A refreshing splash of normality is about to enter this disorienting autumn of Zoom classes, quarantines, and masked professors. The annual fall foliage show already is creeping across the woods, and early indications are that it will be more than a pleasant distraction.

“I think this is going to be a very good year,” said Ryan Reed, a Pennsylvania Department of Conservation and Natural Resources forestry expert. He said that in the seven seasons he’s been producing Pennsylvania’s excellent weekly foliage reports, “I think it’s going to be the best.”

It also might be among the most viewed.

The red pigments show off last October at French Creek State Park.
MONICA HERNDON / Staff Photographer
The red pigments show off last October at French Creek State Park.

The pandemic has affected just about everything, and it appears that the foliage season isn’t immune. Tourism officials from the Blue Ridges to the White Mountains of New Hampshire are anticipating a harvest of leaf-peepers.

The Pennsylvania forests were hot destinations all summer, Reed said, and he expects that traffic to continue into the fall. “The increase in visitor use in state forests and state parks has been unprecedented,” he said.

The trend likely will be similar elsewhere, said David Angotti, founder of SmokyMountains.com, a tourism service that produces a national foliage forecasting map annually. Tourists have been favoring cars over planes and cruises.

“Since many of the top fall-foliage destinations are within an easy drive of major cities, we are expecting larger leaf-peeping crowds,” he said.

That has been evident in Pennsylvania, said Chris Barnet, head of the Pocono Mountains Visitors Bureau. The Poconos always have been a popular fall destination, “but we’re starting to see reservations pick up during the week,” said Barnet, adding that might well be a symptom of more people working and studying remotely.

Nature is peeling back the curtain in northern New England, and the waves of oranges, reds, scarlets, russets, and yellows — the triumph of the carotenoids and anthocyanins over the chlorophylls — will be rippling this way over the next several weeks.

Foliage seasons have varied by as much as two and three weeks in terms of onset, peak period, coloration, duration, and leaf-fall, but as of now both Reed and the SmokyMountain people are predicting that this year’s peak will arrive in the Philadelphia region the last week in October.

How do they know?

They don’t know, for certain. It is only a best calculation based on what happened during the spring and summer and how things have played out in recent years.

Behind those pastoral vistas, the stoical trees constantly contend with the chaos and caprice of the atmosphere.

The variables in play — including spring and summer rainfall; forest health; the presence of pests; storminess; and critically, weather conditions from mid-September into October — make it all but impossible to forecast the course of a season precisely, said Marc Abrams, a Penn State professor of forest ecology and a longtime foliage observer.

The overall warming trend, particularly robust in North America, also is affecting the seasons, but increasing temperatures notwithstanding, leaves still must obey the rhythms of the light.

Responding to the weakening sun and lengthening nights, chlorophyll in deciduous trees withdraws, yielding to the carotenoid pigments, the same ones that color pumpkins and corn. In species such as sumac, some maples, and mountain ash, the anthocyanins turn the leaves brilliant variants of red.

The ideal antecedent conditions for coloration are adequate, but not excessive, rains in spring and summer, and not too much humidity, Reed said.

Despite deluges around here in July and August and summer dryness in central Pennsylvania and parts of New England, those conditions generally were met in key foliage regions. Spring rainfall was just about normal, according to the Northeast Regional Climate Center.

And dryness, Reed said, is far better than excessive wetness. He recalled that, in the summer of 2014, his first year of foliage forecasting, relentless wetness in the forests led to a horrific outbreak of the anthracnose fungus, which darkened the leaves. Think of Mummers without feathers.

Symptons of anthracnose, a real autumn show spoiler, on maple leaves.
Maine Department of Agriculture and Forestry
Symptons of anthracnose, a real autumn show spoiler, on maple leaves.

Fortunately, that is not an issue this year.

What can go wrong?

The fate of the season depends on what is about to happen. “So much about fall colors is affected by weather from mid-September to mid-October,” Abrams said. He said that eastern Pennsylvania should be in great shape and that his central Pennsylvania area recently had some leaf-saving rains.

The ideal, said Reed, would be a run of dry weather with sunshine by day and cool, but not freezing, nights; frosts are leaf-killers.

It is impossible to know exactly how that will play out. Weather forecasts tend to deteriorate beyond the seven- to 10-day range.

One way to keep track of the season’s progress in Pennsylvania is to monitor the DCNR foliage site.

Reed updates it every week based on reports from the state’s 20 forestry divisions and observers in all 67 counties, tweaking it based on the extended weather outlooks.

The first report will be posted Sept. 24, but Reed said that for a sneak preview, check out the 2019 archives.

Based on what he has seen so far, he expects the 2020 schedule to be similar. Subject to change.

One thing won’t change: The Philadelphia region is situated within driving distance of some of the world’s most spectacular fall foliage — what naturalist Edwin Way Teale called “the glorious, flaming sunset of the year.”