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Iskalni niz: "ključne besede" (oak) .

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A study of important entomofauna in oak forests of Slovenia
Miroslav Harapinov, Maja Jurc, 2000

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: 1297; Prenosov: 261
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Morfološka analiza puhastega hrasta (Quercus pubescens Willd.) v Sloveniji
Mateja Jerše, Franc Batič, 2007

Povzetek: Z raziskavo smo poskusili ovrednotiti morfološke raznolikosti puhastega hrasta(Quercus pubescens Willd.) v Sloveniji. Raznolikost je posledica pestrosti rastišč in možnosti križanja z drugimi vrstami hrastov. Rezultati analize so bili dobljeni na osnovi meritev in opazovanja listov, plodov in kratkih poganjkov puhastegarasta, vzorčenih v osmih populacijah po Sloveniji. Na posamezni lokaciji je bilo izbranih do pet dreves in na posameznem drevesu nabranih do sto listov s kratkih poganjkov v osvetljenem delu krošnje. Na osebkih s plodovi so bili nabrani tudi plodovi. V laboratoriju je bilo na listih izmerjenih, ocenjenih in izračunanih 13 parametrov, na plodovih in kratkih poganjkih pa po en parameter. Uporabljene so bile deskriptivne, univariatne in multivariatne statistične metode za izvrednotenje rezultatov. Analize morfoloških parametrov so pokazale značilne razlike tako med posameznimi osebki v populacijah kot med populacijami. Ugotovljeno je bilo tudi, da vrsto Q. virgiliana (Ten.) Ten. lahko obravnavamo znotraj vrste Q. pubescens.
Ključne besede: puhasti hrast, Quercus pubescens Willd., Quercus virgiliana (Ten.), morfologija, listi, plodovi, Slovenija, oak, morphology, leaf, fruit, Slovenia
DiRROS - Objavljeno: 12.07.2017; Ogledov: 1408; Prenosov: 320
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Isotopic and water relation responses to ozone and water stress in seedlings of three oak species with different adaptation strategies
Claudia Cocozza, Tom Levanič, Saša Zavadlav, Tanja Mrak, Elena Paoletti, Yasutomo Hoshika, Alessio Giovannelli, Hojka Kraigher, 2020

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
DiRROS - Objavljeno: 11.08.2020; Ogledov: 9; Prenosov: 4
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Post-fire effects on development of leaves and secondary vascular tissues in Quercus pubescens
Jožica Gričar, Polona Hafner, Martina Lavrič, Mitja Ferlan, Nives Ogrinc, Bor Krajnc, Klemen Eler, Dominik Vodnik, 2020

Povzetek: An increased frequency of fire events on the Slovenian Karst is in line with future climate-change scenarios for drought-prone environments worldwide. It is therefore of the utmost importance to better understand tree-fire-climate interactions for predicting the impact of changing environment on tree functioning. To this purpose, we studied the post-fire effects on leaf development, leaf carbon isotope composition (%13C), radial growth patterns and the xylem and phloem anatomy in undamaged (H-trees) and fire-damaged trees (F-trees) of Q. pubescens with good re-sprouting ability in spring 2017, the growing season after a rangeland fire in August 2016. We found that the fully developed canopy of F-trees reached only half of the LAI values measured in H-trees. Throughout the season, F-trees were characterised by higher water potential and stomatal conductivity and achieved higher photosynthetic rates compared to unburnt H-trees. The foliage of F-trees had more negative %13C values than those of H-trees. This reflects that F-trees less frequently meet stomatal limitations due to reduced transpirational area and more favourable leaf-to-root ratio. In addition, the growth of leaves in F-trees relied more on the recent photosynthates than on reserves due to the fire disturbed starch accumulation in the previous season. Cambial production stopped 3 weeks later in F-trees, resulting in 60% and 22% wider xylem and phloem increments, respectively. A novel approach by including phloem anatomy in the analyses revealed that fire caused changes in conduit dimensions in the early phloem but not in the earlywood. However, premature formation of the tyloses in the earlywood vessels of the youngest two xylem increments in F-trees implies that xylem hydraulic integrity was also affected by heat. Analyses of secondary tissues showed that although xylem and phloem tissues are interlinked changes in their transport systems due to heat damage are not necessarily coordinated.
Ključne besede: pubescent oak, cambium, radial growth, xylem, phloem, anatomy, sub-Mediterranean
DiRROS - Objavljeno: 19.03.2020; Ogledov: 294; Prenosov: 141
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Inter-individual variability in spring phenology of temperate deciduous trees depends on species, tree size and previous year autumn phenology
Lorène Julia Marchand, Inge Dox, Jožica Gričar, Peter Prislan, Sebastien Leys, Jan Van den Bulcke, Patrick Fonti, Holger Lange, Erik Matthysen, Josep Peñuelas, Paolo Zuccarini, Matteo Campioli, 2020

