Search Results (1,071)

Picea koraiensis (Korean spruce) is a boreal tree species of considerable ecological and economic importance in Northeast Asia, particularly within its natural range in China, Russia and the Korean Peninsula. This study investigated spatial variation in key bioclimatic factors and their relationships with terrain gradients to clarify how these variables influence the species’ distribution. Using high-resolution climate data and species-occurrence records, we examined the effects of elevation, slope and aspect on temperature and precipitation patterns across the species’ range. Precipitation-related variables, including bio13, bio14 and bio15, were closely associated with habitat suitability, whereas elevation and slope affected local temperature stability and moisture availability. Higher elevations and steeper slopes generally provided cooler, wetter conditions favorable for P. koraiensis. Climate modelling predicts that suitable habitats will shift northwards and to higher elevations in response to climate change and are likely to contract under high-emission scenarios. Identifying climate refugia and areas with stable bioclimatic conditions provides important insights for conservation prioritization. This study highlights the need for targeted conservation strategies, including protecting identified climate refugia, maintaining or restoring connectivity corridors between suitable habitats, and carefully assessing assisted migration to climatically favorable northern and higher-elevation areas, to support the long-term viability of the species under rapid climate change. Full article

Nonlinear mixed-effects models (NLMMs) provide a flexible framework for modeling repeated-measures trajectories. However, how best to forecast future observations, especially at ages well beyond those represented in the data, remains relatively underexamined. In this study, we develop a Chapman–Richards NLMM with a spatial-power autocorrelation structure for irregularly spaced repeated measures and compare three forecasting strategies: (i) population-averaged forecasts based on the fixed-effects component only; (ii) subject-specific forecasts in which empirical best linear unbiased predictors (EBLUPs) of the random effects are obtained via a first-order Taylor series expansion with an iterative Newton–Raphson update, including the case of new progenies not used in model fitting; and (iii) forecasts that combine the population-averaged prediction with prior repeated measures through the fitted autocorrelation matrix. Forecast accuracy was assessed with progeny-level validation under fully held-out and partially observed scenarios, using root mean square prediction error (RMSPE) and mean absolute error (MAE), and was examined as a function of: (i) the number of available prior measures and (ii) the accuracy of the fixed-effects component of the NLMM. The methods were illustrated with repeated-measures data from hybrid spruce (Picea engelmannii Parry ex Engelmann × Picea glauca (Moench) Voss) progeny trials at three planting sites in British Columbia, Canada, with measurement ages from 2 to 42 years. Subject-specific forecasts had the lowest prediction errors when sufficient prior measures were available and were also the least affected by misspecification of the fixed-effects component. With only two prior measurements, autocorrelation-based forecasts had the lowest or tied-lowest observed errors, although differences among the three approaches were small. Using all measurements taken before age 42, subject-specific forecasts of height at age 42 achieved an RMSPE of 0.50 m. With only two prior measurements, the corresponding RMSPEs were approximately 1.31–1.33 m across the forecasting approaches. Although demonstrated with a single hybrid spruce dataset from three planting sites, the comparison is, in principle, applicable to other repeated-measures settings in which long-horizon predictions are required from short observation histories; broader applicability remains to be confirmed. Full article

Androgenetic alopecia (AGA) is the most common form of hair loss, characterized by the progressive miniaturization of hair follicles driven by dihydrotestosterone (DHT)-mediated androgen receptor signaling. Current pharmacotherapies remain limited in efficacy and are often associated with undesirable side effects. Pungenin, a phenolic glucoside isolated from Picea wilsonii Mast., was investigated for its therapeutic efficacy in DHT-induced AGA model mice in this study. In primary mouse hair follicle cells exposed to DHT, pungenin mitigated cellular injury, restored normal morphology and viability, and significantly reduced the expression of type II 5α-reductase (Srd5α2). Topical treatment with pungenin markedly accelerated hair regeneration, as demonstrated by histological analysis and serum biochemical measurements. Transcriptomic profiling combined with network pharmacology suggested that the protective effects of pungenin are associated with transcriptional regulation of the PI3K/AKT/FoxO/mTOR axis, identifying 25 putative therapeutic targets, with qPCR further confirming the altered expression of key genes within this network. Collectively, these findings demonstrate that pungenin protects hair follicles against DHT-induced injury through suppression of Srd5α2 and transcriptional modulation of the PI3K/AKT/mTOR signaling axis, supporting further preclinical evaluation of pungenin as a potential candidate for AGA management. Full article

