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Quercus suber woodlands are widely distributed around the Western Mediterranean basin. Although assumed well-adapted to recurrent seasonal droughts, water availability during critical phases can limit Q. suber crown development and, consequently, photoassimilate production and growth. This work aims to assess the relationships between climate conditions and seasonal and interannual variation of multiple vegetative and reproductive growth traits in Q. suber and identify possible mechanisms governing within-tree competition for resources and trade-offs between vegetative and reproductive growth. Data collection occurred between 2010 and 2019 and involved the monthly monitoring of reproductive and vegetative phenology, stem radial growth, and litterfall collection in a Q. suber woodland in central Portugal. Winter and autumn precipitation reductions (20 and 30%, respectively) during 2015–2019 resulted in a 23% decrease in leaf biomass production (compared to 2010–2014). Results show that mean March temperatures have a pivotal role in balancing vegetative/reproductive biomass investment, being positively correlated with the growth of vegetative structures (r = 0.81) and negatively correlated with acorn production (r=-0.83). PCA results also confirm the existence of competitive interaction between reproductive and vegetative growth in Q. suber trees, with mast cropping years resulting in reductions in annual leaf biomass production (26%). Dry years affected annual stem radial growth negatively (ca. 48%), reducing the period of phellogen activity and anticipating annual radial growth peaks by two months, consequently shortening the window for a safe cork extraction. Our results provide valuable information to adapt the management of Q. suber woodlands to ongoing environmental changes and contribute to ecosystem sustainability. [ABSTRACT FROM AUTHOR]

This study focuses on the effect of differences in acorn dropping time on seedling establishment in two abundant Mediterranean oak species: Quercus ilex subsp. ballota and Q. suber. These species show extended seed dropping seasons (i.e., 4 to 5 months) and the fallen acorns thus experience variable conditions, including differences in climate and microclimate, as well as differences in biological interactions (mainly pre- and post-dispersal predation by insect larvae and rodents, respectively). We conducted two field experiments and a field survey on acorn infection by insect larvae and analysed the ability of early and late dropped acorns to achieve success (i.e., remaining healthy, germinating, and emerging as seedlings). The results indicated that pre- and post-dispersal predation of propagules changed over time. However, these factors had low effect on final seedling success. In opposition, warmer (i.e., autumn) conditions at acorn dropping and sowing time decreased seedling establishment in Q. suber, likely by a lack of cold stratification, while the conditions had no effect on Q. ilex subsp. ballota seedlings. We conclude that climate warming can selectively decrease the number of seedlings that are established in late springtime, before the onset of the characteristic Mediterranean summertime drought, thus negatively affecting the population dynamic in these species, which exhibit a high level of physiological dormancy as they depend on cold conditions to maximise acorn germination and epicotyl emergence. [ABSTRACT FROM AUTHOR]

BackgroundAimsMethodsResultsConclusionCork oak (Quercus suber) forests and woodlands cover an area of ca. 2.1 M ha in the Mediterranean Basin. Cork oak stands are important for biodiversity conservation, and ecosystem services (carbon storage and the provision of cork, timber, and firewood). Their sustainable management is essential for their continued multifunctional existence and for providing ecosystem services.The aims of this study were to estimate the biomass production of the species and quantify its potential carbon storage capacity in the Mediterranean Basin and to make management recommendations.We used a literature survey of allometric equations and cork annual total tree-ring growth data and applied them to determine the productivity of the species. Estimate biomass by using regression models and dendrometric characteristics is very important for cork oak in the Mediterranean region.The studies reported a wide-ranging above-ground biomass for cork oak: 42 Mg ha−1 for Italy, 64–120 Mg ha−1 for Morocco, 41–50 Mg ha−1 for Portugal, 29–328 Mg ha−1 for Spain, and 80–312 Mg ha−1 for Tunisia. The radial wood increment ranged from 0.78 to 8.01 mm yr−1. The annual increment of cork-ring growth was between 0.8 mm yr−1 (northern Algeria) and 5.25 mm yr−1 (Spain), with most values being between 2 and 4.4 mm yr−1. In dry years, major reductions (10−15%) in the growth of Quercus suber were observed.Most studies showed stand-specific growth responses to climate variables, with the radial growth of cork oak being greater in relatively mesic and cool conditions. [ABSTRACT FROM AUTHOR]

Studies have reported the important role of soil properties in regulating insect herbivory under controlled conditions or at relatively large scales. However, whether fine‐scale variation of soil properties affects insect herbivory under natural conditions in forests is still unclear. We selected a ca. 300 ha Quercus variabilis forest area where the leaf damage was mainly caused by Lampronadata cristata (Lepidoptera: Notodontidae) and set 200 10 × 10 m plots within the area. We examined insect herbivory (percent leaf area damaged) on Q. variabilis and correlated it to soil properties and tree characteristics. Insect herbivory decreased with soil sand percentage and bulk density and increased with DBH and tree height. Effects of soil sand percentage and bulk density on insect herbivory were partly mediated by DBH and tree height. Our results indicated that soil physical properties may have significant effects on insect herbivory by directly influencing insect herbivores that need to complete their life cycle in the soil, or by indirectly affecting insect herbivores through influencing DBH and tree height which reflects the total leaf biomass available to the insect herbivore. This study may help to understand the complex relationship between soil and plant–insect interactions in forest ecosystems. [ABSTRACT FROM AUTHOR]

Reducing energy consumption in the building sector has driven the search for more sustainable construction methods. This study explores the potential of cork-modified mortars reinforced with basalt fabric, focusing on optimizing both mechanical and hygroscopic properties. Six mortar mixtures were produced using a breathable structural mortar made from pure natural hydraulic lime, incorporating varying percentages (0–3%) of cork granules (Quercus suber) as lightweight aggregates. Micro-computed tomography was first used to assess the homogeneity of the mixtures, followed by flow tests to evaluate workability. The mixtures were then tested for water absorption, compressive strength, and adhesion to tuff and clay brick surfaces. Adhesion was measured through pull-off tests, to evaluate internal bonding strength. Additionally, this study examined the relationship between surface roughness and bond strength in FRLM composites, revealing that rougher surfaces significantly improved adhesion to clay and tuff bricks. These findings suggest that cork-reinforced mortars offer promising potential for sustainable construction, achieving improved hygroscopic performance, sufficient mechanical strength, internal bonding, and optimized surface adhesion. [ABSTRACT FROM AUTHOR]

This study discovers the distribution of vegetation in the Sougna Mountain and its modern pollen representation and investigates the relationships with environment and land use variables. A total of 31 moss polsters were collected between 138 and 1364 m above sea-level from wooded to open areas (e.g. cork oak forest, pine reforestation, and shrubland). At each sampling site land use and environment variables were collected. The vegetation in the Sougna Mountain is scattered in a mosaic along three vegetation belts which are displayed in distinct pollen assemblages dominated by the pollen equivalents of the vegetation types (Quercus suber forest, matorrals of Erica spp. and Cistus spp. and Pinus pinaster reforestation). The variation between the variables and pollen data was performed using CCA analysis. The anthropogenic variables such as grazing, and cultivation, contribute to discrimination of the degraded and grazed areas. High precipitation and altitude have a rather good correlation to wooded communities and consequently a good relation to the tree cover. Our results show that the pollen types of Poaceae, Cannabis, Plantago, Nicotiana, Asteraceae, and Urtica are related mostly to human practice and distinguish the disrupted communities. The presence of those taxa in the pollen diagram must be interpreted carefully. A high taxonomic resolution is recommended to prevent the overestimation of the abundance of some taxa. Our results contribute to the advancement of palynological reconstructions of past vegetation and land use in Sougna Mountain and generally in the Rif landscape. [ABSTRACT FROM AUTHOR]

