- Area: 177 hectares
- Altitude: 1'100-1'700 m a.s.l.
- Main species: white fir, spruce, beech and larch
- Year of institution: 1992
- Owners: Patriziato Generale d’Onsernone, Stato del Cantone Ticino
- From May-October, to the best of Sunday and August, when the Valle di Vergeletto quarries are closed.
- With heavy rains access to the Reserve is not recommended, with snow precluded. Attention: it is mandatory to follow the marked trails. Mountain equipment is necessary.
- The Forest Reserve of the Arena can be visited along the path that from Piano delle Cascine (1126 m), 5 km from Vergeletto, leads to the Alpe Arena (1689 m). From here you can go back on the same path, or add a ring, passing by Cruseta.
- Guided tours are available on request.
- PARKS AND GARDENS Natural parks