Primal-dual methods for sustainable harvest scheduling problems

Timber harvest schedules form the heart of forest resource management. The operations research methodology is applied to resolving the multi-product, multi-period sustainable timber harvest scheduling problems, where area con straints, harvest flow constraints, and ending inventory constraints are im posed. By taking advantage of the model. characterization of block diagonal constraints with multiple sets of network sub-problems and the set of coup ling constraints, an efficient algorithm is explored. Specifically, a prima l-dual method of closed-form solutions is first developed to solve the netw ork sub-problems on the individual basis. Then, a primal-dual steepest-edge algorithm that achieves the global optimum is presented. A numerical examp le illustrating steps of the solution procedure is presented. The proposed algorithm is implemented, and its performance is compared with that of the AMPL-CPLEX package. The proposed primal-dual algorithm achieves, on the ave rage, an approximately four to one reduction in iteration numbers and an ab out eight to one reduction in the CPU execution time.