Modelagem técnica e econômica de um sistema de colheita florestal mecanizada de toras curtas

• Autor(a) principal: Leite, Elton da Silva
• Data de Publicação: 2012
• Tipo de documento: Tese
• Idioma: por
• Título da fonte: LOCUS Repositório Institucional da UFV
• Texto Completo: http://locus.ufv.br/handle/123456789/730
• topic: Mecanização florestal; Colheita; Harvester; Forwarder; Forest mechanization; Harvest; Harvester; Forwarder; CNPQ::CIENCIAS AGRARIAS::ENGENHARIA AGRICOLA

This study aimed to model a system of cut-to-length mechanized timber harvesting, presented in two chapters. The first objective was to make the technical modeling of productivity and second evaluate economically the return of harvester John Deere tractor, model 1270D for overthrows and trees processing and tractor forwarder John Deere, model 1710D, for logs extraction. The work was executed in the state of Minas Gerais, conducted from January 2010 to May 2011. The areas of planted forests were of hybrid clones of eucalyptus, with 6.0 to 9.5 years. Each experimental unit consisted of four rows with 25 trees each. Experimental units related to factors such as the slope of the terrain and the production of wood from the forest were demarcated, determined by 190 units sampling, ranging from 0.132 to 0.423 m³ per tree without bark and slope up to 36 °, with bucking into logs of 6 m length. Time and motion study were used to evaluate the production process and determine productivity modeling. Costs were divided into fixed and variable. The sensitivity analysis consisted of the variation (± 20%) of the six most important variables and plotted on the diagram spiderplot. Modeling of production costs were performed and obtained internal return rates and machines equilibrium points. Results showed an operating cost for the harvester US $ 145.36 h-1 and for the forwarder US $ 125.24 h-1, 80% of the costs represented by items of maintenance and repairs, cost of fuel and depreciation. A sensitivity analysis showed that with a real economy of 10% in each of the items with the highest expression, it is obtained a reduction of 16% in operating cost of the harvesting system. The harvester, working towards ascent, showed higher productivity in overthrows and trees processing, being on average 6.25% higher than operating on a slope. The forwarder, operating in the displacement loaded downhill has proportioned a greater capacity to extract timber, being on average 20% higher than uphill. The use of modeling allowed determining the performance and operating costs in the activities of harvesting and logging of cut-to-length timber in slope up to 36º.