The tropical rainforest is a biome of great complexity, and features several distinct topological landforms, including mountains, valleys, wetlands, streams, rivers, and flood plains. Rainforests in South America, Asia, Australia, Africa, and the Pacific Islands all feature mountains. Mount Margherita in the Congo rainforest of Uganda is a good example of the type of non-volcanic mountains that can occur in the rainforest biome.
Valleys (also called dales) in the rainforest can take either a 'Y' or a 'U' shape. When the valley provides a channel for the flow of a river or stream, it is called a 'dale.' Wetlands are an important part of the rainforest biome, and features soil that has been saturated by water, creating a rich, fertile environment for plants and animals. Streams and rivers are also prominent landforms of the rainforest, and provide sustenance for animals and plant life. The riverbank plays an important role in the cycle of predator and prey in the rainforest. The flood plain is a vast, flat area adjacent to rivers and streams. These areas are frequently flooded during times of high rains, and the saturated earth provides a welcome environment for growing microbes necessary to the environmental balance of the forest.