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Forest health monitoring is crucial for sustainable management, especially with the challenges posed by climate warming. Remote sensing data provide vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), that are widely used in assessing forest health. However, studies considering the validation of these data with field assessments of tree vigor are still scarce. To address this issue, we explored the relationships in declining (D) and non-declining (N) silver fir (Abies alba Mill.) stands from the Spanish Pyrenees between changes in canopy (a proxy of vigor), vegetation indices (NDVI, EVI) and climate variables. We compared trends in the NDVI and EVI for the period of 1984–2023 for D and N stands showing high and low crown defoliation levels, respectively. The EVI values allowed for the separation of stands according to their vigor earlier and more clearly than NDVI values, which did not show clear patterns throughout the time series. Significant negative correlations were found between the EVI and stand defoliation (r = −0.57) or mean radial growth (r = 0.81). Late-spring drought reduced the EVI. The EVI series reflected similar spatial patterns in terms of stand defoliation and tree growth, offering complementary information, along with the strengths of remote sensing with respect to its spatial and temporal coverage, for the early detection of forest dieback. This study also contributes to a better understanding of remote sensing indices, which is useful for forest health monitoring. [ABSTRACT FROM AUTHOR]

Abies nebrodensis is a species of fir endemic to Sicily, represented by only 30 trees in the natural population and is currently classified as critically endangered by IUCN. In such context, monitoring its health status is essential for the proper management and preservation of this species. Phytosanitary surveys of trees of the natural population of A. nebrodensis and on potted plants raised in the local forest nursery were carried out, and the phyllosphere fungal community was investigated. The health condition of trees in the natural population were fairly good, with needle reddening and blight as the most frequently observed symptoms on the foliage, while in the nursery similar disorders were registered on about the 1.3% of potted plants. Results on fungal isolations highlighted the presence of species belonging to Valsa, Cytospora (which includes anamorphs of Valsa) and Rhizosphaera genera as the most represented on both reddened and green needles; these results suggest that these fungi likely live as endophytes, resuming their growth when needles are affected by environmental stressors such as wind, hail, mechanical wounds and do not represent a biotic constraint for A. nebrodensis. The disorders observed appear mostly as a consequence of the harsh site in which the relic species lives. Together with the fungal community observed on symptomatic and healthy needles, they indicate that A. nebrodensis adapted and tolerates its altered habitat. [ABSTRACT FROM AUTHOR]

Summary: It is well established that solar irradiance greatly influences tree metabolism and growth through photosynthesis, but its effects acting through individual climate metrics have not yet been well quantified. Understanding these effects is crucial for assessing the impacts of climate change on forest ecosystems.To describe the effects of solar irradiance on tree growth, we installed 110 automatic dendrometers in two old‐growth mountain forest reserves in Central Europe, performed detailed terrestrial and aerial laser scanning to obtain precise tree profiles, and used these to simulate the sum of solar irradiance received by each tree on a daily basis. Generalized linear mixed‐effect models were applied to simulate the probability of growth and the growth intensity over seven growing seasons.Our results demonstrated various contrasting effects of solar irradiance on the growth of canopy trees. On the one hand, the highest daily growth rates corresponded with the highest solar irradiance potentials (i.e. the longest photoperiod). Intense solar irradiance significantly decreased tree growth, through an increase in the vapor pressure deficit. These effects were consistent for all species but had different magnitude.Tree growth is the most effective on long rainy/cloudy days with low solar irradiance. [ABSTRACT FROM AUTHOR]

Disentangling the factors influencing the climate sensitivity of trees is crucial to understanding the susceptibility of forests to climate change. Reducing tree-to-tree competition and mixing tree species are two strategies often promoted to reduce the drought sensitivity of trees, but it is unclear how effective these measures are in different ecosystems. Here, we studied the growth and physiological responses to climate and severe droughts of silver fir and Douglas-fir growing in pure and mixed conditions at three sites in Switzerland. We used tree-ring width data and carbon (δ13C), oxygen (δ18O) and hydrogen (δ2H) stable isotope ratios from tree-ring cellulose to gain novel information on water relations and the physiology of trees in response to drought and how tree species mixture and competition modulate these responses. We found significant differences in isotope ratios between trees growing in pure and mixed conditions for the two species, although these differences varied between sites, e.g. trees growing in mixed conditions had higher δ13C values and tree-ring width than trees growing in pure conditions for two of the sites. For both species, differences between trees in pure and mixed conditions regarding their sensitivity to temperature, precipitation, climatic water balance and vapor pressure deficit were minor. Furthermore, trees growing in pure and mixed conditions showed similar responses of tree-ring width and isotope ratios to the past severe droughts of 2003, 2015 and 2018. Competition had only a significantly negative effect on δ13C of silver fir, which may suggest a decrease in photosynthesis due to higher competition for light and nutrients. Our study highlights that tree species mixture may have only moderate effects on the radial growth and physiological responses of silver fir and Douglas-fir to climatic conditions and that site condition effects may dominate over mixture effects. [ABSTRACT FROM AUTHOR]

Abstract Background Carbon (C) sink and stock are among the most important ecosystem services provided by forests in climate change mitigation policies. In this context, old-growth forests constitute an essential reference point for the development of close-to-nature silviculture, including C management techniques. Despite their small extent in Europe, temperate old-growth forests are assumed to be among the most prominent in terms of biomass and C stored. However, monitoring and reporting of C stocks is still poorly understood. To better understand the C stock amount and distribution in temperate old-growth forests, we estimated the C stock of two old-growth stands in the Dinaric Alps applying different assessment methods, including direct and indirect approaches (e.g., field measurements and allometric equations vs. IPCC standard methods). This paper presents the quantification and the distribution of C across the five main forest C pools (i.e., aboveground, belowground, deadwood, litter and soil) in the study areas and the differences between the applied methods. Results We report a very prominent C stock in both study areas (507 Mg C ha− 1), concentrated in a few large trees (36% of C in 5% of trees). Moreover, we found significant differences in C stock estimation between direct and indirect methods. Indeed, the latter tended to underestimate or overestimate depending on the pool considered. Conclusions Comparison of our results with previous studies and data collected in European forests highlights the prominence of temperate forests, among which the Dinaric Alps old-growth forests are the largest. These findings provide an important benchmark for the development of future approaches to the management of the European temperate forests. However, further and deeper research on C stock and fluxes in old-growth stands is of prime importance to understand the potential and limits of the climate mitigation role of forests.

