Beetles still spreading fast

SUMMIT COUNTY - Mountain pine beetles are still finding new trees to kill at an unprecedented rate in local forests, with no signs that the infestation will slow down any time soon.

"We're just looking for some really cold weather," said Sandy Briggs, of the local pine beetle task force, referring to a hoped-for cold snap that might kill some of the larvae in the trees and limit the damage.

Briggs said the outlook is still that the bugs will kill about 90 percent of the lodgepole trees in the area, decimating the predominant tree species at the mid-elevations in Summit County.

Reports from Forest Service field rangers and from private forestry companies are that the beetles had another strong flight this summer, leaving behind the old host trees and spreading wildly to new targets.

"I was working on a trail above Wildernest, and there are new hits everywhere," Briggs said. Every green tree that hadn't previously been hit by the beetles showed signs of an attack from this summer, he said.

"We're worried that when the host trees decline they will hit spruce trees," Briggs said.

U.S. Forest Service Dillon District Ranger Rick Newton said the beetles do look for other trees when they run out of lodgepoles. But they won't devastate spruce forests in the same way they did in lodgepole stands, he added.

"It's a desperation move," Newton said. "There will be some collateral damage but it won't have an effect on a landscape basis," Newton said. The pine beetles can attack spruce trees and inoculate them with the deadly blue-stain fungus, but they can't reproduce in spruce trees, Newton explained.

The number of infested trees continues to grow exponentially in the county, Newton said. There aren't any exact figures on how many trees have already been killed percentage-wise, but in the northern part of the county, the mortality rate may have already reached the 90 percent mark, Newton said. The southern part of the county may reach that level by this time next year, he added.

"We fully expect to lose between 90 and 95 percent of the mature lodgepoles," he said.

Newton said the Forest Service has made big progress on finalizing logging contracts to mitigate the fire danger near local neighborhoods. The timber sale covering the area between Silverthorne and Frisco, on both sides of I-70, is done, and work will begin this fall, he said.

"People will start to see some significant physical changes as part of the response (to the beetles)" Newton said.

Along with the potential wildfire danger, another huge concern is the impact to local watersheds.

Briggs said the change in the structure of the forest is bound to have significant effect on snowpack and runoff.

"The lack of shade means the snow will melt much faster under direct sunlight, and as the trees fall down, the wind will also play more of a role in transporting snow. Peak runoff could come much earlier in the spring and at higher levels, leading to erosion issues, Briggs explained.

On the other side of the coin, there won't be as much water loss through transpiration and evaporation, and direct consumption from the soil by trees, he said, adding that forest scientists are still trying to evaluate exactly what the watershed impacts will be.



Bob Berwyn can be reached at (970) 331-5996, or at bberwyn@summitdaily.com.