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Summary: We investigate the impact of a 20‐yr irrigation on root water uptake (RWU) and drought stress release in a naturally dry Scots pine forest.We use a combination of electrical resistivity tomography to image RWU, drone flights to image the crown stress and sensors to monitor soil water content.Our findings suggest that increased water availability enhances root growth and resource use efficiency, potentially increasing trees' resistance to future drought conditions by enabling water uptake from deeper soil layers.This research highlights the significant role of ecological memory and legacy effects in determining tree responses to environmental changes. [ABSTRACT FROM AUTHOR]

ABSTRACT Large and highly repetitive genomes are common. However, research interests usually lie within the non‐repetitive parts of the genome, as they are more likely functional, and can be used to answer questions related to adaptation, selection and evolutionary history. Exome capture is a cost‐effective method for providing sequencing data from protein‐coding parts of the genes. C0t‐1 DNA blockers consist of repetitive DNA and are used in exome captures to prevent the hybridisation of repetitive DNA sequences to capture baits or bait‐bound genomic DNA. Universal blockers target repetitive regions shared by many species, while species‐specific c0t‐1 DNA is prepared from the DNA of the studied species, thus perfectly matching the repetitive DNA contents of the species. So far, the use of species‐specific c0t‐1 DNA has been limited to a few model species. Here, we evaluated the performance of blocker treatments in exome captures of Pinus sylvestris, a widely distributed conifer species with a large (> 20 Gbp) and highly repetitive genome. We compared treatment with a commercial universal blocker to treatments with species‐specific c0t‐1 (30,000 and 60,000 ng). Species‐specific c0t‐1 captured more unique exons than the initial set of targets leading to increased SNP discovery and reduced sequencing of tandem repeats compared to the universal blocker. Based on our results, we recommend optimising exome captures using at least 60,000 ng of species‐specific c0t‐1 DNA. It is relatively easy and fast to prepare and can also be used with existing bait set designs. [ABSTRACT FROM AUTHOR]

The severity of droughts is expected to increase with climate change, leading to more frequent tree mortality and a decline in forest ecosystem services. Consequently, there is an urgent need for monitoring networks to provide early warnings of drought impacts on forests. Dendrometers capturing stem diameter variations may offer a simple and relatively low-cost opportunity. However, the links between stem shrinkage, a direct expression of tree water deficit (TWD), and hydraulic stress are not well understood thus far. In this study, we exposed two widespread conifers Pinus sylvestris L. and Larix decidua Mill. to lethal dehydration by withholding water and closely monitored TWD, midday water potential (⁠|$\psi $|⁠) and midday stomatal conductance (⁠|${\textit g}_{\textit s}$|⁠) under controlled greenhouse conditions. We found strong relationships between the three variables throughout the dehydration process, particularly suggesting the potential for continuous |$\psi $| predictions and stomatal closure assessments. However, the relationships decoupled during recovery from severe drought. We also identified TWD thresholds that signal the onset of drought stress and tissue damage, providing insights into stress impacts and recovery potential. While these findings are promising, challenges remain in practically transferring them to field set-ups by suitable TWD normalization. Importantly, we observed that midday |${\textit g}_{\textit s}$| was drastically reduced when TWD persisted overnight, providing a directly applicable drought stress signal that does not require normalization. In conclusion, while challenges remain, our results highlight the potential of dendrometers for monitoring tree water dynamics. Implementing dendrometer networks could support the development of early warning metrics for drought impacts, enabling large-scale monitoring in diverse settings, such as urban areas and forest ecosystems. [ABSTRACT FROM AUTHOR]

The effect of 1/2 LV, MSG, DCR-based nutrient media with different content of 2.4-D, BA and carbohydrate sources (maltose, sucrose) on the response of Pinus sylvestris L. megagametophytes containing immature embryos was studied. Plant material was collected from 10–40-year-old trees growing in Petrozavodsk seed orchard, progeny trial, and city park. A total number of 3260 and 1860 megagametophytes were cultivated in vitro in 2022 and 2023, respectively. Most frequently embryonal-suspensor mass formation occurred from explants collected from plus trees' clones at Petrozavodsk seed orchard and did not exceed 0.3%. The study identified a donor-tree genotype (864-2) whose explants, collected in different years, formed embryogenic cell masses proliferating for 9–10 months. It has been recommended to use the MSG nutrient medium for the successful embryonal-suspensor mass initiation. Prolonged embryonal-suspensor mass cultivation on the medium with high phytohormone content led to its degradation and required subculturing on the substrate with lower auxin and cytokinin content. In this study, we have induced the process of Pinus sylvestris somatic embryos maturation up to the clearly visible globular stage. [ABSTRACT FROM AUTHOR]

Aims: Facilitation is common among plants, but our understanding of indirect belowground facilitative mechanisms is limited. We followed up on previous research showing that Pinus sylvestris had strong facilitative effects on co-occurring Amorpha fruticosa shrubs by testing the effects of root exudates of the Pinus on various components of the N cycle in the soil around Amorpha roots. Methods: We applied different concentrations of Pinus root exudates (0, 1x, and 4x) to soils, and measured the responses of the soil metabolome, microbial functional groups and the biomass of Amorpha. Results: A 1x concentration of Pinus root exudates promoted microbial metabolism and plant secondary metabolite biosynthesis. The same concentration increased the abundance of specific microbial genera in the rhizosphere involved in nitrification and nitrogen (N) fixation. These root exudates also increased the abundance of microbial taxa and genes involved in ammonification and nitrification, but inhibited microbial denitrification. In addition, pathway analysis indicated that Pinus root exudates indirectly facilitate Amorpha biomass by regulating its rhizosphere N-cycle. Together, these results indicate that 1x concentrations of Pinus root exudates promote the efficient conversion of ammonium to nitrate and the absorption and utilisation of organic N, while reducing gaseous N losses, thereby promoting the overall N uptake, and potentially growth, of Amorpha. Conclusions: Our results point to the importance of root exudates as an indirect facilitative mechanism, operating through effects on microbes involved in the N cycle, but their ecological relevance should be further validated in the field. [ABSTRACT FROM AUTHOR]

Forests are essential to climate change mitigation through carbon sequestration, transpiration, and turnover. However, the quantification of climate change impacts on forest growth is uncertain and even contradictory in some regions, which is the result of spatially constrained studies. Here, we use an unprecedented network of 1.5 million tree growth records from 493 Picea abies and Pinus sylvestris stands across Europe to predict species‐specific tree growth variability from 1950 to 2016 (R2 > 0.82) and develop 21st‐century gridded projections considering different climate change scenarios. The approach demonstrates overall positive effects of warming temperatures leading to 25% projected conifer growth increases under the SPP370 scenario, but these additional carbon gains are spatially inhomogeneous and associated with geographic climate gradients. Maximum gains are projected for pines in Scandinavia, where growth trajectories indicate 50% increases by 2071–2100. Smaller but significant growth reductions are projected in Mediterranean Europe, where conifer growth shrinks by 25% in response to warmer temperatures. Our results reveal potential mitigating effects via forest carbon sequestration increases in response to global warming and stress the importance of effective forest management. [ABSTRACT FROM AUTHOR]

