Search Results (35)

Black alder (Alnus glutinosa) is widely used to reclaim nutrient-poor post-mining soils, yet how adverse conditions affect seasonal foliar macronutrient dynamics and resorption remains unclear. We compared seasonal changes in leaf C, N, P, K, S, Ca, and Mg concentrations in A. glutinosa on an extremely nutrient-poor sandy Technosol versus a fertile Gleysol during the growing season. Seasonal macronutrient patterns were similar at both sites: N and S concentrations remained stable, P and K declined toward autumn, and Ca and Mg increased. Trees growing on Technosol exhibited lower late-season K concentrations, indicating K limitation under poor, drought-prone conditions, whereas foliar N and P differed minimally between sites. Resorption was element-specific rather than site-specific: P exhibited the highest resorption efficiency, while K resorption was higher on the Technosol. Neither Ca nor Mg was significantly resorbed. These findings confirm black alder’s suitability for post-mining reclamation due to robust N and P acquisition, while highlighting potassium as the primary limiting nutrient on sandy mine soils. Full article

Black alder (Alnus glutinosa (L.) Gaertn.) wood is characterized by rapid and frequently non-uniform color changes after felling and during hydrothermal processing. These changes are largely associated with extractive compounds, among which oregonin, a phenolic diarylheptanoid glycoside, has been identified as a precursor of the characteristic orange-red coloration. However, information on the thermal stability of oregonin remains limited. This study investigated the effect of temperature and exposure time on oregonin content in black alder bark extract. Aliquots of the extract were exposed to isothermal conditions of 30, 40, 50, and 60 °C for up to 24 h. In a separate trial, a treatment at 98 °C was conducted to simulate the temperature conditions associated with wood saturated water steaming at atmospheric pressure. Oregonin concentration was determined using reversed-phase high-performance liquid chromatography with diode-array detection. Oregonin content remained comparatively stable during 24 h exposure at 30, 40, 50 and 60 °C, with reductions of 6.00%, 3.00%, 2.78%, and 1.64%, respectively, without clear increase in oregonin loss with increasing temperature. Exposure to 98 °C resulted in the most pronounced decrease in oregonin content, with a reduction of 43.93%. The results indicate comparatively high stability of oregonin during 24 h exposure at 30–60 °C, whereas a pronounced decrease was observed in the separate aqueous treatment at 98 °C. These findings are relevant for understanding chemical changes in alder extractives during wood drying and steaming and demonstrate the importance of minimizing unnecessary heat exposure during sample preparation, extraction, and storage. Full article

The long-term storage of seeds is important for conserving native species, but its effectiveness depends on maintaining seed quality. This study assessed the impact of storage duration on seed quality in Alnus glutinosa (alder) and Betula pubescens (downy birch). Seed quality was evaluated using thousand-seed weight (TSW), moisture content (MC), tetrazolium (TZ) viability, and germination tests. Results from stored seed lots were compared with those from recently collected seeds. Moisture content, TZ viability, and germination were significantly affected by storage duration, although sensitivity analyses indicated that storage conditions, particularly lower temperature and airtight storage, may have contributed to improved seed viability in specific seed lots. A relationship between TZ viability and germination was observed, although this was influenced by zero values. Cold stratification improved germination in downy birch but did not compensate for reduced viability in older seed lots. These findings highlight the importance of storage conditions and species-specific pre-treatments and support the use of TZ testing as a rapid indicator of seed viability when used alongside germination testing. The results provide practical guidance for managing seed resources and maintaining reliable forest reproductive material supply. Full article

