STAND STRUCTURE, DEAD WOOD AND FLORISTIC COMPOSITION OF A PRISTINE FOREST STAND OF BEECH AND FIR COMPARED TO A MANAGED FOREST IN THE DINARIC MOUNTAIN BJELAŠNICA

UDK: 630*228(234.422 Bjelašnica)(253) This paper presents the results of a comparative analysis of the structural and vegetation characteristics of "Ravna vala" pristine (virgin) forest and the managed forest of beech and fir (with spruce). Pristine forest "Ravna vala" is located in the central part of Bosnia and Herzegovina, about 20 km southwest of Sarajevo on Bjelašnica Mountain, at an altitude from 1280 to 1450 m. The managed forest of beech and fir with spruce, which was used for comparison, borders "Ravna vala" and has the same habitat conditions: climate, orography and land, and the similar structural characteristics and composition of tree species as the pristine forest. Beech and fir communities (Abieti-Fagetum illyricum Treg. 1957) dominate but spruce can also be found in the area of ​​research. Noble hardwoods such as sycamore and elm are found both individually or in small groups in depressions in deeper soils. Both the pristine forest and the managed forest show the selective diameter structure. However, the great differences between the pristine forest and the managed forest are final diameter classes. The thickest tree in the pristine forest has the breast diameter of 145 cm, while the diameter of the thickest tree in the industrial forest is 70 cm. The volume of the stands is 770 m3/ha in the pristine forest and it is two times larger than in the managed forest. The volume of dead wood in the pristine forest is 170 m3/ha and it is five times larger than in the managed forest. While stumps and thicker branches are the most common in the stock of dead trees in the managed forest, the most common in the stock of dead wood in the pristine forest are tall stumps as well as lying and standing dead trees. Floristic researches have shown that selective management does not reflect negatively on floristic diversity, but ground vegetation is richer in species in the managed forest. Shannon's diversity index and evenness index of vascular flora have higher values ​​in the managed forest. Unlike floristic diversity, the stand diversity index of Jähne & Dohrenbusch (1997) shows higher values ​​in the pristine forest than in the managed forest.