Redwoods are giant trees that grow in cool temperate regions of the world. They get their name from their thick red bark. There are three species of tree in the redwood family:

• Sequoia sempervirens - the coastal (or coast) redwood
• Sequoiadendron giganteum - the giant redwood
• Metasequoia glyptostroboides - the dawn redwood

This Entry is about just one of these, Sequoia sempervirens, the coastal redwood. Sempervirens means 'evergreen', and Sequoia is named after a Cherokee man (1760 - 1843) of the same name who invented a system for writing down the Cherokee language.

Millions of years ago these trees were common in Europe, Asia and North America. Today, they are confined to the west coast of North America, from central California up to southern Oregon - except for a few specimen trees planted by gardeners in other places, where they are known by the name Wellingtonia.

The coastal redwood is the tallest tree, and the tallest living thing on Earth. The biggest are more than 360 feet high¹. To put that in perspective, the coastal redwood is the same height as St Paul's Cathedral in London, or slightly higher than the Statue of Liberty including its pedestal. Despite their height, they are not the biggest trees. The giant redwood has a thicker trunk and can contain more bulk, although it is not as tall.

Coastal redwoods usually have a single central trunk which goes straight up to the top of the tree. There are very few branches down low — in the tallest trees, the lowest branch may be 180 feet off the ground.

They are long-lived plants, regularly reaching 600 - 1,200 years old, with some specimens over 2,000 years old. In addition, an old tree can produce lumps around its base (known as burls) that can grow into new trees. Later, the original tree dies, falls and rots away, leaving a circle of new trees. These are genetic clones of the original and could be said to be still the same tree, extending the effective life of the tree to many thousands of years.

The trees need a lot of water and survive on fog — their upper branches like to be soaked in it. This is because it is difficult to pump water up from the roots to the high parts of the tree, so the upper branches absorb their moisture directly from the fog. In addition, excess fog condenses on the higher branches and drips down, watering the ground around the tree, so the roots get extra water, too. Therefore, coastal redwoods only grow within 50 miles of the Pacific Ocean and at elevations of less than 2,000 feet, which is about the limit of how far ocean-born fogs travel inland.

Coastal redwoods have been growing in California for 180 million years. The Native Americans tended to leave them untouched. They didn't have the technology to cut them down easily and, as they considered them the homes of evil spirits, stayed out of redwood forests. There is, however, at least one tribe, the Yurok, which uses the trees, making dugout canoes from redwood logs, and smoking salmon and sturgeon on redwood stakes.

The immensity and age of these trees is genuinely humbling — making the works of man seem insignificant. Visitors may report the experience of just standing in a forest of these trees as one of the highlights of a trip to this part of the world.

Survivors

You don't live to be a 1,000 years old without being good at surviving. Redwoods are supremely good at resisting all sorts of attacks:

• Their bark, up to a foot (30cm) thick in places, protects them from forest fires.

• Their wood is resistant to being water-logged, even in acidic water. It was actually used in the construction of car batteries at one stage because of this property.

• The wood contains tannins that discourage insects such as ants and termites from boring into the tree.

• Over centuries, floods can spread mud over the forest floor, causing the ground level to rise. This is bad news for most plants; they can't function if their roots are too deep. Redwoods just grow new lateral roots higher up the trunk. One fallen tree was noted to have survived a rise in ground level of 30 feet over its 1,000-year lifetime.

• If a redwood falls prematurely, perhaps in a storm, it can send new shoots upwards and downwards along the length of its trunk. These develop into new trees which are clones of the original. The original tree then rots away, leaving a line of trees in the forest.

• Young redwoods and shoots grow very quickly. They can achieve eight feet of growth in the first season alone, and can reach heights of 65 feet in the first 20 years.

• Despite the name 'coastal', redwoods don't like salt. They are damaged by ocean spray, so don't grow right down to the shore. There is a buffer zone of sitka spruce, alder and other salt-tolerant trees which gradually gives way to the full redwood forest.

Logging

When Europeans arrived in California they started to chop down the trees for wood. Loggers used axes or giant two-man saws, and most of the coastal region was cleared. The giant logs were hauled by oxen down makeshift tracks through the forest covered in greased planks. These tracks were known as 'skid rows'.

