Lignocellulosics are attracting attention as an alternative resource to fossil fuel towards a sustainable society. Among its cell wall components, lignin, which is the second most abundant natural polymer next to cellulose, is expected as a feedstock for the value-added materials. Thus, the development of efficient extraction from the cell wall and its utilization are highly required. Thermochemical treatment such as super- and sub-critical fluid treatment have an effective delignification property and its delignification mechanism has been studied. However, the structure and concentration of lignin vary among the taxonomical species, cell types and morphological region, and the delignification behavior is not uniformly occurred within the cell wall. Thus, in this article, the heterogeneous distribution of lignin in lignocellulosics cell walls will be introduced in the order of moiety, interunit linkages, pendant structure and concentration in each morphological region. Then, the latest research on the topochemistry of delignification during thermochemical treatment will be presented, in particular using super- and sub-critical fluids treatments.

Wood-boring beetles, many of which belonging to the families Bostrichidae and Ptinidae, attack wood by creating tunnels inside, and they spend most part of their life hidden below the surface of wood. For this reason, it is difficult to directly observe their development and behavior, and information on their life history and feeding behavior is scarce. Nondestructive techniques are expected to be applicable to the analyses of development and feeding behavior of beetles inside wood in near natural conditions, minimizing external disturbance. This paper summarizes the author's work on elucidation of the life history and feeding behavior of one of the important wood-boring beetle species, the bamboo powderpost beetle (Dinoderus minutus), using two nondestructive methods, X-ray computed tomography and acoustic emission.

Wood with improved deformable properties such as bending, deflection and ductility, has the potential for new functions in wooden furniture. Therefore, research to improve the deformation properties of wood is essential. In this study, we evaluated deformation properties of wood specimens that were subjected to “steam-bending”, in which longitudinal compression was applied by bending the specimen using the Thonet method, a wood bending technology. Two methods of steam-bending were used: one using the conventional bending mold of the Thonet method, and the other using a bending roller newly devised. Subsequently, after bending, the total length of the specimens decreased, and the static Young's modulus decreased. Vibration tests indicated an increase in the logarithmic decrement owing to the steam-bending process. A decrease in Young's modulus was also observed under the combined Thonet method with a bending roller.