Abstract
While managing forests for diverse and conflicting outcomes requires great care and patience over many years, the largest expense associated with producing timber products is the cost of harvesting. The contractors responsible for this task must invest in several types of expensive harvesting machinery with limited lifespans, with the goal of minimising their operating cost per tonne including machine ownership costs. Much work has been done on calculating the approximate total cost of owning a machine, given its expected lifespan and other parameters. While extremely use- ful, these calculations neglect several effects that can only be seen by considering a machine as a part of the larger operation. In this paper, we describe several mixed- integer linear programming models, with varied levels of complexity, developed to make decisions regarding equipment replacement. We further describe a prototype decision support tool to be used by machine owners.