Search Results (2,063)

Clonostachys rosea, an entomopathogenic fungus that infects Cephalcia chuxiongica, is highly pathogenic and has significant potential for controlling the damage this pest causes to pine forests. To investigate the role of C. rosea secondary metabolites in fungal pathogenicity, we conducted toxicity assays using crude metabolite extracts. These assays evaluated the effects of different concentrations, larval developmental stages, and exposure methods on larval mortality. Gas chromatography–mass spectrometry (GC–MS) was subsequently employed to identify the chemical constituents of the crude extracts, and the toxicity of the identified compounds was assessed. The results showed that the crude extract at a concentration of 7.5 μg/mL exhibited the highest toxicity. Two hours post-treatment, the mortality rate of non-diapause larvae reached 65%, which was significantly higher than that of the diapause group. Moreover, contact toxicity was more lethal to C. chuxiongica larvae than oral exposure. A total of 23 compounds were identified from the crude extract, of which nine exhibited toxicity: 2-piperidone, hydrocinnamic acid, phenethyl alcohol, oleic acid, tryptophol, stearic acid methyl ester, myristic acid, dodecanoic acid, and benzeneacetic acid. Except for 2-piperidone, which showed low toxicity, the other eight compounds demonstrated notable contact toxicity against C. chuxiongica larvae. These findings confirm the insecticidal potential of C. rosea secondary metabolites and provide a valuable reference for the biological control of C. chuxiongica and other chewing insect pests. Full article

This study investigated the distribution of pine wood nematodes (PWNs, Bursaphelenchus xylophilus) and their co-occurrence with B. mucronatus in recently dead pine trees across coastal and inland regions while monitoring the seasonal emergence patterns of Monochamus alternatus from 2021 to 2023. Nematodes were extracted from felled trees and beetle bodies using the Baermann funnel method. Aggregation pheromone traps were used to monitor vector activity and to assess temperature-dependent emergence. The results showed a negative correlation between PWN and B. mucronatus density (r = −0.73, p < 0.01), which prompted tests on interspecific interactions. M. alternatus emergence was positively associated with average temperature (r = 0.74–0.78), supporting the temperature-informed surveillance timing in this dataset. These findings highlight the role of climate-driven dynamics in shaping vector behavior and nematode population structures. This study supports the development of sustainable temperature-responsive management strategies for controlling pine wilt disease. These strategies provide a foundation for climate-resilient forest health and long-term ecosystem sustainability. Full article

Norway spruce (Picea abies (L.) H. Karst.) is a primary forest-forming species in the European part of Russia, both in terms of its distribution and economic importance. A number of studies indicate that one of the reasons for the disturbance of spruce forests is linked to rising temperatures, particularly the detrimental effects of extreme droughts. The aim of our research is to identify changes in the structural and functional organization of mature spruce forests at the center of the East European Plain. The study was conducted in intact spruce forests using resurveyed vegetation relevés within the Smolensk–Moscow Upland, with relevés repeated after 40 years (in 1985 and 2025). Changes in structural and functional parameters of spruce communities were analyzed. The results showed that significant disturbances of the tree layer led to changes in the vegetation of subordinate layers, as well as the successional dynamics of spruce forests. It was found that following the collapse of old-growth spruce stands, two types of secondary succession developed: (1) with the renewal of spruce and (2) with active development of shrubs (hazel and rowan) and undergrowth of broadleaved species. It was also demonstrated that the typological diversity of the studied communities changed over 40 years not only due to the loss of the tree layer and the formation of new “non-forest” types but also because several mixed spruce-broadleaved communities transitioned into broadleaved ones, and pine–spruce communities of boreal origin shifted to nemoral types. An analysis of the complete species composition of spruce forests based on Ellenberg’s scales scoring revealed changes in habitat conditions over the 40-year period. A noticeable trend was an increase in the proportion of thermophilic and alkaliphilic species, indicating a shift toward a nemoral vegetation spectrum. It is expected that under the current forest management regime, the next 40 to 60 years will see a decline in the proportion of spruce within mixed stands, potentially culminating in the complete collapse of monospecific spruce forests in the center of the East European Plain. Full article

