The urgent need to address climate change and biodiversity loss has intensified the focus on forest conservation and restoration. Nature-based solutions are proposed to mitigate climate change emissions and ambitious targets for expanding protected areas are set. These policies often target rural tropical landscapes due to their high biodiversity and carbon sequestration potential. However, these landscapes are also significantly inhabited, with an estimated 1.8 billion people living on lands crucial for biodiversity goals. These human-dominated forest landscapes are vital for rural livelihoods, income, and well-being, playing a crucial role in climate change adaptation. Understanding the relationships between carbon sequestration, biodiversity conservation, and rural livelihoods is crucial for identifying effective interventions that support rural well-being while achieving climate and biodiversity goals. While researchers and policymakers recognize the importance of considering multiple objectives and their interactions, many global analyses focus on single outcome domains, potentially neglecting co-benefits and overlooking unintended trade-offs. The relationship between livelihood benefits and other socioeconomic outcomes remains less understood than the links between carbon and biodiversity. Despite efforts to identify conservation and restoration opportunities globally, analyses of institutional mechanisms supporting co-benefits at subnational scales remain rare. This study addresses this gap by analyzing a unique dataset of forest commons, examining the interplay of carbon, biodiversity, and livelihoods under different governance structures.

Existing literature highlights the importance of considering multiple human and environmental objectives in forest management, emphasizing the need to understand the interactions, trade-offs, and synergies between them. However, many studies focus on specific outcome domains, potentially leading to unintended consequences. The relationship between livelihood benefits and other socioeconomic outcomes remains less well understood than the link between carbon and biodiversity. Studies on institutional mechanisms supporting co-benefits, particularly at subnational scales, are scarce. While some research emphasizes the importance of local participation in forest restoration, analyses of specific institutional features that enhance the positive effects of participation are limited. There is a growing body of work that highlights the risks and limitations of tree planting as a primary means for forest restoration, emphasizing the need for locally responsive and socially sustainable approaches.

This study uses a unique dataset of 314 forest commons in human-dominated landscapes across 15 tropical countries from the International Forestry Resources and Institutions (IFRI) research program. The data includes detailed information on local institutions and forestry interventions, allowing for analysis of governance factors associated with different forest outcome combinations. Three key benefits were examined: contributions to local livelihoods (measured using a factor analysis of firewood, fodder, and timber supplied by the forest), biomass (as a proxy for carbon storage, estimated using basal area), and biodiversity (measured as tree species richness using the Chao1 index). Three key governance factors were considered: the presence of a formal community forest management association, local participation in rule-making, and tree plantation interventions. The interrelationship of these three benefits was examined using hierarchical cluster analysis to identify synergies and trade-offs. Multinomial logistic regression was used to analyze the relationship between the governance factors and cluster membership, assessing the marginal effects and relative risk ratios of achieving different outcome clusters compared to a degraded forest cluster.

Hierarchical cluster analysis revealed five distinct clusters of forest commons: sustainable forests (high biomass, biodiversity, and livelihoods); carbon forests (high biomass, average livelihoods, low biodiversity); conservation forests (average to high biomass and biodiversity, low livelihoods); subsistence forests (high livelihoods, low biomass and biodiversity); and degraded forests (low in all three). Multivariate analysis of variance showed significant differences between clusters. Analysis of the governance factors revealed mixed results when examining their association with individual outcomes. However, the cluster analysis highlighted the importance of empowered local governance. The presence of a formal community forest management association and local participation in rule-making were consistently associated with a higher probability of forests belonging to the sustainable, carbon, or subsistence clusters and a lower probability of belonging to the conservation or degraded clusters. Tree plantations were positively associated with sustainable and subsistence forests but negatively associated with carbon and conservation forests. Compared to degraded forests, community management associations significantly increased the odds of forests being sustainable, carbon, or subsistence forests. Local participation in rule-making increased the odds of forests being carbon or subsistence forests. Conversely, tree plantations decreased the odds of forests being carbon or conservation forests.

The findings demonstrate that forests used and managed by indigenous and rural communities often support global environmental objectives alongside rural livelihood needs. However, trade-offs are common, highlighting the need to move beyond expectations of 'win-win' outcomes. The study's approach, using cluster analysis of multiple forest benefits, provides insights into the relationships among conflicts, co-benefits, and drivers of different benefit combinations. The strong association between empowered local governance and multiple positive outcomes aligns with research on local actors' comparative advantage in coordinating local governance. Formalized institutions can promote more effective governance, ensuring local autonomy, facilitating access to support, and improving accountability. The results challenge some general forest policy prescriptions, such as the focus on tree planting as a primary means for forest restoration. The findings suggest that institutional reforms supporting effective local resource management may be a more impactful policy strategy for achieving multiple human and environmental outcomes.

Empowered local governance, manifested through formal community forest management organizations and local participation in rule-making, is a key predictor of multiple positive outcomes in forest commons, supporting carbon sequestration, biodiversity, and rural livelihoods. The study highlights the need to move beyond project-based participatory approaches to build durable and empowered local institutions for long-term socioecological benefits. Further research should explore the diverse forms of local forest institutions and how national and subnational policies influence their success in achieving just climate action and forest restoration goals.

The study's dataset, while extensive, does not constitute a random sample, limiting the generalizability of the findings. Selection bias could potentially affect the results. The study's focus on tree species richness as a proxy for biodiversity might not fully capture the complexity of biodiversity. The associations found are not necessarily causal; further research is needed to establish causality.