Douglas Fir

Douglas fir: Pseudotsuga menziesii

We supply English Douglas fir, Welsh Douglas fir, Scottish Douglas fir and European Douglas fir.

Distribution

Douglas fir natural range is the Western USA and Canada. It is grown for timber throughout the UK, New Zealand and Australia.

Description

Douglas fir heartwood is light reddish brown, there is a stark contrast between the early and late stage growth shown in distinct growth rings. The timber is straight grained, sometimes there is a slight wave or spiral. Average weight 530 kg/m3; specific gravity .53.

Properties

Where the timber is grown effects the timbers mechanical properties. Wood from the Pacific coastal areas is heavier, harder and stronger than the wood from mountainous areas. Timber from the UK is the equivalent of timber from mountainous areas. Douglas fir has high stiffness and crushing strength, and high bending strength, with medium resistance to shock loads.

Seasoning

Douglas fir will dry quickly with little checking or warping. There is small movement in service. It should be noted that resin canals tend to bleed and show as narrow brown lines on longitudinal surfaces.

Working

Douglas fir works well with both hand and machine tools. Hard, loose knots may cause problems whilst cutting. It is recommended that pre-bores are used with nails, but the wood works well with crews and glue. The wood should be well prepared before staining or varnishing. Any timber with high resin content is best kiln dried before working.

Durability

The timber is subject to attack by the pinhole borer, longhorn beetle and jewel beetle, but is still moderately durable. Most Douglas fir is highly resistant to preservative treatments, this is especially true of the American mountain grown timber.

Uses

More plywood and veneer are produced from Douglas fir than any other wood. Also used in heavy construction and interior and exterior joinery.