The mountain pine beetle epidemic is going to change the way Colorado looks for decades, if not longer. The Colorado Forest Service (not known for excitability in these matters) predicts that every mature lodgepole pine in the state will be dead within five years. If you’ve been in Rocky Mountain National Park, you know that lodgepoles are an iconoc part of the landscape.

I attended a talk by University of Colorado professor Jeffry Mitton, an expert on pine beetles. The auditorium at the Boulder Public Library was nearly full. He said that a square that is 1,000 miles on a side, stretching from Colorado to Alberta to British Columbia to Northern California, is under epidemic conditions; within this range, mountain pine beetles are devastating the lodgepole pine forests. “We’re taking more than 1 million square miles of beetle infestation,” he said. “This thing is huge.”

He added some insights to the situation that merit sharing. One, mountain pine beetles are endemic in the Rockies. They’ve been attacking pines for millions of years, he said. “They’re part of the forest ecology.” Two, while climate change is a factor, there are other reasons the pine beetles are so successful at killing off trees right now.

Mitton showed historical photos from the turn of the last century showing a much sparser looking lodgepole landscape. “Once these areas were settled, forest fires pretty much stopped,” he said. That led to thicker forests. The lodgepole pine’s natural defense against beetles is to “pitch them out,” Mitton said. The beetle bore holes into the bark and begin carving galleries in the phloem, the material between the bark and wood that is essentially the vascular system of the tree. Healthy trees kill or force out the beetles by flooding them with pine pitch. But with a denser forest, each tree gets less water, and is thus less capable of defending itself. Drought conditions and hot summers, combined with warmer winters that make life easier on the beetles, have led to this epidemic.

One small bright note: The beetles can’t thrive in trees smaller than 7 inches in diameter. Therefore, once this generation of lodgepoles is gone, the beetle population will crash, and the younger pines will get a chance to fill in behind their dead relatives. For more on how the tiny beetles kill such big trees, check out this link.

P.S., this particular brand of beetles won’t be coming to Minnesota, because we don’t have lodgepole pines. But ash borers and other pests are posing a similar menace to our forests.

This entry was posted on Monday, September 15th, 2008 at 9:55 pm and is filed under Boulder, environmental, national parks. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed.