Forests in the Bay Area range from massive old growth redwood forests to open, grassy oak woodlands. These forests are home to a wide diversity of plant and wildlife species. Ancient, cavernous redwood groves shade an understory of tanoak and California bay laurel, hazelnut, thimbleberry, western azalea wood rose, wild ginger, trillium, redwood sorrel, sweet coltsfoot, elk clover, and sword ferns. Northern spotted owls, coho salmon, banana slugs, and many other wildlife species make their home in the redwood forests. Oak woodlands made up of live oaks or valley oaks interspersed with grasslands provide an abundance of food for animals in the form of acorns and insects. Pine forests are also found in the parks in areas where soil conditions are right. Fire-dependent bishop pines intermingle with an understory of coffeeberry, huckleberry, salal, manzanita, and ceanothus. Douglas-fir forests include California bay, big leaf maple, California coffeeberry, California hazel, red elderberry, ceanothus, and poison oak. Other forest types include grey pines found at Pinnacles National Park, and mixed hardwood forests of bay, oak, and madrone.