Another experiment of mine using Houdini. It's basically some simple L-system generated trees; instanced on a deformed grid. Grid texture details are all procedural displacement shaders. I wanted to create a test animation to check how houdini instances using an random array of objects. In that case I have about 10 variations of the tree and it's picked randomly for each instance. It's super easy to do! I'll definetly use that technique in futur projects.
(Compositing done within houdini as well...)

L-system Instancing from jrgauthier on Vimeo.