Managing forests for timber yields reduces the amounts of old trees and deadwood, which has profound effects on species that are dependent on them. Retention forestry, where some trees are permanently left unharvested on clear‐cut sites, may enable the formation of deadwood and old trees in managed forests, but it is unresolved how well these practices facilitate the occurrence of species in managed forests, especially in the long term.We studied the capacity of tree retention practices to support the diversity of epiphytic lichens, a key group among threatened forest species. We compared lichen assemblages on retained trees in harvested sites to those on trees in unharvested control sites. The data were collected 21‐year post‐harvest and included living trees, snags (standing dead trees) and logs (fallen trees) of Pinus sylvestris (Scots pine).Living trees, snags and logs each hosted distinct lichen communities. The highest lichen diversity was found on snags.On living trees, species richness was similar in harvested and unharvested sites, but there was slight species turnover. In contrast, deadwood in unharvested sites hosted higher species richness and distinct species assemblages compared to deadwood in harvested sites. These differences were most pronounced on snags. Specifically, unharvested sites contained high‐longevity snags (kelo trees), which hosted unique lichen communities with higher lichen richness than any other studied substrate, including the highest numbers of red‐listed and deadwood‐dependent species.Synthesis and applications. Retention forestry can support lichen assemblages associated with living Pinus sylvestris. However, maintaining deadwood‐associated lichen diversity through retention practices entails significant challenges. Deadwood‐associated lichen diversity relies on high‐longevity snags and is not sustained by the habitats provided in retention forestry. Biodiversity maintenance in forest management requires comprehensive provision of the habitat features of unmanaged forests, such as a qualitatively representative deadwood profile, which can prove difficult. [ABSTRACT FROM AUTHOR]

Climate change means that in many areas in boreal region, the duration and thickness of the winter snow cover is decreasing. Young seedlings are exposed to fluctuating winter temperatures in the absence of protecting snow cover. Responses to winter warm and cold spells were studied with Scots pine (Pinus sylvestris L.), silver birch (Betula pendula Roth.), and Norway spruce (Picea abies (L.) Karts.) container seedlings in Finland. The frost hardiness of whole seedlings and buds was determined for seedlings sampled directly from outdoor overwintering conditions, after 7-day deacclimation (+5 °C; +7 °C in late March) and deacclimation combined with 7-day reacclimation (− 7 °C) treatments between January and late March. The frost hardiness of buds and whole seedlings in Scots pine was between − 40 and − 30 °C from January to early March. Norway spruces tolerated at least − 50 °C in midwinter, but their frost hardiness in outdoor conditions decreased more rapidly in March than that of Scots pines. Silver birch tolerated − 30 °C in February. During simulated warm spells, the Scots pine and silver birch deacclimated without an ability to reacclimate during simulated cold spells. The buds and whole seedlings of Norway spruces also deacclimated, but they had some ability to reacclimate in February and early March, but not in late March. In Nordic boreal conditions, one-year-old Scots pines and silver birches respond strongly to fluctuating winter temperatures during snowless winters, whereas Norway spruces can tolerate typical winter temperatures in midwinter, but their frost hardiness may reduce during warm spells in March. [ABSTRACT FROM AUTHOR]

In 2020, five eurytomid species were found for first time on bark beetles in Pinus sylvestris plantations in Ihtimanska Sredna Gora Mountains in Bulgaria: Eurytoma afra Boheman, 1836, Eurytoma arctica Thomson, 1875, Eurytoma morio Boheman, 1836, Eurytoma sp.1 and Eurytoma sp.2. One of them, E. arctica is a new species for the Bulgarian fauna. The parasitoids were reared from stem and branch samples infested by Ips acuminatus, Pityogenes bistridentatus, Pityophthorus pityographus, Tomicus piniperda and T. minor. All host-parasitoid associations are new for Bulgaria. In parasitoid complex, the most abundant species was E. morio (75.9%), followed by E. arctica (13.8%), Eurytoma sp. (6.9%) and E. afra (3.4%). The parasitism of the hosts varied between 2.6% (E. afra on I. acuminatus, P. bistridentatus and P. pityographus) and 33.3% (E. morio on I. acuminatus).

Diplodia sapinea causes Diplodia tip blight (DTB) and is recognised as an opportunistic necrotrophic pathogen affecting conifers. While DTB is associated with abiotic stress, the impact of biotic stress in the host on D. sapinea's lifestyle shift is unknown. Observed co‐occurrences of D. sapinea and Melampsora pinitorqua, causing pine twisting rust on Scots pine (Pinus sylvestris), instigated an investigation into their interaction with and influence on the defence mechanisms of the host. We hypothesised that M. pinitorqua infections predispose the trees to D. sapinea by stressing the host and altering the shoot metabolites. Pines in a plantation were sampled over time to study pathogen biomass and host metabolites. Symptoms of both pathogens were consistent over years, and the preceding season's symptoms affected the metabolic profiles pre‐infection and M. pinitorqua's proliferation. Symptoms of M. pinitorqua altered shoot metabolites more than fungal biomass, with co‐symptomatic trees exhibiting elevated M. pinitorqua biomass. Specific phenolic compounds had a strong positive association with the shoot symptom × D. sapinea interaction. D. sapinea's biomass presymptoms was independent of previous disease symptoms and infection by M. pinitorqua. Some trees showed disease tolerance, with delayed rust infections and minimal DTB symptoms. Further investigations on this trait are needed. Summary statement: This study examines the dynamics of disease outbreaks caused by the emerging pathogen D. sapinea in Scots pines in northern Europe, concurrently infected by the native pathogen M. pinitorqua. Disease symptoms vary across the studied trees, from severely affected trees to those that show tolerance by delayed rust infections and low Diplodia tip blight disease levels. Disease symptoms persist over the years and predict the pathogen dynamics, phenolic profiles and tree vitality. M. pinitorqua infection does not directly impact D. sapinea colonisation. [ABSTRACT FROM AUTHOR]

