Big Basin Redwoods State Park, located about 23 miles northeast of the city of Santa Cruz, is not in a true basin. Formed millions of years ago by the uplifting of its circular rim and the eroding of its center by stream action, this bowl-like depression in the Santa Cruz Mountains has as its only outlets the forks of the Waddell Creek, which have cut deep gorges in the rim.

Climate
The climate in the basin is moderate with summer fog in the early morning and an occasional winter snowstorm. It is the ideal climate for redwoods.

Vegetation
"Sempervirens", meaning ever-living, is an ancient species of redwoods that has no major enemies except intense fire and saw-blades. One of the most impressive stands of virgin redwoods in the park is located on the Redwood Nature Trail. Beside the redwoods are Douglas fir, tan oak, California laurel, and wax myrtle trees. While the towering height of the redwoods, which may reach over 300 feet, shades out most understory shrubs, huckleberry, western azalea and several varieties of ferns are able to thrive in all but the densest stands. Many varieties of wild flowers appear during the spring, including redwood sorrel, salal, wild ginger, trillium, redwood violet and milk maids. Several varieties of wild orchid, while rare, are also found in Big Basin. In fall and early winter, the redwoods are a fungi-lover's paradise. Craters, sometimes involving as many as 10 or 12 trees in a circle surrounding a sunken spot or stump, are one of the chief methods of reproduction of the redwoods.

Acting as a transition between the redwood community and the chaparral of the drier, higher locations, the mixed evergreen community is composed generally of close stands where trees may reach 100 feet. They include madrone, coast live oak, California hazel, tan oak and Douglas fir. These areas support an abundant assortment of flowering plants: ceanothus or California wild lilac, Douglas' iris, hound's tongue, Indian warrior, Henderson's shooting star, and two-eyed violets.

The chaparral community is commonly found on south-facing slopes and dry, rocky ridges above the cloud layer. The plants of the chaparral are thick, non-yielding types of vegetation, mostly 3-7 feet tall. Toyon, coffeeberry, ceanothus, manzanita, chaparral pea, coyote bush and chamise are all well adapted to these drought conditions. Knob-cone pines, chinquapin, and buckeye provide the taller cover. Common chaparral wildflowers include the monkey flower, Indian paintbrush, California fuschia, bush poppy and yerba-santa. This community is actually a variation of the redwood forest community. It also contains more moisture-loving plants such as elk clover, western coltsfoot, horsetail, and five-finger fern along with big leaf maple and red alder trees.

Along the lower reaches of the Waddell, where the Douglas fir forest has ended, the streamside vegetation is dominated by willow, instead of alder. Near the mouth of Waddell Creek, in the Rancho del Oso section of the park, is the Theodore J. Hoover Natural Preserve. It is a freshwater marsh and is one of the few relatively undisturbed bodies of fresh water left along the coast.

Wildlife
Black-tailed deer, gray squirrels, chipmunks and raccoons are the most common mammals that one might see. Less noticeable are skunks, opossums, bobcats, foxes, coyotes, and mountain lion. There are no longer any grizzly bears in the Big Basin; the last sighting was in the late 1800's.

While there are few fish in the streams, this area is alive with reptiles and amphibians. Big Basin is home to the California newt, Pacific giant salamander, Pacific tree frog, the western skink, the western toad, the western fence-lizard and the alligator lizard. The rattlesnake is the only poisonous snake in Big Basin and is usually found in the drier chaparral regions. Non-poisonous varieties include California garter snakes, coast mountain king snakes, gopher snakes, Pacific ring-necked snakes and rubber boas.

Big Basin's bird life is rich and diverse. In the redwoods, you can find the ever-present Steller's jay, the vibrant and noisy acorn woodpecker and the dark-eyed junco. Less obvious are the brown creeper, the California quail, the northern flicker, and the American dipper. Big Basin was the location of the first sighting of a nest of the marbled murrelet, a web-footed shorebird which nests 200 feet high in the redwood forest. In the more open mixed evergreen and chaparral areas, red-tailed and sharp-shinned hawks are often visible, as are turkey vultures. Hummingbirds, owls, swallows, great blue herons, doves and warblers all inhabit the park.