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Povzetek: Wood density and radial wood increment were examined in trees of pubescent oak (Quercus pubescens Willd.) and black pine (Pinus nigra Arnold., subsp. nigra) in relation to stand mixture and underlying bedrock. Trees of both species from pure and mixed stands were sampled across two types of bedrock, limestone and flysch. Trees from each species were similar in age. Wood density was estimated in standing trees using resistance drilling and increment cores were taken from a smaller subsample of trees of both species. Tree-ring, earlywood and latewood widths were measured and compared to radial profiles of wood density. The influence of stand mixture, diameter at breast height and bedrock on wood density was examined using a Bayesian general linear model. Wood density was significantly higher in pubescent oak than in black pine. Stand mixture was found to affect wood density positively, although the magnitude of the effect was relatively small when compared to other influencing factors also included in the current study. The effect of diameter on wood density was positive on both bedrocks in pubescent oak and negative or neutral in black pine. The size of the effect varied by bedrock and species. On flysch bedrock, the influence of diameter on wood density was stronger than it was on limestone. These indirect bedrock effects on wood density are probably a result of different soil fertility rather than the bedrock itself. There was a notable difference in radial wood increment in both species across the two bedrocks, whereas the differences in densities were smaller. Higher wood densities found on flysch in the subsample of pubescent oaks are likely an effect of higher proportions of latewood, while the opposite trend was observed in black pine. Higher wood density was found on limestone in black pine despite higher latewood percentages on flysch. In the context of forest management, the species composition of the naturally occurring mixtures in the sub-Mediterranean region should be adjusted slightly to favor pubescent oak, since it is a climax species and will bind more carbon for longer than black pine due to higher wood densities. Future forest management should also promote the overall development of pubescent oak trees in sub-Mediterranean stands. The results are especially important in the European context, because the share of sub-Mediterranean stands is expected to rise with global warming.
Ključne besede: Karst, wood structure, resistograph, resistance drilling, Quercus pubescens, Pinus nigra, limestone, flysch
Objavljeno v DiRROS: 14.01.2021; Ogledov: 1117; Prenosov: 382
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Povzetek: In the presented research, we studied the forest edge structure of urban and peri-urban forests on the outskirts of Ljubljana (Slovenia) consisting of a number of patches covering the collective surface of 1884 ha. They differ from each other according to the degree of fragmentation and by the share of the interior forest area. On the basis of LiDAR data, we conducted an analysis of the edges of the persistent forest patches and estimated them with regard to the land use they bordered on. The horizontal estimation of forest edges and the changes of forest edges, in the last decades, were estimated using digital orthophoto images of cyclic aerial surveys of Slovenia, from 1975 to 2018. The data, provided by LiDAR, were used to obtain an accurate estimate of forest edges and the metrics of their vertical canopy structure. On the basis of the canopy height model (CHM), we determined the height classes, the heights of the tallest trees, and indices of canopy height diversity (CHD) as variables subjected to a k-means cluster analysis. To determine the forest edge and trees stability, their heights and diameters at breast height (DBH) were measured and their canopy length and h/d (height/diameter) dimension ratios were estimated. In the study area of the Golovec forest patch, more than half of the forest edge segments (56%) border on residential buildings. After the construction of buildings, 54% of the newly formed forest edges developed a high and steep structure. Unfavorable h/d dimension ratio was estimated for 16% of trees, more among the coniferous than among the deciduous trees. Similar characteristics of newly formed forest edges bordering on built-up areas were determined in other sub-urban forest patches, despite the smaller share of such forest edges (19% and 10%, respectively). Tools and methods presented in the research enable the implementation of concrete silvicultural practices in a realistic time period and extend to ensure that adequate forestry measures are taken to minimize possible disturbances.
Ključne besede: forest ecosystem services, forest edge stability, forest edge structure, LiDAR, urban forests
Objavljeno v DiRROS: 26.05.2020; Ogledov: 1894; Prenosov: 1031
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Povzetek: The Granata research site was established for the study of structure, growth and regeneration of silver fir-European beech single stem selection forest. Three phytocoenological relevés were carried out, all trees ?5 cm diameter at breast height (d.b.h.) were measured by full callipering, tree growth was analysed for sample trees, regeneration of tree species was registered on 63 sampling plots. In addition, historical data from past forest inventories werestudied. In the period from 1952 to 2003, the share of silver fir has decreased from 86% to 26%, the share of Norway spruce increased significantly,whereas the share of beech and sycamore has slightly increased. The current growing stock amounts to 350 m3 ha-1, with large-size diameter trees (d.b.h. ?50 cm) representing 51% of total growing stock. The site is divided into 16 stand patches with significant differences in tree species composition and diameter distribution. Regeneration is sufficient with silver fir prevailing in total number of seedlings (42%). 23% of all seedlings are damaged as a result of game browsing.
Ključne besede: selection forest, plenterwald, selection system management, stand structure, tree species composition, regeneration, diameter distribution
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4766; Prenosov: 2039
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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: 4371; Prenosov: 1744
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Povzetek: Social context as more or less neglected field of sustainable development is crucial for the implementation of forest management measures. We can consider it as a basis to cope with (changing) structure characteristics. Realisation of public services, which we face when coping with economic crisis, might take this into consideration. The Forest Service network serves as a scanner of needs in their social context. It is also a respondent to local specifics in the form of forest management measures. Evidence of research on the social research in Slovenian forestry is weak, although not non-existent. We tested asystem approach, a structuring method of general public. Segmentation, a method presented, is generally known in marketing and has not been used in Slovenian forestry up to now. The two-step clustering analysis of quantitative data gathered with an inquiry of study circles (form of community learning) was used and is described herewith. The results show three general value based segments of study circle participants. The role of Slovenian foresty is changing and is not independent of its dynamic and colourful social contexts, Recognition of the society structure and dynamics may contribute to the rationalisation of organisational models during the crisis period. Hoewer, grounded actualisation of recent organisational models is possible only by considering priorities of the society's segments. We conclude with suggestion for more R&D engagement in the social pillar of multifunctional forest management, in particular as the Slovenian social context is defined by dominance of private property and forest owners' ageing, which are far from being analysed and responded to.
Ključne besede: forestry, sustainable development, structure of society, segmentation, information flow, knowledge flow
Objavljeno v DiRROS: 12.07.2017; Ogledov: 4705; Prenosov: 1965
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