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Key message: Early rewetting influenced growth variability and hydraulic uniformity in Pedunculate oak wood on disturbed peatland. Long-term study highlighted vessel widening's importance in adapting to water availability changes. Pedunculate oak (Quercus robur L.) is a widely recognized flood-tolerant tree that thrives on fertile and moist soil conditions, such as on or close to peatland ecosystems. In the frame of climate change counteracting policies, rewetting peatland ecosystems is gaining increasing interest, while the ecological consequences are not always clear. Whereas the effect of flooding on wood anatomical traits of pedunculate oak is widely documented, little is known about the effect of permanent rewetting. In this study, we investigated the wood anatomical responses of 12 pedunculate oak trees located on a formerly drained peatland in NE Germany, that experienced flooding and a consequent rewetting. Wood anatomical traits were analyzed via CARROT, a tool that employs the accuracy and efficiency of artificial intelligence to identify tree rings and vessels. Growth anatomical traits (e.g., tree ring width) showed a sudden increase after the rewetting started in 1995, while hydraulic traits (Dh and Ks) displayed a decreasing trend only after the rewetting process was fostered by the opening of an artificial canal in 2004. Variance analysis highlighted subtle changes in the trait's distribution over time: high soil water content triggered variability in the growth anatomical traits and, simultaneously, homogeneity in the hydraulic traits. Results suggest the relevance of the "vessel widening" mechanisms to develop coping strategies in response to the later stage of the rewetting, and pose relevant insights concerning the importance of specific site conditions for the implementation of rewetting policies in peatlands with presence of pedunculate oak. [ABSTRACT FROM AUTHOR]

Acorn production in oaks (Quercus spp.) shows considerable inter-annual variation, known as masting. The effects of pollen sourced from trees within or outside the stand on acorn production were investigated in pedunculate oak (Quercus robur L.) in an ancient mixed woodland during two moderate masting years. Comparisons were made between natural pollination, hand pollinations with out-of-stand pollen, in-stand pollen or a 1:1 combination of the two pollen sources, and for bagged flowers left unpollinated. After all treatments, > 85% of the flowers or developing acorns were aborted between May and August of both years. When flowers were protected with pollen bags and no pollen added, no acorns were produced. In contrast, hand pollination with out-of-stand pollen produced the most acorns both years and significantly more than within-stand pollen or natural pollination in 2022. Hand pollination with out-of-stand or within-stand pollen provided significantly more acorns than natural pollination in 2023. In 2022, hand pollination with a 1:1 mixture of out-of-stand and within-stand pollen yielded an intermediate number of mature acorns between those for the out-of-stand and within-stand pollination treatments. The study provides clear evidence of maternal choice during acorn development in pedunculate oak and of the benefits of pollen supplementation. It also confirms that pedunculate oak is a fruit-maturation masting species; abortion of pollinated flowers and immature acorns determines a mast year (rather than the number of flowers produced) at this site. [ABSTRACT FROM AUTHOR]

The emission of CO2 from soil represents one of the most significant fluxes between terrestrial ecosystems and the atmosphere. It is crucial to investigate the impact of stand age on soil CO2 emissions in order to evaluate the possibility of carbon sequestration through the establishment of new forests. In this study, soil CO2 emissions and microclimate variables (soil temperature and moisture) were investigated in the chronosequence of three differently aged stands (4-, 14-, and 70-year-old stands) in floodplain pedunculate oak (Quercus robur L.) forests in Serbia. This study highlights how the artificial regeneration of pedunculate oak forests (establishment of new stands) can affect CO2 emissions from soils. Seasonal fluctuations in soil CO2 emissions were observed in all of the monitored stands, along with variations in the influence of soil temperature and moisture. Multiple linear regression, incorporating soil temperature, soil moisture, and their interaction, offered the most comprehensive explanation for the variation observed in soil CO2 emissions. The seasons had statistically significant effects (p < 0.001) on CO2 emission from the soil in the examined stands during 2022. The youngest stand (4-year-old) had significantly higher soil CO2 emissions (p < 0.05) compared to the older stands over the entire study period (2021–2022). These results showed that the 70-year-old stand (natural high stand) had significantly lower soil CO2 emissions compared to the 4-year-old stand (artificially regenerated stand). [ABSTRACT FROM AUTHOR]

Clear-cutting is the most robust intervention in a forest ecosystem, causing marked changes in ecosystem processes. Although the effects of forest harvesting have been widely investigated, comparative studies can provide vital supplementary information concerning specific fields, including changes in soil microbiota structure and functioning. Our study examined the soil bacterial community composition, diversity, and activity of a mixed pedunculate oak stand over three years after clear-cutting based on 16S rRNA sequencing and substrate-induced respiration data. In addition, we conducted a yearly comparison with a control oak stand already in the regeneration phase. According to our results, the forest harvest caused only limited changes in the diversity, structure, and activity of the soil bacterial community of the oak stand, suggesting that soil parameters influence the soil bacterial community structure and functioning more significantly than the cessation of forest cover. [ABSTRACT FROM AUTHOR]

Enabling natural seed regeneration is important because natural stands grown from seeds are more productive compared to vegetative and artificial ones; they are also more resistant to adverse environmental factors and climate change. The aim of the study was to assess natural regeneration after clear-cutting in oak stands in the north-eastern Ukraine. The research was carried out in stands where regeneration cutting was carried out in years with different oak fruiting intensity. According to the recent inventory, the total regeneration quantity in clear-cut plots was from 16,800 to 28,900 stems ha–1, including 12,600–19,300 stems ha–1 of oak (60–85% of the total number), and a greater number of the regenerated oaks was recorded in the years of medium, good and very good acorn yield. It was established that the cutting must be carried out precisely in such years, preceded by pre-harvest cultural activities to promote oak natural regeneration. The composition of the formed young stands is optimal and meets the objectives of forest management in the study region.

Soil bacterial communities play a remarkable role in nutrient cycling, significantly affecting soil organic material content, soil fertility, and, in an indirect way, plant succession processes. Conversely, vegetation type influences microbial soil life. The present study compared the bacterial microbiome composition, diversity and catabolic activity profile of topsoil samples collected under three different forest types (a twice-coppiced black locust stand, a young, naturally reforested, and a middle-aged mixed pedunculate oak stand) planted on former arable land in the early 20th century. Diversity indices determined during 16S ribosomal RNA sequencing-based metagenome analysis indicated that the black locust stand had the highest soil bacterial community diversity. At the phylum level, Acidobacteriota, Actinobacteriota, Proteobacteria, Verrucomicrobiota, Bacteroidota, and Gemmatimonadota were the most abundant taxa in the forest soils. Concerning soil parameters, redundancy analysis revealed that pH had the highest impact on bacterial community structure and pH, and soil organic carbon content on the samples' respiration patterns. As for catabolic activity, the recently clearcut oak forest showed the lowest substrate-induced respiration, and citrate was the main driver for the inter-stand variability of microbial activity. Our results confirm that soil parameters and forest type influence the composition and functioning of the soil bacterial microbiome. [ABSTRACT FROM AUTHOR]

