Ailanthus altissima (P. Mill.) Swingle
Synonym(s): ailanthus, copal tree, and stinking sumac
Tree-of-Heaven is an extremely common tree in urban areas where it can cause damage to sewers and structures but poses a greater environmental threat because of its invasiveness in cultivated fields and natural habitats. A prolific seeder, Tree-of-Heaven grows vigorously, establishing dense stands that displace native plants. It produces chemicals that kill or prevent other plants from growing in its vicinity.
In 100 Years of Change in the Distribution of Common Indiana Weeds by William and Edith Overlease (2002) reported that Tree-of-Heaven was recorded in the following Indiana counties in 1899 (Coulter’s Catalogue of Indiana Plants): Fayette, Jefferson, Marion, Monroe, and Vigo. Coulter noted that Tree-of-Heaven “escaped from cultivation very largely in some of the southern counties. I have seen whole hillsides completely covered with this species.” In 1940 (Deam’s Flora) noted that “it could be found in waste places, in cities and towns, in a few places in woodland in southern Indiana, and along the wooded bluffs of the Ohio River, especially in Jefferson County.” Deam recorded Tree-of-Heaven in Decatur, Harrison, Jefferson, Lawrence, Marion, Monroe, Montgomery, Newton, Perry, Putnam, St. Joseph, Switzerland, and Wells. In 2002, Overlease recorded that Tree-of-Heaven was found in all 92 counties in Indiana.