Androstachys johnsonii
Family: Androstachydaceae
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Mecrusse

 

Other Common Names: Lebombo ironwood, Nsimbitsi (Transvaal-South Africa), Cimbirre (Mozambique).

 

Distribution: Found in Southeast Africa, in mountainous areas along streams, frequently in pure stands.

 

The Tree: Reaches a height of 100 ft with a straight cylindrical bole to 50 ft; trunk diameters 2 to 3 ft.

 

The Wood:

General Characteristics: Heartwood light or medium brown, reddish tint, with darker markings; sapwood yellowish white, not sharply demarcated.  Texture very fine and even; grain straight to irregular and wavy; somewhat lustrous; without characteristic odor or taste.

 

Weight: Basic specific gravity (ovendry weight/green volume) 0.72; air-dry density  55 pcf.

 

Mechanical Properties: (2-cm standard)

 

Moisture content   Bending strength   Modulus of elasticity   Maximum crushing strength

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

12% (43)                     18,700             NA                  9,500

 

Janka side hardness 2,540 lb for dry material.

 

Drying and Shrinkage: Seasons slowly, prone to surface checking, requires careful air-drying using thin stickers and pile covers.  A kiln schedule similar to T3-D2 has been suggested.  Shrinkage green to ovendry: radial 5.8%; tangential 6.2%; volumetric 11.6%.

 

Working Properties: Reported to saw and machine without particular difficulty; a good turnery wood; gives a good finish; glues well.

 

Durability: Heartwood highly resistant to attack by decay fungi and termites.

 

Preservation: Very difficult to treat.

 

Uses: Flooring (parquet), heavy construction, railroad crossties, turnery, mine props.

 

 

 

Additional Reading: (3), (23), (43)

 

3. Bolza, E., and W. G. Keating.  1972.  African timbers-the properties, uses, and characteristics of 700 species.  CSIRO.  Div.  of Build.  Res., Melbourne,             Australia.

23.  France: Bois For.  Trop.  1965.  Androstachys johnsonii.  Bois For.  Trop.  103:60.

43.Portugal: Laboratoria Nacional de Engenharia Civil.  1965.  Ficha de  caracteristicas. Mecrusse.  Androstachys johnsonii. Lab. Nac. Eng. Civil., Lisbon No.  5.

 

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