Publication Date June 27, 2016 | Wall Street Journal

California’s Wildfire Fueled by Dead Trees

United States
Trees are dying at a rapid rate in portions of the Sierra Nevada because of drought and bark beetles. Photo: Eric Paul, Zamora / Zuma Press
Trees are dying at a rapid rate in portions of the Sierra Nevada because of drought and bark beetles. Photo: Eric Paul, Zamora / Zuma Press

Drought, extreme heat and high winds have fueled wildfires across the western U.S. this month. But another enemy is driving California’s most destructive blaze of the fire season so far: tens of millions of dead trees.

California Gov. Jerry Brown declared a state of emergency Friday evening in central California’s Kern County, where a wildfire has grown to more than 36,000 acres and killed two people...

Despite lower winds, the fire is expected to remain active into Sunday evening due to triple-digit temperatures...

[O]fficials say dead trees are playing a large role in its power and volatility.

Bark beetles, heat and California’s five-year drought have caused 66 million trees to die in the state’s Sierra Nevada forests since 2010, the U.S. Forest Service said last week.

The death rate of these trees has increased rapidly within recent months, with 26 million trees dying in and around the Sierra Nevada forests since October 2015.

“This is a major problem that is going to be an issue for several fire seasons to come,” said Stanton Florea, the U.S. Forest Service’s fire information officer for the state...

Other larger wildfires in the state so far this season haven't been fueled by these dry, dead trees, since they have occurred at lower elevations. The tree mortality becomes a factor at 3,000 feet of elevation, says Dan Berlant, chief information officer at the California Department of Forestry and Fire Protection, or Cal Fire...

These dead trees are significantly drier and are vastly more flammable than ones that are still alive, says Wally Covington, director of the Ecological Restoration Institute at Northern Arizona University. Pairing dry, dead trees with a fire and windy conditions makes for “the worst-case scenario,” he said.

As the trees in California grow weaker due to lack of water, they are unable to battle an increased population of bark beetles, which infest and eat away at the trees, Mr. Covington said