ornamental tree of the family Betulaceae, found on river and stream banks in the eastern one-third of the United States. Because the lower trunk becomes very dark with age, the tree is sometimes called black birch, a name more properly applied to sweet birch (q.v.).

Commonly 18 to 25 m (60 to 80 feet) tall, river birch may reach 30 m in the lower Mississippi River valley. The red-brown, deeply furrowed bark on an old trunk breaks into ragged, closely appressed scales; the upper trunk and branches are smooth, salmon pink to rose cinnamon, with a metallic lustre. The glossy, dark green, wedge-shaped leaves are unevenly double-toothed, with hairy veins below. The hairy, flattened leafstalks are about 1 cm (0.4 inch) long. The tree's fruits mature in late spring or early summer, in contrast to the fall ripening of other birches. The fast-growing river birch has value in erosion control and as an ornamental and street tree. It grows well on moist, well-drained soil but does not tolerate shade. It is fairly immune to disease or insect attack but is short-lived. The wood is used for furniture, woodenware, and turned articles.