What makes the soil in tropical rainforests so rich?

Fungi are at the root of tropical forest diversity—or lack thereof

Tropical rainforests are still vanishing at an alarming rate - Vox

Should Conservation Exclude Agriculture?, by Chris Wilmoth

Why is the temperate forest soil rich than that of the tropical

Human Impacts - Tropical Rainforest Biome

Why is the temperate forest soil rich than that of the tropical

Rainforest

Rainforest

The nutrient cycle in the rainforest - Internet Geography

Layers of the Rainforest, Rainforest Animals

Can soil be too rich, and how does it affect plants? - Quora

Rainforests - NatureWorks

Tropical rainforest biomes (article)

Should Conservation Exclude Agriculture?, by Chris Wilmoth

Why is the tropical rainforest soil poor and thin? - Quora