RED GUM
(Liquidambar Styraciflua)

This tree does not belong to the same group as black gum and tupelo, which are in the dogwood family, while red gum is of the witch hazel family. If a tree is to be judged and named by its character, red gum is more entitled to the name “gum” than any other tree of this country, because it exudes a yellow resin from wounds in the bark. The botanical name recognizes that fact. Storax is procured from a closely related tree is Asia, and has been known in commerce for many centuries. The other popular names of red gum are sweet gum, liquid-amber gum, gum tree, alligator wood, bilsted, starleaved gum, and satin walnut.

The last name originated in England where it was desirable to avoid the name gum when applied to the wood of this tree. Though botanically it is about as distantly related to walnut as any tree can be, the figure of the wood often suggests walnut. The name sweet gum refers to the pleasant odor of the resin which is sometimes used in France, and probably elsewhere, to perfume gloves. Alligator wood is descriptive of warty excrescences on the bark of some trees, but they are not common to all. Starleaved gum relates to the leaf. It is a lopsided star—a six point star with one point missing.

This tree’s range in the United States extends from Connecticut to Texas and as far northwest of the Alleghanies as Missouri and Illinois. It reaches its greatest size in the lower Mississippi valley in rich bottom land which is subject to repeated inundation. It is not, however, as purely a swamp tree as tupelo and cypress. It grows well on land which is never inundated, but it needs plenty of moisture. The largest specimens exceed a height of 120 feet and a diameter of four; but logs from eighteen inches to three feet are the usual sizes. The tree’s range extends southward through Mexico into Central America.

The rise of red gum lumber into prominence forms an interesting chapter in the industry. It was formerly considered so difficult to season that few mills cared to deal with it, but that difficulty has been largely overcome. In the past, gum, having no market value, was left standing after logging; or, where the land was cleared for farming, was girdled and allowed to rot, and then felled and burned. Not only were the trees a total loss to the farmer, but, from their great size and the labor required to handle them, they were so serious an obstruction as often to preclude the clearing of valuable land. Now that there is a market for the timber, it is profitable to cut gum with other hardwoods, and land can be cleared more cheaply. This increase in the value of gum timber will be of great benefit to the South in many ways.

Throughout its entire life red gum is intolerant of shade. As a rule seedlings appear only in clearings or in open spots in the forest. It is seldom that an overtopped tree is found, for the gum dies quickly if suppressed, and is consequently nearly always a dominant or intermediate tree. In a hardwood bottom forest, the timber trees are all of nearly the same age over considerable areas, and there is little young growth to be found in the older stands. The reason for this is the intolerance of most of the swamp species.

Red gum reproduces both by seed and by sprouts, fairly abundantly every year, but about once in three years there is a heavy production. In the Mississippi valley the abandoned fields on which young stands of red gum have sprung up are, for the most part, being rapidly cleared again. The second growth here is considered of little worth in comparison with the value of the land for agricultural purposes.

A large amount of red gum growing in the South can be economically transported from the forests to the mills only by means of the streams, owing to the expense of putting in railroads solely for handling the timber. Green red gum, however, is so heavy that it scarcely floats and, to overcome this difficulty, various methods of driving out the sap before the logs are thrown into the river have been tried. One method is to girdle the trees and leave them standing a year. That partly seasons them, but does not give time for the sapwood to decay. The logs from such trees float readily, and the swamps and streams are utilized to carry the logs to the mills.

Some years ago that method of seasoning red gum was extensively advertised in England by contractors who sold paving blocks of this wood. It was claimed that the common defects of red gum were thus overcome. Large sales of paving material were made, particularly in London, and red gum was popular for a time, but it finally lost its hold as a paving wood in competition with certain Australian woods. The theory that by girdling a tree and allowing it to die, the amount of heartwood will be increased has been abandoned. In selecting trees for cutting, those with doty tops, rotten stumps, and heavy bark, indications of an old tree which contains a very small proportion of sapwood, are now chosen. These are found mainly in the drier localities. In low, wet places the trees have more sapwood and are smaller. The heartwood forms while the tree is living, not after it dies.

The rapidity with which red gum has come into use in this country and elsewhere is the best evidence of the wood’s real value. Its range of uses extends from the most common articles, such as boxes and crates, to those of highest class, like furniture and interior finish. It is only moderately strong and stiff, and is not a competitor of hickory, ash, maple, and oak in vehicle manufacturing and other lines where strength or elasticity is demanded; but in nearly all other classes of wood uses, red gum has made itself a place. It has pushed to the front in spite of prejudice. As soon as the difficulties of seasoning were mastered, its victory was won. Its annual use in Michigan, the home and center of hardwood supply, exceeds 20,000,000 feet in manufactured articles, exclusive of what is employed in rough form. In Illinois, the most extensive wood-manufacturing state in the Union, red gum stands second in amount among the hardwoods, the only one above it being white oak. In Kentucky, only white oak and hickory are more important among the factory woods, while in Arkansas, where the annual amount of this wood in factories exceeds 100,000,000 feet, it heads the list of hardwoods.

As a veneer material, it is demanded in four times the quantity of any other species. The veneer is nearly all rotary cut, and it goes into cheap and expensive commodities, from berry crates to pianos.

The wood weighs 36.83 pounds per cubic foot. It is straight-grained, the medullary rays are numerous but not prominent, the pores diffuse but small, and the summerwood forms only a narrow band, like a line. The annual rings do not produce much figure, but wood has another kind of figure, the kind that characterizes English and Circassian walnuts, smoky, cloudy, shaded series of rings, independent of the growth rings. They have no definite width or constant color, but the color is usually deeper than the body of the wood. This figure is one of the most prized properties of red gum. It is that which makes the wood the closest known imitator of Circassian walnut.

All red gum is not figured, and that which is figured may be worked in a way to conceal or make little use of the figure. It shows best in rotary cut veneer and tangentially sawed lumber. Various woods are imitated with red gum. It is stained or painted to look like oak, cherry, mahogany, and even maple.

Some trees have thin sapwood, and others are all sapwood. This peculiarity sometimes leads to misunderstandings in lumber transactions. A buyer specifies red gum, expecting to get red heartwood, but the seller delivers lumber cut from the red gum tree, though light colored sapwood may predominate. Properly speaking, the name is applied to the tree as a whole and does not refer to any particular color of wood in the tree. The term “red” is said to have referred originally to the color of autumn leaves, and not to the wood.

The fruit of red gum is a bur, midway in appearance and size between the sycamore ball and the chestnut bur. It hangs on the tree until late in winter. The resin which exudes from wounds in the bark is of much commercial importance and is shipped from New Orleans and Mexican ports. Near the northern limit of the species’ range the trees yield little resin, but it is abundant farther south. In the southern states it is used locally as chewing gum. It is known commercially as copalm balm.