|Kettle Hole Trail
The Kettle Hole Trail is a pathway through one of the most ecologically significant ecosystems in the United States. The early settlers of Long Island considered the dry, sandy soil, left behind from the great continental glaciers of 20,000 to 2,000,000 years ago, barren because of its high acidity, great porosity and virtual absence of humus. While the combination of these factors made growing crops on it nearly impossible, the Pine Forests are far from "barren". They contain the greatest concentrations of rare, threatened and endangered plant and animal species in New York State.
In addition to its ecological rarity and diversity, the Pine Barrens overlie large underground reservoirs of potable drinking water called aquifers. The great porosity of the soil allows rainwater to quickly percolate through the ground and keep the aquifers full. The absence of development in the area, due in a large part to the "barren" nature of the soil, keeps the water pure. At different locations throughout the Pine Barrens, the surface elevation dips below the water table, so that this pure water forms lakes, ponds, swamps, marshes and bogs. While some of this water is used for drinking, much of it slowly flows into the surrounding bodies of water, that is northward, eventually draining into the sound; eastward, eventually draining into Peconic Bay; or southward, to drain into the Atlantic Ocean.
The specialized ecology of the Pine Barrens developed as an adaptation of the underlying geology. The sandy to gravely sediments found beneath the Pine Barrens were deposited as glacial outwash, left behind by the continental glaciers that covered much of North America during the Pleistocene Epoch. Outwash sediments are carried and eventually deposited by streams that flow off of a melting glacier. The Kettle Hole trail also traverses a glacial moraine. A moraine is a geological feature that is formed when sediments are deposited at the front of a paused or receding glacier. Paused or receding glaciers are melting, but at rates equal to or less then the rate of advance of the ice. Moraines can be further shaped by glacial-tectonic forces-forces derived from the weight and movement of the glacier itself.
As you walk through the Pine Barrens, use all of your senses to make observations of your surroundings. Not only does the Kettle Hole Trail allow you to observe a rare ecological system up close, but it also offers you the opportunity to see an undisturbed and unaltered view of Long Islands environmental and geological past.
The Kettle Hole Trail begins at the northwestern edge of the Peconic Buildings parking lot at Suffolk County Community College. Before you enter the trail, look southward. Here you can see the relatively flat topography of the outwash plains. These broad, fan shaped terraces that gently decline in elevation until they reach sea level were formed from meltwater streams flowing from the receding glacier. If the streams originated at this point, where would the coarsest or largest-diameter sediments be deposited? The finest or smallest-diameter? Streams are usually flowing faster near the glacier and slower away from the glacier.
The entrance to the Pine Barrens Kettle Hole trail begins here. At the very edge of the wooded area are sweet ferns, which are not really ferns at all. True ferns reproduce by spores, small round reproductive cells that look like miniature doughnuts which are found on the underside of their leaves. Examine the underside of sweet ferns leaves. Can you see any spores? They are actually members of the bayberry family and reproduce by seeds.
Notice the Pitch Pines that are growing at the edge of the woods. Their size increases towards the forest. Can you think of a reason for this? Notice their pine cones, or seed containers are open. Where are the seeds? It is nice and sunny here with little competition from neighboring plants. A seed dispersed will most likely be successful in gathering the needed nutrients for growth. That means there is no reason for a tree to hold on to its seeds for better conditions to occur.
Also notice the Scrub Oaks along the edge. Scrub Oaks can endure frequent fires but they cannot endure too much shade. Areas were Scrub oaks thrive are often very dry, with sandy, poor soil and a high likelihood of forest fires-which kill of their competition.
Pitch Pines are the most fire resistant-tree in the Northeast. Pitch Pines within the Pine Barrens often have pinecones with closed or serotinous scales. The cones are closed because the tree waits for the best conditions for germination and growth before it releases its seeds. During a fire these cones open and drop their seeds. Remarkably, the best conditions occur right after a forest fire, when heat resistant plants that would compete for the limited nutrients in the soil are destroyed. What does the growth of Pitch Pines tell you about the likelihood of fire in the Pine Barrens? Look around. Are there any small, young Pitch Pines growing? What is the most common size? Was the last fire recent?
The occurrence of White or Black Oak trees indicate that there is more soil moisture available. Notice that there are few Scrub Oaks growing in this area. Remember, Scrub Oaks thrive in areas where the soil is coarse and sandy with little moisture and high burn potential, but do not grow well in shade. Scrub Oaks are among the first plants to regrow after a fire, but as the forest ecosystem matures they are crowded out by other species which grow taller and block the sunlight. You are still on outwash, so the soil is suited for their growth, what then, does the limited number of Scrub Oaks growing here indicate about the maturity of the woodlands?
