Search Results (96)

Carbon sequestration is considered one of the key factors for sustainable development. The marshes of Aniva Bay (Sakhalin Island) are ecosystems currently undergoing intense natural carbon accumulation (450–930 g∙C∙m⁻²∙year⁻¹) 2–4 times higher than the average speed for similar ecosystems, making this area highly promising for the implementation of “carbon farms.” Carbon sequestration could be accelerated by installing structures on mudflats that capture suspended organic matter from tidal waters. A model experiment was conducted to assess the suitability and biocompatibility of logging waste from coniferous species (Picea ajanensis, Larix leptolepis, Abies sachalinensis) for such structures by simulating their immersion in seawater. The content of phenols and tannins in the resulting water extracts was determined, and the composition of water-soluble substances was analyzed by GC-MS. Extract toxicity was investigated using the halophilic test organism Artemia salina. The experiments revealed the release of tannins in concentrations of up to 14 mg/L, which is nearly 1.5 times the maximum permissible concentration (MPC) and could potentially negatively impact the coastal ecosystem. Furthermore, the concentration of tannins leached from L. leptolepis bark exceeded the MPC by a factor of 5.5. A critical finding is the presence of highly toxic compounds in wood waste, for which targeted analysis is absent in state regulatory documents for hazard assessment. Specifically, immersion of A. sachalinensis wood led to the leaching of juvabione into saltwater at concentrations causing 100% mortality in Artemia salina. Based on the results, the most promising species for the terraformation of mudflats is the use of P. ajanensis logging waste. Full article

Forest decline in genus Abies has been increasingly associated with drought, warming, pollution, and biotic disturbances. However, the importance of these drivers and the degree to which drought–bark beetles’ interactions have been studied in Abies remain insufficiently documented. This review aimed to identify the main reported causes of decline in Abies species worldwide and to assess the current state of knowledge on the drought–bark beetles’ interaction, with special attention to sacred fir (Abies religiosa) because of its ecological importance in Mexico and its role as a winter habitat for the monarch butterfly (Danaus plexippus). We reviewed 237 articles indexed in Scopus and complemented this analysis with bibliometric indicators and keyword co-occurrence maps generated using the Bibliometrix R package (version 5.4.1) and VOSviewer (version 1.6.12). The main causes of decline were drought, pollution, and rising temperatures, affecting 41 taxa in 28 countries. Although drought has been reported throughout the study period (1977–2026), publications linking drought and warming to Abies decline have increased markedly during the last 15 years. Bibliometric results indicate that drought–bark beetles’ interactions have been extensively studied in Pinus and Picea, whereas comparable evidence for Abies remains limited. Future management should integrate monitoring, stand-density regulation, pest surveillance, and climate-adaptation strategies implemented by forest managers, conservation agencies, and local communities. Full article

The by-products of the wood-processing industry are still predominantly used for energy generation, despite being a rich source of high-value phenolic compounds. This review focuses on the valorization of bark from economically crucial European tree species. Based on an extensive literature survey, three deciduous species (Fagus sylvatica, Quercus robur/petraea, Carpinus betulus) and three coniferous species (Pinus sylvestris, Picea abies, Abies alba) were selected on the basis of their distribution in the European Union, their industrial relevance, and the composition and bioactivity of their extractive phenolic fractions. Conventional and nonconventional extraction techniques are briefly compared, with particular emphasis on deep eutectic solvents (DESs) as emerging green media for the selective isolation of phenolics from bark and other lignocellulosic residues. DESs are typically renewable, nontoxic, biodegradable, and nonflammable, and their tunable composition allows them to be tailored to specific target compounds. The literature data demonstrate that DES-based extractions can provide phenolic-rich extracts with high antioxidant and antimicrobial activities and, in some cases, can outperform conventional solvents. Finally, the potential applications of bark-derived phenolic extracts in the pharmaceutical, agricultural, food, polymer processing, and cultural heritage sectors are outlined. The review also identifies knowledge gaps in DES selection, extract purification, and solvent recovery, highlighting future research needs for integrating DESs into sustainable wood-biomass biorefineries. Full article

