Pseudotsuga menziesii var. menziesii, commonly known as coast Douglas-fir, Pacific Douglas-fir, Oregon pine, or Douglas spruce, is a very tall evergreen conifer, being a variety of P. menziesii (Douglas-fir). It is native to western North America and is used as timber.
Description Coast Douglas-fir is the fourth tallest conifer and fifth tallest of all currently living trees in the world (after Sitka spruce). Currently, coast Douglas-fir trees 60–75 metres (197–246 ft) or more in height and 1.5–2 m (4 ft 11 in – 6 ft 7 in) in diameter are common in old growth stands, while maximum heights of 100–120 m (330–390 ft) and diameters up to 4.5–5.5 m (15–18 ft) have been documented. The tallest known living specimen is 99.82 m (327 ft 6 in) tall, near Eugene, Oregon, and an over 100.59 m (330 ft 0 in) tall specimen at Hand Creek, Siuslaw National Forest, Oregon, only recently lost its top. The stoutest is the Queets Fir, 4.85 m (15 ft 11 in) diameter, in the Queets River valley, Olympic National Park, Washington. The tallest specimen ever was probably the Nooksack Giant, with a height of 142 m (466 ft) as measured by tape after the tree was cut down. Coast Douglas-fir commonly lives more than 500 years and occasionally more than 1,000 years. The bark on young trees is thin, smooth, gray, and contains numerous resin blisters. On mature trees, it is thick and corky. The shoots are brown to olive-green, turning gray-brown with age, smooth, though not as smooth as fir shoots, and finely pubescent with short dark hairs. The buds are a very distinctive narrow conic shape, 4–8 mm (3⁄16–5⁄16 in) long, with red-brown bud scales. 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. Unlike the Rocky Mountain Douglas-fir, coast Douglas-fir foliage has a noticeable sweet fruity-resinous scent, particularly if crushed.
The mature female seed cones are pendent, 5–8 cm (2–3+1⁄4 in) long, 2–3 cm (3⁄4–1+1⁄4 in) broad when closed, opening to 4 cm (1+1⁄2 in) broad. They are produced in spring, green at first, maturing orange-brown in the autumn 6–7 months later. The seeds are 5–6 mm (3⁄16–1⁄4 in) long and 3–4 mm (1⁄8–3⁄16 in) broad, with a 12–15 mm (1⁄2–9⁄16 in) wing. The male (pollen) cones are 2–3 cm (3⁄4–1+1⁄4 in) long, dispersing yellow pollen in spring. In forest conditions, old individuals typically have a narrow, cylindric crown beginning 20–40 metres (66–131 ft) above a branch-free trunk. Self-pruning is generally slow and trees retain their lower limbs for a long period. Young, open-grown trees typically have branches down to near ground level. It often takes 70–80 years for the trunk to be clear to a height of 5 m (16 ft) and 100 years to be clear to a height of 10 m (33 ft). Appreciable seed production begins at 20–30 years in open-grown coast Douglas-fir. Seed production is irregular; over a 5–7 year period, stands usually produce one heavy crop, a few light or medium crops, and one crop failure. Even during heavy seed crop years, only about 25 percent of trees in closed stands produce an appreciable number of cones. Each cone contains around 25 to 50 seeds. Seed size varies; average number of cleaned seeds varies from 70 to 88/g (32,000–40,000 per pound). Seeds from the northern portion of coast Douglas-fir's range tend to be larger than seed from the south.
Distribution and habitat Coast Douglas-fir is native to western North America from west-central British Columbia, Canada, southward to Central California, United States. In Oregon and Washington, its range is continuous from the Cascades crest west to the Pacific coast, including the Pacific Coast Ranges. In California, it is found in the Klamath and California Coast Ranges as far south as the Santa Lucia Mountains, with a small stand as far south as the Purisima Hills, Santa Barbara County. In the Sierra Nevada, it ranges as far south as the Yosemite region. It occurs from near sea level along the coast to 1,800 m (5,900 ft) in the California Mountains. Further inland, coast Douglas-fir is replaced by Rocky Mountain or interior Douglas-fir (P. menziesii var. glauca). Interior Douglas-fir intergrades with coast Douglas-fir in the Cascades of northern Washington and southern British Columbia.
Ecology
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