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White mahogany

Scientific name

Eucalyptus acmenoides, E. umbra ssp. umbra, E. carnea, E. tenuipes. Family: Myrtaceae

Other names

Yellow stringybark; white stringybark

Description

  • E. acmenoides is a tall tree growing to 60m high and a stem more than 1m diameter.
  • E. umbra ssp. umbra and carnea are small to medium trees of 8–25m high and up to 1m stem diameter.
  • Bark is greyish-brown, rough, fibrous and persistent (doesn’t shed) over the whole trunk and branches, and tends to be stringy.

Occurrence

  • E. acmenoides is common in coastal areas from Sydney, New South Wales, to Rockhampton, Queensland, and isolated areas north to the Atherton Tableland.
  • E. umbra ssp. umbra occurs from Sydney, New South Wales, to Cooktown in Queensland but not between Rockhampton and Townsville.
  • E. umbra ssp. carnea occurs from Wyong, New South Wales to Bundaberg in Queensland.
  • Sawn timber is readily available.

Appearance

Colour

  • Heartwood is yellow-brown, closely resembling tallowwood.
  • Sapwood is usually paler and less than 20mm wide.

Grain

  • Generally medium texture and uniform, may be interlocked.
  • Greasy to feel, but not as pronounced as in tallowwood and spotted gum.

Uses

  • Engineering: sawn and round timber used to construct wharves and bridges, railway sleepers, cross arms, poles, piles, mining timbers.
  • Construction: sawn timber in general house framing, cladding, internal and external flooring, linings, joinery, fencing, landscaping, retaining walls.
  • Decorative: outdoor furniture, turnery, joinery.
  • Others: structural plywood, boat building (keel and framing components, planking), coach, vehicle and carriage building, agricultural machinery.

Properties

  • Density: 1010kg/m3 at 12% moisture content; about 1.0m3 of seasoned sawn timber per tonne.
  • Strength groups: Eucalyptus acmenoides—S2 unseasoned, SD3 seasoned, E. umbra ssp. umbra, E. carnea, E. tenuipes—(S2) unseasoned; (SD3) seasoned (brackets indicate provisional value).
  • Stress grades: F11, F14, F17, F22, (unseasoned); F14, F17, F22, F27(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: E. acmenoides—6.0% (tangential), 3.5% (radial); E. umbra ssp. carnea—5.4% (tangential), 2.8% (radial).
  • Unit shrinkage: not available.
  • Durability above-ground: Class 1 (life expectancy more than 40 years).
  • Durability in-ground: Class 1 (life expectancy more than 25 years).
  • Lyctine susceptibility: Eucalyptus acmenoides, E. umbra ssp. umbra, E. carnea—sapwood not susceptible to lyctid borer attack; E. tenuipes—susceptible.
  • Termite resistance: resistant.
  • Preservation: sapwood readily impregnates with preservative, but penetration of heartwood 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: machines, and turns well, due to its greasy nature.
  • 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

  • Sapwood: creamy brown and distinctly lighter than heartwood.
  • Heartwood: light brown to yellow-brown.
  • Texture: medium texture and uniform; grain is interlocked; greasy to feel, but not as pronounced as in tallowwood and spotted gum.

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.