SIMAROUBACEAE - - Quassia Family

* Ailanthus altissima (P. Miller) Swingle — Tree-of-Heaven

*This tree is not native to the United States

Tree-of-Heaven (Ailanthus altissima) is a short to medium-size tree, growing to a maximum of 82 feet, with a loose, open crown, well-rounded even when young; trunk slender, up to 3.3 feet in diameter, often many small trees found growing together in clumps. The National Champion has a circumference of 254 inches, a height of 54 feet, and a crown spread of 53 feet. The Tree-of-Heaven is extremely fast growing, up to 12 feet, in a single season. It was originally selected as an urban tree because of its rapid growth rate and ability to withstand the stresses of cities. However, once it becomes established, this tree is very difficult to rout, and as a consequence is now considered an invasive weed.

Separating Characteristics

Leaves are alternate, deciduous, odd pinnately compound with 11-41 leaflets. The leaves release a powerful odor when crushed or picked from the stem, which has been described as something like popcorn with rancid butter poured over it. The rachis of leaves are not winged; leaflets entire except for 2 or more course, glandular teeth near the base. Certain trees bear only male flowers (also odoriferous); others also have perfect ones that develop into the fruit. The fruit often occurs in great masses on the tree and looks something like a crude propeller, with a twisted wing and central seed cavity. The twigs are very stout, with large conspicuous leaf scars and reddish pith.

Habitat

Roadsides, forests, disturbed areas, including cities, especially in moist, fertile soils; native of e. Asia. In our area, this tree is now an aggressive and noxious weed, colonizing even undisturbed forests and outcompeting the native vegetation. It can be recognized vegetatively by its large pinnately compound leaves, very stout twigs (often over 1 cm thick), and the characteristic and unpleasant odor of the crushed foliage. Ailanthus altissima is not native to the United States, but has found a niche in our flora by growing in some of the most inhospitable conditions imaginable and will grow in poor, hard, tramped, or sunbaked earth, where not many (or any) native trees will grow. It has even been observed to grow in cracks on the sides or rooftops of buildings and cracks in bricks, concrete, etc. But, to me, another non-native tree, Royal Paulownia (Paulownia tomentosa), will grow in an even more hostile environment than Tree-of-Heaven.

Habitat information from:
Weakley, Alan S., Flora of the Southern and Mid-Atlantic States, Working Draft of 21 May 2015.

Range

This tree has been reported from Canada south to Florida, west to California and north to Washington. The only states where it hasn't been reported are Vermont, New Hampshire, Minnesota, North Dakota, South Dakota, Wyoming and Montana.

The range of Ailanthus altissima (Tree-of-Heaven)

Kartesz, J.T., The Biota of North America Program (BONAP). 2015. North American Plant Atlas. (http://bonap.net/napa). Chapel Hill, N.C. [maps generated from Kartesz, J.T. 2015. Floristic Synthesis of North America, Version 1.0. Biota of North America Program (BONAP). (in press)].

The Georgia range of Ailanthus altissima (Tree-of-Heaven)

Zomlefer, W.B., J.R. Carter, & D.E. Giannasi. 2014 (and ongoing). The Atlas of Georgia Plants. University of Georgia Herbarium (Athens, Georgia) and Valdosta State University Herbarium (Valdosta, Georgia). Available at: http://www.georgiaherbaria.org/.