Quercus Frainetto Research Articles

Chemo-sensory characterization of aroma active compounds of native oak wood in relation to their geographical origins

Oak wood contains aroma-active compounds that contribute significantly to the chemical structure, olfactory and gustatory qualities of alcoholic beverages and vinegars as by-products that have been either fermented and/or aged in oak barrels. The chemical composition of cooperage oak is highly variable, depending on the degree of toasting and natural seasoning. However, it is unclear whether the odor of oak varies according to different geographical regions and pedoclimatic conditions. Especially in view of the actual challenges in forestry in relation to climate change, the present study aimed at elucidating the odorous constituents of nine natural oak samples from Germany, Austria and Hungary with respect to these influencing parameters. The odor profiles of the oaks were compared, the potent odorants were determined, and selected odorants were quantified using stable isotope dilution assays (SIDA). The majority of the identified odorants in all samples were fatty acid degradation products, followed by a series of odorants with terpenoic structure and others resulting from the degradation of lignin. Several different odorants including 2-propenoic acid and cinnamaldehyde are reported here for the first time in oaks from different growth regions. Odor activity values (OAVs), calculated based on odor thresholds (OTs) in water, revealed hexanal, (E)-2-nonenal, (Z)-3-hexenal, eugenol, vanillin, and whiskey lactone as potent odorants for the oak odor. Principal component analysis of the data obtained from sensory evaluation, comparative aroma extract dilution analysis (cAEDA) and their corresponding quantified odorants showed that the highest separation rate was obtained for Hungarian oak, whereas Austrian and Bavarian oak samples were more similar. Recombination experiments by mixing the dominant odorants in their naturally occurring concentrations revealed a good agreement of the smell properties of the model mixture with the smell of the respective original sample. These findings aimat evaluating and establishing a better understanding of the distinctive smell of oak wood and demonstrated the prospects of new oak sources.

Bark thickness models for oak forests being converted from coppice to high forests in Northwestern Turkey.

The research was carried out in the coppice-originated pure oak stands that are being converted to high forests in northwest Turkey. The main goal of the research was to determine the bark thickness (BT) based on tree variables, such as tree diameter at breast height (DBH), total tree height (H), crown diameter (CD), and age (AGE) of the stem sections taken from a total of 350 trees that were destructively sampled from different sites, different oak species (Quercus petraea, Quercus frainetto, Quercus cerris), and different development stages. Models were developed with stepwise multiple regression analysis to predict BT based on the variables.For all oak species, all models obtained by stepwise multiple regression analysis were found to be significant at p = 0.001 level. In Quercus petraea, only the DBH-dependent model explained the variation in BT at a rate of 73%, estimating with an absolute error rate of 21%. The fit statistics of the models (based on DBH and DBH-H explanatory variables) obtained for Quercus frainetto are very close to each other, and they explained the variation in BT at a rate of 69% and estimated with an error rate of 26%. Models (based on DBH and DBH-H explanatory variables) explain the variation in BT in Turkey oak at a rate of 91%, indicating species-specific results. The models based on only DBH can be used with high accuracy to estimate BT.

Unequivocal Differences in Predation Pressure on Large Carabid Beetles between Forestry Treatments

Carabid beetles (Coleoptera: Carabidae) are considered as one of the most cardinal invertebrate predatory groups in many ecosystems, including forests. Previous studies revealed that the predation pressure provided by carabids significantly regulates the ecological network of invertebrates. Nevertheless, there is no direct estimation of the predation risk on carabids, which can be an important proxy for the phenomenon called ecological trap. In our study, we aimed to explore the predation pressure on carabids using 3D-printed decoys installed in two types of forestry treatments, preparation cuts and clear cuts, and control plots in a Hungarian oak–hornbeam forest. We estimated the seasonal, diurnal and treatment-specific aspects of the predation pressure on carabids. Our results reveal a significantly higher predation risk on carabids in both forestry treatments than in the control. Moreover, it was also higher in the nighttime than daytime. Contrarily, no effects of season and microhabitat features were found. Based on these clues we assume that habitats modified by forestry practices may act as an ecological trap for carabids. Our findings contribute to a better understanding of how ecological interactions between species may change in a modified forest environment.

