Pesticide to be used against pine beetle
June 10, 2009
SUSAN GALLAGHER Associated Press Writer HELENA
A pesticide used widely in agriculture will be sprayed in parts of western Montana's national forests to fight new attacks by beetles that have killed vast swaths of pine trees, turning them a shade of red. Trees in designated Helena National Forest campgrounds and at trailheads will be sprayed with carbaryl early next week if the weather permits, forest officials said Tuesday. The insecticide also will be used in the Beaverhead-Deerlodge, the Lewis and Clark and the Gallatin national forests, said Gregg DeNitto, group leader for forest-health protection at the Forest Service regional office in Missoula. Carbaryl, with trade names that include Sevin, will be sprayed from the ground to soak tree trunks. Officials with the Helena forest said public-use areas will be closed for 24 hours before spraying and for 48 hours afterward. Carbaryl dries quickly, DeNitto said. "It is used on trees that have not been attacked so we can keep them from being attacked," he said. Carbaryl is toxic to fish and aquatic insects, and the Forest Service does not plan to use it near water. One alternative is a pheromone treatment in pouches stapled to trees. That treatment is less effective against pine beetles than is carbaryl, DeNitto said. Janet Ellis of the Montana Audubon staff said some of the bird organization's members have expressed concern about forest use of carbaryl. Federal tests that found it "practically nontoxic to birds" involved larger birds such as mallards, but there are anecdotal reports of harm to small birds, Ellis said. "It does seem to affect smaller birds, but no one's really done the work to know," she said. Aerial surveys last year found about 1.8 million acres of Montana attacked by beetles, mostly the mountain pine beetle, DeNitto said. The Forest Service estimated some 17 Million trees were on those lands. The southwestern part of the state has been hit particularly hard, DeNitto said. Colorado followed Montana with 1.6 million acres infested, Idaho had 1.3 million acres and Wyoming 1.2 million, he said. Other insects can cause trees to redden, but most of the red trees evident in Montana have been hit by pine beetles, DeNitto said. The insect's attacks in large numbers are cyclical. "In any particular location they tend to run out for five to seven years," DeNitto said. "How long it (the infestation) will last we're not exactly certain. We know that in some areas it's in decline, essentially because it does not have more trees to attack," but beetles continue to cause damage in places previously unaffected. The dead trees still have some value in the woodproducts industry, but "the supply way outstrips the demand," DeNitto said. They increase wildfire hazard in the first few years after dying, he said, but the fire risk drops after the trees' needles fall off. As the trees later deteriorate, their woody debris accumulating on the ground can increase fire severity, DeNitto said. The risk that beetle-killed trees would fall on people led the Forest Service to recently close Park Lake, a popular recreation area near Helena, perhaps for the entire summer. During the next few months, the Forest Service plans to remove about 5,000 dead and dying trees on 30 acres in the lake area. Last fall, a state forestry official told the Montana Land Board that insects lethal to trees had attacked upward of 32,000 acres of state-owned land managed as a trust for the public schools, and that insects posed an "elevated risk" for more state property. Drought, mild winters, wildfire suppression and forests crowded with too many trees support insects, entomologist Amy Gannon of the Montana Forest Management Bureau told the board. Near Missoula, carbaryl has been put on some state trees that are used for seed, Sarah Lyngholm, state forest product sales supervisor, said Tuesday. Overall, state officials strive for forest health by promoting a mix of tree species and by managing tree density, she said. Managing density includes thinning trees. The Forest Service has been criticized for not removing enough trees and has been challenged in court over proposed logging that critics said jeopardized wildlife habitat. If we had taken a proactive stance in managing our forests we wouldn't be in the shape we're in with the bugs, but it's not something you stop," said Chuck Roady, president of the Montana Wood Products Association. "There are things that trigger them into epidemic proportions." Roady manages F.H. Stoltze Land & Lumber near Columbia Falls and said mountain pine beetles hit the company's timberlands years ago. In northwestern Montana on this side of the (Continental) Divide, we went through it in the '80s," Roady said. "We've been there and done that."