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Query: "keywords" (Quercus petraea) .

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Habitat degradation facilitates the invasion of Neophytes : a resurvey study based on permanent vegetation plots in oak forests in Slovenia (Europe)
Janez Kermavnar, Lado Kutnar, 2024, original scientific article

Abstract: The spread of neophytes (non-native plant species) challenges the conservation status and ecological integrity of forests, especially in lowland areas. Long-term resurvey studies are needed to evaluate the temporal dynamics of neophytes in forests; however, such data are scarce. In 2023, we resampled a set of 45 permanent vegetation plots (established in 1992/93) in two forest vegetation types: oak–hornbeam forests dominated by Quercus robur and colline oak–beech forests dominated by Q. petraea. Over the last 30 years, oak forests have experienced extensive oak tree mortality, with the degree of habitat degradation being greater in Q. robur forests. In the early 1990s, only three neophytes with low abundance were recorded across all plots. In the 2023 resurvey, the total number of neophytes increased to 22 species (15 herbaceous and 7 woody species), comprising 6.9% of the total species pool in the understory layer. The increase in the plot-level number and cover of neophytes was significant in plots dominated by Q. robur but not in those with Q. petraea. The most frequent neophytes were Impatiens parviflora (present in 31% of plots), Solidago gigantea (27%), Erigeron annuus (16%) and Erechtites hieraciifolia (16%). The richness and cover of neophytes were significantly affected by the tree layer cover (negative correlation) and the degree of soil disturbance (positive correlation). All neophytes established in disturbed patches, whereas the occurrence of I. parviflora was exceptional as it was able to colonize less degraded, shaded understory environments. Habitat degradation (the mortality-induced loss of stand-forming oak trees resulting in extensive tree layer cover decrease) emerged as a key driver promoting neophyte proliferation, coupled with the impact of management-induced disturbances affecting overstory and soil conditions. The spread is expected to continue or even intensify in the future because novel light regimes and disturbances make forest habitats less resistant to neophyte proliferation.
Keywords: long-term vegetation change, invasive non-native plants, oak mortality, Quercus robur, Quercus petraea, canopy openness, Impatiens parviflora, Slovenia
Published in DiRROS: 19.04.2024; Views: 244; Downloads: 103
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Poročilo o preskusu št.: LVG 2024-010 : vzorec št. 2024/00044
Nikica Ogris, Maarten De Groot, 2024, expertise, arbitration decision

Keywords: varstvo gozdov, morfološke analize, graden, Quercus petraea, sušenje, hiranje, kompleksna bolezen
Published in DiRROS: 13.02.2024; Views: 298; Downloads: 79
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Pomen analize dominantnih dreves za gozdnogospodarsko načrtovanje na primeru kisloljubnega bukovja z rebrenjačo
Andrej Bončina, 2022, original scientific article

Abstract: Poznavanje razvoja dominantnega drevja je pomembno za spremljavo razvoja enomernih sestojev, določanje režima redčenj, ciljnih premerov drevesnih vrst in optimalnega razmerja razvojnih faz ter ocenjevanje produkcijske sposobnosti gozdnih rastišč. S podatki stalnih vzorčnih ploskev smo analizirali debelinsko in višinsko rast dominantnih dreves petih drevesnih vrst kisloljubnega bukovja z rebrenjačo (smreka, bukev, graden, rdeči bor in kostanj). Za vrste smo ocenili rastiščni produkcijski indeks (SPI), ki je dominanta višina drevja pri prsnem premeru 45 cm, rastiščni indeks (SI) in prikazali postopek določanja optimalnega razmerja razvojnih faz glede na drevesno sestavo sestojev ter odločitev o ciljnih premerih drevja in pomlajevanju sestojev. Vrednosti SPI za bukev, smreko, graden, rdeči bor in kostanj so 28,4; 31,1; 25,1; 26,1 in 23,2, vrednosti SI pa 27,9; 32,5; 20,9; 22,9 in 21,7. Optimalni deleži razvojnih faz so odvisni od izbrane drevesne sestave gozdov ter odločitev glede ciljnih premerov in pomlajevanja sestojev. Model debelinskega priraščanja bukve kaže, da na njeno debelinsko rast pozitivno vplivajo prsni premer, produktivnost rastišča in raznomernost sestojev, negativno pa delež bukve v sestoju, sestojna temeljnica in naklon terena.
Keywords: višinska rast, debelinska rast, rastiščni indeks, rastiščni produkcijski indeks, Fagus sylvatica, Picea abies, Quercus petraea, Pinus sylvestris, Castanea sativa
Published in DiRROS: 11.08.2022; Views: 1015; Downloads: 283
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Contrasting resource dynamics in mast years for European Beech and Oak - a continental scale analysis
Anita Nussbaumer, Arthur Gessler, Sue Benham, B. De Cinti, Sophia Etzold, Morten Ingerslev, Frank Jacob, François Lebourgeois, Tom Levanič, Hrvoje Marjanović, 2021, original scientific article

