Invasive species threaten to raze entire forests while scientists rush to find solutions to save the trees

Trees in the United States are sick and dying at exponentially high rates, reports Catrin Einhorn for The New York Times. While scientists rush to keep up with preventative measures to save entire species, they worry about what has already been lost, and what might continue disappearing if they're not fast enough to save the trees that remain. 

"Epidemics are escalating, across numerous species, as more and more pests and pathogens invade forests," Einhorn writes. "Their entryway is global trade — in live plants, and in the countless products that are shipped in wooden pallets, crates and other packaging. As trade has boomed, so have the opportunities for tiny stowaways to wreak havoc."

Those tiny stowaways include the emerald ash borer, which has feasted on ash trees for decades, and the aphid-like wooly adelgid that attacks the Eastern hemlock, chewing on the tender flesh of the tree just under the bark, cutting off the trees' food and water supply in the process. 

"The attackers have killed billions of trees already, with countless more under threat. In some severe cases, forests are transforming into bleak spaces of brambles and vines," Einhorn reports. The impacts aren't contained in the forest, either. "Trees filter water, stabilize the land and clean the air. They absorb and store planet-warming carbon dioxide, fighting climate change. They create the three-dimensional habitat that countless species use for shelter and shade." 

Scientists are racing to find solutions, but they're finding it hard to keep up with the speed at which these tiny invaders are devouring forests. The northeastern U.S. has become the epicenter of the converging epidemics, where six of the most prominent ash tree species have been listed as endangered or critically endangered since 2002.