Radial and axial variations in selected physical properties of Nauclea diderrichii wood grown in Yakurr, Cross River State, Nigeria

This study investigated the influence of radial and axial positions on variations in moisture content, density and swelling characteristics of Nauclea diderrichii wood using ASTM D 4442-84, ASTM D 2395 and ISO 13061-15 protocols, respectively. Five trees were sampled at 10%, 30%, 50%, 70% and 90% of merchantable height, with specimens obtained from the core, middle and outerwood regions. Density, oven-dry moisture content and swelling properties were determined. Data were analysed using two-way analysis of variance at the 0.05 probability level. Mean density ranged from 629.53 kg/m³ in corewood to 705.17 kg/m³ in outerwood. Density was significantly influenced by both radial and axial positions, while moisture content (10.14–11.17%) was not influenced. The coefficient of anisotropy ranged from 1.45 to 2.05, while 14-day volumetric swelling varied between 20.08% and 24.80%, indicating moderate dimensional stability. These findings highlight the need for position-based material selection to optimise wood performance in structural applications.