DENVER – Colorado can expect bigger, hotter wildfires that burn longer as trees killed by pine beetles tip over, foresters said Wednesday.
The spruce beetle outbreak in southern Colorado nearly doubled in size last year to 208,000 acres, according to the 2010 Report on the Health of Colorado’s Forests. The outbreak is centered on the high-altitude forests north of Pagosa Springs.
Farther north, pine beetles have torn through a 180-mile-by-140-mile swath of lodgepole pines, said Tony Dixon, the Forest Service’s deputy regional forester for the Rocky Mountains.
The dead tree trunks left over after the multiple bug outbreaks are quickly becoming a prime concern for foresters.
An estimated 100,000 dead trees fall in the pine beetle zone every day, Dixon said.
A wildfire in the dead zone might be too dangerous to fight because firefighters might not be able to go into the area because of the hazard of falling trees, said State Forester Jeff Jahnke.
“If we get a fire in that kind of stuff and the wind’s blowing 20 to 30 miles per hour, we may not be able to suppress that fire,” Jahnke said.
Air tankers aren’t effective against close-to-the-ground fires in dead timber, Dixon said.
“We’re probably going to have to allow these fires to grow much larger than we’re accustomed to,” Dixon said.
On the bright side for Southwest Colorado, aspen trees are doing better.
Sudden aspen decline has afflicted some of the state’s most scenic stands of aspen trees, but Jahnke thinks two good years of moisture has helped halt the decline.
A 2009 aerial survey counted 342,000 acres of dead aspen, but the afflicted acreage dropped to 190,000 in last year’s survey.
Jahnke and Dixon presented the forest-health report to legislators Wednesday morning.