Quantifying the Protective Capacity of Forests against Snow Avalanches

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Quantifying the Protective Capacity of Forests
against Snow Avalanches
Peter Bebi and Perry Bartelt Swiss Federal
Institute for Snow and Avalanche Research, SLF
Davos
IDRC 2008 Davos, August 2008
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• Mountain forests of the Alps an overview

Dischma 1927
Dischma 2005
Protection forests cover large areas (c. 25 of
all forests in CH) Qualtiy of protection is
spatially and temporally variable
IDRC 2008 Davos, August 2008
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• Mountain forests of the Alps an overview

IDRC 2008 Davos, August 2008
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• Mountain forests of the Alps an overview

Blowdown
Bark beetle
Fire
Avalanches
Disturbances may change protective effect
drastically

Management of mountain forests between
cost-efficiency and maximal risk reduction
IDRC 2008 Davos, August 2008
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Mountain forests of the Alps other
ecosystem services
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• How to quantify the protective
  capacity of forests against
• snow
  avalanches?

Avalanche Modeling with AVAL 2D / RAMMS
Quelle Gruber, Christen and Bartelt, SLF / WSL
IDRC 2008 Davos, August 2008
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• How to quantify the protective
  capacity of forests against
• snow
  avalanches?

RAMMS Rapid Mass Movements A modeling system for
natural hazard research and practice
Source Gruber, Christen and Bartelt, SLF / WSL
impact pressure (kPa)
Animated flow height (m)
max velocity (m/s)
IDRC 2008 Davos, August 2008
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• How to quantify the protective
  capacity of forests against
• snow
  avalanches?

Avalanche modeling for different forest
scenarios Evaluation of the protective
capacity of different forests.
Situation with forest
Situation without forest
red zone impact pressure gt 30 kPa blue zone
impact pressure lt 30 kPa
IDRC 2008 Davos, August 2008
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Risk damage potential
recurrence probability
Hazard map
Object map xHazard map
Andermatt (Switzerland)
Source M. Teich (SLF / WSL)
IDRC 2008 Davos, August 2008
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Valuation of ecosystem
goods and services
Combination of risk-assessment with the valuation
of other ecosystem services. Integration of
uncertainties (Bayes Networks)
Source Gret-Regamey 2007
IDRC 2008 Davos, August 2008
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Conclusions
Mountain forests are (by surface area) the most
important avalanche protection. Their value is
spatially and temporally variable and can be
calculated for each stand in a risk analyis with
the help of avalanche modeling. It would be
possible to support measures for risk reduction
in mountain forests more efficiently by linking
them closer to their ecosystem services (and
changes in space and time). More research is
needed for improved decision support in mountain
forests, including the improvement of existing
models, the combination of different ecosystem
services and uncertainty analysis in risk-based
methods.
IDRC 2008 Davos, August 2008
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Thank you for your attention!
Peter Bebi and Perry Bartelt WSL / SLF
Davos email bebi_at_slf.ch, bartelt_at_slf.ch
IDRC 2008 Davos, August 2008