Wood properties and simulated modulus of elasticity of glulam in three fastgrowing tree species grown in community forests in Yogyakarta, Java Island, Indonesia

Community forests in Indonesia are important suppliers of wood resources for the wood industry. In the present study, stress-wave velocity of stems, log characteristics (taper, green density, and dynamic Young’s modulus), and wood properties (basic density, compressive strength parallel to grain, modulus of elasticity [MOE], and modulus of rupture [MOR]) were investigated for three fast-growing tree species grown in community forests in Indonesia: Acacia mangium Willd., Maesopsis eminii Engl., and Melia azedarach L. Based on the bending properties, the MOE values of laminae (30×150mm in cross-section) and glulam (six layers, 90×150mm in cross-section) were simulated. The mean values of simulated MOE in the laminae were 8.93, 6.82, and 8.63GPa for A. mangium, M. eminii, and M. azedarach, respectively. When the laminae from a species were randomly laminated, the simulated MOE values of glulam were 8.94, 6.82, and 8.66GPa for A. mangium, M. eminii, and M. azedarach, respectively. When laminae with a high, medium, and low MOE were laminated at outer, middle, and inner layers of glulam, respectively, the simulated MOE values of glulam increased by about 5% to 15% compared to the values of a randomly laminated one. It is concluded that glulam with a high MOE can be produced from fast-growing tree species grown in community forests in Indonesia.