Category Archives: Observations

Education, Nature Study, Observations

Pine Hill Trails and Geology

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Pine Hill Park has a unique rocky landscape. You might not notice because our volunteers have done a good job at smoothing out the trails. And maybe the leaf litter obscures what is underneath. Or maybe you are one of our long-time users that have noticed some of your favorite trails becoming rockier with time. Also, as you travel on to the adjacent Redfield Trails and Carriage Trails, you may have noticed that rocky character of Pine Hill Park quickly disappears. All of this is largely because of the underlying bedrock.

Cliffside on Ledges Lane of the Redfield Trails.

 

The Cheshire Quartzite

Pine Hill Park rests upon bedrock that is called the Cheshire Quartzite, which is named for Cheshire, Massachusetts where it was originally discovered and mapped by geologists. It extends north and south near the boundary between the Green Mountains/Berkshires and Taconics. The Cheshire also has laterally equivalent layers of quartzite that extend into Canada and southern Appalachia, however these layers can have slightly different characteristics due to their history.

The Cheshire Formation got its start in life as a near-pure quartz sand that has since been buried, heated, and then squeezed by three subsequent collisions with other continents. All that heating and squeezing helped to make the beautifully smooth texture that compels you to lower your center of gravity (or land on your backside) on a wet day. It also causes the natural partings and breaks (faults and fractures) that can be seen in the quarry at the end of Crusher Road.

This bedrock formation is an approximately 1,200 foot thick layer of quartzite, which is entirely composed of smooth-grained quartz. The sand was deposited just off the coast of an ancient ocean. We know this because marine animal fossils have been found in other Vermont locations where the Cheshire is exposed at the surface. These fossils suggest an age of around 530,000,000 years or what is known as the early (lower) Cambrian Period. The fossils of this age are notable because they mark the beginning of life as we know it.

Poor Soil Production

Quartzite is one of the most resilient rocks at Earth’s surface. It is relatively immune to things like the acidity of groundwater and freeze-thaw cycles that obliterate other rocks. This is because of the very strong bond between the silicate molecules (SiO2) that make up its basic structure. Most rocks will break apart relatively easily (over long periods of time) along the bonds between their basic building block molecules. However, quartzite molecular bonds are so strong that breaks in the rock only occur through the basic quartz molecule, not along the edges where it bonds to others. This is still a difficult thing to do and is why quartzite breaks in glass-like shards (conchoidal fracturing) and sparks fly when struck with a hammer or another piece of quartzite.

The resiliency of quartzite means that it is not particularly good at producing soil. In fact, the very thin soil that you encounter on the Pine Park Park trail tread is glacial till material left over from when the last glaciation behaved like a gigantic bulldozer running across Vermont. The till varies from a sandy to silty texture with an orange color that is due to oxidation, much like rust. Inside this soil is jumbled (poorly sorted) Cheshire Quartzite boulders and pebbles with an assortment of rounded cobbles from other parts of Vermont. This helps explain why there seems to be no rhyme or reason to where and how soil deposits occur on Pine Hill. It is also interesting to note that virtually no additional soil accumulation took place on top of the Cheshire Quartzite in the past 10,000 years.

The above photo is from near the main entrance and shows a cut into glacial moraine material, which is much thicker than the till that sporadically covers most of the park. The sediment pile creates a sort of bluff overlooking the park and contains a variety of unsorted rocks of various sizes.

Similar Trail Systems

The way that quartzite breaks apart also means that it is not very good at providing the friction that keeps you upright. For comparison’s sake, the nearest trail system (and perhaps only) that is built upon similar quartzite is found on South Mountain in Michaux State Forest, Pennsylvania and extending into the South and Catoctin Mountains of Maryland. Similar poorly developed soil profiles are present, but the quartzite has course crystals that provide a little more friction and no glacial sediments are present.

Although it is coarse to the touch, the wet quartzite of South Mountain makes many of their trails impassable for bikes when the rocks are wet. This is because those trails are not built like ours in Pine Hill where mineral soil is brought onto the trail tread and large rocks are moved aside. It also means that the trails of South Mountain are expert-only because the trail tread is almost entirely rocks and boulders.

In Pine Hill the smooth crystal structure of the Cheshire Quartzite places even more limitations on friction between mountain bike tires and hiking boots. Every local mountain biker I know has taken a tumble on Lonely Rock. And I have seen several volunteers unsuccessfully test my warning about walking across wet rocks. Many times it only needs to be a humid day for you to break your arm.

A Rocky Lesson in Trail Building

The trails of Pine Hill Park have been built for the entire community with the goal of increasing access. This means that many rocks and boulders have been moved, trails are routed to avoid locations with no till, and that rigorous and unique trail building practices had to be adopted. In many places of the world more rocks on the trail is a good thing. In Pine Hill Park more rocks means building the world’s largest Slip and Slide or Wet Banana.

