Acacia rhodoxylon. Family: Leguminosae
Brown spearwood; rosewood
- Small tree, grows to 10–15m high.
- Stem is 15–25cm diameter.
- Stem and branches are often fluted.
- Bark is dark and sheds in curly flakes.
- Found in coastal and subcoastal parts of Central Queensland from near Eidsvold, north to southeast of Mt Garnet.
- Heartwood is deep red-brown to dark brown.
- Sapwood is cream to white.
- Grain is straight.
- If present, interlocked or wavy grain gives a 'ring' feature to polished surfaces.
- Texture is very fine and even.
Engineering and construction
- Used extensively, in the past, for fence posts.
- Not generally available in sizes suitable for engineered uses, even though strong enough—more suited to uses listed below.
- Fancy turnery, walking sticks, 'ringed' timber especially prized.
- Resonating parts of xylophones.
- Fingerboards and chin rests for violins (a substitute for ebony).
- Straight-grained timber may be used for sporting goods.
- Future potential for use in 'small-volume, high-value' niche markets.
- Density: 1280kg/m3 at 12% moisture content; about 0.75m3 of seasoned sawn timber per tonne.
- Strength groups: (S1) unseasoned, (SD1) seasoned (brackets indicate provisional value).
- Stress grades: F14, F17, F22, F27 (unseasoned); F22, F27, F34 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded hardwood for structural purposes.
- Joint groups: JD1 seasoned.
- Shrinkage to 12% moisture content: not available.
- Unit shrinkage: not available.
- Durability above-ground: Class 1 (life expectancy more than 40 years).
- Durability in-ground: Class 1 (life expectancy more than 25 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 negligible using available commercial processes.
- Seasoning: dries slowly with little degrade.
- Hardness: very hard (rated 1 on a 6-class scale) to indent and work with hand tools.
- Machining: using appropriate tooling and feed speeds, spear wattle dresses and machines well, resulting in a fine polish.
- Fixing: moderately fissile, be careful using standard fittings and fastenings.
- Gluing: as with most high-density species, machine and prepare surface immediately before gluing.
- Finishing: readily accepts paint, stain and polish.
- Sapwood: cream, distinct from heartwood.
- Heartwood: deep red-brown to dark brown.
- Vessels: solitary; small, indistinct to the naked eye; moderately numerous (4–12 per mm2).
- Vessel lines: fine, indistinct.
- Parenchyma (soft tissue):indistinct under a lens.
- Rays: fine, barely visible with a lens.
- Burning splinter test: match-size splinter burns slowly with a small, steady flame; embers glow for a long time, leaving a charcoal tip.
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.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018