Posted by Sherman in Idaho [72.47.153.28] on Tuesday, June 17, 2014 at 15:58:41 :
In Reply to: It's not going to be a bad year out West...... posted by gmharris [71.105.36.254] on Tuesday, June 17, 2014 at 11:43:27 :
If by "forests" you mean lodgepole pine forests, they're dying because they're simply too old. In the days before fire suppression, healthy lodgepole forests burned every 20 years on the average. Fire, not freezing, is God's way of controlling bark beetles. With fire suppression, most of the lodgepole forests are growing up with other species like grand fir, which take over as the lodgepoles naturally die. A 50 year old lodgepole is near death even without bark beetles.
This whole business about the forests dying because global warming has made the winters too mild to kill the bark beetles is just not biologically accurate. Yes, in the interior of British Columbia it used to get cold enough to freeze the bugs, but that requires 50 below zero fairly early in the fall before the grubs have had time to get toughened up for the winter. I doubt it's ever been cold enough in the lower 48 to kill the grubs.
Look at a young lodgepole forest, one that was burned or logged less than 20 years ago, and you won't see any beetle damage. The problem is that people don't want to let lodgepole forests burn any more, which means the beetles can keep chewing until the pines re all gone and the forest has changed to entirely different species. Which, incidentally are species that will be exterminated rather than rejuvenated by the next fire that does come through.
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