Index of Species Information
SPECIES: Tsuga mertensiana
SPECIES: Tsuga mertensiana
|Mountain hemlock grove in Emigrant Wilderness
Area, CA. Photo by Janet L. Fryer, USFS, Fire Sciences
AUTHORSHIP AND CITATION :
Tesky, Julie L. 1992. Tsuga mertensiana. In: Fire Effects Information System, [Online].
U.S. Department of Agriculture, Forest Service, Rocky Mountain Research Station,
Fire Sciences Laboratory (Producer). Available:
SCS PLANT CODE :
COMMON NAMES :
The currently accepted scientific name for mountain hemlock is Tsuga
mertensiana (Bong.) Carriere [38,46,49]. Mountain hemlock in the
Siskiyous from the Oregon-California border south were recently
classified as Tsuga mertensiana spp. grandicona Farjon, in recognition
of the generally larger cones of trees in this region . All others
are classified as Tsuga mertensiana spp. mertensiana. There are no
recognized varieties or forms. Mountain hemlock will hybridize with
western hemlock (T. heterophylla) .
LIFE FORM :
FEDERAL LEGAL STATUS :
No special status
OTHER STATUS :
DISTRIBUTION AND OCCURRENCE
SPECIES: Tsuga mertensiana
GENERAL DISTRIBUTION :
Mountain hemlock occurs along the crest of the Sierra Nevada; the Coast
Ranges and Cascade Range in Oregon; the Cascade Range and Olympic
Mountains in Washington; the northern Rocky Mountains in Idaho and
western Montana; the Insular, Coast, and Columbia mountains in British
Columbia; and in southeast and south-central Alaska [4,8,32,46]. In
California it is also locally abundant in the Klamath Mountains. The
extreme southern limit of mountain hemlock is near Silliman Lake in
Tulare County, California .
FRES11 Spruce - fir
FRES22 Western white pine
FRES23 Fir - spruce
FRES24 Hemlock - Sitka spruce
FRES26 Lodgepole pine
AK CA ID MT OR WA AB BC
BLM PHYSIOGRAPHIC REGIONS :
1 Northern Pacific Border
2 Cascade Mountains
4 Sierra Mountains
8 Northern Rocky Mountains
KUCHLER PLANT ASSOCIATIONS :
K001 Spruce - cedar - hemlock forest
K002 Cedar - hemlock - Douglas-fir forest
K003 Silver fir - Douglas-fir forest
K004 Fir - hemlock forest
K008 Lodgepole pine - subalpine forest
K013 Cedar - hemlock - pine forest
SAF COVER TYPES :
205 Mountain hemlock
206 Engelmann spruce - subalpine fir
207 Red fir
208 Whitebark pine
210 Interior Douglas-fir
212 Western larch
215 Western white pine
218 Lodgepole pine
256 California mixed subalpine
SRM (RANGELAND) COVER TYPES :
HABITAT TYPES AND PLANT COMMUNITIES :
Mountain hemlock commonly occurs as a dominant or codominant in
high-elevation alpine or subalpine forests. In western Washington and
Oregon, the mountain hemlock zone is the highest forested zone .
Mountain hemlock is often codominant with Pacific silver fir (Abies
amabilis) [1,21]. One of the most widespread mountain hemlock
communities is the mountain hemlock-Pacific silver fir/big huckleberry
(Vaccinium membranaceum) type found in British Columbia and the Oregon
and Washington Cascades. In the Rocky Mountains, the mountain
hemlock/beargrass (Xerophyllum tenax) habitat type is generally found on
south slopes and is characterized by a high cover of beargrass with big
huckleberry and grouse whortleberry (V. scoparium) as common associates.
A similar Pacific silver fir-mountain hemlock/beargrass association is
found in Oregon . Published classifications identifying mountain
hemlock as a dominant or codominant are as follows:
Forest types of the North Cascades National Park Service complex .
Preliminary plant associations of the Southern Oregon Cascade Mountain
Preliminary plant associations of the Siskiyou Mountain Province .
Plant association and management guide for the Pacific silver fir zone .
Forest habitat types of northern Idaho: A second approximation .
Classification of montane forest community types in the Cedar River
drainage of western Washington, U.S.A. .
Preliminary forest plant association management guide. Ketchikan area,
Tongass National Forest .
Subalpine plant communities of the western North Cascades, Washington .
Alpine and high subalpine plant communities of the North Cascades Range,
Washington and British Columbia .
Fire ecology of western Montana forest habitat types .
Forest vegetation of the montane and subalpine zones, Olympic Mountains,
Natural vegetation of Oregon and Washington .
The forest communities of Mount Rainier National Park .
