Between 2012 to 2017 and Over 100 million trees died due to many years of drought that weakened the trees and left millions of acres of forestland highly susceptible to insect attacks. The drought stress is exacerbated in forests with too many trees competing for limited resources, especially water. Tree loss due to drought stress and bark beetle attacks are expected to increase until precipitation levels return to normal or above normal for one to multiple years.

On October 30, 2015 Governor Brown issued an emergency proclamation and established the California Tree Mortality Task Force (now the Tree Mortality Working Group of the Forest Management Task Force). And on September 1, 2017 Governor Brown issued Executive Order B-42-17 to bolster the state's response to the unprecedented tree die-off.

One goal of the task force was to identify and map areas of tree mortality that pose the greatest potential of harm to people and property. These areas, known as High Hazard Zones, are the areas prioritized for tree removal. 

LAUNCH THE VIEWERTree Mortality web viewer


Download HHZ Data

FRAP has created a web-based mapping application through which you can view theTier 1 and Tier 2 High Hazard Zones (HHZ) as well as associated information. Tier 1 HHZ are where mortality and asset to be protected (utilities, roads, recreation sites, etc) directly coincide with mortality identified by the USFS Aerial Detection Survey (ADS) for the years 2012 through 2017. Tier 2 HHZ is based on HUC 12 watersheds (average 24,000 acres) and are intended to focus on ecosystem health and identify watersheds where there is both the greatest amount of ecological asset to be proteced as well as the greatest threat.

Forest Management Task Force

With the subsidence of the drought and the associated tree mortality, the Tree Mortality Task force is now a working group under the Forest Management Task Force. California's Forest Management Task Force was organized to protect the environmental quality, public health, and economic benefits that healthy forests provide to California. The Task Force aims to increase the rate of forest treatments and expand state wood product markets through innovation, assistance, and investment. Advancing forest health project capacity, readiness, and completion statewide aligns with the California Forest Carbon Plan, the goal of which is to establish healthy and resilient forests that can withstand and adapt to wildfire, drought, and a changing climate. 

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