Characteristics of Plants That Survive in a Rainforest

Rainforests are made up of several layers of vegetation, each representing a distinctly different habitat and requiring special adaptations by the plants that survive there. Some tropical rainforest plants have special leaves to collect as much of the sun that filters through the canopy as possible; others climb trees to push their leaves toward the sun. Roots have adapted to support trees of enormous height or reach from the treetops to the ground.

Trees 100 to 250 feet tall, like the kapok (​Ceiba pentandra​), hardy in U.S. Department of Agriculture plant hardiness zones 10 through 12, stand above the all other trees in the forest and make up the emergent layer. The tree tops are in full sun and subjected to the full force of winds. Their leaves are usually small and adapted to retain moisture. Ordinary roots could not support trees of this height, so large buttresses up to 30 feet long brace the tree.

Tropical epiphytes like members of the orchid family (Orchidaceae), hardy in USDA zones 10 through 12, attach to the branches of emergent trees where they can obtain sunlight. Their roots, called adventitious roots, enter the bark or rest on the bark to obtain nutrients and water where they collect. They are usually able to store water to survive periods of drought.

Trees 60 to 100 feet tall make up the canopy layer of a rainforest. This layer is in full to partial sun and protected from winds by its density. Trees of the canopy are densely packed, forming a protected environment with full and partial sun. Fruiting trees and vines are part of the canopy layer, including figs (Ficus spp.), hardy in USDA zones 9 through 12.

Lianas are a variety of woody climbing vines, members of several different tropical species. Growing up to 3,000 feet long with sucker roots, they wrap around the trees of the canopy in an effort to reach the sun. The woody stems are so dense that they provide extra support for the shallow-rooted trees.

Other plants in the rainforest, like the tree philodendron (​Philodendron bipinnatifidum​), hardy in USDA zones 9 through 11, start growing high in the treetops and send roots down to the ground. A tree philodendron may grow up to 15 feet tall in its native habitat. Its roots can grow over 90 feet long.

Trees and other plants less than 50 feet tall make up the understory of the forest. This layer gets little sunlight and is very humid. The plants growing in this layer of the forest have leaves up to 8 feet long to collect as much of the filtered sunlight as possible. The leaves have some adaptation to shed water, usually glossy leaves that repel water. and/or pore-like structures called stomata.

Flowering plants, such as the ​Heliconia​ species, hardy in USDA zones 10 through 11, produce tiny flowers within large, brightly colored bracts. These tropical plants range in size from 18 inches to 15 feet tall. Other flowering rainforest plants feature strong scents to attract pollinators. Sapling trees also inhabit the understory and are adapted to grow rapidly toward the sunlight.