Weekend's Special: Coast Redwood, the World's Tallest Living

The coast redwood (Sequoia sempervirens) is one of the three sequoia species, together with the giant sequoia (Sequoiadendron giganteum) and the dawn redwood (Metasequoia glyptostroboides). The coast redwood grows in natural stands in a long, thin coastal area along the Pacific Ocean in the west and northwest of the US (mostly California). It is the tallest tree in the world.

With its relatively slender silhouette this tree can grow even 20 meters higher than the tallest giant sequoias, that are nevertheless the biggest trees in the world, when looking at the volume of the trunk. The tallest known living tree, named Hyperion, is 115.55 m or 379.1 feet (measured in 2006) tall! This gets close to 120 to 130 m, that, according to a 2004 biological study, is the maximum attainable height of a tree.

Foggy Coastal Forests of the Pacific

During the whole year it rains quite a lot in this thin coastal strip and it is quite foggy most of the time. This way the tree can absorb enough water and does not suffer that much from evaporation stress. Most of the tallest trees can be found in the wet river valleys on fertile, alluvial deposits, although unexpectedly a couple of recently discovered record breaking trees appeared to grow on the valley slopes. The coast redwood forests have an abundant undergrowth (amongst which there are a lot of ferns). However, the biggest biodiversity can be found tens of meters up: differents species of plants, lichens, salamanders, ... live high up in the sky between the complex branch systems of the redwoods. Prof. Steve Sillett, who studies these redwood canopies, compares them with "hanging gardens".

Description

On first sight, the needles of the coast redwood do not resemble those of the giant sequoia: they are bigger and flat, much like that of a yew. The crown is conical just like the one of the giant redwood, with an almost equally massive trunk with a reddish brown, soft bark. The egg shaped cones are smaller (2 to 3 cm). In contrast to most other conifers, the coast redwood starts to grow again after being cut. The maximum age is probably around 2500 years.

Because of the dramatic atmosphere, these forests have been used as scenery in movies: the scenes with the Ewoks in the Star Wars movies were shot in these woods, just as multiple parts of the Jurassic Park movies. For those last movies this choice is not very unlogic: during the Cretaceous, the top period for North American dinosaurs, these woods could be found all over the continent.

These trees (and especially young ones) are quite sensitive for winter frost and do not grow that well on the eastern side of the Rockies and in most parts of Europe. Biggest limiting factor is drought: it just isn't wet enough. In the wettest European parts, in England and Wales, planted redwoods do already reach 45 meters and more en seed themselves.

Tallest Tree in the World

The tallest tree in the world is a coast redwood (Sequoia sempervirens), named Hyperion after a person in Greek mythology. He is no less than 115.55 m (379.1 feet) tall! This enormous tree was discovered only in August 2006 in a remote part of the Redwood National Park, California by naturalists Chris Atkins and Michael Taylor. Their first preliminary measurements were done with professional laser measurement equipment based on goniometry.
In September 2006 the tree was remeasured by Steve Sillett. This was done in the most accurate way: he climbed to the top of the tree to drop a tape from there straight to the ground. This tape drop was filmed for National Geographic.

In July 2006 some other record tall trees were discovered: "Helios" (named after the Greek God of the sun), the world's tallest known tree as of June 2006 (114.09 m), "Icarus" (113.14 m), and "Daedalus" (110.76 m).

The discoveries of 2006 are remarkable: these trees appeared to grow on slopes and not in the center of the valleys where water is most abundant, and where all the previous contenders to the title "tallest living tree in the world" grow. This means that it's not unlikely that there are even taller, not as such discovered trees out there, simply because people weren't looking for them there. Now the forested slopes are being sought trough by tall tree hunters Chris Atkins and Michael Taylor. It's on a location like that that in August 2006 the current tallest (known as such) tree of 115.55 m was found.

In 2007 Chris Atkins and Michael Taylor had already scanned most of these new, unexpected locations. They think it's very unlikely a taller tree than Hyperion will be found, but you never know.

