Do Lagged Ecosystem Feedbacks to Hydroclimate Extremes Promote Resilience of Forest Watersheds?

Abstract Hydroclimate extremes (e.g., droughts and wet periods) can significantly alter forest ecohydrological processes. Severe growing‐season droughts can reduce leaf area index (LAI), tree conductivity, and growing‐season length through early senescence. These strategies reduce transpiration (green water use), conserve subsurface water storage while promoting greater recharge from precipitation. Conversely, high rainfall can boost seasonal soil moisture, stimulating growth and expansion of leaf area, which increases forest water use; however, this may cause extensive cloud cover that limits radiation and photosynthetic rates. These adaptive ecosystem responses often exhibit significant time lags, manifesting months or years after the extreme events. Understanding these lagged feedbacks is essential for assessing forest resilience and projecting future freshwater regimes amid increasing hydroclimate extremes. In this study, we applied the Regional Hydro‐Ecological Simulation System (RHESSys) to the Beetree Creek watershed near Asheville, North Carolina. We found a non‐linear correlation between late‐growing‐season LAI (August and September) and cumulative early‐growing‐season precipitation anomalies (May–July). Specifically, extreme dry or wet early growing seasons reduce late‐growing‐season LAI and cumulative growing‐season gross primary productivity. These correlations are also modulated by topography: riparian zones show a reduced sensitivity to hydroclimate variations compared to upslope areas due to lateral subsurface flow subsidies from upslope. These lagged feedbacks may serve as critical resilience mechanisms for Appalachian forest ecosystems, reducing vegetation water consumption during dry periods to conserve water and promoting recharge when precipitation increases.