menziesii, commonly known as Coast Douglas-fir, Pacific Douglas-fir, Oregon pine, or Douglas spruce, is an evergreen conifer native to western North America from west-central British Columbia, Canada southward to Central California, United States.

The leaves are spirally arranged but slightly twisted at the base to lie in flattish either side of the shoot, needle-like, 2–3.5 cm (3⁄4–1+3⁄8 in) long, green above with no stomata, and with two whitish stomatal bands below.

[9] In forest conditions, old individuals typically have a narrow, cylindric crown beginning 20–40 metres (66–131 ft) above a branch-free trunk.

Even during heavy seed crop years, only about 25 percent of trees in closed stands produce an appreciable number of cones.

[9] Mature or "old-growth" Douglas-fir forest is the primary habitat of the red tree vole (Arborimus longicaudus) and the spotted owl (Strix occidentalis).

Home range requirements for breeding pairs of spotted owls are at least 400 ha (4 square kilometres (990 acres) of old-growth.

Mice, voles, shrews, and chipmunks consumed an estimated 65 percent of a Douglas-fir seed crop following dispersal in western Oregon.

They also eat mature pollen cones, developing inner bark, terminal shoots, and tender young needles.

[9] The coast Douglas-fir variety is the dominant tree west of the Cascade Mountains in the Pacific Northwest, occurring in nearly all forest types, competes well on most parent materials, aspects, and slopes.

Shrub associates in the central and northern part of Coast Douglas-fir's range include vine maple (Acer circinatum), salal (Gaultheria shallon), Pacific rhododendron (Rhododendron macrophyllum), Oregon-grape (Mahonia aquifolium), red huckleberry (Vaccinium parvifolium), and salmonberry (Rubus spectabilis).

In the drier, southern portion of its range shrub associates include California hazel (Corylus cornuta var.

In wet coastal forests, nearly every surface of old-growth coast Douglas-fir is covered by epiphytic mosses and lichens.

This competitive advantage allows western hemlock to rapidly fill the canopy gap, pre-empting other species that may invade, including Douglas-fir.

Douglas-fir is a seral species in the wet forests of western British Columbia, Washington, Oregon, and California.

[12] It has a faster growth rate than most other trees, giving the Douglas-fir a competitive advantage when it overtops slower growing species during re-establishment of the canopy.

[14] Douglas-fir is also particularly well adapted to fires: once they reach around 100 years in age they have thick enough bark that protects the cambium layer of the tree from heat damage.

[15] Fire is increasingly rare northward towards the central coast of British Columbia where Douglas-fir is a minor component of the forest.

On drier sites in California, where Douglas-fir behaves as a climax species in the absence of fire, Douglas-fir has become somewhat invasive following fire suppression practices of the twentieth and twenty-first centuries; it is becoming a dominant species in many oak woodlands, in which it was previously a minor component.

The wood is also made into railroad ties, mine timbers, house logs, posts and poles, flooring, pulp, and furniture.

The largest at 349 cubic metres (12,300 cu ft) is the Red Creek fir in British Columbia, Canada.

Research suggests Douglas fir could grow to a maximum height of between 430 to 476 feet (131 to 145 m), at which point water supply would fail.