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ABSTRACT Oxygen (δ18O) and hydrogen (δ2H) stable isotope ratios are tightly coupled in precipitation and, albeit damped, in leaf water, but are often decoupled in tree‐ring cellulose. The environmental and physiological conditions in which this decoupling occurs are not yet well understood. We investigated the relationships between δ18O and δ2H and tree‐ring width (TRW), tree crown volume, tree age and climate in silver fir and Douglas‐fir and found substantial differences between δ18O and δ2H. Overall, δ18O–δ2H correlations were weak to absent but became significantly negative under high summer vapour pressure deficit (VPD). δ18O and δ2H had positive and negative nonlinear relationships with TRW, respectively, with clear relationships at the site and tree levels for silver fir and, to a lesser extent, for Douglas‐fir. Age trends for silver fir were weakly negative in δ18O but positive in δ2H. Tree crown volume and δ18O or δ2H had no significant relationships. Most strikingly, δ18O strongly depended on spring climate (precipitation and VPD), whereas δ2H depended on summer climate (temperature and VPD) for both species. Our study shows that the δ18O–δ2H decoupling in tree‐ring cellulose in two temperate conifer species could be highlighted by their contrasting relationships to climate and tree intrinsic variables (TRW, age). [ABSTRACT FROM AUTHOR]

The present work has experimentally determined the specific fracture energy of the hardwood species silver birch (Betula pendula), which in recent times has caught increased attention for utilization in structural applications. The single-edge-notched beam loaded in three-point-bending was utilized for evaluating the fracture energy with the work-of-fracture method. In addition to birch, Norway spruce (Picea abies) was utilized as a reference material. The effect of two different geometries of the fracture area for each species was evaluated—one triangular and one rectangular fracture area. It should be noted that the geometry of the fracture area did influence the evaluated fracture energy, and this influence was not consistent between species. This was likely in part due to manufacturing difficulties with the triangular fracture area. In addition to the experimental testing, a numerical 2d-model including linear strain-softening behavior was used for comparative simulations. The numerical 2d-models showed reasonable agreement with the experimental results regarding the global load vs. displacement response, despite their relative simple nature. The specific fracture energy for the spruce specimens was evaluated to 221 J/ m 2 and for the birch specimens to 656 J/ m 2 . Consequently, the present work implies a marked increase in specific fracture energy for birch, compared to spruce. This increase in specific fracture energy could potentially have a large influence on the failure behavior of birch when used in structural applications which is something that needs to be considered in future work. [ABSTRACT FROM AUTHOR]

The article discusses Olzreuter Lake in south-western Germany, highlighting its ecological significance and archaeological relevance. The lake is surrounded by diverse habitats and is part of a Special Area of Conservation. Sediment cores from the lake reveal information about the environmental history of the region, including pollen records dating back to different periods. The research was conducted by various institutions and funded by the Senckenberg Centre for Human Evolution and Paleoenvironment in Tübingen. [Extracted from the article]

SUMMARY Somatic embryogenesis (SE) is a powerful model system for studying embryo development and an important method for scaling up availability of elite and climate‐adapted genetic material of Norway spruce (Picea abies L. Karst). However, there are several steps during the development of the somatic embryo (Sem) that are suboptimal compared to zygotic embryo (Zem) development. These differences are poorly understood and result in substantial yield losses during plant production, which limits cost‐effective large‐scale production of SE plants. This study presents a comprehensive data resource profiling gene expression during zygotic and somatic embryo development to support studies aiming to advance understanding of gene regulatory programmes controlling embryo development. Transcriptome expression patterns were analysed during zygotic embryogenesis (ZE) in Norway spruce, including separated samples of the female gametophytes and Zem, and at multiple stages during SE. Expression data from eight developmental stages of SE, starting with pro‐embryogenic masses (PEMs) up until germination, revealed extensive modulation of the transcriptome between the early and mid‐stage maturing embryos and at the transition of desiccated embryos to germination. Comparative analysis of gene expression changes during ZE and SE identified differences in the pattern of gene expression changes and functional enrichment of these provided insight into the associated biological processes. Orthologs of transcription factors known to regulate embryo development in angiosperms were differentially regulated during Zem and Sem development and in the different zygotic embryo tissues, providing clues to the differences in development observed between Zem and Sem. This resource represents the most comprehensive dataset available for exploring embryo development in conifers. [ABSTRACT FROM AUTHOR]

This article presents results obtained for the chipless cutting of wood using different cutting heads. Wood processing in forestry and the demand for firewood are currently increasing, so it is necessary to apply appropriate tools to the existing process, which will be sufficient for fast and highquality operations. Four groups of cutting knives were used for experimental measurements, where the influence of the cutting knife edge on the cutting process was determined. The cutting knives were always made of the same material and with the same blade angle - 30°. Measurements were made on spruce (Picea abies), beech (Fagus sylvatica), and willow (Salix caprea) trees. The size of the Fc cutting force was selected as the monitored variable, and then the dependent factors (kind of wood, wood diameter, cutting knife) were monitored in terms of their influence on the size of this Fc cutting force and thus also on the energy consumption. Based on the statistical evaluation, the most suitable shape of the cutting edge of the knife was selected, with this shape of the cutting edge, a reduction in the cutting force Fc was achieved for selected woods. [ABSTRACT FROM AUTHOR]

Wildlife damage to forests has become an increasingly serious problem in recent years, and its impact is exacerbated by ongoing climate change. Rising temperatures, prolonged droughts, uneven precipitation distribution, and other factors affect forest ecosystems, which, in turn, affect cloven-hoofed animal populations, their food preferences, and ultimately, the extent of damage they cause. Based on 133 references, this review article focuses on the relationships between wildlife damage and climate change and presents possible strategies to address this issue in the Czech Republic. Wildlife damage includes not just browsing and fraying in natural and artificial regeneration but also damage to trees from bark stripping and the lesser-known rooting of seedlings. Concerning tree species, browsing is most damaging to silver fir (Abies alba Mill.) and sycamore maple (Acer pseudoplatanus L.). The enticement to wildlife increases as the proportion of the tree species in the stand decreases. Browse damage is more severe at the edge of the stand. Bark stripping and secondary rot cause the most damage to the production quality of Norway spruce (Picea abies [L.] Karst.). Total wildlife damage increases with elevation. Combined with the progress of climate change, game-induced damage significantly restricts close-to-nature forest management practices and limits the use of adaptive measures in response to climate change. In addition, mixed forests with species that attract wildlife and the rapid increase in the number of clearings following bark beetle salvage logging significantly increase game pressure. This is primarily the result of the overpopulation of native and introduced game species and the considerable inconsistency between forest and hunting management practices, with the latter not respecting the principle of ecologically tolerable game damage. [ABSTRACT FROM AUTHOR]

In forest ecosystems, the browsing activity of large wild herbivores (LWH) often leads to reduced tree and plant diversity, diminished biomass production, and challenges in achieving forest management objectives. Our case study focuses on assessing the impact of LWH browsing during the initial stages of forest growth by comparing fenced plots (F plots) with excluded LWH and control plots (C plots) with the presence of LWH. The experiment took place at the Hukavský Grúň research site in the Poľana Mts., characterized by a high red deer (Cervus elaphus L.) population. Fifteen F plots and fifteen C plots, all situated within mixed maternal forests, were established in the 2023 growing season. Thus, circular plots with a radius of 2.5 m were utilized, and comprehensive data were collected on young trees (excluding those under 10 cm in height), covering tree species, positions, heights, and stem diameters. Species-specific allometric relations were employed to calculate the aboveground biomass of each tree, contributing to the overall biomass stock on a plot basis. A comparison between F and C plots revealed a prevalence of silver fir (Abies alba Mill.) in F plots, while European beech (Fagus sylvatica L.) dominated C plots. F plots exhibited higher tree species diversity (4.5 species), contrasting with the lower diversity (2.0 species) and absence of silver fir in C plots. The F plots also demonstrated greater tree density and sizes, resulting in substantial differences in aboveground biomass stocks. Browsing in C plots predominantly affected tree height rather than stem diameter, leading to a bigger height-to-diameter ratio in F plots compared to C plots. We suggest that fencing as a method to exclude LWH might be economically expensive and provide a temporary solution limited by the functionality of the fence. Therefore, the primary strategy for safeguarding the future of silver fir may lie in regulating LWH populations to a reasonable threshold. [ABSTRACT FROM AUTHOR]

