The Sirente Velino group forms a sort of belt used by the wildlife to go from one side to the other of the Apennines. It has a strategic topographical importance, because it represents a necessary connection between the mountains of Reatino, northern Simbruini, the area of Abruzzo, Lazio and Molise National Park (in the south-east) and Gran Sasso e Monti della Laga National Park in the north.

The two massifs show both similarities and differences for vegetation that is on their slopes and with reference to their origins. Even being separated by The Rocche Plateau, the two groups can be considered singly in reference to the same geological and tectonic origin.

The Velino Group is without spectacular vegetation and, with a predominance of semi-desert areas, while The Sirente chain (with the exception of some areas on the south and the peak) has extended formations of vegetation.

The Massif of Sirente

This Mountain, located in the central eastern portion of the Park, has the shape of a slope long about twenty kilometers oriented NO / SE from Rovere (1.413 m) to Forca Caruso Pass (1.107 m), and is characterized by the sequence of various peaks as hill of Mandra Murata (1.949 m), Macerola Peak (2.258 m), Mount Sirente (2.348 m) the highest peak, Mount Canale (2.207 m), Mount St. Nicola (2.012 m). The Celano Gorges and Arano Valley separate the less ridge of the Celano Sierra from the major one of Sirente.
Seen as a whole, the Sirente presents a divergence on its sides. The one exposed to SO has gentleness and slightly wavy with discontinuous rocky emergencies and degrades to the Fucino Plain. The NE side is of rocky nature with steep inconsistent faces, full of deep incisions; many of these, such as the Maiori canyon and Lupara Valley, have been determined by the last pleistocenica ice glaciation that interested the Velino, and the Sirente but marginally.
The geological nature of Sirente massif does not differ from that of Velino. In NE side emerge the Cretaceous organogenic limestones which were subsequently shaped in part by quaternary glacialism. The SO side sweet and grassy, exposes marble-calcareous formations. Spread throughout the massif the karst phenomenon that occur with traditional epigeous forms as dolines, karrens, poljes (for example, The Pezza Plains) and with those hypogeal as caves, meatus, swallow-holes.

The Massif of Velino

The Velino massif, located in the western part of the Park, is one of the most impressive and extensive of The Central Apennine. The tormented and complex orographic structure that distinguishes it, determines a wide variety of microclimates and environments: it is a biological wealth of great importance, with a twenty distinct plant communities, included in the four altitude bands that follow each other from the feet of the massif (m. 1.000 approximately), to its top (m. 2.486); in such area there are about 600 species of plants and 190 species of vertebrates, regularly included in the census.
From a minimum of 987 m. (Bocca of Teve), the Velino massif rises up to peaks that exceed 2.000 meters above sea level, such as Mount Velino (2.487 m), which is the third summit of Apennine, Mount Cafornia (2.424 m), Mount Sevice (2.331 m), Mount Rozza (2.064 m).
The geological nature of the massif is characterized by Cretaceous organogenic limestones, compact and very permeable, only in some high altitude plateaus are constituted of marly formations, less permeable and with faster pedogenesi.
The Velino gives the opportunity to observe a wide range of geomorphological phenomenon. Imposing manifestations of quaternary glacialism are those of the Maielama Valley and Teve Valley, two major glacial valleys with U section, long up to 5 km and deeply collected between high precipice walls. They have frequent signs left by glaciers that have formed: glacial thresholds, moraine accumulations, erratic boulders, rocks, suspended valleys (among which the largest is the Genzana Valley which flows in the Maielama Valley).