Damaging effect of selective cuttings on natural regeneration of uneven-aged fir and beech forest in the area of FM “Oštrelj” Drinić

Abstract

Selective cutting system makes the basis of management of the univen-aged beech and fir (spruce) forests in the mountainous areas of Bosnia and Herzegovina. Within this system there are segregated regeneration groups which are the subject of care measures – cutting. However, in addition to many good features of this type of management, primarily natural regeneration and reduced negative impact on the forest ecosystem, the system has its drawbacks, especially harmful effects on a stand within constant entries on the same surface. This can have a negative effect on the natural regeneration of the stands, which is the basis of this study. Within the surveyed area in the section number 59 in the area of FM “Oštrelj” Drinić sample plots were placed at three locations, namely: on the skid trail T7 (30 sample plots of 2.5 × 2.5 m at a distance of 13.5 m), right next to the skid trail T7 (30 sample plots 1 × 1 m at a distance of 13.5 m) and at a distance of 10 m from the skid trail T7 (30 sample plots 1 × 1 m at a distance of 13.5 m). On the sample plots state of natural regenaration was determined in the context of its number and health status i.e. level of damage from logging, especially machinery. The results showed that there is a clear difference in quality between the natural regeneration plants of the three research locations. Saplings on the skid trail, with all its characteristics, were in worse condition compared to the other two sites, and suffered the biggest negative impacts of logging. Saplings right next to the skid trail suffered some amount of damage from exploitation which resultet that these places had worse quality and quantity of regeneration in relation to the location of 10 m from the skid trail where the existing situation was relatively the best. Also, it was found that the number and quality of saplings was constantly increasing when taking into account the distance from the beginning of the skid trail, regardless of which type of sample plots is concerned. This progression clearly manifested on and right next to the skid trail, while at a distance of 10 m from the skid trail progression is less pronounced as a result of a lot smaller impact of logging in this place. It can be said that there is no significant difference in the quality of natural regeneration (in terms of number and quality of young plants or the degree of damage by logging) after 250 m from the beginning of the skid trail between the location right next to the skid trail and location at 10 m from the skid trail, while regeneration at the skid trail significantly departs up to the end of the skid trail (391.5 meters). When it comes to the type of injury with regard to the cause or part of the plant, results showed that on the skid trail damage is mainly manifested in the form of uprooting, bending and scratches on the bark of the plant, as a result of the great influence of mechanized assets that continually drag assortments at this location (especially in the lower part of the skid trail – on it’s first 200 m). Right next to the skid trail damages were mainly manifested as bark scratches and diseases, with a smaller share of damage caused by insects, while at 10 meters from the skid trail, the biggest damage was made by phytopatological diseases, which is logical because at this site damage from logging occupy a very small share.