by Michael Kodas, via On Earth
In a little over a decade, the largest mountain pine beetle outbreak on record (by a factor of 10) has killed more than 70,000 square miles of Rocky Mountain forests — an area the size of Washington State. From above, the infested pine trees seem color-coded: green is healthy, red is dead, and after three or four years, the dead red needles fall off, leaving behind a graveyard of bare gray bark — or, if you’re worried about wildfires, what amounts to a field of 100-foot-tall matchsticks.
Colorado, already facing the most destructive wildfire season in state history, has 3.3 million acres of beetle-killed forests to worry about. No one doubts that dead and dying trees are a potential problem, but fears that the beetle infestation will fuel larger firestorms might be premature (at least in the short term). Across the West, some 40 scientific studies have failed to produce a clear picture of how millions of beetle-killed trees will burn.
One recent paper by researches at the U.S. Forest Service and University of Idaho predicts that during the “red phase” — when trees are dead but still have rust-colored needles — severe crown ...