THE river, or back birch, is at home, as the name implies, along water courses, and inhabits the deep, rich soils along the borders of the larger rivers of the State and in swamps which are sometimes inundated for weeks at a time.
RIVER BIRCH
Two-thirds natural size.
The bark provides a ready means of distinguishing this tree. It varies from reddish-brown to cinnamon-red in color, and peels back in tough papery layers. These layers persist on the trunk, presenting a very ragged and quite distinctive appearance. Unlike the bark of our other birches, the thin papery layers are usually covered with a gray powder. On older trunks, the bark on the main trunk becomes thick, deeply furrowed and of a dark reddish-brown color.
The leaves are simple, alternate, 2 to 3 inches long, more or less oval in shape, with double-toothed edges. The upper surface is dark green and the lower a pale yellowish-green.
The flowers are in catkins, the two kinds growing on the same tree. The fruit is cone-shaped about 1 inch long, and densely crowded with little winged nutlets that ripen from May to June.
The wood is strong and fairly close-grained. It has been used to some extent in the manufacture of woodenware, in turnery and for wagon hubs.
The yellow birch, Betula lutea Michx., one of the most valuable hardwood timber trees around the Great Lakes, is represented in Illinois by a few small trees in Lee and Lake counties. It may be known by its bark becoming silvery-gray as the trunk expands and breaking into strips curled at the edges. The wood is strong and hard, close-grained, light brown tinged with red. It is used for interior finish, furniture, woodenware and turnery. It is prized as firewood.
