1 Swiss Federal Institute for Forest, Snow and Landscape Research (WSL), CH-8903 Birmensdorf,
2 Paul Scherrer Institute, CH-5232 Villigen PSI, Switzerland
Twenty-four chemical elements were analysed by INAA, ICP-AES and CN in needles of Norway spruce (Picea abies (L.) Karst.). Branches were sampled from 54 trees on 8 sites in Switzerland and South Germany. From each tree, twigs were sorted into the most recent 4 or 5 age classes and their needles analysed separately.
All measured concentrations could be considered as log-normally distributed and statistical analyses were therefore performed on logarithms. Variance components were estimated by maximum likelihood and compared between elements. Non-essential elements varied more than essential nutrients (Mn was an exception). The sites and the age of the needles were the most important sources of variance. The interaction between site and age, the individual tree, the sampled branch and the residual variance were usually much smaller sources of variance.
The effects of the most significant factors ? site and age ? were further described by principal components and cluster analyses. Mineral elements either increased or decreased with the age of the needles according to their mobility in the phloem. Two different components were identified in the effect of the sites: a geochemical component linked to soil pH and a climate component linked to altitude, temperature and precipitation. Multivariate statistics are discussed as a tool for the interpretation of complex interaction patterns between element concentrations in plants.
Keywords: Norway spruce, Picea abies, needle analysis, nutrients, trace elements, multivariate statistics