Simple Summary: Determining the ecological niche breadth of various organisms is a key objective in contemporary biological research. Studies of this type play a significant role in describing biotic interactions, which is becoming particularly important in the context of observed climate change. A method has been developed that enables the monitoring of the impact of climatic changes at the local level, in specific tree stands. The statistical foundations of the method enable the computation of errors of estimation. The method offers a high precision and explains approximately 80% of the variation in the niche breadth of bark beetles on natural traps, while the mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe—for example—the impact of observed climate change on the population dynamics of bark beetles. The results suggest a need for further research to derive regression equations for firs growing in different regions of Europe. Bark beetles are a significant link in the chain of diseases that lead to the accelerated dying of firs (Abies alba Mill.), a key species in the cultivation of stable mixed-tree stands. The aim of this work was to evaluate biotic interactions in populations of bark beetles that colonised natural traps made from firs. The tested hypothesis was that the niche breadth of the species increases with the increasing density of the population. The research was carried out in near-natural forests containing fir, growing in the Suchedniów-Oblęgorek Landscape Park in central Poland. Data were collected from 30 traps trees and 30 windfalls in the years 2010–2023. Cryphalus piceae Ratz. prefers heavily weakened trees, as shown by the fact that it colonised all of the natural traps, which lack any defensive reactions. The sampling method used in the study proved effective, as confirmed by the segregation of the niches of all of the bark beetles. Using nonlinear regression (linearisable model and piecewise linear regression), models were constructed that describe the niche breadths of the bark beetles. The niche parameter is correlated with the density of colonisation. The derived models explain around 77–84% of the variation in the niche breadth of bark beetles on natural traps. The mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe—for example—the impact of observed climate change on the population dynamics of bark beetles. [ABSTRACT FROM AUTHOR]

Worldwide studies have related recent forest decline and mortality events to warmer temperatures and droughts, as well as pointing out a greater vulnerability to climate changes in larger trees. Previous research performed on silver fir (Abies alba Mill.) suggest an increasing decline and mortality, mainly related to rising water shortages. Here, we investigate these die-off events in two silver fir populations at the rear edge of the species in the western Pyrenees. We used dendrochronology to investigate tree age, size (diameter) and individual climate sensitivity (climate–growth relationships) as predisposing factors related to growth patterns and drought resilience indexes in canopy-level declining and non-declining trees. The regional climate was also investigated, including temperature trends, quantile regression in precipitation and frequency of extreme events in drought indexes (SPEI). The regional climate was characterized by an increase in mean temperatures and a higher frequency of extreme drought events in recent decades, without a decrease in total precipitation. Larger trees were more sensitive to temperature and prone to decline. Declining trees presented decreasing growth trends years ago, providing a robust predisposing trait. Both populations were not different in mean growth, despite the contrasting local climate and management legacies, although we identified a higher resilience to drought in the eastmost stand. A significant regression was found between growth trends and climate sensitivity, supporting that declining trees are more sensitive to warmer temperatures and drought. Hence, the results support a contrasting climate sensitivity related to tree size (but not to tree age), suggesting impending decline and mortality in large trees with higher temperature sensitivity (negative temperature–growth correlations). Nonetheless, contributing factors, such as the legacy of previous logging, should also be accounted for. [ABSTRACT FROM AUTHOR]

For European silver fir (Abies alba (Mill)), reliable threshold values for the sulfur nutritional status are not available. Because European silver fir is an important coniferous tree species in Central Europe and due to the fact that by reduced S emissions, S is becoming a more and more critical nutrient this knowledge gap should be closed. From the interpretation of the cumulative distribution of sulfur concentrations in first‐year needles, the respective threshold values for the range of normal nutrition as well as the threshold for deficiency could be derived. When knowing these thresholds also the range of harmonic nutrition, which is the range for the optimal relation of two nutrients, could be calculated. As compared to the very few literature data available and compared to the respective values of the two most important European conifers Norway spruce (Picea abies) and Scots pine (Pinus sylvestris), the values derived for S nutrition of European silver fir are very reasonable. With respect to the S nutritional thresholds, European silver fir is very close to the values of the other two conifers, whereas the harmonic range of S in relation to N is a bit shifted to higher values indicating that European silver fir has a slightly higher demand for S (in relation to N). There is a certain time lag between the reduction of SO2 emissions in Europe and the reduction of S concentrations in needles, suggesting that S stored in the soil during periods of high emissions is relevant for S nutrition of trees for a longer period of time. [ABSTRACT FROM AUTHOR]

Context: Habitat fragmentation is expected to erode genetic diversity, which instead needs to be preserved for promoting species adaptation to a changing climate. As this expectation has found mixed support in forest trees, consistent results on the genetic consequences of fragmentation requires adequately replicated experimental designs, as well as an explicit assessment of which landscape features, if any, could mitigate its detrimental effects. Objective: Evaluating the role of several landscape attributes in buffering the detrimental effects of fragmentation in two metapopulations of silver fir. Methods: We genotyped 904 silver fir (Abies alba Mill.) trees from 18 local populations forming two metapopulations comparable for size and extension in the Apennines, a Mediterranean mountain range. We identified the signatures left by the fragmentation process on the genetic features of silver fir local populations. After removing potentially confounding effects due to different evolutionary histories, we used a multivariate approach for testing the relative effect of demographic, geographic, environmental and topographic factors on genetic features of both metapopulations. Results: We found comparable signals of the habitat fragmentation impact on the genetic diversity and structure of both investigated metapopulations. Fragmentation effects were less pronounced in the largest local populations (but not the least isolated), located on gentler slopes with higher soil water availability and lower heat exposure. Conclusions: Our results suggest the existence of a set of demographic and environmental factors that could have coherently buffered the detrimental genetic effects of fragmentation in both metapopulations. These findings could be useful to plan landscape restoration for the evolutionary rescue of mixed forests that once characterized Mediterranean mountain ecosystems. [ABSTRACT FROM AUTHOR]

Forest health monitoring is crucial for sustainable management, especially with the challenges posed by climate warming. Remote sensing data provide vegetation indices, such as the Normalized Difference Vegetation Index (NDVI) and Enhanced Vegetation Index (EVI), that are widely used in assessing forest health. However, studies considering the validation of these data with field assessments of tree vigor are still scarce. To address this issue, we explored the relationships in declining (D) and non-declining (N) silver fir (Abies alba Mill.) stands from the Spanish Pyrenees between changes in canopy (a proxy of vigor), vegetation indices (NDVI, EVI) and climate variables. We compared trends in the NDVI and EVI for the period of 1984–2023 for D and N stands showing high and low crown defoliation levels, respectively. The EVI values allowed for the separation of stands according to their vigor earlier and more clearly than NDVI values, which did not show clear patterns throughout the time series. Significant negative correlations were found between the EVI and stand defoliation (r = −0.57) or mean radial growth (r = 0.81). Late-spring drought reduced the EVI. The EVI series reflected similar spatial patterns in terms of stand defoliation and tree growth, offering complementary information, along with the strengths of remote sensing with respect to its spatial and temporal coverage, for the early detection of forest dieback. This study also contributes to a better understanding of remote sensing indices, which is useful for forest health monitoring.

With climate change and the ever-drier climate, the issue of wildfires is becoming increasingly prominent, generating growing interest in the study of wildfires. The majority of the ongoing research is focused on surface wildland fuels with particular emphasis on dead and usually dry fuel. These insights are difficult to transpose to live fuels, particularly to crown fires. The flammability properties of dead and dry forest fuels are of little significance for understanding the onset and spread of crown fires. Hence, research regarding the flammability properties of fresh forest vegetation is very sparse. The same observation applies to crown fires, despite the fact that this type of wildfires is devastating, difficult to suppress, and usually having dramatic consequences. The aim of this paper is to determine how moisture dynamics of live crown samples (terminal parts of basal branches) of two coniferous species, Abies alba and Picea abies, influence their flammability properties. Experiments were performed in an adapted mass loss calorimeter with a custom-made sample holder in order to mimic the scenario of initiation of crown fires (surface to crown fire interface). Tests were performed with heat flux values of 50, 60, and 70 kW/m2 and with different moisture levels. At all heat flux values, the results show an increasing trend for the peak heat release rate when moisture content is reduced. A. alba samples reach higher peak release rates in comparison with P. abies samples. At heat fluxes of 50 kW/m2 and 60 kW/m2, fresh A. alba samples take longer to ignite than the P. abies samples. At the heat flux of 70 kW/m2, for the set of analyzed moisture contents, the ignition time interval for the A. alba samples is shorter than for the P. abies samples. The results of the principal component analysis (PCA) show that variables such as time to ignition (TTI), peak heat release rate (PHRR), and mean heat release rate (mean HRR) best describe the ignitability of the analyzed conifer samples. [ABSTRACT FROM AUTHOR]

