Genetic variation in wood basic density and moe and their relationship with growth traits in teak (TECTONA GRANDIS L.F.) grown in seed orchards of Kerala

Abstract

A study on the variation in wood basic density and dynamic modulus of elasticity of teak (Tectona grandis L.f.) trees grown in tree improvement trials at various locations in Kerala using destructive and nondestructive testing (NDT) methods was conducted in the College of Forestry, KAU, Vellanikkara, Thrissur during the period 2012-2015. The investigation focused on the variation in physical and mechanical wood properties of teak, and to understand their relationship with growth traits and evaluating the suitability of NDT methods as predictors of timber properties under field conditions. Pilodyn (6J) and Treesonic Microsecond Timer (FAKOPP) were the two NDT equipments used in the study. Teak logs collected from a forest plantation (Elival, Palakkad) were destructively analysed following nondestructive testing with the above equipments. Discs and logs were analysed for within tree variation in Pilodyn pin penetration depth (PPD) and were further subjected to various mechanical tests using UTM as well. Significant variation in mechanical properties, and Stress Wave Velocity (SWV) was observed between the trees sampled. Most of the mechanical properties assessed destructively were found to be highly correlated with SWV. PPD in the periphery of the trees was related to the same in the middle portion of the trees. Pilodyn readings also correlated well with the actual wood basic density analysed destructively. In general, both the NDT instruments were found to be useful in estimation of the respective properties using regression analysis. In standing trees of a CSO (Walayar, Palakkad), an SPA (Nilambur) and two clonal trials (Chettikkulam and Vellikulangara, Thrissur) non-destructive evaluation was repeated. The study revealed high genetic divergence in the wood traits and indicated greater scope for application in tree improvement trials. Growth traits didn’t show any consistency or trend with the differing age of the plantations, nor any convincing relationship with the wood traits. Clusters were also identified for the clones at Walayar and Chettikkulam based on which selection for further breeding programmes can be undertaken