Aspects of different growth responses of coniferous and broadleaved tree species in landslide research

This study investigates the differing responses of two tree species, P. abies and F. sylvatica, to landslide movements and their subsequent effects on landslide chronologies. These are the two most commonly used tree species in dendrogeomorphic landslide research in Central Europe and their combination is generally recommended. However, their specific effect on the resulting chronology is not yet taken into account although they are two quite different species. The research was conducted on 220 individuals of both species located in the Girová landslide area (Outer Western Carpathians), with a focus on the catastrophic event of May 2010. The study sought to understand how these species contribute to dendrogeomorphic reconstructions of landslide events, particularly by analyzing their growth responses and the frequency of growth disturbances (GDs) such as compression and tension wood. The results revealed significant differences in how P. abies and F. sylvatica responded to landslide activity. P. abies showed a higher frequency of GDs (compression wood), but exhibited greater inertia in its physiological response, potentially masking high-frequency landslide events. In contrast, F. sylvatica produced fewer GDs (tension wood), yet its response to landslides was more immediate and efficient, with 100 % intensity in tension wood formation, which helped create a minimum-noise chronology despite fewer identified events. The study highlights the advantages and limitations of both species in dendrogeomorphic research. While P. abies contributes more frequently to detecting landslide events, the inertia in compression wood formation can complicate the interpretation of rapid landslide movements. On the other hand, F. sylvatica, though less responsive in terms of GDs, provides a clearer and more precise landslide chronology. Future research should explore the physiological factors behind these species' different responses to enhance the accuracy of dendrogeomorphic reconstructions.