Elevation and management-induced vegetation and soil carbon shift in Eastern Himalayan forests: Advancing nature-based sustainability solutions (NbS)

Tropical montane forests are essential carbon sinks that significantly contribute to climate regulation; however, their biomass and carbon dynamics remain underexplored in Indo-Burma biodiversity hotspot of the Eastern Himalaya. With this motive, we quantified tree diversity, above- and below-ground biomass, and soil organic carbon across five forest sites in Mizoram, Northeast India, encompassing three protected areas and two community-managed forests distributed along an elevational gradient (70–1900 m amsl). A total of 192 tree species, belonging to 132 genera and 65 families, were recorded, with higher tree richness and density in community forests. Total tree carbon stock ranged from 182.9 to 297.4 Mg C ha −1 and increased as a function of elevation, explaining 57 % of the variability in above-ground biomass. Sentinel-2–derived vegetation indices demonstrated strong correlations with field-measured biomass, particularly modified soil-adjusted indices such as MSAVI (R 2 = 0.71) and SAVI (R 2 = 0.70). A multivariate regression model integrating multiple indices achieved high predictive accuracy (R 2 = 0.87). High-elevation forests, such as Phawngpui National Park (PNP) and Hmuifang Community Forest (HCF), exhibited greater carbon storage, reflecting lower disturbance and favourable microclimatic conditions. Community-managed forests stored carbon amounts comparable to or exceeding those of protected areas, highlighting the effectiveness of participatory governance in the region. Integrating remote sensing with field-based data provides robust, scalable framework for monitoring carbon dynamics in mountainous regions. These findings emphasise that community forestry represents effective Nature-based Solutions (NbS) for enhancing carbon sequestration, strengthening ecosystem resilience, and advancing India's climate commitments under NDCs and REDD + frameworks. • Community forests store soil carbon comparable to protected forests. • Elevation strongly influences biomass and soil organic carbon stocks. • MSAVI and SAVI best predict aboveground biomass from Sentinel-2 data. • Integrated field–satellite model explains 87 % of carbon variability. • Community forestry enhances Nature-based climate mitigation potential.