Robert R. Alexander, Raymond C. Shearer, and Wayne D. Shepperd
Subalpine fir, the smallest of eight species of true fir indigenous to the western United States, is distinguished by the long, narrow conical crown terminating in a conspicuous spikelike point.
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; for corkbark fir, alamo de la sierra (44).
General: Pine Family (Pinaceae). Native, evergreen trees growing to 20 meters tall with a sharp, spire-like crown, the upper several feet often less than 30 cm in diameter, the plants often reduced to a prostrate shrub on exposed sites near timberline. Bark is smooth, grayish-white, with resin blisters, becoming furrowed only when the tree approaches a foot in diameter (or var. arizonica, see below, with a softer, corky trunk); branches with bark splitting to reveal a reddish-brown layer; leaf scars with periderm red (or tan in var. arizonica). Needles are 1.8-3 cm long, flattened, grooved and bluish-green waxy on the upper surface, 1-ranked and tending to turn upward so that the foliage of a particular branch appears flattened and as though no leaves were attached to the lower sides of the twigs; resin canals median, located between the upper and lower epidermis. Seed cones are 6-12 cm long, 2-4 cm wide, dark purple, erect and only on the uppermost branches. The common name refers to the distribution of the species in the subalpine zone.
Variation within the species: Taxonomy of the species is not settled. Abies bifolia A. Murr. may be treated within A. lasiocarpa or as a separate species (evidence summarized by Hunt 1993). A southern population system (Arizona, New Mexico, Colorado) is sometimes recognized as A. lasiocarpa var. arizonica (Merriam) Lemmon (corkbark fir), or it may be identified as part of A. bifolia.
Abies lasiocarpa in the broad sense is distinguished from A. balsamea by 4-5 stomatal rows on the upper surface at midleaf (vs. mostly 7 rows in A. balsamea).
Regularity: Regularly occurring
Regularity: Regularly occurring
Global Range: Southeastern Alaska, western Canada, south to Oregon, Arizona, and New Mexico.
Occurrence in North America
WY AB BC YT
spanning more than 32 degrees of latitude . It occurs chiefly in
mountainous areas from the Yukon interior near treeline and along the
coast of southeastern Alaska south through western Alberta and British
Columbia to southern Colorado and scattered mountain ranges of Arizona
and New Mexico [54,75]. In the western portion of its range, subalpine
fir does not occur along the western slope of the Coast Range in
southern British Columbia or along the Coast Ranges of Washington and
Oregon but does occur on Vancouver Island and in the Olympic Mountains
of Washington . It occurs on both slopes of the Cascade Mountains
as far south as southern Oregon . The two varieties are distributed
as follows [11,75]:
var. lasiocarpa - almost the same as the species, but not in central and
var. arizonica - from central Colorado to southwestern New Mexico, and
in southeastern and central Arizona.
Subalpine fir and corkbark fir occur together in scattered mountain
ranges in southwestern Colorado, northern, western, and southwestern New
Mexico, and in the high mountains of Arizona .
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
1 Northern Pacific Border
2 Cascade Mountains
5 Columbia Plateau
6 Upper Basin and Range
8 Northern Rocky Mountains
9 Middle Rocky Mountains
11 Southern Rocky Mountains
12 Colorado Plateau
In the Rocky Mountain region, subalpine fir extends from the interior valleys of British Columbia west of the Continental Divide and south of the Peace River (lat. 55° N.), south along the high elevations of the Rocky Mountain system to southern New Mexico and Arizona. In the north, its range extends from the high mountains of central British Columbia, western Alberta, northeastern Washington, northeastern Oregon, Idaho, Montana, to the Wind River Mountains of western Wyoming. In Utah, it commonly occurs in the Uinta and Wasatch Mountains, but is less abundant on the southern plateaus. The range extends from southern Wyoming, through the high mountains of Colorado and northern New Mexico, and westward through northeastern Arizona to the San Francisco Mountains (2,9). Subalpine fir is a major component of the high-elevation forests of the Rocky Mountains.
Corkbark fir is found mixed with subalpine fir on scattered mountains in southwestern Colorado; northern, western, and southwestern New Mexico; and in the high mountains of Arizona (44).
- The native range of subalpine fir.
Subalpine fir grows in subalpine coniferous forests, 600-3600 meters, up to timberline, often associated with Douglas fir, Engelmann spruce, and blue spruce. It is restricted to cold, humid habitats because of low tolerance to high temperatures. Cool summers, cold winters, and deep winter snowpacks are more important than total precipitation in differentiating where subalpine fir grows in relation to other species.
Subalpine fir is widespread in western North America, from southeastern Alaska, Yukon, and Mackenzie south to California, in the Rocky Mountains to northeastern Arizona and New Mexico. For current distribution, please consult the Plant Profile page for this species on the PLANTS Web site.
Subalpine fir is a native, coniferous, evergreen tree. It is the
smallest of the eight species of fir native to the western United
States. Five growth forms, each apparently an adaptation to a
particular environment, are described below [9,54]:
1. The typical form is found throughout much of the subalpine zone.
These trees have an extremely narrow and dense crown with short
branches. Trees growing in openings retain their lower branches, which
often droop and extend down to the ground. Trees growing in the
overstory may be clear of lower branches for 20 to 30 percent of the
2. A somewhat broad-crowned, bullet-shaped tree is more typical of
older specimens and drier climates.
3. A mature tree with a layered apron is occasionally found in some
4. A flag form tree often occurs at timberline. These individuals are
characterized by an upright trunk that extends above a krummholzlike
mat. Branches on the trunk generally grow only along the leeward side
of the trunk, giving the plant a flaglike appearance.
5. The krummholz form is typical of alpine areas above timberline. In
these areas, because of cold temperatures and severe winds, subalpine
fir grows in dwarfed, shrubby mats along the ground, and is often much
broader than it is tall.
The typical form often grows to heights of 60 to 100 feet (18-30 m), and
trunk diameters reach 18 to 24 inches (46-61 cm) . Trees up to 130
feet (40 m) tall and 30 inches (76 cm) in diameter have been found but
are rare . Subalpine fir grows very slowly; 150- to 200-year-old
trees are usually only 10 to 20 inches (25-50 cm) in diameter .
Trees seldom live more than 250 years because they are very susceptible
to heart rots .
Needles are blunt tipped, flattened, and 1 to 1.2 inches (2.5-3 cm) long
[25,57]. Bark on young trees is thin, gray, and smooth, with numerous
resin vesicles; on older trees it is shallowly fissured and scaly .
Corkbark fir is generally recognized by its creamy-white, thick, corky
bark . The root system generally is shallow but under favorable
conditions may develop relatively deep laterals .
Subalpine fir is monoecious. Single or small bunches of erect female
cones occur in the upper part of the crown on the upper side of young
branches. Dense clusters of the smaller male cones occur lower on the
crown on the underside of 1-year-old twigs. Subalpine fir seeds are
0.23 to 0.28 inch (6-7 mm) long and have broad wings about 0.4 inch (1
cm) long [25,121]. Corkbark fir seeds are about 70 percent larger than
subalpine fir seeds .
Arizona Mountains Forests Habitat
This taxon is found in the Arizona Mountain Forests, which extend from the Kaibab Plateau in northern Arizona to south of the Mogollon Plateau into portions of southwestern Mexico and eastern Arizona, USA. The species richness in this ecoregion is moderate, with vertebrate taxa numbering 375 species. The topography consists chiefly of steep foothills and mountains, but includes some deeply dissected high plateaus. Soil types have not been well defined; however, most soils are entisols, with alfisols and inceptisols in upland areas. Stony terrain and rock outcrops occupy large areas on the mountains and foothills.
The Transition Zone in this region (1980 to 2440 m in elevation) comprises a strong Mexican fasciation, including Chihuahua Pine (Pinus leiophylla) and Apache Pine (P. engelmannii) and unique varieties of Ponderosa Pine (P. ponderosa var. arizonica). Such forests are open and park-like and contain many bird species from Mexico seldom seen in the U.S.. The Canadian Zone (above 2000 m) includes mostly Rocky Mountain species of mixed-conifer communities such as Douglas-fir (Pseudotsuga menziesii), Engelmann Spruce (Picea engelmanni), Subalpine Fir (Abies lasiocarpa), and Corkbark Fir (A. lasiocarpa var. arizonica). Dwarf Juniper (Juniperus communis) is an understory shrubby closely associated with spruce/fir forests. Exposed sites include Chihuahua White Pine (Pinus strobiformis), while disturbed north-facing sites consists primarily of Lodgepole Pine (Pinus contorta) or Quaking Aspen (Populus tremuloides).
There are a variety of mammalian species found in this ecoregion, including the endemic Arizona Gray Squirrel (Sciurus arizonensis), an herbivore who feeds on a wide spectrum of berries, bark and other vegetable material. Non-endemic mammals occurring in the ecoregion include: the Banner-tailed Kangaroo Rat (Dipodomys spectabilis NT); Desert Pocket Gopher (Geomys arenarius NT). In addition, there is great potential for restoring Mexican Wolf (Canis lupus) and Grizzly Bear (Ursus arctos horribilis) populations in the area because of its remoteness and juxtaposition to other ecoregions where these species were formerly prevalent.
