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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.

Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to account for the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the implementation of a forest management module containing even-age and clear-cut and uneven-age and continuous-cover management alternatives in the dynamic vegetation model LPJ-GUESS. Different age and species structure initialisation strategies and harvest alternatives are introduced. The model is applied at stand and European scales. Different management alternatives are applied in simulations of European beech (Fagus sylvaticus) and Norway spruce (Picea abies) even-aged monoculture stands in central Europe and evaluated against above-ground standing stem volume and harvested volume data from long-term experimental plots. At the European scale, an automated thinning and clear-cut strategy is applied. Modelled carbon stocks and fluxes are evaluated against reported data at the continent and country levels. Including wood harvest in regrowth forests increases the simulated total European carbon sink by 32%% in 1991%2015 and improves the fit to the reported European carbon sink, growing stock, and net annual increment (NAI). Growing stock (156%m3%ha%1) and NAI (5.4%m3%ha1%yr1) densities in 2010 are close to reported values, while the carbon sink density in 2000%2007 (0.085%kg%C%m%2%yr1) equates to 63%% of reported values, most likely reflecting uncertainties in carbon fluxes from soil given the unaccounted for forest land-use history in the simulations. The fit of modelled and reported values for individual European countries varies, but NAI is generally closer to reported values when including wood harvest in simulations.

Global forests are the main component of the land carbon sink, which acts as a partial buffer to CO2 emissions into the atmosphere. Dynamic vegetation models offer an approach to projecting the development of forest carbon sink capacity in a future climate. Forest management capabilities are important to include in dynamic vegetation models to account for the effects of age and species structure and wood harvest on carbon stocks and carbon storage potential. This article describes the implementation of a forest management module containing even-age and clear-cut and uneven-age and continuous-cover management alternatives in the dynamic vegetation model LPJ-GUESS. Different age and species structure initialisation strategies and harvest alternatives are introduced. The model is applied at stand and European scales. Different management alternatives are applied in simulations of European beech (Fagus sylvaticus) and Norway spruce (Picea abies) even-aged monoculture stands in central Europe and evaluated against above-ground standing stem volume and harvested volume data from long-term experimental plots. At the European scale, an automated thinning and clear-cut strategy is applied. Modelled carbon stocks and fluxes are evaluated against reported data at the continent and country levels. Including wood harvest in regrowth forests increases the simulated total European carbon sink by 32 % in 1991–2015 and improves the fit to the reported European carbon sink, growing stock, and net annual increment (NAI). Growing stock (156 m3 ha−1) and NAI (5.4 m3 ha1 yr1) densities in 2010 are close to reported values, while the carbon sink density in 2000–2007 (0.085 kg C m−2 yr1) equates to 63 % of reported values, most likely reflecting uncertainties in carbon fluxes from soil given the unaccounted for forest land-use history in the simulations. The fit of modelled and reported values for individual European countries varies, but NAI is generally closer to reported values when including wood harvest in simulations.

