(2014). Sequencing of harvester work during standard cuttings and in areas with windbreaks. Silva Fennica vol. 48 no. 4 article id 1159. 16 p. Highlights• In standard cutting stands and thinning areas with windbreaks there occurred three-activity operational cycles. In mature stands with windbreaks the occurrence of stable sequences supplemented with five-activity cycles was noted. Consequently, the operational time in post-disaster thinning stands should be increased by 55% whereas in mature stands it should be 30% longer in comparison with standard stands. AbstractThe aim of the study was to characterize repetitive cycles of harvester operation. The study was conducted in thinning, mature and post-disaster pine stands. The sequences of the activities characteristic of harvester operation were described as time series. In order to detect the cyclic variable structure of the analysed time series, the methodology of the single spectrum Fourier analysis was applied. In standard stands, post-disaster late-thinning stands and mature stands, the existence of stable operational cycles with the length of three activities was discovered while in post-disaster mature stands additional five-activity operational phases were noted. Described in this way, the lengths of the operational cycles of harvesters working in post-disaster areas were higher by about 55% and 30% respectively, as compared to standard thinning and mature stands.

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 450 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, %HRR<20) was recorded for the processor operator in late thinning (%HRR=16), whereas, the highest one (indicating heavy work, %HRR=48.69>40%) 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. Citation: Leszczyński K., Stańczykiewicz, A. (2015). Workload analysis in logging technology employing a processor aggregated with a farm tractor. Forest Systems, Volume 24, Issue 2, e024, 8 pages. http://dx

Abstract. This research compared the time structure of logger's working day in pine stands during late thinning operations and in similar stands damaged by snowbreak. During operations carried out in stands damaged by snowbreak it is expected that a bigger proportion of time will be spent walking, almost 90%. Consequently the increase in labour consumption while working under these conditions should be the same. The observed increase in time taken was significantly larger than that suggested in the Catalogue of Forest Operations Time Standards for situations when obstacles, or other conditions, not described in the Catalogue occur (30%).

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.

In 1992, in Southern Poland, large areas of Silesian forests were affected by the country’s largest forest fire. Stands introduced in the 9000-ha post-fire region are currently undergoing early thinning. Due to the scope of these treatments, the chance for their timely implementation is ensured only by the application of cut-to-length (CTL) technologies, i.e., with the use of harvesters and forwarders. The use of CTL technologies may, however, be difficult due to the fire history of these stands, which could affect the bearing capacity of their soils. The objective of this study is to determine the accessibility of stands for forest machines in relation to the bearing capacity of the soils and changes in soil compaction in the post-fire sites. Soil compaction was measured in terms of penetrometer resistance in the stands introduced in the post-fire area in question, as well as in control stands growing on five different soil types. It was shown that in the topsoil layer—from 8 to 18 cm thick depending on the soil type—differences in soil compaction in the post-fire and control areas were relatively small. The impacts of the forest fire—manifested as a significant increase in the compaction of the forest soils—were still visible, but only in the deeper layers of the soil profile. In all of the compared pairs of forest compartments located in the stands regenerated after the fire, significantly higher values of cone indexes (CI) were found. The average value of this index in the post-fire stands was 2.15 MPa, while in the control stands it was 1.60 MPa, which indicates that in both groups of stands the bearing capacity of the soils should not limit the accessibility for vehicles used for timber harvesting and extraction.