Regularities in the geographical distribution of durmast oak forests in Polissia

The regularities of geographical distribution and the current state of rare phytocoenosis are essential tasks of ecological research. The durmast oak forests of Polissia are such plant communities. The subjects of the study were the durmast oak forests of Volyn Polissia (Volyn region), Maly Polissia (Rivne region), and Central Polissia (Zhytomyr region). Field studies were conducted in 2008–2023. Phytocenotic descriptions were carried out on plots of 0.25 ha each. The edificator of these forests, the durmast oak Quercus petraea Mattuschka (Liebl.), is a stenotopic species of Pollisian flora, typical of specific ecotopes with warm microclimatic conditions on south-facing slopes and soddy-podzolic soils, formed on the eluvium of brim rocks (pink sandstones, limestone oolites, and moraine with granite boulders). In contrast to zonal oak forests formed by Quercus robur L., durmast oak forests are insular, extrazonal communities of Polissia. The Ovrutch-Slovechansky ridge, like Central Polissia in general, is a unique refugium of Tertiary relicts, including Q. petraea. Local populations of this species in Volyn Polissia, confined to moraine deposits, are apparently relicts of the Mindel-Riss interglacial. The same relicts are the sedge forests of Maly Polissia in the Ostroh Pass Valley, which were formed and shaped during the glacial period. As rare, relict, extrazonal communities, the durmast oak forests of Polissia are of considerable interest from a phytosozological perspective. The protection of durmast oak forests in Polissia is now sufficiently ensured. It only requires some improvement. Taking into account the value of gene pool of Quercus petraea near the eastern limit of its range in Europe, it is necessary to expand the afforestation efforts for this species in Ukraine.