The Tree
A large tree, 30m to 45m in height, with a clear bole some 12m to 18m long, and a diameter of 1.0 to 1.5m.

The Timber
The sapwood is narrow, and pale in colour, and the heartwood is light red to dark red, darkening to a uniform red-brown mahogany shade. Gum veins or pockets may be present, and in some logs there may be small, dark markings caused by the fungus Fistulina hepatica. These may enhance the decorative value of the timber. The grain is usually fairly straight, but may be wavy or interlocked, and the texture is medium coarse, but even. The wood weighs about 820 kg/m3 when dried.

Drying
With care, jarrah air dries and kiln dries very well, but there is some tendency to warping and to surface checking, warping of wide pieces, when it does occur, being generally unresponsive to reconditioning treatment. Partial air drying prior to kiln drying usually gives the best results.

Strength
By comparison with European oak, jarrah is some 10 to 20 per cent superior in all strength categories except in resistance to splitting, where it is not quite as resistant. It is also a much harder timber than oak.

Working Qualities
Difficult - Rather difficult to work with hand tools, and fairly hard to machine. It has a moderate dulling effect on cutting edges, and tends to pick up in planing, particularly on quarter-sawn surfaces, or when wavy or interlocked grain is present. A reduction of cutting angle to 150 is advisable when a smooth planed surface is required. The timber glues satisfactorily, and holds screws well, but it is rather hard to nail. It takes a high polish.