Wisconsin Fall Color Report

WREX-TV will be teaming up with the folks at TravelWisconsin.com to provide you with information on this season's fall color.

This weekend, fall color will begin to take on vibrant shades of orange and yellow in the Northwoods.

Have you ever wondered why leaves change colors, specifically bright reds? The weather actually plays a role! Read on:

(Excerpt from Wisconsin Department of Natural Resources)The temperature and cloud cover can make a big difference in a tree's red colors from year to year.

When a number of warm, sunny autumn days and cool but not freezing nights come one after the other, it's going to be a good year for reds. In the daytime, the leaves can produce lots of sugar, but the cool night temperatures prevent the sugar sap from flowing through the leaf veins and down into the branches and trunk. Anthocyanins to the rescue! Researchers have found out that anthocyanins are produced as a form of protection. They allow the plant to recover nutrients in the leaves before they fall off. This helps make sure that the tree will be ready for the next growing season. Anthocyanins give leaves the bright, brilliant shades of red, purple and crimson.

The yellow, gold and orange colors created by carotenoid remain fairly constant from year to year. That's because carotenoid are always present in leaves, and the amount does not change in response to weather.

The amount of rain in a year also affects autumn leaf color. A severe drought can delay the arrival of fall colors by a few weeks. A warm, wet period during fall will lower the intensity, or brightness, of autumn colors. A severe frost will kill the leaves, turning them brown and causing them to drop early. The best autumn colors come when there's been:

• a warm, wet spring
• a summer that's not too hot or dry, and
• a fall with plenty of warm sunny days and cool nights.