Quantifying the Protective Capacity of Forests against Snow Avalanches

Quantifying the Protective Capacity of Forests against Snow Avalanches

IDRC 2008 Davos, August 2008

Peter Bebi and Perry BarteltSwiss Federal Institute for Snow and Avalanche Research, SLF Davos

Mountain forests of the Alps – an overview

IDRC 2008 Davos, August 2008

Protection forests cover large areas (c. 25% of all forests in CH)

Qualtiy of protection is spatially and temporally variable

Dischma 1927 Dischma 2005

Mountain forests of the Alps – an overview

IDRC 2008 Davos, August 2008

Mountain forests of the Alps – an overview

IDRC 2008 Davos, August 2008

Disturbances may change protective

effect drastically

Blowdown Bark beetle

Fire Avalanches

Management of mountain forests – between cost-efficiency and maximalrisk reduction

Mountain forests of the Alps – other ecosystem services

How to quantify the protective capacity of forests against snow avalanches?

IDRC 2008 Davos, August 2008

Avalanche Modeling with AVAL 2D / RAMMS

Quelle: Gruber, Christen and Bartelt, SLF / WSL

Avalanche starting zones

Forest

Surface roughness

Conference Center Davos

Animated flow height (m)

impact pressure (kPa)

max velocity (m/s)

RAMMS: Rapid Mass MovementsA modeling system for natural hazard research and practice

Source: Gruber, Christen and Bartelt, SLF / WSL

How to quantify the protective capacity of forests against snow avalanches?

IDRC 2008 Davos, August 2008

Situation with forest Situation without forest

Avalanche modeling for different forest scenarios

Evaluation of the protective capacity of different forests.

red zone: impact pressure > 30 kPa; blue zone: impact pressure < 30 kPa

How to quantify the protective capacity of forests against snow avalanches?

IDRC 2008 Davos, August 2008

Hazard map

Object map xHazard map

Object mapx

Source: M. Teich (SLF / WSL)

Andermatt (Switzerland)

IDRC 2008 Davos, August 2008

Risk = damage potential * recurrence probability

Valuation of ecosystem goods and services

IDRC 2008 Davos, August 2008

Source: Gret-Regamey 2007

Combination of risk-assessmentwith the valuation of other ecosystem services.

Integration of uncertainties(Bayes Networks)

IDRC 2008 Davos, August 2008

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.

Conclusions

Thank you for your attention!Thank you for your attention!

Peter Bebi and Perry Bartelt WSL / SLF Davosemail: [email protected], [email protected]

IDRC 2008 Davos, August 2008