One to three metre-tall brush of the Corsican endemic Alnus viridis ssp. suaveolens, sometimes accompanied by a few Sorbus aucuparia, Acer pseudoplatanus or Rhamnus alpina, limited to the moist, cool, north-facing slopes (ubacs) and, locally, to humid torrent galleries on the south-facing slopes (adrets) of the sub-alpine (1600-2100 m) belt of Corsica.