Probably the most unmistakable signs of the beaver's return are neatly gnawed tree trunks on water. Due to its semi-aquatic way of life, it needs trees, especially softwoods such as willows and alders, which it turns down to get to the branches. He then gnaws these off to build dams to design his building and from the bark he gets his winter fodder.
By felling trees and damming the water, the beaver has a great design effect on the landscape.
By creating dams, the beaver has fundamentally intervened in the structure of the stream. A new dynamic is developing in the monotonous flowing water. A multitude of different habitats are created; deep water points directly at the dam, shallow and slow-flowing sections enriched with mud above, fast-flowing water below the dam. Due to the high water level in places, the water gets rid of its sludge in the vegetation, making it clearer. The gnawed dead wood is deposited in places and forms protection for the fish fry, but also nesting places for birds. The alternation of gnawed trees and sprouting wood rejuvenates the bank vegetation and leads to a mosaic of different living conditions.