Scientists found out why tree turn red during Autumn. Emily Habinck from the University of North Carolina, Charlotte studied the tree in flood plains and in adjacent upland area. The soil in the upland area was low in nutrients, and the leaves there were bright red. In the floodplain, where the soil was full of goodness and the autumn leaves remained yellow.

"the redder a leaf is, the more nutrients it is going to recycle," she says

Color changes in leaves are not fully understood, at least not when it comes to the redder hues.

As autumn approaches, trees begin to break down the green chlorophyll in their leaves and redistribute the nutrients contained there to their trunk and roots. The yellow colour is the result from the loss of chlorophyll. It unmasks the yellow carotinoids that were there all along. But red coloration comes from a pigment called anthocyanin, which has to be made afresh as autumn takes hold.

Why trees bother spending energy doing this has been widely debated. Some say these pigments act as antioxidants, which help a tree combat harsh conditions. Others it helps to attract birds that can then disperse fruits. Or it might increase leaf temperature, helping to protect from the cold.

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