Trajectory analysis of long-term changes in the nutritional status of a Scots pine stand

For the Scots pine (Pinus sylvestris L.) stand Pustert (Bavaria, Germany), the temporal change in its nutritional status as assessed by foliar analysis is analyzed using different techniques of statistical data evaluation and graphical representation. The procedures include new methods such as the development of adequate trajectories and their combination with an improved “Timmer and Stones graphical diagnostic system” as well as with a Principal Component Analysis (PCA). This mothod of data evaluation and presentation has several advantages: (i) It allows to visualize the dynamics of a multi-dimensional data set in two-dimensional graphs. Additionally, (ii) it provides a tool to easily identify various types of temporal changes in tree nutrition as e.g. nutrient insufficiency, luxury consumption, and dilution. Finally (iii), it enables the reader to distinguish quickly between non-systematic inter-annual variation, episodic cyclic changes, and systematic trends in the nutritional status of a forest stand.