Monitoring Amazon Forests using LandTrendr and MapBiomas: A Case Study from Trincheira Bacajá, Pará (2018–2023)

Abstract. The growing pressure on the ecosystems of the Amazon Biorne highlights the need for continuous monitoring of vegetation cover, especially in sensitive areas such as Indigenous lands. This study aims to identify and analyze forest change trajectories in the municipality of São Félix do Xingu, with an emphasis on the Trincheira Bacajá Indigenous lands reservation during the period from 2018 to 2023. ln the analysis, two approaches were compared using Landsat historical series. The first one is the LandTrendr algorithm, which was applied on the Google Earth Engine platform. The second one is based on the yearly land cover maps of the MapBiomas project. The comparison between the methodologies showed that, although they differ in sensitivity and detection criteria, both identify consistent patterns of forest suppression areas in the region. LandTrendr enables a more detailed analysis, while the MapBiomas-based approach is more straightforward. The high spatial convergence of the results reinforces the importance of integrating multiple approaches for forest monitoring in Indigenous territories and land reform settlements, contributing to the support of public policies aimed at conservation and environmental protection.