1. Proximity to riverbed influences physiological response of adult pedunculate oak treesLazar Kesić, Matjaž Čater, Saša Orlović, Bratislav Matović, Marko Stojanović, Mirjana Bojović, 2023, original scientific article Abstract: The pedunculate oak (Quercus robur L.) is economically and ecologically one of the most significant tree species in Serbia, however, little is known about the influence of the riverbed distance and its water supply on ecophysiological responses of this species. Given the limited information on the light-response curve of photosynthesis for oaks in southwest Srem, Serbia, the aim of this paper is to enhance understanding of their ecophysiological responses in this context. Maximum assimilation rate (Amax), the quantum yield (Ф), and light compensation point (LCP) were compared in adult trees situated along the transect from the river: (1) close to the river, (2) intermediate, (3) farthest from the river, and (4) forest reserve (second closest), with the first three transects being managed forests and the last one being an unmanaged forest reserve. The measurements were conducted in July during the first evidence of drought. The highest Amax rates were measured in all light intensities on the site closest to the river and the smallest on the site that was most distant to the water source. The most efficient were trees close to the river and the ones in the forest reserve. No significant difference between compensation points was confirmed for the studied groups of trees, although the forest reserve trees showed slightly higher values. The results demonstrated clear response between transects, which followed the distance from the riverbed. Pedunculate oak's reliance on groundwater is in tight relation with ecophysiological processes in trees; groundwater depletion may threaten its survival in areas distant from the river. Keywords: Quercus robur L., floodplain forest, drought, light-response curves, transects Published in DiRROS: 05.06.2024; Views: 1198; Downloads: 130
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2. 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: 303; Downloads: 154
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3. Tehnične smernice za ohranjanje in rabo genskih virov : dob in graden = Quercus robur/Quercus petraeaAlexis Ducousso, Sandor Bordacs, 2010, professional article Keywords: genski viri, drevesne vrste, tehnične smernice, dob, Quercus robur L., graden, Quercus petraea (Matt.) Liebl. Published in DiRROS: 12.12.2023; Views: 505; Downloads: 136
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4. Turkey oak (Quercus cerris L.) is more drought tolerant and better reflects climate variations compared to pedunculate oak (Quercus robur L.) in lowland mixed forests in northwestern Serbia : ǂa ǂstable carbon isotope ratio (δ13C) and radial growth approachSaša Kostić, Tom Levanič, Saša Orlović, Bratislav Matović, Dejan Stojanović, 2022, original scientific article Abstract: Tree-ring width (TRW), stable carbon isotope ratio (δ13C) and intrinsic water use efficiency (iWUE) data set chronologies were built for the period 1961–2000 for two oak species (pedunculate oak – Quercus robur L. and Turkey oak – Quercus cerris L.) in northwestern Serbia (Vojvodina province). We focused on the response of the two oak species to measured meteorological data (temperature, precipitation and cloud cover), drought events expressed by six meteorological drought indices, and river water level to better understand their drought tolerance and stress and to assess the reliability of the species response to climate and drought indices when using TRW or δ13C. Turkey oak exhibited better drought tolerance (and less drought stress) compared to pedunculate oak, as manifested, respectively, by less negative δ13C and lower iWUE values. Based on a generalised additive mixed model (GAMM) among the six drought indices studied, the standardised precipitation evapotranspiration index and the standardised precipitation index showed the best fit with both TRW and δ13C, while the Palmer drought severity index exerted a strong influence only on TRW. It was thus concluded that δ13C responds more strongly and rapidly to climate variations than TRW. Keywords: dendrochronology, stable carbon isotope, tree ring, Quercus robur, Quercus cerris, drought, climate change Published in DiRROS: 04.08.2022; Views: 829; Downloads: 655
