1. Tubakia spp., Didymella macrostoma and Apiognomonia errabunda causing leaf spot and anthracnose of Quercus robur in the Mura-Drava-Danube Biosphere ReserveMilica Zlatković, Marcus Sallmannshofer, Silvio Schueler, Thomas L. Cech, Milutin Djilas, Gernot Hoch, Katharina Lapin, Nikica Ogris, Barbara Piškur, Katharina Schwanda, Srđan Stojnić, Marjana Westergren, Saša Orlović, 2024, izvirni znanstveni članek Povzetek: The Mura-Drava-Danube transboundary UNESCO Biosphere Reserve represents one of the best-preserved wetlands in Europe. The Reserve’s riparian forests play a significant role in ecosystem functioning and pedunculate oak (Quercus robur) is one of the keystone species of these forests. In recent years, pedunculate oak trees in the Reserve displayed symptoms of necrotic lesions on their leaves. The lesions varied in size, from small, circular to irregular reddish brown to grayish spots to larger necrotic areas that resembled leaf anthracnose and extended along the leaf nerves. In 2021, symptomatic leaves were collected in three countries of the Reserve, i.e. Austria, Slovenia, and Serbia to identify the causative agents of these diseases. Fungal cultures were obtained from symptoms and identified using morphology and multilocus phylogenetic analyses of the ITS rDNA, partial LSU rDNA, tef 1-α, BT2, CAL, ACT, and RPB2 genes. The fungi were identified as Tubakia dryina, Tubakia sp. (Tubakia dryinoides sensu lato), Didymella macrostoma, and Apiognomonia errabunda. Pathogenicity tests done by inoculating the leaves of one-year old pedunculate oak plants revealed that the isolated fungi caused symptoms as those seen in the forest. To our knowledge, this study represents the first report of D. macrostoma as the cause of pedunculate oak leaf spot disease in Serbia and worldwide. It is also the first finding of Tubakia leaf spot disease of pedunculate oak caused by T. dryina in Austria and Serbia. Moreover, Tubakia sp. was proven to be another causative agent of Tubakia leaf spot disease. Additionally, oak anthracnose caused by A. errabunda was found for the first time on pedunculate oak leaves in Austria and Slovenia. During the past decade, pedunculate oak trees have been facing increasing threats from multiple abiotic and biotic factors which has resulted in decline and absence of natural regeneration of these trees. The results of this study add to the understanding of the contributing factors to the decline of pedunculate oak in riparian forests and are important for the development of management strategies to counteract this decline.
Ključne besede: Mura-Drava-Danube Biosphere Reserve, riparian forests, Tubakia leaf spot, Didymella macrostoma, oak anthracnose, pedunculate oak, leaf spot diseases
Objavljeno v DiRROS: 23.04.2024; Ogledov: 1; Prenosov: 0
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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, 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: 34; Prenosov: 20
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3. Researching the change in the weight of split oak firewood due to different drying methodsAmina Gačo, 2021, objavljeni znanstveni prispevek na konferenci Povzetek: In this paper, the influences of stacking methods and drying places of split oak firewood in winter conditions (Quercus cerris) have been experimentally and theoretically investigated, due to the great importance of use in heating with such wood. The research was conducted on a sample of 48 pieces of logs with bark made of freshly cut oak. The logs were obtained by mechanized technology with the help of grafting by a hydraulic splitter and a chainsaw. Each log was measured for a research length of 0.30 m, marked with numbers 1-24. On each log, the weight was measured on a scale of 5 kg with an accuracy of 0.5 grams. Drying of logs was performed in two places. The first drying place was in outdoor conditions, sheltered from the snow and ventilated. The second place was indoors, at approximately constant room temperature. The logs were stacked in a crossed way for better air circulation. They were dried between 15/12/2020 and 15/02/2021, a total of 62 days. The average initial weight of logs dried in the facility was 1130.3 g, in the dried state the average weight was 952.87 g, which represented 84.3% of the original weight. The average initial weight of logs dried in outdoor conditions was 1192.125 g, in the dried state 1076.37 g, which represented 90.29% of the original weight. The average initial water content in the logs dried in the facility was 37.9%, in the dried state it was 27.5%. For logs dried in outdoor conditions, the average initial amount of water was 36.6%, in the dried state the average amount of water was 31.2%.
