Ailanthus altissima

Tree of Heaven

Botanical description: Introduced to the US for ornamental purposes in the 18th century, tree of heaven is the most ubiquitous weed tree species and is generally found in forgotten urban niches where other plants would struggle for survival. The tree was famously used as a poignant metaphor in Betty Smith’s, “A Tree Grows in Brooklyn” for its ability to adapt and tolerate adverse growing conditions. Ailanthus altissima can release chemicals through its roots that can inhibit the growth of other species. The plant’s ability to grow quickly, six feet or more a year in the northeast, renders it an important urban tree, and powerful carbon capturing species. Capitalizing on the plant’s fast growth and tenacity, Ailanthus has also been used in phytoremediation tests in which the tree’s roots slowly remove toxins from the soil and store it in its woody mass. Although New York State recognizes Ailanthus as an invasive species, it has an historical record of providing other human and ecological services, such as shade in underserved neighborhoods. The tree possesses compound leaves that imbue it with a tropical appearance, especially when its dense seed clusters turn coral in late July. The numerous seeds spiral around in the air as they ripen later in the autumn.