USDA Forest Service

Pacific Southwest Research Station

Pacific Southwest
Research Station

800 Buchanan Street
Albany, CA 94710-0011
(510) 883-8830
United States Department of Agriculture Forest Service. USDA logo which links to the department's national site. Forest Service logo which links to the agency's national site.

Research Topics Tree Mortality

Tree Mortality in California

Since 2010, an estimated 129 million trees have died in California’s national forests due to conditions caused by climate change, unprecedented drought, bark beetle infestation and high tree densities. Most visible and immediately concerning are the high number of hazard trees in and around communities and campgrounds and along roads, trails and power lines.

The U.S. Forest Service’s Pacific Southwest Research Station (PSW) has been working with the Pacific Southwest Region (Region 5) to address tree mortality by using existing science and identifying future research opportunities.

In July 2017, Region 5 and the USDA California Climate Hub co-hosted a two-day science symposium on drought and tree mortality. Participants examined the effects of drought, beetle activity and past wildland fire management practices on tree mortality across the landscape, as well as considered ways to address these issues in the future.

A summary of their key points and findings are detailed in "Drought and Tree Mortality in the Pacific Southwest Region."


Bark Beetles


Fire Management


Land Management Collaboration

Land Management

Restoration Strategies


Wildlife Management


Additional Resources