Pinaceae -- Pine family

    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).

     AK  AZ  CO  ID  MT  NV  NM  OR  UT  WA
     WY  AB  BC  YT

Subalpine fir is the mostly widely distributed fir in North America,
spanning more than 32 degrees of latitude [11].  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 [11].  It occurs on both slopes of the Cascade Mountains
as far south as southern Oregon [11].  The two varieties are distributed
as follows [11,75]:

var. lasiocarpa - almost the same as the species, but not in central and
southeastern Arizona. 

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 [11].

More info on this topic.

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

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 (219). It is also found locally in northeastern Nevada and  northwestern California (43). Except where noted above, subalpine fir is a  major component of high elevation Pacific Northwest forests.

    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.

Abies lasiocarpa (Hook.) Nutt.:
Canada (North America)
United States (North America)

Note: This information is based on publications available through Tropicos and may not represent the entire distribution. Tropicos does not categorize distributions as native or non-native.

B.C., Yukon; Alaska, Calif., Oreg., Wash.

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

Global Range: Southeastern Alaska, western Canada, south to Oregon, Arizona, and New Mexico.

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.

Trees to 20m; trunk to 0.8m diam.; crown spirelike. Bark gray, thin, smooth, furrowed in age. Branches stiff, straight; twigs opposite to whorled, greenish gray to light brown, bark splitting as early as 2 years to reveal red-brown layer, somewhat pubescent; fresh leaf scars with red periderm. Buds hidden by leaves or exposed, tan to dark brown, nearly globose, small, resinous, apex rounded; basal scales short, broad, equilaterally triangular, glabrous or with a few trichomes at base, not resinous, margins crenate to dentate, apex sharp-pointed. Leaves 1.8--3.1cm ´ 1.5--2mm, spiraled, turned upward, flexible; cross section flat, prominently grooved adaxially; odor sharp (ß-phellandrene); abaxial surface with 4--5 stomatal rows on each side of midrib; adaxial surface bluish green, very glaucous, with 4--6 stomatal rows at midleaf, rows usually continuous to leaf base; apex prominently or weakly notched to rounded; resin canals large, ± median, away from margins and midway between abaxial and adaxial epidermal layers. Pollen cones at pollination ± purple to purplish green. Seed cones cylindric, 6--12 ´ 2--4cm, dark purple, sessile, apex rounded; scales ca. 1.5 ´ 1.7cm, densely pubescent; bracts included (specimens with exserted, reflexed bracts are insect infested). Seeds 6 ´ 2mm, body brown; wing about 1.5 times as long as body, light brown; cotyledon number 4--5. 2 n =24.

More info for the terms: monoecious, tree

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
tree's height.

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
areas.

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) [39].  Trees up to 130
feet (40 m) tall and 30 inches (76 cm) in diameter have been found but
are rare [39].  Subalpine fir grows very slowly; 150- to 200-year-old
trees are usually only 10 to 20 inches (25-50 cm) in diameter [39].
Trees seldom live more than 250 years because they are very susceptible
to heart rots [9].

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 [9].
Corkbark fir is generally recognized by its creamy-white, thick, corky
bark [25].  The root system generally is shallow but under favorable
conditions may develop relatively deep laterals [9].

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 [39].

Tree, Evergreen, Monoecious, Habit erect, Trees without or rarely having knees, Primary plant stem smooth, Tree with bark smooth, Tree with bark rough or scaly, Young shoots 3-dimensional, Buds resinous, Leaves needle-like, Leaves alternate, Needle-like leaf margins entire (use magnification), Leaf apex obtuse, Leaf apex mucronulate, Leaves < 5 cm long, Leaves < 10 cm long, Leaves blue-green, Leaves not blue-green, Leaves white-striped, Needle-like leaves flat, Needle-like leaves not twisted, Needle-like leaf habit erect, Needle-like leaf habit drooping, Needle-like leaves per fascicle mostly 1, Needle-like leaf sheath early deciduous, Needle-like leaf sheath persistent, Twigs pubescent, Twigs not viscid, Twigs without peg-like projections or large fascicles after needles fall, Berry-like cones orange, Woody seed cones > 5 cm long, Bracts of seed cone included, Seeds brown, Seeds winged, Seeds unequally winged, Seed wings prominent, Seed wings equal to or broader than body.

Pinus lasiocarpa Hooker, Fl. Bor.-Amer. 2: 163. 1838

More info for the terms: association, climax

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
[23,91].

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 [9].  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 [9].  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 [39]:

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
                                  (Thuja plicata)
                       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,
                                  lodgepole pine 
                       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
differing sites.

