Aspen beetle battle already lost?
The Aspen Times
ASPEN, Colorado – The tactics designed to slow the spread of mountain pine beetles on a patch of Smuggler Mountain will probably just delay the inevitable and fail to preserve lodgepole pine trees, according to beetle experts.
Scientists with the U.S. Forest Service and the Wilderness Society said using a chemical called Verbenone on live trees to try to ward off beetle attacks is a short-term solution at best. Use of Verbenone alone won’t protect uninfested lodgepole pine trees, said Jan Burke, a silviculturist with the White River National Forest.
A nonprofit group called For the Forest believes the outbreak can be slowed by removing brood trees and treating live lodgepole pine trees with Verbenone. The group is splitting the bill with the city of Aspen and Pitkin County on an experiment to save some lodgepole on 120 acres of open space on Smuggler Mountain. The first step will be removing at least 125 trees already infested with mountain pine beetles. The second plan of attack is to staple pouches of Verbenone to tree trunks in the targeted area. For the Forest said the Verbenone treatment might need to be applied annually for five years at a cost of $40,000 per year. For the Forest said Verbenone has been used effectively in other areas suffering an outbreak.
Verbenone is designed to mimic pheromones produced by the mountain pine beetle. The pheromone is used to signal that there is no vacancy at a tree under attack by female beetles.
Greg Aplet, a senior forest scientist with the Wilderness Society’s office in Denver, said there are already so many pheromones “floating” around in forests that their effectiveness to protect trees is questionable. Pheromones are only short-term solutions, he said. It would be more effective to use insecticidal applications to individual trees each year, he said.
Burke said the Forest Service uses an insecticide called Sevin rather than Verbenone on lodgepoles deemed important to save, like some in campgrounds.
Sloan Shoemaker, executive director of the Wilderness Workshop, the Roaring Fork Valley’s oldest conservation group, is a member of a task force that has intensively studied the bark beetle epidemic in Colorado. He is among conservationists who will testify this month before a U.S. House subcommittee that is exploring national policy on management of beetle-ravaged forests.
Shoemaker said the removal of dead and dying trees on the Smuggler Mountain open space is a “good thing” while the use of Verbenone is essentially useless. The treated lodgepoles remain healthy and green and stick out among stands of infested ones that turn red and die.
“They’re like ice cream to the beetles and eventually they’ll be overwhelmed,” Shoemaker said of the treated trees.
Burke said virtually all mature lodgepole pines appear doomed from this infestation. It’s possible that use of Verbenone could be a “stop-gap measure” that would preserve some mature lodgepoles if the infestation collapses within the next few years. But the chances don’t appear good because the infestation will only end when the beetles “run out of food,” she said.
“I’m not saying lay down and die,” Burke stressed. But she thinks money is better invested on steps like transplanting saplings in areas hit hard by beetles.
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