Influence to the society due to climate change and human interaction to the natural resources often takes place through changes of hydrologic and biogeochemical cycles in terrestrial ecosystems. As such it is essential to understand the role of ecosystem in the environment homeostasis. This can be accomplished by mutli-scale observations of hydrologic and biogeochemical cycles in terrestrial ecosystems. This session aims at promotion of such studies by reviewing knowledge we have accumulated so far and by discussing directions, methodology and organization of such investigations in the coming decades.