Factors affecting mode I fracture energy of plantation-grown red pine

SummaryMode I fracture energy of premature plantation-grown red pine is discussed, for crack growth in the longitudinal direction. It is demonstrated that fracture energy is influenced by moisture content at test and the direction that stress is applied in the radial-tangential plane. Secondary influences of moisture conditioning and density on fracture energy were observed, with the severity related to the moisture content of the material at test. Discrepancies with findings in the literature are identified and discussed. It is likely that results of this study apply to other conifer species with low extractive contents.