United States Department of Agriculture

Forest 

Service

Pacific Northwest 

Research Station

General Technical Report

PNW-GTR-892 September 

2014

Climate Change Vulnerability and 

Adaptation in the North Cascades 

Region, Washington
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Editors

Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle 

City Light, 700 5th Avenue, Seattle, WA 98124 (formerly, research biologist, U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Research Station, 

Pacific Wildland Fire Sciences Laboratory, Seattle, 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 Street, Suite 201, Seattle, WA 98103; and Regina M. Rochefort is a science 

advisor, U.S. Department of the Interior, National Park Service, North Cascades 

National Park Complex, 2105 State Route 20, Sedro-Woolley, WA 98284. 

Cover photo by Victor Mesny
Climate Change Vulnerability 

and Adaptation in the North 

Cascades Region, Washington

Crystal L. Raymond, David L. Peterson, and Regina M. Rochefort

Editors

U.S. Department of Agriculture, Forest Service

Pacific Northwest Research Station

Portland, Oregon

General Technical Report, PNW-GTR-892

September 2014
Abstract

Raymond, Crystal L.; Peterson, David L.; Rochefort, Regina M., eds. 2014.

Climate change vulnerability and adaptation in the North Cascades region, 

Washington. Gen. Tech. Rep. PNW-GTR-892. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 279 p. 

The North Cascadia Adaptation Partnership (NCAP) is a science-management 

partnership consisting of the U.S. Department of Agriculture Forest Service Mount 

Baker-Snoqualmie and Okanogan-Wenatchee National Forests and Pacific Northwest Research Station; North Cascades National Park Complex; Mount Rainier 

National Park; and University of Washington Climate Impacts Group. These 

organizations worked with numerous stakeholders over 2 years to identify climate 

change issues relevant to resource management in the North Cascades and to find 

solutions that will facilitate the transition of the diverse ecosystems of this region 

into a warmer climate. The NCAP provided education, conducted a climate change 

vulnerability assessment, and developed adaptation options for federal agencies that 

manage 2.4 million hectares in north-central Washington.

In the Pacific Northwest, the current warming trend is expected to continue, 

with average warming of 2.1 °C by the 2040s and 3.8 °C by the 2080s; precipitation 

may vary slightly, but the magnitude and direction are uncertain. This warming 

will have far-reaching effects on aquatic and terrestrial ecosystems. Hydrologic systems will be especially vulnerable as North Cascades watersheds become increasingly rain dominated, rather than snow dominated, resulting in more autumn/winter 

flooding, higher peak flows, and lower summer flows. This will greatly affect the 

extensive road network in the North Cascades (longer than 16 000 km), making it 

difficult to maintain access for recreational users and resource managers. It will 

also greatly reduce suitable fish habitat, especially as stream temperatures increase 

above critical thresholds. In forest ecosystems, higher temperatures will increase 

stress and lower the growth and productivity of lower elevation tree species on 

both the western and eastern sides of the Cascade crest, although growth of highelevation tree species is expected to increase. Distribution and abundance of plant 

species may change over the long term, and increased disturbance (wildfire, insects, 

and invasive species) will cause rapid changes in ecosystem structure and function 

across broad landscapes, especially on the east side. This in turn will alter habitat 

for a wide range of animal species by potentially reducing connectivity and latesuccessional forest structure.

Coping with and adapting to the effects of an altered climate will become 

increasingly difficult after the mid-21st century, although adaptation strategies 
and tactics are available to ease the transition to a warmer climate. For roads and 

infrastructure, tactics for increasing resistance and resilience to higher peak flows 

include installing hardened stream crossings, stabilizing streambanks, designing culverts for projected peak flows, and upgrading bridges and increasing their 

height. For fisheries, tactics for increasing resilience of salmon to altered hydrology 

and higher stream temperature include restoring stream and floodplain complexity, reducing road density near streams, increasing forest cover to retain snow 

and decrease snow melt, and identifying and protecting cold-water refugia. For 

vegetation, tactics for increasing resilience to higher temperature and increased 

disturbance include accelerating development of late-successional forest conditions 

by reducing density and diversifying forest structure, managing for future range of 

variability in structure and species, including invasive species prevention strategies 

in all projects, and monitoring changes in tree distribution and establishment at tree 

line. For wildlife, tactics for increasing resilience to altered habitat include increasing diversity of age classes and restoring a patch mosaic, increasing fuel reduction 

treatments in dry forests, using conservation easements to maintain habitat connectivity, and removing exotic fish species to protect amphibian populations.

The NCAP facilitated the largest climate change adaptation effort on federal 

lands to date by including many participants from other organizations to promote 

an all-lands approach to addressing climate change. It achieved specific elements 

of national climate change strategies for the U.S. Forest Service and National Park 

Service, providing a scientific foundation for resource management and planning 

in the North Cascades region. Rapid implementation of adaptation in sustainable 

resource management will enhance the potential for North Cascades ecosystems to 

maintain long-term functionality in future decades.

Keywords: Access, adaptation, climate change, fire, forest ecosystems, fisheries, hydrology, North Cascade Range, North Cascadia Adaptation Partnership, 

roads, science-management partnership, vegetation, wildlife.
Contents

1 Chapter 1: Introduction

 Crystal L. Raymond, David L. Peterson, and Regina M. Rochefort

1 Climate Change Responses of the Forest Service and National 

Park Service 

3 Science-Management Partnerships

5 The North Cascadia Adaptation Partnership Process

8 All-Lands Approach to Climate Change Adaptation

10 Literature Cited

15 Chapter 2: Ecological, Biogeographical, and Historical Context of the 

North Cascade Range

 Kailey Marcinkowski, Crystal L. Raymond, and Lee K. Cerveny

16 Ecological Setting

17 Cultural History of the North Cascades

18 Geography, History, and Management

18 Mount Baker-Snoqualmie National Forest

19 Okanogan-Wenatchee National Forest

20 Mount Rainier National Park

20 North Cascades National Park Complex

22 Literature Cited

25 Chapter 3: Climate and Climate Change in the North Cascade Range

 Jeremy S. Littell and Crystal L. Raymond

25	 Climate of the Pacific Northwest

26	 Historical Climate Observations and Trends in the Pacific Northwest

30	 Future Climate in the Pacific Northwest

30 Models, Methods, and Data Used for Climate Projections

33 Projections of Temperature and Precipitation for the Pacific Northwest

40 Uncertainty in Future Climate Projections

41	 Acknowledgments

41 Literature Cited

45 Chapter 4: Climate Change, Hydrology, and Access in the North 

Cascade Range

 Ronda L. Strauch, Crystal L. Raymond, and Alan F. Hamlet

45 Introduction

48 The Current Context for Access in the North Cascades 

48 Current Development and Access Needs
50 Road and Trail Types and Conditions

51 Climate Change Effects Relevant to Access

51 Changing Climate in the Pacific Northwest

53 Climate Change Effects on Flooding and Extreme Low Flows

59 Climate Change Effects on Snow Cover

59 Effects of Changing Soil Moisture and Landslides

64 Sensitive Traits of Roads and Trails in the North Cascades

65 Aging Infrastructure

66 Design and Use Considerations

66 Location and Land Use

67 Maintenance and Management of Roads and Trails

68 Current and Short-Term Climate Exposures to Access 

in the North Cascades

72 Emerging or Intensifying Exposure in the Short Term

73 Emerging or Intensifying Exposure in the Medium and Long Term

79 Infrastructure and Travel Management in the North Cascades

79 Road and Trail Operations and Maintenance

81 Planning and Projects

83 Adapting Access Management in a Changing Climate

84	 Adaptation Options for Higher Peak Flows and Flood Risk

84 Road and Culvert Design and Maintenance

89 Facilities, Structures, and Cultural Resources

92 Trail Maintenance and Design

94 Adaptation Options for Higher Soil Saturation and Landslide Risk

94 Road and Facility Maintenance and Design

94 Trail Maintenance and Design

97 Adaptation Options for Visitor Use Patterns and Public Safety

100 Adaptation Options for Dry-Season Water Availability and Use

102	 Acknowledgments

102 Literature Cited

113 Chapter 5: Climate Change and Vegetation in the North Cascade Range 

 Jeremy S. Littell, Crystal L. Raymond, Regina M. Rochefort, and 

Stephen L. Klein 

113 Introduction

115 Current Vegetation in the North Cascades
117 Projected Changes in Regional Climate Relevant to Vegetation

120 Physical Mechanisms for Climatic Effects on Forest Vegetation

123 Climate Change Effects on Biodiversity and Vegetation Distribution

123 Projected Changes in Vegetation Biomes

126 Projected Changes in Climatic Suitability for Tree Species

128 Changes in Distribution of Rare Plant Species

128 Climate Change Effects on Ecological Disturbances

128 Insects

131 Fire Regimes

135 Forest Pathogens

136 Invasive Species

137 Disturbance Interactions

138 Vegetation Management Objectives

139 Mount Baker-Snoqualmie and Okanogan-Wenatchee National Forests

140 North Cascades and Mount Rainier National Parks

141 Vegetation Management Practices

141 Silviculture and Forest Restoration

142 Fire and Hazardous Fuel Management

143 Hazard Tree Management

143 Plant Ecology Programs

144 Invasive Species Management

146 Inventory and Monitoring

146 Adapting Vegetation Management in a Changing Climate

151 Adaptation Options for Managing Ecological Disturbances

156 Adaptation Options for Managing Floods, Wind, and Hazard Trees

159 Adaptation Options for Invasive Species Management

163 Adaptation Options for Managing Alpine and Subalpine Ecosystems

164 Acknowledgments

164 Literature Cited

177 Chapter 6: Climate Change, Wildlife, and Wildlife Habitat in the North 

Cascade Range

 Joshua J. Lawler, Crystal L. Raymond, Maureen E. Ryan, Michael J. Case, 

and Regina M. Rochefort

177 Introduction

178 Vulnerability Assessment for Wildlife and Habitat
180 Effects of Climate Change on Wildlife Species

181 Physiological Effects

182 Phenological Effects

183 Distributional Shifts

184 Interspecific Interactions

185 Interactions With Other Stressors

187 Effects of Climate Change on Wildlife Habitats

187 Alpine and Subalpine Zones

188 Meadows

188 Forests

189 Wetlands

191 Riparian Systems

191 Sensitivity of Selected Wildlife Species to Climate Change

204 Wildlife Management in National Forests and National Parks 

in the North Cascades

204 Planning and Regulation

206 Management of Wildlife Species in the North Cascades

208 Management of Wildlife Habitat in the North Cascades

209 Monitoring Wildlife and Habitat

210 Adapting Management of Wildlife and Wildlife Habitat in 

a Changing Climate

211 Adaptation Options for Low-Elevation Maritime Forests on the Western 

Slopes of the Cascade Range

213 Adaptation Options for East-Side Fire-Adapted Forest Habitat and 

Associated Species

216 Adaptation Options for Riparian Forest Habitat and Associated Species

218 Adaptation Options for Wetland Habitats and Associated Species

222 Adaptation Options for Alpine and Subalpine Habitats and Associated Species

224	 Acknowledgments

224 Literature Cited

235 Chapter 7: Climate Change, Fish, and Fish Habitat in the North 

Cascade Range

 Nathan J. Mantua and Crystal L. Raymond

235 Introduction

236	 Effects of Climate Change on Streamsflows
237 Projected Changes in Streamflow Timing

237 Projected Changes in Stream Temperature

240 Effects of Climate Change on Fish and Fish Habitat

242 Stream Temperature

246 Peak Streamflow

247 Summer Low Streamflow

247 Management of Fish and Fish Habitat in the North Cascades

248 Management of Fish and Fish Habitat on the Mount Baker-Snoqualmie and 

Okanogan-Wenatchee National Forests

250 Management of Fish and Fish Habitat at Mount Rainier and North Cascades 

National Parks

251 Adapting Fish Management to Climate Change in the North Cascades

252 Adaptation Options to Reduce Effects of High Peak Streamflows

256 Adaptation Options to Reduce Effects of Lower Low Streamflows

258 Adaptation Options to Reduce Effects of Warmer Stream Temperatures

263 Adaptation Options to Reduce Effects of Sedimentation

265	 Acknowledgments

265 Literature Cited

271 Chapter 8: Conclusions

 Crystal L. Raymond, David L. Peterson, and Regina M. Rochefort

271 Relevance to Agency Climate Change Response Strategies

272 Communication, Education, and Organizational Capacity

273 Partnerships and Engagement

273 Assessing Vulnerability and Adaptation

274 Science and Monitoring

275 Mitigation and Sustainable Operations

275 Next Steps

275 Engagement and Partnerships

275 Vulnerability Assessment and Adaptation Planning

276 Implementing Adaptation Strategies and Tactics

276 A Vision for Adaptation as a Dynamic Process

278	 Acknowledgments

278 Literature Cited
1

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

The U.S. Department of Agriculture Forest Service (USDA FS) Pacific Northwest 

Research Station and the U.S. Department of the Interior National Park Service 

(NPS) initiated the North Cascadia Adaptation Partnership (NCAP) in 2010. The 

NCAP is a science-management collaboration with the goals of increasing climate 

change awareness, assessing vulnerability, and developing science-based adaptation strategies to reduce adverse effects of climate change and ease the transition to 

new climate states and conditions. Developed in response to the proactive climate 

change strategies of the Forest Service (USDA FS 2008) and NPS (USDI NPS 

2010), the partnership brings together USDA FS scientists, University of Washington scientists, and both USDA FS and NPS resource managers.

Adaptation is defined by the Intergovernmental Panel on Climate Change 

(IPCC) as “initiatives and measures to reduce the vulnerability of natural and 

human systems against actual or expected climate change effects.” Mitigation is 

defined as “implementing policies to reduce greenhouse gas emissions and enhance 

sinks” (IPCC 2007). Mitigation is critical to reducing atmospheric levels of carbon 

dioxide (CO2

) and thus changes in the climate system. However, adaptation will 

still be necessary despite the extent and success of mitigation because of the slow 

response of the climate system to greenhouse gases that have already been emitted. 

Even if humans stop emitting greenhouse gases today, global temperature would 

continue to rise because of the response time required for the Earth to equilibrate to 

new levels of greenhouse gases in the atmosphere (Solomon et al. 2007). 

Climate Change Responses of the Forest Service and 

National Park Service 

Both the USDA FS and NPS have highlighted climate change as an agency priority 

and issued direction to administrative units for responding to climate change 

(USDA FS 2008, USDI NPS 2010). In 2010, the USDA FS provided specific 

direction to the National Forest System in the form of the National Roadmap for 

1 Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle City 

Light, 700 5th Avenue, Seattle, WA 98124 (formerly biological scientist, U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire 

Sciences Laboratory, Seattle, 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 Street, Suite 201, Seattle, WA 98103; 

and Regina M. Rochefort is a science advisor, U.S. Department of the Interior, National 

Park Service, North Cascades National Park Complex, 2105 State Route 20, Sedro-Woolley, 

WA 98284.

Chapter 1: Introduction

Crystal L. Raymond, David L. Peterson, and Regina M. Rochefort1
2

general technical report pnw-gtr-892

Responding to Climate Change (USDA FS 2010a) and the Performance Scorecard 

for Implementing the Forest Service Climate Change Strategy (USDA FS 2010b). 

The goal of the USDA FS climate change strategy is to “ensure our national forests 

and private working lands are conserved and made more resilient to climate change, 

while enhancing our water resources” (USDA FS 2010b). The performance scorecard outlines four elements for achieving this goal: (1) increasing organizational 

capacity; (2) partnerships, engagement, and education; (3) adaptation; and (4) 

mitigation and sustainable consumption. Progress toward accomplishing elements 

of the scorecard must be reported annually by each national forest and grassland, 

and all units are expected to accomplish these elements by 2015. National forests in 

the USDA FS Pacific Northwest Region must also complete climate change action 

plans that indicate how they will comply with the scorecard elements by 2015. 

Similarly, the NPS released the Climate Change Response Strategy in 2010 to 

provide direction for addressing climate change (USDI NPS 2010). This strategy 

describes goals and objections associated with four components of an integrated 

approach: science, mitigation, adaptation, and communication. For the science component, the agency is directed to conduct scientific research, in coordination with 

partners, that will assess climate change trends and vulnerability and provide the 

scientific basis for adaptation, mitigation, and communication. Mitigation efforts 

focus on reducing the NPS carbon emissions and enhancing carbon sequestration. 

Adaptation includes developing capacity within the agency to assess climate change 

scenarios and risks and implementing actions to better manage natural and cultural 

resources and infrastructure in a changing climate. The strategy also requires the 

NPS to take advantage of the agency’s history and capacity for interpretation by 

communicating climate change effects among park staff and to the public. The 

similarity in scope and direction of the two climate change response strategies 

facilitates coordination between the NPS and USDA FS. 

The NCAP built on several existing efforts to address climate change and put 

these efforts into a broader regional context by connecting resource managers from 

different agencies who are working to address climate change. The NPS launched 

the Climate Friendly Parks (CFP) program in 2002, which is part of the Green 

Parks Plan (NPS 2012). This plan sets goals for reducing greenhouse gas emissions through sustainable operations and is an integral part of the NPS Climate 

Change Response Strategy. In 2009, North Cascades National Park Complex and 

Mount Rainier National Park held workshops and became members of the CFP 

program. Following the workshops, each park conducted a baseline analysis of 

greenhouse gas emissions and adopted a climate action plan. The climate action 
3

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

plans outline targets and actions for reducing greenhouse gas emissions, efforts to 

increase education about climate change among staff and visitors, and priorities for 

developing adaptation strategies that increase the resilience of natural and cultural 

resources. The NCAP expands on these efforts by increasing education of park staff 

and expanding adaptation strategies. Although park managers began the process of 

adaptation planning through the CFP program, CFP efforts focused primarily on 

mitigation, whereas NCAP focused on adaptation, making the efforts complementary parts of a larger strategy for addressing climate change at the parks. 

The Okanogan-Wenatchee National Forest (OWNF), in collaboration with 

Colville National Forest, initiated a focus group to increase climate change awareness among forest staff and develop strategies to adapt resources and management 

practices to climate change. Scientists and managers presented current climate 

science and engaged in facilitated discussions of resource vulnerabilities and opportunities to enable natural resources to adapt to climate change (Gaines et al. 2012). 

The focus group identified several adaptation strategies for increasing the resilience 

of natural, social, and economic systems to climate change. Based on the results of 

this workshop, resource managers considered climate change in the development of 

the OWNF Forest Restoration Strategy (USDA FS 2012b) and the 2011 Land and 

Resource Management Plan (USDA FS 2011) revision process. The focus group 

emphasized that to make adaptation successful, the OWNF needed to increase 

climate change awareness among employees, collaborate between scientists and 

resource managers, and plan across jurisdictional boundaries. The NCAP is the 

next step in expanding employee education, extending the scope of the adaptation 

planning effort, and increasing partnerships with scientists and other resource 

management agencies.

Science-Management Partnerships 

Previous case studies have demonstrated the success of science-management 

partnerships for increasing climate change awareness among resource managers 

and adaptation planning on federal lands. The Olympic and Tahoe National Forests 

initiated the first science-management partnerships for developing adaptation 

options for individual national forests (Littell et al. 2012). The WestWide Climate 

Initiative (USDA FS 2007) expanded these initial efforts to develop science management partnerships by establishing three case studies in the Western United 

States, two of which included national parks adjacent to national forests. The 

Olympic climate change case study assessed resource vulnerabilities and developed adaptation options for Olympic National Park and Olympic National Forest 

on the Olympic Peninsula in Washington state (Halofsky et al. 2011). Three land 
4

general technical report pnw-gtr-892

management units in California—Tahoe National Forest, Inyo National Forest, and 

Devils Postpile National Monument—held climate change education workshops and 

developed the Climate Project Screening Tool to incorporate adaptation into project 

planning (Morelli et al. 2012). The Shoshone National Forest in northern Wyoming 

synthesized past climate, future climate projections, and potential effects of climate 

change on the multiple ecosystems within the forest (Rice et al. 2012). In the largest 

effort to date in the Eastern United States, the Chequamegon-Nicolet National 

Forest in northern Wisconsin conducted a vulnerability assessment for natural 

resources (Swanston et al. 2011) and developed adaptation options in collaboration 

with stakeholders (Swanston and Janowiak 2012). 

Peterson et al. (2011) synthesized the processes, products, and techniques used 

for these case studies and other climate change efforts on national forests in a 

guidebook for developing adaptation options for national forests. The guidebook 

outlines four key steps to facilitate adaption in national forests, and these steps are 

equally relevant for national parks: (1) become aware of basic climate change science and integrate that understanding with knowledge of local conditions and issues 

(review), (2) evaluate sensitivity of natural resources to climate change (rank), (3) 

develop and implement options for adapting resources to climate change (resolve), 

and (4) monitor the effectiveness of on-the-ground management (observe) and 

adjust as needed. The NCAP is an example of the principles and practices outlined 

in the guidebook and implemented as a place-based demonstration.

Figure 1.1—Project area for the North Cascadia Adaptation Partnership. The Partnership includes 

two national forests and two national parks for a total land area of 2.4 million ha. 
5

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

The North Cascadia Adaptation Partnership Process

The NCAP expands the methods of the previous case studies to a larger, more 

ecologically and geographically complex area and extends the approach of 

science-management partnerships to a broader range of stakeholders. It focuses on 

vulnerability assessment and adaptation planning for Mount Baker-Snoqualmie 

National Forest, Okanogan-Wenatchee National Forest, North Cascades National 

Park Complex, and Mount Rainier National Park, a total land area of 2.4 million ha 

in Washington (fig 1.1). Although these four administrative units form the core of 

NCAP, the partnership includes other local, state, and federal resource management 

agencies, and nongovernmental organizations in the region (fig. 1.2). The NCAP 

focuses on assessing vulnerability and developing adaptation options to reduce 

vulnerability. The NCAP process was conducted in four steps: (1) increase climate 

change awareness among NPS and USDA FS staff and partners; (2) assess vulnerability of natural and cultural resources and infrastructure; (3) develop adaptation 

options that the parks, forests, and their partners could potentially implement; and 

(4) build a continuing partnership of scientists and resource managers engaged in 

climate change issues in the region.

Educational workshops on climate change, one for each national forest and 

national park, initiated the NCAP process. Scientists from resource agencies and 

academic institutions presented the latest scientific information on projected 

changes in climate and the effects of these changes on natural resources. Workshops were attended by USDA FS and NPS employees from all sectors of the 

workforce, providing an opportunity for resource managers to engage in a dialogue 

with climate change scientists, voice current and future management challenges, 

and develop a common understanding of how climate change may affect natural 

resources. 

Building on the educational component, the NCAP assessed the vulnerability 

of natural and cultural resources and infrastructure and developed options for 

adapting resources and management to a changing climate. This was accomplished 

through a series of four 2-day workshops focused on specific resource sectors: 

hydrology and access, vegetation and ecological disturbance, wildlife, and fisheries. 

These resource sectors were selected based on their importance in the region and 

current management concerns and challenges. These resources are similar to the 

resources that were the focus of the Olympic climate change case study (Halofsky 

et al. 2011), but differed in two ways, reflecting differences in the disturbance ecology and predominant uses of public lands in the NCAP region. The national forests 

and national parks in the NCAP emphasized concerns about changes in ecological 
6

general technical report pnw-gtr-892

Figure 1.2—The national forests and national parks that comprise the core of the North Cascadia Adaptation Partnership (NCAP) 

area are surrounded by several other municipal, state, federal, private, and tribal ownerships. The partnership includes many of 

these land and resource management agencies in an effort to use an “all lands” approach in discussions and plans for climate change 

adaptation. 

disturbances, primarily fire and insects, and challenges associated with maintaining access for recreation users. For each resource sector workshop, scientists and 

resource specialists presented information on climate change effects and current 

management practices. Presentations were followed by facilitated dialogue to 

identify key sensitivities and adaptation options. 

To assess vulnerability, we consulted with experts and reviewed scientific 

literature on exposure to and potential effects of climate change on the four 

resource sectors. Vulnerability assessments typically involve exposure, sensitivity, 
7

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

and adaptive capacity (Parry et al. 2007), where exposure is the degree to which 

the system is exposed to changes in climate, sensitivity is an inherent quality of the 

system that indicates the degree to which it could be affected by climate change, 

and adaptive capacity is the ability of a system to respond and adjust to the exogenous influence of climate. Vulnerability assessments can be both qualitative and 

quantitative and focus on whole systems or individual species or resources (Glick 

et al. 2011). Several tools and databases are available for systematically assessing 

sensitivity (e.g., Lawler and Case 2010) and vulnerability of species (e.g., Potter and 

Crane 2010). For the NCAP, we used expert knowledge and best available science 

to assess vulnerability, with the exception of evaluating the sensitivity of several 

wildlife species of concern. To the greatest extent possible, we focused on effects 

and projections specific to the NCAP region and used the finest scale projections 

that are scientifically valid (Littell et al. 2011). Adaptive capacity can include the 

ability of species and ecosystems to respond to climate change, but also the extent 

to which organizations can accommodate changes in management practices necessary to adapt to climate change. To assess adaptive capacity, we reviewed current 

USDA FS and NPS management objectives and practices for each sector to determine opportunities and barriers for adapting to climate change. 

After identifying key vulnerabilities for each sector, we used facilitated discussions among scientists and resource managers during the workshop to identify 

potential adaptation options. Abundant literature is available on general principles 

for adapting resource management practices (Baron et al. 2009, Joyce et al. 2009, 

Millar et al. 2007), but literature on adaptation is mostly conceptual (Heller and 

Zavaleta 2009). This is partially because it is difficult to scientifically test the 

efficacy of management actions for adapting to climate change, but also because 

few efforts have connected the adaptation concepts with specific resources, places, 

and people. By working collaboratively with scientists and resource managers 

and focusing on a specific region, the goal of NCAP was to go beyond general 

concepts to identify specific actions that could be implemented into projects and 

plans (Peterson et al. 2011, Swanston and Janowiak 2012). For each resource sector 

workshop, participants identified strategies (general approaches) and tactics (onthe-ground actions) for adapting resources and management practices to climate 

change. Participants also identified barriers and opportunities for implementing 

these strategies and tactics into current projects, management plans, partnerships, 

regulations, or policies. Participants generally focused on adaptation options that 

could be implemented given current scientific understanding of climate change 

effects, but they also identified research and monitoring that would benefit future 

efforts to assess vulnerability and adapt management practices. Facilitators 

Vulnerability 

assessments can be 

both qualitative and 

quantitative and focus 

on whole systems or 

individual species or 

resources.
8

general technical report pnw-gtr-892

captured information generated during the workshops with a set of spreadsheets 

adapted from Swanston and Janowiak (2012). Initial results from the workshops 

were augmented with a review of the literature and continued dialogue with NPS 

and USDA FS resource specialists. The following report contains one chapter for 

each of the four resource sectors with a review of climate change effects, sensitivities, and current management practices (collectively the vulnerability assessment) 

and results of the adaptation planning discussions. 

Resource managers can use this report in several ways. First, the synthesis of 

projected changes in climate and hydrology in the North Cascades and potential 

effects on access, infrastructure, vegetation, wildlife, and fish is a state-of-science 

reference for addressing climate change in planning documents and projects. The 

report is not a comprehensive synthesis of all literature on climate change effects 

in the region, but it emphasizes the biggest challenges for these resource sectors. 

The four resource sectors on which this report focuses were chosen based on their 

importance in the region and at the request of forest and park managers. Second, 

resource managers can draw from the adaptation options presented in this report as 

they begin to implement actions in response to changes in climate and hydrology. 

We expect that over time, and as needs and funding align, that appropriate adaptation options will be incorporated into plans and programs of the parks, forests, and 

possibly other agencies. Adaptation planning is a gradual and iterative process. 

Implementation may happen at critical times in the planning process, such as when 

managers revise USDA FS land and resource management plans or NPS general 

management plans, or after the occurrence of extreme events (e.g., floods) or 

ecological disturbances. We focus on adaptation options for the USDA FS and NPS 

units that are the core of the partnership, but this report provides information that 

can be used by other resource management agencies in the partnership. Furthermore, the NCAP process can be emulated by national forests, national parks, and 

other organizations in the Pacific Northwest and beyond.

All-Lands Approach to Climate Change Adaptation

The USDA FS and NPS climate change strategies identify the need to build partnerships and work across jurisdictional boundaries when planning for adaptation. 

This concept of responding to the challenge of climate change with an “all-lands” 

approach is frequently mentioned, but a process for doing so is rarely defined. 

Unique in its effort to implement an all-lands approach to adaptation for a specific 

region, the NCAP is an inclusive partnership of multiple agencies and organizations 
9

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

with an interest in managing natural resources in a changing climate. In addition to 

representatives from the four NCAP forests and parks, several other agencies and 

organizations participated in the resource sector workshops and are identified in 

each chapter. This type of partnership enables a coordinated and complementary 

approach to adaptation that crosses jurisdictional boundaries. NCAP also provides 

a venue for agencies to learn from the practices of others so that the most effective 

adaptation strategies can be identified. 

The U.S. Department of the Interior Fish and Wildlife Service (USFWS) and 

the Washington Department of Ecology, both NCAP collaborators, have similar 

climate change response strategies to those of the USDA FS and NPS. Adaptation 

strategies, such as promoting resilience and resistance, mitigation options like 

carbon neutrality, and climate change engagement are the core goals of the USFWS 

Strategic Plan for Responding to Accelerating Climate Change (USFWS 2010). The 

Washington Department of Ecology Integrated Climate Response Strategy (Adelsman and Ekrem 2012), which applies to state agencies including the Department 

of Natural Resources and the Department of Fish and Wildlife, addresses effects, 

vulnerabilities, and adaptation strategies for different sectors (e.g., human health, 

water resources, and species habitats). The main goals are to improve scientific 

knowledge, engage in partnerships and collaborations, expand sustainability and 

resiliency efforts, and use integrated approaches to climate change management.

These climate change strategies differ among agencies but have many similarities. Risks and vulnerabilities resulting from climate change and gaps in scientific 

knowledge and policy need to be assessed. Adaptation is a focus of each of the 

strategic plans, with most centering attention on creating resilience in human and 

natural systems. Communicating climate change information and engaging employees, partners, and the general public in productive discussions is also an integral 

part of successfully responding to climate change. The need for partnerships and 

collaborations on climate change issues is also identified in all the plans. Sharing 

climate change information, vulnerability assessments, and adaptation strategies 

across administrative boundaries will contribute to the success of climate change 

responses in the North Cascades.
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Literature Cited

Adelsman, H.; Ekrem, J. 2012. Preparing for a changing climate: Washington 

state’s integrated climate response strategy. Pub. 12-01-004. Olympia, WA: 

Washington Department of Ecology. 207 p.

Baron, J.S.; Gunderson, L.; Allen, C.D. [et al.]. 2009. Options for national parks 

and reserves for adapting to climate change. Environmental Management. 44: 

1033–1042.

Gaines, W.L.; Peterson, D.W.; Thomas, C.A.; Harrod, R.J. 2012. Adaptations to 

climate change: Colville and Okanogan-Wenatchee National Forests. Gen. Tech. 

Rep. PNW-GTR-862. Portland, OR: U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Research Station. 34 p.

Glick, P.; Stein, B.A.; Edelson, N.A., eds. 2011. Scanning the conservation 

horizon: a guide to climate change vulnerability assessment. Washington, DC: 

National Wildlife Federation. 176 p.

Halofsky, J.E.; Peterson, D.L.; O’Halloran, K.A.; Hoffman, C.H. 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.

Heller, N.E.; Zavaleta, E.S. 2009. Biodiversity management in the face of 

climate change: a review of 22 years of recommendations. Biological 

Conservation. 142: 14–32.

Intergovernmental Panel on Climate Change [IPCC]. 2007. Summary for 

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

Climate change 2007: impacts, adaptation and vulnerability: a contribution of 

working group II to the fourth assessment report of the Intergovernmental Panel 

on Climate Change. Cambridge, United Kingdom: Cambridge University Press: 

7–22.

Joyce, L.A.; Blate, G.M.; McNulty, S.G. 2009. Managing for multiple resources under climate change: national forests. Environmental Management. 

44: 1022–1032.

Lawler, J.; Case, M. 2010. Climate change sensitivity database. [Database]. 

http://climatechangesensitivity.org. (28 August 2012). 
11

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Littell, J.S.; Elsner, M.M.; Mauger, G.S. [et al.]. 2011. Regional climate and 

hydrologic change in the northern U.S. Rockies and Pacific Northwest: internally 

consistent projections of future climate for resource management. Preliminary 

project report, USFS JVA 09-JV-11015600-039. Seattle, WA: University of 

Washington, Center for Science in the Earth System, Joint Institute for the Study 

of the Atmosphere and Ocean, Climate Impacts Group. http://cses.washington.

edu/picea/USFS/pub/Littell_etal_2010/Littell_etal._2011_Regional_Climatic_

And_Hydrologic_Change_USFS_USFWS_JVA_17Apr11.pdf. (15 April 2013).

Littell, J.S.; Peterson, D.L.; Millar, C.I.; O’Halloran, K.A. 2012. U.S. national 

forests adapt to climate change through science-management partnerships. 

Climatic Change. 110: 269–296. 

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.

Morelli, T.L.; Yeh, S.; Smith, N.M. [et al.]. 2012. Climate project screening tool: 

an aid for climate change adaptation. Res. Pap. PSW-RP-263. Albany, CA: U.S. 

Department of Agriculture, Forest Service, Pacific Southwest Research Station. 

29 p. 

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al.]. 2011. Responding to climate 

change in national forests: a guidebook for developing adaptation options. Gen. 

Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 109 p.

Potter, K.M.; Crane, B.S. 2010. Forest tree genetic risk assessment system: a tool 

for conservation decision-making in changing times. Version 1.2. http://www.

forestthreats.org/current-projects/project-summaries/genetic-risk-assessmentsystem. (28 August 2012).

Rice, J.; Tredennick, A.; Joyce, L.A. 2012. Climate change on the Shoshone 

National Forest, Wyoming: a synthesis of past climate, climate projections, and 

ecosystem implications. Gen. Tech. Rep. RMRS-GTR-274. Fort Collins, CO: 

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research 

Station. 60 p.

Solomon, S.; Qin, D.; Manning, M. [et al.], eds. 2007. Climate change 2007: the 

physical science basis. Contribution of working group I to the fourth assessment 

report of the Intergovernmental Panel on Climate Change. Cambridge, United 

Kingdom: Cambridge University Press. 996 p. 
12

general technical report pnw-gtr-892

Swanston, C.; Janowiak, M.; Iverson, L. [et al.]. 2011. Ecosystem vulnerability 

assessment and synthesis: a report from the climate change response framework 

project in northern Wisconsin. Gen. Tech. Rep. NRS-GTR-82. Newtown Square, 

PA: U.S. Department of Agriculture, Forest Service, Northern Research Station. 

142 p.

Swanston, C.W.; Janowiak, M.K., eds. 2012. Forest adaptation resources: climate 

change tools and approaches for land managers. Gen. Tech. Rep. NRS-GTR-87. 

Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern 

Research Station. 108 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2007. Westwide 

Climate Initiative: a research management partnership. http://www.fs.fed.us/psw/

topics/climate_change/pdf/Apr07hill_westsideCI.pdf. (28 August 2012).

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-framework-climatechange-1-0.pdf. (28 August 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010a. National 

roadmap for responding to climate change. http://www.fs.fed.us/climatechange/ 

pdf/roadmap.pdf. (28 August 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010b. A 

performance scorecard for implementing the Forest Service climate change 

strategy. http://www.fs.fed.us/climatechange/pdf/performance_scorecard_final. 

pdf. (28 August 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2011. Proposed 

action for forest plan revision, Okanogan-Wenatchee National Forest. Portland, 

OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station. 89 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012. The 

Okanogan-Wenatchee National Forest restoration strategy: adaptive ecosystem 

management to restore landscape resiliency. 2012 Version. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Region. 119 p.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

U.S. Department of the Interior, Fish and Wildlife Service [USFWS]. 2010.

Rising to the urgent challenge: strategic plan for responding to accelerating 

climate change. http://www.fws.gov/home/climatechange/pdf/CCStrategicPlan.

pdf. (28 August 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2010.

National Park Service climate change response strategy. Fort Collins, CO: 

National Park Service, Climate Change Response Program. 28 p. http://www.nps.

gov/orgs/ccrp/upload/NPS_CCRS.pdf. (28 August 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2012.

Green parks plan: advancing our mission through sustainable operations. http://

www.nps.gov/greenparksplan/downloads/NPS_2012_Green_Parks_Plan.pdf.

(28 August 2012).
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15

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

The North Cascadia Adaptation Partnership (NCAP) includes Mount Baker-Snoqualmie National Forest (MBSNF), Okanogan-Wenatchee National Forest (OWNF), 

North Cascades National Park Complex (NOCA), and Mount Rainier National Park 

(MORA), which occupy 2.4 million ha in the North Cascade Range in Washington 

state (referred to hereafter as the North Cascades). The area is climatologically and 

ecologically diverse, and each administrative unit has a different cultural history, 

policy history, legislative mandate, and management objectives. Because the NCAP 

assessed vulnerability to climate change and developed adaptation options for the 

North Cascades region as a whole, participants recognized differences in ecology 

and management objectives, leading to different priorities and adaptation strategies.

Despite differences among the four units, the North Cascades region is united 

by similarities in climate, ecology, resource use, and management objectives. The 

abundant snowfall, glaciated volcanoes, and high elevation of the region create a 

common ecological setting in which glaciers, alpine, and subalpine zones strongly 

influence ecological processes. Abundant large, glacial-fed rivers throughout the 

region provide critical habitat for cold-water fish and also serve as an important 

resource for hydropower and water for nearby urban communities. The proximity of 

the four units to the Seattle-Tacoma metropolitan area creates a common emphasis 

on managing for high public visitation and recreation, yet the steep terrain and 

rugged topography of the region limit access. Protection and conservation of latesuccessional forest habitat for wildlife species is a common objective for all national 

forests and national parks. Furthermore, Congressional wilderness designations 

for large portions of the national forests have increased the similarity between U.S. 

Department of Agriculture, Forest Service (USDA FS) and National Park Service 

(NPS) management. Current management objectives are built on a long tradition 

of dependence on the abundant natural resources of the region that extends back 

centuries, including the resource dependence of local Native American tribes. 

1 Kailey Marcinkowski is a research scientist, Michigan Technological University, School 

of Forest Resources and Environmental Science, 1400 Townsend Drive, Houghton, MI 

49931; Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle 

City Light, 700 5th Avenue, Seattle, WA 98124 (formerly a research biologist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific Wildland 

Fire Sciences Laboratory, Seattle, WA 98103); and Lee K. Cerveny is a research social 

scientist, U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station, Pacific Wildland Fire Sciences Laboratory, 400 N 34th Street, Suite 201, Seattle, 

WA 98103.

Chapter 2: Ecological, Biogeographical, and Historical 

Context of the North Cascade Range

Kailey Marcinkowski, Crystal L. Raymond, and Lee K. Cerveny1
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This common ecological, social, and historical context formed the basis of joint 

discussions on vulnerability to climate change and enabled the NCAP to identify 

common adaptation strategies that are relevant to the region as whole. It will continue to be important to recognize differences in agency mandates and management 

objectives, but developing regional adaptation strategies, as was undertaken by the 

NCAP, is the first step toward implementing an “all lands” approach to adaptation. 

Ecological Setting 

Elevations in the North Cascades extend from 185 m to 4392 m (the peak of Mount 

Rainier). Diverse geomorphic processes shaped the landscape, resulting in rugged 

topography and steep elevation gradients with corresponding gradients in temperature and precipitation (Franklin et al. 1988). The North Cascades has two distinct 

climatic divisions. On the west side of the Cascade Range, a temperate, maritime 

climate dominates, and annual precipitation ranges from 100 cm to more than 250 

cm. On the east side of the Cascade Range, the climate is more continental, and 

annual precipitation is as high as 130 cm near the Cascade crest and as low as 25 

cm near the eastern edge of OWNF. Mean annual temperature is similar for both 

sides of the Cascade Range, but temperature on the east side is more seasonally 

variable, with larger differences between annual and seasonal highs and lows. Snow 

accumulates as early as October and can reach depths greater than 7 m above 1500 

m elevation, often persisting into late summer. Mount Baker, located in MBSNF, 

holds the U.S. seasonal snowfall record of nearly 29 m of snow measured during the 

1998–99 season. Mount Rainier was the previous record holder for 28.5 m of snow 

during the winter of 1971–72 (National Climate Extremes Committee 2012).

In the North Cascades, elevation and climatic gradients create different combinations of temperature, moisture, and disturbance regimes, giving rise to many 

different ecosystems (Franklin et al. 1988). Vegetation associations include dry 

coniferous forests, temperate coniferous rain forests, subalpine forests and meadows, riparian forests, and treeless alpine. Western hemlock (Tsuga heterophylla

[Raf.] Sarg.), Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco), and western redcedar (Thuja plicata Donn ex D. Don), dominate low-elevation, west-side forests. 

Douglas-fir, ponderosa pine (Pinus ponderosa var. ponderosa Douglas ex P. 

Lawson & C. Lawson), grand fir (Abies grandis [Douglas ex D. Don] Lindl.), and 

western larch (Larix occidentalis Nutt.) dominate low-elevation east-side forests, 

and lodgepole pine (P. contorta var. latifolia Engelm. ex S. Watson) is common 

throughout mid-elevation east-side forests. Vegetation transitions from dry conifer 

forest to shrub-steppe and grassland toward the eastern edge of OWNF. Hardwood 

species such as red alder (Alnus rubra Bong.), bigleaf maple (Acer macrophyllum

Mount Baker holds the 

U.S. seasonal snowfall 

record of nearly 29 m 

of snow.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Pursh), and vine maple (A. circinatum Pursh) are common in riparian forests on the 

west side, and quaking aspen (Populus tremuloides Michx.) is found in riparian and 

high-elevation forests on the east side. Subalpine forests are dominated by mountain 

hemlock (Tsuga mertensiana [Bong.] Carrière), Pacific silver fir (Abies amabilis

Douglas ex J. Forbes), and subalpine fir (A. lasiocarpa [Hook.] Nutt.) on the west 

side and by subalpine fir, Engelmann spruce (Picea engelmannii Parry ex Engelm.), 

and subalpine larch (L. lyallii Parl.) on the east side. The North Cascades supports a 

high diversity of native plant species; NOCA alone contains 1,630 vascular species, 

the most of any park in the NPS. 

Cultural History of the North Cascades

Interactions between native peoples and their environments are an important 

part of the cultural history of the North Cascades, which supported many Native 

American tribes: the Skagit, Nooksack, Sauk-Suiattle, Okanogan, Methow, Chelan, 

Wenatchee, Salish, Nisqually, Puyallup, Muckleshoot, Squaxin Island, Yakama, 

Cowlitz, and Colville. Many of these tribes have relationships with the parks and 

forests that are part of the NCAP, and they work collaboratively to protect and 

manage the natural resources and cultural heritage of the area. Tribal partners were 

actively involved in the NCAP resource-sector workshops and provided expertise, 

local knowledge, and input to the adaptation planning process. 

Traditional uses of the land include hunting for mountain goat (Oreamnos 

americanus [de Blainville]), elk (Cervus elaphus L.), black-tailed deer (Odocoileus 

hemionus columbianus [Rafinesque]), mule deer (O. hemionus [Rafinesque]) hoary 

marmot (Marmota caligata [Eschscholtz]), black bear (Ursus americanus Pallas) 

(and formerly grizzly bear [U. arctos L.]), and many bird species, and foraging 

for a wide range of berries, roots, and mushrooms. Western redcedar and Alaska 

cedar (Callitropsis nootkatensis [D. Don] D.P. Little) trees were stripped of bark for 

clothing, baskets, mats, and containers (Burtchard 2003). Salmon was a main food 

staple for many tribes, so waterways were an important aspect of native life and 

provided access to trade routes. Trade paths were also established over land, and 

water and land routes opened up trade between inland and coastal tribes (Mount 

Baker Foothills Economic Development Association 2004).

The tribes of the North Cascades had various lifestyles. Some, like the Nooksack and Skagit, settled in permanent villages along rivers, but others lived in 

camps that moved depending on the season. Dart and arrow points, lithic debris, 

and other evidence of hunting and residential sites have been found throughout 

the region (Mierendorf 2004). Hundreds of archaeological sites, including rock 

shelters between 300 and 1,000 years old, indicate a long history of land use by 
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native peoples in the North Cascades (Burtchard 2003). Pictographs on the cliffs 

surrounding Lake Chelan were drawn by the Chelan tribe, and their creation is part 

of a tribal legend. Legends also surround the formations of Mount Rainier, Mount 

Baker, and several large rivers. 

Following European discovery of Puget Sound and the North Cascades, settlers explored the foothills and rivers, especially trappers engaged in the fur trade. 

Mining ventures were established throughout the area, and many small settlements 

became mining boom towns with a large influx of prospectors. The 1858 Fraser 

River gold rush brought nearly 10,000 of these prospectors into the foothills surrounding Mount Baker, and claims to ore deposits still exist today (Thompson 

1970). The large trees and extensive forest area of the region became an economic 

draw for logging operations in the 1870s, mostly in the lowlands along rivers. 

Railroads reached the Pacific Northwest in the 1890s, and settlements in the area 

began to expand. Toward the end of the 19th century, the area was first used for 

recreational purposes, such as mountaineering, and people began to take a greater 

interest in preserving the natural resources of the North Cascades.

Geography, History, and Management

Mount Baker-Snoqualmie National Forest

Mount Baker-Snoqualmie National Forest occupies 698 000 ha, extending 225 km 

on the western side of the Cascade Range from the Canadian border to Snoqualmie 

Pass and south of MORA. Nine wilderness areas, four of which are shared with 

the OWNF, comprise 48 percent of the MBSNF area. Among active volcanoes in 

the contiguous United States, Mount Baker (3286 m) is the fourth highest and most 

northern. There are 13 glaciers on its slopes. Several large rivers run through the 

MBSNF, including the Sauk, Suiattle, and Cascade Rivers, which are part of the 

Skagit River system.

The lands that make up MBSNF have a long history of preservation. Some of 

the forest area was reserved as part of Pacific Forest Reserve lands in 1893, and 

in 1908 it was converted to Snoqualmie National Forest (south), and Washington 

National Forest (north), the latter being renamed Mount Baker National Forest 

in 1924. After the dissolution of Mount Rainier National Forest, the Snoqualmie 

National Forest expanded, incorporating four ranger districts into its boundaries. 

When NOCA was formed, it was excised from Mount Baker National Forest. Mount 

Baker and Snoqualmie National Forests merged in 1973. 

Many areas have been established as wilderness since establishment of current 

MBSNF boundaries (Washington State Wilderness Act of 1984). Wilderness designations influence management for timber and wildlife habitat. More than 200 km 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

of river and shoreline have been designated as the Skagit Wild and Scenic River 

System to protect the flow, water quality, and recreation values of the river (Wild 

and Scenic Rivers Act 1968). The Skagit Wild and Scenic River System is taken 

into account when managing for recreation, hydroelectric power, flood control, 

species populations, and restoration along shorelines. 

The MBSNF manages for a broad range of recreational activities. Viewing 

natural features and wildlife, hiking, viewing wildlife, relaxing, and driving for 

pleasure are the top five recreational activities in MBSNF, and nearly 60 percent of 

visitors to the forest hike on established trails. Recreational use has increased from 

1,372,000 in 2005 to 1,995,000 in 2010, making MBSNF one of the most visited 

national forests in the United States. Beyond recreation, MBSNF also manages timber, fire, and sensitive species. These activities are designed to protect, maintain, 

and enhance the natural resources of the forest. The Wilderness Act (1964), Wild 

and Scenic Rivers Act (1968), National Environmental Policy Act (1969), Clean 

Air Act (1970, 1977), and Endangered Species Act (1973), all regulate management 

activities at MBSNF.

Okanogan-Wenatchee National Forest

The Okanogan-Wenatchee National Forest comprises more than 1.6 million ha 

on the eastern side of the Cascades from the Canadian border to south of Mount 

Rainier. The crest of the Cascade Range is the western border of OWNF, and 

the Okanogan Highlands are the eastern border. Eight wilderness areas, some of 

which are shared with MBSNF, cover about 40 percent of the land. Waterways are 

an important part of OWNF, which borders the Columbia River and the Yakima 

River valley. Cle Elum Lake, Kachess Lake, Keechelus Lake, Rimrock Lake, Lake 

Wenatchee, and Lake Chelan are all large lakes inside OWNF borders, and the 

Methow, Twisp, and Entiat Rivers flow through the forest.

The eastern slopes of the Cascade Range and the area surrounding Lake Chelan 

have been a popular recreation destination since the early 1900s. The need to set 

aside lands for preservation was recognized early, and the Wenatchee and Chelan 

National Forests were established separately in 1908. The Okanogan National Forest 

was established in 1911 and was incorporated into Chelan National Forest several 

years later. Chelan National Forest boundaries were kept the same, but the area 

was renamed Okanogan in 1955. Several wilderness areas were established in these 

national forests over the years, reserving land inside forest boundaries and adding 

land to expand the boundaries. The forests were combined in 2000 and the name 

was subsequently changed to Okanogan-Wenatchee National Forest. Management 

of the OWNF follows similar legislation as MBSNF, with additional emphasis on 
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fire and timber. Recreational usage of OWNF has decreased from 1,752,000 visitors 

in 2005 to 1,368,000 in 2010. Recreation activities include hiking, scenic driving, 

skiing, hunting, fishing, gathering forest products, and camping. 

Mount Rainier National Park

Mount Rainier National Park is located on the west side of the Cascade Range, 

about 100 km southeast of the Seattle-Tacoma area. The park is 96 000 ha, of which 

97 percent is designated as wilderness. Several historical areas within the park 

(about 1 percent) are designated as a National Historic Landmark District. The main 

attraction of the park is Mount Rainier, the largest peak in Washington state. Mount 

Rainier is an active volcano with the largest single-peak glacier system in the 

Pacific Northwest. An abundance of archaeological sites in the park are evidence 

of a long history of human use in this area.

Lands set aside for the Pacific Forest Reserve in 1893 were combined with land 

reclaimed from railroads to create the park in 1899, making it the fifth national park 

in the United States. The first national park to be patrolled solely by rangers (Catton 1996), it was the site of mining operations and fire suppression during its first 

decade of existence. When the NPS was established in 1916 (NPS 1916), MORA 

expanded operations, adding engineers, landscape architects, naturalists, and an 

educated ranger force. As the automobile became more popular and better roads 

and trails were built into the park, the number of visitors increased, especially for 

single day trips. The influx of visitors to the park resulted in MORA becoming the 

first national park, in 1928, to develop a master plan for development of roads and 

visitor and administration services (Catton 1996). Recreational activities in MORA 

include climbing, hiking, backpacking, camping, scenic drives, and wildlife and 

wildflower viewing, and visitation is gradually declining. There were 1,301,103 

visitors in 2001, decreasing to 1,038,229 in 2011. During that time, backcountry 

campers decreased from 64,362 to 39,907.

North Cascades National Park Complex

North Cascades National Park Complex spans 279 000 ha from the Canadian border 

to south of Lake Chelan and includes North Cascades National Park and Ross Lake 

and Lake Chelan national recreation areas. The Stephen Mather Wilderness covers 

93 percent of the park, and there are five research natural areas within the borders. 

Rugged topography and nearly 3000 m of vertical relief result in diverse biophysical environments and ecosystems. Lake Chelan, the focus of Lake Chelan National 

Recreation Area, is the third deepest natural lake in the United States. Home to 300 

glaciers, NOCA contains over half of all glacial ice mass in the contiguous United 

Mount Rainier is an 

active volcano with 

the largest single-peak 

glacier system in the 

Pacific Northwest.
21

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

States. The park also has several large rivers including the Skagit, Nooksack, and 

Stehekin. Many archaeological sites are found near these rivers and more sites have 

recently been identified at higher elevations (Mierendorf 2004).

Although NOCA is now recognized for recreational opportunities and preservation of natural resources, the land was originally used for resource extraction. Logging operations and mining began in the 1870s. Sheep herding and grazing was also 

attempted in the northern Cascade Range but was abandoned in the 1940s because 

of the difficulty of herding sheep in high meadows. The potential for hydroelectric 

power was also recognized early when Seattle City Light built dams and railroads 

in the North Cascades in the 1920s and 1930s. Diablo Dam was completed in 1929 

and Ross Dam in 1949, and Gorge Dam was built in 1919 and rebuilt in 1950 and 

1961 (Thompson 1970). Collectively known as the Skagit River Hydroelectric 

Project, the facilities associated with these dams generate 711 megawatts of power, 

about 25 percent of the electrical usage for the Seattle region. 

The idea for a national park in the North Cascades was proposed about 75 years 

before it became official in 1969 (Louter 1998, North Cascades Study Team 1965) 

because of competition with timber and mining interests in the surrounding region, 

but the area was still enjoyed for many forms of recreation. The public desire to preserve the North Cascades persisted, and the park was created to preserve the natural 

features and majestic mountain scenery of the region, provide public recreation and 

enjoyment, and conserve scenic, scientific, and historic values of the land. 

Early conflict over management and use at NOCA focused on proposals for 

road construction, with some people in favor of new roads to provide recreational 

access, and others in favor or maintaining a remote environment. The North 

Cascades Highway, which opened in 1972, bisects the park from west to east and is 

the primary access route for most visitors. The Cascade River Road and Stehekin 

Valley Road, both unpaved, are the only other major roads in the park. After 

the North Cascades Highway opened, park visitation increased from 250,000 to 

750,000 people, prompting an expansion in campsites and revegetation of subalpine 

meadows that were being degraded by visitors (Louter 1998). Visitors to NOCA 

pursue recreation activities including scenic driving on the North Cascades Highway, backpacking, camping, and hiking. Recreational visits to NOCA declined from 

27,739 in 2001 to 19,208 in 2011, but backcountry camping remained fairly steady 

during that time. Recreational visits at Ross Lake National Recreation Area have 

increased from 331,343 in 2001 to 728,353 in 2011, and recreational visits at Lake 

Chelan National Recreation Area increased from 25,000 to 43,827 during that time.
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National Park Service management policies (USDI NPS 2006) establish the 

framework and direction for management decisions in national parks. Park-specific 

foundation statements and general management plans of NOCA and MORA summarize the established purpose for each park, the significance of the resources for 

which it was established, and provide a shared vision for resource conditions and 

visitor experiences that fulfill the purpose of each park. General management plans 

define strategic goals for park management over the next 15 to 20 years, and implementation plans identify short-term (5 years) goals and objectives. The broad goals 

of the NPS are to understand and protect the inherent integrity of natural resources, 

processes, systems, and values, while providing meaningful and appropriate opportunities for the public to enjoy the parks (USDI NPS 2006). Management activities 

at NOCA and MORA are also regulated by the Wilderness Act (1964), Wild and 

Scenic Rivers Act (1968), National Environmental Policy Act (1969), Clean Air Act 

(1970), Endangered Species Act (1973), and Clean Water Act (1977). 

Literature Cited

Burtchard, G.C. 1998 [reprinted 2003]. Environment, prehistory, and 

archaeology of Mount Rainier National Park, Washington. http://www.nps.gov/

history/history/online_books/mora/archaeology/index.htm. (20 July 2011).

Catton, T. 1996. Wonderland: an administrative history of Mount Rainier National 

Park. http://www.nps.gov/history/history/online_books/mora/adhi/index.htm.

(25 July 2011).

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. s/s 1251 et seq.

Endangered Species Act of 1973; 16 U.S.C. 1531-1536, 1538–1540.

Franklin, J.F.; Moir, W.H.; Hemstrom, M.A. [et al.]. 1988. The forest 

communities of Mount Rainier National Park. Scientific Monograph Series No. 

19. Washington, DC: U.S. Department of the Interior, National Park Service. 

http://www.nps.gov/history/history/_books/science/19/index.htm. (20 July 2011).

Louter, D. 1998. Contested terrain: North Cascades National Park Complex, 

Washington, an administrative history. Seattle: National Park Service. 338 p. 

http://www.nps.gov//history/online_books/noca/adhi/index.htm. (4 August 2011).

Mierendorf, R.R. 2004. Archaeology of the Little Beaver Watershed: North 

Cascades National Park Complex, Whatcom County, Washington. http://www.

nps.gov/history/history/online_books/noca/mierendorf/index.htm.

(4 August 2011).
23

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Mount Baker Foothills Economic Development Association. 2004. The Mt. 

Baker Foothills Chain of Trails concept plan. Bellingham, WA: Whatcom 

Council of Governments. http://wcog.org/documents/chain-of-trails-conceptplan/. (8 August 2011).

National Climate Extremes Committee. 2012. National Oceanographic and 

Atmospheric Administration, National Climate Extremes Committee. http://

www.ncdc.noaa.gov/extremes/ncec/. (5 September 2012).

National Environmental Policy Act of 1969; 42 U.S.C. 4321 et seq.

National Park Service Organic Act of 1916; 39 Stat. 535; 16 U.S.C. 1–4. 

North Cascades Study Team. 1965. The North Cascades: a report to the 

Secretary of the Interior and the Secretary of Agriculture. Washington, DC: 

U.S. Department of the Interior and U.S. Department of Agriculture. 190 p.

Thompson, E.N. 1970. North Cascades N.P., Ross Lake N.R.A. & Lake Chelan 

N.R.A. history basic data. Washington, DC: U.S. Department of the Interior, 

National Park Service, Office of History and Historic Architecture, Eastern 

Service Center. 301 p. http://www.nps.gov/history/history/online_books/noca/

hbd/index.htm. (August 4 2011).

U.S. Department of the Interior National Park Service [USDI NPS]. 2006. 

Management policies 2006. Washington, DC: U.S. Government Printing Office. 

179 p. http://www.nps.gov/policy/MP2006.pdf. (4 September 2012). 

Washington State Wilderness Act of 1984; 98 Stat. 339.

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

Wilderness Act of 1964; 16 U.S.C. 1121, 1131–1136.
24

general technical report pnw-gtr-892
25

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Weather is the condition of the atmosphere at a specific place in the short term 

(minutes to weeks). Climate is the mean weather conditions over a longer period of 

time (months, seasons, years, or thousands of years) and includes variables such as 

precipitation and temperature (Intergovernmental Panel for Climate Change [IPCC] 

2007). In addition to the mean, extremes and variability are also key features of climate and these statistics of climate are typically described for a 30-year period. In 

the Pacific Northwest (PNW), annual and decadal variability are important aspects 

of regional climate that are driven by semipredictable, natural interactions between 

the ocean and atmosphere. In contrast, climate change, or trends in climate over 

several decades, is driven by large-scale physical factors that influence regional or 

global climate (i.e., climate forcings). Climate forcings can be natural (e.g., changes 

in the Earth’s orbit) or caused by humans (e.g., changes in atmospheric concentrations of greenhouse gasses that affect the heat balance of the Earth). 

In the following sections, we describe spatial and temporal means, variability, 

and trends in historical and future climate in the PNW. Climatic variability and 

trends shape ecological and hydrologic processes with implications for ecosystem 

services and management of natural resources. These climate data and projections 

informed the North Cascadia Adaptation Partnership (NCAP) vulnerability assessment and adaptation planning process.

Climate of the Pacific Northwest

Climate in the North Cascade Range (defined here as Mount Rainier north to 

the Canadian border) is driven by the regional climate of the PNW and mediated 

by local effects of mountainous topography and proximity to the Pacific Ocean. 

Regionally, most precipitation falls in the winter half of the year (about 70 percent 

or more of the annual total) and relatively little falls in the summer half of the year 

(about 30 percent or less). The western slopes of the Cascade Range have a maritime climate that is greatly influenced by the Pacific Ocean and Puget Sound, 

1 Jeremy S. Littell is a research scientist, U.S. Department of the Interior, Alaska Climate 

Center, 4210 University Drive, Anchorage, AK 99508 (formerly research scientist, University of Washington, College of the Environment, Climate Impacts Group, Seattle, WA); 

and Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle City 

Light, 700 5th Avenue, Seattle, WA 98124 (formerly research biologist, U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire 

Sciences Laboratory, Seattle, WA).

Chapter 3: Climate and Climate Change in the 

North Cascade Range

Jeremy S. Littell and Crystal L. Raymond1
26

general technical report pnw-gtr-892

whereas the eastern slopes of the Cascade Range have a continental climate 

dominated by the orographic effect of the Cascade Range. The maritime climate 

of the western Cascades has relatively warm winters and cool summers compared 

to the eastern Cascades. Diurnal and seasonal temperature ranges (differences 

between lows and highs) are narrower in the western Cascades than the eastern 

Cascades. More precipitation falls on the west and southwest (windward) sides of 

the Cascades, particularly from November to March, than on the eastern slopes of 

the Cascades (leeward). In the Cascade Range, precipitation and temperature also 

vary with elevation. Higher elevations receive more precipitation and have lower 

temperatures, resulting in higher winter snowfall and spring snowpack. 

Regional climate varies significantly through time. The proximity of the PNW 

to the Pacific Ocean means that trends in large-scale interactions between the ocean 

and atmosphere affect climate of the region. The El Niño-Southern Oscillation 

(ENSO) originates in the tropical Pacific but influences the winter temperature and 

precipitation in the PNW. The ENSO cycles between El Niño and La Niña events 

every few years, with abnormally warm, dry winters more likely during El Niño 

events and abnormally wet winters more likely during La Niña events. The Pacific 

Decadal Oscillation (PDO) affects PNW winter climate similarly to ENSO, but it 

is a longer term (decadal) pattern of variation in the extra-tropical Pacific. Cool 

phases of the PDO have a similar influence on PNW climate as La Niña events. 

These features of Pacific Ocean circulation patterns are responsible for much of the 

temporal variability in the region’s climate over the historical record, which shows 

warm, dry winters in the early 20th century, followed by cool wet winters in the 

middle 20th century, and a return to warmer, drier conditions in the 1970s to 1990s.

Historical Climate Observations and Trends in the 

Pacific Northwest

In the PNW, several networks of weather stations monitor and record weather. 

Most analyses of climate (long-term trends in weather) require many decades of 

complete daily observations to adequately describe the means, variability, and 

trends in climate at a location. Daily observations of temperature and precipitation 

are recorded at locations around the United States as part of the National Weather 

Service Cooperative Observer Network (COOP), and records for the PNW can be 

found at the Western Regional Climate Center. Hundreds of COOP stations in the 

PNW, and approximately 25 in the north and central Cascades, record weather data 

relevant to management units in the NCAP. High-quality data from COOP stations 

for most of the 20th century (usually starting between 1895 and 1920) are archived 

as part of the U.S. Historical Climatology Network (HCN), but only the Longmire 
27

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

(Mount Rainier National Park [MORA]) and Stehekin (North Cascades National 

Park Complex [NOCA]) records are of sufficient length and quality to be HCN 

stations.

Based on historical records, mean annual temperature increased 0.8 °C in the 

PNW between 1920 and 2000 (Mote 2003). The first decade of the 21st century 

(2001–2010) was tied with the previous decade (1991–2000) for the warmest in the 

PNW since comprehensive observations began around 1920. An analysis of HCN 

stations from the PNW and Columbia Basin region shows similar trends for the 

period of 1950 to 2006, with increases in minimum and maximum temperatures of 

0.18 °C per decade for a total of 1.0 °C for the time period (Littell et al. 2011). During this time, 84 percent of HCN stations in the PNW showed an increase in annual 

minimum temperature of 0.5 °C or more, whereas only 1 percent of stations showed 

a decrease of more than 0.5 °C (Littell et al. 2011). Most stations showed significant 

increases in minimum (80 percent of stations) and maximum temperature (71 percent of stations), whereas decreases were not statistically significant. 

The national forests and national parks in the NCAP are at relatively high 

elevations in the PNW, and few stations in these units have long-term observations. 

Thus data are limited, making it difficult to determine whether the climate at higher 

elevations in the north and central Cascades is responding similarly to the rest of 

the PNW. The two longest and highest quality temperature records are from Longmire and Stehekin and both stations show increasing temperature trends (fig. 3.1).

In the PNW, annual precipitation increased slightly over the 1920–2000 period 

(Mote 2003), but precipitation is more variable relative to the mean than is temperature, so trends in precipitation are small compared to interannual variability. Similarly, analysis of precipitation trends from all HCN stations in the Columbia Basin 

for the period of 1950 to 2006 showed high spatial variability. Twenty-one percent 

of HCN stations showed declines in precipitation greater than 1 cm over the period, 

whereas 4 percent of stations showed increases in annual precipitation greater than 

1 cm (Littell et al. 2011). Most stations that recorded an increase in precipitation 

were west of the Cascade crest, whereas most stations that recorded a decrease 

were east of the crest. Few stations in the North Cascades have long-term records of 

precipitation, but the precipitation record from Stehekin agrees well with the PNW 

regional trend in terms of interannual variability, although mean precipitation at 

Stehekin is higher than the regionally averaged mean precipitation (fig. 3.2).

Trends in temperature recorded by the COOP stations in the two national parks 

in the NCAP give an indication of climate trends at high elevation. The COOP 

stations recorded temperature in NOCA from 1950 to the present and in MORA 

from 1970 to the present. Records from most COOP stations show at least modest 

Mean annual 

temperature increased 

0.8 °C in the Pacific 

Northwest between 

1920 and 2000.
28

general technical report pnw-gtr-892

Figure 3.1—Annual average temperatures for Longmire, Washington (Mount Rainier National Park 

[MORA], 1914–2011), and Stehekin, Washington (North Cascades National Park Complex [NOCA], 

1917–2011). The trend for Longmire is about 0.1 °C increase per decade, and the trend for Stehekin is 

about 0.2 °C increase per decade. High-quality National Weather Station Cooperative Observer Network data for most of the 20th century (usually starting between 1895 and 1920 in the Northwest) are 

archived as part the U.S. Historical Climatology Network (HCN). For the North Cascadia Adaptation 

Partnership region, only the Longmire and Stehekin records are of sufficient length and quality to be 

HCN stations. (Data: National Climatic Data Center; Menne et al. 2009.)

Figure 3.2—Observed annual precipitation (Washington, Oregon, Idaho—gray line) and precipitation recorded at the Stehekin, Washington, station (red line) during the 20th century. The blue line 

shows the longer term (about 20 years) average precipitation and illustrates the decadal variability 

characteristic of the Pacific Northwest. The horizontal line represents average conditions during 

the period of record. (Data: National Climatic Data Center (NCDC). Stehekin data from NCDC and 

Menne et al. 2009.)
29

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

increases in mean temperature across the period of observation, but not all records 

show increases in maximum temperature. Agreement among stations in NOCA 

is stronger than agreement among stations in MORA, perhaps because there are 

more stations to compare in NOCA. However, COOP station records, unlike HCN 

station records, do not have estimations for missing values, time of observation, or 

station location biases correction, and therefore are more likely than HCN stations 

to contain spurious trends.

Snowpack (along with temperature and precipitation) is measured as both 

snow depth and snow water equivalent (SWE, the amount of water entrained in the 

snowpack) at automated SNOTEL stations monitored by the U.S. Natural Resources 

Conservation Service. Snowpack records extend back to the 1930s to 1950s at some 

sites, but most SNOTEL stations were established between the 1970s and 2000s, so 

the temporal length of the snowpack record varies greatly within the region. 

In the Cascades in Washington, April 1 SWE has declined 15 to 35 percent 

from the middle of the 20th century to 2006 (Mote et al. 2008). This range is the 

best estimate based on a combined analysis of historical observations and hydrologic modeling. This range also reflects different starting times for the analysis 

(1930 to 1970), which are corrected for the number of observation stations and the 

elevations of these stations. Cycles of ENSO and PDO contribute to the variability 

in the observed record of April 1 SWE during the 20th century, but these cycles do 

not explain the negative trend over the time period. The long-term decline in April 

1 SWE is dominated by the increasing trend in temperature over the same period 

(Mote et al. 2008). The strong influence of warming on the negative trend in SWE 

is supported by observations of larger declines in SWE at low-elevation stations and 

smaller declines or increases in SWE at high-elevation stations (Mote et al. 2005), 

where warming is not sufficient to convert precipitation from snow to rain. Observations of precipitation show an increasing trend for the 20th century (Mote 2003), 

but variability is high. This variation in precipitation contributes to variability and 

short-term trends SWE, but the long-term trend is dominated by temperature (Mote 

et al. 2008). 

Stations in the national parks in the NCAP provide an indication of trends in 

precipitation and snowpack at high elevations. Most stations in MORA and NOCA 

show no trend in precipitation for 1970 to the present. The NOCA stations show 

prominent declines in snow depth. The three stations in MORA show a decline, an 

increase, and a flat trend in snow depth, but the increasing trend in MORA (Longmire COOP station) is for a shorter time period that begins in 1975, near a lower 

point in the longer regional snowpack record. Trends in SWE recorded at SNOTEL 

and snow course stations in MORA and NOCA show high variation; nine stations 

show a decrease and four stations show a flat trend. 
30

general technical report pnw-gtr-892

Future Climate in the Pacific Northwest

Models, Methods, and Data Used for Climate Projections

Future climate in the North Cascades is best described as the expected regional 

changes in temperature and precipitation and their effects on subregional hydrology. 