There are few amphibians found in the Arizona mountain forests. Anuran species occurring here are: Red-spotted Toad (Anaxyrus punctatus); Southwestern Toad (Anaxyrus microscaphus); New Mexico Spadefoot Toad (Spea multiplicata); Woodhouse's Toad (Anaxyrus woodhousii); Northern Leopard Frog (Lithobates pipiens); Chiricahua Leopard Frog (Lithobates chiricahuensis VU); Madrean Treefrog (Hyla eximia), a montane anuran found at the northern limit of its range in this ecoregion; Boreal Chorus Frog (Anaxyrus woodhousii); Western Chorus Frog (Pseudacris triseriata); and Canyon Treefrog (Hyla arenicolor). The Jemez Mountains Salamander (Plethodon neomexicanus NT) is an ecoregion endemic, found only in the Jemez Mountains of Los Alamos and Sandoval counties, New Mexico. Another salamander occurring in the ecoregion is the Tiger Salamander (Ambystoma tigrinum).
A number of reptilian taxa occur in the Arizona mountains forests, including: Gila Monster (Heloderma suspectum NT), often associated with cacti or desert scrub type vegetation; Narrow-headed Garter Snake (Thamnophis rufipunctatus), a near-endemic found chiefly in the Mogollon Rim area; Sonoran Mud Turtle (Kinosternon sonoriense NT).
Habitat and Ecology
Var. arizonica is most commonly mixed with Picea engelmannii, Pinus aristata and P. flexilis, or it occurs in pure stands, at elevations between 2,400 and 3,650 m a.s.l.
Comments: Forested flats and slopes to subalpine slopes near timberline.
Subalpine fir is a middle to upper elevation mountain conifer. It
generally occupies sites with a short growing season caused by cold
winters, cool summers, frequent summer frosts, and heavy snowpack. It
forms extensive forests between warm and dry lower elevation forests of
Douglas-fir, white fir (Abies concolor), grand fir, lodgepole pine, or
blue spruce (Picea pungens) and higher elevation alpine tundra
[23,29,112,125]. At its lower elevational limits, subalpine fir is
often restricted to streambottoms, ravines, frosty basins, or north
exposures. It increasingly occupies westerly and easterly aspects with
increasing elevation and may occupy all aspects at upper timberline
Stand condition and associated conifers: Throughout its range,
subalpine fir is most commonly associated with Engelmann spruce. These
two species frequently occur as codominants forming widespread subalpine
forests. In the central and southern Rocky Mountains, Engelmann spruce
commonly makes up 70 percent of overstory trees, with subalpine fir
dominating the understory . Within spruce-fir forests of this
region, Engelmann spruce tends to be more important at higher elevations
and on wetter sites, while subalpine fir is more abundant on drier lower
elevation sites . In the northern Rocky Mountains, subalpine fir
typically dominates climax stands, but Engelmann spruce becomes
increasingly important on moist, cool sites [23,91]. Other associates
which vary by latitude and elevation are listed below :
Location Elevation Associates
northern Rocky Mtns low western white pine (Pinus monticola),
Douglas-fir, western larch (Larix
occidentalis), grand fir, western hemlock
(Tsuga heterophylla), western redcedar
high lodgepole pine, subalpine larch (Larix
lyallii), whitebark pine (Pinus
albicaulis), mountain hemlock
central Rocky Mtns low lodgepole pine, Douglas-fir, aspen
(Populus tremuloides), blue spruce
high whitebark pine, limber pine (Pinus
flexilis), bristlecone pine (P. aristata)
southern Rocky Mtns low white fir, Douglas-fir, blue spruce, aspen
high corkbark fir
Cascade Mtns low Pacific silver fir, mountain hemlock,
high mountain hemlock, whitebark pine
Understory associates: Understory vegetation is extremely variable,
changing with elevation, exposure, and soil moisture. Habitat type and
plant association guides describe characteristic understory plants for
Elevation: Alexander and others  described the following
elevational ranges for subalpine fir:
Coast Range of southeastern Alaska - subalpine fir is found from sea
level to 3,500 feet (0-1,067 m).
Coast Range and interior plateaus of Yukon Territory and British
Columbia - subalpine fir is found from 2,000 to 5,000 feet (610-1,524
Olympic and Cascade Mountains of Washington and Oregon - subalpine fir
is generally found from 4,000 to 6,000 feet (1,219-1,829 m), but may be
found as low as 2,000 feet (610 m) along cold streambottoms and on lava
flows, and as high as 8,000 feet (2,438 m) on sheltered slopes.
Rocky Mountains of British Columbia and Alberta south of the Peace River
- subalpine fir is found from 3,000 to 7,000 feet (914-2,134 m) but is
more abundant above 5,000 feet (1,524 m).
Rocky Mountains of Montana and Idaho and associated ranges of eastern
Oregon and Washington - subalpine fir grows from 2,000 to 11,000 feet
(610-3,353 m) but is most common at 5,000 to 9,000 feet (1,524-2,743 m).
Rocky Mountains of Wyoming, Utah, and Colorado - subalpine fir occurs
from 8,000 to 11,500 feet (2,438-3,506 m) but is most common at 9,000 to
11,000 feet (2,743-3,353 m).
Rocky Mountains of New Mexico and Arizona - subalpine fir occurs from
8,000 to 12,000 feet (2,438-3,658 m) but is usually found on north
slopes from 9,500 to 11,000 feet (2,896-3,353 m).
Key Plant Community Associations
Forests in which subalpine fir attains climax dominance or codominance
are widespread throughout the mountains of western North America. The
subalpine fir series generally occupies cold, high elevation mountain
forests. Engelmann spruce (Picea engelmannii) is usually associated
with subalpine fir. It occurs as either a climax codominant or as a
persistent, long-lived seral species in most subalpine fir habitat
Published classification schemes listing subalpine fir as a dominant
part of the vegetation in habitat types (hts), community types (cts),
plant associations (pas), ecosystem associations (eas), site types (sts)
or dominance types (dts) are presented below:
Area Classification Authority
AK: ----- general veg. cts Viereck & Dyrness 1980
AZ: San Francisco forest, alpine &
Peaks RNA meadow cts Rominger & Paulik 1983
AZ, NM: ----- forest & woodland hts Layser & Schubert 1979
Cibola NFs forest hts Fitzhugh & others 1987
s of Mogollon
Rim forest hts Develice & Ludwig 1983b
n AZ, n NM forest hts Larson & Moir 1987
CO: Arapaho &
Roosevelt NFs forest hts Hess & Alexander 1986
Uncompahgre NFs forest hts Komarkova & others 1988
Routt NF forest hts Hoffman & Alexander 1980
White River- grassland, shrubland,
Arapaho NF & forestland hts Hess & Wasser 1982
White River NF forest hts Hoffman & Alexander 1983
w CO riparian pas Baker 1989a
ID: Sawtooth, White
& Pioneer Mtns general veg. cts Schlatterer 1972
c ID forest hts Steele & others 1981
n ID forest hts Cooper & others 1987
se ID aspen cts Mueggler & Campbell 1986
e ID, w WY forest hts Steele & others 1983
MT: ----- forest hts Pfister & others 1977
----- riparian dts Hansen & others 1988
c, e MT riparian cts, hts Hansen & others 1990
nw MT riparian hts, cts Boggs & others 1990
sw MT riparian rst, cts, hts Hansen & others 1989
NM: Cibola NF forest hts Alexander & others 1987
Lincoln NF forest hts Alexander & others 1984
n NM, s CO forest hts Develice & Ludwig 1983a
n NM, s CO forest hts Develice & others 1986
OR: Wallowa-Whitman NF steppe & forest pas Johnson & Simon 1987
Wilderness general veg. cts Cole 1982
OR, WA: ----- general veg. cts Franklin & Dyrness 1973
Blue Mtns general veg. pas Hall 1973
UT: ----- aspen cts Mueggler & Campbell 1986
c, s UT forest hts Youngblood & Mauk 1985
n UT forest hts Mauk & Henderson 1984
WA: Okanogan NF forest pas Williams & Lillybridge 1983
Mount Rainier NP forest pas Franklin & others 1988
North Cascades NP forest pas Agee & Kertis 1987
e WA, n ID forest hts, cts Daubenmire & Daubenmire 1968
WY: Bridger-Teton NF aspen cts Youngblood & Mueggler 1981
Medicine NF forest hts Alexander & others 1986
Bighorn Mtns forest hts Hoffman & Alexander 1976
Wind River Mtns forest hts Reed 1976
USFS R-2 general veg. pas Johnston 1987
USFS R-2 general veg. hts,pas Wasser & Hess 1982
USFS R-4 aspen cts Mueggler 1988
w-c AB forest cts Corns 1983
BC: ----- grassland, forest hts McLean 1970
----- general veg. eas Pojar & others 1984
nw BC forest eas Haeussler & others 1985
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES22 Western white pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES26 Lodgepole pine
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
201 White spruce
202 White spruce - paper birch
205 Mountain hemlock
206 Engelmann spruce - subalpine fir
208 Whitebark pine
209 Bristlecone pine
210 Interior Douglas-fir
212 Western larch
213 Grand fir
215 Western white pine
216 Blue spruce
218 Lodgepole pine
219 Limber pine
223 Sitka spruce
224 Western hemlock
226 Coastal true fir - hemlock
253 Black spruce - white spruce
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K004 Fir - hemlock forest
K012 Douglas-fir forest
K015 Western spruce - pine forest
K018 Pine - Douglas-fir forest
K020 Spruce - fir - Douglas-fir forest
K021 Southwestern spruce - fir forest
K052 Alpine meadows and barren
Soils and Topography
In the central and southern Rocky Mountains subalpine zone, soil materials vary according to the character of the bedrock from which they originated. Crystalline granite rock predominates, but conglomerates, shales, sandstones, basalts, and andesites commonly occur. Glacial deposits and stream alluvial fans are also common along valley bottoms. Of the great soils group, Cryorthods (Podzolic Soils) and Haplorthods (Brown Podzolic Soils) occur extensively on all aspects. Cryochrepts (Sols Bruns Acides) occur extensively on the drier aspects. Aquods (Ground-Water Podzolic Soils) are found in the more poorly drained areas. Cryoboralfs (Gray-Wooded Soils) have fine-textured parent material and support low-density timber stands. Haploboralls (Brown Forest Soils) occur mostly in the lower subalpine zone along stream terraces and side slopes. Lithics (Lithosolic Soils) occur whenever bedrock is near the surface. Aquepts (Bog Soils) and Haplaquepts (Humic Gley Soils) occur extensively in poorly drained upper stream valleys (31,61).
