Walks on Weston Conservation Land
Walk 18: OGILVIE TOWN FOREST
The Ogilvie Town Forest started with the acquisition of 48 acres from the family of Beriah L. Ogilvie in 1960. Since that time an additional 10 acquisitions have brought the total area of this forest to 196 acres. The area includes vernal ponds and wetlands separated by bedrock ridges. This area tells us an interesting story.
In the lead article of the 76th Annual New England Intercollegiate Geologic Conference published in 1984, Patrick J. Barosh states, "Southeastern New England contains some of the most interesting, varied, and complex geology of all of North America." Since 1970, much of the geologic story of this region has been reinvestigated providing many interesting luncheon discussions with my colleagues who practice geology. I will attempt to relate from a layman's standpoint a simplification of these discussions.
In the late Precambrian, there was a collision between the Paleo-North American and Paleo-African plates forming a single super continent. This "collision zone" is situated in Essex, Middlesex, and Worcester counties and is the largest fault zone in the United States. The northern boundary of this fault zone runs roughly from Newburyport along Interstate 495 and then west on Route 2. The western boundary lies along the line of Interstates 190, 290, and 395 to Long Island Sound. The southern boundary of the fault zone runs very roughly from Rowley to Interstate 95 and then out the Massachusetts Turnpike (Interstate 90) to Webster.
One major fault system in this zone is named after Bloody Bluff in Lexington where a major skirmish occurred on April 19, 1775. The Bloody Bluff fault zone runs from Newburyport down to Webster where it connects to other fault systems. This fault system was active from the late Precambrian Era into the Mesozoic Era at a time when continental plates coalesced to form a super continent. The fault forms the southeastern boundary of the "collision zone". Roughly 200 million years ago, the super continent broke up with the opening up of the North Atlantic basin just east of the old "collision zone". This left a relic terrain attached to southeastern New England that was once attached to North Africa. This terrain was further modified by the Pleistocene glaciation of 3 million to 10 thousand years ago. Repeated bulldozing of the surface by glaciation stripped most the softer material off the bedrock. Haphazard redeposition of the well-mixed softer materials left a great variety of unsorted material on the surface. Since the melting of the ice, many hollows left in the topography have filled with soft sediments and peat.
The Bloody Bluff fault system is about a mile in width. Along Route 117, as one enters Lincoln, one can see wetland covering areas of shattered bedrock. The wetland is bordered on the west by a ridge of Precambrian volcanic tuff. This volcanic tuff is a very fine grained igneous rock. The individual crystals are almost invisible to the eye and it feels like a fine sandpaper. About a tenth mile further west beyond the vegetable stand across from Bowles Terrace, the protruding highly stressed Precambrian Dedham Granite is hard to recognize. West of this outcrop, a valley free of rock outcrops runs from Lincoln north to Bloody Bluff in Lexington and south along the Lincoln/Weston border. On Route 117, this swale runs west from the Dedham Granite outcrop to a rock outcrop at the east end of Massachusetts Audubon Society's Drumlin Farm in Lincoln.
PARKING: Three parking areas are available.
1) Drive up Concord Road in Weston into Lincoln where it becomes Tower Road. Make the first left turn in Lincoln. This road is Stonehedge Road and it runs along a resistant rock outcrop which is a part of the Bloody Bluff Fault system. Park just before reaching the turnaround at the end of Stonehedge Road by telephone pole number 134/20. Near this pole there is a stake marked TRAIL. If you follow this trail for about 200 feet, you will come to junction 9 in Weston.
2) There are two pull outs for parking on Sudbury Road in Weston; one just beyond 133 Sudbury next to a path entering the Town Forest; and the second just beyond 147 Sudbury Road at a gate on a fire road. Don't block the gate when you park here.
This walk requires an hour and one-half to two hours and looks at parts of the Bloody Bluff Fault system which are displayed here.
Park in the parking place just beyond 133 Sudbury Road. The area just north of the road is an old borrow pit possibly used for fill at the time the road was built. Enter the pine plantation on a path marked by an F & T arrow. The forest floor here is covered with Canada mayflower or wild lily-of-the-valley (Maianthemum canadense) and starflower (Trientalis borealis) in May. The path bears right, passes through a stone wall, then bears left leaving the pine plantation. Continue straight ahead ignoring the path to the right. Here, where more light reaches the forest floor under the hardwoods, one can find partridgeberry (Mitchella repens) which blooms in early July.
