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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 15o.
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.
|
Property
|
Units
|
Green
|
Dry
|
|
Modulus
of Rupture
|
MPa
|
68
|
112
|
|
Modulus
of Elasticity
|
MPa
|
10000
|
13000
|
|
Max
Crushing Strength
|
MPa
|
36
|
61
|
|
Hardness
|
KN
|
5.7
|
8.5
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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.
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