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For the week of Mar. 8 through Mar. 14, 2000

Silent killer invades SNRA

Express Staff Writer

Mountain Pine Beetle(Picture courtesy U.S. Forest Service)

A silent killer is working its way through the Salmon River canyon in the Sawtooth National Recreation Area (SNRA).

Its name is the mountain pine beetle, and it’s attacking the area’s lodgepole pine trees.

"The beetles always just sort of bounce around," Sawtooth National Forest timber program manager Jim Rineholt said in an interview Monday. "They’re always out there. They just move from pocket to pocket, but down in the canyon, there, they’ve really just blown up."

If all goes as planned this spring, SNRA timber managers will cut down approximately 600 trees in the Salmon River canyon downstream from Stanley and spray many more with an insecticide in an effort to curb the beetles’ invasion. Efforts could begin in April or May.

The Forest Service is leaning toward a categorical exclusion from environmental laws for the anti-beetle projects, and biological assessments are underway. There was a public comment period that concluded late in February, but comments will still be accepted.

Spraying will probably be done in the Redfish Lake area as well, Rineholt said.

"The bugs are in there," he said of Redfish. "We’ve proposed to spray approximately 1,500 trees around Redfish and 500 in the canyon."

The idea, Rineholt said in a Monday interview, is to protect the Salmon River, River Side, Mormon Bend and Redfish Lake campgrounds, as well as older, landmark trees.

"We’re trying to save the bigger, more beautiful trees that are left," Rineholt said. "When [the beetles] enter a developed site, [they] can wreak havoc. They can easily destroy 80 percent of the trees."

Rineholt estimated that 60 to 70 percent of the lodgepole pine trees in the Salmon River campground are infected by beetles or are already dead.

Mountain pine beetles are about the size of the end of a matchstick, he said.

According to information contained in a brochure distributed by the Forest Service, the bugs feed on a layer of tree immediately below the bark. There they also lay their eggs, and when larvae hatch, they, too, feed on the same layer. The feeding eventually kills the tree.

The beetles usually take one year to complete a life cycle. Cold temperatures, however, can hinder the beetles’ reproduction rate.

Mountain pine beetles are one breed of several bugs that attack Western coniferous forests. They usually infest whitebark and lodgepole pine trees. Lodgepoles generally grow in the valleys while whitebark grow at higher elevations, Rineholt said.

Douglas fir, which grow on slopes at middle elevations in the SNRA, have a beetle all their own called the Douglas fir beetle, which also has found a home in the SNRA.

The insecticide that will be used on the trees, called Carboryl, is commonly used on crops in the U.S. It is highly toxic to invertebrates and moderately toxic to fish.

For those reasons, the insecticide’s use must be very closely regulated.

There are some Douglas fir beetles on the northern edges of the Ketchum Ranger District and out Warm Springs Creek, but no significant signs of mountain pine beetles in the Wood River Valley.

For more information, call SNRA headquarters at 727-5000.


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