Afforestation and reforestation: the Sicilian case study

Abstract

In some regions of the world such as the Northern Hemisphere, the abandonment of agricultural land is one of the most widespread forms of land use change. In general, abandonment is followed by colonization by herbaceous and woody plants. Since the 1950s, wide areas of Southern Italy have been afforested for soil conservation improvement. In order to quantify the effects of agricultural abandonment and artificial afforestation on soil organic carbon (SOC), a dataset of 48 Sicilian sites has been analyzed. Because of their high environmental variability, these sites can be considered as representative of Southern Italy and in general of the Mediterranean basin. Soil samples were taken throughout all bioclimates in different successional stages (cultivated areas: orchards, cereal crops, herb-dominated plant communities, grasslands dominated by perennial grasses, garrigues and low shrublands, maquis, natural forests and in nearby artificially afforested sites (Pine plantations)). The study confirmed that SOC accumulation after agricultural abandonment depends on bioclimate: the highest SOC accumulation was recorded in the meso-mediterranean bioclimate, intermediate in the thermo-mediterranean, and the lowest in the supra-mediterranean bioclimate. Data showed that for C sequestration in the soil, artificial afforestation is not convenient in comparison to natural afforestation by spontaneous secondary succession processes.