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The article presents the results of the search for microsatellite or simple sequence repeat (SSR) loci with tri-, tetra-, penta- and hexanucleotide tandem repeat motifs in the draft de novo assembly of the Siberian fir (Abies sibirica Ledeb.) genome and the development of convenient relatively highly and moderately polymorphic markers that can be easily genotyped even by simple gel electrophoresis. In total, 64 pairs of oligonucleotide polymerase chain reaction (PCR) primers for 32 detected microsatellite loci were designed and tested. Based on the testing results, 10 most promising polymorphic loci were selected and genotyped in eight natural populations of Siberian fir. Homologous microsatellite loci in the genome of European silver fir (Abies alba Mill.) were also identified by mapping Siberian fir contigs, containing SSR loci to the European silver fir genome assembly. A multiplex panel of 14 universal microsatellite loci was developed and genotyped in samples from four natural populations of A. alba and a small sample of eight Nordmann fir (Abies nordmanniana (Steven) Spach) trees. [ABSTRACT FROM AUTHOR]

Norway spruce Picea abies is one of Europe's most economically important tree species. However, it is highly susceptible to the root rot fungus Heterobasidion parviporum. Climate change will benefit the pathogen as the tree host is weakened by, e.g., extended drought. Breeding can improve forest health, and several root rot genetic markers are suggested to improve the resistance of Norway spruce. This study aimed to compare the resistance (here defined as necrosis length) of Norway spruce families and genotypes against two strains of H. parviporum under different water availabilities. Our results show that the family and the genotype within the family have an impact on the necrosis length that is related to the aggressiveness of the fungal strains. Under low water conditions, the necrosis increased only in horizontal directions in phloem and sapwood. Similarly, the growth (seedling height) was not disturbed by abiotic stress (less water), indicating that the stress level (drought) was too low in this setting. The knowledge gained in this study could improve forest health in the changing climate by understanding the response of Norway spruce to pathogenic attacks under additional stress at the family level. This knowledge could be strategically used in forest breeding to improve the resistance of Norway spruce trees against root rot. [ABSTRACT FROM AUTHOR]

We analyzed growth trajectories recorded in the tree-ring series of Norway spruce Picea abies (L.) H. Karst. and silver fir Abies alba Mill. co-occuring with European beech Fagus sylvatica L. in old-growth forests driven by natural stand dynamics. The study sites were localized in five old-growth stands in the Western Carpathians (Central Europe). We characterized the life histories of 218 individual trees by using 25 metrics which refer to the age of the trees, number of release events, reaction to releases, radial increment and basal area increment. We found a large variation in the dbh-age relationship. The life histories of most trees included two or three (in single cases up to seven) release events. We did not find tree age as an important factor in determining post-release growth response. The maximal basal area increment was frequently registered at the terminal stage of tree life. The life histories of spruces and firs did not significantly differ. We concluded that in natural forests driven by gap-phase dynamics, the history of release events is the primary driver of tree growth and that tree age plays a secondary role. After reaching the overstory, trees can continue growing without significant symptoms of aging until extrinsic forces cause their death. Our results indicate that in the studied ecosystem the persistence of less shade-tolerant spruce is not attributable to the niche differentiation and site partitioning mechanism. An alternative hypothesis based on shifts in stand densities, species composition and climatic factors is more probable. [ABSTRACT FROM AUTHOR]

On Norway spruce (Picea abies L. [H.] Karst.) seedlings, influence of three treatments – (i) inoculation with Ectovit® preparation containing ectomycorrhizal fungi (INOCULATION), (ii) Ectovit® + Conavit® fertilizer (INOCULATION + FERTILIZATION), and (iii) untreated group (CONTROL) – were evaluated in this study. In autumn 2021 (3.5 years after inoculation), 100 seedlings/treatment (300 seedlings in total) were sampled to evaluate seedlings survival percentage and growth characteristics, and 10 live seedlings/treatment (30 seedlings in total) to evaluate dry weight and the number of seedlings with Armillaria rhizomorphs. By relating these values to the previous evaluation (autumn 2019), values for period autumn 2019 – autumn 2021 were obtained for statistical analyses. Increment of the seedling height, increment of the root collar diameter and increment of the seedling aboveground dry weight were significantly higher in INOCULATION compared to INOCULATION + FERTILIZATION, the first and second named variables were also significantly higher in INOCULATION compared to CONTROL. There were no significant differences in seedlings survival percentage nor number of seedlings with Armillaria rhizomorphs (all identified as Armillaria ostoyae [Romagn.] Herink). Contrary to the previous evaluation (1.5 years after inoculation), the protective effect of artificial ectomycorrhizal inoculation against infection of seedling by honey fungus was not confirmed. [ABSTRACT FROM AUTHOR]

This study aimed to compare patterns in the genetic structure of 27 mature stands and the natural regeneration of A. alba in the Eastern and Western Carpathians within the introgression zone of two refugial lineages from the Apennine and Balkan peninsulas. The distribution of the genetic diversity of fir stands was analysed using paternally inherited chloroplast DNA and five nuclear dominant inter simple sequence repeat markers (ISSRs). The study showed that the Balkan haplotype prevailed in both parental and progeny populations, and this haplotype was found in many mature Eastern Carpathian stands. Relatively high levels of genetic diversity were found in the mature stands (effective number of alleles Ne = 1.517, Shannon index I = 0.436, expected heterozygosity He = 0.295) and progeny (Ne = 1.515, I = 0.436 and He = 0.294) of silver fir. The analysis of molecular variance (AMOVA) revealed slight differences among the mature fir stands from the Western and Eastern Carpathians, with a value of 1.1%. According to principal coordinates analysis (PCoA) and STRUCTURE analyses, the populations, including stands of mature and progeny trees, were genetically separated into two groups. Slight genetic differences between the mature and progeny populations in the Polish Carpathians indicate sound gene pool transmission, which is essential for creating new selection and breeding programmes. [ABSTRACT FROM AUTHOR]

As a result of the imbalances in the forestry market and the increased demand for wood products worldwide, the resource of branches resulting from the exploitation of a forest has attracted special attention from researchers, in order to use these secondary resources judiciously and obtain an added value superior to classic uses. In this context, the current research took into consideration the use of spruce branches to obtain panels with a transverse structure. The work methodology has focused on the process of obtaining panels with a transverse texture and on determining the physical–mechanical properties of the created panels. The results regarding the panel density (determined as a ratio between mass and volume of specimens) showed about 693 kg/m3, static bending resistance parallel to the face of 5.5 N/mm2, resistance of adhesion of 5.6 N/mm2, shear strength parallel to face of 4.1 N/mm2, and screw pull-out resistance perpendicular to the face of 31.3 N/mm2, highlighting that the properties were in accordance with the European standards and that the panels obtained were suitable for obtaining furniture products with a special aesthetic aspect. As a general conclusion of the research, it can be stated that spruce branches are a sustainable wood resource with great possibilities to add more value in the form of panels with a traverse texture. [ABSTRACT FROM AUTHOR]

