Altitudinal distribution (5 states)
1 eu-Mediterranean belt (potential vegetation: evergreen Quercus ilex forest)
2 submediterranean belt (deciduous Quercus-Carpinus forests)
3 montane belt (Fagus forests, marking treeline in the Apennines)
4 Oroboreal belt of the Alps (natural Picea abies, and Larix-Pinus cembra stands)
5 above treeline (both Alpine and oromediterranean)
For Sardegna, which hosts a very peculiar vegetation somehow resembling that of parts of the Iberian peninsula, and where the beech belt is missing, the altitudinal subdivision was adjusted as to fit that proposed by ARRIGONI (1968); this means that in Sardegna the "submediterranean" belts may be dominated by an evergreen upland vegetation, and the "montane" belt by deciduous oaks, or by remnants of ancient woodlands with Taxus and Ilex.