Abstract
Foliage content of biochemical compounds such as chlorophyll, nitrogen, cellulose, lignin or soluble phenolics can be used as one of the indicators of tree stress. However spectral property of soluble phenolic compounds have not been sufficiently analysed and their relationship with phenolics content in foliage has not been sufficiently described yet.
The goal of the presented analysis was to study how soluble phenolic compounds in Norway Spruce foliage samples affect their spectral properties, and to find wavelengths suitable for a determination of statistical relationships among quantitative spectral parameters derived from spectral libraries and phenolics contents determined in the laboratory. The relationships were tested for selected wavelengths, for the whole spectra and for selected indexes (BNA, BNC) using regression analysis and multiple stepwise regression.
Although any functional method or spectral index that could be applied successfully for the determination of soluble phenolic compounds content have not been found yet, the presented results are quite unique and contribute to investigations that have been infrequently carried out. In spite of the fact that the needle samples of different age and from different canopy levels were collected, low variability in a content of soluble phenolic compounds across the test sites was found and this may be the main reason why any general relationships have not been derived yet.