Biomass stocks and carbon storage in Barringtonia acutangula floodplain forests in North East India

Abstract

Floodplain forests serve a critical function in flood regulation and the global carbon (C) cycle due to their important role in C sink management. Barringtonia acutangula, a tree species adapted to floodplains has been managed traditionally over millennia as family and community forest in North East India. Prevailing traditional management of the Barringtonia forest restricts felling of trees while promoting uses of tree branches in fishery management and fuel wood production. Such management systems might have helped in sustaining floodplain family forests with a steady stock of biomass. However, our knowledge of their role in biomass stocks and C storage is still scanty. Therefore, the present study was undertaken to estimate the biomass and carbon stocks of Barringtonia forests and to understand their role in carbon sink management. The floodplain forest at the study site was stocked with 3204 trees ha−1 of Barringtonia. Allometric models were developed using harvested tree, and these were used for estimation of biomass and vegetation carbon stocks. Among the various models tested the power model using diameter at breast height (DBH) as an independent variable fitted tree biomass in different tree components (bole, sprout, branch and leaves) adequately. Total dry above ground biomass (AGB) estimated at 552 ± 23 Mg ha−1 in the Barringtonia floodplain forests was much larger than AGB reported for various forest types and agroforestry systems in North East India. Biomass allocation patterns revealed that out of the total biomass, the bole contributed the highest proportion (45%) followed by sprouts (27%), branches (24%) and leaves (4%). The above-ground carbon stock was estimated at 263 ± 11 Mg ha−1. The quantity of biomass stock and the carbon storage in vegetation cover of Barringtonia forest suggest its direct influence on local, regional and even global climate.