Variations in Mechanical Properties among Trees of the Same and Different Age Classes of Teak (Tectona Grandis L.F) Wood.

The variations in mechanical properties such as modulus of rupture (MOR), modulus of elasticity (MOE) and compressive strength (CS) parallel to grain of Tectona grandis wood aged 15, 20 and 25 years old respectively were evaluated. Six trees from each even aged stand and similar class diameter were selected at the Edo State Forestry plantation sites. Wood samples were collected from outer wood, middle wood and inner wood at 10, 50 and 90 % of the tree merchantable height. The modulus of rupture, modulus of elasticity and compressive strength parallel to grain increased with increase in the age of the tree. The mean values of the modulus of rupture were 76.86, 103.95 and 134.69 N mm-2, modulus of elasticity were 6846.92, 9919.54 and 12845.57 N mm-2 while the mean values for compressive strength parallel to grain were 43.74, 58.47 and 75.36 N mm-2 for 15, 20 and 25 years old Tectona grandis wood respectively. Modulus of rupture, modulus of elasticity and compressive strength parallel to grain increased from pith to bark but decrease from base to top. Analysis of variance conducted to test for significant differences in MOR, MOE and CS parallel to grain for the different age classes, longitudinal positions and radial positions were significant at 0.05 probability level.