background and purpose: Logging is an example of the strongest human influence on forest environment because it causes damages to the forest soil and residual trees. The damages that occur during logging are more frequent in the skidding phase compared to the felling and processing phase. Material and Methods: The research was conducted in mixed stands of fir and spruce in the area of eastern Bosnia and Herzegovina. Felling was conducted by chainsaw and extraction by animals, i.e. by two oxen. The following data were collected: tree species, diameter at breast height, pre-bunching zone (0-30 m or 30-60 m), presence of damages, presence of old damages, number of damages, type of damage, damage position and the size of damage. Results: Damages were recorded on 3.32% of residual trees. The average number of damages per damaged tree was 1.08. The same percentage share of damages was recorded on butt end and root collar (38.46%), while damages on root have a share of 23.08%. Stem damages were not recorded. The most common type of damage was debarked tree (61.54%), then squashed bark (23.08%) and debarked and damaged tree (15.38%). It was recorded that the size of damages varied between 60 and 570 cm2. The average size of damage was 222.54 cm2. Statistical analysis using χ2 test showed significant difference in the proportion of damaged trees among different pre-bunching methods, and did not show significant difference in the proportion of damaged trees between different pre-bunching zones. conclusions: It can be assumed that oxen logging causes insignificant damages to residual trees. The results of research will be used as a basis for future studies of residual trees’ damaging during wood skidding.

UDK: 630*36:631.372]:65.015(497.6) This paper presents the research results of the skidding productivity for the Ecotrac 120V skidder in mountainous areas of MU „Igmanˮ in Bosnia and Herzegovina. Time and work study were performed. Multiple regression analysis was used for determination of work operations time consumption depending on influencing factors. The following influencing factors were recorded: the condition of the tractor road (surface), the skidding distance, the winching distance, number of pieces in the load, the volume of the load and the slope of the tractor road. The share of productive time in the total work time is 58.47%. The average value of the influencing factors was established: unloaded travel distance 585.26 m, loaded travel distance 490.49 m, winching distance 16.83 m, number of pieces in the load 5.95, the volume of the load 5.17 m3 and the volume of the piece in the load 1.02 m3. The half-tree length method was used. Standard time for skidding and daily skidding productivity were expressed depending on the skidding distance, while average values were used for other influencing factors. The standard time for skidding was 6.57 min/m3 at a skidding distance of 100 m, i.e. 17.60 min/m3 at a skidding distance of 1,500 m. The daily skidding productivity ranges from 73.07 m3/day at a skidding distance of 100 m to 27.28 m3/day at a skidding distance of 1,500 m. Comparison of the daily skidding productivity with the results of other researches showed that the Ecotrac 120V skidder in this particular case realizes approximately the same skidding productivity under similar working conditions.

UDK: 630*32:658.53(497.6 Olovo) This paper presents an analysis of full-length method used in the phase of sessile oak felling and sorting works. The aim of the research was to establish time consumption during sessile oak felling and sorting works using full-length processing method. The research was conducted in the area managed by Forest enterprise "Šumsko – privredno društvo Zeničko-dobojskog kantona" Zavidovići, Management unit "Šumarija" Olovo, Forest unit "Krivaja", compartment 112. The sampling method was applied for measuring time consumption of work operations. It was established that the share of effective time in total time was 67.12%, the share of unavoidable delay times was 30.79%, and the share of avoidable delay times was 2.09%. Time consumption of tree felling and processing was strongly affected from tree diameter at the breast height (R2=0.656). The achieved results will be used for further research on this topic, which has been unduly neglected in the past few years in the BH forestry. Further research would certainly include ergonomics, economy of work procedures, occupational safety and environmental consequences of forestry work.

UDK: 630*37:630*4     Hauling of heavy and voluminous load (wood) partially through forest wastelands and partially on built roads makes this the most expensive phase, which is also technically the most challenging and most damaging for the forest eco-system. Although it is clear that the realisation of this phase in forest harvesting cannot be completed without certain forest damage, in expert and scientific circles there is general consent that by careful planning and execution in forestry, this damage can be brought down to an ‘acceptable’ level.   One of the reliable indicators of stand damage is the amount of mechanical damage resulting from forest harvesting operations. This damage can be ascertained rather easily and correctly, and the environmental and economic consequences of mechanical damage of standing trees are better known than those resulting from damaging saplings or the soil. (Martinić, 2000).  Pertaining to this, this paper presents the measuring and analysis of mechanical damage to standing trees as a result of hauling trees using the cable skidder ‘Timberjack 225 A’ in the forest unit 17,  Management Unit ‘Gornja Stavnja’, Forest Management Company ‘Gornjebosansko’. The amount of damage was analysed, the place where it occurred on the tree, the level of damage and the surface of the inflicted damage. All the stated analyses were carried out for two ways of skidding wood using a winch (falling and ascending).  Results show, among others, that the stand damage expressed in the percentage of damaged trees of the total tree count is 15.41%, which is the upper limit Martinić (1993) ascertained for this phase of forest harvesting, including the variability of working methods and techniques. Almost half of the damage is stated in the first third of the distance between the skidder path and transport boundary, with the largest amount of damage occurring on the most valuable part of the tree (butt end), especially during slope skidding.

