B. papyracea, the Paper or Canoe-Birch. Catkins thick, pendulous, on long stalks ; branches generally more or less downy when young, sometimes hairy; leaves ovate, occasionally heart-shaped, regularly or irregularly serrated, smooth or downy. This, the most valuable of all the species of Birch, is a native of North America, where it grows in great quantities, not extending beyond 73° to the north nor 43° to the eolith, according to Michaux. The slopes of hills and valleys, where the soil is of good quality, are said to be its favourite stations: in such places it often acquires the height of 70 feet.
Its wood is sometimes used in North America for cabinet makers' work ; but it is not of much value for exposure to the weather, as it soon decays if subjected alternately to damp and dryness. Its bark is the part which is the most esteemed ; this part is said to be so durable that old fallen trees are stated to be frequently found with their form so well preserved that one would think them perfectly sound, but upon examining them it is found that the whole of the wood is rotted away, and nothing is left but the sound and solid case of bark. This part is used for a number of useful purposes ; log houses are sometimes thatched with it ; little boxes, cases, &c., and even bats are manufactured from it; but its great value is for making canoes. For the purpose of obtaining pieces sufficiently large for such a purpose, we are informed by Michaux that the largest and smoothest-barked trees are selected. In the spring two circular incisions at the distance of several feet are made, and a longitudinal incision on each aide ; then by introducing a wedge of wood between the trunk and bark, the latter is easily detached. With threads prepared from the fibrous roots of the White Spruce-Fir (Abler alba), the pieces of bark are sown together, over a light frame-work of wood, and the seams are caulked with the resin of the Balm of Gilead Fir. Canoes
of this sort are so light as to he easily transported on the shoulders of men. It is said that one capable of carrying four persons and their baggage only weighs from 40 to 50 pounds.
B. lento (B. carpinifolia, A. Mich.), the Soft, Black, or Cherry-Birch. Catkins short, erect; branches quite smooth ; leaves thin, oordate, oblong, tapering to a point, simply or doubly serrated, downy when young, smooth afterwards; stipules very large and membranous. None of the American birches produce timber so valuable as this; whence one of its American names is Mountain Mahogany. Its wood is hard, close-grained, and of a reddish brown ; it is imported into this country in considerable quantity, under the name of American birch, for forming the slides of dining-tables,,and for similar purposes. It is abundant in the midland states, as in New York, New Jersey, and Pennsylvania, but more to the south it only appears on the summits of the Alleghenies. Deep rich soil is what it prefers; and when it attains its greatest dimensions, which are as much as 70 feet of height, and 3 feet of diameter, it is a handsome tree, budding remarkably early in the spring, when its leaves are covered with a short thick coat of down ; this disappears later in the season, and leaves them of a bright and lively green. It grows with unusual rapidity. It is rarely seen in this country, although it is perhaps one of the best suited to our climate. The thinness of its leaves, combined with their oblong figure, distinguishes this from all the other species.