Without realizing it, the trail builders of Pine Hill were receiving a lesson in geology. With a little observing it is possible to see how this learning progressed from older rock-bordered trails that channelize water into ever-deepening ditches to newer out-sloped trails with rolling dips that disperse the water from large rain events. You can also take note that many of the trails are routed in such a way that seems to avoid rocks, which is the opposite of what builders in other trails systems tend to do.

The above photo is between intersections 30 and 30A. It shows an older style of trail building where rock walls were constructed (right side of trail) to hold in the trail tread against the slope (left side). This had the opposite of the intended effect where storm water would follow the same path and create even greater erosion. There are several trails in the park that have this old feature. Please consider volunteering if you would like to learn about modern trail building practices while mending these relics.

 

The Cheshire Quartzite trail tread profile disappears as it passes from Muddy and Rocky Ponds toward Proctor on the Carriage Trail. It also shows a drastic change moving toward the Redfield Trails. In fact, it is a striking coincidence that the boundary between the city-owned land of Pine Hill Park almost aligns perfectly with the bedrock boundary between the Cheshire Quartzite and the Dalton Formation. Perhaps it is not a coincidence. Maybe our ancestors noticed the difference in soil quality and divided the land as such?

Moving toward Proctor on the Redfield Trails and for a short distance past Muddy and Rocky Ponds you will find yourself on top of the Dalton Formation. The double- and single-track trail portions are relatively smooth while outcrops of rock similar to Cheshire Quartzite are visible. The Dalton Formation is a quartzite and parts of it look a lot like the Cheshire Quartzite closer to Rutland, but the rock is much older and it contains an important mineral called feldspar. This is the primary source for clay in soils around the world.

Where the Redfield Trails dip away to lower elevations of the Otter Creek Valley can also be explained by the the Ira Formation. This formation is composed of limestone and is much less resistant to weathering. For the full length of the Appalachian Mountains, limestone rocks underlie the valleys and quartz-rich rocks form the ridges and peaks. This is a persistent geologic pattern that largely controls the location of everything in our immediate surroundings.

Looking directly out from the overlook above Rocky Pond at the intersections of Shimmer, Overlook, and Stegosaurus Trails is Blueberry Hill, which is also capped by outcrops of Cheshire quartzite. In fact, several hills within the Valley of Vermont, such as nearby Cox Mountain and Bald Peak in Pittsford and Green Hill in Wallingford are also “held up” by the Cheshire Formation.

Moving toward Proctor as the Carriage Trail makes its descent off of the Dalton quartzite of Library Pass and across a short bit of the Ira limestone, is the Winooski Formation, which is a dolostone. This rock is a magnesium enriched limestone, which is easily weathered and provides a developed soil profile. In fact this can be seen in the very smooth final switchbacks of the singletrack that bring you down into town.

These lower elevations on the flanks of Pine Hill are also covered by a thicker layer of sediments from a river (aluvial), old lakes (lacustrine), and glacial moraines. The exception is where Cheshire outcrops occur along Grove Street. Some geologists hypothesize that there was an ice dam near the location of Evergreen Cemetery during the last glaciation, which is invoked to explain the extensive lake-derived clays found in the valleys.

The general point of this story is that geology explains much of what you see in terms of where trails have been located or sited, what maintenance practices are employed, and generally why we are such sticklers for details.

Please consider donating if you enjoyed this story and would like for us to continue stewarding this unique recreation resource.

References

Brace, W. F. (1953). The geology of the Rutland area, Vermont. Vermont Development Commission.

Ratcliffe, N. M., Stanley, R. S., Gale, M. H., Thompson, P. J., Walsh, G. J., Rankin, D. W., … & McHone, J. G. (2011). Bedrock geologic map of Vermont (No. 3184). US Geological Survey.

Van Hoesen, J.G., (2009). Final Report Summarizing the Surficial Geology and Hydrogeology of Rutland, Vermont, Green Mountain College.

 

Hikes, Mountain Biking, Observations, Trail Running, Trail Safety, Trail Updates, Trail Work, Uncategorized

Stegosaurus is now open 4pm

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August 15th, Stegosaurus will be closed for the day while we remove a couple of large dead oaks near Hour Glass Bridge. Please refrain from riding, hiking or trail running on Stego Wednesday. THANK YOU.

Nature Study, Observations

Winter 2018 Wild Times in Pine Hill Park

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We hope you enjoy Tom Estill’s exploration of the park in the winter time as much as we do.

