Poplar, common name for any of about 35 species of trees in a genus of the willow family. Poplars are short-lived, fast-growing trees native mostly to the northern hemisphere. The soft wood of poplars is used for paper pulp, in light construction, and in crate making. Poplars are divided into three groups, or subgenera: aspens; balsam poplars; and cottonwoods, so called because of the abundant, cottonlike seeds they produce. The Lombardy poplar, with close, erect branches, is planted as a windbreak. The black cottonwood of western North America is the largest poplar on the continent, attaining heights of more than 80 m (200 ft). See also Aspen.

Scientific classification: Poplars belong to the genus Populus of the family Salicaceae. The Lombardy poplar is classified as Populus nigra cultivar italica, and the black cottonwoods as Populus trichocarpa.