This tree is typically 30-60' tall, forming a single trunk and a
relatively wide crown. The trunk is 1-3' across; its outer bark is gray
to brown, becoming more rough-textured and furrowed with age. The inner
bark is bright yellow, relatively soft, and corky. Twigs are brown and
smooth with scattered white lenticels, while young shoots are light
green to green and terete. Pairs of opposite compound leaves occur
along the twigs and young shoots. These leaves are odd-pinnate with
5-13 leaflets; they are 12-20" long. The petioles and rachises of the
leaves are light green, pale reddish green, or nearly white; they are
either glabrous or sparsely hairy. The leaflets are 2½-5" long and
1-1¾" across; they are lanceolate-ovate or broadly elliptic in shape,
while their margins are smooth and ciliate. The upper surface of the
leaflets is medium to dark green and glabrous, while the lower surface
is pale green and either glabrous or sparsely hairy along the veins.
The odor of crushed foliage has been variously described as
turpentine-like, skunk-like, or citrusy.
Small clusters of flowers
about 2-4" long develop among the leaves. Amur Corktree is dioecious,
producing either all male (staminate) or all female (pistillate)
flowers on separate trees. Regardless of gender, individual flowers are
about 1/8" (3 mm.) across, consisting of a short green or maroon calyx
with 5 teeth and a
yellowish green or maroon corolla with 5 lobes. Each female flower has
a pistil, while each male flower has 5 exerted stamens with bright
yellow anthers. The branches of the inflorescence are light green to
yellowish green and either glabrous or pubescent. The blooming period
late spring to early summer for about two weeks. Afterwards, the female
flowers are replaced by small globoid fruits spanning about 3/8" (1
cm.) across; these fruits are initially green, then they become
off-white, and finally blue-black or black when they are mature during
the autumn. Each fruit contains 5 seeds. The odor of the fruits is
similar to the odor of the crushed foliage (see above). The root system
spreads widely. The deciduous leaves turn yellow during the autumn.
The preference is full to partial sun, moist
but well-drained conditions, and fertile loam or silty loam.
However, young trees and saplings can tolerate considerable shade.
Individual trees can produce flowers and fruits in as little as 5 years.
The introduced Amur Corktree has rarely
cultivation in Illinois, although naturalized trees have been reported
from Dupage County in the NE section of the state (see Distribution
). Amur Corktree is native to northern China, Korea, and
it was introduced into North America as a landscape tree.
Habitats of naturalized trees consist of areas in or near parks
and open disturbed areas in urban and suburban settings. This tree is
occasionally cultivated (consisting primarily of male cultivars), and
it is considered invasive in some areas of
northeastern United States. As an invasive species, Amur Corktree can
dominate a wooded area by forming a dense mass of young trees that
shade out other plants.
Information about insect pollinators of the
unavailable for this tree. The caterpillars of a small number of
moths that are found in eastern North America are known to feed on the
(Pepper & Salt Geometer), Hyphantria
(Fall Webworm Moth), and Samia cynthia
(Ailanthus Silkworm Moth).
The fruits are spread to new areas by the Robin (Turdus migratorius
and other birds. The relatively dense crown of this tree probably
provides cover and nesting habitat for some birds.
The Toledo Botanical Garden in Toledo, Ohio. The
photographed tree is a male cultivar.
The most distinctive characteristic of this tree is the corky inner
bark; it is relatively soft and bright yellow. The compound leaves are
quite attractive, in part because they are rarely marred by insects and
disease. When the flowers of this tree are maroon, rather than
yellowish green, they stand out from the background better, creating a
more attractive display. Amur Corktree is the only species of its genus
that has naturalized in Illinois, making it fairly distinct from other
trees. While some trees within the state have alternate pinnate leaves,
Amur Corktree has opposite pinnate leaves and the petiole-scars of its
twigs are U-shaped. Later in the year, it produces dark berries that
are dispersed by birds, rather than winged seeds that are dispersed by