Enjoy the Ashland Succession Trail at Ashland Nature Center in Hockessin, Delaware with the help of our Audio Tour. Follow along with our Trail Guide.
Enjoy the Ashland Succession Trail at Ashland Nature Center in Hockessin, Delaware with the help of our Audio Tour. Follow along with our Trail Guide.
Ashland Succession Trail Guide Printable Booklet
Ashland Succession Trail Guide Audio Tour
Audio Tour Text
Hello, I’m Kate Engleman, a Girl Scout in Troop 4923, and your host for today. I created this audio trail guide as a part of my Gold Award project, in collaboration with the Ashland Nature Center. Today we will be exploring the Succession Trail.
During your hike, I will guide you through the sights and sounds of the trail, and hope to teach you a little bit about the process of ecological succession.
Ashland’s Succession Trail winds through fields, shrub areas, a pine forest, a young woods, and a mature deciduous forest before leading back along the floodplain of the Red Clay Creek.
To hike this trail, simply follow the 34 orange numbered markers. I will be with you along the way, telling you about a different stage of succession at each marker. You will hear about the history of the area, the plants and animals that inhabit each stage of succession, and how modern human interactions affect succession.
Marker 1 is located a short way past the Visitor Center.
Ecological succession is the gradual change in the composition of a natural community over time, like when a field becomes a forest.
Ashland Nature Center and the land that surrounds it were part of a working farm from the mid 1800s until the 1970s. This trail used to be an old farm road, and you can still see the wooden posts and horsegate from this marker. The Ashland Nature Center itself was built where the former barn used to stand. The old stone wall behind the Nature Center building and the silo are all that remain of the barn today.
While succession in this part of the country is often said to begin with abandoned farmland, succession is a cycle, so it has no real start or end. It is also important to recognize that long before Europeans settled on this land, it was once a mature forest inhabited by Native American peoples like the Lenni Lenape.
After farmland is abandoned, grasses and other herbaceous plants usually dominate the area for a few years. The hillside between this trail and the Nature Lodge represents the herbaceous, or field stage of succession. This area is purposely maintained as a meadow by yearly mowing, which prevents woody plants from taking hold.
If you look closely at the hillside, you may be able to see native, warm-season grasses, including big blue-stemmed grass, little blue-stemmed grass, Indian grass, and tall purple top fluffgrass, first established here in a planting project. Besides grasses, wildflowers such as common milkweed, Queen Anne’s lace, thistles, goldenrods, and asters can also be found here.
The grasses that grow on the trail are kept short by regular mowing, as well as by the trampling of human feet, like your own! Mowers and hikers both help set back succession on the trail by preventing other types of plants from growing. The grasses themselves have dense, fibrous roots, and also make it difficult for other plants to grow among them.
While natural succession is sometimes hindered by people, it can also be accelerated under human influence. In 1976, the Delaware Nature Society planted black walnut trees along this trail as part of a bicentennial project. Now, decades later, the original trees have matured, producing an abundance of nuts in the fall. If you look around the larger parent trees, you may even be able to distinguish younger, second generation trees that took root there.
Many Native American nations used black walnut and its bark for medicinal purposes, as well as to make brown and black dyes. Black Walnut sap can also be boiled down to make a syrup.
Use caution if you pick any walnuts up, as they can easily stain hands and clothing!
This area has been left unmowed for many years, allowing woody plants to grow and begin to gradually shade out the grasses and other herbaceous plants that make up the field. Quite fittingly, this stage of succession is called the shrub stage. Berry briars, such as black raspberry and wineberry grow readily here, producing edible fruits enjoyed by animals and humans alike.
Wild grape and oriental bittersweet also grow here, their woody vines wrapping around other plants as they reach up for the sunlight. The brambly thickets and vines of the shrubs in this area provide cover and nesting sites for Gray Catbirds, Northern Mockingbirds, and Eastern Cottontail rabbits.
