Mycelium-based composites (MBCs) are bio-based materials with insulation potential; however, moisture sensitivity remains a limitation. This study investigated the water-related characteristics of mycelium and MBCs, focusing on moisture sorption, water uptake and dimensional stability. Mycelium from nine basidiomycete species showed sigmoidal sorption isotherms with minor interspecies differences at moderate RH but divergence above 80% RH. Values at 95% RH were indicative because equilibrium was not reached within 24 h. Three species, Daedaleopsis confragosa, Ganoderma sessile and Trametes versicolor, were selected for composite fabrication using beech wood particles and a beech-wood/spent-coffee-grounds mixture. Composite density ranged from 165 to 207 kg·m−3 and depended on substrate formulation. At 90% RH, equilibrium moisture content reached 21–22% for wood-based composites and 25–27% for composites containing spent-coffee-grounds, with thickness swelling of 5.5–6.6%. Water uptake was slower from surfaces exposed to air for longer periods and was consistent with the presence of a denser mycelial layer, although sequential testing may have influenced the differences. Composites including spent coffee grounds had lower short-term and 14-day water absorption under the test conditions. Moisture interactions differed between substrate formulations and were associated with fungal surface characteristics, including mycelial skin development, emphasising that interior use requires moisture control and protection from prolonged high humidity.

The fire and thermal behavior of European beech (Fagus sylvatica L.) and silver birch (Betula pendula L.) woods were comparatively evaluated after being modified by thermal treatment (200 °C), acetylation, and one-sided surface charring. A small-flame ignition test (EN ISO 11925-2), gross heat of combustion via bomb calorimetry (EN ISO 1716), and thermo-gravimetric analysis (TG/DTG) were used for assessment. Thermal modification resulted in moderate mass loss (~3% to 4%), while acetylation achieved high weight percentage gain (>20%) and the strongest reduction in equilibrium moisture content; surface charring had only a negligible effect on bulk moisture properties. While none of the applied modifications altered the Euroclass-related reaction-to-fire classification, statistically significant differences in early-stage flame spread were observed. Acetylated wood exhibited increased flame spread, whereas surface-charred specimens showed a pronounced reduction, particularly for beech. All modified materials displayed higher gross heat of combustion compared with reference wood, reflecting increased carbon-rich constituents; however, this increase did not directly correspond to improved fire performance. TGA revealed similar degradation behavior for reference and thermally modified wood, whereas acetylated and surface-charred materials exhibited fundamentally different thermal responses because of chemical substitution and polysaccharide degradation with carbon-rich char formation, respectively. The study highlighted surface charring as an effective modification for reducing flame spread and demonstrates the necessity of combining complementary fire-testing methods to capture modification-specific fire behavior.

Blue rings (BRs) are wood anatomy anomalies that present great potential in identifying cold spells during the growing season. In this study, we investigated the effect of temperature anomalies on the occurrence of two types of BR in Pinus sylvestris at its northern distribution limit in Norway. Of the 3,508 individual tree rings from 1727 to 2022 analysed, we identified 206 BRs from a span of 85 years, the oldest formed in 1730. We distinguished two types of BR: Type A with normal earlywood and latewood ending with a thin blue layer; and Type B with the entire latewood zone replaced by earlywood-like tracheids. Our results demonstrate that the two types have a common climatic trigger – a cool spring and autumn. However, Type A is more linked to tree-ring width, whereas Type B is associated more closely with tree ontogeny and local environmental constraints. Although we observed the formation of BRs even in old trees, we found that they formed more frequently in young specimens. We showed that while the short-term cyclical drivers of Type A remained persistent, the climatic or environmental drivers associated with Type B gradually diminished under climate change. Our study demonstrates that the differentiation of BRs into types can contribute to a better understanding of their driving factors; however, detailed intra-annual phenological and xylogenetic monitoring will be crucial to achieve further insights.

The cultural landscape in Central Europe has been greatly influenced by long-term human activity. Expansive, intensively farmed agricultural areas generate numerous adverse environmental impacts and do not adequately reflect the challenges of climate change and biodiversity loss. Agroforestry represents a renewed, or perhaps more accurately, a rediscovered approach to help mitigate negative anthropogenic pressure and impact on the environment and landscape. Historically a common feature, its tradition was eroded during the twentieth century, necessitating policy-driven efforts for its revival. The establishment of agroforestry systems (AFS) in the landscape of the Czech Republic was made possible relatively recently with the support of the Common Agricultural Policy (CAP). New legislation and government regulations have been adopted for implementation, which are being changed and amended over time. This article examines the evolution and current state of the legal and regulatory framework governing agroforestry in the Czech Republic. It investigates the principal legislative acts, the influence of the CAP, requirements for establishing and maintaining AFS, and their interplay with nature protection laws. The article describes the potential benefits of agroforestry systems in the landscape in the context of establishing green infrastructure and also describes the shortcomings and requirements (establishment and maintenance AFS) of the current legislative framework in the Czech Republic. This insight can be also useful for lawmakers and experts when introducing new legislation in individual EU Member States or in countries outside Europe. Agroforestry, as part of the green infrastructure in the landscape, has a significant opportunity to restore natural functions and stability in human-fragmented and modified landscapes. Each tree planted contributes a host of positive ecological, economic, and social benefits, the effects of which extend far beyond immediate human timescales.

