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Abstract
In 2018, a severe drought caused widespread dieback of two dominant southwestern tree species, Utah juniper (
Juniperus osteosperma, hereafter referred to as juniper) and twoneedle pinyon (
Pinus edulis, hereafter referred to as pinyon). Drought-induced pinyon dieback has occurred several times over the past three decades. However, this dieback of juniper (generally considered one of the most drought-tolerant tree species in the United States) is likely unparalleled in severity and spatial extent. This raises significant concerns regarding the fate of woodland ecosystems in the American Southwest as the climate continues to change. The recent severe drought in 2020–2021 was also associated with widespread juniper mortality, largely clustered in northern Arizona and across southern Utah. However, prior to this project, the extent and spatial patterns of juniper dieback had yet to be resolved, along with its underlying mechanisms and impacts on ecosystem function. This study leveraged a multiscale approach spanning ecophysiology, dendrochronology, pathology/entomology, and remote sensing to ask questions pertaining to three key objectives: (1) quantify the spatial patterns of juniper dieback, (2) diagnose the drivers of juniper dieback, and (3) understand the ecological functioning of pinyon-juniper woodlands during the megadrought.
Parent Publication
Citation
Anderegg, William R.L.; Kannenberg, Steven A. 2025. Linking physiology to landscape-scale dieback of Utah juniper during an ongoing megadrought. In: Conkling, B.L.; Pandit, K., eds. Forest Health Monitoring: Evaluation Monitoring project summaries 2023. Gen. Tech. Rep. WO-105a. Washington, DC: U.S. Department of Agriculture, Forest Service: 75–79. Chapter 9. https://doi.org/10.2737/WO-GTR-105a-Chap9.
