In late autumn, the weather turns cool, and the grass gradually turns yellow and withers, showing the characteristics of life.

It is aging, and the reason for falling leaves in autumn is that the temperature drops and metabolism is affected.

Leaves contain green chlorophyll, and trees use chlorophyll to capture light energy, and with the help of other substances in leaves, they are stored in the form of chemicals such as sugar. Besides chlorophyll, many leaves also contain other pigments, such as yellow, orange and red.

When autumn comes, the days get shorter and the nights get longer, which makes the trees begin to shed their leaves. Before the leaves fall, they no longer produce a lot of chlorophyll, the pigments will decompose, and the leaves will show yellow, red and other colors.

After autumn comes, trees feel the climate change from autumn, which makes a lot of phytochrome cover the green chlorophyll, and people naturally see the leaves turn red or yellow. In autumn, deciduous trees stop growing and only need a small amount of nutrients to survive. Before the leaves fall, the trunk decomposes chlorophyll, and the substances produced by decomposition are transported from the leaves to the treetops as nutrients for winter.