Skidding is considered to be one of the most stressful works for the forest environment. This paper presented the results obtained from the analysis of soil deformation and selected physical and mechanical parameters of soils on skid trails in the Gorce National Park. The study analyzed two horse and tractor skid trails that are in continuous use in the park. Measurements of parameters were recorded before (summer) and after (autumn) a total of 81 skidding cycles, using a profilometer and a penetrometer, and soil samples were collected for analysis. The measurements obtained from the horse trails indicated that soil compactness was considerably higher in the lower sections of the trails and on the side more loaded by horse traffic and the transported load, which was related to the trail course in the field. The values of penetration resistance were high in the middle of those trails, reaching 6.8 MPa in the layer up to 10 cm. In the tractor trail the values of soil compactness reached 7.62 MPa in the layer up to 10 cm deep and were similar across the width of the trail and deep into the soil profile, with only slight changes observed in the monitored period. As a result of skidding, there were increases in the maximum depth of ruts reaching up to 4.6% on horse trails and up to 10.8% on tractor trails. Soil erosion per 10 m of trail caused by skidding and other natural factors during the study reached 1.314 and 0.390 m3 for the tractor and horse trail, respectively, wherein volume of skidded wood on the tractor trail was 180.1, and 18.1 m3 on horse trails. This confirms that the volume of eroded soil on the trails is determined by the type of skidder used and volume of skidded wood, so it is important to choose the right kind of skidder based on the conditions in which the skidding work will be carried out.
Currently, in Poland, the State Spatial Reference System (SSRS) includes two height reference frames: PL-KRON86-NH and PL-EVRF2007-NH as the Polish implementation of the European Vertical Reference System (EVRF). The deadline for EVRF2007 implementation in Poland, as the only legally permitted height frame, is set at the end of 2023. Because of the administrative division, the implementation was planned in two stages: at the state level (government) and the local level (districts). In the article, the local ones are reviewed, especially regarding the aim of height conversion methods, costs and their progress. As a background, a historical perspective of height systems and frames used in Poland since the beginning of the 20th century is provided. The source of data was the Head Office of Geodesy and Cartography (HOGC), as well as the district surveying departments’ official answers; open documents posted on the Internet, e.g. tender documentation and their results were also analysed.
20 December 2019 in Geomatics and Environmental Engineering
The routing of road corridors in the project of a forest road network in the mountains, along with defining the functions of these roads, is the most important activity in the entire task. It must be preceded by a detailed inventory consisting of many factors characterising the analysed transport area, including economic, technical or environmental factors. This study presents an attempt at the semi-automatic routing of road corridors with the use of GIS technology. The original multi-stage methodology proposed by the present authors is based on raster analyses of the Digital Terrain Model at a resolution of 1 m. The initial stage consists in a preliminary outline of the road network being designed, which is performed by an experienced designer on a contour map. Due to the complicated terrain in mountain areas, the pre-determined road sections are divided into sections for which a generalised direction in the form of a straight line can be indicated. On the basis of the azimuths of these particular direction lines, “targeted” terrain inclinations are calculated for each section separately, which help in decisions concerning the location of the planned road sections. The results obtained indicate the key role of the initial concept of the designed road network, as outlined by the expert, and based on the expert’s professional experience. The problem lies in strongly varied terrain, which forces the designer to use short sections of corridors. This, in turn, significantly increases the amount of work. Good effects of road routing automation can be obtained in areas where land relief is complicated. The designed locations of road sections must be finally verified in terms of terrain inclination along the designated lines, which is essential for the possibility of subsequent detailed design, construction and use of road sections.
Road networks providing access to forest stands, including integral parts such as timber yards, are subjected to significant loads from timber-transporting vehicles. These loads act on the road surfaces, causing them to deform. This study measured and compared the extent of deformation at two timber yards in the mountain forests of southern Poland in the Western Carpathians. These surfaces were constructed as: crushed stone (timber yard in the Ustroń Forest District) and earth (Forest Experimental Station of the University of Agriculture in Kraków). The measurements were carried out using photogrammetric techniques based on aerial surveys by an unmanned aerial vehicle. The measurements were based on networks of reference points with coordinates in local coordinate systems. During the period between the flights, timber was being stored, handled and transported at both sites. The forest administration provided data on the volume of timber delivered to and removed from the storage yard, as well as basic information on the transport vehicles. Soil samples were taken from the surface of both storage yards for laboratory analysis to illustrate working conditions—the soil type, current moisture content, organic matter content and filtration coefficient (from the soil particle size distribution curve) were determined. Digital terrestrial model (DTM) rasters obtained from both aerial surveys at each storage yard were used to calculate differential rasters, which were analysed by plotting cross-sections at selected locations and directions and by calculating the volume of changes in surface geometry between the survey dates. The observed depths of ruts reach 0.4 m at the Ustroń storage yard and 0.5 m at the LZD storage yard, whilst changes involving the displacement of soil from the ruts above the previous surface level are 0.3 m at the Ustroń storage yard and 0.4 m at the LZD storage yard. Greater deformation was observed on the earth surface (with a high organic content and poorer drainage) than on the crushed stone surface, even though the latter was covered by an uncleared layer of mud and waste left over from timber handling. Given the two-site, single-cycle design of this study, this pattern is consistent with—but cannot on its own confirm—a stabilising effect of surface reinforcement; differences in soil moisture, organic content and observation period between the two sites may also have contributed and could not be separated from the effect of surface type alone.