Environmental control on carbon exchange of natural and planted forests in Western Himalayan foothills of India

India has committed to increase carbon sequestration by forests under the Nationally Determined Contributions (NDC). However, the CO2 carbon exchange characteristics (Gross Primary Productivity, Net Ecosystem Exchange, and Ecosystem respiration) of Indian forests are poorly understood. Immense carbon sequestration opportunities exist with the natural as well as planted forests. Therefore, it becomes vital to assess the potential of existing forests (natural and planted) by means of the most accurate and reliable methods of eddy covariance (EC). It is also important to know the eco-physiological response of the forests towards diurnal, seasonal, and yearly changes in the prevailing environmental conditions. We analyzed CO2 carbon exchange characteristics of a mature moist deciduous forest and a young mixed deciduous plantation located in the sub-tropical climate regime in the western Himalayan foothills of India with the help of co-located EC measurements (2016 to 2018). The study reveals that both the mature forest (- 719.43 gCm(- 2)year(- 1)) and young plantation (- 467.49 gC m(- 2) year(- 1)) are absorbing a significant amount of atmospheric CO2 carbon. The maximum uptake of atmospheric CO2 occurred during the post-monsoon season in both the forests. The minimum NEE of the mixed deciduous plantation was observed during the leaf fall period while the NEE of the moist deciduous forest was the lowest in monsoon due to a higher respiration rate during monsoon. Among the environmental factors, soil moisture showed maximum control on the productivity of both the forest ecosystems. The value reported in this study can help Forest Survey of India in establishing/assessing emission factor for these particular forest types. This study can also help forest managers in carbon assessment of plantation under NDC.