Jarrah is found only on lateritic soils in south-west Western Australia, in the 650 to 1250 mm rainfall zone. Under optimum conditions it is a tall tree attaining 30 to 40 m in height with diameter at breast height up to 2 m. On poor sites the species is reduced to a mallee form.
Wood description [more info]
Heartwood of mature trees is dark-red, although regrowth is pinkish-red, while sapwood is pale yellow. The texture of the wood is relatively coarse but even, with the grain slightly interlocked and sometimes producing a fiddleback figure.
Wood density [more info]
Green density is about 1170 kg/m3, air-dry density about 820 kg/m3, and basic density about 670 kg/m3.
Shrinkage [more info]
Tangential and radial shrinkage before reconditioning are 7.5 and 5.0 per cent respectively, and after reconditioning 6.7 per cent and 4.6 per cent respectively.
Workability [more info]
The timber is relatively easy to work with sharp tools, although when dressing the planer angle may need to be reduced to 15°.
Durability [more info]
Durability Class based on the CSIRO 1996 ratings are 3/2 for decay, and 3/2 for decay + termites i.e. the wood is termite-resistant.
Strength group and properties [more info]
Green and dry strength groups are S4 and SD4 respectively. The most important strength properties are given in the table below.
|Modulus of Rupture||MPa||68||112|
|Modulus of Elasticity||MPa||10000||13000|
|Max Crushing Strength||MPa||36||61|
Uses [more info]
The major uses for jarrah are for joinery and furniture, panelling and flooring, although in the past the timber was used extensively for general construction, sleepers, poles and piles. In the 19th century it was widely used for cobbles.
Availability [more info]
Jarrah is the major timber species in Western Australia, and readily available locally and interstate.
Source : Forest Products Commission WA