Soil fungi play a key role in nutrient cycling and soil organic matter turnover, yet the influence of pedological context on fungal communities across forest types remains insufficiently understood. Here, we combined soil chemical analyses, Fourier-transform infrared spectroscopy (FTIR), and ITS2 metabarcoding to investigate soil properties and fungal communities in temperate mountain beech (Fagus sylvatica L.) and Norway spruce (Picea abies (L.) H. Karst) forests in Italy developed on contrasting geological substrates. Soil horizons were sampled across seasons to characterize the main associations between fungal community structure, inferred functional diversity, and environmental context. Soil chemistry revealed site- and horizon-dependent patterns, particularly in pH, Ca, and P availability, whereas differences related to dominant tree species were comparatively limited. FTIR spectra showed clear variation in organic matter composition among sites, consistent with site- and stand-associated differences in organic matter composition. Fungal community composition was primarily associated with site and soil horizon. Functional guild patterns suggested ectomycorrhizal dominance in Ca-rich soils and greater prevalence of saprotrophs in more acidic soils. Overall, this multi-proxy approach suggests that pedological context was more closely associated with fungal community structure and ecological strategies than with vegetation type or season within the studied stands. These patterns should be interpreted as site-specific and hypothesis-generating because substrate types were not replicated across independent locations. Full article

Potassium silicate is used as an inorganic fire-retardant treatment for wood, but its effect on the short-term thermal response of different species under combined temperature–moisture conditions remains insufficiently described. This study investigated spruce (Picea abies (L.) H. Karst) and beech (Fagus sylvatica L.) wood impregnated with potassium silicate and exposed to temperatures representing drying, mild thermal loading and the onset of thermal degradation. The evaluation included impregnation uptake, moisture content, mass changes, heat-transfer behavior, differential scanning calorimetry (DSC), chemical composition, Fourier-transform infrared spectroscopy (FTIR) of isolated cellulose and color measurements. Spruce showed higher uptake than beech, with an average weight percentage gain (WPG) of 10.5% compared with 3.6%. The treatment increased equilibrium moisture content by 2.6 percentage points in spruce and 1.1 percentage points in beech. Heat-transfer measurements showed that temperature and moisture governed heating: higher target temperatures were reached faster, whereas air-conditioned samples heated more slowly due to water evaporation. At lower temperatures, the direct effect of impregnation on heating time was limited, whereas at higher temperatures the treatment more clearly affected the subsequent degradation response. DSC revealed lower thermal resistance of beech and increased endothermic heat absorption in impregnated samples, particularly spruce. Higher-temperature exposure caused mass loss, hemicellulose degradation, moderate cellulose structure modification and visible color changes, with ΔE* exceeding 52 in impregnated spruce after 210 °C. The elevated-temperature response was governed by wood species, uptake, moisture content and thermal exposure level. Full article

Ips hauseri Reitter is the most important wood-boring pest of natural Tianshan spruce (Picea schrenkiana) forests and is listed as an A2 quarantine pest by the European and Mediterranean Plant Protection Organization (EPPO). Because the beetle is small and cryptic and its immature stages cannot be reliably identified by morphology, a rapid molecular identification method is urgently needed. Here, we targeted the mitochondrial cytochrome c oxidase subunit I (COI) gene, designed a set of I. hauseri-specific LAMP primers, and established a visually interpretable LAMP assay using a WarmStart colorimetric system. The optimal reaction conditions were 63.8 °C for 35 min. The assay amplified only I. hauseri, with no cross-reaction with the related species Pityogenes spessivtsevi, Ips typographus, Ips subelongatus, and Hylurgus ligniperda; its limit of detection was 100 pg of genomic DNA; and it amplified efficiently from adults, larvae, pupae, and a single egg. Positive results could be scored directly by eye from the red-to-yellow colour change in the reaction, requiring no precision instruments at any step. Using a non-destructive alkaline crude-DNA extraction (HotSHOT), the assay also amplified I. hauseri directly from single adults and larvae, confirming its compatibility with a rapid, field-simple sample preparation. The LAMP assay was rapid, specific within the tested panel, and simple. However, broader validation with additional sympatric non-target species and geographically distinct populations of I. hauseri is needed before routine field or quarantine application. Full article

