Chapters Hierarchical Instancing
Instancing can take place on several levels. Thus not only can different plants be represented over a single geometry, but instancing can also be implemented within tree structures: Leaf instancing is used to define a small branch; branch instancing is applied to define a larger branch, and so on. This way, optimal compression is achieved for the geometry of a tree.
The concept can be extended in that for each instancing object several representatives are generated to increase the variability of the total geometry. This step was applied in  in order to simplify an image-based rendering method.