Читать книгу American Forest Trees - Henry H. Gibson - Страница 41

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In New York the tree is called yellow spruce, while in foreign literature it is known as North American red spruce. The tree is sometimes difficult to distinguish from black spruce (Picea nigra), the main points of difference in the appearance of the two trees being the size and shape of the cones and of the staminate blossoms. The cones of red spruce are larger than those of black, and they mature and drop from the branches during their first winter, while those of the latter named species frequently remain on the trees for several seasons. Certain eminent botanists incline to the belief that the two are different varieties of one species, inasmuch as even the timber of red spruce bears a close resemblance to that of the black spruce. Other botanists dispute this theory, saying that the trees are entirely different in appearance; that the red spruce is a light olive-green, while black spruce is inclined to a darker olive with perhaps a purplish tinge, so that when seen together they have no resemblance in point of color. They further say that the cones are not only different in size but that the scales are quite unlike in texture, those of black spruce being much thinner and more brittle. The same authorities maintain that the tiny twigs of red spruce are more conspicuous on account of their reddish tinge.

Generally speaking the principal spruce growth of northern New England and New York is black spruce, although interspersed with it in some localities is a considerable quantity of red spruce. On the contrary the chief stand of spruce in West Virginia, Virginia, western North Carolina, and eastern Tennessee and the other high altitudes over the South Carolina line, is largely red spruce. This botanical analysis of the two species of wood is based entirely on the authority of botanists, but from the viewpoint of the average lumberman there is absolutely no difference between red and black spruce and none in the physics of the two woods except that which rises from varying conditions of growth as soil, rainfall, altitude or latitude, or general environment. The larger spruce of West Virginia and the mountain region farther south, has certain qualities of strength and texture, combined with a large percentage of clear lumber that is not approximated by the spruce of New England and the British maritime provinces. In shape the tree is pyramidal, with spreading branches. It reaches a height of from seventy to a hundred feet. Its bark is reddish brown, slightly scaly. The twigs are light colored when young and are covered with tiny hairs. The leaves are thickly clustered along the branches, and are simple and slender, pointed at the apex. They become lustrous at maturity. The staminate flowers are oval, bright red in color; the pistillate ones are oblong, with thin rounded scales. The fruit of the red spruce is a cone, from one to two and a half inches in length; it is green when young, turning dark with age, and falling from the branches when the scales open. The seeds are dark brown, and winged.

Formerly spruce was little thought of for lumber and manufacturing purposes in this country, though some use was made of it from the earliest settlements in the regions where it grew. White pine could generally be had where spruce was abundant, and the former wood was preferred. As pine became scarce, spruce was worked in for a number of purposes. The tree’s form is all that a sawmill man could desire. The trunk has more knots than white pine, for the reason that limbs are a longer time in dying and in dropping off; but knots are small and generally sound. By careful culling, a moderate amount of clear lumber may be obtained. The wood is light, soft, narrow-ringed, strong in proportion to its weight, elastic, and its color is pale with a slight tinge of red, the sapwood whiter and usually about two inches thick. The contrast between heart and sapwood is not strong. The medullary rays are numerous, but small and obscure. The summerwood is thin and not conspicuous. It is the wood’s red tinge which gives the tree its commercial name.

It is believed that the yearly cut of red spruce in the United States for lumber is about 500,000,000 feet, one-half of which comes from West Virginia and southward, where this species reaches its highest development; and the pulpwood cut in the same region is about one-tenth as much in quantity. The long fiber and white color of spruce make it one of the most satisfactory woods for pulp in this country. Red spruce is only one of several species of spruce which contribute to the supply. The total output of spruce pulpwood in the United States yearly is equivalent to about 1,000,000,000 feet of lumber.

Red spruce lumber has a long list of uses. Much flooring is made of it, and it wears well, but not as well as hard pine from the South. It is more used for shipping boxes in the northeastern part of the United States than any other wood, except white pine. Its good stenciling qualities recommend it. Manufacturers of sash, doors, and blinds find it excellent material, combining lightness, strength, and small tendency to warp, shrink, or swell. Coopers make buckets, tubs, kegs, and churns of it; manufacturers of refrigerators use it for doors and frames; and makers of furniture use it for many interior parts of bureaus, tables, and sideboards. Textile mills use spruce clothboards as center pieces round which to wind fabrics; and a further use in mills is for bobbins. It has many places in boat building, notably as spars and yards; and for window and door frames.

