The Mysteries of Fall Foliage Revealed

Have you ever wondered what makes the leaves change color in the fall? Or why some years are more vibrant than others? It is quite a fascinating phenomenon, and it all starts with the seasonal temperature and day light hour change. In the fall, the days become shorter and the evenings become cooler. This is what triggers deciduous trees (trees that lose their leaves in the winter) to begin their process of preparation for the winter months to come. This is also why the foliage changes color around the same time every year.

abcission layer
Photo of abscission layer and leaf detachment. Photo by Lilly Schelling.

It starts with the expansion of the abscission layer between the stem and leaf, which slowly blocks the movement of water and sugar back and forth between the leaf and stem. This causes the leaf to lose the ability or resources to replenish chlorophyll, which gives leaves their green coloration. The chlorophyll rapidly breaks down and we are left with xanthophylls and carotenoids, which are responsible for the yellow and orange pigments you see on trees like aspen and birch. These pigments are usually present in the leaf throughout the growing season but are masked by the green pigment of the chlorophyll.  Anthocyanins are responsible for red and purple coloration and are created by the buildup of sugars trapped in the leaf. As fall progresses into winter all of the other pigments break down, as the chlorophyll did, and the only pigment that remains are the tannins, which are responsible for the brown color of the fallen leaves – though some trees retain their brown leaves throughout the winter, such as oak and beech.

Factors that affect the color and duration of fall foliage are temperature, sunlight and moisture. Ideal conditions for colorful fall foliage are a good growing season followed by dry, warm, sunny days and cool nights. If there was stress in the growing season, such as a drought or flood, the abscission layer may form early and the leaves will fall off before changing color. Additionally, too low of temperatures (freezing) in the beginning of fall will rapidly break down the products responsible for bright colors and the only pigment left will be brown. Other factors that can affect colorful fall foliage are heavy rain and windy storms, as these conditions will cause the leaves to fall.

When you are out admiring the fall colors this year, try to identify which pigment products are responsible for the colors you are seeing on the trees. A great way to view the fall foliage is from a canoe or kayak, but remember to wear your personal floatation device as the water will be chilly! The New York Fall Foliage Report is a great tool for tracking the color changes across the state:


The United States National Arboretum

Post by Lilly Schelling, OPRHP.


The Folklore of the Woolly Bear

Finding a banded woolly bear caterpillar during a walk in the woods leaves no doubt that autumn is upon us.  These familiar black and reddish-brown caterpillars are larval Isabella moths.

The woolly bears that we see in the fall are the second generation of woolly bears for the year; the first generation hatched out in May.  This second generation of woolly bears emerged back in August.  Since then , they have eaten leaves from a variety of plants from grasses to clover to trees and sunflowers.  Once the cold weather hits, the woolly bear finds a sheltered spot like rotted log, or under a rock, or in a pile of leaves, to overwinter. When the temperatures drop below freezing, woolly bears also freeze.  Fortunately woolly bears have a cryoprotectant, a natural sugar-based antifreeze which protects the caterpillar’s tissues from being damaged when it freezes.  In spring, woolly bears emerge from their sheltered spot, eat a few more leaves then make their cocoons and undergo metamorphosis to become an Isabella moth.

By Andy Reago & Chrissy McClarren [CC BY 2.0 (, via Wikimedia Commons.
Folklore has it that woolly bears predict the severity of the upcoming winter based on the proportion of black and reddish brown banding on the caterpillar’s body.  A thin reddish brown band means we are in for a tough winter.

But is this folklore true?  Dr. C. H. Curran, curator of insects at the American Museum of Natural History in New York City (1928-1960) traveled to Bear Mountain State Park in 1948 to find out.  On a single day, he gathered as many woolly bears as he could find, compared the reddish brown segment to the black segment, then reported his findings and a winter weather prediction to a reporter at the New York Herald Tribune.  Dr. Curran continued his study for eight more years and was never able to conclude whether the woolly bear was able to predict the winter.

More recently scientists have found that the size of the reddish-brown band increases as caterpillar matures and that wet weather increases the size of the black bands.

While woolly bears may not be an accurate forecaster of the upcoming winter, they are still a delight to see during a visit to a park.  Perhaps you’ll see one curled in a ball or looking for the next leaf to eat.

Post by Susan Carver, OPRHP.


