dams from the Elwha 

River. However, with the exception of the Elwha project, 

habitat restoration within ONP is opportunistic as opposed 

to strategic, and has no sustained funding source. Park 

biologists work to rectify this through numerous activities, 

including participation in various salmon recovery forums, 

interagency planning for watershed water use strategies, 

cooperation with the National Oceanic and Atmospheric 

Administration National Marine Fisheries Service and local 

tribes to develop and implement ESA recovery plans, and 

development of a prioritized list of culverts targeted for 

replacement.

It will be critical for ONP to consider climate change 

in the future management of fish habitat. Whether management activities involve protection, restoration, or unknown 

and undecided manipulative actions, the changing climate 

will dictate measures needed to preserve “unimpaired” the 

fisheries resources of the park. Although today’s conditions 

will change, through careful consideration and evaluation 

of the effects of climate change on the aquatic environment, 

adaptation strategies may help to sustain processes that 

shape and maintain viable aquatic ecosystems. 

Climate Change Adaptation in Fish and 

Fish Habitat Management at Olympic 

National Forest and Olympic National Park 

Process Used in Development of Adaptation 

Strategies for Fish Management

To develop adaptation strategies and action items for fish 

management on federal lands on the Olympic Peninsula, 

scientists, managers, and other stakeholders collaborated 

and shared information and perspectives at two workshops. 

In November 2009, a workshop on “Climate Change 

Impacts on Olympic Peninsula Salmon” provided scientific 

information to a broad audience of stakeholders regarding 

vulnerabilities of aquatic habitats and salmonids on the 

Olympic Peninsula under a changing climate. Twelve scientists spoke on a variety of topics, including scenarios for 

the Olympic Peninsula’s climate and landscape in the 21st

century, climate change effects on freshwater aquatic ecosystems, climate change effects on coastal marine systems, 

and planning for climate change (presentations are available 

online at: http://www.fs.fed.us/ccrc/video/olympic_climate_

change.shtml). Panel discussions followed the presentations 

in each topic area, and the workshop concluded with an 

open discussion focused on key vulnerabilities and adaptation strategies for aquatic ecosystems on the peninsula. The 
51

Adapting to Climate Change at Olympic National Forest and Olympic National Park

nearly 100 participants included representatives from ONF, 

ONP, and a variety of state and federal natural resource 

agencies, watershed organizations, and tribes.

A subsequent, smaller workshop focused on developing 

adaptation strategies and action items for fish management 

at ONF and ONP. Participants in this second workshop 

included ONF and ONP natural resources staff and scientists from the Forest Service Pacific Northwest Research 

Station (PNW) and the University of Washington Climate 

Impacts Group. Objectives of the workshop were to (1) 

use the latest scientific information on climate change 

and effects on fish to identify adaptation actions for fish 

management that should be taken by ONF and ONP in the 

short term (over 1 to 5 years), (2) identify priorities and 

priority areas (e.g., key watersheds, stream reaches, and 

species) for climate change adaptation on the forest and 

park, and (3) identify policy issues and regulatory barriers 

to climate change adaptation in fisheries and fish habitat 

management. The workshop began with a presentation 

from Nathan Mantua on key aquatic vulnerabilities with 

climate change on the Olympic Peninsula. Fish biologists 

Patrick Crain (ONP) and Robert Metzger (ONF) provided 

presentations on fish habitat management at ONP and ONF, 

respectively. Gordon Reeves (PNW) also gave a presentation on the potential utility of the NetMap tool (Benda et al. 

2009; http://www.netmaptools.org) in adapting fish habitat 

management to climate change. A facilitated discussion on 

adaptation options for fisheries and fish habitat management 

with climate change followed. A description of potential 

adaptation strategies and action items appears in the section below, with a summary in table 5.2. See box 5.1 for a 

general summary of projected climate change effects on fish 

on the peninsula and related adaptation strategies for fish 

habitat management at ONF and ONP. 

Adaptation Strategies and Actions for Hatcheries 

and Harvest

Olympic National Park has exclusive federal jurisdiction 

with the authority to determine regulations for sport fishing 

and recreational shellfish harvest in the park, and thus can 

consider resilience to climate change among other factors 

used to set regulations. For example, it is anticipated that 

Sol Duc summer coho will be affected by climate change. 

Although the summer coho in the Sol Duc River is not a 

federally listed population, the population is known by the 

park to be depressed. Current park regulations for the Sol 

Duc River allow for a catch-and-release fishery from June 

1 to October 31, with a minor area closure associated with a 

summer coho prespawning staging area below the Salmon 

Cascades. However, minor but measurable mortality occurs 

with all catch-and-release fisheries. Therefore, in the face 

of climate change, it may be appropriate for the park to 

consider a complete closure of fisheries in the Sol Duc River 

when summer coho are present to eliminate all harvest 

mortality and thus help the population remain viable. 

As warranted by climate change and associated 

stressors, the park will foster fish population protection 

through recreational harvest management, considering 

potential area or time closures for fish or shellfish as necessary, and protecting any identified cold water refugia (using 

stream temperature information or modeling tools such as 

NetMap; Benda et al. 2009; http://www.netmaptools.org; 

and G. Reeves2). Biologists will consider fish life history 

in determining when and where these management actions 

would be most effective. As it does currently, the setting 

of fishing regulations within the park in the future will 

occur in consultation with the state of Washington and the 

affected Olympic Peninsula tribes to ensure that the park’s 

regulations are consistent with, or not in opposition to, fishing regulations set by the state or federal government. 

Besides the authority to manage recreational fisheries 

within the park’s boundaries, there is also National Park 

Service guidance (NPS 2006) for the use of hatcheries 

within the park. National Park Service 2006 Management 

Policies require that, whenever possible, native plants 

and animals should be relied upon to maintain their own 

populations, although management intervention is allowed 

to protect rare, threatened, or endangered species. In these 

2 Reeves, G. 2009. Personal communication. Research fisheries biologist. USDA Forest Service, Pacific Northwest Research Station, 3200 SW Jefferson Way, Corvallis, OR 97331.
52

GENERAL TECHNICAL REPORT PNW-GTR-844

Table 5.2—Current and expected sensitivities of fish to climate change on the Olympic Peninsula, associated 

adaptation strategies and actions for fisheries and fish habitat management at Olympic National Forest (ONF) 

and Olympic National Park (ONP)a

Current and expected sensitivities

Novel ecosystem response to shifting climate 

and hydrology 

Changes in fish distribution, population size, 

and viability

Changes in timing of fish life history events

Changes in habitat quantity and quality

Increase in culvert failures, fill-slope failures, 

stream adjacent road failures, and encroachment from stream-adjacent road segments

Greater difficulty disconnecting roads from 

stream channels

Major changes in quantity and timing of 

streamflow in transitional watersheds 

Increased erosion and sediment delivery to 

channels.

Increased thermal stress on cold-wateradapted fish species

Decreased fish numbers owing to reductions 

in suitable habitat and productivity

Increased risk of disease introduction from 

hatchery fish

Increased disease virulence with warmer 

stream temperatures

Adaptation strategies and actions

• Shift to a new paradigm in fish habitat management that recognizes 

that pre-existing channel conditions may no longer be an accurate 

representation of the potential state. 

• Incorporate climate change into the ONF Strategic Plan. 

• Implement strategic monitoring; build from existing monitoring 

programs.

• Use tools such as NetMap to identify areas most likely to exhibit a 

climate change signal.

• Monitor restoration projects to determine strengths and weaknesses of 

existing projects, and improve design of future restoration 

projects.

• Look for early indications of change to determine how quickly some of 

the climate-related changes are occurring, and use that information to 

adjust management priorities. 

• Implement habitat restoration projects that focus on re-creating 

watershed processes and functions and that create diverse, resilient 

habitat.

• Decommission unneeded roads.

• Remove sidecast, improve drainage, and increase culvert sizing on 

remaining roads.

• Relocate stream-adjacent roads.

• Design more resilient stream crossing structures.

• Make road and culvert designs more conservative in transitional 

watersheds to accommodate expected changes.

• Consider adding large wood to small headwater channels to restore 

natural sediment routing (ONF lands).

• Consider thinning in steep landslide-prone areas to accelerate 

development of large wood inputs to streams (ONF lands).

• Limit mortality associated with recreational fishing through time and 

area closures as necessary.

• Encourage implementation of Hatchery Scientific Review Group 

recommendations for hatchery reforms.

• Follow 2006 National Park Service policies regarding the planting of 

hatchery fish within parks.

• Control spread of exotic species.
53

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 5.2—Current and expected sensitivities of fish to climate change on the Olympic Peninsula, associated 

adaptation strategies and actions for fisheries and fish habitat management at Olympic National Forest (ONF) 

and Olympic National Park (ONP)a (continued)

Current and expected sensitivities

Decline in native fish populations owing to 

 increased competition from exotic species

Increased spread of aquatic invasive species

Loss of cold water refugia for cold-wateradapted fish species 

Decrease in area of headwater streams.

Decrease in habitat quantity and connectivity 

for species that use headwater streams.

Increased sensitivity for species that spawn

in late summer (e.g., summer chum, summer

coho, spring chinook)

a Sensitivities are based on projected climate change effects on the Olympic Peninsula, including increased winter precipitation and runoff, more 

precipitation falling as rain rather than snow, increased storm intensity, greater winter and spring streamflows in some types of watersheds, increased 

flood frequency and magnitude in some types of watersheds, elevation shifts in transition (rain-on-snow) zones, reduced summer streamflows, and 

increased stream temperatures.

Adaptation strategies and actions

• Monitor to detect increases in invasive populations; initiate control 

measures aggressively.

• Educate the public about measures to prevent the spread of invasive 

species.

• Focus habitat protection and restoration efforts on existing wild fish 

strongholds and streams that are less influenced by hatcheries.

• Identify and protect cold water refugia.

• Continue to correct culvert fish passage barriers.

• Consider re-prioritizing culvert fish barrier correction projects. 

• Restore habitat in degraded headwater streams that are expected to 

retain adequate summer streamflow (ONF).

• Limit mortality associated with recreational fishing through time and 

area closures as necessary.

cases, animals (including fish) can be subjected to a captive 

breeding program (hatchery) to maintain or increase their 

abundance. However, the park must follow all planning 

procedures and provide for public comment and review 

before initiating such a program. In the future, this review 

will include an analysis of the appropriateness of management intervention in the face of climate change.

Olympic National Forest does not have jurisdiction 

over fishing regulations, seasons, or closures on national 

forest lands, nor do they control hatchery supplementation 

in streams and rivers that flow through the national forest. Authority for these activities resides solely with the 

state of Washington and the Olympic Peninsula tribes as 

co-managers. As in the past, ONF will continue to work 

with the state of Washington and the tribes to help identify 

and promote regulations needed to limit harvest mortality 

on high-priority species in key areas. The ONF will also 

continue to work with the co-managers and the National 

Marine Fisheries Service to help evaluate and implement 

hatchery supplementation programs, where necessary, to 

maintain viable populations of high-priority fish species on 

ONF lands. 

Both the forest and park can continue to encourage the 

state, tribes, and U.S. Fish and Wildlife Service to implement the Hatchery Scientific Review Group recommendations (HSRG 2004) for hatchery reforms on the peninsula. 

The intent of these science-based recommendations is to 

redesign hatchery programs to help conserve wild salmon 

and steelhead populations and support sustainable fisheries. 

Implementation of these reforms will likely help salmon on 

the Olympic Peninsula remain viable in the face of climate 

change. 

Adaptation Strategies and Actions for Fish Habitat 

Management

The goal of fish habitat management on ONF and ONP 

is to maintain or restore diverse, resilient habitat capable 

of supporting native fish populations over the long term. 
54

GENERAL TECHNICAL REPORT PNW-GTR-844

climate change, ONF and ONP will emphasize maintaining and reestablishing ecosystem processes and functions, 

considering how past and current management practices 

contribute to current and future habitat conditions. Olympic 

National Forest and ONP will also consider how the magnitude of potential changes in climate and streamflow regimes 

will differ both between and within watersheds and assess 

how anticipated changes in climate will alter future stream 

characteristics. For example, increased frequency and magnitude of high-intensity rainfall events will likely increase 

the number of landslides and debris torrents, thus increasing 

sediment loading and subsequent stream aggradation. 

Numerous management actions can be taken to reduce 

the incidence of human-induced landslides, such as decomRecent habitat restoration efforts have typically attempted 

to maintain or re-create key watershed processes and functions, assuming that doing so would eventually re-create the 

historical river morphology and habitat conditions. Current 

restoration efforts are generally consistent with actions that 

will lead to increased ecosystem resilience under changing climate. However, increased restoration efforts and 

proactive management in priority areas will likely increase 

ecosystem resilience to climate change. Further effort 

will be required to reevaluate priorities in light of climate 

change. 

Preexisting channel conditions and locations may no 

longer be an accurate representation of the potential future 

state of fish habitat. To increase ecosystem resilience to 

Box 5.1—Summary of projected climate change effects on fish on the Olympic Peninsula and related 

adaptation strategies for fish habitat management at Olympic National Forest and Olympic National 

Park. 

• Projected increases in winter peak flows, increases in summer stream temperatures, and lower summer streamflows 

suggest there will be declines in freshwater habitat quality and quantity for salmon, steelhead, bull trout, and 

resident fish on the Olympic Peninsula.

• Climate-induced warming in winter and spring could lead to earlier and perhaps longer growing seasons, increased 

aquatic food web productivity, and more rapid juvenile salmon growth and development rates that benefit parts of 

the freshwater life cycle of the Olympic Peninsula’s salmon and steelhead.

• Climate plays a crucial role in aquatic ecology, but the relative importance of climatic factors is quite different for

different species, and even different populations of the same species. For example, those stocks that typically spend 

extended rearing periods in freshwater are likely to have a greater sensitivity to freshwater habitat changes than 

those that migrate to sea at an earlier age. Effects of climate change will also differ within and across watersheds.

• In the face of climate change, it may be appropriate for the park to consider a complete closure of fisheries in some 

locations when vulnerable fish populations are present to eliminate harvest mortality and thus help the population 

to remain viable.

• Increased restoration efforts, focused on maintaining, reconnecting, and reestablishing ecosystem processes and 

functions, and proactive management in priority areas will likely increase ecosystem resilience to climate change 

at Olympic. National Forest and Olympic National Park.

• On the Olympic National Forest, maintaining and restoring connectivity and fish passage in headwater areas that are 

likely to go dry, and restoring damaged habitat in headwater streams that are expected to retain adequate stream

flows will help maintain viable resident fish populations in as many areas as possible.

• The park and forest will control, to the extent possible, exotic aquatic species, invasive riparian plants, and fish

diseases.

• Protection of cold-water refugia will be critical for many species as summer water temperatures increase. Streams 

with cold-water refugia could be prioritized over streams that are currently warm or are likely to become too warm 

with changing climate.

• Monitoring will also be critical to document current status and detect changes that are occurring with warming 

temperatures, and thus, implementation of strategic monitoring will be important for the forest and park in adapting 

fish habitat management to climate change. Existing monitoring programs can be used as a base to develop more 

extensive programs.
55

Adapting to Climate Change at Olympic National Forest and Olympic National Park

missioning unstable roads, removing sidecast material, and 

increasing the size and number of culverts to reduce the 

potential for plugging or flow diversion. At ONF, erosion 

on hill slopes and in steep headwater stream areas once 

intensively managed for timber production could potentially 

be reduced by adding large wood to channels to reestablish 

the sediment storage and routing function that large wood 

provides in streams. In addition, if trees are left along debris 

flow channels, they will cause the debris flow to behave 

differently and have much different effects on the channel. 

However, because an increased rain:snow ratio will likely 

amplify both natural and human-induced landslides, and 

associated higher runoff will alter the stream channel morphology, management actions are unlikely to fully offset 

climate change effects on erosion and stream morphology. 

Consideration of synergisms among changing processes 

with climate change will also be important. For example, 

summer flows are anticipated to decrease, but increased 

porous sediment deposition associated with winter flooding 

may exacerbate low summer surface flows. Understanding and preparing for these potential synergisms will be 

important in adapting to changing conditions associated 

with climate change.

Roads and associated channel crossings are a major 

issue for fish habitat quality. Many adaptation actions for 

road management discussed in chapter 4 are also relevant to 

adaptation in fish habitat management. For example, roads 

adjacent to streams or the marine environment are particularly susceptible to flood and storm damage and are more 

likely to alter natural ecosystem function through restrictions in channel meanders, acceleration of flow velocity, 

and alteration of large wood recruitment. Thus, whenever 

possible, managers will consider moving roads out of flood 

plains (ONF and ONP) and marine coastal zones (ONP). 

Similarly, undersized channel crossings (either bridges or 

culverts) affect the natural function of stream channels 

through increased channel velocity and associated channel 

degradation, disruption of downstream transport of sediment and large wood, and increased potential for plugging 

and initiating landslides or debris torrents. Therefore, to the 

extent practicable, ONF and ONP will attempt to construct 

any new stream crossings with structures sized to meet the 

needs for natural channel function under flows anticipated 

with climate change. This may require larger structures 

than have been used in the past. Olympic National Forest 

and ONP will continue to remove or replace existing undersized stream crossings with appropriately-sized structures 

as opportunities arise and funding is available (see chapter 

4 for further detail). 

Reduced summer streamflows in headwater tributaries will likely reduce the amount of resident fish habitat 

available in many upper stream reaches during dry periods. 

The magnitude of stream habitat reductions will differ 

from watershed to watershed. Intermittent streamflows may 

increase the importance of providing barrier-free migration 

corridors in the upper watersheds so that resident fish can 

reoccupy intermittent stream reaches when flow returns. 

The ONF currently prioritizes resident fish culvert barrier 

correction projects based on the total amount of habitat that 

would be reconnected. Culvert barrier corrections tend to 

focus on the larger, longer streams first and then up into the 

headwaters. The ONF will continue to correct culvert fish 

passage barriers as funds are available. Considering potential streamflow reductions in small high-gradient resident 

fish streams associated with climate change, ONF may need 

to reconsider how to prioritize removal of culvert barriers to 

facilitate passage of resident fish. 

Increased cooperation and strong partnerships can 

help natural resource agencies and other groups address 

ecosystem stressors and climate change more effectively 

through a shared vision and pooling of resources. Olympic 

National Forest and ONP will increase communication and 

coordination on fisheries research, habitat restoration, and 

monitoring between the park and forest. They will also 

work to increase communication with neighboring tribes, 

the state of Washington, other government entities, and 

local watershed groups on restoration priorities and climate 

change issues, seeking opportunities to collaborate with 

other landowners and managers in priority watersheds. 

Reduced summer streamflows will create challenges in 

meeting adequate instream flows for fish in some watersheds. The city of Port Townsend has already experienced 

problems in meeting their required instream flows for 

summer chum as specified in the Biological Opinion for 
56

GENERAL TECHNICAL REPORT PNW-GTR-844

species and disease will further minimize the spread of 

those factors. 

Olympic National Forest will explore ways to incorporate climate change in the Forest Strategic Plan. The 

Forest Strategic Plan identifies focus areas for restoration 

and areas where projects, such as commercial thinning, 

may achieve multiple objectives. In prioritizing thinning 

activities, increased attention could be given to the positive 

impacts that thinning activities can have on riparian and 

aquatic habitat quality. For example, thinning in high-risk 

landslide-prone areas may help to accelerate the establishment of large trees that provide wood to streams. 

Several fish species, including spring chinook salmon, 

Ozette Lake sockeye salmon, resident trout, bull trout, 

Olympic mudminnow, summer coho salmon, and summer chum salmon, are proposed as potential priorities for 

protection because of their sensitivity to changes in stream 

temperature and hydrology expected with climate change. 

Climate change effects will differ between watersheds, and 

a variety of habitat types and locations will be particularly 

sensitive. These areas can be prioritized for restoration and 

protection. For example, transitional watersheds (which 

receive some precipitation as rain and some precipitation 

as snow) are likely to have the greatest increases in winter 

streamflow with climate change. Thus, road and culvert 

designs on both ONF and ONP could be modified to accommodate expected changes in transitional watersheds. Extent 

of headwater streams will likely be reduced with climate 

change-related changes in hydrology. On ONF, maintaining 

and restoring connectivity and fish passage in headwater 

areas that are likely to go dry, and restoring damaged 

habitat in headwater streams that are expected to retain 

adequate streamflows, will help maintain viable resident 

fish populations in as many areas as possible. Protection 

of cold water refugia will be critical for many species as 

summer water temperatures increase. Streams with cold 

water refugia could be prioritized over streams that are 

currently warm and are likely to become too warm with 

changing climate. Wild fish strongholds, such as the Sol 

Duc, Calawah, and Hoh River watersheds, and streams that 

are less influenced by hatcheries could be prioritized over 

other watersheds for a wide range of actions to help ensure 

their special use permit. The forest will work with the city 

to encourage them to adopt adequate water conservation 

measures and increase efficiency of their delivery systems 

so that the Big Quilcene River water levels do not fall below 

specified levels. The ONF could also review existing water 

withdrawal permits and review how users are withdrawing water from the streams across the forest to provide an 

early warning for fish habitat issues as summer streamflows 

decline.

Owing to resource limitations and differences in 

anticipated climate change effects between watersheds, a 

strategic focus of efforts and use of resources is essential 

to most effectively deal with fish habitat issues related 

to climate change. The ONF and ONP identified some 

general priority actions for adaptation, as well as some 

preliminary priorities for species protection, habitat 

protection, and monitoring. One general priority for ONF 

and ONP is to control, to the extent possible, exotic aquatic 

species, invasive riparian plants, and fish diseases. Many 

exotic fish species introduced to the Pacific Northwest are 

well-suited to warmer water temperatures (e.g., American 

shad, bass, perch, channel catfish, etc.). American shad 

is an Atlantic Ocean species that prefers slightly warmer 

waters than salmon. Populations of American shad in the 

Columbia River have increased substantially in the last 

several decades and are likely competing with native fishes 

for habitat and food resources during the summer and fall 

(Petersen et al. 2003). Invasive New Zealand mud snails and 

zebra mussels occur in other parts of Washington. Several 

knotweed species (especially Japanese knotweed) currently 

thrive in some watersheds on the peninsula. Detecting the 

presence of, or increases in, invasive species populations 

requires monitoring and prompt action to effectively control 

or eliminate them. Preventing the spread of exotic fish and 

shellfish and keeping stream temperatures as low as possible through shading will help to keep the potential spread 

of fish disease to a minimum, because exotic species may 

spread diseases to native fish and diseases become more 

virulent with increasing stream temperatures. Ensuring that 

stocked fish meet health guidelines will also help to control 

disease spread. Finally, educating the public about invasive 
57

Adapting to Climate Change at Olympic National Forest and Olympic National Park

continued viability of wild fish populations in the face of 

climate change. 

Monitoring will be critical to document current status 

and detect changes that are occurring with warming temperatures, and thus, implementation of strategic monitoring 

will be important for ONF and ONP in adapting to climate 

change. Olympic National Park has a long-term ecological 

monitoring program that can be used as a foundation for a 

more extensive monitoring program designed to interpret 

effects of climate change on fish populations in both fresh 

and salt water areas of the Olympic Peninsula. Tools such 

as NetMap (Benda et al. 2009; http://www.netmaptools.

org) can also be used to identify areas that are most likely to 

exhibit a climate change signal. Finally, monitoring of restoration projects (e.g., culvert fish passage corrections, road 

decommissioning, engineered logjams, and the Elwha dam 

removal) will continue to be key in determining strengths 

and weaknesses of existing projects, and improving design 

of future restoration projects. 

Priorities for monitoring at ONF and ONP include 

effects of changing climate on fish life history (e.g., emergence timing, and fitness of juvenile fish over the course of 

a growing season), which will be important in determining 

how climate change is influencing fish on the peninsula. 

Collection of otoliths could help identify changes in life 

history patterns. Monitoring of habitat loss, particularly 

in headwaters and at higher elevations, will also help to 

determine what types and how fast habitat is being lost so 

that management activities can be tailored accordingly. 

Challenges and Future Directions in Adaptation in 

Fish and Fish Habitat Management

Clear actions can be taken by ONF and ONP to adapt to 

climate change. However, implementation of adaptation in 

fish and fish habitat management also faces some challenges. As noted in chapter 4, the predominant Emergency 

Relief for Federally Owned Roads Program policy of 

replacing existing infrastructure with the same infrastructure after a failure makes it difficult for ONF and ONP 

to improve infrastructure to meet current standards and 

accommodate effects of climate change. Similarly, restrictions on activities in wilderness areas sometimes prevent 

both agencies from being able to move high-risk roads out 

of flood plains without Congressional action. Both ONF 

and ONP have limited funding for activities that would 

contribute to adaptation. Other state and federal policies 

may become limiting in the future. For example, the state of 

Washington has historically overallocated water, although 

the full allocated rights have not yet been used. New water 

rights may be allocated based on existing summer flows and 

channel conditions, which are likely to change in the future. 

At the federal level, there is no clear pathway to bring 

climate change information into Endangered Species Act 

[ESA 1973] consultations, National Environmental Policy 

Act (1969) analyses, or Clean Water Act (1977) degraded 

waterbody designations. Olympic National Forest and ONP 

will communicate these challenges to state and federal 

decisionmakers and seek solutions that will help overcome 

these challenges and facilitate climate change adaptation. 

Olympic National Forest and ONP may also need to 

initiate research and explore new types of actions to adapt 

fisheries and fish habitat management to climate change. 

For example, more information will be needed on how the 

effects of climate change differ across the landscape, and 

an understanding of this variation will be a key factor in the 

development and implementation of new adaptive actions. 

It is possible that forest structure and composition could 

be managed to reduce evapotranspiration and maximize 

water retention and summer base flow. Stand structure 

could be manipulated to retain snow, and it is possible that 

forest structural conditions could be managed to promote 

increased fog drip. Determining whether these and other 

potential actions could help ONF and ONP adapt to climate 

change will require experimentation, monitoring, and 

feedback to management. 

Acknowledgments

We thank the speakers who participated in the Science 

Day on climate change and fish on the Olympic Peninsula 

including Jeremy Littell and Amy Snover (University 

of Washington Climate Impacts Group), Gordie Reeves 

and Pete Bisson (U.S. Forest Service, Pacific Northwest 

Research Station), Dan Isaak (U.S. Forest Service, Rocky 

Mountain Research Station, Aquatic Sciences Lab), John 
58

GENERAL TECHNICAL REPORT PNW-GTR-844

McMillan, Ed Casillas, and Krista Bartz (National Oceanographic and Oceanic Administration, Northwest Fisheries 

Science Center), James Winton (U.S. Geological Survey, 

Western Fisheries Research Center), and Brian Winter 

(Olympic National Park). We also thank participants in the 

workshop on adapting fish habitat management to climate 

change including Jeremy Littell and Amy Snover (University of Washington Climate Impacts Group), Gordie Reeves 

and Pete Bisson (U.S. Forest Service, Pacific Northwest 

Research Station), Phil DeCillis and Mark McHenry (Olympic National Forest), and Deborah Konnoff (U.S. Forest 

Service, Pacific Northwest Region). Pete Bisson and Gordie 

Reeves provided helpful reviews of this chapter. 

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physical controls on salmonid spawning location and 

timing. In: Sear, D.; DeVries, P., eds. Salmonid spawning 

habitat in rivers: physical controls, biological responses, 

and approaches to remediation. Symposium 65. 

