Tsuga mertensiana

Scientific name: Tsuga mertensiana  (Bongard) Carrière  1867

Synonyms: Abies mertensiana (Bong.) Lindl. & Gordon, Abies pattoniana J.Jeffrey ex Balf., Abies pattonii J.Jeffrey ex Gordon, Abies taxifolia J.Jeffrey ex Gordon, Abies williamsonii Newb., Hesperopeuce mertensiana (Bong.) Rydb., Hesperopeuce pattoniana (J.Jeffrey ex Balf.) Lemmon, Picea californica Carrière, Picea mertensiana Gordon, Pinus mertensiana Bong., Pinus pattoniana (J.Jeffrey ex Balf.) Parl., Tsuga pattoniana (J.Jeffrey ex Balf.) Engelm., Tsuga pattonii Coville, Tsuga williamsonii (Newb.) de Vos

Common names: Mountain hemlock

Description

Tree to 40(-45) m tall, or shrubby at the alpine line, with straight trunk to 1.5(-2) m in diameter. Bark deeply furrowed, scaly, dark red-brown to gray-brown. Crown narrowly conical, broadening somewhat with age. Twigs densely hairy to hairless. Winter buds pointed, 2-3 mm long. Needles plumper than in other hemlocks, spreading all around the twigs rather than largely in two ranks, more even in length, (0.5-)1-2(-3) cm long, parallel sided, with smooth edges, the tip bluntly pointed, waxy gray-green and with stomatal lines above as well as beneath. Pollen cones about 10 mm long, purple maturing yellow. Seed cones purple before maturity, ripening brown, (2-)3-6(-8) cm long, opening to 1.2-2.5(-3.3) cm wide, the seed scales bending backward, 8-13(-18) mm long. Seed body 3-5 mm long, the wing 5-8 mm longer.

Pacific region of western North America, from the Kenai Peninsula of Alaska to the southern Sierra Nevada of California and in the Rocky Mountain region from southern British Columbia to northern Idaho and northwestern Montana. Coastal (in the north) and montane forests to the alpine tree line; 0-2,400(-3,350) m.

Conservation Status

Red List Category & Criteria: Least Concern

(The vast range of this species and its minor importance as a timber tree ensures its status as Least Concern well into the future)

References

Farjon, A. (2010). A Handbook of the World's Conifers. Koninklijke Brill, Leiden.

Eckenwalder, J.E. (2009) Conifers of the World: The Complete Reference. Timber Press, Portland.

IUCN Red List of Threatened Species, International Union for Conservation of Nature and Natural Resources. Cambridge, UK /Gland, Switzerland

Copyright © Aljos Farjon, James E. Eckenwalder, IUCN, Conifers Garden. All rights reserved.