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Giant sequoias thriving in UK and could grow as tall as in California

Giant sequoia trees, first imported to the UK 160 years ago, are flourishing despite the dramatically different climate to their native California, a new study has found.

The huge trees, which are declining in numbers in California due to increasing heat, are adapting well to the British climate and growing taller, according to a study conducted by UCL researchers.

“The growth here in the UK seems to be suited to our wetter climate, so there’s far less chance of water stress here than in the Sierras in California,” the study’s co-lead author and a professor of geography, Mat Disney, told The Independent.

Giant sequoias are one of Earth’s largest and longest-living trees. Their large trunks and extensive foliage mean they can potentially absorb an average of 85kg of carbon per year in their 3,000-year lifespan, more than many other tree species.

Researchers mapped nearly 5,000 individual trees in the UK and found that these giants grow well in the country, providing an opportunity for more carbon sequestration.

This is the first time the trees’ growth rate and resilience in the UK have been analysed, according to the study, which was published in the journal, Royal Society Open Science, on Tuesday.

The study used terrestrial laser scanners to create 3D models of the trees, accurately measuring their heights and volumes without causing harm.

A 3D laser scan of a Giant Sequoia (Mathilda Digby)
A 3D laser scan of a Giant Sequoia (Mathilda Digby)

“We found that UK redwoods are well adapted to the UK and able to capture a large amount of carbon dioxide,” said Ross Holland, a co-author of the study. “We hope that these findings can help guide decisions on future tree planting and management.”

Although the tallest UK sequoias are about 180ft smaller than their American counterparts, which can grow up to 300ft, the researchers said that it shows how well they are adapting.

“They are pretty big by UK standards,” Dr Disney said. “But not by Californian standards. But they are still very, very young for giant sequoia, and so if they survive the next couple of hundred years, they will become much taller.”

Dr Disney suggested that the trees could theoretically become as tall as those in the US – but that the UK ones will face serious hurdles in doing so, because they don’t have the same strength in numbers as their Californian cousins.

“It’s unlikely they will reach the heights of the California giants though because the taller they get, the more they tend to stick out in the landscape compared to their surroundings, and hence the more prone they are to lightning strikes and wind damage,” he said.

Despite their endangered status in California, where less than 80,000 giant sequoias remain, the UK is home to an estimated half a million of the trees.

Their numbers are growing partly due to their public appeal and the environmental benefits as people plant these giants to offset their carbon emissions.

“Currently, these trees are probably more important for their aesthetic and historical interest than they are for solving the climate crisis,” Dr Disney said.

“But as more are planted we need to know how they will grow.”

The researchers stressed that while reducing carbon emissions is crucial, dense forests made up of trees like Giant sequoias can also play a role in fighting off the climate crisis.