CARBON STOCK, SOIL CO2 FLUX AND CARBON BUDGETS OF DIFFERENT FOREST ECOSYSTEMS OF MANIPUR, NORTHEAST, INDIA

Abstract

Carbon stock and soil CO 2 flux in the vegetation-soil components were assessed in tropical, sub-tropical and temperate forest ecosystems of Manipur, Northeast India. Carbon stock in the aboveground biomass was recorded to be highest in the sub-tropical forest (319.18 Mg ha -1 ) followed by temperate (54.45 Mg ha -1 ) and tropical forest (38.35 Mg ha -1 ) whereas soil organic carbon stock was highest in temperate forest (65.13 Mg ha -1 ) and lowest in tropical forest (21.64 Mg ha -1 ) up to the depth of 1m. The rates of carbon sequestration was in the order of the tropical>temperate> sub- tropical forest and the rate of soil CO 2 flux was estimated to be highest in tropical and lowest in temperate forest. Regression analysis shows that annual soil CO 2 flux was highly influenced by soil moisture, soil temperature and soil organic carbon as well as by C stocks in aboveground biomass. The annual carbon budget of the tropical, sub-tropical and temperate forest shows that 11.41 Mg C ha -1 ,9.84 Mg C ha -1 and 10.34 Mg C ha -1 was captured by the vegetation through photosynthesis, while 10.36 Mg C ha -1 ,5.84 Mg C ha -1 and 8.07 Mg C ha -1 was released into the atmosphere through CO 2 emissions from soil due to root and microbial respiration thereby a net balance of 1.05 Mg C ha -1 yr -1 ,1.77 Mg C ha -1 yr -1 and 2.27 not ( 4.50) Mg C ha -1 yr -1 was being retained in the forest ecosystems. Thus our study indicates that these forests have a huge potential in the reduction of carbon dioxide levels in the atmosphere and could be used as C-sinks in the Northeast India depending upon the level of protection.