Grey ironbark

Scientific name

Eucalyptus drepanophylla, E. paniculata. Family: Myrtaceae

Local names

White ironbark, narrow-leaved ironbark

Description and natural occurrence

A medium sized tree attaining a height of 30 to 50 m and a stem diameter of 1.5 m. The stem is usually straight and free of branches for a considerable length. The bark hard, coarse, deeply furrowed and ridged. It ranges from dark brown to black in colour and is persistent to the small branches.

E. drepanophylla is found from northern New South Wales to Bundaberg, Queensland. It is also found in scattered patches as far north as the Atherton Tableland.

E. paniculata - found only in New South Wales from Bega to Coffs Harbour.

Wood appearance

Colour. The heartwood ranges from reddish-brown to dark brown. The sapwood is lighter in colour and averages about 20 mm in width.

Grain. Tight and usually straight grained.

Wood properties

Density. 1105 kg/m3 at 12% moisture content; approximately 0.9 m3 of seasoned sawn timber per tonne.

Strength groups. S1 unseasoned; SD1 seasoned.

Stress grades. F14, F17, F22, F27 (unseasoned), F22, F27, F34, F34 (seasoned), when visually stress graded in accordance with AS 2082-1979, Visually stress-graded hardwood for structural purposes.

Joint groups. J1 unseasoned; JD1 seasoned.

Shrinkage to 12% MC. 7.5% (tangential); 4.7% (radial).

Unit shrinkage. 0.39% (tangential); 0.31% (radial). These values apply to timber of E. paniculata reconditioned after seasoning.

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

Durability in-ground. Class 1 - life expectancy over 25 years.

Lyctine susceptibility. Sapwood is not susceptible to lyctid borer attack.

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.

Machining. Not easily worked because of its high density; dressed surfaces have a steely sheen.

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 unseasoned timber in general house framing and as seasoned dressed timber in cladding, internal and external flooring, linings and joinery. Also in fencing, landscaping and retaining walls.

Decorative. Outdoor furniture, turnery, joinery.

Others. Boat building (keel and framing components, planking), coach, vehicle and carriage building, agricultural machinery, mallet heads, mauls, bearings, sporting goods (croquet mallets, parallel bars). Has been used for wheel spokes and bowling ninepins. Was reputedly the timber of choice for wooden-hulled vessels used in Antarctic exploration because its high strength and toughness gave the hulls high resistance to pack ice damage and crushing.

Identification features

General characteristics

Sapwood. Almost white, distinct from heartwood.

Heartwood. Varies from reddish-brown to dark brown.

Texture. Uniform, grain usually straight, sometimes interlocked.

Wood structure

Growth rings. Absent.

Vessels. Small to medium, solitary and diffuse, often containing tyloses.

Parenchyma. Sparse, not visible with a lens.

Rays. Fine, visible with a lens.

Other features

Burning splinter test. Produces a complete ash, grey to buff in colour.

Splinter shape. Fine needle like splinters produced when cutting across the grain are characteristic of this species and can be used to separate them from similar species.

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 04 August 2010