This paper examines the energy potential of silver fir (Abies alba Mill) and Norway spruce (Picea abies (L.) Karst) trees across three tree crown defoliation degrees (TCDDs): healthy, severely defoliated (61–99%) and dead. The study was conducted in the area of the Forest Administration Delnice, Management Unit »Milanov vrh«, in the Republic of Croatia. Field measurements were conducted on 83 silver fir trees and 114 Norway spruce trees to determine the mass of live and dead branches per tree and to collect samples of wood, bark, main live and dead branches, and side live and dead branches (in total, 813) for further laboratory analyses. Further, differences in wood basic density, moisture content, ash content, net calorific value, and carbon, hydrogen, nitrogen, and sulfur content across TCDD classes were also determined. For both tree species, wood basic density across TCDDs decreased as follows: severely defoliated trees > healthy trees > dead trees. Regression analyses showed that the largest masses of branches occurred on healthy silver fir trees (R² = 0.48), followed by severely defoliated (R² = 0.41) and dead trees (R² = 0.46). The same trend in determined total branch mass per tree was observed for Norway spruce trees, where the coefficient of determination was highest for dead trees (R² = 0.72), followed by severely defoliated (R² = 0.69) and healthy (R² = 0.61) trees. A negative correlation between moisture content and TCDD class was observed for wood, bark, and live branches. The highest net calorific value was found for side live branches for both researched species, and only the net calorific value of side live branches of Norway spruce was statistically significantly different across TCDD classes. Overall, this study showed a negative impact of TCDD on the amount of available tree residues (branches) that could be utilized as a solid biofuel. Furthermore, the results of the laboratory analyses were ambiguous, increasing the complexity and heterogeneity of the wood material and underscoring the need for further investigation. Full article

Bark beetle infestations and other natural disturbances have increasingly affected Norway spruce (Picea abies (L.) Karst.) forests across Europe resulting in devaluation and decreased applicability of woody biomass of such trees. The aim of this research was to investigate the extractive content of bark beetle-attacked and dead wind-damaged Norway spruce trees relative to healthy trees, in order to assess their potential for extractives recovery. After harvesting, three discs were dissected along the stem height of each tree, and samples of sapwood, heartwood, knots, and bark were collected. Sequential extraction of the samples was performed using cyclohexane and acetone–water mixture in an accelerated solvent extractor. Lipophilic and hydrophilic extractives were determined gravimetrically, while total phenols and proanthocyanidins were measured by UV–Vis spectrophotometry. Results showed that knotwood contained the highest amounts of hydrophilic extractives and total phenols among investigated tissues. Knots of healthy trees contained the highest amount of hydrophilic extractives (52.4% w w⁻¹), while knots of dead wind-damaged trees contained significantly higher content of total phenols (8.8% w w⁻¹). The total phenols in bark beetle-attacked and healthy trees were 7.1% w w⁻¹ and 7.2% w w⁻¹, respectively. The sapwood and heartwood of dead wind-damaged trees had higher content of hydrophilic extractives (3.4% and 2.3% w w⁻¹) than healthy and bark beetle-attacked trees. Bark from healthy trees contained more total phenols (2.7% w w⁻¹) than bark of bark beetle-attacked trees, while proanthocyanidin contents in bark were comparable among three groups of trees. Our findings revealed that woody biomass from bark beetle-attacked and dead wind-damaged Norway spruce trees contains significant levels of phenolics, indicating high potential for extracting valuable compounds in biorefineries. Full article

Tree-related microhabitats (TreMs) are small features on living or dead trees that offer habitat, shelter, breeding sites, or food for many organisms, making them useful indicators of forest-dwelling species. Despite increasing research on TreMs in Europe, most published studies have focused on temperate regions, leaving a relative paucity of data from hemiboreal forests. In our research, we aimed to fill the knowledge gap, offering insight into the occurrence patterns and factors influencing TreM diversity in the hemiboreal region. We analyzed data from the National Forest Inventory in Latvia, comprising information on 168,839 trees across 5653 sample plots. The most common TreMs were bark loss (6.1% of trees), bryophytes (2.6%), and perennial polypores (2.6%). TreMs occurred more frequently on deciduous than on coniferous trees, on larger trees (diameter at breast height more than 60 cm), and on dead trees compared to living ones. Forest type and signs of recent cutting also had significant effects on TreM richness at both the tree and plot scales, whereas forest protection status was significant only at the plot scale. TreMs such as buttress-root concavities and ivy or liana cover, which are common in temperate Europe, had a low relative occurrence in our study. The occurrence of specific TreM forms was strongly tree-species dependent: exudates were much more common on live Picea abies (4.0%) than on other species, whereas Populus tremula had a higher occurrence of fruiting bodies of saproxylic fungi and slime moulds (2.0%). The highest occurrence of crown deadwood was observed on Quercus robur. Overall, dead trees play a particularly important role, providing both a higher total number of TreMs and certain TreM types more frequently. Given their high TreM richness, dead and large trees represent important structural components supporting biodiversity in hemiboreal forests. Full article

