New Evidence of Western Forest Decline

In Colorado’s San Juan National Forest, between 7,000 and 10,000 feet, quaking aspen grow in glorious, shimmering groves. In mid-2004, Forest Service rangers noticed the aspen groves sickening. Trees crowns browned in patchy clusters. Their lime-green, spear-shaped leaves dropped. Aerial surveys observed a rapidly widening area of forest illness and death in the years that followed. Sudden aspen decline, or SAD, as scientists have termed the crown deterioration, spread from southwest Colorado throughout the entire western half of the state. At its peak, in 2008, 300 new square miles of forest succumbed in one year. SAD also took hold in Utah, Minnesota and Arizona, and in the Canadian provinces of Ontario, Alberta and Saskatchewan. The episode of die-offs that had begun in 2004 has since abated. But the sheer scale of the die-off, and concern that it could recur, has researchers monitoring the recovering forest.

Source: Pulitzer Centre, August 17, 2017
http://pulitzercenter.org/reporting/researcher-finds-new-evidence-weste…