This study investigates the spatial heterogeneity and species diversity of grassland vegetation in the agro-pastoral ecotone of China’s Loess Plateau, integrating Taylor’s power law model with the minimum area concept to address scale-dependent ecological patterns. Field surveys were conducted across four vegetation types: small-leaf poplar forest (SP), pine–caragana mixed forest (PC), caragana shrubland (RC), and saline grassland (SG). Nested quadrats (0.25–8 m²) were used to establish species–area relationships (SARs), while binary occurrence frequency data fitted to Taylor’s power law quantified spatial heterogeneity parameters (δ_i, δ_c, CACD) and derived diversity indices (H′, J′, D). the results showed that species composition differed significantly among vegetation types, with RC exhibiting the highest richness (25 species) and SG the lowest (12 species). SAR analysis showed distinct z-values: SP had the lowest z (0.14), indicating minimal area effects and high homogeneity, while SG had the highest area sensitivity. Spatial heterogeneity (δ_c) was highest in RC and lowest in SP. Over 82.5% of herb-layer species exhibited aggregated distributions (δ_i > 0). The dominant species Leymus secalinus (Georgi) Tzvelev shifted from regular (δ_i < 0) under SP/SG to aggregated (δ_i > 0) under PC/RC. Diversity metrics peaked in PC plots (highest H′ and richness, lowest dominance), whereas SP showed high dominance but low diversity. CACD values (critical aggregation diversity) were maximized under SG. The integration of power law modeling and minimum area analysis effectively captures scale-dependent vegetation patterns. Pine–caragana mixed forests (PC) optimize biodiversity and spatial heterogeneity, suggesting moderated canopy structures enhance ecological stability. These findings provide a theoretical basis for sustainable grassland management in ecologically sensitive agro-pastoral zones. Full article

Soil microbial communities are important for nutrient cycling regulation in forest ecosystems. However, limited knowledge exists regarding the characteristics of these microbial communities in Masson pine (Pinus massoniana Lamb.) plantations of different stand ages. In this study, four planted Masson pine stands (8-year-old, 12-year-old, 22-year-old, and 38-year-old stands) and one natural broadleaved forest stand (as a control) with three replications, were selected in the Laoshan Forest Farm, Qiandao Lake Town, Zhejiang Province, China. Soil physicochemical properties were measured and their effects on soil microbial communities were studied. Amplicon-based high-throughput sequencing was employed to process raw sequence data for soil microbes. It is worth noting that significant differences (p < 0.05) in soil bacterial genera were observed among different stand age groups. Total nitrogen (TN), total phosphorus (TP), total potassium (TK), available potassium (AK), soil organic carbon (SOC), and soil bulk density (BD) were identified as the primary factors influencing bacterial community distribution (p < 0.05). Available nitrogen (AN), SOC, TN, and TK showed significant correlations with soil fungal communities (p < 0.05). These findings underscore the crucial role of soil physicochemical properties in shaping soil microbial community composition in Masson pine plantations. Full article

Pine wilt disease (PWD), transmitted by Monochamus alternatus (JPS), poses a severe threat to global pine forests. Although the entomopathogenic fungi Beauveria bassiana (Bb) and Metarhizium anisopliae (Ma) represent environmentally friendly biocontrol alternatives, their practical application is limited by inconsistent field performance and an incomplete understanding of host–pathogen interactions. We employed dual RNA-seq at the critical 48 h infection time point to systematically compare the transcriptional responses between JPS and Bb/Ma during infection. Key findings revealed distinct infection strategies: Bb preferentially induced autophagy pathways and modulated host carbohydrate metabolism to facilitate nutrient acquisition, triggering corresponding tissue degradation responses in JPS. In contrast, Ma primarily co-opted host amino acid and sugar metabolic pathways for biosynthetic processes, eliciting a stronger immune defense activation in JPS. Notably, the mTOR signaling pathway was identified as a key regulator of the differential host responses to various entomopathogenic fungi. Further functional validation-specifically, the application of a chemical inhibitor and RNAi targeting mTOR in JPS-confirmed that mTOR inhibition selectively enhanced Bb-induced mortality in JPS without affecting Ma virulence. Our findings reveal the molecular determinants of host–pathogen specificity in PWD biological control and indicate that mTOR regulation could serve as an effective strategy to improve fungal pesticide performance. Full article

