The charcoal burning trade, an activity associated with thickly-wooded areas, is on the verge of extinction in the Pre-Pyrenean zone. The northern ranges of Aragon abound with quercus and acorn woods and through countless years the charcoal burners managed to take advantage of their natural resources. Charcoal in northern Aragon was mainly used by ironsmiths, and also for cooking and as fuel for gasification devices. When charcoal began to run short a group of charcoal burners would start looking for a cave or natural shelter in the area close to their work site. If no place fit to withstand the bad weather was found, they would build little huts called charcoal burners' cabins. These buildings had to be adapted to the environment, their shape and size varying according to the number of people they were to house, to the natural characteristics of the terrain and the availability of building materials. The most common types of huts measured about 8 square metres and were 1.6 metres in height. They were very well insulated from the cold and were made with slim tree trunks or some other local material, branches and big lumps of earth, following the same technique as that which was used to build the charcoal pits. They had to be placed close to the charcoal pits in order to monitor the delicate charcoal combustion process.
