Solving the area-restricted harvest-scheduling model using the branch and bound algorithm

There are two broad approaches to the discrete optimization problem of harvest scheduling with adjacency constraints: the unit-restricted model and the area-restricted model. In this paper two formulations of the area-restricted model are solved using the branch and bound algorithm. These formulations are tested on a set of approximately 30 tactical planning problems that range in size from 346 to 6093 polygons over three time periods. Our results show that these formulations can be used to solve small- and medium-sized harvest-scheduling problems optimally, or near-optimally, within reasonable periods of computing time. Solution quality and computing time were found to be sensitive to the initial age-class distribution of the forest and the mean polygon size relative to the maximum opening size. In addition, computation of the opening size constraints was found to be very sensitive to the maximum number of polygons in an opening constraint.