Conservation of forest genetic resources through the example of native Quercus species from the “Košutnjak” park forest in Serbia

Given the importance of urban park forests and protected natural areas in the urban environment, the implementation of the concept of genetic conservation is one of the main ways to save and improve this category of natural resources. Forests such as Košutnjak can be considered a refuge for flora and fauna and by establishing conservation programs for certain species, the entire ecosystem would be better protected. The purpose of this paper is to elaborate a systematic approach to in situ conservation of forest genetic resources in urban areas through the example of four native oak species: pedunculate oak, sessile oak, Hungarian oak and downy oak in the protected natural area “Košutnjak” in the capital of Serbia – Belgrade, to develop replicable conservation guidelines for urban park forests. The methodological framework for the development of guidelines for genetic conservation, presented in this paper, is a replicable model whose basic principles can be applied in other cases of urban park forests.

New dendroclimatological research in oak, S (Quercus Frainetto Ten.) forestry in Šumadija-Region- (Central Serbia) as a basis for climate change monitoring

New dendroclimatological research in oak, S (Quercus Frainetto Ten.) forestry in Šumadija-Region- (Central Serbia) as a basis for climate change monitoring

New dendroclimatological research in oak, S (Quercus Frainetto Ten.) forestry in Šumadija-Region- (Central Serbia) as a basis for climate change monitoring

In this work present study to describe the survey of climatic change in the case in Šumadija-Central Serbia. Climate change due to a fragile ecosystem in semi-arid, and arid region such as Serbia is one of the most challenging climatological and hydrological problems. Dendrochronology, wich uses tree rings to their exact year of formation to analyse temporal and spatial patterns of processes in the physical and cultural sciences, can be used to evaluate the effects of climate change. In this study, the effects of climate change werw simulated using dendrochronology (tree rings) and an artificial neural network (ANN) for the period from 1900—2015. The present study was executed using the (Quercus frainetto Ten.). Tree rings width, temperature and precipitation were the input parameters for the study, and climate change parameters were the outputs. After the training process, the model was verified. The verified network and tree rings were used to simulate climatic parameter changes during the past times. The results showed that the integration of dendroclimatology and an ANN renders a high degree of accuracy and efficiency in the simulation of climatic change. The results showed that the climatic of the study area changed from semiarid, to arid, and its annual precipitation decreased significantly.

Factors Influencing the Oak Lace Bug (Hemiptera: Tingidae) Behavior on Oaks: Feeding Preference Does not Mean Better Performance?

Oak lace bug - Corythucha arcuata (Say, 1832) (Hemiptera: Tingidae) is a North American species that has been introduced to Europe and Asia, where it became a serious oak pest. As little is known about its behavior, we conducted a study in which we tested the preference and performance of the oak lace bug for different oak species and the influence of powdery mildew and CO2 on the behavior of the oak lace bug. Four of the most represented oak species in Serbia (Hungarian, pedunculate, sessile, and Turkey oak) were used for testing the preference and performance of the oak lace bug, and the influence of oak powdery mildew on the behavior of the oak lace bug. The influence of CO2 on the behavior of the oak lace bug was tested on pedunculate oak. The results of this study have shown that there are differences in preference and performance of the oak lace bug between the analyzed oak species; there are significant differences in the oak lace bug host preference in the laboratory and in field conditions; Hungarian oak is most threatened by the oak lace bug, as the oak lace bug performs best on this species and preferers this species in field conditions; the oak powdery mildew and oak lace bug are in an antagonistic relationship; and that the changes in the leaves caused by the expected increase in CO2 concentration in the future will probably not influence the feeding behavior of the oak lace bug adults.

