Ostrya carpinifolia woods have been extensively studied in C-Italy, while they lack specific researches and a clear phytosociological scheme in the southern part of the country. We have analyzed original and published relevés from Campania and Calabria regions, and we have compared them with bibliographic data from central Italy. The existing southern Italian Ostrya-dominated associations are revised as for their character species and bioclimatic position. Floristic analysis underlines a set of biogeographically relevant species which differentiate these communities from their C-Italian analogous.
A new suballiance Festuco exaltatae-Ostryenion carpinifoliae is therefore described within Carpinion orientalis, coherently with the framework already adopted for Quercus cerris woods. The syntaxon can be subdivided into two associations. Festuco-Aceretum includes different types of mixed woods growing at low elevations, in the warm-humid maritime climate of the Campania and Calabria Thyrrenian coasts (mainly in the mesomediterranean belt). Seslerio-Aceretum obtusati is the name to be used for Ostrya-woods of the mesotemperate and supratemperate belt; a subassociation for more markedly cool and humid woods can be further differentiated (described here as galietosum laevigati).
Carpinion orientalis in the Italian peninsula (i.e. not including the Alps) contains now five suballiances: Lauro-Quercenion pubescentis, describing termophilous Quercus pubescens woods; Cytiso sessilifolii-Quercenion pubescentis, referring to comparatively continental Quercus pubescens woodlands of the C-Apennines; Campanulo mediae-Ostryenion, Ostrya-woods restricted to the NW sector of the Peninsula; Laburno anagyroidis-Ostryenion, mesophilous Ostrya- and mixed-woods of the mesotemperate and supratemperate belts of the N- and C-Apennines; and Festuco exaltatae-Ostryenion, Ostrya- and mixed-woods of the oceanic mesotemperate and supratemperate belts of the S-Apennines.