The widespread decline of Norway spruce has led to larger gaps in the canopy of Central European mountain forests, potentially affecting the regeneration of shade tolerant silver fir (Abies alba Mill.). We examined whether greater light availability in canopy gaps influences the morphology of fir needles and fine roots, their carbohydrate concentrations, and their fungal associations, as trees may respond to environmental changes in both their canopy and in their belowground interactions. We compared small patches of fir trees under a closed canopy and low light conditions with regenerating patches growing in gaps with greater light transmission (i.e. canopy gap). We quantified understory photosynthetically active photon flux density (PPFD%), soil water storage, shoot apical dominance, needle specific leaf area (SLA), fine root traits (AD- average diameter, SRL- specific root length, SRA- specific root area), root and leaf tissue nitrogen (N), non-structural carbohydrates (TNC), and characterized root-associated fungi via ITS2 sequencing. Canopy gaps had 1.5 times higher PPFD and reduced soil water storage. Silver fir individuals in canopy gaps also displayed greater apical dominance, thinner roots, and longer SRL and greater SRA compared with individuals under a closed canopy. Contrary to our expectations, the concentrations of soluble sugars and total non-structural carbohydrates were higher under the closed canopy. Meanwhile, gap saplings exhibited higher tissue nitrogen levels in both roots and needles. Light availability also influenced belowground symbiosis as canopy gaps saplings hosted a more diverse ectomycorrhizal fungal community (higher α-diversity), whereas the long-distance morphotype of Boletus occurred under a closed canopy and covaried positively with carbohydrate pools and negatively with SRL. These linked changes illustrate a shift from carbon conservative, symbiont supported growth in shaded patches to more acquisitive root strategies in canopy gaps.

In response to ongoing climate warming, tree species adapted to colder climates are expected to shift their geographic ranges northward. Within the framework of long-term ecological monitoring in Wigry National Park (northeastern Poland), observed changes in forest biocenoses reflect the combined influence of climate change and natural ecological dynamics. This study compares dendroflora composition and diversity between two monitoring periods, 2011 and 2024, as part of an ongoing effort to track climate-related ecological shifts. Tree observations and measurements were carried out using concentric circular plots. In the largest plots, all trees with a diameter at breast height (d.b.h.) >= 12 cm were recorded by species, and their d.b.h. was measured. In the smaller plots, all trees with a d.b.h.>= 2 cm and < 2 cm but taller than 30 cm were similarly identified and measured. Data were recorded with Field-Map software integrated with an electronic calliper. The species-level taxonomic data, individual counts and basal area per species and plot were used to calculate biodiversity indices. Over the 13-year interval, a marked increase in overall dendroflora diversity was observed. Notably, the dominance of canopy-forming conifers - Pinus sylvestris and, to a lesser extent, Picea abies measured as the proportion of individuals or stem density, has declined. This decline of coniferous species has been accompanied by an increase in the abundance and diversity of broadleaved deciduous species, including Tilia cordata, Quercus robur, Betula pendula, and Acer platanoides. Other thermophilous deciduous taxa also exhibited upward trends in both presence and abundance. Furthermore, the exponential of Shannon entropy, reached the highest value when evergreen conifers comprised 35% of the stand composition in 2011 and 18% in 2024. This finding suggests that maximum dendroflora diversity reaches its highest level at an intermediate proportion of conifers presence, rather than under conifers dominance or absence. Collectively, the processes occurring in Wigierski National Park illustrate the gradual shift in ecotonal forest ecosystems from cold-adapted coniferous species to broadleaved deciduous taxa due to ongoing climate change.

