Search Results (276)

A previous study demonstrated that spontaneous forest recovery can result in the development of functional mixed forests in post-mining areas. A critical step in this process is the establishment of climax woody species in the understory of pioneer trees. In this case study, we utilise repeated sampling to evaluate the establishment, initial survival, and growth of pedunculate oak (Quercus robur) and European beech (Fagus sylvatica) seedlings, and to newly assess Norway spruce (Picea abies) during unassisted forest recovery on a post-mining site after coal mining near Sokolov in North Bohemia. Detailed mapping of beech and oak seedlings was conducted in 2009 and 2012 (i.e., 14 and 11 years after the site was reclaimed). Now, we have resurveyed these seedlings, which has allowed us to evaluate their survival and growth. We have also mapped spruce seedlings and estimated their age from annual branch whorls. In the original study, most seedlings were found on the northern site near the edge of the post-mining area and the surrounding landscape, which serve as seed sources. Beech shows the best survival and growth on the northern site, where the greatest number of new seedlings also appear. In contrast, oaks demonstrate much higher mortality than beech overall, with the highest mortality observed on the northern site and the highest survival on the southern site, where most of the new seedlings also appeared. Interestingly, however, surviving oaks grew faster on the northern site. Across microtopography, seedlings of all three tree species were most frequent on the slopes of micro-undulations. Beech individuals were taller in depressions, whereas oaks did not consistently demonstrate a size advantage across microhabitats. Spruce colonised vigorously and was the most abundant of the three species across microhabitats. Age-frequency analyses suggest an annual mortality rate of 3%–9%. Browsing damage was observed on 19% of beech seedlings and 9% of oak seedlings. The study shows that pioneer tree stands are suitable nursing sites for studied climax tree species, which can colonise these sites several kilometres away from mature trees, and their establishment involves a complex interplay between distance to seed source and local microclimatic conditions. Our resurvey indicates that later successional stages may increasingly be shaped by shade-tolerant beech and spruce under the developing canopy. Full article

In order to expand the raw material base of lignocellulosic briquettes, and due to the shortage of wood materials, the use of lignocellulosic residues from the agricultural sector (such as hemp waste) became the main objective of this research. In order to state the significant differences between these briquettes, the lignocellulosic briquettes were obtained from hemp core waste and oak sawdust on the same hydraulic briquetting installation. The main properties of the two categories of briquettes were determined; we obtained a bulk density of about 450 kg/m³ for hemp core waste and 530 kg/m³ for oak sawdust. Also, the calorific values of the two categories of materials were about 18.2 MJ/kg and 17.5 MJ/kg, high calorific values (HCV) for hemp core waste/oak sawdust, and the calcined ash content was 5.8% for hemp and 0.8% for oak sawdust briquettes. As a general conclusion, through their physical–mechanical, calorific and chemical properties, it can be stated that the remains of the core obtained when obtaining hemp fibers can be used successfully to make fuel briquettes. Full article

Afforestation of post-agricultural land is one of the most important challenges of modern forestry, posed by economic demand and climate protection. Unfortunately, stands introduced on such degraded soils are not sustainable and their productive value is limited. The present study tested the effects of two substances—Humac and Alginite—on the community structure of mesostigmatid mites colonizing plots overgrown by Platanus × acerifolia (Aiton) Willd, also comparing them with the mite communities of arable field and 64-year-old stands of Pinus sylvestris L. and Quercus robur L. growing on post-agricultural land. A total of 306 mite individuals were recorded, belonging to 45 taxa and 14 families. The results indicate a moderately positive effect of Humac fertilization on the mite communities studied. A similar impact has not been demonstrated for Alginite. In contrast, all parameters studied (density, species richness and diversity of mite communities) reached the highest values in the P. sylvestris stand. Humac application harmonizes Mesostigmata mite community structures between young and older stands and may be considered a beneficial practice for the afforestation of former agricultural land. Full article

