This study explored the effects of forest fires on soil microbial activity in forest soils classified by rock origin (igneous, metamorphic, and sedimentary) and stratified by subsoil depth (topsoil, subsoil). Microbial activity, indicated by average well color development (AWCD) and Shannon diversity indices, was higher in undamaged topsoils compared to fire-damaged ones. In contrast, fire-damaged subsoils, particularly in metamorphic and sedimentary soils, exhibited increased microbial activity over time due to organic matter decomposition. A significant increase in substrate utilization was observed in undamaged soils across all rock types (*p < 0.05, **p < 0.01) in topsoil, with sedimentary rock exhibiting the highest microbial diversity based on Shannon indices. The dehydrogenase activity followed a similar pattern, with reduced activity in fire-damaged topsoil but higher activity in damaged metamorphic and sedimentary subsoils. Principal component analysis (PCA) linked microbial indicators (AWCD, Shannon index) to mineral compositions like orthoclase and hornblende, highlighting the role of soil chemistry in shaping microbial responses to fire. These insights advance the understanding of fire-induced changes in soil microbial functions across diverse geological contexts.

AimHigh temperatures during forest fires can cause significant damage to tropical dry forest areas and alter their ecological stability, particularly by affecting seed viability and seedling emergence. This study evaluates the seedling emergence response of 18 dry forest species to fire-simulated temperatures, aiming to assess their potential for restoration in fire-prone Colombian ecosystems.LocationThe seeds used in this study were obtained from three tropical dry forests in Colombia.MethodsA total of 9832 seeds from 18 dry forest species were collected directly from the soil seed bank in three tropical dry forests in Colombia. These seeds were then exposed to simulated forest fire temperatures (100 degrees C, 150 degrees C, and 200 degrees C) for 10 min. Seed viability was analyzed using the 2,3,5-triphenyl tetrazolium chloride reagent (tetrazolium test) and assessed using a generalized linear model. Seedling emergence and mean emergence time were evaluated using one-way analysis of variance (ANOVA) with temperature treatments as factors.ResultsThe study revealed that seedling emergence significantly decreased with higher heat shock temperatures. Notably, Hura crepitans and Parkinsonia aculeata tolerated temperatures up to 100 degrees C, while Caesalpinia pulcherrima and Enterolobium cyclocarpum showed increased emergence at that temperature. Based on their emergence responses, species were classified as stimulated, tolerant, sensitive, or vulnerable. Seed viability declined with rising temperatures, and the mean emergence time increased in species like Cordia alba, Crescentia cujete, and Lonchocarpus violaceus.ConclusionsThis study shows that heat shocks at 150 degrees C and 200 degrees C significantly reduced seed bank viability for most Colombian dry forest species. However, Caesalpinia pulcherrima and Enterolobium cyclocarpum were stimulated by 100 degrees C heat shocks, while Hura crepitans and Parkinsonia aculeata showed no adverse effects. Vulnerable species like Coccoloba acuminata and Pithecellobium dulce exhibited no viable seeds at higher temperatures, suggesting potential local extinctions. These results emphasize the need to focus on heat-tolerant species for restoration efforts in fire-prone ecosystems.

This study analyzes the forest flammability hazard in the south of Tyumen Oblast (Western Siberia, Russia) and identifies variation patterns in fire areas depending on weather and climate characteristics in 2008-2023. Using correlation analysis, we proved that the area of forest fires is primarily affected by maximum temperature, relative air humidity, and the amount of precipitation, as well as by global climate change associated with an increase in carbon dioxide in the atmosphere and the maximum height of snow cover. As a rule, a year before the period of severe forest fires in the south of Tyumen Oblast, the height of snow cover is insignificant, which leads to insufficient soil moisture in the following spring, less or no time for the vegetation to enter the vegetative phase, and the forest leaf floor remaining dry and easily flammable, which contributes to an increase in the fire area. According to the estimates of the CMIP6 project climate models under the SSP2-4.5 scenario, by the end of the 21st century, a gradual increase in the number of summer temperatures above 35 degrees C is expected, whereas the extreme SSP5-8.5 scenario forecasts the tripling in the number of such hot days. The forecast shows an increase of fire hazardous conditions in the south of Tyumen Oblast by the late 21st century, which should be taken into account in the territory's economic development.

