American Forest Trees Part 46

[8] The eastern species, which do not extend west of the continental divide, are, Sweet Birch (_Betula lenta_), Yellow Birch (_Betula lutea_), River Birch (_Betula nigra_), Paper Birch (_Betula papyrifera_), White Birch (_Betula populifolia_) and Blue Birch (_Betula caerulea_). The western birches, none of which are known to extend much east of the continental divide, are: Western Birch (_Betula occidentalis_), Mountain Birch (_Betula fontinalis_), White Alaska Birch (_Betula alaskana_), and Kenai Birch (_Betula kenaica_). The last two occur in Alaska, but not in United States proper.

It attains a height of seventy or eighty feet, and a diameter of two or three. It prefers deep, moist, rich soil, but will grow in comparatively dry, rocky ground. Its seeds are produced in large numbers and are scattered by the wind a hundred feet or more from the parent tree. They lack the wing power and the buoyancy of the seeds of some of the other birches, but they manage to get themselves sown in sufficient numbers, and their powers of germination are good.

The young seedling comes into existence with smooth bark, but it does not keep it through life. As age increases, the bark becomes rough and black. It is not shed in papery rolls and flakes as is the bark of river birch, yellow birch, and paper birch, with which it is a.s.sociated in some parts of its range. It is generally an easy tree to identify and the black, rough bark is generally a sufficient guide.

The sweet birch is tapped like sugar maple, but not for the same purpose or to the same extent--only an occasional tree. Immense quant.i.ties of sap will flow from it during the two or three weeks when the buds are swelling in the spring. It is said that as much as two tons has been known to flow from a medium sized birch in a single season. The sap is made into a beer which has some commercial value, but is chiefly used locally. One of the ways of making it, employed by farmers and woodsmen, is to jug the sap, put in a handful of sh.e.l.led corn, and let fermentation do the rest.

A substance known in commerce as oil of wintergreen is procured almost exclusively from this birch, though occasionally it is made from the small wintergreen plant (_Gaultheria proc.u.mbens_). The product is manufactured in very crude stills made by mountaineers in Pennsylvania and southward along the mountains where sweet birch is abundant.

Frequently the woodsman's whole family go into the business, chopping down birch bushes and hacking them with hatchets into chips of the desired sizes. The oil is extracted from the hogged ma.s.s by a steaming and roasting process. It is sold by the quart to country storekeepers who s.h.i.+p it to wholesale druggists where it is refined and used to flavor candy, medicine, and drugs. The woodsman who manufactures the oil prefers young birches from half an inch to two or three inches in diameter, and he usually procures them in old logging grounds where seedlings have sprung up. It is said that on an average one hundred small birch trees are destroyed for each quart of oil that goes to market. It is a process wasteful in the extreme.

In the open ground, sweet birch develops a full crown, short trunk, abundance of limbs, with numerous slender, graceful twigs and small branches. Its leaves form a dense ma.s.s, and they are so free from attacks by insects and worms that diseased foliage is unusual. That cannot be said, however, of the trunk. It is not particularly liable to disease, but many old trees show the results of decay. It is of slow growth, and a small tree may be much older than its size indicates. The sapwood is generally thick, heartwood forms slowly, and the contrast in color between sap and heart is strong.

The wood of sweet birch had few uses in early times, except fuel. The pioneer sawmill had little to do with it. Lumber was hard to saw and was seasoned with difficulty. Its tendency to warp was too great a tax on the lumberman's patience and ingenuity. The only way he could hold it straight was to cob a few layers in the bottom of a pile, and stack thousands of feet of other lumber on top, and leave it a year or two.

That was generally too much trouble, particularly when the wood had slow sale, and the price was low. Birch reached market in large quant.i.ties only when modern mills and improved drykilns came into existence.

The wood is heavy, strong, hard, in color dark brown tinged with red.

The light brown or yellow sapwood generally makes up seventy or eighty annual rings. The difference between springwood and that of the later season is not clearly marked, and consequently the rings are often indistinct. The wood is very porous, and the pores are diffused through all parts of the ring. They are too small to be seen with the naked eye, except under the most favorable conditions. The medullary rays are numerous but so small that they appear on the quartered wood merely as a gloss, which, however, gives the surface a rich appearance.

Forms known as curly and wavy birch are highly esteemed. They are accidents of growth, well developed in birch, and occurring in several other woods. Difficulties are encountered in a.s.signing sweet birch its individual place in the industrial world. As a tree it is well known, but that is not the case when its lumber goes to market. The sweet birch log goes into the sawmill, but when the lumber goes out at the other end of the mill, it is often simply birch having lost the adjective "sweet"

somewhere in the operation. The reason is that sweet birch and yellow birch, quite distinct in the forest, are often mixed and become one, to all intents and purposes, when they reach the market. That is not always the case, but it frequently is. Something depends on the region. The yellow birch's range is more extensive, and in areas where it is abundant, and sweet birch is not, it prevails in the lumber markets. But south and southeast of the great lakes, as well as in the northeastern part of the country, the two species mingle, and they are apt to go to market simply as birch. The woods may be distinguished by a microscopic examination, but the ordinary observer would make many mistakes if he attempted to tell one from the other in the lumber yard.

