This association of Alnus glutinosa carr occurs in acidic and nutrient-poor waterlogged habitats, which support occurrence of Betula pubescens and Picea abies. The herb layer is composed of acidophilous sedges and other species of nutrient-poor soils. The moss layer is well developed, with a significant participation of Sphagnum spp. In the Czech Republic this association occurs mainly in the Doksy region of northern Bohemia, but it has also been recorded in other areas of the Bohemian Massif.