Posted on Sun, Mar. 05, 2006

ENVIRONMENT

Beetles dismantling pine trees like wildfire

Thanks in part to warmer winters, a tree-killing beetle is attacking Canada's lush forestry and hurting businesses.

BY DOUG STRUCK
Washington Post Service

Millions of acres of Canada's lush green forests are turning red in spasms of death. A voracious beetle is killing more trees than wildfires or logging.

The mountain pine beetle has devastated swaths of lodgepole pines, reshaping the future of the forest and the communities in it.

Scientists fear the beetle will sweep across the northern continent into areas where winters now are comparatively mild. Officials in Alberta are setting fires and felling thousands of trees in an attempt to keep the beetle at bay.

The Canadian Forest Service calls it the largest known insect infestation in North American history.

U.S. Forest Service officials say they are watching warily. The United States is less vulnerable because it lacks the seamless forest of lodgepole pines that are a highway for the beetle in Canada.

In Canada, where the beetle's favored lodgepole pine thrives, it has been controlled by winters with early cold snaps or long killing spells of 20 degrees below zero. But for more than a decade the weather here has not been cold enough for long enough to kill the beetle.

Scientists with the Canadian Forest Service say the average temperature of winters here has risen by more than 4 degrees in the last century.

The result is a swarm of beetles that has grown exponentially in the past six years. The advance is marked by broad swaths of rust-red forest, the color pines turn before they drop all their needles to become ghostly grey skeletons.

In an attack played out millions of times over, a female beetle no bigger than a rice grain finds an older lodgepole pine and drills inside the bark. It eats a channel straight up the tree, laying eggs as it goes. The tree fights back. It pumps sap toward the bug and the new larvae, enveloping them in the sticky substance. The tree tries to eject its captives through a small chute in the bark.

Countering, the beetle sends out a call for reinforcements. A fungus on the beetle, called the blue stain fungus, works into the living wood, strangling its water flow. The larvae begin eating at right angles to the original channel, crossing channels made by other beetles. The pine is doomed. As it slowly dies, the larvae remain protected over the winter.

At the province's Ministry of Forests and Range in Quesnel, forestry officer Pelchat saw the beetle expansion coming as ''a silent forest fire.'' He and his colleagues launched an offensive to try to stop the invasion, all the while hoping for cold temperatures. But the deep freeze never came.

Pelchat is now spending his time replanting. A mature pine forest takes 70 years to grow.

Meanwhile, the beetle is moving eastward. It has breached the natural wall of the Rocky Mountains in places, and is within striking distance of the vast Northern Boreal Forest that reaches to the eastern seaboard.