Forest Die-Off Linked to Global Warming

Researchers believe the massive die-offs of New Mexico’s state tree, the pinyon, during the drought of 2002 and 2003 could be a harbinger of life in a warming world.

High-elevation pinyon forests that had survived previous droughts endured as much as 90% mortality during that drought, Arizona researchers reported in the Proceedings of the National Academy of Sciences. Drought weakened the trees enough for bark beetles to kill them, and warmer temperatures -- only 1 to 2 degrees Fahrenheit higher than the long-term average -- appear to have contributed, the scientists found.