Stories tagged Dendroctunus

Nov
18
2008

Mountain pine beetle: download brochure by clicking on Forest Service
Mountain pine beetle: download brochure by clicking on Forest ServiceCourtesy US Forest Service

Why are all the trees dying?

Last summer I spent a week in Colorado and the Rocky Mountain National Park. One question was repeatedly being asked by visitors, "Why are all the trees dying?" In many places every lodgepole pine over five inches was dead as far as the eye could see. From the Mexican border all the way up into Canada millions and millions of acres of mountain pine forest are dead or dying.

Mountain Pine Beetles

A black, hard-shelled beetle called Dendroctunus, which means tree killer, drills through pine bark and lays its eggs in the sweet, rich cambium layer that provides nutrients to the tree. They also inject a fungus to stop the tree from moving sap, which could drown the larvae. Officials claim that this is the largest known insect infestation in the history of North America.

Why is this happening now?

Mountain Pine Beetles used to be mostly killed off by -30 to -40 degree below temperatures. That has not happened for about ten years. Eight years of drought also has weakened the trees and their ability to flush out invaders with sap flow.

Dead trees create problems

Dead trees will eventually fall down. This means removing millions of trees near homes and along roads and trails.

At Vail Ski Resort, for example, which has been particularly hard hit, workers have removed thousands of dead trees and planted new ones. In Yellowstone the beetles are killing the white-barked pine trees, which grow nuts rich in fat that are critical to grizzly bears in the fall. In Colorado and Wyoming, officials have closed 38 campgrounds for fear trees could fall on campers. They have reopened all but 14.

Wildfire is the biggest threat. Many homes and communities are surrounded by dry, dead trees. The Forest Service and logging companies are clear-cutting “defensible space” so firefighters have a place to fight fires. The amount of dead wood is overwhelming, though. Hopefully entrepreneurs will find ways to use it. I am afraid that what is left behind is not going to be very "scenic" for a long time.

Learn more about the mountain pine beetle infestation

Source article: New York Times
Video: Americas disappearing forests
US Forest Service: Regional bark beetle information
Denver Post editorial by Merrill Kaufmann: Battling the pine beetle epidemic
32 page teacher packet (pdf): Mountain Pine Beetle Mania