In the fluvio-glacial woodland landscape of the Zvenigorod biological station (located within the mixed forest subzone, in the center of the Russian Plain), in order to identify ecological differences between syntaxa of coniferous and mixed forests referred to the classes Carpino–Fagetea and Vaccinio–Piceetea, 536 geobotanical relevées were analyzed those were collected in 2004–2016. Resulting from ecological-floristic classification (according to the Braun-Blanquet approach), 5 associations were established in this woodland (including 2 subassociations, 3 variants, particularly new xeromesophytic variant, named Vaccinium vitis-idaea, of zonal subass. Rhodobryo–Piceetum caricetosum pilosae and new sub-taiga variant named Asarum europaeum of south-taiga subass. Melico–Piceetum typicum) and 1 derivative community. Multidimensional ordination based on the similarity of floristic composition, phytoindication of the ecological regime using rank scales of H. Ellenberg, and analysis of the syntaxa localization in ecotopes at different positions in the river valley and with different soil characteristics (using a geographic information system based on large-scale maps). The results of ordination and phytoindication showed that floristic differences between forest classes are consistent with soil reaction and nitrogen content, and at the level of associations in the same class - with a moisture regime. Frequency analysis of the syntaxa distribution by ecotopes revealed that the forests of the zonal syntaxon (subass. Rhodobryo–Piceetum caricetosum pilosae var. typica) have a tendency to grow on well-humified soils without gleyzation, whereas the forest syntaxon of the more northern range (subass. Melico–Piceetum typicum var. Asarum europaeum) do on gleyed soils. The specific confinement connected with the granulometric soil composition has not been revealed for the studied forests. In the surveyed fluvio-glacial woodland landscape, xeromesophytic mixed forests dominate at the local watershed, those combine features of two classes, but basing on floristic criteria have to be referred to the nemoral class Carpino–Fagetea.
Keywords: hemiboreal forests, Braun-Blanquet classification approach, multidimensional ordination, fluvio-glacial landscape in the center of the Russian Plain