Trees dying due to drought are prone to wildfire

May 18, 2015

Across California, pine trees that have been weakened by the drought are having trouble defending themselves from bark beetles, causing widespread tree death. The dead trees won't cause fires, but when ignited they will be hotter and be more difficult to control, according to articles that ran over the weekend in the Santa Rosa Press-Democrat and the Desert Sun.

“Statewide, it's horrific,” said Greg Giusti, UC ANR Cooperative Extension advisor.

Max Moritz, UC ANR Cooperative Extension specialist in fire ecology, described the combination of exceptionally low vegetation moisture and widespread plant deaths as "a double-barreled threat."

"On top of the dry conditions, it's been unusually hot in many, many parts of the state," Moritz said. "We do have a pretty exceptional fire season stacking up, or the potential for one."

The Los Angeles Times also covered the story earlier this month.

Scott Stephens, fire science professor at UC Berkeley, said fire suppression and harvesting have made forests more dense over the last 100 years. The increased density has made trees more vulnerable as they compete for limited amounts of water, with the weaker trees more susceptible to bark beetle infestations, he said.

“If the drought continues for another two years or longer, I expect this mortality to move throughout the state,” Stephens said. “Forests that once burned frequently with low-moderate intensity fire regimes are the most susceptible.”

By Jeannette E. Warnert
Author - Communications Specialist