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Tree recruitment models are important for predicting the dynamics of uneven-aged forests. Previous studies of recruitment of European beech, Norway spruce and silver fir have shown different ecological amplitudes of these species. However, recruitment in uneven-aged stands and the values of environmental factors at which the greatest and poorest recruitment can be expected remain poorly explained. The main objectives of this study were to 1) explain how 39 stand, site and climatic factors and their interactions influence the number of recruited trees in uneven-aged forests; 2) determine the optimal and critical ranges of influential factors, including stand basal area, number of trees, proportion of tree species, shade casting, soil pH, site productivity, temperature and precipitation; and 3) estimate the maximum expected response of recruitment to changes in stand density while controlling for the effect of other limiting factors. A Tobit censored regression model was used to consider that the observed range of the number of recruited trees is censored at zero. The models were parametrized and validated using 30,963 forest inventory plots (200 m2 each) in uneven-aged forests in Slovenia. The models, which used 9 stand, 6 site and 3 climatic factors, explained 15 %, 10 % and 8 % of the total variation of the number of recruited spruce, fir and beech, respectively. Stand structure was the most important factor, with stand basal area (BA) and the proportion of the studied species having the greatest effect. Site factors including soil pH and rockiness were important for fir recruitment. The number of recruited beech and spruce was positively influenced by decadal precipitation. Higher temperatures decreased recruitment of spruce. Beech was the only species sensitive to shade casting. Recruitment of beech was higher if shade was imposed by tree species other than beech. The optimal and critical ranges of limiting factors differ between species. The model suggests that the optimal stand basal area for recruitment of beech is ≤ 19 m2/ha, which is higher than that for spruce (≤ 16 m2/ha) but lower than that for fir (≤ 28 m2/ha). The maximum predicted response of the studied species to changes in stand basal area shows that stand density control is efficient for regulating recruitment of spruce and beech, but not for fir. The suggested sensitivities and threshold values may be used in individual tree growth models or simulation–optimization studies in support of forest management decisions. Nasl. z nasl. zaslona. Opis vira z dne 5. 12. 2022. Bibliografija: str. 11-13.

Prirastne značilnosti, distribucija vode v drevesu, horizontalna in vertikalna električna upornost živih tkiv in odziv na mehanske poškodbe so bile proučene pri 35 posekanih in 428 rastočih jelkah (Abies alba Mill.) z dveh reprezentativnih dinarskih jelovo-bukovih rastišč (Bistra in Ravnik). Radialna rast v prsni višini se je izkazala kot najbolj občutljiv kazalec prizadetosti oz. zdravosti drevesa. Za prizadete jelke je značilna dehidracija beljave in pojav mokrin na lokaciji neobarvane jedrovine, ki radiirajo v beljavo ("patološko mokro srce"). Horizontalna (pri stoječih drevesih) in vertikalna (na prečnih prerezih kolutov) električna upornost živih tkiv senzitivno karakterizirata zdravstveno stanje ali cenotski status dreves. Reakcija dreves na poškodbe je večterna in se odraža kot (a) "fosilizacija" starejših diferencirajočih se celic v kambijevi coni, (b) v močni parenhimatizaciji zaradi sproščanja skorjinega tlaka in rastnih napetosti v lesu (nastanek barierne cone) ter (c) "juvenilizaciji" in (d) deorientaciji po poškodovanju. Growth characteristics, water distribution in stems, horizontal and vertical electrical resistance of living tissue, and response to mechanical injury were studied on 35 felled and 428 growing silver fir (Abies alba Mill.) trees from two representative Dinaric silver fir-beech stands (Bistra and Ravnik). Radial growth at breast height proved to be the most sensitive indicator of tree health. Affected silver fir trees are characterised by dehydration of the sapwood and the appearance of wet wood at the location of the uncoloured heartwood radiating into the sapwood ('pathological wet heart'). The horizontal (in standing trees) and vertical (in cross-sections of the discs) electrical resistance of living tissues is a sensitive indicator of tree health or social status. The response of trees to wounding is diverse and manifests itself in (a) 'fossilisation' of older differentiating cells in the cambium zone, (b) severe parenchymatization due to the release of bark pressure and growth stresses in the wood (formation of the barrier zone), and (c) 'juvenilisation' and (d) disorientation of cells after wounding.

V prispevku na primeru jelke predstavljamo sedem regresijskih modelov za modeliranje priraščanja dreves s podatki periodičnih meritev na stalnih vzorčnih ploskvah. Poleg polinomske regresije, modela z dodanim šumom in mešanega linearnega modela, predstavljamo regresijo z naravnimi zlepki in tri modele z omejenimi odvisnimi spremenljivkami: truncated regression, tobit regression in grouped data regression. Modele lahko uporabimo, kadar se zaradi načina merjenja in zaokroževanja podatkov ter hierarhičnosti podatkov srečamo z rezanimi ali krnjenimi slučajnostnimi spremenljivkami, nezveznostjo odvisne spremenljivke in pristransko oceno prirastka. Pri pojasnitvi debelinskega priraščanja 21.013 jelk na 4.405 ploskvah v obdobju 1990–2014 v raznomernih gozdovih v dinarskih jelovo-bukovjih so vsi modeli pokazali podoben vpliv prsnega premera, sestojne temeljnice, temeljnice debelejših dreves, raznomernosti, nagiba, nadmorske višine in le manjše razlike v regresijskih koeficientih in merah prileganja. Največje povprečne napovedi prirastka daje tobit model, mešani model pa se najbolj prilega podatkom. V primerjavi z drugimi modeli model z zlepki kaže na počasnejše zmanjševanje prirastka zelo debelih jelk po kulminaciji prirastka. We present seven alternative statistical models for modelling tree diameter increment with data from permanent sampling plots. In addition to the polynomial regression model, we present a regression model with added random noise, a mixed linear model, regression with natural splines, and three models with limited dependent variables: truncated regression, tobit regression and grouped data regression. The models may be used when dealing with truncated or censored variables, biased estimation of the increment due to censoring and rounding down, or when having multilevel data. The parametrization of the models was done using 21,013 fir trees on 4,405 plots in the period 1990–2014 in uneven-aged Dinaric fir-beech forests. All models showed a similar effect of tree diameter, stand basal area, basal area of larger trees, diameter structure diversity, altitude and slope. There were only minor differences in the regression coefficients and fit measures. The highest increment predictions were given by the tobit model. The mixed model fit the data best and, compared to the other models, predicted a slower decrease in the growth of large-diameter trees after growth culmination.

