(aka Chinese Sumac)
Leaves (showing leaflets)
Family: Quassia family- Simaroubaceae
The species tolerates a wide range of
conditions but does best in mesic
environments with soils rich in loam.
It is common in disturbed sites
(considered a weed tree) and also in
urban and suburban areas in alleys,
along and through cracks in sidewalks,
parking lots, and streets. Thus, it can
be found in sites unsuitable for other
trees. Tree-of-heaven occurs, as well, in
agricultural and forest areas provided
there is not excessive shading.
Tree-of-heaven is native to eastern and
central China, Taiwan, and northern Korea.
It is an exotic and was introduced into the
United States in 1784 and is now found
across the continental U.S, the eastern
third of Canada, as well as Hawaii.
This is a rapidly growing deciduous tree
that can attain a height of 80 feet and a
diameter of 6 feet.
The alternate, large pinnately compound
leaves (on stalks of 1- 3 feet) each have
10 to 41 smaller ovate-lanceolate leaflets
2-7 inches long and 1-2 inches wide. Leaflets
are toothed only at their base and underneath
have a small gland at their tip. They are dark
green in color and, upon crushing, have an
odor much like the smell of rotting peanut
butter or rancid buttered popcorn.
Flowers are small with a pale yellow-greenish
to a red color and are bunched into large
clusters on the end of shoots. Flowers are
typically unisexual and male (foul smelling)
and female flowers occur on different
individuals (dioecy). The flowers smell like
The samaras, or winged fruits, are produced
in the summer and turn yellow to rosy red
as they ripen. The samaras grow to 1.5
inches long. The fruits last on the tree
from the summer through the winter.
The wing of the fruit is twisted and this
enables the fruit to spin rapidly when
falling from the tree to the ground.
This tree has pale gray colored bark and
the twigs of the tree are chestnut brown.
It possesses lighter vertical streaks. The
wood of the tree is soft and flaccid, having
a creamy white to a light brown color.
The “tree-of-heaven” has a very strong
root supporting system. It produces
horizontal roots capable of sprouting. With
a vast spreading root system, root sprouts
may appear as far as 50 to 90 feet from the
Ailanthus altissima is an agricultural pest
and often ecological threat. The tree grows
rapidly and is able to invade areas while
replacing native plants and creating dense
This species produces an “allelopathic”
chemical known as ailanthone that
hinders the growth of other plant species.
Roots can spread over a wide area and can
damage sewers and foundations.
It is one of the most pollution-tolerant
species of trees and resists high levels of
sulfur dioxide, ozone, and mercury.
Trees can also survive low phosphorous and
high salinity soil levels and pH levels as low
as 4.1. The ability of roots to store
considerable water aids in drought
Ailanthus altissima was first introduced
To the United States by a gardener from
Philadelphia, PA in 1784. In the 19th
century availability from nurseries and
transport and planting by Chinese
immigrants (esp. those participating in
the California goldrush) facilitated its
spread across the U.S..
The plant is also a pest in Australia and
The tree-of-heaven is mentioned in
several ancient Chinese medicinal texts
because it was believed to cure mental
illness as well as baldness. Parts of
the tree are still used in traditional
Chinese medicine as an astringent.
All parts of this tree, especially the
leaves and flowers have a nut-like or
burned nut odor.
Black Walnut (Juglans nigra)
The compound leaves of this tree look
similar to those of Ailanthus altissima
but the leaflets are finely serrated along
their margins. The fruit of black walnut
is green, large, and ball-shaped nut unlike
the samara of the tree-of-heaven, and the
bark is dark and rough.
Albright, T. P., Chen, H., Chen, L. and Guo, Q. 2010. The ecological
niche and reciprocal prediction of the disjunct distribution of an
invasive species: the example of Ailanthus altissima. Biological
Invasions. 12: 2413-2427.
De Feo, V., De Martino, L., Quaranta, E. and Pizza, C. 2003. Isolation
of phytotoxic compounds from tree-of-heaven (Ailanthus altissima
Swingle). Journal of Agricultural and Food Chemistry. 51: 1177-1180.
Hunter, J. C. 1995. Ailanthus altissima (Miller) Swingle: its biology and
recent history. California Exotic Pest Plant Council News. 3: 4-5.
Knapp, L. B.; Canham, C. D. 2000. Invasion of an old-growth forest in
New York by Ailanthus altissima: sapling growth and recruitment in
canopy gaps. Journal of the Torrey Botanical Society. 127: 307-315.
Swan, C. M., Healey, B., Richardson, D. C. 2008. The role of native riparian
tree species in decomposition of invasive tree of heaven (Ailanthus altissima)
leaf litter in an urban stream. Ecoscience. 15: 27-35.