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| Sweet Gum | ||||||||||||||
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| Liquidambar styraciflua L. |
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Liquidambar styraciflua (American Sweetgum, Redgum) is a deciduous tree in the genus Liquidambar native to warm temperate areas of eastern North America.
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Description
It is a medium-sized to large tree, growing to 20-35 m (exceptionally 41 m) tall, with a trunk up to 2 m diameter. The leaves are palmately lobed, 7-19 cm (rarely to 25 cm) long and broad and with a 6-10 cm petiole, looking somewhat similar to those of some maples. They have five sharply pointed lobes, but are easily distinguished from maples in being arranged alternately, not in opposite pairs. They are a rich dark green and glossy, and in most cases turn brilliant orange, red, and purple colors in the autumn. A small percentage of trees are evergreen or semi-evergreen, with negligible fall color, especially in the extreme southern part of its range. In the northern part of its range, as well as in colder areas that it has been planted in, the leaves are often killed by frost while still green. The roots are fibrous; juices are balsamic.
The starry five-pointed leaves of the Liquidambar suggest the Sugar Maple, and its fruit balls as they hang upon their long stems resemble those of the Buttonwood. The distinguishing mark of the tree, however, is the peculiar appearance of its small branches and twigs. The bark attaches itself to these in plates edgewise instead of laterally, and a piece of the leafless branch with the aid of a little imagination readily takes on a reptilian form; indeed, the tree is sometimes called Alligator-wood.[1]
The male and female inflorescences are on different branches of the same tree. The fruit, popularly nick-named a "space bug", "monkey ball", "bommyknocker, "bir ball, "gum ball" or "sticker ball", is a hard, dry, globose, compound fruit 2.5-4 cm in diameter and composed of numerous (20-50) capsules. Each capsule has a pair of terminal spikes, and contains one to two small seeds.
The autumnal coloring is not simply a flame, it is a conflagration; in reds and yellows it equals the maples, and in addition it has the dark purples and smoky browns of the ash.[1]
- Bark: Light brown tinged with red, deeply fissured, ridges scaly. Branchlets pithy, many-angled, winged, at first covered with rusty hairs, finally becoming red brown, gray or dark brown.
- Wood: Bright reddish brown, sapwood nearly white; heavy, straight, satiny, close-grained, not strong; will take a beautiful polish; warps badly in drying. Has been used with good results in the interior finish of sleeping-cars and fine houses. The wood is usually cut in veneers and backed up with some other variety which shrinks and warps less. Sp. gr., 0.5910; weight of cu. ft., 36.83 lbs.
- Winter buds: Yellow brown, one-fourth of an inch long, acute. The inner scales enlarge with the growing shoot, becoming half an inch long, green tipped with red.
- Leaves: Alternate, three to five inches long, three to seven inches broad, lobed, so as to make a star-shaped leaf of five to seven divisions, these divisions acutely pointed, 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. In autumn they vary in color from yellow through crimson to purple. They contain tannin and when bruised give a resinous fragrance. Petioles long, slender, terete. Stipules lanceolate, acute, caducous.
- Flowers: March to May, when leaves are half grown; monoecious, greenish. Staminate flowers in terminal racemes two to three inches long, covered with rusty hairs; the pistillate in a solitary head on a slender peduncle borne in the axil of an upper leaf. Staminate flowers destitute of calyx and corolla, but surrouned by hairy bracts. Stamens indefinite; filaments short; anthers introrse. Pistillate flowers with a two-celled, two-beaked ovary, the carpels produced into a long, recurved, persistent style. The ovaries all more or less cohere and harden in fruit. Ovules many but few mature.
- Fruit: Multicapsular spherical head, an inch to an inch and a half in diameter, hangs on the branches during the winter. The woody capsules mostly filled with abortive seeds resembling sawdust.[1]
Distribution
Sweetgum is one of the most common southern hardwoods. It occurs in the United States from southern New York west to southern Missouri and east Texas and south to central Florida, and in Mexico from southern Nuevo León south to Chiapas, as well as in Guatemala and El Salvador. In the United States it occurs at low-to-moderate altitudes, while in Mexico, Guatemala, and El Salvador it grows at higher altitudes in mountains where the climate is more temperate.
Cultivation
As well as in its native area, it has been introduced to many parts of the world, including Argentina, Australia (as far north as Brisbane), Brazil, Chile, Europe, Hawaii, Namibia, New Zealand, South Africa, Uruguay and Zimbabwe. In the United States, it is especially popular in California, where it has escaped from cultivation, and is commonly known as "liquid amber". In Florida, it is sold at least as far south as Lake Worth. In Canada, it is commonly cultivated in cities of western British Columbia such as Victoria and Vancouver. It also grows well at Toronto and Niagara Falls. Farther east, it grows as a root-hardy shrub in Ottawa and Montreal. It also grows well in New England including the states of Rhode Island, Massachusetts, Connecticut and Southeast New Hampshire. It grows best in moist, acidic loam or clay soil, and tolerates poor drainage. Salt tolerance is moderate. Chlorosis can develop on alkaline soil, especially where organic matter is low.
