The Pine Beetle Blight and the Loss of North America’s Forests: The Link to Global Warming

It may seem like the news has lately portrayed one major culprit of destroying forests: fires.  But a less obvious and just as dangerous offender is the pine beetle. Long a pest to forests, the beetles inhabit trees and kill them in the end.  But cold temperatures have always kept these insects at bay for enough of the year that the forests would have time to re-grow and continue to prosper.  Now with global temperatures warming up the forests aren’t experiencing these cold temperatures and thus the pine beetle is surviving at a time when its population typically dies.  This has resulted in what is thought to be the largest forest insect blight in North America.  Losses in the millions of acres are occurring across parts of the west in what is looking more and more like a pine beetle epidemic.

The mountain pine beetle is found in the forests of western North America.  They are spread between the forests of New Mexico up into the forests of British Columbia.  Typically the pine beetle inhabits old and diseased trees which helps make way for more of the younger trees in a forest.  The beetles lay their eggs under the bark of the tree and inject a fungus into the tree which prevents the tree from fighting off the beetles with tree pitch flow.  This inhabiting of trees didn’t use to be a problem since certain weather conditions controlled the beetles and kept them from moving on to young, healthy trees.  Cold winters killed off most of the beetle population and cool summers kept them from reproducing too quickly.  The higher year-round temperatures caused by global warming is creating a two-fold problem though.  Beetles are reproducing faster due to the dryer, hotter summers and beetles aren’t dying off in the winter season due to warmer temperatures.  This has resulted in extreme forest insect blight.  Already millions of acres have been lost in Montana, Colorado, Wyoming, and British Columbia.

While the loss of forests in itself is devastating what is more devastating is its effect on global warming.   The areas in which there used to be live forests are now acting as a carbon source rather than the sinks they were.  The dead trees left behind by the beetle blight emit carbon dioxide; 50% more carbon dioxide than if the trees had burned.

Stopping the pine beetle appears to be the only solution to our loss of forests since the cold temperatures that used to subdue these insects won’t be coming back.   While there are management techniques for typical pine beetle outbreaks this current outbreak is much larger than what those techniques would work for.  Thus many state governments are simply trying to keep the forests from becoming a potential fire hazard by conducting “fuel management activities”;essentially removing hazardous trees.  In small areas other techniques might be used such as pheromone baiting and removal of infested trees but without a large scale plan the beetle will simply continue its destruction.  The only other option is to simply wait until there aren’t any more large trees for the beetles to feed on and let the population die out.  The forests of North America are one of the earth’s greatest assets against global warming.  Without them our world will be that much closer to succumbing to the unstable future awaiting us.

Photo Credit: flickr.com/photos/mikelehen/3846829527/sizes/s/in/photostream/

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