Of the two fir species that occur in the eastern United States and Canada, the best known is the balsam fir (A. balsamea), which is a popular ornamental and Christmas tree. It may be 12 to 18 metres (about 40 to 60 feet) tall at maturity, with cones 5 to 10 cm (about 2 to 4 inches) long. Canada balsam, an oleoresin collected from pitch blisters on the balsam fir’s bark, is used to mount specimens on glass slides for microscopic examination.
