Tsuga heterophylla
(Western Hemlock)
[(Raf.) Sarg.]

Class: Pinopsida
Order: Pinatae
Family: Pinaceae
Family Description: Pine
Key Characteristics:
Also known as Western, Pacific, or Lowland Hemlock.
  • branches and branchlets sweep downward;
  • young branches are clothed in a vestiture of short and long pubescence of multicellular trichomes
  • staminate cones 3-4 mm long, yellow: ovulate cones brown at maturity, 1.5-2.5 cm long with puberulent scales which are longer than broad.
  • approximately 4 mm long, with oblong wings 5-6 mm long;
  • cotyledons commonly 3-4.

  • needles 8 to 25 mm long, (noticeably of different lengths on same twigs) almost flat, shiny, yellow-green above with no stomata, whitish beneath due to stomata, rounded, blunt tips form flat sprays because the needles are at right angles to the twigs and branchlets.

General Description:
A tall, slender tree 50-60 m high, with a narrow pyramidal crown (terminal leader droops, forming an arc) and a trunk diameter 1-2.5 m; bark thick, deeply divide into broad, flat ridges; leaves 2-ranked, 6-20 mm long, with 2 light colored bands of stomata beneath; cones purple, ovoid; scales obovate; seeds about 3 mm long, their wings 2-3 times as long. Moist soil, W, Mont. to Alaska, across N. Idaho to Calif.

Along coastlines from Alaska to northern California and a somewhat separate distribution in southeastern British Columbia, northern Idaho and northwestern Montana.

Western Hemlock tolerates and reproduces in deep shade where it is moist, such as in Northern Idaho and coastal regions, thus from sea level to 7,400 feet elevation. Associate species are Mountain Hemlock, Western White Pine, Douglas Fir, Silver Fir, Coastal Redwood, and Sitka Spruce. Common enemies are Hemlock Dwarf Mistletoe, snow and wind, the latter knock over the shallow rooted trees.

Birds and rodents eat the seeds and rabbits, beaver, and deer browse on seedlings, saplings, and even large trees. The lightweight wood is hard, tough and is used for building, construction and pulp. The bark was used by native Americans for tanning leather.

Important State References:
No information available at this time
Photos & information written by Dr. Karl E. Holte,© 2002