<p>Forests enhance the effects of topography on the flow field, and even very gentle topography can cause flow separation and the development of shear layers. Most numerical studies are based on isolated hills or sinusoidal topography, and simulations using real topography produce overwhelmingly complex flow fields that are difficult to interpret. We propose a simple geometry for topographical features that is more flexible than the current geometries in idealized studies and results in a low-dimensional parameter space to classify real topographic features. We analyze the topography of Central Amazonia and show that it is dominated by wide plateaus bounded by narrow valleys, a largely unexplored configuration. Large-eddy simulations under neutral conditions are used to explore a portion of the parameter space, including hills, valleys, and periodic topography. These topographic features lead to different patterns of flow recirculation within the forest. While some types of topography increase the total turbulence kinetic energy (TKE) in the roughness sublayer compared to flat terrain (as is usually observed in flow over hills), this is not always the case. The TKE budget reveals that the competition between enhanced shear production above the canopy and reduced shear production inside the canopy determines the overall increase or reduction in TKE. We explore the consequences of these different flow characteristics for canopy air exchange and total drag on mean flow.</p>