Most of the 702-acre park is undeveloped. Forested areas feature one of the last remnants of old-growth Douglas fir forest in the lowlands surrounding Puget Sound. Park managers allow dead trees – called snags – to stand, in part because they provide habitat for rare pileated woodpeckers and other wildlife.
A 25-acre area on the southwest slopes of the park, near Fort Nisqually, also is home to an unusual plant community. It consists of old-growth Pacific madronas, Douglas fir, evergreen huckleberries and salal. The site has been recognized by the Washington Natural Heritage Program as one of only four places in the state where the plant grouping persists.