COEUR D’ALENE, Idaho – The region’s largest infestation of mountain pine beetles in 20 years has hit more than a million acres of forests in northern Idaho and Montana, while 2.5 million acres in Washington face disease and insect problems.
Recent flight surveys by the U.S. Forest Service and state forest management agencies found that years of drought have left forests in the Northwest vulnerable.
The surveys found that 1.1 million acres of forest came under attack by mountain pine beetles in northern Idaho and Montana in 2005, an increase from 675,000 acres the year before.
The Washington state Department of Natural Resources reported that mountain pine beetles were at epidemic levels, with a 28 percent increase to 554,000 acres. Overall, insect and disease problems are present in 2.5 million of Washington’s 21 million acres of forest, up from 1.9 million acres the previous year.
Karen Ripley, an entomologist with the Department of Natural Resources, said last year’s abundant rain and this winter’s good snowpack will reduce stress on forests this summer.
But she said it would take several years of normal moisture for forests to return to good health. She said fire suppression combined with a lack of logging means nature will find a way to remove trees.
“Nature’s way is to have some of the beetles kill some of the trees,” Ripley told The Spokesman-Review newspaper. “That relieves some of the competition. We’ve got a lot of stressed trees out there now, and they’re easy pickings.”
In the Bitterroot Mountains along the Montana-Idaho border, the beetles have left orange patches of dead trees, said Tom Martin, a silviculturist with the Idaho Panhandle National Forest.
He said the Forest Service wants to thin about 500 acres in the Upper St. Joe River area of Idaho to reduce the infestation. The agency, he said, has also spent $40,000 to protect lodgepole pine at the Lookout Pass Ski Area with pheromone treatments. The treatments fool beetles into thinking a tree has already been attacked.
“What we’re trying to do is weather the storm,” said Martin.
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