Résumé
The radial variation of wood properties, especially within the juvenile transition, exhibit patterns typical of the species, with, however, a strong dependence on growth conditions. Data obtained on beech (Fagus sylvatica L.) from several high forest stands in European countries have been revisited with a focus on this aspect. Laboratory measurements of ring width (RW), wood specific gravity (SG) and wood specific modulus (SM), were used to examine aspects of juvenility corresponding to young stages of the tree. The radial variations of RW, SG and SM, averaged over 86 trees, were close to the “typical radial pattern” of juvenile wood for softwood plantation trees: decrease in RW and increase in SG and SM from pith to bark in the juvenile phase. But SG only increased in the very first rings, then remained more or less constant. Furthermore, for all three parameters there were many discrepancies in the pattern of variation between trees and between plots. This is a good indication that the mechanical juvenility of the wood was more related to the mechanical conditions experienced by the trees in the young ages than to the age of the tree as such, as is the case for other features such as fibre length. Moreover, no significant influence of red heart occurrence on wood properties was observed.