The “divergence problem” in recent decades is a tendency for trees in high latitudes to lose climate sensitivity. Growth divergence has been reported for certain tree species in alpine or northern latitude locations but has yet to be found in species with southern distributions. This retrospective study used tree ring data collected from longleaf pine trees (Pinus palustris Mill.) in natural stands and a young plantation to test whether divergence exists in this important southeastern tree species. Our results demonstrate that a growth divergence in basal area increment (BAI) occurred among individual longleaf pines within stands. The BAI of each tree followed Taylor’s law but with differing exponents, which varied from 0.75 to 6.4. Divergence of BAI among trees increased with time, and it might be related to the local drought, as the highest BAI divergence occurred when the SPEI (standardized precipitation-evapotranspiration index) was approximately 0 (−0.3–0.3). Hourly dendrometer measurements confirmed growth divergence among individuals. Collectively, our study provides new information about the growth characteristics of longleaf pine, which may partially explain how this species persists and thrives in southeastern environments. Our current management strategy on longleaf pine forests, such as prescribed burning and genetics improvement efforts, needs to be adapted. Full article

A sharp escalation in wildfire frequency, severity, and scale in the western United States calls for the creation of forests that are resilient in the future. One reforestation method involves clustering trees into groups of two to four, instead of creating evenly spaced plantations, in an effort to increase structural heterogeneity and emulate natural regeneration patterns. There have been a limited number of studies on clustered plantations, and this study addresses this important research gap. In Eldorado National Forest in the Sierra Nevada, we compared growth and structure in several post-fire plantations, treated with and without pre-commercial thinning (PCT), and naturally regenerating stands. Using mixed-effects models, we tested for growth and structural differences between evenly spaced and clustered plantations, as well as comparing them to stands of naturally regenerating trees. Our results indicated that diameter and height growth were generally better maintained in the plantations compared to under natural stand conditions. When considering plantation arrangement, the annual basal area increment (BAI) thinning index ([BAI after thinning − BAI before thinning]/BAI before thinning) was generally higher in evenly spaced plantations (1.03) compared to clustered plantations (0.79). While high plant diversity would be important eventually from an ecological perspective, our study suggests that during the initial phases of plantation development, lower shrub diversity could assist with plantation establishment and growth. The frequency of yellow pines was an important, positively associated factor affecting BAI and height growth, but primarily in the high-elevation region, which demonstrates a facilitative legacy effect of prior stand composition. Our study highlighted the important legacy effect of prior stand density on the growth of yellow pines, but primarily in the low-elevation region, and only when the two plantation groups were examined. The negative association suggests that a lower initial density of plantations promotes better BAI growth and height growth after PCT. These findings thus have broad implications for effective post-fire restoration of young plantations to help ensure their future resilience to both post-fire restoration and climate change adaptation and biotic (i.e., plant competition) stress factors. Full article

The invasive sap-feeding pest Toumeyella parvicornis (pine tortoise scale) is rapidly spreading across Europe, threatening pine ecosystems, particularly in forest–urban areas of Italy. In this scenario, early detection and monitoring strategies are critical to prevent new outbreaks and mitigate impacts in infested regions. Current surveillance is challenged by the lack of rapid, sensitive tools for indirect detection of this cryptic, canopy-dwelling pest, despite advancements in molecular diagnostics and environmental DNA (eDNA). Here, we established a highly specific qPCR assay using LNA probe chemistry for detecting T. parvicornis DNA from both adult insects and their excreted honeydew. DNA was successfully isolated/quantified from all tested matrices. We recorded average Cq values of 20.9 for insect specimens and 30.3 for collected honeydew samples. Targeting the COI barcoding region, the assay demonstrated excellent specificity in both in silico and in vitro tests, showing no cross-reactivity to other pine-associated taxa. The limit of detection for DNA isolated from insect was 64 fg/µL. This is the first diagnostic protocol to use honeydew as a matrix for indirect detection of T. parvicornis. Optimized for routine application by Plant Health Services, this eDNA-based tool offers a valuable approach for future monitoring of sap-sucking hemipterans in multiple environments. Full article