Regardless of the great soils groups that occur in the subalpine zone of the west, subalpine fir is not exacting in its soil requirements. It is frequently found growing on soils that are too wet or too dry for its common associates. Good growth is made on lower slopes, alluvial floodplains, and glacial moraines; and at high elevations on well drained, fine- to medium-textured sand and silt loams that developed primarily from basalt, andesite, and shale. Growth is poor on shallow and coarse-textured soils developed from granitic and schistic rock, conglomerates, and coarse sandstones, and on saturated soils, but subalpine fir establishes on severe sites, such as lava beds, tallus slopes, and avalanche tracks, before any of its common associates. Under these conditions it may pioneer the site for other species or it may exclude the establishment of other species (9,23).
Subalpine fir grows near sea level at the northern limit of its range, and as high as 3658 m (12,000 ft) in the south. In the Coast Range of southeastern Alaska, it is found from sea level to 1067 m (3,500 ft); in the Coast Range and interior plateaus of Yukon Territory and British Columbia, at 610 to 1524 m (2,000 to 5,000 ft); and in the Olympic and Cascade Mountains of Washington and Oregon, generally at 1219 to 1829 m (4,000 to 6,000 ft), but as low as 610 m (2,000 ft) along cold stream bottoms and on lava flows, and as high as 2438 m (8,000 ft) on sheltered slopes (9,57).
In the Rocky Mountains of British Columbia and Alberta south of the Peace River, subalpine fir grows at 914 to 2134 m (3,000 to 7,000 ft), but it is more abundant above 1524 m (5,000 ft); in the Rocky Mountains of Montana and Idaho and associated ranges in eastern Washington and Oregon, at 610 to 3353 m (2,000 to 11,000 ft), but it is more common at 1524 to 2743 m (5,000 to 9,000 ft) (40,41); in the Rocky Mountains of Wyoming, Utah, and Colorado, usually at 2743 to 3353 m (9,000 to 11,000 ft), but it may be found as low as 2438 m (8,000 ft) and to timberline at 3505 m (11,500 ft); and in the Rocky Mountains and associated ranges of New Mexico and Arizona, at 2438 to 3658 m (8,000 to 12,000 ft), but usually on north slopes at 2896 to 3353 m (9,500 to 11,000 ft) (9,12,46,52).
Table 1- Climatological data for four regional subdivisions within the range of subalpine fir. Average temperature
Frost each period Location Annual July January Annual Precip. Annual snowfall °C °F °C °F °C °F cm in cm in days Pacific Northwest -1 to 4 30-35 7-13 45-55 -9 to -4 15-25 61-254+ 24-100+ 1524+ 600+ 30-60 U.S. Rocky Mountains Northern¹ -4 to 2 25-35 7-13 45-55 -15 to -9 5-15 61-152 24-60 635+ 250+ 30*-60 Central² -1 to 2 30-35 10-13 50-55 -12 to -9 10-15 61-140 24-55 381-889+ 150-350+ 30*-60 Southern³ -1 to 4 30-40 10-16 50-60 -9 to -7 15-20 61-102+ 24-40+ 508 200+ 30*-75 ¹Includes the Rocky Mountains north of Wyoming and Utah, and associated ranges in eastern Washington and Oregon.
²Includes the Rocky Mountains of Colorado, Wyoming and Utah.
³Includes the Rocky Mountains and associated ranges of New Mexico and Arizona, and the plateaus of southern Utah.
*Frost may occur any month of the year.
Trees of subalpine fir may begin to produce cones when 20 years old, but under closed-forest conditions, seed production is not significant until trees are older. Corkbark fir does not begin to bear cones until about 50 years old. Maximum seed production occurs in dominant trees 150-200 years old.
Germination and early survival are generally best on exposed mineral soil and moist humus, but a wide variety of other seedbed types also provide adequate conditions. Spring planting is most successful. Subalpine fir invades and establishes on open, severe or disturbed sites near timberline because of its ability to establish a root system under conditions too severe for its less hardy associates and its ability to reproduce by layering.
Subalpine fir is relatively slow growing. Seedlings average less than 38 cm in height after 15 years in the open. Heart rot is a severe problem, and many trees die or are complete culls at an early age. Of those reaching maturity, trees 25-51 cm in diameter are often 150-200 years old, and trees older than 250 years are not uncommon. Some trees in Olympic National Park, Washington, have been determined to be over 400 years old (by ring count).
Associated Forest Cover
SAF Type No. Type Name 201 White Spruce 202 White Spruce-Paper Birch 205 Mountain Hemlock 208 Whitebark Pine 209 Bristlecone Pine 210 Interior Douglas-Fir 212 Western Larch 213 Grand Fir 215 Western White Pine 216 Blue Spruce 217 Aspen 218 Lodgepole Pine 219 Limber Pine 223 Sitka Spruce 224 Western Hemlock 226 Coastal True Fir-Hemlock Differences in elevation and latitude affect temperature and precipitation, influencing the composition of the forests where subalpine fir grows (16). In Alaska and the Coast Range of British Columbia south through the Coast Range of Washington and Oregon, mountain hemlock (Tsuga mertensiana) is its common associate. In Alaska and northern British Columbia, Alaska-cedar (Chamaecyparis nootkatensis) mixes with it; and where it approaches sea level, it mingles with Sitka spruce (Picea sitchensis). From southern British Columbia southward through much of the Cascades, Pacific silver fir (Abies amabilis), mountain hemlock, and lodgepole pine (Pinus contorta) are the most common associates under closed forest conditions. Major timberline associates are mountain hemlock and whitebark pine (Pinus albicaulis). Engelmann spruce is not a constant associate of subalpine fir except on the east slopes of the northern Cascades, and on exceptionally moist, cool habitats scattered throughout the southern and western Cascades. Engelmann spruce is a major associate of subalpine fir in the mountains of eastern Washington and Oregon. Less common associates in the Pacific Northwest include western hemlock, noble fir (Abies procera), grand fir (Abies grandis), western white pine (Pinus monticola), western larch (Larix occidentalis), and alpine larch (Larix Iyallii) (2,9).
From the mountains and interior plateaus of central British Columbia southward through the Rocky Mountain system, where subalpine fir frequently extends to timberline, its most constant associate is Engelmann spruce. Less common associates include: in British Columbia and western Alberta, white spruce (Picea glauca), balsam poplar (Populus balsamifera), paper birch (Betula papyrifera), and aspen (Populus tremuloides); in the Rocky Mountains of Montana and Idaho at its lower limits, western white pine, interior Douglas-fir (Pseudotsuga menziesii var. glauca), western hemlock (Tsuga heterophylla), western larch, grand fir, and western redcedar (Thuja plicata); and at higher elevations, lodgepole pine, alpine larch, mountain hemlock, and whitebark pine. In the Rocky Mountains of Wyoming, Utah, and Colorado, near its lower limits, associates are lodgepole pine, interior Douglas-fir, aspen, and blue spruce (Picea pungens); and at higher elevations, whitebark pine, limber pine (Pinus flexilis), and bristlecone pine (Pinus aristata); and in the Rocky Mountains and associated ranges of New Mexico and Arizona, near its lower limits, white fir (Abies concolor), interior Douglas-fir, blue spruce, and aspen; and at higher elevations, corkbark fir. Subalpine fir frequently extends to timberline in the Rocky Mountains. Other species that accompany it to timberline are whitebark pine, mountain hemlock, and occasionally Engelmann spruce in the Rocky Mountains north of Utah and Wyoming; Engelmann spruce in the Rocky Mountains north of Wyoming, Utah, and Colorado; and Engelmann spruce and corkbark fir in the Rocky Mountains and associated ranges south of Wyoming and Utah (2,9).
At timberline in the Rocky Mountains, subalpine fir and Engelmann spruce form a wind Krummholz I to 2 m (3 to 7 ft) high. On gentle slopes below timberline, subalpine fir, Engelmann spruce, and occasionally lodgepole pine grow in north-south strips 10 to 50 m (33 to 164 ft) wide and several hundred meters long approximately at right angles to the direction of prevailing winds. These strips are separated by moist subalpine meadows 25 to 75 m (82 to 246 ft) wide where deep snow drifts accumulate (14).