Heterobasidion parviporum is a fungal pathogen that is drastically damaging Norway spruce (Picea abies) in Europe. The infections will result in root and stem rot, causing significant economic losses for forest owners. Previous studies have shown that the PaLAR3 gene, which encodes the leucoanthocyanidin reductase enzyme, can increase resistance to H. parviporum in Norway spruce. The presence of the B allele at the PaLAR3 locus has been associated with higher (+)‐catechin concentrations and increased enzyme production in inoculation experiments, resulting in inhibited pathogen growth. The control of H. parviporum involves a multifaceted approach, including silvicultural and sustainable forestry practices, genetic resistance and chemical/biological control. In this study, we determined the PaLAR3 genotypes in a representative sample of Norway spruce breeding materials from southern Finland and examined their effect on necrosis caused by H. parviporum in spruce stems. The results showed that the homozygous PaLAR3BB genotype was present in only 9% of the trees. However, the necrotic area interacted with homozygous PaLAR3BB under low‐water treatment. These findings support the idea that the PaLAR3 locus may be a valuable marker for identifying P. abies resistance to different strains of Heterobasidion parviporum. [ABSTRACT FROM AUTHOR]

Porous hydrogels have brought more advantages than conventional hydrogels when used as chromatographic materials, controlled release vehicles for drugs and proteins, matrices for immobilization or separation of molecules and cells, or as scaffolds in tissue engineering. Polysaccharide-based porous hydrogels, in particular, can address challenges related to bioavailability, solubility, stability, and targeted delivery of natural antioxidant compounds. Their porous structure enables the facile encapsulation and controlled release of these compounds, enhancing their therapeutic effectiveness. In this context, in the present study, the cryogelation technique has been adopted to prepare novel dextran (Dx)-based porous hydrogels embedding polyphenol-rich natural extract from Picea abies spruce bark (SBE). The entrapment of the SBE within the Dx network was proved by FTIR, SEM, and energy-dispersive X-ray spectroscopy (EDX). SEM analysis showed that entrapment of SBE resulted in denser cryogels with smaller and more uniform pores. Swelling kinetics confirmed that higher concentrations of Dx, EGDGE, and SBE reduced water uptake. The release studies demonstrated the effective stabilization of SBE in the Dx-based cryogels, with minimal release irrespective of the approach selected for SBE incorporation, i.e., during synthesis (~3–4%) or post-synthesis (~15–16%). In addition, the encapsulation of SBE within the Dx network endowed the hydrogels with remarkable antioxidant and antimicrobial properties. These porous biomaterials could have broad applications in areas such as biomedical engineering, food preservation, and environmental protection, where stability, efficacy, and safety are paramount. [ABSTRACT FROM AUTHOR]

The substantial volume of timber recovered from the aftermath of the eruption of Vesuvius in 79 AD offers a valuable resource for gaining insights into the timber trade during Roman times. Silver fir emerges as the dominant species in construction within the Vesuvian region. While this species once thrived more abundantly along the Apennines, it now exists only in small, isolated groups, raising the possibility that the Romans contributed to its scarcity. Nevertheless, the origins of the substantial quantity of silver fir wood discovered in Pompeii, Herculaneum, and the surrounding areas remain unclear. This study examines 35 wood samples obtained during the excavation of the Moregine site, an ancient commercial port located a mere 600 m to the south of Pompeii's walls. Dendrochronological analysis successfully dated 19 out of the 35 samples. Despite silver fir not being the ideal species for dendroprovenancing analysis, certain observations can be made regarding its likely foreign origin. The correlation with chronologies of different species of Central European origin, the presence of species such as spruce/larch among the structural material and the existence of different groups among the material analysed are strong indications that demonstrate the foreign origin of at least some of the timber. Dendrochronological data further support that the wood trade played a strategically significant role in the economy of ancient Rome. [ABSTRACT FROM AUTHOR]

The segmentation of individual trees based on deep learning is more accurate than conventional meth- ods. However, a sufficient amount of training data is mandatory to leverage the accuracy potential of deep learning-based approaches. Semi-supervised learning techniques, by contrast, can help simplify the time-consuming labelling process. In this study, we introduce a new semi-supervised tree segmen- tation approach for the precise delineation and classification of individual trees that takes advantage of pre-clustered tree training labels. Specifically, the instance segmentation Mask R-CNN is combined with the normalized cut clustering method, which is applied to lidar point clouds. The study areas were located in the Bavarian Forest National Park, southeast Germany, where the tree composition includes coniferous, deciduous and mixed forest. Important tree species are European beech (Fagus sylvatica), Norway spruce (Picea abies) and silver fir (Abies alba). Multispectral image data with a ground sample distance of 10 cm and laser scanning data with a point density of approximately 55 points/m 2 were acquired in June 2017. From the laser scanning data, three-channel images with a resolution of 10 cm were generated. The models were tested in seven reference plots in the national park, with a total of 516 trees measured on the ground. When the color infrared images were used, the experiments demonstrated that the Mask R-CNN models, trained with the tree labels generated through lidar-based clustering, yielded mean F1 scores of 79 % that were up to 18 % higher than those of the normalized cut baseline method and thus significantly improved. Similarly, the mean over- all accuracy of the classification results for the coniferous, deciduous, and standing deadwood tree groups was 96 % and enhanced by up to 6 % compared with the baseline classification approach. The experiments with lidar-based images yielded slightly worse (1–2 %) results both for segmentation and for classification. Our study demonstrates the utility of this simplified training data preparation pro- cedure, which leads to models trained with significantly larger amounts of data than is feasible with with manual labelling. The accuracy improvement of up to 18 % in terms of the F1 score is further evidence of its advantages. [ABSTRACT FROM AUTHOR]

Mistletoes are xylem-tapping hemiparasites that rely on their hosts for water and nutrient uptake. Thus, they impair tree performance in the face of environmental stress via altering the carbon and water relations and nutritional status of trees. To improve our understanding of physiological responses to mistletoe and ongoing climate change, we investigated radial growth, stable carbon and oxygen isotopic signals, and elemental composition of tree rings in silver fir (Abies alba Mill.) and Scots pine (Pinus sylvestris L.) forests infested with Viscum album L. We compared temporal series (1990–2020) of basal area increment (BAI), intrinsic water-use efficiency (iWUE), oxygen isotope composition (δ18O), nutrient concentrations and stoichiometric ratios between non-infested (NI) and severely infested (SI) fir and pine trees from populations located close to the xeric distribution limit of the species in north-eastern Spain. The SI trees showed historically higher growth, but the BAI trend was negative for more than three decades before 2020 and their growth rates became significantly lower than those of NI trees by the mid-2010s. Mistletoe infestation was related to an enhanced sensitivity of radial growth to vapour pressure deficit (atmospheric drought). The SI trees showed less pronounced iWUE increases (fir) and lower iWUE values (pine) than NI trees. The lower tree-ring δ18O values of SI trees may be the result of several superimposed effects operating simultaneously, including leaf-level evaporative enrichment, source water isotopic signals, and anatomical and phenological differences. We observed a deterioration of potassium (K) nutrition in tree-ring wood of both species in SI trees, along with accumulation of manganese (Mn). We suggest that such nutritional patterns are driven by the indirect effect of mistletoe-induced drought stress, particularly in pine. The combined analyses of different physiological indicators imprinted on tree rings provided evidence of the progressive onset of carbon, water and nutrient imbalances in mistletoe-infested conifers inhabiting seasonally dry regions. [ABSTRACT FROM AUTHOR]

