A computer program was developed which provides the necessary information required by landowners to evaluate thinning alternatives in yellow-poplar stands. The program is written Applesoft BASIC for the APPLE II+ microcomputer with a design which emphasizes flexibility and ease of use. The program consists of two primary segments: growth and yield, and economic evaluation. The growth and yield segment is composed of a stand level growth and yield model which consists primarily of a collection of equations specified by Knoebel (1982). The economic evaluation segment calculates two measures of economic performance for before or after taxes. The performance criteria are the present net worth and internal rate of return. Using the computer program developed in the study, optimum thinning regimes were estimated for existing stands of yellow-poplar under a variety of economic and biological conditions. Given a set of benchmark costs and revenues, optimum thinning regimes were estimated for three sites (80, 100, and 120, base age 50). A sensitivity analysis was conducted in which interest rates, thinning costs, and clearcut stumpage values were varied. The optimum regimes expressed varying degrees of sensitivity to changes in the economic parameters. / M.S.