Layers of the Rainforest Quiz
Four layers, top to bottom
A tropical rainforest is stacked in layers, like floors in a building. At the top is the emergent layer: a few giant trees that poke out above the rest, sometimes 60 m tall or more, in full sun and wind. Eagles nest up here.
Below them is the canopy, a thick roof of leaves and branches about 30 to 45 m up. It catches most of the sunlight and the rain.
Under the canopy is the understory, a dim, warm, still world of shrubs, young trees and big leaves. At the bottom is the forest floor, so dark that only about 2% of the sunlight reaches it.
Life in the canopy
Most rainforest animals live in the canopy, where the food is: fruit, flowers, leaves and insects. Monkeys, sloths, toucans, tree frogs and countless insects may spend their whole lives up there.
Many plants grow on the branches instead of in the soil. These epiphytes, like orchids and bromeliads, get water from rain and air. Rainwater collects in the cup-shaped leaves of bromeliads, making tiny ponds where some frogs raise their tadpoles.
The canopy is so hard to reach that scientists use climbing ropes, tall cranes and walkways strung between trees to study it.
Why rainforests matter
Tropical rainforests cover only about 6% of Earth's land, yet they're home to more than half of all the kinds of land animals and plants. The Amazon is the largest.
They get a lot of rain, usually more than 2,000 mm a year, and they help make it: trees pull up water and breathe it out through their leaves, forming clouds.
Surprisingly, rainforest soil is thin and poor. Fallen leaves rot fast on the warm forest floor, and the nutrients are quickly taken back up by plants. When forest is cleared, the soil soon wears out.