Evergreen trees are most prevalent in the northerly latitudes of the northern hemisphere, where they are the primary components of the taiga, or boreal, forest and montane forest biomes. Evergreen trees are also found in the southern hemisphere and in pockets centered around the equator. In warmer climates, evergreen species can be dominant elements of tropical and temperate rain forests.
The evergreen forests in the northern hemisphere are overwhelmingly made up of coniferous species, including firs, pines, junipers and spruces. These types of species thrive in environments where summers are short and winters are long and harsh. Conifers don't have leaves, instead, they have waxy, tough needles or scale-like foliage.
In tropical and temperate rain forests, evergreen tree species aren't limited to just conifers. Warm temperatures and ample rainfall, as well as little or no winter season at all, allow other types of species to keep their leaves throughout the year. Angiosperm species located in habitats that experience winter are deciduous, dropping their leaves and going into dormancy to protect themselves from the harmful effects of freezing. Angiosperms in tropical and temperate rain forests, including palms, figs and eucalyptus, don't have these seasonal constraints and keep their leaves all year. Evergreen gymnosperms, such as cycads, are also commonplace in rain forests.