This association includes mountain bogs dominated by up to 2 m tall stands of Pinus mugo and P. ×pseudopumilio reaching a cover up to 90 %. This vegetation occurs on shallower peat with a more strongly fluctuating water table than adjacent vegetation of open bogs. It often forms the border zone between open bogs and adjacent forests. In the Czech Republic this vegetation occurs in some mountain ranges of the Bohemian Massif along the international border.