A study looked at how environmental factors affect tree species in a mixed forest in central China. They found that soil nutrients and terrain shape play a role in species diversity. Soil nutrients decrease species richness but increase species dominance and rarity. Terrain shape affects species diversity through soil nutrients, with convex areas having more diverse species. Slope has a negative impact on species even without soil nutrients. Overall, soil nutrients are more important than terrain in shaping species diversity in this forest.