This study examines the impact of airborne particulate matter (PM) and associated trace elements (TEs) on deciduous and coniferous trees at the edge of Wigry National Park in northeast Poland, focusing on pollution levels and the potential for phytoremediation. Researchers measured PM concentrations in the air and on the leaves of Picea abies, Quercus robur, and Corylus avellana, along with photosynthetic indicators (Fv/Fm ratio and performance index). The study found significant differences in pollution intensity across areas with varying levels of human activity. P. abies, an evergreen species, accumulated the highest PM levels (>200 μg/cm2), while Q. robur had the highest accumulation among deciduous trees (>50 μg/cm2). Trace elements such as Fe, Cu, Zn, Sr, and Cd were detected, with C. avellana being the most efficient in accumulating Cd (up to 7.5 mg/kg). The accumulation of pollutants correlated with reduced photosynthetic efficiency in trees closest to pollution sources. The findings suggest that strategically planting specific tree species can help mitigate air pollution in national parks and protect sensitive vegetation. Future research should explore the long-term effects of PM on forest health and the role of different species in phytoremediation.

The anatomical characteristics of ectomycorrhizal exploration types in response to soil variability remain insufficiently understood. We examined the root anatomy of contact and long-distance exploration types in Pinus sylvestris and Quercus petraea, species with distinct ecological needs, across different soil horizons. The diameter of ectomycorrhizal roots, the root absorptive traits i.e. proportion of cortex and mantle area, the percentage stele in the diameter, and the weighted average diameter of vessels (Ra) in the ectomycorrhizas were measured within ectomycorrhizas collected from organic and mineral soils across the soil profile. The absorptive traits varied along soil horizons, in which water and nutrient availability changed inversely. The proportion of cortex was associated with exploration type, but was not specific to tree species. However, the ectomycorrhizal diameter and the percentage of mantle within the root forming contact exploration type of P. sylvestris showed no variation among soil horizons. In contrast, the soil horizon significantly influenced all root anatomical traits in the contact exploration type of Q. petraea by enhancing the contribution of the absorption area of the root area, mainly in the illuvial horizon, but reaching the smallest value in the organic horizon. The Ra and the cell wall thickness of the vessels were strongly dependent on tree species. With increasing soil depth, Ra in Q. petraea increased, and stele proportion in root diameter decreased. The results suggest that water acquisition traits differ among tree species, but traits associated with nutrient absorption (proportion of cortex and mantle area) within specific soil horizons are closely related to the ectomycorrhizal exploration type.

Rhizosphere microbial communities can influence plant growth and development. Natural regeneration processes take place in the tree stands of protected areas, which makes it possible to observe the natural changes taking place in the rhizosphere along with the development of the plants. This study aimed to determine the diversity (taxonomic and functional) of the rhizosphere fungal communities of Norway spruce growing in one of four developmental stages. Our research was based on the ITS region using Illumina system sequencing. Saprotrophs dominated in the studied rhizospheres, but their percentage share decreased with the age of the development group (for 51.91 from 43.13%). However, in the case of mycorrhizal fungi, an opposite trend was observed (16.96–26.75%). The most numerous genera were: saprotrophic Aspergillus (2.54–3.83%), Penicillium (6.47–12.86%), Pyrenochaeta (1.39–11.78%), pathogenic Curvularia (0.53–4.39%), and mycorrhizal Cortinarius (1.80–5.46%), Pseudotomentella (2.94–5.64%) and Tomentella (4.54–15.94%). The species composition of rhizosphere fungal communities was favorable for the regeneration of natural spruce and the development of multi-generational Norway spruce stands. The ratio of the abundance of saprotrophic and mycorrhizal fungi to the abundance of pathogens was high and promising for the durability of the large proportion of spruce in the Wigry National Park and for forest ecosystems in general.

Long-term minirhizotron observations of absorptive fine roots provide insights into seasonal patterns of belowground root production and carbon dynamics. Our objective was to compare root dynamics over time across mature individuals of 11 temperate trees species: five evergreen and six deciduous. We analyzed the timing and growth on 1st-and 2nd-order roots in minirhizotron images down to a vertical depth of 35 cm, as well as monthly and total annual length production. Production patterns were related to total annual precipitation of the actual and previous year of root production over 6 years. The main or largest peak of annual fine-root production occurred between June and September for almost all species and years. In most years, when peaks occurred, the timing of peak root production was synchronized across all species. A linear mixed model revealed significant differences in monthly fine-root length production across species in certain years (species x year, P < 0.0001), which was strongly influenced by three tree species. Total annual root production was much higher in 2000–2002, when there was above-average rainfall in the previous year, compared with production in 2005–2007, which followed years of lower-than-average rainfall (2003–2006). Compared to the wetter period all species experienced a decline of at least 75% in annual production in the drier years. Total annual root length production was more strongly associated with previous year’s (P < 0.001) compared with the actual year’s precipitation (P = 0.003). Remarkably similar timing of monthly absorptive fine-root growth can occur across multiple species of diverse phylogeny and leaf habit in a given year, suggesting a strong influence of extrinsic factors on absorptive fine-root growth. The influence of previous year precipitation on annual absorptive fine-root growth underscores the importance of legacy effects in biological responses and suggests that a growth response of temperate trees to extreme precipitation or drought events can be exacerbated across years.

