Analysis of degradation observed on ancient wooden objects buried underground
Ancient wooden objects were sometimes excavated from the moat of mounded tombs in Japan. Such wooden objects were in the shape of a sunshade, bird, shield, pole, yugi(a bag that holds arrows) among others. Archaeologists discussed the usage of such shaped objects, but no one could clearly explain their use. Some objects were observed using an ordinary microscope. Deterioration by bacteria was found in all parts of the objects. This showed that all the objects had been in water or in heavily water-logged earth. Heavy degradation by soft rot fungi was found at the bottom of the shield and pole shaped objects. It is thought that at one time these objects were erected and partly buried in the ground. A lot of hyphae were found at the bottom of another shield and yugi shaped objects. A small amount of hyphae were additionally found at the top of these objects. These are thought to have been placed on top of the ground. From these results, it is supposed that at the first stage, objects had been placed somewhere on the mound, at the following stage they had fallen into the moat and became buried under the water-logged ground, and at the last stage they came to be excavated.
Keywords: BACTERIA; SOFT ROT FUNGI; HYPHAE; BIODETERIORATION; JAPANESE UMBRELLA PINE; JAPANESE CYPRESS; ARCHAEOLOGICAL WOOD; BURIED WOOD