The Sos Nibberos area covers a surface of approximately 7 hectares and has a buffer and renewal area of 350 hectares around it. It falls entirely within the Monte Pisanu State Forest.
A portion of the total surface is occupied solely by yews, the remaining part also by holly and some sporadic downy oak.
It was declared a "Natural Monument" with decree no. 24 of January 29, 1994, by the Department of Environmental Defense of the Sardinian Region pursuant to Regional Law no. 31/89.
It represents a plant formation of considerable scientific, historical-cultural and landscape importance populated by yews, almost millenary, which also reach a meter in diameter and heights of about 15 meters. The density is not excessive, yet it ensures considerable coverage, since the yew canopies are very expanded: in fact, in the points where the population is closed, the undergrowth is almost absent and completely lacks heliophilous species, while in the areas where the forest is more open, mesophilic vegetation is prevalent.
The soil that supports this formation is very evolved and, as the physical-chemical analyses confirm, very rich in organic substance and with intense biological activity.
Inside the area along the course of the stream there is a rare botanical endemism confined to this area, the Arrigoni bramble (Rubus Arrigoni Camarda) with characteristics very different from the common bramble (Rubus ulmifolius) such as, for example, a much larger leaf, tomentose and less spiny branches, a smaller infructescence with larger and less sweet individual fruits.
Due to its peculiarities, the area represents a unique population in Sardinia, whose naturalistic-vegetational, pedological and climatic characteristics are not renewable and therefore must be rigorously protected in the interest of all.
It is accessed from the Bonorva-Bono and Ittireddu-Bono provincial roads that join at the Foresta Burgos junction; after passing the access to the Monte Pisanu forest barracks, continuing towards Bono, take the dirt road "Ucca 'e Grile" where appropriate signs indicate the precise site.
For greater respect, it is suggested to proceed with the visit of the area on foot, leaving the cars in the parking lot and to use the specially equipped areas for any lunch breaks.
To visit the area, which is not easy to find, it is necessary to contact the Monte Pisanu Forestry Office.
