Evaluation of Driftwood Properties for Utilization I. Distribution of inorganic substances and salts in driftwood of Sugi (Cryptomeria japonica)

Much driftwood appears on rivers, dams, and at the coast after natural disasters such as heavy rain and typhoons. Driftwood is usually considered a nuisance because of decreasing capacity of dams and disturbance of sea routes. Therefore, it is gathered and disposed of as industrial wastes. However, they are natural bioresources and have a potential for utilization as wood products. In this study, the properties of driftwood salvaged from dams and the sea were evaluated by an elementary analysis using SEM-EDXA method. The results showed that inorganic substances in driftwood from dams were distributed on the end surface of logs and the circumference of driftwood. This means that it is difficult for inorganic substances to move inside of driftwood without a fracture pathway. On the other hand, chlorine in logs immersed in seawater was distributed throughout the sapwood after eight weeks. In heartwood, the distribution of chlorine spread gradually for four weeks and didn't change after that.