(Flagstaff, Ariz.- Jan. 23, 2009) - Global warming is speeding up the mortality of trees, and Northern Arizona University research is providing some of the data to prove it.
Pete Ful, an NAU associate professor in the School of Forestry and a director of the university's Ecological Restoration Institute, is a coauthor of "Widespread Increase of Tree Mortality Rates in the Western United States," an article to be published in the Jan. 23 issue of Science journal.
The study, led by principal authors Phillip J. van Mantgem and Nathan L. Stephenson, scientists with the Western Ecological Research Center for the U.S. Geological Survey in northern California, "offers data to show that there is a problem with tree mortality in the West and that climate is an important element in the problem," Ful explained.
Eleven scientists contributed to the study by providing long-term data sets taken from trees across the Pacific Northwest, California, Idaho, Colorado and Arizona. The article concludes that tree death rates have more than doubled in recent decades in otherwise undisturbed old forestslargely a consequence of regional warming.
"The gist is that we now have these long-term data sets from old trees across much of the western part of the country and one thing those forests have in common is that the trees are dying increasingly fast," Ful said.
To determine when trees died as a result of climate change, scientists documented climate-related incidents that caused trees to die, such as bark beetle attacks or forest fires.
Ful worked with NAU researchers to provide tree measurements from more than 6,000 trees, mostly ponderosa pines, rooted in the Gus Pearson Natural Area established in 1908 and located within the Fort Valley Experimental Forest 12 miles north of Flagstaff. Trees in the experimental forest can reach beyond 500 years old.
The study, conducted in conjunction with the Ecological Resto
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Northern Arizona University