This thesis is the result of extensive research and numerous measurements carried out by the Gozdno Gospodarska Enota (Forest Service Unit) of Poljane in the district of Rampoha. The measurements were taken in the Fall of 2009, from August through October. The aim of this work was to obtain as much useful information as possible on the suitabiliy of mechanized tree-felling methods on a rocky and mostly hilly terrain strewn with sinkholes, both in older mixed and in rejuvenated forest stands. Our research was done by using two methods of tree-felling. The classical method made use of chain saws, using the models Stihl MS 361 and Husqvarna 372 XP, whereas the mechanized tree-felling was done by using the harvester John Deere 1470D ECO III. The division was parceled out into strata by drawing lots; two of the strata were chosen for measurements. Stratum A 2 was treated using combined tree-felling by chain saw and harvester, while Stratum B 1 was treated using the classical tree-felling method. Before the tree-felling started the district forest manager marked the trees to be felled; all the trees were numbered. Once all the necessary measurements and calculations had been done we analyzed the data in terms of work hours and their productivity. The classical chain saw felling method turned out to have the highest work hour productivity rate of 71.22 %, whereas the rate for the combined technologies approach was 57.65 %, and the lowest rate of 56.4 % was achieved by mechanized tree-felling. Therefore, the classical felling method turned out the best performance on such typical terrain and rejuvenated tracts, although mechanized tree-felling came out ahead in terms of work hours per volume (min per m3). We found mechanized tree-felling to have the advantage for small diameter trees, while the advantage diminished for larger diameter trees, all in terms of work hours per volume.
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