In recent years, phytofunctionalized AgNPs have attracted great interest due to their remarkable biological activities. In the present study, AgNPs were synthesized using Abies alba and Pinus sylvestris bark extracts. The chemical profile of these bark extracts was analyzed by LC-HRMS/MS. As a first step, the synthesis parameters (pH, AgNO3 concentration, ratio of bark extract and AgNO3, temperature, and reaction time) were optimized. The synthesized AgNPs were characterized by ATR-FTIR spectroscopy, DLS, SEM, EDX, and TEM. Their antioxidant, cytotoxic, and antibacterial properties were evaluated by the DPPH, ABTS, MTT, and broth microdilution assays, respectively. Abies alba and Pinus sylvestris bark extract-derived AgNPs were well-dispersed, spherical, small (average particle size of 9.92 and 24.49 nm, respectively), stable (zeta potential values of −10.9 and −10.8 mV, respectively), and cytotoxic to A-375 human malignant melanoma cells (IC50 = 2.40 ± 0.21 and 6.02 ± 0.61 μg/mL, respectively). The phytosynthesized AgNPs also showed antioxidant and antibacterial effects. [ABSTRACT FROM AUTHOR]

This study investigates the distribution of vegetation and its modern pollen representation along an elevation gradient in the Italian Alps and explores the relationships with terrain and climate variables. Moss polsters were collected at 25 sites between ca. 300 and 1400 m asl from open areas, deciduous, and conifer forests. At each site vegetation was surveyed at 1.8 and 10 m radius according to the Braun-Blanquet method. Climatic data, bioclimatic indices, and terrain parameters were obtained for each sampling site. Three distinct pollen associations reflect the characteristic vegetation altitudinal belts present in the study area. Uphill dispersal, the regional load and the presence of high producers influence the abundance of pollen and the representation of taxa along the gradient. CCA ordination technique reveals the predictive power of environmental variables on modern pollen and vegetation datasets. The most relevant factors controlling vegetation distribution are identified in elevation, insolation, Pspring, Tsummer, the Ellenberg quotient, and Summer Water Balance (SWB). Elevation, insolation, summer P and T, the Ellenberg quotient, and the Gams' hygric continentality index (GAMS) explain more variance within the pollen dataset. A qualitative comparison among pollen and the corresponding parent plant occurrence qualifies Abies alba, Fagus sylvatica, Poaceae and Cyclamen pollen as suitable indicators taxa of the local vegetation in the study area. Several high producers with very effective, long-distance anemophilous dispersal (Pinus, Ostrya, Alnus, and Juglans) or mixed pollination mechanisms (anemophilous and insect-pollination: Fraxinus ornus, and Castanea) show no or little association with their parent plants. [ABSTRACT FROM AUTHOR]

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]

In the context of global decline in old‐growth forest, historical ecology is a valuable tool to derive insights into vegetation legacies and dynamics and develop new conservation and restoration strategies. In this cross‐disciplinary study, we integrate palynology (Lago del Pesce record), history, dendrochronology, and historical and contemporary land cover maps to assess drivers of vegetation change over the last millennium in a Mediterranean mountain forest (Pollino National Park, southern Italy) and discuss implications in conservation ecology. The study site hosts a remnant beech–fir (Fagus sylvatica–Abies alba) mixed forest, a priority habitat for biodiversity conservation in Europe. In the 10th century, the pollen record showed an open environment that was quickly colonized by silver fir when sociopolitical instabilities reduced anthropogenic pressures in mountain forests. The highest forest cover and biomass was reached between the 14th and the 17th centuries following land abandonment due to recurring plague pandemics. This rewilding process is also reflected in the recruitment history of Bosnian pine (Pinus heldreichii) in the subalpine elevation belt. Our results show that human impacts have been one of the main drivers of silver fir population contraction in the last centuries in the Mediterranean, and that the removal of direct human pressure led to ecosystem renovation. Since 1910, the Rubbio State Forest has locally protected and restored the mixed beech–fir forest. The institutions in 1972 for the Rubbio Natural Reserve and in 1993 for Pollino National Park have guaranteed the survival of the silver fir population, demonstrating the effectiveness of targeted conservation and restoration policies despite a warming climate. Monitoring silver fir populations can measure the effectiveness of conservation measures. In the last decades, the abandonment of rural environments (rewilding) along the mountains of southern Italy has reduced the pressure on ecosystems, thus boosting forest expansion. However, after four decades of natural regeneration and increasing biomass, pollen influx and forest composition are still far from the natural attributes of the medieval forest ecosystem. We conclude that long‐term forest planning encouraging limited direct human disturbance will lead toward rewilding and renovation of carbon‐rich and highly biodiverse Mediterranean old‐growth forests, which will be more resistant and resilient to future climate change. [ABSTRACT FROM AUTHOR]

Scattered information about cordwood masonry was gathered from different sources such as books, professional articles, popular articles and websites. historical cordwood masonry construction techniques and newer cordwood masonry construction techniques were included. current teachings of ecological construction practices were added, and private and professional individuals' knowledge. three main cordwood wall types were evaluated and the wall type - single log with centered insulation space - was found to be optimal. spruce (Picea abies) was identified as the best suited tree species in norway. mixing of clay based mortar was explained. load bearing can be done with post framework, or the cordwood walls themselves can be load bearing. solutions for stabilising corners were found. it is optional to clad the house or leave it unclad. momentums for future scientific research were pointed out, such as finding thermal transmittance u (w/m2K) for woods and mortars, and understanding humidity transportation efficiency in different types of wood with/without cladding. unanswered questions were set forth. this is a pre-scientific literature study. [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]

Provenance trials replicated in multiple environments allow the selection of populations with high and stable performances. In this study, two methods have been applied to select stable Norway spruce provenances with high performances in three provenance trials established in Romania in 1972, where 81 provenances have been tested. Four traits were assessed: total and pruned height, diameter at breast height and survival rate. Two multi-trait indices have been used: multi-trait genotype-ideotype distance index (MGIDI) for each provenance trial and multi-trait stability index (MTSI) across provenance trials. The selection differential was between 0.2 and 17.8% better than each site means. Several Norway spruce provenances showed stability and high performances, as confirmed by both selection indices. Our results provide valuable information for the genetic improvement program and seed transfer guidelines based on assisted migration in this ecologically and economically important forest tree species. [ABSTRACT FROM AUTHOR]

