The Harvard Forest is a collection of five properties, totaling about 1500 hectares, in Petersham, Massachusetts. Petersham is a rural town in Worcester County, Massachusetts,
about 60 miles west of Boston. It is largely in the Swift River Watershed, and lies near the center of a twenty-mile wide band of hilly uplands that form the eastern edge of the Connecticut Valley. The north part of the town is rolling and the south more distinctly hilly; the lowest basins are about 200 m above sea level, the flats around 400m. Th e climate is cool temperate. Petersham, like many of the adjacent towns, was settled in the early 18th century, extensively cleared and farmed in the next hundred years, and then progressively abandoned after about 1830. Reforestation proceeded quickly, and by the time of the first Harvard Forest maps in 1909 HF was almost entirely wooded. Th e common forest types are dominated, variously, by red oak, red maple, white pine, or hemlock. Most are of low or average fertility and under 100 years old. Hemlock is now locally dominant in many stands that have been continuously forested; oaks, red maples and pines are the common dominants in stands that developed in old fields.