Naravne snovi so spojine ali ekstrakti, ki izvirajo iz živih organizmov ter navadno izkazujejo biološko delovanje. So osnovna surovina za zdravila naravnega izvora. V farmakognoziji se ukvarjamo z njihovim izborom, karakterizacijo, identifikacijo in uporabo. Pogost pristop k odkrivanju potencialno zdravilnih naravnih snovi je preizkušanje učinkov rastlinskih izvlečkov, ki nas v povezavi s kromatografskimi separacijami vodi do izolacije biološko aktivnih molekul. Njihove kemijske strukture ugotavljamo s sodobnimi spektroskopskimi in spektrometrijskimi metodami in nadaljujemo s preizkušanjem njihovega farmakološkega delovanja. Ajda predstavlja bogat vir hranil z ugodnim vplivom na zdravje, zato njena poraba v skladu s popularnostjo zdravega načina življenja narašča. Poleg zdravju koristnih snovi pa ajda vsebuje tudi manj znane, fototoksične fagopirine, ki pod vplivom svetlobe oksidirajo biološko snov in povzročijo njene poškodbe. Za zagotavljanje varnosti ajde in njenih izdelkov je treba fagopirine vrednotiti tako s prehranskega kot s farmacevtskega vidika. Ne nazadnje gre tudi za spojine s potencialno terapevtsko uporabnostjo, na primer v fotodinamični terapiji. Razvili smo učinkovit postopek ekstrakcije fagopirinov z uporabo raztopine acetona in vode. Ugotovili smo, da so najprimernejši material za pridobivanje fagopirinov ajdovi cvetovi. Razvili smo preprosto in občutljivo metodo tekočinske kromatografije visoke ločljivosti s fluorescentno detekcijo. Metoda je primerna za analizo vzorcev ajde in kot izhodišče za razvoj preparativne metode za izolacijo fagopirinov. Ugotovili smo, da je poleg osnovne molekule fagopirina F v zeli ajde še vsaj sedem njegovih derivatov. Te derivate smo kromatografsko ločili na posamezne frakcije. Vrednotili smo jih z UV-Vis absorpcijo, masno spektrometrijo in NMR spektroskopijo. Ugotovili smo strukturi dveh novih fagopirinov, ki se razlikujeta po skupinah, pripetih na naftodiantronski obroč. Fagopirin F je že predhodno znana spojina z dvema piperidinskima obročema, fagopirin E je spojina s piperidinskim in pirolidinskim obročem, fagopirin A pa je spojina z dvema pirolidinskima obročema. Dokazali smo, da v ajdi ni fagopirinov, temveč zgolj protofagopirini kot njihove predstopnje z necikliziranim naftodiantronskim obročem. Po raztopitvi v ekstrakcijskem topilu in pod vplivom svetlobe se protofagopirini pretvorijo v fagopirine. Raziskovali smo topnost, fluorescenco in UV-Vis spektre fagopirinov v različnih topilih iz različnih vzorcev ajde. Za kvantitativno vrednotenje vsebnosti fagopirinov je treba pridobiti čiste spojine kot referenčne spojine. Raziskovalci namesto fagopirina kot referenčne spojine uporabljajo hipericin iz šentjanževke, ki pa zaradi nekoliko drugačne strukture in s tem drugačne absorpcije pri spektrofotometrijski detekciji ni ustrezen za točno kvantitativno vrednotenje fagopirinov. Naše ugotovitve in novo razvite metode bodo pripomogle k nadaljnjemu raziskovanju fagopirinov in vrednotenju vsebnosti in varnosti ajdovih izdelkov. V drugem delu doktorskega dela smo se ukvarjali z izvlečki debla navadne jelke. Izvlečki debel različnih vrst borovcev so znani po vsebnosti polifenolnih spojin z zanimivimi farmakološkimi učinki, predvidoma povezanimi z antioksidativnim delovanjem. Najbolj znan, raziskan in uporabljan je izvleček lubja obmorskega bora (Pinus maritima), Pycnogenol®. Ugotovili smo, da so izvlečki navadne jelke učinkovitejši antioksidanti od Pycnogenola® tako v in vitro antioksidativnih testih, kot tudi na humanih celičnih linijah, izoliranih iz periferne krvi. Komponente izvlečka lubja smo kromatografsko ločili z normalnofazno kolonsko kromatografijo pri zvišanem tlaku in reverznofazno tekočinsko kromatografijo visoke ločljivosti. Vsebovane spojine smo identificirali z metodami masne spektrometrije, UV-Vis absorpcijske spektroskopije in s primerjavo z referenčnimi spojinami. Identificirali smo šest fenolkarboksilnih kislin (galno, homovanilno, protokatehujsko, p-hidroksibenzojsko, vanilno in p-kumarno), tri flavonoide (katehin, epikatehin in katehintetrametileter) in štiri lignane (taksiresinol, 7-(2-metil-3,4-dihidroksitetrahidropiran-5-iloksi)-taksiresinol, sekolariciresinol in lariciresinol). Nadaljevali smo s farmakološkim testiranjem. Ugotovili smo, da izvleček zmanjša nastajanje ateroskleroze pri budrah na kronični aterogeni dieti. Ovrednotili smo vpliv izvlečka in dveh v njem prisotnih fenolnih kislin, p-kumarne in protokatehujske, na izolirana podganja srca, podvržena akutnim ishemijsko-reperfuzijskim poškodbam. Ugotovili smo, da je izvleček značilno zmanjšal poškodbo srčnega tkiva, merjeno preko sproščanja laktat-dehidrogenaze in zmanjšal pojavnost aritmij. p-kumarna in protokatehujska kislina nista imeli tako izrazitih učinkov, zato verjetno samo delno prispevata k sinergističnemu delovanju v izvlečku prisotnih učinkovin. Kot ustrezno surovino za raziskovanje in uporabo smo oblikovali izvleček, raztopljen v polietilenglikolu. Pojavila se je potreba po ugotavljanju vsebnosti vode v tovrstnih vzorcih. Uveljavljena in dostopna Karl-Fischer metoda z opazovanjem spremembe barve pri končni točki titracije ni bila ustrezna, saj je bil izvleček obarvan. Zato smo razvili preprosto in finančno dostopno titracijsko metodo za ugotavljanje vsebnosti vode v obarvanih vzorcih, pri kateri končno točko titracije zaznamo spektrofotometrijsko. Tako ovrednoten izdelek predstavlja dobro osnovo za nadaljnje raziskovanje in razvijanje novih prehranskih dopolnil, kozmetičnih izdelkov in zdravil. Natural products are compounds or extracts that originate from natural sources and usually exhibit biological activity. They are raw materials for natural medicines. Pharmacognosy encompasses their selection, characterization, identification and use. Bioassay-guided fractionation of plant extracts linked to chromatographic separation techniques leads to the isolation of biologically active compounds whose chemical structures can readily be determined by modern spectroscopic and spectrometric methods, followed by testing of their pharmacological activity.Buckwheat contains many healthy nutrients, and its consumption is therefore increasing. The plant contains phototoxic compounds called fagopyrins that can act as photosensitisers upon excitation with visible light causing fagopyrism, but these compounds have received little research attention. To assure adequate safety of buckwheat and its products, fagopyrins should be characterized from a nutritional and pharmaceutical point of view. Nevertheless, fagopyrins are not only health-threatening compounds but also potent photodynamic agents that deserve further research. In this work, fagopyrins extraction procedure was improved employing a mixture of acetone and water. Flowers were recognized as the best material for the extraction. A chromatographic analysis of fagopyrins was performed by developing a simple, sensitive HPLC analytical method of high-resolution employing fluorescence detection. The developed method is a good starting point for a preparative method that would enable the isolation of pure compounds. At least eight fagopyrin derivatives were observed upon isolation and were characterized via UV-Vis absorption, NMR spectroscopy and mass spectrometry. The structures of two new fagopyrins were elucidated. Fagopyrin F is a previously known compound that consists of naphthodianthrone scaffold and two piperidine moieties. Fagopyrin A differentiates by two pyrrolidine moieties instead of piperidine moieties, and fagopyrin E consists of one pyrrolidine and one piperidine moiety. The existence of protofagopyrins that originate in buckwheat and can transform into fagopyrins upon light exposure was confirmed. Information on solubility, fluorescence and UV-Vis absorbance in different solvents were obtained. The need for reference compounds of different fagopyrins that would allow proper quantitative evaluation of buckwheat samples still remains. Researchers use hypericin for that purpose, but we recognize its use as inadequate due to the different structure and consequently uncomparable absorbance in spectrophotometric detection. Our methods complement the existing knowledge regarding fagopyrins and will facilitate their further isolation and analysis of their biological activity. In the second part of our work, silver fir trunk extracts were investigated. Extracts from the bark of different conifer species are known to contain various polyphenols that possess interesting pharmacological activities. So far the most extensive research was done on the antioxidative extract of the maritime pine (Pinus maritima) bark Pycnogenol®, which is widely used in food supplements and cosmetic products. We have shown that antioxidant activity of silver fir (Abies alba) extract is higher comparing to the maritime pine bark extract in vitro and in cultured cells. Components of the extract were separated with normal phase flash chromatography and reversed phase HPLC. Structures of individual compounds were elucidated by mass spectrometry, UV-Vis absorption spectroscopy and comparison to reference compounds. Six phenolic acids were identified (gallic, homovanillic, protocatehuic, p-hydroxybenzoic, vanillic and p-coumaric), three flavonoids (catechin, epicatechin and catechin tetramethyl eter) and four lignans (taxiresinol, 7-(2-methyl-3,4-dihydroxytetrahydropyran-5-yloxy)-taxiresinol, secoisolariciresinol and laricinresinol).The research was continued with pharmacological testing. It was found that the extract exerts strong antioxidative and protective effects against atherogenic diet-induced arterial wall damage. Protective effects of the silver fir extract and its compounds as well as of two phenolic acids (p-coumaric and protocatechuic acids) were also evauated against ischemia-reperfusion-induced damage in isolated rat hearts. The silver fir extract significantly reduced tissue damage (measured as the lactate dehydrogenase release rate) and shortened the duration of arrhythmias, which was not observed in the case of phenolic acids. It was concluded that the two acids are only partially responsible for the observed effects and synergism of more compounds could be present. Silver fir extract, solubilized in polyethylene glycol was developed as an appropriate raw material for research and use. A need for water determination in such samples emerged. The most accessible technique for water content determination is Karl-Fischer titration with visual detection of a titration endpoint, which was unfortunately not suitable for the analysis of the silver fir extract due to its strong colour. Therefore an appropriate method for moisture determination in coloured samples was developed employing simple equipment and spectrophotometric detection of a titration endpoint. Silver fir extract, characterized in such manner is a suitable ingredient for development of food supplements, cosmetic products and medicines.

