Abstract: In this study we sought to determine the relationships between topography, litter and humus depth and root density in diverse, primary, lowland Dipterocarp rainforest. Though known to be important for rainforest ecology, minimal research on how these factors are codependent is available. Varying slope gradient in a 52 ha plot in the Lambir Hills National Forest showed a negative correlation to both root density and above ground woody basal area in the surrounding trees. While the limited scope of our project prevents extensive application of our results, we were still able to demonstrate two important principles: (1) that great heterogeneity exists in tropical rainforests at both large and small scales and (2) that even local variation in an abiotic factor, such as topography, can have large ecological implications.