Redwood trees holiday in the UK and now it looks like they will be staying for good

Researchers from the University College London and the Royal Botanic Gardens, Kew, reveal that giant redwoods are thriving in the UK, using sophisticated analyses to determine the growth rate of a selection of trees and their ability to sequester carbon.

A taste for grandeur

Redwood trees (including giant redwoods, Sequoiadendron giganteum, and coastal redwoods, Sequoia sempervirens) have a distinct red/iron-colored bark that is fire-resistant, and impervious to fungi and insects. If you have never seen one of these beautiful trees, you may have wandered down to the Natural History Museum in South Kensington, London, and gazed up in awe at the slice of a giant redwood at the museum's topmost floor.

Redwoods are thriving in the UK! A new study with @ucl found giant sequoias are growing at rates close to their native ranges and capturing large amounts of carbon. The team mapped our redwoods in 3D with LiDAR scanners to measure their heights and volumes! #BritishScienceWeek pic.twitter.com/zc8PbzfXCb

— Wakehurst (@wakehurst_kew) March 15, 2024

According to Forestry England, redwoods came to the UK in the 1800s via the Victorians, who coveted their grandeur and wished to emphasize wealth and status when planted in their gardens. Sadly, the overexploitation of redwoods for their timber during this time has led to a decline in their population within the Sierra Nevada, California.

Over half a million giant sequoias, along with their close relatives the coastal redwoods, reside within the UK compared to California’s 80,000 mature giant redwoods. The coastal redwoods in California favor moist, damp environments, and with the UK having a temperate climate, it is understandable why redwood species have become so prolific.

While California may not have as many redwoods, it certainly has the tallest at 90 meters high compared to the tallest height of 54.87 meters recorded at Benmore in the UK. The redwoods in the UK are considered youngsters and are still catching up.

Redwood growth and carbon storage capability

The study utilized 97 tree samples from sites including Benmore Botanic Garden in Argyllshire, Scotland, Wakehurst, and Havering Country Park in Essex.

The researchers used laser scanners to record tree height, volume, and weight, discovering that trees at Benmore were taller than those at the Wakehurst and Havering sites. Despite having taller and older trees, the trees at Benmore grew much slower than those at Wakehurst.

The researchers show that giant redwoods growing in the UK can capture and store carbon at a rate of 85 kg yr−1, varying with weather changes, management, and tree age. Not surprisingly, the Californian redwoods can store far more than the young trees inhabiting the UK, as much as 250 tonnes of carbon. The trees at Wakehurst—around 45cm in height—store 10 to 15 tonnes of carbon. The UK trees may well grow as big as the Californian trees, meaning more carbon can be stored as biomass.

However, the scientists of the present study say that the carbon stored by the UK trees is not sufficient to dramatically reduce the carbon in the atmosphere. However, the UK redwoods can add some diversity to plantation areas and their fire-resistant properties may prove beneficial as temperatures continue to rise in light of global climate change.