Vpliv mirnih con na načrtovanje letne sečnje in spravila lesa

Abstract

The article deals with annual harvest operations (AHO) planning with consideration of disturbance-free areas. We developed two models of binary integer linear programming (BILP) for scheduling work groups to harvest unit areas (HUA) according to the lowest possible cost. Total AHO costs include: harvesting and skidding costs, transportation costs, and machine relocation costs. First model is based on the presumption that harvesting can be planned and executed freely throughout the year. In the second model, scheduling was subject to time restrictions due to disturbance-free areas. 50% of the HUA had time restrictions which led to 16.9% reduction of annual workplace time. In this case, by introducing an extra work group, we can provide for the implementation of the AHO plan. Furthermore, we state that in this situation time restrictions affect the scheduling of work groups and the sequencing of tasks. The increase in total AHO costs can be explained by decreased wood harvesting capacity, increased production costs and higher amortization costs of machines. Available workplace time shortage due to time restrictions can be dealt with by shifting own workers to other tasks. The workforce deficits can be compensated by recruiting subcontractors. We have tested each model on two examples.