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Douglas-fir is one of the world's best timber-producing species and yields more timber than any other species in North America, making the forestlands of western Oregon, Washington, and British Columbia the most productive on the continent. In 2011, Douglas-fir represented 34.2% of US lumber exports, to a total of 1.053 billion board-feet.
By far the best-known is the very widespread and abundant North American species Pseudotsuga menziesii, a taxonomically complex species [14] divided into two major varieties (treated as distinct species or subspecies by some botanists): coast Douglas-fir or "green Douglas-fir", on the Pacific coast; and Rocky Mountain Douglas-fir or "interior ...
Coast Douglas-fir is the fourth tallest conifer and fifth tallest of all trees in the world (after sitka spruce).Currently, coast Douglas-fir trees 60–75 metres (197–246 ft) or more in height and 1.5–2 metres (4.9–6.6 ft) in diameter are common in old growth stands, [4] and maximum heights of 100–120 metres (330–390 ft) and diameters up to 4.5–5.5 metres (15–18 ft) have been ...
Pseudotsuga menziesii var. glauca, or Rocky Mountain Douglas-fir, is an evergreen conifer native to the interior mountainous regions of western North America, from central British Columbia and southwest Alberta in Canada southward through the United States to the far north of Mexico. [2]
Interior West Douglas Fir Pseudotsuga Menziesii: Green 460 26.7 53 Interior West Douglas Fir Pseudotsuga Menziesii: 12.00% 500 51.2 87 Interior North Douglas Fir Pseudotsuga menziesii var. glauca: Green 450 23.9 51 Interior North Douglas Fir Pseudotsuga menziesii var. glauca: 12.00% 480 47.6 90 Interior South Douglas Fir Pseudotsuga lindleyana ...
Specific modulus is a materials property consisting of the elastic modulus per mass density of a material. It is also known as the stiffness to weight ratio or specific stiffness.
It is particularly useful in regeneration of tree species such as Douglas-fir (Pseudotsuga menziesii) which is shade intolerant. [verification needed]. In addition, the general public's distaste for even-aged silviculture, particularly clearcutting, is likely to result in a greater role for uneven-aged management on public lands as well. [124]
When testing wood in lumber form, the Janka test is always carried out on wood from the tree trunk (known as the heartwood), and the standard sample (according to ASTM D143) is at 12% moisture content and clear of knots. [3] The hardness of wood varies with the direction of the wood grain. Testing on the surface of a plank, perpendicular to the ...