Wild Times at Pine Hill Park
Winter, 2018

The official start of Winter in December of 2017 started off with bitterly cold temperatures and a forest covered in a few inches of snow.  Both Rocky and Muddy Ponds were completely covered in ice and snow. Birch seeds lying in the snow were a common site, especially at the base of adult birch trees. Many deer, rodent and carnivore tracks could be found throughout the forest, and many spots could be seen where deer and squirrels had dug through the snow to reach acorns and other food hidden beneath the snow. On a Jan. 2nd hike, the only birds I saw or heard were a hairy woodpecker, crow, and white-breasted nuthatches. I was happy to see porcupine tracks near the power lines on the Carriage Trail leading up to the rocky cliffs. The same cliffs which were the site of active porcupine dens in previous years. While sitting quietly next to the beaver den on the East side of Rocky Pond, I was treated to the sounds of groans of grunts of active beavers inside the den.

One day, during the second week of January, a warm front moved through the area bringing with it showers and temperatures high enough to melt most of the snow. During the night, the rain ended relatively abruptly followed by sub-zero temperatures which froze the water on the ground forming a layer of ice on the ground and a layer of shallow snow on top of the ice. The whole forest was covered in this ice/snow layer. Still, many gray squirrel food caches could be seen dug up in the snow/ice where squirrels were retrieving some of their food stores. On Jan. 14th, the only birds seen on my walk were a small flock of black-capped chickadees. Many rabbit, fox, deer and gray squirrel tracks could be seen.

Jan. 20th was a beautiful day with clear skies and temperatures in the low 40s. Typical winter birds seen included hairy woodpecker, tufted titmouse, pileated woodpecker, downy woodpecker, black-capped chickadee, and white-breasted nuthatch. It was also the first time this season I had seen SNOW FLEAS at the base of many trees. Always a sign to me that the worst of winter was behind us. I came across coyote and deer tracks next to each other and decided to follow them. The tracks led me to a deer carcass. The deer was only partially eaten, so I knew the coyote and other scavengers would be back to finish eating at a later time.


The first week of Feb. found 4” of snow on the ground. White-breasted nuthatch, tufted titmouse, pileated woodpecker, and golden-crowned kinglets were the only birds seen. Both the kinglet and red squirrels were seen at Muddy Pond, which is one of the few places in the park where both those species can be occasionally found. Rodent, deer, coyote and fox tracks a common sight.

On Feb. 11th, 15”of snow was on the ground. Lots of deer and squirrel tracks, and uncovered food caches could be seen throughout park, and the only birds seen were white-breasted nuthatch, crow, and a small flock of common redpoll near the trailhead parking lot. Many signs of active pileated woodpeckers around lower trails.

The third week of Feb. found the area undergoing a warming trend with temperatures reaching 70 degrees F on Feb. 21st. Consequently, many bare ground areas could be found throughout the park. Many streams had flowing water, and Rocky and Muddy Ponds, though completely covered in ice, both had a thin layer of water covering the ice. Even saw a few small midges flying about. Saw a gray squirrel sticking its head out of an old abandoned pileated woodpecker hole, a most endearing sight.

On Feb. 24th, temperatures were back in the low 40s. More and more bare ground was appearing throughout the forest, with only north-facing slopes containing any appreciable amount of snow. Cardinal and tufted-titmouse could both be heard singing. Many gray squirrels seen running throughout the forest. And small areas of open water could be seen along the edges of both beaver dens on Rocky Pond.

The first week of March found a few inches of snow on the ground dropped by a nor’easter which came through the area. Bare spots of ground could be found where that ground was exposed to lots of sunlight. Dark-eyed junco, black-capped chickadee, white-breasted nuthatch, and crow were seen. Both ponds were showing open water in spots around their perimeters.

On March 4th, an otter was seen at Muddy Pond.

3 nor’easters came through the area in March. By mid-March, cold temperatures had returned, both ponds were once again completely frozen over, and there was an average of 8” of snow on the ground. On March 18th, a few days before the official start of spring, birds seen included crow, black-capped chickadee, golden-crowned kinglet, brown creeper and white-breasted nuthatch.

Bobcat were once again photographed in the park. The exact time and location is being kept secret in order to insure their privacy and protection.

That’s it for this season summary. Please stay on the trails and enjoy your wildlife viewing and experiences at Pine Hill Park.

For more of Tom’s reports, check out this page

Nature Study, Observations

Wild Times at Pine Hill Park

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Enjoy Tom Estill’s fall report on park critter activity!

Wild Times at Pine Hill Park Fall Summary, 2017

The first day of Fall, 2017 found the forest very DRY and quiet. Acorns were falling, 2 beavers were seen swimming at Rocky Pond, a few gray tree frogs were calling, the only bird seen was a pileated woodpecker, and gray squirrels and Eastern chipmunk were busy collecting acorns.

