Search Results (28)

Urbanization is increasingly limiting daily human exposure to natural forest environments, highlighting the growing importance of urban green infrastructure and nature-based solutions in supporting human health and well-being. Among the mechanisms underlying the beneficial effects of forests, biogenic volatile organic compounds (BVOCs), particularly terpenes, are recognized as key contributors due to their bioactive properties and role in cultural ecosystem services related to human well-being. This study explores the potential of urban and natural trees of Pinus nigra J. F. Arnold to serve as sources of health-relevant BVOCs by examining seasonal and spatial variability in needle terpene profiles. Needle samples were collected from trees growing in an urban park and a protected natural area across three seasons (spring, summer, and autumn), and analyzed using headspace GC/MS. The study was designed as an exploratory assessment aimed at identifying general patterns of terpene variability across contrasting environments. Across all seasons and locations, α- and β-pinene consistently dominated the terpene profile, together accounting for the majority of detected compounds, and showed no significant variation in relation to site or season. In contrast, secondary monoterpenes and sesquiterpenes exhibited greater variability, contributing to context-dependent differences between environments. Despite these variations, the overall terpene composition remained relatively stable, particularly with respect to compounds previously associated with health-related effects. These preliminary findings provide insights into the potential role of Pinus nigra within urban and natural green infrastructure associated with nature-based health-oriented practices. The observed stability of health-related terpenes suggests that urban Austrian pine trees can represent a consistent source of compounds previously associated with health-related effects, although their relevance requires further investigation involving total and individual BVOC emissions measurements and human exposure assessments. Full article

We investigated bryophyte communities in mature beech forests (Fagus sylvatica L.) and Austrian pine plantations (Pinus nigra J.F. Arnold) on Fruška Gora Mountain (northern Serbia) to examine how stand structure and edaphic conditions influence trait composition and functional diversity. Environmental predictors included soil pH, soil temperature, herbaceous cover, and shrub density, while collinear structural variables were summarized using principal component analysis into a composite structural–moisture gradient. Community–environment relationships were analyzed using redundancy analysis (RDA) with restricted permutations, trait–environment coupling using RLQ and fourth-corner analysis, and functional diversity using Rao’s quadratic entropy (RaoQ). The RDA indicated significant effects of all predictors. RLQ revealed a structured multivariate coupling between bryophyte traits and environmental gradients. Functional diversity was higher in beech forests than in pine plantations, increasing with shrub density and decreasing along the structural–moisture gradient. Overall, plantation stands supported functionally more homogeneous bryophyte assemblages, highlighting the importance of stand structural complexity for maintaining forest-floor bryophytes’ functional diversity. Full article

The natural durability of wood, determined primarily by its chemistry, meets the growing demand for environmentally sustainable alternatives to toxic wood preservatives. This study assessed the relationship between the fungitoxic acetone extractive content, in particular resin acids and stilbenes, and heartwood decay resistance among fifty-two Pinus nigra J. F. Arnold clones from a clonal seed orchard in Greece. Quantitative ¹H-NMR spectroscopy was employed to determine total stilbenes (TSs) and total resin acids (TRAs) in heartwood samples, while decay resistance was evaluated through standardized weight loss tests using the brown-rot fungus Coniophora puteana (Schumach.) P. Karst. (1865) and the white-rot fungus Porodaedalea pini (Brot.) Murrill (1905). The heartwood exhibited exceptionally high extractive content (mean TAE = 304.15 mg g_dhw⁻¹), with resin acids (68.26%) predominating over stilbenes (22.31%). Regression analysis showed that the TAE and TRAs were the strongest predictors of decay resistance, explaining 33% of the variance, while stilbenes exhibited weaker and more variable associations. P. pini caused significantly higher mean weight loss (11.43%) than C. puteana (3.55%), indicating species-specific fungal aggressiveness. Among individual resin acids, abietic acids were the most influential contributors to decay resistance. The results demonstrate that resin acids have a dominant role over stilbenes in determining the natural durability of P. nigra (Black pine) heartwood and could serve as effective biochemical markers for selective breeding. Full article

