Blush walnut

Scientific name

Beilschmiedia obtusifolia. Family: Lauraceae.

Local names

Hard bollygum, tormenta

Description and natural occurrence

A large hardwood attaining a height of 50 m and a stem diameter of one metre. The trunk is sometimes flanged at the base. The bark is grey or brown, and scaly or marked by scattered indentations. Blush walnut occurs in coastal scrubs from the Clarence River area of New South Wales to the Cairns district.

Wood appearance

Colour. The heartwood is yellowish-brown to blush pink in hue, while the sapwood is paler.

Grain. Usually straight and fine grained.

Wood properties

Density. 770 kg/m3 at 12% moisture content; approximately 1.3 m3 of seasoned sawn timber per tonne.

Strength groups. S4 unseasoned; SD5 seasoned.

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

Joint groups. JD2 seasoned.

Shrinkage to 12% MC. 6.1% (tangential); 2.7% (radial).

Unit shrinkage. 0.36% (tangential); 0.19% (radial), respectively. These values apply to timber reconditioned after seasoning.

Durability above-ground. Class 4 - life expectancy 0 to 7 years.

Durability in-ground. Class 4 - life expectancy 0 to 5 years.

Lyctine susceptibility. Untreated sapwood susceptible to lyctid borer attack.

Termite resistance. Not resistant.

Preservation. Sapwood readily accepts preservative impregnation.

Seasoning. Careful drying is required to limit checking. Preliminary air drying under cover prior to kiln seasoning is recommended. Collapse is slight.

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

Machining. Hard to work because of its abrasive action on cutting edges.

Fixing. No difficulty has been experienced with the use of standard fittings and fastenings.

Gluing. Can be satisfactorily bonded using standard procedures.

Finishing. Will readily accept stain, polish and paint.

Uses

Decorative. Panelling, turnery, office fittings, scotia and cornice moulds, architraves, plywood.

Others. Internal flooring, framing, shelving, roof battens. Fishing rod butts, chisel handles, cases and crates, staves for tallow casks.

Identification features

General characteristics

Sapwood. Pale pink-brown.

Heartwood. Yellow-brown to pink-brown.

Texture. Medium to fine, grain straight.

Wood structure

Growth rings. Absent.

Vessels. Small, visible without lens; some solitary but most as short radial multiples. Vessel lines distinct on longitudinal surfaces.

Parenchyma. Abundant in irregularly spaced apotracheal bands, distinct without lens, also vasicentric visible under lens.

Rays. Distinct without a lens.

Other features

Burning splinter test. Match size splinter burns to a full white ash.

Oil cells. It is possible to detect these in cross-section, with the aid of a 10x lens.

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 28 July 2010