Mycelium-based biocomposites (MBC) offer a sustainable alternative to synthetic materials due to their biodegradability and low environmental impact. This study examined the structural and mechanical properties of mycelium films produced from nine fungal species representing monomitic, dimitic, and trimitic hyphal systems. These species were selected following preliminary screening of 21 strains for growth characteristics and mechanical performance. Growth rates varied significantly, with Irpex lacteus exhibiting the fastest growth (8 mm/day), while Fomes fomentarius and Daedaleopsis confragosa grew more slowly but exhibited superior mechanical strength. Tensile testing identified D. confragosa as the strongest fungus (6.51 MPa), followed by F. fomentarius, although considerable variability was noted. Ganoderma spp. and Trametes spp. showed moderate to low tensile strength. No consistent correlation was found between mycelium density and tensile strength, nor did chitin content alone explain mechanical performance. For instance, I. lacteus had the highest chitin content but weak tensile properties. Scanning electron microscopy revealed differences in hyphal diameter, density, and cell wall structure, indicating that factors such as glucan-chitin interactions and hyphal morphology influence mechanical behavior. These findings highlight the potential of less investigated fungal species in advancing MBC development.

The aim of this work was to investigate the fire resistance of silver fir (Abies alba L.) and European ash (Fraxinus excelsior) boards charred using the traditional yakisugi method and to compare the results with the fire resistance of non-charred boards as a reference and exploit its potential as a material with fire protection properties. After the boards were surface-charred on one side, specimens with different char thicknesses, resulting from their different position in the chimney, were selected from each wood species and subjected to analysis. Specimens with dimensions of 250 × 90 mm underwent a small flame test, those of 220 × 170 mm received indirect flame exposure by constant heat flux radiation from an infra-red emitter and those of 600 × 600 mm were subjected to a fire resistance test according to EN 1363-1:2020. The results of the small flame tests showed statistically significant fire resistance enhancement of specimens with 6 and 3 mm char-layer thickness in fir and ash wood, respectively, and a 110% and 75% improvement when compared to reference specimens. The constant heat flux radiation tests did not reveal any significant differences between the reference and charred specimens. The up-scaled fire resistance test, in which an assembled panel was exposed to flame, also indicated significant improvement. The reference burn-through time of fir and ash specimens was improved significantly with increasing char layer thickness, resulting in 10%–26% of fire resistance improvement for fir and 5%–12% for ash wood specimens. These results, based on the tests performed, suggest that the one-sided surface-charring of wood can enhance its fire resistance; however, this was mostly achieved in boards with the thickest char layer in both wood species studied and not all fire resistance indicators were considered. Further in-depth studies are required to better understand the complex behaviour of charred wood in response to fire.

Sitka spruce has been one of the most planted tree species in Iceland since the mid-twentieth century. Here, we use different dendrochronological methods to identify the controlling climatic factors of its growth and possible changes in their influence over time. We develop annually resolved and absolutely dated measurements of tree-ring width (TRW) from 21 trees and oxygen (delta 18O) and carbon (delta 13C) stable isotopes from six trees to evaluate growth trends and climate sensitivity in Iceland's Hallormsstaour National Forest over the past 54 years (1965-2018). Warmer and wetter summers in the last few decades have resulted in significantly increasing radial growth. While TRW and delta 13C reflect strong July-August temperature signals, with the highest correlation for July, delta 18O is mainly controlled by the temperature in March. The occurrence of negative pointer years in TRW decreases with increasing temperature in July but increases with excessive precipitation in August. Our study shows great continued potential for Sitka spruce cultivation in Iceland.

