A tropical rainforest is made up of six layers: emergent tree, canopy tree, lower tree, shrub, field and ground or floor.

Lower tree, shrub and field are known collectively as the understory.

The emergent layer is composed of trees that grow much higher than the other trees.

Below this layer is the main canopy, which is composed of flat-crowned trees. Together with the emergents, they make up a complete canopy.

Beneath the main canopy are smaller trees, often with vertically elongated crowns. These constitute the lower tree layer.

In reality, there is almost continuous greenery extending from the top of the canopy to the bottom of the understory, with sparser foliage between the understory and the ground.

It is not easy to see where one layer of forest ends and one begins.

The margins of roads, rivers and clearings quickly acquire a lush growth of climbers that obscure the normal structure of the tropical rainforest. Within the rainforest, the layers are linked by the stems and foliage of lianas; these are generally omitted from profile

The layered structure of the tropical rainforest is the key to its fantastic richness, because the layers provide innumerable tiny and discrete habitats.

The complex, layered framework of trees engenders complexity in the animals and plants that depend on them.