The current state of dark coniferous forests on Earth is a bio-indicator of global environmental change, in particular, the process of gradual degradation of tree species of the genera Pine, Spruce and Fir, due to the negative impact of anthropogenic activities, abiotic and biotic factors. The purpose of the study is to establish the symptoms, prevalence and harmfulness of the causative agent of ulcerative tumour-like disease on the shoots and trunks of white fir. The research was conducted on the territory of the forest fund of the Pokuttia Carpathians, in particular, within the branch Kutske forestry of the State Specialised Economic Enterprise "Forests of Ukraine" in the Kosivske forest enterprise. The study uses classical phytopathological and mycological methods, which are used to investigate the aetiology of the disease, analyse typical symptoms (starting from the early stages), and perform microscopy of the affected parts of fir. The symptoms, aetiology, and pathogenesis of white fir ulcer-like disease, which tends to spread, were investigated. A new name for the disease is substantiated, in particular, it is proposed to use the name "ulcerative tumour-like disease" of fir instead of the current name "cancer". It is shown that a typical sign of infection is the development of tumours, which eventually transform into ulcers. It was found that the tumour-like type of lesion prevails on the undergrowth of fir, and on plants of the upper tiers - ulcerative. It is noted that a typical sign of ulcerative tumour-like disease of white fir is also the presence of pathologies such as "witches' broom". It is proposed to remove affected trees with typical signs of infection with ulcerative tumour-like disease to reduce the infectious background, especially during lighting and cleaning, since affected trees are not released from infection. Therefore, assessing the risk of infection of white fir trees with ulcerative tumour-like disease at the level of specific stands and ensuring an appropriate response to potential infection risks is an important part of sustainable forest management. [ABSTRACT FROM AUTHOR]

Temperate forests are undergoing significant transformations due to the influence of climate change, including varying responses of different tree species to increasing temperature and drought severity. To comprehensively understand the full range of growth responses, representative datasets spanning extensive site and climatic gradients are essential. This study utilizes tree‐ring data from 550 sites from the temperate forests of Czechia to assess growth trends of six dominant Central European tree species (European beech, Norway spruce, Scots pine, silver fir, sessile and pedunculate oak) over 1990–2014. By modeling mean growth series for each species and site, and employing principal component analysis, we identified the predominant growth trends. Over the study period, linear growth trends were evident across most sites (56% increasing, 32% decreasing, and 10% neutral). The proportion of sites with stationary positive trends increased from low toward high elevations, whereas the opposite was true for the stationary negative trends. Notably, within the middle range of their distribution (between 500 and 700 m a.s.l.), Norway spruce and European beech exhibited a mix of positive and negative growth trends. While Scots pine growth trends showed no clear elevation‐based pattern, silver fir and oaks displayed consistent positive growth trends regardless of site elevation, indicating resilience to the ongoing warming. We demonstrate divergent growth trajectories across space and among species. These findings are particularly important as recent warming has triggered a gradual shift in the elevation range of optimal growth conditions for most tree species and has also led to a decoupling of growth trends between lowlands and mountain areas. As a result, further future shifts in the elevation range and changes in species diversity of European temperate forests can be expected. [ABSTRACT FROM AUTHOR]

Abstract Key message Abies alba Mill.–Pinus uncinata Ramond. ecotone dynamics are examined along both altitudinal and protection level gradients by combining field inventories and Landsat data. An upward expansion of A. alba to the subalpine belt is observed in the last decades as a result of stand maturation after logging cessation. Context High-mountain forests constitute sensitive locations to monitor the impacts of global change on tree-species composition and ecotone dynamics. In this study, we focus on the Spanish Pyrenees where silver fir (Abies alba Mill.) coexists with mountain pine (Pinus uncinata Ramond.) forming montane-subalpine ecotones. Aims The main goal of this study is to assess the spatiotemporal dynamics of the silver fir–mountain pine ecotone and its underlying driving factors. Methods We reconstructed the spatial distribution and dynamics of the species by combining remote sensing imagery and field plot data from 1989 to 2015, employing support vector machine techniques for image classification. Using variance analysis and mixed effects models, we then analyzed the evolution of basal area and replacement index, a measure of relative change in species composition, over time and altitude range. Additionally, we explored their relationship with site factors and protection level (National Park vs. protection buffer zone). Results Silver fir has expanded its distribution in both the National Park and the protection buffer zone, whereas mountain pine has remained stable. Both species exhibit increased basal area associated with stand maturation and a higher level of protection. The replacement index indicates a rise in silver fir in the understory on North-facing slopes, attributed to stand densification. These findings are particularly noticeable in the area with the highest level of protection. Conclusion The cessation of traditional land uses has led to ongoing stand densification, promoting succession and favoring the increased abundance of silver fir at its uppermost locations, where this species outcompetes mountain pine.

Досліджено сучасний санітарний стан бука лісового (Fagus sylvatica L.), ялиці білої (Abies alba Mill.) та ялини європейської (Picea abies (L.) Karsten) у Національному природному парку "Гуцульщина" та визначено першопричини їх ослаблення, втрати біотичної стійкості і продуктивності. З'ясовано, що сучасні екологічні виклики, зокрема такі як глобальні зміни клімату, антропогенний тиск, атаки шкідників та епіфітотійне поширення збудників інфекційних хвороб, є предикторами вразливості лісів, що призводить до порушення стратегій їхнього збереження і відновлення. Розраховано та проаналізовано середні значення показника санітарного стану за 2022-2023 рр. на підставі детального лісопатологічного обстеження 15 пробних площ, а також ідентифіковано видовий склад патологій інфекційного характеру у деревостанах дослідного регіону. Встановлено, що загальний санітарний стан лісів за участю бука лісового, ялиці білої та ялини європейської, що ростуть в умовах Національного природного парку "Гуцульщина", наразі потрібно вважати ослабленим. Середньозважений показник санітарного стану становить 2,50 з варіюванням від 1,39-3,55 (у 2022 р.) і 1,53-3,52 (у 2023 р.). Спостерігається повільне, проте стійке, збільшення площ розладнаних і загиблих деревостанів. Зафіксовано наявність дерев V і VІ категорій стану, осередки бактеріозу, мікозних хвороб і стовбурових шкідників. Під час обстежень відзначено типову симптоматику бактеріальної водянки ялиці (збудник – фітопатогенна бактерія Lelliottia nimipressuralis (Carter 1945)), раку ялиці (збудник – іржастий гриб Melampsorella cerastii (Pers.) J. Schröt. 1887), нектріозу бука (збудник – гриб-ксилотроф Neonectria ditissima (Tul., & C. Tul.) Samuels & Rossman 2006). Серед комплексу афілофороїдних макроміцетів найбільшу кількість видів зареєстровано на деревах бука європейського, найменшу – на ялиці білій. Найпоширенішою виявилася група ксилотрофних базидіоміцетів, серед яких зареєстровано збудники кореневих і стовбурових гнилей (гриби родів Heterobasidion Bref. 1888 та Armillaria (Fr.) Staude 1857, а також видів Phellinus hartigii (Allesch., & Schnabl) Pat., 1903, Fomitopsis pinicola (Sw.) P. Karst. 1881, Fomes fomentarius (L.) Fr. 1849 та ін). Відзначено, що врахування санітарного стану стає ключовим чинником під час розроблення наукових і практичних рішень для забезпечення стійкості та збереження корінних природних лісів Національного природного парку "Гуцульщина".