Abstract Selective browsing by deer on young trees may impede the management goal of increasing forest resilience against climate change and other disturbances. Deer population density is often considered the main driver of browsing impacts on young trees, however, a range of other variables such as food availability also affect this relationship. In this study, we use browsing survey data from 135 research plots to explore patterns of roe deer (Capreolus capreolus) browsing pressure on woody plants in mountainous forests in central Europe. We fitted species‐specific generalised linear mixed models for eight woody taxa, assessing the potential effects of understory characteristics, roe deer abundance and lying deadwood on browsing intensity. Our study reveals conspecific and associational effects for woody taxa that are intermediately browsed by roe deer. Selective browsing pressure was mediated by preferences of plants, in that, browsing of strongly preferred woody taxa as for example mountain ash (Sorbus aucuparia) and of least preferred woody taxa, for example Norway spruce (Picea abies) was not affected by the surrounding understory vegetation, while browsing pressure on intermediately browsed species like for example silver fir (Abies alba) was affected by understory characteristics. Contrary to our expectations, roe deer abundance was only positively associated with browsing pressure on silver fir and bilberry (Vaccinium myrtillus), while all other plants were unaffected by deer abundance. Finally, we did not find an influence of lying deadwood volume on the browsing pressure on any woody‐plant species. Overall, our results indicate that patterns in browsing preference and intensity are species‐specific processes and are partly affected by the surrounding understory vegetation. Current management strategies that aim to reduce browsing pressure through culling may be inefficient as they do not address other drivers of browsing pressure. However, managers also need to consider the characteristics of the local understory vegetation in addition to deer abundance and design species‐specific plans to reduce browsing on woody plant taxa.

In the last 50 years, forest disturbances, caused mainly by insect outbreaks and windstorms, had a significant impact on the subalpine Norway spruce (Picea abies (L.) H. Karst.) stands across Europe. The high intensity of these factors often led to complete dieback of existing forest stands, as in Gorce National Park (Southern Poland). The aim of this study was to monitor land cover changes in subalpine Norway spruce stands and their dynamics in Gorce NP in the years 1977–2020 (43 years), with the use of archival remote sensing data. The study area was divided into two subareas: A—the Kudłoń and B—the Jaworzyna range. Changes were tracked in six defined land cover classes, based on available aerial orthophotos and Landsat (NASA) imagery, with the help of the authors' photointerpretation key. The results showed that almost 50% of old-growth Norway spruce stands died in the analyzed time period (50.9% in subarea A; 48.8% in subarea B). However, young forests appeared in almost 17% of the study area (20.7% and 14.2% in subarea A and B, respectively). The dynamics of land cover changes were different for the analyzed subareas; in subarea A Norway spruce dieback processes weakened at the end of the analyzed time period, whereas in subarea B they maintained high intensity. The process of old-growth Norway spruce stands dieback is still occurring in Gorce NP, but it does not result in the disappearance of the whole subalpine spruce forest ecosystem but is rather a generational change, due to emerging young forests. [ABSTRACT FROM AUTHOR]

Biogenic volatile organic compound (BVOC) emissions from trees subjected to biotic stress are higher compared to healthy trees, and they may also have a different compound composition. This in turn affects atmospheric chemistry and can lead to either positive or negative feedback to the climate. Climate change favors the abundance of the European spruce bark beetle (Ips typographus) which attacks the bark of Norway spruce (Picea abies) trees, causing induced BVOC emissions from the trees as a response to the insect stress. Here, results are reported from a study analyzing the difference in emission rates between healthy and bark-beetle-infested Norway spruce trees, changes in emission rates over time since the infestation started, and differences in emission rates from bark-beetle-drilled entry and exit holes. Bark chamber measurements on both healthy and infested trees were performed during the summer of 2019 at Hyltemossa and Norunda research stations in Sweden. The measurements showed that induced BVOC emissions following the bark beetle infestation were dominated by entry hole emissions in the early growing season and exit hole emissions in the later season. The results showed a significant difference in emission rates between healthy and infested trees during both seasons. The seasonal average standardized BVOC emission rate of healthy trees was 32 ± 52 µ g m -2 h -1 (mean ± standard deviation), while the average standardized BVOC emission rates of infested trees were 6700 ± 6900 and 2000 ± 1300 µ g m -2 h -1 during the early and late season respectively. BVOC emission rates were highest at the start of the infestation and decreased exponentially with time, showing induced emission rates for up to 1 year after which the emission rates were similar to those from healthy bark. Constitutive needle emission rates from healthy trees were found to be 11 times higher than bark emissions from healthy trees. However, when Norway spruce trees were infested, the bark emission rates were instead 6 to 20 times higher than the needle emissions, causing substantial increases in the total tree BVOC emission rate. This could lead to high impacts on atmospheric processes, specifically the formation of secondary organic aerosols, which have a higher yield from some monoterpene compounds, which increased from infested trees. [ABSTRACT FROM AUTHOR]

Key message: The TreeTrace_spruce database contains images and measurements of 100 Norway spruce (Picea abies (L.) H.Karst.) logs from Northeastern France, each about 4.5 m long. The image database includes RGB images of large and small ends of the logs and hyperspectral and computed tomography (CT) images of wood discs sampled at both log ends. The 100 logs were also fully X-ray scanned with a CT device for roundwoods and their top surface was scanned with a terrestrial LiDAR device. The measurements performed on discs include wood local density, growth ring widths and pith location. This database is complementary to another one (TreeTrace_Douglas) resulting from the same ANR project TreeTrace, but if the objectives are similar, the protocols and conditions of acquisition are not the same for these two databases. TreeTrace_spruce dataset is available at https://doi.org/10.57745/WKLTJI and associated metadata are available at https://metadata-afs.nancy.inra.fr/geonetwork/srv/fre/catalog.search#/metadata/cffee2f1-18e1-4b53-9f5b-6cc4c66f1cb8. [ABSTRACT FROM AUTHOR]

Hybridization is a process of great importance in the ecology and evolution of plants. However, identifying hybrids is not an easy task, especially in cases of sympatry. Such cases are the Abies taxa in Greece; Silver fir (A. alba), Greek fir (A. cephalonica) and King Boris fir (A. × borisii-regis). The latter has been characterized as a hybrid between the first two species as its morphological traits are either a combination of the parental ones or intermediate. Besides the morphological traits, A. × borisii-regis has so far been identified only at the population level, with biochemical and DNA markers. Here, we describe the identification of A. × borisii-regis at the individual level by employing a species-specific marker in the cpDNA and another in mtDNA, taking advantage of their uniparental inheritance mode from the paternal and the maternal parent, respectively. In addition, based on these markers, essential information emerges on the distribution and the mtDNA diversity of the Abies taxa in Greece. [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]

