The exposure of a tractor operator to noise does not depend solely on the noise produced by the machine, but also on the working conditions, which are constantly changing in forestry. This research was conducted with an adapted IMT 565 DV agricultural tractor in a mixed stand of beech and fir in southwestern Serbia. The results show that the structure of working time changes with increased skidding distance. When the skidding distance is increased from 150 m to 450 m, the share of empty and loaded travel grows from 38% to 50%, resulting in higher noise exposure of a tractor operator. In addition, it was estimated that an increase in the skidding distance from 50 m to 1,000 m results in a noise exposure increase of 2 dB(A). The contribution of the operations of empty and loaded travel and landing work to the total noise level exceeds 90% at 450 meters long skidding distances. However, when assessing worker exposure to noise, it is possible to disregard the major impact factors and inadequately plan the study, which can result in an underestimation or overestimation of exposure to noise. Finally, the results of this study are important for a) a broader understanding of the relationship between the level of noise and exposure time and b) proper planning and performance of measurements characterized by essential and active involvement of forestry professionals.

Keywords: Ergonomics, Forest Operations, Exposure to Noise, Skidding Distance, Time Study.