Search Results (94)

Post-transplant shock is a key barrier to seedling establishment in Mediterranean-type ecosystems, especially when plant species are selected without consideration of functional traits conferring drought resistance. In this study, we investigated the responses to soil water restriction after the planting of six native sclerophyllous species, with growth form and leaf habit of evergreen trees (Lithraea caustica, Quillaja saponaria, Escallonia pulverulenta, Peumus boldus), semideciduous (Colliguaya odorifera), and deciduous shrubs (Vachellia caven), in a Mediterranean-type climate site in Central Chile. Seedlings were outplanted with tree shelters on a fire-disturbed site and subjected to two contrasting watering regimes during summer (2 L⁻¹ week⁻¹ seedling⁻¹ for 5 months versus no watering). We assessed growth, survival, gas exchange, and midday water potential one season after planting. Species differed markedly in their drought response strategies. Deciduous shrubs such as V. caven maintained high stomatal conductance and photosynthesis despite the relatively high water potential, whereas evergreen trees sustained lower water potential through pronounced stomatal closure. The highest survival (>80%) and height increments were observed in V. caven, Q. saponaria, and C. odorifera. In contrast, E. pulverulenta exhibited positive increments in height but medium survival (63%), whereas P. boldus exhibited the poorest survival (33%), indicative of low capacity to survive and successfully establish after dry summers in Mediterranean-type climates. The different strategies of the species to cope with the post-transplant shock and the harsh conditions of the planting site may guide the selection of appropriate species to guarantee the successful seedling establishment and to support the future restoration of degraded sites characterized by long periods of drought. Full article

Wildfire and atmospheric nitrogen (N) deposition are increasingly important drivers of forest recovery under global change, yet their combined effects on understory shrub dynamics remain poorly understood in subtropical forests. We quantified temporal changes in shrub aboveground biomass (AGB) following low-severity fire and N addition in a subtropical conifer–broadleaf mixed forest in Central China, and evaluated the underlying mechanisms of resource and trait. Burning reduced shrub AGB by 58.3% in the first post-fire year, but this negative effect rapidly weakened, disappeared within two years, and shifted to a net positive effect (+28.2%) by year four. Nitrogen addition increased shrub AGB by 26.5%, with gradually strengthening effects over time. Understory light availability, soil available N, and community-weighted leaf area were the key predictors explaining variation in shrub AGB. Fire induced changes in shrub AGB was most strongly associated with leaf area rather than specific leaf area or foliar nutrient concentrations. Nitrogen addition improved shrub growth primarily through increased soil N availability and foliar N enrichment. Overall, post-fire shrub recovery was governed by a successional shift in limiting factors, transitioning from initial disturbance constraint to light-driven structural control with increasing importance of soil nutrient supply. These findings demonstrate that post-fire shrub recovery in subtropical forests is increasingly governed by canopy-mediated structural strategies rather than acquisitive leaf economics during succession. Therefore, increasing wildfire activity and atmospheric N deposition may reinforce shrub-dominated understory states, with important implications for post-fire regeneration trajectories and long-term forest carbon dynamics. Full article

New Zealand species have evolved with infrequent fires, the flora being described as non-fire-adapted. Until recently, there has been contradictory information in the literature regarding the response of New Zealand indigenous species to fire, and little quantitative information on the resistance expressed in post-fire resprouting of New Zealand species. Following a grass fire at a site that had been planted, we measured the resprouting ability of a range of native species frequently used in revegetation. Resprouting was exhibited in many of the trees and shrubs, adding to the list of plants that show this fire resistance trait. Resprouting was unexpected given that bark provides resistance to fire and develops with age, and the plants were less than seven years old. Areas of regenerating native vegetation subjected to wildfire in New Zealand are frequently invaded by highly flammable, non-native species. Their presence contributes to what has been termed a fire trap, in which succession to old-growth native forest (and other habitats) is repeatedly reset. We discuss the potential of green firebreaks to escape this trap and conclude that such an escape will require active management. Full article

Fire plays a central role in shaping regeneration dynamics in Pinus canariensis C. Sm. & DC. forests, yet the relative importance of different fire-related cues and post-fire environmental filters remains poorly understood. We experimentally evaluated the effects of drought, heat, smoke, ash and soil microbial extracts on the germination of seven co-occurring species representing the main functional groups of these forests. Germination responses varied markedly among species, revealing that no single cue dominates early recruitment. Drought emerged as the strongest and most consistent filter, sharply reducing germination success and slowing emergence in P. canariensis and Fabaceae, while Poaceae remained largely insensitive under the imposed water potentials. Ash enhanced germination in P. canariensis and Cynosurus echinatus L., indicating that nutrient-rich post-fire substrates can facilitate emergence when moisture is available. Soil and microbial extracts accelerated germination in fast-emerging grasses, providing the first experimental evidence that post-fire soil legacies influence recruitment in Macaronesian pine forests. In contrast, heat acted as a species-specific cue, with only limited stimulation at moderate temperatures and widespread declines under extreme heat, while the smoke treatment used in this study produced negligible effects across all species. Across treatments, germination timing emerged as a key functional axis, structuring regeneration niches, with rapid-germinating Poaceae favoured under increasing aridity. Our findings highlight the dominant role of hydric stress, the selective relevance of ash and soil legacies, and the functional divergence among species, offering new mechanistic insights into post-fire regeneration under current and future climate scenarios. Full article