Bracken Fern is a hardy plant that can withstand fire because its rhizomes, or underground stems and roots, are very deep in the soil. It grows throughout the Pine Barrens and provides shelter to a variety of wildlife, including white tailed deer. Examine the underside of the leaves. Are there spores? Is this a true fern?
Blueberry and Huckleberry are two of the most common plants found in the Pine Barrens. Like all other plant life growing here, they both can survive fairly frequent burns. Although they both look alike, Blueberries are sweeter and Huckleberries have a grittier taste due to their larger seeds. Check the undersides of the leaves- Huckleberries have small resinous dots there. If it is late July or August, taste the berries. Which are sweeter?
Notice the wide path that crosses the Kettle Hole trail. This is most likely an old wagon trail that might have originated as an Indian path or, before that, a deer trail. Today, many people explore these trails in order to find old garbage dumps. Old bottles are highly prized. What was once discarded junk of our ancestors is now thought of as valuable antiques. What might some of the discarded garbage be? Is littering a modern tendency?
Notice that there are Pitch Pines and Scrub oaks growing in this area. What does that indicate about the soil composition? The burn potential? Notice the canopy or tallest treetops are sparse, allowing insolation or incoming solar radiation to penetrate all the way to the forest floor. This makes the soil temperature of the Pine Barrens quite warm, as much as 20 degrees warmer than an average hardwood forest. Dig into the leaf litter. How do the different layers feel? Which is drier? Is there much decomposition or decay apparent? The hot, dry temperature and the acidic, sandy composition of the soil actually discourages decay of the leaf litter. The dry leaf litter turns into kindling, waiting for lightening or some other spark to ignite it. What should hikers never do in the Pine Barrens?Stop 8
This tunnel goes underneath Ring Road. Swallows nest in the lights inside of the tunnel. Stop for a moment and listen. What causes that noise? Look at the structure of the inside of the tunnel, especially the round shape and closely spaced "ribs". Have you ever blown air into a ribbed drinking straw? What happens when you do?
The trail divides at the outer rim of the Kettle Hole. The Kettle Hole is an irregularly shaped depression that is formed when large chunks of ice are left behind by a receding glacier. These chunks of ice are covered by outwash sediments that are carried off the melting glacier in streams of fast moving water. The ice eventually melts, forming depressions in the sediment. The depressions become lakes when the elevation of the bottom of the kettle hole is beneath that of the water table. This one is a dry hole. What does that indicate about the elevation of the water table? The water table in this area is at 20 feet above sea level. The bottom of this kettle hole is 100-foot above sea level. How much deeper would the hole have to be in order for it to be a kettle lake?
We are now at the bottom of the Kettle Hole. We have descended about 60 feet in a distance of about 250 feet. The total width of the Kettle is about 700 feet. Look around. If you are truly at the bottom of a depression, all of the surrounding area should be higher then you are. Are you at the bottom?
Bear left on the divided trail. The vegetation here is different then what we have been seeing. The grass is Beard grass and produces seeds that point down with twisted spiral tails. This is to help the seed "drill" itself into the ground and reach moisture when they fall from their stalks.
Here are also some Beech and Poplar trees. Their growth indicates richer soil, and less frequent burns. Also, the Pitch Pines in the area are quite large and straight. Pitch Pines that have been through frequent burns are often stunted and twisted. What could be some reasons why this area seems to have been burned less often then the surrounding, higher area?
The leaf litter on the path in this area is sparse enough to see the underlying soil. Notice that the appearance of the soil is changing. The layer of sediments is now very high in silt and clay, and can therefore hold more moisture. There are also many different sizes and types of rocks mixed randomly into the finer sediment. When the great continental glaciers moved down from the north, they pushed, plucked and scooped up and mixed together great volumes of rocks, gravel, sand and clay. As the glacier melted, these randomly mixed sediments would be released from the ice, to be directly deposited into a mostly unsorted, unconsolidated layer near the base or front of the glacier. This unsorted mix of sediments is called glacial till. On Long Island the till layer is no more than a few feet thick. Dig into the till. Does it feel different then the sediments found in the outwash? Look around at the vegetation. The large deciduous (leaf loosing) trees are mostly Red and White Oak. Mature Oaks indicate richer soil. Are there many more Oaks then Pines? Remember the vegetation found at the beginning of the trail, on the outwash. Is this soil richer then the outwash?