The main objective of our study was to investigate the possible differences in the chemical composition of extractives from the bark of silver fir (Abies alba) with respect to the location of the bark sample on the tree, viz. differences in extract composition between stem bark and branch bark samples. Extractives in the bark samples from branches, depending on the distance of the sample from the trunk, were also analysed, and the stem bark samples were analysed with respect to their inner and outer parts. The results of the chemical analysis of extractives were supported by information about their antifungal and antioxidant effects. After felling and sampling silver fir trees, the collected bark samples were ground and freeze-dried. Extraction of bark samples was followed by a system of accelerated extraction using only water as a solvent. The extracts were analysed chemically using gravimetry, spectrophotometry and chromatography. Free-radical-scavenging activity was measured using the DPPH method, and the antifungal effect towards three moulds and three wood-decaying fungi was investigated with antifungal assay using the agar well diffusion method. It was found that the moisture content in bark samples decreased intensively just after the bark samples were peeled off the stem. Detailed chromatographic analysis showed that the bark extracts contained 14 compounds, among which phenolic acids, flavonoids and lignans were found to be the characteristic ones. The content of hydrophilic extractives in the branch bark samples decreased with increasing distance of the sample location from the tree stem. The largest amounts of phenolic extractives were measured in stem bark, followed by branch bark sampled at the point at which the branch entered the tree. Analysis of the separated parts of the bark showed that the outer layers of stem bark contained larger amounts of phenolic extractives, as well catechin and epicatechin, compared to the inner layers. Concentrated extracts of branch bark showed the largest free-radical-scavenging activity among the investigated samples, while strong antifungal effects of the bark extract were not found. Nasl. z nasl. zaslona. Opis vira z dne 27. 1. 2023. Article no.: 225. Bibliografija: str. 12-13. Abstract.

Non-native forest tree species have been introduced in Europe since the 16th century, but only in the second half of the 20th century the significance of the seed source origin for their economic use was recognized, resulting in the establishment of numerous provenance trials at a national, regional, European and International level, as those led by IUFRO. Breeding programs have also been launched in the continent for the most economically important species. Aim of this work is the formulation of provenance recommendations for planting of five non-native tree species in Europe (Douglas fir, grand fir, Sitka spruce, lodgepole pine and black locust), based on the information obtained from twenty countries, in the frame of the EU FP-1403 NNEXT Cost Action. The survey revealed that official and non-official national recommendations, based on provenance research results, have been elaborated and followed at a different level and extend for the above five species, but only for Douglas fir recommendations exist in almost all the participating to the survey countries. The compilation of provenance recommendations across Europe for each species is presented in the current work. Besides the recommended introduced seed sources, European seed sources are also preferred for planting, due to ease of access and high availability of forest reproductive material. European breeding programs yielding genetic material of high productivity and quality constitute currently the seed source of choice for several species and countries. Consolidation of trial data obtained across countries will allow the joint analysis that is urgently needed to draw solid conclusions, and will facilitate the development of ‘Universal-Response-Functions’ for the species of interest, rendering possible the identification of the genetic material suitable for global change. New provenance trial series that will test seed sources from the entire climatic range of the species, established in sites falling within and outside the environmental envelopes of their natural ranges, are urgently needed to pinpoint and understand the species-specific climate constraints, as well as to correlate functional traits to the seed origin and the environmental conditions of the test sites, so that the selection of suitable forest reproductive material of non-native tree species in the face of climate change can be feasible.

Non-native forest tree species have been introduced in Europe since the 16th century, but only in the second half of the 20th century the significance of the seed source origin for their economic use was recognized, resulting in the establishment of numerous provenance trials at a national, regional, European and International level, as those led by IUFRO. Breeding programs have also been launched in the continent for the most economically important species. Aim of this work is the formulation of provenance recommendations for planting of five non-native tree species in Europe (Douglas fir, grand fir, Sitka spruce, lodgepole pine and black locust), based on the information obtained from twenty countries, in the frame of the EU FP-1403 NNEXT Cost Action. The survey revealed that official and non-official national recommendations, based on provenance research results, have been elaborated and followed at a different level and extend for the above five species, but only for Douglas fir recommendations exist in almost all the participating to the survey countries. The compilation of provenance recommendations across Europe for each species is presented in the current work. Besides the recommended introduced seed sources, European seed sources are also preferred for planting, due to ease of access and high availability of forest reproductive material. European breeding programs yielding genetic material of high productivity and quality constitute currently the seed source of choice for several species and countries. Consolidation of trial data obtained across countries will allow the joint analysis that is urgently needed to draw solid conclusions, and will facilitate the development of ‘Universal-Response-Functions’ for the species of interest, rendering possible the identification of the genetic material suitable for global change. New provenance trial series that will test seed sources from the entire climatic range of the species, established in sites falling within and outside the environmental envelopes of their natural ranges, are urgently needed to pinpoint and understand the species-specific climate constraints, as well as to correlate functional traits to the seed origin and the environmental conditions of the test sites, so that the selection of suitable forest reproductive material of non-native tree species in the face of climate change can be feasible, This paper is an output from the European COST Action FP1403 ‘Non-native tree species for European forests—experiences, risks and opportunities’ (NNEXT), and specifically the Working group “Pathways”, in which all authors participated and contributed information in the relevant questionnaire

The timing of leaf phenology tends to be crucial in controlling ecosystem processes such as the acquisition of carbon and water loss as well as in controlling tree nutrient cycling. To date, tree phenology has mostly been associated with environmental control (e.g., temperature and photoperiod) in a relationship with inheritance, while it has rarely been linked with ectomycorrhizal community compositional changes through the host tree’s phenological stages. Seasonal variations of fungal communities have been widely studied, but little is known about mycorrhiza community composition changes along phenological stages. Therefore, we analyzed ectomycorrhizal communities associated with silver fir and their compositional changes during the transition between phenological stages. The phenological stages of each individual tree and time of bud break were monitored weekly for two years and, at the same time, ectomycorrhiza was harvested from selected silver fir trees. In total, 60 soil cores were analyzed for differences in the ectomycorrhizal community between phenological stages using Sanger sequencing of individual ectomycorrhizal morphotypes. A significant difference in beta diversity for an overall ectomycorrhizal community was confirmed between analyzed time periods for both sampled years. Species-specific reactions to transitions between phenological stages were confirmed for 18 different ectomycorrhizal taxa, where a positive correlation of Russula ochroleuca, Russula illota, Tomentella sublilacina, and Tylospora fibrillosa was observed with the phenological stage of bud burst. Nasl. z nasl. zaslona. Opis vira z dne 20. 12. 2021. Abstract. Bibliografija: str. 9-12.