Entomopathogenic fungi (EPFs) are important factors in the biological control of many insect pests, and these microorganisms often cause widespread epizootics in pest populations. In addition to the use of EPFs as microbial control agents, recent studies show that these fungi can live endophytically with plants. These endophytes are also known to play a role in plants to protect them against insects, pathogens, and nematodes. In this study, it was aimed to isolate and molecularly characterize endophytic entomopathogenic fungi from yellow pine forests in Kırşehir province, Türkiye, and test them against Diprion pini L. (Hymenoptera: Diprionidae). Endophytic entomopathogenic fungus isolation was carried out using a selective medium from a total of 234 healthy needle samples (three from each branch) from 117 branches (two from each tree) from 39 yellow pine trees. After the isolation studies, a total of 24 fungi (10.25% based on the needle number) were isolated and purified. The isolated fungi were then characterized by gene sequencing (Bloc gene for Beauveria spp. and β-tubulin for Metarhizium spp.) and phylogenetic analysis. Twenty isolates were identified as B. bassiana, and four isolates were identified Metarhizium majus. All isolates were also tested against D. pini larvae, and different mortalities were recorded. The highest mortality values were obtained from Beauveria bassiana AD-9, AD-12, and AD-16 with 96.66, 76.66, and 96.66%, respectively. The highest mycoses were obtained from B. bassiana AD-9 and AD-16 with 96.66 and 90%, respectively. These results should be beneficial and provide new opportunities in the control of pine pests using endophytic entomopathogenic fungi. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.), a keystone species in Eurasian forests, supports diverse fungal communities and thus contributes to forest health and ecosystem functions. The southern marginal populations of P. sylvestris in Türkiye, situated in more arid and warm conditions, offer a unique environment to explore fungal biodiversity. In this study, the authors investigated the fungal assemblages in living (green) and dead (senescent, fallen, and litter) Scots pine needles in Türkiye. Using a culture-based approach coupled with DNA sequencing, distinct fungal communities were identified across different needle types. Frequent isolates included well-known P. sylvestris associates, including Lophodermium pinastri, Sydowia polyspora, and Cyclaneusma minus. Novel findings, such as unidentified Eurotiomycete and Basidiomycete taxa, suggest potentially new species and hidden fungal diversity in this biogeographically important region. Additionally, this study reports the first records of Desmazierella acicola and Phacidium lacerum in Türkiye, further underscoring the region’s underexplored fungal biodiversity. Moreover, the biodiversity and community structure analysis revealed the intricate and complex nature of fungal colonization and succession, with significant variations between green, senescent, freshly fallen, and litter needles sampled concurrently. These findings provide new insights into the fungal communities of marginal, understudied Scots pine populations.

The seed production and quality of Pinus sylvestris seeds in forest plantations on the Crimean yaylas has been studied. The dynamics of biometric indicators of cones and seeds by year and in connection with the peculiarities of growing conditions has been characterized. Significant differences in the quality of seeds of P. sylvestris trees have been revealed in terms of the level of germination energy. It has been shown that, along with the temperature regime, a significant impact on the effectiveness of P. sylvestris reproduction processes is exerted by air humidity and the nature of precipitation, as well as the dynamics of air mass movement, since the success of pollination is determined by the quantity and quality of pollen that has reached the female reproductive structures. Based on the analysis of weather phenomena and the dynamics of seed quality, it has been found that the level of seed germination is best reflected by an integrated index that takes into account the combined effect of several factors – the dryness index. In addition, the results of the analysis allowed us to conclude that the efficiency of the pollination process of female cones of P. sylvestris under yayla conditions is most likely influenced by the number of hours of sunshine. The germination energy and seed germination differ not only within the studied plantations, but also depending on the year of study. During the observation period, the forest plantations of the Ai-Petrinskaya Yayla have produced the highest quality seeds. In 2014, in the plantations with a density of 0.5, the seed germination rate was 74.5±2.2 %. The lowest level of germination energy and seed germination has been noted in artificial plantations of P. sylvestris on the Tirke Yayla; in 2012, these indicators here amounted to 15.2±0.7 and 46.2±2.1 %, respectively. In general, the development of the generative sphere of P. sylvestris in artificial plantations on the Crimean yaylas is quite effective. Based on this, a conclusion has been made that the growing conditions on the yaylas are favourable for the implementation of the initial stages of the ontogenesis of the species.

The impact of chronic radiation exposure on phytohormone content and expression of phytohormone- and stress-related genes of Scots pine in the zone affected by the Chernobyl accident was studied. Needle samples were collected from three plots with contrasting levels of radioactive contamination in the Polesye State Radiation-Ecological Reserve, Republic of Belarus, and two reference plots in the Kozeluzhsky forest in June 2022. The experimental plots were located within the artificial plantations of Scots pine established in 1982, before the accident in 1986. The activity of radionuclides 137Cs, 90Sr, 241Am, 238Pu, and 239+240Pu in soil and needles ensured dose rates ranging from 3.3 to 87 mGy × year−1, while at the reference plots, the range was 0.7‒0.8 mGy × year−1. Concentrations of plant hormones, including indole-3-acetic acid (IAA), indole-3-butyric acid (IBA), zeatin, and abscisic acid (ABA) in needles were evaluated using high-performance liquid chromatography (HPLC). We demonstrate that chronic radiation exposure is a significant stress factor that affects both phytohormonal balance and the expression of some important phytohormone- and stress-related genes. We found a tendency toward decreased ABA and auxin concentrations in trees from plots contaminated with radionuclides. The ratio (IAA + IBA + zeatin)/ABA was drastically raised at the most contaminated plots Masany and Kulazhin, reflecting the functional rearrangements of cellular metabolism that ensure plant adaptation under chronic radiation exposure. Changes in gene expression indicated modulation of ABA and Ca2+ signalling pathways, decreased potential of zeatin biosynthesis, and activation of heat shock proteins biosynthesis. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.), a keystone species in Eurasian forests, supports diverse fungal communities and thus contributes to forest health and ecosystem functions. The southern marginal populations of P. sylvestris in Türkiye, situated in more arid and warm conditions, offer a unique environment to explore fungal biodiversity. In this study, the authors investigated the fungal assemblages in living (green) and dead (senescent, fallen, and litter) Scots pine needles in Türkiye. Using a culture-based approach coupled with DNA sequencing, distinct fungal communities were identified across different needle types. Frequent isolates included well-known P. sylvestris associates, including Lophodermium pinastri, Sydowia polyspora, and Cyclaneusma minus. Novel findings, such as unidentified Eurotiomycete and Basidiomycete taxa, suggest potentially new species and hidden fungal diversity in this biogeographically important region. Additionally, this study reports the first records of Desmazierella acicola and Phacidium lacerum in Türkiye, further underscoring the region's underexplored fungal biodiversity. Moreover, the biodiversity and community structure analysis revealed the intricate and complex nature of fungal colonization and succession, with significant variations between green, senescent, freshly fallen, and litter needles sampled concurrently. These findings provide new insights into the fungal communities of marginal, understudied Scots pine populations. [ABSTRACT FROM AUTHOR]

Scots pine is of greatest importance in northern Germany regarding its cultivation area and expected capability to perform in climate change. However, pine predominantly occurs in monocultures. Therefore, future pine forestry depends on an adaptation to climate change while improving ecological and economic forest functions. Yet future development of pine remains uncertain due to leeway in silvicultural guidelines and future climate. This study questions: (i) what is the range of future pine shares under climate change and different silvicultural management in northern Germany, (ii) how will the current stands develop and (iii) what is the range of uncertainty arising from climate models and silvicultural options? To answer these issues we (i) selected forest development types site- and climate-sensitively to either minimize or to maximize pine shares, (ii) simulated four, now practiced forest management scenarios for 50 years based on the German National Forest Inventory and (iii) analyzed the differences, to be interpreted as uncertainty. Novel to our approach is the site- and climate-sensitive selection of forest development types on large scales which emphasizes the contrasts of the different management guidelines. The results show that growing stock and cultivation area will decrease even if pine is promoted in forestry. The predicted restoration rate ranges from 50 to 72% depending on scenario and previous thinning regime. In conclusion, under the given management concepts and considering today's high proportion of old pine, restoration is alarmingly slow. Amid the rapidly changing climate, we recommend to further adjust the management guidelines to accelerate forest restoration. [ABSTRACT FROM AUTHOR]

