When forests take the hit
This spring, more than 40 percent of the western U.S. is in a drought that the U.S. Department of Agriculture deems “severe” or “exceptional.” The same was true in 2013. In 2012, drought even spread to the humid East. It’s easy to assume that a three-year drought is an inconsequential blip on the radar for ecosystems that develop over centuries to millennia. But new research just released in Ecological Monographs shows how short-lived but severe climatic events can trigger cascades of ecosystem change that last for centuries. Some of the most compelling evidence of how ecosystems respond to drought and other challenges can be found in the trunks of our oldest trees. Results from an analysis of tree rings spanning more than 300,000 square miles and 400 years of history in the eastern U.S. — led by scientists at the Harvard Forest, Columbia’s Lamont-Doherty Earth Observatory, and elsewhere — point to ways in which seemingly stable forests...