Changes in regional (PNW) climate can be projected using global climate models 

(GCMs) that combine natural and anthropogenic climate forcings with gridded 

atmosphere-ocean models that have the capability to resolve climate dynamics 

affecting large regions (about 100 to 1000 km). The Intergovernmental Panel on 

Climate Change Fourth Assessment (IPCC AR4) report relied on model results 

from 15 to 20 GCMs to project a range of potential changes in global climate 

(model projections are archived and distributed as World Climate Research Programme Coupled Model Intercomparison Project phase 3 [CMIP3] multimodel 

dataset) (Meehl et al. 2007). Changes in climate at finer resolution can be estimated 

by “downscaling” projected regional changes in future climate to local conditions 

based on historical relationships between coarse- and fine-scale climate.

Scientists from the University of Washington, Climate Impacts Group, and 

partners developed datasets of downscaled climate and hydrologic projections to 

support the development of vulnerability assessments and adaptation plans by land 

and water resource managers in the PNW (box 3.1). Methods and results, as well 

as archives of the data in grid and summarized forms, are available at http://cses.

washington.edu. See box 3.1 for a summary of available datasets and Web links to 

access the datasets. For this vulnerability assessment, we used two sources of climate data. For projections of most climatic variables, we used the analysis by Littell 

et al. (2011), which summarizes climate and hydrologic variables for the Western 

United States. For projections of streamflow, including peak flows and low flows, 

we used data and information from the Columbia Basin Climate Change Scenarios 

Project (Hamlet et al. 2010). Hamlet et al. (2010) developed a comprehensive database of historical and future hydrologic projections for 297 streamflow locations 

in the Columbia River basin to support long-range planning for water resources. 

These two sources of data provide similar projections of future climate and related 

hydrologic variables for the PNW but differ slightly in the GCMs included in the 

ensemble means and the statistical methods used to downscale coarse projections 

from GCMs for regional analyses at finer spatial (about 6 km) and temporal scales. 

For scenarios of future climate for the North Cascades, we reviewed downscaled GCM projections of temperature and precipitation for the PNW/Columbia 

Basin as developed and analyzed by Littell et al. (2011). Projecting regional climate 

does not require using all 19 GCMs, and careful selection of GCMs can limit the 
31

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Box 3.1—Climate and hydrologic datasets to support 

vulnerability assessments and adaptation planning for

natural resource management

Columbia Basin Climate Change Scenarios project— 

Hamlet et al. (2010) developed a comprehensive database of simulated hydrologic 

data incorporating climate change information from the Intergovernmental Panel 

on Climate Change Fourth Assessment Report to support long-term water resources 

planning in the Pacific Northwest/Columbia River basin. These projections can be 

used for vulnerability assessments and adaptation planning for terrestrial, fluvial, and 

coastal marine ecosystems. The final products include a set of hydrologic databases 

for 297 streamflow locations in the Columbia River basin and geographic information 

system layers for hydrologic and meteorological variables. All datasets, available at 

http://www.hydro.washington.edu/2860, are designed to serve a diverse community 

of resource managers. 

Regional climate and hydrologic change in the northern U.S. Rockies and 

Pacific Northwest: internally consistent projections of future climate for 

resource management—

Littell et al. (2011) developed consistent historical and future downscaled climate and 

hydrologic data for four river basins in the Western United States (Columbia River 

basin, upper Missouri River basin, upper Colorado River basin, and Great Basin). 

Historical and future hydrologic model output for several variables is available at 

about 6-km resolution for the extent of the four river basins. The variables were selected based on their relevance for vulnerability assessments and adaptation planning for resource management agencies. Variables summarized include temperature, 

precipitation, snow water equivalent, snow statistics, evapotranspiration, soil moisture, and several other hydrologic variables. Data are summarized for Bailey ecosections, Omernik level III ecoregions, and hydrologic unit code levels 4 and 5 basins. 

Gridded data and summarized data are available at Climate Impacts Group (n.d.[b]) 

and USDA FS (n.d.). This project builds on the research efforts of the Columbia Basin 

Climate Change Scenarios project (Hamlet et al. 2010) and Washington Climate 

Change Impacts Assessment (Elsner et al. 2009).

Historical and future projected changes in snow water equivalent for Oregon

and Washington— 

Mauger et al. (2011) used downscaled climate projections to generate high-resolution 

(800 m) simulations of snow water equivalent (SWE) for Oregon and Washington. 

The SWE was simulated using a version of the variable infiltration capacity (VIC) 

macroscale hydrologic model (Elsner et al. 2010, after Liang et al. 1996), modified to 

include terrain slope and aspect. The VIC simulations were implemented using up to 

five subgrid elevation bands within each grid cell, along with interpolated parameter 

files derived from Hamlet et al. (2010). Fine-scale simulations of SWE were generated 

for a historical period (1915–2006) and three scenarios for the 2040s using the A1B 

emissions scenario—an ensemble of the 10 best performing GCMs and two bracketing models (Littell et al. 2011). Data and methods are available from the Climate 

Impacts Group (n.d.[a]).
32

general technical report pnw-gtr-892

effect of poorly performing models on projections for a particular region (Littell et 

al. 2011, Mote and Salathé 2010). Littell et al. (2011) evaluated the performance of 

the 19 IPCC AR4 GCMs based on fidelity to observed seasonal and annual climate 

trends and selected a subset of 10 models (an ensemble) that perform well against 

several metrics focused on the northern and central Rockies. The development 

of this ensemble is based on rigorously evaluated climate models. The approach 

rejects models that do not accurately simulate the historical climate (temperature 

trend, precipitation seasonality, etc.), and the remaining models are assumed to have 

reasonable regional capability. However, any single model that captures the historical climate is not guaranteed to project future climate accurately. There are likely to 

be interactions in future climate and decadal variability that limit the performance 

of a single model. Similarly, models that perform poorly against historical data may, 

for reasons currently unknown, actually capture future dynamics well.

The mean of the 10-model ensemble averages differences associated with 

individual GCMs, and this mean reduces the chance that any single model’s unique 

approach to projecting future climate would lead to a severe bias in downscaled 

climate for the region. Although most GCMs project similar global trends, their 

internal dynamics and resolution can lead to substantially different local projections. The ensemble mean can be considered a “robust” estimate of future climate, 

but it is not necessarily a more likely future than any single model. 

Scenarios of greenhouse gas (GHG) emissions over time are required to drive 

GCM projections of future climate. These emissions scenarios are “story lines” 

that incorporate scenarios of economic development, population growth, mitigation 

efforts, and changes in technology to determine potential future emissions of GHGs 

(Nakicenovic et al. 2000). Commonly used emissions scenarios are B1, A1B, and 

A2. The scenarios are similar in the mid-21st century, but the A2 scenario produces 

the most warming by the end of the 21st century. 

The A1B scenario has been used in regional analyses for the PNW (Elsner et 

al. 2009), and we primarily use A1B for this vulnerability assessment for several 

reasons. The A1B scenario is a medium-high emissions scenario reflecting rapid 

increases in GHGs in the early 21st century followed by substantial reductions in 

the second half of the 21st century, which slows the rate of warming. Thus A1B 

results in more warming than the A2 or B1 scenarios until the 2040s or 2050s, the 

timeframe relevant to many vulnerability assessments. The A1B scenario, however, 

should not be considered a “worst case” scenario because the full sensitivity of the 

climate system could be higher than the temperatures expected under A1B and 
33

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

because individual climate models project more warming than the ensemble mean 

(Roe and Baker 2007). The A1B scenario is also most consistent with current GHG 

emissions (Raupach et al. 2007). 

Projections of Temperature and Precipitation for the Pacific 

Northwest

For the PNW, the average response of the 10-model ensemble for the A1B emissions 

scenario is for temperature to continue to increase, with warming on average of 

2.1 °C by the 2040s (average of years in the 30-year window from 2030 to 2059), 

and 3.8 °C by the 2080s (2070–2099) (Littell et al. 2011). This projected increase 

in temperature would put 2040s average temperatures at the upper end of the 

historical range and 2080s average temperatures mostly outside of the historical 

range. Increasing trends in temperature have been attributed, at least partially, to 

human emissions of GHGs (such as carbon dioxide) (Stott 2003), and as emissions 

increase, temperature is expected to increase, although interannual variability will 

be observable. 

The seasonality of changes in temperature affects hydrology, snowpack, and 

ecological processes. Temperature is projected to increase in all seasons, but the 

biggest increases are projected for summer (June, July, and August) (fig. 3.3). This 

seasonal difference in future projections differs from the seasonal differences 

observed in the 20th century warming trend, which indicate greater warming in 

winter in the PNW (Mote 2003). There are potential feedbacks associated with 

warming that are seasonally dependent (e.g., reduced snowpack may accelerate 

warming in winter and lower soil moisture may accelerate warning in summer), but 

the effect of these feedbacks is uncertain. Furthermore, both historical observations 

and future projections of temperature by season are highly variable, so differences 

between seasons are less certain than annual trends. 

The range of GCM projections of future precipitation in the PNW is large, and 

results vary among models with some projecting higher annual precipitation and 

others projecting lower (Littell et al. 2011). For the A1B scenario, the 10-model 

ensemble mean is no change in annual precipitation for the 2040s and a 2-percent 

increase in precipitation for the 2080s (Littell et al. 2011) (table 3.1). The PNW will 

continue to experience high interannual variability in precipitation, and trends 

associated with climate change may be difficult to detect against this background of 

annual and decadal variability. However, seasonal changes in precipitation may be 

more perceptible and important for understanding effects of changes in precipitation on hydrologic process such as streamflow and snowpack. Slight increases in 

Air temperature is 

projected to increase 

2.1 °C by the 2040s and 

3.8 °C by the 2080s.
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general technical report pnw-gtr-892

Figure 3.3—Range of projected changes in temperature (relative to 1970–1999) for the Columbia 

River basin/Pacific Northwest for the 2040s (top) and 2080s (bottom) for each season (letters indicate 

first letter of the month). In each box-and-whisker trio, the leftmost is for emissions scenario B1, 

center for A1B, and right for A2; circles are individual model values. Box-and-whisker plots indicate 

10th and 90th percentiles (whiskers), 75th percentiles (box ends), and median (solid middle bar) for 

each season and scenario. White bars indicate mean of deltas for global climate models. (Data 

source: Littell et al. 2011.)
35

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 3.1—Projected changes in seasonal and annual temperature and precipitation for 

the Columbia River basin/Pacific Northwest for the A1B emissions scenario and three 

GCMs (a 10-model ensemble and two bracketing models, PCM1 and MIROC 3.2) 

Temperature change Precipitation change

Years Monthsa

PCM1

(least 

warming

and drier)

10-model 

ensemble 

mean

(moderate 

warming)

MIROC 3.2

(most 

warming,

wetter)

PCM1

(least 

warming,

and drier)

10-model 

ensemble 

mean

(moderate 

warming

MIROC 3.2

(most 

warming,

wetter)

- - - - - - - - - - - - °C - - - - - - - - - - - - - - - - - - - - - -Percentage- - - - - - - - - -

2040s DJF 2.0 1.8 2.7 -8 4 6

MAM 1.3 1.7 3.0 10 4 1

JJA 1.9 2.7 2.8 -3 -10 -8

SON 2.0 2.2 2.4 -6 3 17

Annual 1.8 2.1 2.7 -2 0 4

2080s DJF 3.2 3.4 4.6 9 9 9

MAM 2.0 3.2 4.8 5 5 9

JJA 3.3 4.9 4.9 -19 -15 -30

SON 2.4 3.9 4.3 -13 9 14

Annual 2.7 3.8 4.6 -5 2 0

a Letters indicate the first letter of each month. GCM = global climate model.

precipitation are projected for all seasons except summer, which is projected to have 

a 10-percent decrease in precipitation by the 2040s (fig. 3.4). 

Variation in future climate projected by different GCMs can be used to represent scenarios of future climate. Littell et al. (2011) selected two GCMs (PCM1 

and MIROC 3.2) that “bracket” the range of future temperature and precipitation 

projected by the 10-model ensemble. The two bracketing models were selected 

based on changes in summer temperature and precipitation. The bracketing models 

were originally chosen for the upper Missouri River basin and do not span the 

range for all variables in the PNW, particularly with respect to effects on snowpack. 

Nevertheless, the bracketing models provide a range of possible future climatic 

outcomes, so we use them in this assessment as well. 

In comparison with the ensemble mean, the PCM1 model simulates relatively 

small increases in annual temperature and slightly drier annual conditions in the 

PNW (table 3.1). This scenario is labeled “least warming and drier” for subsequent 

chapters of this report. The MIROC 3.2 model simulates relatively large annual 

increase in temperature and wetter annual conditions for the 2040s (table 3.1) 

(Littell et al. 2011). This scenario is labeled “most warming and wetter.” The 
36

general technical report pnw-gtr-892

Figure 3.4—Range of projected changes in precipitation (relative to 1970–1999) for the Columbia 

River basin/Pacific Northwest for the 2040s (top) and 2080s (bottom) for each season (letters 

indicate first letter of the month). In each box-and-whisker trio, the leftmost is for emissions scenario 

B1, center for A1B, and right for A2; circles are individual model values. Box-and-whisker plots 

indicate 10th and 90th percentiles (whiskers), 75th percentiles (box ends), and median (solid middle 

bar) for each season and scenario. White bars indicate mean of deltas for global climate models. 

(Data source: Littell et al. 2011.)
37

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

ensemble mean for annual temperature and precipitation falls within the range of 

bracketing models (table 3.1) and is labeled “moderate warming.” These scenario 

labels are based on annual means for the 2040s; some seasonal means of precipitation (e.g., winter temperature) do not follow this pattern (table 3.1). For example, 

despite being a drier annual scenario, PCM1 projects a larger increase in spring 

(March, April, May) precipitation relative to the ensemble mean or MIROC 3.2. 

Furthermore, relative differences between the two bracketing models and the 

ensemble mean differ for projections for the 2080s. 

These three scenarios (PCM 1, MIROC 3.2, and the ensemble mean) of changes 

in temperature and precipitation were downscaled (Littell et al. 2011) and used for 

hydrologic modeling (Elsner et al. 2010) of additional climatic variables. Regional 

projections were downscaled to 6-km resolution using a modified delta method, 

which applies regional changes in temperature and precipitation to historical 

temperature and precipitation records. This method captures changes in the seasonality and spatial variability in temperature and precipitation, but fine-scale temporal 

variability is limited to only the variability captured in the historical record. Even 

at the downscaled resolution of 6 km, individual valleys and mountains within the 

Cascades cannot be distinguished and thus the influence of microtopography on 

climate is not represented. 

Downscaled climate projections indicate that summer (June-July-August) 

temperatures are projected to increase throughout the North Cascades with slightly 

larger increases projected for the eastern Cascades (fig. 3.5). Winter precipitation 

(October through March) is projected to increase throughout much of the North 

Cascades with the magnitude of increases varying by GCM (fig. 3.6); the largest 

increases are projected for the northern and eastern portions of the region. 

Elsner et al. (2010) used downscaled climate data as inputs to a macroscale 

hydrologic model, the Variable Infiltration Capacity (VIC) model, which simulates 

several hydrologic variables that are relevant to ecological processes such as snowpack, soil moisture, and water balance deficit. Projections for these variables are 

presented in subsequent chapters on hydrology (chapter 4) and vegetation (chapter 

5) in which their relevance to adapting resource management to climate change 

is discussed. We focus on projections of these variables for the 2040s because for 

that timeframe, climate is markedly different in most projections from the current 

climate, but it is not far enough into the future that uncertainty associated with 

emissions scenarios is greater than uncertainty associated with changes in regional 

climate.

We drew from the large database of hydrologic scenarios for the Columbia 

River basin (Hamlet et al. 2010) for projected changes in streamflow used in the 

Summer temperatures 

and winter precipitation 

are projected to 

increase throughout the 

North Cascades.
38

general technical report pnw-gtr-892

Figure 3.5—Historical and future projections of summer temperature (June, July, and August) in the 

North Cascades. Projections were made using the A1B emissions scenario and three model configurations: an ensemble of 10 GCMs and two bracketing GCMs (one projecting less annual warming 

and drier conditions [PCM1], and the other projecting more annual warming and wetter conditions 

than the ensemble mean [MIROC 3.2]) for the 2040s.
39

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

vulnerability assessment of hydrology and access (chapter 4) and fish (chapter 7). 

The methods used to develop downscaled climate data and hydrologic model simulations are similar to methods described above. However, these projections were 

developed specifically for water resources planning in the Columbia River basin, so 

we use them in this assessment for projected changes in flood magnitude and low 

streamflow during the dry season. Hamlet et al. (2010) used a 10-model ensemble 

mean but did not use bracketing models. We include projections of these hydrologic 

variables for the 2080s, as well as the 2040s, because vulnerability assessments and 

adaptation planning for roads and infrastructure may benefit from this longer term 

perspective. 

Figure 3.6—Historical and future projections of winter precipitation (October through March) in the 

North Cascades. Projections were made using the A1B emissions scenario and three model configurations: an ensemble of 10 GCMs and two bracketing GCMs (one projecting less annual warming 

and drier conditions [PCM1], and the other projecting more annual warming and wetter conditions 

than the ensemble mean [MIROC 3.2]) for the 2040s.
40

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Uncertainty in Future Climate Projections

The GCMs are a balance between the minimum complexity necessary to characterize variability in global and regional climate and sufficient complexity to represent 

climate dynamics at fine spatial and temporal scales. Some aspects of climate and 

its drivers are less well understood than others (e.g., the role of atmospheric aerosols), thus climate models are uncertain. Each GCM has its own particular parameters that control climate dynamics, which may be slightly or substantially different 

than another model, although both may characterize historical climate well but for 

different reasons. 

Climate is dynamic and complex, so a certain forecast for a future 30-year 

period cannot be achieved, particularly not at a fine spatial scale (smaller than 

10 km). Dynamics, which the climate modeling community can forecast reasonably well, provide 6 to 12 months of predictive capability. Climate forcings (e.g., 

anthropogenic GHGs), which the climate modeling community also forecasts well, 

provide reasonable averages for 30-year periods. Between annual time scales and 

30-year future averages, variability is caused by climate dynamics and forcings, 

which interact in complex ways that are difficult to capture with climate modeling. 

The uncertainty and limitations of GCMs are unlikely to be resolved soon, so it is 

not feasible to wait for better models before moving ahead with adaptation. However, we currently have sufficient certainty, knowledge, and data for some aspects 

of future climate to move ahead with adaptation.

Uncertainty does not apply equally to all variables, and a recognition of which 

variables are more certain than others is useful for adaptation planning (Peterson 

et al. 2011). Projections of temperature are more certain than other variables, and 

projections of means are more certain than extremes. The relative rate and magnitude of changes in temperature are similar at local scales (e.g., a 6-km pixel within a 

watershed); for example, a given temperature normal is unlikely to increase 2 °C at 

Stehekin, Washington, but 10 °C at Leavenworth, Washington. However, the effects 

of changes in temperature on processes involving thresholds, such as rain versus 

snow for snowpack development, streamflow, or water balance deficit, require more 

local information on climate, soils, and vegetation. The capability to understand 

changes in these variables is better with downscaled climate projections than with 

regional models alone, but even statistical downscaling does not resolve some 

changes. For example, projections with regional climate models (dynamical weather 

forecasting models driven by output from GCMs) show that some areas (mid elevations) are likely to warm faster than the regional average because of local feedbacks 

(e.g., changes in snow albedo that increase the rate of spring warming). 
41

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

There are two additional sources of uncertainty external to climate modeling 

and downscaling that are important considerations for vulnerability assessments 

and adaptation planning: the sensitivity of the climate system to increases in GHGs 

and the future trajectory of GHG emissions. Equilibrium climate sensitivity is the 

amount of change in mean annual global surface air temperature that would result 

from a doubling of preindustrial atmospheric carbon dioxide. The true sensitivity 

is unknown, but Roe and Armour (2011) compared climate sensitivity estimated 

by three separate approaches to the sensitivity in IPCC AR4/CMIP3 GCMs. Their 

results suggest that the “worst case” (most warming) commonly available GCM 

and emissions scenario combination is not actually the worst plausible, but the “best 

case” (least warming) scenarios in the IPCC AR4/CMIP3 are close to the lowest 

climate sensitivity supported by observations and modeling. 

Future emissions could possibly be more or less than the range of emissions 

scenarios used to force the IPCC AR4 climate models, although more is perhaps 

more probable than less given recent research and documented emissions (Raupach 

et al. 2007). Trends in GHG emissions since 2006 are near the high end of emissions scenarios used to force climate models for the IPCC AR4, but not above all 

scenarios (Le Quéré et al. 2009, Manning et al. 2010, Raupauch et al. 2007). Uncertainties about climate sensitivity and future emissions suggest that planning for the 

“worst case” in the IPCC AR4 range of modeled futures is not unreasonable and 

may not even be sufficient to ensure resilience. Thus it is important to incorporate 

flexibility in management plans to account for uncertainties in climate, even when 

planning for the worst case future climate scenario. 

Acknowledgments

We thank colleagues at the University of Washington, Climate Impacts Group for 

their assistance with climate data and analysis. Jon Riedel provided a helpful review 

of this chapter. 

Literature Cited

Climate Impacts Group. [N.d.(a)]. Historic and future projected change in snow 

water equivalent (SWE) for Oregon and Washington. http://cses.washington.edu/

data/swe30s.shtml. (15 April 2013).

Climate Impacts Group [N.d.(b)]. Regional climate and hydrologic change: 

internally consistent future climate projections for resource management. 

http://cses.washington.edu/data/r1r6.shtml. (15 April 2013).
42

general technical report pnw-gtr-892

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.

Elsner, M.M.; Littell, J.; Whitely Binder, L., eds. 2009. The Washington climate 

change impacts assessment: evaluating Washington’s future in a changing 

climate. Seattle, WA: University of Washington, Joint Institute for the Study 

of the Atmosphere and Oceans, Center for Science in the Earth System. 402 p. 

http://cses.washington.edu/db/pdf/wacciareport681.pdf. (15 April 2013). 

Hamlet A.F.; Salathé, E.P.; Carrasco, P. 2010. Final report for the Columbia basin 

climate change scenarios project. Seattle, WA: University of Washington, Center 

for Science in the Earth System, Joint Institute for the Study of the Atmosphere 

and Ocean, Climate Impacts Group. 

Intergovernmental Panel on Climate Change [IPCC]. 2007. 2.3 Climate 

sensitivity and feedbacks. In: Pachauri, R.K.; Reisinger, A., eds. Climate change 

2007: synthesis report. 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.

Le Quéré, C.; Raupach, M.R.; Canadell, J.G. [et al.]. 2009. Trends in the sources 

and sinks of carbon dioxide. Nature Geosciences. 2: 831–836.

Liang, X.; Wood, E.F.; Lettenmaier, D.P. 1996. Surface soil moisture 

parameterization of the VIC-2L model: evaluation and modifications. Global and 

Planetary Change. 13: 195–206.

Littell, J.S.; Elsner, M.M.; Mauger, G.S. [et al.]. 2011. Regional climate and 

hydrologic change in the northern U.S. Rockies and Pacific Northwest: internally 

consistent projections of future climate for resource management. Preliminary 

project report, USDA FS JVA 09-JV-11015600-039. Seattle, WA: University of 

Washington, Center for Science in the Earth System, Joint Institute for the Study 

of the Atmosphere and Ocean, Climate Impacts Group. http://cses.washington.

edu/picea/USFS/pub/Littell_etal_2010/Littell_etal._2011_Regional_Climatic_

And_Hydrologic_Change_USFS_USFWS_JVA_17Apr11.pdf. (15 April 2013).

Manning, M.R.; Edmonds, J.; Emori, S. [et al.]. 2010. Misrepresentation of the 

IPCC CO2 emission scenarios. Nature Geoscience. 3: 376–377.
43

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Mauger, G. 2011. Summaries of 30 arc-second (~800m) snow products generated 

using the variable infiltration capacity (VIC) macroscale hydrologic model. 

[Database]. Seattle, WA: University of Washington, Center for Science in 

the Earth System, Joint Institute for the Study of the Atmosphere and Ocean, 

Climate Impacts Group. http://cses.washington.edu/picea/mauger/VIC_SNOW/

pub. (15 April 2013).

Meehl, G.; Covey, C.; Delworth, T. [et al.]. 2007. The WCRP CMIP3 

multi-model dataset: a new era in climate change research. Bulletin of the 

American Meteorological Society. 88: 1383–1394. 

Menne, M.J.; Williams, C.N.; Vose, R.S. 2009. The United States 

Historical Climatology Network monthly temperature data, version 2. 

Bulletin of the American Meteorological Society. 90: 993–1107.

Mote, P.W. 2003. Trends in temperature and precipitation in the Pacific 

Northwest during the twentieth century. Northwest Science. 77: 271–282.

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

Science. 12: 193–206

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

Climatic Change. 102: 29–50.

Nakicenovic, N.; Alcamo, J.; Davis, G. [et al.]. 2000. Special report on 

emissions scenarios, working group III, Intergovernmental Panel on 

Climate Change. Cambridge, United Kingdom: Cambridge University 

Press. 595 p.

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al]. 2011. Responding to 

climate change in national forests: a guidebook for developing adaptation 

options. Gen. Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 109 p.

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 of the United States of America. 104: 10288–10293.
44

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Roe, G.H.; Armour, K.C. 2011. How sensitive is climate sensitivity? 

Geophysical Research Letters. 38: L14708. doi:10.1029/2011GL047913.

Roe, G.H.; Baker, M.B. 2007. Why is climate sensitivity so unpredictable? 

Science. 318: 629–632.

Stott, P.A. 2003. Attribution of regional-scale temperature changes to 

anthropogenic and natural causes. Geophysical Research Letters. 30: 1728. 

doi:10.1029/2003GL017324.

U.S. Department of Agriculture, Forest Service [USDA FS]. [N.d.].

Regional climate and hydrological change in the northern US Rockies 

and Pacific Northwest. http://www.fs.fed.us/wwetac/threat_map/WWide_

Climate_Change.html. (15 April 2013). 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Introduction

Roads and trails built in the North Cascade Range of Washington over more than 

a century provided access for mineral prospectors, loggers, hunters, and tourists, 

bringing them closer to natural resources and recreational opportunities. The 

national forests and national parks in the North Cascades were created for resource 

development, protection, and enjoyment by the public. Providing access allowed 

for these objectives to be met, and access largely determined where these activities 

historically occurred. Today, reliable and strategic access is critical for people to 

recreate, extract resources, monitor and manage resources, and respond to emergencies. Access to public lands promotes use, stewardship, and appreciation of 

their value as a vital resource contributing to quality of life (Louter 2006). Access 

management balances these benefits with a wide range of other ecosystem services.

Climate change is expected to change access to public lands in forests and 

parks in the North Cascadia Adaptation Partnership (NCAP), which includes North 

Cascades National Park Complex [NOCA], Mount Rainier National Park [MORA], 

Mount Baker-Snoqualmie National Forest [MBSNF], and Okanogan-Wenatchee 

National Forest [OWNF]. Climate change has already affected ecosystems and the 

built environment in the Pacific Northwest (PNW), and these effects are projected 

to intensify in future decades. Impaired access to public lands reduces the ability of 

land managers to preserve, protect, and restore resources and to provide for public 

use of resources. An understanding of the current vulnerabilities and the pathways 

through which climate change affects access will enable U.S. Department of the 

Interior National Park Service (NPS) and U.S. Department of Agriculture Forest 

Service (USDA FS) land managers to identify and implement adaptation strategies

1 Ronda L. Strauch is a Ph.D. candidate, University of Washington, Department of Civil 

and Environmental Engineering, Box 352700, Seattle, WA 98195; Alan F. Hamlet is 

an assistant professor, Department of Civil and Environmental Engineering and Earth 

Sciences, University of Notre Dame, 257 Fitzpatrick Hall, Notre Dame, IN 46556 (formerly 

a research assistant professor, University of Washington, Department of Civil and Environmental Engineering, Seattle, WA); and Crystal L. Raymond is a climate change strategic 

advisor, City of Seattle, Seattle City Light, 700 5th Avenue, Seattle, WA 98124 (formerly 

research biologist, U.S. Department of Agriculture, Forest Service, Pacific Northwest 

Research Station, Pacific Wildland Fire Sciences Laboratory, Seattle, WA).

Chapter 4: Climate Change, Hydrology, 

and Access in the North Cascade Range

Ronda L. Strauch, Crystal L. Raymond, and Alan F. Hamlet1
46

general technical report pnw-gtr-892

that will maintain functioning ecosystem processes and natural resources in a 

changing environment, while providing continued and sustainable access for 

human use.

The NCAP held a workshop on climate change, hydrology, and access that 

convened more than 40 participants including resource managers, scientists, 

engineers, and recreation managers. Participants were affiliated with multiple 

agencies and organizations including NCAP national forests and national parks, 

USDA FS Pacific Northwest Research Station, University of Washington, Federal 

Highway Administration, Washington State Department of Transportation, city of 

Seattle, U.S. Environmental Protection Agency, The Mountaineers, National Parks 

and Conservation Association, and North Cascades Conservation Council. The 

workshop had four objectives:

• Identify key sensitivities of roads, trails, and infrastructure to changes in 

climate and hydrology.

• Review current access and travel management priorities and share management approaches that already consider climate or climate change.

• Use the latest scientific information on climate change and effects on 

hydrologic regimes to identify adaptation strategies and tactics.

• Identify opportunities to collaborate with partners to develop adaptation 

strategies and tactics that cross jurisdictional boundaries.

During the workshop, participants reviewed the latest science on the effects 

of climate change on snowpack and hydrology in the North Cascades. Box 4.1 

describes sources of climate data and vulnerability assessments relevant to hydrology and access in the PNW, many of which were reviewed during the workshop. 

Engineers, resource managers, and scientists from each national forest and national 

park presented information on current practices for transportation and access management (roads, trails, and facilities) in their unit, as well as case studies of flooding 

vulnerabilities and recent severe flood damage (particularly in MORA in 2006 and 

MBSNF in 2003 and 2006). Workshop participants worked collaboratively to identify adaptation options to reduce vulnerability to climate change and facilitate the 

transition to new states. The initial vulnerabilities and associated adaptation options 

identified in the workshop were refined with further literature review, data, and 

discussions with scientists and resource managers. The results of this vulnerability 

assessment and adaptation planning process are described in the sections below. 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Box 4.1—Publications relevant to climate change effects and adaptation options 

for hydrologic regimes and access in the Pacific Northwest

Over the past decade, several publications have discussed vulnerability and adaptation to climate change and 

many are relevant to access in the Pacific Northwest (box-table 4.1): an assessment of projected changes in climate in Washington (Elsner et al. 2009), current and anticipated impacts on transportation (Halofsky et al. 2011, 

MacArthur et al. 2012, WSDOT 2011), and adaptation planning guides (Peterson et al. 2011, Snover et al. 2007). 

These resources discuss climate change impacts on hydrologic regimes, roads, and access in greater detail and 

provide examples, approaches, and agency priorities.

Climate change vulnerability and adaptation reports with information relevant to hydrologic regimes 

and access in the Pacific Northwest (PNW)

Title Citation Description

Washington climate change impacts 

assessment

Elsner et al. (2009) Assessment of climate change impacts to 

eight sectors in Washington state

Comprehensive hydrologic database 

incorporating Intergovernmental Panel 

on Climate Change (IPCC) scenarios to 

support long-range water planning in the 

Columbia River basin

Hamlet et al. (2013) Most current simulated hydrologic data 

and report for PNW, incorporating 

IPCC’s fourth assessment report emission scenarios

Preparing for climate change: a guidebook 

for local, regional, and state governments

Snover et al. (2007) Guidebook for agencies to develop a 

climate change preparedness plan

Responding to climate change in national 

forests: a guidebook for developing adaptation options

Peterson et al. (2011) Guidebook for developing adaptation 

options for Forest Service lands

National roadmap for responding to climate 

change

USDA FS (2011a) Plan describing Forest Service priorities 

for responding to changing climate

National Park Service (NPS) climate change 

response strategy

USDI NPS (2010a) Provides strategic direction to the 

agency for addressing impacts of climate change

Climate change, hydrology, and road management at Olympic National Forest and 

Olympic National Park, chapter 4

Halofsky et al. (2011) Case study on climate change impacts, 

road management, and adaptation 

strategies

Potential Impacts of Climate Change on U.S. 

Transportation

Transportation 

Research Board (2008)

Synthesis and discussion of consequences of climate change for transportation 

infrastructure and operations

Climate impacts vulnerability assessment Washington Department of Transportation 

(2011)

Test of Federal Highway Administration conceptual climate risk assessment 

model to transportation in Washington 

state

Climate change impact assessment for surface transportation in PNW and AlaskaMacArthur et al. 

(2012)

Preliminary vulnerability assessment 

of surface transportation in PNW and 

Alaska 
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The Current Context for Access in the North Cascades 

Current Development and Access Needs

The transportation network in national forests and national parks in the NCAP 

includes roads, trails, docks, landing fields, and associated facilities. The two 

national forests and two national parks combined contain about 28 900 km of roads 

and trails, 98 percent of which are in national forests (table 4.1). The national forests 

have more kilometers of roads than trails, whereas the national parks have more 

kilometers of trails than roads. Of the existing roads, 850 km (5 percent) of roads 

are paved and 17 800 km are gravel. Road density is higher at low elevations and 

adjacent to major mountain passes, such as the west slopes of Interstate 90 near 

Snoqualmie Pass and north of Leavenworth on the east side of the Cascade Range 

(fig. 4.1). Roads and trails cross many streams and rivers because of the rugged 

topography and wet maritime climate of the western Cascades. Most (96 percent) 

known water crossings are culverts on the national forests (table 4.1), but many 

crossings or drainages have not been inventoried. Although most roads are on 

national forests, visitors often use these roads to access national parks, creating a 

strong interdependence of the road system (fig. 4.1). Docks and seaplanes provide 

access to lakes, and lakes and reservoirs are used to transport supplies to the communities of Hozomeen and Stehekin. Landing fields and helispots are operated for 

small planes and helicopters, which are used by visitors, as well as for fire management and resource monitoring. 

Table 4.1—Transportation infrastructure within the boundaries of management 

units in the North Cascadia Adaptation Partnership (NCAP) region, including 

roads and trails managed by other jurisdictions 

 Road Road

NCAP administrative unit Roads Trails culvertsa bridgesa

- - - - - - - - - - - Kilometers - - - - - - - - - - -

North Cascades National Park Complex 121 626 190 11

Mount Rainier National Park 170 453 739 30

Mount Baker-Snoqualmie National Forest 4373 2423 10,382 170

Okanogan-Wenatchee National Forest 13 995 6742 11,142 135

a Only culverts and bridges managed by the specified units are included. 

Data source: U.S. Forest Service, National Park Service, Washington 

Department of Transportation, and U.S. Federal Highway Administration (2011). 

The North Cascade 

Adaptation Partnership 

national forests and 

national parks contain 

about 28 900 km of 

roads and trails.
49

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Historically, the primary purpose of the road system in national forests was 

timber harvest. Reduced harvesting under the Northwest Forest Plan (NWFP) has 

substantially decreased the need for roads as anticipated in the land and resource 

management plans (i.e., forest plans) that were written before the NWFP (USDA 

and USDI 1994a, 1994b). However, population growth has increased demand for 

access for recreation. For example, recreation demand in the OWNF is now more 

than double the demand predicted in the 1990 forest plan.2 Hiking and camping

2

 Fee, L. 2007. Forest plan revision for the Colville and the Okanogan-Wenatchee national 

forests. Draft. Available online at: http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/

fsbdev3_053376.pdf. (11 November 2012).

Figure 4.1— Distribution of roads and trails within the two national forests 

and two national parks within the North Cascadia Adaptation Partnership 

region. The forests and parks cover a contiguous area of over 28 490 km2

(more than 2.4 million ha) and contain approximately 28 900 km of roads 

and trails. The density of roads is greater at low elevations and within 

forests, but trails are more common at higher elevations and in parks. Data 

were acquired from each federal jurisdiction’s geographic information 

system and includes all categories of roads and trails, except for usercreated routes. 
50

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are the most popular activities, but visitors are staying for shorter duration than in 

the past, often only 1 day. More than 60 percent of trips to national forests last 6 

hours or less; short visits concentrate human impacts on areas that are easily accessible (USDA FS 2010a). Demand is increasing for trail use by mountain bikes and 

motorized vehicles and for routes designated for off-highway vehicles, as well as for 

winter recreation (see footnote 2).

Visitation in all national parks has increased since their establishment and more 

than 1.8 million visitors traveled to MORA and NOCA in 2011. Fourteen percent of 

these visits were overnight stays, which is almost three times the national average 

for all national parks (Cui et al. 2013). Short-duration trips increase demand for 

easy access and parking, so although the duration of visits is decreasing at MORA 

and NOCA, these two parks are less affected compared to the national trend. Road 

building was minimized during park development, so higher visitation has led to 

traffic congestion, especially at MORA between June and September when 75 

percent of visitation occurs (USDI NPS 2001). High seasonal visitation stresses 

transportation management at MORA. Although all four units maintain some yearround access, many roads and facilities are closed in winter because of snow cover, 

especially in the two parks because roads are generally at higher elevation. 

Road and Trail Types and Conditions

Roads are classified by their designated use and material type. National parks 

classify roads into six classes by function: principal park road, connector park road, 

special purpose road, primitive park road, administrative access road, and restricted 

road. National forests divide roads into six categories (table 4.2). The MBSNF has 

4682 km of roads, with most (41 percent) suitable for passenger cars (table 4.2). The 

OWNF has 13 133 km of roads (excluding decommissioned roads); the majority (68 

percent) of roads are suitable for high-clearance cars and trucks or passenger cars. 

The national forests and national parks in the NCAP have four major east-west 

mountain passes: Washington Highway 20 crosses through NOCA, Washington 

Highways 410 and 123 pass through MORA, Washington Highway 2 passes 

through the MBSNF at Stevens Pass, and Interstate 90 passes through the MBSNF 

at Snoqualmie Pass. The first two passes are closed in winter because of snow, and 

the second two passes are open all year with regular snow and avalanche clearing, 

providing access to winter ski resorts and corridors for transporting goods and 

people between the east and west sides of the state. 

Access and recreation have a considerable impact on the economy in local 

communities. In 2011, the 1,038,229 visitors to MORA spent more than $33 million 

within 100 km of the park (Cui et al. 2013). The 791,388 visitors to NOCA spent 
51

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

more than $26 million within 100 km of the park complex (Cui et al. 2013), but 

this is likely an underestimate because many visitors drive through the park on the 

North Cascade Highway and State Highway 20 without stopping, so they are not 

counted (Stynes 2011). Access to national forests also provides significant economic 

benefit to the region. In the past decade, half of visitors live within 80 km, and average visitor spending is $13 billion per year in and near national forests nationwide 

(USDA FS 2010a). 

Climate Change Effects Relevant to Access

Changing Climate in the Pacific Northwest

In the sections below, we focus on three pathways through which changes in climate 

and hydrology directly influence access in mountain landscapes: (1) flooding and 

extreme low flows, (2) changes in snowpack, and (3) elevated winter soil moisture 

and landslide risk. Although climatic variability is partially predictable based 

on weather statistics over many years, climate can shift from observed historical 

patterns to different patterns encountered in only the distant past or potentially 

entirely new climate regimes (Milly et al. 2008). Projected (i.e., estimated based 

on models) shifts in temperature and precipitation for the 21st century based on 

increases in anthropogenic greenhouse gases are presented in chapter 3. Climate 

change is a global phenomenon, but regional expressions of climate change may 

differ substantially from global trends because of local factors, particularly over 

decades (IPCC 2007). Mountain ecosystems are particularly sensitive to climate 

Table 4.2—Kilometers of road by maintenance level on national forests in the 

North Cascadia Adaptation Partnership

Operational maintenance levels Mount Baker- OkanoganSnoqualmie National	 Wenatchee

Code Description Forest National Foresta

Kilometers

ML 0 Decommissioned 504 —a

ML 1 Basic custodial care (closed) 835 4259

ML 2 High clearance cars/trucks 1434 6370

ML 3 Suitable for passenger cars 1706 2042

ML 4 Passenger car (moderate comfort) 129 378

ML 5 Passenger car (high comfort) 74 84

Total All roads 4682 13 133

a

 Okanogan-Wenatchee National Forest missing information on decommissioned roads.
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change (IPCC 2007), and numerous studies have shown that the PNW is sensitive to climate change, and particularly to effects related to loss of snowpack and 

associated changes in hydrologic response and water temperature (e.g., Abbe et al. 

2010, Elsner et al. 2010, Hamlet and Lettenmaier 1999, Mantua et al. 2010, Mote 

and Salathé 2010. By extension, the mountainous national forests and national parks 

in the PNW are expected to be sensitive to climate change. 

Changes in hydrometeorological variables directly or indirectly affect access. 

Direct effects are those that physically alter the operation or integrity of transportation facilities. These include effects related to floods, snow, avalanches, landslides, 

extreme temperatures, and wind. Indirect effects include secondary influences of 

climate shifts on access, such as reduced water supplies, threats to public safety, 

and changes in visitor use patterns. For hydrologic extremes such as flooding, the 

effect on access may appear to be related to weather (e.g., the effects of a single 

storm) rather than climate, but it is the expansion of future extremes outside the 

historical range of frequency or intensity that triggers the greatest impacts (e.g., by 

exceeding current design standards for infrastructure). 

Variation in temperature and precipitation ultimately determine the hydrologic 

behavior of watersheds in the North Cascade Range. Global climate models (GCMs) 

project future changes in temperature and precipitation (IPCC 2007). The model 

projections described here use future temperature and precipitation scenarios based 

on the mean values generated from an ensemble of 10 GCMs and two “bracketing” 

GCMs based on the A1B greenhouse gas emissions scenario (Nakićenović and 

Swart 2000) (see chapter 3). The A1B scenario is a medium-high emissions scenario 

reflecting rapid increases in greenhouse gasses in the early 21st century followed 

by substantial reductions in emissions in the second half of the 21st century, which 

slows the rate of warming. In comparison with the ensemble, one bracketing GCM, 

PCM1, simulates relatively lower annual temperature increases and slightly drier 

conditions in the PNW for the 2040s. The other bracketing GCM, MIROC 3.2, 

simulates relatively higher annual temperature increases and wetter conditions 

(Littell et al. 2011). Based on these projections, PCM1 is a less warm and drier 

model on an annual basis and MIROC3.2 is a warmer and wetter model compared 

to the 10-model ensemble over the PNW on an annual basis. Although PCM1 is a 

cooler model than the ensemble, it projects warmer temperatures than historical 

annual averages. However, during the cool season (October through March), PCM1 

projects the same increase (1.8 °C) in temperature and only slightly drier conditions 

than the ensemble. The MIROC 3.2 model projects a larger increase in temperature 

and precipitation by the 2040s compared to the ensemble. 

Mountain watersheds 

are sensitive to loss 

of snowpack and 

associated changes in 

hydrologic response 

and water temperature.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Projections of temperature and precipitation from these GCMs were applied 

as monthly changes to meteorological data input into the physically-based Variable Infiltration Capacity (VIC) macro-scale hydrologic model (Elsner et al. 2010, 

Liang et al. 1994). In general, the VIC model acts as a translator between changes 

in climate and hydrologic effects on riverflows, snowpack, soil moisture, and other 

ecosystem processes (Elsner et al. 2010, Hamlet et al. 2013, Littell et al 2011, Mote 

and Salathé 2010). The implementation of the VIC model as used for this assessment provides hydrologic information at 1/16th degree resolution (about 5 × 6 km 

or 30 km2 per grid cell). To provide information at the watershed scale, gridded 

model output is aggregated up from the native resolution of the hydrologic model 

to summarize effects for individual watersheds at the 12-digit (6th level) hydrologic 

unit code (HUC) scale delineated by the U.S. Geological Survey. The snowpack 

simulations were produced using a special high-resolution version of the VIC model 

implemented at 800-m resolution.3

Climate Change Effects on Flooding and Extreme Low Flows

Climate change effects in watersheds of the PNW can be broadly characterized by 

mid-winter temperatures and basin type (Hamlet and Lettenmaier 2007). Raindominated basins are above freezing most of the time in winter, and snow accumulation is minimal. Rain-dominated basins typically have one peak in streamflows 

in mid-winter that coincides with peak precipitation. Mixed-rain-and-snow (also 

sometimes called “transient” or “transitional”) basins are typically found at moderate elevations and can collect substantial snowpack in winter (10 to 40 percent of 

October through March precipitation), but are typically only a few degrees below 

freezing on average in mid-winter. Mixed-rain-and-snow basins typically have two 

seasonal streamflow peaks, one in autumn caused by rain, and another in spring 

caused by snowmelt. Colder basins show a larger peak in spring, warmer basins 

a larger peak in fall. Snowmelt-dominated basins are relatively cold in winter and 

capture a relatively large portion (> 40 percent) of their October through March precipitation as snow. Snowmelt-dominated basins typically have relatively low flows 

in winter and one streamflow peak in spring that coincides with spring snowmelt 

(Elsner et al. 2010).

In response to warming, shifts from snowmelt-dominant to mixed-rain-andsnow basins, and from mixed-rain-snow to rain-dominant basins are projected by 

the 2040s in the PNW (Tohver et al. 2013) (fig. 4.2). However, the northern portion

3

 Mauger, G. 2011. Meteorological dataset. Unpublished data. Available online

at: http://cses.washington.edu/picea/mauger/VIC_SNOW/pub/. (30 October 2012).
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of the North Cascades will retain some snow-dominant basins that may create a 

refuge of habitat and hydrologic processes in the PNW. In comparison, rain-dominant basins at lower elevation are projected to have little change in the timing of 

streamflow, and monthly hydrographs will likely remain similar to those simulated 

for historical conditions (Elsner et al. 2010, MacArthur et al. 2012). Mixed-rain-andsnow basins, by comparison, are expected to experience large shifts in the timing 

of high flows from late spring or early summer snowmelt events to late autumn 

and early winter peak flows (Elsner et al. 2010). The coldest snowmelt-dominated 

basins (at the highest elevations in the North Cascades [fig. 4.3]) are expected to 

continue to experience peak flows in spring, but with smaller and earlier peak flows 

by the 2040s.

Flooding regimes in the PNW are sensitive to precipitation intensity, temperature effects on freezing elevation (which determines whether precipitation falls as 

rain or snow), and the effects of temperature and precipitation change on seasonal 

Figure 4.2—Projected shift in watershed basin type in the Pacific Northwest by the 2040s (2030–2059). Basins represent the spatial 

resolution of 10-digit hydrologic unit codes (HUCs), or the 5th-level watershed classification as delineated by the U.S. Geological Survey. 

Basin types are defined by the ratio of April 1 snow water equivalent (SWE) to cool season (October through March) precipitation, which 

represents most precipitation falling as snow or rain. Future projections were modeled using the A1B emission scenario and three model 

configurations, an ensemble of 10 GCMs and two bracketing GCMs (one projecting less warming and drier conditions than the ensemble 

mean [PCM1] and one projecting more warming and wetter conditions than the ensemble mean [MIROC 3.2]). Black box in first plot is 

zoomed in on figure 4.3.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

snow dynamics (Hamlet and Lettenmaier 2007, Tohver 2013). Floods in the PNW 

typically occur during the autumn and winter because of heavy rainfall (sometimes 

combined with melting snow) or in spring because of unusually heavy snowpack 

and rapid snowmelt (Hamlet and Lettenmaier 2007, Sumioka et al. 1998). At small 

spatial scales, summer thunderstorms can also cause local flooding, such as near 

Stehekin (USDI NPS 2012a). 

Climate models estimate little change in annual precipitation in the PNW when 

averaged over multiple models, but the seasonality of precipitation is projected to 

shift towards greater precipitation in autumn, winter, and spring, and less precipitation in summer (MacArthur et al. 2012, Mote and Salathé 2010, Salathé et al. 2010). 

Annual runoff throughout Washington is projected to increase by 2.5 percent by 

the 2040s, and 6.2 percent by the 2080s compared to the period 1970 to 1999. Cool 

season (October through March) runoff is projected to increase even more, up to 

20 percent by the 2040s and 34 percent by the 2080s (Elsner et al. 2010). Over the 

Figure 4.3—Projected shift in watershed basin type in the North Cascades by the 2040s (2030–2059). 

Description of classification and models same as stated in caption for figure 4.2. SWE = snow water 

equivalent.
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Western United States, regional climate models simulate statistically significant 

increases in the intensity of future extreme winter precipitation events (Dominguez 

et al. 2012). Increased autumn and winter precipitation, coupled with warmer temperatures that raise freezing elevations and effectively increase basin area during 

storms, is projected to increase autumn and winter flood risk in the Cascade Range 

(Hamlet and Lettenmaier 2007, Mantua et al. 2010, Tohver et al. 2013). 

Extreme flooding, defined here as the 100-year flood (the annual peak flow 

with a 1 percent probability of being exceeded, or Q100), is projected to increase 

throughout much of the North Cascades. One exception is in the Pasayten Wilderness where peak flows are projected to slightly decrease. The highest increases 

in Q100 are projected for the leeward (sheltered) side of the mountains east of the 

Cascade crest (fig. 4.4), where Q100 is projected to be more than double historical 

levels in some watersheds. Higher runoff in the cool season will also likely cause 

rivers to become more geomorphically dynamic by creating or enlarging channels, 

eroding once stable banks, widening flood plains, and generating additional sediment and debris that can fill channels and cause water level to rise. Box 4.2 

Figure 4.4—Changing trend in the 100-year flood statistic in watersheds of the North Cascades (at the 12-digit, 6th-level hydrologic unit 

code watershed scale delineated by the U.S. Geological Survey). Flood level is designated as the annual peak flow with an estimated 100-

year return frequency (Q100). The flood statistic represents the ratio of Q100 in 2020s, 2040s, and 2080s to historical (1916–2006) Q100. 

Ratios greater than 1 indicate increasing peak flows in the future. Ratios less than 1 indicate decreasing peak flows. 

Extreme flooding is 

projected to increase 

throughout much of 

the North Cascades.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

summarizes projected regional trends in flooding with climate change. These 

effects may be exacerbated by projected increases in winter soil moisture, which 

reduce infiltration capacity of the soil and increase runoff.

Flooding can be exacerbated by rain-on-snow (ROS) events, which are contingent on the magnitude of precipitation, elevation of the freezing line, and existing 

snowpack when storms happen (McCabe et al. 2007). Warming affects future flood 

risk from ROS events differently depending on the importance of these events 

as a driver of flooding in different basins under the current climate. On the west 

slopes of the Cascades, for example, the elevation of the freezing line in winter is 

a key factor. As temperatures warm, the ROS zone will likely move up in elevation. This upward shift in the ROS zone will tend to strongly increase flooding in 

basins where the current ROS zone is low in the basin with a large snow collection 

area above because of the effectively expanded drainage area. Increases in winter 

precipitation exacerbate these effects.

In contrast, in basins in which the ROS zone is higher in the basin, the upward 

shift in the ROS zone will only modestly increase the contributing basin area, and 

flooding will increase less severely and primarily because of increases in winter 

precipitation (Hamlet and Lettenmaier 2007, Tohver et al. 2013). Another important 

factor is the area of the rain-on-snow zone. As the ROS zone moves to higher 

elevation, the zone itself shrinks in size, reducing its potential contribution to runoff 

production. Finally, the probability of ROS events occurring is expected to decrease 

Box 4.2—Summary of projected trends in flooding with

climate change

• The Pacific Northwest is projected to have an increase in flood frequency 

throughout the region.

• Increased flood frequency will differ by season, but autumn is projected to 

experience the largest increase in frequency.

• The timing of peak flows is likely to shift earlier in the water year (October 

through September), but these shifts will vary by basin type (e.g., earlier in 

spring for snow-dominated, spring to autumn for mixed-rain-and-snow, little 

change for rain-dominated).

• Extreme precipitation events are expected to become more frequent, causing 

localized extreme floods.

• Warming may alter rain-on-snow contribution to flooding depending

on the basin and current location of rain-on-snow zone: reductions where 

zones are already high in the basin and increases where zones are currently 

lower in the basin, primarily from the expanded drainage area.
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with warmer temperatures because of decreases in snow occurrence and the length 

of time that snow is on the ground (McCabe et al. 2007). In summary, the incidence 

and importance of ROS events as a direct cause of flooding may decline in the 

future (decreased area of ROS zone and less antecedent snow), but rising freezing 

lines associated with the ROS zone moving up slope tends to increase flood risk by 

increasing the contributing basin area during storms.

The trend in extreme low flows, defined here as the lowest annual 7-day average flow with a recurrence interval of 10 years (7Q10), is generally opposite of peak 

flow projections because of reduced snowpack and warmer and drier summers. The 

west slopes of the Cascade Range are projected to experience substantial declines in 

low flows by the 2080s compared to historical levels (fig. 4.5). The 7Q10 values on 

the east slopes of the Cascade Range do not decrease as much as on the west, and 

a few watersheds in the northeast are projected to have increased low flows over 

historical levels, presumably because of enhanced sensitivity to increased precipitation. The generally reduced sensitivity of low flows on the east slopes is probably 

because simulated soil moistures are already at very low levels in late summer for 

Figure 4.5—Changing trend in the low-flow statistic in watersheds of the North Cascades. Low flow is designated as the 7-day average 

flow with a recurrence interval of 10 years (7Q10) expressed as a ratio of 7Q10 in 2020s, 2040s, and 2080s to historical (1916–2006) 

7Q10. Ratios greater than 1 indicate increased low flows. Ratios less than 1 indicate decreased low flows (i.e., lower low flows). Roads 

and trails are also shown. Future projections were modeled using the A1B emission scenario and downscaled climate data derived from 

10 global climate models (Hamlet et al. 2013).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

the current climate, so further increases in drought have relatively little effect on 

baseflows (Hamlet et al. 2013). 

Climate Change Effects on Snow Cover

One common measure of snowpack is snow water equivalent (SWE), which 

represents the liquid water content of the snowpack. For temporal and spatial 

comparisons, SWE on April 1 is commonly used because it corresponds to the date 

of peak SWE in many areas and is correlated with summer water supply in the 

PNW. April 1 SWE has declined over the 20th century, although decadal climatic 

variability also affects SWE on shorter time scales (Hamlet et al. 2005, Mote et 

al. 2008). In near-coastal areas, SWE is more sensitive to warming in winter and 

spring, whereas SWE in inland areas is more sensitive to precipitation in winter 

and warming in spring (Hamlet et al. 2005). Snowpack in the North Cascades was 

modeled at a resolution of 30 arc-seconds of latitude and longitude (about 800 m), 

a finer resolution than other hydroclimatic variables discussed in this chapter (see 

footnote 2). Finer resolution allows for more detailed projections of snow across a 

topographically complex landscape that are useful for comparing spatial patterns of 

snow with locations of roads and trails. 

These fine-scale projections of April 1 SWE indicate substantial decreases by 

the 2040s compared to historical levels (fig. 4.6). These projections are supported 

by other studies that report average reductions in April 1 SWE of 46 percent by the 

2040s in Washington (Elsner et al. 2010). Reductions in SWE are largest in warmer 

areas west of the Cascade crest and at low elevations in eastern Washington. Higher 

elevations will continue to retain snow cover in early summer. Approximately a 

third of the NCAP area is projected to experience little (±10 percent) change from 

historical patterns and these areas have a mean elevation of 1740 m, but extend as 

low as 671 m. The northeast corner of the area (Pasayten Wilderness) may experience slight increases in April 1 SWE because of persistent cold temperatures and 

increasing precipitation. The date when 90 percent of winter snow melts is projected to be earlier than historical dates, particularly west of the Cascade crest and 

at the lowest elevations (fig. 4.7). Differences between east and west slopes of the 

Cascades reflect the influence of a warmer maritime climate to the west and a more 

continental climate to the east. 

Effects of Changing Soil Moisture and Landslides

Landslides, which are the movement of a mass of rock, earth, or debris down a 

slope (Cruden 1991), are a product of their environment and they also influence 

the environment (Crozier 1986). Antecedent rainfall or snowmelt (reflecting soil 

Projected reductions in 

snow water equivalent 

are largest west of the 

Cascade crest and 

at low elevations in 

eastern Washington.
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Figure 4.6—April 1 SWE in the North Cascades in the 2040s (2030–2059) shown as a percentage 

change from historical levels (1916–2006), calculated as ([future - historical] / historical) × 100. 

Percentage change indicates the difference between future projections and historical levels. Future 

projections were modeled using the A1B emission scenario and three model configurations, an 

ensemble of 10 GCMs and two bracketing GCMs (one projecting less warming and drier conditions 

than the ensemble mean [PCM1] and one projecting more warming and wetter conditions than the 

ensemble mean [MIROC 3.2]). Data are resolved at 30 arc-sec (about 800 m) resolution 

(see footnote 3).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

moisture), ground-water, and ground movement rates are controls of landslides. 

Heavy winter rainfall and excess ground-water increase landslides (Brooks et al. 

2004, Crozier 2010, Moore et al. 2010). Water in soil reduces soil shear strength, 

and increases shear stress, leading to slippage if the shear stress in the soil exceeds 

the shear strength. Most landslides, including debris flows and torrents, are initiated 

during intense rain events or during less intense events preceded by persistent rain 

over a prolonged period (high antecedent soil moisture), rapid snow or ice melt, or 

low evaporation conditions that increases soil moisture (Baum et al. 1998, Brooks et 

al. 2004, Crozier 1986).

Figure 4.7—Average change in date at which 90 percent of the snow water equivalent is melted for 

the 2040s (2030–2059) compared to historical dates (1916–2006). Change indicates the difference 

in number of days between future projections and historical levels. Future projections were modeled 

using the A1B emission scenario and three model configurations, an ensemble of 10 GCMs and two 

bracketing GCMs (one projecting less warming and drier conditions than the ensemble mean [PCM1] 

and one projecting more warming and wetter conditions than the ensemble mean [MIROC 3.2]). Data 

are resolved at 30 arc-sec (about 800 m) resolution. (see footnote 3). 
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Most landslides in the PNW occur during the rainy season between October 

and May (Baum et al. 2007), and hundreds of slides may occur in the region during 

an intense storm (Chatwin et al. 1994). For example, the Washington Department of 

Natural Resources (WDNR) documented more than 500 slides from a January 2009 

storm event (WDNR 2012). In Washington, landslides are more common in areas 

where average December precipitation is higher than 15 cm, which is primarily 

west of the Cascade crest (MacArthur et al. 2012), although landslides are common 

in the southeastern part of the NCAP area as well (fig. 4.8). The steep topography 

Figure 4.8—Inventoried historical landslides (i.e., mass wasting events) in the North Cascades, 

1940–2005. Inventoried landslides include block fall or topple, debris flow, debris slide or avalanche, 

deep-seated, hyperconcentrated flow, shallow undifferentiated, and unknown type. (Data from the 

State of Washington, Department of Natural Resources; Mount Rainier National Park; and North 

Cascades National Park Complex.)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

and intense precipitation, especially in winter, make the PNW particularly susceptible to slope stability failures and landslides. Landslides also occur frequently after 

rapid snowmelt, particularly ROS events in the transient snow zone (Harp et al. 

1997, Wu and Merry 1990). 

Landslides can increase the resistance of the slope to future slides in the immediate area by removing material vulnerable to sliding (Glade and Crozier 2005, 

Schuster and Highland 2003). However, many landslides occur in approximately the 

same areas and with the same relative abundance as they did previously (Baum et 

al. 1998, Crozier 2010). This suggests that mapping previous slide areas is a potentially useful tool for predicting future risks. More than 6,500 historical landslides 

within the NCAP region have been mapped (fig. 4.8). 

Landslides have long been a phenomenon in western Washington, including 

in recent years (Baum et al. 1998, Sarikhan et al. 2008), and projected changes in 

soil moisture and precipitation form and intensity with climate change may expand 

landslides in the PNW. Recent slides have closed roads and trails for months, years, 

or indefinitely, costing millions of dollars for cleanup and repair. Climate projections indicate that the conditions that trigger landslides will increase because (1) 

more precipitation will fall as rain rather than snow, and (2) more winter precipitation will occur in intense storms. These effects will likely differ with elevation 

because higher elevation areas typically have steeper slopes and more precipitation 

during storms. Furthermore, reduced snowpack is expected to increase antecedent soil moisture in winter (Hamlet et al. 2013). Increasing trends in April 1 soil 

moisture have been observed in modeling studies as a result of warming, showing 

that soil moisture recharge is occurring earlier in spring and is now higher on April 

1 than it was prior to 1947 (Hamlet et al. 2007). 

Elevated soil moisture (and rapid changes in soil moisture or both) can affect 

the stability of a slope and are responsible for triggering more landslides than any 

other factor (Crozier 1986). Antecedent moisture is a good predictor of landslides 

(Kim et al. 1991), so areas with projected increases in antecedent soil moisture 

(coupled with more intense winter storms) support the hypothesis of increasing 

landslide risk. Thus, although VIC does not directly simulate slope stability failures 

or landslides, projections of December 1 total column soil moisture from VIC 

can be used as an indicator of landslide risk. Higher December 1 soil moisture is 

projected for the 2040s throughout the North Cascades but particularly at higher 

elevations and in the east central area (fig. 4.9), suggesting that these areas may 

become more vulnerable to landslides in winter. The most intense storms west of 

the Cascades in the PNW typically arrive in late November or early December. 

Conditions that 

trigger landslides will 

increase because more 

precipitation will fall as 

rain rather than snow.
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Higher soil moisture on December 1 is driven by warmer temperatures in November, which increase the amount of precipitation that falls as rain rather than snow 

causing soil moisture recharge for a longer period in late autumn before significant 

snow accumulation. 

Sensitive Traits of Roads and Trails in the 

North Cascades

To assess vulnerability of access in the national forests and parks in the NCAP, we 

began by identifying the changes in climate to which the system will be exposed 

(see above). Next, we assessed the traits of the transportation system that may be 

sensitive to projected climate changes (box 4.3). These traits include the location, 

design, and current condition of road and trail infrastructure, as well as recreation 

Figure 4.9—Percentage of change in total soil moisture content on December 1 in the North Cascades for the 2040s (2030–2059) compared to historical levels (1916–2006), calculated as ([future/

historical] / historical) × 100. Future projections were modeled using the A1B emission scenario and 

three model configurations, an ensemble of 10 GCMs and two bracketing GCMs (one projecting less 

warming and drier conditions than the ensemble mean [PCM1] and one projecting more warming 

and wetter conditions than the ensemble mean [MIROC 3.2]).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

use and demand. This vulnerability assessment of access can inform transportation 

management and long-range planning. The section below describes the sensitive 

traits of the transportation system in the NCAP area.

Aging Infrastructure

Many roads and trails were built decades ago, creating sensitivities in the infrastructure because of age. Many infrastructure components are near the end of their 

design lifespan. For example, culverts typically have a design lifespan of 25 to 75 

years, depending on design and material. Culverts remaining after this time have a 

higher likelihood of structural failure and are less resilient to high streamflows and 

bed load movement. Aging infrastructure that continues to deteriorate exacerbates 

sensitivity. As roads and trails age, their surface and subsurface structure weakens. 

Box 4.3—Summary of sensitivities of the U.S. Forest 

Service and National Park Service transportation system 

in the North Cascades

• Aging and deteriorating infrastructure exacerbates sensitivity to climate 

impacts, and outdated designs of existing infrastructure decrease resilience 

to new threats.

• Inadequate maintenance and inspection (e.g., clearing of debris from culverts) with limited funding increases the susceptibility to failures in structure and function.

• Abundant roads and trails built on steep topography are more sensitive to 

landslides and washouts.

• A substantial portion of the transportation system is at high elevation, which 

increases exposure to weather extremes and increases the costs of repairs 

and maintenance.

• Many roads were built across or adjacent to waterways, creating sensitivity 

to high streamflows, stream migration, and sediment movement.

• Limited road redundancy in primary travel corridors, especially in the 

national parks, increases the likelihood of operational disruptions from 

climate-related events.

• Multiple management agencies retain jurisdiction over transportation routes, 

and different management approaches and priorities may create conflicting 

objectives.

• Funding constraints, insufficient funds, or both limit the ability of agencies 

to repair damaged infrastructure or take preemptive actions to create a more 

robust system.

• Design standards or operational objectives that are unsustainable in a new 

climate regime may increase the frequency of infrastructure failure in the 

future.
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Consequently, a less-intense storm can cause more damage than a storm of high 

intensity would have caused when the infrastructure was relatively new.

Design and Use Considerations

Advanced design of materials, alignment, drainage, and subgrade that are required 

standards today were generally not available when much of the travel network was 

built in the North Cascades. Consequently, new or replaced infrastructure is likely 

to be less sensitive to climate change, especially if climate change is considered 

in the design. New culverts and bridges are often wider than historical structures 

to meet hydraulic regulations or current design standards. For example, recent 

improvements to the ferry landing at Stehekin in the eastern portion of NOCA 

allow access during rapid fluctuations in lake level caused by extreme rain and 

snow events (USDI NPS 2010b) because the landing was designed to function 

within a wider range of hydrologic conditions. Although climate change was not 

the primary motivation for these design changes, the improvements will likely also 

reduce climate change vulnerability. 

Some travel ways, particularly roads on the national forests, were designed for 

temporary use, which can make them more susceptible to deterioration or damage 

with sustained use. Many roads and trails on the forests were originally built for 

uses other than recreation, such as accessing facilities or natural resources, but 

in recent decades, recreation has increased trail use. Because of these different 

intended uses, roads and trails were originally constructed to different standards 

and the effects of design and use on vegetation and aquatic habitat were considered 

less than they are today. 

A lack of redundancy in a transportation system can cause operational sensitivity when damage disconnects the system. The transportation system within the 

NCAP area, particularly in national parks, lacks redundancy, increasing its sensitivity to climate change. Wilderness designations, which exclude roads, preclude 

some redundancy, as does the potential for unacceptable impacts to ecosystems. 

Many roads and trails, especially at high elevation, provide sole access to recreation 

areas, making the network sensitive to disrupted operation if damaged by storms or 

landslides. The loss of a segment of trail or road can leave large areas inaccessible 

for long periods depending on the extent of damage and availability of resources for 

repair. Thus, tradeoffs exist between redundancy in the transportation system and 

objectives to limit roads and associated impacts and maintenance costs.

Location and Land Use

The location of roads and trails can increase vulnerability to climate change. Many 

roads and trails were built on steep slopes because of the rugged topography of the 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

region, so cut slopes and side-cast material have created landslide hazards. Timber 

harvesting and its associated road network on national forests have contributed to 

the sensitivity of existing infrastructure by increasing storm runoff and peak flows 

that can affect road crossing structures (Croke and Hairsine 2006, Schmidt et al. 

2001, Swanston 1971). High-elevation terrain further challenges transportation 

management because of snow, ice, and glacial outwash. The transportation system 

in the North Cascades is affected by abundant streams and rivers, near and across 

which roads and trails were often built, making these locations sensitive to changes 

in streamflow and stream channels (e.g., channel migration in the floodplain). Most 

stream crossings have culverts rather than bridges, and culverts are built to lower 

standards than bridges, making the number of culverts a major factor in sensitivity 

to increasing flood risk. Many roads and trails were constructed in gently sloped 

areas next to streams, but this cost-saving design has created sensitivity to flooding, channel migration, bank erosion, or shifts in alluvial fans and debris cones. 

Some roads and trails were constructed in abandoned stream channels (e.g., part of 

Carbon River Road at MORA and part of Colonial Campground Road at NOCA), 

which have subsequently become reactivated during floods, causing major damage.

Maintenance and Management of Roads and Trails

Management of roads and trails (planning, funding, maintenance, response) differs 

by agency and can affect the overall sensitivity of the transportation system. The 

management priority of one road or trail segment can affect the function of the connected segments, which can be challenging when the segments are under different 

jurisdictions. Major highways within the North Cascades, built to higher design 

standards and maintained more frequently, will likely be less sensitive to climate 

change. For example, the major highways through the NCAP are managed by the 

Washington Department of Transportation and are vital transportation corridors. 

Consequently, these highways are built to sustain heavy traffic loads and extreme 

mountainous climate and are inspected and maintained frequently (WSDOT 2011). 

For similar reasons, most roads and bridges in the Washington highway system 

are likely more resilient to climate change than their unpaved counterparts built to 

lower design standards in the national forests and parks.

A lack of funding can limit options for repairing infrastructure, which can 

affect the short- and long-term vulnerability of the transportation system. For 

example, replacing a damaged culvert with an “in-kind” culvert that was undersized 

for the current streamflow conditions leads to continued sensitivity to both the current flow regime and projected higher flows. Limited funds because of diminishing 

timber revenue on national forests in the past 20 years have decreased funding for 
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adequate maintenance to sustain the full transportation network. Thus, the MBSNF 

and OWNF have a backlog of maintenance and upgrades to meet current objectives.

