Category: Primary 5

At Club Wild we have been looking at why leaves change colour and fall off their trees in the Autumn. We learned that the word for this is Senescence and this occurs in mid to late Autumn as different deciduous trees change from green leaf to a variety of colours.

It is funny to think that most of the spectacular colours of Autumn have actually been in the leaves all summer, covered up by the dominant green chlorophyll. As the weather cools and shorter days settle in, the chlorophyll starts to break down, revealing new and varied colour pigments. the brightest colours are seen when late summer is dry and autumn has bright sunny days and cool nights.

We went out to see if we could find and collect leaves with the different pigments. Some trees still had the green chlorophyll​. Chlorophyll is responsible for helping trees and plants turn sunlight into food.  The red, anthocyanin that we found in some leaves is produced as the chlorophyll is broken down unlike other pigments which always exist in the leaf. The yellow, xanthophyll can be seen throughout the Autumn on trees including birches, elms and oaks. The orange, carotene can be found beautifully on sugar maples. As the name implies, carotenes are also the chemical responsible for giving carrots their colouring.