The path comes to a fire road. Take the road to your right into a mixed woodland. The road rises and soon reaches junction 8. At junction 8, follow the fire road to your left. As you follow the fire road, you will note that you are walking between two ridges. Here the bedrock outcrops are a volcanic tuff like that along Route 117. You may also note that the mid-story trees in this area include many hemlocks. The fire road soon reaches junction 5. Bear left and follow the road to junction 4. At junction 4, bear right and continue along a road. Again, as you descend along the road, you will find yourself in a hemlock grove with ridges with bedrock outcrops on either side of the road. These ridges diminish in height as the road ends at junction 3. At the left side of this junction, there is a sign which reads:
Low Impact Harvesting
The wood harvesting in this forest is being done using low impact logging techniques. These methods are an integral part of Land's Sake approach to managing forests in an ecologically sustainable manner.
METHODS OF LOW IMPACT HARVESTING:
1. Directional Felling — Trees are cut to fall in directions that minimize damage to remaining overstory and understory trees.
2. Shedding and Winching — Once the trees are felled they are limbed and bucked (cut) into lengths ranging from 4 to 16 feet. The logs are then winched or pulled and bunched into piles along temporary skid trails where they will be split into firewood or skidded to a sawmill site.
3. Slash — the branches, limbs, and tops of felled trees are called slash. These remains can be one of the most unsightly aspects of a logging job. To make the harvesting more aesthetically pleasing to recreational users, Land's Sake cuts the slash to less than two feet in height.
4. Skid trails — The skid trails coincide with the already existing trail and fire road network in this area. After the firewood has been removed the skid trails are no longer used and will regenerate with forest tree and plant species.
Through these low impact methods, Land's Sake makes it possible to harvest forest products, and to enjoy the beauty of the woods at the same time. The area to the west of this sign to the Wayland border was harvested in the winter of 1994.
At junction 3, bear left on the road which descends into a swampy area and becomes a path. Be careful as it can be difficult to follow paths in this swamp at certain times of the year. Keep right when the path splits at the edge of the swampy area and when it ends on another path. If the path is under water, then go to your left on a slightly drier path and take the first right. You are soon on drier land with evergreen, leatherleaf, or marginal woodfern (Dryopteris marginalis) and with cinnamon fern (Osmunda cinnamomea), one of the wetland marker plants in the swamp to the right. A red maple canopy is present in the swamps. A ridge soon comes into view on the left as the path rises. There is a path to the left which goes up to the top of the ridge. Just beyond this path, there is an orange sign on a tree which reads:
BEWARE WITH HORSES
Going along the path for a short distance, we reach a swamp in which we can see cinnamon fern (Osmunda cinnamomea), jewelweed or spotted touch-me-not (Impatiens capensis), sphagnum moss, and tussock sedge (Carex stricta). Hans van Leer, who once farmed near this area in Lincoln, lost a horse in this quicksand. The edge of the swamp is close to the Lincoln/Weston Town Line. In this area, the swamp fills the swale just west of the Bloody Bluff Fault system that was described earlier as being between Bowles Terrace and the east end of Drumlin Farm along Route 117.
Let's reverse our direction and return to the path by the orange sign and climb the hill. The hill is an outcrop of a resistant bedrock of the fault system. The trees are mainly black (or red) oaks. Avoid the paths leading to the left and keep along the top of the hill. The path descends along a borrow pit. This borrow pit was used as a rifle range during World War II. The path levels out and reaches a fire road near a stone wall which is on the Wayland/Weston Town Line. The meadow in Wayland is a property of the Sudbury Valley Trustees. It is a pleasant place to rest for a moment in the sun and have a snack. (Remember: take your candy wrapper and other trash back home for disposal. Respect our wild land!) Often, a broad-winged or red-tailed hawk will drift in the air above the meadow.
Return to the opening in the stone wall and follow the fire road to the east. The fire road was the southerly boundary of the van Leer Farm that extended north to Massachusetts Audubon Society's Drumlin Farm Sanctuary. The road gradually rises until it reaches junction 2. As you walk toward the junction notice that there is a ravine on your right. This ravine is one of the outlets of the glacial Lake Sudbury. By the junction, there is a sign which reads:
Wildlife Habitat Enhancement
This forest project uses sound silvicultural practices to maximize the wildlife potential of this woodlot. Increasing habitat diversity is the key to creating an area attractive to a wide array of animal species. Our work site will become a habitat "island" surrounded by more homogenous secondary growth woodland. Animals have four basic needs to sustain life.
