Douglas-fir

Silhouette - Douglas-fir
  • Latin name: Pseudotsuga menziesii (Mirb.) Franco var. menziesii
  • French name: Douglas vert
  • Synonym(s): Green Douglas-fir , Douglas , common Douglas-fir , coast Douglas-fir
  • Taxonomic Serial Number: 183426
  • NA6 , C7
Description

Leaves

  • Twig and needles - Douglas-fir

Form

  • Needles evergreen
  • Remaining on tree for 5–8 years
  • Flat, flexible, grooved above
  • Often sharp-pointed
  • Narrowed at the base into a slender short stalk, set on a leaf-cushion
  • Needles spirally arranged along the twig
  • On horizontal branches, spreading out from the sides in 2 ranks or spreading out from 3 sides and moderately parted on the upper side
  • Midvein prominent
  • 2 resin ducts visible in cross-section
  • Slight apple odour when crushed

Length

  • 2–3 cm

Colour

  • Upper surface bright yellowish-green
  • Lines of white dots on lower surface

Buds

Form

  • Terminal bud narrowly conical, sharp-pointed
  • A small cluster of lateral buds occurs just below the terminal bud, separated by a few needles
  • Other lateral buds scattered along the twig

Length

  • Up to 10 mm

Colour

  • Many shiny reddish-brown overlapping scales

Twigs

  • Twig terminal - Douglas-fir

Form

  • Moderately stout and flexible, hairy
  • Leaf-cushion a low ridge of bark darkened at the forward end
  • After the needles have fallen, the branchlets show slightly raised oval scars on the leaf-cushions

Colour

  • Greenish-brown becoming greyish-brown

Seed cones (immature)

Form

  • Conelets borne in the upper part of the crown, in leaf axils near the forward end of previous year’s twig
  • Seed-cone buds are larger than shoot buds

Length

  • About 30 mm

Colour

  • At pollination, green to purple to red

Structure

  • Oblong at pollination
  • Erect, short-stalked, with distinctive 3-pronged bracts extending beyond the scales and partially obscuring them
  • After pollination, the cone stalk bends downward

Timing

  • Mature in late summer of first season

Pollen cones

Form

  • Cylindrical to conical, fleshy, catkin-like, pendulous
  • Pollen-cone buds are paler than shoot buds

Length

  • 10–20 mm

Colour

  • Yellow to orange-red

Structure

  • Borne in the upper-middle, middle, and lower parts of the crown, in leaf axils of previous year’s twigs

Timing

  • Pollination takes place in early spring as new leafy shoots start to elongate; cones then wither and fall away

Seed cones (mature)

  • Winged seed (left); cone (right) - Douglas-fir

Form

  • Narrowly ovoid
  • Pendulous on stout stalks

Length

  • 6–9 cm

Colour

  • Yellowish-brown to purplish-brown

Structure

  • Scales numerous, broad, rounded, leathery
  • Bracts prominent, 3-pronged, longer than the scales

Timing

  • Seeds shed throughout fall, winter, and spring
  • Cones drop intact after seed dispersal

Seeds

Form

  • Somewhat triangular

Length

  • Seed 5–7 mm
  • Seed wing 15–18 mm

Colour

  • Seed shiny reddish brown

Seedlings

  • Seedling development; cotyledon stage (left), end of 1st season (right) - Douglas-fir

Form

  • Newly germinated seedlings with a stalk surmounted by a whorl of 5–10 upcurved cotyledons with smooth edges
  • Needles form above the cotyledons, clustered at first, later spreading along the new shoot

Length

  • Seedlings about 4 cm
  • Cotyledons about 2 cm

Colour

  • Cotyledons green

Bark

Form

  • Smooth, thin, resin-blistered when young
  • Becoming deeply furrowed with irregular, broad ridges
  • Up to 30 cm thick

Colour

  • Grey when young, becoming dark reddish-brown

Wood

Texture

  • Moderately heavy and hard
  • Exceptionally strong

Colour

  • Heartwood reddish-brown
  • Sapwood yellowish-white

Morphology

  • Marked contrast between earlywood and latewood
  • Resin ducts present

Uses

  • Wood pulp, lumber
  • Used for structural purposes
  • Shipbuilding, laminated beams, interior and exterior finishings
  • Boxes, railway ties, piling and decking for marine structures

Size

Height

  • To 60 m

Diameter

  • To 200 cm

Maximum age

  • 500 years

Tree form

  • Silhouette - Douglas-fir

Forest-grown

Trunk

  • In old trees, long, branch-free, cylindrical

Crown

  • In old trees, short, columnar, flat-topped
  • In young trees, narrowly conical crowns often extend to the ground
  • Principal branches in irregular whorls at the annual nodes, lesser branches in between
  • Dead branches may remain on the trunk for years

Root system

  • Strong, wide-spreading

Habitat

Site

  • Varied soils, best growth on deep, well-drained, sandy loams and where moisture in the soil and atmosphere is plentiful
  • Commonly a pioneer species that regenerates after forest fires, logging, and other disturbances

Light tolerance

  • Requires some shade in first year but then thrives in sunlight
  • Less shade-tolerant than its associates

Associated species

  • Western hemlock, amabilis fir, western redcedar, and grand fir

Range

Vancouver Island and the Pacific coast from central British Columbia to California

Insects and diseases

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

Photos
  • Douglas-fir
  • Douglas-fir
  • Douglas-fir
  • Douglas-fir
  • Douglas-fir
Date modified: