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V prispevku smo analizirali in primerjali pomlajevanje po vetrolomih v letih 2008 in 2017. Ugotavljamo, da so gostote naravnega mladja med raziskovalnimi objekti in znotraj njih zelo različne in so posledica različnih ekoloških razmer v času ujme in po njej. Začetne gostote tri (vetrolom 2017) oz. štiri leta (vetrolom 2008) po ujmi so znašale približno 2100 do 23.000 osebkov na hektar. Zmes je bila bolj podobna, od klimaksnih vrst sta prevladovali smreka in bukev. Pomembno začetno gonilo sukcesije je precejšnja zastopanost pionirskih in svetloljubnih vrst, kot so iva, jerebika in breza. Avtorji izsledke raziskave dopolnjujemo z gozdnogojitvenimi smernicami za obnovo gozdov. Po ujmi smo pri tehnični sanaciji pozorni, da ne poškodujemo obstoječega pomladka, ki ima velik vlogo pri obnovi. Prevladuje naj naravna obnova gozdov, za umetno se odločamo v zaostrenih ekoloških razmerah, ko pričakujemo malo naravnega mladja ali to ni razvito. Pri umetni obnovi po zgledu iz tujine vnašamo jelko in hrast. Obžetev izvajamo točkovno in ne površinsko po celotni umetno obnovljeni površini, saj z njo odstranjujemo naravno mladje. V sistem obnove je treba vpeljati preverjanje uspešnosti saditve. In this paper, we analysed and compared regeneration after the 2008 and 2017 windthrow events. We found that the densities of natural regeneration between and within research sites were very diverse due to different ecological conditions during and after disturbance. Initial densities after three (windthrow 2017) or four years after the disturbance ranged from about 2,100 to 23,000 individuals per ha. Concerning species composition, spruce and beech were dominant among the late-successional species, while there was a considerable representation of pioneer and light-demanding species, such as willow, rowan, and birch, which made an important contribution to early successional forest recovery. The results of the research are supplemented with silvicultural guidelines for forest restoration. During post-disturbance salvage logging, attention is needed not to damage the existing advanced regeneration, which plays a major role in forest restoration. Natural regeneration should predominate, while artificial regeneration should be used on sites where we expect little or no natural regeneration. When using artificial restoration, following examples from abroad, silver fir and oak should be used more often. Weedings should be focused and not superficially employed over the entire artificially restored area, as it removes natural regeneration. Planting performance assessment must be introduced in the restoration system.

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.

An inventory of tree microhabitats was done in two unmanaged forests (Kobile and Ravna gora forest reserves) and one managed beech forest in SE Slovenia. The purpose of this study was to determine the influence of forest management, natural disturbances, and tree characteristics on microhabitat patterns. Forest structure and microhabitats were recorded in systematically placed plots (500 m2 in size) across each area. In total, we inventoried 849 trees on 54 plots and 1833 tree microhabitats. The results showed that forest management had no significant influence on the abundance of microhabitats per tree, but there were differences regarding microhabitat type between managed and unmanaged sites. There were substantially more microhabitats related to standing dead and live habitat trees in unmanaged forest (e.g. woodpecker cavities, insect galleries and bore holes, branch holes, dead branches and fruiting bodies of fungi), whereas in managed forests there were more tree microhabitats related to management (e.g. exposed heartwood, coarse bark, and epiphytic plants). The results also indicate that disturbance, tree diameter, vitality, and species influence the density, diversity, and occurrence of tree microhabitats. V bukovih gozdovih na območju Gorjancev (JV Slovenija) je bil jeseni 2014 opravljen popis drevesnih mikrohabitatov (DM). Skupno 54 ploskev velikosti 500 m2 je bilo sistematično postavljenih na treh raziskovalnih območjih (v pragozdnem rezervatu Ravna gora in gozdnem rezervatu Kobile ter v bližnjem gospodarskem gozdu). Zabeležili smo 1833 drevesnih mikrohabitatov na 849 drevesih. Namen študije je bil ugotoviti, kako gospodarjenje, naravne motnje ter sestojne značilnosti vplivajo na pojav DM. Podatke smo analizirali s programoma Excel in SPSS z neparametričnimi metodami. Ugotovili smo, da način gospodarjenja ne vpliva značilno na številčnost DM na drevo, vpliva pa na vrsto DM. V obeh rezervatih je bilo zabeleženih več DM, povezanih z odmrlimi in starimi drevesi (dupla ptic, izletne odprtine in rovi podlubnikov ter žuželk, vejne votline, večje odmrle veje in trosnjaki gliv), v gospodarskem gozdu pa več DM, povezanih z gospodarjenjem (izpostavljena beljava, razbrazdana skorja in epifiti). Prav tako smo ugotovili, da na gostoto, raznolikost in pojav DM vplivajo tudi naravne motnje, premer in stanje drevesa ter drevesna vrsta.

An inventory of tree microhabitats was done in two unmanaged forests (Kobile and Ravna gora forest reserves) and one managed beech forest in SE Slovenia. The purpose of this study was to determine the influence of forest management, natural disturbances, and tree characteristics on microhabitat patterns. Forest structure and microhabitats were recorded in systematically placed plots (500 m2 in size) across each area. In total, we inventoried 849 trees on 54 plots and 1833 tree microhabitats. The results showed that forest management had no significant influence on the abundance of microhabitats per tree, but there were differences regarding microhabitat type between managed and unmanaged sites. There were substantially more microhabitats related to standing dead and live habitat trees in unmanaged forest (e.g. woodpecker cavities, insect galleries and bore holes, branch holes, dead branches and fruiting bodies of fungi), whereas in managed forests there were more tree microhabitats related to management (e.g. exposed heartwood, coarse bark, and epiphytic plants). The results also indicate that disturbance, tree diameter, vitality, and species influence the density, diversity, and occurrence of tree microhabitats. V bukovih gozdovih na območju Gorjancev (JV Slovenija) je bil jeseni 2014 opravljen popis drevesnih mikrohabitatov (DM). Skupno 54 ploskev velikosti 500 m2 je bilo sistematično postavljenih na treh raziskovalnih območjih (v pragozdnem rezervatu Ravna gora in gozdnem rezervatu Kobile ter v bližnjem gospodarskem gozdu). Zabeležili smo 1833 drevesnih mikrohabitatov na 849 drevesih. Namen študije je bil ugotoviti, kako gospodarjenje, naravne motnje ter sestojne značilnosti vplivajo na pojav DM. Podatke smo analizirali s programoma Excel in SPSS z neparametričnimi metodami. Ugotovili smo, da način gospodarjenja ne vpliva značilno na številčnost DM na drevo, vpliva pa na vrsto DM. V obeh rezervatih je bilo zabeleženih več DM, povezanih z odmrlimi in starimi drevesi (dupla ptic, izletne odprtine in rovi podlubnikov ter žuželk, vejne votline, večje odmrle veje in trosnjaki gliv), v gospodarskem gozdu pa več DM, povezanih z gospodarjenjem (izpostavljena beljava, razbrazdana skorja in epifiti). Prav tako smo ugotovili, da na gostoto, raznolikost in pojav DM vplivajo tudi naravne motnje, premer in stanje drevesa ter drevesna vrsta.

