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Grater Woods Town Forest

At the end of 2008, the Grater Woods Town Forest was a 480 acre parcel of land. It was formed through land acquisitions by the Merrimack Conservation Commission and is composed of several parcels. The Merrimack Middle School sits on a 32 acre of easement-protected open space. Although the school parcel is administered by the Merrimack  School District, the open space land on each parcel is managed in accordance with open space guidelines set forth by the MCC.


The land was cleared for pasture in previous centuries, has been logged several times, and now consists primarily of a mixed hardwood forest with trees between 20-60 years of age. The property includes a series of streams, ponds, swamps and numerous wetlands totaling approximately 100 acres.

Logging roads form the basis of what is today a trail network used by hikers, bikers, hunters, snowmobilers, horse back riders, skiers, ATVers and bird watchers. This trail network does cover the majority of the property.


The varied terrain, habitat, and large areas of undisturbed open space have encouraged a wide variety of wildlife to thrive on the property. This varied area served as an important habitat for wildlife as well as providing recreational benefits to town residents. Contained within this parcel are habitats for beaver, fisher, deer, moose and turkey as well as unique areas such as vernal pools, beaver ponds and glacial erratics. The parcel, together with other forests in the region, provide a wildlife corridor (greenway) that allows animals to freely migrate in and out of the forest.


Due to its size, quantity of wetlands, and impact on wildlife and water resources, this property was listed as a top priority for conservation in the 2002 Town of Merrimack Master Plan. The town forest can be identified by white rectangular boundary markers. The markers point in to the town land.


Geology of Grater Woods


Information in this section was taken from the Buker Plan.

Permission to use it was granted by the Grater Woods Sub-Committee.


On average, approximately 43 inches of rain (or the equivalent in snow) falls on the Grater Woods Town Forest (GWTF) each year. Some water evaporates, some runs off via streams and brooks, and the remainder soaks into the ground. The ponds, wetlands, streams and ground water are a valuable resource within the GWTF.



Almost all of the GWTF is located over bedrock, which is covered by a thin layer of surface till. Surface till is a mixture of glacial sediments composed of boulders, gravel, sand, silt and clay. Where the bedrock is substantially cracked or fractured, water seeps through the surface till, travels, and accumulates in the fractures creating a bedrock aquifer.


Human activity on the property impacts the volume and quality of the ground water. Gasoline and oil from spills, fertilizers, pesticides and other chemicals introduced by people can seep into the ground and ground water as contaminants. Contaminants that infiltrate the fractures in the bedrock can affect the purity of the water.


The GWTF is located within a geological transition zone that extends from northeastern Conn. to southeastern Maine. The location of the GWTF within this transition zone accounts for its varied and dramatic topography. This transition zone consists of younger metamorphic rocks (formed 420 to 425 million years ago) at the eastern portion of the property, known as the Massabesic Gneiss Complex, and the older igneous rocks (formed 620 million years ago) in the central and western part of the property, known as the Berwick Formation. The structure of the bedrock found in this transition zone is the result of an interlayering process between the metamorphic and igneous rocks, and is composed of calcareous granofels, biotite schists, and granite sills that are exposed at the surface and exist at depths of less than 25 feet.


There are 18 different soil types on the property. The most significant characteristics of these soil types pertain to their water handling capability, their slope, and their rockiness.


Large outcroppings of glacial erratics are found on both school and town property at the GWTF. They are reminders that southern New Hampshire was once covered by an ice sheet 10,000 years ago.
Updated 2/14/2010