Abstract
Extensive forest areas decreased and fragmented during anthropogenic development of the zone of broad-leaved forest tree species in Russia. The pedunculate oak (Quercus robur L.) and the European white elm (Ulmus laevis Pall.), important key components of these ecosystems, suffered last few centuries of extreme climate events, attacks of insects and diseases. Using ISSR genetic markers, we compared expected heterozygosity and allelic diversity of these two species in natural and artificial stands, planted and naturally regenerated progeny. Weak differences in the genetic diversity in Q. robur and U. laevis were revealed in areas with different forest cover and participation of the species in a stand composition. Overall, we found that the genetic diversity of parent natural and artificial stands is well reproducing in natural offspring and planted saplings. But the tree species studied express both higher and lower heterozygosity in planted trees in comparison to natural stands.