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W.J. 1989. Fate of coho salmon (Oncorhynchus kisutch) 

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and coastal drainages. http://www.hydro.washington.

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multiple scales: evidence for differential population 

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atmospheric decoupling in complex topography alters 

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spawning migrations. Physiological and Biochemical 

Zoology. 81: 697–708.

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2010).

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(Oncorhynchus tshawytscha). In: Groot, C.; Margolis, 

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Helfield, J.M.; Naiman, R.J. 2001. Effects of salmonderived nitrogen on riparian forest growth and 

implications for stream productivity. Ecology. 

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associated impacts on the coho salmon (Oncorhynchus 

kisutch). Canadian Journal of Fisheries and Aquatic 

Sciences. 45: 502–515.

Holtby, L.B.; Scrivener, J.C. 1989. Observed and 

simulated effects of climatic variability, clear-cut 

logging and fishing on the numbers of chum salmon 

(Oncorhynchus keta) and coho salmon (O. kisutch) 

returning to Carnation Creek, British Columbia. In: 

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habitat alterations on salmonid stocks. Canadian Special 

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62–81.

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and wildlife. http://www.nwcouncil.org/library/isab/

isab2007-2.htm. (12 April 2010).

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change impacts on streamflow extremes and 

summertime stream temperature and their possible 

consequences for freshwater salmon habitat in 

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temperatures. Water Resources Research. 34: 2685–

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J.M. 2002. Pacific salmon, nutrients, and the dynamics 

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management plan, Olympic National Park. Port Angeles, 

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2006. Washington, DC: U.S. Government Printing 

Office. 168 p.

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Park general management plan. Port Angeles, WA: 

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salmonids. Seattle: Washington Sea Grant. 179 p.

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[et al.]. 2003. American shad in the Columbia River. 

American Fisheries Society Symposium. 35: 141–155.

Richter, A.; Kolmes, S.A. 2005. Maximum temperature 

limits for chinook, coho, and chum salmon, and 

steelhead trout in the Pacific Northwest. Reviews in 

Fisheries Science. 13: 23–49. 

Schindler, D.E.; Rogers, L.A. 2009. Responses of 

salmon populations to climate variations in freshwater 

ecosystems. In: Krueger, C.C.; Zimmerman, C.E., eds. 

Pacific salmon: ecology and management of western 

Alaska’s populations. Bethesda, MD: American Fisheries 

Society, Symposium. 70: 1127–1142.

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1999. Multiscale thermal refugia and stream habitat 

associations of chinook salmon in northeastern Oregon. 

Ecological Applications. 9: 301–319.

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FS]. 1990. Land and resource management plan for 

Olympic National Forest. Washington, DC: U.S. 

Government Printing Office. 370 p. 
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U.S. Department of Agriculture, Forest Service; 

U.S. Department of the Interior, Bureau of Land 

Management [USDA and USDI]. 1994. Record of 

decision for amendments to Forest Service and Bureau 

of Land Management planning documents within the 

range of the northern spotted owl [Place of publication 

unknown]. 74 p. [plus attachment A: standards and 

guidelines]. 

U.S. Fish and Wildlife Service [USFWS]. 2004. Draft 

recovery plan for the coastal-Puget Sound distinct 

population segment of bull trout (Salvelinus confluentus). 

Volume II (of II): Olympic Peninsula Management Unit. 

Portland, OR. 277 + xvi p.

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history of pacific salmon in dynamic environments. 

Evolutionary Applications. 1: 189–206.
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Chapter 6: Climate Change and Vegetation Management 

at Olympic National Forest and Olympic National Park

Jessica E. Halofsky, David L. Peterson, Carol Aubry, Christopher Dowling, and Steven A. Acker1

1 Jessica E. Halofsky is a research ecologist, University of Washington, College of the Environment, School of Forest Resources, 

Box 352100, Seattle, WA 98195-2100; David L. Peterson is a research biological scientist, U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Research Station, Pacific Wildland Fire Sciences Laboratory, 400 N 34th St., Suite 201, Seattle, WA 98103; 

Carol Aubry is a forest geneticist, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 Black Lake Blvd. 

SW, Olympia, WA 98512-5623; Christopher Dowling is the supervisory forester, timber and vegetation program manager and forest 

silviculturist, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 

98512-5623; Steven A. Acker is the supervisory botanist, Olympic National Park, 600 E. Park Ave., Port Angeles, WA 98362.

Vegetation on the Olympic Peninsula

The Olympic Peninsula has steep and dissected topography, 

which results in temperature and precipitation gradients and 

varied climatic environments (Peterson et al. 1997). The 

western, coastal side of the peninsula is characterized by a 

wet and humid maritime climate. Higher elevations on the 

western side of the peninsula receive as much as 5 m of precipitation per year (Henderson et al. 1989). The northeastern 

portion of the peninsula, in contrast, is characterized by a 

drier, more continental climate owing to the rain-shadow 

effect of the Olympic Mountains (and prevailing winds from 

the southwest during the winter), and rainfall in this area 

is as low as 0.5 m per year at lower elevations (Henderson 

et al. 1989). Most precipitation falls between October and 

March, resulting in low summer soil moisture, particularly 

in the northeastern portion of the peninsula. 

Dominant forest species differ with climatic conditions 

found on the peninsula (Buckingham et al. 1995) (fig. 6.1). 

Lower elevation forests on the western side of the peninsula 

are dominated by Sitka spruce, with western hemlock and 

western redcedar as common associates (Sitka spruce zone 

in fig. 6.1) (See a "Common and Scientific Names"). Red 

alder and bigleaf maple are also abundant in some locations. At lower to middle elevations, western hemlock and 

Douglas-fir are the dominant overstory species (western 

hemlock zone in fig. 6.1). Pacific silver fir dominates mid to 

upper slope forests, except in very dry locations, sometimes 

sharing dominance with Douglas-fir and western hemlock 

(Pacific silver fir zone in fig. 6.1). Mountain hemlock is 

dominant at higher elevations (mountain hemlock zone in 

fig. 6.1) in all but the driest locations, where subalpine fir is 

dominant (subalpine fir zone in fig. 6.1) (Henderson et al. 

1989). 

In the northeastern portion of the peninsula, distributions with elevation differ. Lower elevation forests are 

dominated by western hemlock and Douglas-fir (western 

hemlock zone in fig. 6.1). Grand fir, western redcedar, and 

Pacific silver fir share dominance with Douglas-fir and 

western hemlock at many mid-elevation sites on the east 

side of the peninsula (western hemlock and Pacific silver 

fir zones in fig. 6.1), but Douglas-fir is dominant on southfacing slopes in dry areas (Douglas-fir zone in fig. 6.1). 

Subalpine fir is a major overstory species at higher elevations, with lodgepole pine dominant in some areas (subalpine fir zone in fig. 6.1). Mountain hemlock and subalpine 

fir give way to subalpine meadows at the highest elevations 

(parkland mountain hemlock zone in fig. 6.1). 

Potential Climate Change Effects on 

Vegetation on the Olympic Peninsula

Climate, in concert with landscape and local-scale variables, dictates vegetation distribution across landscapes by 

placing both thermal and water constraints on plant regeneration, establishment, and growth. Past species response 

to changing climate observed in the paleoecological (pollen 

and fossil) record shows that the abundance and distribution of plant species shift individualistically in response to 

climate fluctuations (Davis and Shaw 2001, Delcourt and 

Delcourt 1991, Whitlock 1992); different species respond 

in varied ways to changing climate, leading to new species 

assemblages and communities. Increasing temperatures 

associated with climate change, and corresponding 

increases in summer drought stress and fire frequency in 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 6.1—Vegetation zones (based on climate zones and potential climax or dominant species within climate zones) on the 

Olympic Peninsula. 

the Pacific Northwest, will probably lead to changing 

species distribution in the region, resulting in forest types 

different from those we see today (Zolbrod and Peterson 

1999). There are several information sources useful for 

predicting potential climate change impacts on vegetation 

and future forest composition and structure, including 

long-term paleoecological records, modern tree ring records 

of tree growth and establishment, current trends with recent 

warming, and model predictions for the future. The following section reviews these information sources for the 

Olympic Peninsula. 
63

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Paleoecological Records of Climate and Species 

Distribution

Paleoecological records from the Pacific Northwest and 

elsewhere show that during historical warm periods, many 

tree species moved poleward and upward in elevation. 

Poleward and upward shifts in elevation of species distributions involve changes in species abundance, rather than a 

species extirpation in areas where it was formerly dominant; shifting distributions represent leading edge dynamics 

rather than trailing edge contraction. For example, during 

a warmer period in the 19th century, western hemlock 

became dominant in areas where Pacific silver fir and 

mountain hemlock were dominant on Mount Rainier in the 

Washington Cascade Range (Dunwiddie 1986), suggesting 

that western hemlock will move up in elevation in a warmer 

climate (Zolbrod and Peterson 1999). Several studies have 

shown the range expansion of subalpine fir into alpine 

tundra at higher elevations in the northeastern portion of the 

Olympic Peninsula during historical warm periods (Brubaker and McLachlan 1996, Gavin et al. 2001, McLachlan 

and Brubaker 1995). The range expansion of subalpine 

fir around Moose Lake in the northeastern portion of the 

peninsula during a warm period around 11,000 BP was also 

associated with increased charcoal content in lake sediments, suggesting fire size and frequency increased near the 

lake (Gavin et al. 2001). 

During the warm and dry Holocene period circa 10,000 

to 6,000 BP, red alder, Douglas-fir, and lodgepole pine 

were abundant in forests of primarily western hemlock 

and spruce at lower elevations on the Olympic Peninsula 

(Henderson et al. 1989, Heusser 1977, Peterson et al. 1997, 

Whitlock 1992). The abundance of these species in the 

Pacific Northwest has been associated with higher fire 

frequency (Cwynar 1987, Prichard et al. 2009). A study 

in the nearby north Cascade Range also found increased 

abundance of lodgepole pine, in association with high fire 

frequency, circa 10,500–8,000 BP (Prichard et al. 2009). 

In addition, western white pine became locally important 

in the Pacific Northwest during this period (Cwynar 1987), 

and Oregon white oak, a species usually associated with 

drier climates, was very common during this period in the 

northeastern Olympics (Petersen et al. 1983, Peterson et 

al. 1997). The range expansion of western redcedar, and 

further range expansion of western hemlock and Sitka 

spruce, occurred only after a period of lower temperatures 

and higher precipitation during the Holocene warm period, 

suggesting that the range of these species on the peninsula 

was limited by drought during that warm period (Whitlock 

1992). 

The paleoecological record from the Pacific Northwest 

shows that species with life history traits that allow survival 

during periods of frequent disturbance and in stressed 

environments have persisted during past periods of rapid 

climate change (Brubaker 1988, Whitlock 1992). For the 

Pacific Northwest, these species include red alder, Douglasfir, and lodgepole pine, suggesting that these species will be 

successful in a rapidly warming climate (Whitlock 1992). 

Other examples of species that have persisted over millions of years of climatic change on the Olympic Peninsula 

include Oregon white oak, giant chinquapin, bigleaf maple, 

and Pacific madrone (Henderson et al. 1989). 

Warmer and drier conditions at lower elevations on the 

Olympic Peninsula would likely result in expansion of the 

range of Douglas-fir and lodgepole pine. Other species that 

may expand their ranges under these conditions include 

western white pine, Oregon white oak, giant chinquapin, 

and Pacific madrone. Increased disturbance frequency may 

lead to the range expansion of red alder. The paleoecological record for the Pacific Northwest also suggests that many 

species, including western hemlock and subalpine fir, will 

become more abundant at higher elevations with warming 

on the peninsula. 

Modern Records of Climate, Tree Growth, 

and Fire

Before climate-induced changes in species distribution 

become apparent, changes in patterns of species establishment, growth, and mortality occur that eventually lead to 

broader range shifts (Littell et al. 2008). Dendroecological 

(tree ring) records from the past several hundred years 

allow observation of changes in growth of tree species with 

climate variation. Tree ring records show that individual 

tree growth and net primary productivity are sensitive 

to annual changes in climate in the Pacific Northwest 
64

GENERAL TECHNICAL REPORT PNW-GTR-844

(Brubaker 1980, Ettl and Peterson 1995, Graumlich et al. 

1989, Hessl and Peterson 2004, Holman and Peterson 2006, 

Littell et al. 2008, Nakawatase and Peterson 2006, Peterson 

and Peterson 2001). Effects of future climate change on both 

tree growth and establishment will differ by species (owing 

to varied physiologies and allocation patterns) and with 

elevation and topography (Ettl and Peterson 1995, Holman 

and Peterson 2006). 

At higher elevations on the Olympic Peninsula, tree 

growth and establishment are limited by snowpack amount 

and duration and associated growing-season length; greater 

snowpack amount and duration lead to a shorter growing 

season and decreased growth in high-elevation trees. For 

example, tree growth at the mid- and high-elevation subalpine fir-mountain hemlock and Pacific silver fir-western 

hemlock forests of the Hoh watershed on the western 

Olympic Peninsula is limited by snowpack and associated growing-season length (Holman and Peterson 2006, 

Nakawatase and Peterson 2006). Mountain hemlock growth 

in the Pacific Northwest is limited by spring snowpack 

depth and low summer temperatures (Peterson and Peterson 

2001). Similarly, subalpine fir at high-elevation, wetter sites 

on the Olympic Peninsula grows more slowly during years 

with lower summer temperature (Ettl and Peterson 1995), 

and regionally, growth of subalpine fir in the wetter portions 

of its range is negatively correlated with winter precipitation 

and spring snowpack depth (Peterson et al. 2002). Increasing temperatures with climate change will lead to more precipitation falling as rain rather than snow, earlier snowmelt, 

and thus lower snowpacks and longer growing seasons on 

the peninsula (Elsner et al. 2010). Longer growing seasons 

on the peninsula will alleviate growth-limiting factors and 

likely result in increased growth and productivity in highelevation forests. Longer growing seasons will likely also 

lead to higher tree establishment at higher elevations. 

In the dry northeastern Olympics, tree growth and 

establishment are limited by low summer soil moisture. 

For example, tree growth in the Dungeness watershed in 

the northeastern portion of the Olympic Peninsula has been 

shown to be limited by summer soil moisture, although less 

so at higher elevations (Nakawatase and Peterson 2006). 

Douglas-fir, although more drought tolerant than other 

major Olympic Peninsula tree species such as western 

hemlock, is limited by water supply at lower elevations in 

the Pacific Northwest (Littell et al. 2008). 

Increasing temperatures, lower winter snowpack, and 

early snowmelt with climate change will likely result in 

decreased soil moisture in parts of the Pacific Northwest, 

including many areas west of the Cascade Range in Washington state (Elsner et al. 2010). For the state of Washington, 

soil moisture content on July 1st is projected to decrease 

through the 21st century; for mean historical values (from 

the 1915 to 2006 period), July 1st soil moisture content is 

defined as 50 percent and is projected to be in the 38th to 

43rd percentile by the 2020s, 35th to 40th percentile by the 

2040s, and 32nd to 35th percentile by the 2080s (Elsner et 

al. 2010) (fig. 6.2). These decreases in summer soil moisture 

will likely lead to increased stress to tree species in some 

portions of the Pacific Northwest. 

Increased drought stress will likely result in decreased 

tree growth and forest productivity in the northeastern 

forests of the Olympic Peninsula. In the Sitka spruce forests 

on the west side of the peninsula, carbon dioxide fertilization could lead to increases in productivity (Norby et al. 

2005), if other factors, such as nutrient availability, do 

not limit growth. However, growth may also decrease in 

these Sitka spruce forests if summer soil moisture becomes 

sufficiently limiting with warming (Holman and Peterson 

2006, Nakawatase and Peterson 2006). 

Tree ring and modern fire records both show that years 

with widespread fire and fire extent are associated with 

warmer and drier spring and summer conditions in the 

Western United States (Heyerdahl et al. 2008, Littell et al. 

2009, McKenzie et al. 2004, Taylor et al. 2008, Westerling 

et al. 2006). Warmer spring and summer conditions in the 

Western United States lead to relatively early snowmelt, and 

lower summer soil and fuel moisture, and thus longer fire 

seasons (Westerling et al. 2006). Wildfire area burned in 

mountainous areas in the Western United States was positively related to low precipitation, drought, and high temperatures in the 20th century (Littell et al. 2009). Increased 

temperatures and drought occurrence in the Pacific Northwest from climate change will likely lead to increased fire 

frequency and extent. In addition, the intensity and severity 
65

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.2—Summary of projected July 1 soil moisture (volumetric soil water content) for the 2020s, 2040s, and 2080s (A1B 

and B1 Intergovernmental Panel on Climate Change emissions 

scenarios) as a percentile of simulated historical mean from 1916 

to 2006 (by using the Variabile Infiltration Capacity model). For 

future projections, percentiles less than 50 (browns) represent a 

decrease in soil moisture, and percentiles greater than 50 (blues) 

show an increase in soil moisture. Percentage change values represent spatially averaged July 1 soil moisture across Washington 

state. (Adapted from Elsner et al. 2010.)

of fires may increase in some areas if higher temperatures 

exacerbate low moisture content in fine fuels. 

Climate and fire on the Olympic Peninsula have been 

closely related in the past (Henderson et al. 1989). Warmer 

and drier periods of the past were likely characterized by 

increased fire frequency, particularly on the east side of 

the Olympic Peninsula (Gavin et al. 2001, Henderson et al. 

1989). Historical fires have been most frequent in the drier 

western hemlock, subalpine fir, and Douglas-fir vegetation 

types in the eastern half of the Olympic Peninsula (Henderson et al. 1989, Pickford et al. 1980). Henderson et al. 

(1989) calculated the average fire-return period for the last 

800 years in these vegetation types on the peninsula and 

found that the Douglas-fir zone had a fire-return period of 

138 years, the subalpine fir zone had a fire-return period of 

208 years, and the western hemlock zone had a fire-return 

period of 234 years. Decreases in fire-return intervals in 

these forest types would likely favor tree species that can 

survive fires or regenerate after fires, such as Douglas-fir 

and lodgepole pine, at the expense of less fire-tolerant 

species, such as western hemlock. Individual trees can withstand climatic variation, but disturbance events that result in 

mortality of mature trees could trigger changes in distribution and abundance of forest species on the peninsula. 

Trends With Recent Warming

Plant and animal species in different ecosystems across the 

world have begun to respond to recent warming over the 

last few decades (Parmesan 2006, Parmesan and Yohe 2003, 

Root et al. 2003). Most plant responses to recent warming 

have involved alteration of species’ phenologies, or timing 

of life history stages (Bradley et al. 1999, Menzel 2000, 

Menzel et al. 2001, Parmesan 2006). Advances in timing of 

flowering, for example, have been reported for plant species 

in Great Britain (Fitter and Fitter 2002), and evidence exists 

that the growing season has lengthened in the Northern 

Hemisphere in the last 50 years (Menzel and Fabian 1999, 

Parmesan 2006). Shifts in timing of flowering and the 

abundance of insect pollinators could lead to the decline of 

some plant species if pollinators are absent during times of 

peak flowering. 

Shifts in species’ distribution with warming in recent 

decades have been documented at several locations, 

including mountain ranges in western Europe (Grabherr 

et al. 1994, Lenoir et al. 2008) and southern California 

(Kelly and Goulden 2008). Consistent with paleoecological 

records, these shifts have generally involved movement 

upward in elevation or poleward (Parmesan 2006). Upward 

movement of tree lines has been documented in numerous 

mountainous locations across the world, including locations 

in Canada (Lescop-Sinclair and Payette 1995, Luckman 
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GENERAL TECHNICAL REPORT PNW-GTR-844

and Kavanagh 2000), Sweden (Kullman 2001), Bulgaria 

(Meshinev et al. 2000), Russia (Moiseev and Shiyatov 

2003), and New Zealand (Wardle and Coleman 1992). 

However, tree-line dynamics are complex and dependent 

on precipitation and microsite patterns in addition to 

temperature (Malanson et al. 2007, Parmesan 2006). A 

meta-analysis of response of tree lines at 166 sites (from 

around the world, but mostly in North America and Europe) 

to recent warming found that tree lines at sites with more 

winter warming were more likely to have advanced than 

tree lines at sites with less warming. In addition, tree lines 

with a diffuse form, characterized by decreasing tree 

density with increasing altitude or latitude, were more likely 

to have advanced than those with an abrupt form, characterized by a continuous canopy with no decline in density right 

up to tree line (Harsch et al. 2009). It is possible that diffuse 

tree lines are more responsive to warming because tree 

growth, but not survival, is limited by climatic factors. In 

contrast, winter stress factors that cause plant damage and 

limit survival may have a stronger influence on abrupt tree 

lines (Harsch et al. 2009). 

The frequency of some drought-related disturbance 

events has increased with recent warming. Tree mortality events in the Southwestern United States have been 

attributed to late 20th-century warming and related drought 

(Breshears et al. 2005, 2009). Increased temperatures have 

led to drier fuel levels, longer fire seasons, and an increase 

in years with widespread fire across the Western United 

States (Littell et al. 2010, Westerling et al. 2006). 

Insect outbreaks, such as that of the mountain pine 

beetle, have been recorded across a broad spectrum of latitude and temperature regimes in the past in western North 

America. However, the severity and distribution of some 

recent outbreaks differ from what can be inferred from 

historical records, and higher temperature associated with 

climate change is believed to be a significant factor in these 

differences (Aukema et al. 2008, Carroll et al. 2004, Logan 

and Powell 2001). For example, the expansive mountain 

pine beetle outbreak in British Columbia has expanded into 

northern areas and into areas east of the Rocky Mountains 

in Alberta, where mountain pine beetles were not successful 

in the past because of cold winter temperatures (Carroll 

et al. 2004). Current conditions on the Olympic Peninsula 

do not preclude mountain pine beetles from infesting and 

killing hosts, and the suitability for mountain pine beetle 

outbreaks at higher elevations in the Olympics is expected 

to increase under moderate warming (Littell et al. 2010). 

Besides the effects of changing climate on insect reproductive cycles, timing and severity of outbreaks will depend 

on availability of susceptible ages and sizes of lodgepole 

pine, western white pine, and whitebark pine and the stand 

conditions within which they reside. 

The exotic balsam woolly adelgid can infest both 

Pacific silver fir and subalpine fir on the Olympic Peninsula. 

This insect generally does not kill trees quickly, but will 

result in the slow demise of infested trees. Mitchell and 

Buffam (2001) observed that 3 to 4 years of warmer than 

average summers resulted in increased adelgid damage in 

subalpine fir at higher elevations in Oregon and Washington. 

They stated that, “If there was a permanent or long-term 

(decades) increase in summer temperatures, it is likely we 

would see an expanded range for the balsam woolly adelgid 

within the subalpine fir ecotypes—upward in elevation 

and to other new environments.” This suggests that, with 

warmer temperatures, balsam woolly adelgid will have 

greater effect on subalpine fir than is now being experienced 

on the Olympic Peninsula.

Besides the increased fire risk in drought-stressed 

forests, increased moisture stress may leave forests in the 

Western United States more susceptible to insect attack 

(Allen and Breshears 1998, Breshears et al. 2005, Hicke et 

al. 2006, Shaw et al. 2005). As temperature increases, any 

increase in moisture stress will increase the susceptibility of 

Douglas-fir on the peninsula to attack by Douglas-fir beetle. 

On the Olympic Peninsula, Douglas-fir beetle outbreaks 

are generated by wind events, which result in significant 

amounts of blowdown. Beetle populations build up in the 

downed trees, and then can attack and kill standing green 

Douglas-firs. These outbreaks will subside within 3 years 

if no subsequent blowdowns occur, and the numbers of 

standing trees that are killed will depend on the relative 

moisture stress of these trees. Historically, after blowdowns, 

mortality has been higher in the drier, eastern habitats of 

the peninsula than in the wetter, western habitats. Any 
67

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Box 6.1—Model types that assess potential effects of climate change on vegetation. Adapted from 

Robinson et al. (2008) 

Gap models

• Gap models simulate forest interactions and dynamics 

on a small, gap-sized patch of land (usually 0.01 ha 

and larger). 

• The geographic extent of analysis ranges from forest 

stands to regions.

• Ingrowth, growth, and death of individuals of one or 

more species on the patch are simulated over time.

• Dynamics in gap models are based on species-specific 

parameters, competition (e.g., relative height), light, 

temperature, and soil moisture. 

• Output includes density, basal area, biomass, and 

leaf area index by species and by stand. Information 

on each live tree is also available (e.g., species and 

diameter).

• Gap models use monthly temperature and precipitation, and so can respond to novel climate. 

• Some gap models have recently been adapted to be 

sensitive to changes in soil moisture and carbon 

dioxide concentrations.

Climate envelope models

• Climate envelope models (CEMs) are statistical models 

that predict future species distribution based on the 

relationship between current species distribution and 

climate variables (and sometimes other variables).

• CEMs use basic climate information as input.

• The geographic extent of analysis is variable, but 

regional analyses are typical. Modeling unit differs 

with input information.

• CEMs represent a snapshot in time and do not show 

variability in species distribution over time.

• These models assume that climate is the primary 

determinant of a species distribution and that the 

current relationship between a species and climate 

will hold under changing climate. 

• CEMs do not account for competition, dispersal, or 

evolutionary change in vegetation communities. 

• CEMs do not account for increases in carbon dioxide 

(CO2) and changes in disturbance regimes.

Dynamic global vegetation models

• Dynamic global vegetation models (DGVMs) simulate 

key physiological processes in plant communities to 

infer vegetation type over time.

• DGVMs use soil and climatic information (hourly to 

yearly). 

• DGVMs can respond to novel climate and are sensitive 

to changes in CO2 and fire regimes. 

• The geographic extent of analysis ranges from landscape to global, with modeling unit ranging from a 

30 m2 to several-square kilometer pixel.

• Output shows distribution of broad vegetation functional types over time but not individual species.

• DGVMs can identify limiting factors in different 

regions.

• DGVMs do not consider complex topography, land 

use change, management, pests, or herbivores.

changes in moisture regimes would affect the distribution 

of Douglas-fir beetle-caused mortality from a wind event 

on the peninsula. Recently burned forests may also lead to 

increases in Douglas-fir beetle populations, and subsequent 

mortalilty of additional green trees. In turn, these insect 

outbreaks can alter fuel and forest stand conditions which, 

at certain points after infestation, could result in increased 

risk of high-severity fire (Jenkins et al. 2008). All of these 

disturbances may increase opportunities for establishment 

by exotic species (Joyce et al. 2008). In this way, disturbances could act synergistically to drive ecosystem change 

on the Olympic Peninsula (McKenzie et al. 2009).

Tree disease could also potentially increase with 

warming on the peninsula. The effects of climate change on 

host physiology, adaptation or maladaptation, and population genetics that affect host-pathogen interactions is uncertain (Kliejunas et al. 2009). However, based on existing 

knowledge of tree disease in western North America, it can 

be inferred that climate change will result in reductions in 

tree health and advantageous conditions for some pathogens 

(Kliejunas et al. 2009). Any drought stress that is realized 

owing to changing conditions will exacerbate the impacts of 

many pathogens (Kliejunas et al. 2009). 

