ABSTRACT This study aimed to technically evaluate loading and unloading with different wood lengths . Data used were obtained from log harvesting areas of a forestry company in southern Brazil, on operations with loblolly pine logs. The study addressed the analysis of time and motion, being divided into loading, unloading, mooring and unmooring. Four treatments with different log lengths, number of safety straps and number of sampled vehicles were analyzed. Analysis of variance and Tukey test were used to evaluate differences among treatments. Loading and unloading productivity increase of 114% and 92% was observed, respectively, when log length increased from 2.4 m to 7 m. When log length increased, productivity and yield of hours/work also increased. Loading was negatively influenced by the environment where the activity was carried out.

Abstract The progress of mechanization in the forest harvest has reinforced the competitiveness of the production sector in Brazil, although the use of machines in sloping areas is a technical and operational challenge for equipment engineering. This work aims to evaluate the operational and production costs of harvester 911.3 X3M and forwarder 860.4 with auxiliary traction crane in mountainous areas and to analyze the influence of each variable on costs. The data are from areas of eucalyptus repopulation in Minas Gerais. A production cost of USD 4.59 m-³ was observed for the harvester. The forwarder presented a cost of production of USD 2.75 m-³. It is concluded that these machines can operate in mountainous situations with costs equivalent to those of other machines, without significant losses of productivity with the increase of the slope. In addition, the acquisition value of the equipment was the variable that most influenced the operational cost and that the newer the machine, the greater the influence of the price of the fuel, while the more used, the more influence maintenance costs and repairs.

Resumen El avance de la mecanización en la cosecha forestal viene a reforzar los índices de competitividad del sector de producción en Brasil, aunque el uso de máquinas en zonas de pendiente sea un desafío técnico y operacional para la ingeniería de equipos. Este trabajo pretende evaluar los costos operacionales y de producción del harvester 911.3 X3M y del forwarder 860.4 con grúa de tracción auxiliar, en situaciones montañosas y analizar la influencia de cada variable en los costos. Los datos analizados fueron de áreas de repoblación de eucaliptos en Minas Gerais. Se observó un costo de producción de USD 4.59 m-3 (a costos de 2017 en todos los casos) para el harvester. El forwarder presentó un costo de producción de USD 2.75 m-3. Se concluye que estas máquinas pueden operar en situaciones montañosas con costos equivalentes a los de otras máquinas, sin pérdidas significativas de productividad con el aumento de la pendiente. Además, se notó que el valor de adquisición del equipo fue la variable que más influyó en el costo operacional y, entre más nueva la máquina, mayor influencia tiene el precio del combustible; por otro lado, cuanto más usada, más influencia tienen los costos de mantenimiento y reparaciones.