Assessing carbon sequestration in urban Miyawaki forests of south India: Implications for climate mitigation planning and land suitability

Globally, plantation forests are widely recognized as an effective solution to combat land degradation. One such approach of creating plantation forest is the Miyawaki method of afforestation and reforestation, which involves dense planting of native species. This study investigates the carbon sequestration potential of three Miyawaki forests aged 2, 4, and 5 years in the south Indian cities of Bengaluru and Palakkad. We conducted field sampling to measure tree attributes, including Diameter at Breast Height (DBH) and height, which were used to calculate the above-ground biomass (AGB) using species-specific allometric equations. Carbon storage and sequestration rates were then determined based on allometric equations and the age of the Miyawaki forest stands. Our findings reveal that the annual growth rate of forest biomass increases significantly with age, resulting in a total biomass accumulation of 165.7 Mg C/ha within five years of planting. Additionally, carbon sequestration rates showed a rapid increase with forest age, with the 2-year-old forest sequestering 5.284 Mg C/ha-yr, the 4-year-old forest sequestering 20.042 Mg C/ ha-yr, and the 5-year-old forest sequestering 33.084 Mg C/ha-yr. We also identified over 200,000 km² of underutilized marginal land with climatic conditions similar to those of the study sites, offering vast potential for expanding Miyawaki forest interventions. In this context, the Miyawaki method could be positioned within policy interventions aimed at climate mitigation in India and beyond, considering the relevant biophysical and ecological factors.