One of the major environmental problems in recent years is the deterioration of atmospheric air quality. Human activity in urban areas leads to the emission of particulate mat-ter containing various chemical components, including toxic heavy metals, which can accumulate in living organisms. The accumulation of pollutants by various species in mountain environments remains insufficiently understood. Therefore, the aim of this study was to assess the potential use of two species commonly co-occurring in mountain habitats—epiphytic lichen Parmelia sulcata Taylor and spruce Picea abies L., H. Karst.—as biomonitors of anthropogenic atmospheric pollution. The study was conducted in the Central Sudetes (Poland), across three site categories characterized by varying degrees of anthropogenic pressure (green, rural and urban areas). The results confirm that Parmelia sulcata can serve as a species reflecting heavy-metal contamination originating from atmospheric deposition, mainly lead, iron, cadmium and chromium, whereas the needles of Picea abies are useful mainly for indicating manganese pollution. No significant effect of anthropogenic pressure on heavy-metal concentrations was found, which is most likely related to specific air circulation in mountain areas that leads to the dispersion of air pollutants and their accumulation by the study species in the higher regions of the Central Sudetes. Full article

Norway spruce (Picea abies L.) growing in mountain forests is a sensitive indicator of environmental change, but its growth response may be strongly modified by local site conditions, which is important for sustainable forest management under climate change. This study examined two spruce populations in the upper montane zone of the Śnieżnik Massif, Eastern Sudetes, southwestern Poland: one growing on a raised bog (Sadzonki—TS) and the other on mineral soil (Owczarnia—OW). Tree-ring width (TRW) chronologies were developed from 59 sampled trees represented by increment cores and stem discs, covering 1781–2023 for TS and 1800–2023 for OW. Annual δ¹³C analysis was performed for a selected TS tree, and decadal wood geochemistry was analyzed for a selected disc. Spruces growing on the raised bog showed tree-ring widths that were less than half those of trees growing on mineral soil. TRW was mainly controlled by summer or spring–summer temperature, while precipitation had a stronger positive effect at the mineral-soil site. δ¹³C showed weak relationships with TRW but negative correlations with mean annual and summer temperature. Elevated concentrations of Na, K, Ca, Mg, Fe, Mn, Cu, Zn, and Pb occurred mainly in 1941–1950 and 1971–1980, indicating the influence of historical air pollution. The contrasting growth trends and health status of the two populations demonstrate that local habitat conditions strongly shape spruce responses to environmental change and should be considered in sustainable mountain forest conservation and adaptation strategies. Full article

Western Siberia is one of the largest high-latitude lowland peatland regions on Earth and stores vast amounts of organic carbon in landscapes where vegetation, hydrology and fire are strongly regulated by permafrost. However, the long-term interactions among fire disturbance, permafrost dynamics, peatland development and forest–mire vegetation change remain insufficiently resolved. Here, we reconstructed regional vegetation dynamics, local mire succession, permafrost evolution and fire activity in the subarctic Pur–Taz interfluve, Western Siberia, during the Early to Middle Holocene from 11.2 to 4.4 cal kyr BP. The study combines pollen, non-pollen palynomorphs, microcharcoal records, principal component analysis and comparison with modern surface-sample analogues. The record documents a transition from Early Holocene larch–birch forest-tundra with no close modern analogue to increasingly heterogeneous forest–mire and shrub-tundra landscapes. After 9.5 cal kyr BP, Betula pubescens declined and Picea obovata pollen increased, with the strongest spruce signal between ca. 5.5 and 4.7 cal kyr BP. However, this pattern did not necessarily reflect a uniform regional expansion of spruce. Integrated fire reconstruction, based on microcharcoal peaks, Gelasinospora-type and declines in Betula pubescens-type pollen, indicates that recurrent fires after 8.0 cal kyr BP preferentially affected well-drained birch–larch uplands, whereas wetter riparian habitats acted as refugia for spruce. This landscape contrast increased the relative contribution of Picea pollen from fire-protected valleys, producing an apparent, partly artefactual spruce expansion signal. Locally, an open lake present at 11.2 cal kyr BP was transformed into a peatland after ca. 9.7 cal kyr BP. Cooling associated with the 8.2 cal kyr BP event promoted permafrost aggradation and polygonal mire initiation, whereas subsequent thaw and subsidence favoured waterlogging and mesotrophic fen development. Repeated alternation between permafrost aggradation, oligotrophication, degradation and renewed waterlogging culminated in polygonal microrelief by 6.1–5.3 cal kyr BP. These results show that Holocene vegetation change in the Pur–Taz interfluve was not controlled by climate alone, but by spatially heterogeneous feedbacks among permafrost state, peatland hydrology, fire disturbance and pollen-source structure. The West Siberian record provides a palaeoecological analogue for anticipating nonlinear vegetation and fire-regime responses in permafrost lowlands under ongoing Arctic warming. Full article

