Predicting Fall Color in Arkansas is as Easy as Predicting the Weather
October 1999

By Eddie Fugatt
Department of Parks & Tourism

Each September, we look forward to the coming of fall. Even the most avid sun worshipers are now ready to dig out their long-sleeved shirts and begin planning driving tours and favorite outdoor activities around the changing of the leaves. But predicting fall color is no easier than forecasting the weather. That's why the Arkansas Department of Parks and Tourism has a network of fall color spotters in every region who have volunteered to supply weekly updates. This information is combined into one report, available by 5:00 p.m. Central Time each Thursday throughout the fall, so that everyone can make plans for the weekend. The reports are available by calling 1-800-NATURAL (answered live 24 hours a day) or (501) 682-7777 (normal business hours only). You can also order a fall Arkansas Vacation Planning Kit by calling either of these numbers. Foliage updates and a wealth of other travel information are also available on the Arkansas web site: www.arkansas.com. Travel consultants at the 13 Arkansas Tourist Information Centers located at major entry points into Arkansas also have fall color information in hand to advise travelers. The reports describe foliage changes in these three regions: northwest/north central Arkansas (Ozarks), central Arkansas/Ouachita Mountains, and southern/eastern Arkansas. Specific areas and highways are identified when possible.

Many people wonder what causes the leaves to begin changing color in the fall. Contrary to popular belief, frost does not trigger this transformation. Most of the time, the first heavy frost does not occur until the period of color is nearly over. Two factors are primarily responsible for the colors we see: less light intensity as the earth tilts on its axis and the sun appears to move farther south, combined with warm days and cool nights.

Leaves serve as factories where the tree's food is made. Chlorophyll gives leaves their green color. They use sunlight, carbon dioxide, water and other nutrients from the soil to provide the tree with food. Fall begins as the earth tilts on its axis and the sun's rays become less direct, and a chemical reaction is triggered in the leaves. The foodmaking process slows and chlorophyll breaks down, revealing hues of red and causing other chemical changes, which in turn produce other colors.

Many warm days and cool nights at the beginning of fall are very good for production of red colors. According to Dr. Don Culwell, a University of Central Arkansas botanist: "As the temperature drops, the cell's machinery begins to shut down. Cool nights change sugars to red pigment." Leaves produce some sugars for food during the day, but cooler temperatures at night keep these sugars from moving out of the leaves and into the tree.

The amount of summer rainfall may have less effect on the color of foliage than many people believe. Dr. Culwell says, "Rainfall influences the fall foliage only to the extent that a dry summer may cause trees to be less healthy. If you see bright green, healthy trees in an area, they have a good chance of producing colorful foliage, regardless of summer rainfall totals. If they have dry, brown leaves just before the foliage season, they won't be producing much color." So below average rainfall in Arkansas during the summer does not signal poor fall color. However, if you see large patches of brown in a certain area, you will know that those particular hardwoods will not change this year.

Weather conditions during the period of September to mid-October (in Arkansas) are far more important. For instance, if it's too rainy during this period, we will not have the warm, sunny days or the cool, crisp nights described earlier. If it turns too cold, we will have cool nights, but the lack of warm days will discourage leaves from manufacturing sugars while the sun is shining. If it stays too hot at night, sugars will continue to pass into the tree instead of collecting in the leaf until late in the critical period, when frost or heavy wind may strip the foliage from the trees before much color is apparent. When the right things happen at just the right time, we enjoy a statewide outbreak of the picturebook color that is always present in one area or another each year. Most years, great color appears in different regions at various times between mid-October and mid-November, which is why the weekly updates are important.

Generally, significant color change begins in the Ozarks of northern Arkansas in late September or early October. The trees in central Arkansas and the Ouachita mountain range of west central Arkansas are changing noticeably by early to mid-October. Southern and eastern Arkansas foliage usually begins changing during mid-October. Most people, however, are more interested in the "peak" of color. There is usually a period of a week or so when the foliage in a particular area is at its best.

The peak may be for a large area of the forest, or different areas may peak at different times, even though they are close to each other. Normally, the peak of color occurs around two or three weeks after color changes begin, meaning late October for the Ozarks, late October or early November for central and western Arkansas, and early to mid-November for the southern and eastern sections.

Never wait until the last minute to visit an area of outstanding color. Foliage always looks best just before it is time for it to go away. The colorful leaves do not have much holding them onto the trees, and a good wind, rain, hailstorm, or frost can bring an end to the color in an area in a matter of hours. Another good idea is to plan to stay a few days in order to enjoy driving tours or camping, hiking, canoeing, photography, craft fairs, and other activities.

Set aside some leisure time to experience autumn in Arkansas this year. The weather is cool, crowds are smaller, the fish are biting, and it's one of the best times all year to be outdoors.

This release, along with others by the Department of Parks & Tourism, is available electronically through the Arkansas Press Association Bulletin Board: apa@lr.cleaf.com (in-state only) and the Department’s Web site: www.arkansas.com under media information.