Soil phosphorus levels drive tree species’ different growth patterns
Don’t blame a lack of rain: A tropical forest of dry, bare-branched trees might be that way because of soil chock full of phosphorus.
In Panama’s dry season, leafy woodlands stand starkly next to forests of naked trees. Scientists had thought that rainfall caused the contrasting growth patterns because different soils there have different abilities to hold water. Narrow bands of rocky outcrops shoot through Panama’s soil, and rocky soils often hold little water.
But when ecologist Richard Condit of the Smithsonian Tropical Research Institute in Panama City and his colleagues analyzed samples from 72 forest sites across Panama, they found that so