Tsuga heterophylla, commonly known as Western hemlock, is a large evergreen coniferous tree that can grow up to 70 m (230 ft) tall and 4 m (13 ft) in diameter. It has a narrow, conical crown and a drooping top. The bark is brown to reddish-brown, thick, and furrowed. The needles are short (0.8-2.0 cm or 0.3-0.8 in), flat, and have two white stripes on the underside.