A steep stream valley, like this one along Wildflower Brook, usually supports trees even in cultivated areas because it is difficult to mow the steep slopes. Red maple, which can be seen at the far side of the bridge, is a moisture-loving tree, and grows abundantly along this creek.
The shade that Red Maples provide helps keep the water temperature cooler, which in turn creates a better habitat for aquatic organisms. The roots of Red Maple trees also help to hold the soil in place along the stream, preventing erosion.
In an attempt to accelerate succession and to replace a once fairly common native species, hundreds of young Eastern hemlocks were planted on this slope by the Delaware Nature Society in the 1970s. However, less than a dozen trees remain here of the many planted.
Because the trees were planted during the early field stage, many of the young trees were eaten by Meadow Voles, White-tailed Deer and Eastern Cottontail rabbits. Even the few large hemlocks that remain here are now threatened by the Hemlock Woolly Adelgid, an aphid-like insect pest that kills the needles and prevents new growth. This reforestation project is one example of a human initiative to help along the succession process that was not successful!
The large black cherry trees to the right of the trail are examples of trees that colonized this area all on their own, instead of being intentionally planted by humans.
Black cherry is an early woody pioneer, meaning that it is often one of the first tree species to take root and grow in old fields and shrub areas. It is successful as a pioneer species because it can grow in almost any type of soil, and is also tolerant of both sun and shade.
Plant species that are not native to the United States are called “alien plants”. Many alien plants are also considered to be “invasive,” meaning that they are aggressive and can outcompete and displace the native species.
This displacement disrupts the natural web of life that native plants, animals, and decomposers evolved with and are dependent on for survival.
Unfortunately, invasive plants can be very difficult to manage and control. Ongoing monitoring and careful plant control are required to protect native species and eliminate the invasive ones.
By now, you are probably familiar with trees like the black cherry, black walnut, and tulip poplar, which are all native species that call this valley home.
Some invasive species growing in this valley are garlic mustard, wineberry, and Japanese honeysuckle, though you may be more familiar with other invasive species common to this area, such as the spotted lanternfly and brown marmorated stink bug.
Look up! The evergreens you see here are white pines. While white pines used to grow naturally here in Delaware, the even spacing of these ones show that they were planted here on purpose.
White pine trees used to be native to Delaware in colonial times, but now only grow natively in northern Pennsylvania and even further North. Global warming and the large-scale clearing of forests led to higher summer temperatures in this area, meaning that white pines were no longer able to naturally reproduce on their own. White pines will still grow in Delaware, but they need to be planted and cared for by people like you and me. So, even though they were once native to the area, the White Pine forest here no longer represents a natural plant community in Delaware.
One way to determine the age of these white pines is to count the number of branch whorls along the trunk, adding about five years to account for seedling growth years. According to this method, these pines were planted in the early 1960s. While these white pines may have brown, dead branches, they themselves are not dying.
Pines are simply shade intolerant, so their shaded inner branches die because they can’t get enough sunlight. The upper, outer branches of the white pines are healthy and green, because they do receive enough sunlight.
Not as many animals live in the pine forest as in the fields and thickets. The soft, pine needle-covered ground is shady, acidic, and poor in nutrients. This allows few plants to grow and consequently offers little food or shelter for animals.
However, some birds, such as Carolina Chickadees, White-breasted Nuthatches, Eastern Screech Owls, and Great Horned Owls, find shelter in the branches, while Red Squirrels and Southern Flying Squirrels build nests of leaves, twigs, and pine needles in the boughs or in tree cavities. Red Foxes also sometimes make their underground dens in this pine forest.
This relatively flat, hilltop area was maintained as an agricultural field for many years. Since then, a wide variety of woody plant species have been able to grow here, including the tulip poplar.
Tulip poplars can be identified by their light green, tulip shaped leaves, and signature orange and yellow flowers.
