USDA Forest Service

Pacific Northwest Research Station

Pacific Northwest Research Station
1220 SW 3rd Ave.
Portland, OR 97204

(503) 808-2100

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Competition and climate change

Crowding alters the impact of climate on tree growth


Douglas-fir wood in cross section. Photo credit: Edgard Espinoza, 2017.
Mount Rainier National Park. Photo credit: Parker Knight via Compfight cc.

In the rugged landscape of Mount Rainier National Park in Washington, a team of researchers surveyed trees in mature and old-growth forests of mostly Pacific silver fir, western hemlock, and western redcedar. Some of the stands they visited were over 1,000 years old. The study team was interested in finding out how climate affects tree growth and how competition with other trees complicates this interaction. Tree growth helps forests take up carbon, and forests in the Pacific Northwest provide exceptionally high levels of carbon storage. So anticipating how tree growth might respond to future climates is important.


To address these questions, the team compared their measurements of tree size with data from the same sites going back to the late 1970s. They fed this data into computer models that allowed them to characterize the joint influences of tree size, competition, and climate on diameter growth. They found that for individual trees, growth rates were often highly sensitive to differences in climate under low competition but mostly insensitive under high competition. This is probably because the ability of trees to respond to more favorable climatic conditions is constrained by competition for resources. Thus, climate change will likely increase individual growth most in uncrowded stands with lower competition. Because growth responses to climate depend on the tree’s local competitive environment, forest managers should expect climate change effects on tree growth to vary across the landscape.


Contact: Connie Harrington,


More information: Competition alters tree growth responses to climate at individual and stand scales


Ranching and protecting fish habitat

Social and ecological factors


Cattle grazing on Starkey Experimental Forest and Rangeland. Photo credit: Rhonda Mazza.
Starkey Experimental Forest and Rangeland. Photo credit: Rhonda Mazza.

Ranching continues to be an important livelihood in the rural West. On these working landscapes, people and natural resources are closely intertwined, and their mutual well-being is key to the sustainability of rangeland ecosystems. Environmental anthropologist Susan Charnley explores the human dimensions of land management. She recently led a study in the Blue Mountains of northeast Oregon addressing the management challenges associated with the recovery of threatened fish species on federal lands where cattle grazing is a dominant type of land use. Since the 1990s, when several fish species in the Blue Mountains were first listed under the Endangered Species Act, the question of how to manage livestock grazing in the region's national forests while simultaneously protecting habitat for listed fish has engendered considerable conflict, including litigation.


Charnley worked with ecologists Mary Rowland and Michael Wisdom along with other social scientists to conduct research in collaboration with local stakeholders to understand the social and ecological dynamics influencing the sustainable coexistence of fish and livestock on federal lands in the region. The team is involved in management experiments at the Starkey Experimental Forest and Range to find solutions designed to reduce the impact of cattle on riparian areas. They argue that research on controversial topics calls for the involvement of all stakeholders—including local ranchers, environmentalists, natural resource managers, scientists, elected officials, and tribal government representatives—to build trust and improve the research and monitoring process.


Contact:  Susan Charnley,


More information: Cattle grazing and fish recovery on US federal lands: can social–ecological systems science help?
See also:


How do birds respond to forest management?

Long-term implications in mature forests


Scarlet tanager. Photo credit: Matt Ward via Compfight cc.
Scarlet tanager. Photo credit: Matt Ward via Compfight cc.

In some places, bird species associated with mature forests are facing population declines. When trees in these forests are harvested, the approach used can make a big difference for forest bird species long into the future. How do intense treatments like clearcuts affect bird species 10 or more years after the treatment? Wildlife biologist Julianna Jenkins is helping address this question. She and several co-authors recently published one of the longest duration studies of forest bird responses to timber harvest in the Eastern United States. They looked at the effects of different harvesting methods on 18 bird species associated with mature forests in the Ouachita Mountains of Oklahoma and Arkansas. Managers can put the information from this study immediately to use, as the Ouachita National Forest is consistently among the top five national forests in annual timber output.


The study team surveyed birds for 16 years after harvest. They found that most species responded positively to partial timber harvest that retained mature overstory trees. Less intensive harvests had positive effects on more species and negative effects on fewer species than more intensive harvests, but responses to different treatments varied among species. Ovenbird and scarlet tanager responded negatively to all timber harvests; ovenbird appeared to be particularly susceptible to timber harvest, especially more intensive harvests such as clearcut. No harvest method appeared to be optimal for all mature forest birds.

Contact: Julianna Jenkins,

More information: Long-term effects of different forest regeneration methods on mature forest birds


Forest collaborative groups in Oregon

Their motivation factors and definitions of success


Blue Mountains Forest Partners collaborative. Photo credit: Vernita Ediger.
Blue Mountains Forest Partners collaborative. Photo credit: Vernita Ediger.