Fourier Transform Infrared Spectroscopy (FT-IR) and High-Performance Liquid Chromatography (HPLC) could be applied to study the provenance of wood, specifically the differentiation of wood resources, as well as the identification of chemical compounds that are connected to the changes that occur in wood as a result of drying treatments. To test this hypothesis, the bark of silver fir (Abies alba Mill.) from trees belonging to seven different geographical provenances was studied, using samples dried at three different temperatures (60, 80, and 100 °C). FT-IR spectroscopy revealed different band assignments in the mid-infrared region depending on fir provenances, whereas the vibrational bands of the biomass functional groups tended to shift to lower wavenumbers. Significant differences were identified between the chemical compounds in the bark depending on the provenances. The largest proportion of the total phenolics was represented by the epicatechin gallate, epicatechin, catechin, and procyanidin dimer B1. Exploratory data analysis was performed using principal component analysis (PCA), hierarchical clustering, and Pearson correlations. This allowed a comparative evaluation of the samples and interpret the findings according to the geographical provenances, respectively ecological conditions in the areas of origin, but also the influence of the drying temperatures of the samples on chemical compounds. The precipitation in the areas of origin decreased total phenolics in silver fir bark samples, and total phenolics differed not only due to the geographic provenance, but also due to drying temperature.

In some cases, it is difficult to promote climax tree species in the forest stand composition. In the Czech Republic, silver fir (Abies alba Mill.) is a typical example. This study offers an evaluation of the use of two improving compounds for tree plantations in the initial stage of growth in Central Bohemia. In the experiment, we measured the initial growth performance of a young fir plantation treated with a brassinolide compound (concentration 1 : 100 and 1 : 200) and Bio-Algeen® prior to planting and compared it with control treatment: we assessed height, root collar diameter, vitality and mortality rate during the period 2014-2019. Cumulative mortality rate of the plantation reached 25% at the end of the monitoring period, without any significant differences between variants. Height increment of the variant treated with Bio-Algeen® was significantly (P < 0.05) lower than the growth of brassinolide-treated variants, all treated variants were comparable with the control variant. The plantation underwent a drought-stress period in 2014 and 2015, which resulted in worsened vitality and colour across variants. As a result of the simple economic analysis, the most expensive inputs are planting stock and labour, therefore the price and application of additional substances should not affect decision-making.

Bark beetles are a significant link in the chain of diseases that lead to the accelerated dying of firs (Abies alba Mill.), a key species in the cultivation of stable mixed-tree stands. The aim of this work was to evaluate biotic interactions in populations of bark beetles that colonised natural traps made from firs. The tested hypothesis was that the niche breadth of the species increases with the increasing density of the population. The research was carried out in near-natural forests containing fir, growing in the Suchedniów-Oblęgorek Landscape Park in central Poland. Data were collected from 30 traps trees and 30 windfalls in the years 2010–2023. Cryphalus piceae Ratz. prefers heavily weakened trees, as shown by the fact that it colonised all of the natural traps, which lack any defensive reactions. The sampling method used in the study proved effective, as confirmed by the segregation of the niches of all of the bark beetles. Using nonlinear regression (linearisable model and piecewise linear regression), models were constructed that describe the niche breadths of the bark beetles. The niche parameter is correlated with the density of colonisation. The derived models explain around 77–84% of the variation in the niche breadth of bark beetles on natural traps. The mean relative errors of estimation do not exceed 20%. The niche breadth parameter obtained from the derived regression equations may be used in models that describe—for example—the impact of observed climate change on the population dynamics of bark beetles.

Species-rich mixed silver fir (Abies alba Mill.) forests dominated in the northern Apennines, but climate and, mainly, anthropogenic land use provoked a sharp silver fir decline approximately 5000 years bp. The conservation of the silver fir in this region was mainly due to the establishment of monastic orders that preserved and even planted silver fir for its spiritual and economic value. In 1993, the best silver fir stands were included in the Parco Nazionale delle Foreste Casentinesi (FCNP), Monte Falterona e Campigna, and have been submitted to low-intensive management or strict protection regardless of past land use and cultural history. In this study, we have (1) analyzed the current structure of three silver fir forests that have had different ownership histories and (2) compared the structure of the three Italian forests among them and with two old-growth forests from the Dinaric Alps as a reference of naturalness. The results show that the current structures of the three Italian forests are very different among them and are strictly related to past land use and, mainly, to monastic legacies. Even if the Italian forests have experienced decades of low-intensity management or strict protection, they are currently structurally very different from Dinaric old-growth forests. Developing an old-growth structure in these forests can be very slow and, in some ways, unpredictable. The results also highlight the importance of recognizing protected areas as cultural landscapes that host an important biocultural diversity. The current risk is that by applying almost exclusive biodiversity-centered management and setting difficult or impossible-to-achieve biodiversity goals, total diversity will decrease, and biocultural diversity, the greatest richness of most European parks, will be lost.

Key message: Abies alba Mill.–Pinus uncinata Ramond. ecotone dynamics are examined along both altitudinal and protection level gradients by combining field inventories and Landsat data. An upward expansion of A. alba to the subalpine belt is observed in the last decades as a result of stand maturation after logging cessation. Context: High-mountain forests constitute sensitive locations to monitor the impacts of global change on tree-species composition and ecotone dynamics. In this study, we focus on the Spanish Pyrenees where silver fir (Abies alba Mill.) coexists with mountain pine (Pinus uncinata Ramond.) forming montane-subalpine ecotones. Aims: The main goal of this study is to assess the spatiotemporal dynamics of the silver fir–mountain pine ecotone and its underlying driving factors. Methods: We reconstructed the spatial distribution and dynamics of the species by combining remote sensing imagery and field plot data from 1989 to 2015, employing support vector machine techniques for image classification. Using variance analysis and mixed effects models, we then analyzed the evolution of basal area and replacement index, a measure of relative change in species composition, over time and altitude range. Additionally, we explored their relationship with site factors and protection level (National Park vs. protection buffer zone). Results: Silver fir has expanded its distribution in both the National Park and the protection buffer zone, whereas mountain pine has remained stable. Both species exhibit increased basal area associated with stand maturation and a higher level of protection. The replacement index indicates a rise in silver fir in the understory on North-facing slopes, attributed to stand densification. These findings are particularly noticeable in the area with the highest level of protection. Conclusion: The cessation of traditional land uses has led to ongoing stand densification, promoting succession and favoring the increased abundance of silver fir at its uppermost locations, where this species outcompetes mountain pine. [ABSTRACT FROM AUTHOR]

The character of pure or mixed forest canopies and their litterfalls contribute to different forest-floor properties. These organic layers and also subjacent topsoil were studied at three study sites covered by mixed treatments such as beech–spruce, beech–fir, spruce–fir and two monospecific beech and spruce treatments. The age of the forest stands ranged from 11 to 15 years when sampled. All study sites were used as meadows when afforested; therefore, the forest floors were new, and the A-horizon topsoil properties were not influenced by older humus inherited from previous forest generations. The mineral soil was likely affected by different levels of former fertilization, which resulted in differences among the study sites. The early-developed forest floors showed differences between the treatments with beech and the others. The topsoil below beech with spruce had more nitrogen, oxidizable carbon and cations of exchangeable hydrogen as well as pH showing more acidic conditions and lower contents and saturation of base cations. Pure beech had more phosphorus. The nutrient pools did not differ among the treatments; significantly more matter was found below the oldest stands on the first afforested site, which also increased nutrient pools. [ABSTRACT FROM AUTHOR]