Selected cultivars
- 'Burgundy' – dark red to purple fall colors may persist through winter.
- 'Clydesform' - sold as Emerald Sentinel; columnar or narrowly pyramidal; slow growth to 9 meters; yellow-orange fall colors.
- 'Festival' – columnar; pale green summer leaves; bright fall hues of yellow, pink and red; less hardy than most.
- 'Goduzam' (Gold Dust) – variegated; pink to red-purple in fall.
- 'Grazam' – pyramidal, with glossy leaves. Orange, red and purple fall colors.
- 'Gumball' – dwarf shrubby cultivar seldom more than 2 meters tall. Purple-red fall color.
- 'Moraine' – upright, rounded form, fast growth, red fall color, hardy to −30 °C.
- 'Palo Alto' – various shades of red in fall; best in California.
- 'Parasol' – develops rounded crown; mature height 10 meters; deep red fall color.
- 'Rotundiloba' – sterile cultivar with rounded lobes on leaves. Originally discovered in North Carolina in the 1930s.
- 'Slender Silhouette' - very narrow columnar form.
- 'Worplesdon' – cutleaf cultivar with orange, red and purple fall colors.
Uses
American Sweetgum is a popular ornamental tree, grown for its intense fall colors, but it also has some drawbacks:
- The wood is brittle and the tree drops branches easily in storms.
- The spiked "gumballs" can be unpleasant to walk on (in fact in California they are known as "ankle biters" or "ankle twisters"), and their profusion can smother a lawn unless removed.
- Branches may have ridges or "wings" that cause more surface area, increasing weight of snow and ice accumlation on the tree.
The wood is very compact and fine-grained, the heartwood being reddish, and, when cut into planks, marked transversely with blackish belts; it is used for veneer and pulpwood, but is poor for timber or fuel. Being readily dyed black, it is sometimes used instead of ebony for picture frames, and other similar uses, but it is too liable to decay for outdoor work.
The gum resin, also known as liquid amber or copalm balsam, yielded by this tree has no special medicinal virtues, being inferior in therapeutic properties to many others of its class. It is a kind of native balsam, or resin, like turpentine. It may be clear, reddish or yellow, with a pleasant smell like ambergris. As it grows older, it hardens into a solid form, which historically was shipped to other countries in barrels. It was reputed an excellent balsam for mollifying and consolidating, and good against sciatica, weakness of the nerves, etc. Mixed with tobacco, the gum was once used for smoking at the court of the Mexican emperors. It was long used in France as a perfume for gloves and other such items. It is mainly produced in Mexico, little being obtained from trees growing in higher latitudes of North America, or in England.
An American Sweetgum will be featured as part of the Memorial Grove at the World Trade Center Memorial, with installation set for fall 2008 and spring 2009 [1].
History
The earliest record of the tree appears to be in a Spanish work by F. Hernandez, published in 1651, in which he describes it as a large tree producing a fragrant gum resembling liquid amber, whence the name. In Ray's Historia Plantarum (1686) it is called Styrax liquida. It 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.
The tree's immediate ancestor inhabited in tertiary times Alaska, Greenland and the mid-continental plateau of North America, a similar form is also found in the Miocene in Europe.[1]
References and external links
- American Sweetgum Trees
- Americas Regional Workshop (Conservation & Sustainable Management of Trees, Costa Rica, November 1996) (1998). Liquidambar styraciflua. 2006 IUCN Red List of Threatened Species. IUCN 2006. Retrieved on 12 May 2006.
- Flora of North America: genus account and species account
- USDA Plants Profile: Liquidambar styraciflua
- USFS Silvic Manual: Liquidambar styraciflua
- USGS Species Distribution Maps: Liquidambar styraciflua (pdf file).
- Liquidambar styraciflua images at bioimages.vanderbilt.edu
This article incorporates content from the 1728 Cyclopaedia, a publication in the public domain.
 Liquidambar styraciflua summer foliage cluster |
 Autumn foliage and fruit |
 Liquidambar styraciflua Mature bark of American Sweetgum Hemingway, South Carolina |
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 Liquidambar styraciflua leaves. Texas A&M University in College Station, Texas. |
 Liquidambar styraciflua at the Texas A&M University in College Station, Texas. |
 American sweetgum taken in autumn at the parc de Rentilly, France. |
