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Colour me happy – the chemistry of autumn colours

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Chemistry of autumn colours

In a recent survey carried out by Forestry Commission England a staggering 96% of people said that beautiful autumn colours improve their mood, but why do the leaves change colour? What makes a maple leaf turn fiery red, a beech become golden or an ironwood transform through a rainbow of colours to deep plum purple?

To help you understand the science behind the forest’s most vibrant season, Forestry Commission England has put together a simple colour guide:

During the spring and summer months, leaves are filled with green chlorophyll which helps trees to harness the sunshine and turn it into sugars (plant food).

To survive the winter, most trees will shut down to store their sugars. A cork-like membrane develops between the branch and the leaf stem, depriving the leaves of nutrients and breaking down the chlorophyll.

The yellows of autumn leaves come from xanthophyll pigments and can be seen throughout autumn in a variety of trees including birches, beeches, ashes and field maples. Egg yolks are yellow because of the xanthophyll in plant products, eaten by the hens.

Orange comes from beta carotene – one of the most common compounds in plants. One of the best trees to see carotene in action during autumn is sweet chestnut. Carotene, as its name suggests, is also the chemical responsible for giving carrots their bright orange colour.

The red colour is unlike other leaf colours as it hasn’t always existed in the leaf. The colour is caused by anthrocyanin pigments which are formed by a reaction between sugars and certain proteins in cell sap.

If the sap is quite acidic, the pigments impart a bright red colour. If the sap is less acidic, then the resulting colour is purple. Japanese maples produce plenty of anthrocyanins and have very bright red leaves.

Andrew Smith, the Forestry Commission’s Director at Westonbirt Arboretum explains:

“Different chemicals in leaves control the colours we see. During summer the leaves are packed with green chlorophyll, which harnesses energy from sunlight to combine water and CO2 to create sugars (plant food).

“However, once the tree shuts down as it prepares for winter, the chlorophyll breaks down and other coloured chemicals take over. Carotene, anthocyanins and tannins give the instantly recognisable colours of autumn, making leaves appear yellow, red, and gold.”

With a number of fantastic forest sites displaying the sensory delights of autumn, Forestry Commission England has named its top ten walks to boost your mood before the winter months.

From the lovely autumn colours which are set against the stunning lake at Bedgebury Pinetum to the amazing views from the new Tree-Top walk way at Westonbirt Arboretum, we have something for everyone. Our top spots are:

1. Forest of Dean, Symonds Yat
2. Grizedale, Carron Crag trail
3. Westonbirt, Silk Wood
4. Delamere, Blackmere Trail
5. Bedgebury, Seasonal Trail
6. Hamsterley, Bedburn Valley Trail
7. Salcey, The Church Path Trail
8. Wyre, Giants Trail
9. Alice Holt, Habitat Trail
10.  New Forest, Tall Trees Trail

For autumn walks and further information about how to colour yourself happy this autumn visit

Notes to editors
1. Andrew Smith is the new director of Westonbirt, the National Arboretum. He has worked for the Forestry Commission for 26 years he trained in Forestry at Bangor University and has held a number of senior management roles with the Forestry Commission in Yorkshire and at National Office.

2. The Forestry Commission is the government department responsible in England for protecting, expanding and promoting the sustainable management of woods and forests and increasing their value to society and the environment.

England's Woods and Forests are cared for by Forest Enterprise     England, an agency of the Forestry Commission.
3. Survey results are from recently online survey that was conducted by Forestry Commission England. It was completed by 1686 people.
4. The Forestry Commission Discovery Pass gives free parking for the year for your local Forestry Commission Woodland, plus a range of other great discounts. Further information can be found at

5. Forestry Commission England’s top 10 #autumnleafwatch walks:
• Forest of Dean, Gloucestershire: Symonds Yat
• Grizedale Forest: Carron Crag
• Westonbirt Arboretum, Gloucestershire: Maple loop in Silk Wood
• New Forest, Hampshire: Tall Trees trail
• Alice Holt, Surrey: Arboretum tree trail
• Delamere Forest, Cheshire: Blakemere trail
• Bedgebury Pinetum, Kent: Seasonal trail
• Lynford Arboretum, Norfolk: Seasonal trail
• Wyre Forest, Shropshire: The Giants Trail
• Hamsterly Forest, Durham: Bedburn Valley trail
Media contact: Rebecca Ulewicz, Media Relations Officer: or 0300 0674107