UNIVERSITY PARK, Pa. -- Invasive plants are causing a severe problem in Pennsylvania by interfering with the regeneration of native trees, according to an expert in Penn State's College of Agricultural Sciences, who has written three new fact sheets to help private forest owners and other land managers understand the threat and take action.

"Weeds don't only cause problems in farms and gardens; they are major nuisances in our forests as well," says David Jackson, forest resources extension educator. "Weeds that cause economic or environmental harm are also known as invasive plants." "Most invasive plants in Pennsylvania were either intentionally or unintentionally introduced to our region from other parts of the world.

"Without the animals, plants and natural processes that keep foreign plants in balance in their homelands," he adds, "they can quickly invade our forests and natural areas, displacing our native plants." Jackson profiled three especially troublesome species for the Penn State Forest Resources Extension's Invasive Weeds publication series:

--Autumn olive, a large shrub introduced from Asia in the 1830s, was planted widely in the 1960s to provide wildlife food and cover; --Japanese barberry, introduced from Japan around 1875, was planted as an ornamental shrub for its scarlet fruit and orange-red autumn foliage;

--Tree-of-heaven, a fast-growing tree with compound, sumac-like leaves, has a strong, distinct smell. A gardener in Philadelphia brought tree-of-heaven to the United States in 1874.

All of these plants are spread easily with the help of birds or wind. Other species profiled in the Invasive Weeds series include: Japanese and giant knotweed, bush honeysuckles, multiflora rose, Oriental bittersweet and mile-a-minute weed.

To request a free copy of any of the titles in the Invasive Weeds series, contact the Pennsylvania Forest Stewardship Program by calling (800) 235-WISE (toll free), or by sending e-mail to http://rnrext.cas.psu.edu/. Writer: Amy Ridenhour Editor: Jeff Mulhollem 814-863-2719 #185 jjm29@psu.edu

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EDITORS: Contact David Jackson at 814-355-4897 or e-mail drj11@psu.edu.

Contact:

Writer: Amy Ridenhour

Editor: Gary Abdullah gxa2@psu.edu Jeff Mulhollem jjm29@psu.edu 814-863-2719 814-863-9877 fax #185