Acacia mollissima syn. A. mearnsii
Family: Leguminosae
Black Wattle
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Other Common Names: None.

 

Distribution: Native to Australia but extensively planted in East and South Africa and elsewhere.

 

The Tree: A small tree 20 to 50 ft high.

 

The Wood:

General Characteristics: Heartwood pale brown with a pinkish tinge; not sharply demarcated from the sapwood.  Grain commonly interlocked; luster medium; texture moderately fine and uniform; without distinctive odor or taste.

 

Weight: Basic specific gravity (overdry weight/green volume) 0.60; air-dry density 45 pcf.

 

Mechanical Properties: (2-cm standard)

 

Moisture content   Bending strength   Modulus of elasticity   Maximum crushing strength

            (%)                  (Psi)                            (1,000 psi)                   (Psi)

Green (35)                   11,550                         1,620                           5,170

12%                             17,500                         2,080                           8,800

 

Janka side hardness 1,280 lb for green material and 1,750 lb at 12% moisture content.

 

Drying and Shrinkage: Dries rapidly but with pronounced warp, particularly cupping. Shakes tend to open and knots to split slightly.  Kiln schedule T2-D4 is suggested for 4/4 stock and T2-D3 for 8/4.  No data on shrinkage available but reported to have a large movement.

 

Working Properties: No data available on machining characteristics but tests in Australia indicate its suitability for cutting into veneer.

 

Durability: Heartwood nondurable; sapwood vulnerable to Lyctus beetle attack.

 

Preservation: Reported to be moderately resistant to preservative treatments.

 

Uses: Mining props, flooring parquet and strips, hardboard.  Mainly cultivated for the rich tannin content of the bark, reaching 40 to 50%.

 

Additional Reading: (17), (35)

 

17.  Farmer, R. H. (Editor).  1972.  Handbook of hardwoods.  H. M. Stationery Office, London.

35.  Lavers, G. M. 1967.  The strength properties of timbers.  For.  Prod.  Res. Bull.  No. 50. H. M. Stationery Office.  London.

 

From: Chudnoff, Martin. 1984. Tropical Timbers of the World. USDA Forest Service. Ag. Handbook No. 607.