Американский сладкий тополь (Liquidambar styraciflua)

Tree species

American sweetgum (Liquidambar styraciflua), also known as American storax, bilsted, redgum, is a deciduous tree in the genus Liquidambar native to warm temperate areas of eastern North America and tropical montane regions of Mexico and Central America. Sweetgum is one of the main valuable forest trees in the southeastern United States, and is a popular ornamental tree in temperate climates. It is recognizable by the combination of its five pointed star shaped leaves (similar to maple leaves) and its hard, spiked fruits. It is currently classified in the plant family Altingiaceae, but was formerly considered a member of the Hamamelidaceae.

This plant's genus name Liquidambar was first given by Linnaeus in 1753 from the Latin liquidus ('fluid') and the Arabic ('amber'), in allusion to the fragrant terebinthine juice or gum which exudes from the tree. Its specific epithet styraciflua is an old generic name meaning 'flowing with storax' (a plant resin). The common name "sweetgum" refers to the species' "sweetish gum", contrasting with the blackgum (Nyssa sylvatica), only distantly related, with which the sweetgum overlaps broadly in range. The species is also known as the "redgum", for its reddish bark. The species was introduced into Europe in 1681 by John Banister, the missionary collector sent out by Bishop Compton, who planted it in the palace gardens at Fulham in London, England.

An ancestor of Liquidambar styraciflua is known from Tertiary aged fossils in Alaska, Greenland, and the mid continental plateau of North America, much further north than Liquidambar now grows. A similar plant is also found in Miocene deposits of the Tertiary of Europe. The tree is a symmetrical shape and crowns into an egg shape when the branches get too heavy after its first two years of cultivation. It is deeply fissured with scaly ridges. The branchlets are pithy, many angled, winged, and at first covered with rusty hairs, finally becoming red brown, gray or dark brown. but is difficult to season. They are long and broad, with a petiole. The rich dark green, smooth, shiny, star shaped leaves generally turn brilliant yellow, orange, red, and purple colors in the autumn. However, in the northern part of its range, and where planted in yet colder areas, the leaves are often killed by frost while still green. On the other hand, in the extreme southern or tropical parts of its range, some trees are evergreen or semi evergreen, with negligible fall color. The leaves are broad with glandular serrate teeth. The base is truncate or slightly heart shaped. They come out of the bud plicate, downy, pale green, when full grown are bright green, smooth, shining above, paler beneath. While the starry five pointed leaves of Liquidambar resemble those of some maples (Acer), Liquidambar is easily distinguished from Acer by its glossy, leathery leaves that are positioned singly (alternate), not in pairs (opposite) on the stems. Luna and promethea moth caterpillars feed on the leaves. "space bugs", "sticker balls", "spike balls", or "monkey balls". The fruit is a multicapsular spherical head and hangs on the branches during the winter. The woody capsules are mostly filled with abortive seeds resembling sawdust. Grown as an ornamental tree in Australia, Liquidambar styraciflua has a distribution on mainland Australia from southwestern Western Australia, southern South Australia, New South Wales, Victoria, and all the way up to the Atherton Tablelands in far North Queensland.

Sweetgum (Liquidambar styraciflua) is one of the most important commercial hardwoods in the Southeastern United States. Its wood is bright reddish brown (with the sapwood nearly white) and may have black grain in the heartwood; it is heavy, straight, satiny, and close grained, but not strong. It takes a beautiful polish, but warps badly in drying. The wood has a specific gravity of 0.5910. It is too liable to decay for outdoor use. and is one of the most important materials for plywood manufacturers. It is used for furniture, interior trim, railroad ties, cigar boxes, crates, flooring, barrels, woodenware, and wood pulp. It is also used for veneer for plywood. The wood is very compact and fine grained, the heartwood being reddish, and, when cut into planks, marked transversely with blackish belts. Sweetgum is used principally for lumber, veneer, plywood, slack cooperage, fuel, and pulpwood. The lumber is made into boxes and crates, furniture, cabinets for radios, televisions, and phonographs, interior trim, and millwork. The veneer and plywood, (typically backed with some other kind of wood which shrinks and warps less) are used for boxes, pallets, crates, baskets, and interior woodwork. It was formerly used in the interior finish of railroad sleeping cars. Being readily dyed black, it is sometimes substituted for ebony for such uses as inexpensive picture frames. The wood is also used to make chopsticks for the East Asian market, as it has a naturally light color with appeal to certain segments of the Asian market.

The tree's gum resin, for which the tree is named, exudes from the bark of the tree when wounded.

L. styraciflua seeds may be a renewable source of shikimic acid.

Traditionally, sweet gum has been used in Chinese medicine to treat issues such as diarrhea, coughs, and skin sores. Today, sweet gum is still being used for its many medicinal purposes. The plant possesses anti inflammatory, antioxidant, and antimicrobial properties. It has also shown antitumor action, certain enzyme inhibition, and hepatoprotective activity.

The imperfect fungus Dicarpella dryina Sutton is a leaf parasite reported to occur on a wide range of host plants, including species of sweetgum (Liquidambar styraciflua L.). Limber and Cash reported that leaf spots produced by this pathogen on several different genera of forest trees were 2–5 mm diameter with regular margins. During the summer of 1994 in the Nacogdoches County area of Texas, a prominent leaf spot on sweetgum was widespread. Infected leaves had numerous necrotic lesions, each surrounded by a reddish halo. The lesions tended to merge resulting in large areas of dead tissue. Infection and fungal development of D. dryina were investigated on leaves of sweetgum using a combination of microscopic techniques. D. dryina infection on sweetgum has been associated with the disease red leaf spot. Results of this investigation indicate that D. dryina can penetrate leaf tissue directly, thus having the ability to initiate infection on both upper and lower leaf surfaces. In other regions of the U. S., sweetgum populations may not be as susceptible to local populations of this fungus. Environmental stress factors may also be involved, as reports have indicated that herbicide application and chlorosis caused by iron deficiency may increase susceptibility of D. dryina. Tannins (a type of biomolecule found in trees to protect it from fire, insects, and bacteria) have been reported to occur in healthy tissue of a variety of plants including sweetgum. They may prevent pathogen invasion by inhibiting fungal enzyme activity. Although cells of healthy sweetgum tissue appear rich in tannins, these materials apparently were not effective in preventing fungal colonization by D. dryina.