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Warm, dense and resilient, Tasmanian Oak is the preferred hardwood for a wide range of applications.
It works extremely well and produces an excellent finish. It can be used in all forms of construction as scantlings, panelling and flooring, and can be glue-laminated to cover long spans. Veneers, plywood and engineered products are also available. It is also a popular furniture timber, and eucalypt fibre is sought after for reconstituted board and production of high-quality paper.
Tasmanian Oak is light in colour, varying from straw to reddish brown with intermediate shades of cream to pink. It is recognised for its excellent staining qualities, which allow ready matching with other timbers, finishes or furnishings.
The species grow in native forests. E. delegatensis is the dominant forest species in cooler, higher altitudes. E. obliqua is mainly found in lower altitudes, but ranges from the coast to 600m in hilly or mountainous country. E. regnans is widespread but it prefers well-drained soils in areas of high rainfall and low fire frequency.
Mature E. obliqua and mature E. delegatensis will survive even severe wildfires in contrast to the fire sensitive E. regnans, which does not survive even low-intensity fires. Seedlings of all three species establish best after fire has exposed bare mineral soils, with minimum leaf litter. They thrive when they are not overshadowed. The species are generally not successful as plantation stock as the seedlings do not respond well after transplanting.
These three species occur in Dry Eucalypt and Wet Eucalypt native forest types. 35% of these forest types is in reserve.
As the tallest flowering plant in the world, E. regnans grow up to 100m. E. delegatensis and E. obliqua do not reach these heights, reaching about 70m with the tallest trees achieving 90m.
The species produce buds in clusters of seven or more, with white cream flowers. The flowers are hermaphroditic.The leaves are asymmetrical and rounder in shape in their juvenile forms. E. regnans has green, asymmetrical lance-shaped leaves. E. obliqua has asymmetrical glossy green, leathery lance-shaped leaves while E. delegatensis has dull blue-green asymmetrical sickle-shaped leaves.
The bark of each of these species is characteristically ‘stringy’. E. obliqua’s bark is rough and persistent to the small branches. E. regnans’ rough bark sheds in long ribbons and is often seen hanging from the branches. E. delegatensis has reddish-brown to grey bark with longitudinal furrows on the lower trunk.
Tasmanian Oak Technical Details
- General Availability
- Tasmanian oak is readily available.
- Dressed seasoned timber 40 to 285 mm wide by 12 to 40 mm thick. Undressed seasoned timber 50 to 300 mm wide by 19 to 50 mm thick. Lengths up to 5400 mm long are available, with the bulk of production between 2700 and 4200 mm long.
- Grain is usually straight, open and even. It is occasionally coarse-grained or fiddle backed. Growth rings are visible and usually conspicuous.
- Uniform and smooth.
- Durability Description
- Termite resistance of heartwood: Not resistant. When used for exterior applications it should be painted or given a protective coating. Refer to AS 5604-2005 Timber - Natural durability ratings.
- In-ground: Class 4
- Above-ground: Class 3
- Movement - Shrinkage
- Approx. 5.5% radial, 11% tangential before reconditioning; 3.5% radial, 6.5% tangential after reconditioning.
- Unseasoned: Approx. 1000 kg/cu m
- Seasoned: Approx. 700 kg/cu m at 12% moisture content
- Strength Group
- Unseasoned: S3
- Seasoned: SD3
- Joint Group
- Unseasoned: J3
- Seasoned: JD3
- Structural Grades
- Most commonly available stress grades are F17 seasoned, F8 unseasoned.
- Toughness (Izod)
- Unseasoned: 13.0
- Seasoned: 18.0
- Hardness (Janka)
- Unseasoned: 4.2
- Seasoned: 5.7
Fire Hazard Properties
- Fire hazard Properties: Flooring (AS ISO 9239.1)
- Critial Radiant Heat Flux: Between 2.2 and 4.5 kW/m2
- Smoke Development Rate: Less than 750 %-min
- Fire Hazard Properties: Wall and Weiling Lining (AS/NZ 3837)
- Material Group: Not available
- Average Extinction Area: Less than 250 m2/kg
- Moderate. Can be severe in dense material.
- Cuts fairly cleanly with moderate feeding force.
- Moderate feeding forces required. Surfaces very smooth and lustrous when working "with" the grain.
- Surfaces are true and clean, even end grain. Holds edges well
- Easy to drill. Holes are usually clean and to size.
- Rebating + Mortising
- Generally produces excellent results.
- Pre-drilling is often necessary in seasoned or denser material. Nails hold well.
- Glues satisfactorily with most common adhesives.
- A good to fair bending timber. 25mm material bends reasonably well to radius of 100mm.
- Readily worked to a smooth, lustrous surface. Most finishes adhere very well. Stains very well.
Tasmanian Oak Environmental Details
- Native - Wet Eucalypt and Dry Eucalypt
- 35% of the total Tasmanian Oak forest types are reserved
- Chain of custody
- Carbon storage
- 308 kg/cu m
- R Values
- 0.57 (100mm)
- Tasmanian Oak is freely available and is continuously harvested.