ANÁLISE ESPAÇO-TEMPORAL DOS FOCOS DE INCÊNDIOS E SEU EFEITO NAS QUEIMADAS NO ESTADO DO RIO GRANDE DO NORTE

Abstract

In the semi-arid region, the combination of seasonal rainfall patterns and the deciduous strategy of caatinga vegetation creates conditions for forest fires, particularly during the annual dry season, which is exacerbated by prolonged periods of periodic droughts. Thus, given the semi-arid climatic conditions in Rio Grande do Norte, particularly in Western Potiguar, and the peculiarities of caatinga vegetation, especially during the dry season, studies on the historical occurrence of forest fires in the state and the recovery capacity of caatinga vegetation in Western Potiguar are justified. Fires can be detected using satellite data as heat spots on the Earth's surface. Moreover, the affected areas exhibit a specific spectral response that can be monitored using remote sensing data. Therefore, this project aimed to perform a spatio-temporal historical analysis of fire outbreaks in Rio Grande do Norte, as well as to analyze the recovery of caatinga vegetation from the effects of fires in Western Potiguar using Burned Area Indices (NBR and ΔNBR) and the Soil-Adjusted Vegetation Index (SAVI), applied within a Geographic Information System (GIS) environment. The spatio-temporal series of fire outbreaks in Rio Grande do Norte was analyzed using data from the Queimadas Program (INPE) and Global Forest Watch (GFW) for the periods 1998-2021 from INPE and 2012-2021 from GFW. SENTINEL-2A (S2-MSI) satellite images were used to apply the NBR and ΔNBR indices for fire outbreak areas (dates of major fires in parentheses): Apodi (01/04/2021), Alexandria (09/23/2020), and Patu (09/19/2019). The images correspond to dates shortly after the fires and one year after the events. The areas with the highest concentration of fire outbreaks are Western Potiguar and the Eastern Coast, with greater frequency from August to January, the seasonal dry period in the semi-arid region, with the municipalities of Mossoró, Serra do Mel, and Pau dos Ferros standing out from 2018 to 2021, mainly in agricultural areas. The most severe fire areas were 781 ha in Apodi, 120 ha in Alexandria, and 141 ha in Patu. The fire-affected areas that showed recovery (low and high) one year later were 46.22% in Apodi, 66.89% in Alexandria, and 86.51% in Patu, with the latter municipality showing a high recovery rate of vegetation. Thus, it is inferred that the recovery of caatinga vegetation from a major fire is possible, provided there are no new disturbances in the area. Forest fires and wildfires in Rio Grande do Norte are strongly linked to anthropogenic activities, as the concentration of fire outbreaks occurs in regions of the state with a tradition of agricultural activities, such as Western Potiguar, or areas of dense human occupation, with the expansion of real estate developments and the sugarcane industry, as seen on the Eastern Coast in the Natal region.