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Lassen Tree Mortatilty Task Force

Why a Tree Mortality Task Force?

May contain: plant, tree, conifer, pine, abies, and fir

California has experienced moderate to exceptional drought conditions for the past five years. As a consequence, more than 102 million trees have died on the state’s drought-stricken forests. The highest numbers of dead trees are found in the Central and South Sierra Nevada but increases in tree mortality have also been reported in Northeastern California over the past two years. Most of the mortality has been the result of bark beetles attacking drought stressed trees.

Increases in tree mortality in Northeastern California started during the same time period as in the rest of California but have not been as elevated since drought conditions have not been as severe. A 2016 aerial tree mortality survey by the US Forest Service of Lassen County identified approximately 876,000 dead trees, which was about 35% more than were mapped in 2015 and well above what would be considered normal background tree mortality. While the number of dead trees mapped over the past two years is high, it is still estimated to be <1% of the total number of trees growing within Lassen County.

What has been done?

May contain: tree, plant, pine, abies, and fir

In 2014, California Governor Edmund G. Brown Jr. proclaimed a State of Emergency and directed state officials to take all necessary actions to prepare for drought conditions. A state-level multi-agency and organization Tree Mortality Task Force was formed to coordinate emergency protection actions and monitor conditions to address the vast tree mortality occurring from the drought and subsequent bark beetle infestations. In response to the state-level task force, the Lassen County Tree Mortality Task Force was organized in August 2016 to address local mortality issues or prepare for the potential.

The following agencies are represented on the Lassen County Tree Mortality Task Force:

  • Lassen County Office of Emergency Services,
  • City of Susanville,
  • Sierra Nevada Conservancy,
  • US Forest Service,
  • Natural Resource Conservation Service,
  • Honey Lake Valley Resource Conservation District,
  • Lassen Co. Fire Safe Council,
  • Lassen Municipal Utilities District,
  • Pacific Gas & Electric,
  • Greenleaf Power,
  • W.M. Beaty & Associates, and
  • Sierra Pacific Industries.

One focus of the Task Force is to educate the public about forest health and the importance of being proactive when it comes managing their trees and forests to better prepare for times of drought. This includes teaching property owners the visible signs that indicate a tree has been infested with bark beetles, informing them of the need to remove dead and dying trees and encouraging them to reduce the density of living trees and other vegetation on their property to increase resistance to bark beetles and reduce fire hazards. 

Where do I get help or more information?

May contain: plant, tree, conifer, fir, and abies

Information and assistance is available to landowners to create and maintain healthy tree and forest conditions or to assist in addressing tree mortality issues on their property. Contact the California Department of Forestry and Fire Protection – Lassen-Modoc Unit at (530) 257-4171 or download a list of registered professional foresters at

Several publications are also available electronically to assist with tree species identification, signs and symptoms of bark beetle attack and treatment options for protecting individual trees before bark beetles attack: 

Additional resources: