Oregon
Botanical name
Pseudotsuga menziesii
Pseudotsuga taxifolia
Origin
Oregon grows in North America and is grown in plantations in New Zealand and to a limited extent in Australia.
Trading names
Oregon
Douglas Fir
Appearance
Heartwoodyellow-brown to pale reddish brown.
Sapwooddistinctly paler.
Texturecoarse and uneven.
Graingenerally straight.
Growth ringsvery prominent.
Odourdistinctive on freshly cut surface.
General comment
Relatively easy to dry but the tangential surface is prone to surface checking.

End splitting is likely if drying is too rapid.

Moderately easy to work.

Care is needed in dressing because the softer earlywood may be compressed and later, on recovery, produce a ridged surface. This characteristic makes it unsuitable for steam bending.

Not a good base for paint because of the uneven nature of the wood and, in external applications, early failure is sometimes experienced on the latewood of tangential-cut material.

Inclined to split when nailed near ends of piece.

Differential glue absorption can occur.

Regrowth wood varies considerably in density and strength and it may be necessary to consider the percentage of latewood and the spacing of the growth rings in assessing quality.

Resin content can be high, causing occasional bleed-through of paint films.
Common uses
Internal framing, joinery, vats, boat building, plywood.
Properties
(See notes below)
Density
Average Green Density (GD): Nth American 700kg/m3 NZ(plantation) 800kg/m3
Average Air Dry Density (ADD): Nth American 550kg/m3 NZ(plantation) 420kg/m3
(source AS 1720.2)

Hardness rating
Average Hardness Rating - Dry: Soft

Lyctid Susceptibility of Sapwood
Not susceptible
(source AS 5604)

Termite Resistance of Heartwood (inside above ground)
Not resistant
(source AS 5604)

Marine Borer Resistance of Heartwood
Class 4
(source AS 5604)

Natural Durability Rating of Heartwood Above Ground
Class 4
(source AS 5604)

Natural Durability Rating of Heartwood In-Ground Contact
Class 4
(source AS 5604)


Notes
Density: 'Green Density' (GD) is the density of the wood at the time the living tree is felled. It varies considerably with the season, weather conditions, the age of the tree and so on; the quoted figure must therefore be accepted as a guideline only and when accurate green density figures are required for, say, assessment of transport costs, it is advisable to carry out accurate determinations on the materials involved.

'Dry Density' or 'Air Dry Density' (ADD) is the average density of the wood at 12 per cent moisture content. It too varies with conditions of growth, climate and maturity of wood.

There are published figures for both Green Density and Air Dry Density of most commercial species.

The figures given above have been rounded to the nearest 50.

Hardness rating: the hardness rating of a timber species is measured by the Janka Test. This is a standard test which measures the penetration into the timber of a common load and projectile. The results relate to a hardness capacity of the material and are expressed in kN. This information is useful where the timber may be subject to potential damage from impacts e.g. a dance floor. There are 2 sets of published figures; one for 'Green' or freshly felled timber and one for seasoned timber - i.e. timber with a moisture content of 12%.

The ratings given here are:
  Soft - less than 5.5
  Moderate - 5.5 to 7.0
  Hard - 7.1 to 10.0
  Very Hard - greater than 10.0.

Lyctid susceptible sapwood: Only the sapwood of some hardwoods is susceptible to lyctid borer attack. No softwoods are susceptible to attack.

Natural durability ratings: The natural durability rating of a timber species is a rating of the timber's resistance to attack by wood destroying fungi and wood destroying insects. The sapwood of all timber species has poor resistance and so the natural durability rating applies only to the heartwood of a timber species. The rating is based on the testing of stakes and poles embedded in the ground and on expert opinion of historical performance. There are 2 sets of ratings: one for above ground use and one for in-ground contact use. The lower the number the higher the performance in terms of durability. This information is useful for specifying material for external or exposed applications.
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