Yellow walnut
Scientific name
Beilschmiedia bancroftii. Family: Lauraceae
Other names
Canary ash; yellow nut
Description
- Well-shaped, medium-sized tree
- Grows 25–30m high.
- Stem is 1.0–1.5m diameter.
- Trunk is sometimes crooked or irregular and slightly buttressed for 2–5m from the ground line.
- Bark can be up to 25mm thick, brown and partly rough with small pustules.
- When cut, the middle layer of bark is reddish brown and has an odour like sugar cane.
Occurrence
- Occurs in North Queensland rainforests around the:
- Johnstone and Russell Rivers
- Evelyn and Daintree Rivers
- Bellenden-Kerr Range
- Atherton Tableland.
- Timber has very limited commercial availability.
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 (pattern).
Uses
- Decorative: plywood, furniture, joinery, turnery, carving, panelling.
- Other: sawn timber in general house framing, flooring, linings, mouldings and joinery.
Properties
- Density: 640kg/m3 at 12% moisture content; about 1.6m3 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 according to 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 0–7 years).
- Durability in-ground: Class 4 (life expectancy 0–5 years).
- Lyctine susceptibility: untreated sapwood susceptible to lyctid borer attack.
- Termite resistance: not resistant.
- Preservation: sapwood readily impregnates with preservative, but penetration of heartwood is unsatisfactory using available commercial processes.
- Seasoning: dries satisfactorily using conventional air and kiln seasoning.
- Hardness: firm (rated 4 on a 6-class scale) to indent and work with hand tools.
- Machining: abrasive to machine cutters and tools due to silica in the wood.
- Fixing: no difficulty using standard fittings and fastenings.
- Gluing: bonds satisfactorily using standard procedures.
- Finishing: readily accepts stain, polish and paint.
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 is generally straight.
Wood structure
- Growth rings: absent.
- Vessels: solitary or in radial groups of 2–5 cells with occasional clusters; medium and evenly distributed; obvious vessel lines on dressed longitudinal surfaces.
- Parenchyma (soft tissue): numerous, irregularly spaced, apotracheal bands—prominent as they are lighter 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 (pattern) due to earlywood/latewood cells forming rings.
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.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018