Short-Term Effects of Burn Severity on Post-Fire Runoff and Soil Erosion in Pine Forests

Abstract

Fires significantly impact the hydrological processes of forest ecosystems by increasing runoff and sediment yield due to alterations in soil properties and the loss of surface vegetation. This study demonstrated that high-severity fires reduced soil bulk density and increased soil porosity immediately after the fire. However, little change was observed in areas affected by low-intensity fires or in unburned regions. Strong water repellency persisted in the top 5 cm of soil where crown fuel consumption occurred, whereas weak or no hydrophobicity was detected in areas affected by foliage necrosis or in natural forests. High-intensity fires led to increased runoff and soil erosion. However, limited soil heating at foliage necrosis sites did not affect post-fire runoff or soil erosion. This was attributed to the site's low water repellency and the presence of litterfall, which protected the soil surface. Despite the relatively small size of erosion plots and the short duration of field measurements, this study provided a quantitative understanding of the immediate and short-term effects of fire on the hydrological and geomorphological responses of burned forests.

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