Celtis occidentalis, commonly known as the听common hackberry, is a large听听听native to North America. It is also known as the听nettletree,听sugarberry,听beaverwood,听northern hackberry, and听American hackberry.听It is a moderately long-lived听听with a light-colored wood, yellowish gray to light brown with yellow streaks.
The common hackberry is easily distinguished from elms and听some听other hackberries by its cork-like bark with wart-like protuberances. The leaves are distinctly asymmetrical and coarse-textured. It produces small fruits that turn orange-red to dark purple in the听, often staying on the trees for several months. The common hackberry is easily confused with the听听(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
The common hackberry is a medium-sized tree, 9 to 15 metres (30 to 50 ft) in height,听with a slender trunk. In the best conditions in the southern听听area, it can grow to 40 metres (130听ft). It 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.听In the western part of its range, trees may still grow up to 29听m (95听ft).听The maximum age attained by hackberry is probably between 150 and 200 years in ideal conditions.
The听听is light brown or silvery gray, broken on the surface into thick听听scales and sometimes roughened with excrescences; the pattern is very distinctive.听The remarkable bark pattern is even more pronounced in younger trees, with the irregularly-spaced ridges resembling long geologic palisades of听 [layered] rock formations when viewed edge-wise [cross-section]. Coins as large as U.S. quarters can easily be laid flat against the valleys, which may be as deep as an adult human finger.
The branchlets are slender, and their color transitions from light green to red brown and finally to dark red-brown. The winter听听are听,听,听, somewhat flattened, one-fourth of an inch long, light brown. The bud scales enlarge with the growing shoot, and the innermost become听. No terminal bud is formed.
The leaves are听听on the branchlets,听听to ovate-, often slightly听,听5鈥�12听cm (2鈥�4+3鈦�4听in) long by听3鈥�9听cm (1+1鈦�4鈥�3+1鈦�2听in),听very听听at the base, with a pointed tip. The听听is听听(toothed), except at the base which is mostly听听(smooth). The leaf has three听, the听听and primary veins prominent. The leaves come out of the bud听听with slightly听听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.听听slender, slightly grooved, hairy. Stipules varying in form,听.
The flowers are greenish and appear in May, soon after the leaves. They are听, meaning that there are three kinds:听听(male),听听(female),听听(both female and male). They are born on slender drooping听.
The听听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,听听in bud. There is no听.
There are five stamens, which are听; the听听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;听听, oblong, two-celled; cells opening longitudinally.
The pistil has a two-lobed听听and one-celled听听containing solitary听.
The fruit is a fleshy, oblong听,听1鈦�4听to听3鈦�8听in (0.64 to 0.95听cm) long, tipped with the remnants of style, dark purple when ripe. It is borne on a slender stem and ripens in September and October. It remains on the branches during winter.听The endocarp contains significant amounts of biogenic carbonate that is nearly pure听.
Distribution and habitat
The common hackberry is native to North America from听听and听, through parts of听, south to听-(), west to northern听, and north to听.听There is a small isolated pocket at the southern end of听.听Hackberry's range overlaps with the听听(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听听(Celtis reticulata), which has a similar bark. Hackberry grows in many different habitats, although it prefers bottomlands and soils high in听. Its听听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
The leaves are eaten by four gall-producing insects of the 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,听including robins and听,听and mammals. Most seeds are dispersed by animals, but some seeds are also dispersed by water.
The tree serves as a butterfly larval host, particularly the听听and the听.
Conservation
Celtis occidentalis听was evaluated by听听16 August 2016. During that review they evaluated it as "secure", G5, with a very low risk of extinction due to an extensive range and little or no concern due to declines.
Cultivation and uses
Hackberry's wood is light yellow; heavy, soft, coarse-grained, not strong. It rots easily, making the wood undesirable commercially, although it is occasionally used for fencing and cheap furniture.
Hackberry is only occasionally used as a street or landscape tree, although its tolerance for urban conditions makes it well suited to this role.听听in听听and听, the capital of听, are known for the extensive use of hackberry (in the latter case along with closely related but Eurasian听) as a street tree.
The tree's pea-sized berries are edible, ripening in early September. Unlike most fruits, the berries are remarkably high in calories from fat, carbohydrate, and protein, and these calories are easily digestible without cooking or preparation.听Omaha Native Americans ate the berries casually, while the Dakota used them as a flavor for meat, pounding them fine, seeds and all. The Pawnee also pounded the berries fine, added a little fat, and mixed them with parched corn.