Search Results (138)

The aim of this study was to evaluate the suitability of eight softwood species most commonly used by Greek timber industries, including furniture manufacturers and companies producing roundwood, sawn timber, and plywood. The analysis was based on integrated Multi-Criteria Decision Analysis (MCDA), using a combined approach of the PROMETHEE method and the Analytical Hierarchy Process (AHP), taking into consideration some important criteria that affect timber quality. According to the PROMETHEE complete ranking, Aleppo pine (Pinus halepensis Mill.) achieved the best performance under the selected criteria among the examined softwood species, underlying the importance of Aleppo pine to the Greek timber industry. Our findings could be highly beneficial to the wood industry, promoting the recovery and advancement of the forest sector in general, taking into account that sustainable wood supply is lower than the total biomass available in Europe. Policymakers should prioritize the selection of conifer tree species that can strengthen Greece’s forestry sector, promote sustainable management practices, and increase the economic value derived from the country’s diverse forest resources. Full article

Forests and scrubland comprise a large proportion of terrestrial ecosystems and, due to the long lifespan of trees and shrubs, their capacity to grow and store carbon as lasting woody tissues is particularly sensitive to warming-enhanced drought occurrence. Climate change may trigger a transition from forests to scrubland in many drylands during the coming decades due to the higher resilience of shrubs. However, we lack standardized frameworks to compare the response to drought of woody plants. We present a framework and develop an index to estimate the drought-induced vulnerability (DrVi) of trees and shrubs based on the radial growth trajectory and the response of growth variability to a drought index. We used tree-ring width series of three tree (Pinus halepensis Mill., Juniperus thurifera L., and Acer monspessulanum L.) and three shrub (Juniperus oxycedrus L., Pistacia lentiscus L., and Ephedra nebrodensis Tineo ex Guss.) species from semi-arid areas to test this framework. We compared the DrVi values between species and populations and explored their temporal changes. Across species, the strongest DrVi values were found in declining P. halepensis stands and J. oxycedrus from the same site, while the lowest DrVi values were found in A. monspessulanum, P. lentiscus, and E. nebrodensis. Across populations, J. oxycedrus presented higher vulnerability in one of the dry sites. The P. halepensis declining stand showed a steady increase in DrVi value after the 1980s as the climate shifted toward warmer and drier conditions. We conclude that the DrVi allows comparing species and populations using a standardized general framework. Full article

In the last decades the impact of wildfires on forest ecosystem and human assets has steadily increased. Forest operations can help to reduce the spread rate and intensity of wildfires by limiting the biomass available for combustion. Fuel removal is mainly done with preventive silviculture works which, in the Mediterranean basin, typically feature a negative economic balance. The introduction of small-sized forest machines may enhance efficiency and safety of such operations. The study compares the performance of the common motor-manual work system with an innovative machine performing both harvesting and forwarding of biomass. The study took place in a post-fire regenerated Pinus halepensis Mill. area with high fuel accumulation. Three plots were selected to represent the main development stages of this type of forest, respectively with a density of about 1700, 5000 and 9600 trees∙ha⁻¹. The machine showed a clear advantage over the manual system with the lower and intermediate trees density, where the capacity to valorize the biomass reduced the overall balance per hectare respectively to 19% and 50% of the alternative. This allows to cover the whole operation with the local public subsidy, unlike the manual system. With the higher density, the overall balance is unfavorable for both work systems and different solutions should be tested. Full article

