If there's one consolation about summer ending, it's that the shorter days mean Butler County is entering into its peak period for fall leaf colors.

The dwindling daylight hours are causing trees to trade their uniform drab greens for pops of red, yellow and orange.

And, according to environmental education specialist Mike Shaffer for Moraine and McConnells Mill state parks, this autumn's leaves might be brighter than normal.

Shaffer said, “The best conditions is to have an adequate amount of rain in the summer and the fall. It all comes down to warm daylight temperatures, and it definitely needs to cool off at night, and you will have a more spectacular leaf show.”

He added despite the near-drought conditions that were present in Butler County for part of the summer, the foliage color should be pretty good this year.

But it won't be sudden.

“It's starting to turn and it should be pretty good this year,” he said. “It's going to be kind of gradual this year, at least in the drought-prone areas,” he said.

But Shaffer predicted peak autumn foliage colors would come during the second and third week of October.

The Pennsylvania Department of Conservation and Natural Resources' Bureau of Forestry's fall foliage map indicates Butler and surrounding counties are entering peak color phase starting next weekend.

According to the state DCNR, three factors influence autumn color —leaf pigments, length of night, and weather.

The timing of the color change and leaf fall are primarily regulated by the increasing length of night. None of the other environmental influences — temperature, rainfall, food supply — are as unvarying as the steadily increasing length of night during autumn, according to the DCNR.

As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to change its color.

Different trees will have different fall colors, said Shaffer.

“Deep reds are maple trees,” he said. “You have red maples which is the most common tree in Pennsylvania.”

Birches and hickory trees usually burst out in yellow leaves.

Shaffer said sugar maples' leaves turn yellow or orange in the fall, depending on how much sunlight the leaves got.

“Sassafras can go orange or yellow. Some trees will produce multiple colors of leaves,” he said.

According to the DCNR, three major pigment types are involved in the production of the autumn colors of leaves.

Chlorophyll is the most abundant pigment. It absorbs red and blue light and reflects green giving leaves their basic color and masking lighter shades.

Carotenoids, (carotene and xanthophylls) reflect orange, yellow and brown colors in corn, carrots, buttercups and bananas.

The clear yellow of tuliptree leaves and the russet shades of oaks are due to carotenoids.

Anthocyanins give red, blue and purple colors to cranberries, apples, grapes, berries, cherries and plums, depending on their acidity. They are water soluble and dissolve in the fluids of leaf cells.

Chlorophyll and carotenoids are present in leaf cells throughout the growing season. Most anthocyanins are produced in the autumn, in response to bright light and excess plant sugars within leaf cells.

During the growing season, chlorophyll is continually used, broken down and replaced and leaves appear green.

As night length increases in the autumn, chlorophyll production slows and then stops. Eventually all the chlorophyll is destroyed. Carotenoids and anthocyanins present in the leaf are then unmasked and show their colors.

“Oaks will be the last ones to change,” said Shaffer. “Their leaves are purplish red and they will hold their leaves.”

At least until the leaves inevitably fall from the trees, he said.

That's because in response to the shortening days and weakening sunlight, the veins that carry fluids into and out of the leaf gradually close off as a layer of cells forms at the base of each leaf.

These clogged veins trap sugars in the leaf and promote production of anthocyanins. Once this separation layer is complete and the connecting tissues are sealed off, the leaf is ready to drop.

A lot of this leaf lore is covered by Shaffer in the popular fall foliage kayak floats at Moraine and fall foliage hikes at McConnells Mill.

Shaffer said the kayak trips and hikes of been popular programs at the state parks for the past 21 years.

And why not? This is one of the best areas in the country for viewing fall foliage.

Shaffer said, “We have a lot of diversity in trees. We do have some excellent fall foliage in Pennsylvania.”

According to the DCNR, the state's location between 40° and 42° north latitude and its varied topography from sea level on the coastal plain to over 3,000 feet in the Laurel Highlands supports 134 species of trees and many more shrubs and vines that contribute to the display of autumn color.

Pennsylvania is the meeting ground of northern trees that flourish only on mountain tops farther south and southern species that are at the northern limits of their range.

As to why trees shed their leaves every fall, DCNR forestry experts say it's a survival mechanism.

Winter is a certainty that all vegetation in the temperate zones must face each year, according to the DCNR. Perennial plants, including trees, must protect themselves from freezing temperatures and desiccation.

Stems, twigs, and buds are equipped to survive extreme cold and will reawaken when spring heralds the start of another year.

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