Wood modification (by thermal or chemical treatment) helps to improve the dimensional stability of wood and enhance its resistance to biological agents. Beech wood is non-durable and exposure in exterior settings dramatically shortens its service life. To determine the full potential of beech wood for advanced applications, a better understanding of the chemical changes induced by modification is needed. Two chemical treatments (acetylation and melamine formaldehyde resin impregnation) and three thermal treatments (heating to 180, 200 and 220 degrees C) were performed on beech wood. The modification effect was examined based on (i) molecular changes in functional groups by Fourier-transform infrared spectroscopy (ATR-FTIR); (ii) extractive content; and (iii) pH changes. Moreover, the explanation of these changes was supported by the FTIR-analysis of isolated main wood components (cellulose, holocellulose and lignin) from the modified wood. The high temperatures applied to samples during thermal modification promoted the deacetylation and degradation of hemicelluloses. Hemicelluloses were targeted also by acetic anhydride and melamine resin, the bonding of which was confirmed by FTIR analysis. The formation of fewer methylene bridges affected the properties of the melamine network. This observation suggests the need to determine optimal curing conditions in future research, to reduce melamine-wood hydrophilicity.

Human development and induced activities significantly affect the natural functioning of ecosystems and hence landscape connectivity. Ecological corridors are essential for maintaining structural as well as functional connectivity in cultural landscapes for wildlife, while providing interchange between core areas. In two pilot areas in the north-western and eastern part of Austria, ecological corridors were delineated using a geographic information system (GIS). The pilot areas are key to preserving ecological connectivity and are located along important international migration corridors (Bohemian Forest-Northern Alps corridor, Alpine-Carpathian corridor). Both areas are situated in highly human-altered and therefore dissected as well as fragmented landscapes. A one-year monitoring campaign using camera traps was carried out at selected locations along proposed ecological corridors in the cultural landscape and at wildlife crossings structures (WCSs) at intersections with road infrastructure. The monitoring was focused on mammals with a total of 18 species being observed. The most abundant species were roe deer, European hare and wild boar. European otter, European beaver, golden jackal and wildcat have only rarely been observed. Mammal species richness was positively correlated with the presence of vegetation cover and the coefficient of ecological stability (CES). The insights obtained can be used for recommendations and support in planning the planting of vegetation (use of grasslands, scattered and continuous woody vegetation, agroforestry systems) on the sites and in the vicinity of ecological corridors. The green bridges (wildlife overpasses) were used more frequently as well as by a larger number of mammal species compared to other studied WCSs showing characteristics that are less favourable for animals. The effectiveness of WCSs is mainly influenced by human activities, resulting in the recommendation to limit them on WCSs located along the routes of ecological corridors. We point out that actual wildlife migration corridors are likely to differ from designated data-driven ecological corridors generated by spatially explicit models, because these generally do not take into account all factors relating to the effectiveness of corridors. Our results suggest, that the application of the concept of functional connectivity is able to enhance the quality of ecological corridor designations, since usually they are based only on the concept of structural connectivity. For this reason, further studies are needed to help understanding factors and their specificities influencing the interplay between structural and functional connectivity of ecological corridors.

The Arctic is one of the regions most sensitive to global warming, for which climate and environmental proxy archives are largely insufficient. Arctic driftwood provides a unique resource for research into the circumpolar entanglements of terrestrial, coastal and marine factors and processes – past, present, future. Here, first dendrochronological and wood anatomical insights into 639 Arctic driftwood samples are presented. Samples were collected across northern Norway (n =430) and north-western Iceland (n =209) in 2022. The overall potentials and limitations of Arctic driftwood to improve tree-ring chronologies from the boreal forest, and to reconstruct changes in sea ice extent and ocean current dynamics are discussed. Finally, the role driftwood has possibly played for Arctic settlements in the past hundreds of years is examined.

Seven European universities and research institutions from four countries agreed to collaborate on the ASFORCLIC - HORIZON 2020 project to support the ambitious goals of raising the leading institution's MENDELU research profile and strengthening its research excellence in the highly demanding field of assessing the impact of global climate change on forests and the bio-based sector. The ASFORCLIC consortium evaluates possible risk factors, predicts their evolution, and develops adaption strategies for future applications to monitor the impact of global climate change on central European forestry, particularly Czech forestry. Facing the unprecedented challenge of implementing a mobility project during the COVID-19 pandemic, the consortium used strategic approaches and augmented offerings, including successful literature seminars, writing workshops, and advanced data evaluation training largely realized through virtual platforms.