Forest managers are often required to restore forest stands following natural disturbances, a situation that may become more common and more challenging under global change. In parts of Central Europe, particularly in mountain regions dominated by mixed temperate forests, the use of relatively low intensity, uneven-aged silviculture is a common management approach. Because this type of management is based on mimicking less intense disturbances, the restoration of more severe disturbance patches within forested landscapes has received little attention. The goal of this paper is to synthesize research on the restoration of forests damaged by disturbances in temperate forests of Slovenia and neighbouring regions of Central Europe, where uneven-aged silviculture is practiced. Research indicates that active management aimed at favouring mixed uneven-aged forest reduces the risk of disturbance and improves the resilience of stands. Salvage logging may have positive or negative effects on regeneration, much of which is due to the method applied and the quality of work. The most prominent factors that negatively affect restoration are: lack of advanced regeneration and decomposed woody debris, high altitude, steep slopes, dense ground vegetation, and overbrowsing. Planting or sowing should be applied in post-disturbance forests where many negative factors interact and where a high demand for sustainability of forest ecosystem services is present.

Drevesna sestava jelovo-bukovih gozdov se v prostoru in času spreminja. Nanjo vplivajo številni naravni in antropogeni dejavniki, ki delujejo neposredno ali posredno. Oblikovanje usmeritev za gojenje gozdov zato zahteva dobro poznavanje delovanja lokalnih ekoloških, zgodovinskih, gospodarskih in splošnih okoljskih dejavnikov. V prispevku prikazujemo sintezo štirih skupin raziskav, ki smo jih izpeljali v dinarskih jelovo-bukovih gozdovih v zadnjem desetletju in obravnavajo: 1) ekologijo pomlajevanja v manjših in srednjih vrzelih, 2) odziv sestojev v pragozdu Perućica na motnje srednjih jakosti (vetrolomi), 3) dolgoročne spremembe v vrstni sestavi pragozdov v jugovzhodni Evropi, in 4) odvisnost pomlajevanja v gospodarskih gozdovih od gozdnogojitvenega sistema. Namen prispevka je prikazati vlogo jelke v razvoju jelovo-bukovega gozda ter poudariti procese, ki vodijo v njeno sobivanje ali izločanje. Raziskave ekologije pomlajevanja nakazujejo, da je jelka uspešnejša na posebnih mikrorastiščih (hladnejše in vlažnejše razmere, odmrla drevesa, večja skalovitost, nižji pH tal, skromne svetlobe razmere). Na vetrolomnih površinah srednjih jakosti prevlada bukev, jelka pa se nasemeni kasneje v strnjena bukova mladovja. Naše raziskave niso potrdile hipoteze o lažjem uveljavljanju jelke v večjih sestojnih vrzelih gospodarskih gozdov. Spremembe vrstne sestave pragozdov v Sloveniji in jugovzhodni Evropi nakazujejo nazadovanje jelke v zadnjih petdesetih letih, kar je posledica več skupin vzrokov, še posebej zračnega onesnaženja in objedanja po divjadi. V Sloveniji je zmanjševanje deleža jelke v Dinaridih izrazito hitro. Primerjave z jugovzhodno Evropo kažejo, da so sicer raznovrstne strategije uveljavljanja jelke v Sloveniji neuspešne zaradi visokih gostot velikih rastlinojedih parkljarjev. The tree species composition of silver fir and beech forests has changed in space and time due to a number of direct and indirect natural and anthropogenic causal factors. Forming silvicultural guidelines, therefore, requires a sufficient understanding of the ecological, historical, economic and general environmental factors that influence silver fir-beech forests. In this paper, we present a synthesis of four research projects carried out in Dinaric silver fir-beech forests in the last decade: 1) regeneration ecology in small and medium canopy gaps 2) stand response to intermediate wind disturbance in the old-growth silver fir-beech Perućica forest 3) long-term changes in tree species composition of old-growth forests in South East Europe and 4) interdependence between regeneration and silvicultural systems.The aim of the paper is to show the role of silver fir in the development of silver fir-beech forest, and to highlight the processes that lead to its coexistence or exclusion. Research on the ecology of regeneration suggests that silver fir regenerates better on special microsites (e.g. coolersites with more soil moisture, CWD, high rock coverage, lower pH of the soil, poor light conditions). In medium sized gaps beech is dominant, while silver fir establishes itself later under the young beech canopy. Our research did not confirm the hypothesis of better regeneration success of silver fir in larger canopy gaps in managed forests. Repeated inventories from forest reserves in Slovenia and South-Eastern Europe show that silver fir declined in the last fifty years due to a variety of causes, primarily from air pollution and ungulate browsing. In Slovenia in particular, a drastic reduction of the share of silver fir occurred rapidly. Comparisons with South-Eastern Europe suggest that a wide range of regeneration strategies of silver fir in Slovenia failed because of high densities of ungulates.

Visoki pajesen je ena bolj razširjenih tujerodnih drevesnih vrst v Sloveniji. Najpogosteje se razrašča zunaj gozda, včasih pa ga najdemo tudi v gozdnem prostoru. V naših gozdovih je kemično zatiranje prepovedano, zato smo preizkusili tri vrste mehanskega zatiranja te vrste. Najuspešnejša metoda je bila puljenje celotnih osebkov, najmanj pa lomljenje enoletnih poganjkov. Mehansko zatiranje je najučinkovitejše, če ga kombiniramo z drugimi ukrepi, kot so: malopovršinsko pomlajevanje, skrb za polnilno plast, uporaba gozdnogojitvenih sistemov, ki pospešujejo vrstno in strukturno pestrost sestojev ter pospeševanje in sajenje hitrorastočih, rastišču primernih domorodnih vrst. The tree of heaven is one of the most widespread non-native tree species in Slovenia. In most areas, its spread occurs in non-forested areas, yet recent observations indicate it is becoming more common within some forest ecosystems as well. Because chemical treatment is banned in Slovenia, this study tested the effectiveness of three mechanical control treatments. Breakage of annual and biennial shoots was not successful the best treatment was total removal by pulling seedlings and saplings. Mechanical control of invasive tree species is more effective if combined with other management approaches, such as practicing silviculture that promotes vertically diverse stands of native tree and shrub species, particularly small-scale silviculture that maintains a subcanopy layer.

