Primoz Simoncic

<p>In the December 2017, 211 000 ha of Slovenian forests or 2 201 000 m<sup>3</sup> were severely damaged by the windstorm. The damage was greatest in the adult beech-silver fir forest stands. In each management district (FMD) with different share of damaged forested area - Kočevje (69%), Postojna (22%) and Ljubljana (19%), research location were established to evaluate soil properties, root characteristics and ecophysiological regeneration response of predominating tree species in damaged stands as well as the economic effect of the windstorm on sensitive high karst sites. The restoration and regeneration efficiency of latest disaster (2017) was also compared with restoration efficiency of areas damaged in 2008, identifying possible specifics / differences and providing guidelines for their optimal recovery.</p><p>Timber database from Slovenian Forest Service with data about felling and felling reasons between Dec. 2017 and the end of 2019 was used to evaluate economic losses. The total amount from the database was multiplied by the shares of individual quality category, obtaining the quantitative assortment structure according to the actual felling. We used tables of assortment losses caused by wind to estimate the actual assortment loss and multiplied those with 2018 roundwood market prices. Estimated cumulative biomass loss amounted 205 855 m<sup>3</sup> - 5.6% less, compared to regular felling, or 16.1 million €.</p><p>Physical soil properties between plots damaged by wind and control areas without damage did not confirm any significant difference in relation to weather and microsite conditions (rootstock, exposition, altitude, species structure of stands, microrelief). Characteristics of root systems of the most affected tree species - fir, spruce and beech did not differ between damaged and neighboring undamaged sites. An overview of fir and spruce windbreaks during the 1995 - 2018 period outlined the cumulative effect of multiple site conditions with strong wind, severely reducing the mechanical stability of fir and spruce; consequently, the following weather events with even mild wind intensities resulted in calamity.</p><p>Natural regeneration ability on all plots of recent windthrow shows successful regeneration of beech, maple, and fir in all light categories of damaged stands, but questionable regeneration of fir, which is in tight relation with ungulate browsing.  For comparison with regeneration after windthrow in 2017, we analyzed successional development in three windthrow areas from 2008. Seedling densities ranged from 5000 to 9000 ha-1, with the highest densities in the 150-300 cm height class. Within plots with natural regeneration, height and species diversity were better compared to planted plots. Shade-tolerant species increased in plots at lower elevations, while pioneer species still increased at higher elevations. Overall browsing was moderate, but silver fir and sycamore had difficulty establishing. The results indicate that regeneration spreads from areas that were covered with seedlings shortly after windthrow and that certain parts will not be covered with regeneration for a longer period.</p>

UDK 630*114:630*242(497.6) Large areas of European fir-beech forests are characteristic for the Dinaric Mountains and represent one of the most important forest ecosystems in the region. Such forests extend in high karst plateaus from the eastern Alps in SE Slovenia to the N Albanian massifs at the altitudes from 700 to 1200 (1500) m a.s.l. This is the area with a diverse landscape configuration. The bedrock is consisted of limestone, occasionally of dolomite limestone and dolomite. There are various soil conditions, where in a small area, a mosaic of Leptosols, Rendzic Leptosols, Chromic Cambisol, Calcaric and Chromic Luvisols occur. As climate conditions are very favourable for the growth of forests (high precipitation and air humidity), production function of wood is much more emphasized. Very little is known about the long-term effects of forest management and intensity of logging on soil organic matter quality and carbon stocks in these forest soils. Therefore, with an objectiv...

Skladno z Zakonom o gozdovih del Javne gozdarske službe (JGS) opravlja tudi Gozdarski institut Slovenije (GIS). Aktivnosti JGS na GIS so usmerjene predvsem v strokovno podporo Ministrstvu za kmetijstvo, gozdarstvo in prehrano ter Zavodu za gozdove Slovenije. Podrocja dela JGS / GIS so naslednja: spremljanje stanja razvrednotenja in poskodovanosti gozdov, usmerjanje in strokovno vodstvo porocevalske, prognosticno-diagnosticne službe za gozdove, strokovno usmerjanje gozdne semenarske in drevesnicarske dejavnosti, razvoj informacijskega sistema za gozdove, priprava strokovnih podlag za opravljanje del v gozdovih. GIS v okviru JGS opravlja tudi javna pooblastila. V 25 letih obstoja JGS/GIS so se nabrali stevilni dosežki ter za slovensko gozdarstvo pomembni rezultati. V prispevku predstavljamo poudarke JGS/GIS, za katere menimo, da so aktualni in zanimivi za strokovno javnost.

