Divergent controls on carbon concentration and persistence between forests and grasslands of the conterminous US

Chicken or the egg. Grassland soil carbon behaves different than forest soil carbon. But is that because of the plant composition? (No). Or is it because of the climatic differences? (Probably) But if the climatic differences *also* lead to vegetation differences, then how can you separate out the climate from the vegetation? Here we attempt to do so.