Modeling bark thickness of beech (Fagus sylvatica L.)

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.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