Ailanthus altissima , commonly known as tree of heaven, ailanthus, or in Standard Chinese as chouchun (Chinese: 臭椿; pinyin: chòuchūn; literally: "foul smelling tree"), is a deciduous tree in the Simaroubaceae family. It is native to both northeast and central China, as well as Taiwan. Unlike other members of the genus Ailanthus, it is found in temperate climates rather than the tropics. The tree grows rapidly and is capable of reaching heights of 15 metres (49 ft) in 25 years. However, the species is also short lived and rarely lives more than 50 years, though its remarkable suckering ability makes it possible for this tree to clone itself indefinitely and live considerably longer (since they are linked to the mother tree and thus partly fed by it, the suckers are less vulnerable than the seedlings and can grow faster).
In China, the tree of heaven has a long and rich history. It was mentioned in the oldest extant Chinese dictionary and listed in countless Chinese medical texts for its purported ability to cure ailments ranging from mental illness to baldness. The roots, leaves and bark are still used today in traditional Chinese medicine, primarily as an astringent. The tree has been grown extensively both in China and abroad as a host plant for the ailanthus silkmoth, a moth involved in silk production. Ailanthus has become a part of western culture as well, with the tree serving as the central metaphor and subject matter of the best-selling American novel A Tree Grows in Brooklyn by Betty Smith.
The tree was first brought from China to Europe in the 1740s and to the United States in 1784. It was one of the first trees brought west during a time when chinoiserie was dominating European arts, and was initially hailed as a beautiful garden specimen. However, enthusiasm soon waned after gardeners became familiar with its suckering habits and its foul smelling odour. Despite this, it was used extensively as a street tree during much of the 19th century. Outside Europe and the United States the plant has been spread to many other areas beyond its native range. In a number of these, it has become an invasive species due to its ability both to colonise disturbed areas quickly and to suppress competition with allelopathic chemicals. It is considered a noxious weed in Australia, the United States, New Zealand and many countries of central, eastern and southern Europe. The tree also resprouts vigorously when cut, making its eradication difficult and time-consuming. In many urban areas, it has acquired the derisive nicknames of "ghetto palm", "stink tree", and "tree of Hell".