We studied conceptual and financial options for implementing a forest property plan (FPP) into the forest planning system. By employing multiple quantitative surveys of Slovenian non-industrial private forest owners, we 1) examined how owners (n = 754) conceptualize forest management and resource-efficiency using structural equation modeling 2) studied owners% (n = 374) decision-making styles using a probabilistic approach while controlling for model-reality consistency and acquiescence bias to account for uncertainties in owner classification 3) explored owner% (n = 510) willingness-to-pay (WTP) for the FPP using the Heckit econometric model and estimated financial implications for publicly funded forest planning and 4) analyzed satisfaction with the FPP using semi-structured interviews with the owners (n=11) for which the FPP prototypes have been prepared in the past two decades. We found that 1) owners underuse forest resources not because they object to harvesting, but mostly because of biophysical constraints in the environment 2) multiobjective owners who consider mainly the extractive value of forests are prime candidates for the FPP 3) owners are willing to pay for the FPP, and the cost-sharing could significantly reduce public budget expenditures for forest planning and 4) owners were mostly unsatisfied with the FPP prototypes because of insufficient consideration of their demands. We conclude that owners support the FPP conceptually and financially. Further steps in the implementation of the FPP into practice should take into account the diversity of costumer segments and uncertainty associated with the survey-based research. Proučevali smo konceptualne in finančne možnosti za uvedbo načrta za zasebno gozdno posest (NGP) v zasnovo gozdarskega načrtovanja v Sloveniji. Na podlagi v letih 2009 % 2015 izvedenih osebno vodenih in telefonskih anketiranj lastnikov zasebnih gozdov smo 1) s pomočjo strukturnega modeliranja proučevali, kako lastniki (n = 754) razumejo gospodarjenje z gozdovi in gospodarnost 2) proučevali načine njihovega odločanja (n = 374) pri upravljanju posesti uporabljajoč inovativen verjetnostni pristop ter dopolnjen postopek za zaznavo in odpravo sistematične napake v odgovorih zaradi odzivnih slogov anketirancev 3) s pomočjo Heckmanovega ekonometričnega modela analizirali pripravljenost lastnikov (n = 510) za plačilo za NGP in vplivne dejavnike 4) analizirali zadovoljstvo lastnikov (n = 11) s testnimi NGP. Ugotovili smo: 1) da lastniki ne nasprotujejo učinkovitejšemu gospodarjenju, saj med njihovim razumevanjem gospodarjenja in razlogi za negospodarjenje ni znatnih korelacij 2) tisti z več cilji gospodarjenja, ki se odločajo predsem glede na uporabno vrednost gozda, so možni kandidati za NGP 3) da so lastniki pripravljeni plačati za NGP, soudeležba pri plačilu lahko znatno zmanjša javne izdatke za gozdarsko načrtovanje 4) da so bile slabosti testnih NGP prepodrobnost, neprilogodljivost in nezadostno upoštevanje ciljev lastnikov. Zaključujemo, da lastniki podpirajo NGP konceptualno in finančno. V priporočilih opozarjamo na raznolikost lastnikov in potrebo po sodobnih pristopih, ki upoštevajo negotovost pri proučevanju lastnikov in načrtovanju.

We analyzed the characteristics of timber harvesting in private forests of Slovenia during the 1995-2014 period. The survey included forest sub%compartments that had been completely privately owned in the studied period (n = 16,234). With the multiple linear regression models we analyzed the influence of 9 natural, 4 forest%management and 3 socioeconomic variables on the amount of annual felling per hectare and the medium felled tree. We found that with the increase of the size of plots and forest property timber harvesting is increasing. Harvesting was positively influenced by the share of spruce in the growing stock, site productivity, distance to the forest edge, the openness and the share of beech in the growing stock. Harvesting was negatively influenced by inclination, distance to road and settlements, number of (co)owners, the share of spruce in the potential natural vegetation and the proportion of succession stages. The medium felled tree was positively influenced by site productivity, and most negatively by distance to the road. Analizirali smo posek v zasebnih gozdovih Slovenije v obdobju 1995-2014. V raziskavo smo vključili odseke, ki so v popolni zasebni lasti (n = 16.234). Z multiplo linearno regresijo smo analizirali vpliv devetih naravnih, štirih gozdnogospodarskih in treh socioekonomskih spremenljivk na letni hektarski posek in srednje posekano drevo. Ugotovili smo, da z naraščanjem velikosti parcele in posesti narašča tudi povprečni letni posek, medtem ko se z večanjem števila (so)lastnikov v odseku, naklonom, oddaljenostjo od ceste in oddaljenostjo od naselja, potencialnim deležem smreke v odseku in deležem sukcesijskih stadijev v odseku posek zmanjšuje. Na višino poseka pozitivno vplivajo še: delež smreke v odseku, potencialna produkcijska sposobnost rastišča, razdalja od centroida odseka do najbližjega gozdnega roba, odprtost in delež bukve v odseku. Na srednje odkazano drevo najbolj pozitivno vpliva potencialna produkcijska sposobnost rastišča, najbolj negativno pa oddaljenost od ceste.

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.