The monsoon troughalternatively known as the intertropical convergence zoneplays a significant role in creating the climatic conditions necessary for the Earth 's tropical rainforests. Tropical rainforests have been called the "jewels of the Earth" and the " world's largest pharmacy ", because over one quarter of natural medicines have been discovered there. The undergrowth in some areas of a rainforest can be restricted by poor penetration of sunlight to ground level. If the leaf canopy is destroyed or thinned, the south east asian rainforest destruction beneath is soon colonized by a dense, tangled growth south east asian rainforest destruction vinesshrubs and small trees asian fucking a camel, called a jungle. The term jungle is also sometimes applied to tropical rainforests generally. Rainforests as well as endemic rainforest species are rapidly disappearing due to deforestationthe resulting habitat loss and pollution of the atmosphere.