Ailanthus

Ailanthus is a genus of flowering plants in the family Simaroubaceae. The best known species is Ailanthus altissima, commonly called the tree of heaven. Native to China and Taiwan, it has been widely cultivated and, in many regions, escaped into the wild.

Ailanthus altissima is a fast-growing, deciduous tree that can reach heights of 15–30 meters or more. It has a stout trunk and a broad crown. Leaves are pinnate, typically 60–90 cm long, with 10–40 lanceolate leaflets 5–15 cm long. Leaflets have smooth or sparsely toothed margins; the bases carry small glands. A strong, acrid odor is produced when leaves or bark are crushed, sometimes described as similar to peanut butter.

Ecology and distribution: Ailanthus tolerates a wide range of soils and urban conditions, including drought and compacted ground. It reproduces mainly by abundant seed production; seeds are winged and dispersed by wind and animals, and can mature in a single growing season. In favorable climates, the species can form dense stands and spread into roadside, disturbed, and natural habitats.

Invasive status and impacts: In many parts of Europe and North America, Ailanthus altissima is regarded as an invasive species due to its rapid growth, high seed production, and allelopathic compounds such as ailanthone that can inhibit the germination and establishment of other plants, reducing biodiversity.

Management and uses: It is frequently targeted for removal in urban settings and protected areas. Control methods include mechanical removal of seedlings and stumps, along with herbicide treatments. Historically, the wood has been used for low-value lumber and fiber, and the tree is sometimes valued for tolerance to pollution and harsh soils, though its invasiveness limits its use.