African savannah isn’t the homogenous, steady monotony that it appears on the Discovery Channel. (Well, back when the discovery channel showed nature documentaries, anyway.) Dirt roads and hills criss-cross it, and fever trees like this one grow where more water is available. The yellow-green bark comes from photosynthetically active cells. The name comes from an interesting illustration of the post hoc ergo propter hoc fallacy: when early European settlers went near water, they tended to contract malaria (thus the fever). They incorrectly attributed this to the trees, rather than the mosquitos breeding in the water.