Season for brilliant leaves extended by fortuitous weather in Western Pennsylvania
The tree-covered hillsides and ravines of the Laurel Highlands treated late-season visitors to an unexpected sight this year: leaves.
“There’s still some color now,” said Julie Donovan, spokeswoman for the Laurel Highlands Visitors Bureau in Ligonier. “Fall is very popular in the Laurel Highlands, and without question, the leaves drive a lot of activity. … This season, it actually seems to be extended.”
Warmer fall weather delayed by a few weeks the leaves’ autumnal change from green to brilliant and robust red, yellow, orange and bronze, according to tree experts. A wet growing season built stronger leaves and packed them with starch, a key color ingredient, and there were few October storms.
“A big rainstorm, snowstorm, anything like that when the leaves are ready to drop, kind of puts an end to the fall foliage season in a hurry,” said Dave Planinsek, a Bureau of Forestry forester in Forbes State Forest, which includes the Laurel Highlands.
Instead, Planinsek said, the area saw “the recipe for brilliant fall color”: bright, sunny days and cool, crisp nights.
For leaves to produce the red and purple pigments coloring them during fall, there must be plenty of sunlight during the day and temperatures below 45 at night, said Linda Hyatt, horticulture assistant at the Westmoreland County Extension Service of Penn State University.
“It took us a while for us to get that this year,” she said.
Climate change could be a factor in delaying the fall foliage season, scientists say. A Journal of Tourism Management study by Chinese researchers examined warmer temperatures and leaf color changes over 30 years. It found that color changes in leaves were delayed an average of nearly five days per decade.
Aside from a chilly night in early October, temperatures did not drop into the low 40s until Oct. 19 this year, according to data from the National Weather Service in Moon. Last year, that cool-weather trend started 12 days earlier, on Oct. 7. October temperatures in 2011 and 2013 were similar, but data from 2010 and 2009 show temperatures dipping below the 45-degree threshold during the first week of October.
Nature’s beauty, however, is fickle, and colors were not consistent across Western Pennsylvania, Hyatt said. The wet growing season that kept some leaves on trees longer made others prone to fungal diseases that dropped them a month early. The leaves at Ohiopyle State Park stayed longer, but they weren’t much to look at, said Barb Wallace, the park’s naturalist.
“Even though the leaves were on, they just turned brown,” she said, lamenting the absent reds, yellows and oranges that typically adorn the park. “Which is fine if you like brown.”
Aaron Aupperlee is a staff writer for Trib Total Media. He can be reached at 412-320-7986 or [email protected].