Undergrowth vegetation is more variable than tree associates. In the Pacific Northwest and the Rocky Mountains and associated ranges north of Utah and Wyoming, common undergrowth species include: Labrador tea (Ledum glandulosum), Cascades azalea (Rhododendron albiflorum), rusty skunkbrush (Menziesia ferruginea), woodrush (Luzula hitchcockii), Rocky Mountain maple (Acer glabrum), twinflower (Linnaea borealis), dwarf huckleberry (Vaccinium caespitosum) and blue huckleberry (V. globulare) (cool, moist sites); queens cup (Clintonia uniflora), twistedstalk (Streptopus amplexiflolius), and sweetscented bedstraw (Galium triflorum) (warm, moist sites); grouse whortleberry (V. scoparium), fireweed (Epilobium angustifolium), mountain gooseberry (Ribes montigenum), heartleaf arnica (Arnica cordifolia), beargrass (Xerophyllum tenax), boxleaf myrtle (Pachystima myrsinites), elksedge (Carex geyeri), and pine grass (Calamagrostis rubescens (cool, dry sites); creeping juniper (Juniperus communis), white spirea (Spiraea betulaefolia), Oregongrape (Berberis repens), a mountain snowberry (Symphoricarpos oreophilus), and big whortleberry (V. membranaceum) (warm, dry sites); and marsh-marigold (Caltha biflora), devilsclub (Oplopanax horrida), and bluejoint reedgrass (Calamagrostis canadensis) (wet sites) (6,22).
Undergrowth characteristically found in the Rocky Mountains and associated ranges south of Idaho and Montana includes: mountain bluebells (Mertensia ciliata) and heartleaf bittercress (Cardamine cordifolia) (cool, moist sites); thimbleberry (Rubus parviflorus) (warm, moist sites); red buffaloberry (Shepherdia canadensis), Oregongrape, creeping juniper, mountain snowberry (warm, dry sites); and Rocky Mountain whortleberry (V myrtillus), grouse whortleberry, fireweed, heartleaf arnica, groundsel (Senecio sanguiosboides), polemonium (Polemonium delicatum), daisy fleabane (Erigeron eximius), elksedge, boxleaf myrtle, prickly currant (Ribes lacustre), sidebells pyrola (Pyrola secunda), and mosses (cool, dry sites) (6).
Diseases and Parasites
Subalpine fir is attacked by several insects (39). In spruce-fir forests, the most important insect pests are the western spruce budworm (Choristoneura occidentalis) and western balsam bark beetle (Dryocoetes confusus). The silver fir beetle (Pseudohylesinus sericeus) and the fir engraver (Scolytus ventralis) may at times be destructive locally (25). In the Cascades, the balsam woolly adelgid (Adelges piceae), introduced from Europe, is the most destructive insect pest. This insect has caused significant mortality to subalpine fir, virtually eliminating it from some stands in Oregon and southern Washington (22).
Fir broom rust (Melampsorella caryophyllacearum) and wood rotting fungi are responsible for most disease losses (13,29,53). Important root and butt rots are Gloeocystidiellum citrinum, Coniophora puteana, Armillaria mellea, Coniophorella olivaea, Polyporus tomentosus var. circinatus, and Pholiota squarrose. Important trunk rots are Haematostereum sanguinolentum, Phellinus pini, and Amylostereum chailletii. Wood rots and broom rust weaken affected trees and predispose them to windthrow and windbreak (5).
Subalpine fir bark is thin, especially on young trees, and lower limbs persist after death (9). These characteristics make subalpine fir susceptible to death or severe injury from fire.
Fire Management Implications
kill all or nearly all seed trees within a burned area. If subalpine
fir is to naturally regenerate on this type of burn, seeds must come
from adjacent unburned stands. Because subalpine fir seeds are
dispersed over relatively short distances, initial seedling
establishment is restricted to the burn's edge. Subalpine fir cone
production can be erratic from year to year, with the best regeneration
occurring during good seed crop years.
The burned site is a southwest facing gentle slope at an elevation of
5,596 to 5,776 feet (1,706-1,761 m). A total of 27 acres (10.9 ha) were
Climate: The climate is typical of most areas within the subalpine
zone. The winters are cold and wet and the summers cool and dry. Frost
and freezing temperatures can occur during any month of the year. Over
70 percent of precipitation falls as snow between October and March.
Soil and duff: The two stands have similar soils, but the soil in the
snag area is more fertile and better developed. In both areas soils
are derived from basalt residium, have a clay-loam texture, and average
6 inches (15.2 cm) deep. The effective rooting depth was about 20
inches (51 cm) in the thicket area, and 20 to 40 inches (51-102 cm) in
the snag area. On both areas, duff was generally from 1 to 4 inches
(0.4-1.6 cm) thick. The mean depth of duff was 2.3 inches (5.94 cm) on
the thicket area, and 1.9 inches (4.92 cm) on the snag area.
Fuel loading: Prior to burning, mean fuel loads were as follows:
fuels thicket area snag area
tons/acre tonnes/ha tons/acre tonnes/ha
dead and down wood
0.0-0.25 inch (0.0-0.6 cm) 0.6 1.3 0.9 2.0
0.26-0.99 inch (0.61-2.5 cm) 2.1 4.6 2.9 6.4
1.0-3.0 inches (2.6-7.6 cm) 4.4 9.8 5.1 11.4
> 3.0 inches (7.6 cm) rotten 17.4 38.9 30.9 69.2
> 3.0 inches (7.6 cm) solid 17.0 38.1 50.1 112.2
litter 41.4 92.7 89.8 201.2
duff 32.5 72.8 30.0 67.1
Fire Management Considerations
fires. Following timber harvest, on sites where subalpine fir is not a
preferred species, light surface fires may be used to kill subalpine
fir and promote the establishment of other conifers .
Fuels remain moist in many high elevation subalpine fir habitat types
during most of the year, leaving only a short time period during certain
years when prescribed burning can take place [63,91].
Subalpine fir seeds germinate poorly in soils under burned slash piles
 but readily germinate on mineral soil seedbeds prepared by
broadcast burning [16,107].
Broad-scale Impacts of Plant Response to Fire
For further information on subalpine fir response to fire, see Fire Case Studies. Hamilton's Research Project Summary and Research Papers
(Hamilton 2006a, Hamilton 2006b)provide information on prescribed fire and
postfire response of plant community species, including subalpine fir,
that was not available when this species review was originally written.
Plant Response to Fire
Following fire, subalpine fir reestablishes via seeds dispersed by wind
from trees surviving in protected pockets or from trees adjacent to
burned areas. Subalpine fir readily establishes on burned mineral soil
seedbeds . Ash does not affect germination, but if it is deep, it
can prevent a seedling's roots from reaching mineral soil .
Although seedling establishment is often favored by shade, it will
establish in full sunlight following fire .
The rate of establishment is quite variable, and depends on the
proximity of the seed source (because the heavy seeds are dispersed over
short distances) and seed production during the year of the fire and
immediate postfire years. In general, subalpine fir seedling
establishment is very slow in areas suffering large, continuous crown
fires but is relatively rapid on small burned-over areas where a seed
source is nearby [90,124,128]. Three years after a late August wildfire
in northern Colorado, in a dense, mature stand composed of Engelmann
spruce, subalpine fir, and lodgepole pine, subalpine fir had established
15,200 seedlings per acre (37,500/ha) on small burns that were less than
one-tenth of an acre in size. But on areas within the middle of the
main burn, subalpine fir had established only 12 seedling per acre
(30/ha) 3 years after the fire . In Colorado, Peet  found a
75-year-old burn that had few conifer seedlings even though an
old-growth subalpine fir-Engelmann spruce stand was 218 yards (200 m)
Reinvasion into large burns is slow because much of the seed source is
destroyed. However, sometimes sporadic survivors provide a limited seed
source so that a small number of seedlings establish quickly following
fire. When this occurs, large quantities of seeds are dispersed several
decades later as the early invading seedlings mature and reach cone
bearing age .
On areas where subalpine fir is abundant and lodgepole pine scarce
before burning, subalpine fir establishes quickly following fire if
sufficient numbers of seed trees survive or are near the burn. However,
if lodgepole pine is present prior to burning, it usually seeds in
aggressively and assumes a dominant role because it quickly overtops any
fir seeding in at the same time . Subalpine fir can be suppressed
for several decades in seral lodgepole stands which develop following
fire; one-hundred-year-old individuals may be only 3 feet (0.9 m) tall
. It may take 50 to 150 years after a fire for substantial
subalpine fir establishment under dense lodgepole pine stands
In the Olympic Mountains, tree seedling establishment following fires in
closed mountain hemlock-subalpine fir forests was higher during wet
growing seasons than during dry growing seasons. Establishment rates
were higher near the edge of a fire or near survivors than in areas
removed from a seed source . On many burned areas, subalpine fir did
not establish seedlings for several years because of poor seed crops.
On some burns there was a lag time of 40 to 50 years after fire before
there was substantial seedling establishment. This was a result of
early invading trees maturing and dispersing seeds .
High elevation subalpine fir stands that have burned often remain open
for several decades or more [18,31]. The harsh environment near
treeline makes it difficult for tree seedlings to establish and survive
. Grasses and sedges may form a mat in subalpine meadows which
prevents tree seeds from reaching mineral soil .
Immediate Effect of Fire
Subalpine fir is one of the least fire-resistant western conifers. It
is very susceptible to fire because it has (1) thin bark that provides
little insulation for the cambium, (2) bark which ignites readily, (3)
shallow roots which are susceptible to soil heating, (4) low-growing
branches, (5) a tendency to grow in dense stands, (6) highly flammable
foliage, and (7) moderate to heavy lichen growth [37,111].
