Classification of the relict forest communities of Palla’s Black Pine (Pinus nigra subsp. pallasiana) in Bulgaria

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.