Mycorrhizal associations play a pivotal role in maintaining Mediterranean maquis and xerophilous grasslands, thereby contributing to erosion prevention and desertification mitigation in arid and semi-arid regions. The present study aims to elucidate this plant-fungus relationship to ensure the ecological restoration of Quercus suber (Q.s.), by exploring mycorrhizal colonization rates under diversified experimental conditions. The data reveal an absence of mycorrhizal colonization in the negative control group (Q.s.), while the positive control group (Q.s. + Terfezia (T) spp.) exhibits a significant colonization rate of 15.2 ± 6.2%. More notably, the Q.s. + T + Helianthemum guttatum (H.g.) and Cistus salviifolius (C.s.) group displays the highest colonization rate at 47.0 ± 8.4%, suggesting advantageous synergy among Helianthemum guttatum, Cistus salviifolius, and Quercus suber. This observation is supported by seedling growth data, wherein groups with increased colonization demonstrate greater aboveground height. Particularly, the Q.s. + T + H.g. + C.s. group shows a height of 12.0 ± 3.0 cm, illustrating the beneficial impact of these symbiotic associations on cork oak seedling development. Furthermore, chemical analysis of soils from the Maâmora forest provides relevant insights into conditions conducive to Quercus suber ectomycorrhization. Moderately acidic pH values, low calcium carbonate content, as well as appropriate levels of organic matter, carbon, nitrogen, phosphorus, and potassium characterize these soils. In addition to these data, microscopic examination of roots confirms the presence of Terfezia spp. hyphae, indicating mycorrhizal formation without the characteristic structures of ectomycorrhizae. This microscopic observation adds an additional dimension to our understanding of the complex interactions among host plants, mycorrhizal fungi, and soil properties. [ABSTRACT FROM AUTHOR]

We introduce a novel methodological framework for robust trend analysis (RTA) using remote sensing data to enhance the accuracy and reliability of detecting significant environmental trends. Our approach sequentially integrates the Theil–Sen (TS) slope estimator, the Contextual Mann–Kendall (CMK) test, and the false discovery rate (FDR) control. This comprehensive method addresses common challenges in trend analysis, such as handling small, noisy datasets with outliers and issues related to spatial autocorrelation, cross-correlation, and multiple testing. We applied this RTA workflow to study tree cover trends in Los Alcornocales Natural Park (Southern Spain), Europe's largest cork oak forest, analysing interannual changes in tree cover from 2000 to 2022 using Terra MODIS MOD44B data. Our results reveal that the TS estimator provides a robust measure of trend direction and magnitude, but its effectiveness is dramatically enhanced when combined with the CMK test. This combination highlights significant trends and effectively corrects for spatial autocorrelation and cross-correlation, ensuring that genuine environmental signals are distinguished from statistical noise. Unlike previous workflows, our approach incorporates the FDR control, which successfully filtered out 29.6% of false discoveries in the case study, resulting in a more stringent assessment of true environmental trends captured by multi-temporal remotely sensed data. In the case study, we found that approximately one-third of the area exhibits significant and statistically robust declines in tree cover, with these declines being geographically clustered. Importantly, these trends correspond with relevant changes in tree cover, emphasising the ability of RTA to detect relevant environmental changes. Overall, our findings underscore the crucial importance of combining these methods, as their synergy is essential for accurately identifying and confirming robust environmental trends. The proposed RTA framework has significant implications for environmental monitoring, modelling, and management. [ABSTRACT FROM AUTHOR]

Biscogniauxia mediterranea is a pathogenic fungus associated with Quercus species causing charcoal canker disease in forests. Its phenotypic and genetic variability has been well studied in Tunisia but little is known about its demographic history. Population dynamic of B. mediterranea was evaluated among 30 isolates from different cork oak forests in Northwestern Tunisia. The genetic structure analyzed with two DNA markers (ITS and tef-1α) showed low genetic differentiation associated with high genetic flow among populations. The polymorphism analysis showed low nucleotide diversity but high haplotypic diversity among and within B. mediterranea populations which could be due to rapid growth from a small ancestral population. This hints at recent population growth after a period of decline likely due to a catastrophic event involving fires and human-induced tree cutting. The resulting genetic diversity within populations primarily arises from the emergence of new haplotypes. Overall, this study provides insights into the polymorphism of B. mediterranea and its potential adaptive strategy. [ABSTRACT FROM AUTHOR]

The investigated Iberian cork oak forests represent one of the ecosystems of greatest interest in the Iberian Peninsula, not only because of the ecosystem services they provide, but also because they are unique habitats in Europe and North Africa (habitat 9330). Due to the interest, they present, we carried out this study in order to obtain as exhaustive knowledge as possible, and to be able to offer environmental managers more information. We examined 12 cork oak associations in the Iberian Peninsula, both in their floristics, ecology and distribution as well as in terms of their dynamics, and we discovered that there are climaxes of Quercus Suber whose dynamics have not been established. We make a name correction because the name of the taxon used for the binomen Junipero badiae- Quercetum suberis Rivas-Martínez et al. 2002 nom corr, is not valid. We also propose the correction of the name of the association Cheirolopho sempervirentis-Quercetum suberis Pérez Latorre, Cabezudo in Pérez Latorre et al. 2008 nom. corr. The dynamics for the Cheirolopho sempervirentis-Quercetum suberis cork oak forest and the Cheirolopho sempervirentis-Arbutetum unedonis nova and Bupleuro gibraltarici-Quercetum suberis nova associations, and two plant communities are described. Based on the results obtained and the ICPN mandate, we propose to synonymize Oleo sylvestris-Quercetum suberis Rivas Goday, Galiano & Rivas-Martínez ex Rivas-Martínez 1987= (syn: Aro neglecti- Quercetum suberis Rivas-Martínez & Díez Garretas 2011). [ABSTRACT FROM AUTHOR]

Irrigation can be a strategy to overcome the high mortality and declining vigour of cork oak trees facing increasing drought stress in the Mediterranean basin. Through a three-year irrigation experiment in a semi-arid Mediterranean region, which encompassed two sets of 100 planted individuals that had a 24-year age gap and the direct seeding of 100 acorns, we tested the influence of water irrigation on distinct stages of cork oak establishment and development, namely (1) acorn germination, (2) emerged seedling survival, (3) growth of planted seedlings, (4) vertical and (5) radial growth, and (6) the vigour of 28-year-old trees. Water irrigation significantly improved acorn germination and the growth of both cork oak seedlings and trees but did not affect the survival of emerged seedlings to the dry season. The vigour of 28-year-old trees (height-to-diameter ratio) showed no significant differences between the plants growing in watered and in controlled conditions. [ABSTRACT FROM AUTHOR]

Featured Application: This study on aluminum phosphate nanoparticles (AlPO4NPs) synthesized through green methods has significant implications for advancing nanomaterial synthesis with sustainable practices. By utilizing phytates extracted from Quercus suber somatic embryos, the green synthesis approach not only provides a natural precursor for nanoparticle formation but also emphasizes the environmental benefits of using plant-derived materials. The synthesized aluminum phosphate nanoplates, characterized by their unique optical and structural properties, show promising potential applications. This research paves the way for further innovations in nanotechnology and environmental biotechnology, highlighting the role of sustainable methods in the production of high-value nanomaterials. This study presents a novel green synthesis method for aluminum phosphate (AlPO4) nanoplates using extracts from Quercus suber somatic embryos. Traditionally, metallic nanoparticles are synthesized using harmful chemical reagents and solvents, but our approach leverages bioactive compounds, such as phytic acid (IP6) from plant extracts, offering a more sustainable alternative. We observed a high phosphate content of 23.6 μMol PO43−/mg dry weight (DW) in the extracts, which is significantly higher than in other Quercus species. Characterization through UV–VIS spectroscopy and XRD confirmed the formation of complex crystal nanoplates, where anisotropic aluminum phosphate with a triclinic crystal structure coexists with monoclinic structures, both forms of aluminum phosphate tridymite. Electron microscopy (TEM and SEM) revealed the hierarchical organization of these nanoplates, distinguishing them from the more commonly observed spherical nanoparticles. Fourier-transform infrared (FTIR) spectroscopy further validated the incorporation of phytic acid into the nanoplate structure. This innovative method not only advances sustainable nanomaterial synthesis but also demonstrates the potential for unique optical and structural properties in aluminum phosphate nanoplates, paving the way for future applications in specialized fields. [ABSTRACT FROM AUTHOR]

