RELATIONSHIP BETWEEN FOREST SITE AND INTR A-RING WOOD DENSITY COMPONENTS FOR THE PEDUNCULATE OAK (QUERCUS-ROBUR L) OF SOUTHWESTERN FRANCE

After a forest site classification, 3 forest sites characterised by di stinct ecological conditions, where the pedunculate oak is largely pre sent have been selected to study site factors' influence on the intra- ring wood density components (ring average density, earlywood and late wood density) considered as wood quality criteria for this species. Th ese parameters have been collected by a nondestructive mean based on t he microdensitometric analysis of increment cores extracted from 105 t rees chosen according to a 3-stage sampling (3 sites, 7 stands into si te, 3 trees into stand). This analysis has also provided the total wid th, the width of the earlywood and latewood and age (position from the pith) of the 8 793 rings studied These data have been treated by a 3 hierarchised classification factors (site, stand into site, tree into stand) variance analysis. The results have shown that, when cambial ag e is fixed and when cambial age and ring width are fixed the variation of wood density parameters result in large part, from an important in tertree variability However, forest site influence on wood density par ameters is significant and it seems that site factors act on the anato mic wood characteristics.