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Tasmanian oak

Scientific name

Eucalyptus regnans, E. delegatensis, E. obliqua. Family: Myrtaceae

Other names

Mountain ash; Victorian ash (E. regnans); alpine ash; woolybutt (E. delegatensis); messmate stingybark; brown-top stringybark (E. obliqua)


  • Large trees, grow to 90m.
  • Stem grows to 2.5m diameter at the base.
  • Trunks are free of branches to a great height.
  • Bark is rough and persistent (doesn’t shed) to the small branches on E. obliqua but only on the lower half of the trunk of the other species—above this it’s smooth.


  • E. regnans occurs abundantly in eastern Victoria and Tasmania.
  • E. delegatensis has a wide distribution in south eastern Australia, found at elevations of 600–900m in Tasmania and 900–1200m in Victoria.
  • E. obliqua has a wider distribution extending into parts of southern Queensland.



  • Heartwood is pale brown to white-brown and often with pinkish tints.
  • Generally sapwood and heartwood are the same colour.


  • Generally moderately open to coarse, but even and straight.
  • Growth rings are often noticeable.


  • Decorative: furniture, linings, parquetry flooring, laminated beams, joinery, turnery.
  • Other: sawn timber in general house framing, internal flooring, joinery.


  • Density: 675-770kg/m3 at 12% moisture content; 1.3 to 1.5m3 of seasoned sawn timber per tonne.
  • Strength groups: S4 unseasoned, SD4 seasoned.
  • Stress grades: F7, F8, F11, F14 (unseasoned); F11, F14, F17, F22 (seasoned) when visually stress-graded according to AS 2082—2000: Timber—Hardwood—Visually stress-graded for structural purposes.
  • Joint groups: J3 unseasoned, JD3 seasoned.
  • Shrinkage to 12% MC: E. regnans—13.3% (tangential), 6.6% (radial); E. delegatensis—8.5% (tangential), 5.2% (radial); E. oblique—11.3% (tangential), 5.1% (radial).
  • Unit shrinkage: E. regnans—0.36% (tangential), 0.23% (radial); E. delegatensis—0.35% (tangential), 0.22% (radial). E. oblique—0.36% (tangential), 0.23% (radial). These values apply to timber reconditioned after seasoning.
  • Durability above-ground: Class 3 (life expectancy 7–15 years).
  • Durability in-ground: Class 4 (life expectancy 0–5 years).
  • Lyctine susceptibility: untreated sapwood of E. delegatensis and E. obliqua is susceptible to lyctid borer attack; untreated sapwood of E. regnans is not susceptible; normally marketed as a mix of the 3 species; therefore, classed as lyctid susceptible.
  • Termite resistance: not resistant.
  • Preservation: sapwood readily impregnates with preservative, but penetration of heartwood is negligible using available commercial processes.
  • Seasoning: be careful when seasoning as prone to collapse and internal checking; also prone to surface checking on the tangential surfaces.
  • Hardness: firm to moderately hard (rated 3 and 4 on a 6-class scale) to indent and work with hand tools.
  • Machining: machines, and turns well, to a smooth surface.
  • Fixing: no difficulty using standard fittings and fastenings.
  • Gluing: bonds satisfactorily using standard procedures.
  • Finishing: readily accepts stain, polish and paint.

Identification features

General characteristics

  • Sapwood: similar to the heartwood.
  • Heartwood: pale brown to white-brown and often with pinkish tints.
  • Texture: open to moderately open; grain is usually straight; gum veins sometimes prominent in E. regnans.

Wood structure

  • Growth rings: may be prominent in E. regnans and E. delegatensis and occasionally in E. obliqua.
  • Vessels: single, medium to large in allspecies, often forming oblique chains in E. obliqua; may be more common in the early wood; tyloses vary from very few in E. regnans to common in E. obliqua; vessel lines are prominent on dressed longitudinal surfaces of all species.
  • Parenchyma (soft tissue): indistinguishable, even with a lens.
  • Rays: fine, not prominent.

Other features

  • Burning splinter test: all species burn to charcoal, sometimes with small amounts of grey or black ash.
  • Figure (pattern): generally lacking but occasionally wavy on quarter-sawn surfaces.

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.
  • 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.
  • 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 International, Strathfield, NSW.