Turkey oak (Quercus cerris L.) is one of the most ecologically and economically significant deciduous tree species in the Central and Southeast European regions. The species has long been known to exhibit high levels of genetic and phenotypic variation. Recent climate response predictions for Turkey oak suggest a significant distribution extension in Europe under climate change. Since Turkey oak has relative drought-tolerant behaviour, it is regarded as a potential alternative for other forest tree species during forestry climate adaptation efforts, not only in its native regions but also in Western Europe. For this reason, the survey of existing genetic variability, genetic resources, and adaptability of this species has great significance. Next-generation sequencing approaches, such as ddRAD-seq (Double digest restriction-site associated DNA sequencing), allow the attainment of high-resolution genome-wide single nucleotide polymorphisms (SNPs). This study provides the first highly variable genome-wide SNP data for Turkey oak generated by ddRAD-seq. The dataset comprises 17 607 de novo and 26 059 reference mapped SNPs for 88 individuals from eight populations, two from Bulgaria, one from Kosovo, and five from Hungary. Reference mapping was carried out by using cork oak's (Quercus suber L.) reference genome. The obtained high-resolution genome-wide markers are suitable for investigating selection and local adaptation and inferring genetic diversity, differentiation, and population structure. The dataset is accessible at: https://doi.org/10.5281/zenodo.8091252 [ABSTRACT FROM AUTHOR]

Climate change is having an impact on locally adapted species, including the cork oak (Quercus suber L.), a key tree species in the Mediterranean region especially due to its role in carbon sequestration. Notably, the Maâmora forest in Morocco stands as the largest forest in the Mediterranean basin with the highest diversity compared to similar forests across Morocco. In this study, we genotyped 240 samples from natural populations of cork oak in the Maâmora forest using seven microsatellite markers, to investigate signatures of local adaptation. Using a genomic scan approach, we identified outliers loci experiencing divergent natural selection pressures, which were later correlated with climatic, edaphic, and geographic conditions of the Maâmora forest. Statistical analysis of the data shows a high allelic variation. The detection of outliers, carried out using BayeScan v2.1 software, revealed the presence of two significant outliers loci ZAG20-171 (qvalue = 0.0004) and MSQ4-211 (qvalue = 0.04). The result of the environmental association analysis revealed a significant correlation between locus ZAG20-171 with mean diurnal range, isothermality, annual precipitation, precipitation of the driest month, precipitation of the wettest quarter and altitude. This work aims to help understanding the genetic basis of adaptation in Q. suber L., and thus the selection of suitable provenances for further breeding efforts. [ABSTRACT FROM AUTHOR]

Rainfall redistribution plays a crucial role in the water cycle. However, the main factors affecting the redistribution of rainfall remain uncertain. We chose three different plantations—cork oak (Quercus variabilis Bl.), oriental arborvitae (Platycladus orientalis L.) and black locust (Robinia pseudoacacia L.)—to investigate the role of plantations in rainfall redistribution and to determine the main factors influencing rainfall redistribution. The results indicated that cork oak exhibited the highest stemflow (0.34%) and the lowest canopy interception (12.58%), whereas black locust had the lowest stemflow (0.21%), and oriental arborvitae displayed the greatest canopy interception (32.8%). Under different density conditions for cork oaks, the stemflow was highest (0.39%) in low‐density forests with 750 trees ha−2 and lowest (0.34%) in medium‐density forests with 1100 trees ha−2. Meanwhile, the highest canopy interception (17.68%) was observed in high‐density forests (1300 trees ha−2), while the lowest interception rate (9.22%) was found in low‐density forests. The main factors affecting rainfall redistribution and their contribution rates were as follows: bark roughness index (35%), wind speed (18.6%), tree species (14.2%), diameter at breast height (11.2%), stand density (9.6%) and rainfall amount (5.4%). Our findings suggested that structural characteristics of trees are the primary factors affecting rainfall redistribution. Planting cork oak in the rocky mountain regions of North China is recommended because of its substantial stemflow production, particularly under low‐density growth conditions. Therefore, this study has significant guiding implications for the selection of afforestation tree species in similar rocky mountain areas globally. [ABSTRACT FROM AUTHOR]

The bio‐based methacrylates 9‐(methacryloyloxy)‐10,18‐dihydroxyoctadecanoic acid/9,18‐dihydroxy‐10‐(methacryloyloxy)octadecanoic acid isomer mixture and 22‐methacryloyloxydocosanoic acid were synthesized from 9,10‐epoxy‐18‐hydroxyoctadecanoic acid and 22‐hydroxydocosanoic acid. The white crystalline 9,10‐epoxy‐18‐hydroxyoctadecanoic acid and cream‐colored 22‐hydroxydocosanoic acid were isolated from both the bark of Betula pendula and cork of Quercus suber after extraction of the milled plant materials with methanol, treating the insoluble residues with 2‐propanole containing suspended sodium hydroxide, application of a working up procedure developed in this work for the resulting mixture, and purification of the products obtained. The new bio‐based methacrylates show higher reactivity in the photoinitiated polymerization in comparison with the commercial laurylmethacrylate as detected by photo‐differential scanning calorimetry (DSC). For comparison, traditional free radical polymerization of the new bio‐based methacrylates was carried out in dimethylsulfoxide using 2,2'‐azobis‐(2‐propionitrile) as initiator. Furthermore, the quantitative conversion of the bio‐based monomers during the photoinitiated polymerization makes these bio‐based monomers interesting for application in coatings. As expected, the photopolymer made from the 9‐(methacryloyloxy)‐10,18‐dihydroxyoctadecanoic acid/9,18‐dihydroxy‐10‐(methacryloyloxy)octadecanoic acid isomer mixture is amorphous. Interestingly, the photopolymer made from the 22‐methacryloyloxydocosanoic acid contains crystalline structures as detected by DSC investigation. [ABSTRACT FROM AUTHOR]

Increasing water contamination from metal cations is a significant environmental challenge for humans. This has sparked extensive research into the development of adsorbents with superior removal efficiencies. This study assessed the adsorption capacity of crude and lignocellulosic fractions obtained from the pericarp of Quercus suber acorns, specifically focusing on the removal of Pb(II), Cd(II), Ni(II), and Cu(II) ions from aqueous solutions. The lignocellulosic fraction was separated from the crude fraction after extraction of cell wall polysaccharides using water and alkaline solutions. Scanning electron microscopy (SEM) and Fourier transform infrared spectroscopy (FTIR) were used to characterize the crude and lignocellulosic fractions. Data from equilibrium adsorption experiments were analyzed using the Langmuir and Freundlich isotherm models. The study found that the lignocellulosic fraction removed Pb(II) ions more efficiently than the crude fraction, with qmax values of 500.0 mg.g−1. Crude fractions exhibited a considerable retention potential for Cd(II), Ni(II), and Cu(II) ions with qmax values of 95.2 mg.g−1, 333.3 mg.g−1 and 200 mg.g−1 respectively. Crude and lignocellulosic fractions extracted from the acorn Q. suber pericarps could be environmentally friendly biosorbents for the removal of metal cations from aqueous solutions. [ABSTRACT FROM AUTHOR]

Abstract In recent decades an extensive mortality and decline of Quercus suber populations mainly caused by Phytophthora cinnamomi has been observed. In the current study, a chestnut gene homologous to ginkbilobin-2 (Cast_Gnk2-like), which in Ginkgo biloba codifies an antifungal protein, was transferred into cork oak somatic embryos of three different embryogenic lines by Agrobacterium mediated transformation. The transformation efficiency varied on the genotype from 2.5 to 9.2%, and a total of 22 independent transformed lines were obtained. The presence of Cast_Gnk2-like gene in transgenic embryos was verified in all lines by PCR. The number of transgene copies was estimated by qPCR in embryogenic lines with high proliferation ability and it varied between 1 and 5. In addition, the expression levels of Cast_Gnk2-like gene were determined in the embryogenic lines, with higher levels in lines derived from the genotype ALM6-WT. Transgenic plants were obtained from all transgenic lines and evaluated after cold storage of the somatic embryos for 2 months and subsequent transfer to germination medium. In vitro tolerance tests made under controlled conditions and following zoospore treatment showed that plants overexpressing Cast_Gnk2-like gene improved tolerance against Pc when compared to wild type ones.