Ongoing climatic change is threatening the survival of drought-sensitive tree species, such as silver fir (Abies alba). Drought-induced dieback had been previously explored in this conifer, although the role played by tree-level genetic diversity and its relationship with growth patterns and soil microsite conditions remained elusive. We used double digest restriction-site-associated DNA sequencing (ddRADseq) to describe different genetic characteristics of five silver fir forests in the Spanish Pyrenees, including declining and non-declining trees. Single nucleotide polymorphisms (SNPs) were used to investigate the relationships between genetics, dieback, intraspecific trait variation (functional dendrophenotypic traits and leaf traits), local bioclimatic conditions, and rhizosphere soil properties. While there were no noticeable genetic differences between declining and non-declining trees, genome–environment associations with selection signatures were abundant, suggesting a strong influence of climate, soil physicochemical properties, and soil microbial diversity on local adaptation. These results provide novel insights into how genetics and diverse environmental factors are interrelated and highlight the need to incorporate genetic data into silver fir forest dieback studies to gain a better understanding of local adaptation. [ABSTRACT FROM AUTHOR]

The increase in the frequency, intensity, and duration of drought periods in recent decades, with a significant impact on the state and functionality of the forest, requires an improvement in understanding the resilience and adaptability of forest species to environmental changes. Based on an extensive network of dendrochronological series from the Eastern Carpathians (150 spruce series, 41 fir series, and 40 beech series) with ages ranging from 30 to 160 years, distributed along an altitudinal gradient (470-1670 m), the resilience to the severe drought of 2003 was assessed. The results obtained, through resilience indices (resistance, recovery, resilience, and recovery period) applied to the mean growth series in basal area increment, suggest a higher resilience to the 2003 drought in beech compared to spruce and fir. Drought resistance increases with altitude, while recovery capacity decreases, especially for beech and spruce. In the case of fir, no significant variation in the resilience index was observed with the altitudinal gradient. Regarding the average cambial age in the year of the extreme climatic event, no statistically significant relationship was found. The research highlighted a high resilience to the 2003 drought among the main forest species in the Eastern Carpathians. In most cases, these species have the capacity to recover to their previous radial growth rates, even though the reduction in auxological processes was relatively large. [ABSTRACT FROM AUTHOR]

In 2021, measurements were done at two international provenance research trials for silver fir originating from the same series of experiments. The investigation was carried out in the location Vítkov and Úsov, where both trials were established. Biometric data (tree height, diameter at breast height) were measured and qualitative traits (stem shape, occurrence of stem forking, stem damage, bark pattern, and defoliation) were assessed during the early mature stage of the experiment. Overbark stem volume and per-hectare standing volume were also calculated. Sixty-five provenances of domestic and foreign origin were evaluated in both trials. Although the results do not indicate unequivocally the most suitable or most productive provenance in the trials, provenances of Czech origin including the ones originating from the surrounding natural forest areas perform consistently better than the average. The least productive provenances, on the other hand, were those from parts of Bulgaria, Austria, and especially Italy, which achieved the poorest results even in stem shape. In Czech conditions, therefore, Italian fir provenances have not proved so successful as they have in the United Kingdom.

Central European populations of silver fir (Abies alba Mill.) grow under a relatively wide amplitude of environmental conditions. Assuming that forest tree stands are locally adapted, the use of forest reproductive material from sites with limited water availability is expected to increase drought tolerance in future forests. At the same time, genetic diversity is of utmost importance as the basis of adaptation to a changing environment. Currently, a selection of potential sources for climate-smart reproductive material of silver fir is under way in Southern Germany. It is based on a multidisciplinary approach elucidating the genetic variation, site conditions, as well as tree resilience based on a dendroecological approach. The analysis encompasses a large number of stands representing the whole range of the species’ ecological requirements. The population genetic analysis based on molecular markers (nuclear microsatellites) provided important information concerning the gene pool of the species in Southern Germany. On one hand, it revealed genetic differentiation and transition zones between western and eastern clusters. On the other hand, the results indicated gradients and regional variation of genetic diversity. These patterns can be explained by post glacial recolonization and the peripheral character of the species at the northern limit of its distribution. Together with the outcomes of the site condition and dendroecological approaches, the results of the genetic analysis will be used to inform future provenance recommendations.

In some cases, it is difficult to promote climax tree species in the forest stand composition. In the Czech Republic, silver fir (Abies alba Mill.) is a typical example. This study offers an evaluation of the use of two improving compounds for tree plantations in the initial stage of growth in Central Bohemia. In the experiment, we measured the initial growth performance of a young fir plantation treated with a brassinolide compound (concentration 1 : 100 and 1 : 200) and Bio-Algeen® prior to planting and compared it with control treatment: we assessed height, root collar diameter, vitality and mortality rate during the period 2014-2019. Cumulative mortality rate of the plantation reached 25% at the end of the monitoring period, without any significant differences between variants. Height increment of the variant treated with Bio-Algeen® was significantly (P < 0.05) lower than the growth of brassinolide-treated variants, all treated variants were comparable with the control variant. The plantation underwent a drought-stress period in 2014 and 2015, which resulted in worsened vitality and colour across variants. As a result of the simple economic analysis, the most expensive inputs are planting stock and labour, therefore the price and application of additional substances should not affect decision-making. [ABSTRACT FROM AUTHOR]

The current study is a dendroarchaeological/dendroarchitectural investigation of the remains of a historically important multi-phase building, nicknamed 'Enetiko', located in Nafplio. Timber was used for the floors, the roof, and timber-framed walls of the building. Timber elements were also embedded in masonry. Particularly important are the architraves; ground storey timber lintels on the southern façade. According to prior research, the earliest phase was thought to date to the early 18th century with a later 19th century modification. Therefore, we applied dendrochronology to check whether it represents an early construction phase of the building and to confirm the previously mentioned different phases. Timber examination revealed six tree species and 60% of the 85 samples collected in total were dated. Imported deciduous oaks (Quercus spp.), dated c.1530 or after, represent an early Venetian or Ottoman phase of the building. Turkish origin of oaks suggests Ottoman period. Imported fir, most likely Abies alba, was dated in the 17th and 18th centuries. Black pine (Pinus nigra) from Greece and juniper (Juniperus sp.) from the East were used in interventions of the late 19th and 20th centuries. [ABSTRACT FROM AUTHOR]

Silver fir (Abies alba Mill.) is a keystone conifer of European montane forest ecosystems that has experienced large fluctuations in population size during during the Quaternary and, more recently, due to land-use change. To forecast the species' future distribution and survival, it is important to investigate the genetic basis of adaptation to environmental change, notably to extreme events. For this purpose, we here provide a first draft genome assembly and annotation of the silver fir genome, established through a community-based initiative. DNA obtained from haploid megagametophyte and diploid needle tissue was used to construct and sequence Illumina paired-end and mate-pair libraries, respectively, to high depth. The assembled A. alba genome sequence accounted for over 37 million scaffolds corresponding to 18.16 Gb, with a scaffold N50 of 14,051 bp. Despite the fragmented nature of the assembly, a total of 50,757 full-length genes were functionally annotated in the nuclear genome. The chloroplast genome was also assembled into a single scaffold (120,908 bp) that shows a high collinearity with both the A. koreana and A. sibirica complete chloroplast genomes. This first genome assembly of silver fir is an important genomic resource that is now publicly available in support of a new generation of research. By genome-enabling this important conifer, this resource will open the gate for new research and more precise genetic monitoring of European silver fir forests.

