Post-fire management and splash erosion in a chestnut coppice in southern Switzerland

Abstract

We evaluated the impact of different post-fire management options in a chestnut coppice on surficial processes by comparing splash erosion, mean weight diameter (MWD) and stability of soil aggregates, and the development of soil cover on the following three plots with an undisturbed forest plot: fire without post-fire treatment; fire followed by clear-cutting; fire followed by clear-cutting 1 year later. Splash erosion was monitored on an event basis ( n=44) over two growing seasons with splashboards, MWD and stability of aggregates were determined by dry and wet sieving, respectively, of soil samples collected three times throughout the 14-month study period, and soil cover was estimated six times. In the first year, clear-cutting did not result in an increased rate of splash erosion compared with the untreated, burned coppice, nor did it result in a deterioration of aggregate stability, although both fire-affected plots showed a decrease in MWD compared to the control plot. In the second year, splash erosion decreased substantially on these two plots, whereas the freshly cleared plot maintained splash erosion rates characteristic for the first year without a concomitant deterioration of MWD or aggregate stability. The strongest decrease in splash erosion occurred on the plot subject to immediate clear-cutting, which also experienced the most rapid development of soil cover. We conclude that post-fire clear-cutting does not have any adverse effects, as judged by splash erosion and measures of soil aggregation, beyond the fire-related ones. Due to the persistence of the erosion in the first year, however, we recommend immediate intervention where justified by economic considerations.