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.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018