This paper presents the effects of deer browsing on regeneration, and subsequent consequences for the species composition, structure, and function of Slovenian forests. We begin with a synthesis of international and domestic research regarding the relationship between deer and forest ecosystems. We then present the silvicultural measures that can influence this relationship, with particular emphasis on the current situation and applications in Slovenia. In general, the situation in core deer area has improved over the past decade, but in some regions of Slovenia the density of deer does not allow for sustainable regeneration of all native tree species, especially fir and oak. This makes it difficult to adapt forests to climate change, particularly in forests recovering from severe natural disturbances. Finally, we present a proposal for a coordinated experiment involving wildlife managers and foresters, which could yield valuable insight into the relationship between deer and forest stands, and thus improve management of forests in the future. V prispevku prikazujemo, kakšni so vplivi velikih rastlinojedih parkljarjev na obnovo, s tem pa na drevesno sestavo, strukturo, kakovost in odpornost slovenskih gozdov. V uvodnem delu, na podlagi izsledkov tujih in domačih raziskav, predstavljamo nekaj temeljnih značilnosti razmerja med velikimi rastlinojedimi parkljarji (VRP) in gozdnim ekosistemom. Prikazujemo, kako na ta odnos lahko vplivamo z gozdnogojitvenimi ukrepi in na podlagi izsledkov novejših raziskav na tem področju navajamo oceno trenutnega stanja v slovenskih gozdovih. Na splošno se razmere v osrednjih območjih VRP glede na prejšnja desetletja izboljšujejo, vendar v nekaterih predelih Slovenije gostote velikih rastlinojedih parkljarjev ne omogočajo trajnostne obnove vseh domačih vrst, še posebno jelke in hrasta. To otežuje prilagajanje gozdov na podnebne spremembe, kar je še posebno izrazito na površinah, ki so jih prizadele naravne ujme. Na koncu prispevka predstavljamo predlog poskusnega usklajenega ukrepanja upravljavcev divjadi, lastnikov gozdov in gojiteljev, kar bi lahko prispevalo k večjemu razumevanju odnosa med velikimi rastlinojedimi parkljarji in gozdnimi sestoji ter boljšemu upravljanju gozdov v prihodnosti.

The tree of heaven is one of the most widespread non-native tree species in Slovenia. In most areas, its spread occurs in non-forested areas, yet recent observations indicate it is becoming more common within some forest ecosystems as well. Because chemical treatment is banned in Slovenia, this study tested the effectiveness of three mechanical control treatments. Breakage of annual and biennial shoots was not successful; the best treatment was total removal by pulling seedlings and saplings. Mechanical control of invasive tree species is more effective if combined with other management approaches, such as practicing silviculture that promotes vertically diverse stands of native tree and shrub species, particularly small-scale silviculture that maintains a subcanopy layer. Visoki pajesen je ena bolj razširjenih tujerodnih drevesnih vrst v Sloveniji. Najpogosteje se razrašča zunaj gozda, včasih pa ga najdemo tudi v gozdnem prostoru. V naših gozdovih je kemično zatiranje prepovedano, zato smo preizkusili tri vrste mehanskega zatiranja te vrste. Najuspešnejša metoda je bila puljenje celotnih osebkov, najmanj pa lomljenje enoletnih poganjkov. Mehansko zatiranje je najučinkovitejše, če ga kombiniramo z drugimi ukrepi, kot so: malopovršinsko pomlajevanje, skrb za polnilno plast, uporaba gozdnogojitvenih sistemov, ki pospešujejo vrstno in strukturno pestrost sestojev ter pospeševanje in sajenje hitrorastočih, rastišču primernih domorodnih vrst.

Namen prispevka je presoja raziskovalnega dela v rezervatih in tudi naravovarstvena ocena gozdnih rezervatov s poudarkom na ohranjanju naravne biotske pestrosti. Izmerili smo količino (volumen) in kakovost (debelinska struktura, struktura različnih razkrojnih stadijev) ostankov odmrlih dreves, ki sta lahko enostavna in dobra kazalnika naravnosti in biotske raznovrstnosti. Rezultati so jasno pokazali velike količine ostankov odmrlih dreves, nakopičenih v rezervatih s prostorninami od 21,4 m3/ha do 239 m3/ha in povprečjem 116,4 m3/ha (mediana = 106,0 m3/ha), kar je bilo bistveno več kot v okoliških gozdovih. Struktura odmrlega drevja v rezervatih je pokazala veliko kakovost, saj so debelejši ostanki različnih faz razkroja predstavljali velik delež. Glede na to in glede na aktualna evropska priporočila (30%50 m3/ha v gospodarskih gozdovih) lahko sklepamo, da relativno majhna mreža rezervatov (

V raziskavi smo analizirali razvoj gozdnih sestojev, prizadetih po naravni ujmi. Osredotočili smo se na primerjavo razvoja vegetacije med saniranimi (sečnja in spravilo sta bila izvedena) in nesaniranimi (sečnja in spravilo nista bila izvedena) deli poškodovanih gozdnih sestojev. Izmerili smo značilnosti podmladka na 45 ploskvah, postavljenih na sedmih objektih v J in Z Sloveniji. Rezultati nakazujejo razlike med obema načinoma (ne)ukrepanja po posameznih analiziranih kazalcih. Pod določenimi pogoji je lahko neukrepanje po ujmi tudi boljša izbira za razvoj vegetacije in preprečevanje neugodnih biotskih ter abiotskih procesov po naravni ujmi. In our research we analyzed the development of forest stands affected by natural disturbance. We focused on the comparison of vegetation development on salvaged (felling and salvage logging were performed) and non-salvaged (felling and salvage logging were not performed) parts of the damaged forest stands. We measured characteristics of the regeneration on 45 plots in seven study sites in S and W Slovenia. The results indicate differences between the both treatments under certain conditions, doing nothing after a disturbance can represent a better choice for the development of vegetation and prevention of unfavorable biotic and abiotic processes after a natural disturbance.

In Slovenian forests, ice storms are a very frequent natural disturbance process and have an important impact on forest structure, composition, and function. Moreover, tree damage due to ice accumulation usually leads to reduced value of timber and has negative economic consequences for forestry and forest owners. Indirectly, ice damage increases the susceptibility of forest trees to a variety of diseases and pests. Žled je v naših gozdovih ena glavnih naravnih motenj, ki pogosto zelo vpliva na dinamiko gozdne vegetacije in funkcije gozdov. Poškodovanost zaradi žleda ponavadi povzroča zmanjšano vrednost lesa in povzroči negativne ekonomske posledice za gozdarstvo in lastnike prizadetih gozdov. Posredno se zaradi žleda povečuje tudi dovzetnost gozdnega drevja za različne bolezni in škodljivce. Različnih stopenj poškodovanosti gozdnega drevja ne povzroča le žledenje samo, temveč nanjo posredno in neposredno vplivajo tudi drugi dejavniki. V prispevku skušamo odgovoriti na vprašanje, kako ob pojavu žledoloma različni dejavniki vplivajo na vrsto in obseg poškodovanosti gozdnega drevja. Namen našega prispevka je opisati glavne povezave med različnimi rastiščnimi dejavniki in lastnostmi gozdnih sestojev ter stopnjo oziroma vrsto poškodb na gozdnem drevju, ki nastane zaradi žledenja. Navajamo tudi smernice za izboljšanje stabilnosti in odpornosti gozdov proti žledu ter glavne ugotovitve, kako s pomočjo najnovejših tehnologij in metod nastalo škodo čim ustrezneje ocenimo.

