Yellow walnut

Scientific name

Beilschmiedia bancroftii. Family: Lauraceae.

Local names

Canary ash, yellow nut

Distribution and natural occurrence

A well-shaped, medium-sized tree, attaining a height of 25 to 30 m and 1.0 to 1.5 m in stem diameter. The trunk is sometimes crooked or irregular and slightly buttressed for 2 to 5 m from the ground line. The bark can be up to 25 mm thick, brown in colour and somewhat rough with small pustules. When cut, the middle layer of bark is reddish-brown in colour and has an odour like sugar cane.

It occurs in North Queensland rainforests around the Johnstone and Russell Rivers, Evelyn and Daintree Rivers, Bellenden-Kerr Range and the Atherton Tableland.

Timber of this species is now of very limited commercial availability.

Wood appearance

Colour. Heartwood is pale to bright lemon yellow. Sapwood is generally paler but sometimes difficult to distinguish from the heartwood, especially since it can occupy up to 50% of the stem radius.

Grain. Moderately course, straight grained with little or no figure.

Wood properties

Density. 640 kg/m3 at 12% moisture content; approximately 1.6 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. J3 unseasoned; JD3 seasoned.

Shrinkage to 12% MC

3.8% (tangential); 2.1% (radial).

Unit shrinkage. 0.27% (tangential); 0.17% (radial). 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 but penetration of heartwood is unsatisfactory using currently available commercial processes.

Seasoning. Can be dried satisfactorily using conventional air and kiln seasoning methods.

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

Machining. Can be abrasive to machine cutters and tools due to the presence of silica in the wood.

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

Gluing. Can be bonded satisfactorily using standard procedures.

Finishing. Will readily accept stain, polish and paint.

Uses

Decorative. Plywood, furniture, joinery, turnery, carving, panelling.

Other. As sawn timber in general house framing, flooring, linings, mouldings and joinery.

Identification features

General characteristics

Sapwood. Pale yellow to nearly white.

Heartwood. Pale to bright lemon yellow, often with dark streaks towards the heart.

Texture. Moderately course and uniform, grain generally straight.

Wood structure

Growth rings. Absent.

Vessels. Solitary or in radial groups of 2 to 5 cells with occasional clusters. Medium in size and evenly distributed. Vessel lines conspicuous on dressed longitudinal surfaces.

Parenchyma. Numerous, irregularly spaced apotracheal bands, prominent due to being a lighter colour than the background.

Rays. Fine and distinct but less prominent than parenchyma.

Other features

Burning splinter test. Wood burns with some smoke to a charcoal tip and grey ash filament.

Figure. Dressed back-sawn surfaces may occasionally show figure due to a tendency for earlywood/latewood cell formation into rings.

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 25 August 2010