BILLINGS – Mountain pine beetle activity is declining in Montana, a U.S. Forest Service official says.
The finding is the result of aerial surveys last year and analyzed in the 2011 Montana Forest Insect and Disease Conditions report prepared by the Forest Service and state Department of Natural Resources and Conservation.
But the report also found emerging problems with western spruce budworm and pine butterfly.
The report covers about 20.5 million forested acres in Montana, including federal, state and private lands. The survey found beetle-killed trees on more than a million acres, but that’s down from 2 million in 2010 and 3.6 million in 2009.
“We are seeing a continued decline in mountain pine beetle activity in many areas across the state, indicating the epidemic may have reached its peak,” said Gregg DeNitto, a Forest Service pathologist and leader of the Forest Service’s Forest Health Protection office in Missoula.
The Billings Gazette reports that the aerial survey also found 1.2 million acres defoliated by the western spruce budworm. That’s up from about 326,000 acres in 2010, but less than the 2.6 million acres in 2009. Officials said the trees usually survive, but are severely stressed by the defoliation.
Budworms target Douglas fir, spruce and true fir trees.
The budworm attacks, the survey found, were concentrated in the northwestern Montana counties of Lincoln, Flathead and Sanders,
Officials said the Douglas-fir tussock moth and pine butterfly are becoming more active in the western part of the state. Pine butterfly, which attack and defoliate mature ponderosa pine, are at outbreak levels in the Bitterroot Valley, the report said.