Federated learning enables privacy-preserving training of spiking neural networks on distributed neuromorphic and event-based data, but it also exposes the global model to stealthy backdoor attacks injected by malicious clients. Compared with conventional artificial neural networks, federated spiking neural networks are more difficult to sanitize because malicious behavior may be encoded not only in spatial filters but also in spike timing, membrane dynamics, and temporal firing sparsity. Existing backdoor defenses usually require repeated federated retraining, access to client data, trigger synthesis, or computationally expensive model repair, which limits their practicality in low-power neuromorphic deployment. This paper proposes FedTSR, a fast post-training backdoor removal framework for spiking neural networks trained through federated learning. FedTSR introduces two coordinated algorithms: temporal synaptic risk estimation, which identifies backdoor-sensitive synaptic groups by measuring abnormal spike-response contributions across simulation timesteps using a small clean calibration set, and spike-consistency recalibration, which restores benign task performance through lightweight membrane-potential alignment and firing-rate regularization without restarting federated training. The proposed method is trigger-agnostic, client-independent, and compatible with surrogate-gradient trained spiking models. Here, trigger-agnostic means that FedTSR does not use trigger identity during repair; it should not be interpreted as certified robustness against every adaptive trigger family. Experiments on real neuromorphic and vision benchmarks, including N-MNIST, CIFAR10-DVS, DVS Gesture, and CIFAR-10, show that FedTSR substantially reduces attack success rate while preserving clean accuracy under multiple backdoor patterns, poisoning ratios, and non-IID federated settings. The results indicate that exploiting temporal spike dynamics provides an efficient and effective route for sanitizing compromised federated spiking neural networks. Full article

Conventional structural design frameworks assess natural hazards as statistically independent phenomena, a practice that can lead to significant underestimation of risk for structures subjected to sequential or concurrent hazards. The generation of probabilistic fragility functions under such cascading loads, particularly for post-fire seismic events, presents a computational barrier for standard non-linear dynamic analysis. To address this barrier, this study introduces a comprehensive computational framework centered on a physics-constrained neural network (PCNN) to serve as a high-fidelity surrogate model. The framework first uses a non-linear 12-degree-of-freedom structural model to generate a baseline dataset of collapse times under post-fire, concurrent wind-earthquake loading via the computationally efficient endurance time (ET) method, confirming that wind effects are negligible under ambient conditions and that the framework correctly identifies this hazard hierarchy without prior labeling, while fire and seismic parameters dominate. This dataset is subsequently used to train the PCNN, which is validated to achieve exceptional predictive accuracy ($R^2=$ 0.991), performing on par with a state-of-the-art Random Forest model while enforcing physical constraints. A feature importance analysis confirmed that structural collapse is dominated by fire intensity (≈55%) and initial structural period (≈45%). The validated PCNN is then applied to demonstrate the framework’s capability, rapidly generating fragility curves that quantify the catastrophic effect of fire on seismic resilience. This analysis reveals that a severe 800 °C localized fire reduces the structure’s median collapse capacity by 94.7%, thereby establishing the proposed framework as a successful template for tackling complex, non-linear problems in multi-hazard engineering. Full article

Fires are an ecological force that often mediates the balance between native and exotic plants in communities. We monitored post-fire vegetation dynamics in a Pinus pinaster plantation and adjacent grasslands 9, 15, and 18 months after the fire, evaluating structural and compositional changes through multivariate analyses. The invasive alien Acacia longifolia cover increased significantly in the plantation (p = 0.0006), while pine needle cover declined significantly (p = 0.0027), and P. pinaster cover did not change significantly over time (p = 0.063), although it showed an increasing trend towards the late stage. Both A. longifolia and pine needles were negatively associated with native species cover. Native cover remained consistently higher in continuous grasslands, with a significant Time × Site interaction. Post-fire succession in the plantation was associated with sequential abiotic and biotic filters, and the increase in A. longifolia may have contributed to reduced native recovery through competitive effects. These results suggest that fire alone may be insufficient to restore native grassland conditions within afforested systems and that early post-fire control of A. longifolia may be necessary to redirect succession. Full article

