What autumn phenomena are observed in the life of shrubs?

Autumn changes in shrubs begin with a change in the color of the leaves. Green is replaced by yellow, red, orange or their shades. Everyone knows that chlorophyll gives green leaves. This is an unstable compound, but in the summer, due to the long daylight hours, chlorophyll has time to form again. In addition to chlorophyll, the leaves contain carotene, which turns the leaf orange, xanthophyll yellow, and anthocyanin red. What shade the leaf will become directly depends on the amount of pigments, and the brightness depends on the weather. If the day is clear, then the color of the leaf will be more intense than on a rainy day. After the leaves have turned yellow, leaf fall begins. This is a protective phenomenon against moisture evaporation. And also the fallen leaves protects the roots from freezing, and after rotting they will be fertilized.