Читать книгу American Forest Trees - Henry H. Gibson - Страница 43

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This is largest of the spruces. In height and in girth of trunk no other approaches it. The moist, warm climate of the north Pacific slope is its favorite home, though its range extends far northward along the islands and coast of Alaska. Toward the extreme limit of its habitat it loses its splendid form and size and degenerates into a sprawling shrub. The limit of the species southward lies in Mendocino county, California. Its range in a north and south direction is not less than 2,000 miles; but east and west the growth covers a mere ribbon facing the sea. It climbs some of the British Columbia mountains, 5,000 feet, but it prefers the low, wet valleys and flatlands, or the rainy and snowy slopes set to catch the sea winds. There it is at its best, and the largest trunks are 200 feet high, fifteen feet in diameter, and about 850 years old. All sizes less than this are found. It is not easy to name an average size when variation runs from giants to dwarfs; but in regions where this spruce is cut for lumber, the average height of mature trees is about 125 feet, with a diameter of four feet.

Tideland spruce is one of its names. That has reference to its habit of sticking close to the sea. Its other names are Menzies’ spruce, great tideland spruce, and western spruce. The last may be considered its trade name in lumber markets, for it is seldom called anything else when it is shipped east of the Rocky Mountains. The name is appropriate, except that other spruces grow in the West, and are equally entitled to the name. This applies particularly to Engelmann spruce of the northern Rocky Mountain region; but its lumber and that cut from Sitka spruce are not liable to be confused in the mind of anyone who is acquainted with the two woods. The name Sitka refers to the town of that name in Alaska.

The leaves of this species are usually less than one inch in length, and in color are light yellowish green. They stand out like bristles on all sides of the twigs. Cones are from two to four inches long, and hang by short stems, usually at the ends of twigs. They ripen the first year, release their seeds, which fly away on small but ample wings, and the cones drop during the fall and winter. Sitka spruce bark is generally less than half an inch in thickness. Trunks which grow in forests prune themselves well, and are usually clear of limbs from forty to eighty feet. The bases of trees which grow on wet land are much enlarged like cypress and tupelo, and lumbermen frequently cut above the swell, leaving from 1,000 to 5,000 feet or more of lumber in the stump. Sitka spruce’s characteristic root system is shallow; but on mountain sides where soil is dry, roots penetrate deep in search of moisture.

The wood of this spruce varies greatly in color, but it is usually a very pale brown, with the faintest tinge of red. It is a little heavier than white pine, considerably weaker, and with less elasticity. The size of the trunks, with their freedom from limbs, insures a high percentage of clear lumber when Sitka spruce is manufactured. The tree grows slowly, the annual rings are narrow, and the bands of summer growth are comparatively broad, to which fact the rather dark color of the wood of the spruce is due.

Sitka spruce is an important source of lumber. The total cut in Washington, Oregon, and California in 1910 was about 255,000,000 feet. It is below red spruce in quantity of sawmill cut, but above all other spruces in the United States. The people of the Pacific coast use much of it at home, but large quantities are shipped to markets in eastern states, and some to foreign countries. Nearly 4,000,000 feet were bought by Illinois manufacturers in 1909, in addition to what was used rough in the state. The commodities manufactured of this spruce in Illinois indicate with a fair degree of accuracy the uses made of the wood in most parts of the United States east of the Rocky Mountains and north of the Ohio river and the Potomac. Among articles so manufactured in Illinois are playground apparatus, porch and stair balusters, doors, blinds, sash and frames, poultry brooders, sounding boards for pianos and other musical instruments, parts of mandolins and guitars, pipes for organs, cornice brackets, store and office fronts, decking and spars for boats, wagon beds and windmill wheel slats, refrigerators and cold storage rooms, ironing boards and other wooden ware.

Twenty times as much Sitka spruce is made into finished commodities in Washington as in Illinois. That is to be expected, since Washington is the home of the tree and the center of supply. A partial list of its uses in that state will show that the wood is liked at home. Douglas fir was the only wood bought in larger amounts by Washington manufacturers. They made 55,429,000 feet of it into boxes, and coopers employed 12,000,000 more. The next largest users were pulpmills, while 2,000,000 feet went into sounding boards, many of which were for shipment abroad. Other users were basket makers, and the manufacturers of furniture, fixtures, finish, caskets, veneer, trunks, pulleys, vehicles, boats, and patterns. Sitka spruce decays quickly when exposed to rain and weather.