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5. Poročilo o preskusu št.: LVG 2021-320 : opis vzorca: Quercus robur, listi : namen testiranja: sum na: GlivaNikica Ogris, Špela Jagodic, Zina Devetak, Tašja Cvelbar, Barbara Piškur, 2021, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, glive, hrast, Quercus robur Published in DiRROS: 26.10.2021; Views: 807; Downloads: 277
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6. Poročilo o preskusu št.: LVG 2021-166 : opis vzorca: Quercus robur, cela rastlina : namen testiranja: sum na: Erysiphe alphitoidesNikica Ogris, Andreja Kavčič, 2021, expertise, arbitration decision Keywords: varstvo gozdov, morfološke analize, Quercus robur, dob, hrastova pepelovka, Erysiphe alphitoides Published in DiRROS: 13.09.2021; Views: 1040; Downloads: 289
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7. 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, 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: 1071; Downloads: 758
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8. First report of European truffle ectomycorrhiza in the semi%arid climate of Saudi ArabiaSeema R. Bajaj, Sandesh J. Marathe, Tine Grebenc, Alessandra Zambonelli, Salem Shamekh, 2021, original scientific article Abstract: Tuber melanosporum Vittad. (Black or Périgord truffle) is a truffle native to the Mediterranean Southern Europe, popular for its unique flavor, and has great economic importance. The present work focused on assessing the possibility of cultivating T. melanosporum associated with Quercus robur L. in the desert climate of Saudi Arabia. The plantation was initiated in November 2018 by planting 271 oak seedlings in the Al-Qassim desert area and checked for survival and ectomycorrhiza development after 1.5 years of plantation maintenance. Amongst the 271 seedlings planted, 243 plants survived two harsh seasons (2019 and 2020), and the randomly selected and tested seedlings were still mycorrhized with T. melanosporum. The mycorrhization level with T. melanosporum was between 5 and 35% of all fine roots, and the share of contaminant ectomycorrhiza was low. In comparison to other areas where T. melanosporum is successfully cultivated, the Al-Qassim desert area has 10%15 °C higher average summer temperatures and a low total annual precipitation, which necessitates regular irrigation of the plantation. This work opens the avenue for an adapted, yet sustainable cultivation of T. melanosporum-inoculated oak tree in a desert climatic condition and introduces new opportunities of the agro-forest business in Saudi Arabia and GCC region. Keywords: Tuber melanosporum, Quercus robur, Desert climate, Truffle cultivation, Ectomycorrhiza Published in DiRROS: 26.01.2021; Views: 1275; Downloads: 399
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9. Isotopic and water relation responses to ozone and water stress in seedlings of three oak species with different adaptation strategiesClaudia Cocozza, Elena Paoletti, Tanja Mrak, Saša Zavadlav, Tom Levanič, Hojka Kraigher, Alessio Giovannelli, Yasutomo Hoshika, 2020, original scientific article Abstract: The impact of global changes on forest ecosystem processes is based on the species-specific responses of trees to the combined effect of multiple stressors and the capacity of each species to acclimate and cope with the environment modification. Combined environmental constraints can severely affect plant and ecological processes involved in plant functionality. This study provides novel insights into the impact of a simultaneous pairing of abiotic stresses (i.e., water and ozone (O3) stress) on the responses of oak species. Water stress (using 40 and 100% of soil water content at field capacity - WS and WW treatments, respectively) and O3 exposure (1.0, 1.2, and 1.4 times the ambient concentration - AA, 1.2AA, and 1.4AA, respectively) were carried out on Quercus robur L., Quercus ilex L., and Quercus pubescens Willd. seedlings, to study physiological traits (1. isotope signature [delta 13C, delta 18O and delta 15N], 2. water relation [leaf water potential, leaf water content], 3. leaf gas exchange [light-saturated net photosynthesis, Asat, and stomatal conductance, gs]) for adaptation strategies in a Free-Air Controlled Exposure (FACE) experiment. Ozone decreased Asat in Q. robur and Q. pubescens