Plant associations of south Chiloquin and Klamath ranger districts--
Winema National forest .
Vegetation and environment in old growth forests of northern southeast
Alaska: a plant association classification .
Forest habitat types of Montana .
Preliminary classification of forest vegetation of the Kenai Peninsula,
Preliminary forest plant associations of the Stikine area, Tongass
National Forest .
SPECIES: Tsuga mertensiana
WOOD PRODUCTS VALUE :
Mountain hemlock is largely inaccessible because of the high altitudes
at which it occurs and is unimportant as commercial timber . It is,
however, harvested to a limited extent near its lower limits; the wood
is generally marketed with western hemlock [71,4]. The wood is
moderately strong and light colored and is most often used for
small-dimension lumber and pulp . The wood is also used for railway
ties, mine timbers, interior finish, crates, kitchen cabinets, and
flooring and ceilings . Nearly pure stands of mountain hemlock on
Prince of Wales Island have been logged for pulp .
IMPORTANCE TO LIVESTOCK AND WILDLIFE :
Mountain hemlock stands provide good hiding and thermal cover for many
wildlife species [8,45]. Sites dominated by mountain hemlock provide
important summer range for deer in Alaska and Vancouver Island because
of abundant nutrient-rich forbs available in the understory [19,49]. In
Montana, mountain hemlock habitat types provide summer range for mule
deer, elk, and bear . Mountain hemlock seeds have been found in the
stomachs of crows and grouse .
NUTRITIONAL VALUE :
COVER VALUE :
VALUE FOR REHABILITATION OF DISTURBED SITES :
Mountain hemlock is important for watershed protection . The
mountain hemlock/blueberry (Vaccinium spp.)-copperbush (Cladothamnus
pyrolaeflorus)/deer cabbage (Fauria crista-galli) association in Alaska
captures runoff from snowmelt . Planted stock of mountain hemlock
does not perform well. In high-elevation regeneration trials in the
Vancouver forest region, its performance was poor compared to that of
the other high-elevation species. Natural regeneration may perform
OTHER USES AND VALUES :
Mountain hemlock is often used as an ornamental for landscaping in the
Pacific Northwest and throughout Great Britain [42,49,4]. Its dense,
compact foliage coupled with its slow growth make it ideal as a garden
evergreen . Hemlock species (Tsuga spp.) played a supernatural role
as magical objects in the mythology of the Thompson and Lillooet
Interior Salish of British Columbia .
OTHER MANAGEMENT CONSIDERATIONS :
Insects and disease: Mountain hemlock is very susceptible to laminated
root rot (Phellinus weiri) [20,49]. In the high Cascades of central
Oregon mountain hemlock is the most susceptible tree. This fungus
spreads from centers of infection along tree roots so that all trees are
killed in circular areas that expand radially. Laminated root rot moves
faster through a nearly pure stand of mountain hemlock than through a
more heterogeneous conifer stand. Growth and coalescence of laminated
rot root pockets in mountain hemlock have produced infected areas of
more than 100 acres (40 ha). Seedlings are not susceptible to
reinfection by laminated root rot for 80 to 120 years. This may be due
to greater vigor caused by higher levels of available nitrogen, higher
temperatures, and more growing-season moisture in this regrowth zone
Other common fungal and parasite pests of mountain hemlock include
several heart rots, of which Indian paint fungus (Echinodontium
tinctorum) is the most common and damaging; several needle diseases;
snow mold (Herpotrichia nigra); and dwarf-mistletoe (Arceuthobium
Mountain hemlock is an occasional host for the western spruce budworm
(Choristoneura occidentalis) .
Frost tolerance: Mountain hemlock is very frost tolerant .
Wind damage: Because mountain hemlock is shallow rooted it is very
susceptible to windthrow. In the coastal strip of British Columbia and
Alaska, wind commonly destroys mountain hemlock by uprooting it. As
cutting is increased in mountain hemlock forests, windthrow will
probably become a more common cause of mortality .
Silvicultural considerations: Many sites dominated by mountain hemlock
are particularly difficult to reforest following clearcutting. In the
Gifford Pinchot, Mount Hood, and Willamette national forests, field
observations showed that the mountain hemlock/big huckleberry/beargrass
and mountain hemlock/grouse whortleberry associations are particularly
difficult to reforest due to a short growing season in a harsh
environment. Artificial reforestation within 5 years following
clearcutting and burning on these sites may not be possible .
The deep, persistent snowpack; short, cool growing season; and poorly
developed soils make regeneration difficult and productivity low for the
mountain hemlock series of the Siskiyou region of southwestern Oregon.
