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

After a forest site classification, 3 forest sites characterised by distinct ecological conditions, where the pedunculate oak is largely present have been selected to study site factors' influence on the intra-ring wood density components (ring average density, earlywood and latewood density) considered as wood quality criteria for this species. These parameters have been collected by a nondestructive mean based on the microdensitometric analysis of increment cores extracted from 105 trees chosen according to a 3-stage sampling (3 sites, 7 stands into site, 3 trees into stand). This analysis has also provided the total width, 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 age is fixed and when cambial age and ring width are fixed the variation of wood density parameters result in large part, from an important intertree variability However, forest site influence on wood density parameters is significant and it seems that site factors act on the anatomic wood characteristics.