Global climatic changes affect fluvial processes, such as erosion, on forested slopes and riverbanks. Both the continuous and discontinuous erosion of riverbanks often lead to destabilized and uprooted tree stems. Dating of the stem-wood grown along riverbanks in combination with dendrogeomorphic analysis help to reconstruct the erosion dynamics. The current study analyses the anatomical wood features of exposed roots from European ash (Fraxinus excelsior L.). First results show different reactions in vessel and fiber cell growth: fiber cells show a distinct decrease in lumen width due to the exposure, whereas vessel lumens show a higher variation in width. The results demonstrate that with European ash it is possible to determine the time of exposure at an annual resolution.