Spotted gum

Corymbia maculata

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.

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.