Phytosociological classification of the thermophilous oak forests in Bulgaria: new interpretations and gaps in knowledge

Aims: The aim of this study is to classify and characterize the plant communities of the thermophilous oak forests in Bulgaria and to reveal the gradients in their floristic composition and ecology. Study area: The whole Bulgarian territory. Methods: Phytosociological classification of 716 releves collected using Braun-Blanquet's approach in oak forests from the Black Sea coasts to the upper limit of the deciduous oak forests (1200-1400 m a.s.l.). The releves data set has been subjected to numerical analysis. Results: 19 associations and subassociations and two communities were identified. Six new associations and three new subassociations were proposed. They have been assigned to the following alliances: Quercion confertae, Quercion petraeao-cerridis, Carpinion orientalis and to the new alliance Trachystemono orientalis-Carpinion betuli. Conclusions: The diversity and the ecological status of the oak forests in Bulgaria highlight the urgent need for their protection. They are in poor condition mostly due to the millennial tradition of fellings, coppicing, burning and grazing. Further research is required to investigate their diversity, ecology and dynamics - in order to gain the knowledge needed for their conservation, management and restoration.