Abstract Key message We applied the generalized algebraic difference approach (GADA) to develop dynamic models of height growth for pedunculate oak (Quercus robur L.) in Serbia. According to the dominant heights, the studied region comprises some of Europe’s most productive sites for pedunculate oak. Therein, we have generated a map showing the current site index class of stands. Such a map could be used to enhance forest management and evaluate climate change impacts. Context Although sustainable forest management requires reliable prediction of forest site productivity, such indicators are currently unavailable for pedunculate oak sites in Serbia. The site index (SI) curves represent the most commonly used indirect scale for site productivity classification. The dynamic equations derived by the Generalized Algebraic Difference Approach (GADA) are the state-of-the-art approach in growth modeling, but they have not been widely applied for studying the height dynamics of pedunculate oak. Aims The main objectives of this study were to develop the first dynamic site index curves for pedunculate oak in Serbia and subsequently to provide stand-level maps with predicted site indices. Methods We have tested five flexible polymorphic equations with variable asymptotes derived by the GADA approach. Models were calibrated using artificially established growth trajectories obtained from 3636 detailed temporary sample plots. The selection of the most suitable model was accomplished according to (1) quantitative measures of goodness of fit, (2) the analysis of residual scattering, and (3) the biological plausibility of obtained height growth curves. Results After correcting the error terms with a continuous first-order autoregressive structure and conducting a three-stage performance analysis, the GADA dynamic site index model derived from the Hossfeld base equation shows the best overall properties. Insight into the oscillations of relative error suggested that 100 years is the most suitable age for site index referencing. Comparison with existing height growth models revealed greater flexibility and a considerably better representation of the height growth dynamic of pedunculate oak in the studied region. Additionally, we have produced a spatially explicit map showing the expected SI100 for 1907 stands with pedunculate oak within 22 management units. Conclusion Dynamic SI-curves based on GADA will serve forest practitioners to update management plans and serve as a reference point for benchmarking the impact of climate change and for developing adaptation strategies. The utilized approach allowed unbiased estimation of SI100 across all age classes so that the results could be mapped at a broader scale. This study provides the second known application of the dynamic model for pedunculate oak in Europe but the first that includes some of the most productive sites in the species distribution range.

Tree branches from forest tree harvesting for the timber industry are an important energy feedstock. Solid biofuel in the form of wood chips, produced from branches, is an excellent renewable energy source for generating heat and electricity. However, the properties of wood chips as a solid biofuel produced from forest tree branches can vary greatly depending on the species from which they have been produced. Therefore, this study aimed to assess the thermophysical properties and elemental composition of fresh branches harvested from nine tree species (pedunculate oak, silver birch, European ash, common aspen, grey alder, Norway maple, Scots pine, European larch and Norway spruce) over three consecutive years (2020–2022). The branches of the tree species most commonly found in Polish forests (Scots pine) were characterized by the highest heating value (an average of 20.74 GJ Mg−1 DM), the highest carbon content (an average of 55.03% DM), the lowest ash (an average of 0.60% DM) and nitrogen contents (an average of 0.32% DM), and low sulfur (an average of 0.017% DM) and chlorine contents (an average of 0.014% DM). A cluster analysis showed that the branches of all three coniferous tree species (Scots pine, Norway spruce and European larch) formed one common cluster, indicating similar properties. The branches of the European ash were characterized by the lowest wood moisture content (an average of 37.19% DM) and thus the highest lower heating value (an average of 10.50 GJ Mg−1). During the three years of the study, the chlorine and ash contents of the branches of the tree species under study exhibited the highest variability. [ABSTRACT FROM AUTHOR]

Key message: We applied the generalized algebraic difference approach (GADA) to develop dynamic models of height growth for pedunculate oak (Quercus robur L.) in Serbia. According to the dominant heights, the studied region comprises some of Europe's most productive sites for pedunculate oak. Therein, we have generated a map showing the current site index class of stands. Such a map could be used to enhance forest management and evaluate climate change impacts. Context: Although sustainable forest management requires reliable prediction of forest site productivity, such indicators are currently unavailable for pedunculate oak sites in Serbia. The site index (SI) curves represent the most commonly used indirect scale for site productivity classification. The dynamic equations derived by the Generalized Algebraic Difference Approach (GADA) are the state-of-the-art approach in growth modeling, but they have not been widely applied for studying the height dynamics of pedunculate oak. Aims: The main objectives of this study were to develop the first dynamic site index curves for pedunculate oak in Serbia and subsequently to provide stand-level maps with predicted site indices. Methods: We have tested five flexible polymorphic equations with variable asymptotes derived by the GADA approach. Models were calibrated using artificially established growth trajectories obtained from 3636 detailed temporary sample plots. The selection of the most suitable model was accomplished according to (1) quantitative measures of goodness of fit, (2) the analysis of residual scattering, and (3) the biological plausibility of obtained height growth curves. Results: After correcting the error terms with a continuous first-order autoregressive structure and conducting a three-stage performance analysis, the GADA dynamic site index model derived from the Hossfeld base equation shows the best overall properties. Insight into the oscillations of relative error suggested that 100 years is the most suitable age for site index referencing. Comparison with existing height growth models revealed greater flexibility and a considerably better representation of the height growth dynamic of pedunculate oak in the studied region. Additionally, we have produced a spatially explicit map showing the expected SI100 for 1907 stands with pedunculate oak within 22 management units. Conclusion: Dynamic SI-curves based on GADA will serve forest practitioners to update management plans and serve as a reference point for benchmarking the impact of climate change and for developing adaptation strategies. The utilized approach allowed unbiased estimation of SI100 across all age classes so that the results could be mapped at a broader scale. This study provides the second known application of the dynamic model for pedunculate oak in Europe but the first that includes some of the most productive sites in the species distribution range. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Acorn production in oak (Quercus spp.) shows considerable inter-annual variation, known as masting, which provides a natural defence against seed predators but a highly-variable supply of acorns for uses such as in commercial tree planting each year. Anthropogenic emissions of greenhouse gases have been very widely reported to influence plant growth and seed or fruit size and quantity via the ‘fertilisation effect’ that leads to enhanced photosynthesis. To examine if acorn production in mature woodland communities will be affected by further increase in CO2, the contents of litter traps from a Free Air Carbon Enrichment (FACE) experiment in deciduous woodland in central England were analysed for numbers of flowers and acorns of pedunculate oak (Quercus robur L.) at different stages of development and their predation levels under ambient and elevated CO2 concentrations. Inter-annual variation in acorn numbers was considerable and cyclical between 2015 and 2021, with the greatest numbers of mature acorns in 2015, 2017 and 2020 but almost none in 2018. The numbers of flowers, enlarged cups, immature acorns, empty acorn cups, and galls in the litter traps also varied amongst years; comparatively high numbers of enlarged cups were recorded in 2018, suggesting Q. robur at this site is a fruit maturation masting species (i.e., the extent of abortion of pollinated flowers during acorn development affects mature acorn numbers greatly). Raising the atmospheric CO2 concentration by 150 μL L−1, from early 2017, increased the numbers of immature acorns, and all acorn evidence (empty cups + immature acorns + mature acorns) detected in the litter traps compared to ambient controls by 2021, but did not consistently affect the numbers of flowers, enlarged cups, empty cups, or mature acorns. The number of flowers in the elevated CO2 plots’ litter traps was greater in 2018 than 2017, one year after CO2 enrichment began, whereas numbers declined in ambient plots. Enrichment with CO2 also increased the number of oak knopper galls (Andricus quercuscalicis Burgsdorf). We conclude that elevated CO2 increased the occurrence of acorns developing from flowers, but the putative benefit to mature acorn numbers may have been hidden by excessive pre- and/or post-dispersal predation. There was no evidence that elevated CO2 altered masting behaviour. [ABSTRACT FROM AUTHOR]