Long-distance-exploration type (LDET) ectomycorrhizae have been reported to be best adapted to infertile soils, but variation within LDET ectomycorrhizae have not been thoroughly examined. Concentrations of nitrogen (N) and carbon (C) in LDET ectomycorrhizae were examined in Xerocomus-Pinus sylvestris and Scleroderma-Quercus petraea ectomycorrhizae. The study determined how concentrations of these elements vary in ectomycorrhizae in fertile (organic, uppermost mineral) and infertile (brunic) soil layers. The organic horizon in both Scots pine and sessile oak forest soils had the highest mineral status and exchange cations. In contrast, low mineral concentrations, high base saturation, and pH were characteristic of the brunic horizon in both forest stands. Xerocomus ectomycorrhizae had a higher concentration of N in the fertile (organic and uppermost mineral) soil horizons (3.4%) than in the infertile (brunic) soil horizon (2.2%). N concentration in Scleroderma ectomycorrhizae varied from 2.8%-3.0 % and did not differ between the studied soil horizons. The mean concentration of carbon in Xerocomus ectomycorrhizae varied from 29%-46% in Scots pine stands and from 41%-44% in Scleroderma ectomycorrhizae in sessile oak stands. The concentration of carbon in both Xerocomus and Scleroderma ectomycorrhizae was significantly higher in the fertile horizons (organic and uppermost mineral) compared to the brunic (infertile) horizon. In summary, the analysis conducted in the present study indicates that the LDET ectomycorrhizae, Xerocomus and Scleroderma, possess inherent variations in C and N content to manage soil resources.

Key message Quercus robur seedling mass was affected more by planting density than by taproot pruning. Root pruning enhanced stem biomass at the expense of roots in later growth stages. Alteration of biomass allocation due to nursery practices may result in greater susceptibility to injury and death of the seedlings under unfavorable environmental conditions . Context Plants adjust their growth and modulate the resource allocation in response to applied treatments and environmental conditions. Aims The aim was to examine how taproot pruning in seedlings grown at different densities affected long-term growth of Quercus robur . Methods Seedlings, sown as acorns at two planting densities, with or without pruned roots were harvested in the second, fourth, and fifth years of growth. The effect of root pruning on biomass allocation was determined by measuring leaf, stem, and root mass fractions; carbohydrate concentrations in the roots; and C/N ratios. Specific leaf area and root length were also determined to assess morphological adaptations to growth conditions. Results Total seedling mass was affected more by planting density than by taproot pruning. After 4 years of growth, root mass fractions were lower and stem mass fractions were greater in seedlings planted at a higher density. Five-year old root-pruned seedlings also had a lower root mass fraction and higher stem mass fractions than unpruned seedlings. Specific root length was not affected by root pruning or planting density. Conclusion Decrease of relative root biomass with simultaneous increase of stem biomass may be a long-term consequence of taproot pruning of Q . robur , and the effects may manifest years after the seedling stage.

