Heat Kills

A triple combination of heat, drought and lowered resistance against bark beetles are working together to cause a massive die off of pinyon pine trees throughout the Southwest.

The image on the left was taken in October of 2002 and shows already weakened trees with reddish-brown foliage in a 60,000 woodland region in northern New Mexico. The image on the right shows the same region in May of 2004. By then, many of the pinions were either dead or dying, their gray trunks exposed because their needles fell off.

The New Mexico woodlands were the focus of an extensive joint-study by researchers from Northern Arizona University and the Los Alamos National Laboratory. The researchers believe global warming may be responsible for the higher temperatures and droughts.

Their findings were recently published in an online version of the journal for the Proceedings of the National Academy of Sciences.

--Ker Than

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Credit:  D. Allen, U.S. Geological Survey