Production of solid fuels from wooden biomass is defined with appropriate energy chain of sup ply. Production procedure of solid fuels from wooden biomass, starting with technology for gathering wood residues and residues from logging up by the system of fuel production (system for milling, crushing, chopping, drying and pressing of wood residues), represents the energy chain of supply of solid fuel from biomass. Every single energy chain of supply and production of certain form of solid fuel from wooden biomass can be uniquely defined with three general criteria. These criteria are: energy efficiency of production, economy of production and environ mental criteria. Efficiency of production is the relation of overall energy consumption per 1 kWh of heating value of produced fuel. When we talk about the economical aspect of production of solid fuels we take into account all production costs per 1 kWh of heating value of biofuel produced. Forest biomass is scattered and the need for its collection and transport require certain consumption of fossil fuel. Consumption of fossil fuel is needed to run mechanization to collect, transport and prepare biomass. Consumption of fossil fuels causes the emission of GHG. Ecological criteria for the estimation of production process of bio energy can be defined as emission of GHG per 1 kWh of heating value of produced fuel. Besides general criteria to estimate the quality of production of energy from biomass, there are specific criteria. Specific criteria regard ing several characteristics are tightly related to applied technologies, potentials and barriers during the use of biomass. This paper analyzes only specific investment in selected chain of en ergy supply. The paper mathematically describes four characteristic cases of solid biofuel production from wooden biomass. These cases are: production of wooden chips from forest biomass with mobile chipper, production of wooden chips from wooden residues transported from sawmill to processing terminal, production of wooden briquette from mill residues transported into briquette factory, production of wooden pellet from mill residues transported into pellet factory. For overall ranking of energy chain of wooden biomass supply and selection of optimum variant, multicriteria optimization and VIKOR method is used.

The development of technology and the means of labour in the technological process of forest harvesting in FBiH mainly depends on the factors related to the specific manner of forest management. The dominant share of mixed tall forests with natural regeneration, the selective manner of management and rather difficult natural conditions have resulted in the application of the cut-to-length method and to a lesser extent, the tree-length and semi-tree-length methods. On the basis of expert classification of the development phases in forest harvesting, it can be noted that wood assortment production in FBiH is currently partially mechanised. With the aim of defining measures for increasing productivity, lowering the costs and a greater humanisation of work, there has been an analysis of the current state of the means of work in all three phases of forest harvesting. The analysis included the following parameters: number of means in different phases, the type, the average age, ownership and technical planned obsolescence. All the data were collected through a survey which included all stakeholders (cantonal forest companies and private contractors). The results showed a satisfactory state only when chainsaws are concerned, i.e. the rather cheap tools. Other equipment (adapted tractors, skidders, trucks, etc.) has largely reached planned obsolescence. Their old age results in a low level of utilisation, i.e. an insufficient amount of working hours per year which eventually leads to a decrease in productivity and increase in expenses. Based on the data, it can be concluded that it is necessary to begin the process of new mechanisation procurement and the replacement of existing, time-worn and technologically obsolete machines with new ones. At the same time, it is clear that, in the conditions of low availability of investment capital and cheap labour force, this has to be a gradual process. In relation with this, the process should start in the most expensive phase - timber extraction, i.e. the phase in which the economic efficiency is unquestionable.

