Strategies for the re-naturalization of reforestation: the case study of the Sicilian clay hills

Abstract

Over the last decades many areas have been reforested along Europe, with great proportion been made with exotic species. Very often these reforestations do not evolve in more diverse configurations, where some kind of management can be necessary to try to enhance this evolution. The hole is a silvicultural technique consisting in open small gaps to create favourable conditions for the establishment of other species changing the former structure, microclimate and competitive conditions mirroring this natural processes that occurs in structured and mature forests. The best size of the hole seems to be around 500 m², as small holes may not change significantly the conditions and larger holes seems to favour degradation processes like soil erosion and loss of organic layers. The afforestaion of the Santa Ninfa Natural Reserve (Trapani Province, W-Sicily) were made using essentially Pinus spp. and Eucalyptus camaldulensis. Particularly, this last specie occur in high density monospecific forest structure covering 19 ha (8% of the reserve), where practically no kind of management has been made until now and very few natural regenerations is observed. The aim of the study was to verify the effectiveness of the restoration actions combining the hole technique and planting native species with different management levels.