Moroccan vegetation faces significant pressure particularly from human activities and climate change, while most ecosystems lack detailed assessments. Phytoecological studies and species assessments are implemented using vegetation sampling, analysis of climate data, geological substrate maps, and the Digital Elevation Model (DEM). The study area hosts 565 plant species distributed into 74 families, with Asteraceae being the most abundant family, representing 17.7%. In addition, the correspondence analysis test demonstrates that species are grouped into six distinct blocks. Block 1 comprises a set of Quercus ilex forests. Block 2 encompasses Juniperus phoenicea lands and transition zones between Quercus ilex and Juniperus phoenicea. Block 3 represents Pinus halepensis forests and pine occurrences within Quercus ilex and Juniperus phoenicea stands. Block 4 indicates the emergence of xerophytic species alongside the aforementioned species; it forms the upper limits of Blocks 1, 2, and 3. Block 5 corresponds to formations dominated by Juniperus thurifera in association with xerophytes. Block 6 groups together a set of xerophytic species characteristic of high mountain environments. Additionally, Quercus ilex colonizes the subhumid zones and prefers limestone substrates, Juniperus phoenicea and Tetraclinis articulata, and Pinus halepensis occupies the hot part of the semi-arid in limestone, clays, and conglomerates, while the Juniperus thurifera and xerophytes inhabit the cold parts and limestone substrates. The thermo-Mediterranean vegetation level occupies low altitudes, dominated by Tetraclinis articulata, Juniperus phoenicea, and Olea europaea. The meso-Mediterranean level extends to intermediate altitudes, dominated by Quercus ilex and Juniperus phoenicea. While the supra-Mediterranean level is dominated by Quercus ilex, Arbutus unedo, and Cistus creticus. The mountain Mediterranean level, located in the high mountains, is dominated by Juniperus thurifera associated with xerophytes. Finally, the oro-Mediterranean level, found at extreme altitudes, is dominated by xerophytes. Some species within this region are endemic, rare, and threatened. Consequently, the implementation of effective conservation and protection policies is recommended. Full article

(1) Background: The present study examines the effects of fire on the ecosystem services of forest ecosystems in Greece. Being a Mediterranean country, Greece has been affected by fires of increasing intensity and frequency in recent years; (2) Methods: Information was extracted from 56 articles published in the period January 1997–March 2024 that were selected after an extensive literature review; (3) Results: An increasing trend in the number of published articles over time was observed. Studies on regulating and maintenance services prevailed. The majority of studies reported on thermo-Mediterranean ecosystems, with Pinus halepensis Mill forests being the most common ecosystems affected by fires. The effects of fire were primarily negative on provisioning and cultural services, as well as on the control of erosion rates, regulation of the hydrologic cycle, atmospheric composition, and climate regulation. Most effects on plant diversity were found to be positive, while positive and neutral effects were also recorded for pollination. The most pronounced negative or positive effects were noted for the first two years after the fire. The spatial mapping of the results showed that the areas most affected by the fires in Greece are Eastern Attica, Euboea, Western Attica, and most regional units of the Peloponnese; (4) Conclusions: In the era of climate change and changing fire regimes in the Mediterranean, there is a need to further research the impact of fire on ecosystem services, as this will help in the better protection and management of the most vulnerable forest ecosystems. Full article

Rhyzopertha dominica and Tribolium castaneum are two significant insect pests that affect the quality, quantity, and commercial value of stored products. The aim of this study was to assess the chemical composition, repellency, and insecticidal activity of Pinus halepensis leaf EO on adults of Rhyzopertha dominica (Fabricius) (Coleoptera: Bostrichidae) and Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae). The EO of P. halepensis Mill. was extracted using hydrodistillation and analyzed for its chemical composition by GC-MS. The major components identified were 1-nonadecene (25.51%), 1-hexadecene (20.79%), pimaric acid (16.71%), and palmitic acid (12.47%). The repellency test was determined by the area-preference method. P. halepensis EO exhibited significant repellent activity against T. castaneum and R. dominica. It showed high class IV repulsion rates, reaching 63.60% against T. castaneum and 66.50% against R. dominica. The repellent effect was most potent at the highest concentration tested (16 µL/mL), achieving a 100% efficacy against T. castaneum after 4 h and after 3 h against R. dominica. The contact toxicity test was carried out by impregnating filter paper disks with increasing doses of the EO studied. P. halepensis EO was the most toxic against R. dominica (LC₅₀ = 17.11 µL/mL, LC₉₀ = 30.02 µL/mL) and T. castaneum (LC₅₀ = 20.92 µL/mL, LC₉₀ = 32.18 µL/mL) after 96 h of exposure. The ability of P. halepensis EO to repel and eliminate insects suggests that it could be used as a new treatment to prevent insect infestations of R. dominica and T. castaneum. Full article

