Rainforests are forests qualified by high rainfall, with definitions adjusting minimum normal annual rainfall between 1750–2000 mm
The undergrowth in a rainforest is controlled in many areas by the lack of sunlight at ground level. This makes it possible to walk direct the forest. If the leaf canopy is demolished or thinned, the ground beneath is soon colonized by a dense, tangled growth of vines, shrubs, and small trees called a jungle. There are two types of rainforest, tropical rainforest and temperate rainforest.
The rainforest is divided into 4 unlike parts each with dissimilar plants and creatures, adapted for life in that specific area:
* The ‘emergent layer’ contains a small number of very large trees which grow above the general canopy, reaching heights of 45-55 m, although on occasion a few species will grow to 70-80 m tall. They need to be able to withstand the hot temperatures and strong winds. Eagles, butterflies, bats, and certain monkeys inhabit this layer.
The canopy at the Forest Research Institute Malaysia
* The canopy layer contains the majority of the largest trees, typically 30-45 m tall. The densest areas of biodiversity are found in the forest canopy, a more or less continuous cover of foliage formed by adjacent treetops. The canopy, by some estimates, is home to 50 percent of all plant species, suggesting that perhaps half of all life on Earth could be found there. The fauna is similar to that found in the emergent layer, but more diverse. A quarter of all insect species are believed to exist in the rainforest canopy. Scientists have long suspected the richness of the canopy as a habitat, but have only recently developed practical methods of exploring it. As long ago as 1917, naturalist William Beebe declared that “another continent of life remains to be discovered, not upon the Earth, but one to two hundred feet above it, extending over thousands of square miles.” True exploration of this habitat only began in the 1980s, when scientists developed methods to reach the canopy, such as firing ropes into the trees using crossbows. Exploration of the canopy is still in its infancy, but other methods include the use of balloons and airships to float above the highest branches and the building of cranes and walkways planted on the forest floor. The science of accessing tropical forest canopy using airships, or similar aerial platforms, is called dendronautics.
* The understory layer lies between the canopy and the forest floor. The understory (or understorey) is place to a number of birds, snakes, and lizards, as well as predators such as jaguars, boa constrictors, and leopards. The leaves are much larger at this level. Insect life is also abundant. Many seedlings that will grow to the canopy level are present in the understory. Only about 5 percent of the sunlight shining on the rainforest reaches the understory. This layer can also be called a shrub layer, although the shrub layer may also be considered a separate layer.
* The forest floor layer gets only 2 percent of sunlight. Only plants adapted to low light can grow in this region. Away from riversides, swamps, and clearings where dense undergrowth is found, the forest floor is relatively clear of vegetation because of the low sunlight penetration. It also contains decaying plant and animal matter, which disappears quickly due to the warm, humid conditions promoting rapid decay. Many forms of fungi grow here which help decay the animal and plant waste. It takes up to 20 mins for rain to actually touch the ground from the trees.