WASHINGTON, Oct. 2 (UPI) -- U.S. university and federal researchers expressed concern about the long-term health of forests in the southwestern United States given recent climate trends.
Scientists from the Los Alamos National Laboratory, the U.S. Geological Survey, the University of Arizona and partner organizations said that if warmer temperatures and drought continue for the southwestern states, forest ecosystems could change dramatically.
Researchers, in a study published in the journal Nature Climate Change, compared historical tree ring and climate records to future climate change predictions. They said higher temperatures in the region could put a strain on forests. Warmer summers, they said, limit growth following wetter winters.
Scientists said the last so-called megadrought occurred in the 1500s.
A. Park Williams, the lead researcher in the study, said tree ring records from that period showed exceptionally slow growth rates.
"If forest drought stress exceeds late 1500 levels, we expect that a lot of trees are going to be dying," he said in a statement.
The National Oceanic and Atmospheric Administration concluded recent droughts in the United States were more likely because of warming trends.
July was the warmest month on record for the Lower 48 states since record-keeping began in the late 1800s.