When mountain hemlock stands are managed for timber production, the
following silvicultural considerations are important :
(1) Advanced regeneration and subsequent natural regeneration may
provide the most reliable source for a new stand in 5 years. Protection
from damage during harvest is essential. Damaged regeneration is very
susceptible to rot.
(2) Natural regeneration after harvest establishes sooner in small
openings than large openings and is often most rapid on the shaded south
edges of clearcuts. Keeping clearcuts small to maximize these edge
effects will probably speed regeneration, but it may still be
unsatisfactory in 5 years. The shelterwood system can provide adequate
regeneration in 5 to 10 years.
(3) Planting has been ineffective on these cold, snowy sites. Timing is
critical for artificial regeneration. Plant soon after snow melts.
In British Columbia, the recommended silvicultural method for harvest of
old-growth mountain hemlock is clearcut followed by natural
regeneration. For young natural stands that have developed after fire
or second-growth stands that have developed after clearcutting, the
clearcut method with natural regeneration, seed tree method, or
shelterwood method is recommended .
BOTANICAL AND ECOLOGICAL CHARACTERISTICS
SPECIES: Tsuga mertensiana
GENERAL BOTANICAL CHARACTERISTICS :
Mountain hemlock is a native, slow-growing, coniferous, evergreen tree
usually 75 to 100 feet (23-30 m) tall and 2.5 to 3.5 feet (0.8-1 m) in
diameter . However, it takes on a variety of growth forms to adapt
to subalpine conditions. Below 4,000 feet (1219 m) in the Coast Ranges,
it grows in dense stands reaching diameters of 3 to 4 feet (0.8-0.9 m)
and heights up to 150 feet (46 m) . On exposed ridges at high
elevations, it often grows as a low-spreading shrub or small tree
In the open, mountain hemlock develops a strongly tapered trunk bearing
slender branches almost to the ground; the branches usually droop and
often have ascending tips. The outline of the crown is narrowly conical
beneath a slender drooping leader. Crowns of old trees are often bent
or twisted. In dense stands, the crown covers only the upper half or
less of the tree, and the trunk below develops with a more gradual
taper, and becomes virtually clear of branches . The twigs are
mostly short and slender. The needles are crowded on all sides of short
twigs and curved upward .
The bark is thick and deeply furrowed into scaly plates on old trees
[44,72]. The bark is early broken and rough on young trees . The
root system is shallow and widespreading [38,49,59].
RAUNKIAER LIFE FORM :
REGENERATION PROCESSES :
Seed production and dissemination: Mountain hemlock begins producing
seed at about age 20. Mature trees 175 to 250 years old produce
moderate to very heavy cone crops at about 3-year intervals in Oregon
and Washington, but crops may be complete failures in other years .
Cones average about 70 to 100 seeds . There are 102,000 to 207,000
seeds per pound . On one study site located at Santiam Pass,
Oregon, the largest number of cones counted was 1,700 on a 20-inch (51
cm) mountain hemlock . Over 1,000 cones per tree were counted on
many other trees during the 5 year study period. Seed production is
better during normal to wet growing seasons than during dry growing
Mountain hemlock's winged seeds are dispersed primarily by wind.
Germination is epigeal and occurs on snow, or mineral or organic soil if
sufficient moisture is available . Germination rates range from 47
to 75 percent [28,49]. Cold stratification of mature seeds shortens
incubation time and may substantially increase germination . Heavy
seeds germinate more rapidly than seeds with low percent dry weight.
Along the eastern high Cascades in Oregon, seed viability of mountain
hemlock varied from 36 to 76 percent over a 2-year period .
Seedling development: Young seedlings grow best in partial shade and
early development is often slow. Seedlings are relatively drought
intolerant . Increasing light intensity and day length increase
seedling height but delay or prevent terminal bud formation under
shelter. Healthy mountain hemlock saplings respond well to release, in
both diameter and height growth. Seedlings and small saplings of
mountain hemlock tolerate heavy snowpacks well .
Vegetative reproduction: Mountain hemlock reproduces vegetatively by
layering [49,73]. This is an effective means of regenerating at
timberline, since layered saplings are sheltered by the growth of the
parent tree and initially receive their nutrients through the
established root system of the old tree . Layering is an important
method of reproduction on muskegs and krummholz areas in Alaska .
SITE CHARACTERISTICS :
Mountain hemlock is commonly found on cold, snowy subalpine or boreal
sites where it grows slowly, sometimes reaching more than 800 years of
age. Though pure stands are less common than mixed stands, extensive
pure stands of mountain hemlock do occur in Alaska and in the central
high Cascades of Oregon . In the Siskiyous, mountain hemlock is
generally confined to cool, north-facing, cirquelike topography. It
does not form extensive stands like those in the Cascades because
suitable habitat is found only on the highest peaks. In the Siskiyous,
the lower limit of mountain hemlock is governed by high temperatures and
competition with Shasta red fir (Abies magnifica shastensis) .
