A tropical rain forest is really three different worlds—stacked one on top of another. The first layer is the dim forest floor. The thick vegetation above lets in very little light.
There is also very little wind. Even during the most violent rainstorms, the leafy upper branches of trees reduce the wind, so the floor remains calm. Because there is so little light, few plants grow on the forest floor. Except for tree trunks, the floor is relatively open.
The second layer of the forest is the understory, which is also dim and humid. It’s full of bushes, shrubs, vines, and small trees. Some of the trees will eventually grow taller and become part of the third layer.
The tops of very tall trees in the forest form the third layer, the canopy. Canopy trees may reach a height of 150 feet. Slender trunks branch out into leafy crowns, forever reaching for sunlight. Some canopy trees, stretching to get above the crowd, may grow to 200 feet. These are known as emergents.