earticle

영어

Fire-induced hydrophobic soil layers inhibit rainfall infiltration, increase surface runoff, and contribute to soil erosion and secondary disasters such as landslides. Understanding the spatiotemporal patterns of soil water repellency after wildfires is crucial. This study analyzed temporal changes in soil water repellency according to wildfire burn severity (severe, moderate, low) and slope steepness (steep, moderate, gentle) in wildfire-affected forests in South Korea (Yeongdeok, Uljin, and Hapcheon) between 2022 and 2023. Soil water repellency was assessed immediately after the fire and at 6, 12, and 24 months using the Molarity of Ethanol Droplet (MED) method, with measurements taken at 1-cm intervals down to 5 cm soil depth. Higher wildfire burn severity and steeper topography formed strong water-repellent layers (MED ≥5) down to 5 cm depth. In the Yeongdeok forest, strong repellency at the 0–1 cm depth was observed, representing 66% in severely burned moderately sloped and moderately burned gently sloped sites, and 100% in moderately burned steeply sloped sites, but fully recovered to hydrophilic soils by 12 months. In the Uljin forest, soil water repellency persisted down to 4 cm depth at 12 months but largely disappeared by 24 months. In the Hapcheon forest, hydrophobic soil characteristics extended to 5 cm soil depth and persisted at 2–4 cm depths even after 24 months in severely burned areas.