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Abstract
Armillaria root disease is one of the leading causes of growth loss and mortality in coniferous forests of the western USA (Lockman and Kearns 2016; Kim et al. 2022). In 2019, a collaborative project was started to learn more about Armillaria root disease in the Intermountain Region (USDA Forest Service Region 4). Recent surveys suggested that Armillaria root disease was increasing on trees in Utah, particularly at higher elevations than was previously observed (John Guyon, per. comm.). Previous and subsequent surveys using DNA-based identification revealed that A. solidipes (formerly known as North American A. ostoyae) was the predominant cause of Armillaria root disease in Utah (McDonald 1999, Hanna unpublished data). Earlier modeling efforts produced preliminary predictions of the geographic distribution of suitable climate for A. solidipes in the Intermountain Region of the USA (Hanna et al. 2021, Kim et al. 2021). These earlier models were limited due to COVID-19-related delays in field surveys and lack of availability of higher resolution bioclimatic grids. Currently, the higher resolution CMIP6 (Coupled Model Intercomparison Project Phase 6) bioclimatic grids are available at 30-second (ca. 1-km) resolution and additional locations of DNA-confirmed A. solidipes have been determined. Refined models are presented based on the newly available information. Information from this project will provide insights for improving other existing bioclimatic models and/or developing new models for Armillaria, other forest pathogens, and/or forest hosts in other regions of western North America. These tools can inform forest managers about how climate change might influence the spatial distribution of suitable climate for this Armillaria root disease pathogen and its hosts, which is an important consideration for forest management in the Intermountain Region.
Citation
Hanna, John W.; Bennett, Patrick I.; Newcomb, Maria; Kim, Mee-Sook; Klopfenstein, Ned B. 2024. Updated bioclimatic modeling of Armillaria solidipes in the Intermountain Region (USA). In: Brooks, Rachel K., compiler. Proceedings of the 68th Western International Forest Disease Work Conference; 5-9 June 2023; Rohnert Park, CA. Online: https://www.wifdwc.org. p. 175-181.
