Search Results (189)

This study investigates the potential of Pinus pinaster subsp. atlantica bark, a forestry by-product from northern Portugal, as a source of phenolic compounds with strong antioxidant properties. Microwave-assisted extraction (MAE) was used to optimize recovery, assessing the effects of solvent composition (water, ethanol, and 50:50 water–ethanol), extraction time (15 or 30 min), and temperature (90, 110, or 130 °C) using a one-variable-at-a-time approach. High-Performance Liquid Chromatography (HPLC) profiling characterized the polyphenol composition. The results showed that solvent choice strongly influenced extract composition and bioactivity, with hydroethanolic and ethanolic extracts exhibiting the highest antioxidant activities in DPPH, ABTS, and ORAC assays. Optimal conditions—50:50 water–ethanol, 130 °C, 15 min—yielded 11.13% (w/w) extract, 3.10 mg GAE/mL total phenolics, and 2.01 mg CE/mL condensed tannins, comparable to commercial extracts such as Pycnogenol^®. MAE proved effective, rapid, and solvent-efficient, enhancing phenolic recovery without degrading extract quality. These findings highlight the potential of P. pinaster bark extracts for biomedical, nutraceutical, and cosmetic applications, supporting the sustainable valorization of forestry residues and aligning with circular economy principles. Full article

Background/Objectives: Anxiety, agitation, and mood disturbances are increasingly common among children and adolescents. Given the limitations of conventional pharmacological treatments in the pediatric population, particularly for subthreshold or mild conditions, interest in complementary approaches such as phytotherapy is growing. This review aims to critically evaluate the clinical evidence supporting the use of herbal medicines and botanical food supplements for mental health symptoms in youths and to explore the pharmacological basis of their activity. Methods: A systematic search was conducted across main databases for clinical trials involving herbal products for psychologically related symptoms in children and adolescents. Eligible studies included those using registered herbal medicines, as well as authorized food supplements, that evaluated behavioral or cognitive outcomes. In addition, bioinformatic analyses were performed on selected phytocompounds to predict their molecular targets. Results: Twenty-nine clinical trials were identified, including eighteen targeting pathological conditions (notably attention deficit/hyperactivity disorder (ADHD), anxiety, and depression) and eleven addressing borderline symptoms such as nervous agitation, restlessness, or sleep disturbances. Herbal products showing clinical promise include Bacopa monnieri (L.) Wettst., Crocus sativus L., Ginkgo biloba L., Hypericum perforatum L., Lavandula angustifolia Mill., Melissa officinalis L., Panax ginseng C.A. Meyer, Passiflora incarnata L., Pinus pinaster Aiton, Valeriana officinalis L., and Withania somnifera (L.) Dunal. Bioinformatic predictions revealed polypharmacological activity profiles involving neuroinflammatory, neuroprotective, and neurotransmitter-related pathways. Conclusions: This review highlights both the potential and the current limitations of herbal products in pediatric mental health care. Evidence supports their use for selected indications, provided that standardized preparations and clinical oversight are ensured. Further research is essential, particularly to inform dosing, safety, and integrative care strategies. Full article

Portugal’s commitment to carbon neutrality by 2050 has intensified the search for renewable energy alternatives, with biomass gasification emerging as a promising pathway for hydrogen production. This comprehensive review analyzes the potential of 39 Portuguese biomass species for gasification processes, based on extensive laboratory characterization data including proximate analysis, ultimate analysis, heating values, and metal content. The studied biomasses encompass woody shrubland species (matos arbustivos lenhosos), forest residues, and energy crops representative of Portugal’s diverse biomass resources. Results indicate significant variability in gasification potential, with moisture content ranging from 0.5% to 14.9%, ash content from 0.5% to 5.5%, and higher heating values between 16.8 and 21.2 MJ/kg. Theoretical hydrogen yield calculations suggest that Portuguese biomasses could produce between 85 and 120 kg H₂ per ton of dry biomass, with species such as Eucalyptus globulus, Pinus pinaster, and Cytisus multiflorus showing the highest potential. Statistical analysis reveals strong negative correlations between moisture content and hydrogen yield potential (r = −0.63), while carbon content shows positive correlation with gasification efficiency. The comprehensive characterization provides essential data for optimizing gasification processes and establishing Portugal’s biomass-to-hydrogen production capacity, contributing to the national hydrogen strategy and renewable energy transition. Full article

