Eucalyptus regnans, E. delegatensis, E. obliqua. Family: Myrtaceae
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.
- 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.
- 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.
- 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.
- Last reviewed: 12 Dec 2018
- Last updated: 12 Dec 2018