A NEW ATTEMPT AT DISCRIMINATION BETWEEN QUERCUS-PETRAEA AND QUERCUS-ROBUR BASED ON WOOD ANATOMY

The interspecific variability of wood anatomy between the two major oa k species Quercus robur L. and Quercus petraea (Matt.) Liebl. is still largely unknown. However, anatomy strongly influences the technologic al properties of wood and the ecophysiological functioning of trees. M oreover, identification of oak wood species is a long-standing challen ge and important for many purposes. In the Citeaux Forest (Burgundy), 58 oaks from 14 mixed stands were sampled for wood anatomy characteriz ation. image analyses of four ring radiographies per tree were carried out. Shape, size, and proportion of tissues (earlywood vessels, fiber , parenchyma, and latewood vessels) were characterized, taking into ac count cambial age and ring-width effects. Taxonomic status of the tree s was assessed by foliar morphology analysis. Significant differences in numerous anatomical features appeared between the two species. The surface proportion of earlywood vessels (the proportion of total ring surface area taken up by these vessels), the number of earlywood vesse ls, and the size and surface proportion of fiber zones were among the largest. The diameter and shape of earlywood vessels did not differ be tween the two species. A bivariate discriminant function reached a 78% rate of success for species recognition. However, a much clearer foli ar morphology gap existed between the two species. At the intraspecifi c level, linear correlations between anatomical and morphological vari ables were significant for a few variables only. Nevertheless, for eac h species, trees displaying an atypical wood anatomy were also less mo rphologically representative. Technological and ecophysiological impli cations of these results are discussed. In mixed stands, hybridization introgression between the two species could explain the large anatomi cal overlap. Thus, anatomical discrimination between the two oak speci es may be easier in pure stands. Finally, a practical identification k ey is given.