The question for leaf lookers heading to Eastern national parks is—what’s the foliage forecast for fall 2012?
Well, Dr. Howard S. Neufeld has some good news for you—but the reasons why aren’t simple.
One of the country’s true go-to guys for that kind of insight, Neufeld is a Professor and plant eco-physiologist in the Department of Biology at Appalachian State University (ASU) in Boone, North Carolina. Some of Neufeld’s research aims directly at fall color predictors, including compounds that produce the best color and the impact of water stress on the brightness of fall foliage.
He runs an online report on the topic for ASU ("The Fall Color Guy"), issues foliage forecasts, tracks the color trends and works with southeastern tourism agencies to get the word out.
With record recent warmth and a dramatic drought in many parts of the United States, this year’s forecast for the East involves great color—and most of the factors known to impact autumn’s color.
To be brief, but reasonably thorough, Neufeld reminds us that the leaves turn in the first place because the diminishing sunlight of late summer and early fall degrades the green chlorophyll. That reveals yellows and oranges already present in the leaves.
But Neufeld maintains that a great color year almost always brings brilliant reds to the fore—and that invariably requires that trees have ample sugars available to make anthocyanins, the red pigments. That results from a constellation of factors—ample water, long strings of sunny late summer and early autumn days, and cool temperatures, especially at night (but not below freezing—which can retard the reds).
Some of that is invariably up in the air—we won’t really know how sunny and cool autumn will be till it’s happening.
But Neufeld maintains that a good fall color year is on the way. The best indicator of that, he says, is that the East, and particularly the Appalachians, have had ample to plentiful rainfall, particularly in the Southern Appalachians. The drought in many parts of the country hasn’t had a big impact on favored leaf-looking locations.
The same can roughly be said all the way to New England, and even across the northern tier to Minnesota, but it “has been drier in the north. The good news there,” he says, “some maintain that slightly dry weather actually enhances color.”
Drought is one of the real downers for great color. Leaves wilt to brown, rarely gain the bright red colors, and often fall prematurely. “I don’t think there is anywhere in the Eastern mountains right now where a sudden shift to drier weather would ruin the color,” he says.
Other prescriptions for poor color? “When we have cloudy, warm days,” he says, “those also reduce sugar levels, which limit a tree’s ability to synthesize anthocyanins, and we get duller reds and a shift over to more orange-yellow colors.”
Neufeld finds himself wondering whether the warm spring and summer and early appearance of the leaves last spring might also affect fall color. He particularly wonders about New England, where global warming has raised temperatures more over the last 50 years than has been the case in the Southern Appalachians. “As hard as this may be for me to admit,” he says, “I simply don’t know what scenario will prevail. We’ll just have to wait and see.”
He nevertheless sees a generally typical trend in timing across the region. New England’s color, he says, always peaks first (early October), due to far northern latitude. Then the Southern Appalachians of the Great Smokies and Blue Ridge peak in mid-October, due to those mountains being the highest on the East coast. Then the lower elevations of northern Virginia, Maryland and Pennsylvania generally follow. Of course—the weather, and the color, is not set in stone.
“For now, the shift to fall has certainly started here in the Boone area of the North Carolina mountains, with maples starting to turn, temperatures down into the forties, and nice sunny days. In fact, if this weather keeps up, it’ll be pretty ideal for great color,” he says.
That's what Neufeld predicts for this fall. What do you think? What's it look like for your area?