DIGITALNA ARHIVA ŠUMARSKOG LISTA
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ŠUMARSKI LIST 3-4/2020 str. 46     <-- 46 -->        PDF

while only five (5) damaged trees over 60 cm breast height diameter. Other researchers reached the same results.
According to the research by Sabo (2003),the largest number of damaged trees is in the diameter sub-classes of 12.5 cm and 17.5 cm. Veselinović (2012) determined that the largest number of damaged trees is in the diameter sub-class of 12.5 cm, while in the research of Zahirović et al. (2016), the largest number of damaged trees is in diameter sub-class of 17.5 cm.
When we analyse the damage regarding the case of damage, then the largest amountof damage happens during the second phase of forest utilisation i.e. the phase of skidding and winching. According to this research, we recorded 88 trees or 29% that were damaged during felling and processing and 217 or 71% trees during the phase of wood extraction i.e. 157 or 51% trees during the winching phase and 60 or 19% trees during the skidding phase. According to the research by Danilović et al. (2015), the largest number of damaged trees is caused during tree felling (around 50%), while according to the research by Tavankar et al. (2013), the greatestamount of damage happened during the extraction phase (74.4%), while during the felling and processing phases 25.6% damage occurred. The differences that appear in these researches can be the result of various factors.
The analysis of damage per size shows that damage in size of 25.1-100 cm2 is the most common.
The average size of the wound caused during felling is 79.51 cm², the average size of the wound caused during winching is 109.87 cm² and the average size of the wound caused during skidding is 90.75 cm². When we compare these results with the results of other research, then we can spot significant differences.
According to the research by Sabo (2003), the smallest height of the wound from the ground is 10 cm, and the largest is 275 cm.
In the research by Tavankar et al. (2015), the largest number of wounds ranges from 11-50 cm² (46%), and the smallest appears in a range over 201 cm².
In the research by Zahirović et al. (2016),it was determined that the greatest amount of damage appears over100 cm².
According to the research by Veselinović (2012), the average size of wounds caused during approaching with cable-skidder with winch is 1,104 cm², and during extraction with animal is 465 cm².The differences, that appear in these researches, most likely are caused by different stand characteristics and the non-implementation of appropriate protective measures during forest utilisation as protection of trees next to skids.
The most common type of damage according to place of damage, is damage to butt end, and the least common is damage to the root. According to the damage type, the most common is damage that caused the removal of bark.
Vondra and Bogojević (1994) determined that 78% of damage out of all damage occurs on the height of 1 m from the ground.
According to Sabo (2003), the largest amount of damage was on root buttress 84 to 91% while other tree parts (root, stem) were less damaged.
In the research by Zahirović et al. (2016), the largest amount of damage appears in the area of butt end and root collar (72%).
Also, according to the research by Tavankar et al. (2013), the largest amount of damage appears in the area of butt end (57%), and in the research by Veselinović (2012), damage is also on thebutt end (53%).
The largest percentage share of damaged trees is in the category of useful tree (37.8%), then in the category selected tree (36.7%). Similar results were reached by Veselinović (2012) who determined that the largest number of damaged trees is with characteristics of selected trees (44%), while the smallest are those categorised into irrelevant trees (23%). Sabo (2003) determined that there were 46% of damaged selected trees, 30% of useful, and 24% of irrelevant treeson object A, and on object B there were 35% of selected trees, 42% of useful and 23% of irrelevant trees.
The largest share of trees that suffered very severe damage are in the category of trees that have a surface of the wound larger than 150 cm², while the share of those trees that suffered insignificant damage are in the category of trees that have the surface of the wound smaller than 50 cm². In the research by Veselinović (2012), the largest number of damaged trees belongs to severely damaged trees (38%), while the smallest number of damaged trees is in the group of very severely damaged trees (28%). These results are similar to the results reached in this research. According to research by Sabo (2003), there was a percentage of 53% very severely damaged trees on object A, 41% of severely damaged trees and 6% of insignificantly damaged trees. On object B, there was a percentage of 47% of very severely damaged trees, 47% of severely damaged trees and 6% of insignificantly damaged trees.
CONCLUSIONS
Zaključci
During the operations of felling and extraction of wood, unavoidable damage is caused to the remaining trees.In addition, there is damage that could be avoided with the application of proper technology and methods of work, selection of work assets, change of relationship of worker and manager towards work, forest and damage to the stand.
In this research,the total amount of recorded damage is 305 trees, 133 trees of silver fir, 130 trees of European beech, 33 trees of European spruce, 8 trees of rowan and one tree of sycamore.