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Matična publikacijaŠumarski list (Online)
Materijalni opisIlustr., graf. prikazi.
Način izrade datotekeizvorno digitalna građa
Vrstačlanak
OpisU pošumljenim područjima s nedostupnim terenom troškovi pridobivanja drva izrazito su važni. To utječe na razinu mehaniziranosti u šumarstvu. Adaptirani poljoprivredni traktori u širokoj su uporabi, posebice u zemljama u razvoju, kao učinkovita sredstva za prijevoz trupaca ili debla od mjesta sječe do stovarišta. U ovom istraživanju procijenjena je proizvodnost adaptiranog poljoprivrednog traktora s jednobubanjskim vitlom smještenim s prednje strane vozila. Ukupni troškovi tog sustava (traktora i vitla) iznose otprilike 19580 € (Eura). Primijenjena je studija rada i vremena povratnom metodom tijekom dvofazne operacije privlačenja drva. Ispitani su učinci glavnih čimbenika kao što su promjer, visina, obujam i udaljenost privlačenja drva na ukupno vrijeme rada te je napravljena linearna regresijska analiza kako bi se razvio matematički model privlačenja drva. Podaci iz studije vremena pokazali su da privitlavanje debla do primarnog sakupljališta zahtijeva najviše vremena tijekom samog privitlavanja drva uzbrdo, dok je privlačenje debla do stovarišta zahtijevalo najviše vremena tijekom privlačenja drva općenito. Prosječna je proizvodnost sakupljanja drva uz nagib 12.98 m3/sat, a privlačenje drva kretanjem unatrag 14.30 m3/sat. Troškovi sakupljanja drva vitlom uz nagib iznose 10.77 €/sat, a privlačenje drva 11.87 €/sat. Može se zaključiti da se hidraulički sustav s jednobubanjskim vitlom, postavljen s prednje strane adaptiranog poljoprivrednog traktora, može koristiti kao alternativna oprema za pridobivanje drva, posebice kod operacija privitlavanja uzbrdo.In forested areas with difficult terrain conditions the cost of forest harvesting operations is of great importance. This situation affects the technology standards of tools and equipment used in forestry operations. Especially in developing countries modified farm tractors are widely used as effective tools for transporting timber from stump to landing areas. In this study, productivity of the farm tractor with front-mounted single drum winch designed for multipurpose use in forestry operations was evaluated during whole-tree harvesting operation. The total cost of used system (tractor and winch) is approximately 19580 € (Euro). Time and motion study was implemented by using repetitive time measurement technique during two step timber extraction operation. The effects of main factors such as tree diameter, height, volume, and skidding distance on the total operation time were investigated and then linear regression analysis was performed to develop the mathematical models for whole-tree extraction methods. Time study data resulted that winching trees to the prebunching area was the most time consuming work stage in uphill winching method while skidding trees backward to landing was less time consuming work stage in skidding method. The average productivity of uphill winching and skidding whole-tree was as 12.98 m3/hour and 14.30 m3/hour, respectively. The cost of uphill winching and skidding was 10.77 €/hour and 11.87 €/hour, respectively. It can be concluded that the single-drum hydraulic system, which is mounted on the front of the tractor, can be used as an alternative harvesting equipment especially for uphill winching operations in small scale forestry operations.
  
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