Comparative Study into the Mechanical Properties of Two Lesser-utilized Timber Species for Furniture and Construction Works

Abstract

Traditional timber varieties employed in Ghana's furniture and construction sectors are diminishing in availability, necessitating the prompt identification and assessment of underutilised timber resources that exhibit similar structural capabilities. Senna siamea (Cassia) and Azadirachta indica (Neem) are notably underutilised, even though they possess significant potential for structural and furnishing uses. Moreover, the intrinsic anatomical and physiological distinctions between sapwood and heartwood could considerably affect their mechanical properties, necessitating thorough assessment. This research examined and contrasted the mechanical characteristics of sapwood and heartwood from S. siamea and A. indica, focusing on modulus of elasticity (MoE), modulus of rupture (MoR), compressive strength parallel to the grain, and shear strength parallel to the grain, while also comparing the findings with recognised commercial timber species in Ghana. A mixed analysis of variance (mixed ANOVA) demonstrated statistically significant distinctions (p < 0.05) between sapwood and heartwood across all assessed characteristics in both species, with heartwood invariably displaying enhanced mechanical performance. A. indica heartwood demonstrated the highest modulus of rupture at 104.25 N/mm² and shear strength parallel to the grain at 19.50 N/mm², while S. siamea heartwood displayed the maximum modulus of elasticity at 13,238.91 N/mm² and compressive strength parallel to the grain at 64.43 N/mm². Comparative analysis revealed that the mechanical characteristics of both species were similar to, and in some instances surpassed, those of commonly used Ghanaian commercial woods. These results confirm S. siamea and A. indica as viable alternative timber options for structural and furnishing uses. The heightened use of these resources may diminish reliance on overharvested commercial species, foster sustainable management of forest resources, and bolster the long-term resilience and competitiveness of Ghana's timber industry.