The emission of CO2 from soil represents one of the most significant fluxes between terrestrial ecosystems and the atmosphere. It is crucial to investigate the impact of stand age on soil CO2 emissions in order to evaluate the possibility of carbon sequestration through the establishment of new forests. In this study, soil CO2 emissions and microclimate variables (soil temperature and moisture) were investigated in the chronosequence of three differently aged stands (4-, 14-, and 70-year-old stands) in floodplain pedunculate oak (Quercus robur L.) forests in Serbia. This study highlights how the artificial regeneration of pedunculate oak forests (establishment of new stands) can affect CO2 emissions from soils. Seasonal fluctuations in soil CO2 emissions were observed in all of the monitored stands, along with variations in the influence of soil temperature and moisture. Multiple linear regression, incorporating soil temperature, soil moisture, and their interaction, offered the most comprehensive explanation for the variation observed in soil CO2 emissions. The seasons had statistically significant effects (p < 0.001) on CO2 emission from the soil in the examined stands during 2022. The youngest stand (4-year-old) had significantly higher soil CO2 emissions (p < 0.05) compared to the older stands over the entire study period (2021–2022). These results showed that the 70-year-old stand (natural high stand) had significantly lower soil CO2 emissions compared to the 4-year-old stand (artificially regenerated stand).

The research analyzed the growth of natural regeneration installed by group shelterwood in a mixed species riparian stand looking at: the influence of the position in the regeneration gaps (fertile edge of the gap; differences between the center and edge of gap) and the influence of the type of cleaning-respacing works on the growth of regeneration. Cleaning respacing was applied in three different ways: cutting from ground level the competing vegetation and breaking the stems of unwanted trees at 1/3 and 1/2 of the height of the oak trees chosen to be kept, respectively. For comparison, some control (no tending) areas were also set in the field. The results show that the fertile edge is in the south-west (size and biomass were significantly higher at this edge than in the north-east edge) indicating that summer heat is the limiting factor rather than shade . All measured variables (height, diameter, and total aboveground biomass) had significantly higher values in the center of the gap than at the edge. Thus, despite the thinning of the stand between gaps, competition with mature stands still plays an important role. The three methods of cleaning-respacing did not produce significant differences in the central area, although there appears to be a tendency for bottom cutting to result in trees with higher biomass than the other two cases. At the edge, where competition with the old stand dominates, the situation is similar. However, a negative effect on oak regeneration survival is observed (average number of saplings per sample area at the edge is only 8.7, compared to 14.2 and 13.1 saplings in the middle and central areas). So timely and consistent application of tending operations remains important. As the saplings, even at the gap edge, have reached (only seven years since regeneration process started) sizes well above those recommended (in the technical guidelines) as a threshold for applying the final felling, the regeneration period may be shorter than that provided for in the management plan. [ABSTRACT FROM AUTHOR]

Agroforestry systems are gaining increasing attention worldwide due to their several benefits both for landowners and also for the environment. Even though Romania has a great potential for adopting these systems on a large scale, only a few examples exist. The aim of this research was to highlight the main agroforestry systems that could be introduced in plain regions across Bihor County, Western Romania. A selection of the most suitable woody species and cereals was carried, based on available data and information. In order to select the most suitable combination, a set of eight criteria was considered and an Analytical Hierarchy Process Analysis was performed, with the aid of the Expert Choice Desktop (v. 11.5.1683) software package. The combinations that had the black locust as the main tree species scored better in comparison with the ones that had pedunculate oak as a main species. This research should be regarded as a first and important step in the analysis of several combinations of agroforestry systems that could be implemented across plain regions of Bihor County. Lastly, this proposed model could be replicated in similar studies aimed at selecting the most suitable agroforestry systems for certain sites. Future research should also consider criteria that account for various aspects, including the functional relationships of these future green spaces with nearby areas. [ABSTRACT FROM AUTHOR]

Clear-cutting is the most robust intervention in a forest ecosystem, causing marked changes in ecosystem processes. Although the effects of forest harvesting have been widely investigated, comparative studies can provide vital supplementary information concerning specific fields, including changes in soil microbiota structure and functioning. Our study examined the soil bacterial community composition, diversity, and activity of a mixed pedunculate oak stand over three years after clear-cutting based on 16S rRNA sequencing and substrate-induced respiration data. In addition, we conducted a yearly comparison with a control oak stand already in the regeneration phase. According to our results, the forest harvest caused only limited changes in the diversity, structure, and activity of the soil bacterial community of the oak stand, suggesting that soil parameters influence the soil bacterial community structure and functioning more significantly than the cessation of forest cover.

Soil bacterial communities play a remarkable role in nutrient cycling, significantly affecting soil organic material content, soil fertility, and, in an indirect way, plant succession processes. Conversely, vegetation type influences microbial soil life. The present study compared the bacterial microbiome composition, diversity and catabolic activity profile of topsoil samples collected under three different forest types (a twice-coppiced black locust stand, a young, naturally reforested, and a middle-aged mixed pedunculate oak stand) planted on former arable land in the early 20th century. Diversity indices determined during 16S ribosomal RNA sequencing-based metagenome analysis indicated that the black locust stand had the highest soil bacterial community diversity. At the phylum level, Acidobacteriota, Actinobacteriota, Proteobacteria, Verrucomicrobiota, Bacteroidota, and Gemmatimonadota were the most abundant taxa in the forest soils. Concerning soil parameters, redundancy analysis revealed that pH had the highest impact on bacterial community structure and pH, and soil organic carbon content on the samples’ respiration patterns. As for catabolic activity, the recently clearcut oak forest showed the lowest substrate-induced respiration, and citrate was the main driver for the inter-stand variability of microbial activity. Our results confirm that soil parameters and forest type influence the composition and functioning of the soil bacterial microbiome.

