By Science News
![Recent monitoring (from a gondola in Washington state, shown) reveals that rates of tree death are up. Credit: Univ. of Washington](https://i0.wp.com/www.sciencenews.org/wp-content/uploads/2009/12/environment.jpeg?resize=300%2C186&ssl=1)
Routine tree deaths doubled
Small background rates of everyday tree death have doubled in old-growth, western forests since 1955, possibly because of climate change, researchers report (SN: 2/14/09, p. 8). In 76 plots with no wildfires or massive pest outbreaks in the western United States and Canada, annual tree mortality crept up to 1 or 2 percent by 2007, says Phillip J. van Mantgem of the U.S. Geological Survey’s Western Ecological Research Center field station in Arcata, Calif. Deaths accelerated in trees of various ages, altitudes and shade preferences, even in national parks — where the air is relatively unpolluted. To explain such widespread effects, van Mantgem and colleagues point to the many consequences of the West’s recent temperature increase. Because more trees now die than sprout each year in the study areas, the forests may be faltering in their role as climate-friendly storehouses of carbon.