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Blackbutt

Scientific name

Eucalyptus pilularis. Family: Myrtaceae

Other names

Pink blackbutt

Description

  • Moderate to large tree.
  • Grows 40–60m high with 1–2m stem diameter.
  • Straight slender trunk with circular cross-section.
  • Bark on the lower part of the trunk is dark grey-brown, fibrous and fissured.
  • Typical smooth gum-type bark on branches and uppermost part of the trunk

Occurrence

  • Found in coastal regions from southern New South Wales to Maryborough, Queensland.

Appearance

Colour

  • Heartwood is pale brown with a faint tinge of pink when freshly cut.
  • Sapwood is usually slightly paler than heartwood, but sometimes indistinguishable from heartwood.

Grain

  • Uniform, moderately-coarse texture.

Uses

Engineering

  • Sawn or round timber in wharf and bridge construction.
  • Railway sleepers.
  • Cross-arms, poles, piles, mining timbers.
  • Not recommended for in-ground poles when constructing pole-frame houses.

Construction

  • Unseasoned, sawn timber in general house framing, fascia and barge boards.
  • Seasoned, dressed cladding, internal and external flooring, lining and joinery.
  • Fencing, landscaping and retaining walls.

Decorative

  • Quality furniture, outdoor furniture.
  • Turnery, parquetry.

Others

  • Boat building (keel and framing components, planking, decking).
  • Coach, vehicle and carriage building.
  • Agricultural machinery.
  • Structural plywood, hardboard.

Properties

  • Air dry density: 930kg/m3 at 12% moisture content; about 1.1m3 of seasoned sawn timber per tonne.
  • Plantation-grown timber: age 4 years—64% mature timber density; age 11–17 years—80 to 88% mature timber density.
  • Strength groups: S2 unseasoned, SD2 seasoned.
  • Stress grades: F11, F14, F17, F22 (unseasoned), F17, F22, F27, F34 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes.
  • Joint groups: J2 unseasoned; JD2 seasoned.
  • Shrinkage to 12% MC: 7.3% (tangential), 4.3% (radial).
  • Unit shrinkage: 0.37 % (tangential) 0.26 % (radial)—these values apply to timber reconditioned after seasoning.
  • Durability above-ground: Class 1 (life expectancy more than 40 years).
  • Durability in-ground: Class 2 (life expectancy 15–25 years).
  • Lyctine susceptibility: sapwood is not susceptible to lyctine borer attack.
  • Termite resistance: resistant.
  • Preservation: sapwood readily impregnates with preservative but penetration of heartwood is negligible using available commercial processes.
  • Seasoning: satisfactorily dries using conventional air and kiln seasoning methods; slight tendency to collapse in young wood (near pith).
  • Hardness: hard (rated 2 on a 6-class scale) to indent and work with hand tools.
  • Machining: machines well.
  • Fixing: no difficulty 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—if these contain high tannin and extractives, then painted surfaces exposed to the weather may stain.

Identification features

General characteristics

  • Sapwood: slightly paler than heartwood.
  • Heartwood: light brown with occasional pink colouring.
  • Texture: open and uniform; grain straight but occasionally slightly interlocked; sometimes appears and feels greasy, similar to but not as obvious as tallowwood (E. microcorys).

Wood structure

  • Growth rings: absent.
  • Vessels: medium to large, often arranged in oblique chains; vessel lines are prominent on dressed longitudinal surfaces; frequent tyloses.
  • Parenchyma (soft tissue): invisible without a lens.
  • Rays: fine.

Other features

  • Burning splinter test: match-size splinter burns to charcoal without ash.
  • Gum veins: may contain gum (kino) veins.

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 edn, 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.