Analyse des composantes de la croissance en hauteur et de la formation du tronc chez le chêne sessile,<i>Quercus petraea</i>(Matt.) Liebl. (Fagaceae) en sylviculture dynamique

Abstract

Simultaneous observation of morphological and anatomical markers allowed us to reconstitute the growth pattern of the main axis in two populations of sessile oak aged 15 and 29 years, respectively. The comparison of the morphological features of annual shoots and growth units according to either their ontogenic age or their year of formation allowed us to separate endogenous trends in the development of the tree and variations resulting from the effect of annual growth conditions. Three stages of tree development were identified. The first stage is characterized by the regular production of monocyclic annual shoots with a stable mean length and is typical of young trees growing under a dense canopy. In the second stage of development, the intrinsic growth pattern expresses itself dominantly; this stage is marked by a systematic increase in the length and polycyclism rate of successive annual shoots, and by a strong differentiation between the successive growth units of polycyclic annual shoots. In the third stage, environmental factors have a stronger influence on the ontogenic growth pattern. In this stage, the length of the different growth units and annual shoots is stationary but shows important annual variations, while the differentiation between the successive growth units of bicyclic annual shoots is not systematic.Key words: Quercus petraea, sessile oak, morphology, primary growth, ontogeny.