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UDK: 630*52:519.233.5]:582.475(497.6) As the result of sporadic afforestation of not-grown forest land in the past, today in B&H we have significant areas of even-aged forest plants of Scots pine of different ages. Estimate of yield capabilities of habitats/sites of these stands is one of very real issues in even-aged management planning for this tree species. In order to get the clear idea on the value of yield of even-aged stands, it is necessary to conduct long-term researches on permanent experimental plots. Considering that for the results of those researches it is necessary to wait approximately for the duration of production periods for specific tree species, to gain orientation solutions of the problem we can apply short-term researches – using temporary experimental plots set in stands of different ages. Members of the Forest Management Department of Forestry Faculty in Sarajevo in a period from 1985 to 1990 gathered data on temporary experimental plots in existing even-aged forest plantations of spruce, Scots pine and black pine in order to research their growth, structural and production characteristics. Part of those data for Scots pine is used for making of this document. Objective of this research was, based on data on measurement of 77 experimental plots positioned in even-aged not-tended plantations of Scots pine Bosnia-wide, to reach relevant information on the value of wood volume depending on their age and site quality, and to create the most favourable regression model for assessment of volume of large wood value based on known values of the stand taxation elements that could be easily and quickly determined. Besides this, in this document by comparing gained results with appropriate data from other authors we have evaluated productivity of even-aged not-tended forest plantations of Scots pine in B&H.

Process-based models and empirical modelling techniques are frequently used to (i) explore the sensitivity of tree growth to environmental variables, and (ii) predict the future growth of trees and forest stands under climate change scenarios. However, modelling approaches substantially influence predictions of the sensitivity of trees to environmental factors. Here, we used tree-ring width (TRW) data from 1630 beech trees from a network of 70 plots established across European mountains to build empirical predictive growth models using various modelling approaches. In addition, we used 3-PG and Biome-BGCMuSo process-based models to compare growth predictions with derived empirical models. Results revealed similar prediction errors (RMSE) across models ranging between 3.71 and 7.54 cm2 of basal area increment (BAI). The models explained most of the variability in BAI ranging from 54 % to 87 %. Selected explanatory variables (despite being statistically highly significant) and the pattern of the growth sensitivity differed between models substantially. We identified only five factors with the same effect and the same sensitivity pattern in all empirical models: tree DBH, competition index, elevation, Gini index of DBH, and soil silt content. However, the sensitivity to most of the climate variables was low and inconsistent among the empirical models. Both empirical and process based models suggest that beech in European mountains will, on average, likely experience better growth conditions under both 4.5 and 8.5 RCP scenarios. The process-based models indicated that beech may grow better across European mountains by 1.05 to 1.4 times in warmer conditions. The empirical models identified several drivers of tree growth that are not included in the current process-based models (e.g., different nutrients) but may have a substantial effect on final results, particularly if they are limiting factors. Hence, future development of process-based models may build upon our findings to increase their ability to correctly capture ecosystem dynamics.