Although some of the tulip poplars here are taller than the white pines planted in the pine grove, the tulip poplars are actually younger by several decades.
A sun-loving tree, the tulip poplar grows tall quickly in areas like this where there is no shade or competition from other kinds of trees. Once this area reverts completely to a forest, however, young tulip poplar seedlings will no longer be able to compete here, and other tree species such as oak and hickory will gradually become dominant.
At this point in the process of succession, we see mostly woody plants, like trees of all sizes, shrubs and woody vines. We still see some herbaceous plants, like grasses and wildflowers, but to a lesser extent. The wide variety of plant species here makes a great habitat for birds.
Blue-winged Warblers, Common Yellowthroats, and Indigo Buntings nest here in the
spring and summer, while Eastern Towhees, Northern Cardinals, Song Sparrows, and Downy Woodpeckers can be seen here year-round.
The Indigo Bunting sounds like this:
While the call of the Northern Cardinal sounds like this:
As you continue your hike, stop to listen and see if you can hear any of these birds!
On your way to Marker 16, you will pass by a tipi.
Tipis have a rich history with many Native American peoples on the Great Plains. They were large, conical structures covered by animal hide or canvas that could usually accommodate eight to ten people each.
The Lenni Lenape that historically lived in this area actually did not live in tipis, though. Instead, the Lenni Lenape opted to live in villages of round houses, called wigwams, or in longhouses.
Tipis can also be built as survival structures to protect against the elements. The one you will pass is not a traditional Native American tipi, but rather one built for wilderness survival.
Look up at the tall trees growing in the deciduous forest. The upper branches of these trees intermingle, creating nearly complete shade underneath in the summertime. During the process of ecological succession, as young hardwoods mature and take over, an older forest with several layers of vegetation is formed.
Oak, hickory, and beech trees dominate here, and their intermingling crowns form the forest canopy. Below the canopy, younger trees and smaller species over ten feet in height make up the understory, mostly ironwood, American beech, red maple, and flowering dogwood. The shrub layer is composed of shrubs like mapleleaf viburnum, arrowwood viburnum, witch hazel, and spicebush, as well as sapling trees. Ferns and wildflowers comprise the herbaceous layer. Mosses and fungi along with fallen leaves, branches, and nuts make up the litter layer.
Throughout the forest you can find fallen trees and decaying logs. While they may be a nuisance for hikers like yourself, they actually serve a significant ecological purpose.
When large trees fall, they allow extra light to reach the forest floor, so that new growth can take place. Sometimes shade intolerant species begin to grow in the new sunlight. The fallen tree will gradually decay, aided by the action of bacteria, fungi, insects, and other invertebrates, and will return valuable organic material to the soil, creating a good place for other plants to grow.
This forest is developing toward a climax forest. By definition, a climax forest contains only plant species that can reproduce in shade, as the tall trees block much of the sunlight. If free from major natural or human disturbances, the climax forest experiences only small-scale changes as individuals die and are replaced. However, due to human actions like deforestation, or natural disasters like wildfires, the climax forest may eventually be flattened, and the successional cycle will start all over again with grasses!
The deciduous forest of beech, oak and hickory is the climax stage for uplands in northern Delaware.
But, the forest you are standing in right now has not yet completely recovered from being disturbed by farming and logging in past centuries. The presence of shade intolerant species, like the large tulip poplars seen here, indicates that the climax forest has not yet been reached.
On your left here is an American Beech tree. You can identify an American Beech by its smooth, light-gray bark. American Beeches are able to grow in this part of the forest because they are shade tolerant.
Over the years, people have harmed this tree by carving their names into the bark. Carving into the bark makes it more likely that the tree will get infected from fungi or insects, and can even wind up killing the tree. Please don’t do this. Remember to leave no trace on the trail!
At the bend in the trail here, you can see a growth of witch hazel. Witch hazel is a cold-hearty shrub that can be identified by its distinctive, wavy-toothed leaves and trademark yellow flowers that appear in the late fall.
