Betula alaus. The wood of this tree, which thrives in moist soils, is used on account of its durability, when of considerable dimensions, for piles, mill-work, pumps, and sluices. On account of its variegated colour it is occasionally used in turnery; but one of its most important uses is the excellent charcoal it affords for gunpowder. The bark is astringent, and is used in preparing leather; and the plant has also been used as a dye.