Abstract: Resource allocation to different plant tissues is likely to be affected by high investment into fruit production during mast years. However, there is a large knowledge gap concerning species-specific differences in resource dynamics. We investigated the influence of mast years on stem growth, leaf production, and leaf carbon (C), nitrogen (N), and phosphorus (P) concentrations and contents in Fagus sylvatica, Quercus petraea, and Q. robur at continental and climate region scales using long-term data from the International Co-operative Programme on Assessment and Monitoring of Air Pollution Effects on Forests (ICP Forests) and similar datasets. We discussed the results in the light of opposing resource dynamics hypotheses: (i) resource accumulation before mast years and exhaustion after mast years (resource storage hypothesis), (ii) shifting resources from vegetative to generative compartments (resource switching hypothesis), and (iii) investing resources concurrently in both vegetative and generative compartments (resource matching hypothesis). Linear mixed-effects modelling (LMM) showed that both stem growth and leaf production were negatively influenced by weather conditions which simultaneously lead to high fruit production. Thus, the impact of generative on vegetative growth is intermixed with effects of environmental factors. Superposed epoch analyses and LMM showed that for mast behaviour in F. sylvatica, there are indicators supporting the resource storage and the resource switching hypotheses. Before mast years, resources were accumulated, while during mast years resources switched from vegetative to generative tissues with reduced stem and leaf growth. For the Quercus species, stem growth was reduced after mast years, which supports the resource storage hypothesis. LMM showed that leaf C concentrations did not change with increasing fruit production in neither species. Leaf N and P concentrations increased in F. sylvatica, but not in Quercus species. Leaf N and P contents decreased with increasing fruit production in all species, as did leaf C content in F. sylvatica. Overall, our findings suggest different resource dynamics strategies in F. sylvatica and Quercus species, which might lead to differences in their adaptive capacity to a changing climate.
Keywords: climate change, Fagus sylvatica, long-term monitoring, mast fruiting, Quercus petraea, Quercus robur, resource dynamics
Published in DiRROS: 15.07.2021; Views: 1025; Downloads: 715
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Effect of spatial scale and harvest on heterogeneity of forest floor CO2 efflux in a sessile oak forest
Eva Dařenová, Matjaž Čater, 2020, original scientific article

Abstract: Soil respiration is the second largest flux of carbon between terrestrial ecosystems and the atmosphere and it is substantially sensitive to climate change. Monitoring CO2 efflux and its upscaling from field measurements to the ecosystem level is a complex task, due to the high spatial and temporal variability of the fluxes. Human intervention, e.g. through forest harvest, may change both CO2 efflux and its spatial heterogeneity. The objective of our study was to quantify spatial heterogeneity of soil CO2 efflux within and among plots distributed within a topographically variable sessile oak forest stand before and after harvesting. Forest floor CO2 efflux, soil temperature and soil water content were measured monthly in a sessile oak forest during two growing seasons: one before and one after harvesting. Stand structure characteristics (gap fraction, leaf area index, tree number and size) and the amount of understory also were determined. Relationships between individual variables and spatial heterogeneity were analyzed. The small-scale spatial heterogeneity (expresses as the coefficient of variation) of forest floor CO2 efflux and soil water content (SWC) in the undisturbed forest was low, at maximum 0.22 and 0.13, respectively. Studied variables had no effect on spatial heterogeneity of forest floor CO2 efflux except for the amount of understorey vegetation which positively correlated with forest floor CO2 efflux. Although the studied forest was situated in topographically variable terrain, we observed that inter-plot heterogeneity of forest floor CO2 efflux was lower than that within plots. Stand harvest increased the intra-plot heterogeneity of forest floor CO2 efflux but did not affect the inter-plot heterogeneity. This leads to the conclusion that the number of positions within an individual plot should increase after harvest but the number of plots may remain unchanged to determine adequately ecosystem forest floor CO2 efflux.
Keywords: gap fraction, LAI, Quercus petraea, soil respiration, soil water content
Published in DiRROS: 20.02.2020; Views: 2012; Downloads: 207

10.
Pseudodidymella fagi in Slovenia : first report and expansion of host range
Nikica Ogris, Ana Brglez, Barbara Piškur, 2019, original scientific article

Abstract: The fungus Pseudodidymella fagi is spreading in Europe and causing leaf blotch of European beech, Fagus sylvatica. Between 2008 and 2017, outbreaks of P. fagi were observed on European beech in Switzerland, Germany (also on F. orientalis), Austria, and Slovakia. In Slovenia, leaf blotch symptoms were first observed on F. sylvatica in 2018. P. fagi was identified as the causal agent of the observed symptoms in Slovenia by morphological examinations together with sequencing of the internal transcribed spacer (ITS) region of the rDNA. This study links the fungus to the expansion of the known distribution of the disease to Slovenia, and based on in vitro pathogenicity trials, also to a new potential host, Quercus petraea. The pathogenicity tests confirmed F. sylvatica and F. orientalis as hosts for P. fagi, but not Castanea sativa, where pathogenicity to F. orientalis was proved for first time in vitro. Although Koch%s postulates could not be proven for C. sativa, it seems to be partially susceptible in vitro because some of the inoculation points developed lesions. Additionally, damage to Carpinus betulus related to P. fagi near heavily infected beech trees was observed in vivo but was not tested in laboratory trials. Based on the results and our observations in the field, it is likely that P. fagi has a wider host range than previously thought and that we might be witnessing host switching.
Keywords: Pycnopleiospora fagi, leaf blotch, pathogenicity test, inoculation test, Fagus orientalis, Fagus sylvatica, Quercus petraea, mycopappus-like propagule, Carpinus betulus, host switching
Published in DiRROS: 23.08.2019; Views: 2605; Downloads: 1637
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