The 'Subalpine Fir' or 'Rocky Mountain Fir' (''Abies lasiocarpa'') is a western
North American
fir, native to the
mountains of
Yukon,
British Columbia and western
Alberta in
Canada; southeastern
Alaska,
Washington,
Oregon,
Idaho, western
Montana,
Wyoming,
Utah,
Colorado,
New Mexico,
Arizona, northeastern
Nevada, and the
Trinity Alps in northwestern
California in the
United States. It occurs at high altitudes, from 300-900 m in the north of the range (rarely down to sea level in the far north), to 2,400-3,650 m in the south of the range; it is commonly found at the
tree line.
It is a medium-sized
tree growing to 20 m tall, exceptionally to 40-50 m tall, with a trunk up to 1 m diameter, and a very narrow conic crown. The
bark on young trees is smooth, gray, and with
resin blisters, becoming rough and fissured or scaly on old trees. The
leaves are flat needle-like, 1.5-3 cm long, glaucous green above with a broad stripe of
stomata, and two blue-white stomatal bands below; the fresh leaf scars are reddish. They are arranged spirally on the shoot, but with the leaf bases twisted to be arranged to the sides of and above the shoot, with few or none below the shoot. The
cones are erect, 6-12 cm long, dark blackish-purple with fine yellow-brown pubescence, ripening brown and disintegrating to release the winged
seeds in early fall.
There are two to three
taxa in Subalpine Fir, treated very differently by different authors:
★ The 'Coast Range Subalpine Fir' ''Abies lasiocarpa'' in the narrow sense, is the typical form of the species, occurring in the
Pacific Coast Ranges, the
Olympic Mountains and the
Cascade Range from southeast Alaska (
Panhandle mountains) south to California.
★ The 'Rocky Mountains Subalpine Fir' is very closely related and of disputed status, being variously treated as a distinct species ''Abies bifolia'', as a
variety of Coast Range Subalpine Fir ''Abies lasiocarpa'' var. ''bifolia'', or not distinguished from typical ''A. lasiocarpa'' at all. It occurs in the
Rocky Mountains from southeast Alaska (eastern
Alaska Range) south to Colorado. It differs primarily in
resin composition, and in the fresh leaf scars being yellow-brown, not reddish. The ''Flora of North America'' treats it as a distinct species (see external links, below); the
USDA includes it within ''A. lasiocarpa'' without distinction.
★ The 'Corkbark Fir' ''Abies lasiocarpa'' var. ''arizonica'' occurs in Arizona and New Mexico. It differs in thicker,
corky
bark and more strongly glaucous foliage. In resin composition it is closer to ''A. bifolia'' than to typical ''A. lasiocarpa'', though the combination "Abies bifolia var. arizonica" has not been formally published. The ''Flora of North America'' includes it within ''A. bifolia'' without distinction; the USDA treats it as a distinct variety of ''A. lasiocarpa''.
Uses
The
wood is used for general structural purposes and
paper manufacture. It is also a popular
Christmas tree. Corkbark Fir is a popular
ornamental tree, grown for its strongly glaucous-blue foliage.
References
★
External links
★
Gymnosperm Database: ''Abies lasiocarpa''
★
Flora of North America: ''Abies lasiocarpa''
★
Flora of North America: ''Abies bifolia''