Coachwood

Scientific name

Ceratopetalum apetalum. Family: Cunoniaceae

Local names

Scented satinwood, tarwood

Description and natural occurrence

A medium-sized hardwood, straight-growing with smooth, fragrant, greyish bark. The stem has distinctive horizontal marks, or scars, which often encircle the trunk. Larger trees have short buttresses.

Occurs in the central and northern coastal rainforests of New South Wales and southern Queensland. The species prefers gullies and creeks and often occurs in almost pure stands.

Wood appearance

Colour. Heartwood pale pink, pinkish-brown. Sapwood not always distinguishable. The wood has a characteristic caramel odour.

Grain. Grain usually straight, texture fine and even, often highly figured on the tangential face due to numerous bands of soft tissue.

Wood properties

Density. 625 kg/m3 at 12% moisture content; approximately 1.6 m3 of seasoned, sawn timber per tonne.

Strength groups. S5 unseasoned; SD4 seasoned.

Stress grades. F5, F7, F8, F11 (unseasoned), F11, F14, F17, F22 (seasoned), when visually stress-graded in accordance with AS 2082-2000, Timber - hardwood - visually stress-graded for structural purposes.

Joint groups. J3 unseasoned; JD3 seasoned.

Shrinkage to 12% MC. 8.1% (tangential); 4.0% (radial).

Unit shrinkage. 0.34% (tangential); 0.24% (radial). These values apply to timber reconditioned after seasoning.

Durability above-ground. Class 4 - life expectancy less than 7 years.

Durability in-ground. Class 4 - life expectancy less than 5 years.

Lyctine susceptibility. Untreated sapwood susceptible to lyctine borer attack.

Termite resistance. Not resistant.

Preservation. Sapwood readily accepts preservative impregnation, but penetration of heartwood is negligible using currently available commercial processes.

Seasoning. Seasons well, but there is some risk of internal checking. Collapse slight and reconditioning not necessary.

Hardness. Firm (rated 4 on a 6 class scale) in relation to resistance to indentation and ease of working with hand tools.

Machining. Machines well to a smooth surface under hand or machine tools.

Fixing. Screws well, but tends to split in nailing therefore pre-drilling recommended.

Gluing. Glues well.

Finishing. Will readily accept paint and polish, however takes water and spirit stains better than oil stains.

Uses

Construction. Flooring.

Decorative. Furniture and cabinetwork, interior fittings, turnery, gun stocks, carving, veneer.

Others. Spars and masts in boat building.

Identification features

General characteristics

Sapwood. Pink brown.

Heartwood. Light-brown to pink-brown.

Texture. Fine and uniform, straight grained.

Wood structure

Vessels. Very small, visible only with lens; solitary, multiples and short radial chains.

Parenchyma. Plentiful in irregularly spaced apotracheal bands, distinct without lens.

Rays. Fine, visible with a lens.

Other features

Burning splinter test. A match size splinter burns to a partial white or grey ash.

Figure. Prominent on the back-sawn surfaces (tangential) due to bands of parenchyma.

Odour. Pronounced and characteristic, similar to caramel.

Further reading

Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, 'Forest trees of Australia', 5th edn, CSIRO Publishing, Collingwood Australia.

Bootle, K 2005, 'Wood in Australia: types, properties and uses', 2nd edn, McGraw-Hill, Sydney.

Hopewell, G (ed.) 2006, 'Construction timbers in Queensland: properties and specifications for satisfactory performance of construction timbers in Queensland, Class 1 and Class 10 buildings', books 1 and 2, Department of Primary Industries and Fisheries, Brisbane.

Ilic, J 1991, 'CSIRO atlas of hardwoods', Crawford House Press, Bathurst, Australia.

Standards Australia, 2000, 'AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes', Standards Australia.

Last updated 04 August 2010