Book excerpt: Tree based production systems abound especially in the tropics. Despite the pervasiveness of such multipurpose “trees-outside-forest” resources, they have not attracted adequate attention in the development paradigms of many nation states. These multispecies production systems impact the ecosystem processes favourably. Yet, our understanding of the diversity attributes and carbon dynamics under agroforestry is not adequate. This book focuses on the role of multispecies production systems involving tree and crop species as a means for carbon sequestration and thereby reduce atmospheric carbon dioxide levels. Sixteen chapters organized into three broad sections titled: Measurement and Estimation, Agrobiodiversity and Tree Management, and Policy and Socioeconomic Aspects represent a cross section of the opportunities and challenges in current research and emerging issues in harnessing carbon sequestration potential of agroforestry systems.