RIVER BIRCH
(Betula Nigra)

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 brass, 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 assigned 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 attitude 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 shores 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 shores, 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 shores, 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 Massachusetts, 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 glass. 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 quantity 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 pronounce 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 relationship, 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 Washington 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 shores 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 Washington 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 quantity of this birch available. It has been reported in Idaho, but exact information on the subject is lacking.