while water stress decreased it in all three oak species. Ozone did not affect delta 13C, whereas delta 18O was influenced by O3 especially in Q. robur. This may reflect a reduction of gs with the concomitant reduction in photosynthetic capacity. However, the effect of elevated O3 on leaf gas exchange as indicated by the combined analysis of stable isotopes was much lower than that of water stress. Water stress was detectable by delta 13C and by delta 18O in all three oak species, while delta 15N did not define plant response to stress conditions in any species. The delta 13C signal was correlated to leaf water content (LWC) in Q. robur and Q. ilex, showing isohydric and anisohydric strategy, respectively, at increasing stress intensity (low value of LWC). No interactive effect of water stress and O3 exposure on the isotopic responses was found, suggesting no cross-protection on seasonal carbon assimilation independently on the species adaptation strategy. Keywords: ozone, gas exchange, English oak, holm oak, downy oak, Quercus ilex L., Quercus robur L., Quercus pubescens Willd Published in DiRROS: 11.08.2020; Views: 1987; Downloads: 1197
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10. Analiza uspešnosti vzpostavitve nadomestnega habitata Črni log - Hotiška gmajna s poudarkom na rastni uspešnosti sadikSamar Al Sayegh-Petkovšek, 2019, original scientific article Abstract: Analizirali smo vzpostavitev nadomestnega habitata Črni log - Hotiška gmajna, ki je bil osnovan jeseni 2010 s sajenjem predvsem dveletnih sadik drevesnih in grmovnih vrst kot omilitveni ukrep zaradi izgube gozdnih površin v Črnem logu ob izgradnji avtocestnega odseka Beltinci-Lendava. V obdobju od 2011 do 2017 smo določili deleže preživetja, izdelali ocene vitalnosti in določili višinski ter debelinski prirastek za 566 sadik sedmih drevesnih vrst (črna jelša, dob, gorski javor, divja češnja, maklen, čremsa in poljski brest), rastočih na 26 raziskovalnih ploskvah. Sajenje je bilo praviloma uspešno pri vseh analiziranih vrstah, z izjemo divje češnje, kljub nekoliko večjem izpadu v drugem rastnem obdobju (dob, črna jelša, čremsa) oziroma še tri leta po sajenju (dob). Domnevamo, da je na zmanjšano preživetje sadik v letu 2012 vplivala suša v obdobju od oktobra 2011 do februarja 2012. Hkrati so v aprilu 2012 poročali o spomladanski pozebi, za katero je zlasti občutljiv dob, katerega povprečni delež preživetja se je povečal na okoli 70 % šele v letu 2015 in se nato ni več bistveno spremenil. Na podlagi opaženih poškodb divje češnje, čremse in maklena že v letu 2011 ter gorskega javorja in poljskega bresta v letu 2012 sklepamo, da je tudi objedanje divjadi vplivalo na manjši delež preživetja, vendar manj kot neugodne vremenske razmere. V tretjem letu (2013) po vzpostavitvi nadomestnega habitata sta bila povprečni višinski in povprečni debelinski prirastek na koreninskem vratu za vse drevesne vrste, z izjemo divje češnje, pozitivna in bistveno večja od prejšnjega rastnega obdobja (april 2011 - april 2012). Upoštevaje deleže preživetja, višinsko in debelinsko priraščanje ter delež vitalnih sadik je najuspešnejša drevesna vrsta črna jelša, kar je pogoj za oblikovanje načrtovanega jelševega sestoja. Med vsemi opazovanimi vrstami pa je najmanj uspešna divja češnja. Delež preživetja sadik je bil namreč vseskozi manjši od zahtevanih 70 %, zato smo ocenili, da sajenje divje češnje na izbranih raziskovalnih ploskvah ni bilo uspešno. Na podlagi ugotovitev so jo že v jeseni 2013 ponovno sadili, vendar zunaj raziskovalnih ploskev in zato slednje ne vpliva na predstavljene rezultate. Lahko zaključimo, da se med Hotiško gmajno in Črnim logom uspešno vzpostavlja gozdni habitat, ki nadomešča prejšnje njivske površine in da bo lahko nadomestil oziroma omilil škodo zaradi izgube gozdnih površin v Črnem logu ob izgradnji avtoceste A5 na odseku Beltinci-Lendava. Pričakujemo, da bo nastali gozdni sestoj v naslednjih letih omogočil gnezdenje srednjega detla in belovratnega muharja, ki sta zaradi gradnje avtoceste izgubila del svojega habitata. Keywords: nadomestni habitat, Črni log - Hotiška gmajna, Alnus glutinosa (L.) Gartn., Quercus robur L., Acer pseudoplatanus L., Acer campestre L., Prunus avium L., Prunus padus L., Ulmus minor Mill., sadike Published in DiRROS: 08.08.2019; Views: 3315; Downloads: 931
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