For centuries, Native American tribes have used witch hazel for medicinal purposes, including as a fever-reducing tea and as a muscle treatment. Other groups historically used witch hazel in the practice of “water witching,” using the shrub to locate water underground.
Can you spot the eastern hemlocks here? They are scattered throughout the forest, some along this section of the trail. These hemlocks were planted at the same time as the ones you heard about at Marker 7. But, although more hemlocks survived here, they have not grown as large as the ones in the field because they receive less sunlight.
Eastern hemlocks once occurred naturally in northern Delaware but are now very rare, except where planted. In prior centuries the mature trees were over-harvested and the species, just like the white pine, was unable to regenerate itself in our forests.
Unlike deciduous species that can reproduce by sending up new shoots from old stumps, these conifers must begin anew from seed.
You may be wondering why this trail zigzags back and forth. Switchbacks like this are used when trails are created on steep hillsides to help prevent erosion.
While it may be tempting to take a “desire path” and shortcut the switchbacks, doing so would create a new trail and water would soon carry away much of the soil. Please don’t do this! Your patience will help to keep the trail as is, for everyone to enjoy!
Sweet birch, which is sometimes also called black birch or cherry birch, grows tall and straight in rich, well-drained upland soil. The gray bark is tight, with horizontal
lines, similar to the bark of a black cherry tree.
The name “sweet birch” originates from Native American nations, who would use its sap to make syrup similar to maple syrup, but with a different taste. In the past, the sap of sweet birch was also used in birch beer. Now, its hard, heavy wood is frequently made into furniture.
Although eastern hemlocks were planted throughout this forest, most of the ones planted on the higher slopes have gradually died. Yet, here near the bottom of the forest slope, many of the planted eastern hemlocks are still thriving.
This is probably due to the fact that the lower forest retains more moisture, and also because the very steep slopes prevent the hemlocks from being eaten by white-tailed deer. As you have already learned, hemlocks seem to be one of their favorite snacks!
Animals inhabit each layer of the forest. Songbirds can be heard in the canopy. Woodpeckers search the trunks of mature trees for tasty invertebrates. White-tailed Deer browse on twigs of young trees in the understory and shrub layer. On the forest floor, Eastern Gray Squirrels gather acorns and Eastern Box Turtles, American Toads, and Eastern Red-backed Salamanders prowl in search of worms and insects.
As you continue along the trail, look for a spur trail branching off to the left, very close to Marker 27. This spur trail will take you to see Birch Run at Marker 26. If you do not wish to detour down to the creek, you can continue on to Marker 27.
Birch Run, which is named after the sweet birch trees in these woods, is a tributary of the Red Clay Creek. This stream is used by many forest animals that come to the water to drink and search for food.
In the spring and summer, mayapples, white wood asters, jewelweed, and New York ferns can be seen on the slopes along the trail here. Skunk cabbage can be seen growing closer to the water’s edge. Many other plants and animals live in the stream itself, too.
When you are ready, head back up the spur trail and on to Marker 27.
To the right, you can see an old fence post. This post marked the forest edge in the 1950s. Since then, the forest has crept out more than 50 feet into the field!
This process began when fallen tree limbs restricted mowing along the field edge. Then, tree seeds were carried out into the field by birds, small mammals, and the wind. These seeds took root and began to grow there, and the rest is history!
In the summer, goldenrod, aster, thistle, Queen Anne’s lace, and milkweed are among the many wildflowers seen growing in this field. A wide variety of animals live here too. Butterflies, leafhoppers, grasshoppers, crickets, and beetles abound in the grasses. Meadow Voles, Northern Short-tailed Shrews, Least Shrews, Eastern Moles, and Star-nosed Moles, burrowing beneath or in the grasses, attract predators like Eastern Ratsnakes, Red Foxes, American Kestrels, Red-tailed Hawks, and Great Horned Owls.
