Project Grant 20236701242763

**AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** A SUBSTANTIAL AMOUNT OF CARBON DIOXIDE EMISSIONS ARE OFFSET BY WESTERN US FORESTS, WHICH ARE EXPERIENCING INCREASING FIREFREQUENCY, SEVERITY, AND SYNCHRONY. WILDFIRE SMOKE GENERATES GROUND-LEVEL OZONE AND FINE AEROSOLS WHICH HAVE OPPOSING ANDMECHANISTICALLY UNIQUE IMPACTS ON TREE PHOTOSYNTHESIS AND GROWTH. WHILE OZONE MAY REDUCE PHOTOSYNTHESIS AND GROWTH, FINEAEROSOLS MAY HAVE THE OPPOSITVE EFFECT THROUGH INCREASED DIFFUSE RADIATION. HOWEVER, THE INTEGRATED RESPONSE OF FOREST FUNCTIONIS CURRENTLY OVERLOOKED. OUR LACK OF UNDERSTANDING HOW GROUND-LEVEL WILDFIRE SMOKE IMPACTS FORESTS DOWNWIND FROM ACTIVE FIRESLIKELY RESULTS IN AN OVERESTIMATION IN FUTURE PROJECTIONS OF CARBON SEQUESTRATION INTO LONG-TERM STORAGE POOLS. BY NOT CONSIDERINGHOW FORESTS RESPOND TO PERVASIVE WILDFIRE SMOKE, WE SEVERELY LIMIT OUR ABILITY TO ACCURATELY REPRESENT THE FUTURE OF THE COUPLEDCLIMATE-EARTH SYSTEM AND MAY UNDERESTIMATE THE NEGATIVE IMPACTS OF CLIMATE CHANGE IN THE WESTERN US, PARTICULARLY IN AREASTHAT ARE ACTIVELY MANAGED FOR TIMBER PRODUCTION.THIS PROJECT WILL COUPLE INDIVIDUAL TREE-BASED MEASUREMENTS OF GROWTH AND RECONSTRUCTED LEAF GAS-EXCHANGE (I.E.PHOTOSYNTHESIS) WITH ECOSYSTEM LEVEL METRICS OF TREE FUNCTION DETERMINED AT FIVE STUDY LOCATIONS IN THE WESTERN US THAT CONTAINEDDY-FLUX TOWERS OPERATED BY THE NATIONAL ECOLOGICAL OBSERVATORY NETWORK TO RESOLVE THE UNKNOWN IMPACT OF PERVASIVE WILDFIRESMOKE ON FOREST CARBON CYCLING DYNAMICS IN AN ERA OF INCREASING WILDFIRE DEVASTATION. THROUGH THIS PROJECT, WE WILL DEVELOP ANINCREASED UNDERSTANDING OF THE IMPACTS OF WILDFIRE SMOKE ON DOWNWIND FORESTS, THAT WILL BE USED TO DEVELOP AN OPEN-SOURCE,PROCESS-BASED MODEL THAT POLICYMAKERS, FOREST LAND MANAGERS, AND OTHER STAKEHOLDERS WILL BE ABLE TO UTILIZE FOR DECISION MAKINGAND CARBON TRAJECTORY FORECASTING. FINALLY, THIS PROJECT WILL LEAD TO AN IMPROVED ABILITY TO SIMULATE CARBON FUTURE FOREST CARBONCYCLING DYNAMICS, REDUCING OUR UNCERTAINTY AROUND FUTURE CLIMATE PROJECTIONS.