Patterns and drivers of deadwood quantity and variation in mid-latitude deciduous forests

Deadwood is a fundamental forest habitat component and highly important for biodiversity conservation. Its availability, composition, size, categories and distribution depend on various structural and environmental factors (e.g., forest age, management, tree mortality, climate, decomposition). We analysed deadwood patterns along altitudinal gradients of managed (three) and unmanaged (one) deciduous forests in Western Romania. A total of 153 plots (119 managed, 34 unmanaged) of four pre-classified forest types dominated by Fagus sylvatica, Quercus petraea, Quercus frainetto with Quercus cerris, and Tilia tomentosa were evaluated, the former two both in managed and unmanaged stands.The managed forest types displayed an average deadwood volume of 47 m3 ha−1 with lying deadwood accounting for over 70%. About 40% of deadwood objects occurred in the early to intermediate decomposition stage. Deadwood volumes in unmanaged forest types exceeded those of managed forests two- to threefold although the deadwood amounts observed in managed forests were similar to low-intervention or recently abandoned forests, lying within critical threshold values considered important for the long-term preservation of biodiversity. Linear-mixed-effects models confirmed the positive impact of non-management and the negative effect of annual mean temperature on deadwood volume. Prediction models suggested that management and annual mean temperature showed additive effects, indicating that a combination of environmental and structural parameters determines the amount of deadwood in the studied forest types. As climatic variables strongly influence tree species composition and thus forest type, management involving deadwood retention or accumulation should consider forest-type specific characteristics and thresholds.

First Report on the Acrobat Ant Crematogaster scutellaris Storing Live Aphids in Its Oak-Gall Nests.

Simple SummaryGalls represent an amazing microcosm which contains a variety of multiple interactions among different actors, and therefore, offers the opportunity to observe and investigate phenomena belonging to different areas of biology: from the development process, connected to the interaction between the galligenous agent and the host plant, to the moment of their colonization by different species, since some ants may provide defense against pathogens, certain phytophagous insects or favor mutualists. In the present work we describe some aspects of oak-gall colonization by different ant species, highlighting how the gall’s height on the plant influences ant colonization and how different ant species produce different nest architectures. The most relevant aspect, however, is the discovery of a novel ant-aphid relationship: the transport of living aphids into oak-gall nests. We found no evidence of immediate predation of these aphids inside the galls, so they are likely stored to overwinter due to a mutualistic relationship and/or serve as food storage. This is not only an interesting report on the mutualisms involving ants and their insect partners, but it may also have important consequences on the aphids’ phenology with the host plants. Once more, ants show their relevant impact on multitrophic interactions and ecosystem dynamics.This study provides new data about the role of ants in mutualistic interactions with aphids mediated by galls. We focused our investigation on galls induced by the cynipid Andricus kollari by conducting a survey and a subsequent experiment in an Italian oak forest. The ants Crematogaster scutellaris, Colobopsis truncata and Temnothorax italicus frequently used the galls as nests: Crematogaster scutellaris occupied galls which were located higher on the oak trees, while C. truncata and T. italicus were located at lower positions. In addition, galls occupied by C. scutellaris showed varied internal architecture in relation to the colony composition. Importantly, field surveys revealed for the first time that C. scutellaris nest galls also contained live individuals of the non-galligenous aphid Panaphis juglandis. Field experiments suggested that the ants actively seek, collect and stock live aphids. No signs of predation and injuries were detected on the stored aphids, which were probably kept for safe overwintering, though we cannot exclude a possible occasional use as food. This report reveals a possible novel relationship which could have important consequences on the phenology and presence of aphids on the host plant.

Thinning effects on biomass and element concentrations of roots in adjacent hornbeam and oak stands in Istanbul, Turkey

