Pine needles and yellow birch leaves wafted to the ground as the 10 or so people about to explore Horse Meadows Knoll met with Sudbury Valley Trustees guide Kristen O’Brien, Friday, Oct. 4.
Horse Meadows Knoll is a parcel of conservation land in Harvard on Sherry Road acquired in 2017 by Harvard Conservation Trust in collaboration with Sudbury Valley Trustees as part of its High Ridge Initiative, a landscape wide initiative. O’Brien described a landscape wide initiative as one that seeks to restore nature’s resilience to climate change, to reverse landscape fragmentation, and to establish connectivity to other conservation areas with sensitive ecological features.
When we gathered in the spacious parking lot, a question prompted a discussion about the definition of a knoll but did not end in a clear definition. We all agreed it was a hill, at least. In fact this knoll rises 140 feet from the road and is drumlin-shaped, that is, a separate and distinct mound.
It was a delightful day to be walking in the woods and as we walked, our guide stopped periodically to point out features that make Horse Meadows Knoll special.
O’Brien drew our attention to the almost car-sized boulders. They are glacial erratics, boulders which ordinarily would not be there except for having dropped out of the melting glacier that had collected them from afar and carried them southward.
Further on we stopped at Horse Meadows Reservoir, a naturalized pond, indicating that human intervention may have been part of the pond’s history, perhaps part of its agricultural past or efforts to protect the waters of Elizabeth Brook that run through it. There is a large, dilapidated beaver lodge in the center of the pond. It is not known if the beavers are still working in the area or have moved on. O’Brien noted that a long time ago beaver dams created meadows and fields for grazing or planting and left dead wood as the water receded. O’Brien said a healthy forest needs dead wood. Here, the still standing dead trees have provided structures for the nests of great blue herons. Beavers are considered a keystone species, which is a species on which other species in an ecosystem largely depend, such that if it were removed, the ecosystem would change drastically.
Continuing on the trail, we looked at pools and noted that there are both certified and potential vernal pools at Horse Meadows Knoll. A certified pool is protected by the Massachusetts Endangered Species Act. A potential vernal pool is one that meets certain measurements of a depression in the bedrock but all the qualities of a certified vernal pool may not have been observed. Vernal pools are important to amphibians such as the blue spotted salamander seen on the property. The amphibians need shallow pools that have grasses and vegetation for laying their eggs but do not have fish, which would eat the eggs. These species spend part of their lives in water before moving out of the pool to uplands.
Evidence of past farming
After a steep uphill section of the trail, O’Brien pointed out that Horse Meadows Knoll is crisscrossed by stone walls, evidence of its agricultural past when land was clear-cut to create fields and meadows. Therefore it is a secondary growth forest, consisting of a majority of similarly sized white pine and birch trees, the first in the succession of trees to return to a cleared area. To one observer, there appeared to be plenty of oaks and maples, and even a witch hazel, as well as pines and birches, but O’Brien said that having even 20 species of trees does not demonstrate diversity. She noted the lack of diverse seedlings and saplings in the understory. These young plants grow slowly while they develop deep and wide root systems, awaiting an opening in the canopy that would allow them the space and sun needed for their growth.
Deer browsing has an impact
Birds are affected by a lack of lower level trees and shrubs, which they need for nesting and protection, though a scarlet tanager has been observed in this forest. She stated that a line of sight in a deep, dense, diverse forest goes no farther than 10 feet, while a view through this part of the forest, its floor covered with pine needles, was extensive. O’Brien attributed the sparse number of seedlings and saplings to the browsing habits of deer. She said that Sudbury Valley Trustees is involved with a forest health initiative that has experimented with timbering and fire in its forest management. They also have a deer management program which involves bow hunting in a few areas.
At the height of land, we were at an area where safety and reparation to a natural state necessitated the removal of an abandoned house on the property. It is here that some invasive plants can be found, but they will be removed or contained. (Some phragmites in the wetlands have already been removed.) There is little evidence of the house now, and grasses cover the foundation area.
Following the old driveway, a short but steep and rocky downhill section of trail brought the group back to the parking lot.
What was great about this walk in the woods was observing nature’s resilience, its ability to repair fragmentation, and its connection to other landscape features. The beauty of a walk through the woods is engaging with the natural world on global, local, and personal levels.