Xylella fastidiosa (XF) is a Gram-negative bacterium responsible for severe plant diseases affecting a wide range of host plants, some of them important crops. Since 2017, only the pauca subspecies (ST80) have been identified in Ibiza. XF is naturally transmitted by xylem sap-feeding insects; among them, only Philaenus spumarius (PS) and Neophilaenus campestris Fallén (NC) have been reported as potential insect vectors for XF in Ibiza. This study aims to investigate the dissemination of XF and to propose effective control strategies. The crops and the surrounding vegetation were sampled for potential vectors. DNA from insects was extracted and amplified by three qPCR methods, allowing subspecies identification. The results confirmed the continuous presence of adults of PS and NC in Ibiza and Formentera from May to December with important populations. During the summer period, PS captures predominantly took place within the surrounding woody vegetation adjacent to the plots. The main host plant for PS was Pinus halepensis Miller in Ibiza and Juniperus phoenicea subsp. turbinata (Guss.) Nyman in Formentera. In Ibiza, off the total PS captures, 4.47% tested positive for XF. These results confirm that PS is the main vector of XF on these islands, both in terms of captures and the percentage of positive insects for XF. In Formentera, despite the presence of potential vectors and the proximity and contact with Ibiza, no XF-positive insects were found, confirming the absence of the bacterium on the island. Full article

Leaf water potential ($\psi$_leaf) is a key indicator of plant water status, but its measurement is labor-intensive and limited in spatial coverage. While remote sensing has emerged as a useful tool for estimating vegetation water status, $\psi$_leaf remains unexplored, particularly in mixed forests. Here, we use spectral indices derived from unmanned aerial vehicle-based hyperspectral imaging and machine learning algorithms to assess $\psi$_leaf in a mixed, multi-species Mediterranean forest comprised of five key woody species: Pinus halepensis, Quercus calliprinos, Cupressus sempervirens, Ceratonia siliqua, and Pistacia lentiscus. Hyperspectral images (400–1000 nm) were acquired monthly over one year, concurrent with $\psi$_leaf measurements in each species. Twelve spectral indices and thousands of normalized difference spectral index (NDSI) combinations were evaluated. Three machine learning algorithms—random forest (RF), extreme gradient boosting (XGBoost), and support vector machine (SVM)—were used to model $\psi$_leaf. We compared the machine learning model results with linear models based on spectral indices and the NDSI. SVM, using species information as a feature, performed the best with a relatively good $\psi$_leaf assessment (R² = 0.53; RMSE = 0.67 MPa; rRMSE = 28%), especially considering the small seasonal variance in $\psi$_leaf ($\pm \sigma$ = 0.8 MPa). Predictions were best for Cupressus sempervirens (R² = 0.80) and Pistacia lentiscus (R² = 0.49), which had the largest $\psi$_leaf variances ($\pm \sigma$ > 1 MPa). Aggregating data at the plot scale in a ‘general’ model markedly improved the $\psi$_leaf model (R² = 0.79, RMSE = 0.31 MPa; rRMSE = 13%), providing a promising tool for monitoring mixed forest $\psi$_leaf. The fact that a non-species-specific, ‘general’ model could predict $\psi$_leaf implies that such a model can also be used with coarser resolution satellite data. Our study demonstrates the potential of combining hyperspectral imagery with machine learning for non-invasive $\psi$_leaf estimation in mixed forests while highlighting challenges in capturing interspecies variability. Full article

The assessment of fire effects in Aleppo pine forests is crucial for guiding the recovery of burnt areas. This study presents a methodology using UAV-LiDAR data to quantify malleability and elasticity in four burnt areas (1970, 1995, 2008 and 2015) through the statistical analysis of different metrics related to height structure and diversity (Height mean, 99th percentile and Coefficient of Variation), coverage, relative shape and distribution strata (Canopy Cover, Canopy Relief Ratio and Strata Percent Coverage), and canopy complexity (Profile Area and Profile Area Change). In general terms, malleability decreases over time in forest ecosystems that have been affected by wildfires, whereas elasticity is higher than what has been determined in previous studies. However, a particular specificity has been detected from the 1995 fire, so we can assume that there are other situational factors that may be affecting ecosystem resilience. LiDAR metrics and uni-temporal sampling between burnt sectors and control aids are used to understand community resilience and to identify the different recovery stages in P. halepensis forests. Full article

