A phytosociological study of the deciduous oak woods of Sardinia (Italy)

We present here the results from a phytosociological and synchorological study of the deciduous oak woods of Sardinia. This vegetation analysis has
allowed the individuation of three new associations: Lonicero implexae-Quercetum virgilianae, Ornithogalo pyrenaici-Quercetum ichnusae and
Glechomo sardoae-Quercetum congestae. The Lonicero implexae-Quercetum virgilianae association includes the woods on calcareous substrata
spread throughout Northern Sardinia, which can occasionally be found in southern areas; the first of these are rich in mesophilous species and are
attributed to the subassociation cyclaminetosum repandi, while the others are referred to quercetosum virgilianae. The Ornithogalo pyrenaici-Quercetum
ichnusae association, more widely distributed in Central-Northern Sardinia, includes the climatophilous deciduous woods that are found on lithological
substrata of a non-carbonatic nature, and in particular, on andesites, trachytes and metarenites. The typical aspect is referred to the subassociation
cytisetosum villosi, while the subassociation ilicetosum aquifolii includes the more mesophilous woods on basaltic substrata. The Glechomo sardoae-
Quercetum congestae association always includes the woods found on the non-carbonatic substrata in the higher altitude areas with an oceanic
pluviseasonal temperate bioclimate. Of this, the subassociation quercetosum congestae, on the granite areas, and oenanthetosum pimpinelloidis, on
those metamorphic and of basalt, are proposed. At the higher hierarchical levels, the association Lonicero implexae-Quercetum virgilianae is referred
to the endemic Sardinian-Corsican suballiance Clematido cirrhosae-Quercenion ilicis, of the alliance Fraxino orni-Quercion ilicis, while for the
other associations the new suballiance Paeonio morisii-Quercenion ichnusae, (holotypus: Glechoma sardoae-Quercetum congestae ass. nova) particular
to the Sardinian biogeographic subprovince, is proposed, of the alliance Pino calabricae-Quercion congestae, the order Quercetalia pubescentipetraeae,
and the class Querco roboris-Fagetea sylvaticae.