Sunday, November 27, 2011

Bugs, fire, politics threaten western Montana forests

Rob Chaney in the Missoulian (Montana): Three things will combine to radically transform Montana forests in the next 50 years: bugs, fire and politics.

Mountain pine beetles have killed millions of acres of lodgepole pine trees. Those dead stands, combined with a progressively drier climate, will likely burn in wilder, more intense fashion. The biological aftermath should bring a wider mix of tree species, open areas and wildlife habitat, according to new computer models.

How humans tinker with that progression remains a wildcard. During this month's Society for Conservation Biology research symposium at the University of Montana, several scientists demonstrated a technique called landscape simulation modeling. They've built software that juggles invasive weeds, weather patterns, logging plans, road removal and a lot of other factors to see how a forest will change over time.

"We see more of a natural sequence of events that could result in a more normal habitat distribution," Michael Hillis of Missoula's Ecosystem Research Group said of his model for the Beaverhead-Deerlodge National Forest. "But the forest will look much different."

The "B-bar-D" forest covers 3.4 million acres of southwest Montana, bigger than Glacier and Yellowstone national parks combined. Hillis said most of its spruce and Douglas fir stands were logged a century ago for the state's mining industry. The resulting lodgepole stands grew up and matured at the same time, producing what Hillis called the "forest demographics of a rest home" at the perfect age for a beetle epidemic.

Many of those dead trees will then fuel forest fires. While the research is mixed whether a beetle-killed stand burns more dangerously than a green canopy, Hillis said the certain result is more fire scars on the landscape. Those scars in turn will eventually hobble later fires with a matrix of burned and unburned patches. Burned areas may return as new lodgepole stands, which regenerate best after a fire. But the unburned zones could see a return of fir, spruce and other tree species that get a chance to grow without the lodgepoles' choking shade....

Looking across forest to mountains and clouds, "In Glacier National Park," Montana., 1933 - 1942. By Ansel Adams, when he was a National Park Service employee

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