SUMMARY: The osmotic resistance mechanism has been extensively studied in whole plants or plant tissues. However, little is known about it in embryogenic tissue (ET) which is widely used in plant‐based biotechnological systems. Suberin, a cell wall aliphatic and aromatic heteropolymer, plays a critical role in plant cells against osmosis stress. The suberin regulatory biosynthesis has rarely been studied in gymnosperms. Here, PaMYB11, a subgroup 11 R2R3‐MYB transcription factor, plays a key role in the osmotic resistance of Norway spruce (Picea abies) ETs during cryoprotectant pretreatment. Thus, RNA‐seq, histological, and analytical chemical analyses are performed on the stable transformations of PaMYB11‐OE and PaMYB11‐SRDX in Norway spruce ETs. DAP‐seq, Y1H, and LUC are further combined to explore the PaMYB11 targets. Activation of PaMYB11 is necessary and sufficient for suberin lamellae deposition on Norway spruce embryogenic cell walls, which plays a decisive role in ET survival under osmotic stress. Transcriptome analysis shows that PaMYB11 enhances suberin lamellae monomer synthesis by promoting very long‐chain fatty acid (VLCFA) synthesis. PaPOP, PaADH1, and PaTET8L, the first two (PaADH1 and PaPOP, included) involved in VLCFA synthesis, are proved to be the direct targets of PaMYB11. Our study identified a novel osmotic response directed by PaMYB11 in Norway spruce ET, which provides a new understanding of the resistance mechanism against osmosis in gymnosperms. Significance Statement: In brief, our data suggested that the activation of PaMYB11 enhances SL accumulation by promoting very long‐chain fatty acids synthesis in Picea abies embryogenic tissues. PaADH1, PaPOP and TET8L are direct targets of PaMYB11. However, the correlation between very long‐chain fatty acids synthesis and the expression of PaADH1, PaPOP and TET8L is still unclear. It provides novel insight into the resistance mechanism against osmosis in gymnosperms. [ABSTRACT FROM AUTHOR]

We studied how management intensity and climate severity affect volume growth, timber yield, carbon stocks, and the amount of deadwood in Scots pine (Pinus sylvestris (L.)), Norway spruce (Picea abies (L.) Karst.), and silver birch (Betula pendula Roth.) dominated stands in the Republic of Karelia and Arkhangelsk region of northwest Russia. Using the forest ecosystem model (SIMA) under different climates (current and representative concentration pathway scenarios, RCP4.5 and RCP8.5), no-thinning, low, medium, and high intensity thinning rotational forestry regimes were simulated. Under RCPs, the volume growth and timber yield (5%–53%), carbon stocks (1%–22%), and deadwood amounts (11%–75%) increased for all Scots pine and silver birch stands. The use of low intensity management increased volume growth and carbon stocks (3%–16%) and deadwood amount (up to 60%) under RCPs, but not timber yield (±3%) in these stands. For Norway spruce stands, the volume growth (5%–26%), timber yield (23%–75%), and carbon stocks (5%–15%) decreased under RCP8.5, but deadwood amount increased (up to 142%). Intensive management increased volume growth (4%–19%), timber yield (4%–63%), carbon stocks (up to 14%), and deadwood amounts (up to 49%). Our results highlight that effects of climate severity and management intensity are site and species-specific for Eurasian's boreal forests. [ABSTRACT FROM AUTHOR]

We introduce a class of proper scoring rules for evaluating spatial point process forecasts based on summary statistics. These scoring rules rely on Monte Carlo approximations of expectations and can therefore easily be evaluated for any point process model that can be simulated. In this regard, they are more flexible than the commonly used logarithmic score and other existing proper scores for point process predictions. The scoring rules allow for evaluating the calibration of a model to specific aspects of a point process, such as its spatial distribution or tendency toward clustering. Using simulations, we analyze the sensitivity of our scoring rules to different aspects of the forecasts and compare it to the logarithmic score. Applications to earthquake occurrences in northern California, United States and the spatial distribution of Pacific silver firs in Findley Lake Reserve in Washington highlight the usefulness of our scores for scientific model selection. [ABSTRACT FROM AUTHOR]

Masting, the spatial synchronization of interannual variation in seed production, can enhance reproductive efficiency through positive density‐dependent processes (DD) that result in economies of scale (EOS), such as decreased pollen limitation and predator satiation in years of high reproduction.While the general occurrence of such EOS effects has been documented for masting species, few studies simultaneously investigated how spatial and temporal variation in reproduction affects pollination and predation. Furthermore, it is unclear whether the same mechanisms apply to co‐occurring species with different levels of conspecific density, pollen limitation, and seed defences.Here, we use a long‐term dataset with high spatial resolution of seed production of European beech (Fagus sylvatica), Norway spruce (Picea abies), and silver fir (Abies alba) in a primeval montane forest to investigate the relationship between reproductive effort, pollination efficiency and predispersal predation by insects.We found that, along the temporal axis, the proportion of sound (fertilized and unpredated) seeds correlated positively with annual seed production over the 14‐year study period in all three species, most strongly in beech and only weakly in silver fir. Moreover, the results show that in beech, spatial seed density interacts with plot‐wide annual seed rain to enhance DD effects on seed predation, suggesting additive effects of synchronous reproduction on fitness benefits.Synthesis: For both pollination and predispersal predation in beech and spruce, the strongest DD effects occur at low levels of reproduction and quickly reach asymptotes at higher levels, suggesting the presence of thresholds in different EOS mechanisms. As variability and synchrony in mast‐seeding are expected to decline with climate change, EOS effects driven by DD may remain stable until the threshold is reached, at which sudden declines would result in devastating effects on the availability of viable seeds for germination and recruitment. [ABSTRACT FROM AUTHOR]

This study was conducted to provide information regarding the quality of gluing of Silver fir wood (Abies alba Mill.) planed at different feed speeds after thermal modification. Four groups of sixteen air-dried fir samples were prepared. Three groups were thermally modified at different temperatures (160°C, 190°C, and 220°C) for 3 hours. The processes that followed included planning with two feed speeds (half of the samples at 3m/min and the other half at 10 m/min), the gluing, and finally, conducting mechanical tests to assess shear strength and wood failure. The gluing shear strength underwent a progressive decrease with increasing modification temperature for both feed speeds, with reductions ranging from 1.37% to 14.63% compared to natural wood. Wood failure did not show a linear relationship, with a decrease at 160°C but an increase at higher temperatures compared to natural wood. The feed speed had a significant effect on gluing shear strength, with higher feed speed resulting in decreased strength for natural wood but increased strength for thermally modified wood. Thermal modification of fir wood at temperatures of 220°C had a detrimental effect on the gluing shear strength and wood failure. This was caused by the deterioration of wood components and alterations in mechanical properties. The results of this study offer significant knowledge for improving the gluing process and establishing appropriate parameters for thermally modified fir wood. This type of wood has potential uses in the wood sector, specifically in the manufacturing of engineered wood products. [ABSTRACT FROM AUTHOR]

