During its August aerial detection survey, the U.S. Forest Service captured this view of dead and dying trees on the Sequoia and Sierra national forests.
Photo courtesy of the U.S. Forest Service

Five years of drought has made most of us conscious of our water use, and more aware of rain and snow. Limitations on lawn watering and car washing may have even created some inconveniences.

But the state’s forests have suffered a significant toll during this period. Last month, the U.S. Forest Service reported that since 2010, more than 100 million trees have died from the drought and bark beetle attacks. Nearly one-third have died since May, according to the Forest Service’s aerial surveys of nearly 4.5 million acres of the state’s forest lands, almost all in Northern California.

Also, millions more trees are threatened from lack of water and insects. Until more rainfall occurs, the trees remain endangered and the number of dying trees will continue to increase. 

In response, the Forest Service has moved nearly $43 million within its budget to conduct safety-focused restoration projects along roads, trails and recreation sites. The San Bernardino National Forest’s budget for fuels mitigation work has remained steady at $2.3 million, according to John Miller, public affairs officer for the forest.

The drought also makes it more difficult for the state’s pines to stave off attacks from insects, especially the bark beetle, which also has been a major contributor to the forests’ thinning. According to the Forest Service reports, “… tree health is in serious decline, often compromised by the existence of too many trees competing for limited resources, especially water.”

However, the growing number of dead trees is not significantly increasing the threat of wlldland fires, according to the Forest Service. “Typically, beetle-killed trees shed their needles within a few months of dying, so they don’t create as big a threat to fire spread as expected. However, high amounts of dead trees do present a threat of spotting when a forest fire is burning around them. Once trees fall, a fire could potentially burn longer and hotter, damaging soils and adversely affecting the site in the long-term.”

Once the beetles have infested a tree, there is little to do. But the agency is trying to improve the forest conditions by reducing competition for vital resources through expansion of its thinning programs.


  1. While I approve of this article the bark beetle cycle is far more complex than presented here. Certainly drought is a major contributing factor but a long history of fire suppression and a lack of timber management resulting in vast tracts of overcrowded trees with a uniform composition coupled with warmer winters that fail to keep the beetle population in check and warmer summer temperatures that speed up beetle development are also factors. Furthermore, causative factors in northern latitudes may be different than those in the mountains of Southern California. This phenomenon deserves more discussion than this venue allows, and I encourage interested parties to delve more deeply into the matter.