Subalpine fir forests are normally subject to highly destructive crown
fires that occur at 100-year or longer intervals. Such fires typically
kill all subalpine fir trees. Subalpine fir is also very susceptible to
surface fires because fine fuels which are often concentrated under
mature trees burn slowly and girdle the thin-barked bole .
crown-stored residual colonizer; short-viability seed in on-site cones
secondary colonizer; off-site seed carried to site after year 2
off-site colonizer; seed carried by wind; postfire years 1 and 2
Plant adaptations to fire: Subalpine fir is very fire sensitive and
generally suffers high mortality even from low intensity fires. It
relies on wind-dispersed seeds which readily germinate on fire-prepared
seedbeds to colonize burned areas. The occasional mature tree which
survives fire, those escaping fire in small, unburned pockets, and trees
adjacent to burned areas provide seeds to colonize burned sites. In
subalpine habitats, scattered subalpine fir trees often escape fire
because of discontinuous fuels, broken and rocky terrain, and the moist
and cool environment [78,87,91].
Fire regime: Subalpine fir habitat types vary from cold and wet at
higher elevations to warm and moist or cool and dry at lower elevations.
This environmental gradient influences the mean fire return interval
(MFRI). Relatively dry lower elevation subalpine fir habitat types have
more frequent and less intense fires than moist middle and upper
elevation subalpine fir habitat types [12,91]. Such forests in the
Bitterroot National Forest in Montana have a MFRI of 17 to 28 years
. Fires at this frequency kill subalpine fir and keep these forests
dominated by seral conifers such as lodgepole pine, Douglas-fir, or
western larch. Moist, middle and upper elevation subalpine fir habitat
types, however, generally experience high intensity stand-replacing
fires at intervals of 100 years or more. Mean fire return intervals for
middle and upper elevation subalpine fir habitat types in several areas
are presented below:
Location Community dominants MFRI Reference
Kananaskis Park, AB subalpine fir, spruce, 90 
northern Cascades, WA subalpine fir 154 
northern Cascades, WA subalpine fir-lodgepole pine 109 
Olympic NP, WA subalpine fir 150 
Yellowstone NP, WY subalpine fir 300-350 
Coram Exp. Forest, nw MT western larch, Douglas-fir, 117-146 
lodgepole pine, subalpine fir
Fuels and fire behavior: The fuel structure in subalpine-fir-dominated
stands promotes highly destructive stand-destroying fires. Fuel loads
in subalpine fir stands are greater than in lower elevation montane
stands because the cool and moist environment slows the decomposition of
organic matter allowing fuels to accumulate more rapidly . Fuel beds
tend to be irregular, with over twice as much fuel accumulating under
the narrow-crowned trees as between them . The needles are small
and fine and form a compact fuel bed in which fire spreads slowly .
These concentrated, slow burning fuels frequently produce flames high
enough to reach subalpine fir's low-growing dead branches . Thus
crowning is common in subalpine fir stands.
Once a crown fire begins, it spreads easily because subalpine fir has a
tendency to grow in dense stands and has highly flammable foliage. A
lightning strike on May 7, 1987, in a subalpine fir-mountain hemlock
stand in Mount Rainier National Park started a crown fire even though
the ground was still partially snow covered. The fire spread slowly
through the tree crowns by (1) igniting lichens draped along the fine
branches, (2) preheating and igniting the foliage, and (3) spreading to
a nearby tree by igniting its lichens .
More info for the terms: climax, severity, succession
In the Rocky Mountains, subalpine fir is a shade-tolerant climax species
favored by long fire-free intervals. Its seedlings outcompete spruces,
lodgepole pine, and Douglas-fir when light intensities are less than 50
percent of full sunlight, but cannot compete with these conifers under
brighter light . In Montana and Idaho and in the mountains of
eastern Washington and eastern Oregon, subalpine fir often forms pure
stands at climax, but it may also mix with Engelmann spruce, which,
although considered to be seral to subalpine fir, outlives it and
persists to climax. In the Rocky Mountains north and south of Montana
and Idaho, Engelmann spruce and subalpine fir may codominate at climax
Throughout much of the Cascade Mountains subalpine fir grows as a
shade-intolerant, seral species and is gradually replaced by more
shade-tolerant associates such as Pacific silver fir, grand fir, and
mountain hemlock . It often invades recently disturbed areas with
lodgepole pine. It also pioneers harsh sites on raw geologically young
surfaces such as lava flows and talus slopes and on climatically harsh
sites near timberline .
In areas where subalpine fir is a climax dominant, succession following
disturbance varies depending upon the severity and type of disturbance,
elevation, and the availability of conifer seeds. Subalpine fir may
establish immediately following disturbances if mature trees survive to
provide seeds and seral species such as lodgepole pine and aspen are
scarce. Near treeline, it may take 100 years or more for subalpine fir
to establish seedlings following fire because an increase in herbaceous
species prevents seeds from reaching mineral soil and the harsh climate
kills many seedlings that do establish [18,109]. Aspen and lodgepole
pine are the most common seral species. They often form pure stands and
completely dominate low and middle elevation stands within the subalpine
fir zone following large fires [5,68]. These species grow rapidly and
quickly overtop any subalpine fir seedlings that may establish at the
same time. Aspen stands can sometimes persist for decades or even
centuries when conifer seed trees are eliminated . When lodgepole
pine establishes immediately following stand-destroying fires, it often
forms even-aged dense stands that dominate for 100 to 300 years.
Because it is very shade tolerant, subalpine fir eventually establishes
under the pine canopy, usually within 100 years, and attains dominance
as the pine stand begins to break up [90,98].
In many of the warmer and lower elevation subalpine fir habitat types,
subalpine fir has not achieved climax dominance because of repeated
fires which favor shade-intolerant seral conifers. Many of these
habitat types are in midsuccessional stages. Lodgepole pine, western
larch, western white pine, or Douglas-fir dominate the overstory, but
subalpine fir seedlings and saplings occur in the understory [93,113].
Cone and seed production: Subalpine fir can begin producing cones when
20 years old and 4 or 5 feet (1.2-1.5 m) tall, but under closed forest
conditions seed production is generally not significant until trees are
older and taller . Corkbark fir generally does not produce cones
until about 50 years old . Nearly all cones are produced on the
uppermost part of the crown. Maximum seed production is by dominant
trees between 150 and 200 years old . Yearly seed production is
very erratic; good seed crops are produced every 3 to 5 years, with
light crops or crop failures in between [39,40,54,86]. Corkbark fir is
also a poor seed producer, having more crop failure years than good seed
crop years . Subalpine fir averages 34,800 seeds per pound
(76,700/kg), while corkbark fir seeds average 22,300 per pound
Seed predation: Insect pests reduce seed yields by feeding on cones and
seeds; however, the magnitude of loss is variable . Red squirrels
cut and cache large quantities of subalpine fir cones . After
dispersal, numerous small rodents and birds consume seeds from the
Dispersal: Mature subalpine and corkbark fir seeds have a large wing
and are dispersed primarily by wind in the fall as cones disintegrate on
the tree. Seeds travel primarily in the direction of prevailing winds,
but upslope drafts can influence dispersal at low and middle elevations
. Studies in Colorado showed that about one-half of subalpine fir
seeds dispersed into clearcuts fell within 100 feet (30 m) of the
clearcut's windward edge, while the remainder fell within 260 feet (80
m) of the edge . Some seeds are also dispersed by red squirrels
which cut and cache cones before they disintegrate; seeds commonly
germinate from these middens, forming thickets .
Germination and viability: Seeds overwinter under or in snow. This
cold, moist stratification is required for germination .
Germination begins in the spring a few days after snowmelt and is
usually completed within a few weeks [9,106]. Percent germination is
low due to unsound seed; about 31 to 38 percent for subalpine fir and 26
to 33 percent for corkbark fir [39,41]. Under natural conditions seeds
remain viable for 1 year . Stratification procedures for stored
seeds have been described in detail [41,74].
Seedling establishment and survival: Seedlings establish best on
mineral soil seedbeds but will also establish on other surfaces
including litter, duff, and decaying wood . Because Engelmann
spruce requires a mineral soil seedbed, subalpine fir seedlings usually
outnumber spruce seedlings in the understory of spruce-fir stands.
Thus, even though it is short-lived, many ecologists consider subalpine
fir better able to regenerate under climax conditions than Engelmann
spruce. Subalpine fir is very shade tolerant and easily establishes
under a closed canopy. Throughout the Rocky Mountains subalpine fir is
reproducing abundantly under conditions of dense shade and is often
abundant as seedlings and saplings in spruce-fir forests, even where
Engelmann spruce dominates the overstory [11,67].
At higher elevations, seedling survival is sometimes greater on duff
seedbeds because the duff helps protect seedlings from high-intensity
summer rain storms and frost heaving . At lower elevations,
seedling densities are often greater on mineral soils . In a
spruce-fir forest in southeastern Wyoming, Knapp and Smith  found
that 42 percent of subalpine fir seedlings were on litter deeper than 1
inch (2.5 cm), compared with only 5 percent of Engelmann spruce
seedlings. Subalpine fir is able to establish in duff because of its
rapid root growth. Comparing seedlings grown in a greenhouse, subalpine
fir's taproot length (29 mm) 2 weeks after germination was over 200
percent greater than the taproot length of Engelmann spruce (9.4 mm)
Growth: Subalpine fir seedlings grow very slowly. One-year-old
seedlings are frequently less than 1 inch (2.5 cm) tall . One study
found 15-year-old seedlings averaged only 11 inches (28 cm) in height on
burned-over slopes, 10 inches (25 cm) on cut-over dry slopes, and 6
inches (15 cm) on cut-over wet flats . Under favorable conditions
trees reach a height of 4 to 5 feet (1.2-1.5 m) in 20 to 40 years .
