EFEITO DA ANGULAÇÃO DE FEIXES NO DESEMPENHO OPERACIONAL E NA QUALIDADE DAS CEPAS DE EUCALIPTO NO SISTEMA DE COLHEITA FULL TREE

Abstract

Wood harvesting represents high costs in the production chain, implying the need for greater operational efficiency to meet industry demand in a constant supply flow. Therefore, ensuring operational gains that bring greater agility to machines with high production potential is the key to reducing operating and production costs. This research aimed to evaluate the effect of angulation on the formation of tree bundles when cutting with a feller buncher and dragging with a skidder, on the productive capacity of the machines and on the quality of the eucalyptus stumps for coppicing management and evaluation of system costs. The research was carried out in the region of Itararé, São Paulo state, contemplating the full tree system, in a forest planted with Eucalyptus sp., observed, clonal, aged 9 years in the first rotation, whose wood was destined to the production of cellulose and paper. In the area studied, a shallow cut was carried out, preserving the integrity of the strains, aiming at the regrowth for the formation of a new population in the area. The predominant soil in the region is dark red latosol, with a predominance of flat relief, with a temperate climate, without a dry season and with hot summers. The operational analysis was carried out through a study of times and movements, in the activities of cutting and extraction through the subdivision in partial activities, using the method of timing in continuous times for the determination of the times of the operational cycle of each machine. Productivity was determined in cubic meters per effective hour (m³/he) by quantifying the number of trees cut and extracted, whose values were multiplied by the individual average volume of trees, based on the effective hours of work. The fuel efficiency of the machines was obtained by the ratio between the effective specific consumption of fuel by the machines, in liters per effective hour and the average productivity of wood with bark. The evaluation of the quality of the remaining stumps took place after harvesting the wood, adopting the use of a measuring tape and visual evaluation in quadrants analyzing the parameters: cutting height of the stump, presence of dirt in the stump, damage caused by the wheels. of the machines and presence of shear in the stump. The economic analysis included the parameters of the total operating cost. Data were evaluated using a completely randomized design (DIC). And tested using ANOVA - analysis of variance, with the averages compared by Tukey's test, at a significance level of 5%. The sufficiency of the sampling intensity was verified using the Stein method (2000), while the analyzes were carried out using the Assistat program, version 7.7. The results showed that, in general, the 45º angulation required less total feller buncher operating cycle time and did not significantly impact the skidder operating cycle times. In this way, the productivity of the system in the beam angulation at 45º was more promising, having increased the productivity. Regarding damage to the stumps, the most affected quality parameter was the shearing of the stumps at an angle of 17º, resulting from the lack of sharpening of the feller buncher cutting disc and the accumulation of soil and sawdust inside the disc. The 45º angulation had the best result in terms of strain quality. It was possible to conclude that the arrangement procedure of the tree bundles can impact the wood harvesting operations, being necessary to be considered in the microplanning in order to maximize the gains of the forestry operations.