Tree of Heaven (Ailanthus altissima)

Description

Ailanthus altissima /eɪˈlænθəs ælˈtɪsɪmə/, commonly known as tree of heaven, ailanthus, or in 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. While the species rarely lives more than 50 years, some specimens exceed 100 years old. Its remarkable suckering ability makes it possible for this tree to clone itself almost indefinitely (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. A. altissima is a medium-sized tree that reaches heights between 17 and 27 metres (56 and 89 ft) with a diameter at breast height of about 1 metre (39 inches). The bark is smooth and light grey, often becoming somewhat rougher with light tan fissures as the tree ages. The twigs are stout, smooth to lightly pubescent, and reddish or chestnut in colour. They have lenticels as well as heart-shaped leaf scars (i.e. a scar left on the twig after a leaf falls) with many bundle scars (i.e. small marks where the veins of the leaf once connected to the tree) around the edges. The buds are finely pubescent, dome shaped, and partially hidden behind the petiole, though they are completely visible in the dormant season at the sinuses of the leaf scars.The branches are light to dark gray in colour, smooth, lustrous, and containing raised lenticels that become fissures with age. The ends of the branches become pendulous. All parts of the plant have a distinguishing strong odour that is often likened to peanuts, cashews, or rotting cashews.