Planning of forest harvesting operations is one of the key elements of successful forest management. The integration of modern tools and traditional forestry procedures is something that must be done in contemporary forestry. This research investigated the use of multicriteria decision support (AHP) and GIS in choosing the optimal harvesting system for predominantly selection cutting forest management on the example of two Forest Management Units (FMU). Results showed that AHP could be easily integrated into GIS using the extAHP tool and its results could be of help, along with other input data, in choosing the optimal harvesting system. Spatial analysis of raster data in GIS gives a comprehensive insight into the stand and terrain characteristics and shows the relative share of the area proposed for each system. In FMU »Kozara–Mlječanica«, the harvesting system chainsaw-skidder had the highest relative share with 44% of the area, meaning that it is almost the only harvesting system in current use, followed by chainsaw-forwarder (36%), chainsaw-cable yarder (19%), and chainsaw-adapted agriculture tractor (AAT) (1%). The system harvester-forwarder was not used at all, which is understandable considering that FMU »Kozara–Mlječanica« has a higher average slope and higher diameter of trees to be cut than FMU »Prosara«, where harvester-forwarder system accounts for a significant 36% of the area. The dominant system in FMU »Prosara« was chainsaw-forwarder (42%), followed by chainsaw-cable yarder (17%), chainsaw-skidder (4%) and chainsaw-AAT (1%). It should be noted that the presence of chainsaw-skidder system is insignificant. It is replaced by the system chainsaw-forwarder. Traditional harvesting system chainsaw-skidder, which prevails in Bosnia and Herzegovina, should be upgraded with the new technologies and methods. Using tools like multicriteria decision support and GIS could be of great help in that process.

SEEFOR - South-East European Forestry

The extraction of wood from forests is a difficult, risky, expensive, and time-consuming operation, especially in mountainous areas and selective forests. In the forestry of Bosnia and Herzegovina (BIH), winching and skidding of wood assortments is most often done with cable skidders. They are the most applicable because they can handle hilly, mountainous and inaccessible terrain in the compartments that are most common in local forestry. In addition, selective and group-selective forest management systems are dominant, where the manoeuvring of any type of machinery is strictly limited to the skid trails and skid roads. It is a matter of legal and sub-legal regulations and environmental standards. Striving for higher productivity and economy of skidding is ultimately one of the objectives of forest management. Different Timberjack and LKT models of skidders are widely used in BIH. The study was conducted in the area of two public forest enterprises, in compartments 32 (Forest management unit "Vrbanja") and 99 (Forest management unit ““Lješljanica-Maglajska”) with similar stand and relief conditions. The research objects were two skidders, which are used very often in the forestry of BIH, LKT 81T and Timberjack 240A. Skidder LKT 81T was used in compartment 32, where 29 cycles were recorded, during which 212 logs were skidded. Total volume of skidded wood was 159.98 m3 with average volume of 5.52 m3·load-1. Timberjack 240A was used in compartment 99, where 84 cycles were recorded, with 398 logs. Total skidded wood with Timberjack 240A was 657.34 m3, with average volume of 7.83 m3·load-1. Relative share of work operations showed that loaded and unloaded drive had the largest share, onsie In case of LKT 81T loaded drive was 31% and unloaded drive 25%, while for Timberjack 240A skidder loaded drive accounted for 44% and unloaded drive for 37% of productive work time. Average skidding distance for loaded drive was 1080.34 m for LKT 81T and 727.98 for Timberjack 240A. Unloaded drive, manoeuvring drive and loaded drive showed dependence on corresponding distances. With the increase of the distance and volume of the load, the time required for skidding per unit of product increases. In comparable range (up to 900 m), for the same load size, Timberjack 240A achieved lower standard time, i.e., higher productivity than LKT 81T. Using a skidder at longer distances significantly reduces productivity and increases costs. However, planners often decide in such cases to use a cable skidder for wood skidding, knowing that the costs will be higher, which is again a better option than not harvesting parts of the compartment.

Transport drveta je jedna od najskupljih faza u proizvodnji drveta. Obično se sastoji iz tri faze: primicanje, privlačenje i transport drveta kamionima. Prva i druga faza su najvažnije sa aspekta troškova transporta. Oni zavise od udaljenosti mjesta sječe stabala u šumi do najbližeg šumskog puta. Ta udaljenost je distanca privlačenja. Određivanje distance privlačenja je veoma važno za operativno planiranje u šumarstvu zbog toga što je to jedan od indikatora otvorenosti šume. Vrijednost distance privlačenja može biti određena na više načina: mjerenjem na terenu po vlakama, računanjem uz pomoć matematičkih modela i uz pomoć geografskih informacionih sistema (GIS). Distance privlačenja mogu biti geometrijske i stvarne. Geometrijska distanca je dobijena uz pomoć GIS programa, a definisana je kao udaljenost između težišta odjela i najbliže tačke na šumskom putu. Stvarna distanca privlačenja je izačunata na bazi dužina vlaka. Faktor privlačenja je izračunat kao odnos između stvarne i geometrijske distance. On je upoređen sa faktorima privlačenja za slične terenske i reljefne uslove, zbog toga što zavisi od nagiba terena i prisustva prepreka na površini terena. Vlake su snimljene uz pomoć GPS uređaja u 27 odjela na području P.J. „Prosara“ i P.J. „Kozara-Mlječanica“ u šumskoprivrednom području „Kozaračko“, Bosna i Herzegovina.

In the forestry of Bosnia and Herzegovina winching and skidding of wood assortments is usually done with skidders equipped with a cable winch. This is one of the most expensive and technologically challenging activities of forest exploitation. It is...