Forests sustain high levels of biodiversity and essential ecosystem services, yet the impact of management practices on below-ground functioning remains difficult to assess. A comprehensive evaluation of ectomycorrhizal (ECM) fungal diversity is, therefore, required to better understand ecosystem dynamics. This study, conducted within the SelpiBioLife project, examined ECM community structure in two Pinus nigra J.F. Arnold forests in central Italy by integrating above- and below-ground sampling. Across 108 plots, ECM fruiting bodies (EMFb) were recorded during one fruiting season, and 54 soil cores were collected to characterize ECM root tips (EMRt) through morpho-anatomical analyses and ITS sequencing. Species richness and community composition were compared using rarefaction, PERMANOVA, NMDS, Mantel tests, and SIMPER analysis. A total of 70 EMFb species and 54 EMRt morphotypes were identified, displaying significant differences between sites and sampling types. EMFb surveys revealed greater richness, whereas EMRt reached sampling saturation only at one site, suggesting additional hidden diversity. Distinct community patterns were detected in ordination space, and weak correlations emerged between EMFb and EMRt dissimilarities, indicating complementary ecological information. These findings show that single-method monitoring underrepresents ECM diversity. Combined above- and below-ground investigations provide a more accurate basis for evaluating silvicultural impacts and maintaining forest ecosystem resilience. Full article

Forest litter plays a critical role in regulating the water balance of forest ecosystems, particularly in semi-arid regions where hydrological stability is under pressure due to climate change. This study investigates the maximum water holding capacity (MWHC) of litter layers across three ecologically distinct regions in Türkiye—Kastamonu, Kütahya, and Muğla—to evaluate how structural and physicochemical characteristics influence the maximum water holding capacity (MWHC) of litter layers. Litter samples classified into humus, fermenting debris, and needles were analyzed for MWHC, pH, electrical conductivity (EC), and total dissolved solids (TDSs). The results revealed that both the type of litter and regional ecological conditions significantly affect MWHC, with humus layers and moist environments exhibiting the highest water holding capacity. Additionally, MWHC showed moderate positive correlations with EC and TDS, highlighting the importance of chemical composition in water dynamics. The findings underscore that forest litter should be regarded as a dynamic and functional hydrological component, not merely residual biomass. This perspective is vital for sustainable watershed planning and adaptive forest management. The study supports the development of integrated management strategies aligned with the United Nations Sustainable Development Goals (SDGs), particularly SDG 6 (Clean Water and Sanitation), SDG 13 (Climate Action), and SDG 15 (Life on Land). Full article

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

Sustainable management of forest ecosystems requires assessing forest dynamics and project stand growth and yield in order to make strategic decisions. The size–density relationship is one of the most important measures in quantifying the carrying capacity of a forest ecosystem and determining appropriate silvicultural decisions. In this study, the maximum stand density index (SDI_max) was estimated for three common pine species in seven different ecological regions across Türkiye. Observations from 14,413 sample plots, including Calabrian pine (Pinus brutia Ten.; 6266 plots from five regions), Black pine (Pinus nigra J.F. Arnold; 6106 plots from five regions) and Scots pine (Pinus sylvestris L.; 2041 plots from three regions) forests were used in this study, covering the entire natural range of these three pine species. A mixed model with region as a random effect was developed for each species to estimate SDI_max. Results show that the slope coefficients of the self-thinning lines vary by species and are significantly different from −1.605. The Scots pine stands exhibited the highest SDI_max, followed by Black pine and Calabrian pine stands. Across seven ecological regions, the highest SDI_max was observed in the Aegean region for Calabrian and Black pine and in the East Anatolia region for Scots pine. The arid Inner Anatolia region yielded the lowest SDI_max for Black pine and Scots pine. The humid and semi-humid regions showed a higher SDI_max compared to arid regions. The three pine species studied make up almost half of the total forest area in Türkiye. The results of the study are therefore very important in terms of quantitative assessment of the country’s forests. The differences in stand dynamics of these three pine species, which are also widely distributed outside Türkiye under different ecological conditions, may also be a relevant source of information for other regions. Moreover, considering that pine stands in dry environments have a lower carrying capacity than those in humid conditions, it seems likely that pine forests in Türkiye will be affected by increasing global warming. Full article

