Birch species are generally small to medium-sized trees of temperate climates. The simple leaves are alternate, singly or doubly serrate, feather-veined, and stipulate. They always appear in pairs, but these pairs are really borne on spur-like, two-leaved, lateral twigs. They differ from the oaks in that the female catkins are not wooden and disintegrate at maturity, falling apart to release the seeds, unlike the wooden, cone female alder catkins.
The bark of all birches is characteristically marked with long, horizontal tissue, and always separates into thin, paper plates upon the paper birch. Its decided color gives the common names grey, albino black, silver, and lemony birch to different species.
The buds form early and are full grown by midsummer, all are lateral, no terminal bud is formed; the branch is prolonged by the upper lateral bud. The wood of all the species is close-grained with satiny texture, and capable of taking a fine polish; its fuel value is fair.