Productivity of C Holder 870 F tractor with double drum winch Igland 4002 in thinning beech stands

Research of productivity of C Holder 870 F tractor in thinning beech stands was performed in the area of Forest Administration Bjelovar, Forest Office Velika Pisanica in the compartment 87a of the management unit Bilo Jezero. Timber was skidded uphill. Time study of a cycle was carried out by using collected data and by mathematical–statistical analysis, and it was shown that effective time accounted for 72.98 % and additional time accounted for 27.02 %. Additional time coefficient is 1.37. Time standard for skidding distance from 25 to 250 m ranges between 22.23 and 34.29 min/m3, and daily output, at mean load volume of 0.76 m3, is 21.59 m3/day for skidding distance of 25 m, i.e. 14.00 m3/day for skidding distance of 250 m. Based on official calculation of Hrvatske šume d.o.o. Zagreb for the year 2000 and daily output, the daily unit cost of C Holder 870 F tractor was established and it ranges from 69.16 kn/m3 for skidding distance of 25 m to 106.66 kn/m3 for skidding distance of 250 m