Alnus glutinosa (L.) Gaertn. has extensive use in traditional medicine and diverse biological activities due to its rich phytochemical profile. In this study, firstly, the physicochemical characteristics of the plant material were evaluated, revealing a high content of extractive substances (17.684%), followed by ash (6.740%) and moisture (5.000%). Among the bioactive constituents, tannins were the most abundant (7.439%). Analysis of macroelements in the plant ash showed K (11.4330 mg/g) as the predominant element, followed by Mg (97.13 mg/g), Ca (75.30 mg/g), and Na (72.41 mg/g). Trace element analysis indicated Fe (1.2266 mg/g) as the most abundant microelement, with Zn (0.8870 mg/g) and Mn (0.8141 mg/g) present in comparable amounts. Gas chromatography–mass spectrometry (GC-MS) analysis of the ethanolic leaf extract characterized volatile and semi-volatile constituents of 43 phytochemical components, where vitamin E was the predominant compound (20.52%), followed by phytol (12.46%) and squalene (10.29%). Further high-performance liquid chromatography (HPLC) analysis confirmed the presumed presence of naringin (56.421 mg/L), followed by epicatechin (15.123 mg/L), catechin (12.485 mg/L), and phloridzin (11.800 mg/L), while gallic acid was detected at a comparatively lower concentration (0.402 mg/L). The antimicrobial activity of the aqueous leaf extract was evaluated against typical Gram-positive and Gram-negative pathogens, including Staphylococcus aureus, Salmonella abony, Escherichia coli, and Klebsiella pneumoniae. To evaluate the effect of compositional changes on antimicrobial activity, the fermented and non-fermented formulations of A. glutinosa leaf extracts were prepared. These results demonstrate measurable antibacterial effects, thereby confirming the ethnopharmacological significance of A. glutinosa and highlighting its potential as a source of natural antimicrobial agents for further pharmacological development. Full article

The intensity of wildfires is projected to increase with the rising frequency of droughts due to climate change. Management practices following forest fires must include restoring the appropriate species composition. This study was performed within the wider context of the regeneration of soil properties, including the stock and soil organic matter (SOM) content, at the largest forest fire site in Poland (more than 9000 ha) in the Rudziniec Forest District, Upper Silesia. Research plots were established on sandy soils (Podzols and Arenosols) in pure stands of Scots pine (Pinus sylvestris L.), common birch (Betula pendula Roth), and black alder (Alnus glutinosa (L.) Gaertn.). The organic and mineral soil horizons were sampled from each research plot and control plots unaffected by the fire. The trees’ foliage was also sampled to determine the nutrient supply. Basic soil properties were determined, including the texture, pH, bulk density, organic carbon (C), macronutrient contents, soil microbial biomass, and labile C and nitrogen (N) fractions. We found that, 30 years after the fire, the post-fire soils had similar SOC stocks (34.80 Mg ha⁻¹) to the control plots (31.72 Mg ha⁻¹); however, they differed in their stocks of labile C and N fractions. The post-fire soils had a less stable C pool due to a higher stock of the fraction associated with particulate organic matter. In contrast, the N pool was more stable in the post-fire soils than in the control soils due to a lower contribution of the most labile fractions. The soils under Scots pine had the least stable SOM, which may have influenced the intensification of the podzolization process, whereas the highest biomass of soil microorganisms was observed under common birch. The soils under black alder had the highest acidity and lowest phosphorus (P) content. The C:N:P ratios in the post-fire soils and tree foliage indicated that P may have been the limiting factor in alder growth, and N for pine and birch. Our findings indicate that tree species composition is an important factor in the recovery of post-fire soil properties. However, the introduction of pure black alder stands to post-fire soils with low moisture and P availability showed little effectiveness in restoring the SOM content and N pool. Full article

