9.2: North Coast

The North Coast of California, also referred to as the Redwood Empire or the Redwood Coast, due to the dense redwood forests throughout the region, is a region in Northern California that lies along the Pacific coast between San Francisco Bay and the Oregon border. It commonly includes Mendocino, Humboldt, and Del Norte counties and sometimes includes two counties from the San Francisco Bay area, Marin and Sonoma.

Figure 9.2: Location of the North Coast in California. Map of the North Coast region of California by Wikimedia User Cristiano Tomás is used under a CC BY-SA 4.0 license.

Physical Geography

The Pacific Ocean coast stretches from San Francisco Bay to Humboldt Bay and on to the border of Oregon. The coastline is often inaccessible, and includes rocky cliffs and hills, streams, and tide pools. The coastline from Centerville Beach near Ferndale to the mouth of the Klamath River is mostly beach accessible and there are many small towns and a few cities along Highway 101, the main route through the region. The sparsely populated interior territory further inland is characterized by rugged, often steep mountains, bisected by rivers and their typically narrow valleys and canyons, and dense redwood, Douglas fir, and oak forests. The climate can range from coast side lands drenched with fog in mild winters and summers to inland reaches baked by hot sunshine on long summer days, which, at higher elevations, can be blanketed with snow in winter.

The southern portion of the North Coast is largely urbanized while the rest is mostly rural. The more remote northern areas are often referred to as being located "behind the Redwood Curtain." A segment of the coastline in Mendocino and Humboldt Counties is known as the Lost Coast and is only accessible by a few back roads. Notable seaside beaches can be found at Marin Headlands and Point Reyes National Seashore in the south, with innumerable examples of remote or less used beaches north of the San Francisco Bay area.

The grandeur of the redwoods can be experienced throughout the region because of the fog. With the westerly winds that bring onshore flow from the cold ocean over the warm land creates advection fog that provides the moisture needed for these trees to thrive. From the protected groves of Muir Woods National Monument and Armstrong Redwoods State Natural Reserve in the south to the massive forests of Humboldt Redwoods State Park along the Avenue of the Giants in the north. Other larger redwood parks include Prairie Creek Redwoods State Park, Del Norte Coast Redwoods State Park, Jedediah Smith Redwoods State Park and Redwood National and State Parks. In total, the redwood parks of the North Coast contain most of all remaining old-growth redwoods.

Physical Geology

The Mendocino Coast is relatively young and is still actively uplifting. Landforms such as sea caves, stacks, and arches are common due to the cliff and headland erosion. When the roof of a sea cave falls, a bowl-shaped formation result. Other portions of the coast have rocks that look like bowling balls and gargoyles! Additionally, marine terraces reveal evidence of the history of uplift and erosion.

A sea arch is a natural opening eroded out of a cliff face by the action of wind and water. Sea stacks represent remnants of sea arches that have collapsed because of a continued wave erosion.

Because the northern California coast faces the Pacific Ocean basin, where strong earthquakes occur frequently, tsunamis pose an additional hazard. Tsunamis can travel thousands of miles from their source, so even earthquakes in Japan or South America have potential to affect the northern California coast. Coastal development is commonly at risk because of cliff retreat and mass wasting events that undermine support for structures.

The San Andreas Fault in Mendocino County is located pretty much right at the coastline. The San Andreas fault runs offshore near the town of Point Arena to Cape Mendocino, where the San Andreas Fault ends at the "Triple Junction.” The Triple Junction is where the American Plate, Pacific Plate, and the Gorda Plate meet. North of the Cape the offshore Gorda Plate glides under the North American Plate in what is called a subduction zone. This movement is what forms the northern Coast Range.

Figure 9.3: Map of the San Andreas Fault Near Tomales Bay. Image by Jeremy Patrich is licensed under CC-BY 4.0.

The mountains of the northern Coast Ranges are still rising due to continued plate movement at the Triple Junction. In the Mendocino area the land has been rising faster than the sea for thousands of years, resulting in marine terraces or steps. Because of continual uplift the terraces are elevated above sea level giving a staircase-like appearance. The result is an “ecological staircase.” Each terrace, or step, represents approximately 100,000 years and possesses a distinctive vegetation type. A trail leads through these steps at Jughandle State Reserve. From the 2.5-mile trail, five terraces and approximately 650 feet of elevation increase can be viewed. The trail spotlights the different ecosystems from coastal scrub and grassland; through pine, redwood, fir, and spruce forests; then through Mendocino (pygmy) cypress groves; up to pine, fir, and Fort Bragg manzanita woodlands; and finally, the oldest, highest terrace represented by Douglas fir forest.

The steep northern Coast Range intensifies rainfall due to the orographic effect. As Pacific storms hit the coast, air masses are forced up the steep mountainside. As the air rises, it cools, and water vapor condenses and concentrates rain on the coastal side of mountains.

Cultural Geography

The indigenous peoples of the Pacific Northwest Coast were composed of many nations and tribal affiliations, each with distinctive cultural and political identities. But they shared certain beliefs, traditions, and practices, such as the centrality of salmon as a resource and spiritual symbol. These nations had time and energy to devote to the establishment of fine arts and crafts and to religious and social ceremonies, compared to other inland nations since food was more plentiful and the climate was less extreme. The term “Northwest Coast”, or “North West Coast”, is used to refer to the groups of indigenous people residing along the coasts of British Columbia, Washington State, parts of Alaska, Oregon, and northern California.

The Pacific Northwest Coast at one time had the most densely populated areas of indigenous people. The mild climate and abundant natural resources, such as cedar and salmon, made possible the rise of a complex aboriginal culture. The indigenous people in this region practiced various forms of forest gardening and fire-stick farming in the forests, grasslands, mixed woodlands, and wetlands, ensuring that desired food and medicinal plants continued to be available using advanced farming techniques. Those involved in agricultural development would create low-intensity fires to prevent larger, catastrophic fires and sustain low-density agriculture in a loose rotation. This is what is known as permaculture, or any system of sustainable agriculture that renews natural resources and enriches local ecosystems.