The two woods are different in several physical properties. Both are heavy, but sweet birch weighs 47.47 pounds per cubic foot, while yellow birch weighs only 40.84 pounds, according to tests averaged by Sargent.

Yellow birch rates a little above the other in breaking strength. Both are very stiff, but yellow birch rates superior. In most respects the two woods are put to similar uses--flooring, interior finish, furniture--but for some purposes sweet birch is preferred. It is subst.i.tuted oftener for cherry and mahogany, and for that reason is known as cherry birch or mahogany birch. Its color makes the subst.i.tution easy, and the appearance of the grain, with a little doctoring with stains and fillers, helps in the deception. The buyer may be deceived as to the exact kind of wood he is getting, but he is not cheated in the quality. Birch is subst.i.tuted where strength is required, as in the rails of beds, the frames of sofas, davenports, large chairs, and certain parts of large musical instruments. It is much stronger, and fully as hard as cherry or mahogany, and as its appearance is so much like them, the article is actually better on account of the subst.i.tution. Sweet birch is largely employed for various parts of vehicle manufacture, particularly for wagon hubs and frames of automobiles. It is also much used in the manufacture of sleds, boats, and handles.

The demand is heavy and the supply is diminis.h.i.+ng. The tree is of such slow growth that few timber owners will be inclined to wait for a second crop, after the old trees have been cut, since 150 years are necessary under forest conditions to produce a merchantable tree.

SONORA IRONWOOD (_Olneya tesota_) is a desert tree, and the only representative of the genus. It takes its name from the Mexican state where it is most abundant and where it was discovered in 1852.

It grows in southern California and Arizona, and there it thrives in gulches and depressions in the desert, frequently a.s.sociated with mesquite. It is so heavy that perfectly dry wood will sink in water.

The heartwood is deep chocolate-brown, mottled with red, the thin sapwood is lemon-yellow. Its hardness renders it difficult to work, and it can scarcely be split. The wood is made into canes and other small articles of great beauty. It is not abundant, and the small supply is remote from manufacturing centers; otherwise it would be more valuable. It is excellent fuel, but it is burned chiefly by stockmen and miners in their camps. The largest trees are thirty feet high and eighteen inches in diameter. It is an evergreen, and its pea-like flowers brighten many a remote desert place.

WILD TAMARIND (_Lysiloma latisiliqua_) is forty or fifty feet high, two or three in diameter, grows in southern Florida, and has double-compound leaves, four or five inches long. The fruit is a pod one inch wide and five or less in length. The wood weighs forty pounds to the cubic foot, is neither strong nor tough, very low in elasticity, is rich dark brown tinged with red, the sapwood white.

It has been reported for boatbuilding, and claims have been made that it is equal to mahogany for that purpose, but the claim is of doubtful validity, in view of the rather poor showing it makes in several physical properties, though it takes good polish.

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YELLOW BIRCH

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YELLOW BIRCH

(_Betula Lutea_)

There is little likelihood of mistaking the yellow birch for any other as it stands in the woods. Its points of individuality may be discovered on slight acquaintance, and there is little need of studying leaves, flowers, and fruit to find ways of distinguis.h.i.+ng this birch from other members of the family. Its tattered, yellow and gray bark fixes it in the memory of all who have seen it a few times. Two other eastern birches have tattered, curling bark also, but they do not look like this. They are the paper birch and the river birch. The former is too white to be mistaken for yellow birch, and the river birch is too much the color of bronze or copper. Yellow birch is named from the color of its bark, the part which shows when the outer layers break and roll back, disclosing the fresh, smooth, satiny layers below. Sometimes the tree is called silver birch, gray birch, or swamp birch.

Its geographic range is bounded by a line drawn from Newfoundland to northern Minnesota, southward through the Lake States, and along the Atlantic coast to Delaware. It follows the Appalachian ranges of mountains to eastern Tennessee and western North Carolina. Generally the tree is small near the southern limit of its range. The best grows in Michigan and Wisconsin, but it is of considerable importance in Minnesota.

Few trees are better equipped than yellow birch to perpetuate their species. It is an abundant seeder, and the seeds are light, winged, and they are scattered by wind over long distances. Sometimes they are carried miles. Of course, most of them fall in unfavorable places, and either do not germinate or perish soon after; but they are not particularly choice in situations, and will grow on bare mineral soil, even in old fields, where they are flooded with suns.h.i.+ne, or they will grow in deep shade where a beam of sunlight seldom touches them. They often germinate without touching mineral soil, and take root quickly and grow vigorously.