Predstavljamo pregled raziskav Katedre za tehnologijo lesa pod vodstvom dr. Torellija o propadanju jelke (Abies alba Mill.) v Sloveniji. Raziskave v obdobju 1985-1996 so vključevale spremljanje stanja jelke s pomočjo merjenja električne upornosti (EU), anatomske in fiziološke interpretacije meritev EU, upadanje rasti in prirastka, študij fenologije, reproduktivne rasti, pojava sekundarne krošnje, ugotavljanje vlažnosti in kvalitete lesa, število sluznih celic v skorji in travmatskih smolnih kanalov v lesu ter odziv lesa in skorje na poškodovanje Investigations on silver fir (Abies alba Mill.) decline in Slovenia conducted by the Chair of Wood Science directed by Torelli are reviewed. The investigations completed within 1985-1996 include the monitoring of tree condition using an electrical resistance (ER) measuring method with anatomical and physiological interpretation of the ER readings, studies on growth reduction, and phenology, reproductive growth, development of epicormic branches, wood miosture content and wood quality, the frequency of slime cells in the bark and traumatic resin canals in wood, and the responses of wood and bark to mechanical wounding

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.

Raziskava je potekala na območju Kočevskega Roga, ki predstavlja del Dinarskega gorovja v južni Sloveniji. Raziskovalne objekte so obsegale tri, leta 2001 izsekane vrzeli z razporeditvijo vzorčnih ploskev v mreži 5 x 5 m, na katerih smo izvedli tretjo meritev razvoja mladovja. Na vzorčnih ploskvah velikosti 2, 25 m² smo ocenjevali deleže zastrtosti tal, gostoto mladja, poškodovanost mladja, drevesno sestavo in rast dominantnih osebkov. Gostota jelke, gorskega javorja in bukve v mladju se je v primerjavi z meritvijo leta 2006 zmanjšala. Delež zastrtosti tal z mladovjem se je povečal, zmanjšal pa se je delež zastiranja z zelišči, skalami in drevesnimi ostanki. Poškodbe terminalnega poganjka zaradi objedanja so se pri bukvi v primerjavi s prejšnjima meritvama zmanjšale in so bile zabeležene pri 5 % dreves, medtem pa sta se deleža močno poškodovanih osebkov jelke in gorskega javorja v primerjavi s prejšnjima meritvama povečala na 37 % za jelko in 38 % za gorski javor. Delež osebkov s pokončno razrastjo se je povečal (79 %), zmanjšala pa sta se deleža osebkov z deformacijo stebla (6 %) in osebkov s plagiotropno razrastjo (14 %). Obraten in nepričakovan trend je bil opažen pri analizi oblike poganjkov, kjer se je delež osebkov z enoosno rastjo terminalnega poganjka zmanjšal (56 %), delež osebkov z dvovrhato (36 %) in metlasto (8 %) rastjo pa se je povečal. HD razmerje se je od prejšnje meritve povečalo z 74 na 86,7. Po končani analizi podatkov smo ugotovili, da v izbranih vrzelih mladje jelke in gorskega javorja ne prerašča v zgornje višinske razrede. To lahko v prihodnosti privede do biotskega in ekonomskega siromašenja teh gozdov. The research took place in the area of Kočevski Rog, which represents a part of Dinaric Mountains in the South of Slovenia. Research plots were set up inside three, in 2001 cut down canopy gaps using 5 x 5 m grid. During the third measurement of regeneration development we assessed the ground coverage of tree regeneration and vegetation, the density of tree regeneration, browsing damage and the growth of dominant saplings on the plot. The density of silver fir, sycamore maple and beech in the first regeneration layer decreased compared to the 2006 measurement. The proportion of regeneration coverage increased, while the proportion of ground vegetation, rock coverage and coarse woody debris decreased. Damage rates of terminal beech shoots decreased to 5 %, while the proportion of severely damaged specimens of silver fir and sycamore maple increased compared to previous measurements to 37 % for silver fir and 38 % for sycamore maple. The proportion of stems with upright growth increased to 79 %, while the proportions of specimens with stem deformation (6 %) and specimens with plagiotropic growth (14 %) decreased. A reverse and unexpected trend was observed in the analysis of shoot shape, where the proportion of stems with single terminal shoots decreased (56 %), while the proportion of specimens with two terminal shoots (36 %) and broom shape growth (8 %) increased. The HD ratio has increased since the previous measurement from 74 to 86,7. After completing the data analysis, we found out that silver fir and sycamore maple do not recruit to higher regeneration layers which can cause future decrease of biotic and economic value of these forests.

Species of the genus Tuber have gained a lot of attention in recent decades due to their aromatic hypogenous fruitbodies, which can bring high prices on the market. The tendency in truffle production is to infect oak, hazel, beech, etc. in greenhouse conditions. We aimed to show whether silver fir (Abies alba Mill.) can be an appropriate host partner for commercial mycorrhization with truffles, and how earthworms in the inoculation substrate would affect the mycorrhization dynamics. Silver fir seedlings inoculated with Tuber. aestivum were analyzed for root system parameters and mycorrhization, how earthworms affect the bare root system, and if mycorrhization parameters change when earthworms are added to the inoculation substrate. Seedlings were analyzed 6 and 12 months after spore inoculation. Mycorrhization with or without earthworms revealed contrasting effects on fine root biomass and morphology of silver fir seedlings. Only a few of the assessed fine root parameters showed statistically significant response, namely higher fine root biomass and fine root tip density in inoculated seedlings without earthworms 6 months after inoculation, lower fine root tip density when earthworms were added, the specific root tip density increased in inoculated seedlings without earthworms 12 months after inoculation, and general negative effect of earthworm on branching density. Silver fir was confirmed as a suitable host partner for commercial mycorrhization with truffles, with 6% and 35% mycorrhization 6 months after inoculation and between 36% and 55% mycorrhization 12 months after inoculation. The effect of earthworms on mycorrhization of silver fir with Tuber aestivum was positive only after 6 months of mycorrhization, while this effect disappeared and turned insignificantly negative after 12 months due to the secondary effect of grazing on ectomycorrhizal root tips.

Veliki rastlinojedi parkljarji s prehranjevanjem z mladjem drevesnih vrst zavirajo naravno obnovo gozda, vplivajo na zmes mladja in delež drevesnih vrst v prihodnosti. V diplomski nalogi smo preučili vpliv izbranih rastiščnih dejavnikov glede na tip mezoreliefa na stopnjo objedenosti osebkov gozdnega mladja. Meritve smo izvedli na 196 ploskvah v GGE Grčarice, del pa tudi v GGE Stojna. Gre za jelovo-bukove gozdove. Na ploskvah smo prešteli vse mladje in ga ločili po drevesni vrsti, višini in poškodovanosti. Ocenili smo tudi ekološke dejavnike reliefa. Skupaj je bilo objedenega 58 % vsega mladja, največ na tipu mezoreliefa ravno (povprečno 83 %). Najbolj objedena drevesna vrsta je bila jelka (Abies alba) z 72 %, sledil ji je gorski javor (Acer pseudoplatanus) z 71 %. S statističnimi analizami smo potrdili vpliv težavnosti terena na stopnjo objedenosti mladja. Z večanjem naklona terena in s težjo dostopnostjo terena oziroma lokacije mladja, se je delež objedenosti mladja zmanjševal. Povezava med kritjem in objedanjem ni bila enoznačna. Objedenost mladja se je povečevala z večanjem razdalje do kritja do ca. 30 m razdalje, najvišje objedanje smo zabeležili pri najmanjši stopnji kritja. Oboje govori v prid večjem objedanju pri boljši preglednosti, kar je verjetno posledica prevladujočega objedanja s strani jelenjadi. Large herbivores that feed on seedlings of tree species delay the natural regeneration of a forest, and they influence the mixture of seedlings and the future composition of tree species. In this thesis we analysed the influence of selected habitat factors related to the type of relief on the rate of browsing damage of forest seedlings. We carried out measurements on 196 plots in GGE Grčarice and on some plots in GGE Stojna. Silver fir-beech forests predominate. We examined all seedlings on the plots by tree species, height and damage. We also assessed the ecological factors of the relief. We found that 58% of all seedlings were browsed by ungulates, most of them on flat relief (average 83%). The most severely browsed tree species was silver fir (Abies alba) with 72%, followed by sycamore maple (Acer pseudoplatanus) with 71%. Statistical analyses confirmed the correlation between the accessibility of the terrain and browsing damage to seedlings. With increasing inclination and accessibility of the terrain, the rate of damaged seedlings decreased. Browsing of seedlings increased with increasing distance to the ungulate cover up to a distance of approx. 30 m. The highest browsing was also observed at the lowest ungulate cover level. Both indicate increasing browsing with overall better visibility, which is probably due to the predominant browsing by red deer.

