In Massachusetts only one type of hemlock tree grows - the Eastern Hemlock, or Tsuga canadensis. This is an evergreen tree, meaning its needles do not all fall off at once in the fall. It has short, thick little green needles.
You can see hemlock trees for yourself at Purgatory Chasm. Go to the ranger station, and there's a number of them around the picnic area.
The trunk of the Eastern Hemlock is fairly thick and woody with a medium rough bark.
The seed of the Eastern Hemlock is a small brown cone, sort of shaped like a pine cone, but more tightly wrapped.
Trees of Sutton Massachusetts
Massachusetts Foliage Photo Collection
Sutton Massachusetts Photo Album