Coronavirus (COVID-19) update: We are currently updating information following recent Queensland and Australian Government announcements. Find assistance and support for coronavirus affected businesses and industries.

Taun

Scientific name

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

Other 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

  • Large hardwood with irregular bole (trunk) up to 25m.
  • Sometimes fluted with buttresses varying from shallow to high-plank type.
  • Cross-section is often elliptical with poor form, causing short log lengths.
  • Centre log diameter up to 2m.

Occurrence

  • Occurs in low-lying coastal and riverine areas from Sri Lanka through Southeast Asia, Papua New Guinea to the Solomon Islands and Samoa.

Appearance

Colour

  • Heartwood is 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 is moderately coarse.

Uses

  • Construction: sawn timber in general house framing, cladding, fascia and bargeboards, internal flooring, plywood; not suitable for external decking under Queensland conditions.
  • Decorative: lining, panelling, joinery, cabinetwork, outdoor furniture, carving, turnery, veneers; suitable for steam bending.
  • Others: boat building, handles, cooperage.

Properties

  • Density: 700kg/m3 at 12% moisture content; about 1.4m3 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 according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes.
  • Joint groups: S3 unseasoned, SD3 seasoned.
  • Shrinkage to 12% MC: about 5.6% (tangential), 3.4% (radial).
  • Unit shrinkage: Pometia pinnata—0.27% (tangential), 0.21% (radial)—these values apply to timber reconditioned after seasoning.
  • Durability above-ground: Class 2 (life expectancy 15–40 years).
  • Durability in-ground: Class 3 (life expectancy 5–15 years).
  • Lyctine susceptibility: untreated sapwood is susceptible to lyctid borer attack.
  • Termite resistance: not resistant.
  • Preservation: sapwood is moderately resistant to impregnating with preservative.
  • Seasoning: seasons fairly well—be careful as some collapse will occur; response to reconditioning varies.
  • Hardness: moderately hard (rated 3 on a 6-class scale) to indent and work with hand tools.
  • Machining: saws and turns easily with only moderate blunting of cutting edges.
  • Fixing: no difficulty using standard fittings and fastenings; bores readily, and holds nails and screws well.
  • Gluing: satisfactorily bonds using standard procedures.
  • Finishing: polishes to a smooth, high finish; takes paints and stains well.

Identification features

General characteristics

  • Sapwood: lighter colour but not always distinct from heartwood.
  • Heartwood: shades of red-brown, darkens with exposure.
  • Texture: medium to coarse and uniform, grain is interlocked.

Wood structure

  • Vessels: medium to large, visible without lens; solitary and radial groups generally 2–3 but occasionally 3–8; many groups consist of a large pore with a tail-like appendage of 4–8 small pores; prominent vessel lines, darker than the background surface; some tyloses.
  • Parenchyma (soft tissue): apotracheal as concentric terminal bands, and paratracheal as narrow borders to the pores.
  • Rays: fine, visible only with a lens; appear flecked with white due to the presence of crystals.

Other features

  • Burning splinter test: match-size splinter burns to an ash.
  • Frothing test: positive, with profuse and persistent lather.

Research and resources

  • Boland, DJ, Brooker, MIH, Chippendale, GM, Hall, N, Hyland, BPM, Johnston, RD, Kleinig, DA and Turner, JD 2006, Forest trees of Australia, 5th ed., CSIRO Publishing, Collingwood, Australia.
  • Bootle, K 2005, Wood in Australia: types, Properties and uses, 2nd ed., McGraw-Hill, Sydney.
  • Ilic, J 1991, CSIRO atlas of hardwoods, Crawford House Press, Bathurst, Australia.
  • Queensland Government, DAF 2018, Construction timbers in Queensland: Properties and specifications for satisfactory performance of construction timbers in Queensland. Class 1 and Class 10 buildings, Books 1 & 2, Department of Agriculture and Fisheries, Brisbane.
  • Standards Australia, 2000, AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes, Standards Australia International, Strathfield, NSW.