A conifer is any plant belonging to the class Coniferinae. Both trees and shrubs fall into this group, though the majority of conifers are trees. Coniferous trees are most easily identified by the cones that they bear.
A conifer tree must bear its seeds in one of two ways. The seed is either borne in a cone, which has small scales that open up to disperse the seeds, or as a single drupelike seed. These singular seeds are most often borne as yews. Those trees that do not bear their seeds in cones will still bear the pollen in cones.
A conifer tree typically has very distinctive foliage. This foliage is extremely narrow and pointed. Pine needles are a classic example of the type of foliage found on conifers, though some have slightly thicker and wider leaves. A few varieties have leaves with small scales along their length while others have leaves with more of an awl shape.
Most conifers have green leaves year round. For this reason, they are often referred to as evergreen trees. Though the leaves of the conifer tree do fall off, they do so gradually over the course of the year and are regularly replaced with new, young leaves. Thus, a conifer tree appears to keep its foliage throughout the year.
Many forests are composed almost entirely of these types of trees. Coniferous forests can be found in the United States, Canada, Europe, and Asia. These forests grow in areas with clearly defined seasons. They require both a long winter with plenty of snow, and a warmer summer with some humidity. At least one third to one half of the year must be frost-free for optimal growth and health.
Coniferous forests are well suited to significantly less rainfall than other types of forests. The slender shape of the needles on conifer trees help them to conserve water. Foliage with this shape allows for less evaporation. The waxy coating on the surface of the leaves also serves to retain water.
Well known examples of the conifer tree include cedar, fir, redwood, pine, juniper, and spruce. More specific examples can be found in the balsam fir, red pine, white spruce, eastern hemlock, and white cedar. The popular Christmas tree displayed throughout the holiday season in many homes is a classic example of a coniferous tree.