Elevation:  Alexander and others [11] 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
m).

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).

More info for the terms: climax, codominant, series

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
types.

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
        Apache, Gila,
          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
    Gunnison &
      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
      Cloud, Boulder,
      & 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
    Eagle Cap
      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

          

More info on this topic.

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):

   FRES20  Douglas-fir
   FRES22  Western white pine
   FRES23  Fir - spruce
   FRES24  Hemlock - Sitka spruce
   FRES25  Larch
   FRES26  Lodgepole pine
   FRES44  Alpine

More info on this topic.

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
   217  Aspen
   218  Lodgepole pine
   219  Limber pine
   223  Sitka spruce
   224  Western hemlock
   226  Coastal true fir - hemlock
   253  Black spruce - white spruce

More info on this topic.

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

Information on soils where subalpine fir grows is limited. In the  Pacific Coast region, soil parent materials are mixed and varied. Zonal  soils in the subalpine fir zone are Cryorthods (Podzolic soils), or  Haplorthods (Brown Podzolic soils) with well developed but ultimately thin  humus layers. Haploxerults and Haplohumults (Reddish-Brown Lateritic  soils), developed from volcanic lava; Xerochrepts (Regosolic soils),  developed from shallow residual material; and Lithic (Lithosolic soils)  are also common in some localities. Dystrandepts (Bog soils) and  Haplaquepts (Humic Gley soils) occur on poorly drained sites. Soils are  more acid than in lower elevation forests, with pH typically ranging from  4.5 to 5.9 (22,61).

    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).

Subalpine fir grows in the coolest and wettest forested continental area  of western United States (58). Temperatures range from below -45° C  (-50° F) in the winter to more than 32.2° C (90° F) in the  summer. Although widely distributed, subalpine fir grows within a narrow  range of mean temperatures. Mean annual temperatures vary from -3.9°  C (25° F) to 4.4° C (40° F), with a July mean of 7.2°  C to 15.6° C (45° F to 60° F), and a January mean of -15.0°  C to -3.9° C (5° F to 25° F) (10,26,47) (table 1). Average  precipitation exceeds 61 cm (24 in), much of which falls as snow. More  than half the precipitation occurs from late fall to late winter in the  Pacific Northwest and west of the Continental Divide in the Rocky  Mountains north of Utah and Wyoming. East of the Divide, in the Rocky  Mountains north of New Mexico and Arizona, the heaviest precipitation  comes in late winter and early spring. In the Rocky Mountains and  associated ranges in Arizona and New Mexico, most precipitation comes  during late summer and early fall (5,10,58). However, 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.

    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.

Coastal, subalpine coniferous forests; 1100--2300m.

Systems

• Terrestrial

Comments: Forested flats and slopes to subalpine slopes near timberline.

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).

In the Rocky Mountains, subalpine fir is most typically found in mixture  with Engelmann spruce (Picea engelmannii) and forms the relatively  stable Engelmann Spruce-Subalpine Fir (Type 206) forest cover type. It is  also found in varying degrees in 16 other cover types (56):

      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).

Subalpine fir is susceptible to windthrow.  Although, this tendency is generally attributed to a shallow root system,  soil depth, drainage, and stand conditions influence the development of  the root system. The kind and intensity of cutting and topographic  exposure to wind also influence the likelihood of trees being windthrown  (5).

    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.

High intensity crown fires which are common in subalpine fir forests,
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.

More info for the terms: duff, fuel, snag

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
burned. 

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

Subalpine fir is very fire sensitive and is often killed even by surface
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 [93]. 

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
[130] but readily germinate on mineral soil seedbeds prepared by
broadcast burning [16,107].

More info for the term: prescribed 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.

More info for the term: tree

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 [107].  Ash does not affect germination, but if it is deep, it
can prevent a seedling's roots from reaching mineral soil [85].
Although seedling establishment is often favored by shade, it will
establish in full sunlight following fire [87].

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 [16].  In Colorado, Peet [90] 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)
away.

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 [128].

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 [34].  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
[90].  It may take 50 to 150 years after a fire for substantial
subalpine fir establishment under dense lodgepole pine stands
[18,109,128].

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 [4].  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 [4].

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
[18].  Grasses and sedges may form a mat in subalpine meadows which
prevents tree seeds from reaching mineral soil [109].

More info for the term: lichen

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 [34].

