Effect of species and ecological conditions on ellagitannin content in oak wood from an even-aged and mixed stand of Quercus robur L. and Quercus petraea Liebl.

Abstract

Species effects and ecological conditions on ten heartwood ellagitannins (vescalin, castalin, roburins A-E, grandinin, vescalagin and castalagin) and ellagic acid were investigated in a 100 years old stand of 5 ha located in western France (La Petite Charnie State Forest, Sarthe). The sample included a total of 286 trees (118 sessile oaks, 158 pedunculate oaks and 10 individuals with an intermediate morphology) located in three ecological zones (plateau, slope, small valley). The main factor influencing oak extractives level was botanical species. The ecological zone effect appears negligible. Pedunculate oak is generally richer in ellagitannins (48.4 mg/g against 34.4 for sessile oak), although a clear boundary between the two species cannot be established. Ellagitannin content was found to be correlated with ring width for pedunculate oak and not for sessile oak. The vescalagin/castalagin ratios differed between the two species (0.69 for Quercus robur against 0.53 for Quercus petraea). The distribution of ellagitannin contents is not strongly structured spatially. © INRA, EDP Sciences, 2006.