Tropical rainforests lie along the equator, mainly between the Tropics of Cancer and Capricorn. Rainforests have four main layers: the emergent, the canopy, the under canopy and the forest floor.

and a ground layer of herbaceous vegetation. Tropical forests have the highest biodiversity and primary productivity of any of the terrestrial biomes. Net primary productivity ranges from 2–3 kg ...

A study in Forest Ecosystems shows that particulate organic carbon (POC) dominates surface soils, while mineral-associated ...