Oak forests provide critical ecosystem services, but are being increasingly exposed to climate variability, drought, and insect outbreaks that threaten their long-term resilience. This study aims to integrate structural canopy indicators with climate-derived indices to detect early-warning signals of decline in temperate oak stands. We monitored eight Forest Management Units in western Romania between 2017 and 2021, combining field-based assessments of crown morphology, vitality traits, defoliation, and epicormic shoot frequency with hydroclimatic indices such as the Forest Aridity Index. Results revealed strong spatial and temporal variability: several stands showed advanced canopy deterioration characterized by increased defoliation, dead branches, and epicormic resprouting, while others maintained stable conditions, suggesting resilience and suitability as reference sites. Insect defoliators, particularly Geometridae, contributed additional stress, but generally at subcritical levels. By synthesizing these metrics into conceptual models and a risk scorecard, we identified the causal pathways linking climatic anomalies and biotic stressors to structural decline. The findings demonstrate that combining structural and climatic indicators offers a transferable framework for forest health monitoring, providing robust early-warning tools to guide adaptive silviculture and resilience-based management. Beyond the Romanian context, this integrative approach supports sustainability goals by strengthening conservation strategies for temperate forests under global change. Full article

Xylella fastidiosa was first detected in Portugal in 2019 in Lavandula dentata. In response, the national plant health authorities promptly established a Demarcated Zone in the affected area and implemented a series of eradication and control measures, including the systematic removal and destruction of infected and host plants. This study analyzes the economic and operational impacts of these eradication efforts in the northern region of Portugal, with a focus on Demarcated Zones such as the Porto Metropolitan Area, Sabrosa, Alijó, Baião, Mirandela, Mirandela II, and Bougado between 2019 and June 2023. During this period, about 412,500 plants were uprooted. The majority were Pteridium aquilinum (bracken fern), with 360,324 individuals (87.3%), reflecting its wide distribution and the large area affected. Olea europaea (olive tree) was the second most common species removed, with 7024 plants (1.7%), highlighting its economic relevance. Other notable species included Quercus robur (3511; 0.85%), Pelargonium graveolens (3509; 0.85%), and Rosa spp. (1106; 0.27%). Overall, destruction costs were estimated at about EUR 1.04 million, with replanting costs of roughly EUR 6.81 million. In parallel, prospection activities—conducted to detect early signs of infection and monitor disease spread—generated expenses of roughly EUR 5.94 million. While prospecting represents a significant financial investment, the results show that it is considerably more cost-effective than large-scale eradication. Prospection enables early detection and containment, preventing the widespread destruction of vegetation and minimizing disruption to agricultural production, biodiversity, and local communities. Importantly, our findings reveal a sharp decline in confirmed cases in the initial outbreak area—the Porto Demarcated Zone—from 124 cases in 2019 to just 5 in 2023, indicating the effectiveness of the eradication and monitoring measures implemented. However, the presence of 20 active Demarcated Zones across the country as of 2023 highlights the continued risk of spread and the need for sustained vigilance. The complexity of managing Xylella fastidiosa across ecologically and logistically diverse territories justifies the high costs associated with surveillance and targeted interventions. This study reinforces the strategic value of prospection as a proactive and sustainable tool for plant health management. Effective surveillance requires the integration of advanced methodologies aligned with the phenological stages of host plants and the biological cycle of vectors. Targeting high-risk locations, optimizing sample numbers, ensuring diagnostic accuracy, and maintaining continuous training for field teams are critical for improving efficiency and reducing costs. Ultimately, the findings underscore the need to refine and adapt monitoring and eradication strategies to contain the pathogen, safeguard agricultural systems, and prevent Xylella fastidiosa from becoming endemic in Portugal. Full article

