Читать книгу American Forest Trees - Henry H. Gibson - Страница 15

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In the markets the lumber of this species is known as yellow pine, southern yellow pine, and sap pine, and in some localities the term shortleaf is used. The latter is descriptive, and can be easily understood when reference is made to the living tree, because its short needles distinguish it from its associates in the pine forest; but in speaking of lumber only, the reference to the leaves has less meaning, particularly to one who is not acquainted with the tree’s appearance. Its wood so closely resembles that of Cuban and loblolly pine that they are not easily distinguished by sight alone. In the East the name Carolina pine or North Carolina pine is much used, but it is not often heard west of the Allegheny mountains. Referring to the manner and locality of its growth it is called slash pine in North Carolina and Virginia, old-field pine in Alabama and Mississippi, and poor-field pine in Florida. Its tendency to take possession of abandoned ground has given it these names. It is occasionally called pitch pine in Missouri. That name would not distinguish it in most parts of the South where several species of pitch pine grow. In some regions it is known as spruce pine, but the name is not based on any characteristic of the living tree or of its wood. In North Carolina and Alabama, and in literature, it is sometimes known as rosemary pine, but that name applies rather to fine timber cut from any southern yellow pine, than to this species in particular. In Delaware it is known as shortshat and in Virginia as bull pine. To those who are familiar with the tree’s appearance, the name shortleaf pine is most accurate in definition.

The commercial range of shortleaf pine has contracted to a considerable extent since the settlement of the country. It once grew as far north as Albany, New York, and from fifty to a hundred years ago it was lumbered in Pennsylvania, Maryland, and West Virginia in regions where it has now ceased to exist, or is found only as scattered trees. Its geographical range is now usually given from New York to Florida, west to Missouri and Oklahoma and northeastern Texas. It is important in lumber operations in North Carolina and southward, and westward to the limits of its range. The tree reaches its largest size and attains its finest stands west of the Mississippi river. In average size it exceeds longleaf pine. It may reach a height above 100 feet and a trunk diameter of three or four. Squared timbers of large size were formerly exported from Virginia and North Carolina. Similar sizes cannot now be procured there.

Shortleaf pine varies greatly in the quality and amount of sapwood. It is normally a thick sap tree, but midway between loblolly and longleaf. The young tree increases rapidly in size until it is from six to ten inches in diameter, and the yearly rings are wide. The rate of growth then decreases and during the rest of its life the rings are narrow. This feature is often of assistance in identifying southern yellow pine logs or large timbers which contain the heart and also the sap. Wide rings near the heart, followed by narrow ones, and a thick sapwood are pretty good evidence that the timber—if a southern yellow pine—is shortleaf pine. The rule is not absolute; for a high authority on timber has said that no infallible rule can be laid down for distinguishing by sight alone the woods of the four southern yellow pines—longleaf, shortleaf, Cuban, and loblolly.

The wood of shortleaf pine is strong, heavy, hard, and compact; very resinous, resin passages large and numerous; medullary rays numerous, conspicuous; color, orange, the sapwood nearly white. The thoroughly seasoned wood weighs thirty-eight pounds per cubic foot. It is about five pounds heavier than loblolly pine, five pounds lighter than longleaf, and nearly nine pounds lighter than Cuban pine. There is so great a variation in weight of shortleaf pine that only general averages have value.

Shortleaf pine is not as strong as longleaf, and is not so extensively employed in heavy structural work, but in certain other lines it has the advantage of longleaf. It is softer, and door and sash makers like it better. It is easier to work, and when manufactured into doors and interior finish many consider it superior to longleaf. The wide rings of annual growth in the heartwood show fine contrast in color, and when these are developed by stains and fillers, the grain or figure of the wood is very pleasing. Where hardness is not an essential, it is much used for floors. It is in great demand by builders of freight cars, but less for frames and heavy beams than for siding and decking. Car builders in Illinois bought 77,000,000 feet of it in 1909. That was nearly half of the entire quantity of this wood used in the state. The second largest users in Illinois were manufacturers of sash, doors, blinds, and general millwork. If the whole country is considered, this is probably the largest use of the wood. Makers of boxes and crates in the South employ large quantities.