Debljina kore i njen udio u obujmu oblog drva predstavljaju bitne značajke u tehnološkom procesu pridobivanja drva, posebno u fazi preuzimanja drva. S obzirom da je itekako važno raspolagati s relativno točnim podacima ovih značajki kore za pojedine vrste drveća, osnovni cilj ovoga rada je istražiti navedene značajke kore bukve. Istraživanje je provedeno na području Kantona 10, a obuhvatilo je 678 stabla bukve od 10 do 85 cm promjera na prsnoj visini i od 5 do 40 m visine. Mjerenje srednjeg promjera i debljine kore obavljeno je metodom sekcioniranja, a ukupno je izmjereno 6.403 promjera i debljina kore ili 9,4 mjerenja po jednom stablu u prosjeku. Rezultati su pokazali sljedeće: a) povećanjem srednjeg promjera oblog drva dvostruka debljina kore povećava se od 6,05 mm (debljinski razred 12,5cm) do 20,69 mm (debljinski razred 82,5 cm); b) povećanjem srednjeg promjera oblog drva udio se kore u obujmu eksponencijalno smanjuje od 9,44% (debljinski razred 12,5 cm) do 4,95% (debljinski razred 82,5 cm). ­Utvrđene razlike u komparaciji s drugim autorima koji su istraživali ove značajke kore bukve, ukazuju na važnost nastavka istraživanja i na drugim područjima u BiH. Na taj način bi se dobili pouzdaniji rezultati koji bi bili primjenjivi za cijelu državu ili parcijalno za pojedine njene dijelove, ako se razlika između područja pokaže statistički ­značajnom. Dobiveni rezultati predstavljaju nezaobilaznu polaznu osnovu za izradu tablica kore bukve i novog ­pravilnika o načinu izmjere oblog drva i utvrđivanja količina., Thickness and share in volume of tree and/or round wood represent the most important features of the bark, especially in the process of timber harvesting, during scaling of processed logs. In forestry of Federation of B&H there are no rules or tables for deduction of double bark thickness based on scientific research. Wood assortments tables for our most important tree species, besides a whole series of wood assortments, also contain the category of waste. From a practical point of view this category can be divided into “real waste” and losses. The real waste in this sense consists of various logging slash and sawdust, while the loss constitutes a prescribed method of measuring the dimensions and calculation of volume and the deduction of the double bark thickness. So, it is very important to have relatively accurate data of the bark thickness for certain tree species. Therefore, the objecti ve of this paper is to explore double bark thickness and share of bark in the volume of beech round wood. The research was carried out in the area of the Canton 10 of Federation of B&H. The research included 678 sample trees from 10 cm to 85 cm diameter breast height (DBH) and from 5 m to 40 m of height with 6,403 pairs were measured for double bark thickness and diameter in the middle of the round wood (section). Data of double bark thickness in relation to mid diameter of round wood were equalized by following equation with coefficient of determination R2=0.722.The results of research confirmed the regularities defined in previous research and has shown as follows: a) by the increase of mid diameter of round wood, double bark thickness increases from 6.05 mm (thickness class 12.5 cm) to 20.69 mm (thickness class 82.5 cm), b) by the increase of mid diameter of round wood, bark share in the volume decrease exponentially from 9.44 % (thickness class 12.5 cm) to 4.95 % (thickness class 82.5 cm).The research have indicated the need to use the results and incorporating it into applicable rules of deducting the bark on logs or share of bark in the volume depending on diameter over the bark.

Spatial structure is the horizontal and vertical arrangement of individual trees. It affects many processes in the stand such as stability, production and regeneration. Stand structure parameters are used to describe spatial structure on experimental plots. The paper presents methods that describe the stand structure through three levels of diversity related to position, species and size. Research has been conducted on two experimental plots from the area of Olovo. Referent trees and their competitors were selected on both experimental plots, and competitors were defined by referent tree distance. The aim of this paper is to describe the spatial structure on experimental plot of European beech (Fagus sylvatica L.) and experimental plot of European beech and Scots pine (Pinus sylvestris L.). Indicators of spatial diversity, dimensional diversity and diversity of tree species have been determined to achieve that aim. For each experimental plots are described: horizontal tree distribution (Poisson Distribution, Clapham's Variance – Mean Ratio and Morisita's Index of Dispersion), diameter differentiation (Diameter Differentiation by Füldner and Dominance Index by Hui et al.), species diversity and structural diversity (Species Profile Index by Pretzsch) and species intermingling (Species Intermingling Index by Füldner). Obtained results show that the stand structure of both experimental plots deviates from random distribution. Dimensional diversity parameters indicate stronger intensity of competition for beech trees. Analysis of species diversity showed that beech trees occur in groups or patches, and the other represented species mix more intensive.

U radu su korišteni podaci izmjere 377 modelnih stabala smreke koja su mjerena u oborenom stanju na širem području unutar državnih raznodobnih sastojina u Kantonu 10 (Hercegbosanski Kanton). Za određivanje volumena krupnog drveta stabala primijenjena je metoda sekcioniranja sa sekcijama nejednakih apsolutnih dužina (najčešće od 1 – 2 m). Za izravnanje veličina volumena krupnog drveta od prsnog promjera i visine stabala primijenjena je metoda višestruke regresijske analize. Za procjenu parametara korištenih funkcija, testiranje značajnosti njihovih razlika te provođenje raznih transformacija, kao softversko rješenje korišteni su StatGraphics Centurion XVII. i Statistica 8.0. U cilju izbora „najboljeg“ modela za procjenu volumena krupnog drveta testiran je veći broj poznatih dendrometrijskih dvoparametarskih volumnih funkcija. Kvaliteta izjednačenja i prikladnost testiranih modela ocjenjivani su na bazi utvrđenih veličina osnovnih statističkih pokazatelja za karakteriziranje jačine korelacijskih veza. Najbolje ocjene parametara pokazao je model V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h uz utvrđeni koeficijent determinacije: R2 = 0,99 i veličinu standardne greške regresije Sey=0,24 m3. Testirajući značajnost razlika između stvarnih volumena stabala iz uzorka i volumena tih istih stabala utvrđenih primjenom odabranog regresijskog modela, utvrđen je prosječni postotak odstupanja od 0,44%. To znači da su u prosjeku za 0,44% niži volumeni u odnosu na stvarne volumene na uzorku od 377 stabala smreke, što ukazuje da je ovaj regresijski model upotrebljiv za primjenu u praktičnom radu, jer je taj prosječni postotak manji od 1%.

