If the river does not re-circulate the area, after a few tree generations, other tree species can establish themselves on the mature wetland soils. One of the first is often the white poplar, which can quickly take over new sites through root sprouts. White poplar forests therefore often form the transition between softwood and hardwood riparian wetlands. More demanding tree species such as oak, maple, ash and lime form the so-called hardwood riparian wetland.
This is no longer flooded frequently, but is still strongly influenced by the stream. Their locations are strongly influenced by the fluctuations of the groundwater flow that accompany the high and low water events of the Danube.
In the riparian forests of the National Park, highly endangered tree species are still locally very common, e.g. white willow and black poplar. Many specialised creatures also have their habitat here, such as beetles and their larvae in the deadwood of trees and shrubs. The stands of old trees are of great importance for bird life.
There is no longer any forestry use in the forests of the national park, only small-scale renaturation measures. These enable the forests in the protected area to develop rapidly into near-natural habitats again after decades of use and transformation by humans. The only woodcutter that is allowed to stay is the beaver.