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

The serious densification of human settlements necessitates an increase in the role and importance of green infrastructures in the overall functioning of urban ecosystems. Accordingly, the aim of the present study was to (1) assess the efficiency of air pollutant removal (potentially toxic elements) of three common ornamental trees (Tilia tomentosa Moench, Fraxinus excelsior L. and Pinus nigra J.F. Arnold) and (2) model the air quality regulatory services (removal of PM₁₀, PM_2.5 and NO₂). Three different approaches were applied—enrichment factor (EF) and metal accumulation factor (MAI) per tree species, as well as simulation modeling for the whole urban forest. The MAI values of the three studied species were found to be very similar, in the range of 22.35 to 23.08, which suggests that these species could be a good choice for planting in urban areas with worsened air quality. The highest EF values were observed for U (3–18), followed by As (1.6–2.56) and Sr (0.87–2.46). The potential of urban forests in countering air pollution was highlighted by three simulated scenarios for PM₁₀, PM_2.5 and NO₂ removal. The highest removal efficiency was calculated for evergreen species, followed by the mixed composition of deciduous (90%) and evergreen trees (10%), and the scenario with wholly deciduous trees had the lowest one. The contribution of nature-based solutions in meeting air quality standards and enhancing resilience in urban areas was clearly demonstrated. The functional complementarity of the different functional tree groups (coniferous, evergreen and deciduous broad-leaved species) was proven to be crucial for the support of both functional stabilities of the phytocenosis under diverse climatic conditions and during the change of seasonal cycles in the vegetation. Full article

This is the first report on morpho-anatomical and phytochemical differentiation of 19 native populations representing different Pinus nigra J.F.Arnold subspecies (banatica (Borbás) Novák, dalmatica (Vis.) Franco, nigra, and pallasiana (Lamb.) Holmboe) in the Balkans and Southern Carpathians. The 9 morpho-anatomical characteristics and 10 headspace volatiles of needles were analyzed with multivariate statistical analyses. The combination of results from all multivariate analyses with both types of markers revealed that P. nigra is differentiated into three groups within the studied area (the Dalmatian coast, Greece, and the rest of the Balkans with the Southern Carpathians). The first group included the population from an island in Dalmatia that corresponds to P. nigra subsp. dalmatica. The third group consisted of populations from continental Croatia, Bosnia and Herzegovina, Serbia, Romania, and Bulgaria, which corresponds to P. nigra subsp. nigra. In light of the recent molecular data that indicated that the Greek populations (the second group) represent a distinct genetic lineage of P. nigra placed between the populations from the principal area (P. nigra subsp. nigra) and Turkey (P. nigra subsp. pallasiana), one can speculate that there is one more subspecies of P. nigra in this region that corresponds to populations from Greece. Extending our analyses to Asia Minor and Crimea could bring additional results that would be valuable for clarifying the intriguing issue of the diversification of P. nigra in the eastern part of its range. Full article

Recent climate and societal changes have increased wildfire activity and prolonged the fire season in many regions of the world. The precision of fire seasonality analysis from tree-ring records can be improved by complementing the subjectively determined intra-ring position of fire scars with more precise studies of wood formation. With this aim, we monitored the wood formation dynamics of Pinus nigra J.F. Arnold (black pine) trees along a climatic gradient in western Anatolia to better understand the wood formation for the interpretation of fire seasonality. Wood microcores were collected from April to November 2021 from trees at four sites across (from north; the Black Sea climate in Bolu to the south; and the Mediterranean climate in Isparta) the areas where previous fire history reconstructions were conducted. These previous studies showed that most fires occurred during the latewood formation period. We found that matured latewood tracheids were observed between September (August) and November, thus suggesting that these fires occurred during late summer and fall. Our results show the importance of temperature and water availability for the timing of earlywood and latewood formations. These findings can be used to better inform planning activities for fire management and as a proxy to reconstruct past fire seasonality. Full article

