Variations pattern in selected mechanical properties of stem and branch woods of <i>Khaya grandifoliola</i> (Welw.) C. DC.

Abstract

This study was conducted to evaluate variations pattern in selected mechanical properties of stem and branch woods of Khaya grandifoliola with a view to identifying its utilization potentials. Wood samples were collected from Khaya grandifoliola in the Department of Forest Resources Management, University of Ibadan, Nigeria. Khaya grandifoliola tree was felled and sectioned into main boles, primary and secondary branch woods. Fifty centimetres (50cm) length bolts were obtained from the base, middle and top of the stem, two (2) primary branch woods and four (4) secondary branch woods. Bolts from the main bole were partitioned into innerwood, middlewood and outerwood sections of the radial and longitudinal positions at base 10, middle 50 and top 90% of the tree height. Planks were also obtained from the central portion of the bolts of primary and secondary branch and were further converted into test samples. Data obtained were analysed using descriptive statistics and ANOVA. The mean value of impact bending strength of stem wood was 1970.62 J/m². Primary and secondary branch woods had mean values of 1778 J/m² and 1812.93 J/m², respectively. The mean value of maximum compressive strength parallel to the grain of stem wood was 43.13 N/mm². Primary branch wood had mean value of 43.41N/mm², while the secondary branch wood had mean value of 44.31N/mm².The mean value of Modulus of Rupture of stem wood was 65.46 N/mm². Primary branch woods were 66.57N/mm while the secondary branch woods were 62.88 N/mm². The mean value of Modulus of Elasticity of stem wood was 11468.29 N/mm². Secondary and Primary branch woods had mean values of 13599.76N/mm² and 12069.82N/mm² respectively. The study revealed that wood from tree branches had similar characteristics with stem wood; and would perform same functions in wooden structures.

Keywords: Impact bending strength, maximum compressive strength, modulus of elasticity, modulus of rupture, utilization