Experiments Suggest Grassland May Replace Forest in U.S. Southwest

http://www.scientificamerican.com/article.cfm?id=experiments-suggest-grassland-may-replace-forest-in-us-southwest


EXPERIMENTAL FUTURE: Chambers simulating hotter and drier weather test pinyon and juniper trees, suggesting that southwestern forests may transition to grasslands.
Image: Josh Smith and Los Alamos National Laboratory

In the steel and Plexiglas chambers that make up Nathan McDowell's research station near the Bandelier National Monument in New Mexico, the future of regional forests is playing out in miniature. McDowell is baking trees.

Inside the chambers, temperatures climb 9 degrees Fahrenheit above the desert's already blistering averages. Meanwhile, precipitation, never abundant in this corner of the country, is cut by half.

This is the kind of climate that the United Nations' Intergovernmental Panel on Climate Change (IPCC) projects for the Southwest within the next half-century, as global warming drives heat and aridity in an already hot, dry region.