The RVing Geologist explores the Northern California Coast and the mighty redwood forests.

Though Tony and Peggy both grew up in southern California, we have found great joy in living near and visiting the northern California coast. Coastal bluffs, pounding surf, and mighty redwood forests feed our souls.

Mountain Building

The north coast region of California is the most seismically-active region of the United States. The northernmost reach of the San Andreas is between Cape Mendocino and Eureka at the "Triple Junction,” where the American, Pacific, and the Gorda plates meet. North of Cape Mendocino the off-shore Gorda Plate glides under the North American Plate in what is called a subduction zone. This subduction forms the mountains of the northern Coast Range. Energy builds up along these fault lines, and is released in the form of earthquakes that can easily have a magnitude of 6.0-plus onshore and offshore.

Gray Whale Migration

Every year, about 20,000 gray whales travel 5,000 miles from the Arctic to the Baja Peninsula in the fall for calving, and back north in the spring to their northern feeding grounds. It’s just another of the north coast’s charms, to be able to view this majestic migration. 

Those Trees, Though!

The poem continues but this line I quote every time I’m in the redwoods. 

Claiming the fame as among the oldest living things on earth, and the world’s largest and tallest trees, respectively, the giant sequoias and California (or coastal) redwoods Sequoia sempervirens are both in the cypress family Cupressaceae. They share features such as cinnamon-colored bark, evergreen needle-shaped leaves, and seed cones. Their main distinguishing features are habitat and trunk shape. The  “fog zone” within 50 miles of the northern California and southwestern Oregon coast is the primary range for the California or coastal redwoods. However, they don’t like to be too close to the shoreline where there is too much wind and salt.

In comparison, giant sequoias are limited to an area less than 36,000 acres in the western Sierra Nevada mountain range in California. The giant sequoia has a huge trunk (up to 30 feet at the base) that tapers as it increases in height, whereas the diameter of the redwood trunk is similar from root to tip. 

Prior to logging and clearing activities, the redwoods’ range was an estimated two million acres. Now, less than 200,000 acres of old-growth redwoods remain.

Redwoods can grow, albeit slowly, from the thousands of teeny-tiny seeds produced annually in their little cones. Less than 5% of the seeds germinate, and the seedlings are often destroyed by infections, fungi, and predators. More commonly, young trees sprout from the base of a parent tree. Sometimes the parent tree will burn or otherwise die, resulting in a family of younger trees often called a fairy ring. The strong but shallow roots of these mighty trees reach outward up to 100 feet and the intertwine with roots of other nearby redwoods, holding each other up. 

California redwoods can easily reach up to 350 feet in height, straight as an arrow. By comparison, the Statue of Liberty is 305 feet tall, and look at how wide her base is! The long, straight trunk of the redwood is what makes the lumber so popular. That, and it’s resistance to termites and rot. One tree can provide lumber for up to a dozen houses.

Redwoods not only get water through their roots from the ground, but the foggy coastal air provides a source of water through their leaves. What’s not absorbed drips down to lower branches or to the ground. What an advantage not to have to pump hundreds of gallons of water up 300 feet every day! Fog also provides an advantage during drought when the ground doesn’t have enough water, and filters the sunlight that would otherwise cause evaporation.

Soil, Fire, and Ecology

The natural soil is derived from the Franciscan limestone, slate, chert, and schist base rock. Deep soils are formed by decomposition of fallen leaves and dead trees being recycled back in to the ecosystem.

Redwood trees are resistant to fire, especially after they are 20 or more years old. The bark on older trees is a foot or more thick and contains tannin which protects the trees from burning and from insect invasion. When fire or lightning hit redwood trees, if they don’t topple they can resprout. In fact, redwood trees are at least as likely to sprout from a parent tree as from a seed. The trees and other plants that do burn, provide nutrients to the soil that help the survivors. 

Ecologically, redwood forests filter trillions of gallons of clean, drinkable water every year. In addition they store at least three times as much carbon dioxide per acre as any other kind of forest. One grove in Humboldt Redwoods State Park contains the largest measured concentration of living material in the world. 

Where to Visit 

Most of the redwoods that remain are protected in forests and parks.  Oh, and in our back yard where happily we have three growing, though we are outside their typical range. We are lucky to have them with our warm temperatures and lack of fog! I suspect there were others, and likely one was felled to build our house, which is completely constructed of old-growth redwood. 

Big Basin Redwoods State Park in Boulder Creek south of San Francisco was established in 1902 and is California’s oldest state park. The park preserves more than 18,000 acres of California redwood trees. There are redwoods in the park that are more than 50 feet around and up to 2,000 years old. In August 2020, a lightning fire complex caused extensive damage to the park. While the park buildings and infrastructure were mostly destroyed, in an early survey most of the trees appeared to have withstood the fire. 

Muir Woods National Monument in Mill Valley is 558 acres of redwood forest within Golden Gate National Recreation Area, about 16 miles north of San Francisco. Explore by hiking trails or shuttle. 

Armstrong Redwoods State Natural Reserve in Guerneville includes a visitor center, self-guided nature trails, and a variety of picnic facilities. All of the main park features can be found along the Pioneer Nature Trail. This trail is a mile and a half long round trip, is ADA accessible and is mostly flat and level.  

The Skunk Train was formed support the logging industry in the 1880s. Starting life as the Fort Bragg Railroad, it is now known as the California Western Railroad or, affectionately, “The Skunk.” The train originally transported lumber, as well as workers and families to logging camps along the route. Fumes from gasoline engines and crude-oil stoves combined into a pungent odor; the train could be smelled coming before it could be seen. Now the Skunk takes tourists on a grand tour of the redwoods, with logging history told by the Conductor. 

Avenue of the Giants Highway on Old Highway 101 parallels Highway 101 for 31 miles from Garberville to Scotia through redwood groves. 

Humboldt Redwoods State Park has the largest remaining stand of virgin redwoods in the world. 

Hike the trails, meet the trees, ride the skytrain gondola, visit the museum, and shop for souvenirs at Trees of Mystery in Klamath. Also, take photos with Paul Bunyan and Babe the big blue ox. 

Drive through a Redwood Tree

Chandelier Tree in Leggett: our tradition over the past several years is to drive our new vehicles (all two of them) through the Chandelier Tree. Being the closest to our home base, these are the redwoods we visit most often. 

Shrine Drive-Thru Tree at Myers Flat was cleaved open naturally. This location also features two-story tree houses and a fallen giant with a drive-up ramp. 

Klamath Tour-Thru Tree sits atop a hill near Redwood National Park along the Klamath River.