The aim of the present work was to estimate the productivity and costs of timber harvesting and forwarding during the first commercial thinning of a Scots pine stand. Three harvesting models were introduced and compared: narrow trail, wide access trail, and schematic extraction. The analyzed harvesting equipment consisted of a track mini-excavator (34 kW) with a stroke harvester head (gripping range 4–30 cm), and a farm tractor coupled to a logging trailer with a hydraulic crane. Merchantable timber (roundwood with a minimum diameter of 5 cm inside bark) was harvested from a 25-year-old planted Scots pine stand growing on a grid of 1.4 m × 1.8 m. The study showed the productivity of the mini-harvester ranged from 3.09 to 3.47 m³/PMH₁₅ (productive machine hours plus 15 min), and that of the forwarding equipment to be 4.07 m³/PMH₁₅. The analyzed model of productivity as a function of tree volume and thinning intensity was statistically significant, but the intensity parameter was significant only on plots located along wide access trails (3.7 m) and insignificant on plots located along narrow access trails (2.5 m). The distance between trees was not found to be significant. The calculated net machine costs for the forwarding equipment and track mini-harvester were EUR 36.12 and 52.47 per PMH, respectively. An increase in the usage rate of the harvesting equipment to 80% would reduce the harvesting and forwarding costs to EUR 22.07/m³.

This article compares 2 variants of logging technologies at the motor-manual level: variant A — cutting and delimbing by means of a petrol chainsaw, skidding with the use of a cable winch mounted on a tractor (67–74 kW); variant B — cutting by means of a petrol chainsaw, skidding, debranching and cutting to length by means of a processor aggregated with a farm tractor (61 kW). Direct dosimetry and non-parametric (moving block bootstrap) methods were used in order to specify the characteristics of the collected sets. Bootstrap average values show that the average CO concentration at a skidding tractor operator’s station during early thinning was 2.54 mg×m⁻³. At processor operator’s station it amounted to 10.35 mg×m⁻³. Such results allow to conclude that a higher CO concentration at the above-mentioned 2 work stations was observed during early thinning. In the case of a petrol chainsaw operator, it was observed that the permissible exposure limit (23 mg×m⁻³) was exceeded and the short-term permissible exposure limit (117 mg×m⁻³) was not. The average concentration value for a chainsaw operator working individually during late thinning interventions was substantially lower (15.01 mg×m⁻³), which results from the lack of technological pressure that can be observed while cooperating with a processor operator. The risk increases along with conditions that generate the concentration of exhaust produced by 2-stroke petrol chainsaw engines.

Aim of study: The aim of this research was to analyze the workload of the operators while logging at the motor-manual level in coniferous stands undergoing two tending treatments (early and late thinning). The technologies under the investigation employed a power chainsaw, tractor equipped with a cable winch as well as delimbing and cross-cutting Hypro 450W processor.Area of study, materials and methods: The research areas were located in lowlands and in a mountain range of the Western Carpathians. In the analysis it was assumed that the heart rate at work, expressed in beats per minute, would be an indicator of the workload affecting the human organism. Based on the heart rate, three indicators were calculated: relative heart rate at work (%HRR), 50% level of heart rate reserve, ratio of working heart rate to resting heart rate.Main results: The lowest average workload (typical for light work, %HRR40%) was for the chainsaw operator in early thinning, working with a processor. Cumulative distribution function of the workload at the work station of the skidder operator was characterized by bimodality – an occurrence of two extreme, high and low, workload values.Research highlights: The workload in early thinning was higher by about 7% than in late thinning at the work station of both, the processor operator as well as the chainsaw operator working with a processor.Keywords: logging; tractor processor; heart rate; workload; cardiovascular strain.

Within the majority of forest areas where timber is harvested for industrial and energy purposes, working technologies using highly efficient multi-operational machinery and equipment are employed. The situation is different in fragmented, privately owned forests. In such forests, timber harvesting is mainly based on motor-manual technologies with a high proportion of manual labor, both at the stage of felling and timber processing and at the stage of its transport. The study aimed to characterize the work time structure of the ATV unit driver and his helper, to determine the productivity of this team, and to estimate the risk of injury during manual loading and unloading. Based on the data collected during the field research, the theoretical work time structure, work productivity and costs, and injury risk were estimated as a result of using a professional small trailer equipped with a hydraulic crane for timber forwarding, designed for aggregation with the ATV. The average, calculated productivity of timber forwarding (over an average distance of about 500 m) with manual loading and unloading was almost twice as low as the estimated average productivity of forwarding with mechanical loading and unloading using a hydraulic crane. The total unit costs (including labor costs) of forwarding with manual loading and unloading were almost threefold higher than those of forwarding using a trailer with a hydraulic crane. The use of small forest trailers equipped with a hydraulic crane not only ensures higher productivity and cost effectiveness but also allows reducing (even by several percent) the inconvenience of manual timber handling and the risk of strain of the musculoskeletal system.