Background and Purpose: Bark thickness and its share in the volume of roundwood are the most important characteristics of the bark, particularly in the process of timber harvesting, and during scaling of processed logs. Therefore it is very important to have at disposal relatively accurate data regarding these characteristics of bark for particular tree species. The main goal of this paper is to investigate the thickness of the bark and its share in the volume of roundwood of Norway spruce. Materials and Methods: The research was carried out in the area of the Canton 10 of the Federation of Bosnia and Herzegovina and it encompassed 393 trees of Norway spruce from 10 cm to 115 cm of thickness at breast height. Measuring of the mean diameter and double thickness of bark was conducted by section method. In total, 4,647 diameters and bark thicknesses were measured in different relative lengths of stems or in average 10.6 measurements per one stem. Results: As an optimal model for the evaluation of double thickness of the bark of Norway spruce depending on mean diameter of roundwood the function with designated determination coefficient of 0.7142 was selected. The obtained results have confirmed the previously defined relations of investigate characteristics, which are as following: a) with the increase of mean diameter of roundwood (section) double bark thickness is increased from 9.26 mm (thickness class 12.5 cm) to 31.65 mm (thickness class 92.5 cm); b) with the increase of mean diameter of roundwood the share of bark in its volume decreased from 14.26% (thickness class 12.5 cm) to 6.73% (thickness class 92.5 cm). Conclusions: By the actual method of estimating bark thickness or the share of bark in the volume of roundwood of Norway spruce in the forestry of the Federation of Bosnia and Herzegovina a significant error was created which increases with the increase of mean diameter. The obtained results point to the necessity of investigation of these bark characteristics in Bosnia and Herzegovina and represent an inevitable starting point for making adequate tables of bark thickness and its percentage share in the volume of roundwood of Norway spruce.

Forest productive attributes changes over time in native forests has been recognized as crucial challenge for management of uneven aged mixed forests in Bosnia and Herzegovina since middle of the last century. Experimental study has been carried out on set of experimental plots established in mixed stands on mountain Igman in central Bosnia. The most important forest productivity attributes changes based on repeated measures have been monitored over time. The aim of this research was to conduct the post-hoc power analysis for monitored forest attributes: basal area per ha (BA), growing stock per ha (GS) and current annual increment per ha (CAIv). Here are used repeated measures conduced on the 10 experimental plots in two types of mixed stands: fir-spruce and fir-spruce-beech plots (five plots per each type) measured in five (BA and GS) and four (CAIv) occasions in periods between 10–20 years. Analyses of variance (ANOVA) within and within-between repeated measures were applied and power analysis was performed. ANOVA within forest type over time showed highly significant differences for all attributes (α = 0.05, p < 0.001). Here, power analysis for comparison of stand attributes resulted in observed high power values ranged from 82% to 99% (very low risk of Type II errors). Then, ANOVA between two forest types over time showed different significances for forest attributes (α = 0.05, pBA = 0.25, pGS = 0.23 and pCAIv = 0.02). The risks of Type II errors were high for BA and GS (from 66% to 72%) while conclusions for CAIv could be accepted with very low risk (4%). So, the post-hoc power analysis of comparisons of stand attributes between forests types found low power for BA (28%) and GS (34%) and high power for CAIv (96%). These findings confirm importance of proper forest species composition planning in mixed stands related to highest wood productivity and other forest characteristics as biodiversity.

UDK: 630*54:582.475(497.6) In expert activities of forest managements, the forest stand volume is most frequently determined by way of volume tables, the so-called management tariffs. For an evaluation of stand volume using this method, the method of volume tables, it is necessary to know the site class (rating) of the stand for present tree species that is used as an argument for the selection of suitable volume progression (management tariff). The site quality for certain species in mixed stands is determined by comparing the height of trees at certain diameters at breast height (dbh) with the height of appropriate dispositions of height site class curves. In so doing the focus is placed on the ratio between the heights of large diameter trees, and the quality of the stand is rated within an interval of more defined site quality classes. For the purposes of a more objective and simpler  assessment of site quality, there have recently been attempts to make site quality assessments mathematically, using appropriate formulas in which tree heights or average heights by diameter classes and heights determined by mathematical functions of site class curves are used. For economically important tree species in Bosnia and Herzegovina (fir, spruce, beech, sessile oak, black pine and scots pine), the dispositions of height site class curves (and classes) are constructed graphically and mathematical functions for them are not known. A large number of mathematical models that are often used to represent growth trends and that satisfy the needs of height curves is analyzed in this paper with a view to determining the most suitable regression model for simulating height site class curves for fir in high forests in Bosnia and Herzegovina. The expanded Prodan model (with an additional item in the denominator) has been selected as the most suitable one on the basis of statistical indicators of the regression model quality.                                                                                                                          

