Tactical planning of forest harvesting under different scheduling restrictions

Abstract

Tactical and operational planning are steps that guide the sequence of operations and as they are implemented, impact on the final cost of the wood. Thus, the aim of this study was to carry out the optimized production planning of forest harvesting operations regarding the wood supply for pulpwood production, in order to minimize cutting and transportation costs, through Mixed Integer Linear Programming (MILP). Pinus spp. stand data of a pulp company located in Santa Catarina, Southern Brazil, were used. The forest area consists of 3,714.68 hectares divided into 74 management blocks based on place and age characteristics. The approach to solve this planning was based on the test of three scenarios to minimize costs by applying different constraints: Scenario A) volume balance; Scenario B) maximum scheduling distance between blocks; and Scenario C) volume balance and maximum scheduling distance between blocks. After processing the scenarios, the Spanning tree algorithm was used to define the timber production routes between the blocks and the factory. The scenario A resulted in lower operational cost; however, it presented 49% (142 km) more road network than Scenario C. In contrast, Scenario B presented greater economic risk than the other scenarios, since it presented discontinuous production along the planning horizon. In conclusion, Scenario C was the best cost and risk reduction alternative. This result highlights the importance of properly structuring a management problem, since areas related to the planned activity may present a significant share of the final costs, which can influence the selection of the best solutions.