Various crosslinking agents can be added to the formulations of natural-based adhesives for wood bonding in order to achieve better durability and higher strength of the formed joints. In the present study, the effect of hexamethylenediamine (HMDA) addition on the performance of liquefied wood (LW) adhesive for wood bonding is investigated. Differential scanning calorimetry showed the improved thermal stability and crosslinking of the LW adhesive with HMDA. The intensified presence of amide linkages (C-N bonds) was found in LW+HMDA with attenuated total reflection Fourier transform infrared spectroscopy. Analysis of the bonded joints using an automated bonding evaluation system showed that a higher press temperature resulted in stronger bonds for both types of adhesives. Moreover, the addition of HMDA to LW adhesive improved the bond strength of the joints and accelerated the crosslinking of the adhesive. However, with a tensile shear strength of (6.76 +/- 2.16) N x mm(-2) (for LW) and (6.89 +/- 2.10) N x mm(-2) (for LW+HMDA), both adhesives were found to be unsuitable for interior non-structural use. In addition, the acidity of LW resulted in relatively high wood failure (70%) in the adhesive joints tested. Improved crosslinking of LW with HMDA was reflected in improved resistance of LW+HMDA adhesive joints to water degradation. In conclusion, HMDA is a promising additive for improving the adhesive performance of LW adhesives.

Degradation by wood-rotting fungi has been studied in Lignamon and beech wood modified by the Lignamon process. Different treatments that are used during Lignamon process were applied: gaseous ammonia treatment, densification (20 and 40% compression ratio) and heat treatment (180 degrees C). These specimens were exposed to Trametes versicolor and Coniophora puteana for 16 weeks and the mass loss was evaluated. Changes in chemical structure, nitrogen content and pH caused by individual treatments or by fungal activity were also determined. The wood nitrogen content increased after ammonia treatment (1.0%) and was the highest in Lignamon (1.4%), its release during water leaching was very slow. The chemical analysis of wood revealed slight changes in the polysaccharide and lignin content in wood treated with ammonia. Bonded nitrogen was in the form of amides, which were partially thermally degraded by heat treatment. Neither densification nor heat treatment led to better resistance of wood against fungi, while ammonia treatment significantly restricted mass losses (C. puteana 2.5%; T. versicolor 7.5%) compared to untreated wood (both about 30%). Lignamon showed the best fungi resistance (mass loss < 5%), which was probably caused by the combined effect of hemicellulose degradation, an increased nitrogen content, and wood densification.

Silver fir (Abies alba L.) wood samples were charred on one surface using an enhanced version of the traditional Japanese Yakisugi method. The 15 charred boards obtained from five charring chimneys were divided into three different zones and investigated for their physical properties. The density profile, water absorption after 24 h of water submersion, and Brinell hardness were analyzed. In general, the temperature-time regime, which causes inside surface carbonization, was more evident at the bottom than at the top of the chimney. The density profile of the specimens revealed that the surface charring treatment decreased the surface density of the wood significantly. A gradient was visible from 383 kg/m² at the bottom to 424 kg/m² at the top. Water absorption measurements showed that a thicker carbonized layer could take up more water as a result of increased porosity. While 3,684 g/m² were absorbed at the bottom, the top accounted for only 2,533 g/m². Furthermore, with increasing thickness of the charred layer, the hardness gradually decreased. The average of the charred specimens reached only 3.2% of the hardness of the uncharred back side of the specimens.

Specimens of European beech wood (Fagus sylvatica L.) charred at 250 °C (4 min), 300 °C (2 min), and 350 °C (1 min) in combination with linseed oil coating were studied. The influence of the surface charring process and artificial weathering on surface discoloration, water absorption, and decay resistance were analyzed. Discoloration analysis showed a decrease in all parameters L*, a*, and b* due to the charring process. Coating with linseed oil caused a decrease in the L* parameter. An influence on parameters a* and b* was also demonstrated. As a result of the artificial weathering, the L* parameter increased in almost all groups. The group charred at 350 °C showed a decrease in L*. The parameters a* and b* were also affected. The effect of oil coating on discoloration during artificial weathering was negligible. The average water absorption of uncoated charred specimens decreased more than 50%. Damage due to artificial weathering disrupted the effect of the charring process. The effect of oil coating decreased depending on the length of partial immersion. Surface charring and oil impregnation slightly reduced the loss of beech wood mass caused by T. versicolor and P. placenta but could not fully protect the wood.

Forest fires are becoming a serious concern in Central European countries such as Austria (AT) and the Czech Republic (CZ). Mapping fire ignition probabilities across countries can be a useful tool for fire risk mitigation. This study was conducted to: (i) evaluate the contribution of the variables obtained from open-source datasets (i.e., MODIS, OpenStreetMap, and WorldClim) for modeling fire ignition probability at the country level; and (ii) investigate how well the Random Forest (RF) method performs from one country to another. The importance of the predictors was evaluated using the Gini impurity method, and RF was evaluated using the ROC-AUC and confusion matrix. The most important variables were the topographic wetness index in the AT model and slope in the CZ model. The AUC values in the validation sets were 0.848 (AT model) and 0.717 (CZ model). When the respective models were applied to the entire dataset, they achieved 82.5% (AT model) and 66.4% (CZ model) accuracy. Cross-comparison revealed that the CZ model may be successfully applied to the AT dataset (AUC = 0.808, Acc = 82.5%), while the AT model showed poor explanatory power when applied to the CZ dataset (AUC = 0.582, Acc = 13.6%). Our study provides insights into the effect of the accuracy and completeness of open-source data on the reliability of national-level forest fire probability assessment.