Current and Short-Term Climate Exposures to Access 

in the North Cascades

Assessing the vulnerability of the transportation network to changes in climate 

requires evaluating projected changes in hydrologic processes and exposure of the 

transportation system to these processes. The integrity and operation of the transportation network in the North Cascades may be affected in several ways (fig. 4.10). 

Figure 4.10—Climate-related exposures to access in the North Cascades. These exposures can affect both the operation and integrity of 

the transportation system over short or long time periods.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

When integrating this assessment into agency planning, it may be useful to consider 

the magnitude of projected changes in climate and system responses in three timeframes: current to short term (less than 10 years), medium term (10 to 30 years), and 

long term (30 to 100 years) (box 4.4).

Changes in climate have already altered hydrologic regimes in the PNW, 

including decreased snowpack, higher winter streamflow, earlier spring snowmelt, 

earlier peak spring streamflow, and lower low streamflow in summer (Hamlet et 

al. 2007, 2010). Damage to infrastructure is likely to be related primarily to factors such as aging infrastructure and mismatches between existing infrastructure 

designs and the current climate (which reflects cumulative 20th-century trends). 

Ongoing changes in climate and hydrologic response in the short term are likely 

to be a complex mix of natural variability combined with ongoing trends related 

to climate change. High variability of short-term trends is an expected part of the 

response of the evolving climate system. Natural climatic variability, in the shortterm, may exacerbate, compensate for, or even temporarily reverse expected trends 

in some hydroclimatic variables. For example, in the last 5 years, a series of unusually cool and wet springs have resulted in high spring snowpack in the Cascades, 

despite continued expectation of declining spring snowpack trends at longer time 

scales. 

Higher streamflow in winter (October through March), in comparison to 

historical conditions, increase the risk of flooding and impacts to structures, roads, 

and trails. Many transportation professionals consider flooding and inundation to 

be the greatest threat to infrastructure and operations because of the damage that 

standing and flowing water cause to transportation structures (MacArthur et al. 

2012, Walker et al. 2011). Floods also transport logs and sediment that block culverts or are deposited on bridge abutments. Isolated intense storms can overwhelm 

the vegetation and soil water holding capacity and concentrate high-velocity flows 

into channels that erode soils and remove vegetation. During floods, roads and 

trails can become preferential paths for floodwaters, reducing operational function and potentially damaging infrastructure not designed to withstand inundation 

(fig. 4.11). For example, intensified flooding and erosion within the lower Stehekin 

Valley during the past 15 years has impeded travel by damaging roads and facilities 

(USDI NPS 2012a). 

Glacial recession attributed to warming (Granshaw and Fountain 2006, Pelto 

and Riedel 2001) has already affected transportation systems in the Cascade Range 

(Beason and Kennard 2007, Walder and Driedger 1994). Receding glaciers leave 

behind unconsolidated material in steep terrain, which become mobile with precipitation and melt water from glaciers (Huggel 2009). With heavy precipitation, this 

Higher streamflow in 

winter will increase the 

risk of flooding and 

impacts to structures, 

roads, and trails.
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Box 4.4—Exposure of access to climate change in the 

North Cascades

Current and short-term exposures (less than 10 years)—

• Roads and trails are damaged by floods and inundation because of mismatches between existing designs and current flow regimes.

• Landslides, debris torrents, and sediment and debris movement block access 

routes and damage infrastructure.

• Traffic is affected by temporary closures to clean and repair damaged roads 

and trails.

• Frequent repairs and maintenance from damages and disruption incur higher 

costs and resource demands.

Medium-term exposures (intensifying or emerging in approximately 

10 to 30 years)—

• Flood and landslide damage will likely increase in late autumn and early 

winter, especially east of the Cascade crest and in mixed-rain-and-snow 

watersheds. 

• Current drainage capacities may become overwhelmed by additional water 

and debris.

• Increases in surface material erosion are expected.

• Backlogged repairs and maintenance needs will grow with increasing 

damages.

• Demand for travel accommodations, such as easily accessible roads and 

trails, is projected to increase, which could increase travel management costs.

• Increased road damage will challenge emergency response units, making 

emergency planning more difficult.

Long-term exposures (emerging in 30 to 100 years)—

• Fall and winter storms are expected to intensify, greatly increasing flood 

risk and infrastructure damage and creating a greater need for cool-season 

repairs.

• Higher streamflows will expand channel migration, potentially beyond recent 

footprints, causing more bank erosion, debris flows, and wood and sediment 

transport into streams.

• Lower low streamflows associated with declining snowpack are projected.

• Changes in hydrologic response may affect visitation patterns by shifting the 

seasonality of use. 

• Shifts in the seasonality of visitation may cause additional challenges to visitor safety, such as increased use in areas and during seasons prone to floods 

and avalanches.

• Travel management will be challenged to provide adequate flexibility to 

respond to uncertainty in impacts to access.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

material can transform into debris flows that pull in additional material. Deposition of sediment downstream leads to aggradation (rising of the riverbed level) and 

avulsion (change in river course) of streams and rivers. These phenomena were 

observed along the Nisqually River in the southwest part of MORA in the extreme 

flood of November 2006, for example. In MORA, aggradation has caused sections 

of rivers held back by levees to be a meter or more above adjacent roads, increasing flood risk and damage to roads when levees fail (Abbe et al. 2010, Beason and 

Kennard 2007). 

Erosion, mudflows, and landslides caused by intense and persistent rainfall or 

flooding have become an increasingly common cause of damage to roads and trails, 

disrupting operations in the North Cascades (fig. 4.12) (MacArthur et al. 2012). 

For example, a recent landslide at Ross Lake destroyed private and public facilities 

and cut off sole access to the Ross Dam powerhouse and dam by covering the Ross 

Dam haul road (USDI NPS 2012c). An intense storm in November 2006 triggered 

numerous landslides in MORA and contributed, along with flood damage, to a 

6-month closure of the park (fig. 4.12). Regional storms such as this can overwhelm 

response personnel, prolonging delays in reestablishing access after landslides. 

Landslide risk also increases with timber harvesting on steep terrain because tree 

removal decreases root cohesion in the soil and increases soil moisture because of 

more snow accumulation and less evapotranspiration (Istanbulluoglu et al. 2004, 

Montgomery et al. 2000, Schmidt et al. 2001). 

Figure 4.11—Storm damage in Mount Rainier National Park, November 2006: (A) Highway 123, and (B) the Carbon 

River Road. Damage to transportation infrastructure can also affect utilities located within the roadway prism. Mount Rainier National Park

Mount Rainier National Park

A B
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Emerging or Intensifying Exposure in the Short Term

Several exposures to climate change are emerging or may be increasingly expressed 

in the short term (less than 10 years). Warmer temperatures and increasing precipitation have increased flood risk in the Cascades in the last 40 years (Hamlet and 

Lettenmaier 2007). In the short term, increased flooding of roads and trails will 

likely continue and possibly even intensify, threatening the structural stability of 

crossing structures and subgrade material. Observed increases in high flows and 

A

Mount Rainier National Park Mount Baker-Snoqualmie National Forest

Figure 4.12—(A) Storm-triggered landslide covering Stevens 

Canyon road in Mount Rainier National Park, November 

2006, and (B) slump along White Chuck trail in Mt. BakerSnoqualmie National Forest damaged during a storm, 

October 2003. The trail switchbacks through the eroded area. 

B
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

winter soil moisture may also increase the amount of large woody debris delivered 

to streams, further increasing damage to culverts and bridges, and in some cases 

making roads impassable or requiring road and facility closures. More intense 

precipitation can also reduce visibility and increase hazardous conditions. Unpaved 

roads with limited drainage facilities or minimal maintenance are likely to experience increased surface erosion, requiring additional repairs or grading. 

Increasing incidence of more intense precipitation and higher soil moisture in 

autumn or early winter could increase the risk of landslides. Landslides can also 

contribute to flooding by diverting water, blocking drainage, and filling channels with debris (Chatwin et al. 1994, Crozier 1986, Schuster and Highland 2003). 

Culverts filled with landslide debris can cause flooding, damage, or complete 

destruction of roads and trails (Halofsky et al. 2011). Landslides that connect with 

waterways or converging drainages can transform into more destructive flows 

(Baum et al. 2007). Roads themselves also increase landslide risk (Swanson and 

Dyrness 1975, Swanston 1971). In the Western United States, the development of 

roads increased the rate of debris avalanche erosion by 25 to 340 times the rate 

found in forested areas without roads (Swanston 1976), and Chatwin et al. (1994) 

and Montgomery (1994) showed that the number of landslides is directly correlated 

with total kilometers of roads in an area. Consequently, areas with high road or trail 

density and projected increases in soil moisture that already experience frequent 

landslides may be most vulnerable to increased landslide risks (fig. 4.13). 

Short-term exposures to changes in climate are likely to affect safe access in 

the North Cascades. Damaged or closed roads reduce agency capacity to respond to 

emergencies or provide detour routes during emergencies. Increased flood risk in 

autumn could make conditions more hazardous for river recreation. More wildfires 

(see chapter 5) could reduce safe operation of some roads and require additional 

emergency response to protect recreationists and communities. For example, the 

Domke Lake Fire of 2007 threatened to cut off the sole access road to Holden 

Village in the OWNF. Furthermore, damaged and closed roads can reduce agency 

capacity to respond to wildfires. 

Emerging or Intensifying Exposure in the Medium and 

Long Term

Many of the observed exposures to climate change in the short term are likely to 

expand in the medium and long term. In the medium term, natural climatic variability may continue to substantially affect outcomes in any given decade, whereas 

Areas with high road 

and trail density may 

be most vulnerable to 

increased landslide 

risks.
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in the long term, the cumulative impacts of climate change may become the dominant factor, particularly for temperature-related effects. Although uncertainty and 

decadal variability are important considerations, a long-term perspective can be 

useful when planning for climate change, because even as regulation and technology reduce emissions of greenhouse gases, warming will continue for decades 

because of the long residence time of some greenhouse gases in the atmosphere and 

positive climatic feedback mechanisms. Thus, conditions thought to be extreme 

today may be averages in the future, particularly for temperature-related changes 

(MacArthur et al. 2012).

Flooding in autumn and early winter is projected to continue to intensify in the 

medium and long term, particularly in mixed-rain-and-snow basins, but direct ROS 

events may diminish in importance as a cause of flooding (McCabe et al. 2007). 

At mid to high elevations, more precipitation falling as rain rather than snow will 

continue to increase winter streamflow. By the 2080s, peak flows are anticipated to 

increase substantially in magnitude and frequency, especially east of the Cascade 

crest (fig. 4.4). Throughout the NCAP area, mixed-rain-and-snow watersheds will 

Figure 4.13—An area on the eastern slope of the Cascade Range near Leavenworth, Washington, with more than a 10 percent 

increase (shown in blue-green) in December 1 total soil moisture projected for the 2040s (2030–2059). This area is shown 

with known historical landslides. Areas with increases in December 1 total soil moisture may have higher risk of landslides, 

suggesting locations to prioritize for drainage improvements, rerouting, and road decommissioning. These are also areas where 

wetter soils may require shifts in trail and road surface and subgrade design and maintenance. 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

increasingly behave as rain-dominated watersheds (Littell et al. 2011, Tohver et al. 

2013). In the long term, higher and more frequent peak flows will likely continue to 

increase sediment and debris transport within waterways, particularly downstream 

of receding glaciers (see footnote 3). These elevated peak flows, along with landslide sediment contributions, will affect stream-crossing structures downstream as 

well as adjacent structures inundated because of elevated stream channels. Even as 

crossing structures are replaced with wider and taller structures, shifting channel 

dynamics caused by changes in flow and sediment may affect lower elevation segments adjacent to crossings, such as bridge approaches. 

The risk to roads and trails from projected increases in Q100 is apparent when 

viewing a single watershed where Q100 is projected to more than double by the 

2080s (fig. 4.14). In the Tillicum Creek watershed, many roads were built adjacent 

to and across streams, contributing to their vulnerability. Areas with high road 

density, such as near Leavenworth, Washington, and northeast of MORA, may be 

particularly vulnerable to increasing flood risk and channel migration in the long 

term.

Projected increases in flooding in autumn and early winter will challenge 

maintenance and repair operations, and shifts in the timing of peak flows will 

affect the timing of maintenance and repair of roads and trails. More repairs may be 

necessary during the cool, wet, and dark time of year in response to damage from 

autumn flooding and landslides, challenging crews to complete necessary repairs 

before snowfall. If increased demand for repairs cannot be met, access may be 

restricted until conditions are more suitable for construction and repairs. 

Larger declines in low streamflow in summer in the long term, especially west 

of the Cascade crest (fig. 4.5), may require increased use of more expensive culverts 

and bridges designed to balance the management of peak flows with providing 

low flow channels in fish-bearing streams. Design regulations for aquatic habitat 

will become more difficult to meet as warming temperatures hinder recovery of 

cold-water fish populations, although some streams may be buffered by inputs from 

glacial melt or ground water in the medium term.4

Over the long term, increasing winter precipitation and higher winter soil 

moisture are expected to increase the risk of landslides in early autumn and winter. 

Landslide risk may increase more in areas with more tree mortality from fire and 

insect outbreaks because tree mortality reduces soil root cohesion and decreases

4 Reidel, J.L. 2011. Personal communication. Geologist, National Park Service, North 

Cascades National Park Complex, 810 Star Route 20, Sedro-Woolley, WA 98284.

Projected increases in 

flooding will challenge

maintenance and repair 

operations.
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interception and evaporation, further increasing soil moisture (Martin 2006, Montgomery et al. 2000, Neary et al. 2005, Schmidt et al. 2001). Thus, soils will likely 

become more saturated and vulnerable to slippage on steep slopes during the wet 

season. Although floods and landslides will continue to happen near known hazard 

areas (e.g., because of high forest road density), they may also happen in new areas 

(e.g., those areas which are currently covered by deep snowpack in mid-winter) 

(MacArthur et al. 2012). Thus, more landslides at increasingly higher elevations 

may be a long-term effect of climate change.

Coinciding exposures in space and time may be particularly detrimental to 

access. Increases in peak flows and soil moisture in mixed-rain-and-snow basins 

are likely to create dynamic stream channels and unstable soils that will challenge 

efforts to maintain infrastructure and facilities in place. For example, a large portion of the central region of the OWNF with many roads and trails in mixed-rainand-snow watersheds is projected to have more than 50 percent increase in peak 

flows and greater than 10 percent increases in soil moisture by the 2040s (fig. 4.15). 

Figure 4.14—Roads and streams in the Tillicum Creek watershed in eastern Washington where the magnitude of the 100-year 

flood (Q100) is expected to more than double by 2080s. In this 57-km2 watershed there are 77 km of roads and trails and 320 km 

of streams that intersect at 984 locations, likely requiring numerous stream crossing structures. Many roads are also adjacent to 

the streams, which may create vulnerabilities to stream migration.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Changes in climate may reduce summer water supply because of reduced 

snowpack and higher evapotranspiration in summer. In remote areas in the national 

parks, water is often supplied from local sources rather than brought in from commercial water suppliers. For example, the Sunrise visitor center and ranger station 

in MORA are supplied by water from Frozen Lake, which is fed primarily by 

melting snow and ice in late spring. Reduced snowpack and warmer temperatures 

Figure 4.15—Coinciding exposures in mixed-rain-and-snow watersheds within the North 

Cascadia Adaptation Partnership administrative units. Exposures include Q100 flows representing more than a 50 percent increase over historical levels and soil moisture increase of 

more than 10 percent over historical levels by 2040s. Red locations indicate where both these 

exposures coincide within mixed-rain-and-snow basins. 
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will reduce summer water availability, although the effects of warming on glacial 

melt are uncertain. Demand for these locally sourced water supplies may increase 

as the snow-free season lengthens, enabling a longer season of visitor use. Changes 

in the amount and timing of stream runoff could affect lake levels and reservoir 

operations, affecting docks and ramps used by visitors and for delivery of supplies, 

particularly in late summer.

Climate change effects on access may create public safety concerns for the 

USDA FS and NPS. A longer snow-free season may extend visitor use in early 

spring and late autumn at higher elevations (Rice et al. 2012). Lower snowpack may 

lead to fewer snow-related road closures for a greater portion of the year, allowing 

visitors to reach trails and camps earlier in the season. However, warmer temperatures and earlier snowmelt may encourage use of trails and roads before they are 

cleared. Trailheads, which start at lower elevations, may be snow-free earlier, but 

hazards associated with melting snow bridges, avalanche chutes, or frozen snowfields in shaded areas may persist at higher elevations along trails. Relatively rapid 

warming at the end of the 20th century coincided with greater variability in cool 

season precipitation and increased flooding (Hamlet and Lettenmaier 2007). If this 

pattern continues, early-season visitors may be exposed to more extreme weather 

than they have encountered historically, creating potential risks to visitors. In summer, white water rafters may encounter unfavorable conditions from lower streamflows in late summer (Mickelson 2009) and hazards associated with deposited 

sediment and woody debris from higher winter flows. Warmer winters may shift 

river recreation to times of year when risks of extreme weather and flooding are 

higher. These activities may also increase use of unpaved roads in the wet season, 

which can increase damage and associated maintenance costs.

Despite the adverse effects of climate change, climate change may also 

benefit access and transportation operations in the North Cascades over the long 

term. Lower snow cover will reduce the need for and cost of snow removal. The 

earlier snow-free date projected for the 2040s (fig. 4.7) suggests that low- and 

mid-elevation areas will be accessible earlier, especially west of the Cascade crest. 

Earlier access to roads and trails will create opportunities for earlier seasonal 

maintenance and recreation (fig. 4.16). Temporary trail bridges installed across 

rivers may be installed earlier in spring as spring flows decline. A longer snow-free 

season and warmer temperatures may allow for a longer construction season at 

higher elevations. Less snow may increase access for summer recreation, but it may 

reduce opportunities for winter recreation particularly at low and moderate elevations (Joyce et al. 2001, Morris and Walls 2009). The northern portion of the North 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Cascades may retain relatively more snow and glaciers than other areas of the PNW, 

which may create higher localized demand for winter recreation and river rafting in 

summer over the next several decades (see footnote 3). 

The exposures described above are associated with changes in the hydrologic 

regimes. Additional changes in climate associated with extreme temperatures, 

wind, and ecological disturbances are also likely to affect transportation and access 

in the PNW (box 4.5). 

Infrastructure and Travel Management in the North 

Cascades

Road and Trail Operations and Maintenance

Many roads in the North Cascades were not built with the intention that they would 

be permanent, so they were not constructed to design standards promoting longevity. Many culverts were designed to withstand only a 25-year flood. Sections of 

park roads were not built to original design plans (e.g., for drainage) because of 

inadequate funding (Louter 2006). The condition of trails differs widely from excellent to needing total reconstruction. Substantial repairs are still needed for MBSNF 

trails damaged in the floods of 2003 and 2006. These events created an estimated 

Figure 4.16—National forest areas where snow is projected to melt out at least 3 weeks earlier by the 2040s (red color). Some 

roads and trails may be partially or completely snow-free weeks earlier than the historical mean (1916–2006), providing earlier 

access for visitors and maintenance crews.
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$3.5 million maintenance backlog, which limits agency capacity to respond to 

issues of safety and climate change (USDA FS 2011b). Recreational groups, with 

whom the national forests and national parks have partnerships, provide volunteer 

trail crews and advocate for political support and additional funding. Contributions 

of funding and volunteer time from recreational user groups have offset shortfalls 

in the agency capacity to maintain infrastructure for recreation. 

Travel management on the national forests and national parks in the NCAP 

is complicated by funding mechanisms, multiple jurisdictions, interdependence, 

competing demands, steep terrain, abundant streams and lakes, and numerous 

stakeholders. The Washington Department of Transportation (WSDOT) is responsible for operations and maintenance of highways and interstate highways (560 km), 

Box 4.5—Nonhydrologic exposures to travel management 

associated with climate change

Extreme temperatures—

• Extreme high temperatures heat pavement exposed to direct sun, and

softened pavement leads to rutting and decreases the life expectancy and 

integrity of roads (TRB 2008).

• Extreme high temperatures dry the surface of dirt roads causing increased 

dust, which reduces driver visibility.

• Extreme cold temperatures lead to ice forming on roads and bridges, reducing safety for travelers, but this may be mitigated by increased temperatures.

Wind—

• Wind storms can cause trees to fall across roads and trails, hampering travel, 

especially when soils are saturated. Projected increases in winter soil moisture may increase windthrow risks.

• Wind generates dust and transports smoke, which can disrupt safe travel.

Disturbances—

• Tree mortality caused by increasing fire and insect disturbances (see

chapter 5) can have subsequent effects by increasing erosion and landslides.

• Loss of forest cover increases streamflows through loss of 

evapotranspiration.

• Large woody debris can be transported by wind and landslides into streams, 

contributing to channel migration or direct damage to stream-crossing 

structures.

• Fire and smoke reduce the usability of roads and trails, sometimes forcing 

closures.

• Fires can directly consume infrastructure such as bridges, guardrails, and 

signs.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

but within the federal lands, the USDA FS and NPS are generally responsible for 

signs, hazard tree removal outside the road prism, vista clearing, and litter removal. 

Road maintenance in national forests is primarily the responsibility of the USDA 

FS, but county road maintenance crews maintain some roads. The Federal Highway 

Administration is also involved with the management, design, and funding of roads 

within the USDA FS and NPS.

Each national forest develops a road maintenance plan for every fiscal year, 

primarily based on priorities by operational maintenance level, then by category 

and priority (USDA FS 2011c). Maintenance of forest roads subject to Highway 

Safety Act standards receive priority for appropriated capital maintenance, road 

maintenance, or improvement funds over roads maintained for high clearance 

vehicles. Activities that are critical to health and safety receive priority in decisions 

about which roads to repair and maintain, but are balanced with demands for access 

and protection of aquatic habitat (USDA FS 2011c). 

Both national forests lack the capacity to maintain the entire road system 

because of substantial decrease in timber revenue in recent decades, which previously funded road maintenance (USDA FS 2011b). Maintenance cost varies from 

$420 to $950 per km.5 Given current and projected funding levels, the forests are 

balancing benefits of access with costs of maintaining and operating a sustainable 

transportation system that is safe, affordable, and responsive to public needs, and 

which causes minimal environmental impact. Management actions being implemented to meet these sometimes competing objectives include reducing road maintenance levels, storm-proofing roads, upgrading drainage structures and stream 

crossings, reconstructing and upgrading roads, decommissioning roads, converting 

roads to alternative modes of transportation, and developing more comprehensive 

access and travel management plans (USDA FS 2011b).

Planning and Projects

Foundation statements and general management plans (GMP) of the national parks 

identify laws relevant to travel, such as road building limits and special road or trail 

designations (USDI NPS 1995, 2001, 2011, 2012b). Transportation is not a specific 

mandate or goal of the parks, but travel management helps the parks to meet objectives such as resource protection, recreation, education, and research. Park-specific 

GMPs provide direction for long-term transportation planning. For example, one

5

 Nashida, F. 2011. Personal communication. Assistant forest engineer, U.S. Department of 

Agriculture, Forest Service, Mount Baker-Snoqualmie National Forest, 2930 Wetmore Ave, 

Suite 3A, Everett, WA 98201. 

National forests lack 

the capacity to maintain 

the road system 

because of decreased 

timber revenue.
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goal of the GMP for MORA is to improve management of high-season visitation 

to avoid adverse impacts on park resources and visitor experiences (USDI NPS 

2001). Park-specific GMPs often recommend specific transportation objectives, 

improvements to access and transportation facilities, and partnerships with regional 

transportation planning efforts. These plans can also include decision triggers, such 

as converting roads to trails if substantial flooding occurs and rebuilding is no 

longer feasible. In addition to GMP, large transportation projects have detailed planning assessments, such as the Nisqually to Paradise road rehabilitation (USDI NPS 

2012d), Stehekin River corridor study (USDI NPS 2012a), and Ross Powerhouse 

slide repairs (USDI NPS 2012c).

The NPS is currently developing a 20-year National Long-Range Transportation Plan that is expected to be completed in 2014 and will be updated at least every 

5 years. This plan will address sustainable development and operations with working teams on visitor experience, natural resource stewardship, cultural resource 

stewardship, climate change, livability, law enforcement and safety, asset management, and funding and financial sustainability. Long-range transportation planning 

is legally mandated for all federal land management agencies, and climate change is 

a required component of this planning process (SAFETEA-LU 2005)

Planning for transportation and access on national forests is included in 

forest-specific land and resource management plans. The NWFP (USDA and 

USDI 1994a, 1994b), which amended the forest plans (USDA FS 2012a) of the 

MBSNF and OWNF, included standards and guidelines that apply to road design 

and maintenance, with the objective of mitigating impacts to aquatic habitat and 

federally listed species. For example, new stream crossing structures are required to 

accommodate at least Q100, including associated bed load and debris (USDA and 

USDI 1994b). The NWFP requires development and implementation of a transportation management plan for each forest, including provisions to mitigate impacts to 

aquatic habitat.

The 2001 Road Management Rule (36 CFR 212, 261, and 295) requires national 

forests to use science-based analysis to identify a minimum road system that is 

ecologically and fiscally sustainable. Both the MBSNF and OWNF are currently 

identifying a sustainable road network in accordance with the rule. The goals of 

the minimum roads analysis are to assess the necessity of existing roads, remove 

damaged or unnecessary roads, and maintain and improve necessary roads without 

compromising environmental quality. The minimum roads analysis will have four 

benefits: (1) increased ability to acquire funding for road improvement and decommissioning, (2) a framework to set annual maintenance costs, (3) improved ability to 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

meet agreement terms with regulatory agencies, and (4) increased financial sustainability and flexibility. The minimum roads analysis does not include trails or other 

transportation facilities. Consideration of climate change is not currently a formal 

part of the analysis. 

Similar to national parks, major road projects on the national forests must have 

assessments in compliance with the National Environmental Policy Act (NEPA) of 

1969. Examples of projects on the MBSNF with specific plans include the Suiattle 

Access and Travel Management Plan (USDA FS 2010b) and Granite Creek Road 

Decommissioning and Road to Trail Project (USDA FS 2012b) environmental 

assessments. Decommissioning roads is a process of restoring roads to a more natural state by reestablishing drainage patterns, stabilizing slopes, restoring vegetation, 

blocking road entrances, installing water bars, removing culverts, removing unstable fills, pulling back road shoulders, scattering slash on roadbeds, and completely 

eliminating roadbeds (36 CFR 212.5; Road System Management; 23 U.S.C. 101). 

Major projects, such as revisions of roads and trails or decommissioning, require 

public involvement and an environmental assessment under NEPA. 

Adapting Access Management in a Changing Climate 

During the NCAP workshop on climate change, hydrology, and access, scientists 

and resource managers worked collaboratively to identify key vulnerabilities of 

access management to climatic variability and change and adaptation strategies to 

reduce adverse effects. The workshop included an overview of adaptation principles 

and regional examples of agency efforts to adapt transportation planning and 

management to climate change. Scientists and resource managers identified options 

for adapting access management, as well as potential barriers, opportunities, and 

research needs for implementing adaptation. 

Workshop participants focused on four key sensitivities of roads, trails, and 

infrastructure that will challenge management efforts to provide safe access and 

use for recreation and operations: (1) increased damage associated with higher peak 

flows and more frequent floods; (2) increased damage associated with landslides, 

erosion, and saturated soils; (3) decreased water availability with lower summer 

flows; and (4) changes in visitor use patterns that could lead to higher demand on 

facilities and public safety concerns. In many cases, climate change exacerbates the 

current sensitivities of access management in the North Cascades. The spatial variability of projected changes in flood risk, peak flows, soil moisture, and landslides 

as described above can be used to identify locations with the greatest exposure to 

these changes. 
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Adaptation Options for Higher Peak Flows and 

Flood Risk

Road and Culvert Design and Maintenance

Current road design and management are consistent with adapting to climate 

change in some ways, but changes will likely be necessary (table 4.3). A “no 

regrets” strategy for climate change adaptation is to continue to upgrade the aging 

system of roads and stream crossings as required by the NWFP and the 2001 Road 

Management Rule. These upgrades will increase resilience of roads and stream 

crossings to higher peak flows and flood frequency (Littell et al. 2012). Engineers 

at the MBSNF and OWNF are replacing failing culverts and bridges and disconnecting roads from waterways to mitigate impacts on aquatic ecosystems. Current 

efforts to inventory roads, culverts, and stream crossings for the minimum roads 

analysis will provide critical information for identifying future repairs, replacements, and upgrades. Having this information a priori will enable managers to 

better respond to more frequent floods and higher peak flows. 

Climate change provides a new context for evaluating current practices to 

upgrade roads and culverts. Engineers may consider prioritizing upgrades of culverts and roads in mixed-rain-and-snow basins (Littell et al. 2012) or using a new 

method for calculating Q100 for sizing culverts that considers future peak flows 

(Halofsky et al. 2011). Culverts on non-fish-bearing streams are sized for Q100 plus 

a factor related to expected debris load during floods, but currently Q100 is calculated with equations based on historical flood statistics that do not consider projected changes in peak flows. Engineers may consider using model projections of 

future Q100 (e.g., from the VIC hydrologic model) or maps of the spatial variability 

in future flood risk (fig. 4.4) to identify priority areas for increasing culvert capacity above historical values (Halofsky et al. 2011). Crossings for fish-bearing streams 

on national forest lands use stream simulation design standards and requirements of 

consultation documents for the U.S. Endangered Species Act, resulting in openings 

that far exceed capacity for a Q100 flow. These culverts greatly increase capacity 

and will be more robust to higher peak flows in a changing climate. Where these 

larger structures are needed to restore aquatic habitat, this design choice is a “no 

regrets” strategy for improving culvert longevity in a changing climate because the 

performance is relatively insensitive to increasing high flows.

The MBSNF and OWNF have a large backlog of culverts and road segments 

in need of repair, replacement, or upgrade even under current hydrologic regimes. 

Limited funding and staff hinder current efforts to upgrade the system to current 

standards and policies, so the additional cost of upgrades to accommodate future 

hydrological regimes is a barrier to adaptation. However, extreme floods that 

Climate change 

provides a new context 

for evaluating current 

practices to upgrade 

roads and culverts. 
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Table 4.3—Climate change sensitivities of road design and maintenance to increasing flood risk; adaptation strategies and tactics to reducethese sensitivitiesAdaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs

Sensitivity: Higher peak flows leading to increased road damage at stream crossings.

Strategy: Increase resilience of stream crossings, culverts, and bridges to higher peak flows.

• Continue to replace culverts with higher capacity 

culverts

• Complete unit-wide inventory of culverts and 

bridges, including GPS locations of structures and accurate culvert data

• Consider a process for replacing culverts based on 

projected future, rather than historical, peak flows

• Consider prioritizing structure replacement in 

high-risk (mixed-rain-and-snow) watersheds

• Reroute roads out of flood plains

Opportunistic, short term

Structure failures are an opportunity to upgrade stream crossings.Collect GPS locations of structures as projects are completed

Limited fundingCurrent backlog of deferred maintenance and upgrades to meet current standardsLarge number of culverts and roads in need of replacement, repair, or rerouteIncomplete culvert survey informationERFO limitations on replacement of only current structures

Centralized and standardized database of projects and upgradesEmergency Relief for Federally Owned Roads (ERFO) justifications for bettermentsMethod for ranking culverts for replacement

Alternative methods for modeling changes in future peak flows

Strategy: Increase resistance of road surfaces to higher peak flows at stream crossings.

• Install hardened stream crossings• Perform a basinwide assessment of current 

hydrological interactions with roads

• Continue to use grade control structures, humps, 

and water bars to reduce velocity and redirect flow

Short term Ongoing maintenance, repair, and replacement projects after flood events ERFO justifications for betterments

Monitoring to assess performance and effects on hydrologic response and aquatic habitat

Effects of hardened crossings on drainage paths and aquatic resources

Strategy: Facilitate the response to higher peak flows by reducing the road system and thus flooding of roads and stream crossings.

• Continue to decommission roads with high risk 

and low access

• Convert use to other modes of transportation (e.g., 

from vehicle to bicycle or foot)

• Change user expectations with public education

Opportunistic, long term

Partnerships and collaboration with other agencies that are also disconnecting roads from waterwaysCurrent planning processes: long-range transportation planning, travel management plans, general management plans, and land and resource plans

High cost of decommissioning roads

Public and political opposition to road closures and loss of access
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damage roads and culverts can be opportunities to replace existing structures with 

ones that are more resilient to higher peak flows. These replacements, called “betterments,” can be difficult to fund under current Emergency Relief for Federally 

Owned Roads (ERFO) program eligibility requirements when used to fix damage 

from extreme events because the current policy is to only replace in kind. In some 

cases, matching funds can be raised or betterments can be funded with sufficient 

justification and documentation of the environmental impacts. Justification for betterments based on the latest climate change science would facilitate this approach. 

Increasing resilience to higher peak flows will not be possible for all road 

segments because of limited funding for maintenance and because resilience will 

become less feasible over time as peak flows continue to increase. Adapting road 

management to climate change in the long term may require further reductions in 

the road system for road segments where increasing resilience is not feasible and 

demand for access is not high. Engineers at the MBSNF and OWNF are reducing 

the road system by closing, decommissioning, or converting roads to nonvehicular 

modes of transportation. Road segments that are candidates for decommissioning 

are typically those with low demand for access, high risks to aquatic habitat, a 

history of frequent failures, or combinations of the three. Okanogan-Wenatchee 

National Forest road managers also consider use of roads for fire management (fire 

suppression, prescribed fire, and hazardous fuel treatments); further reductions in 

the road system on OWNF may conflict with efforts to manage forest vegetation for 

increased resilience to climate change (see chapter 5). 

Climate change provides a new context for prioritizing roads for decommissioning and closure. Engineers may consider emphasizing roads for decommissioning that are in basins with higher risk of increased flooding and peak flows (figs. 

4.3 and 4.4), in flood plains of large rivers, or on adjacent low terraces. Information 

on locations in the transportation system that currently experience frequent flood 

damage (box 4.6) can be combined with spatially explicit data on projected changes 

in flood risk and current infrastructure condition to provide indicators of where 

damage is most likely to continue and escalate with changes in climate. Optimization approaches (e.g., linear programming) can be used to balance these multiple, 

competing objectives and constraints while minimizing the overall costs of the road 

system.6

Most roads in MORA and NOCA have high demand for access because of the 

small road network and lack of redundancy, but increasing flood risk may require

6 Strauch, R.; Hamlet, A.F. [N.d.]. Use of linear programming and climate change threats 

to access in a minimum forest roads analysis in the North Cascades region. On file with: 

Strauch, R., University of Washington, Civil and Environmental Engineering, Seattle, WA 

98195 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Box 4.6—Next steps: assessing access vulnerability in the 

North Cascades

An integrated understanding of climate change exposure and current and expected 

sensitivities can be used to develop a more quantitative and spatially explicit vulnerability analysis of the degree to which the transportation system may be affected. 

One method is to begin by examining the effects observed with past climatic variability, such as locations of “repeat offenders,” segments of the transportation system 

that have been repeatedly damaged by floods or landslides (see figure). Local land 

managers have the unique expertise to identify locations of repeat offenders. This 

information can be combined with the spatial variability of projected changes in climate, snowpack, and hydrologic regimes to develop a quantitative, spatially explicit 

vulnerability assessment, which can be integrated into other management objectives 

and used to inform adaptation strategies.
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general technical report pnw-gtr-892 Table 4.4—Climate change sensitivities of facilities, structures, and cultural resources to increasing flood risk; adaptation strategies and tactics to reduce these sensitivities Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs Sensitivity: Higher peak flows leading to increased damage and disrupted access to facilities and cultural and historical resources.

Strategy: Increase resistance of infrastructure and cultural and historical resources.

• Stabilize banks near resources with rip-rap or 

vegetation 

Opportunistic, short term

Repair and replacement of projects after flood events

Limited funding New designs for slope 

stabilization

• Consider increased use of engineered logjams 

to redirect flows

Current planning processes: long-range transportation planning, Travel Management Rule, general management plans, land and resource management plans

Emergency Relief for Federally Owned Roads regulations for replacing “in-kind” vs. betterments

Monitoring to assess performance and effectsMaps of flood plain channel migration areas

Strategy: Increase resilience of the floodplain. Public and political opposition to 

road closures and loss of access

• Restore natural function of the floodplain 

allowing waterways to migrate

Opportunistic, long-term

• Remove or modify infrastructure allowing 

channels to migrate within the floodplain
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road closures or changes in use. For example, the Carbon River Road in MORA 

(fig. 4.11), which is below the current elevation of the river, has been repeatedly 

damaged by floods and was severely damaged in the flood of November 2006. 

The road provides sole access to a campground, historic landmark district, and 

trailhead, yet the high cost to repeatedly repair the road and mitigate impacts to 

aquatic habitat make it too costly to maintain existing access. Managers worked 

with recreation groups to develop a plan to convert the road from vehicle use to 

bike and foot travel. This is an example of a “win-win” adaptation tactic; converting the mode of travel on roads from vehicles to bicycles or foot traffic. Adapting 

access management to climate change may require more compromises such as this 

between maintaining access versus high maintenance costs and risks to aquatic 

habitat and human safety. 

Reducing the road system in the national forests and national parks will present 

both barriers and opportunities (table 4.3). Decommissioning roads or converting 

roads to trails is expensive and must be done properly to reduce adverse effects on 

water quality and aquatic habitat. In the case of the Carbon River Road, the road 

is designated as a National Historic Landmark District, which created an obstacle 

to changing its use. Furthermore, reductions to the road system are often met with 

opposition from the public accustomed to using roads for recreational access, but 

public involvement in road decisions can also be an opportunity to increase awareness and develop more “win-win” adaptation options. Thus, one adaptation tactic is 

to adjust visitation patterns and visitor expectations by actively involving the public 

in road decisions related to climate change. This has the added benefit of raising 

political support and funding from external sources to help maintain access. On the 

other hand, the limited roads for vehicle access in the parks, especially at MORA, 

may require managers to consider adding new roads and facilities in alternative 

locations when current access is lost because of infrastructure damage or to accommodate increased use as population and demand increases. Adding roads or relocating existing roads may require adjustments to wilderness boundaries. Partnerships 

with recreation groups will be increasingly important for raising public awareness 

of climate change threats to access and for identifying successful adaptation 

options.

Facilities, Structures, and Cultural Resources 

As with roads, the increased risk of flooding with climate change in some basins 

may require modification to current management of facilities and historical and 

cultural resources (table 4.4). In addition to higher flood risk, floodplains may 

expand because of channel aggradation, as has occurred in MORA where several 

Decommissioning 

roads is expensive and 

must be done properly 

to reduce adverse 

effects on water quality 

and aquatic habitat.
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general technical report pnw-gtr-892 Table 4.5—Climate change sensitivities of trails to increasing flood risk; adaptation strategies and tactics to reduce these sensitivities Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs Sensitivity: Higher peak flows and flood frequency may increase damage to trails and bridges, requiring more maintenance, replacements, or closures. Strategy: Increase resilience of trail system to higher peak flows by repairing, replacing, and re- routing trails and trail bridges with high demand for access. • Continue to upgrade trail bridges with stronger rot-resistant materials • Continue relocating bridges to locations with stronger parent material if possible • Reroute trails above waterways with highest 

flood risk

• Increase long-range planning to prioritize 

trail and bridge repair, replacement, and reroute 

• Request additional funding to prepare for 

more trail and bridge failures 

• Focus on acquiring funding for high-profile 

projects (based on co-benefits of public demand and safety) 

• Consider increasing the height of bridges 

above waterways 

• Collaborate with hydrologists to consider 

future peak flows in design of new trials and trial bridges 

Opportunistic short term, long term 

Grants for repairing damage to highvalue trailsDamage to high-value trails increases opportunities for volunteerism and partnerships with user groupsTrail failures are an opportunity for replacement and upgrade.Partnerships with user groups can leverage fundingMultiagency coordination through North Cascadia Adaptation Partnership (NCAP)

Additional cost of rerouting rather than rebuilding trails, stronger materials for bridges and trails, and increasing the height of bridgesNational Environmental Policy Act compliance required for rerouting trails

Method for determining high-risk trails and trail bridgesMethod for modeling changes in future peak flows for use in bridge location and designPotential for additional climate change impacts to trail maintenance such as windthrow

Strategy: Leverage partnerships with recreational user groups to increase awareness of threats to access and adjust user expectations. 

• Improve outreach publically and internally• Increase efforts to collaborate with 

volunteers and build capacity for trail maintenance

• Collaborate with user groups to educate the 

public and increase political support and funding to maintain access

• Coordinate between agencies for a consistent 

message on access and climate change

Opportunistic, short term

Current frequent collaboration and partnerships with recreation user groupsMultiagency coordination through NCAP
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs

Strategy: Reduce the system of trails and trail bridges. 

• Abandon damaged trails with low use and 

high flood risk

• Continue to reroute trails in locations that 

eliminate the need for trail bridges

Opportunistic, long term

Trail and bridge failures are an opportunity to abandon or reroute trails Institutional reluctance to close trails, even trails with frequent 

failuresLimited capacity for adaptive managementLimited capacity to incorporate new science and monitoring results into long-term planningInability of long-range planning to respond to short-term needs

Social science research to understand public response to changes in access

Table 4.5—Climate change sensitivities of trails to increasing flood risk; adaptation strategies and tactics to reduce these sensitivities (continued)
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facilities in Longmire, including the emergency operations center and helibase, are 

threatened by expansion of the Nisqually River floodplain. In most cases, the high 

cost of relocating buildings and inability to move historic sites from the floodplain 

will require that adaptation options focus on resistance, preventing flood damage 

despite increasing risk. Stabilizing banks reduces risk to infrastructure, and using 

bioengineering rather than rip-rap or other inflexible materials may be a longer 

term solution that has a lower environmental impact, is more politically acceptable, 

and is less likely to shift flooding impacts downstream. For example, the NPS 

is considering increasing the use of engineered logjams in waterways to redirect 

water away from critical infrastructure. Another tactic for adapting to flood risk is 

a storm patrol or watch system that identifies threats early, such that rapid response 

can minimize impacts to life, infrastructure, and moveable property. These 

approaches would not protect fixed structures, such as buildings, from flooding.

In the long term, protecting infrastructure in place will be more difficult as 

flood risk continues to increase. Long-term adaptation strategies may require 

removing (or not rebuilding) infrastructure in the floodplain to allow river channels to migrate and accommodate the changing hydrologic regime within the flood 

plain. The land and resource management plans of the USDA FS and the general 

management plans of the NPS are opportunities to implement these long-term adaptation tactics for the management of facilities and infrastructure because of their 

long-term planning horizons. 

Trail Maintenance and Design

Managing trails in the context of climate change will require increased resilience 

to higher peak flows and flood frequency (table 4.5). Managers at MBSNF and 

MORA are currently repairing and replacing trail segments and bridges damaged 

during the extreme floods of 2003 and 2006. In many cases, current repairs and 

reroutes of trails and upgrades or elimination of trail bridges are robust actions that 

will also increase resilience to future hydrologic regimes. For example, trail managers at the MBSNF frequently reroute trails further from streams and rivers and to 

locations that do not require bridges. Bridges that are replaced are often constructed 

from more durable and rot-resistant materials, elevated higher above the riverbed, 

made wider to accommodate expanding flood plains, and located on sites with 

stronger parent material to prevent future failures. Adapting to climate change may 

require changes to these practices, such as building trail bridges higher or longer, 

to accommodate projected future rather than historical peak flows. As with road 

design, improved design for higher peak flows may require an alternative method 

Protecting 

infrastructure in place 

will be more difficult as 

flood risk continues to 

increase.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

for calculating Q100 plus debris, which is also used to determine trail bridge design.

The national forests lack funds necessary to fully meet trail management objectives under current hydrologic regimes, so funding additional repairs, replacements, 

and upgrades to increase resilience to climate change will be challenging. However, as with road maintenance and design, extreme floods that cause widespread 

damage can provide opportunities to fund upgrades that will increase resilience 

to current flooding regimes and climate change. Damage to high-profile trails, 

such as the Pacific Crest Trail that runs north-south through the North Cascades, 

has motivated public action and political pressure to repair the trail and maintain 

access. Funding from ERFO, which was historically allocated to repair only roads, 

was allocated to repair trail segments in the case of this high-profile trail. Upgrades 

to the trail system to increase resilience will require additional funding, but also 

creative solutions to funding challenges. Future damage to high-profile trails may 

provide opportunities to request additional funds, and increase public awareness 

of the rising cost of maintaining trail access in a changing climate. Many high-use 

trails in the North Cascades cross national forest and national park boundaries, so 

the NCAP provides an opportunity to increase coordination and combine resources 

to reduce impacts to access. Managers may consider increasing efforts to build 

partnerships with recreational user groups in response to increasing damage to the 

trail system (table 4.5).

Increasing resilience of the trail system will probably continue to be an appropriate adaptation strategy for high-demand trails, but in some areas, feasibility of 

this strategy will decrease with time as hydrologic regimes continue to change. As 

with roads, managers may need to consider closing or stopping maintenance of lowuse, low-resilience trails. Trails and trail bridges repeatedly damaged by floods will 

become likely candidates for closure. Trail closures that reduce access will often 

face public and agency opposition, but the long-term planning frameworks of the 

USDA FS and NPS create opportunities to revise objectives and incorporate these 

longer term changes in recreation management. On the other hand, these long-term 

plans can limit the ability to respond to short-term needs triggered by extreme 

events, so incorporating decision triggers in the long-term planning process may 

provide managers with the ability to respond to climate-related events with actions 

already vetted by public review and input. Adaptive management such as this can 

be used to assess and monitor the trail system as damage frequency increases and 

allow decisions regarding restoration and closures to evolve as hydrologic regimes 

evolve. 
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Adaptation Options for Higher Soil Saturation and 

Landslide Risk

Road and Facility Maintenance and Design

As with increasing flood risk, adapting road and facility management to increased 

soil saturation in winter landslides risk and may require increasing resilience of the 

road system (table 4.6). Short-term adaptation tactics may include improving drainage, stabilizing slopes, restoring vegetation cover, reducing weight on the road, 

altering road surface type, or accepting higher maintenance costs. In the long term, 

however, repeated landslides and slope failures may require that highly vulnerable 

roads and infrastructure be closed and new construction limited in locations with 

elevated landslide risk. Although we hypothesize that the combination of increasing 

winter precipitation and soil moisture will increase winter landslide risks (as discussed above), more comprehensive and detailed scientific information is needed on 

how changes in precipitation, snowpack, vegetation, and ground water will interact 

to affect the risks of landslides and slope failure.

Trail Maintenance and Design

More precipitation falling as rain rather than snow at mid elevations and more 

rapid spring snowmelt may increase soil saturation and create boggy areas around 

trails, causing more damage to trails and surrounding sensitive vegetation (e.g., 

meadows). Recreation managers may consider increasing maintenance in locations 

with projected increases in winter soil moisture (figs. 4.9, 4.12). Some trails may 

require reroutes to avoid damage to vegetation when users stray off established 

trails to avoid saturated soils or inundated sections. Climate change increases the 

importance of considering hydrologic impacts in trail design, such as designs that 

effectively drain storm runoff without sustaining damage (table 4.7). Monitoring 

saturated soils around trails will be important for identifying damage and prioritizing locations for restoration and repair. Monitoring may be more effective and 

efficient if it focuses on trails in areas with the greatest projected increases in soil 

moisture (fig. 4.9) and mixed-rain-and-snow basins (fig. 4.3), which are expected to 

experience the biggest shifts from snow to rain and substantial declines in snowpack that cause elevated soil moisture in late autumn and early winter. 

More saturated soils are expected to increase landslides, erosion, and associated damage to trails. Recreation managers may consider increasing trail resilience 

by designing and constructing trails with better erosion control using vegetation 

or physical structures (table 4.7). Training of seasonal trail maintenance crews 

and volunteers provides opportunities to emphasize the importance of drainage 

improvement techniques. Trails that experience repeated failures from erosion and 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 4.6—Climate change sensitivities of roads and structures to increasing erosion and landslides; adaptation strategies and tactics to reduce these sensitivitiesAdaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs

Sensitivity: Increased landslides leading to more road closures, higher maintenance costs, and disrupted access.

Strategy: Increase resilience to landslides by protecting roads and structures from higher landslide frequency.

• Increase maintenance frequency• Stabilize slopes mechanically or with 

vegetation

• Improve drainage• Alter road surface type and grade• Elevate roads to allow landslides to pass 

underneath

• Compensate for landslides by reducing 

weight

Short term Streamlined National Environmental 

Policy Act (NEPA) process when landslides are emergency eventsPartnerships (volunteer hours, share local expertise in landform mapping, compare case studies) Leverage existing requirements for changes in facility maintenance

NEPA cost-benefit analysisERFO regulationsLimited staff capacityLimited fundingEndangered Species Act regulations and limitations

Site-specific stability analysis based on soil and geologic informationIdentification of areas sensitive to higher landslide frequency

Strategy: Allow for increased landslide frequency by relocating roads and structures.

• Close and decommission roads in areas of 

high landslide risk.

• Locate new construction or reroute roads 

away from areas of high landslide risk.

• Collaborate with partners to compare 

data of current damage with data on soil moisture and landforms to identify sensitive areas.

Opportunistic, long term

Current planning processes: longrange transportation planning, Travel Management Rule, general management plans, land and resource management plans

Competing needs of aquatic habitat and accessPublic and political opposition to road closuresDisrupted access to private property or other ownerships

Identification of areas sensitive to higher landslide frequencyClimate change and landslide risk assessmentData on patterns of human useExpense of converting roads to trails or decommissioning
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general technical report pnw-gtr-892 Table 4.7—Climate change sensitivities of trails to increasing erosion, landslides, and saturated soils; adaptation strategies and tactics to reduce these sensitivities Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs Sensitivity: Increased trail failures associated with erosion and landslides. 

Strategy: Increase resilience of trail system to 

erosion. 

• Increase restoration and erosion control 

with revegetation projects 

• Reduce erosion by building protection into 

trail design

• Increase monitoring of ground water to 

assess risk of landslides and slope failures

Opportunistic, short term,

Landslides provide an opportunity to identify where action is neededDramatic landslide events can catalize action.

Lead time required for plant supply of appropriate native plantsLimited capacity for funding, personnel, and supplies

Site-specific stability analysis based on soil and geologic information

Sensitivity: Increased soil saturation, which will increase the need for trail maintenance.

Strategy: Increase resilience of trail systems to 

saturated soils.

• Inventory frequently saturated areas and 

prioritize changes in trail locations

• Locate piezometer where the greatest 

impacts are expected (e.g., mixed rain and snow basins)

• Reroute high-risk trails that experienced 

post problems with saturated soils

Cost-effectiveness and costbenefit analysis of piezometersIdentification of areas sensitive to higher soil moisture
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

landslides are good candidates for rerouting or closure, but high-demand, high-use 

trails that cannot be closed will require planning to accommodate higher maintenance costs and more frequent or longer closures for repairs.

Adaptation Options for Visitor Use Patterns 

and Public Safety

More frequent failures in the road and trail system may increase risks to public 

safety. Limited resources and staff make it difficult for national forests and national 

parks in the NCAP to quickly repair damage, yet the public expects continuous 

access. In response to climate change, managers may consider implementing and 

enforcing more restrictions on access to areas where trails and roads are damaged 

and safe access is uncertain (table 4.8). Greater control of seasonal use, combined 

with better information about current conditions, especially during the shoulder 

season (i.e., early spring and late autumn) before and after active maintenance, may 

help ensure better public safety. Partnerships with recreation groups may generate 

opportunities to convey this message to a larger audience, thus enhancing public 

awareness of hazards and the safety of recreation users.

Managers may consider adapting recreation management to changes in visitor 

use patterns in early spring and late autumn in response to reduced snowpack and 

warmer temperatures (table 4.8). An expanded visitor season would increase the 

cost of operating facilities (e.g., visitor centers and campgrounds), but revenue from 

user fees may also increase. Limitations on staff because of funding or other constraints may also present obstacles to an expanded visitor season. One adaptation 

tactic to increase agency capacity to respond to higher visitation and a longer visitor 

season may be to reduce restrictions on the length of seasonal employment, and 

fund staff with user fees that respond directly to increased use, rather than fixed 

budgets. Another adaptation tactic to reduce the impact of higher visitor use is to 

provide alternative modes of transportation, which is already being implemented in 

MORA and NOCA. Mount Rainier National Park uses a shuttle service during peak 

visitation to decrease the demand on visitor facilities and impacts to ecosystems. In 

the Upper Stehekin Valley, NOCA changed access from shuttle to stock or horse in 

response to repeated flood damage. General management plans and the long-term 

transportation planning framework provide opportunities to address anticipated 

changes in the amount and timing of visitation. Adaptive management can be used 

to monitor changes in the timing, location, and number of visitors, thus providing 

data on where management can be modified in response to altered visitor patterns. 

As discussed above, alternate methods of funding seasonal employees may need to 

be considered.

More frequent failures 

in the road and trail 

system may increase 

risks to public safety.
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general technical report pnw-gtr-892 Table 4.8—Climate change sensitivities of visitor use and public safety; adaptation strategies and tactics to reduce these sensitivities Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs Sensitivity: Increased risk to public safety associated with trail and trail bridge failures. Strategy: Minimize risks to public safety. • Evaluate and monitor timing of visitor use relative to hydrologic dynamics Opportunistic, short term Volunteer training Public and political opposition to limitations and loss of access Monitor visitor response to limitations and warnings • Limit visitor access when safety is a concern Shuttle services within parks • Coordinate with recreational user groups to educate the public about safety concerns associated with increased bridge and trail damage Sensitivity: Fewer campgrounds, greater use of alternative campgrounds, reduced services, and greater use of fewer facilities.

Strategy: Prevent flood damage to high use campgrounds.

• Protect campgrounds from initial increase 

in flood risk 

• Accept higher maintenance costs associated with more floods

Facilities with cultural significance have greater priority for protection

Extent to which current facilities can handle increased visitation (i.e., current capacity)

Short term

Strategy: Increase resilience of facility and campground system to maintain access. 

• Abandon campsites in higher risk 

locations but add sites in other locations, conserving the total number of sites

Long term Availability of alternative sites to 

replace closed campgrounds and facilities 

• Educate the public about how funds are 

allocated to relocate sites but the total number of sites is conserved 

• Redirect, but not require, changes in 

visitor use of facilities

Strategy: Accept loss of campgrounds and other recreation facilities.

• Close and abandon sites• Change timing or route of access• Change the nature of the access 

mechanism

Long term Public attachment to the site can motivate collaboration and solutions Public and internal resistance to change because of attachment to 

certain sites and activities at those sitesConflicts between user groupsUsers desire to be near water

Social science research to understand public response to these changes
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Adaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needs

Sensitivity: Increased demand for access with increasing length of the snow-free season.

Strategy: Maintain safe access at the beginning and end of the summer recreation season.

• Educate the public about risks associated 

with early- and late-season access

• Open trails, campgrounds, and facilities 

earlier in the season

• Limit access when public safety is a 

concern

• Implement adaptive management—alter 

management as the length of the recreation season changes

Long term Long-range planning (general management plans, land and resource management and annual operation plans) Limitations on seasonal hiring Cost of having facilities open longer Locations of future increases in recre- ational use

Table 4.8—Climate change sensitivities of visitor use and public safety; adaptation strategies and tactics to reduce these sensitivities (continued)
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Adaptation Options for Dry-Season Water Availability 

and Use 

Lower soil moisture and low flows (7Q10) in late summer combined with increasing demand for water will likely reduce water availability for aquatic resources, 

recreation, and operations. Stream crossing structures can be adapted to lower 

7Q10 flows by incorporating structures that better maintain low flow channels 

and stream connectivity. National forests and national parks in the NCAP rely on 

water for facility operations, visitors, and residences. Adapting to a lower water 

supply may require tactics that evolve over time (table 4.9). A sufficient water 

supply for critical operations and facilities can be augmented by constructing new 

wells; increasing capacity to store water with cisterns, water towers, and reservoirs; 

developing gray water recycling systems; or importing water from outside the 

region. However, these are relatively high-cost solutions that may be feasible only 

in the most high-use areas where maintaining current dry-season water supply is 

a priority, or in areas where critical uses like fire protection must be supported to 

protect buildings and other infrastructure.

In the long term, increasing water conservation and reducing user expectations 

of water availability are relatively inexpensive and complementary adaptation 

tactics for maintaining adequate water supply. Water conservation can be increased 

with upgrades to facilities (administrative buildings, housing, visitor centers, and 

campgrounds) that reduce water use, and through development of gray water recycling systems. In areas with the greatest reductions in low summer flows (fig. 4.5), 

it may no longer be possible to provide water at current levels, requiring that water 

availability in campgrounds be reduced or that facilities be closed during the dry 

season or years with low water availability. These tactics will require a shift in user 

expectations that can be facilitated by increasing public outreach and education.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 4.9—Climate change sensitivities of dry-season water availability; adaptation strategies and tactics to reduce these sensitivitiesAdaptation tactics Timeframes Opportunities for implementation Barriers to implementation Information needsSensitivity: Decreased water and potable water availability with reduced snowpack, lower summer precipitation, and increased demand in the dry season.

Strategy: Maintain sufficient water supply to meet demand. 

• Attribute causes of potable water loss to 

determine appropriate response 

• Investigate alternative water sources (e.g., 

ground water)

• Consider constructing new wells, cisterns, and 

reservoirs

• Increase water storage with artificial storage 

infrastructure (e.g., water towers)

• Import water from other regions

Short term, long term

Partner with universities or organizations (e.g. architects-without-borders, engineers-without-borders) to develop new designs or retro-fits

High cost of water storageWells may not be productiveUncertainties in water supply system

Identification of potential locations of limited dry-season water availabilityAttribute low water availability to reduced snowpack or other causesFuture increases in water demand

Strategy: Increase resilience through water conservation.

• Install waterless urinals and low-flow, solar, 

and composting toilets 

• Institute gray water recycling• Educate the public about water shortages and 

conservation

• Reduce water provided in campgrounds and 

other facilities

• Change user expectations of water availability• Reduce campground capacity to decrease 

water demand

• Close facilities when water is not available

Short term, long term

Public interest and education can motivate actionDrought can motivate actionLong-range planning (general management plans and land and resource management plans)

Limited funding to increase water efficiency in facilitiesRestrictions on modification to cultural and historic resources
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Acknowledgments 

We thank members of the natural resource, facilities, and administrative staffs at 

Mount Baker-Snoqualmie National Forest, Okanogan-Wenatchee National Forest, 

North Cascades National Park Complex, and Mount Rainier National Park for 

their expertise and input during workshops and subsequent discussions, including Jon Reidel, Jack Oelfke, Chip Jenkins, Roger Andrascik, Barbara Samora, 

Jim Ziolkowski, Eric Walkinshaw, Scott Beason, Amy Lieb, Felix Nishida, Peter 

Wagner, Gary Paull, and Marjorie Hutchinson. We thank colleagues at the University of Washington, Climate Impacts Group for their assistance with climate data 

and analysis. Chip Jenkins, Jon Reidel, Michael Furniss, and Scott Beason provided 

helpful reviews of this chapter. 

Literature Cited

Abbe, T.; Beason, S.R.; Kennard, P.M.; Park, J. 2010. Rivers gone wild: 

mountain river response to a warming climate in the Pacific Northwest. 

Freshwater. 2: 10–13.

Baum, R.; Harp, E.; Highland, L. 2007. Landslide hazards in the Seattle, 

Washington, area. Fact Sheet 2007-3005. Denver, CO: U.S. Department of the 

Interior, Geological Survey. 4 p. http://pubs.usgs.gov/fs/2007/3005/pdf/FS07-

3005_508.pdf. (30 October 2012).

Baum, R.L.; Chleborad, A.F.; Schuster, R.L. 1998. Landslides triggered by the 

winter 1996–97 storms in Puget Lowland, Washington. Open File Rep. 98-239. 

Denver, CO: U.S. Department of the Interior, Geological Survey. http://pubs.usgs.

gov/of/1998/ofr-98-239/ofr-98-239.html. (19 October 2012).

Beason, S.R.; Kennard, P.M. 2007. Environmental and ecological implications 

of aggradation in braided rivers at Mount Rainier National Park. In: Selleck, 

J., ed. Natural resource year in review—2006. Pub D-1859. Denver, CO: U.S. 

Department of the Interior, National Park Service: 52–53. 

Brooks, S.; Crozier, M.J.; Glade, T.; Anderson, M.G. 2004. Towards establishing 

climatic thresholds for slope instability: use of a physically-based combined soil 

hydrology-slope stability model. Pure and Applied Geophysics. 161: 881–905.
103

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Chatwin, S.C.; Howes, D.E.; Schwab, J.W.; Swantson, D.N. 1994. A guide 

for management of landslide-prone terrain in the Pacific Northwest. Land 

Management Handbook No. 18. 2nd ed. Victoria, BC: Ministry of Forests, 

Research Program. 10 p.

Croke, J.; Hairsine, P. 2006. Sediment delivery in managed forest: a review. 

Environmental Reviews. 14: 59–87

Crozier, M.J. 1986. Landslides: causes, consequences, and environment. Dover, 

NH: Croom Helm, Ltd. 252 p.

Crozier, M.J. 2010. Deciphering the effect of climate change on landslide activity: 

a review. Geomophology. 124: 260–267.

Cruden, D. 1991. A simple definition of a landslide. Bulletin of the International 

Association of Engineering Geology. 43: 27–29.

Cui, Y.; Mahoney, E.; Herbowicz, T. 2013. Economic benefits to local communities from national park visitation and payroll, 2011. Natural Resour. Rep. NPS/

NRSS/EQD/NRR—2013/632. Fort Collins, CO: U.S. Department of the Interior, 

National Park Service, Natural Resource Stewardship and Science. 28 p.

Dominguez, F.; Rivera, E.; Lettenmaier, D.P.; Castro, C.L. 2012. Changes in 

winter precipitation extremes for the western United States under a warmer 

climate as simulated by regional climate models. Geophysical Research Letters. 

39: 1–7. doi:10.1029/2011GL050762.

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. doi: 10.1007/s10584-010-9855-0.

Elsner, M.M.; Littell, J.; Binder, L.W., eds. 2009. The Washington climate 

change impacts assessment: executive summary. Seattle, WA: University of 

Washington, Center, for Science in the Earth System, Joint Institute for the 

Study of the Atmosphere and Oceans. 1: 20. 

Glade, T.; Crozier, M.J. 2005. The nature of landslide hazard and impact. In: 

Glade, T.; Anderson, M.; Crozier, M., eds. Landslide hazard and risk. Chichester, 

United Kingdom: Wiley: 43–74.

Granshaw, F.D.; Fountain, A.G. 2006. Glacier change (1958–1998) in the North 

Cascades National Park Complex, Washington, USA. Journal of Glaciology. 52: 

251–256.
104

general technical report pnw-gtr-892

Halofsky, J.E.; Shelmerdine, W.S.; Stoddard, R. [et al.]. 2011. Climate change, 

hydrology, and road management at Olympic National Forest and Olympic 

National Park. In: Halofsky, J.E.; Peterson, D.L.; O’Halloran, K.A.; Hoffman, 

C.H., eds. 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: 21–42. 

Chapter 4.

Hamlet, A.F.; Elsner, M.M.; Mauger, G.S.; Lee, S. Tohver, I.; Norheim, R.A. 

2013. An overview of the Columbia Basin climate change scenarios project: 

approach, methods, and summary of key results. Atmosphere-Ocean. 51(4): 

392–415.

Hamlet, A.F.; Lettenmaier, D.P. 1999. Effects of climate change on hydrology 

and water resources in the Columbia River Basin. Journal of the American 

Water Resources Association. 35: 1597–1623.

Hamlet A.F.; Lettenmaier, D.P. 2007. Effects of 20th century warming and 

climate variability on flood risk in the western US. Water Resources Research. 

43: W06427. 

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 

United States. Journal of Climate. 18: 4545–4561.

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. 20: 1468–1486.

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. In: Hamlet, A.F.; Carrasco, P.; 

Deems, J. [et al.]. Final project report for the Columbia Basin climate change 

scenarios project. Seattle, WA: University of Washington, Climate Impacts 

Group. Chapter 4. http://warm.atmos.washington.edu/2860/r7climate/study_

report/CBCCSP_chap4_gcm_final.pdf. (29 October 2012).

Harp, E.L.; Chleborad, A.F.; Schuster, R.L. [et al.]. 1997. Landslides and 

landslide hazards in Washington state due to February 5–9, 1996, storm. 

Admin. Rep. Reston, VA: U.S. Department of the Interior, Geological Survey. 

29 p. http://faculty.washington.edu/kramer/522/USGS1996StormSlides.pdf.

(30 October 2012).
105

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Huggel, C. 2009. Recent extreme slope failures in glacier environments: effects of 

thermal perturbations. Quaternary Science Reviews. 28: 1119–1130.

Intergovernmental Panel on Climate Change [IPCC]. 2007. Summary for 

policymakers, In: Parry, M.L.; Canziani, O.F.; Palutikof, J.P. [et al.], eds. 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, and New York: Cambridge 

University Press: 7–22.

Istanbulluoglu, E.; Tarboton, D.G.; Pack, R.T.; Luce, C.H. 2004. Modeling of 

the interactions between forest vegetation, disturbances, and sediment yields, 

Journal of Geophysical Research. 109: F01009.

Joyce, L.; Abers, J.; McNulty, S. [et al.]. 2001. Potential consequences of climate 

variability and change for the forests of the United States. In: Melillo, J.; Janetos, 

A.; Karl, T., chairs. Climate change impacts on the United States: the potential 

consequences of climate variability and change. Cambridge, United Kingdom: 

Cambridge University Press: 489–524. Chapter 17. 

Kim, S.K.; Hong, W.P.; Kim, Y.M. 1991. Prediction of rainfall-triggered 

landslides in Korea. In: Bell, D.H., ed. Landslides. Proceedings of the 6th

international symposium on landslides. ChristChurch, New Zealand, University 

of Canterbury. Rotterdam: A.A. Balkema: 2: 989–994. 

Liang, X.; Lettenmaier, D.P.; Wood, E.F.; Burges, S.J. 1994. A simple 

hydrologically based model of land surface water and energy fluxes for GSMs. 

Journal of Geophysical Research. 99: 14415–14428. 

Littell, J.S.; Elsner, M.M.; Mauger, G.S. [et al.]. 2011. Regional climate and 

hydrologic change in the Northern US Rockies and Pacific Northwest: internally 

consistent projections of future climate for resource management. Project report. 

http://cses.washington.edu/picea/USFS/pub/Littell_etal_2010/Littell_etal._2011_

Regional_Climatic_And_Hydrologic_Change_USFS_USFWS_JVA_17Apr11.

pdf. (30 October 2012).

Littell, J.S.; Peterson, D.L.; Millar, C.I.; O’Halloran, K.A. 2012. U.S. national 

forests adapt to climate change through science-management partnerships. 

Climatic Change. 110: 269–296. 

Louter, D. 2006. Windshield wilderness: cars, roads, and nature in Washington’s 

national parks. Seattle, WA: University of Washington Press. 240 p.
106

general technical report pnw-gtr-892

MacArthur, J.; Mote, P.; Ideker, J. [et al.]. 2012. Climate change impact 

assessment for surface transportation in the Pacific Northwest and Alaska. 

Research Report WA-RD 772. Olympia, WA: State of Washington, Department 

of Transportation, Office of Research and Library Services. OTREC-RR-12-01. 

Salem, OR: Oregon Transportation Research and Education Consortium. 272 p.

Mantua N.; Tohver, I.; Hamlet A.F. 2010. Climate change impacts on streamflow extremes and summertime stream temperature and their possible 

consequences for freshwater salmon habitat in Washington state. Climatic 

Change. 201: 187–223.

Martin, Y.E. 2006. Wildfire disturbance and shallow landsliding in coastal British 

Columbia over millennial time scales: a numerical modeling study. Catena. 

69: 206–219.

McCabe, G.J.; Clark, M.P.; Hay, L.E. 2007. Rain-on-snow events in the western 

United States. Bulletin of the American Meteorological Society. 88: 319–328.

Mickelson, K.E.B. 2009. Impacts of regional climate change on the Pacific 

Northwest white water recreation industry. Seattle: University of Washington. 

41 p. M.S. thesis.

Milly, P.C.D.; Betancourt, J.; Falkenmark, M. [et al.]. 2008. Stationarity is dead: 

Whither water management? Science. 319: 573–574.

Montgomery, D.R. 1994. Road surface drainage, channel initiation, and slope 

instability. Water Resources Research. 30: 1925–1932.

Montgomery, D.R.; Schmidt, K.M.; Greenberg, H.M.; Dietrich, W.E. 2000.

Forest clearing and regional landsliding. Geology. 28: 311–314.