This study investigated microstructural, optical, and thermal changes in spruce wood (Picea abies) exposed to controlled laboratory heating to identify indicators associated with the transition from progressive thermal degradation to the initial char formation. Cubic specimens measuring 20 × 20 × 20 mm were exposed to selected temperatures between 240 and 300 °C under atmospheric conditions, with a 15 min isothermal exposure period. Microstructural changes were evaluated by scanning electron microscopy (SEM) and quantitative tracheid double cell wall measurements, supported by simultaneous thermal analysis (STA) and color and reflectance analyses. Simultaneous thermal analysis (TG/DTG/DSC) was performed on separate specimens from the same wood material to provide complementary thermal evidence. The most pronounced microstructural changes were observed between 250 and 260 °C, including substantial thinning of tracheid cell walls, degradation of bordered pits, increased brittleness, and localized structural collapse. Quantitative measurements showed reductions in double cell wall thickness exceeding 50% at 260 °C. TG/DTG analysis indicated the onset of intensive thermal degradation at 254.2 ± 1.48 °C, while optical measurements showed pronounced darkening and reduced differentiation of reflectance spectra above approximately 260 °C. The combined evaluation of complementary analytical methods indicates that the 250–260 °C interval represents a condition-dependent microstructural transition associated with accelerated thermal degradation and the early development of a charred structure under the applied experimental conditions. These findings provide complementary experimental evidence for interpreting the early stages of wood charring and may support the interpretation and future refinement of heat transfer and pyrolysis models. They complement, rather than replace, the conventional 300 °C engineering char line criterion used in structural fire design. Full article

Standard actuarial methods often fail to accurately price the risk of catastrophic events due to the characteristic low frequency and high severity of such occurrences. To address these limitations, two actuarial solutions that integrate current knowledge of extreme value theory (EVT) with the theory of non-life insurance are proposed. To address the extreme risk, the Gumbel distribution (solution E1) and the chi-squared distribution (solution E2) were applied. The applicability of the proposed insurance models against the risk of windthrow damage was demonstrated on Norway spruce (Picea abies L. Karst.) stands at a national scale within the Slovak Republic. The results reveal a crucial economic relationship between the insurance layers: the higher the reliability and cost of coverage in the primary model, the cheaper the subsequent secondary premium for risk of extreme damage becomes. For both assumed return periods of 20-year and 100-year extreme events, the solution E2 generates lower and more acceptable total insurance premiums. Subsequently, both models address effectively the foundational insurance concept of risk minimization through spatial diversification. Full article

Background: Extreme drought and flood events continuously threaten the stability of forest and crop production. Long-term hydrological records derived from tree-ring anatomical proxies provide critical evidence for revealing historical drought hazard differentiation. Methods: Cell wall thickness chronologies of Betula platyphylla (northern forest) and Picea koraiensis (southern agro-pastoral zone) were developed to reconstruct nearly 300-year annual runoff sequences. Pearson correlation, quadratic regression, wavelet transform and superposed epoch analysis (SEA) were applied to quantify hydrological evolution, periodic signals, large-scale climate forcing and statistical coupling between dry/wet extremes and historical yield reduction records. Results: The northern watershed showed stronger interannual runoff oscillation. Both regions entered persistent low-flow phases post-1950. Pacific Decadal Oscillation (PDO) acted as the dominant driver, while solar radiation exerted weak secondary regulation. Severe drought events corresponded closely to historical forest and grain yield losses, with far higher agricultural vulnerability in the southern agro-pastoral ecotone. Conclusions: This study reconstructed the long-term historical runoff of the Greater Khingan Range from the thickness of the cell wall, analyzed the different impacts of PDO on it, and clarified the differentiated effects of drought and flood on agricultural and forestry production losses and the interrelated impact of land use on hydrology and the value of agricultural output. Full article

