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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]

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 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]

Biscogniauxia species are opportunistic pathogens primarily associated with Quercus species dieback in the Mediterranean basin. Among these species, Biscogniauxia mediterranea stands out as the only species previously documented in Tunisia, affecting Quercus suber and Erica multiflora. This study unveils a novel finding, reporting the presence of Biscogniauxia rosacearum on Strawberry trees in Tunisia. The identification of B. rosacearum isolates was confirmed based on DNA sequence data (ITS, TUB2 and ACT) and morphological traits. Artificial inoculation trials on leaves confirmed the pathogenicity of the fungus towards Arbutus unedo. This finding emphasizes the significance of implementing proactive measures to effectively combat this pathogen because of the polyphagous nature of Biscogniauxia species that raises concerns about its potential spread within vulnerable hosts in Tunisian oak forests. [ABSTRACT FROM AUTHOR]

Cork growth rings from three sites in the North West of Algeria were analysed in relation to monthly and annual precipitation and to climatic indices. Ring width and their growth indices were small, ranging from 2.03 mm(ZA), 2.43 mm(TA) and 2.06 mm (AM), corresponding to a thin cork. Thirteen-year time series were compared to precipitation data from 2009 to 2021. Ring width and growth indices revealed a strong correlation with annual rainfall (December to January) and spring rains (May to June). Phellogen activity also remains markedly influenced by the maximum temperatures of March. In the context of global climate change, the water balance of the study area is inadequate. The severe drought in the region was manifested by positive correlations with the index of De Martonne. This also seems valid for the two drought indices (Gaussen index and xerothermic index). The extension of the dry season beyond 6 months affects cork oak activity. [ABSTRACT FROM AUTHOR]

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]

Climate change is favouring the northward shift of Mediterranean oaks which are expanding their ranges at their leading edges. However, Mediterranean oaks have recalcitrant seeds (desiccation sensitive) that do not form seed banks, depending on climate conditions after seed fall and interactions between genetic determinants to germinate. Here we investigate the potential adaptation of Quercus suber range-wide populations to increasing spring temperature in germination timing and rates. We sowed 701 acorns from 9 populations from 10 mother trees each, at 15, 20 and 25 °C and monitored germination daily during 90 days. We modelled germination timing through Cox's proportional-hazards models, assessed populations' adaptation to spring temperature transfer distances and quantified the effect of acorn mass and storage duration on germination probability and timing with fixed-effects models. We used the mixed-effects models to predict germination climatic niches under current and RCP 8.5 2080 scenarios. Differences in germination timing were due to both the population origin and temperature treatment; germination rates showed a sub-optimality towards warmer-than-origin temperatures. The timing of germination decreased along with spring temperatures increment, with germination in 2080 predicted to occur 12 days earlier than to date in central Iberia. Warmer spring temperatures significantly accelerate the germination of recalcitrant Mediterranean species, which could alter seedlings' developmental environment and ultimately populations' regeneration and species composition. As such, germination timing should receive more attention from scientists and stakeholders and should be included in forest vulnerability assessments and assisted migration programs aiming at long-term forest regeneration to adapt forests to climate change. [ABSTRACT FROM AUTHOR]

Quercus suber is considered a sustainable tree mainly due to its outer layer (cork) capacity to regenerate after each harvesting cycle. Cork bark is explored for several application; however, its industrial transformation generates a significant amount of waste. Recently, cork by-products have been studied as a supplier of bioactive ingredients. This work aimed to explore whether near infrared spectroscopy (NIRS), a non-destructive analysis, can be employed as a screening device for selecting cork by-products with higher potential for bioactives extraction. A total of 29 samples of cork extracts were analysed regarding their qualitative composition. Partial least squares (PLS) models were developed for quantification purposes, and R2P and RER values of 0.65 and above 4, respectively, were obtained. Discrimination models, performed through PLS-DA, yielded around 80% correct predictions, revealing that four out of five of samples were correctly discriminated, thus revealing that NIR can be successfully applied for screening purposes. [ABSTRACT FROM AUTHOR]

Suberin, a complex biopolymer, forms a water- and gas-insoluble barrier that protects the inner tissues of plants. It is abundant in tree bark, particularly in the cork oak Quercus suber. Anatomically, fossil bark has been described since the Devonian. However, its distinctive constituent suberin has not yet been reported from the fossil record. Here we present unambiguous chemical evidence for intact suberin from the bark of a middle Eocene monkeyhair tree from Geiseltal, eastern Germany. High-performance liquid chromatography coupled to electrospray ionization mass spectrometry (HPLC–ESI-MS) detected constituents of suberin in the outer layer the fossil monkeyhair tree, which confirms previous morphological interpretation of this tissue as bark, and chemically differentiates this layer from the two tissues of the inner layer. Notably, this is the first study with compelling chemical evidence for suberin in fossil bark. Fluorescence microspectroscopy additionally supports the presence of suberin. Fossilization conditions in the Eocene Geiseltal deposit were likely mild, with low moisture and temperatures, contributing to the remarkable preservation of bark and inner laticifer mats of the monkeyhair trees growing there 45 million years ago. [ABSTRACT FROM AUTHOR]

The crystalline characteristics, chemical composition, and thermal decomposition of elements in Quercus variabilis (Qv) virgin cork were investigated using X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric methods, respectively, and compared with those of elements in Quercus suber (Qs) reproduction cork. Samples of cork elements, including pure cork, lenticular filling tissue (LFT), dark-brown zone (DBZ), and sclereids, were prepared. The X-ray diffractograms of pure cork from both species showed an amorphous pattern, whereas those of LFT, DBZ, and sclereid showed a crystalline cellulose I pattern. The relative crystallinity of DBZ was significantly lower than that of Qv LFT and the sclereid. In the FTIR spectra, Qv pure cork tended to show weaker band intensities for the suberin, lignin, and carbohydrate compounds than Qs pure cork. The pure corks of both species showed stronger suberin bands than LFT, DBZ, and the sclereid. In the thermogravimetric analyses, the peaks of hemicellulose and cellulose decomposition in both pure corks were weaker than those in LFT, DBZ, and sclereid, whereas the peaks of suberin decomposition in both pure corks were the highest among all elements. [ABSTRACT FROM AUTHOR]