Galls of the Cynipidae, such as the Knopper gall, are abnormal plant outgrowths induced by insect activity. These structures not only protect the developing larvae but also alter the biochemical properties of host plant tissues. In this study, we report the green synthesis of silver nanoparticles (AgNPs) using ethanolic extracts of Quercus robur Knopper galls. AgNPs were synthesized via reduction of AgNO₃ and characterized using ATR-FTIR analysis, UV-Vis spectrophotometry, powder X-ray diffraction (PXRD), and transmission electron microscopy (TEM). The UV-Vis analysis showed a strong surface plasmon resonance (SPR) peak at 418 nm. A face-centered cubic (fcc) crystalline structure with an average crystallite size of about 12 nm was verified by PXRD patterns. TEM imaging revealed well-dispersed spherical nanoparticles, consistent with the size obtained via PXRD. ATR-FTIR analysis indicated the involvement of polyphenolic and protein-related functional groups in reduction and stabilization. The synthesized AgNPs exhibited strong growth inhibition capacity against B. subtilis and S. aureus, and moderate capacity against E. coli and P. aeruginosa. These findings highlight the potential of Knopper gall extract as a sustainable source for the eco-friendly synthesis of biologically active nanoparticles. Full article

Using the RadSawSim simulator for radial sawing, a simulation of the radial sawing technique was used to saw Pedunculata oak (Quercus robur L.) logs. Simulation was implemented with a view to producing as many radially sawn boards as possible and took into account the influences of increasing volume yield, lumber value yield, and log-value yield. The methods that were analyzed were live sawing and radial sawing of third sections, fourth sections, fifth sections, and sixth sections of the log. Live sawing achieved the best results of volume yield during simulation, which was followed by radial sawing into the third, fourth, fifth, and sixth sections. The difference in volume yield with live sawing compared to the radial-sawing method is very large for logs up to a diameter of 45 cm. It becomes smaller when the log diameter is greater than 45 cm. A comparison of the radial method shows that the share of radially sawn boards and lumber value yield increased when the number of log sections during sawing simulation increased. If log-value yield is assumed to be the main criterion, and given the conditions used in this simulation, there is no justified reason to saw logs using the radial technique when the diameter is less than 45 cm. The live sawing technique is more efficient for these diameters of logs, and, therefore, the radial sawing technique is more efficient for logs with a diameter greater than 45 cm. Full article

Alien woody plants (AWPs) increasingly threaten biodiversity in China’s national nature reserves, with climate change expected to intensify these risks. We used species distribution modeling (MaxEnt) and spatial prioritization (Zonation) to assess invasion risk for 251 AWP species across 479 national nature reserves under current and future climate scenarios (SSP245 and SSP585). Spatial prioritization revealed current hotspots in southern tropical–subtropical national nature reserves (e.g., Hainan, Fujian, Yunnan provinces), with significant northward and westward expansion projected under warming. A total of 71 species—such as Quercus robur, Salix alba, and Robinia pseudoacacia—pose consistently high risks, while some others (e.g., Ficus benghalensis) may become emerging threats under future conditions. These range shifts are driven by thermal constraint relaxation and longer growing seasons. To mitigate future impacts, we recommend region-specific strategies: containment and seed-source control in southern national nature reserves, and early detection and monitoring in northern and western regions. Our findings provide a spatially explicit framework for climate-informed invasive species management in protected areas. Full article

Acute Oak Decline (AOD) is a progressive disease affecting oaks across Europe and is increasingly recognised as a threat to the health of forests and urban trees. While the occurrence of this disease has been documented in forest ecosystems, its presence in urban landscapes is still poorly understood. In this study, the occurrence of AOD-associated bacteria (Brenneria goodwinii, Gibbsiella quercinecans, Rahnella victoriana, Lonsdalea quercina) was investigated in Quercus robur and Q. rubra growing in urban areas of Wrocław, Poland. Multiplex real-time PCR analyses confirmed the pathogens in 11 trees, with B. goodwinii being the most common species. Importantly, we provide the first confirmed detection of B. goodwinii in Q. rubra under urban conditions, possibly the first such detection in Europe. The results show the occurrence of AOD-associated pathogens in urban environments, suggesting that such habitats may provide favourable conditions for their occurrence. However, further investigations, including epidemiological and spatial analyses, are needed to clarify whether urban areas contribute to the persistence or spread of these pathogens. Beyond local documentation, our results emphasise the need to include urban ecosystems in AOD surveillance and highlight potential pathways for pathogen adaptation and spread in cities. This work provides new insights into the ecology of AOD in anthropogenically modified habitats and has direct implications for urban tree health monitoring, biodiversity conservation, and the development of integrated management strategies. Full article