PurposeSoil carbon dynamics were studied at four different forest stands developed on bedrocks with contrasting geology in Slovenia: one plot on magmatic granodiorite bedrock (IG), two plots on carbonate bedrock in the karstic-dinaric area (CC and CD), and one situated on Pleistocene coalluvial terraces (FGS).Materials and methodsThroughfall (TF) and soil water were collected monthly at each location from June to November during 2005–2007. In soil water, the following parameters were determined: T, pH, total alkalinity, concentrations of Ca2+ and Mg2+, dissolved organic carbon (DOC), and Cl− as well as δ13CDIC. On the other hand, in TF, only the Cl− content was measured. Soil and plant samples were also collected at forest stands, and stable isotope measurements were performed in soil and plant organic carbon and total nitrogen and in carbonate rocks. The obtained data were used to calculate the dissolved inorganic carbon (DIC) and DOC fluxes. Statistic analyses were carried out to compare sites of different lithologies, at different spatial and temporal scales.Results and discussionDecomposition of soil organic matter (SOM) controlled by the climate can explain the 13C and 15 N enrichment in SOM at CC, CD, and FGS, while the soil microbial biomass makes an important contribution to the SOM at IG. The loss of DOC at a soil depth of 5 cm was estimated at 1 mol m−2 year−1 and shows no significant differences among the study sites. The DOC fluxes were mainly controlled by physical factors, most notably sorption dynamics, and microbial–DOC relationships. The pH and pCO2 of the soil solution controlled the DIC fluxes according to carbonate equilibrium reactions. An increased exchange between DIC and atmospheric air was observed for samples from non-carbonate subsoils (IG and FGS). In addition, higher δ13CDIC values up to −19.4 ‰ in the shallow soil water were recorded during the summer as a consequence of isotopic fractionation induced by molecular diffusion of soil CO2. The δ13CDIC values also suggest that half of the DIC derives from soil CO2 indicating that 2 to 5 mol m−2 year−1 of carbon is lost in the form of dissolved inorganic carbon at CC and CD after carbonate dissolution.ConclusionsMajor difference in soil carbon dynamics between the four forest ecosystems is a result of the combined influence of bedrock geology, soil texture, and the sources of SOM. Water flux was a critical parameter in quantifying carbon depletion rates in dissolved organic and inorganic carbon forms.

SummaryThe transition of grasslands to forests influences many ecosystem processes, including water and temperature regimes and the cycling of nutrients. Different components of the carbon biogeochemical cycle respond strongly to woody plant encroachment; as a consequence, the carbon balance of the invaded grasslands can change markedly. In our research, we studied the response of soil respiration (RS) to natural succession of calcareous grassland. We established two research sites, called grassland and invaded site, at each of which eddy flux measurement were also performed. Within these sites, triplicate plots were fenced for soil flux measurements. At the invaded site, measurements were performed for forest patches and grassy spaces separately. Soil respiration was strongly dependent on temperature and reached 8–12 µmol CO2 m−2 s−1 in mid‐summer; it was greater at the grassland than at the invaded site. RS dependence on temperature and soil water content was similar between the d...

The parent material is considered the most important of Slovenia’s soil formation factors. Chemically, only partially changed parent material heavily influences soil properties. 93% of the Slovenian territory is composed of sedimentary rocks, mainly limestone and dolomite, and only 4% belongs to the metamorphic group, while 3% is of magmatic origin. After the parent material, topography is certainly deemed to be Slovenia’s next most important and prominent natural soil formation factor. Very young structural relief predominates, which has a direct impact on the soil water and micro- and mezzo-climatic conditions. The influence of climate on Slovenian soils is more general; it is mostly considered to be a constant and does not have an important interregional distinguishing aspect. Due to its importance, water as a soil formation factor deserves a special place in the Slovenian Soil Classification, since on the first level of classification soil is divided on the basis of hydromorphis...

Spatially explicit knowledge of recent and past soil organic carbon (SOC) stocks in forests will improve our understanding of the effect of human- and non-human-induced changes on forest C fluxes. For SOC accounting, a minimum detectable difference must be defined in order to adequately determine temporal changes and spatial differences in SOC. This requires sufficiently detailed data to predict SOC stocks at appropriate scales within the required accuracy so that only significant changes are accounted for. When designing sampling campaigns, taking into account factors influencing SOC spatial and temporal distribution (such as soil type, topography, climate and vegetation) are needed to optimise sampling depths and numbers of samples, thereby ensuring that samples accurately reflect the distribution of SOC at a site. Furthermore, the appropriate scales related to the research question need to be defined: profile, plot, forests, catchment, national or wider. Scaling up SOC stocks fro...