Norway spruce (Picea abies (L.) Karst.) is experiencing large-scale decline across Central Europe, with climate warming and bark beetle (Ips typographus L.) outbreaks as primary drivers. In lowland Białowieża Forest, Poland, spruce occupies a range of habitats that differ in their suitability for long-term persistence. We hypothesized that climate change accelerates spruce decline by reducing resilience in suboptimal habitats and increasing susceptibility to bark beetle outbreaks, with long-term persistence limited to optimal hydrological sites. To address this, we analysed spruce share from 1902–2018, its distribution across suitable versus unsuitable habitats, and long-term climate records in relation to outbreaks. Historical maps, forest site classifications, and meteorological data were used to calculate hydro-climatic indices (HTC, SPEI-12, Selyaninov), and outbreak relationships were tested using Welch’s t-test and point-biserial correlation, including lag effects. Spruce share increased from 12% in 1902 to 27% in 2015 and then declined to 9% by 2018. In 2015, 75% of spruce-dominated stands occurred in unsuitable habitats. Bark beetle outbreaks were significantly associated with drought, with outbreak years showing lower precipitation (–121 mm), reduced Selyaninov k (mean 1.40 vs. 1.61), and more negative SPEI-12 values (–0.48 vs. 0.07) compared to non-outbreak years (p < 0.05). One-year lag analysis indicated drought as both a predisposing and triggering factor. These findings highlight the interaction of habitat suitability and drought as a key driver of spruce decline, supporting adaptive management strategies that retain spruce in optimal habitats while converting suboptimal stands to more drought-tolerant species. Full article

The European spruce bark beetle, Ips typographus (Linnaeus, 1758), poses a significant threat to Picea abies (Linnaeus) Karsten, 1881 forests, with outbreaks often exacerbated by abiotic disturbances like the 2018 Vaia windstorm in the Italian Alps. Pheromone-baited traps are widely used for control, yet their overall efficacy and potential side effects, particularly the incidental capture of non-target insects, remain debated. This study aimed to comprehensively assess the presence and composition of non-target insects in I. typographus pheromone traps, used for both mass-trapping and monitoring, in the affected Alpine regions. We took into account single monitoring traps (dry collection) and three-trap cross configurations for mass-trapping (with preservative liquid), collecting and morphologically identifying insect by-catch. Our results revealed a non-target proportion (excluding bark beetles) significantly higher in mass-trapping (4.15%) compared to monitoring (1.00%), with approximately half being natural enemies of bark beetles. Crucially, we report that bark beetle parasitoids were repeatedly caught, with Tomicobia seitneri (Ruschka, 1924) (the third most abundant non-target species) particularly well represented, and Ropalophorus clavicornis (Wesmaël, 1835) also detected, which is noteworthy given its ecological role despite its lower numbers. Our findings underscore the significant, previously underreported, capture of beneficial parasitoids and highlight the need for careful consideration of non-target catches in I. typographus pest management strategies. Full article

Softwood bark and twigs represent by-products of forest supply chains rich in extractable bioactive compounds. This study aimed at evaluating the bioactive molecules of hydrodynamic cavitation (HC) based extracts of bark and twigs from different conifer plants and exploring their antioxidant capacity. Samples of Picea abies twigs (RAR) and bark (CAR) and Abies alba twigs (SFT) underwent extraction using a pilot-scale Venturi reactor HC device. The freeze-dried extracts were characterized for the antioxidant capacity, through both in vitro and ex vivo assays, the antimicrobial activity, and the content of phenolics and free amino acids by UHPLC-ESI-MS/MS. HC-based aqueous extracts were obtained quickly and with low energy consumption. We found 10 phenolic acids, nine flavonols, three flavan-3-ols, five flavanones, three procyanidins, two stilbenoids, and 10 other phenolic compounds. Moreover, eight essential and seven dispensable amino acids were found. The principal component analysis showed clear discrimination among the three extracts. The CAR extract showed antimicrobial activity. The SFT extract showed the higher anthocyanins content and antioxidant activity, both through in vitro and ex vivo methods. These preliminary results confirm that by-products of Picea abies and Abies alba are rich in bioactive compounds and antioxidant activities, suggesting potential applications in the nutraceutical and pharmaceutical fields. Full article

