Douglas fir from Canada and the USA may be graded and shipped for structural purposes in the species mix ‘Douglas fir- larch’ which comprises Douglas fir (Pseudotsuga menziesii) and western larch (Larix occidentalis). The mechanical properties quoted for material from Canada and USA are for this species mix.
A large tree attaining a height of 45m to 60m and a diameter of 1m to 2m, occasionally much taller and larger.
The heartwood is light reddish-brown in colour, usually quite distinct from the lighter coloured sapwood. The abrupt change and contrast in colour between early-wood and late-wood bands, produce a prominent growth ring figure which is a feature of plain-sawn surfaces and of rotary-cut veneer. The wood from trees grown in the UK appears to have less resin than the North American wood, and to some extent is of more rapid growth. The average weight of dried timber from either source is about 530 kg/m3.