Oxisols are the heavily oxidized soils found in tropical and subtropical rainforest.
These soils have undergone heavy amounts of weathering and are very low in fertility outside of the very thin layer of organic material on the surface. Because water has leached most of the other minerals out of the soil, oxisols are very high in concentrations of aluminum andiron and are mined extensively in countries where rainforest are being chopped down. In the U.S., oxisols are limited to regions of Hawaii.