Wood ash fertilization remarkably increases tree growth and hence, carbon sequestration in drained boreal peatland forests, particularly in nitrogen (N)-rich Scots pine sites with limited phosphorus (P) and potassium (K). Because ash lacks N, N-deficient ombrotrophic and poor oligotrophic sites are generally considered unsuitable for ash fertilization. In this study, timber production was investigated in six field experiments in N-poor, drained Scots pine dominated peatlands in central Finland, where ash fertilization was applied 15–85 years earlier. Ash significantly increased tree growth in all the study sites. Unfertilized plots showed long-term average mean annual increment (MAI) of 2.01 m3·ha−1·a−1, whereas in fertilized plots MAI was 4.46 m3·ha−1·a−1. An analysis with nonlinear mixed effects model revealed a faster volume yield development and higher asymptote of the mean curve in fertilized plots. Higher amount of K in the ash significantly increased the response. Fertilizations were financially lucrative: on average, the break-even cost surpassed the ash fertilization cost (390 € ha−1) more than two-fold at 5% interest rate. The current nutrient status of fertilized trees was rather balanced. The results proved that the long-term growth response to ash fertilization in poor drained peatland sites is comparable to N-rich sites, but the response time is distinctively longer. [ABSTRACT FROM AUTHOR]

Bird species depending on seeds from masting trees face large temporal and spatial variation in food availability and perform nomadic or irruptive movements to locate food. In northern Europe, the Common Crossbill (Loxia curvirostra) is specialized on seeds from Norway Spruce (Picea abies) which usually has peak years followed by crop failure. Common Crossbills breed in mast years and emigrate when spruce seeds are no longer available. On the other hand, the Parrot Crossbill (L. pytyopsittacus) is specialized on seeds from Scots Pine (Pinus sylvestris) in which seed production is more stable from year to year. The Parrot Crossbill is therefore thought to be more sedentary. However, both species may switch food if there is low abundance of their 'own' seed type, but little is known about the relative importance of crop size of the two tree species on breeding population size and migration of the two crossbill species. Here, we analyse time series (up to 36 years) of crossbills and crop size of spruce and pine in Norway and Sweden to investigate this. We found that breeding population sizes of both species were positively related to spruce crop size. Surprisingly, pine crop size had no positive influence, not even on the Parrot Crossbill. Emigration of both crossbill species (based on autumn migration counts in southern Sweden) increased when there were small seed crops of spruce, but pine crop size had no influence, not even on the Parrot Crossbill. There was no influence of population size on emigration. These results suggest that alternative food resources had an asymmetric effect, only influencing the Parrot Crossbill. This asymmetry explains why the two crossbill species often have synchronous eruptions despite being specialized on different tree species with different seed crop size dynamics. [ABSTRACT FROM AUTHOR]

Close-to-nature forest management combines the economic use of forests with nature conservation in forest, aiming promote stability, productivity, diversity and continuity within forest ecosystems. While close-to-nature management is expected to positively impact the tree growth, its effect on the belowground micro-biota has been poorly investigated. Nematodes and microbes are species-rich and abundant soil microorganisms that have long been used as ecological indicators of soil health. In this study, was assessed the impact of close-to-nature forest management on soil nematode communities and microbial activity in the pine plantations on aeolian sands in Southern Slovakia, 10 years after the introduction of this management approach. Fifteen stands in close-to-nature forest managed and fifteen stands with applying standard forest management were chosen. Our findings revealed that close-to-nature forest management significantly increased the abundance of soil nematodes and nematode biomass in each of the plots. Moreover, close-to-nature forest management significantly increased the mean abundance of omnivores and predators as stress sensitive nematodes (c–p4, c–p5). Additionally, close-to-nature forest management reduces the proportion of stress tolerant nematodes (c–p1) and enrichment opportunists (c–p2), increased all maturity and structure indices as well as composite, structure, predator and omnivore footprints. Furthermore, close-to-nature forest management significantly increased soil moisture, soil carbon content, microbial biomass carbon, basal respiration and N-mineralization, and understory vegetation diversity. These findings suggest that close-to-nature management practice, resulting in forest of different ages, positively influenced nematode communities and microbial activity by changing the quantity and quality of resources associated with increased understory cover and diversity. [ABSTRACT FROM AUTHOR]

The pressure to plant seedlings in unprepared instead of prepared soil in forest regeneration is increasing, although seedlings' growth in unprepared soil is poorer. One way to improve seedlings' growth could be to add arginine phosphate to the planting hole at the time of planting. In field studies, abiotic and biotic damage normally disturbs studies which seek to determine growth effects, especially in unprepared soil. The study's aims were (i) to clarify whether it was possible to investigate the differences between varying soil layer structures mimicking site preparation methods and seedling treatments in simulated planting places in partly controlled conditions; and (ii) to investigate the effects of arginine phosphate (arGrow® Granulat) on the growth, especially root growth, of Norway spruce (Picea abies (L.) H. Karst.) and Scots pine (Pinus sylvestris L.) container seedlings in those simulated planting places. Seedlings of both tree species were planted in 40 l pots sunk partly into the soil in a sandy field. Before planting, pots were filled with soil layers mimicking layers in soil without any site preparation treatment and in spot mounds. After one growing season, the differences in growth parameters between treatments were small in Norway spruce seedlings, and no significant benefits of arginine phosphate were observed. The soil in the spruce pots was fine-textured and contained a thick organic layer. More studies in more common forest soil types suitable for Norway spruce seedlings are needed to be sure about the growth responses. In Scots pine seedlings, adding arginine phosphate granules to the planting holes improved the growth of seedlings at least in the first summer after planting in soil layers mimicking no mechanical site preparation situation, and the growth improvement may even have compensated the mounding effects. In conclusion, mimicking site preparation methods in large pots was a promising method by which the differences between site preparations methods as well as effects of seedling treatments, in our case arginine phosphate, on the growth of conifer seedlings, can be tested. [ABSTRACT FROM AUTHOR]

The influence of meteorological factors and anthropogenic air pollution on the radial growth of the Scots pine Pinus sylvestris L. was studied as dependent on the distance from the Pechenganickel mining and metallurgical plant (Nikel, Murmansk region). Three (control, buffer, and impact) zones of the pollution gradient were identified based on the contents of main polluting elements (S, Ni, and Cu) in the forest litter. A significant weakening of pine stands was observed in the impact zone and attributed to the combined effect of long-term anthropogenic pollution of the 1970s and unfavorable weather events of the mid-1980s. As the emission decreased from 1988 to 2018, the radial increment of P. sylvestris was observed to increase significantly (by up to 44%) in the impact zone and to remain much the same in the control and buffer zones. More recently, the radial increment of trees in the impact zone reached and even exceeded the values observed in the control zone, although the trees examined were relatively old. The finding demonstrated again the high adaptive capacity of P. sylvestris. [ABSTRACT FROM AUTHOR]

