1. Three decades of understorey vegetation change in Quercus-dominated forests as a result of increasing canopy mortality and global change symptomsJanez Kermavnar, Lado Kutnar, 2024, izvirni znanstveni članek Povzetek: Questions The long-term response of understorey vegetation to increasing tree mortality has rarely been addressed in resurvey studies. For two Quercus-dominated forest types, we asked: (a) How did overstorey alterations, induced by canopy mortality, affect understorey diversity and composition? (b) Is there a signal of global change effects on understorey communities? (c) Are these assemblages experiencing a homogenization process? Location Five sites in Quercus robur (QR) and four sites in Q. petraea (QP) forests, Slovenia. Methods We studied changes in vascular plants in the understorey layer from 1992/1993 to 2023 across 45 permanent 20 m × 20 m plots in QR and QP forests, respectively. Vegetation surveys were carried out following the standard Braun-Blanquet method. We compared original surveys with recent resurveys using multivariate analysis, ecological indicator values (EIV), plant traits and methods that quantify changes in individual species. Results Since the early 1990s, tree layer cover decreased from 95% to an average of 55% in QR, whereas it remained relatively high (77%) in QP plots. This resulted in denser understorey vegetation and a significant increase in plot-level species richness in QR forests, but a slight decrease in QP forests. The extensive loss of canopy cover and disturbance effects in QR forests caused significant changes in species composition. Species turnover in QR was driven by colonization of new disturbance-tolerant taxa characterized by ruderal traits, whereas the compositional shift in QP was to a greater extent due to species losses. We detected a process of vegetation thermophilization (increase in EIV-temperature), suggesting an effect of rapid climatic warming. Understorey communities are now more similar to each other than 30 years ago, indicating a decrease in beta-diversity (floristic homogenization). Conclusions Despite some common trends, vegetation responses were forest type-specific. Our study presents evidence of understorey vegetation changes triggered by increased canopy mortality (a strong local driver particularly in QR plots) and also points to the signal of global change symptoms (thermophilization, homogenization), which acted rather independently from the observed decline in tree layer cover.
Ključne besede: floristic homogenization, forest disturbances, permanent vegetation plots, Quercus robur, Quercus petraea, resurvey study, Slovenia, thermophilization, tree layer cover
Objavljeno v DiRROS: 11.11.2024; Ogledov: 679; Prenosov: 572
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2. Poročilo o preskusu št.: LVG 2024-022 : vzorec št. 2024/00043/THTine Hauptman, Špela Hočevar, Barbara Piškur, 2024, izvedensko mnenje, arbitražna odločba Ključne besede: varstvo gozdov, morfološke analize, Quercus petraea, Fusarium sp., Tolypocladium sp., molekularne analize, javna gozdarska služba
Objavljeno v DiRROS: 23.05.2024; Ogledov: 769; Prenosov: 418
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3. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: long-term vegetation change, invasive non-native plants, oak mortality, Quercus robur, Quercus petraea, canopy openness, Impatiens parviflora, Slovenia
Objavljeno v DiRROS: 19.04.2024; Ogledov: 989; Prenosov: 814
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4. Poročilo o preskusu št.: LVG 2024-010 : vzorec št. 2024/00044Nikica Ogris, Maarten De Groot, 2024, izvedensko mnenje, arbitražna odločba Ključne besede: varstvo gozdov, morfološke analize, graden, Quercus petraea, sušenje, hiranje, kompleksna bolezen
Objavljeno v DiRROS: 13.02.2024; Ogledov: 1115; Prenosov: 325
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5. Tehnične smernice za ohranjanje in rabo genskih virov : dob in graden = Quercus robur/Quercus petraeaAlexis Ducousso, Sandor Bordacs, 2010, strokovni članek Ključne besede: genski viri, drevesne vrste, tehnične smernice, dob, Quercus robur L., graden, Quercus petraea (Matt.) Liebl.
Objavljeno v DiRROS: 12.12.2023; Ogledov: 1267; Prenosov: 396
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6. Pomen analize dominantnih dreves za gozdnogospodarsko načrtovanje na primeru kisloljubnega bukovja z rebrenjačoAndrej Bončina, 2022, izvirni znanstveni članek Povzetek: 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.
Ključne besede: višinska rast, debelinska rast, rastiščni indeks, rastiščni produkcijski indeks, Fagus sylvatica, Picea abies, Quercus petraea, Pinus sylvestris, Castanea sativa
Objavljeno v DiRROS: 11.08.2022; Ogledov: 1991; Prenosov: 622
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7. Poročilo o preskusu št.: LVG 2021-177 : opis vzorca: Quercus petraea, les, lubje, sekanci, št. enot 5 : namen testiranja: sum na: Xylosandrus crassiusculusAndreja Kavčič, 2021, izvedensko mnenje, arbitražna odločba Ključne besede: varstvo gozdov, morfološke analize, Quercus petraea, Xylosandrus crassiusculus
Objavljeno v DiRROS: 24.09.2021; Ogledov: 1339; Prenosov: 0 |
8. Contrasting resource dynamics in mast years for European Beech and Oak - a continental scale analysisAnita Nussbaumer, Arthur Gessler, Sue Benham, B. De Cinti, Sophia Etzold, Morten Ingerslev, Frank Jacob, François Lebourgeois, Tom Levanič, Hrvoje Marjanović, 2021, izvirni znanstveni članek Povzetek: 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.
Ključne besede: climate change, Fagus sylvatica, long-term monitoring, mast fruiting, Quercus petraea, Quercus robur, resource dynamics
Objavljeno v DiRROS: 15.07.2021; Ogledov: 1817; Prenosov: 1287
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9. Revno rastišče in navadno ohmelje (Loranthus europaeus) je prizadelo graden na Dularjevem bregu pri Zidanem mostuNikica Ogris, Tine Hauptman, Tom Levanič, Dušan Jurc, Barbara Slabanja, Boštjan Pihler, 2010, strokovni članek Ključne besede: suša, stres, navadno ohmelje, Loranthus europaeus, Quercus petraea, bolezni drevja, gozdovi, varstvo gozdov
Objavljeno v DiRROS: 29.07.2020; Ogledov: 2578; Prenosov: 1472
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10. Effect of spatial scale and harvest on heterogeneity of forest floor CO2 efflux in a sessile oak forestEva Dařenová, Matjaž Čater, 2020, izvirni znanstveni članek Povzetek: 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.
Ključne besede: gap fraction, LAI, Quercus petraea, soil respiration, soil water content
Objavljeno v DiRROS: 20.02.2020; Ogledov: 2800; Prenosov: 207 |
