Fire is a common feature of the cerrados, as it is for most savanna ecosystems. Fires set by man or lightning are common and have been for thousands of years. Vicentini (1993), in a paleoclimatic and paleovegetational study, has registered the occurrence of fire 32,400 Years Before Present (YBP) in the region of Cromínia (GO); De Oliveira (1992) registered the presence of charcoal particles dated from 13,700 YBP in lake sediments in cerrado of the southeastern Brazil; and Coutinho (1981) has reported the occurrence of charcoal pieces dated from 8,600 YBP from a campo cerrado soil horizon lying at 2m depth. Although Gidon and Delibrias (1986) date the presence of man in Brazil to 32,000 YBP, according to Prous (1992) and Cooke (1998) there is no evidence of human presence in central Brazil before 12,000–11,000 YBP. Therefore, the particles of charcoal and burned wood dated from 11,000 YBP could, at least in part, be caused by the early inhabitants of the cerrado region (Salgado-Laboriau and Vicentini 1994). The indigenous people of the cerrado region used fire for hunting, stimulation of fruit production, control of undesirable species, and tribal war (Coutinho 1990a; Mistry 1998). Nowadays, the principal cause of fire in the cerrado is agricultural, its purpose either to transform cerrado into crop fields or to manage natural (more open cerrado forms or planted pasture (Coutinho 1990a; see chapter 5). Although fire is considered one of the determinants of the cerrado vegetation, the rapid occupation of the cerrado region has changed the natural fire regime (season and frequency of burning) with consequences for the vegetation structure and composition. In this chapter we present a review of cerrado fire ecology, with emphasis on fuel dynamics, fire behavior, nutrient fluxes, and changes in the structure and composition of the vegetation. A review of fire effects on population dynamics of woody plants is presented in chapter 9. |