Explore the vast range of titles available.

Forest dynamics are undergoing profound alteration due to the fact that climate change is increasing the frequency and severity of abiotic and biotic forest disturbances. Because of the unpredictable nature of the drought periods and the variation in their severity, Mediterranean forests are typically more vulnerable. Mediterranean Pinus pinaster forests are showing decay symptoms linked to climate change. There is clear evidence that promoting mixtures can serve as an effective forest adaptation strategy. In this regard, we sought to better understand the responses of P. pinaster radial growth dynamics to various factors, in both mixed and pure forest stands, and provide valuable insights into P. pinaster dynamics when mixed with P. sylvestris. In this study, we examined the variation of intra-annual cumulative radial increment patterns in response to the climate of P. pinaster between pure and mixed stands with P. sylvestris. Using data from band dendrometers collected over five consecutive climatically distinct years (2016–2020), a nonlinear mixed-effect model approach was used to analyze the differences in intra-annual cumulative radial increment patterns for P. pinaster between years in mixed and pure stands. The intra-annual radial increment pattern of P. pinaster showed significant year-to-year variation and varied with tree size, with greater increment in larger trees. Trees in mixed stands had a higher mean radial increment compared to corresponding ones in pure stands. Increased summer maximum temperatures negatively affected tree cumulative annual increment regardless of composition, but with a lower impact on trees in pure stands. Spring precipitation increased the length of the growing season, while higher spring maximum temperatures triggered an earlier inflection point. Our results highlight the high plasticity of P. pinaster in adapting to varying intra- and inter-annual environmental conditions and competition with other species and suggest that promoting mixtures with P. sylvestris may be an interesting management strategy for adaptation to climate change.

Natural compounds from agro-food by-products have fostered interest in food industries. The aim of this study was to unravel potential uses for Pinus pinaster bark extracts (PBE). As functional features of this type of extracts are usually attributed to phenolic compounds, the extraction process was studied. Different PBEs were achieved, with high content in phenolic compounds, using different water/ethanol combinations as a solvent. These PBEs were chemically characterized, and their bioactivity and in vitro cell viability were evaluated. Extracts obtained with hydroethanolic solvents had higher content in phenolic and flavonoid compounds. All the PBEs presented high antioxidant, antibacterial and antihyperglycemic activities. Moreover, PBEs have low cytotoxicity and a selective activity against cancer cells as these were negatively affected. These features may allow the extracts to be used in food formulation and processing (as preservatives, antioxidants or bioactive ingredients), but they showed also potential for the pharmaceutical or nutraceutical sectors.

Pinus Pinaster Ait. is a softwood species indigenous of the South West of Europe, broadly spread alongside the Mediterranean Sea and present worldwide. Pinus Pinaster Ait. (ssp. Atlantica ) is largely used in industrial applications including construction and buildings in the Southwest of France as it has widely grown across the whole area. However, very often, Pinus Pinaster Ait.-based product design strategies make use of properties of generic softwood species due to the lack of a proper database (or review) on the topic. This review article aims to exhaustively present the consistent scientific literature on Pinus Pinaster Ait. properties focusing on its physical, hygrical, thermal and mechanical properties. Indeed, a vast literature exists, laid out across a wide range of years and countries.

Drought constrains tree growth in regions with seasonal water deficit where growth decline can lead to tree death. This has been observed in regions such as the western Mediterranean Basin, which is a climate-warming hotspot. However, we lack information on intra- and inter-specific comparisons of growth rates and responses to water shortage in these hotspots, considering tree species with different drought tolerance. We sampled several sites located in north-eastern Spain showing dieback and high mortality rates of three pine species (Pinus sylvestris, Pinus pinaster, Pinus halepensis). We dated death years and reconstructed the basal area increment of coexisting living and recently dead trees using tree ring data. Then, we calculated bootstrapped Pearson correlations between a drought index and growth. Finally, we used linear mixed-effects models to determine differences in growth trends and the response to drought of living and dead trees. Mortality in P. sylvestris and P. pinaster peaked in response to the 2012 and 2017 droughts, respectively, and in sites located near the species’ xeric distribution limits. In P. halepensis, tree deaths occurred most years. Dead trees showed lower growth rates than living trees in five out of six sites. There was a strong growth drop after the 1980s when climate shifted towards warmer and drier conditions. Tree growth responded positively to wet climate conditions, particularly in the case of living trees. Accordingly, growth divergence between living and dead trees during dry periods reflected cumulative drought impacts on trees. If aridification continues, tree drought mortality would increase, particularly in xeric distribution limits of tree species.

