Forest fire and aspects showed no significant effects on most mineral soil properties of black pine forests

Abstract

Forest fires and aspects strongly influence soil's physical and chemical properties. Despite many studies on wildfire impacts on soil properties, the interaction effects of multiple factors affecting soil properties and soil carbon in post-fire areas need a better understanding. This study addresses a critical question of whether and to what extent surface fire, crown fire, aspects, and combination of these factors affect soil's physical and chemical properties and soil organic carbon of a post-fire Pinus nigra forest ecosystem. We established a field experiment in a four-year-old post-fire P. nigra forest using a two-way factorial randomized complete block design with four replications. Results revealed that most soil mineral physical and chemical properties exhibited no significant differences except pH, Cu, K, and Na. The pH and N also significantly decreased with soil depth. The surface soil organic matter (SOM) exhibited significant differences among types of forest fire and combined forest fire types and aspects. Depending on forest fire types and aspects, the post-fire sites recovered 20 % to 52 % of the lost SOM four years after the fire. Our results suggest that forest fires do not necessarily cause long-term detrimental effects on soil mineral nutrients and organic carbon. The north-facing slope post-fire areas exhibited a higher recovery rate than the south-facing slope, indicating that post-fire management and rehabilitation should prioritize the crown-fire, south-facing slopes.