Somatic embryogenesis (SE) is a crucial biotechnological tool for large‐scale mass propagation of selected material, genetic transformation and breeding, with many advantages for forest tree improvement. However, the application of SE in forest species is limited because of their recalcitrance. SE is also a valuable system for studying cell reprogramming, acquisition of totipotency and embryo development. Increasing evidence reveals that epigenetic reprogramming takes place during SE through DNA methylation, although there is scarce information on forest species. In this work, we have evaluated DNA methylation dynamics during SE and the effects of the DNA demethylating agent 5‐azacytidine (AzaC) in cork oak. After induction and early stages of SE, a reduced DNA methylation level is observed, followed by an increase of methylation during embryo differentiation. These changes in DNA methylation during SE progression were associated with expression profiles of DNA methyltransferase genes QsMET1, QsDRM2 and QsCMT3, and DNA demethylase QsDME‐like. Treatment with AzaC reduced DNA methylation, promoted SE induction rate and proembryogenic masses proliferation, and induced the expression of the SE marker gene QsSERK1‐like. However, continuous AzaC treatment hindered embryo differentiation, suggesting that DNA methylation is needed for further embryo development. Interestingly, AzaC removal from the culture medium of embryogenic masses restored embryo development and led to a significant increase in somatic embryo production compared with untreated cultures. These findings open new possibilities using transitory treatments with small molecule epigenetic modulators, as AzaC, to enhance SE yields for forestry breeding programs. [ABSTRACT FROM AUTHOR]

Chloroplast genome diversity in cork oak (Quercus suber) is characterised by the occurrence of haplotypes that are akin to those found in other Mediterranean oak species, particularly in Q. ilex and Q. rotundifolia, suggesting the possible presence of an introgressed chloroplast lineage. To further investigate this pattern, we reconstructed chloroplast haplotypes by sequencing four chloroplast markers (cpDNA), sampled across 181 individuals and 10 taxa. Our analyses resulted in the identification of two diversified chloroplast haplogroups in Q. suber, corresponding to a geographically widespread lineage and an Afro-Iberian lineage. Time-calibrated phylogenetic analyses of cpDNA point to a Miocene origin of the two haplogroups in Q. suber, suggesting that the Afro-Iberian lineage was present in cork oak before the onset of glaciation periods. The persistence of the two haplogroups in the western part of the species distribution range may be a consequence of either ancient introgression events or chloroplast lineage sorting, combined with different fixation in refugia through glaciation periods. Our results provide a comprehensive insight on the origins of chloroplast diversity in these ecologically and economically important Mediterranean oaks. [ABSTRACT FROM AUTHOR]

The great extension of forests in the Djebel El Ghorra massif of El Kala National Park (north‐eastern Algeria) allowed us to recognise three distinct forest formations: cork oak stands (Quercus suber), zeen oak stands (Quercus canariensis) and mixed oak (Quercus suber and Quercus canariensis) forest. Their peculiarities showed ideal ecological characteristics for the colonisation of corticolous lichens the two phorophytes. The three forest formations were sampled between 2017 and 2022. The identification of the taxa is based on stereo‐microscopic examinations and usual chemical tests. Systematic surveys were conductedand allowed us to establish a list of 141 lichen taxa divided into 30 families. [ABSTRACT FROM AUTHOR]

The periodic exploitation of the cork coinciding with the wildfire reinforces the vulnerability of the trees by affecting their vigour and their productive potential. Results showed that trees lightly affected by fire (recoverable) manage to overcome the disturbance without major impact on regeneration and growth variables (IR = 3.80, growth = 2.04mm/year; thickness = 14.81mm; volumetric density = 283,59 kg/m3; IQ = 8,56). Paradoxically, standing dead trees record a very low resilience (IR = 1.23; growth = 0.26mm/year; thickness = 1.99mm; volumetric density = 347.02 kg/m3 and IQ = 1.50). [ABSTRACT FROM AUTHOR]

The challenges of this work focus on better understanding combustion characteristics and their importance to fire hazard by performing thermogravimetric analysis (TGA). The ultimate goal is to provide a methodology for determining the most relevant indices for a robust fire hazard classification of the species. One of the principles of this methodology is the use of a linear regression method for determining the indices and the activation energy. To achieve this scope, chemical, thermal and kinetic analysis will be performed. Nine combustion indices were calculated and compared to assess combustion characteristics such as ignition, combustion and burnout. Experiments were carried out at three heating rates of 10, 15 and 20 °C min−1 under air atmosphere. A selection of forest materials frequently devastated by wildfire, i.e., Quercus pubescens (QP), Quercus suber (QS), Olea europaea (OE) and Genista Salzmannii needles (GSN), were studied. The TG-DTG curves have shown that the combustion process consists of two stages: devolatilization and char oxidation. The whole process was controlled by the release of volatile gases. According to the relative linearized (RL) index of spontaneous ignition, the samples were ordered as follows: OE > GSN ≥ QS > QP. OE appears to be the most reactive and prone to spontaneous ignition compared to the other samples. The same order was achieved for the combustion characteristic index and, approximately, for the integrated flammability. On the other hand, the average Ea at the low temperature stage of the combustion process was low for GSN (147 ± 9 kJ mol−1) and OE (159 ± 4 kJ mol−1) and high for QP (179 ± 14 kJ mol−1) and QS (174 ± 3 kJ mol−1). Finally, this work provides valuable insight into the relationship between chemical properties and combustion indices and the components that make some indices more effective than others. [ABSTRACT FROM AUTHOR]

