I'll be making about 50 bases worth, containing a mix of plastic fish tank foliage and Games Workshop jungle trees. The former are on the bases already and the latter are assembled (although foolishly I didn't paint them on the sprues first and it'll take a lot longer this way!).
To get started, and provide myself with a bit of inspiration, I've finished a couple of samples and I think they look OK. Some will have rocks/boulders on them as well but this first pair just have the trees.
With a 28mm figure for scale:
Clumps of these bases should provide a decent jungle effect, and I can use taller normal trees behind them to add some height to the canopy. I'm a fan of multi-purpose hobby stuff, so these are nice and generic and might get some use in other scales and periods too, eg:
Only another 48 to go....