Seasoning of Wood by Joseph Bernard Wagner (bill gates best books txt) 📕

Fig. 11. A Tupelo Gum Slough.

In the past, gum, having no marketable value, has been left standing after logging operations, or, where the land has been cleared for farming, the trees have been "girdled" and allowed to rot, and then felled and burned as trash. Now, however, that there is a market for this species of timber, it will be profitable to cut the gum with the other hardwoods, and this species of wood will come in for a greater share of attention than ever before.

38. Red Gum (Liquidamber styraciflua) (Sweet Gum, Hazel Pine, Satin Walnut, Liquidamber, Bilsted). The wood is about as stiff and as strong as chestnut, rather heavy, it splits easily and is quite brash, commonly cross-grained, of fine texture, and has a large proportion of whitish sapwood, which decays rapidly when exposed to the weather; but the reddish brown heartwood is quite durable, even in the ground. The external appearance of the wood is of fine grain and smooth, close texture, but when broken the lines of fracture do not run with apparent direction of the growth; possibly it is this unevenness of grain which renders the wood so difficult to dry without twisting and warping. It has little resiliency; can be easily bent when steamed, and when properly dried will hold its shape. The annual rings are not distinctly marked, medullary rays fine and numerous. The green wood contains much water, and consequently is heavy and difficult to float, but when dry it is as light as basswood. The great amount of water in the green wood, particularly in the sap, makes it difficult to season by ordinary methods without warping and twisting. It does not check badly, is tasteless and odorless, and when once seasoned, swells and shrinks but little unless exposed to the weather. Used for boat finish, veneers, cabinet work, furniture, fixtures, interior decoration, shingles, paving blocks, woodenware, cooperage, machinery frames, refrigerators, and trunk slats.

Red gum is distributed from Fairfield County, Conn., to southeastern Missouri, through Arkansas and Oklahoma 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. It is one of the commonest timber trees in the hardwood bottoms and drier swamps of the South. It grows in mixture with ash, cottonwood and oak (see Fig. 12). It is also found to a considerable extent on the lower ridges and slopes of the southern Appalachians, but there it does not reach merchantable value and is of little importance. Considerable difference is found between the growth in the upper Mississippi bottoms and that along the rivers on the Atlantic coast and on the Gulf. In the latter regions the bottoms are lower, and consequently more subject to floods and to continued overflows (see Fig. 11). The alluvial deposit is also greater, and the trees grow considerably faster. Trees of the same diameter show a larger percentage of sapwood there than in the upper portions of the Mississippi Valley. The Mississippi Valley hardwood trees are for the most part considerably older, and reach larger dimensions than the timber along the coast.

In the best situations red gum reaches a height of 150 feet, and a diameter of 5 feet. These dimensions, however are unusual. The stem is straight and cylindrical, with dark, deeply-furrowed bark, and branches often winged with corky ridges. In youth, while growing vigorously under normal conditions, it assumes a long, regular, conical crown, much resembling the form of a conifer (see Fig. 12). After the tree has attained its height growth, however, the crown becomes rounded, spreading and rather ovate in shape. When growing in the forest the tree prunes itself readily at an early period, and forms a good length of clear stem, but it branches strongly after making most of its height growth. The mature tree is usually forked, and the place where the forking commences determines the number of logs in the tree or its merchantable length, by preventing cutting to a small diameter in the top. On large trees the stem is often not less than eighteen inches in diameter where the branching begins. The over-mature tree is usually broken and dry topped, with a very spreading crown, in consequence of new branches being sent out.

Throughout its entire life red gum is intolerant in shade, there are practically no red seedlings under the dense forest cover of the bottom land, and while a good many may come up under the pine forest on the drier uplands, they seldom develop into large trees. As a rule seedlings appear only in clearings or in open spots in the forest. It is seldom that an over-topped 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. A scale of intolerance containing the important species, and beginning with the most light-demanding, would run as follows: Cottonwood, sycamore, red gum, white elm, white ash, and red maple.

While the red gum grows in various situations, it prefers the deep, rich soil of the hardwood bottoms, and there reaches its best development (see Fig. 10). 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 uplands 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 tap root. In the swamps, where the roots can obtain water easily, the development of the tap root is poor, and it is only moderate on the glade bottom lands, where there is considerable moisture throughout the year, but no standing water in the summer months.