Tree-ring-based reconstruction of high-magnitude snow avalanches in Piatra Craiului Mountains (Southern Carpathians, Romania)

ABSTRACT

Tree-ring analyses were applied in this study, in order to document the spatial–temporal distribution of the past snow avalanche activity along two adjacent avalanche paths in Piatra Craiului Mountains (Southern Carpathians, Romania). The dendrogeomorphic reconstruction performed on 235 Picea abies (L.) Karst. trees is based on the analysis of the effects related to the mechanical impact that snow avalanches had on trees, which resulted in growth anomalies (e.g. scars, callus tissues, onset sequences of tangential rows of traumatic resin ducts, compression wood, growth suppression and release). Tree-growth anomalies found in cores and discs led to the determination of 8 avalanche events within path (1), respectively 10 avalanche events within path (2) spanning the 1950–2016 reconstructed period. Within the paths, a minimum frequency of major snow avalanches was determined and their spatial extent was defined for each reconstructed event. The analysis of weather conditions for two of the events documented in archival records and reconstructed by dendrogeomorphic analyses revealed the role of freezing/thawing periods, combined with heavy snowfalls, in triggering major snow avalanches.

KEYWORDS:

• Snow avalanches
• dendrogeomorphology
• frequency
• Picea abies (L.) Karst
• Piatra Craiului (Romania)

Acknowledgements

We are especially grateful to the members of the Piatra Craiului National Park (Zărneşti) Administration for sampling permission, logistic support during field investigations and the information provided regarding historically recorded snow avalanches. The two anonymous reviewers are acknowledged for their insightful suggestions that improved the manuscript.

Disclosure statement

No potential conflict of interest was reported by the authors.

Notes on contributors

Olimpiu Traian Pop is presently researcher and the coordinator of the Laboratory of Dendrochronology at the Faculty of Geography, Babeş-Bolyai University, Cluj-Napoca (Romania). His research activities are mainly oriented toward the study of the natural/anthropogenic hazards and their influence on tree-growth/forest dynamics in mountain areas.

Anca Munteanu is a researcher at Faculty of Geography, University of Bucharest (Romania). She is currently involved in research activities focused on the assessment of snow avalanche activity and related hazards in the Carpathians.

Meseşan Flaviu is a PhD student at the Faculty of Geography, Babeş-Bolyai University, Cluj-Napoca (Romania). In the Laboratory of Dendrochronology he is involved in the research studies which focus on geomorphic processes as disturbance factor for trees (dendrogeomorphology) in mountain areas.

Ionela-Georgiana Gavrilă is a researcher PhD at the Laboratory of Dendrochronology and also at the Research Center of Geographical Hazards and Risks, Faculty of Geography, Babeş-Bolyai University, Cluj-Napoca (Romania). Her research is focused on mountain geomorphic processes and related changes in space and time, dendrochronology, natural hazards and risks.

Cosmin Timofte is a PhD student at the Faculty of Geography, Babeş-Bolyai University, Cluj-Napoca (Romania). In the Laboratory of Dendrochronology he is reconstructing the snow avalanche activity with tree rings in the Southern Carpathians.

Iulian-Horia Holobâcă is Associated Professor and the coordinator of the Laboratory of Remote Sensing and Earth Observation at the Faculty of Geography, Babeş-Bolyai University, Cluj-Napoca (Romania). His research is focused on climatology, remote sensing and glaciology.