Earth Equity News

Trees Dying at Alarming Rate, Study Warns. By Dawn Walton, Toronto Globe and Mail, January 23, 2009. "The death of old-growth forests in the western United States and Canada is increasing at a stunning rate, a troubling trend linked directly to global warming that could soon transform forests into carbon-dioxide emitters rather than much-needed carbon sinks, a new study warns. Scientists have found that tree mortality has more than doubled in the past few decades regardless of elevation, forest type or tree size as pine, fir, hemlock and other species are dying faster than new trees are growing. 'In the future, forests might store less carbon than they do at present, and it also introduces the possibility that western forests could become net sources of carbon dioxide to the atmosphere, further speeding up the pace of global warming,' said study co-author Dr. Phillip van Mantgem of the U.S. Geological Survey's Western Ecological Research Center in California. When dead trees start to decompose, they release carbon dioxide into the atmosphere. The report, published today in the journal Science, examined 76 undisturbed stands in Oregon, Washington, California, Arizona, Colorado, New Mexico and British Columbia, which were at least 200 years old. Some were more than 1,000 years old. Researchers, who have been counting trees since 1955, found that mortality rates increased in the majority of areas studied. They also found that the death rate doubled in the Pacific Northwest in 17-year period and doubled every 29 years in the U.S. interior. What's worse, the stands surveyed were considered healthy and resilient, which suggests that the trees in mountain-pine-beetle-infested regions such as British Columbia and those hit by higher forest-fire rates are dying at an even more dramatic clip, researchers said."