Trees affect the biotic and abiotic properties of the soil in which they grow. Tree species-specific effects can persist for a long time, even after the trees have been removed. We investigated to what extent such soil legacies of different tree species may impact tree seedlings in their emergence and growth. We performed a plant–soil feedback experiment, using soil that was conditioned in plots that vary in tree species composition in Białowieża Forest, Poland. Soil was taken from plots varying in proportion of birch, hornbeam, pine, and oak. In each soil, seeds of the same four target species were sown in pots. Seedling emergence and growth were monitored for one growing season. To further explore biotic implications of soil legacies, ectomycorrhizal root tip colonization of oak, a keystone forest species, was determined. We found no effect of soil legacies of tree species on the emergence measures. We, however, found a clear negative effect of pine legacies on the total biomass of all four seedling species. In addition, we found relationships between the presence of pine and soil fertility and between soil fertility and root tip colonization. Root tip colonization was positively correlated with the biomass of oak seedlings. We conclude that tree species can leave legacies that persist after that species has been removed. These legacies influence the growth of the next generation of trees likely via abiotic and biotic pathways. Thus, the choice of species in today's forest may also matter for the structure and composition of future forests. [ABSTRACT FROM AUTHOR]

Tree species diversity in forest ecosystems could reduce their vulnerability to extreme droughts through improved microclimate and below‐ground water source partitioning driven by contrasting species‐specific water use patterns. However, little is known about the seasonal dynamics of belowground water uptake that determine whether diversity positively or negatively impacts tree carbon assimilation and water exchange.Using a network of 30 permanent plots in Mediterranean forests with increasing tree species diversity (from monospecific to four‐species mixtures), we examined the seasonal patterns of in‐situ aboveground carbon and water relations and belowground water sources on 265 trees from four pine and oak species over 2 years using hydraulic and stable isotope approaches.We found that increasing species diversity in broadleaf and conifer mixtures induced strong soil water source partitioning between oak and pine species. As conditions became drier during the summer in mixed stands, oak species took up water from deeper soil sources, while pines were systematically limited to shallow ones. Despite significant belowground moisture partitioning, stronger drought‐induced reductions in photosynthesis, stomatal conductance, and leaf water potential were still observed in diverse compared with monospecific stands for pines but with some benefits for oaks.Synthesis: Our findings reveal that tree species diversity promoted belowground water source partitioning in mixed oak and pine stands, potentially reducing competition for water in more diverse ecosystems. Yet, our results show that it is insufficient to buffer the adverse impacts of severe droughts on aboveground tree carbon and water use, leading to higher water stress, especially for pines. [ABSTRACT FROM AUTHOR]

The distribution of Scots pine (Pinus sylvestris L.) forests, particularly the Vaccinio myrtillo-Pinetum type, is determined by edaphic conditions, and although clear-cutting is used to promote regeneration, it remains controversial. This study evaluated the changes in non-living (forest floor and dead wood) and living (mosses, herbs, and dwarf shrubs) ground cover in clear-cut areas and reforested Scots pine stands. Continuous ground cover studies were conducted in clear-cuts, with samples collected over three years after clear-cutting, while data from 8–80-year-old and mature Scots pine stands were collected using the chronological series method with a consistent methodology in temporary plots. The research has shown that, as ecosystem recovery progresses, similarity to the mature forest increases, and a threshold stand age has been identified, beyond which the ecological changes induced by clear-cutting diminish. The study findings demonstrated that clear-cutting in Pinetum vaccinio-myrtillosum-type forest stands lead to a rapid increase in herb and dwarf shrub cover due to reduced competition for light and nutrients. However, clear-cutting caused a significant decline in forest-specific species and a drastic reduction in forest floor and dead wood mass, with a gradual recovery of moss cover over 10–30 years. These findings highlight the importance of managing clear-cutting practices to balance immediate vegetative responses with long-term ecosystem stability and biodiversity conservation. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.) has higher early growth rates than Norway spruce (Picea abies (L.) H. Karst.). To help efforts to understand possible reasons for this difference and identify appropriate regeneration methods, we labeled seedlings with 15N in the nursery to probe nitrogen (N) uptake and retranslocation in Scots pine and Norway spruce seedlings at both harsh and fertile sites in southern and northern Sweden. For this, 15N dilution was measured during the first two years after planting. We also examined the potential N2-fixation capacity in fine roots after 5–7 growing seasons. Use of 15N-labeled seedlings enabled clear discernment of contributions of uptake of new N and retranslocation of old N to new foliage. Scots pine seedlings had higher proportions of N derived from uptake (Ndfu) than Norway spruce seedlings, and higher growth. Scots pine seedlings were less responsive to site preparation treatments compared to Norway spruce that has a greater need for appropriate silvicultural measures to grow well. After the second growing season, the contribution of N derived from retranslocation (Ndfr) to N in new foliage had diminished to 10–20% at all except the harshest site, where both species were more dependent on Ndfr. The potential N2-fixation capacity in fine roots of the two species differed, but in both cases the contribution of N2-fixation to N-acquisition was negligible. [ABSTRACT FROM AUTHOR]

The pinewood nematode (PWN), Bursaphelenchus xylophilus, is the causal agent of pine wilt disease and is considered an A2 quarantine organism by the European Plant Protection Organisation. In Europe, this nematode has been reported in Pinus pinaster, P. radiata, and P. nigra. In May 2024, severe wilting symptoms were observed in P. sylvestris trees at Serra da Lousã (Coimbra, the central area of continental Portugal). Wood samples were collected from six wilted trees, and the presence of PWN was investigated. From these, B. xylophilus specimens were detected in five out of the six trees. Species identification was performed based on species-specific morphological diagnostic characters, and this was confirmed by real-time PCR using species-specific primers targeting the B. xylophilus satellite DNA region. This study presents the first detection of B. xylophilus in P. sylvestris in Portugal and in Europe. [ABSTRACT FROM AUTHOR]

We studied the recovery of the growth and physiological parameters of Scots pine seedlings after long-term zinc toxicity. The removal of excess zinc from the nutrient solution resulted in the rapid recovery of primary root growth but did not promote the initiation and growth of lateral roots. The recovery of root growth was accompanied by the rapid uptake of manganese, magnesium, and copper. Despite the maximum rate of manganese uptake by the roots, the manganese content in the needles of the recovering plants did not reach control values during the 28 days of the experiment, unlike magnesium, iron, and copper. In general, the recovery of ion homeostasis eliminated all of the negative effects on the photosynthetic pigment content in the needles. However, these changes, along with recovery of the water content in the needles, were not accompanied by an increase in the weight gain of the recovering seedlings compared with that of the Zn-stressed seedlings. The increased accumulation of phenolic compounds in the needles persisted for a long period after excess zinc was removed from the nutrient solution. The decreased lignin content in the roots and needles is a characteristic feature of Zn-stressed plants. Moreover, the removal of excess zinc from the nutrient solution did not lead to an increase in the lignin content in the organs. [ABSTRACT FROM AUTHOR]

