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SAN JUAN MOUNTAINS — This traditionally is the peak weekend in large portions of the Rocky Mountains for the changing of aspen leaves. But whether whole mountainsides will still be glowing during autumns in coming decades is less certain.
Aspen forests have been dying on massive scales from Arizona to Alberta, including tens of thousands of acres in the San Juan Mountains in southern Colorado.
Scientists believe that the aging aspen trees have been tipped into decline by a drought that has lasted, with varying intensities, since the 1990s.
Of greatest interest is the condition of the root systems. Normally, aspen stands will soon regenerate, as the roots can remain alive for even thousands of years. But there is some evidence that the roots are also dying.
Silviculturalists, as forestry experts are called, had for decades predicted a die-off.
But Wayne Shepperd, an aspen expert now retired from the U.S. Forest Service, last year told Telluride Magazine that he was caught off guard. He expected the sun-loving aspen trees to be replaced gradually by conifers.
He conceded that the drought made the aging aspen trees more susceptible to disease but he was leery of blaming the drought and mortality to a changing climate.
Aspen springs to life after forest disturbances, such as fire. The last major round of fires was in the 1880s. Aspen trees normally live 100 to 150 years. Logging aspen forests or setting fires will also cause them to regenerate.
But both tools have their limits. The demand for aspen wood is weak, and only 400 to 500 acres per year get harvested in the San Juan Mountains, explains the Durango Herald. Prescribed burns are difficult in the rugged topography that characterizes the region.
Even when trees are being cut, however, they are not regenerating. Jim Worrall, a forest pathologist with the U.S. Forest Service, told The Telluride Watch that what may be happening is that the root systems are getting so drained they cannot respond.
“If those roots die, and we don’t see any sprouts, we aren’t going to see aspen there,” said Shepperd. “It will be a meadow, a conifer forest or something else.”
Aspen forests have been dying on massive scales from Arizona to Alberta, including tens of thousands of acres in the San Juan Mountains in southern Colorado.
Scientists believe that the aging aspen trees have been tipped into decline by a drought that has lasted, with varying intensities, since the 1990s.
Of greatest interest is the condition of the root systems. Normally, aspen stands will soon regenerate, as the roots can remain alive for even thousands of years. But there is some evidence that the roots are also dying.
Silviculturalists, as forestry experts are called, had for decades predicted a die-off.
But Wayne Shepperd, an aspen expert now retired from the U.S. Forest Service, last year told Telluride Magazine that he was caught off guard. He expected the sun-loving aspen trees to be replaced gradually by conifers.
He conceded that the drought made the aging aspen trees more susceptible to disease but he was leery of blaming the drought and mortality to a changing climate.
Aspen springs to life after forest disturbances, such as fire. The last major round of fires was in the 1880s. Aspen trees normally live 100 to 150 years. Logging aspen forests or setting fires will also cause them to regenerate.
But both tools have their limits. The demand for aspen wood is weak, and only 400 to 500 acres per year get harvested in the San Juan Mountains, explains the Durango Herald. Prescribed burns are difficult in the rugged topography that characterizes the region.
Even when trees are being cut, however, they are not regenerating. Jim Worrall, a forest pathologist with the U.S. Forest Service, told The Telluride Watch that what may be happening is that the root systems are getting so drained they cannot respond.
“If those roots die, and we don’t see any sprouts, we aren’t going to see aspen there,” said Shepperd. “It will be a meadow, a conifer forest or something else.”
Police struggle with graffiti, fights
SOUTH LAKE TAHOE, Calif. — Police report proliferating graffiti and fighting among several dozen young men, high-school aged or younger, in an area of South Lake Tahoe populated by Latinos. Police tell the Tahoe Daily Tribune that the case is difficult because there are neither victims nor witnesses in what they suspect is gang-related violence.
