Аннотация:Species composition and community structure of Collembola communities under the crowns of single trees were studied in non-urban and urban environments in order to reveal their possible significance in spatial organization in open biotopes. In a natural environments single trees may play an important role acting as refugia for forest species as well as a normal habitat for some eurytopic meadow forms. In urban habitats, the effect of single trees on collembolan community organization is much weaker. The ecotone effects of single trees is also discussed.