In some places on the steep banks of the Nemunas and its tributaries there are habitats protected on a European scale – sloping forests and ravine forests. They consist of mixed forests with linden, maple, oak, elm, willow and ash. Spruce may be found on the north-facing slopes. In such forests, the impact of human activities tends to be small, as steep slopes and poor accessibility make timber extraction difficult. Species diversity is enhanced by springs and spring streams, rock outcrops and rocks in the beds of small creeks that form streams.