Mountain hemlock in western Montana is generally confined to the moist,
upper slopes of the Bitterroot Mountains .
Elevational range: The elevational range of mountain hemlock has been
recorded as follows [8,49]:
Alaska - 0 to 3,500 feet (0-1,067 m)
southern British Columbia - 1,000 to 3,000 feet (300-900 m)
northern Washington - 4,200 to 5,600 feet (1,300-1,700 m)
Rocky Mountains - 5,100 to 6,900 (1,550-2,100 m)
southern Oregon - 5,200 to 7,500 (1,600- 2,300 m)
Siskiyous - 4,000 to 7,000 (1,220 - 2,134 m)
northern Sierra Nevada - 7,900 to 10,000 (2,400-3,050 m)
southern Sierra Nevada - 9,050 to 10,000 (2,750-3,500 m)
Climate: Mountain hemlock generally occurs on sites with mild to cold
winters; short, warm to cool growing seasons; and moderate to high
precipitation . Average annual snowfall ranges from about 32 to 50
feet (10-15 m) .
Soils: Mountain hemlock grows on soils derived from a wide variety of
parent materials, however, it is rare and stunted on soils derived from
calcareous parent materials in the Selkirk Mountains of British
Columbia. It is found on organic soils in the northern portion of its
range more often than in the southern portion. In Alaska it is found on
organic soils bordering muskegs where it may be a major stand component.
Best development of mountain hemlock is on loose, coarse-textured,
well-drained soils with adequate moisture . In British Columbia
best growth is on thick, very acidic organic matter and decayed wood.
In the Siskiyous, soils in the mountain hemlock series are loam to silt
loam and average 40 inches (100 cm) in depth . Adequate soil
moisture appears to be especially important in California and Montana.
Soils are typically acidic with a pH ranging from 3.4 to 5.0 . In
the Coastal Mountains, mountain hemlock can grow on the rockiest soils,
even including recent lava flows, if moisture is adequate . The
nutritional requirements of mountain hemlock are low .
Plant associates: In mixed stands, mountain hemlock usually coexists
with subalpine fir (Abies lasiocarpa), Pacific silver fir, or
Alaska-cedar (Chamaecyparis nootkatensis). In Montana, subalpine fir
and Engelmann spruce (Picea engelmannii) are nearly constant associates
of mountain hemlock . Common understory associates with mountain
hemlock are as follows: beargrass, big huckleberry, grouse
whortleberry, rustyleaf menziesia (Menziesia ferruginea), Cascades
azalea (Rhododendron albiflorum), Alaska huckleberry (V. alaskaense),
ovalleaf huckleberry (V. ovalifolium), long-stoloned sedge (Carex inops
ssp. inops), mertens cassiope (Cassiope mertensiana), copperbush,
mountain heather, deer cabbage, marsh marigold (Caltha biflora), and
skunk cabbage (Lysichitum americanium) [1,19,33,68].
SUCCESSIONAL STATUS :
Mountain hemlock is shade tolerant [24,49,4]. It is considered a major
or minor climax species over most of its habitat; however, it is also a
pioneer on glacial moraines in British Columbia and Alaska. Mountain
hemlock is commonly the major climax species in the mountain hemlock
zone south of central Oregon where Pacific silver fir does not occur.
It often succeeds lodgepole pine (Pinus contorta) when these species
pioneer on drier sites and tends to replace Engelmann spruce .
Mountain hemlock is considered a coclimax species with subalpine fir
where they occur together [17,25]. In the subalpine fir series in the
Lolo National Forest, mountain hemlock and subalpine fir are the only
two trees capable of perpetuating themselves as climax dominants .
SEASONAL DEVELOPMENT :
Mountain hemlock has a 2-year reproductive cycle. Pollination occurs in
the spring or early summer of the second year . Mountain hemlock
releases pollen in June in the Cascade Range in Oregon, from mid-June to
mid-July in British Columbia, and from mid-May to late June in Alaska
. Fertilization occurs from about late July to early August in
British Columbia. Reproductive buds can easily be identified in the
late summer and fall. Cones ripen and open from late September to
November [49,56]. In the Bitterroot Mountains of Idaho cones ripen in
August . In Montana cones open and release the wide-winged seeds in
September or October and then abscise .