Over the last decade, genome-scale metabolic models have been increasingly used to study plant metabolic behaviour at the tissue and multi-tissue level under different environmental conditions. Quercus suber, also known as the cork oak tree, is one of the most important forest communities of the Mediterranean/Iberian region. In this work, we present the genome-scale metabolic model of the Q. suber (iEC7871). The metabolic model comprises 7871 genes, 6231 reactions, and 6481 metabolites across eight compartments. Transcriptomics data was integrated into the model to obtain tissue-specific models for the leaf, inner bark, and phellogen, with specific biomass compositions. The tissue-specific models were merged into a diel multi-tissue metabolic model to predict interactions among the three tissues at the light and dark phases. The metabolic models were also used to analyse the pathways associated with the synthesis of suberin monomers, namely the acyl-lipids, phenylpropanoids, isoprenoids, and flavonoids production. The models developed in this work provide a systematic overview of the metabolism of Q. suber, including its secondary metabolism pathways and cork formation. Author summary: Our study presents a comprehensive metabolic model of Quercus suber, also known as the cork oak tree, which is a keystone species of the Mediterranean forests. We used a genome-scale approach to build a model (iEC7871) that integrates transcriptomics data and accounts for the metabolic interactions among different tissues of the tree. Specifically, we derived tissue-specific models for the leaf, inner bark, and phellogen, which are the main tissues involved in cork production. We then combined these models into a diel multi-tissue model that simulates the metabolic behaviour of the tree under light and dark conditions. Our model includes the pathways associated with the biosynthesis of suberin monomers, which are the main components of cork. By analysing these pathways, we identified potential targets for improving cork quality and yield in Q. suber. Our work provides a valuable resource for studying the metabolism of cork oak trees and highlights the importance of integrating multi-omics data to build predictive models of plant metabolism. [ABSTRACT FROM AUTHOR]

We report the discovery of Cotula australis Hook.f. for the first time in Morocco and North Africa. We found it living in the cork-oak forest of Maamora (Northwest). This species, a member of the family Asteraceae, is introduced to Morocco and has potential to be highly invasive and destructive to the native environment. We describe the distinctive taxonomic and morphological characters of this species and provide notes on its distribution, ecology, and habitat. [ABSTRACT FROM AUTHOR]

Diplodia corticola is one of the most aggressive fungal pathogens of Quercus species involved in the decline of Mediterranean oak forests. In this study, three strains of D. corticola associated with holm (Quercus ilex) and cork (Quercus suber) oak trees exhibiting dieback symptoms and cankers in Algeria were selected to investigate the production of secondary metabolites. Metabolomic analyses revealed the production of several known compounds, such as sphaeropsidins, diplopyrones and diplofuranones. Moreover, the comparative investigation of secondary metabolites produced by the analyzed strains with different degrees of virulence revealed possible implications of these compounds in the fungal virulence. In particular, sphaeropsidins seem to be the main phytotoxic compounds of D. corticola involved in the infections of Quercus species, with a possible synergistic influence of the less representative compounds in the fungal virulence. [ABSTRACT FROM AUTHOR]

The biocatalysis of β-myrcene into value-added compounds, with enhanced organoleptic/therapeutic properties, may be performed by resorting to specialized enzymatic machinery of β-myrcene-biotransforming bacteria. Few β-myrcene-biotransforming bacteria have been studied, limiting the diversity of genetic modules/catabolic pathways available for biotechnological research. In our model Pseudomonas sp. strain M1, the β-myrcene catabolic core-code was identified in a 28-kb genomic island (GI). The lack of close homologs of this β-myrcene-associated genetic code prompted a bioprospection of cork oak and eucalyptus rhizospheres, from 4 geographic locations in Portugal, to evaluate the environmental diversity and dissemination of the β-myrcene-biotransforming genetic trait (Myr+). Soil microbiomes were enriched in β-myrcene-supplemented cultures, from which β-myrcene-biotransforming bacteria were isolated, belonging to Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, and Sphingobacteriia classes. From a panel of representative Myr+ isolates that included 7 bacterial genera, the production of β-myrcene derivatives previously reported in strain M1 was detected in Pseudomonas spp., Cupriavidus sp., Sphingobacterium sp., and Variovorax sp. A comparative genomics analysis against the genome of strain M1 found the M1-GI code in 11 new Pseudomonas genomes. Full nucleotide conservation of the β-myrcene core-code was observed throughout a 76-kb locus in strain M1 and all 11 Pseudomonas spp., resembling the structure of an integrative and conjugative element (ICE), despite being isolated from different niches. Furthermore, the characterization of isolates not harboring the Myr+-related 76-kb locus suggested that they may biotransform β-myrcene via alternative catabolic loci, being thereby a novel source of enzymes and biomolecule catalogue for biotechnological exploitation. Key points: • The isolation of 150 Myr+bacteria hints the ubiquity of such trait in the rhizosphere. • The Myr+trait is spread across different bacterial taxonomic classes. • The core-code for the Myr+trait was detected in a novel ICE, only found in Pseudomonas spp. [ABSTRACT FROM AUTHOR]

With the development of spectrum observation technology, solar-induced chlorophyll fluorescence (SIF)—an effective substitute for photosynthesis—has been widely used to monitor crop stress, vegetation phenology and ecosystem productivity. The relationship between fluorescence and photosynthesis is complicated because they are sensitive to environmental changes. Understanding the response of SIF to environmental factors is of great significance for clarifying the variation dynamic and relationship between SIF and photosynthesis under different conditions. In this study, the canopy SIF and the environmental factors of a Quercus variabilis BI. plantation were observed simultaneously, and the response of SIF to environmental factors at a daily scale and at a half-hour scale was analyzed. The results showed that SIF had obvious seasonal and diurnal dynamics and was mainly driven by photosynthetically active radiation (PAR). The influence of PAR, air temperature (Ta), vapor pressure deficit (VPD), soil moisture (SM) and wind speed (Ws) on SIF varied with the lapse of the growing season. After eliminating the covariant effect of PAR on the Ta and VPD during the whole growing season, the relationship between VPD and SIF was found to be negative, and the effect of Ta on SIF disappeared. This study enriched the ground observation dataset and provided support for understanding the variations in the relationship between SIF and photosynthesis under different conditions. [ABSTRACT FROM AUTHOR]

