Wildfires are increasingly recognized as a critical driver of ecosystem degradation, with post-fire hydrological and soil impacts posing significant threats to biodiversity, water quality, and long-term land productivity. In fire-prone regions, understanding how varying fire intensities exacerbate runoff and erosion is essential for guiding post-fire recovery and sustainable land management. The loss of vegetation and changes in soil properties following fire events can significantly increase surface runoff and soil erosion. This study investigates the effects of varying fire intensities on runoff and sediment yield in the Kheyrud Educational Forest. Controlled burns were conducted at low, moderate, and high intensities, along with an unburned plot serving as the control. For each treatment, three replicate plots of 2 m2 were established. Runoff and sediments were measured over the course of 1 year under natural rainfall. In addition, key soil physical properties, including bulk density, penetration resistance, and particle size distribution (sand, silt, and clay fractions), were assessed to better understand the underlying mechanisms driving hydrological responses. The results revealed that bulk density and penetration resistance were lowest in the control and highest for the high-intensity fire treatment. A significant correlation was observed between bulk density, penetration resistance, and both runoff and sediment production. However, no significant correlation was found between runoff and soil texture (sand, silt, and clay content). Fire intensity had a pronounced effect on runoff and sediment, with the lowest levels recorded in the control and low-intensity fire treatment, and the highest in the high-intensity fire treatment. The total annual erosion rates were 0.88, 1.10, 1.57, and 2.24 tons/ha/year for the control, low-, moderate-, and high-intensity treatments, respectively. The study demonstrates that high-intensity fires induce substantial changes in soil structure and vegetation cover, exacerbating runoff and sediment loss. To mitigate post-fire soil degradation, proactive forest management strategies are essential. Preventive measures-such as reducing fuel loads (e.g., removing uprooted trees in beech stands), minimizing soil compaction and vegetation damage during logging operations, can help reduce the ecological impact of wildfires. These findings provide a scientific basis for adaptive management in fire-prone forests, addressing urgent needs to balance ecological resilience and human activities in wildfire-vulnerable landscapes.

Characterization of vegetation effect on soil response is essential for comprehending site-specific hydrological processes. Traditional research often relies on sensors or remote sensing data to examine the hydrological properties of vegetation zones, yet these methods are limited by either measurement sparsity or spatial inaccuracy. Therefore, this paper is the first to propose a data-driven approach that incorporates high-temporalresolution electrical resistivity tomography (ERT) to quantify soil hydrological response. Time-lapse ERT is deployed on a vegetated slope site in Foshan, China, during a discontinuous rainfall induced by Typhoon Haikui. A total of 97 ERT measurements were collected with an average time interval of 2.7 hours. The Gaussian Mixture Model (GMM) is applied to quantify the level of response and objectively classify impact zones based on features extracted directly from the ERT data. The resistivity-moisture content correlation is established based on on-site sensor data to characterize infiltration and evapotranspiration across wet-dry conditions. The findings are compared with the Normalized Difference Vegetation Index (NDVI), a common indicator for vegetation quantification, to reveal potential spatial errors in remote sensing data. In addition, this study provides discussions on the potential applications and future directions. This paper showcases significant spatio-temporal advantages over existing studies, providing a more detailed and accurate characterization of superficial soil hydrological response.

The role of structural planes in controlling mudstone landslides is a key issue in the study of geo-disasters in the Loess Plateau of China. In this study, the effects of sliding-control structures on the mechanisms of mudstone landslides are investigated via three model experiments with different slope structures. The results show that the hydrological response and failure mode of the experimental slope vary with the structural conditions. The vertical joints serve as preferential seepage paths, which accelerate rainfall infiltration, resulting in earlier responses of volumetric water content and pore water pressure. With the incorporation of vertical joints, the slope failure mode tends to transform from shallow failure to deep-seated failure. The presence of a weak interlayer leads to significant increases in the velocity and runout of the sliding mass. The variation in the slope failure extent and deformation characteristics with varying sliding-control structures further changes the temporal and spatial distributions of volumetric water content and pore water pressure. The different slope failure modes correspond to different sliding-control mechanisms, which are dominated by the types of structural planes and their interactions with hydrological responses. In the action of these mechanisms, pore water pressure and seepage force play significant roles in the reduction of effective stress and shear strength.

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.