Aspen trees across the West have been fading away over the past decade, a phenomenon scientists have termed "sudden aspen decline." After several years of investigation scientists believe drought is the primary factor in SAD, Eryn Gable of Greenwire reports for The New York Times, though a secondary pathogen or insect eventually kills the tree. Unlike other declines in aspen populations, affected trees don't show normal levels of rebound.
In an attempt to revitalize aspen populations, the Forest Service recently approved plans for scheduled burns and clear-cuts on federal land. Aspen stands in southwestern Colorado, northern Arizona, southern Utah, southern Wyoming and southeastern Idaho have been hit particularly hard by SAD, Gable reports. An aerial survey in Colorado showed 17 percent of the state's aspens had been affected.
SAD has led foresters to reconfigure their annual timber programs. "We've changed our focus from green trees to dead and dying trees,"Mark Krabath, a supervisory forester for the Dolores Public Lands Office in Colorado, told Gable. Some foresters fear that any aspen stands are already too far gone to help. "The part we don't know is, what's the threshold? How bad can SAD be and can we still stimulate adequate regeneration through treatment?" forest pathologist Jim Worrall told Gable. (Read more)
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