Krč Janez, PhD. Assoc. Prof.

This paper examines the workload of the choker setter in timber extraction operations using the Konrad Mounty 4000 cable yarder. A time study was conducted, measuring the choker setter's heart rate and productivity at varying extraction distances for both »uphill« and »downhill« extraction directions. Heart rate data collected during work was analyzed to evaluate the choker setter's workload in relation to both extraction distance and direction. A total of 257 cycles were recorded across four worksites with similar harvesting performance characteristics. This heart rate data facilitated an analysis of the choker setter’s workload as influenced by field and technological factors.

The results indicate that the workload comprises both physical and mental components and generally decreases with increasing extraction distance. The analysis of the measurements indicates that heart rate variability is significantly greater on »downhill« worksites compared to »uphill« worksites. This is a consequence of the different structure of working time at worksites with different directions of timber extraction, as well as the specific characteristics of the work process that affect the workload of the choker setter. Consequently the study has highlighted some insights that can guide the optimization of the choker setter’s workload as an essential factor in designing an efficient work process.

This paper examines the workload of the choker setter in timber extraction operations using the Konrad Mounty 4000 cable yarder. A time study was conducted, measuring the choker setter's heart rate and productivity at varying extraction distances for both »uphill« and »downhill« extraction directions. Heart rate data collected during work was analyzed to evaluate the choker setter's workload in relation to both extraction distance and direction. A total of 257 cycles were recorded across four worksites with similar harvesting performance characteristics. This heart rate data facilitated an analysis of the choker setter’s workload as influenced by field and technological factors.

The results indicate that the workload comprises both physical and mental components and generally decreases with increasing extraction distance. The analysis of the measurements indicates that heart rate variability is significantly greater on »downhill« worksites compared to »uphill« worksites. This is a consequence of the different structure of working time at worksites with different directions of timber extraction, as well as the specific characteristics of the work process that affect the workload of the choker setter. Consequently the study has highlighted some insights that can guide the optimization of the choker setter’s workload as an essential factor in designing an efficient work process.

Soil conservation during forestry operations is an increasing concern. This study proposes a theoretical model to forecast the depth of ruts associated with harvester trail systems and organisational boundary conditions, with the aim of reducing the harmful impacts of heavy logging machinery. The research combines empirical data on soil penetration resistance and soil water content of six soil types with theoretical rut depth models, emphasising the organisational dimensions of forest operations. Empirical data were gathered from sixteen soil sample plots in Slovenia. Based on this data and existing litterature, six models were developed to show the relationship between soil penetration resistance and soil water content. The maximum harvester trail length was then calculated for each soil type, based on harvest intensity and rut depth models. The findings indicate that modelled rut dept is less than 0.1 m if the soil can withstand a nominal ground pressure of 849 kPa in all analysed soil types. However, modelled rut depth of any soil type will consistently exceed 0.1 m when the soil cannot withstand a nominal ground pressure of 456 kPa. To avoid deeper ruts, it is advisable to plan and use harvester trail lengths of no more than 100 metres at 40% volumetric soil water content when the soil type is unknown. Incorporating soil type data into rut models could be an effective means of predicting rut depth at a given time, thereby boosting the efficiency of forestry operations.

Soil conservation during forestry operations is an increasing concern. This study proposes a theoretical model to forecast the depth of ruts associated with harvester trail systems and organisational boundary conditions, with the aim of reducing the harmful impacts of heavy logging machinery. The research combines empirical data on soil penetration resistance and soil water content of six soil types with theoretical rut depth models, emphasising the organisational dimensions of forest operations. Empirical data were gathered from sixteen soil sample plots in Slovenia. Based on this data and existing litterature, six models were developed to show the relationship between soil penetration resistance and soil water content. The maximum harvester trail length was then calculated for each soil type, based on harvest intensity and rut depth models. The findings indicate that modelled rut dept is less than 0.1 m if the soil can withstand a nominal ground pressure of 849 kPa in all analysed soil types. However, modelled rut depth of any soil type will consistently exceed 0.1 m when the soil cannot withstand a nominal ground pressure of 456 kPa. To avoid deeper ruts, it is advisable to plan and use harvester trail lengths of no more than 100 metres at 40% volumetric soil water content when the soil type is unknown. Incorporating soil type data into rut models could be an effective means of predicting rut depth at a given time, thereby boosting the efficiency of forestry operations.