The present study analysed how growth of the Norway spruce (Picea abies (L.) H.Karst.) is influenced by site conditions throughout the Eastern and Southern Romanian Carpathians. In order to achieve the aim and the objectives stated in the present study, the volume of spruce stands was taken into account and grouped into six transects, both in the north–south direction in the Southern Carpathians and in the east–west direction in the Eastern Carpathians. We used data that were extracted from the forest management plans of the areas, carried out during the period of 1980–2005. For the Eastern Carpathians, the results revealed that at the same altitudes (700–1000 m), the volumes were higher on the eastern cline than on the western. In the case of the Southern Carpathians, for altitudes between 1300 and 1600 m, the volume of trees in the southern cline was greater than that of the trees in the northern cline. It was also found that the pure spruce stands had higher growth than the mixed ones for the same age and altitude; this was true in the cases of both the Eastern and Southern Carpathians. [ABSTRACT FROM AUTHOR]

Context: A significant forest decline has been noticed these last years in Europe. Managers need tools to better anticipate these massive events. Objectives: We evaluated the efficiency of easily available data about environmental conditions and stand characteristics to determine different levels of vulnerability. Methods: We combined remote sensing images, photo-interpretation, and digital models describing environmental conditions within a modelling approach to achieve spatial vulnerability assessment of the stands. We focused on silver fir and Norway spruce stands in the Vosges mountains (8900 km2, northeastern France), where severe symptoms of decline are visible. Results: Silver fir were predicted highly vulnerable on 7% of their area versus 33% for Norway spruce. Using an independent dataset, we observed ten-times (silver fir) and two-times (Norway spruce) higher mortality rates in the units with a high level of vulnerability than in the others. About half of the model deviance was directly or indirectly explained by variables related to water stress (soils displaying low water availability, having suffered severe drying events these last years). Furthermore, the stands acclimatised to drought conditions were more resilient. Stand characteristics also influenced dieback spread, suggesting that an evolution of silvicultural practices toward mixed stands with broadleaved species and uneven-aged trees can contribute to better adapt to future climate conditions. Conclusion: Vulnerability maps based on easily available geographic information describing climate, soil, and topography can efficiently discriminate canopy mortality patterns over broad areas, and can be useful tools for managers to mitigate the effects of climate change on forests. [ABSTRACT FROM AUTHOR]

Although many studies have evaluated plant ecophysiological responses to increasing atmospheric carbon dioxide concentration (CO2) and increasing temperature, few studies have addressed the interactive effects of these two factors, especially on high-altitude trees that are more sensitive. To address this issue, we used Abies faxoniana and Picea purpurea seedlings to evaluate the effects of elevated CO2 (CeTa, 700 ppm), elevated temperature (CaTe, 2 °C above ambient temperature) and elevated CO2 combined with elevated temperature (CeTe) on plant growth, morphology and physiological responses. We found that CaTe increased conifer total dry mass, specific root length, net photosynthesis rate and translocation rates of 15NH4+ and 15NO3−, but CeTe had stronger responses (except net photosynthesis rate of A. faxoniana). These results indicate that the effect of elevated temperature on the growth and physiological responses is enhanced by elevated CO2. Furthermore, effect of CeTe on physiological traits was higher in P. purpurea , which possessed a higher total dry mass, specific leaf area, water use efficiency (δ 13C), δ 15NO3−-N level, translocation rates of 15NH4+ and 15NO3− and total nonstructural carbohydrates than A. faxoniana. Overall, these findings suggest that the interactive effects of CO2 × temperature should be considered when assessing conifer responses to future climates. [ABSTRACT FROM AUTHOR]

Litterfall of silver fir contributes to development of forest floor similarly like Norway spruce litterfall does. The nutrient return to soil can be intensified by mixing these conifers with other tree species whose effects on soil are positive; our study deals with European rowan. The study aimed at firs and rowans in alternating rows (Fi-Ro) compared to the monospecific plantation of fir (Fi) at two former meadow sites with the stands of 20 and 17 years of age, respectively. Both organic forest floor and its mineral subsurface were sampled. Rowan admixed to the silver fir plantation improved both the uppermost layer and the topsoil as higher pH, more favourable soil-sorption properties and higher plant available magnesium were found below Fi-Ro compared to Fi. Fine dry matter was higher below Fi, which was reflected in higher organic carbon (Cox), combustible matter and nitrogen pools. Besides the effects of trees on the soil, silvicultural issues such as renewal costs and tree species performance in monospecific and mixed stands were presented and discussed. [ABSTRACT FROM AUTHOR]

Silver fir (Abies alba Mill.) is still counted among drought-tolerant tree species. However, its ability to cope with the recent extremely dry period has not yet been sufficiently studied. The objective of research was to analyse di- fferences in the climate-growth response between silver fir, Norway spruce (Picea abies L. Karst.) and European larch (Larix decidua Mill.) growing in areas with large-scale disintegration of spruce stands. In 2019-2021, the increment cores were sampled at 16 sites along the altitudinal gradient of 340-775 m a.s.l. in different regions of the Czech Republic affected by bark beetle outbreak. The radial growth pattern of fir was compared with that of spruce or larch growing under the same site conditions. In fir, the missing rings were frequently recorded during the period of peak SO2 pollution load in 1966-1985, but they were rarely identified in recent years. In spruce and larch, missing rings were less common and occurred mainly in the recent dry period after 2015. Fir was less sensitive to summer drought compared to larch and especially to spruce, which showed high sensitivity to summer drought regardless of the altitude. The significant positive response of fir to summer precipitation was recorded at sites up to 450 m a.s.l., however, its sensitivity to drought has increased in the last two decades. Hence, when considering the wider use of fir, it is necessary to respect its ecological requirements as much as possible in order to preserve its vitality and production potential in changing climatic conditions. [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]

Forests in central Europe were affected by heavy bark beetle outbreak during the years 2014-2022. Decline of Norway spruce brought other species of forest trees, including the fir, to the fore. The nutritional level of silver fir is one of the studied topics. Needles in 14 Norway spruce (NS) -- silver fir (SF) mixed forest stands from 4 regions in the Czech Republic have been sampled to survey their nutrition level. Nutrition of NS is often near or below the deficiency limit, while nutrition of SF was assessed as sufficient or good. Differences between both regions and tree species were found. SF drew more nutrients from the soil profile than NS on the same forest site. Differences between NS and SF in nutrient concentrations in needles were significant for N, Ca, Mg, Zn and S and non-significant for P and K. [ABSTRACT FROM AUTHOR]

Pine wilt disease (PWD) caused by the pine wood nematode (PWN) is China's most serious forest disease in recent decades. Its complex disease system with unclear pathogenesis and differentiated pathogenicity makes it challenging to manage and control. PWD has spread rapidly in Northeast and Northwest China in recent years, exceeding previous predictions and the traditional understanding of its potential distribution. This paper reviewed the comprehensive risk of PWD in Northeast and Northwest China through the occurrence of influencing factors. Regarding PWN's temperature resistance, all regions of China are suitable for PWD. In terms of altitude, the PWD system is mainly distributed below 1000 m. In China, Pinus and Larix species are confirmed host trees of PWN, while Monochamus alternatus and M. saltuarius are confirmed vector insects of PWN. In this case, PWD may occur in all low-altitude pine forests in China. Northeast China has a higher risk than Northwest China due to its distribution of suitable host trees and vector beetles at low altitudes. To confront the threat, two scientific bottlenecks are required to be demonstrated. The first is the pathogenicity of Chinese PWN strains to Chinese Picea and Abies species. The other is the geographical distribution and highest altitude distribution of other Monochamus species in the Palaearctic region of China and their PWN transmission ability. We also suggest strengthening plant quarantining in Northeast China. In conclusion, this review comprehensively analyzes the risk of PWD in Northeast and Northwest China in terms of temperature, altitude, host trees, and vector insects. It provides a new perspective and reference for the management and research of PWD in China. [ABSTRACT FROM AUTHOR]

