Tag Archives: elevation

New CU-Boulder led research effort dates oldest petroglyphs known in North America

A new high-tech analysis led by a University of Colorado Boulder researcher shows the oldest known petroglyphs in North America, which are cut into several boulders in western Nevada, date to at least 10,500 years ago and perhaps even as far back as 14,800 years ago.

The petroglyphs located at the Winnemucca Lake petroglyph site 35 miles northeast of Reno consist of large, deeply carved grooves and dots forming complex designs on several large limestone boulders that have been known about for decades, said CU-Boulder researcher Larry Benson, who led the new effort.  Although there are no people, animals or handprint symbols depicted, the petroglyph designs include a series of vertical, chain-like symbols and a number of smaller pits deeply incised with a type of hard rock scraper. (more…)

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Bright Outlook for Fall Foliage

North Carolina’s fall foliage should put on a vivid show as it washes over the state this month. With color already beginning to pop in the western mountains, the foliage forecast is bright, says Dr. Robert Bardon, forestry and environmental resources professor at North Carolina State University.

“The biggest thing to worry about is wet rainy weather that can dampen colors,” Bardon says. “If there’s enough wind and rain, trees can begin dropping leaves.” (more…)

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Droughts are Pushing Trees to the Limit

Droughts in the Southwest made more severe by warming temperatures are putting plants in stressful growing conditions, a new study has found, identifying an increasingly water-thirsty atmosphere as a key force that sucks moisture from plants, leading to potentially higher stress – especially in mid and low elevations.

As temperatures rise and droughts become more severe in the Southwest, trees are increasingly up against extremely stressful growing conditions, especially in low to middle elevations, University of Arizona researchers report in a study soon to be published in the Journal of Geophysical Research Biogeosciences.

Lead author Jeremy Weiss, a senior research specialist in the UA department of geosciences, said: “We know the climate in the Southwest is getting warmer, but we wanted to investigate how the higher temperatures might interact with the highly variable precipitation typical of the region.” (more…)

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