Beetles A Major Factor In Lake Arrowhead Fire

BERKELEY, Calif., Oct. 24, 2007 (KGO) (KGO) -- The conditions that make for a catastrophic fire vary from place to place. For instance, in the Oakland Hills fire of 1991, the heavy concentration of eucalyptus trees contributed to the totality of the destruction. In Lake Arrowhead, a tiny bug is a major factor and that same pest could play a major role in future fires in the East Bay hills.

Blame the beetle, at least in part, for the extent of the fire damage around Lake Arrowhead, where hundreds of homes have burned since Monday.

The inferno has been fueled by huge stands of beetle-infested pine trees -- dead wood.

"That's the insect that kills Monterey pine," says David Wood, Ph.D., a U.C. Berkeley researcher.

They are the same tiny culprits at work in pine trees all over the Bay Area, including one at U.C. Berkeley.

"That's what we call the top-kill stage. So the next stage is that the tree dies."

And that's where Professor David Wood studies the relationship among beetles, trees and fire.

"We have the potential here for similar kinds of fires," explains Wood.

Like at Lake Arrowhead, in the Bay Area bark beetles have killed countless Monterey pines including in the East Bay hills where pines are mixed in with highly-combustible eucalyptus. With 16 years of re-growth, the vegetation and fuel mix in the Oakland Hills now looks a lot like it did before the fire of 1991.

"It's bringing back the fire danger because the eucalyptus has sprouted from the stumps and the Monterey pines that were big trees up there have come back from seeds," says Wood.

The conditions exist despite efforts to clear away the most dangerous vegetation and create fire breaks in key places.

But once the high winds start blowing, in Southern California they're called Santa Ana winds, all bets are off when it comes to vegetation management to prevent fire.

"Basically, once those winds get going, and if there's an ignition and we get a fire during those winds, the vegetation characteristics do not play as a strong a role," Say Max Moritz, Ph.D., a U.C. Berkeley wildfire specialist.

In short, trees or not, almost everything in the path of a wind-driven fire like the one in Southern California will burn.

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