THE ECONOMIC AND SOCIETAL IMPACTS OF INCREASING DROUGHT STRESS ON U.S. FORESTS ARE NUMEROUS, RANGING FROM DIRECT CONSEQUENCES AFFECTING TIMBER PRODUCTIVITY AND WATER QUALITY, TO INDIRECT IMPACTS SUCH AS INCREASED WILDFIRE AND INSECT ACTIVITY. RECENT "HOT DROUGHTS" HAVE DRIVEN LARGE-SCALE DECLINES IN FOREST PRODUCTIVITY AND TRIGGERED TREE MORTALITY IN MULTIPLE SPECIES IN THE WESTERN U.S. HOWEVER, THE OVERALL IMPACT THAT CHANGING DROUGHT CONDITIONS MAY HAVE ON U.S. FORESTS DEPENDS ON HOW ATMOSPHERIC CO2 FERTILIZATION STIMULATES FOREST GROWTH AND HOW THIS INTERACTS WITH MORE FREQUENT AND SEVERE DROUGHT CONDITIONS. UNDERSTANDING HOW DROUGHT AND CO2 FERTILIZATION IMPACT FOREST PRODUCTIVITY WILL ENABLE BETTER FORECAST EFFORTS. THUS, THIS RESEARCH WILL HELP ILLUMINATE KEY FORESTS MANAGEMENT STRATEGIES FOR MAINTAINING PRODUCTIVITY AND SUSTAINABILITY OF THESE SYSTEMS IN THE FUTURE.IN THIS RESEARCH PROJECT, WE WILL USE MODEL SIMULATIONS, FOREST SURVEYS, AND PREVIOUS STUDIES OF THE IMPACTS OF CO2 FERTILIZATION ON PLANT GROWTH TO A) UNDERSTAND HOW TREES DIE FROM DROUGHT, B) QUANTIFY THE IMPACT OF CO2 FERTILIZATION ON TREE GROWTH, AND C) ESTIMATE THE COMBINED EFFECTS OF CO2 FERTILIZATION AND DROUGHT ON FORESTS PRODUCTIVITY, RESILIENCE, AND SUSTAINABILITY IN FUTURE CONDITIONS.THIS RESEARCH IS IMPORTANT BECAUSE IT DIRECTLY ASSESSES HOW DROUGHT AND CO2 INTERACTIVELY AFFECT TREE PHYSIOLOGY AND WATER LOSS IN FUTURE CLIMATES, WHICH WILL INFORM FUTURE FOREST MANAGEMENT PLANS. THE RESEARCH WILL PROVIDE 1) FOUNDATIONAL RESEARCH AND MODEL DEVELOPMENT THAT ADVANCES OUR SCIENTIFIC ABILITY TO FORECAST HOW CLIMATE CHANGE CAN INFLUENCE AGROECOSYSTEM PROCESSES, AND 2) WILL FACILITATE IMPROVEMENTS TO FOREST MANAGEMENT PLANS ACROSS U.S. FORESTS. BROAD-SCALE SOCIETAL BENEFITS INCLUDE ECONOMIC BENEFITS OF MORE RESILIENT FORESTS AND IMPROVED FORECASTING ABILITIES THAT WILL ENABLE PLANNING FOR CHANGES IN TIMBER PRODUCTION, AMONG OTHERS, TO LOCAL COMMUNITIES.