It is not unusual in the northern part of the tree's range, and on high mountains farther south, to see yellow birches standing on high, spreading roots, two, three, or four feet above the ground. That peculiar att.i.tude is brought about by the manner in which the seed begins to grow. It falls on moss which occupies the top of a log or a stump. The moss in the deep shade retains much moisture, and the seed germinates, grows, sends roots down the sides of the log or the stump until they strike mineral soil, and become firmly fixed. In course of time the log or stump decays, and the spreading roots continue to sustain the trunk, high above the ground. This att.i.tude of the yellow birch tree is very common in damp woods. Occasionally the seed finds lodgment in the moss on top of a large rock. The roots descend the sides until they reach the ground, and as the rock does not decay, the tree grows to maturity on the rock. The most favorable seed bed for this species is a ma.s.s of rotten wood where a log has decayed and fallen to pieces. Frequently such a plot is covered with yellow birch seedlings.

They have the s.p.a.ce all to themselves, because the seeds of few trees or plants will grow in rotten wood, unmixed with mineral soil.

The trunk of yellow birch averages a little smaller than that of sweet birch, but may equal it in some instances. Trees reach a height of 100 feet and a diameter of three or four, but a more common size, even in the regions of best development, is a height of sixty or seventy feet, and a diameter of two or less.

Yellow birch was a long time coming into use. One of the first things learned about it by early settlers in the region where it was abundant, was that it decays quickly in situations alternately wet and dry. That prejudiced the woodsmen against it, and they were not disposed to give it a fair trial, as long as there was plenty of other timber. All birches are subject to quick decay, if conditions are right to produce it. Yellow birch in the woods sometimes dies standing, and when that happens, the wood falls to pieces so quickly that the bark may remain standing with very little inside of it except powder of decayed wood.

This tree is seldom mentioned in early accounts of lumber operations, and practically never with a good word. Operators generally left it standing when they cut the timber which grew with it.

Yellow birch is heavy, very strong, hard, light brown tinged with red, with thin, nearly white sapwood. The color of the heartwood varies considerably. The pores are very numerous, rather small, and are scattered through the wood with little tendency to run in bands or groups. The springwood blends gradually with the summerwood in a way to make the boundaries of the annual rings somewhat indistinct. Medullary rays are numerous, but very thin and obscure. Quarter-sawing adds little or nothing to the appearance of the wood. It has poor figure, except an occasional tree with wavy or curly grain, or with burls.

The wood may be readily stained. The pores hold the coloring matter applied, and by varying the application, the appearance of the surface can be varied. The colors of mahogany and of cherry are easily imparted, and yellow birch often imitates those woods.

Vehicle makers choose this wood for its strength and elasticity. In the North it is manufactured into frames for cutters and sleighs of all kinds. It is a compet.i.tor of sugar maple for that purpose. Hubs are made of it for horse-drawn vehicles, and its hardness gives long wear where the spokes are inserted. That is one of the first points of failure when a soft, inferior wood is used for hubs. The spokes work loose.

Manufacturers of automobiles have tried out yellow birch as material for frames; it has stood the test, and is much used in compet.i.tion with other woods. The amount demanded for that purpose is not necessarily large, but it must be the best wood that can be had.

This material reaches the markets in all grades. Large amounts are used for packing boxes, crates, and s.h.i.+pping containers. Low grades answer for these purposes, leaving the better sorts for the more exacting industries. The logs are cut in rotary veneer for baskets, and for ply work. Some of the veneer in three-ply is worked into commodities of high cla.s.s, such as seats and backs of theater chairs.

Birch flooring competes closely with maple for popular favor. It may lack something of maple's whiteness, but it takes no second place in hardness, smoothness, and wearing qualities. It is made into parquet flooring as well as the ordinary tongued and grooved article. As such, the sap matches the light colored woods, and the heart the dark.

It goes into all kinds of interior house finish, from floor to ceiling, and the finest grades are often devoted to stair work. Door and window frames are made of it in large quant.i.ties, but it is not suited to outside work exposed to weather, because of its tendencies to decay. It is much employed as door material. Furniture demands the same cla.s.s of wood. Medium priced articles may be of solid birch, but the best commodities are made of veneers laid upon other woods. Figured birch is a favorite material for that cla.s.s of work.

The more common commodities manufactured of this wood can be listed only by groups, because of their great number. Novelties const.i.tute a large cla.s.s. One of the earliest demands was from the manufacturers of pill boxes, such as apothecaries use. That was before anyone had tried to sell yellow birch in the general market, and the demand came princ.i.p.ally from New England and New York. Another early demand came from coopers who found that barrel hoops of yellow birch were highly satisfactory for certain kinds of vessels. Fish kits were among the first to appear in birch hoops. Small saplings were used, not over two inches in diameter.

They are large enough to make two hoops by splitting. The bark was left on, and the ident.i.ty of the wood was never in doubt, because when the sapling is of that size, the bark is a fine yellow. It has not yet commenced to crack open and roll up, as it does later. Millions of birch hoops are still produced yearly in the United States, but all of them are not of this species. The hoop business has existed much more than a century, and millions of young birches have been cut every year to meet the demand.

Birch broom handles have been a commodity since the first lathe went to work on that product. They are made of all the commercial birches, but yellow birch contributes a large part. Other handles are manufactured of it also, such as are fitted to hand saws, planes, drawing knives, chisels, and augers.

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RIVER BIRCH

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RIVER BIRCH

(_Betula Nigra_)