They take carbon dioxide from the air. They turn water and carbon dioxide into food using sunlight and chlorophyll. Chlorophyll is green. It gives leaves their green color. Winter days are short and dry.
Many plants stop making food in the fall.
The chlorophyll goes away. Then we can see orange and yellow colors. These colors were in the leaves all summer, but the green covered them up. Some leaves turn red. This color is made in the fall, from food trapped in the leaves.