Tropical rainforests are found in areas with high temperatures between 20-30 degrees Celsius and high rainfall between 1000-2000 mm annually. They have 3 main layers - the emergent layer with the tallest trees up to 50m high and buttress roots, the canopy layer 15-30m tall that blocks 70% of sunlight, and the undergrowth layer that receives very little sunlight. Rainforests are threatened by deforestation for agriculture, logging and development which causes extinction of plants and animals. Singapore had rainforests but they were cleared for population and industry growth, though reserves like Bukit Timah Nature preserve remnants for water catchment, recreation and heritage.
