The Santissima Trinità Forest Nature Reserve, located in the municipality of Santa Fiora, covers a 37-hectare area along the upper Fiora valley. This expanse extends across to the western slopes of Monte Calvo and is characterized by an ancient European silver fir forest, a species endemic to the Appennine mountain range.
The relatively small stretch of European silver fir forest between altitudes of 600 to 720 metres has been recorded in the area since antiquity. Still in excellent condition, the evergreen silver firs are distinguished by their great size and slim, columnar profile. The forest’s undergrowth is populated by butcher’s broom and holly, while common horsetail, European spindle, common dogwood and basket willow grow in the more humid and wetter areas. At its southernmost distribution, the European silver fir forest opens up to a mix of tree species including linden, beech, hornbeam, maple, chestnut, oak, ash, elm and hazelnut.
Both the reserve and the surrounding area offer the opportunity to observe a diversified ornithological community including a number of birds of prey, notably the short-toed eagle, European honey buzzard, sparrowhawk, common buzzard and the hobby. The richness and integrity of the ecosystems within the reserve allows for the presence of forest birds of prey and other native species, like any other open territory. The nature reserve also features a small lake, thought to have been the location for the introduction of trout to aid the repopulation of the Fiora river.
The Franciscan Convent of the Santissima Trinità is located inside the nature reserve. Noted for its historical significance, according to popular legend, the convent was built in memory of Count Guido Sforza who, in the year 1400, killed a dragon that had been terrorizing the locals. Cutting its head in two, one half of the head was sent to the pope while the other half remained at the convent. The religious stance of the resident population is based on this origin story and is perpetuated by the convent; the sanctuary is renowned all the way to Maremma. A pilgrimage on foot starts from the convent. During the Middle Ages, nobility would bestow gifts to ensure the salvation of their souls. The reserve also features the fountain, Fontana del Papa, located near the convent.