Ecosystem Level Carbon and Net Primary Productivity of an Old-Growth and a Regenerating Humid Tropical Forest of North-Eastern India

Abstract

Ecosystem level carbon and net primary productivity (NPP) estimates for old-growth and regenerating tropical forests of India are lacking. The study was conducted to estimate ecosystem level carbon contents and NPP, based on above and below ground biomass of trees, shrubs and herbs in an old growth and a regenerating humid tropical forest of Nongkhyllem Wildlife Sanctuary, Meghalaya in north-eastern India. Soil carbon contents were also estimated in both the forest types to estimate ecosystem level carbon. The tree above ground biomass values in old-growth and regenerating forests were 313.8 and 152.4 Mg ha-1 and the below ground values were 50.8 and 30.3 Mg ha-1, respectively. The corresponding total above ground biomass values including trees, litter, herb and shrub components were 323.7 and 159.3 Mg ha-1, respectively. Of the total ecosystem biomass values of 374.5 Mg ha-1 in the old-growth forest, 86% was in the above ground and 14% was in the below ground compartment. The corresponding proportions in the regenerating forest with total biomass of 189.6 Mg ha-1 were 84% and 16%, respectively. The total ecosystem carbon contents in old-growth and regenerating forests were 265.5 and 147.8 Mg C ha-1, of which soil organic carbon was 83.2 and 55.6 Mg C ha-1, respectively that contributed 31.3% and 37.6% to the total ecosystem carbon in the respective forests. However, ecosystem NPP in the regenerating forest (18.4 Mg ha-1 yr-1) was greater than the old growth forest(13.6 Mg ha-1 yr-1)