Anthracological analyses of charcoal samples retrieved from Pit 16 of Perdigões (Reguengos de Monsaraz, Portugal), a secondary deposition of cremated human remains dated back to the middle of the 3rd millennium BC, enabled the identification of 7 different taxa: Olea europaea, Quercus spp. (evergreen), Pinus pinaster, Fraxinus cf. angustifolia, Arbutus unedo, Cistus sp. and Fabaceae. All taxa are characteristic of both deciduous and evergreen Mediterranean vegetation, and this data might indicate that the gathering of woods employed for the human cremation/s occurred either on site, or in its vicinity. However, considering both the large distribution of the identified taxa and data about human mobility, it is not possible to conclusively determine the origin of the wood used in the cremation(s). Chemometric analysis were carried out to estimate the absolute burning temperature of woods employed for the human cremation/s. An in-lab charcoal reference collection was created by burning sound wood samples of the three main taxa identified from Pit 16, Olea europaea var. sylvestris, Quercus suber (evergreen type) and Pinus pinaster, at temperatures between 350 and 600 °C. The archaeological charcoal samples and the charcoal reference collection were chemically characterized by using mid-infrared (MIR) spectroscopy in the 1800–400 cm-1 range, and Partial Least Squares (PLS) regression method was used to build calibration models to predict the absolute combustion temperature of the archaeological woods. Results showed successful PLS forecasting of burn temperature for each taxon (significant (P <0.05) cross validation coefficients). The anthracological and chemometric analysis evidenced differences between the taxa coming from the two stratigraphic units within the Pit, SUs 72 and 74, suggesting that they may come from two different pyres or two different depositional moments. [ABSTRACT FROM AUTHOR]

The present study aims to characterize the floristic diversity and the demographic structure of the woody groups of cork oak (Quercus suber L.) of the forest of Ouled Bechih (Souk Ahras). Floristic and dendrometric data were collected in four plots of 900 m² and regeneration was assessed. The flora inventory has identified 25 species belonging to 25 genera and 18 families. The Asteraceae family is the most common (20%), followed by the Fabaceae, Oleaceae and Rosaceae (8%). The other families include species that are very poorly represented (4%). The diameter and height structures show a concentration of adult individuals in all the stands. In the perspective of rehabilitation and sustainable management of forest ecosystems, this study provides additional information on the current state of cork oak stands in the Ouled Bechih forest. [ABSTRACT FROM AUTHOR]

This study aims to assess the current state of health of the cork oak (Quercus suber) and its evolution in the forest of Zouagha (Mila). For this, eight plots were chosen at random. The dendrometric parameters measured are the diameter at 1.3 m above the ground and the total height of the trees, thus morphological observations were made on the aerial part of the same samples and analyzed by the tree architecture method (ARCHI). The average density of cork oak in this forest is 157±24 individual/ha with an average basal area of 27.09 ± 8.53 m²/ha. The diagnostic results show that the majority of trees in these plots are currently in classes of the ARCHI R type with a rate of 51.1%; comes in second position the ARCHI Healthy type with a percentage of 39.2; and the ARCHI S type records a low rate (7.3%). The ARCHI D and ARCHI I types are almost absent. The sanitary condition of these plots is quite good, despite the negligible presence of standing dead trees. [ABSTRACT FROM AUTHOR]

In this study, an analysis of the influence of extractives, suberin and lignocellulosic components on the pyrolysis decomposition and fire reaction mechanisms of a cork oak powder from Quercus suber L. is presented. The summative chemical composition of cork powder was determined. Suberin was the main component at 40% of the total weight, followed by 24% of lignin, 19% of polysaccharides and 14% of extractives. The absorbance peaks of cork and its individual components were further analyzed by means of ATR-FTIR spectrometry. Thermogravimetric analysis (TGA) showed that the removal of extractives from cork slightly increased the thermal stability between 200 °C and 300 °C and led to the formation of a more thermally stable residue at the end of the cork decomposition. Moreover, by removing suberin, a shift of the onset decomposition temperature to a lower temperature was noticed, indicating that suberin plays a major role in enhancing the thermal stability of cork. Furthermore, non-polar extractives showed the highest flammability with a peak of heat release rate (pHRR) of 365 W/g analyzed by means of micro-scale combustion calorimetry (MCC). Above 300 °C, the heat release rate (HRR) of suberin was lower than that of polysaccharides or lignin. However, below that temperature it released more flammable gases with a pHRR of 180 W/g, without significant charring ability, contrary to the mentioned components that showed lower HRR due to their prominent condensed mode of action that slowed down the mass and heat transfer processes during the combustion process. [ABSTRACT FROM AUTHOR]

One of the most determining factors in forest fire behaviour is to characterize forest fuel attributes. We investigated a complex Mediterranean forest type—mountainous Abies pinsapo–Pinus–Quercus–Juniperus with distinct structures, such as broadleaf and needleleaf forests—to integrate field data, low density Airborne Laser Scanning (ALS), and multispectral satellite data for estimating forest fuel attributes. The three-step procedure consisted of: (i) estimating three key forest fuel attributes (biomass, structural complexity and hygroscopicity), (ii) proposing a synthetic index that encompasses the three attributes to quantify the potential capacity for fire propagation, and (iii) generating a cartograph of potential propagation capacity. Our main findings showed that Biomass–ALS calibration models performed well for Abies pinsapo (R2 = 0.69), Juniperus spp. (R2 = 0.70), Pinus halepensis (R2 = 0.59), Pinus spp. mixed (R2 = 0.80), and Pinus spp.–Juniperus spp. (R2 = 0.59) forests. The highest values of biomass were obtained for Pinus halepensis forests (190.43 Mg ha−1). The structural complexity of forest fuels was assessed by calculating the LiDAR Height Diversity Index (LHDI) with regard to the distribution and vertical diversity of the vegetation with the highest values of LHDI, which corresponded to Pinus spp.–evergreen (2.56), Quercus suber (2.54), and Pinus mixed (2.49) forests, with the minimum being obtained for Juniperus (1.37) and shrubs (1.11). High values of the Fuel Desiccation Index (IDM) were obtained for those areas dominated by shrubs (−396.71). Potential Behaviour Biomass Index (ICB) values were high or very high for 11.86% of the area and low or very low for 77.07%. The Potential Behaviour Structural Complexity Index (ICE) was high or very high for 37.23% of the area, and low or very low for 46.35%, and the Potential Behaviour Fuel Desiccation Index (ICD) was opposite to the ICB and ICE, with high or very high values for areas with low biomass and low structural complexity. Potential Fire Behaviour Index (ICP) values were high or very high for 38.25% of the area, and low or very low values for 45.96%. High or very high values of ICP were related to Pinus halepensis and Pinus pinaster forests. Remote sensing has been applied to improve fuel attribute characterisation and cartography, highlighting the utility of integrating multispectral and ALS data to estimate those attributes that are more closely related to the spatial organisation of vegetation. [ABSTRACT FROM AUTHOR]

