Predicting intra- and intertree variability of wood density in sessile oak (Quercus petraea Liebl) through modelling earlywood and latewood width and density from cambial age, ring width and height in the tree.

The oak wood intraring density being considered as an important criterion of its quality, we studied ring microdensitometric components variability (earlywood density, earlywood width, latewood density, latewood width). First, we considered the intratree variation of density with cambial age, ring width and level in tree. We used regression methods to establish models of variation with the variables we had considered and we studied parameters of the different models (table II) by analysis of variance. Within a tree, we showed that earlywood width could be considered as a constant (fig I)and that earlywood and latewood density were only dependent on cambial age (fig 2). For ring width and cambial age given, the level in the tree effect was important only on the lowest level of our sampling (tables III and IV). We then studied intertree density variations on 24 trees collected in northeastern France (table I). We evaluated the site effect and the tree in site effect on the parameters of the models considered beforehand (table V). We found a 'site' effect and a 'tree in site' effect on some parameters; however, these results will have to be carefully assessed because of the relative weakness of our sampling. Nevertheless, we can confirm the important wood density variability between trees.