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|Coast Douglas firs in Marysville, Washington|
Pseudotsuga menziesii, commonly known as Douglas fir or Douglas-fir, is an evergreen conifer species native to western North America. One variety, the coast Douglas fir, grows along the Pacific Ocean from central British Columbia south to central California. A second variety, the Rocky Mountain Douglas fir, grows in the Rocky Mountains from British Columbia south to Mexico. The tree is dominant in western Washington. It is extensively used for timber, worldwide.
The common name honors David Douglas, a Scottish botanist and collector who first reported the extraordinary nature and potential of the species. The common name is misleading since it is not a true fir, i.e., not a member of the genus Abies. For this reason the name is often written as Douglas-fir (a name also used for the genus Pseudotsuga as a whole).
The specific epithet, menziesii, is after Archibald Menzies, a Scottish physician and rival naturalist to David Douglas. Menzies first documented the tree on Vancouver Island in 1791. Colloquially, the species is also known simply as Doug-fir or as Douglas pine (although the latter common name may also refer to Pinus douglasiana).
Douglas firs are medium-size to extremely large evergreen trees, 20–100 metres (70–330 ft) tall (although only coast Douglas firs reach such great height). The leaves are flat, soft, linear, 2–4 centimetres (0.8–1.6 in) long, generally resembling those of the firs, occurring singly rather than in fascicles; they completely encircle the branches, which can be useful in recognizing the species. As the trees grow taller in denser forest, they lose their lower branches, such that the foliage may start high off the ground. Douglas firs in environments with more light may have branches much closer to the ground.
The female cones are pendulous, with persistent scales unlike true firs. They are distinctive in having a long tridentine (three-pointed) bract that protrudes prominently above each scale (it resembles the back half of a mouse, with two feet and a tail).
One variety, coast Douglas fir (Pseudotsuga menziesii var. menziesii), grows in the coastal regions, from west-central British Columbia southward to central California. In Oregon and Washington, its range is continuous from the eastern edge of the Cascades west to the Pacific Coast Ranges and Pacific Ocean. In California, it is found in the Klamath and California Coast Ranges as far south as the Santa Lucia Range, with a small stand as far south as the Purisima Hills in 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) above sea level in the mountains of California.
Further inland, coast Douglas fir is replaced by another variety, 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, and from there ranges northward to central British Columbia and southeastward to the Mexican border, becoming increasingly disjunct as latitude decreases and altitude increases. Mexican Douglas fir (P. lindleyana), which ranges as far south as Oaxaca, is often considered a variety of P. menziesii.
Douglas-fir prefers acidic or neutral soils. However, Douglas fir exhibits considerable morphological plasticity, and on drier sites coast Douglas fir will generate deeper taproots. Interior Douglas fir exhibits even greater plasticity, occurring in stands of interior temperate rainforest in British Columbia, as well as at the edge of semi-arid sagebrush steppe throughout much of its range, where it generates even deeper taproots than coast Douglas fir is capable.
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. Red tree voles may also be found in immature forests if Douglas fir is a significant component. This animal nests almost exclusively in the foliage of Douglas fir trees. Nests are located 2–50 metres (5–165 ft) above the ground. The red vole's diet consists chiefly of Douglas fir needles. A parasitic plant sometimes utilizing P. menziesii is Douglas-fir dwarf mistletoe (Arceuthobium douglasii).
The leaves are also used by the woolly conifer aphid Adelges cooleyi; this 0.5 mm long sap-sucking insect is conspicuous on the undersides of the leaves by the small white "fluff spots" of protective wax that it produces. It is often present in large numbers, and can cause the foliage to turn yellowish from the damage in causes. Exceptionally, trees may be partially defoliated by it, but the damage is rarely this severe. Among Lepidoptera, apart from some that feed on Pseudotsuga in general (see there) the gelechiid moths Chionodes abella and C. periculella as well as the cone scale-eating tortrix moth Cydia illutana have been recorded specifically on P. menziesii.
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. Adapted to a moist, mild climate, it grows larger and faster than Rocky Mountain Douglas fir. Associated trees include western hemlock, Sitka spruce, sugar pine, western white pine, ponderosa pine, grand fir, coast redwood, western redcedar, California incense-cedar, Lawson's cypress, tanoak, bigleaf maple and several others. Pure stands are also common, particularly north of the Umpqua River in Oregon.