Moore, R.; Carey, J.M.; McInnes, R.G. 2010. Landslide behaviour and climate 

change: predictable consequences for the Ventnor Undercliff, Isle of Wight. 

Quarterly Journal of Engineering Geology and Hydrogeology. 43: 447–460. 

Morris, D.; Walls, M. 2009. Climate change and outdoor recreation resources 

for the future: background. Washington, DC: Resources for the Future. 26 p. 

http://www.rff.org/RFF/Documents/RFF-BCK-ORRG_ClimateChange.pdf.

(29 October 2012). 

Mote, P.W.; Hamlet, A.F.; Salathé, EP. 2008. Has spring snowpack declined in 

the Washington Cascades? Hydrology and Earth System Science. 12: 193–206. 

Mote, P.W.; Salathé, E.P. 2010. Future climate in the Pacific Northwest. Climatic 

Change. 102: 29–50.
107

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

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, United Kingdom, and New York: Cambridge University 

Press. 559 p.

National Environmental Policy Act of 1969 [NEPA]; 42 U.S.C. 4321 et seq.

Neary, D.G.; Ryan, K.C.; DeBano, L.F., eds. 2005. Rev. 2008. Wildland fire in 

ecosystems: effects of fire on soils and water. Gen. Tech. Rep. RMRS-GTR42-vol.4. Ogden, UT: U.S. Department of Agriculture, Forest Service, Rocky 

Mountain Research Station. 250 p.

Pelto, M.S.; Riedel, J. 2001. Spatial and temporal variations in annual balance of 

North Cascade glaciers, Washington 1984–2000. Hydrological Processes. 15: 

3461–3472.

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al.]. 2011. Responding to climate 

change in national forests: a guidebook for developing adaptation options. Gen. 

Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 109 p.

Rice, J.; Tredennick, A.; Joyce, L.A. 2012. Climate change on the Shoshone 

National Forest, Wyoming: a synthesis of past climate, climate projections, and 

ecosystem implications. Gen. Tech. Rep. RMRS-GTR-274. Fort Collins, CO: 

U.S. Department of Agriculture, Forest Service, Rocky Mountain Research 

Station. 60 p.

Safe, Accountable, Flexible, Efficient Transportation Equity Act of 2005

[SAFETEA-LU]; 23 U.S.C. 101 note. 

Salathé, E.P.; Leung, L.R.; Qian, Y.; Zhang, Y. 2010. Regional climate model 

projections for the State of Washington. Climatic Change. 102: 51–75.

Sarikhan, I.Y.; Stanton, K.D.; Contreras, A. [et al.]. 2008. Landslide 

reconnaissance following the storm event of December 1–3, 2007, in Western 

Washington. Open File Rep. 2008-5. Seattle: Washington Department of Natural 

Resources. 16 p. http://www.dnr.wa.gov/Publications/ger_ofr2008-5_dec2007_

landslides.pdf. (29 October 2012).

Schmidt, K.; Roering, J.J.; Stock, J.D. [et al.]. 2001. The variability of root 

cohesion as an influence on shallow landslide susceptibility in the Oregon Coast 

Range. Canadian Geotechnical Journal. 38: 995–1024.
108

general technical report pnw-gtr-892

Schuster, R.L.; Highland, L.M. 2003. Impact of landslides and innovative 

landslide-mitigation measures on the natural environment. In: Lee, C.F.; Tham, 

L.G. Proceedings of the international conference on slope engineering. Hong 

Kong, China: University of Hong Kong: 64–74.

Snover, A.K.; Whitely-Binder, L.; Lopez, J. [et al]. 2007. Preparing for climate 

change: a guidebook for local, regional, and state governments. Seattle: 

University of Washington, Climate Impacts Group; King County; ICLEI–Local 

Governments for Sustainability.

Stynes, D.J. 2011. Economic benefits to local communities from national park 

visitation and payroll, 2010. Natural Resour. Rep. NPS/NRSS/EQD/NRR—

2011/481. Fort Collins, CO: U.S. Department of the Interior, National Park 

Service, Natural Resource Stewardship and Science. 42 p. http://www.nature.nps.

gov/socialscience/docs/NPSSystemEstimates2010.pdf. (13 August 2013).

Sumioka, S.S.; Kresch, D.L.; Kasnick, K.D. 1998. Magnitude and frequency of 

floods in Washington. Water-Resources Investigations Rep. 97-4277. Tacoma, 

WA: U.S. Department of the Interior, Geological Survey. 91 p.

Swanson, F.J.; Dyrness, C.T. 1975. Impact of clear-cutting and road construction 

on soil erosion by landslides in the western Cascade Range, Oregon. Geology. 3: 

393–396. 

Swanston, D.N. 1971. Principal mass movement processes influences by logging, 

road building and fire. In: Krygier, J.T.; Hall, J.D., eds., Forest land uses and 

stream environment: proceedings of a symposium. Corvallis, OR: Oregon State 

University: School of Forestry; Department of Fisheries and Wildlife: 29–40.

Swanston, D.N. 1976. Erosion processes and control methods in North America. 

In: Proceedings: 16. IUFRO World Congress, Div I: Forest environment and 

silviculture. Aas, Norway: Norwegian IUFRO Congress Committtee: 251–275. 

http://andrewsforest.oregonstate.edu/pubs/pdf/pub505.pdf. (29 October 2012).

Transportation Research Board [TRB]. 2008. Potential impacts of climate 

change on U.S. transportation. Transportation Research Board Special Rep.

290. Washington, DC: National Academy of Sciences, National Research 

Council of the National Academies. http://onlinepubs.trb.org/onlinepubs/sr/sr290.

pdf. (29 October 2012).
109

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Tohver, I.; Hamlet, A.F.; Lee, S. [In press]. Impacts of 21st century climate 

change on hydrologic extremes in the Pacific Northwest region of North 

America. J. American Water Resources Association. 

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010a. National 

visitor use monitoring results: USDA Forest Service national summary report. 

http://www.fs.fed.us/recreation/programs/nvum/nvum_national_summary_

fy2009.pdf. (30 October 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010b. 

Environmental assessment: Suiattle access and travel management: Mt. 

Baker-Snoqualmie National Forest. http://www.fs.fed.us/nepa/fs-usda-pop.

php/?project=24529. (30 October 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2011a. National 

roadmap for responding to climate change. USDA Forest Service FS-957b. 

http://www.fs.fed.us/climatechange/pdf/Roadmapfinal.pdf. (30 April 2013).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2011b.

Mt. Baker-Snoqualmie national forest fiscal year 2009 monitoring report.

http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/stelprdb5339999.pdf.

(30 October 2012). 

U.S. Department of Agriculture, Forest Service ]USDA FS]. 2011c.

Mt. Baker-Snoqualmie National Forest road maintenance plan summary. 

MBS-RMP-2011. http://www.fs.usda.gov/Internet/FSE_DOCUMENTS/

stelprdb5331506.pdf. (30 October 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012a. Final 

planning rule for National Forest System land management planning. http://www.

fs.usda.gov/detail/planningrule/home/?cid=stelprdb5359471. (30 April 2013).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012b. Granite 

Creek Road decommissioning and road to trail project: environmental 

assessment. Mt. Baker-Snoqualmie National Forest. November 2010. 

http://www.fs.fed.us/nepa/fs-usda-pop.php/?project=37099. (30 April 2013).

U.S. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management [USDA and USDI] 1994a. 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. 
110

general technical report pnw-gtr-892

U.S. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management [USDA and USDI]. 1994b. Standards 

and guidelines for management of habitat for late-successional and old-growth 

forest related species within the range of the northern spotted owl. In: 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]. 

Attachment A. 

U.S. Department of the Interior, National Park Service [USDI NPS]. 1995. 

Final general management plan/environmental impact statement for Lake Chelan 

National Recreation Area. NPS D-174A. Denver, CO: U.S. Department of the 

Interior, National Park Service, Denver Service Center. 493 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2001. 

Mount Rainier National Park: final general management plan environmental 

impact statement. http://www.nps.gov/mora/parkmgmt/upload/moragmp.pdf. 

(30 October 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2010a.

National Park Service climate change response strategy. Fort Collins, CO: 

National Park Service, Climate Change Response Program. 28 p. http://www.nps.

gov/orgs/ccrp/upload/NPS_CCRS.pdf. (30 April 2013).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2010b. 

Lake Chelan National Recreation Area: environmental assessment: Stehekin 

winter ferry landing improvement project. http://parkplanning.nps.gov/document.

cfm?parkID=327&projectID=24737&documentID=32530. (30 April 2013).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2011. 

Ross Lake National Recreation Area final general management plan and 

environmental impact statement. North Cascades National Park Complex. 

http://www.nps.gov/noca/parkmgmt/rlna-gmp.htm. (30 October 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2012a. 

Final Stehekin River Corridor implementation plan/environmental impact 

statement for Lake Chelan National Recreation Area. North Cascades National 

Park Complex. http://parkplanning.nps.gov/projectHome.cfm?projectId=20331. 

(30 April 2013). 
111

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

U.S. Department of the Interior, National Park Service [USDI NPS]. 2012b. 

Foundation document: North Cascades National Park Complex. http://

parkplanning.nps.gov/document.cfm?parkID=327&projectID=16940&document

ID=35271. (30 October 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2012c.

Ross powerhouse rockslide stabilization environmental assessment. 62 p. http://

parkplanning.nps.gov/document.cfm?parkID=327&projectID=36936&document

ID=46342. (30 April 2013).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2012d.

Nisqually to Paradise road rehabilitation project. Mount Rainier National Park. 

http://parkplanning.nps.gov/projectHome.cfm?projectID=26061. (30 October 

2012).

Walder, J.S.; Driedger, C.L. 1994. Rapid geomorphic change caused by 

glacial outburst floods and debris flows along Tahoma Creek, Mount Rainier, 

Washington, U.S.A. Arctic and Alpine Research. 26: 319–327.

Walker, L.; Figliozzi, M.; Haire, A.; MacArthur, J. 2011. Identifying surface 

transportation vulnerabilities and risk assessment opportunities under climate 

change: case study in Portland, Oregon. Transportation Research Record. Journal 

of the Transportation Research Board. 2244: 41–49.

Washington State Department of Transportation [WSDOT]. 2011. 

Climate impacts vulnerability assessment. Report. Olympia, WA: 

Washington Department of Transportation. http://www.wsdot.wa.gov/

NR/rdonlyres/B290651B-24FD-40EC-BEC3-EE5097ED0618/0/

WSDOTClimateImpactsVulnerabilityAssessmentforFHWAFinal.pdf.

(30 April 2013).

Washington State Department of Natural Resources [WDNR]. 2012.

Landslide table from the January 2009 storm event. http://www.dnr.wa.gov/

ResearchScience/Pages/PubData.aspx. (30 April 2013).

Wu, T.; Merry, C. 1990. Slope stability in the transient snow zone. TFWSH15-90-001. Olympia, WA: Washington Department of Natural Resources. 

46 p.
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Introduction

In the Pacific Northwest (PNW), decades of research on the effects of climatic 

variability and change on vegetation dynamics provide a foundation for understanding potential consequences of climate change and options for adapting vegetation 

management. The effects of climate change on vegetation depend on the magnitude 

of changes in climate (i.e., exposure), as well as the sensitivity of species and ecological processes to these changes. Exposure and sensitivity combined determine 

vulnerability (Parry et al. 2007) of vegetation to climate change, and this vulnerability can be reduced depending on the capacity of species to adapt to changes (i.e., 

adaptive capacity) (Parry et al. 2007). Resource management agencies can reduce 

vulnerability depending on the extent to which they can adapt vegetation management practices as climate changes. 

The North Cascadia Adaptation Partnership (NCAP) held a 2-day workshop 

to assess vulnerability of vegetation in the North Cascades to climate change and 

develop adaptation options to reduce vulnerability. The goal of the workshop was 

to convene scientists and land managers concerned about climate change effects on 

vegetation in the NCAP region with a focus on national forests and national parks. 

More than 35 people participated in the workshop, including resource managers and 

scientists from the national parks and forests in the NCAP; University of Washington Climate Impacts Group; U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station; Washington Department of Natural Resources 

(WADNR); City of Seattle; U.S. Environmental Protection Agency; and U.S. Fish 

and Wildlife Service (USFWS). The workshop had four objectives:

• Identify key sensitivities of vegetation and ecological disturbances to

projected changes in climate.

1 Jeremy S. Littell is a research scientist, U.S. Department of the Interior, Alaska Climate 

Center, 4210 University Drive, Anchorage, AK 99508 (formerly research scientist, University of Washington, College of the Environment, Climate Impacts Group, Seattle, WA);

Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle City 

Light, 700 5th Avenue, Seattle, WA 98124 (formerly research biologist, U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire 

Sciences Laboratory, Seattle, WA 98103); Regina M. Rochefort is a science advisor, North 

Cascades National Park Complex, Sedro-Woolley, WA 98284; and Stephen L. Klein is a 

research forester, U.S. Environmental Protection Agency, Western Ecology Division, 200 

SW 35th Street, Corvallis, OR 97333.

Chapter 5: Climate Change and Vegetation in the North 

Cascade Range

Jeremy S. Littell, Crystal L. Raymond, Regina M. Rochefort, and Stephen L. Klein1
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• Review current vegetation management objectives and practices and share 

management approaches that already consider climatic variability or 

change.

• Use the latest scientific information on climate change and its effects on 

vegetation and ecological disturbances to identify adaptation options that 

can be implemented in the region.

• Identify opportunities to work collaboratively to develop adaptation options 

that cross jurisdictional boundaries in the North Cascades.

The workshop included an overview of the latest science on climate change 

effects on vegetation, fire regimes, insects, pathogens, and invasive species. 

Resource managers presented information on current management programs and 

practices for silviculture, forest restoration, fire, invasive species, rare and sensitive 

species, and inventory and monitoring.

During the workshop, scientists and resource managers worked collaboratively 

to identify key sensitivities of vegetation and ecological disturbances that will 

challenge management of vegetation as climate changes. Sensitivities of greatest 

concern to the workshop participants were those associated with increasing rates of 

fire, insect, and pathogen disturbances, as well as the potential for increased spread 

of invasive species. Workshop participants also focused on subalpine and alpine 

zones because the forests, wetlands, and meadows in these zones are likely to be 

sensitive to reduced snowpack,2

 warmer temperatures, and longer growing seasons. 

The second day of the workshop focused on adaptation, with an overview of adaptation principles (Peterson et al. 2011b) and examples of adapting vegetation management at the Olympic National Forest and Olympic National Park (Halofsky et al. 

2011). Scientists and resource managers identified options for adapting vegetation 

management to reduce adverse effects of climate change. The initial vulnerability 

assessment and adaptation planning in the workshop were refined with further 

discussions with scientists and resource managers.

In this chapter, we describe current vegetation in the North Cascades, projected 

changes in climate relevant to vegetation, and pathways through which climate will 

affect vegetation and disturbances in the North Cascades. We summarize the current framework for managing vegetation and disturbances in the national parks and

2 Snowpack is measured as snow depth or snow water equivalent (SWE), the water content 

of the snowpack. For comparisons, SWE on April 1 is commonly used because it corresponds to the date of peak SWE in many areas and is correlated with summer water supply 

in the PNW. Timing of snowmelt in spring can also be an important indicator of wildlife 

habitat and ecosystem processes (see chapter 4 of this report for a detailed discussion of 

snowpack).
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forests in the NCAP. Lastly, we summarize the potential changes in these management practices to facilitate adaptation options that were identified by workshop 

participants. 

Current Vegetation in the North Cascades

The current distribution of vegetation in the North Cascades is a function of the 

biophysical environment, a mix of factors associated with climate, topography, 

soils, and disturbances. Physiological tolerances of individual tree species to these 

environmental factors (McKenzie et al. 2003), as well as competition and disturbances, control the distribution of tree species. Forests are predominantly coniferous with deciduous species growing in riparian corridors and as secondary species 

in the understory (fig. 5.1). Some deciduous species also grow as late-successional 

species in avalanche paths at high elevations and in low-elevation areas that have 

been harvested and lack a seed source for conifer species. Mild, maritime climate 

and limited disturbance at low elevations west of the Cascade crest enable growth 

of dense forests of long-lived, shade-tolerant coniferous species. At higher elevations, colder winters and more snowpack favor a different mix of coniferous 

species, and these subalpine forests are generally less dense with smaller trees. At 

the highest elevations near treeline, tree growth and forest distribution are limited 

by cold winter temperatures, short growing seasons, and harsh physical conditions 

(such as avalanches and wind). 

Climate east of the Cascade crest transitions from maritime to continental 

with drier, warmer summers with lower soil moisture and colder winters. At the 

lowest elevations, fire is frequent and soil moisture in summer is low, so forests 

are dominated by ponderosa pine (Pinus ponderosa var. ponderosa Douglas ex P. 

Lawson & C. Lawson) and transition into sagebrush (Artemisia tridentata Nutt.) 

steppe and grasslands to the east (fig. 5.1). At middle elevations and in the absence 

of fire, ponderosa pine forests transition to denser, mixed-conifer forests. At higher 

elevations and in the north-eastern Cascades, subalpine and montane mixed-conifer 

forests dominate because winters are colder and snow depth and duration are 

greater. The mix of conifer species growing in these subalpine and montane forests 

differs from those in high-elevation forests of the western Cascades because summers are drier and fire is more frequent. Moisture availability, as well as persistent 

snowpack and a short growing season, limit the distribution of some species.

Forest ecosystems dominate much of the North Cascades (fig 5.1), but several 

nonforest ecosystems are ecologically important for critical habitat and contribute 

to the character of wilderness and recreational opportunities in the national forests 

and national parks, particularly in the alpine and subalpine zones. Together, these 
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zones comprise an ecotone spanning the area between closed-canopy forest (forest 

line) and permanent snow and ice or rocky mountain tops. Snowpack, temperature, 

and topography are the primary determinants of vegetation distribution, structure, 

and composition in these systems (Douglas and Bliss 1977, Holtmeier and Broll 

2005, Malanson et al. 2007). Snow cover both defines the length of the growing 

season and provides most of the available moisture for plant growth during the dry 

summers (Canaday and Fonda 1974, Douglas 1970, Henderson 1974). Despite harsh 

environmental conditions, alpine and subalpine vegetation communities are spatially heterogeneous as a result of the steep gradients in soil moisture, temperature, 

and growing season length associated with topographic variation (Crawford et al. 

2008).

Figure 5.1—Dominant (by land area) vegetation types in the Northern Cascade Range. Data: U.S. 

Geological Survey National Gap Analysis Program. 
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The subalpine parkland is a mosaic of tree islands, ericaceous dwarf-shrubs, 

forbs, and grasses (Douglas 1970, Franklin and Dyrness 1988, Henderson, 1974). 

Tree species within the zone are similar to the montane forest below. From west to 

east across the Cascade crest, meadow species composition transitions from lush, 

continuous cover of forbs and sedges to patchy bunchgrass (e.g., greenleaf fescue 

[Festuca viridula Vasey]) and forb associations of the drier east slopes. Vegetation 

in the alpine zone is generally sparsely distributed and includes patches of sedgeturf communities, subshrubs (e.g., heather species), talus slopes, and fellfields 

(Douglas and Bliss 1977, Edwards 1980). High-elevation wetlands range from 

small, ephemeral ponds and wet meadows to open water lakes and provide important habitats for wildlife and ecosystem services such as nutrient cycling, water 

storage and filtration, and carbon sequestration (IPCC 2007).

Elevations of forest line and tree line vary with latitude and aspect, reflecting 

differences in mean seasonal temperatures across the rugged topography of the 

Cascade Range (Körner and Paulsen 2004). In the northern portion of the North 

Cascades, continuous forest ends at 1280 m on northern slopes and 1580 m on 

southern slopes (Douglas 1972, Douglas and Bliss 1977). At the southern end of the 

region, forest line ranges from 1646 m on the southern slopes of Mount Rainier to 

1951 m on the drier east side. 

Projected Changes in Regional Climate Relevant to 

Vegetation

Projected changes in regional temperature and precipitation (chapter 3) (Mote 

and Salathé 2010) are related to the physical and hydrologic conditions that affect 

vegetation function and life history (Littell et al. 2010). Changes in temperature 

and precipitation will interact to affect local snowpack development and timing 

of snowmelt, but snowpack is likely to decrease and melt earlier, particularly at 

low elevations where most snow falls close to freezing temperatures (chapter 4). 

Changes in climate are projected at regional to subregional (smaller than 100 km) 

scales, but vegetation response at local scales (smaller than 10 km) will also be 

affected by local factors (e.g., topography, competition, and physical effects of other 

species). These local factors tend to mediate or exacerbate changes in regional or 

subregional climate. 

Vegetation will experience the integrated effects of changes in temperature, 

precipitation, and snowpack. Thus when assessing the effects of climate change on 

vegetation, it can be beneficial to consider climatic variables that integrate temperature, precipitation, and snowpack to provide a better indication of the changes in 

moisture and energy availability that plants will experience. 

Vegetation will 

experience the 

integrated effects 

of changes in 

temperature, 

precipitation, and 

snowpack.
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Soil moisture is one indication of the water available to vegetation. Based on 

current projections of no increase in summer precipitation, warmer temperatures 

(chapter 4), and declining snowpack, the North Cascades is expected to experience 

longer periods of low soil moisture in the dry season. Soil moisture on July 1 is 

projected to decline throughout most of the North Cascades, with declines of up 

to 35 percent in much of the region by the 2040s (average of years in the 30-year 

window from 2030 to 2059) (Elsner et al. 2010) (fig. 5.2).

Another measure that integrates temperature and precipitation to indicate 

moisture stress experienced by vegetation is water balance deficit. Water balance 

deficit is a measure of potential vs. actual evapotranspiration of plants. Potential 

evapotranspiration (PET) is the amount of water that could be evaporated from land 

and transpired from plants. Actual evapotranspiration (AET) is the amount of water 

Figure 5.2—Historical (1916–2006) and future (2030–2059 and 2070–2099) July 1 soil moisture 

adapted from Elsner et al. (2010). Soil moisture on July 1 decreases over the NCAP domain toward 

the end of the 21st century. 
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that is evaporated and transpired and it is an index of simultaneous usable water 

and energy for plants (Stephenson 1990). When AET exceeds PET, surplus water is 

typically available for surface runoff or subsurface movement (Stephenson 1990). 

In contrast, when PET exceeds AET (more water could be transpired than is being 

transpired), a water balance deficit exists. 

An increase in temperature also increases potential evapotranspiration (all other 

things being equal), and thus water balance deficit. In the North Cascades, water 

balance deficit in summer is projected to increase east of the Cascade crest, with an 

average increase of 35 mm for the 2040s in Okanogan-Wenatchee National Forest 

(OWNF). Increases and decreases in water balance deficit average out to small (-2 

to -5 mm) decreases by the 2040s west of the Cascade crest (Elsner et al. 2010) (fig. 

5.3). The decrease in water balance deficit (i.e., increase in water supply) is likely 

a result of increased water availability at high elevations where AET is expected to 

increase with earlier snowmelt in spring.

Figure 5.3—Historical (1916–2006) and future (2030–2059, and 2070–2099) June-July-August water 

balance deficit, adapted from Elsner et al. (2010).
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Vegetation is affected by extremes in climate (e.g., windstorms, intense precipitation, droughts, extreme fire weather), as well as averages, and current evidence 

suggests extremes may become more frequent with climate change. Using two 

regional climate models (essentially weather forecasting models driven by global 

climate models [GCM]), Salathé et al. (2010) projected an increase of 7 to 20 

three-day heat waves (a combined index of heat and humidity greater than 32 °C) 

for the North Cascades by the 2040s. Extreme precipitation events are also expected 

to increase, particularly on the western slopes of the Cascades (Salathé et al. 2010), 

because of the influence of topography and the intensified water cycle expected 

with climate change. Despite their ecological importance, changes in climatic 

extremes are difficult to project with simulation models. There are currently no 

projections of future regional drought (duration or magnitude) or wind for the PNW.

Physical Mechanisms for Climatic Effects on Forest Vegetation

The sensitivity of vegetation and the physical mechanisms through which changes 

in climate will affect vegetation vary by location depending on the historical 

climate and current climatic limitations on plant growth and species distributions. 

Direct effects of climate change on vegetation will depend on how climate affects 

limiting factors for vegetation establishment, growth, productivity, and life history. 

Climate change will indirectly affect vegetation by also affecting ecological disturbances and biogeochemistry. Vegetation growth also may be affected by changes 

in atmospheric concentrations of carbon dioxide (CO2), which can affect water 

use efficiency and growth (Law et al. 2002, Oren et al. 2001). We do not focus on 

this mechanism of change in this chapter because of the limited information on 

this effect in the PNW and for natural systems in general, rather than controlled 

experiments.

Plant growth can be seasonally or chronically limited by climate (Churkina and 

Running 1998, Churkina et al. 1999, Nemani et al. 2003). When PET is higher than 

AET (i.e., water deficit), vegetation productivity is limited by water availability. 

Water balance deficit (e.g., Churkina et al. 1999, Stephenson 1990) is correlated 

with the distribution of vegetation (Stephenson 1990). In the PNW, vegetation 

experiences water limitation seasonally, even in the maritime western Cascades, 

because the supply of water and energy are asynchronous. More than 75 percent 

of precipitation falls outside of the growing season (Stephenson 1990, Waring and 

Franklin 1979). When AET is higher than PET, water is not limiting and vegetation productivity is limited by thermal constraints, such as growing degree days or 

Effects of climate 

change on vegetation 

will depend on how 

climate effects limiting 

factors for vegetation 

establishment, growth, 

productivity, and life 

history.
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growing season length (Churkina et al. 1999, Littell et al. 2010). Thermal limitations typically occur at locations and times that water availability is sufficient (e.g., 

maritime PNW forests or tundra), but seasonal water limitations can still limit 

vegetation productivity in these locations. 

It is likely that most low-elevation forests in the North Cascades that currently 

experience chronic or seasonal water limitation will experience more severe or 

longer duration water limitation in the future, given projected increases in July 1 

soil moisture (fig. 5.2) and summer (June through August) water balance deficit 

(fig. 5.3) (Littell et al. 2010). In contrast, current energy-limited forests will likely 

become less energy limited, and the effects of climate change will depend on the 

degree of seasonal water limitation. Short-term effects on water-limited forests will 

likely include decreased seedling regeneration and tree growth, increased mortality 

(especially for seedlings), vulnerability to insects (because of host tree stress), and 

increased area burned by fire (Littell et al. 2010). Short-term effects on energylimited forests will likely include increased seedling establishment and tree growth, 

but also increased area burned by fire and vulnerability to insects because insect 

ranges are projected to expand into forests with historically unfavorable climate 

(Littell et al. 2010).

Vegetation in the alpine treeline ecotone is expected to be sensitive to projected 

changes in climate (Canonne et al. 2007, Holtmeier and Broll 2005, Loarie et al. 

2009). Snowpack in the Cascade Range has already declined by 15 to 35 percent 

since the 1930s (Mote et al. 2005, 2008), and warming temperatures will continue 

to reduce the duration of snow cover and the April 1 snow water equivalent (SWE), 

altering the length of the growing season and available soil moisture (Elsner et al. 

2010). Increased growing season length, warmer air temperatures, and increased 

soil moisture will lower environmental constraints on tree establishment in subalpine meadows. Expansion of tree islands in the subalpine parkland and rising 

treelines may be the most visible changes in high-elevation forests. Palaeoecological studies provide evidence that altitudinal treeline locations have fluctuated 

throughout the Holocene in response to climate, with advances during warm 

periods and retreats during cooler climates (Kearney and Luckman 1983, LaMarche 

1973, Markgraf and Scott 1981, Rochefort et al. 1994). More recent expansion of 

tree islands in subalpine areas has also been observed (Bekker 2005, Harsch et al. 

2009, Klasner and Fagre 2002, Stueve et al. 2009). Species interactions and microtopography interact with climate to influence spatial distribution and periodicity 

of tree establishment (Alftine et al. 2003, Germino et al. 2002, Haugo and Halpern 

2010, Malanson et al. 2007). Near the alpine treeline, local physical drivers such as 

snowpack, wind, radiation, and seasonal desiccation severely limit establishment 
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to the most favorable microsites until limiting factors are ameliorated (Smith et al. 

2009). The area available for forest expansion upslope in the Cascades is limited 

either by available land area at higher elevation or by lack of soil development in 

deglaciating areas.

Shifts in distributions of herbaceous vegetation, shrubs, and sedges, may be less 

visible than shifts in tree line, but observational studies and manipulative experiments suggest significant future changes above tree line (Grabherr et al. 1994, 

Theurillat and Guisan 2001, Walther et al. 2002). Experimental warming of tundra 

plant communities in North America have documented increases in height and 

cover of graminoids and deciduous shrubs and decreased growth of mosses, lichens, 

and forbs (Arft et al. 1999, Chapin et al. 1995, Harte and Shaw 1995, Walker et al. 

2006). Since the 1950s, broad landscape patterns of vegetation in portions of the 

European Alps have changed similar to those indicated by the warming experiments (Cannone et al. 2007). Although there are general trends in the response of 

functional types across many studies, there are also differences between species, 

elevations, and localities.

In Europe, vascular plant species richness on mountain summits has increased 

over the last century as a result of upward plant migrations (Odland et al. 2010, 

Pauli et al. 2007, Walther et al. 2005). As lower elevation species in the Cascades 

move up in elevation, species richness in specific areas may increase, but spatial 

heterogeneity and similarity among summits may decrease, resulting in homogeneity among peaks (Jurasinksi and Kreyling 2007, Odland et al. 2010). Increased species diversity may also include nonnative, invasive species that have been limited 

by abiotic conditions rather than dispersal or disturbance regimes (Pauchard et al. 

2009). It is difficult to project the rate of these changes. Some warming studies 

have documented changes in tundra growth following two seasons of temperature 

increases of 1 to 3 °C (Walker et al. 2006), but others found that 4 years of warming had no effect on subalpine plant community richness or distribution (Price and 

Walker 1998, 2000). The range in results from different experiments may typify 

future changes in the alpine tree line ecotone, because vegetation response is 

influenced by growth-limiting factors, which differ by species, elevation, slope, and 

topography (Chapin and Shaver 1985, Klanderud 2008). These limiting factors may 

also change over time as warmer temperatures increase nutrient availability and 

alter community structure and dynamics (e.g., competition for light) (Chapin et al. 

1995, Klanderud and Totland 2005).
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Climate Change Effects on Biodiversity and Vegetation 

Distribution 

Projected Changes in Vegetation Biomes

Dynamic vegetation models simulate the combined effects of climate, plant tolerances, disturbance, and ecosystem processes (such as hydrology, carbon, and 

nutrient cycles) on vegetation distributions (e.g., Lenihan et al. 2008). These models 

typically project changes in coarse vegetation classifications, rather than individual 

species. Rogers et al. (2011) used the dynamic vegetation model, MC1, to project 

changes in the area of vegetation biomes (e.g., grasslands, shrublands, temperate 

coniferous forests, subalpine forests, and alpine tundra) for the western two-thirds 

of Washington and Oregon, including the North Cascades. The MC1 model projects 

changes in biomes using future climate data from GCMs. Rogers et al. (2011) used 

future climate data from three GCMs and the A1B emissions scenario. Projections 

from MC1 indicate that the distribution of some vegetation biomes may change 

significantly in the North Cascades over the next century (fig. 5.4). Alpine tundra 

almost completely disappears, and the area of subalpine forest decreases significantly across the region for all three climate scenarios (table 5.1). Large areas of 

existing maritime conifer forest on the west slopes of the Cascades are projected to 

shift to drier temperate conifer forest (fig. 5.4). 

The three MC1 projections agree on these regional trends, but they show 

differences in what the historical vegetation shifts to. For example, the projections 

show similar declines in subalpine forest area but differences in the vegetation that 

replaces it. Differences in future projections are mostly caused by differences in 

the seasonal climate and magnitude of changes in precipitation and temperature 

among the three climate scenarios. Projections with climate data from the Hadley 

CM3 GCM (warmest [+4.5 °C] and drier [-5 percent precipitation] in the 2080s) (see 

chapter 3) show the largest decline in maritime evergreen needleleaf forest and the 

largest increase in temperate evergreen needleleaf woodland, temperate evergreen 

needleleaf forest, and temperate shrubland (table 5.1). Projections with climate data 

from the CSIRO GCM (least warming [+3.5 °C] and wettest [+15 percent]) show 

the least change, although substantial areas of maritime and subalpine forest are 

replaced with temperate needleleaf forest (table 5.1). Projections with climate data 

from the MIROC 3.2 GCM (warmest future [+5.0 °C] and little precipitation change 

[-1 percent]) show the smallest increase in temperate needleleaf forest, and much of 

the subalpine forest is replaced by maritime evergreen forest (table 5.1). The MC1 

model assumes an increase in plant water use efficiency with increased atmospheric 

CO2 (Rogers et al. 2011), which ameliorates the effect of lower water availability 
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Figure 5.4—Projected changes in vegetation biomes from the MC1 dynamic global vegetation model. 

Changes are relative to historical conditions (Küchler potential vegetation) for climate scenarios 

from three GCMs (MIROC, Hadley CM3, and CSIRO) under a high (A2) greenhouse gas emissions 

scenario and for the period 2070–2099 (2080s). The CSIRO model is a relatively cooler and wetter 

scenario, Hadley CM3 is a hotter and drier scenario, and MIROC is a hotter and wetter scenario. 

Data source: Rogers et al. (2011) and Databasin.
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Table 5.1(a)–Projected percentage change in area of vegetation biomes for the late 21st century (2070–2099) with the MC1 

dynamic vegetation model and climate data from three global climate models, CSIRO, Hadley CM3, and MIROC 3.2a

Mount Baker–Snoqualmie National Forest Mount Rainier National Park

Vegetation biome

Modeled 

historical CSIROb

Hadley 

CM3c

MIROC 

3.2d

Modeled 

historical CSIROb

Hadley 

CM3c

MIROC 

3.2d

Tundra 1.1 0.2 0.0 0.1 10.6 5.3 2.3 3.5Subalpine forest 13.0 1.2 0.3 0.4 33.4 7.3 4.6 5.0Maritime evergreen needleleaf forest 73.0 62.5 0.0 70.4 54.9 67.8 0.0 84.4Temperate evergreen needleleaf forest 12.9 36.0 95.2 27.5 0.1 19.1 75.2 6.5Temperate cool mixed forest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Temperate warm mixed forest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Temperate evergreen needleleaf woodland 0.0 0.0 3.2 0.3 0.0 0.1 7.0 0.2Temperate shrubland 0.0 0.0 1.1 1.3 0.0 0.1 10.4 0.2Table 5.1(b)—Projected percentage change in area of vegetation biomes for the late 21st century (2070–2099) with the 

MC1 dynamic vegetation model and climate data from three global climate models, CSIRO, Hadley CM3, and MIROC 3.2a

North Cascades National Park Complex Okanogan-Wenatchee National Forest

Vegetation biome

Modeled 

historical CSIROb

Hadley 

CM3c

MIROC 

3.2d

Modeled 

historical CSIROb

Hadley

CM3c

MIROC 

3.2d

Tundra 5.7 0.0 0.0 0.0 3.5 0.0 0.0 0.0Subalpine forest 35.2 8.5 0.6 1.0 29.3 5.4 0.2 0.4Maritime evergreen needleleaf forest 33.3 15.9 0.0 25.5 6.8 5.3 0.0 11.5Temperate evergreen needleleaf forest 25.6 75.4 83.3 69.6 58.1 89.2 87.2 86.9Temperate cool mixed forest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Temperate warm mixed forest 0.0 0.0 0.0 0.0 0.0 0.0 0.0 0.0Temperate evergreen needleleaf woodland 0.0 0.0 10.7 0.7 1.2 0.0 12.2 0.5Temperate shrubland 0.1 0.1 5.3 3.1 1.1 0.0 0.4 0.7a Source: Rogers et al. 2011.b The CSIRO model produces future annual climate with a 3.5 °C increase in temperature and a 15 percent increase in precipitation (Littell et al. 2011).c The Hadley CM3 model produces future annual climate with a 4.5 °C increase in temperature and a 5 percent decrease in precipitation (Littell et al. 2011).d The MIROC 3.2 model produces future annual climate with a 5.0 °C increase in temperature and a 1 percent decrease in precipitation (Littell et al. 2011).
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on projected changes in vegetation distributions. The scientific literature disagrees 

about the degree to which water use efficiency will increase and offset lower plant 

productivity associated with lower water availability (Law et al. 2002, Oren et al. 

2001).

Projected Changes in Climatic Suitability for Tree Species 

Both quantitative (correlative) and qualitative (subjective vulnerability indices) have 

been used to evaluate the potential effects of climate change on forest and nonforest species distributions in the PNW. Projected effects of climate change on tree 

species in the PNW suggest widespread changes in equilibrium vegetation. Vulnerability assessments using process models (e.g., Coops and Waring 2011) and current 

factors indicating general biogeographic vulnerability of species (e.g., Aubry et 

al. 2011) indicate substantial risk for many species. Statistical models of speciesclimate relationships (e.g., McKenzie et al. 2003) show that tree species have unique 

climatic tolerances and thus climate change will affect them differently depending 

on their tolerances (McKenney et al. 2011; Rehfeldt et al. 2006, 2008). 

Species-climate relationships have been used to project future favorable climate 

for species in western North America (McKenney et al. 2007, 2011; Rehfeldt et 

al. 2006, 2008) and in Washington (e.g., Littell et al. 2010). Climate is projected 

to become unfavorable for Douglas-fir (Pseudotsuga menziesii [Mirb.] Franco) in 

more than 32 percent of its current range in Washington (Littell et al. 2010) (fig. 

5.5). For pine species in Washington, 15 percent of the current range will remain 

climatically suitable for all pine species, whereas 85 percent will be outside the climatically suitable range for one or more current pine species (Littell et al. 2010) (fig. 

5.5). Coops and Waring (2010), using a single GCM (CCSM2) and a process model 

(3PG), also projected that the range of lodgepole pine (Pinus contorta var. latifolia

Engelm. ex S. Watson) will likely decrease in the PNW. Rehfeldt et al. (2006) found 

comparable changes in future lodgepole pine distribution using multiple models 

(fig. 5.6). McKenney et al. (2011) summarized species responses across western 

North America and found that the change in total tree species in the PNW is often 

near balance (-5 to +10 species) or a loss of 6 to 20 species, but some scenarios have 

subregional losses of 21 to 38 species. 

Modeling species-climate relationships is a useful approach to understand the 

potential effects of climate change on biogeography, particularly because a focus 

solely on vegetation biomes may mask important changes in species dominance. 

The models are useful indicators of where or when climatic variables may begin to 

exceed species tolerances. However, most statistical models of species-climate relationships assume climate is the primary determinant of species presence or absence 

Projected effects of 

climate change on tree 

species in the Pacific 

Northwest suggest 

widespread changes

in vegetation.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Figure 5.5—Changes in climatic suitability for multiple pine species (left) and Douglas-fir (right), based on climate 

correlations with current species distributions. Data: Rehfeldt et al. (2006), analysis after Littell et al. (2010). 

Figure 5.6—Historical (left) and 2060s (2050–2079) changes in climatic suitability for lodgepole pine, based on 

climate correlations with current species distributions. Data: Rehfeldt et al. (2006), analysis after Littell et al. (2010).
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and do not incorporate ecological interactions (e.g., competition), disturbance, 

and species traits (including autecological characteristics) that predispose species 

vulnerability to climate (Aubry et al. 2011). 

Changes in Distribution of Rare Plant Species 

The North Cascades is home to several rare vascular and nonvascular plants, many 

of which have common traits that make them vulnerable to climate change. They 

typically grow under narrow environmental conditions and are often at the margins 

of their distributions where expansions and contractions are most likely to occur. 

Several rare plants are growing at the southern extent of their ranges and are more 

common farther north in southeastern Alaska or Haida Gwaii. Others occupy cold 

microclimates with wet soils or high-elevation meadows and wetlands, microhabitats that could be more susceptible to warmer temperatures, drier summers, and 

reduced snowpack.

Climate Change Effects on Ecological Disturbances

Insects

Most native forest insects cause patchy defoliation or tree mortality when conditions 

promote insect survival and undermine natural defenses of trees. Recent warming 

has affected population dynamics of the native mountain pine beetle (Dendroctonus ponderosae Hopkins) in colder parts of its range in British Columbia and the 

Rocky Mountains. Warming has reduced thermal migration barriers and fatally 

low winter temperatures, and synchronized populations to one life cycle per year 

in areas where the time required for each generation was longer historically (e.g., 

Logan and Powell 2001). Increased vulnerability of hosts caused by moisture stress 

and tree age were also factors driving the widespread outbreaks observed in these 

regions. The mountain pine beetle has significantly affected forests in the North 

Cascades, although the outbreaks have not been as large or continuous as in other 

parts of the Western United States and Canada. In the North Cascades, it is likely 

that higher winter temperatures have also relaxed thermal limitations on population 

size, but tree vulnerability resulting from moisture stress and high stand density 

are also important controls of recent outbreaks. Based on aerial detection surveys 

by the U.S. Department of Agriculture Forest Service (USDA FS) and Washington Department of Natural Resources, the 30-year trend in mountain pine beetle 

mortality shows increases in both lodgepole pine and whitebark pine (P. albicaulis

Engelm.) forests (fig. 5.7), although surveys in 2010 and 2011 detected decreases 

(WADNR 2012a). These recent decreases are likely caused by the combined effects 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

of above-average precipitation, below-average temperatures in spring, and previous 

mortality of the most vulnerable host trees in affected stands (WADNR 2012a). 

Aerial detection surveys between 1980 and 2011 show large areas of mortality from other host-specific bark beetles and defoliators. The eastern slopes of 

the Cascades are experiencing increases in the area and severity of defoliation by 

western spruce budworm (Choristoneura occidentalis Freeman) (fig. 5.8), although 

a 20-year outbreak in the southern Cascade Range of Washington has recently 

Figure 5.7—Mountain pine beetle mortality recorded from aerial surveys in the North Cascades from 

1980 to 2012. Data: courtesy of A. Dozic, annual aerial survey, Washington Department of Natural 

Resources, Resource Protection Division, Forest Health; U.S. Forest Service, Forest Health Protection; and Oregon Department of Forestry, Forest Health Management. Map concept from A. Dozic.
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subsided (WADNR 2012a). Maritime forests of the western Cascades experienced 

recent outbreaks of Douglas-fir beetle (Dendroctonus pseudotsugae Hopkins), fir 

engraver (Scolytus ventralis LeConte), and western balsam bark beetle (Dryocoetes 

confusus Swaine), but outbreaks appear to be ending with the area affected declining in recent years (WADNR 2012a). The North Cascades are experiencing a new 

outbreak of western hemlock looper (Lambdina fiscellaria lugubrosa Hulst) in 

old western hemlock (Tsuga heterophylla [Raf.] Sarg.) forests (WADNR 2012a). 

Figure 5.8—Western spruce budworm defoliation recorded from aerial surveys in the North 

Cascades from 1980 to 2010. Data: courtesy of A. Dozic, annual aerial survey, Washington 

Department of Natural Resources. U.S. Forest Service, Forest Health Protection; Protection 

Division, Forest Health; and Oregon Department of Forestry, Forest Health Management. Map 

concept from A. Dozic.
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Tree mortality caused by the balsam woolly adelgid (Adelges piceae Ratzeburg), 

a nonnative insect that affects fir species, has also increased throughout the North 

Cascades in the last 30 years (WADNR 2012a).

All of these insects have relationships with seasonal weather conditions, but 

currently only the mountain pine beetle, western spruce budworm, and spruce 

beetle (Dendroctonus rufipennis Kirby) have well-documented relationships with 

climate (Bentz et al. 2010, Hicke et al. 2006, Littell et al. 2010). As temperatures 

increase, habitat that was previously unsuitable for the mountain pine beetle will 

likely become suitable (Hicke et al. 2006, Littell et al. 2010), exposing pine trees at 

high elevations to new outbreaks. By the end of the 21st century, the total habitat for 

the mountain pine beetle in Washington will decline under some scenarios (Hicke 

et al. 2006), but not before it has had decades to expand its range (Bentz et al. 2010, 

Littell et al. 2010) (fig. 5.9). The timing of bud break in Douglas-fir and grand fir 

(Abies grandis [Douglas ex D. Don] Lindl.), which is linked to soil temperature, can 

greatly affect the survival of western spruce budworm. If bud swelling occurs later 

in the season and is not synchronized with insect emergence, budworm survival 

will decline. In addition, survival can be reduced by warmer fall temperatures and 

atypical fall or spring frosts outside the period of insect dormancy.

Fire Regimes

Area burned by wildfire in PNW forests is sensitive to climate (Littell et al. 2009, 

2010; McKenzie et al. 2004), but the most important climatic mechanisms and 

the sensitivity to climate differ by forest type (Littell et al. 2009, 2010). Before 

Euro-American settlement and in the first half of the 20th century, the area burned 

both east and west of the Cascade crest was probably much larger than what has 

been observed in recent decades. Fires of many hundreds of thousands of hectares 

burned in the western Cascades in the 1700s (Henderson et al. 1992). Generally, 

warmer and drier summers precondition PNW forests by drying available fuels 

over large areas (Littell et al. 2010). The occurrence of fire ignitions may be 

equally related to low spring snowpack (Cansler 2011) in some forests in the North 

Cascades.

Between 1980 and 2006, the area burned by fire varied by ecoregion (fig. 5.10), 

and during this period, the relationship between area burned and climate was 

stronger in the eastern Cascades, where fuels are more likely to dry sufficiently 

to carry fire. In the western Cascades, the area burned was lower because a rare 

combination of prolonged drought, high temperature, high wind, and low humidity 

was required to dry fuels sufficiently to sustain the spread of a large fire.

As temperatures 

increase, habitat 

that was previously 

unsuitable for the 

mountain pine beetle 

will likely become 

suitable.
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5.9—Historical (1971–2000) probability of climatically suitable habitat for the mountain pine beetle 

in the North Cascades and changes for the 2030s (2001–2030) and 2080s (2071–2100) using SRES 

A2 emissions and the CNCRM3 global climate model. For the historical period, probability values 

reflect the product of the probability of adaptive seasonality and cold survival, with high values 

(closer to 1) indicating climatically more suitable habitat and low values (closer to zero) indicating climatically less suitable habitat. For changes in the 21st century, positive values (red) indicate 

increases in suitability compared to historical and negative values (green) indicate decreases. Data: 

Bentz et al. (2010). 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Climate change will almost certainly increase area burned by fire (Littell et 

al. 2010) and biomass consumed in PNW forests (Raymond and McKenzie 2012). 

Based on statistical climate-fire modeling (average of two GCMs [CGCM3 and 

ECHAM5] for A1B emissions), area burned by wildfire in the PNW (Washington, Oregon, Idaho, and western Montana) is projected to be 0.3 million ha in the 

2020s, 0.5 million ha in the 2040s, and 0.8 million ha in the 2080s (Littell et al. 

2010). The probability of exceeding the 95th percentile area burned for the period 

1916–2006 increases from 5 to 48 percent by the 2080s (Littell et al. 2010). The area 

burned is expected to increase on average by a factor of 3.8 in forested ecosystems 

(Western and Eastern Cascades, Okanogan Highlands, Blue Mountains) compared 

to 1980–2006 (fig. 5.11). Using the MC1 dynamic vegetation model, Rogers et al. 

(2011) projected increases in area burned of 76 to 310 percent (fig. 5.12), depending on alternative scenarios for climate and fire suppression. Climate scenarios 

included data from three GCMs (CSIRO, MIROC 3.2, and Hadley CM3) and a high 

(A2) emissions scenario.

In addition to annual area burned, the frequency, size, and severity of individual fires in the North Cascades also could change in a warmer climate. Warmer 

July temperatures are significantly correlated with increasing severity (Cansler 

2011), and burn severity is projected to increase 29 to 41 percent by 2100, compared 

to 1971–2000 (Rogers et al. 2011). However, relative to annual area burned, less 

quantitative information is available on how fire severity will respond to changes in 

climate. 

Figure 5.10—Area burned in the western and eastern Cascades (Washington and Oregon), 1980–

2009. The data from 2010 were provisional at the time of analysis. Data: Littell and Gwozdz (2011).

Climate change will 

almost certainly 

increase area burned 

by fire and biomass 

consumed in Pacific 

Northwest forests.
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Figure 5.11—Expected changes in area burned for scenarios of future climate and hydrology in 

the western and eastern Cascades (Bailey ecosections). The B1 scenario represents less warming 

with lower greenhouse gas emissions. The A1B scenario represents more warming with higher 

greenhouse gas emissions, and is the highest average of the SRES scenarios until the 2040s. The area 

burned in both ecosections increases substantially, but the rate of increase is higher in the western 

Cascades than the eastern Cascades. Numbers beneath the box indicate the average annual area 

burned for the historical period and three future periods (Littell et al. 2010).

Figure 5.12—Changes in cell fraction area burned from the MC1 dynamic global vegetation model. 

Data: Databasin (Rogers et al. 2011). 
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The effects of climate change on forest vegetation will also depend on the 

degree to which fire exclusion has affected forest density and fuels (Hessburg et al. 

2005), particularly in forests that had low- to moderate-severity fires regimes before 

Euro-American settlement. In these forests where tree density and ladder fuels have 

increased because of fire exclusion, this forest structure will exacerbate climatedriven increases in area burned and severity of burns. In forests where mixed- and 

high-severity fires with longer fire return intervals (50 to 100 years) dominated the 

landscape (e.g., lodgepole pine stands, subalpine forests, and west-side Douglas-fir), 

increases in area burned may lead to larger, more homogeneous patches preconditioned for future fires (Perry et al. 2011). Fire return intervals in maritime forests 

of the western Cascades are long enough (more than 100 years) that fire suppression has not affected forest structure (Agee 1993) and changes in fire regimes will 

primarily be driven by changes in climate. 

Forest Pathogens

Climate influences pathogen range and survival, host vulnerability, and hostpathogen interactions, but potential effects of climate change on pathogens are 

uncertain. Root rot pathogens could increase because of stressed host trees (climate or other stressors) (Chmura et al. 2011), and Armillaria in Douglas-fir could 

increase in a warmer climate (Klopfenstein et al. 2009). Foliage fungi, such as 

Swiss needle cast (Phaeocryptopus gaeumannii [T. Rhode] Petr.) (Chmura et al. 

2011) appear to be affected by spring and summer precipitation. However, making 

generalizations about climate-pathogen relationships is difficult because those 

relationships are likely to be species- and host-specific.

Kliejunas (2011) evaluated the relative risk of disease damage in forests of 

the Western United States by combining the likelihood of increased damage and 

the consequences of damage for several pathogen species. Risk potential depends 

on the disease and climate scenario (warmer, wetter vs. warmer, drier). By 2100, 

Cytospora canker of alder, dwarf mistletoes (Arceuthobium spp.), and Alaska 

yellow-cedar decline would have high risk. In a warmer, drier climate, Armillaria

is expected to have very high risk. In a warmer, wetter climate, Armillaria and 

dwarf mistletoe are expected to have high risk, and sudden oak death (Phytophthora 

ramorum Werres et al.) would have very high risk (Kliejunas 2011). The consequences of increased white pine blister rust (Cronartium ribicola J.C. Fisch.) would 

be high (it has caused more damage and cost more to control than any other conifer 

disease), although its risk potential with climate change is low because it is associated with a cool, moist climate. Therefore, warmer temperatures would not favor 

blister rust, although more winter and spring precipitation could favor the pathogen 

(Kliejunas 2011). 
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Invasive Species 

Several hundred nonnative species grow in the North Cascades, but many are not 

currently invasive. Nonnative species, like native species, will respond individually 

to changes in climate based on species-specific physiological tolerances. However, 

many invasive species have common life history traits that distinguish them from 

native species and may cause them to be favored by a warmer climate and more 

disturbance of native vegetation. Many invasive species have broad climatic tolerances, large geographic ranges, and life history traits that facilitate rapid dispersal 

and growth (e.g., long-distance dispersal, low seed mass, short juvenile periods, and 

responsiveness to resource availability). Climate change may affect populations of 

invasive species by altering mechanisms for transport and introduction, reducing 

climatic constraints on existing populations, and increasing the impact on ecosystems by changing competitive interactions with native species (Hellmann et al. 

2008). Climate change may link geographic regions that were previously separated 

by eliminating climatic barriers, thus facilitating the spread of invasive species 

(Hellmann et al. 2008). Changes in climate could also reduce the range of some 

currently invasive species, although this is less likely because most invasive species 

grow over a wide range of environmental conditions, suggesting they will be able 

to tolerate changes in climate better than native species. Experiments with single 

species suggest that some invasive species may increase productivity in response 

to higher atmospheric CO2 and nitrogen deposition, but results are less clear for 

responses of invasive species growing in diverse plant communities in the natural 

environment (Dukes and Mooney 1999). More fire and insect outbreaks are likely 

to increase opportunities for invasive species to establish, because invasive species 

are typically better adapted than native species to take advantage of rapid availability of resources.

Cheatgrass (Bromus tectorum L.) is an exotic, invasive species of particular 

concern for North Cascades National Park (NOCA) and OWNF on the east side 

of the Cascades. Cheatgrass is an annual grass that is stimulated by fire and can 

prevent native grasses from successfully reestablishing after fire. Cheatgrass can 

permanently alter fire regimes if it persists because of its high flammability relative 

to native grasses (Brooks et al. 2004, Keeley 2006). Analysis of the climatically 

suitable habitat of cheatgrass throughout the Western United States indicates that 

climate change may cause a northward shift in its range, making north-central 

Washington more climatically suitable for cheatgrass (Bradley 2009). Elevated levels of atmospheric CO2 increase cheatgrass productivity and biomass (Ziska et al. 

2005). Furthermore, more frequent fire could favor existing populations of cheatgrass, creating a positive feedback that further alters fire regimes and decreases the 

potential for native understory species to regenerate. 

Invasive species may 

be favored by a warmer 

climate and more 

disturbance of native 

vegetation.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Disturbance Interactions 

The effects of climate change on the interaction of multiple disturbances (insects, 

fire, pathogens, and invasive species), or at least their combined influence (fig. 

5.13), will affect the region in novel ways in the future. For example, Hicke et al. 

(2012) developed a conceptual model of how insect mortality may affect fire, and 

concluded that the effects are time and system dependent. Insect mortality may 

increase the potential for fire occurrence and severity shortly after an outbreak but 

decrease severity in the long term. Box 5.1 describes another example of climate 

and disturbance interactions in whitebark pine populations in the North Cascades.

Figure 5.13—Fire perimeters (1984–2008) and aerial detection survey (ADS) insect and disease 

detection (1997–2008) show the recent disturbance area in the North Cascade Range. The total area 

affected is a high proportion of the landscape in the eastern Cascades. Data: Monitoring Trends in 

Burn Severity (MTBS) database, http://www.mtbs.gov.
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McKenzie et al. (2004, 2009) developed conceptual scenarios of future change 

in forested ecosystems and described plausible ecological mechanisms for the 

interaction of climate effects on vegetation, insects, and fire regimes. Novel forest conditions can emerge from interactions that are rare in the historical record. 

The rate of change in vegetation and species diversity is likely to be controlled by 

climate-driven changes in disturbances and the climate present during postdisturbance vegetation response, both of which are critical for understanding future 

vegetation trajectories (Littell et al. 2010, McKenzie et al. 2009). 

Vegetation Management Objectives

Management objectives for vegetation in the national forests and parks in the NCAP 

differ based on agency policies, mandates, and management legacies. However, 

management by zone designation (e.g., reserves vs. nonreserves) and fire regimes 

are similar across agencies in many ways. National Park Service (NPS) and USDA 

FS objectives for managing vegetation in the Pacific Northwest became more similar with implementation of the Northwest Forest Plan (NWFP) (USDA and USDI 

Box 5.1─Climate and Disturbance Interactions: 

Whitebark Pine in the North Cascades

The current status of whitebark pine in the Pacific Northwest (PNW) illustrates the 

effects of interacting disturbances and climate change on an ecologically valuable 

species. Whitebark pine grows at high elevations in the North Cascades and is typically found in small isolated populations on peaks and ridges. It is considered a keystone species because of its importance as a food source for several wildlife species. 

It also contributes to the character of high-elevation wilderness in the national forests 

and parks. 

Whitebark pine populations are declining because of mortality associated with white 

pine blister rust, mountain pine beetle, and perhaps lower fire frequency in the past 

century (Ward et al. 2006). Whitebark pine forests are projected to become more 

climatically suitable for mountain pine beetle (Hicke et al. 2006, Littell et al. 2010, 

Logan and Powell 2001, Logan et al. 2010). White pine blister rust has low risk potential with climate change, although more precipitation in spring and winter could favor 

the rust. Fire regimes and fire effects differ within the range of whitebark pine in the 

PNW. Fire can increase regeneration in wetter, more productive sites where competition with late-seral species is high, but fire can decrease populations in drier sites 

where regeneration after fire is slow (Ward et al. 2006). Thus, more area burned will 

likely affect populations differently depending on local fire regimes. The response of 

whitebark pine to direct effects of climate and indirect effects of climate on disturbances will differ within its range. Loss of whitebark pine, which is an earlysuccessional species, may reduce resilience of these areas to climate change because 

it facilitates establishment of other species (Resler and Tomback 2008).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

1994), which shifted vegetation management on national forests from an emphasis 

on sustained yield and multiple use to an emphasis on ecosystem management. 

Management objectives also became more similar with an increase in the area of 

Congressionally designated wilderness and wild and scenic rivers in the national 

forests. Restrictions on management in reserves in national forests and undeveloped 

areas in national parks limit options for managing vegetation to increase resilience 

to climate change, but these large areas of wilderness have been relatively less 

affected by past management and may have greater ecological capacity to adapt to 

climate change if ecological processes such as fire are maintained.

Mount Baker-Snoqualmie and Okanogan-Wenatchee

National Forests

General objectives for managing vegetation on the national forests are outlined 

in regional policies and land and resource management plans (i.e., forest plans) of 

each forest, which have a 15- to 20-year planning timeframe. However, the NWFP 

amended the forest plans of national forests within the range of the northern spotted owl (Strix occidentalis caurina Merriam). The NWFP significantly changed 

forest management objectives from a focus on sustained yield and multiple uses to 

a focus on ecosystem management and wildlife habitat. The primary objective of 

the NWFP is to provide for long-term sustainability of ecosystems and species that 

inhabit them. Vegetation management under the NWFP focuses on maintaining and 

protecting late-successional forests habitat for the northern spotted owl and marbled 

murrelet (Brachyramphus marmoratus Gmelin). The NWFP established a system of 

reserves that included Congressionally designated reserves (national parks, national 

monuments, wildernesses, and wild and scenic rivers), late-successional reserves 

(LSRs), riparian reserves, and administratively withdrawn areas (areas previously 

reserved from timber harvest by existing plans). Nonreserve areas include managed 

late-successional areas less than 80 years old, adaptive management areas (AMAs), 

and matrix (land not otherwise designated). In reserves, commercial timber harvest is prohibited and only limited silvicultural activities are permitted, so most 

silvicultural treatments occur in nonreserves. Despite the emphasis of the NWFP 

on long-term sustainability, the plan did not consider the possible effects of climate 

change on objectives or the designation of a static system of reserves. 

The NWFP applies to the entire Mount Baker-Snoqualmie National Forest 

(MBSNF), so objectives for forest management on the MBSNF are based on the 

goals and guidelines of the NWFP. The NWFP shifted the focus of vegetation 

management on MBSNF from commercial timber harvest to protection of latesuccessional forest habitat, restoration of previously harvested stands, and surveys 

The Northwest 

Forest Plan changed 

management focus 

from sustained 

yield and multiple 

uses to ecosystem 

management and 

wildlife habitat.
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of key species. Silvicultural treatments are limited to primarily nonreserve areas, 

which are only 5 percent of the forest area. In addition to silvicultural treatments 

and forest restoration, vegetation management includes programs for managing and 

monitoring rare plants, invasive species, fire, and hazard trees.

The primary objective of vegetation management in the OWNF is to restore fire 

regimes and wildlife habitat by managing ecological processes, stand structure, and 

species composition of fire-adapted forests that have been altered by past timber 

harvest and fire exclusion. The NWFP applies to most of the OWNF, except the 

area east and north of the Chewuch River. The area east and north of the Chewuch 

River is managed under the East-Side Screens Regional Management Plan (USDA 

FS 1998). Okanogan-Wenatchee National Forest is currently revising its forest plan, 

with the final decision planned for spring 2015. The revised forest plan will provide 

guidance for vegetation management that is consistent with the NWFP but specific 

to management needs of fire-adapted forests. General guidance for vegetation management on the OWNF is also provided by the Forest Restoration Strategy (USDA 

FS 2012a). In addition to forest restoration and silviculture, the OWNF manages 

fire, rare species, invasive species, and hazard trees.

Originally the NWFP included provisions for more active management of LSRs 

in fire-adapted forests east of the Cascade crest, and it was subsequently revised 

(USFWS 2008) to reflect an even greater need to manage these fire-adapted forests 

affected by fire exclusion (Spies et al. 2006). Revisions to the NWFP recognized 

that the original plan did not adequately reflect the current and potentially increasing threat to LSRs of severe wildfires and insect and pathogen outbreaks in the 

absence of fire and fuels management. Relative to the MBSNF, a greater proportion 

of the OWNF (60 percent) is not designated as wilderness or reserves under the 

NWFP, thus active management is more prevalent on the OWNF. The objectives 

of the East-Side Screens Regional Management Plan are also to protect and restore 

late-successional wildlife habitat, but by managing for natural range of variation, 

rather than a system of reserves, and limiting the size of trees that can be harvested. 

North Cascades and Mount Rainier National Parks

National Park Service management policies (USDI NPS 2006) focus on the use of 

natural processes to maintain native plant species, but managers may intervene to 

(1) manage populations that have been threatened by human influences; (2) accommodate intensive development in areas designated for developed uses; (3) protect 

rare, threatened, or endangered species; or (4) protect human safety and property. 

Given the emphasis on “natural process” and “native” species, one of the biggest 

challenges to vegetation management in the national parks will be to define what 
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processes are natural and which species are native as species ranges shift and 

disturbance rates increase with climate change. Attribution of climate change to 

human causes may be necessary to justify some interventions under current NPS 

policies. The NPS recognizes that natural processes and species are dynamic, and 

successful protection of these processes often requires protection of larger areas 

than are contained within park boundaries. Toward this end, the NPS collaborates 

with other agencies to conserve populations and habitats of native species outside 

of park boundaries and to monitor and collect data for use in plant management 

programs. Thus interagency collaboration in a regional approach to climate change 

adaptation is consistent with current NPS policies.

The primary objective of vegetation management in NOCA is to protect the 

ecological and genetic integrity of plant communities by protecting natural processes. The park was established to preserve mountain scenery including several 

aspects of vegetation: (1) diverse and extensive tracts of habitat, (2) dynamic 

ecosystem processes, (3) wetlands, and (4) diverse plant communities with rare 

species. Mount Rainier National Park was established to “...provide for the preservation from injury or spoliation of all timber, mineral deposits, natural curiosities, 

or wonders within said park, and their retention in their natural condition.” Similar 

to NOCA, the General Management Plan for Mount Rainier National Park (MORA) 

directs managers to protect and maintain plant communities and ecological processes and to restore plant communities when damaged (USDI NPS 2011a). Subalpine and alpine meadows are given special protection and are a focus of vegetation 

management because these systems are critical to the history and character of the 

park. Subalpine and alpine meadows are iconic ecosystems valued for wildlife 

habitat, viewing wildflowers, and the general recreation experience of visitors.

Vegetation Management Practices 

Silviculture and Forest Restoration 

Most silvicultural treatments on the MBSNF are designed to restore and develop 

late-successional forest habitat. Commercial harvest and noncommercial thinning are used to restore late-successional habitat, with the secondary objectives of 

producing timber and increasing tree vigor. However, the annual area treated on 

the MBSNF is currently small. Commercial timber harvest in the MBSNF occurs 

in several hundred hectares per year and noncommercial thinning in less than 300 

ha per year in LSRs less than 80 years old, matrix lands, and AMAs. Common 

silvicultural prescriptions include variable-density thinning, retention of minor tree 

species to maintain diversity, and inclusion of some unharvested patches and large 

openings to promote horizontally diverse stand structure. Current treatments do 
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not reflect expected climate-driven changes in species distributions, tree vigor, or 

disturbance rates. 

Current objectives of silvicultural treatments and restoration on the OWNF are 

to restore natural forest processes, patterns, and function in order to increase forest 

resilience to changes in climate and disturbance regimes. The area is managed for 

historical and future range of variability in species composition and stand structure (Gärtner et al. 2008). Specific management goals are to reduce stand density, 

shade-tolerant fir species, and elevated fuel loads that now cover a greater portion 

of the forest because of past timber harvesting and fire exclusion. These changes in 

forest structure and composition have led to an increase in severe wildfire, defoliating insects, dwarf mistletoe, bark beetles, and root diseases (Hessburg et al. 2000). 

Managers on the OWNF use a landscape planning tool (Ecosystem Management 

Decision Support framework; Reynolds and Hessburg 2005) to determine priority 

areas for restoration treatments that will increase forest resilience. After selecting 

priority areas, specific silvicultural prescriptions are determined and projects are 

implemented based on site-specific conditions. Forest restoration activities on the 

OWNF include commercial thinning, noncommercial thinning, and prescribed fire. 

Approximately 120 000 m3 yr

-1 are harvested, but timber harvest is limited by the 

lack of mills in the region and the high cost of transporting logs to distant mills. 

Fire and Hazardous Fuel Management

Historically, maritime coniferous forests and subalpine forests that dominate the 

MBSNF burned infrequently, limiting the need for fuel treatments and prescribed 

fire. Given the emphasis on historical fire regimes and the objectives of safety 

and protecting resources, fire management currently focuses on fire suppression. 

Forests in MORA have a similar historical fire regime, but the park developed a 

fire management plan in 2005 (revised in 2011) (USDI NPS 2005) with the goals 

of ensuring firefighter and public safety, protecting natural and cultural resources, 

and restoring and maintaining natural fire regimes. Suppression is a priority near 

park administrative facilities, access roads, and developed zones. Elsewhere in 

the park, managers have the option of managing wildfires to encourage fire as a 

natural process. The plan recognizes that fire severity and extent may change as 

climate warms and that park management will need to adapt to these changes in 

fire regimes. The plan also recognizes that fire is a large-scale process and needs to 

be managed in collaboration with adjacent landowners.

The OWNF and NOCA actively manage fire and fuels in forests with low- and 

mixed-severity fire regimes east of the Cascade crest. The OWNF Forest Restoration Strategy and revised forest plan recognize fire as an essential process for 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

maintaining resilient forest and nonforest ecosystems, and support active use of 

fire. However, protection of human life is the highest priority of fire management, 

and fire managers set priorities for protecting communities, property, and natural 

and cultural resources based on the values to be protected, risks to human health 

and safety, and costs of protection. Fire management activities include using 

planned and unplanned ignitions for multiple resource objectives. However, air 

quality associated with smoke emissions often limits the area that can be burned for 

ecological objectives. Managers use natural and artificial regeneration (i.e., planting seedlings) after harvests and fire, but planting has declined recently because it 

results in higher tree densities that require subsequent thinning.

The objectives of the NOCA fire management plan (USDI NPS 2007) are 

to ensure the safety of firefighters and the general public, allow for natural fire 

processes, use adaptive management to guide future fire management, and educate, 

inform, consult, and collaborate with stakeholders and adjacent land managers. Fire 

management activities include suppression, prescribed fire, and mechanical treatment of hazardous fuels. Fires are suppressed to protect human life and property 

and to prevent fires from burning into Canada or causing undesirable effects to 

threatened and endangered species and their habitats. Prescribed fire and wildfires 

are managed in both wilderness and developed zones. When conditions allow, 

lightning-caused fires can be managed to meet multiple objectives in wilderness. 

North Cascades National Park Complex monitors fire effects of prescribed burns 

and wildfires. These data are used in an adaptive management process to determine 

if wildfires and prescribed burns are achieving desired objectives and ecological 

conditions.

Hazard Tree Management

Although hazard tree management occurs at small scales in local areas, it is an 

important component of vegetation management because hazard trees present a risk 

to human life and property. A hazard tree has a detectable defect that could cause 

it to fall and strike a person or property in a developed area (e.g., campground, 

building, or parking area). Managers monitor hazard trees when they pose a threat 

to people or property, and mitigate potential damage through site closure, pruning, 

reducing tree height, or complete removal of the tree. 

Plant Ecology Programs

Plant ecology programs in MORA and NOCA include nonnative plant management, 

long-term monitoring, rare plant protection, environmental compliance surveys, and 

restoration. The condition of plant communities is monitored, and managers mitigate damage and restore natural vegetation when it is determined that human use 
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has degraded an area. Restoration programs focus on areas damaged by recreational 

use, road construction, or other administrative actions. The majority of restoration 

projects in MORA are in subalpine forest, and projects in NOCA are concentrated 

in lower elevation areas associated with exotic plants or erosion control. Restoration in MORA has occurred mostly in subalpine meadows that have been damaged 

by recreational activity, and in areas where construction has damaged vegetation. 