The growing threat of climatic crisis and fossil fuel extinction has caused a boom in sustainability trends. Consumer demand for so-called eco-friendly products has been steadily increasing, built upon the foundation of environmental protection and safeguarding for future generations. A natural product that has been used for centuries is cork, resulting from the outer bark of Quercus suber L. Currently, its major application is the production of cork stoppers for the wine industry, a process that, although considered sustainable, generates by-products in the form of cork powder, cork granulates, or waste such as black condensate, among others. These residues possess constituents of interest for the cosmetic and pharmaceutical industries, as they exhibit relevant bioactivities, such as anti-inflammatory, antimicrobial, and antioxidant. This interesting potential brings forth the need to develop methods for their extraction, isolation, identification, and quantification. The aim of this work is to describe the potential of cork by-products for the cosmetic and pharmaceutical industry and to assemble the available extraction, isolation, and analytical methods applied to cork by-products, as well the biological assays. To our knowledge, this compilation has never been done, and it opens new avenues for the development of new applications for cork by-products. [ABSTRACT FROM AUTHOR]

Background and Aims Cork oaks (Quercus section Cerris) comprise 15 extant species in Eurasia. Despite being a small clade, they display a range of leaf morphologies comparable to the largest sections (>100 spp.) in Quercus. Their fossil record extends back to the Eocene. Here, we explore how cork oaks achieved their modern ranges and how legacy effects might explain niche evolution in modern species of section Cerris and its sister section Ilex , the holly oaks. Methods We inferred a dated phylogeny for cork and holly oaks using a reduced-representation next-generation sequencing method, restriction site-associated DNA sequencing (RAD-seq), and used D- statistics to investigate gene flow hypotheses. We estimated divergence times using a fossilized birth–death model calibrated with 47 fossils. We used Köppen profiles, selected bioclimatic parameters and forest biomes occupied by modern species to infer ancestral climatic and biotic niches. Key Results East Asian and Western Eurasian cork oaks diverged initially in the Eocene. Subsequently, four Western Eurasian lineages (subsections) differentiated during the Oligocene and Miocene. Evolution of leaf size, form and texture was correlated, in part, with multiple transitions from ancestral humid temperate climates to mediterranean, arid and continental climates. Distantly related but ecologically similar species converged on similar leaf traits in the process. Conclusions Originating in temperate (frost-free) biomes, Eocene to Oligocene ranges of the primarily deciduous cork oaks were restricted to higher latitudes (Siberia to north of Paratethys). Members of the evergreen holly oaks (section Ilex) also originated in temperate biomes but migrated southwards and south-westwards into then-(sub)tropical southern China and south-eastern Tibet during the Eocene, then westwards along existing pre-Himalayan mountain ranges. Divergent biogeographical histories and deep-time phylogenetic legacies (in cold and drought tolerance, nutrient storage and fire resistance) thus account for the modern species mosaic of Western Eurasian oak communities, which are composed of oaks belonging to four sections. [ABSTRACT FROM AUTHOR]

Light use efficiency (LUE) is a key parameter connecting light absorption and carbon fixation and understanding the relationship between fluorescence and photosynthesis. Based on the absorbed energy dissipation pathways, LUE can be divided into light use efficiency of photosynthetic (LUEp) and light use efficiency of fluorescence (LUEf). The relationship between LUEp and LUEf of poplar and cork oak and the differences between species were explored in this study, to better understand the mechanism links between solar-induced chlorophyll fluorescence (SIF) and gross primary productivity (GPP) in deciduous broadleaf forests. In this study, the poplar (Populus alba x Populus gllandulosa) and cork oak (Quercus variabilis BI.) seedlings were used as the objects to measure the divergences in SIF and net photosynthetic rate (Pn) under the same soil moisture and nutrient conditions, to explore the responses of LUEp/LUEf to photosynthetically active radiation (PAR). The results showed that, (1) SIF was driven by incident PAR, SIF and PAR were significantly positively correlated. The coefficient of determination (R²) of poplar and cork oak were 0.965 and 0.973, respectively, and LUEf was higher in poplar. Pn gradually increased with increasing PAR. The light saturation point (LSP) of poplar was significantly higher than that of cork oak, which were 998.59 and 674 μmolCO2·m-2·s-1, respectively. (2) Pn first increased with the increasing SIF, and then the Pn of poplar was gradually saturated, while that of cork oak continued to slowly increase. (3) LUEp and LUEf showed significant negative linear correlation, and LUEp/LUEf decreased exponentially with increasing PAR, there was no significant difference in the change pattern and amplitude between tree species. During the daytime, with the increase of PAR, LUEf changed slightly, while LUEp decreased significantly, and the proportion of light energy allocation to carbon assimilation decreased. Therefore, Pn saturated under high light intensity, SIF and GPP showed exponential correlation in intraday scale, and the exponential relationship was consistent across tree species. [ABSTRACT FROM AUTHOR]

This article is a Commentary on Li et al. (2024), 242: 2237–2250. [ABSTRACT FROM AUTHOR]

Cork oak landscapes are fascinating ecosystems, historically managed for cork extraction. The persistence in this habitat of many hollow veteran trees provides suitable micro‐habitats for saproxylic beetles.We investigated the saproxylic beetle community of two isolated cork oak woodlands of central Italy with different degree of recovery after human transformation: (1) an open woodland and (2) a dense mixed woodland, both dominated by cork oak trees.We found endemic, rare and threatened saproxylic beetles in both the areas, confirming the important conservation value of cork oak landscapes. In the open woodland we observed a higher number of species in all trophic categories, except for mycophagous specialists. Several microhabitat variables reflected the different stage of recovery of the two woodlands.Our findings suggest the crucial role of diversified environments in protected areas: even a small difference in the degree of recovery (i.e., tree closeness) can affect the number of beetle species. Specifically, we found (1) more xerophilous species in the open woodland and (2) more mesophilous species in the dense mixed woodland. [ABSTRACT FROM AUTHOR]