Vegetation landscape dynamics are derived from the relationships established between anthropic activities and climate conditions over time. Paleoenvironmental research in the Pyrenees range (north-eastern Iberian Peninsula) has revealed what these dynamics were like in some regions during the Holocene. However, some fields of biogeography still present questions that need to be addressed, such as the patterns of Fagus sylvatica and Abies alba and the importance of the fire regime during the Meghalayan (late Holocene). We present a multiproxy study performed in a sedimentary record from the Clots de Rialba peat bog, located at 2093 m a. s. l. (Lleida, southern slope of the Pyrenees mountain range), that covers the last c. 3500 years. Analyses were performed on the organic matter content, pollen, non-pollen palynomorphs, and sedimentary charcoals larger than 150 μm. The palynological spectra revealed a maximum extension of Abies alba at about 3500 cal yr BP in the Bronze Age, while Fagus sylvatica showed its maximum extent between 3300 and 2800 cal yr BP. A dominance of Pinus was detected throughout the studied period. Other taxa such as cereals, herbaceous plants, aquatic plants, and coprophilous fungi have also been discussed to identify anthropic pressure and climate pulses. In addition, the study of sedimentary charcoals reveals the main forest fire episodes and their recurrences, some of them linked to anthropogenic activities and/or climate variations. These anthropogenic activities would include the use of opening and maintaining forest fires in deforestation in order to obtain pastures and spaces dedicated to cereal agriculture and the appearance of some taxa linked to or introduced by human communities. [ABSTRACT FROM AUTHOR]

The chemical content of essential oils (EO) obtained from the leaves of four Pinaceae (Abies alba, Picea abies, Pinus cembra and Pinus mugo) was investigated by SPME-GC-MS technique. The vapor phase was characterized by the monoterpenes with values higher than 95.0%. Among them, α-pinene (24.7–48.5%), limonene (17.2–33.1%) and β-myrcene (9.2–27.8%) were the most abundant. The monoterpenic fraction prevailed over the sesquiterpenic one (≥74.7%) in the EO liquid phase. Limonene was the major compound in A. alba (30.4%), P. abies (20.3%) and P. mugo (78.5%), while α-pinene in P. cembra (36.2%). Regarding the phytotoxic properties, EOs were studied at different doses (2–100 μL) and concentrations (2–20/100 μL/mL). All EOs were found to be significantly active (p-value ˂ 0.05) against the two recipient species in a dose-dependent way. In pre-emergence tests, germination of Lolium multiflorum and Sinapis alba was reduced by up to 62–66% and 65–82%, respectively, as well as their growth by up to 60–74% and 65–67%, due to the effects of compounds in both the vapor and liquid phases. In post-emergence conditions, at the highest concentration, the phytotoxicity of EOs caused heavy symptoms and, in the case of S. alba, A. alba EO completely destroyed (100%) the treated seedlings. [ABSTRACT FROM AUTHOR]

Browsing by ungulates can affect the development of a forest stand due to selective browsing and shifts in the growth ranking between tree species. Assessing browsing impact in an objective way is difficult in patchily distributed beech forests. In systematically arranged plots near Kirchberg, Switzerland, the height increment of the two saplings nearest to the plot center (k-tree method) was measured for each height class and tree species, and the within-tree browsing intensity and damage frequency were assessed. In total, 21 tree species were found. Browsing was particularly frequent in climate-adapted species. Winter browsing was more frequent than summer browsing, which was also true for deciduous species, and it significantly reduced height growth. Former damage along the main stem further reduced upgrowth. Browsing shifted the height increment ratio in favor of Fagus sylvatica. Many winter-browsed saplings of Abies alba, Fagus sylvatica, Acer pseudoplatanus, Fraxinus excelsior and Prunus avium had no new leader shoot by the end of the next growing season, i.e., browsing had a long-lasting impact. For estimating browsing impact, it is thus important to assess delays in the response after browsing. Foresters could easily apply the k-tree method in autumn for effective assessments of browsing impact. [ABSTRACT FROM AUTHOR]

In 2021, measurements were done at two international provenance research trials for silver fir originating from the same series of experiments. The investigation was carried out in the location Vítkov and Úsov, where both trials were established. Biometric data (tree height, diameter at breast height) were measured and qualitative traits (stem shape, occurrence of stem forking, stem damage, bark pattern, and defoliation) were assessed during the early mature stage of the experiment. Overbark stem volume and per-hectare standing volume were also calculated. Sixty-five provenances of domestic and foreign origin were evaluated in both trials. Although the results do not indicate unequivocally the most suitable or most productive provenance in the trials, provenances of Czech origin including the ones originating from the surrounding natural forest areas perform consistently better than the average. The least productive provenances, on the other hand, were those from parts of Bulgaria, Austria, and especially Italy, which achieved the poorest results even in stem shape. In Czech conditions, therefore, Italian fir provenances have not proved so successful as they have in the United Kingdom. [ABSTRACT FROM AUTHOR]

The main objective of our study was to investigate the possible differences in the chemical composition of extractives from the bark of silver fir (Abies alba) with respect to the location of the bark sample on the tree, viz. differences in extract composition between stem bark and branch bark samples. Extractives in the bark samples from branches, depending on the distance of the sample from the trunk, were also analysed, and the stem bark samples were analysed with respect to their inner and outer parts. The results of the chemical analysis of extractives were supported by information about their antifungal and antioxidant effects. After felling and sampling silver fir trees, the collected bark samples were ground and freeze-dried. Extraction of bark samples was followed by a system of accelerated extraction using only water as a solvent. The extracts were analysed chemically using gravimetry, spectrophotometry and chromatography. Free-radical-scavenging activity was measured using the DPPH method, and the antifungal effect towards three moulds and three wood-decaying fungi was investigated with antifungal assay using the agar well diffusion method. It was found that the moisture content in bark samples decreased intensively just after the bark samples were peeled off the stem. Detailed chromatographic analysis showed that the bark extracts contained 14 compounds, among which phenolic acids, flavonoids and lignans were found to be the characteristic ones. The content of hydrophilic extractives in the branch bark samples decreased with increasing distance of the sample location from the tree stem. The largest amounts of phenolic extractives were measured in stem bark, followed by branch bark sampled at the point at which the branch entered the tree. Analysis of the separated parts of the bark showed that the outer layers of stem bark contained larger amounts of phenolic extractives, as well catechin and epicatechin, compared to the inner layers. Concentrated extracts of branch bark showed the largest free-radical-scavenging activity among the investigated samples, while strong antifungal effects of the bark extract were not found. [ABSTRACT FROM AUTHOR]

Polydrusus aeratus Gravenhorst, 1807 is a pest of both coniferous and deciduous trees in forests. It is widespread throughout the Czech Republic from the lowlands to the mountains. Adult beetles occur from April to September. In the western Czech Republic, a number of 1- to 2-m tall Abies alba were recently damaged by P. aeratus adults at an altitude of 750 m. P. aeratus can damage older saplings that were damaged as young saplings by the pine weevil. The damage caused by P. aeratus is so for rather small but should not be neglected by foresters. As the ongoing climate change modifies the relationship between trees and pests, also currently indifferent species may become dangerous for forests in near feature. Therefore, scientists would focus also on relatively less dangerous species of pests, especially insects. Possible methods for controlling of P. aeratus are suggested as main output of the study.

