Blender Cycles 150 samples - two render layers, one specifically for grass, which taxed my machine considerably.
main layer: 1350MB peak memory, ~40 mins on GPU (Titan)
grass: 5870MB peak memory, ~22 mins on CPU (i5 quadcore)
Intended use: backgrounds for animation. Render a background for specific shots, then use as background planes in animation.
Multiple particle systems. Trees for the whole environment, plants, grass and rocks separate vertex groups per major camera positions.
