The wood is not hard, but is moderately strong, and stiff. It has been compared with hickory, but it is so inferior in almost every essential that no comparison is justified.
Black gum weighs 39.61 pounds per cubic foot. It is very porous, but the pores are too small to be seen by the naked eye, and are diffused through the wood and form no distinct lines or groups. The summerwood is a thin dark line, not prominent enough to clearly delimit the yearly rings of growth. The medullary rays are numerous, but very thin. In quarter-sawed wood they produce a luster, but the individual rays are practically invisible. The wood is not durable in contact with the soil.
The standing tree is apt to fall a victim to the agencies of decay. Hollow trunks, mere shells, are not uncommon. The entire heartwood is liable to fall away. The pioneers cut these hollow trees, and sawing them in lengths of about two feet, made beehives of them. They called them gums because they were cut from gum trees. Larger sizes, used in place of barrels, were also called gums, but these were usually made from sycamores. The black gum is not usually large. Individuals have been measured that were five feet in diameter and more than a hundred in height, but an average of sixty feet high and two in diameter is probably too much, except in the southern Appalachian mountains where the species attains its largest size.
It is a tree which will always be easily recognized after it has been seen and identified once. Its general outline, particularly when leaves are off, is different from other trees associated with it. It might possibly be mistaken for persimmon unless looked at closely; but there are easily-recognized points of difference. Its branches are very small, slender, and short. Its bark is rougher than that of any other gum, and is much darker in color. It is the bark’s color that gives the tree its name. The leaves have smooth edges. In the fall they change to gorgeous red, and one of their peculiarities is that half a leaf may be red while the other half remains green. Toward the end of the season, the green disappears. The dark blue drupes ripen in October. They do not seem to be food for any living creature.