This study explores the antioxidant, antibacterial, and cytocompatibility properties of aqueous Pinus pinaster bark extract (PBE). PBE was prepared using two solvent systems—100% distilled water and 1% DMSO in aqueous solution—at a solid-to-liquid ratio of 1:20 (w/v), following ISO guidelines. Extract characterization included yield determination, FTIR analysis, quantification of total phenolic (TPC) and flavonoid (TFC) contents, and assessment of antioxidant activity using four complementary methods: free radical scavenging (DPPH and ABTS), metal ion reduction (FRAP), and a competitive reaction assay (ORAC). The phenolic compound profile was further examined by HPLC-DAD. The results indicated that the two extracts exhibited comparable values across all evaluated parameters when expressed per gram of PBE. The TPC and TFC were approximately 400 mg GAE (gallic acid equivalents)/g PBE and 92 mg CE (catechin equivalents)/g PBE, respectively. Antioxidant capacity values were about 880, 1030, 3210, and 585 mg TE (Trolox equivalents)/g PBE for the DPPH, ABTS, ORAC, and FRAP assays, respectively. Furthermore, in both extracts, the phenolic and flavonoid contents exhibited strong positive correlations with antioxidant activity across all four chemical assays. The 100% aqueous extract was additionally evaluated for antibacterial activity and cytocompatibility with eukaryotic cells. Compared to the control, the extract demonstrated IC50 values of 0.304, 0.678, and 0.845 mg/mL PBE for the inhibition of Staphylococcus aureus, Escherichia coli, and fibroblast cells, respectively. Antioxidant and antibacterial activities showed a positive association within concentration ranges that remained non-cytotoxic to fibroblasts. Overall, these findings indicate that the aqueous PBE retains cytocompatibility across a wide concentration range while maintaining both antioxidant and antibacterial activities, underscoring its potential for biological applications involving direct contact with eukaryotic cells.

Key message This paper provides individual tree models to estimate crown variables in maritime pine ( Pinus pinaster Aiton.). The estimation of crown variables, especially height to the base of the crown and crown length, is essential for forest fire simulators that require the calculation of canopy bulk density, a measure that relates leaf weight and canopy volume. Context The numerous forest fires that have occurred in the Portuguese forest ecosystems over the past decades justify, by themselves, the importance of estimating crown variables such as crown ratio, crown length and height to the base of the crown, which are also frequently used as predictors in individual tree models’ components. Aims A compatible system of equations to predict crown variables was developed for maritime pine ( Pinus pinaster Aiton.) in Portugal. Methods A database with a long time-series of measurements covering a wide variety of situations was used to fit models to estimate crown ratio, crown length and height to the base of the crown. To guarantee accuracy and compatibility among crown variables the models were developed as a compatible system of equations fit using seemingly unrelated regression. The parameters of the functions were expressed as a function of tree, site and stand variables and inter-tree competition. Results The system of equations for height to the base of crown and crown length, both accurate and consistent, is based on a set of parameters describing tree age, height and slenderness, basal area, dominant height and a distance-independent competition index, the ratio tree size/average tree size. Conclusion The equations developed in this study describe how the tree and stand variables control height to the base of the crown, crown ratio and crown length. These variables depend on tree age and dominant height, with crown ratio decreasing as trees and stands get older. Tree slenderness has a positive effect, with shorter crowns in trees that are closer to a cylinder (lower d/h ratio). Stand density implies shorter crowns and, within a stand, trees under lower competition (higher values of d/dg ) have longer crowns.

