ailanto G. (Ailanthus el simarubacoj) de arboj, kun grandaj (0,5-1 m longaj), plume kunmetaj folioj k kun flugilhavaj fruktoj (samaroj); 5 sp-oj hejmaj de Azio ĝis Aŭstralio, i.a. A. altissima, naturigita en N Ameriko k C k S Eŭropo, pasintece kultivata por bredado de sp. de silkraŭpo (Samia cynthia). - La Nova Plena Ilustrita Vortaro de Esperanto
The Tree of Heaven is now commonly known as That Darn Weed, because it grows everywhere and is nearly impossible to kill. But I like them! Strangely enough, this tree was imported for use as an ornamental shade tree throughout the eastern United States. People actually paid for it! It is a Chinese species that grows very rapidly, thrives in almost all soils and climates, resists practically all insects and diseases, and tolerates soot and pollution better than any other tree, native or foreign. It gained fame as "the tree that grows in Brooklyn". I've seen them growing through cracks in sidewalks and atop brick walls and even up on flat rooftops!
The genus Ailanthus contains about 10 species, native to Asia and northern Australia. It was introduced into England from China in the mid-18th century as an ornamental, migrating to the United States in 1874. The term Ailanthus is derived from the Moluccan name aylanto meaning tree-of-heaven and referring to the height of the tree; Altissima means "very tall". According to Nature Bulletin No. 563-A of the Forest Preserve District of Cook County, Illinois, Ailanthus is the Latinized form of ailanto, a native word of the East Indies, meaning Tree of Heaven - a tree that overtops other trees. The Encarta World English dictionary spells it ai lanto, and says that it's an Amboinese, or Ambonese, word. (Ambonese is the Austronesian language of Ambon, an island of eastern Indonesia, the East Indies, in the Moluccas near Ceram.) I later found a reference in the Konciza Etimologia Vortaro: Esperanto's ailanto did indeed spring from the moluka word ailanto, which itself is a combination of ai (arbo) and lanto (ĉielo), thus ĉielarbo. (The Nova Plena Ilustrita Vortaro says that Molukoj is an Indonezia insularo.)
Ailanthus grows rapidly, achieving its mature height of 90 feet and diameter of 3 feet in little more than a decade. It is hardy to Zone 5 and grows in almost any soil and light conditions. But the Tree of Heaven is not as strong as other trees and is likely to succumb to damage by wind or ice storms by the time it is 30 years old.
Its leaves are alternate, odd-pinnately compound and deciduous. They are reddish when they unfurl in late spring but soon turn green. Fern-shaped and 1 to 3 feet in length, each consists of 11 to 31 leaflets, 3 to 5 inches long. The leaves grow in bunches at the ends of heavy twigs, creating a pattern that allows sunlight to filter through to the ground below. The leaves and flowers have an unpleasant odor when crushed, and this distinctive odor will remain on your fingers.
Even young trees have fairly large leaves. Branches do not usually appear until the tree is a few years old, and since a pinnate leaf looks rather like a branch with many small leaves upon it, the tree appears to lose all its "branches" each fall for its first few years, spending these winters as a stick. When I was young, my family used to make fun of my trees every year, calling them sticks and claiming that they'd lost all their branches.
Each tree bears flowers of one sex. If you plant only female trees they will produce seeds that are attractive - yellow/orange/red clusters from 6 to 12 inches long - but (being unpollinated) cannot develop into seedlings. Female trees are also preferable because their flowers - inconspicuous clusters of tiny yellow blossoms - lack the objectionable odor of the leaves of both sexes and the flowers of the male.
Ailanthus thrives even in poor soil. Today it is usually treated as a weed, mown down with the grass or ripped out of gardens or stone walls.
Besides ornamental uses of the living tree (shade, screen, erosion control), its wood may be used as fuel or for woodworking. The heartwood is pale green to yellow with dark streaks, while the sapwood is wide and cream color. The wood resembles ash, is easily worked with tools and glues, and takes a finish well.