Microgeographical adaptation occurs when the effects of directional selection persist despite gene flow. Traits and genetic loci under selection can then show adaptive divergence, against the backdrop of little differentiation at other traits or loci. How common such events are and how strong the selection is that underlies them remain open questions. Here, we discovered and analysed microgeographical patterns of genomic divergence in four European and Mediterranean conifers with widely differing life‐history traits and ecological requirements (Abies alba MIll., Cedrus atlantica [Endl.] Manetti, Pinus halepensis Mill. and Pinus pinaster Aiton) by screening pairs from geographically close forest stands sampled along steep ecological gradients. We inferred patterns of genomic divergence by applying a combination of divergence outlier detection methods, demographic modelling, Approximate Bayesian Computation inferences and genomic annotation to genomic data. Surprisingly for such small geographical scales, we showed that selection is strong in all species but generally affects different loci in each. A clear signature of selection was systematically detected on a fraction of the genome, of the order of 0.1%–1% of the loci depending on the species. The novel modelling method we designed for estimating selection coefficients showed that the microgeographical selection coefficient scaled by population size (Ns) was 2–30. Our results convincingly suggest that selection maintains within‐population diversity at microgeographical scales in spatially heterogeneous environments. Such genetic diversity is likely to be a major reservoir of adaptive potential, helping populations to adapt under fluctuating environmental conditions. [ABSTRACT FROM AUTHOR]

Summary: Ectomycorrhizal exploration types are commonly assumed to denote spatial foraging patterns and resource‐related niches of extraradical mycelia. However, empirical evidence of the consistency of foraging strategies within exploration types is lacking.Here, we analysed ectomycorrhizal foraging patterns by incubating root‐excluding ingrowth mesh bags filled with six different substrates in mature Picea abies forests. High‐throughput sequencing was used to characterise ectomycorrhizal fungal communities in the mesh bags and on adjacent fine roots after one growing season.Contrary to expectations, many ectomycorrhizal genera of exploration types that are thought to produce little extraradical mycelium colonised ingrowth bags extensively, whereas genera commonly associated with ample mycelial production occurred sparsely in ingrowth bags relative to their abundance on roots.Previous assumptions about soil foraging patterns of exploration types do not seem to hold. Instead, we propose that variation in the proliferation of extraradical mycelium is related to intergeneric differences in mycelial longevity and the mobility of targeted resources. [ABSTRACT FROM AUTHOR]

Radial tree growth is sensitive to environmental conditions, making observed growth increments an important indicator of climate change effects on forest growth. However, unprecedented climate variability could lead to non‐stationarity, that is, a decoupling of tree growth responses from climate over time, potentially inducing biases in climate reconstructions and forest growth projections. Little is known about whether and to what extent environmental conditions, species, and model type and resolution affect the occurrence and magnitude of non‐stationarity. To systematically assess potential drivers of non‐stationarity, we compiled tree‐ring width chronologies of two conifer species, Picea abies and Pinus sylvestris, distributed across cold, dry, and mixed climates. We analyzed 147 sites across the Europe including the distribution margins of these species as well as moderate sites. We calibrated four numerical models (linear vs. non‐linear, daily vs. monthly resolution) to simulate growth chronologies based on temperature and soil moisture data. Climate–growth models were tested in independent verification periods to quantify their non‐stationarity, which was assessed based on bootstrapped transfer function stability tests. The degree of non‐stationarity varied between species, site climatic conditions, and models. Chronologies of P. sylvestris showed stronger non‐stationarity compared with Picea abies stands with a high degree of stationarity. Sites with mixed climatic signals were most affected by non‐stationarity compared with sites sampled at cold and dry species distribution margins. Moreover, linear models with daily resolution exhibited greater non‐stationarity compared with monthly‐resolved non‐linear models. We conclude that non‐stationarity in climate–growth responses is a multifactorial phenomenon driven by the interaction of site climatic conditions, tree species, and methodological features of the modeling approach. Given the existence of multiple drivers and the frequent occurrence of non‐stationarity, we recommend that temporal non‐stationarity rather than stationarity should be considered as the baseline model of climate–growth response for temperate forests. [ABSTRACT FROM AUTHOR]

In the present study, we conduct a phytosociological analysis of the Pulmonario rubrae-Fagetum association, identified in the northern part of the Semenic Mountains in southwestern Romania. The aim of the research is to perform a floristic, phytocenological, ecological, ecoprotective and bioeconomic study of the beech forests in the Banat region, formed by Fagus sylvatica, Abies alba, Pulmonaria rubra and Symphytum cordatum, identified in the northern part of the Semenic Mountains. The phytocoenoses of these forests have been analyzed in terms of physiognomy, floristic composition, spectrum of life forms, floristic elements and the influence of ecological factors. The discussions summarize the main differences in biodiversity research between the Semenic Mountains and the results of research in the Orăștie River Basin (Șureanu Mountains). [ABSTRACT FROM AUTHOR]

The relationships between the rhizosphere factor Rf values for a number of indices of soil biological activity, allocation in soil horizons, and bacterial community structure in the rhizosphere and the bulk soil of Retisol under spruce trees (Picea abies L.) have been studied in the Central Forest Nature Reserve (Tver oblast, Russia). The Rf expressed as the ratios of soil characteristics in the rhizosphere to those in the bulk soil are determined for the basic indices of microbial respiration, biomass, and available nutrient pools in the humus-accumulative AEL (3–15 cm) and eluvial EL (15–46 cm) horizons. The most prominent rhizosphere effect (Rf > 1.6) is observed for microbial biomass, basal respiration, and the turnover rate of soil organic matter (SOM). The Rf value for the SOM turnover rate in AEL horizon is approximately 1.5, reaching as high as 6 in the EL horizon. The rhizosphere demonstrated a higher microbial diversity with a significant contribution of both gram-positive and gram-negative bacteria, including representatives of Acidobacteria, Alphaproteobacteria, Betaproteobacteria, Gammaproteobacteria, Solibacteres, and Spartobacteria. The gram-positive orders Bacillales and Clostridiales are prevalent in the bulk soil, with the relative contributions of over 80 and 50% for the AEL and EL horizons, respectively. The number of microbial activity indices with high Rf values (three for the EL horizon and only one for the AEL horizon) suggests that the rhizosphere of the lower horizon is a more pronounced "hotspot" of biological activity than that of the topsoil. [ABSTRACT FROM AUTHOR]

