Aspen Dieoff Underway In Western US - Cause Remains Unknown - NYT

[hatrack]

DENVER, Sept. 25 — The aspen, an emblematic tree of the West and the most widely distributed tree in North America, is rapidly and mysteriously dying. Its rapid decline is bewildering scientists and forest ecologists, who say they cannot pinpoint a cause. “What’s causing the aspen to die?” asked Wayne Shepperd, a veteran researcher at the Rocky Mountain Research Center of the United States Forest Service. “We don’t know. Maybe this has been there all along, and we haven’t noticed it before, or maybe it’s something new.”

There is no shortage of suspects. Forest experts, who met this month at a conference in Utah to discuss the problem and look for solutions, say it may be insects, drought or climatic stress in general or overgrazing by animals like elk and cattle. Or it may be none or all of the above. The aspen dieback is particularly baffling in that it seems to be occurring just in some Western states and is not affecting any neighboring trees, many of which already suffer from a plague of mountain pine beetles that has been devastating the West.

Since word of the aspen dieback began spreading last fall, Dr. Shepperd’s office began receiving reports of similar losses throughout the West — not just Colorado, where the problem is most predominant, but also in Utah, Idaho, Nevada, Montana, Arizona and southern Wyoming. But because there has been no concerted investigation, it is not clear how many aspen have died, much less why. “Quite honestly we just don’t have any answers,” Dr. Shepperd said.

The die-off is particularly worrisome because of the special nature of the aspen. The tree reproduces through vegetative regeneration. Genetically identical suckers sprout from the root of one tree and become clones. If the root of an aspen dies, it is unlikely to reproduce.

EDIT

http://www.nytimes.com/2006/09/26/science/earth/26aspen.html?_r=1&oref=slogin

[soothsayer]

1. I blame Scooter libby, and the reporter chick who sat in jail.