Résumé
Wood is present in many cultural heritage objects thanks to its capacity to resist odvantage of the Japanese context where building traditions have been maintained for centuries. The paper deals with mechanical characteristics of aged hinoki (Chamaecyparis obtusa Endl.) wood of Japanese historical buildings especially their Young's modulus and rapture energy. Besides, the paper deals with mechanical properties of accelerated hinoki wood by thermally treated (90,120,150,180℃) for comparison of naturally aged hinoki wood. 3 points bending test were performed in longitudinal (L) and radial (R) directions on small clear wood specimens cut from 8 historical samples and one modern reference considered of high quality by craftsmen. Although aged wood appeared more rigid and stronger than recent wood, after density and humidity corrections were applied no significant variation of L and R rigidity or L strength was observed. The post-linear behaviour, however, was drastically influenced by wood age especially in R direction where the strength and rupture energy decreased markedly with the time elapsed since the wood was processed: aged wood can be considered as safe as long as it is not loaded perpendicular to grain. Similar phenomena were observed on thermally treated wood, quantitative differences are likely to be observed between the various kinds of modifications induced by age.