A systematic review on the aboveground biomass and carbon stocks of Indian forest ecosystems

Background: Tropical forests play a crucial role as source and sink in global carbon cycle. Development and other anthropogenic activities have led to degradation of forest land, and ultimately, it results in loss of biodiversity and increases concentration of CO2 in atmospheres. Therefore, there is urgent need to estimate regional and national level carbon stock for making forest-based policies and strategies for mitigation of CO2. Patchy and sporadic information is available on biomass and carbon stock of Indian forests. The paper presents a systematic review and comprehensive account of studies conducted in different forest types in India. Result: There are six major forest types found in India consisting of 15 groups and other subgroups with peculiar characteristics. Methodologies used by researchers for biomass/carbon stock estimation are destructive, nondestructive, tree inventories data, species-specific biomass estimation, and remote sensing. Majority of estimates are based on nondestructive allometric equation approach. Studies showed positive correlation between tree species, diameter at breast height, and biomass/carbon stock. Small-and medium-sized growing trees, invasive species, mixed forest, Agroforestry, and Agrosilviculture also play an important role in atmospheric carbon assimilation. The results of diverse forest carbon stock studies are broadly categorized in North, Central, and Southern India. Present review will be helpful for developing conservation policies and decision to increase carbon stock and also REDD+ program for particular forest ecosystem. Conclusion: The systematic literature review was carried out to gather and summarize information from different studies conducted on forest ecosystems and quantification methods used for biomass estimation and carbon stock in different forests types and states of India. In general, great variability occurs in aboveground biomass and carbon stock on account of climatic and geographic differences. To obtain good and accurate estimations, following nondestructive approach, species-specific density-based equations are required from different habitats and also in relation to degradation status of forests. As such regional volume equations would increase error of estimations. The comprehensive account of data would be helpful to formulate strategies based on carbon sequestration in Indian forests for CO2 mitigation.