Carbon Sequestration Potential of Commercial Agroforestry Systems in Indo-Gangetic Plains of India: Poplar and Eucalyptus-Based Agroforestry Systems

Climate change, land degradation, and desertification lead to the loss of carbon present in the soil and plants. The carbon dioxide (CO2) concentration in the atmosphere has reached 412 ppm. This is a rise of 47% since the start of the industrial period, when the concentration was close to 280 ppm. Therefore, the sequestration of carbon from the atmosphere to earth is the need of the hour. Many scientists have suggested agroforestry as a potent instrument for climate change mitigation as well as to fetch lucrative benefits. The Indian government is also promulgating tree-based systems for increasing tree cover up to 33% of the total geographical area to mitigate climate change. Therefore, the expansion of the commercial agroforestry system of fast-growing tree species producing higher biomass could be a sustainable and ecologically benign technique to sequester carbon, increase green cover, and improve the financial status of farmers. This review highlights the commercial agroforestry systems, biomass and carbon sequestration potential, and case studies of poplar and eucalyptus. The species such as poplar (Populus deltoides), nilgiri (Eucalyptus spp.), subabul (Leucaena leucocephala), tree of heaven (Ailanthus excelsa), willow (Salix spp.), malabar neem (Melia dubia), cadamba (Neolamarckia cadamba), and white teak (Gmelina arborea) are the suitable tree species for carbon sequestration under agroforestry. Among these species, poplar and eucalyptus are major agroforestry tree species that have been adopted by millions of farmers in India since the 1990s. Indo-Gangetic plains are considered the birthplace of commercial or industrial agroforestry, as poplar and eucalyptus are widely planted. This review reports that poplar and eucalyptus have the potential to sequester carbon stock of 212.7 Mg C ha−1 and 237.2 Mg C ha−1, respectively. Further, the net carbon sequestration rate in poplar and eucalyptus was 10.3 and 12.7 Mg C ha−1 yr−1, respectively. In conclusion, the commercial agroforestry system was very successful in the Indo-Gangetic regions of the country but needs further expansion with suitable compatible crops in different parts of the country.