Short‐term Impact of Coppice Management on Soil in a Quercus ilex l. Stand of Sardinia

Abstract

The short-term impact of coppice-with-standards management on soil in a Mediterranean holm oak forest was assessed to contribute to address appropriate recommendations to minimize possible negative effects of the silvicultural practices. For this purpose, soil surface features and topsoil properties were investigated in two representative areas located in a public forest in southwest Sardinia (Italy) and coppiced in the periods November 2012-March 2013 and November 2011-March 2012, respectively. Regardless of differences in soils and slope gradient, the same management, in terms of final density of trees standing after the clear-cut and accumulation of brushwood in strips along the maximum slope gradient, was applied in both areas. Field observations and laboratory data highlighted the disturbances caused to the soil by the silvicultural practices in the stands when compared with the undisturbed stands. These disturbances involved the almost complete removal of organic horizons, with consequent negative impact on organic carbon content, and the activation of erosion processes, mostly related to rainsplash erosion. Although soil mobilization locally largely exceeded the tolerable erosion rates, no extreme rainfall events occurred after the coppicing to produce critical situations at the catchment level. The adjustment of the final density of trees standing after the clear-cut in relation to soil properties, slope gradient and the possibility of extreme rainfall events, a different brushwood management and the restriction to the passage of wild animals would have strongly reduced the negative impacts on soils.

A critical analysis of Vacca, A., Aru, F., and Ollesch, G. (2017). Short‐term impact of coppice management on soil in a Quercus ilex L. Stand in Sardinia. Land Degradation & Development, 28(2), 553–565

“…With regard to the thickness of the surface horizons, shown in Tables 2 and 4 in Vacca et al (), only a decrease in litter thickness is reported, whereas the thickness of horizon‐A is uniform in all plots (both cut and undisturbed) in both the S'Isteri (average: 6.75 cm; SD : 5.85) and Su Caraviu (average: 21.92 cm; SD : 5.7) stands. The high standard deviation of S'Isteri is due to two particularly high values of soil thickness (15 and 22 cm) detected in the area undergoing coppice cutting (Figure ).…”

“…The high standard deviation of S'Isteri is due to two particularly high values of soil thickness (15 and 22 cm) detected in the area undergoing coppice cutting (Figure ). Data related to organic carbon content in horizon‐A that are reported in Tables 2 and 4 in Vacca et al () show no significant differences between the covered and cut areas (S'Isteri: average = 11.1%, SD = 3.4%; Su Caraviu: average = 9.6%, SD = 2.3%; Table ). The values of organic carbon content in Table 5 (Vacca et al, ) seem to be derived (not reported) from the aggregated analysis of the surface soil (horizon‐A) and litter (horizon‐O).…”

“…The presence of superficial erosion was not detected, according to the values shown in Table 5 (Vacca et al, ); there are no significant differences between coppice areas and undisturbed areas ( p ‐values of the Kruskal–Wallis statistical analysis >0.05) in either the S'Isteri or the Su Caraviu stand. The only significant p ‐value ( p = 0.0244) for erosion/deposit for ‘all CWS plots versus all’ shown in the first column of Table 5 (Vacca et al, ) should not be considered because it describes cumulative statistics of sites having different geomorphological characteristics (slope and exposure) and soil behavior (granulometric characteristics).…”

“…In red, the values refer to the tests in the area undergoing a cut; in blue, the values refer to undisturbed areas. The boxplots show the distribution of the infiltration rates; there are no statistically significant differences (data from Vacca et al, ) [Colour figure can be viewed at wileyonlinelibrary.com]…”

“…The organic horizon is significantly thinner on the steeper slopes. The boxplots represent the distribution of the slopes of the plots (in red, the slopes are in the coppiced area; in blue, the slopes are under undisturbed vegetation; data from Vacca et al, ) [Colour figure can be viewed at wileyonlinelibrary.com]…”