TREES WE KNOW BY THEIR BARK Hunters and foresters who spend much of their time in the woods learn to know trees by name through long acquaintance. In the dead of winter, the framework of a tree may be enough to recognise it by. Where trees are crowded, this sign is not to be depended upon. The bark is often a guide to the tree's name. The forester will tell you that the bud is the sur est sign of all. The bark is one of the best signs.
It is not the easiest thing in the world to learn to know trees by the bark alone. To the be ginner, so many trees with dark, furrowed bark look strangely alike, although the trees are not even related to each other. The foresters be-. gan with trees that have peculiar and easily recog nised bark. So we shall begin here, and hope that the hard cases will gradually become easier.
Every tree wears a garment of bark from the ground up to the utmost twigs. The thinnest bark is on the youngest branches. The thickest is on the trunk.
Begin with the white birch upon the lawn. The bark of this tree is made of thin layers; the outer one shining like white satin. It breaks and tatters, and peels off around the trunk. Three-cornered patches of black are found under each branch, and others on the trunk show where branches once came out, but were broken or cut off.
Do you notice narrow, horizontal slits of dif ferent lengths on the birch bark? These are breathing holes that let the air in to the layer under the bark. Spongy, porous substance fills these slits, but allows the air to pass through. At the lower part of the trunk the satiny outer bark is shed, leaving dark under layers, rough and checked into irregular blocks. As the tree grows older, the trunk becomes rougher and darker, but the branches always show the kind of bark that the little tree wore.
In the Northern woods the white bark of the canoe birch is stripped from the trees in layers as thick as sole leather. Out of these the Indians once made their bark canoes. Now the same material is used for making all manner of trifling souvenirs to sell to tourists. A square of this thick bark, cut on the smooth side of a trunk, may be split into a great number of thin sheets.
This the camper uses to write letters upon, and it is a beautiful and fitting substitute for note paper, when one is camping out.
It is a great pity that so many beautiful trees are girdled and killed to supply the needs of camping parties. If the bark were stripped but part way around it would not kill the tree.
The yellow birch has a silvery yellow tint in the outer bark, which curls back in ragged rib bons until the tree gets old. The red birch writes its name in the rusty red colour of its pa pery bark, which splits into tatters in true birch fashion, and flutters the ragged ends from each branch throughout the year. The black birch has no tattered ribbons flying, but wears a close, smooth, black bark, with the narrow slits that all birches show. As the trunks 'grow larger the surface checks into irregular plates, separated by furrows. It is called the cherry birch, for the bark is like that of cherry trees.
The sycamore has bark which is different from that of every other tree. Indeed, it is by the bark that we recognise this tree. The tall trunk looks as if it were blotched and streaked and spattered with whitewash, from the trunk to the topmost limb. The bark is continually dropping off in thin, irregular plates, leaving smooth whit ish patches of an under layer exposed. After sycamore trees grow older, the bark of the lower portion of the trunk stops shedding. Fine checked plates of rusty brown cover this oldest portion. But even on the oldest and largest trees, the pale blotches are seen in the branches and we shall never mistake the name of the tree.
The shagbark is one of the rugged and shaggy trees that boys find hard to climb without tearing their clothes into tatters. The bark gives the tree its name. Thin, narrow plates, close-woven and tough as sole leather, seem to be attached very loosely to the body of the tree, but if you try to pull off these narrow strips, you find their hold is very firm. Often they are attached at the middle, and spring out at both ends.