Ecological consequences of deforestation and afforestation on a post-arable land: Changes in the composition and structure of plant communities and transformations of oak-hornbeam habitats and soil

Abstract

The species composition and structure of secondary communities developed after deforestation in fertile oak-hornbeam habitats and afforestation of post-arable land from Tilio-Carpinetum and Melitti-Carpinetum circles in the Knyszyńska Forest have been studied. The analysis was based on 178 relevés made by Braun-Blanquet method, including 47 relevés of oak-hornbeam natural communities, 59 relevés of post-clear-cutting communities after deforestation and 72 releves of five secondary forest communities, 30-59 years old forming the first generation of trees on post-arable land. The types of habitats, types of soil and surface geological formations were identified, while soil samples were subjected to chemical analysis.            The degree of deterioration of secondary communities on post-arable land was found to be the greater the shorter the time from abandonment of agricultural use of a given area. As a result of former cultivation the soil has been degraded and the composition and structure of plant communities have been altered. The identified vegetation patches show changes characteristic of IV and V phase of degeneration and deformations manifested as cespitization, apophytization and bryophytization. The oak-hornbeam habitats represent the weakly (d) or strongly (D) degraded habitats, with the soil upper layer transformed by tilling into a ploughing horizon (Ap), with changes in the form of humus and considerable simplification in morphology of soil profiles