Hyperion has been quite lucky: only a few hundred feet from the base is the edge of a clearcut from the seventies. Clearcutting is a forestry practice in which all trees in an area are logged and the entire area is devastated. About two weeks before also Hyperion would have been attacked by the chain saws, this valley was added to the Redwood National Park during the Carter administration. Logging companies feared this would happen and worked 24/7 in the broad redwood valleys and kept logging old growth forests that were there long before men were ever entered these valleys.

In the seventies only an alarming 15% of the rich redwood forests remained, nowadays only 4% still exists and even today, as you read this, old growth Californian forests are being logged.

According to redwood standards, Hyperion is quite young and still growing vigorously. Sillett thinks the tree might be "only" 600 years old, which is about 20 years in human time.

Until July 2006 the tallest known Sequoia sempervirens was "The Stratosphere Giant". He is 112.83 m tall (measured in 2004, Steve Sillett) en was only discovered in August 2000 (by Chris Atkins) in Humboldt Redwoods State Park, California, where a lot of these giants grow. It is very difficult to appreciate the majestic height of these trees from a photo. The image on the left gives a little bit a sense of scale: on the right you can see a person hanging on a climbing rope.

Just as is the case with other giants, like the "The Federation Giant" (112 m), the exact location is kept secret by the park rangers to avoid a tourist stampede to the tree. This could unbalance the fragile ecosystem of the forest and could harm the tree directly: in the past things already went wrong for tall trees that became too popular.

In case you don't have a clue about how tall 115.55 m (379.1 feet) is: the height of Big Ben in London is 96.3 m (316 feet), that of the statue of Liberty is 46.5 + 46.9 m (151 + 154 feet), so both tall constructions are largely lower than these trees.

Note that although the tallest living tree in the world is a coast redwood, the biggest living tree on the planet is a specimen of a related species, the giant sequoia.

Tallest Redwood Ever?

It is absolutely uncertain if the tallest as such known Sequoia sempervirens is really the tallest Sequoia or the tallest Sequoia that grew in historical times. Indeed, it is very possible that in the logged parts of the original redwood forests (96%) there were taller specimens, who fell victim to the ever hungry chain saws.

Other species that can grow very tall are other conifers who also grow naturally on the northwestern coast of North America. Comes in second place: the Douglas-fir (Pseudotsuga menziesii) with 100.3 m (329 feet), followed by the Sitka spruce (Picea sitchensis), of which the tallest known specimen is 96,7 m (317,3 feet) tall. Just as the wood of coast redwoods, the wood of these trees is of excellent quality, so the once vast forests of these trees are almost completely gone. Without any doubt there were taller specimens in there. For example, in 1900 a Douglas-fir of 125.5 m (411.7 feet) was logged.

Tallest Tree Ever Measured

The tallest tree ever measured was no Sequoia sempervirens, but a type of eucalypt (Eucalyptus), an Australian deciduous tree (images).
In 1872 forester William Ferguson spotted an extremely tall mountain ash (Eucalyptus regnans) near the Watts River, Victoria, Australia. Purportedly he was 132.6 m (435 feet) tall. In that time, multiple specimens of 140 m tall were reported in Tasmania.

We cannot check these measurements anymore: all these trees have been logged... Mountain ash was and is an important construction material in Australia.

Some reserve about these old measurements should be kept. The tallest mountain ash of which the heigth was measured with some certainty was 114.3 m tall and was also logged (1884).

Even nowadays the deforestation in mainland Australia and Tasmania is continuing. The relationship between environmental organizations and the state company Tasmania Forestry are tense, especially since they burned the biggest Australian tree "El Grande", although it was an accident according to Tasmania Forestry.

The tallest living eucalypts can be found in Tasmania. The tallest one, named "Icarus Dream", is now 97 m (318.2 feet) tall and is the tallest deciduous tree on earth.