Giant sequoias, emblematic trees of Californian natural parks and major carbon absorbers, are now much more numerous in the United Kingdom – where they have adapted well – than in their native land, reveals a study published Wednesday.
There are around 500,000 giant sequoias in the United Kingdom, compared to less than 80,000 still present in the natural state in California, according to this study led by the British university UCL and published in the journal Royal Society Open Science, which was interested in the carbon sequestration capacities of these unusual trees.
The giant sequoia forests in California, composed of trees ranging in height from 50 to more than 80 meters with a diameter of 6 to 8 meters, are among the densest in carbon in the world, notably due to the age of the trees that compose them, which can reach 3000 years.
“We found that British giant redwoods are well adapted to the UK and are able to capture a large amount of carbon dioxide (CO2)” as well, says Ross Holland, lead author of the study.
The giant sequoia was introduced to the United Kingdom in the mid-19th century.e century, and “quickly became a symbol of wealth” in the Victorian era, planted at the entrance to large properties, along major thoroughfares and in parks, researchers recall.
Today, in the context of the climate crisis, it is its CO absorption potential2 which interests scientists, who have studied the development and quantities of carbon sequestered in around a hundred British specimens, planted in various environmental conditions (soil, humidity, climate, etc.).
In two locations studied — a botanical garden in Sussex (southeast England) and another located northwest of Glasgow in Scotland — redwoods grew at the same rate as their American counterparts and developed capacities roughly similar carbon sequestration. Or around 85 kilograms of carbon absorbed per year.
On the other hand, those which were planted in a park around London, benefiting in particular from less annual rainfall, grow more slowly and produce less biomass (leaves, trunk, branches, etc.), capable of absorbing CO2.
With these results, the researchers hope to be able to make recommendations on the most suitable places to plant these redwoods in the future, and how best to maintain them.