Abstract:
In recent years, frequent glacial debris flows in the Sanggu watershed along the Zamo Highway have posed a serious threat to the safety of external border corridors. Understanding the historical occurance of debris flows in this watershed is crucial for improving prediction and early warning of debris flow under future climate change conditions. This paper analyzes tree-ring scars and growth release/suppression responses caused by debris flow disturbances based on tree ring growth. Based on revised thresholds for tree-ring growth release and suppression,
Wit values were calculated to reconstruct the timing and inundation extent of debris flows in the Sanggu watershed from 1925 to 2021. The reconstructed events were validated using debris flow timing and extent extracted from remote sensing imagery interpreted via the pixel binary model. The results show that: (1) In the process of reconstructing glacial debris flow in the Sanggu watershed, the weak and strong thresholds for tree-ring growth release/suppression were revised to 25% and 50%, respectively. This revision significantly improves the accuracy of debris flow event identification. (2)In area dominated by old-growth trees, excluding growth releases as a factor when calculating
Wit values reduces the dating accuracy of glacier-type debris flows. (3) In regions lacking historical debris flow data records, combining remote sensing image interpretation with dendrogeomorphology effectively enhance dating accurancy. The integration of remote sensing data and tree-ring records enables a more comprehensive reconstruction of debris flow history and extent.