Abstract
Swietenia macrophylla King is a highly valued tropical tree. Due to restrictions on logging in its native habitats, it has been introduced to several Asian countries. In India, S. macrophylla King has become a popular species among farmers and forest departments. The normal harvesting age followed by the farmers for this species in India is about 30–35 years. However, except for one study on an 88-year-old plantation, no information on young age planation is available. While certain wood properties of this species grown in natural forests are available, complete information on all the mechanical properties of this species is still lacking. Further, very limited information is available on the wood characteristics of trees grown in plantations, particularly those growing outside their native habitat. In this endeavour, the present study was conducted to evaluate the wood properties of 40-year-old S. macrophylla King trees grown in India. The basic density of the wood samples was 0.48 g/cm3 suggesting that the wood is of medium density. The volumetric shrinkage from green to oven dry condition was 10.1% while shrinkage from green to air dry condition was only 4.5%. The modulus of elasticity (MoE, 8.79 GPa) and modulus of rupture (MoR, 80.6 MPa) values obtained are about 20% and 9%, respectively, lower than that of wood from natural forest which have an MoE of 10.96 GPa and an MoR of 88.3 MPa. The compressive strength parallel and perpendicular to the grain was observed to be 37.8 MPa and 13.7 MPa, respectively. Furthermore, the tensile strength parallel and perpendicular to the grain was observed as 95.8 MPa and 6.05 MPa, respectively. The strength values obtained from these tests suggest that the wood is strong, moderately dense and moderately hard. The mechanical properties obtained for 40-year-old trees reaffirms that the timber falls under S6 strength groups.
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