Restoration in NOCA has occurred mostly in subalpine areas near Cascade Pass, as 

well as areas near Ross Lake, Diablo Lake, and Lake Chelan. 

Both parks maintain greenhouses and propagate the majority of plants used 

in restoration programs. Seed or propagule collection is conducted adjacent to 

restoration sites to protect genetic integrity of the plant communities. Roadside 

revegetation projects often use seed programs conducted by the Natural Resources 

Conservation Service or private contractors and use a larger seed collection area. 

Both parks collaborate with the USDA FS to screen whitebark pine for genetic 

resistance to white pine blister rust.

Federal law requires national forests and parks to protect threatened and endangered plant species listed by the USFWS under the federal Endangered Species Act 

(ESA) of 1973. The national parks also protect plants on the state of Washington, 

Natural Heritage Program list of rare plants (WADNR 2012b). The national forests 

also monitor and manage species on the USDA FS Pacific Northwest Region 

sensitive species list, which includes federally listed species. Regardless of how 

these sensitive species will be affected by changes in climate and disturbances, the 

agencies are legally required to protect and maintain current populations of listed 

species. Thus adaptation planning must consider this current management context. 

The MBSNF has 34 species on the PNW sensitive list and also manages 54 

species of lichens, bryophytes, fungi, and vascular plants known as “survey and 

manage” species under the Survey and Manage Settlement Agreement (2011). 

The OWNF manages 91 plant species on the PNW sensitive species list that grow 

in a wide range of environments from alpine tundra to low-elevation forests, and 

has two suspected and two known federally listed plant species, two of which are 

local endemics. There is only one federal candidate species in NOCA, but the park 

has 24 vascular plants that are listed by the state of Washington, Natural Heritage 

Program. There is one species of federal concern, three state sensitive species, four 

state watch species, and one priority macrofungus species in MORA.

Invasive Species Management

National forests and parks in the NCAP already coordinate management of invasive 

species and collaborate with other agencies in the region. Exotic species are those 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

that occupy or could occupy lands directly or indirectly as a result of deliberate 

or accidental human activities. Invasive species are more specifically defined as 

nonnative species that are aggressive and pose an ecological threat to the integrity 

of native vegetation (USDI NPS 2006). Both agencies use an “early detection-rapid 

response” approach to identify potentially problematic invasive species as early as 

possible, develop a strategy for treatment, and implement timely treatment where 

eradication or control are feasible.

Direction for management of invasive species on the national forests is given by 

the Pacific Northwest Region, Invasive Plant Program, Preventing and Managing 

Invasive Plants Record of Decision (USDA FS 2005), which standardizes invasive 

plant management. Guided by the region’s environmental impact statement (EIS) 

for invasive plants, the individual national forests operate under a site-specific EIS 

or environmental assessment (EA). The forest-level EIS for the OWNF treat 2000 

to 4000 ha per year in priority watersheds. The MBSNF is currently operating 

under an EA, which targets management for 51 nonnative invasive plants, and is 

developing an EIS to expand treatment procedures and manage invasive species in 

wilderness areas.

The 2005 USDA FS regional invasive plant program expands invasive plant 

prevention with more options for treatment and control, and increases emphasis 

on early detection, monitoring, and restoration of native plant communities. The 

MBSNF and OWNF both emphasize education for recognizing, reporting, and 

preventing the spread of invasive species, especially in high-priority areas such as 

portals to wilderness. The national forests also replant sites previously treated for 

invasive species with native species to prevent reinvasion. Seed, mulch, and gravel/

fill materials are required to be “weed free.” 

The MORA contains an estimated 152 nonnative invasive species, approximately 15 percent of the park flora. The NOCA contains 225 known nonnative 

species, 40 of which are currently deemed invasive and targeted for control (USDI 

NPS 2011b). The park recently completed an EA for management of invasive nonnative plants (USDI NPS 2011b). Both parks utilize an integrated pest management 

program to eradicate or control invasive species, restore invaded areas, and detect 

and prevent new invasions. Control methods for invasive species include manual, 

mechanical, biological, or chemical treatments. Chemical treatments are generally 

used in limited locations and for species for which this is the only effective control 

method. Invasive species management also includes inventory and monitoring, 

restoration of native plant communities, and outreach, education, and collaboration. 

Federal agencies use 

an “early detectionrapid response”

approach to identify 

problematic invasive 

species, develop a 

treatment strategy, 

and implement timely 

treatment.
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Changes in population dynamics of invasive species will challenge these current management practices for invasive species. Climate change could challenge the 

definition of invasive species because some currently invasive species may diminish, some nonnative species that are not currently invasive may become invasive, 

and native species may experience range shifts and grow in places where they have 

not historically. Current methods of chemical, biological, and mechanical control of 

invasive species may become less effective in a changing climate (Hellmann et al. 

2008).

Inventory and Monitoring

National forests and parks in the NCAP inventory and monitor vegetation, disturbances, and priority ecological indicators. The USDA FS Forest Inventory and 

Analysis (FIA) program monitors status and trends in forests on both USDA FS 

and NPS lands (USDA FS 2012b). The FIA program periodically inventories forest 

vegetation, fuels, and soils. The USDA FS Pacific Northwest Regional Ecology 

Program also inventories plant communities and monitors tree growth. The USDA 

FS Health and Monitoring Program is an interagency program that detects and 

evaluates forest insects and pathogens on all lands through aerial and ground-based 

surveys (USDA FS 2012c). In Washington, this program conducts annual aerial 

surveys of forest insects and pathogens in coordination with WADNR. These 

monitoring programs are not specifically designed to detect trends associated 

with climate change, but the data collected can be used to assess recent effects of 

changes in climate. 

Long-term monitoring of forest, subalpine, and alpine ecosystems in MORA 

and NOCA is implemented in partnership with the North Coast and Cascades 

Network Inventory and Monitoring Program. Forest monitoring focuses on Douglas-fir/western hemlock forests (600 to 900 m) and cool, dry subalpine forests (1500 

to 1800 m). Monitoring includes annual assessment of tree mortality and 5-year 

reviews of growth and recruitment (Acker et al. 2010). Monitoring of alpine and 

subalpine ecosystems includes health of whitebark pine stands, trends in composition and structure of subalpine and alpine vegetation, soil temperatures, and snow 

cover (Rochefort et al. 2012). 

Adapting Vegetation Management in a Changing 

Climate 

During the NCAP workshop, scientists and managers reviewed the vulnerability of 

vegetation to changes in climate and disturbances and current vegetation management practices. Based on this information, workshop participants identified options 
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Box 5.2─Themes for Adapting Vegetation Management

in the North Cascades

Four themes for adapting vegetation management to climate change emerged from the 

North Cascadia Adaptation Partnership (NCAP) workshop on vegetation and ecological 

disturbances.

1. Ecosystem management is highly compatible with climate change adaptation.

Ecosystem management (Chistensen 1996, USDA and USDI 1994) as the guiding paradigm for management on the Mount Baker-Snoqualmie and Okanogen-Wenatchee 

National Forests is compatible with adapting vegetation management to climate change. 

Ecosystem management requires managing for long-term ecological sustainability 

(guided by historical variability and tempered by climate change) and is based on a sound 

understanding of ecology, use of ecological models, and recognition that ecosystems are 

dynamic, all critical components of adaptation planning. Several adaptation options identified in the workshop are consistent with current ecosystem management practices, such 

as accelerating development of late-successional forests and restoring ecological processes 

associated with disturbance regimes. However, climate change creates a new context with 

which to evaluate specific objectives of ecosystem management. 

2. Management objectives of the National Park Service for protecting biologically 

diverse and functioning ecosystems and processes by mitigating adverse effects of 

humans are highly compatible with climate change adaptation. Several adaptation 

options identified in the NCAP workshop focused on reducing existing human-induced 

threats to vulnerable species and ecosystems. Reducing current human-induced threats 

can improve the potential for species and ecosystems to naturally adapt to changes in 

climate. However, as climate continues to change, additional actions will be necessary to 

maintain resilience of ecosystem function and process.

3. Adaptation options focused on “no regrets” strategies. “No regrets” strategies are 

robust to uncertainty in future climate, and often include current management practices 

aimed at restoring ecosystem processes. These strategies require placing greater importance on current management actions that facilitate resilient ecosystems regardless of the 

exact effects of climate change. Many adaptation strategies identified in the workshop 

included management practices that are already in place, but participants identified ways 

that climate change may increase urgency, shift priorities, or require additional resources 

and collaboration to ensure that current objectives can still be achieved in a changing 

climate. Given inherent uncertainties in climate change and effects on vegetation, “no 

regrets” strategies are a conservative way to move forward.

4. Adaptation strategies differed more by management zone and fire regime than by

agency. Some adaptation strategies differed based on differences in the agency mandates 

of U.S. Department of Agriculture Forest Service and National Park Service, but adaptation strategies differed more based on actions that could be implemented in developed and 

intensively managed areas vs. reserves and wilderness. Adaptation for managing fire also 

differed more based on historical fire regimes and past fire management than by agency, 

with different options identified for fire-adapted forests than for forests with historically 

infrequent fire. Although, some adaptation options were more applicable to reserves (i.e., 

late-successional reserves and wilderness) and others to nonreserves (i.e., damaged areas 

and developed zones in parks; matrix, adaptive management areas, and national forest 

lands outside of the Northwest Forest Plan area), the coordination between the agencies 

shows promise for implementing an “all lands approach” to climate change adaptation.
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general technical report pnw-gtr-892 Table 5.2—Sensitivities of vegetation to changes in disturbance regimes; adaptation strategies and tactics to reduce impacts Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needs Sensitivity: Reduced tree vigor and increased tree susceptibility to insects and pathogens. Strategy: Increase resilience of forest stands to disturbances by increasing tree vigor. • Thin to accelerate development of late-suc- cessional forest conditions • Harvest to variable densities • Thin to decrease stand density and increase tree vigor • Reduce density of post-disturbance artificial regeneration on the (Okanogan-Wenatchee National Forest [OWNF])

• Consider using genetically improved seedling stock

• Plant resistant species or genotypes where

species-specific insects or pathogens are aconcern

• Increase stand-level biodiversity and minimize monocultures

• Treat existing pathogen outbreaks with more

aggressive management

Short term, long term, opportunistic

Post disturbance managementPlanning process of the National Environmental Policy Act can be an opportunity for incorporating climate change adaptation into projectsCurrent ecosystem management paradigm of U.S. Department of Agriculture Forest Service (USDA FS) managementLearn from the experience of other public and private land management organizationsIncrease public education of the need for adaptation managementOWNF Forest Restoration Strategy

Limited resources to treat the large amount of area currently in need of treatmentPublic opposition to active management in some cases

Information to guide selection of alternative species and genotypes for plantingExperimental genetic outplantingIdentify drought resistant species and genotypesGreater ecological understanding of the effects of assisted migrationSilvicultural prescriptions or research to inform thinning levels

Sensitivity: Increased potential for large and extensive insect and pathogen outbreaks.

Strategy: Increase forest landscape resilience to large and extensive insect or pathogen out breaks (nonreserve lands).

• Design forest gaps that create establishment

opportunities

• Increase diversity of patch sizes• Consider planting desired species (assisted 

migration) rather than relying on natural regeneration and migration

Short term, long term, opportunistic

Adaptive management areas and matrix landsCollaboration with private timber companies

Public opposition to active management in some casesActive management is prohibited in wilderness and limited in late-successional reservesLimited ability to treat large enough area
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Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needsSensitivity: More fire (larger aerial extent and more high-severity patches) and more area in recently burned or early-successional stages.

Strategy: Plan and prepare for more frequent and severe fire and greater area burned.

• Incorporate climate change into fire management plans

• Anticipate more opportunities to use wildfire 

for resource benefit

• Plan postfire response for large fires (Mount 

Baker-Snoqualmie National Forest) 

• Consider using prescribed fire to facilitate 

transition to a new fire regime in drier forests (Mount Rainier National Park [MORA]) 

• Consider planting fire-tolerant tree species post-fire in areas with increasing fire 

frequency.

• Manage forest restoration for future range of 

variability (OWNF)

Short term Provisions in North Cascades 

National Park (NOCA) fire management plan for greater use of wildfire and potential to reignite lighting-ignited fires that have been suppressed as prescribed firesCurrent fire management direction increases flexibility (NOCA, OWNF)OWNF Forest Restoration StrategyUnit-specific fire management plans

Risk of and institutional resistance to using natural ignitionsAdditional resources required to manage reignited wildfires as prescribed fires

Strategy: Increase resilience of existing 

vegetation by reducing hazardous fuels.

• Thin and prescribe burn to reduce hazardous

fuels in the wildland-urban interface (nonreserve)

• Increase intentional use, management, and 

reignition of lightning-ignited fires (NOCA)

• Consider using more prescribed fire where 

scientific evidence supports change to more frequent fire regime (MORA)

• Consider thinning outside of wildland-urban 

interface if fire risk necessitates

• Increase interagency coordination and 

shared risk

Short term Current efforts to assess fuels 

on USDA FS and National Park Service (NPS) lands will facilitate treatment prioritization 

Air quality standards and restrictions limit prescribed burningUncertainty in the ecological effects of reignited and prescribed fires

Adaptive management to assess fire effects and changes in fire regimes, particularly in ecosystems that are currently not fire-prone

Table 5.2—Sensitivities of vegetation to changes in disturbance regimes; adaptation strategies and tactics to reduce impacts (continued)
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general technical report pnw-gtr-892 Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needs Strategy: Increase resilience through postfire management (nonreserve).

• Consider climate change in postfire

rehabilitation

• Determine where native seed may be needed 

for postfire planting

• Anticipate greater need for seed sources and 

propagated plants

• Experiment with planting native grass species to compete with cheatgrass postfire

• Increase postfire monitoring in areas not 

currently monitored

Long term, opportunistic

Planting after disturbancesMonitoring after disturbancesAdaptive management areas and matrix landsNOCA fire monitoring program could be emulated in other less fire-prone ecosystems

Limitations on storing native seed increase difficulty of keeping native seed readily availableLimited personnel and resources after disturbances because of other hiring priorities and needs

Research to indicate seed vitality over timeInformation to determine priority areas to monitor postfireLack of funding for longterm monitoring

Table 5.2—Sensitivities of vegetation to changes in disturbance regimes; adaptation strategies and tactics to reduce impacts (continued)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

for adapting management to climate change with the goals of reducing vulnerability 

and increasing resilience. Workshop participants identified adaptation strategies 

associated with increasing resistance, resilience, and response (Millar et al. 2007). 

To move beyond these general concepts, participants also identified specific on-theground tactics and appropriate timeframes for implementation. Short-term tactics 

are those that are already being implemented or could be implemented based on 

current resources and scientific knowledge. Long-term tactics may be implemented 

as uncertainty in climate change effects is reduced or as more resources become 

available for adaptation. Participants also identified barriers, opportunities, and 

research needs for implementing adaptation strategies and tactics. Four general 

themes for adapting vegetation management to climate change emerged from the 

workshop and subsequent discussions with scientists and managers (box 5.2). 

Adaptation Options for Managing Ecological Disturbances 

Managers may consider adapting vegetation management practices to increase 

both stand and landscape resilience to disturbance as rates of insect, pathogen, and 

fire disturbances increase (Dale et al. 2001, Littell et al. 2012, Millar et al. 2007). 

Workshop participants identified several strategies and tactics for increasing stand 

and landscape resilience to disturbances (table 5.2), starting with existing practices 

that are already designed to increase resilience to disturbance. These practices will 

continue to be useful as climate changes, but modifications or new approaches may 

become increasingly necessary to increase resilience as climate-driven changes in 

disturbance regimes are realized (Millar et al. 2007). 

Current management in MBSNF to thin stands and accelerate development of 

late-successional habitat can also increase resilience to disturbance by reducing 

stand density and summer moisture stress, thus increasing tree vigor and reducing 

susceptibility to insects and pathogens. Current silvicultural prescriptions could be 

modified to increase resilience by further reducing tree density and creating gaps 

to favor establishment of drought-tolerant species (Halofsky et al. 2011, Littell et 

al. 2012). Currently, OWNF and MBSNF managers use artificial regeneration on 

only a small area each year, but planting practices could be adapted for changes in 

climate change. In dry fire-adapted forests, resilience to moisture stress could be 

increased by planting at lower densities, planting more drought-tolerant species and 

genotypes, or relying on natural regeneration when present. Natural regeneration 

may result in sufficient densities and prevent future need to burn or thin stands to 

reduce density. Where species-specific insects or pathogens are likely to increase, 

stand-scale resilience could be increased by planting resistant species, genotypes, or 

genetically improved stock to increase biodiversity and prevent the establishment of 

Thinning and 

accelerating 

development of latesuccessional habitat 

can increase resilience 

to disturbance.
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monocultures, which are more vulnerable to insect and pathogen outbreaks (Littell 

et al. 2012).

Greater heterogeneity in patch size, stand age, and stand size over large spatial 

scales can increase resilience by decreasing contagion of insect and pathogen outbreaks and inhibiting the spread of wildfires (Littell et al. 2012, Millar et al. 2007). 

For example, mountain pine beetle favors mature pine trees, and the homogeneity 

of the landscape with respect to tree species and age can contribute to extensive 

outbreaks. Forests in OWNF are more vulnerable to widespread insect outbreaks 

because past harvesting, fire suppression, and fire exclusion have decreased the 

area of open stands of large pine trees (Harrod et al. 1999). Management under the 

NWFP has also decreased the area of structurally diverse early-successional stands 

(Spies et al. 2006). Fire exclusion in forests with low- and mixed-severity fire 

regimes has increased the area of forests that have high densities of shade-tolerant 

species and vertical fuel continuity, which increase susceptibility to more severe 

fire and insect outbreaks. Reducing the homogeneity of the landscape created 

by past management can increase landscape resilience to future disturbance, but 

increasing resilience will require that more area be treated than is currently being 

treated. 

In the short term, most forest management to increase stand and landscape 

resilience will likely need to be implemented on nonreserve lands, because current 

policies associated with the NWFP and Wilderness Act (Wilderness Act of 1964) 

limit thinning in reserves and wilderness. Currently, thinning of forest stands 

in MBSNF is done only in the matrix, AMAs, and LSRs under 80 years old. In 

the long term, increasing resilience to climate change may require increasing 

silvicultural treatments in these areas, but also considering more flexible policies 

for managing reserves for resilience to disturbance. The OWNF actively manages 

more land than MBSNF as part of the OWNF Forest Restoration Strategy, which 

specifically identifies an approach to increasing resilience in fire-adapted forests by 

focusing on the future, rather than historical, range of variability in stand age and 

structural classes (Gärtner 2008). Thus the OWNF currently has more opportunities and flexibility to incorporate adaptation into forest restoration, but changes in 

policy would be required to actively manage additional areas for increased resilience to disturbance and climate change. 

Adaptation tactics for increasing stand and landscape resilience can be implemented at the project level, and the National Environmental Policy Act (NEPA) of 

1969 (NEPA 1969) planning process can be an opportunity to incorporate climate 

change adaptation into projects. This process could be facilitated with research to 
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identify species and genotypes that are resistant to insects, pathogens, and drought, 

as well as research on the ecological effects of assisted migration. This information 

can guide selection processes for artificial regeneration and support decisionmaking 

under NEPA. The private sector and local and state agencies (e.g., WADNR) that 

manage more land for timber production may have greater flexibility to experiment 

with alternative silvicultural prescriptions and planting practices. The NCAP provides an opportunity for agencies to collaborate and share knowledge as practices 

are modified and tested. Public education about the value of active forest management in a changing climate would engender public support for adaptation actions. 

In addition to increasing stand and landscape resilience, adapting vegetation 

management in the North Cascades may require addressing increased extent and 

severity of wildfire. Adaptation strategies for changing fire regimes differ by 

management zone and will likely need to evolve over time as fire regimes change 

(table 5.2). Considering climate change in fire management plans will help with 

the preparation of postfire responses. Accelerating hazardous fuel treatments with 

prescribed fire and mechanical treatments may be necessary to keep pace with 

increased area burned and longer fire seasons (Dale et al. 2001, Littell et al. 2012, 

Peterson et al. 2011b). Climate is an important control on area burned (Littell et 

al. 2009) and severe fire seasons are more likely as climate changes (Littell et al. 

2010). Thus the effectiveness of current fuel treatment prescriptions may decrease 

as climate changes and additional firefighting capability may be needed to suppress 

fires that threaten people, property, forest products, and other forest resources. 

Planning for postfire recovery may benefit from considering how climate after 

a fire differs from the climate under which a forest initiated and developed (Littell 

et al. 2012, Peterson et al. 2011b). More postfire monitoring will be necessary to 

detect and prevent the establishment of invasive species and to assess regeneration success. Access to native seed sources will be increasingly important, as will 

identifying priority locations for postfire planting to facilitate regeneration of native 

plants that will be resilient to future climate. Monitoring of postdisturbance planting can ensure drought tolerance and the successful competition of native plants 

with invasive species (Littell et al. 2012). Postfire rehabilitation and restoration 

projects are opportunities to affect future forest succession and facilitate adaptation. 

Increased wildfire may create more opportunities to manage wildfires burning 

in wilderness for ecological benefits. Managing fire as a natural process in designated wilderness is consistent with current policies (USDI NPS 2006). Large areas 

of continuous wilderness in the North Cascades are locations with the potential to 

restore the natural function of fire (Miller et al. 2011). The NOCA fire management 
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Box 5.3─Climate Change and Ecosystem Services in the 

North Cascades

Multiple services provided by ecosystems of the national forests and parks in the 

North Cascadia Adaptation Partnership (NCAP) will be affected by changes in vegetation distributions and ecological disturbances. During the NCAP workshop on climate change, vegetation and ecological disturbances, participants identified several of 

these ecosystem services. Ecosystem services are defined as the benefits that people 

receive from natural systems (Smith et al. 2011) and they consist of supporting services, regulating services, provisioning services, and cultural services (MEA 2005). 

Supporting services are the functions of natural systems such as nutrient cycling. 

Regulatory services provide benefits to humans associated with ecosystem processes 

such as air quality, climate, and water regulation. Provisioning services provide direct 

products to humans in the form of water, food, and fiber. Cultural services are the experiences humans derive from ecosystems including recreation and aesthetic values. 

Provisioning of fresh water (quality and quantity), cultural (recreational and aesthetic) 

and biodiversity are three dominant ecosystem services that are vulnerable to climate 

change in the NCAP region.

Ecosystem services are one way that national forests and parks can expand communication of the benefits and values the public receives from these lands, and how those 

benefits and values may be affected by climate change. Management goals will need 

to be modified and reevaluated as climate changes. As social and ecological systems 

adapt to climate change, changes in these services will affect social perception and 

support for climate change adaptation (Vose et al. 2012). 

Supporting and regulatory services will likely be altered by changes in ecological 

disturbances and to a lesser degree by changes in vegetation distribution. Increased 

fire and associated increases in fuel consumption, smoke emissions, and erosion could 

affect air and water quality. The extensive and highly productive forests in the North 

Cascades regulate climate and store carbon, and forests in the western Cascades have 

high annual rates of carbon uptake and contain some of the highest carbon stocks 

of any temperate forest region in the world (Smithwick et al. 2002). Increased fire, 

insect, and pathogen disturbances are likely to reduce carbon stores (Kurz et al. 2008, 

Raymond and McKenzie 2012). Carbon release through disturbance followed by carbon uptake through vegetation regrowth is a process that balances over long time periods and large spatial scales, creating a carbon-neutral landscape (Ryan et al. 2010). 

However, altered extent and frequency of disturbances can shift the landscape to act 

as a carbon sink or source (Raymond and McKenzie 2012). Increased fire and insect 

disturbances will likely shift the North Cascades towards a carbon source, although 

the magnitude of this source could be offset partially by forest regrowth following 

timber harvesting of the 20th century and higher productivity in high-elevation forests. An uncertainty in carbon regulation is the contribution of delays in regeneration 

(Kashian et al. 2006) or conversions to other vegetation types (e.g., Savage and Mast 

2005), both of which could further reduce carbon stores. If vegetation regenerates to 

predisturbance densities, there is no net loss of carbon, but if vegetation is slow to regenerate because of unfavorable climate or competition with invasive species, carbon 

stores will decline. (continued on next page.)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Box 5.3─Climate Change and Ecosystem Services in the 

North Cascades (continued)

The importance of timber as a provisioning service in north-central Washington 

has declined in recent decades, but some timber and biomass are harvested on 

Okanogan-Wenatchee National Forest (OWNF) and, to a lesser degree, on Mount 

Baker-Snoqualmie National Forest (MBSNF). Douglas-fir and ponderosa pine forests 

managed for timber on OWNF will likely experience decreased tree growth and 

productivity because of moisture limitations with warmer summer temperatures and 

no increase in summer precipitation. However, a greater effect will likely be the loss 

of forest cover to disturbance. In the low-elevation Douglas-fir forests that are managed for timber on MBSNF, changes in forest productivity will likely be minimal 

and depend on seasonal changes in precipitation and the timing of spring snowmelt. 

Projections of minimal change or small decreases in summer water balance deficit in 

these forests suggest that forest productivity will not change substantially except in 

the driest areas. 

Cultural services provided by the national forests and national parks in the NCAP 

are critical to the character of the parks and forests, as well as local and regional 

economies. These public lands provide scenic vistas, aesthetic values, and spiritual 

and recreational opportunities. The parks and wilderness in the national forests are 

designated as class 1 areas under the 1977 Clean Air Act. More area burned and 

more severe fire will challenge management to prevent deterioration of visibility and 

scenic views, an important component of the recreation experience. National forests 

and parks in the NCAP have high visitation because of their proximity to the EverettSeattle-Tacoma metropolitan area. More ecological disturbances will reduce access 

and change the timing of some recreational activities. More tree mortality from insects, pathogens, and fire will increase hazard trees in developed areas, creating risks 

to people and property. More extensive insect outbreaks and fires will create large 

areas of dead trees and early-successional forests, which could affect the aesthetics 

and character of the landscape and the experience of visitors. Changes in disturbance 

regimes may also directly affect access. More fires and associated smoke emissions 

may cause more road, trail, and facility closures. Warmer, drier conditions, even in 

the absence of fires, could increase fire precaution levels and thus restrict activities of 

managers and visitors of the national parks and forests. 

Adapting vegetation management for climate change will complement management of 

some ecosystem services but introduce tradeoffs for others. Many adaptation strategies for increasing vegetation resilience that were identified in the NCAP workshop 

involve protecting and maintaining ecosystem processes, which will enhance regulating and supporting services including biological diversity and water quality. Other 

adaptation strategies will create tradeoffs with some ecosystem services. Efforts to 

protect rare and sensitive species and restore native plant communities may require 

reducing access and visitation. Managing fire as a natural process with prescribed fire 

and managed natural ignitions could negatively affect air quality, carbon storage, scenic views, recreation, and aesthetic values. Mechanical removal of hazardous fuels to 

increase forest resilience and resistance to fire and insects will decrease carbon stocks 

and release carbon dioxide to the atmosphere in the short term, but they may reduce 

carbon emissions and improve air quality in the long term by preventing more severe 

or extensive disturbances. These treatments also protect timber supplies, enhance productivity, and can provide a potentially valuable source of fiber.
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plan, which allows previously suppressed lightning-ignited fires to be ignited again, 

provides an opportunity to implement this strategy. The OWNF fire management 

does not have a similar provision, but wildfires burning in wilderness do not need 

to be suppressed if they do not threaten lives and property and if fire suppression 

efforts would present unnecessary risks to firefighters. Managing fire in this way 

may facilitate the transition to the more frequent fire regimes expected with climate 

change (Peterson et al. 2011b). Allowing for a gradual transition by managing 

wildfires now may prevent more severe wildfires, abrupt transitions, or ecological thresholds from being crossed that could lead to the conversion of forests to 

grasslands or shrublands and cause significant loss of ecosystem services. However, 

managing fire as a natural process will require accepting more short-term risks, 

consequences, and tradeoffs for managing air quality, carbon, access, invasive species, and habitat loss (Littell et al. 2012, Millar et al. 2007).

In the long term, additional adaptation strategies may be necessary to facilitate the response of forests and fire regimes to climate change and prevent the 

loss of ecosystem services (Millar et al. 2007) (box 5.3). Adaptation may require 

facilitating the transition to new fire regimes through planting fire-tolerant species 

and using prescribed fire in forest types that have experienced less frequent fire 

historically. The fire effects monitoring program at NOCA currently enables adaptive management by collecting data on fire effects, which can be used to identify 

changes in the ecological effects of fire as climate changes. This program could be 

used as a model to monitor additional areas that are not currently monitored for fire 

effects and to detect changes in the ecological function of fire over time. 

Adaptation Options for Managing Floods, Wind, and Hazard 

Trees

Projected changes in the intensity and frequency of windstorms are not yet available, but as atmospheric circulation patterns change (Salathé et al. 2010), the 

intensity and frequency of wind may increase, creating more windthrow. Woody 

debris from Douglas-fir provide hosts for Douglas-fir beetles. In nonreserve areas, 

managers could increase resilience to outbreaks of Douglas-fir beetle by removing wind-killed trees and increasing the use of Douglas-fir beetle antiaggregation 

pheromones to protect trees. These intensive measures may be most appropriate 

where hazard trees threaten people or infrastructure, or for socially and ecologically 

valuable trees. More monitoring could determine where management of Douglas-fir 

beetle will be most necessary and effective. Projections of changes in wind patterns or intensity will help identify areas that will be exposed to increased wind, 

windthrow, and associated insects. 

Allowing some fires to 

burn in wilderness may 

prevent more severe 

wildfires in the future.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 5.3—Sensitivities of vegetation to changes in flood and wind disturbances; adaptation strategies and tactics to reduce impacts

Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needsSensitivity: Increased wind activity and potential for increased blowdown and associated Douglas-fir beetle or spruce budworm. 

Strategy: Increase vegetation resilience to windstorms. 

• Monitor Douglas-fir beetle activity after 

wind storms 

• Remove Douglas-fir and spruce windthrow 

to limit insect infestation (nonreserve)

• Increase use of Douglas-fir beetle antiaggregation pheromones

Short term Blowdown events can be opportunities to manage succession and 

species and genetic diversity

Additional information on how wind will change with climate change

Sensitivity: Increased flooding and impacts to riparian vegetation and aquatic habitat.

Strategy: Plan and prepare for more frequent and severe flood events.

• Restore native plant species in riparian 

areas

• Control invasive plant species in floodprone reaches• Expand current restoration projects to mitigate increasing flood risk

• Avoid committing resources for restoration in areas with high flood risk; prioritize 

areas with low flood risk

• Use natural flood protection (e.g., vegetation or engineered logjams)

Short term, long term

Flood events can be opportunities for restoration that affect future vulnerabilityAdditional resource availability after floods can help accomplish objectives of restoring the natural flood plain

Evaluation of existing invasive species control in riparian areasIdentification of areas with increasing flood risk to prioritize for restorationAdditional planning to anticipate postflood restoration

Sensitivity: Increased hazard trees that threaten people and infrastructure.

Strategy: Prevent the development of and reduce risks associated with hazard trees. 

• Consider increasing use of pheromone 

treatments to protect trees in campgrounds, high-value habitats, and after floods

• Coordinate with entomologists• Increase internal education about increasing hazard tree risk

• Develop options, triggers, and methods for 

more aggressive management of hazard trees
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general technical report pnw-gtr-892 Table 5.4—Sensitivities of vegetation management to invasive species; adaptation strategies and tactics to reduce impacts Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needs Sensitivity: Increased potential for exotic species establishment. Strategy: Prevent invasive plants from establish- ing after disturbances. • Include invasive species prevention strategies in all projects • Inventory regularly to detect new populations and species • Coordinate invasive species management, funding, and program support between agencies Short term Exotic Plant Management plan (North Cascades National Park [NOCA]) and U.S. Department of Agriculture Forest Service (USDA FS) Region 6 Invasive Species Management Plan Interagency collaboration through North Cascadia Adaptive Partnership

Partner with Washington Weed Management Areas, Pacific Northwest Invasive Plant Council

Lack of funding and institutional support for integrated invasive species management

Identification of locations that are more vulnerable to invasive species establishment after disturbances

Strategy: Prevent widespread outbreaks of invasive species or pathogens. 

• Plan for extreme events and events with low 

probability 

• Maintain permits for aggressive treatment of 

invasive species (e.g., burning and herbicide)

Short term Invasive species management program (NOCA)

USDA FS Region 6 invasive species management plan

Strategy: Increase resilience by promoting native genotypes and adapted genotypes of native species. 

• Consider assisted migration (nonreserve)• Emphasize use of plant species that will

be robust to climate change in restoration projects

• Plant genetically adapted species from

appropriate seed zones

Long term Coordination of seed selection 

and propagation from one site to another

Institutional resistance to assisted migration (National Park Service)Uncertainty in the effects of implementing assisted migration

Test for viability of using rare plants in restoration projectsResearch on effects and methods for assisted migration, including nontree species
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Adapting vegetation management to climate change will require considering 

the effects of more floods on riparian vegetation (table 5.3). Committing restoration 

resources to locations that are likely to flood more frequently could be counter-productive and priorities may need to shift to areas with lower flood risk (Littell et al. 

2012). Restoring native vegetation in the floodplain is a complementary adaptation 

strategy for mitigating flood impacts on roads and infrastructure (see chapter 4) 

and reducing the effects of warmer stream temperatures on cold-water fish (see 

chapter 7). More flooding may increase opportunities for invasive species to establish in the floodplain, which could require more aggressive control than is currently 

used. The additional emergency resources that are available after severe floods may 

provide resources to implement adaptation strategies for riparian vegetation, if the 

strategies are identified in management plans developed before 

the floods. 

Increased rates of all forest disturbances may create more hazard trees in 

developed areas, which can threaten lives and property. Managers may need to plan 

for more hazard trees and consider increasing use of antiaggregation pheromones 

to prevent the development of hazardous trees in developed areas after disturbances and to protect high-value resources. More coordination with entomologists 

can increase awareness of the risks associated with hazard trees. Managers may 

consider revising plans for hazard tree mitigation to include triggers for action and 

additional options for aggressive treatment of hazard trees.

Adaptation Options for Invasive Species Management 

Preventing establishment of invasive species after disturbance could be more challenging in a changing climate. Thus increased inventory and monitoring of invasive 

species and coordination among land management agencies may be necessary (table 

5.4). Currently, resources are not sufficient to manage all invasive species, making 

it necessary to prioritize. Prioritization will be even more important if new invasive 

species emerge as climate changes, and current priorities may need to change. 

Adaptation can be facilitated by planning for more severe and widespread outbreaks 

of currently invasive species and maintaining permits for aggressive treatments 

including herbicides and burning. The current invasive species management programs in the national forests and national parks provide opportunities to consider 

climate change in management of invasive species, and the NCAP can facilitate 

interagency collaboration. 

Proactive management may be necessary to prevent the establishment of 

invasive species that could contribute to vegetation type conversions (e.g., forest to 

Restoring native 

vegetation in the 

floodplain is a 

complementary 

adaptation strategy 

for mitigating flood 

impacts on roads and 

infrastructure.
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general technical report pnw-gtr-892 Table 5.5—Sensitivities of subalpine and alpine ecosystems to climate change; adaptation strategies and tactics to reduce impacts Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needs Sensitivity: Increased tree establishment at treeline, particularly west of the Cascade Mountain crest. Strategy: Increase knowledge of rates and patterns of tree establishment and regeneration failures. • Detect and attribute historical changes in tree distribution at tree line (Mount Rainier Na- tional Park [MORA], North Cascades National Park [NOCA]) • Monitor tree establishment patterns • Use climate change information to project changes in recreation use patterns in the alpine (MORA, NOCA)

• Expand geographic scope or enhance site

monitoring

Short term Increase collaboration with research

National Park Service (NPS) subalpine and alpine monitoring program

Sensitivity: Change in species composition, relative abundance, and species distribution patterns.

Strategy: Increase knowledge of patterns, characteristics, and rates of change in species distributions.

• Expand long-term monitoring programs Short term Coordinate among agencies to improve analysis of long-term changes 

in vegetation 

Limited resources to sustain long-term monitoring 

Sensitivity: Loss of subalpine areas for traditional uses of plant species. 

Strategy: Maintain or increase the extent of subalpine areas.

• Maintain huckleberry production through tree 

removal and prescribed fire

• Consult with tribes to understand historical 

patterns and current locations of huckleberry habitat

Short term Collaborate with research community and tribes 

Collaborate with commercial huckleberry growers

Methods to increase huckleberry production
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needsSensitivity: Reduction in size and hydroperiod of wetlands and changes in nutrient availability, productivity, and species composition.

Strategy: Maintain resilience of high-elevation wetlands.

• Monitor functionality of existing wetlands• Reduce direct human impact on sensitive 

wetland habitats

• Monitor changes in plant distribution especially regarding exotic species

Short term, long term

A greater understanding of distribution and function of high-elevation wetlands

Sensitivity: Increased whitebark pine mortality

Strategy: Increase resilience and resistance of whitebark pine populations to mountain pine beetle and white pine blister rust.

• Strategically use antiaggregation pheromones• Plant blister rust resistant stock• Continue to test rust resistant seedlings• Continue to establish permanent monitoring 

plots and share data

• Coordinate U.S. Department of Agriculture, 

Forest Service (USDA FS) and National Park Service efforts to collect cones and produce seedlings

Short term NPS whitebark pine monitoring 

programListing of whitebark pine under the Endangered Species Act may increase funding and management priority

Limited funding for facilities for production of blister rust resistant seedlings

Chemical ecology of mountain pine beetle to develop more effective antiaggregate pheromones

Table 5.5—Sensitivities of subalpine and alpine ecosystems to climate change; adaptation strategies and tactics to reduce impacts (continued)
162

general technical report pnw-gtr-892 Adaptation tactics Timeframes Implementation opportunities Barriers to implementation Information needs Sensitivity: Possible loss of relict or disjunct populations and rare species.

Strategy: Prevent loss of relict populations of vascular and nonvascular species.

• Increase seed collection and seed banks

(ex situ)

• Identify areas where relict plants could be 

established

Short term Coordinate with University of 

Washington RareCare program

Lack of coordinated special species status between NPS and USDA FS

Determine the distribution of relict or disjunct populationsResearch on genetic variability within species, adaptive potential, and the extent of potential ranges

Sensitivity: Increase in nonnative species with east-side habitats potentially more susceptible.

Strategy: Maintain integrity of native plant populations and prevent exotic species invasions. 

• Early detection, rapid response• Promote weed-free seed• Prevent nonnative plant introductions during 

projects 

• Ensure weed-free feed policies are included in 

planning documents

• Coordinate USDA FS and NPS weed-free seed 

standards and regulations 

• Expand weed-free feed list to include additional nonnative species

Short term, long-term

Restoration projects are opportunities to manage and prevent invasive species establishment and favor native speciesWork with stock user groups to promote use of weed-free feed and processed feed

No certified weed-free feed sources in WashingtonCurrent inventory monitoring programs are not designed to detect small outlier populations, which are the easiest to control

More information on current locations and distributions of nonnative species

Table 5.5—Sensitivities of subalpine and alpine ecosystems to climate change; adaptation strategies and tactics to reduce impacts (continued)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

shrub land or grassland), particularly after disturbance when invasive species often 

have a competitive advantage over native species. Assisted migration and planting 

genetically adapted tree species from appropriate seed zones could facilitate establishment of native plant species after disturbance (Littell et al. 2012). Currently, 

these adaptation tactics are more appropriate for nonreserves areas and would 

require that agencies address current institutional concerns regarding assisted 

migration and active management in reserves. Additional research is needed to 

reduce uncertainty associated with assisted migration and to identify and test the 

viability of planting species better adapted to a warmer climate. 

Adaptation Options for Managing Alpine and Subalpine 

Ecosystems 

Vegetation monitoring protocols implemented by the NPS will help detect changes 

in the distribution, composition, and structure of alpine and subalpine plant communities in MORA and NOCA (table 5.5). Current monitoring could be expanded 

to include phenology of focal species, interannual patterns in species abundance, 

demographics and productivity of high-elevation populations, tracking of species 

at the extremes of their ranges, assessment of adaptive capacity of high-elevation 

species (genetic and physiological), as well as greater attention to the causes of 

shifts in species distributions. This information can be used to prioritize and adapt 

high-elevation plant restoration projects to be effective in a changing climate and to 

identify species that may become rare or sensitive and thus require additional protective measures. Additional resources could be allocated to expand the timeframe 

of monitoring to better detect long-term trends. 

Climate change may make it difficult to protect and restore populations of 

whitebark pine. Current management to increase the resilience and resistance of 

whitebark pine to mountain pine beetle and blister rust, such as planting blister rust 

resistant seedlings and using antiaggregation pheromones, will be more important 

for maintaining populations as climate change exacerbates current threats to the 

species. Coordination among agencies in the NCAP can ensure that resources are 

strategically used to protect species throughout the region, rather than only within 

an individual ownership. Long-term permanent plots to monitor trends in whitebark 

pine populations and rates of blister rust infection and mortality can be used to 

detect climate-driven changes in the distribution and vigor of whitebark pine, blister 

rust, and mountain pine beetle. 

Warmer temperatures and reduced snowpack may require additional monitoring of high-elevation wetlands that will likely experience changes in hydroperiod 

Climate change may 

make it difficult to 

protect and restore 

populations of 

whitebark pine. 
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general technical report pnw-gtr-892

(i.e., integration of the factors that affect the water budget). Changes in hydroperiods have consequences for productivity, phenology, and species composition. Current efforts to define the extent and distribution of high-elevation wetlands will be 

important for establishing a baseline and to quantify future changes. Management 

to reduce current threats from human use could also increase resilience of wetlands 

to climate change. 

In the North Cascades, huckleberry (Vaccinium spp.) is an important food 

source for wildlife and a traditional resource for Native Americans. More favorable 

growing conditions for trees at higher elevations may increase tree encroachment 

into huckleberry habitat. More active management may be required to maintain 

huckleberry habitat in a changing climate, including tree removal and prescribed 

fire. Coordination with tribes can increase understanding of historical and current 

distributions of huckleberry habitat and use throughout the region. 

Acknowledgments

We thank members of the natural resource staffs at Mount Baker-Snoqualmie 

National Forest, Okanogan-Wenatchee National Forest, North Cascades National 

Park Complex, and Mount Rainier National Park for their expertise and input during workshops and subsequent discussions, including David Kendrick, Karen Kopper, Laura Martin, Lou Whiteaker, Mignonne Bivin, and Richy Harrod. We thank 

B. Bentz and J. Régnière for supplying projections from Bentz et al. (2010). We 

thank B. Rogers and D. Bachelet for making Rogers et al. (2011) data publicly available. We also thank several regional experts for their contributions to the vegetation 

workshop including, Paul Hessburg, David W. Peterson, Karen Ripley, and Jessica 

Halofsky. Karen Ripley and Aleksandar Dozic of the Washington Department of 

Natural Resources reviewed information on insects and pathogens and provided 

maps and figures (5.7 and 5.8) of data collected during the annual aerial survey. 

Jessica Halofsky, Becky Kerns, David Kendrick, Connie Mehmel, and Mignonne 

Bivin provided helpful reviews of this chapter. 

Literature Cited

Acker, S.A.; Woodward, A.; Boetsch, J.R. [et al.]. 2010. Forest vegetation 

monitoring protocol for the North Coast and Cascades Network. Natural 

Resource Report NPS/NCCN/NRR—2010/242. Fort Collins, CO: U.S. 

Department of the Interior, National Park Service. 304 p.

Agee, J.K. 1993. Fire ecology of Pacific Northwest forests. Washington, DC:

Island Press. 505 p.
165

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Alftine, K.J.; Malanson, G.P.; Fabre, D.B. 2003. Feed-back driven response to 

multidecadal climatic variability at an alpine treeline. Physical Geography. 24: 

520–534.

Arft, A.M.; Walker, M.D.; Gurevitch, J. [et al.]. 1999. Responses of tundra plants 

to experimental warming: meta-analysis of the international tundra experiment. 

Ecological Monographs. 69: 491–511.

Aubry, C.A.; Devine, W.; Shoal, R. [et al.]. 2011. Climate change and forest 

biodiversity: a vulnerability assessment and action plan for national forests in 

western Washington. Portland, OR: U.S. Department of Agriculture, Forest 

Service, Pacific Northwest Region. 130 p. plus appendixes. 

Bekker, M.F. 2005. Positive feedback between tree establishment and patterns of 

subalpine forest advancement, Glacier National Park, Montana, U.S.A. Arctic, 

Antarctic, and Alpine Research. 37: 97–107.

Bentz, B.J.; Régnière, J.; Fettig, C.J. [et al.] 2010. Climate change and bark 

beetles of the Western United States and Canada: direct and indirect effects. 

BioScience. 60: 602–613.

Bradley, B. 2009. Regional analysis of the impacts of climate change on cheatgrass 

invasion shows potential risk and opportunity. Global Change Biology. 15: 

196–208.

Brooks, M.L.; D’Antonio, C.M.; Richardson, D.M. [et al.]. 2004. Effects of 

invasive alien plants on fire regimes. BioScience. 54: 677–688. 

Canaday, B.B.; Fonda, R.W. 1974. The influence of subalpine snowbanks on 

vegetation pattern, production, and phenology. Bulletin of the Torrey Botanical 

Club. 101: 340–350.

Canonne, N.; Sgorbati, S.; Guglielmin, M. 2007. Unexpected impacts of climate 

change on alpine vegetation. Frontiers in Ecology and the Environment. 5: 

360–364.

Cansler, C.A. 2011. Drivers of burn severity in the northern Cascade Range, 

Washington, USA. Seattle: University of Washington. 128 p. M.S. thesis. 

Chapin, F.S., III; Shaver, G.R. 1985. Individualistic growth response of tundra 

plant species to experimental manipulations in the field. Ecology. 66: 564–576.

Chapin, F.S., III; Shaver, G.R.; Giblin, A.E. [et al.]. 1995. Responses of arctic 

tundra to experimental and observed changes in climate. Ecology. 76: 694–711.
166

general technical report pnw-gtr-892

Chmura, D.J.; Anderson, P.D.; Howe, G.T. [et al.]. 2011. Forest responses to 

climate change in the northwestern United States: ecophysiological foundations 

for adaptive management. Forest Ecology and Management. 261: 1121–1142.

Christensen, N.L.; Bartuska, A.M.; Brown, J.H. [et al.]. 1996. The report of the 

Ecological Society of America committee on the scientific basis for ecosystem 

management. Ecological Applications. 6: 665–691.

Churkina, G.; Running, S.W. 1998. Contrasting climatic controls on the estimated 

productivity of global terrestrial biomes. Ecosystems. 1: 206–215.

Churkina, G.; Running, S.W.; Schloss, A.L. [et al.]. 1999. Comparing global 

models of terrestrial net primary productivity (NPP): the importance of water 

availability. Global Change Biology. 5(suppl.1): 46–55.

Coops, N.C.; Waring, R.H. 2010. A process-based approach to estimate lodgepole 

pine (Pinus contorta Dougl.) distribution in the Pacific Northwest under climate 

change. Climatic Change. 105: 313–328.

Coops, N.C.; Waring, R.H. 2011. Estimating the vulnerability of fifteen tree 

species under changing climate in Northwest North America. Ecological 

Modelling. 222: 2119–2129.

Crawford, J. 2008. Multi-scale investigations of alpine vascular plant species in 

the San Juan Mountains of Colorado, USA GLORIA target region. Scientific 

Acta. 2: 65–69.

Dale, V.H.; Joyce, L.A.; McNulty, S. [et al.]. 2001. Climate change and forest 

disturbances. BioScience. 51: 724–734.

Douglas, G.W. 1970. A vegetation study in the subalpine zone of the western North 

Cascades, Washington. Seattle: University of Washington. 293 p. M.S. thesis. 

Douglas, G.W. 1972. Subalpine plant communities of the western North Cascades, 

Washington. Arctic and Alpine Research. 4: 147–166.

Douglas, G.W.; Bliss, L.C. 1977. Alpine and high subalpine plant communities 

of the North Cascades region, Washington and British Columbia. Ecological 

Monographs. 47: 113–150.

Dukes, J.S.; Mooney, H.A. 1999. Does global change increase the success of 

biological invaders? Trends in Ecology and Evolution. 14: 135–139.

Edwards, O.M. 1980. The alpine vegetation of Mount Rainier National Park: 

structure, development and constraints. Seattle: University of Washington. 560 p. 
167

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

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.

Endangered Species Act of 1973 [ESA]; 16 U.S.C. 1531–1536, 1538–1540.

Franklin, J.F.; Dyrness, C.T. 1988. Natural vegetation of Oregon and Washington. 

Corvallis, OR: Oregon State University Press. 464 p.

Gärtner, S.; Reynolds, K.M.; Hessburg, P.F. [et al.]. 2008. Decision support for 

evaluating landscape departure and prioritizing forest management activities in a 

changing environment. Forest Ecology and Management. 256: 1666–1676.

Germino, M.J.; Smith, W.K.; Resor, A.C. 2002. Conifer seedling distribution and 

survival in an alpine-treeline ecotone. Plant Ecology. 162: 157–168.

Grabherr, G.; Gottfried, M.; Pauli, H. 1994. Climate effects on mountain plants. 

Nature. 369: 448.

Halofsky, J.E.; Peterson, D.L.; O’Halloran, K.A.; Hawkins Hoffman, C. 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.

Harrod, R.J.; McRae, B.H.; Hart, W.E. 1999. Historical stand reconstruction in 

ponderosa pine forests to guide silvicultural prescriptions. Forest Ecology and 

Management. 114: 433–446.

Harsch, M.A.; Hulme, P.E.; McGlone, M.S.; Duncan, R.P. 2009. Are treelines 

advancing? A global meta-analysis of treeline response to climate warming. 

Ecology Letters. 12: 1040–1049.

Harte, J.; Shaw, R. 1995. Shifting dominance within a montane vegetation 

community—results of a climate-warming experiment. Science. 267: 876–880.

Haugo, R.D.; Halpern, C.B. 2010. Interactive effects of tree and herb cover on 

survivorship, physiology, and microclimate of conifer seedlings at the alpine 

tree-line ecotone. Botany. 88: 488–499.

Hellmann, J.J.; Byers, J.E.; Bierwagen, B.G.; Dunkes, J.S. 2008. Five potential 

consequences of climate change for invasive species. Conservation Biology. 22: 

534–543.

Henderson, J.A. 1974. Composition, distribution and succession of subalpine 

meadows in Mount Rainier National Park. Corvallis, OR: Oregon State 

University. 163 p. Ph.D. dissertation. 
168

general technical report pnw-gtr-892

Henderson, J.A.; Lesher, R.D.; Peterson, D.H.; Shaw, D.C. 1992. Field guide 

to the forested plant associations of the Mt. Baker-Snoqualmie National Forest. 

Tech. Pap. PNW R6-ECOL-TP-028-91. Portland, OR: U.S. Department of 

Agriculture, Forest Service, Pacific Northwest Region. 196 p.

Hessburg, P.F.; Agee, J.K.; Franklin, J.F. 2005. Dry forests and wildland fires of 

the inland Northwest, USA: contrasting the landscape ecology of pre-settlement 

and modern eras. Forest Ecology and Management. 211: 117–139. 

Hessburg, P.F.; Smith, B.G.; Salter, R.B. [et al.]. 2000. Recent changes 

(1930s–1990s) in spatial patterns of interior northwest forests, USA. Forest 

Ecology and Management. 136: 53–83.

Hicke, J.A.; Johnson, M.C.; Hayes, J.L.; Preisler, H.K. 2012. Effects of bark 

beetle-caused tree mortality on wildfire. Forest Ecology and Management. 271: 

81–90.

Hicke, J.A.; Logan, J.A.; Powell, J.; Ojima, D.S. 2006. Changing temperatures 

influence suitability for modeled mountain pine beetle (Dendroctonus 

ponderosae) outbreaks in the Western United States. Journal of Geophysical 

Research. 111: G02019. 

Holtmeier, F.K.; Broll, G. 2005. Sensitivity and response of northern hemisphere 

altitudinal and polar treelines to environmental change at landscape and local 

scales. Global Ecology and Biogeography. 14: 395–410.

Intergovernmental Panel on Climate Change [IPCC]. 2007. Summary for 

policymakers, in climate change 2007: impacts, adaptation and vulnerability. 

Contribution of working group II to the fourth assessment report of the 

Intergovernmental Panel on Climate Change. In: Parry, M.L.; Canziani, O.F.; 

Palutikof, P.J. [et al.]. Cambridge United Kingdom: University. Press: 7–22.

Jurasinski, G.; Kreyling, J. 2007. Upward shift of alpine plants increases floristic 

similarity of mountain summits. Journal of Vegetation Science. 18: 711–718.

Kashian, D.M.; Romme, W.H.; Tinker, D.B. [et al.]. 2006. Carbon storage on 

landscapes with stand-replacing fires. Bioscience. 56: 598–606.

Kearney, M.S.; Luckman, B.H. 1983. Holocene timberline fluctuations in Jasper 

National Park, Alberta. Science. 221: 261–263.

Keeley, J.E. 2006. Fire management impacts on invasive plants in the Western 

United States. Conservation Biology. 2: 375–384.
169

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Klanderud, K. 2008. Species-specific responses of an alpine plant community 

under simulated environmental change. Journal of Vegetation Science. 19: 

363–372.

Klanderud, K.; Totland, Ø. 2005. Simulated climate change altered dominance 

hierarchies and diversity of an alpine biodiversity hotspot. Ecology. 86: 

2047–2054.

Klasner, F.L.; Fagre, D.B. 2002. A half century of change in alpine treeline 

patterns at Glacier National Park, Montana, U.S.A. Arctic, Antarctic, and 

Alpine Research. 34: 49–56.

Kliejunas, J.T. 2011. A risk assessment of climate change and the impact of forest 

diseases on forest ecosystems in the Western United States and Canada. Gen. 

Tech. Rep. PSW-GTR-236. Albany, CA: U.S. Department of Agriculture, Forest 

Service, Pacific Southwest Research Station. 70 p.

Klopfenstein, N.B.; Kim, M.-S; Hanna, J.W. [et al.]. 2009. Approaches to 

predicting potential impacts of climate change on forest disease: an example 

with Armillaria root disease. Res. Pap. RMRS-RP-76. Fort Collins, CO: U.S. 

Department of Agriculture, Forest Service, Rocky Mountain Research Station. 

10 p.

Körner, C.; Paulsen, J. 2004. A world-wide study of high altitude treeline 

temperatures. Journal of Biogeography. 31: 713–732.

Kurz, W.A.; Dymond, C.C.; Stinson, G. [et al.]. 2008. Mountain pine beetle 

and forest carbon feedback to climate change. Nature. 452: 987–990.

LaMarche, V.C. 1973. Holocene climatic variations inferred from treeline 

fluctuations in the White Mountains, California. Quaternary Research.

3: 632–660.

Law, B.; Falge, E.; Baldocchi, D. [et al.]. 2002. Environmental controls over 

carbon dioxide and water vapor exchange of terrestrial vegetation. Agricultural 

and Forest Meteorology. 113: 97–120.

Lenihan, J.M.; Bachelet, D.; Neilson, R.P.; Drapek, R. 2008. Simulated response 

of conterminous United States ecosystems to climate change at different levels 

of fire suppression, CO2 emission rate, and growth response to CO2. Global and 

Planetary Change. 64: 16–25.
170

general technical report pnw-gtr-892

Littell, J.S.; Elsner, M.M.; Mauger, G.S. [et al.]. 2011. Regional climate and 

hydrologic change in the northern U.S. Rockies and Pacific Northwest: internally 

consistent projections of future climate for resource management. Preliminary 

project report, USDA FS JVA 09-JV-11015600-039. Seattle, WA: University of 

Washington, Center for Science in the Earth System, Joint Institute for the Study 

of the Atmosphere and Ocean, Climate Impacts Group. http://cses.washington.

edu/picea/USFS/pub/Littell_etal_2010/Littell_etal._2011_Regional_Climatic_

And_Hydrologic_Change_USFS_USFWS_JVA_17Apr11.pdf. (15 April 2013). 

Littell, J.S.; Gwozdz, R. 2011. Climatic water balance and regional fire years 

in the Pacific Northwest, USA: linking regional climate and fire at landscape 

scales. Ecological Studies 213. In: McKenzie, D.; Miller, C.M.; Falk, D.A., eds. 

The landscape ecology of fire. Dordrecht, The Netherlands: Springer: 117–142. 

Chapter 5. 

Littell, J.S.; McKenzie, D.; Peterson, D.L.; Westerling, A.L. 2009. Climate 

and wildfire area burned in western U.S. ecoprovinces, 1916–2003. Ecological 

Applications. 19: 1003–1021.

Littell, J.S.; Oneil, E.E.; McKenzie, D. 2010. Forest ecosystems, disturbance, and 

climatic change in Washington state, USA. Climatic Change. 102: 129–158.

Littell, J.S.; Peterson, D.L.; Millar, C.; O’Halloran, K.A. 2012. U.S. National 

Forests adapt to climate change through science-management partnerships. 

Climatic Change. 110: 269–296.

Loarie, S.R.; Duffy, P.B.; Hamilton, H. [et al.]. 2009. The velocity of climate 

change. Nature. 462: 24–31.

Logan, J.A.; Macfarlane, W.W.; Wilcox, L. 2010. Whitebark pine vulnerability 

to climate-driven mountain pine beetle disturbance in the Greater Yellowstone 

Ecosystem. Ecological Applications. 20: 895–902.

Logan, J.A.; Powell, J.A. 2001. Ghost forests, global warming, and the mountain 

pine beetle (Coleoptera: Scolytidae). American Entomologist. 47: 160–173.

Malanson, G.P.; Butler, D.R.; Fagre, D.B. [et al.]. 2007. Alpine treeline of 

western North America: linking organism to landscape dynamics. Physical 

Geography. 28: 378–396.

Markgraf, V.; Scott, L. 1981. Lower timberlines in central Colorado during the 

last 15,000 yr. Geology. 9: 231–234.
171

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

McKenney, D.W.; Pedlar, J.H.; Lawrence, K. [et al.]. 2007. Potential impacts 

of climate change on the distribution of North American trees. BioScience. 57: 

939–948.

McKenney, D.W.; Pedlar, J.H.; Rood, R.B.; Price, D. 2011. Revisiting projected 

shifts in the climate envelopes of North American trees using updated general 

circulation models. Global Change Biology. 17: 2720–2730.

McKenzie, D.; Gedalof, Z.; Peterson, D.L.; Mote, P. 2004. Climatic change, 

wildfire, and conservation. Conservation Biology. 18: 890–902.

McKenzie, D.; Peterson, D.L.; Littell, J.S. 2009. Global warming and stress 

complexes in forests of western North America. In: Bytnerowicz, A.; Arbaugh, 

M.; Andersen, C.; Riebau, A., eds. Developments in Environmental Science 8. 

Amsterdam, the Netherlands: Elsevier: 319–338. 

McKenzie, D.; Peterson, D.W.; Peterson, D.L.; Thornton, P.E. 2003. Climatic 

and biophysical controls on conifer species distributions in mountain forests of 

Washington state, USA. Journal of Biogeography. 30: 1093–1108.

Millar, C.I.; Stephenson, N.L.; Stephens, S.L. 2007. Climate change and forests 

of the future: managing on the face of uncertainty. Ecological Applications. 17: 

2145–2151.

Millennium Ecosystem Assessment [MEA]. 2005. Ecosystems and human wellbeing: synthesis. Washington, DC: Island Press. 137 p.

Miller, C.; Abatzoglou, J.; Brown, T.; Syphard, A.D. 2011. Wilderness fire 

management in a changing environment. Ecological Studies 213. In: McKenzie, 

D.; Millar, C.M.; Falk, D.A., eds. The landscape ecology of fire. Dordrecht; New 

York: Springer: 269–294. Chapter 11. 

Mote, P.W.; Hamlet, A.F.; Clark, M.P.; Lettenmaier, D.P. 2005. Declining 

mountain snowpack in western North America. Bulletin of the American 

Meteorological Society. 86: 39–49.

Mote, P.; Hamlet, A.; Salathé, E. 2008. Has spring snowpack declined in the 

Washington Cascades? Hydrology and Earth Systems Sciences. 12: 193–206.

Mote, P.W.; Salathé, E.P. 2010. Future climate in the Pacific Northwest. Climatic 

Change. 102: 29–50.

National Environmental Policy Act of 1969 [NEPA]; 42 U.S.C. 4321 et seq.
172

general technical report pnw-gtr-892

Nemani, R.R.; Keeling, C.D.; Hashimoto, H. [et al.]. 2003. Climate driven 

increases in terrestrial net primary production from 1982 to 1999. Science. 

300: 1560–1563.

Odland, A.; Høitmomt, T.; Olsen, S.L. 2010. Increasing vascular plant richness 

on 13 high mountain summits in southern Norway since the early 1970s. Arctic, 

Antarctic, and Alpine Research. 42: 458–470.

Oren, R.; Ellsworth, D.; Johnson, K. [et al.]. 2001. Soil fertility limits carbon 

sequestration by forest ecosystems in a CO2-enriched atmosphere. Nature. 411: 

469–472.

Parry, M.L.; Canzianai, O.F.; Palutikof, J.P. [et al.], eds. 2007. Climate change 

2007: impacts, adaptation and vulnerability—a 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.

Pauchard, A.; Kueffer, C.; Dietz, H. [et al.]. 2009. Ain’t no mountain high 

enough: plant invasions reaching new elevations. Frontiers in Ecology and the 

Environment. 7: 479–486.

Pauli, H.; Gottfried, M.; Reiter, K. [et al.]. 2007. Signals of range expansions and 

contractions of vascular plants in the high Alps: observations (1944–2004) at the 

GLORIA master site Schrankogel, Tyrol, Austria. Global Change Biology. 13: 

147–156.

Perry, D.A.; Hessburg, P.I.; Skinner, C.N. [et al.]. 2011. The ecology of mixed 

severity fire regimes in Washington, Oregon, and Northern California. Forest 

Ecology and Management. 262: 703–717.

Peterson, D.L.; Halofsky, J.E.; Johnson, M.C. 2011a. Managing and adapting 

to changing fire regimes in a warmer climate. In: McKenzie, D.; Millar, C.M.; 

Falk, D.A., eds. The landscape ecology of fire. Dordrecht; New York: Springer: 

Ecological Studies 213. Chapter 10. 

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al.]. 2011b. Responding to climate 

change in national forests: a guidebook for developing adaptation options. Gen. 

Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 109 p.

Price, M.V.; Walker, N.M. 1998. Effects of experimental warming on plant 

reproductive phenology in a subalpine meadow. Ecology. 79: 1261–1271.

Price, M.V.; Walker, N.M. 2000. Responses of subalpine meadow vegetation to 

four years of experimental warming. Ecological Applications. 10: 811–823.
173

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Raymond, C.L.; McKenzie, D. 2012. Carbon dynamics of forests in Washington, 

USA: 21st century projections based on climate-driven changes in fire regimes. 

Ecological Applications. 22: 1589–1611.

Rehfeldt, G.E.; Crookston, N.L.; Warwell, M.V.; Evans, J.S. 2006. Empirical 

analyses of plant-climate relationships for the western United States. 

International Journal of Plant Sciences. 167: 1123–1150.

Rehfeldt, G.E.; Ferguson, D.E.; Crookston, N.L. 2008. Quantifying the 

abundance of co-occurring conifers along Inland Northwest (USA) climate 

gradients. Ecology. 89: 2127–2139.

Resler, L.M.; Tomback, D.F. 2008. Blister rust prevalence in krummholz 

whitebark pine: implications for treeline dynamics, northern Rocky Mountains, 

Montana, USA. Arctic, Antarctic, and Alpine Research. 40: 161–170.

Reynolds, K.M.; Hessburg, P.F. 2005. Decision support for integrated landscape 

evaluation and restoration planning. Forest Ecology and Management. 207: 

263–278.

Rochefort, R.; Bivin, M.; Boetsch, J.R. [et al.]. 2012. Alpine and subalpine 

vegetation monitoring protocol for the North Coast and Cascades Network. 

Natural Resource Rep. NPS/NCCN/NRR—2012/570. Fort Collins, CO: National 

Park Service. 328 p.

Rochefort, R.M.; Little, R.L.; Woodward, A.; Peterson, D.L. 1994. Changes 

in the distribution of subalpine conifers in western North America: a review of 

climate and other factors. The Holocene. 4: 89–100.

Rogers, B.M.; Neilson, R.P.; Drapek, R. [et al.]. 2011. Impacts of climate change 

on fire regimes and carbon stocks of the U.S. Pacific Northwest. Journal of 

Geophysical Research. 116: G03037.

Ryan, M.G.; Harmon, M.E.; Birdsey, R.A. [et al.]. 2010. A synthesis of the 

science on forests and carbon for US forests. Issues in Ecology. 13: 1–17.

Salathé, E.P.; Leung, L.R.; Qian, Y.; Zhang, Y. 2010. Regional climate model 

projections for the State of Washington. Climatic Change. 102: 51–75.

Savage, M.; Mast, J.N. 2005. How resilient are southwestern ponderosa pine 

forests after crown fires? Canadian Journal of Forest Research. 35: 967–977.

Smith, N.; Deal, R.; Kline, J. [et al.]. 2011. Ecosystem services as a framework 

for forest stewardship: Deschutes National Forest overview. Gen. Tech. Rep. 

PNW-GTR-852. Portland, OR: U.S. Department of Agriculture, Forest Service, 

Pacific Northwest Research Station. 46 p.
174

general technical report pnw-gtr-892

Smith, W.K.; Germino, M.J.; Johnson, D.M.; Reinhardt, K. 2009. The altitude 

of alpine treeline: a bellwether of climate change effects. The Botanical Review. 

75: 163–190

Smithwick, E.A.H.; Harmon, M.E.; Remillard, S. [et al.]. 2002. Potential 

upper bounds of carbon stores in forests of the Pacific Northwest. Ecological 

Applications. 12: 1303–1317.

Spies, T.A.; Hemstrom, M.A.; Youngblood, A.; Hummel, S. 2006. Conserving 

old-growth forest diversity in disturbance-prone landscapes. Conservation 

Biology. 20: 351–362. 

Stephenson, N.L. 1990. Climatic control of vegetation distribution: the role of the 

water balance. American Naturalist. 135: 649–670.

Stueve, K.M.; Cerney, D.L.; Rochefort, R.M.; Kurth, L.L. 2009. Post-fire tree 

establishment patterns at the alpine treeline ecotone: Mount Rainier National 

Park, Washington, USA. Journal of Vegetation Science. 20: 107–120.

Survey and Manage Settlement Agreement. 2011. Conservation Northwest v. 

Sherman, No. 08-CV-1067-JCC. (W.D. Wash.).

Theurillat, J.P.; Guisan A. 2001. Potential impact of climate change on vegetation 

in the European Alps: a review. Climatic Change. 50: 77–109.

U.S. Department of Agriculture, Forest Service [USDA FS]. 1998. Eastside 

screens: interim direction for the management of national forest lands within 

the Pacific Northwest Region. Portland, OR: Pacific Northwest Region.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2005. Pacific 

Northwest Region invasive plant program: preventing and managing invasive 

plants: record of decision. Portland, OR: Pacific Northwest Region. 64 p. 

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012a. The 

Okanogan-Wenatchee National Forest restoration strategy: adaptive ecosystem 

management to restore landscape resiliency. 2012 Version. Portland, OR: Pacific 

Northwest Region. 119 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012b. Forest 

inventory and analysis national program. http://www.fia.fs.fed.us/. (8 July 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012c. Forest 

health monitoring—West Coast region. http://www.fs.usda.gov/detail/r6/forestgrasslandhealth/insects-diseases/?cid=fsbdev2_027369. (8 July 2012).
175

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

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 the 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. Department of the Interior, Fish and Wildlife Service [USFWS]. 2008. 

Final recovery plan for the northern spotted owl (Strix occidentalis caurina). 

Portland, OR: Region 1, Ecological Services. 142 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2005.

Mount Rainier National Park fire management plan environmental assessment. 

Ashford, WA. 145 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2006. 

Management policies 2006. Washington, DC: U.S. Government Printing Office. 

179 p. 

U.S. Department of the Interior, National Park Service [USDI NPS]. 2007.

North Cascades National Park Complex fire management plan. Rev. 2010.

Sedro-Woolley, WA. 

U.S. Department of the Interior, National Park Service [USDI NPS]. Mount 

Rainier National Park final general management plan environmental impact 

statement. Ashford, WA. 420 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2011b. 

North Cascades National Park Complex invasive nonnative plant management 

environmental assessment. Sedro-Woolley, WA. 250 p.