The paper evaluates the role of the forest reserve network in Slovenia for both research purposes and conservation of biodiversity. In particular, we quantified the quantity and quality of dead wood in 16 forest reserves in Slovenia as a general indicator of conservation value. The total volume (standing and lying trees) ranged from 21,4 to 239 m3/ha, with a mean of 116,4 m3/ha, which is markedly higher than in surroundings managed forests. In most of the reserves, large dead trees in advanced stages of decay were present, indicating the high quality of dead wood in reserves. Given that recent recomendations from the literature call for 30-50 m3/ha of dead wood in managed forest to maintain the majority of saproxylic species, coupled with the small area of forest reserves in Slovenia (

The tree species composition of silver fir and beech forests has changed in space and time due to a number of direct and indirect natural and anthropogenic causal factors. Forming silvicultural guidelines, therefore, requires a sufficient understanding of the ecological, historical, economic and general environmental factors that influence silver fir-beech forests. In this paper, we present a synthesis of four research projects carried out in Dinaric silver fir-beech forests in the last decade: 1) regeneration ecology in small and medium canopy gaps; 2) stand response to intermediate wind disturbance in the old-growth silver fir-beech Perućica forest; 3) long-term changes in tree species composition of old-growth forests in South East Europe; and 4) interdependence between regeneration and silvicultural systems.The aim of the paper is to show the role of silver fir in the development of silver fir-beech forest, and to highlight the processes that lead to its coexistence or exclusion. Research on the ecology of regeneration suggests that silver fir regenerates better on special microsites (e.g. coolersites with more soil moisture, CWD, high rock coverage, lower pH of the soil, poor light conditions). In medium sized gaps beech is dominant, while silver fir establishes itself later under the young beech canopy. Our research did not confirm the hypothesis of better regeneration success of silver fir in larger canopy gaps in managed forests. Repeated inventories from forest reserves in Slovenia and South-Eastern Europe show that silver fir declined in the last fifty years due to a variety of causes, primarily from air pollution and ungulate browsing. In Slovenia in particular, a drastic reduction of the share of silver fir occurred rapidly. Comparisons with South-Eastern Europe suggest that a wide range of regeneration strategies of silver fir in Slovenia failed because of high densities of ungulates. Drevesna sestava jelovo-bukovih gozdov se v prostoru in času spreminja. Nanjo vplivajo številni naravni in antropogeni dejavniki, ki delujejo neposredno ali posredno. Oblikovanje usmeritev za gojenje gozdov zato zahteva dobro poznavanje delovanja lokalnih ekoloških, zgodovinskih, gospodarskih in splošnih okoljskih dejavnikov. V prispevku prikazujemo sintezo štirih skupin raziskav, ki smo jih izpeljali v dinarskih jelovo-bukovih gozdovih v zadnjem desetletju in obravnavajo: 1) ekologijo pomlajevanja v manjših in srednjih vrzelih, 2) odziv sestojev v pragozdu Perućica na motnje srednjih jakosti (vetrolomi), 3) dolgoročne spremembe v vrstni sestavi pragozdov v jugovzhodni Evropi, in 4) odvisnost pomlajevanja v gospodarskih gozdovih od gozdnogojitvenega sistema. Namen prispevka je prikazati vlogo jelke v razvoju jelovo-bukovega gozda ter poudariti procese, ki vodijo v njeno sobivanje ali izločanje. Raziskave ekologije pomlajevanja nakazujejo, da je jelka uspešnejša na posebnih mikrorastiščih (hladnejše in vlažnejše razmere, odmrla drevesa, večja skalovitost, nižji pH tal, skromne svetlobe razmere). Na vetrolomnih površinah srednjih jakosti prevlada bukev, jelka pa se nasemeni kasneje v strnjena bukova mladovja. Naše raziskave niso potrdile hipoteze o lažjem uveljavljanju jelke v večjih sestojnih vrzelih gospodarskih gozdov. Spremembe vrstne sestave pragozdov v Sloveniji in jugovzhodni Evropi nakazujejo nazadovanje jelke v zadnjih petdesetih letih, kar je posledica več skupin vzrokov, še posebej zračnega onesnaženja in objedanja po divjadi. V Sloveniji je zmanjševanje deleža jelke v Dinaridih izrazito hitro. Primerjave z jugovzhodno Evropo kažejo, da so sicer raznovrstne strategije uveljavljanja jelke v Sloveniji neuspešne zaradi visokih gostot velikih rastlinojedih parkljarjev.

Raziskava je potekala v treh pragozdnih rezervatih Šumik, Pečka in Rajhenavski Rog. V vsakega od pragozdov smo postavili 20 objektov, vsak objekt pa je bil sestavljen iz semenske pasti, iz kletke proti objedanju divjadi in kontrolne ploskve. Ugotovili smo, da je v rezervatu Šumik v kletkah preživelo 10 % več osebkov kakor izven nje. Preživetje jelke je bilo za 30 % boljše v kletkah kakor na kontrolnih ploskvah. V Pečki smo našteli največjo gostoto bukovih klic. V kletkah proti objedanju je preživelo 13 % vsega spremljanega mladja v času študije, kar je za 4 % manj kakor na kontrolnih ploskvah. Tudi preživetje jelke je bilo za 5 % slabše v kletkah kakor na kontrolnih ploskvah, kjer je preživelo 40 % vseh spremljanih jelk. V pragozdu Rajhenavski Rog smo našteli največ javorovega in jelovega semena. V kletkah proti objedanju je preživelo za 16 % vsega mladja oz. klic kar je za 6 % več kot na kontrolni ploskvi. Delež jelke, ki je preživela, je bil višji v kletkah in sicer za 8 %. Ugotovljena je bila negativna povezava med preživetjem v kletkah kakor izven njih. Ugotovili smo, da imajo na pomlajevanje in preživetje klic močen negativen vpliv manjši plenilci listja kot so polži in suša. The study examined seed production and seedling survival in three virgin forest reserves - Šumik, Pečka and Rajhenavski Rog. In each of the primeval forests 20 objects were placed, each object consisting of a seed trap, a deer exclosure plot, and a control plot. In Šumik, we found that 10% more individuals survived in the cages than in control plots, and there was 30% higher survival of fir in the cages than in the control plots. In Pečka, we found the highest density of beech one year old seedlings. In the deer exclosure plots, 13% of all monitored seedlings survived until the end of the study, which is 4% less than in the control plots. Survival of fir trees was also 5% lower in the cages than in the control plots, where 40% of all monitored fir trees survived. In Rajhenavski Rog, we counted the most maple and fir seeds. In the deer exclosures, 16% of all one year old seedlings survived, which was 6% more than in the control plot. The percentage of fir survivors was 8% higher in the cages. Over all reserves, there was higher survival in the exclosures compared to control plots, except Pečka. We found that mortality agents, such as snails and drought, had a strong negative effect on regeneration survival.