Ključne besede: weight, drying methods, splitting firewood, oak, stacking methods
Objavljeno v DiRROS: 09.04.2024; Ogledov: 71; Prenosov: 29
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4. Pedunculate oak (Quercus robur L.) in Bosnia and Herzegovina - state and perspectivesMirzeta Memišević Hodžić, Dalibor Ballian, 2023, izvirni znanstveni članek Povzetek: Bosnia and Herzegovina is located in Southeast Europe, and more than half its area of 51.129 km² belongs to forests and forest lands. 93% of the forests of Bosnia and Herzegovina are natural forests and have many plant species, many of which are endemic. There are eight oak species growing in Bosnia and Herzegovina. The most important ones are Quercus robur (despite being almost extinct due to overexploitation during the late XIX and early XX century), and Quercus petraea. Pedunculate oak in Bosnia and Herzegovina is found in mixed stands with common hornbeam and in pure stands under exceptional conditions, with a total area of about 30,000 ha. In this paper, the data of the studies carried out in the pedunculate oak forests of Bosnia and Herzegovina were compiled and a general evaluation was made. The results of phenological observation in pedunculate oak provenance test in Bosnia and Herzegovina through the years showed statistically significant differences among provenances in the beginning, end and duration of individual phenological phases. Researches on growth showed overtaking of provenances through the years, and best results in provenance Jelah for the most of investigated years. The research results on showed a significant positive correlation between the height and root collar diameter in provenance test and most of the investigated .The remaining pedunculate oak populations in Bosnia and Herzegovina have a good genetic structure and can be used as a seed stands for collecting seed material and producing seedlings for afforestation with this species
Ključne besede: Pedunculate oak, Bosnia and Herzegovina, afforestation
Objavljeno v DiRROS: 25.03.2024; Ogledov: 70; Prenosov: 53
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6. Preliminary assessment of genetic gain through the selection of different pedunculate oak populations in provenance testDalibor Ballian, Mirzeta Memišević Hodžić, 2022, izvirni znanstveni članek Povzetek: The distribution of pedunculate oak in Bosnia and Herzegovina is important in connecting the southern and eastern provenances of the Balkan Peninsula with provenances from Central Europe. However, due to over-exploitation, pedunculate oak is almost extinct in Bosnia and Herzegovina. This research aims to determine the heredity and production potential of the pedunculate oak from 28 provenances in the Bosnian-Herzegovinian provenance test through the genetic gain of thickness and height growth. The results will be used in selection of best provenances in terms of genetic gain. For this research, height and root collar diameter of pedunculate oak plants in Bosnian-Herzegovinian provenance tests were measured in 2012, 2016 and 2020. The provenance test was established in 2009. It contains 28 provenances from Bosnia and Herzegovina. Heredity and selection differentialwere assessed using analysis of variance. Possible genetic gain if using five best and one best provenance were determined. The results of the genetic gain for height obtained using data from 2012 and 2020 were low. The results obtained for 2016 indicate that the genetic gain for height, using five best provenances would be 7.62%, and using the best provenance 9.98%. Results of the genetic gain for root collar diameter obtained for 2016 and 2020 were low. For2012, the genetic improvement using five best provenances would be 4.28%, and using the best provenance 6.32%. The results indicate that by selecting the best provenances of pedunculate oak and their propagation, we can achieve a significant increase in plant height and thickness, i.e., the yield of wood mass. As research concerns juvenile material, it is necessary to continue systematic monitoring, to determine the actual heredity and genetic age, when the trees reach their physiological maturity, and when the annual value oscillations become uniform
Ključne besede: Pedunculate oak, genetic gain
Objavljeno v DiRROS: 08.03.2023; Ogledov: 378; Prenosov: 144
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7. Where to search: the use of opportunistic data for the detection of an invasive forest pestMaarten De Groot, Nikica Ogris, Mark van der Meij, Michael J.O. Pocock, 2022, izvirni znanstveni članek Povzetek: Early detection is important for the management of invasive alien species. In the last decade citizen science has become an important source of such data. Here, we used opportunistic records from the “LIFE ARTEMIS” citizen science project, in which people submitted records from places where they observed tree pests, to understand the distribution of a rapidly-spreading forest pest: the oak lace bug (Corythucha arcuata) in Slovenia. These citizen science records were not distributed randomly. We constructed a species distribution model for C. arcuata that accounted for the biased distribution of citizen science by using the records of other tree pests and diseases from the same project as pseudo-absences (so-called constrained pseudo-absences), and compared this to a model with pseudo-absences selected randomly from across Slovenia. We found that the constrained pseudo-absence model showed that C. arcuata was more likely to be found in east, in places with more oak trees and at lower elevations, and also closer to highways and railways, indicating introduction and dispersal by accidental human transport. The outputs from the model with random pseudo-absences were broadly similar, although estimates from this model tended to be higher and less precise, and some factors that were significant (proximity to minor roads and human settlements) were artefacts of recorder bias, showing the importance of taking the distribution of recording into account wherever possible. The finding that C. arcuata is more likely to be found near highways allows us to design advice for where future citizen science should be directed for efficient early detection.