(1) Background: Forest fires are widespread in Mediterranean-climate regions and are becoming very common in urban and peri-urban areas. (2) Methods: Wildfires in Attica since 1977 are mapped and types of vegetation burned are reported. (3) Results: Fires are becoming larger. During the period of study (1977–2024), 45% of the burned area was covered with Pinus halepensis forests, 1.4% with Abies cephalonica forests, and 18.5% with shrublands. A relatively high percentage of the burned area (BA) affected more than once consisted of pine forests (65%). Ten percent of the total BA lies within the boundaries of the Natura 2000 network, Europe’s most important network of protected areas, of which 38.9% was burned. At the interannual scale, the BA in Attica is negatively correlated with relative humidity, while reduced precipitation may contribute to the expansion of wildfires. (4) Conclusions: Fires are becoming larger over time, with low humidity increasing the higher fire risk. Since the changing climate is expected to create more severe and uncontrollable conditions, mitigation and adaptation measures should be planned and be introduced immediately. Full article

In recent decades, climate change has significantly influenced the frequency and intensity of wildfires across Mediterranean pine forests. The loss of forest cover can bring long-term ecological changes that impact the overall biodiversity and alter species composition. Understanding the long-term impact of wildfires requires effective and cost-efficient methods for monitoring the postfire ecosystem dynamics. Passive acoustic monitoring (PAM) has been increasingly used to monitor the biodiversity of vocal species at large spatial and temporal scales. Using acoustic indices, where the biodiversity of an area is inferred from the overall structure of the soundscape, rather than the more labor-intensive identification of individual species, has yielded mixed results, emphasizing the importance of testing their efficacy at the regional level. In this study, we examined whether widely used acoustic indicators were effective at capturing changes in the avifauna diversity in Pinus halepensis forest stands with different fire burning histories (burnt in 2001, 2009, and 2018 and unburnt for >20 years) on the Sithonia Peninsula, Greece. We recorded the soundscape of each stand using two–three sensors across 11 days of each season from March 2022 to January 2023. We calculated for each site and season the following five acoustic indices: the Acoustic Complexity Index (ACI), Acoustic Diversity Index (ADI), Acoustic Evenness Index (AEI), Normalized Difference Soundscape Index (NDSI), and Bioacoustic Index (BI). Each acoustic index was then assessed in terms of its efficacy at predicting the local avifauna diversity, as estimated via two proxies—the species richness (SR) and the Shannon Diversity Index (SDI) of vocal bird calls. Both the SR and SDI were calculated by having an expert review the species identification of calls detected within the same acoustic dataset by the BirdNET convolutional neural network algorithm. A total of 53 bird species were identified. Our analysis shows that the BI and NDSI have the highest potential for monitoring the postfire biodiversity dynamics in Mediterranean pine forests. We propose the development of regional-scale acoustic observatories at pine and other fire-prone Mediterranean habitats, which will further improve our understanding of how to make the best use of acoustic indices as a tool for rapid biodiversity assessments. Full article

Pinus species are notable in Mediterranean regions due to their ecological and economic importance. Various parts of these species are widely used in traditional medicine, especially pinecones, which are a significant source of bioactive compounds. The current study aimed to evaluate the phytochemical composition and biological properties of the aqueous extracts obtained by maceration from three Pinus petal fractions, from P. halepensis Mill., P. brutia Ten., and P. pinea L. (APW, BPW, and PPW respectively), and the core fractions of the same species (ACW, BCW, and PCW respectively). The results showed that APW demonstrated superior performance compared to other species and fractions (p ≤ 0.05), with the highest total polyphenol content (203.51 mg GAE/g DW) and the highest antioxidant potential (IC₅₀ = 13.51 µg/mL) against DPPH free radical. All extracts showed high anticancer activity against HeLa and HepG2 cancer cell lines, and low inhibition against HEK-293, a normal cell line (<15%), indicating that none of extracts have any toxicity effect. Furthermore, only APW exhibits a significant inhibition against α-glucosidase with 77.20% at 50 µg/mL. HPLC-DAD analysis was conducted to identify 14 compounds. GC-MS analysis was conducted to identify 28 compounds, of which 11 were detected for the first time in this species. This study offers valuable insights into phytochemistry and potential therapeutic applications of pinecones. Full article

