Douglas-fir
Douglas-fir is the common name applied to
coniferous trees of the genus
Pseudotsuga in the family
Pinaceae. There are five species, two in western
North America, one in
Mexico and two in eastern
Asia. The douglas-firs gave 19th century botanists problems due to their similarity to various other conifers better known at the time; they have at times been classified in
Pinus,
Picea,
Abies,
Tsuga is a genus of conifers [i] in the family Pinaceae [i]. ...
, and even
Sequoia. Because of the distinctive cones, douglas-firs were finally placed in the new genus
Pseudotsuga by the
French botanist Carrire in 1867.
Encyclopedia
Douglas-fir is the common name applied to
coniferous trees of the genus
Pseudotsuga in the family
Pinaceae. There are five species, two in western
North America, one in
Mexico and two in eastern
Asia. The douglas-firs gave 19th century botanists problems due to their similarity to various other conifers better known at the time; they have at times been classified in
Pinus,
Picea,
Abies,
Tsuga is a genus of conifers [i] in the family Pinaceae [i]. ...
, and even
Sequoia. Because of the distinctive cones, douglas-firs were finally placed in the new genus
Pseudotsuga by the
French botanist Carrière in 1867.
The common name honours David Douglas, the
Scottish botanist who first introduced the tree into cultivation in 1826. Douglas is known for introducing many North American native conifers to
Europe. The hyphen in the common name indicates that douglas-firs are not true firs, i.e. they are not members of the genus
Abies.
The douglas-firs are medium-size to large or very large
evergreen trees, to 20-100 m tall. The
leaves are flat and needle-like, generally resembling those of the
firs. The female
cones are pendulous, with persistent scales , and are distinct in having a long tridentine bract that protrudes prominently above each scale.
Douglas-firs are used as food plants by the
larvae of some
Lepidoptera species including
Autumnal Moth, Bordered White,
The Engrailed, Pine Beauty, Turnip Moth and the
gelechiids Chionodes abella and
Chionodes periculella which have both been recorded on
P. menziesii.
A Californian
Native American myth explains that each of the three-ended bracts are a tail and two tiny legs of the
mice who hid inside the scales of the tree's cones, which was kind enough to be the enduring sanctuary for them during forest fires.
Species and varieties
By far the best-known is the very widespread and abundant
North American species
Pseudotsuga menziesii, a taxonomically complex species divided into two major subspecies ;
Coast Douglas-fir or 'Green Douglas-fir', on the
Pacific coast; and
Rocky Mountain Douglas-fir or 'Interior Douglas-fir', in the interior west of the continent. The latter is in turn divided into two varieties, 'Blue Douglas-fir' or 'Colorado Douglas-fir' in the southern Rocky Mountains, and 'Gray Douglas-fir' or 'Fraser River Douglas-fir' in the northern Rocky Mountains. The species as a whole is generally known as simply 'Douglas-fir', or as 'Common Douglas-fir'; other less widely used names include 'Oregon Douglas-fir', 'Douglas Tree', and 'Oregon Pine'. It can attain heights of 100 m, second only to the
Coast Redwood , and is the
state tree of
Oregon. The specific name,
menziesii, is after
Archibald Menzies, a Scottish physician and
naturalist who first discovered the tree on
Vancouver Island in 1791. Away from its native area, it is also extensively used in
forestry as a
plantation tree for
timber in
Europe,
New Zealand, southern
South America and elsewhere. It is also
naturalised in the
British Isles,
Chile and New Zealand, sometimes to the extent of becoming an
invasive species subject to control measures.
All of the other species are of restricted range and little-known outside of their respective native environments, and even there are often rare and only of very scattered occurrence, occurring in mixed forests; all are listed as being of unfavourable
conservation status.
;North America
;Asia
- Japanese Douglas-fir, Pseudotsuga japonica -
- Chinese Douglas-fir, Pseudotsuga sinensis var. sinensis -
- Narrow-cone Chinese Douglas-fir, Pseudotsuga sinensis var. gaussenii -
- Short-leaf Chinese Douglas-fir, Pseudotsuga sinensis var. brevifolia -
- Yunnan Douglas-fir, Pseudotsuga sinensis var. forrestii - Vulnerable
- Taiwan Douglas-fir, Pseudotsuga sinensis var. wilsoniana - Vulnerable
Uses
Douglas Fir
wood is used for structural applications that require to withstand high loads. Examples include its use for homebuilt
aircraft. Very often, these aircraft were designed to utilise
Sitka Spruce, which is getting increasingly difficult to source in aviation quality grades.
References and external links
- Peng Li & W. T. Adams. Rangewide patterns of allozyme variation in Douglas-fir. Canad. J. Forest Res. 19: 149-161 .
- Images of cones of selected species
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