Celtis occidentalis

Celtis occidentalis
Scientific classification
Kingdom:	Plantae
(unranked):	Angiosperms
(unranked):	Eudicots
(unranked):	Rosids
Order:	Rosales
Family:	Cannabaceae
Genus:	Celtis
Species:	C. occidentalis
Binomial name
Celtis occidentalis L.[1]
Native range of Celtis occidentalis

Celtis occidentalis, commonly known as the Common hackberry, is a large deciduous tree native to North America. It is also known as the nettletree, beaverwood, northern hackberry, and American hackberry.^[2] It is a moderately long-lived^[2] hardwood^[2] with a light-colored wood, yellowish gray to light brown with yellow streaks.^[3]

The common hackberry is easily distinguished from elms and some other hackberries by its cork-like bark with wart-like protuberances. The remarkable bark pattern is even more pronounced in younger trees, with the irregularly-spaced ridges resembling long geologic palisades of sedimentary [layered] rock formations when viewed edge-wise [cross-section]. Coins as large as USA quarters can easily be laid flat against the valleys, which may be as deep as an adult human finger.

The leaves are distinctly asymmetrical and coarse-textured. It produces small berries that turn orange-red to dark purple in the autumn, often staying on the trees for several months. The common hackberry is easily confused with the sugarberry (Celtis laevigata) and is most easily distinguished by range and habitat. The common hackberry also has wider leaves that are coarser above than the sugarberry.

Description

Bark

Usually the common hackberry forms a medium sized tree, thirty to fifty feet in height,^[2] with a slender trunk; however, it can rise to the height of one hundred and thirty feet, in the best conditions in the southern Mississippi valley area. In the middle states of its range it seldom attains a height of more than sixty feet, and has a handsome round-topped head and pendulous branches. It prefers rich moist soil, but will grow on gravelly or rocky hillsides. The roots are fibrous and it grows rapidly.^[4] In the western part of its range with less rainfall and poorer soils it normally averages about thirty feet in height, but at least one specimen was found at ninety five feet.^[2] The maximum age attained by hackberry is probably between 150 and 200 years in ideal conditions.^[2]

Hackberry tree on the campus of the University of Chicago.

The bark is light brown or silvery gray, broken on the surface into thick appressed scales and sometimes roughened with excrescenses; pattern is very distinctive.

Close-up of hackberry bark.

The branchlets are slender, light green at first, finally red brown, at length become dark brown tinged with red. The winter buds are axillary, ovate, acute, somewhat flattened, one-fourth of an inch long, light brown. Scales enlarge with the growing shoot, the innermost becoming stipules. No terminal bud is formed. The leaves are alternately arranged on stems, ovate to ovate-lanceolate, more or less falcate, two and a half to four inches (102 mm) long, one to two inches wide, very oblique at the base, serrate, except at the base which is mostly entire, acute. Three-nerved, midrib and primary veins prominent. They come out of the bud conduplicate with slightly involute margins, pale yellow green, downy; when full grown are thin, bright green, rough above, paler green beneath. In autumn they turn to a light yellow. Petioles slender, slightly grooved, hairy. Stipules varying in form, caducous.

Leaf

The flowers appear in May, soon after the leaves. Polygamo-monœ cious, greenish. Of three kinds—staminate, pistillate, perfect; born on slender drooping pedicels. The calyx is light yellow green, five-lobed, divided nearly to the base; lobes linear, acute, more or less cut at the apex, often tipped with hairs, imbricate in bud.

• Corolla: Wanting.

There are five stamens, which are hypogynous; the filaments are white, smooth, slightly flattened and gradually narrowed from base to apex; in the bud incurved, bringing the anthers face to face, as flower opens they abruptly straighten; anthers extrorse, oblong, two-celled; cells opening longitudinally.

• Pistil: ovary superior, one-celled; style two-lobed; ovules solitary.
• Fruit: Fleshy drupe, oblong, one-half to three-fourths of an inch long, tipped with remnants of style, dark purple. Borne on a slender stem; ripens in September and October. Remains on branches during winter.^[4]

Distribution and habitat

The common hackberry is native to North America from southern Ontario and Quebec, through parts of New England, south to North Carolina-(Appalachia), west to northern Oklahoma, and north to South Dakota. Hackberry's range overlaps with the sugarberry (Celtis laevigata), making it difficult to establish the exact range of either species in the South. Although there is little actual overlap, in the western part of its range the common hackberry is sometimes confused with the smaller netleaf hackberry (Celtis reticulata), which has a similar bark. Hackberry grows in many different habitats, although it prefers bottomlands and soils high in limestone. Its shade tolerance is greatly dependent on conditions. In favorable conditions its seedlings will persist under a closed canopy, but in less favorable conditions it can be considered shade intolerant.

Ecology

Fruits

Hackberry is highly susceptible to fire damage. The leaves are eaten by four gall-producing insects of the Pachypsylla genus, which do not cause serious damage to the tree. A number of insects and fungi cause rapid decay of dead branches or roots of the tree.

The small berries, hackberries, are eaten by a number of birds and mammals. Most seeds are dispersed by animals, but some seeds are also dispersed by water.

Cultivation and uses

The wood is light yellow; heavy, soft, coarse-grained, not strong. Used for fencing and cheap furniture. Sp. gr., 0.7287; weight of cu. ft., 45.41 lb (20.60 kg).

Hackberry's wood is soft and rots easily, making the wood undesirable commercially, although it is occasionally used for furniture or other uses. The berries, although edible, are small and out of reach, and are seldom eaten by humans. Hackberry is only occasionally used as a street or landscape tree, although its tolerance for urban conditions make it well suited to this role. Ridjica and Sombor in Serbia (where it is called kustelic or galagunja) and Bratislava, the capital of Slovakia, is known for the extensive use of hackberry as a street tree.

References

External links

Wikimedia Commons has media related to Celtis occidentalis.

• USDA Forest Service Silvics Manual - Hackberry
• Flora of North America, Profile and map: C. occidentalis
• RangeMap:
• Celtis occidentalis images at bioimages.vanderbilt.edu