The Riparian Forest Overlook Spur off the Twin Barns Loop Trail winds through alder and black cottonwood groves. The plants and animals of this forest must be able to survive tidal influences on the Nisqually River. This forest is one of the rare, naturally-occurring, deciduous riparian forests found in Western Washington. Drought or flooding, erosion or choking silt - all are common and the habitat can change rapidly. Tidal changes in the river and sloughs bring a twice daily wash of mixed salt and fresh waters, as well as rich life-giving organic matter called detritus. In order to cope in this habitat, animals may move to higher ground or employ evolutionary adaptations which allow them to swim in water; plants adapt in various way to survive periodic flooding while retaining moisture when the waters recede.

 

Along the east side of the Twin Barns Loop Trail is a Riparian Forest that is not tidally influenced because it is behind a dike. This area was once similar to the tidally-influenced riparian forest, but was logged, diked and farmed. Second growth trees now form a forest that includes native species such as red alder, black cottonwood and big leaf maple. Some snags (dead, standing trees) still remain in the forest and provide nesting habitat for swallows and forage for woodpeckers. Many of the understory plants are a mix of nonnative plants like the Himalayan blackberry and English ivy. This area is undergoing restoration work by Refuge managers, including cleaning, contouring and replanting with more native plants.