Regresioni modeli procenta zapreminskog prirasta u najzastupljenijim sastojinama četinarskih vrsta drveća u Srbiji

Abstract

U ovom radu istraživana je zavisnost između procenta zapreminskog prirasta u sastojinama jele, smrče, crnog i belog bora u Srbiji, s jedne, i broja stabala po hektaru, prečnika srednjeg sastojinskog stabla po preseku, visine srednjeg sastojinskgog stabla po preseku i učešća vrste drveća u smesi, s druge strane. Za svaku vrstu drveća testirana su po 4 regresiona modela, a na osnovu relevantnih statističkih pokazatelja, te tačnosti tablica procenta zapreminskog prirasta, izvršen je definitivni izbor modela za određivanje procenta zapremninskog prirasta za pomenute vrste drveća u Srbiji. Na ovaj način praktična upotreba metoda procenta prirasta za određivanje tekućeg zapreminskog prirasta sastojine u mnogome je olakšana i učinjena još ekonomičnijom u odnosu na druge metode.

Considering the great significance of volume increment in forestry, it is understandable that there are numerous methods of its assessment. However, all these methods have some disadvantages, either the accuracy of the obtained results, too large scope of works of forest inventory (economicity), or the restriction only to stands of certain silvicultural type. To make the method of stand volume increment more economic and simplified, we defined regression models for volume increment percentage assessment in fir, spruce, Austrian pine and Scots pine stands in Serbia. Empirical data were fitted by four regression models for each tree species. The criteria for the final selection of models for the determination of volume increment percentage were the relevant statistic parameters of regression and correlation analysis, and the degree of concordance of "real" and fitted ("table") values of volume increment percentage. The selected models for the above tree species are Fir Spruce Austrian pine Scots pine In the practical work of the assessment of current volume increment in the stand, in regular forest inventories, the method of volume increment percentage should be implemented with correction factors for the fitting of "table" (obtained by this method) values of volume increment and "real" values (obtained by the method of diameter increment), on at least 10 % of the stands of the same or similar stand class (same or similar tree species and stand form). In this way, the costs of forest inventory would be reduced, and the obtained results would range within the limits of the required accuracy.