Fall color reports available on Arkansas.com

Most of us enjoy the arrival of fall and cooler weather.

But we’re experiencing below average rainfall so far this year. How will this affect the fall foliage season?

When can we expect good color in Arkansas?

Which factors really contribute to color change?

The Arkansas Department of Parks & Tourism has a network of fall color spotters in every region who supply weekly updates.

This information is combined into one report which is available by 5 p.m. Central Time each Thursday throughout the season, so travelers can make plans for the weekend.

Foliage changes in these three regions are described: northwest/north central Arkansas (Ozarks), central Arkansas/ Ouachita Mountains, and southern/ eastern Arkansas. We identify specific areas and highways during peak color times.

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.

Better yet, check our Web site: www.arkansas.com for the same updates, and a wealth of other travel information, ready to study or print at your convenience.

And plan a stop at one of the 13 Arkansas State Welcome Centers at major highway entry points.

Why leaves begin to change

Frost rarely triggers fall foliage. The first heavy frost seldom occurs until the colorful period is nearly over.

Two factors are primarily responsible for starting the fall color process.

The first is the changing of the season.

Plants react to less light intensity as the earth tilts on its axis and the days grow shorter.

To the human eye, the sun appears to move further south on the horizon.

The second major contributor is weather during the critical period of mid-September to mid-October.

Changing seasons

Leaves serve as factories where the tree's food is made. Chlorophyll gives leaves their green color. It uses 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, the sun's rays become less direct, and the days grow shorter. A chemical reaction is triggered in the leaves. The food making process slows and chlorophyll breaks down, revealing hues of red and causing other chemical changes, which in turn produce other colors.

Weather

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 rainfall during the summer has little effect on fall color. Culwell says.

"Rainfall influences fall foliage only to the extent that a dry summer maycause 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 during the summer does not signal poor fall color, nor does an abundance of summer rain insure a more colorful fall.

Most hardwoods enter the fall green and healthy. If a tree has been growing for several years, it is in a good location. It has thrived there through many dry summers.

Weather patterns during September and 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 picture-book color that is always present in one area or another each year. Most years, great color appears in different regions at various times in October and November, which is why the weekly updates are valuable.

Traditional peak color times

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.

But most people are more interested in the "peak" of color, the period of a week or so when the foliage in a particular area is at its best.

The peak may be for a large part of the forest, or different areas may peak at different times, even though they are near each other.

Historically, the peak occurs during late October or early November in the Ozarks, early November in central and western Arkansas, and early to mid-November in the southern and eastern regions. This is an average, and varies from year-to-year.

What signals can we watch for to indicate the beginning of the fall foliage season?

Look for splashes of color in your favorite stand of green hardwoods. Here’s a short list of foliage that changes early in Arkansas, and the color(s) they are likely to display: blackgum (red), hickory (yellow), sassafras (red, orange, or yellow), sweetgum (red, yellow, or purple), red maple (red, yellow, or orange), dogwood (brownish red), poison ivy and poison oak (red), sumac (red), and buckeye (red).

Never wait until the last minute to visit an area of outstanding color. Foliage looks great shortly before peak, too.

Only fragile stems hold the colorful leaves onto the trees, and wind, rain, hail, or frost can bring an end to color in an area in a matter of hours.

Plan to stay a few days, and let the foliage serve as a backdrop for camping, hiking, canoeing, photography, scenic highway tours, craft fairs, fishing, and other favorite autumn activities.

Area, Pages 33 on 09/28/2011