|Scientific name||Dysoxylum mollisimum subsp. molle (formerly D. muelleri), D. cerebriforme. Family: Meliaceae|
Miva, red bean, onionwood (these names apply to D. mollisimum subsp. molle, only)
|Description and natural occurrence|
This rainforest tree grows to a height of 25-30 m and one metre in stem diameter. The trunk can be heavily flanged at the base but is not prominently buttressed. The bark is brown in colour with fine vertical fissures. It is shed in small chips. When freshly cut the bark and sapwood have a strong onion-like odour.
Miva mahogany is found in rainforests from the Clarence River, New South Wales, to the Daintree River, North Queensland.
Colour. The heartwood is red-brown in colour. Sapwood is creamy-pink and can be easily distinguished from heartwood.
Grain. Medium to coarse grained, uniform in texture; grain often interlocked. The soft tissue (parenchyma) gives a slight figure to the tangential surface.
Density. 625-640 kg/m3 at 12% moisture content; approximately 1.5 m3 of seasoned sawn timber per tonne.
Strength groups. (S5) unseasoned; (SD6) seasoned.
Stress grades. F5, F7, F8, F11 (unseasoned), F7, F8, F11, F14 (seasoned), when visually stress graded in accordance with AS 2082-2000, Timber - hardwood - visually stress-graded for structural purposes.
Joint groups. J3 unseasoned; JD3 seasoned.
Shrinkage to 12% MC. 4.3% (tangential); 2.7% (radial).
Unit shrinkage. 0.39% (tangential); 0.31% (radial). These values apply to D. muelleri only.
Durability above-ground. Class 3 - life expectancy 7 to 15 years.
Durability in-ground. Class 3 - life expectancy 5 to 15 years.
Lyctine susceptibility. Untreated sapwood is susceptible to lyctid borer attack.
Termite resistance. Not resistant.
Preservation. Sapwood readily accepts preservative impregnation but penetration of heartwood is negligible using currently available commercial processes.
Seasoning. Can be satisfactorily dried using conventional air and kiln seasoning methods.
Hardness. Firm (rated 4 on a 6 class scale) in relation to indentation and ease of working with hand tools.
Machining. Machines and turns well.
Fixing. No difficulty has been experienced with the use of standard fittings and fastenings.
Gluing. Can be satisfactorily bonded using standard procedures.
Finishing. Will readily accept paint, stain and polish.
Construction. Has been used as sawn timber in general house framing, flooring, linings, mouldings and joinery but is rarely found in these applications now.
Decorative. Furniture, plywood, shop and office fixtures, carving, turnery, joinery.
Others. Has been used for wine casks, brush stocks.
Sapwood. Creamy pink, distinctly lighter than heartwood.
Heartwood. Red-brown in colour.
Texture. Medium to coarse, grain often interlocked.
Vessels. Medium to large, visible without a lens, mostly in short radial rows of 2-4 cells but with some solitary. Lighter coloured vessel contents visible in many specimens. Vessel lines prominent on longitudinal surfaces.
Parenchyma. Abundant in fine, wavy, apotracheal bands of slightly lighter colour than the background.
Rays. Fine, not visible without a lens.
Burning splinter test. A match size splinter burns to charcoal. This distinguishes this species from the very similar, and closely related, rose mahogany, which burns to a white ash.
Figure. A pleasing but subdued figure, caused by the parenchyma bands, occurs on dressed tangential surfaces.
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 edn, McGraw-Hill, Sydney.
Hopewell, G (ed.) 2006, 'Construction timbers in Queensland: properties and specifications for satisfactory performance of construction timbers in Queensland, Class 1 and Class 10 buildings', books 1 and 2, Department of Primary Industries and Fisheries, Brisbane.
Ilic, J 1991, 'CSIRO atlas of hardwoods', Crawford House Press, Bathurst, Australia.
Standards Australia, 2000, 'AS 2082-2000: Timber - hardwood - visually stress-graded for structural purposes', Standards Australia.