Computer Simulation of the GSM Signal Availability for Data Transmission on the Territory of the Forest Enterprise

The work deals with the creation of digital maps of the intensity of GSM/EDGE signal on the territory of the Forest Enterprise at the Technical University in Zvolen, Slovakia. Simulation of electromagnetic radiation intensity was calculated using the prediction program TEMS Parcell, based on technical data of transmitters and receivers, as well as attenuation due to the environment. Calculated values were verified in field measurements by means of testing apparatus placed in the measuring vehicle. The output vector layer contains areas categorized according to the suitability of signal intensity for field use with data or voice services

Mobile Laser Scanning Data Collected under a Forest Canopy with GNSS/INS-Positioned Systems: Possibilities of Processability Improvements

GNSS/INS-based positioning must be revised for forest mapping, especially inside the forest. This study deals with the issue of the processability of GNSS/INS-positioned MLS data collected in the forest environment. GNSS time-based point clustering processed the misaligned MLS point clouds collected from skid trails under a forest canopy. The points of a point cloud with two misaligned copies of the forest scene were manually clustered iteratively until two partial point clouds with the single forest scene were generated using a histogram of GNSS time. The histogram’s optimal bin width was the maximum bin width used to create the two correct point clouds. The influence of GNSS outage durations, signal strength statistics, and point cloud parameters on the optimal bin width were then analyzed using correlation and regression analyses. The results showed no significant influence of GNSS outage duration or GNSS signal strength from the time range of scanning the two copies of the forest scene on the optimal width. The optimal bin width was strongly related to the point distribution in time, especially by the duration of the scanned plot’s occlusion from reviewing when the maximum occlusion period influenced the optimal bin width the most (R2 = 0.913). Thus, occlusion of the sub-plot scanning of tree trunks and the terrain outside it improved the processability of the MLS data. Therefore, higher stem density of a forest stand is an advantage in mapping as it increases the duration of the occlusions for a point cloud after it is spatially tiled

Factors influencing availability of biomass resources and efficiency of its procurement for energy generation. A regional study for the Banská Bystrica Region, Slovakia

The paper presents results of the study analysing the whole chain from methodology of overall and available biomass resources calculations in the region, the most efficient technologies and procurement methods, logistics and economy of biomass supply to the consumer, up to the economic and ecological gains from the conversion of boilers for co-firing wood and brown coal. The study was conducted for the Banská Bystrica region, Slovakia. There is a combined heat and power plant (CHP) in town Zvolen. CHP, originally commissioned in 1954. Overall installed output is 311 MW in heat production and 44, 3 MW in power. Annual supply to the consumers was some 790.000 GJ of heat and 103.000 GJ of electricity during the last few years. Some 60 % of heat production was used for heat and hot water supply to more than 9.000 houses and apartments and 40 % to industrial consumers. It has been using pulverized lignite with up to 1 % of sulphur content as fuel. The content of sulphur in emitted flue gas was as high as 3.500 4.000 mg SO/m³. It causes serious environmental problems in the region. New national limits for greenhouse gases emissions are 1.700 mg SO2 /m³ and 600 mg NOx/m³ with the effect from 1 January 2007. CHP has not been able to achieve them without substantial improvement of technology. Shift from lignite to low-sulphur content brown coal with co-firing of biomass has been identified economically the most feasible and environmentally acceptable solution. Two boilers, each of them with the output of 108 MWt, will be reconstructed for co-firing of pulverized low sulphur content brown coal and biomass. Biomass will share up to 30% of the combusted fuel. The first part of the study was focused on identification of biomass resources for energy use from forestry, wood processing industry and agriculture in the region, with the use of GIS tools. Ecological, economic and operational factors limiting utilization of potential biomass resources were identified and factored into calculations. Logistics of wood supply have been precisely analysed. Costs of wood chips supply from forest residues for three different supply chains have been calculated taking into account ecological, economic and technical limiting factors and transport distances. Also environmental issues have been analyzed. Emissions of greenhouse gases after the reconstruction of boilers will be within the limits in force after 1 January 2008, i.e. 1.400 mg SO2/m³, 600 mg NOx/m³, 250 mg CO/m³ and 50 mg fly ash/m³

Early Stage Forest Windthrow Estimation Based on Unmanned Aircraft System Imagery

Strong wind disturbances can affect large forested areas and often occur irregularly within a forest. Due to this, identifying damaged sites and estimating the extent of these losses are crucial for the harvesting management of salvage logging. Furthermore, the location should be surveyed as soon as possible after the disturbance to prevent the degradation of fallen trees. A fixed-wing type of unmanned aircraft system (UAS) with a compact digital camera was used in this study. The imagery was acquired on approximately 200 hectares where five large windthrow areas had occurred. The objective of the study was to determine the location of the windthrow areas using a semi-automatic approach based on the UAS imagery, and on the combination of UAS imagery with airborne laser scanning (ALS). The results were compared with reference data measured by global navigation satellite system (GNSS) devices. At the same time, windthrow areas were derived from Landsat imagery to investigate whether the UAS imagery would have significantly more accurate results. GNSS measurements and Landsat imagery are currently used in forestry on an operational level. The salvage logging was estimated for each forest stand based on the estimated areas and volume per hectare obtained from the forest management plan. The results from the UAS (25.09 ha) and the combined UAS/ALS (25.56 ha) methods were statistically similar to the reference GNSS measurements (25.39 ha). The result from Landsat, at 19.8 ha, was not statistically similar to the reference GNSS measurements or to the UAS and UAS/ALS methods. The estimate of salvage logging for the whole area, from UAS imagery and the forest management plan, overestimated the actual salvage logging measured by foresters by 4.93% (525 m3), when only the most represented tree species were considered. The UAS/ALS combination improved the preliminary results of determining windthrow areas which lead to decreased editing time for all operators. The UAS imagery shows potential for application to early-stage surveys of windthrow areas in forests. The advantages of this method are that it provides the ability to conduct flights immediately after the disturbance, the foresters do not need to walk within the affected areas which decreases the risk of injury, and allows flights to be conducted on cloudy days. The orthomosaic of the windthrow areas, as a by-product of data processing in combination with forest maps and forest road maps, can be used as a tool to plan salvage logging