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Darwin stringybark

Darwin stringybark's heartwood is pale reddish-brown with wide sapwood similar to forest red gum. Density (990-1200) kgm3 being hard, heavy and stiff, with exceptionally good impact properties comparable to the ironbarks.

Other Names

No other published names are in use

Botanical Name

Eucalyptus tetrodonta

Common Form
Sawn
a white ruler on a wood surface

Sapwood pale yellow or white, fairly wide and not always clearly demarcated from the reddish-brown or pale red heartwood.  Texture (referring to vessel size) medium.  Grain mainly straight.  The figure is not prominent, and growth rings occasionally tending to distinct. The species is widely distributed through northern Australia from Queensland to Western Australia north of latitude 16oS; trees grow from close to sea level up to 300m.  Best growth occurs on moderately deep, well drained sandy soils.  Represents one of the larger species in the Northern Territory which produces good milling timber.  The species is also recommended for tropical forestry.  

Suitability for pulp and paper and composites:

The basic density of the species is higher than what paper manufacturers generally desire, and CSIRO studies have indicated that pulp yields from natural stands are low. The high basic density also makes the species less desirable for composite wood products such as laminated veneer lumber and medium density fibreboard but quite suitable for solid-wood products.

Wood characteristics:

Timber is of high density similar to that of the ironbarks making it hard, heavy and stiff, with exceptionally good impact properties.  It is not easy to work with machine operations and it is difficult to cut with hand tools.  Material tends to ride on planer cutters; straighter grain usually produces good surfaces.  A 15o cutting angle is recommended for stock with interlocked grain.  Quartersawn boards dry fairly rapidly provided mild drying schedules are used.  The timber is fissile (easy to split), and glues fairly well.  Wearing and weathering properties are good.  Sapwood is lyctus susceptible, heartwood occasionally attacked by termites.  Sapwood is probably permeable, but the heartwood is extremely difficult to impregnate.  The wood is often used in hewn or as rounds.

REFERENCES:

1  W.G. Keating and E. Bolza. (1982) Characteristics, properties and uses of timbers. Vol. 1., South-east Asia, Northern Australia and the Pacific. Inkata Press

2  W.J. Smith, W.T. Kyneston, M.L. Cause and J. G. Grimmett (1991) Building timbers.  Technical Pamphlet No. 1, Queensland Forest Service, Department of Primary Industries 

3  B. Budgeon (1981)/ The shrinkage and density of some Australian and South-East Asian timbers.  Tech paper (2nd series) No. 38, Division of Building Research, CSIRO, Australia

4  E. Bolza and N.H. Kloot (1963) The mechanical properties of 174 Australian timbers.  Tech paper No. 25, Division of Building Research, CSIRO, Australia 

5  T. J. Venn (2003) Potential markets for logs and sawn timber from Darwin stringybark forests of Cape York Peninsula.  Marketing of farm-grown timber in tropical North Queensland : conference proceedings, 18 June 2003

FOOTNOTES:

SHRINKAGE - tangential and radial shrinkages after reconditioning, Values before reconditioning are slightly higher indicating low degree of wood collapse

DENSITY - Seasoned - after reconditioning

MOISTURE CONDITION - No specific data is available for seasoned material.  The seasoned values shown are estimated from corresponding green values from the Strength grouping classification as per (Ref 1)