Tropical rainforests are found at elevations below 3,000 feet (http://www.radford.edu/~swoodwar/CLASSES/GEOG235/biomes/
rainforest/rainfrst.html). The vertical layers of vegetation have five subdivisions: the overstory, canopy, understory, shrub layer, and ground level. 100-130 feet above the floor is the canopy made up of a thick covering of leaves and tree branches from closely packed trees. 130 feet and higher is the area called the overstory. Directly below the canopy is the understory made up of leaves and branches. Shrubs and tree saplings 5-20 feet above the ground make up the shrub layer. The canopy contains 90 percent of rainforest species, thus housing 45 percent of biotic organisms in the world. The ground level consists of tree seedlings and vines due to the lack of sunlight that is screened from the canopy (http://rainforests.mongabay.com/0202.htm).
The rainforest canopy. Image by R. Butler
Created by Abigail H.