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V raziskavi smo analizirali strukturo poseka na Bovškem v obdobju 1995–2020 s poudarkom na sanitarnem poseku zaradi vetra, podlubnikov in jesenovega ožiga ter skušali poiskati glavne vplivne dejavnike, ki vplivajo na verjetnost pojavljanja vetrolomov in podlubnikov. Pridobili smo podatke o količini in strukturi poseka za raziskovalno območje v obdobju 1995–2020 ter podatke o 26 lokacijah vetrolomov z znanim časom nastanka in 26 odsekih, poškodovanih s strani 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. Jesenov ožig je bil vzrok za manjši delež poseka. Binarna logistična regresija je kot ključne dejavnike za pojav vetrolomov izpostavila kamnitost ter prisotnost preteklih motenj in valovitega reliefa. Bivariatne analize so pokazale tudi, da se vetrolomi pojavljajo predvsem v debeljakih z visoko lesno zalogo, ki rastejo na zmernih do strmih rebrih z južno ekspozicijo, imajo tesen ali vrzelast sklep in večji delež mladja. Izpostavila je tudi vpliv močnih jugozahodnih vetrov, ki prinašajo obilne padavine. Za pojav podlubnikov je binarna logistična regresija kot ključne dejavnike izpostavila višino 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 mladja in sestojev v obnovi ter nižjim deležem drogovnjakov. The research analyzed the structure of harvested timber in the Bovec region in the period 1995–2020 with an emphasis on sanitary felling due to windthrow, bark beetles and ash dieback. Research also determined the main influencing factors affecting the probability of windthrow and bark beetle outbreaks. Data on the amount and structure of felling were obtained for the research area in the period 1995–2020, as well as data on 26 locations of windthrow with a known time of occurrence and 26 areas damaged by bark beetles. Data were analyzed using descriptive statistics, bivariate analyses and the binary logistic regression. In the research area, significant increase in the amount of sanitary felling after 2018 was detected. The main causes of sanitary felling were windthrow and bark beetle outbreaks, while ash dieback contributed only a smaller share. Binary logistic regression highlighted stoniness, the presence of past disturbances and undulating relief as key factors for the occurrence of windthrow. Bivariate analyses showed that windthrow mainly occurs 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 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 beetles occurred more frequently in areas with undulating relief, south-eastern exposure, higher proportion of regeneration and stands under regeneration, and a lower proportion of pole stands.

Debris flows can transport large amounts of material and therefore present a significant threat to infrastructure and human life. In this research, we used tree-ring width analyses to quantify the response of trees to three debris flow events in NW Slovenia (Javoršček, Srpenica) and W Slovenia (Nikova) for which we know the time of origin. We attempted to date these and similar tree responses in the past and compared the patterns between different tree species. Altogether, we sampled 147 trees across a range of tree species (Fagus sylvatica, Pinus sylvestris, Fraxinus excelsior, Fraxinus ornus, Acer pseudoplatanus, Picea abies, Juglans regia, Acer campestre, Tilia cordata and Ostrya carpinifolia), including reference trees that were outside the debris flow fan. For 91 trees, we constructed tree-ring chronologies and used pointer-year analysis to identify years that had abnormal growth. For the remaining trees (mostly Ostrya carpinifolia, Tilia cordata and Acer pseudoplatanus), we either could not accurately distinguish tree rings or two samples from a single tree showed significantly different growth patterns. The growth patterns of Fagus sylvatica and Picea abies following debris flow events showed a weak response at the Javoršček site and no clear responses at the other two sites. Tree species responded similarly at the same locations. Due to the lack of a clear response pattern, we were not able to reconstruct past debris