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Spotted gum is a species
that grows well on favourable sites, usually attaining 35-45 m in height
and 1-1.3 m diameter at breast height (dbh), with exceptionally
large trees reaching 70 m and exceeding 3 m dbh. On poorer sites it may
be 20-35 m in height and 0.7-1.2 m diameter. This species naturally occurs
in open-forest to tall open-forest formation on the east coast of Australia
from the Victoria-New South Wales border to the Maryborough District in
Queensland. Trial plantings have been established in the south-west of
Western Australia for pole timber.
Wood
description [more
info]
Heartwood is light brown to dark brown, and sapwood is pale
and up to 8 cm wide. The texture is moderately coarse, with an
interlocked grain, and the frequent presence of wavy grain produces an
attractive ' fiddleback' grain. The wood is slightly greasy and
gum veins are common.
Wood
density [more
info]
Green density is about 1150 kg/m3, the air-dry density about 970
kg/m3, and basic density about 790 kg/m3.
Shrinkage
[more
info]
Tangential and radial shrinkage before reconditioning are 6.1 and
4.3 per cent respectively, and after reconditioning 5.0 and 3.7 per cent
respectively.
Workability
[more
info]
The timber is not difficult to work. Unseasoned
wood is somewhat corrosive to aluminium nails and screws, and the high
extractives content can be a problem when gluing phenolic-type adhesives.
For good bonding a pressure of about 1000 kPa and temperatures above 200
C are usually needed. A low moisture content, preferably between
8 and 10 per cent, is also desirable.
Durability
[more
info]
Durability Class based on the 1996 CSIRO assessment
is 2 for decay, and 2 for decay + termites combined. Sapwood
is Lyctus-susceptible.
Strength
group and properties [more
info]
Green and dry strength groups are S2 and SD2 respectively. The more important
strength properties are given in the table below.
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Property
|
Units
|
Green
|
Dry
|
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Modulus
of Rupture
|
MPa
|
99
|
150
|
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Modulus
of Elasticity
|
MPa
|
18000
|
23000
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Max
Crushing Strength
|
MPa
|
50
|
75
|
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Hardness
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KN
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8.0
|
11.0
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Uses
[more
info]
The uses are as heavy
engineering construction and mining timbers, where shock resistance is
important, house framing, flooring, tool handles, piles and poles, shipbuilding,
agricultural machinery and plywood.
Availability
[more
info]
The timber is not readily available in Western Australia,
although common in New South Wales and southern Queensland.
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