Our friends at Forestry Commission England carried out a survey on how we feel about autumn, and a staggering 96% of people said that beautiful autumn colours improve their mood.
These stunning colours draw in the eye and make us happy, but why do leaves change colour in the autumn? What science is going on behind the scenes?
To understand this, have a quick look at the phases which a tree goes through.
[Hint: you can follow these phases on this interactive map, which tracks the changing seasons]
Phase 1: The growing season begins…
Like any other living thing, trees need to take in energy. Unlike any other living thing, trees do this through solar power. Pretty impressive huh!
During spring and summer, the tree bursts into life and uses the sun’s rays to grow new shoots. Once the buds are set and the leaves are fully expanded, the tree fills its leaves with a green-coloured chemical called chlorophyll. This chemical is what allows trees to harness the sunshine and turn it into sugars (tree food). Yum!
The tree is constantly topping-up the chlorophyll during this growing phase, as the chemical is continually being broken down to produce food when it’s exposed to light.
Phase 2: Power down
When the days grow shorter, the light and heat levels drop, so the trees’ ‘solar panels’ power down. The tree creates a block between the branch and the leaf stem, depriving the leaves of nutrients and preventing chlorophyll from being topped-up.
Phase 3: Colour breakouts!
In autumn, the green chlorophyll begins to break down, uncovering other brightly coloured pigments hidden within the leaf.
On some trees you’ll see the rich oranges (carotenoids) or yellows begin to break through, (anthophylls). On others you’ll see a beautiful deep red or purple. These colours come from anthocyanins, which the trees make from the sugars trapped in the leaves.
Next time you look up at a golden autumn tree, you can smile knowing that a tree produces its colour as part of its annual growth cycle.
We’re in for a treat this autumn!
Luckily for us we’re in for a great season of colour this year, and here’s why…
Andrew Smith, the Forestry Commission’s director at Westonbirt explains that because of “the abundance of rain we experienced in spring, coupled with above average sunshine, has meant a great growing season for trees as it allows them to build up plenty of sugars in their leaves.”
Andrew goes on to explain that, thanks to a warm autumn (one of the hottest Septembers in over 100 years in fact), our forests will stay colourful for even longer this year!
All the more reason to head to one of the Forestry Commission’s top 10 autumn walks! They’ve hand picked the finest forest walks from around England for you to experience the stunning colours of autumn. It’s all part of their #ColourMeHappy campaign, which is encouraging people to get outdoors to make the most of this beautiful season.