SPECIES: Tsuga mertensiana
FIRE ECOLOGY OR ADAPTATIONS :
Mountain hemlock is not well adapted to fire . Fire resistance of
mountain hemlock has been rated as low . Its relatively thick bark
provides some protection, but low-hanging branches, highly flammable
foliage, and a tendency to grow in dense groups make it very susceptible
to fire injury .
Mountain hemlock sites are typically moist with average precipitation
over 50 inches (127 cm), making fire occurrence low (400-800 years)
[7,11,34]. Fuel loading in these sites is often low . In the
Pacific Northwest, the estimated prelogging fire regime in mountain
hemlock forest types is 611 years . Fires in these cool wet forest
types generally occur as infrequent crown fires. When fires do occur in
mountain hemlock forests, they are often severe stand-replacing fires
FIRE REGIMES :
Find fire regime information for the plant communities in which this
species may occur by entering the species name in the FEIS home page under
"Find Fire Regimes".
POSTFIRE REGENERATION STRATEGY :
Tree without adventitious-bud root crown
Secondary colonizer - off-site seed
SPECIES: Tsuga mertensiana
IMMEDIATE FIRE EFFECT ON PLANT :
Mountain hemlock is easily killed by fire [7,73,65]. The most common
method of killing is root charring and crown scorching . In a
krummholz community of the North Cascades, Washington, all but one
mountain hemlock were killed by fire .
DISCUSSION AND QUALIFICATION OF FIRE EFFECT :
PLANT RESPONSE TO FIRE :
Mountain hemlock is generally slow to regenerate after fire [25,49].
Most burned areas in the mountain hemlock zone on the Olympic Peninsula
do not have adequate stocking for commercial forests even 55 to 88 years
after wildfire . Tree establishment in burned areas is higher
during normal to wet growing seasons .
DISCUSSION AND QUALIFICATION OF PLANT RESPONSE :
FIRE MANAGEMENT CONSIDERATIONS :
Fire injury makes mountain hemlock very susceptible to insects and
disease [17,25]. Old-growth mountain hemlock stands 460 years or older
are very susceptible to stand-replacing fires .
In northern Idaho, burning slash produced better stocking of mountain
hemlock natural regeneration compared to leaving slash untreated.
However, manual scarification generally produced better stocking than
did burning. In contrast, slash burning in Oregon increased the time it
took mountain hemlock to reach 60 percent stocking .
References for species: Tsuga mertensiana
1. Agee, James K.; Kertis, Jane. 1987. Forest types of the North Cascades National Park Service Complex. Canadian Journal of Botany. 65: 1520-1530. 
2. Agee, James K.; Smith, Larry. 1984. Subalpine tree reestablishment after fire in the Olympic Mountains, Washington. Ecology. 65(3): 810-819. 
3. Antos, Joseph A.; Zobel, Donald B. 1984. Ecological implications of belowground morphology of nine coniferous forest herbs. Botanical Gazette. 145(4): 508-517. 
4. Arno, Stephen F.; Hammerly, Ramona P. 1977. Northwest trees. Seattle, WA: The Mountaineers. 222 p. 
5. Atzet, Thomas; McCrimmon, Lisa A. 1990. Preliminary plant associations of the southern Oregon Cascade Mountain Province. Grants Pass, OR: U.S. Department of Agriculture, Forest Service, Siskiyou National Forest. 330 p. 
6. Atzet, Thomas; Wheeler, David L. 1984. Preliminary plant associations of the Siskiyou Mountain Province. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 278 p. 
7. Atzet, Thomas; Wheeler, David L. 1982. Historical and ecological perspectives on fire activity in the Klamath Geological Province of the Rogue River and Siskiyou National Forests. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 16 p. 
8. Atzet, Tom; Wheeler, David; Riegel, Gregg; [and others]. 1984. The mountain hemlock and Shasta red fir series of the Siskiyou Region of southwest Oregon. FIR Report. 6(1): 4-7. 
9. Barrett, Stephen W. 1982. Fire's influence on ecosystems of the Clearwater National Forest: Cook Mountain fire history inventory. Orofino, ID: U.S. Department of Agriculture, Forest Service, Clearwater National Forest. 42 p. 
10. Bernard, Stephen R.; Brown, Kenneth F. 1977. Distribution of mammals, reptiles, and amphibians by BLM physiographic regions and A.W. Kuchler's associations for the eleven western states. Tech. Note 301. Denver, CO: U.S. Department of the Interior, Bureau of Land Management. 169 p. 
11. Booth, Douglas E. 1991. Estimating prelogging old-growth in the Pacific Northwest. Journal of Forestry. 89(10): 25-29. 
