Populus balsamifera, commonly called balsam poplar, bam, bamtree, eastern balsam-poplar, hackmatack, tacamahac poplar, tacamahaca, is a tree species in the balsam poplar species group in the poplar genus, Populus. The genus name Populus is from the Latin for poplar, and the specific epithet balsamifera from Latin for "balsam-bearing". Other common names for the species include heartleaf balsam poplar, and Ontario balsam poplar. The black cottonwood, Populus trichocarpa, is sometimes considered a subspecies of P. balsamifera and may lend its common name to this species, although the black poplars and cottonwoods of Populus sect. Aigeiros are not closely related.
Populus balsamifera is the northernmost North American hardwood, growing transcontinentally on boreal and montane upland and flood plain sites, and attaining its best development on flood plains. It is a hardy, fast-growing tree which is generally short lived, but some trees as old as 200 years have been found.
The Balm-of-Gilead (Populus × jackii), also known as P. × gileadensis, is the hybrid between P. balsamifera and the eastern cottonwood (P. deltoides), occurring occasionally where the two parental species' ranges overlap. This hybrid is also sometimes planted as a shade tree, and sometimes escapes from cultivation. The name Populus candicans has been variously used for either P. balsamifera or P. × jackii; it is currently considered a synonym of P. balsamifera.
The light, soft wood of Populus balsamifera is used for pulp and construction.
Many kinds of animals use the twigs of Populus balsamifera for food. The leaves of the tree serve as food for caterpillars of various Lepidoptera. See List of Lepidoptera that feed on poplars.