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NATURE
· Fire Forests
FIRST PEOPLES
· First Nations Basketry from the Dry Forests
HISTORY
· Revealing the Cariboo-Chilcotin
This is a link to a map of the forests of British Columbia with optional close-ups of Northeastern British Columbia, Cariboo-Chilcotin and Central Coast.

FOCUS  Cariboo-Chilcotin -- Dry Forest

Fire Forests
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This is an electron microscope photograph of an adult Mountain Pine Beetle.
Electron microscope picture of adult Mountain Pine Beetle. Canadian Forest Service.

Mountain Pine Beetle

The Mountain Pine Beetle (Dendroctonus ponderosae) is an insect less than a centimetre long that lives most of its life under the bark of pine trees, including Lodgepole, Ponderosa and Western White pines.

The beetle is native to western North America where it has been munching pines for millions of years. Normally it plays an important role in the life of a forest, attacking old or weakened trees and encouraging the development of new forests. But fire suppression has promoted the survival of forests full of old Lodgepole Pines and unusually warm, dry summers and mild winters have helped maintain large beetle populations. The result is an insect epidemic, especially in central British Columbia. The area attacked increased from about 800,000 hectares in 2001 to 4,000,000 hectares in 2003.

Image 1
This is an illustrated map showing the area attacked by Mountain Pine Beetle in British Columbia, with an option to zoom in.

Image 2
This is a photograph showing Mountain Pine Beetle larva that has tunneled into a tree, with an option to zoom in.

Image 3
This is a photograph of a tree trunk oozing pitch out of Mountain Pine Beetle entrance holes.

Image 4
This is a photograph of a male and female pair of Mountain Pine Beetles that have been pitched out of a tree.

Image 5
This is a photograph of a valley showing red coloured trees in the foreground that have been attacked by Mountain Pine Beetle.

Image 6
This is an aerial photograph of the pine forest in Western Chilcotin showing mostly pink-coloured trees that have been killed by Mountain Pine Beetle.

Photo viewer

During late summer, adults leave dead trees and attack living ones, releasing chemicals that attract more beetles. They bore through the bark to get at the phloem, the sweet juicy region that carries sugars from the leaves. Here, females lay eggs and the growing larvae feed, girdling the tree.

But trees have defenses. By oozing pitch out of the trunk, they may literally "pitch out" the beetles through their entrance holes.

Beetles carry the spores of Bluestain Fungus, spreading it from tree to tree. The fungus interrupts the flow of water to the leaves and reduces the action of the defensive pitch. The combined action of beetle feeding and fungal attack kills the tree, turning it red.

Beetle infestations have been recorded in B.C. since 1913. Large ones usually last a decade. They end when suitable trees have died, or when very cold weather kills the insects.

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