This study examines the structural dynamics and species composition of the "Ravna Vala" old-growth forest on Bjelašnica Mountain, focusing on neighborhood effects on tree growth. Data from a permanent 1-hectare plot, measured 2012 and 2023, revealed that silver fir (Abies alba Mill.) constitutes nearly 73% of the total volume, while beech (Fagus sylvatica L.) dominates in tree numbers. The forest displays a reverse J-curve pattern, with significant mortality in smaller diameter classes. Using indices for species intermingling, aggregation, and competition, the study found that diameter at breast height (dbh) and the aggregation index significantly influenced growth, especially for silver fir and beech. Additional factors like the mixing index and competition index were significant for beech growth. These results underscore the complexity of species interactions and the importance of tailored management strategies. Future research should explore factors limiting fir regeneration and the link between disturbances and beech recruitment. Management practices that mimic natural disturbances, such as creating larger gaps, are recommended to enhance species diversity and forest resilience. [ABSTRACT FROM AUTHOR]

Forest ecosystems are facing increasing challenges like natural disturbances. Despite positive disturbance impacts on the diversity of several taxonomic groups, there are still concerns, whether the drastic canopy opening can lead to a turnover from forest to open habitat species.We sampled arthropods along a disturbance gradient in Norway spruce (Picea abies)‐dominated protected areas across Central Europe using Malaise traps and metabarcoding.To analyse changes in arthropod communities in terms of forest affinities along the disturbance gradient, we explored the potential of a list of forest affinities (LFA) that provides information about species affinities from closed forest to open habitats.Our results show that the mean forest affinity decreased with increasing disturbance severity. This trend was accompanied by a decrease in forest‐associated species as well as community shifts for open and mixed habitat species. Responses varied between taxa and were most apparent in Coleoptera.Overall, the changes did not come with a complete replacement of forest specialists by species with higher affinities for mixed and open landscapes nor a drastic loss of forest species. Furthermore, we observed severely disturbed plots with a high mean forest affinity and vice versa, which calls for further studies using these kinds of species classifications.The LFA can provide additional information how species associated with forests habitats can react to environmental changes beyond increasing amounts of deadwood resources. Using additional trapping methods and determination techniques might increase the explanatory power of such analyses along ecological gradients. [ABSTRACT FROM AUTHOR]

Disentangling the factors influencing the climate sensitivity of trees is crucial to understanding the susceptibility of forests to climate change. Reducing tree-to-tree competition and mixing tree species are two strategies often promoted to reduce the drought sensitivity of trees, but it is unclear how effective these measures are in different ecosystems. Here, we studied the growth and physiological responses to climate and severe droughts of silver fir and Douglas-fir growing in pure and mixed conditions at three sites in Switzerland. We used tree-ring width data and carbon (δ13C), oxygen (δ18O) and hydrogen (δ2H) stable isotope ratios from tree-ring cellulose to gain novel information on water relations and the physiology of trees in response to drought and how tree species mixture and competition modulate these responses. We found significant differences in isotope ratios between trees growing in pure and mixed conditions for the two species, although these differences varied between sites, e.g. trees growing in mixed conditions had higher δ13C values and tree-ring width than trees growing in pure conditions for two of the sites. For both species, differences between trees in pure and mixed conditions regarding their sensitivity to temperature, precipitation, climatic water balance and vapor pressure deficit were minor. Furthermore, trees growing in pure and mixed conditions showed similar responses of tree-ring width and isotope ratios to the past severe droughts of 2003, 2015 and 2018. Competition had only a significantly negative effect on δ13C of silver fir, which may suggest a decrease in photosynthesis due to higher competition for light and nutrients. Our study highlights that tree species mixture may have only moderate effects on the radial growth and physiological responses of silver fir and Douglas-fir to climatic conditions and that site condition effects may dominate over mixture effects. [ABSTRACT FROM AUTHOR]

Dental fear and anxiety (DFA) is known as an immense challenge in oral healthcare, which can result in compromised oral health, pain, and uncomfortable treatment. The objective of this study was to analyze the effect of essential-oil vaporization on acute anxiety of patients in dental practices. Four dental practices used five weekly cycles of vaporization with each scent: Orange (Citrus sinensis), Swiss Pine (Pinus cembra), Good Mood (blended essential oils: Citrus sinensis, Citrus aurantifolia, Citrus limon, Osmanthus fragrance (5%)), Forest Walk (blended essential oils: Abies grandis, Pinus cembra, Myrtus communis c. t. 1,8-cineol, Abies alba, Citrus paradisi, Abies sibirica, Pseudotsuga menziesii, Vetiveria zizanoides), and water. Acute anxiety was the primary outcome (state-trait-anxiety inventory (STAI-S)). Secondary outcomes were trait anxiety (STAI-T), dental anxiety (Kleinknecht dental fear survey), and pain perception in treatment (numeric rating scale). Across all patients (n = 486), STAI-S was slightly higher in the control group (40.7 ± 11.6) than in the intervention groups (38.4 ± 10.5). Post-hoc analyses revealed that the effect is only robust for the subgroup of female patients (n = 296, p = 0.044). We also conducted a post-hoc additional analysis on a subpopulation with an increased level of STAI-T ≥ 42 (n = 131 patients). For this group the difference in acute anxiety between the control group (51.1 ± 11.9, n = 30) vs. the intervention groups (46.8 ± 9.6, n = 118) was significant (T = 4.39, p = 0.0379). The results of the study indicate a promising potential of essential-oil vaporization to alleviate dental anxiety, particularly in the subgroups of patients with a high level of trait anxiety, and particularly in female patients. The calming effects of the essential-oil vaporization were also highlighted by the anecdotical statements of the dental-practice staff. The anxiety-reducing role of essential-oil vaporization alone and as one part of combined techniques to counter DFA should be further explored using multi-perspective methodological approaches in research. [ABSTRACT FROM AUTHOR]

Our study delved into the relationship between root‐associated fungi, gene expression and plant morphology in Norway spruce cuttings derived from both slow‐and fast‐growing trees. We found no clear link between the gene expression patterns of adventitious roots and the growth phenotype, suggesting no fundamental differences in the receptiveness to fungal symbionts between the phenotypes. Interestingly, saplings from slow‐growing parental trees exhibited a higher richness of ectomycorrhizal species and larger roots. Some ectomycorrhizal species, typically found on mature spruces, were more prevalent on saplings from slow‐growing spruces. The ericoid mycorrhizal fungus, Hyaloscypha hepaticola, showed a stronger association with saplings from fast‐growing spruces. Moreover, saplings from slow‐growing spruces had a greater number of Ascomycete taxa and free‐living saprotrophic fungi. Aboveground sapling stems displayed some phenotypic variation; saplings from fast‐growing phenotypes had longer branches but fewer whorls in their stems compared to those from the slow‐growing group. In conclusion, the observed root‐associated fungi and phenotypic characteristics in young Norway spruces may play a role in their long‐term growth rate. This suggests that the early interactions between spruces and fungi could potentially influence their growth trajectory. [ABSTRACT FROM AUTHOR]

Background: Norway spruce (Picea abies) resin‐based products are used in human medicine. A resin‐based otic rinse also could be useful in supportive care of canine otitis externa (COE), yet information on its antimicrobial effect against canine pathogens or ototoxicity is lacking. Objectives: To investigate the antimicrobial properties and ototoxicity of a commercial resin‐based otic product. Materials and Methods: Antimicrobial effect was evaluated using a standardised challenge test on Staphylococcus pseudintermedius, Corynebacterium auriscanis, Pseudomonas aeruginosa, Escherichia coli, Malassezia pachydermatis, and Streptococcus halichoeri strains to measure reduction in growth after 24 h exposure to the product. Effect on cell morphology was investigated by exposing S. pseudintermedius, C. auriscanis, P. aeruginosa and M. pachydermatis to the product in 20% and 100% (v/v) concentrations for 6, 24 and 48 h, and evaluating cells by transmission (TEM) and scanning (SEM) electron microscopy. An in vitro microbial kill–rate assay also was performed. Auditory brain stem response test, clinical evaluation and postmortem histological evaluation of ear canals were undertaken on experimental guinea pigs treated with the test product or saline controls. Results: The product showed >log 5 growth reduction for all strains in the challenge test. TEM and SEM images showed clear changes in the cells' inner structures and deterioration of cells, and 100% (v/v) test product exposure induced microbial killing in 1–2 h. Ototoxicity was not detected in guinea pigs. Conclusions and Clinical Relevance: The product may be an option in supportive care of COE because of antimicrobial effects and lack of ototoxic properties in a guinea pig model. [ABSTRACT FROM AUTHOR]