Summary: The quantification of the intensities of tree growth responses to the impact of geomorphic processes is a modern research trend in dendrogeomorphology. It enables a more sensitive assessment of the activity of the studied geomorphic process compared to the traditional use of growth disturbances. The advanced definitions of individual intensity classes of growth disturbances are based exclusively on macroscopic observations. This study evaluates the possibility of anatomical quantification of compression wood (CW) intensity in the case of common spruce (Picea abies (L.) Karst.) and compares it with subjective macroscopic evidence of CW with respect to stem tilting intensity. In total, 25 disturbed (tilted) individuals of P. abies occupying a landslide active during July 1997 were sampled, and 21 of them were analysed. The intensity of external disturbance (stem tilting) was compared against the macroscopic (intensity and duration) and microscopic (quantitative change of the tracheid lumen area and the cell wall proportion) parameters of compression wood suitable for practical application in common dendrogeomorphic analysis. Generally, the macroscopic indices of CW were strongly correlated with stem tilting. The intensity of the anatomical growth response was stronger in the earlywood zone than in the latewood zone. Nevertheless, their dependence on stem tilting was not detected. Results suggest that CW classification based on the quantification of anatomical changes is not possible for dendrogeomorphic purposes. Nevertheless, based on the obtained results, the present study suggests preferring the most intensively tilted trees during future dendrogeomorphic research to obtain the most intensive macroscopic and subjective observable anatomical evidence for studying compression wood. [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]

Stumps and knotwood of Norway spruce (Picea abies) are valuable sources of wood extractives. Although lignans from knotwood have already been utilized in value-added products, the behavior and valorization of stump-derived extractives are less studied. In this study, the composition of lipophilic and hydrophilic extractives, particularly lignans, from various spruce stump samples (stump bottom, stump heart, and crushed stump samples) stored outside were studied. Lipophilic and hydrophilic extracts were separated with an accelerated solvent extraction (ASE) apparatus using n-hexane and hot water, respectively. The detailed extractives content of samples was then determined by gas chromatography equipped with a flame ionization detector and a mass detector (GC-FID/MS) and high-performance liquid chromatography (HPLC). In stump bottom samples, an apparent decrease in total dissolved solids was observed in all the major extractives groups during storage: lignans, sugars, stilbene–glucosides, organic acids, resin acids, fatty acids, diterpenoids, and sterols. While a definitive decrease in extractives could not be demonstrated due to the moderately high variation of extractives among different samples, a good indication of the accessibility of important extractives in weathered stumps was obtained. Of the identified hydrophilic extractives, 79% were lignans, 53% of them being composed of 7-hydroxymatairesinol (HMR), 16% conidendric acid, and 12% todolactol. After 12 weeks of storage, the total amount of lignans was 15.3 mg/g of dry matter in stump bottom, 17.0 mg/g of dry matter in stump heart samples, and 10.2 mg/g of dry matter in crushed stump samples. [ABSTRACT FROM AUTHOR]

Climate change can affect forest ecosystems, especially through an increase of extreme events. In order to verify whether mycosilvicultural practices could mitigate the effects of climate change, productivity of Boletus edulis in Abies alba managed plantations was correlated to intense rainfall and temperature peaks during three years. Fungal productivity in each of the 21 days following an extreme climatic event was considered. Results showed that sudden increases in maximum temperature seemed to have an inhibitory effect on B. edulis productivity in sites with no or modest thinning. In sites with heavy thinning, productivity seemed to be favoured by high temperatures, starting from the twentieth day following the extreme event. Mycosilviculture may mitigate the climate change effects; however, further studies are needed to verify how climate-dominated effects can be altered by local factors and how ecological relationship between B. edulis and forest ecosystem will be affected. [ABSTRACT FROM AUTHOR]

Considering the changing climatic conditions, the Czech and Slovakian vegetation has been vertically divided into Forest Vegetation Zones (FVZs) units. Each FVZ is represented by a specific tree species, i.e., the oaks (Quercus sp.), European beech (Fagus sylvatica L.), silver fir (Abies alba Mill.), Norway spruce (Picea abies (L.) H. Karst.) and dwarf pine (Pinus mugo Turra). The FVZ concept has been applied in the Czechoslovakian forestry classification practice since the 1950s. Due to the broad time span of the studied topic, this article is divided into five chapters regarding the evolution of the FVZ concept. Its currently applied form was established primarily in the 1970s on the grounds of data gathered during two decades of forest typology research. An FVZ unit has become an upper unit of the Czech Forest Ecosystem Classification since its legislative codification in the Forest Act (289/1995) in 1995. To this day, however, the FVZ concept has not been reassessed by advanced, multi-dimensional statistical methods. This paper aims to describe key moments of the development of this concept and provide a perspective on its limitations, also in connection with current trends in ecological research. This review aims to provide a better understanding of the forest vegetation-environment relationship in the Czech Republic in relation to climate change, indirect anthropogenic environmental impact, and prediction of forest and landscape ecosystems response [ABSTRACT FROM AUTHOR]

Norway spruce (Picea abies) is one of the most important commercial conifer species naturally distributed in Europe. In this paper, the composition and abundance of essential oil and hydrosol from the needles and branches of P. abies were investigated with an additional evaluation of changes related to different times of the year, annual shoots and branches, and differences in composition under different microenvironments. Essential oils and hydrosols obtained via hydrodistillation were analyzed using gas chromatography–mass spectrometry (GC-MS), where 246 compounds in essential oil and 53 in hydrosols were identified. The relative amounts of monoterpenes, sesquiterpenes, and diterpenes in essential oil changed significantly during the year, with the highest peak of monoterpenes observed in April (72%), the highest abundance of sesquiterpenes observed in August (21%), and the highest abundance of diterpenes observed in June (27%). The individual compound with the highest variation was manool, with variation from 1.5% (April) to 18.7% (June). Our results also indicate that the essential oil with the lowest allergenic potential (lowest quantity of limonene and linalool) was obtained in late spring or summer. Location had no significant influence on composition, while the method of collection for distillation (whole branch or annual shoots) had a minor influence on the composition. All nine main compounds identified in the hydrosol samples were oxygenated monoterpenes. The composition of P. abies hydrosol was also significantly affected by season. The method of preparing the branches for distillation did not affect the composition of P. abies hydrosol, while the location had a minor effect on composition. [ABSTRACT FROM AUTHOR]

