Pine Beetles Changing Rocky Mountain Air Quality, Weather When pine bark beetles kill trees, scientists believe they may also alter local weather patterns and air quality. For the next four years researchers will study forests from southern Wyoming to northern New Mexico to determine the precise relationship between the beetles, the trees they kill and the atmosphere. A new international field project, led by scientists at the National Center for Atmospheric Research in Boulder, is exploring how trees killed by the beetles influence rainfall, temperatures, smog and other aspects of the atmosphere. "Forests help control the atmosphere, and there's a big difference between the impacts of a living forest and a dead forest," says NCAR scientist Alex Guenther, a principal investigator on the project. "With a dead forest, we may get different rainfall patterns, for example." Preliminary computer modeling suggests that beetle kill can lead to temporary temperature increases of between two and four degrees Fahrenheit. This is partly because of a lack of foliage to reflect the Sun's heat back into space. Beetle kill stimulates trees to release more particles and chemicals into the atmosphere as they try to fight off the insects, Guenther says. This worsens air quality, at least initially, by increasing levels of ground-level ozone and particulate matter....