Five Layers of a Rainforest

Rainforests contain an amazing level of biodiversity, but unfortunately they are being cut down at an alarming rate worldwide. Once estimated to cover 14 percent of Earth's land surface, rainforests now cover 6 percent. Scientists fear that unless this course is reversed, rainforests could be almost completely cleared within the next 40 years. Understanding the biodiversity found among the five distinct layers of the rainforest hopefully helps to build a greater appreciation of it.

Emergent Layer

• The highest layer of the rainforest, the emergent, is compose of the largest trees, ranging from 100 to 240 feet tall. They grow far apart and develop a shallow root system that extends out about 30 feet to support their height. Some of these trees get up to 50 feet in circumference. Their leaves are small, pointed and waxy, offering them protection from sunlight and drying winds. This layer offers habitat to many species, including monkeys, eagles and snakes.

Canopy

• This layer is much denser, with trees averaging 60 to 130 feet in height and spaced more closely together. Leaves are much larger on these trees, so light is abundant at the top of this layer, but very limited on the underside. The majority of rainforest animals make this layer their home and rarely go down to the forest floor, instead traveling from tree to tree. These include the very colorful toucans and parrots.

Under Canopy

• Little sunlight makes it to this layer -- an estimated 5 percent, and consequently this is the moistest layer with very high humidity. Even so, this is the layer where the majority of the rainforest's flora is found, much of it with huge leaves to absorb what sunshine is present. Trees, however, grow to only about 60 feet tall.

Shrub Layer

• This layer is home to small shrubs, bushes, ferns and other larger plants. Most of the medicinal rainforest plants are harvested at this level. Density of growth in this layer is determined by how much sunlight makes it through the upper layers. This can range between 3 and 5 percent.

Forest Floor

• Less than 2 percent of sunlight makes its way through the upper layers to the forest floor, thus very little vegetation grows other than moss and a few low-lying shrubs. This makes it easy to move around at this level, which attracts large animals such as elephants, gorillas and large cats, depending on the geographical location. Much debris makes its way to the forest floor from the upper layers and rapidly decomposes into the soil with the help of termites, earthworms and fungi, combined with the prevailing heat and humidity.

Dangers of Deforestation

• Each felled tree removed from the rainforest disturbs this intricate ecosystem as sunlight suddenly is able to penetrate to the forest floor. Removed trees no longer return to the soil to decompose, robbing soil of needed nutrients. Significantly less oxygen is being released, resulting in current levels of deforestation accounting for 18 to 25 percent of global annual carbon dioxide emissions, according to the Rainforest Concern website. Habitat is being disrupted for many species, including humans. For the sake of Earth's inhabitants and well-being, sustainable alternatives must be sought.