Natural Features & Ecosystems - Redwood National and State Parks (U.S. National Park Service) Soils are composed of living and non-living matter, oxygen and water. Soils play an important role in regulating oxygen, carbon, nitrogen and hydrologic cycles, act as a filter by filtering out and storing contaminants, and provide habitat for billions of organisms, many of which are still unknown to science. The three large river systems within the park — the Smith River, the Klamath River, and Redwood Creek — have cut deep gorges through the forest and mountainous terrain. Redwood Creek follows the Grogan Fault northwest, with many small tributaries. The Klamath River, the largest in the North Coast region, provides important habitat for wildlife along its banks and in its estuary. The Smith River is also important for wildlife and has been named a Wild and Scenic River.