Under a closed canopy, trees 4 to 6 feet tall (1.2-1.8 m) are often 35
to 50 years old.
Vegetative reproduction: Near timberline subalpine fir frequently
reproduces by layering, probably as a result of heavy snow, wind, and
cold temperatures which restrict growth away from the ground. Layering
often results in clusters of subalpine fir growing near timberline .
Under closed forest canopy, reproduction by layering is negligible.
Growth Form (according to Raunkiær Life-form classification)
More info for the terms: phanerophyte, therophyte
Undisturbed State: Phanerophyte (mesophanerophyte)
Undisturbed State: Phanerophyte (microphanerophyte)
Undisturbed State: Phanerophyte (nanophanerophyte) Krummholz form
Burned or Clipped State: Therophyte
Reaction to Competition
Subalpine fir, together with Engelmann spruce, forms a climax or long-lived seral forest vegetation throughout much of its range. In the Rocky Mountains of British Columbia and Alberta and south of Montana and Idaho, subalpine fir and Engelmann spruce occur as either codominants or in pure stands of one or the other. Spruce, however, is most likely to form pure stands, especially at upper elevations. In the Rocky Mountains of Montana and Idaho and the mountains of eastern Oregon and Washington, subalpine fir is a major climax. Engelmann spruce may be either a major climax or a persistent long-lived seral. Pure stands of either species may occur, but subalpine fir is more likely to form pure stands, especially at high elevations (2).
Although subalpine fir is a dominant element in several climax or near-climax vegetation associations, these forests differ from the typical climax forest in that most of them are not truly all-aged. For example, in spruce-fir forests, some stands are single-storied while others are two-, three-, and multi-storied. Multi-storied stands may result from past disturbances such as fire, insect epidemics, or cutting, or they may result from the gradual deterioration of single- and two-storied stands associated with normal mortality from wind, insects, and diseases (5). On the other hand, some multi-storied stands appear to have originated as uneven-aged stands and are successfully perpetuating that structure (3,27).
Where subalpine fir is a component of the climax vegetation, the natural tendency is for subalpine fir to reestablish itself when destroyed and temporarily replaced by other vegetation (27). Throughout most of the Cascades and in the Rocky Mountains where subalpine fir grows with the other true firs and/or mountain hemlock, it is seral. Subalpine fir also is a pioneer on difficult sites, where its ability to reproduce by layering allows it to colonize more readily than its common associates (22).
The ecophysiology of subalpine fir in relation to common associated species is becoming better understood (33,34,35,36). What is known about the general water relations of subalpine fir can be summarized as follows: (1) needle water vapor conductance (directly proportional to stomatal opening) is controlled primarily by visible irradiance and absolute humidity difference from needle to air (evaporative demand) with secondary effects from temperature and water stress; (2) nighttime minimum temperatures below 3.9° C (39° F) retard stomatal opening the next day; (3) stomata function well from early spring to late fall, and high transpiration rates occur even with considerable snowpack on the ground; (4) leaf water vapor conductance is lower than that of Engelmann spruce, lodgepole pine, and aspen, the common associates of central Rocky Mountain subalpine forests; (5) subalpine fir trees have a larger total needle area per unit of sapwood water-conducting tissue than the other three species; and (6) subalpine fir trees have a slightly lower needle area per unit of bole or stand basal area than Engelmann spruce, but greater than lodgepole pine or aspen. At equal basal area, annual canopy transpiration of subalpine fir is about 35 percent lower than spruce, but 15 percent higher than lodgepole pine, and 100 percent higher than aspen. These high rates of transpiration cause subalpine fir to occur primarily on wet sites, generally in association with Engelmann spruce (37,38).
Both even- and uneven-aged silvicultural. systems can be used in stands where subalpine fir is a component (1,5,8). The appropriate even-aged cutting methods are clearcutting and shelterwood cutting and their modifications. The seed-tree method cannot be used because of susceptibility of subalpine fir to windthrow. The uneven-aged cutting methods are individual tree and group selection and their modifications. In spruce-fir stands, shelterwood and individual-tree- selection methods will favor subalpine fir over Engelmann spruce, lodgepole pine, and interior Douglas-fir (4). In stands where subalpine fir grows with Pacific silver fir, grand fir, and/or mountain hemlock, clearcutting and group shelterwood or group selection cutting will favor subalpine fir (22).
Life History and Behavior
More info for the term: phenology
Subalpine fir requires 2 years to complete its reproductive cycle .
Cones are initiated in the spring of the first year as microscopic
primordia within vegetative buds. Bud differentiation occurs in
midsummer, and separate seed-cone and pollen-cone buds develop until
each becomes dormant in the fall . During the spring of the second
year, cone buds resume growth and conelets are recognizable in the early
spring. During the second year, reproduction phenology generally
proceeds as follows:
Phenological event Location Timing of event Reference
flowering sw MT, nw WY mid-June - early July
cones full size " late August
seeds dispersed " early Sept - early Oct [41,101]
flowering nw MT, n ID mid-June - early July
cones full size " late July - early Aug
seeds dispersed " mid-Sept [41,101]
flowering OR late May - early July
seed dispersal " early Oct 
male bud burst Linn, OR early to mid-May
female bud burst " mid to late May
pollen shed " June
seed dispersal begins " early October 
flowering AZ, San Fran.Peaks late June
cone ripening " mid-Sept - early Oct
seed dispersal " late Sept - early Oct 
Although subalpine fir grows under nearly all light intensities found in nature, establishment and early survival are usually favored by shade. In the absence of Pacific silver fir, grand fir, and mountain hemlock, subalpine fir will survive under closed-forest conditions with less light than Engelmann spruce, noble fir, and white spruce (22). When grown with Pacific silver and grand fir, and/or mountain hemlock, subalpine fir does not compete successfully under closed-forest conditions. It does not compete well with the spruces, lodgepole pine, or interior Douglas-fir when light intensity exceeds 50 percent of full shade (9).
Subalpine fir is restricted to cold, humid habitats because of low tolerance to high temperatures. Newly germinated subalpine fir seedlings tolerate high solar radiation, but they are susceptible to heat girdling and drought. Seedlings are also killed or damaged by spring frosts, competing vegetation, frost heaving, damping off, snowmold, birds, rodents, and trampling and browsing by large animals, but losses are not different than for any common associate (5).
The number of seeds required to produce a first-year seedling, and an established seedling (at least 3 years old), and the number of first-year seedlings that produce an established seedling vary considerably, depending upon seed production, distance from source, seedbed, and other environmental conditions. In one study in Colorado, covering the period 1961 to 1975 and a wide variety of conditions, an average of 150 seeds (range 35 to 290) was required to produce a first-year seedling. An average of 755 seeds (range 483 to 1,016) was required to produce a 4- to 13-year-old established seedling. For every established 4- to 13-year-old seedling, an average of 10 first-year seedlings were required, with a range of as few as 4 to as many as 14 (50).
Early root growth of subalpine fir is very slow. The root length of first-year seedlings in one study in British Columbia averaged only 6.8 cm (2.7 in) (20). No comparable data are available in the United States, but first-year penetration of corkbark fir in Arizona averaged 8.6 cm (3.4 in) (32).
Shoot growth is equally slow at high elevations. Many first-year seedlings are less than 2.5 cm (I in) tall. Annual height growth of seedlings during the first 10-15 years usually averages less than 2.5 cm (1 in).
In one study, seedlings 15 years old averaged only 28 cm (11 in) in height on burned-over slopes, 25 cm (10 in) on cutover, dry slopes, and 15 cm (6 in) on cutover, wet flats (30). In another study, seedlings grown on mineral soil averaged only 58.8 cm (24 in) after 21 years (28). Trees reach 1.2 to 1.5 m (4 to 5 ft) in height in 20 to 40 years under favorable environmental conditions. However, trees less than 13 cm (5 in) in diameter are often 100 or more years old at higher elevations, and trees 1.2 to 1.8 m (4 to 6 ft) high and 35 to 50 years old are common under closed-forest conditions (40,51).
At lower elevations, seedling shoot growth has been better. In one study in the Intermountain West, average annual height growth of subalpine fir seedlings for the first 10 years after release was 11.4 cm (4.5 in) on clearcuts and 8.1 cm (3.2 in) on partial cuts (48).
Seed Production and Dissemination
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 (24,42). It is as good a seed producer as most associated true firs, but not as good as the hemlocks and Engelmann spruce. In one 11-year study at four locations in the Cascades, subalpine fir cone crops, based on the following criteria, were rated medium to very heavy in 6 years and very light to failure in the other 5 (24).
Number of cones/tree Crop rating 0 Failure 1-9 Very Light 10-19 Light 20-49 Medium 50-99 Heavy 100+ Very heavy In the Rocky Mountains south of Idaho and Montana, seed production of subalpine and corkbark fir has generally been poor, with more failures than good seed years. In one study in Colorado covering 42 area-seed-crop years, subalpine fir was an infrequent seed producer. Some seed was produced in only 8 of the years, while the other 34 were complete failures (50). Similar results have been obtained from other seed-production studies in Colorado. However, because these studies were designed to sample seed production in spruce-fir stands and because Engelmann spruce made up 90 percent or more of the dominant stand basal area, these results only indicate subalpine fir seed production in spruce-fir stands, not of individual dominant fir trees (9).
