Ever wondered where the orange in glorious autumn leaves comes from? The Forestry Commission have produced a nifty infographic that tell you just that... and a whole lot more about nature's most dramatically coloured season.
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.
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 www.forestry.gov.uk/autumn.