Structure and productivity of mixed spruce and fir forests on Mt. Kopaonik

The subject of this research are mixed forests of spruce and fir in the area of NP Kopaonik, which belong to the community of spruce and fir - Abieti-Piceetum abietis Mišić et Popović, 1978. The basis for the study of the structural development and production potential of these forests are data from 12 sample plots, with the average size of 0.18 ha. In terms of coenoecological affiliation all the sample plots belong to the group of ecological units – forests of spruce and fir (Abieti-Piceetum abietis, Mišić et Popović, 1978) on acid brown and brown podzolic soils, which are differentiated into 5 ecological units: Abieti-Piceetum abietis oxalidetosum on brown podzolic soil, Abieti-Piceetum abietis oxalidetosum on acid brown soil, Abieti-Piceetum abietis vac- cinietosum on brown podzolic soil, Abieti-Piceetum abietis typicum on brown podzolic soil and Abieti-Piceetum abietis Dr.ymetosum on brown pozolic soil. In structural terms, these forests are characterized by very diverse structural forms, ranging from the structure of even-aged stands to typical multi-storey, unevenaged-aged stands. The form of cumulative curves of tree distribution is in most cases determined by spruce as the domi- nant species. At the same time, thin and medium-thick trees dominate, while the presence of stems with large dimensions is minimal. The average volume of these forestse is 777 m3 ·ha–1 , with a mixture ratio of 0.7: 0.3 in favor of spruce. The average value of the current volume increment is 14 m3 ·ha–1 , with a 68% share of spruce and 32% of fir. The percentage of increment ranges from 1.6% to 2.5% in all sample plots and is somewhat higher for fir. The site potential, stand characteristics and relations among the tree species have resulted in structural complexity, high productivity and ecological stability of these forests. Therefore, future forest man- agement should avoid radical measures and procedures that would violate the established relationships and dynamic processes. Key