Vose, J.M.; Peterson, D.L.; Patel-Weynand, T., eds. 2012. The effects of 

climatic variability and change on forest ecosystems: a comprehensive science 

for the U.S. forest sector. Gen. Tech. Rep. PNW-GTR-870. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Research Station. 

265 p.

Walker, M.D.; Wahren, H.A.; Hollister, R.D. [et al.]. 2006. Plant community 

responses to experimental warming across the tundra biome. Proceedings of the 

National Academy of Sciences of the United States of America. 103: 1342–1346.

Walther, G.-R.; Beissner, S.; Burga, C.A. 2005. Trends in the upward shift of 

alpine plants. Journal of Vegetation Science. 16: 541–548.
176

general technical report pnw-gtr-892

Walther, G.-R.; Post, E.; Convey, P. [et al.]. 2002. Ecological responses to recent 

climate change. Nature. 416: 389–395.

Ward, K.; Shoal, R.; Aubrey, C. 2006. Whitebark pine in Washington and 

Oregon: a synthesis of current studies and historical data. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Region. 40 p. 

Waring, R.H.; Franklin, J.F. 1979. Evergreen coniferous forests of the Pacific 

Northwest. Science. 204: 1380–1386. 

Washington Department of Natural Resources [WADNR]. 2012a. Forest 

health highlights in Washington—2011. Olympia, WA: State of Washington, 

Department of Natural Resources, Forest Health Program. 36 p.

Washington Department of Natural Resources. 2012b. List of vascular plants 

tracked by the Washington Natural Heritage Program. http://www1.dnr.wa.gov/

nhp/refdesk/lists/plantrnk.html. (18 April 2003).

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

Ziska, L.H.; Reeves, J.B.; Blank, B. 2005. The impact of recent increases in 

atmospheric CO2

 on biomass production and vegetation retention of cheatgrass 

(Bromus tectorm): implications for fire disturbance. Global Change Biology. 11: 

1325–1332. 
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Introduction

The North Cascadia Adaptation Partnership (NCAP) held a 2-day workshop on 

adapting wildlife and wildlife management to climate change in the North Cascades. The objective of the workshop was to convene scientists and land managers 

concerned about climate change effects on wildlife. Forty-five people participated, 

including resource managers and scientists from the U.S. Department of Agriculture Forest Service (USDA FS), U.S. Department of Interior National Park Service 

(NPS) and Fish and Wildlife Service (USFWS) (including the Great Northern and 

North Pacific Landscape Conservation Cooperatives), Washington State Department of Fish and Wildlife (WDFW), University of Washington, Seattle Public 

Utilities, Western Transportation Institute, Conservation Northwest, and National 

Parks and Conservation Association. Workshop objectives were to (1) assess the 

sensitivity and vulnerability of wildlife species and habitats to projected changes in 

climate, (2) review current wildlife management priorities and share management 

approaches that have already considered climatic variability and change, (3) use 

the latest scientific information on climate change effects on wildlife and habitat to 

identify adaptation options that can be implemented by the forests and parks, and 

(4) identify opportunities to build partnerships and develop adaptation options that 

cross jurisdictional boundaries.

The workshop included presentations on the latest science on climate change 

effects on species distributions, demography, and phenology. Resource managers and scientists from each of the national forests and national parks in NCAP 

presented current practices for managing and monitoring wildlife populations and 

habitat. Representatives from the WDFW and the North Pacific and Great Northern

1 Joshua J. Lawler is an associate professor of landscape ecology and conservation, 

Maureen E. Ryan is a research associate, and Michael J. Case is a Ph.D. candidate, 

University of Washington, School of Environmental and Forest Sciences, Box 352100, 

Seattle, WA 98195; Crystal L. Raymond is a climate change strategic advisor, City of 

Seattle, Seattle City Light, 700 5th Avenue, Seattle, WA 98124 (formerly research biologist, 

U.S. Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire Sciences 

Lab, Seattle, WA); and Regina M. Rochefort is a science advisor, North Cascades National 

Park Complex, 2105 State Route 20, Sedro-Woolley, WA 98284. 

Chapter 6: Climate Change, Wildlife, and Wildlife 

Habitat in the North Cascade Range

Joshua J. Lawler, Crystal L. Raymond, Maureen E. Ryan, Michael J. Case, and 

Regina M. Rochefort1
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Landscape Conservation Cooperatives presented current efforts within their 

agencies to adapt management to a changing climate. Presentations on the second 

day focused on current research in the region on wildlife habitats that are likely 

to be affected by a changing climate including wetlands, fire-adapted forests, and 

habitat connectivity (Washington Wildlife Habitat Connectivity Working Group 

[WHCWG] 2011). 

Vulnerability Assessment for Wildlife and Habitat

Vulnerability to climate change can be defined as the likelihood that a system or 

species will experience a change of state as a result of projected changes in climate. 

For an ecological system, such a change could be altered species composition, 

ecosystem function, or a change in a disturbance regime. For a species, a change 

of state could be a change in population growth rate, abundance, or distribution. 

Vulnerability is a function of exposure, sensitivity, and adaptive capacity (Glick et 

al. 2011) (see chapter 1). Exposure is a measure of the degree to which the climate 

will change. Sensitivity is a measure of how much of a change in climate a species 

or system can endure before changing state. Adaptive capacity is an estimate of the 

ability of a species or system to change in such a way that allows it to persist as the 

climate changes. Ultimately, information gathered through a vulnerability assessment can be used to inform adaptation planning.

In its simplest form, exposure is a measure of how much climatic conditions 

will likely change. Thus, projected changes in temperature and precipitation as 

described in chapter 3 provide a basic indication of the likely exposure of species 

and habitats in the NCAP region. However, for a given species or ecological system, 

some climate-related factors will be more important for exposure than others. For 

example, for the wolverine (Gulo gulo L.), a species for which snow is important, 

snowpack is a critical component of exposure and thus projected changes in 

snowpack are useful for assessing its vulnerability (e.g., McKelvey et al. 2011).2

For amphibian species, higher temperature and lower summer precipitation may 

be less important than changes in wetland hydroperiod that they produce. Thus, 

some aspects of exposure are more nuanced, and projecting them involves looking 

beyond projected changes in temperature and precipitation. Chapter 4 describes

2 Snowpack is measured as snow depth or snow water equivalent (SWE), the water content 

of the snowpack. For comparisons, SWE on April 1 is commonly used because it corresponds to the date of peak SWE in many areas and is correlated with summer water supply 

in the PNW. Timing of snowmelt in spring can also be an important indicator of wildlife 

habitat and ecosystem processes (see chapter 4 of this report for a detailed discussion of 

snowpack).
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projected changes in snowpack and hydrology, some of which are relevant for 

wildlife species and habitat.

Sensitivity is an inherent measure of how much climate change a species 

or system can tolerate. For any species, sensitivity is a function of many factors 

including physiology, life history traits, and trophic and competitive relationships. 

For example, some species can function under a wide range of temperatures—these 

species are likely to be less sensitive to climate change than are species that can 

tolerate only a narrow range of temperatures. Species that have short generation 

times, produce many offspring, and have low parental investment are thought to 

recover quickly from large environmental changes. Thus, these species may be less 

sensitive to climate change than species with long generation times, few offspring, 

and high parental investment. In addition, species that are specialists with respect 

to habitat or food requirements will likely be more sensitive to climate change than 

species that are able to use a wider variety of environments and food resources. The 

sections below describe general climate change effects on species and habitats in 

the North Cascades, integrating components of sensitivity and exposure. Additional 

information on the inherent sensitivity of species of concern in the region was 

gathered during the workshop.

Adaptive capacity can be difficult to assess. The factors that define adaptive 

capacity can be considered (1) inherent or (2) contextual or external. Inherent 

adaptive capacity is determined by the inherent capacity of the species or habitat 

to change in response to altered climatic conditions. This capacity is affected by 

dispersal ability (the ability to move to track changing conditions), phenotypic 

plasticity (the ability to change behavior or morphology in response to changing 

conditions), and evolutionary capacity (the ability to evolve in the face of climate 

change). Contextual or external aspects of adaptive capacity include landscape patterns and conditions that facilitate or serve as barriers to movement, as well as the 

capacity of managers to improve the ability of species or habitat to adapt to climate 

change. For example, the influence of nonclimatic stressors is one component of 

adaptive capacity—species or habitats with fewer nonclimatic stressors are likely 

to have a greater capacity to adapt to changes in climate. An assessment of current 

wildlife management objectives and practices describes another component of 

adaptive capacity by indicating (1) how current management practices can improve 

the ability of species or habitats to adapt, and (2) which objectives may be difficult 

to achieve in a changing climate. We also discuss barriers and opportunities for 

implementing adaptation strategies, which indicates another component of adaptive capacity, namely the institutional adaptive capacity of the national forests and 

national parks in the NCAP.

For any species, 

sensitivity is a function 

of many factors 

including physiology, 

life history traits, and 

trophic and competitive 

relationships. 
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Effects of Climate Change on Wildlife Species

Climate change is already affecting wildlife in multiple ways. Many species are 

shifting their distributions in directions and at rates that are consistent with recent 

changes in climate, and some species are experiencing shifts in the timing of 

ecological events (e.g., migration, breeding, or hatching) (Parmesan 2006). Species 

are likely to be physiologically affected by climate change in other ways as well, 

including changes in metabolic and growth rates, altered reproductive output, and 

changes in the frequency of heat stress or cold-related injuries or mortality (Schneider et al. 2002).

As climate changes, species will also be more or less indirectly affected by climate change. Climate change will alter interspecific interactions, potentially changing predator-prey dynamics, competitive relationships, the effects of parasites and 

diseases, and facilitative interactions (Kareiva et al. 1993, Schneider et al. 2002). 

Climate change will also alter plant species distributions, plant communities, and 

in turn habitat for many species. Climate-induced changes in fire and hydrologic 

regimes will have additional effects on habitat, food resources, and hence reproduction and mortality rates of many species. In addition, many wildlife species will 

likely be affected by other nonclimatic stressors that themselves will be affected by 

climate change. For example, many invasive species are expected to benefit from 

climate change, potentially resulting in increased effects on native species (Dukes 

and Mooney 1999). There may also be more subtle effects of climate change on 

wildlife including increases in human-wildlife interactions as people change their 

behavior (e.g., more visits to higher elevation parks as summer temperatures rise).

Not all species will respond to climate change in the same way or even in 

perceptible ways. Some species will be less vulnerable to climate change because 

they are generalists, can more easily disperse to new locations, occupy habitats that 

are likely to be more resilient to climate change, have the evolutionary potential or 

the phenotypic plasticity to adapt to changes, or are less physiologically sensitive to 

changes in temperature and moisture. On the other hand, species that are specialists, limited to narrow climatic niches or rare habitats, limited in their dispersal 

abilities, lacking in phenotypic plasticity, tightly tied to a particular disturbance 

regime (e.g., fire return interval), or heavily affected by other stressors are likely to 

be more vulnerable to climate change.
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Physiological Effects

Many of the species in the North Cascades region are adapted to relatively cool, 

moist environments and, in particular, cold wet winters and warm dry summers. 

This basic climatic pattern will not change, and may be reinforced by projected 

increases in winter precipitation and decreases in summer precipitation (see chapter 

3), and the higher temperature projected for the North Cascades, coupled with drier 

summers, will directly affect many species in the region. 

Although relatively few species in the North Cascades exist at the warm or dry 

extreme of their physiological limits, several species are physiologically limited 

by warm temperatures and dry summer conditions. For example, the American 

pika (Ochotona princeps Richardson) is sensitive to warm temperatures and has 

recently disappeared from several lower elevation sites in parts of its range outside 

of the North Cascades (Beever et al. 2003). Many amphibian species are likely to 

be sensitive to increases in temperature and the drier conditions that are projected 

for summer months (Blaustein et al. 2010). Amphibians, in general, are expected to 

be some of the most sensitive species to climate change because of their permeable 

skins and moisture requirements, as well as their biphasic life histories requiring 

water for breeding and upland habitats for other activities. Several cases of changes 

in climate affecting amphibians have been documented in other areas (e.g., warming and drying in tropical ecosystems), including suspected population and species extinctions (Pounds and Crump 1994, Pounds et al. 1999). Lower spring and 

summer precipitation, coupled with higher temperature, could shorten hydroperiods 

for many smaller ponds and wetlands. Such changes will reduce the availability of 

habitat for many amphibians, potentially fragmenting and isolating populations.

In general, higher temperature has the potential to increase metabolic rates, 

alter reproductive output, and affect animal behavior. As temperatures rise, some 

species, such as the pika, may be more restricted in the times that they can forage (Smith 1974). Decreased snowpack may also affect the pika by providing less 

insulation while they are in their burrows in the winter (Smith 1978). Pika populations have been extirpated from some low-elevation habitats in the Great Basin 

because of climatic stresses (Beever et al. 2003, 2010), but the effects of climate 

change on other populations are likely to vary with elevation and latitude within 

the geographic range of the species (Erb et al. 2011, Simpson 2009). Other species, 

such as grizzly bears (Ursus arctos horribilis Ord), may have shortened hibernation 

periods and thus spend more time out of the den and potentially in contact with 

people (Haroldson et al. 2002). 

Many amphibian 

species are likely to 

be sensitive to higher 

temperature and drier 

conditions in the 

summer.
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Phenological Effects

Many aspects of phenology (the timing of ecological events) are closely tied to 

climate. For animals, the timing of migration, emergence from hibernation, and 

breeding, nesting, and hatching (for insects) can all be tied to climatic triggers. 

For plants, bud burst, fruiting, and the loss of leaves in the fall can all be linked to 

climatic conditions. 

Increasing temperatures over the last half century have led to a shift in seasonality in some regions, including spring events occurring earlier in the year 

(Schwartz et al. 2006). These events include amphibians breeding, birds returning 

from migration, leaf out, and insects hatching (Parmesan and Yohe 2003, Root et 

al. 2003). In general, these events are occurring approximately 1 day earlier per 

decade in the Northern Hemisphere (Schwartz et al. 2006) and 1.5 days earlier per 

decade in the Western United States. There is mounting evidence that these shifts in 

phenology are not likely to be well synchronized, that is, not all events are shifting 

in time at the same rates.

This lack of synchrony has the potential to decouple ecological relationships. 

For example, if insect hatching advances at a faster rate than flowering or leaf out, 

crashes in insect populations may occur. Likewise, if birds return from migration 

before key insects hatch, bird reproduction or survival may decrease, and bird 

population might decline (Visser et al. 2011). In Colorado, yellow-bellied marmots 

(Marmota flaviventris Audubon & Bachman) emerged from hibernation 23 days 

earlier in 1999 than they did in 1975; however, there was not a similar shift in plant 

phenology because of high precipitation and snowpack during the same period 

(Inouye et al. 2000). Mismatches in the timing of breeding and availability of food 

resources may be more problematic for longer lived mammals because photoperiodic cueing for the onset of seasonal breeding is more common in these species 

than in shorter lived mammals (Bronson 2009). In the North Cascades, projected 

increases in temperature and decreases in snowpack may prevent the type of 

decoupling of food availability and emergence of hibernation that was seen in the 

Rocky Mountains. However, it is likely that there will be other mismatches in the 

timing of breeding, migration, hibernation, food resources, and other phenological 

characteristics.

For species with complex life cycles, such as amphibians and invertebrates, 

changes in the temperature and hydrology of wetlands may have substantial 

effects on phenology, recruitment, and life history selection (Matthews et al. 2010, 

McCaffery and Maxell 2010, Wellborn et al. 1996). Wetland habitats and species 

are already experiencing threats from habitat loss and fragmentation, disease, and 
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pollution (Stuart et al. 2004), all of which are likely to worsen with climate change 

(Corn 2005). The combined effects of warmer summer temperatures, changes in 

the seasonality of precipitation, and reduced snowpack may cause earlier drying 

of ephemeral streams and ponds and recession of shorelines (Corn 2005). Lower 

elevation populations may breed earlier in spring and experience increased variance 

in wetland depth and water quality. 

At higher elevations, reproduction depends on wetland hydroperiod and ice-free 

access. Earlier snowmelt in subalpine and alpine wetlands may increase access, but 

cool early-season temperatures may reduce the benefits of earlier access because 

of temperature-dependent embryonic growth and lags in primary productivity 

associated with temperature and day length that limit basal resources supporting 

aquatic food webs. Warmer summer temperatures could speed up larval development but could also increase embryonic and larval mortality if thermal tolerances 

are exceeded (Duarte et al. 2012). Altered hydroperiods will act as strong life 

history filters, particularly in higher elevation regions where many invertebrate 

and salamander species require multiple years for larval development (Stebbins 

2003, Wellborn et al. 1996). Fast-developing species such as western toads (Bufo 

boreas Baird & Girard) and ranid frogs may also experience increased larval 

mortality if ponds dry before tadpoles can metamorphose. Reduced exposure to 

severe winter conditions may enhance juvenile and adult survival in some regions 

(McCaffery and Maxell 2010). On the other hand, altered hydroperiod may increase 

the frequency of winter mortality in ponds or eliminate critical seep and spring 

overwintering habitats. Loss of insulating snowpack could also increase exposure 

to extreme temperatures or raise energetic costs of interrupted hibernation, causing 

negative effects on condition and survival (Hillman et al. 2009). 

Distributional Shifts

Some animal species appear to be moving in response to recent changes in climate 

(Parmesan 2006). In general, species are moving poleward in latitude and upward 

in elevation, and these movements are typically occurring at rates that correspond 

with changes in temperature. However, not all species are moving and not all are 

moving in ways that align with recent changes in climate (e.g., Moritz et al. 2008). 

Recent summaries of range shifts have found that these shifts have occurred 

approximately two to three times faster than those reported in previous studies 

(Chen et al. 2011), and that some plants and animals have moved upward in elevation at a rate of 11 m per decade and poleward in latitude at a rate of 16.9 km per 

decade.
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Many studies have also projected shifts in species distributions in response to 

projected changes in climate, and some species are projected to shift their distributions hundreds of kilometers by the end of the 21st century. These projections 

have been used to assess the potential degree of change in biotic communities. For 

example, across European ecoregions, averages of 45 to 63 percent change in the 

flora have been projected (Thuiller et al. 2005). Similarly, changes in fauna in the 

Western Hemisphere have been projected to be between 25 and 38 percent in any 

given location by the end of the 21st century (Lawler et al. 2009). These changes 

mean that in some places there will likely be different plant and animal communities in the future, and some places may see new communities with no historical 

analogs (Stralberg et al. 2009). 

These modeling efforts have their limitations. They may not account for lags 

in animal species movements associated with physical barriers or lack of suitable 

habitat. In some cases, plants will not move in response to climate change at the 

same rate as animals. For many forest-dependent animal species moving upward 

in elevation in the North Cascades, the ability to expand their distributions into 

elevations currently occupied by subalpine and alpine vegetation will be limited by 

the rate at which trees are able to move into these areas.

The North Cascades will likely serve as a refuge for many species attempting to 

move to higher elevations in search of cooler climates. Removing barriers to movement or otherwise fostering movement through the landscape to the more protected 

USDA FS and NPS lands will likely be an important strategy for protecting wildlife 

as temperatures rise. 

Interspecific Interactions

Climate-induced changes in phenologies and shifts in distributions have the potential to result in altered interspecific interactions. Because species have different 

temperature and moisture tolerances, different habitat needs, and different life 

histories, they will respond individualistically to climate change. Thus, a change in 

the distribution of a plant species will not necessarily be consistent with a similar 

shift in the distribution of its pollinators. Some species will likely be released 

from competitive relationships, whereas others will encounter new competitors. 

Still other species will likely experience changes in predation pressure and prey 

abundance.

Climate change is likely to affect many of the basic interactions that regulate 

ecological systems. For example, increases in atmospheric carbon dioxide (CO2)

concentrations and rising temperatures may disrupt mutualisms involving plants 

(e.g., pollination and seed dispersal), intensify pathogen infection rates, and 

The North Cascades 

will likely serve as 

a refuge for many 

species attempting 

to move to higher 

elevations in search

of cooler climates.
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enhance insect herbivory (Parmesan 2006, Traill et al. 2010, Tylianakis et al. 2008). 

In particular, parasite and disease outbreaks will likely become more frequent in a 

changing climate (Brooks and Hoberg 2007, Canto et al. 2009), partially because 

the ability of parasites and disease vectors to overwinter requires a specific range 

of climatic conditions (Garrett et al. 2006). As temperature increases, more of these 

parasites and their vectors will be able to survive through winter and thus may 

expand into areas in which they have previously been absent or at low densities. 

In addition, higher temperature and precipitation often correspond with greater 

diversity of diseases and higher disease transmission rates (Froeschke et al. 2010, 

Lafferty 2009). 

Amphibians are especially susceptible to disease outbreaks. Batrachochytrium 

dendrobatidis (Bd, chytrid fungus) (Kilpatrick et al. 2010), a fungal pathogen that is 

reducing amphibian populations globally (Stuart et al. 2004), is a particular concern 

for some amphibian species in the Pacific Northwest (Pearl et al. 2007). Although 

common in the Pacific Northwest, some amphibian populations survive despite 

high prevalence of Bd (Pearl et al. 2009), and the fungal pathogen has, to date, had 

limited impact in Washington state. Climatic associations with Bd pathogenicity 

are not yet well understood, with inconsistent impacts among regions and species (Blaustein et al. 2005, Ouellet et al. 2005). Susceptibility of aquatic larvae to 

Saprolegnia, other common fungal and bacterial infections, and aquatic parasites 

may increase at higher temperatures (Marcogliese 2001, Rohr et al. 2011). 

Interactions With Other Stressors

As climate changes, many species will continue to face other stressors, some of 

which will make species more or less susceptible to the effects of climate change. 

Some of these stressors will themselves be affected by climate change and thus 

may become more intense or, conversely, have less of an effect as a result of climate 

change. These stressors include invasive species, land use change, disturbance, 

contaminants, and human activity. 

Invasive species are expected to have an increasing effect on native species 

as climate changes (Dukes and Mooney 1999) because invasive species often 

outcompete native species in a changing climate (Verlinden and Nijs 2010, Willis 

et al. 2010). Many characteristics of invasive species that make them good invaders 

will also allow them to readily (or more readily than many native species) adapt to 

changing climates. For example, invasive species tend to be better able to change 

their phenologies than do native species, allowing invasive species to persist in a 

variety of climates (Willis et al. 2010). Good dispersal capability, high population 

growth rates, short generation times, and ability to tolerate a wide range of climatic 
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conditions will likely allow invasive species to track rapid changes in temperature 

and other climatic features (Hellmann et al. 2008, Schweiger et al. 2010). However, 

as with native plants, the distributions of some invasive species may also be limited 

by climate change (e.g., Bradley 2009).

In the North Cascades, climate change is likely to exacerbate the effects of 

invasive species in high-elevation wetlands.3 Introduced fish exclude many amphibians and invertebrates from lakes and ponds, shifting their distributions into shallower habitats where risks associated with climate change are disproportionately 

high (Bahls 1992, Hoffman et al. 2004, Knapp 1996, Knapp et al. 2001, Lacan et al. 

2008). Changing thermal and hydrologic conditions may naturally eliminate some 

populations of introduced fish; however, fish removals may be necessary in some 

cases to maintain adequate climate-resistant habitat for native amphibian species 

(Hoffman et al. 2004, Lacan et al. 2008). 

Land use change may exacerbate the effects of climate change on wildlife. Land 

use change can reduce habitat availability, fragment habitat, and reduce connectivity among wildlife populations. In the North Cascades, a legacy of past timber 

harvest, road building, and development of human settlements and infrastructure 

may reduce the ability of some species to move across the landscape to track changing climates. In addition, populations that are reduced because of habitat loss may 

be more susceptible to climate change. 

Climate-driven changes in disturbance regimes also have the potential to affect 

wildlife. The potential for increased area burned by wildfire and increased wildfire 

severity as temperatures continue to rise (Littell et al. 2009, Nitschke and Innes 

2008) (see chapter 5) in the North Cascades would indirectly affect wildlife by 

altering habitat and food resources. Increased area burned may catalyze projected 

changes in vegetation, as well as increase the area of forest in early-successional 

stages. This broad-scale modification of the landscape will increase habitat for 

species associated with early-successional habitat and decrease habitat for species 

associated with late-successional habitat.

Climate change has the potential to affect the delivery and availability of 

contaminants in some systems, particularly nutrients. For example, rain and fluxes 

of snowmelt transport nutrients from terrestrial landscapes into wetlands and other 

water bodies, where they drive the growth of periphyton and phytoplankton on 

which wetland food webs depend. In lakes and deeper wetlands, productivity may

3 Ryan, M.E.; Palen, W.J.; Adams, M.J. [N.d.]. Wetland ecosystems, climate change, 

and climate adaptation in the Pacific Northwest. On file with: M. Ryan, Rocky Mountain 

Research Station, 240 Prospect Road, Fort Collins, CO 80526.
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decline if thermal stratification weakens the water layer turnover that currently 

brings nutrients to the surface. In contrast, increased temperature may trigger algal 

blooms where nutrients are not limiting, with detrimental effects on oxygen availability for aquatic larvae or fish. Nutrient inputs and primary productivity affect 

the spectral characteristics of wetlands and ultraviolet radiation (UV) exposure to 

aquatic organisms (Calfee et al. 2006) although Pacific Northwest wetland species 

are currently well buffered from negative impacts of UV (Palen and Schindler 

2010). A greater risk is the mobilization and concentration of atmospherically 

deposited and soil-bound contaminants as glaciers melt, patterns of precipitation 

change, and summer water volume drops. High contaminant loads have been 

observed in wetlands in other alpine regions, and studies in the Cascade Range 

are underway (Hansen and Hoffman 2011).4 Because temperature and pH affect 

the toxicity of contaminants and rates of biological uptake, interactions between 

contamination and climate may affect wetland animals, and contaminant exposure 

may also increase susceptibility to disease.

Climate change may indirectly affect wildlife by altering human activities in 

national forests and national parks. For example, higher elevation systems with 

cooler climates may experience higher visitation rates in the future and potentially the need for additional infrastructure, resulting in more of human-animal 

interactions.

Effects of Climate Change on Wildlife Habitats 

Alpine and Subalpine Zones

Increasing temperatures will result in reduced snowpack and earlier snowmelt in 

alpine and subalpine regions of the North Cascades. These changes have the potential to alter vegetation, with higher tree density in the subalpine zone and potential 

movement of trees into the alpine zone in the long term. Projections of the MC1 

dynamic global vegetation model indicate reductions in much of the alpine tundra 

in NCAP national forests and national parks, except Mount Rainier National Park 

(MORA), and reductions in the area of subalpine forest by 2100 (see chapter 5). If 

future warming and lower snowpack lead to higher diversity of grasses and forbs, 

lower abundance of mosses and lichens, more invasive species, and increased height 

of trees, forage quantity and quality in the summer ranges for elk (Cervus elaphus

L.) may be altered.

4 Samora, B. 2011. Personal communication. Research coordinator, North Coast and 

Cascades Science Learning Network, Mount Rainier National Park, 55210 238th Avenue 

East, Ashford, WA 98304.
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Lower soil moisture caused by lower snowpack and summer precipitation may 

also lead to reduced huckleberry (Vaccinium spp.) production and hence reduced 

food resources for wildlife including grizzly bears and black bears (Ursus americanus Pallas). Tree encroachment may also contribute to reduced area of huckleberry 

habitat. The rate of change in productivity, tree encroachment, and change in the 

composition and structure of vegetation in general will likely be quite variable 

given different species-specific growth-limiting factors, plant growth strategies, 

and topographies (see chapter 5). 

Meadows

Wet montane meadows in the North Cascades, maintained by snowpack in the 

winter and short growing periods in the summers, will likely decrease in extent 

as lower snowpack and a longer growing season encourage tree establishment on 

meadow perimeters (see chapter 5). Although drier meadows in the North Cascades 

may also experience tree encroachment, these meadows may be maintained by 

higher fire occurrence. Loss of meadows would reduce habitat for American pikas, 

hoary marmots (Marmota caligata Eschscholtz), Cascade red foxes (Vulpes vulpes

cascadensis Merriam), and other species associated with montane meadows.

Forests

Projected changes in climate are likely to lead to significant changes in forests of 

the North Cascades. As mentioned above, closed-canopy forest may replace portions of the subalpine and alpine zones (see chapter 5). In addition, model simulations project a potential transition from wetter maritime forests to drier temperate 

forests typical of the east slope of the Cascades. However, correlative models (see 

chapter 5) indicate that changes in forest composition may not simply involve a 

westward shifting of east-side species as drier conditions develop. These models 

project a loss in the area of potentially suitable climates for lodgepole pine (Pinus 

contorta var. latifolia Engelm. ex S. Watson) and potentially other pine species 

across much of their current range in the North Cascades.

Model projections for the region also forecast an increase in wildfire area 

burned and wildfire severity (see chapter 5), resulting in more dynamic forest 

landscapes, fewer areas with older trees and mature forest structures, and more 

open areas. Higher temperature has also been linked to higher frequency and 

severity of outbreaks of some insects, such as mountain pine beetle (Dendroctonus 

ponderosae Hopkins). Insect outbreaks may synergistically interact with wildfire 

to produce even more dynamic landscapes and younger forests. These changes will 

benefit species that are well adapted to fire-prone habitat, but will reduce habitat 

Closed-canopy forest 

may replace portions 

of the subalpine and 

alpine zones.
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for species such as the northern spotted owl (Strix occidentalis caurina Merriam) 

and marbled murrelet (Brachyramphus marmoratus Gmelin) that require latesuccessional forests.

Wetlands 

The North Cascades contains thousands of wetlands that differ in size (less than 

10 m2 to more than 10 000 m2) and structure (e.g., wet meadow, riparian, marsh, 

bog, swamp, ephemeral and permanent ponds, lakes), from tiny ephemeral alpine 

ponds to extensive valley complexes. Because wetland hydrology, structure, and 

function respond to changes in temperature and precipitation, wetlands are considered among the most sensitive ecosystems to climate change (Carpenter et al. 

1992, Parry et al. 2007). A diversity of animals such as pond-breeding amphibians, 

invertebrates, predatory birds and waterfowl, mammals, reptiles, and fish rely on 

these wetlands either directly or indirectly. The lack of empirical data and modeling 

resources specific to wetland dynamics makes it difficult to project climate effects 

on wetlands and their wildlife in the North Cascades. However, studies are currently underway to understand climate change effects on wetland dynamics through 

enhanced monitoring and modeling.5

Climate and hydrologic models downscaled for the North Cascades region 

agree on several key projected changes likely to affect wetlands and the wildlife 

that rely on them (Elsner et al. 2010, Mote 2003, Mote and Salathé 2010).6 First, 

temperature increases in all seasons will affect thermal conditions, evaporation 

rates, and evapotranspiration rates that influence wetland depth and hydroperiod 

(timing and duration of inundation). Second, projected changes in the timing and 

form of precipitation (rain vs. snow) (see chapter 4) will alter wetland hydrology. 

Hydrologic changes are complex: shifts in precipitation from snow to rain, in addition to higher precipitation in all seasons except summer, are expected to result in 

earlier soil moisture recharge in winter, earlier filling of riparian overflow wetlands, and earlier high-water levels (see footnote 6). Extreme weather events and 

loss of snowpack may also affect sediment deposition, with implications for wetland 

structure, connectivity, and associated vegetation and substrate characteristics. 

5 Hamlet, A. 2011. Personal communication. Research associate professor, University of 

Washington, Civil and Environmental Engineering, Box 352700, Seattle, WA 98195.

6 Lee. S.-Y.; Hamlet, A.F.; Ryan, M.E. [et al.]. [N.d.]. Modeling wetland response to 

climate change in the Pacific Northwest. On file with: S.-Y. Lee, University of Washington, 

Civil and Environmental Engineering, Box 352700, Seattle, WA 98195.
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Lower snowpack, lower precipitation in summer, earlier soil moisture recession, 

and resulting increases in the frequency of summer drought are projected to cause 

transitions in wetland composition (e.g., from permanent to ephemeral ponds); 

shortened hydroperiods in ephemeral ponds, seeps, and springs; and the complete 

loss of some shallow habitats such as lake edges, wet meadows, and ponds (Poff et 

al. 2002). In contrast, recession of glaciers and snowfields is already creating new 

wetlands at higher elevations. Changes in vegetation and altitudinal treeline are also 

likely to influence wetland hydrology through effects on snow deposition, shading, 

and rates of evapotranspiration. Models generally project higher wetland water 

levels in winter and early spring from elevated soil moisture, more rapid recession 

of water levels in spring, and reduced water levels in summer compared to current 

conditions (see footnote 6). 

Changes in wetland temperature and hydrology will directly affect wildlife 

through habitat and food availability, population dynamics, and life history selection. Wetland inhabitants such as pond-breeding amphibians, freshwater invertebrates, waterfowl, semiaquatic mammals, and fish will be directly affected, with 

cascading effects on the mammals, birds, and reptiles that feed on them. Pondbreeding amphibians are of particular concern because of their reliance on wetlands 

(Bates et al. 2008, Blaustein and Wake 1990, Lawler et al. 2010, Stuart et al. 2004). 

Many studies have demonstrated a correlation between wetland abundance or size, 

and species richness for a variety of taxa (Richter and Azous 2001a, 2001b, 2001c; 

Tiner 2003; Williams 2006). Waterfowl and migratory songbirds use temporary and 

permanent wetlands as food sources and nesting habitat. Semiaquatic or wetlandassociated rodents such as beaver (Castor canadensis Kuhl), mountain beaver 

(Aplodontia rufa Rafinesque), muskrat (Ondatra zibethicus L.), northern boglemmings (Synaptomys borealis Richardson), mesopredators (e.g., striped skunk 

[Mephitis mephitis Schreber], American mink [Neovison vison Schreber], river otter 

[Lontra canadensis Schreber]), and shrews (Sorex spp.) rely heavily on wetlands 

for core habitat. Habitat generalists such as deer, elk, mountain goats (Oreamnos 

americanus de Blainville), and large carnivores rely on wetlands for water sources. 

Although many species will be affected by climate-induced wetland loss, 

some mammals may also contribute to the maintenance of wetlands in a changing 

climate. For example, beavers have been described as “mountain sponges” because 

of their ecosystem engineering traits that create wetlands (Hansen and Hoffman 

2011). Gray wolf (Canis lupus L.) recolonization may also promote maintenance 

and recovery of riparian wetland habitats through their effects on the behavior of 

herbivorous prey (Beschta and Ripple 2012, Naiman and Rogers 1997), with implications for a wide variety of amphibians, birds, invertebrates, and fishes. Changing 

Changes in wetland 

temperature and 

hydrology will affect 

amphibians, freshwater 

invertebrates, 

waterfowl, semiaquatic 

mammals, and fish.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

hydrology and water quality will affect lake- and wetland-reliant native fish species 

at lower elevations such as sockeye salmon (Oncorhynchus nerka Walbaum in 

Artedi), as well as introduced fishes in formerly fishless high-elevation regions.

Across the North Cascades, the cumulative effects of altered wetland hydrology 

on the availability, suitability, connectivity, and resource provisioning of different 

types of wetlands are likely to affect wildlife population persistence and function of 

coexistence mechanisms that influence regional patterns of diversity (Amarasekare 2003, Chesson 2000) (see footnote 5). The probability of drying will vary, as 

does the distribution and composition of wetland habitats and the distribution of 

nonclimatic stressors such as contaminants and introduced fish. Wetland species 

differ considerably in their mobility, so effects of shifting wetland distributions and 

connectivity on metapopulation dynamics will be species specific. 

Riparian Systems

Riparian habitats provide critical resources for many species. Projected changes 

in the timing and volume of streamflow (see chapter 4) have the potential to 

profoundly affect salmon and fish habitat in general, as discussed in chapter 7. In 

addition, increased high flows and flooding have the potential to make some riparian systems more dynamic. Shifting stream channels and the periodic removal of 

riparian vegetation may reduce the suitability of riparian areas as habitat for some 

species. For amphibians that breed in riparian wetlands or streams, higher peak 

flows could produce scouring events that remove eggs and individuals as has been 

observed when flow regimes are altered by dams (Kupferberg et al. 2012). Projected 

lower low flows and more frequent periodic droughts in the dry season in Washington (Mantua et al. 2010) also have the potential to alter riparian vegetation and 

affect riparian wetlands and breeding habitat for amphibians.

Sensitivity of Selected Wildlife Species to Climate 

Change

Scientists and managers assessed the sensitivity of wildlife species of concern using 

the Climate Change Sensitivity Database,7 which summarizes different factors that 

affect species sensitivity to climate change and assigns a relative sensitivity score of 

0 through 100 and a value for the confidence in this score based on input data and 

expert opinion. Workshop participants reviewed and discussed the rankings for

7 Climate Change Sensitivity Database. 2013. A collaboration of the University of Washington, The Nature Conservancy, and state and federal resource agencies in the Pacific 

Northwest. http://climatechangesensitivity.org. (8 November 2013).
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several species of concern for which data had already been entered in the database. 

Participants also used the database to enter information for an additional five 

species of concern: American pika, hoary marmot, yellow-pine chipmunk (Tamias 

amoenus J.A. Allen), Cascade red fox, and western toad. 

Sensitivity differed among the 11 species reviewed (fig. 6.1). Below, we summarize some components of the assessments that led to the rankings in fig. 6.1. Boxes 

6.1 through 6.5 contain additional information on the sensitivity of the five species 

that were assessed during the workshop. Although these are generally assessments 

of sensitivity, we include an evaluation of dispersal ability and barriers to dispersal, 

which could be considered to be components of adaptive capacity. The assessment 

process in the workshop focused on the North Cascades, although in many cases, 

the assessments likely apply to the species throughout their ranges. The assessments 

are based on expert opinion provided in the NCAP workshop and from other expert 

workshops. Additional references and information for the assessments of specific 

species can be found in the Climate Change Sensitivity Database. The 11 species

Text continues on page 198

Figure 6.1—The relative sensitivity to climate change of 11 wildlife species found in the North 

Cascades. Sensitivity scores (black bars) were derived from an index that integrates information 

about physiological tolerances, habitat use, interspecific interactions, dispersal abilities, nonclimatic 

stressors, and other stressors. Information on these specific factors was provided by experts in 

the North Cascadia Adaptation Partnership workshop and other expert workshops. The gray bars 

represent confidence of the experts in their assessment of sensitivity. Higher bars represent higher 

levels of confidence.
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Box 6.1—Sensitivity assessment for the American pika

For the American pika, the overall sensitivity score was 63 (scale of 1 through 100) 

and confidence in this score by experts populating the Climate Change Sensitivity 

Database* was 80 (scale of 1 through 100). Sensitivity and confidence by sensitivity 

factor are shown in the following table.

Confidence

Sensitivity factor Sensitivity in sensitivity

Generalist/specialist 7 5

Physiology 7 5

Life history 3 5

Sensitive habitats 7 4

Dispersal distance 5 5

Dispersal barriers 4 5

Disturbance regimes 2 3

Ecology 3 4

Nonclimatic 3 3

Other 1 3

Overall 63 80

Below we describe the expert information that contributed to the score for each factor; additional information can be found in the database. 

Generalist/specialist: Although some references indicate specific food requirements, 

the pika is primarily a generalist in terms of forage requirements. However, it does 

require high-elevation rock fields that are in proximity to meadows for foraging, making it a habitat specialist.

Physiology: It needs a moderate amount of snow to provide insulation from cold temperatures in the winter. Some colonies may be sensitive to thermal stress. 

Life history: It can breed after one year and reproduce twice a year with litters of two 

to six kits.

Sensitive habitats: Generally it relies on subalpine and alpine habitats and montane 

meadows. These habitats are likely to be highly sensitive to climate change. However, 

some populations are found at lower elevations around lava tubes, freeway shoulders, 

and lava beds.

Dispersal distance: Its maximum annual dispersal is estimated to be 20 km for juveniles, but is usually less than 10 km.

Dispersal barriers: Roads; agriculture; residential, rural, and urban development; 

rivers; arid lands; and lower elevations act as dispersal barriers.

Disturbance regimes: The pika is not tightly linked to particular disturbance regimes, although changes in the frequency of drought and the intensity of wind may 

affect food resources and dehydration.

Ecology: Changes in temperature and precipitation may affect forage.

Nonclimatic: Habitat loss and degradation have the potential to exacerbate the 

impacts of climate change.

Other: A new predator could cause significant impacts as could the emergence of 

nonanalog communities and changes in the plant community.

* http://climatechangesensitivity.org
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Box 6.2—Sensitivity assessment for the hoary marmot

For the hoary marmot, the overall sensitivity score was 64 (scale of 1 through 100) 

and confidence in this score by experts populating the Climate Change Sensitivity 

Database* was 60 (scale of 1 through 100). Sensitivity and confidence by sensitivity 

factor are shown in the following table.

Confidence

Sensitivity factor Sensitivity in sensitivity

Generalist/specialist 5 4

Physiology 4 2

Life history 5 4

Sensitive habitats 7 5

Dispersal distance 5 3

Dispersal barriers 2 3

Disturbance regimes 5 4

Ecology 4 3

Nonclimatic 3 4

Overall 64 60

Below we describe the expert information that contributed to the score for each factor; 

additional information can be found in the database. 

Generalist/specialist: The hoary marmot is a habitat specialist that requires subalpine 

meadows for habitat, but it is a generalist with respect to forage.

Physiology: It may be moderately physiologically sensitive to changes in precipitation 

and temperature, but little is known. 

Life history: It breeds after three years, and then breeds once per year having between two and five young in each litter.

Sensitive habitats: It depends on subalpine meadows, which are sensitive to climate 

change.

Dispersal distance: Its maximum annual dispersal is estimated to be between 5 

and 25 km. 

Dispersal barriers: Rivers and geologic features act as barriers to dispersal. 

Disturbance regimes: It is not linked to particular disturbance regimes, although 

changes in snowpack will affect the persistence of subalpine meadows (as noted above 

under sensitive habitats).

Ecology: Predation pressure may increase for hoary marmots if coyotes (Canis 

latrans Say) move up in elevation as the duration or extent of snowpack decreases. 

Hibernation patterns may be altered by changing snowpack duration, earlier snowmelt, longer drier summers, and changes in forage species.

Nonclimatic: Habitat loss and degradation, recreational killing, and resource development and mining all have the potential to exacerbate the impacts of climate change on 

the marmot.

* http://climatechangesensitivity.org
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Box 6.3—Sensitivity assessment for the yellow-pine 

chipmunk

For the yellow-pine chipmunk, the overall sensitivity score was 55 (scale of 1 

through 100) and confidence in this score by experts populating the Climate Change 

Sensitivity Database* was 60 (scale of 1 through 100). Sensitivity and confidence by 

sensitivity factor are shown in the following table.

Confidence

Sensitivity factor Sensitivity in sensitivity

Generalist/specialist 3 4

Physiology 2 3

Life history 4 5

Sensitive habitats 7 5

Dispersal distance 6 3

Dispersal barriers 5 4

Disturbance regimes 4 5

Ecology 3 4

Nonclimatic 2 3

Overall 55 60

Below we describe the expert information that contributed to the score for each factor; additional information can be found in the database. 

Generalist/specialist: The yellow-pine chipmunk is a generalist with respect to food 

and habitat.

Physiology: It is not likely to be physiologically sensitive to changes in temperature 

or precipitation. 

Life history: It breeds after one year and breeds once per year having between one 

and three young in each litter.

Sensitive habitats: It depends on open ponderosa pine forests that will be affected by 

changes in moisture and disturbance regimes. 

Dispersal distance: Its maximum annual dispersal is estimated to be between 1 and 

5 km. 

Dispersal barriers: Roads, agriculture, industrial and urban development, rivers, 

arid lands, mountains, and geologic features can act as barriers to dispersal.

Disturbance regimes: Increased frequency of wind events could lead to increased 

blow down, which would create more favorable habitats. Increased high-severity fire 

could negatively affect habitat quality. Droughts could affect truffle abundance.

Ecology: Climate change could exacerbate competition with other chipmunk species.

Nonclimatic: Habitat loss and degradation and high-severity fire are factors that 

could exacerbate the impacts of climate change and interact with climate change.

* http://climatechangesensitivity.org
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Box 6.4—Sensitivity assessment for the Cascade 

red fox

For the Cascade red fox, the overall sensitivity score was 66 (scale of 1 through 100) 

and confidence in this score by experts populating the Climate Change Sensitivity 

Database* was 60 (scale of 1 through 100). Sensitivity and confidence by sensitivity 

factor are shown in the following table.

Confidence

Sensitivity factor Sensitivity in sensitivity

Generalist/specialist 2 3

Physiology 2 1

Life history 5 4

Sensitive habitats 7 5

Dispersal distance 4 3

Dispersal barriers 5 3

Disturbance regimes 4 3

Ecology 5 4

Nonclimatic 5 3

Other 5 3

Overall 66 60

Below we describe the expert information that contributed to the score for each factor; 

additional information can be found in the database. 

Generalist/specialist: The Cascade red fox is a generalist, although it depends upon 

alpine and subalpine habitats and the prey species associated with them (see sensitive 

habitats below).

Physiology: It is not likely to be physiologically sensitive to changes in temperature or 

precipitation, although there is little information on this assumption. 

Life history: It breeds after one year, and breeds once per year having up to four 

young in each litter.

Sensitive habitats: It depends on alpine and subalpine meadows that will be sensitive 

to climate change.

Dispersal distance: Its maximum annual dispersal is estimated to be between 25 and 

50 km.

Dispersal barriers: Low-elevation forest may act as dispersal barriers because the 

species is not commonly found below 900 m.

Disturbance regimes: Fire and drought have the potential to affect alpine and subalpine habitats and prey species.

Ecology: Temperature and precipitation have the potential to affect prey species abundance.

Nonclimatic: Invasive species, competition, and direct human interactions will likely 

increase sensitivity to climate change. Additional concerns include already low populations and the potential expansion of coyotes (Canis latrans Say) and introduced red 

fox (Vulpes vulpes L.) to higher elevations.

Other: Genetic ramifications of small population sizes are a concern; research on this 

topic is ongoing.

* http://climatechangesensitivity.org
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Box 6.5—Sensitivity assessment for the western toad

For the western toad, the overall sensitivity score was 91 (scale of 1 through 100) 

and confidence in this score by experts populating the Climate Change Sensitivity 

Database* was 88 (scale of 1 through 100). Sensitivity and confidence by sensitivity 

factor are shown in the following table.

Confidence

Sensitivity factor Sensitivity in sensitivity

Generalist/specialist 4 4

Physiology 6 5

Life history 2 5

Sensitive habitats 7 5

Dispersal distance 6 4

Dispersal barriers 5 4

Disturbance regimes 7 5

Ecology 7 5

Nonclimatic 7 5

Other 7 5

Overall 92 88

Below we describe the expert information that contributed to the score for each factor; additional information can be found in the database. 

Generalist/specialist: The western toad is a specialist because it requires shallow 

breeding habitat.

Physiology: The western toad, like many amphibians, is physiologically sensitive to 

changes in temperature, precipitation, pH, and dissolved carbon dioxide.

Life history: Although it breeds only after 3 to 5 years and only once per year, it 

produces about 12,000 eggs per clutch.

Sensitive habitats: It relies on seasonal streams, shallow wetlands, vernal pools, 

seeps and springs, and alpine and subalpine areas.

Dispersal distance: Its maximum annual dispersal is estimated to be between 1 and 

5 km. 

Dispersal barriers: Roads, agriculture, suburban and rural residential development, 

clearcuts, rivers, dams, mountains, and geologic features act as barriers. Trails may be 

barriers to juveniles.

Disturbance regimes: It is likely to be highly sensitive to changes in flooding, disease dynamics, drought, and potentially fire.

Ecology: Changes in temperature, precipitation, and pH have the potential to affect 

a wide array of factors including hydroperiod, food resources, competition, predatorprey relationships, and disease dynamics.

Nonclimatic: Invasive species, direct human conflict (recreational uses and roads), 

pollution, habitat loss and degradation, and disease will likely increase sensitivity to 

climate change. 

Other: In general, this species is rapidly declining across its range. Such a decline is 

likely to make the species more susceptible to climate change.

* http://climatechangesensitivity.org
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reviewed and assessed during the workshop are not necessarily the most sensitive 

species in the North Cascades. Many other species are likely to be as sensitive or 

more sensitive to climate change; similar assessments of more species can be found 

in the Climate Change Sensitivity Database. 

The rankings provided by the Climate Change Sensitivity Database provide one 

indication of sensitivity and are a tool for comparing sensitivity among species, but 

the specific aspects of a species’ life history and habitat that make it sensitive to 

climate change provide more information than rankings alone. Below we summarize some aspects that the species and their habitats contribute to the ranking. This 

information can inform adaptation actions, as well as focus additional monitoring 

and research to better understand species’ responses to climate change. 

American pika— 

Physiological factors and habitat requirements make the American pika (fig. 6.2) 

very sensitive to climate change. Its inability to tolerate high temperatures and dependence on a moderate amount of snow cover limit its distribution to higher elevations. Although it does not specialize on particular grasses or forbs, it has relatively 

specific habitat requirements because it needs rock fields in proximity to montane 

meadows. Montane meadows themselves may be sensitive to higher temperature 

and lower snowpack.

Figure 6.2—The American pika is a small 

lagomorph that inhabits boulder fields at higher 

elevations. Pikas are particularly sensitive to 

warm temperatures in the summer and to cold 

temperatures in the winter. 

Hoary marmot— 

The hoary marmot (fig. 6.3) is likely to be very sensitive to climate change. Similar 

to the pika, the hoary marmot depends on higher elevation habitats, particularly 

alpine and subalpine meadows, which may decline in area because of tree encroachment. Although the marmot does not share the physiological sensitivities of the 

pika, it will be sensitive to the loss of alpine and subalpine vegetation and reduced 

area of montane meadows.

The hoary marmot will 

be sensitive to the loss 

of alpine and subalpine 

vegetation and reduced 

area of montane 

meadows.
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Cascade red fox— 

The Cascade red fox is likely to be very sensitive to climate change because of its 

dependence on alpine and subalpine areas and high-elevation meadows. In addition, 

the fox may be limited in its ability to disperse to other high-elevation areas and 

will likely be sensitive to climate-driven changes in prey abundance. 

Yellow-pine chipmunk— 

The yellow-pine chipmunk (fig. 6.4) is likely to be moderately sensitive to climate 

change. In the North Cascades, the chipmunk is a habitat specialist, inhabiting only 

open ponderosa pine (Pinus ponderosa Douglas ex P. Lawson & C. Lawson) forests. 

An increase in fire frequency in these forests may reduce habitat available for the 

chipmunk, and droughts have the potential to reduce food abundance. Dispersal for 

the chipmunk is relatively limited, particularly because of barriers such as roads, 

which increases its sensitivity.

Figure 6.3—The hoary marmot is a large ground 

squirrel that lives at higher elevations. Marmots feed 

on grasses and forbs and live near treeline. Eemeli Haverinen

Figure 6.4—The yellow-pine chipmunk is a small 

rodent that inhabits drier forests of the Pacific 

Northwest. Damean Kuhn
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Western toad— 

The western toad (fig. 6.5) is likely to be sensitive to climate change because the 

species life history depends on intermittent and permanent habitats such as streams, 

seeps, wetlands, vernal pools, ponds, and lakes (Bull 2009) that are sensitive to 

changes in precipitation and hydrologic regimes. Western toad survival is also affected by disease such as chytridiomycosis, avian predation, desiccation, habitat 

alteration, and fire (Bull 2009, Guscio et al. 2007). Western toad survival is highly 

correlated with having adequate water sources for reproduction, dispersal, and rehydration (Bull 2009). Desiccation and water loss in streams and pools along dispersal 

routes can limit dispersal and create barriers to movement (Bull 2009).

Figure 6.5—The western toad is a large toad with 

a range that extends from Alaska to California and 

east to Utah and Colorado. Walter Siegmund

Northern spotted owl—

The northern spotted owl (fig. 6.6) is likely to be very sensitive to climate change. 

First, the owl is a specialist with respect to both habitat and food resources. It will 

be sensitive to climate-driven changes in the distribution and abundance of prey 

species, as well as climate-driven changes in the prevalence of late-successional 

forest area and structural components. Second, the species is currently threatened 

by reduced habitat and interactions with the barred owl. Bioclimatic envelope models indicate that as climate changes in the spotted owl’s range, higher elevation latesuccessional reserves may become particularly important for preserving the species 

(Carroll 2010).

Western toad survival 

requires adequate 

water for reproduction, 

dispersal, and 

rehydration.
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Marbled murrelet— 

A combination of factors will likely make the marbled murrelet (fig. 6.7) very sensitive to climate change. The marbled murrelet requires specific habitat structures in 

late-successional forests for nesting and is already threatened by habitat loss. It is 

a long-lived, slowly reproducing species. Thus, although it may be able to survive 

several years of climatic conditions that are not favorable, the population will be 

slow to recover from extreme conditions or events, and the likelihood of adapting to 

rapidly changing climatic conditions will be relatively low.

Figure 6.6—The northern spotted owl inhabits late-successional 

forests of the Pacific Northwest. Its population has declined in 

response to habitat loss over the last century. In addition to loss of 

habitat, the northern spotted owl is also threatened by competition 

from the barred owl, whose range has expanded to overlap with that 

of the northern spotted owl. U.S. Geological Survey and Patrick Kolar

Figure 6.7—The marbled murrelet is a member of the auk 

family that forages at sea and nests in old trees in coastal 

forests. The species has declined as a result of terrestrial habitat 

reduction during the 20th century. Gus Van Vliet

Clark’s nutcracker— 

Clark’s nutcracker (Nucifraga columbiana Wilson) (fig. 6.8) is likely to be moderately sensitive to climate change. Although it depends on conifers with large seeds 

for food, its habitat contains a variety of species. It uses subalpine zones for feeding and nesting, but also feeds and nests in lower elevation forests. Thus, climate 

change will likely affect the nutcracker, but the species will not be as sensitive to 

changes in forest structure and composition as other species.
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White-tailed ptarmigan— 

The white-tailed ptarmigan (Lagopus leucura Richardson) (fig. 6.9) depends on 

alpine and subalpine habitats, so it is likely to be very sensitive to climate change. 

Ptarmigans are also more limited in their dispersal ability than other birds and thus 

may have trouble tracking climatic changes that require movements between distant 

mountain ranges.

Figure 6.8—The Clark’s nutcracker is a corvid 

that feeds primarily on large pine seeds. Its use of 

whitebark pine (Pinus albicaulis Engelm.) seeds 

may make this species sensitive to climate change 

because that resource is decreasing as a result of 

whitebark pine mortality from white pine blister 

rust (Cronartium ribicola A. Dietr.) and mountain 

pine beetle outbreaks at higher elevations. U.S. Fish and Wildlife Service, and Dave Menke

Figure 6.9—The white-tailed ptarmigan is a 

small grouse species that inhabits alpine and 

subalpine habitat. Its dependence on cool, 

high-elevation habitats makes this species 

particularly sensitive to a changing climate. John Hill

Elk— 

Elk (fig. 6.10) are likely to be relatively insensitive to climate change. The species 

could be affected by changes in climate, but elk are habitat and forage generalists, 

so they have more potential food sources even if vegetation distribution and abundance change. They can move long distances and tolerate a large range of climatic 

conditions, which also decreases sensitivity.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Northern red-legged frog— 

The northern red-legged frog (fig. 6.11) is well adapted to the cool and wet climate 

of the western Pacific Northwest (PNW). This species inhabits and requires aquatic 

habitats with stable water levels (such as extensive wetlands, shallow ponds, and 

slow-moving streams with marshy edges) for the successful completion of its life 

history (Leonard and McAllister 2005). This species could be sensitive to climate 

change because of its dependence on these habits that are sensitive to changes in 

precipitation and hydrologic regimes. Current threats to survival include wetland 

destruction, habitat degradation and fragmentation, urbanization and residential 

development, drought, and the introduction of exotic fish and bullfrogs. Climate 

change has been hypothesized as a potential threat to the survival of the red-legged 

frog, but present declines are more consistent with other threats (Davidson et 

al. 2001). Like other amphibians, the northern red-legged frog may experience a 

change in susceptibility or exposure to diseases such as the chytrid fungus, which is 

sensitive to temperature (Berger et al. 2004). Movement of the species may be further restricted if changes in climate lead to drier forest conditions. 

Figure 6.10—Elk are one of the largest land mammals in 

North America. They use a diversity of habitats including 

low-elevation pastures and high-elevation meadows and 

forests. 

Figure 6.11—The northern red-legged frog inhabits 

the coastal region from California north to British 

Columbia. Walter Siegmund
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Wildlife Management in National Forests and National 

Parks in the North Cascades

Planning and Regulation

Wildlife management in the national forests and national parks in the NCAP 

reflects both “fine filter” and “coarse filter” approaches. Fine filter approaches 

focus on managing individual species whereas coarse filter approaches focus 

on managing habitat for multiple species by maintaining ecosystem processes 

and functions. Direction and objectives for managing wildlife and habitat on the 

national parks and forests are based on a mix of national, regional, and unit-level 

policies, plans, and programs. Wildlife management practices include (1) managing threatened, endangered, sensitive, and iconic species; (2) monitoring wildlife 

populations and habitat; and (3) protecting and restoring wildlife habitat. 

Direction and objectives for managing wildlife on the Mount Baker-Snoqualmie 

(MBSNF) and Okanogan-Wenatchee (OWNF) National Forests are based on 

regional plans and strategies, as well as forest-specific land and resource management plans (i.e., forest plans). In 1994, the forest plans of both national forests were 

amended by the Northwest Forest Plan (NWFP) (USDA and USDI 1994). Motivated 

by litigation associated with the listing of the northern spotted owl as a threatened 

species under the Endangered Species Act (ESA) of 1973 (ESA 1973), the NWFP 

provides direction for managing wildlife habitat and surveying critical species 

within the range of the northern spotted owl, which includes all of the MBSNF 

and the OWNF north and west of the Chewuch River. The objective of the plan is 

to provide for the long-term sustainability of forests, including the wildlife species 

that inhabit them, by establishing late-successional reserves and standards and 

guidelines for protection and monitoring of late-successional habitat and dependent 

wildlife species. Despite its emphasis on long-term sustainability, the NWFP did 

not consider potential effects of climate change on wildlife species or climatedriven changes in disturbance regimes on habitat and late-successional reserves 

(Mawdsley et al. 2009). 

Regional direction for wildlife management in the area of OWNF not covered 

by the NWFP is provided by the East-Side Screens (the decision notice for the 

revised continuation of interim management direction establishing riparian, ecosystem and wildlife standards for timber sales). Similar to the NWFP, the East-Side 

Screens directs the OWNF to manage ecosystem processes and functions, but it 

emphasizes the natural range of variability in ecosystem structure, rather than a 

system of reserves. Management objectives in the East-Side Screens do not consider 

climate change and assume static disturbance regimes. 
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The USDA FS Pacific Northwest Region provides direction to both national forests for managing wildlife habitat with the Terrestrial Restoration and Conservation 

Strategy (TRACS) (USDA FS 2012a). This strategy identifies regional priorities for 

species, habitats, and watersheds with the greatest need for conservation, restoration, and habitat enhancement. Conservation protects and maintains a healthy functioning wildlife habitat, restoration improves degraded habitats, and enhancement 

augments habitat components for featured species. Included in TRACS is a list 

of species and habitats that are threatened by climate change, and climate change 

(drought and extreme temperatures) is one factor in prioritizing a species or habitat. 

The strategy encourages collaboration and integration with external partners to 

manage wildlife across administrative boundaries and responding to climate change 

impacts is highlighted as an opportunity for collaboration. 

In addition to these regional plans, specific objectives and direction for wildlife 

management are given in forest plans. The OWNF forest plan, currently under 

revision, seeks to increase the consistency of objectives in forest-level planning 

with that of the regional plans. The primary objective of wildlife management in 

OWNF is to recover and maintain viable populations of native wildlife species, 

but this objective is balanced with maintaining access for recreation, fire management, and forest restoration. The revised OWNF forest plan modifies the previous 

management focus on specific wildlife species with an approach that focuses more 

on managing ecosystems processes to create diverse landscapes, a key factor in 

enhancing resiliency of wildlife and vegetation to climate change. 

The primary objective for wildlife management at MBSNF is to maintain and 

restore wildlife resources to ensure the use of these resources and the maximum 

benefit for the forest, its other resources, and associated communities. Restoration 

actions for wildlife habitat are prioritized first for species with the highest political 

and ecological significance and second for species for which actions will result in 

substantial improvements to habitat and populations. 

Direction and objectives for managing wildlife in the national parks are given 

by the NPS Organic Act (NPS 1916), management policies (USDI NPS 2006b), 

and individual park foundation statements and general management plans. The 

NPS management policies direct park managers to maintain the natural abundance, 

diversity, and genetic and ecological integrity of native wildlife species. Generally, 

the NPS relies on natural processes to maintain ecosystem functions and components, but managers can intervene with individuals or populations of native species when intervention will not cause unacceptable effects on the species or other 

components and processes of the ecosystem. Furthermore, managers can intervene 

only to (1) protect unnaturally low or high population levels, (2) protect cultural 

The Forest Service 

has identified 

regional priorities for 

species, habitats, and 

watersheds.
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resources, (3) accommodate development in areas designated for development, (4) 

protect human health and safety, or (5) protect property when it is not possible to 

change the pattern of human activities. Shifts in species distributions driven by 

climate change may challenge policy definitions of native species. Furthermore, 

these criteria by which managers can intervene to manage populations suggest that 

attributing climate change to human causes may be necessary to justify intervention to maintain current native species that are threatened by climate change.

Management of Wildlife Species in the North Cascades

All NCAP units are home to state or federally listed (sensitive, threatened, and 

endangered) or candidate species, and managers are required to collaborate with 

the USFWS and WDFW and participate in species recovery plans. The ESA (1973) 

requires all federal agencies to conserve threatened and endangered species and 

prohibits agencies from authorizing, funding, or carrying out any action that would 

harm a listed species or its habitat. 

The MBSNF is home to 3 threatened species and 1 endangered species, as well 

as an additional 15 sensitive species, species of concern, or management indicator species, which include large and small mammals, birds, and amphibians. The 

national forest participates in recovery plans, and management for these species 

focuses on monitoring populations and increasing late-successional habitat under 

the NWFP. 

The OWNF participates in recovery plans for several sensitive and listed 

species including grizzly bear, Canada lynx (Lynx canadensis Kerr), gray wolf, 

wolverine, fisher (Martes pennanti Erxleben), and the northern spotted owl. Management goals for these species differ but generally focus on reducing negative 

impacts of roads on habitat quality and connectivity, protecting critical habitats, and 

restoring late-successional forest conditions and structural components (e.g., large, 

old trees and large snags). The OWNF participates in the grizzly bear recovery 

plan (Servheen 1997), which has a goal of “no net loss” of high-quality grizzly bear 

habitat. The recovery plan limits construction of new roads and trails and seeks to 

reduce bear-human interactions. The forest plan for OWNF includes provisions to 

increase habitat for grizzly bears while enhancing safety for humans with vegetation treatments and management of human access, road densities, and recreation 

facilities. Canada lynx habitat is managed in accordance with the Lynx Conservation Assessment and Strategy, an interagency science-based assessment (Ruediger 

et al. 2000). Managers protect den sites for the gray wolf. Management of wolverine 

and fisher, which are listed as sensitive species for the USDA FS Pacific Northwest 

Region and candidate species for listing under the ESA (1973), will be based on the 

regional assessment of habitat needs for landscape connectivity. 
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Climate change provides a new context through which to assess the feasibility 

of goals and objectives of species-specific recovery plans, given potential effects on 

populations and habitats. Management of the northern spotted owl on the OWNF 

provides an example of the consequences of considering only static ecosystems in 

recovery plans. The OWNF manages for northern spotted owl by restoring the historical range of variability of late-successional habitat, but considerable habitat has 

been lost to extensive, high-severity wildfire. This loss of habitat promoted a shift 

towards managing for future range of variability. A revised goal of forest restoration is to determine the extent and arrangement of late-successional habitat that is 

sustainable now, but that will also be resilient to climate change and sustainable in a 

warmer climate with more fire (USDA FS 2012b). 

The NPS management policies (USDI NPS 2006b) direct managers to participate in the recovery planning process; undertake active management programs 

to inventory, monitor, restore, and maintain habitat for listed species; control 

detrimental nonnative species; manage detrimental visitor access; and reestablish 

extirpated populations as necessary. The national parks are required to manage 

designated critical habitat, essential habitat, and recovery areas to maintain and 

enhance their value for recovery of threatened and endangered species. 

Wildlife ecology programs of the NPS include compliance and inventory, 

monitoring, research, and protection of threatened and endangered species. Mount 

Rainier National Park is home to 163 bird species, 55 mammals, 5 reptiles, and 14 

amphibians, 2 of which (northern spotted owl and marbled murrelet) are federally 

listed threatened and endangered species. Another 12 federal species of concern and 

state-listed species occur or are likely to occur in the park. North Cascades National 

Park Complex (NOCA) is home to 210 bird species, 78 mammals, 10 reptiles, and 

12 amphibians. Of these species, 7 are federally listed species, 2 are federal candidates, and 16 are state listed. Wildlife managers inventory distributions of listed 

species and comply with National Environmental Policy Act requirements to protect 

species from all park activities associated with managing roads, trails, and facilities 

(NEPA 1969). Both parks are potential sites for an experimental USFWS program 

to remove barred owls (Strix varia Barton) with the goals of evaluating linkages 

between northern spotted owl and barred owl populations and investigating the 

feasibility of barred owl removal as a conservation tool. Mount Rainier National 

Park includes 10 000 ha of suitable nesting habitat for the marbled murrelet, and 

management of the species includes radar surveys of populations. The park also has 

one of three populations of the Cascade red fox, which is a candidate species for 

state listing. 
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A primary focus of wildlife management in MORA and NOCA is to reduce 

human impacts to wildlife from management and recreational activities. Managers 

seek to reduce impacts associated with vehicle collisions and human feeding and 

habituation. Increased visitation associated with warmer temperatures and a longer 

snow-free season could increase human-wildlife interactions, although increased 

visitation would likely be concentrated in areas that already have high use. Wildlife 

managers minimize and mitigate impacts of construction; all newly constructed 

or rehabilitated facilities are built to avoid critical habitat corridors, nesting, and 

denning sites, and construction activities are timed to avoid sensitive periods of 

wildlife activity. These considerations will become more important with increases 

in construction associated with more flood and landslide damage in a changing 

climate (see chapter 4). 

Management of Wildlife Habitat in the North Cascades

In addition to fine filter approaches focused on listed species, wildlife managers 

on the national forests and national parks in NCAP protect and maintain ecosystem 

functions and processes associated with diverse, high-quality habitat for native 

species. Management for wildlife habitat on the MBSNF focuses on protecting and 

restoring late-successional habitat in areas outside of wilderness and reserves designated by the NWFP. Habitat management includes commercial and precommercial 

thinning of 400 to 800 ha per year with the goal of accelerating development of 

late-successional habitat for old-growth-dependent species. 

Management for wildlife habitat in the revised OWNF Land and Resource 

Management Plan (USDA FS 2011) and Restoration Strategy (USDA FS 2012b) 

includes objectives for restoring and improving habitat, habitat effectiveness, 

and core areas on approximately 100 000 ha over the next 15 years. In addition 

to restoration projects designed for specific species, restoration projects will be 

designed for groups of species with similar habitat requirements. The restoration 

strategy shifts management from a focus on commodity production to a focus on 

ecosystem restoration and resiliency. It focuses on restoring wildlife habitat in dry 

fire-adapted forests that have been affected by selective harvesting and fire exclusion, and it highlights the importance of maintaining forest structures for wildlife 

such as snags, down woody debris, and large old trees. Currently, the extent of 

late-successional habitat is below the natural range of variability in several forest 

types in OWNF because of past management and recent severe fires. Restoration 

of large trees, snags, and late-successional forest structure will increase the area of 

late-successional habitat. The forest plan and restoration strategy also emphasize 

the need for habitat connectivity given the increasing fragmentation of habitat surrounding the OWNF.
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National Park Service managers focus on protecting and mitigating impacts 

to ecological processes to preserve populations of native species. Thus management for wildlife habitat focuses on actions by park staff and visitors rather than 

habitat modifications. Examples of actions to mitigate impacts on wildlife habitat 

include (1) restricting helicopter use by season or time of day, (2) restricting trail 

use because of wildlife use, and (3) prescribing trail density and recreation activities (such as distances between cooking and camping areas) based on impacts to 

wildlife habitat. Park managers also work cooperatively with the USDA FS and 

other adjacent land management agencies to protect ecosystem habitat and wildlife 

corridors. 

