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| Titel |
Plant uprooting by flow as a fatigue mechanical process |
| VerfasserIn |
Paolo Perona, Katharina Edmaier, Benoît Crouzy |
| Konferenz |
EGU General Assembly 2015
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| Medientyp |
Artikel
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| Sprache |
Englisch
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| Digitales Dokument |
PDF |
| Erschienen |
In: GRA - Volume 17 (2015) |
| Datensatznummer |
250112531
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| Publikation (Nr.) |
 EGU/EGU2015-12691.pdf |
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| Zusammenfassung |
| In river corridors, plant uprooting by flow mostly occurs as a delayed process where flow
erosion first causes root exposure until residual anchoring balances hydrodynamic forces on
the part of the plant that is exposed to the stream. Because a given plant exposure time to the
action of the stream is needed before uprooting occurs (time-to-uprooting), this uprooting
mechanism has been denominated Type II, in contrast to Type I, which mostly affect early
stage seedlings and is rather instantaneous. In this work, we propose a stochastic
framework that describes a (deterministic) mechanical fatigue process perturbed by
a (stochastic) process noise, where collapse occurs after a given exposure time.
We test the model using the experimental data of Edmaier (2014) and Edmaier
et al. (submitted), who investigated vegetation uprooting by flow in the limit of
low plant stem-to-sediment size ratio by inducing parallel riverbed erosion within
an experimental flume. We first identify the proper timescale and lengthscale for
rescaling the model. Then, we show that it describes well all the empirical cumulative
distribution functions (cdf) of time-to-uprooting obtained under constant riverbed erosion
rate and assuming additive gaussian process noise. By this mean, we explore the
level of determinism and stochasticity affecting the time-to-uprooting for Avena
sativa in relation to root anchoring and flow drag forces. We eventually ascribe
the overall dynamics of the Type II uprooting mechanism to the memory of the
plant-soil system that is stored by root anchoring, and discuss related implications
thereof.
References
Edmaier, K., Uprooting mechansims of juvenile vegetation by flow erosion, Ph.D. thesis,
EPFL, 2014.
Edmaier, K., Crouzy, B. and P. Perona. Experimental characterization of vegetation uprooting
by flow. J. of Geophys. Res. – Biogeosci., submitted |
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