Pseudodidymella fagi in Slovenia : first report and expansion of host rangeNikica Ogris
, Ana Brglez
, Barbara Piškur
Povzetek: 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.
Ključne besede: Pycnopleiospora fagi, leaf blotch, pathogenicity test, inoculation test, Fagus orientalis, Fagus sylvatica, Quercus petraea, mycopappus-like propagule, Carpinus betulus, host switching
DiRROS - Objavljeno: 23.08.2019; Ogledov: 1678; Prenosov: 967
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A study of important entomofauna in oak forests of SloveniaMiroslav Harapinov
, Maja Jurc
Povzetek: Insects in 9 research areas in pedunculate oak and sessile oak forests in Slovenia have been studied. We identified 35 insect species as well as two genera from 13 families. The defoliation of oak leaves in studied forests was between 10 and 90 %. More than 80 % of the defoliation was caused by mottled umber and winter moth (Erannis defoliaria Cl., Operophthera brumata L.). Leaf-roll moths are an important group of pests of oak leaves and acorns. The most numerous is the green leaf-roll moth, Tortrix viridana L., followed by Archips crataegana Hb., Laspeyresia splendana Hb. and Laspeyresia amplana Hb. The ratio of appearance of oak sawflies (Apethymus abdominalis Lep. and Apethymus braccatus Gmel.) was 9 : 1. During the past 10 years, oak miner (Tischeria complanella Hb.) has attacked young oak trees heavily. Acorn destroyers (Balaninus glandium Mrsh. and Balaninus nucum L.) were important acorn pests. During the gradation of defoliators in the Prekmurje region of Slovenia there was an increased population density of their predators, such asground beetles and burying beetles (Calosoma sycophanta L., Calosoma inquisitor L., Carabus spp., Xylodrepa quadripunctata L. We can confirm that the health of oak forests in Slovenia is better than in Croatia and southeastern Europe.
Ključne besede: dob, Quercus robur, graden, Quercus petraea, gozdarska entomologija, Insecta, žuželka, škodljivec, entomofauna, Slovenija, pedunculate oak, Quercus robur, sessile oak, Quercus petraea, forest entomology, Insecta, entomofauna, Slovenija
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2228; Prenosov: 605
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Vloga fitinske kisline pri shranjevanju želoda gradna (Quercus petraea (Matt.) Liebl.)Sašo Žitnik
, Hojka Kraigher
Povzetek: Cilj raziskave je razviti nove postopke daljšega shranjevanja gradnovega želoda, ki bi bili poceni in praktični, saj je z zdaj znanimi metodami zaradi rekalcitrantnosti želoda možno shranjevati le nekaj mesecev. Raziskovanje sloni na hipotezi, da je vitalnost želoda po daljšem shranjevanju v pozitivni korelaciji z vsebnostjo fitinske kisline v njem, kar je v pozitivni korelaciji z vsebnostjo razpoložljivega fosforja v tleh. Poskus je zastavljen kot študija enega primera na dveh izbranih ploskvah, poraslih z gradnom. Ploskvi se bistveno razlikujeta po vsebnosti celotnega fosforja v listih, kar smo uporabili kot kazalec razpoložljivega fosforja v tleh. Želod smo nabrali na ploskvah oktobra 1997. Nato je bil shranjen 9 mesecev, do avgusta 1998. Pred shranjevanjem in nato vsake tri mesece smo opravili naslednje analize: vlažnost in kalivost želoda, vsebnost hranil (P, K, Ca, Mg) in vsebnost fitinske kisline. Pokazalo se je, da je na ploskvi z večjo vsebnostjo celotnega fosforja v listih tudi večja vsebnost celotnega fosforja v želodu. Na tej ploskvi je tudi večja vsebnost fitinske kisline v želodu, hkrati pa je večja njegova kalivost. Vendar so razlike opazne samo na začetku shranjevanja,nato postopoma izginejo. Rezultati kažejo, da bi lahko obstajala pozitivna korelacija med vitalnostjo želoda po daljšem času shranjevanja, vsebnostjo fitinske kisline v njem in vsebnostjo fosforja v tleh, vendar dosedanji rezultati niso pokazali statistično značilnih razlik.
Ključne besede: semenarstvo, želod, graden, Quercus petraea (Matt.(Liebl.)), shranjevanje, fitinska kislina, fosfor, kalivost, Slovenija
DiRROS - Objavljeno: 12.07.2017; Ogledov: 2149; Prenosov: 622
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Effect of spatial scale and harvest on heterogeneity of forest floor CO2 efflux in a sessile oak forestEva Dařenová
, Matjaž Čater
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
DiRROS - Objavljeno: 20.02.2020; Ogledov: 1111; Prenosov: 207
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
Ključne besede: suša, stres, navadno ohmelje, Loranthus europaeus, Quercus petraea, bolezni drevja, gozdovi, varstvo gozdov
DiRROS - Objavljeno: 29.07.2020; Ogledov: 872; Prenosov: 596
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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
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
DiRROS - Objavljeno: 15.07.2021; Ogledov: 260; Prenosov: 167
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