Community forests play a critical role in global carbon sequestration, acting as a carbon sink amid increasing urbanization. Despite their ecological significance, mid-hill forests of Nepal like Jamuna Dada Community Forest located in Kathmandu, remain understudied regarding carbon stock, species diversity and their interrelationship. This study assessed the carbon stock (CS) and species diversity (SD) in the Jamuna Dada Community Forest while deriving their relationship through field survey, statistical tests and regression. analysis. Twenty-seven circular plots covering 0.54 hectares were surveyed across the 108-hectare total forest area. Above-ground biomass was estimated using volume and wood density. Biomass was then converted to carbon stock using Biomass Expansion Factor (BEF) of 0.45. The carbon stock from the plots was then converted to total carbon stock of the forest. Species diversity was then quantified using Shannon-Weiner Index (H') and Simpson's Diversity Index (SDI) across the plots. An average carbon stock of 45.23 tonnes/ha, totaling 4,884.8 tonnes across the whole forest area was estimated. Species diversity varied significantly ( H' = 0 - 1.65 ; SDI = 0-0.814), with Syzygium cumini (high wood density) correlating with higher CS. Statistical like chi-square test ( x ^ 2 = 2.08 , p = 0.65 ), Fisher's exact test (p = 0.24) , ordinal logistic regression ( beta = - 0.18 . p > 0.05 ), and Spearman Correlation ( p = 0.152 , p = 0.45 ) showed no significant relationship between species diversity and carbon stock. These findings aligned with the mass ratio hypothesis, suggesting that functional traits of dominant species drive carbon storage rather than diversity alone. This study emphasizes the importance of species-specific management for optimizing carbon stock. These findings provide crucial baseline data for Jamuna Dada Community Forest and advocate for more integrated and science-based management practices.