Birch, a tree found in the Northern Hemisphere. The birch family also includes the alder, hazel, hornbeam, and hop-hornbeam trees. Birches are graceful trees, often planted in parks and gardens. They bear tiny catkins (leafy clusters) of flowers without petals. The fruit is a tiny nut.

The paper birch, also called white, or canoe, birch, has brilliant white bark and is especially striking when growing among evergreens. It is found in the cooler parts of eastern North America. The tree reaches a height of nearly 80 feet (24 m) and has oval, toothed leaves. The smooth, white bark is composed of many thin layers. The outer portions can be removed in sheets. Since it contains a resin that makes it watertight, birch bark was used by American Indians to make canoes, buckets, baskets, and many other articles. It is still used for souvenirs and novelty items.

The gray birch resembles the paper birch, but is smaller. The bark is dirty white and the leaves are roughly triangular.

The European white birch is a beautiful tree frequently planted in North America as an ornamental. It looks like the paper birch but is smaller. There are several varieties, some with drooping branches or finely divided leaves.

The yellow birch is an important timber tree. It grows up to 100 feet (30 m) high. The bark is yellow and shaggy, with a pleasing, aromatic oil. The wood is hard and strong and takes a high polish. It is used for furniture and paneling.

The water birch (also called black, or red, birch) is native to northwestern North America, It is about 25 feet (8 m) high. The river birch (also called water, or red, birch) usually grows 60 to 80 feet (18–24 m) high. A useful timber tree with reddish bark, it is found from Massachusetts to Florida.

The sweet, or cherry, birch has reddish, aromatic bark, from which a medicinal oil is obtained. The sap of this tree is sweet, like that of the sugar maple. In some areas it is collected and fermented into birch beer. The wood is used in furniture making.

Birches make up the genus Betula of the birch family, Betulaceae. The paper birch is B. papyrifera; the gray birch, B. populifolia; the European white birch, B. pendula; the yellow birch, B. alleghaniensis; the water birch, B. occidentalis; the river birch, B. nigra ; the sweet birch, B. lenta.