Hemlock trees are characterized by wide, linear needles with short, rounded ends. Unlike many types of evergreen trees, the hemlock's needles grow on small stems attached to twigs and are one of the tree's most distinguishing characteristics. Hemlock tree needles are green, and have two fine white lines on their under surface. The small, papery pine cones produced by the hemlock are about 3/4 inch long.
The bark of hemlock trees, ranging from medium brown to orange, is especially notable for its cork-like and heavily ridged texture. However, in young trees, the bark is much smoother. Hemlock tree bark was traditionally used for its high levels of tannin to treat animal hides.
While Eastern species of adult hemlock trees are conical and spreading in shape, the Western species of the tree has a much more narrow, conical shape, similar to a Douglas fir. Hemlocks are also notable for their thin, delicate branches that have drooping tips at the ends, making them look quite distinctive from other major types of evergreen trees such as spruce and fir trees. This evergreen tree averages a height of 60 to 100 feet tall and can have a trunk up to 4 feet in diameter.