1. Food — Forest thinning increases the available sunlight allowing the remaining trees to produce valuable food such as acorns and pine nuts. Berry bushes and tender herbaceous growth flourish with more space and light. Associated with this burst of growth is an increase in insect abundance, an important food source for many animals.
2. Cover — The forest provides sites to nest and rest and gives protection from weather and predators. New growth combined with brushy slash will offer thick ground cover. The hemlock grove has been preserved. Den and cavity trees are left standing as these provide natural holes for the use of birds and mammals.
3. Water — Logging activity has been kept out of wetland areas and our low-impact harvesting methods maintain soil integrity to prevent erosion. Therefore water quality is kept high and this is especially important for the resident amphibians.
4. Space — Wildlife needs space to support healthy populations. This fifteen acre cutting area lies within a very extensive tract of contiguous conservation land. The open character of this woodland provides an excellent opportunity for wildlife observation. Trail users may enjoy seeing a Great-crested Flycatcher with a mouth full of insects for its nestlings, catch a glimpse of white-tailed deer bounding away at dusk or even see a fox dinning on an eastern cottontail. Please report interesting wildlife sightings to Land's Sake.
Bear left from junction 2. Keep bearing right when the fire road reaches a wetland. Note the presence of our wetland indicator plant cinnamon fern (Osmunda cinnamomea) and that, at this site, it is accompanied by interrupted fern (Osmunda claytoniana). Interrupted fern is recognized by the fact that its leaves often show a pattern on the stems of green sterile leaves, deep green or brown fertile leaves, and ending with green sterile leaves. Beyond the wetland, the path becomes a road which rises to reach junction 3.
Continue straight ahead from junction 3, avoiding the road at the right. In about 60 feet you reach a junction. The path going left enters Lincoln. Paths in Lincoln are usually marked with red plastic circles or rectangles which are often accompanied by a red diamond which indicate those parts of Lincoln's Trail System closed to bicycles. Bear right keeping in Weston. The wood is drier here; bracken fern borders the path. The path rises as it passes a resistant section of volcanic tuff along the Bloody Bluff Fault. In about 170 feet, we come to a junction. Turn right along a narrow path which rises as it heads to the south. The trees are largely a mixture of pine and black (or red) oak and the understory plants are mainly members of the heath family. At the height of land, take the path to your left which goes east rather than continuing to the south. This path continues to rise for about 25 feet and then slowly descends passing through a stone wall into a pine plantation. To your right, there are wetlands. Soon, on the left, some houses in Lincoln come into view and then you reach junction 9.
Just to your left at junction 9, there is a path leading northeast. This path marked with a large No Bikes sign and with a white arrow on a red rectangle leads to the parking place on Stonehedge Road in Lincoln.
To continue on our route, bear right at junction 9. The houses in Lincoln remain in view with an occasional trail from their yards. The trail bears to the right just before reaching a vernal pool, rises over a low ridge, and then gradually descends. About 150 feet beyond the vernal pool site, there is a junction. At this junction, bear to the right. The path slowly descends and crosses an intermittent stream. These wetlands are the breeding place of several species of amphibians and invertebrates. Just beyond the stream, the trail follows an esker. An esker is a glacial deposit in the form of a winding ridge that formed from deposits of a stream that once flowed within the glacial ice. On either side of the esker, there are wetlands. Note that in this wetland area, the canopy trees include red maples and that the understory has cinnamon fern. At junction Y, avoid a path on the left going into the wetlands. Red maples disappear from the canopy when we reach drier woods.
The path reaches a fire road at junction 6. Head left (southwest) along the fire road. Note the bed rock outcrop of volcanic tuff on your right. As you continue, another fire road enters from the left and 60 feet beyond you reach junction 7. Avoid the path going to the right here, and continue going straight ahead. On the right side of the path, there are the remains of two pre-World War II vehicles. In about 150 feet beyond junction 7, turn to the right on a path leading into a pine plantation. The path rises and passes around a bedrock outcrop to your right. Bearing to the right, the path descends, crosses 10 to 15 feet of wetland. This wetland has examples of cinnamon and interrupted fern plus another wetland indicator plant, royal fern (Osmunda regalis). The path then rises into a pine plantation and reaches the path that we used to enter the forest. Turn left, pass through a stone wall and bear left along a path running straight to the Sudbury Road parking place.