“…Stand conditions: extracted timber volume [28,32], soil type and texture [33][34][35], soil moisture content [25], soil's organic matter content, site topography [34,35], stand density and canopy extension [34,35]; 2. Yard logistics: harvesting system, advanced level of logging operation planning, type of machines, logging method [28,32], machine and load mass, tire pressure, vibrations transmitted by vehicles [20], intensity of machine traffic [32], weather conditions during skidding operation, training, experience and expertise of operators as well as planning and worker proficiency [36]; 3. Forest road network characteristics: density of roads and skid trails, slope gradient of skid trail [20].…”