Hemlock trees grow to a very old age - they can be up to 800 years old!
They have short needles a little over half an inch long.
The needles lie flat in two rows.
Hemlocks have small cones about an inch long.
These trees like to grow in shade.
Hemlock wood is commonly used to make railroad ties, because it holds the spikes well. Deer like to eat the needles.
The tree is threatened by an insect called the woolly adelgid. These bugs suck the sap from the tree. If they are on a tree, you can find their egg sacks on the bottom side of the needles. The egg sacks look like little puffs of cotton or wool.
The bugs were accidentally introduced into North America in 1924 from East Asia, and have been slowly killing off hemlock trees in the southern Appalachian Mountains, working their way north.
It is feared that the woolly adelgid may eventually kill off all of the beautiful hemlock trees in Massachusetts.