Typology and distribution regularities of oriental hornbeam shrubber- ies (Carpineta orientalis) in Tbilisi environs

Abstract

Oriental hornbeam formation (Carpineta orientalis) of Tbilisi environs is studied for the first time. Oriental hornbeam shrubbery is one of the characteristic and prevalent formations of Tbilisi environs. Tbilisi environs area of oriental hornbeam formation mostly include foothills and lower mountain belt at about 600 to 1000(1100) m above s.l., rarely is in middle mountain belt (1100-1300 m above s.l.). Its plant communities with different plots area are fragmentary spread mostly on Saguramo-Ialno ridge and east endings of Trialeti ridge; they also meet on Skhaltba low range. Plant communities are developed on slopes with various exposure and inclination, on the cinnamonic and brown forest soils. Sometimes soil is thin and skeleton, rarely with bare mother rocks. Formation is characterised by rich typological composition. 8 plant communities were identified by us: (1) Querceto-Carpinetum graminoso-mixtoherbosum, (2) Carpinetum graminoso-mixtoherbosum, (3) Carpinetum mixtoherbosum, (4) Carpinetum poosum nemoralis, (5) Carpinetum poo- so-caricosum, (6) Carpinetum caricosum humilis, (7) Carpinetum caricosum digitatae, (8) Carpinetum ruscosum. Their phytocoeno)- logical characteristics are presented. Geo-botanical descriptions are represented for each community in the form of consolidated table, in which are given general geo-botanical characteristics (general projective coverage, sodding degree, density, projective coverage, distribution and average height of each layer, floristic composition, coenetic role of each species - projective coverage, and etc.). Physical-geographical conditions (altitude, relief, exposure, inclination) are also given. In Tbilisi environs oriental hornbeam plant communities are secondary origin and derived as a result of digressive successions of oak forest (Querceta iberici).