Bucks County fall foliage report: Looks like a bright but shorter season of color

Fall foliage will glow short and bright in Bucks County this year, according to state foresters.

The shift to yellow, orange and red has already begun, but the best time to see autumnal leaves in Bucks County may be mid October, said Kelly Sitch, an ecologist with the Pennsylvania forestry bureau.

Leaf peeping season in Bucks County may be slightly shorter this year because of the dry weather, said Ryan Reed of the state forestry bureau, though he's hopeful the recent rainfall will help extend it. Trees drop their leaves in the fall to conserve energy and moisture, Reed said. When the soil is drier to begin with, the leaves drop faster.

"Trees sort of have this long-range view," Sitch said. "There’s no point in holding onto crispy leaves that don’t photosynthesize" when they can just drop the leaves early and wait for next spring.

The trees people tend to notice most — on the edges of forests beside roadways — go bare faster for the same reason, Reed said. The soil there gets more sunlight, and dries out faster. For longer-lasting foliage, take a half-mile hike into a nearby state park, the forester said.

Warm, sunny days and cool nights produce the brightest foliage, according to the national forest service. That's because the sun boosts sugar production in the leaves, while the cool weather encourages the trees to begin closing off their veins to the leaves, trapping the sugar, according to the USDA.

This year's foliage should follow the state's 2023 maps fairly closely, Reed said, though he predicts the season will happen earlier than last year. Bucks County's leaves began changing in early October last year, according to the foliage report. But this year, leaf color change began as early as mid-September.

The September shift is earlier than in recent years, Reed said, but it's actually more historically normal. Just a few decades ago, southeastern Pennsylvania tended to see an early fall cooldown to usher in leaf peeping season, Reed said.

Warmer fall temperatures of the past few years may have delayed the leaf drop process, Reed said, but with the cooler nighttime temperatures coming next week, we may begin to see more significant changes by mid October.

More: Take a walk through Neshaminy State Park in Fall

Why are fall leaves different colors?

Deciduous trees produce chlorophyll that make their leaves green. But longer fall nights lead trees to slow their growth and produce less chlorophyll, revealing other pigments, like carotenoids and anthocyanin, that are present in the leaf. Carotenoids are responsible for yellow, orange and brown colors, while anthocyanin, which tends to build up in the fall as sugars get trapped in the dying leaves, produces red and purple, according to the USDA.

What makes Pennsylvania's fall foliage special is the diversity of color-changing tree species, Reed said. The state has not just the northern hardwoods, like maple trees, that New England is known for, but also hickory and oak, the leaves of which turn a deep red and add variety to fall colors.

Southeastern Pennsylvania forms the northern edge of the natural range for several types of southern deciduous trees, said Sitch, including willow oak, southern red oak, and sweet bay magnolia.

Bucks County's foliage is also heavy on beech and poplar trees, Becker said. Our autumnal views benefit not only from native species, but also introduced ones like Japanese maple, which can turn bright red, Becker said.

And it's not just the trees, Sitch said: native shrubs like sumac, viburnum and spice bush turn red and gold this time of year. Fall wildflowers are also in full bloom, including goldenrod and aster.

The state's first fall foliage report of the year is set to publish on Thursday. To see the best colors, Reed recommends watching for a county to be reported as "approaching best color." The following week, he said, is usually when that area will peak.

For the past two years, Bucks County's peak foliage has come in late October, according to the state reports.

More: Bucks County hotels, sites prepare for leaf peepers. When will colors peak in fall 2024?

Reporter Jess Rohan can be reached at jrohan@gannett.com.

This article originally appeared on Bucks County Courier Times: Fall foliage in Bucks County will bring bright colors, but short season