GROWTH OF YOUNG BEECHES (FAGUS-SYLVATICA L) IN AN EVEN-AGED, 18-YEAR OLD NATURAL BEECH REGENERATION

In an even-aged 18-year old natural beech regeneration, the growth of young plants has been analysed using only the main stem under 3 daylig ht intensities: full-light, half-light, and shade. The structure shows 3, 2 and 1 layers respectively under these light conditions (table I) . The variations in total height and root collar diameter had 2 compon ents in full-light and in half-light only, ie among- and within-layers (figs 1, 2 and 3). In full-light, the height variations were responsi ble for the differences among the layers and those of root collar diam eter for the differences within the layers, fig 1. In half-light the v ariations in height and root collar diameter were simultaneously respo nsible for the differences among and within the layers (fig 2). The st ructure appeared early with a single or several layer(s) (fig 8). The annual and multiannual growth exhibited 3 periods: establishment, diff erentiation, and regression or stabilisation, (figs 5, 6, 8 and 9). In full-light where differentiation is best between the layers, stratifi cation had an influence on the vigour of the seedlings and to some deg ree on their shape, but not in half-light (fig 10). The layers may be considered as reflecting social status in full-light where the height is regulated by stratification. The classification of seedlings accord ing to their total height over the 18-year period will be analysed in a subsequent paper.