Transcript Quantifying the Protective Capacity of Forests against Snow Avalanches

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
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
Mountain forests of the Alps – an overview
IDRC 2008
Davos, August 2008
Mountain forests of the Alps – an overview
Blowdown
Fire
Bark beetle
Avalanches
Disturbances may change protective
effect drastically
IDRC 2008
Management of mountain forests –
between cost-efficiency and maximal
risk reduction
Davos, August 2008
Mountain forests of the Alps – other ecosystem services
How to quantify the protective capacity of forests against
snow avalanches?
Avalanche Modeling with AVAL 2D / RAMMS
Avalanche starting zones
Surface roughness
Forest
Conference Center Davos
Quelle: Gruber, Christen and Bartelt, SLF / WSL
IDRC 2008
Davos, August 2008
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)
max velocity (m/s)
IDRC 2008
Animated
flow height (m)
Davos, August 2008
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 > 30 kPa; blue zone: impact pressure < 30 kPa
IDRC 2008
Davos, August 2008
Risk = damage potential * recurrence probability
Hazard map
Object map x
Hazard map
Object map
x
Andermatt (Switzerland)
Source: M. Teich (SLF / WSL)
IDRC 2008
Davos, August 2008
Valuation of ecosystem goods and services
Combination of riskassessment
with the valuation of other
ecosystem services.
Integration of uncertainties
(Bayes Networks)
Source: Gret-Regamey 2007
IDRC 2008
Davos, August 2008
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
Thank you for your attention!
Peter Bebi and Perry Bartelt WSL / SLF Davos
email: [email protected], [email protected]
IDRC 2008
Davos, August 2008