The spatial distribution of forest damage by using simple maps of the obse,wed needle/leaf loss from the sampling grid can easily lead to misinterpretations, because needle/leaf losses on sample plots are not representative for the surrounding area. Often it can not be decided if the localization of a single needle/leaf loss is due to a local trend or a random observation within the normal spatial variation. Geostatistical methods are applied in this paper to show the spatial distribution of needle/leaf losses based on the average needle/leaf loss of individual plots.
Geostatisrical methods are briefly described, with special emphasis on the construction of variograms. Applicability is shown on a data set of the Swiss forest damage assessments in 1986 and 1990.
Geostatistical methods are an ideal tool for epidemiological studies. By combining the spatial distribution of forest damages with other spatially related statistics, new relations in causal research can be found. The comparison of spatial distribution of several years can reveal significant short-term changes.