12. Brockway, Dale G.; Topik, Christopher; Hemstrom, Miles A.; Emmingham, William H. 1985. Plant association and management guide for the Pacific silver fir zone: Gifford Pinchot National Forest. R6-Ecol-130a. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 122 p. 
13. Brown, Ray W.; Johnston, Robert S.; Johnson, Douglas A. 1978. Rehabilitation of alpine tundra disturbances. Journal of Soil and Water Conservation. 33: 154-160. 
14. Carlson, Clinton E.; Fellin, David G.; Schmidt, Wyman C. 1983. The western spruce budworm in northern Rocky Mountain forests: a review of ecology, past insecticidal treatments and silvicultural practices. In: O'Loughlin, Jennifer; Pfister, Robert D., eds. Management of second-growth forests: The state of knowledge and research needs: Proceedings of a symposium; 1982 May 14; Missoula, MT. Missoula, MT: University of Montana, School of Forestry, Montana Forest and Conservation Experiment Station: 76-103. 
15. Cooper, Stephen V.; Neiman, Kenneth E.; Roberts, David W. 1991. (Rev.) Forest habitat types of northern Idaho: a second approximation. Gen. Tech. Rep. INT-236. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 143 p. 
16. Dale, Virginia H.; Hemstrom, Miles A.; Franklin, Jerry F. 1984. The effect of disturbance frequency on forest succession in the Pacific Northwest. In: New forests for a changing world: Proceedings of the 1983 convention of The Society of American Foresters; 1983 October 16-20; Portland, OR. Bethesda, MD: Society of American Foresters: 300-304. 
17. Davis, Kathleen M.; Clayton, Bruce D.; Fischer, William C. 1980. Fire ecology of Lolo National Forest habitat types. INT-79. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 77 p. 
18. del Moral, Roger; Long, James N. 1977. Classification of montane forest community types in the Cedar River drainage of western Washington, U.S.A. Canadian Journal of Forest Research. 7: 217-225. 
19. DeMeo, Thomas. 1989. Preliminary forest plant association management guide: Ketchikan Area, Tongass National Forest. [Portland, OR]: [U.S. Department of Agriculture, Forest Service]. 164 p. 
20. Dickman, Alan; Cook, Stanton. 1989. Fire and fungus in a mountain hemlock forest. Canadian Journal of Botany. 67(7): 2005-2016. 
21. Douglas, George W. 1972. Subalpine plant communities of the western North Cascades, Washington. Arctic and Alpine Research. 4(2): 147-166. 
22. Douglas, George W.; Bliss, L. C. 1977. Alpine and high subalpine plant communities of the North Cascades Range, Washington and British Columbia. Ecological Monographs. 47: 113-150. 
23. Eyre, F. H., ed. 1980. Forest cover types of the United States and Canada. Washington, DC: Society of American Foresters. 148 p. 
24. Feller, M. C. 1982. The ecological effects of slashburning with particular reference to British Columbia: a literature review. Victoria, BC: Ministry of Forests. 60 p. 
25. Fischer, William C.; Bradley, Anne F. 1987. Fire ecology of western Montana forest habitat types. Gen. Tech. Rep. INT-223. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 95 p. 
26. Fiske, John N.; DeBell, Dean S. 1989. Silviculture of Pacific coast forests. In: Burns, Russell M., compiler. The scientific basis for silvicultural and management decisions in the National Forest System. Gen. Tech. Rep. WO-55. Washington, DC: U.S. Department of Agriculture, Forest Service: 59-78. 
27. Fonda, R. W.; Bliss, L. C. 1969. Forest vegetation of the montane and subalpine zones, Olympic Mountains, Washington. Ecological Monographs. 39(3): 271-301. 
28. Franklin, J. F. 1968. Cone production by upper slope conifers. Research Paper PNW-60. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 21 . 
29. Franklin, Jerry F.; Dyrness, C. T. 1973. Natural vegetation of Oregon and Washington. Gen. Tech. Rep. PNW-8. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 417 p. 
30. Franklin, Jerry F.; Moir, William H.; Hemstrom, Miles A.; [and others]. 1988. The forest communities of Mount Rainier National Park. Scientific Monograph Series No 19. Washington, DC: U.S. Department of the Interior, National Park Service. 194 p. 
31. Garrison, George A.; Bjugstad, Ardell J.; Duncan, Don A.; [and others]. 1977. Vegetation and environmental features of forest and range ecosystems. Agric. Handb. 475. Washington, DC: U.S. Department of Agriculture, Forest Service. 68 p. 
32. Griffin, James R.; Critchfield, William B. 1972. The distribution of forest trees in California. Res. Pap. PSW-82. Berkeley, CA: U.S. Department of Agriculture, Forest Service, Pacific Southwest Forest and Range Experiment Station. 118 p. 