The depletion of shortleaf forests has progressed rapidly, but in the absence of reliable statistics it is impossible to give figures by decades or years. In 1880 an estimate placed the amount west of the Mississippi at 95,000,000,000 feet. That was probably less than half of the country’s supply at that time. In 1911 the Commissioner of Corporations estimated that the combined remaining stand of loblolly and shortleaf pine in the South was 152,000,000,000 feet. It is doubtful if half of it was shortleaf. In that case, there was less shortleaf pine in the entire South in 1911 than there was west of the Mississippi river thirty years before.

Rapid decrease in total stand of a species does not necessarily imply exhaustion. The cut will fall off as scarcity pinches. In the case of shortleaf pine, an influence is active which will bring good results in the future. This pine reproduces with vigor. Its small triangular seeds are equipped with wings which carry them into vacant areas where they quickly germinate if they fall on mineral soil. The seedling trees suffer much from fire, but their power of resistance is fairly good, and dense new growth is coming on in many localities. A good many years are required to bring a seedling to maturity, but it will reach sawlog size sometime, and there is no question but that the market will welcome it.

The shortleaf pine is peculiar among eastern softwoods in one respect. Stumps will sprout. That occurs oftener west of the Mississippi than east. However, the tree’s ability to send up sprouts from the stump is of little practical value, since the sprouts seldom or never develop into merchantable trees. In that respect it differs from the other well-known sprouting softwood of this country, the California redwood, whose numerous sprouts grow into large trunks.

Spruce Pine (Pinus glabra). This is one of the softest and the whitest of the hard pines of this country. Nothing but its scarcity stands in the way of its becoming an important timber tree. The best of it is a satisfactory substitute for white pine in the manufacture of doors. It grows rapidly, and the wide rings contain a high percentage of light colored springwood, though there is enough summerwood of darker color to give the dressed lumber a character. It weighs about the same as northern white pine, but is weaker. In South Carolina and Florida it is called white pine, but the name spruce is more general. It is known also as kingstree, poor pine, Walter’s pine, and lowland spruce pine. Its range is restricted to southern South Carolina, northern Florida and southern Alabama and Mississippi, and northeastern Louisiana. Its leaves are from one and a half to three inches in length, grow two in a bundle, and fall the second and third years. Large and well-formed trunks attain a height of from eighty to 100 feet and a diameter from two to nearly three. It reaches its best development in northwestern Florida, and its light, symmetrical trunks have long been in use there as masts for small vessels. It is too scarce to attract much attention from lumbermen, but they are well acquainted with its good qualities, and some of them take pains to keep the lumber separate from associated pines, and sell it to manufacturers of doors and interior finish. The bark bears considerable resemblance to spruce, which probably accounts for the name of the tree.

Table Mountain Pine (Pinus pungens). The French botanist, Michaux the younger, has been criticized for the statement which he made more than a hundred years ago that this species was confined to a certain flat-topped mountain in the southern Appalachian ranges, and he called it table mountain pine. It lacked much of being confined within the narrow limits where it was discovered. It grows in New Jersey, Pennsylvania, Maryland, District of Columbia, Virginia, West Virginia, Kentucky, Tennessee, North Carolina, and Georgia. Its other names are prickly pine, hickory pine, and southern mountain pine. It supplies timber in all parts of its range, but, except in very restricted localities, it is not abundant. The lumber in the market is seldom distinguished from other pines, but some of the Tennessee mills sell it separately to local customers. The wood is medium light, rather strong (about like Pinus rigida, or pitch pine, which it resembles in other respects), is less stiff than white pine, and is resinous. The thick sapwood is nearly white, the heartwood brown. It is not a durable timber in contact with the ground. Its fuel value is low. Its needles grow in clusters of two, and are generally less than two inches long. The cones which are in clusters of from three to eight, and from two to three and a half inches long, are armed with stout, curved hooks. The cones shed their seeds irregularly during two or three years, and sometimes hang on the trees for twenty years. In open ground this pine occasionally produces fertile seeds when only a few feet high. Its forest form and open-ground form are quite different. In thick woods the tree is tall, with good bole, but in open ground it is only twenty or thirty feet high, and is covered with limbs almost to the ground.