Linden, ash, and pine are ubiquitous ornamental trees due to their ability to adapt to the urban environment. They have been key species in urban green infrastructure from more than hundreds of years and play an active role in maintaining ecosystem services. The urbanization rate in recent decades, combined with global climate change, has led to dynamic changes in the environmental factors which pose new challenges to urban vegetation. Hence, the aims of this study were as follows: (i) to track changes in the content of some elements in plant leaves after transplanting them into an urban environment; (ii) to investigate the relationship between urbanization intensity with plant traits (leaf injuries, photosynthetic activity, transpiration, stomatal conductance, and molecular changes); and (iii) to provide recommendations for improving the management and ecological functions of urban trees. To address these aims, data on urbanization intensity (according to the percentage of built-up area and traffic volume), plant performance, and intraspecific variations of silver linden (Tilia tomentosa), European ash (Fraxinus excelsior), and European black pine (Pinus nigra) were collected at four experimental plots in the city of Plovdiv (Bulgaria) during 2015–2020. The initial concentrations of some potentially toxic elements (As, Cd, Cr, Cu, Mn, Pb, V, and Zn) in the tree leaves at the beginning (prior to planting into the urban environment) and at the end of the experiment were also measured. We illustrate that the growth of urbanization intensity increased the concentrations of potentially toxic elements in tree leaves, caused leaf injuries, and enhanced the maximum photosynthetic rate but decreased the transpiration rate and stomatal conductance. At the molecular level, the percentage of polymorphic bands was also found to depend on urbanization intensity. High similarity was observed between the trees in the first three experimental plots (subjected to urbanization load), with the lowest similarity in the control plot. These findings are of high practical value for urban planners regarding how to build a new green infrastructure and how to preserve plant diversity in urban areas across urbanization gradients. Full article

In this work, the essential oil of black pine (Pinus nigra J. F. Arnold) was used for the first time as a natural, ecological, and sustainable corrosion inhibitor for the acid cleaning of carbon steel. The essential oil was extracted by hydrodistillation using a Clevenger-type apparatus, and the oil was analyzed by gas chromatography–flame–ionization detection (GC–FID) and gas chromatography–mass spectrometry (GC–MS). The most abundant components in the essential oil were α-pinene, germacrene D, (E)-cariophyllene, and β-pinene. The inhibition efficiency was determined by electrochemical methods (electrochemical impedance spectroscopy and potentiodynamic polarization measurements). The results showed that the inhibitory efficiency of the black pine essential oil increases with time, reaching the highest values after 4 h of immersion for all inhibitor concentrations. It was also shown that black pine essential oil is a mixed-type inhibitor. The contact angle measurements confirmed that the black pine essential oil, as a new natural, environmentally safe inhibitor, is able to protect carbon steel from corrosion in a 1 M HCl solution. Full article

Mediterranean forest ecosystems in Croatia are of very high significance because of the ecological functions they provide. This region is highly sensitive to abiotic stresses such as air pollution, high sunlight, and high temperatures alongside dry periods; therefore, it is important to monitor the state of these forest ecosystems and how they respond to these stresses. This study was conducted on trees in situ and focused on the four most important forest species in the Mediterranean region in Croatia: pubescent oak (Quercus pubescens Willd.), holm oak (Quercus ilex L.), Aleppo pine (Pinus halepensis Mill.) and black pine (Pinus nigra J. F. Arnold.). Trees were selected and divided into two groups: trees with defoliation of >25% (defoliated) and trees with defoliation of ≤25% (undefoliated). Leaves and needles were collected from selected trees. Differences in chlorophyll content, hydrogen peroxide content, lipid peroxidation and enzyme activity (superoxide dismutase, catalase, ascorbate peroxidase, non-specific peroxidase), and nutrient content between the defoliated and undefoliated trees of the examined species were determined. The results showed that there were significant differences for all species between the defoliated and undefoliated trees for at least one of the examined parameters. A principal component analysis showed that the enzyme ascorbate peroxidase can be an indicator of oxidative stress caused by ozone. By using oxidative stress indicators, it is possible to determine whether the trees are under stress even before visual damage occurs. Full article

This study outlines research performed on experimental plots established in forest plantations and in natural black pine forests. The objective of the study was to determine the habitat factors that have the greatest impact on the growth and development of natural black pine forests and black pine forests plantations upon the return of climatozonal vegetation. Plots 625 m² in size were selected and vegetation inventories made, and the structural elements of black pine plantations examined. Multivariate analysis found that elevation and slope were the two variables that had the highest positive correlation with the floristic composition of the vegetation. Furthermore, one of the goals was to determine the differences with regard to reforestation with black pine. The analysis of the isolated experimental plots showed a clear grouping of plots according to habitat factors. The differences in the synecological factors in the research area resulted in the presence of sub-Mediterranean, epi-Mediterranean and eu-Mediterranean elements within the black pine forest plantations. This also reduces the risk of the occurrence and development of large wildfires. Full article