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.
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.
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Continued: Soils and Nutrient Cycling
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Copyright Rhett Butler 1994-2005