A total of 65 pedunculate oak (Quercus robur L.) provenances from the southern, central, northern, and eastern parts of the oak distribution range in Vinnytsia region (Central Ukraine) were assessed in a common garden experiment. Analysis of the population's survival dynamics indicates an increase with age in the adaptive capacity of the provenances to the environmental conditions. In the initial stage, up to 10 years, the survival rate of the local populations was about 75%, by 40 years the survival decreased to 15%. At the same time, the number of trees of other provenances, which were characterised by higher survival rate, increased. The best adaptive capacity was obtained for the Rivne (Ostrozke), Kirovohrad (Svitlovodske), Chuvash (Kanaske), and Ulyanovsk (Melekske) provenances. The indicators of average height of the trees and geographic longitude (r=-0.513) and latitude of the natural growth of the populations (r=-0.474) are characterised by a significant and moderately close relationship. Oak populations differ by average diameter and remoteness from the natural location ratio (r=-0.431), and by the geographic latitude of their growing place (r=-0.478) in a moderate correlation. According to the comprehensive assessment of the non-local populations, which included survival rate, mean diameter and height, and tree breeding category, we can conclude that in general, the central populations have optimal values. Populations of Bryansk, Khmelnytskyi, Zaporizhzhya, and Cherkassy origin, as well as the local ones, have the highest values. The lowest indicators were observed manly for the northern oak populations. [ABSTRACT FROM AUTHOR]

The two main species, sessile oak (Quercus petraea Liebl.) and pedunculate oak (Quercus robur L.), predominant in French forests, are mainly used for aging wines and spirits; however, the potential of oak wood extract as a source of natural antioxidants, due to its high polyphenol content, could be more widely exploited. This study focuses on three oak species, the two that are well-known, namely, sessile and pedunculate oak, and a third that has seldom been described and valorized, namely, pubescent oak (Quercus pubescens). Water extracts of these three species were fractionated by semi-preparative HPLC. The antioxidant activities of crude extracts and fractions were measured by colorimetric and enzymatic tests. The anti-elastase and anti-collagenase activities of the extracts and their fractions were also evaluated. In parallel, samples were analyzed by UHPLC-HRMS to correlate the activity with the molecular composition using molecular networks. The results obtained for the total extract of the three species were compared to determine if the activity depended on the species. The results within the same species were also compared to highlight which fraction and, therefore, which molecular family was involved in the activity of the total extract. The various antioxidant tests showed good activity of the total extract for the three species of oak and a very good anti-collagenase activity. The antioxidant activity of oak extract has already been proven in the literature and this is correlated with its richness in polyphenols. This study shows that each molecular family of the extract contributes to the activities of the total extract. Oak extract can be used to neutralize the ROS produced during oxidative stress and to prevent the degradation of collagen and elastase during skin aging. Its complementary properties make oak extract a valuable ingredient to act against skin aging. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species (Quercus spp.) displaying recalcitrance in seed and vegetative propagation methods. Our study aimed to assess the regenerative potential of Quercus robur trees of different ages (up to 800 years) during micropropagation. We also aimed to determine how in vitro conditions can influence in vitro regeneration responses. Lignified branches collected from 67 selected trees were cultivated ex vitro in culture pots at 25 °C to obtain epicormic shoots (explant sources). The explants were cultivated on an agar medium supplemented with 0.8 mg L−1 6-benzylaminopurine (BAP) for at least 21 months. In a second experiment, two different shoot multiplication conditions (temporary immersion—RITA® bioreactor and agar medium) and two culture medium formulations (Woody Plant Medium and modified Quoirin and Lepoivre medium) were tested. The results showed that the mean length of the epicormic shoots obtained in a pot culture was a function of donor age and was similar among the group of younger trees (ca. 20–200 years), and varied between older trees (ca. 300–800 years). The efficiency of in vitro shoot multiplication strictly depended on the genotype. A sustainable in vitro culture (defined as survival after 6 months) was only possible for half of the tested old donor trees, even when they survived the first month of in vitro growth. A continuous monthly increase in the number of in vitro cultured shoots was reported in younger oaks and in some old oaks. We found a significant effect of the culture system and the macro- and micronutrient composition on in vitro shoot growth. This is the first report demonstrating that the in vitro culture can be successfully applied to the propagation of even 800-year-old pedunculate oak trees. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The drought sensitivity of the pedunculate oak (Quercus robur L.) poses a threat to its survival in light of climate change. Mycorrhizal fungi, which orchestrate biogeochemical cycles and particularly have an impact on the plant's defense mechanisms and metabolism of carbon, nitrogen, and phosphorus, are among the microbes that play a significant role in the mitigation of the effects of climate change on trees. The study's main objectives were to determine whether ectomycorrhizal (ECM) fungi alleviate the effects of drought stress in pedunculate oak and to investigate their priming properties. The effects of two levels of drought (mild and severe, corresponding to 60% and 30% of field capacity, respectively) on the biochemical response of pedunculate oak were examined in the presence and absence of ectomycorrhizal fungi. To examine whether the ectomycorrhizal fungi modulate the drought tolerance of pedunculate oak, levels of plant hormones and polyamines were quantified using UPLC-TQS and HPLC-FD techniques in addition to gas exchange measurements and the main osmolyte amounts (glycine betaine-GB and proline-PRO) which were determined spectrophotometrically. Droughts increased the accumulation of osmolytes, such as proline and glycine betaine, as well as higher polyamines (spermidine and spermine) levels and decreased putrescine levels in both, mycorrhized and non-mycorrhized oak seedlings. In addition to amplifying the response of oak to severe drought in terms of inducible proline and abscisic acid (ABA) levels, inoculation with ECM fungi significantly increased the constitutive levels of glycine betaine, spermine, and spermidine regardless of drought stress. This study found that compared to non-mycorrhized oak seedlings, unstressed ECM-inoculated oak seedlings had higher levels of salicylic (SA) and abscisic acid (ABA) but not jasmonic acid (JA), indicating a priming mechanism of ECM is conveyed via these plant hormones. According to a PCA analysis, the effect of drought was linked to the variability of parameters along the PC1 axe, such as osmolytes PRO, GB, polyamines, and plant hormones such as JA, JA-Ile, SAG, and SGE, whereas mycorrhization was more closely associated with the parameters gathered around the PC2 axe (SA, ODPA, ABA, and E). These findings highlight the beneficial function of the ectomycorrhizal fungi, in particular Scleroderma citrinum, in reducing the effects of drought stress in pedunculate oak. [ABSTRACT FROM AUTHOR]

Oak bark is a rich niche for beneficial bioactive compounds. It is known that the amount of the compounds found in plant tissues can depend on species, genotype, growth site, etc., but it is unclear whether oak phenology, i.e., late or early bud burst, can also influence the amount of phenols and antioxidants that can be extracted. We tested two Quercus robur populations expressing different phenology and five half-sib families in each population to see how phenology, genotype, as well as extrahent differences (75% methanol or water) can determine the total phenol, total flavonoid content, as well as antioxidant activity. Significant statistical differences were found between half-sib families of the same population, between populations representing different oak phenology and different extrahents used. We determined that the extraction of flavonoids was more favorable when using water. So was antioxidant activity using one of the indicators, when significant differences between extrahents were observed. Furthermore, in families where there was a significant difference, phenols showed better results when using methanol. Overall, late bud burst families exhibited higher levels in all parameters tested. Thus, we recommend that for further bioactive compound extraction, all these factors be noted. [ABSTRACT FROM AUTHOR]

