New approach for the classification of the Black Pine forest communities in Bulgaria was made in the paper. The analysis of forest pytocoenoses from Vlahina, East and West Rhodopi and Balkan Range Mountains confirmed their separation into two classes – Quercetea pubescentis (low-altitudinal) and Erico-Pinetea (high-altitudinal). The second class is represented from one polymorphic association Seslerio latifoliae-Pinetum nigrae whereas the other group is represented from two new associations. The association Junipero deltoidi-Pineteum pallasianae is more related to the surrounding thermophilous oak forests as well as the association Lathyro laxiflori-Pinetum pallasianae is more similar to the hornbeam and beech forests.

This paper deals with relationships between vegetation of Macedonian pine (Pinus peuce) and soils developed on different parent materials on the territory of North Macedonia. We analysed the floristic composition at localities on limestone, on scree of dolomite marble and on scree of silicate. On limestone and scree of dolomite marble, rendzinas on hard limestone and dolomite have developed, and on silicate parent material brown forest soils. The vegetation was sampled according to the Braun-Blanquet approach. DCA and indicator values were used for ecological interpretation of the vegetation patterns. The mechanical and chemical properties of soil and textural classes were also processed. An evident increased presence of carbonates in the soil of scree of dolomite marble on Nidže Mountain was observed, unlike that on Shar Mountain which has formed on typical limestone. Although it is a forest community dominated by the same species, differences between the massifs, the precipitation regime, geology, differences in soil properties in relation to the appearance of carbonates and pH values, and other factors, result in differences in their floristic composition and are the reason for the distinction between the two groups. On silicate on Nidže Mountain, Macedonian pine forests have also developed on brown forest soils, with a different floristic composition to that of the other group on carbonate (dolomite and limestone).

Aesculus hippocastanumL. (European Horse-chestnut) constitutes a biogeographical relict species of the Balkan Peninsula, occurring in isolated and topographically distinct localities in Albania, Bulgaria, Greece and North Macedonia. Despite its great botanical, ornamental and pharmaceutical value, a thorough investigation ofAe. hippocastanumhabitat diversity in its native distribution range has not been conducted yet. The present study aims at the syntaxonomic classification and ecological features of plant communities dominated by this species across its overall native distribution range. On the basis of 55 phytosociological relevés, five ecologically, floristically, and spatially well differentiated clusters were identified, with the main revealed gradients of differentiation being geographic location (longitude, latitude), altitude, annual precipitation and precipitation seasonality. The distinct microhabitats with a special refugial character where these plant communities occur meet the species’ requirement for relatively high air and soil humidity. They have allowed the preservation ofAe. hippocastanumthrough time highlighting their great conservational value. The last one could be useful for the implementation of some appropriate measures for effective conservation of these communities.

Identification and characterization of forest habitats on the territory of the “Central Balkan” National Park in Bulgaria was carried out. The national park is one of the most valuable and largest protected areas in Europe – second category according to the International Union for Conservation of Nature (IUCN). Based on 786 phytosociological relevés, a total of 17 different habitat types, according to EUNIS were identified and mapped. The habitats were ecologically characterized by Ellenberg indicator values and their area was determined. A comparison was made with the areas determined in previous works. The applied method is suitable for the purposes of managing protected territories and zones, for monitoring the status and especially the conservation status of the habitats. The results and especially the established new habitats support this point of view.

This study deals with the diversity of forest vegetation in the Slivenska Mountain (Eastern Stara planina) and presents a contemporary classification scheme for the identified syntaxa. A total of 137 relevés were collected and analyzed using specialized software (JUICE 7.0 and PC-ORD Version 4). As a result, forest vegetation is classified into 10 associations, 3 subassociations, 4 variants and 5 communities They belong to 7 alliances, 5 orders and 3 classes: Carpino-Fagetea sylvaticae, Quercetea pubescentis and Alno glutinosae-Populetea albae. The recorded 18 distinguished vegetation groups show a relatively high diversity of forest plant communities of the study area.