718 KB50 KB193820262024Klopčič, MatijaKonjar, Matevžštevilka:4/5letnik:82str. 167-183ISSN:0017-2723COBISSID_HOST:208272643URN:URN:NBN:SI:doc-QKJUSR92enslZveza gozdarskih društev SlovenijeGozdarski vestnikAlpeAlpsbark beetlenaravne motnjenatural disturbancespodlubnikivetrolomwind breakNaravne motnje na Bovškem – analiza vpliva naravnih motenj in vzrokov za njihovo pojavljanje| Natural disturbances in Bovec region – analysis of the impact and factors for the occurrence of natural disturbance|The research analysed the structure of harvested timber in the Bovec region in the period 1995–2020 with an emphasis on sanitary felling due to windthrow and bark beetles outbreaks. Research determined the main influencing factors affecting the probability of windthrow and bark beetle outbreak. From Slovenia Forest Service we acquired the data presenting the amount and structure of felling performed in research area in the period 1995–2020. He also gathered stand-, site- and climate-related data from 26 locations of windthrow with a known time of occurrence and 26 forest sections damaged by bark beetles outbreaks. Data was analysed using descriptive statistics, bivariate analyses and binary logistic regression. In the research area, we detected significant increase in the amount of sanitary felling after 2018. The main causes of sanitary felling were windthrow and bark beetle outbreaks. Binary logistic regression highlighted stoniness, the presence of past disturbance and undulating relief as key factors for the occurrence of windthrow. Bivariate analyses showed that windthrow mainly occurred on moderate to steep ridges with southern exposure, in mature stands with a high growing stock, dense or partly-opened canopy cover, and higher proportion of gaps containing regeneration stages. Analysis also proved the impact of strong south-western winds. For the occurrence of bark beetle outbreaks, the binary logistic regression highlighted growing stock and share of conifers as key influential factors. Bivariate analyses indicated that bark beetle outbreaks occurred more frequently in areas with undulating relief, south-eastern exposure, higher proportion of regenerative stages and stands under regeneration, as well as lower proportion of pole stands. We also analysed the growing trend of sanitary felling after the end of the analysed period 1995-2020V raziskavi smo analizirali strukturo poseka na Bovškem v obdobju 1995–2020 s poudarkom na sanitarnem poseku zaradi vetra in podlubnikov ter poskušali poiskati glavne dejavnike, ki vplivajo na verjetnost pojavljanja vetrolomov in namnožitve podlubnikov. Pridobili smo podatke o količini in strukturi poseka za raziskovalno območje v obdobju 1995–2020 in podatke o šestindvajsetih lokacijah vetrolomov z znanim časom nastanka ter šestindvajsetih odsekih, poškodovanih zaradi podlubnikov. Podatke smo analizirali s pomočjo metod opisne statistike, bivariatne analize in binarne logistične regresije. V raziskovalnem območju smo zaznali izrazito povečanje sanitarnega poseka po letu 2018. Glavna vzroka sanitarnih sečenj sta bila veter in podlubniki. Binarna logistična regresija je kot ključne dejavnike za pojav vetrolomov izpostavila kamnitost in prisotnost minulih motenj ter valovitega reliefa. Bivariatne analize so pokazale tudi, da se vetrolomi pojavljajo predvsem v debeljakih z visoko lesno zalogo, ki rastejo na zmernih do strmih grebenih z južno ekspozicijo, imajo tesen ali vrzelast sklep in večji delež pomlajenih vrzeli. Binarna regresija je izpostavila tudi vpliv močnih jugozahodnih vetrov, ki prinašajo obilne padavine. Za pojav podlubnikov je binarna logistična regresija kot ključne dejavnike izpostavila količino lesne zaloge in delež iglavcev. Bivariatne analize so pokazale tudi, da se podlubniki pogosteje pojavljajo v odsekih z valovitim reliefom in jugovzhodno ekspozicijo, večjim deležem mladovij in sestojev v obnovi ter manjšim deležem drogovnjakov. Analizirali smo tudi trend večanja sanitarnega poseka po koncu proučevanega obdobja 1995–2020TEXTznanstveno časopisjejournalsSlovenian National E-content AggregatorNational and University Library of SloveniaZveza gozdarskih društev Slovenije