Western hemlock

Silhouette - western hemlock
  • Latin name: Tsuga heterophylla (Raf.) Sarg.
  • French name: Pruche de l'Ouest
  • Synonym(s): Pacific hemlock
  • Taxonomic Serial Number: 183400
Description

Leaves

  • Twig with lateral buds (left); needle cross section (right) - western hemlock

Form

  • Sides parallel, flat, finely toothed
  • Length variable
  • Blunt-tipped
  • Needles clearly arranged in 2 ranks, with a few shorter ones on the upper side pressed against the twig

Length

  • 5–20 mm

Colour

  • Upper surface shiny dark green and grooved
  • Whitened on lower surface with ill-defined lines of white dots on either side of the midvein

Buds

Form

  • Globular

Length

  • 2–3 mm

Twigs

  • Twig with needles and open seed cone - western hemlock

Form

  • Slender, hairy

Colour

  • Brownish-grey

Seed cones (mature)

  • Cone scale; outer surface with bract (left), inner surface with winged seed (center), winged seed inner surface and seed (right) - western hemlock

Form

  • Ovoid, blunt-tipped
  • Short-stalked

Length

  • 20–25 mm

Colour

  • Golden brown

Structure

  • Scales rectangular
  • Tip rounded
  • Margin smooth or faintly toothed

Timing

  • Cones open in autumn
  • Seeds shed gradually
  • Cones may stay on the tree for 1 or 2 years

Seedlings

Form

  • Seedlings commonly found on rotten logs, or in partially decomposed forest litter

Bark

Form

  • Smooth when young, becoming deeply furrowed with flat-topped scaly ridges

Colour

  • Reddish-brown when young, becoming darker

Wood

Texture

  • Moderately light, fairly hard and strong

Colour

  • Whitish to dull light brown

Morphology

  • Little contrast between sapwood and heartwood

Uses

  • Wood pulp, lumber
  • Siding, flooring, plywood, railway ties, boxes, and crates

Size

Height

  • To 50 m

Diameter

  • To 120 cm, occasionally larger

Maximum age

  • 500 years

Tree form

  • Silhouette - western hemlock

Forest-grown

Trunk

  • Lower trunk long, branch-free

Crown

  • Open, conical, becoming irregular with age
  • Leading shoot oblique, bending away from prevailing wind
  • Principal branches coarse, spreading horizontally from the trunk
  • Drooping sprays of branchlets giving a graceful appearance

Root system

  • Shallow, wide-spreading

Habitat

Site

  • Varied soils and in the mountains up to 1500 m

Light tolerance

  • Very shade-tolerant
  • Regenerates well under a closed canopy
  • Thrives in full light and in shade

Associated species

  • Grows in pure stands, but usually mixed with western redcedar, Douglas-fir, grand fir, black cottonwood, and red alder

Range

Pacific Coast, adjacent islands

Insects and diseases

Insects and diseases that are found most frequently and/or that cause the most damage in our Canadian forests.

Photos
  • Western hemlock
  • Western hemlock
  • Western hemlock
Distribution map
Distribution map - western hemlock
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