Not an event but a process: challenging common misconceptions in subalpine forest decline

Extreme weather events (EWEs) are widely recognized as key drivers of ecological change because of their immediate and significant impacts. However, to date, most studies have focused on a most recent event, neglecting the history of EWEs which could reveal accumulated long-term climatic stress. In contrast to EWEs, Climate extremes (CEs) offer prolonged perspective that could address the limitations of a single EWE-based explanation for the abrupt decline of subalpine forest. Here, using the recent subalpine forest decline and climatic dataset in Korea, we identified multiple EWEs occurring prior to dieback. Past EWEs had higher intensity and longer duration than the most recent EWE, suggesting that an EWE itself had limitations in explaining the whole decline process. We therefore propose a novel conceptual framework, which addresses abrupt forest decline with accumulated climatic exposures from CE and response detection threshold. Our conceptual framework explains how abrupt-delayed response is detected through various methods such as remote sensing and dendrometer. In conclusion, CE represents one of the primary drivers of subalpine forest decline and offers an alternative explanation for abrupt dieback events that the latest EWE alone struggles to account for. Further research quantifying detection thresholds of indicators with frequency, intensity and duration of EWE will improve forecasting and management of subalpine forests under increasing climate variability. • CE is often conflated with EWE, but they are distinct. • CE represents persistent climatic exposure that accumulates over time. • Potential cause of Korean fir dieback is cumulative climatic stress. • Climatic extreme stress can erode forest fitness latently, then trigger sudden dieback.