Use of fire has been recognized for a long time as a key innovation in the development of human groups, as a multisource technological improvement. Fuel wastes recovered from archeological sites are the direct evidence of the fire use in society economies of the past. In the process of production and use of fire, diverse parameters exist that intervene and influence in its development. In order to obtain data relative to vegetal composition from early to late Holocene and its exploitation by societies characterized by high residential mobility, we carried on an charcoal and wood analysis in archeological sites Cerro Casa de Piedra 7 (10,690 ± 120-3400 BP) and Cerro Casa de Piedra 5 (6780 ± 110-2805 ± 105 BP) (province of Santa Cruz, Argentina). The results obtained evidence a drastic reduction of taxa used as fuel among occupations corresponding to early Holocene and late Holocene. Throughout all the levels we verified the intense use of tree species for combustion, while bushes were also collected but in much lower overall percentages. Nothofagus pumilio is the species with the highest representation. These results allowed to identify acting modes that refer to acquisition strategies of woody material oriented toward on the collection of great caliber wood.