Pinus uncinata forests of steep calcareous ubacs (north facing slopes) of the Pyrenees with very superficial soil and a mostly grassy herb layer comprising Sesleria caerulea, Festuca gautieri, Pulsatilla alpina, Valeriana montana, Salix pyrenaica, Hepatica nobilis, Deschampsia flexuosa, Pyrola uniflora, Listera cordata.