Isoberlinia scheffleri

Mbarika

Family: Leguminosae

Other Common Names: None.

Distribution: Common in the rain forests of the East Usambara mountains in Tanzania.

The Tree: May reach a height of 160 ft with a bole length of 60 ft, buttressed to 12 ft; trunk diameters 4 to 5 ft. Stems often galleried by the larvae of a Prosopocera borer.

The Wood:

General Characteristics: Heartwood reddish brown with irregular darker and lighter bands; sapwood 3 to 4 in. wide, whitish, well differentiated. Texture coarse; grain straight or slightly wavy; green timber has an unpleasant odor; veins exude a grayish gum on freshly cut cross sections.

Weight: Basic specific gravity (ovendry weight/green volume) 0.65; air-dry density 50 pcf.

Mechanical Properties: (2-in. standard)

Moisture content Bending strength Modulus of elasticity Maximum crushing strength

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

12% (5) 14,900 2,120 8,180

Janka side hardness 1,420 lb at 12% moisture content.

Drying and Shrinkage: Seasons rather slowly with negligible checking but there is moderate degrade due to bow and spring. Kiln schedule T6-D2 is suggested for 4/4 stock and T3-D1 for 8/4. Shrinkage green to air-dry: radial 2.5%; tangential 5.9%. Movement in service is rated as medium.

Working Properties: Saws and machines well and dresses to a smooth finish. Machined timber tends to distort during storage due to residual stresses after drying.

Durability: Heartwood is nondurable and not resistant to termite attack.

Preservation: Heartwood is rated as resistant to preservative treatments; sapwood is moderately resistant.

Uses: Heavy construction, flooring.

Additional Reading: (3), (5), (55)