Red mahogany

Scientific name

Eucalyptus resinifera, E. pellita. Family: Myrtaceae

Local names

Red stringybark, red messmate (E. resinifera), red stringybark, Daintree stringybark, large-fruited red mahogany (E. pellita).

Description and natural occurrence

A medium-sized tree attaining a height of 40-45 m and 1-1.5 m in stem diameter. The bark is rough and persistent to the small branches, fibrous, shallow to coarsely fissured. It is coloured greyish to reddish-brown (E. resinifera) and reddish-brown to brown (E. pellita).

E. resinifera occurs from Jervis Bay in New South Wales to Coen in Queensland.

E. pellita occurs from just north of Townsville to Iron Range on Cape York Peninsula and scattered areas from Gladstone in Queensland to southern coastal New South Wales.

Plantation-grown timber

Early research trials suggest that future supplies of plantation-grown E. pellita will be available from northern Queensland on suitable soils and where the mean annual rainfall exceeds 900 mm.

Wood appearance

Colour. The heartwood ranges from red to dark red. Sapwood is distinctively paler.

Grain. Generally medium textured with even grain. At times the grain can be interlocked, producing an attractive figure.

Wood properties

Air dry density. 995 kg/m3 at 12% moisture content; approximately 1.0 m3 of seasoned sawn timber per tonne.

* The density of 8.5-year-old plantation-grown timber is 70% that of mature, natural grown timber.

Strength groups. E. resinifera S2 unseasoned; SD3 seasoned. E. pellita (S2) unseasoned; (SD3) seasoned.

Stress grades. F11, F14, F17, F22 (unseasoned), F14, F17, F22, F27 (seasoned), when visually stress graded in accordance with AS 2082:2000, Timber - Hardwood - Visually stress-graded for structural purposes.

Joint groups. J1 unseasoned; JD1 seasoned.

Shrinkage to 12% MC. 6.3% (tangential); 3.9%(radial). These values are for E. resinifera only.

* 8.5-year-old plantation-grown E. pellita; 5.2% (tangential); 1.9% (radial).

Unit shrinkage. 0.34% (tangential); 0.27% (radial). E. resinifera reconditioned after seasoning.

* 8.5-year-old plantation-grown E. pellita. 0.28% (tangential); 0.17% (radial).

Durability above-ground. Class 1 - life expectancy > 40 years.

Durability in-ground. Class 2 - life expectancy 15 to 25 years.

Lyctine susceptibility. Untreated sapwood susceptible to lyctid borer attack. Timber should be sapwood free or chemically treated before sale in Queensland.

Termite resistance. 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. Very hard (rated 1 on a 6 class scale) in relation to indentation and ease of working with hand tools. 12 kN (mature native).

* 4.9 kN (8.5-year-old plantation timber).

Machining. Machines well.

Fixing. No difficulty has been experienced with the use of standard fittings and fastenings.

Gluing. As with most high density species, machining and surface preparation should be done immediately before gluing.

Finishing. Will readily accept paint, stain and polish.

Uses

Engineering. As sawn and round timber in wharf and bridge construction, railway sleepers, cross arms, poles, piles, mining timbers.

Construction. As sawn timber in general house framing, cladding, internal and external flooring, linings, joinery, fencing, landscaping, retaining walls.

Decorative. Internal quality furniture, outdoor furniture, turnery.

Others. Boat building (keel and framing components, planking), coach, vehicle and carriage building, agricultural machinery, structural plywood.

Identification features

General characteristics

Sapwood. Paler and distinct from heartwood.

Heartwood. Generally deep red in colour but may be lighter in younger material.

Texture. Uniform, coarse grain, often interlocked. An occasional tight gum vein.

Wood structure

Growth rings. Generally absent, but some specimens may tend to show vessels arranged in zones.

Vessels. Medium size, solitary, distributed in a diffuse pattern. Vessel lines conspicuous on longitudinal surfaces. Contains frequent tyloses and dark-red gum deposits.

Parenchyma. Variable in amount, not abundant; diffuse and paratracheal.

Rays. Fine, visible only with a lens.

Other features

Burning splinter test. A match size splinter burns to charcoal without ash.

Further reading

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.

Last updated 06 August 2010