Syn: Abies menziesii Mirbel 1825; A. mucronata Rafinesque; A. taxifolia Poiret 1805, not Desfontaines 1804; Pinus taxifolia Lambert 1803, not Salisbury 1796; Pseudotsuga douglasii (Lindley) Carrière; Ps. mucronata (Rafinesque) Sudworth; Ps. taxifolia (Lambert) Britton (Lipscomb 1993). In fact, an extremely complex nomenclatural controversy that surrounded this species from 1800 to 1950, during which time it went through many names that, for one reason or another, were shown to be illegitimate; for a detailer recounting of this controversy, see Reveal [n.d.].
There are two intergrading varieties, menziesii and glauca, sympatric in southern BC and northeastern WA (Lipscomb 1993). A third taxon, Ps. lindleyana, should probably be treated as a variety or subspecies of Ps. menziesii but has not yet been described as such.
Douglas-fir was first described by Archibald Menzies (1754-1842), who discovered it on Vancouver Island during the 1790 voyage by Captain Vancouver to the northeast Pacific Ocean. The species' epithet honors Menzies. The name Douglas-fir commemorates David Douglas, who collected the species along the lower Columbia River in 1824; the seeds that he sent back to England were eagerly received and quickly established the tree as a garden favorite and an important agroforestry species.
"Trees to 90(100) m; trunk to 4.4 m diam.; crown narrow to broadly conic, flattened in age. Twigs slender, pubescent, becoming glabrous with age. Leaves 15-30(-40) × 1-1.5mm, yellow-green to dark or bluish green, apex obtuse to acute. Pollen cones yellow-red. Seed cones 4-10 × 3-3.5 cm. Seeds 5-6 mm, wing longer than seed body" (Lipscomb 1993). Detailed information on pollen, including photomicrography, is provided by Davis (1999).
Canada: British Columbia and Alberta; and United States: Washington, Oregon, California, Idaho, Montana, Wyoming, Nevada, Utah, Colorado, Arizona, New Mexico, and Texas. The coastal variety menziesii occurs from central British Columbia south along the Pacific Coast for about 2,200 km to latitude 34° 44'. The interior variety glauca is found along the Rocky Mountains to southern Arizona and New Mexico, where it merges imperceptibly into the closely related species P. lindleyana of Mexico. "Altitudinal distribution of both varieties of Douglas-fir (menziesii and glauca) increases from north to south, reflecting the effect of climate on distribution of the species. The principal limiting factors are temperature in the north of the range and moisture in the south. Consequently, Douglas-fir is found mainly on southerly slopes in the northern part of its range, and on northerly exposures in the southern part. At high elevations in the southern Rocky Mountains, however, Douglas-fir grows on the sunny slopes and dry rock exposures" (Burns and Honkala 1990). See also Thompson et al. (1999).
See var. menziesii. This is the largest member of the Pinaceae (the second largest, Picea sitchensis, grows with P. menziesii in the coastal forests of NW North America) and larger by far than the other species in the genus.
See var. menziesii.
Many chronologies representing both varieties exist. The species has been used extensively in climate reconstruction and archeological dating. It has also been employed in ecological studies and stable isotope work.
Pseudotsuga menziesii is one of the world's most important timber trees, valued in both the Old and New worlds (Burns and Honkala 1990, Lipscomb 1993). It has been widely planted in New Zealand and is there regarded as an invasive weed.
This is one of the most-studied conifers in the world.
"Douglas-fir ... has been a major component of the forests of western North America since the mid-Pleistocene (Hermann 1985). Although the fossil record indicates that the native range of Douglas-fir has never extended beyond western North America, the species has been successfully introduced in the last 100 years into many regions of the temperate forest zone (Hermann 1987)" (Lipscomb 1993).
Douglas-fir is the state tree of Oregon (Lipscomb 1993).
Both varieties are host to the dwarf mistletoe Arceuthobium douglasii (Hawksworth and Wiens 1996).
Davis, Owen K. 1999. Pollen Grain Morphology Larch. URL=http://geo.arizona.edu/palynology/pid00013.html, accessed 2001.12.11.
Reveal, James R. [no date]. A Nomenclatural Morass. http://www.plantsystematics.org/reveal/pbio/LnC/dougfir.html, accessed 2011.05.20.
Farjon (1990) provides a detailed account, with illustrations.
Last Modified 2012-11-23