You are now at the northern rim of the kettle hole. Imagine the size of the ice chunk that produced such a large hole.
You are now hiking on the Ronkonkoma Moraine. A moraine is a topographic feature formed by a glacier. As the glacier ice moved forward it incorporated underlying sediments. These sediments would be deposited at the front of the melting glacier in mounds and ridges. If these mounds and ridges are of significant elevation and continuity, they are called moraines. Glacial tectonics-the force of the massive ice shoving and pushing sediments ahead of it also contributed to the development of the ridges in a moraine. Look on your map. Can you see the edge of the moraine? How is the topography of the moraine different from that of the outwash plain?
These large boulders are glacial erratics. When the glacier moves down from the north, it has the ability to carry or shove immense rocks in the direction that it is moving. These rocks are often scratched, chipped or fractured as they are tumbled together between the ice and the underlying formations. The scratches are called striations, while the round fracture marks are called chatter marks. Can you find any marks on these rocks? Look at some of the smaller ones.
The larger rocks are igneous (formed when molten rock or magma cools and hardens) or metamorphic rocks (formed when pre existing rocks are subjected to intense heat and pressure often associated with tectonic deformation). Granite is a type of igneous rock that forms when magma takes a long time to cool-so long that large crystals have time to grow. Basalt is a type of igneous rock that cools quickly-so quickly that that all of the minerals are too tiny to be identified by the naked eye. Finally, a gneiss is a metamorphic rock that has undergone deformation at high temperatures and pressures so that light and dark layers of minerals form. Can you identify which of the large rocks are granite, basalt and gneiss?
Notice that the flora or plant-life has changed again. Notice that the trees are almost all Pitch Pine. Remember, pitch pine can grow in poor sandy soil whereas other types of trees on Long Island usually cannot. This indicates another change in environmental conditions. Examine the sediment layer beneath the leaf litter. Is it glacial till? You will notice that the soil is very sandy, with little silt and clay mixed in. In certain areas there is also little variation in grain size-very much like you would find in a sand dune along the ocean. Sand dunes often form at the front of a glacier. The glaciers that visited here were continental sized masses of ice. The air above the ice to the north was much colder then the air above the ground in front of the glacier. Cold air is heavier then warm air. The heavy cold air would flow down the front of the glacier in strong gusty "currents" often over one hundred miles an hour, moving any sand, silt or dust in its path. The heavier sand particles would not be carried as far as silt and dust-sized particles. Instead the sand would tend to skip along the ground, sandblasting, polishing and eroding the surfaces of any rocks that they come in contact with. This sand might accumulates into dunes or dune fields scattered along the outer edge of the ice front. Dig into the substrate. Are the grain particles all of one size? That could indicate wind blown sand accumulated here.
This large sand mound is an anthill built by Allegheny Mound Ants. Do not step on the mound! All ants will bite when disturbed and eject formic acid. Allegheny Mound ants build large ant colonies in sandy soil. Their colonies can live and grow for upwards of 15 years, all under the direction of the same Queen. Ants are very important in keeping an ecological balance because they get rid of many types of rotting debris, both plant and animal, by eating it. They also benefit plantlife because they eat honeydew-producing insects such as aphids, scales and mealy bugs-insects that damage plants by sucking the juice out of them. These particular ants are very common in the Pine Barrens because of the dry sandy soil. Would you expect to find them in a garden? Why or why not?
You are now at the northern edge of the Kettle Hole trail. The deep ruts along the side of route 51 are washout cuts formed by rainwater running off of the road and into the Pine Barrens. Stop for a moment and consider all of the features that you observed along the trail. Although the trail is only a little less then a mile long, you walked over an outwash plain, a kettle hole, glacial till and a moraine. When left undisturbed, ecological systems are formed where the living components or biota adapt to the non-living elements of the environment, such as the geological setting or availability of water. Think about the predominance of different species of trees and other plant-life along different parts of the trail. Did the vegetation always indicate a change in the geological setting-even a fairly minor one? Why arent these types of natural adaptations noticeable in developed communities? When one component of a system changes, especially one as ecologically specialized as the Pine Barrens changes, the entire system changes. In the Pine Barrens, there are rare and endangered species of plants and animals that may be lost if care is not taken to preserve the natural state of the habitat.