Forest ecosystems undergo seasonal shifts in bacterial and fungal communities, but little is known about the specific microbiota associated with Quercus robur–Boletus edulis systems. This study represents the first examination of seasonal changes in soil microbiota in pedunculate oak habitats in Galicia (NW Spain) and their relationship with Boletus edulis and Boletus reticulatus mycelium prevalence and concentration. Soil microbiota richness, diversity, and composition, as well as seasonal variation in Boletus mycelium, were assessed using DNA metabarcoding and qPCR, respectively. Sampling was conducted in autumn at two 30–40-year-old Q. robur stands. Bacterial communities were dominated by Acidobacteria (34%) and Proteobacteria (33%), with Acidobacterium (12%), Paludibaculum (9%), and Edaphobacter (7%) identified as most abundant. Fungal communities were primarily Basidiomycota (93%), led by Russula (46%). For both bacteria and fungi, the highest OTU richness was observed in September, followed by a significant decrease in October and a partial recovery in November. Boletus species were found to exhibit positive correlations with specific bacteria (e.g., Massilia, Rhizobium) and fungi (e.g., Amanita, Clavaria, Inocybe, Scleroderma, Suillus and Mortierella), suggesting a potential influence of these microbes on mycelium development. This study provides novel insights into the seasonal dynamics of soil microbiota and their potential role in Boletus ecology, thereby advancing understanding of host–microbe interactions in temperate forests. Full article

Crown defoliation in trees is one of the indicators of forest tree vitality, and a primary criterion for selecting trees for sanitary felling. In Croatia, the selection of trees for sanitary felling includes all dead trees and those with crown defoliation greater than 60% (defoliation class 3a); in the past, the threshold for marking trees for sanitary felling was above 80% (class 3b). The aim of this study was to analyze tree mortality in pedunculate oak (Quercus robur), silver fir (Abies alba), and European beech (Fagus sylvatica), as well as crown regeneration, i.e., the reduction in defoliation. The analysis included a total of 7975 trees, comprising 1182 silver fir, 4221 European beech, and 2572 pedunculate oak trees, covering the period from 1998 to 2023. The mortality rate was 7.2% for silver fir, 2.16% for beech, and 9.6% for oak. The percentage of trees that regenerated their crowns or reduced defoliation to below 60% was 17.01% for fir, 4.33% for beech, and 12.51% for oak. Considering the proportion of silver fir and pedunculate oak trees whose defoliation decreased to below 60%, a defoliation threshold greater than 80% would be a more appropriate criterion for sanitary felling, except for European beech trees, for which there is a minimal difference between the recovery rates in classes 3a and 3b. Full article

In the context of intensifying climate change, dendroclimatic research provides insight into tree responses to environmental variability. This study assessed relationships between temperature, precipitation, and radial growth of four major forest species in Central Europe: Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) H. Karst), pedunculate oak (Quercus robur L.), and black alder (Alnus glutinosa (L.) Gaertn.). Analyses were conducted at three independent sites to account for local variability and enhance robustness. We tested three hypotheses: (1) replication improves reliability in dendrochronological studies, (2) multi-species analysis strengthens interpretation of climate–growth relationships, and (3) black alder exhibits distinct precipitation sensitivity. Results showed species- and site-specific responses. The first hypothesis was supported, as replication enhanced the robustness of climate–growth signals in Scots pine, Norway spruce, and pedunculate oak showed broadly consistent responses, while black alder maintained its distinct pattern. Scots pine responded strongly to summer rainfall (June–August, including July of the previous year), Norway spruce to summer rainfall (June–July of the current and previous year), and pedunculate oak to summer rainfall (June–July, with additional effects in August). Black alder exhibited positive correlations with winter precipitation (December–January of the previous year) and negative with summer rainfall (May, June, August; September–November of the previous year), suggesting moisture-related stress. Temperature sensitivity occurred in winter and early spring (December–April, especially February–March) for most species, except black alder, which also responded positively to summer temperatures (May, July–September). These findings highlight the importance of species traits and site conditions in dendroclimatic studies and support replicated multi-species approaches to guide adaptive forest management under climate change. Full article

