The document describes the four strata, or layers, of a rainforest: 1. The canopy is the top layer up to 40 meters high and forms an umbrella over the forest. 2. The emergent layer is above the canopy up to 60 meters and contains the tallest trees. 3. The understory below the canopy is dark and varied with trees up to 20 meters. 4. The forest floor contains few nutrients and river life. It also lists products derived from rainforests such as foods, medicines, and wood.