Twentieth-century expansion of floodplain forest in the context of channel transformation of Polish Carpathian rivers

Abstract

A considerable increase in forest cover that occurred in the Polish Carpathians over the 20th century (Kozak et al., 2007) reflected not only the increase in the proportion of forest on hillslopes but also on valley floors. In the second half of the 19th century, valleys of Polish Carpathian rivers were typified by a lack or only scarce occurrence of floodplain forest (e.g. Wyżga et al., 2012). This situation was also typical of other mountain areas in Europe (Kondolf et al., 2002; Rinaldi et al., 2013). The lack of floodplain forest in major river valleys in mountain regions resulted from the formation of wide, highly mobile river channels and the use of riparian areas for cultivation and grazing. In the 20th century, there was a significant increase in forest cover of the Polish Carpathians and at the same time, floodplain forest developed in the valleys of major Carpathian rivers. Forest encroached on higher parts of former river channels that were no longer disturbed by channel processes after channelization and/or channel incision resulting from gravel mining. The abandonment of the pastoral and agricultural use of riparian areas, especially in the second half of the 20th century, enabled the expansion of forest also on pre-channelization floodplains.