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ŠUMARSKI LIST 5-6/2015 str. 41     <-- 41 -->        PDF

both sides of the trail. The area of these wounds in the form of bark peeling is larger than 200 cm2.
The aim of this study is to determine the number and size of wounds to residual trees and the regeneration in a pure beech stand and a mixed stand of beech, fir and spruce, when the half tree length method of felling and processing is applied. In addition, another aim of this paper is to the rank the types of damage occurring during the operations of logging and timber extraction according to their frequency of occurrence.
The research was carried out in November and December 2009 in a pure beech stand and a mixed stand of beech, fir and spruce, in two sample plots located in the Municipality of Čajniče in the Srpska Republic (Figure 1).
Sample plot 1 (SP1) is located in a high mixed stand of beech, fir and spruce on deep acid brown soils. The stand has a group selection structure with the regeneration densely distributed in groups. The shares of species in the mixture are as follows: 67% spruce, 21% beech, 11% fir and other broadleaved species 1%. The area of the sample plot is 47.30 ha, and the wood volume is 416 m3• ha–1. The intensity of felling is 11.95% for conifers and 12.99% for broadleaves. The terrain is steep and dissected, with an altitude ranging from 1000 to 1200 m, a south-southeast aspect, whereas the density of the secondary road network reaches 50.7 m • ha–1.
Sample plot 2 (SP 2) is located in a high beech stand on deep acid brown soil. The area of the sample plot is 55 ha. The group selection forest management method is applied in this stand. The regeneration density is medium, wood volume reaches 345 m3 • ha–1 and the intensity of felling amounts to 13.52%. The terrain is steep, with a slope of up to 70%, the altitude ranges from 750 to 1050 m, the aspect is western and the secondary road network density is 45.8 m • ha–1.
The regeneration density in the two sample plots differed (Table 1).
All trees located in the zone of risk of damage from felling and timber extraction were analyzed, and grouping was performed by tree species and 5 cm diameter degrees.
The operations of felling and processing of wood assortments were performed with a chainsaw. The half tree length method of wood assortment processing was applied along with the group system of work.
The extraction of logs and thick branches was carried out with a tractor Timberjack 240C on earth to skid trails (timber winching) and by skid trail to a truck road and a roadside landing (timber skidding).
All injuries incurred during tree harvesting and timber extraction were measured in the sample plots. In the felling phase, the number of injuries was expressed as the average number of injuries per felled tree, and in the phase of transport as the number of wounds per winching operation. According to the place of formation, the wounds were divided into damage to standing trees and damage to the regeneration. The injuries to standing trees were classified into four groups: damage to the stem (various breakages, tree topping and uprooting), damage to the butt end (bark peeling and other superficial wounds), damage to the crown (breakages, peeling and wounds to branches) and damage to the root collar (bark peeling and other superficial wounds to the root collar). Damage to the regeneration most frequently occurs in the form of breakage of plants and branches, as well as uprooting of the whole tree. Damage to the soil was not analyzed.
The size of wounds (bark peeling) was determined by measuring the height and width of injuries, on the basis of