Douglas fir lumber characteristics and uses
Blue Douglas-fir Columbian Pine Inland Douglas-fir Colorado real Colorado Douglas-fir Rocky Mountain Douglas-fir Oregon Douglas-fir Oregon pine Douglas-fir (Coast) Coast Douglas-fir Interior Douglas-fir Douglas-fir Colorado pino real
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REGIONS: North America
COUNTRIES: Canada, United States
Although it may be rare at the periphery of its range, Douglas is generally widespread, abundant, and secure globally (Source – The Nature Conservancy – Rank of relative endangerment based primarily on the number of occurrences of the species globally).
The growth range of Douglas fir is reported to include Alberta, British Columbia, Arizona, California, Colorado, Idaho, Minnesota, Montana, New Mexico, Nevada, New York, Oregon, Texas, Utah, Washington, and Wyoming. Coast Douglas-fir is reported to occur in pure stands of vast forests on moist, well drained soils. Rocky Mountain Douglas-fir may occur in pure stands or mixed coniferous forests, and is reported to thrive mainly on rocky soils of mountain slopes. Douglas-fir has also been introduced to other regions in the world, including Great Britain, Ireland, France, Belgium, Germany, New Zealand, and Australia as a source of timber.
Some material from this species is reported to be available from environmentally responsible or sustainably managed sources.
Supplies of Douglas-fir are reported to be adequate since the species grows rapidly, and its growth range extends over a wide area in North America. It is usually priced in the medium to lower range. Remarkably knot-free, strong, and light, Douglas-fir is considered to be one of the best known softwood timbers.
The mature tree is reported to be usually large to very large, attaining a height of 80 to 200 feet (24 to 61 m), and a diameter of 24 to 60 inches (60 to 150 cm). Resinous exudates from any cut on the living tree is reported to leave a coating of yellow rosin as a protection against insect or fungal attack, after the turpentine evaporates.
The sapwood is whitish to pale yellowish, or reddish white in color. It is narrow in the Rocky Mountain type Douglas-fir and can be several inches wide in wood from the Pacific Coast.
There is a great variation in the color of the heartwoodwood. Narrow growth-ring Douglas-fir tends to be yellow or pale reddish yellow in color. Wood with wide annual-rings have wide bands of reddish latewood which give it a color of orange-red or deep-red. There is typically a clean-cut division between the hard, red-brown summerwood bands and the paler, softer, pinkish-yellow springwood.
The grain is usually straight, and may be even or uneven. There is a tendency towards curly or wavy characteristics sometimes. The grain is reported to be displayed best on the large surfaces of rotary-cut veneer from old and large Douglas-fir trees. Contrasting color and texture, as well as irregular, often flame-shaped outlines are also usually present.
The texture is variable depending upon the width of growth rings. Wood with narrow growth rings are quite uniform in texture while those with wider rings are very often uneven textured.
The wood is reported to have very little natural resistance to decay, and should not be used under conditions that promote decay without proper and adequate protection.
Resistance to Abrasion
Douglas fir is reported to be highly suitable for use in areas where wear is a factor because of its hardness.
Pronounced color differences in earlywood and latewood are reported to result in a distinctive grain pattern when logs are rotary peeled into veneers.
The harder latewood can blunt cutting edges.
Cutting resistance can be high depending upon the percentage of latewood.
Douglas fir (Oregon) is reported to have very good planing properties, and works readily with hand and power tools.
The material is reported to turn very well.
Moulding qualities are rated as very good.
Response to boring operations is reported to be very good.
The wood is reported to have very good mortising characteristics.
The material is reported to have very good resistance to splitting in nailing. Nail holding properties are excellent.
Screwing properties are rated as very good, and screw-holding qualities are excellent.
Gluing characteristics are rated as very good.
Douglas-fir is reported to have satisfactory staining qualities. Some stock may develop a slight pinkish to salmon color when finished with some products. Care should be taken to avoid overstaining when refinishing old floors, because of potential color change. Rotary cut veneers are reported to display such strong natural color that staining is sometimes unnecessary.
Varnishing is satisfactory. (See notes under staining).
The wood has poor painting qualities.
Response to Hand Tools
The wood, especially the latewood, is difficult to work with hand tools. Cutting edges should be kept sharp for best results.
The species has high bending strength in the air-dry condition. Strength in compression parallel to grain is also in the high range. Hardness is rated as medium, and weight is about average.
Douglas-fir is made up of two distinct geographic varieties: Coast and Rocky Mountain. Coast Douglas-fir, which is regarded as the typical Douglas-fir of the Pacific Coast, is described as a very large tree. Rocky Mountain Douglas-fir is medium-sized to large. Douglas-fir is reported to produce the most, in total volume, of timber, lumber, and plywood for veneer. Lumber from the base of old, large Douglas-fir trees is reported to be very valuable since the wood is clear and free from knots. Large Douglas-fir logs are reported to be conducive to process by rotary cutting into large sheets of veneer for making high strength, structural plywood.