Oak powdery mildew caused by Erysiphe alphitoides (Griffon and Maubl.; U. Braun & S. Takam.) is a common disease in European forests. One of the most susceptible species is the pedunculate oak (Quercus robur L.). Presently, a few methods are available to control powdery mildew, e.g., the use of fungicides (e.g., based on citric acid), antagonistic fungi or bacteria, chemical treatments (e.g., sulphur, potassium bicarbonate) or genetic resistance. In our study, we aimed to check the effects of using chitosan derivatives and novel active substances inducing the plants' natural resistance: benzodiathiadiazole (both in neutral and salt form). 84 pedunculate oak seedlings were subjected to the experiment in three treatment variants (plus positive and negative controls). The plants were treated with active substances and inoculated with E. alphitoides. Although the powdery mildew symptoms appeared in all variants, they were manifested mainly by the mycelium in the form of small spots. The experiment indicated that the highest limitation of powdery mildew mycelium was achieved by applying N-methyl-N-methoxyamide-7-carboxybenzo(1,2,3)thiadiazole (BTHWA). The application of BTHWA reduced disease development by 88.9% when compared to the effects of the other variants. [ABSTRACT FROM AUTHOR]

Subfossil wood is a valuable and rare material often used for production of expensive furniture and decorative artistic items of unique beauty. Its mechanical and tribological properties are still being studied and are considered specific due to the particular conditions of its long-lasting formation in aqueous sediment sludge. Various elements that have been impregnated into the wood tissue over many years make the machining and grinding of this type of wood rather difficult compared to normal recent wood. The main objective of this study was to determine the influence of the abrasive grain size of sandpaper on the abrasion volume loss of recent and two subfossil oak samples in three characteristic sections (cross, radial, and tangential). The results showed that the average size of abrasive grains and the orientation of the wood structure have an influence on the abrasion volume loss of all three samples. The phenomenon of the critical size of abrasive grains was observed in all samples and on all sections. As the size of abrasive grains increased to the critical size, the abrasive volume loss of the sample increased simultaneously. The lowest abrasion volume loss was observed on recent oak. In all samples, the lowest volume loss was measured on the cross sections, and the tangential and radial sections had mutually equal values. It was also found that the increase in the size of abrasive grains to a critical value resulted in the increasing value of the absolute difference between the abrasion volume loss of the cross, radial, and tangential section samples, while the relative relations between the abrasive volume loss values of three different sections (C/R, C/T, R/T) within the same grit of sandpaper remained quite similar. [ABSTRACT FROM AUTHOR]

The vitality of European forests continues to decline due to new pests and diseases, climate-change related disturbances and high loads of atmospheric nitrogen deposition. Deteriorating soil health is a major factor underpinning the low vitality of West-European forests. Selecting tree species with soil ameliorative traits is proposed as an avenue to counteract soil acidification and improve overall forest vitality. Here we evaluate the impact of black cherry (Prunus serotina Ehrh.), a known rich litter species, on the vitality of neighboring pedunculate oak (Quercus robur L.) in ten mixed forests on sand in Germany, Belgium and the Netherlands. We found that black cherry admixture increases foliar N and P to a surplus whereas it causes deficiencies in foliar Mg, thereby resulting in an overall negative effect on oak foliar nutrient concentrations. Contrary, defoliation of oak leaves by herbivory decreases with the proximity of black cherry. Using structural equation modelling (SEM), we tested the hypothesized 'improved soil health' pathway. Our analyses showed that black cherry admixture leads to lower accumulation in the humus layer, resulting in higher soil base saturation which has a positive effect on foliar Ca yet a negative effect on total chlorophyll. Moreover, the SEM illustrated that herbivory of oak leaves decreases when black cherry is admixed, both via dilution and improved soil health. Indirect effects of black cherry on oak vitality via "improved soil health" in our SEM are however small in comparison to direct relations. Hence, our study showed that the combined positive and negative impacts of black cherry on oak vitality are limited, which tempers the potential benefits of using the rich litter species to counteract oak decline via improved soil health - yet, the concern of black cherry as an invasive alien species negatively affecting the vitality of mature pedunculate oak trees may also be exaggerated. [ABSTRACT FROM AUTHOR]

Plants interact with a large diversity of microbes and insects, both below and above ground. While studies have shown that belowground microbes affect the performance of plants and aboveground organisms, we lack insights into how belowground microbial communities may shape interactions between aboveground pathogens and insects. We investigated how soil microbiomes and aboveground organisms affect plant growth and development, and whether differences in soil microbiomes influence interactions between aboveground organisms. We conducted a growth‐chamber experiment with oak seedlings Quercus robur growing in three soils with similar abiotic soil properties but with distinct natural soil microbiomes. Seedlings were subjected to single or dual attack by powdery mildew Erysiphe alphitoides and aphids Tuberculatus annulatus, either in the presence or absence of prior attack by a free‐feeding caterpillar Phalera bucephala. Soil microbiomes were associated with differences in seedling height, and seedlings with multiple aboveground organisms had more but smaller leaves than healthy seedlings. The soil microbiome affected the severity of powdery mildew infection, and mediated the impact of co‐occurring aboveground organisms on aphid population size. Our study highlights that plant performance is affected by natural soil microbiomes as well as aboveground organisms, and that natural soil microbiomes can affect interactions between pathogens and insects. These findings are important to understand species interactions in natural systems, as well as for practical applications, such as manipulation of soil microbiomes to manage agricultural pests and diseases. [ABSTRACT FROM AUTHOR]

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 differential were 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. For 2012, 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. [ABSTRACT FROM AUTHOR]

Norway maple (Acer platanoides L.) is a key species of broadleaved forests whose population genetics is poorly studied using modern genetic tools. We used ISSR analysis to explore genetic diversity and differentiation among 10 Russian populations on the eastern margin of the species range of distribution, and to compare the revealed patterns with the results of our population genetic studies of pedunculate oak (Quercus robur L.). In the first set comparatively high heterozygosity and allelic diversity were found (expected heterozygosity HE = 0.160 ± 0.033, number of alleles na = 1.440 ± 0.080, effective number of alleles ne = 1.271 ± 0.062) in comparison with strongly fragmented and geographically isolated small maple stands of the second set (HE = 0.083 ± 0.011, na = 1.281 ± 0.031, ne = 1.136 ± 0.019). A relatively high genetic differentiation among populations was detected (the proportion of the inter-population component of total genetic variation, GST = 0.558 ± 0.038). In the Cis-Urals, local groups of populations that are confined to the northern, middle and southern parts of the Urals were identified. On the contrary, the current significant fragmentation of the pedunculate oak distribution area in the same study area did not lead to any noticeable genetic differentiation among the majority of populations, the values of the population genetic diversity were very similar in different parts of the Southern Urals.

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 differential were 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. For 2012, 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.