Forest fires cause serious damage to mountain landforms and trigger frequent post-fire debris flows. Although post-fire debris flow exhibits time evolution, the key factors controlling its evolution remain unclear. A detailed field investigation, rainfall data collection and remote sensing analysis were conducted to study the debris flow events following the 3.08 forest fire in Xiangjiao gully. The destructive effect of forest fires, the control factors and inherent evolution mechanism of post-fire debris flow were explored. The results highlight that the great disturbance of forest fires to the hydrological response and material source supply conditions promote the outbreak of debris flows. In the rapid response stage of fire, the internal driving force of debris flow evolution is the self-healing of hydrological response characteristics of the basin, including material depletion, particle coarsening and vegetation restoration. In the long-term impact stage, the evolution of debris flows is mainly controlled by factors such as a decrease in root-soil strength caused by root rot, multi-stage gully bank landslide activity, and blockage of woody debris. A conceptual model for the evolution of post-fire debris flows is proposed based on the above evolution characteristic analysis. In particularly, this study emphasizes the catastrophic effect of woody debris during the evolution of post-fire debris flows. The research results provide scientific basis for long-term debris flow risk assessment and mitigation design in recently burnt areas.

We tested the hypothesis that the number of seedlings from the soil seed bank (SSB) in forests polluted by heavy metals and disturbed by recent fires decreases. It was also assumed that the consequences of pollution and fires for the soil seed bank are additive. We estimated the number of seedlings from the SSB of pine forests located near the Karabash copper smelter (KCS) (contaminated by Cu, Zn, Pb, and Cd) and from uncontaminated forests of the Ilmen State Reserve (ISR). In both areas, samples of the forest litter and humus horizon were taken from forests recently exposed to ground fires and long-term unburned forests. Samples were exhibited from June to September, conducting seven rounds of counting seedlings. Small peculiarities of the emergence of seedlings on the samples of the forest litter and the humus horizon were established. However, the regularities of the reaction of SSB to pollution and fire disturbances did not depend on the soil horizon. The number of seedlings on substrates from contaminated forests was 5-8 times lower than the number of seedlings on substrates from background forests. A decrease in the number of seedlings on polluted substrates was accompanied by an increase in the share of dicots in the total number of seedlings. The relationship between the number of seedlings and the age of fires was not found. The additivity of the consequences of pollution and fires has also not been established. Of the two types of damage, pollution and fires, the pollution factor is of leading importance for SSBs. The results indicate a low recovery capacity of the herb-shrub layer of polluted forests.

Forest fires can profoundly impact the hydrological response of river basins, modifying vegetation characteristics and soil infiltration. This results in a significant increase in surface flow and channel runoff. In response to these effects, many researchers from different areas of earth sciences are committed to determining emergency measures to rehabilitate river basins, intending to restore their functions and minimize damage to soil resources. This study aims to analyze the mapping detection capacity of burned areas in a river basin in Brazil based on images acquired by AMAZ & Ocirc;NIA-1/WFI and the AQ1KM product. The effectiveness of the AMAZ & Ocirc;NIA-1 satellite in this regard is evaluated, given the importance of the subject and the relatively recent introduction of the satellite. The AQ1KM data were used to analyze statistical trends and spatial patterns in the area burned from 2003 to 2023. The U-Net architecture was used for training and classification of the burned area in AMAZ & Ocirc;NIA-1 images. An increasing trend in burned area was observed through the Mann-Kendall test map and Sen's slope, with the months of the second semester showing a greater occurrence of burned areas. The NIR band was found to be the most sensitive spectral resource for detecting burned areas. The AMAZ & Ocirc;NIA-1 satellite demonstrated superior performance in estimating thematic accuracy, with a correlation of above 0.7 achieved in regression analyses using a 10 km grid cell resolution. The findings of this study have significant implications for the application of Brazilian remote sensing products in ecology, water resources, and river basin management and monitoring applications.

Acacia origena , a member of the Leguminosae family, thrives in the challenging A environmental conditions of southwestern Saudi Arabia and holds significant economic value. However, the recent occurrence of forest fires has posed a considerable threat to this species, prompting a comprehensive exploration of its resilience. This study investigates the impact of forest fires on Acacia origena , a resilient species in southwestern Saudi Arabia, with a focus on wood anatomy, soil chemical characteristics, and associated microorganisms in Al Mofareh Mountain, Alsoudah, southwestern Saudi Arabia. Fifteen samples from burned and unburned areas were analyzed. These samples were sectioned in both transverse and tangential planes to facilitate light microscopy and the analysis of wood anatomy, revealing distinctive coloration and structural changes in burned tissues. Larger-diameter specimens demonstrated greater resilience, accumulating tannins and forming tyloses to insulate damaged areas. Soil analysis indicated post-fire alterations in texture, composition, and nutrient levels. Microbial assessments highlighted varying responses in yeast and total germ colonies, it was increased by 75%. These findings provide valuable insights into the ecological responses of A. origena and soil ecosystems to fire, emphasizing the importance of comprehensive studies to guide conservation and management efforts in fire-affected regions .

