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Povzetek: Background and purpose: The objectives of our study were to identify invasive alien plant species (IAS) in the main Natura 2000 forest habitat types (FHT) along the Mura River in Slovenia, and to estimate their abundance and cover. The aim of our study was to find out a) Which IAS appear in the research forests? b) What is their frequency and cover percentage? c) Whether individual IAS prosper better in some FHT than others? d) What is the correlation between the cover of IAS and the tree layer cover? Materials and methods: We analysed the fidelity of invasive plant species to individual FHT. The studied FHTs along the Mura River were the following: 91E0* (Alluvial forests with Alnus glutinosa and Fraxinus excelsior), 91F0 (Riparian mixed forests of Quercus robur, Ulmus laevis and Ulmus minor, Fraxinus excelsior or Fraxinus angustifolia, along the great rivers) and 91L0 (Illyrian oak-hornbeam forests). Two forest areas of about 600 ha were studied in total. With the intention to calculate number and cover of IAS some statistical analysis was made. In addition, correlations between the abundances of the most present IAS and cover of upper tree layer were carried out. Results: In total, 15 IAS were recorded in studied FHTs. Some species, like Robinia pseudoacacia, Impatiens glandulifera, I. parviflora, Fallopia japonica (incl. F. x bohemica), Erigeron annuus, Ambrosia artemisiifolia, Amorpha fruticosa, Conyza canadensis and Juncus tenuis occur only in one or two FHTs, while some species can be found in all studied FHTs (e.g. Solidago sp.). We found out that the most threatened forests are those with prevailing Salix alba, Alnus glutinosa, Fraxinus angustifolia and Ulmus laevis tree species. Those are the forests of FHT 91E0 which have less dense tree canopies, grow closest to the river and on the wettest sites. We found a statistically significant higher number and cover of IAS in the FHT 91E0 and the lowest number and cover in FHT 91L0. Conclusions: Alluvial forests with Alnus glutinosa and Fraxinus excelsior (FHT 91E0) along the Mura River are most prone to invasion of IAS. The increasing presence of IAS in the study areas seriously affects natural regeneration, stability, and continuity of floodplain forests in all other FHTs in the study area. At the same time the amount of IAS in these forests also depends on management measures and their intensities which accelerate light availability. Some measures and guidelines for managing of these forests with the purpose of reducing IAS impacts are suggested in this study.
Ključne besede: non-native plants, riparian vegetation, habitat types, conservation management, forest management
Objavljeno v DiRROS: 16.04.2018; Ogledov: 2867; Prenosov: 1516
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Povzetek: Economic efficiency is one of the many essential demands regarding the technical management of windstorms. The main goal of this paper is to analyze a hypothetical scenario in which a forest owner works independently on windstorm restoration, using his own equipment and work power. Managing windstorm damage is a difficult and dangerous task, although a potentially lucrative endeavour as our investigation shows. A windstorm represents an opportunity for instant profit for forest owners who are independent of regular forest income. Economic damage is greater and longer lasting for owners with large forest properties and for farm households, which depend on regular forest income. We compared two potential scenarios in a wind-damaged area within the 2000-2010 forestry management period. First, we include a hypothetical scenario in which the windstorm did not occur. An inventory of regular thinning as well as simulation of future events based on past dynamics was done. We also performed a second scenario in which we assumed that private owners carry out windstorm restoration alone, although in reality felling has been carried out with short-wood technology (mechanized cutting). The results section presents the possibilities to attain reasonably high yield by dealing with the consequences of a minor windstorm.
Ključne besede: cost analysis, production effects, scenarios, windstorm, storm damage, forest
Objavljeno v DiRROS: 12.07.2017; Ogledov: 3879; Prenosov: 1821
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Povzetek: The research of wood fuel trade is market management oriented at household level. We devoted our attention to determine the key questions, market segmentation and market potentials. 909 households, which took part in the questionnaire and received financial support to purchase a wood biomass boilerfrom 2003 until 2006, represented our data source. The analysed pattern of questionnaired households indicates a vast unrealized developmental potential at placing additional quantities of chunkwood and forest chips on the market. Own forests still represent the most important heating source in households. Switching to wood biomass heating is practiced particularly by fuel oil consumers. Since the consumer has been placed into the centre of our research, we present some fundamental findings on product making and product development, its price, sale, promotion and management control. Our findings indicate that right business decisions and the ability to adjust to the marketfluctuation enable us good developmental possibilities.