More info for the term: secondary colonizer

   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

More info for the terms: crown fire, frequency, fuel, lichens, tree

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
[14].  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
                                                       (years)
Kananaskis Park, AB      subalpine fir, spruce,          90       [12]
                         lodgepole pine        
northern Cascades, WA    subalpine fir                 154        [2]
northern Cascades, WA    subalpine fir-lodgepole pine  109        [2]
Olympic NP, WA           subalpine fir                 150        [116]
Yellowstone NP, WY       subalpine fir                 300-350    [98]
Coram Exp. Forest, nw MT western larch, Douglas-fir,   117-146    [129]
                         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 [1].  Fuel beds
tend to be irregular, with over twice as much fuel accumulating under
the narrow-crowned trees as between them [116].  The needles are small
and fine and form a compact fuel bed in which fire spreads slowly [34].
These concentrated, slow burning fuels frequently produce flames high
enough to reach subalpine fir's low-growing dead branches [116].  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 [62].

More info on this topic.

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 [11].  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
[11].

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 [43].  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 [43].

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 [29].  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].

More info for the terms: climax, duff, layering, litter, natural, tree

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 [11].  Corkbark fir generally does not produce cones
until about 50 years old [39].  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 [39].  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 [9].  Subalpine fir averages 34,800 seeds per pound
(76,700/kg), while corkbark fir seeds average 22,300 per pound
(49,150/kg) [41].

Seed predation:  Insect pests reduce seed yields by feeding on cones and
seeds; however, the magnitude of loss is variable [11].  Red squirrels
cut and cache large quantities of subalpine fir cones [9].  After
dispersal, numerous small rodents and birds consume seeds from the
ground.

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
[9].  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 [86].  Some seeds are also dispersed by red squirrels
which cut and cache cones before they disintegrate; seeds commonly
germinate from these middens, forming thickets [71].

Germination and viability:  Seeds overwinter under or in snow.  This
cold, moist stratification is required for germination [41].
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 [41].  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 [11].  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 [35].  At lower elevations,
seedling densities are often greater on mineral soils [35].  In a
spruce-fir forest in southeastern Wyoming, Knapp and Smith [67] 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)
[67].

Growth:  Subalpine fir seedlings grow very slowly.  One-year-old
seedlings are frequently less than 1 inch (2.5 cm) tall [11].  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 [11].  Under favorable conditions
trees reach a height of 4 to 5 feet (1.2-1.5 m) in 20 to 40 years [11].
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 [13].
Under closed forest canopy, reproduction by layering is negligible.

More info on this topic.

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

More info for the term: tree

Tree

fall/severe

In the Rocky Mountains and Pacific  Northwest where subalpine fir and Engelmann spruce form the spruce-fir  type, and mountain hemlock and other true firs are absent or limited in  number, subalpine fir is very shade-tolerant (22). It is much more  tolerant than spruce and other common associates such as lodgepole pine,  aspen, blue spruce, and interior Douglas-fir (11). However, in most of the  Cascades and in the Rocky Mountains, where subalpine fir grows with the  more shade-tolerant Pacific silver fir, grand fir, and mountain hemlock,  some ecologists classify it as intolerant relative to these associates  (22).

    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).

Subalpine fir has a shallow root system on sites  that limit the depth of root penetration, and where the superficial  lateral root system common to the seedling stage persists to old age.  Under more favorable conditions, subalpine fir develops a relatively deep  lateral root system (9).

More info on this topic.

More info for the term: phenology

Subalpine fir requires 2 years to complete its reproductive cycle [115].
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 [115].  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               [41]

male bud burst      Linn, OR         early to mid-May       
female bud burst        "            mid to late May        
pollen shed             "                 June              
seed dispersal begins   "              early October          [45]

flowering        AZ, San Fran.Peaks     late June           
cone ripening           "           mid-Sept - early Oct    
seed dispersal          "           late Sept - early Oct     [41]

Subalpine fir frequently reproduces by  layering where the species is a pioneer in developing forest cover on  severe sites such as lava flows and talus slopes or near timberline (22).  Under closed-forest conditions, reproduction by layering is of minor  importance.

Under natural conditions, fir seeds lie  dormant under the snow and germinate the following spring. Although  germination and early survival of subalpine fir are generally best on  exposed mineral soil and moist humus, the species is less exacting in its  seedbed requirements than most of its common associates. Subalpine fir has  been observed to germinate and survive on a wide variety of other seedbed  types including the undisturbed forest floor, undecomposed duff and  litter, and decaying wood (9,15,19). Subalpine fir also invades and  establishes on severe sites such as recent bums, lava flows, talus slopes,  avalanche tracks, and climatically severe regions near timberline (22).  Subalpine fir succeeds on these open sites 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.

    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).

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  (9,60).

    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).

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 (45,60).

