ANÁLISE OPERACIONAL E CUSTOS DE SISTEMAS DE COLHEITA DE MADEIRA EM POVOAMENTOS DE EUCALIPTO

Abstract

This study aimed to conduct an operational analysis and costs of two mechanized logging systems in Eucalyptus grandis Hill ex. Maiden stands. The data were collected in areas of the company Klabin S/A, located in Telêmaco Borba, Parana State, Brazil. Were evaluated the Tree-length logging system composed by harvester Caterpillar 320D FM with headstock Log Max 7000C e forwarder Valmet 890.3; and the full-tree system composed by feller buncher Tigercat L870C with headstock Tigercat ST 5702, skidder Tigercat 635C e processor harvester John Deere 903J with headstock Waratah HTH622B. The operational analysis was performed using time and motion studies, being evaluated the elements of operating cycle and determined productivity, operational efficiency, mechanical and technical availability, specific fuel consumption and energy consumption rate of employed machines in logging systems. The costs analysis was performed by determining the operating cost, by the accounting method, cost of production of machines and evaluated systems, and sensibility analysis of the most relevant factors. The results showed that for machines of both logging systems, interruptions accounted for most of the time spent on the operations, occasioned mainly due to stops for corrective maintenance and, consequently, affecting the mechanical and technical availability and operational efficiency. In Tree-length system, the average effective productivity of harvester and forwarder was 31.8 and 33.2 m³cc he?¹, the specific fuel consumption was 167.9 and 71.2 g kW?¹ he?¹ and the energy consumption rate was 5.3 and 2.3 g kW?¹ m³cc, respectively. In the full-tree system, the average effective productivity of feller buncher, skidder and Forestry Processor harvester was 87.0, 119.2 and 33.6 m³cc he?¹, the specific fuel consumption was 143.0, 151.8 and 117.0 g kW?¹ he?¹ and the energy consumption rate was 1.6, 1.3 and 3.5 g kW?¹ m³cc, respectively. In both systems, the productivity can be estimated by employing variables volume and cycle time, and especially by the variable extraction distance in the case of extraction machines. In general, the Tree-length logging system showed operational and economic viability, suggesting the adoption of this system for the evaluated conditions.