Abstract

TALAMO, Andrés et al. Post-fire soil erosion control: using “fajinas” in a dry mountain forest (Salta, Argentina). Ecol. austral [online]. 2017, vol.27, n.3, pp.415-420. ISSN 1667-782X.

Wildfires in mountain forests can trigger changes in rates of infiltration and runoff, increasing sediment flow downhill. Therefore, it is urgent to design and implement soil erosion control techniques on burned slopes. A simple and economic method is the construction of “fajinas” (cylindrical palisade built with braided branches). Our objective was to evaluate the effectiveness of the “fajinas” method in controlling sediment trawling on a burned slope located in the Serranía de Tres Cerritos (Salta, Argentina). We experimentally evaluated the effect of placing different numbers of “fajinas” (0, 2 and 3) and in three different positions on a burned slope (high, medium and low) on the amount of ash retained (measuring ash profile height). We found that the greater the number of “fajinas”, the deeper the ash profile was, showing a be��er control of sediment trawling. In addition, “fajinas” located in the lower or middle position of the slope controlled more effectively the sediment drag. Both factors acted independently. Although the cost/work of the construction of a control system with rows of 3 “fajinas” is greater (by 50%) compared to a system with only 2 rows of “fajinas”, the gain observed in the control of sediments exceeded 64% when working with 3 “fajinas”. This justifies the recommendation of implementing systems with 3 “fajinas” as to control sediment trawling and soil erosion on slopes burned in future wildfire events in dry mountain forests.

Keywords : Ash accumulation; Run-off; Soil loss; Wildfires.