Forests in developing countries have the potential to contribute to global efforts to mitigate climate change, promote biodiversity and support the livelihoods of rural, local people. Approximately one-fourth of such forests are under the control of local communities, which primarily manage forests for subsistence and to meet their livelihood needs. The trend of bottom-up community control is increasing through the adoption of decentralization reforms over the last 40 years. In contrast, the United Nations has introduced the top-down program, Reducing Emissions from Deforestation and Forest Degradation (REDD+) for the conservation and enhancement of forest carbon and the sustainable management of forest in developing countries. REDD+ incentivizes forest-managing communities to sequester carbon and reduce emissions. REDD+ has created hope for managing forests to mitigate climate change and has created fear that the new initiative may not be effective and may not ensure continuing forest-managing community benefits. However, little research has been conducted to answer these concerns. By taking nationally representative data from Nepalese community-managed forests (“forest commons"), I bring insights into whether and how these forests can contribute to REDD+ initiatives, particularly as they relate to carbon sequestration, biodiversity, equity in benefit sharing and collective action. My results indicated the highly variable carbon and biodiversity in the forest plots across the country, depicting the availability of space for additional growth in carbon storage and biodiversity conservation. My results also reflect the complex and varied relationships of carbon with different indices of biodiversity at the national level, across geographic and topographic regions, and in forests with varying canopy covers. Weak positive relationships between carbon sequestration and biodiversity conservation indicate the possibility of synergies between carbon-forestry and biodiversity conservation. I also found that the formal community forestry program (CFP) has clearly positive impacts on biodiversity conservation and household-level equity in benefit sharing and a negative impact on carbon sequestration at the national level. However, disaggregated results of impacts of CFP on biodiversity, carbon and equity across geography, topography, forest quality and social groups display mixed results i.e., either positive or negative or neutral. I also identified that different drivers of collective action have different (i.e., positive, neutral, and negative) associations with carbon sequestration, which either supports or challenges established knowledge. In aggregate, my research indicates the potential of contribution by forest commons, and specially the CFP, to global environmental initiatives such as REDD+. It suggests that targeted, dedicated policies and programs to increase carbon sequestration, biodiversity conservation and foster equity and collective actions are critical. In addition, my results also contribute to the growing literature on socio-ecological implications of forest commons that demonstrated the need of interdisciplinary research to understand human-nature relationships in the changing context.