The aim of the present study was to test the central-periphery hypothesis (CPH) of evolutionary genetics in terms of genetic diversity and differentiation in Alnus glutinosa (L.) Gaertn., 1790 and Picea abies (L.) H. Karst. populations. A total of 18 nuclear SSR loci were used to evaluate genetic diversity and differentiation of two rear-edge populations of each tree species from the south-eastern edges of their distribution ranges in Greece, and two populations of each species from the core distribution area in Lithuania. Peripheral populations of A. glutinosa exhibited high genetic diversity (mean Ar = 7.99, mean He = 0.72) and low genetic differentiation (peripheral and core population F_ST were 0.031 and 0.008, respectively). The genetic diversity values were even higher in the peripheral populations of P. abies (mean Ar = 12.27, mean He = 0.78), while genetic differentiation was also low (peripheral and core population F_ST was 0.013 and 0.011, respectively). Genetic differentiation between the peripheral and core regions was also low (F_ST = 0.038 and G″_ST = 0.262 for A. glutinosa and F_ST = 0.023 and G″_ST = 0.172 for P. abies). Observed heterozygosity was found to be higher in peripheral populations (0.80 on average for alder and 0.84 for spruce) than in core ones (0.72 and 0.83 on average for A. glutinosa and P. abies, respectively). On the other hand, expected heterozygosity was higher in A. glutinosa core populations than in its peripheral ones (0.73 vs. 0.72 on average for core and peripheral alder populations), while spruce populations were less heterozygous in the core area (0.78 vs. 0.75 on average for peripheral and core spruce populations, respectively). These results indicate only partial agreement with CPH. Rear-edge populations showed higher genetic differentiation, while their lower genetic diversity was not significantly different from that of core populations. The investigated rear-edge populations of A. glutinosa and P. abies present valuable genetic reserves of European importance. They show local adaptation and present ample genetic variation, and their effective population size will likely be sufficient for adaptive evolution in the future. Their long-term conservation status should be prioritized. 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

Soil erosion and surface runoff on forest road slopes are major environmental concerns, especially in harvested areas, making effective mitigation strategies essential for sustainable forest management. The study compared the effectiveness of three selected woody species on forest road slopes as a possible mitigating action for runoff and soil erosion in harvested sites. Plots measuring 2 m × 3 m were set up with three species—alder (Alnus glutinosa (L.) Gaertn.), medlar (Mespilus germanica L.) and hawthorn (Crataegus monogyna Jacq.)—on the slopes of forest roads. Within each plot, root abundance, root density, canopy percentage, canopy height, herbaceous cover percentage, and selected soil characteristics were measured and analyzed. Root frequency and Root Area Ratio (the ratio between the area occupied by roots in a unit area of soil) measurements were conducted by excavating 50 × 50 cm soil profiles at a 10-cm distance from the base of each plant in the four cardinal directions. The highest root abundance and RAR values were found in hawthorn, followed by alder and medlar in both cases. The same order of magnitude was evidenced in runoff (255.42 mL m⁻² in hawthorn followed by 176.81 mL m⁻² in alder and 67.36 mL m⁻² in medlar) and the reverse order in terms of soil erosion (8.23 g m⁻² in hawthorn compared to 22.5 g m⁻² in alder and 50.24 g m⁻² in medlar). The results of the study confirm that using plant species with dense and deep roots, especially hawthorn, significantly reduces runoff and erosion, offering a nature-based solution for sustainable forest road management. These results highlight the need for further research under diverse ecological and soil conditions to optimize species selection and improve erosion mitigation strategies. Full article

The quantity, quality, and accumulation rate of plant litter play a key role in forest floor flammability and, by extension, fire regimes. The varying foliage properties of different tree species also determine litter’s decomposition and its accumulation on the forest floor. The removal of litter by soil fauna, i.e., bioturbation, depends on both the dominant tree species and the successional stage of the forest stand. This research involved laboratory mesocosm experiments aiming to determine the effects of litter quality and earthworm activity on the flammability of the forest floor material at different successional ages. The mesocosms simulated the planting of four tree species (the broadleaf species Alnus glutinosa (L.) Gaertn. (Black alder) and Quercus robur L. (English oak) and the conifers Picea omorika (Pančić) Purk. (Serbian spruce) and Pinus nigra J.F. Arnold (Austrian pine)) at a reclamation site near Sokolov (NW Czechia). The mesocosms contained litter from these different tree species, placed directly on overburden soil (immature soil) or on well-developed Oe and A layers (mature soil), inoculated or not inoculated with earthworms, and incubated for 4 months. The surface material in the mesocosms was then subjected to simulated burn events, and the fire path and soil temperature changes were recorded. Burn testing showed that litter type (tree species) and soil maturity significantly influenced flammability. Pine had longer burning times and burning paths and higher post-burn temperatures than those of the other tree species. The immature soil with earthworms had significantly shorter burning times, whereas in the mature soil, earthworms had no effect. We conclude that earthworms have a significant, immediate effect on the litter flammability of immature soils. Full article

