Ecosystem carbon budgeting under Swietenia macrophylla King plantation in sub humid foothills of Eastern Himalayans of India

Global warming, threats to humankind as driven by the emissions of different greenhouse gases (GHGs) including carbon dioxide (CO2), is becoming a great concern to deal with the vagaries of climate. Plantation ecotypes with greater carbon(C) sink capability are leading among the potential abatement strategies for sequestration of terrestrial C. The present investigation emphasizes on total C stock and litter C status under 13 years old Swietenia macrophylla (Mahogany) pure plantation in Terai belt of West Bengal, India. Stratified tree technique was adopted to estimate the above ground biomass through non-destructive method whereas quadrate method of sampling was followed for estimating leaf litter. The present investigation showed that the total above ground biomass (AGB) of the plantation was 179.73 Mg ha−1 including 95.02 Mg ha−1 (52.83%) shared by stem and in other hand the branch contributed 55.37 Mg ha−1 (30.81%) and the remaining 29.34 Mg ha−1 (16.32%) by leaves. The below ground (root) biomass (BGB) was assessed to be 53.91 Mg ha−1. The biosphere part recorded C was 109.81 Mg ha−1, comprising the total C of AGB and BGB of 84.47 Mg ha−1 and 25.34 Mg ha−1, respectively. Soil C stock (at 0–60 cm) of 40.36 Mg ha−1 comprised 25.30 Mg ha−1 at 0–20 cm followed by 10.46 Mg ha−1 at 20–40 cm and 4.60 Mg ha−1 at 40–60 cm depth, respectively. The total litter production was 6.92 Mg ha−1 yr−1 in 2016–17 and 8.39 Mg ha−1 yr−1 in 2017–18, respectively. The amount of total C storage of plantation was observed to be 150.17 Mg ha−1, comprising 109.81 Mg ha−1 in biosphere and 40.36 Mg ha−1 in soil. The litter C stock of 3.48 Mg ha−1, was excluded from the ecosystem carbon budgeting (ECB), because it acts as a transitional between lithosphere and biosphere. Conclusively, the mahogany-based plantation is not only remunerative to the farmers but also provisions significant improvement in soil fertility along with C sequestration which deploys a crucial part in the sustainable maintenance of the ecosystem in addition to providing a guideline for ECB of the plantation.