Template-Type: ReDIF-Article 1.0 Author-Name: Redžo Hasanagić Author-Workplace-Name: Department of Wood Science and Technology, Faculty of Technical Engineering, University of Bihać, Bihać, Bosnia and Herzegovina Title: Optimization of thermal modification of wood by genetic algorithm and classical mathematical analysis Abstract: The use of wood in outdoor conditions is of great importance for the service life of wood, and the process of thermal modification (TM) directly affects the effective value of wood products. This paper presents theoretical and experimental studies of the parameters influencing TM of wood on the changes of its physical and mechanical properties. Experimental studies were performed on thermally modified wood samples for different values of the influential parameters of thermal modification: T (°C), t (h) and ρ (g.cm-3), while the tensile strength was obtained as the output parameter. The obtained experimental data were stochastically modelled and compared with the model obtained by genetic programming. The optimization of processing parameters was performed by classical mathematical analysis and compared with the results obtained by optimization with genetic algorithm. The results of the optimal design parameters obtained by different approaches to optimization were compared and based on that the analysis of the characteristics of the presented techniques was conducted. Keywords: genetic programming, mathematical modelling, mechanical properties, model, tensile strength Journal: Journal of Forest Science Pages: 35-45 Volume: 68 Issue: 2 Year: 2022 DOI: 10.17221/95/2021-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/95/2021-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202202-0001.txt Handle: RePEc:caa:jnljfs:v:68:y:2022:i:2:id:95-2021-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Artsiom Shoshyn Author-Workplace-Name: Chemical Technology and Engineering Faculty, Belarusian State Technological University, Minsk, Belarus Republic Author-Name: Pavel Protas Author-Workplace-Name: Faculty of Forest Engineering, Materials Science and Design, Belarusian State Technological University, Minsk, Belarus Republic Author-Name: Vladimír Štollmann Author-Workplace-Name: Faculty of Forestry, Technical University in Zvolen, Zvolen, Slovak Republic Title: New technological solutions for waterlogged forests by cable yarding Abstract: The article proposes new technological techniques for clear cutting in swampy areas using standing skylines, new construction of yarder and the technology of its operation. As a result of the research on using the Larix 3T-500 cable yarder in winter and summer, the operational negative peculiarities of tower yarder in waterlogged forests were identified. Analysing data on experimental comparative time studies, some measures to reduce the negative effect of the identified features on yarding, felling, lateral yarding were worked out. General recommendations for work performance in swampy logging areas were developed. Based on the initial data for each bundle (yarding distance, lateral yarding distance, average volume of the bundle, etc.) the calculation in the MathCad program was performed and a regression dependence of the yarder performance was obtained. Obtained numerical data on comparative time studies of the working cycle operations were summarized in bar charts, taking into account the loss of time on operations. Keywords: logging, productivity, swamp, special techniques Journal: Journal of Forest Science Pages: 46-60 Volume: 68 Issue: 2 Year: 2022 DOI: 10.17221/94/2021-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/94/2021-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202202-0002.txt Handle: RePEc:caa:jnljfs:v:68:y:2022:i:2:id:94-2021-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Klára Košinová Author-Name: Richard Policht Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Ondřej Matějka Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Vladimír Hanzal Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Miloš Ježek Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Tomáš Kušta Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Author-Name: Vlastimil Hart Author-Workplace-Name: Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Prague, Czech Republic Title: What does the mandible say about wild boar: Ontogenetic development, sexual dimorphism and habitat preferences Abstract: Wild boar (Sus scrofa L.) is one of the most discussed game species, distributed across Europe, therefore the management of this species is considered important. This management should be based on data presented, population quality and preferences and craniometric dimensions show the development of the individual and its prosperity. A sample of 148 male and 153 female wild boar mandibles was studied to compare differences in craniometric measurements, especially to find out wild boar environmental demands and population trends. The width of the caput mandibulae and angle of the mandible showed significant difference between males and females. Measurements analysed with forest area size and other data also showed that larger craniometric dimensions were reached in hunting areas with at least 200 ha of forested area, which may be due to the wild boar's need for safety and vegetative cover in the first months of piglet development with respect to its home range. The development of young wild boar is dependent on rest and shelter in the first months of life. A forest cover of at least 200 ha appears to be sufficient in this respect. Information on habitat preferences and individual development can lead to improvements in wild boar management. Keywords: home range, wildlife management, growth, craniometry, spatial ecology Journal: Journal of Forest Science Pages: 61-71 Volume: 68 Issue: 2 Year: 2022 DOI: 10.17221/128/2021-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/128/2021-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202202-0003.txt Handle: RePEc:caa:jnljfs:v:68:y:2022:i:2:id:128-2021-JFS Template-Type: ReDIF-Article 1.0 Author-Name: Zbyněk Kincl Title: Time study of an all-terrain vehicle (ATV) with a forwarding trailer in the Eagle Mountains in the Czech Republic Abstract: In this research, the time consumption of a CF Moto Gladiator 800 all-terrain vehicle (ATV) with a Vahva Jussi 1500/320 log trailer was researched by the timber forwarding in the forests of the Eagle Mountains in the Czech Republic. The study was conducted in an area with a minimal slope, the terrain was full of obstacles, the average forwarding distance was 480 m, while the random harvesting of trees affected by bark beetle was carried out in the forest. A total of 81 forwarding cycles were measured. The elemental time study method and stepwise regression analysis were applied to develop the forwarding time prediction model. In the study, it was found that the total forwarding cycle time is mostly influenced by the forwarding distance and the number of logs loaded. The total average time per forwarding cycle was 22.53 min, of which an average of 40% was transport time and 60% was time for loading and unloading of logs. An average of 1.43 m3 of timber was forwarded per forwarding cycle. Therefore, the estimated productivity of the ATV forwarder was 3.89 m3.h-1. Keywords: chronometric analysis, forwarding trailer, labour productivity, small-scale machines in forestry Journal: Journal of Forest Science Pages: 72-82 Volume: 68 Issue: 2 Year: 2022 DOI: 10.17221/148/2021-JFS File-URL: http://jfs.agriculturejournals.cz/doi/10.17221/148/2021-JFS.html File-Format: text/html X-File-Ref: http://agriculturejournals.cz/RePEc/caa/references/jfs-202202-0004.txt Handle: RePEc:caa:jnljfs:v:68:y:2022:i:2:id:148-2021-JFS