WHY LEAVES CHANGE COLOR

Jack Frost can't take all the credit for the tapestry of color in fall leaves.

The Missouri Conservation Departments says it's a complex process that leads to nature's pageantry.

Tree leaves contain cells that create food for the whole tree.

Those cells use chlorophyll, which gives leaves their green color.

The chlorophyll absorbs energy from the sun to turn water and carbon dioxide into sugars and starches to feed the tree.

During the growing season, the leaves look green. But behind the green, there are hidden colors.

Those are carotenoids. They are the same pigments that give yellow and orange color to plants such as carrots, corn and daffodils.

In the fall, shorter days and cooler nights mean there is less energy for making food.

The chlorophyll starts to break down. The green color disappears and the yellow carotenoids can be seen in trees such as hickory, ash, birch, maple, sycamore, cottonwood and sassafras.

The red and purple colors aren't hiding in the leaves. They're created in the fall when sugars are made during warm days and trapped in the leaves during cool nights.

The trapped sugars change chemically into anthocyanins, which appear red and purple.

The more sunshine during the day, the redder the color. That's why shaded leaves will be less red than those that get a lot of sun.

Cloudy weather and warm nights result in less vivid red leaves on maples, dogwoods and other trees.

Trees that don't get enough water during the growing season tend to drop their leaves quickly, often before they turn colors.

If temperatures get too cold too soon, the leaves die before they've shown their fall colors.

In good years, the Conservation Department says, Missouri's fall colors start appearing in mid-September and peak in mid-October.