Forest management challenges in the West are large in scale, and the resources to deal with them are not keeping pace. To broaden support and increase capacity to achieve management goals, many public land managers engage with place-based forest collaborative groups, which typically include a range of local stakeholders and organizations. Oregon leads the United States in the number and extent of collaborative groups on national forests, with at least 25 established groups. Research social scientist Eric White worked with Oregon State University colleague Emily Jane Davis and several other co-authors on a study of Oregon’s forest collaboratives to examine what motivates them and how they define success.


The team undertook a statewide survey of forest collaborative participants to develop a better understanding of what is important to collaborative members and their perceptions of success. A majority of respondents reported satisfaction with their collaborative. However, the study revealed some interesting differences between participants from the U.S. Forest Service and those outside the agency. The primary motivation for agency participants to join a collaborative was to build trust. Nonagency respondents reported a diversity of primary motives, the most common of which were restoring forest resiliency, protecting fish and wildlife habitat, and getting more timber supply off public lands. Understanding these kinds of differences is important for federal agencies such as the Forest Service, because they want to incorporate public input and the greatest good in their management decisions. This is particularly relevant in Oregon, where federal agencies manage 60 percent of all forested land in the state.


Contact:  Eric White,


More information: Comparison of USDA Forest Service and stakeholder motivations and experiences in collaborative federal forest governance in the Western United States

What's New

Forest Service Deputy Chief for Research and Development Carlos Rodriguez-Franco recently recognized landscape ecologist Paul Hessburg with a Deputy Chief’s Distinguished Science award. Hessburg was selected for the honor for his groundbreaking contributions to the science of landscape ecology and his exceptional leadership and for science delivery in service to natural resource management.

For more information: Agency scientists recognized with Deputy Chief’s Awards





Envision agent-based landscape model

This geographic information system-based modeling framework simulates fire behavior, forest succession, and forest management across multiple ownerships in large fire-prone landscapes. Researchers can use it to explore how human decisionmaking affects fire behavior, forest succession, wildlife habitat, and ecosystem services across multi-ownership landscapes. It has been used with forest collaboratives in central Oregon who designed management scenarios that researchers then simulated with the model. The tool is primarily intended for use by researchers or managers with computer modeling expertise. 

How to get it:   

Contacts: Thomas Spies,; Alan Ager,; Eric White,





Featured Scientist

Eric White, Research Social Scientist.Forests, public lands, and open spaces contribute to human well-being in many ways. Research social scientist Eric White helps land managers, policymakers, and communities understand the social and economic outcomes of some of the most immediate and meaningful ways in which people and landscapes interact, such as through outdoor recreation, addressing wildfire risk, and collaborative natural resource management.


White has a master’s degree in forestry and a Ph.D. in natural resource policy and economics. His work frequently explores social and economic trends related to public lands and rural landscapes. For example, he has studied rural land development, projecting that the developed area in the United States will increase by 22 million between 2003 and 2030. He also studied how natural amenities in rural areas (such as scenic views, open space, lakes and rivers, or public land) influence property values.

Recreation visitor spending is the largest single source of economic activity associated with U.S. national forests. With White’s expertise in outdoor recreation, he has become a leading source of information for public land management agencies on the role of recreation on federal land in local and regional economies. His research examines what types of recreation occur on public lands, how to quantify the economic benefits of recreation on national forests, and how many jobs and other economic activity are generated as a result of recreation in specific places. He recently published a report that summarizes outdoor recreation trends and provides projections of future participation in recreation activities. He also serves on the national advisory team for the Forest Service’s National Visitor Use Monitoring program.


White’s research provides accurate and highly useful information on the estimates of average recreation visitor spending on national forests. Likewise, in a report commissioned by the state of Oregon to analyze the economic activity generated by Oregon’s state parks, White found that spending in the local areas around Oregon state parks supports about 16,000 full- and part-time jobs and generates total labor income of $583 million. Yet he also encourages land managers and policymakers to think beyond number values and consider the concepts and relationships that drive how recreation affects people and communities. Last year, he was invited to give a presentation for the prestigious Starker Lecture Series hosted by Oregon State University’s College of Forestry: Contributions of outdoor recreation to people and the economy.


Social and economic issues are deeply intertwined in Pacific Northwest forests and White also seeks to understand how these linkages influence natural resource policies and management. Current projects focus on integrating social and economic factors into these coupled human and natural systems.


In recognition of his commitment to sharing his knowledge with as many practitioners as possible, White recently won the Pacific Northwest Research Station Director’s award for science delivery. When he’s not working, you can find him out in the forests and on the hiking trails, getting first-hand knowledge of the quality-of-life benefits of outdoor recreation and public lands.



US Forest Service - Pacific Northwest Research Station
Last Modified: Monday,09April2018 at12:15:01CDT

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