The holm oak wood represents one of the most widespread and characteristic forest formations of the Park territory. It is an association formed mainly by the Holm-oak (Quercus ilex), an evergreen oak more sensitive to low winter temperatures than other species of oak, and therefore widespread in regions with milder winters. In fact, the holm oak forest is widespread along the Italian coasts, in the Mediterranean areas, from sea level to the middle of the mountains, in areas characterized by temperate and humid winters and hot and dry summers.
In the territory of the Park, the holm oak forest is the type of forest where conditions of marked aridity are found; the holm oak is often associated with many other tree and shrub species (strawberry tree, phillyrea, mastic, terebinth, freckle, wild rose, alaterno, wild asparagus,) and lignous species, such as the robies, the smilax and ivy. In the shrub layer that characterizes the holm oak forest represented in the diorama there are two species of brooms, widely present, even in the particular rocky holm oak forests on the walls almost vertical facing south of the caldera of the Sum.