RESTER - Strategies to reduce the storm risk of forests

Background and Goals

The project is studying the influence of climate change on the severity and frequency of occurrence of winter storms and the anticipated effects on forest stocks in Baden-Württemberg. Comparison of the calculated future climate development with the reference period enables the effects on winter storms to be verified. Extreme value statistical methods are used on the data obtained to assess the potential damage to forest stocks for the current and future climate. Measures to prevent damage will be derived from this.

The objective of the combined project is to determine the influences and effects of global change on forestry at a regional scale. This will be done by formulating comprehensive risk maps for storm damage in forests and storm damage models relevant to forestry as a basis for methods to reduce storm damage in Baden-Württemberg's forests. The risk maps are based on all currently available information on the chain of causality for storm damage in forests. As a further basis, the mechanistic storm damage models available in the literature are being reviewed in terms of their applicability to the location and stock conditions in Baden-Württemberg and supplemented by a statistical storm damage model.

Content time

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Research area/region

Country
  • Germany
Region of implementation (all German federal states)
  • Baden-Württemberg
Natural spatial classification
  • Alp and North Bavarian hills
  • Alps
  • Alpine Foothills
  • Upper Rhine Rift

Steps in the process of adaptation to climate change

Step 1: Understand and describe climate change

Approach and results 

Climate simulations are carried out using the ECHAM5/REMO model and by comparing the reference period 1971 to 2000 with the forecast period 2021 to 2050 using the A1B emission scenario from the Intergovernmental Panel on Climate Change (IPCC). Detailed simulations using the German Meteorological Office's "local model very short timeframe" are carried out for selected storm events. In addition to the REMO regional climate model, two versions of the CLM regional model are being used to analyse the relative changes in storm activity. Two different versions of the global model have been used to drive the CLM simulations:

  • For the Northern area of Germany, REMO and CLM run 1 show a slight increase in gust speeds, while CLM run 2 does not;
  • In Central Germany, there is no clear trend for storm activity;
  • All models agree that hardly any change in the storm climate can be expected in Southern Germany.

The major differences in the CLM results with different versions of the global model indicate that the global model used to drive the simulations has a significant influence on the results at regional level. In addition, it is clear that these differences are greater than those between different regional models with the same driver.

The summary is that a realistic geographical representation of extreme gust speeds is possible using regional climate models. However, gust speeds are systematically underestimated. Future changes in the storm climate are shown to differ considerably by region. Overall, the only clear indication of an increase in storm activity between the control and projection period was identified in Northern Germany.

The differences between the models show that in order to obtain a sound analysis it is necessary to use not only a global and regional model but also to study so-called ensembles. The use of more detailed regional models represents an important step towards reproducing the wind structures observed in the model.

Parameter (climate signals)
  • Storm
Further Parameters 

Trends for climate variables and increasing frequency of extreme weather events, particularly winter storms

Time horizon
  • medium term = to 2050

Step 2a: Identify and assess risks - climate effects and impact

Approach and results 

The climate effect studied is the change in the risk of storm damage for Baden-Württemberg's forests.

Step 3: Develop and compare measures

Measures and/or strategies 

Background and objectives: More severe winter storms in particular could cause a rise in the levels of damage to forest stocks. Therefore, the development of preventive strategies to reduce storm damage and the risk of storm damage in forests is of major importance as part of preventive crisis management.

Time horizon
  • 2021–2050 (near future)

Participants

Funding / Financing 

Baden-Württemberg, in the framework of the research programme "Challenge of Climate Change"

Project management 

Meteorological Institute, University of Fribourg

Cooperation/Partners 

Institute for Meteorology and Climate Research, Troposphere Research (IMK-TRO), University of Karlsruhe;

Laboratory of Building and Environmental Aerodynamics, University of Karlsruhe;

support from Forstliche Versuchs- und Forschungsanstalt (FVA - forest research institute), Baden-Württemberg

Contact

Meteorologisches Institut der Albert-Ludwigs-Universität Freiburg
Werthmannstr. 10
D-79085 Freiburg

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Fields of action:
 woodland and forestry