A tropical rainforest is a humid environment that has year-round warmth. Mostly found near the equator, rainforests are in South America, Africa, Southeast Asia and Indonesia. The largest tropical rainforest in the world is the Amazon rainforest, which covers more than half of Brazil. The Amazon rainforest is made up for four layers, each with distinct plants and ecosystems.
The emergent layer is the uppermost layer of the rainforest. Trees in this top layer grow as tall as 240 feet high and are exposed to variations in temperatures, winds and rainfall. These trees have small leaves covered with a waxy thick surface for holding water. The kapok tree is an example of a tree living in the emergent layer.
The canopy is the primary layer of a rainforest. About 70 percent to 90 percent of plant life in this layer is trees, according to the Unique South American Travel Experience website. Usually canopy trees have smooth leaves coming to a point called a drip tip, which lets water flow off a leaf quickly, preventing fungi, mosses and lichens from growing. Through the process of photosynthesis in which sunlight is converted into energy, leaves provide the forest with the ability to make food for plants. Trees in the canopy layer are dense and are able to filter out 80 percent of the sunlight, according to BluePlanetBiomes.org.
Plants of the Canopy Layer
Although the canopy layer has the highest amount of seeds, fruits and flowers, its ground vegetation is minimal, consisting of mostly vines and tree seedlings. Plants that grow on canopy trees (epiphytes) are well adapted to their aerial environment and develop different ways to obtain nutrients from their surroundings. The liana, which is a woody vine beginning as a shrub on the forest floor, is another plant type that’s typical of the canopy layer. As it grows it makes its way up to the canopy layer by latching onto canopy trees. Another canopy plant type, the hemiepiphyte, starts life in the canopy, growing long roots that can eventually reach the forest floor.
According to BluePlanetBiomes.org, the understory layer only receives about 2 percent to 15 percent of the sunlight. Because not much sunshine reaches the understory layer, plants need to grow larger leaves. The understory layer contains orchids, lichens and ferns. These plants typically grow more than 12 feet high. Because there’s not much air movement, they depend on insects and animals for pollinating their flowers. More insects live in this layer than the other levels.
Forest Floor Layer
The forest floor, which is the lowest and darkest layer, receives 2 percent of sunlight, so barely any plants grow there. This layer is littered with decomposing vegetation and organisms that are broken into nutrients. Although there’s not much plant life, the largest forest animals live here.