One fact about forests is that they occupy approximately one-third of Earth's land area. Forests are complex ecosystems where many different types of plant and animal species coexist. While there are different types of forest, trees are typically the dominate species of such ecosystems. Forests provide a number of important ecological functions that include water filtration and the regulation of atmospheric carbon dioxide.
Forests have three different layers: the forest floor, the canopy and the understory. Forest floors are home to many different types of animals and plants such as grasses and wildflowers. The floor itself consists of soil as well as the decomposing biomass created by dead plants and animals. The understory, also known as the shrub layer, contains small trees, bushes and shrubs. The leaves and branches of the trees make up the canopy, which is the tallest layer of the forest.
Tropical rain forests grow near and around the equator. These forests have the greatest species diversity of any biome. Temperate deciduous forests have four distinct seasons and are home to many different species of mosses, ferns and wildflowers. Temperate coniferous forests are found in many coastal areas that have mild winters and heavy rainfall such as the Pacific northwestern United States, southern Japan and parts of northwestern Europe.