This study investigates the enhanced production of key therapeutic metabolites (ellagic acid, serotonin, and chlorogenic acid) in response to abiotic stress in in vitro cultures of Quercus suber somatic embryos. Findings indicate significant increases in metabolite levels under various stress conditions, highlighting the potential for commercial-scale production of these compounds, known for their antioxidant, anticancer, and anti-COVID-19 properties. Under osmotic/saline stress, ellagic acid production significantly increased, representing an 80% increase compared to control conditions. In embryos exposed to different stressors, serotonin accumulation showed a six-fold increase under osmotic/saline stress. Although the elicitors used did not increase chlorogenic acid levels, exploring alternative stress types may enhance its production. This research paves the way for sustainable, large-scale production of health-beneficial metabolites, addressing global health challenges and promoting resource sustainability. [ABSTRACT FROM AUTHOR]

Seasonality in temperate regions is prominent during the era of increased climatic variability. A hydraulic trait that can adjust to seasonally changing climatic conditions is crucial for tree safety. However, little attention has been paid to the intraspecific seasonality of drought-related traits and hydraulic safety of keystone forest trees. We examined seasonal variations in the key morphological and physiological traits as well as multiple hydraulic safety margins (SMs) at the branch and leaf levels in oriental cork oak (Quercus variabilis Bl.), which is predominant in Chinese temperate forests. Pneumatic measurements indicated that, as seasons progressed, the water potential at which 50% of branch embolisms occur (P 50_branch) decreased from −3.34 to −4.23 MPa, with a coefficient of variation (CV) of 9.08%. Sapwood capacitance ranged from 48.19 to 248.08 kg m−3 MPa−1, peaking in autumn and reaching minimum in winter (CV 60.58%). Rehydration kinetics confirmed higher leaf embolism vulnerability (P 50_leaf) in spring and autumn than those in summer, with values ranging from −1.06 to −3.02 MPa (CV 39.85%). All leaf pressure–volume (PV) traits shifted with growth, with CVs ranging from 6.95% to 46.69%. Sapwood density had significant negative correlations with P 50_branch and hydraulic capacitance for elastic water storage, whereas leaf mass per area was linearly associated with PV traits but not with P 50_leaf. Furthermore, the branch typical SMs (difference between branch midday water potential and P 50_branch) were consistently >1.84 MPa, and vulnerability segmentation was prevalent throughout, implying a plausible hydraulic foundation for the dominance of Q. variabilis. Diverse hydraulic response patterns existed across seasons, leading to positive SMs mediated by the aforementioned physiological traits. Although Q. variabilis exhibits a high level of hydraulic safety, its susceptibility to sudden summer droughts may increase due to global climate change. [ABSTRACT FROM AUTHOR]

Cork oak (Quercus suber L.) mortality has reached alarming proportions in the last decades, exacerbated by climate change. Understanding this phenomenon is crucial in finding mitigation or adaptation strategies. This study conducts a diachronic analysis of cork oak mortality over 10 years using GIS (Geographic Information Systems) tools, focusing on Portugal's Tagus Lezíria region. Topographic, edaphic and climatic variables were employed to create maps of edaphoclimatic aptitude for cork oaks. Dead trees were identified using remote sensing techniques and crown coverage was determined to calculate the trees' mortality index. The diachronic analysis aimed the exploration of climate change effects on cork oak mortality. A decrease in precipitation was observed, significantly impacting stands with canopy cover below 40%. Furthermore, a negative effect of solar radiation identified only in stands with canopy cover of 40% suggested its role in cork oak decline. This study introduces a novel perspective, highlighting the protective effect of denser canopy cover against excessive solar radiation and the impact of reduced precipitation. The integrated and diachronic approach provides valuable information for adapting management strategies to climate change challenges. [ABSTRACT FROM AUTHOR]

The article describes the groundbreaking new ingredient Shiloxome ™, developed by Provital, which counteracts signs of aging and protects the skin in a multi-omic way. The ingredient is derived from the endophytic yeast Kwoniella mangroviensis and acts as a protective shield for the skin. Provital has developed a technology that allows them to isolate endophytic strains and investigate their bioactivity. The first developed ingredient, Shiloxome ™, comes from the endophytic yeast species Kwoniella mangroviensis found in the bark of the cork oak. This ingredient protects the skin and gives it the ability to adapt and survive. Provital has also conducted a study on the effectiveness of the ingredient, which has shown that it protects the skin from environmental stressors and improves the integrity of the skin barrier. The active ingredient has a positive effect on the overall chain length of the lipidome and strengthens the permeability barrier of the skin. Signal pathways related to the structure and organization of the extracellular matrix have been identified. The active ingredient also has a significant effect on the remodeling and overall condition of the skin structure and function. An improvement in elastin and collagen I levels has been observed. The results show that the active ingredient strengthens the lipid barrier and contributes to the restoration of youthful and healthy skin. The article describes a new active ingredient called Shiloxome ™, developed by Provital. The active ingredient is based on endophytes and is produced using the Triplobiome ™ technology. Shiloxome ™ offers benefits in the fight against skin aging and restructures the skin barrier. It has been shown that the active ingredient reduces lipid oxidation and provides comprehensive skin protection. Shiloxome ™ is recommended as a powerful ally for resilient, youthful skin. [Extracted from the article]

In north-western Algeria (Tlemcen), we collected morphologically mature acorns separately from 17 trees, and another quantity was collected from the ground in the mountain cork oak forests: Hafir and Zariefet. The germination rate of healthy (H) and slightly damaged (S) acorns reaches 100%. The lowest emergence rates are observed in severely damaged acorns (Sd) (8%), with differences between producing individuals (the maximum recorded for Sd is 67%). The survival rate of plants varies in the same way as the emergence rate: 100% in (H) and 93% in (S). The survival score of (Sd) is 57%. These acorns can continue to produce young seedlings until the embryo is completely wiped out. However, more than 90% of the (Sd) of 64% of the trees remain metabolically inactive. In western Algeria, the 60% decrease in the germination rate of (Sd) seems to be linked to the acorns small size, which are approximately half of those in eastern Algeria. Depredation of acorns by insects hardly affects the growth of young seedlings in the first days of their development, but occurs much later, depending on the physiological integrity of the almond, cotyledonary mass and quality, and the infestation intensity. [ABSTRACT FROM AUTHOR]

