Speaker
Description
The aim of the study was to characterise the effects of timber skidding using a prototype battery-powered Salamander 600 4×4 micro-skidder and the impact of this operation on the topsoil layers along the skid trail. The tests were carried out in a young oak stand growing in a mountain broadleaved forest habitat, on sloping terrain with an average slope of 15° (26-27%) and numerous obstacles in the form of stones.
The timber was skidded in two stages. In the first stage, the long logs were pulled individually from the cutting area towards the skid trail. The average distance of timber transport in this stage was 42 m (39-44 m). Then, each load was transported along a 70-metre trail to a storage site by the forest road, where short assortments (bolts) were cut and loaded onto a transport vehicle. The slope gradient in the cutting area was 13° (23%), and on the trail in the longitudinal direction it was 9° (16%). On the skid trail surface, there were many boulders protruding from the ground and several transverse depressions, which effectively limited the speed of the micro-skidder both with and without a load.
During the work, continuous time measurements were performed using the Timing 1.1 application. The application allows the duration of all observed activities to be recorded with an accuracy of 1 second. The duration of each successive observed operation and delays were recorded in a PSION Workabout MX portable field recorder. Before the observation began, the length and diameters of the logs were measured. The Huber formula was used to calculate their volume. The operator had two years of experience both in forestry operations and in operating micro-skidder.
Soil parameters were measured after the first and tenth skidding cycles on three transects perpendicular to the trail axis, located at the beginning, middle and end of the trail. Within each transect, at five points (in ruts, between ruts and at a distance of 1 m from ruts on both sides of the trail), soil compactness was measured with a FieldScope SC 900 static penetrometer, and soil moisture and conductivity were measured with a Spectrum Technologies TDR 350 meter. In addition, soil samples were taken to determine bulk density and moisture content under laboratory conditions.
The average volume of a single load was 0.16 m³ (0.10–0.27 m³). The time required for skidding in productive work time, in the first stage over the described distance within the cutting area, amounted to over 22 min/m³, while the time required for skidding along the trail amounted to over 24 min/m³. The micro-skidder operator needed a total of 47 minutes to skid 1 m³ of timber over an average distance of 112 m. The skidding efficiency in the first stage was 2.89 m³/h and was about 13% higher than the skidding efficiency along the skid trail. A statistically significant increase in soil compactness occurred on the trail in ruts at a depth of up to 20 cm. Changes in other parameters proved to be statistically insignificant.
| Keywords | small-scale mechanization; productivity; soil |
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