Reasons Behind Leaves Color Changing in Fall

The fall season generates new and colorful leaves adorning the trees after the harsh winter.

Reasons Behind Leaves Color Changing in Fall
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Reasons Behind Leaves Color Changing in Fall


As a part of today’s trend, autumn has turned into a pumpkin spice season. But some people still love this season for its nature hikes and beautiful fall foliage.  

In terms of biology, autumn plays a great role in the transformation of plants. The season has shorter days with less sunlight. This means plants get less energy from the sun. On the other hand, the deciduous trees that lose leaves in the winter need to take preparation for the frozen season coming next.   

It is the physiological changes in the plants that influence leaves coloring before they fall off finally. So, why does this happen?

We all know that the main reason why the leaves are green is chlorophyll. Photosynthesis is the energy-generating process for the plants. In this process, chloroplasts that are full of chlorophyll works hard to absorb the sun’s light. After that, it triggers a chain reaction. For this reaction, a sugar naming glucose is produced. It works as a fuel for the plant.  

Another scientific term related to this photosynthesis is the reflection of the sun’s light. In this process, the green leaves reflect the green light in the environment. For this very reason, we see the leaves in green color. It is the chlorophyll that reflects the green light.  

So, you might be wondering why the color of the leaves changes in other forms rather than being green? Well, we have already mentioned that the autumn days are short. This shorter period does not allow the plants to do photosynthesis for long. In response to the shorter days and lower temperatures, they adapt a change sp that they can prepare themselves for the winter season. This change includes a breakdown of the chlorophylls.  

This breakdown causes a lack of chlorophyll in the leaves and they do not appear to be green like the previous stage. Not the chlorophylls are lessened. Rather, they are replaced with other pigments in the leaf. For instance, the pigment naming carotenes are responsible for making the leaves to look red or orange. While the xanthophylls make the leaves to look yellow.   

We can see a mixture of pigments in different trees. This mixture differs from one tree to another. That’s why the maple tree in front of you looks red. While driving on the road, you are in the middle of yellow because of the same reason. The oak trees’ leaves are brown because of the mix of many pigments. 

If you are curious enough to find what other pigments are available in the trees in your neighborhood, you can try the trick to remove chlorophyll from the leaves in your home. 

Some other factors affect the leaves’ color. You might have noticed the appearance of the leaves. Some of them look brilliant and some of them are nice only. It is the temperature and weather conditions that affect the looks of the leaves in autumn. 

Sunny days are trees’ best companion as the sun shines brightly. The more the sunshine is, the more time the trees get to produce glucose. The extra sugar then used by the trees to produce more pigments. In warm weather, the leaves look greener after a series of sunny days. If the days become frosty, the leaves start to look dull.  

The instance of the color effect due to micro-changes around the trees is also evident. You will see the difference in the color between low ground forests and high ground forests. The low ground forests face an up-down temperature day and night. So, color changes more quickly here than the high ground forests. This difference is also seen in the trees of the city and countryside. 

So far, we have learned why the color change occurs in the leaves. Now, let’s see why they fall off. The abscission layer is a special layer of cells in a leaf. This layer keeps the leaf stem attached to the branch.  

When the days start to get shorter, plants start to slow down circulation to the layer. At one level, the tree stops supplying food and water to the layer and at last, the leaf falls off.