The Pigelleto Nature Reserve is divided between the provinces of Siena and Grosseto. It lies in the borough of Piancastagnaio, on the southern side of Mount Amiata. Founded by the Tuscan Region in 1996, the area of the reserve was one of the main mercury mining sites of Mounta Amiata and two disused mines can still be found within the reserve. The area is dominated by Poggio Pampagliano (969 m.) that together with Poggio La Roccaccia and Poggio Roccone, just slightly lower in altitude, form a curved ridge towards the north-east, that forms the watershed between the basin of the river Paglia and that of the river Fiora. The reserve protects a mixed wooded area, rich in plant species, among which the presence of silver firs as a spontaneous species is especially relevant. The Pigelleto wood is for the most part made up of tall trees, heir to the type of cutting carried out during the period of mining activity, that probably helped to maintain optimal spontaneous regeneration of the silver firs.