BackgroundThinning is a commonly used treatment in forest management which affects the tree root systems. The effects of thinning on element concentrations and seasonal change of roots were evaluated in adjacent oak (Quercus frainetto Ten.) and hornbeam (Carpinus betulus L.) stands according to the different root diameter classes.MethodTwo replicated control and thinning plots (50 m × 50 m) were set for each species (hornbeam and oak). Thinning treatments (November 2010) reduced 50% of the basal area in both oak and hornbeam stands. Roots were assessed by seasonal collection over 2 years (from October 2010 to October 2012). The roots were then sorted into diameter classes of 0–2 mm (fine roots), 2–5 mm (small roots) and > 5 mm (coarse roots). C, N, P, K, Ca, Na, Mg, S, Mn, Fe, Al, Zn, Pb, Ni, Cu and Cd were analyzed.ResultsExcept coarse roots, the highest root biomasses were determined in April-2011 in all plots. Fine-root biomass in oak was found significantly higher in control plots. In contrast to the oak, the fine-root biomass in the thinned hornbeam plots was higher than in the controls. The small-root biomass did not significantly differ between the thinned and the control plots in both oak and hornbeam stands. However, the coarse-root biomass showed significant differences between the control (1989 g∙m− 2) and thinned plots (1060 g∙m− 2) in oak, while no difference was detected in hornbeam. The concentrations of C, Al, Pb, Cd, Ni, Zn, Mn, Na, K, Mg and P in the fine roots of oak were significantly higher in the thinned plots. However, the concentration of Pb, Cd and Fe in the fine roots was significantly higher in the thinned plots of hornbeam. Significant differences were observed between the species for all elements in the fine roots except for C, N and P. In particular, elements in the fine roots tended to increase in July in the oak. In the hornbeam, all element concentrations in the fine roots (except C, N, and S) in the thinned plots showed a tendency to increase in April. The concentrations of Pb, Ni, Al, Fe, Cu, Ca, Na, K, Mg and P in the hornbeam control plots increased during the April 2011 period.ConclusionThe results indicated that thinning effects on temporal changes and concentrations of elements in the roots could be attributed to species-specific characteristics.

Varijabilnost sladuna (Quercus frainetto Ten.) sa područja Lipovice prema morfološkim svojstvima sadnica

Natural populations of Hungarian oak in Serbia are found near the northwestern boundary of the range of distribution of this significant forest species. The survival of forest border provenances is endangered due to climate change, small population size, low species competitiveness, etc. Therefore, ancillary measures of population regeneration support are recommended along with broadening of their genetic diversity. Although the knowledge of the levels and structure of genetic diversity of populations is a prerequisite for successful conservation and use, research of this topic regarding Hungarian oak is rare. The analyses of morphological traits of one-year-old seedlings of 40 half-sib families are carried out in order to gain insight into the variability of Hungarian oak population in Lipovica. The intrapopulation variability was determined based on two measured morphological parameters and one derived ratio. The obtained results show there is a significant variability of morphological traits of seedlings on the level of half-sib families and they indicate a high phenotypic variability of the researched traits. The results of the analysis of variance show statistically significant differences between the researched halfsib families for all observed traits. The researched gene pool of Hungarian oak is characterized by a satisfactory degree of genetic variability and represents a good starting point for the process of further breeding. In order to confirm the results of this research, i.e., to determine more precisely genetic structure of the population, it is necessary to perform analyses of various phenotypic traits in specially designed field plantations as well as the analysis of adequate DNA markers.

Najzastupljenije vrste insekata defolijatora lišćarskih šuma u okviru praćenja na BIT nivo-a I u 2021. godini

In order to make conclusions related to the selection of the most appropriate improvement measures, it is necessary to define the condition of forests through monitoring their health state. ICP for Forests Monitoring deals with human factors (mainly air pollution) and biotic factors that impair vitality and hinder the development of forest ecosystems in Europe and Serbia. Since broadleaved forests experience stronger attacks of plant diseases and pests, they have more severe defoliation. Beech is the most common broadleaved species at the ICP sample plots in Serbia. It is followed by oak species - sessile oak, Turkey oak and Hungarian oak. The largest number of insect species develop on the assimilation organs of forest trees. The paper presents the most common species of defoliators detected at SP in Serbia in 2021.

