TRAJECTORY ANALYSIS OF LONG-TERM CHANGES IN THE NUTRITIONAL-STATUS OFA SCOTS PINE STAND

For the Scots pine (Pinus sylvestris L.) stand Pustert (Bavaria, Germa ny), the temporal change in its nutritional status as assessed by foli ar analysis is analyzed using different techniques of statistical data evaluation and graphical representation The procedures include new me thods such as the development of adequate trajectories and their combi nation with an improved ''Timmer and Stones graphical diagnostic syste m'' as well as with a Principal Component Analysis (PCA). This method of data evaluation and presentation has several advantages: (i) It all ows to visualize the dynamics of a multi-dimensional data set in two-d imensional graphs. Additionally, (ii) it provides a tool to easily ide ntify various types of temporal changes in tree nutrition as e.g. nutr ient insufficiency, luxury consumption, and dilution. Finally(iii), it enables the reader to distinguish quickly between non-systematic inte r-annual variation, episodic cyclic changes, and systematic trends in the nutritional status of a forest stand. For the studied site, three major changes in the nutritional status of the Scots pine stand during the past 30 years could be identified: (i) a concomitant improvement of its N and P nutrition between 1964 and 1980 was observed, primarily reflecting the recovery of the ecosystem from past intensive litter-r aking and other exploitative forest utilization. We also recognized (i i) a trend rewards an unbalanced nutrient supply induced by excessive gains of the ecosystem in N compared to other major nutrients particul arly after 1980, which is probably due to elevated atmospheric N depos ition. In particular, we noticed (iii) a continuous dilution of the Ca concentrations in the foliage. Obviously, Ca uptake could not keep pa ce with the increased biomass accumulation.