Evergreen trees differ from deciduous trees in that they retain their foliage throughout the year. Deciduous species shed their leaves, a mechanism that helps them go dormant and survive colder weather. The evergreen does not. The vast majority of evergreen trees in North America are conifers, such as pines, firs, spruces and junipers. To identify one from another, you must consider many aspects of the tree.
Look for the needles of evergreen pine trees in bundles known as fascicles. These bundles will contain from one to six needles that hold together at their bases, depending on the specific species. Pine needles tend to be much longer than the needles of most other evergreens. Pinecones vary in length and composition, with some much more compact than others are. The bark of pine trees is typically rough and scaly. Pines usually exist in acidic soil.
Examine the shape, needles and cones of the various types of fir trees. The flattened needles will grow right out of the branches and usually possess a narrow silvery line on them, according to "Trees of North America." Fir trees are tall, thin and conical shaped,and have a spire-like crown. The cones are normally abundant in the top portions of the tree and will grow in an upright manner on the branches. Upon reaching maturity, the cones of the evergreen firs fall apart.
Study the cones of the seven kinds of spruces to discern these trees from other evergreens. The spruces all grow in cool climates of mountainous terrain or in the northern United States and Canada. Spruces have thin, light cones with woody scales. The cones hang down from the undersides of the branches. The needles of the spruces are rigid and protrude from a peg-like base on the twigs. Spruces prefer moist soil in which to grow.
Inspect the needles of the four kinds of hemlocks growing in North America, looking for a very short stem. The needles are flat, soft and give the hemlock a feathery appearance. Observe the cones and you will notice that they hang from the tips of the branches and are light, with an oblong shape. The very tip of the hemlock tree usually droops down a bit to one side.
Observe the great size of some of the other evergreen species in the United States. The redwood and giant sequoia can reach heights in the neighborhood of 300 feet and both types exist only in certain ecosystems in California and the Pacific Northwest. The Douglas fir, which is not one of the true fir trees, has a much wider range and grows to as tall as 300 feet, with most in the range of 80 to 200 feet tall. The cones of the Douglas fir have bracts, small scale-like extensions.
Look for scaly foliage and different kinds of cones on the junipers, cypresses and cedars. The cedars and cypresses have small woody cones, with some rounded and others oblong. The cones of the juniper evergreens look like berries. The foliage of these types of trees looks like overlapping scales covering their small branchlets, with the branchlets of cedars being flat, but those on the cypresses and junipers being more rounded.