Nice, but WAY to high poly, and the middle part needs variation. When you export you may get frustrated, once you export you have to write your map's name in the file name, (with no SPACES! And if you want one, put a _ sign there) and at the end this:
.JMS (has to be CAPITOLIZED!!)
Otherwise it's not recognized as a .jms file, even though it's just a bunch of xyz coordinates written down, which I could easily read, but the computer can't because it doesn't have the '.JMS' tag on it.
To lower the poly count on some of those square like surfaces (the floor for example, just delete the entire skybox, except the roof poly's) delete all the poly's that make up the sides, the floor, but not the roof. Then, connect and make walls out of the four vertices, on the bottom of the box. Then simply connect em with polygons (under the modifiers thingy toolbar thing at the right, go into face mode, and click 'create' then simply click the vertex that will be the first part of the poly, then the second, then the thrid, and wallah! You have a poly!).
Wallah! You now have a new floor! You can tesselate as you like! But before you do, tesselate once then use the 'cut' tool to cut a the shape you want of the forest thing, then simply extrude, if your aiming for the 'straight up' look. THey used this trick in many older games, like zelda the ocarina of time. They made the forest as a boundary (just a wall like structure.) then skinned it to look like a forest, even though it looked so damn fake!
GL!
Oh and I don't know how to avoid open edge errors, with that create polyong thingy

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