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How to spot the best fall colors in Iowa

The Iowa DNR says peak colors could arrive soon

One of the most exciting things about fall is when the leaves around Iowa start to change colors. 

Often the leaves change from their traditional green colors in the summer to a variety of yellows, reds, oranges, and browns.

Have you ever wondered WHY leaves actually change colors? 

There's a chemical compound inside leaves known as chlorophyll. This is what provides the plants with foods, and it gives them a traditional green color (hence the color of leaves and grass during the summer). But there's a scientific explanation as to why the leaves change colors.

The Iowa DNR provides the following explanation on their website for the color change: 

Other pigments are also present in green plants. They serve as energy absorbers and help chlorophyll do its job. They appear mostly yellow and orange in color but they are not seen much as long as chlorophyll is being manufactured in the leaves. The amounts of these other pigments in various plants depends on the particular tree species, soil acidity, and the availability of trace minerals in the soils where the trees grow. The changing of leaf color is associated with winter dormancy in all perennial plants. A chemical called phytochrome triggers plants to go into the dormant period when nights get long enough. Therefore, day length does trigger leaf color change. One of the things that happens when dormancy begins is development of a corky layer of cells between the leaf stalk (petiole) and the woody part of the tree. This “abscission layer” slows the transport of water and carbohydrates. As this happens, the manufacture of chlorophyll is slowed and the green color in the leaves begins to fade, allowing the other pigments to show through. Since the transport of water is slowed down, food manufactured by the remaining chlorophyll builds up in the sap of the leaf and other pigments are formed which cause the leaves to turn red or purple in color, depending on the acidity of the sap.

--Iowa Department of Natural Resources

The DNR says the brightest colors happen on sunny, fall days with cool, clear nights. Dry weather can also help create a great display of fall foliage. 

Cloudy, rainy, and windy weather can negatively impact fall foliage since it can lead to leaves falling off the trees more quickly, and the pigments inside the leaves don't have enough time to develop because there isn't enough sunlight.

So when is the best time for viewing these color changes? The DNR says that the peak fall colors can occur starting at the end of September.

Northern Iowa usually sees the best color changes between late September and mid-October. Central Iowa tends to see its peak from early to mid-October.

It takes a little longer for the leaves to begin changing in southern Iowa. That typically occurs in mid to late October.

For more information on spotting the best fall foliage in your area, check out the resources on the Iowa DNR's website by clicking here


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