Search

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.

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.

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.

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.

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.

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.

Leta 2007 smo ponovili izmero na raziskovalni ploskvi 92 v jelovo bukovem sestoju na Menišiji, veliki 2 ha. Na podlagi podatkov o zaporednih merjenjih dreves smo ocenili razvoj gozdnega sestoja. Izmerili smo premere dreves, višine jelk ter popisali njihove kakovostne znake. Analizirali smo spremembe drevesne sestave, spremembe frekvenčnih porazdelitev dreves po debelinskih stopnjah, ocenili razvoj višin in razlike v sestojnih višinskih krivuljah, spremembe lesnih zalog ter osutosti krošenj jelke. Osutost krošnje ima močan vpliv na debelinsko rast jelke, stopnje osutosti pa se razlikujejo po slojih. In 2007 we have repeated the measurement of trees on a research plot in silverfir and beech stand in Menišija, which is 2 hectares in size. We have made an evaluation of the development of the forest stand on the basis of dataon succesive measurement. We have measured diameters of trees and heights of silver firs, and made an assessment of their quality signs. We made an analisys of the tree species structure, changes of frequency distribution of trees by diameter distribution, height distribution, growing stock, state of silver-firs crown. The tree crowns needle loss has major influence on the intensity of the diameter increment and degrees of tree crowns needle loss differ according to vertical stand layer.

V gozdnogospodarskem območju Kočevje so v obdobju 1970-2000 zgradili 152 gozdnih ograj, ki so namenjene zaščiti pomladka in mladovja pred velikimi rastlinojedi in preučevanju vpliva populacij jelenjadi in srnjadi na razvoj rastlinja. Poprečna velikost ograjene površine je 0,71 ha. Z vzorčenjem na transektu (N=42 ploskev, 4x4 m) v raziskovalnem objektu Trnovec smo podrobno raziskali sestavo in strukturo pomladka in drugega rastlinja v zeliščni in grmovni plasti na ograjeni in neograjeni površini. Analizo rastlinja smo dopolnili s tremi fitocenološkimi popisi. Pri parni primerjavi smo ugotovili značilne razlike v višinski strukturi in sestavi pomladka. Na ograjeni površini smo evidentirali več mladic, ki so višje od 50 cm, in znatno večje število mladic jelke (Abies alba), javorja (Acer pseudoplatanus), bresta (Ulmus glabra) in drugih minoritetnih drevesih vrst. Značilne so tudi razlike v sestavi in obilju zelnatih rastlin. Ob izključitvi vpliva jelenjadi in srnjadi poteka naravna obnova povsem nemoteno. In the period 1970-2000, 152 fenced-in areas were built in the Kočevje Forest Management Region with an aim to protect tree seedlings and saplings from ungulatesć activity and to monitor the influence of roe and red deer on natural regeneration. The average surface area of fenced areas is 0.71 ha. Using the pair comparison technique (fenced vs. unfenced areas), the structureand the composition of the natural regeneration of tree species as well as complete shrub and herb vegetation were analysed in the research site Trnovec. Furthermore, the vegetation was investigated using the Braun-Blanquetmethod. The research results show significant differences between fenced and unfenced areas, both in tree species composition and in theheight structure of the sapling community. In fenced areas the total numberof saplings taller than 50 cm is higher and an increase is also evident in the number of saplings of silver fir Abies alba, sycamore Acer pseudoplatanus, elm Ulmus glabra and other minor tree species. There are also significant differences in species composition and in the abundance of plant species in the herb layer. The results show that natural regeneration of Dinaric fir-beech forests is successful, provided the influence of ungulates is excluded.

Leta 2007 smo ponovili izmero dreves na 2 ha veliki raziskovalni ploskvi na Mašunu. Z analizo podatkov smo ocenili, da se je zgradba sestoja v 56 letih močno spremenila, podobno kot v jelovo-bukovih gozdovih, v katerih so nekdaj prebiralno gospodarili. Analizirali smo spremembe vrstne sestave, porazdelitev dreves po debelinskih stopnjah, ocenilisestojne višine in spremembe lesnih zalog. Delež jelke se je od leta 1973 do danes zmanjšal, medtem ko se je znatno povečal delež bukve. Ocenili smo, da na debelinski prirastek smrek in jelk vpliva osutost njihovih krošenj. In 2007 we have repeated the measurement of trees on the 2 ha research plot insilver fir and beech stand on Mašun. On the basis of data on succesive measurement in the last 56 years it was estimated that the structure of foreststand has changed similarly as in most silver fir and beech forests in which selection cutting was practised. We made an analisys of the tree speciesstructure, changes of diameter distribution of trees, stand height and changes in growing stock structure. The proportion of silver fir spruce has declined after the year 1973, while the share of beech on the research plot has increased. Defoliation of spruce and silver fir crowns have had an influence on the intensity of the diameter increment.

In the period 1970-2000, 152 fenced-in areas were built in the Kočevje Forest Management Region with an aim to protect tree seedlings and saplings from ungulatesć activity and to monitor the influence of roe and red deer on natural regeneration. The average surface area of fenced areas is 0.71 ha. Using the pair comparison technique (fenced vs. unfenced areas), the structureand the composition of the natural regeneration of tree species as well as complete shrub and herb vegetation were analysed in the research site Trnovec. Furthermore, the vegetation was investigated using the Braun-Blanquetmethod. The research results show significant differences between fenced and unfenced areas, both in tree species composition and in theheight structure of the sapling community. In fenced areas the total numberof saplings taller than 50 cm is higher and an increase is also evident in the number of saplings of silver fir Abies alba, sycamore Acer pseudoplatanus, elm Ulmus glabra and other minor tree species. There are also significant differences in species composition and in the abundance of plant species in the herb layer. The results show that natural regeneration of Dinaric fir-beech forests is successful, provided the influence of ungulates is excluded. V gozdnogospodarskem območju Kočevje so v obdobju 1970-2000 zgradili 152 gozdnih ograj, ki so namenjene zaščiti pomladka in mladovja pred velikimi rastlinojedi in preučevanju vpliva populacij jelenjadi in srnjadi na razvoj rastlinja. Poprečna velikost ograjene površine je 0,71 ha. Z vzorčenjem na transektu (N=42 ploskev, 4x4 m) v raziskovalnem objektu Trnovec smo podrobno raziskali sestavo in strukturo pomladka in drugega rastlinja v zeliščni in grmovni plasti na ograjeni in neograjeni površini. Analizo rastlinja smo dopolnili s tremi fitocenološkimi popisi. Pri parni primerjavi smo ugotovili značilne razlike v višinski strukturi in sestavi pomladka. Na ograjeni površini smo evidentirali več mladic, ki so višje od 50 cm, in znatno večje število mladic jelke (Abies alba), javorja (Acer pseudoplatanus), bresta (Ulmus glabra) in drugih minoritetnih drevesih vrst. Značilne so tudi razlike v sestavi in obilju zelnatih rastlin. Ob izključitvi vpliva jelenjadi in srnjadi poteka naravna obnova povsem nemoteno.