Management of a Top 10 National Wilderness Forest: Insights from the North American Red Squirrel’s ‘squirelscape’ based on Nest and Midden Ecology using GIS, ‘Foto monitoring’, and Machine Learning in the Tanana Valley State Forest, interior Alaska

Context North American red squirrels ( Tamiasciurus hudsonicus ) depend on coniferous forests that provide resources for food, shelter, nests, and middens (food storage sites). In Alaska, old-growth forests with large timber stands support red squirrel populations, yet many of these landscapes remain poorly studied and largely unmanaged. Objectives We investigated red squirrel midden and nest ecology and their associations with habitat and tree stand characteristics in the Tanana Valley State Forest (TVSF) in Interior Alaska. We also assessed temporal changes in midden structure and developed spatially predictive models to evaluate habitat preferences across the landscape. Methods We surveyed 261 middens in 2019 and 53 in 2024, including 28 middens revisited after five years. Midden attributes, habitat structure, and nearby nests were documented, and standardized ‘Foto monitoring’ was used to track midden changes over time. Spatially predictive machine-learning models were developed and validated using independent Forest Inventory and Analysis (FIA) and forest health datasets. Results ‘Foto monitoring’ indicated average midden growth of about 5% over five years, corresponding to roughly 1% annual growth and suggesting midden ages near 100 years. Spatial models showed that prime red squirrel habitats were strongly associated with spruce-dominated stands. Within these stands, squirrels behaved as habitat generalists with weaker associations to old-growth or commercially valuable timber stands, indicating that spruce presence is the dominant predictor of habitat suitability. Conclusions Incorporating these spruce-dominated forest habitat requirements into forest planning could help conserve the Alaskan ‘squirrelscape’ and associated boreal forest ecosystems.