Abstract
Proportion of latewood varies from species to species and from site to site. To understand the stiffness of wood structures, accurate determination of modulus of elasticity (MOE) of the wood is important. In this study, the digital image correlation method was used to analyze the surface strain of wood specimens during the tensile test and to calculate Poisson's ratios of latewood and earlywood. Both digital image analysis (DIA) and X-ray densitometry (XrD) techniques were employed to determine latewood proportion. Good agreement was found between the DIA and XrD results for sapwood proportion. Based on the rule of mixture, the effective MOE can be calculated by the measurement results of MOEs of earlywood and latewood.