A Incorporação de Corredores de Conectividade no Manejo de Florestas Industriais Utilizando a Heurística da RazãoR

Planning models that connect natural forests through corridors formed by industrial forests result in combinatorial mathematical problems that are difficult to solve and demand special techniques. The main objective of this paper is to apply, improve and evaluate the performance of a heuristic method named R-ratio (NOBRE and RODRIGUEZ, 2005), developed to solve forest planning problems that consider exclusively binary variables and are formulated as a model Type I harvest scheduling problem (JOHNSON and SCHEURMAN, 1977 apud CLUTTER et al., 1992, p. 281). The solution’s connectivity deficit was evaluated by a recursive algorithm based on the Graph Theory and dynamic programming techniques. A farm of industrial forest that supplies round wood to a pulp wood company in the State of São Paulo was used as a study case. The method was effective in creating feasible solutions after a few number of interactions, showing inefficiency only in the computational time required. The objective function values of the solutions provided by the heuristic vary from 99.71% to 99.83% of the optimal solution found by a mixed integer linear programming, with an average of 48 interactions.

通过工业林形成的廊道连接天然林的规划模型，会产生难以求解且需要特殊技术的组合数学问题。本文的主要目标是应用、改进并评估一种名为R-ratio的启发式方法（heuristic method）的性能，该方法由NOBRE和RODRIGUEZ于2005年提出，旨在解决仅考虑二元变量且被表述为I型采伐调度问题（Type I harvest scheduling problem）的森林规划问题（JOHNSON和SCHEURMAN，1977引自CLUTTER等，1992，第281页）。解决方案的连通性缺陷通过基于图论（Graph Theory）和动态规划（dynamic programming）技术的递归算法进行评估。以圣保罗州一家为纸浆公司供应原木的工业林场作为研究案例。该方法在经过少量迭代后即可生成可行解，仅在所需计算时间方面表现出低效性。该启发式方法提供的解决方案的目标函数值介于混合整数线性规划（mixed integer linear programming）找到的最优解的99.71%至99.83%之间，平均迭代次数为48次。