Carbon Sequestration Potential of Agroforestry Practices in Temperate North America

Abstract

Agroforestry, an ecologically and environmentally sustainable land use, offers great promise to sequester carbon (C). The objectives of this chapter are to (1) provide a review of C sequestration opportunities available under various agroforestry practices in temperate North America, and (2) estimate C sequestration potential by agroforestry in the US. Since accurate land area under agroforestry was not available, the potential C sequestration was estimated based on several assumptions about the area under different agroforestry practices in the US: 1.69 million ha under riparian buffer, 17.9 million ha (10% of total cropland) under alley cropping, and 78 million ha under silvopasture (23.7 million ha or 10% of pasture land and 54 million ha of grazed forests). Based on these, we estimated C sequestration potential for riparian buffers, alley cropping, and silvopasture in the US as 4.7, 60.9, and 474 Tg C year–1, respectively. Establishment of windbreaks to protect cropland and farmstead could sequester another 8.79 Tg C year–1. Thus, the potential for C sequestration under agroforestry systems in the US is estimated as 548.4 Tg year–1. The C sequestered by agroforestry could help offset current US emission rate of 1,600 Tg C year–1 from burning fossil fuel (coal, oil, and gas) by 34%. These preliminary estimates indicate the important role of agroforestry as a promising CO2 mitigation strategy in the US, and possibly in other parts of North America. The analysis also reveals the need for long-term C sequestration research in all regions and for all agroforestry practices, establishment of standardized protocols for C quantification and monitoring, inventory of agroforestry practices, development of models to understand long-term C sequestration, and development of agroforestry design criteria for optimum C sequestration for all regions.