Forest fires are a major concern due to their significant impact on the environment, economy, and wildlife habitats. Efficient early detection systems can significantly mitigate their devastating effects. This paper provides a comprehensive review of forest fire detection (FFD) techniques and traces their evolution from basic lookout-based methods to sophisticated remote sensing technologies, including recent Internet of Things (IoT)- and Unmanned Aerial Vehicle (UAV)-based sensor network systems. Historical methods, characterized primarily by human surveillance and basic electronic sensors, laid the foundation for modern techniques. Recently, there has been a noticeable shift toward ground-based sensors, automated camera systems, aerial surveillance using drones and aircraft, and satellite imaging. Moreover, the rise of Artificial Intelligence (AI), Machine Learning (ML), and the IoT introduces a new era of advanced detection capabilities. These detection systems are being actively deployed in wildfire-prone regions, where early alerts have proven critical in minimizing damage and aiding rapid response. All FFD techniques follow a common path of data collection, pre-processing, data compression, transmission, and post-processing. Providing sufficient power to complete these tasks is also an important area of research. Recent research focuses on image compression techniques, data transmission, the application of ML and AI at edge nodes and servers, and the minimization of energy consumption, among other emerging directions. However, to build a sustainable FFD model, proper sensor deployment is essential. Sensors can be either fixed at specific geographic locations or attached to UAVs. In some cases, a combination of fixed and UAV-mounted sensors may be used. Careful planning of sensor deployment is essential for the success of the model. Moreover, ensuring adequate energy supply for both ground-based and UAV-based sensors is important. Replacing sensor batteries or recharging UAVs in remote areas is highly challenging, particularly in the absence of an operator. Hence, future FFD systems must prioritize not only detection accuracy but also long-term energy autonomy and strategic sensor placement. Integrating renewable energy sources, optimizing data processing, and ensuring minimal human intervention will be key to developing truly sustainable and scalable solutions. This review aims to guide researchers and developers in designing next-generation FFD systems aligned with practical field demands and environmental resilience. Full article

Wildfires represent one of the most destructive natural disturbances, yet they play a fundamental ecological role in the regeneration and evolution of forest ecosystems. In Mediterranean regions, fire acts as a selective factor shaping plant adaptive strategies and the structure of vegetation mosaics. This study analyzes post-fire regeneration dynamics in Pinus radiata and P. pinaster plantations located in Roccaforte del Greco (Metropolitan City of Reggio Calabria, southern Italy), severely affected by the 2021 wildfires. Phytosociological surveys were conducted along permanent transects using the Braun-Blanquet method and analyzed through diversity indices (Shannon, Evenness), Non-Metric Multidimensional Scaling (NMDS), Indicator Species Analysis (IndVal), and hierarchical clustering. The results reveal a clear floristic differentiation among management conditions, with higher species diversity and variability, and a predominance of pioneer therophytes and hemicryptophytes in burned areas. The in situ retention of burned logs enhances structural and microenvironmental heterogeneity, facilitating the establishment of native species and supporting post-fire functional recovery. Overall, this preliminary study, focusing on early successional dynamics, suggests that the in situ retention of burned logs may positively contribute to ecosystem resilience and biodiversity in post-fire Mediterranean pine forests, while also highlighting the need for long-term monitoring to confirm the persistence of these effects. Full article

Wildfires are increasing globally and pose major challenges for assessing post-fire vegetation recovery and ecosystem resilience. We analyzed long-term Landsat time series in two contrasting fire-prone ecosystems in the United States and Australia. Vegetation area was extracted using the Enhanced Vegetation Index (EVI) with Otsu thresholding. Recovery to pre-fire baseline levels was modeled using linear, logistic, locally estimated scatterplot smoothing (LOESS), and generalized additive models (GAM), and their performance was compared using multiple metrics. The results indicated rapid recovery of Australian forests to baseline levels, whereas this was not the case for forests in the United States. Among climatic factors, temperature was the dominant parameter in Australia (Spearman ρ = 0.513, p < 10⁻⁸), while no climatic variable significantly influenced recovery in California. Methodologically, GAM consistently performed best in both regions due to its success in capturing multiphase and heterogeneous recovery patterns, yielding the lowest values of AIC (United States: 142.89; Australia: 46.70) and RMSE_cv (United States: 112.86; Australia: 2.26). Linear and logistic models failed to capture complex recovery dynamics, whereas LOESS was highly sensitive to noise and unstable for long-term prediction. These findings indicate that post-fire recovery is inherently nonlinear and ecosystem-specific and that simple models are insufficient for accurate estimation, with GAM emerging as an appropriate method for assessing vegetation recovery using remote sensing data. This study provides a transferable approach using remote sensing and GAM to monitor forest resilience under accelerating global fire regimes. Full article

