Kichas, Nickolas E.Pederson, Gregory T.Hood, Sharon M.Everett, Richard G.McWethy, David B.2023-12-112023-12-112023-03Kichas NE, Pederson GT, Hood SM, Everett RG and McWethy DB (2023) Increased whitebark pine (Pinus albicaulis) growth and defense under a warmer and regionally drier climate. Front. For. Glob. Change 6:1089138. doi: 10.3389/ffgc.2023.10891382624-893Xhttps://scholarworks.montana.edu/handle/1/18250Introduction: Tree defense characteristics play a crucial role in modulating conifer bark beetle interactions, and there is a growing body of literature investigating factors mediating tree growth and resin-based defenses in conifers. A subset of studies have looked at relationships between tree growth, resin duct morphology and climate; however, these studies are almost exclusively from lower elevation, moisture-limited systems. The relationship between resin ducts and climate in higher-elevation, energy-limited ecosystems is currently poorly understood. Methods: In this study, we: (1) evaluated the relationship between biological trends in tree growth, resin duct anatomy, and climatic variability and (2) determined if tree growth and resin duct morphology of whitebark pine, a high-elevation conifer of management concern, is constrained by climate and/or regional drought conditions. Results: We found that high-elevation whitebark pine trees growing in an energy-limited system experienced increased growth and defense under warmer and regionally drier conditions, with climate variables explaining a substantive proportion of variation (∼20–31%) in tree diameter growth and resin duct anatomy. Discussion: Our results suggest that whitebark pine growth and defense was historically limited by short growing seasons in high elevation environments; however, this relationship may change in the future with prolonged warming conditions.en-UScc-byhttps://creativecommons.org/licenses/by/4.0/whitebark pine (Pinus albicaulis)growthdefenseresin duct defensessubalpineArticle