Povzetek: We explored the inter-individual variability in bud-burst and its potential drivers, in homogeneous mature stands of temperate deciduous trees. Phenological observations of leaves and wood formation were performed weekly from summer 2017 to summer 2018 for pedunculate oak, European beech and silver birch in Belgium. The variability of bud-burst was correlated to previous' year autumn phenology (i.e. the onset of leaf senescence and the cessation of wood formation) and tree size but with important differences among species. In fact, variability of bud-burst was primarily related to onset of leaf senescence, cessation of wood formation and tree height for oak, beech and birch, respectively. The inter-individual variability of onset of leaf senescence was not related to the tree characteristics considered and was much larger than the inter-individual variability in bud-burst. Multispecies multivariate models could explain up to 66% of the bud-burst variability. These findings represent an important advance in our fundamental understanding and modelling of phenology and tree functioning of deciduous tree species.
Ključne besede: leaf unfolding, wood formation, coloration, Pedunculate oak, European beech, Silver birch
DiRROS - Objavljeno: 10.06.2020; Ogledov: 160; Prenosov: 77
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Timeline of autumn phenology in temperate deciduous trees
Inge Dox, Jožica Gričar, Lorène Julia Marchand, Sebastien Leys, Paolo Zuccarini, Charly Geron, Peter Prislan, Bertold Mariën, Patrick Fonti, Holger Lange, Josep Peñuelas, Jan Van den Bulcke, Matteo Campioli, 2020

Povzetek: Cessation of xylem formation or wood growth (CWG) and onset of foliar senescence (OFS) are key autumn phenological events in temperate deciduous trees. Their timing is fundamental for development and survival of trees, ecosystem nutrient cycling, the seasonal exchange of matter and energy between the biosphere and atmosphere and affect the impact and feedback of forests to global change. A large-scale experimental effort and improved observational methods have allowed us to compare the timing of CWG and OFS for different deciduous tree species in Western Europe, in particularly silver birch, a pioneer species, and European beech, a late-succession species, at stands of different latitudes, of different levels of site fertility, and for two years with contrasting meteorological and drought conditions i.e., the low-moderately dry 2017 and the extremely dry 2018. Specifically, we tested whether foliar senescence started before, after or concurrently with CWG. OFS and CWG occurred generally between late September and early November, with larger differences across species and sites for OFS. Foliar senescence started concurrently with CWG in most cases, except for the drier 2018 and, for beech, at the coldest site, where OFS occurred significantly later than CWG. Behavior of beech in Spain, the southern edge of its European distribution, was unclear, with no CWG, but very low wood growth at the time of OFS. Our study suggests that OFS is generally triggered by the same drivers of CWG or when wood growth decreases in late summer, indicating an overarching mechanism of sink limitation as a possible regulator of the timing of foliar senescence.
Ključne besede: autumn phenology, xylem formation, foliar senescence, cambium, chlorophyll, radial growth, wood, decidiuous trees, common aspen, common beech, pedunculate oak, silver birch
DiRROS - Objavljeno: 10.06.2020; Ogledov: 143; Prenosov: 118
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