Model Predictions for Future Vegetation Patterns 

With Climate Change

Along with past records, models can be used to project 

future ecosystem response to changing climate. Output 

from three different types of climate change impact 

models—gap, climate envelope, and mechanistic dynamic 
68

GENERAL TECHNICAL REPORT PNW-GTR-844

global vegetation models (box 6.1)—has been produced 

for the Olympic Peninsula. All of these model types have 

strengths and limitations but can be conceptually useful in 

assessing potential climate change effects on vegetation. 

Output from these different model types for the Olympic 

Peninsula is described below. 

Gap model results for the Olympic Peninsula—

A gap modeling study for the subalpine and upper montane 

zones of the Olympic Mountains under a warming climate 

(Zolbrod and Peterson 1999) suggested that in the wetter 

southwest areas, dominant tree species will shift upwards 

300 to 600 m; gap model study results predict that Pacific 

silver fir will increase in subalpine meadows and mountain 

hemlock forests and western hemlock will increase in 

Pacific silver fir forests. In the drier northeast, study results 

suggest that drought-tolerant species will become dominant 

at lower elevations. At higher elevations, subalpine fir will 

dominate north aspects, and lodgepole pine will dominate 

south aspects. In general, productivity will increase in the 

southwest owing to longer growing seasons (and lack of 

moisture limitations), and productivity will decrease in the 

northeast owing to increased evapotranspiration and lower 

soil moisture content during the summer. 

Climate envelope model results for the Olympic 

Peninsula—

Statistical ecological models, also known as climate 

envelope models, were developed for the state of Washington by Littell et al. (2010 with data from Rehfeldt et al. 

2006) to determine the potential for climate change to alter 

distribution of important tree species, including Douglas-fir, 

lodgepole pine, ponderosa pine, and whitebark pine. Under 

a moderate carbon dioxide-emission scenario (1 percent 

per year increase in greenhouse gases after 1990) (Rehfeldt 

et al. 2006), the envelope models suggested that there will 

be a significant decline in the area of suitable climate for 

Douglas-fir at lower elevations and in the southern portion 

of the Olympic Peninsula. A decrease in area of suitable 

climate for pine species, which could include whitebark 

pine and lodgepole pine, is also projected to occur at higher 

elevations on the Olympic Peninsula. 

As noted in box 6.1, several assumptions and limitations are associated with climate envelope models. First, 

climate envelope models assume that climate is the primary 

determinant of a species distribution and that the current 

relationship between a species and climate will hold under 

changing climate. In addition, these models do not account 

for several important determinants of plant species distribution, including competition, dispersal, evolutionary change 

in vegetation communities, and changes in disturbance 

regimes. 

Dynamic global vegetation model results for the 

Olympic Peninsula—

The MC1 (Bachelet et al. 2001) dynamic global vegetation 

model (DGVM) is based on fundamental ecological processes and provides projections of future change in broad 

vegetation types with changing climate. Vegetation types 

in MC1 are based on life form (e.g., tree, shrub, or grass; 

evergreen or deciduous; broadleaf or needleleaf) and biome 

physiognomy (e.g., forest, savanna, or shrub-steppe) (see 

Neilson 1995). Species-level information is not included in 

MC1 output but can be inferred at coarse scales based on 

modeled vegetation type and local vegetation information. 

Additional limitations of MC1 are that it does not include 

complex topography, which may be important with changing climate in mountainous regions such as the Olympic 

Peninsula, or the effects of land use change, management, 

insects, or herbivores (see box 6.1). 

MC1 model projections are based on future climate projections from global climate models (GCMs). The Mapped 

Atmosphere-Plant-Soil System (MAPSS) Team (Forest 

Service, Pacific Northwest Research Station, Corvallis, 

Oregon) ran the MC1 model for the Pacific Northwest 

region, at a scale of 800 m, with inputs from three GCMs 

under three future carbon dioxide emissions scenarios. 

The three GCMs used in the analysis included the CSIROMK3.0 model from Australia (Dix et al. 2009, Gordon et al. 

2002), the Hadley CM3 model from the United Kingdom 

(Gordon et al. 2000, Pope et al. 2000), and the MIROC 3.2 

medium-resolution model from Japan (Hasumi and Emori 

2004). These three GCMs were chosen to bracket the range 

of scenarios available for the Western United States. In general, the Commonwealth Scientific and Industrial Research 
69

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.3—Projected modal vegetation types on the Olympic Peninsula for the 2010–20 period 

compared to modeled historical vegetation types. Projections are from the MC1 model for three 

global climate models (GCMs) (rows) and two Intergovernmental Panel on Climate Change 

(IPCC) carbon dioxide emissions scenarios (columns). The Commonwealth Scientific and Industrial Research Organization’s (CSIRO) GCM projects a relatively cool and wet Pacific Northwest, whereas the Model for Interdisciplinary Research on Climate (MIROC) projects a hot and 

wet Pacific Northwest, and the Hadley model projects a hot and dry Pacific Northwest. The B1 

emissions scenario is characterized by relatively low future emissions, and the A2 scenario is 

characterized by relatively high future emissions. Olympic National Park and Olympic National 

Forest are outlined in black. (Data from R. Neilson and the MAPSS Team, USDA Forest Service 

and Oregon State University, Corvallis, Oregon.)

Organization (CSIRO) model 

projections show a relatively cool 

and wet Pacific Northwest, whereas 

the Model for Interdisciplinary 

Research on Climate (MIROC) 

model projections show a hot and 

wet Pacific Northwest, and the 

Hadley projections show a hot and 

dry Pacific Northwest. The carbon 

dioxide emissions scenarios used in 

the analysis included the Intergovernmental Panel on Climate 

Change (IPCC) special report on 

emissions scenarios (Nakićenović 

and Swart 2000) B1 (relatively low 

future carbon dioxide emissions), 

A1B (moderate future carbon 

dioxide emissions), and A2 (relatively high future carbon dioxide 

emissions) scenarios. 

Here we present MC1 output 

on vegetation shifts and fire 

dynamics on the Olympic Peninsula through the end of the century 

for the three GCMs described 

above and the B1 and A2 emissions 

scenarios (relatively low and high 

emissions scenarios, respectively) 

(figs. 6.3 through 6.8). The MC1 

output is based on model runs that 

included a relatively high carbon 

dioxide fertilization effect (Norby 

et al. 2005) and potential nitrogen 

limitation. Changes in vegetation 

type in figures 6.3 through 6.5 

indicate that the climate will no 

longer be suitable for the former 

vegetation type and that changes in 

species composition and abundance 

are likely. However, changes in 

species composition and abundance 

will likely be gradual because of 
70

GENERAL TECHNICAL REPORT PNW-GTR-844

Table 6.1—Dominant and associated species for current vegetation (elevation/moisture) zones on the Olympic 

Peninsula with potential dominant species in 2100a b

Current

vegetation Current dominant Potential dominant

zones species Current associates species in 2100

Sitka spruce Sitka spruce (-), Douglas-fir (+), red alder (+), Douglas-fir, western redcedar, 

 western hemlock (-), Pacific silver fir (+), bigleaf red alder

 western redcedar (+) maple (+)

Western Western hemlock (-), Western redcedar (-), lodgepole pine (+), Douglas-fir, lodgepole pine,

 hemlock Douglas-fir (+) western white pine (+), grand fir (-), western white pine

 bigleaf maple (-)

Douglas-fir Douglas-fir (+), Western hemlock (-), western redcedar Douglas-fir, lodgepole pine, 

 lodgepole pine (+) (-), madrone (+), western white western white pine

 pine (+), Rocky Mountain juniper (+), 

 golden chinquapin (+)

Pacific Pacific silver fir (-), Alaska yellowcedar (-), western Western hemlock, western

 silver fir western hemlock (+) redcedar (+), Douglas-fir (+), redcedar, Douglas-fir, western

 mountain hemlock (-), western white white pine

 pine (+)

Mountain Mountain hemlock (-), Subalpine fir (+), Alaska yellowcedar (+), Pacific silver fir, western

 hemlock Pacific silver fir (+) western white pine (+), western hemlock hemlock, western white pine

 (+), Douglas-fir (+)

Subalpine fir Subalpine fir (-), Whitebark pine (-), Alaska yellowcedar (-), Lodgepole pine, Douglas-fir

 lodgepole pine (+) Pacific silver fir (-), Douglas-fir (+), 

 western hemlock (+)

Alpine — — Subalpine fir, mountain hemlock, 

 Alaska yellowcedar, whitebark

 pine

— = no tree species present.

a Potential dominant species were determined assuming that the next century will be hotter, with increasing summer drought stress, and that disturbance 

frequency (either fire on the east side of the peninsula or windstorms on the west side of the peninsula) will increase over the next century to facilitate 

species transition. It was also assumed that species dispersal would not be a limiting factor for movement in response to changing climate. Expected 

increases or decreases in abundance of current dominant and associate species are indicated with a (+) or (-), respectively. 

b Henderson, J.A.et al (1989). 

the high tolerance of mature trees to climatic variation; 

disturbances such as fire will likely be the main triggers for 

major compositional change. To interpret the MC1 output 

for the Olympic Peninsula, we focused on coarse-scale 

changes in vegetation type and disturbance, and the factors 

that led to those changes, and related them to likely changes 

in species composition and abundance (table 6.1). 

In many of the future scenarios in MC1, there is a 

decline in the extent of the high-elevation tundra and 

subalpine vegetation types on the Olympic Peninsula by 

2040–2060 (fig. 6.4), and there is also an almost complete 

loss of the tundra and subalpine vegetation types under 

most scenarios by 2070–2099 (fig. 6.5). This suggests that 

suitable conditions for tundra and subalpine vegetation will 

decline substantially or disappear by the end of the 21st

century with warming on the peninsula. Large-scale 

dispersal of plant species to the Olympic Peninsula will 

likely be limited because of isolation from mainland areas 

by water and lower elevation zones (Peterson et al. 1997, 

Zolbrod and Peterson 1999). Thus, changes in distribution 

and abundance of plant species must occur within the 

existing populations and communities on the peninsula, 

and species adjustments to changing climate are expected 

to be mainly altitudinal or between aspects (Zolbrod and 
71

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.4—Projected modal vegetation types on the Olympic Peninsula for the 2040–60 

period compared to modeled historical vegetation types. Projections are from the MC1 model 

for three global climate models (GCMs) (rows) and two Intergovernmental Panel on Climate 

Change IPCC carbon dioxide emissions scenarios (columns). The Commonwealth Scientific 

and Industrial Research Organization’s (CSIRO) GCM projects a relatively cool and wet Pacific 

Northwest, whereas the Model for Interdisciplinary Research on Climate (MIROC) projects a 

hot and wet Pacific Northwest, and the Hadley model projects a hot and dry Pacific Northwest. 

The B1 emissions scenario is characterized by relatively low future emissions, whereas the 

A2 scenario is characterized by relatively high future emissions. Olympic National Park and 

Olympic National Forest are outlined in black. (Data from R. Neilson and the MAPSS Team, 

USDA Forest Service and Oregon State University, Corvallis, Oregon.) 

Peterson 1999). In the former range 

of tundra and subalpine vegetation 

types, other species will likely 

become dominant, including tree 

species from lower elevations (see 

subalpine fir and alpine vegetation 

types in table 6.1). 

Under the CSIRO GCM A2 

scenario (cool and wet Pacific 

Northwest), there is a range expansion of the temperate warm mixedvegetation type in the northwestern 

portion of the peninsula in the 

2040–60 period (fig. 6.4). This 

vegetation change is in response to 

increased precipitation (specifically 

in the summer compared to the rest 

of the year), which allows for range 

expansion of deciduous broadleaf 

species. In the northwestern portion 

of the peninsula, this could include 

species such as vine maple, bigleaf 

maple, and red alder. However, by 

the end of the century, the maritime 

evergreen needleleaf forest again 

becomes more dominant than the 

temperate warm mixed-vegetation 

type (fig. 6.5). This is because 

precipitation increases under the 

CSIRO A2 scenario toward the end 

of the century, but the summers are 

not as wet relative to the rest of the 

year as they were in mid century. 

Evergreen needleleaf species are 

likely to maintain dominance under 

those conditions (Neilson 1995). 

Although the CSIRO scenarios 

are generally characterized by 

a relatively cool and wet Pacific 

Northwest, the distinct seasonality in rainfall and lower summer 

precipitation levels under the 
72

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 6.5—Projected modal vegetation types on the Olympic Peninsula for the 2070–99 

period compared to modeled historical vegetation types. Projections are from the MC1 model 

for three global climate models (GCMs) (rows) and two Intergovernmenata Panel on Climate 

Change (IPCC) carbon dioxide emissions scenarios (columns). The Commonwealth Scientific 

and Industrial Research Organisation’s (CSIRO) GCM projects a relatively cool and wet Pacific 

Northwest, whereas the Model for Interdisciplinary Research on Climate (MIROC) projects a 

hot and wet Pacific Northwest, and the Hadley model projects a hot and dry Pacific Northwest. 

The B1 emissions scenario is characterized by relatively low future emissions, and the A2 

scenario is characterized by relatively high future emissions. Olympic National Park and 

Olympic National Forest are outlined in black. (Data from R. Neilson and the MAPSS Team, 

USDA Forest Service and Oregon State University, Corvallis, Oregon.) 

CSIRO scenarios lead to increased 

fire activity at lower elevations on 

the eastern side of the peninsula 

by the end of the century (fig. 

6.8). Fire-tolerant species, such as 

Douglas-fir and lodgepole pine, 

will likely expand their ranges on 

the east side of the peninsula with 

increased fire. 

With the MIROC GCM (hot 

and wet Pacific Northwest) as input 

to MC1, there is a range expansion 

of the temperate warm mixed-forest 

and subtropical mixed forest vegetation types by the end of the 21st

century, mainly on the west side of 

the Olympic Peninsula (fig. 6.5). 

The range expansion of these temperate and subtropical forest types 

is at the expense of the currently 

dominant maritime evergreen 

needleleaf forest. This shift to 

temperate and subtropical vegetation types is a response to increases 

in average monthly temperatures 

and a decrease in winter frosts. 

Higher summer temperatures may 

eventually lead to drought stress in 

forest types that are not currently 

stressed in the summer months, 

mainly Sitka spruce forests, leading 

to shifts in dominance to more 

drought-tolerant species, such as 

western redcedar (table 6.1).

Under the hot and dry scenario 

with the Hadley model, MC1 shows 

a range expansion of the temperate 

evergreen needleleaf forest on the 

east side of the Olympic Peninsula 

by mid 21st century, with even 

greater expansion by the end of 

the century (figs. 6.4 and 6.5). This 
73

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.6—Projected average annual fraction of cell burned on the Olympic Peninsula for the 

2010–20 period compared to modeled historical fire activity. This output is derived by averaging the area of a cell that is burned over the period of interest. Number are not shown in the 

legend because they are not intuitive. However, darker colors indicate more fire. Projections are 

from the MC1 model for three global climate models (rows) and two Intergovernnmental Panel 

on Climate Change carbon dioxide emissions scenarios (columns). The B1 emissions scenario 

is characterized by relatively low future emissions, and the A2 scenario is characterized by 

relatively high future emissions. CSIRO = Commonwealth Scientific and Industrial Research 

Organization; MIROC = Model for Interdisciplinary Research on Climate. Olympic National 

Park and Olympic National Forest are outlined in black. (Data from R. Neilson and the MAPSS 

Team, USDA Forest Service and Oregon State University, Corvallis, Oregon.) 

shift is driven by increased fire 

activity on the east side of the peninsula with increasing temperatures 

and summer drought under the hot 

and dry Hadley scenario (figs. 6.6 

through 6.8). In other locations in 

the Western United States, temperate evergreen needleleaf forests 

are characterized by regular fire 

occurrence and are dominated by 

pine species. The range expansion 

of this vegetation type on the east 

side of the peninsula suggests that 

fire- and drought-tolerant species, 

such as Douglas-fir, lodgepole 

pine, and western white pine, will 

become more abundant in east-side 

vegetation types, including the 

western hemlock and Douglas-fir 

types (table 6.1). 

Overall, MC1 output indicates 

that vegetation change is expected 

by mid century across GCM and 

emissions scenarios. More substantial vegetation changes are expected 

by the end of the century. Decline 

in the extent of alpine and subalpine vegetation types is expected 

across scenarios. Other changes 

in vegetation and fire activity 

differ by GCM and the associated 

future changes in temperature and 

precipitation. 

Vegetation Management 

at Olympic National 

Forest and Olympic 

National Park 

The following section provides 

information on vegetation management at Olympic National Forest 

(ONF) and Olympic National Park 
74

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 6.7—Projected average annual fraction of cell burned on the Olympic Peninsula for 

the 2040–60 period compared to modeled historical fire activity. This output is derived by 

averaging the area of a cell that is burned in a year over the period of interest. Number are not 

shown in the legend because they are not intuitive. However, darker colors indicate more fire. 

Projections are from the MC1 model for three global climate models (rows) and two Intergovernmental Panel on Climate Change carbon dioxide emissions scenarios (columns). The B1 

emissions scenario is characterized by relatively low future emissions, and the A2 scenario 

is characterized by relatively high future emissions. Olympic National Park and Olympic 

National Forest are outlined in black. CSIRO = Commonwealth Scientific and Industrial 

Research Organization; MIROC = Model for Interdisciplinary Research on Climate. Olympic 

National Park and Olympic National Forest are outlined in black. (Data from R. Neilson and 

the MAPSS Team, USDA Forest Service and Oregon State University, Corvallis, Oregon.) 

(ONP), including (1) the context 

in which ONF and ONP manage vegetation, (2) guidance and 

constraints on vegetation management at ONF and ONP, and (3) 

the primary issues and activities 

relevant to vegetation management 

at ONF and ONP. This information, 

coupled with the likely effects of 

climate change on vegetation on 

the Olympic Peninsula (described 

previously), provide a basis on 

which to develop climate change 

adaptation options for vegetation 

management at ONF and ONP. 

Native Plants and 

Revegetation 

The ONF has instituted a native 

plant program that aims to maintain 

biodiversity and ecosystem health 

through the use of locally adapted, 

self-perpetuating populations 

of native plant species. Olympic 

National Forest uses both internal 

capacity and contractors to develop 

and maintain locally adapted 

sources of native plant seed and 

plant material to ensure these materials are available when needed for 

revegetation (fig. 6.9). Several grass 

seed production fields have been 

established. All propagule sources 

(seeds, cuttings, transplants) across 

the forest are mapped to help 

ensure that genetically appropriate 

native plant materials are used for 

site restoration. On-forest expertise 

has been developed to help in creating and implementing revegetation 

and restoration plans that maximize 

use of native plants.
75

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.8—Projected average annual fraction of cell burned on the Olympic Peninsula for 

the 2070–99 time period compared to modeled historical fire activity. This output is derived 

by averaging the area of a cell that is burned over the period of interest. Number are not 

shown in the legend because they are not intuitive. However, darker colors indicate more fire. 

Projections are from the MC1 model for three global climate models (GCMs) (rows) and two 

Intergovernmental Panel on Climate Change carbon dioxide emissions scenarios (columns). 

The B1 emissions scenario is characterized by relatively low future emissions, and the A2 

scenario is characterized by relatively high future emissions. Olympic National Park and 

Olympic National Forest are outlined in black. CSIRO = Commonwealth Scientific and Industrial Research Organization; MIROC = Model for Interdisciplinary Research on Climate. (Data 

from R. Neilson and the MAPSS Team, USDA Forest Service and Oregon State University, 

Corvallis, Oregon.) 

Olympic National Park 

conducts revegetation activities 

in a variety of locations. Staff 

specialists conduct regular inventory and monitoring in wilderness 

areas, particularly along trails and 

at campsites, to determine if areas 

require revegetation. Park teams 

carefully select, plan, execute, 

and monitor success of restoration 

projects. Projects involve obtaining 

plant material, staging, site preparation, planting, mulching, and site 

protection/facilities improvement. 

Most restoration projects require 

plant seeds, cuttings, or transplants 

produced from native plant materials collected in the immediate 

vicinity. 

Exotic Species Management

Exotic plants have become established in many locations at ONF. 

Some exotic species are considered 

invasive because their introduction 

causes or is likely to cause economic or environmental harm, and 

control efforts are focused on these 

invasive species. Invasive species 

infestations are primarily located in 

disturbed areas along road systems, 

in timber sale units, at administrative sites, in high public use areas 

(e.g., parking areas, viewpoints), in 

previously disturbed areas such as 

plantations, and in areas used for 

recreation such as campgrounds 

and dispersed recreation sites. 

Integrated manual, mechanical, 

herbicide, and restoration treatments 

are used at ONF to treat invasive 

plant infestations. Ongoing invasive 
76

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 6.9—Wet meadow plant community adjacent to a road 

scheduled for decommissioning on Olympic National Forest. Seed 

and cuttings of several species were collected from this site and 

used in the revegetation of the decommissioned roadbed. (Photo 

by Cheryl Bartlett, U.S. Forest Service, Olympic National Forest.) 

plant management efforts include prevention practices such 

as cleaning heavy equipment, using weed-free straw and 

mulch, using pelletized or certified weed-free animal feed, 

and restoring disturbed areas. Olympic National Forest is 

also involved in invasive species working groups to coordinate control efforts, including the Olympic Knotweed 

Working Group. 

Similar to ONF, exotic plants occur in many locations 

at ONP, and 190 known exotic plant species occur in the 

park (Buckingham et al. 1995). To combat this problem, 

the North Coast and Cascades Network of the National 

Park Service established an exotic plant management team 

(EPMT) in 2002. The EPMT and park natural resources 

staff work together to prevent introduction and control the 

spread of all exotic plants. Prevention involves working with 

park staff to increase knowledge; minimizing and repairing 

soil disturbance; preventing spread on equipment, tools, and 

boats; regulating wilderness stock use; working with park 

maintenance staff to ensure outside contractors use weedfree gravel sources; and collaborating with other agencies 

and neighbors. Exotic plant control methods include 

hand pulling, mowing, girdling, and targeted spraying of 

glyphosate and narrow-spectrum, low-toxicity herbicides. 

In addition, exotic plant monitoring is included in the North 

Coast and Cascades Network plan for long-term ecological 

monitoring.

Sensitive and Rare Plants

Olympic National Forest has 70 sensitive flora species, 

including 37 vascular plants, 17 fungi, 12 lichens, and 4 

bryophytes (mosses). The ONF runs a sensitive species 

program that includes biological evaluations of proposed 

actions on national forest lands to avoid and minimize negative impacts on the viability of sensitive species or a trend 

toward federal listings. The forest develops and implements 

conservation assessments and other tools for sensitive species, and develops and implements management practices to 

ensure that species do not become threatened or endangered 

because of Forest Service actions. 

The Olympic Peninsula has the highest concentration 

of rare plants in Washington, owing to the broad range 

of habitats and the geographic isolation of the peninsula. 

Rare plants at ONP include endemics or near-endemics, 

isolated populations, and species more common to the 

north (or east). Five of the seven peninsula endemics occur 

exclusively in subalpine and alpine zones, and the other two 

species occur from montane to alpine zones (Buckingham 

et al. 1995). Rare plant conservation actions at ONP include 

surveys of areas of proposed management or research 

activities, detailed surveys of distribution, and site-specific 

protection plans.

Prescribed Fire, Wildland Fire Use, and 

Hazardous Fuel Treatment

Olympic National Forest conducts slash pile burning for 

brush disposal and hazardous fuel reduction, and occasionally uses prescribed fire for restoration purposes. For 

example, in 2005, a prairie restoration burn was conducted 

in the Skokomish watershed. 

The Olympic National Park fire program is directed 

by a fire management plan, approved in 2005 (NPS 2003). 

Under the plan, prescribed burning is occasionally used, 

and fire managers may choose to monitor natural lightningignited fires to meet specific objectives. The park must complete a burn plan before any prescribed fire is permitted, 

and each planned fire must meet a specific set of conditions. 
77

Adapting to Climate Change at Olympic National Forest and Olympic National Park

2 Acker, S.A.; Woodward, A.; Boetsch, J.R. [et al.]. [N.d.] Forest vegetation monitoring protocol for the North Coast and 

Cascades network. [Natural Resource Report NPS/NCCN/NRR—no. TBD.] Manuscript in preparation. Fort Collins, CO: National 

Park Service. http://science.nature.nps.gov/im/units/nccn/Reports/Monitoring/NCCN_Monitoring_Plan_20050930.pdf. 

(12 March 2010). 

When fire cannot be used, hazardous fuel reduction is done 

by using manual removal or other means.

Vegetation Monitoring

Vegetation monitoring at ONF includes several different 

efforts. Botanists conduct rare plant monitoring in association with the University of Washington, Botanic Gardens 

Rare Plant Care and Conservation Program. Botanists 

intermittently monitor status of known populations of rare 

(to ONF) tree species. Silviculturists conduct informal 

ongoing silvicultural prescription effectiveness monitoring 

that includes monitoring of treatments such as understory 

precommercial thinning, commercial thinning, precommercial thinning with skips and gaps (skips are areas without 

tree harvest within a thinned stand; gaps are areas where all 

trees are harvested within a thinned stand), tree planting, 

and logging system effects on vegetation. Annual aerial 

surveys of insects and disease are also conducted regionally. 

Olympic National Park conducts forest monitoring as a 

part of the National Park Service North Coast and Cascades 

Network.2 The goal of this monitoring is to determine 

trends in tree mortality, recruitment, and growth in forests 

representing the range of environments in network parks. 

Attributes monitored include tree species, diameter, indicators of health, and factors contributing to death. Forest 

ecologists monitor three forest types (Sitka spruce, western 

hemlock-Douglas-fir, and subalpine fir) in the network 

in stands at least 80 years old. At this time, subalpine fir 

forests are monitored at Mount Rainier and North Cascades 

National Parks but not at ONP. 

Forest Thinning Program at Olympic National 

Forest

Timber harvest activities began on the Olympic Peninsula 

in the mid 1800s and at ONF in the 1920s. Until the 1990s, 

timber management generally consisted of clearcutting, 

broadcast burning, and tree replanting. Douglas-fir was 

the primary tree species chosen for artificial regeneration. 

These management practices resulted in the regeneration 

of over one-third of ONF into relatively young even-aged 

forests. These resulting plantations and managed forests 

were designed to maximize the production of wood products and are therefore densely stocked and structurally and 

compositionally simplified. The 1994 Northwest Forest Plan 

(NWFP) (USDA and USDI 1994) led to a movement toward 

management for ecological priorities, mainly the protection, 

enhancement, and acceleration of late-successional forest 

conditions. Timber production became a collateral opportunity rather than a primary objective. 

Olympic National Forest has instituted a multipleobjective commercial thinning program with the purpose of 

accelerating the process of late-successional forest development by creating conditions that encourage the growth of a 

diverse understory and multilayered stand structure. This 

thinning is conducted primarily in forest stands between 

40 and 80 years old that are designated as late-successional 

reserves (fig. 6.10); stands in this age range are the most 

economically viable stands to thin given the age limitations 

under the NWFP in late-successional reserve management. However, thinning in adaptive management areas 

is concentrated in stands 40 to 120 years old (fig. 6.11). 

The thinning treatments at ONF are prioritized based on 

habitat improvement potential for the northern spotted owl, 

marbled murrelet, and Roosevelt elk; aquatic species needs; 

and economic considerations. Priority is generally given 

to young-growth forest located near old-growth forest to 

increase the area of contiguous late-successional habitat. 

