Tropical forests play a significant role in sequestrating and storing atmospheric carbon di-oxide (CO2) emissions. However, estimation of forest carbon (C) stocks in relation to changes in forest structure and disturbances are less studied. We estimated forest C stocks in live trees, saplings, lianas, deadwood, forest floor, and soil in Sitapahar natural forest reserve of Bangladesh based on field measurements and laboratory assessments. We categorized the 99 temporary sample plots into three canopy densities: closed, moderately closed, and open. According to the results, the forest C stocks were dominated by the soil C pool and forest C stocks in the closed canopy (91 Mg ha- 1) differed significantly from that in the open canopy (50 Mg ha-1). Forest C stocks were also affected by basal area (BA) and deadwood C stocks. In the open canopy, the second highest contributor to forest C stock was deadwood, whereas it was above and below-ground live biomass in the closed and moderately closed canopies. In the open canopy, forest disturbances significantly decreased height and BA, and C stocks in live biomass were significantly lower compared to the other two canopy densities. In the open canopy, decreased tree density resulted in the lowest C stock in litterfall and humus, and they were up to 95% lower compared to the other two canopy densities. C stocks in humus were higher than those in litterfall in the closed and moderately closed canopies, which was opposite to that in the open canopy. The soil C stock decreased with soil depth and the highest C stocks across all depths were in the closed canopy, followed by the moderately closed and open canopy. This study also provided a stand-level estimation of C stocks that contribute to determining which tree species sequester more carbon, such as Swintonia floribunda, Lannea coromandelica, Anacardiaceae and Moraceae.