Environmental Engineering Reference
In-Depth Information
Chapter 12
Afforestation and Reforestation:
The Sicilian Case Study
Juliane Rühl, Luciano Gristina, Tommaso La Mantia, Agata Novara
and Salvatore Pasta
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 variabil-
ity, 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-dom-
inated 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 agri-
cultural abandonment depends on bioclimate: the highest SOC accumulation was
recorded in the meso-mediterranean bioclimate, intermediate in the thermo-medi-
terranean, and the lowest in the supra-mediterranean bioclimate. Data showed that
for C sequestration in the soil, artificial afforestation is not convenient in compari-
son to natural afforestation by spontaneous secondary succession processes.
12.1 Introduction
In the Mediterranean region, lands cultivated since ancient times are today subject
to two contrasting trends: intensification or abandonment. Since the 1950s, vast
areas of Southern Italy have been afforested with the aim of soil conservation and
