The Colors of Autumn

by Christy Rybka                                                            

Why do leaves change color in the fall?

Chlorophyll is the pigment that causes leaves to look green. When the days are long and sunny, leaves use chlorophyll to absorb energy from the sun and convert it into energy for the tree. When the days get shorter, leaves receive less energy from the sun, causing them to lose chlorophyll and their green pigment disappears, revealing red, orange, and yellow pigments underneath! Although these pigments are not visible until chlorophyll disappears, they are present throughout the growing season.

Chlorophyll: Pigment that produces green leaves

Carotenoids: Pigments that produce yellow, orange, and brown leaves

Anthocyanin: Pigment that produces red and dark purple leaves

Does each species of tree always turn the same color?

Deciduous trees, like maples, oaks, and hickories, tend to produce the same colors each fall. Some examples include the Red Maple which turns scarlet red, the Sugar Maple which turns red or deep orange, the Tulip Poplar which turns golden yellow, and the White Oak which turns copper brown.

Why do evergreen trees stay green?

Not all leaves change color in the fall! Unlike deciduous trees that change color, evergreen trees stay green year-round. Leaves of evergreen trees are rolled up into needles with a protective wax-like coating. This helps them hold in moisture and reduces the risk of freezing, allowing photosynthesis to continue in winter, though at a slower rate due to less sunlight.

How does weather impact the changing of the leaves?

Have you ever noticed that the color of the autumn leaves varies from year to year? Although sunlight exposure affects the color of the leaves more than any other environmental factor, weather, temperature, and moisture can also impact the color of the leaves as they change each fall. When there is not sufficient rain through the summer, trees may begin losing their leaves or changing color prematurely. Strong rains or winds in the fall can also cause leaves to fall before peak season. Warm, wet springs followed by adequate rain in the summer and cool, sunny days in the fall tend to produce the most colorful leaves in the autumn months.

Although the red, orange, and yellow leaves are beautiful while they last, they do not stay long! Peak leaf season at Creasey Mahan Nature Preserve is between late October and early November. You are invited to visit to enjoy our beautiful autumn colors!