Forest composed of Picea abies L., Abies alba Mill. and Fagus sylvatica L. cover a large area in the European mountain regions and have a high ecological and socio-economic importance as they supply many ecosystems services. Because of climate change, these forests are exposed to warming, and this effect increases with elevation, which may impact their delivery of goods and services. Previous studies did not find significant changes in the overall productivity of these species over the last 30 years, but they observed changes in species competitiveness at the species and tree levels. In this study, we aimed to link previous results on tree, species and stand level growth in spruce-fir-beech mixed mountain forests by analysing species size distribution dynamics under different climate conditions and their effect on stand growth. We developed a matrix model based on data from 76 long-term experimental plots distributed throughout Europe. We used the change in stand basal area to explore whether temperature modifies species size dominances and proportions, whether the temperature effects on changes in species basal area depend on species size dominance, and whether the effect of species size dominance on changes in the stand basal area varies with temperature. Our results showed that annual mean temperature is an important climatic driver of species dynamics in spruce-fir-beech mixed mountain forests, such that stand basal area growth was favored by higher temperatures, particularly due to positive responses of silver fir which were greater than negative effects of temperature on European beech. The high temperatures also favored the size-dominance of silver fir, while European beech tended to have smaller diameters, independent of the temperature. We also found that the identity of the size-dominant species also influenced changes in stand basal area, with the highest or the lowest changes when Norway spruce and European beech were the size-dominant species, respectively. Silver fir was less influenced by the identity of the size-dominant species than by temperature. Therefore, although mixed mountain forests of spruce-fir-beech were found to be resilient systems in terms of stand productivity, we conclude that increasing temperatures may modify species dynamics and consequently silvicultural interventions will be needed to control species proportions and dominances.

Developing "climate smart forestry" (CSF) indicators in mountain forest regions requires collection and evaluation of local data and their attributes. Genetic resources are listed among the core indicators for forest biological diversity. This study is a report on the evaluation of the standing genetic diversity within and across 12 pure beech stands (Fagus sylvatica L.) established within the CLIMO (CLImate Smart Forestry in MOuntain Regions) project, using nuclear microsatellite markers. The sampling sites were set along the species' distribution range, including the Balkan region and extending towards the Iberian Peninsula. Cores or leaves from 20 to 23 old, mature trees per plot were sampled for DNA analysis. Genetic diversity indices were high across the range (H-E = 0.74-0.81) with the highest in the Bosnian Mountains. Genetic divergence increased significantly with the geographical distance (Mantel test: r = 0.81, p < 0.001). Most of the stands exhibited an excess of heterozygotes, with the highest value at the Hungarian site (H-O/H-E = 1.177), where beech persists close to the eastern xeric limit of the species' distribution. STRUCTURE revealed within-region differentiation in the Balkan Peninsula, where the Bulgarian stand was the most outstanding. The genetic parameters of each stand could be assessed as a resource for CSF indicators interpreted especially at the local level. The authors acknowledge the networking support by the COST (European Cooperation in Science and Technology) Action CLIMO (Climate-Smart Forestry in Mountain Regions -CA15226) financially supported by the EU Framework Programme for Research and Innovation HORIZON 2020. Michal Bosela was additionally supported by the Slovak Research and Development Agency (project Nos. APVV-15-0265 and APVV-19-0183).