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.

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.

Cilj in namen diplomskega dela je bil ugotoviti, kako priprava verige motorne žage, drevesna vrsta in tip verige vplivajo na učinke pri prežagovanju lesa ter strukturo in obliko žagovine. Les bukve in jelke se je predhodno prizmiralz vertikalno krožno žago na dimenzijo 32 cm x 32 cm, napake pa se je izločilo med samim poskusom. Za prežagovanje lesa se je uporabilo motorno žago Husqvarna 372 xp, 45 cm dolg meč Stihl z 1,6 mm utorom ter verige Oregon in Stihl, katere so bile nabrušene pod tremi različnimi koti ostrine rezilcev in tremi različnimi višinami globinskih zob. Rezultati so pokazali, da se učinki prežagovanja v splošnem povečujejo z zniževanjem kota ostrine in s povečevanjem višinske razlike med rezilci in globinskimi zobi. Prežagovanje je učinkovitejše pri uporabi verig Oregon ter pri obdelavi lesa jelke. Deleži ostružkov z velikostjo 0,063 mm so večji pri manj znižanem globinskem zobu in manjših kotih ostrine rezilcev ter pri bukvi in verigah Oregon. Na dolžino ostružkov značilno vpliva kot ostrine rezilcev in drevesna vrsta, na širino drevesna vrsta in tip verige, na njegovo debelino pa višina globinskega zoba, drevesna vrsta in tip verige. Ugotovitve raziskave so uporabne za povečevanje učinkovitosti kakor tudi varovanje zdravja pri poklicnem in nepoklicnem delu z motorno žago. The aim and the purpose of the thesis was to find out how to prepare the chain of the chainsaw, tree species and the type of the chain and what is the affect at crosscutting wood and the structure and the form of sawdust. Wood of beech and fir was previously cut into the shape of prism with a vertical circular saw on a 32 cm x 32 cm, errors were eliminated during the experiment.For crosscutting wood was used a chainsaw Husqvarna 372 xp, 45 cm long sword Stihl with 1.6 mm groove and Oregon`s and Stihl`s chains which weres harpened under three different angles of edge of blades and three different heights of depth of teeth. The results showed that the effects of the cut generally increase by reducing the angle of edge of blades and by increasing the height difference between the blade and depth of a tooth. Crosscutting is more efficient in the use of Oregon`s chain and at the processing of fir wood. The proportion of chips with the size of 0,063 mm is higher in less reduced depth tooth and a small corner of the parietal blade and with beech and Oregon`s chains. On the length of the chip significantly affect the peak angle of the blade and tree species, on the width the tree species and the type of the chain, and on the thickness affect the height of depth of the tooth, tree species and the type of the chain. The research findings are useful for increasing the efficiency as well as protection of health at professional and selfwork with a chainsaw.

At the 1000km geographical distance in Dinaric montane forests of silver fir (Abies alba Mill.) and European beech (Fagus sylvatica L.), the tree response from the north-western sites towards southern, warmer and dryer sites was performed during three consecutive growing seasons (2011, 2012 and 2013). On eleven permanent plots, positioned in uneven-aged beech and fir forests above 800m along the geographical gradient, the physiological and morphological response to light intensity were measured in predefined light categories based on the analysis of hemispherical photos. Radial growth was analysed on all plots and compared to precipitation, temperature and two drought indexes. Analysis showed a decrease in the cumulative precipitation and no change in temperature between plots. Beech was most efficient in the open area light conditions, while fir proved most efficient under shelter. Physiological response for beech increased towards SE and reached its maximal values in the middle of transect, while fir%s response decreased from the NW towards SE. Tendency to plagiotropic growth decreased from NW to SE in both species. Growth response to climatic parameters is weak, stronger in fir than in beech and decreasing towards SE. Nasl. iz nasl. zaslona. Opis vira z dne 12. 11. 2019. Dokument v formatu PDF obsega 14 str. Bibliografija: str. 11-13.

Raziskava je potekala v pragozdnem rezervatu Rajhenavski Rog, v delu Dinarskega gorstva na jugu Slovenije. Šlo je za četrto izvedbo meritev mladovja v šestih vrzelih, na vzorčnih ploskvah razporejenih v mreži 5 x 5 m. Raziskava je potrdila zmanjšanje gostote mladovja z njegovim razvojem, ob tem pa povečanje deleža bukve. Delež zastiranja tal z mladovjem se je proti pričakovanjem zmanjšal, povečalo pa se je zastiranje z ostanki odmrlih dreves in skalami. Prehajanja jelke ter javorja v višje višinske plasti ni bilo, močno pa so se zmanjšali tudi njuni gostoti v prvem višinskem razredu, kjer zdajšnja jelova znaša 0,01 m-2, javorjeva pa 0,005 m-2. Bukev ima glede na spremembo gostot po višinskih razredih normalen razvoj. Manjšanja objedenosti z višinskim razvojem mladovja ni bilo moč z gotovostjo potrditi. V raziskavi smo merili in ocenjevali tudi različne parametre dominantnega osebka vsake ploskve. Ob zadnji meritvi je delež enojne razrasti glavnega poganjka, v nasprotju s pričakovanji, upadel, narasla pa sta deleža rogovilaste in metlaste razrasti. Delež enoosne oblike razrasti dominantnega osebka je nekoliko upadel, delež plagiotropne razrasti pa precej narasel. HD razmerje dominantnih osebkov še naprej narašča. This research took place in an old-growth forest reserve, Rajhenavski Rog, located in the Dinaric Mountains in southern Slovenia. It was the fourth measurement of tree regeneration in permanent plots located in six gaps with a 5 x 5m grid used to define the plot locations. The analysis confirmed a decline in regeneration density (competitive thinning) and an increasing proportion of beech. There was also a significant decline in regeneration cover, and an increase in the cover of dead wood and rock cover, which was against our expectations. There was no recruitment of fir and sycamore maple in different regeneration height layers, and their densities in the first regeneration layer heavily decreased over the length of the study. The density of the fir is now 0,01 m-2 and the density of sycamore maple 0,005 m-2. Beech exhibited normal development considering the density changes in regeneration layers. Even though regeneration has recruited to taller height classes over time, we could not confirm that browsing decreased. We also measured and evaluated different parameters on dominant beech stems in each plot, including tree architecture. The results show that the proportion of stems with single terminal shoots (optimal architecture), contrary to our expectations, slightly declined over time, while the share of stems with plagiotropic growth and two terminal shoots rose considerably. Finally, the height-diameter ratio of the dominant stems rose continuously over time.