Forest resources in Bosnia and Herzegovina present rich sites of various non-wood forest products. In the concept of sustainable use of forest resources and assurance the economic, environmental and social effects, non-wood forest products have great importance, especially in the strategic commitments of rural development. However, information on the potentials of non-wood forest products in Bosnia and Herzegovina is very scant, whereas institutional and procedural framework relevant to this sector is underdeveloped. In this paper value chain analysis of non-wood forest products in Bosnia and Herzegovina have been carried out in order to identify the participants in the value chain, their mutual relations, and the analysis of organizational and institutional issues that affect the economic aspects of certain stages of the value chain. Survey method was used for primary data collection in the Federation of Bosnia and Herzegovina, where the relevant information from participants in the chain of non-wood forest products has been obtained. The study included a sample of 156 collectors, who had continuity in the collection and delivery, and 18 companies engaged in purchasing, processing and distribution, which have agreed to participate in the research. For data processing and interpretation of the results classical methods of analysis, synthesis, induction, deduction and comparison, and statistical methods of trend analysis were used. Technique of SWOT analysis was used in order to identify the positive and negative factors, as the basis for defining the strategic direction of non-wood forest products sector development. The obtained results indicate on the presence of numerous problems in the value chain. The share of individual groups of non-wood forest products in the analyzed period is: 50% of berries, 40% of medicinal and aromatic plants and 10% of mushrooms. The average annual growth rate of purchased and processed amounts of medicinal and aromatic plants was 17%, 28% of forest berries, and

UDK: 630*52/*56:519.8(497.6) The aim of this research was to evaluate estimates of the current annual increment of volume (CAIv) variability considering growing stock (V) as structural variable and topographic conditions and Landsat 8 spectral response as environmental variables on hilly and mountainous mixed forests in the northeast Bosnia using multiple linear regressions based on ordinary least squares (MLR) and geographically weighted regression (GWR). Sample data contains geo-referenced forest inventory data, CAIv (m3/ha/year) and V (m3/ha), extracted values from digital terrain model (altitude, slope and aspect) and derived principal components values from Landsat 8 satellite image for forest stands of the management unit located on hilly and mountain positions in protected area Konjuh, Kladanj. Here are applied MLR and GWR using stepwise procedure. MLR and GWR analyses resulted with global coefficients of significant predictors on hilly position. This was expected due to homogenous vegetation and environmental conditions on hilly position. It was found that growing stock affected CAIv the most. Significant improvement of regression modeling is achieved by GWR appliance on sample from mountainous position. There were obtained local influence of growing stock and the first principle component related to green biomass on CAIv. The highest improvement is found for broadleaves CAIv where quantification of local variability of growing stock increased adjusted coefficient of determination about 11% and reduced relative root mean square error for 6%. Local character of green biomass related to conifers CAIv did not improve regression estimation significantly. The broadleaves root mean square error based on GWR was 1.60 m3/ha/year (coefficient of variation more than 30%) which is still high so further modeling including other structural characteristics (stems number, basal area, mixture) as predictors is required. 