flows. Drobirski tokovi s sposobnostjo prenašanja večjih količin materiala so nevarni za infrastrukturo in življenje ljudi. Z analizo širine lesnih branik smo v raziskavi poskušali prepoznati odziv dreves na vpliv treh drobirskih tokov v SZ Sloveniji (Srpenica, Javoršček) in Z Sloveniji (Nikova) z znanim časom nastanka, na podlagi spremembe širine branike datirati podobne drobirske tokove v preteklosti in primerjati odzive različnih drevesnih vrst. Na treh lokacijah smo vzorčili skupno 147 dreves različnih drevesnih vrst (Fagus sylvatica, Pinus sylvestris, Fraxinus excelsior, Fraxinus ornus, Acer pseudoplatanus, Picea abies, Juglans regia, Acer campestre, Tilia cordata in Ostrya carpinifolia), vključno z referenčnimi drevesi, ki niso bila izpostavljena delovanju dejavnika. Pri 91 drevesih smo uspešno izdelali drevesne kronologije in z uporabo metode značilnih let ugotovili leta, ki so pri posameznih drevesnih vrstah ter na posameznih lokacijah glede na širno branike kazala zelo različne trende rasti. Pri drugih drevesih vrstah (večinoma Ostrya carpinifolia, Tilia cordata in Acer pseudoplatanus) nam ni uspelo razbrati vseh branik, oz. sta bili po dve zaporedji širin branik istega drevesa različni. V analizi rasti za prvo leto po dogodku smo šibak odziv na vpliv drobirskih tokov zaznali na lokaciji pod Javorščkom, ne pa tudi v Srpenici in Nikovi. Različne drevesne vrste so se na istih lokacijah odzvale podobno. Ker smo zaznali odziv le na eni lokaciji, nismo mogli rekonstruirati drobirskih tokov po posameznih lokacijah v preteklosti.

Drobirski tokovi s sposobnostjo prenašanja večjih količin materiala predstavljajo nevarnost za infrastrukturo in življenja ljudi. Z analizo rasti lesnih branik smo v raziskavi poskušali prepoznati odziv dreves na vpliv treh dogodkov z znanim časom nastanka, na podlagi lastnosti odziva datirati podobne odzive v preteklosti in primerjati odzive različnih drevesnih vrst. Na treh lokacijah smo vzorčili skupno 147 dreves različnih drevesnih vrst (bukev, rdeči bor, veliki in mali jesen, gorski javor, smreka, lipa, navadni oreh, maklen), vključno z referenčnimi vzorci dreves, ki niso bila podvržena delovanju dejavnika. Pri 91 drevesih smo uspešno izdelali drevesne kronologije in z uporabo metode kazalnih let ugotovili leta, ki so glede na rast izstopala. Pri ostalih drevesih (večinoma črnem gabru, lipi in gorskemu javorju) nismo uspeli razbrati branik, oz. so drevesne kronologije močno odstopale od povprečja vzorcev. V analizi rasti za leto, ki je sledilo dogodku, smo šibak odziv na vpliv drobirskih tokov zaznali na lokaciji pod Javorščkom, ne pa tudi v Srpenici in Nikovi. Vrste so se na lokacijah odzvale podobno. Ker smo zaznali odziv le na eni lokaciji, nismo uspeli rekonstruirati dogodkov v preteklosti. Debris flows can transport large amounts of material, and therefore present a significant threat to infrastructure and human life. In this research, we used tree ring analyses to quantify the tree response to three debris flow events for which we know the time of origin. Based on the attributes of these response patterns, we tried to date similar responses in the past and compared the patterns among different tree species. Together, we sampled 147 trees across a range of species (beech, Scots pine, common ash, manna ash, sycamore maple, Norway spruce, common walnut, field maple, small-leaved lime, and European hop-hornbeam), including reference samples of trees that were not affected by debris flow activity. For 91 trees, we constructed tree ring chronologies and used pointer-year analysis to identify years that had abnormal growth. For remaining trees (mostly European hop-hornbeam, small-leaved lime and sycamore) we could not easily distinguish their tree rings or their chronologies did not match with the average of other samples. Growth patterns following debris flow events showed a weak response at the Javoršček site, and no clear responses at the other two sites. Tree species responded similarly at the same locations. Due to the lack of a clear response pattern, we were not able to reconstruct past events.