Blackbutt

Scientific name

Eucalyptus pilularis. Family: Myrtaceae

Local name

Pink blackbutt

Description and natural occurrence

A moderate to large tree, attaining 40 to 60 m in height and 1 to 2 m in stem diameter. It has a straight slender trunk, circular in cross-section. The bark on the lower part of the trunk is dark grey-brown in colour, fibrous and fissured. Typical smooth gum type bark occurs on branches and the uppermost part of the trunk.

Found in coastal regions from southern New South Wales to Maryborough, Queensland.

Plantation-grown timber

The Department of Primary Industries and Fisheries is defining plantation site suitability for a number of hardwood timber species. Early results suggest that future supplies of plantation-grown blackbutt will be available from the Sunshine coast region (Gympie to Brisbane) and the Moreton region (the Lockyer, Brisbane and Logan Valleys) where mean annual rainfall exceeds 800 mm.

Wood appearance

Colour. The heartwood is pale brown with a faint tinge of pink when freshly cut. Sometimes the sapwood is indistinguishable from the heartwood but usually it is slightly paler in colour.

Grain. Moderately coarse textured and uniform.

Wood properties

Air dry density . 930 kg/m3 at 12% moisture content; approximately 1.1m3 of seasoned sawn timber per tonne.

Plantation-grown timber. Age 4 years: 64% mature timber density. Age 11-17 years: 80-88% mature timber density.

Strength groups. S2 unseasoned; SD2 seasoned.

Stress grades. F11, F14, F17, F22 (unseasoned), F17, F22, F27, F34 (seasoned), when visually stress graded in accordance with AS 2082:2000, Timber - Hardwood - Visually stress-graded for structural purposes.

Joint groups. J2 unseasoned; JD2 seasoned.

Shrinkage to 12% MC. 7.3% (tangential) 4.3% (radial)

Unit shrinkage. 0.37 % (tangential) 0.26 % (radial). These values apply to timber reconditioned after seasoning.

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

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

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

Termite resistance. Resistant.

Preservation. Sapwood readily accepts preservative impregnation but penetration of the heartwood is negligible using currently available commercial processes.

Seasoning. Can be satisfactorily dried using conventional air and kiln seasoning methods. Slight tendency to collapse in juvenile wood (near pith).

Hardness. Hard (rated 2 on a 6 class scale) in relation to indentation and ease of working with hand tools.

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. High tannin and extractives content can result in staining of painted surfaces exposed to the weather.

Uses

Engineering. As sawn or round timber in wharf and bridge construction, railway sleepers, cross-arms, poles, piles, mining timbers. Not recommended for poles in-ground in pole frame house construction.

Construction. As unseasoned, sawn timber in general house framing, fascia and barge boards and as seasoned dressed cladding, internal and external flooring, lining and joinery. Also in fencing, landscaping and retaining walls.

Decorative. Internal quality furniture, outdoor furniture, turnery, parquetry.

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

Identification features

General characteristics

Sapwood. Slightly paler than heartwood.

Heartwood. Light brown with occasional pink coloration in some samples.

Texture. Open and uniform. Grain straight but occasionally slightly interlocked. In some cases it has a greasy appearance and feel, similar to but not as pronounced as in tallowwood (E. microcorys).

Wood structure

Growth rings. Absent.

Vessels. Medium to large in size, often arranged in oblique chains. Vessel lines prominent on dressed longitudinal surfaces. Tyloses frequently present.

Parenchyma. Not visible without a lens.

Rays. Fine

Other features

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

Gum veins. Some pieces may contain gum (kino) veins.

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 28 July 2010