Oksidativni stres je dokazano povezan s številnimi boleznimi človeka in sodeluje pri procesu staranja. Zadnje čase se zato vedno bolj preučuje delovanje antioksidantov. V sklopu magistrske naloge smo preučevali antioksidativno učinkovitost dveh komercialnih pripravkov iz ekstrakta lesa bele jelke in standardnih antioksidantov: askorbinske kisline, resveratrola in epigalokatehin-3-galata, 2,6-diterciarni butil-p-hidroksi toluena in D-α-tokoferol sukcinata pri dveh različnih koncentracijah (0,05 in 0,1 g suhega ekstrakta oz. učinkovine/L) z uporabo kvasovke Saccharomyces cerevisiae kot modelnega organizma. Antioksidativno učinkovitost antioksidantov smo preverili z merjenjem znotrajcelične oksidacije. Dokazali smo, da komercialna pripravka lesa in standardni antioksidant EG, raztopljeni v vodi, statistično značilno znižajo znotrajcelično oksidacijo kvasovke, kjer je bilo največje znižanje znotrajcelične oksidacije glede na vrednost opaženo pri EG, in sicer pri koncentraciji 0,1 g/L. V celicah kvasovke, ki so bile izpostavljene etanolnim raztopinam komercialnih pripravkov lesa v preučevanih koncentracijah ni prišlo do znižanja znotrajcelične oksidacije kvasovke. Z metodo štetja kolonij na ploščah smo preverili zaščitno vlogo predtretiranja celic kvasovk z vodnimi raztopinami komercialnih pripravkov lesa in EG v koncentraciji 0,1 g/L pred oksidativnim stresom, ki smo ga inducirali z dodatkom vodikovega peroksida. Predtretiranje celic z EG je statistično značilno povečalo kultivabilnost glede na kulturo, ki ni bila predtretirana kot tudi v primerjavi s predtretiranjem celic s pripravkoma lesa, ki pa v preučevani koncentraciji nista pokazala zaščitne vloge pred induciranim oksidativnim stresom. Oxidative stress is connected with many human diseases and also contributes to the aging process. There are many studies investigating different antioxidants and their activity. The aim of the M.sc thesis was to determine antioxidative activity of the commercial preparations from the silver fir wood extract and standard antioxidants like: ascorbic acid, resveratrol, epigalolocatechin gallate (EG), butylated hydroxytoluene (BHT), and D-α-tocopherol succinate in two different concentrations (0.05 in 0.1 g dry extract or compound/L) using yeast Saccharomyces cerevisiae as a model organism. The antioxidative activity was determined my measuring intracellular oxidation. It was determined that both commercial wood preparations and EG dissolved in water, decreased the level of yeast intracellular oxidation, where the highest decrease was observed at EG in concentration of 0.1 g/L. Ethanolic extracts of commercial wood preparations at defined concentrations did not decrease the level of oxidation in the cells. Additionally, by measuring culturability we investigated the role of pretreatment of the yeast cells the with water extracts of commercial preparations and EG (0.1 g/L) in the protection of cells against oxidative stress induced with hydrogen peroxide. Culturability of yeasts cells pre-treated with EG was higher compared to the non-treated cells as well as to commercial wood preparations, which did not show any protective role against induced oxidative stress at defined concentration.

V zadnjih desetletjih postajajo vse bolj pereča tema klimatske spremembe ter njihov vpliv na okolje in biosfero. Zelo pogoste so napovedi o dvigu globalne povprečne letne temperature ter večji pogostosti in intenzivnosti vremenskih ekstremov. To bo prav gotovo imelo opazen vpliv tako na človeško družbo, kot na vse ostale organizme ki bivajo na tem planetu. S to raziskavo smo želeli ugotoviti njihov vpliv na potencialno razširjenost (bele) jelke (Abies alba) pri nas. Za območje raziskave smo izbrali alpsko fitogeografsko regijo Slovenije ter dinarsko fitogeografsko regijo Slovenije in Hrvaške, saj je tam jelka pri nas najbolj pogosta. Že danes je opazno krčenje areala jelke na južnem območju razširjenosti zaradi vse intenzivnejših poletnih suš in vročine v Mediteranu ter širjenje areala proti severovzhodu zaradi toplejše klime in milejših zim kontinentalne Evrope. Vpliv klimatskih sprememb na potencialno razširjenost smo želeli ponazoriti s pomočjo ekološkega modeliranja. Vzeli smo prostorske podatke o razširjenosti jelke v Sloveniji in na Hrvaškem ter okoljske spremenljivke (nadmorska višina in bioklimatske spremenljivke) za današnje stanje in štiri prihodnje scenarije na podlagi štirih različnih možnih reprezentativnih koncentracij toplogrednih plinov (RCP). Te podatke smo obdelali s pomočjo GIS orodij ter nato izvedli modeliranje z modelom Mahalonobisova tipičnost (Mahalonobis) in Maksimalna entropija (Maxent), s pomočjo katerih smo želeli napovedati primernost habitata za jelko danes in v primeru vseh štirih prihodnjih scenarijev. Rezultati niso pokazali večjih sprememb v primernosti habitata v obeh regijah. Primernost habitata naj bi se nekoliko povečala, v osrednjem in zahodnem delu alpske regije najbolj ob bolj optimističnih scenarijih (RCP2.6 in RCP4.5), na Pohorju in v Dinarski regiji pa ob bolj pesimističnih scenarijih (RCP6.0 in RCP8.5). Izrazitejše izboljšanje primernosti habitata pa bodo najbrž vseeno zavrli vse intenzivnejši vremenski ekstremi (poletna suša in vročina, zimski mraz, vremenske ujme). Zaradi zavrtja vplivov Mediterana s stani gorskih barier na jugozahodnem robu obeh regij bo sprememba areala in primernosti habitata jelke najbrž bolj podobna tistim v notranjosti celine, ki predvidevajo širjenje areala in boljše uspevanje jelke zaradi toplejše klime in milejših zim, kot tistim v Mediteranu, ki predvidevajo krčenje areala zaradi vse pogostejših in intenzivnejši poletnih suš in vročine. Točnost modelov in reprezentativnost rezultatov nekoliko omejujejo groba resolucija in popačenost bioklimatskih podatkov na regionalni ravni ter različna gostota podatkov o razširjenosti jelke na obeh straneh meje. Za boljši model se je izkazal Mahalonobis, saj Maxent slabo operira s tovrstnimi tipi prostorskih podatkov. During the last few decades climate change and its influence on global environment is becoming more and more importan topic. Predictions about the rise of global average annual temperature and more and more common and intensive weather extremes are a part of everyday news. Those change will certainly have a very noticeable influence on human society and all other living organisms of our planet. We decided for this research to demonstrate their influence on potencial distribution of silver fir (Abies alba) in Slovenia and Croatia. We chose alpine phytogeogaphic region of Slovenia and dinaric phytogeogaphic region of Croatia for this research because silver fir is most common there in Slovenia and Croatia. In Southern Europe decline of silver fir due to summer droughts and heat has already been observed as well as spreading of its range towards north-east in continental Euope due to warmer climate and more and more mild winters. We studied the influence of climate change on potencial distribution of silver fir with ecological modeling. We took spatial data of silver fir distribution in Slovenia and Croatia and environmental data (altitude and bioclimatic data) for present and four diferent scenarios of representative greenhouse gas concentration pathways (RCP) for the future. We worked with this data with the help of GIS sofware and used models Mahalonobis Typicality and Maxent to predict habitat suitability for present and every future scenario by modeling. The results showed no major change of habitat suitability for both regions. Habitat suiability should slightly rise, in central and western part of Alpine region more by optimistic scenarios (RCP2.6 and RCP4.5), on Pohorje and in Dinaric region more by pessimistic scenarios (RCP6.0 and RCP8.5). More distinctive change of habitat suitability would be probably suppressed by weather extremes (summer drought and heat, cold winte periods, extreme weather phenomena). Due to suppressed mediteranean climate effect by mountain chains on the south-west border of both regions changes of spatial distribution and habitat suitability will probably be more similar to those in continental europe, which anticipate speading of fir range and better growth due to warmer climate and more mild winters, than those in southern Europe, which anticipate decline of fir range due to more and more common summer droughts and heat. Model accuracy and representativity of results are restriced by rough resolution and weak accuracy of spatial bioclimatic data on regional scale and diferent density of spatial fir distribution data for both countries. Mahalonobis turned out to be better model than Maxent for prediction operating with this kind of spatial data.

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.