Mesostigmatid mites are one of the natural elements of soil fauna, but they are also found in decomposing wood. Many studies have focused on mites in decayed logs; however, information about the mite communities in decayed stumps and additionally in the adjacent litter is scarce. The primary objective of this study was to analyze how the mite fauna differs between Scots pine (Pinus sylvestris L.) and sessile oak [ Quercus petraea (Matt.) Liebl.] stumps, as well as to discover how much the stumps affect the soil mite community in temperate forests. This study was conducted in two managed forests (pine versus oak) in five microhabitats [ clear-cut stumps, ecotone, and litter at three distances (0.5, 1.0, and 1.5 m)]. The forests were 98 years old, growing in brownish, rusty soil and were located in the Murowana Goslina Forest Experimental Station (Poznan, Central Poland). Our study revealed that the mean number of species, mean abundance, and evenness differed between the pine and oak forests. Additionally, the study indicated that Scots pine and sessile oak clear-cut stumps as well as the adjacent litter (up to 1.5 m away) were inhabited by the same abundant mite species. Moreover, unique species such as Oplitis minutissima and Pergamasus mediocris were restricted in distribution to ecotone in the Scots pine forest.

American black cherry (Prunus serotina Ehrh.) is an alien invasive tree species, which currently can be found in large numbers in many ecosystems in Poland. It grows relatively fast, reproduces very easily and occupies ecological niches of some native tree species. The main objective of this study was to estimate the number and basic biometric traits, such as height and diameter, of young black cherries growing on abandoned farmland in different light conditions. Ten square (10 × 10 m) sample plots were marked under the canopy of Scots pine small pole stand originating from afforestation. Another ten sample plots were marked in the open area of abandoned armland covered mostly by herbaceous plants, located in the close vicinity to the stand. The two sites are the part of Zielonka Forest (52°33' N, 17°06' E), situated in west-central Poland. All black cherries growing in each of the twenty sample plots were counted and their height and diameter was measured. In case of the sample plots located inside the pine stand also light measurements were performed, to estimate light availability under the canopy of the stand. Simultaneously light was measured in the open area as the reference and expressed as photosynthetic photon flux (PPF). Our results indicate that number of black cherries growing under the canopy of the pine stand was significantly higher than those growing in the open space. Number of black cherries in the stand was negatively correlated with number of pines forming the stand’s main canopy, but at the same time we found no correlation between the amount of sunlight inside the stand and number of black cherries. Black cherries growing in the open area were higher and thicker than the ones growing under the canopy of the pine stand, but differences in height and diameter between these two groups were relatively small. This is an Open Access article distributed under the terms of Creative Commons Attribution 4.0 International License , which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

In general, respiration (RS) is highly correlated with nitrogen concentration (N) in plant organs, including roots, which exhibit a positive N-RS relationship. Less is known, however, about the relationship between N and RS in roots of different branch orders within an individual tree along a vertical soil profile; this is especially true in trees with contrasting life strategies, such as pioneer Scots pine (Pinus sylvestris L.) vs mid-successional sessile oak (Quercus petraea Liebl.). In the present research, the impact of root branch order, as represented by those with absorptive vs transporting ability, and soil genetic horizon on root N, RS and the N-RS relationship was examined. Mean RS and total N concentration differed significantly among root branch orders and was significantly higher in absorptive roots than in transporting roots. The soil genetic horizon differentially affected root RS in Scots pine vs sessile oak. The genetic horizon mostly affected RS in absorptive roots of Scots pine and transporting roots in sessile oak. Root N was the highest in absorptive roots and most affected by soil genetic horizon in both tree species. Root N was not correlated with soil N, although N levels were higher in roots growing in fertile soil genetic horizons. Overall, RS in different root branch orders was positively correlated with N in both species. The N-RS relationship in roots, pooled by soil genetic horizon, was significant in both species, but was only significant in sessile oak when roots were pooled by root branch order. In both tree species, a significant interaction was found between the soil genetic horizon and root branch order with root function; however, species-specific responses were found. Both root N, which was unaffected by soil N, and the positive N-RS relationship consistently observed in different genetic horizons suggest that root function prevails over environmental factors, such as soil genetic horizon.

