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 associated 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 quantity 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 quantities 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 competitors 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 quantity 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 identity 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 canal 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 shore 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, furnishing shelter for more valuable species which come later.
Blue Birch (Betula cÆrulea) 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 lustrous. 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.
Paper birch branch
