American Forest Trees Part 47

This tree is known as red birch, river birch, water birch, blue birch, black birch, and simply as birch. The name red birch refers to the color of the bark which is exposed to view in the process of exfoliation. The trunk is constantly getting rid of its outer bark, and in doing so, the exterior layers are rolled back, hang a while, and are gradually whipped off by the wind. The new bark which is exposed to view when the old is rolled back is reddish. Its color varies considerably, sometimes suggesting the tint of old bra.s.s, again it is brown, but people in widely separated regions have seen fit to call the tree red birch because of the color of its bark. The name black birch is not appropriate, though the old bark near the base of large trunks may suggest it. No reason can be a.s.signed for calling it blue birch, unless the foliage in early summer may warrant such a term. River birch and water birch are more appropriate, as these names indicate the situations where the species grows. It clings to water courses almost as closely as sycamore. A favorite att.i.tude of the tree is to lean over a river or pond, with the long, graceful limbs almost touching the water.

Nature seems to recognize the tree's habit of hanging over muddy banks, and has prepared it for that manner of life. Seeds are ripe early in summer when the rivers are falling. They are scattered by myriads on the muddy sh.o.r.es and upon the water. Those which fall in the mud find at once a suitable place for germination, and those whose fortune it is to drop in the water float away with the current or they are driven by the wind until they lodge along the sh.o.r.es, and the receding water leaves them in a few days, and they spring up quickly. Before the autumn or early winter high water comes, they are well rooted in the mud and sand, ready to put up a fight for their lives.

The provision is a wise one. If the seeds matured in the fall, when water is low, they would be strewn along the low sh.o.r.es, and before they could take root and establish themselves, the high water and the ice of winter would destroy them. The seeds need mud to give them a start in life, and they need that start early in summer.

The range of river birch is less extensive than that of the other important eastern birches, yet it is by no means limited. Its eastern boundary is in Ma.s.sachusetts, its western in Minnesota, and it adheres fairly well to a line drawn between the two states. Its range extends 200 miles west of the Mississippi and covers most of the southern states. It is found in an area of nearly 1,000,000 square miles, but is scarce in most of it. In certain restricted localities it is fairly abundant, but there are thousands of square miles in the limits of its range which have not a single tree. Its greatest development is in the south Atlantic states, and in the lower Mississippi basin.

Trees at their best are from eighty to ninety feet high and from two to four in diameter, but most trunks are less than two feet in diameter.

The tree frequently forks fifteen or twenty feet from the ground, or occasionally sends up several stems from the ground. Forms of that kind are practically useless for lumber.

The wood is among the lightest of the birches and weighs 35.91 pounds per cubic foot. It is rather hard, medium strong, the heartwood light brown in color, with thick, pale sapwood. It rates below sweet and yellow birch in stiffness, is very porous, but the pores are quite small, and can scarcely be seen without a magnifying gla.s.s. They are diffused throughout the entire annual ring. There is no marked difference in the appearance of the springwood and that of the late season. The medullary rays are very small and have little effect on the appearance of the wood, no matter in what way the sawing is done.

The wood is apt to contain pith flecks and streaks. These are small, brown spots or lines scattered at random through the wood. They are a blemish which is not easily covered up if the wood is to be polished; but they are small and may not be objectionable. The flecks are caused by insects which, early in the season, bore through the bark into the cambium layer (the newly-formed wood), where eggs are deposited. The young insect cuts a tunnel up or down along the cambium layer, an inch or less in length and a sixteenth of an inch wide. This gallery subsequently fills with brown deposits which remain permanently in the wood. Sometimes these deposits are sufficiently hard to turn the edge of tools.

River birch is widely used but in small amounts. It may properly be described as a neighborhood wood--that is, wherever it grows in considerable quant.i.ty it is put to use, but nearly always in a local way. For example, in Louisiana, where it is as abundant as in any other state, it is a favorite material for ox yokes, and no report from that state has been made of its employment for any other purpose. The reason given for its extensive use for ox yokes there is that it is very strong for its weight, and that it resists decay. The yokes there are usually left out of doors when not in use, and the dampness and hot weather cause rapid decay of most woods. The birches are usually listed as quick-decaying woods, but the verdict from Louisiana seems to be that river birch is an exception.

