Grey ironbark
Scientific name
Eucalyptus drepanophylla, E. paniculata. Family: Myrtaceae
Other names
White ironbark; narrow-leaved ironbark
Description
- Medium-sized tree growing 30–50m.
- Stem grows to 1.5m diameter.
- Stem is usually straight and free of branches for a considerable length.
- Bark is hard, coarse, deeply furrowed and ridged.
- Bark ranges from dark brown to black and is persistent (doesn’t shed) to the small branches.
Occurrence
E. drepanophylla:
- Northern New South Wales to Bundaberg, Queensland
- Scattered patches as far north as the Atherton Tableland.
E. paniculata:
- New South Wales only from Bega to Coffs Harbour.
Appearance
Colour
- Heartwood ranges from reddish brown to dark brown.
- Sapwood is lighter in colour and averages about a 20mm wide band.
Grain
- Tight and usually straight grained.
Uses
Engineering
- Sawn and round timber used to construct wharf and bridges, railway sleepers, cross arms, poles, piles, mining timbers.
Construction
- Unseasoned timber in general house framing.
- Seasoned dressed timber in cladding, internal and external flooring, linings and joinery.
- 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).
- Past use for wheel spokes and bowling ninepins. Reputedly, the timber of choice for wooden-hulled vessels used in Antarctic exploration due to the timber’s high strength and toughness providing high resistance to pack ice damage and crushing.
Properties
- Density: 1105 kg/m3 at 12% moisture content; about 0.9m3 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 according to AS 2082—2000: Timber—Hardwood—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 more than 40 years).
- Durability in-ground: Class 1 (life expectancy more than 25 years).
- Lyctine susceptibility: sapwood is not susceptible to lyctid borer attack.
- Termite resistance: resistant.
- Preservation: sapwood readily impregnates with preservative, unlike the heartwood, where penetration is negligible using available commercial processes.
- Seasoning: satisfactorily dries using conventional air and kiln seasoning.
- Hardness: very hard (rated 1 on a 6-class scale) to indent and work with hand tools.
- Machining: not easily worked because of its high density; dressed surfaces have a steely sheen.
- Fixing: no difficulty using standard fittings and fastenings.
- Gluing: as with most high-density species, machine and prepare surface immediately before gluing.
- Finishing: readily accepts paint, stain and polish.
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 (soft tissue): sparse, not visible with a lens.
- Rays: fine, visible with a lens.
Other features
- Burning splinter test: produces a complete ash, grey to buff.
- Splinter shape: fine needle-like splinters are produced when cutting across the grain—characteristic of this species and can be used to separate them from similar species.
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.