http://www.minecraftforum.net/forums/mapping-and-modding/minecraft-mods/wip-mods/2524489-wip-realistic-terrain-generation-0-0-13?comment=379

Lol gl with that haha :p

Perhaps RTG can adjust the chance of a tree spawning based on the slope of the ground where a slope above a certain threshold wouldn't spawn trees at all (smaller bushes can have a higher threshold). That would make those nice looking height transitions. Also spawning surface cover like grass/dirt/snow depending upon the slope (for snow it should be a combination of altitude and slope).

I think RWGcanyon forest is quite like this only need to get rid of the 2 extra pleatues.

Closing this, but it's been labelled for easy reference.

i thought that was a real picture...

Yeah, me too when I first saw it :)