Hydrogeomorphic activity in ungauged Mediterranean gorges: Specifics of tree ring data-based study

Abstract

Hydrogeomorphic processes (HP) are dangerous natural hazards, particularly in areas with increasing settlement. The Mediterranean region is a highly endangered area, particularly due to its high sensitivity to environmental changes. Chronological information about past events occurrence is crucial for modelling its development in the future. This study aims at building the chronology of past HP in two ungauged gorges along the southern coast of Crete using dendrogeomorphic methods. In total, 188 wounded trees revealed information about 13 events in nine various years over the past 80 years. Dendrogeomorphic records were obtained from Italian cypress (Cupressus sempervirens L.) – a tree species that has never before been used for palaeoflood analysis. Limitations of this species are presented and discussed. Moreover, the analysis of the growth responses of Italian cypress to HP events at the anatomical level resulted in important findings regarding its possible use for dating in the future. The reconstructed chronology of events expresses the number of HP events over past decades. The spatiotemporal patterns of affected trees suggest various characters of the process during individual events. Moreover, the type/character of the process is most likely changed even in the longitudinal profile of the gorges during the same event.