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Povzetek: Understanding competition between trees is essential for sustainable forest management as interactions between trees in uneven-aged mixed forests play a key role in growth dynamics. This study investigated nine competition indices (CIs) for their suitability to model the effects of neighboring trees on silver fir (Abies alba) growth in Dinaric silver fir-European beech (Fagus sylvatica) forests. Although numerous competition indices have been developed, there is still limited consensus on their applicability in different forest types, especially in mature, structurally complex forest stands. The indices were evaluated using the adjusted coefficient of determination in a linear model wherein the volume growth of the last five years for 60 dominant silver fir trees was modeled as a function of tree volume and competition index. The results demonstrated that distance-dependent indices (e.g., the Hegyi height-distance competition and Rouvinen-Kuuluvainen diameter-distance competition indices), which consider the distance to competitors and their size, perform better than distance-independent indices. Using the optimization procedure in calculating the competition indices, only neighboring trees at a distance of up to 26-fold the diameter at breast height (DBH) of the selected tree (optimal search radius) and with a DBH of at least 20% of that of the target tree (optimal DBH) were considered competitors. Therefore, competition significantly influences the growth of dominant silver firs even in older age classes. The model based solely on tree volume explained 32.5% of the variability in volume growth, while the model that accounted for competition explained 64%. Optimizing the optimal search radius had a greater impact on model performance than optimizing the DBH threshold. This emphasizes the importance of balancing stand density and competition in silvicultural practice.
Ključne besede: sustainable forest management, Dinaric silver fir-European beech forests, Competition indices, CIs, optimal search distance, optimal diameter at breast height, DBH
Objavljeno v DiRROS: 05.06.2025; Ogledov: 441; Prenosov: 260
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Povzetek: The role of the urban common (i.e. shared space and resources) in sustainable provisioning of goods and services to city dwellers is discussed in this paper. Focusing on tree-based green infrastructure, the study scope includes three categories of provisioning (woody biomass, food/fibre, and non-timber forest products, i.e. NTFPs), alongside three categories of supporting services (fresh water replenishment, soil nutrient restoration, building preservation). As a first step, prospects of utilizing the urban common as facilitator of nature-based solution to the earmarked provisioning services are evaluated through dedicated literature survey and expert elicitation on perceived impact of environmental change triggers and management interventions (planning and/or governance). This is followed by a structured review of the state of affairs in four European cities (London, Amsterdam, Sofia, Ljubljana), representing different macro-geographical regions with distinct socio-economic drivers in managing these provisioning services. The pan-European expert elicitation exercise noted active management of the urban common as positively impacting on the performance of the majority of provisioning services, while environmental change impacts were found to be overriding and adversely influencing the provisioning of material resources (mainly NTFPs and woody biomass). The four-city case study highlighted some regional peculiarities in connecting the city dwellers to the urban common and identified the need to overcome socio-cultural barriers for enhancing pan-European best practice sharing in the management of goods and services provisioning. This is deemed essential to pave way for an emerging perspective on sustainable utilization of the urban common as an enabler for nature-based solution, making it fit for purpose in meeting the astronomical demands of future urban living.
Ključne besede: urban forests, nature-based goods, forest services
Objavljeno v DiRROS: 18.04.2025; Ogledov: 508; Prenosov: 149
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Ključne besede: Close-to-nature, forest sustainable management, climate changes, forests, handbook
Objavljeno v DiRROS: 19.02.2025; Ogledov: 547; Prenosov: 469
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Povzetek: Pred uporabo natančnejših fizikalno-kemijskih meritev (analitične meritve vsebnosti določenih elementov v padavinah in foliarnih vzorcih) za oceno poškodovanosti gozdov oz. odziv gozdov na onesnaženost so se v okviru programa ICP Forests uveljavile predvsem posredne oblike spremljanja vplivov onesnaženosti na gozdne ekosisteme oz. ocene posledic onesnažil na drevesa. Eden od pomembnejših kazalnikov je ocena osutosti krošnje, ki predstavlja okularno ocenjen delež manjkajočih asimilacijskih organov (listov oz. iglic) v primerjavi z normalno vitalnim drevesom enakega socialnega položaja, enake drevesne vrste in z enakega rastišča. Ocenjujemo ga na 5 % natančno. Za poškodovano velja drevo, katerega osutost drevesne krošnje je večja od 25 % (manjka ji vsaj četrtina listnega aparata). V prispevku so predstavljeni rezultati spremljanja stanja osutosti na desetih ploskvah intenzivnega monitoringa (ICP Forests) po letu 2003. V zadnjih letih so bile najbolj osute krošnje dreves na ploskvah Fondek (bukev), Gropajski bori (črni bor), Gorica (bukev) in Lontovž (bukev). Na vseh štirih ploskvah, razen Gorice, se je v zadnjem obdobju povprečna osutost povečevala. Ploskev Gropajski bori je v prehodnem obdobju, kjer umetno nasajeni črni bor počasi nadomeščajo avtohtoni listavci. Med drevesnimi vrstami so v zadnjem obdobju med bolj osutimi predvsem črni gaber in črni bor na ploskvi Gropajski bori ter dob na ploskvah Krakovski gozd in Murska šuma ter tudi bukev na ploskvi Fondek. Od leta 2014 se povprečna osutost postopno slabša na več kot polovici ploskev, predvsem na ploskvah, kjer stari sestoj nadomešča mladovje. Predvidevamo, da je v letu 2022 na poslabšanje stanja v največji meri vplivala poletna suša s pripadajočimi dejavniki.
Ključne besede: stanje gozdov, osutost dreves, intenzivni monitoring, ICP Forests, iglavci, listavci
Objavljeno v DiRROS: 06.12.2024; Ogledov: 759; Prenosov: 239
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Povzetek: Bryophytes respond to a variety of environmental factors, including tree species composition and geological conditions, which are influenced by both natural and anthropogenic factors. Bryophytes growing on a variety of substrates were identified in ICP Forests monitoring plots in a wide range of close-to-nature managed forests, from lowland to high mountain areas in Slovenia. Based on data on tree layer composition (broadleaves vs. conifers) and on bedrock and soil type (calcareous vs. siliceous bedrock), all study plots were classified into five groups representing forest types. Different ordination analyses and statistical tests were used to represent differences between forest types in bryophyte composition, richness and functional traits. Almost 200 bryophyte species were identified in managed forests, with the most common being Hypnum cupressiforme, Brachytheciastrum velutinum and Polytrichum formosum. Bryophyte species composition varied considerably along the tree species composition and edaphic gradients represented by the selected forest types. Bryophyte species richness was significantly higher on calcareous bedrock than on siliceous bedrock. The higher occurrence of rocks on the ground surface may significantly increase the availability of various microhabitats for bryophytes. Bedrock had a significant influence on the functional diversity and composition of bryophytes, while tree species composition had less influence. Bedrock and tree species composition are important drivers of bryophyte species composition and diversity at taxonomic and functional trait levels. The high diversity of bryophyte species in Slovenian forests can also be attributed to close-to-nature and sustainable forest management practices that preserve favourable microclimatic conditions in forest stands and maintain diverse substrates.
Ključne besede: mosses, species richness, functional diversity, site conditions, overstory, sustainable managed forests, European temperate zone
Objavljeno v DiRROS: 31.07.2024; Ogledov: 929; Prenosov: 793
Celotno besedilo (6,99 MB)
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