Lowland forests benefiting from groundwater availability are important ecosystems in Central Europe, both from ecological and economic perspectives. Besides a great reduction in their extent in the historical times and further shifts in the land use and water management regimes intensified during the industrial era, continuing changes in the groundwater and overall hydro-climatic conditions can pose significant challenges to them. Although tree-ring analyses serve as widely used tools to assess the climatic impact on tree growth and vitality, few studies have attempted to investigate the effects of subsurface hydrology on interannual fluctuations in xylem production. In this study, we compared the tree-ring width series of pedunculate oak (Quercus robur L.) from a forested area in southwestern Hungary with the time series of monthly groundwater depth and climatic variables over the period of 1920–2017 with a specific focus on 1961–2017. The radial growth of the studied trees showed the strongest relationship with late winter and early spring groundwater and drought conditions preceding the growing season, differing from the commonly reported climatic signals marked by early summer meteorological conditions of the vegetation season. The results suggest that the groundwater recharge during the dormant period preceding the vegetation season and the groundwater levels in early spring were among the key limiting factors on tree growth in the study area. In the growing years starting with a sufficiently high groundwater table, even scarce summer precipitation did not seem to limit radial growth drastically. However, unfavorable shifts in climatic conditions during the past few decades and the associated uncertainties in the future groundwater regime imply that additional active measures aimed at maintaining and restoring groundwater conditions may well be highly beneficial for sustaining groundwater-dependent forest ecosystems and their productivity. [ABSTRACT FROM AUTHOR]

Opencast mining is currently one of the most destructive economic activities of natural ecosystems. Many restoration techniques have been developed to promote the recovery of terrestrial ecosystems degraded by mining, and afforestation and reforestation are among the most important methods to this purpose. In this study, we evaluated the combined effect of tree species mixture and thinning intervention on growth dynamics and responses to the climate of a target native planted oak (pedunculate oak, Quercus robur L.) about 40 years after reforestation of an opencast lignite mining area in Central Italy. The species used for reforestation were a native tree species (Q. robur L.), two valuable broadleaved trees (Fraxinus angustifolia Vahl. and Prunus avium L.) and a nitrogen-fixing tree (Alnus cordata Loisel.) to improve timber quality and restore the ecological and environmental value of the degraded land. Climate-growth relationships for precipitation, the Standardised Precipitation-Evaporation Index (SPEI), and temperature (on a monthly and seasonal scale) were tested together with indices based on tree-ring responses to drought. Thinning improved the stem quality and promoted a significant long-term increase in basal area increment (BAI, +31.0%) only in the mixture with alder. The thinning effect slightly mitigated radial growth reductions of oak trees during drought (resistance) and produced a general improvement in the magnitude of resilience and post-drought growth recovery (+37% and +27% on average, respectively). This effect was most evident when oak trees were mixed with only the N-fixing alder species, both after shorter- and longer-term drought or rainfall reduction. In conclusion, the mixture with alder combined with thinning practices resulted in the best management option to produce good-quality stems, improve growth performances, and mitigate drought effects in the recovery of opencast lignite mines through reforestation. [ABSTRACT FROM AUTHOR]

A shift in management to improve the ecological function of mature plantations of exotic species can have important effects on the ecosystem climate mitigation potential. This study investigated the effect of two common forest management strategies for Scots pine (Pinus sylvestris L.) stands on the C storage after 15 years of management. Two pairs of forest stands on poor sandy soil and under the maritime influence in Brasschaat, Belgium, were observed as case studies. The observed forest management strategies were (i) thinning and group planting of oak saplings (Quercus robur L.) and (ii) clear cut, followed by replanting of young oak. For each stand, all forest C pools (aboveground biomass, belowground biomass, litter, and mineral soil) were determined. Results showed, surprisingly, no significant difference in the whole ecosystem C stock for both forest management strategies after 15 years of management. However, after the clear cut and the new plantation, the C in the top 30 cm layer of the mineral soil increased, while it decreased on the forest floor. For thinning with group planting, the C stocks reduced within the 10–30 cm soil layer without impact on the total soil C. Therefore, the shift in management did result in a different allocation of the belowground C, particularly after a clear cut. The results are not only relevant for the study region but also for managed Scots pine forests in neighboring regions of the Atlantic zone of Western Europe. [ABSTRACT FROM AUTHOR]

In light of climate change, pedunculate oak (Q. robur L.) was marked as the most threatened European tree species. Pedunculate oak is particularly jeopardized by powdery mildew disease caused by Erysiphe alphitoides. We hypothesized that priming of this tree species with ectomycorrhizal fungi could mitigate biotic stress and produce bioprotective properties against the disease. In this study, we have compared oaks' foliar physiological and biochemical responses upon infection with E. alphitoides in the presence and absence of ectomycorrhizal fungi (ECM). The main aim of this study was to inspect how ECM modulate an oak's biochemical response to infection with E. alphitoides, particularly at the level of the accumulation of the main polyamines (putrescine, spermidine, and spermine), soluble osmolytes (proline and glycine betaine), and phenolics (total phenolic content, flavonoids, and condensed tannins). A polyamine quantification was performed after derivatization by using high-performance liquid chromatography (HLPC) coupled with fluorescent detection. Oak seedlings inoculated with ECM fungi exhibited significantly higher levels of putrescine, spermine, and proline compared to non-inoculated seedlings, indicating the priming properties of the ECM. E. alphitoides caused an increase in individual and total polyamine content and lipid peroxidation in oak leaves regardless of the effect of ECM, while causing a decrease in physiological and antioxidative parameters and water use efficiency (WUE). Common biochemical parameters may contribute to understanding the underpinning plant defense mechanisms in three-way interactions among plants and pathogenic and ectomycorrhizal fungi and can be used as reliable adaptability descriptors in the context of climate change. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Plants interact with a multitude of microorganisms and insects, both belowand above ground, which might influence plant metabolism. Despite this, we lack knowledge of the impact of natural soil communities and multiple aboveground attackers on the metabolic responses of plants, and whether plant metabolic responses to single attack can predict responses to dual attack. We used untargeted metabolic fingerprinting (gas chromatographymass spectrometry, GC-MS) on leaves of the pedunculate oak, Quercus robur, to assess the metabolic response to different soil microbiomes and aboveground single and dual attack by oak powdery mildew (Erysiphe alphitoides) and the common oak aphid (Tuberculatus annulatus). Distinct soil microbiomes were not associated with differences in the metabolic profile of oak seedling leaves. Single attacks by aphids or mildew had pronounced but different effects on the oak leaf metabolome, but we detected no difference between the metabolomes of healthy seedlings and seedlings attacked by both aphids and powdery mildew. Our findings show that aboveground attackers can have species-specific and non-additive effects on the leaf metabolome of oak. The lack of a metabolic signature detected by GC-MS upon dual attack might suggest the existence of a potential negative feedback, and highlights the importance of considering the impacts of multiple attackers to gain mechanistic insights into the ecology and evolution of species interactions and the structure of plant-associated communities, as well as for the development of sustainable strategies to control agricultural pests and diseases and plant breeding. [ABSTRACT FROM AUTHOR]

