Ellagitannin Content of Oak Wood as a Function of Species and of Sampling Position in the Tree

Abstract

The eight ellagitannins known to be present in oak wood (castalagin, vescalagin, grandinin, roburins A-E) and castalin and vescalin were characterized in the newly felled wood from several pedunculate and sessile oaks. Determination of these components by HPLC enabled us to establish the qualitative and quantitative potential of each individual tree and of each species. The two species oaks presented a high variability in all components between individual trees. The pedunculate and sessile oaks were not significantly different in their ellagitannin contents. In addition, the distribution of ellagitannins in the wood from pedunculate and sessile oaks was studied as a function of three parameters: sampling height in the trunk; age of the wood; and orientation of the wood in relation to the cardinal points. Each parameter induced variability in ellagitannin content. The age of the wood was found to be important. The effects of height and orientation were not statistically significant. The variations revealed in this study are attributed to two phenomena: aging of the wood, and the different proportions of tissue contained in the wood. The ellagitannin content of the stave wood that the cooper uses to produce barrels is, therefore, strongly influenced by the position of the stave wood in the tree.