Forests occupy ~30% of Earth’s terrestrial surface, but account for ~50% of terrestrial plant productivity, ~45% of terrestrial carbon storage, and play similarly (disproportionately) important roles in other global biogeochemical cycles, thus providing myriad ecosystem services. Understanding how abiotic and biotic factors influence the physiology of forest organisms, and how physiological mechanisms regulate ecosystem processes and biogeochemical cycles (i.e., forest ecophysiology) is key to maintaining ecosystem services under intensifying natural and anthropogenic pressures. Forest organisms range 22 orders of magnitude in mass from the tiniest microbes to the largest trees and ecophysiological techniques measure processes at spatial scales that span even more orders of magnitude in size from tracing individual molecules to satellite imagery of regional, continental, and global landscapes. In this session, we broadly explore current research designed to improve our understanding of interactions between forest physiological mechanisms and ecosystem processes in both managed and unmanaged forest ecosystems worldwide.