To promote structural diversity, tree thinning prescriptions include variable-density thinning (thinning with skips 

and gaps) and provisions for snags and coarse woody debris 

for wildlife habitat. The skips (no thinning) are designed to 

function as small reserves distributed across the treatment 

area, providing a refuge for plant and animal species sensitive to disturbance. The variation in the landscape created 

by the gaps and the thinned areas are designed to provide 

for the habitat needs of other species. When adjusted for 
78

GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 6.10—Location and age of late-successional reserve (LSR) and adaptive management area (AMAs) stands on Olympic National Forest (ONF). Thinning, with the goals of increasing forest structural diversity and improving wildlife habitat, 

is one of the primary vegetation management activities on ONF. Thinning on ONF is conducted primarily in LSR forest 

stands between 40 and 80 years old, as stands in this age range are the most economically viable stands to thin, and thinning 

in LSRs more than 80 years in age is not permitted. Although thinning is not permitted in LSRs older than 80 years, thinning in AMAs is concentrated in stands greater than 40 but less than 120 years old. Thus, 40- to 80-year old LSR stands (in 

light green) and the 40- to 120-year old AMA stands (in orange) are the locations where ONF has the most opportunity for 

active management in adapting to climate change.

tree species, initial tree size, and crown class, variabledensity thinning generally increases average tree growth by 

about 25 percent (Roberts and Harrington 2008). Thinning 

in young stands is also often associated with improved 

tree health, vigor, long-term wind firmness, and possibly 

resilience to climate change. The redistributed sunlight, 

moisture, and nutrients can also further promote understory 

vegetative diversity and vigor (Thysell and Carey 2001). 

Precommercial thinning at ONF is conducted primarily 

in single-story stands that are 15 to 35 years old, depending 

on tree form, tree density, and stand accessibility. Some 

thinning has also been conducted on understory tree canopy 

layers in young stands, and skips have also been used. 
79

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 6.11—Thinning activities on Olympic National Forest. The 

forest has instituted a multiple-objective commercial thinning 

program with the purpose of accelerating late-successional forest 

development by creating conditions that encourage the growth of 

a diverse understory and complex multilayered stand structure. 

(Photo courtesy of USDA Forest Service, Olympic National 

Forest.) 

Figure 6.12—Whitebark pine seedlings tested for resistance to 

white pine blister rust at Dorena Genetic Resource Center. (Photo 

courtesy of USDA Forest Service, Olympic National Forest.) 

Figure 6.13—Whitebark pine cone collection as a part of the 

Olympic National Forest gene conservation program. (Photo 

courtesy of USDA Forest Service, Olympic National Forest.) 

This thinning enhances or maintains species diversity by 

reducing competition around ecologically important minor 

tree species and other vegetation that would normally be 

eliminated through suppression mortality by faster growing 

tree species. In addition, precommercial thinning is used to 

improve tree growth, vigor, form, and rate of development 

of late-successional forest characteristics.

Genetic Resources Program at Olympic National 

Forest

Olympic National Forest established a conifer orchard in 

1957 to maintain a seed bank of high-quality seed for use in 

reforestation and restoration. Orchard trees are grouped in 

blocks not only by species but also based on seed zones (by 

elevation, latitude, and longitude) so that collected seed is 

adapted to the areas in which it is planted. Douglas-fir, Sitka 

spruce, western hemlock, western white pine, and Pacific 

silver fir blocks are included. To plant trees resistant to the 

introduced disease white pine blister rust, western white 

pine and whitebark pine tree selections are tested through a 

regional disease resistance program (fig. 6.12). All the white 

pine seed harvested from the orchard has exhibited disease 

resistance, and the forest has developed a partnership with 

the Washington Department of Natural Resources, and the 
80

GENERAL TECHNICAL REPORT PNW-GTR-844

Quinault Indian Nation to share in orchard management 

and the seed crop. The forest also maintains an ex situ 

gene conservation seed collection of Douglas-fir, western 

white pine, and whitebark pine by individual tree (fig. 6.13). 

Seed storage by tree allows for maximum flexibility in the 

creation of custom seed lots for various future applications.

Adapting Vegetation Management to 

Climate Change at Olympic National 

Forest and Olympic National Park

Process Used to Develop Adaptation Strategies 

for Vegetation Management

To develop adaptation strategies for vegetation management 

on the Olympic Peninsula, the geneticist, silviculturists, and 

natural resources staff officer from ONF and forest ecologist and other natural resources staff from ONP engaged 

in a year-long exchange of ideas with scientists from the 

Forest Service Pacific Northwest Research Station (PNW), 

University of Washington (UW), and UW Climate Impacts 

Group (CIG). These exchanges involved discussion of 

potential impacts of climate change on vegetation on the 

Olympic Peninsula and discussion of various models that 

project potential impacts of climate change on vegetation. 

This exchange contributed to the development of vegetation 

management strategies described below. 

Participants identified limited experience with various 

models and model output as a challenge for managers in 

thinking about how to address potential effects of climate 

change, and as a result, ONF and ONP natural resources 

staff and UW and PNW scientists met to review various 

model types, model output, and the strengths and weaknesses of different models. A subsequent workshop focused 

on reviewing potential vegetation sensitivities to climate 

change and developing adaptation strategies and actions 

for vegetation management on the peninsula. Participants 

in the second workshop included regional scientists and 

natural resources staff from ONF and ONP. The workshop 

included a presentation from CIG scientist Jeremy Littell 

on climate projections for the state of Washington. Other 

presentations addressed the potential impacts of climate 

change on vegetation communities (J. Halofsky, UW) and 

on plant phenology and physiology (Connie Harrington, 

PNW), as well as current vegetation management at ONF 

(Carol Aubry) and ONP (Steven Acker). David L. Peterson 

(PNW) also gave a presentation on developing strategies 

for adaptation to climate change. The facilitated dialogue 

between scientists and managers that followed focused on 

development of adaptation options and action plans for 

vegetation management at ONF and ONP. The discussion 

was specifically focused on the following questions: (1) 

What are the principal vegetation sensitivities (e.g., tree 

growth, disturbance, geographic locations) on the Olympic 

Peninsula? (2) What are your priorities for adaptation? 

(3) Which approaches and techniques would you use to 

facilitate adaptation? and (4) How might the park and forest 

collaborate to adapt to climate change? Key points from the 

discussion are described in the section below and in table 

6.2. See box 6.2 for a general summary of projected climate 

change effects on vegetation on the Olympic Peninsula and 

related adaptation strategies for vegetation management at 

ONF and ONP. 

Key Vegetation Sensitivities With Climate Change 

on the Olympic Peninsula

Workshop participants identified several vegetation 

assemblages on the Olympic Peninsula, and the species 

that inhabit them, as being particularly sensitive to climate 

change. Establishment of trees and other woody species will 

likely increase with warming and decreased snowpack in 

subalpine and alpine meadows (Zolbrod and Peterson 1999). 

Tree encroachment and increased establishment of lower 

elevation species in alpine and subalpine plant communities 

may put some species that currently inhabit these locations 

at risk, especially rare and relict species. Warming temperatures and changes in hydrology with climate change could 

have significant impacts on moisture levels and species 

composition in wetlands on the peninsula, especially bogs 

and fens (Burkett and Kusler 2000). Increased drought 

stress and disturbance frequency may also put Sitka spruce 

rain forests at risk for compositional change (Holman and 

Peterson 2006, Nakawatase and Peterson 2006). 

Changing disturbance regimes with climate change 

will likely affect vegetation on the Olympic Peninsula. 

Storm intensity is projected to increase (Salathé et al. 2010), 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 6.2—Current and expected vegetation sensitivities to climate change on the Olympic Peninsula, and 

associated adaptation strategies and actions for vegetation management at Olympic National Forest (ONF) 

and Olympic National Park (ONP)a

Current and expected vegetation 

sensitivities to climate change Adaptation strategies and actions

Increased opportunity for exotic species • Continue to implement early detection/rapid response for exotic

 establishment species treatment (ONF). 

• Increase exotic species control efforts (ONP).

• Continue to exchange information on exotic species spread and 

control between ONF and ONP.

Potential for mortality events and regeneration • Develop a gene conservation plan for ex situ collections

 failures, particularly after large disturbances for long-term storage. 

• Identify areas important for in situ gene conservation.

• Maintain a tree seed inventory with high-quality seed for a range 

of species, particularly species that may do well in the future 

under hotter and drier conditions.

• Increase production of native plant materials for postflooding 

plantings.

Increased forest drought stress and decreased • Consider increasing the amount of thinning and possibly altering

 forest productivity at lower elevations thinning prescriptions to reduce forest drought stress (ONF).

• Use girdling, falling and leaving trees, prescribed burns, and 

wildland fire (ONP) to reduce stand densities and drought stress.

• Maximize early successional tree species diversity by retaining 

minor species during precommercial thinning activities to 

promote greater resilience to drier conditions.

• Consider including larger openings in thinning prescriptions and 

planting seedlings in the openings to create seed sources for 

native drought-tolerant species.

Altered ecosystem structure and potential • Prioritize actions that will help maintain ecosystem function.

 disruption of process and function • Focus on actions that will help minimize mass die-off and effects 

of major disturbances. 

• Create structures and processes that are viable over the long term.

All of the above • Conduct integrated and consistent inventory and monitoring of 

vegetation.

• Focus monitoring on sensitive locations such as wetlands and 

high elevations, on endemic or at-risk species, and on plant 

phenology. 

• Use feedback from monitoring in implementation of adaptive 

management.

a Sensitivities are based on projected climate change effects on Olympic Peninsula, including decreased summer soil moisture, changing patterns of 

vegetation establishment, growth and mortality, shifting species distributions, shifting phenology, increased fire frequency, increased winter flood 

frequency and magnitude, and potential for increased insect outbreaks.

potentially leading to increased frequency of landslides 

and windthrow. Fire frequency and extent are projected 

to increase on the peninsula (see MC1 model output figs. 

6.6–6.8). There is potential for more frequent and more 

severe disturbances owing to insects, including mountain 

pine beetle (Littell et al. 2010), and possibly Douglas-fir 
82

GENERAL TECHNICAL REPORT PNW-GTR-844

Box 6.2—Summary of projected climate change effects on vegetation on the Olympic Peninsula 

and related adaptation strategies for vegetation management at Olympic National Forest Olympic 

National Park

• Increased temperatures with climate change, and corresponding increases in summer drought stress and 

fire frequency in the Pacific Northwest, will lead to 

changing species distribution in the region, resulting 

in forest types different from those we see today.

• Increased temperatures with climate change will 

lead to longer growing seasons on the peninsula,

which will alleviate growth-limiting factors and 

likely result in increased growth and productivity in 

high-elevation forests.

• Increased drought stress with climate change will 

likely result in decreased tree growth and forest 

productivity in the northeastern forests of the 

Olympic Peninsula.

• Paleoecological (pollen and fossil) records from 

the Pacific Northwest and elsewhere show that during 

historically warm periods, many tree species moved 

poleward and upward in elevation, suggesting that on 

the Olympic Peninsula, species distributions will 

shift to higher elevations with warming.

• With warming on the Olympic Peninsula, warmer and 

drier conditions at lower elevations will likely result 

in expansion of the range of Douglas-fir and lodgepole pine. 

• Increased temperatures and drought occurrence with 

climate change will likely lead to increased fire frequency and extent on the Olympic Peninsula, particularly in the northeastern portion.

• Species phenology, or timing of life history events, is

also likely to shift in response to climate change on 

the peninsula.

• Olympic National Forest (ONF) and Olympic National 

Park (ONP) identified alpine and subalpine meadows, 

wetlands, and Sitka spruce rain forests as being 

particularly vulnerable to warming climate. 

• Both the forest and park affirmed the maintenance of 

functioning ecosystems in the face of climate change 

as a primary goal to continue to provide ecosystem 

services. Management actions that will help to maintain ecosystem function, such as restoration activities 

that create structures and processes that are viable 

over the long term, will be prioritized, when possible. 

• To conserve genetic resources, ONF will maintain a 

tree seed inventory with high-quality seed for a 

range of species, especially those that are adapted to 

a drier climate or greater variation in climate, and 

will develop a plant conservation framework for forest trees and habitats at risk under changing climate 

that includes a plan for ex situ seed collection.

• Both the forest and park will be prepared to treat 

increases in exotic plant species after disturbances 

by continuing to implement the early detection, rapid 

response program.

• The forest and park will work to conduct more 

integrated and consistent inventory and monitoring 

of vegetation.

• At ONF, increasing the amount and prioritization of 

thinning activities in forest stands could potentially 

increase resilience to climate change, because thinning can increase water availability and tree growth 

and vigor by reducing competition. 

• At ONP, prescribed fire and wildland fire in wilderness 

could be managed to reduce stand density and 

drought stress.

beetle, and balsam woolly adelgid (Mitchell and Buffam 

2001). Increases in these disturbances will increase opportunities for exotic species establishment (Joyce et al. 2008). 

Disturbances may also interact to drive ecosystem change 

(McKenzie et al. 2009).

Changes in plant phenology (Parmesan 2006), 

increased drought stress (Elsner et al. 2010, Littell et al. 

2010), and changing disturbance regimes (Littell et al. 2010) 

could lead to significant changes in plant regeneration patterns on the Olympic Peninsula. Workshop participants 

suggested that propagule production could be reduced 

owing to a warmer climate and associated stresses. In 

addition, site availability for seedling establishment may 

be limited under changing climate; an increase in tree 

mortality could result in increased cover of clonal species 

such as salal, which can limit opportunities for other species 

to become established. However, warming may lead to 

increased fire frequency (Littell et al. 2009, Westerling 

et al. 2006), which will likely increase opportunities for 

seedling establishment, including seedlings of species that 
83

Adapting to Climate Change at Olympic National Forest and Olympic National Park

were not dominant on a site before a fire event. Changes in 

regeneration patterns may lead to changing distribution and 

abundance of currently common species on the peninsula, 

leading to changes in ecosystem structure and function. 

Goals and Priorities for Adaptation in Vegetation 

Management

Both ONF and ONP affirmed the maintenance of functioning ecosystems in the face of climate change as a primary 

goal to continue to provide ecosystem services. Management actions that will help to maintain ecosystem function 

will be prioritized, when possible. Examples include actions 

to help minimize extensive tree mortality and effects of 

major disturbances, and restoration activities that create structures and processes that are viable over the long 

term. In addition, restoration planning will consider the 

functional role of species and habitats. For example, Sitka 

spruce may serve the same functional role as Douglas-fir in 

terms of stand structure (large trees or wood, or both) but 

not in terms of seed production and type of seed for wildlife 

(Peter and Harrington 2010). 

Biodiversity is the sum of species, ecosystem, and 

genetic diversity (Lovejoy and Hannah 2005). Maintenance 

of native plant biodiversity is an ongoing priority for ONF 

and ONP and includes such actions as protection, restoration, and monitoring of rare plant species or populations; 

planting a variety of species; and in situ and ex situ gene 

conservation. However, it is unclear which levels of biodiversity should be maintained in a changing climate. The 

definition of exotic species will also need to be reexamined 

periodically, and possibly modified, because of shifting 

species distribution with climate change. The definition 

of exotic species will likely influence how vegetation and 

biodiversity are managed with climate change. 

Adaptation Strategies and Actions for Vegetation 

Management at Olympic National Forest and 

Olympic National Park

Olympic National Forest will implement the following 

actions to maintain biodiversity and increase ecosystem 

resilience. These actions are likely to be effective under a 

variety of possible future scenarios.

• Maintain a tree seed inventory with high-quality 

seed for a range of species. One way to maintain seed 

inventory for tree species is to collect seed from the 

ONF conifer seed orchard, where seed is collected and 

stored by individual tree or by seed zone to maximize 

flexibility. 

• Working in partnership with ONP and other land 

managers, develop a plant conservation framework for 

forest trees and habitats at risk under changing climate, 

with an emphasis on nontree species associated with 

those habitats. An essential component of the framework will be a gene conservation plan for ex situ seed 

collections for long-term storage, including seed 

collections from rare species and encompassing the 

range of variation in widespread species. New areas 

that may become important for in situ gene conservation will be identified. Forest tree species will be 

evaluated for relative sensitivity to climate change, and 

tools and options, such as assisted migration, will be 

reviewed. A 5-year action plan will be the result of this 

effort.

• Continue to increase disease resistance in western 

white pine and whitebark pine. Both of these species 

are threatened by white pine blister rust, which has 

caused mortality and reduced vigor in susceptible 

conifer hosts in many parts of the Western United 

States (McDonald and Hoff 2001). 

• Increase the capacity to restore forest lands after large 

disturbances:

● Increase seed production and storage for native 

 tree species that are adapted to a drier or more 

 variable climate. Lodgepole pine, western white 

 pine, western redcedar, and Oregon white oak 

 are candidate species. 

● Be prepared to treat increases in exotic plant 

 species after disturbances by continuing to 

 implement the early detection/rapid response 

 program.

● Be prepared to seed/plant appropriate native 

 plant species after flooding by increasing the 

 ONF native plant materials program.
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GENERAL TECHNICAL REPORT PNW-GTR-844

Monitoring will be critical in detecting changes in 

phenology and plant species regeneration, growth, and 

mortality on the peninsula with changing climate (Joyce 

et al. 2008). Both ONF and ONP currently conduct vegetation inventory and monitoring, but the forest and park 

will conduct more integrated and consistent inventory and 

monitoring of vegetation. Monitoring can be focused on 

sensitivities identified through expert knowledge of Olympic Peninsula vegetation and climate-sensitive vegetation 

model projections (such as MC1 projections described 

previously). For example, monitoring could be focused on 

sensitive locations such as wetlands and high elevations, on 

endemic or at-risk species, and on plant phenology (both 

vegetative and reproductive events). Identifying species 

and ecosystems that are most susceptible to climate change 

through monitoring can inform prioritization of protection 

and restoration activities. 

Control of exotic species will maximize the resilience 

of native vegetation on the peninsula with changing climate 

(Joyce et al. 2009). The ONF will continue to implement 

their strategy of early detection/rapid response for exotic 

species treatment, and ONP will increase exotic species 

control efforts. Treatment of species that have the potential 

to delay development of desired forest structure will be prioritized. For example, treatment of Japanese knotweed may 

be prioritized because this species prevents establishment of 

conifers in riparian forests and thus has a negative effect on 

coarse wood input to streams and on stream habitat quality. 

The ONF and ONP could undertake an explicit process to 

identify desired future forest structure and composition in 

different locations. The forest and park will also continue to 

exchange information on exotic species spread and control. 

Thinning forest stands at ONF is another potential way 

to increase resilience to climate change, because thinning 

can increase water availability and tree growth and vigor by 

reducing competition (Roberts and Harrington 2008). The 

ONF currently has a forest thinning program focused on 

promoting late-successional forest conditions and improving wildlife habitat in young-growth stands, which could 

help to increase forest and wildlife resilience to climate 

change. Approximately 0.7 percent of the young-growth 

stands on the forest are treated annually, and increasing the 

amount of thinning could help to further increase resilience 

to climate change. However, funding for thinning at ONF is 

limited, and ONF has limited options on where thinning can 

occur owing to restrictions under the NWFP (fig. 6.10). 

In addition to considering an increase in amount of 

thinning, shifting the strategy in placement of thinning 

treatments could help to increase broad-scale resilience to 

climate change. Thinning treatments could be prioritized 

in locations where climate change effects, particularly 

increased summer drought, are expected to be most 

pronounced. Thinning for climate change resilience may 

also require changes in thinning prescriptions, primarily 

decreases in forest density and increases in gap size to 

provide for establishment and vigorous growing conditions 

for desired tree, shrub, and herbaceous species. 

Currently, many unthinned young-growth forests at 

ONF are characterized by high intertree competition, low 

tree and plant species diversity, low structural complexity, 

and declining structural stability (as compared to unmanaged old-growth forests) (Roberts and Harrington 2008). 

In young-growth forest stands under age 35, tree thinning 

could be used to reduce intertree competition that causes 

reductions in species diversity and suppression mortality 

and stress on trees. This thinning would be conducted to 

maximize tree growth and vigor by utilizing a uniform 

thinning with some skips to provide variation in understory 

growing conditions. This prescription could increase early 

successional tree species diversity by favoring retention of 

minor tree species regardless of their size. A wider range of 

tree species and more complex forest structure may provide 

resilience to a broader range of climatic conditions (Puettmann et al. 2009). 

If the severity of wind events increases with climate 

change, thinning activities can initially result in increased 

wind damage until the trees become adapted to the new 

environment (Roberts et al. 2007). However, over the long 

term, thinning of young growth can improve tree resistance 

to wind damage by decreasing tree height-to-diameter 

ratios (an indicator of the slenderness or taper of a tree bole) 

(Cremer et al. 1982). Uniformity of young-growth size and 

density, owing to their even age and high stocking, reduces 
85

Adapting to Climate Change at Olympic National Forest and Olympic National Park

the rate of crown differentiation, resulting in high heightto-diameter ratio development (Mitchell 2000, Roberts et 

al. 2007). Forests developing at these higher densities and 

located in wind-exposed areas may be too structurally 

unstable to survive disturbance to old age.

In young-growth forest stands over age 40, thinning 

could be used to increase structural stability, individual tree 

vigor, and variability in overstory and understory growing 

conditions to improve resilience of vegetation to climate 

change. An initial commercial thinning entry could be used 

to reduce intertree competition and maximize individual 

tree growth and vigor. A second commercial thinning entry 

could be implemented 10 to 20 years later and use variabletree spacing with skips and gaps. This would likely further 

release individual trees from competition and provide 

variability in growing conditions for understory vegetation 

to improve plant vigor and increase plant diversity (Carey 

and Wilson 2001).

To favor some of the tree species that may increase in 

abundance with climate change, such as relatively shadeintolerant western white pine, thinning prescriptions may 

include larger openings than those created in past thinnings. 

The ONF could also plant trees in openings to create seed 

sources for native species expected to increase in abundance 

with climate change. 

Other tools can also be used to improve vegetative 

growth and vigor by increasing water availability. Within 

wilderness areas of ONF and ONP, managers employ 

minimal active management to protect wilderness values 

and ecosystem processes. In this context, ONP will focus 

on managing wildland fire in wilderness to create gaps and 

reduce stand density. In addition, at both ONF and ONP, 

girdling and prescribed burns could be used to reduce stand 

density and thus drought stress. To improve wildlife habitat, 

girdled, thinned, and fire-killed trees can be left as structure 

rather than being removed. 

Key Questions and Future Directions

Climate change is one of many factors that must be considered by managers at ONF and ONP. Thus, projects will 

not be focused on climate change alone. However, expected 

effects of climate change can be incorporated into management strategies and the project planning process.

Climate change adaptation in vegetation management 

is essentially a long-term management experiment. Many of 

the proposed changes in vegetation management discussed 

above, such as the potential changes in thinning prescriptions, will provide opportunities to implement adaptive 

management, where feedback from monitoring provides 

direction for future management. It will be necessary for 

ONF and ONP to continue to support research, conduct 

monitoring, and develop tools to address effects of climate 

change. For example, a sensitivity rating for vegetation based on expected compositional changes could be 

developed to prioritize management actions. Identifying 

important triggers for life history events will also be critical 

in predicting likely vegetation change. These triggers will 

inform decisions in the future on such activities as assisted 

migration of plant species that are not currently found on 

the Olympic Peninsula. Until that time, ONF and ONP will 

work to increase ecosystem resilience and maintain ecosystem function by using the strategies and actions that have 

been outlined here. 

Acknowledgments

We thank Ron Neilson, Brendan Rogers, Dominique Bachelet, and Ray Drapek from the MAPSS team in Corvallis, 

Oregon, for use of MC1 output and help with mapping and 

interpretation of the output. We thank the scientists and 

managers that participated in the adaptation workshop, 

including Kurt Aluzas, Cheryl Bartlett, Tim Davis, Connie 

Harrington, Roger Hoffman, Chris Lauver, Jeremy Littell, 

Toni Lyn Morelli, Jeff Muehleck, Larry Nickey, Bob Obedzinski, Regina Rochefort, and Mark Senger. Dick Carlson 

and Mark Senger helped develop table 6.1. Paul Anderson, 

Connie Harrington, and Bruce Hostetler provided helpful 

reviews of this chapter. 

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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Chapter 7: Climate Change, Wildlife Management, and 

Habitat Management at Olympic National Forest and Olympic 

National Park

Jessica E. Halofsky, Susan Piper, Kurt Aluzas, Betsy Howell, Paul Griffin, Patti Happe, Kurt Jenkins, 

Catherine Hawkins Hoffman, Joshua Lawler, Michael Case, and Karen Reagan1

1 Jessica E. Halofsky is a research ecologist, University of Washington, College of the Environment, School of Forest Resources, 

Box 352100, Seattle, WA 98195-2100; Susan Piper is the wildlife, botany, and invasive plant program manager, and Betsy Howell

is a wildlife biologist, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; Kurt Aluzas is a wildlife biologist, U.S. Department of Agriculture, Forest Service, Olympic National Forest, 

295142 Hwy 101 South, Quilcene, WA 98376; Paul Griffin is a research wildlife biologist and Kurt Jenkins is a research wildlife 

biologist, U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Olympic Field Station, 600 East Park Ave., 

Port Angeles, WA 98362; Patti Happe is a wildlife biologist, Olympic National Park, 600 E. Park Ave., Port Angeles, WA 98362; 

U.S. Geological Survey, Forest and Rangeland Ecosystem Science Center, Olympic Field Station, 600 East Park Ave., Port Angeles, 

WA 98362; Catherine Hawkins Hoffman is the Climate Change Adaptation Coordinator, National Park Service Natural Resource 

Program Center, 1201 Oakridge Dr., Fort Collins, CO 80525 (formerly Chief, Natural Resources Division, Olympic National Park, 

Port Angeles, WA); Joshua Lawler is an associate professor of landscape ecology and conservation, University of Washington, 

College of the Environment, School of Forest Resources, Box 352100, Seattle, WA 98195-2100; Michael Case is a Ph. D. student, 

University of Washington, College of the Environment, School of Forest Resources, Box 352100, Seattle, WA 98195-2100; Karen 

Reagan is a Ph. D. student, University of Washington, Department of Biology, Box 351800, Seattle, WA 98195-1800.

Potential Climate Change Effects on 

Wildlife on the Olympic Peninsula

Although wildlife, or native animals, have some ability to 

cope with changing climate, human-caused climate change, 

in combination with other stressors to wildlife such as 

habitat loss and fragmentation, can greatly affect wildlife 

species and biodiversity (Hannah et al. 2005, Inkley et 

al. 2004). Similar to plant species, wildlife species will 

respond individualistically to climate change, with some 

species responding negatively and some positively. Species 

will respond to both direct and indirect effects of climate 

change. For example, increasing temperatures and changing 

precipitation will have direct physiological effects on some 

species. Other species will be affected mostly indirectly 

through climate-induced changes in phenology (timing of 

life history) relative to forage plants and invertebrate prey; 

shifts in geographic ranges and the density and ranges of 

competitor, forage, prey, and symbiotic species (and subsequent changes in biotic interactions); and effects from other 

stressors such as disturbance, insects, and disease. Related 

changes in habitat characteristics and quality will affect 

animal species viability. These effects will interact with 

existing stressors, leading to complex responses of wildlife 

populations to changing climate. 

