Assessing above ground biomass and carbon stocks among vegetation types In the Borneo Tropical Rainforest

Above-ground biomass (AGB) is a fundamental indicator of ecosystem productivity and carbon storage, and plays an important role in climate change mitigation efforts. However, variability in species composition and structural characteristics remains a challenge in producing accurate biomass estimates in tropical forests. This study aims to quantify AGB and carbon storage potential in the dominant vegetation types of Kalimantan's tropical rainforests. We established 20 × 20 m sampling plots and estimated tree volume and biomass using species-specific allometric equations. Vegetation inventory identified rubber, teak, and oil palm as the dominant species, each showing different wood density and biomass expansion factor (BEF) values. Teak had the highest wood density (670 kg m⁻³) and carbon stock, while oil palm had the highest BEF (3.40), indicating a more uniform distribution of biomass. Total AGB reached 154,942.44 kg, equivalent to 72.82 tonnes of carbon and an annual sequestration potential of 801.05 tonnes of CO₂ equivalent. Carbon accumulation shows a strong correlation with species characteristics such as diameter at breast height (DBH), tree height, and form factor. These findings emphasise the importance of species-specific structural assessments in carbon accounting frameworks and carbon offset programmes in tropical forest landscapes. Further research is recommended to integrate below-ground biomass, long-term monitoring, and remote sensing to improve carbon estimates at the landscape scale.