The first ecological research in the Illyrian phytogeographic area, located on the Balkan peninsula in south-eastern Europe, dates back to the early 20th century. Traditionally, the Illyrian phytogeographic area includes Bosnia and Herzegovina, Montenegro, Croatia and parts of Slovenia. Due to climate change, more available data and new measurement techniques, the Illyrian phytogeographic area may have shifted northwards to the southern Alps and parts of Austria. In this study we have analysed climate as an important ecological variable for delineating the Illyrian phytogeographic area using precipitation and air temperature from 75 climatological stations in Bosnia and Herzegovina, Croatia, Slovenia and Austria (Carinthia). Our statistical analysis suggests, that there are significant differences in the analysed climate parameters across the countries, suggesting that sub-sections may already exist within the extent of the Illyrian phytogeographic area.

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.

UDK: 630*232:582.475(497.6) Provenance experiments with forest trees provide valuable information about the growth and adaptability of population, often transferred from remote geographical regions and various climate conditions. This study researches the growth of nine provenances of silver fir from the area of its natural distribution in Bosnia and Herzegovina. The experiment was established in the year 1991 in the form of a random block system with 5 repetitions. For planting, we used five-year-old seedlings (2/3), and planting spacing was 2x2 m. Each Silver fir provenance was included with 320 plants. Measurement results in the 28th year of age show the existence of variations between silver fir provenances in characteristics; mean height, mean diameter and average tree volume. Silver fir provenance from Bosanski Petrovac showed the best results. The mean height of this Silver fir provenance at the age of 28 was 9.1 m, while the mean diameter was 11.9 cm. Provenances that show the lowest growth (8.1 m) were from Pale, Olovo-Klis and Konjic. Silver fir provenance from Konjic has the lowest mean diameter (10.7 cm). In all provenances, we have had a culmination of height increment in age between 20 and 25 years. Variation between tested silver fir provenances for examined characteristic “mean height” was larger (four groups of population) compared to examined characteristic “mean diameter” (two groups of population). Volume of mean tree (0.062m3) and assortment (111.33 m3/ha) in Bosanski Petrovac provenance was larger than spreadsheet values for the first yield class for Central Europe conditions. The trial shows that silver fir in Bosnia and Herzegovina is variable on the local level due to specific micro-habitual conditions in which it grows.

Current tables of wood assortments for the most important tree species in B&H were made almost 50 years ago. There is an indication that real forest wood assortments are different than the one derived from assortment tables in-use, both in terms of quality and dimensions. In the meantime, from the creation of the existing tables until today, the standards of production of forest wood assortments have changed, so that the fact of inaccuracy of the existing assortment tables is unquestionable. This continually creates a variety of problems in the ongoing operations of forestry companies. The main aim of this paper is to create wood assortment tables whose assortment of wood products will correlate with the current market conditions. The research was conducted in the area of the Canton 10 in FB&H.  A sample of 393 spruce trees was used as a database to produce this paper. The bucking of the sample trees was carried out in accordance with the valid norms and customer requirements with regards to the dimensions of forest wood products. Data processing was performed using methods of simple and multiple regressions, variance analysis as well as their combinations by the Generalized Linear Models method. Independent factors were breast diameter (DBH), technical quality class and the height of the trees. The share of wood assortments was determined through 10 different mathematical models, and it was found that all independent variables had a statistically significant influence on the dependent variables- volume of particular assortments or group of assortments. The share of logs is growing rapidly with the increase of tree diameter and decreases with decreasing of their technical quality. The influence of tree height primarily correlated with tree volume increase. Trees having better assortment quality, have tree heights higher than average for the same diameter class. The results of the research are presented in the form of tables as percentage share of wood assortment classes.  The obtained results can be used as wood assortment tables in the research area.

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%.

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.

Background and Purpose: Coppice forests have a particular socio-economic and ecological role in forestry and environmental management. Their production sustainability and spatial stability become imperative for forestry sector as well as for local and global communities. Recently, integrated forest inventory and remotely sensed data analysed with non-parametrical statistical methods have enabled more detailed insight into forest structural characteristics. The aim of this research was to estimate forest attributes of beech coppice forest stands in the Sarajevo Canton through the integration of inventory and Sentinel S2A satellite data using machine learning methods. Materials and Methods: Basal area, mean stand diameter, growing stock and total volume data were determined from the forest inventory designed for represented stands of coppice forests. Spectral data were collected from bands of Sentinel S2A satellite image, vegetation indices (difference, normalized difference and ratio vegetation index) and biophysical variables (fraction of absorbed photosynthetically active radiation, leaf area index, fraction of vegetation cover, chlorophyll content in the leaf and canopy water content). Machine learning rule-based M5 model tree (M5P) and random forest (RF) methods were used for forest attribute estimation. Predictor subset selection was based on wrapping assuming M5P and RF learning schemes. Models were developed on training data subsets (402 sample plots) and evaluations were performed on validation data subsets (207 sample plots). Performance of the models was evaluated by the percentage of the root mean squared error over the mean value (rRMSE) and the square of the correlation coefficient between the observed and estimated stand variables. Results and Conclusions: Predictor subset selection resulted in a varied number of predictors for forest attributes and methods with their larger contribution in RF (between 8 and 11). Spectral biophysical variables dominated in subsets. The RF resulted in smaller errors for training sets for all attributes than M5P, while both methods delivered very high errors for validation sets (rRMSE above 50%). The lowest rRMSE of 50% was obtained for stand basal area. The observed variability explained by the M5P and RF models in training subsets was about 30% and 95% respectively, but those values were lower in test subsets (below 12%) but still significant. Differences of the sample and modelled forest attribute means were not significant, while modelled variability for all forest attributes was significantly lower (p<0.01). It seems that additional information is needed to increase prediction accuracy, so stand information (management classes, site class, soil type, canopy closure and others), new sampling strategy and new spectral products could be integrated and examined in further more complex modelling of forest attributes.