Uso de geotecnologia para detecção e análise de queimadas e focos de calor em unidades de conservação no norte de Minas Gerais

Abstract

This research work is related to the use of geotechnologies for exploratory analysis of fires and validation of the heat focus monitoring system in conservation units of Northern Minas Gerais. Thus, this study aims to contribute towards the understanding of how fires occur, how they are distributed in space and the technical limitations of the orbital monitoring system. So, the following questions were intended to be answered: (1) what the most critical conservation units as regards fires? (2) What the most harmed plant physiognomy? (3) There is a standard in the space distribution of fires? (4) What is the frequency of those in the different size classes? (5) What the technical limitations of orbital monitoring system as to the detection and localization of heat focuses? Before those inquiries, this work was structured into three chapters. Chapter 1 brings a short theoretical referential which works as a basis for the understanding of concepts approached in the subsequent chapters. In chapter 2, the four first above cited questions were exploited and at last, chapter 3 approaches the limitations of the orbital monitoring systems of fires. The results obtained in chapters 2 and 3 show the potential of geotechnology tools in the analyses proposed by this dissertation. Through these tools, one could map and quantify the fires, which made it possible to ascertain the questions approached in this work. In the analyses proposed by chapter 2, it was found that the conservation units belonging to the category Environmental Protection Areas, these are the areas where fires occur the most due to the characteristics of large territorial extent and for allowing agricultural activities. In these areas, a policy of rural extension advising the farmer about alternatives of soil use and the adequate use of controlled fire, when the environmental legislation allows. It was also that the most harmed native vegetation was the Cerrado Stricto Sensu, the most abundant vegetation in the area. Nevertheless, one should take into account also the Veredas, physiognomy of poor resilience to fire and of great ecological relevance. Concerning the size of the fires, it was verified that most of the fires averages from 10.01 to 100 ha. The largest fires, in spite of less frequent, when summed together, stand for an increased area reached by the fires, which stresses the need to maintain the fires in the classes of smallest sizes. Further in chapter 2, clustered standards were detected in spatial distribution of fires, which suggests a more brief investigation on the possible socioenvironmenatal interactions which support these groupings. But in chapter 3, in the range of the validation of the monitoring system of heat focus, as it was seen to comer, the smaller the fire the smaller the chances to be detected, nevertheless, fires smaller than 100 ha were detected, a dimension which represents a pixel of the images of the MODIS and NOAA images sensors (at nadir). Cases of omissions of large fires were also ascertained, suggesting an investigation for possible improvements in the detection system. It is hoped that the results generated by those analyses lend themselves as supports to the understanding of how and where the fires occur and also for the technologic advancement of the orbital monitoring system of fires.