What about the Colors?
The yellow in the trees is from a chemical called xanthophyll, which protects plant chloroplasts, organelles found in plant cells that hold genetics, carry pigment, store proteins or other functions. The xanthophyll absorbs the light in certain wavelengths, giving energy to boost the electrons. The name is from Greek xanthos, meaning “yellow" and phyllon for "leaf"
The orange hue comes from something we’re familiar with called carotene, which also makes pumpkins and sweet potatoes orange. Carotenes are antioxidants that protect the plant from free radicals, which are compounds that scientists believe may cause cancer in humans.
Reds and purples are the result of a chemical called anthocyanin—glycoside pigments in plant cells that produce blue to red coloring in flowers and plants. Anthocyanin is a naturally developing sunscreen. When broken down into molecules, anthocyanin includes a sugar. This affects the carbohydrates within a plant and the color comes out. Since anthocyanin color changes with pH, the acidity in the soil and plenty of sunlight are necessary for the leaf color, too.
Brown is from tannin, a substance found inherently in almost all plants, in all weather worldwide and particularly in roots, wood, bark and leaves. The brown color of trees such as the oak is made from wastes left in the leaves.