A GIANT redwood deep in a remote northern Californian forest has been declared the tallest tree in the world.

Confirmation of the new record-breaker came only after a tree-climbing scientist reached its top to confirm a height of nearly 380ft (114m) — a foot taller than previously thought.

Hyperion, which stands 379.1ft tall, is nearly nine feet taller than the previous record holder, Stratosphere Giant. Two other ancient redwoods discovered nearby were also higher than the previous best, knocking the old record-holder into fourth place.

Experts say that the chances of finding a taller redwood are extremely remote, meaning that Hyperion, at between 700 and 800 years old, may be in the record books to stay as the tallest tree — and living organism — on Earth.

Two amateur naturalists discovered the three giants deep inside Redwood National Park this summer after inspecting 95 per cent of the trees in the forest.

Researchers took laser measurements that suggested that all three — Hyperion, Helios and Icarus — were standing taller than the former record holder.

Scientists had to wait for confirmation until the end of the nesting season of the endangered marble murrelet, which makes its home among the redwood’s branches.

Professor Steve Sillett, the world’s leading expert on the ecology of ancient forest canopies, clambered to the top of Hyperion and dropped a measuring tape to the ground.

Professor Sillett’s method has made him a hero in scientific circles and has led to several awards. Before he began scaling the redwoods in the mid-1990s, no scientist had ever reached the canopy before, and little was known about their ecology.

Redwoods such as Stratosphere were regarded as insurmountable, with their first branches beginning at a height equivalent to 25 storeys above the ground.

To climb the giants, Professor Sillett uses a powerful crossbow to shoot a bolt, with a trailing line attached over a branch 250ft up its trunk. The line is then fixed to a rope, pulled over the massive branch, and then anchored to a nearby tree before he climbs the rope, using the trunk for footholds.

At the top of Hyperion, Professor Sillett discovered that damage by woodpeckers had robbed the tree of almost a foot in height.

The tallest tree ever reliably recorded was a Douglas fir in Lynn Valley, British Columbia, Canada, which was measured in the late 19th century at 414ft. It is no longer standing.

Scientists have yet to come up with an absolute limit on how high a tree may be able to grow but believe the Lynn Valley fir must be close. They also doubt whether any tree taller than Hyperion will be found — even though it is 25ft shorter than the fir in Canada.

Four decades ago there were thousands of trees comparable in size to Hyperion, but they were logged, along with 90 per cent of the ancient redwood forests in California. Hyperion was saved by the expansion of Redwood National Park in 1978.

Anyone wishing to visit the new giant will be disappointed. Officials have refused to disclose its exact location for fear that it will be swamped by visitors and thrill-seeking tree climbers looking to replicate Professor Sillett’s daring ascent.

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