Wales is such a great place to see Autumn colour. Red and Gold, Orange and Yellow, colour the trees of our woodlands in September, October and November.
In these shorter days of Autumn and as the days turn colder, the green pigment in the leaf called chlorophyll breaks down, leaving leaves to turn yellow.
Chlorophyl is the amazing compound that turns sunlight into sugars to feed the plant. Less chlorophyll is needed when sunlight is less in the shorter days leading to Winter.
As the green disappears, the residual colours are beautifully revealed. The yellows are compounds called flavanols. Carotenoids show as orange, and anthocyanines show as red or purple.
Interestingly if it is dry and not freezing, more of this anthocyanin is made and the leaves become redder. The drier the weather the redder the leaves. Different species of trees have differing levels of these amazing compounds, producing this spectacularly colourful effect.
Abscisic acid seals the base of the leaves, any compounds remaining in the leaves now stay there, and the leaf falls to the ground, and then there's all the joy of walking through Autumn leaves. Love Wales :)

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