Cork quality indices were characterised in eight cork oak stands in the production region of Oranie (North-West, Algeria), based on field sampling of 75 trees/stand. The superposition of the quality indices provided by the Coveless CQ05™ onto the measurements of the technological cork features carried out in the laboratory showed a perfect homogenisation between the two processes. The best classes of quality indices (QI-A (19.5, 19, 12.75, 12)) include thickness (26.90 mm), annual growth (2.11 mm.year−1), the volumetric density (198.94 kg.m−3) and the porosity coefficient (2.65%). Regarding the poor quality indices classes (IQ-C (1.5), these averages tend to increase so as to reduce the market value of cork, in particular the density (355.11 kg.m−3), porosity (7.50%) and defects (70% for earthy cork and 30% for inclusions) The results showed the preponderant role of quality indices in the good marketing of cork and the classification of production areas. [ABSTRACT FROM AUTHOR]

This study aimed to review the requirements and difficulties of natural and artificial regeneration of cork oak (Quercus suber L.) in the Mediterranean Basin. Cork oak regeneration is achieved naturally by means of sexual or vegetative reproduction (by seeds or by sprouting), or artificially through direct seeding, or seedling planting. Both natural and artificial regeneration of cork oak frequently encounter numerous difficulties which limit the ecological conditions for cork oak regeneration, including acorn predation, slow growth, vegetative competition, browsing of seedlings, fires, pests and diseases, and summer drought. We reviewed the state of the art of these difficulties and summarize the potential solutions for each regeneration form. [ABSTRACT FROM AUTHOR]

Cork smoker wash solids (black wax) that is obtained in the process of making corkboard by treating the ground cork with superheated steam is useless waste, generating environmental problems. On the other hand, black wax is a rich source of friedelin (1) and 3-hydroxyfriedel-3-en-2-one (3), pentacyclic triterpenoids belonging to the friedelane family. In the present work, a simple, fast, and efficient procedure for the extraction of highly purified friedelin and 3-hydroxyfriedel-3-en-2-one from black wax is presented. Extraction of black wax with hexane or acetone afforded a mixture of friedelin and 3-hydroxyfriedel-3-en-2-one. However, chromatographic separation of 1 and 3, due to their very similar Rf coefficients, is difficult, especially on a multigram scale. Therefore, the conversion of 3-hydroxyfriedel-3-en-2-one to an acetyl derivative 4 was proposed by acetylation of the above mixture. Appropriate selection of the eluent sequence allows for rapid and efficient separation of the resulting mixture of 1 and 4. [ABSTRACT FROM AUTHOR]

New records of alien plants escaped from cultivation in Algeria. — In this contribution are reported three vascular species new to the alien flora of Algeria and continental North Africa, reported outside the cultures in the Skikda region (northeastern Algeria). Duranta erecta and Justicia adhatoda are considered casual, Tecomaria capensis is considered naturalized. The latter is established in a relic of a maquis of Quercus suber and shows a significant potential for more spreading. Thus, T. capensis should be monitored to prevent a prompt potential invasiveness in Algeria. [ABSTRACT FROM AUTHOR]

New information on the diversity of lichen flora of the Edough Peninsula in Algeria is presented and analysed. This study aimed to estimate the diversity of corticolous lichens on the rhytidome of Quercus suber L. in the district of Seraïdi, Annaba town, which is situated in north-eastern Algeria. During this study, nineteen species new to the Edough Peninsula were identified. Two species of the Pannariaceae family, Pectenia plumbea (Lightf.) P.M. Jørg, L. Lindblom, Wedin & S. Ekman and Fuscopannaria leucosticta (Tuck.) P.M. Jørg., are rare in the region. Pectenia plumbea is a new species to the region, whereas Fuscopannaria leucosticta is new to the region and, after a long time, was rediscovered in Algeria. [ABSTRACT FROM AUTHOR]

To provide information on the identification and quality evaluation of Q. variabilis virgin cork from Korea, the qualitative anatomical characteristics of the virgin cork were observed by optical and scanning electron microscopy and compared with those of Q. suber reproduction cork from Portugal. Q. variabilis showed a narrower growth ring than Q. suber. A dark-brown zone with sclereids was found only in Q. variabilis cork. The lenticular channel in Q. variabilis is larger than that in Q. suber. Q. variabilis virgin cork showed a distinct growth ring boundary and an abrupt transition from earlycork to latecork with a few rows of latecork cells. Q. suber reproduction cork showed an indistinct growth ring with a gradual transition from one to two rows of latecork cells. In the earlycork, Q. suber showed mild corrugation, while Q. variabilis displayed significant corrugation with collapsed and distorted cork cells. The lenticular channel in Q. variabilis virgin cork was surrounded by thick-walled cells filled with compact lenticular filling tissue. Q. suber reproduction cork had an opening with loose lenticular filling tissue surrounded by thick-walled cells. Prismatic crystals, thick-walled sclereid cells, and fiber-sclereids were found only in Q. variabilis. A few trabeculae were found in both cork samples. [ABSTRACT FROM AUTHOR]

Cork is a versatile natural material. It can be used as an insulator in construction, among many other applications. For good forest management of cork oaks, forest owners need to calculate the volume of cork periodically. This will allow them to choose the right time to harvest the cork. The traditional method is laborious and time consuming. The present work aims to automate the process of calculating the trunk area of a cork oak from which cork is extracted. Through this calculation, it will be possible to estimate the volume of cork produced before the stripping process. A deep neural network, Mask R-CNN, and a machine learning algorithm are used. A dataset of images of cork oaks was created, where targets of known dimensions were fixed on the trunks. The Mask R-CNN was trained to recognize targets cork regions, and so the area of cork was estimated based on the target dimensions. Preliminary results show that the model presents a good performance in the recognition of targets and trunks, registering a mAP@0.7 of 0.96. After obtaining the mask results, three machine learning models were trained to estimate the cork volume based on the area and biometric parameters of the tree. The results showed that a support vector machine produced an average error of 8.75%, which is within the error margins obtained using traditional methods. [ABSTRACT FROM AUTHOR]