Pinus pinaster forestry occupies >20% of the forest ecosystem area in the continental territory of Portugal with a high impact on the national economy. This species’ major derived non-wood product is oleoresin, the raw material for rosin production. Rosin comprises mainly a blend of resin acids and has broad industrial and pharmaceutical applications. Oleoresin production in Portugal has been progressively reduced due to low-cost producers in other countries; currently, it reaches only 2% of the existing P. pinaster trees. To support this value chain, the chemical fingerprint of rosin derived from the national forest requires focused analysis. In the present study, we collected oleoresin within seven geographically distinct pure P. pinaster forests in two consecutive collection years. A high-resolution nuclear magnetic resonance (NMR) method was used to quantify the diversity of resin acids in the corresponding rosin samples. Overall, the acquired data highlighted that the profile of resin acids in P. pinaster rosin produced in Portugal is highly regular, regardless of the forest location, having as the major constituents abietic acid and dehydroabietic acid. The diversity of resin acids is possibly influenced, to a minor extent, by some edaphoclimatic factors.

The pinewood nematode (PWN) Bursaphelenchus xylophilus is the causal agent of the pine wilt disease (PWD) and represents one of the major threats to conifer forests. The detection of the PWN in Portugal, associated with Pinus pinaster , increased the concern of its spread to European forests. Despite its susceptibility to PWD, genetic variability found among P. pinaster populations has been associated with heritable PWD resistance. Understanding the mechanisms underlying tree resistance constitutes a valuable resource for breeding programs toward more resilient forest plantations. This study investigated changes in anatomy, chlorophyll a fluorescence (ChlF), and primary metabolism in susceptible and resistant P. pinaster half-sib plants, after PWN inoculation. Susceptible plants showed a general shutdown of central metabolism, osmolyte accumulation, photosynthetic inhibition, and a decrease in the plant water status. The ChlF transient rise (OJIP curve) revealed the appearance of L- and K-bands, indicators of environmental stress. In contrast, resistant plants revealed a regulated defense response and were able to restrict PWN migration and cellular damage. Furthermore, the accumulation of γ-aminobutyric acid (GABA) and succinate suggested a role of these metabolites in PWD resistance and the possible activation of the GABA shunt. Altogether, these results provide new insights to the role of primary metabolism in PWD resistance and in the selection of resistant phenotypes for disease mitigation.

The effect of fire severity on growth and ecophysiological responses was evaluated in four burned sites of Vesuvio National Park, Southern Italy. After the wildfire of 2017, when over 1300 hectares of vegetation, mainly woods, were destroyed, four sites were selected according to the different degree of fire severity and a multidisciplinary approach based on tree rings, stable isotopes and percentage of crown scorched or consumed was applied. All the sampled trees in the burned sites showed a decrease in tree growth in 2017, in particular in the latewood at high-severity site. The dendrochronology analyses showed that several individuals experienced and endured higher fire severity in the past compared to 2017 fire. Further δ C and δ O underlined the ecophysiological responses and recovery mechanisms of , suggesting a drastic reduction of photosynthetic and stomata activity in the year of the fire. Our findings demonstrated that growth reduction is strictly linked to the percentage of crown scorch and that even trees with high level of crown scorched could survive. In all the burned sites the high temperatures and the time of exposure to the flames were not sufficient to determine the death of the cambium and all the trees were able to complete the 2017 seasonal wood formation. This data can contribute to define guidelines to managers making post-fire silvicultural operations in pine forest stands in the Mediterranean Basin.

Many studies highlight the role of mixed versus monospecific forests to supply numerous ecosystem services. Most reports of positive mixture effects on carbon storage focus on mixtures that combine tree species with contrasting traits, but little is known on the effect of mixing species that are expected to behave quite similarly as they belong to the same genus. In this study, we assessed the effect of mixed versus monospecific stands of Pinus sylvestris and P. pinaster on carbon storage and exchangeable cations along the soil profile, based on research with six triplets in the northern Iberian Peninsula (Spain). One soil pit of at least 40 cm depth was dug at each plot for organic and mineral horizons characterization. Two trends were found: in the topsoil, higher values of carbon stock and total organic carbon were found in P. sylvestris stands, lower in P. pinaster stands and intermediate in mixed stands; this pattern was related to the C/N ratio of the forest floor. In the intermediate soil layers, it tends to be higher in mixed stands and is related to percentage of fine roots and to the greater thickness of the first mineral horizon. Differences in soil exchangeable cations among stands were related to the total organic carbon content. These results improve our understanding of the mechanisms underlying soil carbon accumulation in mixed stands and emphasize the use of mixtures as a strategy to combat climate change, due to the advantage in the accumulation of carbon in the subsoil layers.Graphical Abstract