Structural analysis of woody species in Mediterranean old fields.

The first part of this study provides an overview on Sicilian olive systems. Subsequently, the study describes the different typologies of cultivated agroforestry systems present in South-Eastern Sicily employing olive trees in association with other Mediterranean tree species, in particular for the production of firewood, coal and animal food (downy or pubescent oak, holm oak, cork oak), but also in association with forage or grazing species (oat, barley, vetch, etc.) or cereals. The study shows that Sicilian agroforestry systems are much more diversified than it was known so far. In the second part, the study describes the spontaneous colonization processes by plants, observed in abandoned olive agroforestry systems and leading to the formation of more complex ecosystems (renaturation). Most of the previously described agroforestry systems are at present subject to abandonment. Our analysis of secondary succession dynamics shows how woody species, and above all those species which are part of the cultivated system, rapidly colonize abandoned areas, so that a maquis-wood is formed within few decades.