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Tree-of-heaven
NATIVE RANGE: Central China
Its large compound leaves, 1-4 feet in length, are composed of 11-25 smaller leaflets and alternate along the stems. Each leaflet has one to several glandular teeth near the base.
In late spring, clusters of small, yellow-green flowers appear near the tips of branches. Seeds are produced on female trees in late summer to early fall, in flat, twisted, papery structures called samaras, which may remain on the trees for long periods of time. The wood of ailanthus is soft, weak, coarse-grained, and creamy white to light brown in color. All parts of the tree, especially the flowers, have a strong, offensive odor, which some have likened to peanuts or cashews.
NOTE: Correct identification of ailanthus is essential. Several native shrubs, like sumacs, and trees, like ash, black walnut and pecan, can be confused with ailanthus. Staghorn sumac (Rhus typhina), native to the eastern U.S., is distinguished from ailanthus by its fuzzy, reddish-brown branches and leaf stems, erect, red, fuzzy fruits, and leaflets with toothed margins. ECOLOGICAL THREAT: Tree-of-heaven is a prolific seed producer, grows rapidly, and can overrun native vegetation. Once established, it can quickly take over a site and form an impenetrable thicket. Ailanthus trees also produces toxins that prevent the establishment of other plant species. The root system is aggressive enough to cause damage to sewers and foundations. DISTRIBUTION IN THE UNITED STATES: Tree-of-heaven is widely distributed across the United States, occurring in forty-two states, from Maine to Florida and west to California. Click here to see a distribution map. HABITAT IN THE UNITED STATES: Tree-of-heaven is a common tree in disturbed urban areas, where it sprouts up just about anywhere, including alleys, sidewalks, parking lots, and streets. The book "A Tree Grows in Brooklyn", by Betty Smith based on the ailanthus tree. Away from cities, it is commonly seen in fields, and along roadsides, fencerows, woodland edges and forest openings. Nationally, ailanthus has become an agricultural pest and may occur as seedlings that pop up by the hundreds in recently planted fields, or as persistent thickets in rocky, untillable areas. BACKGROUND: Tree-of-heaven was first introduced to America by a gardener in Philadelphia, PA, in 1784, and by 1840 was commonly available from nurseries. The species was also brought into California mainly by the Chinese who came to California during the goldrush in the mid-1800s. Today it is frequently found in abandoned mining sites there. The history of ailanthus in China is as old as the written language of the country. BIOLOGY & SPREAD: Tree-of-heaven reproduces both sexually (seeds) and asexually (vegetative sprouts). Flowering occurs late in the spring (June in the middle Atlantic region of eastern U.S.). The species is dioecious, with male and female flowering on separate trees. Fruits are papery, somewhat twisted, winged structures called samaras that are tan to pink-colored. Samaras occur in large clusters from September to October of the same year, and may persist on the tree through the following winter. One study reports that an individual tree can produce as many as 325,000 seeds per year. Established trees also produce numerous suckers from the roots and resprout vigorously from cut stumps and root fragments. SUGGESTED ALTERNATIVE PLANTS: Many lovely native trees and shrubs make excellent substitutes for Ailanthus and are readily available. Some examples for the eastern United States include deciduous shrubs such as staghorn sumac (Rhus typhina), smooth sumac (Rhus glabra), box elder (Acer nigrum), fringetree (Chionanthus virginicus), ash (Fraxinus spp.), and black walnut (Juglans nigra). Because U.S. native plants can become invasive outside their natural, historical ranges, be sure to use plant species native to the ecological region you live in. Check with your local native plant society for recommendations of species and sources of native plants. AUTHORS: Jil M. Swearingen, National Park Service, Washington, DC Phil Pannill, Maryland Department of Natural Resources, Forest Service, Hagerstown, MD. For more information
on garlic mustard, please contact: REFERENCES: Bory, G. and D. Clair-Maczulajtys. 1980.
Production, dissemination and polymorphism of seeds in Ailanthus altissima.
Revue Generale de Botanique 88(1049/1051): 297-311 [in French].
Plant Conservation Alliance, Alien Plant Working Group. |
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