Rehabilitation of stands after the storm in the tolmin area

Namen magistrskega dela je bil presoditi uspešnost sanacije na izbranih objektih in pripraviti usmeritve za podporo pri odločanju v prihodnje, saj pričakujemo večjo pogostost in jakost izjemnih vremenskih dogodkov. Na vetrolomni površini, ki je nastala julija 2008 je bilo postavljenih petnajst vzorčnih ploskev (10 m x 10 m) na naravno obnovljenih površinah in petnajst ploskev na umetno obnovljenih površinah, ki so bile posajene s navadno smreko in navadno bukvijo. Na ploskvah so bila izmerjena vsa dominantna drevesca in vse posajene sadike. Opravljen je bil tudi popis gostote in zastiranje naravnega pomladka ter zastiranje grmovne in zeliščne plasti. Gostota naravnega pomladka pri naravni obnovi je bila 8.000 drevesc/ha pri umetni obnovi pa 4.556 drevesc/ha. Zabeleţenih je bilo 8 različnih drevesnih vrst, med katerimi so prevladovale iva, navadna bukev, gorski javor in navadna jelka. Zeliščne in grmovne vrste so v povprečju zastirale 64 %, največje zastiranje je bilo zabeleţeno pri malinjaku. Gostota sadnje je znašala 2.765 sadik/ha. Uspeh sadnje je bil zelo dober, saj je bila mortaliteta tri leta po njej le 7 %. Zastiranje grmovne in zeliščne plasti ter malinjaka je negativno vplivalo na gostoto naravnega mladja. Rezultati raziskave so nakazali, da je bila umetna obnova uspešnejša od naravne obnove, ker pa je bistveno dražja se za umetno obnovo odločamo na najbolj rodovitnih rastiščih, erozijsko ogroženih površinah in tistih z bujno razvito pritalno vegetacijo in na površinah z majhnim številom semenskih dreves.The aim of this thesis was to assess the effectiveness of forest regeneration after the storm on the selected sites in Tolmin region and to offer management guidelines for future decision - making on the matter, considering that a frequency and intensity of extreme weather conditions are expected. In the windthrown areas formed in July 2008 we established 15 sample plots (10 m x 10 m) on the naturally regenerated sites and 15 on the artificially regenerated, which were planted with spruces and beeches. Secondly, we measured all the dominant naturally regenerated seedlings and planted seedlings. In addition, an evaluation of the coverage and density of natural regeneration, shrub and herb layers was carried out. In the naturally regenerated stands the density of young trees accounted for 8.000 trees/ha, where as on the artificially regenerated sites we recorded 4.556 trees/ha. Eight different tree species were identified, the goat willow, common beech, sycamore and fir being the dominant ones. On average herbs and shrubs spread over 64 % of the surface, with in which the raspberry bush represented the highest percentage. The density of planted seedlings accounted for 2.765 specimens/ha. The outcome of planting was highly satisfying, since mortality reached solely 7 % three years after the plantation. Shrub and herb layers along with the raspberry cover had a negative impact on the density of the regeneration. The results of the study indicated that the artificial regeneration was more successful than the natural. Nevertheless, due to its significantly high costs the former is more applicable to the most fertile sites and areas exposed to erosion hazard as well as to those with a luxuriant ground vegetation or a small number of seed trees