The lumberjacks quickly noticed that the trees widen considerably at their base. At a height of 15 feet off the ground, the tree may be only half the diameter it is at ground level, making it four times as easy to saw through. Losing 15 feet off the length of a 300-foot tree is not very significant, so the loggers tended to cut them at this height, leaving a 15-foot stump. They did this by cutting a slot in the tree about five feet up, putting a plank in the slot, standing on this plank, then cutting another slot, and so on.

Within a century, 96% of all the old-growth redwoods had been felled. Public opinion is now against the loggers. In 1998-99, campaigner Julia 'Butterfly' Hill staged a sit-in protest against logging, living for two years on a platform high in one of the redwoods.

Tourism

Nowadays, the only logging carried out is on land owned by timber companies, on second- and third-growth trees which have grown from the roots of already-felled redwoods. The virgin forests are no longer felled, but preserved as a natural amenity. There are about ten state parks in California consisting of redwood forests, as well as a few state natural reserves.

The state parks allow people to study the trees, trying to find out as much as possible about them. There are also visitor centres, tourist trails and campsites so that as many people as possible can visit the redwood forests in an environmentally-aware way and experience these amazing trees.

There is also a more commercial, old-fashioned and, it has to be said, more American form of tourism. Anything notable in a tree at all is picked out and made an object of amazement, with an obligatory gift shop next door selling carved wood bears and other redwood mementoes. In this category must be placed Confusion Hill, One-Log House, the Chandelier Drive-Thru Tree and much of the attractions at Trees of Mystery. Despite the immensely tacky feel to these presentations, there is something to be gained from visiting them, so we'll describe some of them here.

The Avenue of the Giants

One of the best ways to see the redwoods is to drive along the 'Avenue of the Giants'. This is a 31-mile stretch of road along a river valley which has been bypassed by the building of a much bigger road. Originally this was Highway 101, joining San Francisco to north-west California. Now the pace is much slower on the 'avenue'. The road is almost entirely under the trees and you can stop to look at them in any of the many lay-bys. There are a number of small towns along the avenue where you can buy refreshments, too.

Humboldt Redwoods State Park

This park is the biggest of the state parks devoted to redwoods, with 52,000 acres of forest and 17,000 acres of 'old growth redwoods'. The term 'old growth' means natural unlogged forest with a range of trees from very young all the way up to the full 2,000 years old.

I've never been so impressed with nature as I was standing in a redwood forest. There was utter stillness, the only sound being the drip, drip of the rain. The trees seemed to go right up into the sky, way further than I could see, and I felt very small and insignificant. Putting my hand on the trunk of one immense tree, I felt that this was more than just an inanimate hunk of wood. It was an enormous living thing. Looking straight up, I saw a raindrop falling from one of the branches a couple of hundred feet up. It fell, and fell and fell before hitting me straight in the eye.
— An h2g2 Researcher

Humboldt Redwoods Visitor Center

Any visitor to the park should go to the visitor centre. Not only are there interesting exhibitions about the forest, but the helpful staff will offer advice on how best to see the trees. They can suggest walking routes ranging from ten-minute strolls to full-day hikes.

The Founders Grove

There is a small nature trail marked out in this grove which takes 15 to 30 minutes to complete. Along the way, you'll encounter two very impressive trees — the Founders Tree, and the Dyerville Giant which fell in 1991 but is still lying undisturbed on the ground.

The Founders Tree is 346 feet tall, has a diameter of 12 feet and is reckoned to be 1,300 to 1,500 years old.

The Dyerville Giant was the tallest tree in the world until it fell in 1991. Standing at 362 feet, it was eight feet taller than St Paul's Cathedral in London. The trunk had a diameter of 17 feet, and the tree was estimated to be 2,000 years old. When the tree fell, it was not removed but left to rot away on the ground, a process which will take many years but will return nourishment to the soil so that future generations of redwoods can continue to live in the area.

Founders Grove is dedicated to the founders of the Save-the-Redwoods League.