Planinski smrekov gozd v dolini Lopučnice se nahaja v Triglavskem narodnem parku in je del gozdnega rezervata Savica-Ukanc. Po leta 1883 opuščenemu gospodarjenju je prepuščen naravnemu razvoju. V dolini Lopučnice smo po 39 letih od prve meritve (Cvenkel in Mlinšek, 1983) in 24 letih od druge meritve (Poljanec, 1998) ponovili meritve na trajni raziskovalni ploskvi, ki jo je Cvenkel leta 1983 postavil kot del raziskav gozdnih rezervatov v Sloveniji. Namen naloge je bil predstaviti spremembe v zgradbi in razvoju planinskega smrekovega gozda v obdobju 1983–2022. Raziskovali smo spreminjanje velikosti vrasti in smrtnosti v obdobjih 1983–1998 in 1998–2022. Drevesna sestava je v proučevanem obdobju ostala nespremenjena. Osnovni kazalci sestoja za leto 2022 so imeli naslednje vrednosti: N = 388 dreves/ha, G = 57,60 m2/ha, V = 675 m3/ha. Skupna letna smrtnost se je v obdobju med letoma 1983 in 1998 iz 1,3 %/leto povišala na 1,5 %/leto za obdobje med letoma 1998 in 2022. Letne stopnje smrtnosti za obe opazovani obdobji so imele podoben vzorec, pri čemer so bile najvišje vrednosti v prvem debelinskem razredu. Skupna letna vrast 0,06 %/leto v obdobju med letoma 1983–2022 se je znižala na 0,04 %/leto v obdobju med letoma 1998–2022. Stopnja preraščanja med debelinskimi razredi za oba proučevana obdobja je bila najvišja v četrtem debelinskem razredu, najmanjša pa v prvem debelinskem razredu. V opazovanem obdobju (1983–2022) je prišlo do upada števila dreves, neznačilnih sprememb vrednosti temeljnice in manjše spremembe v lesni zalogi. Ta vzorec potrjuje, da se gozd še vedno nahaja v optimalni fazi, vendar je primerjava porazdelitve dreves po debelinskih razredih pokazala na postopno staranje sestoja. The mountain spruce forest in the Lopučnica valley is located in Triglav National Park and is part of the Savica-Ukanc forest reserve. After abandoning managment since 1883, it has been left to natural development. After 39 years since the first measurement (Cvenkel and Mlinšek, 1983) and 24 years since the second measurement (Poljanec, 1998) we repeated the measurements on a permanent research plot in the Lopučnica valley, which was established by Cvenkel in 1983 as part of research on forest reserves in Slovenia. The purpose of the thesis is to present the changes in the structure and development of the mountain spruce forest in the period 1983-2022. We quantified mortality and recruitment rates in two periods: 1983–1998 and 1998–2022. The tree composition remained unchanged during the observed period. The basic stand indicators for 2022 had the following values: N = 388 trees/ha, G = 57.60 m2/ha, V = 675 m3/ha. The annual mortality rate increased from 1,3 % in 1983–1998 to 1,5 % in 1998–2022. The annual mortality rates for both observed periods had a similar pattern, with the highest values in the smaller diameter classes. The annual recruitment rate decreased from 0,06 % in 1983–1998 to 0,04 % in 1998–2022. Annual recruitment rates for both studied periods were highest in the larger diameter classes, and the lowest in the smaller diameter classes. During the observed period (1983–2022), there was a decline in the number of trees, uncharacteristic changes in the basal area and smaller changes in tree volume. This pattern confirms that the forest is still in an optimal phase, but a comparison of the diameter classes revealed a gradual aging of the stand.

Pragozdni rezervati so odličen objekt za analizo naravnega razvoja sestojev, ki poteka brez vpliva človeka, oziroma je ta močno zmanjšan. Leta 1984 so bile v Rajhenavskem Rogu postavljene stalne raziskovalne ploskve s skupno površino 1,91 ha, namenjene analizi odraslega sestoja. Leta 2020 je bila izvedena peta ponovitev popisa. Smrtnosti in vrasti jelke in bukve si niso podobne in se skozi čas spreminjajo. V celotnem obdobju ni bilo zaznane vrasti jelke skozi merski prag. Prav tako so se močno zmanjšale njene gostote v prvem debelinskem razredu (DBR), čemur vzrok so predvsem velike populacije jelenjadi. Stalno odmiranje in pomanjkanje vrsti jelke je privedlo do splošnega upada jelke skozi vse DBR. Nasprotno, število bukve v prvem DBR skozi vsa obdobja vztrajno narašča, njena vrast pa je vidna tudi v ostalih DBR. Ti trendi napovedujejo vztrajno nadomeščanje jelke z bukvijo, kar lahko dolgoročno privede do spremenjene drevesne sestave. V zadnjih treh meritvah je opazno večanje števila živih-zlomljenih dreves, od vetra izruvanih dreves in dreves, ki so podlegla padcem drugih dreves, kar kaže na večanje ekstremnih vremenskih pojavov, predvsem manjših vetrolomov. Old-growth reserves serve as natural laboratories for analysing the dynamics of forest stands without direct influence of humans. In 1984, permanent research plots were placed in the Rajhenavski Rog with a total area of 1.91 ha intended for the analysis of long-term demography. A fifth iteration of the census was carried out in 2020. Mortality and recruitment of beech and fir, the two dominant species, varied over time. Throughout the monitoring period, no ingrowth of the fir was detected, and its density in small diameter classes declined over time, likely due to large populations of red deer. The lack of recruitment and continuous mortality also resulted in a general decline in fir across all diameter classes. In contrast, the number of beech in the smallest diameter class has steadily increased over time, and recruitment of beech is notable across most diameter classes. These trends highlight a steady replacement of fir by beech, which may lead to a long-term change in species composition at the site. In the last three measurements, there has been an increase in the number of live-snapped, uprooted, crushed trees, indicating an increase in disturbance induced tree mortality, especially smaller windthrow events.

Gozdni rezervat Pogorevc je bil več kot 50 let prepuščen naravnem razvoju. Leta 1991 je bilo izločenih pet stalno vzorčnih ploskev. Leta 2017 smo ponovili meritve na vseh petih ploskvah. Drevesom smo ponovno izmerili premer, določili smo stanje drevesa (živo, mrtvo drevo), na podlagi mrtvih osebkov smo opisali tip odmiranja in določili stopnjo razpada. V rezervatu se je ponudila edinstvena priložnost, da smo preučili demografske razmere v gozdu, ki počasi prehaja v pozno sukcesijski stadij. Ugotovili smo, da se je gostota dreves zmanjšala za dobrih 37%, kar lahko poleg naravnemu odmiranju pripišemo vetrolomu iz leta 2017. Zmanjšuje se delež rdečega bora (Pinus sylvestris L.), povečuje pa se delež smreke (Picea abies L.). Mortaliteta na ploskvah je velika, pomlajevanja pa je izredno malo, pomlajuje se le smreka. Smrtnost dreves se na letni ravni giblje med 0,54 % in 2,51 %. Najvišja smrtnost na letni ravni je pri rdečem boru (2,89 %), bukvi (1,72 %) in najnižja smrtnost je pri smreki (0,92 %). The Pogorevc forest preserve has been untouched and left to develop naturally on its own for over 50 years. Five individual lots that had been sampled continuously were last sampled In 1991. In 2017, measurements were once again taken on all five lots. We re-measured the diameters of the trees, assessed their condition (as either alive or dead), and determined the type of death and degree of decay in the dead specimens. The preserve provided a unique opportunity to study the demographic condition of the forest, which is slowly transitioning into the late-succession stage. We found that the tree density has decreased by more than 37%, which – aside from natural death – can be attributed to heavy windfall in 2017. The proportion of the Scots pine (Pinus sylvestris) is decreasing, and the proportion of the European spruce (Picea abies) is increasing. Tree mortality on the lots is high, and the degree of regeneration is very low, the only exception being the spruce. The annual mortality of the trees is somewhere between 0.54 % and 2.51 %. The highest annual death mortality was measured in the Scots pine (2.89 %) and the European beech (1.72 %), and the lowest in the spruce (0.92 %).

