WOOD SUPPLY OPTIMIZATION IN BRAZILIAN PULP INDUSTRY INVOLVING FORESTRY OUTGROWER SCHEME

ABSTRACT The objective of this study was to identify the best regions for allocation of a forestry outgrower scheme, and the most efficient transportation system, using a mathematical programming model to minimize the wood supply costs in three Brazilian states. The forest outgrower scheme is a partnership between producers and forest companies, without land acquisition by the companies. Forest producers are recognized as an important source of growth for forest production. In order to achieve successful partnerships, the company needs to plan its hiring. In this study, the partnerships are made through formal contracts and the model does not allow breach of contract. Six scenarios were modeled and evaluated based on the total cost of the objective function, average wood cost (USD/m3), average transport distance (km) and processing time. The mathematical model showed its efficiency, effectiveness, and flexibility in generating scenarios to support company managers in the decision-making and to avoid breach of contract. Hiring planning benefits both sides as it ensures the company’s production and provides financial security to forest producers. In addition, the model suggests alternatives such as the differential pricing of wood according to the location of the regions and the formation of homogeneous blocks of contracting/renewal of outgrower schemes around the pulp mill.

摘要 本研究旨在借助数学规划模型，在巴西三个州范围内筛选林业外雇种植合作计划（forestry outgrower scheme）的最优布局区域与最高效运输系统，以最小化木材供应总成本。该林业外雇种植合作计划是生产者与林业公司之间的合作模式，公司无需收购土地。林业生产者是推动林业生产增长的重要力量。为构建稳定高效的合作关系，企业需制定签约招募计划。本研究中的合作关系均以正式合同确立，且模型严禁违约行为。本研究构建了六种情景，并基于目标函数总成本、单位木材平均成本（美元/立方米）、平均运输距离（千米）与加工时长对各情景展开评估。该数学规划模型在生成辅助企业管理者决策的情景、规避违约行为等方面展现出高效性、有效性与灵活性。签约招募计划对合作双方均有益处：既保障了企业的生产需求，也为林业生产者提供了财务保障。此外，该模型还提出了多项优化方案：例如根据区域位置制定木材差异化定价策略，以及在纸浆厂周边构建林业外雇种植合作计划签约与续约的同质化区块。