Summary: Scots pine is the foundation species of diverse forested ecosystems across Eurasia and displays remarkable ecological breadth, occurring in environments ranging from temperate rainforests to arid tundra margins. Such expansive distributions can be favored by various demographic and adaptive processes and the interactions between them.To understand the impact of neutral and selective forces on genetic structure in Scots pine, we conducted range‐wide population genetic analyses on 2321 trees from 202 populations using genotyping‐by‐sequencing, reconstructed the recent demography of the species and examined signals of genetic adaptation.We found a high and uniform genetic diversity across the entire range (global FST 0.048), no increased genetic load in expanding populations and minor impact of the last glacial maximum on historical population sizes. Genetic‐environmental associations identified only a handful of single‐nucleotide polymorphisms significantly linked to environmental gradients.The results suggest that extensive gene flow is predominantly responsible for the observed genetic patterns in Scots pine. The apparent missing signal of genetic adaptation is likely attributed to the intricate genetic architecture controlling adaptation to multi‐dimensional environments. The panmixia metapopulation of Scots pine offers a good study system for further exploration into how genetic adaptation and plasticity evolve under gene flow and changing environment. See also the Commentary on this article by Duffy, 243: 830–832. [ABSTRACT FROM AUTHOR]

In forests, a significant proportion of the carbon fixed by trees during photosynthesis is transported belowground along the conducting phloem, so variations in phloem anatomy can lead to variations in transport capacity. Phloem conductance at tree level (Ktree) is also affected by tree height. Both the phloem anatomy and the tree size change during ontogeny, and also differ under different environmental conditions. The goal of our work was to identify the main drivers of variation in Ktree in Scots pine trees growing in natural boreal forests. We conducted a phloem anatomical study and calculated Ktree in trees of three age groups growing in different climatic conditions along a latitudinal gradient from south to north. We found that Ktree was maintained at the same level in actively growing pine trees (25–80-years-old) but increased in old-aged trees (180–190-years-old), possibly reflecting the shift in source-sink relationships of aboveground and belowground parts of trees. Trees of the same age group growing in different climatic conditions demonstrated similar values of Ktree due to coordinated changes in the phloem anatomy and the tree height. In general, the negative influence of tree height on Ktree is offset by the positive influence of phloem width (or trunk diameter) and sieve cell diameter. The exception was young trees growing in the transition zone of the northern taiga subzone to the tundra, where Ktree was the highest in its age group and even exceeded Ktree of middle-aged trees. [ABSTRACT FROM AUTHOR]

Understanding needle biomass turnover rates in Scots pine (Pinus sylvestris L.) stands is crucial for modelling forest ecosystem dynamics and nutrient cycling. This study examined needle litterfall and biomass turnover in Scots pine stands of varying ages in temperate forests (western Poland). The research focused on determining how stand age affects needle biomass, litterfall and the associated turnover rates. Data were collected from 20 Scots pine stands aged 26 to 90 years, and needle litterfall was measured and analysed in relation to stand characteristics such as age, density and biomass. The average annual needle litter production of the sampled Scots pine stands was 2008 kg·ha−1·year−1, similar to the values previously reported for this tree species in other temperate forests in Europe. The average needle biomass turnover rate for sampled Scots pine stands was 23.4%. We could not support the hypothesis that this parameter depended on the age of the Scots pine stand. The needle biomass turnover rate showed a positive correlation with crown length and a negative correlation with stand density due to the very weak correlations; however, further research is needed to confirm these relationships. Despite this, the parameter can be used to estimate needle litterfall and can be applicable to conditions corresponding to those of temperate forests in Central and Western Europe. This study also highlights the need for further research on needle biomass turnover in temperate forests to improve the accuracy of carbon and nutrient cycling models. This work contributes to a deeper understanding of the role of needle litterfall in maintaining soil fertility and forest productivity, offering insights into sustainable forest management and conservation strategies. [ABSTRACT FROM AUTHOR]

Scots pine (Pinus sylvestris L.) represents one of the most important commercial coniferous tree species, providing valuable timber. Due to climate change, it is experiencing serious problems in some areas, therefore, finding a suitable substitute for its wood is currently a challenge. In this study, we compared the wood quality of three different non-native pine species and Scots pine growing at the same site to ensure identical growing conditions. Black pine (Pinus nigra J. F. Arnold), a pine species native to Southern Europe, lodgepole pine (Pinus contorta Douglas ex Loudon), and ponderosa pine (Pinus ponderosa Douglas ex C. Lawson) native to North America were compared to Scots pine for selected quantitative (productivity) and qualitative (physical and mechanical) properties. Significant differences between pine species were found in all quantitative dendrometric parameters, except average diameter at breast height. The stand volume ranged from 157 m3 ha−1 for lodgepole pine to 356 m3 ha−1 for Scots pine. For qualitative characteristics, wood density, shrinkage, and compressive strength were used to find differences among species in choosing the best alternative. The highest wood density was obtained for Scots pine (458 kg m−3), followed by black pine with 441 kg m−3. The density of the remaining pine species was significantly lower. Scots pine also exceeded the tested species in compressive strength (44.2 MPa). Lodgepole pine achieved the second highest value (39.3 MPa) but was statistically similar to black pine (36.5 MPa). The tested pine species exhibited similar values in shrinkage, which were statistically insignificant, ranging from 14.3% for lodgepole pine to 15.1% for Scots pine. Based on applications and preferred characteristics, black pine or lodgepole pine could serve as the Scots pine substitute in some areas. And vice versa, ponderosa pine did not attain the Scots pine wood quality. [ABSTRACT FROM AUTHOR]

The Scots Pine Pinus sylvestris is the most widespread tree species in forests of lowland parts of Central and Eastern Europe. In Polish forests, stands dominated by the Scots pine cover almost 60% of the forest area. We analysed the relationship between forest birds and pine trees in an extensive forest complex in north-eastern (NE) Poland. Based on the 20-year-long study, we considered the percentage of broods established on pine trees and the percentage of Scots pine in stands on grouse leks and territory. A total number of over 20 bird species are dependent on the Scots pine trees or stands to locate their nests. Among this group, 11 bird species strongly associated with pine trees were confirmed, and they located at least 90% of broods or nests on pines. The Black Woodpecker Dryocopus martius selects the Scots pine to excavate cavities. Its cavities were regularly used by some species of secondary cavity nesters. In turn, the Common Raven Corvus corax nests were occupied by selected birds of prey. The importance of Scots pine for birds increased with the age of the trees. Old Scots pine trees were chosen by birds that built large nests, placed nests in the tree top, and excavated large cavities. Populations of pine-specialized bird species may be in danger due to the possibility of the Scots pine range moving to the north, which results from global warming. The maintenance of the Scots pine with the modification of the methods of forest regeneration should be included in the Polish forestry's strategies and plans as a critical factor for the care of the population of rare breeding bird species. [ABSTRACT FROM AUTHOR]