The aim of this work was to better understand the ignition method of timber charring in order to improve the industrial process. Three silver fir boards were tied together to make a triangular prism, which acted as a chimney. To start the charring process, the traditional Yakisugi method uses an ignitor paper ball. This ignitor paper ball was in this research replaced with a gas burner. The gas burner supplies the required energy in an even level and provides airflow in the upward direction. The surface temperature of the samples increased from 10 to 500 °C in approximately 40 to 80 s at all recorded positions, which is considerably faster than when using a traditional method. The thickness of the charred layer and the resulting cupping effect were investigated as an indicator of the quality of the process. The charred layer produced by the gas burner method was not as thick as was achieved with the traditional method, which can be attributed to a shorter charring time. Approximately half the specimens showed cupping to the charred side, which may be related not only to a shorter charring time than previous studies, but also to the annual ring orientation of the timber. Further research should be performed on the charred layer thickness and cupping to define all relevant parameters.

Abstract The wood-water interactions of modified beech wood (Fagus sylvatica L.) were studied. Specimens were thermally modified at 180 (TM1), 200 (TM2) and 220 °C (TM3), acetylated (Acet), and melamine formaldehyde (MF) resin (Mel) modified. Afterwards, the water vapour characteristics, i.e. water vapour sorption isotherms, equilibrium moisture content (EMC), dimensional stability of specimens conditioned at 30, 65 and 90% RH and liquid water characteristics, i.e. water absorption, maximum moisture content (MC), leachability and swelling kinetics, were determined and the results compared with reference (Ref) specimens. From the results, it is evident that the scale of wood-water interactions was highly dependent on the thermal modification temperature and type of chemical modification. The water vapour isotherms of thermally modified wood decreased, whereas more severe treatment exhibited more distinct reduction. The EMC values of the Mel and TM1 specimens decreased only at high RH, whereas the most significant decrease, within the whole range of observation, was found in the Acet group. The maximum MC reduction was achieved by acetylation. As a consequence of swelling reduction, dimensional stability expressed as anti-swelling efficiency (ASE) was considerably improved. A relatively high initial linear-phase swelling rate was found for the Ref specimens, whereas modified wood exhibited comparatively slow and gradual swelling.

Tree rings provide valuable insight into past environmental changes. This study aimed to evaluate perturbations in tree ring width (TRW) and δ15N alongside soil acidity and nutrient availability gradients caused by the contrasting legacy of air pollution (nitrogen [N] and sulphur [S] deposition) and tree species (European beech, Silver fir and Norway spruce). We found consistent declines of tree ring δ15N, which were temporarily unrelated to the changes in the TRW. The rate of δ15N change in tree rings was related to the contemporary foliar carbon (C) to phosphorus (P) ratio. This observation suggested that the long-term accumulation of 15N depleted N in tree rings, likely mediated by retained N from deposition, was restricted primarily to stands with currently higher P availability. The shifts observed in tree-ring δ15N and TRW suggest that acidic air pollution rather than changes in stand productivity determined alteration of N and C cycles. Stable N isotopes in tree rings provided helpful information on the trajectory of the N cycle over the last century with direct consequences for a better understanding of future interactions among N, P and C cycles in terrestrial ecosystems.

Driftwood supply was a pivotal factor for the Norse expansion in medieval times and still exhibits an essential resource for Arctic settlements. The physical causes and societal consequences of long-term changes in the distribution of Arctic driftwood are, however, poorly understood. Here, we use dendrochronology to reconstruct the age and origin of 289 driftwood samples that were collected at remote shorelines in northeast Iceland. Based on 240 reference tree-ring width chronologies from the boreal forest zone, and an overall provenance success of 73%, we show that most of the driftwood is pine and larch from the Yenisei catchment in central Siberia. Our study reveals an abrupt decline in the amount of driftwood reaching Iceland since the 1980s, which is corroborated by the experience of local farmers and fishers. Despite the direct and indirect effects of changes in both, logging activity across Siberia as well as Arctic Ocean currents, the predicted amount of sea-ice loss under anthropogenic global warming is likely to terminate Iceland's driftwood supply by 2060 CE.