A METHODOLOGY FOR ESTIMATING PRODUCTION POSSIBILITY FRONTIERS FOR WILDLIFE HABITAT AND TIMBER VALUE AT THE LANDSCAPE LEVEL

This paper presents a method for estimating production possibility fro ntiers when the objective is joint timber and wildlife habitat product ion. The developed method is a guided-search technique that iterativel y changes stands to new harvest schedules based on the lowest marginal cost of habitat increases. To illustrate the technique, joint product ion of ruffed grouse (Bonasa umbellus) habitat and value from harvesti ng of aspen (Populus tremuloides Michx. and Populus grandidentata Mich x.) stands is considered. A ruffed grouse habitat suitability model, w ith a focus on interspersion of four aspen age-classes, was used to ev aluate habitat conditions. Aspen timber value was evaluated through us e of growth and yield models in combination with discounted costs and revenues. The technique was implemented on a 261-ha land unit in Itasc a County, Minnesota. The resulting production possibility frontier was estimated from analysis of only 2000 possible harvest schedule scenar ios and was convex, indicating increasing marginal habitat costs. Habi tat quality could be increased, to a maximum of 23%, at a cost of 25% of aspen timber value. Using 25 000 random harvest schedules, analysis of the underlying distribution of objective function values indicated that points on the estimated production possibility frontier consiste d of values greatly exceeding the 99.99th percentile.