Karri

Eucalyptus diversicolor

Karri is one of Australia's tallest hardwoods, with height from 45 to 70 m. It is native to south-west Western Australia on site-specific soils around Manjimup, about 300 km south of Perth. The mean annual rainfall in the area of occurrence is mainly from 900 mm to 1300 mm, and occurring in winter. Outlying forests, away from the main karri belt, occur between Karridale and Forest Grove, and other smaller ones are at Mount Many Peaks, Torbay, Rocky Gully and the Porongorup Range.

Wood description [more info]
Heartwood of timber from mature trees is pale pink to reddish brown, although regrowth heartwood is a lighter colour. The sapwood is white and usually easy to distinguish.

Wood density [more info]
Green density is about 1200 kg/m3, air-dry density about 900 kg/m3, and basic density about 690 kg/m3.

Shrinkage [more info]
Tangential and radial shrinkage before reconditioning are 10.0 and 4.5 per cent respectively, and after reconditioning 8.5 and 4.0 per cent respectively.

Workability [more info]
Karri is less easy to work than jarrah, even with sharp tools. When dressing the timber, the planer angle may need to be reduced to 15°. It generally requires additional sanding after moulding.

Durability [more info]
Durability Class based on the CSIRO 1996 ratings is 3/2 for decay and 4 for decay + termites. Sapwood is Lyctus-susceptible.

Strength group and properties [more info]
Green and dry strength groups are S3 and SD2. The more important strength properties are given in the table below.

Property	Units	Green	Dry
Modulus of Rupture	MPa	73	132
Modulus of Elasticity	MPa	14000	19000
Max Crushing Strength	MPa	36	72
Hardness	KN	6.0	9.0

Uses [more info]
Karri is now being used more extensively for flooring and panelling, and has potential for fine design furniture because of its high strength. It has been used extensively for general construction, shipbuilding, sleepers, guides or side beams in mines, structural plywood, roofing timbers and pulp and paper. Greater lengths are available than from any other Western Australian hardwood.

Availability [more info]
The species has been one of the major timber species of Western Australia and available both locally and interstate. Availability will be restricted considerably with most of the resource now in conservation reserves.