Syntaxonomy of Hungarian oak (Quercus frainetto Ten.) forests in Eastern Romania (Moldavia)

Syntaxonomy of Hungarian oak (Quercus frainetto Ten.) forests in Eastern Romania (Moldavia)

Short Term Impacts of Harvesting 0perations on Soil Chemical Properties in a Mediterranean Oak Ecosystem

Soil physical and chemical properties can be seriously affected by forest operations. There is a knowledge gap on this topic for oak ecosystems, which can play a significant role in the context of multiple-use forestry. The main objective of this study was to analyse forest floor and topsoil changes (0–10 cm) two years after the application of small-scale thinning (50% reduction of basal area) and clear-cut operations using mules to carry harvested material in a Northern Greece oak (Quercus frainetto Ten)ecosystem. The total amount of forest floor (O1+O2 horizons) was reduced by 37.8% in the thinned and 30.8% in the clear-cut plots compared to control plots. These large reductions are mainly due to reduction in the O2 horizon in the treated plots. Decomposition was reduced in the treated plots, possibly due to the new drier conditions. Treatments increased the soil pH but not to a significant extent. No evidence of erosion was found in the experimental plots due to the protective function of the forest floor and the use of designated mule trails. The areal extent of soil compaction was limited to only 3% of the total area mainly due to the careful planning and implementation of animal skidding. Small differences in C (%) and Ν (%) were found among control, thinned and clear-cut plots. The limiting growth factors in Mediterranean oak ecosystems are soil depth and the seasonal change of soil moisture, especially during the summer dry period. More research on the definition of the optimum thinning degree and extraction systems in similar ecosystems will be important to satisfy the need to improve soil characteristics.

The Impact of Climate Change on the Appearance of Some Pathogens in Oak Forests (Quercus frainetto Ten.) and the Analysis of Thickness Increase in the Šumadija Region (Central Serbia)

Abstract Climate change is becoming increasingly frequent. This paper presents the relationship between climate change and the appearance of certain pathogens in oak forests in area Šumadija (central Serbia). The aim of the work is based on experimental sample of land, to carry out research in healthy and infected oak forests and to determine the effect of pathogenic fungi: Microsphera alphitoides and Ophiostoma quercus Armillaria mellea, and the impact in growth in oak forests. Research was conducted on three experimental fields. One pathogen was identified in each experimental field. The effect of fungi is followed by a different soil depth, and in the root zone in oak forests. Furthermore, our goal was to reveal the behavior of fungi in old and young oak forests. The tests were done on nutritive substrates and land suspensions. The research yielded satisfactory definite results, that will be the basis for further monitoring and research.

How will a drier climate change carbon sequestration in soils of the deciduous forests of Central Europe?

Global warming is accompanied by increasing water stress across much of our planet. We studied soil biological processes and changes in soil organic carbon (SOC) storage in 30 Hungarian oak forest sites in the Carpathian Basin along a climatic gradient (mean annual temperature (MAT) 9.6–12.1 °C, mean annual precipitation (MAP) 545–725 mm) but on similar gently sloped hillsides where the parent materials are loess and weathered dust inputs dating from the end of the ice age. The purpose of this research was to understand how a drying climate, predicted for this region, might regulate long-term SOC sequestration. To examine the effects of decreasing water availability, we compared soil parameters and processes in three categories of forest that represented the moisture extremes along our gradient and that were defined using a broken-stick regression model. Soil biological activity was significantly lower in the driest (“dry”) forests, which had more than double the SOC concentration in the upper 30 cm layer (3.28 g C/100 g soil ± 0.11 SE) compared to soils of the wettest (“humid”) forests (1.32 g C/100 g soil ± 0.09 SE), despite the fact that annual surface litter production in humid forests was ~ 37% higher than in dry forests. A two-pool SOM model constrained to fit radiocarbon data indicates that turnover times for fast and slow pools are about half as long in the humid soil compared to the dry soil, and humid soils transfer C twice as efficiently from fast to slow pools. Enzyme activity and fungal biomass data also imply shorter turnover times associated with faster degradation processes in the soils of humid forests. Thermogravimetry studies suggest that more chemically recalcitrant compounds are accumulating in the soils of dry forests. Taken together, our results suggest that the predicted climate drying in this region might increase SOC storage in Central European mesic deciduous forests even as litter production decreases.