The frequency of forest fires has increased dramatically due to climate change. The occurrence of forest fires affects the carbon and nitrogen cycles and react to climate change to form a positive feedback mechanism. These effects further impact the distribution of microbial biomass carbon (MBC) and microbial biomass nitrogen (MBN) and the soil microbial community structure. In addition, permafrost degradation can significantly affect the microorganisms in the soil. Based on these findings, this review examines the effects of fire intensity and post-fire recovery time on permafrost, the soil microbial community, MBC, MBN, and their interrelationships. This review demonstrated that (1) fires alter the condition of surface vegetation, reduce the organic layer thickness, redistribute snow, accelerate permafrost degradation, and even lead to permanent changes, where the restoration of the pre-fire state would require several decades or even centuries; (2) soil microbial community structure, soil MBC, and MBN negatively correlate with fire intensity, and the effects become more pronounced with increasing fire intensity; and (3) the structural diversity and stability of the soil microbial community were improved with time, and the amount of MBC and MBN increases as the years after a fire go by; it would still take more than ten years to recover to the pre-fire level. However, the relationship between permafrost degradation and soil microbes after forest fires is still unclear due to a lack of quantitative research on the mechanisms underlying the changes in soil microorganisms resulting from fire-induced permafrost degradation. Therefore, expanding quantitative studies and analyses of the mechanisms of interactions between forest fires, permafrost, and soil microorganisms can provide a scientific basis for understanding ecosystem carbon pools and dual-carbon targets in Arctic-boreal permafrost regions.

Problems Statement and Purpose. The article investigates the degradation of ecosystems in the Kharkiv region due to military actions, specifically in Kupiansk and Izyum districts. The destruction of plant cover and natural landscapes, exacerbated by fires and other war-related damages, poses long-term ecological challenges. The purpose of the study is to assess these impacts through satellite monitoring using the Normalized Difference Vegetation Index (NDVI) to identify the most affected areas and plan for their ecological restoration. Materials and Methods of Research. The research utilizes satellite images from the Copernicus Sentinel-2 platform to analyze changes in NDVI values between 2021 and 2024. This methodology allows for the detection of vegetation degradation in the studied areas and employs Geographic Information Systems (GIS) to map and visualize the extent of environmental damage. NDVI indices are analyzed for variations over time, providing insights into the effects of military actions on the region's vegetation. Results. The results of the study indicate a dramatic reduction in NDVI values in the Kupiansk and Izyum districts, particularly in 2022, which coincided with the height of military activities in the region. NDVI values in 2022 showed a 48% decrease compared to 2021, reflecting the extensive loss of vegetation due to forest fires, bombings, and the movement of heavy military equipment, which caused both direct destruction and secondary effects such as soil compaction and erosion. In 2024, some recovery in NDVI values was observed, but these remained significantly lower than pre-war levels, indicating that full ecological recovery has not yet been achieved. The study further identified key ecological hotspots where vegetation loss was most severe, particularly in areas close to conflict zones, such as military bases and frontlines. The analysis showed that forested areas suffered the greatest damage, with significant portions of these ecosystems either destroyed or severely degraded. The GIS-based analysis also revealed a correlation between the intensity of military actions and the degree of vegetation loss, with the most severely affected areas being those that experienced sustained bombardment and heavy combat. The data suggest that the recovery of these areas will require substantial effort, including reforestation, soil remediation, and the implementation of erosion control measures to prevent further degradation. Conclusions. 1). The war has led to significant environmental damage in the Kharkiv region, with substantial loss of vegetation cover and ecosystem services. 2). The NDVI analysis highlights the most affected areas, showing both the immediate and lingering effects of war on plant cover. 3). Continued monitoring and a comprehensive ecological restoration strategy are necessary to restore the region's natural landscapes, with reforestation and soil recovery being critical components. This study provides a crucial foundation for further research on the ecological impacts of warfare and offers practical recommendations for the restoration of war-torn ecosystems in Ukraine. The findings can be applied to other conflict-affected regions, emphasizing the need for a proactive approach to environmental recovery in post-war scenarios.

Forests are essential to our planet's well-being, playing a vital role in climate regulation, biodiversity preservation, and soil protection, thus serving as a cornerstone of our global ecosystem. The threat posed by forest fires highlights the critical need for early detection systems, which are indispensable tools in safeguarding ecosystems, livelihoods, and communities from devastating destruction. In combating forest fires, a range of techniques is employed for efficient early detection. Notably, the combination of drones with artificial intelligence, particularly deep learning, holds significant promise in this regard. Image segmentation emerges as a versatile method, involving the partitioning of images into multiple segments to simplify representation, and it leverages deep learning for fire detection, continuous monitoring of high-risk areas, and precise damage assessment. This study provides a comprehensive examination of recent advancements in semantic segmentation based on deep learning, with a specific focus on Mask R-CNN (Mask Region Convolutional Neural Network) and YOLO (You Only Look Once) v5, v7, and v8 variants. The emphasis is placed on their relevance in forest fire monitoring, utilizing drones equipped with high-resolution cameras.