Subalpine Fir – Abies lasiocarpa

Two varieties are recognized: the typical variety (Abies lasiocarpa var. lasiocarpa) and corkbark fir (Abies lasiocarpa var. arizonica). The latter, readily distinguished by its peculiar, whitish, corky bark, is restricted to the Rocky Mountains of southern Colorado and the Southwest. Other common names for the typical variety include balsam, white balsam, alpine fir, western balsam fir, balsam fir, Rocky Mountain fir, white fir, and pino real blanco de las sierras; corkbark fir, alamo de la sierra. (Yikes!)

Subalpine fir is a widely distributed North American fir. Its range extends from 32° N. latitude in Arizona and New Mexico to 64° 30 N. in Yukon Territory, Canada. Along the Pacific coast, the range extends from southeastern Alaska, south of the Copper River Valley (lat. 62° N.), the northwestern limit; east to central Yukon Territory (lat. 64° 30' N.), the northern limit; south through British Columbia along the east slopes of the Coast Range to the Olympic Mountains of Washington, and along both slopes of the Cascades to southern Oregon. It is not found on the west slopes of the Coast Range in southern British Columbia or along the Coast Range in Washington and Oregon, but it does occur on Vancouver Island. It is also found locally in northeastern Nevada and northwestern California. Except where noted above, subalpine fir is a major component of high elevation Pacific Northwest forests.(2)

Flowering and Fruiting- Subalpine fir flowers are monoecious. Male flowers, usually abundant, are borne in pendulous clusters from the axils of the needles on the lower branchlets. Female flowers are fewer, borne erect and singly on the uppermost branchlets of the crown. Male flowers ripen, and pollen is wind-disseminated, during late spring and early summer. Cones are indigo blue when they open in mid-August to mid-October. Seed ripens from mid-September to late-October.

Seed Production and Dissemination- Subalpine fir may begin to produce cones when trees are 1.2 to 1.5 m (4 to 5 ft) tall and 20 years old, but under closed-forest conditions, seed production is not significant until trees are older and taller. Corkbark fir does not begin to bear cones until about 50 years old. Maximum seed production for subalpine and corkbark fir occurs in dominant trees 150 to 200 years old.

Subalpine fir is a good seed producer in the Pacific Northwest and in the Rocky Mountains of Idaho and Montana, with good to heavy crops borne every 3 years, and light crops or failures in between. It is as good a seed producer as most associated true firs, but not as good as the hemlocks and Engelmann spruce.

Throughout much of the Rocky Mountains, subalpine fir has no special or unique properties. In the high Cascades and in the Rocky Mountains of Idaho and Montana, it is a forest pioneer on severe and disturbed sites. By providing cover, subalpine fir assists in protecting watersheds and rehabilitating the landscape. Forests in which subalpine fir grows occupy the highest water yield areas in much of the West.

The species also provides habitat for various game and nongame animals, forage for livestock, recreational opportunities, and scenic beauty. However, these properties are indigenous to the sites where subalpine fir grows rather than to any special properties associated with the species.

Fir is used as lumber in building construction, boxes, crates, planing mill products, sashes, doors, frames, and food containers. It has not been widely used for pulpwood because of inaccessibility, but it can be pulped readily by the sulfate or groundwood processes. (2)