This paper provides a systematic investigation of agricultural systems practiced in the uplands by starting with a formal treatment of the shifting cultivation problem. The optimum rate of use of forested land from society’s viewpoint and from the individual uplander’s viewpoint, given traditional choices between timber production and agricultural production through slash-and-burn farming is likewise investigated. The study explains swidden farming in the context of a standard resource economic model on open access exploitation, the discounting bias and zero valuation of the externalities involved.