AMERICAN FORESTRY 



Vol. XXII 



NOVEMBER 1916 



No. 275 



The Red Gum 



Identification and Characteristics 

 By Samuel B. Detwiler 



RED gum is one of our most attractive ornamental 

 trees, but it is equally distinguished for the excep- 

 tional beauty of its wood. It has many names. 

 Sweet gum and Liquidambar are names that are applied 

 on account of the fragrant resin which exudes from the 

 bark. Star-leaf gum and red gum are given because of 

 the shape and rich fall coloring of the leaves. Bilsted, 

 alligator tree, satin walnut, Circassian walnut and hazel- 

 wood are other names occasionally bestowed upon it. 

 Red gum is not closely related to the black gum and 

 tupelos, but belongs to the Witch Hazel family. There 

 are three related species, one being found in Mexico, 

 one in central China, and the third in the Levant. The 

 latter furnishes the liquid storax of commerce. 



The home of the red gum is the region lying south 

 of a line drawn from southern Connecticut through 

 southeastern Missouri and northwestern Arkansas to the 

 Trinity River, Texas. It is most abundant and reaches 

 its greatest size in the lower Mississippi Valley and the 

 lowlands of the southeastern coast. It is a tree that 

 prefers rich moist soil and suffers no harm when the 

 land is flooded for part of the year, but it does not 

 develop well in the perma- 

 nent swamps where tupelo 

 and cypress thrive. In the 

 bottomlands it is usually 

 found mixed with red 

 maple, elm, ash, cottonwood 

 and oaks. It grows on 

 high land, but on dry soil 

 the trees are of smaller size. 

 The largest red gum trees 

 are 5 feet in diameter and 

 150 feet high. Average- 

 sized mature trees are \ l /i 

 feet to 3 feet across the 

 stump and 80 to 120 feet 

 high. In the forest the 

 trunk is straight and clear 

 of side branches far above 

 the ground. Near the top 

 it forks and forms a spread- 

 ing crown. Young trees 

 growing in the open have a 

 long and very regular coni- 

 cal top. The bark on old 



AREA OF RED GUM TREE GROWTH 

 Red gum (.Liquidambar styraciflua) is distributed from Fairfield County, 

 Connecticut, to southeastern Missouri, through Arkansas and the Indian 

 Territory to the valley of the Trinity River in Texas, and eastward to the 

 Atlantic' Coast. Its commercial range is restricted, however, to the moist 

 lands of the lower Ohio and Mississippi basins and of the southeastern coast. 

 While the red gum grows in various situations, it prefers the deep, rich soil of 

 the hardwood bottoms, and there reaches its best development. It requires 

 considerable soil moisture, though it does not grow in the wetter swamps, and 

 does not thrive on dry pine land. Seedlings, however, are often found in large 

 numbers on the edges of the upland and even on the sandy pine land, but they 

 seldom live beyond the pole stage ; when they do, they form small, scrubby trees 

 that are of little value. Where the soil is dry the tree has a long taproot. In 

 the swamps, where the roots can obtain water easily, the development of the 

 taproot is poor, and it is only moderate on the glade bottomlands, where there 

 is considerable moisture throughout the year, but no standing water in the 

 summer months. 



trunks is grayish brown, tinged with red; it is thick (I 

 to \ l / 2 inches) and deeply furrowed into broad ridges 

 which are covered with many small scales. Young trees 

 have ashy gray trunks and frequently are covered with a 

 hard, warty growth of bark from which the tree derives 

 the name alligator wood. 



The twigs are rather heavy and somewhat angular, 

 and in the second year, peculiar blade-like ridges of cork 

 appear on them, affording an easy means of recognizing 

 this tree. The smaller branches of bur oak and cork 

 elm have somewhat similar corky wings, but the bark 

 between the corky ridges is not smooth and shining as is 

 the case with the red gum twigs. The lustrous brown 

 buds are about one-fourth inch long and are generally 

 sharp-pointed. The alternately placed leaves are 5 to 7 

 inches long, and are usually cut into five points shaped 

 like a six-pointed star with one point missing where the 

 stem is attached. Occasionally the leaves have 7 instead 

 of 5 points. They are bright green and glossy on the 

 upper surface and somewhat paler beneath. When 

 the leaves, twigs and buds are crushed, they have the 

 same delightful fragrance as the resin which oozes 



from wounds in the bark 

 of red gum trees growing 

 in the South. 



The flowers appear in 

 March in the South and in 

 April or May in the North, 

 at the time the leaves are 

 half grown. The greenish 

 pollen - producing flowers 

 are borne in dense clusters 

 2 or 3 inches long at the 

 ends of the twigs. Each 

 flower consists of a num- 

 ber of stamens clustered 

 together and surrounded by 

 small, hairy, leaf-like scales. 

 The seed-producing flowers 

 are greenish balls that hang 

 singly on long threads at 

 the bases of the upper 

 leaves of the twigs. The 

 seed balls are 1 to lJ/2 inches 

 in diameter and ripen their 

 seed in the fall but remain 

 641 



