The tree-ring anatomy of Robinia pseudoacacia L. As a data source for dendrogeomorphic reconstruction of past landslide movements in the landslide hot-spot of central Europe

Abstract

The chronology of past landslide movements is a key source of information for effective landslide hazard determination. Dendrogeomorphological methods are currently an effective tool for obtaining chronological data but still encounter limitations in extracting landslide signals from yearly series. These limitations can be reduced by introducing anatomical analyses of the yearly series. Black locust (Robinia pseudoacacia L.), a widespread tree species occupying landslides on river banks, has been surprisingly rare in dendrogeomorphology. Thus, this study focused on the effectiveness of using both standard macroscopic signals (tree-ring eccentricity) and anatomical growth responses of this species in a dendrogeomorphic analysis of landslide movements at one of the landslide hot spots in Central Europe (the Váh River bank). Analysis of the eccentricity of tree rings from 67 individuals of R. pseudoacacia allowed us to reconstruct 13 landslide events over the last 49 years. From an anatomical point of view, a strong association was found between a significant reduction in vessel lumen area and the eccentricity of the tree rings and the tilting of the tree stems. A possible cause of the anatomical response is a combination of root damage from subsurface landslide movements and occasional tension wood formation following tree tilting. The constructed chronology confirmed the known years of landslide activity and generally complemented the known chronology. One of the results of the study is the implication for effective evaluation of the spatial extent of landslide activity, considering tree-ring-based magnitude-frequency relationships. The results of this study will thus allow further extension of the use of dendrogeomorphological methods both methodologically and biogeographically.