1. From the first period of 18th. Century, citizen of Okayama suffered from lack of fuel. This was caused by salt-manufacture which absorbed the fuel from the northern hills where the greater part of of fuels for this fudal teritory was produced. Because at that time the salt-manufacturing developed into a capitalistic industry of comparatively large scale. In spite of the effort of magistrate of Okayama City, fuel could not be supplied to citizen at cheaper price. 2. In 1.9th. Century, salt manufacture absorbed more and more labour from farming villages and capitalistic salters were in league with the executives of the Okayama Clan to corner in fuel. So the executives could not deal the matter as good as it was hoped by people. In this period, inhabitants of the Setouch Coast and the Okayama Plain bought the fuel secretly cut from the common forests by poor farmers. In old times, there would have been some habits in rural communities of Japan to help the poors by allowing the use of common land or giving something to them. Following these habits the secret hewing made by them also seems to be connived. Thus the hills made up of granitic rocks were increasingly denuded especially in the common forests which were the only source of income for the poors. In addition, these districts have the least precipitation in Japan, which makes the restoration of natural vegetation difficult. Thus some of the denuded hills remain as bare hills in these districts to date. As to fertilizer, these economic and social coditions brought about the same results.