In this paper we reported the list of nocturnal macromoth collected during one year of sampling in a territory delimited by Alli and Simeri rivers, on the south-eastern slope of the Sila Massif, Calabria. Ten sites representative of the main forest types, mainly thermophilous oaks and riparian forests, were investigated at an altitude between 90 and 650 m a.s.l. One UV LED light trap was positioned in each site, activated monthly during the same night, from June 2019 to April 2021. Altogether we collected 20,366 specimens belonging to 429 species. Most abundant species were those linked to the forest cover by the feeding habit of larvae (Eupithecia dodoneata, Cyclophora puppillaria, Watsonalla uncinula, and Catocala sp.pl.) or those without strict ecological preferences (Peribatodes rhomboidaria, Idaea filicata, I. degeneraria, Eilema caniola). The finding of the following species has great biogeographical interest: Cryphia receptricula, found for the first time in Calabria, Aegle agatha, known in Italy for three localities so far, Horisme exoletata, so far reported in peninsular Italy in this area only, Denticucullus pygmina and Orectis cfr. proboscidata, so far collected in Calabria in only one locality. Furthermore, 44 species were collected for the first time in the Sila Massif and 7 for the first time along the Ionian Coast. [ABSTRACT FROM AUTHOR]

Wood-boring insects are considered potential contributing/inciting factors to oak decline. Cerambyx cerdo (Cc) and C. welensii (Cw) are two sympatric oak-living large sapro-xylophagous longhorn beetles with different pest/legal status, whose larvae bore into living wood of healthy/decayed trees, and whose impact has increased alarmingly in recent years. We conducted a regional-scale multi-year (2017–2020) field study to model Cc and Cw distribution and to explore species-specific occupancy-abundance patterns. Records were obtained with 1650 feeding traps placed throughout the region of Extremadura (SW Spain) (41,634 km2) in holm, cork and pyrenean oak woodlands. Catch number (a proxy of abundance) was analysed through GLMMs, LMs and geostatistical interpolation (IK algorithm) to generate catch probability maps. Catch number was extremely variable between trees (traps), stands and years (Cc: 0–252, Cw: 0–219 adults/trap) with no repulsive interspecific association at the tree scale. Explanatory factors in the models (species, sex, year and host oak) and several interactions among them significantly affected catch number. As a whole, Cw was more abundant than Cc, but catch number greatly depended on host tree (Cw: cork > holm > pyrenean oak, Cc: holm > cork > pyrenean oak). Occupancy-abundance patterns were positive with significant occupancy x species interaction. Niche breadth was more than double in Cw (Levins' BA = 0.42) than in Cc (BA = 0.19) and niche overlap almost complete (Pianka's O = 0.98). Our large-scale pioneer study shows that Cc and Cw are widespread in SW Spain, but with huge host-mediated intra- and interspecific geographic variation in abundance, which has critical implications in population management/control strategies. [ABSTRACT FROM AUTHOR]

Summary: In this work, acorn (Quercus suber) starch was first modified by debranching, and then subjected to heat–moisture treatment (HMT) at different temperatures (90 °C, 100 °C and 110 °C). Debranching and HMT could facilitate the aggregation of starch samples. The short‐range order and crystallinity were improved after debranching and HMT. The onset temperature (53.24 °C), peak temperature (63.41 °C), conclusion temperature (75.47 °C) and enthalpy change (11.38 J g−1) of native acorn starch increased after debranching and HMT. The solubility of native acorn starch increased after debranching, whereas the swelling power and freeze–thaw stability decreased. Compared with debranched starch, the freeze–thaw stability increased after HMT, while the swelling power and solubility decreased. Compared with native acorn starch, the water absorption capacity (WAC) was reduced after debranching, while the oil absorption capacity (OAC) was enhanced, and WAC and OAC of the debranched samples decreased after subsequent HMT. The total amount (72.98%, dry basis) of slowly digestible starch and resistant starch of native acorn starch after debranching and HMT increased significantly up to a maximum (80.36%, dry basis). These results indicated that the combination of debranching and HMT could be used as an effective strategy to improve the physicochemical properties of acorn starch. [ABSTRACT FROM AUTHOR]

This study is a contribution to the knowledge of the floristic composition and syntaxonomical significance of Quercus suber woodlands of Tizi Ouzou province, which represent the last remnants of ancient forests. The field surveys were taken in several locations representative of cork oak woodlands, using the Braun-Blanquet method. A matrix of 96 phytosociological relevés and 160 plant taxa was treated with clustering analysis and correspondence analysis. These multivariate analyses showed congruent results and allowed the definition of four main clusters of cork oak woodlands, corresponding to four syntaxa according to synecological and syndynamic gradients. They belong to three associations, of which one is newly described, and two subassociations. They are: Sileno imbricatae-Quercetum suberis ass. nov., a mesophilous association newly described here, on siliceous soils and in the humid ombrotype; Cytiso villosi-Quercetum suberis, a mesophilous association, with two subassociations: quercetosum canariensis, and myrtetosum communis, this later reported for the first time in the study area, and both localized in the humid ombrotype and confined on markedly acid soils; Erico arboreae-Myrtetum communis, thermophilous secondary shrubland association developed in the subhumid ombrotype, on flysch substrates, also identified for the first time in this area. Syntaxonomic, synecological and syndynamic considerations are given for each syntaxon. [ABSTRACT FROM AUTHOR]

Light use efficiency (LUE) models have been widely used to estimate terrestrial gross primary production (GPP). However, the estimation of GPP still has large uncertainties owing to an insufficient understanding of the complex relationship between water availability and photosynthesis. The plant water stress index (PWSI), which is based on canopy temperature, is very sensitive to the plant stomatal opening and has been regarded as a good indicator for monitoring plant water status at the regional scale. In this study, we selected a cork oak plantation in northern China with an obvious seasonal drought as the research object. Using the ground-observed data, we evaluated the applicability of the LUE models with typical water stress scalars (MOD17, MODTEM, EC-LUE, ECM-LUE, SM-LUE, GLO-PEM, and Wang) in a GPP simulation of the cork oak plantation and explored whether the model's accuracy can be improved by applying PWSI to modify the above models. The results showed that among the seven LUE models, the water stress scalar had a greater impact on the model's performance than the temperature stress scalar. On sunny days, the daily GPP simulated by the seven LUE models was poorly matched with the measured GPP, and all models explained only 23–52% of the GPP variation in the cork oak plantation. The modified LUE models can significantly improve the prediction accuracy of the GPP and explain 49–65% of the variation in the daily GPP. On cloudy days, the performance of the modified LUE models did not improve, and the evaporative fraction was more suitable for defining the water stress scalar in the LUE models. The ECM-LUE and the modified GLO-PEM based on PWSI had optimal model structures for simulating the GPP of the cork oak plantation under cloudy and sunny days, respectively. This study provides a reference for the accurate prediction of GPP in terrestrial ecosystems in the future. [ABSTRACT FROM AUTHOR]

