REVISITING THE MITRA-WAN TREE FARM

The tree-farm model of Mitra and Wan contains novelties: a continuum o f optimal cycles appear for small discounting and the cyclicality surv ives perturbations. To isolate the source of novelties, we study the s implest case: trees live naturally for two periods. This model special izes the general theory of multisector development, under four conditi ons. It becomes a Ramsey type model, augmented by a cross-vintage cons traint: the present acreage under trees, age n, must not be less than the acreage under trees age n + 1, one period hence. Novelties emerge when this constraint bounds the graph of the state-to-control correspo ndence.