Atlantic and medio-European forests of Fraxinus excelsior, Acer pseudoplatanus, A. platanoides, Ulmus glabra, Tilia platyphyllos, Fagus sylvatica, Quercus robur, on unstable scree or colluvions of abrupt, shady and humid slopes, with abundant ferns, characterized by Asplenium scolopendrium and the ecological group of Actaea spicata, Lunaria rediviva and Helleborus viridis.