The plateau of the Giara (the locals call it Sa Jara) is located in the central part of Sardinia, to the west (W) of the Gulf of Oristano, between the Marmilla, the Trexenta, the Sarcidano and the Arborea. Since 1995 it is recognized as a SIC area (Site of Community Interest).
The Italian name Giara and the Sardinian name Jara are used in this part of the island to indicate some basaltic plateaus, but they are still common names in many regions of the Earth to indicate flat plains, often covered with lava, volcanic islets, stony areas, etc. .
The upper part of the plateau is located in a north-west-south-east direction (NW-SE) for a length of 12 km. It has an average height of about 550 meters, oscillating between the 609 meters of Zepparedda (SE) and the 490 meters of Corona Arrubia (NW) and an almost horizontal appearance (slightly inclined towards NW) consisting of a base of marls and sandstone on which rest several alternating layers of calcarenites and sandstones sedimented in the Miocene (20 million years ago); altogether it has an area of 45 square kilometers and a vaguely trapezoidal shape, with the maximum width to SE that gradually narrows towards the NW.
Over these layers of rock they created (about 2.7 million years ago) two cracks from which the basaltic lava that covered the entire plank emerged. The two eruptive cones are recognized in Zepparedda (SE - 609 m) and Zeppara Manna (NW - 580 m), among these is the fault of Sa Roja that crosses the plateau transversely, creating a step of about 30 meters. /> The border is affected by a landslide phenomenon that has created recesses in the vicinity of which are the only natural entrances to the plateau, the Scalas.
Above the basalt surface, over a period of millennia, a light layer of earth has been deposited, rarely over 50 cm deep, on which a particular vegetation with a distinctly Mediterranean character has developed. Covered originally by thick woods, the Giara today presents all the characteristic aspects of a typical anthropized Mediterranean area: this allows us to understand how man can influence the transformation-conservation of a territory by creating very different environments: woods, scrubland , garrigues, prairies, meadows.
The determining factors of this transformation were the fires, the cutting of the forest to the advantage of the cork oak, the excessive grazing and, in recent years, also the uncontrolled tourist fruition.
In spite of all the Giara still maintains a high degree of naturalness. b>
Among all the mammals living on the Giara, the Cavallino della Giara , Equus caballus giarae, is undoubtedly the best known.
Since there are no fossil finds of horses in Sardinia, it is thought that the horse was probably introduced during the Nuragic period or in the Punic period. In the Middle Ages entire herds lived on the island in the wild and some populated the island of Sant'Antioco until the end of the nineteenth century. The only place where these animals today live in the natural state is the plateau of the Giara. Characteristic for their small size, they are adapted to the particular environment of the Giara, with plenty of food and water during winter and spring and shortage of the same during summer and autumn.
During the winter and spring the natural depressions of the Giara, called Paulis, are filled with rainwater: the largest become large reserves and preserve the precious element until the summer. During the spring the approximately 60 Paulis of the Giara are covered with a mantle of white aquatic buttercups Ranunculus aquatilis: in this period, in the larger Paulis, it is easy to observe the Cavallini grazing peacefully, feeding on the buttercups they are fond of. During the summer some springs above the plateau ensure water for all the animals.
During the excursion it will be interesting to discover the practical use of some plants in crafts, food and folk medicine.
Even the man has shown to appreciate this hospitable place, leaving testimony of his attendance since the Neolithic (6000-2700 BC). There are numerous Domus de Janas (grotticelle with several rooms dug into the rock and used as burials) built on the slopes of the Giara. The remains of ceramics, flint and obsidian found above the plateau suggest the widespread occupation of the territory during this period.
A confirmation of life over the Giara occurs in the last phase of the Copper Age (2700-1800 BC) with the protonuraghe Bruncu de Madili, located on the edge of the plateau, at the extreme corner SE, above Gesturi, Barumini and Tuili. The imposing monument (dated to radiocarbon C14, 1820 ± 250 BC) is considered the most important in Sardinia for the study on the evolution of construction techniques of nuraghi. We recognize the entrance stairway and the remains of two circular rooms, originally covered by logs and branches. A few meters from the protonuraghe, still the subject of archaeological excavations, lies the village (end of the 2nd millennium BC), composed of several groups of circular huts arranged around central courtyards.
During the excursion to the Giara it is possible to observe some of these typical environments where many plant and animal species live.
But it is in the Nuraghic period that this natural table is transformed into an impregnable natural castle, fortified with over 23 nuraghi. Around the nuraghe lived small self-sufficient communities. The food was given by hunting, breeding, gathering and exchange with the communities that lived and farmed in the valleys below. A spring close to the nuraghe, just below the ridge, ensured water even in the driest seasons.
The ingenuity, the strength and the civilization of our ancestors manifested itself completely with the construction of a splendid fortress: Su Nuraxi of Barumini, administrative center of a "canton" that included the Giara and the valleys of a part of the Marmilla and Trexenta .
Su Nuraxi, and therefore Sa Jara, had to play a major role in the nuragic period in the control of the production of wheat in one of the most fertile areas of the island.
At the end of the 6th century the fortress of Barumini fell under the Carthaginians, who presumably also controlled the Giara.
Numerous is the surface material that has been found in almost all the Nuraghic buildings, above and around the plateau, but the only Punic settlement in the area is attested by the fortress on Monte Sant'Antine di Genoni, a conical relief covered with basalt detached from the Giara following ancient fractures.
In the Roman period the Giara assumed a relevant strategic importance: the Colonia Julia Augusta Uselis (near Usellus) and the center of Valentia (near Nuragus), two important road stations respectively to the west and east of the plateau testify.
The huge amount of material found around the plateau indicates a very high concentration of settlements, linked to agricultural exploitation: these small towns, which developed and then transformed into the current countries, became the main wheat suppliers of Roman Sardinia. >
Two important military centers are to be found above the plateau: Bruncu Suergiu di Genoni and Santa Luisa di Tuili, which seems to attest to an interesting phallic cult of the Imperial Age.
The Byzantine presence in this part of the island is testified by the remains of a chapel dedicated to San Costantino and Sant'Elena, located on the Monte S.Antine (S.Costantino, in fact) of Genoni.
In the judicial period the Giara is part of the Giudicato di Arborea and is included among the curatoria of Arborea, Valenza and Usellus.
The characteristic conical peak of Las Plassas still preserves the remains of the Castle of Marmilla, built by the Lords of Arborea to control the borders with the Giudicato of Cagliari. In addition to the Castle of Marmilla, around the Giara were built the Castle of Murgunulis in Usellus and the Castle of Funtana Menta in Senis, which guarded this part of the Giudicato. In this period (13th century) the interesting two-aisle Romanesque church dedicated to San Giovanni was built in Barumini.
Already since the judicial period the Giara does not seem to have hosted any permanent settlement: only the shepherds have frequented the plateau by building the typical "masonis" and "cuilis", which still today, together with the nuraghi, characterize the environment and the landscape of the Giara.