Brown salwood

  • A lesser species, A. crassicarpa, is also known as brown salwood.

Scientific name

Acacia aulacocarpa, A. mangium, A. crassicarpa. Family: Leguminosae

Other names

black wattle; hickory wattle (both species); sally wattle (A. mangium)

Description

  • Medium-size hardwood with flanged buttresses.
  • Grows to 30m high and 1m diameter on favourable sites.
  • Bark is thin, brown, hard and fissured.

Occurrence

  • Northern New South Wales along the eastern coast of Queensland to Cape York.
  • Coastal areas of the Northern Territory.

Appearance

Colour

  • Heartwood varies from light brown to brown, often streaked with darker markings.
  • Sapwood creamy white to pale brown.

Grain

  • Variable grain, coarse texture but rather even.

Uses

Construction

  • Limited use, in the past, for general house framing, flooring, linings and mouldings, but rarely used now for these purposes.

Decorative

  • Plywood.
  • Furniture.
  • Shop and office fixtures.
  • Joinery.
  • Turning.
  • Walking sticks.

Others

  • Fishing rods.
  • Archery bows.
  • Tool handles (axes and hammers).
  • Boat building (light).

Properties

  • Density at 12% moisture content; and about 1.3m3 of seasoned sawn timber per tonne:
    • aulacocarpa 800kg/m3
    • mangium 690kg/m3
    • crassicarpa 675kg/m3.
  • Strength groups:
    • A. aulacocarpa (S4) unseasoned; (SD4) seasoned
    • A. mangium (S5) unseasoned; (SD5) seasoned
    • A. crassicarpa (S5) unseasoned; (SD5) seasoned.
  • Stress grades: visually stress-graded according to AS 2082—2000: Timber—Harwood—Visually stress-graded hardwood for structural purposes
    • aulacocarpa F7, F8, F11, F14 (unseasoned), F11, F14, F17, F22 (seasoned)
    • mangium F5, F7, F8, F11 (unseasoned), F8, F11, F14, F17 (seasoned)
    • crassicarpa F5, F7, F8, F11 (unseasoned), F8, F11, F14, F17 (seasoned).
  • Joint groups:
    • A. aulacocarpa JD2 seasoned
    • A. mangium JD3 seasoned
    • A. crassicarpa J2 unseasoned; JD3 seasoned.
  • Shrinkage to 12% MC: 4.2% (tangential), 1.4% (radial)—these values apply to A. aulacocarpa.
  • Unit shrinkage: 0.36% (tangential), 0.14% (radial)—these figures apply to timber of A. aulacocarpa reconditioned after seasoning.
  • Durability above-ground:
    • A. aulacocarpa Class 2 (life expectancy 15–40 years)
    • A. mangium Class 3 (life expectancy 7–15 years)
    • A. crassicarpa Class 3 (life expectancy 7–15 years).
  • Durability in-ground:
    • A. aulacocarpa Class 2 (life expectancy 15–25 years)
    • A. mangium Class 3 (life expectancy 5–15 years)
    • A. crassicarpa Class 3 (life expectancy 5–15 years).
  • Lyctine susceptibility: untreated sapwood susceptible to lyctine borer attack.
  • Termite resistance: not resistant.
  • Preservation: sapwood will impregnate with preservative.
  • Seasoning: satisfactorily dries using conventional air and kiln seasoning.
  • Hardness: moderately hard (rated 3 on a 6-class scale) to indent and working with hand tools.
  • Machining: relatively easy to work and machine; turns well to a smooth finish.
  • Fixing: no difficulties using standard fittings and fastenings.
  • Gluing: satisfactorily bonds using standard procedures.
  • Finishing: staining is normally not necessary—it polishes and paints well.

Identification features

General characteristics

  • Sapwood: creamy white, distinct from heartwood.
  • Heartwood: light brown to chestnut, occasionally with darker streaks.
  • Texture: medium to coarse; straight grain; lustrous.

Wood structure

  • Vessels: medium to large, visible without lens, solitary and radial chains of up to 3, uniform distribution; vessel size tends to decrease with the zone of latewood; vessel lines visible.
  • Parenchyma (soft tissue): indistinct.
  • Rays: very fine, barely visible with lens.

Other features

  • Burning splinter test: match-size splinter burns to charcoal.

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