The main purpose of this study is to provide the knowledge and data on the physical, mechanical and nanostructural properties of Acacia mangium wood from Sabah. A further objective was to examine the influence of microfibril angle (MFA) on strength, stiffness, tree age, the distance from pith to bark and the internal structure of the wood and to predict the perfect growth age which produces pure crystalline cellulose and more ordered. The results show that the fully grown which produce fully crystalline cellulose will denote as the optimum age (ao) was found to be 23.45 year for the pith...