The Tsuga Mertensiana
is commonly known as Alpine Hemlock
, Black Hemlock
, Hemlock Spruce
, as well as Mountain Hemlock< Go Back
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
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 [32
The currently accepted scientific name for mountain hemlock is Tsuga
mertensiana (Bong.) Carriere [38
]. 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 [49
]. 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) [46
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 .
< Go Back
Much of the information presented here is attributed to:
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 at USDA Forest Service.