Standortsabhängige Entwicklung von Sträuchern und Bäumen im Sukzessionsverlauf von brachgefallenem Grünland in Südwestdeutschland
In 1975 an experimental programme in Southwest Germany has been established for the study of extensive maintenance methods and the course of succession on fallow grasslands and will be continued for an indefinite period. It includes 14 experimental areas with different site conditions distributed all over the country. The development of trees and bushes on the undisturbed succession plots has been observed and mapped. Summing up the results, there are a few interesting aspects related to the site conditions. Soon after the start of the experiments, on some experimental areas could be observed a remarkable development of trees and shrubs. After almost 20 years dense and nearly 10 m high forests with annual growth rates of 60-80 cm have raised on the productive sites. Polycormons show distribution velocities of approximately 1 m per annum. On the dry and shallow rendzinas of the Swabian Alb occurred a longtime unnoticed invasion of ashes and common maples. In most cases they are growing through the stock just by now, because their shoots increase only a few cm per annum. On the sites with medium deep soils we may observe a comparably low dynamic of vegetation development combined with an only poor establishment of tree species, which show most moderate growth rates. On the same sites the development of polycormons with a distribution velocity of approximately 0.5 m/a must be considered as a rule.