A dataset collected from central South Finland was used to investigate the mortality of boreal trees. The mortality rate was found to be the order of three times that predicted by earlier Nordic mortality models, being in the upper range of international literature observations. Small subpopulations of any tree species tend to die out. The mortality of downy birch increases with stand basal area, as well as with stand age. The mortality of Norway spruce and silver birch increases after 100 years, while that of Scots pine is invariant to age. It is suspected that the high mortality of conifers is due to climatic phenomena of anthropogenic origin. As the relative loss rate of basal area is insensitive to stand basal area, the mortality of trees does not strongly regulate thinning practices, but stand-replacing damage can be avoided by retaining a larger timber stock, along with an enhanced proportion of deciduous trees. [ABSTRACT FROM AUTHOR]

The high temperature sensitivity of pine trees in northern Fennoscandia has led to some of the most reliable tree-ring climate reconstructions in the world for the past millennia. However, wood anatomical anomalies that likely reflect temperature-induced reductions in cell wall lignification, the so-called Blue Rings (BRs), have not yet been systematically investigated in trees and shrubs in northern Europe. Here, we present frontier research on the occurrence of BRs in Pinus sylvestris trees and Juniperus communis (L) s.l. shrubs from the upper treeline in northern Norway (69°N) in relation to instrumental temperature data covering the last ca. 150 years. The highest number of BRs was found in 1902, with 96% of Pinus trees and 68% of Juniperus shrubs showing BRs. These corresponded on average to a 42% vs. 27% proportion of the growth ring in 1902 which was less-lignified in Pinus trees and Juniperus shrubs, respectively. Another peak in BRs recorded for 1877 was more pronounced in Pinus trees (88%) than in Juniperus shrubs (36%), with a lower proportion of less lignified rings. We found the lowest monthly sums of growing degree days in June 1902 and August 1877, resulting in more uniform non-lignified BRs in 1902 than in 1877. Prolonged early growing season cooling shortened the growing season in 1902 and resulted in much thinner cell walls in trees and shrubs than in 1877, which was characterized by extended cooling at the end of the growing season. Also, after 1902 BR, Pinus trees exclusively showed no recovery in the mean cell wall thickness in the following year. Our study provides the first evidence for different impacts of early versus late growing season cooling on cell wall lignification in trees and shrubs at the northern treeline. Using the anatomy of BRs, we demonstrated the potential to refine summer cooling event reconstructions at an intra-annual resolution in northern Fennoscandia and beyond.

This study investigated the potential use of Scots pine cones as an alternative raw material to larch wood chips for particle board production. Due to the increasing scarcity of forest resources, exploring alternative raw material for the forest industry has gained importance in in recent years. Particle boards were produced in laboratory conditions by blending industrial wood chips with Scots pine cones in varying proportions (25 %, 50 %, 75 % and 100 %) and usingr urea formaldehyde glue. The adhesice mixture contained 55 % urea formaldehyde glue and 33 % ammonium chloride as a hardener. Te production parameters included a press temperature of 150 °C, a press time was 7 minutes, and a press pressure of 2,4 MPa to 2,6 MPa. The resulting boards had a thickness of 16 mm and a density ranging from 730 kg/m3 to 740 kg/m3. Tests for thickness iswelling, water absorption, , bending strength, modulus of elasticity and tensile strength perpendicular to the surface were conducted. Results showed that the physical and mechanical properties of the boards containing up to 25 % Scots pine cone met the required standards.

Afforestation in mobile sand dunes, mainly occurring in large arid and semi-arid regions of China, is expected to improve plant diversity and ecosystem function through vegetation restoration processes, which in turn modify SOC and associated soil properties. However, there is a limited understanding of how sand-binding vegetation alters topsoil organic carbon (SOC) sequestration through the vegetation-soil coupling mechanism in semi-arid regions. We compared the differences in soil properties, leaf litter traits, root traits and microbial traits of shrublands and after introducing Pinus sylvestris, evaluated the relative influence weights and driving mechanisms of different modules and key factors on SOC in Horqin Sandy Land. The results showed that SOC in Salix gordejevii shrublands and Caragana korshinskii shrublands was significantly higher than that in their mixed shrublands, and introducing P. sylvestris significantly decreased SOC. The hierarchical partitioning analysis indicated that soil properties, root traits, microbial traits and leaf litter traits explained 42.60 %, 30.84 %, 18.60 % and 7.96 % of the variance in SOC, respectively. The contribution of herb root traits to SOC was greater than that of shrub root traits. Multiple regression analysis showed that the introduction of P. sylvestris into shrublands significantly changed the effects of key factors on SOC, mostly negatively. The structural equation model illustrated that soil properties had direct and significant positive effect on SOC, whereas herbal root biomass indirectly affected SOC through soil properties. Our results indicate that the decrease in SOC was due to the change in litter composition after the introduction of P. sylvestris, which reduced the litter quality and slowed the decomposition rate by microorganisms. In addition, P. sylvestris inhibited the growth of herbaceous plants under the canopy and reduced the biomass of herb roots, which directly reduced the available input source of SOC, thus slowed the accumulation of topsoil organic carbon. We present evidence that positive SOC sequestration by the afforestation of shrubs in mobile sand dunes may be weakened by introducing P. sylvestris, which should be considered in future vegetation restoration in sandy areas.

Noise which could be defined as disturbing sound, is becoming a major problem depending with developing technology. Controlling the noise helps raising the quality of life to higher levels. Although the intensity of the noise is not at a level that will affect human health, it should be reduced or eliminated, for better life standart. Due to the adverse effects of the noise level on health; the acoustic properties of living areas require serious consideration. Sound absorption coefficients of the materials used in the interior play an important role in providing sensory comfort depending on the volume. Natural and artificial wood are commonly used materials in interior design, especially in the construction of partition elements. In addition, wood is natural material and it has some important advantages and disadvantages. In this study the sound absorption coefficients of eastern beech and scotch pine trees, which are the most preferred materials in interior design, were investigated. For this pupose, these wood materials were cut superficially and radially according to the intersection directions, then the sample surfaces were varnished with one and two component water-based varnishes that do not contain solvent-based resin. The sound absorption coefficients of the obtained samples were determined by the impedance tube method and the results were compared statistically. It has been investigated that the obtained results could be evaluated statistically within the frequency values, besides, different results could be obtained according to the characteristics of natural wood materials, the direction of intersection and water-based varnish types. According to the findings obtained as a result of the study, it has been suggested that if natural wood material is used indoors, the superficial cross-section of East beech wood should be used according to the direction of intersection, and a two-component varnish should be used according to the varnish type.

The complex action of environmental factors often triggers the biomass formation in forest plantations, which is crucial for carbon balance and environmental monitoring, especially in the context of climate change. In this article, we present data on the aboveground biomass accumulation for black locust and common pine (Pinus sylvestris and Robinia pseudo­acacia) as the two most common forest-forming species in the steppe zone. For this purpose, we propose a reliable approach to monitoring of aboveground forest biomass with combining Sentinel-2 multispectral imaging techniques (with L-band) and biometric processing data from coniferous and deciduous stands obtained from field surveys. We represent the results of field surveys with established indicators of aboveground biomass of forest plantations in the field experiment, which averaged 159.9 ± 9.0 t/ha in the studied region. The biometric indexes obtained from the field experiments were used to develop models for predicting biomass using the remote method. Based on the processing of satellite image data, forest vegetation indices were analysed, among which the NDVI (normalized difference vegetation index) was the best predictor to assess biomass. The multiple regression method was found to be the best for predicting and mapping the aboveground biomass in P. sylvestris and R. pseudoacacia within the studied area (RMSE – 23.46 t/ha). Based on the results obtained, we created a map of the aboveground biomass distribution in black locust and common pine stands within the studied region. We established reliable correlations between biometric parameters (mean diameter at breast height, mean height) and aboveground biomass of stands with indicators of spectral bands in satellite images. This enables us to use the constructed models to estimate the overall productivity of coniferous and deciduous forest stands for large areas.

