True hemlocks are tall, coniferous trees that exhibit short, blunted leaves and slender branches. The branches, which may be horizontal to the ground or drooping, are generally covered in reddish to purplish brown bark and are tipped with small, egg-shaped cones that hang downwards. Native to North America and Asia, some hemlock species have been greatly reduced in number due to human development. For instance, the common hemlock of eastern North America, scientifically described as T. canadensis, has been commercially valuable as a source of tannin and a type of tea may be made from its young needles, but the tree is not as prevalent as it once was.