Integrating Analysis of monitoring data on crown condition, forest nutrition, soil condition and deposition in Baden-Württemberg

Dr. K. v. Wilpert, Department of Soil Science and Forest Nutrition, Dr. E. Kublin, Department Biometry und Computing, Forest Research Institute of Baden-Württemberg, Freiburg
Dr. N. Augustin, M. Meier, Dr. M. Musio,  Prof. Dr. M. Schumacher, FDM, Institute of Medical Biometry and Medical Informatics

• Summary and objectives

Since the 1980s the forest health status has been monitored in Baden-Württemberg using different survey schemes.  A number of different possible influential factors have been investigated. A justification for these monitoring programmes is the hypothesis that the current deterioration of forest health is of a chronic nature. The deterioration is meant to be caused by acidification and the washing out of essential alcaline macro nutrients in the root area which has a negative influence on forest nutrition and this finally causes the loss of needles and leaves. The hypothesis on the order of dependence is:
Nature and magnitude of deposition --> soil condition -->  forest nutrition --> crown condition.

The forest monitoring data on crown condition (defoliation), forest nutrition, soil condition and deposition of acidifying components are not available at the same spatial and temporal resolution. Hence in the first stage of the project the data will be interpolated using spatial and geostatistical methods. A main part of this task is the variance estimation of the predicted spatial surfaces and temporal trends.

The second stage of the project will entail exploratory statistical analysis of the biological processes causing tree deterioration. In particular the relationships between deposition, location attributes (e.g. height, aspect of slope), soil condition, forest nutrition and crown condition will be investigated.

The above tasks will be restricted to the Baden-Württemberg data.  Nevertheless it is envisaged that the developed techniques are general enough to allow their application to data from other federal states.

The main statistical and biological points to be addressed in the project are as follows:

• Interpolation of the available data in space and time.
• Estimation of the temporal trend (with confidence bands) of the tree health status in Baden-Württemberg incorporating the data on crown condition, forest nutrition, soil condition and deposition of acidifying components.
• Improvements of the current monitoring programme/ sampling design: e.g. Sampling of forest nutrition data is very time consuming and costly; surveys were only undertaken in three years since 1980. There is potential to optimise the sampling design in order to reduce costs and improve the data situation.