• Spread by trade and climate, bugs butcher America’s forests

    In this Oct. 5, 2016 photo, distressed and dying hemlock trees are seen at Harvard University's research forest in Petersham, Mass. Forests from New England to the West Coast are jeopardized by invasive pests that defoliate and kill trees. Scientists said the pests are driving some tree species toward extinction and causing billions of dollars a year in damage. (AP Photo/Elise Amendola)

    PETERSHAM, Mass. (AP) — In a towering forest of centuries-old eastern hemlocks, it’s easy to miss one of the tree’s nemeses. No larger than a speck of pepper, the Hemlock woolly adelgid spends its life on the underside of needles sucking sap, eventually killing the tree.