The Big Trees Area

The area of the state park known as the 'Big Trees Area' contains a number of very large trees, including the Tall Tree (359 feet), the Giant Tree (363 feet tall and 17 feet in diameter) and the Flat-Iron Tree which fell in January 1995. The latter's trunk is still visible, with its unusual proportions of 7.5 feet in one direction and 17.5 feet in the other.

Redwood National and State Parks

This umbrella title covers a number of separate parks which stretch along the coast from the Oregon border for about 70 miles, down almost to McKinleyville. Within the group are Prairie Creek Redwoods State Park, Del Norte Coast Redwoods State Park, and Jedediah Smith Redwoods State Park. There is also some forest which is outside the state parks but included in the national park. Together, the parks contain 45% of all coastal redwoods in California. The park group has its headquarters at Crescent City, described by one h2g2 Researcher as 'the land of horizontal rain'.

There are rangers from both park systems at the park headquarters. You can ask any ranger about either the national or state parks, as they are knowledgeable about both (at least at the asking-over-the-counter level; more specific information may need to be referred). There is a nice gift shop to browse if there's a long line at the information counter.

Several excellent hiking trails are immediately accessible from the highway in the vicinity of Jedediah Smith State Park, at least one of which is wheelchair accessible. Prairie Creek State Park is home to Tall Trees Grove, which contains some of the tallest trees in the world. The park is home to a large herd of Roosevelt elk.

Klamath - Trees of Mystery

Also in northern California, in the same area as Redwood National Park and about 40 miles from the Oregon border, is the privately owned 'Trees of Mystery' park. Here you can see:

• Huge fibreglass models of the giant Paul Bunyan (49 feet tall) and his blue ox, Babe (35 feet). This folk hero strides through the tales of the original white settlers of the area². This particular model can wink, and is fitted with a jointed wrist and loudspeaker so that he greets all visitors individually.

This speaks volumes about American roadside attractions.
— An h2g2 Researcher

• A trail through the redwoods will bring you to the actual trees of mystery — redwoods which have grown completely naturally into many strange shapes, rather than the usual 'straight-up'. The Lightning Tree grows in a zig-zag shape. The Cathedral Tree is actually a group of trees growing in a tight circle around the spot where an older tree stood. This spot is often used for weddings and Easter religious ceremonies.

• The 'Skytrail', a cable-car ride³ high up in the canopy of the forest.

• Quite a large Native American Museum.

• And, of course, there's a gift shop where you can buy carved wooden bears etc, etc.

Drive-Through Trees

A coastal redwood can survive even if much of the base of the tree is removed. Forest fires occasionally leave a tree with a gaping hole in the base. The USA being the car-based country that it is, someone had the bright idea of hollowing out one of these and making the hole big enough to drive a car through. This became a fad and there are now a few 'drive-through trees'.

One such is the 'Chandelier Tree' at Leggett, in a private park called, predictably, 'Drive-Thru-Tree Park'. For a nominal fee⁴, you can experience the thrill of driving through the base of a tree. SUV owners please note, however, that your car may not fit through the gap.

The Chandelier Tree itself gets its name from the fact that it splits into numerous trunks about a hundred feet up, making it look a bit like a chandelier. It is claimed by the owners to be 2,400 years old, although this is denied by the people in the Humboldt Redwoods Visitor Center.

There are two other drive-through trees in northern California: the Shrine Drive-Thru Tree is on the Avenue of the Giants at Myers Flat; the Tour-Thru Tree is further north in Klamath, almost at the Oregon border.

The Petrified Forest

The Napa Valley is slightly too far from the ocean to be a home to coastal redwoods, but 3 million years ago conditions were different. Near Calistoga you can see the petrified remains of redwoods which were growing there at that time. These trees were knocked down and buried by a fall of ash from a nearby volcano (probably Mount St Helena⁵), and then by a quirk of nature were turned to stone. The process of petrification is a strange one. Water flows slowly through the structure of the wood, depositing silica (quartz) crystals in the cells and removing the biological matter at the same time. This gradually replaces the cells with stone copies of them, resulting in a lump of stone with an identical structure to the original tree, down to the cell level.

If you're in the Napa Valley, it's well worth your while making a trip to see these ancient giant trees.