THE TIMING OF PHENOLOGICAL EVENTS (SPRING LEAF EMERGENCE) EXERTS STRONG CONTROL OVER EXCHANGES OF CARBON, WATER, AND ENERGY BETWEEN THE LAND SURFACE AND THE ATMOSPHERE AT THE STAND SCALE. SPRING LEAF EMERGENCE INITIATES THE DECIDUOUS FOREST'S GROWING SEASON AND REPRESENTS A SIGNIFICANT DRIVER OF ECOSYSTEM PRODUCTIVITY, SOIL RESOURCE ACQUISITION, AND CARBON DYNAMICS. OBSERVATIONS OF STAND-SCALE PHENOLOGY, FROM REMOTE SENSING AND REPEAT DIGITAL IMAGERY NETWORKS HAVE SUBSTANTIALLY ADVANCED OUR UNDERSTANDING OF THE VARIABILITY IN PHENOLOGICAL TIMING. HOWEVER, WHILE THE IMPORTANCE OF STAND-LEVEL PHENOLOGY ON ECOSYSTEM PROCESSES IS CLEAR, WE HAVE A VERY LIMITED UNDERSTANDING OF INTRA- AND INTER-SPECIFIC VARIABILITY IN SPECIES-LEVEL PHENOLOGY.UNDERSTANDING HOW TREE SPECIES RESPOND TO THESE CHANGES IS CRITICAL FOR UNDERSTANDING FUTURE FOREST ECOSYSTEM SERVICES INCLUDING PROTECTION OF SOIL AND WATER RESOURCES AND MITIGATION OF CLIMATE CHANGE. MOST STUDIES TO DATE HAVE BEEN FOCUSED ON RESPONSES AT THE FOREST SCALE, WITH MUCH LESS ATTENTION GIVEN TO THE SPECIES-SPECIFIC RESPONSES, WHICH IS A SIGNIFICANT GAP BECAUSE SPECIES RESPOND DIFFERENTLY TO ENVIRONMENTAL CHANGE. SPECIES THAT LEAF OUT EARLIER MAY HAVE A COMPETITIVE ADVANTAGE IN TERMS OF CARBON UPTAKE LEADING TO INCREASES IN GROWTH IN SOME SPECIES AND DECREASED GROWTH FOR OTHERS. THIS HAS IMPLICATIONS FOR THE VALUE OF THE TIMBER BEING HARVESTED IN A FOREST STAND, DEPENDING ON WHETHER THE HIGHER OR LOWER VALUE TIMBER SPECIES ARE EXPERIENCING INCREASED GROWTH. HOWEVER, ANY ADVANTAGE IN CARBON GAIN MAY COME WITH DISADVANTAGES TO THE WATER BUDGET. IF HIGH WATER USERS ARE LEAFING OUT EARLIER WITH WARMER SPRINGS, THIS COULD REDUCE SUMMER WATER SUPPLY IN YEARS WITH LESS PRECIPITATION WHICH WILL POTENTIALLY LEAD TO WATER SHORTAGES FOR HUMAN POPULATIONS LIVING DOWNSTREAM, DEPENDING ON SURFACE WATER SUPPLY.BY LEVERAGING EXISTING NETWORKS INCLUDING DIGITAL IMAGERY OF FOREST CANOPIES, TREE-RING CHRONOLOGIES, AND CARBON AND WATER CYCLING, I WILL QUANTIFY SPECIES-SPECIFIC LEAF PHENOLOGICAL VARIABILITY AND DETERMINE THE ROLE THIS VARIBILITY HAS IN TREE GROWTH, CARBON, AND WATER CYLING DYANMICS. INDIVIDUAL TREE SPECIES WILL BE IDENTIFIED WITHIN THE DIGITAL IMAGE OF THE CANOPY BY USE OF A UAV AFFIXED WITH A DIGITAL CAMERA THAT WILL BE FLOWN ABOVE THE FOREST CANOPY. VISUAL INSPECTION AND INTEGRATION OF FOREST TREE SPECIES IDENTIFICATION INTO THE EXISTING DIGITAL IMAGE OF THE CANOPY WILL ALLOW FOR THE DEVELOPMENT OF A SPECIES-SPECIFIC TIME SERIES OF LEAF PHENOLOGICAL TRANSITIONS. ONCE THESE TRANSITIONS ARE EXTRACTED, I WILL ASSESS THE EFFECT OF THE INTERANNUAL VARIABILITY IN SPRING LEAF EMERGENCE DATE ON VARIABILITY IN BASAL AREA INCREMENT, GROSS PRIMARY PRODUCTIVITY, AND EVAPOTRANSPIRATION.BY EVALUATING COMPLETING THESE METHODS, I WILL DEVLOP A FRAMEWORK TO SYSTEMATICALLY ASSESS SPECIES-LEVEL PHENOLOGICAL TRANSITIONS FOR USE BY ANYONE WITH ACCESS TO THE PHENOCAM NETWORK. I WILL PROVIDE INFORMATION TO FOREST MANAGERS REGARDING HOW SHIFTING PHENOLOGICAL PATTERNS ARE AFFECING TREE GROWTH ACROSS SPECIES TO BETTER INFORM FOREST POLICY AND LAND MANAGEMENT PRACTICES UNDER A FUTURE CHARACTERIZED BY A WARMING CLIMATE.