Comparative Analysis of Wood Properties of Afzelia africana and Anogeissus leiocarpus Growing in Nigeria.

Abstract

Afzelia africana and Anogeissus leiocarpus are two timber species growing in Nigeria. The two species are used in the construction industry. While A. africana is regarded as a high grade wood species, A leiocarpus is referred to as a medium wood species. This study was carried out to determine the heartwood, sapwood and bark proportions of the two species along with their wood densities and alcohol benzene soluble extractable contents. The ages of the trees used in the study varied from 34 to 52 years in A. africana and 35 to 57 years in A leiocarpus. The heartwood ratio in A africana ranged from 44.6% to 75.9% with a mean of 60.9%.  The sapwood proportion also varied from 32.5% to 43.6% ,with a mean of 28.76%. The bark ratio varied from 5.8% to 12.24% with a mean of 10.20%.  The heartwood content of A. leiocarpus was a paltry 6.12% while the proportions of the sapwood and bark were 87.80% and 10.77% respectively. The mean densities of the two wood species were 716kg/m3 in A. africana and 731kg/m3in A. leiocarpus. The mean alcohol benzene soluble extractable content was 2.64% in A. africana and 1.82% in A. leiocarpus. The result obtained indicated that A. africana will be more durable and can be use without treatment in most applications while A. leiocapus may require adequate preservative treatment in situations where it will be used for outdoor purposes, most especially when it is to have contact with the ground in service.

Keywords: heartwood, sapwood, bark, density, extractives