Fir is a common name for a number of handsome evergreen trees that belong to the pine family. Nine species of firs grow in the United States. Most of them grow in the mountains of the West. The Douglas-fir, a valuable timber tree, is not a true fir. It belongs to a separate genus (group) in the pine family.
When it grows in the open, the fir tree is shaped somewhat like a pyramid. It has dense foliage. Its needle-shaped leaves do not grow in clusters like pine needles, but occur evenly all around the branch. They are usually soft, blunt, and fragrant. In many species the needles are dark green above, with light-colored lines on the bottom surface. Firs have distinctive cylinder-shaped cones that grow upright on the branches. When the cones mature, they shed their scales, leaving a bare, spinelike axis. The bark of young firs contains blisters filled with a sticky substance called resin. Resin helps protect firs from wood-boring insects.
Because of their shape and fragrance, true firs are widely used as Christmas trees. Especially popular for this use are the balsam fir and Fraser fir. The balsam fir grows in the northern United States and much of Canada. It may reach 60 feet (18 meters) tall. The Fraser fir grows in the mountains of Virginia, North Carolina, and Tennessee. It stands 30 to 50 feet (9 to 15 meters) tall. 
The firs of western North America become much larger than balsam and Fraser firs. Most western firs are used for timber and paper pulp. The noble fir is the largest true fir. It stands up to 250 feet (76 meters) tall, and its trunk measures up to 8 feet (2.4 meters) in diameter. The noble fir grows only in the Cascade Mountains in Oregon and southern Washington. Its wood is stronger and more valuable than that of other true firs. The grand fir grows in British Columbia, western Washington and Oregon, and in the northern Rocky Mountains. Its nearly odorless white wood is often used for food containers. The California red fir grows in the mountains of California and southern Oregon. The Pacific silver fir is common in Oregon, Washington, and British Columbia. The subalpine fir, the most widespread western fir, grows from central Alaska to southern Arizona. It can live at higher elevations than other firs.
