Tree layer dynamics of the Cahnov-Soutok near-natural floodplain forest after 33 years (1973-2006)

The paper deals with the issue of the spontaneous development of Central-European floodplain forests. The research object was the Cahnov-Soutok National Nature Reserve situated on the confluence of Dyje R. and Morava R. in the Czecho-Slovak-Austrian borderland area. This locality has been left to spontaneous development since the beginning of the 1930s. In the years 1973, 1994 and 2006, the surveyed site was subjected to the measurement of standing and lying, live and dead trees reaching a diameter at breast height of 10 cm and the whole area regeneration of woody species. The work objective is to describe the most pronounced trends in tree layer changes having occurred in the period of study and to capture changes in the total tree volume and production of dendromass during the disintegration of the old grazing oak layer. The survey into the near-natural floodplain forest of Cahnov-Soutok showed that (1) the most significant trend is a decreased representation of Quercus robur in all monitored indicators and conversely an expanding representation of Acer campestre, Carpinus betulus and Tilia cordata and (2) that the floodplain forest ecosystem demonstrates a high-level stability in the total volume of tree biomass with an essential change in the tree species composition, spatial structure and average stem volume of individual trees.