Assessment of fire hazard in Southwestern Amazon

Abstract

Fires are among the main drivers of forest degradation in Amazonia, causing multiple socioeconomic and environmental damages. Although human-ignited sources account for most of the fire events in Amazonia, extended droughts may magnify their occurrence and propagation. The southwestern Amazonia, a transnational region shared by Brazil, Peru, and Bolivia and known as the MAP region, has been articulating coordinated actions to prevent disasters, including fire, to reduce their negative impacts. Therefore, to understand the fire patterns in the MAP region, we investigated their main drivers and the changes in the suitability of fire occurrence for the years 2005, 2010, 2016, and 2020. We used a maximum entropy (MaxEnt) model approach based on active fire data from satellites, climatic data, and land use and land cover mapping to spatially quantify the suitability of fire occurrence and its drivers. We used the year 2015 to calibrate the models. For climatic data and active fire count, we only considered grid cells with active fire count over the third quartile. All our models had a satisfactory performance, with values of the area under the curve (AUC) above 0.75 and p < 0.05. Additionally, all models showed sensitivity rates higher than 0.8 and false positive rates below 0.25. We estimated that, on average, 38.5% of the study region had suitable conditions for fire occurrence during the study period. Most of the fire-prone areas belong to Acre, representing approximately 74% of the entire MAP region. The percentage of deforested areas, productive lands, forest edges, and high temperatures were the main drivers of fire occurrence in southwestern Amazonia, indicating the high vulnerability of fragmented landscapes extreme climatic conditions to fire occurrence. We observed that the modeling approach based on Maxint is useful for useful for evaluating the implications of climatic and anthropogenic variables on fire distribution. Furthermore, because the model can be easily employed to predict suitable and non-suitable locations for fire occurrence, it can to prevent potential impacts associated with large-scale wildfire in the future at regional levels.

The Consequences of Climate Change in the Brazilian Western Amazon: A New Proposal for a Fire Risk Model in Rio Branco, Acre

“…The fire foci found in Rio Branco were concentrated in September, during the dry season, a result similar to that observed in similar studies carried out in the same region [23,26,36]. The results also showed that the land use most susceptible to fire was the lowland dense ombrophilous forest, a result similar to that found by [23].…”

“…The kernel density is a methodology that provides greater reliability for analyzing fire behavior, as it transforms fire foci (points) into surface data [38]. In this aspect, our results showed a higher concentration of fire foci in Rio Branco during the dry season, following the pattern found by other studies [23,36,37].…”

Forest Degradation in the Southwest Brazilian Amazon: Impact on Tree Species of Economic Interest and Traditional Use

“…In Acre in the extreme southwest of the Brazilian Amazon, forest fires have already affected more than 500,000 ha of forests over the last 30 years, causing significant socioeconomic and environmental damage, including impacting tree species used by humans [18][19][20][21]. The increase in forest fires compromises Amazonian biodiversity, including species with high value to humans for timber and non-timber forest products, because few forest species are able to tolerate thermal stress, with most being poorly adapted to burning events [4].…”

Forest Fire Spread Hazard and Landscape Pattern Characteristics in the Mountainous District, Beijing

“…The forest fire spread hazard refers to the possibility of a forest fire spreading (assuming that a forest fire has already begun) [1][2][3][4][5][6]. Under the influence of climate change and land use changes, the occurrence probability and intensity of extreme fires have increased significantly [7][8][9][10][11][12][13]. Under the combined action of flammable vegetation types, special dangerous terrains, and harsh meteorological conditions, the probability of forest fires spreading rapidly and out of control has increased significantly, seriously threatening forest resources and the habitats of wild animals and plants, as well as life and property security and homeland ecological security [14][15][16][17][18].…”