Under drought conditions associated with climate change in much of the western USA, tree stress is expected to increase to due maladaptation to drought, thereby potentially amplifying the impact of forest diseases. It is hypothesized that increased risk of forest root diseases will be driven by forest pathogens that are directly and indirectly affected by climatic changes and are associated with woody tissues, such as root and canker diseases, and overall forest declines. Root diseases, such as those caused by Armillariaspp., are especially important in western forests. These root diseases are predicted to become more severe, impacting growth loss and mortality in diverse tree hosts, and potentially expand into new geographic regions where climatic conditions enhance tree stress.
Results/Conclusions
Potential impacts of Armillaria root disease is predicted by determining the suitable climate space for both pathogen and host, and then predicting geographic regions with the respective suitable climate space under current and changing climates. Using maximum entropy bioclimatic modeling, the adaptive range of Armillaria solidipes (a predominant Armillaria pathogen) is predicted to shift to new areas, while also persisting in many areas, of the inland northwestern USA. Increased root disease (tree mortality and growth loss) is expected in areas where the pathogen is climatically adapted but the host is maladapted. However, other factors, such as changes in soil microbial communities also likely influence impacts of Armillaria root disease. This presentation will investigate how drought may generally impact forest disease severity. Further, steps to better understand the potential impacts of Armillaria root disease in western USA forests will be discussed, while highlighting the need to understand complex interactions among biological (soil microbial communities), climatic, and environmental factors that influence this disease under current and changing climatic scenarios.