On exposed sites near timberline, subalpine  fir is often reduced to a prostrate shrub, but under closed-forest  conditions it attains diameters of 30 to 61 cm (12 to 24 in) and heights  of 14 to 30 m (45 to 100 ft), depending upon site quality and stand  density. Trees larger than 76 cm (30 in) in diameter and 39.6 m (130 ft)  in height are exceptional (57).

    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).

Population Differences    Information on subalpine fir population differences is virtually  nonexistent. Undoubtedly, any species with the range in elevation and  latitude of subalpine fir will exhibit differences in growth, phenology,  dormancy, resistance to heat and cold, etc, among different populations.

    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.

The following is a representative barcode sequence, the centroid of all available sequences for this species.


No available public DNA sequences.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 3
Specimens with Barcodes: 3
Species With Barcodes: 1

Canada

Rounded National Status Rank: N5 - Secure

United States

Rounded National Status Rank: N5 - Secure

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.

More info for the terms: seed tree, selection, tree, tussock

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 [11].  The seed tree method is
generally not used because of the susceptibility of subalpine fir to
windthrow [11].  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 [8].  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 [11].  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 [21].  The balsam woolly aphid has
virtually eliminated subalpine fir from some stands in the Cascades
[11].  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 [102].
Subalpine fir is most seriously affected by this disease in the northern
and central Rocky Mountains [123], and is affected to a lesser extent in
the Pacific Northwest [102].  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
[39].  Trees weakened by wood rots often become infested by fir engraver
beetles and usually succumb to windfall and breakage [11].  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 [11].

Habitat for threatened and endangered species:  Old-growth subalpine fir
stands in northern Idaho may provide critical habitat for woodland
caribou [23].  Numerous subalpine fir habitat types, especially those
containing huckleberries (Vaccinium spp.), provide critical habitat for
grizzly bears [127].

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.

More info for the term: tree

Subalpine fir can be planted on disturbed sites within forest vegetation
types where it naturally occurs [92].  It is generally recommended for
cool and moist sites within subalpine areas [120].  Its erosion control
potential is listed as medium in Utah and Montana, and high in Colorado
[30].  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 [92].  Seedlings exhibit very slow
initial growth and are therefore usually outplanted as 2- to 3-year-old
seedlings [41].  Wild seedlings may also be transplanted [120].  A
maximum spacing of 10 x 10 feet (3 x 3 m) has been recommended for
seedlings or transplants [120].  Methods for collecting, processing,
testing, storing, and planting subalpine fir seeds have been discussed
in detail [32,41].

More info for the term: cover

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 [113].  Dense stands provide cool summertime shade for big
game animals [71].  In Yellowstone National Park, grizzly bear daybeds
are often found in subalpine fir stands [19].

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
[103].  Subalpine fir snags are used by numerous cavity-nesting birds,
but are generally less preferred than those of associated conifers
[105].

The degree to which subalpine fir provides environmental protection
during one or more seasons for wildlife species is as follows [30]:

                       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

Subalpine fir is low in protein value but fair in energy value [30].
Percent composition of subalpine fir browse collected near Jackson Hole,
Wyoming, was as follows [61]:

  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 [110]:

      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

The palatability of subalpine fir to domestic livestock is low [30].
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 [77].  Red squirrels generally eat subalpine fir seeds
after other cached conifer seeds have been consumed [71].  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
[30,61,89,96]:

                       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  ----

More info for the term: cover

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
[99].  Throughout much of Montana, Idaho, and Wyoming, subalpine fir is
an important winter food of moose [89].  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 [61].  In Yellowstone National Park, grizzly
bears sometimes strip the bark of subalpine fir to feed on the
underlying cambium [19].  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
[103,113].

Subalpine fir seeds are eaten by several species of small mammals and
birds.  Red squirrels eat seeds from cached subalpine fir cones [71].
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
[49].  Small birds may make considerable use of fir seeds, but their
foraging is scattered and sporadic throughout subalpine forests [49].

Subalpine fir wood is odorless, light-weight, soft, and low in bending
and compressive strength [11].  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 [9].  Subalpine fir has excellent pulping properties [9].  Use
for poles and pilings requires large amounts of preservatives because
the wood decays rapidly [108].

Subalpine fir is sometimes used as a landscape plant to produce
screenings or windbreaks [114].  In the Pacific Northwest it is
sometimes transplanted into rock gardens or simulated subalpine settings
[69].

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 [53].

Resin from the bark is used in the optical industry and in laboratories
as a cement for lenses and microscope slides [71].

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  (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.

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. 

 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).

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.