WARMER AND DRIER CLIMATE CONDITIONS HAVE THE POTENTIAL TO INCREASE THE SEVERITY OF BARK BEETLE OUTBREAKS IN LOBLOLLY PINE (PINUS TAEDA) PLANTATIONS AND CAUSE BILLIONS OF DOLLARS IN DAMAGE. LOBLOLLY PINE IS THE MOST IMPORTANT TIMBER SPECIES IN THE SOUTHEASTERN US AND IS PLANTED ON OVER 19 MILLION HECTARES. A MAJOR PEST OF LOBLOLLY PINE ARE BARK BEETLES THAT BORE INTO THE TREE TO LAY THEIR EGGS, CAUSING SEVERE DAMAGE AND TREE DEATH. WHILE SOUTHERN PINE BEETLE (DENDROCTONUS FRONTALIS) IS THE MOST IMPORTANT INSECT PEST, OTHER BARK BEETLES SUCH AS IPS SPECIES CAN CAUSE DAMAGE IN DENSE STANDS OR WHERE DEBRIS FROM LOGGING IS NOT REMOVED AND MAY BE AN EMERGING THREAT TO WATER-STRESSED STANDS BASED ON RECENT OUTBREAKS IN OKLAHOMA AND ARKANSAS. COLD WINTERS ARE A KEY CONSTRAINT ON BARK BEETLE POPULATIONS, BUT RECENT WARMING TRENDS IN CLIMATE COULD MAKE BARK BEETLE OUTBREAKS WORSE IN THE SOUTHEAST. ACROSS WESTERN NORTH AMERICA, WARMER WINTERS IN RECENT DECADES HAVE LED TO A WIDESPREAD AND ONGOING BARK BEETLE OUTBREAK THAT HAS KILLED TREES ON OVER 60 MILLION HECTARES. WHILE EASTERN FORESTS HAVE BEEN SPARED THIS LEVEL OF DESTRUCTION, WORSENING OUTBREAKS OF BARK BEETLES IN LOBLOLLY PINE PLANTATIONS HAVE THE POTENTIAL TO CAUSE BILLIONS OF DOLLARS IN DAMAGE.THE PRIMARY DEFENSE MECHANISM AGAINST BARK BEETLES IN LOBLOLLY AND OTHER PINES IS THEIR PRODUCTION OF A VISCOUS RESIN WHICH PHYSICALLY PUSHES OUT ATTACKING BEETLES AND IS ALSO TOXIC TO THEM. RESIN PRODUCTION AND THE EXTENSIVENESS OF THE RESIN DUCT NETWORK BOTH VARY WITH ENVIRONMENTAL CONDITIONS AND ARE GOOD PREDICTORS OF TREE SURVIVAL FROM BEETLE ATTACKS. LOBLOLLY PINE IS KNOWN FOR ITS RAPID UPREGULATION OF RESIN FLOW IN RESPONSE TO BEETLE ATTACK, SUCH THAT THE EXTENT OF ITS RESIN DUCT SYSTEM CAN SERVE AS A MEASURE OF THE MAXIMUM POTENTIAL DEFENSIVE RESPONSE.BY ALTERING SILVICULTURAL PRESCRIPTIONS, INTENSIVELY MANAGED LOBLOLLY PINE PLANTATIONS AFFORD THE FLEXIBILITY TO TAKE PROACTIVE STEPS TO INCREASE RESILIENCE AGAINST OUTBREAKS. WITH AN UNDERSTANDING OF WHICH SILVICULTURAL PRACTICES ARE EFFECTIVE TO INCREASE DEFENSES AND HOW THESE AFFECT TIMBER PRODUCTION, MANAGEMENT ACTIONS CAN BE TAKEN TO MINIMIZE OR PREVENT FUTURE BARK BEETLE OUTBREAKS AND ECONOMIC LOSSES ACROSS THE SOUTHEASTERN US. OUR OVERALL GOAL IS TO DETERMINE HOW SILVICULTURAL TREATMENTS INTERACT WITH CLIMATE VARIABILITY TO INFLUENCE LOBLOLLY PINE DEFENSES IN ORDER TO DEVISE MANAGEMENT STRATEGIES THAT INCREASE RESISTANCE AGAINST BARK BEETLES WITHOUT SACRIFICING PRODUCTIVITY AND ECONOMIC VALUE. OUR CENTRAL HYPOTHESIS IS THAT PLANTATIONS WHICH MAINTAIN MODERATE GROWTH RATES OF INDIVIDUAL TREES WILL MAXIMIZE RESIN DUCT FORMATION. IN CONTRAST, STRATEGIES THAT INCREASE STRESSES ON INDIVIDUAL TREES OR PUSH THEIR GROWTH TOO QUICKLY WILL REDUCE