A few days later, a near record high temp. was recorded on Sept. 23rd and the 24th. More birds were seen including pileated, hairy and red-bellied woodpeckers, numerous blue jays,

black-capped chickadees, white-breasted nuthatch, tufted titmouse, red-eyed vireo, and magnolia warbler. At Muddy Pond could be found about 2 dozen Canada geese, one osprey, a small flock of wood ducks, a belted kingfisher and painted turtles basking on a log. 2 LARGE black snakes were seen at Rocky Pond and white admiral and painted lady butterflies could be seen flying about.

At the end of Sept., I was still watering the American Chestnut seedlings on a regular basis due to the lack of any substantial rainfall. The forest was quiet, with Gray squirrels and Eastern chipmunks still actively collecting acorns.

The first week of Oct. found the forest wildlife typical for this time of year, but also some unusual sightings. There were about 200 Canada geese and a half dozen wood ducks at Muddy Pond, black-capped chickadees, blue jays and white-breasted nuthatches commonly seen, and my first wooly bear caterpillar of the season. Acorns were still falling.  And I was  surprised to see an Eastern garter snake up near Rocky Pond. Fall foliage was a bit of a disappointment this year. We had a dry, warm summer and early fall, with only one night reaching those cold temperatures which play such an important role in the fall foliage.

Mid-October found the number of falling acorns drastically reduced. A small flock of hermit thrushes and another small flock of white-throated sparrows were seen along with a larger flock of yellow-rumped warblers. They were flying through the forest ahead of the first major cold front moving into the area from the North.

The third week of October found acorns still falling, fall foliage was at its peak, but not near as impressive as years past, about 150 Canada geese were seen at Muddy Pond, and the population of forest birds was now taking on the typical numbers and species you usually find in the forest during the winter months. Once again, I was surprised to see an 8 inch garter snake on Crusher Road.

The beginning of November finally found cold temperatures descending upon the land. Fall foliage had come to an end, trees along the 3 lower Giorgetti trails had lost almost all their

leaves, robins could be seen migrating through the forest in large numbers, Canada geese were flying overhead, and tufted titmouse were now flying in small flocks, typical of what you would find in winter.

On Nov. 11th, temperatures reached the low 20s, black-capped chickadees(some of which were very curious and would fly right up to me) were flying in flocks, and a few spots along the shoreline of Rocky Pond were covered with a thin layer of ice. The whole perimeter of Muddy Pond was also covered in a thin layer of ice. I was particularly impressed with the “acorn fall” this year. Since first visiting the forest in 2012, never have I seen so many acorns on the ground. Should be a good year for deer, squirrels and chipmunks.

The last week of November found the forest covered in a thick layer of fallen leaves. Most trees have lost their leaves and only a few birds would be seen on my walks. Both ponds were covered with a thin layer of ice, with the exception of the very center of the ponds. Many trees along the shores of Rocky Pond showed recent beaver activity. It’s hard to believe the increase in size of the East side beaver den on Rocky Pond. This time last year, it was a small pile of a few small branches. Now, it’s massive.

By the second week of December, loose associations of tufted titmouse and black-capped chickadees could be found throughout the forest, and both ponds were completely covered over in a thin layer of ice. Water level at Rocky Pond is the lowest I’ve seen it for a long time.

Beaver dams are intact, so I know it’s just been the lack of precipitation which had contributed to the low level.

Finally got an appreciable snow mid-December. About 6 inches of snow on the ground, with MANY deer tracks throughout the forest. You could also find numerous piles of leaves where deer had been looking for acorns underneath the snow. Hairy woodpeckers, white-breasted nuthatches, tufted titmouse and crows flying overhead were a common sight. Both ponds completely covered with a now thickening layer of ice, with the exception of small open water areas near the west side beaver den on Rocky Pond, and the east side beaver den on Muddy Pond. Gray squirrels seen in the forest, but no chipmunks.

That’s it for this issue, please stay on the trails, and enjoy the Wild Times At Pine Hill Park.

Find more of Tom’s reports here.

Mountain Biking, Observations, Pine Hill Partnership, Trail Safety, Trail Updates, Trail Work, Uncategorized

A few trails will be closing soon

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As we are in the midst of the freeze thaw cycles. We have a few trails that we will be closing off for winter. This will happen the week of November 20th. These trails stay closed until spring is well under way.

Droopy Muffin (steep hill) between Intersections 30 and 30A will close, Lichen Rock and Exit Strategy. We do this to protect the trail tread from ruts when it’s soft and folks are riding. There is always a good possibility that Voldemort will close in late winter once the surface water starts running.

Please respect our trail closures. Our volunteer groups work really hard to have a great trail system so please don’t make work for them by rutting trails up.

Thanks! Remember rubberside down.