This alliance comprises open forests of Pinus nigra and P. sylvestris occurring in the Eastern Alps, mainly on limestone or dolomite slopes. They are particularly common in the dry valleys of the Central Alps, but also occur in the Northern and Southern Alps and some adjacent regions. In the Alps they are characterized by the frequent occurrence or dominance of Erica carnea in their herb layer, but in the Czech Republic this species occurs in different vegetation types. The herb layer of these forests includes some continental species and particularly several drought-adapted species typical of limestone areas at the edges of the central European mountain ranges. In the Czech Republic this alliance is found in two relatively dry serpentine areas in the Bohemian-Moravian Uplands.