See Through the Eyes of the Seneca at the Ganondagan Grassland Management Area

The Ganondagan State Historic Site located in Victor, NY boasts a historically accurate 17th century longhouse and will be opening a new Seneca Art and Culture Center this fall. However, there is a hidden gem at this historic site that not many realize exists! It is the Grassland Management Area at the corner of Boughton Hill Road and School Road which covers around 80 acres (over 60 football fields!) and is one of the most intriguing interpretive areas at the site!

In 2009 OPRHP restored 67.4 acres of the Grassland Management Area to represent oak opening communities in both plant composition and spatial arrangement. The Grassland Management Area has since spread to fill around 80 acres with the native plants seeded back in 2009.

The idea behind creating an oak opening came from Ganondagan’s past. Journal entries from French and English visitors to the site in the mid to late 1600’s described the landscape they saw when visiting the flourishing Seneca town of Ganondagan. Their descriptions of oak openings were used to create a scene that can transport the viewer back in time to when the Seneca were living at Ganondagan 400 years ago!

Oak openings are fire-dependent savannahs (grasslands) dominated by oak trees and are rare ecological areas, especially in upstate New York. The oak opening created at Ganondagan consists of warm-season grasses (grasses that thrive in the heat of the summer), wildflowers and large oak trees along the surrounding wood edge. Spring fire management promotes lush growth of warm-season grasses and oak trees. Controlled fires also suppress grassland succession (gradual changes in plant species in an ecosystem), provide fertilizer in the form of plant ash, reducing plant height to allow sunlight to reach new (young) plants and hinder the development of invasive species. The fire management of oak openings such as the Grassland Management Area have historically maintained their species composition mainly due to wildfires, to utilize this historic management technique OPRHP will be conducting a prescribed burn. A prescribed burn is a well-planned fire managed by trained firefighting professionals with specific plans in place to keep smoke high and away from the public.

Proper permits and permissions have been received for OPRHP staff to conduct a prescribed burn at the Grassland Management Area in spring of 2016. The burn will cover 20 acres in the first year and help maintain the plant communities of the Grassland Management Area that are representative of the Town of Ganondagan in the 17th century.

When you visit  Ganondagan’s oak opening, look for native plants include big bluestem (Andropogon gerardii), little bluestem (Schizachyrium scoparium), Indian grass (Sorghastrum nutans), black-eyed Susan (Rudbeckia hirta), tall white beardtongue (Penstemon digitalis), smooth blue aster (Aster laevis), New England aster (Aster novae-angliae), zigzag aster (Aster prenanthoides), and Indian hemp (Apocynum cannabinum).

Throughout the year, the grassland at Ganondagan are a delight to visit.  In spring, it is a lush open area of low, green grasses where chirps and buzzes can be heard above anything else. In the late summer it transforms itself into a beautiful 8-foot tall wonderland of wildflowers and golden brown grasses with different seed head patterns, where you can watch even the slightest of breezes wave through all 80 acres!

Post by Whitney Carleton, OPRHP. Photos by Whitney Carleton and Alexis Van Winkle, OPRHP.


Forest Health Specialists: Climbing in Pursuit of Invasive Insects

Forest Health Specialists are an important part of New York State Park’s Invasive Species Management Team. Their work helps protect native plants, wildlife  and forests that are currently being threatened by two non-native invasive species: Hemlock Woolly Adelgid (HWA) and Emerald Ash Borer (EAB). Although these insects are very different from each other in appearance and behavior, they both cause significant destruction and mortality to their host trees.

What do Forest Health Specialists Actually Do?

The Forest Health Specialists are seasonal employees that travel throughout New York State conducting invasive species surveys and monitoring infestations in various Parks. They have training in field biology, forestry, and tree climbing. The team of two camps at the park of interest while completing their work. Surveys involve lots of hiking and investigating trees that look to be in poor health, taking photos, and recording information on location and observations made at each site.

Although hiking in the woods isn’t a bad way to spend a work day, monitoring infestations of HWA is where the job really gets interesting. Specialists need to collect canopy samples from hemlock trees in order to see if insect numbers are declining or increasing. So, using a giant 8-foot slingshot, a line is shot high into the tree to a branch anywhere between 50 to 90 feet above the ground. Then a climbing rope is attached and pulled into the canopy and the fun begins! The Specialist, equipped with a harness and two ascenders (the name for special clips), climbs the rope upwards into the treetop. Climbing can be highly physical but is always rewarding.