V gozdnem rezervatu Repiško smo leta 2014 izvedli ponovno polno premerbo drevja na trajni raziskovalni ploskvi. Šlo je za prvo ponovitev po popisu ničelnega stanja v letu 1986. Poleg tega smo postavili še sistematično mrežo vzorčnih ploskev v rezervatu Tisovec in Repiško. Namen naloge je bil preko gostote, debelinske strukture, smrtnosti in pomlajevanja prikazati dinamiko sestoja. Na trajni ploskvi v rezervatu Repiško nismo beležili večjih sprememb v drevesni sestavi. S 43 % deležem je v skupnem številu dreves še vedno vodila jelka, pred smreko in bukvijo (obe 23 %). Povprečna velikost temeljnice v Tisovcu je znašala 57,33 m2/ha, v Repiškem pa 53,91 m2/ha. V obeh primerih se je največje število osebkov nahajalo v debelinskem razredu do 30 cm. Tudi na mreži ploskev smo ugotovili primerljivo vrstno sestavo in nekoliko višjo gostoto (663 dreves/ha). V Tisovcu je znašala gostota 887 dreves/ha. Med vrstami pa so prevladovale bukev (36 %), jelka (25 %) in smreka (19 %). Stopnja smrtnosti v Repiškem je znašala 0,61 %/leto. Najvišje stopnje smo beležili v prvem debelinskem razredu. Povprečni volumen odmrlega lesa v Tisovcu je znašal 46,5 m3/ha in se je večinoma nanašal na mokovec in bukev, v Repiškem pa je večina 116,0 m3/ha volumna odmrlih drevesnih ostankov odpadla na jelko. V obeh primerih so v volumnu prednjačile podrtice. V obeh rezervatih ugotavljamo primerljive gostote pomladka. V Tisovcu smo zabeležili 14.440 rastlin/ha, med katerimi je z 39 % prevladoval gorski javor. V Repiškem pa je med 13.620 rastlin/ha vodilno vlogo igrala jelka (48 %). Pomlajevanje je v obeh primerih zadovoljivo. Večje poškodbe po parkljasti divjadi niso zaznavne. In 2014 we carried out a full repetition of measurements on the permanent research plot in the Repiško forest reserve. It was the first re-measurement following the initial establishment in 1986. In addition, we set up a systematic grid of sample plots in the Repiško and Tisovec reserves. The aim of the thesis was to infer stand dynamics using measurements of density, diameter structure, mortality, and regeneration. We did not record any significant changes in species composition on the permanent plot in Repiško. With a 43 % share of the total number of trees fir still prevailed over spruce and beech (both 23 %). The average basal area in Tisovec was 57,33 m2/ha and 53,91 m2/ha in Repiško. In both cases, the largest number of stems was located in the diameter class up to 30 cm. On the sampling grid, we found comparable species composition and slightly higher density (663 trees/ha). In Tisovec the density was 887 trees/ha. The dominant species were beech (36 %), fir (25 %) and spruce (19 %). The mortality rate in Repiško was 0,61 %/year. The highest mortality rates were recorded in the first diameter class. The average dead tree volume in Tisovec was 46,5 m3/ha and was mostly related to whitebeam and beech. In Repiško fir contributed most to the 116,0 m3/ha volume of dead tree remnants. Logs were prevalent type of dead wood in both cases. In both reserves we found comparable regeneration densities. We recorded 14.440 stems/ha in Tisovec, of which 39 % were sycamore. In Repiško fir was the most abundant (48 %) of the total 13.620 stems/ha. Regeneration was satisfactory in both cases. We did not detect major deer damage.

Analizirali smo spremembe pritalne vegetacije (zelišč in grmovnic) v pragozdnih rezervatih Pečka in Strmec na podlagi ponovnega popisa 85 vegetacijskih ploskev iz leta 1983. Ploskve smo ponovno popisali leta 2015 po prvotni, Piskernikovi fitocenološki metodi. Na osnovi primerjave treh kazalcev diverzitete (vrstna pestrost, Shannonov indeks in indeks vrstne poravnanosti) smo ugotovili znatno zmanjšanje vrstne pestrosti pritalne vegetacije v obeh rezervatih. Analiza sprememb številčnosti na podlagi ekofizioloških in funkcionalnih lastnosti rastlin je pokazala, da se je najbolj znižala diverziteta fanerofitov in vrst z večjo potrebo po svetlobi, medtem ko je ostala pestrost večine sencovzdržnih rastlin in geofitov nespremenjena. Prav tako se je znižalo povprečno zastiranje nekaterih vrst z visokimi vrednostmi specifične listne površine (SLA). Sklepamo, da je omenjeno posledica vzajemnih učinkov sestojne dinamike (poslabšanja svetlobnih razmer zaradi povečanega zastiranja podstojnih sestojnih plasti) ter objedanja s strani velikih rastlinojedov. Čeprav v nobenem izmed rezervatov nismo ugotovili termofilizacije (premik k bolj toploljubni vrstni sestavi) združb pa zmanjšanje številčnosti zmerno vlagoljubnih vrst ter zmanjšanje SLA-jev združb (tehtana aritmetična sredina SLA-jev vseh vrst na ploskvi) v Pečki vseeno nakazujejo na vpliv klimatskih sprememb na pritalno vegetacijo v raziskovalnem obdobju, kar pa z zasnovo naše raziskave ne moremo nedvoumno potrditi. Zato bi bile na to temo dobrodošle dodatne raziskave. We investigated changes in understory vegetation biodiversity in two old-growth Abies- Fagus forest reserves (Pečka and Strmec) in SE Slovenia between 1983 and 2015. Resurveys of 85 historical semipermanent vegetation plots were done using the same method (Piskernik phytosociological method) as was used in the original surveys. According to changes in diversity measures (species richness, Shannon diversity index and species evenness index) significant diversity losses during the study period were found in both reserves. The largest declines were observed for light-demanding species and phanerophytes highly susceptible to browsing, while diversity of shade-tolerant species, especially geophytes, showed little change. These changes were consistent with the canopy closure and increase in red deer densities in both reserves during the study period. In Pečka we also documented a decline of some shade-tolerant, moisturedemanding species and an overall decrease of community mean specific leaf area (SLA) values. We argue that this could be an influence of climate change (increase in mean annual temperatures and decrease in annual precipitation during study period), but this assumption clearly needs further investigation.

