The Bragantina region is located in eastern Amazonia, Northern Brazil, covering around 9000 km and with a long history of agricultural activities. For over 150 years, human activities have modified the landscape and reduced the primary forest area to less than 5 % of the original cover (Hedden-Dunkhorst et al., 2004). Land use consists mainly of livestock grazing and cultivation of annual and perennial crops mixed with spontaneous forest vegetation in the fallow areas. During the past 40 years, the population has rapidly increased and the road network expanded, which has led to increasing pressure on the land resources. As the smallholders have to produce increasing amounts of food supplies for the neighboring cities, fallow periods are shortened, and soils and fallow vegetation have become degraded. Although the Bragantina region is an old colonized region, other tropical areas along the Amazonian basin have been recently deforested and 30 % of these areas are covered by secondary forests (Fearnside and Guimarães, 1996; Houghton et al., 2000). Alternatives uses for secondary forest must be developed in order to avoid the degradation of further areas. Forest management and atmospheric carbon sequestration of secondary forest are alternatives to be explored.

Coffea arabica, one of the economically most important crops worldwide, occurs naturally in the undergrowth of montane rainforests of Ethiopia. The study provides the first detailed ecophysiological investigations of wild coffee populations. It demonstrates the inter- and intra-regional variability in phenotypic and hydrological characteristics of wild coffee. The results reveal very different strategies of wild coffee seedlings for coping with drought stress. The ecophysiological diversity shows the importance of Ethiopian wild coffee populations as gene pools for future breeding programs, and underlines the need for an in-situ conservation strategy. The study includes recommendations for coffee forest management and the use of wild arabica coffee in Ethiopia.

Solanum quitoense (Lulo) from the northern Andes is a fruit with an attractive taste. It has a high export potential but its production is hampered by insufficient pollination. Studies on the reproductive system of Lulo revealed that, due to their poricidal anthers, the flowers need pollinators for self- and cross-pollination. Pollination by native bumblebees significantly increases fruit set and quality. Experiments show that colonies of Bombus atratus can be reared in captivity and used in Lulo fields for providing increased pollination services. Modeling based on data on colony development reveal larva/workers ratio and the supply of pollen as main parameters for improving the rearing method.

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.