Ključne besede: wood biomass, wood fuel trade, households, market management, chunkwood, forest chips, pellets, Slovenia
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4325; Prenosov: 1937
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Povzetek: We analysed the characteristics of silver fir (Abies alba Mill.) occurrence and distribution in Slovenia using databases of the Slovenian Forest Service (SFS). Silver fir is the third most widely distributed tree species in Slovenia, occurring in approximately 40 % of total forest area, but abundantly in less than 10 %. Its share in total growing stock varies between separate forest management regions. It is more abundant in the Dinaric and part of the Pre-alpine phytogeographic regions. The highest share in total growing stock reaches at altitudes between 800 m and 1000 m above sea level, forests with silver fir cover the most extensive surface in the altitude belt from 1000 to 1200 m. Silver fir occurs abundantly in 11 syntaxes. Between them, silver fir-beech forests (Abieti-Fagetum dinaricum TREG. 57, syn.: Omphalodo-Fagetum (TREG.57 corr. PUNC.80) MAR et al. 93) strongly prevail, followed by fir forests with fern (Dryopterido-Abietetum KOŠ.65, syn.: Galio rotundifolii-Abietetum BARTSCH.40). Silver fir diameter distribution considerably varies between separate forest management regions. The regions with the highest share of silver fir (Postojna, Kočevje) dominate also in having large diameter silver fir trees, whereas in other regions (e.g. Nazarje, Kranj, Maribor) small diameter silver fir trees are prevalent. Ddevelopmental stage structure shows that in forest stands with silver fir there is a higher share of timber phase, stands in regeneration, youth stands and selective forests. Considering regeneration we can conclude, that more intensive decreasing trend in silver fir share is expected in the Ddinaric phytogeographic region than in northern parts of Slovenia. Successful regeneration due to lower red deer population and balanced stem diameter structure with higher proportion of small diameter trees promise easier conservation of silver fir in northern parts.
Ključne besede: forest stand structure, forest vegetation, altitude, Slovenia
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4366; Prenosov: 1744
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Povzetek: Zaradi vetroloma je leta 1983 v pragozdnem ostanku Ravna gora na Gorjancih na bukovem rastišču (Cardamini savensi-Fagetum) nastala 5,17 ha velika vrzel. Dejstvo, da je izsledkov o pomlajevanju po velikopovršinskih motnjah v pragozdovih malo, nas je vodilo k temu, da smo leta 2000 analizirali stanje indinamiko pomlajevanja vrzeli. Na treh različnih delih vrzeli smo postavili 15 raziskovalnih ploskev z dimenzijami 15 x 15 metrov, znotraj katerih smo analizirali zmes, razrast dreves, sestojno stanje po IUFRO klasifikaciji, pomladek in grobe lesne ostanke. Posebej nas je zanimalo razmerje med bukvijo (Fagus sylvatica L.) in gorskim javorjem (Acer pseudoplatanus L.). Slednjega je največ na sredini vrzeli. Pod sestojem, ki je zapolnil vrzel, je razvit pomladek bukve in javorja, ki je najgostejši na spodnjem (severnem) delu vrzeli. V pomladku prevladuje bukev. Ugotovili smo, da so bile razmere, ki so se izoblikovale po vetrolomu, bistveno drugačne od tipičnega goloseka. Predstavili smo tudi uporabne izsledke za gospodarjenje v gozdovih na podobnihrastiščih.Special attention is given to the gap, which was created in the virgin forest remnant Ravna gora in 1983 by wind throw. The gap in the optimal phase of almost pure beech and on beech site (Cardamini savensi-Fagetum) was 5.17 ha large. In 2000, owing to a lack of investigations in such conditions, we started to research the development patterns of natural regeneration within the gap. 15 sample plots (15 x 15 m) in three different positions within the gap were established. We analysed tree species mixture, architecture, stand structure according to IUFRO classification, advanced regeneration density andcoarse woody debris.The reserach concentrated in particular on the variability of beech (Fagus sylvatica L.) and sycamore (Acer pseudoplatanus L.) mixture in regard to theposition within the gap. It was found out that sycamore was more abundant than beech in the center of the gap. The advanced regeneration density of beech was much higher than sycamore's, and both species were more abundant in the northern part of the gap. The results suggest that the ecological conditions after the wind throw were different when compared to a clear-cut area of similar size. Useful results for managed forests on similar sites are also presented.
Ključne besede: pragozd, Ravna gora, vrzel, mladje, vetrolom, naravna obnova, Fagus sylvatica, Acer pseudoplatanus, virgin forest, gap, wind throw, natural regeneration
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4570; Prenosov: 2091
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