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

Restoration strategies to create resilient forests

Close up photo of duff, needles and other organic debris at the base of a tree.
Download "Creating More Resilient Forests Through Active Management" to get additional information on how to create resilient landscapes.

Drought, combined with higher temperatures, is contributing to "megadisturbances" that threaten western forests and require a new approach to silviculture management. Researchers at PSW are studying how changing climatic conditions will likely transform the forests of the future.

To proactively manage forests in the face of a changing conditions, “An Ecosystem Management Strategy for Sierran Mixed Conifer Forests,” is a Pacific Southwest Research Station general technical report that offers land managers a conceptual approach for managing forests in the Sierra Nevada.  

One important factor to forest restoration is complexity – or heterogeneity – that can improve a forest’s ability to respond to stress and disturbances, while still supporting wildlife. Complexity includes varying stand density, including openings of various sizes, a mix of tree sizes and ages, and the presence of shrubs and meadows. Given enough space, sunlight, nutrients and water, trees have the capacity to grow and thrive.

Current study: King Fire Reforestation Seed Choice Based on a Changing Climate

Ecological restoration projects that include reforestation require land managers to select the appropriate source of seeds for the planting location. In California, traditional approaches for making this choice are based on seed zone and elevation band. However, this geography-based measure leads to the question of whether or not this is the best approach in a changing climate.

To test this question, working with the Eldorado National Forest, PSW established a test with Ponderosa and Sugar pine trees as part of the King fire reforestation effort. On the Georgetown Ranger District, 1,300 trees were planted into 13 acers and were individually tagged and mapped for future data collection. The seeds for the trees were selected from a range of seed zones and elevation bands across California, focusing on ones that are currently warmer than the planting site. Over time, researchers will monitor growth and survival of these trees, and determine which source of seeds performed best at the planting site. This information will help inform land managers who need to select seeds for reforestation projects in the future.

Forest Insights: Using the Past to
Reshape the Future

Historical data from the Sierra Nevada provide a window into the past about the type of conditions that existed before fire suppression and logging.

In this video, researchers discuss these historical conditions and share a new study that is recreating spatial patterns seen in historic forests. These treatments are helping make a forest resilient to fire, drought and bark beetles.

Additional resources