why do leaves change colour in the autumn?

Categories Curiously Simple


My favourite time of the year is here again. Autumn has come back to say hello and remind us of her stunning colours, crisp air, dark mornings, and fresh smells. Her presence is well received after a dreary, chilly summer.

As I took a 15 minute jog this morning around our local park, I soaked in the changing colours of the trees. Reds, oranges, browns, and yellows.

Why do the leaves change colour? I decided to look it up. And quite frankly, I most appreciated the websites that were aimed for children. Because I am no scientist and other explanations went way far over my head.

My basic understanding is that during the spring and summer, leaves are the food makers for the plants. This food making process is called photosynthesis – turning light energy from the sun into chemical energy for the plant. Photosynthesis happens in the leaves, in the chloroplasts (food centers) using a a chemical called chlorophyll (a green pigment). So lots of food making happens in the summer as chlorophyll absorbs the plentiful sunlight and begins to transform it into food for the plant.

Lots of chlorophyll = lots of green colour in leaves.

But autumn and winter don’t see the sun as much. In Wales, the sun won’t come up till 8:30 in the winter and goes by 4:30 in the afternoon. Stupidly short days.

Without enough sun being caught, photosynthesis ceases to happen and the plant begins to use the energy previously stored. And as photosynthesis stops, chlorophyll disappears from the leaves. SO LEAVES LOSE THEIR GREEN COLOUR. And as the green pigment goes, the other colours emerge from the background. Hence, we then see the reds, oranges, browns, and and yellows.

And with the change of season comes the sweet reminder that life has seasons as well. Seasons of sweetness. Seasons of bitterness. Seasons of joy. Seasons of mourning. Seasons of community. Seasons of loneliness. Seasons of health. Seasons of sickness.

And each season comes to an end. But a new season is about to begin. And that sweet reminder brings me a glimmer of hope. Reminders of truth woven through creation and seasons. Autumn is here. Summer is over. Winter is to come. And Spring isn’t far away.

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