The Sierra of the Culebra is showed as a space with deep transformations in its physiognomy vegetal during a long temporal evolution. The agent which caused these changes has been the human being, who, of direct or indirect way, has eliminated the forest species, or has let the replace of same forest species by others, creating so a medium of high stability of the vegetation. Here is studyed the result of this dinamic of the vegetation in two significant moments of the evolution, the 18th and the 20th centuries. In the first date we already have found a lanscape vegetal broadly modelling by the man, with predominance of the brushwoods of heather, across of the introduction of a determined economic structure. While in the second hand of 20th century will be external agents to the highland space, which force a new dinamic with the introdution of new forest species, the conifers, until this moment foregin to the historic process of the Sierra. This new orientation which is given in relation to a economic different structure, which had been put in practice traditionally in the zone.