Bark beetles may add to intensity of wildfires

U.S. Forest Service

(CBS/AP) Scientists are using computer models to gain a better understanding of what makes wildfire go. They're working as firefighters toil on steep mountainsides to put out more than a dozen new blazes in what has already become a vicious summer of destruction in the West.

Experts agree: Dry conditions and strong winds are driving this year's super fires.

It gets more complicated when researchers add to their formulas the devastation caused during the last 15 years by bark beetles. The tiny insects have devoured more than 40 million acres of the nation's forests. Some research suggests fire burns hotter and more quickly in beetle-affected areas, while other research indicates that other conditions complicate how fire relates to the beetle problem.

"We've always had bark-beetle infestations, but we've never had anything that's been so widespread and spread so quickly," Tom Tidwell, chief of the U.S. Forest Service, told the Los Angeles Times. "The only place it's really starting to slow down is just where we're starting to run out of trees."

The relationship between beetles and the intensity of fires is anything but simple. There are approximately fifteen different species of beetle in the West, and the type of beetle in a given area will determine what trees are spared and which come under attack.

One theory is that fires burn fiercest when beetle-killed trees keep their red needles. These needles act as quick fuel to a fire, spreading the devestation.

Annual aerial surveys done by the U.S. Forest Service show the number of new acres being attacked by beetles has actually decreased overall from a peak of 8.8 million in 2009 to 3.8 million last year. However, there are pockets in some parts of the West where beetle infestations continue to accelerate.