SciTech

Where’s the green?

As nature bursts into color this autumn, chemical processes transform leaves, and leaf peepers hike through mountains in pursuit of nature’s deepest hues.

In autumn, large changes come in small sizes.

Frederick Utech, adjunct professor of biological sciences, said that when temperatures drop, autumn leaves form an abscission zone, or a collection of tightly grouped cells within the leaf. As this happens, the leaf’s chlorophyll molecules break down and other pigments show through.

Leaves contain several color pigments, the most dominant of which is chlorophyll, the green pigment that is responsible for photosynthesis. When the chlorophyll breaks down, it produces magnesium, which goes back into the tree to make chlorophyll for next year.

“In a forest, nothing is given or destroyed. That’s basic physics and chemistry,” Utech said.

The color change is also ecological, meaning that it depends on environmental history, selection, and response. The first cool night in autumn usually triggers changes in the leaves’ biochemistry, which lead to different colors.

Part of the reason that autumn landscapes are colorfully transformed is that colors change all at once for deciduous, or leaf-bearing, trees.
“Whether you’re in New England or in the Smoky Mountains or anywhere in between, the appearance of color is synchronized for that area,” Utech said.

Most deciduous forests contain tree species that are generations old. Some of these species have undergone climatic selection, and so they change color at the same time.

“That is why you get the whole hillside in color,” said Utech, pointing toward Schenley Park. You have to gaze beyond Pittsburgh, however, to get the full flavor of autumn colors.

Utech said that color diversity is greater in the south than in the north, because the deciduous forests in New England do not have as many deciduous species as in Pennsylvania. Likewise, the middle and southern Appalachians experience more shades of red than in New England because there are more species in the Appalachian area.

“So the range of colors is going to be quite different in the range of deciduous forests,” Utech said.

The Rocky Mountains, for instance, have only one deciduous species, the aspen, but this species exhibits intense yellow in autumn.

“It’s a little different story than what’s going in the East,” he said. “You’re not talking about all these colors, but it’s still pretty spectacular,” he said.
Utech’s favorite foliage comes from the Great Smoky Mountains in North Carolina. He said that the mountains allow people to see the vertical presentation of leaf colors.

He also recommended taking a day trip to Seven Springs or the Laurel Highlands. There is enough vertical relief in these places, he said, that you get the “feeling of being surrounded by forests.”

A small plane or hot air balloon ride, he said, would also be a good way to see the foliage. “It’s kind of neat to just see all of the colors fly by you.”

You do not have to be airborne, however, to catch a glimpse of the colors. This year, the Tucker County Alpine Festival hosted the 18th Annual Leaf Peepers Festival in Canaan Valley, W.Va., the weekend of September 23.

William Smith, the director of the festival’s information center, said, “It’s a growing festival to celebrate the arrival of the fall colors.”

During the festival, people participate in various events, including hiking, fly fishing, and a golf tournament. Leaf peepers also tour the mountains and take pictures along side roads.

“The festival’s position is to get them here, and after that, they can do what they like,” said Smith. “It’s just a very alive weekend area wide.”

Smith said that the festival is also an opportunity for businesses to sponsor events.

Canaan Valley is popular for its mix of reds and oranges. The reds from maples turn as early as late August, with yellow consistently turning throughout the season.

“I think the colors around here rival what you’re going to find in New England,” Smith said.

But in spite of the West Virginia landscape, thousands of visitors flock to New England each year to catch a glimpse of bright yellows and reds.

According to the Boston Globe’s article “Leaf Peepers Flock to N.H.,” 1.1 million vehicles passed through New Hampshire tollbooths last Columbus Day weekend, right around the time of peak foliage.

“People are very happy so far,” said Vicky Cimino, a spokeswoman for the New Hampshire Division of Travel and Tourism Department.

“Fall is an important season for us. It’s our second-busiest season [after summer]. It’s a billion-dollar season.”

Regardless of location, you will have to plan ahead if you want to catch the peak of fall foliage. Smith said that peak foliage happens nearly overnight in Canaan Valley.

“It’s just that one time when you look out and say ‘Man, this is it,” he said. “It’s just an abstract day.”