ESTUDO DO COMPORTAMENTO DO FOGO EM UM TRECHO DE FLORESTA ESTACIONAL SEMIDECÍDUA NO MUNICÍPIO DE VIÇOSA, MINAS GERAIS

Abstract

The purpose of this study was to evaluate the fire behavior on a part of Semideciduous Seasonal Forest, using the variables: fire intensity, burning time, fuel, heat content and heat released. Ten plots of 5 by 5 meters were used , totalizing 250 m 2 , and the distance between each plot was 1 meter in a place named “Reserva da Biologia” property of Universidade Federal de Viçosa, Minas Gerais, (20º35’-28º50’S e 42º45’-43º00’W) . In this place a control burning was performed using strip headfire technique, obeying the slope direction. The amount of local dry matter, fire propagation velocity, intensity, heat released and heat content were measured. The time duration of the burning ranged between plots of 3’30 “to 9’18”. Wind velocity, temperature, relative humidity were constant in all plots, with values 3, 5 m s -1 North, 20º C and 79% respectively. The values found for fire behavior variables ranged between plots: from 0, 32 to 1, and 10 Kg m -2 for fuel, from 11, 94 to 75,79 Kcals -1 m -1 for burning intensity and from 1111 to 3789 Kcal m -2 for heat released. The average values for rate of spread and heat released were 0,017 m s -1 and 4411 Kcal Kg -1 , respectively. In the year 2005, the weather conditions were atypical comparing to another years in Viçosa, witch in every month occurs a certain amount of rain. This fact had interference in the fire behavior parameters, for that reason the burning were classified as low intensity .