Reliable geolocation of thermal hotspots, such as smoldering embers that can reignite after vegetation fire suppression, deep-seated peat fires, or underground coal seam fires, is critical to prevent fire resurgence, limit prolonged greenhouse gas emissions, and mitigate environmental and health impacts. This study develops and tests an algorithm to estimate the GPS positions of thermal hotspots detected in infrared images acquired by an unmanned aerial vehicle (UAV), designed to operate over flat and mountainous terrain. Its originality lies in a reformulated Bresenham traversal of the digital elevation model (DEM), combined with a lightweight, ray-tracing-inspired strategy that efficiently detects the intersection of the optical ray with the terrain by approximating the ray altitude at the cell level. UAV flight experiments in complex terrain were conducted, with thermal image acquisitions performed at 60 m and 120 m above ground level and simulated hotspots generated using controlled heat sources. The tests were carried out with two thermal cameras: a Zenmuse H20T mounted on a Matrice 300 UAV flown both with and without Real-Time Kinematic (RTK) positioning, and a Matrice 30T UAV without RTK. The implementation supports both real-time and post-processed operation modes. The results demonstrated robust and reliable geolocation performance, with mean positional errors consistently below 4.2 m for all the terrain configurations tested. A successful real-time operation in the test confirmed the suitability of the algorithm for time-critical intervention scenarios. Since July 2024, the post-processed version of the method has been in operational use by the Corsica fire services. Full article

We present a site-agnostic workflow to identify Fireline Tactical Support Points (FTSPs) and corridors following wildfire where spectral-change proxies (dNBR, RdNBR, and dNDVI) are paired pre/post-fire and co-registered on a 20 m grid together with a 72 h rainfall accumulation layer, which is treated as an operational feasibility and safety overlay, complementing access and terrain. Applied to the Vesuvius National Park (Italy) wildfire episode of August 2025, the pipeline yields suitability/susceptibility surfaces, ranked factors, and corridor candidates, with estimated successes including coherent prioritization within high-severity mosaics, improved continuity toward existing access routes, and reduced overlap with mapped sensitive areas at like-for-like suitability. Low-carbon staging is retained as a design safeguard, while detailed greenhouse-gas accounting is intentionally deferred to future, fleet-resolved multi-criteria analyses. The approach enables rapid, repeatable decision support and is relevant to SDG 11 (Sustainable Cities and Communities), SDG 13 (Climate Action), and SDG 15 (Life on Land). Full article

The Ōbaku Edition of the Buddhist Canon, initiated and spearheaded by Tetsugen Dōkō (鐵眼道光 1630–1682), profoundly influenced Japanese Buddhism and printing culture. Although the Ōbaku Edition has long been recognized as a product of cross-border collaboration, earlier studies have primarily focused on its textual features and religious significance after publication. As a result, the specific mechanisms and significance of its transnational nature have remained underexplored. This study revisits the canon’s compilation as a complex trans-sectarian and transnational social practice. Drawing on a variety of sources, it provides new insights into the production of the Ōbaku Canon, showing that this trans-sectarian project was driven by the interplay of several key dynamics: transnational networks supplying its base text, intellectual contributions from Chinese migrants, local social needs in post-fire Nagasaki, and Tetsugen’s personal aim to use the canon in doctrinal debate. Tetsugen’s printing endeavor continued the medieval tradition of kanjin (fundraising), serving as a religious, educational, and institutional undertaking shaped by interactions with broader socio-economic support. Positioned within a wider social framework, Tetsugen’s cross-sectarian activities facilitated the successful circulation and popularization of the canon, promoting a shift in the use of Buddhist scriptures from prayer-centered practice to doctrinal study and reflecting a broader transformation in Japanese Buddhism, from state-supported Buddhism to more popular forms. 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

Human activities are increasing the occurrence of megafires that alter ecological dynamics in forest ecosystems. The objective of this study was to understand the impacts of a 610 km² megafire on patterns of tree regeneration and herbivory across three forest types (aspen/fir, oak/maple, and pinyon/juniper). Seventeen transect pairs in adjacent burned/unburned forest stands (6 aspen/fir, 5 oak/maple, and 6 pinyon/juniper) were measured. Sapling density, meristem removal, and height were measured across the transect network over a three-year period from 2019 to 2021. Tree species able to resprout from surviving roots (oak and aspen) generally responded positively to fire while species that typically regenerate by seeding showed little post-fire regeneration. Browse pressure was concentrated on deciduous tree species and was greater in burned areas but the effect diminished over the three-year study period. Meristem removal by herbivores was below the critical threshold, resulting in vertical growth over time. Our results indicate that forest regeneration within the megafire scar was generally positive and experienced sustainable levels of ungulate browsing that were likely to result in forest recruitment success. Full article