The institutional arrangements and return on investing in climatic change mitigation require international economics and management of the networks actors involved in the sector. As trees remove carbon dioxide from the atmosphere (carbon sink), planting trees is one of carbon sink economic management of green economy. Planting trees not only seize carbon but also gives tree planters other economic benefits for current and future generation. The smallholder farmers in Karagwe district have been receiving carbon credits from Green Choice Company (Green Choice , 2019) to plant trees for a decade through Green for Education and Poverty Alleviation Trust (GEPAT, 2019) which organizes the smallholder farmers who are carbon credit receivers. receive carbon credit funds from the carbon credit provider (Green Choice). Green Choice give They receives carbon credit through Wakk Foundation through GEPAT. In this case Green Choice company is the buyer of carbon dioxide. Green Choice and other buyers of carbon credit buy tons of emitted carbon dioxide equivalence (tCO2e) in terms of supporting farmers in Karagwe district to invest in tree planting. This is a current green investment model succeeded to plant more than 1,500,000 trees annually with expectation of reaping more return among the current and future generations. However, reaping high returns, requires current investment supported by good economic and management strategies. GEPAT participatory action research, as a case, demonstrates in its findings the economic organization, management and networking structure needed to manage climatic change investments. The Economic and management of the networks of green investment actors has revealed a high return on investment in Karagwe district in terms of climatic change resilience in terms of the lowered temperatures in the area relatively compared to the previous periods. Similarly, the number of planted trees has resulted into high returns measured in terms of carbon dioxide equivalent removed from the atmosphere by GEPAT members through a forestation (carbon sink) at low transaction costs. Mixed research methodology (triangulation) methods including qualitative and quantitative research methods have been used to address the phenomenon. The major research designs used are explorative, descriptive, and explanatory have been used in this case study. This new network of green business alliance taking place among the carbon credit providers and carbon trade markets. The investment return of tree planting has been articulated in this paper and recommended for sustainable economic development is discussed.