Abstract
Forests have two functions; for economy and for public service. These functions, however, are incompatible as they are mutually exclusive. That is, in the functions of forests, the economic ones (i.e. timber producing function) can be obtained only by deforesting the forests themselves while the public service ones (i.e. the function of national land conserving, of water reservoir, of recreation, of oxygen and air purifying, etc.) are available only by maintaining the supply and air forests. This paper is aimed at the development of a theory of harmonizing those two kinds of incompatible functions of forests by an artificial control. To put it more concretely, the purpose of this paper is to construct a theory of optimal division of whole forests into economic and public service usage. It is named as “Theory of Optimal Usage of Forests”. In my opinion, there are two methods to approach this aim: “law of equi-marginal utilities” and “theory of choice”. In this paper, the latter one is applied. From this point of view, the optimal usage of forests is to be defined as such a way of division of whole forests as the production transformation curve and the utility indifference curve just come in contact in the plane of economic forests versus public service forests.
