Taun

Scientific name

Pometia spp. Principally P. pinnata, P. tomentose. Family: Sapindaceae.

Local names

Malugai (Philippines), kasai, sibu (Sarawak, Sabah), truong (Vietnam), aia fai, mala, ula, ako dawa (Solomon Islands), tava (Western Samoa), ahabu, matoa (Papua New Guinea), malugay, akwa.

Description and natural occurrence

Large hardwoods with an irregular bole up to 25 m. Sometimes fluted with buttresses varying from shallow to high plank type. Cross-section often elliptical and form poor, resulting in short log lengths. Centre log diameter up to 2 m.

Taun occurs in low-lying coastal and riverine areas from Sri Lanka through South-East Asia, Papua New Guinea to the Solomons and Samoa.

Wood appearance

Colour. Heartwood varies from pink-brown to red-brown, darkening with age. Sapwood is pale to pink buff and not always demarcated from heartwood.

Grain. Straight grained, occasionally interlocked. Texture moderately coarse.

Wood properties

Density. 700 kg/m3 at 12% moisture content; approximately 1.4 m3 of seasoned sawn timber per tonne.

Strength groups. S4 unseasoned, SD4 seasoned.

Stress grades. F7, F8, F11, F14 (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. S3 unseasoned; SD3 seasoned.

Shrinkage to 12% MC. Approximately 5.6% (tangential); 3.4% (radial).

Unit shrinkage. 0.27% (tangential); 0.21% (radial). These values apply to timber of Pometia pinnata reconditioned after seasoning.

Durability above-ground. Class 2 - life expectancy 15 to 40 years.

Durability in-ground. Class 3 - life expectancy 5 to 15 years.

Lyctine susceptibility. Untreated sapwood is susceptible to lyctid borer attack.

Termite resistance. Not resistant.

Preservation. Sapwood is moderately resistant to preservative impregnation.

Seasoning. Seasons fairly well although care required. Some collapse will occur. Response to reconditioning can be variable.

Hardness. Moderately hard (rated 3 on a 6 class scale) in relation to indentation and ease of working with hand tools.

Machining. Taun saws and turns easily with only a moderate blunting effect on cutting edges.

Fixing. No difficulty has been experienced with the use of standard fittings and fastenings. It is readily bored and holds nails and screws well.

Gluing. Can be satisfactorily bonded using standard procedures.

Finishing. Can be polished to a smooth, high finish. Takes paints and stains well.

Uses

Construction. As sawn timber in general house framing, cladding, fascia and bargeboards, internal flooring, plywood. Not recommended for use as external decking under Queensland conditions.

Decorative. Lining, panelling, joinery, cabinetwork, outdoor furniture, carving, turnery, veneers.

Suitable for steam bending.

Others. Boat building, handles, cooperage.

Identification features

General characteristics

Sapwood. Lighter coloured but not always distinct from heartwood.

Heartwood. Light red-brown to red-brown, darkens to red-brown with exposure.

Texture. Medium to coarse and uniform, grain interlocked.

Wood structure

Vessels. Medium to large, visible without lens. Solitary and radial groups generally two to three but occasionally three to eight. Many groups consist of a large pore with a tail-like appendage of four to eight small pores. Vessel lines prominent and darker than the background surface. Tyloses present but not plentiful.

Parenchyma. Apotracheal as concentric terminal bands and paratracheal as narrow borders to the pores.

Rays. Fine, visible only with a lens, they appear to be flecked with white due to the presence of crystals.

Other features

Burning splinter test. A match size splinter burns to an ash.

Frothing test. Positive, with profuse and persistent lather.

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 16 August 2010