Thuja are evergreen trees growing from 10 to 200 feet (3 to 61 metres) tall, with stringy-textured reddish-brown bark. the shoots are flat, with side shoots only in a single plane. the leaves are scale-like 1–10 mm long, except young seedlings in their first year, which have needle-like leaves. the scale leaves are arranged in alternating decussate pairs in four rows along the twigs. the male cones are small, inconspicuous, and are located at the tips of the twigs.