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Douglas-fir is a huge and stately evergreen conifer, the largest member of the pine family, in fact. Specimens more than 300 ft (91.4 m) tall with trunk diameters exceeding 15 ft (4.6 m) are known. The National Champion, in Oregon, is 329 ft (100.3 m) tall. Some of the larger trees are believed to be over a thousand years old. The tall, straight trunk can be free of branches for a third of its length. The bark on young trees is smooth and ashy gray; that on mature trees is reddish brown and broken into longitudinal plates; really large trees can have bark more than 12 in (30.5 cm) thick. The grayish green needles are flattened, quite soft, about 1 in (2.5 cm) long, and arranged all around the twigs like a bottle brush. The cones are oval and pendulous, 2-4 in (5.1-10.2 cm) long and each scale has a conspicuous three-pointed bract that gives the cone an overall spiny look. These trident shaped bracts are unique to the Douglas-firs. Pseudotsuga menziesii var. glauca, the Rocky Mountain Douglas-fir, is a smaller tree with smaller cones, bluish needles and occurs at higher elevations than the coastal variety (var. menziesii). There are several cultivars selected for their slow growth rates and small stature; many never exceed 60 ft (18.3 m) in height. 'Fastigiata' has crowded, upright pointing branches. 'Pendula' is a weeping cultivar with branches that hang in flat panes. 'Fletcheri' is a spreading dwarf cultivar that gets only 6 ft (1.8 m) tall.
Rocky Mountain Douglas-fir grows naturally throughout the Rocky Mountains from British Columbia to northern Mexico. The coastal variety grows west of the mountain ranges from British Columbia to central California. One of the most abundant trees in western North America, Douglas-firs grow from sea level to 10,000 ft (304.8 m), and in climates that get just 15 in (38.1 cm) of precipitation annually, to climates that average more than 100 in (254 cm) of precipitation a year. It often grows in pure to nearly pure stands. Douglas-fir is a widely grown and very popular ornamental in Great Britain. It has been planted in New Zealand as a timber crop and is now considered an invasive weed there.
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Features Douglas-fir was first discovered in 1791 by the physician and botanist, Archibald Menzies, who is honored in the botanical name. It was introduced to England in 1827 by the Scot, David Douglas, who is honored by the common name. There are only five species in the genus. Pseudotsuga means "false hemlock"; they differ from the true hemlocks (Tsuga) in having hanging, rather than erect, cones. Bigcone Douglas-fir (P. macrocarpa) occurs naturally only in cool mountain canyons in a small area of southern California. The other three species of Douglas-firs occur in eastern Asia. Steve Christman 1/18/01; updated 12/2/03, 11/1/06
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