The forest is mainly composed of spruce (60% of the surface area), fir and beech, but its stands are rich and varied. In fact, there are several habitats of Community (European) interest: subalpine blueberry spruce forest, subalpine tall-herb spruce forest, thermophilic limestone scree, mountain hay meadow, whose value has led to their inclusion in the NATURA 2000 network. In addition, part of the département's property is included within the perimeter of the Arrêté Prefectoral de Protection de Biotope du Site du Mont de Grange.
As a result, the site boasts a diverse fauna, including a number of protected heritage animals: bats, woodpeckers (importance of dead trees), lynx, amphibians, black grouse...

Every year, from May to October, the Département and its partners organize free nature discovery events, enabling you to discover the richness of the site in a fun, artistic and unusual way.

ENS owned by the Département de la Haute-Savoie