Eastern Meadowlarks, Field Sparrows, and Song Sparrows nest here. Eastern Cottontail rabbits and White-tailed Deer also feed in the field, leaving trails and tracks seen year ‘round, and groundhogs dig burrows throughout the field.
This field is mowed every few years to curb the growth of woody plants, thus preventing the natural succession from field to forest.
Not to worry, though! The field is mowed in late winter when birds and other animals are less active.
On your walk, you have seen several “edge” habitats, such as those bridging field and shrub, shrub and forest, and forest and field. The so-called edge effect occurs wherever two or more vegetation communities come together.
The edges between the communities support a greater number and variety of plants and animals than any single community alone. Edge habitats have abundant wildlife because they provide animals with places to feed, rest, play, reproduce, and escape their enemies. For example, in the summer, Eastern Cottontail rabbits feed in the field close to the protective thickets, enabling them to easily escape predators when necessary.
If you were standing here during a major flood, you would witness a raging torrent of water sweeping across the large, flat floodplain of the Red Clay Creek below you!
Besides the obvious harm that flood water itself poses to a community, floods can do other untold ecological damage. Major floods of the past have deposited several feet of sand and gravel on the floodplain, smothering acres of meadow wildflowers and other plants that once grew here. For now, the floodplain has revegetated itself, and the process of natural succession will continue until the next large flood event.
A lightning strike is another natural phenomenon that can affect succession in a plant community. In the early 1980s, this area was part of a regularly-mowed field with a single, large tulip poplar growing on the hillside nearby. When lightning struck the tree in the 1980s, a large limb fell down, preventing mowing underneath the tree.
In time, birds sitting in the tree deposited seeds of various woody plants –including blackberry, Japanese honeysuckle, oriental bittersweet, and wild grape. The tangle of initial vines and brambles grew thick and allowed other woody plants, such as shrubs and tree seedlings to take hold.
Now, a thick growth of black walnut, black cherry, ashleaf maple, and bitternut hickory are growing here and ecological succession will continue – all thanks to a single bolt of lightning.
Pigs and other farm animals were once kept in a fenced area here on the floodplain. When the farm was abandoned, the old animal pens became gradually overgrown through succession.
As you can probably already guess, grasses established themselves first, followed by perennial plants, and finally woody plants, including tree seedlings.
Succession has also been helped along here with planting projects from the Delaware Nature Society. Some of the young trees planted here have wire cages around them to protect them from being eaten by White-tailed Deer.
With numerous large trees now present here, this area is well on its way to developing into a mature floodplain forest.
The trees which grow on the floodplain are different from those found on the hills and uplands. Oaks and beeches cannot tolerate these damp lowlands. Instead, we usually see the moisture-loving black willow, ashleaf maple, sycamore, and green ash. Unfortunately though, most ash trees have been killed off in recent years by the invasive Emerald Ash Borer.
It is clear then that the floodplain climax forest will differ from the hillside or upland climax forest. The particular species that occur at different stages of succession in a given location are determined by many environmental factors, including moisture and soil type.
Turn right before the Visitor Center to walk to the last and final marker.
Congratulations, you made it to the end of the trail! On your walk, you have seen examples of plant communities in various stages of ecological succession.
You have seen mowed grassy paths, fields, shrub areas, young woods, a white pine forest, a mature deciduous forest, and a wooded floodplain.
It is important to remember that the orderly progression from one stage to another can be disrupted at any time by a natural or human disturbance.
Natural disturbances include fire, floods, wind, lightning, disease, and insect pests, while human disturbances include mowing, clear cutting, timbering, and spraying of herbicides. Even the “climax forest” is not permanent or unchanging, but continues to be affected by both kinds of disturbances.
Thank you for visiting the Ashland Nature Center. I hope you learned something new! If you liked this trail (and your narrator), consider hiking the Floodplain Trail sometime, complete with an audio guide just like this one! Bye for now!