Relationship of chemical and biochemical properties of soil to recurrence and severity of forest fire in South Western European Atlantic environments

Abstract Background and aims Changes in fire regimes (extension, severity and recurrence), aggravated by climate change and abandonment of agricultural land, produce a large buildup of fuel in the environment and cause high severity and recurrence of forest fires. Soil can be a good indicator of the effects of fire on the whole ecosystem. The main objective of this study was to identify the effects of the severity and recurrence of fires on chemical and biochemical soil properties in short and medium time and interpret the interaction of plants on these properties. Methods To know the effects of forest fires on soil properties 4 recurrence-severity scenarios were studied at short and medium time after a big forest fire. The analysed properties were pH, %CO, %N, available P, β-glucosidase, urease, phosphatase and microbial biomass C. Results After fire some properties showed a continuous increase throughout the study time (pH, percentage CO, microbial biomass C, β-glucosidase and urease) while other properties (percentage N, available P and phosphatase) experienced a peak at 30 months and then regressed to values at 18 months. Conclusion Forest fire severity strongly modified the chemical and biochemical properties of the soil, favoring the increase of most of them, in some continuously over time and in others punctually. Fire recurrence only had a prominent role in the postfire dynamics of soil pH. The annual changes in soil properties were mainly related to regrowth woody species.