Featured Application: A better understanding of mold growth on wood and the parameters on which this growth depends will lead to improved calculation models for predicting mold occurrence in buildings and building components. The possible influence of anatomical sections of wood on mold growth was investigated by means of a laboratory experiment. The selected fungi, Aspergillus sp., Penicillium sp., and Alternaria sp. were inoculated by spraying on the surface of wood specimens prepared from pine (Pinus sylvestris) and spruce (Picea abies). The incubation was carried out under stable environmental conditions (temperature of 22 °C, relative humidity of 75, 87, and 95%) over three months. Mold growth was evaluated based on regular microscopic and macroscopic observations. The recorded mold coverage fractions and the qualitative indicators of mold development were later expressed by a dimensionless mold index. The differences in mold growth in the anatomical sections of wood were found to be relatively insignificant. In contrast, comparison of measured data with other experimental studies showed large differences, especially in the initial growth phase. The discrepancy is probably related to differences among the experimental protocols. It is concluded that laboratory mold growth studies would be improved if a common standardized methodology was developed and followed. [ABSTRACT FROM AUTHOR]

Silver fir is one of the most important tree species not only in Bosnia and Herzegovina, but also in whole of Europe. For natural regeneration of fir, the most important factors are site condition, share of fir in the stand and tree species composition. The aim of this study was to determine if there are statistically important differences in the number of seedlings and height increment at different competition situations between adult trees. Study area was located at Bjelašnica mountain. Data were collected on circular plots with a radius of 12.62m for trees with dbh above 5 cm, and radius 3 m for regeneration layer. The competition is expressed using Hegyi competition index, where for the calculation a dominant tree from each quadrant was used. We analysed the total number of fir individuals in regeneration layer and height increment for categories 50-130 cm height and 0.1-5 cm dbh. The results showed that there are no statistically significant differences in the number of for seedlings at different values of the Hegye index. Statistically significant differences were found in terms of height increment. Height increment decreased with increasing competition between trees. [ABSTRACT FROM AUTHOR]

Green Douglas-fir was introduced in the Călimănești Forest District at the beginning of the 20th century. Currently, there are 78 stands with green Douglas-fir covering 1451.1 ha, of which the species itself is found on 389.15 ha. Only seven of these stands are pure (share of green Douglas-fir at least 80 per cent), whereas the majority of them (71) are mixed with both softwoods (e.g., Norway spruce, silver fir, Scots pine and European larch) and broadleaves (predominantly European beech, sessile oak, hornbeam, and sycamore maple, but also wild cherry, small-leaved linden, and common ash). The species was used especially in the European beech vegetation layer, at altitudes ranging from 250 m to 1100 m. Consequently, the soils under these stands are extremely variable, from brown to brown podzolic or even podzols. Green Douglas-fir has shown remarkable high resistance to disease and pathogens, as well as no damaging effects of snow or wind. Throughout the area, diameters and heights of the species are higher than those of cohabitants, either softwoods or broadleaves. In the oldest stand (115 years old) green Douglas-fir has reached 83.2 cm in diameter and 40.5 m in height, with a wood production of 1167.1 m³ ·ha-1. [ABSTRACT FROM AUTHOR]

The aim of this research was to quantify the content of hazardous elements in the needles of Norway spruce (Picea abies L.) in the natural habitats that were accumulated from thermal power plants, mines, and metal processing industry. Fifteen natural populations of the Norway spruce were sampled from the mountain ranges in Southeastern Europe (Dinaric Alps and Balkan Mountains). Two-year-old spruce needles were evaluated the content of the following hazardous elements: heavy metals cadmium, mercury, nickel, lead and zinc, and metalloid arsenic. The effect of the distance between air pollution emitters and the Norway spruce natural habitats on the hazardous elements content in needles was also evaluated. The results of the analysis of variance confirmed interpopulation differences in the content of all analyzed hazardous elements. The effect of the air pollution source (thermal power plants, mines, and industry) on the content of hazardous elements in the spruce needles was also assessed. Significant correlation was found between the distance of air pollution emitters and the amount of zinc. This study could serve as the startup point of future monitoring programs and provide new prospect of using Norway spruce needles as the bioindicator of air pollution with hazardous elements on Balkan Peninsula since the fact that the Norway spruce natural populations inhabit wide geographic range of the continental Europe, from the Balkan Peninsula, over European Alps to Scandinavia and a large-scale of altitude from 980 to 1860 m above sea level. [ABSTRACT FROM AUTHOR]

Natural forests have unique, very stable structures and host a large number of endemic species, making them of high conservation value. The Șinca Old-Growth Forest in Brasov County (Romania) is no exception, being a flagship natural forest of mixed beech and silver fir among European mountain forests. Knowledge of the diversity of beetles living in this ecosystem and of the conservation degree of the species can be obtained by comparing it with the diversity existing in a managed forest, similar in composition and structure. Thus, the present study allowed a first analysis of the terrestrial coleopteran communities captured in pitfall traps both in a forest reserve and in a managed forest. The abundance of captured beetles was about 17% higher in the forest reserve (16,393 individuals) than in the managed forest (14,008 individuals), while species richness was higher in the managed forest (44 species), where 19.1% more taxa were identified than in the forest reserve (37 species). There were significant differences between the two beetle communities indicated via a PERMANOVA test; these differences are most likely due to the presence of certain beetle species only in a certain stand type, but also due to large differences between populations of common insect species. Analyses of the Shannon, Simpson, Evenness, and Berger–Parker diversity indices showed a similar diversity between the two terrestrial beetle communities. The presence of rare species such as Carabus variolosus (Fabricius, 1787), Ceruchus chrysomelinus (Hochenwarth, 1785), and Rhysodes sulcatus (Fabricius, 1787) indicates the high value of this ecosystem and illustrates the importance of its conservation. A more in-depth analysis of beetle diversity in the Șinca forest may only be possible after further research based on additional beetle sampling methods capable of capturing dead wood-dependent insects in particular. [ABSTRACT FROM AUTHOR]

The current study is the first to describe fertility dynamics in a Silver fir (Abies alba Mill.) seed orchard and among the few reporting related information from a mature seed orchard. The research aim was to evaluate the female cone production in order to provide support to future management measures. Observations were conducted in a clonal seed orchard from the Eastern Carpathians over six years; all the ramets of 44 clones and the zero-inflated data were analyzed with generalized lineal mixed effects models in a Bayesian framework. The results indicated a higher influence of the year and probably of the sensitivity to climate, and less variability between clones, in both the Poisson and zero-inflated components of cones production. The repeatability of mean annual clone production suggests moderate continuity of cone crops in the production rank of individual clones, while the estimates of heritability were under a moderate genetic control. The values of heritability were influenced by the reporting scale (latent vs. original data scale); therefore, caution in the analysis of non-Gaussian data and in comparisons of heritability between seed orchards is required. The variation of the female cone production was higher than expected for a seed orchard, but with marked variation across years, similar to other related indicators, patterns specific to mature, and productive commercial seed orchards. Several management options to be applied in the future were also discussed. [ABSTRACT FROM AUTHOR]

