In a move to keep Bald Mountain from becoming even more true to its name, the U.S. Forest Service will likely move ahead with a plan to prevent further infestation by the Douglas fir bark beetle.
Ketchum District Ranger Kurt Nelson said a U.S. Department of Agriculture grant is in place to help fund application of the pheromone methylcyclohexenone, known as MCH.
The pheromone is naturally produced by the beetles to let other beetles know that there is no more room in a tree, thereby preventing overpopulation in a single tree. By replicating MCH and attaching it to trees that have yet to be infested, the Forest Service can trick beetles into staying away from certain areas and keep them hunting elsewhere for trees to infest.
Last spring, the Forest Service attempted to stanch the beetles' spread by stapling small bags of MCH to trees along Guyer Ridge, on the north side of the mountain. About 1,250 pouches were stretched out in a strip about 250 yards wide from close to the top of the mountain to the Warm Springs parking lot.
The deployment did not prove to be impenetrable, though, and the beetles found their way over the defensive line and into trees bordering the upper sections of International, Warm Springs, Limelight and Picabo's Street runs.
This time, the Forest Service is proposing a new tactic that involves spreading tiny plastic flakes embedded with the MCH pheromone next spring, before the beetles emerge in June and look for new trees.
Nelson said the proposal's public comment period, which closed Jan. 8, rendered about 10 comments, all of which were positive, albeit with concern about how the chips could affect other species.
Nelson said that as the pheromone is a naturally occurring chemical created by the beetles, he does not anticipate any problems for other animals.
"I'm pretty optimistic that this project will be moving forward," he said.
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However, Nelson said more environmental impact analysis has to be completed before the project can be approved, which could happen in mid-February.
The flakes, measuring 3 millimeters across, would be applied by helicopter over a 4,000-acre area on Bald Mountain, about half of which would be within the ski area. By using a helicopter, the Forest Service would be able to cover an area in a single day that would take an entire summer on foot.
Though Nelson declined to give the exact amount of the grant, as the project has yet to go through the bidding process, he said he expected it to cost between $25 to $50 per acre.
The chips would likely be spread in late April or mid-May, then again at the end of July or early August.
Without any preventative action, trees along Bald Mountain, beginning with the northern side, would begin to turn red and then brown throughout the summer.
The problem was worsened by the Castle Rock Fire, which swept through the eastern Smoky Mountains in summer 2007. The fire helped augment a dramatic rise in the population of the Douglas fir bark beetle, which is now infesting its namesake trees throughout thousands of scorched acres and threatening healthy trees as well.
While healthy trees are able to produce enough sap to either drown the beetles or force them from beneath the bark, trees damaged by fire or drought don't have that capability. The weakened trees are unable to protect themselves as the beetles burrow into the inner bark and construct "galleries" to lay their eggs. When the eggs hatch, the larvae feed on a perpendicular plane so that if enough larvae are present, they will prevent the flow of water up from the roots and nutrients down from the needles. Eventually, that leads to the death of the tree.
Jon Duval: jduval@mtexpress.com
