Optimizing cable harvesting layout when using variable-length cable roads in central Europe

One of the classic operations problems in forest management is the layout of a harvesting system. This paper addresses the design of a harvesting system in areas characterized by steep slopes requiring cable-based harvesting. Layout optimization often involves numerous potential cable alignments and a small number of potential landings. In this paper we develop a model that addresses steep slope conditions found in central Europe that involve a large number of potential landings and cable alignments. In addition we extend existing work by considering variable-length alternatives for each feasible cable alignment. We construct three models, one for single-length cable options and two for variable-length alternatives and test their efficacy in solving 18 different harvesting area problems. We show that one of the variable-length alternative models can be solved in computer times that are competitive with the single-length option model. Overall, the savings that can be attributed to variable-length options are modest, but the alignments found by the variable-length options models are more realistic from forest engineers’ points of view, which will aid in its use and adoption.