Father of the Oaks Nature · Viana do Bolo, Viana, Ourense Image of Viana do Bolo, not of the place itself. A carballo of the species Quercus robur of exceptional size which gives its name to the oak grove where it grows; it is the most notable tree in a municipality dominated by chestnut groves, oak woods, birches and conifers. Photo: Estevoaei (CC BY-SA 4.0) What to see and do in Viana do Bolo