Change is already evident in some wildlife species in 

response to warming over the last few decades. Changes in 

species physiology, distribution, and phenology are widely 

documented and directly attributed to recent warming 

(Parmesan 2006, Parmesan and Yohe 2003, Root et al. 

2003). These recent responses, along with past responses 

evident in the paleoecological record, and existing knowledge of species physiology and biogeography, can help 

in projecting how wildlife species will respond to future 

climate change. By using these lines of evidence, we discuss 

the potential direct and indirect effects of climate change on 

wildlife species and populations on the Olympic Peninsula 

and summarize potential climate change effects on Olympic 

Peninsula habitats. 

Direct Effects of Climate Change on Wildlife

Climate change will lead to warmer temperatures and 

likely drier summers on the Olympic Peninsula, and these 

changes will have direct physiological effects on some 

species. Many species on the peninsula rely on specific 

microhabitats or microclimates to maintain metabolic 

functions within physiological parameters. Structural 

habitat components that mediate microclimate include 

forest canopy that reduces evaporation and solar radiation; 

large decaying logs, hollow snags, and leaf litter; and alpine 
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GENERAL TECHNICAL REPORT PNW-GTR-844

environments in which slope, aspect, geologic attributes, 

and microtopography are controlling factors. Changes in 

the macroclimate or macrohabitat could either place more 

importance on these features or negate their ability to meet 

an animal’s needs. For example, species such as the American marten (See "Common and Scientific Names") rely on 

thermal cover provided by snow in subalpine and montane 

habitats during winter (Buskirk et al. 1989, Taylor and Buskirk 1994). Reduced snowpack on the Olympic Peninsula 

because of climate change (Elsner et al. 2010) could expose 

the marten and other species to lethally cold temperatures 

during winter. 

Bats also rely on specific microclimates in winter 

hibernacula. Hibernating bats require a cool, stable temperature in the winter to maintain a reduced metabolic rate 

(Brigham 1993, Fenton 1983, Fenton and Barclay 1980). 

Bats that either delay entering winter torpor because of 

higher ambient temperature or are aroused from torpor early 

because of unseasonably warm weather patterns could face 

energetic stress if insect prey is unavailable at those times 

(Humphries et al. 2002). 

Endothermic (warm-blooded) species, such as birds 

and mammals, may have to expend more energy to maintain 

constant temperature (homeostasis) with higher ambient 

temperatures in the summer months (Root and Hughes 

2005). Thus, higher temperatures may lead to changes in 

endothermic species’ microhabitat choices (e.g., increased 

retreat to shady habitats) during the summer. However, 

warmer winters and springs will likely result in less thermal 

stress on some species. Furthermore, changes in the spatial 

distribution of preferred habitat (with specific vegetation 

structure and species composition) will likely have a more 

direct effect on vertebrate species spatial distribution than 

on behavioral changes that are directly related to temperature.

Ectothermic (cold-blooded) species, such as reptiles, 

may benefit from increased temperatures on the peninsula 

because the peninsula has a relatively cool environment, 

and reptiles rely on the environment to warm themselves. 

Other ectothermic species, such as amphibians, rely on cool, 

moist microhabitat conditions to prevent overheating and 

desiccation. High temperatures can be lethal to amphibians, 

but amphibian species are generally adapted to a range of 

temperatures typical for their environment, making direct 

mortality from high temperatures rare (Carey and Alexander 2003). However, the amount and timing of precipitation 

can greatly affect the yearly reproductive output of an 

amphibian population (Carey and Alexander 2003). For 

example, because most amphibians lay eggs in standing 

water (Duellman and Trueb 1985), too little rainfall can 

result in egg and larval desiccation (Carey and Alexander 

2003). At the opposite extreme, too much precipitation at 

certain times during egg and larval development can lead to 

egg and larval mortality (Carey et al. 2005). Adult terrestrial amphibians are also susceptible to desiccation because 

of high rates of water loss from the skin and respiratory 

systems (Shoemaker et al. 1992). Survivorship may further 

decline during severe drought because low moisture levels 

can limit amphibian activity, mobility, ability to evade 

predators, and food supply (Carey and Alexander 2003). 

These examples illustrate that the extremes in temperature and precipitation, rather than the means, often have 

major effects on animal species. Because events such as 

drought and intense precipitation are expected to increase 

on the Olympic Peninsula, species will need to cope with 

increased frequency of extreme events. The Olympic torrent 

salamander (fig. 7.1), Cascades frog (fig. 7.2), and Van 

Dyke’s salamander are examples of species that may be 

directly affected by extremes in temperature and precipitation, and related changes in hydrology. 

Indirect Effects of Climate Change on Wildlife

Phenological shifts—

Warming temperatures with climate change will likely alter 

seasonal climate patterns. For example, on the Olympic 

Peninsula and in temperate ecosystems in general, climate 

change will likely result in earlier snowmelt, a shorter 

winter season, earlier onset of spring, and a longer growing 

season (Elsner et al. 2010, Menzel et al. 2003). Plant and 

animal life cycles are closely linked with changing seasons, 

and changes in seasonality with climate change will likely 

lead to altered phenology, or timing of life history events, 

of both plant and animal species. These phenological shifts 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 7.1—The Olympic torrent salamander is endemic to the 

Olympic Peninsula and is an example of a species that will likely 

be sensitive to extremes in temperature and precipitation, and 

related changes in hydrology, with climate change. (Photo by 

Betsy Howell, USDA. Forest Service, Olympic National Forest.)

Figure 7.2—The Cascades frog will likely be sensitive to changes 

in hydrology and wetland habitats that occur with climate change 

on the Olympic Peninsula. (Photo by Betsy Howell, USDA Forest 

Service, Olympic National Forest.)

will likely influence wildlife, their food sources, and habitat 

attributes on the Olympic Peninsula. 

Animal life history events that can be affected by 

changing seasonality include emergence from hibernation, 

mating, and migration. Plant species also respond to changing seasonality by shifting the timing of bud break, flowering, and fruiting, and insects respond by varying timing 

of emergence. However, the shifts in timing of life history 

events between trophic levels (e.g., plants, herbivores, 

predators) may not be proportionate or parallel. Varied phenological response to warming between trophic levels could 

result in mismatches in formerly coordinated phenology of 

animals and their food sources, leading to decreasing fitness 

and possibly mortality in some wildlife populations (Both 

et al. 2006, ISAB 2007, Parmesan 2006, Root and Hughes 

2005). For example, for species that have specialized diets 

and carefully balanced energy budgets, such as bats, a shift 

in the timing of invertebrate prey availability could result in 

reduced survival or fecundity. 

Concurrent with a 1.4 °C rise in local temperatures at 

the Rocky Mountain Biological Laboratory in Colorado 

between 1975 and 1999, yellow-bellied marmots began 

emerging from hibernation about 23 days earlier (Inouye 

et al. 2000). However, the flowering plant phenology did 

not shift in that period because warmer temperatures were 

coupled with increased precipitation and snowpack. Thus, 

the change in marmot behavior decoupled the relative 

phenology of marmots and their food plants (Inouye et al. 

2000). Analogous mismatches could occur on the Olympic 

Peninsula. In contrast to the Colorado example, however, 

warmer temperatures on the Olympic Peninsula will likely 

lead to decreased snowpack, regardless of changes in 

precipitation, owing to the relatively warm conditions on 

the peninsula (Elsner et al. 2010). Thus, plant emergence 

and growth could remain synchronous with emergence of 

the Olympic marmot (fig. 7.3) and other hibernating wildlife 

species. Shifts in timing of migration could also impair 

foraging efficiency of some species. For example, some bird 

species are arriving earlier at summer breeding grounds in 

response to warming in the second half of the 20th century 

(Butler 2003, Inkley et al. 2004, Inouye et al. 2000, Sparks 

1999, Tryjanowski et al. 2002). However, food resources at 

summer breeding grounds may not be as available earlier 

in the spring (Inouye et al. 2000) because warming patterns 

differ spatially and species respond individualistically to 

changing climate. 

Changes in seasonality could also influence habitat 

suitability. For example, some amphibians produce eggs and 

move to breeding ponds based on temperature and moisture. 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 7.3—The Olympic marmot is endemic to the Olympic 

Peninsula. Warming temperatures with climate change will likely 

reduce snowpack and alter forage species composition and phenology in the alpine and subalpine habitats that marmots inhabit. 

(Photo by Betsy Howell, USDA Forest Service, Olympic National 

Forest.)

These species may encounter mismatches between breeding phenology, pond drying, and arrival at the pond (WGA 

2008). 

Examples of species shifting phenology in response 

to climate change in the late 20th century are not isolated 

(ISAB 2007). Rather, substantial evidence exists that 

phenological shifts are already underway for a variety of 

plant, animal, and insect species (e.g., Parmesan 2006, 

Parmesan and Yohe 2003, Root et al. 2003, Walther et al. 

2002,). A meta-analysis by Parmesan and Yohe (2003) 

concluded that most of 677 species studied show trends 

toward spring advancement in the last few decades, with 

earlier frog breeding, bird nesting, first flowering, tree 

budburst, and arrival of migrant birds and butterflies. These 

consistent and directional responses to warming of about 

0.6 °C (Pachauri and Reisinger 2007) over the last century 

suggest that there will be even more far-reaching effects on 

species as the climate warms at an increasing rate (Root et 

al. 2003). Although quantitative data on phenological shifts 

on the Olympic Peninsula are lacking, peninsula species 

likely have and will be similarly affected by increasing 

temperatures. 

Distribution shifts—

Species occurrence (range) partially depends on the availability of suitable climatic conditions, along with other 

factors such as habitat suitability, food availability, and 

interactions with other species (MacArthur 1972). Wildlife 

species respond to climate and habitat variability in the 

short term through shifts in geographic range (migration) 

when suitable conditions are not present in the former range. 

Where suitable climates and habitat are no longer present, 

mortality and local population contraction and extirpation 

often occur in parts of a species’ former range (Grayson 

2006). For example, contraction or local population extirpations may occur at the southern end of a species range 

with warming, while at the same time, there are increases 

in northward colonization. Over time, extirpation and 

colonization events cumulatively result in shifts of species’ 

distribution ranges. Shifts in animal species’ geographic 

ranges owing to physiological constraints and changes in 

plant species distribution and habitat structure, as well as 

shifts in the abundance and phenology of associated species 

(competitors, predators, prey, and forage species) will 

interact to determine how climate change affects species 

and communities.

Species ranges will probably move northward and 

to higher elevations as temperature increases (Parmesan 

2006). However, range shifts will depend on factors such 

as degree and speed of vegetation change, specific habitat 

conditions, shifts in distribution of competitors and predators, changes in precipitation patterns, species’ physiological requirements, and species’ differential sensitivity 

and response to various aspects of changing climate (e.g., 

increase in minimum temperature versus maximum 

temperature) (Inkely et al. 2004). The ability of wildlife 

species to disperse or migrate will depend on the availability of migration corridors and suitable habitats, and the 

concurrent movement of forage, prey, and cover (Inkely et 

al. 2004). For example, high-elevation species will likely 

be particularly sensitive to warming temperatures and 

experience range contractions (Moritz et al. 2008) because 

contiguous, higher elevation habitat may not be available 

to colonize. Soil formation at higher elevations is a slow 

process, and vegetation establishment at higher elevations 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

may not occur quickly enough to provide habitat under 

rapid warming. Snowpack at higher elevations may also be 

prohibitive. Similarly, it may be more difficult for endemic 

and specialist species with strict habitat requirements or 

dependencies on specific forage species to find suitable 

habitat conditions under changing climate, whereas generalist species with high climatic tolerance, broad habitat and 

forage requirements and high dispersal ability will likely 

increase in abundance under a changing climate (Pounds et 

al. 2005). Barriers such as topographic features and habitat 

fragmentation could further inhibit potential range shifts 

(Inkley et al. 2004). For example, the Strait of Juan de Fuca 

will inhibit northward movement of terrestrial species on 

the peninsula, although new species could move onto the 

peninsula from the south. 

Recent observed shifts in species ranges are consistent 

with those expected under a warming climate, and examples 

of shifts in species ranges from around the world are numerous (Parmesan 2006, Parmesan and Yohe 2003, Root et al. 

2003, Walther et al. 2002). An analysis of recent range shifts 

of 99 species of birds, butterflies, and alpine herbs in the 

Northern Hemisphere showed an average shift in species’ 

range boundaries of 6.1 km northward or 6.1 m upward in 

elevation per decade (Parmesan and Yohe 2003). Similarly, 

an analysis of 40 years of Audubon Society Christmas Bird 

Count observations showed that 177 of 305 bird species 

seen in North America during the first weeks of winter have 

moved northward (Audubon 2009). The average distance 

moved was 56 km, but more than 60 species moved more 

than 160 km north. Annual altitudinal shifts were correlated 

with annual temperature. 

There is also evidence that small mammals are shifting their ranges in response to warming; an analysis by 

Moritz et al. (2008) in Yosemite National Park showed that 

half of 28 small mammal species monitored over the last 

century shifted their elevation limits upward an average of 

about 500 m, consistent with the observed warming trend 

in the region. As expected, range shifts are associated 

with population losses for some species, and other species’ 

extinctions are attributed to recent climate change (Beever 

et al. 2003; Parmesan 1996; Pounds et al. 1999, 2006). 

Moritz et al. (2008) found that range contractions were more 

likely for high-elevation small mammal species, whereas 

range expansions were more likely for lowland species that 

are short lived and more productive than their long-lived, 

less fecund counterparts.

Some Olympic Peninsula species will probably respond 

similarly to increasing temperature by shifting their ranges 

upward in elevation. The degree and rate of species’ distribution changes will depend on several factors, including 

species’ physiological constraints, the speed and nature of 

vegetation change, habitat suitability, barriers to dispersal, 

and interactions with other species. For subalpine meadow 

and alpine meadow habitat specialists such as the Olympic 

marmot (fig. 7.3), western heather vole, and Olympic pocket 

gopher, there may not be any suitable habitat conditions 

available at higher elevations. These species are found at 

the highest elevations of many ridge systems; on other 

ridge systems or mountains, these species will not be able 

to survive unless snowpack is sufficiently low in summer 

and deep soils and meadow vegetation develop. However, 

declines in snowpack with warming will be lower at the 

highest elevations (>2000 m): (Elsner et al. 2010), and soil 

development may take decades to centuries. Furthermore, 

it is not clear if these rodents will be able to establish new 

populations if there are barriers to their dispersal.

Biotic interactions—

As species individualistically shift their ranges in response 

to a warming climate, novel predator-prey interactions and 

new interspecific interactions will develop among species (ISAB 2007, Schmitz et al. 2003). Predicting future 

interspecific interactions is very difficult, although clearly 

new interspecific interactions, as with all climate change 

effects, will positively affect some species and populations, 

and negatively affect others. For example, movement of a 

predator out of portions of a prey species’ range will allow 

the prey species to expand but may reduce predator fitness owing to decreased prey availability. In contrast, the 

movement of a predator into new areas could negatively 

affect prey species. The range expansion of the coyote into 

high-elevation areas on the peninsula, for example, may 

be having a negative impact on Olympic marmot (fig. 7.3) 

populations (Griffin et al. 2008, Witczuk 2007). Bobcat 
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GENERAL TECHNICAL REPORT PNW-GTR-844

populations could have similar effects on prey species if 

they begin spending more time at higher elevations with 

warming temperatures and reduced snowpack. Movement 

of competitors could also influence species abundance 

and viability. Although not necessarily related to climate 

change, the negative influence of the barred owl (native 

to North America but relatively new to western North 

America) on the specialist northern spotted owl is a good 

example of how new competitive interactions can lead to 

pronounced effects on species distributions and viability 

(Kelly et al. 2003). 

Changes in interspecific interactions with climate 

change will include changing interactions with exotic 

species, as well as pests and pathogens. New exotic species will likely establish with changing climatic conditions 

(Hellmann et al. 2008). Some existing exotic species will 

likely expand with climate change, because ecosystem 

disturbance and shifts in native species ranges will provide 

opportunities for exotic establishment. Some exotic species 

are invasive, with characteristics that facilitate their expansion and dominance under changing climate, such as broad 

climatic tolerances and high dispersal ability (Hellmann et 

al. 2008). 

Parasites, pests, and pathogens are also expected to 

respond to climate change. Forest pests and pathogens 

could have widespread effects on wildlife habitat quality 

on the peninsula (see chapter 6 for more details). Increased 

temperatures and moisture at mid-latitudes could accelerate parasite vector and pathogen life cycles, improve 

survival by relaxing overwintering restrictions, and lead to 

northward expansion of tropical and subtropical pathogens 

(Harvell et al. 2002, Inkley et al. 2004). Shifting ranges of 

wildlife species will lead to new disease exposures (Brooks 

and Hoberg 2007), and shifts in parasite vectors will introduce new diseases (Kovats et al. 2001, WGA 2008). Climate 

warming can also increase host susceptibility to diseases 

(Harvell et al. 2002). Increases in parasites and infectious 

diseases associated with climate change have the potential 

to influence the size of wildlife populations and accelerate 

species extinctions (Harvell et al. 2002, WGA 2008). 

Interaction with other stressors—

Climate change will not act alone in influencing wildlife 

populations on the Olympic Peninsula in the coming 

decades. Instead, climate change will act synergistically 

with other stressors to affect wildlife populations (Inkley 

et al. 2004, WGA 2008). Current stressors that influence 

wildlife on the peninsula and many ecosystems across the 

Western United States include land use legacies, ongoing 

habitat loss and fragmentation, altered disturbance regimes, 

disease, and exotic species. Land use changes and introduction of exotic species can impede the ability of species to 

adaptively respond to climate change (Hansen and DeFries 

2007). For instance, many land use changes impose barriers 

to species’ migration to favorable new environments, small 

population sizes and isolation resulting from land uses 

impedes gene flow, and landscape fragmentation reduces 

corridors for movement (Joyce et al. 2008). At Olympic 

National Forest (ONF), historical widespread logging activity reduced the area of late-successional forest and isolated 

existing late-successional forest patches, which could 

impede adaptive response of species with low dispersal 

ability. Highways and land converted to agricultural, 

residential, or industrial uses further fragments the Olympic 

Peninsula. The spread of exotic species on the peninsula 

may cause a reduction in forage plants on which some 

wildlife species depend, thus making it more difficult for 

these species to respond adaptively to climate change. These 

interactions increase uncertainty and complicate actions 

to mediate climate change effects, but also suggest that 

treatment of other stressors (e.g., exotic species and habitat 

fragmentation) may help alleviate the negative effects of 

climate change.

Potential Genetic Responses to Climate Change

It is possible that wildlife species will respond to changing 

climate through genetic change. However, the expected 

rates of increase in temperature with climate change are 

greater than those of the past, making it difficult to predict 

genetic response (ISAB 2007). Evidence exists for adaptive 

genetic change in some species in response to changing climate, including mosquitoes, fruit flies, birds, and squirrels 

(Bradshaw and Holzapfel 2006, ISAB 2007). The adaptive 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

genetic changes all involved adaptation to the timing of 

seasonal events or to season length (Bradshaw and Holzapfel 2006). In mosquitoes, which have the shortest generation 

times of this group, evolutionary change occurred in as little 

as 5 years. Changes for squirrels and birds were smaller and 

became apparent only over longer periods (10 to 30 years), 

suggesting that larger and longer lived species may experience population decline or be replaced by other species 

(Bradshaw and Holzapfel 2006). Habitat fragmentation 

and resulting population isolation that prevents gene flow 

is a barrier to this type of genetic response. Although such 

evolutionary responses occur, there is little evidence that the 

responses are of the type or magnitude to prevent species 

extinctions (Parmesan 2006), because the rate and magnitude of climate change may overwhelm a species’ capacity 

for genetic change (Barnosky and Kraatz 2007). 

Potential Climate Change Effects on Olympic 

Peninsula Habitats

Related to the potential direct and indirect effects of climate 

change on wildlife, there are also many potential climate 

change effects on wildlife habitats on the Olympic Peninsula. A description of potential effects of climate change on 

Olympic Peninsula habitat types and related species follows 

(see chapter 6 for more detailed information on potential 

vegetation changes). 

Varied climatic conditions on the peninsula result in 

highly varied ecological communities, and thousands of 

years of geographic isolation have resulted in fauna that are 

distinct from those in the Cascade Range to the east. There 

are several endemic wildlife species, including the Olympic 

marmot (fig. 7.3), the Olympic pocket gopher, and Roosevelt 

elk. Wildlife on the Olympic Peninsula is noteworthy not 

only for its endemic species, but also for species missing 

from the Olympics yet found elsewhere in western mountains, including American pika, white-tailed ptarmigan, 

ground squirrels, Canada lynx, red fox, wolverine, grizzly 

bear, and bighorn sheep. Historically, mountain goats and 

coyote did not occur on the Olympic Peninsula. 

Glaciers and snowfields—

At the highest elevations on the Olympic Peninsula, warming temperatures will likely cause loss of snowpack and 

snowfields and recession of glaciers (Elsner et al. 2010). The 

greatest effects of reduced snowpack and glacial recession 

will be hydrologic; loss of glaciers, decreased snowpack, 

and earlier snowmelt with warming temperatures will 

reduce water availability in summer months in glacier- and 

snowmelt-fed streams, lakes, and wetlands (Elsner et al. 

2010). Although glaciers and snowfields currently provide 

habitat for only a few species, such as the gray-crowned 

rosy finch, the loss of snowpack with warming may allow 

vegetation establishment in these areas, leading to improved 

habitat conditions for other high-elevation wildlife species. 

In the short term, vegetation establishment will be limited 

to areas with substrate that is favorable to rapid soil development, such as shallow-gradient slopes with deep layers 

of fine-grained glacial till. The more rocky (scree, talus, 

boulder) areas from which snow or glaciers retreat will not 

be hospitable to soil development in the short term. 

Alpine tundra—

Alpine tundra provides seasonal habitat for a variety of 

wildlife species on the Olympic Peninsula, including 

Roosevelt elk, North American black bear, and the western 

heather vole (table 7.1). Similar to effects on glaciers and 

snowfields, warming temperatures will likely reduce snowpack and cause earlier snowmelt in alpine tundra habitats. 

These conditions could favor tree establishment, provided 

that the soils in tundra areas can sustain trees. Several 

paleoecological studies show the expansion of subalpine fir 

into alpine tundra in the northeastern portion of the Olympic Peninsula during historically warm periods (Brubaker 

and McLachlan 1996, Gavin et al. 2001, McLachlan and 

Brubaker 1995). Warmer temperatures and increased tree 

establishment may lead to loss of tundra habitat (see MC1 

model output in chapter 6). The paleoecological record does 

not provide evidence that the highest (>1800 m in elevation) 

alpine habitats underwent great change during past warm 

periods (Gavin et al. 2001, McLachlan and Brubaker 1995), 

suggesting that only high levels of warming (>1–2 °C) may 

result in major changes in the highest alpine areas. However, anthropogenic climate change may be characterized 

by more extreme temperature increases than past warming 

periods, and warming greater than 1.0 to 2.0 °C is projected 
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Table 7.1—Olympic Peninsula habitat types, generally from highest to lowest elevation, and associated 

species most likely to be influenced by climate change and related changes in habitata

Habitat type Associated species likely to be influenced by climate-induced habitat changes

Alpine tundra Black bear, mountain goat, Olympic marmot, Olympic pocket gopher, Roosevelt elk, 

western heather vole 

Talus fields Gray-crowned rosy finch

Subalpine Black bear, bobcat, coyote, mountain goat, snowshoe hare, Clark’s nutcracker

Wet meadows Black bear, coyote, Olympic marmot, Roosevelt elk, western heather vole, dog star 

skipper butterfly

Dry meadows Black bear, coyote, Olympic marmot, Olympic pocket gopher, Roosevelt elk, dog star 

skipper butterfly, Taylor’s checkerspot butterfly

Montane forest American marten, black bear, bushy-tailed woodrat, coyote, mountain beaver, northern 

flying squirrel, Pacific fisher, Roosevelt elk, snowshoe hare, barred owl, Northern 

spotted owl, ensatina 

Lowland forest American marten, black bear, bushy-tailed woodrat, coyote, mountain beaver, northern 

flying squirrel, opossum, Pacific fisher, porcupine, Roosevelt elk, barred owl, marbled 

murrelet, northern spotted owl, northern alligator lizard, ensatina, Van Dyke’s 

salamander, warty jumping slug

Riparian and flood-plain habitat Pacific fisher, American dipper, hairy woodpecker, harlequin duck, hooded merganser, 

red-breasted sapsucker, wood duck, chorus frog, red-legged frog, Van Dyke’s 

salamander, western toad, warty jumping slug

Lakes, wetlands, and bogs Garter snake, Cascades frog, long-toed salamander, northwestern salamander, western 

toad, Makah copper butterfly

Prairies and balds Roosevelt elk, American kestrel, pallid horned lark, dog star skipper butterfly, Taylor’s 

checkerspot butterfly

Caves and mines Keen’s myotis bat, little brown bat

a

 Species are grouped by vertebrate phylogenetic class (mammals, birds, reptiles, amphibians) and invertebrates, and listed alphabetically within group. 

The species included in this table were identified by Olympic National Forest; Olympic National Park; Forest Service, Pacific Northwest Research 

Station; and U.S. Geological Survey specialists as being high profile or most likely to be influenced by climate change, or both. This is not an exhaustive 

list of species that will be influenced by climate change on the peninsula.

to occur in the Pacific Northwest by the middle to late part 

of the 21st century (Mote and Salathé 2010). Even in the 

persistent alpine tundra habitats, increased summer drought 

could decrease berry production, likely causing reduced 

fitness of berry-dependent species such as North American 

black bear. Decreased berry production and berry crop 

failures may also force species such as black bear to search 

for other food sources, which could bring them into greater 

conflict with humans. 

Talus fields—

Decreased snowpack and earlier snowmelt will likely cause 

changes in microenvironments in talus fields, particularly 

decreased moisture in the later parts of the growing season. 

However, cover of talus fields may increase with decreased 

snow cover, providing additional habitat for species such as 

the gray-crowned rosy finch (table 7.1). 

Subalpine habitat—

Subalpine habitats on the Olympic Peninsula will likely 

experience decreased snowpack and earlier snowmelt with 

warming temperatures. These conditions will cause changes 

in vegetation community composition, with likely increases 

in tree establishment and growth, and thus loss of meadow 

habitat. Mortality of whitebark pine caused by white pine 

blister rust, and potentially by climate-induced outbreaks 

of mountain pine beetle (see chapter 6), will impact species 

that depend on whitebark pine, most notably the Clark’s 

nutcracker (fig. 7.4). 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Figure 7.4—Species such as the Clark’s nutcracker that depend 

on whitebark pine will be impacted by mortality of whitebark 

pine caused by white pine blister rust, and potentially by climateinduced outbreaks of mountain pine beetle. (Photo courtesy of 

USDA Forest Service, Olympic National Forest.)

Figure 7.5—Taylor’s checkerspot butterfly is a federally listed 

sensitive species that uses meadow and prairie habitat on the 

Olympic Peninsula. (Photo by Betsy Howell, USDA Forest 

Service, Olympic National Forest.)

