Using Landsat Satellite Images to Detect Forest Cover Changes in the Northeast Region of Vietnam

Abstract

Globally and in Vietnam, forests are crucial resources for economic activity and for the survival of flora and fauna. However, deforestation in tropical regions continues to have negative effects on ecosystem services, climate regulation, and biodiversity protection. This study used Landsat 5-TM and Landsat 9-OLI/TIRS satellite imagery to investigate the changes in forest cover in Tuyen Quang province, located in the Northeast region of Vietnam, from 1992 to 2022. The maximum likelihood algorithm was employed to classify the forests in 1992, 2010, and 2022, with classification accuracy evaluated using the kappa coefficient for each year (0.890, 0.897, and 0.937, respectively). Additionally, the Normalized Difference Vegetation Index (NDVI) and the Soil Adjusted Vegetation Index (SAVI) were used to assess forest cover losses and gains, and their outcomes were compared with the results of the supervised classification. The findings indicated a significant decline in forest cover in Tuyen Quang province over the years. In 1992, the forest cover was estimated at 89.63% (5,259.33 km2) of the total land area, which decreased to 68.14% (3,998.61 km2) in 2010, and subsequently increased to 75.14% (4,409.09 km2) in 2022. The conversion of forested areas for agriculture often leads to a substantial reduction in forest coverage. Furthermore, logging and illegal land use conversion have significantly contributed to this problem. Although appropriate policies for forest management and conservation have been implemented in the research area from 2010 to 2022, a long-term plan is necessary to ensure sustainable land use and effective forest resource conservation and development in the future.