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WONDERS OF EARTH

How honey is made?

Why leaves change color in autumn?

The problem with keeping leaves in the winter is that when temperatures get low, the cells in the leaves can freeze, and this way kill the whole tree. So to conquer vaster chunks of land with harsh conditions, trees have developed this tactic to survive the otherwise crucial winters.

You have probably seen the phenomenon in which leaves change color in autumn and then fall. Some people say that leaves change color because they lose their chlorophyll, but this doesn’t explain much. So why do some trees let their leaves fall in the autumn?

When trees lose their leaves, they throw away the product of so much work done during the whole year. And if simply dropped, the leaves would take the precious elements stored inside with them. Which not only sounds impractical, but it really is. So trees don’t just scrap their leaves but instead recycle them. This way, they can return their precious elements stored inside the leaves and also protect themselves to survive the winter.

But recycling leaves is not an easy task. First, trees need to extract every valuable resource inside them before they can let them go. This also creates a problem on its own because when the needed elements for photosynthesis are taken away, the process cannot continue, but the leaves that still contain chlorophyll that keeps producing energy. This can become a serious problem because when the leaves keep extracting energy, they can start energizing oxygen atoms which, can become dangerous and deal some serious damage.

By changing the color of their leaves, trees have solved the two problems at once. Prevented damage from energized oxygen atoms and kept themselves safe during the winter.

The coloring of the leaves is because trees break down their chlorophyll into less dangerous molecules that are mostly colorless but sometimes yellow and orange. Some trees get extra safe by producing molecules to shade the chlorophyll while it is being broken down, and these molecules are typically pink or red. This is why some trees shade their leaves with red colors that sometimes can be insanely bright.

By being adaptive, and maybe the best recyclists in the world, trees have managed to conquer most of the planet's surface and dominate it until humans arrived.