Acacia mollissima

syn. A. mearnsii

Black Wattle

Family: Leguminosae

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)

M 150 282-3Logs are delivered to a sawmill in southern Nigeria. African mahogany

(mostly Khaya ivorensis) is in high demand on overseas markets. Export of logs fro

this region, as well as from most other tropical areas, is being restricted.

M 150 282-2Band mills in Ghana are designed to handle logs 5 feet and more in

diameter. Obeche or Wawa (Triplochiton scleroxylon) logs yield lumber favored for

joinery and millwork.