Tropical forests are highly diverse ecosystems with significant carbon sequestration potential. Above-ground biomass (AGB) represents a key carbon pool in these forests. We estimated AGB along with diversity, structural, and environmental attributes, from eight one-hectare permanent plots in the tropical forests of the Western Ghats, India. The relationships between these attributes and biomass were assessed. Shannon diversity (Pearson's r = 0.63), mean diameter at breast height (DBH) (r = 0.99), and total basal area (r = 0.76) showed positive correlations with AGB. The AGB value ranged between 228.6 and 746.8 Mg/ha, while species richness varied between 47 and 95 ha−1. Large woody plants (DBH ≥ 60 cm) had the highest contribution (5.9–62.13 %) to AGB despite their low prevalence (0.18–3.14 %). AGB also showed strong positive correlations with large tree definitions (r = 0.70 - 0.82), highlighting their crucial role in carbon storage. These findings highlight that conserving large trees and maintaining species diversity is critical for sustaining carbon stocks, underlining the need for targeted forest management strategies that enhance both biodiversity and climate mitigation outcomes.