Figure 7.6—Cope’s giant salamander inhabits headwater streams 

and may be affected by decreased summer low flows on the 

Olympic Peninsula with climate change. (Photo by Betsy Howell, 

USDA Forest Service, Olympic National Forest.)

Meadows—

Wet meadow habitat, which occurs primarily in high snow 

areas on the west side of the Olympic Peninsula, will likely 

decrease with warming because of changes in hydrology 

(decreased snowpack and earlier snowmelt leading to earlier 

runoff and increased summer drought). Decreases in this 

habitat could influence wet meadow-dependent species, 

such as the western heather vole (table 7.1). However, dry 

meadow habitat, which occurs primarily in the rainshadow 

in the northeastern portion of the Olympic Peninsula, 

may increase with increased fire frequency and increased 

drought limitations on tree species distribution (Littell et 

al. 2010). Increased area of dry meadows could provide 

additional habitat for species such as the Olympic marmot 

(fig. 7.3), Olympic pocket gopher, and Taylor’s checkerspot 

butterfly (fig. 7.5) (table 7.1). Alternatively, upward-elevation shifts in tree line could result in tree encroachment of 

meadows and decreased meadow habitat. Also, increased 

temperatures may lead to changes in species composition in 

both wet and dry meadows, with the potential for increases 

in exotic species. 

Montane forests—

Montane forest habitats on the Olympic Peninsula, including forests dominated by Pacific silver fir, Douglas-fir, 

and western hemlock, will likely experience a variety of 

changes with a changing climate. Reduced snowpack and 

more precipitation falling as rain rather than snow will 

shift the timing of runoff and increase summer drought 

(Elsner et al. 2010), and thus potentially decrease the area 

of headwater riparian habitat in montane forests. Decreases 

in headwater habitat could influence species that depend on 

this habitat, such as the Olympic torrent salamander (fig. 

7.1) and Cope’s giant salamander (fig. 7.6). Increased summer drought and reductions in soil moisture could influence 

species such as the mountain beaver (fig. 7.7) that require 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 7.7—Increased summer drought and reductions in soil 

moisture with climate change could influence species such as the 

mountain beaver that require moist soils for digging burrows. 

(Photo by Betsy Howell, USDA Forest Service, Olympic National 

Forest.)

moist soils for digging burrows (table 7.1). Changes in 

hydrology may also affect seeps and springs, which provide 

critical habitat for peninsula species such as Van Dyke’s 

salamander and the Olympic torrent salamander (table 7.1). 

Increased temperatures with climate change will likely 

lead to shifts in plant species distribution, influencing the 

composition and thus habitat characteristics of montane 

forests on the Olympic Peninsula. Species such as western 

hemlock and Douglas-fir will likely increase in abundance 

in forests currently dominated by Pacific silver fir. Species such as Douglas-fir and lodgepole pine may increase 

in abundance in forests currently dominated by western 

hemlock and Douglas-fir. Changes in species phenology, 

and related changes in production of wildlife food sources 

such as berries, will likely influence the quality of habitat 

provided by montane forests for species such as the North 

American black bear. Increased frequency of disturbances, 

such as fire, insect outbreaks, wind events, and drought, 

will also influence montane forest habitat. Initially (and 

without management intervention) increased disturbance 

frequency will likely lead to increases in snags and coarse 

woody debris, which will benefit some species such as 

birds, amphibians, and mammals that use these habitat 

elements. Drought- and fire-induced reduction in forest 

density may lead to more open-canopied forests and larger 

residual trees. However, repeated fires may eventually lead 

to a reduction in legacy structures and an increase in early 

seral forest, with negative consequences for species that 

rely on large trees and mature forest conditions, such as the 

northern spotted owl and marbled murrelet. 

Prairies and balds—

Some prairies on the Olympic Peninsula were created and 

maintained by Native American burning (Peter and Shebitz 

2006). Without fire, tree and shrub encroachment can 

reduce prairie habitat quality. Increased fire with 

warming on the peninsula may increase the quality of 

prairie habitat for dependent species such as the Taylor’s 

checkerspot butterfly (fig. 7.5). However, increased temperatures could also lead to changes in plant species composition, with the possibility of increased exotic species and 

reduced habitat quality. 

The presence of balds on the Olympic Peninsula is 

primarily controlled by edaphic conditions; balds largely 

exist in areas where soils are too shallow and dry to support 

trees (Chappell 2006). Increased fire frequency with climate 

change could increase the area of balds by killing small 

young trees on the margins (Chappell 2006). However, 

increased drought and fire frequency associated with climate change may also affect composition in the unique and 

relatively species-rich plant communities that inhabit balds, 

possibly increasing establishment of exotic species. 

Lowland forests—

Similar to the outlook for montane forests, a variety of 

potential effects of climate change may occur in lowland 

forests of the Olympic Peninsula, including forests dominated by Douglas-fir, western hemlock, and Sitka spruce. 

Climate-induced changes in hydrology, phenology, forest 

species composition, and increased disturbance will affect 

these lowland forests. Increased drought could decrease 

forest productivity in lowland forests and increase abundance of more drought-tolerant species, such as Douglas-fir 

and western redcedar. Also, projected increases in winter 

precipitation and precipitation intensity on the peninsula 

(Elsner et al. 2010, Salathé et al. 2010) and the effects on 

hydrologic regimes (see chapter 4) will affect lowland 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

forests through increased frequency and magnitude of 

flooding and disturbance in riparian areas (scouring, 

removal of off-channel areas, deposition, and transport of 

woody debris). The current prevalence of exotic plant 

species in this forest type on the peninsula, coupled with 

projections for increased disturbance, suggest that exotics 

may become even more common with climate change in 

lowland forests. Because some exotic plants are also invasive and can outcompete native species on which wildlife 

species depend, an increase in exotic plants may have 

negative consequences for some wildlife species. 

Increases in disturbances such as wind events and 

flooding may decrease the area of late-successional forests, 

on which species such as the northern spotted owl and marbled murrelet depend. However, increased disturbance may 

also lead to increased abundance of sprouting deciduous 

hardwoods, such as red alder and bigleaf maple, which can 

provide nesting and foraging habitat for some woodpecker 

species and Neotropical migrants, as well as leaf litter that 

increases habitat quality for some mollusks and salamander 

species. Increased disturbance and drought may also lead 

to increased abundance of mast-producing species, such as 

Pacific madrone and Oregon white oak (see chapter 6). 

Riparian habitat—

As described above, altered hydrologic regimes will likely 

increase flood frequency and disturbance in riparian areas. 

Additional scouring, sediment deposition, and transport of 

woody debris from flooding will influence habitat characteristics in streams and adjacent riparian forests. Increased 

flooding severity may decrease flood-plain complexity and 

sinuosity of rivers, thereby reducing flood-plain habitat 

complexity and habitat quality for amphibian species. 

Increased disturbance frequency and severity in riparian 

areas could also reduce the area of mature riparian conifer forests and increase area of younger riparian forests 

dominated by deciduous hardwoods, which could degrade 

habitat quality for some birds and other species that use 

older conifers. However, deciduous hardwoods can provide 

valuable nesting habitat for cavity-nesting ducks and nesting and foraging habitat for some woodpecker species and 

Neotropical migrant birds. 

Besides increased flooding, changes in hydrology with 

climate change will exacerbate summer drought, reduce 

streamflow, and produce drier conditions in adjacent 

riparian areas. These increases in extremes (both flooding 

and drought) may make riparian and flood-plain habitat 

less hospitable for wildlife species, such as the Pacific 

chorus frog, western toad, and red-legged frog (table 7.1). 

More frequent disturbance may also make these areas more 

prone to exotics, such as Japanese knotweed, which may 

outcompete native species and influence habitat quality 

for species such as songbirds. However, increased heat and 

drought may improve habitat for some species, such as the 

northern alligator lizard, because the peninsula is currently 

a relatively cool environment, and reptiles rely on the 

environment to warm themselves. 

Lakes, wetlands, and bogs—

Reduction in snowpack and changes in timing of runoff 

with warmer temperatures will likely lead to drying of 

some wetland habitats, such as alpine ponds and wetlands, 

reducing habitat quality for dependent species such as the 

Cascades frog (fig. 7.2), northwestern salamander, long-toed 

salamander, and garter snakes. Wildlife species that depend 

on wetlands may be particularly sensitive to changing 

habitat conditions with climate change because there is little 

opportunity for migration to other suitable habitat (Burkett 

and Kusler 2000). 

Cliffs, caves, and mines—

Increases in air temperatures with climate change could 

affect the temperatures of cliff habitats, thus affecting nesting conditions for birds that rely on cliff habitats. However, 

cave and mine habitats, along with other forest structures 

with similar microclimates, will likely remain thermal 

refugia, and for this reason, may become more important 

with climate change. 

Wildlife and Habitat Management at 

Olympic National Forest and Olympic 

National Park

This section provides information on wildlife and habitat 

management at ONF and ONP, including (1) the context 

in which ONF and ONP manage wildlife and habitat, 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Table 7.2—Federally listed threatened (T) and endangered (E), and state 

(WA-S) and federally listed sensitive (S) terrestrial wildlife species on 

the Olympic Peninsulaa

Common name Scientific name Status

Townsend’s big-eared bat Corynorhinus townsendii S

Olympic marmot Marmota olympus WA-S

Pacific fisher Martes pennanti S

Keen’s myotis Myotis keenii WA-S

Olympic pocket gopher Thomomys mazama melanops WA-S

Marbled murrelet Brachyramphus marmoratus T

Common loon Gavia immer WA-S

Bald eagle Haliaeetus leucocephalus S

Harlequin duck Histrionicus histrionicus S

Northern spotted owl Strix occidentalis caurina T

Cope’s giant salamander Dicamptodon copei S

Van Dyke’s salamander Plethodon vandykei WA-S

Olympic torrent salamander Rhyacotriton olympicus WA-S

Johnson’s hairstreak butterfly Callophrys johnsoni S

Puget Oregonian snail Cryptomastix devia S

Evening fieldslug Deroceras hesperium S

Taylor’s checkerspot butterfly Euphydryas editha taylori S

Keeled jumping-slug Hemphillia burringtoni WA-S

Warty jumping-slug Hemphillia glandulosa S

Malone jumping-slug Hemphillia malonei WA-S

Oregon megomphix mollusk Megomphix hemphilli WA-S

Olympic arctic butterfly Oeneis chryxus valerata WA-S

Dog star skipper Polites sonora siris WA-S

Blue-gray taildropper slug Prophysaon coeruleum WA-S

Hoko vertigo snail Vertigo n. sp. (new unnamed species) WA-S a Species are grouped by vertebrate phylogenetic class (mammals, birds, reptiles, amphibians) and 

invertebrates, and listed alphabetically by scientific name within group.

(2) guidance and constraints on wildlife and habitat 

management at ONF and ONP, and (3) the primary issues 

around and activities currently conducted in wildlife and 

habitat management at ONF and ONP. This information, 

coupled with the likely effects of climate change on wildlife 

and their habitats on the Olympic Peninsula (described 

above), provide a basis on which to develop climate change 

adaptation options for wildlife and habitat management at 

ONF and ONP. 

Policy Guidance and Goals

Both ONF and ONP manage wildlife habitat to maintain 

biodiversity, prevent extinctions of native species that are 

federally listed as threatened or endangered, and maintain 

healthy populations of all native species. Olympic National 

Forest manages wildlife habitat under the direction of the 

Northwest Forest Plan (NWFP) (USDA and USDI 1994) and 

the 1990 Olympic Land and Resource Management Plan 

(USDA FS 1990). At ONF, a major land allocation under the 

NWFP is the late-successional reserve (LSR) allocation in 

which the goal is to maintain interactive, late-successional 

and old-growth forest ecosystems. A fundamental goal of 

LSRs is to provide habitat for late-successional and oldgrowth-related species, including the northern spotted owl. 

Other goals for managing wildlife habitat at ONF include 

maintaining biodiversity and sufficient habitat to ensure 

viable populations and prevent extinctions of all native 

species. Special attention is given to native species that 

are federally listed as threatened, endangered, or sensitive 
103

Adapting to Climate Change at Olympic National Forest and Olympic National Park

(TES) or classified as sensitive under the Pacific Northwest 

regional forester’s sensitive species program (table 7.2). 

Besides managing for TES species, ONF manages 

for species classified as management indicator species. 

Indicator species are chosen to reflect an assemblage of 

species having similar habitat or ecosystem affinities and 

requirements, with an assumption that management that 

maintains or enhances the habitat of indicator species will 

also benefit the larger assemblage of species. Seven species, 

or groups of species, have been selected as indicators at 

ONF. These include primary excavators as indicators for 

snag-dependent cavity nesters; Roosevelt elk and Columbia 

black-tailed deer as game species indicators; American 

marten and pileated woodpecker as mature coniferous forest 

species indicators; northern spotted owl as an old-growth 

forest species indicator; and bald eagle as a riparian/mature 

forest species indicator. Additional management direction 

guides habitat maintenance for game species. The park’s 

wildlife management program promotes sustaining a full 

range of natural genetic variability and long-term viability 

through maintenance of wildlife population age-structures, 

abundance, density, and distributions within normal ranges. 

When adequate habitat exists and several additional 

criteria are met, National Park Service management policies 

(NPS 2006) direct park managers to restore extirpated 

native species such as the Pacific fisher, which is believed to 

have been extirpated from the state of Washington. In 1988, 

the Pacific fisher was listed as a state endangered species in 

Washington state, and in 2004 as a federal candidate species 

(west coast distinct population segment). In 2004, the Washington State Department of Fish and Wildlife completed 

a feasibility study, concluding that the Olympic Peninsula 

was best suited as a release site for the initial restoration of 

Pacific fisher to the state. In 2008, a multiyear, interagency 

program began to restore Pacific fishers to the Olympic 

Peninsula, with releases over a 3-year period in ONP. This 

program also addressed a National Park Service policy 

objective of restoring a full complement of native species 

to ONP. At present, the only native species absent from 

the park is the gray wolf. Although there are no current 

proposals to reintroduce the wolf, the return of wolves could 

influence populations and distributions of herbivores, which 

would affect riparian vegetation communities (Beschta 

and Ripple 2008), and potentially ecosystem resiliency to 

climate change. 

Habitat Improvement and Restoration Activities

Activities to improve wildlife habitat quality at ONF 

include snag and coarse wood creation, pruning, cavity 

treatments, forage plantings, and mechanical treatments 

to maintain open habitats. Snag creation, often conducted 

in thinning treatments, can include blasting or removing 

the tops of trees with chain saws, inoculation with local 

stem decay fungi, or girdling. Biologists also install nest 

boxes for northern flying squirrels. Coarse wood treatments 

include creating furrows in felled trees, piling fine or coarse 

downed wood, and bundling logs together from felled 

trees to create coarse wood structures. Pruning treatments 

include pruning of understory shrubs or hardwood trees to 

stimulate sprouting and increase availability of big game 

browse or suitability for shrub-nesting birds. Treatments 

include creating artificial cavities in topped or live trees 

to benefit cavity-using wildlife. Forage plantings for large 

game include planting willow and red-osier dogwood. 

Mechanical treatments (chain saws and loppers) include 

removing salmonberry and some small conifers from areas 

that were once meadow or openings created from earlier 

management practices.

Within ONF, road decommissioning and culvert installation improve habitat for fish and aquatic species, as well as 

some terrestrial wildlife species. For example, road decommissioning and culvert installation can improve water quality and access to habitats for species that have an aquatic 

phase, such as the Olympic torrent salamander (fig. 7.1), 

tailed frog, and Cope’s giant salamander (fig. 7.6). Many 

vegetation management activities (described in chapter 6) 

can also be considered wildlife habitat restoration activities 

at ONF. For example, thinning in young stands (40 to 80 

years old) focuses on creating forest structural diversity 

intended to accelerate the development of late-successional 

forest characteristics used by old-growth-dependent species 

such as the northern spotted owl and marbled murrelet. 

Young plantations that are proximal to old-growth forests 

receive priority for thinning treatments to increase the area 
104

GENERAL TECHNICAL REPORT PNW-GTR-844

of contiguous old-growth habitat. Habitat improvement for 

Roosevelt elk is also a factor in setting priorities for thinning. Wildlife habitat provisions in silvicultural prescriptions focus on snag and coarse woody debris density and 

distribution at the watershed scale. 

Olympic National Park works to restore ecosystems, 

habitats, and disturbance regimes altered by human 

activities or exotic species. As the park acquires private 

properties from willing sellers within the park boundaries, 

biologists work to restore these sites by planting native 

species propagated from adjoining areas. 

Within aquatic systems of the park, management 

priorities include pollution prevention, protection of riparian 

and lake habitat, and water quality maintenance to meet the 

needs of aquatic organisms. A major restoration effort is 

underway to remove two dams from the Elwha River. Dam 

removal will occur over a 2-year period beginning late in 

2011, with active fish and vegetation restoration projects 

occurring during several years thereafter. After this restoration project, the river will support all five species of Pacific 

salmonids that inhabited the river before dam construction. Succession of riparian communities over the next 

several years to decades will provide habitat for a variety 

of mammals and birds. In preparation for dam removal, 

biologists conducted baseline surveys in the Elwha valley to 

assess occurrence and distribution of North American black 

bear, riparian carnivores, small mammals, beavers, otters, 

amphibians, and birds. Prior studies on prey base adequacy 

for wolves examined Roosevelt elk and Columbia blacktailed deer distribution and density in the Elwha and other 

drainages in the park (Jenkins and Manley 2008). 

Surveys and Monitoring

The ONF conducts surveys to assess wildlife populations on 

the forest. Surveys for wildlife species by ONF personnel 

in the last decade have generally focused on species listed 

as sensitive and included aerial surveys for bald eagles, 

documenting nesting success, and also searching for new 

nests. In 2009, the forest began the first formal surveys for 

Taylor’s checkerspot butterfly (fig. 7.5). Biologists conduct 

surveys for other species opportunistically and sometimes 

not to any strict protocol. There is also documentation of 

egg masses, larvae, and adult pond breeding amphibians in 

some areas, as well as surveys for the northern goshawk. 

The forest installed remote cameras to monitor the recently 

reintroduced Pacific fisher on the peninsula and is working with ONP, the Washington State Department of Fish 

and Wildlife, the U.S. Geological Survey, and the Forest 

Service Pacific Northwest Research Station to establish a 

survey protocol for Pacific fisher. Annual bat surveys in one 

portion of the ONF include bridge and building inspections 

to document use by Townsend big-eared bat and Myotis 

species. 

Forest staff discontinued surveys for marbled murrelet 

and northern spotted owl in the late 1990s after the forest 

began to switch its harvest program to second-growth 

stands instead of old growth. However, the Forest Service 

Pacific Northwest Research Station oversees the Olympic 

Demography Study, which involves annual surveys by 

scientists at selected northern spotted owl activity centers 

on the forest. Olympic National Park biologists conduct 

surveys for northern spotted owl within the park boundaries 

at about 50 sites. Annual survey data from this work dates 

to the early 1990s.

Olympic National Park protects the largest population 

of Roosevelt elk in its natural environment in the world. 

Decades of protection from human harvest and habitat 

manipulation not only sustained high densities of elk, but 

also preserved the natural composition, social structure, and 

dynamics of this unique coastal form of elk found nowhere 

else. Population surveys and other studies of park elk populations since 1985 documented that herds on the west side of 

the park generally reside for most of the year wholly within 

the park, whereas east-side herds spend a portion of the year 

out of the park (Houston et al. 1987, 1990). Understanding 

these differences may be even more important with climate 

change as biologists work across boundaries to conserve 

species and their habitats. 

Biologists monitor elk populations at ONP as a part 

of the National Park Service North Coast and Cascades 

Network monitoring program. Other components of the 

monitoring program address plant communities, landscape 

change, climate, high-elevation lakes, fish in large rivers, 

and land birds. Monitoring protocols are peer reviewed, and 
105

Adapting to Climate Change at Olympic National Forest and Olympic National Park

each includes a data management component. Additional 

monitoring addresses northern spotted owls (and the barred 

owl invasion), and water quality at Lake Crescent. When 

project funds can be obtained, biologists monitor mountain 

goat populations, with at least five surveys completed since 

1983. Long-term research has been, or is being conducted, 

on terrestrial, lotic, and lentic amphibians, Olympic marmot 

(fig. 7.3), North American black bear, Columbia black-tailed 

deer, marbled murrelets, and bald eagles (Weber et al. 2009).

Adapting Wildlife and Habitat Management 

to Climate Change at Olympic National 

Forest and Olympic National Park

Process Used to Develop Adaptation Strategies 

for Wildlife and Habitat Management

During 2009, a series of three workshops was held to 

discuss potential effects of climate change on Olympic 

Peninsula wildlife species and habitats, examine anticipated 

wildlife sensitivities to climate change, and develop potential adaptation strategies and actions for wildlife management at ONF and ONP. Workshop participants included 

natural resources staff from ONF and ONP, specialists from 

the Washington Department of Natural Resources and U.S. 

Fish and Wildlife Service, and scientists from the Forest 

Service Pacific Northwest Research Station, U.S. Geological 

Survey, and University of Washington.

The first workshop focused on potential climate change 

effects on wildlife on the peninsula, including general 

climate change effects, as well as effects anticipated within 

each Olympic Peninsula habitat type. Based on the anticipated climate change effects, participants identified species 

on the peninsula most likely to be impacted by climate 

change (table 7.1). 

Participants in the first workshop concluded that further 

analysis of Olympic Peninsula wildlife species sensitivity 

to climate change would be useful in developing climate 

change adaptation strategies and actions for wildlife habitat 

management at ONF and ONP. During a second meeting, biologists participated in a climate change sensitivity 

assessment process for select wildlife species on the 

Olympic Peninsula, applying methods developed by Joshua 

Lawler (School of Forest Resources, University of Washington). The climate change sensitivity assessment involved 

wildlife experts answering a series of questions about a 

particular species based on their knowledge and experience. 

Participants were asked to (1) classify a species’ maximum 

annual dispersal; (2) determine whether barriers to dispersal 

exist for a given species; (3) rate a species’ dependence 

on disturbance regimes; (4) rate a species’ dependence on 

other species (i.e., interspecific dependencies); (5) rate a 

species’ physiological sensitivity to temperature; (6) rate 

a species’ sensitivity to changing precipitation; (7) rate a 

species’ sensitivity to salinity, pH, and carbon dioxide; (8) 

classify a species reproductive strategy (on an r-selected to 

K-selected scale); and (9) identify any sensitive habitats that 

a given species occupies (see table 7.3 for specific questions). An automated electronic system collected and tallied 

responses and provided summary results to participants. 

Participants then rated how confident they were in the 

summary response, thus quantifying the degree of certainty 

in the group response to a given question. In addition, each 

participant subjectively rated each species’ overall sensitivity to climate change. 

Participants completed the sensitivity assessment for 

a limited number of species during the workshop, and 

individual experts conducted additional species assessments 

through an online database after the workshop. A sensitivity 

score for each species incorporated mean group responses 

from the workshop as well as responses from individuals in 

the online database. An additive function (sum scores for 

each question) (table 7.3), divided by the maximum possible score, and multiplied by 100) produced the sensitivity 

scores, on a 0 to 100 scale. Figure 7.8 illustrates results of 

the sensitivity assessment for the 21 Olympic Peninsula 

species analyzed by the group, as discussed below. 

A third meeting focused on development of adaptation 

strategies and actions for wildlife management at ONF and 

ONP. Objectives of this third workshop were to (1) review 

Olympic Peninsula wildlife habitat and species sensitivities 

to climate change identified in the first two workshops and 

(2) through an interactive dialogue between scientists and 

managers, use the latest scientific information on climate 

change and impacts to wildlife to develop adaptation 
106

GENERAL TECHNICAL REPORT PNW-GTR-844 Table 7.3—Questions posed to participants in the process used to assess the sensitivity of wildlife species to climatea Question 1. Maximum annual dispersal distance for this species is: (0) N/A (1) >100 km (2) 75–100 km (3) 50–75 km (4) 25–50 km (5) 5–25 km (6) 1–5 km (7) <1 km Question 2. Do barriers to dispersal exist? Are there landscape elements that would prevent this species from moving in response to climate change? (0) No (3) Yes Question 3. How dependent is this species on one or more disturbance regimes? (1) not dependent on the (2) slightly (3) somewhat (4) moderately (5) more (6) definitely (7) highly dependent on nature of any disturbance dependent dependent dependent dependent dependent the nature of one or more regime disturbance regimes Question 4. Broadly, where does this species fall on the spectrum of generalist to specialist? (0) N/A (1) generalist (2) (3) (4) (5) (6) (7) specialist

Question 5. Species' sensitivity to temperatureb

:

(0) N/A (1) low (2) (3) (4) (5) (6) (7) high

sensitivity sensitivity

Question 6. Species' sensitivity to precipitationc

:

(0) N/A (1) low (2) (3) (4) (5) (6) (7) high

sensitivity sensitivity

Question 7. Species' sensitivity to salinityd: 

(0) N/A (1) low (2) (3) (4) (5) (6) (7) high

sensitivity sensitivity

Question 8. Species' sensitivity to pHe: 

(0) N/A (1) low (2) (3) (4) (5) (6) (7) high

sensitivity sensitivity

Question 9. Species' sensitivity to CO2

f: 

(0) N/A (1) low (2) (3) (4) (5) (6) (7) high

sensitivity sensitivity

Question 10. Species' reproductive strategy: (0) N/A (1) r-selection (2) (3) (4) (5) (6) (7) K-selection 

(can exploit (present as 

empty strong competitors

 niches/ in crowded niches/

reproduce invest heavily in 

quickly) fewer offspring)
107

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 7.3—Questions posed to participants in the process used to assess the sensitivity of wildlife species to climateaQuestion 11. Occupies the following sensitive habitat typesg

Coastal lowlands/marshes/ Perennial Shallow Vernal pools Ecotones Alpine/ Other estuaries streams wetlands/ or seasonal subalpine

shallow pools wetlands

a The number in parentheses before each answer choice represents the score that answer would produce for the calculation of the climate change sensitivity score. Sensitivity scores are on a scale of 0 to 100 and based on an additive function. In addition to the calculated sensitivity scores, after each question, each participant was asked to rate their level of confidence in the value that was collectively reached through this process, giving a measure of uncertainty to collective answers for each question. b Sensitivity to temperature is directly related to a species’ physiological ability to tolerate temperatures that are higher or lower than the range that it currently experiences. If a species can 

tolerate a wide range of temperatures, it would be deemed less sensitive.

c Sensitivity to precipitation should be based on the species’ ability to tolerate higher or lower levels of precipitation than that which it currently experiences. If a species can tolerate a great deal 

more or less precipitation than usual, they should be deemed less sensitive.

d Sensitivity to salinity refers to the species’ ability to tolerate either higher or lower levels of salinity than it currently experiences. The ability to tolerate a wide range of salinity indicates 

that the species is less sensitive.

e Sensitivity to pH refers to a species’ ability to tolerate either higher or lower pH than it currently experiences. (This is most applicable to aquatic organisms.) If a species can tolerate a wide 

range of pH, it should be deemed less sensitive.

f Sensitivity to carbon dioxide (CO2) refers to the ability of a species to tolerate greater or lesser amounts of CO2 than it currently experiences (this may be most important in plant species). 

