Properties of Albizia schimperiana oliv.: a lesser-known agroforestry timber species from Moshi rural district, Kilimanjaro Tanzania

Abstract

Albizia schimperiana Oliv. is a lesser- known and lesser-utilized timber species found in the tropical eastern Africa. In Tanzania, particularly Kilimanjaro region this species is incorporated in agro-forestry systems as a shade tree for coffee. Using standard methods, this study investigated some potentials of A. schimperiana for timber. The studied properties are: i) Physical – Tree dimension, form and quality, wood colour, texture, workability and basic density ii) Strength - Static bending, compression, shear and cleavage. The average physical properties of A. schimperiana are as follows: The colour of sapwood is yellowish-white while that of heartwood is medium-brown and basic density is 455 kg m-3. The strength properties are: Modulus of elasticity (7,182 Nmm-2), Modulus of rapture (53.14 Nmm-2), Work to maximum load before failure (0.381 mmNmm-3), Compression parallel to the grain (35.5 Nmm- 2), Shear parallel to the grain (12.0 Nmm-2) and Cleavage (18.5 Nmm-2). The average strength properties are closely comparable to those of Bombax rhodognaphalon, Entandrophragma stolzii and Maesopsis eminii. With increasing scarcity of timber therefore, Albizia schimperiana can replace some uses of these traditional timber species. There is a strong relationship between basic density and strength properties except for Modulus of Elasticity. Albizia schimperiana should be promoted in agro-forestry and plantations to improve its timber availability and utilized in various uses as a substitute timber and also due to its high potential for
climate change mitigation.

Key words: Mfuruanje-density-Marangu- Maesopsis eminii- Bombax rhodognaphalon