Natural Features & Ecosystems. Natural Features & Ecosystems - Redwood National and State Parks (U.S. National Park Service) Today, park staff is again using fire to maintain the oak woodlands, grasses, and other native plants found in this diminishing natural community. Fire not only helps preserve the natural values of these grassy expanses, but the cultural values as well. Values represented by the historic barns, relict stands of oak, and the openness of the land itself.