All I know about bonsai is that it is the art of growing miniature versions of big trees. Is it possible to grow a whole miniature rainforest? If yes, has it been tried? If no, why not? I’ve a tiny backyard and it’s waiting… 
I imagine the amount of work needed to cultivate enough trees, coupled with the fact that a rainforest is just as much about the undergrowth (which can’t be made in bonsai) would make it almost impossible.
Cool idea though.
Please grow one and post pics! 
Tristan - Why can’t the undergrowth be bonsai’d? (sorry if that’s a stupid question, but I thought you could bonsai any plant)
Violet - Sure I’ll post pics - even if my “bonsai rainforest” has only one tree!
Do you even know what a rainforest is? What is your definition?
“A dense evergreen forest occupying a tropical region with an annual rainfall of at least 2.5 meters (100 inches).”
Got that off dictionary.com
However, I did have a rough idea of what a rainforest is even before that, given that I have spent a considerable time working in the sholas of the Western Ghats.
Here’s a bonsai cypress forest, for what it’s worth.
Well, I just don’t think you could make the mosses, shrubs and other undergrowth plants in bonsai.
I could be wrong. I don’t know much about the art.
Yeah - looks like it.
I’ve just been Googling away and the biggest bonsai “forest” I came across has all of seven trees in it.
And they do seem to be doing it only to trees.
Well, there goes my backyard bonsai rainforest!
Quite a lot of rainforest plants have very large leaves; this alone makes them rather unsuitable for bonsai, but in addition, it would be quite hard to prune and maintain the whole thing if it consists of multiple dense layers. There might also be a problem with the lower layers receiving enough light (things don’t all scale down at the same rate).
Probably the best you could hope for is a faux rainforest, creating the layered canopy effect with ordinary non-rainforest species, maybe including some miniature ferns and mosses too…
On high windswept mountain peaks in the tropics one can find a stunted form of cloud forest called “elfin forest,” in which the trees may be quite short (but not as short as the usual bonsais.)