Around November, leaf fall starts. There are piles of leaves everywhere, on the roadside, on the roofs, in the society premises; just about everywhere.

Did you notice, none of the leaves are green. They used to be green on the tree. But then they turned yellow or brown and then they fell.

Why so?

Why do they change color?

First, let’s discuss why leaves have green color, in the first place.

In simple words, trees prepare food by the process called “Photosynthesis”.

Here is the exact definition, thanks to Wikipedia, Photosynthesis is a process used by plants and other organisms to convert light energy into chemical energy that can later be released to fuel the organisms’ activities

Photosynthesis is derived from the Greek word, phos – Light and synthesis – “Putting together”.

For photosynthesis, they require, water, sunlight and carbon dioxide, and chlorophyll, that is present in the leaves.

Because of chlorophyll, leaves have green color.

In nature, there is no waste. All resources are used and reused.

Why to waste chlorophyll in the leaf that is about to fall?

Hence Chlorophyll is absorbed by the tree.

Leaves have green color due to presence of chlorophyll, once it withdraws, green color goes away.

Then whatever is next dominant pigment in the leaf, leaf will have that color.

It could be yellow / red or brown.