A number of cone and seed insects of subalpine fir have been identified but their relative importance, frequency of occurrence, and the magnitude of losses are not known (39). Some seed is lost from cutting and storing of cones by pine squirrels (Tamiasciurus hudsonicus fremonti), and, after seed is shed, small mammals, such as deer mice (Clethrionomys gapperi), mountain voles (Microtus montanus), and western chipmunks (Eutamias minimus), consume some seeds (5). However, the amount of seed lost to mammals, birds, and other causes are not known.
Cones disintegrate when they are ripe. Scales fall away with the large, winged seeds, leaving only a central, spikelike axis. Dissemination beginning in September usually is completed by the end of October in the Rocky Mountains. In the Pacific Northwest, seed dissemination begins in October and usually continues into November, but pitched-up cones may extend dissemination into December. Nearly all seed is dispersed by the wind (21,60).
Subalpine fir seeds are fairly large, averaging 76,720/kg (34,800/lb). Little information is available on seed dispersal distances. Studies designed to measure Engelmann spruce seed dispersal show similar dispersal patterns for subalpine fir. Prevailing winds influence the dispersal pattern, with about half the seeds falling into openings within 30 m (100 ft) of the windward timber edge. Seedfall continues to diminish until about two-thirds the way across the opening, and then levels off before slightly increasing about 15 m (50 ft) from the leeward timber edge (50). Thermal upslope winds are important in seed dispersal in mountainous terrain at mid- to lower-elevations (54).
Subalpine fir seed viability is only fair: average germinative capacity is 34 percent and vitality transient (60). Observations and limited studies in the Rocky Mountains indicate that germinative capacity is often less than 30 percent (55). Some lots of stored seeds exhibit embryo dormancy, which can be broken by stratification in moist sand or peat at 5° C (41° F) for 60 days (9,60).
Flowering and Fruiting
Growth and Yield
Growth is not rapid; trees 25 to 51 cm (10 to 20 in) in diameter are often 150 to 200 years old under closed-forest conditions. Trees older than 250 years are not uncommon. But, because the species suffers severely from heartrot, many trees either die or are complete culls at an early age. Few data are available on the yields of subalpine fir in natural stands. It usually grows in mixed stands and comprises only a minor part of the volume. In the Rocky Mountains and Pacific Northwest, where it grows in association with Engelmann spruce, subalpine fir usually makes up only 10 to 20 percent of the saw log volume, which may range from less than 12,350 to more than 98,800 fbm/ha (5,000 to 40,000 fbm/acre) (30,49). In the Pacific Northwest and Rocky Mountains, where subalpine fir grows with other true firs and/or mountain hemlock, few trees reach minimum merchantable size before being crowded out of the stand (22). Subalpine fir in the Rocky Mountains grows in pure stands most often on sites so severe that it has little commercial value. In the Pacific Northwest, pure stands on commercial sites typically occur on southerly slopes and are usually less than 150 years old. These stands are not extensive but are distinctive (21).
Molecular Biology and Genetics
Races and Hybrids Corkbark fir is the only recognized natural geographical variety of subalpine fir (43). Like many species with wide distribution, it has probably developed unknown races and hybrids, and there is some evidence that natural introgressive hybridization between subalpine and balsam fir occurs where they grow together in Canada. Horticultural and ornamental cultures have been recognized (45). These include:
1. Abies lasiocarpa cv beissneri a dwarf tree bearing distorted branches and twisted needles. 2. A. 1. cv coerulescens a beautiful tree with specially intensive bluish needles. 3. A. 1. cv compacta. A dwarf tree of compact habit.
Barcode data: Abies lasiocarpa
Statistics of barcoding coverage: Abies lasiocarpa
Public Records: 4
Specimens with Barcodes: 4
Species With Barcodes: 1
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N5 - Secure
Rounded National Status Rank: N5 - Secure
NatureServe Conservation Status
Rounded Global Status Rank: G5 - Secure
Reasons: Common and widespread in mountainous Western North America.
Please consult the PLANTS Web site and your State
Department of Natural Resources for this plant’s current status, such as, state noxious status and wetland indicator values.
Timber harvest: Shelterwood and individual tree selection silvicultural
methods favor subalpine fir over Engelmann spruce, lodgepole pine (Pinus
contorta), and Douglas-fir (Pseudotsuga menziesii); clearcutting and
group selection cutting favor subalpine fir over Pacific silver fir
(Abies amabilis), grand fir (A. grandis), and mountain hemlock (Tsuga
mertensiana) where they grow together . The seed tree method is
generally not used because of the susceptibility of subalpine fir to
windthrow . In the Rocky Mountains, clearcutting and shelterwood
cutting have been the most commonly used harvesting methods in
old-growth Engelmann spruce-subalpine fir stands because these stands
tend to be even-aged and overmature . Uneven-aged silviculture can
pose a problem because residual subalpine fir trees damaged during
thinning operations are susceptible to attack by decay fungi.
Silvicultural systems and cutting methods for managing subalpine fir
have been discussed in detail [7,8,9,11].
Pests and diseases: Subalpine fir is attacked by numerous insects. The
most destructive seem to be the western spruce budworm, western balsam
bark beetle, and balsam woolly aphid . Subalpine fir is one of the
most common hosts of the western spruce budworm. This pest generally
attacks low and middle elevation subalpine fir forests but is largely
absent from high elevation forests . The balsam woolly aphid has
virtually eliminated subalpine fir from some stands in the Cascades
. Other insect pests include the Douglas-fir tussock moth, western
black-headed budworm, and fir engraver beetle.
Subalpine fir is susceptible to annosus root disease, caused by the
fungus Heterobasidion annosum, which results in root and butt decay.
Outbreaks of this disease are often centered around large 20-year-old or
older fir stumps that contain the fungus' fruiting bodies .
Subalpine fir is most seriously affected by this disease in the northern
and central Rocky Mountains , and is affected to a lesser extent in
the Pacific Northwest . Subalpine fir is susceptible to several
other wood rotting fungi that cause heart, trunk, butt, or root rots,
including brown stringy rot, red heart rot, red ring rot, shoestring
rot, brown cubical rot, white spongy root rot, and white pocket rot
. Trees weakened by wood rots often become infested by fir engraver
beetles and usually succumb to windfall and breakage . Fir broom
rust is another common problem in Engelmann spruce-subalpine fir stands
and causes bole deformation, spike tops and wind breakage, and makes
trees more susceptible to decay fungi .
Habitat for threatened and endangered species: Old-growth subalpine fir
stands in northern Idaho may provide critical habitat for woodland
caribou . Numerous subalpine fir habitat types, especially those
containing huckleberries (Vaccinium spp.), provide critical habitat for
grizzly bears .
Cultivars, improved and selected materials (and area of origin)
Available through most nurseries. Horticultural and ornamental cultures have been recognized, including the following:
A. lasiocarpa cv. beissneri – a dwarf tree bearing distorted branches and twisted needles.
A. lasiocarpa cv. caerulescens – a normal-sized tree with especially intensive bluish needles.
A. lasiocarpa cv. compacta – a dwarf tree of compact habit.
Periodic thinning increases the yield and size of individual trees, but the fir component of subalpine spruce-fir stands is likely to be greatly reduced by repeated thinning, so that the stand at the time of final harvest will be almost pure Spruce.
In the Cascades, the European balsam woolly adelgid has caused significant mortality to subalpine fir, virtually eliminating it from some stands in Oregon and southern Washington. Windthrow is a common problem in subalpine fir, presumably because of its relatively shallow root system. Pruning should be kept to a minimum, for when older branches are removed, new growth seldom develops and, consequently, the trees become ragged and unkempt.
Relevance to Humans and Ecosystems
Value for rehabilitation of disturbed sites
Subalpine fir can be planted on disturbed sites within forest vegetation
types where it naturally occurs . It is generally recommended for
cool and moist sites within subalpine areas . Its erosion control
potential is listed as medium in Utah and Montana, and high in Colorado
. Because this wide-ranging tree exhibits a large degree of genetic
variation, seed or nursery stock for rehabilitation projects should come
from a local source. Transplanting nursery stock is generally more
successful than direct seeding . Seedlings exhibit very slow
initial growth and are therefore usually outplanted as 2- to 3-year-old
seedlings . Wild seedlings may also be transplanted . A
maximum spacing of 10 x 10 feet (3 x 3 m) has been recommended for
seedlings or transplants . Methods for collecting, processing,
testing, storing, and planting subalpine fir seeds have been discussed
in detail [32,41].
Big game: Subalpine fir habitat types provide excellent hiding cover
for deer, elk, mountain goats, moose, and bear [10,113]. Certain low
elevation subalpine fir forests may be used by elk during calving, and
high elevation subalpine fir forests by bighorn sheep during lambing and
lamb rearing . Dense stands provide cool summertime shade for big
game animals . In Yellowstone National Park, grizzly bear daybeds
are often found in subalpine fir stands .