Centro de Investigación Forestal (CIFOR), Spruce-fir-beech mixed forests cover a large area in European mountain regions, with high ecological and socio-economic importance. As elevation-zone systems they are highly affected by climate change, which is modifying species growth patterns and productivity shifts among species. The extent to which associated tree species can access resources and grow asynchronously may affect their resistance and persistence under climate change. Intra-specific synchrony in annual tree growth is a good indicator of species specific dependence on environmental conditions variability. However, little attention has been paid to explore the role of the inter-specific growth asynchrony in the adaptation of mixed forests to climate change. Here we used a database of 1790 tree-ring series collected from 28 experimental plots in spruce-fir-beech mixed forests across Europe to explore how spatio-temporal patterns of the intra- and inter-specific growth synchrony relate to climate variation during the past century. We further examined whether synchrony in growth response to inter-annual environmental fluctuations depended on site conditions. We found that the inter-specific growth synchrony was always lower than the intra-specific synchrony, for both high (inter-annual fluctuations) and low frequency (mid- to long-term) growth variation, suggesting between species niche complementarity at both temporal levels. Intra- and inter-specific synchronies in inter-annual growth fluctuations significantly changed along elevation, being greater at higher elevations. Moreover, the climate warming likely induced temporal changes in synchrony, but the effect varied along the elevation gradient. The synchrony strongly intensified at lower elevations likely due to climate warming and drying conditions. Our results suggest that intra- and inter-specific growth synchrony can be used as an indicator of temporal niche complementarity among species. We conclude that spruce-fir-beech mixtures should be preferred against mono-specific forests to buffer climate change impacts in mountain regions., This study was supported by the COST Action CLIMO (Climate-Smart Forestry in Mountain Regions – CA15226) financially supported by the EU Framework Programme for Research and Innovation HORIZON 2020. This publication is also part of a project that has received funding from the European Union’s HORIZON 2020 research and innovation programme under the Marie Skłodowska-Curie grant agreement No 778322 (CARE4C)., 10 Pág.

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.

U radu su korišteni podaci izmjere 377 modelnih stabala smreke koja su mjerena u oborenom stanju na širem području unutar državnih raznodobnih sastojina u Kantonu 10 (Hercegbosanski Kanton). Za određivanje volumena krupnog drveta stabala primijenjena je metoda sekcioniranja sa sekcijama nejednakih apsolutnih dužina (najčešće od 1 – 2 m). Za izravnanje veličina volumena krupnog drveta od prsnog promjera i visine stabala primijenjena je metoda višestruke regresijske analize. Za procjenu parametara korištenih funkcija, testiranje značajnosti njihovih razlika te provođenje raznih transformacija, kao softversko rješenje korišteni su StatGraphics Centurion XVII. i Statistica 8.0. U cilju izbora „najboljeg“ modela za procjenu volumena krupnog drveta testiran je veći broj poznatih dendrometrijskih dvoparametarskih volumnih funkcija. Kvaliteta izjednačenja i prikladnost testiranih modela ocjenjivani su na bazi utvrđenih veličina osnovnih statističkih pokazatelja za karakteriziranje jačine korelacijskih veza. Najbolje ocjene parametara pokazao je model V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h uz utvrđeni koeficijent determinacije: R2 = 0,99 i veličinu standardne greške regresije Sey=0,24 m3. Testirajući značajnost razlika između stvarnih volumena stabala iz uzorka i volumena tih istih stabala utvrđenih primjenom odabranog regresijskog modela, utvrđen je prosječni postotak odstupanja od 0,44%. To znači da su u prosjeku za 0,44% niži volumeni u odnosu na stvarne volumene na uzorku od 377 stabala smreke, što ukazuje da je ovaj regresijski model upotrebljiv za primjenu u praktičnom radu, jer je taj prosječni postotak manji od 1%., For assessment of growing stock in B&H forestry praxis as scientific baseline we are using volume tables and tariffs (Drinići dr. 1990). Having in mind the fact that these are constructed based on volume coefficients of the trees taken from German tree volume tables, which originate from single-age assortments, it is justified to suspect that by applying these tables one will get certain differences in quantity of large wood mass related to the actual status of those volumes. It is known that trees of the same tree species coming from single-age assortments are more full-bodied because they have larger volume coefficients compared to the trees of the same species from variable aged and selection forest assortments. That is why the objective of this research is to find “the best” regression model for levelling of volume of large wood of spruce, as dependent variable depending on diameter at breast height and tree height, as independent variables. To achieve this objective we have selected 377 model trees of spruce that were measured in felled condition on wider area of state owned variable aged assortments in Canton 10 (Livno Canton). To determine volume of large wood of trees we applied section method with sections of uneven absolute lengths (most often from 1 – 2 m). For levelling of volumes of large wood depending on diameter at breast height and tree height we applied method of multi-regression analysis. Quality of levelling and appropriateness of tested models was evaluated on the basis of determined values of basic statistical indicators for characterisation of the strength of correlation connections. The best values of the parameters showed model: V7=a0+a1d1,3+a2h+a3d1,3h+a4d1,32+a5 d1,32h with determined determination coefficient: R2 = 0,99 and size of standard regression error: Sey=0,245 m3. By testing significance of differences between actual/real tree volumes from the sample and volume of those trees determined by application of selected regression model by using t-test of pairs, no statistically significant differences were recorded. Average percentage of deviation was -0.44%. That means that in average we get 0.44% lower volumes comparing to the actual volumes in the sample of 377 spruce trees which shows that this regression model is usable for application in practice, because that average percentage is less than 1%. Statistically significant differences were recorded between volumes of trees of selected regression model and volume tables and models of other authors (Stojanović i dr. 1978; Banković i dr. 2003; Špiranec, 1976.). Those deviations vary in the range from 2.53% up to 22.7%. The largest deviations were determined exactly in model that is used in B&H (Stojanović i dr. 1978) and are in amount of 22.7% while the lower deviations were determined for volumes estimated by using model created for spruce trees from Sub-Alpine belt for area of Kopaonik (Banković i dr. 2003) and those amount to 2.53%.

