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Individual Highlight

Early tree mortality forecasts help California mitigate fire risk

Photo of Number of trees projected to die by end of summer 2017. Red areas of map indicate intense levels of tree mortality due to drought, bark beetles, and wood borers; dark blue areas represent a low likelihood of any mortality. Number of trees projected to die by end of summer 2017. Red areas of map indicate intense levels of tree mortality due to drought, bark beetles, and wood borers; dark blue areas represent a low likelihood of any mortality. Snapshot : Forecasts help protect public health and property.

Principal Investigators(s) :
Grulke, Nancy E. 
Research Location : California
Research Station : Pacific Northwest Research Station (PNW)
Year : 2017
Highlight ID : 1341

Summary

Five consecutive years of drought and warmer than normal temperatures created prime conditions for bark beetle and wood borer outbreaks in parts of California. As a result, large parts of California are currently experiencing dramatic levels of tree mortality and heightened fire risk. Forest Service Forest Health Protection staff conduct aerial surveys to collect data and map the extent and severity of tree mortality; this information is compiled and finalized across the summer months. However, having tree mortality forecasts prior to fire season would allow land managers to better prioritize hazard tree removal, pest suppression activities, and fuels reduction treatments. Recognizing this need, the Forest Service’s Pacific Southwest Research Station collaborted with their colleagues in the agency’s Western Wildland Environmental Threat Assessment Center and Forest Health Protection staff to develop a tool that yields early, accurate forecasts of tree mortality. The 2015 forecast was only 2 percent outside the expected range of mortality, based on the later 2015 survey data. The 2017 mortality map was available in early 2017. California's Department of Forestry and Fire Protection used the forecast to identify areas with increased fire risk. Forest Service managers in the Pacific Southwest Region are also using the forecast to identify areas in need of spot treatment; for example, managers of the El Dorado National Forest used the mortality maps to strategically reduce fire hazard in high risk areas.

Forest Service Partners

External Partners

  • Pacific Southwest Region Forest Health Protection, Pacific Northwest Region Forest Health Protection