Ailanthus

The best known species, A. altissima, English name Tree of heaven, is a quick-growing deciduous tree to 25-35m tall, with spreading branches and large (40-80cm) pinnate leaves with 15-35 long pointed leaflets, terminal leaflet normally present, and the basal pairs of leaflets often lobed at their bases. The small greenish flowers are borne on branched panicles; and the male ones are characterized by having a disgusting odour. The fruits are free in clusters, and each is drawn out into a long wing with the seed in the middle. The wood is fine grained and satiny. The tree, which is a native of northern China, was introduced into England in 1751 and is a favourite in parks and gardens. It has also been introduced into North America.

Where the climate is sufficiently similar to that of its homeland, as in much of the east and south of both the USA and Europe, it has proved to be a serious problem invasive species, causing major problems both in urban areas (where the roots of seaplings that germinate close to buildings cause damage to foundations), and in rural areas (where it displaces native species from the environment). A consequent popular nick-name for the species is Tree from hell.

Other species of Ailanthus are: A. triphysa, an Australian tree; A. vilmoriniana and A. giraldii in southern & western China, A. malabarica in southeast Asia, and A. excelsa, common in India.

A silk spinning moth, the Ailanthus moth (Samia cynthia), lives on its leaves, and yields a silk more durable and cheaper than mulberry silk, but inferior to it in fineness and gloss. This moth is common near many towns in the eastern United States; it is about 5 in. across, with angulated wings, and in colour olive brown, with white markings.

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