Trees in trouble

Federal researchers studying the alarmingly fast pace of tree deaths suspect global warming is responsible for the devastating trend.

Mortality rates for trees in the West’s old-growth forests have more than doubled, according to the U.S. Geological Survey. Published last month in Science, the study looked at a wide variety of forests at all elevations.

Scientists say many species of trees, of all sizes, were included in the survey. Researchers ruled out air pollution, fire suppression, and normal forest dynamics as the source of the increasing rates. In the West, the average temperature has increased by 1 degree over the past couple of decades, reducing the winter snowpack and lengthening the summer drought.

USGS scientist Phil van Mantgem noted that, regardless of the cause, the outcome of the deaths could spell significant changes to Western forests. Chief among the concerns is the welfare of the region’s wildlife.