This paper compares the forest structure, regeneration and distribution of dead wood in a virgin forest remnant and a closeto-nature managed beech -conifer mixture situated on Grmeč Mountain in Western Bosnia. The investigations were carried out in a 1 ha permanent sample plot and 35 circular plots (20 m radius) in the virgin forest and in 17 circular plots (25 m radius) in managed forests. The number of trees in the managed forest was significantly ( p ¼ 0.05) higher than that in virgin forest and the distribution of the number of trees per diameter classes had a decreasing trend, but with a different shape in the virgin forest compared to the managed stands. In the lower diameter classes, the stock volume recorded in virgin forest was half of that in the managed forest, whilst for higher diameter classes the cumulated volume of the growing stock was almost double in virgin forest. The young crops had a significantly lower presence in the virgin forest and a larger volume of dead wood was identified in the virgin forest than in managed stands. The study results are important in assessing the consequences of close-to-nature management on the forest structure and regeneration when compared to the condition in virgin forests.
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.
Mechanisation used in forest utilisation has an impact on the occurrence of damage in stand and on forest land. The research in this work had the objective of determining damage on fir trees and other tree species during felling and processing of trees and their skidding using the forest cable-skidder. The research wasconducted in mixed beech and fir forests in the area of FMA “Glamočko”, M.U. “Hrbinje-Kujača”. The following data were gathered on damaged trees: tree type, breast height diameter, economic importance of the tree, amount of damage, location of damage, cause of damage, types of damage. Damage was recorded on a total of 305 trees, 133 trees of silver fir (Abies alba), 130 trees of European beech (Fagus sylvatica), 33 trees of European spruce (Picea abies), 8 trees of rowan/mountain-ash (Sorbusaucuparia) and one tree of sycamore (Acer pseudoplatanus). The overall damage intensity was 18.7%, but together with the old damages, the overall number of ‘wounds’ is 496. According to this, when the old damage isalso considered, then the intensity of damage amounts to 30.6%. The largest amount of damage is in the diameter sub-class ranging from 10 to 14.99 cm. According to the cause of damage, the largest amount of damage occurred during the wood extraction phase (217 trees), while during the felling phase, 88 trees or 29% were damaged. Since the wood extraction phase is divided into the winching and skidding phases, the total number of damaged trees during the winching phase amounted to 157 or 52%, while during the skidding phase, the number of damaged trees was 60 or 19%. To reduce damage to the trees during following operations in forest utilisation, it is necessary to perform more frequent training of all employees working on forest utilisation, to increase controls in execution of operations during forest utilisation, modernise machines used during forest exploitation, and in quality manner open compartments with forest road infrastructure.
UDK: 630*228(234.422 Bjelašnica)(253) This work researches structural composition, texture and diversity of development phases of virgin forest „Ravna vala“ on Bjelašnica. Virgin forest „Ravna vala“ is located in central part of Bosnia and Herzegovina, about 20 km south west from Sarajevo on mountain Bjelašnica, on altitude of 1280 to 1450 m. First time it was described in 1978. Within it we have positioned permanent plot of the square shape in size of 1 ha. Research was conducted on permanent plot in three time series: in years 1978, 1988 and 2008, and on 46 temporary systematically positioned circular plots in diameter of 12.6 meters, where each represents as per 1 ha of virgin forest area. In virgin forest we have registered 689 trees per hectare and wood supply mass of 701 m3/ha. Through analysis of dynamics of growth of specific species trees, it is visible that beech suppresses fir, i.e. there is a shift in main species in virgin forest, therefore, in the last 30 years number of beech trees has tripled in the lower diameter classes. Virgin forest has mostly present optimum phase and evenness phase, and rejuvenation phase. Texture diversity is expressed through Shannon index in value of 1.69, and evenness index has the value of 0.86.
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 12,5 cm) 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.
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.
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