Invasive plants can significantly alter the composition and functioning of soil ecosystems, which in turn affects soil fauna such as microorganisms; mesofauna including mites, springtails, nematodes, and insects; and other invertebrates. We used clusters of three different tree species to investigate how they affect the composition of belowground soil nematode communities. The clusters included Acer negundo (L.) (an invasive, non-native species), Fraxinus excelsior (L.), and Alnus glutinosa (Gaertn.) (both as native representatives) in floodplain forest habitats of the Morava River. We investigated the families, genera, trophic groups, and functional guilds of soil nematodes in each tree cluster to assess the usefulness of nematodes as indicators of the impact of alien tree species on native communities. The study was complemented by measuring basic soil physico-chemical properties. The data show that nematode communities were not sensitive to A. negundo invasion, as clusters of invasive trees had similar nematode abundance, genus richness, diversity, family and genus composition, and trophic structure compared to species-specific clusters of two native tree species. A cumulative total of 96 nematode genera, belonging to 52 families, were recorded in the investigated floodplain forest sites. The most abundant families across all clusters were Alaimidae, Cephalobidae, Hoplolaimidae, and Rhabditidae for all tree clusters. Among the genera, Helicotylenchus, Pratylenchus, Paratylenchus (as obligate plant parasites), Filenchus, and Malenchus (as facultative plant parasites), as well as Acrobeloides, Eucephalobus, Plectus, and Rhabditis (as bacterivores), were the most dominant taxa. The measured soil properties did not differ significantly among tree species (p < 0.05). Nevertheless, redundancy analysis identified a significant correlation between soil moisture content and abundance of several nematode genera, nematode trophic groups, and functional guilds. The results indicate that the presence of invasive ash-leaved maple trees in the studied floodplain forests had no adverse effect on the diversity and functional structure of soil nematode communities. This study offers initial insights into nematode communities in Acer negundo invaded habitats, but further studies are needed to verify these findings. Full article

Tree species composition, stand structure, and growth dynamics were evaluated within the priority habitat 91E0* (alluvial forests with Alnus glutinosa (L.) Gaertn., and Fraxinus excelsior L.) in the Nestos region of northeastern Greece. This study aimed to understand the ecological dynamics of this unique habitat and to properly plan restoration actions. Measurements were conducted in May and July 2023 across 14 plots distributed randomly along both banks of the Nestos River (east and west). A total of 667 trees with a DBH ≥ 2.5 cm were recorded, representing 13 species and 10 families. Tree densities ranged from 14 to 541 stems ha⁻¹, and the average basal area was 8.77 m² ha⁻¹. Both density and basal area significantly differed between the two riverbanks. Our results indicate that Alnus glutinosa dominates in the alluvial forest, forming more resilient communities with Populus alba L., Populus nigra L., and Salix alba L. However, Fraxinus angustifolia Vahl was not as prevalent as expected. These findings highlight the need for conservation actions and draw attention to the threats facing the alluvial forest. Full article

The priority habitat 91E0*, consisting of alluvial forests with Alnus glutinosa (L.) Gaertn. and Fraxinus excelsior L., represents a vital ecosystem along Europe’s riverbanks and floodplains. In Greece, the alluvial forests of the Nestos Delta are particularly notable for their unique composition and ecological importance. The present study aimed to assess woody species’ regeneration status and diversity in the priority habitat 91E0* in Nestos, Greece. In the studied area, 13 plant species belonging to 12 genera from 10 families were recorded. The most numerous families were Salicaceae (23.07%) and Moraceae (15.38%). The regeneration index (IR) for Amorpha fruticosa L. and Acer negundo L. exhibited a substantial decline, decreasing from 31.75 and 21.12 cm m⁻² to 2.07 and 2.6 cm m⁻², respectively. This intervention created space for expanding native tree species such as Cornus sanguinea L., Morus alba L., and Populus alba L. The results demonstrate that the regeneration of P. alba L. is currently the most extensive (31.1%) in the alluvial forest, with C. sanguinea L., M. alba L., and A. glutinosa (L.) Gaertn. also showing significant regeneration. In contrast, the regeneration of F. angustifolia Vahl remains very limited (0.21 cm m⁻²), indicating the necessity for targeted restoration efforts. Full article