The allocation of resources to chemical defense can decrease plant growth and photosynthesis. Prunasin is a cyanogenic glycoside known for its role in defense against herbivores and other plants. In the present study, fluctuations of prunasin concentrations in roots of Prunus serotina seedlings were hypothesized to be: (1) dependent on light, air temperature, and humidity; (2) affected by competition between Prunus serotina and Quercus petraea seedlings, with mulching with Prunus serotina leaves; (3) connected with optimal allocation of resources. For the first time, we determined prunasin concentration in roots on several occasions during the vegetative season. The results indicate that seasonal changes have more pronounced effects on prunasin concentration than light regime and interspecific competition. Prunus serotina invested more nitrogen in the synthesis of prunasin under highly restricted light conditions than in higher light environments. In full sun, prunasin in roots of Prunus serotina growing in a monoculture was correlated with growth and photosynthesis, whereas these relationships were not found when interspecific competition with mulching was a factor. The study demonstrates that prunasin concentration in Prunus serotina roots is the result of species-specific adaptation, light and temperature conditions, ontogenetic shift, and, to a lesser extent, interspecific plant-plant interactions.

The objective of the study was to estimate biomass and selected morphological traits of fine roots (diameter ≤ 2 mm) in 26-year-old Scots pine stand originating from afforestation and growing as the first forest generation on formerly arable land. The stand is located about 30 km north-east from Poznań (western Poland) in the Murowana Goślina Experimental Forest Division, which belongs to Poznań University of Life Sciences. 20 sample trees were selected. Within a distance of 30 cm from each tree intact soil cores were sampled from 3 depths in the soil: 0–20, 21–40 and 41–60 cm. The total number of samples was 120. All roots were separated from the soil, scanned, dried to constant mass and weighed. Fine root biomass and morphological traits (such as: length, surface area, volume and number of root tips) decreased with soil depth. The only exception was diameter, which increased with soil depth.

The influence of different shade conditions biomass of sessile oak seedlings growing in interaction with invasive black cherry. In May of 2011 a randomized pot study was established. The current year sessile oak and invasive black cherry seedlings were grown in controlled light (100, 25 and 5% of full light), competition and allelopathy (3 oaks + 6 cherries; 3 oaks + 6 cherries + cherry leaves) and allelopathy (3 oaks + cherry leaves) conditions. Pots with three oak and three cherry seedlings accounted for the control treatment. The competition had a negative effect on biomass of both species. Black cherry leaves added to substrate stimulated biomass production of oak’s seedlings. In the treatment of competition the cherry leaves decreased negative influence of the species on each other. In the end of the vegetative season in 100 and 25% of full light cherry seedlings had larger total biomass of about a half than oak seedlings. In 5% of full light, inversely, oak had larger biomass than cherry. This result suggests that in strong shade, sessile oak seedlings are able to compete for light with black cherry more effectively compared with the moderate and high light environments.

Root turnover is fastest in the finest roots of the root system (first root order). Additionally, tissue chemistry varies among even the finest root orders and between white roots and older, pigmented roots. Yet the effects of pigmentation and order on root decomposition have rarely been examined. We separated the first four root orders (all,1 mm) of four temperate tree species into three classes: white first- and second-order roots; pigmented first- and second-order roots; and pigmented third-and fourth-order roots. Roots were enclosed in litterbags and buried under their own and under a common species canopy in a 34-year-old common garden in Poland. When comparing decomposition of different root orders over 36 months, pigmented third-and fourth-order roots with a higher C:N ratio decomposed more rapidly, losing 20-40% of their mass, than pigmented first- and second-order roots, which lost no more than 20%. When comparing decomposition of roots of different levels of pigmentation within the same root order over 14 months, pigmented (older) first- and second-order roots lost; 10% of their mass, while white (younger) first- and second-order roots lost; 30%. In contrast to root mass loss, root N content declined more rapidly in the first- and second-order roots than in third-and fourth-order roots. In higher-order roots, N increased in the first 10 months from; 110% to nearly 150% of initial N content, depending on species; by the end of the study N content had returned to initial levels. These findings suggest that, in plant communities where root mortality is primarily of pigmented first- and second-order roots, microbial decomposition may be slower than estimates derived from bulk fine-root litterbag experiments, which typically contain at least four root orders. Thus, a more mechanistic understanding of root decomposition and its contribution to ecosystem carbon and nutrient dynamics requires a fundamental shift in experimental methods that stratifies root samples for decomposition along more functionally based criteria such as root order and pigmentation, which parallel the markedly different longevities of these different root classes.