Tree Mortality and Drought to Come in Southwestern US

A warmer and drier Southwestern United states will cause extensive tree mortality as well as substantial changes in forest and species distribution, researchers say.

As greenhouse gases accumulate in the atmosphere and rising temperatures in the Southwest region of the US have been the trend since the late 1800s, research indicates that forests in the area will have high stress levels of drought and trees will die at faster and larger rates in the summer months.

A team of scientists from Los Alamos National Library, the U.S Geological Survey, University of Arizona, and several other partner organizations published an article in Nature Climate Change this week stating that “temperature is a potent driver of regional forest drought stress and tree mortality”.

The study also indicated that the severe wildfires, bark-beetle outbreaks, and a doubling of the proportion of dead trees in the southwest shows that forests are already reacting to the changing climates of the 21st century.

“This paper is a breakthrough,” said staff scientist at Los Alamos National Library Nate McDowell. “The ultimate conclusion of our study is that in a warmer world, we won’t be able to have forests in many places where they exist today. Continued warming will cause forest distributions to change substantially in the southwestern United States.”