Light use efficiency (LUE) characterizes the efficiency of vegetation in converting photosynthetically active radiation (PAR) into biomass energy through photosynthesis and is a critical parameter for gross primary productivity (GPP) in terrestrial ecosystems. Based on the eddy covariance measurements of a Chinese cork oak plantation ecosystem in northern China, the temporal variations in LUE were investigated, and biophysical factors were examined at time scales ranging from hours to years. Our results show that diurnal LUE first increased sharply before 8:30 and then decreased gradually until 12:00, thereafter increasing gradually and reaching the maximum value at sunset during the growing season. The daily and monthly LUE first increased and then decreased within a year and showed a substantial drop around June. The annual LUE ranged from 0.09 to 0.17 g C mol photon−1, and the multiyear mean maximal LUE was 0.30 g C mol photon−1 during 2006–2019. Only GPP (positive) and clearness index (CI) (negative) had consistent effects on LUE at different time scales, and the effects of the remaining biophysical factors on LUE were different as the time scale changed. The effects of air temperature, vapor pressure deficit, precipitation, evaporative fraction, and normalized difference vegetation index on LUE were mainly indirect (via PAR and/or GPP). When CI decreased, an increased ratio of diffuse PAR to PAR produced a more uniform irradiance in the canopy, which ultimately resulted in a higher LUE. Due to climate change in our study area, the annual LUE may decrease in the future but improving management practices may slow or even reverse this trend in the annual LUE in the studied Chinese cork oak plantation. [ABSTRACT FROM AUTHOR]

Local terrain or microsite conditions influence the development of trees, particularly at early ages. These conditions might be described by edaphic or topographic variables. We mapped soil and topographic variables from four even-aged and even-spaced cork oak plantations located in two climatically distinct Portuguese regions. The major goal of this research was to understand the relation between soil and topographic fine-scale conditions and tree growth expressed by diameter without cork annual growth (idu). The methodology consisted in (1) analysing the spatial variability and autocorrelation of idu; (2) modelling idu with ordinary least squares (OLS) regressions; (3) comparing with spatial modelling of idu, incorporating spatial autocorrelation. The driest stands A and B, exhibited weaker spatial autocorrelation, distributed in smaller clusters (R2 < 0.03, OLS models), while stands C (R2 = 0.18, OLS models) and D (R2 = 0.11, OLS models) showed higher predictive capacity. Spatial models increased R2 scores, keeping most variables from OLS models and accounting for spatial autocorrelation. A + B + C + D OLS model obtained an R2 = 0.34 and respective spatial model R2 = 0.58. Apparent electrical conductivity at 0.5 (ECa0.5) and 1 m of soil depth, slope, elevation and topography position index were included as predictors (OLS), but only ECa0.5, slope and elevation were selected in the spatial model. Models were fitted using average to high productivity stands and should be used cautiously outside this range. Local terrain conditions determine the growth of young cork oak trees. Mapping soil and topographic variables before establishing new plantations may identify limiting microsite conditions where using cork oak species is not suitable due to low growth rates expectations. [ABSTRACT FROM AUTHOR]

In recent decades an extensive mortality and decline of Quercus suber populations mainly caused by Phytophthora cinnamomi has been observed. In the current study, a chestnut gene homologous to ginkbilobin-2 (Cast_Gnk2-like), which in Ginkgo biloba codifies an antifungal protein, was transferred into cork oak somatic embryos of three different embryogenic lines by Agrobacterium mediated transformation. The transformation efficiency varied on the genotype from 2.5 to 9.2%, and a total of 22 independent transformed lines were obtained. The presence of Cast_Gnk2-like gene in transgenic embryos was verified in all lines by PCR. The number of transgene copies was estimated by qPCR in embryogenic lines with high proliferation ability and it varied between 1 and 5. In addition, the expression levels of Cast_Gnk2-like gene were determined in the embryogenic lines, with higher levels in lines derived from the genotype ALM6-WT. Transgenic plants were obtained from all transgenic lines and evaluated after cold storage of the somatic embryos for 2 months and subsequent transfer to germination medium. In vitro tolerance tests made under controlled conditions and following zoospore treatment showed that plants overexpressing Cast_Gnk2-like gene improved tolerance against Pc when compared to wild type ones. [ABSTRACT FROM AUTHOR]

Hydrolyzable tannins (HTs) have garnered significant attention due to their proven beneficial effects in the clinical treatment of various diseases. The cupule of Chinese cork oak (Quercus variabilis Blume) has been used as raw material of traditional medicine for centuries for its high content of HTs. Previous studies have identified UGT84A13 as a key enzyme in the HT biosynthesis pathway in Q. variabilis, but the transcriptional regulation network of UGT84A13 remains obscure. Here, we performed a comprehensive genomewide identification of the TCP transcription factors in Q. variabilis, elucidating their molecular evolution and gene structure. Gene expression analysis showed that TCP3 from the CIN subfamily and TCP6 from the PCF subfamily were coexpressed with UGT84A13 in cupule. Further functional characterization using dual-luciferase assays confirmed that TCP3, rather than TCP6, played a role in the transcriptional regulation of UGT84A13, thus promoting HT biosynthesis in the cupule of Q. variabilis. Our work identified TCP family members in Q. variabilis for the first time, and provided novel insights into the transcriptional regulatory network of UGT84A13 and HT biosynthesis in Q. variabilis, explaining the reason why the cupule enriches HTs that could be used for traditional medicine. [ABSTRACT FROM AUTHOR]

Key Message: Leaves of seedlings from five oak species (Quercus robur L.; Q. pubescens L.; Q. suber L.; Q. afares Pomel; Q. ilex L.) displayed large, mainly inter-specific, differences in leaf mass-to-area ratio (LMA) and lignin content, as well as in the 13C composition of bulk leaf biomass. The variation in leaf lignin content and LMA did not impact the offset between the 13C composition measured in bulk leaf material versus soluble sugars. This observation, as well as the similar correlations between intrinsic leaf water use efficiency and the 13C compositions of bulk material or soluble sugars extracted from leaves, confirms their reliable use as a proxy for the former even when there is a large variation in LMA or lignin among samples. Context: Carbon isotope composition (δ13C) of bulk leaf biomass is frequently used as a proxy for intrinsic water use efficiency (iWUE) in large-scale intra- and inter-specific comparisons. However, post-photosynthetic 13C discrimination during the synthesis of lignin combined with differences in leaf mass-to-area ratio (LMA) may bias the relationship between δ13C of bulk leaf matter and iWUE and thus its use as a proxy of iWUE. Aims: To quantify the impact of differences in lignin content and LMA on the relationship between δ13C of bulk leaf biomass and iWUE over a large gradient of lignin contents across five oak species (deciduous: Quercus robur, Q. pubescens, Q. afares and evergreen: Q. ilex and Q. suber). Methods: We measured lignin content, LMA, and δ13C of bulk leaf biomass and of soluble sugars extracted from the leaves, as well as intrinsic water use efficiency (derived from leaf gas exchange) in seedlings of the five oak species grown under common conditions in a greenhouse and measured in a climate chamber. Results: There was a large range (mainly across species) in lignin content (4 to 33%) and LMA (60–180 g m−2). δ13C of bulk leaf biomass and soluble sugars were tightly correlated, showing a significant mean offset of − 0.4‰. This offset was stable across species and not correlated to the lignin content of the leaves. A very loose correlation was found between the offset and LMA, mainly due to one species. Conclusion: Our results are a demonstration that potential variations in leaf lignin content or LMA have no or only a little effect on the δ13C of bulk leaf biomass. They are unlikely to cause a bias when using bulk leaf δ13C as a proxy for variations in intrinsic water use efficiency among Mediterranean and temperate broad-leaf forest tree species. [ABSTRACT FROM AUTHOR]

Mediterranean Quercus forests have great ecological importance but face numerous threats, including pests. The spongy moth, Lymantria dispar L., is a major oak defoliator across its geographical range and has a natural enemy complex that may control its population dynamics. This study aimed to investigate candidate predators (Coleoptera: Carabidae) and parasitoids (Hymenoptera: Encyrtidae, Ichneumonidae, Pteromalidae, Braconidae, Bethylidae, Ceraphronidae, Eulophidae, Eupelmidae and Trichogrammatidae; and Diptera: Tachinidae), for the control of L. dispar in two areas in Andalusia (Spain). We studied 10 Quercus stands (Q. suber, Q. ilex, and Q. pyrenaica), with different L. dispar infestation level. Insects were collected using pitfall and cross-vane traps, during the defoliator's larval period. Four genera comprised 92.2% of all the Carabidae predators found: Steropus Dejean (34.1%), Carabus L. (28.4%), Calathus Bonelli (15.9%), and Platyderus Stephens (13.8%); and four Hymenoptera families comprised 93.7% of the parasitoid specimens collected: Encyrtidae (61%), Ichneumonidae (17.5%), Pteromalidae (10.7%), and Braconidae (4.5%). Both the natural enemy assemblage composition and the abundance per tree varied between geographical areas, as well as between levels of defoliator infestation. The candidate enemy complex was markedly diverse and abundant in stands not infested by L. dispar, where no insecticides had been applied. Our results suggest the importance of generalist predators as natural enemies of L. dispar. [ABSTRACT FROM AUTHOR]