Grand fir (Abies grandis/Dougl. ex D. Don/Lindl.) represents the North American species that has the potential to replace and complement to some extent several commercial European species, in particular, Norway spruce and silver fir. This is not only due to its high production potential but also because of its favorable effect on the soil compared to spruce or pine. We tested sample trees from these tree species growing in the same location for physical and mechanical wood properties and evaluated the effect of the thermal treatment (180 °C and 200 °C) on their wood. Wood density, swelling, surface properties, strength, and stiffness were the properties used to find the differences among species. Grand fir obtained higher values for density and compressive strength compared to silver fir. For the remaining properties, these tree species are comparable, except for toughness, which was significantly lower for grand fir. Grand fir wood was even comparable with Norway spruce in the case of density and compressive strength. The thermal treatment resulted in a decrease in density, swelling, wettability, modulus of rupture, and toughness while increasing compressive strength. The effect of the thermal treatment was similar for all tested species. From this perspective, grand fir represents a potential substitute for the timber of endangered European commercial conifers. [ABSTRACT FROM AUTHOR]

Oxygen (δ 18 O) and hydrogen (δ 2 H) stable isotope ratios are tightly coupled in precipitation and, albeit damped, in leaf water, but are often decoupled in tree-ring cellulose. The environmental and physiological conditions in which this decoupling occurs are not yet well understood. We investigated the relationships between δ 18 O and δ 2 H and tree-ring width (TRW), tree crown volume, tree age and climate in silver fir and Douglas-fir and found substantial differences between δ 18 O and δ 2 H. Overall, δ 18 O-δ 2 H correlations were weak to absent but became significantly negative under high summer vapour pressure deficit (VPD). δ 18 O and δ 2 H had positive and negative nonlinear relationships with TRW, respectively, with clear relationships at the site and tree levels for silver fir and, to a lesser extent, for Douglas-fir. Age trends for silver fir were weakly negative in δ 18 O but positive in δ 2 H. Tree crown volume and δ 18 O or δ 2 H had no significant relationships. Most strikingly, δ 18 O strongly depended on spring climate (precipitation and VPD), whereas δ 2 H depended on summer climate (temperature and VPD) for both species. Our study shows that the δ 18 O-δ 2 H decoupling in tree-ring cellulose in two temperate conifer species could be highlighted by their contrasting relationships to climate and tree intrinsic variables (TRW, age)., (© 2024 The Author(s). Plant, Cell & Environment published by John Wiley & Sons Ltd.)

This research aimed to study phytocoenological characteristics of a fir-dominated community on silicate substrate at the locality of Sitnica on Manjača Mt, northwestern Bosnia and Herzegovina. This community originated from artificially forested mixed stands of fir and spruce planted in the habitat of the mountain Dinaric fir-beech forest, over a hundred years ago. With regular selective cuttings and natural regeneration, the structure shifted from even-aged to uneven-aged. In total, 18 phytocoenological relevés were made using the Braun-Blanquet method during the vegetation seasons of 2021 and 2022. Relevés were stored in Turboveg database. Ecological factors were calculated based on Ellenberg bioindicator values. Species composition was analyzed in terms of life form, geoelements and chorotypes. Our analysis indicates that collected relevés can be classified as the association Galio rotundifolii- Abietetum albae belonging to the alliance Fagion sylvaticae.

Antioxidant and antifungal activities of three essential oils (EOs): Melaleuca ericifolia Smith (rosalina; REO), Melaleuca quinquenervia (niaouli; NEO) and Abies alba (fir; FEO) were determined. The antioxidant capacity was investigated by the 2,2-diphenyl-1-picrylhydrazyl (DPPH) assay, and the disc diffusion method was applied to evaluate their antifungal efficacy (in four concentrations 62.5 μL/L, 125 μL/L, 250 μL/L, 500 μL/L used) against Penicillium (P.) expansum microscopic filamentous fungus isolated from bread samples. From the findings it can be clearly evident that antioxidant activities of the EOs were very weak with values ranging from 25.81 ± 7.8 TEAC (6.2 ± 1.4%; FEO) to 162.0 ± 2.1 TEAC (15.9 ± 0.4%; NEO). Regarding antifungal properties, our results revealed that the effects of the EOs on P. expansum growth inhibition were dose-dependent, and they were proportionally increased with increasing EOs concentrations. Detected inhibition zones ranged from 0.00 ± 0.00 mm (for all EOs at 62.5 μL/L) to 11.67 ± 1.15 mm (for REO at 500 μL/L). In conclusion, all analyzed EOs possess promising in vitro antifungal activity (despite their weak antioxidant capacity) suggesting their use as a promising natural preservative in the food industry.

Ongoing climatic change is threatening the survival of drought-sensitive tree species, such as silver fir (Abies alba). Drought-induced dieback had been previously explored in this conifer, although the role played by tree-level genetic diversity and its relationship with growth patterns and soil microsite conditions remained elusive. We used double digest restriction-site-associated DNA sequencing (ddRADseq) to describe different genetic characteristics of five silver fir forests in the Spanish Pyrenees, including declining and non-declining trees. Single nucleotide polymorphisms (SNPs) were used to investigate the relationships between genetics, dieback, intraspecific trait variation (functional dendrophenotypic traits and leaf traits), local bioclimatic conditions, and rhizosphere soil properties. While there were no noticeable genetic differences between declining and non-declining trees, genome–environment associations with selection signatures were abundant, suggesting a strong influence of climate, soil physicochemical properties, and soil microbial diversity on local adaptation. These results provide novel insights into how genetics and diverse environmental factors are interrelated and highlight the need to incorporate genetic data into silver fir forest dieback studies to gain a better understanding of local adaptation.

The geographical and ecological features of Transylvania enable the wide ethnobotanical use of pine species. The aim of this study was to survey the current ethnomedicinal and other traditional use of pine species of Hungarian-speaking ethnic groups in Transylvania and to compare them with earlier reports performed in Transylvania and from other countries related to the Carpathian Basin. Information on pine species was obtained using semi-structured interviews with 515 Transylvanian informants from 18 villages in the period 2007–2019. The young shoots of Abies alba Mill., Picea abies (L.) H. Karst., Pinus nigra J. F. Arnold, and Pinus sylvestris L. were applied to treat respiratory diseases, while the resin was used for dental problems. Syrup and decoction were made from the cones of all species, except Abies alba. Picea abies was the most frequently documented with seven preparations from different parts (even needles), and this species was mentioned in the treatment of 21 diseases. The least recorded was Abies alba, which was applied for coughs and decayed teeth. We recorded the use of the cones and needles of Picea abies for dyspnoea, thyroid glands, and kidney disorders, previously unknown in ethnomedicinal literature. Our data on the pine species confirm their current use and significance in Transylvania. [ABSTRACT FROM AUTHOR]

