Efeito de variáveis operacionais na produtividade de um harvester de pneus no desbaste de pinus

Abstract

The aim of this study was to evaluate the effect of terrain slope, tree volume and time of the operational cycle on the productivity of a wheeled harvester in the thinning of a pine stand. The study was in a Pinus taeda L. plantation under first thinning at 10 years old, carried out systematically at 7th row and selective in adjacent rows, conducted in a forestry company in Paraná, Brazil. A motion and time study of the cutting operational cycle was carried out, determining the mechanical availability, operational efficiency and productivity. Models were fitted to estimate the machine productivity in function of average volume of individual trees and time of operational cycle in the different slope conditions. The results showed that the average mechanical availability and operational efficiency were 91% and 83%, respectively. The machine average productivity was 15.4 m3/eh, with no significant difference between the terrain slopes. There was significant increase in productivity of machine at the cut trees with average volume above 0.19 m3. The terrain slope, tree volume and time of the operational cycle variables explained 69% of the harvester productivity in the cutting of pine stands submitted to the first thinning. These information can be used in the planning of forestry operations.