Why are local people and state agencies in Kilwa, Tanzania resistant to cooperate in governing local forests despite over ten years of experimentation with participatory forest management in Tanzania? I apply a political ecology framework in analyzing and explaining how ecological and political (social, economic, cultural) changes have transformed the composition and roles of actors for collaborative forest governance focusing on local people, state agencies, civil society, international community and private sector. Preliminary field work was conducted between 2009 and 2010 to identify study sites, gather preliminary information on socio-economic, institutional and ecological conditions of people and forests in the district. Contemporary environmental challenges such as mitigating climate change through avoided deforestation in the tropics calls for multi-stakeholder collaboration at multiple levels. Communities in Kilwa started avoided deforestation projects beginning 2008 as part of the UN pilot program in 9 countries including Tanzania, to reduce emissions from deforestation and forest degradation (REDD), and my research makes timely contributions to achieving effective collaboration in implementing REDD projects. I apply a combination of ethnographic field work and ecological methods in understanding changes in political and ecological systems and their ramifications on collaborative forest governance. Analyzing factors for effective collaborative forest governance using political ecology framework is necessarily interdisciplinary and draws from concepts and methods in ecology, anthropology, economics, sociology and political science. My research contributes in advancing the theory and practice of political ecology by demonstrating usefulness of a balanced ecological-political focus in analyzing and explaining factors for effective collaborative environmental governance from local to global levels in addressing tropical deforestation in a changing climate.