Simple Summary: Determining the ecological niche breadth of various organisms is a key objective in contemporary biological research. Studies of this type play a significant role in describing biotic interactions, which is becoming particularly important in the context of observed climate change. A method has been developed that enables the monitoring of the impact of climatic changes at the local level, in specific tree stands. The statistical foundations of the method enable the computation of errors of estimation. The method offers a high precision and explains approximately 80% of the variation in the niche breadth of bark beetles on natural traps, while the mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe—for example—the impact of observed climate change on the population dynamics of bark beetles. The results suggest a need for further research to derive regression equations for firs growing in different regions of Europe. Bark beetles are a significant link in the chain of diseases that lead to the accelerated dying of firs (Abies alba Mill.), a key species in the cultivation of stable mixed-tree stands. The aim of this work was to evaluate biotic interactions in populations of bark beetles that colonised natural traps made from firs. The tested hypothesis was that the niche breadth of the species increases with the increasing density of the population. The research was carried out in near-natural forests containing fir, growing in the Suchedniów-Oblęgorek Landscape Park in central Poland. Data were collected from 30 traps trees and 30 windfalls in the years 2010–2023. Cryphalus piceae Ratz. prefers heavily weakened trees, as shown by the fact that it colonised all of the natural traps, which lack any defensive reactions. The sampling method used in the study proved effective, as confirmed by the segregation of the niches of all of the bark beetles. Using nonlinear regression (linearisable model and piecewise linear regression), models were constructed that describe the niche breadths of the bark beetles. The niche parameter is correlated with the density of colonisation. The derived models explain around 77–84% of the variation in the niche breadth of bark beetles on natural traps. The mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe—for example—the impact of observed climate change on the population dynamics of bark beetles. [ABSTRACT FROM AUTHOR]

The damping of spruce wood is analysed at different moisture content levels for the first three vibration modes of tangentially and radially vibrating samples. Two methods were used to determine the damping. The first was the vibration envelope fitting as an improved version of the well-known logarithmic decrement, and the second was the newer and recently increasingly used wavelet transform. Both methods showed that the damping of spruce wood first decreases and then increases with moisture content, with the damping in the first vibration mode being about 9% higher in the radial direction than in the tangential direction. In the second and third vibration modes, the damping in the tangential direction was higher than in the radial direction by about 10% and 8.8%, respectively. The measured damping factors from the envelope fitting had, on average, 15.9% higher values than those from the wavelet transform. It can be concluded from the results that the wavelet transform is more accurate for determining the damping factor, as it enables the decoupling of multi-degree of freedom systems if mode coupling is present. [ABSTRACT FROM AUTHOR]

This study aims to investigate the vegetative buds from Picea abies (spruce), naturally found in a central region of Romania, through a comprehensive analysis of the chemical composition to identify bioactive compounds responsible for pharmacological properties. Using HPLC/derivatization technique of GC-MS and quantitative spectrophotometric assays, the phenolic profile, and main components of an ethanolic extract from the buds were investigated. The essential oil was characterized by GC-MS. Moreover, the antioxidant activity with the DPPH method, and the antimicrobial activity were tested. Heavy metal detection was performed by graphite furnace atomic absorption spectrometry. The main components of the alcoholic extract were astragalin, quercetin, kaempferol, shikimic acid, and quinic acid. A total content of 25.32 ± 2.65 mg gallic acid equivalent per gram of dry plant (mg GAE/g DW) and of 10.54 ± 0.083 mg rutin equivalents/g of dry plant (mg RE/g DW) were found. The essential oil had D-limonene, α-cadinol, δ-cadinene, 13-epimanool, and δ-3-carene as predominant components. The spruce vegetative buds exhibited significant antioxidant activity (IC50 of 53 μg/mL) and antimicrobial effects against Staphylococcus aureus. Furthermore, concentrations of heavy metals Pb and Cd were below detection limits, suggesting that the material was free from potentially harmful contaminants. The results confirmed the potential of this indigenous species to be used as a source of compounds with pharmacological utilities. [ABSTRACT FROM AUTHOR]

The value and uniqueness of forest ecosystems are determined by their species diversity and biotic resistance to negative environmental impacts. The aim of the study is to determine the species composition, systematic position, trophic specialization, as well as the occurrence and abundance of forest mycobiota with Abies alba in the Pokutsko-Bukovyna Carpathians. The study was conducted in 2019-2023 within the forests of the branches "Kutske Forestry", "Ivano-Frankivsk Forestry" and "Beregomet Forestry" of the State Specialized Enterprise "Forests of Ukraine", as well as the forests of the National Nature Park "Vyzhnytskyi" and the National Nature Park "Hutsulshchyna". Classical mycological identification methods were used in the study. Information from the interactive databases Index Fungorum, MycoBank, and World of Fungi of Ukraine was used to clarify the current systematic position and current names of taxa. It was found that the consortial relationships of the fungal biota of the Pokutsko-Bukovyna Carpathians forests are most closely related to the woody plants Picea abies, Abies alba, and Fagus sylvatica. During the mycological expedition, 54 species of representatives of the kingdom Fungi were identified, 81.5% of which belong to the order Basidiomycota and 18.5% to the order Ascomycota. It was found that the most numerous is the order Polyporales, and the least numerous are the orders Corticiales, Gomphales, Phallales, Pucciniales and Tremellales. It is shown that, according to trophic specialization, representatives of the studied mycobiota of the Pokutsko-Bukovyna Carpathians belong to the following groups: xylotrophic facultative saprotroph, xylotrophic facultative pathogen, xylotrophic obligate saprotroph, obligate pathogen and aboveground saprotroph. It is noted that the most widely represented are saproxylytrophs, which generally develop on dead and fallen wood. Thus, the systemic and structural analysis of the fungal biota of the Pokutsko-Bukovyna Carpathians forests allows for assessing the biocenotic value of fungi as bioindicators of the current state of stands, as well as identifying reference and valuable areas characterized by high biodiversity [ABSTRACT FROM AUTHOR]

Using a unique 8‐year data set (2010–2017) of phloem data, we studied the effect of temperature and precipitation on the phloem anatomy (conduit area, widths of ring, early and late phloem) and xylem‐ring width in two coexisting temperate tree species, Picea abies and Fagus sylvatica, from three contrasting European temperate forest sites. Histometric analyses were performed on microcores taken from tree stems in autumn. We found high interannual variability and sensitivity of phloem anatomy and xylem‐ring widths to precipitation and temperature; however, the responses were species‐ and site‐specific. The contrasting response of xylem and phloem‐ring widths of the same tree species to weather conditions was found at the two Slovenian sites generally well supplied with precipitation, while at the driest Czech site, the influence of weather factors on xylem and phloem ring widths was synchronised. Since widths of mean annual xylem and phloem increments were narrowest at the Czech site, this site is suggested to be most restrictive for the radial growth of both species. By influencing the seasonal patterns of xylem and phloem development, water availability appears to be the most important determinant of tissue‐ and species‐specific responses to local weather conditions. Summary statement: A unique 8‐year data set of phloem and xylem anatomy datashows high sensitivity of phloem traits to precipitation and temperature. The species‐ and site‐specific response to weather factors indicates the ability of trees to adapt phloem structure to function optimally under local conditions. [ABSTRACT FROM AUTHOR]

