1 A model to optimize the value of harvested species in a reduced impact logging concession system constrained by volume in the Brazilian Amazon Luiz Carlos Estraviz Rodriguez Gustavo Chaves Machado José Mauro Magalhães Ávila Paz Moreira ABSTRACT A new Brazilian law and regulation (# 11.284 dated March 02 2006; and # 6.063 dated March, 20 2007) created the Serviço Florestal Brasileiro (SFB) in March 2007. The SFB, or Brazilian Forest Service, manages zones designated for production within federal protected areas, including funding and technical assistance to develop a private concession system. An innovative bidding process, that weights the proposals on both technical quality (60%) and price (40%), guides the selection of future concessioners. The proposals are technically evaluated according to nine quantitative indicators grouped in four criteria: environmental impact; social benefits; efficiency; and locally added value. Concessioners explicitly declare estimates to the nine technical indicators, which are scored and weighted to compute a final single value used to qualify and classify the proposal. Among the nine indicators, there is one that specially deals with the diversity of species harvested to provide the 30 m 3 maximum volume allowed per hectare. The principle follows the hypothesis that, when constrained by volume, the harvesting of a large number of tree species maintains the residual forest diverse and rich, and promotes the introduction of potentially good new tree species in the timber market. Spatial considerations that affect costs and accessibility have also to be considered when choosing the set of trees that will approximately correspond to the desired amount of volume per species to be harvested. This paper describes a two phase solution technique to solve the problem: first, select the number of species and maximum volumes per species by means of a linear programming model; and secondly, locate the best trees in the field using a specially developed GIS routine. The solution technique was applied during feasibility tests implemented by SFB to evaluate the proposals presented to the first forest concession bidding process implemented in Brazil – the 2008 Jamari National Forest Concession Process. Keywords: Linear programming, harvesting model, decision support system, forest management, concession. * Main author address: Departamento de Ciências Florestais – ESALQ/USP Av. Padua Dias, 11 – LCF 13418-900 Piracicaba, SP Brasil