Cork oak woodlands are socio-ecosystems recognized as biodiversity hotspots, a fundamental economic source for companies and local communities as well as an identitarian landscape for residents and visitors. Cork oak woodlands, however, are facing tree mortality and lack of regeneration. Considering the oak decline scenario, we present Iberian cork oak montado/dehesa as a socio-ecosystem facing climate change, management transformations, local knowledge crisis and social uncertainty. We review montados/dehesas research through time and by different scholar perspectives. We defend that from an interdisciplinary and transdisciplinary perspective, including the experience and evidence observed in terrain, debate should be stimulated, and novel conceptual approaches may contribute to finding solutions. We argue that the confluence of ecology, genetics, anthropology and local knowledge can be explored to unveil the complexities and the challenges of these socio-ecosystems and contribute to prevent and mitigate threats to it. We propose a methodological approach built together with scientists, managers and workers, that can explore oak translocations, socio-ecological interactions models, knowledge transfer and other ways to overcome Iberian cork oak woodlands socio-environmental crisis. [ABSTRACT FROM AUTHOR]

Silvopastoral systems are widely used for ecological vegetation restoration in fragile areas. As the main landform of western Henan, the low hilly areas are experiencing water and soil loss because of human activities. However, the effect of silvopastoral systems on soil nutrients in low hilly areas has not been well studied. To address this issue, we established a silvopastoral experiment in the low hilly area of western Henan province in 2011, where four plots of pure forest of poplar (Populus simonii, PS), oriental thuja (Platycladus orientalis, PO), Chinese cork oak (Quercus variabilis, QV) and false acacia (Robinia pseudoacacia, RP) was planted on a natural wasteland; perennial alfalfa (Medicago sativa, MS) was intercropped with these pure forest plots as silvopastoral treatments, i.e., PS-MS, PO-MS, QV-MS and RP-MS; one plot of natural wasteland as CK. In 2018, 2019 and 2020, we examined the soil total carbon (TC) and total nitrogen (TN) of different vegetation restorations. Results showed that the silvopastoral treatments (PO-MS, QV-MS and RP-MS) generally increased the TC and TN (by ~ 53% and ~ 51% in 2018, ~ 66% and ~ 49% in 2019, and ~ 66% and ~ 67% in 2020, respectively) compared to the pure forest treatments, and were also higher than the M and PS-MS. The change in relative TC and TN between downslope and upslope positions is higher in PS and PO, lower in RP compared to the PS-MS and PO-MS, RP-MS respectively, and non-different between QV and QV-MS. In summary, soil nutrient properties are generally higher but vary among the slope positions in the silvopastoral treatments compared to pure forest treatments in the low hilly area. [ABSTRACT FROM AUTHOR]

The bioactive properties of underutilized corks such as Quercus cerris cork and planted Quercus suber cork in the Eastern Mediterranean are not well-known but are crucial in developing lignocellulosic biorefineries. To assess their biological potential, hydroethanolic cork extracts of Quercus cerris and Quercus suber were analyzed for phenolic composition, antioxidant, antiproliferative, antimicrobial activities, and hepatoxicity, as well as NO-production inhibition. Here, we show that a mild hydroethanolic extraction of Q. cerris and Q. suber corks yielded 3% phenolic extracts. The phenolic composition was similar in both cork extracts, with phenolic acids and ellagitannins as the primary compounds. The bioactivity of hydroethanolic cork extracts from Q. cerris surpassed that of Q. suber and showed effectiveness against all cancer cell lines tested. This first comprehensive study on the bioactivities of different corks involves detailed characterizations of phenolic compounds of cork extracts using UPLC-DAD-ESI/MSn, evaluations of the antioxidant properties with TBARS and OxHLIA methods, evaluation of antiproliferative activity against gastric (AGS), lung (NCI-H460), colon (CaCo2), and breast cancer (MCF7) cell lines, as well as evaluations of hepatotoxicity and NO-production inhibition. The findings from this study will help bolster the potential of using underutilized cork-rich barks as a valuable resource in bark-based biorefineries. [ABSTRACT FROM AUTHOR]

In Algeria, cork oak forests are of great socio-economic and ecological importance due to their great biological and ecosystemic diversity from east to west of the country. Given the decline of these forests and the difficulty of their natural regeneration, this work contributes to knowing some of the causes that affect this regeneration by studying the effect of the state of cork oak acorns (Quercus suber L.) on the emergence and growth of seedlings. The 917 cork oak acorns, collected from the township of Ain Lamcene in the Bissa forest, were divided into four batches according to their apparent condition: HeNPG (healthy non pre-germinated), HePG (healthy pre-germinated), HNPG (holed non pre-germinated) and HPG (holed pre-germinated) with respective rates of 36%, 30%, 21% and 13%. Analysis of the biometric parameters of the acorns reveals that the apparent state of health has no effect on the length and diameter of the acorns of the different batches; on the other hand, there is a difference in the weight. However, the difference is minimal and can be related to the consumption of the reserves of the cotyledons. The emergence of acorns was higher in healthy lots sown with a rate greater than 80%, compared to hose attacked by insects. The growth rhythm of cork oak plants was similar for the four batches of the sown acorns. In addition, seedlings from healthy acorns showed better development regarding height, number of leaves, and diameter at the collar and root growth than those from acorns attacked by insects. [ABSTRACT FROM AUTHOR]

The present study was conducted in monospecific stand of Cork oak (Quercus suber L.) in the Oulmes Central Plateau (Case of Zitchouene Forest), with the following objectives: determination of the organic carbon stock in the different compartments of the forest ecosystem, namely: the soil, the above-ground and below-ground biomass. To achieve these objectives, the biomass of the cork oak tree in the study area was researched using direct dry weight measurements on 30 sample trees. Furthermore, the volume of standing trees was estimated using a volume tariff based on direct measurements of circumference at 1.30 and total tree height, all of which allowed estimating the biomass expansion and conversion factor (BECF) specific to the Oulmes Central Plateau cork oak. As a result, the volume and above-ground biomass were estimated at 55.74 m3/ha and 20.13 t/ha of dry matter respectively. Soil organic carbon stock and biomass (above and below ground) were estimated at 43.02 t/ha and 16.60 t/ha, respectively. BECF, determined by the ratio between volume and biomass, was 0.59, which approaches the minimum value recorded under the same productivity conditions estimated by IPCC (0.6-1.4). [ABSTRACT FROM AUTHOR]

