Bibliographie complète

Here is proposed the declination of the Quer- cetea pubescentis Doing-Kraft ex Scamoni & H. Passarge 1959 class, for the second ver- sion of the French vegetation prodrome (PVF2). It contains 35 associations, 9 sub-al- liances, 7 alliances and 3 orders. This class comes from the spliting of the Querco robo- ris-Fagetea sylvaticae Braun-Blanq. & Vlieger in Vlieger 1937 “ superclass », chosen in the first French vegetation prodrome (PVF1, Bar- dat et al. 2004). Three orders compose this class. The Quer- cetalia pubescenti-petraeae Klika 1933 corr. Moravec in Béguin & Theurillat 1984 is the central one, and contains a new alliance for acidophilous white oak forests: the Avev- ello flexuosae-Quercion pubescentis. The Cot- ino coggygriae-Fraxinetalia orni Jakucs 1960 nom. invers propos. gathers mainland ligu- rian and thyrenean forests but also corsican ones. The choice of a third order, the Querco petraeae-Carpinetalia betuli Moor ex R. Boeuf 2014, is the main change between PVF1 and this PVF2. It is based on the Carpinion bet- uli Issler 1931 alliance, reestablished in its original diagnoses as oak-hornbeam forests, without beech because of a too dry climate. In the PVF1, both beech-oak-hornbeam and dry oak-hornbeam forests were put in the Carpinion betuli. For nomenclatural, floris- tical, structural and ecological reasons, dry oak-hornbeam forests are now separated not only from beech-oak-hornbeam for- ests but aslo from oak-hornbeam copices in witch beech has been eliminated by agri- cultural and forestry practices. The Carpin- ion betuli must only be used for “ true » dry oak-hornbeam forests. Beech-oak-horn- beam (including copices) are now con- cerned by the new Carpino betuli-Fagion sylvaticae R. Boeuf, Renaux & J.-M. Royer in R. Boeuf 2011 alliance, witch belongs to another class (see Renaux et al. 2019d). Keywords : Querco roboris-Fagetea sylvati- cae Braun-Blanq. & Vlieger in Vlieger 1937, Carpinion betuli Issler 1931, white-oak for- ests, Quercus pubescens, oak-hornbeam for- ests, supramediterranean, hophornbeam forests.