33. Habeck, James R. 1967. Mountain hemlock communities in western Montana. Northwest Science. 41(4): 169-177. 
34. Habeck, James R. 1985. Impact of fire suppression on forest succession and fuel accumulations in long-fire-interval wilderness habitat types. In: Lotan, James E.; Kilgore, Bruce M.; Fisher, William C.; Mutch, Robert W., technical coordinators. Proceedings-Symposium and Workshop on Wilderness Fire; 1983 November 15 - November 18; Missoula, MT. General Technical Report INT-182. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station: 110-118. 
35. Halverson, Nancy M.; Emmingham, William H. 1982. Reforestation in the Cascades Pacific silver fir zone: A survey of sites and management experiences on the Gifford Pinchot, Mt. Hood and Willamette National Forests. U.S. Department of Agriculture Forest Service R-6 Area Guide R6-ECOL-091-1982. Pacific Northwest Region, Portland, Oregon 37 p. 
36. Hjeljord, Olav. 1973. Mountain goat forage and habitat preference in Alaska. Journal of Wildlife Management. 37(3): 353-362. 
37. Hopkins, William E. 1979. Plant associations of south Chiloquin and Klamath Ranger Districts--Winema National Forest. R6-Ecol-79-005. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Region. 96 p. 
38. Hosie, R. C. 1969. Native trees of Canada. 7th ed. Ottawa, ON: Canadian Forestry Service, Department of Fisheries and Forestry. 380 p. 
39. Huff, Mark. 1988. Mount Rainier: fire and ice. Park Science. 8(3): 22-23. 
40. Klinka, K.; Feller, M. C.; Green, R. N.; [and others]. 1990. Ecological principles: applications. In: Lavender, D. P.; Parish, R.; Johnson, C. M.; [and others], eds. Regenerating British Columbia's forests. Vancouver, BC: University of British Columbia Press: 55-72. 
41. Krajina, V. J.; Klinka, K.; Worrall, J. 1982. Distribution and ecological characteristics of trees and shrubs of British Columbia. Vancouver, BC: University of British Columbia, Department of Botany and Faculty of Forestry. 131 p. 
42. Kruckeberg, A. R. 1982. Gardening with native plants of the Pacific Northwest. Seattle: University of Washington Press. 252 p. 
43. Kuchler, A. W. 1964. Manual to accompany the map of potential vegetation of the conterminous United States. Special Publication No. 36. New York: American Geographical Society. 77 p. 
44. Lackschewitz, Klaus. 1991. Vascular plants of west-central Montana--identification guidebook. Gen. Tech. Rep. INT-227. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station. 648 p. 
45. Lanner, Ronald M. 1983. Trees of the Great Basin: A natural history. Reno, NV: University of Nevada Press. 215 p. 
46. Little, Elbert L., Jr. 1979. Checklist of United States trees (native and naturalized). Agric. Handb. 541. Washington, DC: U.S. Department of Agriculture, Forest Service. 375 p. 
47. Lyon, L. Jack; Stickney, Peter F. 1976. Early vegetal succession following large northern Rocky Mountain wildfires. In: Proceedings, Tall Timbers fire ecology conference and Intermountain Fire Research Council fire and land management symposium; 1974 October 8-10; Missoula, MT. No. 14. Tallahassee, FL: Tall Timbers Research Station: 355-373. 
48. Martin, Jon Randall. 1989. Vegetation and environment in old growth forests of northern southeast, Alaska: a plant association classification. Tempe, AZ: Arizona State University. 221 p. Thesis. 
49. Means, Joseph E. 1990. Tsuga mertensiana (Bong.) Carr. mountain hemlock. In: Burns, Russell M.; Honkala, Barbara H., technical coordinators. Silvics of North America. Volume 1. Conifers. Agric. Handb. 654. Washington, DC: U.S. Department of Agriculture, Forest Service: 623-634. 
50. Minore, Don. 1979. Comparative autecological characteristics of northwestern tree species--a literature review. Gen. Tech. Rep. PNW-87. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Forest and Range Experiment Station. 72 p. 
51. Munz, Philip A. 1973. A California flora and supplement. Berkeley, CA: University of California Press. 1905 p. 
52. Neiland, Bonita J. 1971. The forest-bog complex of southeast Alaska. Vegetatio. 22: 1-64. 
53. Orme, Mark L.; Ragain, Dale P. 1982. Livestock and big game summer forage following logging. In: Wildlife-livestock relationship symposium: Proceedings; [Date of conference unknown]; Coure d' Alene, ID. Moscow, ID: University of Idaho, Forest, Wildlife and Range Experiment Station: 607-614. 