The seasonal dynamics of leaf damage caused by phyllophagous insects to the pedunculate oak Quercus robur in the northeast of its distribution area was studied. The research was carried out in 2013–2016 near the Udmurt University's Biological Station (56°82′N, 53°90′E) in a floodplain oak forest of the Siva River, Votkinskii District, Udmurt Republic. The complex of oak phyllophages included 71 insect species from 23 families and 4 orders: Lepidoptera (59.2%), Coleoptera (25.3%), Hymenoptera (12.7%), and Diptera (2.8%). The species diversity of three orders (Coleoptera, Hymenoptera, and Diptera) was the highest in spring and early summer. The number of Lepidoptera species ranged from 21 to 25 between June 10 and August 30. The degree of trophic specialization of the oak phyllophages was closely related to their ecological characteristics. Most mining species (71.4%) and all the gall-forming ones were monophagous. By contrast, polyphagous species predominated among the chewing, skeletonizing, and leaf-rolling phyllophages: 92.4, 85.7, and 75%, respectively. The main damage to oak leaves was inflicted by phyllophages in spring: 77.1 ± 2.2%, then it decreased to 12.2 ± 1.6, 3.3 ± 1.0, and 7.4 ± 2.1% in early summer, summer, and autumn, respectively (n = 8 in all the cases). [ABSTRACT FROM AUTHOR]

Plants interact with a multitude of microorganisms and insects, both below- and above ground, which might influence plant metabolism. Despite this, we lack knowledge of the impact of natural soil communities and multiple aboveground attackers on the metabolic responses of plants, and whether plant metabolic responses to single attack can predict responses to dual attack. We used untargeted metabolic fingerprinting (gas chromatography-mass spectrometry, GC-MS) on leaves of the pedunculate oak, Quercus robur, to assess the metabolic response to different soil microbiomes and aboveground single and dual attack by oak powdery mildew (Erysiphe alphitoides) and the common oak aphid (Tuberculatus annulatus). Distinct soil microbiomes were not associated with differences in the metabolic profile of oak seedling leaves. Single attacks by aphids or mildew had pronounced but different effects on the oak leaf metabolome, but we detected no difference between the metabolomes of healthy seedlings and seedlings attacked by both aphids and powdery mildew. Our findings show that aboveground attackers can have species-specific and non-additive effects on the leaf metabolome of oak. The lack of a metabolic signature detected by GC-MS upon dual attack might suggest the existence of a potential negative feedback, and highlights the importance of considering the impacts of multiple attackers to gain mechanistic insights into the ecology and evolution of species interactions and the structure of plant-associated communities, as well as for the development of sustainable strategies to control agricultural pests and diseases and plant breeding.

The conservation of the genetic resources of old trees is crucial to their ecological role but is extremely difficult, especially for oak species (Quercus spp.) displaying recalcitrance in seed and vegetative propagation methods. Our study aimed to assess the regenerative potential of Quercus robur trees of different ages (up to 800 years) during micropropagation. We also aimed to determine how in vitro conditions can influence in vitro regeneration responses. Lignified branches collected from 67 selected trees were cultivated ex vitro in culture pots at 25 °C to obtain epicormic shoots (explant sources). The explants were cultivated on an agar medium supplemented with 0.8 mg L−1 6-benzylaminopurine (BAP) for at least 21 months. In a second experiment, two different shoot multiplication conditions (temporary immersion—RITA® bioreactor and agar medium) and two culture medium formulations (Woody Plant Medium and modified Quoirin and Lepoivre medium) were tested. The results showed that the mean length of the epicormic shoots obtained in a pot culture was a function of donor age and was similar among the group of younger trees (ca. 20–200 years), and varied between older trees (ca. 300–800 years). The efficiency of in vitro shoot multiplication strictly depended on the genotype. A sustainable in vitro culture (defined as survival after 6 months) was only possible for half of the tested old donor trees, even when they survived the first month of in vitro growth. A continuous monthly increase in the number of in vitro cultured shoots was reported in younger oaks and in some old oaks. We found a significant effect of the culture system and the macro- and micronutrient composition on in vitro shoot growth. This is the first report demonstrating that the in vitro culture can be successfully applied to the propagation of even 800-year-old pedunculate oak trees.

Dieback of young Quercus robur seedlings can limit natural regeneration in mixed‐species forest stands in Poland. The aim of this study was to examine the role of fungi in the dieback of oak seedlings in central Europe. Fungi were isolated from the stems and roots of Q. robur, from both healthy seedlings and seedlings with symptoms, that were sampled from four stands in Poland. In total, 111 distinct taxa were identified. Ascomycota was dominant, representing 95.6% of the isolates. Among the taxa identified, Alternaria alternata, Colletotrichum fioriniae, Colletotrichumgodetiae, Coniella quercicola, Diaporthe eres, Gnomoniopsis paraclavulata, Ilyonectria rufa, Mucor genevensis, Penicillium glandicola, Tubakia dryina, and Umbelopsis changbaiensis were most frequently isolated, and were consistently found in stems and roots of both healthy and diseased plants. The community compositions of fungi in healthy and diseased stems were similar, although Fusarium species, especially Fusarium sp. 1 (FTSC 5) and F. sporotrichioides, were found mainly in seedlings with symptoms. The pathogenicity of the most consistently isolated species from stems and roots of diseased seedlings was tested on Q. robur seedlings. F. sporotrichioides caused the largest lesions on inoculated seedlings. Six weeks after inoculation, D. eres, C. fioriniae, G. paraclavulata, T. dryina, and F. sporotrichioides killed 0%–18.8% of seedlings, while I. rufa and Ilyonectriapseudodestructans did not cause any lesions or other symptoms. This study is the first comprehensive report suggesting that massive fungal attack can lead to oak seedling dieback in mixed‐species forest stands in central Europe. [ABSTRACT FROM AUTHOR]

