Environment Planet Earth 10 Disgusting, Diseased Trees We Don't Want to Hug (Slideshow) By Jeff Kart Updated October 11, 2018 Migrated Image Share Twitter Pinterest Email Environment Weather Outdoors Conservation Trees. They provide shade. They turn carbon dioxide into oxygen. They're the perfect shape for hugging. Unless they're riddled with disease. There are dozens of diseases that sicken or kill trees in the United States. There also are bugs that make trees more prone to disease, like the Emerald Ash Borer, first found in Detroit in 2002. The bug, native to Asia, likely arrived here in shipping containers. It starts out as larvae that feed on the inner bark of ash trees, and has killed tens of millions of ash in Michigan, other states, and Canada since first being discovered, according to emeraldashborer.info, a clearinghouse site. The borer is just one of a number of insects and afflictions that make trees less huggable. Climate change is likely to bring news diseases to new areas, according to U.S. Forest Service officials. Get ready to meet some of your new neighbors.