An aid scheme was established to encourage tree thinning so that, in general, the costs of forest maintenance projects such as thinning were divided up, with national government aid covering around 50 per cent, prefectural governments providing approximately 20 per cent and forest owners approximately 30 per cent. How to reduce costs that fall outside government assistance and how to proceed with tree thinning are major issues, because many local governments are under financial pressure and tree thinning has no economic merits for the individual forest owner. Furthermore, as there is no benefit to be gained from tree thinning and removal of wood, “cut and leave thinning”, whereby the cut material is abandoned in the forest, is increasing.