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Bunya pine

Scientific name

Araucaria bidwillii. Family: Araucariaceae

Description

  • Tall softwood tree.
  • Grows 30–45m high and to 1.5m diameter.
  • Straight trunk, often branch-free for two-thirds of the height.
  • Distinctive crown which is symmetrical and domed, changing from a pointed to a flattened apex with age.
  • Not divided into branches, and leaves are clustered at the ends.
  • Bark is dark brown to black and persistent (doesn’t shed) with thin scales.
  • Leaves have either very short or no petioles, are lanceolate, sharply pointed, 2.0–5.0 by 0.5–1.0cm, hard and glossy green.
  • Cones and seeds are a lot larger than those of other Australian softwood species.
  • Seeds are edible.

Occurrence

  • Occurs mainly in south-eastern Queensland between Gympie and the Bunya Mountains northeast of Dalby.
  • Small, isolated occurrences on Mt. Lewis and at Cunnabullen Falls in northern Queensland.
  • Grows in moist valley floors as well as upper slopes and ridgetops in the ranges within about 160km of the coast.
  • Tops of trees, normally, emerge above the rainforest canopy, often associated with hoop pine.
  • Timber is not readily available, as trees are only removed for safety reasons or because they are in poor health.
  • Small plantings have been established next to hoop pine plantations, particularly in frost-free zones.

Appearance

Colour

  • Similar to hoop pine but slightly pink.
  • Heartwood is pale brown, sometimes with pink or cream streaks.
  • Sapwood is not clearly distinguishable.

Grain

  • Fine, even texture and a straight grain.
  • Faint growth rings.

Uses

  • General purpose softwood used in plywood, interior joinery, linings, mouldings, furniture and general, interior construction.
  • Musical instruments, especially sought after for guitar soundboards.

Properties

  • Density: 530kg/m3 at 12% moisture content; about 1.7m3 of seasoned sawn timber per tonne.
  • Strength groups: S6 unseasoned, SD5 seasoned.
  • Stress grades: F4, F5, F7, F8 (unseasoned); F7, F8, F11, F14, F17 (seasoned) when visually stress graded according to AS2858—2008: Timber—Softwood—Visually stress-graded softwoods for structural purposes.
  • Joint groups: J4 unseasoned, JD4 seasoned.
  • Shrinkage to 12% MC: 4% (tangential), 2% (radial).
  • Unit shrinkage: 0.23% (tangential); 0.11% (radial)–these values apply to timber reconditioned after seasoning.
  • Durability above-ground: Class 4 (life expectancy less than 7 years).
  • Durability in-ground: Class 4 (life expectancy less than 5 years).
  • Lyctine susceptibility: not susceptible.
  • Termite resistance: not resistant.
  • Preservation: heartwood is relatively easy to impregnate with preservatives.
  • Seasoning: dries rapidly but take precautions against bluestain.
  • Hardness: 1.7kN green, 2.3kN dry (Janka hardness).
  • Machining: easy to work.
  • Gluing: glues well.

Identification features

General characteristics

  • Sapwood: indistinguishable from heartwood.
  • Heartwood: pale yellow-brown to pink.
  • Texture: fine and even.

Wood structure

  • Rays: very fine and indistinct.

Other features

  • Burning splinter test: a splinter burns moderately well, with occasional faint crackling and a brownish exudation; embers die fairly quickly, leaving a thin, tawny brown ash.
  • Gum veins: absent.

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.