The shade-intolerance of Douglas fir plays a large role in the forest succession of lowland old growth rainforest communities of the Pacific Northwest. While mature stands of lowland old-growth rainforest contain many western hemlock (Tsuga heterophylla) seedlings, and some western redcedar (Thuja plicata) seedlings, Douglas fir dominated stands contain almost no Douglas fir seedlings. This seeming contradiction occurs because Douglas firs are intolerant of deep shade and rarely survive for long within the shaded understory. When a tree dies in a mature forest the canopy opens up and sunlight becomes available as a source of energy for new growth. The shade-tolerant western hemlock seedlings that sprout beneath the canopy have a head-start on other seedlings. This competitive advantage allows the western hemlock to grow rapidly into the sunlight, while other seedlings still struggle to emerge from the soil. The boughs of the growing western hemlock limit the sunlight for smaller trees and severely limit the chances of shade-intolerant trees, such as the Douglas fir. Over the course of centuries, western hemlock typically come to dominate the canopy of an old-growth lowland rainforest.
Douglas firs are seral trees in temperate rainforest, and possess thicker bark and a somewhat faster growth rate than most other climax trees of the area, such as the western hemlock and western redcedar. This quality often gives Douglas firs a competitive advantage when the forest experiences a major disturbance such as fire. Periodically, portions of a Pacific Northwest lowland forest may be burned by wildfire, may be logged, or may be blown down by a wind storm. These types of disturbances allow Douglas fir to regenerate in openings, and low-intensity fires often leave Douglas fir trees standing on drier sites, while less drought- and fire-tolerant species are unable to get established.
Conifers dominate the climax forests of the coast Douglas fir. All of the climax conifers that grow alongside it can live for centuries, with a few species capable of living for over a millennium. Forests that exist on this time scale experience the type of sporadic disturbances that allow mature stands of Douglas fir to establish themselves as a persistent element within a mature old-growth forest. When old growth forests survive in a natural state, they often look like a patchwork quilt of different forest communities. Western hemlock typically dominate oldgrowth rainforests, but contain sections of Douglas firs, redcedar, alder, and even coast redwood forests on their southern extent, near the Oregon and California border, while Sitka spruce increases in frequency with latitude.
The logging practices of the last 200 years created artificial disturbances that caused Douglas firs to thrive. The Douglas fir's useful wood and its quick growth make it the crop of choice for many timber companies, which typically replant a clear-cut area with Douglas fir seedlings. The high-light conditions that exist within a clear-cut also naturally favor the regeneration of Douglas fir. Because of clear-cut logging, almost all the Pacific Northwest forests not strictly set aside for protection are today dominated by Douglas fir, while the normally dominant climax species, such as western hemlock and western redcedar are less common. On drier sites in California, where Douglas fir behaves as a climax species in the absence of fire, the 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.
This plant has ornamental value in large parks and gardens.
Away from its native area, it is also extensively used in forestry as a plantation tree for timber in Europe, New Zealand, Chile and elsewhere. It is also naturalised throughout Europe, Argentina and Chile (called Pino Oregón), and in New Zealand sometimes to the extent of becoming an invasive species (termed a wilding conifer) subject to control measures.
As of 1995[update], coast Douglas fir was the second-tallest conifer in the world (after coast redwood). Extant coast Douglas fir trees 60–75 m (195–245 ft) or more in height and 1.5–2 m (4.9–6.6 ft) in diameter are common in old growth stands, and maximum heights of 100–120 m (330–395 ft) and diameters up to 4.5–5.5 m (15–18 ft) have been documented. The tallest living specimen is the "Doerner Fir", previously known as the Brummit Fir, 99.8 m (327.3 ft) tall, at East Fork Brummit Creek in Coos County, Oregon, the stoutest is the "Queets Fir", 4.85 m (15 ft 11 in) in diameter, in the Queets River valley of Olympic National Park in Washington. Douglas firs commonly live more than 500 years and occasionally more than 1,000 years.
The tallest well-documented conifer was 393 feet (120 m), the Mineral Tree (Mineral, Washington), a coast Douglas fir, measured in 1924 by Dr. Richard E. McArdle, former chief of the U.S. Forest Service. The volume of that tree was 515 cubic metres (18,190 cu ft). 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.
Many poorly-attested reports of taller individuals may be found.
- A tree cut down in 1902 at Lynn Valley on the north shore of Vancouver, British Columbia, was reported to have measured 415 feet (126 m) in height, and 14.25 feet (4.34 m) in diameter.
- A Douglas fir felled in 1897 at Loop's Ranch in Whatcom County, Washington reportedly measured 465 feet (142 m) in height, 34 feet (10 m) in circumference at the butt, and 220 feet (67 m) to the first branch. With a volume of 96,345 board feet (227.35 m3), this tree was estimated to be 480 years old.
The tallest tree in the United Kingdom is a coast Douglas fir. The tree, growing in Reelig Glen by Inverness stands at a height of 217.10 ft (66.4m) and now exceeds the height of the previously measured Douglas fir called Dughall Mor which stands at 210ft (64m) and which was measured in 2005 by Tony Kirkham and Jon Hammerton from the Royal Botanic Gardens, Kew, the late Jim Paterson from The Tree Register and David Jardine of the Forestry Commission.