It is found that the existing problem of wood resources can be partially solved by attracting additional reserves, in particular, stump-root wood (SRW). In order to apply SRW in woodworking and to fill the scientific base with indicators of the macro- and microstructures of the stump-root systems of individual species, studies were carried out on the main characteristics that are decisive for using composite materials in the industrial production. Based on the study results, it was found that there are differences in the internal structure between SRW and stemwood (SW). It was found that in all species, the width of annual rings in the SRW was greater than that in the SW, in particular, in pine (Pinus sylvestris L.) – by 84.62%; in spruce (Picea abies Karst.) – by 73.68%; in fir (Abies alba) – by 93.75%; in aspen (Populus tremula L.) – by 35.71% and in birch (Betula pendula Roth.) – by 105.00%. It has been found that the content of late wood in the SRW of coniferous tree species is less than that in the SW, on average by 20–25%, and the number of annual rings per 1 cm in the SRW is 40–52% less than in the SW. Differences in the microscopic structure between SRW and SW are revealed, which consist in the difference in the size of tracheids in softwoods and of vessels and fibres of libriform in hardwoods. It was found that the transverse dimensions of early tracheids in the SRW were larger than in the SW, in particular, in the radial direction by 19–33% and in the tangential direction by no more than 15%, and the interval of dimensions in the radial direction was 1.5–2.5. It was found that the early tracheids of root wood had thinner walls (by 19–28%) and a larger internal cavity (by 15–25%) compared to similar elements of SW. It was revealed that the diameters of vessels and fibres of libriform in SRW are greater than in SW, in particular, in aspen (Populus tremula L.) – by 20.41% for vessels and by 12.95% for libriform fibres and in birch (Betula pendula Roth.) – by 20.69% for vessels and by 18.41% for libriform fibres. The practical significance of the studies lies in the fact that the obtained characteristics of the structural components of the SRW can be used to predict the strength indicators of composite materials. [ABSTRACT FROM AUTHOR]

This study focuses on the analysis of wood charcoal from Cova del Vidre (Roquetes, Tarragona, Spain). This cave, located at an altitude of 1000 m a.s.l., is a key site for understanding the transition from hunting and gathering to farming in a mountainous region of north-eastern Iberia so far unexplored by archaeobotany. The anthracological study is based on four archaeological levels from the Epipalaeolithic to the Early Neolithic dated between 12.9 and 6.8 kyr cal BP, that is, from the Late Glacial period to the Middle Holocene. During the Younger Dryas, the record is dominated by a little varied spectrum of cryophilous pines (Pinus tp. sylvestris) and thorny shrubs revealing an open landscape where Prunus may prefigure the spread of temperate taxa. In the Early Holocene, a significant change in temperature and precipitation is evidenced, which promoted successional changes in plant communities, with a decline of pine and the sudden rise of temperate/Mediterranean taxa, such as Prunus and Quercus coccifera/ilex. During the Middle Holocene, other temperate taxa appear, such as Quercus deciduous, Buxus sempervirens and Taxus baccata, with yew finally dominating the anthracological record. The appearance and early development of temperate or Mediterranean species as early as the Younger Dryas and the Early Holocene periods, in a mountain context that had long been favourable for Scots pine, allows us to argue the local existence of a glacial refugium. Differences with the nearby sites in the lowlands demonstrate that altitudinal differences in vegetation were already established in the Holocene. Furthermore, the site helps to define the palaeodistribution of Taxus baccata, Abies alba and Fagus sylvatica in southern Europe. [ABSTRACT FROM AUTHOR]

Phenotypic differentiation of Abies alba was identified among selected provenances originating from the northern edge of this species' natural geographic range. We posited that although the seed sources of the study populations were not geographically distant, progenies would differ with respect to growth, needle pigment concentration, and values of photochemical parameters in response to contrasting light conditions. Potted seedlings of six provenances were grown for two seasons under low light (LL, 40% of full irradiance) or high light (HL, 100% of full irradiance). The results showed that the provenances differed in diameter at root collar (DRC) and in relative growth rates of height (RGR). Seedlings grown in full light had a greater mean value of DRC than those in LL. LL increased total needle chlorophyll (Chltot) and carotenoid concentrations compared with HL, and Chltot was modified by the provenance of the seedlings. The provenance "Syców", localized at the northern limit of the species range, showed the lowest value of maximal electron transfer rate (ETRmax) and lower values of growth parameters compared with the other study provenances. Relative growth rate, Chltot, and non-photochemical quenching of fluorescence (NPQ) were correlated with some climatic characteristics of seed stands and formed clusters indicating the local adaptation of the study populations. These results provide evidence of low intraspecific A. alba differentiation in terms of growth dynamics, photochemical capacity, and tolerance to different light regimes. The intraspecific diversity found in our study among the northern lead populations could be, however, important for the natural expansion of this species further north and for the selection of provenances to be used in the programme of the A. alba restoration in the Sudety Mountains, southern Poland, where decline of this species has been observed. [ABSTRACT FROM AUTHOR]

Rear-edge populations at the xeric distribution limit of tree species are particularly vulnerable to forest dieback triggered by drought. This is the case of silver fir (Abies alba) forests located in Southwestern Europe. While silver fir drought-induced dieback patterns have been previously explored, information on the role played by nutritional impairment is lacking despite its potential interactions with tree carbon-water balances. We performed a comparative analysis of radial growth, intrinsic water-use efficiency (iWUE), oxygen isotopes (d18O) and nutrient concentrations in leaves of declining (DD) and non-declining (ND) trees in silver fir in four forests in the Spanish Pyrenees. We also evaluated the relationships among dieback predisposition, intraspecific trait variation (wood density and leaf traits) and rhizosphere soil physical-chemical properties. The onset of growth decline in DD trees occurred more than two decades ago, and they subsequently showed low growth resilience against droughts. The DD trees presented consistently lower foliar concentrations of nutrients such as P, K, Cu and Ni than ND trees. The strong effects of foliar nutrient status on growth resilience indices support the key role played by mineral nutrition in tree functioning and growth before, during and after drought. In contrast, variability in wood density and leaf morphological traits, as well as soil properties, showed weak relationships with tree nutritional status and drought performance. At the low elevation, warmer sites, DD trees showed stronger climate-growth relationships and lower d18O than ND trees. The uncoupling between iWUE and d18O, together with the positive correlations between P and K leaf concentrations and d18O, point to deeper soil/bedrock water sources and vertical decoupling between nutrient and water uptake in DD trees. This study provides novel insights into the mechanisms driving silver fir dieback and highlights the need to incorporate tree nutrition into forest dieback studies. [ABSTRACT FROM AUTHOR]

In the context of global warning, sustainable development, bioeconomy and circular economy, it is of great interest to find better valorizations of by-products of the wood processing industry. The aims of this study were to investigate the effects of the longitudinal position on the stem and of the silviculture on bark chemical composition of three softwood species used in wood industry. Bark was sampled at three different heights (top, middle and bottom) on the trunk of four trees of Picea abies, Abies alba and Pseudotsuga menziesii grown under different silvicultural treatments and subjected to analytical procedures to determine holocellulose, lignin, suberin, hemicelluloses, α-cellulose, ash and extractives contents. Contents of the different polymers tend in general to decrease slightly with tree height, while extractives content increased with height. These results were explained by higher amount of outer bark at the bottom of the trunk containing more polymerized materials and more unpolymerized free sugars in the young tissues at the top of trunk. The effect of the silvicultural treatment has been more difficult to characterize. Chemical composition of the bark differs slightly according to the position of sampling along the trunk. Suberin content is particularly important at the bottom of P. menziesii trees. [ABSTRACT FROM AUTHOR]

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