UDK: 630*38:625.711.84(497.6 Sarajevo) The time period of forests opening and construction of forest truck roads in the analyzed area is longer than half of century. In such long time interval different types of vehicles for transport of timber assortments have been applied. Due to this fact technical elements of constructed roads are different. The vehicles currently used for the transport of timber assortments cause an accelerated destruction of forest truck roads due to inappropriate carriage way quality. Besides traffic load the forest truck roads are exposed to permanent atmospheric influences. The above specified and other reasons condition obligatory and regular maintenance and reconstruction of forest truck roads depends on the current condition of forest truck roads as well as on the plans for further use. In this article the condition of forest truck roads in the Forest management regions of Sarajevo Canton has been determined. The most frequent types of damages and causes of their occurrence have been registered. The methods for maintenance and rehabilitation-reconstruction of forest truck roads have been selected and their costs have been calculated. In the time when construction of new kilometers of forest truck roads is more and more rare, timely, adequate and financially justified maintenance of the existing network of forest truck roads is one of the key question for their undisturbed use. On the basis of results obtained in this research the guidelines for the time period and the ways of maintenance of forest truck roads have been given. The application of these guidelines should help in achieving of the best and most economical total results through the long-term use of forest truck roads.

UDK 613.164:711.4]:630*27(497.6 Sarajevo) Noise represents any unwanted, too loud, unpleasant or unexpected sound which negatively affects physical and/or mental health of people. Noise impedes human activities, causes indisposition, irritability, unrest, mental health and behaviour issues, fatigue and sleep deprivation, and even aggressive behaviour with noise volumes above 80 dB. In urban areas, i.e. all the places man lives and works in, the noise people are exposed to daily is called environmental, communal or general noise. Communal noise is a major problem of the closer human environment, especially in urban areas. One reliable means of protection against communal noise is an array of different green plantations. They absorb sound waves and thus lower the level of noise. The larger the density and depth of the plantations, the higher the level of noise protection, and the effectiveness also depends on the character of the plantations (composition, layout of different plants, construction, density, the presence of undergrowth and the shrub layer, height, etc.). In relation to the abovementioned, measuring communal noise in two distinctive locations in Sarajevo was conducted within this paper. The main objective of these measurings is to ascertain, in relation to allowable values (Law on noise protection in Sarajevo Canton), whether and to which degree communal noise exceeds the legally prescribed levels. Apart from that, the framework of this paper strives to ascertain the level to which city greenery affects lowering noise levels. The results show that the measured noise levels in both localities exceed the allowable values regulated by law to a great extent. It is also ascertained that city greenery lowers the noise level by approximately 8%,thus the paper presents recommendations on the method of erecting city greenery for purposes of noise protection.

UDK 630*38:551.311.21          625.711.84:551.311.21 Tractor roads are often, due to un-implementation of appropriate rehabilitation measures, exposed to erosion processes of various intensity. These processes can be particularly expressed upon completion of forest harvesting works if natural conditions also have such character which favors intensification of erosion process. Intensification of erosion processes on tractor roads in post-exploitation period most often occur in cases when surface water appears on ruts. More intensive coverage occurs in cases when tree crowns do not cover tractor roads, i.e. if larger opening (of forest crop) is in close vicinity of tractor road, which enables larger presence of light and more intensive vegetation growth. This document applies erosion process intensity degree method and assessment of degree of coverage or coverage by litter. For assessment we used a scale from 1 to 5 (REBULA, 1991). Erosion intensity degree on observed locations goes from 1,86 to 3,73. Coverage of tractor roads by grass vegetation or coverage by litter is in range from 4,91 to 1,86.

UDK 630*31/*32:621.936.6(497.6 Vareš)           621.936.6:621.892(497.6 Vareš) Chainsaw is the main tool for work, considering the terrain and soil in our country, in the process of the harvesting, and there is a big chance it will be the main tool in the future too. The goal of the research is to determine fuel and lubricant consumption of the chainsaw Husqvarna 372 XP, during the harvesting and making forest wood assortments, on the area of the Public enterprise forest, Vareš, section 37. During the research, 50 trees of the fir and spruce have been felled. Range of the diameter was from 8 to 76 cm, and the volume of the assortments was 86.16 m3. Volumetric method is applied in the measurement of fuel and lubricants, with precise determination of how much fuel it was in the thanks. Analysis showed that there is a strong correlation between consumption of the fuel and lubricant (L/m3) in relation to the size of the breast height diameter. Average fuel consumption in the process of logging and preparation was 0.104 L/m3, while the average consumption of lubricant was 0.023 L/m3. It is necessary to continue to pay great attention to the rationalization of consumption on fuel and lubricants, as well as reducing their harmful effects on humans and environment (introduction and usage of biodegradable fuels and lubricants).

This paper presents the results of research on variation of volume proportion in 1-3 row wood rays in: stem and normal and tension branch wood of beech (Fagus silvatica L.)