Retsina, Greece’s most renowned traditional wine, has been produced for millennia, with archaeological and historical evidence supporting its legacy. It is legally defined as wine made exclusively in Greece using grape must infused with Aleppo pine resin (Pinus halepensis). This study examines the effects of varying resin concentrations (0.5 g/L and 1 g/L), two commercial yeast strains, and medium-toast oak (Nadalié Cooperage, Ludon-Médoc, France) American and French, on Retsina’s chemical and sensory properties to optimise its production. Wine samples from the Savatiano grape variety were analysed for classical wine parameters, oxidation stability, volatile compounds, organic acids, phenolic profiles, and sensory attributes. Principal Component Analysis (PCA) revealed that yeast strain selection significantly influences chemical composition, with Zymaflore X5 associated with higher organic acid levels. Oak addition altered phenolic profiles, with American oak increasing ellagic acid, while non-oaked wines showed higher syringic and p-coumaric acids. Resin addition elevated alpha-pinene, a key marker of resin aroma, but reduced esters linked to fruity and floral notes. These findings highlight the complex interactions between resin, yeast, and oak, offering insights for enhancing Retsina’s quality while preserving its traditional character. Full article

Background/Objectives: The emergence of antimicrobial resistance has urged researchers to explore new antimicrobial agents, such as essential oils (EOs). The aim of this study was to examine chemical composition and antimicrobial activity of the EOs from the needles and green cones of four Pinus species (Pinus mugo Turra., P. nigra J.F., P. syilvestris L., and P. halepensis Miller) from Bosnia and Herzegovina. Methods: Chemical profiles of EOs were assessed by gas chromatography, while microdilution method was used to test their antimicrobial activity. A synergistic action of EOs and gentamicin was investigated by the checkerboard assay. Results: The chemical composition of the tested EOs showed a high percentage of α-pinene, (E)-caryophyllene, limonene, germacrene D, myrcene, and δ-3-carene. EO from green cones of P. sylvestris showed high efficiency against S. aureus and E. faecalis. The MIC of P. nigra cones’ EO was 100 μg/mL against E. coli. The EO of P. halepensis green cones demonstrated the strongest activity against E. faecalis. EOs of P. halepensis needles and green cones exhibited the highest activity against C. albicans. Further, synergistic interaction was detected in combination of the selected EOs/gentamicin toward S. aureus and K. pneumoniae. Conclusions: Among the tested EOs, oils of P. sylvestris cones and P. halepensis cones and needles showed the greatest antimicrobial activity. The same EOs and EO from P. nigra cones displayed synergistic potential in combination with gentamicin, supporting their utilization as antimicrobial agents alone or in combination with antibiotics, which is in line with their ethnopharmacological usage and circular bioeconomy principles. Full article

Climate change influences carbon sequestration by forests, either positively or negatively. In the Mediterranean region, this effect is predominantly negative, although it seems to be compensated by the elevation. This study aims to analyse the impact of climate change on carbon sequestration in five pine species—Pinus halepensis, P. nigra, P. pinaster, P. pinea, and P. sylvestris—growing across an altitudinal gradient from 573 to 1743 m a.s.l. in central Spain. Data from 300 forest inventory plots in ten forests were used to first calculate carbon sequestration in 2024. To estimate future carbon sequestration, the expected values of precipitation and temperature for 2100 were determined, based on regionalised climate scenarios for RCP4.5 and RCP8.5. Values from 13 meteorological stations located around the forests, at different elevations, were analysed, conducting a statistical analysis to determine whether variations were significant. A statistically significant variation was detected for temperature and precipitation changes only under the RCP8.5 scenario. Using temperature and precipitation data for 2024 and 2100, net potential productivity in both years was established, considering its variation ratio equivalent as equivalent to that of growth and carbon sequestration. An inflection point was detected in 2100 at 1646 m a.s.l., with a decrease in productivity below and an increase above that elevation. Results reflect a decline in carbon sequestration in all the species, ranging from 6% in P. sylvestris to 28% in P. halepensis, conditioned by the elevation. Regionally, the average decrease would be 16.4%. In temperate and boreal regions, forest growth is expected to increase due to climate change, but the Mediterranean region will experience a significant decrease, except in mountain areas. To maintain current levels of carbon sequestration, it would be necessary to increase the existing carbon sinks through new plantations and the restoration of degraded forests. Full article