The checklist serves as an informative method for evaluating the diversity, geography, and ecology of established and reproducing macrofungi. Additionally, considering macrofungi as bioindicator species, their census should be incorporated into efforts to monitor the state of health of ecosystems and directly applied to conservation policies. Between 2019 and 2023, a census of macrofungal species was conducted in Taburno-Camposauro Regional Park (Campania, Italy) across nine distinct habitats. A total of 453 fungal taxa were identified, including several new records for the Campania region. The fungal diversity exhibited significant variations based on the dominant plant species in each habitat. Fagacean tree species and Carpinus spp. shared similar fungal communities. Equally, coniferous tree species displayed a comparable fungal composition. In Abies alba and mixed broad-leaved forests, low levels of ectomycorrhizal taxa were observed alongside a concurrent increase in saprotrophs, indicating a disturbed habitat and a reduction in the Gadgil effect. Notably, lower fungal diversity was documented in the grassland habitat, suggesting the potential implications of wildlife imbalance and excessive grazing. The provided checklist constitutes a valuable resource for local management authorities, providing insights to formulate specific management policies. [ABSTRACT FROM AUTHOR]

This study examined the carbon (C) concentration of the major tree species (Scots pine, Norway spruce, and Birch) in Sweden based on destructively sampled biomass data. The examination was made using single trees and comprised three components: branches with needles, stemwood with bark, and stump with roots. We developed a weighted C concentration estimator accounting for fresh weights of tree components to infer the C concentration at the population level. Significant differences in C concentration (%) were found among species, with the highest in pine (50.671 ± 0.211), followed by spruce (49.518 ± 0.164) and the lowest in birch (49.347 ± 0.241). Additionally, the C concentration varied among tree components, regardless of tree size, growth rate, and site conditions. At the national level, we applied the estimated species- and component-specific C concentration constants to the measured total biomass of the major tree species from the National Forest Inventory. This extrapolation revealed that the average C concentration of major trees across all forestlands in Sweden was approximately 50.012%. These findings have significant implications for accurate C sequestration reporting in the LULUCF sector. [ABSTRACT FROM AUTHOR]

For European silver fir (Abies alba (Mill)), reliable threshold values for the sulfur nutritional status are not available. Because European silver fir is an important coniferous tree species in Central Europe and due to the fact that by reduced S emissions, S is becoming a more and more critical nutrient this knowledge gap should be closed. From the interpretation of the cumulative distribution of sulfur concentrations in first‐year needles, the respective threshold values for the range of normal nutrition as well as the threshold for deficiency could be derived. When knowing these thresholds also the range of harmonic nutrition, which is the range for the optimal relation of two nutrients, could be calculated. As compared to the very few literature data available and compared to the respective values of the two most important European conifers Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), the values derived for S nutrition of European silver fir are very reasonable. With respect to the S nutritional thresholds, European silver fir is very close to the values of the other two conifers, whereas the harmonic range of S in relation to N is a bit shifted to higher values indicating that European silver fir has a slightly higher demand for S (in relation to N). There is a certain time lag between the reduction of SO2 emissions in Europe and the reduction of S concentrations in needles, suggesting that S stored in the soil during periods of high emissions is relevant for S nutrition of trees for a longer period of time. [ABSTRACT FROM AUTHOR]

Forest biomass has become a viable alternative energy source for replacing fossil fuels, particularly after the European Union acknowledged its sustainability status. To reach zero net greenhouse gas emissions by 2045 in Sweden, new efficient methods of biomass extraction, such as geometrical biomass thinnings, are being explored and tested. These machine-based methods involve the extraction of above-ground biomass in narrow, 1–2 m-wide strips between extraction racks. While evidence-based optimization of biomass extraction mostly focuses on time- and cost-efficiency and on stand growth, criteria such as tree diversity are often overlooked. However, with ongoing climate change, tree diversity is crucial to strengthening the resilience and productivity of future forests, which also enhance the provision of ecosystem services and overall biological diversity. Therefore, we studied the effects of different biomass thinning strategies on spatial tree diversity in southern Sweden using nearest-neighbour summary statistics. We found scientific evidence that different geometrical designs of biomass thinning, especially in 1 or 2 m-wide strips, resulted in higher spatial tree diversity compared to conventional biomass thinning. Hence, in mixed conifer-broadleaved forests, biomass thinning in 1 or 2 m-wide strips is recommended for maintaining spatial tree diversity. [ABSTRACT FROM AUTHOR]

In practice, for the manufacture of plywood, the veneer is usually dried to a moisture level suitable for bonding. However, anatomical differences within and between veneer sheets are a significant factor and some of them may contribute to significant differences in moisture content (MC). The novelty of this work was to study the possibility of using wood veneers of different MC in adjacent layers in one structure of plywood panels and how this affects the physical and mechanical properties of the panels. The Norway spruce (Picea abies L. Karst) wood veneers with mean MC approximately of 2%, 5% and 7% and phenol-urea-formaldehyde (PUF) resin were used in the experiments. The five-layers plywood panels were manufactured at the two pressing pressures of 0.8 MPa and 1.2 MPa. There was no significant difference in the bending and bonding properties, but only wood failure as measured on bonding specimens which showed higher average values on specimens manufactured with high pressure during hot pressing. Higher differences in MC of each veneer with constant MC of the veneer stack didn't worse bending and bonding properties of plywood. [ABSTRACT FROM AUTHOR]

The escarpments of sub-horizontally deposited rocks represent regional centres of geomorphological activity whose evolution is controlled by the occurrence of different types of slope processes. Surprisingly, historical landslide activity on escarpments of Cretaceous rocks has not yet been studied in detail at the regional level using precise absolute dating methods. In this study, dendrogeomorphic methods including sparse dating with seasonal accuracy were used to determine the activity of flow-like landslides that model the eastern margin of the Bohemian Cretaceous Basin. Geophysical ERT (electrical resistivity tomography) measurements and grain size analysis of the landslide material revealed high saturation of the landslide body with groundwater and a high content of fine-grained fraction, which potentially slows down the infiltration of water into the landslide body, thus moving mainly in its near-surface part. Dendrogeomorphic dating (of 177 Picea abies (L.) Karst. individuals) revealed 7 years of landslide activity in the five landslides studied. The dated movements appear to have a low-magnitude character as indicated by the structure, intensity and duration of the dated growth disturbances. In addition, the dated movements have the character of secondary post-failure movements within up to three generations of older landslide bodies. Dating with seasonal accuracy specified their occurrence to the period July to August. This study represents the first use of dendrogeomorphic methods to characterise landslide movements in a Cretaceous escarpment setting, providing a new perspective on this globally widespread phenomenon. [ABSTRACT FROM AUTHOR]

Gremmenia abietis (Dearn.) Crous (syn: Phacidium abietis) was originally described in North America to accommodate the species associated with snow blight of Abies and Pseudotsuga spp. In Japan, this species was first observed on the dead needles on Abies sachalinensis and Picea jezoensis var. jezoensis in 1969. However, the identity of Japanese species was unclear due to the lack of molecular data and the absence of anamorph description. In this study, we collected fresh specimens from various conifer species (A. sachalinensis, A. veitchii, Pic. jezoensis var. jezoensis, Pic. jezoensis var. hondoensis, Pinus koraiensis, and Pin. pumila) in Japan and revised the taxonomy based on morphological and phylogenetic analyses. Phylogenetic analyses based on nuc rDNA internal transcribed spacer ITS1-5.8S-ITS2 (ITS), nuc 28S rDNA (28S), and RNA polymerase II second largest subunit (RPB2) regions indicated that the species belongs to Phacidiaceae. Conidiomata formed in vitro produced pyriform, hyaline conidia without mucoid appendage, which distinguished the species from phylogenetically related genera. Consequently, we established Chionobium takahashii to accommodate the snow blight fungus in Japan. Further phylogenetic analyses also indicated that C. takahashii includes several distinct clades corresponding to the host genera (Abies, Picea, Pinus). Morphological differences among those clades were unclear, suggesting that C. takahashii may contain host-specific cryptic species. [ABSTRACT FROM AUTHOR]

