More than 100 researchers gather in Utah to try and discover why aspen trees are dying

(AP) Aspen trees have been dying off, leaving dwindling numbers of the white-barked fixture of the Western mountain landscape. Nobody is quite sure why.

More than 100 researchers gathered at Utah State University this week for a two-day conference called "Restoring the West: Aspen Restoration."

The trees reproduce with a wide root system, that spawns other trees nearby. Even if the parent tree dies, the surviving root system can support new trees.

U.S. Forest Service researcher Wayne Shepperd said in some Colorado stands, the entire root networks have perished.

"If we're losing roots," Shepperd said, "that's going to change the amount of aspens on the landscape."

The researchers are trying to figure out why aspens, native to the higher elevations of the region, have been dying.

In addition to ecological diversity and the aesthetics of an aspen grove on a quiet mountainside, the trees also affect watersheds. With the decrease in aspens, conifers are encroaching on aspen territory.

"There may be significant loss of water resources that could be coming out of these watersheds," said Ron Ryel, a Utah State University researcher on wildland resources.

Researchers have found differences between the sizes of snowpacks near aspens and conifers, which can affect how much water is available for use in the summer.

Utah has lost an estimated 50 percent of its aspen population since North America was colonized, Ryel said. And the decline runs along the Rocky Mountains from Arizona to Alberta, Canada.

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Information from: The Salt Lake Tribune, http://www.sltrib.com