Old maps show that in medieval times riparian forests were widespread and covered over two thirds of the surface area of the Oder Valley. Agricultural development drove back the riparian forests further and further. Mowing, as well as trampling and grazing of livestock and wildlife, but also the absence of regular flooding, as a result of the canalization of the stream have kept new trees from coming up. Such floods would be needed to open up the thick blanket of vegetation and to give tree seeds carried in by wind and water the chance to germinate in erosion areas.
The hardwood riparian forest is dominated by elm and oak trees, located on wet ground in the riparian zone, and easily stands the winter floods. In the Lower Oder Valley the hardwood riparian forest consists mainly of fluttering elm (Ulmus laevis) and English oak (Quercus robur). A larger remainder of hardwood riparian forest can be found around lake Welse.
Floods in summer, during the growing period, are comparatively more difficult for hardwood riparian forests to cope with. The effects of the extreme summer flood of 1997 are well visible in the case of lake Welse. A great many elms and oaks died that year, with the dead stems still standing today. This is, however, a natural process which in turn opens up habitats for other forms of life.
Similarly, only in a few spots is there softwood riparian forest left in the Lower Oder Valley, for instance, as a grove of black poplar and white willow at Crieort, as well as in the areas before the dam by Lunow, and at the Old Oder. Softwood riparian forests are made up of different species' of willow and poplar, most commonly of:
- White willow (Salix alba)
- Purple willow (Salix purpurea)
- Eurasian aspen (Populus tremula)
- White poplar (Populus alba)
- Black poplar (Populus nigra)
The indigenous black poplar is extremely threatened, but with the help of a special project it is now experiencing a new, scientifically attended revival.
In the framework of current conservation management it is intended to increase the portion of riparian forest again. According to the foster- and development plan, reestablished riparian forests are projected to cover surface areas of up to 1000 hectares. This shall be achieved by initial plantings, which will open up the otherwise thick layer of weeds, and will after some years produce a self-sustaining riparian forest. Land tenants are encouraged to clearly demarcate riverbanks and groves in order to facilitate natural rejuvenation of the riparian forests.