The strategic importance of forest biomass as a renewable energy source is growing across the EU, driven by climate goals, energy security, and the abundance of logging residues. While logging waste offers considerable potential for bioenergy production, its life cycle environmental impacts remain insufficiently understood. This study evaluates the impacts of utilizing Scots pine (Pinus sylvestris) logging residues for energy production in Lithuania using a comparative life cycle assessment (LCA). Two harvesting scenarios were assessed at midpoint and endpoint levels: one excluding and one including logging residues. The results show that about 173.2 tons of biofuels can be produced from one hectare of Scots pine forest over a 100-year cycle, generating up to 513.6 MWh of energy when residues are utilized. The LCA revealed improvements in 9 of 18 impact categories, with greenhouse gas avoidance increasing from –52 to –89.5 t CO₂ eq, and overall endpoint impacts decreasing by nearly 39%. The novelty of this study lies in applying established LCA methods with region- and species-specific data, partly obtained through monitoring, for Scots pine residues in Lithuania, while extending system boundaries to include soil degradation, storage losses, and ash management—providing a more holistic and Northern Europe-relevant perspective. Full article

The biogenic organization of widespread valley pine ecosystems on sandy alluvium leads to an increase in soil fertility, productivity, and biodiversity through autogenic successions. Using our own stationary observations and literary data on the productivity of pine forests in Russia, Belarus, and Ukraine, we quantified the mechanism of autogenic forest successions associated with carbon sequestration and the influence of organic matter dynamics on the fertility and water retention of sandy soils. The low rate of organic matter turnover in primary succession leads to the intensive accumulation of thick (6–8 cm) forest litter and the formation of small humus-eluvial horizons with total carbon storage up to 50 Mg/ha. This soil structure retains 2–6 times more water and biophilic elements than in the original sandy alluvium. It is suitable for the settlement of more demanding broadleaf species and nemoral herbs with higher rates of litterfall, its decomposition and humification. As a result, simple pine forests on Arenosols and primitive Sod-podzolic soils are replaced by complex, more productive linden–oak–pine ecosystems on developed Cambisols with thick (up to 30 cm) humus horizons, carbon storage of 80–100 Mg/ha and higher (2–7 times compared to the previous soils) fertility and water-holding capacity. This mechanism is adequately described by a nonlinear process model with a trigger reaction of plant productivity to the storage and quality of soil organic matter, suitable for predicting long-term carbon sequestration during the succession of valley pine forests and the effectiveness of artificial afforestation. Full article

Wildfire activity is intensifying globally as climate change amplifies heat waves, droughts and wind extremes, threatening biodiversity. South Korea (63% forested) has experienced a sharp rise in large fires. We analysed 905 wildfires ≥ 5 ha from 1980–2024, linking burned area to maximum wind speed, relative humidity, temperature and forest structure (conifer, broadleaf and mature–stand ratios, forest cover). Pearson correlations, HC3-corrected regression, a 1000-tree Random Forest and five-fold validated XGBoost interpreted with SHAP captured linear and nonlinear effects; WUI influences were examined qualitatively. Each 1 m s⁻¹ increase in peak wind expanded burned area by ~8.5 ha, whereas a 1% rise in humidity reduced area by ~3 ha (p < 0.01). Broadleaf prevalence restrained spread, while high conifer and mature–stand proportions enlarged it. Machine learning raised explanatory power from R² = 0.62 to 0.66 and showed that very dry air, strong winds and conifer cover above half the landscape coincided with the largest events. Burned area during 2020–2024 reached 29,905 ha—sevenfold that of 2015–2019. These results imply that extreme fire weather, flammable pine fuels and expanding WUI settlements jointly elevate risk; implementing real-time meteorological thresholds, targeted fuel treatments and stricter WUI zoning can help mitigate this risk. Full article