Sitka spruce can be depended upon for the future. Though it grows slowly it may be expected to keep growing. Its range lies in regions generally too wet for woods to burn, and it will suffer less from forest fires than trees of inland regions. It is an abundant seeder, and its favorite seedbed is moss, muck, decayed wood, and wet ground litter of various kinds. For the first few years seedlings are sensitive to frost, but not in later life.

Sitka spruce is often planted as an ornamental tree in western Europe, and occasionally in the middle Atlantic states. The New England climate is too severe for it.

Engelmann Spruce (Picea engelmanni) was named for Dr. George Engelmann. It has other names. In Utah it is called balsam, white spruce in Oregon, Colorado, Utah, and Idaho, mountain spruce in Montana, Arizona spruce farther south, while in Idaho it is sometimes known as white pine. That name is misleading, for Idaho has a species of white pine (Pinus monticola). In eastern markets the wood is known as western spruce; but that, also, is indefinite, for Sitka spruce is also a western species and is found in the same markets as Engelmann spruce. This tree’s range extends from Yukon territory to Arizona, fully 3,000 miles. It is a mountain species and is found in elevated ranges. In the southern part of its habitat it ascends mountains to heights of nearly 12,000 feet. It grows in the Cascade mountain ranges in Washington and Oregon. The species’ best development occurs in British Columbia. At its best, trees are 150 feet high and four or five in diameter; but every size less than that occurs in different parts of its range, down to a height of two or three feet for fully matured trees. Such are found on lofty and sterile mountains where frost occurs practically every night in summer, and winter snows bury all objects for months at a time. Though the stunted spruce trees may be only two or three feet high, their branches spread many feet, and lie flat on the rocks. Though such situations are exceedingly unfavorable to tree growth, the stunted spruces survive sometimes for two hundred years, and during that long period may not grow a trunk above five inches in diameter and four feet high. The Engelmann spruce is naturally a long-lived tree, and large trunks are 500 or 600 years old; and trees ordinarily cut for lumber are 300 or 400 years old. When the tree is young, its form is symmetrical, the longest branches being near the ground, the shortest near the top; but in crowded stands the trunk finally clears itself. Engelmann spruce lumber is usually full of small knots, each of which represents a limb which was shaded off as the tree advanced in age. The wood is lighter than white pine, and is the lightest of the spruces, the weight being 21.49 pounds per cubic foot. It is not strong, and it rates low in elasticity. The wood is pale yellow, tinged with red. The thick sapwood is hardly distinguishable from the heart. It would be difficult to compile a list of this tree’s uses, because in markets it hardly ever carries its right name. It is used for fuel and charcoal in the region of its growth; also as farm timber, and as props and lagging in mines. When it goes to market, it is manufactured into doors, window frames, sash, interior finish for houses, and for purposes along with other spruces. Large quantities of this wood will be accessible when lumbermen penetrate remote mountain regions where it grows. It may be expected to increase in importance. It is occasionally planted in eastern states as an ornament.

Blue Spruce (Picea parryana) is found among mountains in Colorado, Utah, and Wyoming, from 6,500 to 10,000 feet above sea level. It attains a height of 150 feet and a diameter of three under favorable circumstances, but its usual size is little more than half of that. Its name is given on account of the color of its foliage, but it has other names, among them being Parry’s spruce, balsam, white spruce, silver spruce, Colorado blue spruce, and prickly spruce, the last name referring to the sharp-pointed leaves which are an inch or more in length. Cones are three inches long, and usually grow near the top of the tree. It is not unusual for blue spruce trees to divide near the ground in three or four branches. In its youth, particularly in open ground, blue spruce develops a conical crown. The wood is lighter than white pine, is soft, weak, and pale brown or nearly white in color. The sapwood is hardly distinguishable from the heart. This is a valuable tree for ornamental planting; but in later years it loses its lower limbs, and becomes less desirable.

Weeping Spruce (Picea breweriana) is of little commercial importance because of scarcity. It grows among the mountains of northern California and southern Oregon, at elevations of from 4,000 to 8,000 feet above sea level. The leaves are an inch or less in length, the cones from two to four inches long. They fall soon after they scatter their seeds. This tree is named on account of its drooping branchlets, some of which hang down eight feet. The wood seems not to have been investigated, but its color is pale yellowish to very light brown, and the annual rings are rather narrow. The tree ought to be valuable for ornamental planting, but nurseries have experienced much difficulty in making it grow. It grows on high and dry mountains where few ever see it, but refuses to become domesticated or to grace eastern parks.