Ključne besede: Oak lace bug, ecological modelling, citizen science, invasive alien species, early detection, Corythucha arcuata
Objavljeno v DiRROS: 08.09.2022; Ogledov: 494; Prenosov: 248
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8. Genetic variability of pedunculate oak (Quercus robur L.) at the Mediterranean margin of the distribution rangeMirzeta Memišević Hodžić, Barbara Fussi, Dušan Gömöry, Dalibor Ballian, 2021, pregledni znanstveni članek Povzetek: In Bosnia and Herzegovina, pedunculate oak (Quercus robur L.) occurs at the southern margin of its distribution range, close to the glacial refugia of this species. To assess the patterns of genetic diversity distribution at the rear edge of the Holocene colonization, we studied genetic variation in 20 pedunculate oak populations using 14 allozyme loci. Despite considerable differences among populations, neither the numbers of alleles nor genetic diversity showed any geographical trend within the studied area, although small isolated populations showed generally lower allelic richness. The Bayesian analysis of population structure indicated a kind of geographical pattern. We identified no signs of a recent bottleneck. The proximity to multiple glacial refugia explains the outcomes.
Ključne besede: pedunculate oak, allozyme, genetic variability, marginal populations, rear edge
Objavljeno v DiRROS: 22.07.2022; Ogledov: 522; Prenosov: 251
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9. Climatic regulation of leaf and cambial phenology in Quercus pubescens : their interlinkage and impact on xylem and phloem conduitsJožica Gričar, Jernej Jevšenak, Polona Hafner, Peter Prislan, Mitja Ferlan, Martina Lavrič, Dominik Vodnik, Klemen Eler, 2022, izvirni znanstveni članek Povzetek: Increased frequency and severity of stressful events affects the growth patterns and functioning of trees which adjust their phenology to given conditions. Here, we analysed environmental effects (temperature, precipitation, VPD and SWC) on the timing of leaf phenology, seasonal stem radial growth patterns, and xylem and phloem anatomy of Quercus pubescens in the sub-Mediterranean in the period 2014%2019, when various adverse weather events occurred, i.e. spring drought in 2015, summer fire in 2016 and summer drought in 2017. Results showed that the timings of leaf and cambium phenology do not occur simultaneously in Q. pubescens, reflecting different environmental and internal constraints. Although year-to-year variability in the timings of leaf and cambial phenology exists, their chronological sequence is fairly fixed. Different effects of weather conditions on different stages of leaf development in spring were observed. Common climatic drivers (i.e., negative effect of hot and dry summers and a positive effect of increasing moisture availability in winter and summer) were found to affect the widths of xylem and phloem increments with more pronounced effect on late formed parts. A legacy effect of the timing of leaf and cambial phenology of the previous growing season on the timing of phenology of the following spring was confirmed. Rarely available phloem data permitted a comprehensive insight into the interlinkage of the timing of cambium and leaf phenology and adjustment strategies of vascular tissues in Mediterranean pubescent oak to various environmental constraints, including frequent extreme events (drought, fire). Our results suggest that predicted changes in autumn/winter and spring climatic conditions for this area could affect the timings of leaf and stem cambial phenology of Q. pubescens in the coming years, which would affect stem xylem and phloem structure and hydraulic properties, and ultimately its performance.
Ključne besede: pubescent oak, leaf development, radial growth, initial earlywood vessel, sieve tube, anatomy, cambial cell production, extreme weather events
Objavljeno v DiRROS: 06.09.2021; Ogledov: 972; Prenosov: 288
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10. 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, izvirni znanstveni članek Povzetek: 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.
Ključne besede: ozone, gas exchange, English oak, holm oak, downy oak, Quercus ilex L., Quercus robur L., Quercus pubescens Willd
Objavljeno v DiRROS: 11.08.2020; Ogledov: 1757; Prenosov: 1079
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