Pemanfaatan Aplikasi Normalized Difference Vegetation Index pada Citra Sentinel-2A untuk Klasifikasi Kerapatan Tegakan Mangrove

Abstract

Mangrove ecosystems in Bontang City require effective and repeatable monitoring to support their long-term conservation and management. This study evaluated the performance of the Normalized Difference Vegetation Index (NDVI) and red-edge Normalized Difference Vegetation Index (NDVIre) derived from Sentinel-2A imagery for estimating mangrove stand density using field-measured basal area. Mangrove ecosystem boundaries were delineated using high-resolution imagery, resulting in an estimated area of 3,330 ha, with an overall classification accuracy of 94.44% and a kappa coefficient of 0.88. NDVI values ranged from 0 to 0.59, whereas NDVIre values ranged from 0 to 0.73. Both vegetation indices showed strong relationships with basal area; however, NDVIre demonstrated better model performance (r = 0.97; R² = 0.94; RMSE = 6.20 m²/ha) than NDVI (r = 0.95; R² = 0.91; RMSE = 8.28 m²/ha). The use of NDVIre reduced prediction error by approximately 25.1% relative to NDVI. These findings indicate that incorporating the Sentinel-2A red-edge band can complement conventional NDVI-based approaches and improve the estimation of mangrove stand density in Bontang City. Further validation across different mangrove conditions is required before broader spatial application of the model.