Description

The Tree of Heaven is a rapidly growing dioecioushaving the male and female reproductive organs on separate plants (of the same species) rather than different parts of the same plant tree that can reach over 60 feet in height. The leaves are 1-3 feet long. Each leaf is comprised of 11-25 ovate- lanceolateshaped like the head of a lance; of a narrow oval shape tapering to a point at each end leaflets which are each 3-5 inches long. They are truncate at the base and acute or acuminate at the apex. There are usually one or more coarse teeth at the base of the leaflet, and each of these teeth has a large gland beneath it. The bark of this tree is extremely smooth and pale gray in color. The inflorescence is pyramidal in shape and is 4-8 inches long with greenish to greenish-yellow flowers (0.2 inches) that appear in late spring. The staminate flowers and broken twigs have an unpleasant scent. The fruits are twisted samaras that appear from September to October on the female trees. They are yellow-green to orange-red and changing to brown in the winter, and are 2 inches long.

Habitat

The Tree of Heaven can be found in a variety of habitats, such as disturbed urban areas, alleys, along sidewalks, along streets, fields, fencerows, woodland edges, forest gaps, and agricultural fields.

History and Introduction

Ailanthus altissima was brought to England from China in 1751. It was then introduced into the United States in Philadelphia, Pennsylvania in 1784 by a gardener named William Hamilton. By 1840 it was being sold by nurseries for its foliage. It has been used extensively for plantings in cities because of its rapid growth and resistance to air pollution. It is from these city plantings that this plant has escaped and extended its range not only into New England, but into the majority of the country.

Threats

Because of its rapid growth, this tree can easily displace some native vegetation. It also produces toxins that can prevent the establishment of other plant species. The root system of the plant can cause damage to sewers and foundations. When cut down this tree can produce suckers and stump sprouts. A single tree can produce 325,000 wind dispersed seeds a year. The sap of this species may cause myocarditisinflammation of the heart muscle if it is internalized.

Dispersal Methods

The primary method of dispersal for Tree of Heaven is by wind. However, the fruits are also light enough to float and could be moved by water.

Control

Mechanical

Young seedlings may be pulled or dug up, preferably when soil is moist. Care must be taken to remove the entire plant including all roots and fragments. Cutting large seed producing female trees would at least temporarily reduce spread by this method.

Chemical

It can be effectively controlled using any of several readily available general use herbicides such as triclopyrherbicide used to control both broadleaf and woody plants or imazapyra non-selective herbicide used for the control of a broad range of weeds including terrestrialgrasses and broadleaved herbs, woody species, and riparian and emergent aquatic species. Follow label and state requirements. The herbicides may be applied as a foliar (to the leaves), basal bark, cut stump, or hack and squirt treatment. Basal bark application is one of the easiest methods and does not require any cutting. It works best during late winter/early spring and in summer. The cut stump method is useful in areas where the trees need to be removed from the site and will be cut as part of the process. The hack-and-squirt or injection method is very effective and minimizes sprouting and suckering when applied during the summer. 

Biocontrol

A potential biological control for ailanthus may lie in several fungal pathogens, (Verticillium dahliae and Fusarium oxysporum) that have been isolated from dead and dying ailanthus trees in New York and in southern and western Virginia.