Читать книгу Seasoning of Wood - J. B. Wagner - Страница 54

This general term applies to three important species of gum in the South, the principal one usually being distinguished as "red" or "sweet" gum (see Fig. 10). The next in importance being the "tupelo" or "bay poplar," and the least of the trio is designated as "black" or "sour" gum (see Fig. 11). Up to the year 1900 little was known of gum as a wood for cooperage purposes, but by the continued advance in price of the woods used, a few of the most progressive manufacturers, looking into the future, saw that the supply of the various woods in use was limited, that new woods would have to be sought, and gum was looked upon as a possible substitute, owing to its cheapness and abundant supply. No doubt in the future this wood will be used to a considerable extent in the manufacture of both "tight" and "slack" cooperage. In the manufacture of the gum, unless the knives and saws are kept very sharp, the wood has a tendency to break out, the corners splitting off; and also, much difficulty has been experienced in seasoning and kiln-drying.

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.