Forest fires are recurrent in Spain and affect tree species in different ways. Fire incidence in the main Spanish forest species, both native and alien, is estimated in this study based on actual fire occurrences. Indices of presence, burned area, fire extent, frequency, and recurrence were calculated for each species, and with them, fire incidence indices were obtained. Significant fire incidence was detected in Pinus canariensis, P. pinaster, Eucalyptus globulus, Quercus robur, Betula spp., Castanea sativa, Pinus radiata, and Quercus pyrenaica. Most of the species with the highest fire incidence are not located in the areas with the highest climatic hazard. There is limited correlation between flammability and fire extension, and this is not significant when considering fire incidence. The relationship between fire incidence and conifers is valid in absolute terms, but only partially in relative terms. Similarly, there is no general relationship between relative fire incidence and species with a natural or reforested origin. Some native hardwood species have unexpectedly high incidence, probably due to collateral damage caused by fires in nearby pine and eucalyptus stands. The fire incidence index of forest species is useful for forest management and for protecting species that are suffering severely from fire effects. Full article

Accurate biomass estimation is important for forest management and climate change mitigation. This study evaluates the potential of using LiDAR (Light Detection and Ranging) data, acquired through Unmanned Aerial Vehicles (UAVs), for estimating above-ground and total biomass in Eucalyptus globulus and Pinus pinaster stands in central and northern Portugal. The acquired LiDAR point clouds were processed to extract structural metrics such as canopy height, crown area, canopy density, and volume. A multistep variable selection procedure was applied to reduce collinearity and select the most informative predictors. Multiple linear regression (MLR) models were developed and validated using field inventory data. Random Forest (RF) models were also tested for E. globulus, enabling a comparative evaluation between parametric and machine learning regression models. The results show that the 25th height percentile, canopy cover density at two meters, and height variance demonstrated an accurate biomass estimation for E. globulus, with coefficients of determination (R²) varying between 0.86 for MLR and 0.90 for RF. Although RF demonstrated a similar predictive performance, MLR presented advantages in terms of interpretability and computational efficiency. For P. pinaster, only MLR was applied due to the limited number of field data, yet R² exceeded 0.80. Although absolute errors were higher for Pinus pinaster due to greater biomass variability, relative performance remained consistent across species. The results demonstrate the feasibility and efficiency of UAV LiDAR point cloud data for stand-level biomass estimation, providing simple and effective models for biomass estimation in these two species. Full article

Climate models forecast warmer winter conditions, which could lead to an earlier spring xylem phenology in trees. Localized stem heat experiments mimic this situation and have shown that stem warming leads to an earlier cambial resumption in evergreen conifers. However, there are still few comprehensive studies comparing the responses to stem heating in coexisting conifers and hardwoods, particularly in drought-prone regions where temperatures are rising. We addressed this issue by comparing the responses (xylem phenology, wood anatomy, growth, and sapwood concentrations of non-structural carbohydrates—NSCs) of two pines (the Eurosiberian Pinus sylvestris L., and the Mediterranean Pinus pinaster Ait.) and a ring-porous oak (Quercus pyrenaica Willd.) to stem heating. We used the Vaganov-Shashkin growth model (VS model) to simulate growth phenology considering several emission scenarios and warming rates. Stem heating in winter advanced cambial phenology in P. pinaster and Q. pyrenaica and enhanced radial growth of the three species 1–2 years after the treatment, but reduced the transversal lumen area of earlywood conduits. P. sylvestris showed a rapid and high growth enhancement, whereas the oak responded with a 1-year delay. Heated P. pinaster and Q. pyrenaica trees showed lower sapwood starch concentrations than non-heated trees. These results partially agree with projections of the VS model, which forecasts earlier growth onset, particularly in P. pinaster, as climate warms. Climate-growth correlations show that growth may be enhanced by warm conditions in late winter but also reduced if this is followed by dry-warm growing seasons. Therefore, forecasted advancements of xylem onset in spring in response to warmer winters may not necessarily translate into enhanced growth if warming reduces the hydraulic conductivity and growing seasons become drier. Full article

