Seasonal Changes .
In the warmer seasons (summer and spring), leaves produce chlorophyll which is what makes the leaves green. Chlorophyll also helps plants absorb sunlight, which keeps them alive. Under the leaves are pigments (red, yellow, orange, and purple). They are always there, just hidden. Trees start to break down the green in their leaves when fall comes around. They keep the nutrients in their leaves for spring. When leaves lose their chlorophyll (green color) that's when the pretty autumn colors start to show. When leaves turn brown that means all the pigment is gone. Red leaves are extremely special because they're mixed with red pigment and chlorophyll. They are especially present in places where its sunny in the day and cold at night.