Norway spruce (Picea abies [L.] Karst.) is a paleoecologically relevant species in the Northern Hemisphere since the early Holocene. P. abies populations are sensitive to climate fluctuations; Asian treeline species are under nature protection. The thick wax and cuticle layers of spruce needles enhance their durability, making them frequent in glacial lake and peat bog cores. Their phytoliths are easily recognizable in sedimentary material and can be studied in subfossil tissues. The aim of this study is to assess the applicability of characteristic phytoliths from Norway spruce needles in paleoclimate research. We examined phytolith presence as a function of altitude in plant samples from three Carpathian Mountain ranges. Temperature data loggers were deployed at sampling sites to better characterize the thermal background of phytolith formation. Our results show a decreasing trend in phytolith presence with increasing elevation. The phytoliths formed by the transfusion tissue represent a sensitive type, indicating that spruce needle phytolith production responds to microclimatic variation. These findings are worth further investigation and validation. The study also provides a basis for refining the calculation method, contributing to the development of a potential “phytolith thermometer” for paleoclimatic reconstruction. Full article

The objective of this study was to evaluate the antioxidant and antibacterial profiles of Picea orientalis (Oriental spruce) resin extracts collected from three distinct geographical sites (Artvin, Borçka, and Çaykara) within the Eastern Black Sea region of Türkiye. Additionally, it aimed to assess the viability of these extracts as natural antibacterial agents against cariogenic pathogens and to determine their subsequent effect on dental bond strength performance. Quantitative phytochemical analysis of the ethanolic extracts included the determination of total phenolic content, coupled with individual phenolic profiling by HPLC-PDA. The antioxidant potential was assessed through DPPH and FRAP assays. Additionally, the antibacterial activity against a panel of oral and systemic pathogens was evaluated using agar well diffusion. Furthermore, to evaluate mechanical performance, composite bond strengths were tested on 180 dentin specimens using both self-etch and etch-and-rinse adhesive strategies, following cavity pre-treatment with a control, chlorhexidine, or the resin extracts. The results revealed that the resin from the Artvin region exhibited the highest phenolic content, characterized by an abundance of trans-cinnamic, caffeic, and ferulic acids, which correlated with their superior antioxidant capacity. Furthermore, while the extracts demonstrated potent inhibitory effects against Staphylococcus aureus, their antibacterial activity against Streptococcus mutans was found to be comparatively moderate. In bond strength evaluations, the non-aged control group exhibited the highest values (p = 0.000); however, no statistically significant difference was observed between the chlorhexidine and resin extract groups (p > 0.05). Consequently, the phenolic-rich P. orientalis resin represents a promising natural antibacterial alternative for dental applications. Full article

Ips hauseri (Coleoptera: Curculionidae: Scolytinae) is a destructive stem pest of Picea schrenkiana var. tianshanica, and determining its larval instars is essential for monitoring population development and timing control. Healthy spruce logs were deployed to attract ovipositing adults, and 553 larvae were collected through sequential destructive sampling of previously unsampled logs from June to July 2025. Head capsule widths were measured and analysed using kernel density estimation (KDE) and a Gaussian mixture model (GMM), and the classification was biologically validated against the theoretical growth expectation of the Brooks–Dyar rule, together with the Crosby growth-ratio test and linear regression. Head capsule widths showed a clear trimodal distribution corresponding to three instars, with mean widths of 515.82 ± 21.50, 676.01 ± 27.22, and 885.96 ± 38.27 μm for instars I–III. The mean Brooks–Dyar ratio was 1.311, and the natural logarithm of head capsule width was almost perfectly linear with instar number (R² > 0.999; p < 0.001). This study provides the first quantitative evidence that I. hauseri has three larval instars, offering a basis for studying its developmental biology and improving population forecasting and precise management. Full article