Silver fir (Abies alba Mill.) is a flexible European tree species, mainly vegetating within the mountainous regions of Europe, but its growth responses across its latitudinal and longitudinal range have not yet been satisfactorily verified under changing environmental conditions. This study describes the tree-ring increment of silver fir in research plots across a latitudinal gradient from the northern range in Czechia (CZ), through Croatia (HR) to the southernmost range in Italy (IT). The research aims to analyze in detail the dynamics and cyclicity of the ringwidth index (RWI) and how it relates to climatic factors (temperature and precipitation), the North Atlantic Oscillation (NAO), and total solar irradiance (TSI), including the determination of latitude. The results show that the main drivers affecting fir growth are the seasonal NAO index and TSI. Monthly temperatures affect RWI early in the vegetation season, while lack of precipitation during the summer is a limiting factor for fir growth, especially in July. Seasonal temperatures and temperatures in June and July negatively impact, while seasonal precipitation totals in the same months positively influence the RWI in all research plots across meridian. The longest growth cycles in fir RWI were recorded in the northernmost studied plots in CZ. These cyclical fluctuations recede approaching the south. The cyclic increase in RWI is related to the TSI, which decreases its effect from north to south. The TSI's effects vary, positively impacting CZ but negatively influencing HR while remaining relatively neutral in IT. On the other hand, seasonal NAO tends to negatively affect silver fir growth in HR and CZ but has a mildly positive effect in IT. In conclusion, the TSI and the influence of the seasonal NAO index are prevalent in the fir RWI and are accompanied by a greater cyclicity of RWI in Central Europe (temperature optimum) than in the Italian Mediterranean region, where this tree species is limited by climatic conditions, especially lack of precipitation. [ABSTRACT FROM AUTHOR]

The genetic system represents the genetic pathway of organisms for organizing and transmitting genetic material that determines the balance between coherence, gene recombination, and control over the amount and type of gene combinations. The objective of this paper is to present the main characteristics of the genetic system of several species of forest trees, namely: Picea abies, Abies alba, Larix decidua, Pinus sylvestris and Quercus robur. The main characteristics of the genetic system taken into account refer to: the mode of reproduction; population dynamics type; chromosomal cycle; recombination index; presence or absence of chromosomal genetic polymorphism, etc. The used methods included searching of the various databases with the latest publications in the field and identification of some relevant results. In the case of forest trees, the genetic systems present a special situation, compared to other higher plants; is about a particular configuration of the systems components. An optimal genetic system of long-lived species, such as forest trees, is characterized by a high recombination index and cross-pollination; however it is possible to change the rate of genetic recombination through selection. [ABSTRACT FROM AUTHOR]

Centuries of intensive land and forest use (fire, grazing, and coppicing) have reduced silver fir populations and promoted pure beech stands in most of the Apennines. Silver fir is a vulnerable forest species that creates mixed forests with beech in the Mediterranean mountains. Young silver fir trees do not produce pollen and their recent recolonization of seminatural beech forests still eludes palaeoecological reconstructions. [Extracted from the article]

Climate change is expected to increase the frequency and intensity of summer droughts. Sufficient drought resistance, the ability to acclimate to and/or recover after drought, is thus crucial for forest tree species. However, studies on the hydraulics of mature trees during and after drought in natura are scarce.In this study, we analysed trunk water content (electrical resistivity: ER) and further hydraulic (water potential, sap flow density, specific hydraulic conductivity, vulnerability to embolism) as well as wood anatomical traits (tree ring width, conduit diameter, conduit wall reinforcement) of drought‐stressed (artificially induced summer drought via throughfall‐exclusion) and unstressed Picea abies and Fagus sylvatica trees.In P. abies, ER indicated a strong reduction in trunk water content after 5 years of summer drought, corresponding to significantly lower pre‐dawn leaf water potential and xylem sap flow density. Vulnerability to embolism tended to be higher in drought‐stressed trees. In F. sylvatica, only small differences between drought‐stressed and control trees were observed.Re‐watering led to a rapid increase in water potentials and xylem sap flow of both drought‐stressed trees, and to increased growth rates in the next growing season. ER analyses revealed lower trunk water content in P. abies trees growing on throughfall‐exclusion plots even 1 year after re‐watering, indicating a limited capacity to restore internal water reserves. Results demonstrated that P. abies is more susceptible to recurrent summer drought than F. sylvatica, and can exhibit long‐lasting and pronounced legacy effects in trunk water reserves. [ABSTRACT FROM AUTHOR]

Climate change‐related environmental stress has been recognized as a driving force in accelerating forest mortality over the last decades in Central Europe. Here, we aim to elucidate the thermal sensitivity of three native conifer species, namely Norway spruce (Picea abies), Scots pine (Pinus sylvestris) and silver fir (Abies alba), and three non‐native species, namely Austrian pine (Pinus nigra), Douglas fir (Pseudotsuga menziesii) and Atlas cedar (Cedrus atlantica).Thermal sensitivity, defined here as a decline of the maximum quantum yield of photosystem II (Fv/Fm) with increasing temperature, was measured under varying levels of heat stress and compared with the turgor loss point (πtlp) as a drought resistance trait. We calculated three different leaf thermotolerance traits: the temperature at the onset (5%) of the Fv/Fm decline (T5), the temperature at which Fv/Fm was half the maximum value (T50) and the temperature at which only 5% Fv/Fm remained (T95).T5 ranged from 38.5 ± 0.8 °C to 43.1 ± 0.6 °C across all species, while T50 values were at least 9 to 11 degrees above the maximum air temperatures on record for all species. Only Austrian pine had a notably higher T5 value than recorded maximum air temperatures. Species with higher T5 values were characterized by a less negative πtlp compared to species with lower T5.The six species could be divided into 'drought‐tolerant heat‐sensitive' and 'drought‐sensitive heat‐tolerant' groups. Exposure to short‐term high temperatures thus exhibits a considerable threat to conifer species in Central European forest production systems. [ABSTRACT FROM AUTHOR]

The rotation forestry system provides high biomass production, but could also have a negative impact on species sensitive to disturbance. Continuous cover forestry (CCF) could contribute to solving these conflicting goals, but its feasibility in nutrient limited boreal forests is yet unresolved. In a unique experiment, we simultaneously assessed the short-term effect of single-tree selection on both biomass production and biodiversity (vascular plants, bryophytes, wood-inhabiting fungi), and tested fertilization as a way to mediate growth-biodiversity trade-offs. We found that unharvested stands and stands subjected to single-tree selection had a similar species assemblage of vascular plants, bryophytes, and wood-inhabiting fungi. Fertilization increased growth by 37% and induced shifts in two understory species (favoring the grass Avenella flexuosa and disfavoring the bryophyte Hylocomium splendens). We conclude that single-tree selection may become a useful tool to enhance biodiversity in managed forests. [ABSTRACT FROM AUTHOR]