UDK: 630*222:582.632.2 (497.6 Sarajevo)           582.632.2:630*5(497.6 Sarajevo) The paper represents a methodological approach in categorization of coppice beech stands in Sarajevo Canton area in relation to their ecological, productive, structural and silvicultural characteristics. For the collection of necessary data, method of temporary experimental surfaces, systematically allocated in squares 200 meters distant from each other has been used, in accordance to design of simple systematic sample. Concentric circles whose radius depend on tree diameter has been used as sample units (STOJANOVİĆ & DRİNİĆ, 1975). Data have been conducted in 659 locations. Stands have been categorized in three categories in relations to predefined criteria of categorization based on stand environment, productiveness, structure, economic value and fostering needs. For each of the categories, average units of basic productive indicators of the stand have been determined: number of trees, basal area, volume and volume increment per year for marked and unmarked, as well as same indicators of marking timber volume and the intensity of felling. Statistical significance of difference between the indicators has been tested by the method of variant analysis. Based on the results, indirect conversion has been recommended for the first stand category, direct and combined conversion for second one, and third category didn't need conversion because they have predominantly protective character

UDK: 630*52:630*24(234.422 Igman) This paper analyses the dynamics of diameter structure and height curves as the main indicators of a simple stand structure, uneven-aged multi-storied fir and spruce stands in the management unit „Igman“ where selective felling is applied based on the principle of positive selection. The data for analysis was collected by periodical measurement during fifty years on two permanent sample plots, forest sections 43 and 58. It has been determined that during the observation period there had been a change in diameter structure in the sense of increase in the proportion of trees in the lower, and decrease in higher diameter classes as well as the increase of tree height in the complete interval of empirical data. It has been concluded that due to selective felling, with higher diameter classes trees included, conditions have been created for the occurrence of new and the development of the existing young crop; diameter structures of a shape characteristic for even-aged stands have gradually assumed the shape characteristic for selective stands. Thus, due to the increase of competition among the trees of lower diameter classes and the felling of lower height and lower quality trees of higher diameter classes, there has been an increase in the height of trees of the same diameter. 

UDK 630*52:582.475(497.6) U radu se analiziraju debljinske i visinske strukture jednodobnih nenjegovanih šumskih zasada crnog bora različite starosti i uslova staništa na karbonatnim supstratima u Bosni. Utvrđene su prosječne procentualne raspodjele broja stabala po debljinskim i visinskim klasama za starosne klase širine 10 godina u okviru pojedinih bonitetnih razreda staništa i njihovi numerički parametri (aritmetička sredina, varijaciona širina, standardna devijacija, koeficijent varijacije, koeficijenti asimetrije i zaobljenosti). Dobijeni rezultati pokazuju veliki varijabilitet prečnika i visine stabala, odnosno intenzivno debljinsko i visinsko diferenciranje stabala ispitivanih zasada.

This paper analyzis the diameter and height structures of even aged stands of Austrian pine (Pinus nigra Arn.) on carbonate substrates in Bosnia of different age and site classes. Average percentile distribution of numbers of trees based on diameter and height classes for the age classes of 10 years within particular site classes and their numerical parameters (average value, width of variability, standard deviation, coefficient of variability, kurtosis and skewness) were established. The obtained results show the large variability in diameter and height of trees, that is, a strong differentiation of diameter and height of trees of tested stands.

UDK 630*54:582.632.2(497.6 Sarajevo) U radu je predstavljen metodski pristup utvrđivanja bonitetne dispozicije staništa izdanačkih šuma bukve na području Kantona Sarajevo. Kao primarna naučna građa poslužili su podaci premjera izdanačkih šuma bukve na ovom području koji su obavljeni u toku 2005 i 2006 godine. Za izravnanje visina testiran je veći broj funkcija koje najbolje simuliraju razvojne tendencije sastojina. Izračunate srednje vrijednosti visina po debljinskim stepenima izravnate su primjenom Chapman- Richardove funkcije koja u odnosu na ostale testirane funkcije daje najprihvatljivije izravnanje i najbolje statističke parametre. Istom funkcijom izravnata je gornja i donja granica variranja visina ( H ± t × Sh ).Na taj način je utvrđen pojas ukupnog variranja visina koji je podijeljen na pet jednakih dijelova koji predstavljaju relativne bonitetne klase. Tako je za svaku sredinu bonitetne klase utvrđen matematički model za procjenu boniteta staništa. Nakon toga, utvrđen je matematički model za izračunavanje parcijalnih relativnih boniteta za svaki par izmjerenih ili izračunatih podataka (D1,3 i H ili Ds i Hs).

