There are more Giant Redwood trees in the U.K. than there are in their native habitat in California. How’s that for an incredible statement, which happens to be true.
Giant redwoods – the world’s tallest trees – are flourishing in the U.K., a study has found. The trees, which were first brought to the U.K. about 160 years ago, are growing at a similar rate to those found in their native range in California.
I found this story slightly amazing in that these trees have been in the U.K. for 160 years and I, for one, have never heard that they grew in my native land at all.
Scientists believe the U.K. trees are now outnumbering the ones in the mountains of Sierra Nevada. However, they aren’t yet as tall. In California the biggest reach 90m high, but in the U.K. the tallest is 54.87m. But that’s because the introduced trees are still very young. Giant redwoods can live for more than 2,000 years, so there’s still plenty of time for the U.K.’s trees to catch up.
It’s estimated there are half a million GIANT redwood trees in the U.K. – this includes the giant redwoods studied (Sequoiadendron giganteum – also commonly called giant sequoias) as well as coastal redwoods and dawn redwoods, both of which were introduced at later dates. But the scientists in the study say they think most of the U.K. trees are giant redwoods. By comparison there are about 80,000 mature giant redwood trees in their native range in the forests of California.
“Half a million trees is quite a lot to go under the radar until now, but it’s when you start looking for them in the landscape, and compiling these datasets, that you realise how many there are,” said Dr Phil Wilkes, one of the authors of the study, from Kew’s botanic garden at Wakehurst in Sussex.
Giant redwood trees were first brought to the U.K. by the Victorians. They were the ultimate botanical status symbol, typically planted in the grand estates of the wealthy. Today, some form sweeping avenues while others stand in ones or twos. But they’re easy to spot: their dense, cone-shaped crowns stand proud of everything around them.
To assess how these towering giants are adapting to their U.K. home, scientists selected a sample of nearly 5,000 trees to study at Wakehurst, Benmore Botanic Garden in Argyllshire, Scotland and Havering Country Park in Essex. They used laser scanners to measure the heights and volumes of some of the trees – it’s also a way to weigh the trees without cutting them down.
The researchers found that the trees were growing about as fast as the giant redwoods in their native home in the mountains of Sierra Nevada. The U.K. climate seems to suit them, says Dr Wilkes.
“Where they grow in California, it’s cooler and moister than you would typically envisage California to be,” he explained. “And we have a reasonably similar climate here – it’s very wet and they need the moisture to grow.”
The scientists also looked at how much carbon dioxide the trees were absorbing – trees soak up and store the greenhouse gas and planting more trees can play a role in helping to tackle climate change.
The researchers found that because of their sheer size, giant redwoods can lock up large amounts of carbon dioxide in their wood – although not as much as their U.S. counterparts.
The trees at Wakehurst, which are about 45m tall, have about 10 to 15 tonnes of carbon stored in them, Dr Wilkes explained. “But compare this to the largest tree in California, which has about 250 tonnes of carbon stored in it, and they’re quite small. But you know, these could get as big.”
The scientists involved in the research are quick to point out that planting forests of giant redwoods would not be enough to significantly reduce the amount of carbon dioxide in the atmosphere. But these majestic giants can play a part in a mixed forest plantation with a variety of other trees, both native and imported.
In California, the natural wonders are under threat from climate change – they’re not faring well with hotter and drier weather and more intense wildfires. So, could the U.K. become their new home?
In an avenue of trees originally planted as a grand entrance to a now demolished mansion in Havering Country Park, Prof Mat Disney, from University College London, says he thinks it’s more than possible. “In terms of climate, it’s probably the case that they’re going to have a less pressured existence here than they do in California,” he said. Although he pointed out that conditions are also changing in the U.K.
Giant redwoods are being planted as saplings all over the country, often by local authorities in public parks or recreation grounds.
Professor Disney says they have a long life ahead of them – and they won’t stay small for long.
“They’re very fast growing, and they grow large. Once they reach about 60m, they will be the tallest trees in Britain, and then they will keep on growing,” he said.
However, while the trees are doing well in the U.K., there’s little chance of them taking over our native forests any time soon – they’re not reproducing there naturally, as they need very specific conditions to take seed. (I have to do more research to find out why and what those very specific conditions are.)
I am still amazed at this story and wanted to pass it on.