Monitoring Wildlife and Habitat

Monitoring as part of adaptive management is a key component of effective restoration and management of wildlife habitat identified by USDA FS policies. To inform 

their adaptive management program, wildlife managers on the OWNF monitor 

habitat and wildlife population dynamics, including snag abundance and avian 

and small mammal response to vegetation treatments. Wildlife managers on the 

MBSNF monitor populations of northern spotted owls, mountain goats, and wintering bald eagles (Haliaeetus leucocephalus L.) in the Skagit River valley. Wildlife 

managers on both forests survey and manage critical species as required by the 

NWFP. Currently, wildlife monitoring on the national forests does not emphasize 

climate change, but monitoring and adaptive management will become increasingly 

important for detecting effects of climate change on wildlife. 

Inventory and monitoring of wildlife species and habitats in MORA and 

NOCA is conducted at both the park level and at the regional level as part of the 

North Cascades and Coast Network (NCCN) inventory and monitoring program. 

Wildlife monitoring by NCCN includes long-term surveys to determine trends in 

land bird, bat, and forest carnivore populations. Elk are a biologically and politically 

important species at MORA, so NCCN monitors elk populations there. The parklevel inventory and monitoring program in MORA monitors northern spotted owl 

demography, human impacts to the Cascade fox population, and distributions of 

butterflies, American pika, amphibians, and harlequin duck (Histrionicus histrionicus L.). The park-level inventory and monitoring program at NOCA periodically 

monitors marmots and annually monitors mountain goats, bald eagles, peregrine 

falcons (Falco peregrinus Tunstall), and butterflies. Wildlife research at NOCA 

currently includes studies of the western gray squirrel (Sciurus griseus Ord), 

mountain goat, American pika, grizzly bear, and wolverine. Both parks are under 

consideration for the reintroduction of fishers.

Monitoring and 

adaptive management 

will be important for 

detecting effects of 

climate change on 

wildlife.
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Adapting Management of Wildlife and Wildlife Habitat in 

a Changing Climate

During the NCAP wildlife workshop, participants collaboratively identified adaptation options for managing wildlife and wildlife habitat given projected effects of 

climate change. Participants reviewed basic principles of adaptation and recommendations for adapting management of wildlife and biodiversity to a changing 

climate. In their review of adaptation literature, Heller and Zavaleta (2009) found 

that research on climate change adaptation has been mostly conceptual and that 70 

percent of recommendations in the scientific literature can be classified as general 

principles rather than specific actionable tactics. Furthermore, because of the difficulties associated with developing experiments to test the effectiveness of adaptation actions, many recommendations are based on general ecological principles 

rather than specific research or empirical data (Heller and Zavaleta 2009). 

The adaptation strategies and tactics for wildlife management identified in the 

NCAP workshop reflect this current state of the science, but participants attempted 

to increase specificity by identifying on-the-ground actions (i.e., tactics) in addition 

to general strategies. Adaptation strategies and tactics reflect a mix of fine filter 

approaches aimed at management of individual species and coarse filter approaches 

aimed at management of habitats and ecosystem processes, reflecting the mixed 

model with which wildlife is managed in the region. The adaptation strategies 

are also a mix of resistance, resilience, and response strategies (see chapter 1 for 

definitions); the relevance of each approach will likely change with time as climate 

change effects are realized. 

Scientists and managers identified adaptation strategies and tactics for five 

habitats and associated species: (1) low-elevation maritime forests on the western 

slopes of the Cascade Range, (2) low-elevation dry forests on the eastern slopes of 

the Cascade Range, (3) riparian forests, (4) subalpine and alpine ecosystems, and 

(5) wetlands. In several cases, adaptation strategies identified for management of 

wildlife habitat are similar or complementary to adaptation strategies identified for 

vegetation management (see chapter 5), indicating the importance of multidisciplinary coordination. The similarities of these strategies provide an opportunity to 

identify “win-win” adaptation strategies for both wildlife and vegetation (Littell et 

al. 2012).
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Adaptation Options for Low-Elevation Maritime Forests on the 

Western Slopes of the Cascade Range 

Low-elevation forests on the western slopes of the Cascade Range were considered 

by managers to be the least sensitive of the five habitats, but participants identified 

adaptation strategies and tactics to minimize adverse effects of shifts in species 

distributions and increases in fire and insect disturbances (table 6.1). Ranges of 

native tree species are likely to shift (Rogers et al. 2011), but forest managers may 

be able to allow these shifts if the habitat structure and composition continue to 

support viable populations of threatened and endangered species. However, more 

wildfire and insect outbreaks will likely decrease the area of late-successional 

forest habitat and increase habitat fragmentation for species that depend on large 

areas of late-successional forests. This will challenge forest management under the 

NWFP, particularly in MBSNF, where management focuses on protecting a static 

system of late-successional reserves and large areas of contiguous habitat. 

In the long term, increasing the resilience of low-elevation maritime forests to 

fire and insects may be necessary to prevent the loss of critical late-successional 

habitat (Dale et al. 2001, Millar et al. 2007). At large spatial scales, increasing the 

diversity of forest structure and age classes can decrease susceptibility and spread 

of severe and extensive disturbances, thus increasing resilience (Hessburg et al. 

2005, Spies et al. 2006). At smaller spatial scales, resilience of individual stands 

can be increased with vegetation treatments designed to increase tree vigor, accelerate development of late-successional structure, increase species diversity, and 

protect critical habitat structures such as nest trees and snags (Halofsky et al. 2011). 

These treatments can be prioritized in areas projected to have the largest increases 

in drought stress. Monitoring of insects can detect infestations before outbreaks 

become extensive, potentially creating triggers for management action to increase 

forest resilience to insect outbreaks. These tactics are consistent with current management of the matrix, adaptive management areas, and developed zones of national 

forests, and thus do not represent significant departures from current management. 

However, managers may consider adjusting priority locations for treatment or 

prescriptions based on projected changes in species distributions and drought stress. 

In the long-term, climate change may motivate managers to consider changes 

in management that are more significant departures from current practices. For 

example, managing vegetation in reserves and increasing the use of prescribed 

fire in ecosystems not historically adapted to fire may increase resilience to more 

frequent disturbances. This would require a review of the current reserve system 

and restrictions on management in reserves under the NWFP to increase management options (Spies et al. 2006). The NWFP and late-successional reserves were 

More wildfire and 

insect outbreaks will 

decrease the area of 

late-successional forest 

and increase habitat 

fragmentation for some 

species.
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general technical report pnw-gtr-892 Table 6.1—Climate change sensitivities of west-side maritime forest habitat; adaptation strategies and tactics to reduce impacts Adaptation tactics Opportunities for implementation Barriers to implementation Information needs Sensitivity: Increasing loss of late-successional forest habitat and connectivity with more insect outbreaks and fire. Strategy: Increase resilience of late-successional habitat. • Increase landscape biodiversity and heteroge- neity by modifying species composition • Increase diversity of age classes and restore patch mosaic • Accelerate development of additional late- successional habitat in matrix • Increase protection of critical habitat structures (e.g., snags and nest trees)

• Consider policy changes to allow more management and adaptive management in latesuccessional reserves• Consider more use of prescribed fire • Increase monitoring of insects to anticipate and 

prevent outbreaks

• Allow shifts in native species ranges

Short-term impacts of vegetation treatments on sensitive speciesNorthwest Forest Plan restrictions on active management in northern spotted owl habitata

Limited management in reserves and wildernessRisks associated with prescribed fireLack of resources for planting a higher diversity of tree speciesRestrictive seed zone planting policies

Information on changes in lightning frequency with climate change

Strategy: Increase monitoring of specialist species that are expected to be sensitive to climate change.

• Identify climate refugia• Adjust monitoring protocols to detect species’ 

responses to climate change

• Increase monitoring to attribute population 

changes to climate change vs. other threats

Methods for monitoring threatened and endangered species that allow for attribution of changes to climate vs. other threatsIncreased confidence in location of northern spotted owl nest sitesMonitoring protocol to detect species range shifts

a USDA and USDI (1994).
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designed with the notion of static ecosystems and do not reflect the increased 

dynamism of these systems as climate changes (Mawdsley et al. 2009). This has 

been recognized as a limitation of the NWFP for protecting late-successional 

habitat in fire-adapted forests of the eastern Cascades. The extent of fire and insect 

disturbances in low-elevation maritime forests has not caused substantial loss of 

late-successional habitat, but climate change will increase the probability of such 

events. However, management in reserves will need to consider tradeoffs between 

short-term effects on threatened and endangered species and long-term benefits of 

increased resilience to disturbance. 

Management actions to increase resilience to climate change, such as increased 

use of prescribed fire and unplanned ignitions, and planting species or varieties 

that are adapted to a warmer climate, will have additional ecological and social 

risks. Research is needed to determine which species to plant and how to modify 

seed zone restrictions. A better understanding of the ecological effects of fire in 

forests not historically adapted to frequent fire can inform prescriptions for fire and 

thinning treatments to achieve desired future conditions in low-elevation maritime 

forests. 

Adaptation to climate change can be facilitated by altering inventory and 

monitoring procedures to focus on species and habitats that are likely to be most 

sensitive (Heller and Zavaleta 2009). For example, specialists and endemic species 

are expected to be more sensitive because of their generally narrow habitat requirements. Identifying climate refugia can aid prioritization of critical areas to protect 

(Heller and Zavaleta 2009). Monitoring procedures can be modified to include measures and indicators that distinguish between the effects of climatic and nonclimatic 

stressors on populations. This is particularly important for developing adaptation 

strategies in national parks because current NPS policies generally restrict intervention to manage unnaturally high or low populations only when fluctuations are 

caused by humans, not by natural processes and competition. Additional research is 

needed to design monitoring protocols to detect shifts in species ranges and effects 

and associated effects on ecological function, as well as attributing changes to 

climatic versus nonclimatic stressors.

Adaptation Options for East-Side Fire-Adapted Forest Habitat 

and Associated Species

Fire-adapted forests on the eastern slopes of the Cascade Range have recently 

experienced loss of late-successional habitat because of large and severe insect outbreaks and fires. These disturbances have shifted a greater portion of the landscape 
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to earlier successional forests relative to the historical range of variability (Hessburg 

et al. 2005), and large areas of late-successional habitat set aside as reserves under 

the NWFP have been lost. The extent and connectivity of late-successional habitat 

are also threatened by development and land use change. Increasing the resistance 

and resilience of fire-adapted forests can limit habitat loss to insect outbreaks and 

fire, especially if these concepts are incorporated in management plans (Dale et 

al. 2001, Mawdsley et al. 2009). Actions to increase resilience include thinning 

dense forests, removing accumulated surface fuels (e.g., with prescribed fire), and 

allowing wildfire to burn in areas where it can beneficially increase diversity in 

forest structure (table 6.2). The forest restoration and fire programs in fire-adapted 

forests in OWNF and NOCA currently manage fire as a natural ecosystem process. 

The OWNF Restoration Strategy and revised forest plan emphasize the additional 

threat to late-successional habitat associated with more disturbances in a changing 

climate. Recent modifications to the NWFP recognize the need to manage latesuccessional habitat in fire-adapted forests as a dynamic system (Spies et al. 2006). 

Maintaining late-successional habitat in fire-adapted forests will be most successful 

with a large-scale approach to restoration and protection that recognizes the need to 

protect critical remnant habitat in some locations while accepting short-term loss in 

other locations with treatments to increase resilience in the long-term. 

Habitat fragmentation caused by urban development limits the ability of species 

to migrate and shift their ranges as climate changes (Noss 2001). Thus, increasing habitat connectivity is the most commonly recommended adaptation strategy 

for wildlife (Heller and Zavaleta 2009) and managers identified connectivity as a 

critical adaptation strategy for many species in east-side fire-adapted forests (table 

6.2). Climate change provides a new context with which to evaluate current objectives and practices for increasing connectivity. Increasing connectivity requires 

approaches that are tailored to specific species or groups of species. In a changing 

climate, managers may consider focusing efforts on species with limited dispersal 

abilities or species that are sensitive to climate change. For these species, the corridors and core habitats designated under current climate may not be as effective 

in the future as climate, vegetation, and hydrologic regimes change. Furthermore, 

climate change increases the importance of working across jurisdictions to increase 

connectivity because it will not be possible to preserve all species in all places. 

Managing connectivity will require an “all lands” approach that coordinates 

management among ownerships to protect existing habitat in reserves and increase 

the permeability of the matrix and unprotected lands so that species can migrate 

(Hannah et al. 2002). 

Resilience in dry 

forests can be 

increased by thinning, 

removing surface fuels, 

and allowing wildfire 

to burn in areas where 

it can diversify forest 

structure.
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Table 6.2—Climate change sensitivities of east-side fire-adapted forests habitat; adaptation strategies and tactics to reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Loss of late-successional forest habitat and greater habitat fragmentation because of increase in wildfire area. 

Strategy: Increase resilience of latesuccessional forests and surrounding habitat in dry fire-adapted forests.

• Increase resilience of surrounding forests 

with thinning and prescribed burning

• Increase fuel reduction treatments in 

urban growth boundaries

• Increased use of wildfire for ecological 

benefits

Okanogan-Wenatchee National Forest (OWNF) restoration strategy a and 

revised forest plan b

New and existing landscape restoration collaborations

Lack of adaptive managementLack of a market for biomass and materials harvested in treatmentsAir quality restrictionsPublic aversion to smokeRestrictions on managing natural ignitions outside of wilderness

Effects of vegetation treatments on focal speciesQuantification of smoke emissions and exposure from wildfire vs. prescribed fire

Strategy: Increase resistance of latesuccessional forest habitat in fire-adaptedforests strategically across the region.

• Protect remnant habitat from fire and 

insect outbreaks

• Manage and plan growth in the wildlandurban interface• Increase management of human ignition 

sources

• Increase use of conservation easements

OWNF restoration strategya and 

revised forest plan,b

New and existing landscape restoration collaborations

Lack of public acceptance of climate change

Sensitivity: Shifts in species ranges and loss of species functional types (e.g., pollinators).

Strategy: Increase habitat connectivity and permeability.

• Increase use of conservation easements• Increase road closures and restrictions on 

access in critical habitats

• Accept loss of some facets of ecosystem 

to protect others

Research from the Washington Wildlife Habitat Connectivity Working Group (WHCWG)OWNF restoration strategy a and 

revised forest planb

Exiting barriers to connectivity (e.g., roads)Private landowner resistanceResistance to land acquisitionCompetes with human access

Fine-scale analyses of the statewide products from the WHCWG

a USDA FS (2012b).b USDA FS (2011).
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Habitat connectivity and permeability of the matrix can be increased through 

conservation easements, planning and management of urban growth boundaries, restrictions on human use, and road closures to protect critical areas. New 

and existing landscape restoration efforts that involve multiple agencies provide 

an opportunity to address habitat connectivity across jurisdictional boundaries. National forests and national parks in the NCAP are part of the Washington 

Wildlife Habitat Connectivity Working Group, which is researching critical corridors and migration pathways that will allow species to shift ranges as climate 

changes (WHCWG 2011). A fine-scale analysis for specific species and habitats 

could inform adaptation tactics and priority locations for corridors and core habitat 

protection. 

Although increasing connectivity is a critical adaptation strategy, potential 

tradeoffs will need to be considered. Increasing connectivity for native species of 

concern may also increase the spread of invasive species, particularly those that 

will benefit from a warmer climate with more disturbances. Actions to increase 

connectivity and permeability in the matrix may compete with human access and 

development and could be met with public opposition, particularly where skepticism 

about climate change exists. An “all-lands” approach to managing for habitat connectivity is likely to be more successful if it includes public outreach and education 

on the effects of climate change on wildlife and habitat. 

Adaptation Options for Riparian Forest Habitat and Associated 

Species

Changes in hydrologic regimes will affect riparian habitats and riparian obligate 

species in forests on both the west and east sides of the Cascade Range. More frequent floods and higher peak flows could reduce riparian habitat in forests on the 

western slopes, particularly areas in mixed rain-and-snow basins that will experience the biggest shift in winter precipitation falling as rain rather than snow (see 

chapter 4). In these basins, adaptation tactics that increase water storage in uplands 

to regulate runoff can be considered (table 6.3). One tactic is to manage for larger 

beaver populations that create functional wetlands that store water. Beavers that 

build dams that destroy roads and trails could be relocated rather than eliminated. 

Drier forests on the eastern slopes of the Cascades are also likely to experience 

changes in hydrologic regimes that will affect riparian habitats and species. Lower 

snowpack, water availability in the summer, and summer streamflows (see chapter 

4) will reduce the function of riparian habitat in drier forests. Similar to the west 

side, it may be desirable to increase water storage on the landscape in winter to 

maintain summer water availability and streamflow, and again, maintaining higher 

beaver populations and the wetland habitats they create would be a useful tactic. 

Habitat connectivity 

for wildlife can be 

increased through 

conservation 

easements, planning 

for urban growth 

boundaries, and 

restrictions on human 

use and access.
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Table 6.3—Climate change sensitivities of riparian forests and riparian obligate species; adaptation strategies and tactics to reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Increased flooding impacts on riparian habitats (west side).

Strategy: Increase upland water storage by managing 

for greater beaver populations.

• Accommodate and maintain higher beaver

populations

• Trap and relocate beavers that create dams that 

flood trails

No funding to maintain beaver populations Baseline population data on beavers

Sensitivity: Loss of riparian habitat leading to declining populations of riparian obligate species (east side).

Strategy: Reduce riparian impacts by storing more 

water on the landscape.

• Increase beaver populations to create more

wetland habitat

• Use snow fences and reflective tarps to retain 

snow in critical areas

Water conservation efforts Projections of water availability 

for east-side forest ecosystems with climate change
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Another tactic in areas where snowpack is critical is to use reflective tarps or other 

devises to retain snow. Funding for such intensive management is not currently 

available, but if riparian systems become severely compromised by climate change, 

it may be possible to justify this investment.

Adaptation Options for Wetland Habitats and Associated Species

Wetlands in the North Cascades are likely to experience changes in hydroperiods 

as the climate changes. Wetlands provide critical habitat for wildlife, including 

many amphibian species that are likely to be sensitive to climate change. Workshop 

participants identified adaptation strategies and tactics to reduce adverse impacts 

on wetland habitats and species in general and specifically for the western toad 

(table 6.4). Increasing resilience and resistance of populations of wetland obligate 

species in response to changes in breeding habitat and survival rates would facilitate adaptation to climate change (Corn 2005). Additional research on the current 

distribution of wetlands, changes in wetland hydrology, and methods to reduce 

climate change effects will facilitate implementation of adaptation strategies. 

Reducing nonclimatic stressors is a commonly identified adaptation strategy 

because it is robust to a range of future climate scenarios and is often consistent 

with current ecosystem management practices (Heller and Zavaleta 2009, Peterson 

et al. 2011). Existing efforts in NOCA to reduce introduced fish species in high-elevation lakes exemplify how reducing a nonclimatic stressor can increase resilience 

to climate change (USDI NPS 2006a). Reducing the threat posed by introduced fish 

species to mountain lake and wetland community dynamics is a low-risk, robust 

strategy for increasing resilience (Hoffman et al. 2004). Restoration of wetland 

habitats following timber harvest can improve habitat quality. Some wetlands in 

the region have been adversely affected by the high density of roads and trails and 

heavy recreation use. Limiting visitation and closing roads and trails near sensitive 

wetlands can increase resilience. In many cases, reducing nonclimatic stressors can 

increase resilience to climate change, but simply continuing current conservation 

and ecosystem management practices without explicit consideration of climate 

change will likely be insufficient. 

Higher water temperature in lakes and streams may increase rates of disease 

and fungal and bacterial infections (Blaustein et al. 2010). Closing roads and trails, 

limiting human access, and educating the public about the sensitivity of wetland 

communities may reduce the spread of pathogens. Intensive management, such as 

managed relocation of wetland species, may be necessary to protect high-value rare 

and sensitive species or populations over the long term (Mawdsley et al. 2009).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Climate change will likely alter phenology and species interactions, thus 

changing community dynamics in wetlands (Blaustein et al. 2010). Maintaining 

biological diversity within these systems is one strategy to increase resilience of 

ecological functions and allow the systems to better respond to changes in climate 

(Mawdsley et al. 2009). Increased monitoring of population trends and habitat 

conditions can inform prioritization of critical regions, locations, and species to 

manage as the climate changes. Adaptive management protocols can be useful 

for periodically reviewing and adjusting management priorities and objectives as 

population changes are measured. Resource managers in NCAP national forests and 

national parks are seeking opportunities to coordinate priorities, monitoring, and 

management across jurisdictional boundaries, so that biodiversity is maintained in a 

regional context, rather than separately for each unit (Lawler et al. 2009). 

Adaptation strategies for the western toad, an aquatic breeding amphibian species, are similar to those for wetland habitats and species in general, but additional 

measures can be taken to facilitate adaptation of this species (table 6.4). Maintaining wetland hydrology by managing snowpack with fences and water levels in 

systems linked to reservoirs can protect aquatic breeding habitat. Using wetland 

vegetation to increase shade can reduce temperature and moisture stress and protect 

microhabitats within wetlands (Shoo et al. 2011). Habitat enhancement with woody 

debris can increase microhabitat structures for climate refugia and egg deposition, 

thus increasing breeding sites and reproduction (Shoo et al. 2011). 

Survival in all life stages can be enhanced with actions to minimize disease 

spread, manage toadlet migration, and increase invertebrate prey resources. The 

spread of fungi and pathogens between ponds can be reduced with decontamination, visitor education (e.g., advising swimmers to swim in one pond per visit), and 

microbial treatments of amphibians at small scales (Harris et al. 2009). Populations 

can be protected with road or campground closures during critical periods of toadlet 

migration. Removing exotic fish from ponds and lakes may also increase invertebrate prey resources for native amphibians (Knapp et al. 2001). Although many 

of these actions are already taken at small scales, increasing stress on amphibian 

populations because of climate change may require that these actions be taken in 

more locations or more often to ensure population resilience. 

Current national forest and national park management objectives for wetlands 

and associated species present both barriers and opportunities to implementing 

these adaptation strategies (table 6.4). National Park Service policies limit intensive 

management of species and habitat components such as vegetation or snowpack, 

but the policies direct managers to mitigate adverse impacts of human actions. 

Thus, NPS managers have the authority to manage trails, roads, infrastructure, and 

Removing exotic fish 

species from ponds 

and lakes may increase 

invertebrate prey for 

native amphibians.
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general technical report pnw-gtr-892 Table 6.4—Climate change sensitivities of wetland habitat and wetland obligate species; adaptation strategies and tactics to reduce impacts Adaptation tactics Opportunities for implementation Barriers to implementation Information needs Sensitivity: Reduced embryonic and larval survival because of changes in breeding habitat. Strategy: Increase population resilience and resistance. • Reduce nonclimatic threats • Remove exotic fish • Facilitate recovery from past management with habitat manipulation • Relocate species as necessary Fish removal and adaptive manage- ment under existing North Cascades Mountain Lakes Fishery Management Plan/environmental impact statementa Post-harvest wetland recovery projects Public opposition to intensive management and using pesti- cides in lakes Identification of priority sites for fish removals Sensitivity: Increased prevalence of disease and fungal and bacterial infections with associated mortality.

Strategy: Increase resilience to disease and pathogens. 

• Use devices to retain snowpack near sensitive 

habitat

• Educate the public about disease sensitivities• Manage or limit recreation and other use 

through closures or other means

Educational partnerships with amphibian and reptile conservation groups Limited opportunities for Na- tional Park Service (NPS) active 

management of snowpack and vegetationLimited funding

Sensitivity: Changes in phenology and species interactions (e.g., predation, competition) of wetland obligate species.

Strategy: Increase resilience by preserving biodiversity.

• Identify important habitat manipulations 

based on monitoring

• Protect critical areas

Wilderness policies limit intensive management

Strategy: Monitor and prioritize regions for wetlands management

• Prioritize habitats for active management and 

protection across jurisdictional boundaries

• Focus monitoring on sensitive habitats and 

species in priority regions

• Periodically review and revise priorities

Agency mandates for adaptive managementPostharvest wetland recovery projects

Limited funding for monitoring programs

Cumulative effects of generalized stress on endocrine function in amphibians
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Adaptation tactics Opportunities for implementation Barriers to implementation Information needs

Strategy: Increase population resilience by 

reducing nonclimatic threats.

• Manage road, trail, and recreation impacts• Maintain hydrology of critical habitats• Increase habitat connectivity and

heterogeneity

Methods for maintaining hydrology of wetlands

Strategy: Increase resilience to changes in 

temperature and hydroperiod by enhancing breeding sites. 

• Use vegetation to increase shading of wetlands and microhabitats 

• Retain water levels in wetlands when controlled by reservoir systems• Increase microhabitat structures (e.g., woody 

debris) for microclimate refugia, nesting habitat, and egg deposition structures

Different agency mandates (e.g., 

NPS vs. U.S. Department of Agriculture Forest Service); NPS needs to prove human influence to justify active management

Increased understanding of microhabitat requirements for amphibians

Sensitivity: Fluctuating nutrient levels, episodic acidification, exacerbated disease dynamics, and decreased prey for Bufo boreas.

Strategy: Maintain and enhance habitat quality 

to boost survival of all life stages.

• Use decontamination procedures and consider 

microbial treatments

• Provide dispersal cover between aquatic and 

upland habitats

• Maintain burrowing mammal habitats• Manage for toadlet migration• Increase invertebrate prey resources

Required management to protected species listed under the Endangered Species Actb

Research on methods for increasing prey resources Ecological effects of microbial treatments Population trajectories for burrowing mammals 

a USDI NPS 2006a.bTable 6.4—Climate change sensitivities of wetland habitat and wetland obligate species; adaptation strategies and tactics to reduce 

 ESA 1973.

impacts (continued)
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recreational uses that are reducing wetland habitat extent and quality and spreading 

diseases. Similarly, NPS managers have the authority to remove exotic species and 

intervene to protect state and federally listed species. In the case of direct effects of 

climate change on wetlands and species, attributing these changes to human-caused 

climate change would provide NPS with the authority to mitigate the effects. The 

NPS can intervene to protect threatened and endangered species, so the ESA (1973) 

provides an opportunity to implement adaptation strategies designed to increase 

resilience of threatened and endangered species to climate change. The USDA FS 

policies provide more options to actively manage habitat outside of wilderness and 

reserves. Current wetland restoration plans following timber harvests provide an 

opportunity to evaluate the likelihood of achieving desired objectives given projected changes in climate. 

Adaptation Options for Alpine and Subalpine Habitats and 

Associated Species

Increased monitoring of alpine and subalpine habitats and associated wildlife species will be needed to quantify the effects of climate change. Monitoring can detect 

changes in the distribution and abundance of alpine and subalpine habitat. Monitoring specifically designed to detect effects of climate change on subalpine and alpine 

habitats could measure tree encroachment in meadows, changes in upper treeline, 

soil development, and establishment of herbaceous species in areas that were previously occupied by perennial snow or glaciers (table 6.4). 

Intervention could be deemed necessary to protect critical habitat and species. 

Adaptation tactics for increasing habitat resilience include intensive management 

to remove trees from meadows with fire or mechanical treatments (table 6.4). 

Some subalpine and alpine ecosystems in the region are experiencing nonclimatic 

threats associated with trails and human use. Access to these areas can be restricted 

to increase habitat resilience. Summer range for elk includes subalpine habitats, 

but the winter range of elk at lower elevations is often outside the boundaries of 

national forests and national parks. This example illustrates that climate change 

may require greater collaboration between resource management agencies and 

in some cases private landowners to mitigate effects on species with large ranges 

(Hannah et al. 2002). USDA FS and NPS managers will explore opportunities to 

increase collaborative efforts with other agencies and landowners to identify and 

protect winter habitat for elk in an effort to decrease the effects of reduced summer 

habitat on elk populations. 

Adaptation strategies focused on alpine and subalpine habitat may be needed 

to protect some species that are typically associated with high-elevation vegetation 

(table 6.5). Limited connectivity between isolated alpine and subalpine habitats 

Collaboration between 

agencies and in 

some cases private 

landowners will be 

needed to mitigate 

climate change effects 

on species with large 

ranges. 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 6.5—Climate change sensitivities of subalpine and alpine habitat and species; adaptation strategies and tactics to reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Tree establishment in subalpine meadows and decreasing forage for pika and marmot.

Strategy: Maintain and protect summer alpine habitat for pika and marmot.

• Monitor tree establishment in meadows• Remove trees from meadows using fire and

mechanical treatments

• Monitor soil development, cryptobiotic crust, 

and herbaceous plant establishment in previously snow-covered and glaciated areas

• Decrease visitor use in alpine and subalpine 

habitats

Fire management plans that include more use of fire

Limited opportunities for active management in wildernessAir quality restrictions associated with prescribed firePublic perception of and opposition to active management

Tree establishment rates in burned areasEffectiveness of treatments for increasing summer forage.Research on connectivity to other sites

Strategy: Increase population resilience of subalpinedependent species. 

• Increase education and regulatory enforcement to 

prevent adverse human-wildlife interactions 

• Augment currently stressed populations of mountain goats from populations that are larger and 

more robust

Sensitivity: Declining area of summer range for ungulate species.

Strategy: Conserve winter range for ungulate species.

• Identify critical winter habitat for ungulate

species 

• Increase collaboration with partners to conserve 

critical winter habitat

Information on winter morality rates for ungulate herdsInformation on changes in quality and quantity of summer forageResearch on connectivity to other sites
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decreases the ability of species to migrate. In the case of species with high social, 

political, or ecological value, managers may need to consider assisted migration 

or preserving species ex situ. Human-wildlife interactions such as feeding, habituation, and traffic accidents adversely affect populations. Reducing nonclimatic 

threats from human-wildlife interactions through greater public education and 

enforcement can increase population resilience and help maintain some species. 

Some populations of a species may be more affected by climate change than others, 

thus long-term management could include augmenting declining populations with 

individuals from thriving populations elsewhere in the region. For example, mountain goat populations in some areas of the North Cascades are well below historical 

levels, and wildlife managers are considering augmenting these populations, an 

effort that would require a regional focus to climate change adaptation.

Acknowledgments

We thank members of the natural resource staffs at Mount Baker-Snoqualmie 

National Forest, Okanogan-Wenatchee National Forest, North Cascades National 

Park Complex, and Mount Rainier National Park for their expertise and input 

during workshops and subsequent discussions, including Andrea Lyons, Barbara 

Samora, Bill Gaines, Bob Kuntz, Jesse Plumage, Mason Reid, and Phyllis Reed. We 

also thank several regional experts for their contributions to the vegetation workshop including John Lehmkuhl and Meade Krosby. Robert Hoffman, Patty Glick, 

and Jesse Plumage provided helpful reviews of this chapter. 

Literature Cited

Amarasekare, P. 2003. Competitive coexistence in spatially structured 

environments: a synthesis. Ecology Letters. 6: 1109–1122.

Bahls, P. 1992. The status of fish populations and management of high mountain 

lakes in the Western United States. Northwest Science. 66: 183–193.

Bates, B.C.; Kundzewicz, Z.W.; Wu, S.; Palutikof, J.P., eds. 2008. Climate 

change and water. Technical Paper IPCC VI. Geneva, Switzerland: 

Intergovernmental Panel on Climate Change. 210 p.

Beever, E.A.; Brussard, P.F.; Berger, J. 2003. Patterns of apparent extirpation 

among isolated populations of pikas (Ochotona princeps) in the Great Basin. 

Journal of Mammalogy. 84: 37–54.

Beever, E.A.; Ray, C.; Mote, P.W.; Wilkening, J.L. 2010. Testing alternative 

models of climate-mediated extirpations. Ecological Applications. 20: 164–178.
225

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Berger, L.; Speare, R.; Hines, H.B. [et al.] 2004. Effect of season and 

temperature on mortality in amphibians due to chytridiomycosis. Australian 

Veterinary Journal. 82: 434–439.

Beschta, R.L.; Ripple, W.J. 2012. The role of large predators in maintaining 

riparian plant communities and river morphology. Geomorphology. 157–158: 

88–98.

Blaustein, A.R.; Romansic, J.M.; Scheessele, E.A. [et al.]. 2005. Interspecific 

variation in susceptibility of frog tadpoles to the pathogenic fungus 

Batrachochytrium dendrobatidis. Conservation Biology. 19: 1460–1468.

Blaustein, A.R.; Wake, D.B. 1990. Declining amphibian populations: A global 

phenomenon? Trends in Ecology and the Environment. 5: 203–204.

Blaustein, A.R.; Walls, S.C.; Bancroft, B.A. [et al.]. 2010. Direct and indirect 

effects of climate change on amphibian populations. Diversity. 2: 281–313.

Bronson, F.H. 2009. Climate change and seasonal reproduction in mammals. 

Philosophical Transactions of the Royal Society B: Biological Sciences. 364: 

3331–3340.

Brooks, D.R.; Hoberg, E.P. 2007. How will global climate change affect parasitehost assemblages? Trends in Parasitology. 23: 571–574.

Bradley, B.A. 2009. Regional analysis of the impacts of climate change on 

cheatgrass invasion shows potential risk and opportunity. Global Change 

Biology. 15: 196–208.

Bull, E. 2009. Dispersal of newly metamorphosed and juvenile western toads 

(Anaxyrus boreas) in northeastern Oregon, USA. Herpetological Conservation 

and Biology. 4: 236–247.

Calfee, R.D.; Bridges, C.M.; Little, E.E. 2006. Sensitivity of two salamander 

(Ambystoma) species to ultraviolet radiation. Journal of Herpetology. 40: 35–42.

Canto, T.; Aranda, M.A.; Fereres, A. 2009. Climate change effects on physiology 

and population processes of hosts and vectors that influence the spread of 

hemipteran-borne plant viruses. Global Change Biology. 15: 1884–1894.

Carpenter, S.R.; Fisher, S.G.; Grimm, N.B. 1992. Global change and freshwater 

ecosystems. Annual Review of Ecology and Systematics. 23: 119–139.

Carroll, C. 2010. Role of climatic niche models in focal-species-based conservation 

planning: assessing potential effects of climate change on northern spotted owl 

in the Pacific Northwest, USA. Biological Conservation. 143: 1432–1437.
226

general technical report pnw-gtr-892

Chen, I.C.; Hill, J.K.; Ohlemueller, R. [et al.]. 2011. Rapid range shifts of species 

associated with high levels of climate warming. Science. 333: 1024–1026.

Chesson, P. 2000. General theory of competitive coexistence in spatially varying 

environments. Theoretical Population Biology. 58: 211–237.

Corn, P.S. 2005. Climate change and amphibians. Animal Biodiversity and 

Conservation. 28: 59–67.

Dale, V.H.; Joyce, L.A.; McNulty, S. [et al.]. 2001. Climate change and forest 

disturbances. BioScience. 51: 723–734.

Davidson, C.; Shaffer, H.B.; Jennings, M.R. 2001. Declines of the California 

red-legged frog: climate, UV-B, habitat, and pesticides hypotheses. Ecological 

Applications. 11: 464–479. 

Duarte, H.; Tijedo, M.; Katzenberger, M. [et al.]. 2012. Can amphibians take 

the heat? Vulnerability to climate warming in subtropical and temperate larval 

amphibian communities. Global Change Biology. 18: 412–421.

Dukes, J.S.; Mooney, H.A. 1999. Does global change increase the success of 

biological invaders? Trends in Ecology and Evolution. 14: 135–139.

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.

Endangered Species Act of 1973 [ESA]; 16. U.S.C. 1531-1536, 1538-1540.

Erb, L.P.; Ray, C.; Guralnick, R. 2011. On the generality of a climate-mediated 

shift in the distribution of the American pika (Ochotona princeps). Ecology. 92: 

1730–1735.

Froeschke, G.; Harf, R.; Sommer, S.; Matthee, S. 2010. Effects of precipitation 

on parasite burden along a natural climatic gradient in southern Africa–

implications for possible shifts in infestation patterns due to global changes. 

Oikos. 119: 1029–1039.

Garrett, K.A.; Dendy, S.P.; Frank, E.E. [et al.]. 2006. Climate change effects on 

plant disease: genomes to ecosystems. Annual Review of Phytopathology. 44: 

489–509.

Glick, P.; Stein, B.A.; Edelson, N.A., eds. 2011. Scanning the conservation 

horizon: a guide to climate change vulnerability assessment. Washington, DC: 

National Wildlife Federation. 168 p.
227

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Guscio, G.C.; Hossack, B.R.; Eby, L.A.; Corn, P.S. 2007. Post-breeding habitat 

use by adult boreal toads (Bufo boreas) after wildfire in Glacier National Park, 

USA. Herpetological Conservation and Biology. 3: 55–62.

Halofsky, J.E.; Peterson, D.L.; O’Halloran, K.A.; Hoffman, C.H. 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.

Hannah, L.; Midgley, G.F.; Millar, D. 2002. Climate change-integrated 

conservation strategies. Global Ecology and Biogeography. 11: 485–495.

Hansen, L.J.; Hoffman, J.R. 2011. Climate savvy: adapting conservation and 

resource management to a changing world. Washington, DC: Island Press. 256 p.

Haroldson, M.A.; Ternent, M.A.; Gunther, K.A.; Schwartz, C.C. 2002. Grizzly 

bear denning chronology and movements in the Greater Yellowstone Ecosystem. 

Ursus. 13: 29–37.

Harris, R.N.; Lauer, A.; Simon M.A. [et al.]. 2009. Addition of antifungal skin 

bacteria to salamanders ameliorates the effects of chytridiomycosis. Diseases of 

Aquatic Organisms. 83: 11–16.

Heller, N.E.; Zavaleta, E.S. 2009. Biodiversity management in the face of climate 

change: a review of 22 years of recommendations. Biological Conservation. 142: 

14–32.

Hellmann, J.J.; Byers, J.E.; Bierwagen, B.G.; Dukes, J.S. 2008. Five potential 

consequences of climate change for invasive species. Conservation Biology. 22: 

534–543. 

Hessburg, P.F.; Agee, J.K.; Franklin, J.F. 2005. Dry forests and wildland fires of 

the inland Northwest, USA: contrasting the landscape ecology of pre-settlement 

and modern eras. Forest Ecology and Management. 211: 117–139.

Hillman, S.; Withers, P.; Drewes, R.; Hillyard, S. 2009. Ecological and 

environmental physiology of amphibians. Oxford, United Kingdom: Oxford 

University Press. 464 p.

Hoffman, R.L.; Larson, G.L.; Samora, B. 2004. Responses of Ambystoma gracile

to the removal of introduced nonnative fish from a mountain lake. Journal of 

Herpetology. 38: 578–585.
228

general technical report pnw-gtr-892

Inouye, D.W.; Barr, B.; Armitage, K.B.; Inouye, B.D. 2000. Climate change 

is affecting altitudinal migrants and hibernating species. Proceedings of the 

National Academy of Sciences of the United States of America. 97: 1630–1633.

Kareiva, P.; Kingsolver, J.G.; Huey, R.B. 1993. Biotic interactions and global 

change. Sunderland, MA: Sinauer Associates, Inc. 480 p.

Kilpatrick A.M.; Briggs, C.J.; Daszak, P. 2010. The ecology and impact of 

chytridiomycosis: an emerging disease of amphibians. Trends in Ecology and 

Evolution. 25: 109–118.

Knapp, R.A. 1996. Nonnative trout in natural lakes of the Sierra Nevada: an 

analysis of their distribution and impacts on native aquatic biota. In: Sierra 

Nevada Ecosystem Project: final report to Congress. Volume III. Davis, CA: 

University of California, Davis, Centers for Water and Wildland Resources: 

363–407.

Knapp, R.A.; Matthews, K.R.; Sarnelle, O. 2001. Resistance and resilience of 

alpine lake fauna to fish introductions. Ecological Monographs. 71: 401–421

Kupferberg, S.J.; Palen, W.J.; Lind, A.J. [et al.]. 2012. Effects of flow regimes 

altered by dams on survival, population declines, and range-wide losses of 

California river-breeding frogs. Conservation Biology. 26: 513–524.

Lacan, I.; Matthews, K.; Feldman, K. 2008. Interaction of an introduced 

predator with future effects of climate change in the recruitment dynamics of 

the imperiled Sierra Nevada yellow-legged frog (Rana sierrae). Herpetological 

Conservation and Biology. 3: 211–223.

Lafferty, K.D. 2009. The ecology of climate change and infectious diseases. 

Ecology. 90: 888–900.

Lawler, J.J.; Shafer, S.L.; Bancroft, B.A.; Blaustein, A.R. 2010. Projected 

climate impacts for the amphibians of the Western Hemisphere. Conservation 

Biology. 24: 38–50.

Lawler, J.J.; Shafer, S.L.; White, D. [et al.]. 2009. Projected climate-induced 

faunal change in the western hemisphere. Ecology. 90: 588–597.

Leonard, W.P.; McAllister, K.R. 2005. Oregon spotted frog, Rana pretiosa, 

Baird and Girard. In: Jones, L.L.C.; Leonard, W.P. Leonard; Olson, D.H., eds. 

Amphibians of the Pacific Northwest. Seattle, WA: Seattle Audubon Society: 

210–213.
229

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Littell, J.S.; McKenzie, D.; Peterson, D.L.; Westerling, A.L. 2009. Climate 

and wildfire area burned in western U.S. ecoprovinces, 1916–2003. Ecological 

Applications. 19: 1003–1021.

Littell, J.S.; Peterson, D.L.; Millar, C.I.; O’Halloran, K.A. 2012. U.S. national 

forests adapt to climate change through science-management partnerships. 

Climatic Change. 110: 269–296.

Mantua, N.; Tohver, I.; Hamlet, A. 2010. Climate change impacts on streamflow 

extremes and summertime stream temperature and their possible consequences 

for freshwater salmon habitat in Washington state. Climatic Change. 102: 

187–223.

Marcogliese, D.J. 2001. Implications of climate change for parasitism of animals 

in the aquatic environment. Canadian Journal of Zoology. 79: 1331–1352.

Matthews, J.H.; Funk, W.C.; Ghalambor, C.K. 2010. Demographic approaches 

to assessing climate change impact: an application to pond-breeding frogs 

and shifting hydropatterns. In: Brodie, J.F.; Post, E.; Doak, D., eds. Wildlife 

conservation in a changing climate. Chicago, IL: University of Chicago Press: 

58–85.

Mawdsley, J.R.; O’Malley, R.; Ojima, D.S. 2009. A review of climate-change 

adaptation strategies for wildlife management and biodiversity conservation. 

Conservation Biology. 5: 1080–1089.

McCaffery, R.M.; Maxell, B.A. 2010. Decreased winter severity increases 

viability of montane frog population. Proceedings of the National Academy of 

Sciences of the United States of America. 10: 8644–8649.

McKelvey, K.S.; Copeland, J.P; Schwartz, M.K. [et al.]. 2011. Climate change 

predicted to shift wolverine distributions, connectivity, and dispersal corridors. 

Ecological Applications. 21: 2882–2897.

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.

Moritz, C.; Patton, J.L.; Conroy, C.J. [et al.]. 2008. Impact of a century of 

climate change of small-mammal communities in Yosemite National Park, USA. 

Science. 322: 261–264.

Mote, P.W. 2003. Trends in snow water equivalent in the Pacific Northwest and 

their climatic causes. Geophysical Research Letters. 30: 1601–1604.
230

general technical report pnw-gtr-892

Mote, P.W.; Salathé, E.P.J. 2010. Future climate in the Pacific Northwest. Climatic 

Change. 102: 29–50.

Naiman, R.J.; Rogers, K.H. 1997. Large animals and system-level characteristics 

in river corridors. BioScience. 47: 521–529.

National Environmental Policy Act of 1969 [NEPA]; 42 U.S.C. 4321 et seq.

National Park Service Organic Act of 1916 [NPS]; 39 Stat. 535; 16 U.S.C. 

1,2,3, and 4. 

Nitschke, C.R.; Innes, J.L. 2008. Climatic change and fire potential in southcentral British Columbia, Canada. Global Change Biology. 14: 841–855.

Noss, R.F. 2001. Beyond Kyoto: forest management in a time of rapid climate 

change. Conservation Biology. 15: 578–590.

Ouellet, M.; Mikaelian, I.; Pauli, B.D. [et al.]. 2005. Historical evidence of 

widespread chytrid infection in North American amphibian populations. 

Conservation Biology. 19: 1421–1440.

Palen, W.J.; Schindler, D.E. 2010. Water clarity, maternal behavior, and 

physiology combine to eliminate UV radiation risk to amphibians in a 

montane landscape. Proceedings of the National Academy of Sciences, USA. 

107: 9701–9706.

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.

Pearl C.A.; Bowerman J.; Adams, M.J.; Chelgren, N.D. 2009. Widespread 

occurrence of the chytrid fungus Batrachochytrium dendrobatidis on Oregon 

spotted frogs (Rana pretiosa). Ecohealth. 6: 209–218.

Pearl, C.A.; Bull, E.L.; Green, D.E. [et al.]. 2007. Occurrence of the amphibian 

pathogen Batrachochytrium dendrobatidis in the Pacific Northwest. Journal of 

Herpetology. 41: 145–149.
231

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al.]. 2011. Responding to climate 

change in national forests: a guidebook for developing adaptation options. Gen. 

Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 109 p.

Poff, N.L.; Brinson, M.M.; Day, J.W., Jr. 2002. Aquatic ecosystems and global 

climate change: potential impacts on inland freshwater and coastal wetland 

ecosystems in the United States. Arlington, VA: Pew Center on Global Climate 

Change. 45 p.

Pounds, A.J.; Crump, M.L. 1994. Amphibian declines and climate disturbance: 

the case of the golden toad and the harlequin frog. Conservation Biology. 8: 

72–85.

Pounds, J.A.; Fogden, M.P.L.; Campbell, J.H. 1999. Biological response to 

climate change on a tropical mountain. Nature. 398: 611–615.

Richter, K.O.; Azous, A.L. 2001a. Amphibian distribution, abundance, and habitat 

use. In: Azous, A.L.; Horner, R.R., eds. Wetlands and urbanization: implications 

for the future. New York: Lewis Publishers: 143–166. Chapter 5.

Richter, K.O.; Azous, A.L. 2001b. Bird distribution, abundance, and habitat use. 

In: Azous A.L.; Horner, R.R., eds. Wetlands and urbanization: implications for 

the future. New York: Lewis Publishers: 167–200. Chapter 6. 

Richter, K.O.; Azous, A.L. 2001c. Terrestrial small mammal distribution, 

abundance, and habitat use. In: Azous A.L.; Horner, R.R., eds. Wetlands and 

urbanization: implications for the future. New York: Lewis Publishers: 201–220. 

Chapter 7.

Rogers, B.M.; Neilson, R.P.; Drapek, R. [et al.]. 2011. Impacts of climate change 

on fire regimes and carbon stocks of the U.S. Pacific Northwest. Journal of 

Geophysical Research—Biosciences. 116: G03037.

Rohr, J.R.; Dobson, A.P.; Johnson, P.T.J. [et al.]. 2011. Frontiers in climate 

change-disease research. Trends in Ecology and Evolution. 26: 270–277.

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.

Ruediger, B.; Claar, J.; Gniadek, S. [et al.]. 2000. Canada lynx conservation 

assessment and strategy. R1-00-53. 2nd ed. Missoula, MT: U.S. Department of 

Agriculture, Forest Service; U.S. Department of the Interior, Fish and Wildlife 

Service, Bureau of Land Management, and National Park Service. 142 p. 
232

general technical report pnw-gtr-892

Schneider, S.H.; Root, T.L.; Van Putten, M. 2002. Wildlife responses to climate 

change: North American case studies. Washington, DC: Island Press. 350 p.

Schwartz, M.D.; Ahas, R.; Aasa, A. 2006. Onset of spring starting earlier across 

the Northern Hemisphere. Global Change Biology. 12: 343–351.

Schweiger, O.; Biesmeijer, J.C.; Bommarco, R. [et al.]. 2010. Multiple stressors 

on biotic interactions: how climate change and alien species interact to affect 

pollination. Biological Reviews. 85: 777–795.

Servheen, C. 1997. Grizzly bear recovery plan: North Cascades ecosystem 

recovery plan chapter. Supplement. Missoula, MT: U.S. Department of the 

Interior, Fish and Wildlife Service. 24 p.

Shoo, L.P.; 0lson, D.H.; McMenamin, S.K. [et al.]. 2011. Engineering a future for 

amphibians under climate change. Journal of Applied Ecology. 48: 487–492.

Simpson, W.G. 2009. American pikas inhabit low-elevation sites outside the 

species’ previously described bioclimatic envelope. Western North American 

Naturalist. 69: 243–250.

Smith, A.T. 1974. The distribution and dispersal of pikas: influences of behavior 

and climate. Ecology. 55: 1368–1376.

Smith, A.T. 1978. Comparative demography of pikas (Ochotona): effect of spatial 

and temporal age-specific mortality. Ecology. 59: 133–139.

Spies, T.A.; Hemstrom, M.A.; Youngblood, A.; Hummel, S. 2006. Conserving 

old-growth forest diversity in disturbance-prone landscapes. Conservation 

Biology. 20: 351–362.

Stebbins, R.C. 2003. A field guide to Western reptiles and amphibians. 3rd ed. New 

York: Houghton Mifflin Harcourt. 560 p.

Stralberg, D.; Jongsomjit, D.; Howell, C.A. [et al.]. 2009. Re-shuffling of

species with climate disruption: A no-analog future for California birds? 

PLoS ONE. 4: e6825. 

Stuart, S.N.; Chanson, J.S.; Cox, N.A. [et al.]. 2004. Status and trends of 

amphibian declines and extinctions worldwide. Science. 306: 1783–1786.

Thuiller, W.; Lavorel, S.; Araújo, M.B. [et al.]. 2005. Climate change threats to 

plant diversity in Europe. Proceedings of the National Academy of Sciences, 

USA. 102: 8245–8250.

Tiner, R.W. 2003. Geographically isolated wetlands of the United States. Wetlands. 

23: 494–516.
233

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Traill, L.W.; Lim, M.L.; Sodhi, N.S.; Bradshaw, C.J.A. 2010. Mechanisms 

driving change: altered species interactions and ecosystem function through 

global warming. Journal of Animal Ecology. 79: 937–947.

Tylianakis, J.M.; Didham, R.K.; Bascompte, J.; Wardle, D.A. 2008. Global 

change and species interactions in terrestrial ecosystems. Ecology Letters. 11: 

1351–1363.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2011. Proposed 

action for forest plan revision, Okanogan-Wenatchee National Forest. Portland, 

OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research 

Station. 89 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012a. Region 6 

terrestrial restoration and conservation strategy [TRACS]. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Region. 63 p.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2012b. The 

Okanogan-Wenatchee National Forest restoration strategy: adaptive ecosystem 

management to restore landscape resiliency. 2012 Version. Portland, OR: U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Region. 119 p.

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. Department of the Interior, National Park Service [USDI NPS]. 2006a.

Mountain lakes fishery management plan/EIS. http://parkplanning.nps.gov/

projectHome.cfm?projectID=10007. (9 April 2013).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2006b. 

Management policies: the guide to managing the National Park System. 

http://www.recpro.org/assets/Library/Agency_Recreation_Resources/nps_

policies2006. (9 April 2013).

Verlinden, M.; Nijs, I. 2010. Alien plant species favoured over congeneric natives 

under experimental climate warming in temperate Belgian climate. Biological 

Invasions. 12: 2777–2787.

Visser, M.E.; te Marvelde, L.; Lof, M.E. 2011. Adaptive phenological mismatches 

of birds and their food in a warming world. Journal of Ornithology. 153: 75–84.
234

general technical report pnw-gtr-892

Washington Wildlife Habitat Connectivity Working Group [WHCWG]. 2011.

Washington connected landscapes project: climate-gradient corridors report. 

Olympia, WA: Washington Department of Fish and Wildlife, Washington 

Department of Transportation. http://www.waconnected.org/wp-content/themes/

whcwg/docs/Final%20Climate%20Gradient%20Corridors%20Report%20

August%202011.pdf. (17 April 2013).

Wellborn, G.A.; Skelly, D.K.; Werner, E.E. 1996. Mechanisms creating 

community structure across a freshwater habitat gradient. Annual Review of 

Ecology and Systematics. 27: 337–363.

Williams, D.D. 2006. The biology of temporary waters. Oxford, United Kingdom: 

Oxford University Press. 337 p.

Willis, C.G.; Ruhfel, B.R.; Primack, R.B. [et al.]. 2010. Favorable climate 

change response explains nonnative species’ success in Thoreau’s Woods. 

PLoS ONE. 5: e8878.
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Introduction

The North Cascadia Adaptation Partnership (NCAP) held a 2-day workshop to 

assess vulnerability and adaptation options for the management of fish and fish 

habitat in the North Cascade Range (the area in Washington state from Mount 

Rainier north to the Canadian border). The workshop brought together regional 

scientists, fish biologists, and aquatic ecologists. Scientists from the University of 

Washington Climate Impacts Group, National Oceanic and Atmospheric Administration (NOAA) Northwest Fisheries Science Center, U.S. Department of Agriculture Forest Service (USDA FS) Pacific Northwest Research Station, Seattle City 

Light, and Tulalip Tribes presented the latest science on climate change effects on 

fish species and habitats. Fish biologists and aquatic ecologists from national forests 

and national parks in the NCAP presented an overview of current practices for fish 

management and aquatic habitat restoration. The goals of the workshop were to (1) 

identify the key sensitivities of fish and habitat to climate change, (2) review and 

share current management practices that increase resilience to climate change, (3) 

use the latest scientific information on climate change effects on fish to identify 

options for adapting management practices, and (4) identify opportunities to coordinate a regional approach to adaptation.

During the first day of the workshop, participants focused on four key sensitivities of fish and fish habitat: (1) higher flood frequency and magnitude of peak 

flows, (2) lower low streamflows, (3) warmer stream temperatures, and (4) higher 

sedimentation. Here we synthesize the latest scientific information on these sensitivities of fish and fish habitat based on information presented in the workshop, 

subsequent discussions with scientists and managers, and the scientific literature. 

The second day of the workshop focused on adaptation planning. After reviewing 

current practices for managing fish in the North Cascades, scientists and managers 

worked collaboratively to identify adaptations to these management practices to 

reduce detrimental effects associated with these sensitivities. Results of this adaptation planning effort are summarized below. 

1

 Nathan J. Mantua is a research scientist, National Oceanic and Atmospheric Administration, Southwest Fisheries Science Center, 3333 North Torrey Pines Court, La Jolla, CA 

92037; and Crystal L. Raymond is a climate change strategic advisor, City of Seattle, 

Seattle City Light, 700 5th Avenue, Seattle, WA 98124 (formerly a research biologist, U.S. 

Department of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific 

Wildland Fire Sciences Laboratory, Seattle, WA).

Chapter 7: Climate Change, Fish, and Fish Habitat in the 

North Cascade Range

Nathan J. Mantua and Crystal L. Raymond1
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Effects of Climate Change on Streamflows

Global climate model (GCM) simulations are typically used to project future 

climate for different greenhouse gas emission scenarios. In this assessment of the 

vulnerability of fish and fish habitat to climate change, we used future temperature 

and precipitation from monthly mean values generated from 10 GCMs under the 

A1B emission scenario and downscaled to the Pacific Northwest (PNW). See 

chapters 3 and 4 for more detail about these data and modeling approach. See box 

7.1 for a summary of data and tools used to assess the vulnerability of fish and fish 

habitat to climate change.

A warming climate, by itself, substantially affects the hydrology of watersheds 

in the North Cascade Range. Among the key hydrologic changes projected under all 

scenarios for the 2040s and beyond are a higher fraction of annual precipitation that 

Box 7.1—Key datasets and analysis tools that can be used to 

assess the vulnerability of fish and fish habitat in the North 

Cascades to climate change

•	 Comprehensive hydrologic data for long-range water planning in the 

Columbia River basin. Includes projections based on Intergovernmental 

Panel on Climate Change scenarios. Developed by the University of 

Washington Climate Impacts Group Access at http://www.hydro.washington.

edu/2860.

•	 Stream temperature data for the North Cascade Range. Includes simulated weekly average maximum stream temperatures for summer. Developed 

by University of Washington Climate Impacts Group (Mantua et al. 2010, 

Snover et al. 2010).

•	 Fine-scale monthly climate change data for the Pacific Northwest. Includes 

data for monthly meteorological forcings (precipitation, maximum temperature, minimum temperature) at 30 arc-seconds. Developed by University of 

Washington Climate Impacts Group (Mauger 2011). Access at http://cses.

washington.edu/data/met30s.shtml.

•	 Historical and projected future changes in soil water equivalent (SWE) 

for Oregon and Washington. Includes simulated SWE data at 30 arc-seconds. 

Developed by University of Washington Climate Impacts Group (Mauger 

2011). Access at http://cses.washington.edu/data/swe30s.shtml.

•	 Hydroclimate change projections for U.S. Forest Service lands in Oregon 

and Washington. Includes summaries for Bailey ecosections, Omernik level 

III ecoregions, and Hydrologic Unit Code (HUC) levels 4 and 5 basins. 

Developed by University of Washington Climate Impacts Group (Mauger 

2011). Access at http://cses.washington.edu/data/ USDA FS_orwa.shtml.

•	 NetMap community watershed database and tools. Includes data developed by users of NetMap and shared analysis tools. Developed by Benda 

et al. (2007). Access at http://www.netmaptools.org.
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falls as rain rather than snow, earlier snowmelt, lower springtime snowpack, higher 

runoff and streamflow in winter and early spring, lower runoff and streamflow in 

summer, an extended summer low-flow period, and overall reductions in summer 

streamflow. These trends are expected for monthly average flows and for streamflow extremes at a shorter time scale. In addition, substantial increases in high 

flows (e.g., 20-year return interval flows) are projected for autumn and winter, and 

substantial reductions in 7-day average summer low flows are projected for most 

locations in the North Cascades. 

Projected Changes in Streamflow Timing

Historical runoff in subbasins of the North Cascades can be classified as either 

snow dominant or transitional (meaning there are large contributions to cool season 

streamflow from both rain-fed and snowmelt runoff). Simulations of future runoff 

indicate a trend away from snow-fed runoff to more rain-fed runoff (Tohver et al., in 

press). By the 2080s, no snow-dominant subbasins will exist in the North Cascades, 

and most watersheds will be in the transitional classification (see chapter 4).

Simulated hydrographs for the Sauk River at Sauk, Washington, show the peak 

runoff in this basin to occur with snowmelt in May and June, whereas in the future, 

snowmelt runoff will be lower in late spring and early summer, and runoff will be 

higher in autumn, winter, and early spring (fig. 7.1). The period of annual low flows 

that historically occurred in September in the Sauk River may become a feature 

of August and September monthly average flows as early as the 2020s, and this 

kind of extended and amplified period of summer low flows could be common in 

most of the watersheds in the North Cascades (Tohver et al., in press) (see chapter 

4). The largest reductions in the lowest annual 7-day average flow with a recurrence interval of 2 years (7Q2) are projected for streams on the west slopes of the 

Cascades, although reductions of 20 to 40 percent are also widespread for streams 

on the east slopes of the Cascades in the 2040s and 2080s (fig. 7.2). Peak flows are 

also projected to increase substantially for many watersheds in the North Cascades 

(see chapter 4), and 20-year return interval flows are projected to increase 10 to 50 

percent for many watersheds for the 2040s, with even larger increases for the 2080s 

(fig. 7.3).

Projected Changes in Stream Temperature

Peak stream temperatures in summer have been modeled using nonlinear regressions between 7-day averages for observed stream and air temperatures, where 

historical stream temperature records are available (Mantua et al. 2010, Snover et 

al. 2010). Figure 7.4 shows historical and 2040s August air temperatures and annual 

maximum of weekly average water temperatures for select locations in Washington 
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Figure 7.1—Simulated hydrographs for the Sauk River near Sauk, Washington (U.S. Geological 

Survey gage 12189500). The x-axis shows a hydrologic year, from October (O) to September (S). The 

y-axis shows combined monthly average total runoff and baseflow over the entire basin expressed as 

average water depth (centimeters), a primary component of the simulated water balance and one of 

the primary determinants of streamflow. Blue lines show simulated historical values; light red bands 

show the range of different scenarios for the future time period and A1B emission scenario; dark red 

lines show the ensemble average scenario. From Climate Impacts Group (2010).
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Figure 7.2—Ratio of future to historical simulated low flow for the lowest annual 7-day average flow with a recurrence interval of 2 

years (7Q2), developed from and ensemble of 10 global climate model simulations under the A1B emission scenario. The left panel is for 

the 2020s, middle panel is for the 2040s, and right panel is for the 2080s. Figure adapted from Mantua et al. (2010) and data from Hamlet 

et al. (2010).

Figure 7.3—Ratio of future to historical simulated 20-year return interval flood statistics, from and ensemble of 10 global climate model 

simulations under the A1B emission scenario. The left panel is for the 2020s, middle panel is for the 2040s, and right panel is for the 

2080s. Figure adapted from Mantua et al. (2010) and data from Hamlet et al. (2010).
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under the multimodel climate change ensemble with the A1B scenario. A number of 

sites on the west slope of the North Cascades show warming that is large enough to 

move from “favorable” to “stressful” categories of thermal rearing habitats for 

salmonids, and a few sites remain within the favorable category (with annual 

maximum weekly average stream temperature below 17 °C under this scenario for 

the 2040s). 

Snover et al. (2010) applied the same stream temperature modeling approach 

to a different set of stream temperature records from the Skagit River basin (fig. 

7.5). Most modeled locations in the upper Skagit basin have projected temperatures 

remaining below 13 °C even for the 2080s, which is favorable for salmon and trout 

spawning and incubation, and all locations had projected temperatures below 17 °C 

in the 2080s, which is favorable for rearing habitat. These results suggest that some 

headwater streams in the North Cascades are likely to remain favorable cold-water 

habitat for salmonids even under significant warming in the 21st century.

Effects of Climate Change on Fish and Fish Habitat

Most salmon populations can respond favorably to altered habitat if changes are 

comparable to those experienced in the past (Waples et al. 2008). This refers 

primarily to disturbances that affect relatively small patches of habitat compared 

Figure 7.4—Color shading shows mean surface air temperatures for August, and shaded circles show 

the simulated mean of the annual maximum for weekly water temperatures (average, not transient) 

at select locations. Historical (1970–1999) reference period data are in the left panel, and the average 

future scenario for an ensemble of 10 global climate models under the A1B emissions scenario for 

the 2040s is shown in the right panel. The color scheme used here is tailored to three general categories for thermal rearing habitats for salmonids: greens indicate favorable, yellows indicate stressful, 

and reds indicate fatal. 

Many areas on the 

west slope of the 

North Cascades will 

be stressful for rearing 

habitats for salmonids.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

to the much larger spatial extent of evolutionarily significant population groups 

influenced by physiographic features. It is unknown if salmon populations in 

the North Cascades can adapt through phenological, phenotypic, or evolutionary 

mechanisms fast enough to survive a combination of climate change, altered habitat, and other stresses in the future (Crozier et al. 2008). However, it should be noted 

that genetic variants of some salmon species can in some cases adapt to changing 

Figure 7.5—August mean surface air temperature and maximum weekly average water temperatures 

for select locations in the Skagit River basin. The color scheme used here is tailored to three general 

categories for thermal rearing habitats for salmonids. For mean air temperature, greens indicate 

favorable, yellows indicate stressful, and reds indicate fatal. The color scheme for stream temperature 

is associated with criteria for salmonids: green indicates temperatures below 17 °C. 
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environmental conditions (Quinn and Unwin 1993), at least in the short term and if 

conditions are not extreme.

If salmon cannot adapt to rapidly changing habitat conditions, then higher 

stream temperature, altered streamflow, and other limiting factors will result in 

reduced quality and quantity of freshwater habitat (box 7.2). Effects on fish and fish 

habitats related to stream temperature, high flows, summer low flows, and sedimentation are summarized below. 

Stream Temperature

Water temperature is a key aspect of water quality for salmonids, and excessively 

high water temperature affects their distribution, migration, and health (Farrell et 

al. 2008, McCullough 1999, Richter and Kolmes 2005, U.S. Environmental Protection Agency [EPA] 2007). Excessively warm water can inhibit salmon migration 

and breeding patterns and reduce cold-water refugia and connectivity. When average water temperature is higher than 15 °C, salmon can suffer increased predation 

and competitive disadvantages with other native and nonnative warm-water fish 

(EPA 2007). Water temperatures higher than 21 to 22 °C can prevent migration 

(Goniea et al. 2006, High et al. 2006, Hyatt et al. 2003, McCullough 1999). Furthermore, adult salmon become more susceptible to disease and the transmission 

Box 7.2—Existing and emerging threats to fish and fish

habitat in the North Cascades 

• Reduced summer low flows, in some cases related to irrigation withdrawals, 

diminish and degrade available spawning habitat, rearing habitat, and migration corridors.

• Extreme peak flows scour redds while eggs are incubating.

• Invasive fish species perform better in warmer water and compete with or 

prey on native cold-water fish.

• Debris torrents are more frequent and intense in aggrading river channels.

• Floodplain connectivity is reduced, limiting off-channel habitats and habitat 

complexity that provide thermal buffers, thermal habitat diversity, and slowwater refugia from extreme high-flow events.

• Culverts, dams, natural falls, and logjams provide significant barriers to fish 

passage.

• Roads and related infrastructure, including hardened and engineered streambanks, degrade fish habitat.

• Maximum summer stream temperatures exceed key ecological thresholds for 

salmonids, contributing to adult migration barriers and increased susceptibility to pathogens.

Excessively high 

water temperature 

affects the distribution, 

migration, and health 

of salmonids.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

of pathogens in warmer water, and prolonged exposure to stream temperature above 

around 21 °C (although this varies by species) can be lethal for juveniles and adults 

(McCullough 1999). However, in some cases, adult salmon can migrate upstream 

through unfavorable temperatures by moving to areas with cool groundwater 

inputs, giving the impression that they tolerate high temperatures when in fact they 

are taking advantage of local thermal variation (Berman and Quinn 1991). Some 

species such as rearing coho (Oncorhynchus kisutch Walbaum) can tolerate stream 

temperatures as high as 29 °C for brief durations, as observed following the 1980 

eruption of Mount St. Helens, as long as food is plentiful (Bisson et al. 2005).

Stream temperature modeling projects significant increases in water temperature and thermal stress for salmon in portions of the North Cascades for both the 

A1B and B1 scenarios (Mantua et al. 2010, Snover et al. 2010). Projected water 

temperature patterns indicate there will be increases in the number of locations 

that are stressful for salmon in summer (where water temperature is higher than 

18 °C) (figs. 7.4 and 7.5). Summer air temperatures higher than 18 °C will become 

increasingly common for western Washington by the 2040s when only the higher 

elevations of the Cascades have surface air temperatures like those characteristic of 

the western Washington lowlands in the 1980s (figs. 7.4 and 7.5). 

Climate change is also projected to increase the frequency and persistence of 

thermal migration barriers and thermally stressed waters for salmon. Weeks with 

water temperature higher than 21 °C will increase considerably for the warmer 

streams in western Washington, such as the Stillaguamish River at Arlington, 

Washington, where in recent years these conditions existed for a maximum of a 

few weeks each summer. For this station, the period with water temperature higher 

than 21 °C persists up to 13 weeks by 2100 and is centered on the first week of 

August under the composite A1B scenario (Mantua et al. 2010) (fig. 7.6). The upper 

reaches of North Cascades watersheds are likely to remain much cooler than lower 

reaches (e.g., Stillaguamish River at Arlington). The lower reaches are typically key 

migration corridors for summer-running adult salmon on their spawning migration, 

indicating that thermal migration barriers and thermal stress will increase in at 

least some salmon populations in North Cascades watersheds with especially warm 

lower reaches.

Projected increases in water temperature will proceed at about an equal pace on 

both sides of the Cascade Range, although shifts to increasingly stressful thermal 

regimes for salmon will be highest for low elevations and the east side where the 

historic baseline for water temperatures are typically warmer than those at higher 

elevations. It is also likely that a warmer climate will reduce the availability of coldwater refugia in some North Cascades watersheds, although additional research 
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Figure 7.6—Simulated number of weeks each year that stream water temperature exceeds 21 °C (average, not transient) (top panel), and chronological 

weeks in each simulated year in which water temperature exceeds 21 °C (bottom panel) for the Stillaguamish River at Arlington, Washington. All points 

(historical and future) are from a simulation based on a regression between 

observed air temperature and the annual maximum of weekly average stream 

temperature, based on air temperature observations for 1916–2006, and the 

10-model average A1B emission scenario for 2007–2100. Historical simulations had no years with more than 3 weeks of water temperature higher than 

21 °C, but this thermal threshold is consistently exceeded starting in the 

2030s. Multiple points for a given year represent multiple weeks with water 

temperature higher than 21 °C. Week 30 is approximately the last week of 

July. From Mantua et al. (2010).
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

is needed to determine the spatial extent of this effect. The effects of glaciers, 

and their projected decrease in mass balance, on streamflow and temperature in 

different watersheds is poorly quantified, although one would expect that smaller, 

high-elevation streams in basins with significant coverage of glaciers would be 

more responsive to glacial meltwater than larger, low-elevation streams. Tributaries 

that face east have a higher contribution of glacial melt than west-facing streams 

(Snover et al. 2010) and may therefore be more sensitive to variation in glacial melt.

