** AWARDS ISSUED PRIOR TO JANUARY 20, 2025, WERE FUNDED UNDER PREVIOUS ADMINISTRATIONS AND MAY NOT REFLECT THE PRIORITIES AND POLICIES OF THE CURRENT ADMINISTRATION.** INVASIVE PATHOGENS ARE AN INCREASING THREAT TO FORESTS WORLDWIDE, CAUSING TREE MORTALITY AND REDUCING ECOSYSTEM HEALTH. TO BETTER PREDICT THE IMPACT OF PATHOGENS ON FORESTS, IT IS CRITICAL TO UNDERSTAND HOW TREES RESPOND TO STRESS CAUSED BY INFECTION. JUST LIKE ANIMALS' STORE FAT, TREES STORE CARBOHYDRATES FOR LATER USE, WHICH CAN BECOME ESPECIALLY CRITICAL TO UNDER PERIODS OF STRESS. WHILE CARBOHYDRATE STORES ARE USED BY TREES TO SUPPORT THEIR CONTINUED GROWTH, THEY CAN ALSO BE USED TO BUILD CHEMICAL COMPOUNDS THAT PROVIDE DEFENSE AGAINST PATHOGENS. CARBOHYDRATE DYNAMICS IN LONG-LIVED TREES ARE COMPLEX, HOWEVER, AND THE RELATIONSHIP BETWEEN A TREE'S STORAGE OF CARBOHYDRATES AND THE RELATIVE RATE AND MAGNITUDE OF INVESTMENT IN PHYSICAL AND CHEMICAL DEFENSIVE COMPOUNDS DURING PATHOGEN ATTACK REMAINS LARGELY UNEXPLORED. UNDERSTANDING THESE DYNAMICS MAY BE KEY TO UNDERSTANDING AND WHY SOME TREES LIVE WHILE OTHERS SUCCUMB TO INFECTION. THIS PROJECT INTEGRATES TWO ASPECTS OF A TREE'S PHYSIOLOGY THAT HAVE HISTORICALLY BEEN EXPLORED IN PARALLEL--CARBOHYDRATES AND CHEMICAL DEFENSES--TO IDENTIFY RESOURCE ALLOCATION STRATEGIES AND TRAITS THAT UNDERLY RESISTANCE AGAINST STRESS CAUSED BY NOVEL PATHOGENS WITH AN EYE TOWARDS IMPROVING CONSERVATION AND MANAGEMENT OF HAWAI'I'S THREATENED 'OHI'A TREES.RESULTS FROM THIS WORK WILL PROVIDE URGENT INSIGHT INTO THE ABILITY OF HAWAI'I'S 'OHI'A TREES TO RESIST A NOVEL FUNGAL PATHOGEN (KNOWN AS RAPID 'OHI'A DEATH OR ROD) THAT IS CURRENTLY CAUSING WIDESPREAD MORTALITY WITH SIGNIFICANT AND DETRIMENTAL ECOLOGICAL EFFECTS. 'OHI'A IS THE MOST ABUNDANT NATIVE FOREST TREE THROUGHOUT HAWAI'I AND IS AN INTEGRAL PART OF THE ISLAND'S ECOLOGY, ECONOMY, AND CULTURE. HOWEVER, WITHOUT A BETTER UNDERSTANDING OF 'OHI'A TREE BIOLOGY AND ITS RESPONSE TO STRESS, THE IMPACTS OF ROD AND OTHER INVASIVE PATHOGENS WILL REMAIN UNRESOLVED AND DISEASE MITIGATION MEASURES WILL BE HINDERED. TO MEET THIS CHALLENGE, THE PROPOSED WORK COMBINES FIELD AND GREENHOUSE-BASED EXPERIMENTS TO COMPREHENSIVELY QUANTIFY THE RELATIONSHIP BETWEEN TREE CARBOHYDRATE RESERVES AND THE PHYSICAL AND CHEMICAL DEFENSE RESPONSE TO INFECTION. THE SYNERGISTIC APPROACHES AIM TO ASSESS THE DEGREE TO WHICH DIFFERENT TREE STRATEGIES FOR STORING AND MOBILIZING CARBOHYDRATES IMPROVES RESISTANCE OF 'OHI'A TREES TO ROD. SPECIFICALLY, AIM 1 SEEKS TO IDENTIFY THE NATURAL SEASONAL MINIMA AND MAXIMA OF BOTH NSC RESERVES AND THE DEFENSE METABOLOME IN DIFFERENT TREE ORGANS. THIS INFORMATION IS CRUCIAL TO GUIDE THE TIMING OF AN ARTIFICIAL MANIPULATION OF STEM CARBOHYDRATE RESERVES IN MATURE 'OHI'A TREES IN AIM 2, WHICH WILL DIRECTLY TEST THE ROLE OF RESERVE STATUS IN DETERMINING THE INDUCED TREE DEFENSE RESPONSE AND ITS ROLE IN RESISTANCE AGAINST ROD. AIM 3 THEN EMPLOYS A GREENHOUSE EXPERIMENT TO QUANTIFY GENOTYPE &TIMES; ENVIRONMENT EFFECTS ON RESPONSES TO ROD ACROSS SUSCEPTIBLE AND RESISTANT 'OH,I'A POPULATIONS TO IMPROVE PLANTING STRATEGIES AND INFORM GENETIC TRIALS. TOGETHER, THE MECHANISMS AND RESULTS THAT EMERGE FROM THIS CROSS-DISCIPLINARY RESEARCH AGENDA WILL INFORM THE IMPLEMENTATION OF STRATEGIES TO MITIGATE ROD AND IMPROVE CONSERVATION AND MANAGEMENT OF TROPICAL FORESTS.DRAWING ON A SHARED INTEREST IN IMPROVING RESEARCH WITH NATIVE KNOWLEDGE AND INCREASING THE RECRUITMENT AND RETENTION OF UNDERREPRESENTED GROUPS IN THE SCIENCES, THE TEAM WILL SUPPORT AN AUTHENTIC INDEPENDENT UNDERGRADUATE RESEARCH EXPERIENCE FOR NATIVE HAWAIIAN AND PACIFIC ISLANDER STUDENTS. RESEARCHERS WILL ALSO MEANINGFULLY ENGAGE WITH NATIVE MEMBERS OF THE TROPHTIRC COLLABORATIVE TO FURTHER ITS MISSION TO ADVANCE MANAGEMENT AND TO PROTECT TROPICAL HARDWOOD FORESTS WHILE ALSO GIVING BACK TO THE COMMUNITY, ADDRESSING SHARED ECOLOGICAL CONCERNS, AND PROVIDING TRAINING AND EDUCATIONAL OPPORTUNITIES FOR STUDENTS, POSTDOCS, AND THE BROADER HAWAI'IAN COMMUNITY. THE TEAM WILL THEN INTEGRATE REAL DATA AND KNOWLEDGE GAINED FROM THE WORK INTO UNDERGRADUATE COURSE MODULES, PROVIDING UNIQUE, DATA-BASED CLASSROOM INSTRUCTION THAT WILL PROMOTE CRITICAL THINKING SKILLS REQUIRED TO ADDRESS REAL-WORLD CHALLENGES FACING FOREST ECOSYSTEMS.