The aim of the presented study was to compare the diversity and composition of fungal communities associated with the roots and the rhizosphere soil of P. abies and Larix sp. in mid-age and mature managed forest stands in Lithuania. We also aimed to assess the presence of fungi–host-specific associations, i.e., whether Larix sp. stands could provide habitats for soil fungi currently associated with P. abies. The study sites were 10 Larix sp. and 10 P. abies forest stands in Lithuania. For the study, 100 root samples and 10 organic and 10 mineral soil samples were collected in P. abies stands as well as the same number in Larix sp. stands, and DNA was isolated, amplified using ITS2 rDNA as a marker and subjected to high-throughput sequencing. The results showed that the Shannon diversity index of fungal communities was similar between the two tree species when compared either between root (H = 4.26 P. abies and H = 3.82 Larix sp.), organic soil (H = 5.12 P. abies and H = 5.13 Larix sp.) or mineral soil (H = 4.71 P. abies and H = 4.29 Larix sp.) samples. Multivariate analysis showed that the fungal community composition in the organic and mineral soil samples of both P. abies and Larix sp. were similar, and thus, overlapping. The analysis also showed that the distribution of fungal species was denser in the roots and organic soil but more scattered in mineral soil. However, several fungi in the roots of either P. abies or Larix sp. showed a certain host specificity. [ABSTRACT FROM AUTHOR]

The results of a study of somatic embryogenesis in Norway spruce (Picea abies (L.) H. Karst.), growing in the middle taiga subzone in the Republic of Karelia (Russia), are presented. Immature zygotic embryos were collected from ten clones of plus trees at the Petrozavodsk Seed Orchard and a tree in Petrozavodsk at a sum of effective temperatures from 728 to 1257 degree days (at a base temperature of 5°C). It has been found that it is necessary to use the LM nutrient medium as a substrate for the induction of somatic embryogenesis and proliferation of cell lines and embryos at the development stages from globular to cotyledonary as explants. After 14 months of cultivation, 12 of 26 (56%) cell lines obtained from explants from the Petrozavodsk Seed Orchard and two cell lines of 23 (9%) from a tree in Petrozavodsk were preserved. As a result of the study, maternal genotypes of clones of plus trees of Norway spruce, capable of forming an embryonic suspensor mass, long-term proliferation, and the formation of regenerated plants were identified. [ABSTRACT FROM AUTHOR]

Conifers are long-lived and slow-evolving, thus requiring effective defences against their fast-evolving insect natural enemies. The copy number variation (CNV) of two key acetophenone biosynthesis genes Ugt5/Ugt5b and βglu-1 may provide a plausible mechanism underlying the constitutively variable defence in white spruce (Picea glauca) against its primary defoliator, spruce budworm. This study develops a long-insert sequence capture probe set (Picea_hung_p1.0) for quantifying copy number of βglu-1-like, Ugt5-like genes and single-copy genes on 38 Norway spruce (Picea abies) and 40 P. glauca individuals from eight and nine provenances across Europe and North America respectively. We developed local assemblies (Piabi_c1.0 and Pigla_c.1.0), full-length transcriptomes (PIAB_v1 and PIGL_v1), and gene models to characterise the diversity of βglu-1 and Ugt5 genes. We observed very large copy numbers of βglu-1, with up to 381 copies in a single P. glauca individual. We observed among-provenance CNV of βglu-1 in P. glauca but not P. abies. Ugt5b was predominantly single-copy in both species. This study generates critical hypotheses for testing the emergence and mechanism of extreme CNV, the dosage effect on phenotype, and the varying copy number of genes with the same pathway. We demonstrate new approaches to overcome experimental challenges in genomic research in conifer defences. [ABSTRACT FROM AUTHOR]

Background: Cryopreservation makes it possible to preserve plant biodiversity for thousands of years in ex situ storage. The stepwise dehydration method is a simple and versatile cryopreservation technique based on the vitrification phenomenon. However, the commonly used dimethyl sulfoxide (DMSO) in this cryopreservation technique is considered harmful for plant material, thus alternative methods are needed to be applied. Results: In this study, the possibility of cryopreservation of embryogenic tissues (ETs) of Abies alba x A. numidica and Pinus nigra was investigated. Before freezing, ETs were partially dehydrated in the presence of increasing concentrations of sucrose (from 0.25 to 1.0 M) for 7 days, followed by desiccation of the tissues over silica gel for 2 and 2.5 h, respectively. After these pretreatments, the plant material was frozen in liquid nitrogen (LN; –196 °C). For both coniferous trees the ET survival rate was high and reached 84.4% for A. alba x A. numidica (28 days) and 86.7% for P. nigra (35 days) after recovery of the tissues from liquid nitrogen (LN). The regenerated tissue of A. alba x A. numidica was characterized by more intense growth after storage in LN compared to tissue that had not been cryopreserved (control). The tissue of this tree also undertook relatively rapid growth after thawing from LN. In turn, the ET growth of P. nigra was significantly lower after thawing compared to the other treatment. Conclusions: The present study demonstrated, that the stepwise dehydration method could be successfully applied to the cryostorage of ETs of both studied trees. To the best of our knowledge, this is the first report on ET cryopreservation based on this method for Abies and Pinus genus representatives, which may be the alternative way for efficient, long-term preservation of germplasm in LN. [ABSTRACT FROM AUTHOR]

Nowadays, an increased concern regarding using natural products for their health benefits can be observed. The aim of this study was to assess and compare several phenolic compounds found in 15- to 60-year-old Douglas fir, silver fir, larch, pine, and spruce needle and bark extracts and to evaluate their antioxidant and antimicrobial activities. Spectrophotometric assays were used to determine the total polyphenol content and the antioxidant activity that was assessed by using the DPPH• radical scavenging assay (RSA), the ferric reducing antioxidant power assay (FRAP), and the ABTS•+ radical cation scavenging assay (ABTS). The phytochemical content was determined by using high-performance liquid chromatography, and the antimicrobial activity was determined by assessing the minimal inhibition concentration (MIC). The results of the study show a total polyphenol content of 62.45–109.80 mg GAE/g d.w. and an antioxidant activity of 91.18–99.32% for RSA, 29.16–35.74 µmol TE/g d.w. for FRAP, and 38.23–53.57 µmol TE/g d.w. for ABTS. The greatest quantity of phenolic compound for most of the extracts was for (+)-catechin, and it had values between 165.79 and 5343.27 µg/g d.w. for these samples. The antimicrobial inhibition for all the extracts was the strongest for Staphylococcus aureus (MIC 62.5–125 µg/mL). The extracts analyzed could be used for their bioactive potential after further investigations. [ABSTRACT FROM AUTHOR]