The makers of piano frames employ red spruce for certain parts; but as material for musical instruments its most important use is as sounding boards. All the commercial spruces are so used. Wood for this purpose must be free from defects of all kinds, and of straight and even grain. The sounding board’s value lies in its ability to vibrate in unison with the strings of the instrument. Spruce has no superior for that place.

Red spruce bears abundance of seeds, the best on the highest branches. The seeds are winged, and the wind scatters them. They germinate best on humus. In spruce forests, clumps of seedlings are often seen where logs have decayed and fallen to dust. Seedlings do not thrive on mineral soil, and for that reason red spruce makes a poor showing where fires have burned. It does not spread vigorously in old fields as white pine does. It must have forest conditions or it will do little good. For that reason it does not promise great things for the future. It grows very slowly, and land owners prefer white pine, where that species will grow. If spruce is to be planted, most persons prefer Norway spruce (Picea excelsa) of Europe. It grows faster than native spruces. It is the spruce usually seen in door yards and parks.

Black Spruce (Picea mariana) grows much farther north than red spruce, but the two species mingle in a region of 100,000 square miles or more northward of Pennsylvania and in New England and southern and eastern Canada. Black spruce grows from Labrador to the valley of the Mackenzie river, almost to the arctic circle. It is found as far south as the Lake States where it constitutes the principal spruce of commerce. In some of the swamps of northern Minnesota and in the neighboring parts of Canada it is little more than a shrub, and trees three or four feet high bear cones. On better land in that region the tree is large enough for sawlogs. It passes under several names, among which are double spruce, blue spruce, white spruce, and water spruce. The common name black spruce probably refers to the general appearance of the crown. The small cones (the smallest of the spruces) adhere to the branches many years, and give a ragged, black appearance to the tree when seen from a distance. The wood is as white as other spruces. Trees vary greatly in size. The best are 100 feet high and two and a half feet in diameter; but the average size is about thirty feet high and twelve inches in diameter. That size is not attractive to lumbermen; but cutters of pulpwood find it valuable and convenient, and much of it is manufactured into paper. The wood weighs 28.57 pounds per cubic foot, and is moderately strong, and high in elasticity. It is pale yellow-white with thin sapwood. In Manitoba, lumber is sawed from black spruce, and it is cut also in the Lake States, but it is preferred for pulp. It gives excellent service as canoe paddles. Spruce chewing gum is made of resinous exudations from this tree, and is an article of considerable importance. Spruce beer is another by-product which has long been manufactured in New England and the eastern Canadian provinces. It was made in Newfoundland three hundred years ago and has been bought and sold in the markets of that region ever since. Fishing vessels carry supplies of the beverage on long voyages as a preventive of scurvy. The beer is made by boiling leaves and twigs, and adding molasses to the concoction which is allowed to pass through mild fermentation. Foresters will probably never pay much attention to black spruce because other species promise more profit. It is little planted for ornamental purposes, as it does not grow rapidly, is of poor form, and the accumulation of dead cones on the branches gives it a poor appearance. Besides, planted trees do not live long.

White Spruce (Picea canadensis) is of more importance in Canada than in the United States, because more abundant. It is one of the most plentiful timber trees of Alaska, and it is found west to Bering strait and north of the arctic circle. It is said to approach within twenty miles of the Arctic ocean. Its eastern limit is in Labrador, its southern in the northern tier of states from Maine to Idaho. A little of this species is cut for lumber in northern New England and in upper Michigan, and westward, just south of the Canadian line. The light blue-green foliage gives the tree its name. It is known by other names as well, single spruce, bog spruce, skunk spruce, cat spruce, double spruce, and pine. Some of its names are due to the odor of its foliage. The largest trees are 100 feet high and three in diameter, but most are smaller. Having a range so extensive, and in climates and situations so different, the tree naturally varies greatly in size and form. The wood of well-developed trees is white and handsome, the thin, pencil-like bands of summerwood having a slightly darker tone than the springwood. The two parts of the annual ring possess different degrees of hardness. The springwood is softer than the summerwood. The medullary rays are numerous, and the surface of quarter-sawed lumber has a silvery appearance, due to the exposed flat surfaces of the rays. In the markets, no distinction is made between white spruce lumber, and that cut from other species. The uses of the different species are much the same. As a pulpwood, white spruce is in demand wherever it is available. The largest output in the United States comes from northern New England. The tree is often planted for ornamental purposes in Europe and in northern states. When grown in the open, the crown is pyramidal, like that of balsam fir. It does not thrive where summers are warm and dry.