The linear relationship between fibre morphological characteristics of entandrophragma cylindricum and the strength of its mortise-tenon joint

Abstract

Fibre properties influence wood strength. However, information on the fibre morphological characteristics, which have the greatest effect on wooden furniture joint strength, is scanty. The relationship [using the Pearson Product-Moment Correlation Coefficient (r)] between the fibre characteristics of the sapwood and heartwood of Entandrophragma cylindricum and the strength of their mortise-tenon joints was studied in order to guide furniture manufacturers on the selection of timber for strong joints. For both the heartwood and sapwood of E. cylindricum, fibre diameter had the greatest positive influence on joint strength [i.e., r = 0.996 (heartwood); 0.994 (sapwood)] followed by fibre double wall thickness (r = 0.990 and 0.993 respectively) and fibre length (r = 0.968 and 0.992 respectively). Fibre lumen diameter negatively correlated with joint strength [r = -0.987 (heartwood); -0.978 (sapwood)]. For strong mortise-tenon joints, wooden furniture producers should consider timbers with large fibre diameters with small lumen.