Continuous cover forestry (CCF) has gained interest as an alternative to even-aged management particularly on drained peatland forests. However, relatively little is known about the physiological response of suppressed trees when larger trees are removed as a part of CCF practices. Consequently, studies concentrating on process-level modeling of the response of trees to selection harvesting are also rare. Here, we compared, modeled and measured harvest response of previously suppressed Norway spruce (Picea abies) trees to a selection harvest. We quantified the harvest response by collecting Norway spruce tree-ring samples in a drained peatland forest site and measuring the change in stable carbon and oxygen isotopic ratios of wood formed during 2010–20, including five post-harvest years. The measured isotopic ratios were compared with ecosystem-level process model predictions for |${\kern0em }^{13}$| C discrimination and |${\kern0em }^{18}$| O leaf water enrichment. We found that the model predicted similar but lower harvest response than the measurements. Furthermore, accounting for mesophyll conductance was important for capturing the variation in |${\kern0em }^{13}$| C discrimination. In addition, we performed sensitivity analysis on the model, which suggests that the modeled |${\kern0em }^{13}$| C discrimination is sensitive to parameters related to CO2 transport through stomata to the mesophyll. [ABSTRACT FROM AUTHOR]

This research focuses on increasing wood resistance against UV degradation using trimethoxyphenylsilane as modifying agent and supercritical CO2 as a green solvent and reaction medium. Trimethoxyphenylsilane was successfully grafted on European spruce (Picea abies, H. Karst) and was characterized by SEM-EDX and UV–vis reflectance. SEM-EDX showed the presence of silicium inside the wood cell wall. Increased wood moisture content showed positive effect on weight gain of trimethoxyphenylsilane after treatment. UV resistance of treated wood was evaluated by following the color change during artificial weathering. Modified samples showed improved weathering resistance compared to unmodified wood with a ΔE value around 5 after 260 h. Processing and modifying wood using supercritical CO2 is a promising route to increase wood performances and increase its use as a building material. [ABSTRACT FROM AUTHOR]

The aim of this study was to elucidate how different nursery production methods influence the composition of and relationship between soil and root community levels of Abies alba. In the Międzylesie Forest District, we quantified the responses of samples of both community-level fine roots and surrounding soil to environmental changes evoked by various seedling production methods. Fungi levels were identified based on their ITS 1 region and 5.8 S rDNA component. Analysis was conducted using Illumina SBS technology, and the obtained sequences were compared with reference samples deposited in the UNITE. Chemical analysis of the soil was also performed. Different nursery production methods resulted in a strong decoupling in the responses of fungal community levels between soil and roots. Changes in growth conditions imposed by production methods were significant in determining species composition. We found differences in fungal communities among functional groups of samples. In the soil, the dominant species of mycorrhizal fungi were Tylospora asterophora, Amanita rubescens, and Russula ionochlora. Mycorrhizal fungi in roots included Tuber anniae, Thelephoraceae sp., and Acephala applanata. Specific soil substrate conditions significantly influenced fungal community composition, leading to an increase in abundance of mycorrhizal fungi, specifically T. anniae. [ABSTRACT FROM AUTHOR]

Restoring degraded forest ecosystems is an important element in the ongoing challenge to sustain the integrity and functioning of the biosphere. However, the evaluation of restoration success is hampered by long lead times of management measures in forests. Moreover, forest change is accelerating also in the absence of management because of ongoing climate change. Yet, because a counterfactual is frequently missing, it remains unclear whether restoration measures are aided or impeded by climate change.Here, we analysed the pace and success of forest restoration under climate change, combining field data and simulation modelling. We focused on the management zone of Berchtesgaden National Park (BGNP), Germany, where restoration aims to restore homogeneous Norway spruce (Picea abies) forests to structurally diverse mixed mountain forests. We evaluated three alternative restoration strategies: Two active strategies focused on planting the currently underrepresented silver fir (Abies alba) and European beech (Fagus sylvatica) but differing in the creation of gap‐cuts, and a third passive restoration strategy without interventions. Strategies were simulated with the forest landscape model iLand from 2020 to 2100 under different climate scenarios (historic, RCP 2.6, 4.5, and 8.5).The forests of BGNP developed into structurally diverse and mixed forests under all evaluated management strategies, and differences between active and passive restoration were generally small. While restoration goals for forest structure were largely met by 2100, forest composition remained far from target in all strategies. Climate change aided restoration by significantly increasing the prevalence of silver fir and European beech (+104.2% to +258.6%). Field data on short‐term restoration effects were in line with simulated long‐term trajectories.Synthesis and applications: We here show that forest restoration efforts in Central European mountain forests will likely be accelerated by climate change. Nonetheless, the slow pace of restoration underscores the need for taking action. Our study highlights that active restoration measures such as tree planting can bring the system closer to restoration targets. However, it also demonstrates that passive restoration (no intervention) is a viable option for management, highlighting the need to evaluate restoration measures against the counterfactual of a no intervention strategy. [ABSTRACT FROM AUTHOR]

The present paper deals with the analysis of cross-section surface irregularities after CO2 laser cutting. The surface irregularities of beech (Fagus sylvatica L.), oak (Quercus petraea), and spruce (Picea abies L.) wood were quantified by primary profile parameters using a digital microscope. The arithmetic mean height (Pa), used as the basic parameter, was supplemented by amplitude parameters (Pv, Pp, Pz) and the Psm parameter, through which the shape of the irregularity was specified in more detail. A statistically significant change was demonstrated when changing the values of the feed speed and the power of the CO2 laser. The results of this article confirm that the surface irregularities increased with an increasing laser power and decreasing feed rate. The scanned topographic images also provide a more detailed explanation of the measured P-parameters and point out the risks associated with the evaluation of the cross-section with the primary profile. [ABSTRACT FROM AUTHOR]

Intraspecific macromolecule variation in stemwood, knotwood, and branchwood was studied using analytical pyrolysis with the intention of introducing a rapid working method to assess the variance in lignin content using analytical pyrolysis and highlight variability markers. The study was performed on Picea abies, Abies alba, and Pseudotsuga menziesii. Lignin determined via analytical pyrolysis–GC/MS (Py-lignin) can be used to identify variations in lignin content, compared to using classical Klason lignin values as a reference method for lignin determination, which requires a correction factor. Principal component analysis (PCA) was performed to identify biopolymer pyrolysis product markers for different species, tissues, or heights that could help highlight structural differences. Douglas fir was differentiated from spruce and silver fir in the levoglucosan amount. Guaiacol was more present in spruce wood, and creosol was more present in Douglas fir. Knotwood was structurally close to stemwood in spruce and silver fir, but there was a clear transition between stemwood and branchwood tissue in Douglas fir. Knotwood was differentiated by higher furan compounds. Branchwood was clearly separate from stemwood and knotwood and presented the same markers as compression wood in the form of phenylpropanoid lignins (H-lignin) as well as isoeugenol and vinyl guaiacol, the two most produced lignin pyrolysis products. [ABSTRACT FROM AUTHOR]

The study aimed to compare two substrates, soil and deadwood, for the regeneration of silver fir (Abies alba Mill.) seedlings. Three-year-old fir seedlings growing both on deadwood and in the soil were collected. The examination involved determining the physical, chemical, and biochemical properties of soil and deadwood, as well as assessing the morphology of the roots and the nutrition of seedlings growing on the soil and deadwood. The examined substrates differed in physical, chemical and biochemical properties. It was shown that strongly decomposed fir logs are a good substrate for the growth of fir seedlings, mainly due to the high content of exchangeable cations (especially calcium, magnesium and potassium) and high phosphorus and nitrogen content. The type of substrate had a significant impact on the root morphology of fir seedlings. In our study, the most responsive root traits to differences in growing substrates were specific root area (SRA) and specific root length (SRL). Our analyses did not confirm significant differences in the stoichiometry of C, N and P in the roots and needles of seedlings grown on different substrates. The stoichiometry of roots and needles suggests no limitations in the uptake of nutrients by seedlings growing on deadwood. This study validated that heavily decomposed wood can provide favourable microhabitats for the growth of the young generation of fir. [ABSTRACT FROM AUTHOR]