RESISTANCE OF NEEM (AZADIRACHTA INDICA A. JUSS)
WOOD TO CLEAVAGE: A QUANTITATIVE EXPERIMENTAL ANALYSIS

Michael AKPAN
Senior Lecturer, PhD. - Federal University of Technology, Yola, Dept. of Forestry and Wildlife Management
Address: P.M.B. 2076, Yola, Adamawa State, Nigeria
E-mail: michaelakpn@yahoo.com

Abstract:
This paper determines the resistance to cleavage of Neem (Azadirachta indica A. Juss) wood in relation to utilisation as structural timber. Three study locations were randomly selected from defined vegetation zones of North Eastern Nigeria for the study. These are Maiduguri, in Sahel savanna; Yola, in Sudan savanna; and Bauchi, in Guinea savanna. From each of the study locations, 15 matured tree samples of Neem were randomly selected, from which a total of 135 wood specimens were prepared for the resistance to cleavage experiment, using Romanian Standard methods of testing clear-wood specimens. The analysis of variance (ANOVA) statistics was used to analyze the obtained data, by testing for the level of significance of cleavage between the sampled trees, their sections, and the vegetation zones. Results showed that at mean moisture content of 18%, the Neem tree has average cleavage value of 1.46 N/mm2. The ANOVA showed highly significant differences between the trees and the vegetation zones at 1% level of probability (P<0.01).  However, only significant difference was obtained between the tree sections at 5% level of probability (P <0.05). Findings also revealed that cleavage of Neem wood compares favourably with those of local wood species used for structural timber in Nigeria. Thus, Neem wood possesses a high resistance to cleavage and could be suitable for structural timber utilisation.

Key words: cleavage, Neem wood, moisture content, structural timber, tree samples, tree sections, vegetation zones.