Something Wild: Conditions are Right for Spectacular Foliage

Dave Anderson, Senior Director of Education at the Forest Society, loves it when people are paying attention to trees. He admits he always finds the foliage in fall, his favorite season, worthy of appreciation. But this year he’s making a bold prediction.

“I'm willing to go out on a limb here and say that this year's fall foliage display could be the best that we've seen in the past decade,” says Dave Anderson, co-host of Something Wild.

But why is Anderson willing to predict an especially colorful fall season this year? “We had a ‘Goldilocks’ summer. Not too wet, not too dry, not too many insect outbreaks, and there's a lot of green leaves remaining on the trees at Labor Day weekend,” he says. “And all those leaves are going to change slowly over the next couple of weeks.”

Anderson argues that peak foliage is more of a procession than a moment. “Peak foliage in people's minds is almost like the eclipse… there was a moment of totality. Foliage doesn't work like an eclipse.”

Chris Martin, Something Wild co-hosts, travels the state in his work for NH Audubon, and is a bit of a foliage connoisseur. “I think that there are peaks. It's not just one peak. I mean, there's this brilliant red, which I think is from red maple trees or swamp maples. Six weeks later, there's this bronze that comes over the hills from oaks or hickory. That's already two peaks, six weeks apart.”

Foliage in New Hampshire varies with your latitude and your elevation. Anderson explains there are other factors as well, including what type of forest you're in, which varies with soil type. “So are you in the dry outwash plain of the seacoast, or are you in a rich mesic forest of the upper valley with a lot of maple?” says Anderson. “Bronzes are oak forests in southern areas and the coastal plain, whereas the bright reds that come on…they're already starting in September in wetlands.”

“And there's this orange color. Where do we find that?” asks Martin.

The different colors of the foliage differ in how they are produced. “Orange and yellow have been there all along,” says Anderson. “You just didn't see it. It was masked beneath the green chlorophyl in the leaves all summer. And it's only when the chlorophyl starts breaking down in the fall in response to shorter days and longer nights that we see the secondary pigments revealed. And those are the yellow and orange.”

But that’s not how it works for red, says Anderson. “ Especially in the rock stars of the foliage world, sugar maples, and earlier in wetlands, the red maple. The reds (and the purples that we see in apple skins and grapes) are manufactured from sugars trapped in the leaf.”

Anderson explains the process: “As the trees begin to prepare for losing their leaves, they form a corky layer at the base of the leaf stem, which is called a petiole.” The corky layer traps the some sugars in the leaf so they can't store it in the the roots.”

“And they convert it to starch which is more stable than sugar. And then they reconvert it to sugar next spring and send it up through the trees.”

“This is where the weather plays a role, according to Anderson. “In the presence of sunlight in the fall, the trees convert that trapped sugar into brighter colored pigments.”

The only spoiler - a hurricane that strips the leaves off the trees, or prolonged rain that dims colors due to a lack of sunshine.

“When I envision peak foliage,” says Martin, “happens in the mountains where you've got balsam fir and white spruce, that stay evergreen, mixed right in with those brilliant maple trees, and maybe the yellow birch, too, creating a contrast between the dark green and the colors.”

“Add in a little frosting of snow in the upper peaks of the Presidential range,” says Anderson, “and you've got the quintessential fall White Mountain postcard.”

Something Wild is a joint production of the Society for the Protection of New Hampshire Forests, NH Audubon and NHPR.