A progressive decline in tree growth may be induced by global warming, affecting tree health and eventually resulting in death, particularly for trees growing in rocky mountainous regions where seasonal droughts have become more pronounced. However, tree growth dynamics in areas experiencing pronounced climate change have received little attention. In this study, a total of 100 (10 m × 10 m) grid plots were investigated in planted forests of Chinese cork oak (Quercus variabilis Blume), which were established in the 1960s and 1970s in a rocky mountainous area near Beijing, northern China. Furthermore, the radial growth of Q. variabilis (a total of 843 trees sampled from the dominant [D], co-dominant [CD], and suppressed [S] crown classes) was analyzed using retrospective dendrochronology and generalized additive models. The effects of meteorological changes between 1962 and 2020 on radial growth across the three crown classes were examined using correlation analysis. The results indicated that the growth of Q. variabilis initially increased and then decreased after 2010 at the regional level, and these trends varied according to crown class. The radial growth of the D trees responded more positively to an increase in temperature and drought severity index (<0 for dry and >0 for wet conditions) compared with that of the CD and S trees. The growth of the D and CD trees continuously increased under higher temperatures during the rainy seasons (June to September); however, the increases were higher for D than for CD trees. In contrast, the radial growth of S trees declined. We confirmed the historical effects of rising temperatures on tree growth and health, which are linked to water availability. Our data suggested that Q. variabilis trees will be considerably affected by intensified droughts. This study furthers our knowledge regarding the impact of climate change on tree and forest growth and provides management strategies for afforestation projects in rocky mountainous areas that are facing climate change. [ABSTRACT FROM AUTHOR]

ABSTRACT Studies have reported the important role of soil properties in regulating insect herbivory under controlled conditions or at relatively large scales. However, whether fine‐scale variation of soil properties affects insect herbivory under natural conditions in forests is still unclear. We selected a ca. 300 ha Quercus variabilis forest area where the leaf damage was mainly caused by Lampronadata cristata (Lepidoptera: Notodontidae) and set 200 10 × 10 m plots within the area. We examined insect herbivory (percent leaf area damaged) on Q. variabilis and correlated it to soil properties and tree characteristics. Insect herbivory decreased with soil sand percentage and bulk density and increased with DBH and tree height. Effects of soil sand percentage and bulk density on insect herbivory were partly mediated by DBH and tree height. Our results indicated that soil physical properties may have significant effects on insect herbivory by directly influencing insect herbivores that need to complete their life cycle in the soil, or by indirectly affecting insect herbivores through influencing DBH and tree height which reflects the total leaf biomass available to the insect herbivore. This study may help to understand the complex relationship between soil and plant–insect interactions in forest ecosystems.

Abstract Background The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. In most trees, like holm oak, the first periderm is frequently replaced by subsequent internal periderms yielding a heterogeneous outer bark made of a mixture of periderms and phloem tissues, known as rhytidome. Exceptionally, cork oak forms a persistent or long-lived periderm which results in a homogeneous outer bark of thick phellem cell layers known as cork. Cork oak and holm oak distribution ranges overlap to a great extent, and they often share stands, where they can hybridize and produce offspring showing a rhytidome-type bark. Results Here we use the outer bark of cork oak, holm oak, and their natural hybrids to analyse the chemical composition, the anatomy and the transcriptome, and further understand the mechanisms underlying periderm development. We also include a unique natural hybrid individual corresponding to a backcross with cork oak that, interestingly, shows a cork-type bark. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach cork and rhytidome development, allowing an accurate identification of candidate genes and processes. The present study underscores that abiotic stress and cell death are enhanced in rhytidome-type barks whereas lipid metabolism and cell cycle are enriched in cork-type barks. Development-related DEGs showing the highest expression, highlight cell division, cell expansion, and cell differentiation as key processes leading to cork or rhytidome-type barks. Conclusion Transcriptome results, in agreement with anatomical and chemical analyses, show that rhytidome and cork-type barks are active in periderm development, and suberin and lignin deposition. Development and cell wall-related DEGs suggest that cell division and expansion are upregulated in cork-type barks whereas cell differentiation is enhanced in rhytidome-type barks.

The sustainability of forest species is directly related to the success of stand regeneration. Assuring success is particularly critical in stands where perpetuity relies on natural regeneration, as is often the case with cork oak forests. However, 59% of the stand in Portugal have no natural regeneration, and climate change could further worsen the sustainability of the system. The study summarizes the factors that affect the natural regeneration of cork oak (Quercus suber L.) based on current knowledge and presents a case study on a forest in Northeast Portugal, where the natural regeneration of Quercus suber under the effect of climate change have been monitored and analyzed. The present work focuses on the effect of stand density, i.e., tree cover, on the production of acorns, the establishment and survival of seedlings, and the impact of the summer season on seedling mortality. The monitoring was carried out in February, June, September 2022, and January 2023 in two stands with distinct stand canopy cover, when the region was under extreme drought. Data analysis was performed using the analysis of variance for repeated measures and the Mann–Whitney-Wilcoxon test. The study showed that cork oak regeneration is influenced by stand density, which promoted the establishment success and survival of natural regeneration in a period of reduced precipitation, despite possible competition for water resources. The mean number of seedlings differed significantly between the two stands. However, there were no significant differences in the mean number of seedlings throughout the field measurements. Additionally, the percentage of dead seedlings was low even after the summer season (9.5% of the total seedlings) in the denser stand. These results indicate that high canopy cover can have a protective effect for extreme climatic events and should be considered in forestry management to promote regeneration of the cork oak forests. [ABSTRACT FROM AUTHOR]

Background: The periderm is basic for land plants due to its protective role during radial growth, which is achieved by the polymers deposited in the cell walls. In most trees, like holm oak, the first periderm is frequently replaced by subsequent internal periderms yielding a heterogeneous outer bark made of a mixture of periderms and phloem tissues, known as rhytidome. Exceptionally, cork oak forms a persistent or long-lived periderm which results in a homogeneous outer bark of thick phellem cell layers known as cork. Cork oak and holm oak distribution ranges overlap to a great extent, and they often share stands, where they can hybridize and produce offspring showing a rhytidome-type bark. Results: Here we use the outer bark of cork oak, holm oak, and their natural hybrids to analyse the chemical composition, the anatomy and the transcriptome, and further understand the mechanisms underlying periderm development. We also include a unique natural hybrid individual corresponding to a backcross with cork oak that, interestingly, shows a cork-type bark. The inclusion of hybrid samples showing rhytidome-type and cork-type barks is valuable to approach cork and rhytidome development, allowing an accurate identification of candidate genes and processes. The present study underscores that abiotic stress and cell death are enhanced in rhytidome-type barks whereas lipid metabolism and cell cycle are enriched in cork-type barks. Development-related DEGs showing the highest expression, highlight cell division, cell expansion, and cell differentiation as key processes leading to cork or rhytidome-type barks. Conclusion: Transcriptome results, in agreement with anatomical and chemical analyses, show that rhytidome and cork-type barks are active in periderm development, and suberin and lignin deposition. Development and cell wall-related DEGs suggest that cell division and expansion are upregulated in cork-type barks whereas cell differentiation is enhanced in rhytidome-type barks. [ABSTRACT FROM AUTHOR]

Monitoring drought stress is crucial for estimating productivity and assessing the health status of forest ecosystems under global climate change. Solar-induced chlorophyll fluorescence (SIF) is mechanistically coupled to photosynthesis and has advantages over greenness-based vegetation indices in detecting drought. In recent years, SIF has commonly been used in monitoring drought stress in crop ecosystems. However, the response of tower-based SIF to drought stress in forest ecosystems remains unclear. In this study, we investigated the potential of tower-based SIF to monitor drought, which was quantified using the plant water stress index (PWSI) in a Chinese cork oak plantation. The results show the negative effect of drought on SIF, and afternoon depression of SIF emission under drought stress was observed. Canopy SIF (F) exhibited a nonlinear relationship with PWSI, while the quantum yield of SIF (ΦF) exhibited a significant linear relationship with PWSI at 687 nm and 760 nm (ΦF687: R2 = 0.90; ΦF760: R2 = 0.85). Incident radiation (PAR) and canopy structure affected the response of SIF to drought stress, with PAR as the main factor causing the nonlinear relationship between F and PWSI. Afternoon depression was described as the afternoon/morning ratio (AMR). AMRF and AMRΦF exhibited a negative linear response to PWSI. AMRF was less affected than F by PAR and canopy structures, and AMRΦF was more physiologically representative than ΦF. Moreover, AMRΦF was sensitive to VPD and REW, and it might be a good indicator of drought. Red SIF was more sensitive to drought than far-red SIF, as the R2 of PWSI with AMRΦF687 (R2 = 0.89) was higher than that with AMRΦF687 (R2 = 0.84). These results highlight the potential of tower-based SIF, especially red SIF, for drought monitoring in a plantation, and consideration of the physiological diurnal variation in SIF under drought stress is crucial for improving the accuracy of drought stress monitoring. [ABSTRACT FROM AUTHOR]

