Regionalization WZE

Background and Objective

The WZE annually records the vitality status of forest trees. Since 1984, the data collection has been carried out nationwide on a representative sampling network (Level I monitoring) and allows the evaluation of crown defoliation (needle/leaf loss) and tree mortality at the federal and state level for the most important tree species in Germany. Due to the increasing stress on forests caused by climate change, wall-to-wall maps of these parameters are needed, which can be used to make statements about individual regions and forest stands, even between sample points. In this project, the statistical correlations between a wide range of environmental influences and tree vitality will be investigated using WZE data. These correlations can then be used to derive predictions for all forest sites in Germany.

Approach

Wall-to-wall maps are available for many different environmental variables, all of which could have an influence on tree vitality. First of all, these are the topography and soil properties. Furthermore, weather and especially deviations from the long-term climate mean (e.g. droughts) are considered. Various remote sensing techniques provide information on forest structure, species composition, and disturbance events. All these factors are examined for their influences with regard to vitality using the long time series of the WZE. For this purpose, methods from the fields of machine learning and geostatistics are used, which can then be used to create maps for the whole of Germany.