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Welcome to the Eastern Forest Environmental Threat Assessment Center!
Message from the Director...
Dr. Danny C. Lee
EFETAC is addressing a variety of complex issues that demand cross-disciplinary integration, collaboration, and creativity. Our work complements ongoing efforts within and outside the Forest Service and builds on a wealth of existing information. Our scientists collaborate with an extensive national and international research community and focus on research that is relevant to rural and urban forest threat issues. More...
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Featured Forest Threat
Tree of Heaven (Ailanthus altissima)
Tree of heaven is native to eastern and central China. It was valued for its use as a horticultural specimen, a street tree, and a shade tree, after its introduction into the U.S. in 1784.
What is tree of heaven? Tree of heaven is a rapidly growing, deciduous tree in the mostly tropical quassia family. Mature trees can reach 80 ft. or more in height. It has smooth stems with pale gray bark, light chestnut brown twigs, and large compound leaves. Small yellow-green flowers with 5-6 petals are borne in dense clusters near the ends of the upper stems. The tree’s pink to tan fruit is winged with a single seed in the middle. All parts of the tree, especially the flowers, have a strong, offensive odor similar to peanuts or cashews.
How does it spread? Tree of heaven reproduces from prolific wind- and water-dispersed seeds and from numerous root suckers that allow it to re-sprout vigorously from cut stumps and root fragments. Tree of heaven occupies disturbed soils, fields, roadsides, fencerows, woodland edges, forest openings, and rocky areas; it is not found in wetlands or shaded areas. It thrives in poor soils and tolerates pollution.
Why is tree of heaven a concern? Tree of heaven grows rapidly and once established, forms dense stands and impenetrable thickets that can overrun native vegetation. It also produces toxins that prevent the establishment of other plant species.
Visit the Forest Threat Summary Viewer for more information about this and other forest threats.
Source: U.S. Forest Service Northeastern Area Forest Health Protection "Weed of the Week"
Photo by James H. Miller, U.S. Forest Service, Bugwood.org