In Europe, mixed mountain forests, primarily comprised of Norway spruce (Picea abies (L.) Karst.), silver fir (Abies alba Mill.), and European beech (Fagus sylvatica L.), cover about 10 × 106 ha at elevations between ∼600 and 1600 m a.s.l. These forests provide invaluable ecosystem services. However, the growth of these forests and the competition among their main species are expected to be strongly affected by climate warming. In this study, we analyzed the growth development of spruce, fir, and beech in moist mixed mountain forests in Europe over the last 300 years. Based on tree-ring analyses on long-term observational plots, we found for all three species (i) a nondecelerating, linear diameter growth trend spanning more than 300 years; (ii) increased growth levels and trends, the latter being particularly pronounced for fir and beech; and (iii) an elevation-dependent change of fir and beech growth. Whereas in the past, the growth was highest at lower elevations, today’s growth is superior at higher elevations. This spatiotemporal pattern indicates significant changes in the growth and interspecific competition at the expense of spruce in mixed mountain forests. We discuss possible causes, consequences, and silvicultural implications of these distinct growth changes in mixed mountain forests.

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.

Mixed mountain forests of European beech (Fagus sylvatica L.), Norway spruce (Picea abies (L.) Karst), and silver fir (Abies alba Mill.) cover a total area of more than 10 million hectares in Europe. Due to altitudinal zoning, these forests are particularly vulnerable to climate change. However, as little is known about the long-term development of the productivity and the adaptation and mitigation potential of these forest systems in Europe, reliable information on productivity is required for sustainable forest management. Using generalized additive mixed models this study investigated 60 long-term experimental plots and provides information about the productivity of mixed mountain forests across a variety of European mountain areas in a standardized way for the first time. The average periodic annual volume increment (PAI) of these forests amounts to 9.3 m3ha−1y−1. Despite a significant increase in annual mean temperature the PAI has not changed significantly over the last 30 years. However, at the species level, we found significant changes in the growth dynamics. While beech had a PAI of 8.2 m3ha−1y−1 over the entire period (1980–2010), the PAI of spruce dropped significantly from 14.2 to 10.8 m3ha−1y−1, and the PAI of fir rose significantly from 7.2 to 11.3 m3ha−1y−1. Consequently, we observed stable stand volume increments in relation to climate change.

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.

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.

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).

UDK 630*5:582.4(497.6) Dugo prisutan problem u šumarstvu BiH je velika zastupljenost slabo produktivnih, uglavnom nekvalitetnih izdanačkih šuma ili neobraslih površina. Na oko 50% šumskih površina u BiH proizvodni potencijal staništa ne koristi se optimalno, odnosno ne proizvodi se maksimalna količina kvalitetnog drveta. Jedna od primjenjivanih mjera za prevazilaženje ovog problema je unošenje i podizanje zasada autohtonih i alohtonih vrsta drveća koje se odlikuju brzim rastom i kvalitetnim drvetom. Podignuti su brojni zasadi smrče (Picea abies Karst.), bijelog (Pinus sylvestris L.) i crnog bora (Pinus nigra Arn.), te u manjem broju zelene duglazije (Pseudotsuga mensiesii Franco.), evropskog (Larix europaea L.) i japanskog ariša (Larix leptolepis Gord.) i američkog borovca (Pinus strobus L.). Postignuti rezultati su zbog nedostatka iskustva bili različiti. Provedena su istraživanja proizvodnih i strukturnih karakteristika zasada smrče, bijelog i crnog bora u BiH, dok su za alohtone vrste drveća istraživanja provedena samo parcijalno. Prilog tom istraživanju je i istraživanje predstavljeno u ovom radu. Cilj ovog rada je analiza i ocjena proizvodnosti šest vrsta četinara (3 autohtone i 3 alohtone) u komparativnom ogledu na području Gostovićke rijeke.

