Karakteristike prorede u zasadu topole klona B-229 (Populus deltoides Bartr. Ex Marsh.) u Donjem Sremu

Abstract

U zasadu topole klona B-229 (Populus deltoides Bartr. ex Marsh.), na zemljištu tipu fluvisol, varijetet dvoslojno sa fosilnim zemljištem na lesoaluvijumu reke Save, koji je osnovan pri razmaku sadnje 5×5 m, odnosno 400 stabalaha-1, nakon 8 godina od osnivanja primenjena je proreda selektivnog karaktera. U okviru kvadratnog rasporeda stabala izdvojena su fenotipski bolje formirana stabla u broju koji definiše prosečni razmak stabala od 7×7 m, odnosno 204 stablaha-1, i uklonjeni su im najznačajniji konkurenti. TakoĐe su uklonjena i neperspektivna stabla. Proredom, koja je imala karakter niske prorede, uklonjeno je 169 stabala po hektaru (45,3%), temeljnica je smanjena za 6,56 m2·ha-1 (37,2%), a zapremina za 57,27 m3·ha-1 (36,3%). Značajno razdvajanje kolektiva doznačenih stabala i kolektiva preostalih stabala po elementima rasta stabala i zasada, kao i visinske i debljinske strukture ukazuje da se proreda značajno razlikovala od tipične šematske prorede. Vrednost potencijalne strukture sortimenata prorednog etata od 18,52 m3·ha-1 trupca za rezanje II klase i 26,53 m3ha-1 celuloznog drveta omogućava pozitivan bilans u poreĐenju sa direktnim troškovima seče i privlačenja prorednog etata i većih troškova pošumljavanja pri većoj gustini (5×5 m) u poređenju sa razmakom 7×7 m, što ukazuje na opravdanost prorede sa ekonomskog aspekta.

A selective thinning was applied eight years after development of a poplar clone B-229 (Populus deltoides Bartr. ex Marsh.) stand established on fluvisol, var. double-layer with fossil soil on loess-alluvium of the Sava river, with the planting distance of 5×5 m, i.e. 400 trees·ha-1. Within the square distribution of trees the phenotipically distinct trees were separated into a number defining an average distance between the trees of 7×7 m, i.e. 204 treesha-1, and their most significant competitors were removed. Non-perspective trees were also removed. By application of low thinning technique some 169 trees per hectare were removed (45,3%), basal area was reduced by 6,56 m2ha-1 (37,2%), and the volume by 57,27 m3·ha-1 (36,3%). Significant separation of the group of assigned trees, and the group of the remaining trees according to the elements of tree and stand growth, as well as the height and diameter structures revealed that the thinning significantly differed from the schematic diagram of typical thinning. The value of the potential assortment structure of allowable cut in the thinning of 18,52 m3·ha-1 logs intended for cutting, class II, and 26,53 m3·ha-1 of cellulose wood provided positive balance in comparison to the direct felling costs, and transport of the allowable cut in the thinning, and higher dense (5×5 m) a forestation costs compared to the planting distance of 7×7 m, indicating that the thinning was justified from the economic aspects.