Phytodiversity of Pyrogenic Formations of the Usman Forest (Voronezh Oblast)

Postfire (2010) formations of Pinus sylvestris and Betula pendula (51°48′30.1′′ N, 39°23′58.4′′ E) have been studied. This article presents the results of these studies for 2015–2016. Descriptions of these formations have been carried out since 2012. Methods for the analysis of the structures of plant communities are of especial importance, both for an understanding of their annual ecological state and the identification of plant resistance to the pyrogenic factor. Information on the beginning of restoration of the phytocenosis structure and flora, on the change of dominants in vegetation layers, an increase of the projective cover, and the formation of forest phytocenosis is given on example of common and pyrogenic associations of these formations. A decrease in weed species abundance and their projective cover was noted. The current list of flora includes 84 species from 75 genera, 33 families, and 2 divisions: Pinophyta and Magnoliophyta. The dominant families are Poaceae with 12 species (14.1%), Asteraceae with eight species (9.4%), and Fabaceae with six species (7%). The small list of dominant families with a small number of species confirms the large disturbance of flora by the pyrogenic factor. The dominance of rhizome plants (42 species, 44.6%) and a small number of cespitose plants (4 species, 4.8%) indicates the advantage of the forest phytocenotic group. The presence of a xerophytic group (15 species, 17.9%) indicates increased insolation and a decreased moisture content in these postfire formations. Eight geoelements and 14 types of habitats have been identified. The European one predominates, with 53 species (63.1%) and 12 types of habitats.