Effects of truck and trailer operation in the transport of timber assortments in the "Tara" National Park

This paper addresses the issue of the efficiency of truck and trailer operation in the transport of broadleaved and coniferous timber assortments in the area of the "Tara" National Park, across three forest management units. The subject of the research was a Mercedes Arocs 3345 truck. A work study methodology was applied. Work productivity varied depending on working conditions, which were classified as favorable, moderately favorable, and unfavorable. The paper provides correction coefficients for converting work productivity norms from moderately favorable to favorable and unfavorable conditions, as well as correction coefficients for different tree species. Work norms are presented in m³/day, for average load volumes ranging from 20 to 40 m³ and for average log volumes from 0.1 to 0.8 m³. Norms are given for an average calculated transport distance on gravel roads ranging from 3 to 50 km. In order to recalculate distances across different road categories to a standard transport distance, specific calculation coefficients were established.