Challenging agent-based simulation for forest operations to optimize the European cable yarding and transport supply chain

Abstract

ABSTRACT In the steep terrain of the European Alps, cable yarding still plays an important role. To maintain low costs of timber harvesting and improve the productivity of cable yarding operations, system integration by mounting of a tower yarder, crane, and processing unit onto a single carrier is the major pathway of innovation. In particular, under mountainous conditions, with small landings at the forest road and high production rates, cable yarding systems require well-coordinated transport to available storage space at the landing. Otherwise, the operation will run out of storage space and be shut down until serviced by a log truck. To investigate the system behavior and determine the overall performance effects, an agent-based simulation model was developed. The impact of the storage capacities, number of trucks employed, weather conditions, and timing of truck orders were evaluated. Cable yarders, trucks, and individual yarding lines form a population of agents placed in the spatial model environment, acting as the top-level agent. To harvest and transport an assumed volume of 52,500 m3 of timber from 65 different harvesting sites with 150 yarding lines, 301 days are required, in the best case. For the worst case, 484 days are required to complete all operations. Early information flow of the storage level at the landing saves a majority of the waiting cost if the storage capacity at the road is low and the number of trucks high, with 2.5 € m−3. The results also show that adopting measures to increase the storage capacity at the landing will lead to less sensitive reactions in the supply chain.