Within-crown Variation of Sitka Spruce Polyphenols

Abstract

The variation in polyphenol concentration was studied in current year's shoots taken at different heights from young trees of Sitka spruce, and in 2-year-old branches taken from various parts of older trees. Polyphenol variation with shoot position was caused by variation in the ratio of leaf to stem material in the different shoots. In the older trees, polyphenol variation was small, but definite trends associated with height were found, particularly in the patterns of stilbene accumulation. The material showing minimum variation and having high stilbene levels, and hence being of most value for routine sampling, was 2-year-old lateral branches taken from the upper part of the tree. A comparative analysis of several provenances showed that this material furnished data compatible with those previously obtained from current year's shoots.