Understanding how regional and local climate variability drive radial growth in trees is necessary to assess the climate-warming mitigation potential of forests. However, tree species occurring in the same region differently respond to climate variability, including climate extremes such as droughts, depending on soil–moisture gradients (hydrological niche). We analyzed a tree-ring network built in a mountainous area (Sierra de Gredos, central Spain) to compare climate–growth responses between species and sites located along soil–moisture gradients. Tree-ring methods were applied to six tree species, and sampled in twelve sites, including conifers (Pinus pinaster) and broadleaves (Quercus pyrenaica, Quercus robur, Quercus ilex, Celtis australis, and Prunus lusitanica). Series of growth indices were correlated with climate variables and climate indices (NAO, North Atlantic Oscillation). The radial growth of most species was enhanced by high growing-season precipitation, linked to negative NAO phases. The influence of precipitation on growth variability strengthened as site elevation decreased, particularly in the case of C. australis and oak species. The topographical modulation of climate–growth couplings indicates that the hydrological niche drives species responses to water shortage. Tree-ring data could be used to refine time-dependent hydrological niches. Full article

A possible tactic to survey and control Pine Wilt Disease is the use of semiochemical-baited traps to capture the insect-vector, the pine sawyer Monochamus galloprovincialis (Olivier) (Coleoptera: Cerambycidae). The most common chemical lure used is the Galloprotect Pack, which includes the aggregation pheromone ([2-undecyloxy] ethanol), a host monoterpene (α-pinene), and bark-beetle pheromones (ipsenol and 2-methyl-3-buten-1-ol). This lure also attracts non-target species, including bark beetles (Coleoptera: Curculionidae: Scolytinae) that use ipsenol (Ips sexdentatus (Boerner)) and 2-methyl-3-buten-1-ol (Orthotomicus erosus (Wollaston)) as pheromones, but also large numbers of their natural enemies, Temnoscheila caerulea (Olivier) (Coleoptera: Trogossitidae), Aulonium ruficorne (Olivier) (Coleoptera: Colydiidae), and Thanasimus formicarius (L.) (Coleoptera: Cleridae), and other saproxylic insects (Coleoptera: Cerambycidae). These catches cause a decrease in biodiversity of the forest insect communities, and the removal of predatory insects may favour bark beetle outbreaks. Thus, our project objective was to test trap modifications to try to reduce catches of non-target insects. Modifying the multifunnel trap’s collection cup by placing a 0.5 cm mesh in the drainage hole allowed the escape of all predator beetles (Cleridae, Trogossitidae, Colydiidae, and Histeridae) in 2020, and retained only two Trogossitidae in 2021, against 249 specimens caught in the non-modified collection cup. This simple modification thus allowed the escape of almost all predators, while maintaining the traps’ efficiency at catching the target species, M. galloprovincialis. Full article

The use of chemical stimulants in resin tapping is essential for prolonging the resin flow and enhancing production. Traditional stimulants, primarily composed of sulfuric acid, pose concerns related to workplace safety, environmental impact, and tree health. In this study, we compared alternative stimulant pastes containing ethrel, salicylic acid, and citric acid with the traditional Spanish and Brazilian stimulant pastes with higher contents of sulfuric acid. We tapped Pinus pinaster seedlings with five different stimulants, using untreated and mechanically wounded plants as controls. The resin yield, tree growth, and physiological parameters were compared. The pines stimulated with citric acid released ca. 50% more resin, while ethrel and salicylic acid yielded similar amounts to the traditional paste, suggesting their potential as viable alternatives. Although all stimulants reduced the seedling growth, no significant differences were observed in the midday water potential or stomatal conductance. The internal resin accumulation and resin canal density were strongly correlated with the total resin production, and more-acidic pastes tended to cause xylem damage and resin retention. Our findings suggest that moderate acidity is sufficient to trigger resin biosynthesis and release, and that safer, less corrosive formulations, like citric acid, may provide viable, safer, and more sustainable alternatives to conventional stimulants. While the results from the seedlings provide a rapid and cost-effective screening tool, anatomical and physiological differences from mature trees should be considered when extrapolating findings to operational settings. Full article