Primerjali smo postopke za ocenjevanje volumna debeljadi jelke na podlagi Huberjevega, Smalianovega in Newtonovega obrazca. Podatke za primerjavo smo dobili z interpolacijo kubičnih zlepkov na podlagi merjenja posekanih dreves. Newtonov in Huberjev postopek sta bila najnatančnejša pri ocenjevanju volumnovstarih jelk (starost do 200 let, povprečni premer 59 cm). Na podlagi izračunanih volumnov smo ocenjevali volumne stoječih dreves v sklopu gozdne inventure. Slovenske Čoklove tarife (1959) so se kljub svoji preprosti zasnovi izkazale s sprejemljivo natančnostjo (povprečno odstopanje v odstotkih od povprečnega volumna < 1 %, R2=0.87). Delež pojasnjene variabilnosti volumnov dreves se je povečal za 5 % pri dvovhodnih deblovnicah in za 11 % pri triparametrskih volumenskih funkcijah. Comparisons of stem volume estimation techniques were performed based on equations of Huber, Smalian and Newton, and a cubic spline interpolation of points along the silver fir tree stems. Results indicate that Newton`s and Huber`s equations were the most accurate in determining volumes of old silver fir trees (age up to 200 years and average dbh 59 cm). The obtained tree volumes were the basis for the standing timber estimation in the forest inventory. Despite their rather simple structure, the Slovene Čokl (1959) tariff functions proved to be sufficiently accurate (average residual in percentage of the mean volume < 1%, R2=0.87). The proportion of the individualtree volume variance explained increased by 5 % for standard two-entry volume tables and by 11% for three-parameter volume functions.

Delo obravnava nekatere populacijskogenetske značilnosti jelke (Abies alba Mill.) v Sloveniji. Z analizo 10 encimskih sistemov in 16 izoencimskih lokusov so ocenjene genetska struktura, genetska raznolikost in genetska diferenciranost osmih slovenskih jelovih populacij. Na osnovi teh značilnosti avtorja jelove populacije v Sloveniji primerjata s tistimi iz nekaterih drugih delov Evrope. Preskušeni sta hipotezi o vplivu geografske dolžine in o vplivu geografske dolžine in o vplivu reakcije tal na genetsko strukturo jelovih populacij v Sloveniji.

V prispevku analiziramo strukturo in razvojne značilnosti sestojev z jelko, gospodarjenje in posek jelke po stirih rastiščnih skupinah (A-D) glede na gojitveno ekološke značilnosti jelke na podlagi podatkovnih zbirk Zavoda za gozdove Slovenije. V lesni zalogi jelke prevladuje srednje debelo (d=30-49 cm)in debelo drevje (d=50 cm in veè) (84,9 %). Najveè (45 %) debelih jelk je vdinarskih jelovjih in jelovih bukovjih (skupina B), razvojno najmlajsa je jelka v jelovjih s praprotmi in na drugih jelovih rastiščih na nekarbonatu (skupina C). Analiza debelinske strukture jelke in stevila dreves iz prve in druge izmere na stalnih vzorčnih ploskvah ter naraščanje povprečnega premera posekanih jelk v obdobju zadnjih 14 let nakazujejo staranje in regresijo jelke, ki sta izrazitejša v skupini B. Vraščanje jelke prek meritvenega praga je največje v skupini C (19,2/ha/10 let) in se statistično značilno razlikuje od drugih skupin. Najmanjšo vrast jelke ugotavljamo v skupini B (4,2/ha/10 let), jakost poseka jelke je tu najvišja (22,3 % LZ) z najvišjim povprečnim premerom posekanih jelk (42,5 cm) in 48 % sanitarne sečnje. Za aktivno ohranjanje jelke je pomembno predvsem zmanjšanje vpliva jelenjadi in skrbno ter diferencirano gojitveno ukrepanje z daljšimi parcialnimi pomladitvenimi dobami. Predlagamo tudi nekatere druge ukrepe. In the paper, we analysed the structure and developmental characteristics of forest stands with silver fir in Slovenia, the management and cut in four forest site strata, where silver fir occurs. We used databases from the Slovenia Forest Service. In growing stock (GS) of silver fir, large (dbh=30-49cm) and very large (d=50 cm and more) diameter trees account for 84.9 % at the national level. The highest share of very large diameter silver fir trees (45 %) is in Dinaric silver fir forests and silver fir-beech forests(B), the lowest in silver fir forests with fern and silver fir forests on non-carbonate ground (C). The dbh structure of GS, number of silver fir trees recorded from two subsequent measurements from permanent sampling plots,rising mean dbh of harvested silver fir trees all indicate general agingand regression of silver, which is typical of stratum B but not in all other strata. The ingrowth of silver fir in 10 years is highest in stratum C (19.2 trees/ha), the lowest in B (4.2 trees/ha). In the latter, cut intensity (22.3 % of GS), the mean dbh of harvested silver firs are highest, too. For active conservation of silver fir, reduction of the impact of large ungulates and differentiated silviculture with longer regeneration periods is of crucial importance. Some other measures are also suggested.

Structural indices are often proposed as guiding measures for increasing structural heterogeneity. However, few studies have examined the association between such indices and conventional stand attributes. The primary objectives of this study were to evaluate changes in structural heterogeneity and tree species diversity at different plot sizes and to quantify the relationships between conventional stand attributes (mean tree diameter, absolute tree density, basal area, species proportion) and structural indices in a mixed old-growth forest in Southeast Europe. Paired tests were used to identify significant changes in structural heterogeneity with increased plot area, while the relationships between stand attributes and analyzed indices (Gini, diameter differentiation, species mingling, and Shannon&rsquo, s index) were evaluated with Pearson&rsquo, s correlations. The index values of Gini, diameter differentiation, and tree species mingling were rather stable with the increase of plot size, whereas tree species diversity increased significantly with the increase of plot area from 200 m2 to 1500 m2. The measures of tree species mingling and tree species diversity were strongly associated with each other, while their association with diameter variability was weak to moderately strong. Tree species mingling index was strongly associated with the changes in tree species proportions. However, conventional stand attributes were generally not strongly correlated with the examined indices. For restoring and maintaining old-growth characteristics, forest managers may use structural indices to increase small-scale structural heterogeneity, tree species mingling, and diversity, but only as an additional set of measures, not as surrogates for conventional stand attributes.

Dolgoročno dinamiko jelovo-bukovih gozdov v Sloveniji v treh prostorsko ločenih objektih (Leskova dolina, Trnovo in Jelovica) smo proučevali s podatki, ki smo jih pridobili iz gozdnogospodarskih načrtov in gozdarskih kart. Podatkovna zbirka GIS je obsegala podatke iz obdobja po letu 1897 za Trnovo, po letu 1899 za Jelovico in po letu 1912 za Leskovo dolino. Za analizirano obdobje smo ugotovili znatne spremembe proučevanih sestojnih znakov (debelinske strukture, lesne zaloge, raznolikosti debelinske strukture in drevesne sestave). Med objekti je različna velikost in usmerjenost sprememb sestojnih znakov. Nanje vplivajo mnogi dejavniki med pomembnejšimi so prejšnja raba gozdov, vpliv velikih rastlinojedov in rastiščne razmere. The long-term dynamics of silver fir-European beech forest stands in Slovenia were studied in three geographically dislocated study areas, Leskova dolina, Trnovo and Jelovica. In the study archival forest management plans and maps for the past century were used to create the GIS database. It included the data for the period after 1897 for Trnovo study area, after 1899 for Jelovica study area, and after 1912 for Leskova dolina study area. Substantial changes in diameter structure, stand volume, tree size diversity and tree species composition were documented, significantly differing between the study areas. Found stand dynamics were underpinned by a complex array of influential factors, among which past forest use, the impact of large ungulates and site conditions stood out.

Delo obravnava nekatere populacijskogenetske značilnosti jelke (Abies alba Mill.) v Sloveniji. Z analizo 10 encimskih sistemov in 16 izoencimskih lokusov so ocenjene genetska struktura, genetska raznolikost in genetska diferenciranost osmih slovenskih jelovih populacij. Na osnovi teh značilnosti avtorja jelove populacije v Sloveniji primerjata s tistimi iz nekaterih drugih delov Evrope. Preskušeni sta hipotezi o vplivu geografske dolžine in o vplivu geografske dolžine in o vplivu reakcije tal na genetsko strukturo jelovih populacij v Sloveniji.

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.

