Autumn is known for its stunning display of orange and red hues, and this year the leaves could be more vibrant than ever.
Sunnier summers have led to trees producing more sugar in their leaves, which will lead to more vivid and eye-catching colours, according to experts at Forestry England. The picturesque autumn leaves can be spotted from mid-September to November in some parts of the UK.
As the days gradually get darker, the lack of sunlight reduces a plant’s production of chlorophyll – the chemical responsible for giving leaves a green pigment – which allows the beautiful yellow and orange shades, previously masked by the chlorophyll, to show through.
Some trees will also turn a vibrant red – the result of anthocyanin production, which is greater in years such as this one, when hot summers have increased the concentration of sugar in tree sap. This triggers the tree to release anthocyanins as it tries to salvage the last of the energy from its leaves in preparation for winter.
The Met Office reported that this summer was the hottest on record due to the climate crisis. While stark changes in weather pose a number of challenges, they can also cause an explosion of brighter colours during the autumn.
As Forestry England said: “If we continue to experience warm days and cool, dry nights in September, we could see one of the most flamboyant autumn displays in recent years.”
Andrew Smith, director of Forestry England’s Westonbirt, the National Arboretum, said: “We’ve had a very warm and sunny summer, and that helps trees build up the sugars in their leaves that create those amazing autumn colours.”
He added: “The cooler nights and shorter days on the way will trigger the change, and we’re expecting a really beautiful display this year.
“Autumn is a fantastic time to get outside and reconnect with nature. The nation’s forests are already starting to change, and with such promising conditions, we’re expecting a colourful show from September right through to November.”
But Kevin Martin, head of tree collections at Kew Gardens, told the BBC: “We may not see the spectacular display when all trees change colour at once, as some trees have already changed and shed their leaves.”
In response to the stress of drought, some trees, such as the horse chestnut, have already turned brown and dropped in what experts call a “false autumn”. However, some trees at Kew Gardens have started to regrow temporarily in response to recent rainfall, in time for the real autumn season changes to come.