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.

UDK 630*54:582.475(497.6) Značajne šumovite nepokrivene površine u Bosni i Hercegovini obrađivale su se sastojine smreke, bijelog i crnog bora. U posljednje vrijeme nije uspostavljen znanstveni pristup gospodarenju, pa su u upotrebi inozemne tablice prinosa (Shober, 1975.; Frauendorfer, 1954.). Upotreba tih tablica nije ispravna zbog različitih karakteristika štanda i mnogih drugih čimbenika. Radi utvrđivanja poreznih osnova za plansko i racionalno gospodarenje ovim sastojinama provedeno je ispitivanje njihovih razvijenih, strukturnih i proizvodnih karakteristika. Prvi zadatak u ovom istraživanju, nakon procjene zemaljskih podataka, je definiranje rasporeda klasa mjesta. Cilj ovog rada je razviti dispoziciju krivulja prosječno visinskih klasa lokaliteta, odnosno relativnih visinskih klasa lokaliteta jednodobnih sastojina crnog bora na karbonatnoj podlozi u Bosni

Centro de Investigación Forestal (CIFOR), Recent studies show that several tree species are spreading to higher latitudes and elevations due to climate change. European beech, presently dominating from the colline to the subalpine vegetation belt, is already present in upper montane subalpine forests and has a high potential to further advance to higher elevations in European mountain forests, where the temperature is predicted to further increase in the near future. Although essential for adaptive silviculture, it remains unknown whether the upward shift of beech could be assisted when it is mixed with Norway spruce or silver fir compared with mono-specific stands, as the species interactions under such conditions are hardly known. In this study, we posed the general hypotheses that the growth depending on age of European beech in mountain forests was similar in mono-specific and mixed-species stands and remained stable over time and space in the last two centuries. The scrutiny of these hypotheses was based on increment coring of 1240 dominant beech trees in 45 plots in mono-specific stands of beech and in 46 mixed mountain forests. We found that (i) on average, mean tree diameter increased linearly with age. The age trend was linear in both forest types, but the slope of the age–growth relationship was higher in mono-specific than in mixed mountain forests. (ii) Beech growth in mono-specific stands was stronger reduced with increasing elevation than that in mixed-species stands. (iii) Beech growth in mono-specific stands was on average higher than beech growth in mixed stands. However, at elevations > 1200 m, growth of beech in mixed stands was higher than that in mono-specific stands. Differences in the growth patterns among elevation zones are less pronounced now than in the past, in both mono-specific and mixed stands. As the higher and longer persisting growth rates extend the flexibility of suitable ages or size for tree harvest and removal, the longer-lasting growth may be of special relevance for multi-aged silviculture concepts. On top of their function for structure and habitat improvement, the remaining old trees may grow more in mass and value than assumed so far., Open Access funding enabled and organized by Projekt DEAL.The authors would like to acknowledge networking support by the COST (European Cooperation in Science and Technology) Action CLIMO (Climate-Smart Forestry in Mountain Regions—CA15226) financially supported by the EU Framework Programme for Research and Innovation HORIZON 2020. This publication is part of a project that has received funding from the European Union’s HORIZON 2020 research and innovation programme under the Marie Skłodowska-Curie Grant Agreement No 778322. Thanks are also due to the European Union for funding the project ‘Mixed species forest management. Lowering risk, increasing resilience (REFORM)’ (# 2816ERA02S under the framework of Sumforest ERA-Net). Further, we would like to thank the Bayerische Staatsforsten (BaySF) for providing the observational plots and to the Bavarian State Ministry of Food, Agriculture, and Forestry for permanent support of the Project W 07 ‘Long-term experimental plots for forest growth and yield research’ (#7831-26625-2017). We also thank the Forest Research Institute, ERTI Sárvár, Hungary, for assistance and for providing observational plots. Furthermore, our work was partially supported by the SRDA via Project No. APVV-16-0325 and APVV-15-0265, the Ministry of Science and Higher Education of the Republic of Poland, the Project “EVA4.0” No. CZ.02.1.01/0.0/0.0/16_019/0000803 funded by OP RDE and the Project J4-1765 funded by the Slovenian Research Agency and also by the Bulgarian National Science Fund (BNSF) and the Project No. DCOST 01/3/19.10.2018., 19 Pág.