Growth variation of pedunculate oak trees (Quercus robur) in comparative cultures of different origin

At the age of 16, were analysed the comparative cultures of pedunculate oak, which have as seed sources the stands from the north, center and south of the Republic of Moldova. The provenances from the center area demonstrated a high adaptation capacity in the test site from the ,,Plaiul Fagului” reservation, having a signifi cant performance of growth in height than those from the south of the country. At the provenances studied, was observed the instability of the phenotypic variability, which resulted in the change of ranking regarding their growth in different years. This fact suggests that the genetic expression of growth in height occurs gradually, stadially, in the ontogenetic process of tree development. Also, is evident a strong hereditary infl uence of the oaks of origin on the growth rate of the descendants. The use of acorns within the limits of a forest body is risky with the reduction of the genetic diversity of the natural population. Under the conditions of climate change, the transfer of reproductive forest materials within the limits of the Central Moldavian Plateau can be admitted because the pedunculate oak has a vast genetic variability in terms of traits important for adaptation. The assisted migration within the limits of the center area to the oak, a species with a long life cycle and vast genetic variability, is justifi ed by the fact that natural selection will speed up the adaptation process of trees with the prediction of climate changes.