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Southern Research StationSouthern Research Station
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Oriental bittersweet (Celastrus orbiculatus).
Photo: Z. Hoyle
Date:   July 7 , 2004
Science Contact:  
News Release Contact: Zoë Hoyle

Summer in the South: Kudzu and Oriental Bittersweet

Midsummer finds many places in the southeastern United States engulfed in kudzu and other nonnative invasive plants. Forest Service researchers bring a variety of approaches to this problem.

Forest Fragmentation – SRS researcher Kurt Riitters and collaborators from universities and other federal agencies are using high-resolution land cover maps derived from satellite images to model forest fragmentation in the United States. Recent studies show that, although there are still large uninterrupted areas of forest in the United States, almost 62 percent of U.S. forest land is within 150 meters (492 feet) of the forest edge. Another study found that half of U.S. land area is within 382 meters (1253 feet) of a road. Fragmentation of forests alters or removes habitat, disrupts the movement of wildlife - and promotes the introduction of nonnative invasive plant species. Read the original news release.

CONTACT: Kurt Riitters, Forest Health Monitoring. (919-549-4015) or .


 Nonnative Invasive Plants – Nonnative invasive plants infest millions of acres of public and private forest land in the southeastern United States, and are spreading steadily from disturbed areas into forests. In 2003, SRS researcher, James Miller published a new guide for identifying and controlling the 33 plants that are doing the most damage to Southern forests. Along with detailed identification guides, Nonnative Invasive Plants of Southern Forests provides general control information and specific prescriptions for individual plants.

CONTACT: James Miller, Research Ecologist. (334-826-8700) or . Copies of the guide are available free at (General Technical Report, SRS-62).


Oriental Bittersweet: A Patient Invader - Oriental bittersweet (Celastrus orbiculatus), a woody vine with rounded leaves and small yellowish flowers, was introduced to the United States from Southeast Asia around 1860. The bright orange berries produced in the fall have made oriental bittersweet popular for wreaths and winter flower arrangements, but the pretty vine wreaks havoc on the trees and native plants of the Southern Appalachian forest. Studies by SRS scientists at the Bent Creek Experimental Forest near Asheville, North Carolina provide an understanding of the unique “sit and wait” strategy adopted by the destructive vine. Read more at

CONTACTS: Cathryn Greenberg at 828-667-5261 x 118 or or Henry McNab at 828-667-5261 x 119 or .


Kudzu on trees. Photo: Kerry Britton, USDA Forest Service

Kudzu (Pueraria montana var. lobata) is arguably the most famous exotic plant to invade the southeastern region of the United States. First introduced from Asia in 1876, kudzu vines with their grape soda-scented

blossoms cover millions of acres of disturbed land, forming dense mats over everything, including mature trees. Kudzu is prohibitively expensive to control chemically: SRS scientists are searching in the plant's native range in China for insects that feed onl kudzu. So far, they have identified 110 species of insects as potential biocontrol agents, and are conducting preliminary tests in China on some of the most promising candidates. Read more at

CONTACT: James Hanula, Research Entomologist. (706-559-4253) or

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