Valle di San Martino develops on the southern slope of Vette di Feltre, drawing on their tough calcareous-dolomitic walls. The stream Stien and its small tributaries are fed by karstic springs draining part of the waters infiltrating in the plateau of the Vette. Among the most characteristic shapes of the landscape, the glacial valleys (Scalón) descending from the Vette, the gigantic boulders deposited at the end of the glaciations (Pian dei Violini), and the beautiful series of potholes in the upper stretch of the stream Stien. The vegetal landscape, mainly characterized by woodlands and woody cliffs, is dominated by mountain and submountain beech tree woods with Hop Hornbeam. The rocky environments are dominated by the Alpine Cinquefoil (Potentilla caulescens), often growing together with Spiraea hacquetii), an endemic species of Veneto-Friuli, with the famous Physoplexis comosa and, sometimes, with Primula tyrolensis, an important endemic species of the Dolomites. In the cool and narrow ravines of Stien it is possible to observe typically alpine species, like Ranunculus alpestris and Soldanella minima. The valley, isolated and quiet despite its proximity with the town of Feltre and its country hamlets, houses a rich alpine wildlife, that can be observed also at very low altitudes (Chamois, Golden Eagle, Black Woodpecker, Hazel Grouse...).