Heritage Sawmill Park is a hidden wonder in Leverett, Massachusetts. The park is filled with an abundance of wildlife species and home to an amazing variety of trees and shrubs as well as a rich history of human habitation. This little sanctuary along the Sawmill River is a great place for a quiet walk, to go birding, wildlife tracking or to marvel at the incredible stonework. During my first few visits to the Park I experienced some amazing wildlife encounters from watching deer soak in the river on a hot day while the Phoebes eat deer flies off their backs to watching Northern Water Thrushes bob back and forth and feed their young chicks, to watching Black Throated Green Warblers feed and build their nest. The Sawmill Park also has some remarkable stonework from the dam at the sawmill, down the levee to the Iron works. The amount of labor and craftsmanship that went into these stone monuments make this place an extraordinary destination and historical landmark that holds many old stories and ongoing mysteries. See below the bird and animal species I was able to identify in the park on my visits. This is not comprehensive but gives an idea of the diversity that lives there.

Written by certified wildlife tracker Neill Bovaird of Wolf Tree Programs, Montague, MA (pictured on the sign), who provided much of the material for this section.

Forest Communities and Threats

The area that encompasses the Heritage Park and Nature Trail is composed of northern hardwood trees. This includes the coniferous species of hemlock and white pines along with long-lived deciduous trees and sparse shrub and herbaceous plant underlayers. This type of land has a moderate level of nutrients and retains moisture with its shallow leaf litter layer. A listing of the trees in the park is found on Informational Sign #7. The understory shrubs include leatherwood and mountain laurel, and the occasional herbaceous plants include trilliums, wood and Christmas ferns and clubmosses.

Threats to native forest and plant habitats include invasive plant, tree and shrub species that may be more aggressive and thus more successful than some native plants as well as pests that damage or kill them. Several invasive species are found in the park including Oriental bittersweet vine, buckthorn trees, multiflora rose, honeysuckle bushes, Japanese knotweed, garlic mustard and vinca minor (a garden escape). A program to control or eliminate some of these has been implemented. To that effect, you will see the remnants or stumps of shrubs and trees that have black plastic bags known as “buckthorn bags” wrapped over them. These bags are designed to prevent regrowth of the invasive species in the absence of herbicides and without removing the roots of the plant which may be important to prevent soil erosion on hillsides and wetlands such as those found in parts of the park. These invasives are being replaced by native trees and shrubs that are adapted to the park environment and which must be protected from deer damage while they are young. Also, native perennial plants have been introduced in the Habitat Garden areas and some of these may spread within the park. These are expected to enrich the health of the park by encouraging insect and bird life.

Information for this narrative was provided by Eric Donnelly of Woodsmith Forestry, Montague, MA, who is a certified arborist and expert on invasive shrubs and trees.

Pests that threaten trees in the park include Asian long horned beetle, Emerald ash borer, beech leaf disease caused by a nematode Litylenchus crenatae mccannii and beech bark disease caused by a scale insect and a fungus. The latter results in cankers on the tree bark as well as cracked bark. Unfortunately, this is prevalent on the beech trees in the park.

The Heritage Park Floodplain

Much of the area adjacent to the Sawmill River in the Park is a unique type of land known as a floodplain. This means that the land stretching from the riverbank to the area of higher ground tends to flood when there are heavy rains and high river flows from snowmelt or because of ice jams. In this instance of the Heritage Park, the higher ground is the berm that reaches up to North Leverett Road. But because the stone and earthen embankment was built to divert the river to the Ironworks containing it in a canal, it also means that the expanse of area that can flood is reduced. These kinds of landscape changes (building berms, levees, and straightening the course of the waterway) has led to a major reduction in active floodplain areas throughout the New England region.

Small regular flooding is essential to a river’s health benefitting wildlife, fish, plants and people in a more general sense. Floodplains act as a natural filter by absorbing harmful chemicals and other pollutants, recharging ground water supply. By temporarily slowing and storing floodwaters, they also can help reduce downstream flood damage to roads and residences. The flooding also fosters a distinct assemblage of native trees and other plants adapted to these special conditions and creates seasonal wetlands that serve as habitats for fish, amphibians and reptiles. Flooding is also needed for some fish and plants to complete the reproductive cycles.

Flooding can flush out invasive plants and animals thus benefitting native species. However, this is not effective for all types of plants. You will see small clumps of Japanese knotweed plants along the edges of the river in the shallows if you look closely. The presence of knotweed which is encroaching into the park from the west end will reduce the floodplain habitats and is an important concern.