Conservation status of the Natura 2000 Habitat Types is assessed through parameters that include the presence or absence of Typical Species. The EEC and the Greek application guidance documents do not mention a clear definition of «Typical Species» and most of the Habitat Types’ Typical Species lists published for the whole Greece have common species with others. Moreover, they can contain till 48 species without indication on which species is more typical than another for a Habitat type. Taking the example of oak forests habitat types, this paper exposes a method to find the Typical Species which are sufficiently linked with a Habitat Type to be exclusive. It also exposes the way to give ecological profiles for the Typical Species, and by that way to inform on habitat types ecology. This permitted to propose a list of maximum 8 ranked Typical Species for three Habitat Types and a new partial organization of the North Greece oak forest’s Natura 2000 Habitat Types.