In this paper we presented the methodology approach in establishing the height curves for quality classification of the site conditions for beech coppice forests growth in the Sarajevo Canton. Data from the inventory in 2005 and 2006 for this area was used as the basic research material. During the work, many functions, known as “growth functions” were tested. The medium value of the tree height per diameter classes was equalized with Chapman-Richard’s function, which was the best result regarding statistical parameters in comparison with other tested functions. The upper and the lower border of height variation was equalized with this function ( h S t H ⋅ ± ) and the established belt of the total height variation. This belt was spitted in five equal sub belts, which represented relative qualitative classes. In this way we established the mathematical model for quality determination. Each sub belt was mathematically determined as well. Consequently, the mathematical model for calculation (determination) of single tree relative qualitative class was established based on the measured data: the diameter and the height of the tree, (D1,3 and H or Ds and Hs).

In the forestry of Bosnia and Herzegovina in general, a long persisting problem is major presence of mainly low productivity and low-quality outgrown forests or totally bare surfaces. At approximately 50% of the forest surfaces in Bosnia and Herzegovina the production potential of the stands is not optimally utilized, that is, the maximum quantity of quality timber fails to be produced. One of the measures that have been applied in the past in order to overcome this problem is introduction and growth of plantations of autochthonous and allochtonous tree species distinguished for fast growing and high quality timber. Numerous spruce plantations have been raised, including Norway spruce (Picea abies Karst.), Scots pine (Pinus sylvestris L.) and Austrian pine (Pinus nigra Arn.), and in smaller numbers Douglas fir (Pseudotsuga mensiesii Franco.), European larch (Larix europaea L.) Japanese larch (Larix leptolepis Gord.) and American Weymouth pine (Pinus strobus L.). Due to insufficient experience the obtained results differed. The studies on the production and structural characteristics were carried out on the plantations of the Norway spruce, the Scots pine and the Austrian pine in Bosnia and Herzegovina, while on the allochtonous tree species the studies were only partially carried out. This study is an addition to previous such studies. The aim of this study is to analyze and evaluate the productivity of the six conifer species, 3 autochthonous and 3 allochtonous, in a comparative trial in the area of Gostivaćka rijeka.

UDK 630*5:582.475(497.6) U Bosni su tokom dužeg vremenskog perioda podignuti brojni zasadi crnog bora (Pinus nigra Arn.). Provedena istraživanja proizvodnih karakteristika pokazala su da se u predmetnim zasadima nalazi i dalje proizvodi znatna količina drveta. Strukturna izgrađenost i kvalitet stabala još su nepoznati te je kao cilj ovog rada postavljeno utvrđivanje debljinske raspodjele zapremine i zapreminskog prirasta ovih zasada. Rezultat ovog rada pokazaće koja su stabla u zasadima glavni nosioci zapreminskog prirasta, a koja nosioci zalihe pri određenim starostima zasada i uslovima staništa. Pored toga, dobijeni rezultat pružiće orijentacionu sliku debljinske raspodjele očekivanog prinosa na osnovu koje se, pored ostalog, utvrđuje kvalitet i vrijednost prinosa, osnovnog proizvoda šumarstva u drvetu.

U Bosni su tokom dužeg vremenskog perioda podignuti brojni zasadi crnog bora (Pinus nigra Arn.). Provedena istraživanja proizvodnih karakteristika pokazala su da se u predmetnim zasadima nalazi i dalje proizvodi znatna količina drveta. Strukturna izgrađenost i kvalitet stabala još su nepoznati te je kao cilj ovog rada postavljeno utvrđivanje debljinske raspodjele zapremine i zapreminskog prirasta ovih zasada. Rezultat ovog rada pokazaće koja su stabla u zasadima glavni nosioci zapreminskog prirasta, a koja nosioci zalihe pri određenim starostima zasada i uslovima staništa. Pored toga, dobijeni rezultat pružiće orijentacionu sliku debljinske raspodjele očekivanog prinosa na osnovu koje se, pored ostalog, utvrđuje kvalitet i vrijednost prinosa, osnovnog proizvoda šumarstva u drvetu.