Plain furniture is made of it, and the manufacturers of woodenware find it suitable for most of their commodities. It is sometimes listed as wooden shoe material, but no particular instance has been reported where it has been so used in this country. In Maryland some of the manufacturers of peach baskets make bands or hoops of it, and p.r.o.nounce it as satisfactory for that purpose as elm.

The supply is not in much danger of exhaustion. The species is equipped to take care of itself, occupying as it does, ground not in demand for farming purposes. When a tree once gets a start it has a chance to escape the ax until large enough for use.

WHITE ALASKA BIRCH (_Betula alaskana_) is usually called simply white birch where it grows. It is not exclusively an Alaska species though that is the only place where it touches the territory of the United States. It is supposed by some to be closely related to the white birches of northern Asia, but the relations.h.i.+p, if it exists, has not been established. In Alaska it grows as far north as any timber extends.

It was first discovered and reported in 1858 on the Saskatchewan river, east of the Rocky Mountains, and its range is now known to extend down the valley of the Mackenzie river toward the Arctic ocean to a point more than 100 miles north of the Arctic circle. It is common in many parts of Alaska both along the coast and in the interior. In some portions of that territory it is an important source of fuel. Trees are from twenty-five to sixty feet high, and from six to eighteen inches in diameter. The bark is thin and often nearly white, separating into thin scales. The tree bears typical birch cones, but larger than those of some of the other species. No tests of the wood's physical properties have been made, but it looks like the wood of paper birch, and will probably attain to considerable importance in the future, since it grows over a large area, and in many parts is abundant. There remain many things for both botanists and wood-users to investigate concerning this tree which has a range of more than half a million square miles.

WESTERN BIRCH (_Betula occidentalis_) is believed to be the largest birch in the world, and yet it is not of much commercial importance in the United States, because of scarcity, occurring only in northwestern Was.h.i.+ngton and in the adjacent parts of British Columbia, as far as its range has been determined. It resembles paper birch, and has often been supposed to be that tree. The people in the restricted region where it grows speak of it simply as birch. The largest trees are 100 feet high and four feet in diameter, clear of limbs forty or fifty feet. A height of seventy feet and a diameter of two are common. The general color of the trunk is orange-brown, the new bark, exposed by exfoliation, is yellow. The tree prefers the border of streams and the sh.o.r.es of lakes.

Though it is the largest of the birches, its seeds are among the smallest. They are provided with two wings and are good flyers.

Manufacturers of flooring and interior finish in Was.h.i.+ngton reported the use of 315,000 feet of this birch in 1911. That was the only use found for it in the only state where it grows. Information is meager as to the probable quant.i.ty of this birch available. It has been reported in Idaho, but exact information on the subject is lacking.

MOUNTAIN BIRCH (_Betula fonta.n.a.lis_) is a minor species concerning which there has been much contention among botanists. It has finally been called mountain birch because it grows on mountains, as high as 10,000 feet among the Sierra Nevadas in California. It has many local names for a tree so small as to be almost a shrub throughout most of its range: Black birch, sweet birch, cherry birch, water birch, and canyon birch. Its bark is of the color of old copper; wood is light yellowish-brown, with thick white sapwood; trunks seldom exceed ten inches in diameter and thirty feet high; range extends from northern British Columbia to California, and along the Rocky Mountains to Colorado and possibly further south. The uses of the wood are few.

[Ill.u.s.tration]

PAPER BIRCH

[Ill.u.s.tration: PAPER BIRCH]

PAPER BIRCH

(_Betula Papyrifera_)

This tree is called paper birch because the bark parts in thin sheets like paper. It is known as canoe birch from the fact that Indians and early white explorers and travelers constructed canoes of the bark. The name silver birch is an allusion to the color of the bark; and big white birch is the name used when the purpose is to distinguish it from the white birch with which it is a.s.sociated in the northeastern part of its range. It grows as far north as Arctic British America, east to Labrador, south to Michigan and Pennsylvania, and west nearly or quite to the base of the Rocky Mountains. This indicated area exceeds 1,000,000 square miles. The quant.i.ty of birch of this species in the forests is unknown, but it runs into billions of feet, probably exceeding any other single species of birch. The tree sometimes grows dispersed through forests of other woods, sometimes in nearly pure stands. Persons well acquainted with the species have expressed the opinion that paper birch exists in larger quant.i.ties now than at the time when the country was first explored by white men. That can be said of few other species; but probably holds true of lodgepole pine in the West, loblolly pine in the Southeast, and mesquite in the Southwest.

