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.

Photo by Chris Welsch

Rust colored lodgepoles, doomed by pine beetles, ring a meadow on the Green Mountain Trail loop in Rocky Mountain National Park.

Colorado’s Rocky Mountain National Park is known for its spectacular alpine highway, Trail Ridge Road, which rises to more than 12,000 feet above sea level as it crosses the tundra, high above the treeline. That treeline is in big trouble. I went to the park on Saturday — it’s less than an hour away from Boulder — to take a long hike in the western part of the park. As I drove through the eastern side of the park, I caught glimpses of the mature lodgepole pine forests that are characteristic on the slopes of the park’s dramatic mountains. Symmetrical and tightly ranked, the trees form a geometric pattern of deep green that pleases the eye. On the western side of the park, the same kind of pattern could be seen but in a deep shade of rust. The pine beetle epidemic is deforesting the park with amazing speed. Whole mountainsides are red with dying pines. As of 2007, 1.5 million acres of Colorado’s pine forests were lost to the epidemic. Experts say that in 5 years, most of the lodgepoles in the state will be gone. Warmer winters have allowed the beetles to migrate north. There’s no effective or affordable way to stop them. This is a dramatic example of how the landscapes we love are being dramatically altered by climate change. It’ll be interesting to see how the mountain eco-system regenerates in coming years. Like the blowdown in the BWCA (but on a much larger scale), the repercussions (fires, erosion, etc.) will be coming for years.