V pragozdu Perućica v Bosni in Hercegovini smo raziskali vpliv treh srednjepovršinskih vetrolomov na razvoj gozdov v vetrolomnih vrzelih. Na vsaki vetrolomni površini smo postavili tri raziskovalne ploskve, velikosti 25 x 25 m. Na enak na%in smo postavili raziskovalne ploskve v kontrolnih sestojih. Na raziskovalnih ploskvah na vetrolomih smo izmerili vsa stoje%a drevesa in mladovje. Na vsaki raziskovalni ploskvi na vetrolomu smo odvzeli izvrtke desetim drevesom, ki so bila najbliţje središ%u ploskve. Izvrtke smo odvzeli tudi desetim drevesom ve%jih dimenzij na celotni površini vetroloma. Izmerili smo vsa razpadajo%a drevesa ter jih razvrstili v pet razredov glede na stopnjo razgradnje. Zgradba sestojev se je po vetrolomih spremenila. Svetloljubni listavci se pojavijo, %e je dovolj svetlobe, v nasprotnem primeru se pojavi bukev. Najprej se pojavijo svetloljubni listavci, za njimi bukev in šele na koncu jelka. Vsak vetrolom je posledica ene ve%je ujme. Nastala vrzel se je po ujmi po%asi širila. Na vetrolomih Osoje in Tunjemir se je pestrost drevesnih vrst pove%ala, ne pa tudi na vetrolomu Skakavac. Mladje svetloljubnih listavcev se je pojavilo po vetrolomih, mladje sencozdrţnih drevesnih vrst je bilo prisotno ţe pred motnjami. Bukev bolj odreagira na pove%an dotok svetlobe kot jelka. Povpre%ni debelinski prirastek gorskega javorja je najve%ji pri drevesih, ki so vzklila po vetrolomu. Srednjepovršinski vetrolomi pomembno vplivajo na razvoj gozdov. In the Perućica old-growth forest in Bosnia and Herzegovina, we investigated the impact of three intermediate wind disturbances upon the forest development of windthrow gaps. Three research areas 25 x 25 m were prepared in each windthrow gap. Research areas were prepared in the same way also in control stands. In the research areas, all standing trees and young growths were measured. In each research area in the windthrow gaps, core samples were taken from ten trees that were closest to the centre of the area. Core samples were taken also from ten larger trees in the entire windthrow surface. All decaying trees were measured and they were classified into five classes, depending on the level of decomposition. The structure of stands changed after windfall. Deciduous trees that prefer ample light conditions appear in case of ample light, otherwise beeches apper. First, decidiuous trees appear, followed by beeches and finally by firs. Each windfall results from a larger natural disaster. A gap caused by a natural disaster spreads slowly. In windfalls Osoje and Tunjemir, the variety of tree species increased, which does not apply for the windfall Skakavac. The growth of decidiuous trees that prefer ample light conditions appeared after wind disturbances, whereas the growth of shade-tolerant tree species was present already before the disturbances. Beeches reacts more strongly to more ample light than firs. The average radial growth of sycamore maple is largest in case of trees that germinated after the wind disturbance. Intermediate wind disturbances have a significant impact upon forest development.

V diplomski nalogi smo ugotavljali zmožnost širjenja robinije (Robinia pseudoacacia L.) v notranjost gozda iz skupin matičnih dreves, ki rastejo na gozdnem robu. Poleg tega smo ugotavljali tudi poglavitni način širjenja (semena, koreninski poganjki, panjevski poganjki) in ekološke razmere, ki omogočajo ter pospešujejo širjenje robinije. V ta namen smo iz izhodiščnih točk, ki so bile postavljene v bližini matičnih sestojev robinije, potegnili transekt v notranjost gozda. Skupno smo naredili tri transekte, na vsakem transektu pa smo postavili pet ploskev velikosti 5 x 5 m. Rezultati so potrdili uspešnost širjenja robinije v notranjost sestoja, saj ima pomembno vlogo v pomladku in je v vseh višinskih razredih druga najpomembnejša drevesna vrsta. Ugotovili smo, da širjenje robinije poteka predvsem prek koreninskih poganjkov, medtem ko je pomen semenskih poganjkov majhen. Zaradi tega ima velik vpliv na gostoto mladja robinije prav gostota matičnih dreves v bližini rastišča. Rezultati so pokazali, da je pomemben dejavnik pri pomlajevanju robinije tudi svetloba, čeprav je pomen le te manjši od pričakovanega. Na pomlajevanje robinije ima negativen učinek zastrtost rastišča z zeliščno plastjo, ki verjetno vpliva na manjši delež robinije na močno osvetljenih rastiščih. Močnejše širjenje robinije je možno preprečiti že z obstoječimi ali nekoliko prilagojenimi načini gospodarjenja, ki vključujejo malopovršinsko gospodarjenje in pomlajevanje pod zastorom matičnega sestoja, ter izvedbo negovalnih ukrepov, ki zagotavljajo čim večjo stabilnost in odpornost na naravne ujme, medtem ko je smiselnost bolj intenzivnega zatiranja vprašljiva. Vlogo robinije je potrebno ponovno pretehtati in se sprijazniti, da je postala del našega naravnega okolja. This thesis examines the invasion success of black locust (Robinia pseudoacacia L.) in a mature forest stand on Rožnik. We also tried to determine the prevalent type of regeneration (seeds, root sprouts, stump sprouts) and the optimal ecological conditions that enable or encourage the growth and spread of black locust. For that purpose, we located adult black locust trees growing on the edge of the study area and placed transects toward the forest stand interior. All together, we made three such transects and placed five plots measuring 5x5 m on each of them. The results showed that black locust does spread successfully into the inner parts of the forest. It was abundant in all height classes. We found that black locust spread primarily by means of its underground shoots, while seed regeneration was rare. As such, the density of young black locust plants depends on the density of larger black locust trees. The results suggest that light conditions also play a role in the spread of black locust, but the importance of light was less than expected. A potential obstacle for invasion of black locust is the understory herbaceous layer which % especially in well lit areas % may prevent further spread. A more pronounced spread of black locust may be prevented with existing adapted management measures, including small-scale silviculture and adult-tree management. It can also be prevented by tending native tree growth, enabling a higher stability and resistance to natural disturbances. The sensibility of intensive and direct removal is, however, questionable. The role of black locust is yet to be determined but we must face the fact that is has become a part of our environment.

V pragozdnem ostanku Rajhenavski Rog so bile leta 1984 izločene tri stalne raziskovalne ploskve s skupno površino 1,91 ha, ki so bile izmerjene tudi leta 1994. Leta 2010 smo ponovili meritve na vseh treh ploskvah. Preučevali smo spreminjanje velikosti vrasti in smrtnosti v obdobjih 1984-1994 in 1994-2010. Skupna letna smrtnost se je v obdobju 1994-2010 v primerjavi z obdobjem 1984-1994 iz 1 % povišala na 1,2 %, stopnja smrtnosti jelke (Abies alba Mill.) pa je v obeh meritvenih obdobjih močno presegala stopnjo smrtnosti bukve (Fagus sylvatica L.). Do največjega povišanja smrtnosti je prišlo, tako pri jelki kot pri bukvi, pri drevesih s premerom večjim od 70 cm. Skupna letna vrast 1,8 % v obdobju 1984-1994 se je povišala na 2,6 % v obdobju 1994-2010. Prišlo je do izrazitega povečanja vrasti novih bukovih dreves v populacijo, vrasti jelke pa že od prvih meritev leta 1984 nismo zaznali. Skupna vrast se je povišala pri drevesih s premerom do 20 cm, pri debelejših drevesih pa se je vrast v obdobju 1994-2010, v primerjavi z obdobjem 1984-1994, znižala. Število bukev na ploskvah se viša in sedaj znaša 84 % vseh dreves, delež jelke pa se je znižal na 16 %. Rezultati nakazujejo na nadaljnje zmanjševanje deleža jelke v populaciji in vse večjo prevlado bukve v Rajhenavskem pragozdu. In 1984 three permanent plots totalling 1,91ha were established in the Rajhenavski Rog old-growth forest. These plots were re-measured in 1994 and 2010. We quantified mortality and recruitment rates in two periods: 1984-1994 and 1994-2010. The annual mortality rate increased from 1% in 1984-1994 to 1,2% in 1994-2010. The mortality rate of silver fir (Abies alba Mill.) heavily exceeded that of European beech (Fagus sylvatica L.) in both of the analyzed periods. The highest increase in mortality was recorded for trees with dbh greater than 70 cm for both silver fir and European beech. The annual recruitment rate increased from 1,8% in 1984-1994 to 2,6% in 1994-2010. We recorded a large increase in the recruitment of beech trees in the 1994-2010 period, while there was no recruitment of silver fir in the last 26 years. For trees with dbh lower than 20 cm, we recorded an increase in annual recruitment, while a decrease in recruitment was found for trees with dbh greater than 20 cm. The number of beech trees on the plots increased and as a result beech currently represents 84% of all trees. The share of silver fir in the forest decreased and the results suggest this process will also continue in the future, leading to a further increase in beech in the Rajhenavski Rog old-growth forest.