54. Owens, John N. 1984. Bud development in mountain hemlock (Tsuga mertensiana). II. Cone-bud differentiation and predormancy development. Canadian Journal of Botany. 62: 484-494. 
55. Owens, John N. 1986. Cone and seed biology. In: Shearer, Raymond C., compiler. Proceedings--conifer tree seed in the Inland Mountain West symposium; 1985 August 5-6; Missoula, MT. Gen. Tech. Rep. INT-203. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Research Station: 14-31. 
56. Owens, John N.; Molder, Marje. 1975. Sexual reproduction of mountain hemlock (Tsuga mertensiana). Canadian Journal of Botany. 53: 1811-1826. 
57. Pfister, Robert D.; Kovalchik, Bernard L.; Arno, Stephen F.; Presby, Richard C. 1977. Forest habitat types of Montana. Gen. Tech. Rep. INT-34. Ogden, UT: U.S. Department of Agriculture, Forest Service, Intermountain Forest and Range Experiment Station. 174 p. 
58. Pielou, E. C. 1988. The world of northern evergreens. Ithaca, NY: Cornell University Press. 174 p. 
59. Preston, Richard J., Jr. 1948. North American trees. Ames, IA: The Iowa State College Press. 371 p. 
60. Raunkiaer, C. 1934. The life forms of plants and statistical plant geography. Oxford: Clarendon Press. 632 p. 
61. Reynolds, Keith M. 1990. Preliminary classification of forest vegetation of the Kenai Penninsula, Alaska. Res. Pap. PNW-RP-424. Portland, OR: U.S. Department of Agriculture, Forest Service, Pacific Northwest Research Station. 67 p. 
62. Ruth, Robert H. 1974. Tsuga (Endl.) Carr. hemlock. In: Schopmeyer, C. S., ed. Seeds of woody plants in the United States. Agric. Handb. 450. Washington, DC: U.S. Department of Agriculture, Forest Service: 819-827. 
63. Scagel, Rob; Green, Bob; Von Hahn, Helmar; Evans, Richard. 1989. Exploratory high elevation regeneration trials in the Vancouver forest region: 10-year species performance of planted stock. FRDA Report 098. Victoria, BC: BC Ministry of Forests, Research Branch. 40 p. 
64. Schmidt, Wyman C.; Larson, Milo. 1989. Silviculture of western inland conifers. In: Burns, Russell M., compiler. The scientific basis for silvicultural and management decisions in the National Forest System. Gen. Tech. Rep. WO-55. Washington, DC: U.S. Department of Agriculture, Forest Service: 40-58. 
65. Spalt, Karl W.; Reifsnyder, William E. 1962. Bark characteristics and fire resistance: a literature survey. Occas. Paper 193. New Orleans, LA: U.S. Department of Agriculture, Forest Service, Southern Forest Experiment Station. 19 p. In cooperation with: Yale University, School of Forestry. 
66. Turner, Nancy J. 1988. Ethnobotany of coniferous trees in Thompson and Lillooet Interior Salish of British Columbia. Economic Botany. 42(2): 177-194. 
67. U.S. Department of Agriculture, Forest Service, Division of Timber Management, Region 1. 1970. Reference material: Daubenmire habitat types. Unpublished report on file at: U.S. Department of Agriculture, Forest Service, Intermountain Research Station, Fire Sciences Laboratory, Missoula, MT. 17 p. [+ Appendices]. 
68. U.S. Department of Agriculture, Forest Service, Alaska Region. [n.d.]. Preliminary forest plant associations of the Stikine Area, Tongass National Forest. R10-TP-72. Portland, OR. 126 p. 
69. U.S. Department of Agriculture, Soil Conservation Service. 1982. National list of scientific plant names. Vol. 1. List of plant names. SCS-TP-159. Washington, DC. 416 p. 
70. Van Dersal, William R. 1938. Native woody plants of the United States, their erosion-control and wildlife values. Washington, DC: U.S. Department of Agriculture. 362 p. 
71. Viereck, Leslie A.; Little, Elbert L., Jr. 1972. Alaska trees and shrubs. Agric. Handb. 410. Washington, DC: U.S. Department of Agriculture, Forest Service. 265 p. 
72. Weetman, G.; Vyse, A. 1990. Natural regeneration. In: Lavender, D. P.; Parish, R.; Johnson, C. M.; [and others], eds. Regenerating British Columbia's forests. Vancouver, BC: University of British Columbia Press: 118-129. 
73. Douglas, George W.; Ballard, T. M. 1971. Effects of fire on alpine plant communities in the North Cascades, Washington. Ecology. 52(6): 1058-1064. 
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