A Forest Health Specialist working their way up to the canopy using a climbing harness that is attached to the rope. Climbs typically take about an hour.
A bird’s eye view looking down from the top of a hemlock. The tiny speck at in the bottom (in the green shirt and white cap) is the other team member!

So What’s the Goal?

The goal of this program is to get a better grasp of where these invasive species are spreading, assessing their impact on the forests, and ultimately taking action to slow their spread and keep their numbers under control. It also allows biologists and managers to anticipate other impacts to wildlife or rare species; to plan for potential avoidance or removal of hazard trees along trails; and to help others understand changes they see in the forest and landscape around us.

Of course a key component to the program’s success is you! By offering educational programs and volunteer opportunities, Forest Health Specialists also help people all over the state learn about invasive insects. The more people participating in and understanding invasive species in New York; the better chance we have of making a difference in our parks and our communities.

Remember, the best way to stop the spread of Emerald Ash Borer and Hemlock Woolly Adelgid is to avoid introducing them in the first place. Don’t move firewood, take caution in moving landscaping debris around, and clean equipment and vehicles if moving from a site with these pests to somewhere else!

For more information go to NYS DEC website:

Post by Kelly Blood (OPRHP). Photos by Kelly Blood and Alyssa Reid (OPRHP).


Saving the Sand: Great Lakes Dunes Stewards

It’s a summer day on the eastern shores of Lake Ontario.  As a visitor walks down the beach they observe the sparkling of the water, the crashing of the waves, and the laughter of people as they enjoy the beach.  Parallel to the water runs a series of fencing and signs that mark the perimeter of the remarkable dune ecosystem that lies just behind.  This seventeen mile stretch of Lake Ontario is home to the most expansive dune ecosystem in the state of New York.  The dunes are large sand hills that are held together by extensive plant root systems.  They not only serve as habitat for a variety of species, but as a vital buffer between the power of Lake Ontario and the intricate system of ponds, marshes, and waterways that reside on the other side of the dunes.

The Dune Steward Program was established in the mid 1990’s to help protect this fragile dune system by maintaining the fencing and signs, removing litter, working with wildlife biologists and technicians on a variety of projects, and most importantly interacting and educating the public on the importance of the dunes.  The stewards patrol the 17 mile stretch of coastline that includes El Dorado Nature Preserve, Black Pond Wildlife Management Area (WMA), Lakeview WMA, Sandy Pond Beach, Southwick Beach State Park, and Deer Creek WMA.  Every summer the Department of Environmental  Conservation (DEC) in conjunction with New York State Office of Parks, Recreation and Historic Preservation, The Nature Conservancy, and The Student Conservation Association (SCA), places three interns from across the country to work as dune stewards.  Dune stewards are current students or recent graduates who have a background in environmental conservation.

edited black pond
Beach and dunes at Black Pond WMA. Photo by Jennifer Brady.

Along with the duties described above, this program allows the stewards the opportunity to be involved in other conservation efforts.  Some of these projects include placing identification bands on birds, identifying and monitoring invasive and endangered species, bird surveys, educational events, and a variety of environmental training opportunities. This year the stewards were able to assist in the successful protection of the piping plover, a federally threatened shorebird species.  This small bird lays its eggs in shallow scrapes on grassless beaches or dredged soil areas.  This summer was the first time in over 30 years that the piping plover has nested on Lake Ontario.  Stewards talked to visitors about the plovers and what they can do to assist in the protection of the bird and its chicks. They advised that visitors maintain a respectful distance and keep dogs on a leash when walking through areas where the plovers were nesting.

Piping Plover
An adult piping plover and its day old chick. Photo by Elizabeth Truskowski, DEC.

One of the most important aspects of this program was public interaction and education.  Each day visitors see the work that the stewards are doing and often approach the stewards to ask questions, express concerns, or even just to thank them for the work they are doing.  “It is extremely rewarding to be able to share what we know about the dune environment and its inhabitants to hopefully be able to protect this area for the considerable future,” said Jennifer Brady, DEC dune steward.

Post by Jennifer Brady, DEC Dune Steward, Student Conservation Association (SCA).



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