The drought sensitivity of the pedunculate oak (Quercus robur L.) poses a threat to its survival in light of climate change. Mycorrhizal fungi, which orchestrate biogeochemical cycles and particularly have an impact on the plant’s defense mechanisms and metabolism of carbon, nitrogen, and phosphorus, are among the microbes that play a significant role in the mitigation of the effects of climate change on trees. The study’s main objectives were to determine whether ectomycorrhizal (ECM) fungi alleviate the effects of drought stress in pedunculate oak and to investigate their priming properties. The effects of two levels of drought (mild and severe, corresponding to 60% and 30% of field capacity, respectively) on the biochemical response of pedunculate oak were examined in the presence and absence of ectomycorrhizal fungi. To examine whether the ectomycorrhizal fungi modulate the drought tolerance of pedunculate oak, levels of plant hormones and polyamines were quantified using UPLC-TQS and HPLC-FD techniques in addition to gas exchange measurements and the main osmolyte amounts (glycine betaine-GB and proline-PRO) which were determined spectrophotometrically. Droughts increased the accumulation of osmolytes, such as proline and glycine betaine, as well as higher polyamines (spermidine and spermine) levels and decreased putrescine levels in both, mycorrhized and non-mycorrhized oak seedlings. In addition to amplifying the response of oak to severe drought in terms of inducible proline and abscisic acid (ABA) levels, inoculation with ECM fungi significantly increased the constitutive levels of glycine betaine, spermine, and spermidine regardless of drought stress. This study found that compared to non-mycorrhized oak seedlings, unstressed ECM-inoculated oak seedlings had higher levels of salicylic (SA) and abscisic acid (ABA) but not jasmonic acid (JA), indicating a priming mechanism of ECM is conveyed via these plant hormones. According to a PCA analysis, the effect of drought was linked to the variability of parameters along the PC1 axe, such as osmolytes PRO, GB, polyamines, and plant hormones such as JA, JA-Ile, SAG, and SGE, whereas mycorrhization was more closely associated with the parameters gathered around the PC2 axe (SA, ODPA, ABA, and E). These findings highlight the beneficial function of the ectomycorrhizal fungi, in particular Scleroderma citrinum, in reducing the effects of drought stress in pedunculate oak.

Oak powdery mildew caused by Erysiphe alphitoides (Griffon and Maubl.; U. Braun & S. Takam.) is a common disease in European forests. One of the most susceptible species is the pedunculate oak (Quercus robur L.). Presently, a few methods are available to control powdery mildew, e.g., the use of fungicides (e.g., based on citric acid), antagonistic fungi or bacteria, chemical treatments (e.g., sulphur, potassium bicarbonate) or genetic resistance. In our study, we aimed to check the effects of using chitosan derivatives and novel active substances inducing the plants’ natural resistance: benzodiathiadiazole (both in neutral and salt form). 84 pedunculate oak seedlings were subjected to the experiment in three treatment variants (plus positive and negative controls). The plants were treated with active substances and inoculated with E. alphitoides. Although the powdery mildew symptoms appeared in all variants, they were manifested mainly by the mycelium in the form of small spots. The experiment indicated that the highest limitation of powdery mildew mycelium was achieved by applying N-methyl-N-methoxyamide-7-carboxybenzo(1,2,3)thiadiazole (BTHWA). The application of BTHWA reduced disease development by 88.9% when compared to the effects of the other variants.

Copyright of Agronomy Science is the property of University of Life Sciences in Lublin and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Forestry Society of Croatia / Sumarski List Hrvatskoga Sumarskoga Drustva is the property of Forestry Society of Croatia and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Norway maple (Acer platanoides L.) is a key species of broadleaved forests whose population genetics is poorly studied using modern genetic tools. We used ISSR analysis to explore genetic diversity and differentiation among 10 Russian populations on the eastern margin of the species range of distribution, and to compare the revealed patterns with the results of our population genetic studies of pedunculate oak (Quercus robur L.). In the first set comparatively high heterozygosity and allelic diversity were found (expected heterozygosity HE = 0.160 ± 0.033, number of alleles na = 1.440 ± 0.080, effective number of alleles ne = 1.271 ± 0.062) in comparison with strongly fragmented and geographically isolated small maple stands of the second set (HE = 0.083 ± 0.011, na = 1.281 ± 0.031, ne = 1.136 ± 0.019). A relatively high genetic differentiation among populations was detected (the proportion of the inter-population component of total genetic variation, GST = 0.558 ± 0.038). In the Cis-Urals, local groups of populations that are confined to the northern, middle and southern parts of the Urals were identified. On the contrary, the current significant fragmentation of the pedunculate oak distribution area in the same study area did not lead to any noticeable genetic differentiation among the majority of populations, the values of the population genetic diversity were very similar in different parts of the Southern Urals. [ABSTRACT FROM AUTHOR]

Subfossil wood is a valuable and rare material often used for production of expensive furniture and decorative artistic items of unique beauty. Its mechanical and tribological properties are still being studied and are considered specific due to the particular conditions of its long-lasting formation in aqueous sediment sludge. Various elements that have been impregnated into the wood tissue over many years make the machining and grinding of this type of wood rather difficult compared to normal recent wood. The main objective of this study was to determine the influence of the abrasive grain size of sandpaper on the abrasion volume loss of recent and two subfossil oak samples in three characteristic sections (cross, radial, and tangential). The results showed that the average size of abrasive grains and the orientation of the wood structure have an influence on the abrasion volume loss of all three samples. The phenomenon of the critical size of abrasive grains was observed in all samples and on all sections. As the size of abrasive grains increased to the critical size, the abrasive volume loss of the sample increased simultaneously. The lowest abrasion volume loss was observed on recent oak. In all samples, the lowest volume loss was measured on the cross sections, and the tangential and radial sections had mutually equal values. It was also found that the increase in the size of abrasive grains to a critical value resulted in the increasing value of the absolute difference between the abrasion volume loss of the cross, radial, and tangential section samples, while the relative relations between the abrasive volume loss values of three different sections (C/R, C/T, R/T) within the same grit of sandpaper remained quite similar.

Introduction: Two species of oak are dominant in French forests: pedunculate oak (Quercus robur L.) and sessile oak (Quercus petraea Liebl.). Differentiating oak species is difficult, since features such as morphological characters, geographical origin and grain are not always relevant. Even if the former is generally richer in tannin compounds while the latter is often richer in aromatic compounds, the intra‐species variability is high. The characterisation of the oak species remains a suitable indicator of the molecular composition and quality of the wood. Objectives: The aim of this study was to determine differentiating molecules allowing oak species identification in order to assist in a suitable wood selection for a better oak tree valorisation since the selection of the oak wood to be used in the production of barrels plays an essential role in wine ageing. Materials and Methods: Oak wood samples were collected both in forests and in cooperage timber yards. An untargeted metabolomic approach using ultra‐high‐pressure liquid chromatography qualitative time‐of‐flight high‐resolution mass spectrometry (UHPLC‐Q‐TOF‐HRMS) associated to multivariate statistical analyses (hierarchical ascendant clustering and partial least squares discriminant analysis) was implemented to determine molecular markers of oak species. Results: Heartwood was identified as the suitable wood part to distinguish oak species. Discriminating molecules did not depend on the sample set. The pedunculate species showed overexpression of bartogenic derivatives while sessile oak presented a higher content in oak lactone precursors and in quercotriterpenosids. Conclusion: The developed method allowed the identification of relevant compounds for oak species identification to a better wood valorisation and selection. The determination of the oak species is difficult, since features such as morphological characters, geographical origin and grain are not always relevant. However it remains a very relevant indicator of wood quality and molecular composition. Thus, an untargeted metabolomic approach using UHPLC‐Q‐Tof‐HRMS associated to multivariate statistical analyses was implemented to determine discriminant molecules of oak species. The pedunculate species showed overexpression of bartogenic acid derivatives while sessile oak presented a higher content in oak lactone precursors and in quercotriterpenosids. [ABSTRACT FROM AUTHOR]