The floodplain woods of Tuscany: Towards a phytosociological synthesis

The recent Landscape Plan of Tuscany Region pays particular attention towards the floodplain woods, for their conservation concern, landscape, and historical importance. The floodplain forest vegetation is defined as the natural and semi-natural wood vegetation located close to the rivers and submerged only during exceptional flooding. We gathered 180 both published and unpublished relevés coming from Tuscany and carried out in floodplain woods, where Alnus glutinosa, Fraxinus angustifolia subsp. oxycarpa, Quercus robur, Ulmus minor, Carpinus betulus, Populus nigra, P. alba and Salix alba were dominant, alone or in consociation with each other. On this dataset we performed a multivariate analysis, and the resulting groups were characterized by several points of view: floristic, ecological, chorological, by mean of diagnostic species, with the use of EIV. Moreover, their distribution in Tuscany was better defined. According to our results, six associations were found to be present in Tuscany. Thereby, one new association and three new subassociations were proposed. The syntaxonomic arrangement above the association level was discussed, with particular attention to the Italian Fraxinus angustifolia subsp. oxycarpa-rich communities. Finally, a comparison with the Annex I habitat types (sensu Directive 92/43/EEC) was carried out.