Queimas controladas em àrea de Eucalyptus urograndis (Clone H13) na região de transição Cerrado-Amazônia de Mato Grosso

Abstract

This study aimed to analyze the behavior of the fire in controlled fires in plantations of Eucalyptus urograndis (Clone H13) that were 4.5 years old in the city of Sorriso-MT, and to compare the results of the test with simulations of two computer programs, the BehavePlus and the Eucalyptus Fire Safety System (EFSS). It was evaluated the conditions of distribution in the plantation field: Eucalyptus-forest interface (EF), eucalyptus-crop interface (EL) and the center of the plantation field (EE) for 5 months (from May to September). The fires were carried out in areas of 3 x 20 m, they were measured: the progression time of the fire, the flame length and weather variation. The surface combustible material was sampled before and after the burning in an area of 1 m2, with four replications per area and characterized according to Rothermel (1972). The position EF presented greater amounts of combustible material (16.09 t.ha-1

) and longer duration of fire (57.6 min), lower values of the fire propagation (0.37 m min-1), flame length (0.67 m), intensity of the fire line (200.4 kW.m-1 ) and combustible material consumed (92.7%). The EL positions and EE had similar influences in the variables that describe the fire behavior. August and September showed the largest amounts of combustible material, propagation speed, flame length, result of lower relative humidity and the fire duration. The EL position and the months of July and September showed the most significant values in both simulated software. The BehavePlus overestimated the simulated values, while the EFSS showed the best performance in the simulations. Based on the fire behavior and the simulations it was concluded that the implementation of controlled fires should be carried out in July and it is better to adopt the following sequence positions: EF, EE and EL.