Runoff and erosion from volcanic soils affected by fire: the case of Austrocedrus chilensis forests in Patagonia, Argentina

Abstract

Aims We characterized the runoff and erosion from a volcanic soil in an Austrocedrus chilensis forest affected by a wildfire, and we evaluated the effects of a mitigation treatment. Methods Rainfall simulations were performed in the unburned and burned forest, with and without vegetation cover, and under a mitigation treatment. Results After the wildfire, the mean infiltration rate decreased from 100 mm h−1 in unburned soils to 51 and 64 mm h−1 in the burned with and without litter and vegetation cover, respectively. The fast establishment of bryophytes accelerated the recovery of soil stability. Sediment production was negligible in the control plots (4.4 g m−2); meanwhile in the burned plots, it was 118.7 g m−2 and increased to 1026.1 g m−2 in the burned and bare plots. Total C and N losses in the control plots were negligible, while in the burned and bare plots the organic C and total N removed were 98.25 and 1.64 g m2, respectively. The effect of mitigation treatment was efficient in reducing the runoff, but it did not affect the sediment production. Conclusions These fertile volcanic soils promoted the recovery of vegetation in a short time after the wildfire, diminishing the risk of erosion.