Alpine Hemlock

The Tsuga Mertensiana is commonly known as Alpine Hemlock, Black Hemlock, Hemlock Spruce, as well as Mountain Hemlock

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Growing Regions

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 [32].

     

General Information

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 [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 [32].
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 [49].  Published classifications identifying mountain
hemlock as a dominant or codominant are as follows:

Forest types of the North Cascades National Park Service complex [1].
Preliminary plant associations of the Southern Oregon Cascade Mountain
  Province [5].
Preliminary plant associations of the Siskiyou Mountain Province [6].
Plant association and management guide for the Pacific silver fir zone [12].
Forest habitat types of northern Idaho: A second approximation [15].
Classification of montane forest community types in the Cedar River
  drainage of western Washington, U.S.A. [18].
Preliminary forest plant association management guide. Ketchikan area,
  Tongass National Forest [19].
Subalpine plant communities of the western North Cascades, Washington [21].
Alpine and high subalpine plant communities of the North Cascades Range,
  Washington and British Columbia [22].
Fire ecology of western Montana forest habitat types [25].
Forest vegetation of the montane and subalpine zones, Olympic Mountains,
  Washington [27].
Natural vegetation of Oregon and Washington [29].
The forest communities of Mount Rainier National Park [30].
Plant associations of south Chiloquin and Klamath ranger districts--
  Winema National forest [37].
Vegetation and environment in old growth forests of northern southeast
  Alaska: a plant association classification [48].
Forest habitat types of Montana [57].
Preliminary classification of forest vegetation of the Kenai Peninsula,
  Alaska [61].
Preliminary forest plant associations of the Stikine area, Tongass
  National Forest [68].

• More Alpine Hemlock Information

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