The use of a novel chrono-potentiometry method (abbreviated as “CP”) in the determination of the moisture content in wood (abbreviated as “MC”) above the FSP is a practical application of the electrical charging effect (or ECE). In the specific case of this CP method, the ECE consists of an electrical charging phase for the wood and a discharge phase following the interruption of the charging current. The electrical resistance, R, and the electrical chargeability, Cha(E), of three hardwood species were determined from the final potential, E1, of the charging phase and the initial potential, E2, of the discharge phase, with the three hardwood species being birch (Betula spp.), aspen (Populus spp.), and black alder (Alnus glutinosa (L.) Gaertn). An auxiliary variable in the form of U (E1; E2) was defined as a function of E1 and E2. This was used as an independent electrical variable in the calibration model for a CP moisture meter for the three tree species when it came to the moisture content (MC) region above the FSP (fibre saturation point). It was found that upon a determination of the MC in the wood, the traditional calibration model (the R-model), which uses the electrical resistance of wood, was able to predict a single-measurement precision level of +/−10% for the MC while the U-model predicted a precision level of +/−1.75% for the MC over a single MC measurement in the wood. Full article

Coarse woody debris (CWD) is an essential component in forest ecosystems, playing a significant role in enhancing biodiversity, soil formation, and nutrient cycling through decomposition processes. CWD also contributes to greenhouse gas fluxes, particularly through CO₂ emissions. This study investigated the physical and chemical properties of CWD and the CO₂ effluxes from CWD of different decay classes. For this study, a range of CWD—from recently dead to highly decomposed wood—of native tree species such as silver birch (Betula pendula Roth), black alder (Alnus glutinosa (L.) Gaertn.), and Norway spruce (Picea abies (L.) H. Karst.) in hemiboreal forests were investigated. The findings showed that CWD properties significantly differed among tree species and CWD decay classes. Significant variations in wood density and total nitrogen (N) were observed in the early stages of CWD decay, with the highest values found for the deciduous tree species. The concentration of organic carbon (C) increased throughout the decomposition. The lowest CO₂ efflux from CWD was found for spruce CWD from all decay classes and it was the highest for black alder and silver birch, especially for the 3rd and 4th decay classes. CO₂ efflux was mainly influenced by the degree of decomposition, which was represented by the CWD decay class, followed by wood density and C content. Full article

Over the last 50 years, groundwater levels have been decreasing and air temperatures have been increasing in Poland. Maintaining this trend may make it impossible to maintain hydrogenic habitats in good condition. Reactions to ongoing climate change recorded in tree rings may be a good indicator describing the degree of this threat. The aim of this study was to determine the influence of climatic and hydrological changes on the growth of scotch pine (Pinus sylvestris L.) and black alder (Alnus glutinosa (L.) Gaertn) in the Narew National Park over past 50 years. The research was based on tree increment cores extracted from 42 pine trees and 57 alder trees that were randomly selected and ranged in age from 25 to 88 years, as well as climatic and hydrological data. Standardised data (5-year index) were analysed by species, generation (Y—21–40 years, M—41–60, O—61–90), and decade using correlation analysis. The results of the study show that pine responded more strongly to changes in air temperature and changes in precipitation totals, while alder growth was more strongly related to fluctuations in the water level of the Narew River and changes in precipitation totals. Our research showed that differences in response to environmental factors also occur between tree generations. The decrease in the water level of the Narew River that occurred over the last 50 years did not adversely affect the condition of the trees. Analysis of DBH growth rates showed that the younger generations (Y, M) grow faster than the older generation (O). This is positive news for managers of commercial and protected forests, but accelerated tree growth may be associated with specific consequences, such as increased wind damage as a result of reduced wood density or reduced sensitivity of trees to climate and hydrological changes. Full article