June 24, 2013 — An exotic tree species that changed from prized possession to forest management nightmare serves as a lesson in the unpredictability of non-native species mixing with human interactions, according to researchers.
“There are other invasive tree species in Pennsylvania, but the ailanthus, by far, has been here longer and does more damage than any other invasive tree,” said Matthew Kasson, who received his doctorate in plant pathology and environmental microbiology from Penn State. “It’s the number one cause of native regeneration failure in clearcuts in Pennsylvania.”
Kasson, who is a post-doctoral researcher in plant pathology, physiology and weed science at Virginia Tech, said that William Hamilton, a pioneer botanist who corresponded with William Bartram and Thomas Jefferson, imported the first ailanthus altissima — Tree-of-Heaven — a tree native to China, from England sometime between 1784 and 1785 and cultivated the tree on his estate, the Woodlands, in Philadelphia. The deciduous tree, which grows rapidly, often to a height of 50 feet, has become one of the biggest forest management problems, especially since the 1980s, according to the researchers.
Kasson and colleagues report in a recent issue of the Northeastern Naturalist that ailanthus can invade quickly in areas where large, continuous stands of trees are cut down — clearcuts — and displace slower-growing native plants. [ … continue ]