Alder-Tree, or the Betula of Linnaeus, is so well known by the name of common birch, as to require no particular description. There are three species, 1. the alba, or common ;2. the nana, or dwarf; and 3. the lenta, or Canada-birch : thelast of which grows to a height of upwards of sixty feet. The al-nus, or alder-tree, is, properly speaking, another species of the Canada-birch. When suffered to grow in an open situation, it has an agreeable appearance. Whenever any soil be intended for pasture, the al-der should by no means be encouraged, as it poisons the herbage, and renders the soil moist and rotten.
The alba, or common birch, is easily propagated; either from seeds or layers, and will flourish in most soils. While in the nursery, they should, in dry weather, be con-stantly weeded and watered. According to Hanbury, the be.->t method of producing them, and preserving their varieties, is by distributing them in layers.
The wood of this tree was, in ancient times, used for die construction of boats, and at present, on account of its hardness, is employed in the North of Europe for making carriages and wheels. In France, it is generally used for wooden shces ; and in England, for women's shoe-heels, travelling boxes, etc; it also affords very good fuel. In Sweden it is employed lor covering houses, and is very durable. On deeply wounding, or boring the trunk of this tree, in the beginning of spring, a sweetish juice exudes in large quantities ; and one branch alone will yield a gallon in a day. This juice is recommended in scorbutic disorders, and other impurities of the blood. Its most sensible effect is in promoting the urinary discharge. By proper fermentation, and with the addition of sugar, it makes a pleasant wine. The plant itself is astringent, but the bark of the black berry-bearing alder, is af-firmed to be the most certain purge for horned cattle. The leaves, when eaten by cows, are said greatly to increase their milk.