Assessment of Wood Properties in Lesser-Known Shorea spp. in Sri Lanka

Abstract

Timber species, Beraliya dun (Shorea disticha), Navada dun (Shorea stupularis), Dun (Shorea zeylanica), Yakahalu dun (Shorea trapezifolia), Yakal dun (Shorea astylosa) and Thiniya dun (Shorea congestiflora) are lesser-known timber species belongs to Dipterocarpaceae family in Sri Lanka. Therefore it is important to identify these species and classify according to their timber properties to popularize among people engaged in the timber industry and forest management. In this study wood density, modulus of rupture (MOR), modulus of elasticity (MOE), compression parallel to grain (CNP) and compression perpendicular to the grain (CPG) of six Shorea timber species grown in Rathnapura district in Sri Lanka were investigated. The tests for mechanical properties were performed through the Universal Testing Machine (UTM 100 PC). Determination of the wood anatomical features especially vessels, rays and parenchyma with related to wood physical properties and density also investigated. To study the anatomical features, slides were prepared with small wood section and observed through the microscope using SE premium software and vessel diameter and ray measurements were measured. Six Shorea spp. were identified by using a prepared dichotomous key. The wood density was grouped into four classes as very high, high, medium and low respectively. Out of the six Shorea species, Shorea disticha shows the highest values for MOR and MOE tests and the Shorea trapezifolia was reported as the second highest values for MOR and MOE. Shorea trapezifolia has reported the highest values for CNP, CPG and Tensile strength values. According to the density values, the highest value shown by the Shorea trapezifolia and lowest was from Shorea zeylanica.