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Fifth National Climate Assessment - Read the Report

Measuring ecosystem response to changing environments in Pacific Northwest forests

Scientists are combining satellite remote sensing and ground survey data to better understand the impacts of climate change and other disturbances on the health of Pacific Northwest forests and the ecosystem services they provide. 

Pacific Northwest forests are sensitive to temperature and drought stress and face increased vulnerability to insect pests, diseases, and fires in a changing climate. The frequency and severity of climate-related forest disturbances are expected to continue to increase over the 21st century. These impacts, combined with expected decreases in snowpack and the potential for decreased forest cover in watersheds, can jeopardize the ecosystem services these forests provide, including water quality protection and the ability to store carbon. Key information gaps and scientific uncertainties currently limit our ability to predict tree growth and decline in response to climate change and climate-related forest disturbances such as wildfire and insect outbreaks. Addressing these information needs requires coordinated observation systems and experiments at local, regional, and global scales.

Aerial surveys and satellite remote sensing data are key to understanding the effects of important disturbance agents, primarily forest insects and fire, on the landscape scale. However, these methods generally fail to detect disturbances whose symptoms are sporadic in time and space, such as foliage disease; as a result, the role of some biotic disturbance agents has not been adequately addressed. Understanding biotic disturbances by forest type, and how they interact with climate conditions, is critical to predicting how forests will respond to future change and what the effects on ecosystem services will be.

Scientists from EPA and the USDA Forest Service are combining aircraft and satellite-based remote-sensing data with on-the-ground surveys to better understand the interacting effects of climate variability and change and forest disturbances on forest health and the ecosystem services they provide to surrounding communities. A key finding is that forces that drive disturbances in widespread and economically important Douglas-fir forests of western Oregon and Washington— including pests, diseases, forest management practices, and wildfire—are being influenced by climate change. These changes may result in a need to revise forest management plans.