Tropical rainforests form a lush, green band around the equator between the two latitudinal lines of the tropics of Cancer and Capricorn. While covering less than 6 percent of Earth's surface, rainforests are home to more than 50 percent of the world's plant and animal species. A tropical rainforest gets more than 60 inches (1.5 meters) of rain per year, although some regularly get more than 200 inches (5 meters)! For comparison, San Diego gets around 9 inches (23 centimeters) per year.

In temperate forests there is enough rainfall to allow trees, shrubs, flowers, ferns, and mosses to flourish, while also following the rhythm of the seasons: sun and warm temperatures in the summer, and snow and cold temperatures in the winter. Most temperate forests are made up of a mix of deciduous trees like oak, beech, maple, ash, hazel, and birch, along with some evergreens and conifers like pine, redwood, hemlock, and cedar.

Scrublands are areas that are dry and hot during the summer but saved from becoming deserts by cool, moist winters. Scrublands go by many names: chaparral in California, mallee in Australia, fynbos in South Africa, and mattoral in Chile.

In these areas, some plants may lie dormant during summer, budding and blooming in autumn and flourishing with the rainfall during winter. Some trees grow here, such as oaks, pines, and cypresses, but they rarely get very large.

The open spaces of the world’s savannas are found mostly in the tropical areas of the globe. The word savanna comes from the 16th-century word zavanna, which means “treeless plain.” However, the term is used to describe a more varied habitat, made up of large expanses of grasses, often one or two types that create a continuous carpet, interrupted by scattered shrubs and trees.