A "mixed ownership system" which combines private and shared ownership systems of land are considered effective as a solution to forest decline. More than the general shared system, effects of high levels of forest recovery can be expected. This research will carry out randomized social experiment in Ethiopia which is facing deforestation, and verify the effects of the system's introduction. This involves changing ownership structure to "mixed ownership" which gives individuals the ownership of only the trees. The unique characteristic of this is that the ownership type will be changed, and an interdisciplinary analysis method will be used. Policy recommendations will also be carried out in relation to resource management policies in developing countries, based on the results. [No. R17-0006]