Vibrant fall foliage season expected throughout Pa.
Oct. 1—WILKES-BARRE — Ryan A. Reed, of the Department of Conservation and Natural Resources (DCNR) Department of Forestry said that so far, the growing season conditions have been sufficient to set us up for a very nice fall foliage season.
"It's still too early to say how vibrant it will be, as this depends on the weather in the few weeks before fall foliage season starts," Reed said. "But so far, things are looking good!"
Reed noted the first fall foliage report rolled out on Thursday at www.dcnr.pa.gov.
Reed said the Roaring Creek Tract Drive-Through event is held every autumn in October on the Roaring Creek Tract of Weiser State Forest. Last year, more than 700 vehicles passed through the eight-mile stretch.
DCNR offers several other recommended drives for fall color: Routes 322, 522, 6, 80, 220, 81, 443, 641, 30, 419, 22, 219. And of course, there are many other rural options.
Michael Chapaloney, Executive Director at the Pennsylvania Tourism Office, said the annual economic impact of PA travel and tourism report provides data only on an annual basis. As a result, he said the total economic impact for any particular season is not available.
"However, based on PA hotel performance data from STR, Inc., there is a marked increase in hotel room occupancy and room revenues during the peak leaf peeping month of October compared to the month of September," Chapaloney said. "While both measures typically show a decline in September from summer's highest-of-the-year figures, PA's hotel room demand and total room revenues both typically rebound in October."
Chapaloney said based on data from the past several years, October hotel room demand can increase anywhere from 4% to 7% from September, with room revenues showing similar increases, ranging between 4% and 9% depending on the year.
"PA hotels alone inject between $350 million — $450 million, depending on the year — into the state's economy during the month of October, according to data from STR, Inc.," Chapaloney said.
The Pennsylvania Game Commission sometimes opens the gates in Stony Valley on SGL 211 for a fall foliage tour, which drives through from the Dauphin side to the Gold Mine Road lot. Check the Game Commission's website for a schedule.
DCNR Pa. Fall Foliage Reports
Pennsylvania has a longer and more varied fall foliage season than any other state in the nation — or anywhere in the world.
Only three regions of the world support 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 conifers.
Pennsylvania'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.
Northern tree species include:
Gray and paper (white) birches
Mountain maple
American mountain ash
Quaking aspen
Pin (fire) cherry
Southern tree species include:
Black gum
Black walnut
Pignut hickory
Flowering dogwood
Southern red and scarlet oaks
Sweetbay and umbrella magnolias
Persimmon
Pawpaw
Ohio buckeye, bur oak, and shingle oak, common to the Mississippi Valley, have eastern outposts on the Allegheny Plateau.
How does autumn color happen?
For years, scientists have worked to understand the changes that happen to trees and shrubs in autumn. Although we don't know all the details, we know enough to explain the basics and help you to enjoy nature's multicolored autumn display.
Three factors influence autumn color — leaf pigments, length of night, and weather, but not quite in the way we were told as children.
The timing of color change and leaf fall are primarily regulated by the increasing length of night. None of the other environmental influences-temperature, rainfall, food supply, and so on-are as unvarying as the steadily increasing length of night during autumn. As days grow shorter, and nights grow longer and cooler, biochemical processes in the leaf begin to paint the landscape with nature's autumn palette.
Where do autumn colors come from?
A color palette needs pigments. These molecules capture energy from sunlight to power the chemical reactions that convert water and carbon dioxide into sugars—photosynthesis. Trees in temperate zones store these sugars for their winter dormant period. Three major pigment types are involved in the production of autumn color.
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 russets 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.
Tree species have characteristic colors. Oaks turn red, brown, or russet; hickories show golden bronze; aspen and yellow-poplar, golden yellow; dogwood, purplish red; beech, light tan; and sourwood and black tupelo, crimson. Maples differ by species — red maple turns brilliant scarlet, sugar maple glows orange-red and black maple a rich yellow. But the little striped maple becomes almost colorless. Leaves of some species such as the elms simply shrivel, turn brown and fall.
Why Do Autumn leaves change color?
We are lucky to live in one of the few parts of the world where nature has one last fling before settling down into winter's sleep.
In these lucky places, as days shorten and temperatures become crisp, the quiet green palette of summer foliage is transformed into the vivid autumn palette of reds, oranges, russets and golden yellows before leaves fall off the trees.
Penn's Woods in color
Where to go for help planning your "leaf peeping" day out, visit the "Fall in PA" page at — www.visitpa.com.
You will find a fall foliage web cam, route suggestions and dates of local events across Pennsylvania.
Locate the nearest State Forest or State Park destination at — www.dcnr.state.pa.us.
What triggers leaf fall?
In response to the shortening days and weakening sunlight, leaves begin processes leading up to their fall. 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.
What does all this do for the tree?
Winter is a certainty that all vegetation in the temperate zones must face each year. 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 growing season. Tender leaf tissues, however, would freeze and burst in winter, so plants must either toughen up and protect their leaves or dispose of them.
Evergreens — pines, spruces and other conifers — survive by toughening up. Their needle-shaped foliage is covered with a heavy wax coating and the fluid inside their
cells contains substances that resist freezing. Thus the foliage of evergreens can safely withstand all but the severest winter conditions. Evergreen needles survive for several
years but eventually fall due to old age.
Leaves of deciduous plants, on the other hand, are typically broad and thin and not protected by any coating. They are tender and vulnerable to damage. The fluid in their cells is usually a thin, watery sap that freezes readily. This means that the cells could not survive winter where temperatures fall below freezing.
Tissues unable to overwinter must be sealed off and shed to ensure the plant's continued survival. Thus, leaf fall precedes each winter in the temperate zones Blackgum is one of the earliest trees to turn, showing scarlet leaves in early September in northern Pennsylvania.
When is the best time to see autumn color?
The timing of the color change varies by species. Blackgum begins to show brilliant scarlet branches in late August and the related dogwood is draped in brick-red by mid-September. Maples become red and orange in late September and early October. But oaks only put on their colors long after maples have shed their leaves.
In most years, northern PA counties reach their best autumn color October 1-10. Central counties are at their peak October 10-20 and south central and southeastern PA have the most color Oct. 20-31.
How does weather affect autumn color?
Because carotenoids are always present in leaves, the yellow and gold colors remain fairly constant from year to year. The brilliance of red colors that develop as chlorophyll in the leaves is dwindling can be affected by temperature and soil moisture in late summer and fall.
A succession of warm, sunny days and cool, crisp but not freezing nights seems to bring about the most spectacular color displays.
During the day, sugars are produced in the leaf but cool nights and the gradual closing of veins connecting leaves to twigs prevent these sugars from moving out. Lots of sugar and lots of light spur production of brilliant red, purple and crimson anthocyanin pigments.
Dry soils also affect the chemistry of autumn color. Like the weather, soil moisture varies greatly from year to year and place to place. So fall color will never be the same in any two years or locals. A late spring, or a severe summer drought, can affect the onset of fall color.
Warm fall weather may lower the intensity of autumn colors. A warm wet spring, favorable summer weather, and warm sunny fall days with cool nights typically produce the most brilliant autumn colors.
For more information
Download a copy of the Common Trees of Pennsylvania booklet from Bureau of Forestry web site: www.dcnr.state.pa.us/forestry/
Email questions about Pennsylvania trees and forests to PAForester@pa.gov, or phone 717-787-2703.
Reach Bill O'Boyle at 570-991-6118 or on Twitter @TLBillOBoyle.