Each of these species took advantage of man's presence and influence to extend its range. Cattle spread the mesquite; the lodgepole pine came up in fire-burned tracts; loblolly pine spread into abandoned fields; and paper birch profited by fires which destroyed large tracts of timber.

The seeds are light, are furnished with wings which sail them long distances through the air, and they are quickly scattered over the burned areas where they spring up. In the contest, they are compet.i.tors of aspen. Birch often captures the ground, but does not always do it.

Some of the largest stands in the Northeast occupy tracts bared by fire half a century or more ago. When paper birch does not find open tracts, it contents itself with sharing ground with other species. That was the usual manner of its growth in the original forests; but it has been quick to seize opportunities to take full possession.

It does not like shade and, if crowded, one of the first things it does is to rid its lower trunk of all branches. Only limbs remain which are at the top where they receive plenty of light. Therefore, forest-grown paper birches have long, clean trunks, though they are not always straight. The largest trees are seventy feet high and three in diameter, but those fifty feet in height and eighteen inches in diameter are above rather than under the average.

The bark of paper birch has played an important part in American history, story, and poetry. It was the canoe material, the roof, and the utensil in its region. The Indians had brought the art of canoe making to perfection before white men went among them. The bark peels from the trunks in large pieces, and may be separated into thin sheets, which are very tough, strong, and durable. The Indians sewed pieces of bark together, using the long, slender roots of tamarack for thread. The bark was stretched and tied over a frame, the shape of the canoe, and made of northern white cedar, or some other light wood. Holes in the bark, and the partings at the seams, were stopped with resin from balsam fir, wax from balm of Gilead, or resin from pine. The forest supplied all the material needed by the Indian, and a canoe thus made, and large enough to carry 800 or 1,000 pounds, weighed no more than fifty pounds. Frail as it seemed, it was good for long service on rivers and lakes, and could weather storms of no small severity.

White men adopted the bark canoes at once, and learned from Indians how to make them. The daring explorers and venturesome fur traders who threaded every river and navigated every important lake of British America, found the birch canoe equal to every requirement, even to attacking whales in the tidewater of the Arctic ocean. The bark from this birch was used for tents and the roofs of cabins; vessels in which to store or carry food were made of it, as well as beds on which to sleep, and wrapping material for bundles. These uses have now practically ceased; but as sport, recreation, and for the novelty, articles, from canoes to visiting cards, are still made of the bark.

The wood of paper birch is valuable for certain purposes. The trees are largely white sapwood, which is without figure. It is as plain a wood as grows in the forest, but it may be stained. That, however, is seldom done. The heartwood is dark or red, and is made into brush backs and parquet flooring, but the hearts are small, and no large quant.i.ty of that wood is used. The largest use of paper birch is for spools, the common kind for thread. Some of larger size are made for use in mills.

The sapwood only is accepted by makers of spools. The heart is cut out, and most of it is thrown away or burned under the boilers. The qualities of paper birch which appeal to spool makers are, white color, small liability to warp, and the ease with which it may be cut without dulling the tools. The logs are worked into bars of the various spool sizes, and are carefully seasoned. One of the problems that must be constantly solved is the prevention of sap stain while the bars are seasoning. The wood discolors quickly and deeply.

Tooth picks, shoe pegs, and shoe shanks are other important commodities manufactured from paper birch. It has not yet been satisfactorily converted into lumber, because it is more valuable for spools, tooth picks, pegs, and the like. This wood is frequently listed as a pulpwood, and it is quite generally believed that its use for that purpose is important. This is apparently an error, as the wood is not even mentioned in statistics of pulpwood output in this country.

Paper birch weighs 37.11 pounds per cubic foot, is strong, hard, tough; medullary rays are numerous but very small and obscure; wood is diffuse-porous, and earlywood blends gradually with latewood in the annual rings which are not very distinct.

This is one of the woods which does not threaten to become soon exhausted. A supply for half a century, at present rate of use, is in sight, if no more should grow; but in fifty years new forests, now young, will be large enough to use.