Limiting environmental factors differ for different stocks and species of 

Pacific salmon, which have a diversity of life history and habitat characteristics. 

For example, the most important factors for juvenile coho survival in freshwater 

are (1) in-stream temperature during the first summer, combined with the availability of deep pools to mitigate high temperatures, and (2) temperature during the 

second winter, combined with the availability of beaver (Castor canadensis Kuhl.) 

ponds and backwater pools to serve as refuges from cold temperatures and high 

streamflow (Beechie et al. 1994, Reeves et al. 1989). Consequently, a combination 

of higher summer water temperature, lower summer streamflow, and higher winter 

flows and will create unfavorable conditions for coho salmon.

The effects of warming streams will differ for different fish populations. Significant increases in stream temperature alone will create thermal stress for salmon 

populations that have a stream-type life history that puts them in freshwater during 

summer for spawning, rearing, spawning migrations, or seaward smolt migrations. 

In the absence of thermal cues for initiating spawning migrations, temperature 

effects on adult spawning migrations are projected to be most severe for stocks with 

summertime migrations. These stocks include summer-run steelhead (Oncorhynchus mykiss Walbaum), sockeye (O. nerka Walbaum), bull trout (Salvelinus 

confluentus Suckley), and summer chinook (O. tshawytscha Walbaum in Artedi) 

populations. Higher stream temperatures pose risks to the quality and quantity of 

favorable rearing habitat for stream-type chinook and coho salmon, steelhead (summer and winter run), and bull trout, because these stocks spend at least one summer 

(and for Washington steelhead typically two summers) rearing in freshwater. Lower 

summer and autumn low flows in transient and rainfall-dominated basins might 

also reduce the availability of spawning habitat for salmon and bull trout populations that spawn early in the autumn (e.g., Healey 1991).

Warmer water in streams in winter and spring may result in longer growing 

seasons for vegetation, increased productivity of aquatic food webs, and faster 

juvenile salmon growth and development in the freshwater life cycle (Beer and 

Anderson 2011, Schindler and Rogers 2009). It is possible that this could increase 

overall life-cycle productivity for some salmonids, such that positive effects 

Increased stream 

teperature will create 

thermal stress for 

salmon populations 

that have a stream-type 

life history.
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outweigh negative effects of climate change. For example, warmer stream temperatures benefited coho salmon adjacent to areas harvested for timber on Vancouver 

Island, British Columbia (Holtby 1988). Logging increased stream temperature 

(0.7 °C in December and over 3 °C in August), which in turn contributed to higher 

growth in juvenile coho, acceleration of its freshwater life history, and higher 

overwinter survival rates for rearing juveniles. However, these apparent benefits 

were balanced by reduced marine survival rates through earlier smolt migrations 

to the ocean that may have been mismatched with ocean prey and predator availability. Warmer stream temperatures increased the full life-cycle coho production 

in this system by approximately 9 percent (Holtby 1988). The potential for positive 

effects of stream warming is highest in the coldest streams, such as those found on 

the west side and at high elevations in the North Cascades.

Peak Streamflow

Seasonal and daily streamflow variations are limiting factors for freshwater salmon 

habitat (Beechie et al. 2006, Rand et al. 2006). For chinook salmon in the Skagit 

River, annual flood magnitude was a significant predictor of freshwater survival 

rates (larger floods caused lower survival rates) (Seiler et al. 2003) and total lifecycle return rates (Greene et al. 2005). These effects may be caused by several 

mechanisms linking peak incubation flows to early freshwater life-stage survival 

rates for salmon. Extreme flows during egg incubation periods can limit egg-to-fry 

survival rates by scouring redds, crushing eggs with mobilized gravels (De Vries 

1997, Holtby and Healy 1986, Montgomery et al. 1996), depositing fine sediments 

on redds that reduce available oxygen (Lotspeich and Everest 1981), and reducing 

populations of interstitial invertebrates. Peak flows can also reduce availability of 

slow-water habitats, which can flush rearing juveniles downstream from preferred 

habitats and subsequently reduce freshwater survival rates (Latterell et al. 1998).

Of all potential effects of climate change on the reproductive success of oceantype chinook salmon in the Snohomish River basin, projected increases in extreme 

high flows were the most damaging (Battin et al. 2007). Projected increases in 

the intensity and frequency of winter flooding in the transient runoff basins of the 

North Cascades will likely reduce egg-to-fry survival rates for pink (Oncorhynchus 

gorbuscha Walbaum), chum (O. keta Walbaum in Artedi), sockeye, chinook, and 

coho salmon because of increased intensity and frequency of redd and egg scouring. However, the effects of more winter flooding will likely differ across species 

and populations because redd depth is a function of fish size (deeper redds will be 
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less vulnerable to scouring and the deposition of fine sediments). Parr-to-smolt survival will likely decrease for coho and stream-type chinook salmon and steelhead 

because higher peak flows reduce availability of slow-water habitat and increase the 

displacement of rearing juveniles downstream, although in some cases, high flows 

may provide access to floodplain habitats that might not otherwise be accessible. 

Lower spring snowmelt may reduce smolt migrations from snowmelt dominant and 

transient streams in which seaward migration has evolved to match the timing of 

peak flows from snowmelt.

Summer Low Streamflow

Earlier snowmelt and higher evaporation in most North Cascades river basins will 

reduce streamflow in summer and early autumn, resulting in an extended period of 

summer low flows, and rainfall-dominant basins are projected to have substantially 

lower base flows. In combination with higher summer stream temperature, reduced 

summer flow will limit rearing habitat for salmon with stream-type life histories 

(in which juveniles rear in freshwater for one or more years) and increase mortality 

during spawning migrations for summer-run adults. 

Management of Fish and Fish Habitat in the North 

Cascades

The two national forests and two national parks in the NCAP manage for threatened fish species and naturally occurring riparian processes and aquatic habitat. 

Fish are managed under the direction of multiple federal, regional, and unit-level 

policies and guidelines. Many watersheds in the North Cascades provide critical 

habitat for anadromous fish species and bull trout listed under the federal Endangered Species Act (ESA) of 1973. Although management objectives for fish differ 

among the national forests and national parks based on agency mandates and past 

management, management on all four units focuses on recovering populations of 

listed anadromous fish and bull trout and protecting and restoring natural aquatic 

processes that create high-quality habitat for fish and other aquatic organisms. 

In the North Cascades, the USDA FS, the National Park Service (NPS), other 

resource management agencies, local utilities, municipal watersheds, watershed 

councils, and many tribes collaborate to manage fish populations concurrently with 

objectives for recreation, hydroelectric power generation, roads and infrastructure, 

and cultural resources. Current management reduces nonclimatic threats to fish 

populations including diseases, nonnative fish species, fish passage barriers, and 

adverse effects caused by roads, infrastructure, and recreation.

Earlier snowmelt and 

higher evaporation 

will reduce streamflow 

in summer and early 

autumn.
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Management of Fish and Fish Habitat on the Mount BakerSnoqualmie and Okanogan-Wenatchee National Forests

The Mount Baker-Snoqualmie National Forest (MBSNF) and Okanogen-Wenatchee 

National Forest (OWNF) manage for fish and aquatic habitat under the direction 

of the Northwest Forest Plan (NWFP) Aquatic Conservation Strategy (USDA and 

USDI 1994) and Pacific Northwest Region Aquatic Restoration Strategy (USDA 

FS 2005). Two additional plans apply to fish habitat in OWNF only—the Interim 

Strategy for Managing Anadromous Fish-Producing Watersheds in Eastern Oregon 

and Washington, Idaho and Portions of California (USDA and USDI 1995) and the 

Interim Strategy for Managing Fish-Producing Watersheds in Eastern Oregon and 

Washington, Idaho, Western Montana, and Portions of Nevada (USDA FS 1995). 

All of MBSNF and OWNF west and north of the Chewuch River are within the 

jurisdiction of the NWFP Aquatic Conservation Strategy. The objective of the plan 

is to prevent further degradation of aquatic habitat and restore and maintain aquatic 

process on USDA FS and Bureau of Land Management lands within the range of 

the northern spotted owl (Strix occidentalis caurina Merriam) (USDA and USDI 

1994). The long-term (100 years) goal of the strategy is to develop a network of 

functioning watersheds that can support populations of native fish and other aquatic 

organisms (Reeves et al. 2006). The aquatic conservation strategy achieves this 

goal through (1) watershed analysis, (2) riparian reserves with harvesting restricted 

to that necessary for desired vegetation conditions for aquatic habitat, (3) designation of key watersheds, (4) watershed restoration, and (5) standards and guidelines 

for management activities that could affect aquatic habitats. 

Management direction for fish and aquatic habitat in the portion of OWNF not 

covered by the NWFP is directed by the strategies PACFISH (USDA and USDI 

1995) and INFISH (USDA FS 1995). PACFISH provides direction for protecting 

and restoring watersheds in the western Pacific Northwest that support anadromous fish. INFISH provides direction for maintaining aquatic habitat for native 

fish species on national forest lands in the eastern PNW. The primary objective of 

these regional strategies is to maintain and restore aquatic habitat and protect listed 

fish species by reducing current threats associated with timber harvesting, roads, 

recreation, fish passage barriers, and loss of stream channel complexity. Although 

objectives of the regional strategies are similar, differences in terminology and 

requirements create a complex policy and regulatory environment for managing 

fish and aquatic habitat. 

Additional direction for managing fish and aquatic habitat in the national forests is provided by forest-specific land and resource management plans (e.g., forest 

plan). The OWNF forest plan (currently in revision) consolidates direction provided 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

by the multiple regional strategies into one common strategy for managing aquatic 

habitat. Direction for restoring aquatic habitats is also included in the forest restoration strategy. The goal of the forest plan and forest restoration strategy is to protect 

aquatic habitat by reducing existing threats and restoring habitat that has been 

adversely affected by past management, especially threats associated with roads. 

Managers identify roads and road segments with the highest impact on aquatic 

habitat based on hydrologic connectivity, fish distribution, slope and soil stability, 

and stream channel confinement. Site-specific restoration plans are developed, 

including several possible practices such as relocation, reconstruction, storm 

proofing, upsizing culverts, and road closure and decommissioning. The OWNF 

is currently taking the following actions to reduce current threats: (1) prioritizing 

roads for closure and decommissioning, (2) removing culverts to reduce sediment 

input, (3) modifying stream crossing surfaces, (4) installing drainage crossings, 

and (5) reducing storm damage. Human-caused confinement of stream channels is 

reduced by replacing culverts with bridges that span the active channel, relocating 

roads from active flood plains, upsizing stream crossings to reduce channel constriction, and reconstructing road segments that contain berms. Large woody debris 

are placed in and near streams to modify waterflow, provide habitat, and increase 

the complexity of stream channels where past management has reduced input of 

large woody debris. In addition to these actions to restore habitat, the OWNF coordinates with other state and federal agencies to manage fish species listed under 

ESA and participate in species-specific recovery plans. The OWNF is home to four 

federally listed threatened and endangered species, five species of concern, and 

critical habitat for two additional species. Management of aquatic habitat must meet 

objectives of the recovery plans for chinook salmon, steelhead, and bull trout in 

the Upper Columbia and Yakima River basins, and for bull trout in the Washington 

state recovery plan.

The MBSNF forest plan was amended by the NWFP aquatic conservation 

strategy in 1994, and a new forest plan has not been completed since then. Fish 

management focuses on (1) maintaining or improving aquatic and riparian areas 

with both active and passive restoration of watershed conditions and (2) protecting 

and restoring aquatic habitats for the benefit of fish resources. Managers on the 

MBSNF implement a range of actions to accomplish these goals with an emphasis 

on restoring natural aquatic processes. Fish biologists work with recreation specialists and engineers to reduce detrimental impacts to aquatic habitat associated with 

roads and trails. The MBSNF is completing a forestwide roads analysis and watershed analysis to identify priorities and locations for restoration. Ongoing inventories 

will evaluate baseline conditions, opportunities for restoration, and effectiveness of 
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restoration, including a survey of current road conditions and fish passage barriers. 

Managers work to restore aquatic habitat in partnership with other resource management agencies and tribes and collaborate on species-specific recovery plans.

Management of Fish and Fish Habitat at Mount Rainier and 

North Cascades National Parks

National Park Service management policies (USDI NPS 2006) direct park managers 

to preserve and restore native fish species by preserving and restoring the natural 

abundances, diversities, dynamics, and distributions of native populations; restoring 

native populations when they have been extirpated by past human-caused actions; 

and minimizing human impacts on native species, ecosystems, and the processes 

that sustain them. Native species are defined as species that “have occurred, now 

occur, or may occur as a result of natural processes” (USDI NPS 2006). Exotic 

species are those that occupy national park lands directly or indirectly as the result 

of human activities, and are not considered to be a natural component of the ecosystem. Native species are maintained primarily through natural processes, but active 

management is used when intervention will not cause unacceptable effects and is 

required to maintain populations affected by humans.

Park-specific general management plans (GMP) guide management of fish and 

aquatic habitat. The Mount Rainier National Park (MORA) GMP (USDI NPS 2001) 

directs managers to preserve or restore natural aquatic habitats and the natural 

abundance and distribution of native aquatic species, and provides the authority to 

manage exotic fish species when they threaten park resources or public health and 

when control is feasible. The park conserves all federally threatened and endangered species and their critical habitats. MORA is home to eight species of native 

fish, two of which are listed as threatened under ESA (1973) (chinook salmon and 

bull trout) and another two are proposed for listing (coho salmon and coastal cutthroat trout [O. clarkii clarkii Richardson]). Several rivers in the park are currently 

blocked to anadromous fish passage by dams outside park boundaries. Managers 

work collaboratively with other state, federal, local, and tribal resource management 

agencies to restore native resident and anadromous fish species.

Direction for management of fish and aquatic habitat at North Cascades 

National Park Complex (NOCA) is provided by the NOCA foundational statement 

and the GMPs of North Cascades National Park, Ross Lake National Recreation 

Area, and Lake Chelan National Recreation Area. Aquatic habitats are managed 

primarily by protecting ecological processes such as the natural movement of 

streams (stream meandering), rather than by managing for specific species or 

biophysical features. For example, the Stehekin River has changed course naturally 
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

over time in response to flooding and other river dynamics, thus, the management 

goal for the river is to maintain the natural movement of the channel whenever 

possible and to control river movements only where it is necessary to protect facilities or human health and safety. Individual species are managed only if they are 

classified as threatened or endangered. Park managers collaborate with NOAA, the 

U.S. Fish and Wildlife Service, and other agencies to ensure that listed species and 

their habitat are protected by actively participating in recovery plans. Managers also 

inventory and monitor listed species and critical habitat.

Most lakes in NOCA do not naturally contain fish, but many lakes have been 

stocked with exotic fish (salmonids) through a Washington Department of Fish and 

Wildlife (WDFW) program that maintains a recreational fishery. In 2009, NOCA 

developed the Mountain Lakes Fishery management plan (USDI NPS 2009) in 

coordination with WDFW in order to conserve native biological integrity while 

providing recreational fishing opportunities. Focused on 91 naturally fishless lakes, 

the plan includes authority and guidelines for removing reproducing populations of 

exotic fish that have achieved high densities, followed by monitoring the recovery 

of native species. Some lakes will continue to be stocked by WDFW with fish species that are not capable of reproduction.

Management of fish and aquatic habitat in the two recreational areas within 

NOCA emphasizes recreation associated with boating and fishing. Fishing is 

permitted in Ross Lake and Lake Chelan National Recreation Areas in accordance 

with federal and Washington state laws. Ross Lake is a popular fishing resort with 

a naturally reproducing fishery. In the recreational areas, fish management must 

balance the demands of recreation with preservation and protection of the fisheries 

resource. In addition to managing fisheries for recreation, the recreational areas 

also protect habitat for fish by protecting shoreline areas that provide spawning, feeding, and rearing habitats for fish, and support rare aquatic plant species. 

Managers have the authority to use occasional or seasonal closures of specific 

areas when drought or other conditions warrant additional resource protection. The 

recreational areas also preserve genetic resources by maintaining the abundance of 

unique populations to achieve desired levels of genetic variability.

Adapting Fish Management to Climate Change in the 

North Cascades

Many of the adaptation options identified in the workshop were similar to current 

practices for restoring fish habitat that are used in recovery plans for listed species 

because many of the listed species in the North Cascades are cold-water fish whose 

habitat is likely to be affected by warmer stream temperatures. In addition, many 
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of the adaptation strategies that focus on increasing resilience of fish habitat to 

changes in climate also increase resilience to habitat fragmentation, habitat loss, 

and migration barriers. Some adaptation strategies overlap with those identified for 

other resource sectors; for example, strategies that address impacts on fish habitat 

that are exacerbated by roads (higher peak flows and sedimentation) are similar to 

adaptation strategies identified for reducing impacts of higher peak flows on access 

and infrastructure (table 7.1) (see chapter 4).

Adaptation Options to Reduce Effects of High Peak Streamflows 

Climate change may motivate managers to alter practices for managing fish and 

restoring aquatic habitats to account for increased frequency and magnitude of 

peak streamflows. Higher peak flows will affect multiple life stages including egg 

incubation, stream rearing, and river entry of fall spawning salmon and steelhead 

(Mantua et al. 2010). One adaptation strategy to increase resilience of fish populations is to improve habitat quality and increase spawning habitat for fall-spawning 

salmon and overwintering populations by restoring natural hydrologic processes 

and flood plain dynamics (table 7.2). Removing natural or artificial barriers to 

fish migration can directly increase spawning habitat (Beechie et al. 2012). Efforts 

to survey and map alternative spawning habitat that will be robust to higher 

peak flows will facilitate protection of spawning habitat in a changing climate. 

Resilience can also be increased by restoring the natural complexity of the stream 

channel and flood plain enabling stream channels to buffer the effects of high peak 

flows. For example, engineered logjams are a means for directing streamflow and 

protecting infrastructure without the use of artificial flood control structures that 

may negatively affect downstream fish habitat.

Roads and infrastructure in the floodplain exacerbate the effects of higher 

peak flows on aquatic habitats by increasing runoff and contributing to the flashiness of floods. Higher peak flows in winter will challenge current efforts to balance restoration of fish habitat and protection of infrastructure in the floodplain. 

Climate change may increase the desirability of restoring natural floodplains and 

hydrological processes by disconnecting roads from streams, reducing road density, 

removing infrastructure, and increasing the capacity of culverts and other stream 

crossing structures. Managers in the North Cascades are already working to restore 

natural floodplain processes. The minimum roads analysis, a process underway at 

each national forest, is designed to identify and manage a sustainable road network. 

One criterion used to determine which roads should be closed or decommissioned 

is the risk posed by road segments to aquatic habitat. Increases in peak flows will 

be especially high in mixed rain-and-snow basins where more winter precipitation 

Many adaptation 

strategies also 

increase resilience to 

habitat fragmentation, 

habitat loss, and 

migration barriers.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 7.1—Summary of restoration actions and their ability to ameliorate climate change effects, and to 

increase the resilience of salmon populations

Category Common techniques

Ameliorates 

temperature 

increase a

Ameliorates 

base flow

decrease

Ameliorates 

peak flow

increase

Increases 

salmon 

resilience

Longitudinal connectivity 

(barrier removal)

Removal or breaching of dam

Barrier or culvert replacement/

removal

+

0

+

0

0

0

+

+

Lateral connectivity 

(flood plain reconnection)

Levee removal

Reconnection of flood plain

features (e.g., channels, ponds)

Creation of new flood plain

habitats

+

+

+

0

0

0

+

+

+

+

+

+

Vertical connectivity 

(incised channel 

restoration)

Reintroduce beaver (dams increase 

sediment storage)

+ + + +

Remove cattle (restored vegetation 

stores sediment)

+ + + 0

Install grade controls + + + 0

Streamflow regimes Restoration of natural flood regime + + 0 C

Reduce water withdrawals, restore 

summer baseflow

+ + 0 0

Reduce upland grazing 0 C C 0

Disconnect road drainage from 

streams

0 0 + 0

Natural drainage systems, retention 

ponds, other urban stormwater 

techniques

0 C + 0

Erosion and sediment 

delivery

Road resurfacing 0 0 0 0

Landslide hazard reduction (sidecast removal, fill removal)0 0 0 0

Reduced cropland erosion (e.g., 

no-till seeding)

0 0 0 0

Reduced grazing (e.g., fencing 

livestock away from streams

C 0 0 0

Riparian functions Grazing removal, fencing, 

controlled grazing

+ 0 0 0

Planting (trees, other vegetation) + 0 0 0

Thinning or removal of understory 0 0 0 0

Remove nonnative plants C C 0 0
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Category Common techniques

Ameliorates 

temperature 

increase a

Ameliorates 

base flow

decrease

Ameliorates 

peak flow

increase

Increases 

salmon 

resilience

Instream rehabilitation Re-meandering of straightened 

stream, channel realignment

C 0 0 C

Addition of log structures, logjams C 0 0 0

Boulder weirs and boulders C 0 0 0

Brush bundles, cover structures 0 0 0 0

Gravel addition 0 0 0 0

Nutrient enrichment Addition of organic and inorganic 

nutrients

0 0 0 0

a

 Actions are grouped by major processes or functions they attempt to restore. Effects are positive (+), none (0), or context-dependent (C). From 

Beechie et al. (2012).

Table 7.1—Summary of restoration actions and their ability to ameliorate climate change effects, and to 

increase the resilience of salmon populations (continued)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Table 7.2—Climate change sensitivities of fish and aquatic habitat to increased flood frequency and magnitude in autumn and winter; adaptation strategies and tactics to reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Increased flood frequency and higher peak flows may reduce egg-fry survival for fall spawners and yearling parr winter survival. 

Strategy: Increase spawning habitat resilience by restoring stream and flood-plain structure and

processes.

• Restore stream and flood-plain complexity• Increase protection of alternative spawning 

habitat

• Consider removing natural barriers to increase 

spawning habitat

• Increase use of engineered logjams where

feasible

Listed species increase opportunities for funding and management Actions can be restricted in habitat for listed species Identify and map alternative spawning locations

Strategy: Increase habitat resilience by reducing threats from roads and infrastructure in the flood plain.

• Designate and restore natural flood plain

boundaries 

• Increase flood-plain habitat• Remove infrastructure from flood plains• Disconnect roads from streams• Reduce road density near streams• Increase culvert capacity• Reduce flashiness of peak flows

USDA Forest Service minimum roads analysis is an opportunity to identify roads that present high risks to aquatic habitatNational Park Service General Management Plan direction to remove infrastructure from the flood plainCoordinate with partners through regional transportation planning

Constraints on closing roads because of access needs and historic landmark designationsConstraints on relocating roads owing to wilderness boundaries 
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will fall as rain rather than snow. Thus, it may be necessary to reevaluate the risks 

of roads on aquatic habitat in these mixed rain-and-snow basins. National parks in 

the NCAP are responding to current flood threats to aquatic habitat by mitigating 

the impacts of roads and infrastructure in the floodplain, although mitigation must 

consider the historical landmark designation of some roads and needs for access. 

Higher peak flows will challenge current efforts to protect listed fish species 

in the North Cascades. The presence of listed species restricts the types of actions 

that can be used to restore floodplain processes. Given projected increases in peak 

flows, it will be helpful to reevaluate the potential benefits of long-term restoration 

efforts in aquatic ecosystems versus detrimental short-term effects on species. The 

presence of listed species can also create opportunities for increasing political and 

public support and funding for adaptation.

Adaptation Options to Reduce Effects of Lower Low Streamflows

Reduced streamflow in summer and extended periods of low flow will likely 

require additional measures to protect rearing habitat for salmon with stream-type 

life histories and spawning habitat for summer-run steelhead (table 7.3) (Mantua 

et al. 2010). Lower summer flows will be most pronounced in rain-dominated and 

mixed rain-and-snow basins that have less spring runoff from snowpack (Elsner 

et al. 2010). Adapting fish management practices to mitigate the impacts of lower 

summer flows may require shifting habitat restoration priorities to off-channel 

habitats or to channels that are fed by wetlands because these channels typically 

maintain higher summer flows and will be important habitat for life stages sensitive 

to the magnitude of summer flows. 

Mapping off-channel habitats, wetland-fed streams, and significant springs to 

prioritize habitats for protection and restoration will be useful, particularly where 

projects are planned to protect infrastructure from flooding that alter waterflow 

from wetlands to streams. Restoring mid- and high-elevation wetlands where 

hydrology has been altered by past management can increase water storage and runoff to streams during low flow periods in summer (Beechie et al. 2012). Increasing 

forest cover at mid to high elevations, areas most susceptible to decreasing snow, 

may help retain snowpack later in spring and increase fog interception (Harr 1982). 

However, higher forest cover could increase evapotranspiration in summer and 

decrease runoff and introduce tradeoffs with managing lower density vegetation 

to increase resilience to drought and disturbance (see chapter 5). These changes in 

restoration priorities can be incorporated into existing vegetation and aquatic restoration projects and strategies. Although funding for restoration is limited, it may be 

feasible to initially focus on small projects for which funding may be available.

Adapting fish 

management to 

mitigate for lower 

summer flows may 

require shifting 

restoration priorities to 

off-channel habitats.
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Table 7.3—Climate change sensitivities of fish and aquatic habitat to lower low streamflow; adaptation strategies and tacticsto reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Lower low flows will reduce fish habitat quality.

Strategy: Increase aquatic habitat resilience to low summer flows. 

• Increase off-channel habitat and protect 

refugia in side channels and channels fed by wetlands 

• Protect wetland-fed streams which maintain 

higher summer flows

Existing aquatic habitat restoration plans

Insufficient funding Inventory current wetland-fed 

streams and wetland habitatsMap off-channel habitat, especially where infrastructure protection projects are planned

Strategy: Manage upland vegetation to retain water and snow in order to slow spring snowmelt and runoff. 

• Increase forest cover to retain snow and decrease snow melt

• Restore mid- and high-elevation wetlands that 

have been altered by past management

Incorporate adaptation into current vegetation restoration programs and plansSmall restoration projects are more likely to be funded

Sensitivity: Lower low flows will increase pre-spawn mortality for summer run and stream-type salmon and steelhead. 

Strategy: Increase in-stream flows with dry-season

water conservation to reduce withdrawals.

• Increase efficiency of irrigation techniques• Reduce summer withdrawals on U.S. Department of Agriculture Forest Service (USDA FS) 

and National Park Service (NPS) lands

• Consider alternative water supplies for USDA 

FS and NPS operations to retain in-stream flows

• Coordinate with downstream partners on water 

conservation education

Coordination with watershed planning groupsCoordination with municipal and private water suppliers to increase water conservation efforts
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Climate change may require changes in water use and additional conservation 

measures to maintain in-stream flows and mitigate the effects of reduced summer flows on fish habitat (Beechie et al. 2012). Managing for in-stream flows will 

need to be balanced with demand for multiple uses of water during the dry season 

(Mantua et al. 2010). Although most withdrawals and water use for irrigation occur 

outside of federal boundaries, national forests and national parks in the NCAP do 

withdraw water for some operations. During seasonal low flows and years that are 

drier than average, water availability can be enhanced by reducing water use and 

withdrawals for facilities, operations, and recreation, as well as considering alternative water supplies. Coordinating with adjacent landowners, municipal and private 

water suppliers, watershed planning groups, and downstream water users will 

provide opportunities to increase water conservation and mitigate the impact of low 

streamflows. 

Adaptation Options to Reduce Effects of Warmer Stream 

Temperatures

Warmer water temperatures associated with warmer air temperatures and lower 

low flows will increase thermal stress on cold-water fish and require additional 

actions to protect and restore fish populations and habitat for spawning (Mantua et 

al. 2010). Protecting and increasing cold-water refugia in side channels, particularly 

those that are fed by wetlands, can create more habitat for fish when temperatures 

are high in the wider main channels. Streams fed by wetlands can have higher 

low flows during the dry season and contribute colder water to the side and main 

channels (table 7.4). Additional actions to increase resilience of spawning habitat to 

warmer temperatures include reconnecting floodplains, restoring natural structure 

and heterogeneity of stream channels, and removing dikes and levees to restore 

natural streamflows that can buffer against warming temperatures (Beechie et al. 

2012). Restoring riparian vegetation where it has been reduced or removed can 

increase shading of streams and may also help maintain cooler water temperatures 

(Beechie et al. 2012).

Existing aquatic restoration strategies and species-specific recovery plans 

provide an opportunity to implement actions to mitigate the impacts of warmer 

stream temperatures. Many of the actions for increasing resilience to warmer 

stream temperatures are similar to actions taken as part of existing restoration plans 

to reduce nonclimatic threats. Existing roads and other infrastructure in the floodplain affect natural hydrologic processes and functions in some areas, and roads 

and infrastructure damaged by floods provide an opportunity for restoring natural 

hydrologic processes and floodplains. Climate change creates a new context in 

Climate change may 

require changes 

in water use and 

additional conservation 

measures to maintain 

in-stream flows.
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Table 7.4—Climate change sensitivities of fish and aquatic habitat to warmer stream temperatures; adaptation strategies and tactics to reduce impactsAdaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Warmer stream temperatures will reduce thermal heterogeneity in streams and increase thermal stress on summer run and stream-type salmon and steelhead.

Strategy: Increase habitat resilience for coldwater fish by restoring structure and function

of streams.

• Increase habitat and refugia in side

channels

• Protect wetland-fed streams which maintain higher summer flows• Restore structure and heterogeneity of 

stream channels

• Reconnect floodplains • Remove dikes and levees• Restore and protect riparian vegetation

Aquatic habitat restoration plansRoads or infrastructures that have been damaged by floods are opportunities to restore natural processes

Insuffecient fundingPrivate property encroachment and existing infrastructure in the flood plain

Inventory current wetland-fed streams and wetland habitatsMap off-channel habitat, especially in areas where infrastructure protection is plannedA better understanding of natural floodplain processes

Strategy: Increase understanding of thermal tolerances of fish species. 

• Conduct field experiments of fish-temperature relationships for multiple species 

and regions

• Monitor changes in stream temperature 

fish distributions

• Reevaluate and update water temperature 

standards (both values and indices)

Collaboration with Environmental Protection Agency (EPA) on water temperature standards

Field-based information on fish-temperature relationships
260

general technical report pnw-gtr-892 Adaptation tactics Opportunities for implementation Barriers to implementation Information needs Strategy: Increase understanding of thermal heterogeneity in streams and cold-water refugia. • Identify and inventory cold water refugia, springs, and groundwater input to streams • Identify seasonal refugia (winter and summer) • Research the influence of lakes, res- ervoirs, and groundwater on stream temperatures • Research fish use of thermal refugia Temperature monitoring technology is improving and cost is declining Coordination among agencies (e.g., Bonneville Power Administration and law enforcement agencies) to make use of technology not being used

Sensitivity: Warmer stream temperatures may favor nonnative fish species.

Strategy: Increase resilience of native fish

species by reducing barriers to native species and removing nonnative species. 

• Survey and map nonnative species• Combine nonnative mapping with information on migration barriers

• Consider information from surveys of 

warmer basins farther south as indicators of vulnerability

• Remove or control nonnative fish species• Assess migration barriers and potential 

habitat for native species 

• Remove barriers to fish passage where 

this will not increase threats from nonnative species 

• Maintain or construct barriers to prevent 

spread of nonnative species

Current National Park Service and U.S. Department of Agriculture Forest Service (USDA FS) programs for control and removal of nonnative speciesExisting USDA FS stream surveys Share survey data among partners (e.g., Seattle City Light, Washington Department of Fish and Wildlife)Stamp fees for warm-water fish with fees applied to removal and control effortsExisting databases such as the Salmon and Steelhead Habitat Inventory and Analysis Project and Net MapGeneral public support for removal of nonnative species

Funding for nonnative removal efforts Tradeoffs between migration barriers for nonnative species and barriers for native species Opposition from the recreational fishing community to removal of nonnative species A lack of warm-water fishery markets

Limitations of current surveys: cover only areas upstream to anadromous fish barriers and focus on only one or two species

Table 7.4—Climate change sensitivities of fish and aquatic habitat to warmer stream temperatures; adaptation strategies and tactics to reduce impacts (continued)
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Adaptation tactics Opportunities for implementation Barriers to implementation Information needsSensitivity: Warmer stream temperatures may create more favorable conditions for diseases and parasites. 

Strategy: Increase population resilience by increasing fish health.

• Increase public education to eliminate 

disease vectors

• Direct treatment or removal of infected 

fish

• Survey fish health conditions • Collaborate and standardize health survey 

methods among agencies 

• Consider changes in hatchery practices

Collaboration with hatcheries to collect information on disease transmission rates USDA FS Wild Fish Health Survey program

Lack of standardization for previously collected data collection

Research on relationships among stream temperature, thermal stress, and fish health in the natural environment.

Sensitivity: Warmer summer stream temperatures may alter aquatic food webs.

Strategy: Monitor changes in aquatic food web dynamics. 

• Assess food webs for baseline data • Monitor food web dynamics for changes 

with warming

Aquatic and Riparian Effectiveness Monitoring Plan and EPA Environmental Monitoring and Assessment Program studies of amphibians, fish, invertebrates and temperature dataResearch collaborations with state agencies and universitiesCollaboration with scientists studying effects of agricultural chemicals on aquatic food webs

Previous research has focuses on small streams Lack of information on nongame species that are important to the food web No central clearinghouse for data on aquatic food webs

Information on food web dynamics in larger streams and rivers

Table 7.4—Climate change sensitivities of fish and aquatic habitat to warmer stream temperatures; adaptation strategies and tactics to reduce impacts (continued)
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which to evaluate the objectives of current restoration plans relative to projections 

for higher stream temperature. Some locations and fish stocks may become more 

difficult to protect and maintaining all species in all locations will not be possible 

(Lawler 2009), making it advisable to prioritize and allocate resources for restoration accordingly (Beechie et al. 2008a).

Additional research on temperature tolerances of fish and thermal heterogeneity 

in streams will provide critical information to increase the effectiveness of strategies for adapting fish management and restoration to a warmer climate. Field-based 

experiments can increase scientific understanding of temperature relationships for 

multiple fish species and life histories and among different geographical regions. As 

stream temperatures warm, it will be important to monitor changes in fish distributions to determine priority areas for restoration and inform where restoration will 

be feasible and effective in a warmer climate. Monitoring and research will also be 

important for informing policies on water temperature standards. National forests 

and national parks in the NCAP can work collaboratively with the U.S. Environmental Protection Agency to determine appropriate water temperature standards. 

It will be important to increase understanding of thermal regimes of streams and 

to identify microhabitats such as cold water refugia and locations of ground water 

input and how fish use these microhabitats. Coordination among agencies in the 

North Cascades can optimize resources available for these research and monitoring 

needs. 

Warmer stream temperatures may favor nonnative species that typically tolerate 

a wider range of stream temperatures. One adaptation strategy is to increase the 

resilience of native fish species by reducing barriers to fish migration and removing 

nonnative fish. Removing barriers to native fish migration must be balanced with 

the potential to increase the distribution of nonnative species. Additional monitoring is needed to assess barriers to native fish migration and where these barriers 

can be removed to increase native fish migration without increasing nonnative fish 

migration. Existing fish surveys and monitoring programs can be leveraged for this 

assessment. Where appropriate, exotic fish species can be removed or barriers can 

be constructed to prevent the movement of these species. The current nonnative fish 

removal program at NOCA is already removing nonnative species, although adaptation efforts like this one may be met with opposition from user groups. It would 

also be valuable to evaluate data from watersheds in the southern Cascades that 

may indicate how native and nonnative fish species interact in warmer lakes and 

streams. Multiple agencies in the North Cascades currently survey native and nonnative fish. Increased coordination and data sharing will improve efforts to adapt 

Warmer stream 

temperatures may 

favor nonnative 

species that typically 

tolerate a wider 

range of stream 

temperatures.
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

fish management in a changing climate by providing a broad spatial perspective for 

data collection, restoration strategies, and optimal allocation of limited resources 

for active management. 

Warmer water temperatures may create more favorable conditions for diseases 

and parasites, making fish health a higher priority. Resilience to diseases and 

parasites can be improved by certifying that hatchery outplantings are disease-free 

and increasing public education to eliminate pathways for the spread of diseases. 

Increasing population resilience by protecting fish health will require collaboration 

among multiple agencies which can coordinate monitoring, standardize methodologies, and increase data sharing on disease spread. Working with hatchery managers 

may also be important for altering hatchery practices that contribute to the spread 

of diseases and parasites. 

Warmer water temperatures in cool seasons may increase productivity and 

alter aquatic food webs. Baseline conditions can be established by understanding 

current food web dynamics and monitoring how these dynamics change as water 

temperatures warm. Several opportunities exist for coordinating between agencies and universities to increase data and understand aquatic food webs. Previous 

research has generally focused on only small streams and not provided information 

on nonharvested species, which are also critical to aquatic ecosystems. Increasing 

efforts to share these data among agencies will facilitate planning for restoration 

and adaptation. 

Adaptation Options to Reduce Effects of Sedimentation

Increased sedimentation in streams may be a significant stress on fish habitat 

in some locations. Climate change is likely to increase sediment input from (1) 

more frequent and severe flooding of roads and culverts, (2) receding glaciers and 

exposure of loose moraine debris, and (3) erosion from wildfires that are likely to 

burn more area and reduce vegetation cover (Littell et al. 2010). This may make it 

necessary to increase efforts and reassess priorities for replacing culverts, decommissioning roads, and relocating roads away from stream channels (table 7.5). 

Several current assessments and projects in NCAP national forests and national 

parks are opportunities to alter sediment dynamics in road management, including the minimum roads analysis currently underway in both national forests and 

current road restoration projects in the Stehekin Valley (NOCA) and Carbon River 

areas (MORA) (see chapter 4). Many adaptation strategies and tactics for reducing 

the vulnerability of fish to climate change are similar to those for reducing threats 

to access and infrastructure (see chapter 4). These strategies can be explored for 

their combined benefits and potential “win-win” outcomes.
264

general technical report pnw-gtr-892 Table 7.5—Sensitivities of fish habitat to increased sedimentation; adaptation strategies and tactics to reduce impacts Adaptation tactics Opportunities for implementation Barriers to implementation Information needs Sensitivity: Increased sedimentation in streams with increased flooding of roads and culverts. 

Strategy: Manage and reduce sediment generated by roads. 

• Evaluate road system for sediment input

• Reduce sediment input to streams 

by replacing culverts, and relocating and decommissioning roads

U.S. Department of Agriculture Forest Service (USDA FS) minimum roads analysisCurrent National Park Service (NPS) road replacement and restoration projects (e.g., Stehekin Valley and Carbon River roads)

Sensitivity: Increased sedimentation in streams from erosion with increases in fire area and fire severity. 

Strategy: Reduce sedimentation associated with erosion and fire. 

• Include climate change projections in identification of potential 

areas for stream bank and upland erosion

• Inventory disturbed areas for 

candidate sites for riparian and upland vegetation restoration

• Manage fire and fuels with thinning and prescribed fire to reduce 

fire severity and extent

Ongoing NPS and USDA FS restoration projects (e.g., Stehekin River riparian restoration)Okanogan-Wenatchee National Forest Restoration StrategyCollaboration with river councils to restore and protect entire watershedsPartnerships with Burned Area Emergency Response for funding of postfire erosion control

Identify locations that are likely to be vulnerable to increased erosion
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Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Increased area burned and more high-severity fire combined with higher 

winter rainfall will probably increase erosion of soil particles into streams. Projections of altered fire regimes and hydrologic regimes can be incorporated into the 

prioritization of locations for streambank stabilization and upland erosion control. 

Increased monitoring of burned areas for erosive potential will help identify areas 

where mitigation activities could prevent erosion. Current road restoration strategies provide opportunities to plan for the interacting effects of climate change, fire, 

and erosion on fish habitat. Complementary adaptation strategies for increasing 

vegetation resilience to disturbance, such as prescribed fire and fuel treatments, 

can reduce fire severity and erosion potential after fire. Interdisciplinary efforts 

that consider restoration of terrestrial and aquatic components of ecosystems are 

likely to have the greatest benefit for increasing resilience of fish and fish habitat to 

climate change.

Acknowledgments

We thank members of the natural resource staffs at Mount Baker-Snoqualmie 

National Forest, Okanogan-Wenatchee National Forest, North Cascades National 

Park Complex, and Mount Rainier National Park for their expertise and input 

during workshops and subsequent discussions, including Barbara Samora, Ashley 

Rawhouser, Loren Everest, Amy Leib, and Emily Johnson. Pete Bisson and Loren 

Everest provided helpful reviews of this chapter. We also thank several regional 

experts for their contributions to the fish workshop including Ed Conner, Kit 

Rawson, Pete Bisson, Christian Torgerson, Karl Polivka, and Tim Beechie. 

Literature Cited

Battin, J.; Wiley, M.W.; Ruckelshaus, M.H. [et al.]. 2007. Projected impacts 

of climate change on salmon habitat restoration. Proceedings of the National 

Academy of Sciences of the United States of America. 104: 6720–6725.

Beechie, T.; Imaki, H.; Greene, J. [et al.]. 2012. Restoring salmon habitat for a 

changing climate. River Research and Applications. doi: 10.1002/rra.2590.

Beechie T.; Pess G.; Roni, P.; Giannico, G. 2008a. Setting river restoration 

priorities: a review of approaches and a general protocol for identifying and 

prioritizing actions. North American Journal of Fisheries Management. 28: 

891–905.

Beechie, T.J.; Beamer, E.; Wasserman, L. 1994. Estimating coho salmon rearing 

habitat and smolt production losses in a large river basin, and implications for 

habitat restoration. North American Journal of Fish Management. 14: 797–811.

Road restoration 

strategies provide 

opportunities to plan 

for the interacting 

effects of climate 

change, fire, and 

erosion on fish habitat.
266

general technical report pnw-gtr-892

Beechie, T.J.; Buhle, E.; Ruckelshaus, M. [et al.]. 2006. Hydrologic regime and 

the conservation of salmon life history diversity. Biological Conservation. 130: 

560–572.

Beer, W.N.; Anderson, J.J. 2011. Sensitivity of juvenile salmonid growth to future 

climate trends. River Research and Applications. 27: 663–669.

Benda, L.E.; Miller, D.J.; Miller, K. [et al.]. 2007. NetMap: a new tool in support 

of watershed science and resource management. Forest Science. 53: 206–219.

Berman, C.; Quinn, T.P. 1991. Behavioural thermoregulation and homing by 

spring chinook salmon, Oncorhynchus tshawytscha Walbaum, in the Yakima 

River. Journal of Fish Biology. 39: 301–312.

Bisson, P.A.; Crissafulli, C.M.; Fransen, B.R. [et al.]. 2005. Responses of fish to 

the 1980 eruption of Mount St. Helens. In: Dale, V.H.; Swanson, F.R.; Crisafulli, 

C.M., eds. Ecological responses to the 1980 eruption of Mount St. Helens. New 

York, NY: Springer: 163–182.

Climate Impacts Group [CIG]. 2010. Site-specific data, Sauk River near

Sauk. http://www.hydro.washington.edu/2860/products/sites/?site=6020.

(9 November 2012).

Crozier, L.G.; Zabel, R.W.; Hamlet, A. 2008. Predicting differential effects of 

climate change at the population level with life-cycle models of spring chinook 

salmon. Global Change Biology. 14: 236–249.

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.

Endangered Species Act of 1973 [ESA]. 16 U.S.C. 1531–1536, 1538–1540.

Farrell, A.P.; Hinch, S.G.; Cooke, S.J. [et al.]. 2008. Pacific salmon in hot

water: applying aerobic scope models and biotelemetry to predict the success 

of spawning migrations. Physiological and Biochemical Zoology. 81: 697–708.

Goniea, T.M.; Keefer, M.L.; Bjornn, T.C. [et al.]. 2006. Behavioral 

thermoregulation and slowed migration by adult fall chinook salmon in response 

to high Columbia River water temperatures. Transactions of the American 

Fisheries Society. 135: 408–419. 
267

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Greene, C.M.; Jensen, D.W.; Beamer, E. [et al.]. 2005. Effects of environmental 

conditions during stream, estuary, and ocean residency on chinook salmon 

return rates in the Skagit River, Washington. Transactions of the American 

Fisheries Society. 134: 1562–1581. 

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. In: Final report for the Columbia 

Basin climate change scenarios project. Seattle, WA: University of Washington, 

Center for Science in the Earth System, Joint Institute for the Study of the 

Atmosphere and Ocean, Climate Impacts Group. 27 p. Chapter 4.

Harr, R.D. 1982. Fog drip in the Bull Run municipal watershed, Oregon. Water 

Resources Bulletin. 18: 785–789.

Healey, M.C. 1991. Life history of chinook salmon (Oncorhynchus tshawytscha). 

In: Groot, C.; Margolis, L., eds. Pacific salmon life histories. Vancouver, BC: 

University of British Columbia Press: 313–393.

High, B.; Perry, C.A.; Bennett, D.H. 2006. Temporary staging of Columbia 

River summer steelhead in cool-water areas and its effect on migration rates. 

Transactions of the American Fisheries Society. 135: 519–528.

Holtby, L.B. 1988. Effects of logging on stream temperatures in Carnation Creek, 

British Columbia, and associated impacts on the coho salmon (Oncorhynchus 

kisutch). Canadian Journal of Fisheries and Aquatic Sciences. 45: 502–515.

Holtby, L.B.; Healey, M.C. 1986. Selection for adult size in female coho salmon 

(Oncorhynchus kisutch). Canadian Journal of Fisheries and Aquatic Sciences. 43: 

1946–1959.

Hyatt, K.D.; Stockwell, M.M.; Rankin, D.P. 2003. Impact and adaptation 

responses of Okanagan River sockeye salmon (Oncorhynchus nerka) to climate 

variation and change effects during freshwater migration: stock restoration and 

fisheries management implications. Canadian Water Resources Journal. 28: 

689–713.

Latterell, J.L.; Fausch, K.D.; Gowan, C.; Riley, S.C. 1998. Relationship of trout 

recruitment to snowmelt runoff flows and adult trout abundance in six Colorado 

mountain streams. Rivers. 6: 240–250. 

Lawler, J.J. 2009. Climate change adaptation strategies for resource management 

and conservation planning. Annals of the New York Academy of Science. 1162: 

79–98.
268

general technical report pnw-gtr-892

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.

Lotspeich, F.B.; Everest, F.H. 1981. A new method for reporting and interpreting 

textural composition of spawning gravel. Res. Note PNW-369. Portland, OR: 

U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and 

Range Experiment Station. 11 p.

Mantua, N.; Tohver, I.; Hamlet, A.F. 2010. Climate change impacts on 

streamflow extremes and summertime stream temperature and their possible 

consequences for freshwater salmon habitat in Washington state. Climatic 

Change. 102: 187–223.

Mauger, G. 2011. Summaries of 30 arc-second (~800m) snow products generated 

using the variable infiltration capacity (VIC) macroscale hydrologic model. 

[Database]. Seattle, WA: University of Washington, Center for Science in 

the Earth System, Joint Institute for the Study of the Atmosphere and Ocean, 

Climate Impacts Group. http://cses.washington.edu/picea/mauger/VIC_SNOW/

pub. (15 April 2013).

McCullough, D.A. 1999. A review and synthesis of effects of alterations to 

the water temperature regime on freshwater life stages of salmonids, with 

special reference to chinook salmon. EPA 910-R-99-010. Seattle, WA: U.S. 

Environmental Protection Agency, Region 10. 291 p.

Montgomery, D.R.; Buffington, J.M.; Peterson, N.P. [et al.]. 1996. Streambed 

scour, egg burial depths, and the influence of salmonid spawning on bed surface 

mobility and embryo survival. Canadian Journal of Fisheries and Aquatic 

Sciences. 53: 1061–1070.

Quinn, T.P.; Unwin, M.J. 1993. Variation in life history patterns among New 

Zealand chinook salmon (Oncorhynchus tshawytscha) populations. Canadian 

Journal of Fisheries and Aquatic Sciences. 50: 1414–1421.

Rand, P.S.; Hinch, S.G.; Morrison, J. [et al.]. 2006. Effects of river discharge, 

temperature, and future climates on energetics and mortality of adult migrating 

Fraser River sockeye salmon. Transactions of the American Fisheries Society. 

135: 655–667. 
269

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

Reeves, G.H.; Everest, F.H.; Nickelson T.E. 1989. Identification of physical 

habitats limiting the production of coho salmon in western Oregon and 

Washington. Gen. Tech. Rep. PNW-GTR-245. Portland, OR: U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station. 18 p.

Reeves, G.H.; Williams, J.E.; Burnett, K.M. [et al.] 2006. The aquatic 

conservation strategy of the Northwest Forest Plan. Conservation Biology. 20: 

319–329.

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. 

American Fisheries Society Symposium 70. Bethesda, Maryland: American 

Fisheries Society: 1127–1142.

Seiler, D.; Neuhauser, S.; Kishimoto, L. 2003. 2002 Skagit River wild 0+ chinook 

production evaluation: annual report. Olympia, WA: Washington Department of 

Fish and Wildlife. 51 p.

Snover, A.K.; Hamlet, A.F.; Lee, S-Y. [et al.]. 2010. Seattle City Light climate 

change analysis: climate change impacts on regional climate, climate extremes, 

streamflow, water temperature, and hydrologic extremes. Seattle, WA: University 

of Washington, Center for Science in the Earth System, Joint Institute for the 

Study of the Atmosphere and Ocean, Climate Impacts Group. 79 p.

Tabor R.A.; Celedonia, M.T.; Mejia F. [et al.]. 2004. Predation of juvenile 

chinook salmon by predatory fishes in three areas of the Lake Washington basin. 

Lacey, WA: U.S. Fish and Wildlife Service, Western Washington Fish 

and Wildlife Office. 78 p.

Tohver, I.; Hamlet, A.F.; Lee, S-Y. [In press]. Impacts of 21st century climate 

change on hydrologic extremes in the Pacific Northwest region of North 

America. Journal of the American Water Resources Association.

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.
270

general technical report pnw-gtr-892

U.S. Department of Agriculture, Forest Service [USDA FS]. 1995. Inland native 

fish strategy: environmental assessment: Decision notice and finding of no 

significant impact. Interim strategies for managing fish-producing watersheds 

in eastern Oregon and Washington, Idaho, western Montana, and portions of 

Nevada. [Place of publication unknown]: Intermountain, Northern, and Pacific 

Northwest regions.

U.S. Department of Agriculture, Forest Service [USDA FS]. 2005. Pacific 

Northwest Region aquatic conservation strategy. [Place of publication unknown]. 

28 p.

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. Department of Agriculture, Forest Service; U.S. Department of the 

Interior, Bureau of Land Management [USDA and USDI]. 1995. Decision 

notice/decision record: finding of no significant impact: environmental 

assessment for the interim strategies for managing anadromous fish-producing 

watersheds in eastern Oregon and Washington, Idaho, and portions of California. 

Washington, DC. 305 p. 

U.S. Department of the Interior, National Park Service [USDI NPS]. 2001.

Mount Rainier National Park general management plan. Ashford, WA: Mount 

Rainier National Park. 448 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2006.

Management policies 2006. Washington, DC: U.S. Government Printing Office. 

168 p.

U.S. Department of the Interior, National Park Service [USDI NPS]. 2009.

Final mountain lakes fishery management plan/environmental impact statement. 

Washington, DC.

U.S. Environmental Protection Agency [EPA]. 2007. Biological evaluation of the 

revised Washington water quality standards. Seattle, WA: Region 10. 197 p.

Waples, R.S.; Pess, G.R.; Beechie, T. 2008. Evolutionary history of Pacific 

salmon in dynamic environments. Evolutionary Applications. 1: 189–206.
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The North Cascadia Adaptation Partnership (NCAP) made significant progress on 

the climate change response of national forests and national parks in the partnership, contributed a synthesis of scientific information and potential management 

solutions, and catalyzed a collaboration of land management agencies and stakeholders seeking to address climate change in north-central Washington. The vulnerability assessment and adaptation options in this report, as well as the process used 

to develop them, enabled the national forests to accomplish several components 

of the U.S. Department of Agriculture Forest Service (USDA FS) climate change 

response strategy as outlined in the National Roadmap for Responding to Climate 

Change (USDA FS 2010a) and the Performance Scorecard for Implementing the 

Forest Service Climate Change Strategy (USDA FS 2012b), a tool for documenting 

unit-level progress. The goal of the agency is for all national forests and grasslands 

to accomplish all elements of the scorecard by 2015. The NCAP process contributed 

to the ability of participating forests to respond with “yes” to scorecard questions 

for three of the four dimensions: organizational capacity, engagement, and adaptation. Similarly, the NCAP process enabled participating national parks to make 

progress towards implementing several components of the National Park Service 

(NPS) Climate Change Response Strategy (CCRS) (USDI NPS 2010) by addressing 

communication, science, and adaptation goals. 

Relevance to Agency Climate Change Response 

Strategies

Here we summarize the relevance of the NCAP process to the climate change 

strategies of each agency and the accomplishments of participating national forests and parks. The scientific information in this report is also relevant for other 

land management agencies and stakeholders in the region. The NCAP process 

can potentially be implemented by any organization, and many of the adaptation 

options in this report are applicable throughout the Pacific Northwest and beyond, 

providing a starting point for adaptation planning in other locations. Similar to past

1 Crystal L. Raymond is a climate change strategic advisor, City of Seattle, Seattle City 

Light, 700 5th Avenue, Seattle, WA 98124 (formerly, research biologist, U.S. Department 

of Agriculture, Forest Service, Pacific Northwest Research Station, Pacific Wildland Fire 

Sciences Laboratory, Seattle, 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 Street, Suite 201, Seattle, WA 98103; 

and Regina M. Rochefort is a science advisor, U.S. Department of the Interior, National 

Park Service, North Cascades National Park Complex, 2105 State Route 20, Sedro-Woolley, 

WA 98284. 

Chapter 8: Conclusions

Crystal L. Raymond, David L. Peterson, and Regina M. Rochefort1
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adaptation efforts (e.g., Halofsky et al. 2011), a strong science-management partnership was critical to the success of the NCAP, and we encourage others to emulate 

this approach as a foundation for increasing climate change awareness, assessing 

vulnerability, and developing adaptation plans. 

Communication, Education, and Organizational Capacity

Organizational capacity, one of the dimensions in the USDA FS performance 

scorecard, requires training and education to build institutional capacity at the unit 

level, so that resource managers can better respond to climate change. The NCAP 

process built organizational capacity by providing training at two levels. One-day 

workshops provided basic education on applied climate change science and effects 

on natural resources at a level that was accessible to all employees. The workshops 

were well attended and strongly supported by unit supervisors, greatly contributing 

to successful outcomes. The 2-day workshops for each of the four resource sectors 

further built organizational capacity by providing indepth information on climate 

change effects on specific resources. These workshops introduced principles, tools, 

and processes for assessing vulnerability and planning for adaptation. Resource 

specialists who attended these workshops increased their capacity to address 

climate change in planning and project management. Climate change coordinators 

for each unit can also benefit from and continue to use the information generated 

during these workshops and summarized in this report. 

Communication and education are two components of the NPS CCRS. The 

strategy directs NPS staff to increase climate change knowledge and understanding 

among employees and to communicate this information to the public, along with 

information on actions taken by the NPS to respond to climate change. In addition 

to increasing climate change awareness among NPS staff, information gathered 

through the NCAP workshops will have cascading effects and raise awareness 

beyond those who attended the workshops. Through the NCAP process, participants 

shared information on additional tools and methods that could be used to assess 

vulnerability in greater depth or to assess vulnerability of resources and systems 

not included in this initial assessment. Climate change education for the public was 

beyond the scope of the NCAP, but knowledge generated through this process could 

be used for outreach and interpretive materials. The NCAP did engage a larger 

public audience in the workshop on hydrology and access by including several user 

groups, which was important for this issue because of its direct relevance to the 

public. During this workshop, participants discussed the potential to work with user 

groups to deliver information on the additional threats that climate change poses 

to access and the efforts that the USDA FS and NPS are taking to mitigate these 

effects.
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Partnerships and Engagement

In developing the NCAP, we focused on the partnership and process as much as the 

products because of the importance of partnerships in successful agency responses 

to climate change. Halofsky et al. (2011) identified as a “next step” of the Olympic 

climate change case study the need to include partners from other organizations 

and agencies in the planning process. We achieved this by building an inclusive 

partnership of scientists and managers from multiple agencies, organizations, and 

universities. 

The USDA FS performance scorecard elements on engagement include (1) 

building partnerships between managers and scientists and (2) incorporating 

climate change considerations into existing partnerships. The NPS CCRS emphasizes prioritizing the process, as well as products, and the need for interpersonal 

interactions and engagement as part of the process. Thus, participation in the 

NCAP increased unit-level compliance with the performance scorecard elements 

on engagement and the NPS CCRS. Resource managers interacted with scientific 

experts on climate change and its effects on natural resources, as well as with 

managers from other agencies that are working on similar challenges. 

The NCAP process strengthened interaction and engagement between the 

USDA FS and NPS, increasing capacity for a coordinated regional response to climate change. A regional response is important in the North Cascades because of the 

diversity of adjoining land ownerships. In this region, the USDA FS and NPS have 

collaborated on many issues in the past, and the NCAP increased awareness of the 

importance of a collaborative response to climate change. The NCAP also increased 

awareness among resource managers of differences in agency missions and objectives that may require different responses, as well as similarities that may provide 

opportunities for a coordinated approach. The science-management partnership 

will continue to be important in ongoing efforts to coordinate regional research on 

climate change and adaptation planning across jurisdictional boundaries. 

Assessing Vulnerability and Adaptation

Adaptation is included in the climate change response strategy of both the USDA 

FS and NPS. The adaptation dimension of the USDA FS performance scorecard 

includes (1) assessing vulnerability of human communities and ecosystems, and (2) 

conducting adaptation actions that reduce these vulnerabilities. The NCAP vulnerability assessment used the best available science to identify infrastructure, species, 

habitats, and ecosystems processes that are vulnerable to changes in climate. This 

information was then used to identify a “menu” of adaptation options that can 

be incorporated into existing programs and plans for each resource sector. The 

The NCAP process 

strengthened 

interaction between 

the Forest Service and 

National Park Service, 

increasing capacity for 

a regional response to 

climate change.
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science-management dialogue identified management practices that, in their current 

form or with slight modifications, are useful actions for increasing resilience, as 

well as new management practices for adaptation. Implementing all of these options 

may not be feasible, but resource managers can draw from this menu of options as 

needed and when resources permit. Several options are sufficiently defined that 

they could be implemented within the timeframe of the scorecard (by 2015), but the 

implementation of others may require policy changes or more resources and greater 

institutional capacity. Many options may be best implemented when management 

plans are revised or as threats emerge, although it will be important to consider 

these options before the effects of climate change are fully realized. 

Although the NCAP did not specifically follow the adaptation planning process 

as described in the NPS CCRS, the NCAP process did use many of the same principles and accomplished several of the goals for assessing vulnerability and planning for adaptation. The NPS CCRS recommends that units implement adaptation 

in all levels of planning to promote ecosystem resilience and enhance restoration, 

conservation, and preservation of resources (USDI NPS 2010). The strategy specifically requires adaptation to increase the resilience and sustainability of facilities, 

infrastructure, and cultural resources by identifying ways to incorporate climate 

change science into design and maintenance. Progress toward this goal was made 

through the analysis of climate change effects on hydrology and access. The NPS 

CCRS emphasizes that adaptation planning be conducted across disciplines and 

jurisdictional boundaries, as was initiated through the NCAP. 

Science and Monitoring

Monitoring is an element of the USDA FS performance scorecard, and the NPS 

CCRS stresses the importance of science, research, and monitoring. The NCAP 

addressed monitoring by identifying current monitoring programs that provide 

useful information for detecting effects of climate change, as well as new indicators 

and priority ecosystems and species requiring additional monitoring. Cross-jurisdictional connections that were initiated or strengthened through the NCAP may 

increase opportunities for collaborative monitoring of climate change effects and 

adaptation effectiveness at a regional scale. Many of the adaptation options inspired 

discussions of research needs for detecting changes, attributing changes to climate, 

and assessing the effectiveness of adaptation. Throughout the process, we used 

the best available science on projected changes in climate and effects on natural 

resources at the finest resolution that is scientifically valid. National forests and 

national parks in the region work closely with scientists from several agencies and 

universities to conduct research. Discussions between these scientists and managers 
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during the NCAP workshops have already led to additional research collaborations 

to meet information needs of land managers. 

Mitigation and Sustainable Operations

It was beyond the scope of the NCAP to address elements of the USDA FS scorecard and NPS CCRS pertaining to carbon assessments, mitigation, and sustainable 

operations. The USDA FS is engaged in efforts to assess carbon and increase the 

sustainability of operations within many forest units. The two national parks in 

the NCAP participated in the Climate Friendly Parks Initiative, which emphasized 

mitigation and reducing emissions from park operations. 

Next Steps

Engagement and Partnerships

The NCAP expanded on previous science-management partnerships by creating an 

inclusive forum through which local and regional stakeholders could discuss crossboundary issues related to vulnerability and adaptation, but more work is needed to 

truly achieve an “all lands” approach to adaptation. The agencies involved have different missions and objectives and are at different stages in the process of responding to climate change. These differences allowed agencies to share approaches and 

learn from the experiences of others, but they presented challenges for the development of collaborative adaptation plans. The NCAP national forests and national 

parks collaborate with partners on many issues, and it was difficult to determine 

the appropriate partners to include in this process. An all-lands approach may be 

more effectively achieved by considering climate change in existing partnerships 

that already focus on a single issue or a narrow range of issues. Another potential 

approach is to develop partnerships around specific resources identified by this 

report as being highly sensitive to climate change. Interactions through the NCAP 

process, both among agencies and between scientists and managers, have already 

led to new collaborative research and adaptation planning efforts. 

Vulnerability Assessment and Adaptation Planning

The scope of this vulnerability assessment was intended to be broad and cover a 

range of natural resources. By exploring four resource areas in detail—hydrology 

and access; vegetation; wildlife; and fish—participants identified several species, 

ecosystems, and ecosystem processes that are sensitive to climate change. In the 

future, more detailed, quantitative, and spatial vulnerability assessments would 

improve adaptation options summarized in this report by increasing specificity of 

adaptation tactics and prioritizing locations for implementation. 
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The vulnerability assessment could be expanded to cover additional systems 

and ecosystem processes. The effects of climate change on natural resources in 

the NCAP national forests and national parks will likely have implications for 

the economies of adjacent communities. Assessing the vulnerability of social and 

economic systems is an important next step for the North Cascades region. It will 

also be beneficial to integrate carbon assessments with vulnerability assessments 

of ecosystem processes. Although carbon assessments are a separate element in 

the USDA FS scorecard, climate change effects on carbon stocks and sequestration 

could be integrated into ecosystem vulnerability assessments. Integrating these 

concepts would improve evaluation of tradeoffs and “win-win” situations for both 

adaptation and mitigation actions. For example, one could assess how thinning 

prescriptions and fire management plans adapted for a changing climate affect 

carbon sequestration. 

Implementing Adaptation Strategies and Tactics

The most important and potentially most challenging next step is to implement 

adaptation strategies and tactics in resource management plans and projects. We 

anticipate that implementation will occur gradually over time, with major advances 

occurring as specific needs arise or in response to disturbances, extreme events, 

plan and program revisions, and changes in policies and regulations. The assessment of implementation opportunities summarized in each chapter can be used 

to identify pathways and partnerships for implementing options into the current 

management framework. As with the initial planning process, implementation will 

require collaboration among multiple landowners and management agencies in the 

region. 

A Vision for Adaptation as a Dynamic Process

In some cases, similar adaptation options were identified for more than one 

resource sector, suggesting a need to synthesize and integrate adaptation planning 

across disciplines. Examples include coordinating adaptation of vegetation management with that of wildlife habitat, and coordinating adaptation of infrastructure 

design with management of aquatic habitat. Adaptation options that provide benefits to more than one resource are likely to have the greatest effect and are thus 

more likely to be implemented (Halofsky et al. 2011). Conversely, some adaptation 

options involve tradeoffs (e.g., some actions may enable adaptation for one resource 

at the expense of another) that could be explored in greater detail to prevent unintended consequences. The NCAP resource sector workshops included specialists 

The most important 

and challenging next 

step is to implement 

adaptation in resource 

management plans and 

projects.
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from related disciplines, and integrative concepts were discussed and explored, but 

an important next step is to develop interdisciplinary teams to explore tradeoffs and 

benefits. 

Just as with a recent national perspective on the role of climate change adaptation in federal agencies (Peterson et al. 2011), we are optimistic about how the 

adaptation process will evolve in north-central Washington. In the future, we 

anticipate that:

• Climate change will be incorporated in planning, projects, and on-theground activities similar to how other stressors such as fire, insects, and 

human activities are currently addressed in resource management. 

• Assessments of the effects of climate change and other natural and human 

factors on ecosystems will be periodically developed, including updated 

scientific documentation.

• Monitoring activities will include indicators that detect the effects of climate change on species and ecosystems, and monitoring data will be used 

to make periodic adjustments in planning and project management.

• Agency planning processes will be sufficiently flexible that climate change 

assessments and management objectives will be used to identify opportunities for managing across boundaries.

• Effects of climate change on ecosystem services will be examined to 

determine if near-term management options can reduce undesirable future 

effects. 

• Restoration activities will be designed and implemented in the context of 

the potential influence of climate change on the success of those activities.

• Management of carbon will be coordinated with adaptation planning.

• Institutional capacity for adaptation will increase within federal agencies 

as resource managers acquire technical expertise on climate change and 

increasingly communicate with scientists to implement “climate smart” 

management. 

The USDA FS and NPS are in transition from viewing climate as unchanging to viewing climate as dynamic and mediating changes in the environment 

(Halofsky et al. 2011, Peterson et al. 2011, Swanston and Janowiak 2011). Evolving 

science and climate policy, combined with near-term changes in ecosystems will 

necessitate iterative evaluation of adaptation options for land management. We are 

currently being deluged by new information about the effects of a changing climate 

on ecosystems. Resource managers are observing changes in weather and ecological disturbances and responding to those changes on the ground, thus learning 
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about adaptation. This report provides a foundation for selecting and implementing 

adaptation practices, which can be continually revisited as part of adaptive management in the broadest sense of the term, facilitating the functionality of ecosystem 

processes in preparation for a warmer world.

Acknowledgments

We thank leadership and resource managers of Mount Baker-Snoqualmie National 

Forest, Okanogan-Wenatchee National Forest, North Cascades National Park 

Complex, and Mount Rainier National Park for their support of the North Cascadia 

Adaptation Partnership (NCAP). We thank all participants in NCAP workshops 

on education, vulnerability assessment, and adaptation for their enthusiasm and 

contributions. Numerous reviewers, mentioned in the acknowledgments of individual chapters, provided insightful comments that greatly improved this publication. Ellen Eberhardt provided outstanding editorial assistance with all aspects of 

manuscript preparation. Funding was provided by the U.S. Forest Service Pacific 

Northwest Research Station; we are particularly grateful to Dr. Cynthia West for 

her support. Robert Norheim produced the maps in this publication. Our hope is 

that the NCAP will maintain an ongoing dialogue about climate change in the years 

ahead, catalyzing activities that promote sustainability in the remarkable ecosystems of the North Cascades region. 

Literature Cited

Halofsky, J.E.; Peterson, D.L.; O’Halloran, K.A.; Hoffman, C.H. 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.

Peterson, D.L.; Millar, C.I.; Joyce, L.A. [et al.]. 2011. Responding to climate 

change in national forests: a guidebook for developing adaptation options. Gen. 

Tech. Rep. PNW-GTR-855. Portland, OR: U.S. Department of Agriculture, 

Forest Service, Pacific Northwest Research Station. 109 p.

Swanston, C.W.; Janowiak, M.K., eds. 2011. Forest adaptation resources: climate 

change tools and approaches for land managers. Gen. Tech. Rep. NRS-GTR-87. 

Newtown Square, PA: U.S. Department of Agriculture, Forest Service, Northern 

Research Station. 108 p.
279

Climate Change Vulnerability and Adaptation in the North Cascades Region, Washington

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010a. National 

roadmap for responding to climate change. http://www.fs.fed.us/climatechange/

pdf/roadmap.pdf. (28 August 2012).

U.S. Department of Agriculture, Forest Service [USDA FS]. 2010b. A 

performance scorecard for implementing the Forest Service climate change 

strategy. http://www.fs.fed.us/climatechange/pdf/performance_scorecard_final.

pdf. (28 August 2012).

U.S. Department of the Interior, National Park Service [USDI NPS]. 2010.

National Park Service climate change response strategy. Fort Collins, CO: 

Climate Change Response Program. 28 p. 

http://www.nps.gov/orgs/ccrp/upload/NPS_CCRS.pdf. (28 August 2012).
Pacific Northwest Research Station

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