POST-FIRE RESPROUTING AND MORTALITY IN CERRADO WOODY PLANT SPECIES OVER A THREE-YEAR PERIOD

Abstract

The objective of this work was to evaluate resprouting features and mortality in Cerrado woody plants after annual controlled fires (in 1998, 1999 and 2000) in a campo sujo area (an open savanna physiognomy) of 2500 m2 at the Reserva Ecológica do IBGE, Brasília-DF, Brazil. The area was protected against fire for 23 years prior to the fires. All plants of the woody layer with diameter larger than 2.0 cm at 30 cm from soil level were tagged and identified. At about one year after each controlled fire the damage type and the number of basal and underground sprouts for each individual were recorded. Stem diameter and height were measured for each marked sprout. A total of 1307 sprouts were tagged and measured. The main impact of fire on resprouting was a decrease in the number of new sprouts after each controlled fire: 684 sprouts after the first burning to 248 after the third burning. Mortality of sprouts was 34.8% and 37.8% after the 1999 and 2000 fires. A decrease in the number of sprouts with a diameter smaller than 1.0 cm after the successive fires was also observed, indicating that fires at one-year intervals resulted in alterations in the structure of the woody vegetation in the area. The species mortality rates were higher after the first controlled fire. However, it seems that there is no relation between sprouting capacity and species survival. The species that show mortality rates lower than 10% also showed a variety of sprouting capacity.