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Environment & Science

How tree die-off could impact California's wildfires

Tree die-off captured in Fresno County in February 2016
Tree die-off captured in Fresno County in February 2016
California Department of Forestry and Fire Protection

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California's Sierra Nevada has lost more than 29 million trees since 2015, adding to the largest die-off in modern history. A combination of a bark beetle infestation and the ongoing drought are to blame. In addition to the environmental impact, there's another concern.

"The tree mortality in the central and southern Sierra is extreme," said Chief Ken Pimlott, director of California's Department of  Forestry and Fire Protection (CalFire), speaking on Take Two. "It's a slow moving disaster and it has the potential for large damaging fires."

In areas of extreme die-off, between 80 and 100 percent of trees are gone. "There's also a falling hazard right where people live" said Chief Pimlott, "on infrastructure, on roads. So we are extremely concerned about the public safety threat in these area."

In an effort to maintain safety, firefighters have been working all winter to clear debris, put fuel breaks in place and teach homeowners what they can do to better protect themselves. Fire teams are also using a variety of methods to dispose of the piles of wood created by the die-off, such as chipping and moving the materials to biomass facilities. Still, said Chief Pimlott, this is not enough.

"The challenge is that there's a significant amount of this material out there, more than we have capacity to move and to utilize in others ways," he said.

California has invested $5 million in tools to tackle the tree backlog, including the purchase of air-curtain burners, a dumpster-like container that incinerates wood at high temperatures. According to Chief Pimlott, the burners produce less ash and particulates than traditional open burning. Yet environmentalists have voiced concerns about the air-curtain burners and the potential impact on air quality, but for Chief Ken Pimlott, the alternative is far worse.

"If we don't dispose of this material, it will result in wild land fires," Pimlott said. "We've seen 100-thousand acre fires in the Sierra Nevada in the last several years and the emissions from those kinds of fires are exponential."