If a species can tolerate a wide range of CO2 levels, it should be deemed less sensitive. g If the species occupies none of these habitats, then the score is 0. If the species occupies one or more of these habitats, then the score is 7.

options and action plans for wildlife habitat management. 

Jessica Halofsky (University of Washington) provided 

an overview of potential impacts of climate change on 

wildlife and vegetation on the Olympic Peninsula. Michael 

Case (University of Washington) presented results of the 

sensitivity assessment for selected wildlife species on the 

peninsula, and wildlife specialists Susan Piper (ONF) and 

Patti Happe (ONP) gave presentations on wildlife habitat 

management at ONF and at ONP, respectively. A discussion 

on adaption options for wildlife management with climate 

change followed. Part of the discussion involved review of 

suggested adaptation strategies for wildlife management 

and biodiversity conservation in a recent journal article 

(Mawdsley et al. 2009). Key points from the discussion are 

described below and in table 7.4. See box 7.1 for a general 

summary of projected effects of climate change on wildlife 

on the Olympic Peninsula and related adaptation strategies 

for wildlife and wildlife habitat management at ONF and 

ONP. 

Olympic Peninsula Wildlife Species Sensitivity to 

Climate Change

The wildlife species sensitivity assessment indicated that, 

in general, specialist species and species that use sensitive 

habitats will likely be more sensitive to climate change 

than more generalist species and species that use less 

sensitive habitats (fig. 7.8). Species that occupy sensitive 

habitats, such as the Olympic torrent salamander (headwater streams), Cascades frog and Van Dyke’s salamander 

(aquatic habitats), dog star skipper butterfly (meadows), 

Makah copper butterfly (wetlands), and the Olympic 

marmot (fig. 7.3), mountain goat, Clark’s nutcracker (fig. 

7.4), and gray-crowned rosy finch (high-elevation habitats), 

were generally ranked as highly sensitive to climate change. 

Similarly, specialist species in terms of habitat and diet, 

such as Clark’s nutcracker, northern spotted owl, graycrowned rosy finch, Van Dyke’s salamander, American 

marten, and northern flying squirrel, were ranked as highly 

sensitive to climate change. More generalist species, such 

as the barred owl, snowshoe hare (fig. 7.9), North American 

black bear, mountain beaver, and Roosevelt elk were not 

ranked as highly for sensitivity to climate change. 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Figure 7.9—Snowshoe hare does not change fur color seasonally 

on the Olympic Peninsula as it does in other regions. Snowshoe 

hare is a generalist and thus may not be as sensitive to climate 

change as other species on the Olympic Peninsula. (Photo by 

Betsy Howell, USDA Forest Service, Olympic National Forest.)

Figure 7.8—Modeled and subjective climate change sensitivity scores for selected species on the Olympic Peninsula. Modeled sensitivity scores were determined from experts’ answers to questions and calculated based on an additive function (see table 7.3). Subjective 

sensitivity scores were experts’ opinions on how sensitive a given species will be to climate change.

The sensitivity assessment process assisted in initially 

identifying species and groups of species that will likely 

be most sensitive to climate change on the peninsula. The 

process also led to useful discussion and deeper thinking 

about how individual and groups of species may be affected 

by climate change. However, the sensitivity assessment is 

still under development, and participants identified several 

limitations of the tool. For example, there was a large 

discrepancy between the modeled sensitivity and the subjective sensitivity scores for some species, likely because there 

are effects of climate change and other factors that make 

species sensitive to climate change that are not captured 

in the assessment. Alternatively, experts’ expectations for 

wildlife sensitivities to climate change are greater than the 

model suggests. In either case, the assessment process left a 

high level of uncertainty about the actual sensitivity of any 

of the species considered. Developers received critiques of 
109

Adapting to Climate Change at Olympic National Forest and Olympic National Park

Table 7.4—Projected climate change sensitivities, and associated adaptation strategies and actions for 

wildlife and habitat management at Olympic National Forest (ONF) and Olympic National Park (ONP)a

Current and expected sensitivities Adaptation strategies and actions

Limited connectivity of late-successional forests • Collaborate with neighbors about priority areas for treatments, 

and increase extent of protected areas.

Limited ability of species to respond to climate • Increase thinning treatments in young-growth forests that

change owing to current stressors, such as habitat promote late-successional forest conditions and improve habitat 

loss and fragmentation quality and suitability for some wildlife species at ONF.

• Focus thinning treatments (to promote late-successional 

conditions) around existing late-successional forests to increase 

landscape connectivity and increase wildlife habitat quality 

at ONF.

• Increase restoration treatments in, and protection of, headwater 

streams to increase late-successional habitat connectivity at ONF.

• Add a climate layer to ONF’s 10-year plan that shifts priorities 

for thinning treatments and road decommissioning and leads to 

increased habitat quality and connectivity.

Risk of large, high-severity fire • Determine how to jointly manage fire (ONF and ONP).

• Consider allowing fires to burn more frequently.

• Monitor postfire regeneration to determine what can be expected 

after large fires.

• Decrease stand densities and increase use of prescribed fire to 

lower wildfire severity.

Reduced late-successional habitat area and • Continue to create and protect legacy structures at ONF.

habitat quality • Increase density of legacy structures in younger forest near 

late-successional forest to increase habitat quality and 

connectivity at ONF.

• Continue to thin stands at ONF to promote tree vigor and produce 

future legacy structures.

• Continue to restore degraded sites.

Reduced habitat quality, particularly in riparian • Restore habitat in degraded headwater streams at ONF that are

areas and wetlands expected to retain adequate summer streamflow.

Increased spread of aquatic exotic plant species • Control spread of exotic species.

Loss of cold water refugia for cold-water adapted • Consider creating wetland habitats. 

amphibians

Change in wetland, bog, and fen distribution

Increased risk of species extinction, particularly • Consider inventory and monitoring opportunities to address

for endemics questions for species sensitive to climate change, including 

listed species.

• Conduct integrated surveys and monitoring for key species to 

obtain baseline information and determine when population 

changes are occurring.

• Reduce existing pressures on species from sources other than 

climate change. a

 Sensitivities are based on projected climate change effects on the Olympic Peninsula, including changing habitat distribution and quality with 

changing vegetation patterns, shifts in geographic ranges of wildlife species, shifts in ranges of competitor, forage, prey, and symbiotic species (and 

biotic interactions), changing species phenology, increased fire frequency, potential for increased insect and disease outbreaks, changing hydrology, 

and reduced summer streamflows.
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GENERAL TECHNICAL REPORT PNW-GTR-844

Box 7.1—Summary of projected climate change effects on wildlife on the Olympic Peninsula and 

related adaptation strategies for wildlife and wildlife habitat management at Olympic National 

Forest (ONP) and Olympic National Park (ONP).

• Climate change, in combination with other stressors to wildlife such as habitat loss and fragmentation, 

has the potential to greatly affect wildlife species and biodiversity on the Olympic Peninsula.

• Species will respond to both direct and indirect effects of climate change. For example, increasing temperatures 

and changing precipitation will have direct physiological effects on some species, such as amphibians. Other 

species will be affected mostly indirectly through:

o Climate-induced changes in phenology (timing of life history) relative to forage plants and invertebrate 

prey

o Shifts in geographic ranges and the density and ranges of competitor, forage, prey, and symbiotic species 

 (and subsequent changes in biotic interactions) in response to changing climate

o Effects from other stressors such as disturbance, insects, and disease

o Climate-induced changes in habitat characteristics and quality

• Some Olympic Peninsula species will likely respond to increasing temperature by shifting their ranges upward 

in elevation. High-elevation species will likely be particularly sensitive to warming temperatures and experience 

range contractions because contiguous, higher elevation habitat may not be available to colonize.

• It may also be more difficult for endemic and specialist species with strict habitat requirements or dependencies 

on specific forage species to find suitable habitat conditions under changing climate.

• Active management by restoration thinning in existing young-growth forest at ONF is a strategy that may help to 

ensure maintenance of enough forest with desired late-successional habitat characteristics (currently rare) across 

the landscape. Thinning to promote late-successional conditions at ONF may be most effective around existing 

late-successional forests to increase landscape connectivity and increase wildlife habitat quality.

• Protection and restoration of headwater streams and encouraging vigorous conifer growth could help to prevent 

increasing stream temperatures with climate change and increase habitat connectivity.

• At the stand scale, ONF can continue to increase wildlife habitat quality through creation and protection of 

legacy structures, including old-growth trees, snags, and large downed wood, as these legacy structures have 

disproportionate habitat value for a large number of species.

• Because many actions that could help increase wildlife species’ resilience to climate change will be most 

effective at large spatial scales and with consideration of landscape context, ONF and ONP will increase 

collaboration with neighbors to develop and increase the extent of a landscape strategy.

the assessment during the workshops and will consider the 

critiques in further refinement of the assessment tool and 

associated database. However, issues with the sensitivity 

assessment tool and database may stem from a fundamental 

lack of empirical data on wildlife species and their likely 

responses to changing climate. Additional empirical data 

and baseline assessments are needed to track changes in 

species’ response in the early phases of climate change. 

Such early assessments will be vital as we attempt to 

forecast long-term changes in response to climate change. 

Adaptation Strategies and Actions for Wildlife and 

Habitat Management at Olympic National Forest 

and Olympic National Park

Many actions that could help increase wildlife species’ 

resilience to climate change will be most effective at 

broad spatial scales (Millar et al. 2007), especially for 

management targeted at increasing habitat connectivity. 

Given the many landowners on the peninsula, increasing 

habitat quality and connectivity will require collaboration 

with neighbors about where to apply treatments to benefit 

wildlife habitat. Dialogue with the Washington Department 
111

Adapting to Climate Change at Olympic National Forest and Olympic National Park

of Fish and Wildlife, Washington Department of Natural 

Resources (a major landowner on the peninsula), and other 

federal agencies could help to develop and increase the 

extent of a landscape strategy. The ONF and ONP will also 

seek opportunities for collaboration with other peninsula 

landowners. 

Logging activities through the end of the 20th century 

left a scarcity of late-successional forest at ONF. Latesuccessional forests provide high-quality habitat for many 

species, including the northern spotted owl. Some latesuccessional forests may decline with climate change and 

be replaced by natural regeneration. Active management 

by thinning in existing young-growth forest at ONF is a 

strategy that may help to ensure maintenance of enough forest with desired habitat characteristics across the landscape. 

Thinning can reduce habitat quality and suitability for 

certain species that prefer dense forest conditions typical of 

the stem exclusion phase of forest succession (Hagar et al. 

1996, Hayes et al. 2003, Suzuki and Hayes 2003). However, 

thinning in structurally simple young-growth forests can 

also improve habitat quality and suitability for a variety 

of other species by promoting tree growth, species and 

structural diversity, and understory development (Carey and 

Wilson 2001, Hagar et al. 1996, Hayes et al. 2003, Suzuki 

and Hayes 2003). Young-growth thinning increases tree 

vigor by increasing availability of water, light, and nutrient 

resources; enhances tree species diversity by providing 

growing space for less competitive minor species; and provides growing space for understory vegetation to increase in 

abundance and diversity (Roberts and Harrington 2008). 

Thinning to promote late-successional conditions 

at ONF may be most effective adjacent to existing latesuccessional forests to increase landscape connectivity and 

increase wildlife habitat quality (the exception to this would 

be around known owl and murrelet nesting sites, where concern for short-term disturbance could outweigh long-term 

habitat improvement). Alternatively, thinning treatments 

could be focused in areas dominated by young forests. For 

example, young forests dominate the northwestern corner 

of ONF, which is the least connected to the park. Focusing 

treatments in that portion of the forest may have the greatest 

effect on habitat quality. 

Areas selected for thinning also need to be strategically 

located with the consideration of climate-altering disturbance processes and growing conditions. Some treatments 

may be a combination of habitat characteristic development 

and fire fuel reduction, depending on the location. Fuel 

reductions may be particularly important to high-value 

riparian areas, where habitat value would be susceptible to 

fire. 

Another way to potentially increase late-successional 

habitat connectivity is through restoration thinning treatments and protection of headwater stream areas at ONF, 

because forests that surround headwater streams are widespread and connected. Protection of headwater streams, and 

encouraging vigorous conifer growth, could help to prevent 

increasing stream temperatures with climate change and 

prevent sediment movement downstream. Management 

activities that promote forest resilience around non-fishbearing headwater streams could also improve habitat 

for amphibians, which are likely to be highly sensitive to 

climate change. For example, during thinning treatments, 

some trees could be dropped into streams to create instream 

structures that provide habitat and improve water holding 

capacity. 

Currently, ONF uses a 10-year strategic plan to direct 

locations of thinning and road decommissioning activities 

(among others). The strategic plan emphasizes restoring 

and connecting fragmented terrestrial and aquatic habitats. 

The plan does not currently consider potential effects of 

climate change, but modifying treatment prioritization 

could help to incorporate climate change in the plan. For 

example, thinning treatments could be prioritized around 

existing late-successional forest and around headwater 

streams to increase late-successional habitat connectivity. 

A geographic information system analysis could be used 

to identify gaps in desirable conditions and determine 

where treatments would be most effective. Also, habitat 

surveys could help to determine where the best corridors for 

movement exist on the peninsula, and treatments could be 

positioned accordingly. Wildlife could also be given greater 

consideration in prioritization of road decommissioning 

on the forest; roads that inhibit species movement could be 

prioritized for decommissioning. 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Another step for ONF and ONP is to determine how to 

jointly manage fire. The ONP will revise their fire plan in 

the near future and broaden the scope of the planning effort 

to include ONF. Allowing wildfires to burn more frequently 

at ONF and ONP may have some benefits, such as maintenance of alpine meadows, which will likely see increased 

tree encroachment with warming temperatures. Monitoring 

of recent burns and postfire regeneration could help determine if forage species are likely to regenerate after fire (e.g., 

Do important meadow species return after fire?). Management could also be tailored to decrease fire intensity. For 

example, decreasing stand density and increasing use of 

prescribed fire could help to decrease wildfire intensity, and 

firebreaks could be created to slow wildfire spread. These 

activities could be particularly useful in productive areas 

in the northeastern portion of the peninsula, where fire is 

more frequent and stands would likely respond to thinning 

through increased tree growth and vigor. 

At the stand scale, ONF could continue to increase 

wildlife habitat quality through creation and protection of 

legacy structures, including old-growth trees, snags, and 

large downed wood. Legacy structures have disproportionate habitat value for a large number of species. Although 

not a specific habitat type, these structures may mediate 

structural deficiencies in younger stands by providing for 

critical habitat needs. Old-growth trees have furrowed 

bark, cavities or basal hollows, large limbs, and defects that 

can provide nesting or roosting substrate, prey, or resting 

cover for species that might not otherwise be able to inhabit 

a younger stand. For example, long-legged bats, pygmy 

nuthatches, violet-green swallows, and Vaux’s swifts were 

documented reproducing in individual old-growth redwood 

trees with basal hollows or other cavities that were located 

in younger managed stands, and a variety of other bat and 

bird species used them for foraging or roosting (Mazurek 

and Zielinski 2004, Zielinski and Gellman 1999). Large 

standing hollow trees or fallen logs can provide hibernation 

dens for bears, natal and maternal dens for meso-predators 

such as the American marten and Pacific fisher, and cool, 

moist conditions for amphibians (such as Van Dyke’s 

salamander) and mollusks. Overall, snags and coarse wood 

are very important to a variety of wildlife because of the 

food or prey they provide, protection from the elements, or 

structures for rearing young. 

Olympic National Forest currently induces mortality 

of large trees for snag creation. This practice could be 

continued and possibly increased for further habitat quality 

improvement. Increasing density of legacy structures in 

younger forests may be particularly effective near latesuccessional forest to increase habitat quality and connectivity. Protection of existing legacy structures will also 

be important in providing critical habitat elements for a 

variety of species that may help them to respond adaptively 

to climate change. 

Although there is a need for legacy structure creation 

in the short term, there is also a need for high tree vigor for 

creation of future legacy structures. At ONF, stands could 

be thinned and trees left on site to elicit both a growth 

response and a positive effect on habitat quality. Thinning 

could also help forests to be more resilient to drought and 

disturbance with climate change.

Besides legacy structure protection and creation, 

other measures could be taken to further increase habitat 

quality at the stand scale. For example, creation of habitat 

structures, such as brush piles, could provide habitat for 

salamander species under increasing summer drought. 

Restoring currently degraded sites could also help to 

increase the area of high-quality habitat at ONF and ONP. 

Policy Considerations and Next Steps

Policy will be highly relevant to wildlife management at 

ONF and ONP with climate change. Both ONF and ONP 

currently focus resources on species that are sensitive, 

threatened, endangered, or iconic, but it is uncertain what 

will happen in the future when climate-related changes 

could lead to many more extinction possibilities. Because of 

the number of endemic species on the peninsula, there will 

be an opportunity for the forest and park to direct the discussion on what to do about many species at risk of extinction. The forest and park will keep up-to-date on the federal 

threatened and endangered list, as well as the Washington 

sensitive species list. Integrated surveys and monitoring can 

be conducted for key species to obtain baseline information 

and determine when population changes are occurring (e.g., 
113

Adapting to Climate Change at Olympic National Forest and Olympic National Park

the endemic Olympic marmot and amphibians in the high 

lakes areas). The forest and park will consider expanded 

data sharing and joint or expanded monitoring projects with 

common protocols, involving other adjacent landowners 

whenever possible. Specific recommendations for managing 

the effects of climate change can be developed for species 

for which a large amount of information already exists. 

Reducing existing pressures on species from sources 

other than climate change will also be important to protect 

TES species. The ONF and ONP will work to evaluate 

current activities to determine if stresses can be reduced 

for species that will be most impacted by climate change 

(e.g., focus on keeping streams cool for the Olympic torrent 

salamander, and increase coordination on exotic species 

control). 

In the future, depending on agency policies and partnerships, ONF and ONP may also consider assisted migration and captive breeding for species that may otherwise go 

extinct. It is possible that the peninsula will be a refuge for 

species from other parts of the Pacific Northwest over the 

long term. However, criteria and methods for conducting 

assisted migration as a strategy, as well as potential ecosystem impacts, are unclear.

Although ONF and ONP are mandated to protect TES 

species, there are currently policy limitations on the actions 

that can be taken to protect these species. Under current 

policies, management actions that would affect native 

species to protect or restore TES species must be undertaken through a careful planning process and in a way 

that will not produce unacceptable impacts on resources 

or natural processes. For ONP, policy guidance on when 

or whether to intervene in ecosystem processes in the face 

of climate change is limited. For example, the population 

of Olympic marmot (fig. 7.3), an endemic species to the 

peninsula, is declining on the peninsula owing in part 

to unsustainable levels of coyote predation (Griffin et al. 

2008), and warming temperatures may enhance coyote presence in the high-elevation marmot habitat. Potential options 

for coyote control are complicated under existing policies. 

Policy guidance regarding how or if to manage the situation 

is imprecise. Reintroduction of a top predator, the gray wolf, 

could decrease coyote numbers but would likely have other 

ecosystem impacts and raise controversy. Similarly, there 

are limitations to actions that can be taken to control the 

barred owl and its negative impact on the northern spotted 

owl. Other similar situations may arise in the future with 

species ranges that may shift in response to climate change. 

The Endangered Species Act (ESA 1973) guides 

agencies to consider the needs of individual species in their 

management activities, and conservation of individual species under the Endangered Species Act will likely continue 

for some time. In some cases, management for particular 

species whose presence is crucial to the maintenance of 

current ecosystem dynamics (e.g., top predators and major 

herbivores) may be required to maintain ecosystem function 

with changing climate. However, other efforts to maintain 

and restore ecosystem function will be important with the 

changes in forest species composition and disturbance that 

will likely occur with warming. With climate change, it may 

be particularly important to focus management on habitats, 

habitat structural components, and headwaters and cold 

water flows. Monitoring these habitats and habitat components will be particularly useful for detecting changes 

in habitat attributes and taking management action, when 

possible, to limit negative consequences for the species that 

use the habitats. 

To garner public support for policies and actions related 

to climate change, ONF and ONP may need to expand 

outreach to explain the reasoning behind policies and 

actions. The park and forest can increase interaction with 

local communities about how they are addressing climate 

change in management and how climate change may affect 

the public. Education about potential changes in wildlife 

may be especially necessary because, for example, black 

bear conflicts increase when there are berry crop failures, 

which may become more frequent with climate change.

Overall, current wildlife management at ONF and 

ONP is consistent with strategies and actions that would 

help to increase species and ecosystem resilience to climate 

change. For example, ONP currently manages for ecosystem 

function, and ONF focuses much of their management on 

restoration. However, there are ways, outlined here, that 
114

GENERAL TECHNICAL REPORT PNW-GTR-844

ONF and ONP could shift their strategies and foci to better 

address potential changes with warming temperatures. 

Acknowledgments

We thank the individuals who participated in the series of 

workshops that led to this chapter, including Keith Aubry, 

Brian Biswell, and Marty Raphael (Forest Service Pacific 

Northwest Research Station), Kim Mellen-McLean (Forest Service, Pacific Northwest Region), John Fleckenstein 

(State of Washington, Department of Natural Resources), 

Jim Michaels (U.S. Fish and Wildlife Service), and Aaron 

Wirsing (University of Washington). This chapter was 

improved by helpful reviews by Nicole Maggiulli, Marty 

Raphael, and Aaron Wirsing.

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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Chapter 8: Synthesis and Conclusions

Catherine Hawkins Hoffman, Kathy A. O’Halloran, Jessica E. Halofsky, and David L. Peterson1

1 Catherine Hawkins Hoffman is the Climate Change Adaptation Coordinator, National Park Service Natural Resource 

Program Center, 1201 Oakridge Dr., Fort Collins, CO 80525 (formerly Chief, Natural Resources Division, Olympic National Park, 

Port Angeles, WA); Kathy A. O’Halloran is the natural resources staff officer, U.S. Department of Agriculture, Forest Service, 

Olympic National Forest, 1835 Black Lake Blvd. SW, Olympia, WA 98512-5623; Jessica E. Halofsky is a research ecologist, 

University of Washington, College of the Environment, School of Forest Resources, Box 352100, Seattle, WA 98195-2100; David 

L. Peterson is a research biological scientist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, 

Pacific Wildland Fire Sciences Laboratory, 400 N 34th St., Suite 201, Seattle, WA 98103.

Utility of the Adaptation Planning Process

The Olympic Climate Change Case Study illustrated the 

utility of place-based vulnerability assessments and sciencemanagement workshops in facilitating climate change adaptation planning. We built on climate change education, and 

initial science-management discussions to develop specific 

and tangible ways for Olympic National Forest (ONF) and 

Olympic National Park (ONP) to incorporate climate change 

adaptation strategies into management. Development of 

science-based adaptation strategies was fostered by direct 

engagement of scientists and managers in the workshops. 

Presentations describing results of science-based vulnerability assessments helped to spur dialogue. The workshop 

format gave managers an open forum to brainstorm, express 

initial thoughts and ideas, and vet those ideas among peers. 

Careful facilitation of workshop discussions led to a productive dialogue (Schmoldt and Peterson 1991).

This study is an unprecedented example of collaboration by the U.S. Forest Service and National Park Service in 

preparation for climate change. The process used, involving 

sensitivity assessments, reviews of current management and 

management constraints, and adaptation workshops, can 

provide an example for other land and resource managers on 

how to initiate the climate change adaptation process. Many 

ideas from the case study could apply to other locations or 

agencies, and contribute to current planning processes and 

management programs. 

Lessons Learned

Where Is the Recipe? 

For climate change adaptation, there is no recipe, 

no road map, and yet no time to lose; science and 

management partners must tackle the climate change 

issue in a timely way, despite uncertainty.

It is challenging for agency managers to stay abreast of 

the rapidly evolving field of climate change science that contains as many questions as answers, further complicating 

decisionmaking. Consequently, the temptation is strong to 

wait for ready-made templates or fully developed, tried-andtrue examples of how to adapt to climate change. There are 

numerous efforts underway nationally and internationally to 

develop adaptation concepts and processes. Comparing and 

contrasting these to learn from other examples is critical to 

advancing climate change adaptation. However, this issue 

must be addressed as soon as possible to limit unwanted 

effects of changing climate.

Timing

The case study was timed to build on the momentum of 

a previous effort and was sufficiently long to enable the 

completion of a critical step in the adaptation process.

The case study was timed to build on the momentum 

of previous adaptation work on ONF and to take advantage 

of available funding for the effort. The case study was 

conducted over a 11⁄2 year period. Although this period was 

not sufficient to fully incorporate all resulting ideas into 

forest and park management, it was sufficient to complete a 

step in the adaptation process in which relevant science was 

presented and summarized, vulnerabilities were assessed, 

and initial adaptation strategies and options were developed. 

Scale and Participants

For all workshops, we encountered the challenge of 

balancing between soliciting input from many people 

and having a group small enough to facilitate discussion. 
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GENERAL TECHNICAL REPORT PNW-GTR-844

and to consider appropriate actions. However, there is much 

uncertainty associated with climate change, and an enormous amount of climate change information for managers 

to absorb. Consequently, the planning process should 

include sufficient time to establish a common foundation of 

information among participants. In other words, personnel 

need to be on the same page before they are able to take 

the next step in the adaptation process, which is to directly 

incorporate adaptation ideas into projects and planning. 

Establishing that degree of understanding among all personnel can be a time-consuming process. 

Structure for Results

Having more structure to the initial workshops, more 

prework, or having the workshops expand to several 

days may help in crafting more specific adaptation 

actions.

Initial discussions in group settings are often broad and 

general to explore different perspectives and solicit ideas. 

Additional steps may be required to distill and refine ideas 

and consider how these may affect management decisions 

and priorities. We dealt with this issue through iterative 

small group (three to four individuals) discussions after 

workshops. Additional structure may help in developing 

more specific adaptation options and would also enable 

more consistent partner participation, as several of the 

subsequent, small group discussions occurred opportunistically.

The Case for Splitting 

The more focused the study emphasis, the more specific 

the adaptation strategies that resulted. 

Bracketing specific disciplines (i.e., hydrology/roads, 

fish, vegetation, and wildlife) helped to move discussions 

from generic adaptation ideas, such as increasing ecosystem 

resilience, to more specific strategies that the agencies can 

more easily implement. In the vegetation focus area, ONF 

considered the idea of planting more drought-tolerant 

species to increase forest resilience, and determined that 

there are several drought-tolerant, native species that will 

likely do well in the future on the peninsula, including 

lodgepole pine and disease-resistant western white pine. 

The need for progress within a specific timeframe, and 

for continuity and commitment to the process over many 

months, in addition to the scheduling, logistics, and orchestration of a large-group planning process, were primary 

factors that led to limiting this initial effort to the forest 

and park. The structure of the workshops, which differed 

in size and composition depending on the topic, engaged 

program managers and resource specialists, and efficiently 

used the time of all participants while also ensuring ample 

time for discussion. To keep the meetings to a reasonable 

size, the majority of participants at most workshops were 

personnel of ONF and ONP (including regional-level staff), 

and invited scientists. The wildlife workshop included staff 

from the Washington Department of Natural Resources, the 

U.S. Geological Survey, and the U.S. Fish and Wildlife Service. The first fish workshop was larger by design because 

fish (particularly salmonids) are one of the widest ranging, 

multijurisdictional organisms inhabiting the peninsula. 