The pine cone is an important forest product for the Portuguese economy. However, it is associated with environmental impacts, such as the generation of waste and the increased risk of forest fires. The objective of this research is to valorise waste from the production of Pinus pinaster Aiton in the form of natural dyes. The pine cone extracts were characterised in different alkaline solutions (1%, 5% and 10% NaOH) in order to evaluate the dyeing process on cotton knitwear, using the CIELab coordinates. The dyed samples were also subjected to light and water fastness tests. The extracts showed an increase in solids content with increasing alkalinity and a reduction in antioxidant content. The phenol content increased in the extract with 5% but decreased with the 10% concentration. All the dyes expressed a pink colour but with different shades. About the L* coordinate (luminosity), the colours became lighter as the NaOH increased. In the a* coordinate, all the samples had a reddish colour, and, in the b* coordinate, all the samples had a yellowish colour. About light and water fastness, all the samples lost colour, but in the water test, it was not noticeable. Full article

The maritime pine (Pinus pinaster) is the main conifer species in Portugal, occurring mainly in the central and northern regions of the country. In addition to its environmental significance, it plays an important socio-economic role, supported by a robust forest sector. In the face of climate change driven by the release of CO₂ into the atmosphere, forests play an essential role in mitigating these changes by storing large amounts of carbon in their biomass. This study assesses the impact of forest management, focusing on thinning, on carbon accumulation in naturally regenerating maritime pine forests in the municipality of Boticas, Portugal and compares scenarios with and without forest intervention. To simulate forest growth scenarios, the Modispinaster software is used, and through mathematical models adjusted for the species and input of initial field data, it generates scenarios of forest evolution regarding biomass and carbon accumulation. Additionally, it allows for the visualization of the forest’s dendrometric characteristics throughout the cycle, enabling the creation of the carbon balance and its analysis across multiple scenarios. The results demonstrate that management based on thinning increases carbon retention, reducing early mortality and promoting the growth of larger diameter trees. Although natural forests initially accumulate more carbon, the reduction in competition in managed forests allows for greater carbon accumulation from the 24th year onwards, reaching 178 tons at the end of the cycle, in contrast to 143 tons in unmanaged areas. The carbon balance result in the unmanaged (natural) forest was negative (−18 tons), while in the managed forest, the result was positive (54 tons). This supports the thesis that thinning, although more intense and less frequent than mortality events, is more effective than the absence of interventions. Thinned forests optimize the carbon balance in Pinus pinaster, improving long-term retention by reducing competition and mortality. Managed forests show a positive carbon balance, highlighting the importance of sustainable management in mitigating climate change and strengthening ecological resilience. Full article

Citric acid (CA), a naturally occurring compound in fruits, mainly citrus, has gained attention for its eco-friendly potential in wood modification. Through esterification, citric acid reacts with wood polymers to form bonds that improve adhesion, dimensional stability, and durability while reducing moisture absorption and susceptibility to decay. This study evaluated the efficacy of CA as an eco-friendly wood treatment. Wood samples were treated with solutions at varying concentrations (5%, 10%, and 15%) and assessed for dimensional stability, mechanical properties, biological resistance, and ecotoxicity. CA treatments significantly improved dimensional stability, with higher concentrations yielding greater weight percent gain (WPG) and anti-swelling efficiency (ASE). Biological tests demonstrated exceptional termite resistance, with no survival and minimal mass loss in treated samples at higher concentrations. Similarly, fungal resistance improved, as citric acid inhibited fungal growth. Ecotoxicity tests showed relatively low phytotoxicity, with some decrease in germination indices (GI) at higher CA concentrations. These findings highlight CA as a sustainable wood treatment for enhanced durability and biodegradation resistance in construction and outdoor applications. Full article

