Lag De Pian Doss

The Lag de Pian Doss is a small mountain lake in the Val Mesolcina, the Italian-speaking valley in southern Graubünden, at about 1,650 metres above sea level, close to the village of San Bernardino. The valley runs south from the San Bernardino Pass toward Bellinzona, and the area around the pass is a landscape of spruce forest, meadows and wet ground, with the mountains of the Adula range to the north. Lag de Pian Doss is one of several small bodies of water in the district, and it is notable not so much for its size as for its nature: it is part of a raised bog, a type of wetland that is rare and valuable, and the area is protected as a bog of national importance.

A raised bog is a habitat that has formed slowly over thousands of years. It begins in a hollow where water collects, and peat moss, called Sphagnum, begins to grow and build up, layer upon layer. The moss holds water like a sponge and creates acidic, nutrient-poor conditions, and as the layers accumulate the surface rises into a low dome above the surrounding land, which is why it is called raised. The peat can reach several metres in depth, and it preserves plant remains and pollen, so bogs are archives of past climate and vegetation. Only specially adapted plants can live in such conditions, among them the insect-eating sundew, cotton grass with its white tufts, cranberry, bog rosemary and dwarf pines. Dragonflies and specialised butterflies also depend on this habitat.

In Switzerland, bogs were widely drained and cut for peat in earlier centuries, and only a small proportion of the original area survives. After a popular vote in 1987, the Swiss people approved a constitutional protection of bogs and bog landscapes of national importance, and since then the surviving sites have been listed in a federal inventory and protected from development. Lag de Pian Doss belongs to this group. Protection means that visitors must keep to marked paths, and not enter the bog itself, since trampling damages the fragile moss and the water balance, and dogs should be kept on a lead.

Reaching the lake involves a walk, since there is no road to its shore. The paths start near San Bernardino and climb gently through woods, and conditions are best from early summer to autumn. The surroundings are quiet and wild, and there are views of the surrounding peaks, with the tinkling of cowbells in summer. San Bernardino is a small mountain village known for its mineral springs, whose water is bottled, and for the pass road and tunnel that link Graubünden with Ticino. Other short walks and lakes, including Lago Moesola, can be combined with a visit.

Weather in the mountains changes quickly, and the paths may be wet or muddy, so wear waterproof boots, bring rain protection and check conditions with the local tourist office before you set out. The site suits walkers, botanists and anyone who enjoys quiet nature. Allow two to three hours for a walk.