Namen diplomskega dela je preučiti vzajemno delovanje dveh motenj, ki vplivata na pomlajevanje: nastanka vrzeli zaradi odmiranja jelke in objedanja jelenjadi in srnjadi na pomlajevanje v Kočevskem Rogu. Za raziskovalni objekt je bil izbran Rajhenavski pragozd. Sedanje stanje podmladka so primerjali s stanjem v letu 1984. Za primerjavo je bila analizirana sestava mladja v bližnjih ogradah izven pragozda. Ugotovljeno je, da je Rajhenavski pragozd močno izpostavljen selektivnemu objedanju predvsem jelenjadi, gostota jelk je 132 rastlin/ha, gostota javorja je 212 rastlin na ha, medtem ko je gostota bukve 13928 rastlin/ha. V ograjah v bližini so rezultati močno razlikujejo: bukev 8627 rastlin/ha, jelka 4993 rastlin/ha, javor 8007 rastlin/ha Gostota jelenjadi se je povečala v zadnjih 50 letih in območje Rajhenavskega pragozda ji zagotavlja ugodne habitatne razmere. Na dolgoročno vrstno zgradbo in na zmanjšanje števila vrst v Kočevskem Rogu bo vplival vrstno-specifični odziv naveč različnih, medsebojno vplivajočih motenj in okoljskih dejavnikov. The purpose of this research was to study the mutual effects of fir decline and deer browsing on tree regeneration in Kočevski Rog. The first part of the study was conducted in an old-growth forest of Rajhenav. The current number of tree saplings and seedlings was compared to the data from 1984. To further compare, an identical study was performed in the fenced areas in the vicinity of Rajhenav forest, where the effect of deer browsing is eliminated. The conclusion is that Rajhenav old-growth forest is under severe selective browsing pressure. The density of fir seedlings is 132/ha, the density of maple seedlings is 212/ha, while the average beech density is 13928/ha. The numbers in fences are significantly different: 8627 beech saplings and seedlings/ha, 4993/ha for fir and 8007/ha for maple. The population density of deer has rapidly increased in the past 50 years and the Rajhenav old-growth forest provides a favorable habitat conditions. The long-term tree species distribution and reduced diversity resulted from species-specific responses to interacting disturbances and environmental factors.

Namen naloge je bil v pragozdu Rajhenavski Rog proučiti razvojno dinamiko vrzeli, obnovitvene cikle ter narediti terestično analizo vrzeli. Uporabljen je bil severnoameriški pristop. Rajhenavski Rog meri 51,14 ha, za analizo smo izbrali severni del pragozda (10,16 ha). Raziskavo smo opravili leta 2006 in zabeležili 87 vrzeli in 377 vrzelnikov. Prevladujejo majhne vrzeli. Pogled v zgodovino vrzeli kaže na večkratno širjenje vrzeli in njihov nepretrgan razvoj. Z analizo smo ugotovili, da ima največ vrzeli od 2 do 5 vrzelnikov. Stanje pragozda nakazuje razvoj v smeri bukovega gozda, saj delež jelke med vrzelniki narašča. Pomlajevanje poteka malopovršinsko v jedrih, kjer rastni prostor obvladuje bukev. Razvojna dinamika vrzeli povzroča nastanek malopovršinsko heterogenih sestojev. Severnoameriški pristop raziskovanja je primeren za raziskovanje razvojne dinamike. Potrebno pa je metodo izvajati natančno in jo ustrezno prilagoditi na terenu. Ugotovitve je tako mogoče upoštevati in prenesti znanje v gospodarske gozdove. The purpose of the paper was to study the stand dynamic and regeneration patterns in the virgin forest Rajhenavski Rog, and to carry out a terrestrial analaysis of the gap. In order to do this, a North-American approach was used.The forest of Rajhenavski Rog measures 51,14 ha the analysis was carriedout in the north part of Rog (10,16 ha). The research was done in 2006,whereby 87 gaps and 377 gapmakers were found. The majority of the gaps are small-sized. The history of the gaps shows their repeated widening and continuous development. The analysis showed that most of the gaps have 2 to 5 gapmakers, and that the virgin forest is in its beech spreding stage, as the percentage of fir gapmakers is rising. Regeneration is small- scale in cores, where the growing space is used by the beech. The stand dynamics of the gaps cause the occurrence of small-scale heterogeneous stands. Necessary is to work precisely and adjust work on the field. Knowledge of research is in need for transfer into management forests.

V trinajstih gozdnih rezervatih, ki so delno ali v celoti privatne oziroma občinske lasti, so bile opravljene meritve večjih mrtvih drevesnih ostankov z namenom določitve ohranjenosti in naravnosti zgradbe gozdov. Izračunana in analizirana je bila njihova prostornina ter ugotovljena debelinska in razkrojna porazdelitev ter vrstna sestava. Na podlagi meritev na stalnih vzorčnih ploskvah so bile opravljene primerjave parametrov odmrlih dreves med gozdnimi rezervati in okoliškimi nezavarovanimi gozdovi. S pomočjo študija literature so bile ugotovljene tudi razlike med drugimi evropskimi gozdnimi rezervati in med pragozdovi. Raziskava je pokazala, da je večina rezervatov z vidika odmrlega drevja dobro ohranjena in ima zaradi tega visok raziskovalni pomen. Med vsemi gozdnimi rezervati je znašala srednja vrednost volumna mrtvih drevesnih ostankov 118 m3/ha, kar je zelo visoka vrednost, ki se že približuje vrednostim v okoliških pragozdnih rezervatih. V bližnjih nezavarovanih gozdovih je znašala srednja vrednost 22 m3/ha. Odmrlo drevje je bilo v rezervatih tudi debelejše in starejše ter večinoma po vrstni sestavi bolj rastišču primerno, kot v okoliških gospodarskih gozdovih. In the thirteen forest reserves, which are partly or fully private or owned by municipalities, coarse woody debris was quantified to assess naturalness and inform future conservation status of these reserves. Deadwood quantity (volume) and quality (diameter sizes, decomposition stages, broadleaf/conifer ratios, logs/snags ratios and species compositions) were measured and compared with data from nearby managed forests, based on forest inventory plots from the Slovenian Forest Service. The quantity and quality of dead wood found in the reserves indicate a high degree of naturalness. Over all the reserves, the mean volume of deadwood was 118 m3/ha, a value that is approaching the amount found in old-growth forests in the region. In contrast,average dead wood volume in surrounding managed forests was 22 m3/ha,and individual logs and snags had much smaller diameters than in reserves. The differences in the quantity and quality of dead wood found in reserves and managed forests are similar to those reported in other regions of Europe.