The oldest Pinus nigra plantations in the central Apennines: distribution and floristic-vegetational characterisation

This paper represents the first syntaxonomic study on the Pinus nigra subsp. nigra artificial stands in the Apennines. It refers exclusively to the mature Pinus nigra forest plantations in the central Apennines that were planted before the 1950s, and then not managed. The mature Pinus nigra forest plantations in the central Apennines are distributed within four National Parks, on limestone substrata, mainly with southern aspects and rugged slopes, and at elevations ranging from 655 m to 1670 m a.s.l.. Two new phytosociological associations are described here and classified in the alliance Junipero communis–Pinion nigrae: Orthilio secundae–Pinetum nigrae and Digitalidi micranthae–Pinetum nigrae. The association Orthilio secundae–Pinetum nigrae comprises the relative mesophilous mature pine forests of the supratemperate thermotype in the plant landscape context of the alliance Aremonio agrimonioidis–Fagion sylvaticae potential vegetation belt. The Digitalidi micranthae–Pinetum nigrae comprises the thermophilous pine forests occurring on rocky stands within mesotemperate and lower supratemperate thermotypes in the potential belt of alliance Carpinion orientalis woods. The comparison of these two new associations and the phytosociological literature concerning the natural communities of Pinus nigra in the Apennines highlights their floristic and coenological autonomy.