The processing of freshly cut fruits and vegetables represents an important niche for implementing circular economy principles, particularly through the reuse of washing water. This is especially relevant as post-wash water is often treated as wastewater and discarded without reuse. One promising research avenue is the use of plant-derived extracts in water sanitation processes. Their antimicrobial properties offer a natural alternative to conventional disinfectants while reducing the formation of harmful disinfection by-products. The aim of this study was to evaluate the effectiveness of different filter bed configurations in removing pathogens from water. These configurations included a hydrogel saturated with natural plant extracts, an ion exchange resin layer, and an activated carbon layer. The most effective composite was also tested using real process water from a fruit washing line. The test materials included concentrated extracts from oak bark (Quercus robur), willow (Salix alba), birch (Betula pendula), raspberry shoots (Rubus idaeus), tea leaves (Camellia sinensis), and linden flowers (Tilia cordata), all immobilized in hydrogel, along with activated carbon and ion-exchange resin. Water samples were artificially inoculated with six opportunistic pathogens and collected process water was also used. Samples were analyzed microbiologically at six time intervals. The composite filter (hydrogel–resin–carbon) achieved a reduction of over 2 log₁₀ in heavily inoculated water (~10⁸ CFU mL⁻¹) and maintained at least a 1 log₁₀ reduction in real process effluents. The proposed solution supports blue water footprint reduction strategies (as the system aims to decrease the demand for freshwater resources through the reuse of treated wastewater) and aligns with the principles of green processing. Full article

In the context of climate change and the increasing ecological importance of pedunculate oak (Quercus robur L.) in European forests, sustainable regeneration strategies are essential for ensuring long-term forest resilience. This study investigates how different conditions of regeneration sites, namely areas under pine canopies, gaps (openings within the pine stand), inter-gap area (open zone surrounding the pine gaps), and clear-cut area (zone where trees were completely removed), affect the early growth performance of artificially regenerated oak stands in Central Europe. Seedling height, root collar diameter, sturdiness quotient (SQ), and light availability (via hemispherical photography) were assessed. The most favorable growth occurred in gaps and under-canopy sites, where light intensity ranged from 44% to 57%, and seedlings reached mean heights of 148.7 cm and 143.4 cm, respectively. In contrast, seedlings in clear-cut and inter-gap areas exhibited lower growth and higher SQ values, suggesting lower seedling stability. In these areas, the average seedling height was 127.2 cm in clear-cut opening and 137.9 cm in inter-gap area. These sites also had the highest light intensity, amounting to 100% and 89.85% of total incident radiation, respectively. Growth performance was also affected by cardinal direction, except within gaps. This study highlights the importance of microsite selection in oak regeneration and demonstrates how optimizing light conditions can enhance reforestation success and climate resilience. These findings contribute to sustainable forest management practices aimed at supporting adaptive strategies in temperate ecosystems facing climate change. Full article

Oak wood is a popular construction material in Europe. In the course of its service life, this wood is subject to structural changes resulting from the environmental conditions to which it is exposed, in addition to the effects of aging. Samples of naturally occurring historic European oak (Quercus robur L.) were obtained from foundation piles that were utilized to reinforce the riverbanks in Poland, the Vistula River basin, dating to the 2nd century, as well as from a 14th-century settlement on the river in Slupsk. Reference wood was also obtained from contemporary harvesting operations in the vicinity of Slupsk, Poland. The presence of structural changes resulting from partial wood degradation was confirmed through the utilization of FTIR spectroscopy analysis, SEM with BSD microscopy, and chromatic parameters. The differences in the color of historic and reference wood were significant (based on Kruskal–Wallis test = 46.38, where p < 0.001). The results of chemical analysis showed an increase in the proportion of lignin and a decrease in carbohydrate components for the old wood. A higher degree of change in lignin content was observed in historic wood (32–38%) compared to the fresh wood sample (25%). Our study showed that the collected data can be applied to the preparation database of heritage wood materials. Full article