Agroforestry is rapidly being transformed from an empirical, largely anecdotal collection of beliefs and practices into an emerging science in the field of natural resource management. Due to rapid growth in population, demand for wood and other forest products is increasing. The state of forest in this country is thus, insufficient to meet the timber and fire–wood requirements for growing population of the country. In the domestic production of forest products, these requirements are met through agroforestry, which refers to the plantation of forest trees on agriculture land. Agroforestry is the collective name for land use systems and technologies where woody perennials (trees, shrubs, bamboos, etc.) are deliberately used on the same land management unit as agricultural crops and/or animals, either in some form of spatial arrangement or temporal sequence (ICRAF, 2006). Tree cultivation for reasons like windbreaks, soil and water conservation had become a secondary objective of agroforestry growers, while the current primary objective of tree planting was for cash and investment. According to Gangadharappa et al., (2004), 37 percent of the agroforesty growers cut the trees in the age group of 20–30 years followed by 25 percent between 30–40 years and only 17 percent of farmers harvested above 40 years old trees. Further they revealed that 62 percent of the farmers sold their products through forest contractors, 27 percent through saw–mill owners and 11 percent directly to consumers. Marketing structure and channels of agroforestry products are totally different from other agricultural products due to bulkiness and high weight of wood and other forest products. In previous studies, no attempt had been made to study agroforestry marketing channels and margins earned by each intermediary. Therefore, detailed discussion on marketing of agroforestry products is also done in this book. This book is a major contribution towards this goal, and is aimed at students, research workers and practitioners in agroforestry and applied plant physiology. The authors have applied principles of plant ecology and crop physiology to develop more precise approaches that quantify biological (tree–crop) interactions in agroforestry systems. The various models developed, particularly the tree–crop interactions equation, provide practical but rigorous approaches for both above– and below–ground processes. This book also focuses on two basic resources: water and light. Tree–crop interactions for nutrients are not treated in depth as there are very few data on this subject.