Primary rainforest in Brazil. (Photo by R. Butler)
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THE FOREST FLOOR
The forest floor of primary tropical rainforest is rarely the thick, tangled jungle of movies and adventure stories. It is actually quite the opposite: the floor is relatively clear of vegetation due to the deep darkness created by perhaps 100 feet (30 m) of canopy vegetation above. The canopy not only blocks out sunlight, but damps wind and rain. A visitor to the rainforest during a rainstorm will usually not immediately feel falling rain because so much is deflected and collected by various canopy plants. The blocking of wind by the canopy makes the forest floor a calm place where only the slightest breeze blows during tropical thunderstorms. When hiking in primary tropical rainforest a flashlight may be more useful than a machete since the subdued lighting limits ground growth. Instead of choking vegetation, a visitor will find large tree trunks, interspersed hanging vines and lianas, and countless seedlings and saplings and a relatively small number of ground plants.
The term "jungle" is frequently applied to forest areas having dense ground growth. Such "jungle" is characteristic of disturbed forest, usually near the forest edges, in recently opened light gaps, river banks, and areas where the forest is reclaiming previously cleared land. Vigorous ground growth is only possible where plenty of light is available—where there is a break or thinning in the light-absorbing canopy which screens out all but the 0.5-5 percent of light that reaches the floor in the primary forest.
CHARACTERISTICS
Despite its constant shade, the ground floor of the rainforest is the site for important interactions and complex relationships. The forest floor is one of the principal sites of decomposition, a process paramount for the continuance of the forest as a whole. It is also home to thousands of plants and animals, and provides support for trees responsible for the formation of the canopy. The ground level is the region of the forest which was first explored and has been the most intensively studied.
Review questions:
- What is the difference between jungle and rainforest?
- Why is there generally little light on the forest floor?
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Continued: Soils and Nutrient Cycling
This article was written by Rhett A. Butler [bibliographic citation for this page] and was last updated on the most recent date listed in the column on the right side.
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Recent news
Some toilet paper production destroys Indonesian rainforests, endangering tigers and elephants
(02/09/2012) American consumers are unwittingly contributing to the destruction of endangered rainforests in Sumatra by purchasing certain brands of toilet paper, asserts a new report published by the environmental group WWF. The report, Don't Flush Tiger Forests: Toilet Paper, U.S. Supermarkets, and the Destruction of Indonesia's Last Tiger Habitats, takes aim at two tissue brands that source fiber from Asia Pulp & Paper (APP), a paper products giant long criticized by environmentalists and scientists for its forestry practices on the Indonesian island of Sumatra. The brands — Paseo and Livi — are among the fastest growing, in terms of sales, in the United States.
Tropical ecologist: Australia must follow U.S. and EU in banning illegally logged wood
(02/09/2012) Australia should join the widening effort to stamp out illegal logging, according to testimony given this week by tropical ecologist William Laurance with James Cook University. Presenting before the Australian Senate's rural affairs committee, Laurance argued that the massive environmental and economic costs of illegal logging worldwide should press Australia to tighten regulations against importing illegally logged timber at home.
Humans drove rainforest into savannah in ancient Africa
(02/09/2012) Three thousand years ago (around 1000 BCE) several large sections of the Congo rainforest in central Africa suddenly vanished and became savannah. Scientists have long believed the loss of the forest was due to changes in the climate, however a new study in Science implicates an additional culprit: humans. The study argues that a migration of farmers into the region led to rapid land-use changes from agriculture and iron smelting, eventually causing the collapse of rainforest in places and a rise of grasslands. The study has implications for today as scientists warn that the potent combination of deforestation and climate change could flip parts of the Amazon rainforest as well into savannah.
Green groups: government moving too slowly on protecting Canada's Great Bear rainforest
(02/08/2012) Three environmental groups have submitted a letter to British Columbia Premier, Christy Clark, to ask the government to speed up the process of implementing the Great Bear Rainforest Agreement, which is meant to ensure 70 percent of old-growth forest is maintained.
Majority of protected tropical forests "empty" due to hunting
(02/08/2012) Protected areas in the world's tropical rainforests are absolutely essential, but one cannot simply set up a new refuge and believe the work is done, according to a new paper in Bioscience. Unsustainable hunting and poaching is decimating tropical forest species in the Amazon, the Congo, Southeast Asia, and Oceana, leaving behind "empty forests," places largely devoid of any mammal, bird, or reptile over a few pounds. The loss of such species impacts the whole ecosystems, as plants lose seed dispersers and the food chain is unraveled.
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