We tested the effectiveness of the gradual removal of Scots pine (Pinus sylvestris L.) in former plantations of this species in Roztocze National Park (SE Poland) to support the restoration of natural herbaceous flora and forest structure. We compared 0.5-ha study plots subjected to selective removal of pine trees with control plots excluded from any kind of human intervention for half a century. The observed changes in forest floor vegetation in the converted plots showed naturalization towards habitat-specific species. However, differences in the spatial distribution of trees between the treatment and control plots showed no universal pattern and revealed subtle but positive shifts from regular to random or clustered patterns. The mean tree diameters were higher in plots subjected to Scots pine removal, which resulted from the vigorous growth of tree species, consistent with habitat types. We conclude that forest restoration through the removal of planted trees can support the naturalization of former Scots pine plantations in protected areas. However, the selection of an appropriate method and its intensity are of vital importance. Methods that resemble typical management practices, such as selection thinning, are not always the best approach, as they may preserve or even increase the regular distribution of trees. Therefore, for restoration purposes, we recommend testing other methods that increase spatial heterogeneity, including systematic cutting or emulating natural disturbances. In addition, low-intensity thinning may not be sufficient to support the restoration of natural forest floor vegetation and the variability in forest stand structure.

The photosynthetic acclimation of boreal evergreen conifers is controlled by regulatory and photoprotective mechanisms that allow conifers to cope with extreme environmental changes. However, the underlying dynamics of photosystem II (PSII) and photosystem I (PSI) remain unresolved. Here, we investigated the dynamics of PSII and PSI during the spring recovery of photosynthesis in Pinus sylvestris and Picea abies using a combination of chlorophyll a fluorescence, P700 difference absorbance measurements, and quantification of key thylakoid protein abundances. In particular, we derived a new set of PSI quantum yield equations, correcting for the effects of PSI photoinhibition. Using the corrected equations, we found that the seasonal dynamics of PSII and PSI photochemical yields remained largely in balance, despite substantial seasonal changes in the stoichiometry of PSII and PSI core complexes driven by PSI photoinhibition. Similarly, the previously reported seasonal up-regulation of cyclic electron flow was no longer evident, after accounting for PSI photoinhibition. Overall, our results emphasize the importance of considering the dynamics of PSII and PSI to elucidate the seasonal acclimation of photosynthesis in overwintering evergreens. Beyond the scope of conifers, our corrected PSI quantum yields expand the toolkit for future studies aimed at elucidating the dynamic regulation of PSI. [ABSTRACT FROM AUTHOR]

Minimizing the negative effects of harvesting activities on natural regeneration is important for sustainable forest management. Various studies have been conducted on the damages of harvesting activities on remaining stands to improve silvicultural management practices, including studies in Türkiye considering thinning intensity. The aim of this study is to determine the effects of different skidding techniques on sapling vitality in thinned stands at different thinning intensities. The study was conducted in Scots pine (Pinus sylvestris L.) forests in northeastern Türkiye, with similar ecological characteristics but different thinning intensities. The study was conducted in 18 sample plots with three thinning intensities (low, moderate, high), two skidding techniques (cable pulling and manual skidding) and three replications. After the harvesting activities, the root collar diameters and heights of saplings were measured. The damage type of the damaged saplings and the survival classes of the saplings were determined. 26.0% of the saplings in the areas subject to manual skidding and 22.8% of the saplings in the areas suject to cable pulling were damaged. There was a statistically significant correlation between the thinning intensity and damage types (x² = 60.401, df = 3, p < 0.05) and between the thinning intensity and sapling vitality (x² = 18.873, df = 3, p < 0.05). [ABSTRACT FROM AUTHOR]

Accurate knowledge of site conditions and their effects on regeneration establishment is important for selecting the most appropriate tree species and regeneration methods for a given regeneration site. This study examined the response of the first-year field performance of Scots pine (Pinus sylvestris L.), Norway spruce (Picea abies (L.) Karst.) and silver birch (Betula pendula Roth.) seedlings in boreal forests to variables available in open forest and natural resources datasets. Survival, height increment and damage of planted tree seedlings and the success of direct seeding of pine were analysed on a total of 284 plots (1000 m2) in 18 regeneration experiments established in 2020–2022 in southern and central Finland. The height increment of silver birch was higher than that of conifers, while the lowest mortality rate was found for spruce. In the generalised linear mixed models, topographic wetness index, soil texture, site type and growing stock at clearcut explained the species-specific survival and height increment of planted seedlings and the success of pine seeding. Low-cost, open geospatial data effectively provide useful details on the site conditions suitable for diversifying tree species composition in boreal forests instead of monocultures. [ABSTRACT FROM AUTHOR]

Narrower habitat niche at the range margin may reduce the ability of specialized species to adapt to the changing environments and to shift the range. In most of its European range, the Crested Tit (Lophophanes cristatus) inhabits pine forests throughout the year; those forests are important timber production areas for forest industries. We studied the breeding distribution of this species in relation to forest characteristics in (i) the central part of the range in Estonia, where pine areas have undergone large transformations because of peatland drainage for forestry, and (ii) in isolated populations at the southern range margin in East Ukraine, where historical pine forest losses have been substituted with replanting. In Estonia, both the range of forest site types available and occupied by the species was wider than in Ukraine; the birds occupied forests starting from a younger age and reached higher population densities. A preference for natural mature pine stands was found only in the most peripheral and isolated populations in Ukraine. Larger areas of pine forests in Estonia and their higher historical connectivity may be an important factor that has allowed (large) local populations to adapt to the extensive recent transformations in these ecosystems. In contrast, the historical bottlenecks and isolation of suitable forest patches still limit the population in eastern Ukraine, and climatic, economic, and war-related pressures to pine forests are likely to expose these marginal populations to new fluctuations. [ABSTRACT FROM AUTHOR]

Scots pine knotwood contains valuable amount of stilbenoids such as pinosylvin (Ps) and pinosylvin monomethyl ether (PsMME). The stilbenoids have numerous biological activities. Traditional methods of extracting stilbenoids often yield low quantities and involve complex processes. In the present study, a simple and high-yield method was proposed for the extraction of stilbenoids from fresh Scots pine knotwood using ethanol taking a total of three days. In addition, the impact of drying process, extraction time, extraction solvents (acetone and ethanol) and storage time were evaluated on the yield of the stilbenoids. The increased yield and improved extraction efficiency make this method a promising advancement for promoting the utilization of stilbenoids for their valuable bioactive properties. [ABSTRACT FROM AUTHOR]