Análise de sistema de extração de toras longas de Tectona grandis L.f. com trator arrastador adaptado em floresta plantada

Abstract

The objective of this study was to describe and analyze the technical, economic and quality factors of the adapted claw skidder operating cycle in the extraction activity of long logs of Tectona grandis L.f. in the southwest of Mato Grosso. Was evaluated a claw skidder adapted, consisting of a Massey Ferguson agricultural tractor with a hydraulic claw coupled. The data collection was performed in August of 2015, dry season, and in January of 2016, rainy season. The area was divided into 4 extraction distances (up to 20 meters, 20-40 meters, 40-60 meters and over 60 meters). The partial timing method was used to record the individual times of the operational cycle, which consists of the stages of unloaded travel, loading travel, loaded travel, and unloading. The stage that most demanded time was the loading travel by virtue of the logs disorganization inside the stand and, during the rainy period, by the low visualization inside the field; Interruptions were evaluated, mechanical pauses were more frequent. The mechanical availability average (95.75%) and operational efficiency average (87.5%) were considered high. The average productivity (28.95 m³cc/he) can be explained by the time and individual volume of the cycle, and it is inversely influenced by the extraction distance. In the economic analysis, the cost of production (R$ 2.11/m³cc) was considered low in relation to the traditional forest machines used for this same activity. Operating cost had as the highest composition factors, the labor costs and the maintenance cost. Analyzing the sensitivity of the cost of production, productivity had a greater influence on cost variation. When evaluating the quality by Failure Mode and Effect Analysis (FMEA) methodology, it was possible to identify, from the risk index, the stages of loading travel and unloading as the critical ones, and by the same methodology, the critical points of these stages were obtained. Considering the critical points and the analysis of its variables, the quality of the long log extraction system is considered low because there is not a quality program installed, not only in the extraction activity, but throughout the company's harvesting system. There is no investment in evaluation and prevention, thus increasing the costs of failures, which is the only factor that makes up the cost of quality (R$ 89.63 ha). The quality level of the extraction activity of long logs with the claw adapted skidder was considered low due to lack of operator training, of supervision and investments in quality.