Conditions promise dazzling fall foliage display, experts say

| Friday, Sept. 27, 2013, 11:41 a.m.

As autumn colors are just beginning to emerge, this fall is shaping up to be a spectacular one for leaf peepers.

“We've had ideal weather conditions with bright, sunny days and cool, crisp nights,” said Dave Planinsek, a forester with the state Bureau of Forestry. “We've had sufficient amounts of precipitation that has the trees coming into autumn in a very healthy state.”

For several years, experts have said the state needed drier and colder weather in order to produce brilliant foliage.

The show is dependent on quite the balancing act — too much rain keeps chlorophyll production going, while too little can stunt the production of starches needed to produce certain pigments. Warmer temperatures can also diminish colors.

Tom Kines, a senior meteorologist at AccuWeather in State College, said there are several dry days ahead. He'd also like to see a few light frosts, which he said can help bring out color.

“What you don't want is rain for several hours,” Kines said. “When the leaves start getting close to peak color, they fall off the trees pretty easily. So you don't want a big wind event, either.”

Peak days

The Laurel Highlands peaks earlier than other areas of the state. Fall colors are expected to be most brilliant there between Oct. 10 and 15, Planinsek said.

In Western Pennsylvania, fall colors will peak between Oct. 15 and 25, he said.

Pennsylvania has a longer and more varied fall foliage season than any other state — or anywhere in the world, according to the state Department of Conservation and Natural Resources.

Only a few regions of the world have deciduous forests that display fall autumn color: eastern North America, the British Isles and parts of northwestern Europe, northeastern China and northern Japan.

Forests in other regions are either tropical or dominated by evergreens.

Why leaves change

Leaves begin to change colors as longer nights arrive and chlorophyll production slows and then stops.

During the growing season chlorophyll, which gives leaves their green color, is continually used, broken down and replaced.

As the chlorophyll disappears, other pigments present in the leave are unmasked.

Tree species have different levels of these pigments, which create the characteristic colors of their leaves.

Oaks turn red or brown; maples turn red; orange-red or yellow; and dogwood turns a purplish red.

Big for tourism

Autumn is an important tourism time for the state.

“This year the mid-Atlantic region is predicted to have one of the best fall seasons ever,” said Diane McGraw, the state's tourism director. “We're very excited about that. It puts Pennsylvania on the map.”

The state does not track the economic impact of fall tourism, she said.

McGraw noted that the commonwealth is known for road trips and the tourism offices across the state are hosting fall events.

The state DCNR is posting fall foliage reports online as well as scenic driving tours.

The Armstrong County Tourist Bureau has sold out its Oct. 5 annual fall foliage tour on the Kiski Junction Railroad in the Schenley section of Gilpin.

“I know in other years it wasn't as many people,” said tourist bureau Director Kevin Andrews. “Once (the peak) happens we have a lot of visitors coming in for that. This area is known for the scenery.”

Jodi Weigand is a staff writer for Trib Total Media. She can be reached at 724-226-4702 or

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