The process of secondary succession is observed in the meadows of river valleys in most areas of Central Poland. Abandoned meadows are the result of demographic and economic changes in the country. As a result of secondary succession, forest communities return to abandoned pastures in Pilsia Valley. There are several scenarios of this process. In the classical model the following sequential order appears: tall herbs, tall herbs with seedlings of trees and shrubs, willow thickets and woods. Drained meadows become secondary swamps. The transition stage of turning into a forest are rushes and nitrophilous climbers (Calystegietalia sepium). In the parts of the valley which are outside the direct reach of surface water, the return of the forest is preceded by the appearance of community with the dominance of one species, which is usually Deschampsia caespitosa.

37-47