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Predictions are for lots of brilliant color this autumn

| Friday, Sept. 19, 2014, 6:15 p.m.
Beautiful autumn leaves stand out against a bright blue sky.
Tribune-Review
A canopy of colorful leaves in Keystone State Park in Derry Township.
Erica Hilliard | Erica Hilliard | TRIB TOTAL MEDIA
Fall colors highlight the trees in Brackenridge Park.

While the Farmers Almanac is predicting a woeful winter, foresters say the prelude should be a colorful fall.

Moderate temperatures and precipitation this past summer bode well for a vibrant display of autumn foliage, according to Brian Wolyniak, the Penn State Extension urban forester in Allegheny County.

“The weather we've had so far is setting us up for a nice show,” he says. “Conditions over the next month or so also will have an impact, especially if night-time temperatures are cool and we don't get too much rainfall.”

Chilly nights on the dry side tend to promote the most vibrant autumn leaves, Wolyniak says. “If we get a lot of precipitation between now and the end of October, trees could take up too much water, which would dilute the pigments in their foliage.”

The science

Deciduous trees change color in fall when they lose their green pigment to unmask yellows and oranges that have been present throughout the growing season. Some trees also produce reds and purples in late summer, Wolyniak says.

The green pigment is chlorophyll, a biomolecule essential to photosynthesis — the process leaves use to convert sunlight into energy. As trees prepare for winter dormancy, chlorophyll production slows and then stops completely.

That's when yellow and orange pigments called carotenoids are revealed in trees, such as ash, birch, black cherry, sycamore, hickory, elm, pear, sugar maple and tulip poplar, Wolyniak says.

The red and purple pigments — anthocyanins — are produced when the sugar in leaves breaks down in late summer. “Some trees have a mixture of reds, oranges and yellows, but in a small number of trees —like red maples, red oaks, dogwood and sweet gum — anthocyanins dominate,” Wolyniak says.

“The more prevalent the anthocyanins, the more fiery the tree will be. Think of red maple, one of fall's most spectacular specimens,” Wolyniak says. “They're a classic example of why people go leaf-peeping.”

The progression of fall foliage runs from north to south, and typically begins in higher elevations in early October, with trees in valleys following a couple of weeks later, Wolyniak says. “We've had scattered reports of people starting to see color a little early, but most changes probably will occur on a typical timeline.”

Where to go

While city and county parks have a fall splendor of their own, state parks and other large forested areas, like the Laurel Highlands, Oil Creek Valley and the Pennsylvania Wilds may be worth a drive when trees are in their glory.

“We have some of the best fall foliage on the East Coast,” says Julie Donovan, a spokesman for the Laurel Highlands Visitors Bureau (www.laurelhighlands.org/fall). “Fall is huge for us in terms of tourism.”

The bureau posts a Top 10 list of leaf-peeping options that includes the Great Allegheny Passage, a 150-mile bike trail that made the National Geographic Traveler's Best Fall Trips list in 2012, and the Pine Knob Vista in Forbes State Forest, off Route 40 southeast of Uniontown.

“One of my personal favorites is Baughman Rocks Overlook in Ohiopyle State Park,” Donovan says. “You'll see a panoramic view of the Youghiogheny River Gorge — the deepest river gorge in Pennsylvania. It's breathtaking in October.”

The gorge also can be seen from the Frank Lloyd Wright-designed house on Kentuck Knob, located about six miles from Wright's more famous masterpiece, Fallingwater.

Another popular leaf-viewing spot is Mt. Davis in Forbes State Forest, Donovan says. “It's the highest elevation in Pennsylvania. You can overlook valleys and mountaintops in three different states. It's particularly dramatic in fall.”

Folks up for a longer drive will find the Pennsylvania Wilds in the north-central counties offers a double treat in fall, when leaves turn and the bugling of mating elks can be heard. The end of the elk rut overlaps with peak foliage viewing in mid-October, according to Carla Wehler, spokeswoman for the Keystone Elk Country Alliance, which operates the Elk Country Visitors Center (www.pawilds.com).

“The Elk Scenic Drive is ideal for seeing spectacular foliage and the state's elk herd,” Wehler says. “It has 23 viewing sites where you can stop and take photographs. But there are many other two-lane routes through the heart of elk country that people can enjoy, all mapped on our website.”

Deborah Weisberg is a contributing writer for Trib Total Media.

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