Understanding the dynamics of terrestrial ecosystems in a changing environment is critical because of their fundamental role in the global carbon (C) cycle. Climate extremes, ecological disturbances, and anthropogenic activities are currently altering the functioning of terrestrial ecosystems. As a result, there is a need to improve the monitoring of the terrestrial ecosystem’s functioning and the role of extreme events (i.e. natural and human-induced disturbances) in the biogeochemical cycles for better quantifying regional and global C dynamics. In my thesis, I integrated multiple modeling methods, remote sensing data, climate data, and a global network of eddy-covariance (EC) flux towers to provide insights in understanding the role of forest age and ecological memory effects in controlling carbon dioxide (CO2) fluxes from ecosystem to regional scales. Overall, my thesis demonstrates the importance of ecosystem history for biosphere-atmosphere CO2 exchange.