Small mammals and birds: Small subalpine firs provide good year-round
hiding cover. Dense thickets of small trees are often nearly
impenetrable and provide hiding places for small mammals such as
snowshoe hares and porcupines [13,71]. Blue grouse often overwinter in
subalpine trees and rely almost exclusively on them for escape cover
. Subalpine fir snags are used by numerous cavity-nesting birds,
but are generally less preferred than those of associated conifers
The degree to which subalpine fir provides environmental protection
during one or more seasons for wildlife species is as follows :
CO MT WY UT
Pronghorn ---- ---- poor poor
Elk good fair good good
Mule deer good fair good good
White-tailed deer ---- ---- poor ----
Small mammals good good good good
Small nongame birds good fair good good
Upland game birds good good good fair
Waterfowl ---- ---- poor poor
Percent composition of subalpine fir browse collected near Jackson Hole,
Wyoming, was as follows :
date crude ether crude nitrogen
collected protein extract fiber free extract
11/25 5.57 7.53 20.19 50.26
A study in Montana found the following concentration of elements in
subalpine fir needles and twigs :
1-yr-old green needles twigs < 0.25 inch (0.64 cm) in diameter
(micrograms/gram [mean]) (micrograms/gram [mean])
Ca 9722 5840
Cu 7.4 7.9
Fe 64 182
K 5553 7031
Mg 819 1038
Mn 1020 587
N 10690 4962
Na 103 124
P 1450 2254
Zn 43 5
(percent [mean]) (percent [mean])
Ash 3.5 3.5
Its palatability to big game animals is generally low also, but in some
locations it is highly palatable to moose and mountain goats during
winter and spring [89,99]. The seeds are palatable to numerous small
mammal species . Red squirrels generally eat subalpine fir seeds
after other cached conifer seeds have been consumed . The needles
are highly palatable to blue grouse.
The relish and degree of use shown by livestock and wildlife species for
subalpine fir in several western states is rated as follows
CO MT WY UT ID
Cattle poor poor poor poor ----
Sheep poor poor poor poor ----
Horses poor poor poor poor ----
Pronghorn ---- ---- poor poor ----
Elk ---- poor poor poor ----
Moose ---- good good ---- fair
Mule deer ---- poor poor poor ----
White-tailed deer ---- ---- poor ---- ----
Small mammals ---- fair fair good ----
Small nongame birds ---- ---- fair good ----
Upland game birds ---- fair fair good ----
Waterfowl ---- ---- poor poor ----
Importance to Livestock and Wildlife
Subalpine-fir-dominated stands generally do not produce enough forage
for livestock but do provide browse and cover for large and small
wildlife species. Mule deer, elk, moose, woodland caribou, black bear,
and grizzly bear often use subalpine fir habitats as summer range
[10,23,113]]. Subalpine fir forests are generally not suitable winter
range for deer and elk because of heavy snowpack, but some lower
elevation subalpine fir habitat types are used by moose and woodland
caribou during the winter [23,61,89]. Subalpine fir forests support
numerous species of small mammals and birds. The snowshoe hare, flying
squirrel, red squirrel, porcupine, pine marten, fisher, lynx, and
several species of mice, voles, chipmunks, and shrews all inhabit
subalpine fir forests [26,104,113]. Numerous species of birds nest and
feed in subalpine fir forests, including several woodpeckers,
flycatchers, kinglets, nuthatches, juncos, thrushes, chickadees,
crossbills, the pine siskin, owls, and grouse [104,113].
The young growth of subalpine fir is sometimes eaten by mule deer, elk,
bighorn sheep, and snowshoe hares, but it is not an important food item.
Subalpine fir comprises only a small portion of the summer diet of
mountain goats but can be a major food source in the winter and spring
. Throughout much of Montana, Idaho, and Wyoming, subalpine fir is
an important winter food of moose . On moose winter range near
Jackson Hole, Wyoming, an average of 13 to 18 percent of small subalpine
fir trees were browsed by moose, and 44 to 78 percent of the branches on
trees browsed were utilized . In Yellowstone National Park, grizzly
bears sometimes strip the bark of subalpine fir to feed on the
underlying cambium . The winter diet of blue grouse consists
primarily of conifer needles. These grouse often winter in subalpine
stands and may feed heavily on the needles and buds of subalpine fir
Subalpine fir seeds are eaten by several species of small mammals and
birds. Red squirrels eat seeds from cached subalpine fir cones .
Fir seeds are also eaten by chipmunks and mice. Several birds,
including chickadees, nuthatches, crossbills, the pine siskin, and the
Clark's nutcracker remove and eat the seeds from fir cones [49,77].
Because subalpine fir seeds are large, comprising about 26 percent of a
cone's weight, they are an energy-efficient food source for small birds
. Small birds may make considerable use of fir seeds, but their
foraging is scattered and sporadic throughout subalpine forests .
Wood Products Value
and compressive strength . It is easy to work, glues well, and
holds nails and screws fairly well. The wood is primarily used for
products such as lumber for home construction and for prefabricated wood
products . Subalpine fir has excellent pulping properties . Use
for poles and pilings requires large amounts of preservatives because
the wood decays rapidly .
Other uses and values
screenings or windbreaks . In the Pacific Northwest it is
sometimes transplanted into rock gardens or simulated subalpine settings
Native Americans used various parts of subalpine fir for numerous
purposes. A hair tonic was prepared by mixing powdered needles with
deer grease. Finely ground needles were also sprinkled on open cuts.
Sticky resin collected from the bark was boiled and used as an
antiseptic for wounds or as a tea for colds. Boughs were placed in
rooms for their aroma, and pulverized needles were used as a body scent
or as perfume for clothing .
Resin from the bark is used in the optical industry and in laboratories
as a cement for lenses and microscope slides .
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 (1,5).
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, sulfite, or groundwood processes (59).
The wood is white, soft, brittle, and quick to decay, used for rough construction and boxes, doors, frames, poles, and fuel. Small trees are extensively used for Christmas trees. Subalpine fir is a forest pioneer on severe and disturbed sites. By providing cover, it assists in rehabilitating the landscape and protecting watersheds. Subalpine fir grows in forests that occupy the highest water yield areas in much of the western United States and are thus highly significant in water management and conservation.
Native Americans used pitch and bark preparations for wounds and the wood, bark, and boughs for roof shingles, baskets and bedding. The pitch was also used to coat canoe seams and rubbed on bowstrings as a sealant and protectant.
Abies lasiocarpa is native to the mountains of Yukon, British Columbia and western Alberta in Western Canada; and to southeastern Alaska, Washington, Oregon, Idaho, western Montana, Wyoming, Utah, Colorado, New Mexico, Arizona, northeastern Nevada, and the Trinity Alps of the Klamath Mountains in northwestern California in the Western United States.
It occurs at high altitudes, from 300–900 metres (980–2,950 ft) in the north of the range (rarely down to sea level in the far north), to 2,400–3,650 metres (7,870–11,980 ft) in the south of the range; it is commonly found at and immediately below the tree line.
It is a medium-sized tree growing to 20 metres (66 ft) tall, exceptionally to 40–50 metres (130–160 ft) 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 centimetres (0.59–1.18 in) 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 centimetres (2.4–4.7 in) 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. The cultivar 'Compacta' has gained the Royal Horticultural Society's Award of Garden Merit.
- Farjon, A. (2013). "Abies lasiocarpa". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 3 May 2014.
- RHS Plant Selector Abies lasiocarpa var. arizonica 'Compacta' Hornibr. AGM / RHS Gardening
- Hunn, Eugene S. (1990). Nch'i-Wana, "The Big River": Mid-Columbia Indians and Their Land. University of Washington Press. p. 351. ISBN 0-295-97119-3.
The only unique populations in this species come from coastal Alaska (A. S. Harris 1965; C. J. Heusser 1954). They are found at lower elevations (0--900 m) and appear to be isolated with no reported introgression between them and the coastal mountain populations. The population on the Prince of Wales Island has distinct terpene patterns and needs morphological and developmental studies to see if these patterns contrast with neighboring populations.
Through central British Columbia and northern Washington, Abies lasiocarpa introgresses with A . bifolia . These trees may have morphologic features resembling either species and may have intermediate terpene patterns; they are best classified as interior subalpine fir ( A . bifolia ´ lasiocarpa ). At the southern end of its range, A . lasiocarpa possibly hybridizes with A . procera (R.S. Hunt and E.von Rudloff 1979). Abies lasiocarpa shares with A . procera a red periderm, crystals in the ray parenchyma (R.W. Kennedy et al. 1968), and reflexed tips of the bracts, features not shared with A . bifolia .
Abies lasiocarpa usually exists in small stands at high elevations and is not often observed. Its differences in comparison to A . bifolia have prompted studies (W.H. Parker et al. 1979) to see if it is A . bifolia introgressed with the sympatric A . amabilis . Abies lasiocarpa and A . amabilis , however, are separated by many morphologic features, and no hybrids have been found (W.H. Parker et al. 1979).
Names and Taxonomy
Comments: Following Kartesz (1994 checklist and 1999 floristic synthesis), both the Rocky Mountain and Pacific Northwest components are included here in a single species. The Flora of North America (vol. 2, 1993) considers A. bifolia of the Rocky Mountain region to be a separate species. Kartesz (1994 and 1999) recognizes var. arizonica in Ariz., N.Mex., and Colo.; this includes some but not all of the plants treated by FNA as A. bifolia. LEM 17May95, rev. 28Oct01 LEM.
the northern hemisphere. Nine species of Abies, including subalpine
fir, are native to the United States . The currently accepted
scientific name of subalpine fir is Abies lasiocarpa (Hook.) Nutt.
. Subalpine fir is widely distributed and exhibits geographic
variation. Two varieties are recognized based on morphological
Abies lasiocarpa var. arizonica - corkbark fir
Abies lasiocarpa var. lasiocarpa - subalpine fir
Subalpine fir hybridizes with balsam fir (A. balsamea) where their
ranges overlap in the Canadian Rockies .
western balsam fir
Rocky Mountain fir
pino real blanco
Abies balsamea var. fallax (Engelm.) Boivin