Background: The cork oak is the major forest element of northern Tunisia, especially in Kroumirie. It is a species of greatecological, economic and social value, with a natural distribution limited to the western Mediterranean basin. Following serious biotic and abiotic problems, oak forests have been greatly affected and their natural regeneration has become very difficult, even almost absent these last years marked by last climatic changes. The association of cork oak with autochthonous plant species such as leguminous is an original research to resolve this problem. As part of this reflection, the association of the cork oak with Cytisusvillosus could positively influence its growth and productivity by providing the nutrients necessary for its survival in the face of climatic constraints. Methods: The study was conducted in two sites in the Kroumirie (Ain Draham and El Feija forests). In each site two populations of the same bioclimatic stage are chosen: a population of only cork oak and a cork oak population associated with Cytisusvillosus. Several parameters were measured on trees at each population: morphological (height, circumference, leaf area index LMA) ecophysiological (photosynthesis, stomatal conductance, transpiration) and cork quality (porosity, humidity, quality) parameters. Result: The oaks with legumes in both Ain Drahem and Feija sites showed highly significant differences compared to the other two populations without association; for morphological and ecophysiological parameters. In the same way, statistical analysis has shown that the cork oak trees in Feija population with Cytisus have better cork quality than other populations. We can conclude that the cork oak behaves better and have higher growth and better cork quality in the presence of legumimous species like Cytisusvillosus. Such results could encourage the reintroduction of this legume especially in degraded areas of cork oaks for their maintenance and preservation especially in the current climate conditions. [ABSTRACT FROM AUTHOR]

The endemic Algerian Nuthatch Sitta ledanti, is classified as an endangered species by the IUCN and protected species by Algerian law. Available information on its nesting and breeding biology is sporadic and incomplete, the purpose of which is to provide additional data on the different aspects of multi-site nesting of the species. 22 nests are monitored across five forests, during the nesting season of 2021. An endoscopic camera was used to monitor eggs and nestlings in the nests during the whole study. Most of the nests (n = 20) were constructed in different parts of the dead trees such as trunks or branches of the Atlas cedar Cedrus atlantica, the Algerian oak Quercus canariensis, the African oak Quercus afares or Cork oak Quercus suber. The laying dates were from early April to the end of May when April 28 (± 13 days) is the laying season's median start date. The average clutch size was 4.6 (n = 21). The mean hatching success was 89.2%, while mean fledging success was 88.2%. The nestling sex ratio was 14 males versus 18 females. Data on clutch dates and fecundity of breeding pairs should be considered in any conservation approach and strategy in the context of habitat management and preservation. [ABSTRACT FROM AUTHOR]

The cork oak "Quercus suber L." is one of the most important forest trees in the world, especially in the Mediterranean Basin, due to its high environmental, socioeconomic, and landscape value throughout the year. In general, these trees face particular problems that affect their germination, growth, survival, and the other biotic and abiotic causes that affect natural regrowth. Thus, the most important of these problems is the annual irregularity in tree seed production. For this reason, The storage problems of this species are of concern to managers, who are using new alternative techniques to deal with the problem of the irregular annual production of oak seeds and to preserve them for as long as possible. The present work aimed to evaluate the effect of storing cork oak Quercus suber L. seeds at different temperatures and for different periods of up to 300 days on their vitality and ability to germinate. For this, the seeds were subjected to four storage parameters at four temperature levels: - 0.5°C, -1°C, +4°C with thermotherapy, and +4°C without thermotherapy as a control from January 2019 to September 2019. Analysis of the obtained results showed that the treatments studied significantly affected the measured parameters. After 30 and 60 days, the results of the 4 treatments concluded that the fourth storage treatment (storage of seeds directly at +4°C) presented a good performance in terms of the length of the seedlings, which was high (52.45 cm), the production of seedlings with an average diameter of 5.28 mm, and the important germination percentage (88.57%), unlike the other treatments. After a storage period of 270 days, the fourth storage treatment, the control, stored at 4°C without thermotherapy, still showed the best growth and development. This treatment also achieved a higher germination percentage (17.14%), plant height (11.33cm), and average diameter (1.85 mm) than the other treatments. [ABSTRACT FROM AUTHOR]

Acorns have been a vital food source for many communities worldwide, but there is limited research on their traditional uses and nutritional and medicinal properties. To address this gap, a study was conducted to explore the traditional methods of preparing and consuming acorns in Algeria and their potential benefits for human health. A questionnaire-based survey was conducted with a large sample of individuals from all over Algeria to collect data on their acquaintance with Quercus species, acorn consumption, consumption habits, and therapeutic uses of acorns. Results were subjected to a chi-square test and logistic regression statistical analysis to test the association between acorn consumption and the different sections under study. The survey found that 91% of participants consumed acorns, with sweet Holm and Cork oak being the most commonly consumed species. Acorn consumption was found to be influenced by gender, geographical position, familiarity with Quercus species, and belief that acorns are not exclusively animal food. The most common method of consumption was cooking, with roasting and boiling being the preferred cooking methods, and acorns were consumed seasonally, primarily during autumn. The study shows that acorn consumption in Algeria has the potential for economic benefits and can be a viable alternative to wheat flour. It also reveals the traditional gastronomic knowledge associated with acorn-based products and meals. The survey results highlight the diverse and significant knowledge of oak fruits by the local population and suggest that future research could enhance the practices and knowledge of acorn-based products and promote acorn consumption. [ABSTRACT FROM AUTHOR]

Agglomerated cork is a natural cork that has gone through a process of crushing and pressing using heat and binders. One of its applications is thermal insulator in construction. The design of these materials is becoming an essential part of building. The raw materials currently used to make insulators consume a large amount of energy, which has created the need to increase the use of renewable and ecological resources such as plant fibers to reduce the environmental problems generated. The objective of this study was to determine the different properties of experimental particleboard panels made from cork and Canary Island date palms without using any binder at minimum energy consumption. The produced cork–palm boards (density of 850 kg/m3, reached a MOR 8.83 N/mm2, MOE 794.5 N/mm2, and IB 0.38 N/mm2) are higher values than the traditional cork particleboards with UF made from cork. The thermal conductivity values obtained 0.069 to 0.096 W/m·K are higher than cork boards with UF. Ecological boards that can be used as rigid thermal insulators in the construction industry have been achieved to improve the mechanical properties of the traditional agglomerated cork. [ABSTRACT FROM AUTHOR]

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The effects of boiling water treatment on the physical properties of Quercus variabilis virgin cork (Qv VC) were examined and compared with those of Quercus suber reproduction cork (Qs RC). The water treatment was conducted at 100 °C for 1 h. Qv VC showed a significantly higher dimensional change in the three directions and lower weight loss than Qs RC by boiling water treatment. Untreated and boiled Qv VC showed higher density, air-dried moisture content, red/green (a*) and yellow/blue (b*) chromaticity, overall color change, shrinkage in all three directions, moisture adsorption on the entire surface, and swelling per 1% moisture content than untreated and boiled Qs RC. However, the lightness (L*) and water absorption on each surface were higher for Qs RC than for Qv VC. Moisture adsorption on each surface was comparable before and after heat treatment for both species. After boiling water treatment, the air-dried moisture content, dimensions, volume shrinkage, water absorption, and moisture adsorption on each surface and the entire surface increased, whereas L*, a*, b*, and swelling per 1% moisture content decreased. The results of the present study could be useful for further utilization of Qv cork growing in Korea. [ABSTRACT FROM AUTHOR]