Properly, any of about 40 species of trees that make up the genus Abies , in the pine family.
Many other evergreen Douglas fir , hemlock fir) are also commonly called firs. True firs are native to North and Central America, Europe, Asia, and northern Africa. They are distinguished from other genera in the pine family by their needlelike leaves, which grow directly from the branch and have bases, shaped like suction cups, that leave conspicuous circular scars when the leaves fall. North America boasts 10 native species of fir, found chiefly from the Rocky Mountains westward. The wood of most western North American firs is inferior to that of pine or spruce but is used for lumber and pulpwood. Of the two fir species that occur in the eastern U.S. and Canada, the better known is the balsam fir ( A. balsamea ), a popular ornamental and Christmas tree.