S podatki iz ohranjenih gozdnogospodarskih načrtov in iz dveh zaporednih meritev sestojev na stalnih vzorčnih ploskvah (SVP n = 247) smo analizirali spreminjanje lesne zaloge in debelinske strukture jelke v bohorskih gozdovih (GGO Brežice, GGE Bohor), kjer prevladujejo rastišča acidofilnih bukovih ter bukovih gozdov na karbonatu. Na izbranem območju znotraj GGE Bohor (1,5 * 3,25km) smo na 51 SVP analizirali pomladek po drevesnih vrstah, višinskih razredih in objedenosti. V analiziranem obdobju (1958-2008) se je delež jelke v lesni zalogi gozdnih sestojev opazno spreminjal v zadnjih tridesetih letih se je delež jelke v skupni lesni zalogi povečal z 10,4 % na 14,1 %. Še opazneje se povečuje delež jelke med tanjšim drevjem s prsnim premerom 10 do 30 cm, saj se je v obdobju 1987-2007 povečal za šest odstotnih točk. V analiziranih gozdovih se jelka obilno pomlajuje (25,1 % celotnega števila pomladka) in uspešno prerašča v višje višinske razrede. Ugotovljena progresija jelke v bohorskih gozdovih je izjema v slovenskem prostoru, zato je objekt vreden podrobnejše raziskave vzrokov za uspešen razvoj jelke. Morebitni razlogi so lahko majhna gostota jelenjadi, rastiščne razmere in način gospodarjenja. The data from the old management plans and the last two inventories on the permanent sampling plots (PSP, n = 247) were used to analyze changes in growing stock and diameter structure of the silver fir in the Bohor forests (Forest Management Region Brežice, Forest Management Unit (FMU) Bohor) where beech forests on acid and carbonate bedrock prevail. Additionally, field surveys of regeneration on the location of 51 PSP were made in the central part of the FMU Bohor (1.5*3.25 square kilometers) in order to analyze tree species composition, height structure, and browsing damages of regeneration. Ashare of silver fir in total growing stock has been changing during the analyzed period 1958-2008 in the last thirty years the share of silver fir in total growing stock has increased from 10.4 % to 14.1 %. Even more striking is an increasing share of silver fir in small diameter trees with diameter at breast height 10-30 centimeter, which has increased by 6 percentage points in the period 1987-2007. Silver fir regeneration is abundant (25.1 % of total number of saplings) and the ingrowth of fir saplings in higher height classes is successful. The progression of the silver fir in the Bohor forests is an exception in Slovenia therefore a more detailed research of causes for successful silver fir development is worth making. Possible reasons could be low density of red deer, site conditions, and management treatments.

Namen prispevka je ugotoviti produkcijske sposobnosti jelovih (Abies alba Mill.) sestojev, opozoriti na nekatere rastne značilnosti in prikazati kakovostno strukturo jelovih dreves. V raziskavo smo zajeli 14 rastiščnih enot. Na vsaki smo postavili 5 raziskovalnih ploskev v odraslih, nerazgrajenihsestojih, kjer je jelka prevladovala. Produkcijska sposobnost rastišč se zmanjšuje z nadmorsko višino in skalovitostjo, večja pa je na konkavnih terenih in osojnih ter vzhodnih legah. V analiziranih sestojih so sejelke pomladile v 5 do 70 letih. Na veliki večini rastiščnih enot se višinski in debelinski prirastek zmanjšujeta tudi po prirastni depresiji v obdobju 1960 do 1990. Podstojne jelke so v povprečju za 10 do 40 let mlajše oddominantnih, na manj produktivnih rastiščih so razlike manjše. Sortimentna struktura jelke je ugodnejša na rastiščih (nekarbonatnih) jelovij, deloma tudina bukovih rastiščih, navzdol pa izstopajo dinarski jelovo-bukovi sestoji.Vrednost jelke je v zelo veliki meri pogojena s prsnim premerom, v majhni meri pa tudi z utesnjenostjo oziroma velikostjo krošnje, večvrhatostjo ter boniteto rastišča. The aim of this paper is to establish site productivities of Silver fir (Abiesalba Mill.) stands, to show some growth characteristics and to analyze the quality structure of Silver fir trees. The research was carried out on 14 site units. On each, 5 research plots in mature, compact stands where Silver fir dominated were set. Site productivity decreases with the altitude and stoniness while being higher on the concave sites and on the shady or east wards exposed positions. Silver firs from the analyzed stands regenerated in periods lasting 5-70 years. The height and diameter increments are still decreasing after the increment depression in years 1960-1990 on the majority of the sites. The overtopped Silver firs are 10-40 years younger than the dominant ones. The differences are lower on the less productive sites. The assortment structure of Silver fir is more favorable on Silver fir (noncarbonated) sites, partially also on beech sites, while the dinaric Silverfir-beech stands showed the worst structure. The value of the Silver firstems depends to a very large extent on the diameter at breast height, while crown size or crown isolation, forking and site productivity have little effect.

V celotni lesni zalogi gozdnih sestojev v Sloveniji se zmanjšuje delež jelke (Abies alba Mill.). Za ustrezno gojitveno in gozdnogospodarsko obravnavo gozdnih sestojev z jelko je pomembno poznavanje prirastoslovnih značilnosti. V raziskavi smo se omejili na debelinsko priraščanje jelke, ki smo ga analizirali s podatki s stalnih vzorčnih ploskev za 73 gozdnogospodarskih enot(N = 42.265 jelk). Povprečni letni debelinski prirastek jelke v izbranih enotah je znašal 3,43 0,25 mm. Variabilnost debelinskega priraščanja jelk jebila izrazita (KV = 75 %). Multivariatna analiza je pokazala značilen vpliv socialnega razreda drevesa, sestojne temeljnice, deleža bukve v sestoju, razvojne faze in rastiščne skupine na debelinski prirastek jelke. Izračunani so bili nekateri parametri modela priraščanja jelk in jelovih sestojev ob različnih sestojnih gostotah. V razpravi presojamo uporabnost in pomen rezultatov za gospodarjenje z jelko. Proportion of silver fir (Abies alba Mill.) in the total growing stock of forest stands in Slovenia is decreasing. Therefore the knowledge on growth characteristics of silver fir is crucial for its appropriate treatment in forest management. Diameter growth of silver fir was analyzed with the data from permanent sampling plots in 73 forest management units (42,265 silver firs). Mean annual diameter increment in the study area was 3.43 0.25 mm its variability was significant (CV = 75 %). Multivariate analysis showed significant influence of social class, forest stand basal area, proportion of European beech (Fagus sylvatica L.) in the forest stand, the developmental phase and forest site stratum on the diameter increment of silver fir. A silver fir forest stand growth model with regard to various stand densities was calculated. In the discussion, the applicability and importance of the results for future forest management with silver fir were evaluated.

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.

Summary Studies of old-growth forests are becoming increasingly important for the improvement of silviculture and for understanding environmental changes. However, in Europe such forests are rare, fragmented and influenced by millennia of human activity. Comparative studies of old-growth forests across Europe are needed to improve knowledge on how direct and indirect anthropogenic factors influence their structure. We analysed structural dynamics in 15 silver fir-beech-Norway spruce old-growth forests in Slovenia, Croatia, Slovakia and Bosnia-Herzegovina. Changes in diameter distributions, stand parameters and regeneration were analysed at intervals of 6–116 years. Most diameter growth at breast height (d.b.h.) distributions approximated a rotated sigmoid shape, which could be explained by differences in growth and mortality rates with respect to d.b.h. class and by disturbance history. Our results suggest that different disturbance types are likely to cause different changes in d.b.h. distributions. For example, overbrowsing, canopy dieback of silver fir and windthrow decreased the density of small, intermediate and large-diameter silver fir, respectively. The slopes of the fitted diameter distribution curves were steeper for beech than for silver fir, which could be explained by their different life strategies. Despite disturbances, growing stocks remained stable over the long term. A synchronous silver fir decline was confirmed. It was more pronounced in Slovenia and Slovakia, both of which experienced more SO2 pollution and had higher ungulate densities. The silver fir sapling stage was often totally absent in both countries. Our results suggest that anthropogenic disturbances, especially air pollution and overbrowsing (resulting from human-induced increases in deer density), significantly influenced the coexistence of silver fir and beech; asynchronous, patchy changes in species mixture have been replaced by large-scale synchronous changes.