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Gewählte Master / Diploma Thesis:

Nuria Guerrero Hue (2021): Snow avalanche activity above Innsbruck,Austria:a dendrogeomorphological approach.
Master / Diploma Thesis - Institut für Alpine Naturgefahren (IAN), BOKU-Universität für Bodenkultur, pp 115. UB BOKU obvsg FullText

Data Source: ZID Abstracts
Abstract:
Snow avalanches are natural disturbances that can cause damage to forests, endanger people and material assets. Knowledge of past avalanches is crucial for forest management, planning mitigation measures and risk prevention. By analysing the past growth of trees, both temporal and spatial reconstructions of avalanche activity in forests are possible. A dendrogeomorphological approach was used to study past avalanche activity in the Arzler Alm avalanche path above the city of Innsbruck (Austria). It is a well-documented avalanche path with several avalanche protection measures in place. Increment cores were taken from 104 damaged and undisturbed trees. Tree-ring widths from 45 coniferous trees were measured, a visual detection of possible avalanche indicators (traumatic resin ducts, reaction wood, callous tissue) was performed and a reaction class was assigned. For the period 1855 – 2019 a total of 1471 possible avalanche indicators were observed, of which only 0.5% were in the dormant or early earlywood positions of tree ring. A set of criteria was applied to detect potential avalanche years: a minimum of 5% of responding trees, at least three trees showed an indicator and there was at least one strong reaction. Few strong avalanche reactions were identified, because there were either not enough disturbed trees in specific years or they did not exhibit any spatial pattern attributable to a snow avalanche. Even though it was not possible to reconstruct past avalanche events, some tree rings exhibited avalanche indicators for some documented avalanche events (e.g., 1968 and 2019). Dendrogeomorphology is not suitable for every forested avalanche path, as exemplified here. In the Arzler Alm avalanche path it is attributed to a strong anthropogenic influence, which influences the availability of trees by removing affected trees or interferes and alters the avalanche indicators in tree rings.

Beurteilende*r: Scheidl Christian

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