Why Leaves Change Color Throughout spring and summer, leaves serve as factories manufacturing the food necessary for a tree's growth. The food-making process takes place inside leaf cells, in tiny structures called chloroplasts. The chloroplasts contain chlorophyll that gives the leaf its green color. The chlorophyll absorbs energy from sunlight and uses it to transform carbon dioxide and water to carbohydrates, such as sugars and starches. Chlorophyll is unstable and must continually be replaced.
Light is essential for chlorophyll manufacture.
The tree's nutrition also affects the amount of chlorophyll in the leaf. If nitrogen, iron, magnesium or some other element is scarce, the rate of chlorophyll formation will decline. Restoring these nutrients will increase chlorophyll production. In the fall Missouri is awash with color from our wide variety of deciduous trees. Darker concentrations of color on tis map indicate where the most fall color can be found.