Cedar species in the United States can cause confusion to the uninitiated, as some common trees referred to as cedars aren't, such as the eastern red cedar which is really a member of the juniper family. The true cedars consist of species such as the Atlantic white cedar, Alaska cedar, northern white cedar and western red cedar. These trees all have some features in common that you may look for when trying to identify one as a cedar.
Take note of the aroma of the bark, scales and branches. The familiar smell that you get from opening a cedar chest permeates a living cedar tree as well. Any twig or small branch you find broken off will contain this pleasing scent.
Peel away the fibrous bark of a cedar tree to discern it from other species. The bark will easily come off in thin, stringy strips. Notice the ridges under the top layers of bark.
Note that a cedar is an evergreen tree. It does not have leaves like a deciduous tree or needles like the pines. Instead, a cedar tree has flattened branchlet networks covered with scales that are some shade of green.
Use the height of the tree to identify what type of cedar it may be. Northern white cedar grows to heights of 50 feet but some of the cedars of the far West grow much taller. The western cedar is a massive tree, with a trunk as wide as 8 feet and attaining heights up to 200 feet. The Alaska cedar grows to 100 feet commonly while the incense cedar can make it to 150 feet.
Familiarize yourself with where cedar trees grow in the United States. The eastern species are the northern white cedar of the Northeast and the Atlantic white cedar, which is a native species of the coastal area along the eastern seaboard. The incense cedar grows along the Pacific Coast; the Alaska cedar growsnsouthward from the southern Alaska coast into British Columbia and parts of Washington State; and the western cedar grows in the Pacific Northwest.
Identify a cedar by the small size of its cones. The different types have cones of various shapes but all are less than an inch long, except for the 1.5-inch long cones of incense cedar.