KENAI BIRCH (_Betula kenaica_) is an Alaska species concerning which comparatively little is known, except that its botanical ident.i.ty and something of its range have been established. Its small size, and the remote regions where it grows, do not necessarily indicate that it can never be important. Scarcity of other woods may give it a place which it does not now occupy. No reports on the properties of the wood have been made. The bark is deep brown in color. Trees are from twenty to thirty feet high and from twelve to eighteen inches in diameter. The trunks are very short. Cones are an inch or less in length and the double winged seeds are very small. The name applied to this species relates to the region where the best developed trees have been found. As far as known, the species is confined to the coast region of Alaska and to adjacent islands from the head of Lynn ca.n.a.l westward. It has been reported on Koyukuk river above the Arctic circle.

WHITE BIRCH (_Betula populifolia_) is known also as gray birch, old-field birch, poverty birch, poplar-leaved birch, and small white birch. It is chiefly confined to the northeastern part of the United States, but grows as far east as Nova Scotia, and west to the southern sh.o.r.e of Lake Ontario. It occurs on the Atlantic coast south to Delaware, and along mountain ranges to West Virginia. The names describe either the habits or the appearance of the tree. The bark is white, and is the most prominent feature of a thicket of these graceful but practically worthless little birches. It is called an old-field species because it quickly scatters its small, winged seeds over abandoned farmland and takes possession when it does not have to compete with stronger species. Poverty birch is an allusion, either to the poor ground it occupies or the unpromising nature of the tree itself. The resemblance of its leaves to those of cottonwood leads some people to prefer the name poplar-leaved birch.

The tree at its best is seldom more than forty feet high and eighteen inches in diameter. A height of twenty or thirty feet is the usual size. The stem is generally clothed with branches nearly to the ground. The wood is light, soft, not strong or durable, heart light brown, thick sap nearly white. The form and size of the trunk exclude it from sawmills, but it has some special uses: Spools, shoe pegs, and hoops. Its small size does not disqualify it for service along those lines. The tree springs up quickly, grows with fair rapidity, and dies young. It is cut for cordwood in New England and makes good fuel. It takes possession of areas bared by fire, and protects the ground, furnis.h.i.+ng shelter for more valuable species which come later.

BLUE BIRCH (_Betula caerulea_) is a small tree of which more information is to be desired. It is rarely more than thirty feet high with a diameter of eight or ten inches. Its leaves are long-pointed, its cones about an inch in length, the bark is thin, white tinged with rose, and is l.u.s.trous. Bark is not easily separated into layers, in that respect differing from the paper birch. The inner bark is of light orange color. It is probably put to no use, unless for fuel or as hoops. It is smallest of New England birches, and its range has not been fully determined, but it is known to grow in Maine and Vermont, and probably will be found in other parts of New England and in the adjacent regions of Canada. It has been compared with a European species of birch, the _Betula pendula_.

[Ill.u.s.tration]

RED ALDER

[Ill.u.s.tration: RED ALDER]

RED ALDER

(_Alnus Oregona_)

Many species of alder are found in various parts of the world, and on both sides of the equator, but chiefly in the northern hemisphere. Some of these are trees, others are shrubs. Six species belonging in the tree cla.s.s grow in the United States, besides others which remain shrubs.

Some trees are burdened with names, changing them with locality, but not so with alder. An adjective may accompany the name, as red, white, seaside, or mountain, to describe it, but it is always alder, no matter where it grows. The different species cover much of the United States, and few large areas are found which have not one or more species. It grows from sea level up to 7,000 feet or more, but some species thrive at one elevation, and others above or below.

The alders are old inhabitants of the earth. They had a place in the Eocene and Miocene forests of the old world and new. It is not apparent that they have either gained or lost in extent of range during the hundreds of thousands of years which measure their tenancy on the earth.

They have not been aggressive in pus.h.i.+ng their way, nor have they shown a disposition to retire before the aggression of other trees. Some alders bear seeds equipped with wings for wind distribution, others produce wingless seeds which depend on water to bear them to suitable situations and plant them. Of course, the water-borne seeds are planted on muddy sh.o.r.es or on the banks of running streams, and the trees of those species are confined to such situations. The alders belong to the birch family.