Town Forests make up a significant part of the Bay Circuit Trail. I've been poring through web searches trying to get a sense of their history and origins here as they appear to be a fairly unique thing.
My best guess is that they are the essence of the Commonwealth design in a time when wood was a core element of the colonial culture as a material and as a fuel. Towns set these tracts aside to provide fuel in winter for town facilities and to provide lumber for town building projects.
Eventually, other fuels replaced wood and lumbering operations were scaled up to the point where dimension stock market lumber was a better value than milling your own. The things entered a long phase of benign neglect until recently revived as the principle open space property a town is likely to have.
Despite this, they are still mysterious as there isn't any directory of them such as you would find for Commonwealth DCR properties, Federal things like National Wildlife Refuges or the many privately owned properties such as Audubon Sanctuaries or Trustees Reservations.
They are great basic living summations of their respective locations.
Veterans Commemorative Forest in Pembroke lies just on the back side of the moraine that edges the outwash plain sand lands that roll off to the south and Long Island Sound. It has some of the more extensive esker systems in the area along the northeast basin edge of Silver Lake.
Sampson Park in Kingston is on the outwash side of it all resting in moist bottom lands along the Jones River.
Further west, the Walpole Town Forest has ancient mill remnants dating back to the mid 1600s and it rests in the Neponset River basin headwaters.
Ashland Town Forest is laudably extensive and the trails are immaculate and well blazed. It is part of the Sudbury River watershed along with the Hapgood Wright Forest In Concord.
This last wonder was a a shelter for a freed slave and a favored strolling place for Thoreau and Emerson and is an outstanding alternative to Walden Pond when it gets mobbed.
Town forests are generally welcoming to many activities including dog walking and bicycling.