Eficiência e desempenho operacional de máquinas Harvester e Forwarder na colheita florestal

the knowledge on productive capacity and variable elements that affect machines efficiency is essential for optimizing operations in forest harvesting. this study aimed to evaluate harvester and forwarder machines efficiency and operational performance, for forest exploitation, in the south of the bahia state, brazil. data concerning the number of programmed and effective working hours, as well as reasons for machine downtime, were collected from historical archives, from october 2010 to september 2011. based on these data, the total working hours, operational efficiency, and mechanical availability were calculated. harvester machines showed an average of total working hours of 480 hours and 18 minutes, being 75.6% (363.2 hours) of effective work and 24.4% (117.1 hours) of downtime. forwarder machines showed an average of total working hours of 481 hours and 36 minutes, being 84.7% (407.9 hours) of effective work and 15.3% (73.7 hours) of downtime. the average operational efficiency was of 73.2%, for the harvester, and 82.2%, for the forwarder, and technical downtimes, such as displacements and corrective and preventive maintenances, comprised the main reason for explaining those values. the machines operational performance showed to be adequate, according to time distribution, with 76% and 85% of effective working time, respectively for the harvester and forwarder, and an average of 89% for mechanical availability, for both machines, which showed satisfactory operational efficiency (above 70%).