Over 100 representatives from other federal agencies, the 

state, tribes, universities, and nongovernmental organizations attended this workshop. A clear next step is to include 

these and other partners in a broader climate change adaptation effort on the peninsula. 

Scope

Framing the planning discussions around discrete topics 

allowed participants to discuss ideas within a group size 

that allowed all to contribute.

This was especially beneficial because some of the 

ideas and concepts were new, and participants ranged in 

knowledge of or engagement in climate change discussions. 

Participants were able to vet their ideas among peers and 

found it helpful to either validate or challenge their thinking. 

How to Deal With Copious New Information 

A common foundation and understanding of information needs to be developed among personnel to proceed 

in the adaptation process. This can be a time-consuming 

process.

The workshop format was useful to begin the conversation on how climate change may influence land management 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

In the hydrology and roads focus area, forest and park 

engineers discussed the idea of resizing culverts to accommodate increasing streamflow volumes, and ONF proposed 

two alternative methods for culvert sizing—by using a 

hydrologic model to predict future peak flows, and by using 

the last 30 years of record to estimate future peak flows 

instead of the entire period of record. Plans are underway to 

explore these approaches. 

These focus-area discussions produced tangible 

strategies. We are not certain that the engineers would have 

relished the Olympic marmot discussions, nor the wildlife 

biologists the culvert discussions. Some degree of splitting 

seemed advantageous.

The Case for Lumping—Synthesis Across 

Disciplines 

Integrating the concepts and plans from various 

program areas was an important step that should be 

expanded in future work.

After the various workshops were conducted, we held 

a synthesis session to compile ideas from the different 

focus areas, identify common approaches, and determine 

if any adaptation strategies and actions presented potential 

conflicts with one another. The synthesis workshop and 

subsequent small meetings gave resource specialists the 

opportunity to provide input on adaptation strategies 

developed in areas outside of their primary area of expertise. For example, the fish biologists could give input on 

adaptation strategies developed for vegetation management 

and identify any potential conflicts with fish resources. 

This synthesis of adaptation options for different focus 

areas helped refine the adaptation ideas and focus on key 

strategies that were common across focus areas (see themes 

section below). The strategies that were common across 

focus areas are most likely to be implemented, because 

these strategies are most likely to have the biggest impact. 

In future adaptation planning, this synthesis portion of the 

work could be expanded, with periodic integrated discussions (across focus topics) held at regular intervals throughout the planning process.

Making It Real—Incorporate Geospatial Planning 

The Olympic Climate Change Case Study process is 

an excellent first step as the agencies move forward in 

preparing for a changing climate, but scaling to local 

actions requires additional work.

To apply results from the workshops, more detailed 

and site-specific examples would assist managers and 

other landscape planning efforts. Ideally these adaptation 

concepts would have geospatial references. For example, the 

next iteration of planning for fish resources would include 

delineation of high-priority restoration sites. However, that 

level of effort was not possible within our funding and time 

limits. 

Dealing With Uncertainty

We used several approaches to work with or around 

uncertainty, including focusing on changes that have 

been observed in the past and with recent warming; 

focusing on similarities between different climate and 

impacts scenarios, and the most likely and plausible 

trends; using local knowledge of forest and park specialists to predict system response to climate change; and 

focusing on no-regrets strategies.

A key lesson learned about dealing with uncertainty 

is that the full range of future climate and climate change 

effect projections must be considered when developing 

adaptation strategies. We quickly realized it was impossible 

to know the best future projection for any particular area 

(e.g., hydrology and vegetation), so adaptation strategies 

must be robust. Adding scenario planning to the exercise 

would be a useful next step. However, we used several other 

approaches to work with or around uncertainty to develop 

tangible adaptation strategies. First, in assessing sensitivity to climate change in each focus area, we considered 

ecological changes that have been observed with climatic 

variability in the past or that have already been observed 

with recent warming. When assessing projected effects 

of climate change, we focused on similarities between 

the various future climate and effects scenarios, and the 

most likely trends. We used local knowledge of ONF and 

ONP staff and regional scientists to help predict species 
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GENERAL TECHNICAL REPORT PNW-GTR-844

that human-caused landscape changes or even recent 

climate change enabled its population expansion to the west 

coast of the United States (Kelly et al. 2003). Under current 

policies, biologists view the barred owl as an invader as 

opposed to a member of a new faunal assemblage. Climate 

change, like human structural development, is a humancaused modifier of habitats and ecosystems. As species 

move in response to habitat loss or gain caused by climate 

change, new management goals and a new definition for 

exotics will be needed.

Capacity 

The climate change adaptation process benefits from 

having an individual or individuals dedicated to facilitating the process and also requires focused time from 

staff specialists.

This case study project had the benefit of full-time 

assistance from a research ecologist associated with the 

University of Washington’s School of Forest Resources 

who organized and facilitated the workshops, invited and 

scheduled speakers, took notes, synthesized literature, 

provided presentations of projected climate change effects, 

and prepared draft manuscript chapters for the case study 

report. This effort was essential for developing sciencebased adaptation strategies with sufficient depth for clear 

application to agency management. 

In addition to managing the workload associated with 

organizing a planning process, focused time from staff specialists is essential. Adaptation or scenario planning added 

to existing workloads is challenging to implement. To fully 

develop robust, place-based adaptation strategies, either the 

responsibilities of staff specialists’ day jobs must be temporarily relieved, or a process established and funded much 

like watershed analysis conducted under the Northwest 

Forest Plan (USDA and USDI 1994) to develop adaptation 

strategies. Climate change could also be incorporated into 

other appropriate planning efforts. Appropriate facilitation 

and strong commitments by all parties are essential. Lack of 

funding or support may hinder progress, but in the face of 

potential effects of climate change, postponing discussions 

on adaptation may reduce options for managing potentially 

adverse conditions in some ecosystems.

and system response to changing climate on the Olympic 

Peninsula. Finally, in developing adaptation strategies, we 

always focused on no-regrets approaches, or strategies that 

will increase ecosystem function and resilience regardless 

of the exact nature of future climate. Additional work will 

be needed to build on these results, and to integrate with 

neighboring lands. 

Rethinking Management Goals

Climate change challenges current precepts and guidelines, and determining management goals within what 

may be entirely new ecosystems will be needed.

In the long term, yet still within planning horizons for 

both agencies, ecosystem changes and disturbances may 

occur more quickly in systems that have been relatively 

stable for hundreds or thousands of years. Determining 

management goals within what may be entirely new ecosystems will be needed. When once we might have observed 

or monitored, we may now need to undertake manipulative 

experiments that are different from any current management practices, particularly in the park. Goals that will be 

appropriate for fire management in environments modified 

by climate change are unclear. Similarly unclear are goals 

for wilderness management in potentially highly altered 

environments of the future. These and other questions 

indicate the limits of current understanding.

The case study exercise highlighted other situations 

that challenge our precepts and current guidelines. For 

example, although specialists may readily accept new 

concepts of ecosystem change, imagining how to address 

anticipated new conditions within current guidelines and 

definitions was sometimes a challenge. This was particularly evident at the wildlife workshop in which participants 

readily acknowledged that communities will be disrupted, 

that there will likely be different species assemblages in 

the future, and that managing for processes may be more 

important than managing for particular species. In this 

context, the question of whether the definition of exotic 

species will be altered with climate-induced changes in species distributions is, as yet, unanswered by ecologists and 

policymakers. For example, the barred owl arrived relatively 

recently on the peninsula and scientists have hypothesized 
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Raising Awareness

The workshops helped foster a cultural shift needed to 

incorporate climate change considerations into thoughts, 

plans, and actions for managers. This will be an ongoing, 

continually evolving process.

In some respects, at this early stage, it is less about 

developing the best adaptation plans and more about raising awareness, engaging a full range of participants, and 

enabling federal land managers to collectively think in new 

ways. 

Themes in Climate Change Adaptation 

Strategies at Olympic National Forest and 

Olympic National Park 

Several themes in adaptation strategies and actions emerged 

during the case study. In all four focus areas, contemplating the projected effects of climate change made the new 

management paradigm obvious—decisions can no longer 

assume a future that mirrors historical ecosystem conditions. Given the dynamic nature of climate and ecosystems, 

maintaining ecosystem function and biodiversity and 

increasing ecosystem resilience are often cited as suitable 

goals for adaptation in a changing climate (e.g., Baron et al. 

2008, Blate et al. 2009, Dale et al. 2001, Joyce et al. 2009, 

Millar et al. 2007, Spittlehouse and Stewart 2003). The case 

study identified numerous ways to maintain ecosystem 

function and biodiversity and increase resilience to climate 

change at ONF and ONP. However, the looming questions 

of determining conditions for considering assisted migration, or redefining exotics, remain for discussion across 

broader spatial scales.

Workshop participants frequently remarked on the 

importance of monitoring as a critical element in tracking 

ecosystem change, and in serving adaptive management 

efforts to determine effects of management actions. Monitoring, restoration, and protection were often proposed for 

the most climate-sensitive habitats on the peninsula, including headwater streams and high-elevation ecosystems. 

Assessment of current management activities revealed 

that management strategies at ONF and ONP are generally 

consistent with those that are likely to increase species and 

ecosystem resilience to climate change. The case study 

also helped identify new potential actions, and actions that 

could be increased or reprioritized, or both. For example, 

an adaptation strategy for both agencies is to plan for 

larger and additional culverts on roads. A new strategy for 

ONF, where managers currently conduct forest thinning to 

promote late-successional conditions, may be to alter the 

nature and increase the extent of thinning activities to further increase forest resilience to drought. Prioritization of 

thinning activities around existing late-successional forest 

could also help to increase habitat quality for some wildlife 

species. And although ONF does not currently place large 

wood in headwater channels to restore natural sediment 

routing, this will be considered as a way to help restore and 

protect headwater streams and the species that depend on 

them. These and other ideas will require more indepth and 

integrated analysis before implementation. 

Next Steps

Collaboration between land and resource management 

agencies in response to climate change is critical. The 

Olympic Climate Change Case Study illustrated the utility 

and success of agency collaboration in climate change 

adaptation planning. Although differences in mandates and 

management approaches exist between the forest and park, 

many ideas were developed about ways that ONF and ONP 

can work together to adapt to climate change.

Some adaptation ideas can be implemented right away, 

whereas others may be inappropriate until some of the projected effects of climate change are realized. Alternatively, 

small-scale experiments can be considered in the near 

term as a hedging strategy. Scenario planning to describe 

plausible futures, associated management strategies, and 

conditions that would trigger one decision over another, is 

a next logical step to build on this case study. Continual 

evaluation of the realized and projected effects of climate 

change will help determine appropriate triggers for specific 

actions. Future iterations of a process such as the one used 

in this case study will also likely lead to better informed 

adaptation actions by natural resource agencies. 

Agency policies may either help or hinder collaboration 

and the adaptation process in general. Except for actions 

proposed in small areas, or for species that have very 
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GENERAL TECHNICAL REPORT PNW-GTR-844

Joyce, L.A.; Blate, G.M.; Littell, J.S. [et al.]. 2009.

Managing for multiple resources under climate change. 

Environmental Management. 44: 1022–1032.

Kelly, E.G.; Forsman, E.D.; Anthony, R.G. 2003. Are 

barred owls replacing spotted owls? The Condor. 105: 

45–53.

Millar, C.I.; Stephenson, N.L.; Stephens, S.L. 2007.

Climate change and forests of the future: managing in 

the face of uncertainty. Ecological Applications. 

17: 2145–2151.

Schmoldt, D.L.; Peterson, D.L. 1991. Applying 

knowledge-based methods to design and implement an 

air quality workshop. Environmental Management. 

15: 623–634. 

Spittlehouse, D.L.; Stewart, R.B. 2003. Adaptation to 

climate change in forest management. BC Journal of 

Ecosystems and Management. 4: 1–11.

U.S. Department of Agriculture, Forest Service; 

U.S. Department of the Interior, Bureau of Land 

Management [USDA and USDI]. 1994. Record of 

decision for amendments to Forest Service and Bureau 

of Land Management planning documents within the 

range of the northern spotted owl [Place of publication 

unknown]. 74 p. [plus attachment A: standards and 

guidelines]. 

limited range, many adaptation strategies may fail unless 

managers of large landscapes concur on goals and objectives more broadly than at present. Although it is uncertain 

exactly how regulations, agency policies, or guidelines may 

change in the future, they may need to evolve to encourage greater agency collaboration in addressing climate 

change. Climate change adaptation is a process that requires 

continued awareness and attention by managers. Staying 

abreast of available information on potential climate change 

effects is essential to determine additional ways to incorporate climate change adaptation into management. This case 

study is a beginning; in the future, we plan to expand its 

scope and create additional partnerships that will improve 

the process and products from this work.

Acknowledgments

We thank Ellen Eberhardt for her helpful editing of the 

entire publication. We also thank Charisse Sydoriak, Karen 

Bennett, and Jill Dufour for their careful reviews of the 

report. Robert Norheim created the maps in this publication. 

Jeffrey Muehleck also helped develop the maps in chapters 

2 and 6.

Literature Cited

Baron, J.S.; Allen, C.D.; Fleishman, E. [et al.]. 2008.

National parks. In: Julius, S.H.; West, J.M., eds., and 

Baron, J.S.; Joyce, L.A.; Kareiva, P. [et al.], eds. Keller, 

B.D.; Palmer, M.A.; Peterson, C.H.; Scott, J.M., authors. 

Preliminary review of adaptation options for climatesensitive ecosystems and resources: a report by the U.S. 

Climate Change Science Program and the Subcommittee 

on Climate Change Research. Washington, DC: U.S. 

Environmental Protection Agency: 4–1 to 4–68.

Blate, G.M.; Joyce, L.A.; Julius, S. [et al.]. 2009. 

Adapting to climate change in United States national 

forests. Unasylva. 60: 57–62. 

Dale, V.H.; Joyce, L.A.; McNulty, S. [et al.]. 2001. 

Climate change and forest disturbances. Bioscience. 

51: 723–734.
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Common and Scientific Names

American kestrel Falco sparverius L.

American marten Martes americana Turton

American pika Ochotona princeps

 Richardson

American shad Alosa sapidissima Wilson

Bald eagle Haliaeetus leucocephalus

 L.

Balsam woolly adelgid Adelges picea Ratzeburg

Barred owl Strix varia Barton

Bass Micropterus spp.

Beargrass Xerophyllum tenax

 (Pursh) Nutt.

Bighorn sheep Ovis canadensis Shaw

Bigleaf maple Acer macrophyllum

Pursh

Bobcat Lynx rufus Schreber

Bracken fern Pteridium aquilinum (L.) 

 Kuhn

Bull trout Salvelinus confluentus

 Suckley

Bushy-tailed woodrat Neotoma cinerea Ord

Camas Camassia quamash

 (Pursh) Greene

Canada lynx Lynx canadensis Kerr

Cascades frog Rana cascadae Slater

Cattail Typha latifolia L.

Channel catfish Ictalurus punctatus

 Rafinesque

Chinook salmon Oncorhynchus 

 tshawytscha Wolbaum

Chum salmon Oncorhynchus keta

 Wolbaum

Clark’s nutcracker Nucifraga columbiana

Coho salmon Oncorhynchus kisutch

 Wolbaum

Columbia black-tailed deer Odocoileus hemionus 

 columbianus 

 (Richardson)

Cope’s giant salamander Dicamptodon copei

Coyote Canis latrans Say

Cutthroat trout Salmo clarki Richardson

Dog star skipper butterfly Polites sonora siris 

 (W.H. Edwards, 1881)

Douglas-fir Pseudotsuga menziesii

 (Mirb.) Franco

Douglas-fir beetle Dendroctonus 

 pseudotsugae Hopkins

Garter snake Thamnophis spp.

Giant chinquapin Chrysolepis chrysophylla

 (Douglas ex Hook.) 

 Hjelmqvist

Grand fir Abies grandis (Douglas 

 ex D. Don) Lindl.

Gray wolf Canis lupus L.

Gray-crowned rosy finch Leucosticte tephrocotis

Grizzly bear Ursus arctos horribilis

 Ord

Ground squirrel Spermophilus spp.

Huckleberries Vaccinium spp.

English Equivalents

When you know: Multiply by: To find:

Millimeters (mm) 0.039 Inches

Centimeters(cm) .394 Inches

Meters (m) 3.28 Feet

Kilometers (km) .621 Miles

Hectares (ha) 2.47 Acres

Square meters (m2) 10.76 Square feet (ft3)

Square kilometers (km2) .386 Square miles

Cubic meters per second (m3/sec) 35.3 Cubic feet per second (cfs)

Degrees Celsius 1.8 °C + 32 Degrees Fahrenheit
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GENERAL TECHNICAL REPORT PNW-GTR-844

Japanese knotweed Polygonum cuspidatum 

 Siebold & Zucc.

Keen’s myotis bat Myotis keenii (Merriam)

Little brown bat Myotis lucifugus

 LeConte

Lodgepole pine Pinus contorta Dougl. ex 

 Laud.

Long-legged bat Myotis evotis (H. Allen)

Long-toed salamander Ambystoma 

 macrodactylum 

 (Baird, 1889)

Makah copper butterfly Lycaina mariposa

Marbled murrelet Brachyramphus (Reakirt, 

 1866) marmoratus

 Gmelin

Mountain beaver Aplodontia rufa

 Rafinesque

Mountain goat Oreamnos americanus

 de Blainville

Mountain hemlock Tsuga mertensiana

 (Bong) Carr.

Mountain pine beetle Dendroctonus 

 ponderosae Hopkins

Nettle Urtica dioica L.

New Zealand mud snail Potamopyrgus 

 antipodarm J.E. Gray

North American black bear Ursus americanus Pallas

North American Porcupine Erethizondorsaturn (L.)

Northern alligator lizard Elgaria coerula

 Wiegmann

Northern flying squirrel Glaucomys sabrinus

 Shaw

Northern goshawk Accipiter gentilis L.

Northern spotted owl Strix occidentalis 

 caurina Merriam

Northwestern salamander Ambystoma gracile Baird

Olympic marmot Marmota olympus

 Merriam

Olympic mudminnow Novumbra hubbsi Schultz

Olympic pocket gopher Thomomys mazama 

 melanops Merriam, 

 1899

Olympic torrent salamander Rhyacotriton olympicus

 (Gaige, 1917)

Oregon white oak Quercus garryana 

 Douglas ex Hook.

Pacific chorus frog Pseudacris regilla Baird 

 & Girard 

Pacific fisher Martes pennanti 

 (Erxleben, 1777)

Pacific madrone Arbutus menziesii Pursh

Pacific silver fir Abies amabilis (Douglas 

 ex Louden) Douglas ex 

 Forbes

Pallid horned lark Otocoris alpestris 

 arcticola Orberholser

Perch Perca spp.

Pileated woodpecker Dryocopus pileatu L.

Pink salmon Oncorhynchus gorbuscha

 Wolbaum

Ponderosa pine Pinus ponderosa Dougl. 

 ex C. Laws.

Pygmy nuthatch Sitta pygmaea Vigors

Rainbow trout Oncorhynchus mykiss

 Wolbaum

Red alder Alnus rubra Bong.

Red fox Vulpes vulpes L.

Red osier dogwood Cornus sericea L.

Red-legged frog Rana aurora Baird & 

 Girard

Redwood Sequoia sempervirens

 (Lamb. ex D. Don) 

 Endl.

Roosevelt elk Cervus canadensis 

 roosevelti T

Salal Gaultheria shallon Pursh

Salmonberry Rubus spectabilis Pursh

Snowshoe hare Lepus americanus

 Erxleben

Sockeye salmon Oncorhynchus nerka

 Wolbaum

Steelhead Oncorhynchus mykiss

 Wolbaum

Subalpine fir Abies lasiocarpa (Hook.) 

 Nutt.

Tailed frog Ascaphus truei Stejneger

Taylor’s checkerspot butterfly Euphydryas editha 

 taylori (Edwards)

Townsend big-eared bat Plecotus townsendii 

 (Cooper, 1837)
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Van Dyke’s salamander Plethodon vandykei

 (Van Denburgh, 1906)

Vaux’s swift Chaetura vauxi

 (J.K.Townsend, 1839)

Violet-green swallow Tachycineta thalassina

 Swainson

Virginia Opossum Didelphis Virginiana 

 Kerr

Warty jumping slug Hemphillia glandulosa

 Bland & Binney

Western heather vole Phenacomys intermedius

 Merriam

Western hemlock Tsuga heterophylla (Raf.) 

 Sarg.

Western redcedar Thuja plicata Donn ex 

 D. Don.

Western toad Bufo boreas Baird & 

 Girard

Western white pine Pinus monticola Douglas 

 ex D. Don

White-tailed ptarmigan Lagopus leucura

 Richardson

Willow Salix spp. L.

Wolverine Gulo gulo L.

Yellow-bellied marmot Marmota flaviventris

 Audubon & Bachman

Zebra mussel Dreisenna polymorpha

 Pallas
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Adapting to Climate Change at Olympic National Forest and Olympic National Park

Glossary

Adaptation—(1) An adjustment in ecological, social, 

or economic systems in response to climate stimuli and 

their effects, which moderates harm or exploits beneficial 

opportunities; (2) a process, action, or outcome in a system 

(household, community, organization, sector, region, country) in order for the system to better cope with, manage, or 

adjust to some changing condition, stress, hazard, risk, or 

opportunity.

Adaptive capacity—The ability of a system to adjust 

to changes in climate (including climate variability and 

extremes) to moderate potential damages, to take advantage of opportunities, or to cope with the consequences.

Biodiversity—The sum of species, ecosystem, and genetic 

diversity Average conditions (mean and variability) in the 

atmosphere, ocean, and ice sheets and sea ice over a period 

of time, ranging from months to thousands or millions of 

years.

Climate change—Change in climate (in mean state or 

variability) over time. Climate change can occur as a result 

of changes in the Earth’s orbit around the sun, cyclical patterns in circulation of the oceans and atmosphere, cycles in 

the ocean-atmosphere system, or human-caused activities.

Climate envelope models—Statistical models that predict 

future species distribution based on the relationship 

between current species distribution and climate variables 

(and sometimes other variables).

Climate forcing—A mechanism that affects climate (e.g., 

changes in the composition of the Earth’s atmosphere 

through greenhouse gas emissions).

Dynamic global vegetation model—Model that is based 

on soil and climate information that simulate key physiological processes in plant communities to infer vegetation 

type over time.

Ecosystem—A system of interacting living organisms 

together with their physical environment. The boundaries of what could be called an ecosystem are somewhat 

arbitrary, depending on the focus of interest or study, and 

thus, the extent of an ecosystem may range from very 

small spatial scales to the entire Earth.

Ecosystem management—(1) Management that integrates 

scientific knowledge of ecological relationships within a 

complex sociopolitical and values framework toward the 

general goal of protecting native ecosystem integrity over 

the long term; (2) any land-management system that seeks 

to protect viable populations of all native species, perpetuate natural disturbance regimes on the regional scale, adopt 

a planning timeline of centuries, and allow human use at 

levels that do not result in long-term ecological degradation.

Ecosystem resilience—The amount of change or disturbance that can be absorbed by an ecosystem before the 

ecosystem is redefined by a different set of processes and 

structures (e.g., the ecosystem recovers from the disturbance without a major phase shift).

Ecosystem services—Ecological processes or functions 

that have value to individuals or society.

Exotic species—Also referred to as “alien,” “nonnative,” 

and “‘introduced” species. These terms refer to any species 

that is not native to a particular ecosystem. Nonnative species may or may not be invasive.

Exposure—The character, magnitude, and rate of climate 

change and variation to which a system is exposed.

Gap model—Model that simulates forest interactions and 

dynamics on a small, gap-sized patch of land (usually 0.02 

acre [0.01 hectare] and larger). Gap models can be used to 

project potential forest response to climate change.

Global climate models—Global climate models (GCMs) 

are coupled global climate models of the Earth’s atmosphere, oceans, sea ice, and terrestrial biosphere. These 

computationally intensive numerical models have been 

under development for many decades and are based on the 

integration of fluid dynamics, chemical, and sometimes biological equations. They spontaneously exhibit interannual 

and interdecadal oscillations like those observed in the real 

Earth system. They are run under different starting conditions and using different amounts of solar, volcanic, and 

greenhouse gas forcing of the atmospheric dynamics. Using 

this ensemble approach, various GCMs have successfully 

simulated the Earth’s climate over the past 1,000 years.
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GENERAL TECHNICAL REPORT PNW-GTR-844

Greenhouse gases—Gases that trap heat in the atmosphere. 

The main greenhouse gases in the Earth’s atmosphere are 

water vapor, carbon dioxide, methane, nitrous oxide, and 

ozone.

Invasive species—A species, usually exotic, with the potential to spread rapidly and cause economic or environmental 

harm.

Intergovernmental Panel on Climate Change (IPCC)—

A scientific intergovernmental body that evaluates the 

risks associated with human-caused climate change. The 

United Nations established the panel in 1988. The IPCC has 

published a series of special reports and periodic assessment 

reports (approximately every 5 years since 1990). 

Native species—A species that historically occurred or 

currently occurs in a given ecosystem and that has not been 

introduced through human activities. 

Phenology—The timing of an organism’s life history events 

(e.g., flowering in plants) that are cued by the organism’s 

environment.

Rain-dominant watershed—A watershed that receives 

most precipitation as rain. Climate change will likely have 

minimal impact on timing of streamflow in rain-dominant 

watersheds.

Restoration—Manipulation of the physical and biological 

environment in order to restore a desired ecological state or 

set of ecological processes.

Sensitivity—The degree to which a system will respond to 

a given stimulus.

Snowmelt-dominant watershed—A watershed that stores 

most winter precipitation in snowpack. This snowpack 

melts in the spring and early summer, resulting in peak 

streamflow in the late spring or early summer and lower 

streamflow during the winter months. Both increased 

winter rain (as opposed to snow) and shifts to earlier spring 

snowmelt with climate change will result in higher winter 

and spring streamflows and lower summer streamflows in 

snowmelt dominant watersheds.

Snow water equivalent—The depth of water in the snowpack, if the snowpack were melted. 

Special Report on Emissions Scenarios (SRES) emissions 

scenarios—The SRES was published by the Intergovernmental Panel on Climate Change for their third assessment 

report in 2001. The report gave details on potential future 

greenhouse gas emissions scenarios, which are dependent 

on current and future human activities, to drive global 

climate models. There are 40 emissions scenarios, all making different assumptions about technological and economic 

development. Of these 40, the three most commonly used 

scenarios are the B1 (relatively low future emissions), A1B 

(moderate future emissions), and A2 (relatively high future 

emissions). 

Stressor—An agent, condition, or other stimulus that can 

reduce the vigor or functionality of biological entities ranging from species to ecoystems.

Transient watershed—Watersheds located primarily 

at mid elevations that receive some snow and some rain. 

Streams and rivers draining transient watersheds often have 

one streamflow peak in fall or early winter owing to runoff 

generated by precipitation falling as rain, and another peak 

in late spring when the snowpack accumulated in midwinter 

melts. Both increased winter rain (as opposed to snow) and 

shifts to earlier spring snowmelt with climate change will 

result in higher winter and spring streamflows and lower 

summer streamflows in transient watersheds. 

Vulnerability—The degree to which a system is susceptible 

to, and unable to cope with, adverse effects of climate 

change, including climatic variability and extreme.
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