The saw-mill of Alós d’ Isil leads us to the world of wood and illustrates the way in which this important raw material has been used. From when it is cut in the forest right up to when it is transformed into planks ready for construction. The way it works using the supporting photographs help to understand the whole process, and shows us at the same time what was the exploitation of the forest and the use of forests: one of the complimentary economies of the Pallars Valleys, and one of the most characteristic forms of life of the Pyrenees.