Abstract
The farmland policy in Japan must respond to the instability of long-term food supply and demand, though it faces a structural excess of rice products in the short-term. As a solution to this problem, the authors have proposed that abandoned paddy fields be maintained by extensive management in a state where they can be used for farming at any time. In this paper, we aim to evaluate the availability of tree-invaded abandoned paddy fields from an economic viewpoint. A lumbering experiment and case research were carried out, and the relation between the restoration cost of abandoned paddy fields and their ages was modeled based on this research. As a result, the following points were clarified.(1) The cost of restoring abandoned paddy fields exceeds the cost of restoring those invaded only by grass, and the cost of restoring dry farm lands exceeds that of restoring wet farm lands.(2) There is no glaring disparity in aggregate total cost between restoring fields decades after they have been abandoned and the cost of continuing annual maintenance and extensive management designed to maintain the fields in a condition where they can be used at any time.
