Fire protection gradually changes the density of woody plants in numerous savannas around the world. In this study changes of structure in two tropical savanna areas with contrasting history of fire protection in the central Brazilian Cerrado is documented.
Vegetation was sampled with line intercept transects in two adjacent sites in Brasilia, Federal District. These transects were located within a nature reserve protected from fire since 1972 and within an adjacent reserve area that burns every 2 years.
Five savanna physiognomies, from a low forest (‘cerradão’) to an open savanna (‘campo sujo’), were sampled in both sites.
Fire protection increased the abundance of woody plants and favoured fire-sensitive species. With some exceptions, shrubs tended to be less affected by fire than trees. Species distribution was affected by a complex interaction of fire and physiognomy. Fire had the strongest effect on ‘campo sujo’ savanna, and a less significant effect on the intermediate physiognomies.
Protection permits the establishment of fire sensitive species. A long enough protection against fire could lead to the appearance of more wooded physiognomies in the Cerrado.