Mesophilous Quercus frainetto Dominated Forests from Western Balkans

Hungarian oak (Quercus frainetto) has dominant or co-dominant role in many thermophilous deciduous forest communities in the Balkan Peninsula. However, recent field research in the north-western margin of its range has revealed that some stands have a pronounced mesophilous character, which was also supported by data from the literature. This paper aims to analyze this mesophilous community of Hungarian oak which is found in north-western Serbia, north-eastern Bosnia and Herzegovina (B&H) and eastern Croatia. Numerical analysis, which included classification and ordination of all 474 available relevés of Hungarian oak forests from the western and central Balkans, along with the 43 relevés of mesophilous forests of oak-hornbeam from B&H, have shown that 83 mesophilous Hungarian oak relevés are floristically and ecologically more similar to mesophilous forests of sessile oak-hornbeam (Erythronio-Carpinion) than to xero-thermophilous forests of Qeurcion confertae. The new association Carpino betuli-Quercetum frainetto ass. nova hoc loco was described, floristically and ecologically characterized and assigned to mesophilous oak-hornbeam forests of Erythronio-Carpinion. The study also discusses the syntaxonomical issues of Quercion confertae and its central association Quercetum frainetto-cerridis, considering the problem of the lack of good diagnostic species for both syntaxa, and introduces possible ways of dealing with these issues.

General regularities of height-diameter curves in Hungarian oak, sessile oak and Turkey oak high forests

The height-diameter curves of natural even-aged Hungarian oak, sessile oak and Turkey oak forests in the regions of Staro Oryahovo, Sherba, Tsonevo and Aytos Forestry Districts have been studied. In order to explore the shape of the curves and, in particular, their steepness, the steepness index SI of Douhovnikov (“the method of natural indicators”) was applied. The curves were divided into three groups according to it: flat curves, medium steep curves and steep curves. Both the traditional height-diameter curves and the corresponding relative curves of Tyurin were studied. Consideration of the traditional height-diameter curves gives a certain ground for investigating to-gether the height-diameter curves of Hungarian oak and sessile oak, disregarding the tree species. This inference was confirmed by comparing the relative height-diameter curves for Hungarian oak, sessile oak and Turkey oak with Tyurin’s uniform curve of relative heights. For these comparisons we used the Willcoxon test. A statistically significant great proximity in their shapes was found. As a uniform average curve of relative heights has been established for all tree species, this proximity indicates a possibility of creating a single fan of height-diameter curves for high Hungarian, sessile and Turkey oak.

Quercus frainetto honeydew honey from Croatia: composition and properties

Quercus frainetto honeydew honey production is characteristic of the geographical region of Požega valley, Croatia. This honeydew honey is produced in a specific way, from sweet fruit sap formed at the place where green acorns were discarded, without the mediation of plant sucking insects. The aim of this study was to determine physicochemical parameters, antioxidant capacity, multielement profile, melissopalynological and sensory analysis of this specific honey type. The results showed that Q. frainetto honeydew honey is characterised with high free acidity (51.7 ± 5.5 mmol/kg), negative specific rotation (−8.9 ± 2.0), and dark colour (122 ± 15 mm Pfund). It possesses high phenolic content (507.6 ± 71.8 mg gallic acid/kg) as well as high antioxidant capacity determined by FRAP (1093.9 ± 84.7 µM Fe(II)) and DPPH assay (IC50 3.55 ± 0.48 mg/mL). From analysed macro and micro elements, high manganese content (33.038 ± 6.053 mg/kg) should be noted. The sensory profile is characteristic of honeydew honey with emphasised acidity and persistence/aftertaste.

New or rarely reported lichens for Thraki, Greece II

Christensen S.N. 2018: New or rarely reported lichens for Thrace, Greece. – Herzogia 31: 390–394.Forty five species are reported from Thrace. Tree taxa, Cladonia caespiticia, Dermatocarpon luridum, and Vahliella leucophaea, are new to the Greek mainland, and 34 taxa are new to Thrace. This is at the same time a first record of lichens on Quercus frainetto in Greece.