In recent years, many spruce (Picea abies (L.) H. Karst., Pinaceae) forests have been severely affected by bark beetle (Ips typographus L., Coleoptera: Curculionidae) outbreaks in the Southern Alps, but their ecological impacts remain poorly studied. We analyzed the distribution, ecological, and floristic–vegetational characteristics of forests recently affected by the bark beetle in the upper basin of the Oglio River (Northern Italy) and developed a MaxEnt model to map forests with a bioclimate more prone to severe insect attacks in the coming decades. The results showed that the spruce forests affected by the bark beetle are located exclusively in the submountain and mountain belts (below 1600 m a.s.l.) and that 85% of them are found in areas with high annual solar radiation (>3500 MJ m⁻²). The predictive model for areas susceptible to severe bark beetle attacks proved highly accurate (AUC = 0.91) and was primarily defined by the mean temperature of the dry winter quarter (contribution: 80.1%), with values between −2.5 and 2.5 °C being particularly suitable for the pest. According to the model, more than 58% of the current spruce forests in the study area will exhibit high susceptibility (probability > 0.7) to severe bark beetle attacks by 2080. The floristic–vegetational and ecological analysis of plant communities of 11 bark beetle-affected areas indicated that more thermophilic and significantly different forest communities (in both floristic and physiognomic terms) are expected to develop compared to those of pre-disturbance. Furthermore, the high coverage of spruce snags/standing dead trees appears to accelerate plant succession, enabling the establishment of mature forest communities in a shorter time frame. Full article

Heavy metals (HMs) from industrial pollution are bioaccumulated in plant tissues, but we lack information on their spatial variability in forest ecosystems. Picea abies L. needles, bark, and litter were collected at 17 sites along a 1000-m-wide altitudinal gradient in southern Romania to measure concentrations of mineral nutrients, non-toxic metals, and toxic metals. Isotopic ratios (^206/207Pb, ^87/86Sr) were used to infer contamination origins. We found significant differences in needle versus bark and litter elements’ concentrations, indicating that needles are sensitive biomarkers in tracking air pollution. We found high Fe, Mn, Zn, and Cu concentrations, which can be involved in the low Na, Mg, and P content in needles. The mole ratios indicate a negative relationship with As concentrations in needles. Several environmental health and ecological risk assessment indices document that Cd levels can represent a moderate risk for most sites. Our study shows that P. abies presented an elevated bioaccumulation potential for Fe, Zn, Cu, Ni, and Cr, respectively, and it only absorbed Na, Sr, Cd, and Li. The methodology and results presented herein may serve as a reference for future studies and provide a foundation to develop management strategies to mitigate heavy metal pollution in forest ecosystems. Full article

Tree bark plays a crucial role in the distribution of rainfall within forest ecosystems, particularly through its impact on stemflow. To gain a comprehensive understanding of how bark controls stemflow, it is essential to identify all factors affecting bark water storage capacity, as this determines the onset of stemflow during rainfall events. Our study analyzed how the position of bark on the stem and the altitude above sea level impact bulk density, water storage capacity, and the time required for bark saturation. We conducted research on Norway spruce bark collected at four altitudes: 400, 550, 700, and 1150 m asl. Our findings revealed that bark from the 400 m altitude had a bulk density that was approximately 24.5% greater than that from higher altitudes. Additionally, the water absorption time for bark from 1150 m was over 68% longer than that for bark from other altitudes. The longest absorption time (about 6.4 days) was observed in the bottom part of the trees, while the shortest (about 4.4 days) was in the top part of the trees. We also observed that the bark water storage capacity increased from the base to the top of the trees and with increasing altitudes. Specifically, the water storage capacity of bark taken from 400 m was approximately 33% lower than that from 1150 m. These findings highlight the significance of stem height position and altitude as key determinants of bark water storage capacity. Full article