Wildfires are a major ecological disturbance in Mediterranean forests, whose frequency and intensity are increasingly driven by climate change and land-use dynamics. This study investigated post-fire natural regeneration and soil properties in Aleppo pine stands seven years after a high-severity crown fire in southern Italy. Two stand types—pure pine and mixed pine—were compared, differing in fire severity and structural composition. We evaluated seedling density and dendrometric parameters (height and collar diameter), as well as soil parameters (pH, organic matter, and bulk density) to assess their role in post-fire recovery. Regeneration was abundant and composed exclusively of Aleppo pine, with significantly higher seedling density in the pure pine stand, where fire severity was greatest. In mixed pine stand, moderate fire severity combined with interspecific competition limited regeneration density. Deadwood presence enhanced microclimatic conditions favorable to seedling establishment, supporting a post-fire recovery dynamic consistent with self-succession, whereby pre-fire dominant species are favored. Soil analyses revealed higher organic matter content and lower bulk density in the pure stand, which likely facilitated regeneration. Overall, these findings underscore the ecological value of deadwood retention and passive management strategies in fostering spontaneous forest recovery. A better understanding of post-fire regeneration patterns and soil conditions can inform adaptive management approaches to strengthen forest resilience in Mediterranean forests under increasing climate pressure. Full article

Resin is a renewable non-timber forest product that is used as a raw material in a wide range of goods, thereby holding significant socioeconomic importance and relevance across multiple industrial sectors. This study aims to provide a comprehensive review of the main factors influencing natural resin production in Pinus stands, as well as to address the effects of these factors on tree growth dynamics and resin yield optimization. Among these factors, dendrometric characteristics, environmental conditions, and silvicultural practices, such as thinning, pruning, and prescribed burning, are particularly relevant. However, the scientific literature presents conflicting results regarding the influence of these factors on resin yield, as well as the impacts of resin tapping on tree growth and wood quality. These divergences highlight the complexity of the process and reinforce the need for further studies to clarify the interactions between silvicultural practices in Pinus stands and resin production. Understanding these practices is essential for the development and implementation of efficient silvicultural models aimed at optimizing resin tapping that are properly tailored to the specific conditions of each site. In this context, the development of management models that integrate both timber and resin production is fundamental for simulating management scenarios, generating yield forecasts, and supporting decision-making processes. It is worth noting that management models focused on maximizing resin production may differ from conventional approaches intended for pulpwood or sawtimber production. Nevertheless, integrating resin tapping with timber harvesting holds significant potential to increase the profitability of forest operations. Full article

Ectomycorrhizal fungi (EMF) associated with the roots of Pinus cembroides subsp. orizabensis, a key pinyon pine species for local forestry in the Oriental Basin, Puebla, Mexico, were identified and analyzed. The study aimed to evaluate the diversity of EMF in this endemic pine across three sampling transects (T1, T2, T3), each located in sites with different vegetation compositions and pine cover. In each site, a 100 m × 25 m transect was established, and root tips colonized by EMF were collected for morphological and molecular identification. Alpha (α) and beta (β) diversity were calculated for each transect. A total of 16 EMF morphotypes were identified, and molecular analysis confirmed four taxa: Geopora arenicola, Rhizopogon aff. subpurpurascens, Tomentella sp. 1, and Tricholoma sp. 1. The transect with the highest P. cembroides cover showed the greatest fungal richness. Beta diversity, as measured by Sørensen index partitioning, revealed a 30% species turnover between T1 and T2 and a 60% turnover between T2 and T3, suggesting distinct fungal communities. In contrast, no turnover but a nested pattern was observed between T1 and T3, indicating that the less diverse community is a subset of the richer one. These results show that EMF composition varies with pine cover and vegetation heterogeneity, highlighting the influence of disturbance on fungal diversity. This is the first report of EMF fungi associated with Pinus cembroides subsp. orizabensis, as well as the first record of G. arenicola in arid pine forests in Mexico. Full article