The oleoresin and volatile fraction produced by conifers, such as Pinus pinaster, play a crucial role in plant defence, acting as precursors to resin acids and adapting in response to environmental stress or pathogen attacks. Abietadiene (abieta-7,13-diene), the biosynthetic precursor to abietic acid, has been identified as the most abundant compound in extracts from pinewood nematode (PWN)-infected P. pinaster trees. As abietadiene is not commercially available, this study aimed to achieve, for the first time, its isolation, structure elucidation, and detailed characterization from readily available forestry residues. Abietadiene was successfully isolated using thin-layer chromatography (TLC), and its purity and identity were evaluated using multiple analytical techniques: gas chromatography (GC), liquid chromatography (LC), nuclear magnetic resonance (NMR), and Fourier-transform infrared spectroscopy (FTIR). GC analysis indicated a purity of over 70% for the isolated compound, while LC provided the higher purity value of 98%. The identity of abietadiene was unequivocally confirmed through LC, FTIR, and NMR analysis. This work represents the first isolation and comprehensive characterization of abietadiene from a natural source, making detailed chemical data on this compound available to the scientific community. These findings may be used for future studies on the biological interactions and ecological roles of abietadiene, particularly in the context of plant defence and pathogen resistance. Full article

The pinewood nematode (PWN), Bursaphelenchus xylophilus, infects susceptible pine species and causes pine wilt disease (PWD). The first visible symptoms are yellowing and drooping of pine needles due to compromised biochemical reactions of photosynthesis, as a result of damage to the tree’s water column. In vitro cultures are useful tools to study minute biochemical changes because they easily enable reproducibility and genetic homogeneity. In the present work, in vitro maritime pine (Pinus pinaster) shoot cultures were used to simulate PWD, by infecting with PWN in asepsis. Changes in the levels of photopigments, i.e., chlorophyll a and b, carotenoids, and stress related anthocyanins, were followed through spectrophotometry. Infection with the PWN led to a 30% decrease in shoot concentrations of chlorophyll a and a 50% reduction on chlorophyll b. Concentrations of carotenoids increased by 70%, while for anthocyanins no statistically significant changes were observed. PWN phytophagy seems to trigger chlorophyll degradation and production of carotenoids, most probably as a response to oxidative stress. This preliminary study allows gauging the impacts of PWN infection in pine, at the initial stages of PWD, as a contribution to developing, for example, an early detection tool for this phytoparasite. Full article

Land use and land cover (LULC) studies, particularly those focused on mapping forest species using Sentinel-2 (S2A) data, face challenges in delineating and identifying areas of heterogeneous forest components with spectral similarity at the canopy level. In this context, the main objective of this study was to compare and analyze the feasibility of two classification algorithms, K-Nearest Neighbor (KNN) and Random Forest (RF), with S2A data for mapping forest cover in the southern regions of Portugal, using tools with a free, open-source, accessible, and easy-to-use interface. Sentinel-2A data from summer 2019 provided 26 independent variables at 10 m spatial resolution for the analysis. Nine object-based LULC categories were distinguished, including five forest species (Quercus suber, Quercus rotundifolia, Eucalyptus spp., Pinus pinaster, and Pinus pinea), and four non-forest classes. Orfeo ToolBox (OTB) proved to be a reliable and powerful tool for the classification process. The best results were achieved using the RF algorithm in all regions, where it reached the highest accuracy values in Alentejo Central region (OA = 92.16% and K = 0.91). The use of open-source tools has enabled high-resolution mapping of forest species in the Mediterranean, democratizing access to research and monitoring. Full article