GozdV 75 (2017) 1 21 Znanstvena razprava 1 Dr. A. Đ., Department of Forest Engineering, Faculty of Forestry University of Zagreb, Svetošimunska 25, Zagreb, Croatia; aduka@sumfak.hr 2 Dr. D. V., Department of Forest Engineering, Faculty of Forestry University of Zagreb, Svetošimunska 25, Zagreb, Croatia; dvusic@sumfak.hr GDK 377.22+114 (045)=163.6 Ocena grobosti terena za spravilo lesa z vlačilci hlodov z vitlom Terrain Roughness Evaluation for Timber Extraction by Cable Skidder Andreja ĐUKA 1 , Dinko VUSIĆ 2 , Tomislav PORŠINSKY 3 Izvleček: Đuka, A., Vusić, D., Poršinsky, T.: Ocena grobosti terena za spravilo lesa z vlačilci hlodov z vitlom, Gozdarski vestnik, 75/2017, št 1. V angleščini, z izvlečkom in povzetkom v slovenščini, cit. lit. 46. Prevod Breda Misja, pregled slovenskega besedila Marjetka Šivic. Ta članek podaja analizo talnih ovir v Zalesini, eni od gozdnogospodarskih enot (GGU) prebiralnih gozdov v hribovito-goratem predelu Hrvaške, kot del opisa terena in klasifikacije, potrebnih za načrtovanje gozdnih del. V predelu visokega krasa je grobost terena izražena z naklonom, različnimi smermi njegove oblikovitosti in s talnimi ovirami, saj je stanje tal zaradi skeletoidne zgradbe manj pomembno za mobilnost vozil. Podatki, ki so na Hrvaškem na razpolago (pedološki zemljevidi, uradni gozdnogospodarski načrti) in se tičejo talnih ovir (kamnitost/skalnatost, druge ovire pa niso omenjene), so še vedno podani kot delež na področje in kot taki dejansko ne razlikujejo med seboj območij, neprimernih za različna gozdarska vozila. Glede na smernice iz literature so bile talne ovire zabeležene na 319 vzorčnih ploskvah, velikih 10 × 10 m na razdalji 100 m. Na vsaki vzorčni ploskvi sta bili izmerjeni višina in pogostost talnih ovir, ki so bile glede na pogostost razdeljene v štiri skupine: 1) posamezne, 2) redke, 3) zmerno pogoste in 4) pogoste; glede na višino so bili določeni štirje višinski razredi: 1) H20 (10-30 cm), 2) H40 (31-50 cm), 3) H60 (51-70 cm) in 4) H80 (> 71 cm). Na osnovi analize deleža skupin talnih ovir, kotov zmožnosti manevriranja in polmera manevrskega prostora vlačilca, ki opisujejo značilnosti njegove mobilnosti, so bile določene tri nove kategorije grobosti terena: 1) les je mogoče vleči preko talnih ovir (20,14% GGE območja), 2) lesa je mogoče vleči, če obidemo ovire (24,54% GGE območja) in 3) potrebna je gradnja vlak (54,16% GGE območja). Ključne besede: talne ovire, prevoznost terena, vlačilec, grobost terena Abstract: Đuka, A., Vusić, D., Poršinsky, T.: Terrain Roughness Evaluation for Timber Extraction by Cable Skidder. Goz- darski vestnik (Professional Journal of Forestry), 75/2017, vol 1. In English, abstract and summary in Slovenian, lit. quot. 46. Translated by Breda Misja, proofreading of the Slovenian text Marjetka Šivic. This paper gives analysis of ground obstacles in one Management unit of selective forests in hilly-pre-mountain- ous part of Croatia, Zalesina, as one part of terrain description and classification required for planning forestry operations. In the area of high karst, terrain roughness is defined in terms of slope, its various direction forms and ground obstacles as soil condition is of minor importance for vehicle mobility due to highly skeletoid soil composition. Available data (pedological maps, official management plans) in Croatia regarding ground obstacles (stoniness/rockiness while other obstacles are left unmentioned) is still given in terms of share per area and as such does not really differentiate areas unsuitable for various forestry vehicles. According to literature guideli- nes, ground obstacles were recorded on 319 sampling plots, each of size 10 × 10 m and with 100 m of distance. Height and frequency of ground obstacles were measured on each sample plot and according to frequency were divided into four groups: 1) isolated, 2) infrequent, 3) moderately frequent and 4) frequent; as well as in four height classes: 1) H20 (10-30 cm), 2) H40 (31-50 cm), 3) H60 (51-70 cm) and 4) H80 (> 71 cm). Based on share analysis of ground obstacle groups, manoeuvrability angles and clearance radiuses of skidder which describe its mobility characteristics, three new terrain roughness categories were defined: 1) skidding timber across ground obstacles is possible (20.14% of MU area), 2) skidding timber while by-passing ground obstacles is possible (24.54% of MU area) and 3) construction of skid roads is necessary (54.16% of MU area). Key words: ground obstacles, terrain trafficability, skidder, terrain roughness 3 Prof. dr. T. P., Department of Forest Engineering, Fa- culty of Forestry University of Zagreb, Svetošimunska 25, Zagreb, Croatia; tporsinsky@sumfak.hr