Ingenious
Now I'm really looking forward to the rest of it.

Thanks Mike

I've been working on the remaining jungle and swamp trees this afternoon.  The jungle trees are just fillers to go between the palms and nothing all that special, but the swamp trees are a bit more important than that.  This is the wrong colour, because texturing in ngPlant is a pain and extremely basic, but it gives some idea.  

You're welcome

A great start, but I see something that is catching my eye far more than the repeating textures. Does it take 3 passes to render?

If it does, and you are now asking your screen how the heck I knew that, I'm looking at the horizontal bands across your map.
This can happen if you have really wide glows, shadows or edge fades in operation (which by the look of things you have), and it is caused by the width of each pass.  If the object casting the shadow, or the edge of the polygon with the edge fade on it isn't visible in the current pass width, CC3 can't see the sheet effect, even though the result of it falls within the pass.

You can check the pass width by typing EXPORTSETMPPP on your keyboard and hitting return.  Check the number that shows in the command line.  Unless you have changed it before the default value is 4000000 (4 million).  You can increase it by typing 40000000 (40 million) and hitting enter.  Try rendering the map again with the same settings as before.  Hopefully by increasing the width of the pass this way you will get the whole map in one pass and those horizontal lines will vanish.

I hope these new gum trees look about right. I had trouble deciding what basic colour they should be. I also did some more work on the saguaros. They should be a more realistic shape now.

I'm going to stop worrying about the relative scale. All the tree objects are roughly three sizes - small, normal and large. That's so you can still tell what they are on the map, despite their relative sizes being different in reality.