In general, bark serves a protective role for trees and is genetically determined. The quantification of bark based on biometric characteristics is linked to studies on the distribution of forest species across the globe and vegetation fires. In Romania, on the other hand, the improvement of the wood traceability system requires an increase in the accuracy of the estimation of the biometric characteristics of bark and, implicitly, of the volume of wood under the bark. The aim of this study was to develop more precise models for predicting bark thickness along the stem of three key Romanian species, taking into account a comprehensive range of models and stem sections, including those with a diameter over bark smaller than 8 cm, which have been excluded in previous studies. The study is based on two datasets, one containing the national measurements of three commercially valuable forest species, i.e., Norway spruce (Picea abies (L.) Karst), European beech (Fagus sylvatica L.), and pedunculate oak (Quercus robur L.) from 12,186 trees, and a second dataset containing the measurements from 61 logs of the same species at a specific forest site. A set of seven double bark thickness (DBT) estimation models with stem diameter over bark (DOB), DOB and total tree height (H), DOB and relative height along the stem (h/H), and diameter over bark at breast height (DBH) and DOB as predictors were used. The DBT models were evaluated using the coefficient of determination (R²), mean absolute error (MAE), root mean squared error (RMSE), the Akaike information criterion (AIC), and the Bayesian information criterion (BIC). This led to the selection of two more accurate models, Model 2 (based on a third-degree polynomial) and Model 3 (based on a logarithmic function), with DOB as the predictor. Relative double bark thickness (RDBT) and proportion of bark area (PBA) were also estimated using a sixth-degree polynomial and relative height as a predictor variable after stratifying the data by DBH classes to reduce variability. The results of this study indicate that there is a need to complete the database, for all three forest species of commercial value in Romania especially for large trees with DBH greater than 60–70 cm. The models obtained for PBA are of great use to the industry and the economy, in particular in the context of the traceability of wood. This is due to the fact that PBA can be equated with the proportion of bark volume (PBV), which describes the variation in the proportion of bark in the volume of the wood assortments along the stem. For a given DBH, PBA and PBV demonstrate minimal variability in sections from the tree’s base to a relative height of 0.6; however, a pronounced increase is observed at crown level in sections above relative heights of 0.8. Full article

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. Full article

Purpose: This study employed a Life Cycle Assessment (LCA) methodology to evaluate the environmental impacts of a novel plant cell-based biomanufacturing process for producing plant natural product ingredients. The primary purpose was to assess the relative sustainability of the process and to provide insights into potential areas of improvement in the biomanufacturing process. Method: The LCA method used an MS Excel (Ver. 2407) -based approach with a cradle-to-gate system boundary covering raw material sourcing (A1), raw material transportation (A2), and product extract manufacturing (A3) stages. Energy use and material inventory data are presented for different unit operations, and environmental impact factors were obtained from the Ecoinvent database. The study included a Material Circularity Index (MCI) calculation to assess the circularity of the biomanufacturing process for the production of saponin emulsifiers that are normally extracted from the woody tissue of the Chilean soapbark tree (Quillaja saponaria). Comparative analyses were performed against a wild-harvest approach for plant tannin extraction from spruce (Picea abies) tree bark. Key Results: The environmental impact assessment focused on determining relative Global Warming Potential (GWP), Acidification Potential (AP), Freshwater Eutrophication (FE), Particulate Matter Formation (PMF), and Ozone Depletion Potential (ODP). Results indicated that the extract manufacturing stage (A3) contributed significantly to adverse environmental impacts, with varying levels of effects based on the energy source used. Comparative analysis with the wild harvest approach highlights the lower environmental impact of the alternative biomanufacturing process. The biomanufacturing process showed a 23% reduction in GWP, AP, and FE and a 25% reduction in PMF and ODP relative to the wild harvest approach. However, the MCI for the biomanufacturing process was estimated to be 0.186, indicating a low material circularity. Conclusions: The results revealed that the extract manufacturing stage, particularly energy consumption, significantly influences the relative environmental impacts of the alternative production processes. Different energy sources exhibit varying effects, with renewable energy sources showing lower environmental impacts. The Material Circularity Index indicated a low circularity for the biomanufacturing process, suggesting opportunities for improvement, such as incorporating recycled or reused materials. Compared with the tannin extraction process, the plant cell-based biomanufacturing process demonstrated lower environmental impacts, emphasising the importance of sustainable practices and the use of renewable energy sources in future plant natural product sourcing. Recommendations include implementing more sustainable practices, optimising raw material choices, and extending product life spans to enhance circularity and overall environmental benefits. Full article