Why do leaves change colour?
Post categories: Autumnwatch,ÌýPhenology
| 11:33 UK time, Tuesday, 4 October 2011
Vibrant shades of red, gold and orange © Richard Becker/WTPL
Guest bloggers: Beverley Gormley and Kimberley Tew from the Woodland Trust.
Many trees are starting to take on their beautiful autumn colour. Where just a few weeks ago there were many shades of green, we're now starting to see vibrant shades of red, gold and orange as the season shifts.
Across the UK, band of have been logging their sightings so that we can watch autumn colour sweeping across the country. You can see this phenomenon for yourself on our .
The beauty of autumn © Ken Leslie/WTPL
You just can't escape the fact that nature is stunning at this time of year. From bright red and in the hedgerows to and the golds and reds of ; Mother Nature is in her evening gown and painting the woods red.
But why do leaves change colour so dramatically before falling from deciduous trees? Leaves contain chemical pigments, like chlorophyll, that makes leaves green and helps in the process of photosynthesis (which literally means 'putting together with light'). The leaves also contain the chemical carotene which has a yellow colouring.
Carotene is in the leaves all year, but is masked by the green of the chlorophyll. As autumn approaches and temperatures, especially those at night, begin to drop sharply, the chlorophyll breaks down and reveals the other pigments within the leaf (such as the carotene) that aren't affected by the cooler temperatures.
Lime leaf © Anna Bradley/WTPL
Autumn's display is more or less vibrant depending on the weather. To get the most vibrant autumn colours, you need a dry summer followed by dry, sunny autumn days with cold, but not freezing, nights. On the other hand cloudy and rainy autumn days lead to muted autumn colours.
You can go and enjoy nature's beautiful autumn display for yourself in your local woods. We've created a search for broadleaved woods which are likely to have some of the best autumn colours on VisitWoods. Simply enter your town or postcode in to our autumn wood finder to .
We're really interested to see what happens this autumn after such a record breaking spring and would like to invite you to join our band of nature recorders. The sightings you provide are used by scientists, the government, the media and even Autumnwatch. If you'd like to know which natural events are coming up next and what , we have a that shows what to expect and when.
What's the autumn colour like where you live? Do you have any favourite spots where autumn's at its finest? Let us know by posting a comment below or have at look at the , where you find the best autumn colours near you.
Comment number 1.
At 5th Oct 2011, littlejojo61 wrote:Visited Westonbirt this week and as well as admiring the glorious autumn scene I think I read that the change in colour can deter certain insect attacks? Did I imagine that or could there be something in it ?
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Comment number 2.
At 5th Oct 2011, tedbun wrote:Now, "proper" autumn begins ... excellent; another wondrous season in store! Hullo to presenters et al, "old" and "new" - and good luck (particularly given all this weather we've been having lately - and also now predicted around the UK ... which (mainly sadly) seems to have confounded much of the season's nature around here (on the Thames, on the very eastern edge of the City)). I'm very keen to discover this year's wild "winners" and "losers", so hope that your shows will provide lots of information on the causes and expected effects of all the changes (especially regarding the many "marker/benchmark" species) and the likely wider implications, future predictions etc. I'm also hoping to learn loads more from a whole host of different specialists - including the expert, excellent (and highly-entertaining) "geeks", naturally! Best regards to all, TB/EB.
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Comment number 3.
At 7th Oct 2011, timmalby wrote:30 years since my Biology A Level, and a bit sad I acknowledge, but isn't it because it is the method used to remove the bad chemicals (excretion etc) and helpfully, because as the sun is lower and weaker in the sky, the varying colours (of reds and browns) are more efficient at extracting the suns energy at this time of year than green? You see, there's always efficiency in Nature, that's why it is!!
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Comment number 4.
At 12th Oct 2011, Rsw15 wrote:I have a liquid Amber in it's first year. leaves are meant to be bright red but they are a boring dull yellow. why might this be?
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Comment number 5.
At 4th Nov 2011, John wrote:A tree lives as much below gound as above it. Any plant will condition the soil in which it's rooted to suit itself. It will change the PH and other conditions quite dramatically, until the soil suits it's particular needs. Trees are very good at this. On masse, they create a forest floor, quite different from open land. I'm willing to bet that the chemicals put into the leaves by trees are put there to create the right environment for it's root ball.
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