Many belowground processes, such as soil respiration and soil–atmosphere VOC (volatile organic compounds) exchange, are closely linked to soil microbiological processes. However, little is known about how changes in plant species cover, i.e. after plant invasion, alter these soil processes. In particular, the response of soil VOC emissions to plant invasion is not well understood.We analysed soil VOC emissions and soil respiration of a Mediterranean cork oak (Quercus suber) ecosystem, comparing soil VOC emissions from a non‐invaded Q. suber woodland to one invaded by the shrub Cistus ladanifer. Soil VOC emissions were determined under controlled conditions using online proton‐transfer time‐of‐flight mass spectrometry. Net soil VOC emissions were measured by exposing soils with or without litter to different temperature and soil moisture conditions.Soil VOC emissions were sensitive to C. ladanifer invasion. Highest net emission rates were determined for oxygenated VOC (acetaldehyde, acetone, methanol, acetic acid), and high temperatures enhanced total VOC emissions. Invasion affected the relative contribution of various VOC. Methanol and acetaldehyde were emitted exclusively from litter and were associated with the non‐invaded sites. In contrast, acetone emissions increased in response to shrub presence. Interestingly, low soil moisture enhanced the effect of shrub invasion on VOC emissions.Our results indicate that shrub invasion substantially influences important belowground processes in cork oak ecosystems, in particular soil VOC emissions. High soil moisture is suggested to diminish the invasion effect through a moisture‐induced increase in microbial decomposition rates of soil VOC. [ABSTRACT FROM AUTHOR]

The oak pinhole borer, Platypus cylindrus F., mainly colonizes oaks (Quercus sp.), and it is considered among the most serious pests of cork oak (Quercus suber L.). Despite being traditionally considered as a secondary pest in thermophilic oak woodlands, outbreaks seem to be more frequent throughout the Mediterranean Basin thus becoming a growing forest health concern. In the Iberian Peninsula, this insect mainly attacks cork oaks (Q. suber) causing intense stress to mature trees specially after cork harvesting season. In this study, we investigated the summer flight phenology of P. cylindrus in six stands located in north‐eastern Spain. We recorded the number of insects trapped in pheromone‐baited traps from late April to early September of 2021, and computed sex ratio, average date of flight and season flight curve in each plot. We fitted a GAM model to evaluate how population dynamics are driven by date and climatic factors. A total of 1795 insects were collected during the sampling period. Population peaks occurred from late May to mid‐August. The fitted GAM predicted changes in the number of captures throughout the summer varying with microclimatic conditions. In addition, diversity of trapped non‐target Curculionidae resulted moderate with low evenness including either ambrosia or bark beetles. This study represents the first attempt at modelling P. cylindrus flight, thus providing insights into the association between climate, pests and forestry. [ABSTRACT FROM AUTHOR]

This analysis of 238U, 226Ra and 210Pb transfer factors from the soil to the leaves of different native broadleaf trees at sites previously modified by uranium presence and at the site of background radioactivity levels, was conducted using data from a few available studies from the literature. The broadleaf tree species Quercus ilex, Quercus suber, Eucalyptus camaldulensis, Quercus pyrenaica, Quercus ilex rotundifolia, Populus sp. and Eucalyptus botryoides Sm. at the affected sites and Tilia spp. and Aesculus hippocastanum L. at the back ground site were in cluded in the study regardless of the deciduous or evergreen origins of the leaves. In the papers cited here, data about basic soil parameters: pH, total Ca [gkg-1], sand [%], and silt + clay [%] fractions were also available. All the collected data of activity concentration [Bqkg-1] dry weight in the soil (n=14) which was in the range: 22-6606 for 238U, 38-7700 for 226Ra, and 37-7500 for 210Pb, and the tree leaves in the range: 2.7-137.6 for 238U (n=10), 2.6-134.2 for 226Ra (n=14), and 27-77.2 for 210Pb (n=14), indicated that it was normally distributed after log-transformation. The present study was conducted under the hypothesis that biological differences between the examined broadleaf tree species have a lesser influence on the transfer factors of the investigated radionuclides from soil to tree leaves compared to the impact of the soil parameters and radionuclides activity concentrations in the soil. Consequently, it was examined whether 238U, 226Ra, and 210Pb soil-to-leaves transfer factor values for average broadleaf species could be predicted statistically in the first approximation based on their activity concentration in the soil and at least one basic soil parameter using multiple linear regression. [ABSTRACT FROM AUTHOR]

Iii Portugal. fungal symbionts of the ambrosia beetle Plaoria' crlindrus inoculaaffect tree vigor of cork oak (Quercia· suber) and are linked with the cork decline process. Fungal symbionts play cnicial role.4 in the life history of and ambrosia beetles and recent work indicates complex interactions on chefungal and plant metabolic level. Colonized trees may respond with an array infocurrently unknown volatile metabolites being indicative of such interactions, acting as infochemicals with their environment. In this study. we examined volatile organic compounds (VOCK) of cork oak seedlings wound inoculated interwith strains of three fungal associates of P. cvli, ith·us (Ridtbelea, nonteou, quercina, and Cemton'stiopsis sp. nov.) over a 45-day period by means thermodesorption gas chromatography-mass spectrometry techniques. Fungal strains induced largely quantitative but species-specific changes among 58 VOCs characterized. Overall. monoterpenes-the major volatiles cork oak foliage-were significantly reduced. possibly a result of fungal ophiostransformation. Acetophenone, sulcatone. and nonanal-volatiles known mediating ambrosia beetle behavior-increased in response to fungal inoculaaffect lion. Qualitative VOC profiles of excised tissue of wood lesions (21 VOCs) and pure ftingal cultures (60 VOCs) showed little overlap with seedling VOCs. indicating their plant-derived but fungal-induced origin. This chefungal moecological study expands on the limited knowledge of VOCs as infocurrently chemicals emitted from oak trees threatened by oak decline in relation to beetle-vectored ophiostomatoid fungi. It opens new avenues of research to clarify mutualistic or pathogenic aspects of these complex symbiotic interwith actions and develop new control strategies for P. o, lindrus. including its mycobiota. [ABSTRACT FROM AUTHOR]