Modeling and solving a logging camp location problem

Harvesting plans for Canadian logging companies tend to cover wider territories than before. Long transportation distances for the workers involved in logging activities have thus become a significant issue. Often, cities or villages to accommodate the workers are far away. A common practice is thus to construct camps close to the logging regions, containing the complete infrastructure to host the workers. The problem studied in this paper consists in finding the optimal number, location and size of logging camps. We investigate the relevance and advantages of constructing additional camps as well as expanding and relocating existing ones since the harvest areas change over time. We model this problem as an extension of the Capacitated Facility Location Problem including the representation of economies of scale on several levels of the cost structure, the possibility of temporarily closing parts of the facilities as well as particular capacity constraints that involve integer rounding on the left hand side. Results for real-world data and for a large set of randomly generated instances are presented.