- Farjon, A. (2013). "Pseudotsuga menziesii". IUCN Red List of Threatened Species. IUCN. 2013: e.T42429A2979531. doi:10.2305/IUCN.UK.2013-1.RLTS.T42429A2979531.en. Retrieved 13 November 2016.
- "Douglas-fir (Pseudotsuga)". Common Trees of the Pacific Northwest. Oregon State University. Retrieved March 28, 2013.
- Dictionary of Upriver Halkomelem, Volume I, pp. 213. Galloway, Brent Douglas.
- Carder, Al (1995). Forest Giants of the World Past and Present. pp. 3–4.
- James R. Griffin (September 1964). "A New Douglas-Fir Locality in Southern California". Forest Science: 317–319. Retrieved December 31, 2010.
- James R. Griffin; William B. Critchfield (1976). The Distribution of Forest Trees in California USDA Forest Service Research Paper PSW – 82/1972 (PDF). Berkeley, California: USDA Forest Service. p. 114. Retrieved 2015-05-03.
- Barton, G.M. (1972). "New C-methylflavanones from Douglas fir". Phytochemistry. 11 (1): 426–429. doi:10.1016/S0031-9422(00)90036-0.
- C. Michael Hogan (2008), Douglas-fir: Pseudotsuga menziesii, globalTwitcher.com, ed. Nicklas Strõmberg Archived June 4, 2009, at the Wayback Machine.
- "Pseudotsuga menziesii". Royal Horticultural Society.
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- "Pseudotsuga menziesii var. menziesii". The Gymnosperm Database. Retrieved March 17, 2013.
This was the preferred species for Hawaiian war canoes. The Hawaiians, of course, did not log the trees; they had to rely on driftwood.
- Carder, A. (1995). Forest Giants of the World: Past and Present. Ontario: Fitzhenry and Whiteside. pp. 1–10. ISBN 978-1-55041-090-7.
- McArdle, Richard E. (1930). The Yield of Douglas Fir in the Pacific Northwest. United States Department of Agriculture. Technical Bulletin No. 201. p. 7. Retrieved 15 October 2016.
- Carder, Forest Giants pp. 1-10
- Vaden, M D. "Doerner Fir - Tallest Douglas Fir". Retrieved 14 October 2016.
- "Pseudotsuga menziesii var. menziesii". Gymnosperm Database. Retrieved March 17, 2013.
- Forest Giants of the World Past and Present by Al Carder 1995, pg. 3-4.
- "Richard McArdle Bio, USFS History, Forest History Society". Foresthistory.org. Retrieved 2011-03-09.
- Kinver, Mark (August 13, 2008). "Water's the limit for tall trees". BBC News.
- "Douglas-fir: A 350-foot-long Drinking Straw is As Long As It Gets". Oregon State University. August 11, 2008. Archived from the original on October 8, 2008.
- Parminter, John (January 1996). "A Tale of a Tree" (PDF). British Columbia Forest History Newsletter. Forest History Association of British Columbia. pp. 3–4. Retrieved February 14, 2014.
- "Topics of The Times" (PDF). The New York Times. March 7, 1897. Retrieved February 14, 2014.
- Meehans' Monthly: A Magazine of Horticulture, Botany and Kindred Subjects Published by Thomas Meehan & Sons, 1897, p. 24
- "This Tree Might Reach to China". The Morning Times. Washington, D.C. February 28, 1897. p. 19. Retrieved February 14, 2014.
- Judd, Ron (September 4, 2011). "Restless Native: Giant logged long ago but not forgotten". The Seattle Times. Retrieved September 7, 2011.
- "The Trees That Made Britain". BBC Wales.
- Emily K. Brock, Money Trees: The Douglas Fir and American Forestry, 1900–1944. Corvallis, OR: Oregon State University Press, 2015.
- Uchytil, Ronald J. (1991). "Pseudotsuga menziesii var. menziesii". Fire Effects Information System (FEIS). U.S. Department of Agriculture (USDA), Forest Service (USFS), Rocky Mountain Research Station, Fire Sciences Laboratory – via https://www.fs.fed.us/database/feis/.
|Wikimedia Commons has media related to:|
- "Pseudotsuga menziesii". Natural Resources Conservation Service PLANTS Database. USDA.
- Calflora Database: Pseudotsuga menziesii (Douglas fir)
- Conifers.org: Pseudotsuga menziesii
- Arboretum de Villardebelle – cone photos
- Humboldt State University — Photo Tour: Douglas-fir, Pseudotsuga menziesii — Institute for Redwood Ecology
- Pseudotsuga menziesii - information, genetic conservation units and related resources. European Forest Genetic Resources Programme (EUFORGEN)