Pine beetles bore through lodgepole pine bark, laying eggs between the bark and wood. They cut off the flow of nutrients and produce a fungus that combats the tree’s defence mechanism and kills it.
The fungus stains the wood blue reducing its market value. Blue stained pine is sold under the "denim pine" brand. It has some advantageous tensile, social and aesthetic properties.
The market for lumber is saturated as infested forests are harvested. In a few years lumber will be in short supply. Clearcutting susceptible forests now will make the situation worse.
The impact of the pine beetle can be reduced by broadening forest biodiversity. Partial cutting and thinning maintains a vigorous forest and preserves many other attractive and beneficial forest qualities.
B.C. forests have been ravaged by the mountain pine beetle. Nothing foresters have done to fight the infestation has slowed the beetle's spread.
Global warming creates conditions in which the pine beetle thrive.
Alberta has mature lodgepole pine forests that are susceptible to forest fire and pine beetle, but trees are smaller and drier. Pine beetles normally don’t attack trees of 10 cm diameter or less.
The Alberta climate is cooler than B.C.. Beetles die in extreme cold.
Beetles fly and spread when blown by the wind.
Foresters combat beetles by burning infected trees.
Clearcutting opens the forest allowing beetles to spread further and faster.
The beetles are not happy to take the smaller trees that make up the forest in Kananaskis. The bugs can't survive on smaller trees. They may attack a few of them, but those trees can't sustain the beetle. The pine beetles won't kill all the other trees as clearcuting will and they won't kill the understory.
Those young trees will enjoy a surge of growth when the canopy of big old trees are gone. It will take years for those big trees to fall and during that time they'll help retain and recycle water. That's why it is far better to leave the trees.
They weren't able to stop the beetle in B.C. You can't. You can mitigate the damage, but this is a very visible manifestation of climate change. Cold kills the bugs. Our warm winters have allowed it to flourish. When you look at those alarming photos of vast expanses of red trees in B.C. - you're looking at global warming.