Piñon, pine or spruce - beetles by many names deadly for trees

Jim Erickson, Rocky Mountain News

Published September 11, 2006 at midnight

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While the causes of the aspen die-off remain unclear, the culprit behind the ongoing decimation of Colorado's conifer forests is no mystery: It's the beetles.

Over the past decade, various beetles have killed more than 10 million conifers in Colorado forests, said Bob Cain, a U.S. Forest Service entomologist.

The combination of aging, unnaturally dense forests and several years of severe drought allowed the mountain pine beetle epidemic to reach record levels in lodgepole and ponderosa pine forests.

At the same time, bugs have feasted on other pines, spruce and fir trees across the state.

According to federal and state foresters:

• Mountain pine beetles attacked 1.3 million trees on 500,000 acres last year in the state, primarily in lodgepole pine forests of north-central Colorado. Ponderosa pine forests also experienced outbreaks.

• Piñon ips beetles killed more than 9 million Colorado piñon pines, mainly in the southwestern and southern forests, in an epidemic that peaked two years ago.

• Western balsam bark beetles and root diseases killed more than 600,000 subalpine fir trees in the state last year.

• Spruce beetles infested 1.2 million trees on 119,000 acres last year and appear poised to launch the next big bark beetle epidemic, according to the Colorado Forestry Advisory Board.

Last week in Denver, the U.S. Forest Service announced a four-state initiative to address the bark-beetle problem. In Colorado, the counties to be targeted are Eagle, Grand, Jackson, Summit and Jefferson.

The initiative could bring millions of dollars in federal funds to the state.

Hard-hit Colorado ski areas already have shelled out big bucks to deal with the epidemic. The town of Winter Park and the resort's owner, Intrawest Corp., spent roughly $800,000 last year. Keystone ski resort and towns such as Frisco have spent more than $300,000.

The Beaver Creek, Breckenridge, Copper Mountain, Keystone, SolVista, Steamboat, Vail and Winter Park ski resorts are suffering bark beetle epidemics.

Arapahoe Basin, Aspen Highlands, Aspen Mountain, Buttermilk, Eldora, Howelson Hill, Loveland, Ski Cooper and Snowmass risk losing substantial numbers of lodgepole pine and spruce trees.

There is no practical way to stop a large-scale mountain pine beetle epidemic once it has begun, according to foresters.

But several tools are being used across the state to reduce damage in and around high-value locations such as mountain communities, ski areas and campgrounds.

One is preventive insecticide spraying of trees, which is costly. Another is the removal of infested green trees, a technique sometimes called sanitation.

Standing dead trees also are being cut and removed. It helps reduce the wildfire risk and can provide wood products for industry.

In some parts of the state, dense stands are being thinned to reduce competition among the trees for water, nutrients and sun. Thinning can enhance the vigor of the remaining trees so they're better able to withstand insect attacks, said Ingrid Aguayo, a Colorado State Forest Service entomologist.

In the forests near Steamboat Springs, researchers experimented with chemical attractants called pheromones.

Pheromone traps are placed within a stand of trees that have been sprayed with protective insecticides. Beetles are lured to the sprayed trees and are killed when they munch on them.

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