Utjecaj na stanište i razvoj šumskih kultura crnoga bora (Pinus nigra J. F. Arnold) na krškom submediteranskom Utjecaj na stanište i razvoj šumskih kultura crnoga bora (Pinus nigra J. F. Arnold) na krškom submediteranskom području | Impact on Site and Development of Black Pine (Pinus nigra J. F. Arnold) Forest Cultures in the Submediterannean Karst Area

The article deals with forest cultures of black pine. Experimental plots were taken in fourteen Forest Offices in the area of Senj Forest Administration, Delnice Forest Administration and Buzet Forest Administration. Climate conditions were shown with climatodiagrams for Senj and Rijeka (Fig. 2 and Fig. 3). This multiple research was aimed at: identifying the site factors that exert the greatest influence on the growth of black pine; analyzing the impact of black pine cultures on the return of climatozonal deciduous vegetation; studying the differences resulting from afforestation with black pine; determining differences between forest cultures in the ameliorative sense. Field plots of 625 m2 were selected, vegetational relevés were made and structural elements of black pine were investigated. Samples of the forest floor (Fig. 1) and the humus-accumulative horizon were analyzed in the laboratory. The obtained data were processed using statistical methods. The research results showed that forest litter and edafic factors have positive impact on amelioration process (Fig. 4, 5, 6, 7). Multivariate analyses revealed that altitude and slope were the two variables that correlated most positively with the floral composition of the vegetation (Fig. 10). Values of the forest floor in terms of quantity were found to have a positive effect on soil degradation and on decreasing erosion processes. Negative impacts were connected with dry periods when the forest floor represents flammable material. Research on the stand structure confirmed the value of black pine stands and not only in the ecological and protective sense but also in the economic sense (Fig. 8, 9). Economic role would be even bigger under conditions of regular silvicultural treatment. Regular thinnings may support successional processes from pine toward decidous vegetation by promoting already established decidous understorey.