Earth’s changing climate is affecting the productivity and mortality of tree species worldwide with implications for carbon and water fluxes, nutrient cycling, biodiversity, and economic output. In recent years, considerable research has focused on how warming and drought impacts either tree physiology or biotic agents, but rarely both. A better understanding of the interactions between tree stress and both mutualistic and antagonistic biotic agents is required to improve our understanding of tree mortality. It is well known that increased temperatures and precipitation variability are key drivers of insect and pathogen outbreaks throughout global ecosystems. Yet the complex climate-driven effects, that initiate and sustain outbreaks that often cause large-scale tree mortality events, remain to be elucidated. An enhanced understanding of biotic-abiotic feedbacks is also critical for predicting how forests will respond to both long- and short-term climatic disturbances. To meet this pressing ecological need, the research presented in this symposium will address recent advances towards improving our understanding of these complex relationships. Presenters will offer insights into the latest field and laboratory techniques, and to address the ESA 2020 meeting’s theme, discuss how large complex data sets are being used to model interactions at the local and global scales. The goal of this session is to bring together early-career and senior scientists working in diverse systems to offer a well-rounded and contemporary perspective on the ways in which species interactions are responding to global change, and create new and innovative collaborations. Participants will highlight the need for collaborative and cross-disciplinary research to investigate the interactive effects of environmental and biotic stress including above- and belowground linkages and processes, how they impact future species distributions, and the underlying forces driving tree mortality.