Sweetgum

Liquidambar styraciflua
Family: Altingiaceae

Natural Historysweetgum
Leaves and fruits of sweetgum
Photo credit: Franklin Bonner, USFS (ret.), Bugwood.org

The sweetgum is also known as redgum, star-leaved gum, alligator-wood, and gumtree. It is easily recognized by its star-shaped leaves and its woody, spiny, ball-like fruit.

Habitat & Range

The sweetgum is a typical southern bottomland tree that occurs most abundantly on moist, rich, alluvial soils in association with many other species in valleys, swamps, and near ponds and streams. As a pioneer species, sweetgum is also common on abandoned fields and logged or clearcut areas, where it frequently forms dense thickets. It ranges from the southwestern part of Connecticut to central Florida, west to Texas and north to Southern Illinois.

Wildlife Use

The seeds of the sweetgum are eaten by birds, squirrels, and chipmunks.

Human Use

The sweetgum is a valuable commercial hardwood, second in production only to oaks among the hardwoods. The wood of sweetgum is used for many purposes, particularly veneer, furniture, flooring, interior trim, and woodenware. The wood has been distributed and sold under the trade name of "satin-walnut". The wood is also used as paper pulp and to make baskets. Pioneers once peeled the bark and scraped the resin-like solid to produce chewing gum. Sweetgum is a favorite ornamental and landscape tree due to its beautiful, glossy leaves, brilliant fall color, and because it makes a good shade tree.


 

Identifying Characteristics

Size/Form: Sweetgum is a large tree that reaches 80 to 150 feet in height, 3 to 5 feet in diameter. It is characterized as having a buttressed base with a pyramidal or oval-shaped crown.
Leaves: Leaves are simple, alternate, and deciduous. The leaves are star-shaped with 5 to 7 deeply palmate, pointed lobes. The leaf apex is long-tapered. The leaf bases are flattened or slightly heart-shaped. Leaf margins are finely serrate. Each leaf is a shiny dark green above and paler below with small hairs. Leaf petioles are slender, often 4 inches or more in length. The leaves are unpleasantly aromatic if crushed or bruised. In autumn, the leaves turn red, orange, yellow, and purple.
Twigs: The twigs are slender to moderately stout, yellowish to reddish-brown, and are aromatic. They are more or less covered with corky outgrowths, which may become large and wing-like after a season or two. The pith is homogeneous and star-shaped.
Bark: The bark on the sweetgum tree is gray and deeply furrowed, separated by narrow scaly ridges.
Flowers: The flowers are monoecious and are in head-like clusters. Female flowers produce many ovules, but only a few are fertilized to become seeds.
Fruit: The fruit is a spherical, woody head composed of many capsules. Each capsule has a pair of pointed projections ("beaks") that spread apart at maturity to release the contents. The true seeds are winged and wind-dispersed when they leave the capsules. Any remaining, unfertilized ovules are unwinged and rain down from the tree, providing food for wildlife. The fruits mature in autumn and persist on the tree throughout winter. When they fall, they persist on the ground as a spiny layer of mulch.
Similar Trees on the Florida 4-H Forest Ecology Contest List:
  • American sycamore also has spherical fruits and alternate leaves with palmate venation, but the leaves are not as deeply indented and they don't have the regular serrations along the margin.
  • Many people mistake sweetgum for a maple like Florida maple or red maple, but the leaf arrangement on those trees is opposite rather than alternate.

 

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