Načini sanacij posledic ujm in uspešnost obnove sestojev na rastiščih bukovih gozdov : doktorska disertacija

Fidej, Gal (author), Diaci, Jurij (mentor)

Doktorska disertacija je sestavljena iz treh sklopov. V prvem sklopu smo proučili vplive tehnične sanacije (posek in spravilo) na obnovo vegetacije po ujmah manjših do srednjih jakosti v mešanih, pretežno bukovih sestojih na osmih raziskovalnih objektih po Sloveniji, kjer je bila na delu površine opravljena tehnična sanacija, medtem ko preostali del ni bil saniran. Raziskava je pokazala, da med načinoma dela ni bilo bistvenih razlik v gostotah, višinski strukturi in hitrosti rasti mladja. Majhne razlike nakazujejo, da je na predelih brez tehnične sanacije nekoliko več bolj razvitega oz. višjega mladja, ki se je verjetno ohranilo iz prejšnjega sestoja, medtem ko je na saniranih predelih nekoliko več manj razvitega oz. nižjega mladja svetloljubnih drevesnih vrst, ki je lahko vraščalo zaradi odstranjenih drevesnih ostankov in majhnih poškodb tal pri spravilu. Tehnična sanacija po ujmah majhnih do srednjih jakosti v mešanih, pretežno bukovih sestojih ni imela negativnih vplivov na obnovo vegetacije. V drugem sklopu smo proučili razlike med naravno in umetno obnovo na treh raziskovalnih območjih, ki jih je leta 2008 prizadel vetrolom. Osnovali smo ploskve na mestih naravne obnove, kjer smo popisovali dominantne osebke naravnega mladja, na mestih umetne obnove pa sadike. Znotraj obeh tipov ploskev smo postavili ploskvice za analizo vegetacije, kjer smo popisali pokrovnost zeliščne vegetacije in gostote naravnega mladja. Rezultati kažejo, da je bila naravna obnova različno uspešna. Na območju Trnovski gozd je bila pomanjkljiva zaradi zaostrenih ekoloških razmer, na zgornjem delu Črnivca zaradi goste travne ruše vijugave masnice, na Bohorju pa je bila uspešna. Gostote naravnega pomladka so bile na ploskvah z umetno obnovo od tri- do štirikrat nižje kot na ploskvah naravne obnove, kar je verjetno posledica obžetev sadik, s čimer se verjetno odstrani samoniklo mladje. V tretjem sklopu smo proučili dolgotrajno drugotno sukcesijo po požaru na Mozirski Požganiji. Leta 2013 smo ponovili meritve stalnih vzorčnih ploskev, ki so bile prvič premerjene leta 1981. Izsledki kažejo, da so na preživetje dreves ključno vplivale drevesna vrsta, višina, drevesna plast in globina krošnje. Smreka je imela najvišjo stopnjo preživetja, sledijo breza, trepetlika in iva. Visok začetni delež smreke in povečevanje njenega deleža kažeta na pionirske lastnosti smreke, ki v začetnem obdobju brez težav tekmuje z drugimi pionirji, kasneje pa se uveljavi kot poznosukcesijska vrsta, ko se pionirji že umikajo iz sestojev.

• Language: Slovenian
• Keywords: bukova rastišča, ujme, vetrolom, sanacija ujm, pomlajevanje, naravna obnova, umetna obnova, saditev, uspeh obnove, sekundarna sukcesija, požari, gozdni požari, Črnivec, Bohor, Trnovski gozd, disertacije
• Work type: Doctoral dissertation
• Typology: 2.08 - Doctoral Dissertation
• Organization: BF - Biotechnical Faculty
• Place of publishing: Ljubljana
• Publisher: [G. Fidej]
• Year: 2016
• Number of pages: XI, 116 str.
• PID: 20.500.12556/RUL-115371
• UDC: 630*231:630*42(043.3)=163.6
• URN: URN:NBN:SI:doc-YYDGKGVA
• COBISS.SI-ID: 872567
• Publication date in RUL: 24.04.2020

Secondary language

• Language: English
• Title: Post-disturbance treatments and stand restoration success in beech forest sites

Abstract

This dissertation comprises three studies. In the first study we examined the influence of salvage logging on forest regeneration following small to medium-scale moderate severity disturbances in eight mixed beech (Fagus sylvatica L.) dominated forest stands in Slovenia where part of the disturbed area was salvaged and the adjacent part was not salvaged. Results show that there were no significant differences in terms of densities, height structure and regeneration growth between treatments. Minor differences indicate that the non-salvaged sites tended to have a slightly more well-developed (taller) regeneration layer that remained from the previous stand and was not damaged during harvesting, while salvaged sites had a larger proportion of shade intolerant tree species due to the removal of damaged timber, which created minor soil disturbances and space for easier recruitment of regeneration. The results suggest that salvage logging following small-scale intermediate severity disturbances may not hinder forest recovery in mixed beech dominated forests. In the second study we analyzed the differences between planted and natural regeneration on three research areas disturbed by storms in 2008. We established sampling plots of natural regeneration where the dominant trees of the natural regeneration were measured and sampling plots with artificial regeneration where all planted seedlings were measured. Within both plot types, smaller vegetation subplots were established where the cover of each plant species was estimated and natural regeneration was counted. Results show that the success of the natural regeneration varied between research areas and study sites. Natural regeneration densities in Trnovski gozd were not sufficient due to the more extreme ecological conditions, while at the Bohor area the densities were high. On the upper slope of Črnivec, the natural regeneration was inhibited by thick grass of Deschampsia flexuosa (L.) Trin. Average densities of natural regeneration were 3-4 times higher on the plots with natural regeneration, which may be due to collateral damage to natural regeneration during ground vegetation removal on planted sites. In the third part of the dissertation, we studied secondary succession after forest fire at Mozirska Požganija. In 2013 we remeasured the plots established and inventoried in 1981. Results indicate that tree species, height, layer and crown depth positively influenced tree survival. Spruce showed the highest survival probability, followed by Betula pendula (Roth.), Populus tremula (L.) and Salix caprea (L.). The high initial proportion of spruce and its increasing share indicates the pioneer characteristics of a species that can easily compete with pioneers and later establish as a late successional species after pioneers retreat from the stands.

• Keywords: beech sites, disturbances, windthrow, forest restoration, natural regeneration, artificial regeneration, planting, regeneration success, secundary succession, fires, forest fires, Črnivec, Bohor, Trnovski gozd