Variations in the physical and mechanical properties of balanites aegyptiaca wood from three provenances

Abstract

Balanites aegyptiaca is a characteristic and emblematic tree species native to the dry zones of Africa and Asia. It has considerable socio-economic importance throughout its natural range of distribution because of its multiple uses. Despite this, the technological properties of its wood are not well known, hence sometimes inappropriate uses but potential for others. In order to match applications to characteristics of the wood, we determined physical stability indicators (density, infradensity, total radial shrinkage, total tangential shrinkage, total volumetric shrinkage and fibre saturation point) and mechanical behaviour indicators (longitudinal modulus of elasticity, bending strength and compression strength). Ninety-three specimens taken from 13 trees from the Sahelian and Sudanian zones in Chad and the Sahelian zone in Senegal were tested. Our results show that B. aegyptiaca wood from these three provenances is medium-heavy (797 kg/ m3) with moderate dimensional stability: shrinkage anisotropy is above 2 (2.2) and total radial and tangential shrinkage rates are medium at 4 % and 8.5 % respectively. Its mechanical characteristics are medium (static bending and compression strength at 49.4 MPa and 104.5 MPa respectively) to weak (longitudinal modulus of elasticity at 10,473 MPa). A comparison of the results obtained according to the provenance of the specimens showed variable tendencies depending on the characteristics analysed, although the variations between the three provenances are limited. Our study results show that the use of B. aegyptiaca wood as a material could be appropriate for a wider range of purposes, on condition that suitable management methods are in place with a view to their restoration by planting.