RESIN DUCT FORMATION. THIS RESEARCH WILL PROVIDE FOREST MANAGERS WITH STRATEGIES TO INCREASE LOBLOLLY RESISTANCE TO BARK BEETLES WHILE MAINTAINING STAND-LEVEL TIMBER PRODUCTION.PINE PLANTATION MANAGEMENT TYPICALLY FOCUSES ON PRODUCING HIGH YIELDS OF THE MOST VALUABLE PRODUCTS AND INVOLVES FLEXIBLE PRESCRIPTIONS THAT VARY TILLAGE (TYPE AND INTENSITY), GENOTYPE SELECTION, PLANTING DENSITY, INTERSPECIFIC COMPETITION CONTROL (HARDWOODS AND/OR HERBACEOUS), THINNING (TIMING AND INTENSITY), AND FERTILIZATION. GIVEN THE LIKELIHOOD OF INCREASING INSECT AND PATHOGEN OUTBREAKS, GREATER EMPHASIS ON INCORPORATING STRATEGIES TO INCREASE RESILIENCE TO ATTACK SHOULD BE CONSIDERED. HOWEVER, IT REMAINS UNCLEAR HOW MANAGEMENT ACTIONS TAKEN TO INCREASE STAND RESISTANCE TO BARK BEETLE OUTBREAK CAN BE BEST BALANCED WITH HIGH PRODUCTION.FOR LOBLOLLY PINE, DECADES OF RESEARCH HAVE FOCUSED ON MANAGEMENT TO REDUCE THE EXPANSION OF SOUTHERN PINE BEETLE INFESTATIONS ONCE THEY OCCUR, BUT MUCH LESS ATTENTION HAS BEEN PAID TO PREVENTING INFESTATION FROM OCCURRING. PRIOR STUDIES ON LOBLOLLY DEFENSE HAVE BEEN LIMITED IN SCOPE BECAUSE OF A FOCUS ON RESIN FLOW, A TIME-CONSUMING MEASUREMENT THAT IS CHALLENGING TO PERFORM ACCURATELY. IN COMPARISON, RESIN DUCT MEASUREMENT REQUIRES ONLY A FRACTION OF THE FIELDWORK, MAKING A REGIONAL-SCALE LOBLOLLY PINE DEFENSE ASSESSMENT FEASIBLE. MOREOVER, A TREE-RING APPROACH TO RESIN DUCTS ENABLES ASSESSMENT IN EACH YEAR OVER THE LIFETIME OF A TREE IN RESPONSE TO VARIATION IN CLIMATE, COMPETITION, AND PLANTATION MANAGEMENT, WHICH CAN BE RELATED TO GROWTH AND VOLUME PRODUCTION OF A FOREST STAND.WE ARE WELL PREPARED TO UNDERTAKE THIS RESEARCH. CO-PD ROD WILL IS AN EXPERT IN LOBLOLLY PINE SILVICULTURE, GROWTH AND PHYSIOLOGICAL RESPONSES. PD HENRY ADAMS HAS EXPERTISE IN TREE-RING SCIENCE AND ON STUDYING THE EFFECT OF CLIMATE VARIABILITY ON TREE STRESS AND MORTALITY. OUR PRELIMINARY DATA FROM A PILOT PROJECT ON LOBLOLLY PINE XYLEM RESIN DUCT RESPONSES TO CLIMATE VARIABILITY AND MANAGEMENT DEMONSTRATE THE FEASIBILITY OF OUR APPROACH.WE BELIEVE OUR PROPOSED RESEARCH IS CREATIVE AND ORIGINAL BECAUSE NO RANGE-WIDE ASSESSMENT OF RESIN DEFENSE AGAINST BARK BEETLES HAS YET BEEN MADE FOR LOBLOLLY PINE, NOR ANY OTHER PINE SPECIES. OUR APPROACH IS ALSO INNOVATIVE BECAUSE MEASUREMENT OF RESIN DUCTS IN GROWTH RINGS ENABLES US TO RETROSPECTIVELY ASSESS TREE DEFENSES OVER THE ENTIRE LIFE OF THE TREE. WE ANTICIPATE THAT THIS RESEARCH WILL GREATLY INCREASE THE REGIONAL-SCALE UNDERSTANDING OF LOBLOLLY PINE VULNERABILITY TO BARK BEETLE OUTBREAKS AND IMPROVE MANAGEMENT AND PLANNING. BY QUANTIFYING TRADEOFFS BETWEEN DEFENSE AND VOLUME PRODUCTION, OUR STUDY WILL MAKE IT POSSIBLE FOR FOREST MANAGERS TO INCREASE LOBLOLLY RESISTANCE WITHOUT SACRIFICING TIMBER PRODUCTION.